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Paeonia qiui is one of the important ancestors of cultivated species of tree peony, serving as an important genetic resource in peony cross breeding, due to its purple-red leaves. The pollen is widely known to directly influence reproductive success and genetic structure of the main plant population. This study aims to investigate the storage characteristics of Paeonia qiui pollen, further to elucidate the physiological mechanism of pollen storage at different temperatures, in order to determine the accurate and efficient storage method for the viability of Paeonia qiui pollen. In this study, the pollen morphology of Paeonia qiui was characterized using scanning electron microscopes. Four factors (sucrose, boric acid, Ca (NO3)2, GA3) at three different levels were selected in the orthogonal test to investigate the characteristics of Paeonia qiui in vitro germination. The experiment was conducted to explore the effect of storage temperatures and duration on the pollen germination rate, malondialdehyde (MDA), and the activity of superoxide dismutase (SOD), peroxidase(POD), catalase (CAT). The results show that the rates of abnormal and shrunken pollen were as high as 19.5%, indicating the low viability of Paeonia qiui pollen. The important factors affecting the germination rate of Paeonia qiui pollen were listed in order, sucrose, boric acid, Ca (NO3) 2, GA3. The optimum concentrations of media were achieved in vitro pollen germination, when containing 110 g/Lsucrose, 45 mg/L boric acid, 55 mg/L GA3, 30 mg/L Ca(NO3)2. The optimum temperatures were 2℃ and -20℃ for the pollen storage of 1-2 months and 4-6 months, respectively. The optimum condition was -80℃ for the intermediate storage within one year, whereas the promising temperature was -196℃ for the long-term preservation of Paeonia qiui pollen. The germination rate was 75.5% after 365 days of storage, indicating that the optimum condition can effectively prolong pollen longevity. The germination rate of pollen was positively correlated with three protective enzymes, while negatively correlated with malondialdehyde content. The influence of three protective enzymes on pollen germination rate was ranked in order: superoxide dismutase (SOD), catalase (CAT), peroxidase (POD). The sensitivity of three protective enzymes was different at different storage temperatures. Specifically, SOD served as a sensitive protective enzyme at 2, -20℃ and -80℃, whereas POD served as sensitive protective enzymes at room temperature. The protective enzyme activity decreased, while the malondialdehyde content increased, leading to the active oxygen can not be effectively removed. This process was one of the main reasons for the decrease in pollen viability after storage at room temperature, 2, -20 and -80℃. The malondialdehyde content and the activity of three protective enzymes in pollen remained basically stable. The three protective enzymes can effectively maintain the internal balance of oxidative metabolism, and thereby reduce the levels of oxidative damage. This can be the internal cause to keep high germination rate after cryopreservation. This finding can provide a promising experimental and theoretical basis for cross-temporal pollination hybridization and germplasm resource conservation. [ABSTRACT FROM AUTHOR]

In this paper, the graphite lube was modified by zirconium oxychloride, ammonium molybdate and sodium tungstate respectively, and then the graphite tubes before and after modification were characterized by X-ray diffraction(XRD) and scanning electron microscope(SEM). The analytical performance of modified graphite tube was studied through the determination of lead in electronic grade dielhylene glycol ether. The research results showed that: The formation of molybdenum carbide, tungsten carbide and zirconium oxide of high strength and high melting point on the surface of graphite tube after modified by ammonium molybdate, zirconyl chloride sodium tungstate could improve the sensitivity and accuracy of determination. The relative standard deviation of the graphite tube modified by zirconium oxychloride was ⩽3.21%. The linear correlation coefficient was 0.981 4, and the recovery rate was 98.7%-110.6% ; the relative standard deviation of the graphite tube modified by ammonium molybdate was ⩽2.20%. The linear correlation coefficient was 0.999 4, and the recovery rate was 99.3%-106.4%; the relative standard deviation of the graphite tube modified by sodium tungstate was ⩽3.38%. The linear correlation coefficient was 0.994 7, and the recovery rate was 98.5%-106.8%. The analytical performance of the graphite tube modified by ammonium molybdate was the best. [ABSTRACT FROM AUTHOR]

Cellulose/sodium alginate (Cellu/SA) composite aerogels were prepared via freeze-drying technique as a valid method to develop 3D scaffolds for tissue engineering. Cellulose with hydroxyl groups showed weak apatite nucleation ability in simulated body fluid(SBF). In order to induce the formation of apatite crystal, oxidation modification of Cellu/SA composite aerogels was carried out with sodium periodate and sodium chlorite. The hydroxyl groups at C2 and C3 of Cellulose and SA were oxidized into carboxyl groups, leading to improve mineralization ability. The morphology and structure were characterized by Fourier Transform Infrared (FT-IR) spectrometer, Scan Electron Microscope (SEM), X-Ray Diffraction (XRD) and X-ray photoelectron spectroscopy. Results show that the formation of HA on the surface of dicarboxylic Cellu/SA composite aerogels is faster with smaller grain size, and the deposition layer is more uniform after mineralization for 7 d. The Cellu/SA composite aerogels thus possess an ultrafine 3D nanoporous network structure. It is noticeable that the dicarboxylic Cellu/SA composite aerogel is a promising candidate for orthopedic biomaterial application with a Ca/P molar ratio of 1.35. In addition, the aerogel has good biocompatibility demonstrated by CCK8 assay and Live/Dead fluorescence staining of L929 cells. The L929 cells activity of both Cellu/SA and dicarboxylic Cellu/SA composite aerogels extracts are higher than 80%. When the culture duration is prolonged to 72 h, an obvious increase in the intensity of green fluorescence is observed, suggesting that the number of cells is increased. The biocompatible mineralized dicarboxylic Cellu/SA composite aerogels can promote cell growth and differentiation and are potential to be applied as a bone repair material. [ABSTRACT FROM AUTHOR]

A kind of clay modified by Cetyltrimethyl Ammonium Ahloride(CTAC) was prepared to solve the problem of sand fixation in desert highway construction and maintenance. H1, H2, H3, H4 and H5 were assigned to the treatments with mass ratios of CTAC to clay 2:4, 3:4, 4:4, 5:4 and 6:4, respectively. In addition, unmodified clay was prepared as the control group H. Water retention performance was tested in an artificial climate box to simulate the desert climate. And the changes of mass and compressive strength were compared before and after ageing to test the anti-aging property. The grass planting experiment was conducted to analyze the effect of materials on germination rates. At last, the mechanism of sand fixation and water retention was analyzed by X-ray diffractometer, infrared spectrum analyzer and scanning electron microscope. The results showed that the water retention property was obviously improved with the increase of CTAC content. The moisture content of H5 and H4 were 27% and 23% respectively, while H1 was 7% on the 7th day, indicating the water retention performance of modified clay samples were gradually enhanced with the increase of CTAC content. In the compressive strength test, the strength of the unmodified clay group H was failed to measure due to the strength less than 0.1 MPa, while the strengths of the modified clay samples were significantly improved, and the strengths of the modified clay samples all met the standard requirements (no less than 1 MPa). Moreover, the strength of the modified clay increased with the increase of the content of CTAC, with the highest and higher strength of H5 and H4 (2.2 and 2.1MPa respectively), and the lowest strength of H1 (1.7 MPa). This indicated that CTAC could bond dispersed clay particles together to form a consolidation layer, and its strength could meet the requirements of mechanical construction. In the anti-aging performance test, after aging for 500 h, no obvious cracks were found on the surface of the samples, and the water retention performance decreased by less than 5%. The strength and mass loss rate of all the groups increased with aging time, and the higher the CTAC content, the higher the strength and mass loss rate. The strength loss rates of H4 and H5 were respectively 7.3% and 10.4%, and the mass loss rates of H4 and H5 were respectively 2.6% and 3.2% after 500 h of aging. The grass planting experiment showed the germination rate of the unmodified clay group (H) was only 7%, far below that of modified groups. With the increase of CTAC content, the germination rate of grass seeds gradually increased. The germination rate of the modified group H1 was 33%, and the highest germination rate was up to 47% (H4). But there was no more increase when CTAC content increase further, and the germination rate of H5 group was 41%. The microscopic analysis showed that CTAC could bond the loose clay particles together through intercalating effect. The clay gaps were turned into hydrophobicity, which resulted in the increase of the water transport resistance. So the modified clay had better sand-fixation and water-retention performance. However too much CTAC blocked the space of clay particles, the permeability of clay decreased, so the germination rate of H5 decreased. Although the compressive strength and water retention performance of H5 is slightly better than H4, as a kind of sand fixation material, the most important performance is the survival rate of seedlings. Therefore, under the premise that all other performances meet the standard requirements, H4 with the highest germination rate was selected as the best treatment scheme. The results could provide reference for the application of the modified sand-fixing materials. [ABSTRACT FROM AUTHOR]

In order to reveal the developmental process of the deuterogenic placenta of Adinandra latifolia from the family Pentaphylacaceae, and the relationship between deuterogenic placenta, carpellary placenta and free central placenta, the flower buds and mature fruits of A. latifolia were observed in detail by scanning electron microscope(SEM)and stereoscopic microscope. Floral buds at different stages of development were collected and fixed in formalin-aceticacid-alcohol, and then dehydrated through an ethanol/amylacetate series, critical point dried with CO2, Au/Pt sputter coated, prepared samples were examined with SEM. Mature fruits were dissected under a stereoscopic microscope directly without preparation. The results showed that during the floral development, 5 carpel primordia were growth rapidly after the stamens initiation, and then ovary was combined with the axial placenta on the upper part and cavity on the bottom part. After the placenta grew on the carpels(named carpellary placenta), several mounds appear at the top of the receptacle within the position opposite to the carpel in the lower cavity. The mounds combined gradually into a hemispherical deuterogenic placentation. And some fertile ovules appeared on the surface of both the carpellary placenta and deuterogenic placenta. Finally, in mature fruits the fertile ovules turn to seeds on both types of placenta in which vascular bundles are discrete. Therefore, deuterogenic placenta appeared independently and was later than the carpellary placenta. The development of deuterogenic placenta in A. latifolia was different from that of the free central placenta in both Caryophyllaceae and Phytolaccaceae(the axial placenta turned into a free central placenta by the septa disappear), but it is basically identical to that of Primulaceae, Theophrastaceae, Maesaceae, Myrsinaceae from Ericales(the free central placenta formed on top of the receptacle directly). [ABSTRACT FROM AUTHOR]

Ｔｈｅ ｃｏｒｒｏｓｉｏｎ ｂｅｈａｖｉｏｒ ｏｆ ａ Ｘ６５ＭＳ ｐｉｐｅｌｉｎｅ ｓｔｅｅｌ ｉｎ ｓａｔｕｒａｔｅｄ Ｈ２Ｓ / ＣＯ２ ｅｎｖｉｒｏｎｍｅｎｔ ｉｓ ｓｔｕｄｉｅｄ ｂｙ ｓｉｍｕｌａｔｉｎｇ ｏｉｌ ａｎｄ ｇａｓ ｄｅｌｉｖｅｒｙ ｅｎｖｉｒｏｎｍｅｎｔ ｗｉｔｈ ｈｉｇｈ ｔｅｍｐｅｒａｔｕｒｅ ａｎｄ ｈｉｇｈ ｐｒｅｓｓｕｒｅ ｒｅａｃｔｏｒ. Ｔｈｅ ｃｏｒｒｏｓｉｏｎ ｒａｔｅ ｕｎｄｅｒ ｄｉｆｆｅｒｅｎｔ ｉｍｍｅｒｓｉｏｎ ｔｉｍｅ ｐｅｒｉｏｄｓ ｉｓ ｍｅａｓｕｒｅｄ ｂｙ ｔｈｅ ｍａｓｓ ｌｏｓｓ ｍｅｔｈｏｄꎬ ａｎｄ ｔｈｅ ｐｈａｓｅ ｃｏｍｐｏｓｉｔｉｏｎ ａｎｄ ｍｏｒｐｈｏｌｏｇｙ ｏｆ ｃｏｒｒｏｓｉｏｎ ｐｒｏｄｕｃｔｓ ａｒｅ ａｎａｌｙｚｅｄ ｂｙ ｍｅａｎｓ ｏｆ Ｘ-ｒａｙ ｄｉｆｆｒａｃｔｉｏｎ (ＸＲＤ)ꎬ ｓｃａｎｎｉｎｇ ｅｌｅｃｔｒｏｎ ｍｉｃｒｏｓｃｏｐｅ (ＳＥＭ)ꎬ ｅｎｅｒｇｙ ｄｉｓｐｅｒｓｅ ｓｐｅｃｔｒｏｓｃｏｐｙ (ＥＤＳ) ａｎｄ ｅｌｅｃｔｒｏｎ ｐｒｏｂｅ ｍｉｃｒｏａｎａｌｙｓｉｓ ( ＥＰＭＡ)ꎬ ｒｅｓｐｅｃｔｉｖｅｌｙ. Ｔｈｅ ｒｅｓｕｌｔｓ ｓｈｏｗ ｔｈａｔ ｔｈｅ ｃｏｒｒｏｓｉｏｎ ｒａｔｅ ｃａｎ ｂｅ ｄｉｖｉｄｅｄ ｉｎｔｏ ｔｈｒｅｅ ｓｔａｇｅｓꎬ ｉ. ｅ. ｔｈｅ ｉｎｉｔｉａｌ ｃｏｒｒｏｓｉｏｎ ｒａｔｅ ｄｅｃｒｅａｓｅｓ ｒａｐｉｄｌｙꎬ ｔｈｅｎ ｃｈａｎｇｅｓ ｓｌｏｗｌｙ ａｎｄ ｆｉｎａｌｌｙ ｆｌａｔｔｅｎｓ ｏｕｔ. Ｔｈｅ ｃｏｒｒｏｓｉｏｎ ｐｒｏｃｅｓｓ ｉｓ ｍａｉｎｌｙ ｃｏｎｔｒｏｌｌｅｄ ｂｙ Ｈ２Ｓ ｃｏｒｒｏｓｉｏｎꎬ ａｎｄ ｔｈｅ ｐｒｏｄｕｃｔｓ ａｒｅ ｄｏｍｉｎａｔｅｄ ｂｙ ｆｅｒｒｏｓｕｌｆｕｒ ｃｏｍｐｏｕｎｄ (Ｆｅｘ Ｓｙ ). Ｗｉｔｈ ｔｈｅ ｉｎｃｒｅａｓｅ ｏｆ ｉｍｍｅｒｓｉｏｎ ｔｉｍｅꎬ ｔｈｅ ｐｒｏｐｏｒｔｉｏｎ ｏｆ ｉｒｏｎ ｄｅｃｒｅａｓｅｓꎬ ｔｈｅ ｐｒｏｐｏｒｔｉｏｎ ｏｆ ｓｕｌｆｕｒ-ｒｉｃｈ ｐｈａｓｅ ｉｎｃｒｅａｓｅｓꎬ ｔｈｅ ｆｉｌｍ ｔｈｉｃｋｎｅｓｓ ｏｆ ｃｏｒｒｏｓｉｏｎ ｐｒｏｄｕｃｔｓ ｉｎｃｒｅａｓｅｓꎬ ａｎｄ ｔｈｅ ｓｔｒｕｃｔｕｒｅ ｃｈａｎｇｅｓ ｆｒｏｍ ｌｏｏｓｅ ｔｏ ｕｎｉｆｏｒｍ ａｎｄ ｃｏｍｐａｃｔ ｇｒａｄｕａｌｌｙ. Ｔｈｅ ｃｏｒｒｏｓｉｏｎ ｐｒｏｄｕｃｔｓ ａｒｅ ｍａｃｋｉｎａｗｉｔｅ →ｔｒｏｉｌｉｔｅ →ｐｙｒｒｈｏｔｉｔｅꎬ ａｎｄ ｔｈｅ ｓｔａｂｌｅ ｐｙｒｒｈｏｔｉｔｅ ｈａｓ ａ ｐｒｏｔｅｃｔｉｖｅ ｅｆｆｅｃｔ ｏｎ ｔｈｅ ｃｏｒｒｏｓｉｏｎ ｒｅｓｉｓｔａｎｃｅ ｏｆ Ｘ６５ＭＳ ｐｉｐｅｌｉｎｅ ｓｔｅｅｌ ｍａｔｒｉｘ. [ABSTRACT FROM AUTHOR]

Ｏｐｔｉｃａｌ ｍｉｃｒｏｓｃｏｐｅ ( ＯＭ )ꎬ ｓｃａｎｎｉｎｇ ｅｌｅｃｔｒｏｎ ｍｉｃｒｏｓｃｏｐｅ ( ＳＥＭ )ꎬ ｔｒａｎｓｍｉｓｓｉｏｎ ｅｌｅｃｔｒｏｎ ｍｉｃｒｏｓｃｏｐｅ (ＴＥＭ)ꎬ ｍｉｃｒｏ￣ｉｎｄｅｎｔａｔｉｏｎ ｔｅｓｔｅｒ ａｎｄ Ｘ￣ｒａｙ ｓｔｒｅｓｓ ｍｅｔｅｒ ｗｅｒｅ ｅｍｐｌｏｙｅｄ ｔｏ ｉｎｖｅｓｔｉｇａｔｅ ｔｈｅ ｍｉｃｒｏｓｔｒｕｃｔｕｒｅ ｏｆ ｂａｃｋｕｐ ｒｏｌｌｓ ’ ｓｕｂｓｕｒｆａｃｅ ａｆｔｅｒ ｒｏｌｌｉｎｇ ｃｏｎｔａｃｔ ｆａｔｉｇｕｅ. Ｔｈｅ ｍａｘｉｍｕｍ ｖａｌｕｅ ｏｆ ｆａｔｉｇｕｅ ｄａｍａｇｅ ｗａｓ ｌｏｃａｔｅｄ ｏｎ ｔｈｅ ｓｕｂｓｕｒｆａｃｅ ｏｆ ｔｈｅ ｂａｃｋｕｐ ｒｏｌｌ ｗｈｉｃｈ ｗａｓ ａｂｏｕｔ ４００ μｍ ａｗａｙ ｆｒｏｍ ｔｈｅ ｓｕｒｆａｃｅ. Ｔｈｅ ｉｎｃｒｅａｓｅｄ ｈａｒｄｎｅｓｓꎬ ｒｅｄｕｃｅｄ ｒｅｓｉｄｕａｌ ｓｔｒｅｓｓ ａｎｄ ｅｌｅｖａｔｅｄ ｃｏｒｒｏｓｉｏｎ ｒｅｓｉｓｔａｎｃｅ ｏｆ ｔｈｅ ｓｕｂｓｕｒｆａｃｅ ｒｅｓｕｌｔｅｄ ｆｒｏｍ ｒｏｌｌｉｎｇ ｃｏｎｔａｃｔ ｆａｔｉｇｕｅ. Ｍｉｃｒｏｓｔｒｕｃｔｕｒｅ ｏｆ ｔｈｅ ｓｕｂｓｕｒｆａｃｅ ｗａｓ ｂｒｏｋｅｎ ｉｎｔｏ ｓｍａｌｌ ｐｉｅｃｅｓ ａｎｄ ｄｉｓｌｏｃａｔｉｏｎ ｄｅｎｓｉｔｙ ｗａｓ ｉｎｃｒｅａｓｅｄ. Ｕｎｄｅｒ ｏｎｅ ｃｏｎｓｔａｎｔ ｃｏｎｔａｃｔ ｓｔｒｅｓｓꎬ ｆａｔｉｇｕｅ ｄａｍａｇｅ ｏｆ ｂａｃｋｕｐ ｒｏｌｌ ｉｎｃｒｅａｓｅｄ ｗｉｔｈ ｔｈｅ ｉｎｃｒｅａｓｉｎｇ ｐｅｒｃｅｎｔａｇｅ ｏｆ ｆａｔｉｇｕｅ ｌｉｆｅ. [ABSTRACT FROM AUTHOR]

Superfine grinding is one of the effective techniques to change the microstructure and physicochemical properties of materials. In this study, the highland barley bran was selected as a raw material to prepare micropowder A and B, and then their microstructure and physicochemical properties were investigated to evaluate the processing feasibility of ultrafine powders for food supplements. Experimental methods, including laser particle size instrument (LPA), scanning electron microscope (SEM), thermogravimetric analysis (TG), differential scanning calorimetry (DSC), fourier transform infrared spectrometer (FTIR), X-ray diffraction (XRD) and rapid viscosity analyzer (RVA), were adopted to characterize the morphology and physicochemical properties of ground powders after superfine grinding. Moreover, many functional indexes were also evaluated during materials characterization, including chroma, resting angle, sliding angle, swelling force, packing density, compaction density, water solubility, water/oil holding capacity, cation adsorption capacity and the cholic acid adsorption capacity. Results show that the particle size of obtained bran powders gradually decrease, and powder textures are refined than before. The average particle size of coarse powders, micropowder A and B are 335.94μm, 72.52μm and 22.69μm, respectively. The maximum mass loss rates and temperature range of three types of barleybran powders indicate a slight difference in TG analysis. As the particle size decreases, the barley bran powders are more sensitive to thermal decomposition, while the thermal stability gradually decreases. FTIR confirmed that there was no new absorption peaks, and only relatively small changes in the intensity of the absorption peaks from two types of micropowders, when compared to the coarse highland barley bran powder. There was no position changes of main characteristic peaks, indicating that no chemical reaction occur in micropowder A and B. In XRD patterns, the diffraction peaks of 2θ at 16° and 18.8° show that the remained starch in the highland barley bran is A type crystalline, and the diffraction peaks of 2θ at 20.18°, 34.05°, 22.9°, and 18.8° are ascribed to the cellulose type I starch. The peak characteristics weaken with the decrease of particle size, as well the width of half peaks and the intensity of peaks in the diffraction patterns. Furthermore, there are also some changes in the enthalpies and peak temperatures of different powders after superfine grinding treatment, indicating that the enthalpies of coarse powder, micropowder A and B increase from 23.89 J/g to 32.95J/g. Gelatinization temperatures of slightly ground highland barley bran increase, whereas the initial temperature, peak temperature and the final temperature have a significant impact on the thermodynamic properties of the fine-powdered highland barley bran. As the grain size of highland barley bran decreases, the viscosity of obtained powders increases, including peak viscosity, valley viscosity, final viscosity and disintegration value. Superfine grinding treatment can reduce the regrowth value of highland barley bran. With the decrease of the grain size, the resting angle, sliding angle, adsorption water and oil holding capacity, expansion force, vibration density, accumulation density and cation exchange capacity of the fine powders also significantly reduce, indicating that superfine grinding can change the microstructure and physicochemical properties of residual starch in highland barley bran. This study can provide a theoretical basis and technical support to improve the full utilization of highland barley bran, and thereby to transfer micronized highland barley bran powders to serve as the food supplemental materials. [ABSTRACT FROM AUTHOR]

BACKGROUND: At present, there are many types of bone defect repair scaffolds, but a single type of material is difficult to meet the requirements of bone tissue engineering scaffold materials. Several suitable materials can be combined into a composite material by appropriate methods, taking into account the advantages and disadvantages of various materials. It is the focus of scholars in recent years. OBJECTIVE: To construct nano-hydroxyapatite/chitosan/polycaprolactone composite scaffolds and analyze characterization of composite scaffolds. METHODS: Nano-hydroxyapatite/chitosan/polycaprolactone porous ternary composite scaffold material was prepared by 3D printing and molding technology. The characterization of scaffold material was studied from X-ray diffraction analysis, stent water absorption rate, stent compressive strength, stent degradation performance in vitro, stent aperture analysis, scanning electron microscope analysis and other dimensions. RESULTS AND CONCLUSION: (1) X-ray diffraction analysis showed that the crystal-shaped peak map of nano-hydroxyapatite/chitosan/polycaprolactone scaffold materials was similar to the hydroxyapatite powder diffraction standard card, suggesting that the scaffold materials ware integrated with each other through physical interaction, and did not affect the biological function of hydroxyapatite. (2) The average water absorption rate of the scaffold was 18.28%, and the hydrophilicity was good. The maximum pressure that the scaffold could withstand was 1 415 N, and the degradation rate was similar to the osteogenic rate. (3) Under a microscope, a ternary scaffold material with an aperture of 250 μm was successfully produced. The pore size was uniform and distributed regularly. (4) Scanning electron microscope demonstrated that the fibers composed of chitosan and polycaprolactone ware arranged orderly and grid like, hydroxyapatita was distributed uniformly on the fiber surface in granular form, and the ternary composite material presented uniform and loose microporous structure. (5) Nano-hydroxyapatite/chitosan/polycaprolactone ternary composite scaffold material can be successfully prepared through 3D printing and molding technology, which has moderate compressive strength, certain porosity, appropriate degradation rate and water absorption rate, and can lay a foundation for repairing bone defects. [ABSTRACT FROM AUTHOR]

BACKGROUND: Our previous study confirmed that BTO/P(VDF-TrFE) piezoelectric nanocomposita membrane containing 5%BTO (BaTO3, BTO) nanoparticles could significantly promote bone marrow mesenchymal stem cells (BMSCs) adhesion, growth, osteogenic differentiation and repair of bone defects due to its bionic potential. However, for clinical applications, it is not clear whether there is any difference between the bone repair effect of this material as a guide for tissue regeneration and that of the existing clinically non-degradable membrane products. OBJECTIVE: To compare the effects of BTO/P(VDF-TrFE) piezoelectric nano-composne membrane materials with commercial PTFE membrane in repairing critical-sized defects of SD rat skull. METHODS: BTO/P(VDF-TrFE) piezoelectric nanocomposne membrane containing 5% BTO nanoparticles was prepared by solution casting method. Scanning electron microscope, atomic force microscope and water contact angle measuring instrument were used to observe the surface morphology, measure the surface roughness and surface hydrophilicity and hydrophobicity of the material. In SD rats (purchased from the Laboratory Animal Center, Beijing University Hospital of Stomatology, China), a 5-mm sized full-thick bone defect was made on both sides of the sagittal suture of the skull. The left bone defect was covered with PTFE membrane (control group). The right bone defect was covered with BTO/P(VDF-TrFE) piezoelectric nano-composita membrane (experimental group). At postoperative 4 and 12 weeks, micro-CT and histological methods were used to evaluate the repair of the skull defect in rats. This study was approved by Animal Ethics Committee, Beijing University Hospital of Stomatology. RESULTS AND CONCLUSION: The piezoelectric nanocomposite membrane had smooth and dense surface and BTO nanoparticles were evenly distributed. PTFE membrane was composed of loose coarse fibers. The piezoelectric nanocomposite membrane had lower surface roughness (P< 0.001) and higher hydrophilicity (P< 0.001) than PTFE membrane. Micro-CT and histological results showed that at 4 weeks after surgery, new bone formation was found in both groups, but new bone formation was more obvious in the center of the defect in the experimental group than in the control group. At 12 weeks after surgery, bone defects healed in both groups, but the maturity of newly formed bone in the experimental group was greater than that in the control group. These results suggest that BTO/P(VDF-TrFE) piezoelectric nanocomposite membrane containing 5%BTO (BaTO3, BTO) nanoparticles can be used as a membrane guiding tissue regeneration. [ABSTRACT FROM AUTHOR]

Hydrogel can significantly expand in water and maintain their original structures and properties. Hydrogels have a promising application in enrichment and separation of low concentration heavy metal ions, because of the large adsorption capacity, fast adsorption speed, easy analysis, rich source and being environmentally friendly. However, the traditional hydrogel adsorbents prepared from chitosan, cellulose and other natural polysaccharides have poor mechanical properties, so it is necessary to synthesize a hydrogel adsorbent having good mechanical properties, which restricte their application in heavy metal adsorption. In this work, cellulose-chitosan / polyacrylamide (Ce-Cs/PAAM) double network hydrogel was prepared by a one-pot method. 0.5 g of banana fiber cellulose and 0.5 g of chitosan were dispersed in 20 mL of 0.1 mol/L acetic acid (the precursor solution for the first network ) and stirred at 60 ℃ for 5 h. The chitosan could be dissolved quickly while the banana fiber cellulose was partially dissolved. Then 4.26 g of acrylamide (the precursor solution for the second network) and 3 mL of epichlorohydrin (crosslinking agent) were added into the solution by magnetic stirring at 25 ℃ for 1 h. After that, 0.02 g of N, N-methylene diacrylamide (crosslinking agent), 0.02 g of potassium persulfate (initiator), and 0.2 g of α-ketoglutaric acid (light initiator) were added to the mixed solution and stirred for 15 min.The first and second network were polymerized and crosslinked simultaneously. The obtained solution was placed at 25 ℃ for 24 hours. The two polymer networks generated upon UV-curing for 6 hours to further polymerized the second layer of networked (polyacrylamide) under the action of light initiator, followed by washing in deionized water twice a day for 7 days to produce a white opaque gel. Cellulose-chitosan (Ce-Cs) and polyacrylamide (PAAM) hydrogel were prepared as control. The structure of the three types of hydrogels were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM) and X-Ray Diffractometer (XRD). The changes of functional group composition, surface structure, crystallization degree, mechanical properties, swelling properties and adsorption properties of samples were investigated. The results showed that the Ce-Cs / PAAM hydrogel was a three-dimensional porous and double network structure with excellent mechanical strength and toughness. Under the compressive strain of 90%, the maximum compressive stress was reached to 60 MPa. The swelling ratio in water was 9.56 mg/mg, and the swelling ratio in alkaline solution (pH 12) reached to 15.34 mg/mg. The maximum adsorption capacity of Cu2+ ions on Ce-Cs/ PAAM hydrogel was 312.4 mg/g (Qe) under the concentration of C0 at 350 mg/L, pH at 5.5 and adsorption time for 90 min. Compared with polyacrylic acid / humus double network hydrogel (151.00 mg/g), the adsorption capacity of sample for Cu2+ ions was increased significantly. Therefore, the results indicated that Ce-Cs /PAAM double network hydrogel may be a promising Cu2+ ions adsorbent. [ABSTRACT FROM AUTHOR]

Magnetic Fe3O4 nano-particles were prepared by chemical coprecipitation method, and magnetic chitosan microspheres (Fe3O4@CS) and polyethyleneimine (PEI) modified magnetic chitosan microspheres (Fe3O4@CS/PEI) with different proportions were thereby prepared by Schiff base reaction in the emulsion system using glutaraldehyde as the crosslinking agent. The structure, particle size and magnetism of microspheres were characterized by infrared spectroscopy (FT-IR), X-ray powder diffraction(XRD), scanning electron microscope (SEM), dynamic laser scatter (DLS) and hysteresis loop. The adsorption amount of ibuprofen on microspheres and reuse rate were studied by ultraviolet spectrophotometer. The characterization results showed that the microspheres were successfully prepared by Schiff base reaction, which had no effect on the crystal phase of Fe3O4. The microspheres presented regular circle with narrow size distribution and they were magnetic. The thermodynamics adsorption model of ibuprofen on microspheres was Langmuir adsorption isotherm, and the kinetic adsorption model was second order dynamics model. With the increase of PEI mass fraction, the adsorption amount of ibuprofen on microspheres were increased. When m(PEI)∶m(CS)=1∶1, the maximum adsorption amount of ibuprofen on CP-3 (Fe3O4@CS/PEI) was determined to be 138.63 mg/g by the Langmuir adsorption equation fitting, which was twice higher than that on CP-0(Fe3O4@CS). After repeating adsorption experiments for 5 times, the microspheres still showed good adsorption performance for ibuprofen. [ABSTRACT FROM AUTHOR]

BACKGROUND: Organic matter is the most important component in shale, and organic pore is an important reservoir space of shale gas. Scanning electron microscope (SEM), the mainstream microscopic analysis and detection technology, has become an important means of shale research. The comprehensive study of organic matter is gradually becoming an important part of shale gas exploration and development. OBJECTIVES: To summarize the microscopic morphology of organic matter in organic shale of the Longmaxi Formation and discuss its hydrocarbon generation and reservoir ability according to its internal structure and composition characteristics. METHODS: The organic shale of the Longmaxi Formation in Sichuan Basin and its periphery were polished with argon ion, and the samples were examined by high resolution field emission scanning electron microscope under the condition of low voltage and close working distance. RESULTS: There were three main microscopic forms of organic matter in the organic shale of the Longmaxi Formation, which were structure-type sedimentary organic matter, differentiated symbiotic organic matter and interstitial migration organic matter. The structural sedimentary organic matter formed in the stage of sedimentation and early diagenetic evolution, and retained some biological structure characteristics or sedimentary directional structure. Differentiated symbiotic organic matter interacted with clay minerals and underwent evolutionary differentiation, forming a 'granitic structure' similar to that in magmatic rocks. On the other hand, the interstitial migration organic matter was formed in the high evolution stage of late diagenetic organic matter, and the liquid hydrocarbon filled in the intergranular of authigenic minerals, and the surrounding minerals had euhedral characteristics. The shale of the Longmaxi Formation was dominated by organic matter pores-rich interstitial migration organic matter and differentiated symbiotic organic matter, which were the high-quality gas parent materials of the Longmaxi Formation shale, with high reservoir performance. CONCLUSIONS: The research results provide deep-level micro-information for the theory of shale gas formation and the evaluation of exploration and development in the Longmaxi Formation in China. [ABSTRACT FROM AUTHOR]

In order to solve the problem of insolubility of bone powder and improve preparation process, the instant yak bone powder was prepared by liquefying yak bone with instant catapult steam explosion (ICSE), and the elemental nutrients and physicochemical properties of which were also analyzed comparing with the bone powder prepared by traditional ball-milling method.Firstly, according to the liquefaction rates of yak bone and the yields of bone powder under different pressures and maintaining times, the best ICSE condition was selected. The yields were calculated based on dry material after sieving and spray drying. Then, the physicochemical properties including the chemical structure, particle size distribution, micro-morphology, instant solubility, sedimentation, protein solubility and calcium release of yak bone powder were analyzed and compared.The results showed that the highest yield of yak bone powder was 46.16% prepared by ICSE technology under 1.5 MPa for 30 min. Therefore, the instant powder was prepared by this condition, and its nutritional components and physicochemical characteristics were analyzed. By analyzing the molecular weight distribution of peptides in liquefaction under 1.5 MPa for 30 min, it was found that bone collagen was broken into peptides with different molecular weights, and the peptides with molecular weight less than 0.5 kDa accounted for 26.14%.Also, we found that the bone microstructure treated by ICSE was looser and more porous observed by scanning electron microscope. Compared with the ball-milling yak one powder, the chemical structure of ICSE yak bone powder had no obvious change since the peak positions of Fourier infrared spectroscopy were similar. The median particle size of ICSE yak bone powder was 5.61 μm, which was significantly smaller (P <0.05) than that of ball-milling yak bone powder, and the particle size distribution was more uniform because of the regular normal distribution while the median particle size of ball-milling yak bone powder was 19.68 μm with a skewed distribution. Through the determination of basic ingredients of yak bone powder, it was found that both protein and fat contents of yak bone powder prepared by ICSE were significantly (P <0.05) higher than that of ball-milling yak bone powder while ash was less. Meanwhile, the contents of main minerals such as P, Ca, Mg, K, Zn decreased significantly (P <0.05) in ICSE yak bone powder while that of Na increased significantly. Additionally, the ICSE yak bone powder had better solubility and stability than ball-milling yak bone powder. It is soluble in water at room temperature, and no obvious precipitation occurs within 10 minutes. Comparatively, it gradually became clear and transparent with the extension of time for ball-milling yak bone powder. Besides, the protein solubility of ICSE yak bone powder increased significantly (P <0.01), which were 97.17%, 95.29%, 82.07% at 37 ℃, 60 ℃, 100 ℃ while the ball-milling yak bone powder were 4.07%, 6.47%, 10.17%, respectively. In addition, the calcium release of ICSE yak bone powder could reach 67.42 mg/g while that of ball-milling yak bone powder was only 14.25 mg/g. The ICSE method for preparing instant yak bone powder can shorten the preparation time and improve the product quality. Therefore, ICSE technology can be used as a new and efficient method to improve the value of bone byproducts. [ABSTRACT FROM AUTHOR]

BACKGROUND: When the tooth surface is treated with a rotary or manual instrument, a smudge layer is formed on the enamel and dentin by debris generated by cutting and abrasion. The bonding interface between the adhesive and the dentin is considered as a weak part in the direct repair process. To clarify the effect of smear layer on different kinds of adhesive is significantly important for dentists to select and correctly use the adhesive in clinical treatment. OBJECTIVE: To evaluate the effect of different diamond burs on the dentin bonding performance of four adhesive systems to dentin after 24 hours and 100 days of artificial saliva-storage. METHODS: Adhesive systems were: (1) VSA (Optibond Versa, Kerr); (2) AIO (Optibond All in One, Kerr); (3) SBU (Single bond Universal, 3M); (4) GLU (Bond 5, Gluma, Heraeus). In present study, 80 extracted human molars were randomly divided into four groups and each group is divided into 4 subgroups. Dentin surfaces were prepared by: (1) 600-grit SiC-paper (control group); (2) super-fine diamond bur; (3) regular diamond bur; (4) coarse diamond bur. Bonding agent was applied according to each manufacturer's instruction. After light-curing, dentin surfaces were built-up with resin composite (A2, CHARISMA, Heraeus). The micro-tensile bond strength was determined after 24 hours and 100 days of storage in artificial saliva at 37 oC. The fractured surfaces on dentin side were observed by scanning electron microscope. RESULTS AND CONCLUSION: (1) Storage for 24 hours: there was no significant difference among groups under VSA and GLU. Under SBU and AIO, the bond strength in the coarse diamond bur group was significantly lower than that in the control group (P < 0.05). Using 600-grit SiC-paper or regular diamond bur, the bond strength showed no significant difference only between AIO and VSA groups. Using regular diamond bur, the bond strength showed no significant difference in the VSA group compared with the AIO, GLU and SBU groups (P > 0.05). Using coarse diamond bur, the bond strength in the VSA group had significant difference compared with the AIO, GLU and SBU groups (P < 0.05), and other groups had no significant difference (P > 0.05). (2) Storage for 100 days, there was no significant difference among groups under VSA and GLU. Under SBU, the bond strength in the coarse diamond bur group was significantly lower than that in the control group (P < 0.05). Using 600-grit SiC-paper, the bond strength showed no significant difference only between VSA and SBU groups (P > 0.05). Using regular diamond bur, the bond strength showed no significant difference in the GLU group compared with the SBU, and VSA groups (P > 0.05). Using coarse diamond bur, the bond strength had no significant difference between VSA and AIO groups (P < 0.05). (3) Using VSA, the bond strength in each group at 100 days showed significant difference compared with that at 24 hours (P < 0.05). (4)Compared with immersed for 24 hours, the ratio of bond interface and combined crack in the VSA, SBU and GLU groups after immersed for 100 days was increased, especially the VSA group. Compared with the other groups, the ratio of bond interface and combined crack in the GLU group after immersed for 24 hours and 100 days both increased by 50%. (5) These results indicate that preparation by different burs produces different smear layers, which has significant effect to self-etching adhesive system and has no significant effect to total-etching adhesive system. Storage time makes effect on different adhesives. [ABSTRACT FROM AUTHOR]

A tough, porous silk fibroin (SF)/polyethylene glycol (PEG) cryogel was prepared through a simple freezethawing procedure by using PEG as cross-linking agent. Fourier-transform infrared (FT-IR) spectra, scanning electron microscope (SEM) and universal-testing machine were used to investigate the conformational change, micromorphology, mechanical properties, and swelling behaviors of cryogels. Results demonstrated that the incorporation of PEG faclitated the formation of crystal structures of SF chains, and the microstructure and mechanical properties can be tailored by freezing temperature, mass ratio of PEG to SF (mPEG/mSF), and SF mass fraction. When freezing temperature was −20 °C, wSF = 0.16, and mPEG/mSF = 0.50, the compressive modulus of the SF/PEG cyrogels was up to 0.44 MPa and can tolerant large compressive strain (90%) without permanent deformation and fracture. The cryogel also demonstrated excellent elasticity recovery during cyclic compression test, and the Young’s modulus and toughness of cryogels could reach up to 4.15 MPa and 680.81 kJ/m3, respectively. The cryogels with homogeneously distributed inter-connected porous structure would promote their potential applications in tissue engineering field. [ABSTRACT FROM AUTHOR]

【Objective】In order to provide a new approach and theoretical basis for the utilization of fish scale waste,the preparation and structure change of fish scale polypeptide chelate iron was studied.【Method】The grass carp fish scale polypeptide and ferrous chloride were used as the raw material. The iron chelate was obtained by optimizing chelation conditions. The structure of fish scale polypeptide and iron-polypeptide chelates was characterized by elemental analysis, ultraviolet, infrared, electron microscope scanning and X diffraction analysis. 【Result】The antioxidant was ascorbic acid, the mass ratio of ascorbic acid to ferrite was 0.15∶1, the mass ratio of polypeptide to ferrous salt was 2∶1, pH value was 5, reaction time was 40 min and reaction temperature was 30 ℃. Under the optimal chelating conditions, the chelated rate was 83.4 %. The absorption peak of NH2 in the characteristic region of infrared spectroscopy shifted from 3301.42 cm-1 to 3362.61 cm-1, resulting in obvious displacement. Elemental analysis showed that the iron content in the chelate was 10.625 %, and the content of N, C and H decreased significantly. Scanning electron microscopy showed that the chelated particles changed from spherical hollow structure to dense grains. X-ray diffraction patterns showed that the crystallinity of the chelate increased significantly. 【Conclusion】According to the above conditions, the chelation rate of peptide ferrous chelate is high, and the coordination between ferrous ion and peptide is obvious. [ABSTRACT FROM AUTHOR]

BACKGROUND: Our previous studies have found that silk fibroin-chitosan scaffold carrying bone marrow mesenchymal stem cells can repair cartilage defect in rabbits, but further exploration on the biocompatibility of tissue engineered cartilage is yet to be done. OBJECTIVE: To explore the biocompatibility of tissue engineered cartilage that is constructed in vitro by silk fibroin-chitosan scaffold with bone marrow mesenchymal stem cells. METHODS: Three-dimensional silk fibroin-chitosan scaffolds were prepared in a ratio of 1:1. Rabbit bone marrow mesenchymal stem cells were extracted, induced and seeded onto the silk fibroin-chitosan scaffold to construct the cell-scaffold composite. The composite was then implanted into a rabbit joint defect model for cartilage repair. There were three groups in the present study: experiment group with implantation of induced bone marrow mesenchymal stem cells+silk fibroin-chitosan scaffold into the cartilage defect model, control group with implantation of silk fibroin-chitosan scaffold into the cartilage defect model, and blank group without implantation. RESULTS AND CONCLUSION: The three-dimensional silk fibroin-chitosan scaffolds were successfully prepared and combined with bone marrow mesenchymal stem cells (BMSCs) to construct the tissue engineered cartilage for repair cartilage defects in rabbits. Blood routine parameters, procalcitonin levels, erythrocyte sedimentation rates and C-reactive protein levels detected at 2, 4, 8, and 12 weeks post-implantation indicated no obvious signs of systemic infection, and there was no damage to liver and kidney functions in the three groups. There were also no significant differences between the three groups in terms of blood routines and liver and kidney functions (P > 0.05). As shown by gross observation, hematoxylin-eosin staining and scanning electron microscope, in the experimental group, cartilage defects were repaired, with scaffold degradation, no presence of inflammatory cells, and good integration with surrounding tissues. Therefore, tissue engineered cartilage constructed in vitro by silk fibroin-chitosan scaffolds carrying bone marrow mesenchymal stem cells has good biocompatibility, which provides an experimental basis for tissue engineering approaches to cartilage repair. [ABSTRACT FROM AUTHOR]

In order to reduce the sensitivity of 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane（ CL-20）, CL-20/1,3,5-triamino-2,4,6-trinitrobenzene（ TATB） energetic composites were prepared by using one-step ball milling method. The properties of raw materials and energetic composites were characterized by using scanning electron microscope, X-ray diffractometer, infrared spectrometer and diffrential scanning calorimetery. The impact sensitivity test was carried out. The results show that the as-prepared product is not a simple physical mixture of CL-20 and TATB, but a new crystalline phase is formed. In the SEM pattern, compared with the raw materials, the morphology of CL-20/TATB composite is regular spherical or ellipsoidal, and the particle size is in the range of 50-200 nm. In the XRD pattern, the main diffraction peak in the final product is obviously different from the main diffraction peaks in the raw CL-20 and the raw TATB. New XRD diffraction peaks arise, which indicates that a new crystal form appears in the final product. The diffraction peak become wider due to the decrease in particle size.In FT-IR pattern, the position of characteristic vibration peak of the functional group in the CL-20/TATB composite is shifted due to the hydrogen bond between CL-20（ —NO2 or —CH） and TATB（ —NO2 or—NH2）. In the DSC curve, compared with raw CL-20 and raw TATB, the exothermic peak of the CL-20/TATB composite is advanced, which indicates that the thermal decomposition activity of CL-20/TATB composite is stronger than those of raw CL-20 and raw TATB. In the impact sensitivity test, the characteristic height of CL-20/TATB composite is 62 cm higher than that of CL-20, indicating that the impact safety of CL-20/TATB is better than that of CL-20. [ABSTRACT FROM AUTHOR]

Iron powder was used as passivator to analyze the adsorption characteristics of iron powder for Cd(Ⅱ) under various key factors through adsorption experiment. The process of Cd(Ⅱ) adsorption by iron powder was investigated through adsorption isotherm and adsorption kinetic models. By scanning electron microscope (SEM) photographs and X-ray diffraction (XRD) spectra, the adsorption mechanism was explored. The experimental results show that unit adsorption amount of iron powder is increased with the increasing of initial solution concentration level and reaction time and is decreased with the increasing of dosage. The initial solution pH has little effect on Cd(Ⅱ) adsorption by iron powder. When the initial solution concentration is 100 mg·L-1 with dosage of 20 g·L-1 and reaction time of 48 h, the removal efficiency of Cd(Ⅱ) is 94% with equilibrium adsorption capacity of 4.69 mg·g-1. Langmuir isotherm, Freundlich isotherm, R-P isotherm and intraparticle diffusion model are consistent with the adsorption process. Mechanism discussion shows that the removal of Cd(Ⅱ) is mostly pushed by the combination of physical adsorption and chemical adsorption by iron powder, while the chemical adsorption is dominant. The specific means include reduction of Cd(Ⅱ) by iron powder, coprecipitation of iron-containing colloid with Cd(Ⅱ) and electrostatic interaction. [ABSTRACT FROM AUTHOR]

The microstructure， mechanical properties and hydrogen-induced cracking resistance of high strength steel used for flexible riser after different heat treatments were studied by means of optical microscope(OM)， scanning electron microscope(SEM)， transmission electron microscope(TEM) and electron back-scattered diffraction(EBSD). The results show that compared with the traditional quenching and tempering treatment， multi-stage heat treatment can refine the microstructure， promote the dispersion of fine precipitates and increase the density of grain boundary so that the strength of the tested steel can be improved greatly. Moreover， since multi-stage heat treatment increases the number of hydrogen traps， reduces the size of precipitates and improves the distribution of hydrogen traps and the hydrogen solubility， the hydrogen-induced cracking resistance of the tested steel is also improved. [ABSTRACT FROM AUTHOR]

BACKGROUND: Cartilage-derived extracellular matrix as a natural material provides an ideal microenvironment for cells that depend on tissue growth and has become an ideal scaffold material for cartilage repair. OBJECTIVE: To prepare human articular cartilage-derived extracellular matrix as a cartilage tissue engineering scaffold and to evaluate its physicochemical properties and biological properties. METHODS: The human articular cartilage tissue was collected, pulverized into homogenate, decellularized, and freeze-dried to prepare a cartilage tissue engineering scaffold. Scaffold morphology was observed under scanning electron microscope. The porosity and water absorption and mechanical properties of the cartilage tissue engineering scaffold were determined. The composition of tissue engineering scaffold was observed by histochemistry and immunohistochemistry. Rabbit chondrocytes were cultured with the leaching liquor of human cartilage-derived extracellular matrix tissue engineering scaffold for different time periods. Routine cell culture fluid was used as control. The cytotoxicity of tissue engineering scaffold was detected by MTT colorimetry. Human chondrocytes and tissue engineering scaffold were co-cultured and cell adhesion and proliferation were observed under the scanning electron microscope and confocal microscope. The cell-scaffold complex sections were stained by histochemistry and immunohistochemistry. RESULTS AND CONCLUSION: The prepared scaffold had three-dimensional porous sponge-like longitudinally oriented structure. There were cartilage fibers around the scaffold pores. After hematoxylin-eosin staining, no nucleus was observed. Both safranin O and Sirius red staining confirmed that cartilage tissue engineering scaffold contained collagen and cartilage matrix. The porosity and water absorption of the scaffold was (91.8±2.9)% and (93.5±1.4)%, respectively. MTT results showed that the leaching liquor of human cartilage-derived extracellular matrix was non-toxic to chondrocytes. After co-culture, human chondrocytes adhered, proliferated and evenly distributed on the peripheral wall of the scaffold pores. The results showed that human articular cartilage-derived extracellular matrix had similar composition to natural cartilage, provided the structure suitable for cell adhesion and proliferation, and exhibited good histocompatibility. Therefore, human articular cartilage-derived extracellular matrix can be used as a scaffold material for repairing cartilage defects by tissue engineering technique. [ABSTRACT FROM AUTHOR]

To prepare the cassava starch-based potassium releasing superabsorbent polymer (AM-SAP), an orthogonal experiment and range analysis were applied to optimize the synthesis conditions for the best water absorbency and potassium release capacity. A comprehensive feasibility study on the potassium release amount and release rate by activated muscovite (AM) sample was investigated as a function of cosolvent dosage, reaction temperature and reaction time. The water absorbency, repeated water absorbency, water holding capacity, water absorption swelling process and cumulative potassium release amount of AM-SAP samples were all compared with different AM dosages. The structural and morphological characteristics of the raw muscovite (RM), AM and AM-SAP samples were compared by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscope analysis (SEM). The results showed that the RM samples were best activated as reaction temperature and time of 950 ℃ and 2 h, respectively, with the mass ratio of NaCl and muscovite was 2:1. Under such condition, the potassium release amount and release rate could reach by 92% and 32.4 mg/g, respectively. The maximum water absorbency of AM-SAP sample was 358 g/g in the distilled water and 155 g/g in the tap water, respectively, which was determined as the starch content, crosslinking agent, initiator, acrylamide and neutralization degree were 20%, 0.02%, 0.4%, 25% and 80%, respectively. The AM amount, that affected the water absorption and potassium release capacity of AM-SAP sample were quite different. Compared with the pure cassava starch-based superabsorbent polymer, the repeated water absorbency of AM-SAP sample was obviously larger than that of the former with the AM amount of 20%. While the cumulative potassium release amount of AM-SAP sample was increased with the increasing of AM dosage. After 9 d immersion at the temperature of 25 ℃, the cumulative potassium release amount and release rate were increased by 2.59 and 3.64 times, respectively. The AM-SAP sample could maintain more than 40% of the initial water content after 25 h later, even at the temperature of 40 ℃. The swelling process of AM-SAP sample conformed to the non-Fickian diffusion, which was determined by the diffusion of water molecules and the relaxation process of polymer chain segments. The FTIR data confirmed that AM existed in the AM-SAP in the form of physical filling, and some powder reacted with organic matter in the process of polymerization. The SEM showed that the rough surface of the AM-SAP sample was beneficial to the performance of water absorption and potassium release. It was preliminarily concluded that the AM-SAP is expected to be widely used in agricultural production due to its capacities of water retention, repeated water absorption and slow releasing and promotion of potassium. [ABSTRACT FROM AUTHOR]

Herein, a comprehensive experiment was developed based on the fabrication and characterization of highmolecular- weight silk peptide functionalized graphene nanosheets (SP-Gr) and its application in electrochemical sensing of dopamine. In this experiment, transmission electron microscope, scanning electron microscope, X-ray photoelectron spectroscopy, X-ray diffraction and UV-Vis spectroscopy were used to characterize SP-Gr nanocomposites. SP-Gr nanocomposites were coated onto a glassy carbon electrode surface to fabricate an electrochemical sensor for determining dopamine. Experimental conditions for dopamine determination were optimized. An effective method was developed for determining dopamine. [ABSTRACT FROM AUTHOR]

The core observation and casting thin section authentication, combined with physical properties, scanning electron microscope, X-ray diffraction and mercury intrusion experiment, were employed to characterize the controlling factors on physical properties of Cretaceous Nahr Umr Formation sandstone reservoir in Halfaya oilfield. Iraq. The results show that the tide-controlled deltaic sandstone reservoir of core B of Nahr Umr Formation in Halfaya oilfield has medium porosity and permeability, and the reservoir space includes intergranular pore and dissolved pore; the pore throat changes greatly and the heterogeneity is strong; the controlling factors of reservoir physical properties include sedimentation and diagenesis; sedimentation affects pore space type and pore structure; reservoirs with good physical properties are developed with strong hydrodynamic conditions and good rock composition; diagenesis plays a significant role on the physical properties of reservoir; the compaction and cementation cause a large amount of pore filling, and the authigenic and clay minerals not only reduce the pore space, but also cause blockage of the throat, resulting in plugging of the pore throat and deterioration of the physical properties; the secondary pores produced by dissolution improve the reservoir physical properties; the highest-quality reservoir develops at the cross-laminated sandstone in tide-controlled distributary channel facies, and has the characteristics of large grain size, well sorting, relatively high content of quartz, low contents of clay mineral and cement, and large size of pore throat; the corresponding porosity and permeability are medium-high and high respectively, which are the focus of characterization and modeling of reservoir in the research area. [ABSTRACT FROM AUTHOR]

In order to improve the decomposition performance and dispersibility of ammonium perchlorate (AP), the crude lead ferrocyanide (Pb2Fe(CN)6) was synthesized by using the coordination precipitation method, and the nanometer-scale particles were pulverized by using a vertical stirring ball mill. Ultrafine Pb2Fe(CN)6/AP composite particles were prepared by using direct grinding method, ultrasonic assisted method and solvent-nonsolvent method. The morphology, particle size, crystal structure and thermal decomposition performance of the prepared composite particles are characterized by using scanning electron microscope, dry laser granulometer, X-ray diffractometer, infrared spectrometer and differential scanning calorimetry. The morphology of composite particles synthesized by solvent-nonsolvent method is quasi-spherical, the particle size is about 8 μm, the dispersion is relatively uniform, and the coating effect is better. Compared with pure AP, the pyrolysis temperatures of the composite particles prepared by direct grinding method, the ultrasonic assisted method and the solvent non-solvent method are reduced from 446.3 °C to 390.4 °C,391.2 °Cand 379.1 °C, respectively. The activation energy of pyrolysis is reduced by 14.2%, and the rate constant k is increased by 28.6 times. The combination of AP and Pb2Fe(CN)6 can effectively prevent AP agglomeration, meanwhile, the apparent bulk density is increased by 6.16%，and the tap density is increased by 10.4%. [ABSTRACT FROM AUTHOR]

Firstly, the copolymer poly[(N-isopropyl acrylamide)-co-(N-(2-hydroxyethyl)acrylamide)] (P(NIPAM-co- HEAA)) was obtained by reversible addition fragmentation chain transfer (RAFT) polymerization reaction at different feed ratio of NIPAM/HEAA. Then, the double bond functionalized copolymer poly[(N-isopropyl acrylamide)-co-(2- acrylamidoethyl acrylate)] (P(NIPAM-co-AAEA)) was obtained by coupling with acryloyl chloride. Finally, thermo-sensitive hydrogel coating was fabricated by ‘one step ’ photocrosslinking reaction of thermo-sensitive copolymer P(NIPAM-co- AAEA) and double bond functionalized antibacterial peptides (AMPs) on polydimethylsiloxane (PDMS). The thermosensitive copolymers were characterized by proton nuclear magnetic resonance (1H-NMR) to identify the ratio of polymeric monomers. The AMPs were identified by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS). Then, the modification of the hydrogel on the substrate and the morphology were characterized by fourier transform infrared spectroscopy (FT-IR) and scanning electron microscope (SEM), respectively. The thermosensitivity of the hydrogel coatings were confirmed by static water contact angle (WCA) as a function of temperature variation. Finally, the antifouling and antibacterial properties of the hydrogel coating were validated by bacterial LIVE/DEAD viability assays characterized by Confocal Laser Scanning Microscope (CLSM) and colony counting assays. The results showed that when the feed ratio of NIPAM/HEAA was controlled at the optimized value of 87:13, the LCST of P(NIPAMco- AAEA) was determined as 36.6 °C, which was close to human body temperature 37 °C. It is expected that these copolymers would present a thermo responsiveness under body temperature. Meanwhile, the prepared thermo-sensitive hydrogel coating exhibited expeted antifouling property and antibacterial activity. [ABSTRACT FROM AUTHOR]

Recycled aggregate concrete has obtained worldwide attention as an important part of sustainability. In the aspect of durability of recycled concrete under coupling multi-factors, a number of devices were designed and installed to investigate the durability of recycled concrete. In previous studies, the concrete specimen was tightened by the screws to apply a prestress with the jack, and then specimen was put in the devices for the durability test, which was difficult to operate and prone to stress loss. In this paper, in order to better research the durability of concrete under coupling multi-factors, we designed a coupling mechanism of alternated with loading and freeze-thaw cycles in salt-solution to replace the traditional mold loading to accurately simulate the simultaneous interaction of freezing thawing, corrosion and load. The coupling protocol was designed with repetitive load and 25 time’s freeze-thaw cycles alternately 2 times in the salt-solution, in which the maximum stress level (the applied stress to 28 days compressive strength) of repetitive load is 0, 40%, 70%. The specific operation was that specimens were loaded repetitively for the first time, then they were freeze-thawed in the salt-solution for 25 time’s cycles, after that, they were repetitively loaded again, and freeze-thawed in the salt-solution for another 25 time’s cycles. The experiment on compressive strength and microhardness of recycled concrete and natural concrete under coupling action was carried out. In the macroscopic test, compressive strength loss of each specimen was measured under the above mentioned coupling protocols. At the same time, the microhardness across the ITZs between the coarse aggregate and the cement matrix was measured before and after 50 freeze-thawing cycles for the control specimens. The macro test results showed that the stress level of the coupling action increased from 40% to 70%, the compressive strength loss of both recycled concrete and natural concrete increased from 1.8% and 71.3% to 27.2% and 100% respectively. It is implied that the durability of recycled concrete under coupling action is better than that of natural concrete, and the loading mechanism with high stress level will accelerate the deterioration of both recycled concrete and natural concrete. The micro test results showed that the microhardness values gradually increased with the increases of distance from the interface of natural aggregate and cement paste, the microhardness losses were 8.1% and 23.8% of the interface of both recycled aggregate and natural aggregate before and after the coupling action respectively. It can be seen that the interface transition zone was the weakest part of the concrete, and the decreasing rate of microhardness of the interface transition zone in natural aggregate specimens was faster than that of recycled aggregate after 50 time’s freeze-thaw cycles in salt-solution. The environmental scanning electron microscope (ESEM) test results indicated that the bond strength and plastic deformation ability of interface of natural aggregate are better than that of recycled aggregate before freeze-thaw cycles, while the ability to resist freeze-thaw at the interface transition zone of recycled aggregate was better than natural aggregate after freeze-thaw cycles. The related results can provide an insight into the long-term performance of recycled concrete subjected to harsh environmental conditions and thus to promote practical application of recycled aggregate concrete in the future. [ABSTRACT FROM AUTHOR]

This paper applied 60 mesh, 80 mesh, 100 mesh quartz sands to make five kinds of sandy soil, utilized laser particle size meter and scanning electron microscope to obtain cumulative percentage of particle size and 135 SEM (scanning electron microscope) images of soil section, used volume fractal formula and PCAS to analyze particle size and SEM images, respectively. Results show that ranges of values about volume fractal dimension of sandy soil are 2. 093 77 ~2. 294 96, 1. 298 7 ~2. 194 25, 2. 014 9 ~2. 280 15 μm, respectively, at 0. 8 to 1 000 micron, 50 to 500 micron, 0. 8 to 50 micron. The pore fractal dimension and porosity of sand are 1.117 9 ~1.133 9 and 0 . 519 4 ~ 0 . 597 2, respectively. The larger the volume fractal dimension is, the better the particle gradation is. Apart from that particle size is the affected factor towards pore fractal dimension, particle size distribution also impacts pore fractal dimension of sandy soil, and the better the particle gradation is, the larger the fractal dimension of pore is. Compared with the particle size of sandy soil, particle gradation is the main factor affecting the porosity of sandy soil. The worse the particle gradation is, the greater the porosity of sandy soil is. [ABSTRACT FROM AUTHOR]

In this work， the characterization of process mineralogy of the gold ore from Baolun gold mine was studied through chemical analysis， X-ray diffraction， optical microscope and scanning electron microscope analysis. That can provide a theoretical basis and guideline to select ore dressing process. The results show that the Au and S contents of the ore are 10.1g·t-1 and 0.65%， respectively， and the main gangue minerals are quartz and muscovite. The gold minerals in the ore are mainly native gold with the relative content of 90.58%. The particle size range of gold mineral is wide， and the contents of giant-grained gold(>300μm)， coarse-grained gold(74~300μm)， medium-grained gold(37~74μm)， fine-grained gold(10~37μm)and micro-grained gold(0.10~10μm)are 3.84%， 28.85%， 18.04%， 23.52% and 25.75%， respectively. The occurrence state of gold minerals in the ore is wrapped by gold， intergranular gold and fissure gold， the content of which accounts for 48.37%， 43.24% and 8.39%， respectively. Based on the researches of process mineralogy， a Knelson gravity separation-flotation technology cooperated with multi-stage grinding process is proposed. [ABSTRACT FROM AUTHOR]

Objective: To obtain the sequence of PU3 gene from the oyster Pinctada fiicata and study the function in biomineralization. Methods: The frill length of PU3 gene was obtained by RACE. The expression levels of PU3 gene in different tissues were detected by real-time fluorescent quantitative PC'R. The expression of PU3 gene through the shell notching experiment was detected by real-time fluorescent quantitative PC'R. RNAi experiments was used to inhibit the expression of PU3 gene, and then the change in the surface of the shell of was obseived by the scanning electron microscope. Results: The frill-length cDNA of PU3 gene from Pinctada fiicata is 2361 bp. encoding 618 amino acids. Functional domain analysis indicated that it contained four FN3 domains. PI]3 is highly expressed in the mantle membrane, especially in the edge of mantle membrane, hi the process of shell repairing, the expression level of PU3 gene showed an increasing trend. After using RNAi technology to inhibit the expression of PU3 gene, the prismatic layer of the shell has changed, the gaps became wider, and voids appeared. Conclusions: It is speculated that PU3 gene acts as a positive regulator in the process of biomineralization, and mainly influences the prismatic layer of the shell. Inhibiting its expression will affect the framework structure of the prism layer. [ABSTRACT FROM AUTHOR]

Cellulose nanofibers （CNFs） and cellulose diacetate （CDA） are mixed by solvent substitution method using dimethyl sulfoxide/trichloromethane as a new two-component solvent system. Cellular carbon fiber （CF）/Polylactic acid （PLA） composite supports are directly printed by fused deposition modeling （FDM）3D printing technology on parallel conductive plates. CNFs/CDA composite nanofibrous composite membrane devices based on 3D printing technology are fabricated by directly depositing CNFs/CDA composite nanofibrous composite membranes on CF/PLA composite supports using electrospinning technology. The morphology and structure of the prepared CNFs/CDA composite nanofibrous composite membranes are characterized by transmission electron microscope （TEM），scanning electron microscope （SEM），Fourier transform infrared spectroscopy （FTIR） and X - ray photoelectron spectroscopy（XPS）. And the adsorption performance of the CNFs/CDA composite membrane devices on protein is determined. The results show that when the content of CNFs is 0.5%（in mass），the average diameter of the CNFs/CDA composite nanofibers is up to（381±116）nm，and the diameter distribution of nanofibers is more uniform， and the diameter of more than 80% nanofibers is in the range of 200—500 nm. In addition，the CNFs/CDA nanofibrous composite membrane devices based on 3D printing technology have good adsorption capacity for bovine serum albumin（BSA），with the maximum adsorption capacity of 433.89 mg/g. [ABSTRACT FROM AUTHOR]

A 15% lambda-cyhalothrin microcapsule suspension of polyurea resin was prepared as a capsule material by interfacial polymerization. In the preparation of lambda-cyhalothrin microcapsule suspension, the initial oil-water ratio (Ri) was obtained by the quotient of the weight of the oil phase and the weight of the initial water. The effect of the Ri value on the physico-chemical properties of the lambda-cyhalothrin microcapsule suspension was also investigated. Four 15% lambda-cyhalothrin microcapsule suspensions treated with different initial oil-water ratios were prepared. Their Ri values were 1 : 0.55, 1 : 0.69, 1 : 0.83 and 1 : 0.97, respectively. The morphology of the microcapsules was characterized by optical microscope (OM), scanning electron microscope (SEM) and laser particle size analyzer. The encapsulation efficiency and storage stability of each treatment were determined. The experimental results showed that, when the Ri values were 1 : 0.83 and 1 : 0.97, the 15% lambdacyhalothrin microcapsule suspension had high capsule quality, good microcapsule morphology, and the microcapsule encapsulation efficiency was 90% or higher. The particle sizes were in the range of 3-4 μm (D95), and the storage stability has also be qualified. This study has provided a reference for the preparation of lambda-cyhalothrin microcapsule suspensions. [ABSTRACT FROM AUTHOR]

In order to obtain the influence of coating layers on the properties of nano-aluminum powders, the nano-aluminum powders prepared by the electric explosion method are coated with 5%, 10% and 15% of fluororubber. The surface morphologies, coating thicknesses, specific surface areas, elemental valence states and thermal responses of modified nano-aluminum powders are characterized using scanning electron microscope, transmission electron microscope, physical adsorption analyzer, X-ray photoelectron spectrometer and simultaneous thermal analyzer. And the active aluminum contents and combustion heat of different samples were measured. The results show that the specific surface areas of the modified nano-aluminum powders are slightly large than that of the passivated nano-aluminum powders. Fluororubber coatings chemically adsorb on the surface of nano-aluminum powders, which enhances the thermal stability of nano-aluminum powders, prevents the aluminum powders from further oxidation, and makes one of the contents of active aluminum up to 85.85%. The fluororubber promotes the combustion of modified nano-aluminum powders, so that the combustion heat of the modified nano-aluminum powders is more than that of the passivated nano-aluminum powders. [ABSTRACT FROM AUTHOR]

BACKGROUND: The Xichuan turquoise mining area in Henan Province belongs to the east extension of the turquoise metallogenic belt in the junction of Hubei and Shaanxi Provinces. A lot of turquoise artifacts have been excavated in many early archaeological sites near Xichuan. Therefore, the distribution of the Xichuan turquoises has attracted wide attention of many archaeologists. OBJECTIVES:To study mineralogical characteristics of Xichuan turquoise in order to improve the mineralogical study of turquoise in different mining areas in China and provide important data support for tracing the mineral resources of early turquoise artifacts in China. METHODS: Technologies including Polarizing Microscope, Scanning Electron Microscope, X-ray Diffraction Spectrometry were applied to study the texture and structure of turquoise. Electron Probe Microanalysis and Back Scattered Electron Imaging were applied to study the mineral assemblage of Xichuan turquoise. RESULTS: Xichuan turquoise, ring-like, nodular and patchy granular was primarily composed of fine scaly, short columnar and lamellar microcrystalline aggregates. By comparing the microcrystalline structures of different samples, it was noted that the sizes, shapes and distributions could affect the densification and color of Xichuan turquoise. Quartz, chalcedony and iron oxide were common in the Xichuan turquoise aggregate. Svanbergite could also be observed in some samples. CONCLUSIONS: By comparing the mineral assemblages of turquoise in other mining areas, it was found that Xichuan turquoise was similar to the turquoise in Hubei Province with quartz and limonite as main mineral impurities, different from the turquoise in Anhui Province with kaolinite as main mineral impurities. [ABSTRACT FROM AUTHOR]

In order to solve the decrease in the reactivity of nano-aluminum powder due to the alumina shell on its surface, the nano-aluminum powders were directly encapsulated by polyvinyl alcohol (PVA)during electrical explosion of wires. The apparent morphology of sample was detected by scanning electron microscope (SEM) and transmission electron microscope (TEM), and the particle size distribution was characterized by dynamic laser light scattering particle size analyzer. The valence states of surface elements were analyzed by X-ray photoelectron spectroscope, and the thermal behaviours of micrometer Al, nanometer Al and products were compared by simultaneous thermal analyzer. The combustion heat was measured according to relevant national military standards, and active Al content was measured using NaOH exhaust method. The results show that the average size of coated sample is nearly 200 nm, and the particles form a multi-core structure. The active Al content reaches 84. 27% which is 22% higher than that of ordinary nano-Al particles. It was proved that PVA effectively relieves oxidation of nano-Al. The coated products have low onset temperature of oxidation (548. 6 °C) and can release energy more rapidly compared to micro-Al. The in-situ coated sub-micro Al has high active reactivity and quick energy release rate. [ABSTRACT FROM AUTHOR]

In order to improve the reusable performance of nano-silver in catalytic reduction of p-nitrophenol, polyvinyl alcohol sponge (PVA-S) loaded with nano-silver particles (PVA-S-Ag) was prepared. Scanning electron microscope (SEM), Fourier transform infrared spectra (FT-IR) and X-ray diffraction (XRD) were used to characterize the structure of PVA-S-Ag. The effect of the catalytic reduction of p-nitrophenol by PVA-S-Ag in the presence of sodium borohvdride was investigated by UV-vis. The results show that PVA-S-Ag is an excellent catalyst for the reduction of p-nitrophenol. Resides, PVA-S-Ag still maintains good catalytic reduction effect on 4-NP after several cycles. [ABSTRACT FROM AUTHOR]

Combined with scientific research, a comprehensive chemical experiment of “ Preparation and Characterization of Photo-responsive Supramolecular Gel” was designed. The photo-responsive gel was constructed by two components co-assembly of spiropyran and gelling agent, and its properties were characterized. The results show that the system exhibits good photo-responsive property under light with different wavelengths. The changes in the molecular structure of spiropyran lead to its photochromism, which has good reversibility. The corresponding changes in the UV spectra and scanning electron microscope images have taken place. Through the experiment, students’ interests in scientific research were stimulated, and students’ innovative thinking and comprehensive quality were improved. [ABSTRACT FROM AUTHOR]

The core observation, casting and fluorescence thin section authentication, combined with confocal laser scanning microscope(CLSM), scanning electron microscope(SEM), X-ray diffraction and rate-controlled mercury intrusion, were employed to characterize tight oil reservoir space properties of Permain Lucaogou Formation in Jimusar sag of Junggar Basin, China, aiming at analyzing the diagenesis, reservoir space and relationship between them. The results show that tight oil reservoir of Lucaogou Formation in Jimusar sag is mainly composed of carbonate, terrigenous detrital, pyroclastic and normal mixed sedimentary rocks, and the reservoir spaces include secondary solution pores, intercrystalline pores and microcracks; the different types of rock undergo different diagenesis processes and develop different reservoir spaces. ①In the carbonate rocks, micritic dolostones are characterized by single component, severe compaction and weak cementation, and the reservoir space is dominated by dolomite intercrystalline pores; with the increasing of silty and tuffaceous contents, the silty arenites and tuffaceous dolostones are characterized by weaker compaction, stronger dissolution and cementation, and the reservoir space is mainly composed of feldspar inner pores, mold holes and tuffaceous dissolution pores. ②In the terrigenous detrital rocks, tuffaceous siltstones are characterized by moderate compaction, and widespread dissolution of feldspar and dispersive tuffaceous, the dissolution pores are filled by a great amount of clay mineral, and the reservoir space is mainly composed of honeycomb feldspar dissolution pores and tuffaceous dissolution pores; the dolomitic mudstones are characterized by strong compaction and poor dissolution, and intercrystalline pores and microcracks can be observed in it. ③In pyroclastic rocks, the characteristics of silty and dolomitic tuffites are similar to those of tuffaceous siltstones, but the kinds of cement are a lot, the main reservoir spaces are secondary dissolution pore with a few intercrystalline pores. [ABSTRACT FROM AUTHOR]

In order to explore the method of preparing green adsorption material from agricultural biomass to treat waste-water containing Cd2+, the banana peel was modified by NaOH to adsorb Cd2+. The condition of modification and adsorption process were discussed through static adsorption experiment combined with isotherm (involve Langmuir, Freundlich, Temkin and D-R) and kinetics models (involve First-order, Pseudo Second-order, Elovich and Intraparticle diffusion). The surface structure and properties were characterized by using Brunauer-Emmett-Teller (BET) surface area and pore size analysis, scanning electron microscope (SEM), energy dispersive spectrometer (EDS), element analyzer (EA) and Fourier transform infrared spectrometer (FTIR), which were used to explore the mechanism of modification and adsorption. The results of optimized modification conditions showed that NaOH was 0.25 mol/L, modification time was 30 min. Static adsorption experiment showed that adsorption capacity of modified banana peel reached 87.15 mg/g and the Equilibrium time reached 45 min. The results showed that under the same conditions, the dosage of 4 g/L and the pH value of 6 were better than those of unmodified banana peel (adsorption capacity = 37.61 mg/g, equilibrium time = 60 min). BET specific surface area and pore size analysis confirmed that the specific surface area and total pore volume increased 108 times and 3.6 times respectively after modification. Scanning electron microscopy showed that the surface became uneven and wrinkled after modification. The changes mentioned above were conducive for Cd2+ to enter the interior of the material along through diffusion，thus contacting and reacting fully with adsorbent. According to the change of element composition, the H/C ratio of the modified banana peel decreased from 0.158 to 0.102, while the K content decreased by 4.38 percentage points, while the Na content increased by 1.55 percentage points after the modification, indicating the exchange reaction between K and Na. Furthermore, FTIR denoted active functional groups such as O-H (3 320 cm-1), C-H (2 910 cm-1), C=O (1 600 cm-1), C-C (1 390 cm-1), C-O (1 020 cm-1) were found on the surfaces of banana peel whether modified or not, indicated good adsorption potential for Cd2+. The results showed that the isothermal adsorption and adsorption kinetics of banana peel under different modification conditions were described by Langmuir isotherm model and pseudo-second order model, respectively. The results showed that Cd2+ ions were adsorbed by unmodified and modified banana peel through a single layer membrane, and the mechanism of Cd2+ was complex interaction of physical and chemical factors. Freundlich, D-R isotherm model and Elovich kinetic fitting results showed that banana peel had a strong affinity for Cd2+and the adsorption capacity was enhanced after modification. Combined with characterization and model analysis, it was concluded that the adsorptive mechanism of raw banana for Cd2+ was multiple, including ion exchange/ligand exchange, cation-π and electrostatic interaction, while the adsorptive mechanism of modified banana peel for Cd2+ was ion exchange. The results showed that NaOH modified banana peel had good adsorbability for Cd2+ in aqueous solution. This conclusion will provide an important theoretical basis for the preparation of environmental friendly adsorbents from lignocellulose biomass to remove heavy metals from polluted water. [ABSTRACT FROM AUTHOR]

p-Chloroaniline modified carbon nanotube film(pca-CNT)was prepared by diazotization reaction of carbon nanotube(CNT)film.Poly(2,5-dihydroxy-1,4-benzoquinonyl sulfide)(PDBS)was grown uniformly on the the surface of pca-CNT by in situ polycondensation method.The obtained pca-CNT@PDBS composite was used as flexible electrode later.The morphology and structure of composite was characterized by field scanning electron microscope(FE-SEM),field transmission electron microscope(TEM),energy dispersive spectrum(EDS),Fourier infrared spectrum(FI-IR)and photoelectron spectroscopy(XPS).The results indicated that PDBS was coated on the pca-CNT film successfully.The electrochemical testing showed that the pca-CNT@PDBS flexible electrode exhibited an area specific capacitance(CA)of 108 mF/cm2 at the current density of 1 mA/cm2,higher than pure PDBS(65.6 mF/cm2)and CNT-supported PDBS(CNT@PDBS,83.2 mF/cm2).With the pca-CNT@PDBS and CNT@PDBS as flexible positive electrode respectively,CNT-supported poly(1,5-diamino-anthraquinone)(CNT@PDDA)as flexible negative electrode,and crylic rubber cross-linked memberane/tetraethyl tetrafluorate acetonitrile electrolyte(ACM/Et4 NBF4-AN)as the quasi-solid-state electrolyte,organic asymmetric supercapacitor were assembled at the same time.The electrochemical results showed that area specific capacitance of the as-assembled flexible organic asymmetric supercapacitor was 79.6 mF/cm2 at the current density of 2 mA/cm2 and its volumetric energy density was 1.63 mW·h/cm3 at the power density of 63.5 mW/cm3.The capacitance retention of CNT @ PDBS//ACM/Et4 NBF4-AN//CNT @ PDAA organic asymmetric supercapacitor was about 30.5% after only 7 500 cycles,exhibiting bad cycle performance.After 8 000 charging-discharging cycles,specific capacitance retention of pca-CNT @ PDBS//ACM/Et4 NBF4-AN//CNT@PDAA was 80.5%,presenting much better cycle performance. [ABSTRACT FROM AUTHOR]

In order to study taxonomic value and systematic significance of Hydrangea L. as well as clarify phylogenetic relationships among the genus and its related ones, pollen samplings of 41 species of Hydrangea and its related species from China and surrounding areas were observed under scanning electron microscope(SEM). The results were as follows: the pollens of all these species were tricolporate; the pollen morphology were most subprolate and a few subspheroida; ellipse or circular in equatorial view; circular or sometimes triangular in polar view. The ornamentations on the exine can be reticulate ornamentations or perforate ornamentations. The ornamentation in the mesh could be smooth or granular bulged. The above-mentioned species could be divided into four groups according to the pollen morphology and ornamentations on the exine, the characters of each group were respectively pollen morphology subprolate, ornamentation on the exine reticulate; pollen morphology subprolate, ornamentation on the exine perforate; pollen morphology subspheroida, ornamentation on the exine reticulate; pollen morphology subspheroida, ornamentation on the exine perforate. according to the ratio of polar axis to equatorial axis, these species can be further divided into eight types. These indicate that the pollen characters can provide valuable evidence for infrageneric taxonomic treatments and species circumscription. However, this evidence shows limited value in diagnosing some major clades of phylogenetic trees reconstructed in previous studies. Further studies including broader sampling and new evidence of Hydrangea pollen are needed to explore its taxonomic and systematic values. [ABSTRACT FROM AUTHOR]

In order to ensure the safety of filling stope and ore mining efficiently, it is necessary to study the interaction between the filling and surrounding rock in different strength periods, which influences the stability of filling stope.The paraffin was selected as the contact material to simulate the early strength of the filling body, and also considering the complexity of the stress environment in the contact zone, the non-uniform stress in the contact zone between the wall rock and the early-strength backfill was simulated.In order to effectively characterize the regional instability in the contact zone and realize the transformation from qualitative analysis to quantitative evaluation, the PVC plastic foil was placed on the contact face between the surrounding rock and the early strength filling body.Combined with the microscopy imaging, electron microscope scanning, AE monitoring and strain monitoring, the laboratory experiment of the interaction between the surrounding rock and the early strength filling body under different load conditions was studied.The strain change, crack growth deformation evolution, stability failure of cemented backfill and surrounding rock complex were monitored and analyzed.The results show that the deformation of the contact zone increases rapidly, the strain value fluctuates greatly and the abrupt change is obvious.After loading, the paraffin in the contact zone shows three different damage characteristics: one is spiral damage, the second is the parallel type of damage, the third shows the characteristics of cross-damage, and the strain around the contact zone shows a steady increasing trend. The results also show the complex mechanical and deformation characteristics of filling body and surrounding rock, which has a certain guiding significance to ensure the stability of the stope with the early strength filling body.The synchronization between crack propagation and internal damage is realized.The study provides a research idea for further studying the mechanical properties of backfill and surrounding rock complex under two-dimensional and three-dimensional loads. [ABSTRACT FROM AUTHOR]

Objective: To investigate the remineralization of diode Laser and CPP-ACP on the initial enamel caries on primary teeth. Methods: A total of 40 samples of retained mandibular primary central incisors were collected, building artificial enamel caries lesions and randomly divided into five groups: control group(A), DiodeLaser group(B), CPP-ACP group(C), Diode Laser first and E CPP-ACP later group(D), CPP-ACP first and DiodeLaser later group(E). The Mole percentage of each sample was evaluated using energy dispersive X-ray analysis, performed from the five groups. We use scanning electoron microscope to observe the enamel surface structural changes. Results: After remineralization, the Mole percentage of C, D, E group were higher than A group(P<0.05), the D, E group was higher than C group(P<0.05). A and B group have no statistical significance(P>0.05). The mineral deposit was observed by the scanning electron microscope in samples of three groups after remineralization, except samples of the control group. Conclusion: Diode Laser cooperate with CPP-ACP promote the remineralization of initial enamel caries on primary teeth,but the remineralization ability is better to CPP-ACP group. Besides, DiodeLaser group demonstrate no abilit of remineralization in this research. [ABSTRACT FROM AUTHOR]

Objective: The shear strength of three resin adhesives and pure alumina veneers was determined by sandblasting, silica hydrothermal heat treatment and silane coupling agent. After the surface treatment, the shear strength of three kinds of resin adhesives and pure alumina was determined. Methods: Thirty cases of the high purity α-Al2O3 pure alumina specimens were randomly divided into three groups: group A（SACTM resin adhesive）, group B（Vorilink N resin adhesive）, group C（RelyXTM Unicem adhesive）, with 10 cases in each group. After bonding with the specimen, the shear adhesive strength was tested after incubation at 37 ℃ for 24 hours. The failure modes of the bonding interface of each specimen were observed under scanning electron microscope. Results: The bonding strength of SAC resin adhesive was（25.91±2.97）, which was the highest in the hree kinds of resin adhesives（P<0.05） and was higher than that of Vorilink N（18.37±2.11） and RelyXTM Unicem was（9.98±1.22）（P<0.05）. Group A was mixed for all, Group B had internal damage to the adhesive. Group C had both damage and interface damage and internal damage of the adhesive. Scanning electron microscopy showed that there were many resin residues in the adhesive cross section of group A and B, the residual resin on group C was few. Conclusion: Different resin adhesives had an effect on the bonding strength of pure alumina specimens. The SACTM adhesive had the best bonding effect. [ABSTRACT FROM AUTHOR]

Taking rutile titanium dioxide as raw material and the slurry concentration, the stirring velocity and the coating agent ratio of zirconium and cerium as influencing factors, the L9 (34) orthogonal experiment is con ducted to study the optimum technical conditions for zirconium and cerium dualistic coating on the rutile titan-- um dioxide. The optimal condition is determined through Zeta potential analyzing, and the structure and performance of the obtained base material and the coated sample are characterized by sedimentation experiment, scanning electron microscope(SEM), and transmission electron microscope (TEM), etc. The results show that a relatively stable coating layer was formed. The optimum process conditions of the rutile titanium dioxide ZrO2-CeO2 coated was obtained. [ABSTRACT FROM AUTHOR]

Polyimide (PI), graphite and copper powder mixed in different proportion filled polytetrafluoroethylene (PTFE) to form a new composite material, respectively in MMU-2 friction and wear testing machine for tribological performance tests, and will wear after sample in JMS-5600 scanning electron microscope observation of friction surface grinding crack and transfer of composite materials, and determine the best proportion. In order to study the influence of test conditions on the tribological properties of materials, the optimal ratio of PTFE matrix composites was tested again by changing test conditions. The results show that polyimide can enhance the wear resistance of PTFE, and increase the strength of the transfer film binding to the dual parts. When the mass fraction of PI is 25%, graphite mass fraction is 5%, and Cu powder mass fraction is 5%, the tribological performance of the material is the best. When the sliding velocity is more than 4.5 m/s, the load is greater than 300 N, the sample surface temperature were greater than 120 °C, composite material has entered into the phase of high temperature and friction, the friction surface creep, transfer film a burning phenomenon. [ABSTRACT FROM AUTHOR]

Based on the shale samples from Niutitang Formation in Micangshan-Hannan Uplift, some technical experimental devices, such as X-ray diffraction(XRD),low-temperature nitrogen gas adsorption and argon ion figuring-field emission scanning electron microscope(Ar-FESEM) were used to analyze the relationship between mineral composition and micropore structure of Niutitang-Formation shale. The results show that the mineral composition of Niutitang-Formation shale in Micangshan-Hannan Uplift is complex. The mineral composition are mainly quartz and clay minerals, then feldspar, carbonate minerals and pyrite, and the average content of quartz and clay minerals are 41． 35% and 31． 55% respectively. The brittleness index(BI) of Niutitang-Formation shale distributes mainly in the range from 0. 6 to 0. 8 that demonstrate a good compressibility and brittleness. Some nano-sized fractures are along the edge of particles, and few intergranular pores and dissolved pores are formed by quartz and feldspar. There are lots of bedding cracks, pores among clay particles and cracks between schistose minerals formed in clay minerals. Multiple types of micropores are developed in organic matter,such as pores by hydrocarbon expulsion, fractures between organic matter and other minerals and mold pores. The BET and micropore volume have the positive correlation with the content of clay minerals and organic matter,but not with the quartz and feldspar. And the TOC has a positive correlation with BET but not with micropore volume. Also,the results show that the clay minerals are the main influences on the development of macropores, mesoporous and micropores of Niutitang-Formation shale. However, TOC is the main carrier of micropore which means the macropores and mesoporous are not well-developed in organic matter. The pyrite inhibits the growth of micropore after promoting it due to its own unique pore space structure and interaction with organic matter,and the functional mechanism changes when the content of pyrite increases up to 2. 8%. [ABSTRACT FROM AUTHOR]

A research-oriented experiment on the synthesis, characterization and photo-catalytic property of molybdenum disulfide is designed. In the process of the experiment, sodium molybdate and sulfourea are taken as main materials by adding silicotungstic acid, tetrabutylammonium bromide and oxalic acid as additive. Molybdenum disulfide nanosheet is prepared by hydrothermal method. The students conduct the experiment and us e the scanning electron microscope and X-ray diffraction (XRD) to characterize and analyze the samples independently. The effect of the preparation condition of samples on the catalytic performance is studied. The experiment integrates the knowledge on material synthesis technology, material characterization and catalytic performance test. This experimental mode can effectively help to cultivate students' innovative thinking ability and exploratory spirit [ABSTRACT FROM AUTHOR]

Dietary fiber (DF) has drawn the attention of researchers due to its significant health benefits. Over the past decade greater DF materials from fruits and vegetables are being introduced in the market because of the presence of associated bioactive compounds and balanced compositions. The physicochemical and functional properties of DFs always depend on the food sources, extraction methods and structure of DF. Garlic bulb is consumed worldwide because of its widespread medicinal and nutritional value. During harvesting period, garlic bulb yields a considerable amount of straw which is simply thrown or disposed, causing a severe environmental problem. Garlic straw, with similar compounds to garlic bulb, might be used as a novel source of functional DF. Composition analysis reveals garlic straw consists of 7.15% soluble dietary fiber (SDF) and 72.20% insoluble dietary fiber (IDF), which exhibit different physiological effects on human health. The health effects exhibited by IDF are often not as good as that of SDF due to their different physicochemical and functional properties. Therefore, the aim of this study was to improve the functional properties of IDF from garlic straw with ultrasonic processing technology. IDF was put into a 500 mL beaker and dispersed with 300 mL deionized water. The beaker containing the sample was placed in a thermostatic water bath at initial temperatures of 25℃ for 10 min. And then the mixture was sonicated in ultrasound processor with different liquid-sample ratios, ultrasonic powers and ultrasonic time. After the pretreatment, the mixture was stored at -20℃ and freeze-dried for later analysis. The optimum ultrasonic conditions were obtained based on the responses of glucose absorption capacity from single factor experiments and response surface methodology. The functional properties including cholesterol binding capacity, water holding capacity, oil holding capacity and water swelling capacity were determined. Scanning electron microscope (SEM) and Fourier transformed infrared spectroscopy (FTIR) were used to analyze the microstructure of IDF. Results suggest that liquid-sample ratio of 30:1, ultrasonic power of 700 W and ultrasonic time of 40 min were considered as the optimum ultrasonic conditions for preparation of IDF with good glucose absorption capacity. Under these conditions, the glucose absorption capacity and cholesterol binding capacity were increased by 12.8% and 45.0% compared to those without ultrasound treatment (P<0.05). Ultrasonic-treated IDF exhibited better color, functional and physicochemical properties than untreated IDF with significant difference (P<0.05). FTIR of control and ultrasonic-treated IDF was basically the same. Structural analysis from SEM indicated that ultrasonic treatment destroyed the microstructure of IDF from garlic straw. Findings from structural analysis revealed that the porosity and surface area of IDF were effectively improved by ultrasound, which proved to enhance functional and physicochemical properties of modified IDF. The positive effect of ultrasound may be useful for functional modification and utilization of DF from garlic straw. [ABSTRACT FROM AUTHOR]