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Microbial remediation has been widely studied due to its low cost, low environmental impact and high efficiency ・ The research hotspots for microbial remediation are the selection of petroleum-degrading microorganisms and the removal effect of multiple microbial complex bacteria on petroleum components, but there are relatively few practical applications and mechanism studies on microbial technology・ This article sorts out various technical means and practical application research of microbial remediation of oil - contaminated soil, reports the mechanism of microbial remediation of petroleum pollutants, and puts forward the future research and development direction of microbial remediation. [ABSTRACT FROM AUTHOR]

Flame atomic absorption spectrometry (FAAS) is an important experiment in instrumental analysis laboratory teaching for undergraduates. Atomic absorption spectroscopy (AAS) is used to quantitatively determine a specific element in real samples, which has the advantages of high accuracy, precision, and selectivity. Zinc gluconate oral solution is a common over-the-counter zinc supplement in daily life. Through independent experiments of undergraduates, a simple and easy-to-operate FAAS method is established to determine the zinc content in zinc gluconate oral solution. This experiment aims to cultivate students' ability to apply theoretical knowledge learned in class to solve practical problems, and achieve the educational goal of "learning for application, and application to promote learning". [ABSTRACT FROM AUTHOR]

The shape memory alloy (SMA) can deform pseudo-plastically under external load, based on which a reusable impact energy absorption structure was designed. According to the classical SMA constitutive model, the finite element model for thin-wall structures was established, and the dynamic characteristics such as deformation modes and energy absorption of different forms of honeycomb structures under different impacting velocities, were analyzed, and the optimal energy absorption performance of the SMA structures was obtained. In addition, through comparison of the energy absorption performance of the SMA honeycomb with that of the aluminum honeycomb, the energy absorption of the SMA honeycomb with different structure configurations was different from that of the aluminum honeycomb under different-velocity impacts, with the optimal structure changes. The work provides a reference for the selection and design of the SMA honeycomb structures. [ABSTRACT FROM AUTHOR]

The research progress of organic amine chemical absorbents is reviewed. The performance evaluation indexes of absorbents, CO2 capture mechanism of different absorbents, existing problems and development trends are reviewed. With the goal of 1.5 °C temperature rise and the vision of carbon neutralization, the research, development and application of carbon capture, utilization and storage technology have attracted more and more attention. Among many carbon capture technologies, the chemical absorption method with organic amine as the absorbent is the most studied and mature carbon capture technology. A number of demonstration projects have been built in the power, cement, chemical and other industries, which is most likely to achieve large-scale carbon emission reduction in the power and industrial sectors. [ABSTRACT FROM AUTHOR]

Water-repellent soil has a very wide application prospect in the field of agricultural engineering. However, it is still lacking in the hydraulic stability of water-repellent clay. The applications are only targeted at water-repellent dry sand so far. In this study, octadecylamine was taken to modify the highly adsorbent expansive soil with water repellency. A systematic investigation was also conducted to explore the water-repellent and hydraulic stability of loose expansive soil with different water repellency after adsorbing water vapor. Five samples were selected as the compacted expansive soil (hydrophilic expansive soil, hydrophilic expansive soil + hydrophilic sand, hydrophilic expansive soil + water repellent sand, water repellent expansive soil, water repellent expansive soil + water repellent sand). The results show that the greater the humidity was, the greater the mass of water vapor adsorbed by different water repellency expansive soil was. At the same humidity, the water repellency shared little effect on the mass adsorbed by soil. The expansive soil with different water repellency (including slight water repellency) was extremely water repellent after adsorption, where all test points were evenly water repellent. The huge specific surface area of water-repellent expansive soil was obtained for the strong adsorption properties. As such, the water repellency of expansive soil further increased to fully adsorb octadecylamine molecules while adsorbing water vapor during adsorption. After compaction, the water-repellent expansive soil and water-repellent expansive soil + water repellent sand samples exhibited water repellency in a large range of moisture content. There was a range of water-repellent moisture content, all of the soil samples were extremely water-repellent. Compared with the rest, the best hydraulic performance was achieved in the water-repellent expansive soil + water-repellent sand mixed sample share. Specifically, the expansion rate of the expansive soil was reduced from 33.9% to 3.45%, and the shrinkage fissure degree was reduced from 18.75% to 3.6%. Hydrophilic expansive soil realized 90% of the expansion within 90 min, while it took 1 680 min for water-repellent expansive soil and water-repellent sand to complete the same proportion of expansion. Water-repellent modification of expansive soil reduced the expansion amount and rate. There was the basically same air entry value of the hydrophilic sample and the water-repellent sample. But the water content corresponding to the air entry value of the water-repellent sample was smaller than that of the water-repellent sample, and the water-repellent expansive soil matric suction followed the same trend as hydrophilic expansive soil, in terms of moisture content. The pore water pressure remained "negative" at all times in the extremely water-repellent expansive soil, as the moisture content changed. There was no "positive" pore water pressure. There were the lower strength parameters c and φ of water-repellent expansive soil, compared with hydrophilic expansive soil. There was no significant change, indicating better mechanical properties after water-repellent treatment. The special hydraulic properties of waterrepellent expansive soil were attributed to that the water-repellent aggregates remained dry inside the aggregates after immersion. This finding can provide a new idea for the application and promotion of water-repellent clay in agricultural engineering. An experimental basis can be offered to fully expand the application scope of water-repellent soil. [ABSTRACT FROM AUTHOR]

Objective In order to find a new absorbent with good absorption performance, low solvent loss, and low energy consumption for CO2 capture, the preparation and performance of guanidine amino acid ionic liquids to capture CO2 in flue gas was investigated. Methods Three kinds of guanidine amino acid ionic liquids with low viscosity, namely [TMG] [Lys], [TMG] [Ala] and [TMG] [Asp] were prepared using tetramethylguanidine (TMG) as a cation and lysine (Lys), alanine (Ala), and aspartic acid (Asp) as anions. The effects of anionic types on CO2 absorption were investigated. Results The alkaline [TMG] [Lys] had a higher CO2 absorption, with a CO2 absorption capacity of 0.64 mol CO2/mol IL under the condition of atmospheric pressure, 45 ℃, and 80 mL/min. The addition of water had a positive effect on the absorption of CO2. The absorption capacity of 30 wt% [TMG] [Lys] aqueous solution increased to 0.99 mol CO2/mol IL and could still keep 0.81 mol CO2/mol IL after 5 absorption-desorption cycles. The decarbonization mechanism of [TMG] [Lys] was analyzed by Fourier transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance hydrogen spectroscopy (¹H-NMR). CO2 mainly reacts with the amino group on the anion to form carbamate to achieve efficient capture of CO2 in the flue gas. Conclusions It can provide reference for the development of new absorbents in industrial CO2 capture. [ABSTRACT FROM AUTHOR]

This paper investigates the impact of surface pollution on abnormal heating with 110kV composite insulators as the research subject. Firstly, infrared inspections were conducted on three full-sized composite insulators at various pollution classes, and the infrared spectrum characteristics of contaminated composite insulators were analyzed. Subsequently, water absorption experiments were performed on silicone rubber flat samples to analyze the effects of pollution on insulator moisture absorption properties and dielectric performance. Finally, tests were conducted on short samples with protective sheaths of six levels of pollution classes in an artificial climate chamber to analyze the influence of leakage current on temperature rise and to assess the impact of pollution on the surface electric field distribution of insulators using the finite element method. The research results indicated that pollution caused and exacerbated abnormal heating in composite insulators. In a high-humidity environment, when the pollution level of full-sized samples exceeded class B, the heating temperature of insulator exceeded 0.5 ℃. Pollution had a more significant impact on the aging of the composite insulator materials; polluted composite insulators exhibited a 'U'-shaped distribution pattern of the surface electric field, with the heating region primarily concentrated in the high-field strength area of the end sheath. The wet pollution state had a significant impact on the electric field of composite insulators, with the maximum electric field strength increasing from the original 4.8 kV/cm to 6.2 kV/cm. The primary cause of abnormal temperature rise in polluted composite insulators was the polarization loss generated by the sheath and the absorption of moisture by pollution, with surface resistive leakage current having a relatively minor influence. This study can serve as a theoretical reference for online infrared diagnostics and the mitigation of abnormal heating issues in polluted composite insulators. [ABSTRACT FROM AUTHOR]

Objective The aim is to develop a suitable organic amine solution for the removal of CO2. Methods The CO2 absorption/desorption performance of piperazine-based organic amine solutions were investigated using PZ, 1MPZ, HEP and AEP as absorbers. Results The CO2 absorption performance of the PZ solution and AEP solution was superior than that of the 1MPZ solution and HEP solution obviously, but the desorption effeciency of the two solutions was relatively low, which was not beneficial to the circulation of organic amine solutions. Although the desorption effeciency of 1MPZ solution was more than 85.00%, its volatility led to a considerable reduction in the CO2 circular absorption capacity, which limited industrial application. While the desorption effeciency of the HEP solution was about 90.00%, and the variation range of both CO2 absorption capacity and desorption effeciency was lower than 1% after 4 cycles of the absorption/desorption experiments. Conclusions The HEP solution has excellent stability, so it is more suitable for the industrial CO2 capture process, and has a great application prospect.  [ABSTRACT FROM AUTHOR]

Since negative stiffness metamaterials are reusable as energy-absorbing materials, it is necessary to investigate the energy-absorbing performances and reusability of negative stiffness metamaterials. The designed negative stiffness metamaterial was prepared with the 3D printing technology, and the energy absorption performance of the metamaterial in the multi-stable mode and the mono-stable mode was investigated by repeated loading experiments. The effect of the residual stress on the energy absorption performance of the metamaterial was studied with the natural aging method. The results show that, the specific energy absorption of the designed metamaterial first decreases and then stabilizes with the increase of the number of loading times in the case of repeated loading. In both the multi-stable mode and the mono-stable mode, the natural aging method can effectively release the residual stresses in the metamaterial, thus improving its repeated energy absorption performance. [ABSTRACT FROM AUTHOR]

Vitamin B12 plays an important physiological role in preventing nervous system diseases, pernicious anemia, promoting nutrient metabolism and livestock production. Mammals cannot synthesize vitamin B12 by themselves. It is only produced by specific microorganisms in the gut in the presence of cobalt, which is difficult to meet the needs of livestock and poultry. Vitamin B12 needs to be obtained through diet. Therefore, vitamin B12 is often added to livestock and poultry diets in production to meet the nutritional needs of livestock and poultry. In this paper, the absorption and metabolic pathways, biological functions of vitamin B12 and its application in livestock and poultry production were reviewed in order to provide reference for its application in livestock and poultry production. [ABSTRACT FROM AUTHOR]

Tn this study, Fe3O4 magnetic material was prepared by co--precipitation method, and polyimid-based polyporous carbon/nano-magnetic iron particles (PTC, PTC/Fe-l, I〉IC/Fe-2, I〉IC/Fe-3 composite absorbent with different amounts of magnetic particles were prepared by vacuum freeze-drying and high-temperature pyrolysis. The excellent heat resistance of polyimide ensures the integrity of pore structure during high temperature pyrolysis. The complete porous structure can improve the impedance matching condition. The addition of an appropriate amount of nano-magnetic iron particles can improve the dielectric loss and increase the magnetic loss, which makes the electromagnetic wave decay rapidly in the absorber. When I/Fe-2 thickness is 4,57 mm, the minimum reflection loss (RLmm) is -24.1 3 dB. When I/Fe-2 thickness is 4,89 mm, the effective absorption bandwidth (EABW, greater than 9()%EMW absorption, RL less than -10 dB) is 2.54 GHz. Tn addition, when PTC/Fe-3 thickness is 4. 91 mm, RL ]rijH is -54. 43 dB, and when I〉IC/Fe-3 thickness is 5.18 mm, EABW is 2.65 GHz. The polyimid-based multi-pore carbon/nano magnetic iron particle absorbent designed in this work has excellent EMW absorption performance and can be used as a candidate for absorbing agent. [ABSTRACT FROM AUTHOR]

Mineral nutrients are essential substances for potato growth and development, and they are the basis of its life activities. Nitrogen, phosphorus, potassium and some medium and trace elements play an extremely important role in the formation of potato yield and quality. In this review, the demand, absorption and transfer of mineral nutrients in potato growth and development were summarized, and the effects of soil conditions, growth stage and water and fertilizer management on mineral nutrition were analyzed. By expounding the physiological and biochemical functions of mineral nutrition, the effects of minerals on the growth of potato roots, stems and leaves, yield and quality were summarized. Finally, the existing problems and the prospect of future research were put forward, aiming at providing reference for the study of mineral nutrition and effective cultivation management of potato. [ABSTRACT FROM AUTHOR]

-In order to clarify the synergistic effect of 3% lecithin + vitamin E (AnnGro® ) on glyphosate and its absorption and conduction characteristics in plants. Alternanthera philoxeroides was taken asexperimental material. The ED50 and ED90 values of AnnGro® mixed with two glyphosate-isopropylammonium (FD and RD) were calculated by bioassay, and the surface tension, and the contact angle of the liquid with the leaf surface were tested. The absorption and conduction of 14C-glyphosate in A. philoxeroides were measured by isotope tracer technique. The results showed that A. philoxeroides died one day earlier when treated by two herbicides mixed with AnnGro® than by the herbicides alone. ED50 and ED90 values were significantly decreased by 34.9%, 21.4%, and 35.9%, 23.3% respectively. The surface tension and the contact angle between the liquid and the leaf were significantly decreased. Four days after treatments, the total absorption amount of 14C-glyphosate, the total conduction amount in plant and the downward conduction amount of 14C-glyphosate in the treatment of 14C-glyphosate + AnnGro® were 2.33, 2.34 and 2.36 times compared with the treatment of 14C-glyphosate only. In conclusion, AnnGro® improved the control efficacy of glyphosate on A. philoxeroides by increasing the absorption and the conduction in A. philoxeroides. [ABSTRACT FROM AUTHOR]

Based on the CCL corpus and the full-text retrieval system of Chinese books, the author investigates the lexicalization process, motivation and mechanism of " (zhishi)” from a diachronic perspective. The results show that the cross-layer structure" (zhishi)" first appeared in the Wei, Jin and Six Dynasties. In the Tang Dynasty, it was lexicalized into adverbs under the joint action of prosodic constraints, the expansion of subsequent components, the change of syntactic position and the increase of frequency of use. Reanalysis is an important mechanism for the lexicalization of “(zhishi)”. Similarly, in the Tang Dynasty, the adverb “ (zhishi)" was also grammaticalized into a conjunction under the mechanism of context absorption. “ (zhishi)" as a cross-layer structure, an adverb and a conjunction is all used in modern Chinese. [ABSTRACT FROM AUTHOR]

As one of the three essential nutrients for crops growth and development, the importance of phosphorus in potato production is self-evident. Phosphorus deficiency is one of the important limiting factors of potato production in China. Improving the phosphorus efficiency of potato is the best way to deal with the phosphorus stress in potato production. The research results of phosphorus efficiency differences and related physiological responses of different potato genotypes were systematically summarized, and the future research direction for improving potato phosphorus efficiency was prospected so as to provide a reference for the efficient utilization of potato phosphorus. [ABSTRACT FROM AUTHOR]

To investigate the ability of energy absorption of composite beams with corrugated web in the crash process, the drop tests of composite beams with corrugated web are carried out, and the morphology of fracture, load and energy history curves are obtained. Based on the ABAQUS/Explicit platform, a simulation analysis model is developed to simulate the impact collapse process of composite beams with corrugated web by secondary development. The improved Hashin criterion and Choi‑Chang criterion are used with Cohesive interface element. The anisotropy and progressive damage of composite laminates are implemented. Specific energy absorption (SEA) and average loads are obtained by numerical simulation, which is verified by experimental results. Based on this model, further studies on the energy absorption of composite beams with corrugated web are analyzed with different wavenumbers. The progressive damage of corrugated web beams under impact loads are simulated by the developed FE model. The relative errors of average crushing load are small, which verifies the validity of the FE model. When the wave length of web is defined, the length of corrugated web beams has influence on energy absorption under impact. The shorter beam with corrugated web is instability and ineffective in energy absorption. [ABSTRACT FROM AUTHOR]

Objective The advantages and disadvantages of reduction absorption and oxidation absorption tail gas treatment processes in the application process of natural gas purification plants were clarified. Methods The adaptability of the two exhaust gas treatment processes was clarified by comparing the process principle and flow, key operation control and main process parameters, the impact on sulfur recovery and sewage treatment devices, energy consumption and material consumption. Results Through comparative analysis, it can be concluded that the process flow of Cansolv tail gas treatment is more concise, and the desulfurization solvent has obvious absorption performance advantages, which also has adverse effects such as DS desulfurization solvent purification, equipment corrosion protection, and S02-containing sewage treatment. Conclusions Based on the advantages of high efficiency of desulfurization solution, the Cansolv process has lower comprehensive energy consumption, material cost, land occupation and investment than the Scott process, and has better applicability. [ABSTRACT FROM AUTHOR]

Objective The CO2 absorption process under high gravity environment is simulated so as to provide guidance for the optimization of experimental process parameters. Methods An Aspen Plus calculation model for CO2 absorption using NaOH alkaline solution under high gravity was established, and the influence factors on the CO2 removal rate were investigated. Results While the high gravity reactor was equivalent to a conventional packed tower through the equivalent conversion method, the influence of sodium hydroxide mass fraction, solution feed rate and pressure on the CO2 removal rate were similar to that of the high gravity laboratory value, but the simulated value was only about 1/2 of the experimental value. The corrected simulation results were close to the experimental values, and the average deviation was only 0. 77%. Conclusions The established CO2 absorption model under high gravity environment is accurate and reliable, which can provide some directional guidance for subsequent experiments. [ABSTRACT FROM AUTHOR]

Wetland is an important part of the ecosystem, and the investigation of wetland pollutant migration under the combined effect of submerged vegetation and bed absorption boundary can provide a reference for wetland design and maintenance. The random displacement model based on the Lagrangian method is adopted to simulate the transport process of instantaneously released pollutants in wetlands with dense rigid submerged vegetation and bed absorption boundary by setting different vegetation densities and bed absorption probabilities for the pollutants. Results indicate that the increase of the bed absorption probability accelerates the average migration velocity of the pollutant particle cloud and weakens its longitudinal dispersion, while the increase of vegetation density inhibits the bed absorption, extending the stay and greatly dispersing the distribution of the pollutants in the wetland, thereby giving full play to the comprehensive purification function of the wetland. When the absorption probability exceeds 10%, the absorption boundary of the bed can be regarded as a completely absorptive boundary. Conseqently, the use of a substrate with high absorption probability in wetland design is unnecessary. [ABSTRACT FROM AUTHOR]

BACKGROUND: It is of great significance for evaluation, early warning and remediation of antimony contaminated soil to study the sorption factors affecting Sb(Ⅲ) adsorption in soil. OBJECTIVES: To investigate the forms of Fe and Mn oxides and controlling factors of Sb(Ⅲ) adsorption in soil. METHODS: The physicochemical properties, mechanical composition, and main chemical composition of soils from 10 different areas were determined by chemical method, inductively coupled plasma - optical emission spectrometry and atomic fluorescence spectrometry. The contents of different forms of iron and manganese and the saturated adsorption capacity of soils to Sb(Ⅲ) were determined by atomic absorption spectrometry. The correlation analysis, principal component analysis and factor analysis of soil saturated adsorption capacity to Sb (Ⅲ), soil physicochemical properties, mechanical composition, iron and manganese oxides and their forms were carried out by SPSS 21. 0. RESULTS: On the basis of studying the influencing factors of soil adsorption of Sb(Ⅲ), the main controlling factors were further studied. The saturated adsorption capacity of soil to Sb (Ⅲ) was between 0. 63mg / g and 3. 98mg / g, and was related to soil type with the order of red soil>brown soil>yellow soil>cinnamon soil>sandy soil. According to the correlation analysis results, the saturated adsorption capacity of soil to Sb(Ⅲ) was significantly positively correlated with cation exchange capacity, total iron oxide, amorphous iron content, and was positively correlated with free iron content, amorphous manganese content and free manganese content. The principal component analysis and factor analysis showed that these six factors were the main controlling factors affecting the adsorption of Sb(Ⅲ) in soil, and the influence degree was: total iron oxide>cation exchange capacity>amorphous iron content>free iron content>amorphous manganese content>free manganese content. CONCLUSIONS: The adsorption capacity of soil to Sb(Ⅲ) is significantly affected by the total amount of iron and manganese oxides and their forms. [ABSTRACT FROM AUTHOR]

The problem of global warming caused by large amounts of greenhouse gas CO2 emissions has attracted a great deal of attention from countries around the world. The use of liquid absorbents to capture CO2 has been actually used in the process of industrialization. According to Henry’s law, the absorption and regeneration processes must be performed at low and high temperatures, respectively, which requires more energy consumption. As a solution, adding nanoparticles to the absorbent can achieve the goal of reducing the energy required for the absorption and regeneration process. This article reviews the current research status of nanoparticle-enhanced alcohol amine absorbents in improving the reaction kinetics of the absorbent and reducing the energy consumption of the absorbent regeneration. Based on the traditional alcohol amine CO2 absorbent, the nanoparticle-enhanced properties are enhanced from two aspects: mechanism and phenomenon. The research progress and development trend of absorbents are analyzed, and corresponding evaluations, demonstrations and suggestions are provided for the selection and utilization of CO2 absorbents. [ABSTRACT FROM AUTHOR]

thermoplastic elastomer (TPE) based on HIPS/ethylene-vinyl acetate copolymer (EVA) /waste rubber tire (WGRT) powder composite was prepared by melt blending method with styrene-butadiene-styrene block copolymer (SBS) as compatibilizer. The mechanical properties, dynamic mechanical properties and low speed impact properties of HIPS/EVA/WGRT composites with different mixing ratios were systematically studied. The results show that the mechanical and dynamic mechanical properties reach the best when the HIPS/EVA/WGRT weight ratio is 40/5/55,and the impact absorption properties of the materials increase gradually with the increase of the speed in the experimental range. [ABSTRACT FROM AUTHOR]

Nitrogen is one of the essential nutrient elements for plant growth and development. In agricultural production, large-scale application of nitrogen fertilizers is one of the main means of increasing crop yield, but this has led to serious problems such as the poor nitrogen use efficiency（NUE）of crops and environmental pollutions. Therefore, improving crop nitrogen use efficiency is crucial for achieving the sustainable development of agriculture. Nitrate is one of the main nitrogen sources for crop absorption and utilization. In order to adapt to the change in nitrate content in the soil, plants have evolved two nitrate transport systems with different affinities to achieve effective absorption of nitrate. However, most of the nitrate absorbed by plants from the soil needs to be transported to the aboveground, and then go through a series of assimilation reactions, before it can be utilized by plants. Therefore, in-depth studies of the metabolic processes and regulatory network of nitrate become the key to improving crop nitrogen use efficiency. This article summarizes the molecular mechanisms of nitrate uptake, transport and assimilation, as well as the identities of related regulatory factors, and introduces the latest advances in improving nitrogen use efficiency, in order to provide a reference for devising strategies to understand the nitrate regulatory network and improve crop nitrogen use efficiency. [ABSTRACT FROM AUTHOR]

The research progress of traditional ionic liquids, functionalized ionic liquids and phase-change ionic liquid absorbents in CO2 capture was introduced, and the factors affecting the absorption of CO2 by ionic liquids were discussed from different aspects such as absorption capacity, viscosity and temperature. Ionic liquid absorbents should take low cost, low viscosity and high absorption capacity as the future research focus and development direction, which will help to achieve the great goal of "carbon peaking and carbon neutralization", which has important scientific significance and application prospect. [ABSTRACT FROM AUTHOR]

The low density of surface functional groups and the lack of adsorption capacity for negatively charged heavy metal ions are the disadvantages of mussel biomimetic chemical preparation materials. In order to solve the above problems, a dopamine quaternary ammonium salt non-woven fabric adsorbent was prepared by a quaternization method. The adsorption experiment results showed that the maximum adsorption capacity of Cr (Ⅵ) was achieved at pH=3, and the removal efficiency reached 95%. The theoretical maximum adsorption capacity obtained by fitting was 31.92 mg/g. The XPS results showed that the adsorption of Cr (Ⅵ) was related to the quaternary ammonium salt groups and protonated amino groups. In addition, the quaternary ammonium improved the regeneration performance. Dopamine quaternary ammonium salt non-woven show broad application prospects in the field of Cr (VI) adsorption and removal. [ABSTRACT FROM AUTHOR]

Light-aggregate porous concrete can be applied to traffic noise control because of its light weight, porosity and good weather resistance. This experiment developed a new light-aggregate porous concrete using fly-ash cenospheres, namely solid wastes from thermal power plants, as aggregate and cement as cementitious material. It could be applied to the sound absorption material of the road noise barrier. Impacts of two factors, namely molding pressure and aggregate-to-cement ratio, on the acoustic performance were investigated through experimental characterization. Horoshenkov & Swift model was also used to inverse calculate the tortuosity and flow resistance of the material to investigate the effect of molding conditions on them. The results show that with the increase of pressure, the first peak frequency of sound absorption of the specimen shifts to low frequency and the absorption coefficient at the peak decreases. With the rise of aggregate-to-cement ratio, the peak frequency of sound absorption shifts to high frequency, and the absorption coefficient at the peak increases. The calculation results of the inverse computation show that the fitting degree R2>0.8, which is credible. Under the condition of 0.9 aggregate-to-cement ratio, the forming pressure is positively correlated with the tortuosity and flow resistance. While under the forming pressure of 0.2 MPa, the aggregate-to-cement ratio is negatively correlated with the curvature factor. [ABSTRACT FROM AUTHOR]

The uniform asymptoticity of the 2D g-Navier-Stokes equation with nonlinear damping in a bounded domain was studied. The existence of the uniform absorption set of the process family and the satisfaction of the uniform condition (C) were proved, and the uniform attractors of the 2D g-Navier-Stokes equation with nonlinear damping were obtained. [ABSTRACT FROM AUTHOR]

The micro-nano bubbles which were mixed by CO, air and water were applied to the oxidation of CO, and the effects of various factors on the system were studied. The results show that the optimal reaction temperature is 25 ℃ and when the volume fraction of CO is 0.15%,the initial water temperature is 25 ℃,the pH is 7,the oxidation absorption efficiency of CO is 48.33%.Under this condition, the CO removal rate of tail gas can be increased to 88.51% after five cycles. In addition, the removal of CO first increased and then decreased with the increase of SDS, Mn2+, Fe2+ and NH+4 concentration, and the acid condition can promote the oxidation absorption of CO. Mechanistic analysis shows that hydroxyl radicals（·OH） play a key role in the CO oxidation process. [ABSTRACT FROM AUTHOR]

The doping process, passivation and photovoltaic properties of 70 nm ultra-thin poly-silicon were studied in this paper. The optimal doping process for 70 nm ultra-thin poly-silicon was identified, the results show that when the ion implantation dose is 3. 2 × 10 15 cm - 3 and annealed at 855 ℃ for 20 min, the passivation properties of 70 nm ultra-thin poly-silicon is comparable to that of conventional 120 nm poly-silicon, and the surface doping concentration value of 5. 6 × 10 20 atoms/ cm 3 for 70 nm ultra-thin poly-silicon is achieved, which is much higher than that of 120 nm doped poly-silicon (2. 5 × 10 20 atoms/ cm 3 ). Based on the characteristic of reduced thickness and heavy doping for 70 nm ultra-thin poly-silicon, the conversion efficiency of TOPCon solar cells processed on large area (6 inch) Cz wafers significantly improves due to the low parasitic absorption and excellent filed passivation effect. The Isc is increased by 20 mA and 0. 3% improvement of FF, leading to an absolute efficiency gain of 0. 13% for the champion conversion efficiency, as well as low series resistance. [ABSTRACT FROM AUTHOR]

ZnO/HNTs nano composites are prepared by in-situ growth of ZnO nanoparticles on the surface of halloysite nanotubes (HNTs) using zinc nitrate as zinc source. The ZnO/HNTs are characterized by X-ray diffraction, scanning electron microscope, X-ray energy spectrometer, specific surface area and porosity analyzer, UV visible near infrared diffuse reflectance, and ZetaSizer Nano 9() dynamic light scattering (T)LS) particle size analyzer tester. The adsorption and photocatalytic degradation performance of HNTs, nano-ZnO and ZnO/HNTs composite materials for methylene blue (MB) under UV illumination are investigated. The results show that the nano-Zn() is evenly distributed on the surface of HNTs. Compared with nano-Zn(), the specific surface area of ZnO/HNTs is as high as 44.305 m2/g, which is 1.2 times higher. For ZnO/HNTs, the degradation rate of 1 5 mg/L methylene blue with degradation time of 1.5 h is close to 1()()%, which is much higher than that of nano-ZnO (80.2%), and its repetitive catalytic efficiency maintains remains 80.4% after 10 cycl es. Tt is shown that the introduction of HNTs greatly improved the catalytic activity of ZnO/HNTs. [ABSTRACT FROM AUTHOR]

This article reviews the equipment that can effectively absorb CO2 in the exhaust gas and introduces the application status of the traditional reactor, tower equipment, membrane reactor and the high gravity reactor. This article points out the application conditions of different absorption equipment by summarizing their device types and use effects and compares the maximum absorption rate of CO2. Based on the above analysis, the types and absorption performance of the CO2 absorption equipment are presented for the reference of application. [ABSTRACT FROM AUTHOR]

ZnO/HNTs nano composites are prepared by in-situ growth of ZnO nanoparticles on the surface of halloysite nanotubes (HNTs) using zinc nitrate as zinc source. The ZnO/HNTs are characterized by X-ray diffraction, scanning electron microscope, X-ray energy spectrometer, specific surface area and porosity analyzer, UV visible near infrared diffuse reflectance, and ZetaSizer Nano 9() dynamic light scattering (T)LS) particle size analyzer tester. The adsorption and photocatalytic degradation performance of HNTs, nano-ZnO and ZnO/HNTs composite materials for methylene blue (MB) under UV illumination are investigated. The results show that the nano-Zn() is evenly distributed on the surface of HNTs. Compared with nano-Zn(), the specific surface area of ZnO/HNTs is as high as 44.305 m2/g, which is 1.2 times higher. For ZnO/HNTs, the degradation rate of 1 5 mg/L methylene blue with degradation time of 1.5 h is close to 1()()%, which is much higher than that of nano-ZnO (80.2%), and its repetitive catalytic efficiency maintains remains 80.4% after 10 cycl es. Tt is shown that the introduction of HNTs greatly improved the catalytic activity of ZnO/HNTs. [ABSTRACT FROM AUTHOR]

[Objective] The present paper aimed to explore the effects of Cd stress on the absorption and transport of mineral elements in rice.[Method] 29 rice varieties were selected and treated with two groups (0,0.5 mg/kg). The contents of eight mineral elements (Ca, Fe, Zn, Mg, Cu, Mn, K,Na) in the upper and lower parts of rice were measured by atomic absorption flame spectrophotometer.[Result] In the underground part, compared with control group, the effect of Cd on Fe was shown to inhibit absorption; Zn, Mg, K and Na were resistant to Cd, and Zn was more resistant than Cu, and Cd was more competitive than Mn and Mg.Its Cd resistance and competitiveness were greater than that of Ca. Zhuzhen B and Japonica 7623 showed Cd tolerance among the eight mineral elements. [Conclusion] Zhuzhen B was the only rice variety that promoted the absorption of eight mineral elements after Cd stress; Liusha 1 was the least Cd-tolerant rice variety. [ABSTRACT FROM AUTHOR]

In order to clarify the relationship between auxin and Mn toxicity and resistance of rice, and to reveal the regulatory mechanism of Mn toxicity in rice, the effects of Mn stress on the content of free auxin in root tips of rice and the effects of exogenous auxin NAA on the absorption, accumulation and toxicity of Mn in rice seedlings were studied by hydroponic experiments. The results were as follows: (1) The content of free indoleacetic acid in root tips of rice cultivated in 2000 pamol L-1MnCl2, solution decreased significantly, which was only 47.7% of the control treatment: The relative root elongation was also significantly reduced to 71.1% of the control treatment. (2) The content of Mn in root tips increased significantly after adding the polar auxin transport inhibitor NPA to the Mn solution, which was 1.5 times that of the control treatment. (3) After adding NAA into the Mn solution, the Mn content in root tip cell wall was not significantly different from that of the control treatment, but the relative root elongation was significantly reduced while the absorption amount of Mn in plants, the Mn content in root tips and the distribution ratio of Mn into cell of root tips were all significantly increased; The Mn content in the leaves of vitro rice plants immersed in the Mn solution at the stem base was also significantly increased after the addition of NAA: The expressions of OsYSL2, OsYSL6 and OSMTP8.1 in root tips of rice were significantly increased after the addition of NAA under Mn stress. These results indicate that excessive Mn can significantly inhibit root elongation and reduce the level of free auxin in rice root tips. Auxin was involved in the regulation of Mn absorption, transport and toxicity in rice. [ABSTRACT FROM AUTHOR]

This study determined Fe, Mn, Cu and Zn contents in leaves and roots of 1-year-old Aleurites montana potted and hydroponic seedings under different concentrations of aluminum stress, to analyze the absorption and transportation of microelement contents between roots and leaves and to reveal the response mechanism of microelement contents to different concentrations of Al stress. The results showed that aluminum significantly promoted the absorption of Fe, Mn, Cu and Zn in roots for soil cultured seedlings, while exerted insignificant effect on or even inhibited the absorption of microelements in roots of hydroponic seedlings, indicating that the same plant developed different aluminum resistance under different cultured media. The distribution of microelements varied in different organs of A. montana. Most microelements, excluding Mn, were absorbed by roots of potted seedlings while those excluding Fe were concentrated in leaves of hydroponic seedings. Aluminum stress also affected the transport of microelements between different organs in seedlings. The transport of Zn from roots to leaves was promoted when Al concentration was lower than 0.290 mmol-L-1., while the transport was inhibited when it was higher than 0.290 mmol-L-1. The study indicated that there was a significant difference in the effect of aluminum stress on microelements of the A. montana potted and hydroponic seedlings. The potted seedlings had stronger resistance in primary environment compared with hydroponic seedlings. Therefore, in the future stress experiments, the role of primary environment should also be taken into account in addition to the stress resistance of plants [ABSTRACT FROM AUTHOR]

In order to understand the mechanisms of cadmium absorption and accumulation in different tea varieties, pot experiments were conducted to investigate dry weight in aboveground part of different tea plant varieties, Cd content, accumulation and translocation of Cd from soil to different parts of tea plant, and gene expression of Cd-related transport proteins in roots with and without Cd treatment. Results showed that dry weight of aboveground part of different tea plant varieties increased with Cd content. The Cd content in different tea varieties was in order of roots>branches>mature leaves>young leaves. The bioaccumulation factor of Cd in roots of plants treated with Cd ranged from 7.17 to 30.12. The biological transfer factor of Cd from roots to branches, mature leaves, and young leaves in Cd-treated plants ranged from 0.017~0.078, 0.002~0.007, and 0.000 3~0.006 1, respectively. Results showed that the expression of CsZIP1, CsZIP2, CsHMA2, and CsCAX2 was increased in Zijuan, whereas the difference in the expression of CsHMA1 among the four tea varieties （Zhongcha108, Wuniuzao, Zijuan, and Zhenong117）was not significant. In conclusion, when Cd content in soil is more than 0.3 mg∙kg-1 and less than 1.5 mg∙kg-1, we may consider young leaves as safe. [ABSTRACT FROM AUTHOR]

2-Bromo-4-fluoroacetanilide (BFAA) is an intermediate in the synthesis of many Nphenylamides and an important impurity in the synthesis of pesticides. An ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method was developed for the rapid and specific determination of BFAA in rat plasma, tissue, urine and feces to obtain the toxicokinetic information of absorption, distribution and excretion of the compound. Plasma and different tissue samples of rats were obtained and processed by protein precipitation method after intragastric and intravenous administration with different doses of BFAA, and the validated UPLC-MS/MS method was used for detection. The absorption toxicokinetic parameters such as the peak time (tmax), the peak plasma drug concentration (Cmax) and the area under the drug concentration-time curve (AUC(0-t)), and bioavailability of BFAA were calculated. And the tissue distribution and excretion characteristics of urine and feces were investigated. The results of plasma toxicokinetic studies indicated that the drug was rapidly absorbed after intragastric administration, and the tmax value of the plasma concentration of BFAA was (0.2 ± 0.1), (0.4 ± 0.2) and (0.5 ± 0.3) h after given at 200, 500 and 1 000 mg/kg, respectively. The Cmax and AUC(0-t) value were (32.4±5.0), (45.2±1.8), (38.5±3.2) mg/L and (121.2±40.9), (393.3±51.1), (321.9±38.0) (mg/L)·h, respectively. The bioavailability (F) of BFAA reached 34.1%-83.3%, and the plasma drug time curve had a double-peak phenomenon. It is speculated that there may be reabsorption or intestinal-hepatic circulation in animals. The results of tissue distribution studies showed that BFAA was widely distributed in the tissues and mainly distributed in small intestine, stomach and adipose tissue. In addition, a small fraction of BFAA was found in the brain and testis which indicated that the compound could cross the blood-brain barrier and testicular barrier. BFAA was eliminated in most tissues within 24 hours which indicated that there was no accumulation of the compound. The target distribution coefficient study suggested that BFAA has no obvious selectivity for tissues. Excretion through urine and feces mainly occurred within 0 to 48 hours, accounting for 93% and 92% of total excretion, respectively. The total excretion amount in urine and feces is (80.6 ± 29.8) μg, which only accounts for (0.03 ± 0.01) %, suggesting that the excretion in urine and feces is not the main elimination way of BFAA prototype compound in vivo. [ABSTRACT FROM AUTHOR]

[Objeetive] Understand to effect of the photosynthetic characteristies, 15N absorption and distribution of strawberry under different dormancy states. [Methods] The difference of strawberry leaf morphological indexes and photosynthetic characteristics were compared between deep dormany (dwarfed plant) strawberry With non-deep dormaney (not dwarfed plant) during the domancy period of strawberry in winter. The isotopie trarer method was used to study the difference of 15N absorption and distribution of strawberry under different dormancy degrees. [Results] The petiole became shorter and the area of single leaf became smaller as the dormancy strengthened. The net photosynthetic rate of strawberry with deep dormaney was lower than that of strawberry with shallow command the intercellular CO2. concentration of the deep dlomant strawbery was higher. The stomatal chance of the derp dormant strawberry was higher than that of the shallow dormant strawberry from 8:30 am to 10:30 am. In the dormant state, the root system was the organ with the larget dry matter accmulation and the organ with the highest nitregen distribution and utilization nate in strawberry. The root system had the strongest ability to absorb and regulate 15N for the strawberry as the dormaney shallow. The 15N strengthened, while the leaves had the strogest ability to aborb and regulate 15N for he strawberry as ihe domany shallow. The 15N distribution rate of strawberry leaves decreased significantly with the deeping of dormancy. The 15N distribution rate was 18.84% in the deep dormant strawberry leaves, and it was 36.74% in the shallow dormaney leaves. [Coulusion] In winter, the dormaney, the dormaney depth of strawberry affected the photosynthesis, nitrogen uptake and distribution of straberry in solar greenhouse. [ABSTRACT FROM AUTHOR]

[Objective] The present paper aimed to explore the absorption and enrichment of heavy metals cadmium( Cd) and lead( Pb) from jute in different growth stages in heavily polluted soil, and to provide reference for bioremediation of heavy metal pollution of soil and selection of vegetable jute plantation. [ Method] Four jute varieties were planted on soil heavily polluted by Cd and Pb. The contents of Cd, Pb in different growth stages ( seedling stage, flowering stage, mature stage) and different parts ( root, hemp skin, sticks, leaf ( seed) were determined by microwave-assisted digestion and inductively coupled plasma atomic emission spectrometry, the bio virus were determined at the same time. The bio concentration factor, transfer factor and accumulation in jute were analysed. [ Result The total biomass of Funong 4 at flowering stage and mature stage was 21. 53 and 26. 18 t/hm²,respectively, higher than that of the other 3 varieties. The contents of Cd and Pb in each part of the four varieties in all stage were ranked as root > leaves( seeds) > bast > sticks. With the change of growth stage the Cd content in root, bast, stickts of Guimacai2, Funong1,Funong4 and in bast, stickts of Guimacail were ranked as seedling stage> mature stage >flowering stage. The Ph content of each part in each growth stage were ranked as mature stage > flowering stage > seedling stage. The enrichment factor and transfer factor of Cd, Pb in the four varieties were less than 1. 000 at all the growth stage. The accumulation of Cd and Pb in four varieties showed ranked as mature stage> flowering stage> a seeding stage. The highest accumulations of Cd(50.160 g/hm² ) was Guimacail at the mature stage, while the highest accumulations of Pb ( 64. 025 g/hm2 ) was Funong1 at the mature stage. [ Conclusion] When four jute varieties were planted as vegetables, the heavy metal background value of the planting soil should be investigate thoroughly to ensure their food safety. The Guimacail could be popularized and applied as a soil Cd pollution remediation plant. [ABSTRACT FROM AUTHOR]

The paper straw base paper was prepared from bleached softwood pulp and hardwood pulp, and the optimum preparation technology was determined by studying the influence of size ratio, wet strength agent and sizing agent dosage on the general performance index of the base paper. The safety of paper straw base paper was measured by measuring the content of warm water extract. The results showed that the best ratio of raw materials for lining paper and face paper is 30 : 70 and 40 : 60(softwood : hardwood)，the dosage range of wet strength agent for lining paper and face paper is 0. 50% 〜0. 75% and 0. 75 % 〜1. 00% respectively，and the dosage range of sizing agent is 0. 25% 〜0. 30%. Under this condition， the base paper has betterwet strength，tensile strength，absorption，etc. When the dosage of APMP is 30% ,the stiffness of lining paper and face paper increased by 3. 51% and 2.23%, respectively. The water extraction content of lining paper and face paper is only 0. 218% and 0. 206 % respectively, which satisfied the safety of pipette base paper. [ABSTRACT FROM AUTHOR]

In order to study the heavy metal pollutant adsorption of sediment under the phase-separation model, based on the Langmuir isothermal equation, the sediment and heavy metal phases were regarded as two phases and the adsorption process was numerically simulated through two calculation methods: time-step method and UDS method. Firstly, the sediment adsorption process under seven turbulence models was simulated by combining component transport model with UDF using commercial software fluent. The results were compared with the Langmuir model, the feasibility of the method was verified and the model with the highest consistency was selected. Secondly, the adsorption capacity of sediment particles under different sediment concentration and particle size were obtained by using the selected model. And the change trend of cadmium ion concentration in aqueous phase was simulated. The results show that the sediment concentration directly affects the adsorption of water, the smaller the concentration, the weaker the adsorption, the slower the adsorption rate is, the less the concentration is and the less the adsorption can be. The adsorption effect of sediment particle size in water is obvious, but it cannot determine the amount of sediment adsorption. Both UDS and time-step methods have advantages and disadvantages in calculating the adsorption amount under the influence of particle size. The results of the dynamic time obtained by the stepwise method are more appropriate and the numerical results of the adsorption amount obtained by the time-step method are in better agreement with each other. [ABSTRACT FROM AUTHOR]

Due to poor permeability of epithelial cells in gastrointestinal tract, oral bioavailability of poorly soluble traditional Chinese medicines is often low. In combination with the advantages of nano delivery carriers and lipid carriers, lipid nanocarriers (LN) could reduce particle size, enhance particle adhesion, increase drug solubility, improve penetration and absorption, promote intestinal lymph transport, and to a large extent, solve the problem of poor gastrointestinal absorption of poorly soluble traditional Chinese medicine ingredients orally and improve bioavailability. Based on the absorption characteristics of gastrointestinal tract, the application of LN in oral absorption of poorly soluble traditional Chinese medicine ingredients was reviewed comprehensively by literature both at home and abroad, and the LN advantages of improving drug bioavailability were also summarized. [ABSTRACT FROM AUTHOR]

[Objectives] Nitrogen absorption efficiency could be reflected by chlorate tolerance.The objective of this study was to evaluate the effects of chlorate treatment on the phenotype, enzyme activity and absorption of the nutrient element at maize seedling stage, and to screen the inbred lines with different chlorate tolerance. [Methods] In this study, six maize inbred lines including Mo17, Dan340, Wu312, Y53, Ye478 and B73, were planted under 4 mmol·L-1 KNO3 (CK), 2 mmol·L-1 KClO3 (T1) and 4 mmol·L-1 KClO3 (T2)conditions, respectively.A total of eight phenotypic traits, four leaf enzyme activity, concentration of protein, and mineral nutrients were evaluated. [Results] The results showed that chlorate could significantly inhibit the phenotypic traits of maize inbred lines, especially for plant height, leaf length, SPAD value and shoot dry weight, with an average decrease of more than 38.96%, 37.93%, 55.85% and 31.58%, respectively.The effects of chlorate on the enzyme activity of maize inbred lines showed a significant increase in content of protein (Cpr), while glutamate synthase(GOGAT)decreased significantly.The absorption of N and Zn was inhibited by chlorate treatment in maize. [Conclusions] The responses of plant height, leaf length, SPAD value and shoot dry weight to the chlorate could be used as a valid index to identify inbred lines with chlorate tolerance.According to the responses of shoot dry weight to the chlorate, we found that B73, Y53 and Wu312 were chlorate sensitive varieties; and Mo17, Ye478 and Dan340 were chlorate tolerant varieties.These foundings provide a new idea to screen maize inbred lines with high efficiency absorption of nitrogen. [ABSTRACT FROM AUTHOR]

This study examined variations in the enrichment and transfer of heavy metals by different industrial hemp varieties. Five main varieties（ym1~ym5）of industrial hemp were used as experimental materials to repair farmland seriously polluted by heavy metals in min⁃ ing areas of Yunnan Province. Among the five industrial hemp varieties, ym1 absorbed the most Pb and Cd, ym3 absorbed the most As, Cu, and Zn, while ym5 had the lowest absorption of Pb, Cu, Cd, and Zn in mature roots. The maximum absorption of As, Cu, and Cd by stems and leaves was observed in ym3, and the maximum absorption of Pb and Zn occurred in ym1 and ym2, respectively. The maximum absorp⁃ tion of Pb and Cd by seeds was seen in ym2, of As and Cu was seen in ym5, and of Zn was seen in ym3. Seeds of ym1 showed the least ab⁃ sorption of Pb, As, and Cu, and the least absorption of Cd and Zn were seen in the seeds of ym4 and ym2, respectively. The enrichment coef⁃ ficients of stems and leaves in the five varieties were greater than that of roots, except Cu. The transport coefficients of roots to stems and leaves were all greater than 1. In summary, ym1 can be used for Pb repair, and ym3 is suitable for As, Zn, Cu, and Cd repair. [ABSTRACT FROM AUTHOR]

【Objective】Leaf chlorosis happened in grafted eggplant in Emeishan city in recent years, which caused considerable yield reduction. The experiment was carried out in order to investigate the reasons and corrective measure. 【Method】Effects of combining base fertilizer with spraying magnesium fertilizer on leaf on scion-root and grafted eggplant were studied. Changes in magnesium content were monitored to study the effects of such changes on leaf yellowing. 【Result】Magnesium content of different position leaves of scion-root and grafted eggplant were tested at three different fruit development stages in different fertilizer conditions. The results showed that magnesium content and change trend in leaves were completely different between scion-root eggplant and grafted eggplant. Under the same treatment conditions, magnesium content of scion-root eggplant was always significantly higher than grafted eggplant in different position leaves at different stages. The magnesium content in grafted eggplant leaves presented a tendency to drop sharply from the second fruits development stage, which was different from that in scion-root eggplant. Magnesium content of some position leaves increased in scion-root eggplant and grafted eggplant with four treatments. But all treatments couldn’t improve the leaf chlorosis. 【Conclusion】Leaf chlorosis may be caused by magnesium deficiency in grafted eggplant according to the results. We presume that the grafting affect the absorption and translocation of magnesium in eggplant and eventually give rise to the leaf chlorosis. [ABSTRACT FROM AUTHOR]

A zinc ion fluorescent probe molecule with pyrazine group is studied by density functional theory. The ground state equilibrium geometry, absorption properties, orbital energy, excited state geometry and emission properties were studied theoretically. The results show that when the probe molecule is bound to zinc ion, the zinc ion complex exhibits better symmetric structure. The absorption wavelength and emission wavelength are blue shifted, simultaneously, the oscillator strength increases. In addition, the change of electron cloud reflects the charge transfer in the molecule. The synthesized results show that the probe molecule can detect zinc ions. [ABSTRACT FROM AUTHOR]

With the rapid development of social and industrial processes, heavy metal ions in water have serious harm to the environment and human health. People pay more and more attention to the treatment of wastewater containing heavy metal ions. In this paper, a variety of Fe3O4 nanoparticles were prepared by co-precipitation method and changing reaction conditions (the starch-iron ion ratio, the iron ion-sodium hydroxide ratio, reaction time and reaction temperature) with starch as template. The influence of various absorption conditions, like the adsorption time, pH value, temperature, and concentration of Cu2+ on the adsorption performance of Cu2+ were investigated. The results show that the adsorption effect on the Cu2+ of wastewater was the best when the adsorption time was 1 h, the pH value was 11, the temperature was 50 °C and the concentration of Cu2+ was 0.338 mmol/mL. And the absorption efficiency was reaching 90%. [ABSTRACT FROM AUTHOR]

[Objective]To provide technical support for the selenium-rich production of edible cassava, natural selenium-rich varieties and high efficient exogenous selenium strengthening technology were screened out through field experiments. [Method]The natural selenium enrichment capacity of 7 cassava varieties was measured under two soil environments with background selenium values of 1. 45 mg/kg and 0. 63 mg/kg respectively. Then, different amounts of exogenous selenium were applied by spraying, root fertilization, leaf spraying+root fertilization during the tuber swelling period of cassava to study the differences in the content of root selenium and the utilization rate of exogenous selenium in cassava under different strengthening methods and amounts. [Result] Under natural conditions, the selenium content in the root tuber of 7 edible cassava varieties fluctuated between 0. 017 and 0. 109 mg/kg. The selenium content and absorption efficiency of the root tuber of NK-10 and NZ199 were higher than those of the other 5 varieties, while the transfer efficiency of the two varieties to the ground was lower than that of the other 5 varieties. The root selenium content of cassava root under the condition of exogenous selenium strengthening was all higher than that of the control, and the selenium content of the roots increased at first and then decreased as the amount of exogenous strengthening increased. The utilization rates of exogenous selenium by foliar spraying, root fertilization and leaf spraying+root fertilization were 0. 55 %-1. 62 %, 0. 16 %-0. 61 % and 0. 06 %-0. 32 %. [Conclusion]The natural selenium enrichment capacity of different cassava varieties varied greatly, among whic h NK-10 and NZ199 had strong natural selenium enrichment eapacity. Under the condition of exogenous selenium, proper amount of exogenous selenium could effectively improve the selenium content of cassava root, and the utilization rate of exogenous selenium was the highest under foliar spraying. [ABSTRACT FROM AUTHOR]

In the process of measuring the content of metal elements in cigarette soot by atomic absorption method, if the pre-treatment method was used directly, the clarity of the digesting solution was poor and the RSD of the measurement results were high. In order to solve this problem, a pre-treatment method of combined ashing and microwave digestion was proposed. The digestion acid system of microwave digestion and ashing conditions of the muffle furnace were optimized. The results showed that the acid system mainly affected the accuracy of the measurement results. When the volume ratio of HN03, HF and H2O2 was 7 : 0. 5 : 1.5, the microwave digestion effect was the best. The ashing mainly influenced the RSD of the results. When the sample quality was 0. 10 g, the ashing temperature and time were taken at 600 °C and 60 min, respectively, RSD values matched well with predicted values. Compared with direct microwave digestion, the RSD of potassium, calcium, magnesium, iron, manganese, zinc, and copper elements dropped dramatically, using the dry-wet combination method. The results of recovery experiments showed that the RSD of each element was 1. 33% ~ 2. 41% and the average recovery was 97. 77% ~ 102. 05% . Above all, this method had favorable repeatability and accuracy, and could be used for reference in the selection of pretreatment methods for homogenized samples. [ABSTRACT FROM AUTHOR]

[Objectives] Two cadmium-tolerant microorganisms were isolated, and their adsorption and immobilization characteristics of cadmium were explored preliminarily. [Methods] In this study, cadmium-tolerant microorganisms were isolated with a series of cadmium-containing solid media, and I6S rKNA gene sequencing was performed to identify the bacteria. Two strains were cultured in LB liquid culture with 50 mg·L-1 cadmium, and D600 value, pH value, and extracellular polymerization were monitored during the incubation. The different mechanisms of cadmium adsorption and immobilization were studied. [Results] Two strains with strong cadmium tolerance were isolated, and grew well under 600 mg·l-1 cadmium in LB plate. They were identified as Achromobacter sp. (ZXH21)and Pseudomonm sp.(ZXH23)by 16S rHNA gene sequencing. Both strains had certain cadmium adsorption and immobilization ability under 50 mg·L-1 cadmium treatment, and the cadmium removal efficiency was similar. The maximum removal of cadmium by ZXH21 and XXH23 were 36.5% and 33.7% respectively. The removal mechanism of cadmium by both strains was main ly extracellular adsorption, with absorption as a supplement, however, the rate varied. At 72 h. the adsorption and absorption rates of ZXH21 were 25.3% and 0.6% respectively, and those of ZXH23 were 30.6% and 0.1%. Thf : absorptivity of the two strains were quite different, and ZXH2I was 6 times higher than that of ZXH23. [ Conclusions] ZXH21 had stronger cadmium tolerance and more stable removal potential than ZXH23. The main mechanism of cadmium removal by ZXH21 was by the biomass increment and the secretion of solu. ble polysaccharides. Surface adsorption, secretion of insoluble proteins and insolubl c polysaccharides might be the main factors for the cadmium removal of ZXH23. [ABSTRACT FROM AUTHOR]