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In view ol the problems ol incomplete penetration and poor perlormance in the traditional method ol welding thick plate Inconel625 alloy, plasma welding technology was used to weld 8 mm thick Inconel625 alloy, and ERNiCrMo-3 welding wire was used as the lilling material to ensure molding. The microstructure and properties ol the welded joints were analyzed via Optical Microscope (OM), Scanning Electron Microscope (SEM), universal testing machine and microhardness testing machine. The results show that the welded joint has the optimal lorming and mechanical properties under the welding current ol 230 A, welding speed ol 240 mm/min, wire feeding speed ol 1 400 mm/min and plasma gas flow ol 4 L/min. The welded joints show a c Y;-shaped morphology with a wide top and a narrow bottom. The base metal area is austenite equiaxed crystal, the weld zone is mainly composed ol line cellular crystals, and the fusion line area is coarse cellular crystals grown perpendicular to the fusion line, MC carbide and Laves phase will precipitate during the welding process. The tensile strength of the joint is the highest, which can reach 811. 36 MPa, and the Iracture ol the welded joint is ductile Iracture, The hardness ol the weld zone is the highest under all parameters. As the welding heat input increases, the overall hardness of the welded joint increases. When the current reaches 240 A and 250 A, the hardness dillerence of the welded joint is small・ [ABSTRACT FROM AUTHOR]

To realize the resource utilization of zero-discharge production wastewater from the ready-mixed concrete mixing plant, this experiment combined the microstructure detection techniques of the mercury-pressure method, scanning electron microscope, and X-ray diffraction to investigate the role and influence law of wastewater admixture and its storage time on the mechanical properties and microstructure of concrete. The results showed that the 7-day compressive strength of mortar with 100% wastewater admixture increased by 35% and the 28-day compressive strength increased by 16% compared with that of ordinary mortar, while the compressive strength of specimens with other wastewater admixtures increased to a certain extent; the alkaline environment provided by wastewater was beneficial to promote the hydration reaction of cement. The micro-particles contained in the wastewater of ready-mixed concrete production play a filling and bonding role in the microstructure of concrete and improve the compactness of concrete. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Henan University of Science & Technology, Natural Science is the property of Editorial Office of Journal of Henan University of Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Taking Chinese fir wood from plantation as the research object, three technological parameters including hot-pressing temperature (160, 180, 200 °C), hot-pressing time (20, 30, 40 min) and compression ratio (30%, 40%, 50%) were selected, and the compression densification modification test of Chinese fir was carried out by using the full factor experimental design. Based on the mechanical properties, microscopic morphology and crystallinity of wood, the effects of different processing parameters on wood properties were analyzed, and the densification process parameters of Chinese fir wood were optimized. The results showed that the properties of the densified wood prepared by Chinese fir were better under the technological conditions of hot pressing temperature of 180 °C, compression ratio of 50%, and pressing time of 40 min. The flexural strength, flexural modulus of elasticity, tensile strength, and hardness of the densified Chinese fir were 130.4 MPa, 12 338 MPa, 113.1 MPa and 1 631 N respectively, which increased by 112%, 113%, 44%, and 55% compared to the untreated wood. The scanning electron microscope observation showed that almost all the early wood cells were crushed, and there were regular folds along the direction of the wood ray, while some of the late wood cells were crushed, and most of them kept the original cavity structure. The hardness and elastic modulus of the cell wall of the densified wood were 16.7% and 45.7% higher than that of the untreated wood. The crystallinity of wood after compression treatment increased. The crystallinity of cellulose in the untreated wood and compressed Chinese fir was 46% and 53%, respectively. [ABSTRACT FROM AUTHOR]

To understand the effect of acid solution treatment on poly 1, 4-cyclohexylen dimethylene terephthalate(PCT) fiber, the surface morphology, mechanical properties, aging reaction activation energy and infrared spectrum of PCT fibers before and after sulfuric acid and nitric acid treatment were tested and analyzed by scanning electron microscope(SEM), single fiber strength machine, synchronous thermal analyzer(STA) and Fourier transform infrared spectrometer(FTIR). The results show that the acid immersion treatment can cause the shrinkage of PCT fiber, leading to the surface corrosion of the fibers and the occurrence of dents and cracks; The entering of water molecules into the fiber macromolecule gap of PCT fiber causes a simultaneous decrease in breaking strength and elongation at break; The breaking strength of PCT fiber decreased with the increase of acid solution concentration, treatment time and treatment temperature; Unless at a lower concentration and temperature, the sulfuric acid resistance of PCT fiber is better than that of nitric acid; The sulfuric acid resistance of PCT fiber is weaker than that of the polyphenylene sulfide(PPS) and the polytetrafluoroethylene(PTFE) fiber, and better than that of the polyimide(PI) and the Aramid 1313 fiber; Acid solution treatment can lead to a decrease in the activation energy of the aging reaction and molecular stability of PCT fiber. [ABSTRACT FROM AUTHOR]

Maleic anhydride grafted ethylene propylene diene monomer (EPDM-g-MAH) was prepared by melt blending, and the grafting rate was 1.57%. The polylactic acid/ethylene propylene diene monomer (PLA/EPDM) composites with different EPDM-g-MAH contents were prepared by using EPDM-g-MAH as compatibilizer. The grafting amount of maleic anhydride (MAH) was characterized by Fourier transform infrared spectroscopy (FTIR). Mechanical properties, microstructure and non-isothermal crystallization of PLA/EPDM/EPDM-g-MAH were characterized by universal tensile testing machine, simply supported beam impact testing machine, scanning electron microscope (SEM) and differential scanning calorimetry (DSC). The results show that the addition of EPDM-g-MAH improves the compatibility between PLA and EPDM. When the content of EPDM-g-MAH is 1.0%, elongation at break and impact strength of PLA/EPDM/ EPDM-g-MAH are 136% and 103% higher than those of PLA/EPDM, respectively. The crystallinity of system is the highest. EPDM-g-MAH can improve mechanical properties and crystallization properties of composites. [ABSTRACT FROM AUTHOR]

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Ordnance Equipment Engineering is the property of Chongqing University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The ultrafine composite mineral admixture (HP-UA) of fly ash-mineral powder was prepared by grinding treatment. The effects of 15%, 25% and 35% dosage on concrete mechanical properties, durability were studied. It used scanning electron microscope and X-ray diffractometer to analyze the mechanism of its effect on concrete properties. The results show that the addition of HP-UA is beneficial to the improvement of concrete mechanical properties, shrinkage resistance, water penetration resistance, chloride ion penetration resistance, sulfate corrosion resistance. It had a two-sided effect on the carbonation resistance of concrete. The particles of HP-UA had fewer apparent defects. HP-UA formed better particle gradation with cement. Its hydration produced more calcium silicate hydrate and C-S-H gel. [ABSTRACT FROM AUTHOR]

Copyright of Acta Materiae Compositae Sinica is the property of Acta Materiea Compositae Sinica Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Plastics Science & Technology / Suliao Ke-Ji is the property of Plastics Science & Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Chinese Journal of Explosives & Propellants is the property of Chinese Journal of Explosives & Propellants Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Precious Metals / Guijinshu is the property of Precious Metals Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Plastics Science & Technology / Suliao Ke-Ji is the property of Plastics Science & Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Plastics Science & Technology / Suliao Ke-Ji is the property of Plastics Science & Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Cost-effective bamboo strip composite materials have been developed with the low energy consumption, excellent product quality, and high utilization rate, due to the refinement, homogenization, and standardization of bamboo strip. However, there is the low interface compatibility between polar hydroxyl groups on the surface of bamboo strips and non-polar resin matrix. The purpose of this study is to fabricate the structural or sub structural bamboo strips composite materials. The alkali solution was used to treat the bamboo strips for the penetration of resin on the interface and the mechanical properties of composite materials. A systematic investigation was made to clarify the effect of NaOH alkali treatment concentration on the properties of bamboo strips and the epoxy resin composites. The bamboo strips were used as the reinforcement phase, whereas, the epoxy resin as matrix phase. The composites with an average content of 75% bamboo strips were then prepared by hot pressing. Four concentration gradients of NaOH solution were set in the treatment. The properties of bamboo strips and their epoxy resin composites were characterized by means of Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscope (SEM), Thermogravimetric Analysis (TG), and Dynamic Mechanical Analysis (DMA). The experimental results showed that the alkali treatment efficiently removed some impurities, such as lignin, hemicellulose, and wax on the surface of bamboo strips, further to enhance the tensile strength and thermal stability of bamboo strips. SEM results show that the surface fiber morphology of bamboo strips tended to be regular after the proper alkali treatment. Specifically, the fine and smooth microstructure was conducive to the resin penetration. The polarity of bamboo strips first increased and then decreased with the increase of NaOH solution concentration. The crystallinity increased from 60.0% to 63.6% after treatment. The TG analysis demonstrated that there were the lower end degradation temperature of alkali treated bamboo strips, and the lower maximum decomposition rate, indicating the better performance of thermal decomposition. More importantly, the best properties were achieved at the concentration of NaOH solution of 2%, including the tensile property of bamboo strips, the interfacial bonding property with the epoxy resin, and the shear strength. Specifically, the tensile strength of bamboo strips, the shear strength of the composites increased by 52.11%, and 55.24%, respectively. The DMA test results showed that the bamboo strip/epoxy resin composites after the alkali treatment presented the better structural stability under dynamic load in the single frequency (1 Hz) test condition in the range of 30-90 ℃. Once the concentration was 2%, the maximum storage modulus of the bamboo strip/epoxy resin composite was 1.3 times that of the untreated. There was no outstanding difference of storage modulus before and after treatment in the range of 9-140 ℃. A downward trend was found in the loss modulus and loss factor of the composites after alkali treatment in the range of 60-140 ℃. Consequently, the alkali treatment can be expected to enhance the thermal stability and tensile strength of bamboo strips. The interface strength between bamboo strips and epoxy resin was improved, together with the static and dynamic mechanics of bamboo strips reinforced epoxy resin composite resin. The improved composites can also be used in the outdoor agricultural engineering, buildings, and outdoor gardens, in order to reduce the production cost and the comprehensive utilization rate of bamboo strips. [ABSTRACT FROM AUTHOR]

The TC4 dual-phase titanium alloy was cryogenically treated for different times at -196 ℃ by liquid nitrogen direct cooling, and the grain size was characterized by metallurgical microscope; the volume fraction of α and β phases was measured by scanning electron microscope(SEM); Vickers hardness tester and electronic universal testing machine were applied to characterize hardness and tensile properties respectively. Through the change of grain size and the structure of α phase and β phase, the changes of material hardness and tensile properties were carefully explained. The experimental results show that with the extension of the cryogenic time, the grain size gradually decreases, and the volume fraction of the β phase gradually decreases by transforming into the α phase. After 12 h cryogenic treatment, the crystal grains are obviously refined, and the majority of β phase is transformed to the α phase. The samples shows superior comprehensive mechanical performance. When the cryogenic time exceeds 12 h, the volume fraction of the α phase and β phase have no obvious change. After taken out to room temperature, the recovery effect of the samples cryogenic treated over 12 h was more obvious, and the mean grain size was not significantly refined compared with that of the samples treated for 12 h. Consequently, the strength and hardness of the sample treated over 12 h were slightly lower than those of the sample treated at 12 h. In conclusion, the superior comprehensive mechanical properties can be obtained after cryogenic treated for 12 h in liquid nitrogen. [ABSTRACT FROM AUTHOR]

Copyright of Acta Materiae Compositae Sinica is the property of Acta Materiea Compositae Sinica Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Precious Metals / Guijinshu is the property of Precious Metals Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Fly Ash Comprehensive Utilization is the property of Hebei Fly Ash Comprehensive Utilization Magazine Co., Ltd. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Acta Materiae Compositae Sinica is the property of Acta Materiea Compositae Sinica Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Plastics Science & Technology / Suliao Ke-Ji is the property of Plastics Science & Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Plastics Science & Technology / Suliao Ke-Ji is the property of Plastics Science & Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of China Sciencepaper is the property of China Sciencepaper and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Clean Coal Technology is the property of Clean Coal Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Coal Science & Technology (0253-2336) is the property of Coal Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of South China Normal University (Natural Science Edition) / Huanan Shifan Daxue Xuebao (Ziran Kexue Ban) is the property of Journal of South China Normal University (Natural Science Edition) Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The effects of tempering temperatures on microstructure and mechanical properties of the on-line quenched Q690q bridge steel were investigated through optical and scanning electron microscopes and tensile tests. The results show that the microstructure of the on-line quenched steel is primarily the lath bainite. After tempering at 540~650℃, the microstructure is the tempered sorbite. It is also found that with the increase of the tempering temperature, the lath width and the averaged grain size become larger, and the amounts of the carbide precipitations and large-angle grain boundaries increase. Meanwhile, with the tempering temperature increasing, the strength of the tested steel trends to be decreased, in contrast to the plasticity and toughness. At 620℃, the tested steels have the best mechanical properties, in which the yield and tensile strengths are 878 MPa and 992 MPa, the percentage elongation after fracture is 20%, and the impact absorption energy at -40℃ is 143 J. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Harbin University of Science & Technology is the property of Journal of Harbin University of Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In order to evaluate the effects of copper nanoparticles on the chemical structure, thermal properties, crystal structure and mechanical tensile properties of polyamide fibers, both the polyamide fibers containing 0.5% nano-copper and the ordinary polyamide fibers were characterized by scanning electron microscope, Fourier transform infrared spectrometer, X-ray diffraction, thermogravimetric analyzer and differential scanning calorimeter. And the relationship between structure and mechanical tensile properties was also explored. The results show that copper nanoparticles embedded in polyamide matrix did not affect the chemical structure of the fibers. The decomposition of a few small molecules in polyamide fiber can be accelerated by nano-copper. Compared with ordinary polyamide fibers, the primary decomposition of antibacterial polyamide fiber start at a higher temperature, and the residual carbon content is lower. The antibacterial polyamide fiber has higher melting point, crystallization temperature and crystallinity, smaller crystal size, larger crystal surface spacing, higher tensile strength and breaking elongation, while the initial modulus is lower, and the variable coefficients of mechanical properties are larger. [ABSTRACT FROM AUTHOR]

BACKGROUND: How to enhance the mechanical properties of the chitosan-based hydrogels has become a focus in the field of cartilage tissue engineering. In our previous research, chitosan was modified by citric acid, which led to significant improvement in the tensile and compression strength of the modified hydrogen in wet state. OBJECTIVE: To further enhance the mechanical perfonnance of the citric acid modified chitosan hydrogel (i.e., CC) using the cellulose fibers derived from the natural com husk fibers (CHFs), and to explore the potential of CHFs/CC composite hydrogel for cartilage tissue engineering scaffold. METHODS: A freeze-thawing method was employed to prepare CC and CHFs/CC (mass ratios of cellulose fiber to citric acid modified chltosan: 1 :1 and 2:1 ). The structure and mechanical properties of the prepared hydrogels were characterized. Rabbit chondrocytes were seeded onto the hydrogel surface, and the cytocompatibility of the prepared hydrogels was analyzed by live/dead cell staining, CCK-8 assay, and scanning electron microscopy. The ability of CHFs/CC composite hydrogels in promoting functional expression of chondrocytes was determined by collagen immunofluorescence staining and quantitative analysis of glycosaminoglycans. RESULTS AND CONCLUSION: (1) With the increase in CHFs loading fractions, the porosity, equilibrium swelling rate, and degradation rate of CHFs/CC composite hydrogels were gradually reduced, but the compressive strength and Young's modulus in dry and wet states were significantly enhanced. (2) Live/dead cell staining revealed that at 7 days of culture, chondrocytes proliferated well on the surface of three types of hydrogels. (3) The CCK-8 assay showed that with the increase in CHF loading fractions, the proliferative ability of chondrocytes on CC was gradually decreased. (4) Scanning electron microscope revealed that the chondrocytes on CC remained elliptic and were sparsely distributed, whereas most of the chondrocytes on CHFs/CC showed completely spread morphology. (5) After 28 days of culture, with the increase of CHFs loading fractions within CC, the chondrocytes showed gradually decreased expression of type I collagen, gradually increased expression of type II collagen, and there was no significant change in the content of glycosaminoglycans secreted. (6) These results demonstrate a great potential of the CHFs/CC composite hydrogels with good mechanical strength for cartilage tissue engineering scaffold. [ABSTRACT FROM AUTHOR]

Copyright of China Pulp & Paper is the property of China Pulp & Paper Magazines Publisher and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Food Research & Development is the property of Food Research & Development Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Acta Materiae Compositae Sinica is the property of Acta Materiea Compositae Sinica Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In order to make up for the brittleness of Ti-Al intermetallics, TiC/Ti-Al based composites were prepared by SHS/PHIP. The theoretical analysis indicates that the adiabatic temperature increases with increased carbon contents, and the composites can be synthesized when the carbon contents are in excess of or equal to 2%. Scanning electron microscope and X-ray diffraction were used to analyze the products. Results show that ternary phases Ti3AlC and Ti2AlC exist in the synthesized products besides binary Ti3Al and TiAl substrate and strengthening phase TiC. The shape of the strengthening phase changes from granular to claviform and flaky with increased Al contents. The hardness and compression strength of the composites increase with increased carbon contents, whereas the relative density increases initially and decreases subsequently with increased carbon contents. The actual and relative densities reach its maximum when the carbon content is 4%. [ABSTRACT FROM AUTHOR]