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排序方式: 共有252条查询结果,搜索用时 109 毫秒
31.
《低温学》2018
Second-generation high-temperature superconducting (2G HTS) tape is used in magnets and cables because of its outstanding electromagnetic characteristics. However, with the development of winding technology, thinner tapes are required in the construction of magnets. The effect of using thinner substrates on the resulting mechanical and electrical properties of 2G HTS tapes must thus be urgently understood. The interfacial adhesive strength is an important index used to characterize the mechanical strength of 2G HTS tape. Previous experimental studies have shown that thermal stress is one of the major factors in the delamination of the component tape used for magnet winding or cable assembly. In this study, the effect of substrate thickness on the interfacial adhesive strength of 2G HTS tape was investigated using peel test modeling. The thermal residual stresses accumulated during tape synthesis and caused by altered temperature during tape preparation and application at 77 K were also considered. To address the geometrical, physical, and boundary nonlinear problem, the finite element method was used. The simulation results indicate that interfacial stress caused by thermal shrinkage may separate the tape near the superconductor layer at the outer edge; however, no significant effect was observed for the central part. When the thermal residual stress was considered, the peel strength was reduced by approximately 20%. The substrate thickness also played an important role in the magnitude of thermal residual stress, which resulted in an increase of the peel strength with decreasing substrate thickness. 相似文献
32.
采用等通道转角挤压(Equal Channel Angular Pressing, ECAP)并结合热处理制备了Ag/Ti3AlC2复合材料。通过XRD、SEM分析物相和形貌, 探讨了不同热处理条件下Ag/Ti3AlC2材料的电阻率和力学性能。结果表明: 采用ECAP可以明显致密化Ag/Ti3AlC2疏松坯体, 且在ECAP的剪切作用下, 层片状Ti3AlC2颗粒沿基面分层并按一定方向排列。Ti3AlC2的定向排列使材料性能呈现各向异性: 垂直于Ti3AlC2排列方向时, Ag/Ti3AlC2材料的电阻率和压缩强度更高。后续热处理提升了Ag/Ti3AlC2的电阻率和压缩强度, 并发现在800 ℃时增幅显著。这主要归因于Ag与Ti3AlC2在高温下明显增强的界面反应。本研究表明采用ECAP方法可以在致密化Ag/MAX复合材料的同时调控其显微组织, 而结合热处理可以进一步调控界面反应并优化材料性能。 相似文献
33.
Zuming He Hanpei Yang Ngie Hing Wong Lusi Ernawati Jaka Sunarso Zhengyi Huang Yongmei Xia Yong Wang Jiangbin Su Xiaofei Fu Mi Wu 《Small (Weinheim an der Bergstrasse, Germany)》2023,19(18):2207370
Water pollution caused by the massive use of medicines has caused significant environmental problems. This work first reports the synthesis and characterization of the Cu7S4/CuCo2O4 (CS/CCO) yolk–shell microspheres via hydrothermal and annealing methods, and then investigates their photocatalytic performance in removing organic water pollutants. The 10-CS/CCO composite with yolk–shell microspheres exhibits the highest photodegradation rate of carbamazepine (CBZ), reaching 96.3% within 2 h. The 10-CS/CCO also demonstrates more than two times higher photodegradation rates than the pure (Cu7S4) CS and (CuCo2O4) CCO. This outstanding photocatalytic performance can be attributed to the unique yolk–shell structure and the Z-scheme charge transfer pathway, reducing multiple reflections of the acting light. These factors enhance the light absorption efficiency and efficiently transfer photoexcited charge carriers. In-depth, photocatalytic degradation pathways of CBZ are systematically evaluated via the identification of degradation intermediates with Fukui index calculation. The insights gained from this work can serve as a guideline for developing low-cost and efficient Z-scheme photocatalyst composites with the yolk–shell structure. 相似文献
34.
《钢铁研究学报(英文版)》2016,(6):608-617
A new low-cost corrosion-resistant rebar(HRB400R)was designed and fabricated by Cr micro-alloying.The HRB400 Rrebar had uniform distribution of Cr element in ferrite grains.The corrosion behavior of the rebar in the neutral Cl~--containing environment was studied systematically,and the improved corrosion resistance of the HRB400 Rrebar was revealed.According to the corrosion-morphology observation and electrochemical monitoring during the constant immersion corrosion in the 3.5mass% NaCl solution,the HRB400 Rrebar presented alleviated corrosion damage,nobler Ecorr,lower Icorr,and larger Rtvalues,and these phenomena were more remarkable in the initial corrosion period.The elevated electrode potential of the rebar,caused by the solid-solution of Cr micro-alloying in the ferrite grains,was the key to the corrosion-resistance improvement.The HRB400 Rrebar also presented much lower mass-loss rate in the salt spray corrosion test.Besides the elevated corrosion resistance of the matrix,the doping and enrichment of Cr element in the rust layer was another factor for the higher corrosion resistance,which retarded the penetration of aggressive medium through the rust layer. 相似文献
35.
《International Journal of Hydrogen Energy》1998,23(8):653-659
Efficiencies, based on energy and exergy, are comparatively assessed for a wide range of hydrogen production processes, including processes which are
- •• hydrocarbon-based (steam-methane reforming and coal gasification),
- •• non-hydrocarbon-based (water electrolysis and thermochemical water decomposition), and
- •• integrated (steam-methane reforming linked to the non-hydrocarbon-based processes).
36.
《International Journal of Hydrogen Energy》1999,24(2-3):277-282
Gas atomized powders of LaNi2,5Co2,4Al0,1 alloywere prepared and used for the construction of nickel/metal hydride battery. The powdercharacteristics such as particle size distribution, morphology, oxygen content, crystal structure fordifferent fractions were analyzed. The hydriding and electrochemical properties were evaluatedtoo. All fractions have a similar particle morphology and only a slightly different X-ray determinedlattice parameters of the alloy. The fractions with particle size less than 50 μm have apoor activity at both gaseous and electrochemical hydriding. This phenomenon may be attributedto the presence of fine fractions of the amorphous component. Gas atomized powders of coarsefractions possess high corrosion resistance and display a similar hydrogen and electrochemicalcapacity as arc melt alloys. © 1999 Published by Elsevier Science Ltd on behalf of InternationalAssociation for Hydrogen Energy. All rights reserved. 相似文献
37.
Hualin Fan Long Zhao Hailong Chen Ning Kuang Chaokun Yang Shiqing Huang Yifan Jiang 《Composites Science and Technology》2012
To suggest designing instructions for integrated woven textile sandwich composites (IWTSCs), anti-crush properties of IWTSC and the corresponding ductile deformation mechanism were investigated. Quasi-static out-of-plane crushing and dynamic impact tests were carried out. Typical deformation curves with a relative stable deformation plateau were obtained from tests. Failure of IWTSC is ductile through coupled compression–shear deformation. An analytical plastic model was proposed to explain ductile mechanism of IWTSC qualitatively, including densification caused by interactions among inclined piles. Combining with qualitative analysis, comparisons between two kinds of IWTSC panels with piles of different density and thickness reveal the key to design a ductile IWTSC. 相似文献
38.
研究防爆墙迎爆面荷载计算方法有助于防爆墙的科学设计和合理使用。爆炸产生的反射冲击波压力是作用在防爆墙上的主要荷载,由入射压力和与相应的反射压力系数的乘积得到。论文针对墙体变形情况下作用于防爆墙上的反射压力系数的计算方法进行了研究,发现作用于墙体的反射压力系数和墙体变形没有直接关系。基于这一现象,将墙体变形和冲击波墙面反射解耦考虑,提出了反射压力系数的计算方法。论文对比了地面爆炸及近地表空中爆炸对墙体反射压力系数分布规律的差异,建议了近地表空中爆炸时墙体反射压力系数的计算方法。 相似文献
39.
Corrosion behavior of equal-channel-angular-pressed pure magnesium in NaCl aqueous solution 总被引:1,自引:0,他引:1
Effect of microstructure change on corrosion behavior of equal-channel-angular-pressed (ECAPed) pure Mg was investigated. The ECAPed sample after 6 passes obtained finer grains (50-100 μm) compared with as-cast one (800-1500 μm). The strain-induced grain refinement with more crystalline defects weakened corrosion resistance of pure Mg, resulting in more and deeper pits after in-situ corrosion, higher mass-loss rate immersed in NaCl solution, larger Icorr values in polarization curves and lower fitted Rt values in EIS plots. However, the enhanced initial OCP values indicate better weather resistance. Furthermore, corrosion improvement can be expected by reducing defects via subsequent annealing. 相似文献
40.
Jianli Wang Bai Song Ming Gu Xing Zhang 《International Journal of Heat and Mass Transfer》2010,53(23-24):5350-5354
Temperature dependence of thermal resistance of a bare joint between two crossed platinum wires was measured using a quasi steady-state T-type probe in the temperature range of 100–300 K. The thermal resistance was found to decrease rapidly as the temperature increased from 100 to 200 K, then the trend slowed down, which could be explained by the temperature behaviors of the hardness and elastic modulus of platinum. Considering both the microscopic and macroscopic thermal resistances, the calculated results fitted well with the experimental data, and the obtained conductance–load exponent was also within the reasonable range. 相似文献