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《汉语大词典》“末界”释义考辨
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作者 李玉平 《励耘语言学刊》 2007年第1期41-50,共10页
《汉语大词典》将所举用例中的"末界"释为"指与人类相对而言的动物界"有误,当从宋代李如篪《东园丛说》中的观点,释为"边界,边境"。而且《汉语大词典》中"末界"释义所列义项也不全面,还应补充三个义项:1.表示弧线、直线或直线... 《汉语大词典》将所举用例中的"末界"释为"指与人类相对而言的动物界"有误,当从宋代李如篪《东园丛说》中的观点,释为"边界,边境"。而且《汉语大词典》中"末界"释义所列义项也不全面,还应补充三个义项:1.表示弧线、直线或直线状物的末端、终端。2.指末带(地球上南北各二十三度至两极下的地带)的边界,即南北极圈。3.比喻失意没落的境地。 展开更多
关键词 《汉语大词典》 末界
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Low frequency damping behavior associated with sintering process in Al powder compact
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作者 郝刚领 李先雨 王伟国 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2016年第4期1176-1182,共7页
The internal friction behavior of Al green power compact duxing the sintering process was studied as a function of temperature. The internal friction measurements were performed from room temperature to 600 °C. T... The internal friction behavior of Al green power compact duxing the sintering process was studied as a function of temperature. The internal friction measurements were performed from room temperature to 600 °C. Two typical internal friction peaks were detected corresponding to heating and cooling processes, respectively. The heating peak corresponds to a recrystallization process of deformed Al particles, which is influenced by many extrinsic parameters, such as measuring frequency, strain amplitude, heating rate, power particle size and compacting pressure. However, the intrinsic nature of the peak is originated from the micro-sliding of the weak-bonding interfaces between Al particles and increased dislocation density induced in compressing. The cooling peak with the activation energy of (1.64±0.06) eV is associated with the grain boundary relaxation, which can be interpreted as the viscous sliding of grain boundaries. The similar phenomena are also found in the Mg green powder compact. 展开更多
关键词 Al powder compact internal friction SINTERING grain boundary
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Preparation and properties of graphene nanoplatelets reinforced aluminum composites 被引量:5
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作者 Zhong ZHENG Xiao-xia YANG +3 位作者 Jian-chao LI Xue-xi ZHANG Imran MUHAMMAD Lin GENG 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2021年第4期878-886,共9页
5.0 vol.% graphene nanoplatelets(GNPs) and aluminum powders were mixed to prepare GNPs/Al composites via high-energy ball milling(HEBM). The mixed powders were subjected to spark plasma sintering(SPS) and subsequent h... 5.0 vol.% graphene nanoplatelets(GNPs) and aluminum powders were mixed to prepare GNPs/Al composites via high-energy ball milling(HEBM). The mixed powders were subjected to spark plasma sintering(SPS) and subsequent hot extrusion. The microstructure and mechanical properties of extruded composites were investigated by X-ray photoelectron spectroscopy(XPS), transmission electron microscopy(TEM) and tensile tests. In the extruded composites, 5.0 vol.% GNPs were dispersed homogeneously and no serious GNP-Al interfacial reaction occurred. As a result, the yield strength and ultimate tensile strength of the extruded GNPs/Al composites reached 462 and 479 MPa, which were 62% and 60% higher than those of the extruded Al matrix, respectively. The enhanced mechanical properties were attributed to the effective load transfer capacity of dispersed GNPs. This demonstrated that it may be promising to introduce dispersed high-content GNPs via HEBM, SPS and hot extrusion techniques and GNP-Al interfacial reaction can be controlled. 展开更多
关键词 aluminum matrix composites graphene nano-platelets powder metallurgy interface microstructure mechanical properties
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Microstructures and mechanical properties of Al 2519 matrix composites reinforced with Ti-coated SiC particles 被引量:8
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作者 Cui-ge DONG Rui CUI +2 位作者 Ri-chu WANG Chao-qun PENG Zhi-yong CAI 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2020年第4期863-871,共9页
Ti-coated SiCp particles were developed by vacuum evaporation with Ti to improve the interfacial bonding of SiCp/Al composites.Ti-coated SiC particles and uncoated SiC particles reinforced Al 2519 matrix composites we... Ti-coated SiCp particles were developed by vacuum evaporation with Ti to improve the interfacial bonding of SiCp/Al composites.Ti-coated SiC particles and uncoated SiC particles reinforced Al 2519 matrix composites were prepared by hot pressing,hot extrusion and heat treatment.The influence of Ti coating on microstructure and mechanical properties of the composites was analyzed by scanning electron microscopy(SEM)and energy dispersive spectroscopy(EDS).The results show that the densely deposited Ti coating reacts with SiC particles to form TiC and Ti5Si3 phases at the interface.Ti-coated SiC particle reinforced composite exhibits uniformity and compactness compared to the composite reinforced with uncoated SiC particles.The microstructure,relative density and mechanical properties of the composite are significantly improved.When the volume fraction is 15%,the hardness,fracture strain and tensile strength of the SiCp reinforced Al 2519 composite after Ti plating are optimized,which are HB 138.5,4.02%and 455 MPa,respectively. 展开更多
关键词 Al 2519 matrix composites surface modification Ti-coated SiCp powder metallurgy interfacial microstructure mechanical properties
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Clinical applications of hepatocyte transplantation 被引量:23
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作者 Giada Pietrosi Giovanni Battista Vizzini +1 位作者 Salvatore Gruttadauria Bruno Gridelli 《World Journal of Gastroenterology》 SCIE CAS CSCD 2009年第17期2074-2077,共4页
The shortage of organ donors is a problem worldwide, with approximately 15% of adult patients with lifethreatening liver diseases dying while on the waiting list. The use of cell transplantation for liver disease is a... The shortage of organ donors is a problem worldwide, with approximately 15% of adult patients with lifethreatening liver diseases dying while on the waiting list. The use of cell transplantation for liver disease is an attempt to correct metabolic defects, or to support liver function as a bridge to liver transplantation and, as such, has raised a number of expectations. Most of the available studies briefly reported here focus on adult hepatocyte transplantation (HT), and the results are neither reproducible nor comparable, because the means of infusion, amount of injected cells and clinical variability differ among the studies. To better understand the specif ic role of HT in the management of end-stage liver disease, it is important that controlled studies, designed on the principles of evidence-based medicine, be done in order to guarantee the reproducibility of results. 展开更多
关键词 Hepatocyte transplantation Metabolic dis-eases Chronic liver disease Liver failure Stem cells
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Improving performance of recycled aggregate concrete with superfine pozzolanic powders 被引量:3
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作者 王海龙 王俊杰 +1 位作者 孙晓燕 金伟良 《Journal of Central South University》 SCIE EI CAS 2013年第12期3715-3722,共8页
Phosphorous slag (PHS), ground granulated blast-furnace slag (GGBS) and fly ash (FA) were used as replacements of Portland cement to modify the microstruc^xe of recycled aggregate concrete (RAC). A new manufac... Phosphorous slag (PHS), ground granulated blast-furnace slag (GGBS) and fly ash (FA) were used as replacements of Portland cement to modify the microstruc^xe of recycled aggregate concrete (RAC). A new manufacturing method named "W3T4" was proposed to improve the performances of interracial transition zone (ITZ) between recycled aggregate and mortar. The mechanical properties and the durability of RAC were tested, which show that this new manufacturing method improves the properties of RAC, and the GGBS with finest size makes a great contribution to the performance of RAC due to its better filling effect and much earlier pozzolanic reaction. Combined with GGBS, the effects of PHS on the retardation of setting time can be alleviated and the synergistic effect helps to make a more compact RAC. For the RAC with 25% of the recycled aggregate (RA) replacement and 10% PHS + 10% GGBS additives, the compressive strength increases by 25.4%, but the permeability decreases by 64.3% with respect to the reference concrete made with nature aggregates. The micro-mechanisms of these improvements were investigated by the scanning electron microscope (SEM). The SEM images show that the new manufacturing method, adding superfine pozzolanic powders and super-plasticizer benefits, makes a much denser ITZ in RAC. 展开更多
关键词 recycled aggregate concrete superfine pozzolanic powders manufacturing method DURABILITY MICROSTRUCTURE
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