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钨触头在电器中的应用
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作者 H.Kippenberg 《中国钨业》 CAS 1997年第Z1期52-54,共3页
许多用于大电流和高电压电路的开关都装配有高熔点的含钨的电接触材料,以确保良好的抗电弧性能和较长的使用寿命。常用的接触材料为导电性能好的金属银和铜,在特殊情况下应用WCAg材料,这些复合材料用粉末冶金法制造,最好采用烧结和渗入... 许多用于大电流和高电压电路的开关都装配有高熔点的含钨的电接触材料,以确保良好的抗电弧性能和较长的使用寿命。常用的接触材料为导电性能好的金属银和铜,在特殊情况下应用WCAg材料,这些复合材料用粉末冶金法制造,最好采用烧结和渗入法制备。为经受电弧应力,要求采用细小颗粒组分的分布很均匀的高品级原料。 展开更多
关键词 接触件 断电器 电接触材料 瞬态放电 复合材 粉末冶金法 使用寿命 低压电路 低压接触器 辅助组分
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Computer aided modeling and pore distribution of bionic porous bone structure 被引量:5
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作者 李虎 杨建宇 +1 位作者 苏鹏程 王宛山 《Journal of Central South University》 SCIE EI CAS 2012年第12期3492-3499,共8页
Artificial bone with porous structure is crucial for tissue scaffold and clinic implants.Scaffold provides structure support for cells and guides tissues regeneration for final tissue structure.A computational aided p... Artificial bone with porous structure is crucial for tissue scaffold and clinic implants.Scaffold provides structure support for cells and guides tissues regeneration for final tissue structure.A computational aided process of porous bone modeling was developed which described the design and fabrication of tissue scaffolds by considering intricate architecture,porosity and pore size.To simulate intricate bone structure,different constructive units were presented.In modeling process,bone contour was gotten from computed tomography(CT)images and was divided into two levels.Each level was represented by relatively reconstructive process.Pore size distribution was controlled by using mesh generation.The whole hexahedral mesh was reduced by unit structure,when a 3D mesh with various hexahedral elements was provided.The simulation results show that constructive structure of porous scaffold can meet the needs of clinic implants in accurate and controlled way. 展开更多
关键词 tissue scaffold geometry modeling porous structure compute aided design optimal design clinic implants
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Proteomic analysis of pancreatic intraepithelial neoplasia and pancreatic carcinoma in rat models 被引量:8
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作者 Lei Wang Hai-Lin Liu +1 位作者 Ya Li Ping Yuan 《World Journal of Gastroenterology》 SCIE CAS CSCD 2011年第11期1434-1441,共8页
AIM:To detect the proteomic variabilities of pancreatic intraepithelial neoplasia(PanIN)and pancreatic carcinoma(PC)induced by 7,12-dimethylbenzanthracene(DMBA) in rat models and to identify potential biomarkers.METHO... AIM:To detect the proteomic variabilities of pancreatic intraepithelial neoplasia(PanIN)and pancreatic carcinoma(PC)induced by 7,12-dimethylbenzanthracene(DMBA) in rat models and to identify potential biomarkers.METHODS:Sixty adult male Sprague Dawley rats were randomized into three groups.The rats had DMBA implanted into their pancreas for one(n=20)or two months(n=20)or assigned to the normal group(n =20).The rats were killed after one or two months,and were evaluated histopathologically.Three tissue samples from each group of rats with either normal pancreas,PanIN(PanIN-2)or PC were examined by 2D-DIGE.The different expression spot features were analyzed by matrix-assisted laser desorption/ionizationtime of flight/time of flight(MALDI-TOF/TOF)tandem mass spectrometry.The expression of enolase 1,a differentially expressed protein,was identified by immu-nohistochemistry.RESULTS:There was significant difference in the proportions of neoplastic changes between the 1-and 2-mogroups(P=0.0488).There was an increase in the frequency of adenocarcinomas in the 2-mo group compared with the 1-mo group(P=0.0309).No neoplastic changes were observed in any of the animals in the normal group.Enolase 1,pancreatic ELA3B,necdin,Hbp23,CHD3,hnRNP A2/B1,Rap80,and Gnb2l1 were up-regulated in the PanIN and PC tissues,and CEL,TPT1,NME2,PCK2,an unnamed protein product,and glycine C-acetyltransferase were down-regulated in the PanIN and PC tissues.The immunohistochemical results showed that enolase 1 expression was up-regulated in the pancreatic cancer tissues of rats and humans.CONCLUSION:The pancreatic protein expression changes induced by DMBA suggest potential molecular targets for the early diagnosis and treatment of PC. 展开更多
关键词 7 12-dimethylbenzanthracene Pancreatic intraepithelial neoplasia Pancreatic carcinoma PROTEOMICS
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Microwave Assisted One-Pot Preparation of Quinoline Derivatives without any Solvent According to Green Chemistry
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作者 Behrooz Mirza Sepehr Sadegh Samiei 《Journal of Chemistry and Chemical Engineering》 2011年第7期644-647,共4页
The convenient and efficient procedure for one-pot preparation of quinaldine derivatives from multi component reaction of anilines, acetone and benzaldehyde without any solvent under microwave irradiation on the surfa... The convenient and efficient procedure for one-pot preparation of quinaldine derivatives from multi component reaction of anilines, acetone and benzaldehyde without any solvent under microwave irradiation on the surface of alumina impregnated with hydrochloric acid is developed. 展开更多
关键词 MCRS quinoline derivatives ONE-POT microwave SOLVENT-FREE green chemistry.
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SiO_2、Al_2O_3和Fe_2O_3对静态破碎剂性能的影响 被引量:2
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作者 汪智勇 陈旭峰 《膨胀剂与膨胀混凝土》 2017年第1期2-7,共6页
本文研究了SiO_2、Al_2O_3和Fe_2O_3对二相体系静态破碎剂的凝结时间、膨胀压及水化温升等性能的影响。研究结果表明,不同辅助组分的静态破碎剂性能特占大不相同。以SiO_2和Al_2O_3为辅助组分的静态破碎剂凝结时间较短,早期膨胀压增长迅... 本文研究了SiO_2、Al_2O_3和Fe_2O_3对二相体系静态破碎剂的凝结时间、膨胀压及水化温升等性能的影响。研究结果表明,不同辅助组分的静态破碎剂性能特占大不相同。以SiO_2和Al_2O_3为辅助组分的静态破碎剂凝结时间较短,早期膨胀压增长迅速,尤其是Al_2O_3为辅助组分的静态破碎剂。以Fe_2O_3为辅助组分的静态破碎剂凝结时间较长,膨胀压增长较为缓慢。辅助组分对静态破碎剂性能的影响主要是由于在高温下与CaO反应生成了不同的辅助矿物,这些辅助矿物高温及水化特性影响了主要矿物f-CaO的水化反应从而导致对性能的影响。辅助组分对静态破碎剂的性能影响的规律,对于指导开发适应不同环境和需要的新型号静态破碎剂及现有产品性能改进有重要指导意义。 展开更多
关键词 静态破碎剂 辅助组分 辅助矿物 性能
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Cryopreservation of mammalian oocytes and embryos: current problems and future perspectives 被引量:20
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作者 MOUSSA Mahmoud SHU Juan +1 位作者 ZHANG XueHong ZENG FanYi 《Science China(Life Sciences)》 SCIE CAS 2014年第9期903-914,共12页
Cryopreservation techniques for mammalian oocytes and embryos have rapidly progressed during the past two decades,emphasizing their importance in various assisted reproductive technologies.Pregnancies and live births ... Cryopreservation techniques for mammalian oocytes and embryos have rapidly progressed during the past two decades,emphasizing their importance in various assisted reproductive technologies.Pregnancies and live births resulting from cryopreserved oocytes and embryos of several species including humans have provided proof of principle and led to the adoption of cryopreservation as an integral part of clinical in vitro fertilization.Considerable progress has been achieved in the development and application of the cryopreservation of mammalian oocytes and embryos,including preservation of the reproductive potential of patients who may become infertile,establishment of cryopreserved oocyte banks,and transport of oocytes and embryos internationally.However,the success rates are still far lower than those obtained with fresh oocytes and embryos,and there are still obstacles that need to be overcome.In this review,we address the major obstacles in the development of effective cryopreservation techniques.Such knowledge may help to eliminate these hurdles by revealing which aspects need improvement.Furthermore,this information may encourage further research by cryobiologists and increase the practical use of cryopreservation as a major part of assisted reproductive technologies for both humans and animal species. 展开更多
关键词 CRYOPRESERVATION MAMMALS OOCYTES embryos cryoinjuries
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Quantitative analysis of diffusion-weighted magnetic resonance images:differentiation between prostate cancer and normal tissue based on a computer-aided diagnosis system 被引量:13
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作者 Ge Gao Chengyan Wang +5 位作者 Xiaodong Zhang Juan Hu Xuedong Yang He Wang Jue Zhang Xiaoying Wang 《Science China(Life Sciences)》 SCIE CAS CSCD 2017年第1期37-43,共7页
Diffusion-weighted imaging(DWI) is considered to be one of the dominant modalities used in prostate cancer(PCa) detection and the assessment of lesion aggressiveness,especially for peripheral zone(PZ) PCa.Computer-aid... Diffusion-weighted imaging(DWI) is considered to be one of the dominant modalities used in prostate cancer(PCa) detection and the assessment of lesion aggressiveness,especially for peripheral zone(PZ) PCa.Computer-aided diagnosis(CAD),which is capable of automatically extracting and evaluating image features,can integrate multiple parameters and improve the detection of PCa.In this study,13 quantitative image features were extracted from DWI by CAD,and diagnostic efficacy was analyzed in both the PZ and transition zone(TZ).The results demonstrated that there was a significant difference(P<0.05) between PCa and non-PCa for nine of the 13 features in the PZ and five of the 13 features in the TZ.Besides,the prediction outcome of CAD had a strong correlation with the DWI scores that were graded by experienced radiologists according to the Prostate Imaging-Reporting and Data System Version 2(PI-RADS v2). 展开更多
关键词 prostate cancer magnetic resonance imaging DWI diagnosis COMPUTER-ASSISTED prostate imaging-reporting and datasystem (PI-RADS)
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High-throughput development of genome-wide locus-specific informative SSR markers in wheat 被引量:4
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作者 Lei Li Fayu Sun +4 位作者 Di Wu Fei Zhen Guihua Bai Derong Gao Tao Li 《Science China(Life Sciences)》 SCIE CAS CSCD 2017年第6期671-673,共3页
Dear Editor,Although simple sequence repeat(SSR)markers are not new,they are still useful and often used markers in molecular mapping and marker-assisted breeding,particularly in developing countries.However,locus-s... Dear Editor,Although simple sequence repeat(SSR)markers are not new,they are still useful and often used markers in molecular mapping and marker-assisted breeding,particularly in developing countries.However,locus-specific SSR markers could be more useful and informative in wheat breeding and genetic studies.In the present study,221,911 locus-specific SSR markers were designed.Verification of polymorphisms showed that the proportion of polymorphic markers increases with an increase in SSR size. 展开更多
关键词 locus wheat informative breeding polymorphic throughput SSRs Aegilops primer Triticum
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