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991.
在一定温度条件下,用氨基硅油对苎麻纤维进行表面改性处理.利用红外光谱分析(IR)、接触角测试、X射线衍射分析(XRD)、热重分析(TG)等方法对改性前后苎麻纤维的性能进行分析.结果表明,经氨基硅油改性的苎麻纤维表面成功包覆了有机硅分子,且表面羟基数量减少,吸水性较未改性的苎麻纤维下降,与聚丙烯相容性提高;改性后,苎麻纤维的结晶度提高了15%;在230℃以前,未改性的苎麻纤维质量损耗为5%,而改性后苎麻纤维基本上没有分解,改性后苎麻纤维的耐热性能有了较大的提高。 相似文献
992.
斜拉桥拉索表面形成的覆冰可能会使斜拉索发生不稳定的驰振振动.首先,制作了6种覆冰截面的拉索模型,几何缩尺比为1∶1;然后,进行了静力天平测力风洞试验,得到了6种覆冰截面的平均升力系数和平均阻力系数,并给出了驰振力系数;最后,采用Fluent软件模拟了2种覆冰截面的绕流情况,并给出了平均升力系数.结果表明:上述6种覆冰截面的驰振力系数均远小于零,存在发生驰振的可能性;CFD模拟得到的平均升力系数与试验结果吻合较好. 相似文献
993.
通过两端固结梁和两端铰接梁的频率特征方程,在找出了二者的频率关系后,建立了一个形式简单、物理意义明确的索力计算公式.和同类方法的对比分析结果表明,该公式具有更好的计算精度和适用范围,使用该公式可以快速、准确地识别出不同长细比、抗弯刚度拉索的索力.分析了拉索边界条件对索力计算结果的影响,提出了考虑拉索端部转动约束刚度的索力计算公式. 相似文献
994.
ZHENG Qi~ CAO Qihua~ LIU Zhihong~ CAI Ruxiu~ . College of Chemistry Environmental Engineering Jianghan University Wuhan Hubei China . College of Chemistry Molecular Sciences Wuhan University Wuhan Hubei China 《武汉大学学报:自然科学英文版》2006,11(3):677-681
0 IntroductionSltougdiiceasl csoynstceermnsin gharveeac btieveen o txhyeg ei nm psopretcaienst ( oRbjOecSt) iinn bbiioo--medicine and analytical chemistry in recent years[1-4]. Manyi mportant life phenomena and diseases are relatedtotheinter-mediates of ROS[5-7].ROS have beeni mplicated as ani mpor-tant causative factor in cell damage,including apoptosis andnecrosis . Their proposed actions comprise lipid peroxidation,DNAdamage,the mitochondrial respiratory chain destructionand protein mo… 相似文献
995.
XU Kuoxi HU Peizhi~ CAI Lihua College of Chemistry Molecular Sciences Wuhan University Wuhan Hubei China 《武汉大学学报:自然科学英文版》2006,11(3):682-686
0 IntroductionPayrriodminaetiics hoenteer oofc ythcleics m .os tC oambupnoduanndts a cnodn tbaeisntin kgno twhnepyridine ring are widely distributedin nature,principally asenzymes and alkaloids . Pyridine enzymes have been foundintissues of all plants and ani mals examined thus far ,andare derivedfromeither nicotinic acid or Vitamin B6[1].Pyr-idine derivatives are also the building block of many phar-maceuticals with a wide range of functionalities that includeantitubercular compounds ,antivi… 相似文献
996.
WANG Sheng XIONG Qian JIANG Ai-ping XIA Ying-qing XU Peng-gen . School of Electronic Information Wuhan University Wuhan Hubei China . School of Physics Technology Wuhan University Wuhan Hubei China . College of Physical Science Technology Huazhong Normal University Wuhan Hubei China 《武汉大学学报:自然科学英文版》2005,10(2):410-412
,,,.lr.0 IntroductionThe RCS(Radar Cross Section) of a target in the near zone is very important in the various civilian and militaryfields. For a complex target, we dissect it in the near zone tomany small regions and simulate the RCS of the the whole … 相似文献
997.
CHEN Juan LI Hong-lian FENG You-mei WANG Jian-zhi .Department of Biochemistry Molecular Biology Tongji Medical College Huazhong University of Science Technology Wuhan China .Department of Pathophysiology Tongji Medical College Huazhong University of Science Technology Wuhan China 《武汉大学学报:自然科学英文版》2005,10(2)
0 IntroductionNeurofibrillary tangle, primarily composed of thehyperphosphorylated microtubule associatedprotein tau[1], is one of the major neuropathologichallmarks in Alzheimar’s disease (AD). In affectedneurons, the major mechanism o… 相似文献
998.
HU Yao-jun~ WEI Lei~ LIU Shu-nan~ YU Jin-hong~ DING Yi~ . Key Laboratory of MOE for Plant Developmental Biology/College of Life Sciences Wuhan University Wuhan Hubei China . College of Life Sciences Hunan University of Science Technology Xiangtan Hunan China . College of Life Sciences Huazhong Normal University Wuhan Hubei China 《武汉大学学报:自然科学英文版》2005,10(3)
0Introduction Malesterilityisacomplicatedphenomenoninhigherplants,whichestablishesthebiologicalbasisofhetero sisutilizationincropsbreeding,especiallyinrice(Oryzasati vaL.).Themolecularandphysiologicalresearchinplantmalesterility,especiallythediscoveryofth… 相似文献
999.
TAO Ning WU Xu-feng QIU Xiao-ping ZHAO Min TAN Yun WU Xin-xing . Institute of Virology Medical School Wuhan University Wuhan Hubei China . Department of Oncology Zhongnan Hospital Wuhan University Wuhan Hubei China 《武汉大学学报:自然科学英文版》2005,10(4):759-766
0Introduction Cervicalcarcinomaisoneofprevalentmalignancy,itisthesecondmostcommoncancerofwomenintheworld wide(thefirstisbreast cancer).Itisestimatedthatthereare450000newcasesinworldeveryyear,ofwhich80%arein developingcountries.Thereare135000newcasesinChin… 相似文献
1000.
Ni Bin |bin Zhao Zheng |yu Xie Shu |guo School of Electronic Information Wuhan University Wuhan Hubei China 《武汉大学学报:自然科学英文版》2003,8(3):847-852
0 IntroductionIthasbeenwellknownthattheformationofIonosphericAlfv啨nResonator(IAR)isforthebreakdownofgeometricop tics.ItscentralregionliesneartheheightofF regionelectrondensitypeak .Andatthetypicalheightof 30 0 0kmexiststhemaximumgradientofAlfv啨nvelocity ,whichleadstothereflec tionofshearAlfv啨nwavesandproducestheupperboundaryoftheresonator.Likewise,thelowerboundaryoftheresonatorformsneartheheightof 2 0 0 30 0km .Thus,she… 相似文献