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ClnOPodiumpoIycePhalum(VantjCYWhetHsuancalled'DuanXielin'inChineseisusedinfolkmedicineforthetreatInentofhaemorrhagiadisease.lInordertofmdtheactivecomPounds,studiesonthechedricalconstituentsofthewholeplan,collectedatHuoShanofAnhuiprovince,werecarriedout.Fromthealcoholicextracts,wehaveisolatedanewanthraquinone,Glyceroyl-l,6,8-trihydroxy-3-methyl-9)lO-dioxo-2-anthrcenecarboxylateI(Figurel).Iwasobtainedasredneedles,mP:ll9-l2l"C.TheHR-MSdareaffordedthefor-mulaasCl9Hl6O9(Found388.O791;… 相似文献
84.
液晶性芳香酰胺化合物的合成 总被引:7,自引:0,他引:7
合成了一系列炖粹以酰胺基为中心桥键的刚性芳香酰胺小分子化合物,并对其作了表征,发现其中有些化合物具有液晶性。酰胺键之间能形成很强的分子间氢键,使芳香酰胺小分子化合物的熔点很高,难于形成液成液晶态。研究发现,如果在这类化合物的中心苯环上引入合适的取代基以减弱分子间氢键,同时引入合适的末端基时,则可使芳香酰胺化合物生成液晶相的能力增强。 相似文献
85.
A physical model of series of the conductivity on chain and the interchain conductivitybetween chains is proposed to explain enhanced conductivity of stretched conducting polymers.This model suggests that the enhanced conductivity for stretched conducting polymers might bedue to increasing of the interchain conductivity between chains along the elongation direction afterdrawing processes if the conductivity on chain is assumed much larger than that of the interchainconductivity between chains. According to this model, it is expected that the temperaturedependence of conductivity measured by four-probe method for stretched conducting polymers iscontrolled by a variation of the interchain conductivity between chains with temperature, whichcan be used to explain that a metallic temperature dependence of conductivity for stretchedconducting polymers is not observed although the conductivity along the elongation direction isenhanced by two or three orders of magnitude. 相似文献
86.
Effect of different alkali metal salts on the crystal size and the crystallization rate of ZSM-5 zeolite was de-tailedly investigated in this paper. The samples prepared by adding the different alkali metal salts were character-ized by using XRD, TEM, TG-DSC, BET and IR techniques. The XRD results showed that, for the nanosized ZSM-5 zeolite, the characteristic peaks broadened on the XRD patterns in comparison with the microsized ZSM-5 zeolite. The SEM results verified that the crystal size of zeolites prepared by adding different alkali metal salts had different results, and adding NaCl, NaC2H3O2 and KCl showed the better effect of reducing crystal size, which are about of 40~60nm size. The crystallization curve of adding the different alkali metal salts suggested that the crystallization rate was significantly affected by the anions in the alkali metal salt besides the cations. Moreover, the crystal size likewise depended on the anion in the alkali metal salt. In addition, the BET results suggested that the nanosized ZSM-5 zeolite possessed a larger outer surface area in comparison with the microsized ZSM-5 zeolite. The thermostability of the samples was determined by TG-DSC technique, indicating that the nanosized ZSM-5 zeolite had a poor thermostability as compared with the microsized ZSM-5 zeolite. The possible difference of the samples with different crystal sizes on IR spectra was also given. 相似文献
87.
基于参考光栅的光纤光栅应变传感器温度补偿 总被引:6,自引:8,他引:6
为解决光纤布拉格光栅(FBG)应变测量时的应变、温度交叉敏感问题,利用FBG便于构成传感网络的优点,将温度补偿参考FBG与应变测量FBG串联在一路光纤上,根据2只FBG布拉格波长相对漂移获得被测结构应变。双FBG波长相对漂移对温度的灵敏度仅为0.12pm/℃,较好地实现FBG应变测量的温度补偿。参考FBG法原理简单,可操作性强,为FBG应变传感器的实际工程应用奠定了基础。 相似文献
88.
考虑电子对抗的作战特点,遵循体系构建原则,依据作战目标特性,以作战规模为依据,把电子对抗装备战术指标划分为战略、战役、战术三个层次,并把作战规模作为一级指标的划分依据,选择作战用途和装备指标性质作为二级指标的划分依据,装备的具体作战能力和环境适应能力作为三级以下指标划分依据。 相似文献
89.
JIA HongSheng JIA XiaoPeng XU Yue WAN LianRu JIE KaiKai & MA HongAn State Key Laboratory of Superhard Materials Jilin University Changchun China Test Science Experiment Center Changchun 《中国科学:物理学 力学 天文学(英文版)》2011,(1)
Polycrystalline diamond compacts (PDC) were synthesized using diamond powder of average crystal size 3-20 μm by the Ni 70 Mn 25 Co 5 alloy infiltration technique at high temperature and high pressure (HPHT).The surface residual stress of polycrystalline diamond (PCD) layer was measured using micro-Raman spectroscopy with hydrostatic stress model and X-ray diffraction (XRD).Measurements of the stress levels of PCDs show that the residual compressive stresses range from 0.12 to 0.22 GPa,which increase with th... 相似文献
90.
As Reduced Activation Ferritic/Martensitic (RAFM) steel is considered the primary candidate for use as a structural material in fusion power reactors,many countries are developing different kinds of RAFM.China is developing new CLAM (China Low Activation Martensitic) steel.The study investigates microstructural changes in CLAM steel implanted with deuterium ions induced by 1250 keV electron irradiation from R.T.to 873 K,and observes both the growth and shrinkage of the defect clusters produced by deuterium ... 相似文献