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1.
聚乙二醇蓄热调温性能及其在功能纺织品上的应用   总被引:13,自引:1,他引:12  
对聚乙二醇(PEG)的自身交联及其与纤维素纤雏之间的交联反应进行了研究,探讨了交联前后PEG热活性的变化,并对PEG在焙烘交联时的受热稳定性以及分子量对热活性的影响进行了讨论。研究表明,PEG发生交联反应后,热性能参教产生偏移,热活性降低;热活性与分子量有直接关系;过高的焙烘温度将导致PEG氧化降解,热活性下降。在适宜的工艺条件下,纺织品经PEG后整理可获得热活性。  相似文献
2.
傅承光  徐宏达 《色谱》1995,13(5):365-367
 研究了适于分离检测四环素类药物的高效液相色谱荧光检测方法。为提高分析灵敏度,使用了柱后调节pH技术。探讨了pH以及胶束浓度对荧光强度的影响。四种药物的检出限达8.0~75.6pg的水平。  相似文献
3.
AGE-DEPENDENT LOGISTIC REGRESSION MODEL AND ITS APPLICATION   总被引:1,自引:0,他引:1  
In the present paper we introduce the theory and algorithm of the unconditional and con-ditional age-dependent logistic regression model, which combines logistic regression analysisof case-control study with survival analysis of cases in the data, thus facilitating simulta-neous comparison analysis between cases and controls and among cases with different ages ofdisease onset under study. In age-dependent logistic regression analysis, estimated compoundrelative risk (CRR) and compound attributable risk (CAR)comprise the variance contribu-tions of risk factors to disease occurrence and the time of disease onset, thereby the roleplayed by various risk factors in etiology and etiopathology can be objectively evaluated.The current logistic regression model is only a particular case of age-dependent logistic re-gression theory neglecting the variations in onset age of diseases.  相似文献
4.
通过对广义簇合物生长的自调整模型的解析,得出了粒子在均匀几率密度场下簇合物生长形态的变化特征,揭示了表征其生长形态结构分式维数D的物理意义,同时考查了格子模型对簇合物生长形态的影响以及自调整模型的动力学行为。  相似文献
5.
模拟透射电镜双倾台进行样品位向调整过程,推导出反映样品倾转前后其合成倾转轴(即共有菊池线对的法线)方向变化规律的计算公式,称为附加旋转角计算公式。指出,实现样品位向调整的双倾操作,等效于样品绕其合成倾转轴的倾转及该倾转轴绕Z轴(平行入射束方向)的旋转之和。利用双倾台对薄膜样品进行的系列倾转实验表明,由附加旋转角公式计算的附加旋转角和实测值相一致。还根据双倾操作过程导出了合成倾转角的计算公式,它可用于判断样品位向调整的准确度。  相似文献
6.
The active conformation is part of a conformational mixture with experimental activity Yexp, and is used in QSAR studies to extract more information regarding the ligand-receptor interaction. To reflect the relative amount () of the active conformation, we adjust Yexp : Yadj = Yexp - log . We establish a quantitative structure-activity relationship (QSAR) between Yadj and 3D conformational characteristics for the acetylcholinesterase (AChE) hydrolysis rates of 25 acetic esters. The 3D-QSAR model was obtained using the adjusted multiconformational minimal steric/topologic difference (MTD-ADJ) method, optimizing the receptor map based on Yadj for each conformer. Yadj was updated during each step of the optimization process. and Yadj are based on the Boltzmann distribution calculated using AM1 (MOPAC 6.0) relative energies of the COSMIC 90 derived conformers. The MTD-ADJ results are: (i) the 3D-QSAR models obtained by this procedure have significant statistical parameters and are similar to the unadjusted (MTD-MC, using Yexp) models; (ii) the selected bioactive conformations are extended, occupy cavity vertices and, for the same structures, have the same MTD value; and (iii) the optimized conformational map of the neutral ligands obtained from the MTD-ADJ model fits well in the active site of the crystallographic structure of AChE (from Torpedo californica). We propose a neutral ligands binding site model for AchE. Our results show that MTD-ADJ, which can be implemented in any 3D-QSAR method, is capable of providing additional information regarding the active conformations, and can be used to gain further insight into the ligand-receptor models for which no structural data are available.  相似文献
7.
首先用溶胶-凝胶法制备符合SrAl2O4:Eu^2 ,Dy^3 化学组成的溶胶,然后通过机械研磨、水热反应和微波加热反应三种不同的组装方法和微波还原扩散法使其进入主体ZSM-5沸石的孔道中。主客体材料的荧光光谱出现显著蓝移,余辉光谱出现400nm和517nm两个发射峰,两个余辉峰的相对发射强度随组装方法和组装浓度的改变而具有可调性,呈现有规律的变化。分析其原因是由于发光材料进入沸石的纳米级孔洞引起的。  相似文献
8.
对EDTA配位滴定法测定锌汞合金中汞含量中EDTA的加入量与溶液酸度进行了研究,并对该法进行条件优化。改进后克服了原方法的缺点,适用于汞含量在1%~25%的锌汞合金中汞含量的测定。  相似文献
9.
在铝氟联合中毒的系列研究中 ,发现性发育成熟前头发和血尿高铝的骨软化畸形病人 ,肝、肾铝显著升高的大鼠和鸡的骨铝、脑铝含量在接近或明显甚至显著低于正常对照组时 ,出现了铝骨病和铝危害的其它表现 ;AlCl3 ·6H2 O对童鸡非蓄积危害阈值范围指数 >5 (2 1 40 41 9) ,较低浓度比较高浓度饲铝组病变更为显著 ,铝在一定浓度或剂量范围与反应强度可呈非正相关关系 ;一定浓度以上 ,摄铝与高氟促成铝吸收和蓄积的数倍到 1 0数倍浓度差别的病情差异并不明显。表明人和动物在地壳高铝环境中的长期进化与适应 ,于生长发育旺盛的性成熟前形成并完善了对自然条件下进入内环境高铝的排斥和主动调节保护及自身平衡稳定反应的机制 ,以避免铝危害和减轻铝的危害程度  相似文献
10.
The human red blood cell (RBC) metabolism is investigated by calculating steady state fluxes using constraint-based stoichiometric modeling approaches. For the normal RBC metabolism, flux balance analysis (FBA) is performed via optimization of various alternative objective functions, and the maximization of production of ATP and NADPH is found to be the primary objective of the RBC metabolism. FBA and two novel approaches, minimization of metabolic adjustment (MOMA) and regulatory on-off minimization (ROOM), which can describe the behavior of the metabolic networks in case of enzymopathies, are applied to observe the relative changes in the flux distribution of the deficient network. The deficiencies in several enzymes in RBC metabolism are investigated and the flux distributions are compared with the non-deficient FBA distribution to elucidate the metabolic changes in response to enzymopathies. It is found that the metabolism is mostly affected by the glucose-6-phosphate dehydrogenase (G6PDH) and phosphoglycerate kinase (PGK) enzymopathies, whereas the effects of the deficiency in DPGM on the metabolism are negligible. These stoichiometric modeling results are found to be in accordance with the experimental findings in the literature related to metabolic behavior of the human red blood cells, showing that human RBC metabolism can be modeled stoichiometrically.  相似文献
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