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941.
942.
943.
Hai‐Yan Fu Hai‐Long Wu Yong‐Jie Yu Li‐Li Yu Shu‐Rong Zhang Jin‐Fang Nie Shu‐Fang Li Ru‐Qin Yu 《Journal of Chemometrics》2011,25(8):408-429
A novel third‐order calibration algorithm, alternating weighted residue constraint quadrilinear decomposition (AWRCQLD) based on pseudo‐fully stretched matrix forms of quadrilinear model, was developed for the quantitative analysis of four‐way data arrays. The AWRCQLD algorithm is based on the new scheme that introduces four unique constraint parts to improve the quality of four‐way PARAFAC algorithm. The tested results demonstrated that the AWRCQLD algorithm has the advantage of faster convergence rate and being insensitive to the excess component number adopted in the model compared with four‐way PARAFAC. Moreover, simulated data and real experimental data were analyzed to explore the third‐order advantage over the second‐order counterpart. The results showed that third‐order calibration methods possess third‐order advantages which allow more inherent information to be obtained from four‐way data, so it can improve the resolving and quantitative capability in contrast with second‐order calibration especially in high collinear systems. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
944.
<正>A novel polyamide containing xanthene structure and trifluoromethylphenoxy pendent was prepared from 9,9-bis[4-(4- aminophenoxy)phenyl]xanthene,a novel diamine with 2-(4-trifluoromethylphenoxy)terephthaloyl chloride,by the low temperature polycondensation.This new polyamide with the inherent viscosity of 0.95 dL/g was amorphous and readily soluble in polar solvents such as DMAc,m-cresol,etc.This polyamide showed the glass transition temperature(T_g) of 236℃,decomposition temperature (Td) at 5%weight loss of 455℃and char yield of 56%at 800℃in N_2.Transparent,flexible,and tough film of the polymer cast from DMAc solution exhibited tensile strength of 93 MPa,elongation at break of 14%,initial moduli of 2.2 GPa.The electric properties such as the dielectric constant of 3.03(1 MHz) and surface resistance(2.78×10~(14)Ω),and the moisture uptake of 1.36% were also described. 相似文献
945.
<正>A high-performance capillary electrophoresis with amperometric detection(CE-AD) method has been developed for the analysis of seven bioactive ingredients,namely ferulic acid(FA),vanillin,vanillic acid,p-hydroxybenzoic acid,caffeic acid,gallic acid and protocatechuic acid,in Rhizoma Chuanxiong.The effects of several factors such as the acidity and concentration of running buffer,the separation voltage,the applied potential to working electrode and the injection time were investigated.Under the optimum conditions,the seven analytes could be well separated within 21 min at the separation voltage of 16 kV in a 60 mmol/L borax running buffer(pH 8.7).A 300μm diameter carbon disk electrode has a good response at potential of +950 mV(vs.SCE) for all analytes.Good linear relationship was established over three orders of magnitude with detection limits(S/N = 3) ranged from 3.3×10~(-7) to 6.7×10~(-9)g/mL.This proposed method has been successfully applied for the determination and comparison of different batches of Rhizoma Chuanxiong samples based on their characteristic electrochemical profiles. 相似文献
946.
<正>The chemokine CXCR4 receptor is over-expressed in a wide variety of tumors.In this study,AMD3100,which was a prototype non-peptide antagonist of CXCR4 receptor,was labeled with ~(99m)Tc.~(99m)Tc-AMD3100 was verified by thin layer radio chromatography(TLRC).The tumor-localizing properties of ~(99m)Tc-AMD3100 were evaluated and proved in mice bearing Hep-G2 tumor xenograft.~(99m)Tc-AMD3100 was a promising,novel receptor-specific radiopharmaceutical with potential application in the imaging of human tumors. 相似文献
947.
Alkoxy substituted MeO-BIPHEP-type diphosphines ligands for asymmetric hydrogenation of aryl ketones
<正>In this paper,a series of optically active MeO-BIPHEP-type ligands,(S)-6,6′-dimethoxy-2,2'-bis(di-p-alkoxyphenylphosphine)- 1,1′-biphenyl were synthesized and used to prepare the ruthenium complex.The effects of para-substituted were observed,the results showed that the ruthenium catalysts[diphosphine RuCl_2 diamine]containing both t-Bu and i-Pr substitutions have better activities and enantioselectivities than the non-substituted ruthenium catalysts in the asymmetric hydrogenation of acetophenone. 相似文献
948.
Liang Chun Wu Long Qing Liu Hai Shan Jin Ming Liang Ma Xiao Li Zhao Ke Wen 《中国化学快报》2010,21(10):1263-1266
<正>Two pyrazine-contairting macrocyclic polyazomethines 2 and 3 were synthesized by direct[2 + 2]and[3 + 3]condensation reactions between 2,2'-[pyrazine-2,3-diylbis(oxy)]dibenzaldehyde(1) and hydrazine.Both 2 and 3 were characterized by NMR, HRMS,and their structures were determined via X-ray crystal diffraction studies. 相似文献
949.
增强化学发光酶免疫法对猪肉中盐酸克伦特罗的检测 总被引:4,自引:0,他引:4
建立了猪肉中克伦特罗(CLB)的直接竞争化学发光酶免疫检测(dc-CLEIA)方法。通过优化离子强度、pH值确立了化学发光酶免疫法的标准曲线,优化后dc-CLEIA的检出限可达0.02μg/L。猪肉中的盐酸克伦特罗用高氯酸提取、SPE净化后绘制基质曲线,基质曲线与标准曲线吻合,说明基质影响基本消除。测定0.10、1.0、5.0μg/kg 3个水平的添加回收率,平均回收率为83%~98%,批内与批间的相对标准偏差均小于15%。进一步研究了dc-CLEIA与HPLC两种方法测定猪肉样品的相关性,结果显示两者测定结果相关性良好,r=0.964 7,说明所建立的直接化学发光酶免疫方法可用于实际样品的检测,结果准确可靠。 相似文献
950.
提出了一种鉴别重叠色谱峰类型的化学计量学方法——模差渐进投影(MDEP)法。该方法利用二维色谱数据中相邻两个色谱流出点的光谱矢量模的和与该两个矢量和的模之差,建立模差-时间(dm-t)曲线判断非纯色谱峰的纯组分区,同时判定第二组分色谱流出点和倒数第二组分色谱结束点。分别以纯组分区的光谱矢量建立正交阵对该色谱峰进行投影运算,得到投影后转换色谱。该转换色谱消除了纯组分区所对应化合物的色谱和光谱信息。对转换色谱重复上述操作至整个色谱峰的模差-时间曲线均为0时终止,得到重叠色谱峰各组分的色谱流出点和结束点。利用上述结果,采用不包含待测组分光谱信息的该重叠峰二维色谱数据建立正交矩阵对该色谱峰进行投影运算,获得待测组分的相似色谱图。通过比对分析即可得到该组分在重叠色谱峰中的光谱和色谱信息。依次操作,即可获得重叠色谱峰中各组分的光谱和色谱信息。采用模差渐近投影法对4组分模拟重叠二维色谱峰及杜香挥发油GC-MS的重叠色谱峰进行了解析,方法简便、结果准确。 相似文献