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91.
A simple and accurate RP-HPLC method using photodiode array detection (PAD) was developed for the simultaneous determination of four flavonoids, namely quercetin (QU),luteolin(LU),apigenin(AP) and isorhamnetin (IS) in pigeonpea leaves.Extract samples were separated on HIQ SIL C18V column using methanol-acetonitrile-water(31:10:59, v/v/v) as mobile phase.The flavonoids were detected at 254.5 nm for QU and IS, and at 345 nm for LU and AP.Contents were determined with satisfactory repeatability (R. S. D. < 2.2%) and recovery (97.27 – 99.98%). The developed method was found to be simple and efficient. 相似文献
92.
Effect of multi-walled carbon nanotubes on non-isothermal crystallization kinetics of polyamide 6 总被引:2,自引:0,他引:2
The non-isothermal crystallization behaviors of multi-walled carbon nanotubes (MWNTs)/polyamide 6 (PA6) composites were investigated by differential scanning calorimetry (DSC). Three methods, namely, Avrami, Ozawa and Mo, were carried out to analyze the non-isothermal crystallization data. The results showed that the MWNTs in PA6 acted as effective nucleation agents. However the crystallization rate of composites obtained was lower than that of the neat PA6. It is indicated that the presence of MWNTs influenced the mechanism of nucleation and the growth of PA6 crystallites. 相似文献
93.
94.
Ze-yong Zhao Wei-wei yao Rong-ni Du Qin Zhang Qiang Fu
Ze-hao Qiu Su-lan Yuan
《高分子科学》1996,(1):137-143
Ze-hao Qiu Su-lan Yuan
《高分子科学》1996,(1):137-143
A series of polydimethylsiloxane (PDMS) with varied molecular weights (Mw = 3 61620; 106, 1 61620; 106 and 0.5 61620; 106) were melt blended with PP to investigate the effect of PDMS molecular weight (MW) on the morphology and mechanical properties of PP/PDMS blends. Scanning electron microscopic (SEM) examination showed that the size of PDMS domains was dependent on the MW of PDMS. It was found that the lower the value of PDMS MW, the better dispersion of the PDMS domains in the PP matrix. Tensile and Izod impact tests revealed that the addition of PDMS with lower MW would lead to a more significant increase in impact strength of the blends compared with the blends with higher MW ones, while the influence of the molecular weight on tensile strengths of the blends was relatively small in the MW range studied. Differential scanning calorimetry (DSC) results also showed that the crystallization temperature of PP was increased with decreasing PDMS MW, indicating a better nucleation capability of lower MW of PDMS. Melting flow rate (MFR) measurements indicated that the processibility of PP could be enhanced by adding PDMS, and again the lower MW PDMS resulted in better data. Our work demonstrates that not only the processibility but also the mechanical properties of PP could be enhanced to a more significant degree by using low MW PDMS than the higher ones. 相似文献
95.
Molecular and nanoscale materials and devices in electronics 总被引:2,自引:0,他引:2
Over the past several years, there have been many significant advances toward the realization of electronic computers integrated on the molecular scale and a much greater understanding of the types of materials that will be useful in molecular devices and their properties. It was demonstrated that individual molecules could serve as incomprehensibly tiny switch and wire one million times smaller than those on conventional silicon microchip. This has resulted very recently in the assembly and demonstration of tiny computer logic circuits built from such molecular scale devices. The purpose of this review is to provide a general introduction to molecular and nanoscale materials and devices in electronics. 相似文献
96.
97.
New anti-HIV prodrugs, conjugates of AZT and d4T with boranophosphates, were prepared by the H-phosphonate method. Their structures were determined by negative ion electrospray ionization mass spectrometry (ESI-MS) in conjunction with tandem mass spectrometry (MS/MS). The fragmentation pathways were investigated, and most of the fragment ions contained the boranophosphate or phosphinate group. 相似文献
98.
顺磁性聚酯金属配合物的合成及其驰豫性能的研究 总被引:2,自引:0,他引:2
本文通过二乙三胺五乙酸(DTPA)或乙二胺四乙酸(EDTA)的双酸酐与二元醇或二元酚进行聚合反应,制备了两个系列共15种新的聚酯型大分子配体及其顺磁性金属配合物,用核磁、红外光谱以及元素分析表征了配体和配合物的结构。初步试验结果表明,与相应的小分子金属配合物相比,聚酯金属配合物具有较高的弛豫性能。 相似文献
99.
研究了Cu(Ⅱ)-胱氨酸络合物极谱波的性质;提出了一种用示波极谱法测定蛋白质中胱氨酸的新方法,可在8.0×10~(-4)mol/L Cu~(2+)+8.0×10~(-3)mol/L三乙醇胺的溶液中测定0.05~20mg/L的胱氨酸。 相似文献
100.
Kai Yang Xuan Zhang Enqin Fu Jingui Qin Minoru Kinoshita 《Journal of solid state chemistry》2004,177(11):4300-4304
Two new intercalation compounds were prepared by the reactions of Ni(II) cyclopolyamine complex cations with a preintercalate Mn1−xPS3K2x(H2O)y, respectively, through “ion exchange” process. Their structures were characterized by elemental analysis, X-ray powder diffraction and infrared spectroscopy. The lattice spacing increased 0.567 and 1.093 nm with respect to the pristine MnPS3. Ferrimagnetism of the intercalates was confirmed by SQUID experiment with Tc at 40 and 33 K, respectively. 相似文献