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排序方式: 共有68条查询结果,搜索用时 390 毫秒
1.
Yongtao Bai Lihua Song Yongheng Zhang Guoliang Dai Weidong Zhang Shanshan Song Hong Sun Wen Jing Meijuan Xu Wenzheng Ju 《Biomedical chromatography : BMC》2019,33(9)
A highly selective and efficient LC–MS/MS method was developed to determine the plasma concentration of magnolol, hesperidin, neohesperidin and geniposide following oral administration of Zhi‐Zi‐Hou‐Po decoction in normal and depressed rats. Plasma samples were pretreated by protein precipitation with methanol. Chromatographic separation was performed on an XTerra® MS C18 column using a gradient elution with a mobile phase composed of acetonitrile–0.1% aqueous formic acid. The proposed method was validated to be specific, accurate and precise for the analytes determination in plasma samples. The calibration curves displayed good linearity over definite concentration ranges for the analytes. The intra‐ and inter‐day precision of the proposed method at three different levels were all within <11.13% and the relative errors ranged from ?8.46 to 8.93%. The recovery of the four compounds ranged from 82.72 to 89.08% and no apparent matrix effect was observed during sample analysis. After full validation, the established method was successfully applied for comparing the pharmacokinetics of four components between normal and depressed rats. The results showed that the AUC and Cmax of four analytes in depressed rats were significantly different from those in normal rats and might provide helpful information to guide the clinical use of Zhi‐Zi‐Hou‐Po to treat depression. 相似文献
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The morphology of different ratio K/V catalysts supported on porous α‐alumina substrate was investigated by atomic force microscopy (AFM). Changes in the particle size distribution, pore size distribution were analyzed respectively using AFM software. In addition, their catalytic activities and compositions for carbon oxidation were studied by x‐ray diffraction (XRD), differential scanning calorimetry (DSC), and temperature‐programmed reactions (TPR). As a result, with the increase of K concentration, the mean particle size gradually increased and the mean pore size decreased. According to the catalytic activity studies, the catalytic activity of the KVO3 and K3V5O14 phases are more effective than KCl. 相似文献
4.
Microchimica Acta - Carbon nanofibers were synthesized by chemical vapor deposition using alkali chloride catalysts at a temperature range from 500 to 700 °C. Depending on the... 相似文献
5.
SnO2 nanowires with an average 0.6 μm in length and about 25 nm in diameter were prepared by a hydrothermal method. The sensors were fabricated using SnO2 nanowires assembled with Pd nanocrystals. The sensing properties of the sensors such as selectivity, response-recovery time and stability were tested at 290 °C. After assembling Pd nanocrystals onto the surface of SnO2 nanowires, the gas sensing properties of the sensors toward H2S were improved. The sensors based on Pd nanoparticle@SnO2 nanowires exhibit high stability owing to stable single crystal structure. The mechanism of promoting sensing properties with Pd nanoparticles is discussed. 相似文献
6.
二乙烯基苯泡沫空心球微流体成型技术 总被引:1,自引:1,他引:0
基于微流体成型技术,设计开发了一套用于微胶囊制备的T型微通道乳粒发生器,并利用该装置实现了二乙烯基苯空心泡沫微球的连续制备。以二乙烯基苯的邻苯二甲酸二丁酯溶液为油相,以聚乙烯醇的水溶液为外水相,去离子水为内水相,成功制备出二乙烯基苯双重微乳液,并采用水平旋转加热装置使其凝胶固化,再经过溶剂交换、CO2超临界干燥等过程,制备出直径700~1200μm、壁厚60~100μm、密度90~120mg.cm-3的二乙烯基苯空心泡沫微球。利用光学显微镜、扫描电镜和X-透射显微镜表征,结果显示:微胶囊球形度、同心度和壁厚均匀性较好,成活率较高,直径单分散性较好,外表面较粗糙。 相似文献
7.
对12C6+ 离子辐照诱变高产阿维链霉菌株ZJAV-Y1-203 和原始菌株ZJAV-A-1 的摇瓶发酵pH 值、菌体浓度、碳源和氮源代谢进行了测定,研究了12C6+ 辐照对阿维链霉菌的代谢效应。在发酵前期(48h),原始菌株发酵液pH 值低于突变菌株;在发酵96~196 h,诱变高产菌株ZJAV-Y1-203 繁殖快,生长旺盛,N的利用率高;菌体浓度大于原始菌株的浓度,且发酵液的pH 稳定,菌体处于代谢相对更稳定期;在发酵144~240 h,诱变高产菌株ZJAV-Y1-203 对糖源消耗低于原始菌株ZJAV-A-1。这些结果表明,12C6+ 离子辐照对阿维链霉菌代谢影响有利于阿维菌素合成。pH value, mycelium concentration, carbon source and nitrogen metabolism in flask fermentation of the mutant high-producing strain ZJAV-Y1-203 and the original strain ZJAV-A1 have been investigated, in order to show the metabolic effect of avermitilis irradiated by ion beam of 12C6. In early stage (48 h) of the fermentation, pH value of the original fermentation was lower than that of the mutant strains. In 96~196 h of fermentation, the nitrogen utilization in the strains ZJAV-Y1-203 was higher than that in the original strains, its reproductive was fast, and its growing was vigorous. The mycelium concentration of ZJAV-Y1-203 was greater than the original strain, and the pH value of fermentation were stable, so its metabolism was relatively more stable. In 144240 h of fermentation, the strain ZJAV-Y1-203 on sugar consumption was less than the original strains. The effect of 12C6 ion irradiation on metabolism of Streptomyces avermitilis is conducive to the synthesis of avermectin. 相似文献
8.
Chengbin Jing Jinxia Hou Xinguang Xu Yongheng Zhang 《Applied Physics A: Materials Science & Processing》2008,90(2):367-373
A new idea of using LPD (liquid phase deposition) to prepare a GeO2 thick reflective film for hollow waveguide delivery of CO2 laser radiation was investigated in this work. The LPD process was achieved by designedly adding acid to GeO2–aqueous ammonia. The addition of acid could induce the transformation of germanate ions into GeO2 solutes, leading to the deposition of a GeO2 ceramic film when the concentration of GeO2 solute is higher than its saturation solubility. It was found that the highest film growth rate occurred at a pH value of
3, while a film with low surface roughness and good adhesion to the substrate was produced at a pH value of 2 and the film
could be converted to a smooth, compact hexagonal GeO2 film by heat treatment at 1120 °C for 30 min. Two abnormal dispersion bands within 7.6–9 μm and 9.6–11.2 μm were mainly caused
by the silica glass substrate and the GeO2 film, respectively. The film was thick enough to achieve the total reflectance of the CO2 laser radiation. The use of this GeO2 film in a hollow waveguide structure for CO2 laser radiation delivery is discussed based on the transmission loss and the feasibility of the deposition of the GeO2 film inside silica capillary tubes. The results show that the hollow waveguides with low transmission loss are most likely
fabricated at a low cost using the LPD-derived GeO2 reflective film.
PACS 78.20.-e; 78.66.-w; 42.70.-a; 78.20.Ci; 78.40.-q 相似文献
9.
Dr. Yutao Liu Hui Chen Tong Li Yongheng Ren Hui Wang Zhengxuan Song Jianhui Li Prof. Qiang Zhao Prof. Jinping Li Prof. Libo Li 《Angewandte Chemie (International ed. in English)》2023,62(37):e202309095
Polycrystalline metal–organic framework (MOF) layers hold great promise as molecular sieve membranes for efficient gas separation. Nevertheless, the high crystallinity tends to cause inter-crystalline defects/cracks in the nearby crystals, which makes crystalline porous materials face a great challenge in the fabrication of defect-free membranes. Herein, for the first time, we demonstrate the balance between crystallinity and film formation of MOF membrane through a facile in situ modulation strategy. Monocarboxylic acid was introduced as a modulator to regulate the crystallinity via competitive complexation and thus concomitantly control the film-forming state during membrane growth. Through adjusting the ratio of modulator acid/linker acid, an appropriate balance between this structural “trade-off” was achieved. The resulting MOF membrane with moderate crystallinity and coherent morphology exhibits molecular sieving for H2/CO2 separation with selectivity up to 82.5. 相似文献
10.
光催化具有无污染、安全高效等优点,已成为环保领域的研究热点。 本文选择2,4-二(3,5-二甲基吡唑)-6-二乙基胺-1,3,5-三嗪(L1)和2, 6-二[3-(5-甲基吡唑基)]吡啶(L2)为配体、以RuCl3为金属源,合成了3种配合物[Ru(L1)Cl3](1)、[Ru(L2)2]·Cl3(2)和[Ru(L2)2]·(H2BTC)·(HBTC)·H2O(3),同时进行了IR、UV-Vis、TG及X射线衍射等表征,并对配合物在光催化降解罗丹明B方面进行了探讨,结果表明,配合物13均具有一定程度的光降解效果,降解效果分别为46.8%、44.7%和40.4%。 相同条件下,加入H2O2后的配合物13的降解效果比金属盐、配体及H2O2单独存在时的降解效果好。 相似文献