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41.
中药炮制是中药学的特色和优势,也是最具我国自主知识产权的学科之一.中药炮制研究的核心是阐明中药炮制机理,这也是制约中药现代化的关键节点.目前大部分中药的炮制机理尚不明确,有待进行系统深入的研究.咖啡豆需要烘培后才可以制成饮料,这个高温烘培过程类似于中药的炮制过程.近年来,国内外专家对咖啡豆高温烘培过程化学成分变化及其机理进行了深入研究,各种新方法和新技术得到广泛应用,取得了系列研究成果,这些研究成果为中药炮制机理研究提供了多种新思路和新方法,也为中药炮制机理的研究和阐明提供了重要示范. 相似文献
42.
Fu-Qiang Jin Jian-Chun Zhang Min Li Xin-Min Hao Hua Zhang 《Journal of Dispersion Science and Technology》2013,34(8):1148-1151
NaOH/poly(sodium acrylate) composites were prepared by in situ polymerization of acrylic acid with an overneutralization level by adding excess NaOH. The composites were studied by XRD, IR and 23Na MAS NMR spectroscopy. The results showed that the high neutralization degree (>100%) may lead to a complete polymerization. Both XRD and 23Na MAS NMR spectra did not show any peaks of phase-separated NaOH or Na2CO3 until the neutralization degree was up to 217.5%. It can be presumed that the aggregates of Na+ ions can contain approximately two Na+ units for every carboxyl group before the phase separation. 相似文献
43.
Genxiang Luo Chunsheng Liu Qingdao Wang Wang Hao Ping 《Journal of Dispersion Science and Technology》2013,34(4):543-546
A simple formula for calculating the degree of counterion binding of dressed micelles is presented. This approximate expression for the spherical micelle is derived from the extending Langmuir's method in the case of high surface potentials. It works quite well for the estimation of the degree of counterion binding of micelles. The simple form is very convenient for practical use. 相似文献
44.
Chiral N-[1-benzyl-2-hydroxyethyl]-3-[2-oxo-pyrrole]propionamide (C16H22N2O3) was obtained unexpectedly from the reaction of oxazoline involving pyrrolidone with copper acetate monohydrate, and the structure was characterized by NMR, IR, elemental analysis, and X-ray analysis. 相似文献
45.
Preparation and characterization of ZrCO/C composite aerogels 总被引:1,自引:0,他引:1
Li Ye Wenfeng Qiu Hao Li Aijun Zhao Tao Cai Tong Zhao 《Journal of Sol-Gel Science and Technology》2013,65(2):150-159
Zr-containing organic aerogels were synthesized by ligand substitution reaction of polyzirconoxone and 2, 4-dihydroxybenzoic acid, followed by polymerization with formaldehyde, and then supercritical drying using CO2. After carbonization and carbothermal reduction under an argon atmosphere, ZrCO/C composite aerogels with controllable zirconium content (47.8–78.6 wt%) were obtained. The carbothermal reduction was substantially completed at 1,500 °C, and the obtained ZrCO/C composite aerogels exhibit low oxygen contents (9.4–6.7 wt%) and high surface areas (589–147 m2/g). Pore morphologies of the ZrCO/C composite aerogels were investigated in detail by nitrogen sorption measurements, scanning electron microscopy and its associated energy-dispersive X-ray microanalysis measurements. The results show that the aerogels are composed of carbon framework and Zr-conglomerations, and the surface area of aerogel is severely affected by its zirconium content. The presence of reductive ZrC crystals can greatly enhance the oxidation resistance ability of amorphous carbon framework and prevent collapse. 相似文献
46.
Microscopic structures of Zn(II) adsorbed on anatase TiO2 surface with different densities were studied using extended X-ray absorption fine structure (EXAFS) spectroscopy and density functional theory (DFT) calculation. Quantitative analysis of the EXAFS spectra showed that microscopic structures of Zn(II) were fourfold coordinated complexes, and different microscopic structures were present of the solid surface. Three modes of corner–corner/sharing-corner/sharing-edge adsorptions on anatase (101) face cluster were calculated by the DFT method. The results from DFT method were consistent with the EXAFS fittings. The optimized Zn–O average distance of the Zn–O tetrahedron was determined as about 2.00 Å. The Zn–Ti distance was 3.69 Å for the corner–corner adsorption, 3.35 Å for the sharing-corner adsorption, and 3.02 Å for the sharing-edge adsorption. According to the adsorption energies calculated by the DFT method, the microscopic structure of corner–corner adsorption was less stable than those of the other adsorption modes. With the increasing adsorption density, the corner–corner adsorption mode would be enhanced more intensively than the other adsorption modes. 相似文献
47.
Wei Wang Xue-Mei ZhaoJing-Li Wang Xin GengJun-Fang Gong Xin-Qi Hao Mao-Ping Song 《Tetrahedron letters》2014
Primary aromatic amides can be synthesized from aldehydes and hydroxylamine hydrochloride in the presence of Cs2CO3. Various aromatic aldehydes (include some heteroaromatic aldehydes) are able to generate the corresponding aromatic amides in moderate to excellent yields. 相似文献
48.
Qingpei Xiang Dongfeng Tian Fanhua Hao Chengsheng Chu Ge Ding Jun Zeng Fei Luo 《Journal of Radioanalytical and Nuclear Chemistry》2014,299(3):1439-1445
In recent years, the cerium-doped lanthanum bromide, LaBr3 (Ce = 5 %) detector is increasingly playing an important role in radiation measurements because of its higher energy resolution (~3 % at 662 keV), faster luminescence decay time (~35 ns) and higher detection efficiency compared to 7.65 cm × 7.65 cm NaI(Tl) detector. Intrinsic spectra between 1,800 and 3,000 keV derived from internal radioactivity within LaBr3(Ce) scintillators have been investigated in some literatures, and these results are confirmed by the experiments in this work. In this paper, a new method for LaBr3(Ce) detector energy calibration from 100 to 2,000 keV is proposed using the intrinsic spectra (self-calibration) instead of the standard gamma sources. Proof-of-concept experiment results show that self-calibration can guarantee energy accuracy of better than 0.815 % and can be applied outside the laboratory. The stability and applicability of this method are also investigated systematically. 相似文献
49.
Hao Zhang Hui Huang Zihan Lin Xingguang Su 《Analytical and bioanalytical chemistry》2014,406(27):6925-6932
Graphene is a two-dimensional carbon nanomaterial one atom thick. Interactions between graphene oxide (GO) and ssDNA containing different numbers of bases have been proved to be remarkably different. In this paper we propose a novel approach for turn-on fluorescence sensing determination of glucose. Hydrogen peroxide (H2O2) is produced by glucose oxidase-catalysed oxidation of glucose. In the presence of ferrous iron (Fe2+) the hydroxyl radical (?OH) is generated from H2O2 by the Fenton reaction. This attacks FAM-labelled long ssDNA causing irreversible cleavage, as a result of the oxidative effect of ?OH, producing an FAM-linked DNA fragment. Because of the weak interaction between GO and short FAM-linked DNA fragments, restoration of DNA fluorescence can be achieved by addition of glucose. Due to the excellent fluorescence quenching efficiency of GO and the specific catalysis of glucose oxidase, the sensitivity and selectivity of this method for GO-DNA sensing are extremely high. The linear range is from 0.5 to 10 μmol L?1 and the detection limit for glucose is 0.1 μmol L?1. The method has been successfully used for analysis of glucose in human serum. Figure
? 相似文献
50.
Jia-chang Zhuang Yi-Hua Zhang Ning Song Yu-hui Tan Yun-zhi Tang Yan-Le Huang Hao Zhang Yu-kong Li 《化学:亚洲杂志》2022,17(1):e202101134
Cyclic organic amines are emerging as excellent building blocks to assemble organic–inorganic hybrid phase transition materials due to their flexible cyclic structure. Here, we have assembled a 1D organic-inorganic hybrid dielectric material C5H6NOPbBr3 ( 1 ) by alloying the cyclic organic amine 3-hydroxypyridine. 1 displays a remarkable switchable dielectric response induced by an order-disorder transformation of the organic moiety, this transformation behaviour is confirmed by DSC and Hirshfeld surface measurements. More interestingly, 1 has a narrowband emission (FWHM=4.64 nm) at 590 nm; FWHM is a major quality figure for narrowband photodetectors. In addition, 1 exhibits semiconducting properties with an indirect bandgap of 2.78 eV by the analysis of the UV-Vis absorption results. 相似文献