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101.
A Novel Dihydroflavone from the Roots of Uvaria Macrophylla 总被引:1,自引:0,他引:1
A new dihydroflavone (1), named macrophyllol A, was isolated from the roots of Uvaria macrophylla. Its structure was elucidated on the basis of spectroscopic evidence. 相似文献
102.
GuoXiangCHENG GuangLingPEI LingGangZENG LiYongZHANG ChaoLIU 《中国化学快报》2004,15(2):242-245
In this paper, the surface imprinted cross-linked polystyrene beads were prepared via suspension polymerization with styrene (St), divinylbezene (DVB), polyvinyl alcohol (PVA1788),the mixture of Span 85 and xylene or the mixture of Span 85 and paraffin as monomer,cross-linking agent, dispersion stabilizer and templates, respectively. The results indicate that there are dense cavities on the surface of beads, and the diameter and density of cavity are related with the composition and amount of emulsion template. The forming mechanism of cavity from thermodynamics and dynamics was proposed. 相似文献
103.
The ESR signals of bilirubin-IXα were studied including the samples treated with free radical generating and inhibiting systems, i.e.X-X0., Fe/EDTA, SOD, mannitol/ascorbate, DTPA, KCN et al.These stable signals all comprise those originated from a semiquinone radical(g=2.0012)and superoxide radical(g11=2.041, g⊥=2.0040).The latter is shown to be bound with metal ionsespecially iron, chelated by bilirubin.The iron probably comes from bilirubin precursor---hemootobin.Active oxygen free radical scavengers may destroy these radicals.Kinetic curves of regeneration of the bilirubin radicals have been determined.Bilirubin is discussed as"active oxygen trap"in mammatians. 相似文献
104.
本文报导的方法是在南京大学高鸿教授研究的K_3Fe(CN)_6示波极谱滴定法(在PH8的K_2HPO_4—KH_2PO_4—KBr底液中,用0.04660mol/LK_3Fe(CN)_6标准溶液对纯抗坏血酸测定)的基础上,考虑到L—抗坏血酸(以下简称V_e)在碱性、中性介质中稳定性差,如用于V_e含量很微的果蔬测定,对结果影响大。本文改为H_2C_2O_4—KBr的酸性介质作底液,用 相似文献
105.
Wei Luo Xiang Kai Fu Li Hua Ma 《中国化学快报》2007,18(7):883-886
The high quality TiO2, MoO3-doped WO3 electrochromic film was prepared by the sol–gel method for the first time. The sol, which has hydrogen peroxide (H2O2) and oxalic acid (H2C2O4), was very stable at room temperature and quite suitable for the deposition of films. The WO3 electrochromic film prepared from this doped sol had excellent performance, such as short response time, no cracks, good adhesion to the substrate, high coloring efficiency and longevity of service. 相似文献
106.
Simplistic modeling approach to heterogeneous dilute-acid hydrolysis of cellulose microcrystallites 总被引:9,自引:0,他引:9
Pär O. Pettersson Robert W. Torget Robert Eklund Qian Xiang Y. Y. Lee Guido Zacchi 《Applied biochemistry and biotechnology》2003,106(1-3):451-455
The classic kinetic model for cellulose hydrolysis is often referred to as pseudo-homogeneous, a term revealing the insight that the process is actually heterogeneous. During the past 10–15 yr, the shortcomings of this
model have been demonstrated in various studies and the interest in the heterogeneous aspects has increased. The present work
presents a simplistic model in which the intrinsic, heterogeneous hydrolysis and transport rates are coupled by the assumption
of a constant glucosidic surface concentration. The mechanisms affecting these two rates are largely unknown, but the model
serves as a guideline for further exploration of the process. 相似文献
107.
A Novel Dimeric Coumarin from Clausena lenis 总被引:1,自引:0,他引:1
HongPingHE ShunTingCHEN YueMaoSHEN ChangXiangCHEN YiBinZHAO XiaoJiangHAO 《中国化学快报》2003,14(11):1150-1153
A novel dimeric coumarin (1), a dimeric of seselin named diseselin A, was isolated from the aerial part of Clausena lenis. The structure was elucidated based on the MS, 1D and 2D NMR data. 相似文献
108.
Dispersion of copper(Ⅱ) phthalocyanine (CuPc), copper(Ⅱ) phthalocyaninesulfonate (CuPcS) and cobalt(Ⅱ)phthalocyaninetetrasulfonate (CoPcTS) on the surface of titanium dioxide was investigated by XRD, XPS, FT-IR and UV-Vis techniques. Results show that interaction between CuPc and TiO2 was very weak and CuPc was difficult to disperse on the surface of the support. While partly sulfurized CuPcS could be dispersed on the surface of support through sulfo-groups and its dispersion capacity was determined to be 0.085 g CuPcS/g TiO2. Completely sulfurlzed CoPcTS could also be dispersed on the surface of TiO2 as a monolayer and its dispersion capacity was 0.12 g CoPcTS/g TiO2. Interactions of the sulfo-groups as well as the electrons of CoPcTS with the surface of TiO2 could be evidenced by FT-IR characterization. Therefore, it was suggested that CoPcTS molecules be adsorbed on the surface of TiO2 in a flat-lying mode while CuPcS in a slanting one. UV-Vis spectra show that the dispersed CuPcS and CoPcTS molecules exist in both forms of monomers and dimers. 相似文献
109.
本实验测定了二苄基马来酸酯甲醇溶液的荧光光谱,并发现马来酸酐对该荧光体系有猝灭作用,通过对不同马来酸酐浓度与各种浓度的二苄基马来酸酯甲醇溶液在400nm处荧光强度数据的分析,发现马来酸酐的浓度与荧光猝灭程度在一定范围内呈良好的线型关系。据此,提出了用荧光猝灭法对马来酸酐及二苄基马来酸酯的定量分析 相似文献
110.
由2-氰-5-氟-3H-4-嘧啶酮和取代苯酚钠在常压下反应,合成了7个未见文献报道的2-芳氧基-5-氟-3H-4-嘧啶酮化合物,产率70 ̄87%,结构经IR、^1H NMR和MS证实。 相似文献