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941.
α-酮酸酯的合成研究进展   总被引:1,自引:0,他引:1  
α-酮酸及其酯是一类双官能团化合物, 性质活泼而特殊, 是重要的有机合成、药物合成及生物合成中间体。文中扼要论述了近二十年来α-酮酸酯的合成研究进展。  相似文献   
942.
BaLaB_9O_(16)中Ce~(3+)敏化Dy~(3+)发光的机理   总被引:1,自引:0,他引:1  
在紫外光激发下,研究了BaLaB9O(16)中Dy(3+)、Ce(3+)的发光光谱、激发光谱、发光强度及荧光寿命随着组成变化的规律性.结果表明:De(3+)对Dy(3+)的发光有相当强的敏化作用,Ce(3+)→Dy(3+)的能量传递效率可高达93%,能量传递的机理为电偶极-偶极相互作用的共振传递.根据349nm激发下Dy(3+)发光强度与浓度的关系,证明了Dy(3+)发光的自身浓度猝灭机理也为电偶极-偶极相互作用.  相似文献   
943.
944.
A magnetic filter — continuous electrodeionization (CEDI) hybrid separation system was investigated for the purification of the primary coolant in a nuclear power plant. A magnetic filter system with a 3000 Gauss magnetic field and a CEDI system with a cell consisting of 3 compartments were used for the removal of magnetite and nickel ions, respectively. The hybrid separation system achieved removal rates of 98% for magnetite and 99% for the nickel ions demonstrating its feasibility for the purification of primary coolant.The authors gratefully acknowledge the Basic Atomic Energy Research Institute (BAERI) program at the Korea Institute of Science and Technology Evaluation and Planning (KISTEP) for the financial support to carry out this work.  相似文献   
945.
In this paper, zinc tetraaminophthalocyanine (Zn-APc) was immobilized on cellulosic fiber by covalent bond to obtain a novel cellulosic fiber supported metallophthalocyanine, named Zn-TDTAPc-F. At pH 11, upon visible light irradiation for 6 h in the presence of O2, Zn-TDTAPc-F was found to be highly effective for the degradation of phenol in aqueous solution, and the degradation rate of phenol was more than 95%. HPLC was used to confirm formic acid, fumaric acid and maleic acid as its main degradation products.  相似文献   
946.
In aqueous solution, the micellization and microenvironment characteristics of the micelle assemblies of three anionic surfactants, sodium 1-(n-alkyl)naphthalene-4-sulfonates (SANS), have been investigated by steady-state fluorescence and time-resolved fluorescence decay techniques using pyrene, Ru(bpy)3(2+), and 1,6-diphenyl-1,3,5-hexatriene as fluorescence probes. The critical micelle concentrations (cmc's), effective carbon atom numbers (neff's), hydrophilic-lipophilic balances (HLBs), mean micelle aggregation numbers, micropolarities, and microviscosities of these surfactant micelles have been determined. The logarithmic cmc of the alkylnaphthalene sulfonates decreases linearly with an increase in the neff. The logarithmic aggregation number of the alkylnaphthalene sulfonates increases linearly with an increase in the neff. However, in contrast to the alkylsufonates and the alkylbenzene sulfonates, the aggregation for these alkylnaphthalene sulfonate molecules is less sensitive to the increase in the neff. The micropolarity of these alkylnaphthalene sulfonate micelles is less sensitive to the increase in the alkyl chain length and is lower than that of sodium dodecyl sulfate (SDS). The microviscosity of these alkylnaphthalene sulfonate micelles increases with an increase in the alkyl chain length and is lower than those of nonionic surfactants and zwitterionic surfactants. These results suggest that naphthyl rings have a notable effect on the micellization of SANS.  相似文献   
947.
A series of novel 2,4-diaminopyrimidine-modified compounds was designed and synthesized. Compound 14 showed micromolar dual inhibitory effect on both FP-2 and PfDHFR, and potential inhibition to the proliferation of P. falciparum 3D7 strain and chloroquine-resistant P. falciparum Dd2 strain.  相似文献   
948.
研究了Li+,Mg2+/SO42-,B4O72-—H2O四元交互体系25℃时的溶解度和溶液的密度及折光率.四种原始组份未发生脱水作用,体系中也没有复盐或固溶体形成.体系25℃溶解度等温线由五段组成,有四个结晶区,分别对应于四种原始组份,其中以MgB4O7·9H2O的结晶区最大.溶解度等温线上有两个零变量点,其一为MgB4O7·9H2O,MgSO4·7H2O,Li2SO4·H2O三盐共饱点,另一为MgB4O7·9H2O,Li2B4O7·3H2O,Li2SO4·H2O三盐不相称共饱点.  相似文献   
949.
The chemiluminescence (CL) of peracetic acid (PAA) in alkaline medium is very weak but is strongly enhanced after the addition of dihydralazine sulfate (DHZS). Based on this phenomenon, a simple, rapid and highly sensitive flow-injection CL method for the determination of DHZS was developed. The CL emission was linearly related to the DHZS concentration in the range of 20–4000 ng mL−1 with a detection limit (3σ) of 1.2 ng mL−1. As a preliminary application, the proposed method was successfully applied to the determination of DHZS in pharmaceutical preparations; the recovery of DHZS in human urine was between 96.5% and 102.2%. A detailed CL mechanism was proposed and singlet molecular oxygen (1O2) was suggested to be produced in the CL reaction process.  相似文献   
950.
Four mixed-valent ruthenium diphosphonates, namely, Na(4)[Ru(2)(hedp)(2)X]x16H(2)O [X = Cl (1), Br (2)], K(3)[Ru(2)(hedp)(2)(H(2)O)(2)]x6H(2)O (3), and Na(7)[Ru(2)(hedp)(2)Fe(CN)(6)]x24H(2)O (4), where hedp represents 1-hydroxyethylidenediphosphonate [CH(3)C(OH)(PO(3))(2)](4-), were synthesized and structurally characterized. Compounds 1, 2, and 4 show linear chain structures in which the mixed-valent [Ru(2)(hedp)(2)](3-) dimers are linked by X(-) or [Fe(CN)(6)](4-) bridges. Compound 3 contains discrete species of [Ru(2)(hedp)(2)(H(2)O)(2)](3-) where the axial positions of [Ru(2)(hedp)(2)](3-) paddlewheel are terminated by water molecules. Magnetic studies show that significant antiferromagnetic exchanges are mediated between the [Ru(2)(hedp)(2)](3-) (S = 3/2) units through halide bridges in compounds 1 and 2.  相似文献   
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