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931.
Zhi Qiang LIU Qi FANG* Wen Tao YU Gang XUE Du Xia CAO Dong WANG Guang Ming XIA Min Hua JIANG State Key Laboratory of Crystal Materials Shandong University Jinan 《中国化学快报》2002,13(10)
In common fluorescence process, molecular excitation is caused by the absorption of at least a single photon with shorter wavelength. When certain laser is used as the pump source, some compounds can be excited by simultaneous absorption of at least two photons and then the emission of up-converted fluorescence may occur. This process is called two-photon excited fluorescence (TPEF)1,2. Because of several advantages of TPEF, including intrinsic high three-dimensional resolution and the p… 相似文献
932.
933.
研究了环磷酰的示波极谱法。环磷酰胺经亚硝化反应后,其产物在0.1mol/L HCl介质中于-0.490V附近出现一清晰的阴极还原波。在1.0×1-^-4mol/L范围内,浓度与波高有良好的线性关系,检测下限可达5×10^-8mol/L.用于针剂,注剂和尿液中环磷酰胺的测定均获满意的结果。 相似文献
934.
Mechanism of TiO2-assisted photocatalytic degradation of dyes under visible irradiation: photoelectrocatalytic study by TiO2-film electrodes 总被引:3,自引:0,他引:3
Photoelectrocatalytic degradation of various dyes under visible light irradiation with a TiO(2) nanoparticles electrode has been investigated to reveal the mechanism for TiO(2)-assisted photocatalytic degradation of dyes. The degradation of both cationic and anionic dyes at different biases, including the change in the degradation rate of the dyes and the photocurrent change with the bias potential, the degraded intermediates, the voltage-induced adsorption of dyes, the accumulation of electrons in the TiO(2) electrode, the effect of various additives such as benzoquinone (BQ) and N,N-dimethyl aniline (DMA), and the formation of active oxygen species such as O(2)(*-) and H(2)O(2) were examined by UV-visible spectroscopy, HPLC, TOC, and spin-trap ESR spectrometry. It was found that the dyes could controllably interact with the TiO(2) surface by external bias changes and charging of dyes. The cationic dyes such as RhB and MG underwent efficient mineralization at negative bias, but the N-dealkylation process predominated at positive bias under visible light irradiation. The discolorations of the anionic dyes SRB and AR could not be accelerated significantly at either negative or positive bias. At a negative bias of -0.6 V vs SCE, O(2)(*-) and dye(*+) were formed simultaneously at the electrode/electrolyte interface during degradation of cationic RhB. In the case of anionic dyes, however, it is impossible for the O(2)(*-) and dye cationic radical to coexist at the electrode/electrolyte surface. Experimental results imply both the superoxide anionic radical and the dye cationic radical are essential to the mineralization of the dyes under visible light-induced photocatalytic conditions. 相似文献
935.
利用电荷迁移反应测定头孢羟氨苄 总被引:4,自引:0,他引:4
提出一种基于电荷迁移反应简便可靠地测定头孢羟氨苄的分光光度法。在甲醇-乙醇介质中,头孢羟氨苄与氯冉酸于50℃反应15min能够形成稳定的1:1络合物,其λmax=528nm,线性范围为20 ̄400mg/L。用拟定的方法测定原粉和胶囊,结果与药典法一致。对浓度100mg/L的药物10次测定相对标准偏差为1.4%,样品的标准加入回收率为99.0% ̄100.8%。 相似文献
936.
本文以三氟化硼乙醚作催化剂,在一缩二乙二醇存在下,进行了1,1,5-三氢八氟戊基缩水甘油醚与四氢呋喃的共聚合反应,用气相色谱、薄层色谱、红外光谱和核磁共振等方法研究了从共聚物中分离出来的物质,发现含有带乙氧基的小分子化合物,它是由催化剂带入到聚合体系中的轻微量乙醚的作用而产生的,同时还会产生带乙氧基的单羟基共聚物,以三氟化硼四氢呋喃代替三氟化硼乙醚进行了同样的共聚合反应,所得的共聚物中单羟基共聚物较少。 相似文献
937.
Suyao?Xiao Xuanming?LiuEmail author Chunyi?Tong Jun?Liu Dongying?Tang Lijian?Zhao 《中国科学B辑(英文版)》2005,48(2):162-166
Anion starch nanoparticle (StNP) with a diameter of 50 nm was prepared in water-in-oil microemulsion, with soluble starch
as raw materials and POCl3 as crosslinking agent. PLL-StNP was prepared by linking poly-L-lysine (PLL) on the surface of StNP. At the same time, the
size of PLL-StNP and its stability in aqueous solution were checked by AFM. The analysis of plasmid DNA binding, DNase I enzymatic
degradation, toxicity and transfection were done. We discovered that PLL-StNP may be used as non-virus nanoparticle gene carrier.
And we developed the method of preparing PLL-StNP gene carrier and used it in cell transfection. As non-virus gene carrier,
PLL-StNP has some advantages, such as large load of DNA, high transfection efficiency, low cell toxicity and biodegradability. 相似文献
938.
Shouzhi Pu Jingkun Xu Liang Shen Qiang Xiao Tianshe Yang Gang Liu 《Tetrahedron letters》2005,46(5):871-875
The photochromic diarylethene, 1,2-bis(2-methyl-5-(2-(1,3-dithiolpentane))-thien-3-yl)perfluorocyclopentene (BMDTP), has been synthesized in high yield and its structure was determined by X-ray crystallographic analysis. The compound undergoes a photochromic reaction both in solution and in the single crystalline phase. In addition, its fluorescence property in solution is discussed. 相似文献
939.
在极谱催化波和吸附波方面,国内进行了大量的研究,但汞的络合物吸附波至今未见报道。钯试剂已用于光度法测定钯等。我们在研究该试剂与金属离子络合的极谱行为时发现,在硼砂介质中,试剂与Hg~(2+)可形成电活性络合物并可用于汞的测定。 相似文献
940.