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81.
Wei Ge ZHANG Ying Hua JIN Ping QI Kai BAO Jin Guang LIN Nai Li WANG Xin Shen YAO 《中国化学快报》2006,17(1):9-11
Erythromycin has been extensively used in the treatment of bacterial infections for over 50 years1. In addition to the antimicrobial effect, the quite unique antiinflammatory activity of the erythromycin derivatives has attracted much attention as new the… 相似文献
82.
Uniform and sphere-like nanoparticles of crystalline Pr3+-doped CaTiO3 have been prepared from complex polymer precursor at 600°C, in which, metal atoms are previously dispersed by citric acid in ethylene glycol solvent. The decomposition process of the precursor, crystallization, and particle sizes of CaTiO3 have been investigated by using thermal analysis, powder X-ray diffraction and transmission electron microscopy. Diffuse reflectance spectra, photoluminescence and decay curve indicate that a strong red emission located at the nearly NTCS “ideal red” site is deduced from the energy transfer from the band gap absorption to doping Pr3+ ions. The thermoluminescence curves exhibit that a potential long phosphorescent material based on Pr3+-doped CaTiO3 will be explored in future. 相似文献
83.
Guo Jin-xin Sun Si-xiu Zhu Rong-xiu Yin Zhi-lei Yu Hai-yun Li Da-zhi Zhang Wei-min Xu Xian-gang Sun Xuan Shao Hua 《Journal of Radioanalytical and Nuclear Chemistry》2004,261(1):221-224
The 222Rn emanation fraction (EF) released from the technically enhanced naturally occurring radioactive material (TE-NORM) wastes
at certain sites of petroleum and gas production was determined. The samples were analyzed by γ-ray spectrometry to determine
the activity concentration of the 226Ra content, of which the 222Rn emanation fraction was calculated. The results showed that the 222Rn emanation fraction differs in the oil and gas production sites and it is independent of the activity concentration of 226Ra.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
84.
A new approach to indolizines has been developed using a 5-endo-trig iodocyclization of allylic esters followed by isomerization and dehydroiodination facilitated by triethylamine at rt. This mild procedure enabled us to synthesize a number of highly substituted indolizines in good yields. 相似文献
85.
M. Friedrich K. Hiller M. Wiemer T. Geßner D. R. T. Zahn 《Analytical and bioanalytical chemistry》1998,361(6-7):558-559
Basic investigations have been carried out on the characterization of different processing steps in bond preparation using
etched <111> faces of silicon wafers for the incidence of the infrared beam to a multiple internal reflection geometry. The
method is very sensitive to the surface coverage and interface. Surface activation by RCA cleaning yields an increase of water
coverage and a decrease of SiH and CH groups. The detection limit for an oxide layer between silicon wafers has been found
to be about 3 nm.
Received: 18 July 1997 / Revised: 15 August 1997 / Accepted: 19 August 1997 相似文献
86.
JPC – Journal of Planar Chromatography – Modern TLC - In this work we have studied the separation of a mixture of the sulfonylurea herbicides (metsulfuron-methyl, chlorsulfuron,... 相似文献
87.
The alkylation of ethylenethiourea with alcohols and aqueous acids (HCl, HBr, and HI) allows the synthesis of the respective S-alkyl-isothioureas in high yield and purity. Consistently high yields (91-98%) were obtained with 56% HI, the yields for 48% HBr (48-93%) and 37% HCl (36-85%) were lower and varied with the type of alcohol. The method is a convenient low-cost alternative to the use of alkyl iodides and an easy access to the S-tert-butyl isothiourea. 相似文献
88.
89.
反相高效液相色谱法测定3种中成药中的葛根素 总被引:7,自引:0,他引:7
建立了测定小儿清感灵片、步长新脑心通胶囊和感冒清热颗粒 3种中成药中葛根素含量的反相高效液相色谱方法。采用APEXODS色谱柱 ,以醋酸铵缓冲液 (10 0mmol/L ,pH 5 0 ) 甲醇 (体积比为 75∶2 5 )的混合溶液为流动相 ,检测波长为 2 5 0nm ,流速为 0 8mL/min。葛根素在 2mg/L~ 2 0mg/L时其色谱峰面积与质量浓度的线性关系良好 (r =0 9999) ;上述 3种中成药中的葛根素含量分别为 3 48mg/g ,1 0 8mg/ g及 1 5 2mg/ g(蔗糖型 ) ;其加样回收率分别为 99 0 % ,93 4%和 97 5 %。该法简便、快速、专属性强 ,可以作为多种中药制剂中葛根素含量的测定方法。 相似文献
90.
Yanli Zeng Lingpeng Meng Shijun Zheng Maofa Ge Dianxun Wang 《Chemical physics letters》2004,400(4-6):394-400
A cluster DFT (B3LYP) calculation study of ClN3 and BrN3 dissociation pathways catalyzed by molecular sieve is reported. A three-tetrahedral molecular sieve cluster (Al(OHSiH3)(OSiH3)(OH)2, called T3) has been chosen in this study. Triplet-state products ClN and BrN are more easily produced with T3 molecular sieve cluster. Although the potential energy surfaces with T3 molecular sieve cluster are similar with those without T3 molecular sieve cluster, the dissociation process of ClN3 and BrN3 with T3 molecular sieve cluster becomes easier, which can be attributed to smaller energy gaps from the ground state reactant to the intersystem crossing point. 相似文献