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991.
取代苯系列衍生物电子结构与毒性关系的量子化学研究苏忠民,徐贤姬,李金昶(东北师范大学化学系,长春,130024)赵宝忠,盛连喜(东北师范大学环科系,长春,130024)关键词:取代苯衍生物,分子毒性,MNDO采用量子化学半经验AMI、MNDO方法,从...  相似文献   
992.
993.
IntroductionMethaneandcarbondioxidearetWomaincompositionsforthegreenhouseeffectandtheworldglobewanningll].ItisbeneficialtoourlivingenviroIUnenttocontrolthereleaseofthesetwogases.Theconversionofmethanetothecommonfeedstocksynthesisgas(carbonmonoxideandhydro…  相似文献   
994.
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   
995.
钪—镧—对氟偶氮氯膦体系共显色效应的研究及应用   总被引:3,自引:0,他引:3  
曹建明  罗庆尧 《分析化学》1993,21(11):1306-1309
本文研究了钪-镧-对氟偶氮氯膦体系共显色效应的光度特性及测定钪的最佳条件,建立了光度法测定痕量钪的新方法。该法的表观摩尔吸光系数为8.57×10^4L·mol^-1·cm^-1,Sc(Ⅲ)浓度在0.0-5.0μg/25ml范围符合比尔定律。将本法用于镁基,铁基合成试样中痕量钪的测定,结果满意。  相似文献   
996.
Chemistry is a central science. However, the public's recognition of chemistry needs to be promoted, and the prejudice needs to be reduced. Chemical science popularization is a long-term, complex and arduous social education project, which is of great significance to promote social harmony and improve people's quality of life. This paper summarizes the current status of chemical science popularization in China, and puts forward the innovative development countermeasures which focus on improving public participation, training popular science talents, carrying out popular science popularization education at different levels, creating high-quality science popularization works and opening up new positions and approaches of chemical science popularization. This paper has the reference value for the science popularization colleagues.  相似文献   
997.
耐尔蓝-铌钼杂多酸-聚乙烯醇-124体系测定铌   总被引:2,自引:2,他引:2  
李祖碧  徐其亨 《分析化学》1992,20(5):520-523
在聚乙烯醇-124存在下,耐尔蓝与铌钼杂多酸形成离子缔合物的适宜条件为:在0.025~0.10mol/L硫酸溶液中形成铌钼杂多酸;在1.1~1.8mol/L硫酸溶液中耐尔蓝与铌钼杂多酸形成离子缔合物。缔合物的组成比为NB:NbMo=3:1,λ_(maX)在615nm处,摩尔吸光系数ε为2.46×10~6L.mol~(-1).cm~(-1),符合比耳定律范围0~1.2μg Nb/25ml,至少稳定5h。考察了43种共存离子的影响,绝大多数元素不干扰测定。方法选择性好,灵敏度高,已用于合金钢和岩矿中铌的测定,结果满意。  相似文献   
998.
The influence of additives such as sodium salicylate and sodium chloride on the water solubilization capacity of AOT in n-pentanol solutions has been investigated. The water solubilization capacity is enhanced by sodium salicylate and decreased by sodium chloride. The percolation behavior of the water/AOT/n-pentanol system is studied by modifying the water concentration and temperature. No percolation threshold induced by water or temperature is detected either in the absence or in the presence of additives. The values of ln sigma have a linear correlation with temperature in the range of 5-40 degrees C. The activation energy is also estimated and discussed.  相似文献   
999.
A highly sensitive fluorimetric method for the determination of fluoride was established. The method was based on quenching of the fluorescence of the Al3+-calcein complex in CCl3COOH-CH3COOK buffer solution by fluoride. The fluorescence emission was measured at lambdaex/lambdaem 480/503 nm, and the experimental variables and interference in this determination were studied. The linear calibration range was 0.8 ng/mL to 150 ng/mL and the detection limit was 0.2 ng/mL. The method was applied to determine fluoride in biological materials. The recovery was in the range of 96.3% to 104.7% and the relative standard deviation was 4.6%. The results obtained from the certified reference material by the present method agreed with the certified values.  相似文献   
1000.
Li Q  Chen X  Zhang H  Xue C  Liu S  Hu Z 《The Analyst》2000,125(8):1483-1486
A new Rayleigh light scattering (RLS) assay of protein is presented in this paper. At the optimum pH 4.10, the weak RLS of Arsenazo-DBN can be greatly enhanced by the addition of proteins due to the interaction between protein and Arsenazo-DBN. Based on this, the reactions of Arsenazo-DBN and proteins, including bovine serum albumin, human serum album, gamma-globulin, egg albumin, lysozyme and trypsin, were studied. A new quantitative determination method for proteins has been developed. The linear range for human serum albumin, for example, is 0.085-34.62 micrograms mL-1 with a detection limit of 44.8 ng mL-1. Besides high sensitivity, the method is characterized by good reproducibility, rapidity of reaction, good stability, and few interfering substances. The determination of the proteins in human serum and urine samples by this method give results very close to those obtained using Coomassie Brilliant Blue G-250 colorimetry, with relative standard deviations of 0.7-2.5%.  相似文献   
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