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921.
丙酰胺氯化稀土配合物及其氯化钕配合物催化丁二烯聚合的活性 总被引:2,自引:0,他引:2
合成了组成为LnCl3·3PA的丙酰胺氯化稀土配合物(Ln=Pr,Nd,Eu,Dy;PA=C2H5CONH2).IR表明,丙酰胺是通过酰胺基团的O与Nd进行配位.NdCl3·3PA配合物与烷基铝组成的二元体系,无论是三异丁基铝,二异丁基氢铝或者是三乙基铝都对丁二烯聚合具有较高的催化活性,而且所得聚丁二烯的顺式-1,4结构含量都在98%以上. 相似文献
922.
Jiang X Zhang Z Bai H Qu X Jiang J Wang E Dong S 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2005,61(5):943-951
Electrochemical redox processes of bovine heart cytochrome c were investigated by in situ UV-vis and CD spectroelectrochemistry at bare glassy carbon electrode (GCE) and single-wall carbon nanotubes (SWNTs) modified glassy carbon electrode (SWNTs/GCE) using a long optical path thin layer cell. The spectra obtained at GCE and SWNTs/GCE reflect electrode surface microstructure-dependent changes in protein conformation during redox transition. Potential-dependent conformational distribution curves of cytochrome c obtained by analysis of in situ circular dichroism (CD) spectra using singular value decomposition least square (SVDLS) method show that SWNTs can retain conformation of cytochrome c. Some parameters of the electrochemical reduction process, i.e. the product of electron transfer coefficient and number of electrons (alpha n = 0.3), apparent formal potential (E0' = 0.04 V), were obtained by double logarithmic analysis and standard heterogeneous electron transfer rate constant k0 was obtained by electrochemistry and double logarithmic analysis, respectively. 相似文献
923.
Kang Shi Jing Tang Li Zhang Yong-liang Zhou Dong-sheng Qu Li-Ning Sun Zhong-Qun Tian 《Journal of Solid State Electrochemistry》2005,9(5):398-402
Chemical micro-machining of complex 3-dimensional (3-D) patterns of silicon substrates was preliminarily explored by the confined etchant layer technique (CELT). Through systematic investigation, we demonstrated that cysteine as a scavenger and Br2 as an etchant can be used to etch silicon substrates. The CELT has the potential to develop into a new means of micro-machining complex 3-D patterns on silicon substrates. However, due to the highly corrosive property of the chemicals used for the silicon etched system, great effort must be made to overcome these problems including the mold electrode with high chemical stability.Dedicated to Professor Gygy Horyi on the occasion of his 70th birthday 相似文献
924.
DNA silver staining is widely used to detect DNA fragment in polyacrylamide gel with high sensitivity. Conventional procedures of the silver staining involve several steps, which take about 40 min to 2 h in total. To improve the efficiency of DNA silver staining, a more efficient protocol is developed in this study. The procedure comprises only four steps including impregnating, rinsing, developing, and stopping, and could be completed within 20 min. Nitric acid and ethanol in the silver-impregnation step of the new procedure eliminates the need for prior treatment of gels with a fixing solution and following rinse prior to impregnation with silver. The procedure has high sensitivity and long storage lifetime. The minimum detectable mass of DNA is 0.44 and 3.5 ng in denaturing and nondenaturing polyacrylamide gel, respectively. 相似文献
925.
926.
927.
An analytical method is presented based on reverse isotope dilution single detector inductively coupled plasma magnetic sector mass spectrometry (ID-ICP-SMS) and applied to the specific case of the certification of a (111)Cd enriched candidate Cd spike calibration material (nominal mass fraction 10 mg kg(-1) in 5% HNO3 solution). Uncertainty propagation was used as a tool for both determining the analytical approach and validating it. The robustness of close to "exact matching" reverse IDMS to correction of measured isotope intensities for multiplicative (mass discrimination) and (semi)additive effects (dead time, instrumental background, and isobaric interference) is discussed. The very low experimental relative standard deviation of the mean (0.08%) of eight replicate determinations indicated that all significant sources of uncertainty had probably been taken into account for the estimation of the final combined uncertainty statement (U(c) = 0.17%, k = 1). IRMM-621 was used as comparator. Uncertainties on IUPAC isotopic abundances of 111Cd and 112Cd, for the natural Cd solution involved between the two enriched materials, formed nearly 60% of U(c). The repeatability of the isotope ratio measurements contributed less than 10%. Correction for procedural blank necessitated somewhat unusual calculations (potential contamination of an enriched material with natural Cd). The procedure also involved a quadrupole based ICP-MS judged to be appropriate for the characterization of the isotopic composition. For comparison purposes, direct IDMS results are simulated using identical experimental input data. Finally, a significant background signal in the 106-116 mass region, observed only with the magnetic sector instrument, was attributed to argon based isobaric interferences. 相似文献
928.
痕量铼的同位素稀释中子活化分析 总被引:6,自引:2,他引:6
将同位素稀释法的准确性与中子活性分析(NAA)的高灵敏度相结合,建立了一种新的痕量铼的测试方法,实验中对Re的检出限为0.004ng,全流程空白为0.05ng,地于Re含量为64ng/g的样品,在取样量为50mg时,单次测定误差(2σ)为3.1%,测定Re一为30ng/g的样品,本方法的2σ在3%以内,4次分析的RSD为4.1%,而采用一般的NAA,结果偏低约20%,并且RSD大于5%。 相似文献
929.
离子聚合物在Nylon-1010/PP共混物中的增容作用曲桂杰,刘景江(中国科学院长春应用化学研究所长春130022)关键词聚丙烯,Nylon-1010,离子聚合物,增容选择离子聚合物作为高聚物共混的增容剂,通过离子间的相互作用可达到增容效果[1]。... 相似文献
930.
天然高分子吸附剂研究:Ⅰ.乙二醇双缩水甘油醚交联壳聚糖的制备及其对Cu(? 总被引:15,自引:1,他引:15
报道了乙二醇双缩水甘油醚改性壳聚糖的制备及其对Cu(Ⅱ)、Ni(Ⅱ)的吸附性能,同时考察了PH值、时间、温度等因素对吸附的影响。结果表明,改造后的壳聚糖具有不流失,易再生,在Cu(Ⅱ)、Ni(Ⅱ)共存时能选择吸附Cu(Ⅱ)的特点。 相似文献