5,10,15,20-四(对-磺酸苯基)卟啉四钠盐水溶液的稀释热和活度系数的研究

使用LKB 2107微热量计系统和等压法测量仪,分别测量了25℃时5,10,15,20-四(对-磺酸苯基)卟啉四钠盐水溶液的稀释热和活度系数,计算了相对偏摩焓。     

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

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．     

Effect of electrode surface microstructure on electron transfer induced conformation changes in cytochrome c monitored by in situ UV and CD spectroelectrochemistry

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.     

A preliminary study on chemical micro-machining of complex three-dimensional patterns on silicon substrates

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     

Efficient and sensitive method of DNA silver staining in polyacrylamide gels

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.     

混合型杂多化合物M_x[GaW_9M_3O_(40)]·nH_2O的合成和性质

本文报道了M_x[GaW_9M_3~′O_(40)]nH_2O(M′=Mo,V,Ti,Fe(Ⅲ),Co(Ⅱ),Ni(Ⅱ),Mn(Ⅱ);M=k,Na,Gua,Me_4N,Et_4N,Bu_4N)的合成。通过元素分析,阴离子电荷的确定,极谱、IR及UV光谱、可见光谱、ESR、磁化率测定对其进行了表征。并研究了它们在水溶液中对酸碱的稳定性及热稳定性。     

生物热动力学研究——大肠杆菌生长速率和激活能

大肠杆菌生长的全热谱已被测定,再进一步根据其指数生长期的热谱信息,确定了它的生长速率和激活能。在指数生长期,细菌数按指数规律增加,可用下式表示:n_t=n_0e~(kt)(1)式中:t为指数生长期开始后的某一时间,n_0,n_t分别为指数生长期开始时和t时的细菌数,k为生长速率常数。因此,同期细菌输出的热功率也是按指数规律同步增长。可表示为:     

Low uncertainty reverse isotope dilution ICP-MS applied to certifying an isotopically enriched Cd candidate reference material: A case study

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.     

痕量铼的同位素稀释中子活化分析

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％。     

离子聚合物在Nylon－1010／PP共混物中的增容作用

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］。...