冠醚化合物对乳剂的增感作用

研究了冠醚化合物对AgBr八面体乳剂的增感作用。结果表明:孔穴直径与Ag⁺直径相匹配的1,7,10,16-四氧-4,13-二硫杂环十八烷对AgBr乳剂具有很强的增感作用,然而1,7,10,16-四氧-4,13-二氮杂环十八烷及1,4,7,10,13,16-六氧环十八烷对AgBr乳剂无增感效果。因此冠醚化合物对乳剂的增感作用与其环上所含杂原子的种类有关。由于7,8-苯并-1.5-二硫杂环壬烷(BDT)、13,14-苯并-1,4,8,11-四硫杂环十四烷(TTX)和1,4,8,11-四硫杂环十四烷(TTP)的孔穴直径远小于Ag⁺的直径,当单独加入乳剂时,无增感作用。但是,在乳液中加入TTX或TTP的同时,加入一定量的金盐,随TTX或TTP加入量的增加,成熟时间的延长,其对乳剂的增感作用与常规的硫增感变化趋势相同,增感的同时,灰雾也增大。不论加合与否,BDT对乳剂无增感效果,冠醚化合物对乳剂的增感作用与冠醚孔穴大小也有密切关系,由于冠醚的加入,均使AgBr乳剂的离子电导值降低。     

溴碘化银乳剂互易律效应的研究

本文研究了化学增感剂对溴碘化银乳剂的高照度互易律失效(HIRF)的影响。在金增感,铱[Ir(Ⅳ)]增感和还原增感的溴碘化银乳剂中,没有发现HIRF,但硫增感引起显著的HIRF,金-硫、铱-硫、还原增感剂-硫增感时,大大减少单独由硫增感引起的HIRF。     

铋(Ⅲ)-8-羟基喹哪啶体系的极谱行为——表面活性剂增敏机理和分析应用——Ⅲ.十二烷基苯磺酸钠对铋(Ⅲ)-、铅(Ⅱ)-8-羟基喹哪啶,铜(Ⅱ)-、镉(Ⅱ)-、锌(Ⅱ)-乙二胺体系电流增敏机理对比和规律

研究并比较了十二烷基苯磺酸钠(SDBS)对Bi(Ⅱ)-、Pb(Ⅰ)-8-羟基喹哪啶,Cu(Ⅰ)-、Cd(Ⅰ)-、Zn(Ⅰ)-乙二胺体系示波极谱电流的增敏效果,和对峰电位的影响及有关试验。表明SDBS只对能形成螯合阳离子者起增敏作用,其增敏程度则受SDBS在电极表面与相应螯合阳离子是形式缔合物,还是因超载静电吸引产生诱导吸附作用所制约。前者最佳可增敏达60余倍,后者最佳可增敏10余倍。     

几个8-氨基喹啉新衍生物与钴(Ⅱ)的显色和荧光反应的比较研究

系统研究了所合成的七个8-氨基喹琳-5-偶氮苯类和三个8-(对甲苯磺酸氨基)喹啉-5-偶氮苯类新衍生物与Co(Ⅱ)的显色和荧光反应。发现了试剂取代基对配合物显色增敏和荧光增感的规律,探讨了H_2O_2对荧光增感的机理。     

多胺修饰β-环糊精对两种荧光体系增敏作用的研究

本文研究了β-环糊精（1）、单-[6-乙二胺-6-脱氧]-β-环糊精（2）、单-[6-二乙烯三胺-6-脱氧]-β-环糊精（3）和单-[6-（三乙烯四胺）-6-脱氧]-β-环糊精（4）对Al（Ⅲ）-H2QS荧光体系和Zn（Ⅱ）-Morin荧光体系的增敏作用。实验结果表明：主体环糊精及其衍生物对At（Ⅲ）-H2QS荧光体系增敏率为4〉3〉2〉1,对Zn（Ⅱ）-Morin体系为3〉4〉2〉1,并且所有的主体环糊精对前一体系的增敏作用都强于后者。研究了酸度对环糊精的增敏能力的影响,发现在两个体系中,体系的pH值对β-环糊精的增敏率影响较小,而对多胺修饰环糊精的影响较大。从修饰环糊精的边臂长度、主-客体的尺寸匹配、静电相互作用、疏水作用等方面探讨了多胺修饰环糊精对两种荧光体系增敏作用的贡献。     

多胺修饰β-环糊精对铝-铁试剂荧光体系的增敏作用

研究了β－环糊精（1）、单－[6-乙二胺－6－脱氧]-β－环糊精（2）、单-[6-(二乙烯三胺）-6-脱氧]-β-环糊精（3）和单-[6-(三乙烯四胺）－6－脱氧]-β-环糊精（4）对铝－铁试剂荧光体系的增敏作用。实验结果表明：加入β－环糊精及其衍生物后体系的荧光强度均增强，增敏率为4＞3＞2＞1，其中4给出最大的荧光增敏率。研究了pH值在3.0-7.5之间酸度对主体化合物增敏能力的影响，发现体系的pH值对β－环糊精的增敏率影响较小，而随着体系酸性的增强，多胺修饰β－环糊精的增敏作用显著增强。探讨了修饰环糊精引入边臂的长度和主－客体间的尺寸适合等因素对铝－铁试剂体系荧光增敏率的影响。     

混合增溶剂对离子缔合物作用的研究

慈云祥等在研究铂、钯、金-碘化钾-丁基罗丹明B显色体系时发现,使用明胶或阿拉伯胶与TritonX-100的混合液,有良好的增溶作用和极好的增敏效应。我们的研究表明:在不少离子缔合物显色体系中,聚乙烯醇-TritonX-100或阿拉伯胶-β-环糊精等混合液,也有很好的增溶(或分散)、增敏和增稳作用。     

3-取代-5(3-乙基-4,5-二苯基噻唑叉)洛丹宁的增感性能

简单份菁(或称零甲川份菁)是一种可以用作卤化银感光乳剂层感蓝增感的染料。彩色正性材料的发展,要求感蓝乳剂层使用氯溴化银乳剂,并配合使用感蓝增感染料以符合感蓝区域的光谱要求。以氩离子激光为光源的电子分色片乳剂要求对波长488nm附近有较高的敏感,此种乳剂本身感色范围偏离氩离子激光发射峰。寻找增感效率高、光谱增感峰适合的感蓝染料很有必要。本文用2-甲硫基-3-乙基-4,5二苯基噻唑对甲苯磺酸盐(1)分别与3-取代洛丹宁(2)在无水乙醇存在下反应,制得六个未见文献报导的3-取代-5-(3-乙基-     

β-环糊精与CTAB微乳液协同增敏荧光法测定微量铋研究

β-环糊精与CTAB微乳液协同增敏荧光法测定微量铋研究;铋（Ⅲ）;β-环糊精;微乳液;增敏;荧光分析法     

杜仲叶中绿原酸的协同增敏荧光光谱法测定

研究了四硼酸钠-阳离子表面活性剂十六烷基三甲基溴化铵(CTMAB)微乳液混合体系对绿原酸的协同荧光增敏作用.结果表明,单独存在的四硼酸钠和CTMAB对绿原酸的荧光强度无显著增敏作用,但四硼酸钠-CTMAB混合体系对绿原酸具有较好的协同荧光强度增敏作用.在优化条件下,绿原酸浓度在0.13～1.32μg·mL<-1>范围内...     

杂质及铈作用下铝锂合金的应力集中敏感性

建立了评价铝锂合金应力集中敏感性的缺口敏感因子,通过测定薄板法拉伸性能,求出了不同元素及杂质含量的铝锂合金缺口敏感因子,Fe,Si,Na,K杂质均明显地增加2090及8090合金的应力集中敏感性,铈能够在一定程度上降低具有较高强度水平的合金应力集中敏感性,但在塑性水平较高的1420合金中,铈添加量超过一定限度后,反而会显著提高材料的应力集中敏感性,相对于普通铝合金,铝锂合金的应力集中敏感性一般处于较高水平,这个问题在此对类合金的实际研究中应给予充分注意。     

典型燃料点火延迟时间的一阶和二阶局部和全局敏感度分析

Sensitivity analysis is an important tool in model validation and evaluation that has been employed extensively in the analysis of chemical kinetic models of combustion processes. The input parameters of a chemical kinetic model are always associated with some uncertainties, and the effects of these uncertainties on the predicted combustion properties can be determined through sensitivity analysis. In this work, first- and second-order global and local sensitivity coefficients of ignition delay time with respect to the scaling factor for reaction rate constants in chemical kinetic mechanisms for combustion of H₂, methane, n-butane, and n-heptane are examined. In the sensitivity analysis performed here, the output of the model is taken to be natural logarithm of ignition delay time and the input parameters are the natural logarithms of the factors that scale the reaction rate constants. The output of the model is expressed as a polynomial function of the input parameters, with up to coupling between two input parameters in the present sensitivity analysis. This polynomial function is determined by varying one or two input parameters, and allows the determination of both local and global sensitivity coefficients. The order of the polynomial function in the present work is four, and the factor that scales the reaction rate constant is in the range from 1/e to e, where e is the base of the natural logarithm. A relatively small number of sample runs are required in this approach compared to the global sensitivity analysis based on the highly dimensional model representation method, which utilizes random sampling of input (RS-HDMR). In RS-HDMR, sensitivity coefficients are determined only for the rate constants of a limited number of reactions; the present approach, by contrast, affords sensitivity coefficients for a larger number of reactions. Reactions and reaction pairs with the largest sensitivity coefficients are listed for ignition delay times of four typical fuels. Global sensitivity coefficients are always positive, while local sensitivity coefficients can be either positive or negative. A negative local sensitivity coefficient indicates that the reaction promotes ignition, while a positive local sensitivity coefficient suggests that the reaction actually suppresses ignition. Our results show that important reactions or reaction pairs identified by global sensitivity analysis are usually rather similar to those based on local sensitivity analysis. This finding can probably be attributed to the fact that the values of input parameters are within a rather small range in the sensitivity analysis, and nonlinear effects for such a small range of parameters are negligible. It is possible to determine global sensitivity coefficients by varying the input parameters over a larger range using the present approach. Such analysis shows that correlation effects between an important reaction and a minor reaction can have relatively sizable second-order sensitivity coefficient in some cases. On the other hand, first-order global sensitivity coefficients in the present approach will be affected by coupling between two reactions, and some results of the first-order global sensitivity analysis will be different from those determined by local sensitivity analysis or global sensitivity analysis under conditions where the correlation effects of two reactions are neglected. The present sensitivity analysis approach provides valuable information on important reactions as well as correlated effects of two reactions on the combustion characteristics of a chemical kinetic mechanism. In addition, the analysis can also be employed to aid global sensitivity analysis using RS-HDMR, where global sensitivity coefficients are determined more reliably.     

SnO_2/ZnO及ZnO/SnO_2双层膜的气敏性质

采用动态脉冲法研究了ＳｎＯ２／ＺｎＯ及ＺｎＯ／ＳｎＯ２ 双层膜的气敏性质。结果表明：选择合适的膜厚及膜厚比,可获得灵敏度及选择性良好的气敏元件。讨论了一些影响双层膜气敏性质的因素,结合元素的扩散,初步解释了膜厚与灵敏度的关系。     

An optimal method of DNA silver staining in polyacrylamide gels

DNA silver staining has widely been used to detect DNA fragments in polyacrylamide gels with high sensitivity. We developed an optimal method for DNA silver staining on polyacrylamide gels. The novel procedure can be completed within 10 min instead of over 20 min with the conventional methods. The sensitivity is significantly improved by the silver-ion sensitizer (Eriochrome black T (EBT)) and the minimum of 0.11 and 1.75 ng of DNA amount can be detected in denaturing and nondenaturing polyacrylamide gel, respectively. Compared with the conventional silver staining methods, the improved optimal method can save time and display high sensitivity, color uniformity, and long storage time of the staining gels.     

老年人彩度对比敏感度函数研究及滤波应用

为研究老年人彩色视觉频率响应特性，获取彩度对比敏感度与空间频率之间的函数关系，本文在LCH均匀颜色空间基础上，固定明度和色调角值，以彩度作为变量，设计人眼彩度对比敏感度实验，进行人眼视觉观察实验。获得彩度对比敏感度与空间频率的关系，并构建指数型对比敏感度函数模型。经分析表明老年人眼彩度对比敏感度随着空间频率的增加，产生先升高再缓慢降低的变化，各色调角下彩度对比度存在差异。经分析人眼对比敏感度差异与人眼视觉辨色特性有很大的相关性。并且，将构建的对比敏感度函数模型用于实现基于人眼视觉系统的滤波处理。     

Sensitivity of a planar micro-flame ionization detector

The sensitivity of a MEMS μFID with reduced fuel gas consumption for portable applications like mobile GC or THA is examined. It is shown that sensitivity depends on flame size and type of sample gas supply (either separate supply or premixed with the hydroxygen). In contrast to conventional FIDs, the sensitivity of the μFID increases with decreasing molecule size. The sensitivity to methane can be optimized up to conventional values. Measurements with the μFID as a second detector in a μGC module prove the additional functionality of such a system.     

The use of unsymmetrical indirect covariance NMR methods to obtain the equivalent of HSQC-NOESY data

We have recently demonstrated that unsymmetrical indirect covariance NMR methods can be used to mathematically calculate the equivalent of low sensitivity, hyphenated NMR experiments by combining data from a pair of higher sensitivity experiments. The present report demonstrates the application of this method to the combination of HSQC and NOESY spectra to provide results comparable to HSQC-NOESY data, albeit with greater sensitivity and with considerably less spectrometer time.     

Enhancement of conductometric detection of weak acids in ion chromatography

Anions of weak acids can represent a problem when determined via chemically suppressed ion chromatography as the acids can be weakly ionised, giving low conductivity and hence low sensitivity. Previous work showed that converting some weak acids back to their sodium salts, using a second micromembrane suppressor, greatly enhanced conductivity and thus sensitivity. This paper will discuss further work in optimising the conversion for boric acid by using sodium salts of EDTA and the mechanisms involved.     

离子交换-原子捕集-火焰原子吸收光谱法测定水中的超痕量镍

在文中所述条件下,镍的原子捕集灵敏度较常规法高320倍,即在离子交换法浓缩仅40倍的情况下,可使镍的测定灵敏度提高12800倍,从而成功实现了ppt级超痕量镍的测定。     

Reducing experimental variability in variance-based sensitivity analysis of biochemical reaction systems

Sensitivity analysis is a valuable task for assessing the effects of biological variability on cellular behavior. Available techniques require knowledge of nominal parameter values, which cannot be determined accurately due to experimental uncertainty typical to problems of systems biology. As a consequence, the practical use of existing sensitivity analysis techniques may be seriously hampered by the effects of unpredictable experimental variability. To address this problem, we propose here a probabilistic approach to sensitivity analysis of biochemical reaction systems that explicitly models experimental variability and effectively reduces the impact of this type of uncertainty on the results. The proposed approach employs a recently introduced variance-based method to sensitivity analysis of biochemical reaction systems [Zhang et al., J. Chem. Phys. 134, 094101 (2009)] and leads to a technique that can be effectively used to accommodate appreciable levels of experimental variability. We discuss three numerical techniques for evaluating the sensitivity indices associated with the new method, which include Monte Carlo estimation, derivative approximation, and dimensionality reduction based on orthonormal Hermite approximation. By employing a computational model of the epidermal growth factor receptor signaling pathway, we demonstrate that the proposed technique can greatly reduce the effect of experimental variability on variance-based sensitivity analysis results. We expect that, in cases of appreciable experimental variability, the new method can lead to substantial improvements over existing sensitivity analysis techniques.