5''''-硝基水杨基荧光酮荧光熄灭法测定微量钨

本文基于Ｗ（Ⅵ）－５′－硝基水杨基荧光酮（５′－Ｎ－ＳＡＦ）－Ｔｗｅｅｎ－８０体系的荧光熄灭效应，提出一种测定微量钨的新荧光方法。在０．２～１．０ｍｏｌ／Ｌ的硫酸介质中，在Ｔｗｅｅｎ－８０存在下，５′－Ｎ－ＳＡＦ存在两个激发峰，其激发波分别为λｅｘ１＝４７５ｎｍ，λｅｘ２＝５０５ｎｍ，发射波长为λｅｍ＝５２５ｎｍ。Ｗ（Ⅵ）与５′－Ｎ－ＳＡＦ形成１∶３的配合物。钨浓度在每２５ｍＬ０．２５～２．５μｇ范围内呈线性关系，检测限为每２５ｍＬ０．２５μｇ。本法灵敏度高，选择性好，不经分离可直接测定合金钢中的钨，结果满意。     

流动注射分析中混合釜体积与进样量的关系

在流路系统和载流速一定且进样体积不大于反应器体积的０．４５倍时，系统混合釜总体积Ｖｍ与进样体积Ｓｖ的关系可表示为：Ｖｍ＝（ａ＋ｂＳｖ）／（１＋Ｓｖ），ａ和ｂ为与实验条件有关的常数。单体积为定值，与进样体积无关，在流路系统和进样体积一定时，混合釜总体积为定值，与载流流速无关。     

膜富集分光光度法测定微量锌

以５－Ｂｒ－ＰＡＤＡＰ为显色剂，用ＷＸ型混合纤维素滤膜（孔径０．６５μｍ，φ２５ｍｍ）富集微量锌，用乙醇溶解富集物（Ｚｎ（Ⅱ）－５－Ｂｒ－ＰＡＤＡＰ）分光光度法测定锌，Ｚｎ（Ⅱ）－５－Ｂｒ－ＰＡＤＡＰ在乙醇溶液中最大吸收波长为５５５ｎｍ，表观摩尔吸光系数１．０９×１０＾５Ｌ．ｍｏｌ＾－１．ｃｍ＾－１，锌量在０．１～５．０μｇ／５ｍＬ，范围内符合比耳定律，本法灵敏度高，操作简便，应用于食品，水样中锌     

5′—硝基水杨基荧光酮荧光熄灭法测定微量钨

本文基于Ｗ（Ⅵ）－５′－硝基水杨基荧光酮（５′－Ｎ－ＳＡＦ）－Ｔｗｅｅｎ－８０体系的荧光熄来效应，提出一种测定微量钨的荧光方法，在０．２～１．０ｍｏｌ／Ｌ的硫酸介质中，在Ｔｗｅｅｎ－８０存在下，５′－Ｎ－ＳＡＦ存在两个激发峰，其激发波分别为λｅｘ１＝４７５ｎｍ，λｅｘ２＝５０５ｎｍ发射波长为λｅｍ＝５２５ｎｍ。Ｗ（Ⅵ）与５′－Ｎ－ＳＡＦ形成１：３的配合物，钨浓度在每２５ｍＬ０．２５～２．５μｇ范围     

介质对配合物稳定性的影响 Ⅳ.Cu(SCN)~ -NaNO_3-tert-Butyl Alcohol-H_2O体系,25℃

本文用分光光度法确定了２５℃下配阳离子Ｃｕ（ＳＣＮ）＋在ＮａＮＯ３－叔丁醇－水介质中的稳定常数。混合溶剂中叔丁醇组成为０，５，１０，１５，２０和２５ｗｔ％，离子强度范围为０．２～３．０ｍｏｌｅ·ｄｍ－３，溶液的ｐＨ＝１．５～１．６。基于Ｐｉｔｚｅｒ理论用最小二乘多项式逼近法，确定了混合溶剂中配合物热力学稳定常数。讨论了配位反应的一级介质效应。     

化学镀非晶态镍磷和镍钨磷双层组合镀层工艺研究

本文着重研究非晶态Ｎｉ－Ｐ和Ｎｉ－Ｗ－Ｐ双层组合镀层的化学镀工艺条件：如镀液组分及ＰＨ值等对镀层在分，镀层沉积速率的影响。实验结果表明；在苹果酸体系中化学镀镍磷镀层比较合适的艺条件为；硫酸镍０．１ｍｏｌ／Ｌ，次磷酸钠０．２５ｍｏｌ／Ｌ、苹果酸０．２０ｍｏｌ／Ｌ，琥珀酸０．１５ｍｏｌ／ｌ，ｐＨ＝４．５－５．０温度为９０℃。     

桑色素—溴化十六烷基三甲铵—Brij—35荧光光度法测定微量…

研究了在溴化十六烷基三甲铵（ＣＴＭＡＢ）和Ｂｒｉｊ－３５混合表面活性剂的存在下，以桑色素为荧光剂，测定微量钨的新方法。详细研究了反应条件，反应适宜的酸度为０．０６￣０．１２ｍｏｌ·Ｌ＾－１ ＨＣｌ，钨含量在０．０５￣３．２５μｇ／２５ｍｌ范围内呈线性关系，方法的灵敏度高，用于地质试样中钨测定，结果满意。     

氯化十六烷基二甲基苄基铵PVC膜糖精离子选择电极的研制

本文以氯化十六烷基二甲基苄基铵为活性材料研制成ＰＶＣ碳棒涂膜式糖精电极。其线性响应范围为５．０×１０￣－５～１．０×ｌ０￣－１ｍｏｌ／Ｌ，响应斜率５３．２ｍＶ／ｐｃ。将电极用于饮料中糖精含量测定，回收率在９０％～１１０／范围内。     

微酸性体系电沉积光亮锡钴锌合金的研究

本文提出了一种电沉积光亮锡钴镜三元合金的新工艺，其溶液组成及操作条件为：Ｎａ３Ｃ６Ｈ５Ｏ７．２Ｈ２Ｏ１００－１５０，Ｎａ２ＥＤＴＡ．２Ｈ２Ｏ２０－３０，ＳｎＣｌ２．２Ｈ２Ｏ１５－２０，ＣｏＳＯ４．７Ｈ２Ｏ２５－３５，ＺｎＣｌ２１５－２０ｇ．Ｌ＾－１；稳定剂ＷＤＺ－１ ６０－１００，光亮剂ＷＤＺ－２１５－２０ｍＬ．Ｌ＾－１，ｐＨ＝４－６，Ｄｋ＝０．５５。０Ａ．ｄｍ＾－２，Ｔ＝５－３５℃。在此条件下可     

毛细管气相色谱负压热导检测器及其应用

根据对负压下热导检测器的响应特性与检测器参数的系统研究，研制出适用于程序升温毛细管气相色谱的热导检测器（ＴＣＤ）。它的最小等效池体积为１．３μｌ，线性动态范围４个数量级，响应速度≤０．１ｓ，对丁烷的最小敏感浓度为０．００５％（Ｖ／Ｖ）。内径≥０．２５ｍｍ的各类毛细管柱可直接与检测器连接而不需用尾吹气。所设计的毛细管色谱进样装置，能在程序升温条件下保证流经分析柱的流量恒定、分流比恒定。解决了程序升温     

平面汞膜电极二阶倒导数电位溶出分析法研究

对电位溶出的Ｅ－ｔ曲线进行二阶倒导数处理，提高了二阶倒导数电位溶出分析法理论，其信号较一阶倒导数法增强约４３．１ｎ倍，分辨率由原来的６５．５ｍＶ／ｎ改善到４８．２ｍＶ／ｎ。用根据二阶倒导数法原理自行设计研制的多阶倒导数电位出仪验证了本提出了的理论，富集１２０ｓ，Ｃｄ＾２＋的检测限可达１．０×１０＾－１０ｍｏｌ／Ｌ。     

伯胺萃取醋酸振荡体系的微量热法研究

用注入/滴定微量热计测定了伯胺N1923氯仿液萃取醋酸的萃取振荡反应体系的热功率—时间曲线,得到了萃取振荡反应体系的诱导期,第一振荡周期和第二振荡周期.计算了表观活化参数,建立了诱导期与振荡周期和起始醋酸浓度、温度间的关系式.     

茂金属线性低密度聚乙烯的组成均匀性

茂金属线性低密度聚乙烯的组成均匀性徐旭荣徐君庭封麟先陈伟（浙江大学高分子科学与工程学系杭州３１００２７）（中国石化总公司石油化工科学研究院北京１０００８３）关键词线性低密度聚乙烯，组成均匀性，茂金属催化剂８０年代以来，茂金属催化剂得到迅速发展．...     

Modelling the flow of liquid in continuous dialyzer

The paper deals with the modelling of the flow of liquid in a compartment of continuous dialyzer. Two simple models, the dispersion model and tanks-in-series model, were used. Their parameters Peclet number, the mean residence time of liquid in dialyzer compartment, the number of tanks and the mean residence time of liquid in each tank were determined from a nonideal step input of a tracer and its response. It has been found that in the range of the Reynolds number from 0.44 to 3.64, the Peclet number and the number of tanks are in the range from about 200 to 320 and from 100 to 310, respectively. Both these parameters and the mean residence time of liquid in the compartment of dialyzer and in each tank decrease with the increasing Reynolds number. Furthermore, it has been proved that the values of the mean residence time of liquid in the compartment of dialyzer calculated from the dispersion model agree well with those calculated from the tanks-in-series model. The obtained values of the Peclet number and the number of tanks indicate that the flow in the dialyzer does not significantly differ from the plug flow.     

The performance of a fast testing system for illicit materials detection based on energy-dispersive X-ray diffraction technique

A prototype setup for detecting illicit materials by energy-dispersive X-ray diffraction (EDXRD) has been developed. The obtained results of NaCl by the equipment suggest that the total measurement system is reliable and can be used to detect different kinds of materials. The tests of TNT, methamphetamine and heroin are also performed on this equipment and the related EDXRD spectra are obviously influenced by the detecting angle and the X-ray sources. The detecting angle of 10° is more suitable for detecting TNT and methamphetamine, while 12° is better for heroin. Moreover, the curves of TNT, methamphetamine and heroin emitted by W target have more diffraction peaks than those emitted by Cu or Mo target, while the peak intensities of TNT and methamphetamine emitted by Mo are stronger than those emitted by Cu or W target. The curve of methamphetamine emitted by Mo target shows a special characteristic and exhibits a super strong diffraction peak located at 1.62 Å^{− 1}, which can be attributed to the effect arising from Mo kα and kβ.     

The influence of tungsten on the chemical composition of a temporally evolving nanostructure of a model Ni-Al-Cr superalloy.

The influence of W on the temporal evolution of gamma' precipitation toward equilibrium in a model Ni-Al-Cr alloy is investigated by three-dimensional atom-probe (3DAP) microscopy and transmission electron microscopy (TEM). We report on the alloys Ni-10 Al-8.5 Cr (at.%) and Ni-10 Al-8.5 Cr-2 W (at.%), which were aged isothermally in the gamma + gamma' two-phase field at 1073 K, for times ranging from 0.25 to 264 h. Spheroidal-shaped gamma' precipitates, 5-15 nm diameter, form during quenching from above the solvus temperature in both alloys at a high number density (approximately 1023 m-3). As gamma' precipitates grow with aging at 1073 K, a transition from spheroidal- to cuboidal-shaped precipitates is observed in both alloys. The elemental partitioning and spatially resolved concentration profiles across the gamma' precipitates are obtained as a function of aging time from three-dimensional atom-by-atom reconstructions. Proximity histogram concentration profiles (Hellman et al., 2000) of the quaternary alloy demonstrate that W concentration gradients exist in gamma' precipitates in the as-quenched and 0.25-h aging states, which disappear after 1 h of aging. The diffusion coefficient of W in gamma' is estimated to be 6.2 x 10-20 m2 s-1 at 1073 K. The W addition decreases the coarsening rate constant, and leads to stronger partitioning of Al to gamma' and Cr to gamma.     

FT-IR studies on the conformation and effective head-group area of AOT molecules in W/O microemulsions

Using Fourier transform infrared(FT-IR) spectroscopy technique, the carbonyl stretching vibration bands of AOT in sodium bis(2-ethylhexyl)sulfosuccinate (AOT)/isooctane/water reverse (W/O) microemulsions system have been investigated by least square curve fitting. The results indicate that an asymmetric adsorbed peak of carbonyl stretching vibration of AOT molecule is situated in (1739 ± 1) and (1725 ± 2) cm-1. The two peaks correspond to different carbonyls in gauche conformation and trans conformation of AOT molecules, respectively. With different water contents (W0), the variations of peak intensity ratio (/= l1739/l1725) reflect the change of the ratio for the two conformation populations and the variations of the effective head-group area of AOT molecule have relations to the ratio of two conformation populations.     

Interpolation of parameters of solutions expressed as functions of composition

The number of parameters in the polynomial is discussed for N components and a polynomial extending up to power n. This number is found to be but may be N less for relative thermodynamic functions. The equation of degree n for an N-component system requires the use of data for each of the i-component systems. Data on the n-component systems suffice if n相似文献   

微量热法研究鹿茸4个活性部位对肠道特征菌群生长代谢的影响

建立灵敏表征鹿茸中具有补益活性的4个部位对两种肠道特征菌群生长代谢影响的评价方法.采用微量热法,在不同给药条件作用下,以产热功率-时间曲线(热谱曲线)的特征参数(生长速率常数(k)、最大产热功率(Pmax)、达峰时间(tp)及有效率(E)等)为指标,对肠道主要有益菌(青春双歧杆菌)生长代谢程度进行客观地量化评价.挑选鹿茸促菌最强的活性部位,进一步考察该部位对病原微生物(金黄色葡萄球菌)生长抑制的作用规律.结果表明,鹿茸不同活性部位促进青春双歧杆菌生长代谢强弱顺序为:正丁醇乙醚氯仿乙酸乙酯.活性最强的正丁醇萃取液对病原微生物(金黄色葡萄球菌)抑制影响的研究表明,正丁醇萃取液在浓度大于200μg·mL-1时,对金葡菌生长具有抑制作用.且tp随药液浓度的增加而相应地延长;k,Pmax均随浓度的增加而相应地减小.微量热法具有灵敏准确、实时在线、重现性好等特点,可用于名贵药材——鹿茸的活性部位的筛选,也为药效物质的研究提供了一个新的研究思路和方法.     

Dispersion-convolution model for simulating peaks in a flow injection system

A dispersion-convolution model is proposed for simulating peak shapes in a single-line flow injection system. It is based on the assumption that an injected sample plug is expanded due to a "bulk" dispersion mechanism along the length coordinate, and that after traveling over a distance or a period of time, the sample zone will develop into a Gaussian-like distribution. This spatial pattern is further transformed to a temporal coordinate by a convolution process, and finally a temporal peak image is generated. The feasibility of the proposed model has been examined by experiments with various coil lengths, sample sizes and pumping rates. An empirical dispersion coefficient (D*) can be estimated by using the observed peak position, height and area (tp*, h* and At*) from a recorder. An empirical temporal shift (Phi*) can be further approximated by Phi*=D*/u2, which becomes an important parameter in the restoration of experimental peaks. Also, the dispersion coefficient can be expressed as a second-order polynomial function of the pumping rate Q, for which D*(Q)=delta0+delta1Q+delta2Q2. The optimal dispersion occurs at a pumping rate of Qopt=sqrt[delta0/delta2]. This explains the interesting "Nike-swoosh" relationship between the peak height and pumping rate. The excellent coherence of theoretical and experimental peak shapes confirms that the temporal distortion effect is the dominating reason to explain the peak asymmetry in flow injection analysis.