氨基酸的高效毛细管区带电泳电导检测的研究

用阴离子交换膜制作的导电接口连接毛细管和自制和微电导池检测器，在自选组装的是民泳装置上研究了几种氨基酸混合流的电泳分离和柱后电导检测，了缓冲体系及其浓度、ｐＨ值、电泳电压等对氨基酸分离的影响。     

纺织整理废水电导值影响因素的研究

分别采用DDS-Ⅱ型电导仪和3700E型感应式电导仪对HCl/H2SO4/NaOH标准溶液的电导值进行了测定,并探讨了温度、浓度以及杂质含量对电导值的影响。结果表明,相比于DDS-Ⅱ型电导仪,3700E型感应式电导仪可以更好地用于纺织整理废水中酸碱的在线检测,并根据温度、浓度与电导值之间的关系建立了适用于一定温度和浓度的电导数学模型,进一步提出纺织整理废水中杂质的影响不容忽略。     

β-氨基酸Schiff碱铜(Ⅱ)配合物的合成及表征

合成了两种邻菲啉、β-氨基酸Schiff碱铜(Ⅱ)配合物:[Cu(sal-β-phe-phen)]和[Cu(sal-β-ala-phen)]·H2O,用元素分析、摩尔电导、红外光谱、电子吸收光谱、差热和热重等分析手段对配合物进行了表征,并对配合物抗菌活性进行初步研究。     

离子色谱-直接电导法同时测定常见氨基酸和无机阳离子

采用阳离子交换色谱-直接电导法测定部分常见氨基酸和无机阳离子,以酒石酸和吡啶二羧酸溶液为淋洗液,利用阳离子色谱系统等度洗脱,通过对色谱分析条件的优化,无需衍生化即可同时测定谷氨酸、丙氨酸、甲硫氨酸、亮氨酸、苯丙氨酸、赖氨酸及Na+, NH4+, K+, Ca2+和Mg2+. 选择12 min内出峰的5种氨基酸和3种无机阳离子进行定量分析,结果表明,其相对标准偏差RSDn=5≤4.690%,标准曲线的线性相关系数不低于0.9984,检出限在0.27~10.34 mg/L之间. 以建立的方法测定味精等电母液中的氨基酸,结果显示,氨基酸的回收率为88.7%~107.2%.     

钒酸盐玻璃的电导性质

本文根据玻璃的半导体性质研究了Na_2O、CuO、CaO、BaO、B_2O_3、SnO_2等氧化物在磷钒酸盐玻璃中对电导率的影响。计算了各种玻璃的电导激活能。 从晶体化学观点出发,对组成与电导性质之间的关系,联系玻璃结构作了说明。参照晶态氧化物的电导机构,我们认为这个理论可引用来解释磷钒酸盐的电导本质。 玻璃的电子电导主要是由钒离子的变价来进行的。若其中有可迁移的阳离子存在,则离子电导将显示它的重要地位。实验中证实,钙离子在较高温度下,也可以移动并成为电导的主要载流子。 按照磷钒酸盐玻璃的电导事变化规律,可使我们知道怎样去控制这类玻璃材料的电导性质,以及怎样去预期获得他种良好导电的玻璃。     

测量液体电导的两种新方法

介绍两种用于液体电导测量的新方法,给出具体的电路实现并分析两种电导测量方法各自的特点。基于锁相放大原理的测量方法可在低速测量的情况下实现液体电导的高分辨率检测,而基于双极性脉冲电流激励技术的电导测量方法能在保证一定测量精度的同时实现高速度的电导测量。最后对两种液体电导测量方法的优点、局限性以及进一步改进的意见进行了讨论。     

PbO-Fe2O3-P2O5系统半导体玻璃的电导性能研究

研究了(0.4-x)PbO—xFe2O3—0.6P2O5半导体玻璃的电导性能。首先熔制了SF系列玻璃,测定了玻璃的氧化还原指数和电导率,并计算了铁离子浓度和铁离子的平均距离。讨论了玻璃组成、熔制条件以及氧化还原指数对电导的影响,揭示了它们的电导性质不仅与组成有关,而且与铁离子的氧化-还原状态有关。随着熔制温度的升高,氧化还原指数提高,从而使电导增加。研究表明,该半导体玻璃的电导机制符合Mott的小极化子跳跃理论。     

ZnCr2O4-V2O5-Li2O-ZnO湿敏材料的感湿机理

测试了ZnCr2O4-V2O5-Li2O-ZnO材料的感湿特性,与水的导电特性进行比较,二者的电导值出现看似矛盾的结果。通过对电子电导和离子电导的分离测试,提出了该材料感湿状态下高电导的形成机理,从而解释了上述实验结果。     

热力系统锅炉水相电导率温度响应参数的解析

为了探讨离子在实际锅炉水相与取样水之间迁移转化规律的异同,找出适用于锅炉水相电导率较精确的还原方法.选取不同的Na2PO4、NaOH、Na2HPO4配比的水溶液模拟六种典型工况下的锅炉水相,跟踪测试了系统在20～70℃(△T=5℃)范围内电导率随温度变化.求出了各水相的电导温度系数和电导活化能.实验及计算结果表明:(1)各水相电导温度系数存在明显差别;(2)锅炉水相的电导温度系数取各离子浓度和电导温度系数乘积的加权平均值较为准确;(3)电导活化能是反映炉水中离子迁移和反应能力的一个重要的表征指标.     

电导法与静态阻垢法测定阻垢剂阻垢性能的比较研究

采用电导法和静态阻垢法对聚天冬氨酸（PAsP）阻CaCO3垢的性能进行了测定。实验结果表明：当PASP浓度在10～40mg／L范围内,随着PASP浓度的增加,阻垢效果不断增强,随后趋于平稳。电导法与静态阻垢法对阻垢剂阻CaCO3垢的评价结果具有一致性,电导法测定PASP对CaCO3垢的阻垢性能具有快速、简单、易行等优点。且实验表明,电导法的RSD〈0.01,而静态阻垢法为0．0824,说明电导法的重要性优于静态阻垢法。     

Measurement of thermal conductivity of polymer melts by the line-source method

An apparatus has been developed for the measurement of thermal conductivity of polymer melts. Based on the transient “line source method,” it is ideally suited to these materials because measurements can be made quickly, before the onset of thermal degradation. Also, little or no sample preparation is required. A number of commercial polymers have been tested, including some glass-fiber filled composites.     

测定锅炉水和冷却水中氯离子的新方法探讨

阐述了用全自动电位滴定仪测定锅炉水和冷却水中氯离子(Cl-)含量的新方法。新方法采用梅特勒-托利多仪器公司的DL58全自动电位滴定仪,并选择DM141银复合电极为检测器,用AgNO3作为滴定剂进行全自动滴定分析。新方法与传统的Cl-测定法(摩尔法、佛尔哈德法、法扬司法等)和Cl-选择电极法相比,测定结果更加准确,方法的重现性和精确度更高,且简单快捷,试剂的消耗成本降低,可广泛应用于锅炉水和冷却水、生活污水、部分工业污水、雨水、饮用水等方面的分析测定。     

THE THERMAL CONDUCTIVITY OF SOME REFRACTORIES1

The problem of measuring the thermal conductivity of materials up to high temperatures has been studied, especially in regard to the sources of error. This investigation has shown that many of the previous determinations of thermal conductivity may have had little precision due to a lack of appreciation of the errors involved. The values of thermal conductivity for a number of refractories are given, as obtained by a new type of apparatus designed to eliminate to a considerable extent the errors of measurement. However, it is believed that these values may have an error as high as ± 25 % for the better heat conductors; so there is still much work to be done in developing a method for measuring thermal conductivity with the precision usual in other physical measurements.     

Thin copper foil heater for measuring the thermal conductivity of polymers

A new and rather simple apparatus is described for measuring the thermal conductivity of insulating materials. The technique employs a double‐sided, copper‐coated plastic sheet, known as a printed circuit board, to generate a nearly uniform wall heat flux. Heating is achieved by passing an electrical current through the copper coating. Identical sample slabs are placed against opposite sides of the heater, and the combination is placed in a bath having constant and uniform temperature. When thermal equilibrium is reached, the temperature drops across the central portions of the sample slabs are measured with thermocouples. The one‐dimensional form of Fourier heat transfer equation is used to compute thermal conductivity from the observed quantities. In preliminary tests with polymer materials, equilibrium is reached within half an hour. It is estimated that the apparatus is capable of giving measurements accurate to within 5%, and experimental results are consistent with this estimate. Thermal conductivity values are reported for pure polyethylene (PE) and PE mixed with aluminum powder and carbon black. Also reported is the thermal conductivity of pure polycarbonate (PC) and PC mixed with carbon black. The results obtained with the present apparatus are consistent with previous findings. The characteristics of the apparatus make it especially suitable for academic laboratory instruction and for low temperature thermal conductivity measurements. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 12: 2823–2827, 2003     

液化石油气中二甲醚的气相色谱分析

建立了利用填充柱测定液化石油气中二甲醚含量的气相色谱方法。采用水浴完全气化样品,气体进样六通阀进样,热导池检测器检测。定量标准曲线的相关系数大于0.999,最低检测限(S/N=3)为0.8%(V/V),该方法简便快速,已成功地应用于液化石油气样品的测定。     

Time-resolved small-angle light scattering for the study of phase separation kinetics in bisphenol-a polycarbonate/poly(methy methacrylate) blends

An automated, solid-state small-angle light scattering apparatus has been constructed for the investigation of polymers; the main features of this system are a bidimensional CCD (charge coupled device) detector with 12-bit resolution and custom-made, user-friendly software for the acquisition and treatment of the scattering data. The miscibility and phase separation kinetics of several bisphenol-A polycarbonate/poly(methyl methacrylate) blends have been investigated using this apparatus. It was found that the rate of phase separation can be altered significantly by replacing part of the polydisperse poly(methyl methacrylate) (PMMA) in the blends by monodisperse PMMA.     

THERMAL CONDUCTIVITY OF NONMETALLIC SINGLE CRYSTALS*

Theories of thermal conductivity in single crystals of non-metallics are given, and the apparatus used for experimentation is described. Experimental results obtained for a number of single crystals show the variation of conductivity with temperature and crystallographic direction. A minimum thermal conductivity as the temperature is increased is indicated, which agrees with the theory of A. H. Compton.     

Thermal properties of silicate esters

Fourteen dimethyldialkoxysilanes are prepared by reacting dimethyldichlorosilane with corresponding alcohols in the liquid phase. Their physicochemical properties are determined by standard methods and their tentative empirical formulae are elucidated. The thermal conductivity values of dimethyldialkoxysilanes are determined using a two slab guarded hot plate apparatus over a temperature range of 30–190°C. The thermal conductivity values of dimethyldialkoxysilanes calculated from empirical equations are found to vary from -14% to +19%. Because thermal conductivity is an important parameter in heat transfer calculations, and to minimise the deviation of the values, new equations involving easily measurable ultrasonic parameters have been formulated. The proposed equations have been tested for the series of dimethyldialkoxysilanes, tetraalkoxysilanes and polydimethylsiloxanes. The thermal conductivity values computed from the proposed equations are comparable with experimental thermal conductivity values. Further, an equation involving the calculation of thermal conductivity values at varying temperatures is also proposed.     

在高温高压下测定液体导热系数的方法

本文描述了在高温高压下快速测定液体导热系数的方法.温度和压力分别达到250℃和25.0MPa,以玻璃包封的热敏电阻作为加热元件,用桥路测定热敏电阻的dV/dt,由dV/dt计算介质的导热系数,每次测量时间为1.5秒,用六个已知导热系数的参考液体标定了装置,平均偏差小于±2%.该装置不仅可以测量有机液体,而且也可以测量导电液体或溶液.