光散射技术及其在高分子溶液研究中的应用

从重均分子量,均方旋转半径及平均扩散系数等高分子溶液中较为重要的几个物理量入手介绍了近十几年来光散射技术在高分子溶液领域的应用。同时,对静态光散射和动态光散射的几个重要参数以及其较为重要的公式也做了介绍。最后,还综述了光散射的发展简史、基本原理、有关实验的技术方法等内容。     

激光光散射法研究紫外光引发聚合

采用激光光散射法跟踪,发现紫外光引发聚合体系中有关助剂及紫外光强度对体系的光固化的诱导期和聚合反应速度具有明显的影响,而过程中使用硫醇类光固化促进剂具有最佳效果.同时发现,体系中表观聚合速度与紫外光强的1.2次方成正比.     

借烟碱与四苯硼钠反应的共振瑞利散射光谱测定烟碱的含量

研究了在HAc-NaAc缓冲溶液中烟碱与四苯硼钠反应生成的离子配合物产生的共振瑞利散射光谱,考察了其光谱特征、影响因素、适宜的反应条件和共存物质的影响。结果表明能应用光散射法测定烟叶中烟碱的含量,线性范围为2.21×10-6~1.48×10-5mol/L,检出限为6.16×10-7mol/L。     

利用多重光散射原理分析石油磺酸盐乳状液稳定性

对石油磺酸盐中的活性物质进行了提取,利用Turbiscan Lab稳定性分析仪多重光散射原理,对石油磺酸盐活性物与原油乳状液稳定特性进行了研究。测量了TSI稳定指数和粒径大小随时间的变化值,并通过光强度曲线变化分析静置后乳状液的状态变化。结果显示,转速越高TSI值越小,乳状液的稳定性越好。转速为4 000 r/min的乳状液平均粒径值最小,并且达到了极稳定乳状液粒径范围。根据光强度曲线的变化能够客观地反映出上浮、絮凝和聚结等一系乳状液体系的变化,较大地提高了效率和准确度。     

光散射测量技术在聚合物共混体系中的应用

首先介绍了聚合物共混体系混炼效果的传统表征方法,并分析了其局限性,在此基础上,对近年来逐步应用于聚合物多组分流变行为表征的光散射理论作了简要说明,概述了光散射在共混体系中相分离机理、相图以及形态学方面的应用,归纳分析了前人的一些主要工作成果,并对利用光散射测量振动力场下聚合物的混炼效果提出了自己的设想.     

曙红Y共振光散射法测定水中十六烷基三甲基溴化铵

利用共振光散射(RLS)技术,通过曙红Y与阳离子表面活性剂十六烷基三甲基溴化铵(CTAB)缔合产生强烈共振光散射增强效应,建立了一种测定阳离子表面活性剂CTAB的方法.实验结果表明,在pH=4.96的柠檬酸钠-盐酸缓冲介质中,采用吐温80作为曙红Y -CTAB体系的稳定剂,痕量CTAB的加入导致曙红Y在440～ 600 nm波长内的共振光强度增加,最大RLS峰位于538 nm处,其强度与CTAB的质量浓度在0～40 mg·L-1内成正比,检出限为0.012 mg·L-1.方法具有较高的灵敏度和良好的选择性,可用于水样中CTAB的测定.     

聚合物流动行为的光散射表征

简要地介绍了光散射原理及目前光散射技术在聚合物流变学的中的应用，归纳并分析了前人的一些主要工作成果。对于一些至今难以解释的实验现象提出了自己的一些认识，并对仍未有人涉足的振动力场下聚合物复杂流动光散射表征提出了新的设想。     

用光散射技术测量单个气溶胶微滴

作者在改进的电动平衡仪中悬浮单个气溶胶微滴,并使它受到1束激光照射.平衡仪上的1组光电列阵检测某一散射角范围内的散射光强度,另一个位于90°散射角处的光电倍增管连续测量共振光谱讯号.把所测得的实验数据与Mie理论计算值对照,就能非常精确地测定微滴的尺寸及其变化.     

浅谈高层建筑的消防应急照明系统的设计

文章论述了一般高层建筑物消防应急照明系统的设计,并通过长时间设计审核图纸对于消防应急照明系统设计中存在的问题进行了探讨,同时给出了解决办法。     

A method for evaluating the acceptability of light sources for clinical visual evaluation of cyanosis

The accurate identification of cyanosis depends on a number of factors including the quality and quantity of the lighting used. Requirements framed in terms of permissible limits on correlated colour temperature and colour-rendering indices worked satisfactorily for many years. However, the demise of halophosphate fluorescent lamp technology and its replacement with triphosphor technology has led to a need to reevaluate the former methods and acceptance criteria. The experimental methods of assessing previous light sources were long and involved. It is impractical to replicate them as each new light source or new lighting technology is developed. There is a need, therefore, for a colorimetric method of assessing light sources for this purpose. In this study, the spectral reflectance characteristics of blood with oxygen saturation levels from 95.6–0.7% are used to calculate colour changes with respect to a reference illuminant and correlated with the results of an extensive study, some years ago, of the influence of light sources in the detection of cyanosis. The results lead to a method of evaluation with a single value criterion for acceptability. The method lends itself to simple modeling techniques for phosphor mixtures and should simplify the design of appropriate fluorescent tube sources for clinical visual evaluation of cyanosis. © 1998 John Wiley & Sons, Inc. Col Res Appl, 23, 4–17, 1998.     

Phosphor-SiO2 composite films suitable for white laser lighting with excellent color rendering

Currently, phosphor composite films draw much attention in white laser lighting. In this work, we developed a novel phosphor-SiO₂ film via a mild method, which avoiding the phosphor degradation. Commercial colloidal silica was elected as the source of SiO₂ and acted as an inorganic binder, gap filler and a protective coating layer. Composite films comprised of mixed Lu₃Al₅O₁₂:Ce³⁺ and CaAlSiN₃:Eu²⁺ phosphors exhibit a uniform dense strucure and strong adhesion to the substrate. When excited by blue diodes laser, the optimal film exhibits excellent thermal stability (it maintains 89.1 % of the room-temperature intensity at 200 °C), super resistance against laser irradiation (12.9 W/mm²), a broad emission spectra with a full width at half maximum of 180 nm and a high luminous efficiency (183 lm/W). The color rendering index of the film was improved to 85. These outstanding properties indicate that the derived films are a promising candidate for white laser lighting.     

解吸水解废液中微量尿素分析方法讨论

中国石油宁夏石化公司的2套尿素装置先后采用甲醛法滴定分析、二乙酰一肟-氨基硫脲分光光度法、对二甲基氨基苯甲醛分光光度法进行解吸水解废液中微量尿素的分析.简述了上述3种分析方法的原理;对比了3种分析方法的优点和缺点;讨论了废液中的工艺介质对分析效果的影响程度.结果表明:①甲醛法滴定分析抗干扰能力强,是经典的分析方法;②若...     

水泥工厂的防雷设计

水泥厂防雷常由于处置不当,而留下安全隐患。水泥厂防雷除应有防直击雷保护外,还必须要考虑防雷电波侵入和雷电电磁脉冲感应的内部防雷保护。设计时应结合现行规范,针对水泥厂建筑的特点,对外部防雷装置和内部防雷装置进行统筹设计。其中,外部防雷装置可采用屋项金属构件作防雷接闪器;采用结构柱内主筋作防雷引下线;采用基础钢筋网作接地装置等。内部防雷装置可采用防雷等电位联结系统;以及采用共用接地系统,或加装过电压保护器等。实践证明,这些措施可有效保护水泥厂的建筑结构和设备遭受雷击破坏。     

水体中颗粒物主要检测方法综述

水中颗粒物主要用浊度指标表示,是衡量水体质量的重要且直观指标。文章介绍了浊度检测的方法,包括透射检测方法、散射检测方法和综合检测方法,并对其应用做了概述,为水质分析监测人员检测水中的浊度提供参考方法结。     

Advancement in materials for energy-saving lighting devices

This review provides a comprehensive account of energy efficient lighting devices, their working principles and the advancement of these materials as an underpinning to the development of technology. Particular attention has been given to solid state lighting devices and their applications since they have attracted the most interest and are the most promising. Solid state lighting devices including white light emitting diodes (LEDs), organic LEDs (OLEDs), quantum-dot LEDs (QLEDs) and carbon-dot LEDs (CLEDs) are promising energy efficient lighting sources for displays and general lighting. However there is no universal solution that will give better performance and efficiency for all types of applications. LEDs are replacing traditional lamps for both general lighting and display applications, whereas OLEDs are finding their own special applications in various areas. QLEDs and CLEDs have advantages such as high quantum yields, narrow emission spectra, tunable emission spectra and good stability over OLEDs, so applications for these devices are being extended to new types of lighting sources. There is a great deal of research on these materials and their processing technologies and the commercial viability of these technologies appears strong.     

Effect of microstructure of fluorinated acrylic coatings on UV degradation testing

This paper presents research results on the relationships between the microstructure and the performance/weatherability of fluoropolymer/acrylic coatings. We studied fluoropolymer/acrylic blends of identical composition, prepared as films using three different methods: 2-stage emulsion polymerization followed by latex film formation; cold-blending (physically mixing) acrylic and fluoropolymer latex dispersions followed by latex film formation; and solution casting using an organic solvent. We investigated the effects of the mixing method, and the level of acrylic in the blend on the microstructure/morphology and on the durability-related physical properties of the fluoropolymer/acrylic films. Small angle neutron scattering was performed to determine the microstructure/morphology of fluoropolymer-rich micro-domains in the coatings prepared using these three methods. The physical properties tested included the glass transition temperature, the crystallinity fraction, and the tensile strength. The mass loss rates observed during UV exposure testing correlate with the final microstructures of the films.     

Influence of soft segment composition on phase-separated microstructure of polydimethylsiloxane-based segmented polyurethane copolymers

Segmented polyurethane block copolymers were synthesized using 4,4′-methylenediphenyl diisocyanate (MDI) and 1,4-butanediol (BDO) as hard segments and various soft segments derived from poly(hexamethylene oxide) (PHMO) and poly(dimethylsiloxane) (PDMS)-based macrodiols and mixtures thereof. The microstructure and degrees of phase separation were characterized using a variety of experimental methods. Copolymers synthesized with the PDMS macrodiol and from PDMS/PHMO macrodiol mixtures were found to consist of three phases: a PDMS phase; hard domains; and a mixed phase of PHMO, PDMS ether end group segments and some dissolved hard segments. Two models were used to characterize the small-angle X-ray scattering from these copolymers: pseudo two-phase and core-shell models. Analysis using both methods demonstrates that as the PDMS content in the soft segment mixture increases, the greater the fraction of hard segments involved in hard domains than are dissolved in the mixed phase. Findings from analysis of the carbonyl region of FTIR spectra are also in agreement with greater hard/soft segment demixing in copolymers containing higher PDMS contents.