多孔性接枝聚乙烯膜湿度传感器

本文将亲水性聚（2-丙烯酰胺基-2=甲基丙碳酸）作为支链,接技到多孔性PE膜表面,以制得的接枝膜为感湿膜,制作了湿度传感器。发现此传感器的电阻对数值随相对湿度呈线性规律变化。而且该传感器能耐水及其它恶劣环境,此外,该传感器长期稳定性也较好。     

用聚电解质作支链的接枝共聚物为感湿材料制作湿度传感器

将２－羟基－３－异丁烯酰氧丙基氯化三甲铵接枝到多孔性聚乙烯膜表面，合成接枝聚乙烯膜作感湿材料，制作的湿度传感器电性能随湿度而变化，具有线性度好，阻值变化范围适中，耐水性能好等特点。     

湿度传感器

本文分析了陶瓷类和聚合物湿度传感器的性能和感湿机理，并比较了这两大类传感器的特性。     

Nasicon系陶瓷湿敏材料和湿度传感器的研究

根据Nasicon相(Na3Zr2Si2PO12)具有低湿阻的特点,高温合成Nasicon相Na3-xZr2Si2-xP1 xO12(0≤x≤2),添加适量成孔剂和少量金属氧化物制成Nasicon4-1和Nasicon4-3两组陶瓷湿敏材料和湿度传感器。用直流电导法判定导电机制是以离子电导为主的离子-电子混合电导。用压汞法和SEM研究了湿敏材料的孔结构。两组湿度传感器的湿阻特性均为线性,Nasicon4-1传感器具有小的低湿度电阻,而Nasicon4-3具有高的感湿灵敏度。     

湿度传感器动态响应特性校准研究

介绍了湿度传感器动态响应特性校准工作的基本原理、湿度传感器校准装置的设计及校准时应注意的问题。     

一种共聚物膜制作的湿度传感器

本文将ＭＭＡ（甲基丙烯酸甲酯）与苯乙烯共聚，所得共聚物进行磺化反应，以最终产物为感湿膜制成温度传感器，其电阻随相对湿度的变化而成指数关系变化。该传感器具有线性度好、耐湿、耐水、耐污染和长期稳定性好等特点。并且其阻值变化适中，能用常用仪表检测。     

多孔性接枝聚乙烯膜湿度传感器

本文将亲水性聚（２－丙烯酰胺基－２－甲基丙磺酸）作为支链,接枝到多孔性ＰＥ膜表面,以制得的接枝膜为感湿膜,制作了湿度传感器。发现此传感器的电阻对数值随相对湿度呈线性规律变化。而且该传感器能耐水及其它恶劣环境,此外,该传感器长期稳定性也较好。     

Application of polymer‐coated quartz crystal microbalance (QCM) as a sensor for BTEX compounds vapors

A sensor based on the technique of a quartz crystal microbalance (QCM) was developed for the detection of organic vapors such as benzene, toluene, ethylbenzene, and xylenes (BTEX compounds). Detection was based on the adsorption of organic vapors on a thin layer of polydimethylsiloxane (PDMS) coated at the surface of AT‐cut gold‐coated quartz crystal electrodes. The frequency shifts due to the sorption of BTEX compounds were measured. Calibration graphs were constructed by plotting the frequency changes (ΔF/Hz) against the concentration of organic compounds. Using this method, the detection of these organic vapors was carried out at the ppm level. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 1062–1066, 2001     

High‐sensitivity QCM with multielectrode piezoelectric quartz crystal design

The ideal linear elastic, small hysteresis phenomenon makes the quartz resonator uniquely useful for Quartz Crystal Microbalances (QCM). Enhanced high‐precision integrated quartz crystal resonators were designed based on the common‐mode rejection principle. The internal stress of quartz crystal on the force was analyzed for the multielectrode design, and the point which located the electrode (diameter is 1 mm) is distributed on the circle from 4 mm to the center of the quartz crystal plate, and the orientation angle φ=60°. The 15 group difference frequency signals were first done the difference frequency processing and then superposition by information fusion technology. The final force sensitivity coefficient of integrated resonator is 11223 Hz/N. It is 10 times than the single resonator. The frequency stability of each electrode is shown 10^?10 order of magnitudes.     

液晶乳化体保湿性能研究

采用保水测试(体外法)为主,人体法为辅的测试方法对不同乳化体的保湿性能进行评价。在恒温匣湿体外条件下,记录乳化体余水率与失水速率,发现二者存在正线性相关关系并得出关系式(α=0.05)。同时人体法实验结果与体外法结果相符,提出可以利用关系式的斜率反映乳化体保水性能差异,所制得的液晶乳化体系保湿性能优于非液晶乳化体系。     

Natural convection heat and moisture transfer with thermal radiation in a cavity partially filled with hygroscopic porous medium

This article deals with natural convection heat and moisture transfer with thermal radiation in a cavity partially filled with hygroscopic porous medium. The governing equations for the momentum and heat transfer in both free fluid and hygroscopic porous medium and moisture content transfer in hygroscopic porous medium were solved by the finite element method. The radiative heat transfer is calculated by making use of the radiosity of the surfaces that are assumed to be grey. Comparisons with experimental and numerical results in the literature have been carried out. Effects of thermal radiation and Rayleigh number on natural convection and heat transfer in both free fluid and porous medium and moisture content transfer in porous medium were analyzed. It was found that surface thermal radiation can significantly change the temperature and moisture content fields in the regions of free flow and porous medium. The mean temperature at the interface decreases, the temperature and moisture content gradients are created on the upper two corners of the porous medium region, and the moisture content in the porous medium decreases in the porous medium as Ra increases.     

表面辐射对部分填充吸湿性多孔介质的封闭腔体内热湿耦合传递的影响

根据多孔介质热质传递原理, 基于有限元的方法数值分析了具有表面热辐射的部分填充吸湿性多孔介质的封闭腔体内部自然对流流动及热湿耦合传递过程, 探讨了表面发射率、Rayleigh数和Darcy数等参数对封闭腔体内部自然对流流动及热湿耦合传递过程的影响, 研究结果表明, 壁面热辐射的作用可以提高多孔介质内部的温度, 而且随着表面发射率的增大, 多孔介质内部的水分逐步向其右上角迁移和聚集。另外, Darcy数、多孔介质与空气的热导率比对方腔内部多孔介质的热量传递和水分迁移影响较小。     

Self-assembly of a liquid crystal ABA triblock copolymer in a nematic liquid crystal solvent

An ABA type triblock copolymer, consisting of liquid crystalline polymer (LCP, poly(4-cyanobiphenyl-4-oxyundecylacrylate)) ‘A’ end blocks and a deuterated polystyrene (dPS) ‘B’ mid block (LCP–dPS–LCP) was successfully synthesized by atom transfer radical polymerization (ATRP). The number average molecular weight (M_n) of LCP–dPS–LCP was LCP (7.1 K)–dPS (19.4 K)–LCP (7.1 K) with a polydispersity index (PDI) of 1.41. LCP–dPS–LCP was self-assembled in a nematic liquid crystal solvent of 4-pentyl-4′-cyanobiphenyl (5CB) into spherical micelles with a LCP corona and a dPS core, in which dPS was folded to produce a V-shape structure. Micellar structures of LCP–dPS–LCP in 5CB were examined by small angle neutron scattering at various block copolymer concentrations and temperatures using a curve fitting method. The critical micelle concentration was 0.25 wt% and the self-assembled micelles dissociated into unimers at 33 °C, which is lower than the nematic to isotropic transition temperature (T_ni) of 5CB (36 °C). The entropic penalty imposed on dPS by the ordered nematic state of the 5CB solvent caused phase separation of the flexible dPS block to form micelles, which vanished above the T_ni of the 5CB solvent. Magnetic field-induced global orientation of 5CB revealed the structure of the dPS core of the micelle to be prolate (an elongated sphere) oriented with its long axis along the direction of the applied magnetic field.     

石英晶体谐振器用高导电率导电胶粘剂的研制

简要介绍了一种高导电率导电胶的研制方法,论述了导电促进剂对性能的影响。实验结果证明,此国产导电胶性能良好,完全可以替代进口导电胶应用于石英晶体谐振器生产中。     

Monitoring of formation and redox transformations of poly(Methylene blue) films using an electrochemical quartz crystal microbalance

An electrochemical quartz crystal microbalance and cyclic voltammetry have been used to monitor the growth of poly(methylene blue) films on gold during potential cycling between −0.6V and 1.0V vs. sce in sodium phosphate buffer (pH 8.2) and Na₂SO₄ solutions. Both the adsorption/desorption of monomer methylene blue and the formation of poly(methylene blue) film can be followed by microgravimetry. The response of the polymer films is significantly separated from that of the monomer species in solution. It has been proved that anion sorption/desorption occur during the redox transformation of the polymer, while cations play no role. Preliminary results on the complex protonation/deprotonation equilibria are also discussed.     

利用石英晶体微量天平测定紫杉醇在二氧化碳中的溶解度

A quartz crystal microbalance (QCM) is used to determine the phase equilibrium of paclitaxel-carbon dioxide system in the pressure range of 0-11 MPa and at temperatures of 35 °C,40 °C and 45 °C.The experimental results indicated that gaseous CO2 could be absorbed poorly into paclitaxel.The swelling of paclitaxel film in CO2 was observed before paclitaxel dissolved into supercritical carbon dioxide (ScCO2) with the increase of pressure.It was found that ScCO2 was not a good solvent for paclitaxel.The mole fraction of paclitaxel in ScCO2 was in the range of (4.5×10-9)-(7.8×10-9) under all our experimental conditions.Therefore,a much higher pressure than the CO2 supercritical point and/or a cosolvent must be used in any processes wherever paclitaxel dissolution in ScCO2 is required.     

石英晶体微天平(QCM)在超临界CO2过程中的应用

超临界流体技术是绿色化学的一个重要领域,由于高压的限制,传统检测手段很难应用于过程中涉及的物理和化学性质数据的测定,严重影响了超临界技术的研究与应用。石英晶体微天平(QCM)作为一种新型的介观级微称重技术,适用于高温高压等极端条件,具有测量精度高的优点。本文介绍了石英晶体微天平技术应用的基本理论及其特点,并重点回顾和展望了该技术在超临界CO2中的应用。