High‐Tech‐Cellulose‐Funktionspolymere nach dem ALCERU®‐Verfahren

Functional High‐Tech‐Cellulose materials by the ALCERU® process Cellulose is one of the eldest materials of mankind. While the use of cellulose in former times was focused on application as a more construction or as a more textile material at present time the application profile turns to a more functional material using the ALCERU® process. Shaping of pure cellulose dissolution in NMMNO permits the manufacturing of materials for upholstery, filtration or biodegradable film strips having an uniform cross section. Fibreds, which can be applied in several packaging materials, are available using different techniques for regeneration cellulose. A great field of innovative functional cellulose materials is opened up by addition of several functional additives to cellulose dissolution. In this way piezo‐electrical conductive cellulose fibres (PZT) or high‐temperature filtration membranes are to be generated if one adds special types of ceramic powders. Above all PZT green fibres are applied in more recent uses as sensors or actuators. Electrically conductive cellulose fibres or filaments, which can be also used in the textile chain, can be prepared adding conductive carbon black to a cellulose dope on the same way, too. Cellulose material having adapted conductivity to different application is available by adding an exact defined amount of carbon black to cellulose dissolution. Finally cellulose beads can be manufactured by means of varied shaping technique. The beads are showing variable particle sizes and narrow pore size distribution. These properties open up very interesting application in the field of human blood purification or chromatography.     

基于电容测量和PCA法的两相流相浓度检测方法

介绍利用电容层析成像系统阵列传感器结构和采样特点,引入主成分分析法(PCA)求取两相流相浓度的新方法.对大量测量值样本进行统计分析后,求出用测量值第一主成分求取相浓度的经验公式,仿真及静态实验表明:两者之间有着良好的对应关系,其测量结果不受两相流流型的影响,是一种有较好应用前景的测量方法.     

光纤Bragg光栅监测钢筋混凝土结构应变的实验研究

研究了光纤Bragg光栅在钢筋混凝土结构应变监测中的应用。对其应变、温度灵敏系数进行标定,将其埋设在钢筋混凝土梁内,实现对结构内部应变的监测,并对其工作状态做出评价。实验结果与理论值、传统监测手段监测结果一致。研制出一种钢管封装Bragg光栅温度传感器监测温度,对光纤Bragg光栅的应变与温度的同时测量进行了研究。     

纳秒级上升时间的高压脉冲群电源

按照IEC 61000-4-4/GB 17626.4—1998的要求，首先应用PSPICE仿真确定电路中各元件的参数值，然后基于拉普拉斯变换用MATLAB求解二阶电路验证各元件参数。在此基础上研制了一台以开关电源作为高压直流电源、以氢闸流管作为主控开关的脉冲群电源。该电源体积小、重量轻、效率高、成本低廉。试验结果表明，其输出信号符合标准要求，可用于快速瞬变脉冲群抗扰度试验。     

用于平场光谱仪的非球面全息凹面光栅设计

基于全息凹面光栅理论和ZEMAX软件,设计了一种用于平场光谱仪的消象差平场非球面全息凹面光栅。与采用相同口径、相同相对孔径的全息凹球面光栅构成的平场光谱仪比较,在入射狭缝宽度相同的情况下,该光栅所构成的平场光谱仪的分辨率得到明显提高。同时,利用较大相对孔径非球面全息凹面光栅,可使平场光谱仪的结构更紧凑,从而可实现平场光谱仪的小型化。     

Synthesis and aqueous solution behaviors of sodium sulfonate‐terminated dendritic poly(ester‐amine)

Sodium sulfonate‐terminated dendritic poly(ester‐amine) (SPEA) was synthesized by sulfonation of acrylic double bond‐terminated dendritic poly(ester‐amine) (APEA) with sodium hydrogen sulfite (NaHSO₃) in mixture of diglycol and 2‐butanone under normal pressure. The structure of SPEA was characterized by IR, ¹H‐NMR, and elemental analysis. SPEA was water‐soluble. 1.0–40.0% (mass) SPEA aqueous solutions appeared as dilatant fluid. When pH value varied from 1.5 to 12.0, the viscosity of 1–5% (mass) SPEA aqueous solutions changed very small, and the electric conductivity almost kept stable within pH 3.0–10.0. The relationship between the viscosity and the concentration of SPEA water solutions was similar to that of NaCl water solutions. The surface tension of SPEA water solutions was lower than that of polyethylene glycol 2000 water solutions with the same concentration. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Polyaniline-multiwalled carbon nanotube composites: Characterization by WAXS and TGA

Polyaniline/carboxylated multi-walled carbon nanotube (PAni/c-MWNT) nanocomposites have been synthesized by micellar aided emulsion polymerization with various c-MWNTs compositions, viz., 0.5, 1, 5, and 10 wt %. The microcrystalline parameters such as the nanocrystal size (〈N〉), lattice strain (g), interplanar distance (d_hkl), width of the crystallite size distribution, surface weighted crystal size (D_s), and volume of the ordered regions were calculated from the X-ray data by using two mathematical models, namely the Exponential distribution and Reinhold distribution methods. The effects of heat ageing on the microcrystalline parameters of the PAni/c-MWNT nanocomposites were also studied and the results are correlated. The thermal stability and electrical resistivity of the PAni/c-MWNT nanocomposites were examined with thermogravimetric analysis (TGA) and a conventional two-probe method. The TGA data indicate that the thermal stability of the nanocomposites improved after the incorporation of c-MWNTs. The influence of temperature on the resistivity of the nanocomposites was also measured. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci 2008     

γ射线对叶组织电阻变化的影响及动态分析

测试了水稻和烟草两种叶片经不同剂量的^60Co γ射线辐照处理后，组织电阻及离子外渗的动态变化情况。研究结果表明：当超过一定的剂量阈值后，随着辐照剂量的增加，两种植物的叶组织电阻均呈现先上升、后下降的变化规律；叶组织电阻的改变与离子外渗的变化趋势并不一致；用测量叶组织电阻的方法可以较灵敏地体现出植物对γ射线的动态反应情况。运用电生理学的基础理论对上述生理现象的产生原因从机理上进行了分析与探讨。     

一种基于FBG和LPG的温控报警模型

文章依据FBG温度传感的原理以及LPG滤波技术,提出了一种新的光纤光栅温度报警模型.用MATLAB对系统所采用的方法进行了模拟,结果表明该系统能满足温度报警的要求.     

Chalcogenide Glasses Based on Germanium Disulfide for Second Harmonic Generation

High second‐order susceptibilities are created by thermal poling in bulk germanium disulfide based chalcogenide glasses. Experimental conditions of the poling treatment (temperature, voltage, time) were optimized for each glass composition. The second‐order nonlinear signals were recorded by using the Maker fringes experiment and a second‐order coefficient χ⁽²⁾ up to 8 pm V^–1 was measured in the Ge₂₅Sb₁₀S₆₅ glass. This value is obtained using a simulation based on accurate knowledge of the thickness of the nonlinear layer. Two mechanisms are proposed to explain the creation of a nonlinear layer under the anode: the formation and the migration of charged defects towards the anode may mainly occur in Ge₂₀Ga₅Sb₁₀S₆₅ and Ge₂₅Ga₅S₇₀ glasses, whereas the migration of Na⁺ ions towards the cathode may be responsible for the accumulation of negative charges under the anode in Ge₃₃S₆₇ and Ge₂₅Sb₁₀S₆₅ glasses. Different electronic conductivity behaviors seem to be at the origin of the phenomenon. In parallel, the potential effect of the poling treatment on the structural and electronic properties is studied using Raman spectroscopy and secondary ion mass spectroscopy measurements.