无熟料水泥混凝土的物理力学特性

无熟料水泥混凝土(NSC)是用水淬高炉矿渣(GBFS)和激发剂的混合物作为胶凝材料而配制的新型混凝土,其性能取决于GBFS的碱度、化学成分、玻璃化率以及激发剂的种类和数量。为此,以磷石膏作为GBFS的激发剂来配制NSC后,采用与普通水泥混凝土(简称OPC)对比的方法、进行了和易性、强度及其与钢筋黏结强度的试验探讨。结果表明:NSC的和易性优于OPC;早期强度主要来源于钙矾石并接近OPC,长期强度则主要来源于C-S-H水化物且远远超过OPC。     

Electrodeposition and pseudocapacitive properties of tungsten oxide/polyaniline composite

Composite films of tungsten oxide (WO₃) and polyaniline (PANI) have been electrodeposited by cyclic voltammetry in a mixed solution of aniline and precursor of tungsten oxide. Surface morphology and chemical composition of WO₃/PANI composite are characterized by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The influence of H₂O₂ on the electrodeposition of WO₃/PANI composite film is also investigated. Cyclic voltammetry (CV), chronopotentiometry (CP) and electrochemical impedance spectroscopy (EIS) results show that WO₃/PANI composite film exhibit good pseudocapacitive performance over a wide potential range of −0.5 to 0.7 V vs. SCE with the specific capacitance of 168 F g⁻¹ at current density of 1.28 mA cm⁻² and energy density of 33.6 Wh kg⁻¹, which is 91% higher than that of similarly prepared PANI (17.6 Wh kg⁻¹). An asymmetric model capacitor using WO₃/PANI as negative and PANI as positive electrodes over voltage range of 1.2 V displays a specific capacitance of 48.6 F g⁻¹ and energy density of 9.72 Wh kg⁻¹ at the power density of 53 W kg⁻¹, which is two times higher than that of a symmetric capacitor modeled by using two PANI films as both positive and negative electrodes.     

Heteropoly acid catalyzed hydrolysis of glycogen to glucose

Complete conversion of glycogen to glucose is achieved by using H₃PW₁₂O₄₀·nH₂O (HPW) and H₄SiW₁₂O₄₀·nH₂O (HSiW) as catalysts for the hydrolysis under optimized hydrothermal conditions (mass fraction of catalyst 2.4%, 373 K and 2 h reaction time). The reusability of the catalyst (HPW) was demonstrated. In addition to carrying out the glycogen hydrolysis in an autoclave, other novel methods such as microwave irradiation and sonication have also been investigated. At higher mass fraction of the heteropoly acids (10.5%), glycogen could be completely converted to glucose under microwave irradiation. Sonication of an aqueous solution of glycogen in the presence of HPW and HSiW also yielded glucose. Thus, heteropoly acids are efficient, environmentally friendly and reusable catalysts for the conversion of glycogen to glucose.     

Electrochemical synthesis of WO3/PANI composite for electrocatalytic reduction of iodate

Composite film of polyaniline (PANI) and tungsten oxide (WO₃) was electrodeposited by cyclic voltammetric technique from a solution of aniline and tungstic acid. The obtained WO₃/PANI film displayed a significant enhancement of electrocatalytic activity for iodate reduction and a better stability than that of pure WO₃ and PANI films. Result of amperometric experiment revealed a good linear relationship with concentration of IO₃⁻ from 20 to 500 μM, with a high sensitivity of 0.54 μA/μM and a detection limit of 2.7 μM for the determination of iodate. This composite film was also successfully applied in determination of iodate in commercial table salt.     

任意摆角单摆运动周期的一个近似公式

利用线性插值的方法，提出了在一个任意摆角条件下的单摆运动周期的近似公式.同时利用Mathematica软件，对在不同摆角下的单摆振动周期进行了精确计算，并绘制出了精确解的曲线.将推导出的近似公式与该精确解及其他近似公式进行了对比.结果表明：该近似公式的推导为解决类似问题提供了一个较好的思路，其结果与精确解也符合得很好.而且，从推导过程得出的图像中可比较直观地看出单摆作简谐振动所需的小角度条件.     

中国台湾地区梳棉机研究概述

从静电技术在梳棉机的应用,梳棉机的基本作用,发展小型梳棉机等几个方面介绍了中国台湾地区梳棉机研究的概况,对梳棉机工作者了解台湾地区梳棉机研究情况可能会有一定的参考价值。