High-performance dispersant of coal–water slurry synthesized from wheat straw alkali lignin

Environmental concerns have stimulated interest in utilizing plant-derived materials in various industrial fields. The main objective of the present study was to synthesize a new type of high-performance lignin series dispersant of coal–water slurry (CWS) from wheat straw alkali lignin (WAL), and determine the affecting factors in the reaction and the application performance for CWS preparation. The experimental results showed that the inherent viscosity and the sulfonic group content of the modified wheat straw alkali lignin (MSL) are the key factors affecting its dispersing effect for CWS. In the reaction, the reactant mass concentration and the sulfonating agent amount were changed to obtain the MSL with different inherent viscosities and sulfonic group contents, and the MSL with intermediate inherent viscosity (6.0 ml/g) and higher sulfonic group content (1.80 mmol g^− 1) was found to have excellent dispersing effect for CWS. The MSL obtained from optimized process was used as dispersant for CWS preparation, the studies of the properties of CWS showed that MSL has similar dispersing effect with naphtalenesulfonate–formaldehyde condensate, and far better dispersing effect than lignosulphonate. Recently this kind of new dispersant has been applied in several power plants in China.     

Swelling behavior of poly(sodium acrylate)/kaoline superabsorbent composite

Using partly neutralized acrylic acid as monomer, kaoline ultrafine powder as filler and N,N′‐(dimethyl)acrylamide as crosslink agent, poly(sodium acrylate)/kaoline superabsorbent composite was synthesized by aqueous solution polymerization method. Using the superabsorbent composite as collagen, a hydrogel was prepared. The influence of the neutralization degree of superabsorbent collagen, the compositions, the concentration, and the pH value of exterior solution on the swelling behavior of the hydrogel was investigated. It was found that the swelling capability of the hydrogel depended on the groups on the collagen. The swelling capability of the hydrogel relied on the ionic intensity, molecular polarity, molecular volume, as well as the concentration of exterior solution. When the pH value of exterior solution was equal to seven, the hydrogel has a maximum swelling value of 800 times. POLYM. ENG. SCI. 46:324–328, 2006. © 2006 Society of Plastics Engineers     

塑料挤出机主辅电机联动系统设计

本文在分析国内外挤出机生产线主辅电机同步联调特点的基础上,提出了一种实用的联调控制系统设计方案,控制系统设计采用纯硬件方式,可以广泛适用于国内未采用同步联调技术的挤出生产线,进行技术改造,对原有设备改动极小,具有很高的性能/价格比。     

牙舟泥哨

牙舟泥哨作为民间陶制玩具在数百年的发展中逐渐形成了自己的风格和个性，在造型、审美上带有独特黔南地方特色。本文从造型和审美的角度对牙舟泥哨进行了分析。     

Experimental Study on the Hydrodynamics and Mass Transfer Characteristics of Ultrasonic Loop Airlift Reactor

The promoting effect of ultrasonic wave on the hydrodynamics and mass transfer characteristics of the loop airlift reactor was studied. The gas holdup, liquid circulation velocity, mixing time and overall volumetric mass transfer coefficient were examined and compared, with and without ultrasonic wave in the reactor. The experimental results show that ultrasound has almost no notable effect on the gas holdup, but has a tendency to decrease gradually the liquid circulation velocity and increase the overall volumetric mass transfer coefficient; and the effect on the mixing time is relatively complex. At low superficial gas velocity, the low powered ultrasound promotes the radial mixing of fluid; with the ultrasonic power increasing, ultrasonic vibration obstructs the axial mixing of fluid. Moreover, the effect of ultrasonic wave on the mixing time gradually decreases with the increase in the superficial gas velocity. Therefore there exists an optimal ultrasonic power for hydrodynamics and mass transfer. Correlations were also proposed for the hydrodynamics and mass transfer characteristics of the reactor.     

基于差分光电技术的人血清PSA检测算法研究

血清前列腺特异性抗原(PSA)是前列腺癌早期诊断的重要指标之一.通过采用免疫层析金标试纸和差分光电技术检测PSA浓度的方法,并用分段线性拟合方法分别拟合浓度为0.5～5 、5～50 和50～100 ng/mL范围内PSA浓度和T/C比值的关系.标定结果显示,在5～50 ng/mL范围内PSA浓度和T/C比值的线性相关性较好,其调整决定系数R2为0.924 27,而在该范围之外,它们的线性相关性都较差,不适合用作PSA检测.在浓度为5～50 ng/mL范围内做了11组检测实验,检测值和真实值的相关系数达到了0.910.实验证明,采用差分光电技术检测PSA浓度并用分段线性拟合方法做数据处理是可行的     

液压仿真技术的应用与发展

本文在简单回顾液压仿真技术的发展之后,着重介绍了仿真技术及其在液压领域的应用,论述了液压建模与仿真技术的方法和几个关键问题,并从不同的侧面介绍了一些软件,最后综述了液压仿真技术未来的发展趋势。     

基于Web的高校在线心理咨询系统设计

近几年,大学生心理健康问题已经成为无法回避的问题。由于心理咨询的特殊性,传统的咨询模式在洞察心理疾病、保护个人隐私和提高服务效益方面受到种种因素的制约。而基于Web的高校在线心理咨询系统是与现代IT技术密切结合的远程心理咨询系统,能够轻易地解决传统咨询模式存在的不足。既能实时为大学生提供比较专业的心理咨询服务,又能保护学生的隐私和维护自尊心,为提高他们主动接受咨询的积极性提供了全新的方式和途径。     

Evaluation of PLGA/chitosan/HA conduits for nerve tissue reconstruction

A micro-envioment for nerve cells and tissue growth were designed and constructed via surface modification of poly(L-lactide-co-glycolide)(PLGA) with chitosan and hydroxyapatite(HA). The poly(L-lactide-co-glycolide)/chitosan/hydroxyapatite (PLGA/chitosan/HA) conduits were manufactured by a combined solvent casting and particulate leaching technique. The conduits were highly porous with an interconnected pore structure and 76.5% porosity. Micropores with 50–100 micrometer diameter were formed in the conduits. In vivo application of PLGA/chitosan/HA conduits for reconstruction of 10 mm sciatic nerve defect was assessed by the walking track analysis, the quantifying of the wet weight of tibialis anterior muscle and the histological assessment. The conduits in host rats in vivo can not only be an effective in promoting regenerating of nerves but can also lead to favorable nerve functional recovery. Funded by the National Natural Science Foundation of China(No.50774096)     

北京地区中小套型住宅居住需求及对策研究

通过对北京地区中小套型住宅居住实态调研结果进行数据统计分析,探讨了住户在住宅使用过程中存在的共性问题,分析了住户的使用需求,并提出了相应的合理化建议．文中还选取两个典型实例进行改造,为以后住宅改造与设计提供了一定的借鉴与参考．