聚丙烯纤维性能及其在混凝土中的应用

在混凝土中掺加聚丙烯纤维能有效地提高混凝土材料的抗裂性、抗冲击性、抗冻性能、改善混凝土的抗疲劳特性。分析了纤维改性混凝土机理。介绍了聚丙烯纤维在混凝土中的应用。指出了聚丙烯改性混凝土的发展趋势以及加强高性能、多功能以及复合聚丙烯纤维改性水泥土研究的重要性。     

Synthesis and electrochemical characteristics of Al2O3-coated LiNi1/3Co1/3Mn1/3O2 cathode materials for lithium ion batteries

LiNi_1/3Co_1/3Mn_1/3O₂ cathode materials have been coated with Al₂O₃ nano-particles using sol-gel processing to improve its electrochemical properties. The X-ray diffraction (XRD) pattern of the as-prepared Al₂O₃ nano-particles was indexed to the cubic structure of the γ-Al₂O₃ phase and had an average size of ∼4 nm. The XRD showed that the structure of LiNi_1/3Co_1/3Mn_1/3O₂ was not affected by the Al₂O₃ coating. However, the Al₂O₃ coatings on LiNi_1/3Co_1/3Mn_1/3O₂ improved the cyclic life performance and rate capability without decreasing its initial discharge capacity. These electrochemical properties were also compared with those of LiAlO₂-coated LiNi_1/3Co_1/3Mn_1/3O₂ cathode material. The electrochemical impedance spectroscopy (EIS) was studied to understand the enhanced electrochemical properties of the Al₂O₃-coated LiNi_1/3Co_1/3Mn_1/3O₂ compared to uncoated LiNi_1/3Co_1/3Mn_1/3O₂.     

聚氯乙烯弹性体气候老化性能研究

将聚氯乙烯(PVC)弹性体试样进行户外曝晒试验,对试样老化前后的外观、力学性能、扫描电镜、红外光谱等试验结果进行分析比较,考察了光、热、氧对PVC弹性体气候老化性能的影响。研究结果表明:曝晒6个月后PVC的外观暗淡但有韧性,出现少量裂纹,分布也不均匀;拉伸强度逐渐增加,而断裂伸长率逐渐下降,16个月时下降到73.26%。导致断裂伸长率下降和拉伸强度逐渐增加的原因是DOP增塑剂的慢慢挥发。PVC样品经过16个月的曝晒后的红外光谱显示:波峰1620cm-1的出现说明有C=C存在,波峰969cm-1的消失说明高分子中的CH2断裂,这些都是分子老化所造成的。最后通过数学建模应用软件计算16个月后的断裂伸长率,预测可知:PVC弹性体在户外暴露30个月后就失去使用价值。     

一种基于随机GA的提高BP网络泛化能力的方法

LM-BP网络对其初始权值和阈值敏感,泛化能力不强,针对该缺点,采用遗传算法（GA）对其初始权阈值进行优化,在一定程度上能提高LM-BP网络的泛化能力。为进一步扩展GA初始种群的覆盖范围,进一步提高LM—BP网络的泛化能力,采用多次随机产生初始种群多次优化的方法。以伦河孝感段氟化物含量为实例,建立随机GA的LM—BP网络模型,对原始数据进行拟合及测试,结果表明该方法基本能100％拟合,测试误差不超过2．3％。经过对比实验,证明了该方法的有效性。     

银型抗菌沸石的合成

沸石类抗菌材料是一种无机多功能材料，具有耐酸，耐碱，过滤除污，吸附除臭以及长效广泛的杀菌和抑菌效果，主要介绍液相，固相离子交换法将具有抗菌性能的银离子与沸石合成为抗菌沸石，用正交法确定两种方法的较佳条件，并进行比较，用红外光谱对沸石原样与抗菌沸石进行比较分析，同时对合成的抗菌沸石进行了抗菌性能测试。     

气—液传质设备浮阀复合塔板的应用

介绍气～液传质设备中浮阀复合塔板的应用情况，采用浮阀复合塔板可在尽可能不降低板效率的同时提高塔器的生产能力。     

腐殖(植)酸与食品源头安全--腐殖(植)酸是构筑食品源头安全的最佳选择

腐殖（植）酸（Humic Acid，以下简称HA）是天然有机化合物。在农业应用上十分广泛，主要有土壤改良剂、肥料、农药、植物生长剂、兽药、饲料添加剂、水产养殖剂等产品。从狭义的角度说，食品生产源头指土、水、肥、药、种等主要生产环节的硬条件。HA与食品生产源头诸要素之问关系密切。HA与土壤：土壤是种植业依赖的生命基础；HA是土壤有机质中的重要组成部分，也是最活跃的部分。HA与水：水是生命之源；HA在水生体系中普遍存在，是转运大多数生命必需物质甚至毒性物质的一种非常好的工具。HA与肥料：肥料是植物的粮食；HA在改良肥料、增加肥效、提高肥料利用率、协调各种营养等方面具有非常重要的作用。HA与农药：农药是植物的保护伞；HA具有提高农药药效、降低农药毒性、保护农业环境的基本条件。HA与种苗：种苗不好，作物不保；HA是孵化种苗的“保育剂”。除土、水、肥、药、种外，HA因其具有生理活性特征，而与种植业相关的诸多因素均有良好的协同作用。在此基础上，由HA开发的农用产品，涉足改土、活水、制肥、制药、种苗处理及其他衍生制剂等6大类产品，足以构筑起立体农业的防护体系，也是构筑食品源头安全的最佳选择。     

Activated carbon fiber cloths as electrodes for high performance electric double layer capacitors

Activated carbon fiber cloth (ACFC) electrodes with high double layer capacitance and good rate capability were prepared from polyacrylonitrile (PAN) fabrics by optimizing the carbonization temperature prior to CO₂ activation. The carbonization temperature has a marked effect on both the pore structure and the electrochemical performances of the ACFCs. Moderate carbonization at 600 °C results in higher specific surface area and larger pore size, and hence higher capacitance and better rate capability. The specific capacitance of the ACFCs in 6 mol L⁻¹ KOH aqueous solution can be as high as 208 F g⁻¹. It remains 129 F g⁻¹ as the current density increases to 10 000 mA g⁻¹.     

银系无机抗菌剂的研究进展

本文综述了银系无机抗菌剂的抗菌机理，类型，制备工艺和应用现状及其抗菌性能评价的方法，探讨了银系无机抗菌剂的发展趋势。     

Necrodols: Anti-insectan terpenes from defensive secretion of carrion beetle (Necrodes surinamensis)

Two compounds recently isolated from the defensive gland ofNecrodes surinamensis, -and -necrodol, first representatives of a new category of monoterpenes (the necrodanes), are shown to be repellent to ants and other insects and irritating to cockroaches and flies. The compounds doubtless play a defensive role inNecrodes. The possible long-range applied significance of research on insect repellents is discussed.Paper No. 80 of the seriesDefense Mechanisms of Arthropods. Paper No. 79 is T. Eisner et al., Experientia 42:204–207 (1986).