Hydrothermal Synthesis and Characterization of KxNa(1−x)NbO3 Powders

NaNbO₃, KNbO₃, and K _x Na_{(1− x )}NbO₃ powders were successfully prepared by the hydrothermal method. The phase of the products was identified to be orthorhombic structure by X-ray diffraction (XRD) technique, and the XRD results revealed that the x value of the K _x Na_{(1− x )}NbO₃ gradually increased with the increase in the ratio of K⁺ to Na⁺ in alkaline solution. The morphology and the microstructure were investigated by scanning electron microscopy, energy-dispersive spectroscopy, and transmission electron microscopy, and the results indicated that the ratio of K⁺ to Na⁺ in the solution had a great effect on the morphology and the size of products. Na_0.5K_0.5NbO₃ with morphotropic phase boundary composition could be synthesized when the molar ratio of K⁺ to Na⁺ was between 4:1 and 6:1 in the solution. A possible formation mechanism of the K _x Na_{(1− x )}NbO₃ crystal was also proposed based on the experimental results.     

两段法处理高浓度含砷废水的工艺研究

通过正交试验研究了用石灰、有机捕集沉淀剂(DTCR)两段法处理高浓度含砷废水的工艺条件，并与常规法比较了处理效果和处理费用。结果表明：用两段法处理后的废水可达标排放；污泥量大大减少，易脱水，含水率低，降低了后处理的难度和费用；污泥稳定，不产生二次污染。该法具有显著的社会效益和生态效益。     

界面改性PA6/TPE共混物的形态结构与性能

通过控制马来酸酐(MAH)的用量制得不同接枝率的马来酸酐接枝热塑性弹性体(TPE-g-MAH),利用其与尼龙6(PA6)在共混过程中的反应增容作用,实现了与PA6的相容共混,并研究了PA6/TPE共混物的结构与性能。结果表明,TPE-g-MAH可有效地提高PA6/TPE共混物的韧性,且随着其接枝率的增加,共混物的韧性提高;TPE-g-MAH有效地改善了PA6/TPE共混物的界面相容性,并且随着其含量的增加,相界面增容效果变好。     

CO2／酚基树脂的合成实践

本文对ＣＯ２／酚基树脂──冷芯盒工艺用树脂的合成工艺进行了一定程度的实验研究，提出了可行的几种有机合成方法，并从理论分析入手，对该类树脂的分子结构类型进行了设计和预测。     

浅谈汽车四轮定位检测与调整技术

四轮定位对汽车的正常行驶起着十分重要的作用。对汽车四轮定位参数进行检测和调整,不仅能确保汽车的正常行驶,还能延长轮胎的使用寿命,同时节省油耗。重点研究了汽车四轮定位的检测方法和调整技术。     

水蓄冷运行控制分析

随着空调蓄冷技术的不断发展,它已逐渐在节能效果、经济效益和社会效益等方面展现出强大的生命力和广阔的市场。主要探讨了自然分层蓄冷形式,该方式利用温度和密度不同的原理,通过斜温层分隔高、低温水。必须严格进行水蓄冷系统的运行控制,否则极易打破其自然分层的规律。     

核电工程项目调试工期的影响因素与优化

调试启动工作是核电工程项目进度控制中非常重要的环节,对整个工程的顺利投入运行有着重要的作用。如果调试工期过长,则会导致核电工程不能按期交付使用,从而对整个核电工程的进度造成影响。主要探讨了核电工程项目调试工期的影响因素和优化措施。     

工业喷漆的环境污染研究

化工企业对环境的影响较大,其制造的化工产品严重威胁着人们的健康。近年来,随着化工企业的规模越来越大,其带来的环境污染问题也越来越严峻。就工业喷漆对环境污染的状况和治理措施进行了分析、探究。     

Synthesis,characterization, and thermal properties of alternate copolymers containing N,N′‐bis(diphenylsilyl)tetraphenylcyclodisilazane

Hexamethyldisilazane was used as the starting material to synthesize N,N′‐bis(hydroxydiphenylsilanyl)tetraphenylcyclodisilazane (BHPTPC). By condensation polymerization of BHPTPC with α,ω‐bis(dialkylamino)dimethylsiloxane, a series of alternate copolymers containing N,N′‐bis(diphenylsilyl)tetraphenylcyclodisilazane was synthesized. GPC studies show that the highest molecular weight was obtained at a ratio of 1.005 : 1 (BHPTPC: α,ω‐bis(dimethyl amino)dimethylsiloxane). Data of DSC indicate that the temperature of glass transition (T_g) and temperature of melting point (T_m) decreased with the increasing of dimethylsiloxane segments units. Three stages of degradation were found in the thermogravimetric analysis curves. The activation energy of the copolymer (with m = 2, 3, and 7) was calculated by using Flynn–Wall–Ozawa method. The activation energy of the copolymer with m = 2, 3, and 7 at second stage is 214, 211, and 184 kJ/mol, respectively. Isothermal gravimetric analysis shows that for the same temperature and the same time, the weight loss of the alternate copolymer was greatly less than that of common polydimethylsiloxane. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 611–617, 2007