新型无机轻质绝热材料——彭胀玻化微珠及其应用

膨胀玻化微珠是一种新型的无机轻质骨料及绝热材料,它是利用含结晶水的酸性玻璃质火山岩(如:珍珠岩、黑耀岩及松脂岩等)经粉碎、脱水(结晶水)、汽化膨胀、熔融玻化等工艺生产而成。其颗粒呈不规则球状,其内部为多孔的空腔结构,而外表面封闭、光滑,具有质轻、绝热、防火、耐高温、耐老化、吸     

模糊结构和机械系统的能度可靠性分析方法

模糊系统的可靠性评估是工程中倍受关注的重要问题。结构系统的可靠性与结构的失效模式有关。模糊结构系统失效的可能度取决于失效可能度最大的最危险失效模式。因此，最危险失效模式的识别及对应极限状态方程的建立是模糊结构系统可靠性分析的关键问题。本文基于模糊结构的能度可靠性理论，建立模糊结构和机械系统的能度可靠性分析模型。所提出的模糊结构体系失效模式的枚举准则，可在只需枚举出少量主失效模式的条件下，不漏掉最危险失效模式。算例分析表明文中方法是有效和可行的。     

甲基丙烯酸三氟乙酯和丙烯酸甲酯乳液共聚：乳胶粒子大小及形貌研究

成功地合成了一系列甲基丙烯酸三氟乙酯/丙烯酸甲酯共聚物乳液,固含量约为30%（wt）。研究了乳化剂SDS/OP-10比例、引发剂KPS用量、单体投料比例对乳胶粒子大小及形貌的影响。实验结果表明：阴离子乳化剂十二烷基硫酸钠（SDS）的用量对乳胶粒子的粒径影响较大,粒径从59 nm至100 nm,粒度分布（PDI）变化不大;引发剂用量和单体比例对乳胶粒子影响较小,其中单体比例对乳胶粒子的大小几乎没有影响。     

用PS-SnCl_4-CH_3COC_2H_5固载引发剂引发异丁基乙烯基醚聚合及其动力学

用PS-SnCl_4-CH_3COC_2H_5固载引发剂引发了异丁基乙烯基醚(IBVE)的聚合反应,研究了诸因素对IBVE聚合反应的影响。结果表明,在大气环境和常温下,IBVE本体聚合的动力学方程为R_p=K[I]~(2/3)。对不同的助剂,R_p的递减顺序为CH_2ClCH_2Cl,CCl_4,CHCl_3。聚合反应初期和中期的反应活化能分别为-26.48kJ/mol和45.63kJ/mol。聚合物的(?)_n随反应时间或单体转化率的增加而增大。在适宜的温度下,当固载引发剂用量较少,助剂用量较大时,该反应为易控制的匀速反应。     

数学课堂教学中实施素质教育探讨

对于从事中专数学教学工作的教师来讲 ,课堂教学是我们从事教学活动的主要手段和途径 ,如何在课堂教学中实施素质教育是我们广大数学教师的迫切任务。在现代的社会中 ,数学的内容、思想、方法和语言已经广泛地应用到自然科学及现代科学技术中 ,数学教学在实施素质教育中占有重要的地位。要想在课堂教学中有效的合理的实施素质教育不仅要组织好课堂教学还要明确素质教育的内容及特征。1　什么是素质 ?素质 ,包含的两层意思 :指事物本来的性质和素养。“事物本来质”,对人而言 ,指的是道德质 ;素养就是各种能力。素质教育作为一种教育思想、教…     

Longitudinal and transverse magnetoelectric voltage coefficients of magnetostrictive/piezoelectric laminate composite: theory

This paper presents a novel, long-type of magnetostrictive and piezoelectric laminate composite design in which the layers are, respectively, magnetized/poled along their length axes, and a theory for modeling its behavior. Using piezoelectric and magnetostrictive constitutive equations, and an equation of motion, a magneto-elasto-electric bieffect equivalent circuit is developed. The circuit is used to predict the longitudinal and transverse magnetoelectric (ME) voltage coefficients of our Terfenol-D/Pb(Zr/sub 1-x/Ti/sub x/)O/sub 3/ laminate design. It is found that the longitudinal ME voltage coefficient is significantly higher (/spl sim/5x) than the transverse one, and that our new laminate design has significantly higher ME voltage coefficients under small applied direct current (DC) magnetic bias fields than designs reported previously by other groups. Experimental values were found to be coincidental with predicted ones.     

Magnetoelectric coupling, efficiency, and voltage gain effect in piezoelectric-piezomagnetic laminate composites

The magnetoelectric (ME) effect of piezoelectric-magnetostrictive laminate composites, which is a product tensor, has been studied. Based on piezoelectric and piezomagnetic constituent equations, the longitudinal-mode vibration and equivalent circuits have been derived. The effective magnetoelectric coupling coefficient, voltage-gain, and output efficiency have been determined. Our results show: (i) that there is an extreme high voltage gain effect of >260 under resonance drive: the induced ME voltage is much higher than the input voltage to the coils for magnetic excitation; (ii) that there is an optimum ratio of the piezoelectric to piezomagnetic layer thicknesses, which results in maximum effective magnetoelectric coupling; and (iii) that the maximum output efficiency of magnetoelectric laminate at resonance drive is ∼98%, if eddy currents are neglected. This high ME voltage gain effect offers potential for power transformer applications.     

国内压电陶瓷声马达的研究现状

综述了国内部分压电陶瓷声马达的研究发展情况,指出其产品开发所面临的困难,并提出今后需要进步解决的一些关键问题。