ZrO2对CaO-SiO2系玻璃析晶的影响

通过DSC曲线研究了不同含量的ZrO2对CaO-SiO2系玻璃析晶的影响,根据JMA方程计算动力学参数(如析晶活化能E、频率因子ν、晶化指数n)。从计算结果可以看出,随着ZrO2含量的增加,析晶活化能E减少,而频率因子ν和晶化指数n增加。当ZrO2含量为7%时,E值最小:235.58kJ/mol;n值最大:4.70。说明ZrO2在CaO-SiO2玻璃体系是有效的晶核剂。     

混炼硅橡胶的配合技术(八)

介绍了2种汽车部件（密封图、汽车挡风玻璃刮片）装配用混炼硅橡胶的配制，以及硫化过程中能与接触基材粘接的混炼硅橡胶（通过添加各种增粘剂如含乙烯烃碳酸酯基或巯基乙酸酯基化合物、烷氧基硅烷、含乙烯基硅官能基过氧化物为硫化剂）的配制。     

Factors influencing magnetic polymer microspheres prepared by dispersion polymerization

Magnetic iron oxide (Fe₃O₄) was prepared by a coprecipitation method. Core–shell composite magnetic polymer microspheres with carboxyl groups were synthesized by the dispersion polymerization of styrene and acrylic acid in the presence of magnetic oxide, and dibenzoyl peroxide was used as an initiator. The synthesized magnetic polymer microspheres were characterized with X‐ray diffraction, transmission electron microscopy, scanning electron microscopy, Fourier transform infrared spectroscopy, and so forth. The results indicated that the product was single‐phase Fe₃O₄, and its average size was about 10 nm. The configuration of the microspheres, which contained carboxyl groups, was spherical, and the average size was about 2 μm. The results of vibrating sample magnetometry tests showed that the magnetic powders produced by different surfactants had different saturation magnetizations. When poly(ethylene glycol) with a weight‐average molecular weight of 4000 was used as a surfactant, the saturation magnetization of the samples reached 69.2 emu/g. The factors that affected the shape, magnetism, size, and distribution of the microspheres were also studied. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

An SVD-based adaptive robust speech steganography using MDCT coefficient

Multimedia Tools and Applications - Speech is one of the essential ways of communication. The study of speech steganography provides great value in information security. To improve imperceptibility...     

轧制力传感器模态与瞬态仿真分析

为满足轧机振动测试的需求,对自行设计的小型轧机的轧制力传感器进行模态和瞬态仿真分析.将轧制力传感器的分析简化为对敏感元件的分析,建立仿真分析的模型,为接近轧机的实际工作受力情况,模态分析施加定载荷,而瞬态分析施加随时间变化的载荷.仿真结果表明,轧制力传感器的各阶振动频率均远高于轧机设备的固有频率,轧制力传感器的结构不会与轧机产生共振;敏感元件关键点的位移响应与轧制力函数载荷的变化基本一致,均没有激振现象的发生,说明敏感元件的设计符合轧机振动测试的要求.     

一维炉系统的测试实验

一维炉是一种研究煤的热解燃烧和结渣等方面的实验系统,可用于模拟电厂煤粉的燃烧特性。以元宝山褐煤为燃料,介绍了一维炉的结构和功能,并对系统的可靠性进行了验证,利用烟气分析仪及热重分析仪对燃烧后的尾部烟气及灰渣进行了分析测定。结果表明:尾部烟气含氧量与灰渣可燃部分剩余量均在理论计算值的误差允许范围内,说明一维炉密封良好,系统内各部分正常运行,对维炉的调试和研究具有一定的参考意义。     

层间接触状态和横向力大小对车辙贡献率的影响

车辙贡献率是反映沥青路面各结构层车辙病害程度的一个主要参数,可用于指导沥青路面的设计和施工.利用三维有限元计算软件建立三维有限元模型用于理论分析,将有限元计算结果与理论解进行对比,验证了该三维有限元模型的可靠性.采用实测的轮胎接地压力,考虑不同层间接触状态和横向力大小,结合有限元计算的数据,分析了沥青路面结构层的车辙贡献率.结果表明:在层间完全连续状态下,横向力大小的选取不能简单地选取最大垂直轮胎接地压力的一定比例,而是要根据所研究的具体情况具体分析.在对沥青路面车辙贡献率的研究中,可以忽略层间接触状态,即假定层间完全连续.     

Finite difference method for dynamic response analysis of anchorage system简

Based on some assumptions, the dynamic analysis model of anchorage system is established. The dynamic governing equation is expressed as finite difference format and programmed by using MATLAB language. Compared with theoretical method, the finite difference method has been verified to be feasible by a case study. It is found that under seismic loading, the dynamic response of anchorage system is synchronously fluctuated with the seismic vibration. The change of displacement amplitude of material points is slight, and comparatively speaking, the displacement amplitude of the outside point is a little larger than that of the inside point, which shows amplification effect of surface. While the axial force amplitude transforms considerably from the inside to the outside. It increases first and reaches the peak value in the intersection between the anchoring section and free section, then decreases slowly in the free section. When considering damping effect of anchorage system, the finite difference method can reflect the time attenuation characteristic better, and the calculating result would be safer and more reasonable than the dynamic steady-state theoretical method. What is more, the finite difference method can be applied to the dynamic response analysis of harmonic and seismic random vibration for all kinds of anchor, and hence has a broad application prospect.