空洞探测问题的概率排序算法

研究了空洞探测问题 ,提出了用概率方法这一新颖思想来确定空洞在平板中的位置 .在一定概率范围内 ,求出了平板内空洞的位置 ,得到在此范围内能够确定平板内空洞位置的前提下 ,减少波源接收器的方法 .特别指出的是 ,随着给定问题所要求概率范围不同 ,所得到的结果亦不同 ,同时空洞的形状也可能不同     

有机化合物极谱催化氢波研究进展

通过50多篇文献简要地综述了有机化合物极谱催化氢波的历史进程，其过去与现在的发展状况。并由此展望了催化氢波的发展前景。     

A study on dynamic response of slopes under wave action using simulation tests

1. Introduction At present, the construction of large-scale reservoirworks has given rise to many large-scale reservoirareas, the stabilization of slopes in these reservoirdistricts will be influenced by water waves. Thecirculating hydraulic loading caused by the waveproduces a great force on the slope, and especiallyforms a vibration wave force on the boundary of water surface and the slope earth, and even breaks the water-soil interface, leading to the excess pore pressurechanging along diff…     

快速以太网和千兆以太网技术

文章根据IEEE802.3z提供的CSMA／CD模型，分析了从以太网到快速以太网、从快速以太网到千兆位以太网的演变过程，对实现千兆位以太网时CSMA/CD的MAC层所作的修改着重进行了论述。     

浅谈跨文化交际与英语教学中的文化教育

外语学习中 ,跨文化现象是一个必须予以重视的问题 ,因为不同的语言承载各自不同的文化和语言习惯。本文就跨文化现象 ,及在英语教学中所遇到的中西文化差异进行一点粗浅地探讨     

全反射与倏逝波

根据菲涅尔公式,讨论当入射角大于临界角时折射光穿透深度,相移,和反射光的位相跃变以及倏逝波的应用。     

High-Temperature Corrosion of Protective Coatings for Boiler Tubes in Thermal Power Plants

High-temperature corrosion is a serious problem for the water-wall tubes of boilers used in thermal power plants. Oxidation, sulfidation and molten salt corrosion are main corrosion ways.Thereinto, the most severe corrosion occurs in molten salt corrosion environment. Materials rich in oxides formers, such as chromium and aluminum, are needed to resist corrosion in high-temperature and corrosive environment, but processability of such bulk alloys is very limited. High velocity electric arc spraying (HVAS) technology is adopted to produce coatings with high corrosion resistance. By comparison, NiCr (Ni-45Cr-4Ti) is recommended as a promising alloy coating for the water-wall tubes, which can even resist molten salt corrosion attack. In the study of corrosion mechanism, the modern material analysis methods, such as scanning electron microscopy ( SEM ), X-ray diffractometry (XRD) and energy dispersive spectrometry (EDS), are used. It is found that the corrosion resistances of NiCr and FeCrAl coatings are much better than that of 20g steel, that the NiCr coatings have the best anti-corrosion properties, and that the NiCr coatings have slightly lower pores than FeCrAI coatings. It is testified that corrosion resistance of coatings is mainly determined by chromium content, and the microstructure of a coating is as important as the chemical composition of the material. In addition, the fracture mechanisms of coatings in the cycle of heating and cooling are put forward. The difference of the thermal physical properties between coatings and base metals results in the thermal stress inside the coatings. Consequently, the coatings spall from the base metal.     

对称正则长波方程的奇异孤立波解

利用扩展双曲函数法和齐次平衡原理,将方程的孤波解表示为双曲函数的多项式,从而将非线性对称正则长波方程的求解问题转化为非线性代数方程组的求解问题,得出了对称正则长波方程的奇异孤立波解。     

Surface-mounted bender elements for measuring horizontal shear wave velocity of soils

The bender element testing features its in-plane directivity, which allows using bender elements to measure the shear wave velocities in a wider range of in-plane configurations besides the standard tip-to-tip alignment. This paper proposed a novel bender element testing technique for measuring the horizontal shear wave velocity of soils, where the bender elements are surface- mounted and the axes of the source and receiver elements are parallel to each other. The preliminary tests performed on model ground of silica sand showed that, by properly determining the travel distance and time of the shear waves, the surface-mounted bender elements can perform as accurately as the conventional ＂tip-to-tip＂ configuration. Potentially, the present system provides a promising nondestructive tool for characterizing geomaterials and site conditions both in laboratory and in the fields.     

Na?ve Students’ Conceptual Development and Beliefs: The Need for Multiple Analyses to Determine what Contributes to Student Success in a University Introductory Physics Course

This research involved na?ve physics learners who were interested in majoring in science or engineering. In a semester-long quasi-experimental study, open-ended pretests and weekly interviews were used to analyse the progressive development of students’ conceptions relating to sound and wave motion. Semi-structured interviews were also conducted to elucidate: (1) how their conceptions developed from everyday conceptions to unclear scientific conceptions to scientific conceptions, and (2) their beliefs of physics knowledge. Despite efforts to enable these students to learn physics, the findings showed that only two out of ten students developed acceptable physics conceptions during the course that would enable them to pursue the subject to a higher level. Also, students’ conceptual development was found to be related to their cognitive understanding and to epistemological beliefs of physics. Therefore, to facilitate na?ve physics learners’ success in a general physics course, in addition to the acquisition of content knowledge, explicit emphasis needs to be placed on the nature of physics knowledge.