Influence of cerium content on the structure and magnetic behavior of Co-Fe-Cu-Ce permanent magnets

As part of a continuing program to understand and optimize the magnetic behavior of Co-Fe-Cu-Ce permanent magnet alloys, we have made studies on the alloy system Co3.5Fe0.5CuCexwith x in the range 0.8 to 1.2. An alloy of x = 1 had previously been studied in detail and found to have good permanent magnet properties. In the present work, it was found that when x > 1, the coercive force was increased while both the Curie temperature and saturation magnetization were decreased. However when x < 1, the coercive force tends to decrease while the Curie temperature and saturation magnetization increase. The increase in coercive force with increase in cerium content can be accounted for largely by the decrease in saturation magnetization. These results are in accord with a domain wall pinning mechanism. Scanning electron microscopy studies have shown that a major second phase in the low cerium alloys is low in copper as compared with the matrix. On the contrary, the copper content of the second phase in the high cerium alloys is larger than that in the matrix.     

A new methodology to evaluate locking protocols

The average lock range (ALR) is proposed as an evaluation factor for measuring the strengths and weaknesses of locking-based concurrency control methods, for both structural and nonstructural locking. The methodology provides a simple and general way to analyze the performance of any locking method, and requires no queueing model. Based on the concept of the ALR, two popular locking protocols, the 2PL protocol and the tree protocol, are analyzed and a simulation is done to validate the correctness of the ALR model     

The orientation and temperature dependence of the yield stress of Ni3 (Al,Nb) single crystals

The flow stress of Ni₃(Al, Nb) single crystals has been measured as a function of orientation in the temperature range 77 to 910 K. While the increasing flow stress behavior is similar to that observed in other Ni₃Al-based alloys, the absolute value of the stress was found to be much higher. Also, the effect of orientation changes was to produce much greater changes in the temperature at which the peak flow stress occurs than has been previously observed. The operative slip systems were analyzed by two surface slip trace analysis. Primary octahedral slip was found to be predominant at temperatures below the peak stress temperature, while primary cube slip is prevalent above the peak temperature. The anomalous increase in the flow stress of Ni₃(Al, Nb) with increasing temperature is generally consistent with the thermally activated cross-slip of a/2<110> dislocations from {111} planes onto {100} planes. The cross-slip is shown to be aided not only be the resolved shear stress on the {100} cross-slip plane but also by the stress tending to constrict the a/<112> Shockley partial dislocations on the primary glide plane.     

非对称横电磁波传输室的工程设计

本文利用非对称横电磁波传输室(ATEM Cell)的特性分析公式,给出了一套ATEMCell的工程设计方法。该方法借助计算机,实现了对ATEM Cell的三大参数(特性阻抗、截止频率和横向场分布)的优化设计。该方法的特点是,计算准确度高,方便工程应用。文中提供的数据图表为工程人员提供了更便捷的设计途径。     

Atomically sharp silicon and metal field emitters

A method is described for forming atomically sharp silicon tips of less than 10-15° half-angle by utilizing a known oxidation inhibition at regions of high curvature; equally sharp silicon wedges are now made in a similar fashion. The sharp silicon tips serve as the starting point for forming sharp tips of W, β-W and gold. Field emission data from silicon emitters are compared with Fowler-Nordheim modelling and emission as a function of emitter-anode distance is described     

National Asian American Psychology Training Conference.

Describes a conference convened to explore problems and issues in training psychologists to serve Asian Americans and their communities and to provide a setting for administrators, faculty, practitioners, and students to share perspectives on the mental health needs of Asian Americans. Among the outcomes were recommendations concerned with appropriate models and approaches of psychology for Asian Americans and appropriate training of psychologists for Asian-American communities. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Socioeconomic factors in relation to fetal growth in white infants

Over 1,200 white mothers who were delivered consecutively at this medical center were classified in four different socioeconomic classes according to family affluence and occupations of the heat of the household. The frequency of low-birth-weight infants was highest in the lowest socioeconomic class. The high incidence of LBW infants in the lowest socioeconiomic group was not affected by any significant increase in number of mothers with medical problems or medical complications of pregnancy; it was dependent on the large number of mothers who were involved in four specific practices, largely of their own choosing, including low-weight gains, cigarette smoking, use of certain drugs during pregnancy, and refraining from all prenatal care. Mothers in the four socioeconomic classes who were not involved with these four specific practices (smoking, etc.) and whose pregnancies were free of medical problems and complications had uniformly low incidences of LBW infants and the mean birth weights of their infants were uniformly high and not significantly different. Unfavorable outcome of pregnancy with respect to fetal growth in this study appeared to depend less directly on socioeconomic circumstances than on the four specific maternal practices listed above.