稳压二极管测试系统的研制

本文介绍了稳压二极管测试系统硬件和软件的设计思路和实现方法。该系统是一种网络化的智能测试系统,操作简单、测试迅速准确,可同时测试多个稳压二极管的参数。     

The role of atomic mobility during film growth in the structural and magnetic properties of CoCr

We have studied the morphological, crystallographic, and magnetic properties of CoCr thin films sputtered at different substrate temperatures and pressures. Conditions which produce high adatom mobility on the surface of the growing film lead to good c-axis orientation and magnetic anisotropy normal to the substrate, while low mobility leads to poor c-axis orientation and anisotropy. These results are explained in terms of van der Drift's model of the evolutionary growth of vapor-deposited films. The perpendicular coercivities of our samples depend only on the substrate temperature and we find no correlation with the film morphology or grain size.     

Brief cognitive-behavioral depression prevention program for high-risk adolescents outperforms two alternative interventions: A randomized efficacy trial.

In this depression prevention trial, 341 high-risk adolescents (mean age = 15.6 years, SD = 1.2) with elevated depressive symptoms were randomized to a brief group cognitive-behavioral (CB) intervention, group supportive-expressive intervention, bibliotherapy, or assessment-only control condition. CB participants showed significantly greater reductions in depressive symptoms than did supportive-expressive, bibliotherapy, and assessment-only participants at posttest, though only the difference compared with assessment controls was significant at 6-month follow-up. CB participants showed significantly greater improvements in social adjustment and reductions in substance use at posttest and 6-month follow-up than did participants in all 3 other conditions. Supportive-expressive and bibliotherapy participants showed greater reductions in depressive symptoms than did assessment-only controls at certain follow-up assessments but produced no effects for social adjustment and substance use. CB, supportive-expressive, and bibliotherapy participants showed a significantly lower risk for major depression onset over the 6-month follow-up than did assessment-only controls. The evidence that this brief CB intervention reduced risk for future depression onset and outperformed alternative interventions for certain ecologically important outcomes suggests that this intervention may have clinical utility. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Flow visualization during solid-liquid phase change heat transfer I. Freezing in a rectangular cavity

The results of flow visualization experiments in a rectangular test cell during the solidification of n-octadecane from above are reported. The experiments provide information on buoyancy-induced fluid motion and its effect on the shape and motion of the solid-liquid interface.     

Sleep problems of junior high school students in Taipei

The objective of this work was to study the relationship between daily sleep time and characteristics of students, e.g. grade level, gender, and academic program. A sleep habit questionnaire was designed to survey students at two junior high schools, one from northern Taipei and the other from southern Taipei. The impact of shortened duration of sleep on daily function was also evaluated. A total of 965 students and their parents were selected randomly in December 1993 for the questionnaire study. The response rate was 96.4% (930) for students and 88.6% (855) for parents. The self-reported daily sleep time of students declined, and daytime sleepiness and moodiness increased in the higher grades. The girls slept fewer hours than the boys and did not show an increase in daytime sleepiness. Those students not taking the senior high school joint entrance examination slept more hours at night and maintained more alertness in the daytime than those who were taking the examination. The more academic pressures that adolescents faced, the fewer hours they slept. Students not participating in the joint entrance examination seemed to show a healthier sleep pattern. Little sleep at night made the students feel sleepy in the daytime and tired, drowsy, moody and difficult at arising in the morning. The reason why girls slept less than boys needs further investigation.     

A fast CFAR detection space-time adaptive processing algorithm

All of the conventional CFAR detection algorithms that use space-time processing involve a time-consuming matrix-inversion operation. Based on today's technology, this computational complexity sometimes makes the full-rank solution difficult to realize. In this correspondence, a CFAR detection algorithm, which does not need a matrix inversion, is developed by an adaptation and extension of Hotelling's principal-component method studied recently by Kirsteins and Tufts (1994). Finally, the performance of the new CFAR test statistic is analyzed, and the effect of the rank reduction on performance is evaluated for an example scenario     

In situ electrokinetic enhancement for self-assembled-monolayer-based electrochemical biosensing

This study reports a multifunctional electrode approach which directly implements electrokinetic enhancement on a self-assembled-monolayer-based electrochemical sensor for point-of-care diagnostics. Using urinary tract infections as a model system, we demonstrate that electrokinetic enhancement, which involves in situ stirring and heating, can enhance the sensitivity of the strain specific 16S rRNA hybridization assay for 1 order of magnitude and accelerate the time-limiting incubation step with a 6-fold reduction in the incubation time. Since the same electrode platform is used for both electrochemical signal enhancement and electrochemical sensing, the multifunctional electrode approach provides a highly effective strategy toward fully integrated lab-on-a-chip systems for various biomedical applications.     

Magnetic thin films for information storage

In most storage technologies, the two critical components are the recording head and the recording medium; hence, improvements in storage media go hand in hand with improvements in read/write head technology. Thin films are becoming the dominant medium chosen to meet the burgeoning demand for information storage, and thin-film technology has been transferred to the read/write heads as well. Materials science plays an important role in correlating the structure, properties and processing of thin-film magnetic materials for both applications.     

Zinc finger protein GFI-1 has low oncogenic potential but cooperates strongly with pim and myc genes in T-cell lymphomagenesis

The gfi-1 gene encodes a zinc finger containing protein that is specifically expressed in T-lymphocytes and is a frequent target of proviral insertion in T-cell lymphoma provoked by infection with MoMuLV--a non acute transforming retrovirus. Expression of a gfi-1 transgene targeted to T-cells by the lck proximal promoter provokes a reduction of peripheral CD4 and CD8 positive T-cells but nevertheless weakly predisposes transgenic animals for the development of T-cell lymphoma. Forced coexpression of the serine/threonine kinase Pim-1 can partially restore normal T-cell numbers in double pim-1/gfi-1 transgenic mice. Moreover, the combinatorial expression of Pim-1 and Gfi-1 leads to accelerated development of T-cell lymphoma with a mean latency period of 114 days. A similar accelerated rate of lymphoma development was observed when lck-gfi-1 mice were crossed with mice that carry a L-myc gene targeted to be expressed at high levels in T-cells. The results show that gfi-1 can act with low activity as a dominant oncogene when overexpressed but also demonstrate that it is most efficient only in the presence of a cooperative partner protein as for example Pim-1 or L-Myc. In addition, the results suggest that Pim-1 and Gfi-1 are acting synergistically in both T-cell lymphomagenesis and T-cell development.