无铅阴极的相变致电子发射研究

研究了最新无铅阴极钛酸铋钠(Na1 2Bi1.2TiO3，NBT)基铁电陶瓷的电子发射性能和电子发射的机理。采用常规陶瓷工艺制备了发射阴极样品，并在阴极上施加高达15kV的激励脉冲，获得了20A／cm^2的最大发射电流密度。在施加激励电压的同时观察到3个发射电流脉冲峰值，该现象不同于其他的阴极。通过测试NBT基铁电陶瓷的相变性能，修正了得到公认的快极化反转致电子发射理论，提出相变致电子发射理论公式，合理解释了该新型无铅NBT基阴极的电子发射3个峰现象，说明了电子发射不仅可以由快极化反转产生，也可以由相变导致的极化变化产生。     

The science of prevention: A conceptual framework and some directions for a national research program.

A conceptual framework for studying the prevention of human dysfunction is offered. On the basis of recent advances in research on the development of psychological disorders and methods of preventive intervention, generalizations about the relation of risk and protective factors to disorder are put forward, along with a set of principles for what may be identified as the science of prevention. Emerging themes from the study of human devlopment, in general, need to be incorporated in the models for explaining and preventing serious problems of human adaptation. The article concludes with a set of recommendations for a national prevention research agenda. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Note of caution on the factor analysis of the MMPI.

Although the dangers associated with factoring test scales containing overlapping items (items used on more than 1 scale) have been pointed out by Guilford (1952), factor studies of scales embodying item overlap continue. The present study explores the possibility that the neurotic triad and the psychotic triad or tetrad factors found in 4 studies derive from the existence of a methodological artifact associated with item overlap. To test this possibility, MMPI interscale common-element correlations (produced solely by item overlap) were factor analyzed. 2 of 3 factors extracted are highly similar to neurotic triad and psychotic triad or tetrad factors found for 4 samples. These 2 factors do not appear in a factor analysis of truncated (overlap items removed) MMPI scale scores. Since the overlap factors are based solely on the scale intercorrelations due to overlap items, these results appear to support Guilford's warning and open to question the legitimacy of these MMPI factors. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Means-ends thinking, adjustment, and social class among elementary-school-aged children.

Presented 6 stories to 74 normal and 34 emotionally disturbed middle- and lower-class 10-12 yr. olds to test Ss' cognitive capacity in solving simulated real-life problems. This capacity was measured by means-ends thinking, defined as an ability to construct a story plot that reflects planning, awareness of potential obstacles, and recognition of time necessary to reach a stated goal. Irrespective of social class and intellectual functioning, disturbed youngsters in special schools expressed both fewer elements of means-ends thinking and stories more limited to pragmatic, impulsive, and physically aggressive means than did normal Ss in regular schools. Implications are that training in this area early in a child's life could supplement a preventive mental health program. (PsycINFO Database Record (c) 2010 APA, all rights reserved)