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941.
The predicting capability of various parameters related to solids by performing their high pressure electronic band structures
is discussed in detail. The studies on ground state crystal structure, magnetic structure and magnetic phase transitions under
pressures,s-d electron transitions, bulk modulus, Debye temperature, elastic constants, insulator to metal transitions and the phenomenon
of pressure induced superconductivity will be discussed with examples. Especially the method of calculating the Debye temperature
for a large number of ternary charlcopyrite systems using their recently evaluated band structure will be presented. The limitations
of the band theory when used with the local density approximation with respect to the determination of band gaps and magnetic
properties will also be discussed. 相似文献
942.
论现代农业对传统农耕文化的继承和发展 总被引:2,自引:0,他引:2
科技技术是现代农业发展的动力,而传统农耕文化则是现代农业的基础与源头。本文阐明了现代农业必须继承和发展传统农耕文化所总结的几千年来农业发展的规律,才能得到健康快速发展。 相似文献
943.
介绍了基于键合图理论的机构动力学统一方法。给出了一般机构的键合图模型,所推导出的机构动力学统一方程,可分别用于机构动力学正、逆问题,具有规则化的特点,特别适合于计算机自动生成。用实例说明所述方法的有效性。 相似文献
944.
How does cognitive therapy prevent relapse in residual depression? Evidence from a controlled trial.
Teasdale John D.; Scott Jan; Moore Richard G.; Hayhurst Hazel; Pope Marie; Paykel Eugene S. 《Canadian Metallurgical Quarterly》2001,69(3):347
This study examined the cognitive mediation of relapse prevention by cognitive therapy (CT) in a trial of 158 patients with residual depression. Scores based on agreement with item content of 5 questionnaires of depression-related cognition provided no evidence for cognitive mediation. A measure of the form of response to those questionnaires, the number of times patients used extreme response categories ("totally agree" and "totally disagree"), showed significant and substantial prediction of relapse, differential response to CT, and conformity to mediational criteria. CT reduced relapse through reductions in absolutist, dichotomous thinking style. CT may prevent relapse by training patients to change the way that they process depression-related material rather than by changing belief in depressive thought content. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
945.
This paper treats the upper-bound approach to the problem of rigid-plastic deformation in case where the configuration of
the deformation zone is previously unknown. The plane strain forward extrusion process with the so-called dead metal zone
is analysed by assuming a simple velocity field. The calculations are carried out for the material with or without strain
hardening or strain rate sensitivity and for various reduction ratios. The numerical results show that the region of the dead
metal zone becomes smaller with the increase in the reduction ratio. The calculated punch forces agree with the experimental
ones fairly well. Furthermore, it is found that the dead metal zone becomes larger with increasing the strain hardening as
well as the strain rate sensitivity of the material. 相似文献
946.
Fretting is defined as a small oscillatory displacement between two contacting bodies. The interface is damaged by debris generation and its ejection from the contact area. The application of hard coatings is an established solution to protect against fretting wear. For this study a TiN hard coating manufactured by a PVD method was selected, and tested against a smooth polycrystalline alumina ball. A fretting test programme was carried out at a frequency of 5 Hz, 100 N normal load, 100 μm displacement amplitude and at five values of relative humidity: 10, 30, 50, 70 and 90% at a temperature of 296 K. The intensity of the wear process is shown to be significantly dependent on the environmental conditions. A dissipated energy approach was employed in this study to quantify the wear rates of the hard coating. The approach gives stable prediction of wear kinetics under constant medium relative humidity. An increase of relative humidity is shown to promote the formation of hydrated structures at the interface and modify the third body rheology. This phenomenon was characterized by the evolution of wear kinetics associated with a significant variation of the corresponding energy wear coefficient. Hence, a ‘composite’ wear law, integrating the energy wear coefficient as a function of relative humidity, is introduced. It permits a prediction of wear under variable relative humidity conditions from 10 to 90% within a single fretting test. The stability of this approach is demonstrated by comparing various variable relative humidity sequences. 相似文献
947.
Stanton Annette L.; Lobel Marci; Sears Sharon; DeLuca Robyn Stein 《Canadian Metallurgical Quarterly》2002,70(3):751
Emphasizing research published in the past decade, this article presents a summary and evaluation of psychosocial investigations of women's reproductive health, with a focus on selected aspects of menstruation, pregnancy and birth, infertility, and menopause. In some areas, studies have focused on negative physical and psychological concomitants of these health issues. However, research reveals substantial individual variability, with most women adapting well to reproductive health changes. Although methodological and conceptual shortcomings have limited firm conclusions, research has advanced our understanding of the multivariate biological, psychological, and social influences on women's reproductive health and associated outcomes. Understanding and promoting women's reproductive health across the lifespan requires biopsychosocial approaches to research. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
948.
As performance goals aim to both procure acknowledgment of one's abilities and to avoid revealing a lack of one's abilities, the authors hypothesized that students hold specific performance goals for different addressees and that there are specific correlational patterns with other motivational constructs. They analyzed a data set of 2,675 pupils (1,248 boys and 1,426 girls) attending Grades 8 and 9 (mean age=15.0, SD=0.97). The students completed a questionnaire consisting of 12 items measuring performance approach goals and 12 items measuring performance avoidance goals. In each subset, 4 groups of addressees were differentiated: parents, teachers, peers, and the acting individual him/herself. Additionally, several external criteria were measured. The authors concurrently tested theory-driven, structural equation models. Incorporating all 24 items, the best-fitting model was a multitrait-multimethod model, which posited 2 factors for approach and avoidance goals and 4 addressee factors. While performance goals addressing parents showed relationships to maladaptive motivational and learning patterns, performance goals addressing classmates and self showed relationships to adaptive motivational and learning patterns. The relationships between performance goals addressing teachers and external criteria were rather weak and unsystematic. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
949.
采用系统法选择高效离心式冷水机组 总被引:3,自引:0,他引:3
离心式冷水机组能效越高,价格越高,主张选用高能效制冷机,但也反对盲目追求高能效,介绍了一种结合中国当前经济发展水平,。采用系统法选用高效离心式制冷机的方法与实例,供广大空调设计者与业主参考。 相似文献
950.
Abstract In this work, a robust and accurate strategy for simulating counterflow moving bed dryers is presented. A complete pseudo-transient phenomenological model for the process has been developed and the variable time is used as a continuation parameter. The desired solution is the final steady-state reached by the model. The code DASSL is used to perform the integration of the differential algebraic equation system and consistent initialization is achieved via a direct technique. The computational effort is surprisingly small comparing to those reported in the literature. Reasonable concordance between simulated and experimental results has been observed even though the mathematical model contains no adjustable parameters. Convergence problems have not been observed for all tested operating conditions, including those pointed by other authors as particularly difficult. The mathematical tool built is capable of making accurate predictions about the behavior of the equipment in affordable computing time and hence this constitutes an invaluable tool to study counterflow moving bed drying. 相似文献