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51.
Khoruzhaya Vera G. Martsenyuk Petr S. Meleshevich Konstantin A. Velikanova Tamara Ya. 《Powder Metallurgy and Metal Ceramics》2002,41(5-6):278-283
The reaction of components of the Si — Al — O — N — Ti system in its elements Si 3N4 — AlN, TiN — AlN, and Al 2O 3 — AlN was investigated by differential thermal and x-ray diffraction analysis. It was established that upon hot pressing mixtures of Si3N 4 and AlN (up to 1950°C) free silicon is formed by the decomposition of Si 3N4, which reacts with oxygen present as an impurity to form SiO. When TiN reacts with AlN a phase with the spinel structure (Al23O 27N 5), which can form only in the presence of excess oxygen, appears in addition to the initial components. Spinel is also produced by the reaction of Al 2O3 with AlN. In this case a eutectic between Al 23O27N5 and Al2O3 is observed. 相似文献
52.
Soft errors are an important challenge in contemporary microprocessors. Particle hits on the components of a processor are expected to create an increasing number of transient errors with each new microprocessor generation. In this paper we propose simple mechanisms that effectively reduce the vulnerability to soft errors In a processor. Our designs are generally motivated by the fact that many of the produced and consumed values in the processors are narrow and their upper order bits are meaningless. Soft errors canted by any particle strike to these higher order bits can be avoided by simply identifying these narrow values. Alternatively soft errors can be detected or corrected on the narrow values by replicating the vulnerable portion of the value inside the storage space provided for the upper order bits of these operands. We offer a variety of schemes that make use of narrow values and analyze their efficiency in reducing soft error vulnerability of level-1 data cache of the processor 相似文献
53.
Interactive distance learning (IDL) is an evolving paradigm of instruction and learning that attempts to overcome both distance and time constraints found in traditional classroom learning. The electronic classrooms at two sites of the University of Oslo and two further sites in Norway overcome separations in space by exchanging digital audio, video, and whiteboard information via the Norwegian academic ATM-based network Supernett II. The electronic classrooms are used since 1993 for teaching graduate level courses. This paper presents measurements and analysis results of transport, application, and user level Quality-of-Service (QoS) of the electronic classrooms. We describe our general experiences with this system for synchronous IDL. The lessons learned represent the motivation for the ongoing extension to support asynchronous IDL by a multimedia database system (MMDBS) to manage all data used and generated in the electronic classrooms. 相似文献
54.
Seasonal affective disorder (SAD) is characterized by annual major depressive episodes. It occurs most commonly in young women during autumn and winter with full remission during the following spring. The patient's mood is a combination of depression and anxiety accompanied by fatigue, loss of libido, and a reduction of socialization. Most of these patients complain of atypical vegetative symptoms (e.g. hypersomnia, carbohydrate craving, and weight gain). Hypotheses on the underlying mechanisms of these behavioural disorders indicate that environmental variables, e.g. climate, latitude, light, and changes in neurotransmitter function that occur naturally with the seasons, may be important. Phototherapy is being used increasingly for the treatment of SAD. The antidepressant response is contingent on the exposure of the patients' eyes to light. The biological basis of the diverse psychological and biological changes in SAD and the underlying mechanism of action of phototherapy are still unclear and require further study. 相似文献
55.
56.
The glucose transporter protein syndrome (GTPS) is caused by defective transport of glucose across the blood-brain barrier via the glucose transporter GLUT1, resulting in hypoglycorrhachia, infantile seizures, and developmental delay. Recent reports indicated that GLUT1 is a multifunctional transporter. We investigated the transport of vitamin C in its oxidized form (dehydroascorbic acid) via GLUT1 into erythrocytes of 2 patients with GTPS. In both patients, uptake of oxidized vitamin C was 61% of the mothers' values. Our findings are consistent with recent observations that vitamin C is transported in its oxidized form via GLUT1. We speculate that impaired transport of this substrate and perhaps other substrates in GTPS might contribute to the pathophysiology of this condition. 相似文献
57.
Tharinger Deborah J.; Lambert Nadine M.; Bricklin Patricia M.; Feshbach Norma; Johnson Neal F.; Oakland Thomas D.; Paster Vera S.; Sanchez William 《Canadian Metallurgical Quarterly》1996,27(1):24
National, state, and local education reform agendas have been on a fast track for more than a decade. Although some psychologists have been active in promoting psychology and psychological services in education reform initiatives, knowledge about their efforts is fragmented. In order to educate psychologists about education reform, this article highlights the impetus for the recent education reform movement, briefly reviews the latest waves of education reform, and discusses the development of the National Education Goals. Then, an argument is made for the integration of education, health, and social reform initiatives; state-level education reform principles and initiatives are highlighted, illustrated by the systemic education reform mandate in Kentucky. Next, progress toward the development and implementation of an APA-sponsored response to the National Education Goals is discussed. Finally, objectives and roles for psychologists in advancing education reform are presented, and guidelines for the education and training of future psychologists are introduced. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
58.
MARKTRAN II is an interactive FORTRAN IV program that computes Markov transition probabilities for two-dimensional patterns. The pattern is represented by a series of discrete states at each point on a rectangular grid composed of square cells. Transition probabilities in eight directions are computed. MARKTRAN II is useful for numerically describing the fabric of patterns that possess any degree of anisotropy. Geological applications include analysis of rock fabrics, outcrop patterns of geological maps, and variations in ore grade expressed as discrete states. 相似文献
59.
Willy Jankowski 《国际钢铁研究》1977,48(12):629-632
Definition von Eigenspannungen. Verfahren zum Nachweis und zur Messung von Eigenspannungen. Vorstellung eines neuen Meßverfahrens zur Bestimmung der Höhenverteilung von Eigenspannungen. Mechanische und spannungsoptische Modellversuche. Anwendung des Meßverfahrens auf Schweißeigenspannungen. 相似文献
60.