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排序方式: 共有1547条查询结果,搜索用时 15 毫秒
91.
Markus Karner Andreas Gehring Stefan Holzer Mahdi Pourfath Martin Wagner Wolfgang Goes Martin Vasicek Oskar Baumgartner Christian Kernstock Klaus Schnass Gerhard Zeiler Tibor Grasser Hans Kosina Siegfried Selberherr 《Journal of Computational Electronics》2007,6(1-3):179-182
We present the Vienna Schrödinger-Poisson Solver (VSP), a multi-purpose quantum mechanical solver for investigations on nano-scaled device structures. VSP includes a quantum mechanical solver for closed as well as open boundary problems on fairly arbitrary one-dimensional cross sections within the effective mass framework. For investigations on novel gate dielectrics VSP holds models for bulk and interface trap charges, and direct and trap assisted tunneling. Hetero-structured semiconductor devices, like resonant tunneling diodes (RTD), can be treated within the closed boundary model for quick estimation of resonant energy levels. The open boundary model allows evaluation of current voltage characteristics. 相似文献
92.
A canonical form for controllable singular systems modulo restricted system equivalence is presented. The canonical form respects the decomposition of the singular system into a regular and an impulsive part. The construction is based on Popov's control canonical form and on the Jordan canonical form recently developed by Hinrichsen and Prätzel-Wolters. Continuity properties are analysed and the cellular partition of the orbit space induced by the canonical form is briefly discussed. 相似文献
93.
直接转矩控制研究现状与前景 总被引:16,自引:1,他引:15
介绍了直接转矩控制的研究现状,就几个关键问题进行了讲座,并分析了其今后的发展方向。 相似文献
94.
Frequent loss of heterozygosity on chromosome 8p in a variety of human malignancies, including head and neck cancers, has suggested the presence of a tumor suppressor gene (or genes) associated with the pathogenesis of these cancers. To test the role of genetic alterations at 8p23 in oral carcinogenesis, we studied 51 squamous cell carcinomas of the head and neck and 29 oral squamous cell carcinoma cell lines for allelic loss using 7 microsatellite markers spanning approximately 5 cM of chromosome band 8p23. Twenty-three of 51 tumors (45%) and 23 of 29 cell lines (79%) showed allelic loss at 1 or more loci. Three cell lines showed homozygous deletion of loci within a 3 cM region defined by the markers D8S1781 and D8S262. Our results suggest that a tumor suppressor gene (or genes) is located in 8p23 and is associated with the development and/or progression of oral carcinomas. 相似文献
95.
ER Seaquist 《Canadian Metallurgical Quarterly》1997,46(11):1364-1366
To determine whether arterialized venous blood obtained from a foot vein could be substituted for arterialized venous blood obtained from a hand vein during studies using the glucose clamp technique, we simultaneously measured glucose concentrations and PO2 in blood samples obtained from the heated hands and feet of five normal volunteers during the euglycemic and hyperglycemic steps of a hyperinsulinemic clamp. Plasma glucose concentrations were found to be virtually identical in arterialized venous blood drawn from the hand and the foot under both euglycemic and hyperglycemic conditions. The correlation between these values was significant (R2 = .99, P < .001). PO2 measurements in blood drawn from the heated hand or foot were not statistically different. We conclude that the glucose concentration measured in arterialized venous blood drawn from the foot is equivalent to the concentration in arterialized venous blood drawn from the hand. These observations will allow investigators to study in vivo glucose metabolism in individuals with poor venous access in the upper extremities and to use protocols that make the arms of the subject inaccessible for blood sampling during the study. 相似文献
96.
97.
Charles E. Baumgartner 《Journal of the American Ceramic Society》1990,73(3):516-520
The performance of a molten carbonate fuel cell (MCFC) is significantly eroded when fuel and oxidant gases are allowed to combine chemically as occurs with a loss of gas impermeability by the cell's electrolyte structure. This performance decline is eradicated when the cell's electrodes possess pore size distributions small enough to absorb sufficient electrolyte to act as a secondary gas barrier. Described here is a process for preparing composite MCFC NiO cathodes where the median pore size of the gas barrier region is varied from 3.2 to 0.4 μm by adjusting the starting powder's Ni/NiO ratio. When filled with liquid Li2 CO3 -38 mol% K2 CO3 at 923 K, these structures possess a gas pressure resistance of between 2.3 × 105 and 13.6 × 105 Pa, respectively. The incorporation of these composite cathodes in a MCFC can prevent the penetration of the oxidant gas into the fuel cell's interior. 相似文献
98.
Transtemporal power- and frequency-based color-coded duplex sonography of cerebral veins and sinuses
PURPOSE: To determine the ability of transtemporal power- and frequency-based transcranial color-coded duplex sonography to aid in the assessment of cerebral veins and sinuses, as well as to provide reference data for flow direction and velocity. METHODS: Using a color duplex device equipped with a 2.0/2.5-MHz sector scan, we insonated 120 healthy volunteers and three patients with cerebral venous thrombosis. RESULTS: In subjects 20 to 59 years old, deep middle cerebral veins were identified in 88%, basal veins in 97%, straight sinuses in 60%, and transverse sinuses in 42%. The corresponding values for subjects 60 to 79 years old were 53%, 86%, 23%, and 20%, respectively. Velocities were highest in transverse and straight sinuses, slower in basal veins, and slowest in deep middle cerebral veins. Flow was directed lateromedially in the deep middle cerebral vein, rostrocaudally in the basal vein and straight sinus, and mediolaterally in the transverse sinus. Two patients with straight sinus thromboses showed reversed flow direction in the basal veins, and one patient with superior sagittal sinus thrombosis showed elevated velocities in a deep middle cerebral vein. CONCLUSION: Transtemporal power- and frequency-based color-coded duplex sonography enabled imaging and velocity measurements in deep cerebral veins in subjects 20 to 59 years old, but detection of the straight and transverse sinuses was low. In older subjects, only the basal vein was regularly assessed. 相似文献
99.
100.
Gerhard Baumgartner 《Baurechtliche Bl?tter: bbl》2010,13(5):173-185
Am 1. Juli 2010 ist nach umfangreichen Vorarbeiten das Steierm?rkische Raumordnungsgesetz 2010 (StROG – LGBl 2010/49) in Kraft
getreten. Mit diesem Gesetz sollte freilich keine g?nzlich neue Rechtslage geschaffen werden, sondern es ging vor allem darum,
das bestehende Raumordnungsrecht zu konsolidieren und durch die Neuordnung zur Entlastung der Gemeinden und der Landesverwaltung
beizutragen. Als einen der wesentlichen neuen Inhalte im Bereich der ?rtlichen Raumordnung nennen die Erl?uterungen die "überarbeitung
der Freilandbestimmung". Die damit angesprochene Regelung des § 33 StROG enth?lt ua auch Vorschriften über die Zul?ssigkeit
bestimmter Bauvorhaben "im Rahmen der land- und/oder forstwirtschaftlichen Nutzung" im Freiland (§ 33 Abs 4 Z 4 StROG). In
diesem Rahmen wird – unter bestimmten Voraussetzungen – auch die Errichtung von Neu- und Zubauten für Zwecke der Privatzimmervermietung
samt dazugeh?rigen infrastrukturellen Einrichtungen für zul?ssig erkl?rt. Schon im Zuge des Gesetzgebungsprozesses waren allerdings
Zweifel laut geworden, ob diese landesgesetzliche Regelung mit den Vorgaben der Bundesverfassung vereinbar ist. 相似文献