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21.
Abstract— The stability of oxide TFTs has been the main focus of this research and is probably the most crucial requirement for the successful application to flat‐panel displays. Although the high Fermi level of oxide semiconductors makes TFTs basically stable under electrical stress, the device reliability under diverse variations of electrical stress is affected by materials such as active semiconductors and gate insulators, processes for the formation of back/front channels and passivation layers, and device configurations among other things. How these factors affect the device reliability have been investigated and a review of the stability is presented. In addition, several categories of the light instability of oxide TFTs is presented and the origin is discussed.  相似文献   
22.
Degradation of device parameters over the lifetime of a system is emerging as a significant threat to system reliability. Among the aging mechanisms, wearout resulting from Negative Bias Temperature Instability (NBTI) is of particular concern in deep submicron technology generations. While there has been significant effort at the device and circuit level to model and characterize the impact of NBTI, the analysis of NBTI’s impact at the architectural level is still at its infancy. To facilitate architectural level aging analysis, a tool capable of evaluating NBTI vulnerabilities early in the design cycle has been developed that evaluates timing degradation due to NBTI. The tool includes workload-based temperature and performance degradation analysis across a variety of technologies and operating conditions, revealing a complex interplay between factors influencing NBTI timing degradation.  相似文献   
23.
中国先进研究堆自然循环两相流动不稳定性分析   总被引:1,自引:0,他引:1  
应用均相流模型对中国先进研究堆自然循环两相流动不稳定性进行数值分析计算,获得了自然循环不稳定性边界,分析了流量、压降、壁温、流体温度以及沸腾边界等参数在不稳定工况下的变化。研究结果为中国先进研究堆的安全运行和事故分析提供了重要参考。  相似文献   
24.
在航天、航空、航海领域发动机研制的过程中都有过燃烧不稳定的现象,一般通过“补救”措施来加以 解决,如加入声学抑制部件。就发动机燃气发生器发生的不稳定燃烧现象,从声学角度开展了研究,给出了产生不 稳定燃烧的归一化固有频率,进一步设计了声抑制器,并运用有限元分析软件ANSYS对其有效性进行了分析,结 果表明,该声抑制器可以很好的抑制该不稳定燃烧。  相似文献   
25.
A local level set algorithm for simulating interfacial flows described by the two‐dimensional incompressible Navier–Stokes equations is presented. The governing equations are solved using a finite‐difference discretization on a Cartesian grid and a second‐order approximate projection method. The level set transport and reinitialization equations are solved in a narrow band around the interface using an adaptive refined grid, which is reconstructed every time step and refined using a simple uniform cell‐splitting operation within the band. Instabilities at the border of the narrow band are avoided by smoothing the level set function in the outer part of the band. The influence of different PDE‐based reinitialization strategies on the accuracy of the results is investigated. The ability of the proposed method to accurately compute interfacial flows is discussed using different tests, namely the advection of a circle of fluid in two different time‐reversed vortex flows, the advection of Zalesak's rotating disk, the propagation of small‐amplitude gravity and capillary waves at the interface between two superposed viscous fluids in deep water, and a classical test of Rayleigh–Taylor instability with and without surface tension effects. The interface location error and area loss for some of the results obtained are compared with those of a recent particle level set method. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   
26.
基于Paiedoussis等同轴圆柱壳体流致不稳定性的数学模型和研究方法,分析了固支-简支端部约束条件下同轴圆柱壳体系统的流致不稳定性,结果表明:同两端固支相比,固支-简支端部边界下壳体系统的失稳临界流速更低。  相似文献   
27.
Corless and Leitmann [2] have shown that a damped simple oscillator can be destabilized by varying the spring stiffness. The present note establishes that this result is closely related to the variational approach to absolute stability theory [1,6] both in substance and in method of proof. In particular, several key ideas employed in [2] appear in the work of Brockett [1].  相似文献   
28.
张凤翔  陈贵清 《振动与冲击》2004,23(2):101-103,100
采用二维不可压缩无粘流体模型,探讨了板状结构的流致振动问题。发现板在两端简支、中点联结松动时,结构首先出现屈曲失稳,而不会发生颤振失稳。求得了具体结构参数情况下的第一阶屈曲临界流速,计算了结构参数变化对临界流速的影响。  相似文献   
29.
This paper presents experimental validation of two reference stress based methods for circumferential cracked pipes. One is the R6 method where the reference stress is defined by the plastic limit load. The other is the enhanced reference stress method, recently proposed by the authors, where the reference stress is defined by the optimised reference load. Using 38 published pipe test data, the predicted maximum instability loads according to both methods are compared with the experimental ones for pipes with circumferential through-thickness cracks and with part circumferential surface cracks. It is found that the R6 method gives conservative estimates of the maximum loads for all cases. Ratios of the experimental maximum load to the predicted load range from 0.54 to 0.98. On the other hand, the proposed method gives overall closer maximum loads than R6, compared to the experimental data. However, for part through-thickness surface cracks, the estimated loads were slightly non-conservative for four cases, and possible reasons are fully discussed.  相似文献   
30.
The present study is devoted to mathematical simulation of the instability of laser radiation. An algorithm for establishing the shape of continuous laser radiation received at the input of a measuring system is presented.  相似文献   
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