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21.
Sven Beyer Christian Jacobi Daniel Kröning Dirk Leinenbach Wolfgang J. Paul 《International Journal on Software Tools for Technology Transfer (STTT)》2006,8(4-5):411-430
In the verified architecture microprocessor (VAMP) project we have designed, functionally verified, and synthesized a processor
with full DLX instruction set, delayed branch, Tomasulo scheduler, maskable nested precise interrupts, pipelined fully IEEE
compatible dual precision floating point unit with variable latency, and separate instruction and data caches. The verification
has been carried out in the theorem proving system PVS. The processor has been implemented on a Xilinx FPGA.
A shorter version of this article with the title “Instantiating uninterpreted functional units and memory system: functional
verification of the VAMP” appeared in [8]. The work reported here was done while all the authors were with Saarland University. 相似文献
22.
H. Ji D. Chopp J. E. Dolbow 《International journal for numerical methods in engineering》2002,54(8):1209-1233
A hybrid numerical method for modelling the evolution of sharp phase interfaces on fixed grids is presented. We focus attention on two‐dimensional solidification problems, where the temperature field evolves according to classical heat conduction in two subdomains separated by a moving freezing front. The enrichment strategies of the eXtended Finite Element Method (X‐FEM) are employed to represent the jump in the temperature gradient that governs the velocity of the phase boundary. A new approach with the X‐FEM is suggested for this class of problems whereby the partition of unity is constructed with C1(Ω) polynomials and enriched with a C0(Ω) function. This approach leads to jumps in temperature gradient occurring only at the phase boundary, and is shown to significantly improve estimates for the front velocity. Temporal derivatives of the temperature field in the vicinity of the phase front are obtained with a projection that employs discontinuous enrichment. In conjunction with a finer finite difference grid, the Level Set method is used to represent the evolution of the phase interface. An iterative procedure is adopted to satisfy the constraints on the temperature field on the phase boundary. The robustness and utility of the method is demonstrated with several benchmark problems of phase transformation. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
23.
In the late eighties and up to the beginning of nineties computation of turbulent flows is mostly dominated by RANS (Reynolds
Averaged Navier-Stokes Simulation) type modelling. During the last few years URANS (Unsteady RANS) and LES (Large Eddy Simulation)
type of approaches have been attempted with some success. Yet, there have been many difficulties when LES is applied to practical
engineering problems and to high Reynolds number flows as energy dissipating eddies become really small and mesh resolution
required for a reasonably resolved LES approaches that of DNS (Direct Numerical Simulation). An alternative solution suggested
was to combine RANS and LES, which in general referred to as Hybrid LES. There have been many proposals for combining RANS
and LES in different ways. In this article, some of the issues involved in performing hybrid LES reported in the recent literature
is briefly reviewed. 相似文献
24.
Influence of Ni Interlayers on the Mechanical Properties of Ti6Al4V/(WC-Co) Friction Welds 总被引:2,自引:0,他引:2
M. Shamanian M. Salehi A. Saatchi T. H. North 《Materials and Manufacturing Processes》2003,18(4):581-598
Ni interlayers were introduced prior to dissimilar friction welding of Ti6Al4V base material to three cemented carbide substrates. The fracture strength of Ti6Al4V/(WC-6 wt% Co) welds were poor and were markedly improved when 20-µm thick Ni interlayers were introduced prior to dissimilar friction welding. These results were only produced when the (WC-6 wt% Co) cermet was electroplated prior to friction welding. When the Ti6Al4V alloy was electroplated prior to friction welding, fractured WC particles and cracking were observed in the (WC-Co) carbide substrate. The fracture strengths of Ti6Al4V/(WC-11 wt% Co) and Ti6Al4V/(WC-24 wt% Co) welds were not improved when 20-µm thick Ni interlayers were introduced prior to friction welding. During mechanical testing, the Ni layer retained at the dissimilar joint interface created a region of weakness. 相似文献
25.
Takuma Suzuki Hang-Ju Ko Agus Setiawan Jung-Jin Kim Koh Saitoh Masami Terauchi Takafumi Yao 《Materials Science in Semiconductor Processing》2003,6(5-6):519-521
We report the successful growth of Ga-polar GaN epilayers on O-polar ZnO templates pre-deposited on c-sapphire. Prior to GaN growth, NH3 is exposed onto the ZnO template. The polarity of the GaN layers is confirmed by etching of the surface and by conversion beam electron diffraction (CBED), while the O-polar ZnO is confirmed by CBED. It is suggested that the NH3 pre-exposure helps form a Zn3N2 layer, which possesses inversion symmetry and inverts the crystal from anion polar to cation polar. 相似文献
26.
针对TPS/TDC30 0 0系统串口通讯方式、机理进行了一般性的介绍 ,对规划与应用中常见的的问题 ,根据实际工程应用经验提出了解决方案。 相似文献
27.
O.V. TretyakV.A. Skryshevsky V.A. VikulovYu.V. Boyko V.M. Zinchuk 《Thin solid films》2003,445(1):144-150
The character of electronic states in porous silicon (PS)-Si, Pd-PS interfaces, and/or PS bulk at the formation of the metal-PS-silicon heterostructure was studied. The energy parameters were estimated using the deep-level transient spectroscopy and capacitance-voltage characteristics at the accounting of the voltage drop distribution along the structure. The analytical expression for voltage drop distribution along dielectric layer, porous layer and space charge region in silicon was obtained by solving the equation for continuity of the electrostatic induction vector. The electronic states studied were shown to manifest the quasi-continuous sub-band in the energy gap if the porous layer was 30-nm thick. Their density increased, as the energy position was being transformed to a deeper energy level of Ev+0.81 eV at the PS layer growing to 90 nm wide. 相似文献
28.
网络虚接口对特殊数据包的处理起着很大的作用。文章介绍了网络虚接口的概念,在对传统的网络接口比较分析的基础上,设计和实现了一个基于量Linux的用于对发送数据包的内容进行特殊处理的网络虚接口。 相似文献
29.
30.
地震复合波地质属性的研究方法 总被引:1,自引:0,他引:1
何隆运 《石油地球物理勘探》1992,27(5):681-687,692
在地震资料解释中,地震复合波的地质属性问题一直没有得到很好地解决。本文针对松辽盆地砂泥岩薄互层的地质特点,提出了用波形合成追踪法研究地震复合波地质属性的方法。该方法在地震复合波正演合成过程中有五个可以识别的特征界面,其中 C 界面是地震复合波形成的主导界面;C 至 D 界面间的地层为形成地震复合波的主要地层。因此,找准 C 界面深度是建立地震复合波与钻孔地层间有机联系的关键,对地震地质层位准确标定和利用地震剖面复合波波形信息进行岩性预测极为重要。文中的应用实例表明,用该方法在松辽盆地较好地建立了地震信息与地质信息间的对应关系,解决了一些疑难地质问题,取得了较好的勘探效果。 相似文献