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91.
92.
高压水清除氧化皮技术 总被引:2,自引:0,他引:2
本文系统地介绍了联邦德国Werner and Pfteiderer公司用高压水清除轧件及锻件表面氧化皮的新技术,包括高压水清除氧化皮的机理,水耗量及压力计算、喷嘴的设计、液压系统及轧制钢板和锻件表面氧化皮的高压水清理装置 相似文献
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A recently proposed pipelined multithreading (PMT) technique exhibits wide applicability in parallelizing general sequential programs on multi-core processors. However, significant inter-core communication overhead limits PMT performance and prevents its commercial utilization. A simple and effective clustered pipelined multithreading (CPMT) approach is presented to accelerate sequential programs on commodity multi-core processors. This CPMT technique adopts a clustered communication mechanism that can yield very low average communication overhead by eliminating false sharing as well as reducing communication operation and transit delays in the software-only approach. A single-producer/single-consumer concurrent lock-free clusteredQueue algorithm based on a two-level queue structure is also proposed. The accuracy of CPMT is theoretically demonstrated. The performances of the algorithm and CPMT are evaluated on a commodity AMD Phenom four-core processor. The number of enqueue and dequeue times of the algorithm are 20.8 and 23 cycles given an appropriate parameter, respectively. The speedup of CPMT ranges from 13.1% to 119.8% for typical loops extracted from the SPEC CPU 2000 benchmark suite. 相似文献
95.
杀虫植物的研究新进展及应用发展前景 总被引:13,自引:3,他引:13
介绍了近几年杀虫植物研究的新进展,主要包括楝科、卫矛科、豆科、菊科、胡椒科、百部科、瑞香科等科杀虫植物的作用方式和部分植物的有效成分与作用机制及杀虫植物的应用概况,并分析了其应用发展前景。 相似文献
96.
Xi Mei Jing Wang Hong Zhang Zhi-cheng Liu Zhen-xi Zhang 《Computer methods and programs in biomedicine》2014
The ionic mechanism of change in short-term memory (STM) during acute myocardial ischemia has not been well understood. In this paper, an advanced guinea pig ventricular model developed by Luo and Rudy was used to investigate STM property of ischemic ventricular myocardium. STM response was calculated by testing the time to reach steady-state action potential duration (APD) after an abrupt shortening of basic cycling length (BCL) in the pacing protocol. Electrical restitution curves (RCs), which can simultaneously visualize multiple aspects of APD restitution and STM, were obtained from dynamic and local S1S2 restitution portrait (RP), which consist of a longer interval stimulus (S1) and a shorter interval stimulus (S2). The angle between dynamic RC and local S1S2 RC reflects the amount of STM. Our results indicated that compared with control (normal) condition, time constant of STM response in the ischemic condition decreased significantly. Meanwhile the angle which reflects STM amount is less in ischemic model than that in control model. By tracking the effect of ischemia on intracellular ion concentration and membrane currents, we declared that changes in membrane currents caused by ischemia exert subtle influences on STM; it is only the decline of intracellular calcium concentration that give rise to the most decrement of STM. 相似文献
97.
Human tracking has been a challenging task for robot in the past decades. In this paper, to realize the human following in a cluttered environment, a human tracking system based on adaptive multi-feature mean-shift (AMF-MS) under the double-layer locating mechanism (DLLM) is proposed to solve the problem of distinguishing target, occlusion, and quick turning. The DLLM, considering the course location processing and fine location processing, is designed to estimate the person’s position using the fusion of heterogeneous data. As an ID tag attached on target can be detected by RF antennas, the course locating method can track the target easily and quickly. The Bayes rule is introduced to calculate the probability where the tag exists due to the instability of RF signals. In the fine locating step, the AMF-MS is proposed because it can reduce computational load and represent target by multi-feature histogram function. Meanwhile, we combine extended Kalman filter and AMF-MS to overcome MS’s inability of occlusion. To control the robot following the target person precisely, an intelligent gear shift strategy based on fuzzy control is implemented by analyzing the robot structure. Experiments demonstrate that the proposed approach is robust to handle complex tracking conditions, and show the system has an optimum performance. 相似文献
98.
《Expert systems with applications》2014,41(16):7032-7045
This paper studies the double auction (DA) mechanism in Ma and Li (2011) for a class of exchange economies. We extend their results to more general cases where sellers and buyers each form a complex time non-homogeneous Markovian chain, as specified in Ram et al. (2009), in the communication of their private information. A numerical example is also provided. Both bubbles and crashes are observed in the example, consistent with results of our theorems. Our example and theoretical results provide new evidence that a DA mechanism, widely utilized in real exchange markets, may contribute to the excess volatility identified in Shiller (1981) and LeRoy and Porter (1981). 相似文献
99.
采用密度泛函(DFT)方法对于ZSM-5分子筛上苯与乙烯的烷基化反应机理进行研究。选取了包含酸性质子的8T原子簇模型代表ZSM-5分子筛的部分结构。采用B3LYP/6-31G(d)水平从生成能与反应活化能角度对于烷基化反应发生时可能存在的2种联合机理和一种分步机理进行了计算与比较。结果表明,联合反应机理中乙烯的质子化和C-C键的形成同时发生,而分步机理开始于乙醇盐中间体的生成,随后与苯反应生成反应产物。分步机理中乙醇盐中间体生成步骤的活化能(124.55 kJ/mol)低于联合机理的反应活化能(168.98 kJ/mol和156.06 kJ/mol),而烷基化步骤的活化能(209.35 kJ/mol)高于联合机理的反应活化能,由此可以推断ZSM-5分子筛上苯与乙烯的烷基化反应时2种机理同时发生,存在竞争关系。 相似文献
100.