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991.
992.
M. V. Venkatesan N. Murugan Shiju Sam Shaju K. Albert 《Transactions of the Indian Institute of Metals》2014,67(3):375-383
This paper discusses the influence of Flux Cored Arc Welding Process parameters such as welding current, travel speed, voltage on bead profile, metallurgical and mechanical properties of welds of 2 mm thick 409M ferritic stainless steel sheets. The study reveals that, grain coarsening, volume fraction of martensite, hardness of heat affected zone and % of delta ferrite in ER 309 weld metal increases with increase in heat input. However, the results show that variation of heat input does not make any significant effect on tensile strength of the joint. Hence, welding parameters that provide uniform bead profile for the weld are recommended for fabrication. 相似文献
993.
We show that local dynamics require exponential time for two sampling problems motivated by statistical physics: independent
sets on the triangular lattice (the hard-core lattice gas model) and weighted even orientations of the two-dimensional Cartesian
lattice (the 8-vertex model). For each problem, there is a parameter λ known as the fugacity, such that local Markov chains are expected to be fast when λ is small and slow when λ is large. Unfortunately, establishing slow mixing for these models has been a challenge, as standard contour arguments typically
used to show that a chain has small conductance do not seem to apply. We modify this approach by introducing the notion of
fat contours that can have nontrivial area, and use these to establish slow mixing of local chains defined for these models. 相似文献
994.
A mathematical stack model of a molten carbonate fuel cell was numerically solved for temperature, gas dynamic pressure, and cell performance. The model assumed a steady state, constant load operation for a co‐flow stack with an external reformer. The numerical computation was done for a two‐dimensional domain with a real size of cell specifications. The effect of two stack operation variables, gas utilization and system pressure, was thoroughly analysed. The computation results were demonstrated in the form of flow fields, temperature contours, axial profiles, and plots of characteristic values. Our analysis began with an underlying fact that a high cathode gas flow is necessary for stack temperature control. The analysis result verified the effect of stack cooling by the cathode gas, and showed various aspects of stack operation and performance under pressurization. The pressurization effect is most significant in a moderate pressure range of 1–5 atm. The gas dynamic pressure, as it inevitably increases at a high gas flow rate, is regulated by pressurization. All the pressurization effects can generally be represented using a dimensionless parameter, named a pressurization factor. The relation between gas dynamic pressure and total system pressure was clarified from the related flow equations. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
995.
Sam Jenkins 《电子与电脑》2008,(6)
无线产业虽然持续地演变着,但当前则是处于一个史无前例的转变状态.新兴的4G空中界面-WiMAX、LTE、UMB、802.20、WiBRO、新一代PHS等一所有都拥有共同的特点:其均根据正交频分多任务存取(OFDMA)、均利用MIMO(多输入多输出)、以及均拥有"平坦架构(flattenedarchitecture),同时,也都是以IP为基础(网络通信协议). 相似文献
996.
Performance improvement of geographically distributed cosimulationby hierarchically grouped messages
Sungjoo Yoo Kiyoung Choi Dong Sam Ha 《Very Large Scale Integration (VLSI) Systems, IEEE Transactions on》2000,8(5):492-502
To improve the performance of geographically distributed cosimulation, we propose a concept called hierarchically grouped message. The concept improves cosimulation performance, preserving the cosimulation accuracy, by hierarchically grouping messages transferred between simulators in a short period of simulated time into a single physical message, thereby reducing the number of physical messages. Applying the concept to hybrid and optimistic cosimulation, we can reduce the number of rollbacks as well as the communication overhead accompanying the message transfer. Experimental results show the efficiency of the proposed method for practical examples in an internationally distributed cosimulation environment 相似文献
997.
Il Jin Park Sam Jin Kim Chul Sung Kim 《Journal of Superconductivity and Novel Magnetism》2011,24(1-2):689-692
The crystallographic and magneto caloric effects of La0.7Ca0.3Mn0.99 57Fe0.01O3 powders were studied by using X-ray diffraction, vibrating sample magnetometer, and M?ssbauer spectroscopy. To investigate the effect of sintering conditions on LCMO, the samples were sintered in air and evacuated sealed quartz tube. The calculated magnetic entropy change in the magnetic fields of 1.5?T for the samples which sintered in air and evacuated sealed quartz tube are 1.6?J/kg?K and 3.2?J/kg?K, respectively. The temperatures of the maximum slope in dM/dT for the samples which sintered in air and evacuated sealed quartz tube are 242?K and 262?K, respectively. For the explanation of the M?ssbauer line broadening, we applied the presence the fluctuating magnetic field, which jumps between the values of hyperfine field, +H and ?H, along the z-axis with a frequency?f. We calculated anisotropy energy from M?ssbauer relaxation analysis. 相似文献
998.
999.
In this article, we further extend the Queue-formation structure (or Q-structure) in 3D spaces with additional features including: (i) specifying orientation information, (ii) a mechanism for forming sub-formations before the convergence into the final formation, and (iii) adapting the communication structure when communications are limited. The virtual Bobber-agents are used to guide each vehicle toward the appropriate queue, by acting as intermediate targets. In addition, virtual constellation-agents bias the motion of each vehicle to within a user-defined cone to the front of the vehicle so that abrupt direction changes are avoided as far as possible. The proposed scheme relies mainly on simple behaviors between embodied and virtual agents and is computationally inexpensive method. Extensive simulations show the effectiveness of the proposed method. 相似文献
1000.
Kong Myeong Bae Jae Min Lee Ki Beom Kwon Ki-Ho Han Nam Yeol Kwon Jeong Sam Han Jong Soo Ko 《Journal of Mechanical Science and Technology》2014,28(4):1449-1454
A high-shock 2000 g accelerometer with suspended piezoresistive sensing bridges has been designed, fabricated, and tested. Structural size of the accelerometer has been obtained through an optimal design process. Four resistors are electrically connected to form a Wheatstone bridge circuit. A sensitivity of 25.5 μV/g has been measured from the fabricated accelerometer with a nonlinearity of 0.2% in an acceleration range within 2000 g. The real-time response of the fabricated accelerometers accurately follows the reference accelerometer. The newly fabricated accelerometer has survived an over-shock condition of 4667 g. 相似文献