排序方式: 共有58条查询结果,搜索用时 15 毫秒
1.
Taejin Song Jaihyun Kwak B. C. De Cooman 《Metallurgical and Materials Transactions A》2012,43(1):245-262
Whereas low-carbon (<0.2 mass pct) martensitic grades can be produced easily in continuous annealing processing lines equipped
with the required cooling capacity, the thermal cycles in continuous galvanizing lines make it difficult to produce hot-dip
Zn or Zn-alloy coated high-strength martensitic grades. This is because of the tempering processes occurring during dipping
of the strip in the liquid Zn bath and, in the case of galvannealed sheet steel, the short thermal treatment required to achieve
the alloying between the Zn and the steel. These short additional thermal treatments last less than 30 seconds but severely
degrade the mechanical properties. Using a combination of internal friction, X-ray diffraction, and transmission electron
microscopy, it is shown that the ultrafine-grained lath microstructure allows for a rapid dislocation recovery and carbide
formation during the galvanizing processes. In addition, the effective dislocation pinning occurring during the galvannealing
process results in strain localization and the suppression of strain hardening. 相似文献
2.
Ri Choe Hyojin Cho Taejin Park Kwang Ryel Ryu 《Journal of Intelligent Manufacturing》2012,23(6):2179-2192
To maximize the productivity of a container terminal, the operations of various types of equipments should be optimized and synchronized in real time. However, use of optimization techniques such as mathematical programming or search-based meta-heuristics becomes difficult when given a large-scaled problem due to their high computational cost. Addressing this problem, the queue-based local scheduling and global coordination method proposed in this paper stands as a viable alternative. The method consists of the following steps. First, separate schedules are locally generated for each equipment type using a queue-based dispatching heuristic which pays attention to the queue lengths of the quay cranes (QCs) under service. Next, the schedules are executed via a simulation and a notable QC delay is identified. Based on the analysis on the causes of this delay, some compromising adjustments are made to the priorities of relevant jobs. Then, the localized scheduling followed by the adjustment is repeated until the termination condition is met. Adopting simple heuristics in the local scheduling phase, the overall process easily meets the real-time constraint, yet producing an integrated schedule with a better global perspective than the myopic heuristic-only approach. 相似文献
3.
Grigoriy Sereda Taejin Kim Aubrey Jones Hari Khatri Christopher L. Marshall H. Subramanian Ranjit T. Koodali 《Catalysis Letters》2011,141(8):1086-1096
Abstract
Catalytic performance of solid supported monovanadate catalysts toward oxidation of propane is significantly affected by the templating effect of: (1) pretreatment of the solid support with calixarene derivatives before deposition of ammonium vanadate, (2) direct deposition of vanadyl phthalocyanine as the vanadate precursor. This effect is believed to be linked to the accessibility of the active sites, and was studied in comparison with a reference mesoporous support. 相似文献4.
Analytical and experimental studies on optimal details of orthotropic steel decks for long span bridges 总被引:1,自引:1,他引:0
Orthotropic steel decks gradually come into general use in long span bridges due to various advantages such as dead weight reduction, easy quality control, and so on. On the other hand, stress concentration is often observed near the connection details, which may lead to fatigue problems and govern the design of the structure. Therefore, researches to understand the structural behaviors and examine stress distribution of details in orthotropic steel decks are required in order to develop an optimal connection detail. In this paper, optimal parameters regarding height, thickness and shear area of a cross-beam and efficiency and shapes of bulkhead plates are characterized by analytical studies and verified by experiments, so that fatigue cracks could be prevented. 相似文献
5.
Taejin Jung Kyungwhoon Cheun 《Communications Letters, IEEE》2003,7(7):329-331
New full-rate space-time block codes achieving full diversity for quadrature amplitude modulation (QAM) using an even number of transmit antennas over quasi-static Rayleigh fading channels are proposed. The proposed codes are constructed by serially concatenating unitary rotating precoders with the Alamouti code. The coding advantage of the proposed code for a codeword pair corresponding to any distinct input pair is shown to be greater than or equal to that of the ST-CR code. 相似文献
6.
Akter Nusnin Sadowski Jerzy T. Zhou Chen Zhong Jian-Qiang van Spronsen Matthijs Xu Yixin Tong Xiao Kim Taejin Tenney Samuel Head Ashley R. Stacchiola Dario J. Boscoboinik J. Anibal 《Topics in Catalysis》2019,62(12-16):1067-1075
Topics in Catalysis - The morphology of a thin palladium film deposited on bilayer Al0.35Si0.65O2/Ru(0001), previously proposed as a two-dimensional zeolite model, is investigated using a set of... 相似文献
7.
Daejun Chang Taejin Rhee Kiil Nam Kwangpil Chang Donghun Lee Samheon Jeong 《Reliability Engineering & System Safety》2008,93(12):1877-1885
This study investigated the availability and safety concerns of the conventional and prospective propulsion systems for LNG carriers:
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- dual-fuel steam turbine mechanical (DFSM) propulsion,
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- dual-fuel diesel electric (DFDE) propulsion,
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- dual-fuel gas turbine electric (DFGE) propulsion,
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- dual-fuel diesel mechanical (DFDM) propulsion, and
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- diesel mechanical propulsion with reliquefaction (SFDM+R).
8.
The MPEG‐D unified speech and audio coding (USAC) standardization process was initiated by MPEG to develop an audio codec that is able to provide consistent quality for mixed speech and music contents. The current USAC reference model structure consists of frequency domain (FD) and linear prediction domain (LPD) core modules and is controlled using a signal classifier tool. In this letter, we propose an LPD single‐mode USAC structure using an adaptive widowing‐based transform‐coded excitation module. We tested our system using official test items for all mono‐evaluation modes. The results of the experiment show that the objective and subjective performances of the proposed single‐mode USAC system are better than those of the FD/LPD dual‐mode USAC system. 相似文献
9.
Cheolwoo You Gilsang Yoon Changwoo Seo Sherlie Portugal Gihwan Park Taejin Jung Huaping Liu Intae Hwang 《Wireless Personal Communications》2011,59(4):789-806
IMT-Advanced mobile communication systems make it possible for any devices to access high-speed networks anytime and anywhere.
To meet the needs of IMT-Advanced systems, cellular systems must solve the problem of intercell interference caused by frequency
reuse. Intercell interference problems become severe when orthogonal frequency division multiplexing (OFDM) transmission,
which is a key technology for 4G communication systems, is used in a cellular system. In this paper, a zone-based intercell
interference coordination (ICIC) scheme with high flexibility and low cost is proposed, and its performance is evaluated through
multicell system-level simulations carried out according to the simplified 3GPP (3rd Generation Partnership Project) Long
Term Evolution (LTE) system parameters. In the proposed algorithm, each cell is divided into several regions based on threshold
values. Each region reuses frequencies in different ways, and the regions have different maximum transmit (TX) powers according
to the interference environment. Even though the proposed scheme can be implemented with low complexity by using only the
existing user equipment (UE) measurement, simulation results have confirmed that it provides significant improvements in geometry
distribution. 相似文献
10.