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排序方式: 共有188条查询结果,搜索用时 15 毫秒
21.
Hamouda R.M. Alolah A.I. Badr M.A. Abdel-Halim M.A. 《Energy Conversion, IEEE Transaction on》1999,14(4):918-922
This paper presents a comparative study on the starting performance of three phase wound-rotor induction motors under different methods of starting. These methods are online direct starting, variable rotor resistance starting and double feed starting. In the double feed starting, the rotor winding is connected in parallel with the stator winding across the supply for a predetermined short period. By this connection, the motor produces an extremely high starting torque. For carrying out the investigations sought, a rigorous state space mathematical model has been developed and simulated. The effect of torsional dynamics has been taken into considerations 相似文献
22.
A framework for the development of an environmental management system that satisfies the requirements of the ISO 14001 standards is presented. The framework is developed for NB Power, a company producing electricity for the province of New Brunswick in Canada. A case study is carried out in a thermal power plant called Coleson Cove. An initial review of the existing environmental management programs is presented. The environmental policy is evaluated, and the environmental aspects and impacts of the plant's activities are identified and prioritized according to prespecified criteria of severity, frequency, degree of control, and existence of regulation. Environmental objectives and targets are set and recommendations are presented. 相似文献
23.
This paper addresses the analysis of a two-way semi-blind amplify-and-forward (AF) relay network, in which the relay node requires partial instantaneous channel state information (CSI) to amplify the received signals. First, we derive the expression of end-to-end signal-to-noise ratio in dual-hop transmissions over independent and not necessarily identically distributed Rayleigh fading channels. Based on the opportunistic AF selection relaying, we define bounds of some metrics such as average sum-rate and outage probability. Furthermore, we provide exact and approximate expressions for the average symbol error rate. The obtained results show that the performance of the proposed system decreases slightly while the processing complexity is reduced significantly compared to those of CSI-assisted AF relay schemes. In order to prove the exactness of the proposed analysis, a selection of numerical results is provided. 相似文献
24.
Doxorubicin is cardiotoxic and its use must be monitored carefully. Incidence of refractory cardiac failure is shown to increase once the cumulative dose exceeds 450 mg/m2. However, significant decline of ejection fraction (EF) may occur even at lower dose levels. EF was monitored using Multigated Radionuclide Angiography (MUGA) scan of all consecutive lung cancer patients, treated with Doxorubicin based regimens. Thirteen of 82 patients showed a significant (more than 15%) decline of left ventricular EF. The dose of doxorubicin producing this decline ranged between 91-180 mg/m2. Actual decline in EF ranged between 16-45%. Only 5 of 13 patients developed symptoms attributable to the cardiac disease. Doxorubicin can alter EF significantly in lung cancer patients at levels well below which are considered 'safe'. The reason for massive decline in ejection fraction in these patients has been hypothesized. 相似文献
25.
N Barbouche M Tamarelle O Richard MH Ben Hamouda J Girardie 《Canadian Metallurgical Quarterly》1994,71(1-2):33-41
Two neurohormones produced by two distinctive neurosecretory median cells (A1, B) of the protocerebum have been characterized in Locusta migratoria; on with a multiple functions one called neuroparsin and one stimulating the ovarian maturation called lom OMP. Using the specific immunoserum of these two neurohormones in Schistocerca gregaria, we could demonstrate the occurring of molecules related to the neuroparsin and lom OMP of Locusta. Through histology studies of the brain and corpora cardiaca complex, the immunoserum revealed the presence of the two types of these neurosecretory cells suggesting the occurring in Locusta as well as Schistocerca of the same cells releasing molecules immunologically apparented to neuroparsin and lom OMP. The results were confirmed by electrophoretic separation of corpora cardiaca extract under unreduced conditions followed by a transfer on immobilon membrane. 相似文献
26.
O. M. S. Alkoles E. Mahdi A. M. S. Hamouda B. B. Sahari 《Applied Composite Materials》2003,10(6):339-363
In this paper, the influence of ellipticity ratio on energy absorption capability and load-carrying capacity of woven roving wrapped composite elliptical tubes has been investigated both experimentally and numerically. A series of experiments was conducted for composite elliptical tubes with ellipticity ratios (a/b) ranging from 1 to 2. Typical failure histories of their failure mechanism are presented and discussed. The experimental data are correlated with predictions from a finite element model. Load-deformation curves and deformation histories of typical specimens are presented and discussed. For all specimens considered, classical axial collapse eigenvalues were computed. The results showed that the ellipticity ratio significantly influenced the energy absorption capabilities as well as the load-carrying capacity. Tubes with ellipticity ratios of a/b 1.25 and 2.0 displayed the highest normalised specific energy absorption capability. A reasonable agreement between the experimental and computational results was obtained for the critical crush load. 相似文献
27.
In this paper, we consider antenna/relay selection for coded cooperative networks in an effort to improve their end-to-end performance by improving the detection reliability at the relay nodes. Considering amplify-and-forward (AF) relaying, we analyze a previously proposed distributed coded cooperation scheme in conjunction with antenna/relay selection. Specifically, we derive upper bounded expressions for the bit error rate assuming M-ary phase shift keying (M-PSK) transmission. Our analytical results show that the maximum diversity order of the system is maintained for the entire range of symbol error rate of interest, unlike the case without antenna/relay selection. Several numerical and simulation results are presented to demonstrate the efficacy of the proposed scheme. 相似文献
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Edge caching is an effective feature of the next 5G network to guarantee the availability of the service content and a reduced time response for the user. However, the placement of the cache content remains an issue to fully take advantage of edge caching. In this paper, we address the proactive caching problem in Heterogeneous Cloud Radio Access Network (H‐CRAN) from a game theoretic point of view. The problem is formulated as a bargaining game where the remote radio heads (RRHs) dynamically negotiate and decide which content to cache in which RRH under energy saving and cache capacity constraints. The Pareto optimal equilibrium is proved for the cooperative game by the iterative Nash bargaining algorithm. We compare between cooperative and noncooperative proactive caching games and demonstrate how the selfishness of different players can affect the overall system performance. We also showed that our cooperative proactive caching game improves the energy consumption of 40% as compared with noncooperative game and of 68% to no‐game strategy. Moreover, the number of satisfied requests at the RRHs with the proposed cooperative proactive caching scheme is significantly increased. 相似文献