期刊文献+
共找到9篇文章
< 1 >
每页显示 20 50 100
Effect of Initial Load on the MechanicalProperties of Concrete Beam Strengthenedwith Extraneous Prestress
1
作者 殷惠光 付修兵 赵启林 《Journal of China University of Mining and Technology》 2004年第2期179-183,共5页
In order to study the effect of initial load on the mechanical properties of concrete beam strengthened with extraneous prestress, contrastive experiments were conducted on three reinforced concrete beams with differe... In order to study the effect of initial load on the mechanical properties of concrete beam strengthened with extraneous prestress, contrastive experiments were conducted on three reinforced concrete beams with different initial loads. The results indicate that the mechanical properties of the three beams are different. The cracking of reinforced concrete due to the initial loads badly weakens the rigidity of the reinforced concrete structure. Under the same increment in load, the greater the initial load is, the smaller the rigidity of the reinforced concrete beams becomes. The calculation methods of deflection and split of reinforced concrete beam are proposed. 展开更多
关键词 extraneous PRESTRESS strengthening CONCRETE EXPERIMENT
下载PDF
Extraneous fixed points of Euler iteration and corresponding Sullivan's basin 被引量:2
2
作者 王兴华 韩丹夫 《Science China Mathematics》 SCIE 2001年第3期292-298,共8页
The phenomenon of “numerical extraneous roots” of Euler'siteration has been found. By systematic searching, some polynomials and the corresponding initial values are given, which make the fixed points of Euler&#... The phenomenon of “numerical extraneous roots” of Euler'siteration has been found. By systematic searching, some polynomials and the corresponding initial values are given, which make the fixed points of Euler's iteration not the roots of the polynomials. For those repelling extraneous fixed points, the adjoint dynamical types of Sullivan's basins are also studied. Finally, the fractal pictures are produced. 展开更多
关键词 Euler iteration extraneous fixed point numerical extraneous roots Sullivan’s basin fractal pictures.
原文传递
Discrimination between extraneous nitrogen input and interior nitrogen release in lakes 被引量:2
3
作者 XIAO Huayun LIU Congqiang 《Science China Earth Sciences》 SCIE EI CAS 2004年第9期813-821,共9页
In this study the authors determined the nitrogen isotopes of nitrate and the carbon and nitrogen contents of water samples from the Hongfeng Lake and inflowing streams, and, on this basis, discriminated the extraneou... In this study the authors determined the nitrogen isotopes of nitrate and the carbon and nitrogen contents of water samples from the Hongfeng Lake and inflowing streams, and, on this basis, discriminated the extraneous nitrogen input and the interior nitrogen release (organic matter decomposition) in the lake. The results showed that the amount of extraneous nitrogen input into the Hongfeng Lake increases and the interior nitrogen release from the lake is intensified in winter and spring. Nitrogen mixing is relatively obvious at the catchments between the lake inlet and inflowing streams, while organic matter decomposition (nitrification) is most intense in the middle and lower reaches of the lake. In winter and spring the organic matter decomposition takes place mainly at the middle level of the water column in the middle and lower reaches of the lake, which has a bearing on the abundance of degraded organic matter at this water level. This part of degraded organic matter contains a considerable proportion of hydrogenous nitrogen in the lake. 展开更多
关键词 extraneous NITROGEN input INTERIOR NITROGEN release Hongfeng Lake.
原文传递
Three kinds of extraneous factors in Dixon resultants
4
作者 ZHAO ShiZhong FU HongGuang 《Science China Mathematics》 SCIE 2009年第1期160-172,共13页
Dixon resultant is a basic elimination method which has been used widely in the high technology fields of automatic control, robotics, etc. But how to remove extraneous factors in Dixon resultants has been a very diff... Dixon resultant is a basic elimination method which has been used widely in the high technology fields of automatic control, robotics, etc. But how to remove extraneous factors in Dixon resultants has been a very difficult problem. In this paper, we discover some extraneous factors by expressing the Dixon resultant in a linear combination of original polynomial system. Furthermore, it has been proved that the factors mentioned above include three parts which come from Dixon derived polynomials, Dixon matrix and the resulting resultant expression by substituting Dixon derived polynomials respectively. 展开更多
关键词 Dixon resultant Dixon matrix extraneous factors 00A06 13A50 13P99 68W30
原文传递
The Velocity Synchronizing Control on the Electro-Hydraulic Load Simulator 被引量:39
5
作者 焦宗夏 高俊霞 +1 位作者 华清 王少萍 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2004年第1期39-46,共8页
This paper builds up an accurate nonlinear mathematical model of anelectro-hydraulic force/ torque servo control system, and provides a thorough theoretical analysison the feedforward compensation for extraneous force... This paper builds up an accurate nonlinear mathematical model of anelectro-hydraulic force/ torque servo control system, and provides a thorough theoretical analysison the feedforward compensation for extraneous force/torque, whose limitation is analyzed andrevealed. The nonlinear factors and the servo valve dynamics have much influence on the systemcharacteristics. Subsequently a velocity syn-chronizing-compensation method by using the controlsignal of the control actuator is proposed, which can reduce the lagging effects for the betterperformance. For the reason of similarity between the model of control actuator and that of the loadsimulator, the proposed method performs well against the influence of nonlinear factors. Thesimulations and the experiments confirm that this control scheme results in a quick response,robustness, and excellent ability against disturbance. 展开更多
关键词 load simulator synchronizing control extraneous force/torque
下载PDF
在Internet环境下的MRP-Ⅱ 被引量:2
6
作者 李丹 顾海波 +1 位作者 陈荣秋 郭宏伟 《科研管理》 CSSCI 北大核心 2001年第1期106-111,共6页
本文基于传统MRP -Ⅱ系统革新的探索 ,论述了MRP -Ⅱ在Internet的环境下的新模式 ,并提出了一个应用新模式 ,并提出了一个应用模型。
关键词 MRP-Ⅱ INTERNET/INTRANET Extrane 虚拟企业
下载PDF
PERFORMANCE COMPARISON OF A LINEARLY COMBINED ORDERED-STATISTIC DETECTORS UNDER POSTDETECTION INTEGRATION AND NONHOMOGENEOUS SITUATIONS 被引量:2
7
作者 Mohamed Bakry El_Mashade 《Journal of Electronics(China)》 2006年第5期698-707,共10页
Several Constant False Alarm Rate (CFAR) architectures, where radar systems often employ them to automatically adapt the detection threshold to the local background noise or clutter power in an attempt to maintain a... Several Constant False Alarm Rate (CFAR) architectures, where radar systems often employ them to automatically adapt the detection threshold to the local background noise or clutter power in an attempt to maintain an approximately constant rate of false alarm, have been recently proposed to estimate the unknown noise power level. Since the Ordered-Statistics (OS) based algorithm has some advantages over the Cell-Averaging (CA) technique, we are concerned here with this type of CFAR detectors. The Linearly Combined Ordered-Statistic (LCOS) processor, which sets threshold by processing a weighted ordered range samples within finite moving window, may actually perform somewhat better than the conventional OS detector. Our objective in this paper is to analyze the LCOS processor along with the conventional OS scheme for the case where the radar receiver incorporates a postdetection integrator amongst its contents and where the operating environments contain a number of secondary interfering targets along with the primary target of concern and the two target types fluctuate in accordance with the Swerling Ⅱ fluctuation model and to compare their performances under various operating conditions. 展开更多
关键词 Constant False Alarm Rate (CFAR) detectors Clutter edges extraneous targets Postdetection integration Ordered-statistic algorithm
下载PDF
RESEARCH ON CONTROL METHOD OF HYDRAULIC TORQUE SIMULATOR 被引量:1
8
作者 Wang Shaoping Jiao Zongxia Hua Qing Institute of Automation Science and Electronic Enginearing, Beijing University of Aeronautics and Astronautics 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2001年第1期36-39,共4页
An effective controller and compensator is designed by using the system identification and constant structure theory to realize the effective control. The experimental results indicate the extraneous torque can be dec... An effective controller and compensator is designed by using the system identification and constant structure theory to realize the effective control. The experimental results indicate the extraneous torque can be decreased by 90% and the characteristics can be improved greatly by means of this kind of method. 展开更多
关键词 Hydraulic torque simulator extraneous torque Compensating network
下载PDF
Where Is the Site of the “Oxygen Burst” Located During Light Induction in Dark-Adapted Leaves? A Study Using Photoacoustic Techniques 被引量:3
9
作者 Da-YongFAN Rong-FuGAO 《Journal of Integrative Plant Biology》 SCIE CAS CSCD 2005年第5期567-578,共12页
: The “oxygen burst” phenomenon that appeared during the light-induction period of intact leaves could be monitored using a photoacoustic technique high time resolution. The relationship between oxygen bursts and da... : The “oxygen burst” phenomenon that appeared during the light-induction period of intact leaves could be monitored using a photoacoustic technique high time resolution. The relationship between oxygen bursts and dark-adapted time, far-red light pretreatment, photothermal signal, and chlorophyll a (Chl a) fluorescence kinetics were investigated in the present study. Using extraneous inhibitors or cofactors of electron transport, a modified vacuum-infiltration method was undertaken to locate directly the site at which oxygen bursts of intact leaves occurred. We found that the photothermal signal showed little evidence of oscillation during the light-induction period. The oxygen burst was resolved into two components if dark-adapted time lasted longer than 20 min. Methyl viologen (MV) or far-red light could not eliminate the first component, whereas formate-Na (pH 7.0,20 μmol/L) eliminated the first component but had no effect on the second one. Furthermore, the photochemical quenching, the electron transport rate of Chl a fluorescence, and the first component of the oxygen bursts approached lowest values simultaneously. This evidence indicates that the site at which the first component of oxygen bursts occurred was located between photo-system (PS)I and PSII (i.e. the PQ pool). The formate-Na experiment also showed a linkage between the first component and the S state of oxygen evolution at the donor side of PSII. Furthermore, elimination of the second component by far-red light and absorption of the second component by MV indicated that the site at which the second component of oxygen bursts may be located at the acceptor side of PSII. 展开更多
关键词 chlorophyll a (Chl a) fluorescence extraneous inhibitors and cofactors of electron transport oxygen burst of intact leaves photoacoustic technique
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部