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On similitude law of sub-systems
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作者 Zach Liang George C.Lee 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2006年第1期133-142,共10页
Based on Buckingham's π-Theorem, dimensional analysis has achieved considerable success over the past near-century. Model testing has long been a powerful tool in both scientific studies and engineering applications... Based on Buckingham's π-Theorem, dimensional analysis has achieved considerable success over the past near-century. Model testing has long been a powerful tool in both scientific studies and engineering applications. However, the prototype objects are becoming more and more complicated nowadays, and many of the prototype systems can contain several sub-systems. The conventional theories on model-prototype similarity and dimensional analysis have only limited application since the π-Theorem itself does not distinguish between the original system and subsystems. This is particularly true in the field of structural dynamics, where the structure is often modeled as a multi-degree-of-freedom system. In this paper, we attempt to show that, if a system can be decoupled into several nontrivial subsystems, then, in each subsystem, the number of π-terms will be reduced and therefore simplify the model testing. On the other hand, if a system cannot be decoupled into subsystems, then using model testing with reduced π-term analysis, both experimentally and theoretically, may introduce severe errors. 展开更多
关键词 similitude law Buckingham's π-theorem model testing sub-systems
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B3G射频接收机前端设计 被引量:2
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作者 田克纯 周武中 +1 位作者 覃远年 赵峰 《电讯技术》 北大核心 2010年第11期94-99,共6页
分析了DC-OFDM零中频接收方案,采用两个相邻子载波以分路/合路的方式进行信号处理以降低硬件难度和复杂度。利用ADS软件设计了B3G射频接收机,其低噪声放大器的最低噪声系数为1.7 dB,三阶交调点为-1 dBm;下变频器在频带范围内其增益为12.... 分析了DC-OFDM零中频接收方案,采用两个相邻子载波以分路/合路的方式进行信号处理以降低硬件难度和复杂度。利用ADS软件设计了B3G射频接收机,其低噪声放大器的最低噪声系数为1.7 dB,三阶交调点为-1 dBm;下变频器在频带范围内其增益为12.5 dB,1 dB压缩点-12 dBm,三阶交调点-3 dBm。实验测试结果表明,所设计的前端满足接收机的指标要求,适合于宽带通信系统。 展开更多
关键词 B3G 宽带通信系统 零中频接收机 前端 子载波 移相器
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基于改进PSO的某前副车架自动检具参数优化 被引量:2
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作者 焦欢庆 刘波 +1 位作者 王银惠 丁爱国 《精密成形工程》 2016年第2期86-89,93,共5页
汽车前副车架生产过程中需要在线检测其几何参数,但在检测过程中,多种因素导致测量值与真实值有偏差,为了提高效率,采用自动检测系统。利用气缸将检测机构送进到结构件上的孔、轴或其他位置。当相对尺寸变化时,会带动检测机构运动,通过... 汽车前副车架生产过程中需要在线检测其几何参数,但在检测过程中,多种因素导致测量值与真实值有偏差,为了提高效率,采用自动检测系统。利用气缸将检测机构送进到结构件上的孔、轴或其他位置。当相对尺寸变化时,会带动检测机构运动,通过与检测结构连接的传感器读出相应数据,再经过信息处理方法计算出结构件的相关几何参数。测量中发现,压紧、推动、翻转等气缸的气压大小会直接影响检测的测量精度,为了提高测量精度,在不同气压下,对某型号前副车架进行了检测,得到了主要尺寸的测量值,计算了测量值与真实值的偏差;采用多项式回归分析法,得出了气压和前副车架主要尺寸的偏差的关系式;利用改进粒子群优化算法,以前副车架主要尺寸的总体偏差和为适应度函数,迭代寻优得到最佳气压值为0.4578 MPa。 展开更多
关键词 前副车架 自动检具 粒子群优化算法
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Degree of coupling and coordination of eco-economic system and the influencing factors: a case study in Yanchi County, Ningxia Hui Autonomous Region, China 被引量:13
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作者 LU Huiling ZHOU Lihua +2 位作者 CHEN Yong AN Yiwei HOU Caixia 《Journal of Arid Land》 SCIE CSCD 2017年第3期446-457,共12页
Based on the statistical data, we analyzed and evaluated the degree of coupling and coordination of the eco-economic system in Yanchi County for the period spanning from 1983 to 2014. The eco-economic system can be di... Based on the statistical data, we analyzed and evaluated the degree of coupling and coordination of the eco-economic system in Yanchi County for the period spanning from 1983 to 2014. The eco-economic system can be divided into socioeconomic and ecological sub-systems and their relationship can reveal the interaction state between the two sub-systems and help the local government to establish a coordinated development mode. An index system was constructed to assess the development of the two sub-systems before the evaluation of the degree of coupling and coordination. The principal component regression analysis was adopted to quantitatively assess the influences of natural, economic and social factors on the degree of coupling and coordination of the eco-economic system. Results showed that, from 1983 to 2014, the development trends of both sub-systems were increasing with the ecological sub-system having more fluctuations. The degree of coupling and coordination of the eco-economic system in the study area increased gradually from 1983 to 2014, but experienced five different development stages from the verge of disorder to favorable coordination. The development of the local social and economic conditions was the most important factor influencing the degree of coupling and coordination. The second most important factor was the financial support from the local government. In addition, the environment protection policies also played undeniable roles. Due to the diversity of the influence factors, the government should take comprehensive measures to promote the sustainable development of the eco-economic system. 展开更多
关键词 degree of coupling and coordination eco-economic system ecological sub-system socioeconomic sub-system YanchiCounty
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前副车架引起的WOT轰鸣问题优化、解决及质量属性平衡 被引量:2
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作者 郭志伟 张超 +3 位作者 信连彪 魏泽松 王国军 毛杰 《小型内燃机与车辆技术》 2022年第5期63-67,共5页
乘用车全油门加速(即WOT)轰鸣问题一直是整车NVH性能开发过程中的难点问题,原因在于引起WOT轰鸣问题的根源有很多,比如动力总成的标定,悬置衬套设计的合理性,车身NTF目标把控等。而前副车架作为发动机后悬置或后拉杆的安装载体,如何将... 乘用车全油门加速(即WOT)轰鸣问题一直是整车NVH性能开发过程中的难点问题,原因在于引起WOT轰鸣问题的根源有很多,比如动力总成的标定,悬置衬套设计的合理性,车身NTF目标把控等。而前副车架作为发动机后悬置或后拉杆的安装载体,如何将其合理设计是整车属性开发绕不开的话题。优秀的副车架设计需要同时满足整车多方面性能需求,在车型设计开发过程中是有较高挑战性的。通过对某车型进行NVH试验和仿真以及传递路径分析,识别出前副车架在整车上的弯曲模态频率低是在整车WOT时发动机在3 800 r/min附近有轰鸣声的主要原因。为了在新车型NVH开发过程中避免发生类似问题,从概念设计开始,应用拓扑优化、尺寸优化等优化方法,由粗到精逐步细化设计方案,最终锁定优化方案。新副车架本体约束模态频率比上一代车型副车架提升约60 Hz,且减小质量1.8 kg,同时满足了NVH性能要求和底盘轻量化指标,为整车的NVH性能达标提供了必要条件。 展开更多
关键词 WOT轰鸣 前副车架 NVH 模态优化 质量平衡
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A Symmetric Key Exchange Protocol Bsaed on Virtual S-Box 被引量:2
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作者 YIN Yifeng GAN Yong WEN Heyu LI Tianbao 《China Communications》 SCIE CSCD 2014年第A02期46-52,共7页
Based on the theory of polymorphic virtual S-box, the paper presents a symmetric key exchange protocol to solve the problem of session keys delete shared in the computational complexity temporary trading scenario. Bot... Based on the theory of polymorphic virtual S-box, the paper presents a symmetric key exchange protocol to solve the problem of session keys delete shared in the computational complexity temporary trading scenario. Both parties jointly construct a highly nonlinear SPN core algorithm. The paper the connotation of polymorphic cipher theory, making use of the method of self-compiler based expansion factor to collect random parameter sets held by each of the parties containing its own information 5-tuple private keys array Kpa[5] and Kpb[5].The more efficient polymorphism virtual S-box is constructed. The method of secret split for the public key cryptography features can be implemented by symmetry cipher system. The research results will provide a theoretical basis to solve the key exchange problems for short- term communications partner based on symmetric cryptography. 展开更多
关键词 virtual S-box the virtual iterativefunction (VIF) secrecy sub-systems
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The Applicability of the Density Rule of Pathwardhan and Kumer and the Rule Based on Linear Isopiestic Relation 被引量:1
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作者 胡玉峰 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2001年第3期319-321,共3页
The applicability of the density rule of Pathwardhan and Kumer and the rule based on the linear isopiestic relation is studied by comparison with experimental density data in the literature. Predicted and measured val... The applicability of the density rule of Pathwardhan and Kumer and the rule based on the linear isopiestic relation is studied by comparison with experimental density data in the literature. Predicted and measured values for 18 electrolyte mixtures are compared. The two rules are good for mixtures with and without common ions, including those containing associating ions. The deviations of the rule based on the linear isopiestic relation are slightly higher for the mixtures involving very strong ion complexes, but the predictions are still quite satisfactory.The density rule of Pathwardhan and Kumer is more accurate for these mixtures. However, it is not applicable for mixtures containing non-electrolytes. The rule based on the linear isopiestic relation is extended to mixtures involving non-electrolytes. The predictions for the mixtures containing both electrolytes and non-electrolytes and the non-electrolyte mixtures are accurate. All these results indicate that this rule is a widely applicable approach. 展开更多
关键词 binary density rules DENSITY apparent molar volume multicomponent system binary sub-system
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The decision-making dimension of the systems approach to management
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作者 James Kennedy Turkson 《Chinese Business Review》 2010年第2期27-33,共7页
Theoretically, a system is anything that is made up of various parts. Theses parts are known as subsystems. At every point in time, these parts should work in harmony so that objectives could be achieved successfully.... Theoretically, a system is anything that is made up of various parts. Theses parts are known as subsystems. At every point in time, these parts should work in harmony so that objectives could be achieved successfully. A system could be inanimate or animate item. Examples of inanimate systems include vehicles, households, computer and institution. Examples of animate systems are human being, animal and insect. Both inanimate and animate systems are made up of various subsystems. Such subsystems are required to co-operate, collaborate and work together so that set objectives could be achieved successfully. From practical managerial point of view, business organizations are equally systems that are made up of subsystems which may take the form of departments, sections and/or units. It is supposed to be collaborations among the managers and other members in these departments, sections and/or units so that organizational objectives could be achieved. All the managers in various departments, sections and/or units are required to work together as a team to make the system coherent and closely-knit to make disintegration impossible. Closely related to the systems approach to management is managerial decision-making. Decision-making is a very important function of every manager's job. The success and failure stories of many organizations are the result of the quality of decisions made. Many organizations have survived turbulent conditions. Others have also collapsed in spite of favourable conditions. These varying conditions are the result of the quality of decisions made by managers at positions of authority and responsibility. Therefore the systems approach to management enjoins top managers in particular to be very circumspect and cautious in certain decision-making activities. This is because, the quality of decision a manager makes can go a long way to determine the success or failure story of an organization as exemplified in the case study in this paper. 展开更多
关键词 system sub-system SYNERGY open-system closed-system MANAGEMENT decision-making
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Thermo-Dynamical Analysis on Electricity-Generation Subsystem of CAES Power Plant
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作者 Wenyi Liu Gang Xu Yongping Yang 《Journal of Power and Energy Engineering》 2014年第4期729-734,共6页
Besides pumped hydropower, Compressed Air Energy Storage (CAES) is the other solution for large energy storage capacity. It can balance fluctuations in supply and demand of electricity. CAES is essential part of smart... Besides pumped hydropower, Compressed Air Energy Storage (CAES) is the other solution for large energy storage capacity. It can balance fluctuations in supply and demand of electricity. CAES is essential part of smart power grids. Linked with the flow structure and dynamic characteristic of electricity generation subsystem and its components, a simulation model is proposed. Thermo-dynamical performance on off-design conditions have been analyzed with constant air mass flux and constant gas combustion temperature. Some simulation diagrams of curve are plotted too. The contrast of varied operation mode thermal performance is made between CAES power plant and simple gas turbine power plant. 展开更多
关键词 ELECTRICITY Generation sub-system CAES Power PLANT Thermal Performance Simulation ANALYSIS OFF-DESIGN Conditions
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ESTABLISHMENT OF THE OCEAN DYNAMIC SYSTEM WITH FOUR SUB-SYSTEMS AND THE DERIVATION OF THEIR GOVERNING EQUATION SETS 被引量:8
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作者 YUAN Ye-li QIA0 Fang-li +2 位作者 YIN Xun-qiang HAN Lei LU Ming 《Journal of Hydrodynamics》 SCIE EI CSCD 2012年第2期153-168,共16页
Based on their differences in physical characteristics and time-space scales,the ocean motions have been divided into four types in the present paper:turbulence,wave-like motion,eddy-like motion and circulation.Apply... Based on their differences in physical characteristics and time-space scales,the ocean motions have been divided into four types in the present paper:turbulence,wave-like motion,eddy-like motion and circulation.Applying the three-fold Reynolds averages to the governing equations with Boussinesq approximation,with the averages defined on the former three sub-systems,we derive the governing equation sets of the four sub-systems and refer to their sum as "the ocean dynamic system".In these equation sets,the interactions among different motions appear in two forms:the first one includes advection transport and shear instability generation of larger scale motions,and the second one is the mixing induced by smaller scale motions in the form of transport flux residue.The governing equation sets are the basis of analytical/numerical descriptions of various ocean processes. 展开更多
关键词 ocean dynamic system four sub-systems advection transport shear instability transport flux residue
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加速器驱动次临界系统发展态势分析 被引量:8
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作者 李泽霞 刘小平 +2 位作者 朱相丽 黄龙光 冷伏海 《科学观察》 2011年第3期32-43,共12页
该文聚焦加速器驱动次临界系统的相关研究,利用ISI Web of Knowledge数据库中收录的加速器驱动次临界系统相关的研究论文作为分析对象,分析了时间、主题、国家和机构等分布特征及国际合作情况,并结合定性资料的调研,表明2000年来,加速... 该文聚焦加速器驱动次临界系统的相关研究,利用ISI Web of Knowledge数据库中收录的加速器驱动次临界系统相关的研究论文作为分析对象,分析了时间、主题、国家和机构等分布特征及国际合作情况,并结合定性资料的调研,表明2000年来,加速器驱动次临界系统的相关研究日趋活跃,美国、日本、德国、法国和俄罗斯5个国家在加速器驱动次临界系统研究方面居世界前列,印度作为新兴研究国家,近年来在国际上已经产生一定的影响力。加速器的稳定性问题和加速器驱动次临界系统相关的材料化学问题及利用先进的计算工具进行预测和模拟是目前的前沿科学问题。 展开更多
关键词 加速器驱动系统 发展态势分析 前沿热点 文献计量分析
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