一矩阵方程组的反射解     

常海霞  王卿文 《上海大学学报(英文版)》2007,11(4):355-358

We derive necessary and sufficient conditions for the existence and an expression of the （anti）reflexive solution with respect to the nontrivial generalized reflection matrix P to the system of complex matrix equations AX = B and XC = D. The explicit solutions of the approximation problem min x∈Ф ｜｜X - E｜｜F was given, where E is a given complex matrix and Ф is the set of all reflexive （or antireflexive） solutions of the system mentioned above, and ｜｜·｜｜ is the Frobenius norm. Furthermore, it was pointed that some results in a recent paper are special cases of this paper.  相似文献   

Rational scale of urban rail transit network based on system dynamics     

LIU You-jun  JING Xiao  GUO Qian-wen 《重庆大学学报(英文版)》2011,10(1):26-34

Optimization design and experimental research for space intelligent structurecapacity, high efficiency and low pollution. Estimating URT network scale is the key to ensure the scientificity and feasibility of its construction. The existing studies on rational scale of URT network have not dealt with the interaction of supply and demand. This paper describes the establishment of a system dynamics model of rational URT network scale determination, considering the interaction between URT construction and city social economic development as well as the dynamic equilibrium of capital supply and traffic demand, and the verification of the model validity by applying it to the case of Wuhan City’s URT construction.  相似文献   

计算流体力学软件在汽车气动问题研究中的应用     

张楠 《重庆职业技术学院学报》2011,20(2):125-127

汽车在行驶过程中受到空气的作用力,会对汽车运动产生影响。汽车气动特性的研究是汽车设计研发的重要内容,随着计算机技术与数值计算方法的发展,计算流体力学（CFD）在汽车气动特性的研究中得到日益广泛的应用,特别是各类计算流体力学商业软件使其参与工程设计成为可能。文章在介绍计算流体力学的基础上,结合实例对计算流体力学软件在汽车气动问题研究中的应用进行了探究。  相似文献   

绪论课的地位作用与讲授策略   总被引：1，自引：0，他引：1  

杨志安 《唐山学院学报》2011,24(2):92-93,105

论述了绪论课的地位、作用与讲授策略,指出绪论课的教学目的。强调绪论课就是要回答为什么学、学什么、怎么学三个基本问题,概述了机电系统动力学绪论课的教学实践成果。  相似文献   

一对称矩阵方程组解的研究     

江静  马燕  蓝海波 《山东教育学院学报》2011,26(5):109-111

给出了四元数体上一对称矩阵方程组有斜埃尔米特解的充分必要条件,并得到了此方程组的斜埃尔米特解的一般表达式。应用主要结果讨论了四元数矩阵A和B矩阵有共同的斜埃尔米特广义逆的充要条件及斜埃尔米特广义逆的表示。  相似文献   

论网络媒体和传统媒体的角色差异——郭德刚事件舆论传播解读     

许鑫 《惠州学院学报》2011,31(2)

郭德刚事件由公众人物与媒体之间的司法纠纷演变成一场有关公共道德和社会风气的大讨论.传统媒体在事件中大都持批评郭德刚的立场,网络舆论则经历了由"倒郭"到"挺郭"的转变,造成传统媒体和网民立场差异的根源是公众对传统媒体舆论监督的越位及公权力介入公共讨论的不满,以及网络舆论的"反沉默螺旋"效应.郭德刚事件凸显了权力与公众冲突时传统媒体与网络媒体的角色差异.  相似文献   

辽宁装备制造业转型升级与智能化建设的系统动力学研究     

王层层 《科技管理研究》2020,40(7):190-199

在相关文献、辽宁装备制造业发展现状基础上,应用系统动力学构建转型升级与智能化建设模型,在验证模型有效性的基础上进行实证模拟分析。仿真结果显示,要使智能化产品产值增长率持续增长,应将新技术引进和产学研合作外部投入要素、政府和市场等外部支撑投入要素维持在一定平衡状态下,增加技术投入比率和高技术人才内部投入要素,最终提高自主创新能力,逐步提升辽宁装备制造业转型升级与智能化进程。  相似文献   

Exploring CO2 mitigation pathway of local industries using a regional-based system dynamics model     

《International Journal of Information Management》2020

Low-carbon development based on low energy consumption, low pollution and low emissions has become an important strategic choice for worldwide governments to achieve sustainable development. In order to support smart government in decision making, information systems have been developed to monitor and predict CO₂ emissions. Most of the existing studies investigate CO₂ emission amounts, identify influencing factors of CO₂ emission and discuss potential suggestions to mitigate CO₂ emission for different industries. They often focus on CO₂ emission research of industries in a region or country, while the integration of carbon flow in the neighboring regions is not well studied. Therefore, this paper proposes a system dynamics model to explore an optimal carbon emission reduction path of a regional industry by integrating regional differences, i.e., industrial comparative advantages, technology advantages and the inter-regional context between the neighboring regions. In the case study, we use a key industry in a typical industrial region of Western China, the cement industry in Chongqing, as a scenario to simulate the CO₂ emission, possible energy demand and cement production of the cement industry in this region for recent years. Simulation results show that by leveraging the regional differences, especially the collaboration of the industrial chain and production capacity among regions, the cement industry in Chongqing can achieve the low-carbon target. In addition, through the analysis and discussions about the features of our model and Chongqing’s cement industry, it reflects that our model using regional differences is applicable to industries with a common demand market at the regional level such as energy, chemical and steel industries.  相似文献   

Dynamics and manipulation of ferroelectric domain walls in bismuth ferrite thin films     

Shuyu Xiao  Yaming Jin  Xiaomei Lu  Sang-Wook Cheong  Jiangyu Li  Yang Li  Fengzhen Huang  Jinsong Zhu 《国家科学评论(英文版)》2020,7(2):278

Ferroelectric domain walls differ from domains not only in their crystalline and discrete symmetry, but also in their electronic, magnetic, and mechanical properties. Although domain walls provide a degree of freedom to regulate the physical properties at the nanoscale, the relatively lower controllability prevents their practical applications in nano-devices. In this work, with the advantages of 3D domain configuration detection based on piezoresponse force microscopy, we find that the mobility of three types of domain walls (tail-to-tail, head-to-tail, head-to-head) in (001) BiFeO₃ films varies with the applied electrical field. Under low voltages, head-to-tail domain walls are more mobile than other domain walls, while, under high voltages, tail-to-tail domain walls become rather active and possess relatively long average lengths. This is due to the high nucleation energy and relatively low growth energy for charged domain walls. Finally, we demonstrate the manipulation of domain walls through successive electric writings, resulting in well-aligned conduction paths as designed, paving the way for their application in advanced spintronic, memory and communication nano-devices.  相似文献   

Diagnosis of CO2 dynamics and fluxes in global coastal oceans     

Zhimian Cao  Wei Yang  Yangyang Zhao  Xianghui Guo  Zhiqiang Yin  Chuanjun Du  Huade Zhao  Minhan Dai 《国家科学评论(英文版)》2020,7(4):786

Global coastal oceans as a whole represent an important carbon sink but, due to high spatial–temporal variability, a mechanistic conceptualization of the coastal carbon cycle is still under development, hindering the modelling and inclusion of coastal carbon in Earth System Models. Although temperature is considered an important control of sea surface pCO₂, we show that the latitudinal distribution of global coastal surface pCO₂ does not match that of temperature, and its inter-seasonal changes are substantially regulated by non-thermal factors such as water mass mixing and net primary production. These processes operate in both ocean-dominated and river-dominated margins, with carbon and nutrients sourced from the open ocean and land, respectively. These can be conceptualized by a semi-analytical framework that assesses the consumption of dissolved inorganic carbon relative to nutrients, to determine how a coastal system is a CO₂ source or sink. The framework also finds utility in accounting for additional nutrients in organic forms and testing hypotheses such as using Redfield stoichiometry, and is therefore an essential step toward comprehensively understanding and modelling the role of the coastal ocean in the global carbon cycle.  相似文献