企业家精神对企业动态核心能力影响的实证研究

以企业家精神和企业动态核心能力的测量维度研究为基础,提出二者影响关系的理论框架模型．通过对368家企业的深度访谈和问卷调查,运用结构方程模型方法对理论模型拟和度,企业家精神对企业动态核心能力影响的路径进行了实证研究．研究结果表明,企业家精神对企业核心能力存在显著、正向且直接的影响,为企业推动企业家精神的培育与企业核心能力的提升提供了相关建议．     

A Thermo-Mechanical Study of Some Epoxy Adhesives Subjected to Combined Dynamic and Static Stresses

The object of the present study was to investigate the effect of superimposed dynamic and static stresses on mechanical and thermal properties of some epoxy adhesives. It was found that combinations of shear creep and torsional oscillations, applied simultaneously to adhesive joints at temperatures within the glassy range of the adhesive, led to strengthening of the joints in shear and to an increase in the glass transition temperature of the adhesive. Similar loading stresses applied at temperatures close to the T_g of the adhesive, led to opposite effects on the above mentioned properties of the joints. The width of the glassy-rubbery transition of the adhesives increased, in the whole range of temperatures used in this study and for all epoxy compositions, as a result of subjecting the joints to superimposed dynamic and static stresses. The broadening of the glass transition was interpreted as a result of the stiffening of polymer network during the combined stressing experiments. A linear relationship was found between the area of endothermal peaks in the first DSC scan of specimens subjected prior to test to superimposed dynamic and static stresses at temperatures below T_g, and the shear strength of the joints. In agreement with this observation and with literature data, a linear relationship was revealed also between the glass transition temperature of the resins (measured in the first DSC scan) and the shear strength of the joints. Based on experimental observations and on some literature information, it was suggested that the strengthening of the joint, as well as the changes in thermal properties of the adhesives, are mainly due to physical processes, such as short-range orientation of network chains and an increase in intermolecular interaction between highly polar sites of the network. The possibility that superimposed stressing led to changes in chemical crosslinking was discussed but it seems that no such reactions occurred.     

Research on Variable Structure and Adaptive Control for Strap-on Rocket

固体捆绑运载火箭变结构自适应控制

陈曦,刘玉玺,汪轶俊

（上海宇航系统工程研究所）

创新点说明：

对于新型固体捆绑火箭而言,由于箭体安装固体助推器,存在推力偏差较大、推力同步性较大的问题,导致火箭的结构干扰增大。安装尾翼外干扰增大,如经过大风区时,风干扰对箭体产生较大的影响。同时考虑建立动力学模型的过程中存在的参数不确定性、参数摄动、三通道间耦合的问题,传统的控制方法难以满足新型固体捆绑火箭的要求,因此本文率先将基于模型参考的变结构自适应控制方法应用于固体捆绑运载火箭上。

研究目的：

本文针对固体捆绑运载火箭控制系统的特点,应用变结构自适应控制理论,设计适用于固体捆绑运载火箭的控制系统,保障固体捆绑运载火箭的正常飞行。

研究方法：

（1）建立固体捆绑运载火箭动力学模型,考虑模型中参数不确定性、未建模动态及通道间耦合;

（2）分析固体捆绑运载火箭存在的干扰,例如：四个固体助推带来的推力偏差、推力不同步性、推力线偏斜,质心横移、芯级、发动机及尾翼安装误差、芯级发动机液体燃料晃动、箭体弹性振动等各类结构误差及风干扰等外干扰;

（3）针对固体捆绑运载火箭设计变结构自适应控制律的设计并证明其稳定性;

（4）Simulink仿真分析验证。

结果：

本文使用变结构自适应控制理论设计的控制系统可全局渐进稳定,三通道姿态角跟踪误差较小,姿态角收敛速度较快,系统性能良好,可有效处理各类结构干扰、外干扰、气动参数不确定性及未建模动态等问题,该控制系统的动态特性及控制品质良好,具有工程应用的前景。

结论：

本文将基于模型参考的变结构自适应控制方法应用于新型固体捆绑运载火箭的控制系统的设计中。给出了仅有俯仰方向有大姿态变动的条件下的火箭动力学偏量模型,并在此基础上设计变结构自适应控制律,同时证明了该控制系统的稳定性。本文通过理论及仿真分析,证明了变结构自适应控制理论在新型固体捆绑运载火箭上的应用可行性,具有一定的工程应用前景。

关键词：运载火箭;模型参考;变结构控制;自适应控制

     

智能电网中电动汽车充电的自适应电价控制方法

针对电动汽车的充电提出一种电价控制策略。聚合管理者集中管理电动汽车的电池,并且考虑用电高峰时电网的电能供给有限,通过电价控制调整充电的需求量。采用自适应动态规划,通过在线网络训练,得到最优的电价策略。仿真结果表明,该自适应电价控制方法能够通过学习电动汽车的移动性和充电过程,从而调整实际充电需求量至期望水平,保证智能电网的稳定运行。     

Research and Application of Dynamic Equation for Full Frontal Impact

Full frontal impact theory needs researching and exploring to satisfy the primary safety design of occupant restraint system,avoiding the increasingly "engineering"trend in order to develop and design safety vehicle. After occupant restraint system is simulated by using linear elastic stiffness k,the occupant-vehicle frontal rigid barrier impact model is established. Dynamic equation of dummy chest coupling vehicle is built for full frontal impact based on ordinary vehicle deceleration by Hooke law,and the equation is solved by comparing coefficient and satisfying boundary qualifications. While relative vehicle characteristic parameters are kept unchanging,the actual vehicle deceleration is fitted to the simplified equivalent square wave( ESW),tipped equivalent square wave( TESW) and equivalent dual trapezoids wave( EDTW). Phase angle  and amplitude A of dynamic equations based on ESW,TESW and EDTW are calculated and deduced. The results show that: the dynamic equation of dummy chest coupling vehicle can be well utilized to instruct the primary safety design of full frontal impact for objective vehicle to satisfy chest deceleration demands and the equation based on TESW is best for this design.     

Finite difference method for dynamic response analysis of anchorage system简

Based on some assumptions, the dynamic analysis model of anchorage system is established. The dynamic governing equation is expressed as finite difference format and programmed by using MATLAB language. Compared with theoretical method, the finite difference method has been verified to be feasible by a case study. It is found that under seismic loading, the dynamic response of anchorage system is synchronously fluctuated with the seismic vibration. The change of displacement amplitude of material points is slight, and comparatively speaking, the displacement amplitude of the outside point is a little larger than that of the inside point, which shows amplification effect of surface. While the axial force amplitude transforms considerably from the inside to the outside. It increases first and reaches the peak value in the intersection between the anchoring section and free section, then decreases slowly in the free section. When considering damping effect of anchorage system, the finite difference method can reflect the time attenuation characteristic better, and the calculating result would be safer and more reasonable than the dynamic steady-state theoretical method. What is more, the finite difference method can be applied to the dynamic response analysis of harmonic and seismic random vibration for all kinds of anchor, and hence has a broad application prospect.     

符号几何规划问题的求解新方法

对符号几何规划问题,给出一种求其全局最优解的分支定界算法。利用不同的凸化方法将算法中关键的定下界操作转化为易于求解的凸规划问题。最后给出算法的收敛性证明和数值实验结果。     

注塑产品动态装配模型的集成知识模型研究

基于MBR(基于模型的推理)技术，建立了注塑模具动态装配结构模型；基于RBR(基于规则的推理)技术，应用面向对象的规则模型(OOR)，建立了动态装配规则的知识表示模型。最后，该文将两种知识表示模型集成，建立了完整的知识模型，为整个系统的后续工作奠定了基础。     

Fuzzy adaptive networks in machining process modeling: surface roughness prediction for turning operations

Due to the complexity of the machine tool structure and the cutting process, the dynamics of machining processes are still not completely understood. This is especially true due to the demand of high-speed machining to increase productivity. In order to model and control these complex processes, new approaches, which can represent complex phenomenon combined with learning ability, are needed. The combined neural–fuzzy approach appears to be ideally suited for this purpose. In this paper, the recently developed fuzzy adaptive network (FAN) is used to model surface roughness in turning operations. The FAN network has both the learning ability of neural network and linguistic representation of complex, not well-understood, vague phenomenon. Furthermore, it can continuously improve the initially obtained rough model based on the daily operating data. To illustrate this approach, a model representing the influences of machining parameters on surface roughness is established and then the model is verified by the use of the results of pilot experiments. Finally, a comparison with the results based on statistical regression is provided.