摘要：Due to its inherent safety feature, the modular high temperature gas-cooled reactor (MHTGR) has been seen as one of the best candidates in building next generation nuclear plants (NGNPs). Since the MHTGR dynamics has high nonlinearity, it is necessary to develop nonlinear power-level controller which is not only beneficial to the safe, stable, efficient and autonomous operation of the MHTGR but also easy to be implemented practically. In this paper, based on the concept of shiftedectropy and the physically-based control design approach, it is proved theoretically that the simple proportional-differential (PD) output-feedback power-level control can provide globally asymptotic closed-loop stability. Numerical simulation results verify the theoretical results and show the influence of the controller parameters to the dynamic response.

摘要：In this paper, we propose two new explicit Almost Runge-Kutta (ARK) methods, ARK3 (a three stage third order method, i.e., s = p = 3) and ARK34 (a four-stage third-order method, i.e., s = 4, p = 3), for the numerical solution of initial value problems (IVPs). The methods are derived through the application of order and stability conditions normally associated with Runge-Kutta methods;the derived methods are further tested for consistency and stability, a necessary requirement for convergence of any numerical scheme;they are shown to satisfy the criteria for both consistency and stability;hence their convergence is guaranteed. Numerical experiments carried out further justified the efficiency of the methods.

摘要：With the development of optics and microelectronics technology, the portable 3D scanner which is regarded as combination of laser technology, computer science and artificial intelligence have been applied widely in the three-dimensional measuring field, the built-in electromagnetic tracking technology has played an important role in the portable scanner. Combined with the coordinate conversion formula and equipment we can get, using experimental method, we designed the built-in electromagnetic tracking system, using experimental tests, our system can work normally and we accomplished the design and analysis work. This paper is the introduction of this part.

摘要：Adequate damping is necessary to maintain the security and the reliability of power systems. The most-cost effective way to enhance the small-signal of a power system is to use power system controllers known as power system stabilizers (PSSs). In general, the parameters of these controllers are tuned using conventional control techniques such as root locus, phase compensation techniques, etc. However, with these methods, it is difficult to ensure adequate stability of the system over a wide range of operating conditions. Recently, there have been some attempts by researchers to use Evolutionary Algorithms (EAs) such as Genetic Algorithms (GAs), Particle Swarm Optimization, Differential Evolution (DE), etc., to optimally tune the parameters of the PSSs over a wide range of operating conditions. In this paper, a self-adaptive Differential Evolution (DE) is used to design a power system stabilizer for small-signal stability enhancement of a power system. By using self-adaptive DE, the control parameters of DE such as the mutation scale factor F and cross-over rate CR are made adaptive as the population evolves. Simulation results are presented to show the effectiveness of the proposed approach.

摘要：Gravity dams are solid concrete structures that maintain their stability against design loads from the geometric shape, mass and strength of the concrete. The purposes of dam construction may include navigation, flood damage reduction, hydroelectric power generation, fish and wildlife enhancement, water quality, water supply, and recreation. The design and evaluation of concrete gravity dam for earthquake loading must be based on appropriate criteria that reflect both the desired level of safety and the choice of the design and evaluation procedures. In Bangladesh, the entire country is divided into 3 seismic zones, depending upon the severity of the earthquake intensity. Thus, the main aim of this study is to design high concrete gravity dams based on the U.S.B.R. recommendations in seismic zone II of Bangladesh, for varying horizontal earthquake intensities from 0.10 g - 0.30 g with 0.05 g increment to take into account the uncertainty and severity of earthquake intensities and constant other design loads, and to analyze its stability and stress conditions using analytical 2D gravity method and finite element method. The results of the horizontal earthquake intensity perturbation suggest that the stabilizing moments are found to decrease significantly with the increment of horizontal earthquake intensity while dealing with the U.S.B.R. recommended initial dam section, indicating endanger to the dam stability, thus larger dam section is provided to increase the stabilizing moments and to make it safe against failure. The vertical, principal and shear stresses obtained using ANSYS 5.4 analyses are compared with those obtained using 2D gravity method and found less compares to 2D gravity method, except the principal stresses at the toe of the gravity dam for 0.10 g - 0.15 g. Although, it seems apparently that smaller dam section may be sufficient for stress analyses using ANSYS 5.4, it would not be possible to achieve the required factors of safety with smaller dam s

摘要：介绍一种新颖实用的张拉网壳，这种网壳由柔性缆索和刚性杆件组成，按照“拉力连续、压力间断”的思想设计，以最大限度地利用工程材料．本文讨论了这类网壳的几何造型和几何形状的稳定性条件，举例说明了张拉网壳内预应力的确定方法．