基于CoSMIC的CCM构件描述

构件描述是CCM（CORBAComponent Model）开发中的一个重要步骤,它是构件部署的基础。本文以雷达A/R显示构件为例详细讲述了在CoSMIC（Component Synthesis with ModelIntegrated Computing）下使用PICML（Platform-Indepndent Component Modeling Language）语言进行构件描述的方法。与直接使用XML（eXtensible Markup Language）语言描述相比,该方法直观简单,层次清晰,提高了开发效率。     

连续导电模式下的单电感多输出DC／DC变换器

系统分析了单电感多输出DC／DC变换器结构,及其采用分时复用原理实现多路输出。由于电感共享,各输出支路间存在着严重的交叉影响。当输出支路严格工作在不连续导电模式（DCM）或伪连续导电模式（PCCM）下,可有效抑制交叉影响。文中采用一种新的控制方式,利用各支路输出电压的共模电压、差模电压分别控制输入半桥、输出半桥占空比,在连续导电模式（CCM）模式下实现了几乎没有交叉影响的多路输出。     

Electroactive Polymer Actuator for Lens‐Drive Unit in Auto‐Focus Compact Camera Module

We propose a lens‐drive unit composed of an ionic polymer‐metal composite (IPMC) for an auto‐focus compact camera module in cellular phones to solve the power consumption problem of voice coil motors which are widely used in commercial products. In this research, an IPMC incorporated into a lens‐drive unit is designed to implement a large displacement in low‐power consumption by using an anisotropic plasma treatment. Experimental results show that a camera module containing IPMCs can control and maintain the position of the lens by using proportional integral derivative control with a photo‐reflective position sensor despite the non‐linear actuation behavior of IPMCs. We demonstrate that the fabrication and commercialization of a lens actuator that has a large displacement and low power consumption using IPMCs is possible in the near future.     

High-Order Coupled Cluster Method (CCM) Calculations for Quantum Magnets with Valence-Bond Ground States

In this article, we prove that exact representations of dimer and plaquette valence-bond ket ground states for quantum Heisenberg antiferromagnets may be formed via the usual coupled cluster method (CCM) from independent-spin product (e.g. Néel) model states. We show that we are able to provide good results for both the ground-state energy and the sublattice magnetization for dimer and plaquette valence-bond phases within the CCM. As a first example, we investigate the spin-half J ₁–J ₂ model for the linear chain, and we show that we are able to reproduce exactly the dimerized ground (ket) state at J ₂/J ₁=0.5. The dimerized phase is stable over a range of values for J ₂/J ₁ around 0.5, and results for the ground-state energies are in good agreement with the results of exact diagonalizations of finite-length chains in this regime. We present evidence of symmetry breaking by considering the ket- and bra-state correlation coefficients as a function of J ₂/J ₁. A radical change is also observed in the behavior of the CCM sublattice magnetization as we enter the dimerized phase. We then consider the Shastry-Sutherland model and demonstrate that the CCM can span the correct ground states in both the Néel and the dimerized phases. Once again, very good results for the ground-state energies are obtained. We find CCM critical points of the bra-state equations that are in agreement with the known phase transition point for this model. The results for the sublattice magnetization remain near to the “true” value of zero over much of the dimerized regime, although they diverge exactly at the critical point. Finally, we consider a spin-half system with nearest-neighbor bonds for an underlying lattice corresponding to the magnetic material CaV₄O₉ (CAVO). We show that we are able to provide excellent results for the ground-state energy in each of the plaquette-ordered, Néel-ordered, and dimerized regimes of this model. The exact plaquette and dimer ground states are reproduced by the CCM ket state in their relevant limits. Furthermore, we estimate the range over which the Néel order is stable, and we find the CCM result is in reasonable agreement with the results obtained by other methods. Our new approach has the dual advantages that it is simple to implement and that existing CCM codes for independent-spin product model states may be used from the outset. Furthermore, it also greatly extends the range of applicability to which the CCM may be applied. We believe that the CCM now provides an excellent choice of method for the study of systems with valence-bond quantum ground states.     

PLED发展现状分析

继CRT显示技术和LCD显示技术之后，PLED／OLED（统称为OEL）显示技术被业界定义为第三代显示技术，而PLED显示则是第三代显示技术中最适宜于大尺寸电视的技术。本文通过对PLED原理、技术、市场、发展状况和应用前景的分析，试图揭示PLED未来的广阔前景。     

Determination the ability of military vehicles to override vegetation

Military operations usually include movement over existing roads and also through natural terrain. Wooded terrain is one of the most challenging environments which affect vehicle mobility. The ability of a vehicle to cross a forest area depends on the possibility of determining if the vehicle is able to manoeuvre between tree stems or can override individual trees. Overriding tree obstacles can be more effective if a vehicle needs a shorter time to cross some tree stems rather than manoeuvring around them. Vehicle movement to cross a forest stand depends on vegetation factors as the stem diameter, stem spacing, and also on tree root parameters, which determine the mechanical tree stability, and a vehicle’s ability to override the trees. Also, the technical parameters (width, length, turning radius, weight, traction force) of the selected military vehicle are important to classify the cross-country movement options. This study describes both the theoretical predictions of the movement of vehicles in forest stands and summarizes the results of one of the most extensive testing of vehicles’ ability to cross individual trees.     

Contemporary Commercial Music (CCM) Survey: Who''s Teaching What in Nonclassical Music

Currently, there is an increasing interest in and demand for training in a wide variety of nonclassical music--contemporary commercial music (CCM)--and most particularly for music theater. A survey of singing teachers was completed to elucidate their training, education, and experience with and methods of teaching CCM. Teachers were at colleges, universities, and conservatories as well as in private studios, both nationally and in several foreign countries. A substantial percentage of those teaching CCM had neither formal education in teaching it nor professional experience. Many of the respondents indicated conflict between classical and CCM styles. Respondents were generally familiar with voice science and voice medicine as well as certain CCM terminology. Teachers expressed an interest in obtaining more information, with an emphasis on healthy vocal production. These results are discussed, as well as implications for the singing teacher who desires specific training to teach CCM.     

PWM型DC-DC LED驱动电路的研究与设计

采用PWM型DC-DC降压拓扑电路结构和闭环恒流控制,设计了LED驱动电路,其工作在CCM模式。该LED驱动电路选用LM2575作为PWM控制芯片,并制作了该电路的实际电路板,其外围元件较少,电路结构简单,适用于中小型LED负载驱动。通过理论分析得到电路元件和各个节点的性能参数,并应用Simulink对DC-DC降压拓扑电路进行仿真。经调试与测量表明,该电路的电气性能良好,负载输出电压纹波在±0.1%以内,功率效率达到45.5%。     

Low-complexity adaptive step size constrained constant modulus SG algorithms for adaptive beamforming

In this paper, we propose two low-complexity adaptive step size mechanisms to enhance the performance of stochastic gradient (SG) algorithms for adaptive beamforming. The beamformer is designed according to the constrained constant modulus (CCM) criterion and the proposed mechanisms are employed in the SG algorithm for implementation. A complexity comparison is provided to show their advantages over existing methods, and a sufficient condition for the convergence of the mean weight vector is established. Theoretical expressions of the excess mean-squared error (EMSE), in both the steady-state and tracking cases, are derived based on the energy conservation approach. The effects of multiple access interference (MAI) and additive noise are considered. Simulation experiments are presented for both the stationary and non-stationary scenarios, illustrating that the proposed algorithms achieve superior performance compared with existing methods, and verifying the accuracy of the analyses.     

Buck变换器在SIMULINK下的建模仿真

Buck变换器具有电路简单和输出电压调节控制性能好的特点,文中主要介绍Buck变换器电路结构和降压原理,定量分析CCM下Buck变换器的小信号分析,及在SIMULINK下的三种建模仿真。实践证明,在电路设计中,利用仿真模型,将会更有效地加快可调功率变换器的设计。