几种方圆坯连铸机出坯型式简介

方、圆坯连铸机由于铸坯形状和断面尺寸的区别、冷却和矫直的不同要求、出坯节奏的差异，出坯工艺要求非常不一样，所以出现了众多的出坯设备型式。介绍几种典型的方圆坯连铸机出坯设备型式，以供参考。     

A simple control scheme for a single stage flyback LED driver

This study proposes a simple control scheme for using single‐stage flyback (SSF) converters in lighting source applications for LEDs. Among the advantages of the average current mode is an I/O current ripple that is only one‐half of the critical conduction mode (CRM). This condition helps extend the output capacitor lifetime while lowering the input EMI capacitance input EMI capacitance. The SSF converter proposed in this study operates in continuous conduction mode (CCM). In addition, two sample‐and‐hold (S/H) circuits are placed at the output voltage loop and feed‐forward path, respectively. Since these S/H circuits access the average output current and average feed‐forward voltage, the LED driver is unaffected by the 120‐Hz ripple noise, the total harmonic distortion (THD) is reduced, and the transient response of the output current is improved. Finally, the operation principles and design considerations of the studied LED driver are analyzed and discussed. A laboratory prototype is also designed and tested to verify the feasibility. Copyright © 2014 John Wiley & Sons, Ltd.     

双RCD箝位的双管正激变换器研究

针对传统单管和双管DC-DC变换电路分别存在的高开关应力与低占空比的不足,提出一种双RCD箝位的双管正激变换电路,并对该电路进行了稳态分析及仿真与样机试验验证。结果表明,该电路不仅可将最大可调占空比由普通双管时的0.5提升至0.8左右,而且能使最大开关应力较单管有大幅下降,同时,系统具有开关应力低和可调占空比高的优点。     

低铝脱氧不锈钢夹杂物演变规律分析

为改善2205双相不锈钢的洁净度,在不影响连铸可浇性前提下,通过尝试低铝脱氧工艺,即将成品铝含量控制在0.0045%左右,使钢液中的夹杂物向镁铝尖晶石、钙铝酸盐等类型演变。实验结果表明：精炼结束后钢液全氧含量为15ppm,钢液中的夹杂物固液比例为1,呈半固半液结构;LF精炼阶段夹杂物按“MgO·Al2O3→MgO/MgO·Al2O3→CaO-MgO-Al2O3”的路径进行转变,LF出站得到的CaO-MgO-Al2O3夹杂物与常规铝脱氧得到的CaO-MgO-Al2O3夹杂物在结构组成存在差异：核心为纯MgO,中间层MgO·Al2O3,外层3CaO·Al2O3。     

A correlation framework for the CORBA component model

Large distributed systems, including real-time embedded systems, are increasingly being built using sophisticated middleware frameworks. Communication in such systems is often realized using in terms of asynchronous events whose propagation is implemented by an underlying publish/subscribe service that hooks components into a generic event communication channel. Event correlation—a mechanism for monitoring and filtering events—has been introduced in some of these systems as an effective technique for reducing network traffic and computation time. Unfortunately, even though event correlation is used heavily in frameworks such as ACE/TAO’s real-time event-channel and in mission critical contexts such as Boeing’s Bold Stroke avionics middleware, the industry standard CORBA Component Model (CCM) does not include a specification of event correlation. While previous proposals for event correlation usually offer sophisticated facilities to detect combinations in the stream of incoming events, they have not been constructed to fit within the CCM type system, and they offer relatively little support for transforming and rearranging filtered events into meaningful output events. In this paper, we present the design rationale, syntax, and semantics for a new and highly flexible model for event correlation that is designed for integration into the CCM type system. Our model has been integrated and tested in the Cadena development and analysis framework, which has been designed to support development of mission-control applications in the Boeing Bold Stroke framework. This work was supported in part by the US Army Research Office (DAAD190110564), by DARPA/IXO’s PCES program (AFRL Contract F33615-00-C-3044), by NSF (CCR-0306607) and by Lockheed Martin.     

CORBA构件组装技术研究与应用

本文在对CORBA构件模型以及构件组装技术进行研究的基础上,分析了基于CORBA构件模型的构件组装机制及构件组装的描述方法。在研究的基础上设计出一个具体的构件组装工具,并用此组装工具组装我们的构件,实现了应用系统-水位报警系统。     

A Low‐Complexity 128‐Point Mixed‐Radix FFT Processor for MB‐OFDM UWB Systems

In this paper, we present a fast Fourier transform (FFT) processor with four parallel data paths for multiband orthogonal frequency‐division multiplexing ultra‐wideband systems. The proposed 128‐point FFT processor employs both a modified radix‐2⁴ algorithm and a radix‐2³ algorithm to significantly reduce the numbers of complex constant multipliers and complex booth multipliers. It also employs substructure‐sharing multiplication units instead of constant multipliers to efficiently conduct multiplication operations with only addition and shift operations. The proposed FFT processor is implemented and tested using 0.18 µm CMOS technology with a supply voltage of 1.8 V. The hardware‐ efficient 128‐point FFT processor with four data streams can support a data processing rate of up to 1 Gsample/s while consuming 112 mW. The implementation results show that the proposed 128‐point mixed‐radix FFT architecture significantly reduces the hardware cost and power consumption in comparison to existing 128‐point FFT architectures.     

双馈型风电场详细模型建模方法

提出一种双馈型风电场详细模型的建模方法。所建立的模型可体现风场内每一台风机以及集电系统的电磁暂态过程。该建模方法利用元件连接法(CCM)的思路,首先将风机、集电线路及变压器等视为分立元件,并建立各个元件的详细模型。再根据CCM元件连接规则连接各元件,构成风电场的详细模型。利用该建模方法能够获得系统的非线性微分方程,便于后续利用非线性系统理论进一步对系统展开分析。此外,该模型建立在dq坐标系,稳态时各物理量均为直流,借助线性化工具,可方便地获得风电场在某稳态工作点处的线性化矩阵。通过对比仿真验证了该建模方法的准确性。     

基于C~*Core的动态内存分配方案与实现

为了解决基于C*Core系列芯片嵌入式开发过程中,C*Core系统在某些情况下由于受操作系统、数据格式差异等因素影响,不能动态分配C*Core系列芯片内存的问题,采用数组与标志位相结合的方法,提出一种C*Core系列芯片在所有情况下都通用的动态内存分配方案。该方案利用C*Core C语言编写实现,程序在苏州国芯公司CS32XDV10开发板上运行后,成功实现了动态分配CCM3118芯片内存功能。