System design and analysis of the trans-critical carbon-dioxide automotive air-conditioning system

INTRODUCTIONAftertheKyotoProtocolwassigned ,theworldwiderefrigerationandair conditioningin dustryfaceduptogreatchangesintheenviron mentalproblem .Forautomotiveair conditioning(AAC) ,thecurrentrefrigerant,R 13 4a ,hasbeenregardedasrestricted use refrigeran…     

夏热冬冷地区某综合楼空调冷热源优化研究

根据夏热冬冷地区的气候特点、建筑使用功能和建筑周边资源现状,对某综合楼空调冷热源方案的选择进行比较研究。通过比较优化前后冷热源方案,对其初投资、运行费用、舒适性、稳定性等因素进行综合分析,结果表明当建筑规模较大且需提供空调及热水时,模块式风冷热泵（热回收）系统优越于多联机 VRV 加独立热源系统。     

Genetic optimization algorithm of PID decoupling control for VAV air-conditioning system

Variable-air-volume (VAV) air-conditioning system is a multi-variable system and has multi coupling control loops. While all of the control loops are working together, they interfere and influence each other. A multivariable decoupling PID controller is designed for VAV air-conditioning system. Diagonal matrix decoupling method is employed to eliminate the coupling between the loop of supply air temperature and that of thermal-space air temperature. The PID controller parameters are optimized by means of an improved genetic algorithm in floating point representations to obtain better performance. The population in the improved genetic algorithm mutates before crossover, which is helpful for the convergence. Additionally the micro mutation algorithm is proposed and applied to improve the convergence during the later evolution. To search the best parameters, the optimized parameters ranges should be amplified 10 times the initial ideal parameters. The simulation and experiment results show that the decoupling control system is effective and feasible. The method can overcome the strong coupling feature of the system and has shorter governing time and less over-shoot than non-optimization PID control.     

老年急性非结石性胆囊炎临床特点及手术治疗

目的:探讨老年人急性非结石性胆囊炎(AAC)临床特点与手术治疗.方法:通过设立病例对照,对48例老年人AAC和急性结石性胆囊炎(ACC)的并发症、胆囊病理改变及术后结果进行比较.结果:与老年人ACC相比,AAC患者以心血管疾病为主的并发症明显增多(P＜0.01);胆囊化脓、坏疽与穿孔率明显增高(P值＜0.01,＜0.01,＜0.05);术后并发症发生率明显上升(P＜0.01).结论:老年人AAC并存病多、胆囊病变重、术后并发症发生率高;宜在症状出现48h内手术治疗.     

Life cycle cost analysis of new FRP based solar parabolic trough collector hot water generation system

Parabolic trough collectors （PTCs） are employed for a variety of applications including steam generation and hot water generation. This paper deals with the experimental results and an economic analysis of a new fibre reinforced plastic （FRP） based solar PTC with an embedded electronic controlled tracking system designed and developed for hot water generation in a restaurant in Madurai, India. The new collector performance has been tested according to ASHRAE Standard 93 （1986）. The performance of a new PTC hot water generation system with a well mixed hot water storage tank is investigated by a series of extensive tests over ten months period. The average maximum storage tank water temperature observed was 74.91℃, when no energy is withdrawn from the tank to the load during the collection period. The total cost of the new economic FRP based solar PTC for hot water generation with an embedded electronic controlled tracking system is Rs. 25000 （US$ 573） only. In the present work, life cycle savings （LCS） method is employed for a detailed economic analysis of the PTC system. A computer program is used as a tool for the economic analysis. The present worth of life cycle solar savings is evaluated for the new solar PTC hot water generation system that replaces an existing electric water heating system in the restaurant and attains a value of Rs. 23171.66 after 15 years, which is a significant saving. The LCS method and the MATLAB computer simulation program presented in this paper can be used to estimate the LCS of other renewable energy systems.     

IDS中扫描系统的分析与设计

入侵检测系统包含：扫描系统、主体IDS,IDS审计分析系统三个部分,其中扫描系统是IDS设计中非常重要的部件,包括扫描器、弱点(漏洞)数据库,以及分布在各主机上的扫描子系统。本文从扫描器的原理、网络扫描器的设计进行详细的介绍。     

基于RFID的智能仓储管理系统的研发

介绍了RFID技术的基本概念、特点及应用，讨论了基于RFID的智能仓储管理系统的典型框架结构、主要特点及功能模块，与传统的识别方式相比，具有无需直接接触、无需光学可视、无需人工干预即可完成信号输入和处理、操作快捷方便等优点，初步实验表明了本设计方案的合理性和实用性。     

IPTV系统组成及关键技术

IPTV是一种集互联网、多媒体、通信等多种技术于一体的全新系统,在从内容制作到终端接收的整个实现过程中,涉及到包括编码、数字版权管理、内容分发网络、机顶盒等许多关键技术,本文对这些关键技术进行了详细介绍和分析,并针对现有IPTV集中交换模式的缺陷,提出了基于集中式P2P技术的IPTV系统,提高了IPTV服务质量和系统性能。     

宽带CMOS LC压控振荡器设计及相位噪声分析

应用标准0.18μm CMOS工艺设计并实现了宽带交叉耦合LC压控振荡器.采用开关电容阵列拓宽频率范围.设计过程中对相位噪声进行了优化.应用线性时变模型(LTV)推导出相位噪声与MOS晶体管宽长比之间的函数关系,从理论上给出相位噪声性能最优的元件参数取值范围.为简化推导过程,针对电路特点按晶体管工作状态来细分电路工作区域,从而避免了大量积分运算,以尽可能简单的比例形式得到相位噪声与设计变量间的函数关系.测试结果表明,在1.8V电源电压下,核心电路工作电流为8.8mA,压控振荡器的频率范围为1.17 ～1.90GHz,10kHz频偏处相位噪声达到-83dBc/Hz.芯片面积为1.2mm×0.9mm.     

Optimization design and residual thermal stress analysis of PDC functionally graded materials

INTRODUCTION Polycrystalline diamond compacts (PDC), con-sisting of a polycrystalline diamond (PCD) layer on a WC-Co substrate, and having high hardness and abrasive resistance, are used in a variety of drilling and machining applications (Farhad, 2001; Sadi and Muzaffer, 2001). However, due to differences of thermal and mechanical properties in diamond and WC-Co substrate, residual thermal stresses develop in regions near the interfaces during fabrication. The diamond coating exhib…     

无线电能传输TS-S型补偿网络的建模与设计

补偿网络是无线电能传输系统中的重要组成部分,可用于提高电能传输的效率、输出功率及稳定性。在对TS-S型补偿网络建模及其参数化设计分析的基础上,采用算例验证TS-S型补偿网络模型的定频谐振、恒定电压增益和高效率特性,通过实验验证相关推论及方法。结果表明,样机电压输出稳定,在耦合系数为0.2时的效率峰值达到90%。     

空调冷热源选择智能决策支持系统知识库与推理机的构造与实现

根据空调冷热源方案选择的特点 ,对面向该领域问题的知识表达方式和推理控制策略进行了分析 ,提出了知识库和推理机的构造思想和工作过程 ,探讨了C语言开发环境下的实现方法 .采用领域工程师为主体的开发方式 ,开发了一个基于此知识表达和推理机制的空调冷热源选择智能决策支持系统模型软件 .经测试表明 ,该软件具有内核小、表处理及数据驱动能力强的特点 ,在某大型办公楼空调冷热源系统设计中获得了成功应用 .     

产品全生命周期设计及其应用

给出了产品全生命周期设计的定义，阐述了全生命周期设计的内容和方法，探讨了实现全生命周期设计的关键技术，并开发了基于SolidWorks的面向装配的设计工具(DFA)。     

New analytical solution for the analysis and design of permanent magnet thrust bearings

On the basis of the current sheet model, a new analytical solution for permanent magnet （PM） bearings is developed. Compared with analytical methods based on the coupling energy model and the magnetic dipole model, the proposed one is more physically intuitive and convenient for engineering designers. According to the analytical model, the thrust characteristics of a novel PM thrust bearing is studied and verified by finite element analysis （FEA）. In the proposed thrust bearing configuration, the rotor is composed of stacked PM tings with alternative axial magnetization directions, and the stator with alternative radial magnetization directions while copper rings are used to separate adjacent PM rings. A prototype PM thrust bearing with the proposed configuration is designed and fabricated. The performances of the PM thrust beating are experimentally validated. It is shown that the calculation accuracy of the presented analytical solution is satisfying.     

Integration and verification case of IP-core based system on chip design

In this paper, the design and verification process of an automobile-engine-fan control system on chip （SoC） are introduced. The SoC system, SHU-MV08, reuses four new intellectual property （IP） cores and the design flow is accomplished with 0.35 btm chartered CMOS technology. Some special functions of IP cores, the detailed integration scheme of four IP cores, and the verification method of the entire SoC are presented. To settle the verification problems brought by analog IP cores, NanoSim based chip-level mixed-signal verification method is introduced. The verification time is greatly reduced and the first tape-out achieves success which proves the validity of our design.     

Overall plan and design of the task management system of ternary optical computer

In this paper an overall scheme of the task management system of ternary optical computer (TOC) is proposed, and the software architecture chart is given. The function and accomplishment of each module in the system are described in general. In addition, according to the aforementioned scheme a prototype of TOC task management system is implemented, and the feasibility, rationality and completeness of the scheme are verified via running and testing the prototype.     

酉阵和非酉阵预编码的输出SINR分析

在LTE(Long Term Evolution)的预编码技术中,预编码矩阵存在着使用酉阵和非酉阵的选择。本文分析了酉阵预编码的输出SINR的形式,提出了一种简化计算输出SINR计算的方法,计算4个矩阵(8个矢量)的输出SINR操作复杂度下降到原始方法的18%。同时分析了非酉阵预编码时的输出SINR相比于使用酉阵时的损失。仿真结果表明,非酉阵预编码相比于酉阵预编码在输出SINR上会有损失,这种损失从统计上可以用线性关系近似描述。     

Siemens 200仿真软件在PLC控制系统设计中的应用

介绍了Siemens仿真软件对Siemens200系列可编程控制器的常用编程方法、继电器电路设计梯形图的经验设计法和顺序功能图设计法所设计出的程序进行了仿真验证,并对相应时序变量实时监测。结果表明,该方法效果完全与硬件调试一致,为教学和工程实际实践提供了一种非常有用的方法。     

利用FDTD方法全波分析与设计管道中用于整流天线的微带天线

1 Introduction In some nuclear power plants , chemical plants ,power plants ,the pipe cracks detection is very diffi-cult because of its thinness and fatalness . So the in-pipe inspection micromachine is developed . The rec-tenna (rectifying antenna) ,rec…     

基于SLS技术的汽车油过滤器接头零件快速原型制造

为了快速获得汽车油过滤器接头零件的样件，提出了基于SLS技术的快速原型制造技术，介绍了SLS技术的成型原理、成型工艺过程以及烧结汽车油过滤器接头零件时工艺参数的确定。