GE RX3i系统设计与虚拟对象应用 第6讲 GERX3i在模块化加工站的设计

模块化加工系统是将定制产品的制造问题通过产品重组和过程重组转化为或部分转化为批量制造问题,即提供给用户的是全新的、定制的个性化产品,而实际产品则主要由标准的模块组成。本文介绍了GE RX3i在模块化加工站中的设计。     

长江三角洲地区城乡收入差距测度

基于GE指数相关理论,测度了长江三角洲的城乡收入差距,测算和分析各种收入来源对城乡之间收入差距的影响度,得出了经营性收入对城乡收入差距的贡献率最大、工资性收入其次、财产性收入和转移性收入贡献率最小等结论。     

选煤自动控制系统

介绍了太原煤炭气化集团有限公司东河选煤厂自动控制系统的组成、配置，实现了逆煤流启车。顺煤流停车及发生事故时急停的自动控制功能。该控制系统结构简单清晰，功能严谨完善，控制效果良好。     

Entropy maximisation and open queueing networks with priorities and blocking

A review is carried out on the characterisation and algorithmic implementation of an extended product-form approximation, based on the principle of maximum entropy (ME), for a wide class of arbitrary finite capacity open queueing network models (QNMs) with service and space priorities. A single server finite capacity GE/GE/1/N queue with R (R>1) distinct priority classes, compound Poisson arrival processes (CPPs) with geometrically distributed batches and generalised exponential (GE) service times is analysed via entropy maximisation, subject to suitable GE-type queueing theoretic constraints, under preemptive resume (PR) and head-of-line (HOL) scheduling rules combined with complete buffer sharing (CBS) and partial buffer sharing (PBS) management schemes stipulating a sequence of buffer thresholds {N=(N₁,…,N_R),0<N_i≤N_i−1,i=2,…,R}. The GE/GE/1/N queue is utilised, in conjunction with GE-type first two moment flow approximation formulae, as a cost-effective building block towards the establishment of a generic ME queue-by-queue decomposition algorithm for arbitrary open QNMs with space and service priorities under repetitive service blocking with random destination (RS-RD). Typical numerical results are included to illustrate the credibility of the ME algorithm against simulation for various network topologies and define experimentally pessimistic GE-type performance bounds. Remarks on the extensions of the ME algorithm to other types of blocking mechanisms, such as repetitive service blocking with fixed destination (RS-FD) and blocking-after-service (BAS), are included.     

影像地图在输电工程中的应用

输电工程中线路路径的选择决定着工程的合理性、经济性,关系着电网的可靠运行与维护,其最优路径选择至关重要.阐述了输电工程的传统设计方法,并着重介绍了影像地图在输电工程野外终勘中的应用.对提高输电工程设计工作效率具有参考意义.     

10吉比特以太网技术特点及应用

2002年6月,IEEE通过的10Gbit/s以太网(10GE)标准,不仅提高了原有以太网技术的带宽和传输距离,并且也为以太网技术的应用扩展到广域网开辟了道路.     

GE90-30 PLC在炼轧厂加热炉系统中的应用

介绍了GE90-30 PLC在加热炉系统改造中的网络拓扑结构,以及其在电气控制、仪表控制中的应用,GE90-30 PLC在加热炉跟踪控制、燃烧控制等系统中表现出良好的控制性能,试投产表明系统稳定性高,能很好的满足工艺要求,为提高产品质量、产量提供了保证。     

基于GE90-30PLC实现的模拟化工过程计算机控制实验系统

本系统采用电子式模拟对象仪,通过组合设计构造了不同的化工过程对象特性,其控制设备采用GE90-30PLC实现数据采集及构成各种不同的控制系统,上位机组态软件选用GE Fanuc自动化监控软件CIMPLICITY HMI 4.01运行版,通过组态设计实现各类控制方案的实验系统,该实验系统可使学生具有面向实际化工过程计算机控制系统的真实感,对于提高学生解决工程实际问题的能力提供了一个非常好的实践平台.     

面向TD-LTE的PTN接入层演进策略研究

随着TD-LTE网络建设规模的加大,并且引入双频组网和载波聚合的技术,现有PTN接入层网络结构无法满足TD-LTE基站的回传需求.通过对PTN接入层网络现状以及TD-LTE业务发展需求的分析,对不同接入场景下的PTN接入层网络提出相应的方案,为LTE传送网接入层演进策略提供参考.     

Comparing alternative cellulosic biomass biorefining systems: Centralized versus distributed processing systems

This study explores how two different cellulosic ethanol production system configurations (distributed versus centralized processing) affect some aspects of the economic and environmental performance of cellulosic ethanol, measured as minimum ethanol selling price (MESP) and various environmental impact categories. The eco-efficiency indicator, which simultaneously accounts for economic and environmental features, is also calculated. The centralized configuration offers better economic performance for small-scale biorefineries, while the distributed configuration is economically superior for large-scale biorefineries. The MESP of the centralized configuration declines with increased biorefinery size up to a point and then rises due to the cost of trucking biomass to the biorefinery. In contrast, the MESP in the distributed configuration continuously declines with increasing biorefinery size due to the lower costs of railroad transportation and the greater economies of scale achieved at much larger biorefinery sizes, including biorefineries that reach the size of an average oil refinery—about 30,000 tons per day of feedstock. The centralized system yields lower environmental impacts for most impact categories than does the distributed system regardless of the biorefinery size. Eco-efficiency analysis shows that the centralized configuration is more sustainable for small-scale biorefineries, while the distributed configuration with railroad transport is more sustainable for large-scale biorefineries. Compared with gasoline from petroleum, cellulosic ethanol fuel offers sustainability advantages for the following environmental impact categories: fossil energy consumption, global warming, human health impacts by particulate matter, ozone layer depletion, ecotoxicity, human health cancer, and human health non-cancer, depending somewhat on the biorefinery sizes and the system configurations.