String Block Vs Superblock Patterns of Dispersal in China

The superblock in China has become the dominant unit of urban planning, allowing for rapid urban growth while also meeting the needs of state and property developer alike. Kjersti Monson explains the conditions that have given rise to the superblock, while challenging it by proposing an alternative ‘stringblock’ approach, rooted more in collective culture and addressing the demands of the market-driven economy. Copyright © 2008 John Wiley & Sons, Ltd.     

催化裂解Ⅱ型装置首次应用MGD技术的工业试验

对催化裂解Ⅱ(DCC-Ⅱ)型装置进行多产液化气和柴油裂化技术(MGD)改造。根据装置特点,分别进行了提升管的预提升段和反应床层的稳定汽油回炼改造。改造前后进行了标定。标定结果显示,丙烯产率提高1.5～1.7个百分点,总轻烃液收增加1.0～1.2个百分点。汽油的烯烃体积分数降低6～10个百分点,芳烃体积分数增加4～5个百分点,辛烷值提高约1个单位。改造后的DCC装置可以根据不同季节、不同的市场需求和产品价格变化情况灵活生产。     

FCC家族新技术在向化工型炼油厂转型过程中核心桥梁角色

The emerging FCC-based technologies of on-purpose light olefins (mainly refer to ethylene & propylene) as well as light aromatics (refer to BTX) production developed by RIPP, SINOPEC, including Deep Catalytic Cracking (DCC), Enhanced Deep Catalytic Cracking (DCC-PLUS) and Maximizing Catalytic Propylene (MCP), have been playing core bridging roles in the processing of the closer integrations & shifts of petroleum refining and petrochemical production both in China and outside of China since 1990. Three cases of commercial applications in five refineries, including Case I-Closer integration between steam cracker and DCC/DCC-PLUS Unit, Case II-Petrochemical refinery with DCC-PLUS unit, and Case III-Integrated Petrochemical/Fuels refinery with MCP unit, have highlighted their effects to global petrochemical productions.     

L-脯氨酰-L-苯丙氨酸二肽合成的实验教学研究

介绍Boc-L-脯氨酸与L-苯丙氨酸甲酯盐酸盐通过DCC-HOB t缩合、羧基脱保护、氨基脱保护3步反应合成L-脯氨酰-L-苯丙氨酸二肽的实验教学研究。该实验简便易操作,反应时间短,实验所用到的试剂、样品安全无毒,且涉及的重要基本单元操作及综合表征手段多种多样,非常适合化学化工及相关专业的高年级本科生作为科研型教学实验使用。     

WDM系统中电监控信道方法的研究

波分复用(wavelength-Division Multiplexing,WDM)技术的发展大大提高了通信网络的传输容量,将成为下一代骨干网络的核心传输方式.在WM系统光网元设备之间的通信方法中,较多的是采用光监控信道(OSC)和调顶技术(Pilot Tone),但是这两种方法的固有缺陷在城域波分系统不可避免,从而引出电监控信道(ESC)一适用于城域波分系统的基于业务开销中现有的DCC字节来进行网元之间通信的一种实现方法.该方法易于实现、可靠性高,有效降低了系统成本,提高了系统资源利用率,有较好的应用前景.     

Motion artifact elimination technology for liquid‐crystal‐display monitors: Advanced dynamic capacitance compensation method

Abstract— A new technology, advanced dynamic capacitance compensation (A‐DCC), for improved dynamic performance of LCD monitors, is presented. Conventional LCD monitors suffer from certain specific artifacts, such as wire‐frame flicker and line dimming, which are not issues for the simpler motion images found in television content. A‐DCC addresses these more‐challenging monitor cases by means of an advanced architecture which analyzes multi‐frame data and applies more comprehensive lookup‐table corrections according to the specific frame sequence.     

DCC-气体分离装置热集成方案分析评价

DCC(Deep Catalytic Cracking)是一种多产丙烯的深度重油催化裂解工艺。与常规的催化裂化装置相比,DCC装置的吸收稳定系统和下游的气体分离(简称气分)装置需要更多的中低温位热量。因此,DCC与气分装置的热集成方案对装置的低温余热系统、蒸汽产耗平衡和冷却负荷有着重要的影响。采用分析方法,借助流程模拟工具及能级-热量图,量化分析了DCC与气分装置的2种热集成方案,包括基于循环热媒水的直接热联合方案,以及基于热泵工艺的热联合方案。与直接热联合方案相比,热泵方案的换热过程损可减少13.1%,1.0 MPa蒸汽消耗量可降低20t/h;但是直接热集成方案的设备投资低。结果表明,DCC和气分装置中低温热源热阱的优化匹配是提高装置用能效率的重要因素。     

基于直接电流控制的BLDCM换相转矩脉动抑制

无刷直流电机传统的脉宽调压控制方式存在较大的换相转矩抖动,限制了它在高精度伺服控制系统中的应用。该文详细分析了无刷直流电机非换相电流与输出转矩与之间的关系,并以该电流为控制对象,研究了一种直接电流控制方式,结合两相导通控制模式,实现对电流的直接控制,进而控制转矩抖动。利用MATLAB软件将该控制方法与脉宽调压控制方法作对比仿真分析,仿真及实验结果证明,该控制方法能有效解决相电流及转矩波动较大的问题,并具有更好的负载响应速度和稳态性能。     

Clock buffer with duty cycle corrector

A clock buffer with duty cycle corrector circuit is presented. The proposed circuit can generate either 50% duty cycle or conserve the duty cycle as input clock. It corrects the input duty cycle of 10-90% for generated 50% duty cycle of output clock with error less than 0.9%. Moreover, it enhances the input clock signal driving ability and keeps the same duty cycle as input clock within range from 20% to 80% with a maximum duty error of 0.5%. The proposed circuit operation frequency range is from 100 MHz to 1 GHz. The proposed circuit has been fabricated in a 0.18 μm CMOS technology.     

基于3DCC的微机组装与维护课程教学模式的探究

微机组装与维护是一门实践性、即时性都很强的课程。本文从实际的教学现状调研出发,针对在该教学过程中存在的问题和难点,结合自身实际教学的经验和体会,提出了一种基于3DCC的微机组装与维护的教学模式。实践表明,本文中所设计和实现的教学模式能够有效、合理的应用于现代的微机组装与维护教学环境中,以提高学生的技术水平与实际操作能力,并取得了良好的教学效果。