中原城市群的城市规模结构分析

本文选用城市的首位度,城市金字塔,以及位序-规模法则对中原城市群九个城市的规模结构以及未来趋势进行分析,得出中原城市群发展中存在的问题,以及解决这些问题的相关对策。     

长尾理论给网络出版带来的启示

作为对我们所熟知的“80／20法则”的悖反或补充,“长尾理论”被《商业周刊》评为2005年度最有商业价值的概念之一。该理论认为,运用信息技术可消除传统商业世界的很多约束,以至于需求不旺或销售不佳的产品共同占据的市场份额,可以和那些数量不多的热卖品占据的市场份额相匹敌甚至更大。长尾理论作为网络商业的一个新的理论基础,为网络出版的发展带来启示。     

博物馆国内游客特征探究——以武汉辛亥革命博物馆为例

文章以辛亥革命博物馆为例,通过对其游客行为的考察和分析,得出反映特定历史事件的专题性博物馆目前尚无法成为中部地区城市旅游资源开发利用的核心的结论,对以武汉市为代表的中部地区城市的专题性文化旅游产品开发经营以及其他历史文化型景点的运作具有一定的参考意义。     

ICL7135在单片机自动打包系统中的应用

分析ICL7135的工作原理与串行输出时序,利用单片机的INT0中断和计数器TO设计ICL7135与单片机AT89S52的接口电路,并将其应用于自动打包系统,实验效果良好。     

4位半积分式数字直流电压表设计

A／D转换环节直接影响仪表的测量精度和分辨率,本文通过数字直流电压表的硬件电路及软件的设计,给出了以89C51单片机为核心、以分立元件制作的双积分型A／D转换器为主要部件的4位半积分式数字直流电压袁的设计方案,并对所设计的电压表进行了测试,结果测量误差≤±0．03％,精度达到4位半。实现了自动量程转换功能,有很好的实际应用价值。     

STS教育思想的特点及在《科学·化学》中的渗透

STS教育是科学教育改革中兴起的强调理解科学、技术和社会三者关系的一种新的科学教育思想。其宗旨是普及STS知识,培养具有科学素质的公民,使人们形成一种科学、科技与社会可持续发展的新的价值意识——STS意识。基于小学教师培养的高师《科学·化学》课程改革应当在教材建设和教学实践等方面充分体现和渗透STS教育思想,使其具有时代性和社会功能价值。     

ICL7129的自动量程转换控制

利用双积分单片A／D转换器ICL7129自身的特殊结构特点,加极简单的外围电路即可构成一个两个量程自动转换的数字仪表．叙述其电路原理及实用的电路．     

基于嵌入式技术网络测试仪的研究及设计

本文就网络发展现状进行分析,重点研究了嵌入式技术,C8051F340处理器和TCP/IP协议。提出了一种基于嵌入式技术的网络终端测试仪的设计。     

In-package P/G planes analysis and optimization based on transmission matrix method

Power integrity （PI） has become a limiting factor for the chip＇s overall performance, and how to place in-package decoupling capacitors to improve a chip＇s PI performance has become a hot issue. In this paper, we propose an improved transmission matrix method （TMM） for fast decoupling capacitance allocation. An irregular grid partition mechanism is proposed, which helps speed up the impedance computation and complies better with the irregular power/ground （P/G） plane or planes with many vias and decoupling capacitors. Furthermore, we also ameliorate the computation procedure of the impedance matrix whenever decoupling capacitors are inserted or removed at specific ports. With the fast computation of impedance change, in-package decoupling capacitor allocation is done with an efficient change based method in the frequency domain. Experimental results show that our approach can gain about 5× speedup compared with a general TMM, and is efficient in restraining the noise on the P/G plane.     

Polychlorinated dibenzo-p-dioxins and dibenzofurans in flue gas emissions from municipal solid waste incinerators in China

Polychlorinated dibenzo-p-dioxins and furalls(PCDD/Fs)emissions in flue gas from two types of municipal solid waste incinerators(MSWIs)most commonly used in China were investigated in this study.The selected incinerators include two grate-type MSWIs:MSWl-A(350 t/d)and MSWI-B(150 t/d),and two fluidized bed MSWIs:MSWI-C(400 t/d) and MSWI-D (400 t/d),which are all equipped with semi-dry lime scrubber and bag filter except MSWI-D equipped with cyclone and wet scrubber(WS)as air pollutant conffol device(APCD).Results indicated that the emission concentration and the international toxic equivalents(I-TEQs)of the PCDD/Fs from the stacks were in the range of 1.210～10.273 ng/Nm3 and 0.019～0.201 ngI-TEQ/Nm3,respectively.They were greatly lower than the emission regulation standard of PCDD/FS in China(1.0 ng I-TEQ/Nm3).However,only the PCDD/Fs emission Ievel from MSWI-C Was below 0.1 ng I-TEQ/Nm3.Although the homologue profiles were distinct,the contributions of the 2,3,7,8-subsituted congenem to the total I-TEQ were similar among all the investigated MSWIs.Two major 2,3,7,8-substituted congeners,2,3,4,7,8-PeCDF and 1,2,3,7,8-PeCDD,account for 47% and 9%(average values)of the total I-TEQ values,respectively.The correlation between PCDD/Fs levels and composition of flue gas Was also discussed.