银杏叶提取物对哮喘大鼠气道嗜酸性粒细胞浸润的影响

目的：观察银杏叶提取物（Egb）对哮喘大鼠气道嗜酸性粒细胞趋化因子（Eotaxin）的表达及嗜酸性粒细胞（EOS）在气道局部浸润的影响。方法：复制哮喘大鼠模型,用免疫组化检测肺组织NF-κBp65亚基及Eotaxin蛋白活性;细胞分类计数法检测支气管肺泡灌洗液（BALF）中EOS的绝对计数和百分比;病理学方法观察气道炎症程度。结果：哮喘组肺组织NF-κBp65（0.256±0.063）及Eotaxin（0.197±0.055）表达量均显著高于正常组（分别为0.015±0.006,0.034±0.008）（均为P〈0.01）。Egb组肺组织NF-κBp65（0.104±0.056）及Eotaxin（0.115±0.010）的表达均显著低于哮喘组（均为P〈0.01）;Egb组BALF中EOS的绝对计数和百分比均低于哮喘组（均为P〈0.01）;光镜下观察Egb组气道炎症较哮喘组显著减轻。结论：哮喘组肺组织NF-κBp65及Eotaxin表达显著增强,Egb能有效抑制哮喘大鼠肺组织NF-κBp65的活性从而抑制Eotaxin的转录合成,减少EOS在局部的浸润,减轻气道炎症。     

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．     

嵌入式手持设备平台设计

本文结合S3C2410X的功能和结构特点,文章基于三星S3C2410X的ARM处理器设计一个可扩展嵌入式手持设备终端平台。文中主要对外围接口电路进行了优化设计,以PCMCIA、液晶触摸屏为例详细说明了接口电路的设计过程。随后分析了针对于手持设备的系统引导部分、操作系统以及图形用户界面系统的软件特点。     

一种新型甲基碘化吡啶的合成与表征

以水合肼、二硫化碳、氯化苄为原料合成了肼基硫代酸苄酯;再以碘甲烷、4-甲酰基吡啶、肼基硫代酸苄酯为原料,合成了新型的有机化合物C16H16N3S2I。其结构经IR、UV、^1HNMR、ESI—MS和元素分析确证。     

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。     

B_4N_4团簇的理论化学计算

使用分子图形软件设计出多种B4N4的同分异构体,然后采用量子化学计算方法的密度泛函理论在B3LYP/6-31G(d)水平下对各个分子进行了全构型优化、谐振频率分析,结果表明有5种构型是势能面上的稳定驻点.对这些构型的几何构型、前线分子轨道和B4N4团簇中原子的成键性质、杂化方式进行了详细地分析.结果表明,B、N原子上加H后有利于分子团簇的稳定.     

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.