DX-400固态水冷发射机冷却装置概述、技术改进及维护

DX-400发射机是由两台一样的DX-200发射机组成,每个发射机内部都有一个相同的水冷却系统。DX-400采用两个冷却系统并联的方式安装起来,即进水口并联、出水口并联的方式。整个冷却系统通过冷却装置将发射机高压电源系统和功放单元中所有射频功率放大器模块的热量带走,并散发到外部空气中,以保证发射机在正常的温度环境下工作。冷却装置显的至关重要。     

Kevlar纤维表面接枝改性及其稳定化

文章试图通过化学处理方法在Kevlar纤维表面引入活性基团,从而达到对Kevlar纤维进行表面接枝改性的目的。采用红外光谱分析甲苯-2,4-二异氰酸酯(TDI)接枝kevlar纤维的表面组成,用己内酰胺及聚乙二醇PEG(400)对接枝物进行封端稳定化处理;分析了不同n_TDI∶n_PEG值对其产物表面组成的影响。实验结果表明,当n_TDI∶n_PEG=1∶3时, 接枝后红外谱图在3 300 cm-1处的吸收峰强度有所减弱,而在1 700～1 720 cm-1处得到加强;当n_TDI∶n_PEG=1∶1和1∶2时,接枝后红外谱图在3 300及1 700～1 720 cm-1处的吸收峰强度基本相同。n_TDI∶n_PEG=1∶3时稳定化效果最佳。     

Polyethylene glycol(PEG-400): An efficient and recyclable reaction medium for the synthesis of novel 1,5-benzodiazepines and their antimicrobial activity

A new series of imidazole-containing 1,5-benzodiazepines have been synthesized by the condensation of chalcones with ophenylenediamine using piperidine in polyethylene glycol(PEG-400) as an efficient and green reaction solvent.The advantages of this protocol are environmental friendliness,easy work-up,high yields,mild reaction condition and avoidance of expensive catalyst. Furthermore,newly synthesized compounds were evaluated for their antimicrobial activity.     

Binaphthyl-Substituted Chiral Phosphines and Oxides from Binaphthophooles and Nucleophiles

Binaphthophospholes 1 are the starting compounds for the synthesis of chiral phosphine oxides 3 or phosphines 4 via reaction of phospholium salts 2 with nucleophiles. The binaphthyl residue acts as a stereochemical probe for monitoring the integrity of the phosphorus stereocenter.     

Synthesis of quinoxaline derivatives catalyzed by PEG-400

<正>Polyethylene glycol(PEG) was found to be an effective catalyst for the condensation of 1,2-diamines with 1,2-dicarbonyl compounds to afford the corresponding quinoxaline derivatives in excellent yields under mild reaction conditions.     

One-pot synthesis of 2-aminothiazoles in PEG-400

<正>A facile one-pot synthesis of 2-aminothiazoles has been carried in PEG-400 as a greener medium at room temperature.This method avoids the use of lachrymatric a-bromoketones as well as the volatile,toxic organic solvents.     

T400工艺板及其在造纸过程中的应用

对T400工艺板的功能作了简单的介绍，重点说明了T400工艺板的接口，外围连接，软件的组态功能和过程数据通讯，最后介绍了标准软件SPW420的放卷直接张力控制应用。     

单片可编程RF收发芯片CC400的原理及应用

CC400是Chipcon Components公司推出的单片、可编程、半双工UHF收发芯片，可广泛应用于计算机遥控、安防、无线数据的发射／接收等系统。文中介绍了CC400的引脚、内部结构及使用参数，并给出了具体接口应用电路。     

X.400电子邮件的证书管理

Ｘ．４００电子邮件实现加密、签名等安全功能，必须要有证书管理机关来为用户签发证书。证书管理机关不可能只有一个，并且还需与其它系统互通证书。因此，采用分级的方法把多个证书管理机关组织起来，从而使用户能快速、有效地互相验证证书，同时使不同系统的证书也能互相验证。本文对Ｘ．４００下的证书管理作了一些研究，实现了基本框架模型。