Far-UVC light as a new tool to reduce microbial burden during spacecraft assembly

This work aims to investigate far-UVC light at 222 nm as a new microbial reduction tool for planetary protection purposes which could potentially be integrated into the spacecraft assembly process. The major advantage of far-UVC (222 nm) compared to traditional germicidal UVC (254 nm) is the potential for application throughout the spacecraft assembly process in the presence of humans without adverse health effects due to the limited penetration of far-UVC light into biological materials. Testing the efficacy of 222-nm light at inactivating hardy bacterial cells and spores isolated from spacecraft and associated surfaces is a necessary step to evaluate this technology. We assessed survival of Bacillus pumilus SAFR-032 and Acinetobacter radioresistens 50v1 exposed to 222-nm light on proxy spacecraft surfaces simulated by drying the bacteria on aluminum coupons. The survival fraction of both bacteria followed a single stage decay function up to 60 mJ/cm², revealing similar susceptibility of both species to 222-nm light, which was independent of the exposure rate. Irradiation with far-UVC light at 222 nm is an effective method to decontaminate the proxy spacecraft materials tested in this study.     

高速低压差分信号（LVDS）器件应用设计方法研究

随着高速LVDS器件得到广泛应用，在高速信号使用LVDS传输时，信号传输线路问题、信号传输波形的最佳化成为非常重要的课题之一。由于印制电路板的布局布线直接影响信号传输质量，因此利用仿真对印制板分析成为设计上不可缺少的手段。有鉴于此，文章深入探讨了高速电路的设计，总结出设计技巧。     

辐射发射参考源在EMC比对中的应用

辐射发射参考源是在对EMC测试系统进行比对测试和定期场地校验时必不可少的设备,介绍了辐射发射参考源的原理和特点、各种实现方式、国内外应用概况及其稳定性考核措施。     

高速低压差分信号(LVDS)器件应用设计方法研究

随着高速LVDS器件得到广泛应用,在高速信号使用LVDS传输时,信号传输线路问题、信号传输波形的最佳化成为非常重要的课题之一。由于印制电路板的布局布线直接影响信号传输质量,因此利用仿真对印制板分析成为设计上不可缺少的手段。有鉴于此,文章深入探讨了高速电路的设计,总结出设计技巧。     

总量控制与排污权交易的理论分析

本文从总量控制与排污权交易的概念出发，论述了排污权交易的基本理论和市场机制模型，分析了总量控制与排污权交易的经济、环境和社会效益，阐述了排污权的初始分配方式及交易方式。     

Cyclotron masers and solar spike bursts

The theory of electron cyclotron maser emission and its application to solar spike bursts are reviewed. By analogy with the Earth's AKR, three sources of free energy are considered: a loss-cone anisotropy, a velocity-space hole, and a trapped distribution. The problem of how the radiation escapes through the second harmonic absorption layer is emphasized. Harmonic emission due to z mode coalescence may operate for some bursts, but the 2–5s delay between hard X-ray bursts and spike bursts suggests that some other mechanisms is required for most spike bursts. A model involving formation of a trapped distribution in low-density regions neighboring the flaring flux tube is considered.     

一种实用型报警装置的研制

本文综合地运用了５５５集成电路，ＴＷＨ９２４８，ＴＷＨ９２４９雷达式扫描探测传感集成电路的ＳＲ９Ｇ２６Ａ／Ｄ、Ｄ／Ａ转换语音存放电路等，中大规模集成电路。并利用一种简单的高频发射线路，而研制成的实用型报警装置。     

应用声发射技术实时监测某型机防扭支架疲劳试验裂纹

随着声发射技术的发展,声发射技术在工程无损检测上的运用日益广泛。本文对声发射技术的应用现状、基本理论及在直升机某型机防扭支架疲劳试验裂纹监测中的应用进行了介绍。希望通过应用声发射技术,能及时捕捉疲劳裂纹形成和扩展的过程,给判定疲劳试验件是否破坏带来更准确、客观的依据,从而能为直升机动部件和结构件的准确定寿提供一种科学的辅助手段。     

大型转动机械碰摩故障分析的声发射检测系统

汽轮发电机、空气压缩机等采用油膜支撑的大型转动机械,由于安装或运行中的原因,在转子旋转过程中,可能和器壁发生轻微的摩擦和碰击,简称碰摩.声发射技术在碰摩发生特别是故障早期诊断上有优越性.本系统的特点是没有沿用传统的计数、幅度、能量和持续时间等声发射特性参数,而是在声发射包络信号的频率分析中进行特征提取.声发射发生的过程分析和现场试验都表明这种方法对碰摩检测很敏感,在碰摩发生的起始阶段,包络谱中与转速同步的周期性分量显著增加.根据这种新的设计思想自行研制了BUAA碰摩声发射检测仪并对此作了介绍.     

Using gamma-ray burst prompt emission to probe relativistic shock acceleration

It is widely accepted that the prompt transient signal in the 10 keV–10 GeV band from gamma-ray bursts (GRBs) arises from multiple shocks internal to the ultra-relativistic expansion. The detailed understanding of the dissipation and accompanying acceleration at these shocks is a currently topical subject. This paper explores the relationship between GRB prompt emission spectra and the electron (or ion) acceleration properties at the relativistic shocks that pertain to GRB models. The focus is on the array of possible high-energy power-law indices in accelerated populations, highlighting how spectra above 1 MeV can probe the field obliquity in GRB internal shocks, and the character of hydromagnetic turbulence in their environs. It is emphasized that diffusive shock acceleration theory generates no canonical spectrum at relativistic MHD discontinuities. This diversity is commensurate with the significant range of spectral indices discerned in prompt burst emission. Such system diagnostics are now being enhanced by the broad-band spectral coverage of bursts by the Fermi Gamma-Ray Space Telescope; while the Gamma-Ray Burst Monitor (GBM) provides key diagnostics on the lower energy portions of the particle population, the focus here is on constraints in the non-thermal, power-law regime of the particle distribution that are provided by the Large Area Telescope (LAT).