Evaluation of spontaneous baroreflex response after 28 days head down tilt bedrest

The spontaneous baroreflex response was evaluated during supine rest and head up tilt (60 degrees) before and immediately after a 28 day 6 degrees HDT bedrest in 6 healthy adult men (age 30-42 years). Sequences of 3 or more beats where RR-interval and systolic blood pressure changed in the same direction were used to evaluate baroreflex response slope (BRS). Prior to bedrest, the mean BRS and RR-interval were 18.0 +/- 3.9 ms/mm Hg and 926 +/- 61 ms at rest and 10.5 +/- 2.5 ms/mm Hg and 772 +/- 63 ms during the first 10 min of 60 degrees tilt. Following bedrest, these values changed to 15.6 +/- 2.7 ms/mm Hg and 780 +/- 53 ms at rest, and to 6.5 +/- 1.2 ms/mm Hg and 636 +/- 44 ms during tilt. Thus, (1) the spontaneous baroreflex can be evaluated in human subjects during experiments of orthostatic stress; (2) the baroreflex slope was reduced on going from supine to the head up tilt position; and (3) 28 days of bedrest reduced the spontaneous baroreflex slope.     

专家系统的机载应用

随着对机载武器系统的各种威胁力量发展得更加复杂,使得战斗飞机完成既定的任务更加困难,所以必须采用夜视夜战、超低空飞行等更先进的战术,装备各种先进的传感器,从而开发了先进的系统和武器。这种发展的结果,使汇总到驾驶员处的信息流大为增加,要求他实时地接受信息、理解信息、融汇相关、作出选择与判断并及时给出反应操作。这使驾驶员的工作负荷增加到难以接受的程度,尤其在目前战斗飞机向单座舱发展的趋势下,这种情况显得更加突出。例如在战斗机的攻击阶段,驾驶员不但要操纵飞机飞行,而且要搜索截获目标、识别目标、瞄准目标、选择武器及发射顺序、调整飞机姿态、选择投射时机、投射操作,最后退出攻击。与此同时,为保证自身的生存,还必须高度注意     

Toward optimizing lighting as a countermeasure to sleep and circadian disruption in space flight

Light is being used as a pre-launch countermeasure to circadian and sleep disruption in astronauts. The effect of light on the circadian system is readily monitored by measurement of plasma melatonin. Our group has established an action spectrum for human melatonin regulation and determined the region of 446-477 nm to be the most potent for suppressing plasma melatonin. The aim of this study was to compare the efficacy of 460 and 555 nm for suppressing melatonin using a within-subjects design. Subjects (N=12) were exposed to equal photon densities (7.18 x 10(12) photons/cm2/s) at 460 and 555 nm. Melatonin suppression was significantly stronger at 460 nm (p<0.02). An extension to the action spectrum showed that 420 nm light at 16 and 32 microW/cm2 significantly suppressed melatonin (p<0.04 and p<0.002). These studies will help optimize lighting countermeasures to circadian and sleep disruption during spaceflight.     

LHX及其航空电子系统

一、概 况 LHX是美国陆军的轻型直升机验证计划,目的是研制用于90年代先进的轻型侦察/攻击直升机,以代替目前服役中的AH-1、OH-58、OH-6A等几种直升机。本来LHX准备研制两种型号的直升机,即     

一机多型的EH 101直升机及其航空电子系统

介绍了EH101一机多型的直升机的基本情况,及其航空电子系统结构和主要航空电子设备。     

红外点目标探测的信号处理算法及实现

本文讨论了红外点目标探测系统信号处理的各种算法，介绍了使用外场可编程门阵列（ＦＰＧＡ）实现这些算法的方法。     

地形辅助导航

本文阐述了地形辅助导航(TAN)系统及有关技术的概念、基本原理、算法以及发展概况,并与GPS系统进行了比较.讨论了在飞越平坦地形时所存在的问题及解决途径,介绍了TAN的最新发展分支—地形特征匹配(TCM)技术.     

Telescience at the University of California, Berkeley

The University of California at Berkeley (UCB) is a member of a university consortium involved in telescience testbed activities under the sponsorship of NASA. Our Telescience Testbed Project consists of three experiments using flight hardware being developed for the Extreme Ultraviolet Explorer project at UCB's Space Sciences Laboratory. The first one is a teleoperation experiment investigating remote instrument control using a computer network such as the Internet. The second experiment is an effort to develop a system for operation of a network of remote workstations allowing coordinated software development, evaluation, and use by widely dispersed groups. The final experiment concerns simulation as a method to facilitate the concurrent development of instrument hardware and support software. We describe our progress in these areas.     

机载光子技术的发展

航空电子系统的发展已突破了电子范畴,进入了光的谱段,从红外、可见光到紫外,都已有设备投入使用或正在研制,激光技术也以引人注目的姿态进入了机载领域。机载光子技术（airbornephotonics）概念应运而生。虽然它目前仍作为航空电子技术的一个分支,但其发势头很猛,某些先进飞机及研制中的飞机已成为机、电、光的混合世界。光子技术硬件一般是指直接对光信号进行传输、处理,对光数字信号进行逻辑运算或数字运算,或利用光波（或光子）的某种性质或效应进行测量而实现的器件、设备或系统。目前,光子技术的机载应用在以下几个方面比较…