Technical evolutions of the French multipurpose instruments for Cognitive Neurosciences

Since the first French flight in space in 1982, the CNES has developed a wide range of instruments, especially in the field of Neurosciences. The design of these instruments has considerably evolved from rather simple equipment up to much more sophisticated tools that are being specially tailored for these missions. Four major phases can be identified: -a simple adaptation of an echographe leading to the first neurosciences experiments (the ARAGATZ'88 mission), -the ILLUSIONS and VIMINAL instruments used during the ANTARES'92 and ALTAIR'93 missions, -the COGNILAB instrument developed for the CASSIOPEE'96 mission, to be re-used in 1997 and in 1999, -a preliminary design of the 1999 mission payload, including virtual reality concepts, in a modular design to adapt to the European COF. Aside from the evolution of scientific requirements, the experience gained during the flights led to progressive improvements in the different technical parts, including visual system, body restraint systems, accessories, such as a force feedback joystick, computer and software, etc. This paper describes the technical evolutions in the CNES Neurosciences program.     

我国战术导弹固体推进技术的现状及发展

综述了我国战术导弹固体推进剂技术的发展现状，分析了我国战术导弹固体推进技术今后发展的主要目标和采用的主要技术途径。     

Cardiovascular deconditioning during weightlessness simulation and the use of lower body negative pressure as a countermeasure to orthostatic intolerance

The cardiovascular function is one of the main disturbed by weightlessness: it is particularly affected by the astronaut's return to Earth, where symptoms linked to the cardiovascular deconditioning syndrom appear in the following forms: (1) orthostatic intolerance with its risk of syncope: (2) higher submaximal oxygen consumption for an equivalent work load. Lower Body Negative Pressure (LBNP) is intended to stimulate the venous system of the lower limbs; however, the specific effects of periodical LBNP sessions on the orthostatic intolerance have never been studied. With this objective in mind, 5 volunteers took part in two recent antiorthostatic bedrest experiments for 30 days. In the first experiment 3 subjects were submitted to several sessions of LBNP experiment per day and 2 others were controls; in the second experiment the LBNP group of the 1st one became controls and vice-versa. Two orthostatic investigations were performed: (1) 5 days before the bedrest; (2) at the end of the 30 day bedrest period. The results showed: (1) when the subjects were control, a high orthostatic intolerance post bedrest with 3 syncopes and one presyncopal state during the first minutes of the tilt test; (2) when the subjects were submitted to LBNP sessions, no orthostatic intolerance.     

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.     

浅议英语听力教学中背景知识的作用及强化

从词义的文化差异、语句的运用差异、篇章的背景知识及强化来说明文化背景知识在英语听力教学中的重要性。     

宽覆盖多光谱CCD相机模装及模态分析

文章以结构设计软件AutoDesk Inventor对宽覆盖多光谱CCD相机结构进行精确造型、模装，进行了干涉检查。应用大型结构分析软件PATRAN、NASTRAN，建立了该相机超大规模有限元模型，完成了该相机的模态分析，得出了该相机相应的固有频率和模态，验证了相机结构设计的合理性。     

钛合金薄壁零件的切削加工

论述铁合金材料的切削加工特点。介绍钛合金材料在切削加工时的切削用量、刀具材料及几何参数的合理选择。提出了钛合金薄壁零件新的加工工艺方法．     

在CAD系统上探索空间飞行器三维动画的实现途径

说明了在CAD系统上实现三维模型动画的可行性,接着论述了三维物体的运动控制方法及在CAD 系统上实现的技术途径。给出了在微机Auto CAD上利用关键帧技术和运动算法控制模拟空间飞行器运动的一些实例,同时也介绍了在Euclid-IS CAD 系统上二次开发运动模拟功能的探索。     

坦克主动防护系统发展——拒敌于“咫尺”之外

“防御并不是一面简单的防盾，而是一种良好指导的防御所构成的防盾”卡尔&;#183;冯&;#183;克劳塞维兹。坦克的装甲与反装甲武器之间的发展总是道高一尺、魔高一丈，装甲与反装甲技术一时之间可能是某一方领先。竞争是永无止境的，然而就其基本逻辑而言，装甲相对却是居于劣势的一方；反装甲武器顺攻击之时总是集中破坏一处的装甲，但装甲却必须防护全车，正所谓备多而力分。幸好反装甲武器哑袭的方向并不平均，过去的作战记录显示，45%的攻击来自正面左右各30度的范围，无怪乎坦克常在车体与炮塔下面提供最厚重的装甲保护，不过，这种传统的装甲防护模式目前正面临严重的挑战。