科技情报科积极组织放映科技电影

为了普及科学技术知识,厂科技情报科积极组织放映科技电影。1月19～22日,连续放映国产科技片《连体婴儿分离术》,国外科技动态片《电子学》、《阿波罗、联盟号宇宙飞船空中对接》、《房子     

测定复合材料中水份的新方法

NASA兰利研究中心研究出了一种测定纤维增强聚合物复合材料中水分含量及其深度分布的新方法,此法以阳电子寿命与复合材料中水分含量有关为依据。NASA之所以研究这种办法,是因为水分很快使材料降级。 据NASA称,众所周知,还有别的测定水     

航天飞机防热系统——材料的成就

航天轨道器系统,更确切地说,航天飞机是覆盖有防热材料的传统铝合金结构,防热材料的作用是为了再入时使其结构件温度不超过177℃。 那么防热系统的工作状况如何呢?洛克韦尔国际空间研究分部的专家们认为:“防热系统工作得比预想的还要好。在高级材料和加工工程协会的第27届国家讨论会上,克莱西和史     

金属宏观断口形态的数学分析

本文对金属疲劳和脆性宏观断口形态进行了数学分析。分析表明,宏观疲劳弧线的间隔、弯曲方向的改变、偏转、周应力集中时对轴的疲劳弧线的形状及各种情况下的疲劳沟线(台阶),均可用一简单的数学方程式来描述;本文用两种不同的模型(瞬时裂纹前沿线的包络线的垂线和依次生核的裂纹扩展交点的轨迹线)及两种不同的裂纹核心的扩展方式(等功的和等速的)形成的宏观脆性放射线条——即人字纹——进行了数学分析、比较和讨论。     

Gravity and perceptual stability during translational head movement on earth and in microgravity

We measured the amount of visual movement judged consistent with translational head movement under normal and microgravity conditions. Subjects wore a virtual reality helmet in which the ratio of the movement of the world to the movement of the head (visual gain) was variable. Using the method of adjustment under normal gravity 10 subjects adjusted the visual gain until the visual world appeared stable during head movements that were either parallel or orthogonal to gravity. Using the method of constant stimuli under normal gravity, seven subjects moved their heads and judged whether the virtual world appeared to move “with” or “against” their movement for several visual gains. One subject repeated the constant stimuli judgements in microgravity during parabolic flight. The accuracy of judgements appeared unaffected by the direction or absence of gravity. Only the variability appeared affected by the absence of gravity. These results are discussed in relation to discomfort during head movements in microgravity.     

三轴光纤陀螺动态性能测试软件平台设计

本文利用LabVIEW软件所设计的三轴光纤陀螺的动态性能测试软件平台可以完成对转台的姿态控制,实现对转台速度角度的设置;同时完成对运动模拟转台及三轴光纤陀螺的参数采集、存储、处理。通过相关数据处理,实现对相关测试数据及评估结果的直观显示。     

特种雾化喷嘴的试验研究

通过研究特种雾化喷嘴在小环形燃烧室、加力燃烧室及民用工业中的应用 ,设计了扇喷嘴 ,在变几何、变油压、变气流速度下测量了液雾特性、流量分布、雾化角度等。     

含不等长双裂纹无限大板应力强度因子

采用交替法求解了含任意相对位置不等长双裂纹的无限大极受均布拉应力作用的应力强度因子。此法以平面弹性力学的一个问题为基础,即含单裂纹无限大板,裂纹面受集中载荷,此问题的解已知,然后交替地满足边界条件。各种计算结果已绘成曲线。     

某型飞机航炮卡弹停射故障分析

某型飞机执行航炮连续打靶任务中,再次出动时航炮出现空中卡弹停射故障,对其进行机理分析,找出了故障原因,可为后续同类问题的处理提供参考。     

On the stabilization of ribose by silicate minerals

The RNA-world theory hypothesizes that early Earth life was based on the RNA molecule. However, the notion that ribose, the sugar in RNA, is unstable still casts a serious doubt over this theory. Recently, it has been found that the silicate-mediated formose reaction facilitates the stabilization of ribose. Using accurate quantum chemical calculations, we determined the relative stability of the silicate complexes of arabinose, lyxose, ribose, and xylose with the intent to determine which would form predominantly from a formose-like reaction. Five stereoisomers were investigated for each complex. The stereoisomers of 2:1 ribose-silicate are the more stable ones, to the extent that the least stable of these is even more stable than the most stable stereoisomer of the other 2:1 sugar-silicate complexes. Thus, thermodynamically, a formose-like reaction in the presence of silicate minerals should preferentially form the silicate complex of ribose over the silicate complex of arabinose, lyxose, and xylose.