Origin of informational polymers and the search for non-terran life: protection of the polymeric state of DNA by phosphate minerals

An in-depth analysis of the effects exerted on the DNA backbone by 25 crystal phosphate minerals is reported. Degradation of DNA oligomers was performed with two different reactions: Hydrolysis following Nucleophilic Degradation (HND), initiated by the nucleophilic addition of formamide on both purine and pyrimidine nucleobases, and Hydrolysis following Nucleophilic Substitution (HNS) carried on by water and starting with the removal of a nondegraded base. A complete panel of effects on the phosphoester bonds, from protection to enhanced instability to absence of interference, is described. These effects differ in the different degradation pathways and in different physical-chemical conditions. The relationship between the hardness of the mineral and its protective ability is discussed. In addition to its interest per se, this study was prompted by the observed catalytic abilities of soluble and mineral phosphates (Saladino et al., 2006c) on the synthetic reactions by formamide. The relevance of these observations in the search for nonterran life is discussed.     

Structure of low-head two-phase flow in flat nozzles during outflow of the liquid into rarefied medium

Outcomes of experimental researches of the low-pressure adiabatic flow of the boiling liquid through two-dimensional Laval nozzles in a vacuum atmosphere were adduced. Requirements of critical conditions of flow were determined. Structural forms of a stream were investigated and their connection with crisis of flow was shown. It was established periodic non-stationary macrostructures of a stream which was stipulated by the rotational gear of origin of a vapor phase.      

风力机叶片表面压力分布测量

本文给出了一个直径为5.35米的水平轴风力机在中国空气动力研究与发展中心12米×16米风洞试验段中进行的叶片表面压力分布的测量结果。在 Re 数从4×10~5至1.2×10~6的范围内,测量了叶片上八个剖面的压力分布。同时还用内式六分量天平测量了风轮的推力和功率。试验结果表明:风轮叶片根部处的载荷高于理论计算值,而叶尖处的载荷则低于理论计算值;叶素-动量理论对风轮最大功率预估偏低,而在高叶尖速比下,它对风轮的功率和推力预估偏高。测压试验结果与测力试验结果符合一致。     

海上舰船目标的机载高分辨率ISAR成像

本文提出了机载高分辨率二维逆合成孔径雷达(ISAR)对舰船目标的侧视成像问题。通过采用舰船运动的简单模型，避免了采用高级的联合-时间频率(JTF)变换。研究了包括运动估计与校正、最佳处理时间与持续时间估计以及目标形状提取的鲁棒处理方案。强调了这样一个事实，即该处理的鲁棒性造就了单个ISAR成像分析而不必由一组雷达图像进行数据融合。     

Shareable Instruments and Observatories for the Joint Research Center on Space Weather of the Siberian Branch of Russian Academy of Sciences and Chinese Academy of Sciences

Presented are the ideas and proposals in regards to the pooling of by RAS, SB, ISTP, and CSSAR,CAS toward coordinated usage of existing ground-based and orbiting helio-geophysical observatories, single large installations as well as creating, forecasting services and new observing facilities, in the interests of achieving a profitable activity of the China-Russia Joint Research Center on Space Weather (JRCSW).      

APC—2／AS4预浸料带热芯缠绕的显微特征

通过对ＡＰＣ－２／ＡＳ４热塑性预浸带缠绕过程的研究，分析了缠绕管件的断面显微特征，认为热塑性预浸带热芯缠绕成形过程中，形成孔隙的主要原因是层间的不良浸渍而非基体的降解。提高缠绕张力和树脂含量有利于孔隙的消除，但又对制件中树脂的均匀性及外表面尺寸稳定性有影响。     

射电干涉测量的动基应用

本文研究了与移动接收机有关的射电干涉测量误差源。结合已发表的数据,经独立研究给出了接收机噪声、时钟抖动、定时漂移、多路径误差、电离层和对流层折射效应引起的各种误差的均方根值。动基射电干涉测量系统仿真中,加进了有显著影响的统计误差模型,以评价接收机运动状态的测量精度。假设这个系统由两台配有原子钟的双频接收机组成。在记录的GPS信号相位的事后处理中,应用多普勒频移检测技术和互相关算法来确定基线距离和飞行器的运动参数。初步分析结果表明:动基射电干涉测量将提供与目前惯导技术同等的导航精度,甚至更高。     

氯丁橡胶的动态力学性能

汽车发动机前支架的功能橡胶另件需要满足与防震和消音有关的一系列物理和动态力学性能。就小型发动机而言,因为在宽频率范围内必须防震,可选择高阻尼橡胶。然而,在非常慢的速度下,高阻尼橡胶的传递性随频率降低而降低,并且某些高阻尼橡胶抗蠕变性较差。本报告(?)述新的配方工艺;用配比为87.5/12.5%的氯丁胶和丁腈胶并用胶来获得满足汽车发动机前支架所需的物理、动态力学和蠕变性能的典型技术要求。用 Rheovibron 法在广泛的温度、频率和应变范围下测量了这种共混的动态力学性能,且与其它弹性体如乙稀/丙稀酸类共混胶进行了比较。     

Identification of vortices in a transonic compressor flow and the stall process

IntroductionVortex is often the essential element re-sponsible for triggering stall and surge in com-pressors.So the identification and the analysisof the vortices in compressor are usually quitehelpful for the understanding of the compressorbehavior.Howe…