非线性滤波在捷联惯导系统初始对准中的应用

惯性导航系统(INS)初始对准的误差方程在本质上是非线性的,估计惯性导航初始对准误差普遍采用的做法是把失准角假设为小角度,再将误差模型线性化.但当运载体遭遇恶劣环境姿态变化剧烈时,用于估计小失准角的误差模型将不再满足初始对准的要求.为满足大失准角下惯导系统的初始对准,在建立大失准角下的非线性误差模型基础上,分别应用2种...     

Entrapment of bacteria in fluid inclusions in laboratory-grown halite

Cells of the bacterium Pseudomonas aeruginosa, which were genetically modified to produce green fluorescent protein, were entrapped in fluid inclusions in laboratory-grown halite. The bacteria were used to inoculate NaCl-saturated aqueous solutions, which were allowed to evaporate and precipitate halite. The number, size, and distribution of fluid inclusions were highly variable, but did not appear to be affected by the presence of the bacteria. Many of the inclusions in crystals from inoculated solutions contained cells in populations ranging from two to 20. Microbial attachment to crystal surfaces was neither evident nor necessary for entrapment. Cells occurred exclusively within fluid inclusions and were not present in the crystal matrix. In both the inclusions and the hypersaline solution, the cells fluoresced and twitched, which indicates that the bacteria might have remained viable after entrapment. The fluorescence continued up to 13 months after entrapment, which indicates that little degradation of the bacteria occurred over that time interval. The entrapment, fluorescence, and preservation of cells were independent of the volume of hypersaline solution used or whether the solutions were completely evaporated prior to crystal extraction. The results of this study have a wide range of implications for the long-term survival of microorganisms in fluid inclusions and their detection through petrography. The results also demonstrate the preservation potential for microbes in hypersaline fluid inclusions, which could allow cells to survive harsh conditions of space, the deep geologic past, or burial in sedimentary basins.     

Influence on photosynthesis of starlight, moonlight, planetlight, and light pollution (reflections on photosynthetically active radiation in the universe)

Photosynthesis on Earth can occur in a diversity of organisms in the photosynthetically active radiation (PAR) range of 10 nmol of photons m(-2) s(-1) to 8 mmol of photons m(-2) s(-1). Similar considerations would probably apply to photosynthetic organisms on Earth-like planets (ELPs) in the continuously habitable zone of other stars. On Earth, starlight PAR is inadequate for photosynthetically supported growth. An increase in starlight even to reach the minimum theoretical levels to allow for photosynthesis would require a universe that was approximately ten million times older, or with a ten million times greater density of stars, than is the case for the present universe. Photosynthesis on an ELP using PAR reflected from a natural satellite with the same size as our Moon, but at the Roche limit, could support a low rate of photosynthesis at full Moon. Photosynthesis on an ELP-like satellite of a Jupiter-sized planet using light reflected from the planet could be almost 1% of the rate in full sunlight on Earth when the planet was full. These potential contributions to photosynthesis require that the contribution is compared with the rate of photosynthesis driven by direct radiation from the star. Light pollution on Earth only energizes photosynthesis by organisms that are very close to the light source. However, effects of light pollution on photosynthesis can be more widespread if the photosynthetic canopy is retained for more of the year, caused by effects on photoperiodism, with implications for the influence of civilizations on photosynthesis.     

FANUC—TM系统数控铣床PLC改造中挂档问题解析

本文将介绍在PLC改造后调试中所遇到的挂档问题以及对空档部分的改造思想和解决问题的过程。     

两类空间目标的非参数姿态判别方法

在详细分析空间轨道目标窄带雷达特性的基础上,利用非参数统计学的随机游程检验理论对空间目标的稳定方式进行判别,从而实现对绕质心旋转和非旋转这两类目标的分类识别。     

转子与限位器局部与整圈碰摩试验研究

设计了储能飞轮转子与限位器碰摩试验装置,用电磁激振器激励转子,激振频率与转子—支承系统模态进动频率一致,得到了大幅度低频异步反向进动并实现碰摩。分析了碰摩力对转子运动的影响。局部碰摩转子的稳定振动表明内置式限位器能够有效地限制转子低频进动幅度,局部碰摩的特征是低频进动幅值不再增加、碰摩间断发生以及转子自转速度不变。      

二维Euler方程组的高分辨率隐式差分格式的进行计算

本文首先对标量双曲型守恒律构造了一类新的二阶隐式ＴＶＤ差分格式，再利用Ｒｏｅ方法和隐式近似因子分解法推广格式到一维、二维守恒率方程组。为减少计算工作量，推导了二Ｅｕｌｅｒ方程组隐格式的对角形式。最后，针对江南－Ⅱ并行机设计了适合盱多处理机结构特征的并行计算程序，计算翼型的跨声速流场，结果令人满意。     

求解叶轮机械三维粘性可压流的初步研究

给出了用“参数多项式方法”求解叶轮机械三维粘性可压缩流的基本思路、方程和方法，采用圆柱坐标系下的三次参数多项式。中还应用此方法以一个透平和一个压气机叶片为例计算了三维粘性流场。     

吉林陨石（H5）的冲击压缩线及其意义

在二级轻气炮动高压装置上运用电探针技术测量了具有H群球粒陨石典型代表性的吉林陨石冲击压缩线。当冲击压力>～70GPa时,吉林陨石发生相变,其高压相零压密度为4.425g/cm~3,硅酸盐部分高压相零压密度为4.068g/cm~3。吉林陨石冲击压缩性质的研究结果与地球形成的星子堆积模型(IAB铁陨石+H群球粒陨石)一致。此外,根据陨石或其类似物的冲击压缩线,用阻抗匹配原理计算了主要类型陨石中重要冲击特征形成的最小碰撞速度,揭示了陨石冲击效应形成的动力学条件与空间环境。     

蜡纸模版电化学法印制座标网格技术

一、前言在钣金毛料表面印制座标网格,来测量塑性应变的大小和分布,在国外钣金生产和钣金研究工作中,已是一项重要而常用的测试技术,它主要用于: 1.实验建立各种钣金的成形极限曲线。 2.与成形极限曲线配合解决下列实际问题: (1) 预见所设计工艺过程和模具的危险度; (2) 大致定量地研究生产中各可控因素变动对变形效果的影响,从而有目的地对它们进行调整;