阴影区较远距离手动交会对接目标识别方法

针对阴影区较远距离手动交会对接过程中由于仪表照明灯电功率的限制所出现的摄像机无法识别目标的问题,提出增强仪表照明灯电功率、利用交会对接光学成像敏感器标志器、结合激光雷达测量数据信息、在目标上贴附主动发光材料、实施跨区域交会对接方案5种方法,有效解决了手动交会对接过程中阴影区较远距离位置的目标识别问题.该方法切实可行,可供后续型号参考.     

操作系统共享数据临界保护正确性测试方法

研究了共享数据临界保护正确性测试,提出一种基于共享数据地址监控的临界保护正确性测试方法(SVAM,Shared Variable Address Monitor).SVAM由实时地址监控模块和共享变量地址列表组成.当系统运行时,SVAM在地址总线上实时监测共享变量的写操作,当系统在更新共享变量值时没有关闭中断说明对该变量的操作破坏了临界保护,存在运行风险.理论分析证明了SVAM的正确性,仿真试验证明了该方法的有效性.      

积云对流参数化方案对东亚夏季风模拟对比

利用MM5模式对比5种不同积云对流参数化方案,即Kuo方案、Grell方案、Kain-Fritsch方案、Betts-Miller方案和赵思雄修改的Kuo方案对东亚季风区强、弱季风年夏季风的模拟能力。结果表明:5种对流参数化方案对各季节都有一定的模拟能力,各个方案对降雨的预报能力随地区和年际而有所不同,对强季风年grell和bm方案对雨带特征的描述较好,对弱季风年bm和zhao方案对雨带的模拟与实际最为接近。     

The subauroral electron density trough: Comparison between satellite observations and IRI-2007 model estimates

We compare electron density predictions of the International Reference Ionosphere (IRI-2007) model with in situ measurements of the satellites CHAMP and GRACE for the years from 2005 to 2010 over the subauroral regions. The electron density between 58° and 68° Mlat are considered. The trough region Ne peaks during local summers and attain the valley during local winter. Around −100°E and 60°E, two larger electron density sectors features can be seen in both hemispheres during all three seasons, which attributed to the electron extending from middle latitude to trough region. From 2005 to the beginning of 2010, the model overestimates the trough region Ne by 20% on average and the decrease of Ne in this region can also be seen during the last solar minimum. In the southern hemisphere, the model prediction shows quite well consistence with the observation during all three seasons while the huge difference between observations and model estimation implies that the IRI-2007 model needs significant improvement to predict better the trough region in northern hemisphere.     

Tropopause analysis over the Iranian region using GPS radio occultation data

Near-tropopause phenomena like upper level fronts and cyclones, penetrative cumulus convection and mesoscale mechanisms of exchange make important contributions to the mixing processes in the atmosphere. Spatio-temporal monitoring of the tropopause height, temperature and pressure is an appropriate tool to show the running processes in the atmosphere. In this study, GPS radio occultation data is used to investigate the tropopause height fluctuations and the relation between the stratosphere–troposphere exchange and the aforementioned phenomena over the Iranian region. The paper shows how the position of the sub-tropical jet has changed with time, using GPS radio occultation observations. The tropopause height changes latitudinally, and three different bimodal probability distribution functions are observed. The results also show that the mixing region in the south of Iran is associated with the subtropical jet in winter. However, this region shifts north of Iran due to changes in the position of the subtropical jet during the summer. Consistency of the mixing region from the radio occultation data and the total ozone of TOMS over the Iranian region is also observed.     

空间多目标拦截交会平台停泊轨道设计优化

针对空间多目标交会(拦截)平台停泊轨道设计问题,定义有效交会(拦截)区作为衡量平台交会(拦截)目标能力的指标,提出并建立了该类空间平台停泊轨道设计优化和分析模型,采用多岛遗传算法(MGA),以有效交会(拦截)区的最大化作为优化目标,以可交会(拦截)目标的数目和子飞行器轨道转移所需要的脉冲速度增量等为约束条件,对该类平台停泊轨道要素和子飞行器变轨时机进行综合设计优化。将上述模型和算法用于两空间平台设计中,一个是针对低轨2目标的交会平台,另一个是针对中轨3目标的拦截平台,得到合理的结果,表明所提出的设计优化模型以及选择的寻优算法是有效的。     

金属疲劳扩展区和瞬断区的物理数学模型

以金属的疲劳扩展区和瞬断区为对象,讨论了应力变化幅度与裂纹临界长度、疲劳寿命和临界裂纹长度的数学模型;分析了疲劳瞬断区上放射线的物理数学模型,探讨了疲劳瞬断的性质和控制参量以及疲劳瞬断区的对称性,得到了一些颇有启发性的结果,为金属材料的疲劳宏观断口定量分析提供了有价值的思路     

空面导弹命中精度最优测试评定方法

空面导弹命中精度试验结果评定方法对空面导弹的研制和使用具有显著的影响.在给定圆概率偏差的条件下,根据导弹飞行试验的数据、研制方风险、使用方风险、评定分辨率等参数,确定评定方案,给出在不考虑系统偏差时的落点检验域的划定方法以及导弹是否满足战术技术要求等评定指标.仿真实例以某一具体型号为例,验证了该方法的有效性.该方法可用于空面导弹的精度评估中.     

LES of film cooling for different jet fluids

The present paper investigates the impact of the velocity and density ratio on the turbulent mixing process in gas turbine blade film cooling.A cooling fluid is injected from an inclined pipe at α=30° into a turbulent boundary layer profile at a freestream Reynolds number of Re∞=400000.This jet-in-a-crossflow(JICF) problem is investigated using large-eddy simulations(LES).The governing equations comprise the Navier-Stokes equations plus additional transport equations for several species to simulate a non-reacting gas mixture.A variation of the density ratio is simulated by the heat-mass transfer analogy,i.e.,gases of different density are effused into an an air crossflow at a constant temperature.An efficient large-eddy simulation method for low subsonic flows based on an implicit dual time-stepping scheme combined with low Mach number preconditioning is applied.The numerical results and experimental velocity data measured using two-component particle-image velocimetry (PIV) are in excellent agreement.The results show the dynamics of the flow field in the vicinity of the jet hole,i.e.,the recirculation region and the inclination of the shear layers,to be mainly determined by the velocity ratio.However,evaluating the cooling efficiency downstream of the jet hole the mass flux ratio proves to be the dominant similarity parameter,i.e.,the density ratio between the fluids and the velocity ratio have to be considered.      

重庆大宁河特大桥成桥状态抖振响应分析

目前桥梁的抗风研究主要针对平原开阔地区,复杂山地风作用下桥梁的抗风问题研究很少。以重庆大宁河钢桁架特大拱桥为对象,通过现场实测,得到了该桥桥址处的风环境特性,包括平均风速沿高度的变化规律、湍流强度、脉动风功率谱密度函数以及湍流积分尺度等参数。根据风特性参数,计算出该桥在成桥状态下的抖振力和响应值,结果表明：即使在45m/s风速下,抖振位移响应也在公路桥梁抗风设计规范（JTG/T D60-01-2004）规定范围内。山区地貌中的平均风速沿高度的变化规律不符合公路桥梁抗风设计规范给出的指数变化率分布,湍流强度明显大于规范值。