一种组件化的无人机机动模型设计与实现

在联合作战背景下,无人机已然是不可或缺的作战力量,因此,在基于联合作战的仿真系统中,研究并建立无人机模型是当前的工作重点。针对无人机空中机动行为的建模需求,采用组件化建模的方法,设计并构建了固定翼的无人机机动模型,初步实现了无人机的空中机动行为,最后通过仿真推演,验证了模型的可用性与合理性。

土质斜坡存在唯一最小安全系数的数据作图论证及原因分析

本文通过数据作图法揭示了土体黏聚力和内摩擦角对斜坡安全系数作用的不同规律,并论证了一般土质斜坡存在唯一最小安全系数及其原因。本文在土质斜坡中划分了大量的潜在滑移面,并定义了每一个潜在滑移面所拥有的4类安全系数FOS^(c×φ)、FOS^(c)、FOS^(φ)和FOS^(c+φ)。基于极限平衡的条分法计算了滑移面的4类安全系数,并使用数据作图法揭示和确定了这4类安全系数值随潜在滑移面深度d变化的4条特征和规律。由土体黏聚力和内摩擦角共同作用的安全系数FOS^(c×φ)包络线随d的增加先单调下降,到达一段最小值区间后,再单调上升。因此,它必然存在一个总体最小值。仅由土体黏聚力贡献的FOS^(c)包络线随d的增加先快速、再缓慢单调下降。仅由土体内摩擦角贡献的安全系数FOS^(φ)包络线随d的增加线性上升。FOS^(c)与FOS^(φ)之和FOS^(c+φ)数值几乎等同于FOS^(c×φ)数值。这4条规律揭示了土体黏聚力和内摩擦角对斜坡安全系数作用的不同规律,并论证了一般斜坡存在最小安全系数及其原因。本文进一步论证和揭示了这4条特征和规律适用于5种经典有限条分法的计算结果,适用于考虑地下孔隙水压强作用的计算结果,和考虑斜坡土体分层不均质影响的计算结果。特别地,地下孔隙水会加深拥有最小安全系数的潜在滑移面深度。土体黏聚力对斜坡安全系数贡献随潜在滑移面深度增大而减小,土体内摩擦角对斜坡安全系数贡献随潜在滑移面深度增大而增大。这两种强度随深度的相反贡献规律导致了一般土质斜坡存在唯一最小安全系数。

基于分片式数据帧的态势监控和回放系统的设计与实现

在装甲兵训练中,使用模拟器模拟实车组织训练是一种应用广泛且有效的训练手段。当前的装甲模拟训练系统存在训练资源利用不充分,训练过程回放实时性差等问题,从提高训练效率入手,提出了一种新的分片式数据结构,支持多个训练任务同时进行并切换到指定任务进行监控,同时满足态势回放需要点播和后退的需求。利用推算定位(dead reckoning,DR)技术降低了训练过程产生的数据包,支持大规模节点组网并同时进行训练。基于Unity3D引擎开发了态势监控和态势回放系统,并搭建综合仿真验证环境。仿真结果表明,该系统能够满足指挥员同时组织多席位训练,对训练过程进行实时指导、以及训练回看的需求,提高了训练效率。

陕西省近30年潜在蒸发量的时空变异规律

根据陕西省34个代表气象站点1988年—2017年逐日气象数据,分析以Penman公式计算的潜在蒸发量的时空变异规律及其对湿润指数的影响。结果表明:陕西省1988年—2017年平均的潜在蒸发量959 mm,从陕北(1020 mm)、关中(967 mm)到陕南(899 mm)逐渐降低,其差异主要在于空气动力学项。陕北潜在蒸发显著增大(25.9 mm/10 a),而关中和陕南潜在蒸发变化的趋势值分别只有12.2 mm/10 a和6.5 mm/10 a,相对湿度减小和风速增大引起的空气动力学项的增大(16 mm/10 a)是陕北潜在蒸发量显著增大的主要原因。受潜在蒸发变化影响,陕北和关中地表湿润指数增大但大气湿润指数减小,反映出两类不同过程的影响。

Tidal flat erosion of the Huanghe River Delta due to local changes in hydrodynamic conditions

An ideal nature system for the study of post-depositional submarine mass changing under wave loading was selected in the intertidal platform of the subaqueous Huanghe River Delta, a delta formed during period from 1964 to 1976 as the Huanghe River discharged into the Bohai Gulf by Diaokou distributary. A road embankment constructed for petroleum recovery on the inter-tidal platform in 1995 induced the essential varieties of hydrodynamic conditions on the both sides of the road. With both sides sharing similarities in （1） initial sedimentary environment, （2） energetic wave loading, （3） differential hydrodynamic conditions in later stages, （4） enough long-range action, and （5） extreme shallow water inter-tidal platforms; the study is representative and feasible as well. Two study sites were selected on each side of the road, and a series of measurements, samplings, laboratory experiments have been carried out, including morphometry, hydrodynamic conditions, sediment properties, granularity composition, and fractal dimension calculation of the topography in the two adjacent areas. It was observed that in the outer zone, where wave loading with high magnitude prevailed, the tidal flat was bumpy and exhibited a high erosion rate and high fractal dimension. Further, the fractal dimension diminished quickly, keeping with the enlarging of calculative square size. However in the inner zone, where the hydrodynamic condition was weak, the tidal fiat was fiat and exhibited a low erosion rate and low fractal dimensions; the fractal dimension diminished with the enlarging of calcu- lative square size. The fractal dimensions in the different hydrodynamic areas equalized increasingly as the calculative square size accreted to threshold, indicating that the hydrodynamic condition plays a significant role in topography construction and submarine delta erosion process. Additionally, the later differentiation of sediment properties, granularity composition, microstructure characteristics, and mineral composition induced by the different hydrodynamic conditions can also contribute to the variation of topography and sea-bed erosion in the two adjacent areas.

GPS/Galileo实时天顶对流层延迟估计研究

采用14个MGEX测站观测数据,利用实时PPP估计方法计算得到Galileo、GPS和GPS/Galileo组合ZTD估值。14个测站的Galileo和GPSZTD估值的相关系数绝大多数大于0.9,且Galileo-GPSZTD差值的RMS为8~16mm,RMS的平均值为12.3mm,证明Galileo和GPS解的符合性良好,Galileo实时估计的ZTD精度满足要求。同时,IGS最终ZTD产品被用来评价各解算结果的精度,结果显示,GPS/Galileo联合解算时,相对于GPS单系统精度提高了5%~35%,相对于Galileo单系统精度提高了25%~51%。

条件介词短语的变体类别及其功能

由介词或介词框架标记的条件题元,存在着“限制条件”“适时条件”和“倚变条件”三种变体。限制条件有表述具体行为事件和抽象事件之别,分别具有[+行为事件]和[+图像事件]的语义特征,用以规约述谓事件出现的背景;适时条件具有[+状态]和[+时点]的语义特征,用以表述述谓事件发生的适宜时机;倚变条件具有[+变化]和[+事件]的语义特征,它是述谓事件发生或变化的依据和参照体。正是这些不同的条件题元变体,决定了不同条件介词短语蕴涵句的语义功能的差别。

Waterproof of rock joint with lead strip for splitting tuff sheet in ancient China quarrying caverns

This paper presents the relics of rock joints caulked with lead strips, unearthed by the authors in 2007 and 2008. The relics were in ancient quarry caverns in Shepan Island, Zhejiang Province, eastern China. The quarry activities were mainly carried out for production of regular tuff stone plates about 800 years ago. Each of the lead strips was sealed into a rock joint by punching manually and carefully. At present, the lead strips still contact tightly with the rock joints and new mineral cerussite is found to have formed at the contact surfaces between the lead strip and its caulked rock joint. The use of lead strips caulking rock joints in quarry caverns is found for prevention of water from seeping out of the country rocks into quarry cavern bases, where all of the in-situ intact tuff rock was manually and near-horizontally split into thin rock sheets one by one for production of regular tuff plates. Furthermore, it is found that the tensile splitting of tuff sheets at the cavern base required the intact rocks at the cavern base had to be dry. Through this horizontal base splitting for tuff sheets from the top to the bottom, a dome-shape interior space was formed for each rock cavern with the near horizontal imprints of thin sheet layers permanently on the sidewalls.