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11.
In the present paper the local-time variations in the disturbance of the geomagnetic-field horizontal component (H) for eight intense geomagnetic storms that occurred during the descending phase of solar cycle 23 have been analyzed. The study was based on the plot of contour lines of the H-depletion intensity in the plane local time versus universal time (LT–UT maps) with the objective of observing how the morphology and evolution of the ring current is mapped into the surface of the Earth in presence of intense geomagnetic storms.  相似文献   
12.
We present here new XMM-Newton observations of 3 relatively cool clusters at z ≈ 0.4, complemented by archival observations of 3 other clusters at similar redshift. We derived the MT and RT relations from the hydrostatic equation using an isothermal temperature distribution.  相似文献   
13.
技术是人的本质存在形式。技术范畴已发生本体论上的外延,除自然技术外,还必然涵括社会技术范畴。社会技术的存在毋庸置疑,自学界提出社会技术的概念后,社会技术与自然技术的关系便成为技术哲学研究的崭新视角。和谐技术观是社会技术与自然技术关系之基。社会技术和自然技术在消解与融合、界限、可逆性等诸方面显现出和谐图景。  相似文献   
14.
INS/SAR组合导航参数传递建模及精度分析   总被引:1,自引:0,他引:1  
 对合成孔径雷达景象匹配辅助(INS/SAR)组合导航中地面合成孔径雷达(SAR)匹配点位置参数向飞行器主惯导中心的传递过程进行研究。分析了SAR匹配点位置传递过程中所涉及的各环节及其相互关系,以此为基础建立了测量参数传递过程数学模型,提出适合该模型的误差分析与精度估计方法,结合理论和实验结果对各测量参数误差所造成的传递误差进行分析和比较,得出单一测量参数误差影响程度的排序,并在此基础上得出总精度的估计值。参数传递模型及精度实验结果与实际情况相符,可为组合导航中合理的精度分配提供依据。  相似文献   
15.
Qualitative relations between spatial regions play an importantrole in the representation and manipulation of spatial knowledge.The RCC5 and RCC8 systems of relations,used in the Region-Connection Calculus, are of fundamentalimportance. These two systems deal with ideal regions havingprecisely determined location. However,in many practical examples of spatial reasoning,regions are represented by finite approximations rather than known precisely.Approximations may be given by describing how a regionrelates to cells forming a partition of the space underconsideration. Although the RCC5 and RCC8 systems have beengeneralized to ``egg-yolk' regions, in order to modelcertain types of vagueness, their extension to regionsapproximated in this way has not been discussed before.This paper presents two methods, the syntactic and the semantic, by which the RCC5 and RCC8 systemsmay be defined for approximate regions. The syntactic uses algebraicoperations on approximate regions which generalize operations on preciseregions. The semantic method makes use of the set of preciseregions which could be the intended interpretation of anapproximate region. Relationships between these two methods arediscussed in detail.alternative to navigation training with a map.  相似文献   
16.
杨理  岳连捷  张新宇 《航空学报》2020,41(11):123701-123701
为研究斜劈诱导斜爆轰波的波阵面弯曲效应,以期为斜爆轰的不稳定性及其演化规律提供新的见解,基于加权本质无振荡(WENO)格式空间离散和附加Runge-Kutta方法时间离散的求解器,针对不同的化学反应参数(释热量、放热速率和化学反应区参考长度)条件,开展斜爆轰波的数值计算研究。结果表明斜爆轰波沿波阵面的波角变化可分为3个区域:区域I,波角平滑减小;区域II,波角跃升后衰减;区域III,波角有规律振荡。波阵面法向速度-曲率关系在区域I呈现准垂直直线变化趋势,并伴随着爆轰波强度的不断衰减;在区域III则呈现出"D"形曲线,即由极曲线段、光滑水平变化段和拟线性变化段组成,为类胞格结构的周期性演变;区域II可认为是以上两个区域特征的耦合。不同的化学反应参数对斜爆轰波波阵面的弯曲效应影响存在较大差别。  相似文献   
17.
政府职能是由政府经济职能与政府非经济职能(包括政治职能和社会职能)构成的职能体系.政府经济职能与非经济职能是政府应该履行的不同职能,两者之间存在着相同之处,也存在着不同之处;两者相互依存,相互制约.政府经济职能目标与非经济职能目标既存在协调的一面,也存在相冲突的一面.在政府要实现的职能目标中,政府优先选择的顺序是不同的,政府经济职能与非经济职能之间相互依存、相互制约的关系决定了政府职能机构体系的复杂性,也决定了政府要有效地履行其职能,就必须使政府各职能部门相互配合和协调.  相似文献   
18.
Education and public outreach (EPO) is one of the four components of the International Heliophysical Year (IHY). It is fundamental in achieving one of IHY’s primary objectives which is to “demonstrate the beauty, relevance and significance of Space and Earth science to the world.”  相似文献   
19.
Recent research in geographic information systems hasbeen concerned with the construction of algebras tomake inferences about spatial relations by embeddingspatial relations within a space in which decisionsabout compositions are derived geometrically. Wepursue an alternative approach by studying spatialrelations and their inferences in a concrete spatialscenario, a room space that contains such manipulableobjects as a box, a ball, a table, a sheet of paper,and a pen. We derive from the observed spatialproperties an algebra related to the fundamentalspatial concepts of containers and surfaces and showthat this container-surface algebra holds allproperties of Tarski's relation algebra, except forthe associativity. The crispness of the compositionscan be refined by considering the relative size of theobjects) and their roles (i.e., whether it isexplicitly known that the objects are containers orsurfaces).  相似文献   
20.
Within psycholinguistics, the dimensional conception of space is described through a variety of theoretical constructs, e.g., frames of reference, perspectives, strategies, and patterns. The objective of this paper is to introduce a uniform classification of the alternatives of dimensionally conceiving of object relations, derived from the functional and morphological asymmetries of the human body which define an anthropomorphous Origo, and from our ability to mentally project the Origo into positions and orientations other than we actually occupy. Particularly, the conception of dimensional relations on the first horizontal line is explained through the principle of perceptual accessibility of objects; this allows for the uniform treatment of (almost) all conceptual alternatives from basic psychological principles. Finally, some implications of this anthropomorphological view for the human cognition of dimensional relations are discussed and underpinned with empirical results.  相似文献   
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