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21.
离散系统仿真输出数据的统计分析 总被引:4,自引:0,他引:4
概括了分析仿真产生的数据的方法,讨论了离散系统仿真输出分析的目的以及应用统计方法的要求,对单变量情形,给出了有关估计来自终态仿真和和稳态仿真参数的技术。对多变量情形,以终态仿真为例,给出了用于分析离散系统的仿真输出的某些多变量统计技术,并提出均值向量的估计方法。 相似文献
22.
钱翼稷 《北京航空航天大学学报》1993,(1):42-51
本文直接从音速线出发计算了一个旋成体跨音速绕流超音速泡中的特征线网。提出了从音速线开拓到一条超音速线的方法,计算了无旋轴对称流的特征线网,发现其特点是不能跨越对称轴线,并对其原因作了初步的讨论。本文的计算结果可应用于物面修形。 相似文献
23.
王中兴 《中国民航学院学报》1996,(6):24-30
简要介绍了专家系统的原理及构成.分析了“设计民航维修专家系统”的过程,目前加拿大正着手研制的“先进的维修软件系统”的概况.最后提出专家系统需要解决的关键技术问题及发展情况. 相似文献
24.
Els Peeters Nieves Leticia Martín-HernáNdez Nemesio J. RodríGuez-FernáNdez Xander Tielens 《Space Science Reviews》2005,119(1-4):273-292
An overview is given of ISO results on regions of high excitation ISM and gas, i.e. HII regions, the Galactic Centre and Supernova Remnants. IR emission due to fine-structure lines, molecular hydrogen, silicates,
polycyclic aromatic hydrocarbons and dust are summarised, their diagnostic capabilities illustrated and their implications
highlighted.
Based on observations with ISO, an ESA project with instruments funded by ESA Member States (especially the PI countries:
France, Germany, The Netherlands, and the United Kingdom), and with the participation of ISAS and NASA. 相似文献
25.
介绍了逻辑分析仪部分参数测量结果的不确定度分析评定方法,评定过程及结论,可应用在对于计量标准进行相应指标的不确定度评定分析上。 相似文献
26.
The formation of planetary systems is intimately tied to the question of the evolution of the gas and solid material in the
early nebula. Current models of evolution of circumstellar disks are reviewed here with emphasis on the so-called “alpha models”
in which angular momentum is transported outward by turbulent viscosity, parameterized by an dimensionless parameter α. A
simple 1D model of protoplanetary disks that includes gas and embedded particles is used to introduce key questions on planetesimal
formation. This model includes the aerodynamic properties of solid ice and rock grains to calculate their migration and growth.
We show that the evolution of the nebula and migration and growth of its solids proceed on timescales that are generally not
much longer than the timescale necessary to fully form the star-disk system from the molecular cloud. Contrary to a widely
used approach, planet formation therefore can neither be studied in a static nebula nor in a nebula evolving from an arbitrary initial condition. We propose a simple approach to both account for sedimentation
from the molecular cloud onto the disk, disk evolution and migration of solids.
Giant planets have key roles in the history of the forming Solar System: they formed relatively early, when a significant
amount of hydrogen and helium were still present in the nebula, and have a mass that is a sizable fraction of the disk mass
at any given time. Their composition is also of interest because when compared to the solar composition, their enrichment
in elements other than hydrogen and helium is a witness of sorting processes that occured in the protosolar nebula. We review
likely scenarios capable of explaining both the presence of central dense cores in Jupiter, Saturn, Uranus and Neptune and
their global composition.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
27.
A lightning swept stroke model: A valuable tool to investigate the lightning strike to aircraft 总被引:1,自引:0,他引:1
Alain Broc Philippe Lalande Emmanuel Montreuil Jean-Patrick Moreau Alain Delannoy Anders Larsson Pierre Laroche 《Aerospace Science and Technology》2006,10(8):700-708
In the context of lightning strike on the Dassault Falcon family of aircraft, the standard zoning of Falcon 50, 900 and 2000, inferred from FAA and EUROCAE WG31 documents [US Department of Transportation, Federal Aviation Administration, Advisory Circular AC 20-53A, 1985; US Department of Transportation, Federal Aviation Administration, Advisory Circular AC 20-53B, Draft, 1991; EUROCAE WG 31, Aircraft Lightning Zoning Standard, ED-91, 1998], has been presented. Zoning proves to be quite similar between the three types of aircraft. Thanks to the feed-back on lightning strikes to Falcon, lightning traces have been observed on the fuselage for different flight conditions and aircraft. Observations are compared with the zoning performed by Dassault. A physical model, developed by ONERA, was used to simulate the sweeping of lightning on the fuselage of a Falcon 900. The results are in good agreement with the lightning traces observed on the fuselages. 相似文献
28.
构建高职数控技术应用专业课程体系的改革与实践 总被引:2,自引:0,他引:2
宋文学 《西安航空技术高等专科学校学报》2005,23(3):18-20
课程体系是衡量学校办学水平和教学质量的重要标志,是实现培养目标的基本保证。从构建课程体系前提、人才培养目标、人才培养机制、课程体系构建、课程体系改革的效果等几个方面对数控技术应用专业课程体系建设进行了探讨,初步构建了产学研结合的人才培养途径,建立了理论体系和实践体系相结合的课程体系。 相似文献
29.
本文利用自适应区域方法调节机翼后每个Trefftz平面上的计算域,使得尾涡对这个计算域边界的影响足够小,从而提高了计算的精度和时间。考虑到间断面的影响,在尾涡面上引入有旋项对流场进行计算。椭圆载荷机翼计算表明本文计算结果与经典Betz理论一致。用本文方法对某轰炸机进行了计算,计算结果已用于预计其实际飞行的尾涡面。 相似文献
30.
Parameters of expanding magnetic loops and arches and of mass flows generated by them in the corona have been computed in a 1D two-fluid approximation. Two possible trigger mechanisms of the coronal transients have been considered: (i) sudden increase of the background magnetic field strength, and (ii) heating and compression plasma inside these magnetic structures. We discuss the formation of shock waves and their dependence on dynamics and geometry of the magnetic structures. 相似文献