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991.
航空发动机的放气活门调节规律是一个较为复杂的控制过程。依据大量QAR数据,采用数学分析的方法初步探索了PW4077D型发动机2.5级放气活门开度控制规律。通过对大量数据的统计分析可知,放气活门开度与低压转子转速N1关系最为密切。首先通过数据解码和修正得到各航班标准状态下的N1值;采用非线性回归的数理统计方法分段拟合,得到2.5级放气活门开度与N1的数学模型。经检验,该模型在一定范围内良好地反映了该型发动机2.5级放气活门开度大小的调节规律。 相似文献
992.
青年学生的德育培养是思想政治工作的一项重要而紧迫的任务,本文阐述了“八荣八耻”社会主义荣辱观对青年学生道德培养的现实意义和深远影响,以及在培养青年学生的优良品质上学校和社会的重要责任。 相似文献
993.
For maritime radiation source target tracking in particular electronic counter measures(ECM)environment,there exists two main problems which can deteriorate the tracking performance of traditional approaches.The frst problem is the poor observability of the radiation source.The second one is the measurement uncertainty which includes the uncertainty of the target appearing/disappearing and the detection uncertainty(false and missed detections).A novel approach is proposed in this paper for tracking maritime radiation source in the presence of measurement uncertainty.To solve the poor observability of maritime radiation source target,using the radiation source motion restriction,the observer altitude information is incorporated into the bearings-only tracking(BOT)method to obtain the unique target localization.Then the two uncertainties in the ECM environment are modeled by the random fnite set(RFS)theory and the Bernoulli fltering method with the observer altitude is adopted to solve the tracking problem of maritime radiation source in such context.Simulation experiments verify the validity of the proposed approach for tracking maritime radiation source,and also demonstrate the superiority of the method compared with the traditional integrated probabilistic data association(IPDA)method.The tracking performance under different conditions,particularly those involving different duration of radiation source opening and switching-off,indicates that the method to solve our problem is robust and effective. 相似文献
994.
995.
Canonical correlation analysis ( CCA ) based methods for low-resolution ( LR ) face recognition involve face images with different resolutions ( or multi-resolutions ), i.e.LR and high-resolution ( HR ) .For single-resolution face recognition , researchers have shown that utilizing spatial information is beneficial to improving the recognition accuracy , mainly because the pixels of each face are not independent but spatially correlated.However , for a multi-resolution scenario , there are no related works.Therefore , a method named spatial regularization of canonical correlation analysis ( SRCCA ) is developed for LR face recognition to improve the performance of CCA by the regularization utilizing spatial information of different resolution faces.Furthermore , the impact of LR and HR spatial regularization terms on LR face recognition is analyzed through experiments. 相似文献
996.
在虚拟仪器技术进步的过程中,由于需求的复杂性、成本的限制、技术生命期和设备寿命期等诸多因素的共同作用,新、老技术并存的情况必然存在,所以研究ATS的升级问题是一项具有现实意义和经济价值的工作.介绍了一种基于混合总线的自动测试系统升级设计,从硬件和软件两个方面详细说明了系统的实现过程.系统从硬件系统设计到软件开发都遵循了标准化和通用化的设计思想. 相似文献
997.
由于自诱导作用,椭圆涡会产生自旋运动,利用周线动力学结合涡声理论可得到理想流体中椭圆涡自旋运动辐射的远场声。在椭圆涡稳定自旋的前提下,推出了声源强度的解析表达式,并得到了数值模拟验证。研究表明:①椭圆涡的声源由两个振幅和周期相同、相位差π/2的横向四极子组成;②对横截面积和涡量相同的椭圆涡而言,其声辐射效率主要由椭圆涡的长短轴比σ决定。当σ=1时,其声辐射效率为0,即圆柱涡不辐射声;当σ≈2.618时,其声源强度最大;③椭圆涡辐射的声频率为其自旋频率的两倍。本文的方法不仅适用于σ接近于1的椭圆涡,对σ较大的稳定自旋椭圆涡也同样适用。 相似文献
998.
Magnetic Reconnection Phenomena In Interplanetary Space 总被引:3,自引:0,他引:3
Interplanetary magnetic reconnection(IMR) phenomena are explored based on the observational data with various time resolutions
from Helios, IMP-8, ISEE3, Wind, etc. We discover that the observational evidence of the magnetic reconnection may be found
in the various solar wind structures, such as at the boundary of magnetic cloud, near the current sheet, and small-scale turbulence
structures, etc. We have developed a third order accuracy upwind compact difference scheme to numerically study the magnetic
reconnection phenomena with high-magnetic Reynolds number (R
M=2000–10000) in interplanetary space. The simulated results show that the magnetic reconnection process could occur under
the typical interplanetary conditions. These obtained magnetic reconnection processes own basic characteristics of the high
R
M reconnection in interplanetary space, including multiple X-line reconnection, vortex velocity structures, filament current
systems, splitting, collapse of plasma bulk, merging and evolving of magnetic islands, and lifetime in the range from minutes
to hours, etc. These results could be helpful for further understanding the interplanetary basic physical processes.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
999.
全面评述了近年来半导体激光器应用于干涉测距的进展,对其中的代表性文献进行了详细的分析,指出了该技术今后的主要发展方向和关键问题。 相似文献
1000.
CABINNOISESOURCE-PATHIDENTIFICATIONFORAD-200ULTRALIGHTAIRCRAFTYinJianping;HuZhangwei;ZhangQiang(DepartmentofAerodynamics,Nanj... 相似文献