某型飞机前起落架自动收起的故障研究

从起落架收放控制原理出发，通过对系统核心附件电液换向阀性能分析，并结合故障发生时的情况，对某型飞机前起落架自动收起故障进行了分析研究。其分析结果和所提出的对策对预防此类故障的发生具有一定的指导作用。     

A training-free nose tip detection method from face range images

Nose tip detection in range images is a specific facial feature detection problem that is highly important for 3D face recognition. In this paper, we propose a nose tip detection method that has the following three characteristics. First, it does not require training and does not rely on any particular model. Second, it can deal with both frontal and non-frontal poses. Finally, it is quite fast, requiring only seconds to process an image of 100-200 pixels (in both x and y dimensions) with a MATLAB implementation. A complexity analysis shows that most of the computations involved in the proposed algorithm are simple. Thus, if implemented in hardware (such as a GPU implementation), the proposed method should be able to work in real time. We tested the proposed method extensively on synthetic image data rendered by a 3D head model and real data using FRGC v2.0 data set. Experimental results show that the proposed method is robust to many scenarios that are encountered in common face recognition applications (e.g., surveillance). A high detection rate of 99.43% was obtained on FRGC v2.0 data set. Furthermore, the proposed method can be used to coarsely estimate the roll, yaw, and pitch angles of the face pose.     

"NTN"校准技术中的"Kick-out" 脉冲的仿真研究

本文基于微波二极管取样电路,用PSPICE软件,对“NTN”校准技术中的“Kick-out”脉冲进行了仿真研究。分别研究了选通脉冲源内阻,微波二极管诸参数（管壳电容Cp,引线电感Ls,结电容Cj和扩散电阻Rs)、取样脉冲的对称性和取样电路的对称性,对“kick-out”脉冲的影响。     

电机转子硬绕组的拉形、整形和设计参数的确定

通过分析转子硬绕组制造过程中的结构特点,提出硬绕组拉形、整形工艺的技术关键和解决方案,并对绕组设计参数的确定作出准确描述,达到设计和工艺对转子硬绕组生产过程的合理、有效的控制。     

数控车削加工中刀尖圆弧半径补偿分析

车刀刀尖半径补偿是数控车削加工中的常见问题,本文重点就刀尖半径的影响及造成的加工偏差进行了分析,同时介绍了目前常用的刀尖半径补偿方法。     

Study on Theory of Cutting Edge Modeling and Helical Groove Machining of Nose Burr

ounnvCwnNoseburrsoftentakecomplexshaPewithsmalldi-mension.ThehelicalpevesofthemareusuallygroundorAnlledusingdisc-t}Petools.Duetoradiuschangingalongworkpieceandthehelicalmotionofdisc-tyPetoolalongtLhehelicalcuttingpathontheworkpiece,helicalpovemachiningisextremelycomPlex.Therearebodistinctclassesofapproachesforheli-calpovemachining,tLhedirectandinverseapproaches.Themachiningproeeedingofthedirectapproachisbasedontherigorousgeometricmedelsofworkpiece.Theinverseapproachdiscussestheprohlemofded…     

Prediction of cutting force based on machining parameters on AL7075-T6 aluminum alloy by response surface methodology in end milling

Cutting forces modeling is the basic to understand the cutting process, which should be kept in minimum to reduce tool deflection, vibration, tool wear and optimize the process parameters in order to obtain a high quality product within minimum machining time. In this paper a statistical model has been developed to predict cutting force in terms of geometrical parameters such as rake angle, nose radius of cutting tool and machining parameters such as cutting speed, cutting feed and axial depth of cut. Response surface methodology experimental design was employed for conducting experiments. The work piece material is Aluminum (Al 7075-T6) and the tool used is high speed steel end mill cutter with different tool geometry. The cutting forces are measured using three axis milling tool dynamometer. The second order mathematical model in terms of machining parameters is developed for predicting cutting forces. The adequacy of the model is checked by employing ANOVA. The direct effect of the process parameter with cutting forces are analyzed, which helps to select process parameter in order to keep cutting forces minimum, which ensures the stability of end milling process. The study observed that feed rate has the highest statistical and physical influence on cutting force.     

30%多菌灵·戊唑醇悬浮剂防治苹果轮纹病田间药效试验

30%多菌灵·戊唑醇悬浮剂防治苹果轮纹病的田间试验结果表明,于苹果轮纹病发病初期开始施药,600～800倍液连施7次,间隔7～8d,对苹果轮纹病有良好的防治效果,采收期平均防效85.56%,贮藏30d平均防效达79.76%。     

自发气调包装对辣椒贮藏品质的影响

为探究不同自发气调包装对辣椒贮藏品质的影响,以\     

再入飞行器总体参数多目标优化设计

在内部装填物参数给定的情况下,减小再入飞行器的质量和雷达截面具有重要意义。本文以再入飞行器的质量和雷达截面为目标函数进行多目标优化。本文的理论和计算方法可用于再入飞行器总体设计的方案论证阶段。