Aerodynamics of smart flap under ground effect

Aerodynamic characteristics of two-dimensional smart flap under the ground effect have been assessed by a numerical simulation. In this process, a pressure-based implicit procedure to solve Navier–Stokes equations on a nonorthogonal mesh with collocated finite volume formulation is used. The boundedness criteria for this procedure are determined from the Normalized Variable Diagram (NVD) scheme. The procedure incorporates the k–ε eddy–viscosity turbulence model. Cantilever beam with uniformly varying load with roller support at the free end is considered for the configuration of the smart flap. The method is first validated against experimental data. Then, the algorithm is applied for turbulent aerodynamic flows around airfoil with smart and conventional flaps for different attack angle, flap angle and ground clearance where the results of two flaps are compared. The comparisons show that the quality of the solution is considerable.     

Time-dependent cosmic ray modulation

Time-dependent cosmic ray modulation is calculated over multiple solar cycles using our well established two-dimensional time-dependent modulation model. Results are compared to Voyager 1, Ulysses and IMP cosmic ray observations to establish compatibility. A time-dependence in the diffusion and drift coefficients, implicitly contained in recent expressions derived by , ,  and , is incorporated into the cosmic ray modulation model. This results in calculations which are compatible with spacecraft observations on a global scale over consecutive solar cycles. This approach compares well to the successful compound approach of Ferreira and Potgieter (2004). For both these approaches the magnetic field magnitude, variance of the field and current sheet tilt angle values observed at Earth are transported time-dependently into the outer heliosphere. However, when results are compared to observations for extreme solar maximum, the computed step-like modulation is not as pronounced as observed. This indicates that some additional merging of these structures into more pronounced modulation barriers along the way is needed.     

强光光学零件加工误差频谱分析与控制方法研究

本文利用功率谱密度分析磁流变抛光表面的敏感频率误差,发现走刀步距与中高频误差具有直接的关联性,通过小波算法确定其分布区域后,采用大束径的光顺抛光法对敏感频率误差进行控制,测试结果表明中高频误差得到了有效控制。本研究对强光光学零件加工误差的频谱分析、表征和控制具有指导意义。     

A nonlinear background removal method for seismo-ionospheric anomaly analysis under a complex solar activity scenario: A case study of the M9.0 Tohoku earthquake

A precise determination of ionospheric total electron content (TEC) anomaly variations that are likely associated with large earthquakes as observed by global positioning system (GPS) requires the elimination of the ionospheric effect from irregular solar electromagnetic radiation. In particular, revealing the seismo-ionospheric anomalies when earthquakes occurred during periods of high solar activity is of utmost importance. To overcome this constraint, a multiresolution time series processing technique based on wavelet transform applicable to global ionosphere map (GIM) TEC data was used to remove the nonlinear effect from solar radiation for the earthquake that struck Tohoku, Japan, on 11 March, 2011. As a result, it was found that the extracted TEC have a good correlation with the measured solar extreme ultraviolet flux in 26–34 nm (EUV_26–34) and the 10.7 cm solar radio flux (F_10.7). After removing the influence of solar radiation origin in GIM TEC, the analysis results show that the TEC around the forthcoming epicenter and its conjugate were significantly enhanced in the afternoon period of 8 March 2011, 3 days before the earthquake. The spatial distributions of the TEC anomalous and extreme enhancements indicate that the earthquake preparation process had brought with a TEC anomaly area of size approximately 1650 and 5700 km in the latitudinal and longitudinal directions, respectively.     

周边固支环扇形板静力学问题的小波方法

根据相关文献，将拟Shannon小波配置法应用到环扇形板的混合状态方程中，构造出了环扇形板平面方向离散，而厚度方向是解析的混合状态方程。因为用拟Shannon小波张量积表示的近似解是离散形式的，所以固支边界的未知应力可以近似地用内点的应力和位移来表示。数值实例验证了本文方法的正确性。     

空间群Pn3mPn3P23子群链耦合系数的计算

本文利用陈金全教授的本征函数法计算了Pn3m Pn3 P2 3空间群的母分系数。最后的计算结果表明 ,用陈金全教授的本征函数法所求得的母分系数确实满足幺正、归一性 ,同时也证明了本征函数法对于求母分系数同样适用     

关于“用好的作风选人，选作风好的人”的逻辑梳理

“用好的作风选人，选作风好的人”必须确定相关的概念，必须进行科学的判断，必须进行正确的推理。本文试图从逻辑角度对这一选人用人原则进行梳理。     

基于PDM的元器件库模型研究与应用

在分析国内电子企业元器件管理中存在问题的基础上,建立了基于产品数据管理的元器件库模型.重点讨论了模型中的对象模式和元器件的分类管理,提出了新元器件入库申请流程的设计.最后给出了产品设计过程中模型在元器件选用控制方面的工程实例.     

Denoising methods in interferometric SAR images processing

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求解非定常空气动力系数主导极点的近似方法

在计算与风洞实验的基础上, 提出了机翼剪切翼梢气动布局, 对平面形状与翼型进行了 优化设计, 达到了巡航状态与爬升阶段较高的增升减阻要求。计算采用涡格面元法与涡升力展向 分布吸力比拟法相结合的方法, 既能考虑气动力的非线性因素, 又有较高的计算精度与速度。计 算结果与实验数据十分吻合。通过分析得到, 在矩形翼翼梢处增加具有较大前缘后掠角的梯形剪 切翼梢有不仅增加机翼展弦比, 且可改变展向环量分布, 使其接近椭圆分布; 剪切翼梢上的前缘 涡可抑制翼端涡的作用(使翼端涡强度变弱) , 并在剪切翼梢上产生附加升力。