HY-750开口回流低速风洞

介绍了HY 75 0风洞的结构、动力系统和测试系统的组成及特点。对风洞流场进行了校测 ,结果表明 ,风洞流场品质较好 ,主要指标优于××标准规定 ,标模实验精度也达到了标准规定的合格指标。从风洞使用情况看 ,交流变频矢量控制技术在风洞中使用是可行的 ,软件平台Labview在风洞测试系统的应用也是成功的。该风洞不仅能满足测力、测压、流场演示等教学需要 ,还将在科学研究和型号研制、实验中发挥一定作用     

用差分干涉仪测量钝锥模型周围的密度场

本文介绍了用差分干涉仪测量超声速流场中钝锥模型周围密度场的试验装置和测量结果,并同尖锥模型的测量结果进行了比较。     

仿生物态模拟型硬件理论与关键技术研究

阐述了模拟型仿生硬件的概念、基本思想与技术瓶颈，分析了基于FPTA(Field programmable transistor array)的模拟型仿生硬件的结构与电子细胞电路工作原理。给出了模拟型仿生硬件的电路编码方案、个体电路测试评估方法和进化实现过程。提出了基于单染色体自适应变异进化机制的模拟型仿生硬件进化算法。以信号放大器、半波整流器、异或门数字电路作为典型应用实例，来验证模拟型仿生硬件的进化特性，并讨论了进化算法的参数选取、染色体适应度评估问题。仿真结果表明：所提出硬件进化算法的进化速度快、成功率高，所设计的FPTA细胞阵列可以实现模拟信号放大、信号处理和数字电路逻辑功能。     

高温压力传感器冷却套温度场的有限元法计算

介绍一种高温压力传感器冷却套的结构，并用有限元法计算冷却套的温度场分布，将轴对称的冷却套半边划分为许多三角形单元，将单元内的温度离散到单元三个节点上，应用传热学理论计算出三类边界条件的参数，应用有限元法计算出各节点的温度，经过计算机数据处理，得到冷却套温度场的分布，最后，对冷却套温度进行实测，测试结果与理论计算较为接近，表明冷却套结构设计是合理的，并且用有限元法计算冷却套温度场分布是行之有效的。     

DYNAMO: a Mars upper atmosphere package for investigating solar wind interaction and escape processes, and mapping Martian fields

DYNAMO is a small multi-instrument payload aimed at characterizing current atmospheric escape, which is still poorly constrained, and improving gravity and magnetic field representations, in order to better understand the magnetic, geologic and thermal history of Mars. The internal structure and evolution of Mars is thought to have influenced climate evolution. The collapse of the primitive magnetosphere early in Mars history could have enhanced atmospheric escape and favored transition to the present arid climate. These objectives are achieved by using a low periapsis orbit. DYNAMO has been proposed in response to the AO released in February 2002 for instruments to be flown as a complementary payload onboard the CNES Orbiter to Mars (MO-07), foreseen to be launched in 2007 in the framework of the French PREMIER Mars exploration program. MO-07 orbital phase 2b (with an elliptical orbit of periapsis 170 km), and in a lesser extent 2a, offers an unprecedented opportunity to investigate by in situ probing the chemical and dynamical properties of the deep ionosphere, thermosphere, and the interaction between the atmosphere and the solar wind, and therefore the present atmospheric escape rate. Ultraviolet remote sensing is an essential complement to characterize high, tenuous, layers of the atmosphere. One Martian year of operation, with about 5,000 low passes, should allow DYNAMO to map in great detail the residual magnetic field, together with the gravity field. Additional data on the internal structure will be obtained by mapping the electric conductivity, sinergistically with the NETLANDER magnetic data. Three options have been recommended by the International Science and Technical Review Board (ISTRB), who met on July 1st and 2nd, 2002. One of them is centered on DYNAMO. The final choice, which should be made before the end of 2002, will depend on available funding resources at CNES.     

A new vortex sheet model for simulating aircraft wake vortex evolution

A new vortex sheet model was proposed for simulating aircraft wake vortex evolution.Rather than beginning with a pair of counter-rotating cylindrical vortices as in the traditional models,a lift-drag method is used to initialize a vortex sheet so that the roll-up phase is taken into account.The results of this model report a better approximation to a real situation when compared to the measurement data.The roll-up induced structures are proved to influence the far-field decay.On one hand,they lead to an early decay in the diffusion phase.On the other hand,the growth of linear instability such as elliptical instability is suppressed,resulting in a slower decay in the rapid decay phase.This work provides a simple and practicable model for simulating wake vortex evolu tion,which combines the roll-up process and the far-field phase in simulation.It is also proved that the roll-up phase should not be ignored when simulating the far-field evolution of an aircraft wake vortex pair,which indicates the necessity of this new model.     

Tetrahedral satellite formation: Geomagnetic measurements exchange and interpolation

This note presents a study of a four-satellite tetrahedral formation to collect, process, and exchange multipoint measurements of geomagnetic field in a near-polar orbit. The study is conducted as a series of numerical experiments based on simulated spacecraft orbits and corresponding geomagnetic field models output. The four satellites are assumed to move in near-circular orbits specifically chosen to maintain the tetrahedron quality. The satellites exchange their simulated magnetometers readings and the collected multipoint measurements are processed on board of any of them thus creating an instantaneous interpolated map of the geomagnetic field in the interior of the tetrahedron. Interpolation is carried out with the use of Kriging algorithms, known in geostatistics for capturing spatial correlation of the data and taking into account statistical properties of the interpolated variables. We propose a concept of a servicing formation, and analyze interpolation accuracy for different formation sizes. It is then discussed how the processed multipoint measurements can be provided as a service to other nearby satellites. Finally, we show that using the existing COTS magnetometers it is possible to obtain real-time interpolation data, which are more precise at a given point and time than a conventional onboard magnetic field model, thus ensuring better attitude determination routines performance in the serviced spacecraft.     

Blue light-dependent phosphorylations of cryptochromes are affected by magnetic fields in Arabidopsis

The blue light receptor cryptochrome that could form radical pairs after exposure to blue light was suggested to be a magnetoreceptor based on the proposition that radical pairs were involved in the magnetoreception. But the effects of magnetic fields on the function of cryptochrome are poorly understood. Phosphorylation of cryptochrome in Arabidopsis was closely associated with the function of this photoreceptor. Here, we grew Arabidopsis seedlings in a 500 μT magnetic field and a near-null magnetic field and found that the 500 μT magnetic field enhanced the blue light-dependent phosphorylations of CRY1 and CRY2, and the near-null magnetic field weakened the blue light-dependent phosphorylation of CRY2 but not CRY1. Dephosphorylations of CRY1 and CRY2 in the darkness were slowed down in the 500 μT magnetic field, whereas dephosphorylations of CRY1 and CRY2 were accelerated in the near-null magnetic field. These results suggest that magnetic field with strength higher or weaker than the local geomagnetic field affects the activated states of cryptochromes, which thus modifies the functions of cryptochromes.     

基于有限元法的电磁铁磁场的计算机定量分析

随着工程领域中对电磁铁磁场分析的计算精度要求的不断提高,要求有新的数值分析方法以适应这一需求,有限元法即是符合这一需求的分析方法。主要阐述了应用有限元法分析数字阀电磁铁问题的基本思想,并运用该方法对产品前期设计进行了精密的计算和性能预测,节省了大量的设计费用,经济可比性较高。     

一种翼身融合飞行器的失速特性研究

翼身融合（BWB）布局飞行器作为下一代商用飞机的主要构型之一，越来越受到重视。对于翼身融合飞行器的研究主要针对其巡航状态的特性，而对其失速特性的研究较少。对一种翼身融合客机构型进行风洞试验研究，采用测力试验方法对其无增升装置的构型，以及具有翼梢小翼、前缘缝翼和机身上部双吊舱的组合部件构型下的纵向特性进行研究，特别是对其失速特性的分析，并通过二维粒子图像测试技术以及油流试验对其失速过程的流动机理进行研究。结果表明，无增升装置的基本构型下，翼身融合飞行器可以保持低速飞行，而各组合构型都具有提高最大升力系数的作用。对失速过程的分析表明，随着迎角的增大，飞机表面流场分离区域从翼梢开始逐渐向翼根以及机身发展，当外翼段完全处于分离区域时，飞机并不会马上失速，因为中心体同样具有提供升力的作用，且中心体的流动分离较外翼的流动分离更晚，所以当外翼在失速迎角出现升力损失时可以通过中心体的升力进行补偿，维持其低速飞行状态，真正的失速发生在中心体出现流动分离之后。