关于油滴实验几个问题的探讨

主要介绍了密立根油滴实验中影响油滴亮度的因素、解决方法；油滴的选择标准及调整方法，实验证明效果很好。     

Modeling Multifractality of the Solar Wind

The question of multifractality is of great importance because it allows us to investigate interplanetary hydromagnetic turbulence. The multifractal spectrum has been investigated with Voyager (magnetic field) data in the outer heliosphere and with Helios (plasma) data in the inner heliosphere. We use the Grassberger and Procaccia method that allows calculation of the generalized dimensions of the solar wind attractor in the phase space directly from the cleaned experimental signal. We analyze time series of plasma parameters of the low-speed streams of the solar wind measured in situ by Helios in the inner heliosphere. The resulting spectrum of dimensions shows a multifractal structure of the solar wind attractor. In order to quantify that multifractality, we use a simple analytical model of the dynamical system. Namely, we consider the generalized self-similar baker’s map with two parameters describing uniform compression and natural invariant measure on the attractor of the system. The action of this map exhibits stretching and folding properties leading to sensitive dependence on initial conditions. The obtained solar wind singularity spectrum is consistent with that for the multifractal measure on the weighted baker’s map.     

A Class of TVD Type Combined Numerical Scheme for MHD Equations With a Survey About Numerical Methods in Solar Wind Simulations

It has been believed that three-dimensional, numerical, magnetohydrodynamic (MHD) modelling must play a crucial role in a seamless forecasting system. This system refers to space weather originating on the sun; propagation of disturbances through the solar wind and interplanetary magnetic field (IMF), and thence, transmission into the magnetosphere, ionosphere, and thermosphere. This role comes as no surprise to numerical modelers that participate in the numerical modelling of atmospheric environments as well as the meteorological conditions at Earth. Space scientists have paid great attention to operational numerical space weather prediction models. To this purpose practical progress has been made in the past years. Here first is reviewed the progress of the numerical methods in solar wind modelling. Then, based on our discussion, a new numerical scheme of total variation diminishing (TVD) type for magnetohydrodynamic equations in spherical coordinates is proposed by taking into account convergence, stability and resolution. This new MHD model is established by solving the fluid equations of MHD system with a modified Lax-Friedrichs scheme and the magnetic induction equations with MacCormack II scheme for the purpose of developing a combined scheme of quick convergence as well as of TVD property. To verify the validation of the scheme, the propagation of one-dimensional MHD fast and slow shock problem is discussed with the numerical results conforming to the existing results obtained by the piece-wise parabolic method (PPM). Finally, some conclusions are made. This revised version was published online in August 2006 with corrections to the Cover Date.     

直升机旋翼标准桨叶的选定原则与方法研究

本文对直升机桨叶单片互换的原理进行了论述，对标准桨叶的确定原则以及实施方法进行了探讨，并结合直11型机标准桨叶选定工作的流程和结果，对所述方法进行了实例分析。     

Properties of Interplanetary Coronal Mass Ejections

Interplanetary coronal mass ejections (ICMEs) originating from closed field regions on the Sun are the most energetic phenomenon in the heliosphere. They cause intense geomagnetic storms and drive fast mode shocks that accelerate charged particles. ICMEs are the interplanetary manifestations of CMEs typically remote-sensed by coronagraphs. This paper summarizes the observational properties of ICMEs with reference to the ordinary solar wind and the progenitor CMEs.     

Identification of a 2D turbulent wind spectrum

Turbulent wind spectrum models usually involve nonrational terms. For such models the development of a Markovian time simulator relies on a rational approximation obtained by the way of an identification stage. This paper presents a general method to manage this identification stage, that provides us with a family of stable rational approximations which is proved to converge towards the true model as the dimension increases. We first give an exact but infinite dimensional state space representation of the spectrum. It is based on the use of a diffusive equation. For bi-dimensional (2D) signals it also uses decoupling by spatial Fourier transformation. Then the discretization of this exact model leads easily to stable finite dimensional approximations over a prescribed frequency range. This approach is applied to the identification of a theoretical 2D turbulent wind spectrum, and of a 1D turbulent wind spectrum estimated from in flight recorded data.     

先进战斗机气动弹性设计综述

中国新一代战斗机的研发引领了飞机设计领域各项技术的创新和发展。针对研制总要求和任务特殊性，中国航空工业成都飞机设计研究所气动弹性专业建立了精益气动弹性设计与验证技术体系。基于多学科优化设计流程，开展了旨在提高飞机气动弹性品质的关键技术攻关、气弹优化设计和分析工作。完成了考虑含全动翼面结构非线性的全机动力学特性地面试验、亚跨超声速颤振模型风洞试验和气动弹性飞行试验验证。在较短的研发周期内，成功实现气动弹性设计目标，为新一代战斗机的成功研制提供了技术保障。描述了该飞机气动弹性设计历程、主要技术工作以及在此基础上取得的技术进步、能力提升以及具有研究所特色的气动弹性设计知识工程建设。     

巨型晶闸管在大型直流电动机拖动中的应用

巨型晶闸管在国内首次成功地用于大型风洞的动力系统──大型直流电动机拖动系统中，使大型直流拖动的控制系统简化，１０００—３０００ｋＷ系统简化到一个三相全控桥式整流电路，或两个三相全控桥式整流电路并联输出的技术问题上，而且由于系统简单化，潜在的故障因素减少，可靠性增强，维护的工作量也大大减少。本文介绍风洞动力控制系统的实用调速方法，以及用计算机控制速压的方法。     

模拟中性大气边界层中污染物传输与扩散的动力相似讨论

文章从湍流雷诺数相等出发,推导出风洞中模拟中性大气边界层动力相似准则一充分发展的湍流中,运动相似的流动动力也相似。文章还讨论了模拟烟流抬升和扩散的相似准则,概述了国内外一些主要实验室应用的近似模拟技术。     

南航立式水洞实验技术及应用

本文介绍了南航270mm×270mm立式水洞,对水洞流态显示技术中较为关键的几个问题:如试验模型设计,彩色染色液体配方,灯光与摄影技术等进行了简述,并对其实际应用提供了几个示例,以供参考。