地源热泵技术在建筑节能中的应用

本文探讨如何通过地源热泵技术实现建筑节能。研究通过地源热泵来实现一机多用,使其既能用于冬季供暖,又可以用于夏季制冷。同时也讨论了如何与太阳能相配合,来实现地热平衡。文中还给出了通过插值法和曲线拟合法对测量数据进行处理获得变温带和增温带的温度-深度曲线的方法。     

基于准三维冰形算法的结冰预测技术及应用研究

机翼结冰是威胁民用飞机飞行安全的主要因素之一,准确预测机翼的结冰过程和特点,可为防除冰设计提供依据和支撑。提出了利用二维模拟三维的准三维冰形算法,该算法在保证结冰预测精度的同时,极大地降低了型号结冰计算成本;给出了顺气流和垂直于前缘两种典型民用飞机后掠翼机翼的二维剖面截取方法,并将采用该方法的计算结果与三维后掠机翼的结冰预测结果进行了对比分析。结果表明,相对于顺气流方式,垂直于前缘方式的准三维冰形算法与三维后掠机翼的结果更为接近。     

非对称变翼飞行器复合控制系统设计

针对非对称变翼飞行器的姿态控制问题，提出了一种复合控制系统的设计方法。基于非对称变翼的姿态动力学模型，将变翼作为一种主动控制方式，提出了非对称变翼的使用条件，并采用逻辑函数设计了气动舵和变翼的复合控制分配策略。利用扩张干扰观测器估计了变翼过程中的扰动，采用全局滑动模态的变结构控制方法，设计了姿态复合控制系统，抑制了变形过程中参数的剧烈变化和变形引起的附加扰动。通过仿真，一方面与固定翼飞行器对比，校验了非对称变翼控制的有效性；另一方面通过气动数据的正负拉偏，验证了控制器对气动参数的摄动有良好的鲁棒性。     

A Parallel Adaptive 3D MHD Scheme for Modeling Coronal and Solar Wind Plasma Flows

A parallel adaptive mesh refinement (AMR) scheme is described for solving the governing equations of ideal magnetohydrodynamics (MHD) in three space dimensions. This solution algorithm makes use of modern finite-volume numerical methodology to provide a combination of high solution accuracy and computational robustness. Efficient and scalable implementations of the method have been developed for massively parallel computer architectures and high performance achieved. Numerical results are discussed for a simplified model of the initiation and evolution of coronal mass ejections (CMEs) in the inner heliosphere. The results demonstrate the potential of this numerical tool for enhancing our understanding of coronal and solar wind plasma processes. This revised version was published online in June 2006 with corrections to the Cover Date.     

UVCS/SOHO Observations of Spectral Line Profiles in Polar Coronal Holes

Ultraviolet emission line profiles have been measured on 15-29 September 1997 for H I 1216 Å, O VI 1032, 1037 Å and Mg X 625 Å in a polar coronal hole, at heliographic heights ? (in solar radii) between 1.34 and 2.0. Observations of H I 1216 Å and the O VI doublet from January 1997 for ? = 1.5 to 3.0 are provided for comparison. Mg X 625 Å is observed to have a narrow component at ? = 1.34 which accounts for only a small fraction of the observed spectral radiance, and a broad component that exists at all observed heights. The widths of O VI broad components are only slightly larger than those for H I at ? = 1.34, but are significantly larger at ? = 1.5 and much larger for ? > 1.75. In contrast, the Mg X values are less than those of H I up to 1.75 and then increase rapidly up to at least ? = 2.0, but never reach the values of O VI.     

Composition Variations in the Solar Corona and Solar Wind

Order of magnitude variations in relative elemental abundances are observed in the solar corona and solar wind. The instruments aboard SOHO make it possible to explore these variations in detail to determine whether they arise near the solar surface or higher in the corona. A substantial enhancement of low First Ionization Potential (FIP) elements relative to high FIP elements is often seen in both the corona and the solar wind, and that must arise in the chromosphere. Several theoretical models have been put forward to account for the FIP effect, but as yet even the basic physical mechanism responsible remains an open question. Evidence for gravitational settling is also found at larger heights in quiescent streamers. The question is why the heavier elements don't settle out completely. This revised version was published online in June 2006 with corrections to the Cover Date.     

飞翼布局无人机变形机翼设计与模型验证研究

对飞翼布局无人机变形机翼和变形机翼传动机构进行了设计,根据设计结果制作验证模型进行风洞实验和外场飞行试验,以此研究伸缩段机翼对飞行器机翼整体气动性能的影响。结果表明:采用变形机翼技术,可以通过实时控制机翼的气动外形保持较高的气动效率,提高飞机在巡航状态下的升力和高速飞行状态下的机动性,满足飞机在各种任务剖面的战术性能要求。     

基于代理模型的大型民机机翼气动优化设计

先进的气动优化设计思想与方法，对于提升大型民机气动与综合性能具有至关重要的意义。探讨了大型民机超临界机翼气动优化设计的基本准则和要点，并结合代理优化算法，提出了一种面向工程应用的多轮次高效全局气动优化设计方法。首先，通过一系列解析函数/翼型/机翼优化测试算例进行了验证。其次，将所提出的方法与人工修型相结合，开展了针对宽体客机超临界机翼的两轮气动优化设计，使其气动性能得到显著改善。最后，采用不同的雷诺平均Navier-Stokes（RANS）方程求解器对安装优化机翼的全机巡航构型进行了典型状态的气动性能综合评估。研究结果表明，所提出的代理优化算法具有很高的优化效率、较强的约束处理和全局优化能力；将所发展的基于代理模型的多轮次气动优化设计方法与人工修型相结合，能够获得满足设计要求的气动外形，验证了该方法在大型民机超临界机翼气动设计中的有效性和工程实用性。     

Reconfigurable Flight Control Design for Combat Flying Wing with Multiple Control Surfaces

With control using redundant multiple control surface arrangement and large-deflection drag rudders,a combat flying wing has a higher probability for control surface failures.Therefore,its flight control system must be able to reconfigure after such failures.Considering three types of typical control surface failures(lock-in-place(LIP),loss-of-effectiveness(LOE) and float),flight control reconfiguration characteristic and capability of such aircraft types are analyzed.Because of the control surface redundancy,the aircraft using the dynamic inversion flight control law already has a control allocation block.In this paper,its flight control configuration during the above failures is achieved by modifying this block.It is shown that such a reconfigurable flight control design is valid,through numerical simulations of flight attitude control task.Results indicate that,in the circumstances of control surface failures with limited degree and the degradation of the flying quality level,a combat flying wing adopting this flight control reconfiguration approach based on control allocation could guarantee its flight safety and perform some flight combat missions.     

Solar and Solar-Wind Composition Results from the Genesis Mission

The Genesis mission returned samples of solar wind to Earth in September 2004 for ground-based analyses of solar-wind composition, particularly for isotope ratios. Substrates, consisting mostly of high-purity semiconductor materials, were exposed to the solar wind at L1 from December 2001 to April 2004. In addition to a bulk sample of the solar wind, separate samples of coronal hole (CH), interstream (IS), and coronal mass ejection material were obtained. Although many substrates were broken upon landing due to the failure to deploy the parachute, a number of results have been obtained, and most of the primary science objectives will likely be met. These objectives include He, Ne, Ar, Kr, and Xe isotope ratios in the bulk solar wind and in different solar-wind regimes, and ¹⁵N/¹⁴N and ¹⁸O/¹⁷O/¹⁶O to high precision. The greatest successes to date have been with the noble gases. Light noble gases from bulk solar wind and separate solar-wind regime samples have now been analyzed. Helium results show clear evidence of isotopic fractionation between CH and IS samples, consistent with simplistic Coulomb drag theory predictions of fractionation between the photosphere and different solar-wind regimes, though fractionation by wave heating is also a possible explanation. Neon results from closed system stepped etching of bulk metallic glass have revealed the nature of isotopic fractionation as a function of depth, which in lunar samples have for years deceptively suggested the presence of an additional, energetic component in solar wind trapped in lunar grains and meteorites. Isotope ratios of the heavy noble gases, nitrogen, and oxygen are in the process of being measured.