模压石英/ 酚醛复合材料的力学和热物理性能

采用力学、热物理等测试方法,研究模压成型石英/酚醛复合材料制品性能,并与模压成型高硅氧/酚醛复合材料制品进行了对比分析。结果表明,模压石英/酚醛复合材料具有较好的力学性能,而且其线胀系数是模压高硅氧/酚醛复合材料的一半,在中低焓值、较低热流、较长烧蚀时间条件下具有很小的热变形。     

树脂基结构复合材料的研究进展

主要介绍了国内外树脂基结构复合材料及其成型工艺的发展现状,详细讨论了环氧树脂、双马来酰亚胺树脂、氰酸酯和聚酰亚胺复合材料以及模压、热压罐和RTM工艺,针对轻量化和低成本制造要求,提出了结构复合材料发展建议。     

模压工艺制备短纤维增强C/C复合材料的研究

以模压工艺为主线，综述了短纤维增强C／C复合材料的制备、工艺特点及其组织和性能；介绍了国内外不连续纤维增强C／C复合材料性能的研究现状；提出了发展我国短纤维增强C／C复合材料急需解决的技术难题。     

短纤维增强C／C复合材料模压成型工艺

本成果综合了常规及高温模压两种工艺的优点，将黏结剂沥青等混合料在模压成型的同时，随着模压温度的升高，压坯中的黏结剂沥青在模具内一并完成包裹浸渗和半碳化。采用本工艺，模压压力高（60～250MPa），最终模压温度高（550～750℃）；装备简单，模具寿命长，生产成本低；碳制品密度高达1．80g/cm^3，力学性能好。     

航天先进树脂基复合材料制造技术及其应用

主要介绍了我国航天工业领域先进树脂基复合材料的原材料(增强材料和基体树脂)、成型工艺技术(热压罐工艺、RTM工艺、缠绕成型工艺、自动铺放技术)和复合材料制品的加工装配工艺技术和应用等方面的最新进展,并讨论了我国航天先进树脂基复合材料制造技术的发展趋势。     

复合材料成型工艺中辅助材料的应用

复合材料成型工艺中辅助材料的应用沃西源（北京空间机电研究所北京１０００７６）在复合材料成型工艺过程中，要使用各种用途的辅助材料，其用量占原材料费用比例颇大，且与复合材料制品质量息息相关，现已引起有关人员高度重视。豆复合材料成型工艺用主要辅助材料种类门...     

复合材料加工工艺模糊推理方法

针对复合材料加工方法，在CAPP的基础上，总结出适于复合材料加工工艺的推理方法，即基于特征的模糊推理算法。先提取复合材料制品的特征，然后将影响复合材料加工工艺方法的因素模糊化，给出具体模糊值，得到适合的隶属函数。经过模糊推理之后得到最佳的加工方法。同时给出具体复合材料加工推理的例子对模糊化推理方法进行研究，推理结果与实际吻合较好。     

薄壁异形树脂基复合材料近净尺寸成型研究

通过对成型工艺选择、模具结构设计及工艺参数的研究,探索了薄壁异形树脂基复合材料近净尺寸成型。研究结果表明,注料式模压克服了传统模压成型装料腔狭窄不易装料的问题,实现了薄壁异形树脂基复合材料的近净尺寸成型,极大地提高了材料利用率、降低了加工难度、缩短了成型周期。     

碳／环氧复合材料防热板成型工艺

某防热隔板是用碳／环氧复合材料模压制成的，全套板由六块扇形板、三个支座、三个盖板组成，其中六块扇形板背面贴粘３０１软木。全套隔板通过了地面试验，并参加了飞行试验，本文详细地介绍了防热板的成型工艺。     

贫胶预浸料-RTM成型工艺及其复合材料力学性能研究

针对RTM成型工艺中的定型、预制问题,提出了一种新型的贫胶预浸料-RTM成型工艺。采用湿法预浸工艺制备了贫胶预浸料及正常胶含量的预浸料,对比了贫胶预浸料-RTM工艺成型的复合材料及预浸料模压工艺成型的复合材料的力学性能。实验结果表明,RTM工艺过程中,树脂的流动充模过程可以有效排除附着于贫胶预浸料中的气体,减少孔隙等缺陷出现的概率,复合材料的内部质量能够得到有效地保证。同时,力学性能测试表明,贫胶预浸料-RTM工艺成型的复合材料的层间剪切性能及冲击后压缩性能优于预浸料模压工艺成型的复合材料。     

A Unified Approach to Model-Reference Adaptive Systems Part I: Theory

A unified approach to model-reference adaptive control systems is presented. A linearized error equation for each adaptive system is derived about some operating point and converted into the standard form for plotting root loci. The contribution made here is to convert the selection of an adaptive technique and the choosing of adaptive coefficients for some desired system performance from a "mystical art" to standard control techniquess.     

Cyclotron masers and solar spike bursts

The theory of electron cyclotron maser emission and its application to solar spike bursts are reviewed. By analogy with the Earth's AKR, three sources of free energy are considered: a loss-cone anisotropy, a velocity-space hole, and a trapped distribution. The problem of how the radiation escapes through the second harmonic absorption layer is emphasized. Harmonic emission due to z mode coalescence may operate for some bursts, but the 2–5s delay between hard X-ray bursts and spike bursts suggests that some other mechanisms is required for most spike bursts. A model involving formation of a trapped distribution in low-density regions neighboring the flaring flux tube is considered.     

A Practical Distribution-Free Detection Procedure for Multiple-Range-Bin Radars

A distribution-free detection procedure for a multiplerange-bin radar is described. This procedure is based on the ranks of observations, but does not require elaborate equipment for rapidly ranking large amounts of data. Proposed equipment is described and analysis and results are given comparing this new procedure with certain practical (nondistribution-free) procedures. Comparisons with some "best" theoretical procedures are also given.     

战斗机的机敏性与超机动性（二）

3 机敏性(或称敏捷性) 3.1机敏性定义正如机动性最初才提出时的情况一样,对什么是机敏性?如何衡量它?它与飞机的作战效能有多大关系?设计战斗机时怎样来保证机敏性等方面目前还没有一个完全统一的认识。通常的说法是:机敏性是飞机的机动性和机动能力变化速率的综合评价。或者说飞机改变机动状态和转动机动平面的能力。对飞机的机敏性要求都是从如何取得空战优势的角度考虑的。例如,在战斗机1对1空战时,与空战胜负的直接有关因素为:(1)两机的相对速度、我机的角点速度     

A Kalman Filter Based Tracking Scheme with Input Estimation

Beginning with the derivation of a least squares estimator that yields an estimate of the acceleration input vector, this paper first develops a detector for sensing target maneuvers and then develops the combination of the estimator, detector, and a "simple" Kalman filter to form a tracker for maneuvering targets. Finally, some simulation results are presented. A relationship between the actual residuals, assuming target maneuvers, and the theoretical residuals of the "simple" Kalman filter that assumes no maneuvers, is first formulated. The estimator then computes a constant acceleration input vector that best fits that relationship. The result is a least squares estimator of the input vector which can be used to update the "simple" Kalman filter. Since typical targets spend considerable periods of time in the constant course and speed mode, a detector is used to guard against automatic updating of the "simple" Kalman filter. A maneuver is declared, and updating performed, only if the norm of the estimated input vector exceeds a threshold. The tracking sclheme is easy to implement and its capability is illustrated in three tracking examples.     

Photometric effects of accretion disks in long-period eclipsing binaries

Summary A multi-year photometric program on long-period eclipsing binaries has begun to uncover some properties of accretion disks in these systems. Emission and transmission properties can sometimes be found from light curve features produced by partial eclipses of the disk by the cool star, and by partial occultations of the cool star by the disk. These disks do not have the classical alpha structure. They are optically thin normal to the orbital plane, but may be geometrically thicker than purely gravitationally-stratified disks. Disk gas may be contaminated by dust particles acquired from the outer layers of the cool loser. In some systems, high states, produced by elevated mass accretion by the hot star, occur, suggesting that the mass distribution in the disk is clumpy. However mass-transfer rates are found, they lie between 10^-7 and 10^-6 solar masses per year.While this binary sample is small at the moment, some of its properties are shared with other systems. The author has five-color observations of about a dozen additional systems, which may fill out this picture more fully.     

Géodésie terrestre et géodésie par satellites

In the first part of the paper some of the most important concepts used in terrestrial and satellite geodesy are defined and discussed.

1. (A)
   The three reference surfaces: the topographic surface, the geoid and the reference ellipsoïd. The later is to be considered more as a convenient mathematical tool rather than a representation of the form of the earth.     
   
   

Ωm – Different Ways to Determine the Matter Density of the Universe

A summary of various measurements of the mean matter density in the universe, _m, is presented. Results from very different kinds of methods using various astronomical objects – from supernovae to large-scale structure – are shown. There is a remarkable preference for _m values around 0.3, but there are also some measurements that favour a higher or a smaller value.     

Effects of the interplanetary magnetic field on the auroral oval and plasmapause

Recent research into the effects of the interplanetary magnetic field (IMF) on the Earth's auroral oval and plasmapause are reviewed. While the IMF sector structure has been known for some time to produce asymmetries in polar-cap convection, recent work has shown these effects to extend into the dayside auroral oval. A restricted region of local times referred to as the convection throat is found to move to either side of the noon meridian in response to changes in the IMF B _y component.The question of the entry of solar-wind plasma into the magnetosphere continues to be a prime area of research. While it is generally felt that magnetic merging must play some significant role, evidence continues to mount that it does not occur at the subsolar magnetopause, as previously supposed, and that other driving forces for antisunward convection must occur on closed field lines. A suggestion is made that many of the seemingly conflicting observations that have been made in the region of the dayside cusps can be explained if significant distortions of closed field lines near the dayside magnetopause are allowed and if closed and open field lines coexist in the cusp, particularly near the entry layer.Effects of the IMF on the nightside auroral oval and on the plasmapause stem chiefly from the expansion of the oval to lower latitudes which is produced by southward IMF components and from the impulsive substorm phenomena that become stronger and more probable with increasingly southward IMF.Proceedings of the Symposium on Solar Terrestrial Physics held in Innsbruck, May–June 1978.     

Organic constituents of the carbonaceous chondrites

From a brief discussion of forms of meteorite carbon it is concluded that almost all the carbon in the carbonaceous chondrites is present as organic matter. Attempts to extract and identify this organic matter are then reviewed. It is shown that only 25 per cent has been extracted and only about 5 per cent chemically characterized. Of this 5 per cent most is a complex mixture of hydroxylated aromatic acids together with various hydrocarbons of the paraffin, naphthene and aromatic series. Small amounts of amino acids, sugars and fatty acids also are present. The possible chemical nature of the major fraction is discussed. It is suggested to be a mixture of high-molecular weight aromatic and hydrocarbon polymers.Possible sources of contamination of the meteorites are described and evidence indicating a general lack of organic contaminants is presented. It is concluded that most of the organic constituents are indigenous to the meteorites and are extra terrestial in origin. Synthetic processes for the compounds are mentioned and it is concluded that the organic material is probably of abiogenic origin.A brief review on studies of organized elements contained within the meteorites is presented. Difficulties of identification are discussed and photographs of some micro-structures of several carbonaceous chondrites are presented. No final conclusion about the nature of these objects is possible, but some appear to be various indigenous organic and mineral structures, while others are terrestrial contaminants.Contribution from the Chemistry Section, Space Science Division of Jet Propulsion Laboratory.