航空情报服务人员的选拔及培训

航空情报和数据是航空器能够在世界范围内安全有效运行的基本的、支柱性的要素之一,对保证飞行安全发挥着越来越重要的作用。做好AIS从业人员的选拔和培训工作,可以让适合做AIS工作的人员加入到这个行业中来,并通过不同阶段、不同内容的培训,不断提高AIS人员的职业技能水平,提升个人发展空间,这反过来也会使AIS业务得以持续改进和提高,适应不断发展的民航运输的需要。     

Structure of the magnetopause: Observations and implications for reconnection

The Earth's magnetopause is the boundary between a hot tenuous plasma in the magnetosphere and a cooler denser plasma in the magnetosheath. Both of these plasmas contain magnetic fields whose directions are usually different but whose magnitudes are often comparable. Efforts to understand the structure of the magnetosphere have been hampered by the variability and complexity of this boundary. Waves on the magnetopause surface propagate toward the magnetotail and produce the multiple boundary crossings frequently seen by spacecraft. Boundary velocities are poorly known and range anywhere within an order of magnitude of 10 km s^–1. Typical thicknesses are probably on the order of a few hundred km which is a few times the gyroradius of a thermal proton. Although conclusive direct evidence for a field component, B _n , across the magnetopause has not been found, this lack of evidence may reflect the difficulty in determining B _n in the presence of magnetopause waves rather than the real absence of this component. Considerable indirect evidence exists for an open magnetosphere, but the importance of the reconnection process thought to produce open field lines has recently been questioned.Proceedings of the Symposium on Solar Terrestrial Physics held in Innsbruck, May–June 1978.     

飞机制造企业PDM的组织和实施

分析了飞机制造企业PDM实施的需求, 对PDM实施中的产品数据管理和构型管理作了探讨, 并提出了实施目标和实施方案。     

面向MBD模型的工艺信息组织与重构系统

针对生产准备过程中人工逐项查看、查找MBD模型中产品制造信息工作量大、耗时长的问题,基于MBD模型中工艺信息的存储规范,对非几何信息的检索、提取、分析、重构技术进行了研究,在此基础上开发了面向MBD模型的工艺信息组织与重构系统,满足了制造过程中不同阶段、不同角色、不同专业对产品数模信息不同层次的使用需求。     

机械产品数字化定义的数据内容及其组织

机械产品采用计算机辅助设计后 ,以产品的数字化定义替代传统的蓝图 ,将面临着产品数字化定义的数据应该包括哪些内容、它的结构及其如何组织等一系列问题。本文对此作了较详细的论述。     

虚拟产品开发管理中的权限与组织建模

提出了一种可操作的支持虚拟产品开发管理的权限与组织模型。通过分析数据对象和组织管理中的权限水平、权限分类、数据状态以及动作方法等概念,提出了面向对象和分层次的安全权限授权管理策略。对与权限有关联的产品生命周期管理、组织建模以及开发过程等关键问题进行了探讨,给出了相应的解决方案,形成了支持虚拟产品开发管理的面向产品生命周期的数据安全以及组织管理的可行操作模型。     

Composition of anomalous cosmic rays and implications for the heliosphere

We use energy spectra of anomalous cosmic rays (ACRs) measured with the Cosmic Ray instrument on the Voyager 1 and 2 spacecraft during the period 1994/157-313 to determine several parameters of interest to heliospheric studies. We estimate that the strength of the solar wind termination shock is 2.42 (–0.08, +0.04). We determine the composition of ACRs by estimating their differential energy spectra at the shock and find the following abundance ratios: H/He = 5.6 (–0.5, ⁺0.6), C/He = 0.00048 ± 0.00011, N/He = 0.011 ± 0.001, O/He = 0.075 ± 0.006, and Ne/He = 0.0050 ± 0.0004. We correlate our observations with those of pickup ions to deduce that the long-term ionization rate of neutral nitrogen at 1 AU is 8.3 × 10^–7 s^–1 and that the charge-exchange cross section for neutral N and solar wind protons is 1.0 × 10^–15 cm² at 1.1 keV. We estimate that the neutral C/He ratio in the outer heliosphere is 1.8(–0.7, +0.9) × 10^–5. We also find that heavy ions are preferentially injected into the acceleration process at the termination shock.     

维修单位规章标准整合初探

航空器维修是民航事业的重要组成部分,各维修单位一般是根据自身的业务、经济和人文状况形成适合自己的管理体系.     

The Contributions of Comets to Planets, Atmospheres, and Life: Insights from Cassini-Huygens, Galileo, Giotto, and Inner Planet Missions

Comets belong to a group of small bodies generally known as icy planetesimals. Today the most primitive icy planetesimals are the Kuiper Belt objects (KBOs) occupying a roughly planar domain beyond Neptune. KBOs may be scattered inward, allowing them to collide with planets. Others may move outward, some all the way into the Oort cloud. This is a spherical distribution of comet nuclei at a mean distance of ～50,000 AU. These nuclei are occasionally perturbed into orbits that intersect the paths of the planets, again allowing collisions. The composition of the atmosphere of Jupiter—and thus possibly all outer planets—shows the effects of massive early contributions from extremely primitive icy bodies that must have been close relatives of the KBOs. Titan may itself have a composition similar to that of Oort cloud comets. The origin and early evolution of its atmosphere invites comparison with that of the early Earth. Impacts of comets must have brought water and other volatile compounds to the Earth and the other inner planets, contributing to the reservoir of key ingredients for the origin of life. The magnitude of these contributions remains unknown but should be accessible to measurements by instruments on spacecraft.     

Ghost Ships: Hamilton and Scourge, Historical Treasures from the War of 1812

HAMILTON and SCOURGE are two armed merchant schooners from the War of 1812 on Lake Ontario. Capsized in a squall on August 8, 1813, they lie 300 feet deep, 1,500 feet apart, 6 miles off present-day Port Dalhousie, Ontario. They are world-class archaeological treasures: intact, with all their artifacts in and around them, and perfectly preserved. They belong to the City of Hamilton, Ontario, where an international-level museum will be constructed. A major archaeological dive is planned for April/May, 1987. The HAMILTON-SCOURGE team is now involved in a research project related to merchant activity on Lake Ontario, 1800-1812. It is hoped that this will result in finding the vessels' plans or offsets, if these still exist. Many fascinating historical details have been uncovered, some of which are recounted here.     

The Global System: Conditions for Peace, Stability, and Social Justice

Achievement of peace, stability, and social justice on a global scale are seen to require fundamental whole-system change. At the deepest level this involves change in the basic premises underlying modern industrial society. Forces that could bring about such a fundamental change are evident. Appropriate use of new understandings of the power of inner imagery and affirmation could help keep the change from being as disruptive and as generative of human misery as have been some such changes in the past. James Miller has identified some of the ubiquitous characteristics of ``Living Systems', including human societies [1]. Maxwell Maltz, in writing about ``Psychocybernetics', has used a simple systems analogue to explain the power of affirmation (``self-fulfilling belief') to heal and to achieve other goals [2]. Gary Schwartz has proposed a multi-level systems model for understanding the power of inner imagery to contribute to healing of the human body [3]. Gregory Bateson includes the concept of ``a larger mind of which the individual mind is only a subsystem...(that) is immanent in the total interconnected social system and includes the planetary ecology' [4]. The following paper extends these concepts to explore conditions for healing the planet and achieving a ``cooperative security system' [5]. One of the most significant characteristics in understanding the behavior of social systems is the presence of feedback.     

Performance analysis for DOA estimation algorithms: unification,simplification, and observations

Subspace based direction-of-arrival (DOA) estimation has motivated many performance studies, but limitations such as the assumption of an infinite amount of data and analysis of individual algorithms generally exist in these performance studies. The authors have previously proposed a unified performance analysis based on a finite amount of data and achieved a tractable expression for the mean-squared DOA estimation error for the multiple signal classification (MUSIC). Min-Norm, estimation of signal parameters using rotational invariance techniques (ESPRIT), and state-space realization algorithms. However, this expression uses the singular values and vectors of a data matrix, which are obtained by the highly nonlinear transformation of the singular value decomposition (SVD). Thus the effects of the original data parameters such as numbers of sensors and snapshots, source coherence and separations were not explicitly analyzed. The authors unify and simplify this previous result and derive a unified expression based on the original data parameters. They analytically observe the effects of these parameters on the estimation error     

格柏科技:航空业精确可靠、节省与舒适的合作伙伴

<正>航空业要求精确可靠、节省与舒适齐备,而在软性材料和复合材料加工领域,有着40多年成功经验的格柏科技则是满足这样高要求的系统解决方案的代名词,包括波音、达索、西飞、沈飞等数十家航空制造企业均     

An embedded piezoelectric actuator for active vibration control:Concept,modeling,simulation,and investigation

Piezoelectric active vibration control holds paramount importance in space structures.An embedded piezoelectric actuator with a sandwich configuration is proposed,which enhances control accuracy by integrating various components.Firstly,the electromechanical coupling characteristics of the actuator are revealed,and the model is established.Secondly,the equivalent model of a cylindrical cantilever beam is investigated as the object,and the feasibility of the vibration control of the actuator is verified by simulation.Finally,the prototype comprised of two actuators,which respectively use the proposed embedded actuators for producing the vibration and suppressing the vibration,is developed,and the measurement system is constructed.Experimental results demonstrate the excellent control efficiency in two orthogonal directions,achieving a minimum vibration amplitude control of 0.001 02 mm and a maximum vibration control of-42.74 d B.The integrated structure offers fast response,lightness,adaptability,and high control efficiency,which is conducive to enhancing the vibration control.     

Magnetic Reconnection for Coronal Conditions: Reconnection Rates, Secondary Islands and Onset

Magnetic reconnection may play an important role in heating the corona through a release of magnetic energy. An understanding of how reconnection proceeds can contribute to explaining the observed behavior. Here, recent theoretical work on magnetic reconnection for coronal conditions is reviewed. Topics include the rate that collisionless (Hall) reconnection proceeds, the conditions under which Hall reconnection begins, and the effect of secondary islands (plasmoids) both on the scaling and properties of collisional (Sweet-Parker) reconnection and on the onset of Hall reconnection. Applications to magnetic energy storage and release in the corona are discussed.     

Characteristics of shocks in the solar corona,as inferred from radio,optical, and theoretical investigations

Solar radio bursts of spectral type II provide one of the chief diagnostics for the propagation of shocks through the solar corona. Radio data on the shocks are compared with computer models for propagation of fast-mode MHD shocks through the solar corona. Data on coronal shocks and high-velocity ejecta from solar flares are then discussed in terms of a general model consisting of three main velocity regimes.An invited paper presented at STIP Workshop on Shock Waves in the Solar Corona and Interplanetary Space, 15–19 June, 1980, Smolenice, Czechoslovakia.     

Arnab Rai Choudhuri,The Physics of Fluids and Plasmas: An Introduction for Astrophysicists

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