The socioeconomic benefits of Earth science and applications research: reducing the risks and costs of natural disasters in the USA

A wealth of satellite data has provided information on weather and climate phenomena for the past 40 years. Within this period, however, the heavy human and economic costs of natural disasters have increased considerably. Using hurricanes, droughts, floods and earthquakes which occurred in the USA as examples, this article describes how Earth science can be applied to such situations to predict or mitigate their effects. The economic value of providing such information is discussed, as are the issues that can affect how successful its provision will be.     

Should elliptical galaxies be idealised as collisionless equilibria?

This review summarises several different lines of argument suggesting that one should not expect cuspy nonaxisymmetric galaxies to exist as robust, long-lived collisionless equilibria, i.e., that such objects should not be idealised as time-independent solutions to the collisionless Boltzmann equation.     

有效的库存管理

库存管理成功的关键并不是简单地减少在部件、原材料和供给方面的资金投入,而是要在对未来所需部件和非计划维修需求进行正确的预测之后做出合理的库存规划。     

Launch vehicles and the commercial uses of outer space : The underlying economic issues

This article discusses the economics of the demand for and supply of launch vehicles. Demand is derived from both commercial and governmental uses of space, while the supply of launch vehicles is determined by governmental needs which are rarely based on economic criteria alone. Multipurpose launches such as the Space Shuttle should be viewed as a national resource instead of a profit-seeking venture. Because of the mixing of government and private uses for space vehicles, traditional economic analysis provides only a starting point for policy decisions.     

X-ray,optical and UV observations of the AM Her system E2003+225

The AM Her type object E2003+225 was observed with EXOSAT, IUE and ground-based telescopes on 1983 Oct. 12. The brightness of the ultrasoft X-ray component allowed the Objective Grating Spectrometer (OGS) to be used, which gave a model-independent determination of the temperature of the blackbody spectrum. The star was observed again on 1984 July 24 by IUE with simultaneous optical spectrophotometry. The high resolution of this observation revealed complex line profiles, and a systematic velocity much smaller than previously reported. The composite energy distribution is presented.     

Radiative damping of gravity waves in the solar atmosphere

The nonlocal character of the radiation field sianificantly modifies the radiative damping of perturbations in the solar photosphere. Gravity waves are not usually considered to exist in the solar photosphere because the radiative damping time, when based on the Newtonian approximation, is too short. However, this restriction does not apply to low order gravity waves. In fact, with the inclusion of nonlocal effects, the radiative damping for low order gravity waves becomes negative for some region in the photosphere and thus acts as a driving mechanism for gravity waves there.     

PBL的应用发展与面临挑战

基于性能的后勤保障(PBL)以多种方式存在,其中包括可用率合同、持续保障和全寿命保障等.此类合同在美国、英国以及世界各地越来越普及.但在执行此类合同的过程中也会遇到一些问题和诸多的挑战,需要解决和应对.这其中最大的问题是PBL合同究竟应该有多大?军方应当如何依靠企业?     

Registration of the 12 December 2012 satellite launch by North Korea: Should UNOOSA have accepted it?

The transmittal letter from North Korea to the United Nations Office of Outer Space Affairs in January 2013 of the registration of the placement in orbit of the North Korea satellite, Bright Star 3-2, in December 2012 raised a number of interesting legal issues. Specifically, the United Nations Security Council had adopted Resolution 2087 on the 22nd of January 2013 that condemned that North Korean launch due to the use of ballistic missile technology and that the launch was in violation of two prior UN Resolutions. The status of the satellite itself was not addressed in Resolution 2087, and the question of whether the satellite should be registered by the UNOOSA was unclear. This note concludes that the UNOOSA was legally bound to register the satellite under the terms of the Outer Space Treaty and the Registration Convention.     

制造商的新角色:航空维修综合者

剥离、合并、整合将是今后几年航空维修市场的主旋律. 一些航空公司希望将工程技术和管理工作分离出去,交第三方处理.但维修供应商必须将修理、航材,后勤和管理工作集合在一起,才能为航空公司担此重任.