卫星定位系统多径实时抑制技术研究

全球卫星导航系统给交通带来极大便利。地面接收到的卫星信号存在多径,给定位导航带来不利影响。本文在前期研究多径抑制技术的基础上,为了提高多径抑制的实时性,提出了若干加快多径抑制的方案。     

Effect of Foam Cladding for Blast Mitigation： Numerical Simulation

Two numerical simulations were performed to investigate the protective effect of the foam cladding. One simulation is based on a previous experimental study, which is a ballistic pendulum with and without a foam cladding subjected to close-range blast loading. The other model is a steel beam with and without a foam cladding under blast loading. The overpressure due to the blast event can be calculated by the empirical function ConWep or by an arbitrary Lagrangian-Eulerian （ALE） coupling model. The first approach is relatively simple and widely used. The second approach can model the propagation of the blast wave in the air and the interaction between the air and the solid. It is found that the pendulum with the foam cladding always swings to a larger rotation angel compared to a bare pendulum. However, the steel beam with an appropriate foam cladding has a smaller deflection compared to the bare beam without a foam cladding. It is concluded that the protective effect of the foam cladding depends on the properties of the foam and the protected structure.     

偏振模色散对光副载波复用系统的影响及其抑制

光链路的偏振模色散效应已成为高速 /长距离的传统光时分复用系统和光副载波复用系统的严重阻碍。文章基于一阶近似 ,导出了光副载波系统中 ,偏振模色散效应引起的射频信号功率衰落的一般表达式。并且研究了几种偏振模色散抑制方法的优缺点 ,提出了一种全新的相干检测技术来提高补偿性能。     

Introduction to Enhanced Protective Film Systems

An explosive blast mitigation alternative has increased the safety of structures by using "catcher" systems.These systems " catch" or repel the failure of the window or in-fill wall protecting life and property from ballistic shards or fragments.They can be designed to be standalone in new construction and structural retrofits or used to augment structural hardening techniques.Cables,fabrics,and thin gauge sheet steel are examples of catcher systems used in the past.A new and evolving category of catcher systems are based on polymeric materials that can be used for both wall and window upgrades.These products are a proven blast mitigation concept and K&C Protective Technologies Pte Ltd (KCPT) together with Sherwin-Williams(SW) use KCPT's blast engineering capacity and SW's material engineering principles to create engineered systems for even greater in-use performance.     

我国的自然灾害与防灾减灾教育思考

中国是世界上自然灾害多发的少数国家之一,具有自然灾害种类多,发生频率高、强度大,分布广、地域差异明显等特征.近年来,我国自然灾害发生频繁,损失巨大,造成了人员的身心创伤,增加了社会不安定因素,破坏了自然资源与环境.这就从客观上要求我们要提高防灾减灾教育必要性的认识,借鉴国外先进的防灾减灾教育经验,从政府重视开始,推动防灾减灾教育普及化、经常化和法制化;从基础教育着手,把防灾减灾教育纳入国民教育体系;采取多种形式,加强对公众的防灾减灾宣传;加强防灾减灾专业人员的培训,为落实科学发展、构建和谐社会做出应有的贡献.     

沈阳城市灾害及减灾对策

沈阳城市灾害包括自然灾害和社会灾害,显性灾害和隐性灾害。自然灾害的预防需要在研究其形成规律的基础上,依靠科学地管理来完成。社会(人为)灾害的预防需要提高各阶层人士的素养,依靠完善的管理制度来实现。     

政治语篇中缓和型FTAs作为语用策略的顺应性研究

政治语篇中,为了达到一定的交际目的,缓和型FTAs是政治家们常用的语用策略,本文以Verschueren的语言顺应论为理论框架,从交际语境的四个构成因素——语言使用者、心理世界、社交世界、以及物理世界对政治语篇中选择缓和型FTAs的语用策略的动机和机制进行较为全面的综观分析,指出该选择是政治家极有意识地对各种交际语境因素不断进行动态顺应的结果。     

Distributors and film critics: does it take two to Tango?

Previous literature has documented the impact of critics on audience choices of movies. We investigate three issues regarding professional critics in the motion picture industry. First we document whether and to what extent critics and their recommendations exhibit a statistical bias toward specific studios. We show that reviews by a number of critics are significantly affected by the film distributor’s identity. A second question is whether audiences are able to distinguish between biased and unbiased critics. We cannot support the view that audiences put less weight on the views of biased critics; in fact, they may listen to them more. Third, we try to characterize critics who are more prone to bias. Surprisingly, but in accord with reputation models, we find that more reputable critics may be more biased; in particular, critics based in L.A. tend to significantly prefer specific studios.