Aircraft PMA parts are manufactured according to the Federal Aviation Administration (FAA) design and production approval process. These parts are approved replacements for the original OEM parts. The production of aircraft PMA parts by thirdparty companies started in the US in the 1950s. In the absence of PMA manufacturers, OEMs have the monopoly over the design and manufacture of aircraft and aftermarket parts.

关键词：航空；PMA件；制造；设计和生产；批准程序；OEM部件

查看摘要 索取原文[62页]

Armored vehicles include ground combat and transportation vehicles used by landbased military forces for operations such as transporting cargo and military personnel, as well as for operating in active combats. These vehicles are protected by armor and in many cases armed with weapons. Armored vehicles provide significant strength to a country’s army and are used in large numbers by military forces around the world.

关键词：装甲车；陆基地面作战；运输车辆；活性搏斗操作；装甲保护

查看摘要 索取原文[50页]

An unmanned underwater vehicle is a small submarine used for underwater tasks. They can be divided into two categories: ROV and AUV. ROVs are usually tethered with cables, whereas AUVs operate independently and are remotely controlled. ROVs are divided into two classes: work class and eyeball. Work class ROVs are large and heavy and have the ability to lift large equipment. Eyeball ROVs are small and used in scientific exploration, inspection, observation, and rescue. AUVs are untethered and are programmed to gather oceanographic data for a set period, without any human supervision. Payloads are attached to the unmanned underwater vehicles; they help collect data and enhance the functionality of the vehicles.

关键词：无人水下航行器；小型潜艇；ROV；水下机器人；遥控潜水器；独立运作；远程控制；收集；海洋数据

查看摘要 索取原文[58页]

As part of NASA's Avionics Steering Committee's stated goal to advance the avionics discipline ahead of program and project needs, the committee initiated a multi-Center technology roadmapping activity to create a comprehensive avionics roadmap. The roadmap is intended to strategically guide avionics technology development to effectively meet future NASA missions needs. The scope of the roadmap aligns with the twelve avionics elements defined in the ASC charter, but is subdivided into the following five areas: Foundational Technology (including devices and components), Command and Data Handling, Spaceflight Instrumentation, Communication and Tracking, and Human Interfaces.

关键词：航空电子设备；指挥和控制；航天器仪表

查看摘要 索取原文[40页]

Multi-Mission Earth Entry Vehicles (MMEEVs) are blunt-body vehicles designed with the purpose of transporting payloads from outer space to the surface of the Earth. To achieve high-reliability and minimum weight, MMEEVs avoid use of limited-reliability systems, such as parachutes and retro-rockets, instead using built-in impact attenuators to absorb energy remaining at impact to meet landing loads requirements. The Multi-Mission Systems Analysis for Planetary Entry (M-SAPE) parametric design tool is used to facilitate the design of MMEEVs and develop the trade space. Testing was conducted to characterize the material properties of several candidate impact foam attenuators to enhance M-SAPE analysis. In the current effort, two different Rohacell foams were tested to determine their thermal conductivity in support of MMEEV design applications. These applications include thermal insulation during atmospheric entry, impact attenuation, and post-impact thermal insulation in support of thermal soak analysis. Results indicate that for these closed-cell foams, the effect of impact is limited on thermal conductivity due to the venting of the virgin material gas and subsequent ambient air replacement. Results also indicate that the effect of foam temperature is significant compared to data suggested by manufacturer's specifications.

关键词：航空航天器；大气层；衰减器；泡沫

查看摘要 索取原文[6页]

关键词：冻土路基；青藏铁路；水热耦合模型；数值模拟；温度分布

查看摘要 索取原文[7页]

在高速列车运行过程中,车轮踏面常因制动或空转打滑而造成局部擦伤。车轮擦伤将产生异常的轮轨冲击力,从而加剧车辆轨道结构的疲劳破坏。为调查车轮擦伤对高速轮轨接触行为的影响,建立考虑车轮擦伤的高速轮轨动力学模型,对新、旧两种车轮擦伤扁疤的几何形状及作用机理进行数值描述和动力学建模。基于动力学仿真计算,对新、旧车轮擦伤激扰下高速车辆的动力学响应进行详细调查,着重分析车轮擦伤对轮轨法向作用力及轮对垂向振动加速度的影响,并系统调查了车速、车轮擦伤扁疤深度及长度对高速轮轨冲击的影响,提出了高速车轮擦伤维修界限的计算方法。

关键词：高速列车；轮轨动力学；车轮擦伤；动力学建模；轮轨接触行为；维修界限

查看摘要 索取原文[8页]

关键词：重载列车；轮轨接触；多点接触；接触应力

查看摘要 索取原文[9页]

对高速铁路碳直接减排量、完全消耗碳减排量和完全需要碳减排量以及高速铁路碳减排量的组成进行分析计算;通过计算碳减排影响力和感应系数、行业边际完全碳减排量,分析高速铁路碳减排在整个铁路行业中的作用和影响; 采用灰色均值GM(1,1)模型,对高速铁路未来5年直接碳减排进行预测,检验模型的精度,提出碳减排弹性系数,量化高速铁路碳减排对其他行业部门和总碳减排的影响程度。结果表明,高速铁路对总碳减排的推动作用小,是最符合低碳要求的交通方式。

关键词：高速铁路；碳减排；碳减排影响力；灰色均值GM(1,1)模型；碳减排弹性系数

查看摘要 索取原文[7页]

采用一种新型的防排水结构层控制膨胀土的含水率变化,对新建云-桂高速铁路广西段的膨胀土进行整治。采用FLAC3D有限差分软件分析云-桂线中强和中弱膨胀土地段新型基床(基床中设置新型防排水结构层)在列车荷载作用下的动力响应规律,利用现场试验结果对数值分析结果进行验证,对比分析两类膨胀土地段基床动力响应规律的异同。研究表明:新型基床结构动应力、动位移、振动速度和加速度随深度的增加而减小;基床动应力的现场实测值与软件计算值规律基本一致,且大小相近,说明该数值模拟分析新型基床的动力响应规律可行;中强、中弱膨胀土地段的新型防排水结构层上下表面的动应力、剪应力存在差异,但其基床结构内的动应力、动位移、速度和加速度的衰减规律一致。本文为膨胀土地区高速铁路基床的设计、施工及其动力响应研究提供参考。

关键词：中-强膨胀土；中-弱膨胀土；新型基床结构；FLAC3D；现场试验；动应力

查看摘要 索取原文[6页]