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报告分类:外文技术报告

  • 2481.采用晶种故障测试对直升机齿轮状况指标进行验证

    [汽车制造业] [2014-09-03]

    A "seeded fault test" in support of a rotorcraft condition based maintenance program (CBM), is an experiment in which a component is tested with a known fault while health monitoring data is collected. These tests are performed at operating conditions comparable to operating conditions the component would be exposed to while installed on the aircraft. Performance of seeded fault tests is one method used to provide evidence that a Health Usage Monitoring System (HUMS) can replace current maintenance practices required for aircraft airworthiness. Actual in-service experience of the HUMS detecting a component fault is another validation method. This paper will discuss a hybrid validation approach that combines in service-data with seeded fault tests. For this approach, existing in-service HUMS flight data from a naturally occurring component fault will be used to define a component seeded fault test. An example, using spiral bevel gears as the targeted component, will be presented. Since the U.S. Army has begun to develop standards for using seeded fault tests for HUMS validation, the hybrid approach will be mapped to the steps defined within their Aeronautical Design Standard Handbook for CBM. This paper will step through their defined processes, and identify additional steps that may be required when using component test rig fault tests to demonstrate helicopter CI performance. The discussion within this paper will provide the reader with a better appreciation for the challenges faced when defining a seeded fault test for HUMS validation.
    关键词:直升机的性能;飞机的可靠性;系统健康监测;混合动力系统
  • 2482.延长时间谱的方法对于解决溢流

    [信息传输、软件和信息技术服务业] [2014-09-03]

    关键词:多项式;雷诺方程;光谱;时间分辨率;混合动力车
  • 2483.8级直卡车和7类校车的制动性能改进研究

    [汽车制造业] [2014-09-03]

    A Class 7 school bus and Class 8 straight truck were tested by NHTSA VRTC to evaluate relative braking performance and stability levels of various high-output foundation brake configurations. An abbreviated FMVSS No. 121 test sequence was conducted, with additional tests being performed for research purposes. Each vehicle was tested with three brake configurations: (1) standard S-cam drums (baseline) on all wheel positions; (2) hybrid-Air-disc brakes on the steer axle and S-cam drums on the drive axles; and (3) air disc brakes on all wheel positions. The vehicles were tested at two load conditions, a Lightly Loaded Vehicle Weight (LLVW) and Gross Vehicle Weight Rating (GVWR). Each vehicle-brake-load combination met the current FMVSS No. 121 standard service brake stops on a dry surface from 60 mph. At LLVW, both vehicles exhibited reductions in stopping distance when the S-cam brakes were replaced with either hybrid or all disc configuration brakes, but the difference between the two change types was negligible at this load. However at GVWR, the benefits of disc brakes at all wheel positions were clearly seen. The disc brake configuration showed shorter stopping distances of 20 and 22 percent for the straight truck and the bus, respectively, where the hybrid brake configurations only produced stopping distances that were 10 percent shorter than S-cam brakes for both trucks.
    关键词:卡车;客车;制动器(运动避雷器);性能测试
  • 2484.基于混合聚合物的太赫兹反射研究

    [汽车制造业] [2014-09-03]

    关键词:太赫兹时域光谱;复合聚合物薄膜;光学参数
  • 2485.双马来酰亚胺/先驱体聚合物共混物的杂化材料的过渡区

    [化学原料和化学制品制造业] [2014-09-03]

    Initial steps were taken in the study of processing mixtures of a polymer and a preceramic polymer to produce a hybrid material that contains a region of gradual transformation from a polymer to a ceramic. It is thought to be a first step toward the eventual development of a hybrid that is graded from a polymer matrix composite to a ceramic matrix composite. Thermal and elemental analysis, and morphology characterization of RD-730 preceramic polymer blends, which convert to silicon carbide upon pyrolysis, and Matrimid A/B polymer (a bismaleimide), were carried out as a function of cure cycle. Cure cycles were chosen to vary the resin viscosity during processing in order to affect the amount of phase separation observed. The results were then used to associate processing parameters with the miscibility of the two resins and the likelihood of producing a hybrid with mechanical and thermal properties that fall between those of the two constituents. High RD-730 loadings were achieved without phase inversion, the glass transition (Tg) of the blended material was shown to be significantly influenced by post-cure, and thermal gradients observed.
    关键词:聚合物;复合材料;层;力学性能;形态;塑料
  • 2486.基于FSPN的传感器网络混合建模方法

    [汽车制造业] [2014-09-03]

    关键词:混合; Petri网; FSPN;状态空间爆炸
  • 2487.混合翼身增压机身和隔板的设计与优化

    [汽车制造业] [2014-09-03]

    The structural weight reduction of a pressurized Hybrid Wing-Body (HWB) fuselage is a serious challenge. Hence, research and development are presently being continued at NASA under the Environmentally Responsible Aviation (ERA) and Subsonic Fixed Wing.
    关键词:机身机翼结构;结构设计;固定机翼;复合材料结构
  • 2488.PHEV的冷启动排放管理

    [汽车制造业] [2014-09-03]

    关键词:混合动力电动车;催化剂;冷启动时;控制系统
  • 2489.以EDA为基础的充电算法用于插入式混合动力电动汽车转移电源的峰值

    [汽车制造业] [2014-09-03]

    This paper proposes a charging algorithm which is based on the Estimation of Distribution Algorithm (EDA) for Plug in Hybrid Electric Vehicle (PHEV).The proposed algorithm shifts the peak of power supply,satisfies the requested State of Charge (SoC [%]),and minimizes the charging cost.The proposed algorithm uses flexible weight for charging and upper charging limit to each PHEV to minimize the charge amount in peak time.The simulation result shows that the proposed algorithm shifts the peak of power supply in commute time zones,satisfies SoC of 93% PHEVs,and reduces charging cost by 31% compared with conventional EDA algorithm.
    关键词:混合动力汽车;智能电网;分配算法估计
  • 2490.混合存储:结合SSD和HDD的具有成本效益的高性能存储系统

    [信息传输、软件和信息技术服务业,计算机、通信和其他电子设备制造业] [2014-09-03]

    Unlike the use of DRAM for caching or buffering, certain idiosyncrasies of NAND Flash-based solid-state drives (SSDs) make their integration into existing systems non-trivial. Flash memory suffers from limits on its reliability, is an order of magnitude more expensive than the magnetic hard disk drives (HDDs), and can sometimes be as slow as the HDD (due to excessive garbage collection (GC) induced by high intensity of random writes). Given these trade-offs between HDDs and SSDs in terms of cost, performance, and lifetime, the current consensus among several storage experts is to view SSDs not as a replacement for HDD but rather as a complementary device within the high-performance storage hierarchy. We design and evaluate such a hybrid system called HybridStore to provide: (a) Hybrid-Plan: improved capacity planning technique to administrators with the overall goal of operating within cost-budgets and (b) HybridDyn: improved performance/lifetime guarantees during episodes of deviations from expected workloads through two novel mechanisms: write-regulation and fragmentation busting. As an illustrative example of HybridStores efficacy, HybridPlan is able to find the most cost-effective storage configuration for a large scale workload of Microsoft Research and suggest one MLC SSD with ten 7.2K RPM HDDs instead of fourteen 7.2K RPM HDDs only. HybridDyn is able to reduce the average response time for an enterprise scale random-write dominant workload by about 71as compared to a HDD-based system.
    关键词:数据存储系统;驱动器;配置;成本效益;混合动力车
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