高原环境下增压器压气机叶轮轮毂疲劳可靠性研究

针对涡轮增压器压气机叶轮在高原地区工作时潜在的轮毂疲劳失效模式,研究了高原环境下涡轮增压器转速的变化规律以及压气机叶轮轮毂疲劳失效危险部位的应力。在此基础上,建立了增压器压气机叶轮的轮毂疲劳可靠度计算模型,分析了增压器压气机叶轮轮毂疲劳可靠度随不同海拔高度的变化规律。研究表明,当发动机在高海拔地区工作时,涡轮增压器压气机叶轮发生轮毂疲劳失效的风险在增大,随着海拔高度的增加,压气机叶轮轮毂的疲劳可靠性在降低。     

对新媒体环境下把握高校突发事件舆论主导权的因素与路径分析

当前,我国正处在经济社会剧烈转型的多元时代,矛盾问题集中凸显,突发事件易发高发,特别是在新媒体环境下,舆情应对任务日益艰巨繁重。高校作为大量人群集中和文化社会群体的特殊性,很容易引发突发事件,并成为社会媒介炒作的题材和人们关注的焦点,处置不当必然将严重影响学校和社会的安全稳定。     

大数据环境下的城市交通综合评估技术

伴随城市蔓延、轨道交通成网、用地开发等发展条件,大城市综合交通环境日益复杂。如何拓展评估边界、深化评估技术、提升评估频率和延伸评估视角成为传统城市交通评估技术体系面临的四个关键问题。首先介绍交通领域大数据的组成、特征及应用情况。通过深度挖掘交通运行产生的多源异构数据,建立集统计、关联、预测于一体的交通大数据分析平台和专题评估子系统,形成面向多层次、多领域应用需求的一体化综合交通模型体系。最后,基于深圳市的应用实践情况,阐述城市交通综合评估技术从城市到区域、从宏观到微观、从静态到动态、从土地到环境的转变。     

级环境下叶片表面粗糙度对压气机气动性能的影响

采用数值方法,在压气机级环境下研究了叶片表面粗糙度对压气机内部流场及特性参数的影响.结果表明,叶片粗糙度对压气机的主要性能参数影响明显;随着叶片粗糙度的增大,压气机级性能衰减加剧,叶轮叶片表面粗糙度增加到100μm以上时,在近失速工况下压气机的总压比和等熵效率下降达10%以上,压气机内气流能量损失增大,尤其是靠近叶轮前缘中上部的气流能量损失严重,同时引起叶片端壁温度升高.     

小水线面双体船抗冲击特性数值研究

文章介绍了小水线面双体船型的特点,阐述其在军事领域的应用和发展前景。运用数值仿真方法计算水下非接触爆炸作用下小水线面双体船的结构变形和冲击环境,分析此船型结构抗冲击特性和全船冲击环境特点,提出在抗冲击设计时的重点设计区域和优化方向,为其军事应用提供技术积累。     

深圳咪表停车管理的研究与对策

1995年深圳从香港引进咪表对道路停车进行管理,使得深圳的道路停车问题得到了较好的解决,交通环境得到了很大改善。但同时,咪表停车管理与体制上的种种矛盾也逐渐显现出来,并最终导致咪表在深圳暂停使用。该文从政策、交通环境等外部因素和咪表管理的自身因素上对咪表在深圳的实施进行分析,探索其在外部政策环境上和咪表停车管理实施上存在的不足和弊端,挖掘咪表在深圳实施失败的深层次原因,并提出了改进建议。     

Preoperational ocean forecasting in the southeastern Mediterranean Sea: Implementation and evaluation of the models and selection of the atmospheric forcing

Within the framework of several local and international programs, a quasi-operational ocean-forecasting system for the Southeastern Mediterranean Sea has been established and evaluated through a series of preoperational tests. The Princeton Ocean Model (POM) is used for simulating and predicting the hydrodynamics while the Wave Model (WAM) is used for predicting surface waves. Both models were set up to allow varying resolution and multiple nesting. In addition, POM was set up to be easily relocatable to allow rapid deployment of the model for any region of interest within the Mediterranean Sea. A common requirement for both models is the need for atmospheric forcing. Both models require time varying wind or wind stress. In addition, the hydrodynamic model requires initial conditions as well as time dependent surface heat fluxes, fresh water flux, and lateral boundary conditions at the open boundaries. Several sources of atmospheric forcing have been assessed based on their availability and their impact on the quality of the ocean models' forecasts. The various sources include operational forecast centers, other research centers, as well as running an in-house regional atmospheric model. For surface waves, higher spatial and temporal resolution of the winds plays a central role in improving the forecasts in terms of significant wave height and the timing of various high wave events. For the hydrodynamics, using the predicted wind stress and heat fluxes directly from an atmospheric model can potentially produce short range ocean forecasts that are nearly as good as hindcasts forced with gridded atmospheric analyses. Finally, a high-resolution, nested version of the model has shown to be stable under a variety of forcing conditions and time scales, thus indicating the robustness of the selected nesting strategy. For the southeastern corner of the Mediterranean, at forecast lead times of up to 4 days the high-resolution model shows improved skill over the coarser resolution driving model when compared to satellite derived sea surface temperatures. Most of the error appears to be due to the analysis error inherent in the initial conditions.     

Recovery of North-East Atlantic temperature fields from profiling floats: Determination of the optimal float number from sampling and instrumental error analysis

Argo is an international project that is deploying an array of temperature and salinity profiling floats over the global ocean. Here we use the error formulation derived from Optimal Statistical Interpolation to estimate statistical errors associated with the recovery of the temperature field in the North-East Atlantic ocean. Results indicate that with the present distribution of floats (119 in the considered domain), scales of wavelength larger than 500 km can be recovered with a relative uncertainty (rms error relative to the standard deviation of the field) of about 7% at 50 m, 8% at 200 m and 10% at 1000 m. This corresponds to mean absolute errors of 0.111 °C at 50 m, 0.104 °C at 200 m and 0.073 °C at 1000 m.The splitting of total errors into instrumental and sampling contributions reveals that, in the present scenario, errors are more due to the small number of floats than to instrumental errors, especially at upper levels. For scales larger than 500 km this will hold true until 200–250 floats are deployed (less than 200 for deep levels). In such a simulated scenario, the number of observations and the technology become approximately equally limiting factors for the accuracy of the temperature field mapping, with total relative errors of less than 2% at upper levels and about 3% at 1000 m.     

青藏铁路施工期环境保护管理实践

研究目的：对施工期的环保管理的组织体系、制度体系和环保工作措施进行阐述，以期为其它地区铁路或公路建设中的环保工作提供借鉴。研究方法：结合青藏铁路施工的实践经验，从组织、制度、措施等方面对施工期间的环境保护管理进行阐述。研究结果：铁路建设中，通过对施工期的环保管理实施了一系列的创新和实践，有效地控制了铁路施工对沿线生态环境的影响，并取得了显著的环保管理成效。     

跨海电气化铁路特大桥接触网防腐蚀设计研究

通过研究金属腐蚀机理和试验的方式,构建跨海电气化铁路接触网防腐蚀技术设计,保证接触网在海洋大气环境中使用寿命。通过防腐理论研究及盐雾试验验证,结论:(1)热浸镀锌防腐技术处理的钢材质构件在海洋大气环境适用过程中,防腐耐久性很难满足长期适用要求;(2)钢材质构件、铝合金材质构件采用涂层防腐处理,可以大幅度地提高金属表层的抗防腐能力,延长金属构件的使用寿命;(3)铝合金材质构件在典型的大气环境下抗腐蚀能力要强于钢材质构件。