道依茨1015柴油机增压器高原匹配研究

介绍了道依茨1015柴油机高原增压器故障情况,故障原因系压气机设计裕度不足,改进方案为：加大叶片厚度和减小叶轮的出口后弯角,试验室匹配试验表明,改进设计是成功的。     

Static and dynamic measurement‐based thermodynamic analysis of solid sorption refrigeration system

Pairs of low‐temperature (La_0.9Ce_0.1Ni₅ and La_0.8Ce_0.2Ni₅) and high‐temperature (LaNi_4.7Al_0.3 and LaNi_4.6Al_0.4) LaNi₅ hydrides were used for thermodynamic analysis of metal hydride‐based solid sorption refrigeration system (SSRS). In general, static pressure–concentration isotherm (PCI) properties were considered for the thermodynamic analysis of solid sorption thermodynamic cycles. But, the hydrogen transfer processes involved in the thermodynamic cycle are dynamic in nature. Therefore, in the present study, the dynamic PCIs of these metal hydrides were measured at different temperatures and compared with their static PCIs. Significant variation in PCI and thermodynamic properties were observed in dynamic conditions compared with static conditions. Later, the performance of SSRS was determined by using static and dynamic PCI properties. Refrigeration effect and coefficient of performance of SSRS decreased by 60% and 35% respectively, when dynamic (at 80 mi/min) PCI data were considered. Copyright © 2016 John Wiley & Sons, Ltd.     

藏北高原紫外辐射的变化特征

对藏北高原五道梁站及其邻的地区以及一些平均地区站点的太阳此外辐射观测资料进行了分析，并与青藏高原其它地区的观测结果进行对比，讨论了紫外辐射的变化特性及其影响因子。结果表明：１）紫外辐射的基本变化主要受天文因子的影响，其一般变化特征与总辐射有良好的对应关系。２）紫外辐射受大气臭氧含量的影响，其在太阳总辐射中占比例的变化是由大气臭氧含量南北不同的空间分布季节变化造成的。３）紫外辐射受测站海拔高度的影响     

高原环境下木材表面火蔓延特性的实验研究

在拉萨高原地区和合肥平原地区开展了一系列木材表面火蔓延对比实验研究,通过对火蔓延过程中一些重要特性参数(固相热解温度、气相火焰温度、燃烧区长度和燃烧速率等)的测量,分析了高原地区的火灾危害特性.结果表明,高原地区的固相热解温度与平原差别不大,但是气相火焰温度要略高一些.火蔓延过程中高原地区的燃烧区长度比平原的小,而且两...     

Effect of LaH3 additive on microstructures and hydrogen storage properties of V40Ti26Cr26Fe8 alloys prepared by hydride powder sintering method

Hydride-Powder-Sintering(HPS) as a new preparation approach was applied in the low cost V₄₀Ti₂₆Cr₂₆Fe₈ hydrogen storage alloys successfully, which provides an alternative preparation route for other types of hydrogen storage alloys. V₄₀Ti₂₆Cr₂₆Fe₈ alloy exhibits ideal hydrogen absorption-desorption performance after adding moderate content of LaH₃. Optimizing sintering process by increasing the sintering temperature and time has improved hydrogen desorption plateau evidently. X-ray diffraction analysis results show that the Ti-Oxide phase basically no longer exists when the LaH₃ content is greater than or equal to 3 wt% as compared to that of LaH₃ content below 3 wt%. Pressure-Compose-Temperature(PCT) curves show that the hydrogen absorption and desorption capacities increase gradually with the increase of LaH₃ content. The lattice parameters calculated by Rietveld refinement has the same variety rule as the hydrogen absorption-desorption capacities with the increase of LaH₃ content. It can be inferred that the addition of LaH₃ has reduced the content of Ti-Oxide and then the lattice parameters increase, which leads to the improvement of hydrogen performance of the alloy. The most appropriate preparation process is 3 wt% of LaH₃ additive with a sintering process 1673 K-6h, correspondingly, the hydrogen absorption and desorption capacities are 3.13 wt% and 1.97 wt%, respectively.     

典型海拔高度下弹道差异分析

针对高海拔气压影响武器射击能效发挥的问题,提出一套系统的枪弹高原射表编制方法。通过对高原和 平原试验数据分析处理,对比枪弹在高原和平原条件下外弹道特征量的变化,从理论上分析原因、总结规律,获得 一套系统的枪弹高原射表编制方法。计算验证结果证明,该方法可显著提高射表精度。     

Local Gamma-Ray Counting Efficiency of Halogen Counter with Thick Anode

A substance for solidifying waste containing ¹²⁹I is sought that effectively sorbs iodine to inhibit its release from repository into the environment. Three candidate media—commercial alumina cement mixed with calcium sulfate and/or calcium hydroxide—were investigated. The criterion applied for evaluating iodine sorption performance was the distribution coefficient Kd of iodine between solid and solution in an emulsion of sodium iodide solution and powder prepared from the alumina cement/calcium compound mixture, which was molded, cured and ground. Batch sorption experiments were performed on different combinations of the above-mentioned calcium compounds added to alumina cement. The solidified substance was also examined for mechanical strength. The highest iodine sorption performance was obtained with calcium sulfate added to alumina cement to a SC₄/Ca mole ratio of 0.16, which ensured a Kd value raised to a level of not lower than 0.2 m³/kg from the (1.8–3.2)x10^-3 m³/kg obtainable with alumina cement before calcium compound addition. The enhancement of iodine sorption with addition of calcium sulfate is attributed to formation in the substance of monosulfate (3CaO·Al₂O₃·CaSO₄12H₂O) or tetracalcium aluminate hydrate (4CaO·Al₂O3·XH₂O (X=13 to 19)).     

基于最大能量耗散率原理的黄土本构模型参数的研究

基于最大能量耗散率原理的黄土弹塑性本构模型，设计出获取该模型参数的室内试验方案，并以泾阳南塬为研究区域，研究不同含水率下Q₃马兰黄土本构参数的取值范围和硬化函数的形式。研究结果表明：泾阳南塬Q₃马兰黄土塑性剪应变的硬化函数呈双曲线型，其参数a取值范围在0.002至0.02之间，参数b在0.01至0.05之间；塑性体应变的硬化函数呈三次函数型，其参数m₁、m₂、m₃取值在0.001至1之间；体积模量K取值在40 MPa至130 MPa之间，剪切模量G取值在20 MPa至60 MPa之间；与试验数据对比验证，该本构模型通过试验方案取得的参数，可以准确地描述泾阳南塬Q₃马兰黄土的应力应变关系。     

柴油机高原适应性研究及压气机流场分析

基于试验测试数据建立增压柴油机的仿真模型,开展0～4000 m高原适应性研究工作,研究增压柴油机性能及压气机性能海拔变化关系,并研究不同海拔下压气机内部流动状况,分析压气机效率下降原因.研究结果表明:高海拔工况下,柴油机功率、转矩与燃油消耗率下降,进气流量减少,增压压力下降,压气机压比增大,效率下降.压气机子午面的相对...