ASSESSMENT OF DAMAGE AND LIFE PREDICTION OF AUSTENITIC STAINLESS STEEL UNDERHIGH TEMPERATURE FATIGUE CREEP INTERACTION CONDITION

１．ＩｎｔｒｏｄｕｃｔｉｏｎＡｈｉｇｈｔｅｍｐｅｒａｔｕｒｅｌｏｗｃｙｃｌｅｆａｔｉｇｕｅｅｘｐｅｒｉｍｅｎｔｗｉｔｈａｔｅｎｓｉｌｅｈｏｌｄｔｉｍｅａｔｔｈｅｐｅａｋｔｅｎｓｉｌｅｓｔｒａｉｎ（ｃｒｅｅｐｆａｔｉｇｕｅｉｎｔｅｒａｃｔｉｏｎ）ｉｓｏｎｅｏｆｔｈｅｔｅｓｔｓｆｏｒｕｎｄｅｒｓｔａｎｄｉｎｇｌｉｆｅｌｉｍｉｔｉｎｇｐｈｅｎｏｍｅｎａｉｎｍａｎｙｃｏｍｐｏｎｅｎｔｓｕｓｅｄｉｎｐｏｗｅｒｇｅｎｅｒａｔｉｏｎａｎｄａｅｒｏｎａｕｔｉｃｓ．Ｍａｎｙｃｏｍｐｏｎｅｎｔｓｏｐｅｒａｔｉｎｇ…     

采用气雾化Zn-22%Al粉末挤压制造微型螺旋齿轮(英文)

基于Zn-22%Al共析合金的超塑性,采用粉末挤压工艺制造微型螺旋齿轮,以减小成形压力和获得细小的显微组织。该螺旋齿轮的规格为:模数0.3,齿数1.2,螺旋角15°。将粉末压制坯通过烧结和固溶热处理进行致密化。致密化的坯料由层状和细晶状组织组成。在温度250°C,应变速率2.36×10-3和1.18×10-1s-1的条件下对坯料进行挤压,并对挤压成形的螺旋齿轮的力学性能进行测试。     

功率分流混合电动车辆动力系工作优化(Ⅱ)

本文讨论如何处理好控制混合电动车辆的动力系,基于多目标优化推荐了一个功率分流混合电动车辆的优化工作。开发了一个准静态动力系模型,探索了整个工作选择的空间,以便找到一个可达到的最佳工作可选择的组合。采用这种概念,开发了二种模拟:模拟一是基于等量燃油消耗量最小,其二是采用动态优化。按结果的分析和比较,按最小的等量燃油消耗找出几乎最高的效率,作为按优化控制模拟求得理论上最大的性能。结果除了在高动力负荷工况外不表示显著的差异。根据这个分析,同时为车辆在纯电动车辆工作模式推荐了一个临界值。     

功率分流混合电动车辆动力系工作优化

本文讨论如何处理好控制混合电动车辆的动力系,基于多目标优化推荐了一个功率分流混合电动车辆的优化工作.开发了一个准静态动力系模型,探索了整个工作选择的空间,以便找到一个可达到的最佳工作可选择的组合.采用这种概念,开发了二种模拟:模拟一是基于等量燃油消耗量最小,其二是采用动态优化.按结果的分析和比较,按最小的等量燃油消耗找出几乎最高的效率,作为按优化控制模拟求得理论上最大的性能.结果除了在高动力负荷工况外不表示显著的差异.根据这个分析,同时为车辆在纯电动车辆工作模式推荐了一个临界值.     

Influence of Nitrogen Flow Ratio on the Microstructure, Composition, and Mechanical Properties of DC Magnetron Sputtered Zr-B-O-N Films

Nanocrystalline ZrB 2 film and nanocomposite Zr-B-O-N films were prepared by non-reactive as well as reactive magnetron sputtering techniques, respectively. By means of X-ray diffraction analysis, electron probe microanalysis, X-ray photoelectron spectroscopy, and scanning electron microscopy, the influence of nitrogen flow ratio on the film microstructure and characteristics were investigated systematically, including the deposition rate, chemical compositions, phase constituents, grain size, chemical bonding, as well as cross-sectional morphologies. Meanwhile, the hardness and adhesion of above films were also evaluated by micro-indentation method and a scratch tester. With increasing the nitrogen flow ratio, the deposition rate of above films decreased approximately linearly, whereas the contents of N and O in the films increased gradually and tended to saturation. Moreover, the film microstructure was also altered gradually from a fine columnar microstructure to a featureless glass-structure. As the nitrogen flow ratio was 11.7%, the Zr-B-O-N film possessed an typical nanocomposite structure and presented good mechanical properties. During the process of reactive sputtering of metal borides, the introduction of nitrogen can show a pronounced suppression of columnar grain growth and strong nanocomposite structure forming ability.     

LARGE EDDY SIMULATION （LES） OF TURBULENT FLOW BY FINITE DIFFERENCE METHOD

A Large Eddy Simulation (LES) technique was applied to solve the turbulent channel flow for Rer = 150.Three types of turbulence models are employed, such as the Smagorinsky model, the Dynamic Sub-Grid Scale(SGS) model and the Generalized Normal Stress (GNS) model. The simulated data in time series for the LES were averaged in both time and space to carry out the statistical analysis. Results of LES were compared with that of a DNS. As an application, a LES technique was used for 2D body in order to check the validation by investigating the turbulent vortical motion around the afterbody with a slant angle.     

Effects of elastic-plastic properties of materials on residual indentation impressions in nano-indentation using sharp indenter

One of the primary features of nano-indentation technique is that the contact area induced by an indenter is indirectly measured by a relationship between the penetration depth and the known geometry of the indenter.However,this indirect measurement occasionally leads to inaccurate properties of the indented material.The objective of this study is to investigate the effects of E/σr and the strain hardening exponents n of materials on the behaviors of pile-up and sink-in in nano-indentation and to predict n values of materials from the residual indentation impressions.The relations between the residual indentation profile and n value of the indented material were identified by dimensional analysis.Also,they were numerically formulated using FE analysis of nano-indentation for 140 different combinations of elastic-plastic parameters such as E,σy and n.The parameters of hrp/hm,herp/hm,Rr/hm and HOP/Hreal were introduced as various dimensionless parameters to represent and quantify the residual indentation profile after indentation.They were subsequently characterized as dimensionless functions using n and E/σr values.Finally,the validity of these functions was verified through 3D FE analysis of nano-indentation for Al 6061-T6 and AISI 1010 materials.     

把人参二醇类皂苷转化为Rg3的特种人参皂苷糖苷酶生成的细菌筛选

采用TLC、HPLC等酶活力检测方法对Arthrobacter sp．3、Rhodanobacter sp．14、Rhodopseudomonas sp．18和Enterobacter sp．20菌进行了菌种筛选。其中Arthrobacter sp．3、Rhodopseudomonas sp.18和Enterobncter sp．20菌发酵生成把人参二醇类皂苷PPD转化为Rg3、Rh2和苷元的特殊人参皂苷糖苷酶，Arthrobacter sp．3菌发酵产酶速度相对快一些。Rhodanobacter sp．14发酵主要生成能把人参二醇类皂苷PPD转化为Rd的人参皂苷糖苷酶。Rhodanobacter sp．14发酵生成的人参皂苷糖苷酶对丙酮抗性较好，Arthrobacter sp．3、Rhodopseudomonas sp．18和Enterobacter sp．20菌所生成的人参皂苷糖苷酶对丙酮抗性略差。综合各因素，选取Arthrobacter sp．3为目标菌种。     

Investigation of drying characteristics of low rank coal of bubbling fluidization through experiment using lab scale

Lignite is a low rank coal which is evenly distributed throughout the world and accounts for 45% of the total coal reserves. As it has a higher moisture content, its moisture content must be reduced in order to utilize it in power plant. In the present work, experiments on lignite has been done using a lab scale fluidized-bed reactor. Drying lignite through fluidized-bed reactor has a higher drying rate because there is good contact between particles and gas in the fluidized-bed reactor. Fluidized-bed dryin...     

Heating performance of a ground source heat pump system installed in a school building

The heating performance of a water-to-refrigerant type ground source heat pump system is represented in this paper under the actual working conditions of the GSHP(ground source heat pump) system during the winter season of 2008.Ten heat pump equipments with the capacity of 10 HP each and a closed vertical typed-ground heat exchanger with 24 boreholes of 175 m in depth were constructed.We investigated a variety of working conditions,including the outdoor temperature,the ground temperature,and the water tempe...