Calculation of thermodynamic parameters of U–Pu–N system with carbon and oxygen impurities

Mixed nitride fuels are being considered for advanced FBR, but very little is known about the thermodynamic properties of these fuels. For an overall composition of the nitride fuel with small amounts of oxygen and carbon impurities, thermodynamic properties, e.g. carbon activity and partial pressures of nitrogen, carbon-monoxide, plutonium and uranium, were calculated in present work. These calculations were based on standard Gibbs free energies of the binary compounds, present in this multi-component system (U,Pu)–C–N–O. For an over all composition of the fuel, stable phase-field was determined by minimization of the Gibbs free energy of the system. The fabrication experiences of various workers, reported in literature, have shown that depending on the impurity content, nitride fuel can exist in two phase fields, mono-nitride phase in equilibrium with sesquinitride phase or mono-nitride phase in equilibrium with dioxide phase. Therefore, in present calculations special attention was given to the thermodynamic behavior of these two phase-fields. A comparison of calculated thermodynamic properties indicated that nitride fuel with dioxide as second phase will be superior to the one with sesquinitride.     

07MnCrMoVR水电钢的生产工艺及组织性能

采用激光共聚焦扫描显微镜对07MnCrMoR水电钢奥氏体晶粒长大的动态过程进行了原位观察,并对其静态CCT曲线进行了测定,利用淬火机和热处理炉对38 mm厚的试验钢进行了淬火和回火试验。结果表明:试验钢在1200℃以下加热时奥氏体晶粒长大趋势不明显;当冷却速率为0.05~0.25℃/s时,试验钢的组织转变为多边形铁素体+珠光体,冷却速率为0.5~20℃/s时转变为贝氏体组织,冷却速率为20~50℃/s时转变为马氏体组织;930℃淬火后,试验钢的组织转变为板条贝氏体+马氏体,600℃回火后转变为铁素体+回火贝氏体,大量的碳化物在铁素体基体上析出,其屈服强度为602 MPa,抗拉强度为713 MPa,-20℃低温冲击吸收能量为259 J,力学性能高于国家标准的要求,为最佳的调质生产工艺。     

S-07钢在高压充气阀芯中的替代应用研究

目的解决高压充气阀S-03钢渗氮阀芯生产过程中周期长、合格率低、渗氮层开裂和贮存过程中锈蚀及方向漏率超标等问题。方法结合S-03钢渗氮阀芯工艺流程,分析其生产及贮存过程中存在的问题,并提出由S-07钢替代S-03钢渗氮工艺,从防锈、硬度和强度3个方面进行两种材料特性理论分析,同时进行耐蚀性试验、功能性试验、力学环境试验和寿命试验考核。结果 S-03钢渗氮阀芯经历湿热试验20 d后,出现轻微锈蚀,盐雾试验96 h后,锈蚀严重,而同条件下的S-07钢阀芯无锈蚀。S-07钢阀芯经过了功能性试验,x,y,z这3个方向的力学环境试验,动作200次的寿命考核试验后,动作灵活,功能测试合格。结论充气阀阀芯完成了S-07钢替代工艺研究,成功解决了影响充气阀功能的阀芯锈蚀问题和渗氮层开裂问题,同时使生产效率提高了约70%,生产成本降低了约50%。     

Rotational and helical surface approximation for reverse engineering

Given a surface in 3-space or scattered points from a surface, we investigate the problem of deciding whether the data may be fitted well by a cylindrical surface, a surface of revolution or a helical surface. Furthermore, we show how to compute an approximating surface and put special emphasis to basic shapes used in computer aided design. The algorithms apply methods of line geometry to the set of surface normals in combination with techniques of numerical approximation. The presented results possess applications in reverse engineering and computer aided manufacturing.     

用单片机和EDA协同设计温度采集系统

本文介绍了一种用单片机和EDA协同设计温度采集系统,该温度采集系统能够实现PN结、热电阻(PT100)、热电偶(镍锘-镍硅K型)3种方式的温度测量。可以满足不同的测量范围、不同的测量精度及不同场合的需要。本设计采用EDA作为开发工具,搭配单片机控制,使得整个设计具有较新的设计思想。采用12ADC模数转换器,使得测量精度得到了极大地提高。数据处理采用现场可编程门阵列FPGA(EP1K30QC208-3),它极高的程序执行速度使得系统响应更快更精确。     

Development of TP310HCbN(07Cr25Ni21CbN) austenitic stainless steel tubes

Improving the unit heat efficiency,reducing coal consumption and the emission of CO₂ and meeting the requirements of environmental protection and energy conservation is the goal of the boiler and the power industry.Developments of large capacity and high parameter ultra-supercritical（USC） units are the tendency of the power industry.There is no doubt that the development of USC units is based on the development of materials, especially the materials used for super-heater and reheater in high-temperature USC boiler.Due to the long time exposure to the harsh environment,such as bearing the 600℃steam oxidation,and withstanding the corrosive flue gas and fly ash erosion,the materials require not only good high-temperature strength,but also a good corrosion resistance.In consideration of the requirements cited above,foreign countries had developed TP310HCbN （07Cr25Ni21CbN） austenitic heat-resistant steel.However,the domestic demands for this material still depend on import and the cost is high,so the boiler and the power industry expects eagerly that these steels can be produced by domestic metallurgical industry,especially Baosteel,to replace the imported products.In order to satisfy the requirements of domestic manufacturing super-heater and reheater used in ultra-supercritical power boiler,after developed T23、T91、T92、S30432 high pressure boiler tube,Baosteel began to develop TP310HCbN （07Cr25Ni21CbN）austenitic stainless steel tube in January of 2007.This study describes the composition design, the manufacturing process of product,and the assessment of performance of Baosteel’s TP310HCbN （07Cr25Ni21CbN）.The data indicates that properties of Baosteel’s TP310HCbN（07Cr25Ni21CbN） conform to the ASME SA-213 standard and GB5310 standard,so it can substitute the imported products and is suitable for manufacturing power station boiler of great capacity and high steam parameters.     

Field trial results of straw yield with different harvesting methods,and modelled effects on soil organic carbon. A case study from Southern Finland

We estimated the effects of different cutting heights and harvesting strategies on the amounts of harvestable residue biomasses and allocation of residue biomasses in the soil. A case study on regional straw biomass resources was performed with the different crops cultivated in Varsinais-Suomi (Southern Finland) at present (averages of 2003–2012) and in the predicted future warmer climate (scenario RCP 4.5, year 2055). We also estimated, with the help of the Yasso07 model, the effects of different residue incorporation intensities on soil organic carbon (SOC) at present and in the future warmer climate. The results suggested that cutting height has a significant impact on the amount of straw biomass incorporated in the soil and subsequent change in SOC. The impact depended on crop species and variety. When straw is collected and used e.g. in energy production, harvesting practices leaving greater stubble heights could help to maintain soil fertility. The Yasso07 model suggests that in the predicted future warmer conditions, more straw could be collected without decreasing SOC, as mineralization of SOC in the warmer climate is expected to increase less than organic carbon amendments caused by higher crop and root biomasses. Collection and usage of straw as a renewable energy source always decreases greenhouse gas (GHG) emissions in comparison to fossil fuels. However, collecting straw every second year instead of every year, even with higher stubble, would decrease field traffic and spare the soil from compaction and the farmer from extra work, while still significantly decreasing GHG emissions.     

Approximation of solution curves of underdetermined systems of nonlinear equations

Computation of solution curves of underdetermined systems of nonlinear equations is mostly performed using discrete predictor-corrector methods. Those methods calculate a discrete chain of points lying on the curve. In standard methods there is no way to guarantee that ana posteriori interpolation or other approximation of this set of points results in a curve, which lies in anɛ-neighborhood with ana priori prescribed toleranceɛ and it is difficult and expendable to construct atrial and error-extension of the discrete methods based on such a posteriori information. We choose another approach to solve this enhanced task. Our methods are based on a functional predictor-corrector principle, i.e. we construct operators, which correct iteratively given predictor functions into the wanted neighborhood. The numerical realizations of these techniques depend strongly on the different choices of the operator. One possibility, the so-called Spline collocation continuation is explained in detail to illustrate the principle of the methods.     

A discrete-time stable controller for an omni-directional mobile robot based on an approximated model

An adaptive controller based on multi-input fuzzy rules emulated networks (MIFRENs) is introduced for omni-directional mobile robot systems in the discrete-time domain without any kinematic or dynamic models. An approximated model for unknown systems is developed by using two MIFRENs with an online learning algorithm in addition to the stability analysis. The main theorem in this model is proposed to guarantee closed-loop performance and system robustness for all adjustable parameters inside MIFRENs. The system is validated by an experimental setup with a FESTO omni-directional mobile robot called Robotino^®. The proposed algorithm is shown to have superior performance compared to that of an algorithm that uses only an embedded controller. The advantage of the MIFREN initial setting is verified comparing its results with those of a controller that is based on neural networks.