陶瓷粉体特性及激光粒度分析中若干影响因素

介绍了几种常用陶瓷粉体的一般特性，及其在材料烧结中所起的作用。研究了用激光法测定这些粉体粒度及其分布时的若干因素，如样品分散体系浓度、分散介质种类、分散剂等对测试结果准确性的影响。结果表明要得到准确的测量结果，首先要制得分散度高、稳定性好的分散体系。     

Effect of surface modification of metal hydride electrode on performance of MH/Ni batteries

A novel method was applied to the surface modification of the metal hydride(MH)electrode of MH/Ni batteries.Both sides of the electrode were plated with a thin silver film about 0.1μm thick using vacuum evaporation plating technology,and the effect of the electrode on the performance of MH/Ni batteries was examined.It is found that the surface modification can enhance the electrode conductivity and decrease the battery ohimic resistance.After surface modification,the discharge capacity at 5C(7.5A)is increased by 212 mA.h and the discharge voltage is increased by 0.11 V,the resistance of the batteries is also decreased by 32%.The batteries with modified electrode exhibit satisfactory durability.The remaining capacity of the modified batteries is 89%of the initial capacity even after 500 cycles.The inner pressure of the batteries during overcharging is lowered and the charging efficiency of the batteries is improved.     

3PRS-XY混联型并联运动机床数控系统研究

设计了基于“Pc＋Turbo PMAC”开放模式的数控系统,实现3PRS-XY混联型并联运动机床的运动控制。利用Turbo PMAC开放的运动学计算功能,将运动学变换计算嵌入到Turbo PMAC中,在Turbo PMAC中完成轨迹粗插补,提高了控制系统的实时性和可靠性,降低了系统的开发周期。     

二次硬化合金钢中多组元强化相M2C碳化物的粗化动力学研究

高Co—Ni超高强度合金钢在482℃等温回火处理，首先析出渗碳体，回火30min后，针状合金碳化物M2C以共格方式从基体α—Fe中析出．回火时间延长到10h以上，M2C仍与基体间保持良好的共格关系，该共格关系会随过时效而失去．高分辨电镜观察表明，M2C的尺寸r和回火时间t接近r^2αt关系，明显偏离扩散控制的三次方关系的经典LSW粗化理论，对相近的合金钢材料有关M2C析出动力学实验数据进行分析得到相似的结论．这不仅和第二相碳化物的形态有关，还与多组元扩散的体系相关，表明经典理论不完全适合多组分的碳化物粗化行为从经典扩散理论出发，考虑针状沉淀相多元扩散问题，得到的针状相粒子粗化方程与实验结果吻合.     

Effects of oxygen and carbon on the magnetic properties and microstructure of Sm2Co17 permanent magnets

The research on the sintered Sm2Co17 permanent magnets prepared by metal injection molding is still at the exploratory stage. Carbon and oxygen are two key factors that influence the magnetic properties. In this article, the effects of oxygen and carbon on the properties and microstructure of the magnets have been studied. The results indicate that oxygen consumes the effective Sm content of the magnets and forms Sm2O3-the non-magnetism phase, which result in the deterioration of the magnetic properties. Besides, the magnetic properties decrease in evidence with increasing carbon content. The main factor that affects the magnetic properties is the deterioration of the microstructure of the magnets. The Sm（Co, Cu）5 phase decreases, whereas the cell size increases with the increase of the carbon content. When the carbon content is above 0.43 wt.%, the Sm（Co, Cu）5 phase is not enough to form a uniform cellular microstructure. Thus the magnetic properties disappear. ZrC is detected in the magnets by XRD when the carbon content is above 0.21 wt.%. ZrC also reduces the properties of the magnets.     

PSZ／Mo功能梯度材料的有限元设计

利用有限元分析的方法，依据拉应力和比应力最小原则对PSZ／Mo功能梯度材料进行了优化设计，确定了FGM的最佳形状分布因子、层数和每一层的厚度。并对最优成分分布FGM在稳态隔热状态下所产生的温度场和热应力进行了计算，得出进行PSZ／Mo功能梯度材料优化设计所需考虑的主要因素。     

超声振动对石蜡铸坯凝固的影响

为了探索不同条件下使用超声振动对改善钢坯凝固组织结构的作用,试验对不同浇注温度、时间下有无超声振动的水冷凝固石蜡铸坯进行了对比研究,得到较低温度(62℃以下)时超声冷却对改善铸坯内部结构有很好的效果,但减小了收得率;浇注温度为72℃时,超声作用更多体现在搅拌石蜡液芯上,提高了铸坯的收得率,作用时间长时(20min)可以改善铸坯内部结构。     

The implications of serial correlation and time-lag effects for the impact study of climate change on vegetation dynamics – a case study with Hulunber meadow steppe,Inner Mongolia

Ecological time series data are widely used in ecological research thanks to the development of remote-sensing technologies and fixed ecological research stations. However, the serial correlation issue with time series, which violates the fundamental assumption of independence for traditional statistical models or analysis, is rarely considered by ecologists in vegetation–climate relationship research. In addition, the issue of time lags between climate change and vegetation response is also often ignored. Inadequate consideration of these issues produces misleading results in some cases. In this article, we propose an approach based on the Autoregressive Integrated Moving Average (ARIMA) model and the nonparametric test to address serial correlation issue and distribution requirements for the valid statistical analysis of time series data. With Hulunber meadow steppe as a case, we applied this approach to analyse the role of climate factors in vegetation dynamics based on leaf area index (LAI) data and climatic data. The results showed that the LAI dynamics of Hulunber meadow steppe were mainly related to temperature with the time lag of zero, whereas the impact of precipitation on LAI dynamics was not statistically obvious. The comparison of regression models that deal with serial correlation and residual normality to different extents showed that ignoring the serial correlation issue with time series data likely produces misleading results, highlighting the importance of serial correlation removal. The combination of nonparametric correlation tests with ARIMA-based cross-correlation analysis also proved quite useful in reducing the chance of spurious correlation and time lags resulting from outlier values in ARIMA-based cross-correlation.