Laser‐induced reversion of precipitates in an Al‐Li alloy: Study on temperature rise in pulsed laser atom probe

The influence of tuning the laser pulse energy during the analyses on the resulting microstructure in a specimen utilizing an ultra‐fast laser assisted atom probe was demonstrated by a case study of a binary Al‐Li alloy. The decomposition parameters, such as the size, number density, volume fraction, and composition of precipitates, were carefully monitored after each analysis. A simple model was employed to estimate the corresponding specimen temperature for each value of the laser energy. The results indicated that the corresponding temperatures for the laser pulse energy in the range of 10 to 80 pJ are located inside the miscibility gap of the binary Al‐Li phase diagram and fall into the metastable equilibrium field. In addition, the corresponding temperature for a laser pulse energy of 100 pJ was in fairly good agreement with reported range of solvus temperature, suggesting a result of reversion upon heating due to laser pulsing. Microsc. Res. Tech. 79:727–737, 2016. © 2016 Wiley Periodicals, Inc.     

S120伺服驱动器的使用

介绍S120做基本定位控制时,采用不同的回零方式对状态字的影响,修改电机与编码器正方向及故障复位后硬件开关对S120伺服的影响。     

The effect of tempering temperature on the microstructure and mechanical properties of ultrahigh strength 23CoNi steel plate

The effect of tempering temperature on microstructure and mechanical properties of 23CoNi steel plate has been studied. Tempering in the temperature range of 100-460℃, the ultimate tensile strength σb tends to change along a curve which has the shape of the letter “n“, the peak of the σb occurs in the range of 460-475℃, beyond the peak, σb deceasing as the temperature increasing. Tempering in the temperature range of 100-200℃, the impact property αku increases as the temperature goes up. After 200℃, αku goes down as the temperature increases, when the tempering temperature goes higher than 460℃, αku goes up again tempering at higher than 485℃, the acicular alloying carbides M2C precipitate from matrix. The orientation relationship between M2 C and matrix coincides with follows: (011)α//(001)M2c, [100]α//[100] M2c.We found out a new order phase B2 which dispersing in the matrix and the size is very small. This paper discusses the reason of the formation of this new order phase and the sequence of effects to mechanical properties. With the increasing of the tempering temperature, both MaC and new order phase growing up. As the tempering temperature goes beyond 470℃, the amount of retained austenite tends to go up, higher than 510℃, the growing up of reverted austenite is accelerative. It is identified that retained austenite is coming from the reverse transformation. Tempered at higher than 550℃, we can easily find the reversion austenite which contains much more Nickel than matrix does and emerged in the bulk form under TEM.     

传递函数的测试及实时控制和反演

提出了一种由软件构成的快速精确测试传递函数幅频相频曲线,并通过YSL专有技术在数据采集中实时实现传函控制和反演技术的新方法,而且在DASP软件中取得成功应用.文中给出了传函的理论基础和公式,传函测试和反演技术的原理框图、试验测试数据及结果的分析,此方法能使测试系统的频响在数采中实时优化(平坦化),频率范围更宽,测量精度...     

Palm Oil Fatty Acid Additive (POFA) Filled Natural Rubber Compounds ‐ The Effects of Temperature on Curing Characteristics,Dynamic Properties and Reversion

Abstract

The effects of temperature on curing characteristics, dynamic properties and reversion behaviour of palm oil fatty acid additive (POFA 2) filled natural rubber compounds were studied. The scorch time, t₂ and cure time, t₉₀ were found decrease with increasing POFA 2 concentration. At similar POFA 2 concentration the t₂ and t₉₀ also decreased with increasing cure temperature. For dynamic properties compared to control compound, the compounds with POFA 2 show higher maximum elastic torque but lower minimum elastic torque. At similar POFA 2 concentration, the maximum and minimum elastic torque decrease with increasing cure temperature. Results also indicate that the incorporation of POFA 2 and increment in cure temperature decrease the loss tan delta. Reversion decreased with increasing POFA 2 concentration whereas increasing the cure temperatures exhibits opposite trend.     

工程机械子午线轮胎胎肩垫胶的配方优化

对工程机械子午线轮胎胎肩垫胶的配方进行优化。结果表明：通过调整胎肩垫胶配方中的补强体系和硫化体系,并增加抗硫化返原剂PK900和HTS,胶料的门尼焦烧时间延长,抗硫化返原性明显改善;硫化胶的综合物理性能和动态力学性能较好;成品轮胎的耐久性能提高。     

精炼加工对玉米油营养指标和风险指标的影响

以玉米油为研究对象,测定了传统精炼过程中原油、中和油、脱色油及成品油的营养指标(植物甾醇、生育酚、角鲨烯)及风险指标(回色变化、玉米赤霉烯酮、3-MCPDEs和缩水甘油酯)的变化情况。结果表明,玉米油回色受原油中磷脂和生育酚含量影响较大,中和、脱色、脱臭工段可有效控制玉米赤霉烯酮,脱臭工段对玉米油营养指标、3-MCPDEs含量和缩水甘油酯含量均有较大影响。结合实验结果将实际精炼工艺参数调整为:中和温度70～85℃,中和时间不短于45 min;水洗过程使用检控氯离子的软水,用量大于8%。脱色工段采用柠檬酸(用量100 mg/kg)预脱色,将活性白土、凹凸棒土、膨润土等不同种类的白土根据原油指标进行混合添加,白土活性度选择120～150,脱色真空残压2. 5～3. 5 kPa,温度100～120℃,脱色时间20～30 min;脱臭工段脱臭温度235～245℃,脱臭时间60～80 min,绝对真空度不大于400 Pa,一般保持在200～300 Pa。生产实践表明,新工艺脱色剂用量降低20%,成品油色泽R1. 2,回色效应有所改善,ΔR由原工艺的1. 2下降至0. 8,生育酚、植物甾醇保留率均...     

地球同步轨道SAR曲线轨迹模型下的改进CS成像算法

地球同步轨道合成孔径雷达(GEO SAR)轨道高度高,合成孔径时间长,直线轨迹模型不再适用,导致常规的基于直线轨迹模型的成像算法性能下降。该文根据GEO SAR平台的运动特性,使用高阶逼近建立了曲线轨迹模型下的斜距方程,并结合级数反演法,推导了GEO SAR回波信号2维频谱高阶近似表达式。然后在此基础上提出了一种适用于GEO SAR曲线轨迹模型的改进Chirp Scaling(CS)成像算法。仿真结果表明该算法的斜距方程精度较高,能够精确校正距离徙动,实现全孔径高分辨成像。     

一种弹载侧视SAR大场景成像算法

导弹的俯冲加速运动所带来的较大距离徙动使得SAR成像难度较大。该文根据弹载SAR平台的运动特点,使用高阶逼近模型建立了SAR的回波信号模型。考虑到大场景下的距离空变问题,对目标斜距随时间的变化进行了详细的分析。结合级数反演法,得到了弹载SAR回波信号的2维频域的精确表达式。基于此式,提出了一种适用于弹载SAR俯冲加速运动下的大场景成像算法。理论分析和实验结果表明,该算法对较大场景取得了较好的成像效果,距离向和方位向分辨率都达到了理论分辨率。     

加工助剂Z210的基本特性及其在胎面胶中的应用研究

介绍了不饱和脂肪酸锌盐类加工助剂Z210的基本特性及其在轮胎胎面胶中的应用试验。结果表明，加工助剂Z210具有可缩短胶科塑炼时间、降低胶科门尼粘度、明显改善胶料的加工特性和抗硫化返原性、对硫化胶物理性能影响不大的特点，是值得推广应用的综合效果较好的加工助剂。