Characterization of the stress distribution and evolution inside a thermal barrier coating after initial thermal cycles

The residual stress introduced inside a thermal barrier coating (TBC) during manufacturing and service processes is one of the main causes of thermal barrier failure. The formation and evolution of internal stress in the TBC begin at the early stage of service, but studies on the mechanism of the distribution and evolution of the stress in the TBC during the initial thermal cycle are still lacking. To explore the evolution mechanism of the stress in the TBC interior, an experimental study on the regulation mechanism of the initial thermal cycle on the TBC internal stress was carried out in this paper. First, the internal stress of TBC specimens after thermal cycles was characterized based on photoluminescence spectroscopy (PL) and terahertz time-domain spectroscopy (THz-TDS) technologies, in which the homogenization of the near-interface stress field was observed during the initial thermal cycle. Then, the evolution of the microstructure and phase structure of the TBC specimens was characterized. Finally, the phenomenological model of the evolution of the TBC internal structure was established, revealing that the initial thermal cycle regulated the microstructure of the top coating (TC) through phase transformation to realize the homogenization of the near-interface stress field.     

大肠杆菌高效表达屎肠球菌纤维素结合域谷氨酸脱羧酶的条件优化

为了规避人肠杆菌(Escherichia coli)自身基因组表达的天然GAD的干扰,以再生无定形纤维素(regenerated amorphous cellulose,RAC)特异性吸附纤维素结合结构域谷氨酸脱羧酶(cellulose-binding domairr glutamate decarboxylase,CBD-GAD)制备的RAC-CBDGAD固定化酶作为评价指标,采用单因素和田口试验设计法对E.coli GDMCC60445高效表达CBD-GAD的条件进行了优化。结果表明,E.coli GDMCC60445表达CBD-GAD的适宜培养基为改良LB(Luria-Bertani)培养基,其组成为胰蛋白胨8 g/lL、酵母膏6 g/L、NaCl10g/L、pH 5.5;适宜的培养条件为温度37℃、摇床转速120 r/min、培养时间24 h。在该适宜条件下,RAC-CBDGAD活力为(419.79±10.37)U/g,与田口法预测值一致,较优化前提高了(30.28±3.22)%。     

基于频域介电谱法的变压器油纸绝缘套管受潮状况分析

近年来频域介电谱法(frequency domain spectrum,FDS)作为一种无损检测方法,逐渐被尝试用来检测大型变压器、套管等油纸绝缘设备的绝缘状态。采用该方法对某500 kV变电站主变压器高中压中性点套管及低压故障套管进行了现场离线测量,然后将所测结果与实验室结果进行比对,分析其故障原因,实现了对现场实测数据的定性和定量分析,确认该批次套管存在出厂时套管芯子干燥不充分问题。研究表明,频域介电谱法不仅能够定性地反映套管内部受潮状况和受潮原因,而且还可以对其受潮程度进行定量分析,从而为该方法在实际生产中的进一步应用提供了理论和实践基础。     

基于二值图像连通域提取的图像滤波方法

为解决常用滤波方法对目标图像噪声抑制效果不理想的问题,提出了一种基于二值图像连通域提取的图像滤波方法。将采集到的图像进行二值化,对图像进行连通域提取并根据连通域的轮廓筛选出噪声干扰点,对噪声点进行过滤,保留图像细节特征,对目标图像的噪声达到有效抑制的效果。结果表明:该方法在特定应用上优于常规滤波方法。     

均质机在乳品工业中的地位和应用

概述了均质机的发展，重点分析了柱塞泵高压均质机的功能、原理和基本结构以及在乳制品工业中的地位和应用、均质机选型和配套要点，同时概述了申鹿牌高压均质机的结构和材质的特点。     

时空尺度精细化对可中断负荷优化调度方案的影响研究

需求响应是中国现阶段缓解电力供应紧张局面的有效手段。在分析现有的大工业负荷参与的可中断负荷调度优化模型的基础上,通过算例揭示了现有调度方案可能存在的容量富余问题,研究了可中断负荷容量精细化和中断持续时间精细化对可中断负荷调度方案的影响,讨论了时空尺度精细化实施的可行性,提出一种精细的大工业负荷参与可中断负荷调度的优化模型。算例结果表明,精细化模型能充分利用大用户负荷在时空尺度上的特性,在保证用电高峰期削减负荷需求得到满足的同时,解决了现有调度方案可能存在的容量富余问题,优化了调度结果,降低了中断补偿成本,提高了用户满意度。     

Hybrid Chemical Reaction Optimization Approach for Combined Economic Emission Short-term Hydrothermal Scheduling

—This article presents the hybridization of a newly developed, novel, and efficient chemical reaction optimization technique and differential evolution for solving a short-term hydrothermal scheduling problem. The main objective of the short-term scheduling is to schedule the hydro and thermal plants generation in such a way that minimizes the generation cost. However, due to strict government regulations on environmental protection, operation at minimum cost is no longer the only criterion for dispatching electrical power. The idea behind the environmentally constrained hydrothermal scheduling formulation is to estimate the optimal generation schedule of hydro and thermal generating units in such a manner that fuel cost and harmful emission levels are both simultaneously minimized for a given load demand. In this context, this article proposes a hybrid chemical reaction optimization and differential evolution approach for solving the multi-objective short-term combined economic emission scheduling problem. The effectiveness of the proposed hybrid chemical reaction optimization and differential evolution method is validated by carrying out extensive tests on two hydrothermal scheduling problems with incremental fuel-cost functions taking into account the valve-point loading effects. The result shows that the proposed algorithm improves the solution accuracy and reliability compared to other techniques.     

基于激光传感器的船舶避碰预警系统的研究

利用激光传感器获取相对距离,方位角度、相对速度等参数,合理的选择设备和设计安装位置,通过组装调试、可靠性及抗干扰性分析等不同步骤,设计船舶防撞自动分析控制程序。能够自主的感知周围可疑障碍船只或不明物体。自主的分析判断预警并发出预警信号。本系统依托较高的性价比,将会有利于提高防撞系统在中小型船只普及,对船舶航行安全来讲是很有必要的。     

提高多联机用旋风式油分离器切线速度方法的数值模拟

对小型多联机用旋风式油分离器建立了三维稳态数值模型.气相场选用重整化群湍流模型（RNG k-ε）,油滴轨迹采用随机轨道（DRW）模型,研究了进气管管径、筒体直径和进气碰撞结构对油分离器切线速度分布和压降的影响.发现较小的进气管管径有利于提高油分离器的切线速度;筒体直径对切线速度的影响不大,但较大的筒体直径使压降增加明显;进气碰撞结构O获得了高分离效率和低压降的结合.     

基于可视锥理论的五轴加工刀具碰撞检验方法

针对复杂曲面数控加工中刀具与工件的碰撞问题,提出一种基于可视锥理论的刀具碰撞检验方法。根据点的可视性特点推导点的可视锥算法,对任意采样点进行可视锥模型构建,通过刀轴矢量与可视锥的布尔运算判断刀具与工件的碰撞,由此计算刀轴避免碰撞时应转过的最小夹角,并对旋转后的新刀轴矢量是否在机床刀轴可加工范围内进行检验。通过将该方法应用于整体叶轮加工中,可快速检验出发生碰撞的区域并对刀轴矢量进行修正,有效地解决了刀具在数控加工中的碰撞检测问题,为刀具路径规划提供了有效的检验方法。