Intensity Distribution Design for Laser-Induced Thermal Loading Based on Numerical Simulation

To accomplish laser-induced thermal loading simulation tests for pistons,the Gaussian beam was modulated into multi-circular beam with specific intensity distribution.A reverse method was proposed to design the intensity distribution for the laser-induced thermal loading based on finite element(FE) analysis.Firstly,the FE model is improved by alternating parameters of boundary conditions and thermal-physical properties of piston material in a reasonable range,therefore it can simulate the experimental resul..

宽带激光熔覆送粉喷嘴的结构设计与粉末流场研究

设计一种新型的送粉喷嘴结构,适用于宽带激光熔覆和增材制造。该结构使用多通道出口有效降低粉末流在扫描方向的发散角,通过添加内部整流圆柱调整粉末流在垂直扫描方向上的浓度分布。采用离散相模型,研究该喷嘴结构输出的粉末流场。优化分流圆柱的尺寸,使该送粉喷嘴能够输出浓度分布均匀的宽带粉末流,并沉积出厚度均匀的宽带涂层

独活寄生汤水提物对退变大鼠椎间盘软骨细胞功能的影响

目的探究独活寄生汤水提物对经IL-1β诱导退变的大鼠椎间盘软骨细胞中Wnt4、GSK-3β、β-catenin、DKK-1的影响。方法采用机械-酶消化法分离大鼠椎间盘软骨组织,进行软骨细胞体外培养、镜下观察与鉴定,分为正常组、模型组(经10 ng/m L浓度IL-1β造模)、实验1组(独活寄生汤水提物组200μg/m L干预24 h)、实验2组(独活寄生汤水提物组200μg/m L干预48 h)。观察4组大鼠椎间盘软骨细胞中Wnt4、GSK-3β、β-catenin、DKK-1 m RNA与蛋白的表达及上清液中Sox 9表达。结果 (1)第2代大鼠椎间盘软骨细胞增殖速度快,呈现多边形,胞核清晰,且含有1~2个核仁,融合后出现\"铺路石\"状,经Ⅱ型胶原法染色后,阳性对照组胞浆区域浸染为棕黄色;(2)与正常组比较,模型组中软骨细胞Wnt 4、GSK-3β、β-catenin m RNA与蛋白表达及上清液Sox 9含量明显提高(P<0.05),DKK-1 m RNA与蛋白表达明显降低(P<0.05);与模型组比较,实验1组、实验2组中软骨细胞Wnt 4、GSK-3β、β-catenin m RNA与蛋白表达及上清液Sox 9含量明显降低(P<0.05),DKK-1m RNA与蛋白表达明显提高(P<0.05),以实验2组变化最为显著(P<0.05)。结论独活寄生汤水提物组可调控退变椎间盘软骨细胞的功能,下调Wnt 4、GSK-3β、β-catenin和上调DKK-1 m RNA与蛋白表达,进而延缓大鼠椎间盘软骨细胞的退变。福建省自然科学基金项目(2017J01224);;福建中医药大学校管课题资助(X2015034

磺基水杨酸的分子内质子转移及其在酸性锡电镀液中的荧光快速测定

根据磺基水杨酸反常大的荧光Ｓｔｏｋｅｓ位移的实验现象，提出了它在一定条件下发生分子内质子转移的机理．据此建立了酸性锡电镀液中磺基水杨酸的直接快速荧光分析新方法．该方法不受共存组分干扰，５～１０ｍｉｎ可完成测定，测定的相对标准偏差小于３％

独活寄生汤调控对大鼠椎间盘软骨细胞Wnt/β-catenin信号通路的影响

目的:从Wnt/β-catenin信号通路探讨独活寄生汤水提物对大鼠椎间盘退变软骨细胞功能的影响。方法:（1）用水提加热回流法制备独活寄生汤水提物成分;（2）选取4周龄健康雄性SD大鼠30只,采用机械-酶消化法分离大鼠椎间盘软骨组织,建立软骨细胞体外培养体系并进行鉴定;（3）RT-PCR、We stern blot法分别检测经DKK-1抑制剂干预及（或）经白细胞介素-1β诱导的椎间盘软骨细胞Wnt4、GSK-3β、β-catenin mRNA与蛋白含量的表达。结果:（1）椎间盘软骨细胞经Ⅱ型胶原法染色后,阳性对照组胞浆区域浸染为棕黄色;（2）RT-PCR、Western blot检测结果示,与正常组比较,模型组Wnt4、GSK-3β、β-catenin mRNA与蛋白含量表达显著升高（P<0.01）;与模型组比较,独活寄生汤水提物组(100,200,400μg·mL-1)的Wnt4、GSK-3β、β-catenin mRNA与蛋白含量表达显著降低（P<0.01或P<0.05）,其中以200μg·mL-1组的表达量最低（P<0.01）。结论:独活寄生汤水提物组可通过调控Wnt/β-catenin信号通路,下调大鼠椎间盘退变关节软骨中Wnt4、GSK-3β、β-catenin mRNA与蛋白含量表达,从而延缓椎间盘软骨细胞退变。福建省自然科学基金(2017J01224);;福建中医药大学校管课题(X2015034

同步荧光法同时测定苯甲酸和水杨酸的研究

根据苯甲酸与水杨酸在酸性条件下荧光光谱出现的差异，用同步荧光法同时测定其混合物中二组份。苯甲酸及水杨酸的检测限分别为０．２４μｇ／ｍＬ和０．２５μｇ／ｍＬ，相对标准偏差分别为１．３％和１．２％。方法用于商品杀菌防腐剂中苯甲酸与水杨酸的同时测定，结果满意。Ａｂｓｔｒａｃｔ：Ｂａｓｅｄｏｎｔｈｅｅｖｉｄｅｎｔｄｉｆｆｅｒｅｎｃｅ，ｏｆｆｌｕｏｒｅｓｅｅｎｃｅｓｐｅｔｒａｃｈａｒａｃｔｅｒｉｓｔｉｃｓｂｅｔｗｅｅｎｂｅｎｚｏｉｃａｃｉｄａｎｄｓａｌｉｃｙｌｉｃａｃｉｄｉｎ１．０ｍｏｌ／ＬａｑｕｅｏｕｓＨ２ＳＯ４ｓｏｌｕｔｉｏｎ，ａｎｅｗｍｅｔｈｏｄｈａｓｂｅｅｎｅｓｔａｂｌｉｓｈｅｄｆｏｒｓｉｍｕｌｔａｎｅｏｕｓｄｅｔｅｒｍｉｎａｔｉｏｎｏｆｂｅｎｚｏｉｃａｃｉｄａｎｄｓａｌｉｃｙｌｉｃａｃｉｄｉｎｍｉｘｔｕｒｅｓｂｙｓｙｎｃｈｒｏｎｏｕｓｆｌｏｕｒｉｍｅｔｒｙ．Ｔｈｅｄｅｔｅｃｔｉｏｎｌｉｍｉｔｓｏｆｂｅｎｚｏｉｃａｃｉｄａｎｄｓａｌｉｃｙｌｉｃａｃｉｄａｒｅ：０．２４μｇ／ｍＬａｎｄ０．２５μｇ／ｍＬ，ｒｅｓｐｅｃｔｉｖｅｌｙ．Ｔｈｅｒｅｌａｔｉｖｅｓｔａｎｄａｒｄｄｅｖｉ

Numerical simulation of thermal behavior and multicomponent mass transfer in direct laser deposition of Co-base alloy on steel

During direct laser deposition process, rapid melting-solidification and addition of multicomponent powder lead to complex transport phenomena in the melt pool. The thermal behavior and mass transport significantly affect the solidified microstructure and properties of fabricated layer. In this paper, an improved 3D numerical model is proposed to simulate the heat transfer, fluid flow, solidification and multicomponent mass transport in direct laser deposition of Co-base alloy on steel. The solidification characteristics, including temperature gradient (G), solidification growth rate (R) and cooing rate (G x R), can be obtained by transient thermal distribution to predict the morphology and scale of the solidification microstructure. Multicomponent transport equation based on a mixture-averaged approach is combined with other conservation equations. The calculated melt pool geometry and the composition profiles of iron (Fe), carbon (C), cobalt (Co) and chromium (Cr) are compared with the experimental results. The results show that in the initial stage of direct laser deposition, the rapidly mixture of substrate material and added material occur in the melt pool and conduct plays an important role in heat transfer due to the low Peclet number. As the melt pool is developed, the heat and mass transfer in the melt pool are dominated by strong Marangoni convection. An unmixed zone is observed near the bottom of melt pool where the convection is frictionally dissipated due to the presence of solidified dendrites. Since the G/R decreases and G x R increases from the bottom to the top of the solidified track, the morphology of the microstructure changes from planar front to columnar dendrites to equiaxed dendrites and the grain size decreases. (C) 2016 Elsevier Ltd. All rights reserved

基于数值模拟的激光热负荷光强分布设计

To accomplish laser-induced thermal loading simulation tests for pistons,the Gaussian beam was modulated into multi-circular beam with specific intensity distribution.A reverse method was proposed to design the intensity distribution for the laser-induced thermal loading based on finite element(FE) analysis.Firstly,the FE model is improved by alternating parameters of boundary conditions and thermal-physical properties of piston material in a reasonable range,therefore it can simulate the experimental resul..