Design and Implementation of Secondary Wire Feeders Feeding System

随着工业自动化的不断发展，焊接设备被广泛应用到各个加工制造行业中。同时电焊机技术也飞快发展。但作为电焊机其中的一个核心部分----送丝装置的发展就显得比较缓慢。送丝装置是焊丝的给进系统，精准的送丝是保证焊接质量的关键。 目前焊接系统绝大多数采用一级送丝系统，这使得送丝的距离受到极大限制，降低了焊接的效率。极少数的焊接系统有二级送丝系统，并且需配套专门的焊机才可使用，可移植性不高，且售价极高，难以在国内推广，为此开发一款通用、智能、价廉的二级送丝系统是电焊机技术发展的必然趋势。 本课题将直流电机控制技术、单片机控制技术与电焊机技术相结合，利用单片机高效的计算处理能力、光电编码器的转速反馈和直...Nowadays, following the fast development of the industry robotization, the welding machine have been applied widely to all kinds of manufacturing field. Meanwhile, the technology for the welding machine is developing very fast. But the welding feeder technology developed looks a little slow which is the feeding system and the key unit of the welding machine. At present, most welding machine adopt...学位：工程硕士院系专业：信息科学与技术学院自动化系_控制工程学号：X200522303

Synthesis, Microstructure and Photoluminescence Properties of Continuous Freestanding Silicon Carbide Films by Melt Spinning of Precursor

SiC作为第三代宽带隙半导体材料因具有禁带宽度大、热导率高、耐高温、抗辐射、机械强度大和化学稳定性好等特性而成为制作高温、高频、大功率和极端条件下半导体器件的理想材料，已广泛应用于微机电系统(MEMS)、短波光电子器件及发光二极管等领域。由于制备SiC体单晶困难且昂贵，SiC薄膜的异质外延生长显得尤为重要，但目前外延生长SiC薄膜均借助基材进行沉积，存在晶格和热膨胀系数失配等问题，导致界面处存在因应力失配而引起的大量缺陷，使其发光效率降低，使用寿命缩短。因此，有必要寻求无界面缺陷的SiC薄膜制备工艺与方法。此外，SiC薄膜是较好的蓝光发射材料，但其属于间接跃迁半导体，发光效率较低是制约其在发光...Silicon carbide (SiC) films exhibit several advantages such as wide band gap, good radiation resistance, high thermal conductivity, superior mechanical strength and chemical inertness. These unique properties endow SiC films with great potential for applications in the power microelectromechanical systems (MEMS) in harsh environments, high-temperature electronic and optoelectronic devices applicat...学位：工学博士院系专业：材料学院材料科学与工程系_材料学学号：2052006015320

Research on NC Machining Technology Based on Cutting Tool with Forward and Backward Motion

通过分析常规数控加工中存在的问题,提出了一种刀具在进给方向上可进让式进给切削工件曲面轮廓的新工艺方法,建立了进让式进给切削数学模型,并从被加工工件的几何形状、切削过程中刀具受力情况及切削区的切削热释放情况等方面,具体分析了采用该方法对加工精度的改善情况,并给出了算法步骤。试验结果表明,新方法有利于减小工艺系统的变形,显著提高了工件的加工精度。Based on analyzing problems that general NC machining process existed,this paper proposed a machining method of cutting tool forward-and-backward machining work piece in feed direction.The calculation model of cutting location was established,and the advantages of this process included a superior surface finish,low tool pressure and cutting heat released easily in the cutting section.Finally,experiments and data were shown.The advantages were illustrated by reducing deformation of machining complex and achieving higher machining precision.校引进人才科研启动资金项目(ZRC2008221

Research on NC machining technology based on cutting tool creep-feed in feed direction

【中文文摘】通过对数控加工中存在的问题分析,提出了一种在数控加工中,刀具在被加工工件曲面上沿进给方向蠕动式切削加工的方法,通过刀具与工件时续分离和切削,改善了工艺系统的刚性,从而使工件的加工精度得到改善,并具体从被加工工件的几何形状、切削过程中刀具受力情况及切削区的切削热释放情况方面,分析了采用该方法对加工精度的改善情况。 【英文文摘】Based on analyzing problems that general NC machinining process exists, this paper proposes a machining method cutting tool creep-feed machining work piece in feed direction .When cutter is fed toward and away from work piece,it can improve the rigidity of mechanics system,so that machining precision is improved. Other advantages of this process include a superior surface finish,low tool pressure, and cutting heat released easily in the cutting section

人牙本质的动电效应研究

目的探讨人牙本质的流动电位现象,初步考察其影响因素。方法利用实验室自制的微型动态加载装置,结合应变仪和材料力学性能试验机,建立流动电位连续测量系统,测量人牙本质在模拟人体生理环境的介质中的流动电位,并研究不同的加载频率(0.2、0.1、0.05Hz)和牙试样上人为引入的小通孔对于流动电位的影响。结果人类牙本质呈现流动电位效应,载荷频率越高,测得的流动电位越大。这是因为频率越高,液体通过牙本质小管的流速越快,样品上下表面的压力差值越大,使流动电位增大。并且样品上人为钻一个小通孔(模拟龋齿)会使其流动电位峰值减小。结论人类牙本质具有动电效应,并且加载频率越高流动电位越高,在相同加载频率下引入小通孔样品的流动电位较低

空气环境下退火温度对连续SiC自由膜结构与发光特性的影响

采用熔融纺膜与先驱体转化法相结合制备出连续SiC自由薄膜,研究薄膜在1300,1400,1500℃温度下空气退火处理的氧化行为,以及退火温度对薄膜微观结构、光致发光特性(PL)、硬度和电阻率的影响。结果表明,SiC薄膜在1300℃具有较佳的抗氧化和发光特性,随着退火温度的升高,薄膜的抗氧化和发光特性略有降低,薄膜中无定型SiOxCy减少,-βSiC晶粒长大及游离碳增多,薄膜表面硬度与电阻率下降,表面惰性致密氧化层的生成保护阻挡氧扩散,从而有效减缓薄膜进一步被氧化

细菌还原Au--(3+)制备金催化剂的研究

从不同来源的细菌菌株筛选获得一株吸附还原Au3＋较强的菌株d01，经鉴定为巨大芽孢杆菌（bACIluSMEgATHErIuM）d01。菌株d01在Au3＋浓度600Mg/l下仍能较好生长。从电化学反应表明，该菌具有较强的还原力，它能将金催化剂的前驱体Au3＋/αfE2O3还原成具有催化CO＋O2→CO2的高分散度的Au0/αfE2O3催化剂国家自然科学基金;固体表面物理化学国家重点实验室资

先驱体法制备连续SiC自由薄膜及其发光性能

以聚碳硅烷(polycarbosilane,PCS)为先驱体,熔融纺出连续PCS自由原膜,并在190℃下对其进行1,2,3h和6h氧化交联,在900℃预烧及最终分别在1200℃和1300℃烧成,制得系列SiC自由薄膜。采用红外光谱、Raman光谱、X射线衍射、透射电镜与扫描电镜对薄膜进行微观结构与形貌分析。测量了薄膜的室温光致发光特性。结果表明:连续SiC自由膜均匀致密,含有β-SiC微晶、无定形SiOxCy及C簇;薄膜在410～450nm范围内有较强的蓝光发射,1200℃烧结的薄膜随交联时间增加,发光强度增大;而1300℃烧结的薄膜的发光强度相对下降,且交联时间越长强度下降越明显。412nm发光峰可归结于C簇发光;而435nm附近的峰则是薄膜中富含的Si—O,Si—C等键中的缺陷态构成的发光中心,在β-SiC晶粒中电子受到激发与缺陷态产生辐射复合引起发光以及量子表面效应共同作用的结果

Elemene reversed the multidurg resistance of A549 /DDP lung cancer cells via mitochondrial apoptosis pathway

目的:探讨榄香烯乳(ElEMEnE,ElE)逆转人肺腺癌耐顺铂(CISPlATIn,ddP)细胞A549/ddP的耐药性及作用机制。方法:采用MTT法检测榄香烯乳单用的细胞毒作用及与ddP合用时耐药逆转作用。荧光探针JC-1结合激光共聚焦显微镜检测线粒体膜电位的变化。dCfH-dA荧光探针结合流式细胞仪检测细胞内活性氧(rEACTIVE OXygEn SPECIES,rOS)水平。用谷胱甘肽试剂盒结合分光光度法检测计算gSH/(gSSg+gSH)比值。蛋白质印迹法检测胞质中CyTO C、PrO-CASPASE-3、CASPASE-3和bCl-2家族蛋白表达情况。结果:不同浓度榄香烯乳抑制A549/ddP细胞株生长,呈时间-剂量依赖性效应,联合顺铂能提高A549/ddP细胞株对顺铂的敏感性而逆转耐药。不同浓度榄香烯乳联合顺铂使A549/ddP细胞株线粒体膜电位下降,rOS浓度增加,gSH/(gSSg+gSH)比值降低,上调胞质中CyTO C、CASPASE-3、bAd蛋白表达,下调PrO-CASPASE-3、bCl-2蛋白表达。结论:榄香烯乳逆转A549/ddP细胞株耐药性可能与其损伤线粒体膜,活化胞内氧化还原体系,诱导线粒体凋亡路径有关。Objective: To explore the mechanism that elemene( ELE) reversed the multidurg resistance( MDR)of A549 /DDP lung adenocarcinoma cell.Methods: MTT assay was used to determine the growth inhibition of human lung adenocarcinoma A549 /DDP cells in vitro.Mitochondrial membrane potential( MMP) was monitored by JC- 1fluorescence probe with laser confocal scanning microscopy,the intercellular reactive oxygen species( ROS) level was measured by 2',7'- dichlorfluorescein- diacetate( DCFH- DA) staining and flow cytometry and the ratio of GSH /( GSSG +GSH) was calculated according to detection results of GSH kit.The expression of Cytochrome C,Caspase-3 and the Bcl- 2 family proteins and in the case of cyclosporine A and DEVD- CHO,the expression of Caspase- 3expression were measured by Western blot.Results: MTT results showed that different concentrations ELE could inhibit the proliferation of A549 /DDP cells in a time- and dose- dependent manner.Intriguingly,ELE plus cisplatin enhanced the sensitivity of A549 /DDP cells to cisplatin and reversed A549 /DDP cells dury resistance.Different concentrations ELE decreased mitochondrial membrane potential,increased intracellular ROS concentration and decreased GSH /( GSSG + GSH) ratio of A549 /DDP cells in a time- and dose- dependent manner.Furthermore,the combination with both ELE and cisplatin also enhanced the protein expression of Cytoplasmic C,Caspase- 3 and Bad,and reduced the protein levels of Bcl- 2 and Pro- caspase- 3 in the cisplatin- resistant A549 /DDP cancer cells.Conclusion: ELE reversed the MDR of A549 /DDP cell line may demage mitochondrial membrane,active intracellular redox system and induce the mitochondrial apopotosis pathway.福建省自然科学基金面上项目(编号:2010D014

The efect of elemene reversing the multidurg resistance of A549/DDP lung cancer cells

目的 :探讨榄香烯乳(ElEMEnE)逆转人肺腺癌耐顺铂(CISPlATIn,ddP)细胞A549/ddP的耐药性及可能的作用机制。方法 :采用MTT法检测榄香烯乳单药作用时的细胞毒作用及与ddP联合作用对A549/ddP细胞耐药的逆转作用;HOECHST 33342法进行细胞核染色,荧光显微镜下观察细胞形态的改变;fCM检测细胞凋亡率;蛋白质印迹法检测细胞质中细胞色素C(CyTOCHrOME C,CyT C)、PrO-CASPASE-3、CASPASE-3和抗凋亡因子b细胞淋巴瘤-2(b CEll lyMPHOMA-2,bCl-2)家族蛋白表达的情况。结果 :不同浓度榄香烯乳对A549/ddP细胞均有一定的抑制作用,呈时间-剂量依赖性效应,联合ddP能提高耐药细胞株A549/ddP对ddP的敏感性而逆转其耐药性。HOECHST 33342法和fCM法检测结果显示,榄香烯乳联合ddP能更大程度上诱导A549/ddP细胞的凋亡,提高耐药细胞的凋亡率,同时还上调A549/ddP细胞质中CyT C、CASPASE-3和bAd蛋白的表达,而下调PrO-CASPASE-3和bCl-2蛋白的表达。结论 :榄香烯乳能逆转A549/ddP细胞耐药性可能与其损伤线粒体膜,使线粒体释放CyT C到细胞质、同时活化CASPASE-3、上调促凋亡蛋白bAd和下调抗凋亡蛋白bCl-2表达以启动凋亡路径有关。Objective: To investigate the effect of elemene on the drug resistance of cisplatin(DDP)- resistant human lung adenocarcinoma A549/DDP cells, and its possible mechanism.Methods: The growth inhibition of A549/DDP cells treated with elemene alone or combined with different concentrations of DDP was detected by MTT assay.The morphological changes of apoptosis of A549/DDP cells treated with different concentrations of elemene(20 and 40 μg/mL) for 24 h were observed by Hoechst 33342 staing under fluorescence a microscope.The apoptosis rate of A549/DDP cells treated with different concentrations of elemene(20 and 40 μg/mL) after 24 h were detected by FCM(flow cytometry).The expressions of cytochrome C, pro-caspase-3, caspase-3 and the Bcl-2 family proteins were measured by Western blotting analysis.Results: MTT result showed that different concentrations elemene could inhibit the proliferation of A549/DDP cells in a time- and dose- dependent manner.Intriguingly, elemene plus DDP enhanced the sensitivity of A549/ DDP cells to DDP and reversed the resistance of A549/DDP cells.Elemene was also a strong inducer of apoptosis in this model system, and a synergistic effect on induction of cell death was observed when the tumor cells were treated with both agents.The result showed that elemene could enhance A549/DDP cell apoptosis.Furthermore, the combination of elemene and DDP also enhanced the protein expressions of cytochrome C, caspase-3 and Bad, and reduced the protein levels of Bcl-2 and pro-caspase-3 in the A549/DDP cells.Conclusion: The reversal of the multi-drug resistance of A549/DDP cell line by elemene may result from its effect on induction of apoptosis.Elemene treatment can impaire mitochondrial membrane, release cytochrome C into cytoplasm, activate caspase-3,up-regulate pro-apoptotic protein Bad and down-regulate anti-apoptotic protein Bcl-2, and finally caused apoptosis.福建省自然科学基金面上项目(编号:2010D014