Analysis and Comparison of Friction Stir Welding and Laser Assisted Friction Stir Welding of Aluminum Alloy

Friction Stir Welding (FSW) is a solid-state joining process; i.e., no melting occurs. The welding process is promoted by the rotation and translation of an axis-symmetric non-consumable tool along the weld centerline. Thus, the FSW process is performed at much lower temperatures than conventional fusion welding, nevertheless it has some disadvantages. Laser Assisted Friction Stir Welding (LAFSW) is a combination in which the FSW is the dominant welding process and the laser pre-heats the weld. In this work FSW and LAFSW tests were conducted on 6 mm thick 5754H111 aluminum alloy plates in butt joint configuration. LAFSW is studied firstly to demonstrate the weldability of aluminum alloy using that technique. Secondly, process parameters, such as laser power and temperature gradient are investigated in order to evaluate changes in microstructure, micro-hardness, residual stress, and tensile properties. Once the possibility to achieve sound weld using LAFSW is demonstrated, it will be possible to explore the benefits for tool wear, higher welding speeds, and lower clamping force.     

多种统计方法比较黄连姜制工序中影响生物碱含量的因素

目的：测定黄连不同姜制品中6种生物碱的含量,采用多种统计方法对数据进行分析,找出姜制工序中影响姜黄连质量的因素。方法：采用高效液相色谱法测定黄连不同姜制品中药根碱、非洲防己碱、表小檗碱、黄连碱、巴马汀及小檗碱的含量。运用主成分分析、聚类分析、LSD（Least-Significant Difference）检验、独立t检验对结果进行分析。结果：黄连经姜炙后,表小檗碱、黄连碱含量略有上升,药根碱、非洲防己碱、巴马汀、小檗碱含量略有下降,传统姜炙品中各成分含量均高于烘制品。聚类分析发现榨汁组和煮汁组可以聚为一类;烘法和炙法具有明显不同的聚类,对黄连姜制品中的6种生物碱之和进行LSD检验,亦表明烘法与炙法具有显著性差异。对榨汁组进行独立t 检验,结果表明姜汁与黄连饮片拌匀或闷润至透心在6种生物碱上无显著性差异,LSD与独立t 检验的结果与聚类分析的结果一致。结论：采用同一批次黄连炮制所得的姜制品中,姜的来源、不同方法制备的姜汁及闷润过程对6种生物碱影响不大,加热方式可能是影响姜黄连质量的因素。考虑到润至透心需加入大量水稀释姜汁,炒干所需工时较长,故辅料姜汁与黄连饮片拌匀吸尽即可。     

Effects of FSW Tool Plunge Depth on Properties of an Al-Mg-Si Alloy T-Joint: Thermomechanical Modeling and Experimental Evaluation

One of the main challenging issues in friction stir welding (FSW) of stiffened structures is maximizing skin and flange mixing. Among the various parameters in FSW that can affect the quality of mixing between skin and flange is tool plunge depth (TPD). In this research, the effects of TPD during FSW of an Al-Mg-Si alloy T-joint are investigated. The computational fluid dynamics (CFD) method can help understand TPD effects on FSW of the T-joint structure. For this reason, the CFD method is employed in the simulation of heat generation, heat distribution, material flow, and defect formation during welding processes at various TPD. CFD is a powerful method that can simulate phenomena during the mixing of flange and skin that are hard to assess experimentally. For the evaluation of FSW joints, macrostructure visualization is carried out. Simulation results showed that at higher TPD, more frictional heat is generated and causes the formation of a bigger stir zone. The temperature distribution is antisymmetric to the welding line, and the concentration of heat on the advancing side (AS) is more than the retreating side (RS). Simulation results from viscosity changes and material velocity study on the stir zone indicated that the possibility of the formation of a tunnel defect on the skin–flange interface at the RS is very high. Material flow and defect formation are very sensitive to TPD. Low TPD creates internal defects with incomplete mixing of skin and flange, and high TPD forms surface flash. Higher TPD increases frictional heat and axial force that diminish the mixing of skin and flange in this joint. The optimum TPD was selected due to the best materials flow and final mechanical properties of joints.     

民族药小茴香炮制前后化学成分的变化分析

目的:研究小茴香经不同方法炮制后化学成分的动态变化.方法:应用不同炮制原理对净制后的小茴香分别进行蜜制、黑牵牛制、"四"制和麸制,使用标准挥发油提取器提取炮制品中挥发油成分,检测其含量和物理常数,并利用毛细管气相色谱-电子轰击质谱联用仪对其进行分析.结果:小茴香经不同辅料炮制后挥发油含量显著降低;炮制前后反式-茴香脑含量均最高,生品中24种化合物经不同方法炮制后含量均发生了变化,且发生了转化,共新产生了18种化合物,其中乙酸里那酯、法尼烯、对-烯苯基芳香醚、薄荷酮和辛酸己酯为首次在小茴香药材中检测到.结论:扩展了气相色谱-质谱联用技术的应用范围,适用于对药材炮制变化的快速分析.     

七氟烷麻醉骨折老年患者苏醒期躁动应用右美托咪定的临床效果研究

目的研究骨折老年患者进行七氟烷麻醉后出现苏醒期躁动,使用右美托咪定的临床效果。方法将我院2012年12月～2013年12月收治的60例七氟烷麻醉苏醒后躁动的老年骨折患者作为研究对象,随机分为A,B两组,每组各30例;A组采取常规护理治疗,B组采用右美托咪定治疗。比较两组患者的躁动及生命体征变化情况。结果两组患者治疗前,疼痛及躁动情况近似;治疗后,两组患者疼痛、躁动情况均有所改善,B组改善情况明显优于A组（t=6．9939,3．1850;p=0．000）;两组患者治疗前,心率、呼吸频率及平均动脉压均显著上升;治疗后,B组上述指标的改善程度明显,与A组比差异显著（t=7．1292,11．5013,11．8361;p=0．000）;A组治疗后躁动率35．67％,导管脱出率30．00％,均明显高于B组的6．67％,0．00％;两组间差异显著（P〈0．01）。结论使用右美托咪定对于骨折老年患者进行七氟烷麻醉后出现的苏醒期躁动具有较好的疗效,患者治疗后,生命体征较为稳定,疼痛及躁动评分较治疗前显著降低,具有一定的临床价值。     

Tensile Properties and Fracture Behavior of Aluminum Alloy Foam Fabricated from Die Castings without Using Blowing Agent by Friction Stir Processing Route

Al foam has been used in a wide range of applications owing to its light weight, high energy absorption and high sound insulation. One of the promising processes for fabricating Al foam involves the use of a foamable precursor. In this study, ADC12 Al foams with porosities of 67%–78% were fabricated from Al alloy die castings without using a blowing agent by the friction stir processing route. The pore structure and tensile properties of the ADC12 foams were investigated and compared with those of commercially available ALPORAS. From X-ray computed tomography (X-ray CT) observations of the pore structure of ADC12 foams, it was found that they have smaller pores with a narrower distribution than those in ALPORAS. Tensile tests on the ADC12 foams indicated that as their porosity increased, the tensile strength and tensile strain decreased, with strong relation between the porosity, tensile strength, and tensile strain. ADC12 foams exhibited brittle fracture, whereas ALPORAS exhibited ductile fracture, which is due to the nature of the Al alloy used as the base material of the foams. By image-based finite element (FE) analysis using X-ray CT images corresponding to the tensile tests on ADC12 foams, it was shown that the fracture path of ADC12 foams observed in tensile tests and the regions of high stress obtained from FE analysis correspond to each other. Therefore, it is considered that the fracture behavior of ADC12 foams in relation to their pore structure distribution can be investigated by image-based FE analysis.     

FSP改性TiNbTaZr/Zn的表征和成骨诱导活性评价

目的: 探讨搅拌摩擦处理加工后的Ti-35Nb-2Ta-3Zr/ Zn（TNTZ/ Zn）复合材料是否具备诱导成骨的生物活性。方法: 通过搅拌摩擦处理,将Zn添加到TNTZ合金表面,设计对照组为TNTZ（未经FSP的TNTZ）,实验组为FSP（未加Zn加工的TNTZ）、TNTZ/Zn-0.5（0.5 mm预制孔）和TNTZ/Zn-1（1 mm预制孔）。使用扫描电子显微镜、X线衍射进行表征分析,检测共培养的大鼠骨髓基质干细胞（bone marrow stromal stem cells,BMSCs）的碱性磷酸酶（ALP）活性,实时定量 PCR 检测ALP活性,COL-1α、OPN和OCN基因的表达。采用 SAS 8.2软件包对数据进行统计学分析。结果: TNTZ/Zn-1组表面Zn纳米粒子分布较均匀,直径为70~80 nm。与TNTZ组相比,TNTZ/Zn-0.5和TNTZ/Zn-1组的ALP表达显著上调（P<0.05和 P<0.01）。相比于TNTZ组,TNTZ/Zn-0.5和TNTZ/Zn-1组的ALP活性、COL-1α、OPN和OCN基因表达增加,差异有统计学意义（P<0.05）。结论: 通过FSP成功将Zn整合到TNTZ合金表面,制备出纳米级微观结构。TNTZ/Zn复合材料可有效诱导成骨,是一种潜在的种植体材料。     

南葶苈子及炒南葶苈子标准饮片的均匀化方法研究

[目的] 对南葶苈子及炒南葶苈子制备标准饮片的最佳均匀化工艺进行筛选。[方法] 以出粉率、黄酮类化合物的总含量（槲皮素-3-O-β-D-吡喃葡萄糖-7-O-β-D-龙胆双糖苷、槲皮素-3-O-β-D-吡喃葡萄糖苷和异鼠李素-3-O-β-D-吡喃葡萄糖）、指纹图谱总峰面积作为指标设计L₉（3⁴）正交实验,对投料量、单次粉碎时间、粉碎次数3个因素进行考察,优化南葶苈子和炒南葶苈子制备标准饮片的均匀化方法。[结果] 南葶苈子最佳均匀化工艺：投料量150 g,单次粉碎时间10 s,粉碎4次;炒南葶苈子饮片最佳均匀化工艺：投料量100 g,单次粉碎时间10 s,粉碎3次。[结论] 通过正交实验得到的均匀化工艺方法得当,合理可行,为南葶苈子及炒南葶苈子制备标准饮片进行质量控制研究提供参考,为标准饮片均匀化技术规范制定提供了科学依据。     

基于色彩色差计的川楝子炮制前后含量和颜色变化

目的:建立了川楝子药材中川楝素含量的高效液相方法,采用在线式非接触红外控温炒药机炒制川楝子,比较川楝子炒焦前后川楝素的含量变化及药材颜色变化.方法:采用色彩色差计测量炒焦前后药材颜色变化;采用色谱柱为Wondasil C18柱,甲醇-水(1:1)为流动相,检测波长为217 nm,测定川楝素.结果:川楝素平均回收率为10...     

不同处理工艺对真空油炸毛豆品质的影响

研究了2种预处理工艺结合真空油炸对毛豆水分质量分数、脂肪质量分数和色差的影响.结果表明,与冷冻预处理和直接油炸(对照)相比,预干燥可以有效地降低毛豆的脂肪质量分数,且没有显著性地影响毛豆的色泽(P>0.05).随着前期热风预干燥时间的延长,真空油炸后毛豆的水分与脂肪质量分数逐渐减小,毛豆油炸干燥速度逐渐降低;另一方面,随着真空油炸时间的延长,毛豆自由水分逐渐减少,其后期干燥速率也逐渐降低.