TiAl/40Cr扩散焊界面质量的超声评价

采用超声C扫描法对TiAl和40Cr扩散焊界面进行了检测,分别研究了界面回波幅度平均值和标准差与接头抗剪强度之间的关系,并讨论了焊接温度和试样表面粗糙度对上述关系的影响及界面气隙长度与回波幅度的关系.结果表明,当试样表面粗糙度一致时,回波幅度平均值和标准差随着抗剪强度的降低而增加.表面粗糙度会影响回波幅度平均值和标准差与接头抗剪强度的关系.当空气间隙的长度小于400 μm时,回波幅度与空气间隙长度近似成正比例关系.     

超声冲击对焊接结构残余应力的影响

以Q345钢结构箱型柱为对象，研究了超声冲击工艺对焊接残余应力的影响。对电渣焊和埋弧焊两种焊缝进行了超声冲击试验，其中埋弧焊焊缝采用了全覆盖冲击和焊趾冲击两种冲击工艺。残余应力测量表明，采用冲击工艺，可以在焊缝表面一定深度(小于3mm)下产生压应力，最高测得-134MPa；焊趾冲击不但使焊趾表面产生压应力，也降低了焊缝的残余应力。对非熔透埋弧焊和熔透埋弧焊焊缝的测量结果显示，在盲孔法测量的深度范围内，超声冲击可降低焊缝最大主应力约34％～55％。     

SiC FIBER／ALUMINIUM PREFORM WIRES FABRICATEDBY ULTRASONIC LIQUID INFILTRATION PROCESS

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Effect of ultrasonic power and bonding force on the bonding strength of copper ball bonds

Copper wire, serving as a cost-saving alternative to gold wire, has been used in many high-end thermosonic ball bonding applications. In this paper, the bond shear force, bond shear strength, and the ball bond diameter are adopted to evaluate the bonding quality. It is concluded that the ef/~cient ultrasonic power is needed to soften the ball to form the copper bonds with high bonding strength. However, excessive ultrasonic power would serve as a fatigue loading to weaken the bonding. Excessive or less bonding force would cause cratering in the silicon.     

不等厚板过渡削薄对接焊缝的超声波探伤

不等厚板经过渡削薄处理后的对接焊缝,由于厚度的不均匀,射线穿透时的衰减不一样,对射线检测带来很大的麻烦。常用的超声波探伤方法在定位和定级方面比较困难,本文给出利用现在先进的数字式超声波探伤仪进行准确探伤的方法。     

原位聚合法研制纳米胶囊相变材料

采用超声波工艺及细乳液原位聚合方法,研制了以聚苯乙烯为囊壁、正十八烷为囊芯的纳米胶囊相变材料;系统探讨了聚合反应各因素如引发剂、链转移剂、表面活性剂以及正十八烷/苯乙烯比等对乳胶粒子的形态、胶囊材料热性能的影响,对所研制的胶囊相变材料进行激光衍射粒度分析、透射电镜及差示扫描量热等表征.实验结果表明,在引发剂AIBN 0.5%(油相质量百分比,下同);链转移荆DD在T0.4%;复合乳化剂(SDS/OP10)总量2%,配比1:1及正十八烷/苯乙烯比=1:1条件下,胶囊呈球形均匀分布,聚苯乙烯囊壁能将正十八烷囊芯很好包裹住,其胶囊Z均直径124nm,相变焓可达124.4kJ·kg-1.     

超声提取-高效液相色谱法测定烟草中烟碱含量

确定了制备烟碱分析样品的超声波提取条件:0.4% NaOH溶液为溶剂,液固比40:1(mL·g-1),提取时间4 h.确定了高效液相色谱法检测烟碱含量的条件为Kromasil C18色谱柱(250 mm×4.6 mm,5 μm),检测波长259 nm,检测温度35 ℃,流动相CH3OH/0.02 mol·L-1磷酸盐缓冲溶液(V/V)为60/40,流速1.0 mL·min-1,进样量10 μL.平均加样回收率98.8%,相对标准偏差1.2%.结果表明超声提取-高效液相色谱法是一种准确度高,速度快的测定烟草中烟碱含量的检测方法.     

超声波对沉淀二氧化硅的分散解聚研究

研究了超声波对沉淀二氧化硅的分散解聚效果，实验证明，当频率为40kHz，功率密度达到1．8W/cm^2时，沉淀二氧化硅浆料可以获得极佳的分解效果，二氧化硅聚集体小于77．6nm的颗粒数量达98．9％。     

当归挥发油的提取与成分分析

采用常压水蒸汽蒸馏法、超声波提取法、微波提取法提取当归挥发油,实验表明采用微波提取法在微波功率720 W、萃取时间120 s、100 mL环己烷中的收率最高,为1.04%.并采用GC-MS联用技术对3种方法提取到的挥发油进行了成分和含量分析,主要成分是当归的活性成分藁本内酯.     

Dis-Bond Detection and the Possibility of Interfacial Stiffness Measurement with Real-Time Impulsive Stimulated Thermal Scattering

We describe a new, real-time, noninvasive method for dis-bond (delamination) detection which is based on a technique known as impulsive stimulated thermal scattering (ISTS). We first explain the ISTS technique and compare data from polyimide films tightly bound to silicon substrates with data from unsupported polyimide films. The observed differences in the data from these two cases are readily understandable and offer an unmistakable signature for delaminations. We demonstrate ISTS dis-bond detection by locating and mapping out randomly-distributed and spatially-fine regions of delamination in a polyimide film-silicon substrate system. Finally, we present two simple physical models of the interfacial region which comprehensively describe acoustic data from the tightly-bound and the unsupported samples. With insight from simulations using these models, we suggest how ISTS might be used to determine interfacial adhesion quality and we show how ISTS sensitivity to interfacial effects can be adjusted.