细铜棒内部缺陷超声自动检测系统设计

目的 检测细铜棒内部缺陷。方法 采用组合超声检测法，结合多探头数据融合技术。结果 实现了细铜棒内部缺陷的定性、定量自动检测。结论 利用组合超声法和数据融合技术可以提高细铜棒的检测精度。     

细铜棒内部缺陷超声自动检测系统设计

目的　检测细铜棒内部缺陷 .方法　采用组合超声检测法 ,结合多探头数据融合技术 .结果　实现了细铜棒内部缺陷的定性、定量自动检测 .结论　利用组合超声法和数据融合技术可以提高细铜棒的检测精度 .     

厚壁管超声探伤方法研究

厚壁管超声探伤方法研究北京航空材料研究院韩波，李家伟一般来讲，管材内部缺陷的分布方向主要有两种，即径向和轴向。轴向缺陷的检验采用纵波直探头或双晶探头即可解决。径向缺陷的检验，对于壁厚与外径之比小于０．２的管材而言，可采用纯横波检测；壁厚与外径之比大于...     

纵波脉冲回波法和兰姆波法在表征薄层结构中的应用比较

介绍了两种常用的材料薄层超声表征方法——纵波脉冲回波法和兰姆波法。阐述了其基本原理，并结合实例比较了它们的应用情况、优缺点和适用条件等。纵波脉冲回波法简单易行，能够获得薄层厚度、声速和衰减等信息。但实验结果受薄层介质的声衰减和表面粗糙度影响较大，对探头的性能要求较高。兰姆波法主要用于表征薄板类材料，无需较高检测频率，可以测得板中纵波和横波的声速、板厚和板与板之间的结合特性等，检测精度较高。缺点是发射和接收探头之间的距离和倾斜角度需要严格控制，影响因素较多。     

碳纤维/树脂基复合材料薄板的超声波检测

针对碳纤维/树脂基复合材料层压板在航空航天运用中的实际特点,分析了碳纤维/树脂基复合材料层压板的缺陷特征,选择纵波垂直反射法作为检测手段,提出了调整探头晶片后面阻尼块的阻尼系数和在探头前面增加软性透射膜水囊结构等改进超声探头的方法,有效地提高探测信号可识别性和减小探测盲区,有利于用反射信号的相位特征及形状来对缺陷进行定性分析.试验表明,改进后的纵波垂直反射法方便实用,操作性强,能有效地对碳纤维/树脂基复合材料层压板进行缺陷检测.     

基于证据理论的超声粘接检测的数据融合

目的 研究超声粘接检测的数据融合方法。方法 采用D－S证据理论。结果 提出了利用纵波、横波、板波等不同的超声探头检测金属与非金属粘接状态的融合方法,并进行了验证分析。结论 提出的方法是可行的。     

互易法校准压电型声发射传感器的研究与实现

声发射传感器的校准是实现声发射定量技术的前提,依据电声换能器互易原理,在计算互易常数的基础 上,建立了适用于压电型声发射传感器表面波和纵波互易的校准系统。通过设置特定的激励信号波形,依据接收 电压信号与激励电流信号之间的时间延迟,准确获取电流信号与电压信号对应的特征值,实现了声发射传感器的表面波和纵波互易校准。由于传感器的尺寸效应,传感器在高频时的表面波速度灵敏度低于纵波灵敏度,不确定度评定结果表明,声发射传感器速度灵敏度的互易法校准不确定度为1. 2 dB。     

钢轨服役疲劳特性的非线性表面波检测研究

该文利用非线性表面波检测方法对钢轨在不同服役年限后的疲劳特性进行评价,通过推导得到表面波相对非线性系数的测量表达式,选取服役期为0、1、2、5、10和20年的钢轨,采用楔块探头研究非线性表面波在钢轨截面传播特性,以此分析表面波非线性系数的规律。实验结果显示服役初始阶段钢轨的非线性系数的变化很小,随着服役时间的增加钢轨非线性系数变化速率呈现增大的趋势;通过对钢轨微观组织分析,表明位错密度增加所导致的微裂纹是钢轨的非线性系数增大的重要原因。研究将为非线性超声检测钢轨服役疲劳损伤提供理论依据,对预防钢轨因疲劳导致的失效,保证钢轨的安全服役和铁路运行安全提供新的研究方向。     

钢锻件的超声波纵波手动检测工艺的优化

钢锻件超声波手动检测时,其工艺类似钢板纵波检测,但锻件厚度较大,不易确定其缺陷位置,也不易确定其当量。本文对此工艺进行了优化：包括对超声波检测仪器、试块、探头的选择、直探头偏离的测定、检测时机和表面准备、方向、灵敏度的确定校准和复核、手动扫查方法、灵敏度补偿、缺陷当量确定、记录和评级等。     

基于PC的水浸式全数字化多通道自动超声波探伤系统

为检测厚壁无缝钢管中存在的缺陷,保证厚壁无缝钢管的质量,在分析厚壁无缝钢管的超声波探伤原理的基础上,设计并开发一套基于PC微机的厚壁无缝钢管水浸式全数字化多通道自动超声波探伤系统。采用双通道脉冲反射式纵波直探头检测厚壁管纵向、横向内外壁缺陷,扫描方式选取探头固定钢管螺旋前进的方式。现场实验表明:系统能准确检测出厚壁无缝钢管中存在的缺陷,性能满足设计要求。     

Effect of Electron Beam Orientation on Exit Wave Function via Simulation of Electron Dynamic Diffraction

Based on the electron dynamic diffraction, phase shift of the exit wave function vs misorientation of the incident electron beam from the exact zone axis has been calculated for the [001] oriented copper. The result shows that the peak of phase shift is the maximum at the atom position as the electron beam along the exact [001] zone axis, and the peak value of phase shift decreases as increases of the misorientation. At small misorientation, i.e. less than 5 degree, change of the phase shift is minimal. The peak value of phase shift decreases significantly when the incident beam deviates form the zone axis over 10 degree and the exit wave has a planar configuration as the misoriention angle arrives -17 degree. The effect of this phase shift characteristics on the information extracted from the hologram has also been considered.     

Nanostructured copper and copper oxide thin films fabricated by hydrothermal treatment of copper hydroxide nitrate

Metallic copper and copper oxide thin films were fabricated on surface of glass slide substrates. Copper oxide thin films were prepared by a hydrothermal method using an α-phase layered hydroxide, copper hydroxide nitrate as a precursor. Morphology, thickness and crystallite size of the obtained copper oxide thin films changed by changing the time of hydrothermal treatment. Accordingly, the copper oxide thin films showed various water contact angles and optical band gaps. As, the optical band gap of the nanostructured copper oxide thin films increased with an increase in hydrothermal time from 1.85 to 2.95 eV. Moreover, the water contact angles changed from 16.4 to 38.8° by changing the hydrothermal time. By a reductive hydrothermal-treatment route, the copper oxide thin film was reduced to metallic copper thin film without any particle growth.     

电沉积铜薄膜中的内应力与织构特征

利用X射线衍射方法分析了电沉积铜薄膜的内应力及其织构特征.结果表明,随薄膜厚度的增加,薄膜内应力增大.电沉积铜薄膜具有较强的(220)丝织构,随着铜薄膜内应力的增加,(220)丝织构增强,同时叠加有板织构的特征.     

Effects of substrate temperature on the surface of polymer thin films prepared by R.F. sputtering with a polyimide target

In this study, we characterized polymer thin films deposited by a conventional radio frequency sputtering apparatus introduced into argon and nitrogen gases with a polyimide target onto copper substrates.Heating effects due to heating the copper substrate at 250 °C in the sputtering on tribological and adhesion properties of thin films were investigated with measuring friction coefficient, wear durability and pull strength. Surface roughness of the nitrogen sputtered thin film decreased by the heating. Friction coefficient of argon and nitrogen sputtered thin films prepared at 250 °C was almost the same level as that prepared at room temperature, respectively. Wear durability of these thin films and adhesion strength between these thin films and copper substrate decreased by the heating.     

Effect of crystal structure on photoinduced superhydrophilicity of copper grafted TiO2 nanostructure thin film

In this work, copper grafted titanium dioxide (rutile and brookite) thin films were deposited on glass substrates using the dip-coating method. Field emission scanning electron microscopy and X-ray photoelectron spectroscopy were used to evaluate the surface morphology and properties of the film surfaces. The water contact angle on the film surfaces during irradiation and storage in a dark place was measured by a contact angle analyser. The results indicate that copper grafted titanium dioxide brookite thin film showed higher hydrophilicity than copper grafted titania rutile thin film.     

In situ study of thin film growth by internal stress measurement under ultrahigh vacuum conditions: Silver and copper under the influence of oxygen

The internal stress of thin silver and copper films was determined during and after evaporation under ultrahigh vacuum conditions. In contrast with silver the residual stress of copper films was strongly affected by the partial oxygen pressure during the metal deposition. We therefore used copper films, dosed with oxygen either during or after deposition, as substrate films for the deposition of a second copper film to study the influence of the physical and chemical properties of the substrate on the internal stress of copper. It was demonstrated in this study that internal stress measurements can make an extremely valuable contribution towards the characterization of thin film growth if combined with a model for the origin of this internal stress. Furthermore, it was demonstrated that this technique can also be used to study the effect of gas adsorption on the internal stress of thin films.     

Electrochemical characterization of carbon nanotube forests grown on copper foil using transition metal catalysts

Growth of vertical, multiwalled carbon nanotubes (CNTs) on bulk copper foil substrates can be achieved by sputtering either Ni or Inconel thin films on Cu substrates followed by thermal chemical vapor deposition using a xylene and ferrocene mixture. During CVD growth, Fe nanoparticles from the ferrocene act as a vapor phase delivered catalyst in addition to the transition metal thin film, which breaks up into islands. Both the thin film and iron are needed for dense and uniform growth of CNTs on the copper substrates. The benefits of this relatively simple and cost effective method of directly integrating CNTs with highly conductive copper substrates are the resulting high density of nanotubes that do not require the use of additional binders and the potential for low contact resistance between the nanotubes and the substrate. This method is therefore of interest for charge storage applications such as double layer capacitors. Inconel thin films in conjunction with Fe from ferrocene appear to work better in comparison to Ni thin films in terms of CNT density and charge storage capability. We report here the power density and specific capacitance values of the double layer capacitors developed from the CNTs grown directly on copper substrates.     

Sputter deposition of ZnO nanorods/thin-film structures on Si

Using a recently developed sputter deposition technique, ZnO deposits were grown at the room temperature on silicon wafers with various kinds of copper surface layers. The copper layers were prepared using sputter deposition, thermal evaporation, or electroless plating technique. It was found that the surface copper prepared using both sputter deposition and thermal evaporation technique grew only ZnO thin films, while the surface copper prepared using sputter deposition technique grew ZnO nanorods/thin-film deposits. The relation between the copper characteristics and the growth of ZnO nanorods/thin-film deposits was investigated. The growth kinetics of the ZnO nanorods/thin film structure is also discussed.     

细长轴车削加工工艺方法探索

为了解决细长轴类零件在加工过程中所存在的问题,本文以典型轴类细长轴零件为例对其加工方法进行了较为全面的分析,并总结出一些实际可行的加工方法,通过对刀具材料的分析,切削参数的控制,有效控制了加工中变形现象的产生,为同类细长轴零件加工提供了借鉴.     

The aging effect of the thermoelectric power of thin copper films

The thermoelectricpower, referenced to bulk copper, of thin films of copper about 150 Å thick was measured by preparing a thin film bridge between two copper wires which served as leads. This arrangement produces two junctions between the thin film copper and the bulk copper. The two junctions were maintained at a temperature difference which was measured using a calibrated copper-constantan thermocouple. It was found that the thin film-to-bulk thermoelectric power varies with time and can be fitted to an equation of the form

$\text{S = S}{}_{\mathrm{<mtext>F</mtext>}}\text{(1?}\text{e}{}^{\mathrm{-\lambda t}}\text{)}$

where λ depends on temperature. The constant λ in the equation has values very close to those found from thin film resistance aging measurements, suggesting that the same mechanism is responsible for both aging phenomena. The heated junctions is negative, in agreement with a simple electron diffusion model of thermoelectric power.