Problems of nondestructive testing of wheel-pair components of rolling stock

Improving the effectiveness of nondestructive testing of railway rolling stock’s wheel-pair components during their manufacturing and repair is considered. The results of metallographic studies of PY-1 and PY-1III solid-rolled wheels and axles, analysis of the operating specifications, and experimental studies of the optimal methods of nondestructive testing are included.     

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Cleaning Procedure for Single-Crystal Tungsten Substrates

Single-crystal tungsten substrates produced by electron-beam melting were cleaned by annealing in an oxygen atmosphere (10^–3Pa, 1500°C) for a few hours to remove adsorbed carbon and by high-temperature ultrahigh-vacuum annealing (2 × 10^–8Pa, 2500°C) for a few minutes to remove residual oxygen. The process was followed by low-energy ion scattering, Auger electron spectroscopy, and low-energy electron diffraction. The carbon and oxygen adsorbed on the surface of single-crystal tungsten were found to form ordered, oriented structures. The resultant high-purity, structurally perfect W substrates were used to study electron emission in the Ba/W and Re/W systems.     

Investigation of Scattering of Transverse Waves by Crack

The paper compares experimental and theoretical investigations of transverse waves scattered by a narrow vertical slit imitating a crack, which are generated and detected by separate slanted transducers.     

A poor substitute

The notch is a commonly used type of fabricated flaw in ultrasonic testing of welded joints of small and intermediate thicknesses. The tale is about how some experts attempted inconsiderately to do without it and what resulted from this.     

On a peculiarity of low-energy ion scattering from a well-ordered bcc W(2 1 1) surface

A peculiarity in the backscattering of keV He⁺ ions by a well-ordered high-purity W(2 1 1) surface is reported. Besides the normal elastic binary collision peak and the low-energy tail due to backscattering in deeper layers, an extra peak is observed for an inelastic loss of about 95 eV. This unusually large loss has a constant value over a wide range of primary energies (1.5-4.5 keV). An extra peculiarity is that the peak is only observed for the scattering in normal incidence towards the (2 1 1) plane. It is also not seen for polycrystalline W. The energy loss may be due to a quasi-double or -triple collisions of He particles with the row-trough structure of W(2 1 1) involving electronic excitation of both He and W atoms. Alternatively it may be due to a special channeling/dechanneling process for the incident ions.     

Calculations for pulses transmitted through thin layers

Computer simulations have shown that the energy of an ultrasonic pulse transmitted through a thin liquid layer is almost independent of the layer thickness over a relatively wide range.     

These Books Must Have Each Serious Specialist on Nondestructive Testing

Russian Journal of Nondestructive Testing -     

MEMS助力推动下一代无线通信

未来的无线通信系统将具备各种新功能并高度微型化。而且,3代和4代多模/多波段无线终端设备将为新业务、互联网与Mcommerce(移动电子商务)数据、以及静态/视频图象提供网络连接。此外,终端设备也应具备更多新功能来吸引更多终端用户。微电子 机械(microelectromechanical,MEM)元件与系统可提高创新性3代产品的集成化水平,并可调整器件的特性和工作方式,因此可降低3代 图 产品的尺寸和成本。它们还将为 　　　无线系统带来新的体系结构和功耗管理特征。此外,MEMS还将推动新功能、传感器、执行器在无线终端设备上的集成。用户接口需要采用新的技术解决方案。微机械传感器和麦克风已经有元件形式的产品,它们可以被看作是更复杂、包括若干集成化传感器元件的智能系统的一个组成部分。对移动终端来说,娱乐和游戏功能是新功能开发的重要推动力,传感器和执行器也是如此。微反射镜和微透镜为照相机和显示器的实现带来了新的可能,如投影显示。因此MEMS将极大地促进未来无线系统的发展。本文将对 MEMS 在无线通信发展 中的应用进行探讨,首先讨论微系统 化、多功能器件在紧凑系统中的集成、...