Damage detection method in complicated beams with varying flexural stiffness

A damage detection method for complicated beam-like structures is proposed based on the subsection strain energy method (SSEM), and its applicability condition is introduced. For a beam with the continuously varying flexural stiffness and an edge crack, the SSEM is used to detect the crack location effectively by numerical modal shapes. As a complicated beam, the glass fiber-reinforced composite model of a wind turbine blade is studied based on an experimental modal analysis. The SSEM is used to calculate the damage index from the measured modal parameters and locate the damage position in the blade model successfully. The results indicate that the SSEM based on the modal shapes can be used to detect the damages in complicated beams or beam-like structures for engineering applications.     

Spectral responses of GaAs photodiodes fabricated by rapid thermaldiffusion

The spectral responses of GaAs photodiodes fabricated by rapid thermal diffusion (RTD) of Zn are presented. The authors tried controlling the p⁺-n junction depth by the heating rate of RTD, without extending the diffusion time. It is found that Zn diffuses from the surface to a deeper position as the heating rate increases. Consequently, the spectral response of photodiodes formed by RTD is strongly dependent on the heating rate of RTD. A large improvement in the short-wavelength response between 400 and 800 nm is observed as the heating rate decreases     

提高金属材料离子注入效益的一条新途径

本文评述了在金属材料领域中应用离子注入技术的现状;阐明了提高离子注入效益的一条新途径:不仅以离子注入技术改变工模具的性能,延长其使用寿命,而且以离子注入技术来显著提高金属产品的质量。文末还对进一步发展离子注入的前景做了展望。     

信噪比时变情况下的自适应时延估计方法

本文介绍了一种自适应时延估计的改进方法，此方法用于在信噪比时变情况下，对空间上分离的两个传感器所接收的带限信号的时延估计。它的优点在于：当信噪比变化或未知时，它能对时延的变化随时做出估计。文中给出了此方法的估计精度和收敛特性。     

Properties and design theory of ultrafast GaAsmetal-semiconductor-metal photodetector with symmetrical Schottkycontacts

A GaAs metal-semiconductor-metal photodetector fabricated in a symmetrical and interdigital Schottky contact structure on a semi-insulating GaAs substrate is discussed. The device exhibits a high-speed response and a very low dark current, even with a moderate size (200 μm²). Ultrafast responsivity is due to the high drift velocity of the photoelectrons and low capacitance. A design theory for optimum performance which includes a compromise between the circuit time constant and the transit time is described     

The vapor phase oxidation of 3-picoline on tin and titanium vanadates

The oxidation of 3-picoline with air on fused tin and titanium vanadates gives as the main reaction products nicotinaldehyde and nicotinic acid, the yield of which amounts to 45–50% of theory calculated on the alkylpipidine taken and 75–80% calculated on that which has reacted.Part LXIV of the series Oxidation of organic compounds: for part LXIII, see [1].