中频脉冲磁控溅射制备氮化铝薄膜

使用中频脉冲磁控溅射技术分别在Si（111）、玻璃以及高速钢基底上沉积A1N薄膜，利用X射线衍射、X射线光电子谱、扫描电镜、紫外荧光、FTIR、精密阻抗分析仪等研究了薄膜的结构、光学及电学性质，结果表明，生成的（002）取向多晶A1N薄膜在可见光区域平均透过率超过75％，在紫外区域也具有较高的透过经，在低频交流区域具有良好的绝缘性。     

发展中的我国中学物理"四个类型实验"

分析总结了半个世纪来我国中学物理教学“4个类型实验”的历史、内涵、功能和教法。     

Weak Barriers in Nonlinear Potential Theory

We characterize regular boundary points for p-harmonic functions using weak barriers. We use this to obtain some consequences on boundary regularity. The results also hold for -harmonic functions under the usual assumptions on , and for Cheeger p-harmonic functions in metric spaces.      

具有域内支承的中厚板的边界元法分析

本文借助简化的Reissner理论,利用边界元法对具有域内支承的中厚板进行了分析。建立了相应的边界积分方程,导出了各基本解,讨论了域内支承柱对板的支承情况,编制了计算程序并给出部分算例。     

A phenomenological model of electrorheological fluids

The fundamental assumption of the paper is that the extra stress tensor of an electrorheological fluid is an isotropic tensor valued function of the rate of strain tensor D and the vector n (which characterizes the orientation and length N of the fibers formed by application of an electric field). The resulting constitutive equation for is supplemented by the solution of the previously studied time evolution equation for n. Plastic behavior for the shear and normal stresses is predicted. Anticipating that the action of increasing shear rate is i) to orient the fibers more and more in the direction of flow and ii) simultaneously to break up the fibers leads to the conclusion that for the same behavior is encountered as without an electric field. Using realistically possible approximation formulas for the dependence of and N on leads to the Bingham behavior for and power law behavior for large shear rates.

骨导超声听觉感知综述

通过骨导振动,人耳能够产生超声听觉感知,从而颠覆了人耳听不到超声的传统概念。对骨导超声感知研究领域国内外发展历程进行系统介绍,着重分析并探讨了三大研究热点:骨导感知的基本特点、人耳主观感知声以及感知机制的阐明,为后续的研究工作奠定了基础。     

An improved and provable self‐certified digital signature scheme with message recovery

This paper presents a self‐certified digital signature scheme with message recovery that is proven to be secure. So far, many schemes of this kind have been proposed to keep message secret in the transmission. But Zhang et al. has proposed the man‐in‐middle attack to Shao's self‐certified signature scheme, which is based on discrete logarithm. The attacker can make a new signature by using an old one, but the reason of such man‐in‐middle attack was not referred. We present the scheme of Yoon et al., which is also based on discrete logarithm, that cannot resist man‐in‐middle attack either, give the analysis of the attack, and propose a new scheme. The proposed scheme can resist forgery attack in the random oracle model and avoid message leakage, the man‐in‐middle attack, and meanwhile has several security characters. Compared with some self‐certified schemes, our scheme is the best because of the time cost. Copyright © 2013 John Wiley & Sons, Ltd.     

基于小波分频的压电式人工中耳信号处理研究

基于一新型压电式人工中耳,提出利用小波分频方法对其信号进行处理,使该植入装置能模拟正常中耳的传递特性.首先,基于Bark频谱理论,利用小波分频技术将输入信号分为17个频带;再参考中耳传递特性,对每个频带的信号赋以相应的增益系数;最终,通过实验验证该方法的可行性.结果表明,该法可使压电叠堆的输出能较好地反应正常中耳的传递特性.     

Coating of titanium implant materials with thin polymeric films for binding the signaling protein BMP2

A fast and simple approach for immobilization using copolymers as interlayers is reported. The synthesized copolymers form stable self-assembled layers on implant materials like, e.g., titanium in a simple coating/drying/washing sequence and have functional groups which can bind proteins from an aqueous solution. The copolymer films have been characterized via ellipsometry and contact angle measurements and were tested for biocompatibility. An immunoassay was used to determine the amount of BMP2 and demonstrated an approximately 10-fold increase as compared to previously used self-assembled monolayers. A BMP2-responsive cell line with luciferase detection was used to determine the biological activity of the bound signaling protein.     

Optimum selection of the dental implant diameter and length in the posterior mandible with poor bone quality – A 3D finite element analysis

This study aimed to evaluate continuous and simultaneous variations of dental implant diameter and length, and to identify their relatively optimal ranges in the posterior mandible under biomechanical consideration. A 3D finite element model of a posterior mandibular segment with dental implant was created. Implant diameter ranged from 3.0 to 5.0 mm, and implant length ranged from 6.0 to 16.0 mm. The results showed that under axial load, the maximum Von Mises stresses in cortical and cancellous bones decreased by 76.53% and 72.93% respectively, with the increasing of implant diameter and length; and under buccolingual load, by 83.97% and 84.93%, respectively. Under both loads, the maximum displacements of implant-abutment complex decreased by 58.09% and 75.53%, respectively. The results indicate that in the posterior mandible, implant diameter plays more significant roles than length in reducing cortical bone stress and enhancing implant stability under both loads. Meanwhile, implant length is more effective than diameter in reducing cancellous bone stress under both loads. Moreover, biomechanically, implant diameter exceeding 4.0 mm and implant length exceeding 12.0 mm is a relatively optimal combination for a screwed implant in the posterior mandible with poor bone quality.