LMG的沟槽结构对静刚度影响的研究

滚动直线导轨副目前主要有单圆弧和双圆弧两种沟槽形式。在介绍这两种沟槽结构的同时分析其特点,通过有限元建模的方法建立其对应的数值模型,利用ANSYS软件仿真计算对应结构的受力、变形并分析在不同预紧力和外载荷时刚度的大小和变化规律,为更合理地选用不同形式沟槽的滚动直线导轨副提供一定的依据。     

Facile method to prepare a novel honeycomb-like superhydrophobic Polydimethylsiloxan surface

A novel honeycomb-like superhydrophobic Polydimethylsiloxan surface with interesting hierarchical micro- and nanostructures was obtained using a facile template method. The water contact angle and sliding angle of the superhydrophobic Polydimethylsiloxan surface were 155 ± 1.7° and 5°, respectively. The superhydrophobic Polydimethylsiloxan surface showed high stability in the pH range from 1 to 14. After several frictions, the superhydrophobic Polydimethylsiloxan surface also maintained high superhydrophobicity. When the superhydrophobic Polydimethylsiloxan surface was contaminated, 99.5% contaminant particles were removed from the superhydrophobic Polydimethylsiloxan surface by artificial rain, showing an excellent self-cleaning property. After being stored in an ambient environment for 6 months, no decrease in water contact angle was observed.     

Advances in DLC coatings by hybrid PSII and PECVD as a barrier to corrosion in simulated body fluid*

In this study, diamond-like carbon (DLC) films were deposited on biomedical AISI316L stainless steel by hybrid plasma source ion implantation (PSII) and plasma-enhanced chemical vapour deposition (PECVD). Potentiodynamic polarization tests and Electrochemical Impedance Spectroscopy (EIS) have been employed to investigate the corrosion performance of different DLC films in Tyrode's simulated body fluid (pH = 7.4). The corrosion resistance of the DLC films by PECVD deteriorated rapidly after 24 h of immersion, but those made by hybrid PSII and PECVD offered more effective barrier for AISI316L stainless steel during 72 h of immersion. The test results demonstrated that the DLC film by hybrid PSII and PECVD possessed less corrosion current density, greater corrosion resistance, and more positive breakdown potential in simulated body fluid.     

Influence of α Phase on Shape Memory Effect and Superelasticity of CuZnAI Alloy

The influence of a small amount of α phase inβ′ matrix on shape memory effect andsuperelasticity of CuZnAl shape memory alloy hasbeen studied systematically.It has been found thattransformation temperature can be adjusted in alarge scale by controlling the amount of α phase,meanwhile,shape memory effect and superelasticitydo not decrease obviously when there exists a smallamount of α phase.Based on the optical and trans-mission electron microscopy observation,the influ-ence of α phase on shape memory effect andsuperelasticity has been discussed.     

Structural characteristics of rutile films prepared by direct deposition and neon ion beam assisted deposition

In this article, titanium dioxide films prepared by neon ion beam assisted deposition (IBAD) in an oxygen environment were investigated. The deposition rate was varied from 0.2 to 0.4 nm/s while the current density and ion energy were kept at 20 μA/cm² and 40 keV. The structural characteristics of all films were studied by X-ray diffraction and Raman spectroscopy. Results show that all the films exhibit a rutile phase. The location of (2 0 0) diffraction peaks deviated from the standard value. Simultaneously, the relative intensity of (2 0 0)/(1 1 0) peaks decreases with increasing evaporation rate. All results are discussed in terms of surface free energy and ion channeling effects.     

Temperature dependence of Kt, in piezoelectric ceramics near F-AF phase boundary

The temperature dependence of the electromechanical coupling factor K_t in PLZT and PSZT ceramics with the composition situated near the ferroelectric(F) and antiferroelectric(AF) phase boundary is investigated. The results show that the value of K_t is connected with the F-AF phase boundary. The K_t, in PLZT ceramics drops down with the increase of temperature which makes the measured site depart from the F-AF phase boundary. The K_t in PSZT ceramics increases with the increase of temperature which makes the measured site close to the F-AF phase boundary. It is possible to develop the piezoelectric ceramic materials with good temperature stability by means of the choice of composition with the proper F-AF phase boundary.     

多级离心式压缩机小流量系数叶轮的内流特点和设计方法

本文从计算叶轮侧壁三元粘性边界层出发，分析了多级离心式压缩机后级经常用的小流量系数窄叶轮的内流特点，提出了一种预定叶片力的分布并求解动量积分方程的反问题设计方法。数值试验和对比分析证明了这一方法的合理性。在此基础上，对目前工业上应用的不同类型和特点的小流量系数叶轮进行了分析和评述。     

Internal Friction in a Shape Memory Alloy Cu-Zn-Al under Equilibrium Condition

1. Introduction CuZnAl shape memory alloys have beenextensively studied as a new type of material.Dejonghe[1]et al. firstly reported theirresults on the internal friction (IF) of CuZnAlalloys in 1975. Later, some researchershave done much work on internal friction.But most of them were concerned withphase transformation internal frictionof martensite and reverse martensite andfew of them were about internal friction     

无线通信设备防雷措施探讨

目前无线通信已经被广泛应用于许多领域,但是由于雷电的危害,无线通信设备时刻都处在危险当中。本文探讨了无线通信设备的防雷措施。     

Effect of Co-polyester antistatic agent modified by carbon nanotubes on the properties of polypropylene fibers

Antistatic polymer fibers were investigated by using carbon nanotubes (CNTs) to enhance the antistatic ability of inner antistatic agents based on the mechanism of attracting moisture by polar radical groups. It is indicated that the antistatic ability of the fibers filled with composite antistatic agents that contain CNTs and organic antistatic agents was superior to that of the fibers filled either with pure organic antistatic agents or pure CNTs. The antistatic ability of the composite antistatic agent fabricated by an in situ process was superior to that of the composite antistatic agent fabricated by direct dispersing CNTs in the antistatic agent carrier. Moreover, the heat-treated CNTs could further enhance the antistatic effect compared with the initial CNTs. The antistatic effect is significantly influenced by the content of CNTs in the composite antistatic agent.