钢管减阻型内涂层生产工艺及设备

介绍了钢管减阻型内涂层技术的生产工艺和主要设备，给出了内涂层生产线典型的工艺布置，并对主要设备的组成及工作原理进行了介绍。     

Determination of friction coefficient encountered in large deformation processes

A new technique, namely, the open-die backward extrusion test technique, was developed as an alternative method to the ring compression test in order to quantitatively evaluate the coefficient of friction, μ, at the die/workpiece interface. This technique relates the percentage deformation in height of the specimen to the percentage increase in extruded height of the specimen. In this study, the open-die backward extrusion tests (ODBET) were simulated for different aspect ratios, (H/D), and different die geometries, (d/D), by utilizing an elastic-plastic finite element code (ANSYS) in order to obtain the friction calibration curves (FCCs). The results indicated that the extruded height is related to the friction conditions at the die/workpiece interface. Therefore, ODBET can be used to generate FCCs to determine the coefficient of friction at the die/workpiece interface in large deformation processes.     

AN EXTENDED MODELING OF TIDE-WAVE MOTION

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节能润滑油在KTK-12.5/35氧压机上的使用

对氧压机试用节能润滑油前后的相关参数进行比较,通过计算验证该设备使用此油后的节电率,取得了预期的经济效益。     

Application of the dynamical flexural resonance technique to industrial materials characterisation

The determination of the Young’s modulus and damping coefficient Q⁻¹ by means of non-destructive vibrating techniques has been applied to bulk and coated industrial materials. Extensions of a previous analytic model of composite beam allow to determine accurately the macroscopic modulus of each component of multilayered structural materials as coated superalloys or nitride-hardened steels. Furthermore, the study of glasses and polymers has been investigated. An attempt of normalisation of the modulus versus temperature curves allows to establish master curves depending on the specific structure, from metallic glasses to polymeric glasses. Finally a comparison of dynamical modulus and Q⁻¹ values measured between resonant (>1 kHz) and subresonant techniques (10⁻³ to 10 Hz) in relation to the loading frequencies applied in real conditions has been under folder. For metallic materials such as forged or rolled titanium alloys, the brittle-to-fragile transition occurs abruptly or smoothly with a shift of 300 K following the range of excitation frequencies.     

Friction Stir Welding of Ceramic Particle Reinforced Aluminium Based Metal Matrix Composites

The mechanical and microstructural properties of 6061+20% Al₂O_3p and 7005+10% Al₂O_3p aluminium based metal matrix composites joined by friction stir welding were analyzed in the present study. The two materials were welded into the form of sheets of 7 mm thickness after T6 treatment and were tested in tension at room temperature. The microstructure of the joints was observed by optical microscopy and the fracture surfaces were analyzed by employing a scanning electron microscope equipped with field emission gun in order to study the micromechanisms involved during the deformation.     

基于媒体用户访问行为偏好模型的代理缓存算法

目前,代理缓存技术广泛应用于改善流媒体传输的服务质量.文章从实际用户日志文件的分析出发,利用发现的用户浏览流媒体对象时的行为分布模型,提出了一种新的视频流媒体缓存算法.仿真结果证明,该算法可以通过记录很少的用户访问信息获取较高的性能表现.     

汽车摩擦片厚度测量装置驱动电路的研究

本文通过对摩擦片厚度在线测量装置系统构成的全面分析，对其驱动电路子系统进行了理论探索和技术研究，完成了相应的电路设计、误差分析及器件选择等工作，并进行了具体的实验验证，证明该驱动电路具有良好的性能，可圆满实现摩擦片厚度在线检测和实时分析的工作任务。     

Low Temperature Elastic Constants of Polycrystalline MgB2

We have used a resonant ultrasound spectroscopy technique to measure the bulk and shear modulus of fully dense, polycrystalline MgB₂ between 4 and 300 K. Both moduli show good agreement with published first principle calculations. The internal friction shows a broad maximum around 40 K.     

THE STICKY ISSUES OF DRYING

Unconrolled agglomeration of particles and adhesion of the particulate mass to wall surfaces are common severe problems in many drying operations. This paper reviews the mechanisms of interparticle and particle-surface attraction as well as the theory and the existing tests for characterising powders in terms of internal strength, wall friction and adhesion. The usefulness of the information obtained from these tests in dryer design and operation is critically reviewed. The importance of powder stickiness in various types of dryers is discussed and established methods of combating the problem are presented Recommendations an made for further research in the area of powder cohesion and adhesion.