连轧管“竹节”问题的研究

本文就各工艺参数对“竹节”的影响进行了较系统的试验。在此基础上，对连轧管“竹节”问题进行了分析，得出了“竹节”形态的基本特征；后“竹节”与轧制压力的关系；影响后“竹节”的主要工艺因素等一系列有意义的结果。对前、后“竹节”形态明显不同的原因进行了初步探讨。提出了“竹节”在线控制模型的初步设想。     

铁钴钒软磁合金损耗谱的分形结构

研究了铁钴钒软磁合金的铁芯损耗，发现铁芯损耗谱具有分形结构。讨论了带材厚度和磁感应强度对分形维数Ｄｆ的影响。     

Electroluminescent zinc sulphide devices produced by sol-gel processing

Zinc sulphide thin film electroluminescent devices doped with Mn or Tb have been produced on p-type Si substrates using a process in which doped zinc oxide films are deposited by a sol-gel drain coating method from a solution of zinc acetate containing a manganese or terbium dopant. The films are then converted to ZnS by heating them in an atmosphere containing hydrogen sulphide which replaces the oxygyn with sulphur. The composition, crystalline structure and optical properties of films have shown that complete conversion from the oxide to the sulphide takes place. The luminescent characteristics of the devices so produced have been measured as a function of the doping concentrations, film thickness, insulator thickness and driving voltage and frequency. It has been found that yellow or green luminescence can be obtained using Mn or Tb doping respectively.     

A luminosity monitor system for the JETSET experiment at LEAR

A luminosity-monitor system for the JETSET experiment at LEAR is described. Four silicon-strip detectors are used as position sensitive devices to monitor the elastic p-scattering. The design concept, data-acquisition and results of the detector system are presented. On-line monitoring is used to assure the proper operation of the JETSET experiment.     

Erbium-doped silicon and porous silicon for optoelectronics

Silicon forms the backbone of the microelectronics industry, and possibly, of the optoelectronics industry, hitherto dominated by III/V materials. One of the remaining goals is to build an optical source in silicon. Erbium exhibits luminescent 1.54 μm intra-4f transitions in both silicon and porous silicon. This paper reviews the work which has been carried out in this field and discusses some possible additional applications of erbium-doped silicon in optoelectronics, such as a novel on-chip temperature sensor.     

Structure and Properties of Electroless Ni Deposits

The changes in structure and the hardness of two electroless deposited Ni-P alloy coatings (with P content of 1.5 and 9.5 wt pct) with heat treatment have been studied by XRD and TEM. The deposits containing 1.5 wt pct P can be represented as an fcc NiP supersaturated solid solution of 5~10 nm microcrystallites. whereas the deposits containing 9.5 wt pct P are amorphous. The heat treatment process induces crystallization of amorphous Ni to Ni phosphides and fcc Ni.Both of the deposits reach maximum hardness after annealing at 400℃ for 1 h. All coated steel specimens are inferior in fatigue strength to uncoated steel specimens mainly due to the poor fatigue resistance of the coating itself     

Oxygen absorption kinetics in YBa2Cu3Ox

The oxygen absorption process in highly aligned YBa₂Cu₃O_x samples in air and in pure oxygen was studied at several constant temperatures. The process can be expressed in two steps, a chemical reaction controlled step and a diffusion controlled step. The kinetic equations are as follows respectively:

(1 − a_t) ln(1 − a_t) + a_t = k_Dt

The activation energy was calculated using an Arrhenius equation. The technical conditions of heat treatment for oxygen absorption of highly aligned YBa₂Cu₃O_x crystals are discussed.     

Void fraction and pressure drop in two-phase liquid metal flows in channels

Experimental results on void fraction and friction pressure drop in vapour-potassium flows in the high-vapour-quality region up to unity are presentéd. The experimental data obtained and the pertinent results of other authors are generalized, and empirical relationship are suggested to calculate void fraction and pressure drop in two-phase liquid metal flows for channels of various configurations and orientations. The relationships are valid within the range of vapour qualities from almost zero to unit. The experimental data prove the mass velocity to have no influence on the hydrodynamic characteristics within the range of the parameters investigated. It is found in the experiments with heat supply that friction pressure losses are smaller than those for adiabatic conditions. It is shown that this result is in good correspondence with the model of the effect of injection in a boundary layer on the value of shear stresses between cases.     

Analysis of matrix damage evolution in laminated composite plates

A new model has been developed to investigate matrix cracking in laminated fibrous composite structures. The model can predict matrix cracking and its effect on stiffness reduction. It can also compute the load transfer from the cracked matrix to surrounding fibers. The model is based on the micromechanical concept of the fiber and matrix as well as the matrix material degradation concept as matrix cracking progressed. The micromechanical concept uses a rectangular cell geometry representing a fiber and its surrounding matrix while the material degradation concept uses an empirical expression of a Weibull type function. Two material constants are required for matrix cracking. The constants were obtained from an experiment on matrix cracking. With those constants, the present model predicts the matrix cracking in other cases. The predicted solutions were comparable to the experimental data.     

用于钻水平井的低密度水包油乳化钻井液

针对任平1井水平钻井的特点,研制了一种低密度、高油水比的水包油乳化钻井液。考察了乳化剂、增粘剂和配制工艺对乳状液性能的影响,评定了钻井液性能,介绍了现场应用情况。该钻井液性能稳定,润滑性好,净化井眼的能力强,能满足水平段钻井的要求。