3mm波段极近距离雷达

提出一种极近距离雷达概念，并导出其作用距离公式，在此基础上研制出一台３ｍｍ波段极近距离多普勒雷达样机．试验结果表明该雷达结构简单，成本低廉，在作用距离为零点几米至几米范围内可获得较高的定距精度．     

Microstructure study of Sm,Mn-modified PbTiO3 piezoelectric ceramics by XRD profile-fitting technique

By using the X-ray diffraction profile-fitting technique, the microstructures of Sm, Mn-modified PbTiO₃ piezoelectric ceramic discs, including ferroelectric domain sizes, microstrains, and their variations with the poling strength have been quantitatively investigated. The results manifest that the modified PbTiO₃ ceramics contain a high density of domain walls due to the presence of finely-divided coherent domain structures (tens of nanometres in dimension). The poling treament can evidently influence the domain-size distribution, with a more homogeneous microstructure being developed; however, it simultaneously causes high anisotropic microstrains within the structure which, together with the high density of domain walls, is expected to be responsible for the unusual high electromechanical coupling properties possessed by this material.     

高能气体压裂联作技术进展

国内高能气体压裂增产技术已经由单一的有壳弹、无壳弹、液体药、可控脉冲等高能气体压裂,进展到与射孔、水力压裂、酸化、化学解堵等技术相联作的综合压裂阶段。分别对高能气体压裂与射孔、水力压裂和化学解堵等联作技术的基本原理、现场试验、作业效果等进行了介绍。高能气体压裂已发展成一种基本成熟的、综合性油气田增产改造新技术。     

用AIR-C2H2原子吸收光谱法测定镉镍电池正极浸渍液中钴含量

本文主要简述与运用AIR-C2H2原子吸收光谱法进行镉镍电池正极浸渍液中钴含量的测定，介绍了钴最佳测定条件及呈良好线性范围的浓度。同时对样品消化处理条件，在测定中样品的干扰因素进行了综合考虑，该方法具有很好的灵敏度，很好的重复性，干扰小，同时具有方法步骤简单，操作容易掌握等特点，对样品钴含量的测定，其相对标准偏差均小于1.0%（n=6），标准加入回收率均在97.0%～102.0%(n=5）范围内，结果表明，运用AIR-C2H2原子吸收光谱法测定镉镍电池正极浸渍液中钴含量的分析，达到了实验室分析质量控制的要求，完全适用于镉镍电池正极浸渍液中钴含量的控制分析和样品系统分析。     

Development of Bi(Pb)-2223/Ag pancake-shaped and solenoidal coils

High temperature superconducting (HTSC) multifilamentary (MT) Bi(Pb)-2223/Ag tapes with reproducible critical current density of between 15000 and 20000 A/cm² at 77 K in self field have been achieved using the standard flat-rolling method as the intermediate deformation between sintering periods. Long lengths of Bi(Pb)-2223/Ag MT tapes up to 43 m prepared by the conventional method of powder-in-tube (PIT) have been successfully produced on a laboratory scale. Several coils have been fabricated from sections of the long length tape, using the co-wound wind-and-react (W&R) procedure for the pancake-shaped and the singly-wound W&R as well as R&W procedure for the solenoidal coils. A novel W&R solenoidal coil (reaching ~973 ampere-turns) wound on an alumina ceramic tube generates a DC field of ~19 mT at 77 K and has been fabricated together with five pancake-shaped coils, each generating an average of ~5 mT at 77 K. These are destined for magnet construction with a possible combined calculated field of ~0.04 T at 77 K (with liquid nitrogen as a coolant)     

浅谈实验室检验在科研生产中的作用

文章阐述了实验窀检验在科研生产中的作用及发挥作用的巨大潜力。     

HfOxNy的场发射特性

用直流溅射和高温退火相结合的方法制备了HfOxNy薄膜并测试了其场发射性能,发现其具有较低的开启电场、较大的发射电流密度以及很好的发射稳定性.高压"锻炼"对提高HfOxNy场发射性能起着关键作用,这与高压"锻炼"下薄膜内部结构和表面性质的改变有关.对场发射机理的研究表明,HfOxNy的场发射符合经典的FN隧穿理论.     

A force modulation study on crystallization process in ferroelectric vinylidene fluoride and trifluoroethylene copolymer films

This paper introduces the Force Modulation technique to the study of crystallization process in ferroelectric vinylidene fluoride and trifluoroethylene copolymer films. Using this technique we have successfully visualized ferroelectric crystalline domains and observed that these ferroelectric domains grow out from amorphous phase, unite into strip-like structures, and finally congregate into a union. Force Modulation can weaken the influence of topography on imaging of ferroelectric domains, and reveal more details, which are difficult to be observed in topographical image.     

Development of a heterogeneous microstructurally based finite element model for the prediction of forming limit diagram for sheet material

A heterogeneous finite element model with randomly distributed inhomogeneities has been developed for the determination of the forming limit diagram (FLD) for thin aluminum sheet material based on the prediction of localized necking. The strength difference between the inhomogeneities and the matrix is ascertained either from the fluctuation of the experimental stress-strain curve or from a micromechanical analysis that uses a representative particle field. By changing the specimen geometry and friction conditions, different stress states (or strain paths) are achieved. A plot of the critical Oyane fracture parameter is used to identify the limit strain state. Also, a plot of equivalent plastic strain rate is used to distinguish the boundary of intense shear bands and hence to identify where to take the measurement point. Both a plane stress model and a three-dimensional (3-D) model are adopted to predict the shear banding phenomenon and hence the FLD. The predicted FLD agrees well with the measurements from a recent round robin experimental FLD involving several independent research laboratories. The Taguchi method is applied to assess how the various parameters involved in the heterogeneous model affect the calculated forming limit strain.     

化学教学中"多媒体教学课件开发"基本思路的探讨

在电化教学的基础上，现代教育技术在教学领域里起着越来越重要的作用，而多媒体教学课件。则是现代教育技术领域内的一技奇芭，正逐渐地放射出强大的、耀眼的光辉。本文将从四个方面探讨化学教学中“多媒体教学课件开发”的基本思路。