Plasma immersion ion implantation for SOI synthesis: SIMOX and ion-cut

We have demonstrated feasibility to form silicon-on-insulator (SOI) substrates using plasma immersion ion implantation (PIII) for both separation by implantation of oxygen and ion-cut. This high throughput technique can substantially lower the high cost of SOI substrates due to the simpler implanter design as well as ease of maintenance. For separation by plasma implantation of oxygen wafers, secondary ion mass spectrometry analysis and cross-sectional transmission electron micrographs show continuous buried oxide formation under a single-crystal silicon overlayer with sharp Si/SiO₂ interfaces after oxygen plasma implantation and high-temperature (1300°C) annealing. Ion-cut SOI wafer fabrication technique is implemented for the first time using PIII. The hydrogen plasma can be optimized so that only one ion species is dominant in concentration and there are minimal effects by other residual ions on the ion-cut process. The physical mechanism of hydrogen induced silicon surface layer cleavage has been investigated. An ideal gas law model of the microcavity internal pressure combined with a two-dimensional finite element fracture mechanics model is used to approximate the fracture driving force which is sufficient to overcome the silicon fracture resistance.     

Superconducting control for surge currents

Systems designed to use superconductors to limit fault currents in power grids are undergoing testing. The authors describe superconducting fault current limiters (SCFCL) which may be categorised into resistive or shielded core types. The features and operation of each type of device are outlined. Both the shielded-core and resistive types of SCFCL use the same amount of superconductor material to achieve a given limitation behavior. This is because the rated power per volume of conductor is determined by the product of fault-induced field and critical current, which is the same for both devices, assuming the same type of superconducting material is employed. The shielded-core limiter works only with AC currents and is much larger and heavier than the resistive SCFCL. While there is only one large program left in the low-temperature type of SCFCL, more than 10 major projects are under way worldwide on the high-temperature type of device. The main reason is the lower HTS cooling cost     

Accuracy and stability improvements of integral equation modelsusing the partial element equivalent circuit (PEEC) approach

The partial element equivalent circuit (PEEC) technique is a formulation which transforms an electric field integral equation (EFIE) into a full-wave equivalent circuit solution. In this paper, improvements are made to the PEEC model through the development of a refined method of computing both the partial inductances as well as the coefficients of potential. The method does not increase the number of unknowns. In addition, damping is added to the PEEC model in order to further reduce nonphysical resonances which may occur above the useful frequency range, The observations and solutions presented in this paper are especially important for time domain solvers. The effectiveness of the method is illustrated with several examples     

直径2mm电磁型微马达的研制及其气隙磁场的分析

微机电系统（ＭＥＭＳ）是正在国际上发展的新兴学科,微马达是微机电系统中的关键器件,本文介绍了研制成的直径为２ｍｍ、高０．７ｍｍ的电磁型微马达的结构特点,并对气隙磁场分布进行了分析讨论。     

AUTO-SMASH: A self-calibrating technique for SMASH imaging

Recently a new fast magnetic resonance imaging strategy, SMASH, has been described, which is based on partially parallel imaging with radiofrequency coil arrays. In this paper, an internal sensitivity calibration technique for the SMASH imaging method using self-calibration signals is described. Coil sensitivity information required for SMASH imaging is obtained during the actual scan using correlations between undersampled SMASH signal data and additionally sampled calibration signals with appropriate offsets ink-space. The advantages of this sensitivity reference method are that no extra coil array sensitivity maps have to be acquired and that it provides coil sensitivity information in areas of highly non-uniform spin-density. This auto-calibrating approach can be easily implemented with only a small sacrifice of the overall time savings afforded by SMASH imaging. The results obtained from phantom imaging experiments and from cardiac studies in nine volunteers indicate that the self-calibrating approach is an effective method to increase the potential and the flexibility of rapid imaging with SMASH.     

AutoCAD的菜单定制技术

AutoCAD R14及其以上版本提供了灵活的菜单定制技术,用户可用命令或宏的形式按自己的喜好对菜单进行随意定制.本文对AutoCAD的菜单文件结构、菜单文件的组成、用户文件的编制过程、工具条按钮等菜单定制技术作了探讨,并给出了部分实例代码.     

化肥工业气化型煤工业性试验研究

针对气化型煤固定炭含量低、热稳定性差等难题 ,研制了新的成型工艺和添加剂。造气工业性试验结果表明 ,该技术节能降耗 ,降低环境污染 ,具有良好的经济效益和环境效益     

地矿企业技术创新分析

本讲座了地矿企业技术创新的重要性,分析了过去创新实践中的不足之处,指出了地矿企业当前可行的技术创新模式,并就政府如何支持地矿企业技术创新给出了一些建议。     

高峰矿区地压显现规律研究

高峰矿区因开采条件复杂且民采破坏严重,造成上覆围岩多次跨塌,存在突发性的冲击地压危险,属于重大事故隐患区。针对这一问题,必须立项对地压进行监测,且实践证明是可行的。根据是的监测数据,得出了高峰矿区地压显现规律。     

Alpha-stable分布粗糙土壤表面电磁散射研究

采用空间域合成法生成高度起伏遵守Alpha-stable分布的粗糙土壤表面,运用矩量法研究了锥形入射波入射时粗糙土壤表面的电磁散射特性.数值计算了散射系数随散射角的变化关系,分析了稳定性系数、归一化尺度参数、互相关长度、入射波频率、土壤湿度对散射系数的影响.结果表明,稳定性系数、归一化尺度参数、互相关长度、入射波频率、土壤湿度对散射系数均有较大的影响,遵守不同的规律.