High electrical performance liquid-phase HBr oxidation gate insulator of InAlAs/InGaAs metamorphic MOS-mHEMT

The InAlAs/InGaAs metal-oxide-semiconductor metamorphic high electron mobility transistors (MOS-mHEMTs) were demonstrated by using liquid-phase HBr treatment technology to form a high-quality gate insulator layer. In this study, liquid-phase HBr treatment technology was used instead of traditional plasma-assisted chemical vapor deposition (PECVD) because the proposed technology can prevent the device from plasma-induced damage. The novel HBr + ultraviolet (UV) illumination treated InGaAs provided a lower surface states such that MOS structure can be efficiently obtained. Besides, based on the atomic force microscopy (AFM) measurement, the native oxides film formed by HBr + UV illumination treatment also provided a better surface roughness compared to traditional NH₄OH and only HBr treatment solutions. It is beneficial for reducing the surface traps and lowering the leakage current in MOS-mHEMTs. Based on the flicker noise and load-pull power measurement results, HBr + UV treatment mHEMT achieved a low flicker noise at high current level and the power-added efficiency can be enhanced up to 9%. Therefore, the novel liquid phase method of HBr + UV illumination treatment exhibited a highly potential for low noise microwave power device applications.     

Measurement system escape and overkill rate analysis

In 100% inspection, measurement errors are unavoidable. Due to these errors, acceptable products are sometimes rejected (overkill) and defective products are accepted (escape). Overkill increases production costs, while escape is a source of customer dissatisfaction. This study presents a model for calculating overkill and escape rates using process and measurement system performance data. A practical example of applying the model is also presented to calculate gage reproducibility and repeatability requirements for different production settings. Industrial managers and quality engineers can utilize the results of this study to calculate escape and overkill rates of their production systems, and to assess and improve their processes.     

应用型本科院校非英语专业学生英语发展性学力的调查与研究

应用型本科院校担负着为地方以及周边地区培养具有生产、经营、管理、教学等知识和技能的专门性人才的艰巨任务,非英语专业大学英语课程是应用型本科院校开设的一门必修课程和公共性课程.无论在规模上还是在权重上,大学英语课程都占据极其重要的地位.从学力理论的发展性学力视角探究该课程的承载者,无论对教学对象本身、英语教师的教学以及教学管理来说都具有极其重要的参考价值.     

A statistical micromechanical model of multiple cracking for ultra high toughness cementitious composites

A new statistical micromechanical model of multiple cracking is proposed in which a general expression of the fiber bridging stress laws in the crack plane is established. In this model, the random distribution properties of fibers are considered. And the Weibull function is adopted to represent the flaw size distribution. The relationships of stress versus strain and crack width versus strain are proposed. The formulas of the crack width, crack space, strain capacity and fracture energy density at the end of multiple cracking processes are also deduced. The validity of the proposed model was demonstrated by experimental results.     

Luminescence hydrogenated nanoamorphous Si films fabricated by reactive pulsed laser ablation

Hydrogenated nanoamorphous Si (na-Si:H) films have been fabricated by reactive pulsed laser ablation technique with hydrogen as reactive gas. It is found that the hydrogen pressure has a great effect on both the structure and photoluminescence (PL) properties of the films. Increasing the hydrogen pressure leads to a structural transition of the films from amphorous Si to na-Si:H, and the PL center wavelength of the na-Si:H films is varied with the hydrogen pressure. The PL decay times of the na-Si:H films are in the nanosecond scale and are shorter on the high energy side of their PL spectrum. The results demonstrate that the na-Si:H films are promising candidates for visible, tunable and high-performance light-emitting devices.     

Relationship Between Embedding Depth and Residual Stress in the cBN Grain of Monolayer Brazed Abrasive Tools

The relationship between the embedding depth and the residual stress in the brazed cBN grains is analyzed experimentally in order to optimize the embedding depth of grains in the monolayer brazed abrasive tools. It is found that the residual stress is stable without remarkable gradient in the core zones of the brazed grains. However, the stress distribution gradient is rather great in the regions such as both ends of the central axis, the margin region of the central plane in the cBN grains, and the margin region of the section plane between the grains and the filler top. The maximum tensile stress in the margin zone of the brazed cBN grains has the most important influence on the mechanical property of the grains. The embedding depth is accordingly optimized at 30-40% of the total height of cBN grain.     

加强行业标准化工作 促进煤炭工业科学发展

总结了近5年来煤炭行业标准制定修订情况,分析了煤炭行业标准在煤炭工业快速稳定发展中的地位和作用。探讨了煤炭行业标准化工作中存在的主要问题,并有针对性地提出今后煤炭行业标准化工作重点的建议。     

窃电与反窃电技术分析

分析失压和欠压窃电、TA短接分流、电压相序颠倒等错误接线和强磁干扰的窃电方式,介绍窃电情况的检查判断与电量的追补计算方法,提出使用新一代多功能电能表、推广反窃电监测报警系统等防范窃电的措施.     

Coordination of Midterm Outage Scheduling With Short-Term Security-Constrained Unit Commitment

The proposed model solves the coordinated generation and transmission maintenance scheduling with security-constrained unit commitment (SCUC) over the scheduling horizon of weeks to months. The model applies the Lagrangian relaxation technique to decompose the optimization problem into subproblems for generation maintenance scheduling, transmission maintenance scheduling, and short-term SCUC. The decomposition and cooperation strategy is applied to the first two subproblems for the scheduling of generation and transmission maintenance. The SCUC solution is based on the mixed integer programming (MIP) technique. The optimal hourly results for maintenance scheduling, generation unit commitment, and transmission flows are obtained using a chronological load curve. Effective strategies are applied for accelerating the convergence of the hourly solution. The numerical examples demonstrate the effectiveness of the proposed model.     

直拉单晶硅中氧沉淀的高温消融和再生长

重点研究了直拉(CZ)硅中氧沉淀在快速热处理(RTP)和常规炉退火过程中的高温消融以及再生长行为.实验发现,RTP是一种快速消融氧沉淀的有效方式,比常规炉退火消融氧沉淀更加显著.硅片经RTP消融处理后,在氧沉淀再生长退火过程中,硅中体微缺陷(BMD)的密度显著增加,BMD的平均尺寸略有增加;而经过常规炉退火消融处理后,在后续退火过程中,BMD的密度变化不大,但BMD的尺寸明显增大.氧沉淀消融处理后,后续退火的温度越高,氧沉淀的再生长越快.