Tri-Gate Bulk MOSFET Design for CMOS Scaling to the End of the Roadmap

A tri-gate bulk MOSFET design utilizing a low-aspect-ratio channel is proposed to provide an evolutionary pathway for CMOS scaling to the end of the roadmap. 3-D device simulations indicate that this design offers the advantages of a multi-gate FET (reduced variability in performance and improved scalability) together with the advantages of a conventional planar MOSFET (low substrate cost and capability for dynamic threshold-voltage control).     

Preparation of gelatinous aluminium hydroxide by urea from aqueous solutions containing chloride,nitrate and sulphate of aluminium

The preparation of gelatinous aluminium hydroxide from aqueous solutions containing a mixture of the chloride, nitrate or sulphate of aluminium and urea by heating at 95°C has been investigated under different conditions. The pH value of aqueous solutions, on heating for a given period of time, gradually increases, rises steeply at pH 4.0–7.5 and finally approaches a constant value. The precipitate appears at about pH 7 in the presence of chloride or nitrate ions and about pH 4 in the presence of sulphate ions. Although the gelatinous precipitates in the chloride and nitrate systems are apparently different from the granular, filterable one in the sulphate system, their compositions are not influenced by the species of aluminium salt. The fresh precipitates exist in an amorphous state, and go to pseudoboehmite by ageing. It seems that the amount of pseudoboehmite increases as the concentration of aluminium salt in aqueous solution decreases. However, the transformation from amorphous aluminium hydroxide to pseudoboehmite is reduced in the presence of sulphate ions. Furthermore, it is found that the X-ray diffraction peak for the (200) plane, as an orthorhombic structure, in the pseudoboehmite precipitated from chloride or nitrate solution is more intense than that from sulphate solution.     

Simulation of postoperative 3D facial morphology using a physics-based head model

We propose a prototype of a facial surgery simulation system for surgical planning and the prediction of facial deformation. We use a physics-based human head model. Our head model has a 3D hierarchical structure that consists of soft tissue and the skull, constructed from the exact 3D CT patient data. Anatomic points measured on X-ray images from both frontal and side views are used to fire the model to the patient's head. The purposes of this research is to analyze the relationship between changes of mandibular position and facial morphology after orthognathic surgery, and to simulate the exact postoperative 3D facial shape. In the experiment, we used our model to predict the facial shape after surgery for patients with mandibular prognathism. Comparing the simulation results and the actual facial images after the surgery shows that the proposed method is practical.     

我国卫星测控系统发展概况及几点建议

本文介绍了我国国内C频段、国际C频段两个卫星测控网站,三代典型微波统一测控系统的特点,提出了对新型航天测控设备研制的建议。     

Geometrical Characteristics and Surface Polarity of Inclined Crystallographic Planes of the Wurtzite and Zincblende Structures

Inclined crystallographic planes of the wurtzite structure were investigated in comparison with the zincblende structure in terms of surface geometry characteristics. The ball–stick model indicates that the semipolar surface possesses a surface polarity resembling the anion polarity, which agrees with the common experimental observations of epitaxial growth preference for the cation-polarity surface over the surface. The wurtzite surface was found to share geometrical similarities with the zincblende {100} surface uniquely among the possible semipolar planes. This finding encourages epitaxial growth on the plane of wurtzite semiconductors, e.g., GaN, with the potential of avoiding atomic step formations typically associated with off-axis crystallographic planes.     

Analog Circuit Design Methodology in a Low Power RISC Microprocessor

There are various kinds of analog CMOS circuits in microprocessors. IOs, clock distribution circuits including PLL, memories are the main analog circuits. The circuit techniques to achieve low power dissipation combined with high performance in newest prototype chip in the Super H RISC engines are described. A TLB delay can be decreased by using a CAM with a differential amplifier to generate the match signal. The accelerator circuit also helps to speed up the TLB circuit, enabling single-cycle operation. A fabricated 96-mm² test chip with the super H architecture using 0.35-m four metal CMOS technology is capable of 167-MHz operation at 300 Dhrystone MIPS with 2.0-W power dissipation.     

ITU-R P.434计算F2层基本最高可用频率与实测值的比较

利用我国2011年1月和7月10条斜测电路的F₂层基本最高可用频率(MUF)月中值数据,与ITU-R P.434方法计算的F₂层基本MUF进行了比较,分析了该方法在中国地区的适用性。结果表明:ITU-R P.434方法在中国地区具有较好的适用性,但在某些电路的个别时段偏差较大。其中,1月份在中纬地区日出时段,该方法给出的基本MUF与月中值相比偏低20%~30%,在日落时段则偏高20%~30%;低纬地区夜间时段两者的相对偏差较大,最大值达到40%.7月份,该方法的结果与各条电路的实测结果基本一致,相对偏差在-10%~20%之间。上述结果对短波通信的选频等具有一定的指导意义。     

A life-cycle analysis on thin-film CdS/CdTe PV modules

Authors have evaluated the life cycle of a thin-film CdS/CdTe PV module to estimate the energy payback time (EPT) and the life-cycle CO₂ emissions of a residential rooftop PV system using the CdS/CdTe PV modules. The primary energy requirement for producing 1 m² of the CdS/CdTe PV module was similar to a-Si PV module at annual production scale of 100 MW. EPT was calculated at 1.7–1.1 yr, which was much shorter than the lifetime of the PV system and similar to that of a-Si PV modules. The life-cycle CO₂ emissions were also estimated at 14–9 g-C/kWh, which was less than that of electricity generated by utility companies.     

用倒锥形测头测量蜗杆及滚刀齿形的测头半径补偿

根据倒锥形测头中心的轨迹曲线,分析了测量接触点与测头中心的相对位置关系。提出消除由于测头半径所引起的测量误差的原理,并给出了圆弧齿轮滚刀的齿形测量实例。