CFETR产氚包层与偏滤器部件在热室内维修与退役流程的概念设计

为保证聚变堆环境的核安全,需要在热室内及时对产氚包层及偏滤器进行检测、维修或退役处理。 针对 CFETR 产氚包层与偏滤器结构特点,设计了一套在热室内维修与退役处理的工作流程,包括放射性废物处 理、核去污、除氚等关键工艺,并参照 ITER 设计,遵循 ALARA 原则,完成了热室内各功能区域的放射性分级。     

使用DNA分子实现逻辑门操控

DNA分子编码地球上所有形式的生命,可以论证:就数据存储和处理而言,它们是已知的最强有力的媒介.然而,迄今DNA几乎没有被用于计算机,其原因主要是:缺乏一种方法,能够将生命分子转换成器件,而后者可以完成逻辑操作.最近,来自韩国先进科技研究院的Park等在应用化学国际杂志(Angew.Chem.Int.Edn49,9757-9760(2010))上撰文,报告了他们在DNA分子逻辑门操控方面的进展.     

Simulation of SET Operation in Phase-Change Random Access Memories with Heater Addition and Ring-Type Contactor for Low-Power Consumption by Finite Element Modeling

A three-dimensional finite element model for phase change random access memory （PCRAM） is established for comprehensive electrical and thermal analysis during SET operation. The SET behaviours of the heater addition structure （HS） and the ring-type contact in bottom electrode （RIB） structure are compared with each other. There are two ways to reduce the RESET current, applying a high resistivity interracial layer and building a new device structure. The simulation resuIts indicate that the variation of SET current with different power reduction ways is little. This study takes the RESET and SET operation current into consideration, showing that the RIB structure PCRAM cell is suitable for future devices with high heat efficiency and high-density, due to its high heat efficiency in RESET operation.     

Weighted Composition Operators from the Bloch Space to Weighted Banach Spaces on Bounded Homogeneous Domains

We study the bounded and the compact weighted composition operators from the Bloch space into the weighted Banach spaces of holomorphic functions on bounded homogeneous domains, with particular attention to the unit polydisk. For bounded homogeneous domains, we characterize the bounded weighted composition operators and determine the operator norm. In addition, we provide sufficient conditions for compactness. For the unit polydisk, we completely characterize the compact weighted composition operators, as well as provide ＂computable＂ estimates on the operator norm.     

预判宏观“钱途”

岁末将至,又到年终盘点与展望时。2009年,中国经济在＂保增长、扩内需、调结构＂思想指导下,通过一揽子刺激措施保持了较快增速。然而,随着经济形势好转,＂非常政策＂的走向正成为市场关注焦点。即将召开的2009年中央经济工作会议,将会就市场关注的政策问题给出明确答案。同时,作为年度宏观经济政策最权威的风向标,中央经济工作会议的决议将成为企业资本市场操作守则。     

High-efficiency S-band harmonic tuning GaN amplifier

In this paper, we present a high-efficiency S-band gallium nitride （GaN） power amplifier （PA）. This amplifier is fabri- cated based on a self-developed GaN high-electron-mobility transistor （HEMT） with 10 mm gate width on SiC substrate. Harmonic manipulation circuits are presented in the amplifier. The matching networks consist of microstrip lines and discrete components. Open-circuited stub lines in both input and output are used to tune the 2rid harmonic wave and match the GaN HEMT to the highest efficiency condition. The developed amplifier delivers an output power of 48.5 dBm （70 W） with a power-added efficiency （PAE） of 72.2% at 2 GHz in pulse condition. When operating at 1.8-2.2 GHz （20% relative bandwidth）, the amplifier provides an output power higher than 48 dBm （,-~ 65 W）, with a PAE over 70% and a power gain above 15 dB. When operating in continuous-wave （CW） operating conditions, the amplifier gives an output power over 46 dBm （40 W） with PAE beyond 60% over the whole operation frequency range.     

Metamaterial inspired terahertz devices: from ultra-sensitive sensing to near field manipulation

We present a review of terahertz plasmonic metamaterial devices that have functionalities and applications ranging from sensing, enhanced electromagnetic fields, and near field manipulation. Metamaterials allow the properties of light propagation to be manipulated at will by using a combination of appropriately designed geometry and suitable materials at the unit cell level. In this review, we first discuss the sensing aspect of a planar plasmonic metamaterial and how to overcome its limitations. Conventional symmetric metamaterials are limited by their low Q factor, thus we probed the symmetry broken plasmonic metamaterial structures in which the interference between a broad continuum mode and a narrow localized mode leads to the excitation of the sharp Fano resonances. We also discuss the near field mediated excitation of dark plasmonic modes in metamaterials that is caused by a strong coupling from the bright mode resonator. The near field coupling between the dark and bright mode resonances leads to classical analogue of electromagnetically induced transparency in plasmonic systems. Finally, we discuss active switching in terahertz metamaterials based on high temperature superconductors that holds the promise of reducing the resistive losses in these systems, though it fails to suppress the radiation loss in plasmonic metamaterial at terahertz frequencies.     

Performance of an optically addressed liquid crystal light valve and its application in optics damage protection

We report an optically addressed liquid crystal light valve, a home-made device that has solved the problem of low transmittance caused by opaque electrodes in present transmissive spatial light modulators. The operating characteristic of the light valve is analyzed. The optimum driving voltage of this device is 27 V at 300 Hz, as deduced from the equivalent electric model. Its transmittance reaches 80% and its contrast is approximately 40:1. Its dynamic performance, especially its ability to obscure laser light at programmed locations, is demonstrated. The results are in good agreement with the desired shape, which indicates that our light valve performs very well.