葡萄糖还原法制备CuCl/NaY吸附剂及其CO吸附和CO/H2分离性能

以NaY分子筛为载体,CuCl2为铜源,加入还原剂葡萄糖,在温和条件下制备CuCl/NaY吸附剂,通过变压吸附考察了该吸附剂对CO的吸附性能及CO/H2的分离性能。运用X射线衍射（XRD）、X射线光电子能谱（XPS）及程序升温还原（TPR）对吸附剂进行表征,结果表明采用葡萄糖还原法制备CuCl/NaY吸附剂,其制备条件温和,吸附剂表面的亚铜含量高,对CO的吸附及CO/H2的分离性能优越且稳定性好。     

Two-dimensional threshold voltage model of nanoscale silicon-on-insulator tunneling field-effect transistor

The tunneling field-effect transistor (TFET) is a potential candidate for the post-CMOS era. In this paper, a threshold voltage model is developed for this new kind of device. First, two-dimensional (2D) models are used to describe the distributions of potential and electric field in the channel and two depletion regions. Then based on the physical definition of threshold voltage for the nanoscale TFET, the threshold voltage model is developed. The accuracy of the proposed model is verified by comparing the calculated results with the 2D device simulation data. It has been demonstrated that the effects of varying the device parameters can easily be investigated using the model presented in this paper. This threshold voltage model provides a valuable reference to the TFET device design, simulation, and fabrication.     

Tunneling field effect transistors based on in-plane and vertical layered phosphorus heterostructures

Tunneling field effect transistors(TFETs) based on two-dimensional materials are promising contenders to the traditional metal oxide semiconductor field effect transistor, mainly due to potential applications in low power devices. Here,we investigate the TFETs based on two different integration types: in-plane and vertical heterostructures composed of two kinds of layered phosphorous(β-P and δ-P) by ab initio quantum transport simulations. NDR effects have been observed in both in-plane and vertical heterostructures, and the effects become significant with the highest peak-to-valley ratio(PVR)when the intrinsic region length is near zero. Compared with the in-plane TFET based on β-P and δ-P, better performance with a higher on/off current ratio of ～ 10~6 and a steeper subthreshold swing(SS) of ～ 23 m V/dec is achieved in the vertical TFET. Such differences in the NDR effects, on/off current ratio and SS are attributed to the distinct interaction nature of theβ-P and δ-P layers in the in-plane and vertical heterostructures.     

基于SPH法的二维矩形液舱晃荡研究

液体晃荡是一种复杂的流体运动现象,自由液面的存在使得该现象具有很强的非线性和随机性。针对二维矩形液舱在不同振幅水平激励下的纵荡问题,应用SPH法对其进行了数值研究。首先计算了小振幅激励下的纵荡,计算结果分别与线性理论解、文献VOF法结果及文献SPH法结果作了比较分析,以验证所建数值模型的合理性;然后计算了液舱在大振幅水平激励下的纵荡,着重分析了不同振幅下液体晃荡的速度向量图、液面波动时程、压强波动时程、动量波动时程以及波动的频谱图,并将计算所得液面波动结果与小振幅激励下的液面波动结果作了比较。分析结果表明,在大振幅水平激励下,液面波动的波峰值较小振幅下的结果有较为明显的增大,而波谷值则无过大的变化,总体波动幅值比小振幅下的结果大;随着激励幅值的增大,液面波动幅值呈现明显增大的趋势,压强的整体波动幅值也呈增大趋势,动量波动的均值亦有明显增大;波动能量随着激励幅值的增大而增大并向第一阶频率区域集中。SPH法对处理液体大幅晃荡这种具有自由表面大变形的问题有十分优越的特性。     

Economical phase-covariant cloning with multiclones

This paper presents a very simple method to derive the explicit transformations of the optimal economical 1 to M phase-covariant cloning. The fidelity of clones reaches the theoretic bound [D'Ariano G M and Macchiavello C 2003 Phys. Rev. A 67 042306]. The derived transformations cover the previous contributions [Delgado Y, Lamata L et al, 2007 Phys. Rev. Lett.98 150502] in which M must be odd.     

变压吸附技术的研究

介绍了变压吸附技术应用于空气干燥和氧气富集的实验．分别对两种分子筛的吸附性能进行了讨论。     

信息不对称，会计准则规范的经济理由

会计准则规范作为一种经济性规制,而产生的经济机理有多种不同的理解和解释,本从会计准则在于生成会计信息的决策有用性这一要旨为出发点,认为：会计准则规范的基本经济理由和根本作用在于消除或减少信息不对称,通过会计准则对会计信息生成过程及结果的规范,使会计信息的披露达到均衡,客观与公正,从而发挥会计信息在市场决策中的积极经济影响。     

Oxygen Selectivity on Partially K Exchanged Na-A Type Zeolite at Low Temperature

In previous work by the authors on Na-A zeolite (Izumi et al., Japan Patent Toku-Kou-Shou 63-058614, 1988), it was shown that the combination of high-temperature calcination and operation of the adsorption step at low temperatures improved the selectivity for oxygen over nitrogen from air (Izumi et al., CATS J Meeting Abstracts, 31(2A), 10, 1989; Izumi and Suzuki, Adsorption, 6, 2000). Berlin discloses in his U.S. Patent 3282028 (1966) that the partial exchange of potassium ions for sodium ions in the Na-A type zeolite also improved selectivity for oxygen by reducing the uptake rate of nitrogen. It was therefore expected that the oxygen selectivity of Na-K-A with high-temperature calcination and low-temperature adsorption might be enhanced. For the confirmation of optimum conditions for the appearance of oxygen selectivity on Na-K-A, samples were prepared with a K exchange ratio varied from 0–20 mol% (0–2.4 K ions/unit cell), and a calcination temperature varied from 923 to 1073 K, and an experiment concerning oxygen and nitrogen adsorption on Na-K-A was undertaken with a small adsorbent column under pressure swing adsorption (PSA) conditions at adsorption temperatures from room temperature to 213 K. It was found that (a) the K exchange ratio of 7 mol% (0.84 K ions/unit cell), and (b) the calcination temperature of 993 K, resulted in a remarkable increase in oxygen selectivity. Under optimum conditions for Na-K-A, the oxygen separation factor was about 8. Na-K-A has the potential to effectively separate oxygen and nitrogen from air by means of PSA.     

我国城乡空间生态规划新思路

以我国现阶段城乡发展的突出特点为背景,分析了传统的区域、城市规划重经济轻生态、重城市轻乡村的情况,以及“自然优先”的“反规划”方法在现阶段实施的客观困难．针对这种情况,从“中立”的视角,提出了城市规划和城乡空间生态规划相融合的理念和方法,并指出其具体的融合点为空间管治规划．     

大尺寸金红石(TiO2)单晶体生长条件的实验研究

采用高纯(99.995;)、超细的金红石(TiO2)粉末为起始原料,用燃熔法制备了尺寸为30mm×50mm的金红石(TiO2)单晶体.讨论了生长气氛、生长速度、温度梯度在晶体生长中的作用,对比了晶体在空气中与在氧气中退火的结果,测定了晶体试样的摇摆曲线和透过率,并与商用晶体的透过率进行了比较.实验表明:生长气氛中的氧分压大于液固界面(即生长界面)处熔体的氧离解压是生长完整晶体的必要条件;在此条件下,能否生长为大尺寸晶体则取决于炉膛的轴向温度梯度;晶体在退火过程中可消除热应力,但退火更重要的作用是通过氧化反应消除氧空位,在氧气氛中退火,可明显缩短退火时间;所制备的晶体完整性较好,透过率与商用晶体基本一致.