基于门限面板模型的我国能源利用效率研究

根据三要素的柯布-道格拉斯生产函数,构建我国能源利用效率的门限面板模型,对2000~2014年我国30个省份(不含西藏)的样本数据,进行实证分析.研究表明:能源利用效率变量存在明显的三门限值,把我国30个省份分成四大类,不同类别的地区在能源效率和能源投入规模上存在显著差异.能源利用效率比较高的地区能源利用效率随能源投入增加而变大,而能源利用效率较低地区则相反.另外能源利用效率高的地区,能源投入规模大,能源产出弹性也大,说明在一定程度上对经济的贡献率也比较大,且未来继续靠能源拉动经济的可能性也比较大.     

On the relative impact of subgrid‐scale modelling and conjugate heat transfer in LES of hot jets in cross‐flow over cold plates

This work describes numerical simulations of a hot jet in cross‐flow with applications to anti‐ice systems of aircraft engine nacelles. Numerical results are compared with experimental measurements obtained at ONERA to evaluate the performances of LES in this industrial context. The combination of complex geometries requiring unstructured meshes and high Reynolds number does not allow the resolution of boundary layers so that wall models must be employed. In this framework, the relative influence of subgrid‐scale modelling and conjugate heat transfer in LESs of aerothermal flows is evaluated. After a general overview of the transverse jet simulation results, a LES coupled with a heat transfer solver in the walls is used to show that thermal boundary conditions at the wall have more influence on the results than subgrid scale models. Coupling fluid flow and heat transfer in solids simulations is the only method to specify their respective thermal boundary conditions. Copyright © 2011 John Wiley & Sons, Ltd.     

The catalyzed hydrosilation reaction: substituent effects

Ab initio electronic structure calculations using MP2 wavefunctions have been used to investigate a reaction path for the hydrosilation reaction catalyzed by divalent titanium [modeled by TiH₂, TiCl₂, and Ti(C₅H₅)₂]. Optimized structures and energies are presented. All model reactions predict a barrierless reaction path compared to a barrier of 78 kcal/mol for the uncatalyzed reaction. Received: 11 August 1998 / Accepted: 3 September 1998 / Published online: 23 February 1999     

直线加速器中的非线性空间电荷效应和发射度增长

直线加速器中束团的非线性空间电荷效应是引起发射度增长的重要原因之一．根据计算在屏蔽筒中非均匀分布京团的空间电荷效应的普遍方法，推导了直线加速器圆波导中几种非均匀分布束团的非线性场能公式，并给出数值计算结果．讨论了由非线性所引起发射度增长．     

Kinetic Carbon Isotope Effects in the Decarbonylation of Lactic Acid of Natural Isotopic Composition and of [1-14C] Lactic Acid

Studies of carbon-13 and carbon-14 kinetic isotope effects (K. I. E.) in the decarbonylation of lactic acid (L. A.) in sulphuric acid and in phosphoric acids media have been summarized and compared with earlier studies of ¹⁴C and ¹³C K. I. E. in the decarbonylation of formic and oxalic acids in concentrated sulphuric acid. Supplementary data concerning the decarbonylation of L. A. in sulphuric acid diluted with water and in pyrophosphoric acid are presented and discussed. The observed temperature dependences of ¹³C and ¹⁴C K. I. E. in concentrated H₂SO₄ and in concentrated phosphoric acids media have been rationalized by invoking a change of the mechanism of decarbonylation of L. A. in concentrated sulphuric and phosphoric acids with temperature. Preliminary calculational results concerning ¹³C and ^1??C K. I. E. in decarbonylation processes are also presented. In H₂SO₄ diluted with water and in H₃PO₄ diluted with water the temperature dependence of ¹³C and ¹⁴C K. I. E. is normal and well reproduced by one frequency approximation. In concentrated sulphuric acid and in concentrated phosphoric acids besides the C—OH bond rupture the rupture of a C—C bond had to be considered also to reproduce the observed ¹³C K. I. E. in selected temperature regions.     

1H NMR spectra of alkane‐1,3‐diols in benzene: GIAO/DFT shift calculations

The proton nuclear magnetic resonance (NMR) spectra of propane‐1,3‐diol, 2‐methylpropane‐1,3‐diol, 2,2‐dimethylpropane‐1,3‐diol, butane‐1,3‐diol, 3‐methylbutane‐1,3‐diol, pentane‐2,4‐diols (dl and meso), 2‐methylpentane‐2,4‐diol and cyclohexane‐1,3‐diols (cis and trans) in benzene have been analysed. The conformer distribution and the NMR shifts of these diols have been computed on the basis of density functional theory, the solvent being included by means of the integral equation formalism phase continuum model (IEFPCM) implemented in Gaussian 09. Relative Gibbs energies of all conformers are calculated at the Perdew, Burke and Ernzerhof (PBE)0/6‐311 + G(d,p) level, and NMR shifts by the gauge‐including atomic orbital method with the PBE0/6‐311 + G(d,p) geometry and the cc‐pVTZ basis set. Vicinal coupling constants for 1,2‐ and 1,3‐diols are rationalised in terms of relative conformer populations and geometries. The NMR shifts of hydrogen‐bonded protons in individual conformers of alkane‐1,n‐diols show a very rough correlation with the OH?OH distances. The computed overall NMR shifts for CH protons in 1,2‐ and 1,3‐diols are systematically high but correlate very well with the experimental values, with a gradient of 1.07 ± 0.01. Some values for nonequivalent methylene protons in 1,3‐diols are reversed, calculation giving enhanced values for the proton anti to the C? OH bonds. Errors in the NMR shifts computed for the OH protons of nonsymmetrical diols appear to be related to relative populations of conformers where one or other of the OH groups is the donor. Some results based on the second‐order Møller–Plesset approach, the Becke three‐parameter Lee‐Yang‐Parr method and on the IEFPCM solvation model implemented in Gaussian 03 are included. Copyright © 2013 John Wiley & Sons, Ltd.     

Random effects Weibull regression model for occupational lifetime

With great interest we read the recent publication of Sohn et al. [Sohn, S.Y., Chang, I.S., Moon, T.H., 2007. Random effects Weibull regression model for occupational lifetime. European Journal of Operational Research 179, 124–131] on a Weibull regression model with random effects for modelling occupational lifetime. We congratulate Sohn and colleagues on their comprehensive and clearly written paper. Nevertheless, we would like to comment on two points, the first regarding the moments of the underlying Weibull distribution, the second regarding the relations of Sohn’s model to the class of frailty models.     

TeV能区物理的进展

综述近年各种TeV能量对撞机的计划和建造情况,TeV能区物理的理论研究进展和TeV能区物理的发展前景.     

基于可计算一般均衡模型的出口退税政策效应分析

使用Chinagem模型计算了我国2010年6月份出口退税率下调对我国经济以及各行业的影响.研究表明,此次调整导致我国GDP实际减小0.016%,投资、出口与进口分别下降0.075%、0.041%与0.116%,居民消费和政府消费上升0.005%,就业下降0.016%,两高一资行业受挫较大.同时,各个行业实施出口退税时,对该行业的影响表现为:将直接导致行业出口价格上升,出口量下降,从而国内销售部分增加;由于国内供给增加,进口有所减少;而总产出的变化则由于行业不同而呈现出不同的变化.与此同时,各个行业出口退税率的变化将导致上游行业产出下降,下游行业产出增长.