二元Schur凹copula的次对角部分

任意给定一个二元Schur 凹copula, 结合其自身和次对角部分, 利用取大和取小运算, 构造了一类新copula, 使得次对角部分相互重合, 讨论了新copula 的Schur 凹性与Schur 几何凹性.     

NnHn(n=3～7)氮氢化合物的结构质理论研究

本文对53种NnHn(n=3～7)氮氢化合物进行了理论计算,应用自然键轨道理论(Nature Bond Orbital,NBO)和分子中的原子理论(Atoms In Molecules,AIM)分析了化合物的成键特征、相对稳定性.氮原子孤对电子与氮氮键以及氮氮键相互之间的超共轭作用是影响氮氮键长的重要因素.采用原子基团...     

双金属掺杂M2@Si20(M=Ti, Zr, Hf)团簇结构和性质的理论研究

采用密度泛函理论(DFT)和相对论有效原子核势近似(RECP),对M2@Si20(M=Ti,Zr,Hf)团簇的几何结构和电子结构性质进行研究,发现内嵌的金属二聚体和十二面体硅笼构成了稳定的富勒烯结构。通过对团簇电子结构的分析,结果表明Si20团簇掺杂双金属后稳定性得到了提高。对团簇的电荷布局分析表明过渡金属原子(Ti, Zr, Hf)和硅笼之间发生了电荷反转。     

几何量子计算和拓扑量子计算——整体性量子现象的新应用

本文概述介绍量子计算的最新进展:几何量子计算和拓扑量子计算,是初步入门的引论性质。作者从量子力学的整体性现象这一观点出发,阐述作为整体现象的量子力学几何相位(亚贝尔和非亚贝尔几何相位),量子体系的拓扑不变性质等的新应用,为先前一本著作[1]所阐述观点的新发展的补充。     

水下物体视觉形象的分析与模拟研究

水下物体的视觉形象是一个看似简单但极易出错的问题.本文对此问题进行了较为系统的分析和模拟计算,纠正了一些流行的错误看法,指出在不同情况下水下物体的表观位置、表观大小及表观形状均会发生通常直观想象难以预见的复杂变化.该问题的讨论提供了一个培养学习者创新思维和利用基本知识分析及解决实际问题的能力的极好例证.     

液体轴棱锥产生尺寸可调的单个局域空心光束

提出产生尺寸可调单个局域空心光束(bottle beam)的一种液体轴棱锥新模型.从几何光学角度分析了液体轴棱锥产生局域空心光束的原理,同时利用衍射理论加以模拟验证.得出:注入液体折射率大于轴棱锥材料折射率时可产生单个局域空心光束.通过光学设计软件TraeePro建立液体轴棱锥模型并模拟其光束传输变换特性.计算和模拟不...     

A multi-period stochastic portfolio optimization model applied for an airline company in the EU ETS

This paper aims to set up and solve a multi-period stochastic portfolio optimization model from an airline company’s point of view, considering all the specific European Union Emissions Trading Scheme (EU ETS) regulatory, managerial and trading constraints (i.e. physical constraints). Our contribution to existing academic literature is multiple. As the first ever case, we apply this technique to the aviation sector, a newly included sector within the EU ETS. More than mainly incorporating physical and technical (‘engineering’) features and focusing on short-term planning issues, we particularly address financial features and focus on mid-term planning issues. Therefore, instead of using spot prices, we run Monte Carlo simulations of correlated geometric Brownian motions (GBM) for traded futures prices of various emission allowance types for different CO₂ delivery time periods. We thereby specifically refer to the existing exchange-traded emission allowance types EU Emission Allowance (EUA) and Certified Emission Reduction (CER). By implementing actually valid and real-world-oriented regulatory constraints for EU ETS, namely managerial and trading constraints, our model implies a real-life application. We also highlight the possibility of banking and borrowing of emission allowances between CO₂ compliance periods, which is a crucial regulatory feature of EU ETS.     

球面空间中的Pedoe不等式与张-杨不等式及应用

本文应用距离几何的理论与方法,研究了n维球面空间中n维单形与有限点集的几何不等式问题,建立了球面空间中n维单形一种形式的Pedoe不等式与有限点集一种形式的张-杨不等式,并应用它获得n维球面空间中Veljan-Korchmaros型不等式与Finsler-Hadwinger型不等式.     

Maintaining the Regular Ultra Passum Law in data envelopment analysis

The variable returns to scale data envelopment analysis (DEA) model is developed with a maintained hypothesis of convexity in input–output space. This hypothesis is not consistent with standard microeconomic production theory that posits an S-shape for the production frontier, i.e. for production technologies that obey the Regular Ultra Passum Law. Consequently, measures of technical efficiency assuming convexity are biased downward. In this paper, we provide a more general DEA model that allows the S-shape.     

Riemann problem for a geometrical optics system

The paper solves analytically the Riemann problem for a nonstrictly hyperbolic system of conservation laws arising in geometrical optics,in which the flux contains the nonconvex function possessing an infinite number of inflection points.Firstly,the generalized Rankine–Hugoniot relations and entropy condition of delta shock waves and left(right)-contact delta shock waves are proposed and clarified.Secondly,with the help of the convex hull,seven kinds of structures of Riemann solutions are obtained.The solutions fall into three broad categories with a series of geometric structures involving simultaneously contact discontinuities,vacuums and delta shock waves.Finally,numerical experiments confirm the theoretical analysis.