Poisson-Geometric模型下时间一致的最优再保险-投资策略选择

本文研究Poisson-Geometric模型下,时间一致的再保险-投资策略选择问题.在风险模型中,理赔发生次数用Poisson-Geometric过程描述,保险公司在进行再保险时,按照方差值原理计算再保险的保费.保险人在金融市场上投资时,风险资产满足带跳的随机微分方程.保险人的目标是,选择一个时间一致的再保险-投资策略,最大化终止时刻财富的均值同时最小化其方差.通过使用随机控制理论,求得时间一致的再保险-投资策略以及值函数的显式解.最后分析结果的经济意义,并通过数值计算,解释了模型参数对最优策略的影响.     

Ce3+,Eu2+共掺Ba3Si6O12N2荧光粉发光特性及能量传递研究

通过高温固相法制备了一系列Ce3+/Eu2+共掺杂的Ba3Si6O12N2,利用X射线衍射(XRD)研究了其晶体结构.研究表明,Ba3Si6O12N2∶ Ce3+,Eu2+荧光粉在338 nm光激发下可以发射525 nm的绿光,且具有较大的半峰宽.研究还发现,单掺Ce3的发射光谱和单掺Eu2+的发射光谱存在交叠,同时Ce3+的5d1最低能级能量低于Eu2+的4f65d1最低能级,这二者共同证实了可能存在Ce3+到Eu2+的能量转移现象.同时还研究了Ce3+浓度对Ba(2.7-y)Si6O12N2∶0.3Eu2+,yCe3+(0≤y≤0.1)系列荧光粉发光强度和波长的影响.热猝灭性能研究表明,Ce3+引入可显著影响体系的热猝灭性能.     

Comparative study of the forward and backward methods for calculating jet properties in pp collisions at s~(1/2)=7 TeV

We propose a forward method based on PYTHIA6.4 to study the jet properties in ultra-relativistic pp collisions.In the forward method,the partonic initial states are first generated with PYTHIA6.4 and then hadronized in the Lund string fragmentation model,and finally the hadronic jets are constructed from the created hadrons.Jet properties calculated with the forward method for pp collisions at √s=7 TeV are comparable to those calculated with the usual anti-kt algorithm(backward method)in PYTHIA6.4.The comparison between the backward and forward methods may contribute to the understanding of the partonic origin of jets in the backward method.     

Analysis of detection error for spot position in fiber nutation model

The influences of nutation trail accuracy,simplification of coupling model,spot position jitter,and power variation of incident light on the detection error are analyzed theoretically.Under the condition of satisfying the requirements,the nutation radius is less than 1.13μm,the accuracy of the nutation trail is less than 0.04μm,and the detection range is[?5μm,+5μm].The nutation frequency is 160 times spot position jitter frequency and 100 times intensity jitter frequency of incident light.The analysis is of great significance for determining nutation radius and frequency in the tracking system based on fiber nutation.     

Diffraction of relativistic vortex harmonics with fractional average orbital angular momentum

Vortex harmonics with fractional average orbital angular momentum are generated when a relativistic fractional vortex beam is incident on and reflected from an over-dense plane plasma target. A two-step model is presented to explain the far-field patterns of the harmonics. In the first step, a fundamental spot-shaped hole is produced during the hole-boring stage, and harmonics are generated simultaneously. In the second step, different order harmonics are diffracted by the hole and propagate to the far field. This process can be accurately described by the Fraunhofer diffraction theory. This work facilitates a basic recognition of fractional vortex beams.     

新媒体时代下化学实验教学与实验室管理探索

当今新媒体时代下,二维码和公众号技术虽然已经普遍成熟,但是其在化学实验教学和实验室管理方面的深层次应用尚处于探索阶段。本文结合目前高校实验教学特点,分析探索了二维码和公众号技术在化学实验教学和管理中的应用以及存在的问题。从学生和教师两方面出发,在同为辅助工具的基础上两者联用不仅促进了实验教学平台整体的运行效率和管理水平,而且在充分发挥教师主导作用的同时调动了学生的主观能动性,学习效果及实际教学效果亦日渐显著,为国内化学实验教学改革提供了帮助。