Electro-oxidation of Ascorbic Acid on PVP-stabilized Graphene Electrode

Polyvinylpyrrolidone-stabilized graphene(PVP-graphene) was synthesized and investigated as a modifier for the determination of ascorbic acid(AA).With PVP acting as stabilizer and dispersant,the resulting PVP-graphene material could disperse well into water.And the PVP-graphene modified glassy carbon electrode(PVP-graphene-GCE) showed an obvious electrocatalytical activity toward the oxidation of AA in a phosphate buffer solution(PBS,pH=7.0) with an oxidation potential of AA at 0.052 V vs.Ag|AgCl(sat.KCl).The calibration curve for AA was linear in a concentration range from 1.0×10-5 to 5.0×10-4 mol/L with a correlation coefficient of 0.9998.And the detection limit was found to be 1μmol/L.During the oxidation of AA,the π-π interaction of graphene plane with conjugated hexenoic acid-lactone in AA molecules might play a key role.As a result,an obvious decrease of overpotential was achieved at such a PVP-graphene electrode through a possible adsorption/enrichment process,which will probably trigger potential applications for the electroanalysis of some aromatic and heterocyclic compounds.     

Entanglement Dynamics of Three Qubits in the Non-Markovian Environments

We consider the entanglement dynamics of three two-level atoms interacting with independent structured non-Markovian reservoirs. The atoms are initially prepared in a mixed multipartite Greenberger—Horne—Zeilinger （GHZ）-type state. Based on the purity and non-Markovian reservoirs, we show that the reservoirs＇ entanglement can exhibit not only multipartite entanglement sudden birth but also entanglement sudden death, and the revival of atom entanglement is not always accompanied by the disentanglement of reservoirs. Meanwhile, we derive the quantitative criteria for multipartite revival and death phenomena and find multipartite entanglement sudden death and entanglement sudden birth simultaneous apparition time is independent of the initial three-qubit state.     

D and D_s in mass loaded flux tube

Heavy-light hadrons are studied in a mass loaded flux tube model. The study indicates that the dynamics of mesons and baryons containing a c quark is described well by the mass loaded flux tube. The hypothesis of good diquark-antiquark degeneracy is found reasonable in heavy-light quark systems. The spectrum of charmed (D) and charmed strange (Ds) mesons is systematically computed. D and Ds in 1D multiplets are predicted to have lower masses in comparison with other theoretical predictions. The predicted masses of the 1(13D1) and the 3(13D3) Ds agree well with those of recently observed Ds1(2700)± and DsJ(2860), respectively.     

柔性铰链的有限元法设计与分析

大变形、小应力、小中心漂移的柔性铰链的研制一直是柔性铰链研究的难题。本文在参考国外某款柔性铰链的基础上,利用V型结构设计、叠加理论和对称布置方法设计了一种新型的柔性铰链。针对这种柔性铰链的设计进行了概念性研究,建立了铰链的数学模型,研究了这种新型柔性铰链的性能。有限元方法分析表明,该设计方法增加了铰链柔性部分的长度,降低了它的中心漂移和最大应力,得到其最大转角约为16°,最大中心漂移为3.557μm,最大应力为499.8 MPa,满足了最初的设计指标要求。结果证明该铰链具有一定的实用价值。     

The Ferry Cover Problem on Regular Graphs and Small-Degree Graphs

The ferry problem may be viewed as generalizations of the classical wolf-goat-cabbage puzzle. The ferry cover problem is to determine the minimum required boat capacity to safely transport n items represented by a conflict graph. The Alcuin number of a conflict graph is the smallest capacity of a boat for which the graph possesses a feasible ferry schedule. In this paper the authors determine the Alcuin number of regular graphs and graphs with maximum degree at most five.     

边赋权图对策Myerson值的和分解

2003年,Gómez等在考虑社会网络中心性度量时,引入了对称对策上Myerson值的和分解概念,本文将这一概念推广到边赋权图对策上,给出了相应于边赋权图对策的组内Myerson值和组间Myerson值。其中边的权表示这条边的两个端点之间的直接通讯容量,组内Myerson值衡量了每个参与者来自它所在联盟的收益,而组间Myerson值评估了参与者作为其他参与者中介所获取的收益。本文侧重分析了边赋权图对策的组内Myerson值和组间Myerson值的权稳定性和广义稳定性, 并给出了这两类值的刻画。     

超网络博弈的位置值的公理化刻画

在图博弈中,Myerson假设只有连通的联盟才能获得完全的效用,而忽略连通联盟的具体结构.1996年,Jackson和Wolinsky提出了“网络情形博弈”的模型,拓展了Myerson的图博弈模型.它是利用值函数代替原来的特征函数以体现不同网络结构对合作结果的影响.考虑超网络情形博弈,它是网络情形博弈的自然推广,由三元组（N,H,v）所组成,这里v是值函数,用于描述在超网络（N,H）合作结构下的合作收益.2012年,van den Nouweland和Slikker利用四个公理给出了位置值的公理化刻画.通过分支有效性和局部平衡超边贡献性两个公理,给出了超网络博弈中位置值的公理化刻画.作为推论,得到了网络博弈中位置值的新刻画.     

共格外延的La_(0.7)Sr_(0.3)MnO_3薄膜的应变弛豫

厚度为7～100nm La0.7Sr0.3MnO3(LSMO)薄膜是由脉冲激光法生长在(001)(LaAlO3)0.3(Sr2AlTaO6)0.7(LSAT)衬底上.薄膜的结构演变是由高分辨X-射线ω-摇摆曲线及倒易空间(103)反射来表征.我们的结果表明所有的LSMO薄膜是共格生长在LSAT(001)上.对厚度大于(或等于)22nm的LSMO薄膜既显示可调制的单斜(MA)结构,也包含切应变弛豫诱导的有序畴结构和平面内超格子.薄膜的厚度依赖的结构畴宽,以及切应变对薄膜居里温度Tc的影响被仔细研究.作为对比,晶格失配对LSMO薄膜中周期畴形成的影响也被讨论.     

高温气冷堆堆芯中子时空动力学模拟计算

研究开发三维圆柱几何堆芯多群中子时空动力学改进准静态方法模拟计算程序.对给定的模块式高温气冷堆模型进行模拟计算.初始状态下,计算结果与中子扩散程序CITATION吻合很好.动态情况下,模拟堆芯反应性、堆内各能群中子平均注量率和堆芯相对功率等物理量随时间变化,计算结果与理论分析一致.     

多层介质膜光栅用高反射镜的严格耦合波分析

基于严格耦合波和增强透射矩阵的方法,提出了一种数值稳定的求解多层介质膜光学特性的机理模型.利用该模型计算了多层介质膜光栅用高反射镜的优化设计膜系.使用电子束热蒸发方式制备的多层介质膜光谱特性和理论设计的结果符合得很好,该严格耦合波模型是分析介质膜光学特性有效的稳定的数值求解方法.