单光子纠缠态的纠缠浓缩(英文)

通过分析光学分束器对单光子态的作用特点,描述了一个利用单光子态和真空态制备纠缠单光子态的方法;提出了一个实现单光子纠缠态纠缠浓缩的方案。在这个方案中,两个单光子部分纠缠态被用来作为量子信道,通过利用光学分束器作用和单光子探测器探测完成了这个纠缠浓缩的过程。结果表明,对于单光子纠缠态,利用这种方法总有一定的几率可以从部分纠缠纯态中提纯出最大纠缠态。     

投资内生化的房地产投入占用产出局部闭模型及其应用

房地产在国民经济中占据特殊地位,为全面反映房地产与国民经济间的相互联系和促进关系,设计和构造了房地产投入占用产出表.分析表中数据可知,房地产发展对国民经济的主要影响与其他生产部门不同,主要通过增加企业毛盈余和政府收入进而拉动投资增长,最终实现经济增长.鉴于传统投入产出模型不能对此进行有效刻画,提出新的将投资内生化的投入产出局部闭模型.应用模型测算房地产对经济的拉动效应,得出的测算结果与传统模型相比明显偏大.     

香水中邻苯二甲酸酯总量测定及其暴露评估

建立了快速测定香水中邻苯二甲酸酯(PAEs)的前处理方法。将香水中的PAEs水解为邻苯二甲酸(PA),再利用磷酸三丁酯萃取酸化液中的PA,使用高效液相色谱-二极管阵列检测器定量分析,并评估了PAEs的暴露量。实验考察并优化了影响PAEs水解率的因素,包括KOH的浓度和体积、乙醇的体积、水解时间和温度,优化后的水解条件:10 mL 4 mol/L KOH,1 mL乙醇,水解时间20 min,水解温度80℃。目标分析物的线性范围为3~240μmol/L(R2=0.999 1),LOD和LOQ分别为4.6μmol/kg和5.9μmol/kg,加标回收率为83.4%~92.7%,日内和日间精密度(RSD)不大于6.8%(n=5)。选择35种香水进行测定,PAEs总量范围在LOD~77.738 mmol/kg之间,成年女性经由香水途径接触PAEs的最大暴露水平为0.474 2μg/(kg·d)。该方法前处理过程简单,可靠性高,适用范围广,可以作为检测香水中PAEs的新选择。     

基于虚功原理建立套管外挤力学模型

为了准确地描述侧向载荷作用下套管发生挤毁变形,假设在发生塑性变形时套管的受力变形区形状为对称的两个弧形,基于虚功原理建立侧向载荷作用下的套管损坏力学平衡关系,引入菲涅耳积分推导出套管损坏力学模型.并结合大庆油田工程实际进行了套管挤毁实验,得出新公式的平均相对误差远远小于API公式的平均相对误差,从能量角度出发,为研究在外挤载荷下套管挤毁变形提供新的研究方法,为以后研究相关设计提供参考.     

CdTe量子点-罗丹明6G荧光共振能量转移体系的构建及其应用研究

采用巯基化合物修饰的CdTe量子点构建了量子点(供体)-罗丹明6G(受体)荧光共振能量转移体系, 研究了CdTe量子点与牛血清白蛋白(BSA)的相互作用. 结果表明, CdTe量子点与BSA相互作用后提高了CdTe量子点-罗丹明6G 体系的荧光共振能量转移(FRET)效率, 减小了CdTe量子点和罗丹明6G分子间的距离(r), 证实BSA是通过其色氨酸(Trp)残基与CdTe量子点表面金属发生配位作用而直接结合到量子点表面的.     

X射线TICT在复合材料工件检测中的射束硬化拟合校正研究

X射线TICT中,X射线透射物质时,发生了能谱硬化现象。使图像重建时出现伪影。因此必须进行修正。文中对X射线硬化现象进行了分析,探讨了X射线TICT在检测复合材料工件中, X射线射束和与透射厚度的关系, 并根据Beer定律和X射线与物质作用的特点, 通过获取X射线射束和数据,首先拟合出射束和与透射厚度的关系式, 然后推导出X射线射束和校正为单色射线射束和的等效厚度与透射厚度的关系及其等效方法, 最终得出X射线TICT在检测复合材料工件中X射线等效单色射线的衰减系数的射束硬化拟合值, 再对此衰减系数拟合值进行卷积反投影重构, 即可有效消除X射线TICT在检测复合材料工件中射束硬化造成的影响。     

A new traffic model with the consideration of coupling effect with two lanes

This paper introduces a new two-lane high-order continuum model by embedding the two delay time scales continuum traffic model presented by Xue (2003 Phys. Rev. E 68 066123) into the multi-lane model proposed by Daganzo (1997 Transpn. Res. B 31 83) with the consideration of the coupling effect between the vehicles of two lanes in instantaneous traffic situation and lane-change effect. In the novel model, the coupling effect of two lanes and phenomena of lane change, which were not discussed in Daganzo's model and Xue's model, are taken into account. Numerical simulation shows that it is in accordance with real traffic flow. This obviously indicates that the new phenomenon and behaviour are analogous results as single lane presented by Xue, and the proposed model is more reasonable on two lanes. Furthermore, the generation rate between two lanes is also investigated. The results show that the formation and diffusion of traffic shock wave can be better simulated on two lanes.     

A viscous continuum traffic flow model with consideration of the coupling effect for two-lane freeways

In this paper, the viscous continuum traffic flow model for a single lane is extended to the traffic flow for two-lane freeways. The proposed model is a higher-order continuum model considering the coupling and lane changing effects of the vehicles on two adjacent lanes. It results from integrating the Taylor series expansion of the viscous continuum traffic flow model proposed by Ge (2006 Physica A 371 667) into the multi-lane model presented by Daganzo (1997 Transpn. Res. B 31 83). Our proposed model may be used to describe non-anisotropic behaviour because of lane changing in multi-lane traffic. A linear stability analysis is given and the neutral stability condition is obtained. Also, issues related to lane changing, shock waves and rarefaction waves, local clustering and phase transition are investigated through a simulation experiment. The simulation results show that the proposed model is capable of explaining some particular traffic phenomena commonly observable in real world traffic flow.     

Multiple car-following model of traffic flow and numerical simulation

On the basis of the full velocity difference (FVD) model, an improved multiple car-following (MCF) model is proposed by taking into account multiple information inputs from preceding vehicles. The linear stability condition of the model is obtained by using the linear stability theory. Through nonlinear analysis, a modified Korteweg-de Vries equation is constructed and solved. The traffic jam can thus be described by the kink--antikink soliton solution for the mKdV equation. The improvement of this new model over the previous ones lies in the fact that it not only theoretically retains many strong points of the previous ones, but also performs more realistically than others in the dynamical evolution of congestion. Furthermore, numerical simulation of traffic dynamics shows that the proposed model can avoid the disadvantage of negative velocity that occurs at small sensitivity coefficients λ in the FVD model by adjusting the information on the multiple leading vehicles. No collision occurs and no unrealistic deceleration appears in the improved model.