A New Approach to Measurement of Heating Rate of Trapped Ions

We propose a new scheme to estimate the heating rate of trapped ions in thermal states. By applying a controlled-U gate between the internal and the motional states of one of the trapped ions, we could obtain the mean phonon number from the population of the internal state of the ion. The imperfection due to fluctuations of the relevant parameters in real experiments is considered and we anaiyze the experimental feasibility of our scheme with sophisticated ion trap techniques.     

The Topological Structure of the SU（2） Chern-Simons Topological Current in the Four-Dimensional Quantum Hall Effect

In the light of the decomposition of the SU（2） gauge potential for I = 1/2, we obtain the SU（2） Chern-Simons current over S4, i.e. the vortex current in the effective field for the four-dimensional quantum Hall effect. Similar to the vortex excitations in the two-dimensional quantum Hall effect （2D FQH） which are generated from the zero points of the complex scalar field, in the 4D FQH, we show that the SU（2） Chern-Simons vortices are generated from the zero points of the two-component wave functions ψ, and their topological charges are quantized in terms of the Hopf indices and Brouwer degrees of Ф-mapping under the condition that the zero points of field ψ are regular points.     

Investigation of a Unified Chaotic System and Its Synchronization by Simulations*

We investigate a unified chaotic system and its synchronization including feedback synchronization and adaptive synchronization by numerical simulations. We propose a new dynamical quantity denoted by K, which connects adaptive synchronization and feedback synchronization, to analyze synchronization schemes. We find that K can estimate the smallest coupling strength for a unified chaotic system whether it is complete feedback or one-sided feedback. Based on the previous work, we also give a new dynamical method to compute the leading Lyapunov exponent.     

Error Tolerance in Constructing Cluster States

We consider the problem often encountered in constructing large cluster states, that is, the σx measurements in the depolarizing noise, and present a regulation to calculate the error propagation and the accumulation. Rohde et al. first pointed out the question [Phys. Rev. A 75 （2007） 010302（R）]. A quantitative analysis is given on the disadvantage influence of the probabilistic gate and noisy environment on the construction of two-dimensional （213） scalable cluster states. Positivity of partial transpose criteria is used to predict whether the final state is distillable or not. A critical value on the error tolerance in constructing cluster states is determined, which could be used as a test-bed for successful construction of scalable 2D cluster states. Furthermore, our quantitative analysis would also be helpful to find optimal approach to suppress the noise accumulation.     

Bidirectional Mapping between a Biphoton Polarization State and a Single-Photon Two-Qubit State

How to manipulate （operate or measure） single photons efficiently and simply is the basic problem in optical quantum information processing. We first present an efficient scheme to transform a biphoton polarization state to a corresponding single-photon state encoded by its polarization and spatial modes. This single-photon state carries both the information of the controlled and target photons. It will make the realization of bipartite positive- operator-valued measurements efficiently and simply. Moreover, the inverse transformation from the single-photon state back to the corresponding biphoton polarization state is also proposed. Using both the transformations, the realization of the arbitrary two-qubit unitary operation is simple with an M-Z interferometer. All the schemes are feasible with the current experimental technology.     

硝酸酯热分解的机理分析

使用加速量热仪研究硝酸正丙酯（NPN）、硝酸异丙酯（IPN）和硝酸异辛酯（EHN）的热分解过程。分析了在绝热条件下热分解反应动力学, 根据实验数据计算出表观活化能、指前因子和反应热等参数。根据NPN、IPN和EHN热分解的起始温度和反应热数据,给出了三种硝酸酯在75℃时的反应风险指数,分析得到三种物质的热失稳风险度。分别在B3LYP/6-31+G(2df,2p)和B3P86/6-31+G(2df,2p)的理论水平下,计算得到NPN、IPN和EHN的O-NO2键离解能(BDE)。由NPN、IPN和EHN的O-NO2键离解能在很大程度上符合由加速量热仪测试得到的活化能,推知三种硝酸酯的热分解反应只是单分子O-NO2键的均裂反应。     

分子电性作用矢量法用于取代芳烃的构效关系研究

基于定量结构-活性相关(QSAR)研究取代芳烃类化合物的性质具有重要意义。采用分子电性作用失量(MEIV)表征取代芳烃类有机毒物的分子结构,运用多元线性回归建立定量结构毒性相关(QSTR)模型,同时采用逐步回归结合统计检测筛选模型变量,建立了25个取代芳烃类有机污染物结构与呆鲦鱼(Pimephales Promelas)96h半数致死浓度 回归方程。另外采用内部及外部双重验证的办法深入分析和检验模型的稳定性。建模的复相关系数(Rcum2)、留一法(LOO)交互校验复相关系数(RCV2)和外部样本校验复相关系数(Qext2)分别为0.926、0.870和0.875。表明用MEIV表征取代芳烃类有机物分子结构信息较好,所建QSTR模型的稳定性和预测能力良好。     

基于PHI影像敏感波段组合的冬小麦条锈病遥感监测研究

利用ASD地面非成像光谱仪对不同严重度的冬小麦条锈病的冠层光谱反射率进行测定,同时调查病情指数。通过对地面实测的46组病情指数与相应的光谱反射率进行相关性分析,筛选出了小麦条锈病在350～1 500 nm的敏感波段。结合多时相的高光谱航空飞行遥感图像数据的特点和规律,最终选择红波段的620～718 nm与近红外波段的770～805 nm为条锈病在PHI影像上的敏感波段。并利用620～718 nm和770～805 nm的平均光谱反射率与相应的病情指数建立了多元线性回归模型:DI=19.241 R_1—2.207 R_2+12.274,验证结果表明,该模型的历史拟合度很好。并利用此模型最终在PHI影像上成功的实现了对冬小麦条锈病发生程度与发生范围的监测。     

基于油液原子光谱多维时间序列模型的机械磨损状态监测研究

提出了一种利用润滑油原子光谱分析技术对机械磨损状态进行监测的新方法。对磨合期润滑油原子光谱数据建立多维时间序列模型并视为标准模型,将新数据通过此模型后得到残差并选择残差方差阵元素作为新数据所属磨损状态的特征。然后,利用主成分分析法对高维特征进行降维,提取前三个主成分构成对应磨损状态的特征向量。最后,利用欧式距离度量对测试样本进行分类,达到了对机械磨损状态识别的目的。利用上述方法,通过对某型履带车辆发动机台架实验的光谱数据进行分析,对发动机磨损状态进行了有效识别,从而证明了所提方法的有效性。结果表明,将多维时间序列模型引入油液光谱分析技术,能够实现光谱信息的有效融合,提高机械磨损状态监测的准确性。     

精细积分方法的发展与扩展应用

钟万勰院士于1991年首先提出计算矩阵指数的精细积分方法,其要点是2^N类算法和增量存储。精细积分方法可给出矩阵指数在计算机意义上的精确解,为常微分方程的数值计算提供了高精度、高稳定性的算法,现已成功应用于结构动力响应、随机振动、热传导以及最优控制等众多领域。本文首先介绍矩阵指数精细积分方法的提出、基本思想和发展;然后依次介绍在时不变/时变线性微分方程、非线性微分方程以及大规模问题求解中发展起来的各种精细积分方法,分析了其优缺点和适用范围;最后介绍了精细积分方法的基本思想在两点边值问题、椭圆函数和病态代数方程等问题的扩展应用,进一步展示了该思想的特色。