Dynamics of an atom coupled through a parametric frequency converter with quantum and classical fields

In this communication we introduce a model of a two-level system which represents the interaction between an atom and external quantum and classical electric fields through a parametric frequency converter. We show that the system can be reduced to an effective Jaynes-Cummings model by adequate adjustment of the field coupling in the frequency converter. The atom dynamics and the atom-quantum field entanglement are then shown to be controlled through the classical field.     

Superfluid density and critical current density in superconducting cuprates with an extended d-wave pairing symmetry

The European Physical Journal B - We propose a novel dynamic link weight adjustment model, in which link weights on static network will be dynamically adjusted according to agents’ influence...     

改进的CS-UKF加速度方差自适应跟踪算法

针对基于当前统计模型的状态噪声协方差阵中的加速度方差调整方法对一般机动目标、非机动目标跟踪精度差的问题,研究其改进方法;在建立机动目标当前统计模型离散状态方程和雷达导引头离散观测方程的基础上;利用雷达导引头测量信息和位置预测值之间的扰动对加速度方差进行调整,提出了改进的加速度方差自适应调整无迹卡尔曼滤波跟踪算法;数字仿真验证了该算法对非机动目标、一般机动目标以及高机动目标均具有良好的跟踪效果。     

The structure of neutron-rich calcium isotopes studied by the shell model with realistic effective interactions

We study the structure of neutron-rich calcium isotopes in the shell model with realistic interactions. The CD-Bonn and Kuo-Brown (KB) interactions are used. As these interactions do not include the three-body force, their direct use leads to poor results. We tested whether the adjustment of the single particle energies (SPEs) would be sufficient to include the three-body correlations empirically. It turns out that the CD-Bonn interaction, after the adjustment of SPEs, gives good agreement with the experimental data for the energies and spectroscopy. For the KB interaction, both the SPEs and monopole terms require adjustments. Thus, the monopole problem is less serious for modern realistic interactions which include perturbations up to the third order. We also tested the effect of the non-central force on the shell structure. It is found that the effect of the tensor force in the CD-Bonn interaction is weaker than in the KB interaction.     

Quintessential adjustment of the cosmological constant

We construct a time dependent adjustment mechanism for the cosmological "constant" which could be at work in a late Friedmann-Robertson-Walker universe dominated by quintessence and matter. It makes use of a Brans-Dicke field that couples to the evolving standard-model vacuum energy density. Our explicit model possesses a stable late-time solution with a fixed ratio of matter and field energy densities. No fine-tuning of model parameters or initial conditions is required.     

Multi-radius geographical spatial networks: Statistical characteristics and application to wireless sensor networks

In this paper, a new kind of complex network model named multi-radius geographical spatial networks is proposed. We investigate statistical characteristics of this model and then map wireless sensor networks (WSNs) to it based on an efficient mechanism of broadcasting radius adjustment. Analysis and simulation show that WSNs working under this mechanism obtain longer lifetime and faster data delivering speed than those in traditional uniform radius WSNs.     

Changes in corneal asphericity after laser refractive surgery,including reflection losses and nonnormal incidence upon the anterior cornea

We tested the effects on laser ablation of reflection losses and nonnormal incidence on the anterior cornea. We measured presurgical and postsurgical corneal asphericity in 94 myopic eyes, comparing it with the corneal asphericity predicted by the Munnerlyn formula, modified or not, with an adjustment factor that takes into account the two effects mentioned above. The predictive power of the experimental results was stronger when we considered the adjustment factor. We propose to modify ablation algorithms by taking this adjustment factor into account, especially in customized corneal ablation, which needs high accuracy for correcting eye aberrations.     

Synchronizability of stochastic network ensembles in a model of interacting dynamical units

Synchronization is an important phenomenon which occurs in the dynamics of complex systems. Synchronized states emerge both from an adjustment of the system parameters and from an application of a proper external stimulus. In the present paper we study synchronized activity in a neural network model whose dynamics is driven by an external activation. In this context we are interested in its synchronizability, i.e. the existence of inputs causing the model system to synchronize. Furthermore, we investigate global synchronizability properties of stochastic network structure ensembles (instead of single realizations of a network architecture). We study the small world network, a model of preferential linking structure, and the classical Erd?s-Renyi random graph as particular examples of network topologies. Their synchronizability properties are investigated by analytical arguments and numerical simulations. Our analysis shows the emergence of synchronizable states of network ensembles for a wide range of the parameter values. In addition we observe and study the transition behaviour from synchronizability to nonsynchronizability.     

Establishment,maintenance, and re-establishment of the safe and efficient steady-following state

We present an integrated mathematical model of vehicle-following control for the establishment, maintenance, and re-establishment of the previous or new safe and efficient steady-following state. The hyperbolic functions are introduced to establish the corresponding mathematical models, which can describe the behavioral adjustment of the following vehicle steered by a well-experienced driver under complex vehicle following situations. According to the proposed mathematical models, the control laws of the following vehicle adjusting its own behavior can be calculated for its moving in safety,efficiency, and smoothness(comfort). Simulation results show that the safe and efficient steady-following state can be well established, maintained, and re-established by its own smooth(comfortable) behavioral adjustment with the synchronous control of the following vehicle's velocity, acceleration, and the actual following distance.     

Eighth-order rational harmonic mode-locked fiber laser with amplitude-equalized output operating at 80 Gbits/s

We report the generation of an 80 Gbit/s pulse train by an eighth-order rational harmonic mode-locking technique. Equalized pulse-train amplitude is achieved by proper adjustment of the dc bias point and the 10 GHz modulation strength applied to the cavity-loss modulator. A numerical model is developed to simulate the properties of the generated 80 Gbit/s pulse train. The simulated results are well supported by the experimental measurements.     

Influence of laser polarization on ocular refractive parameters after refractive surgery

We provide an adjustment factor for ablation algorithms used in photorefractive laser surgery that takes into account how laser polarization in reflection losses affects the cornea. We evaluate the influence of this factor on corneal radius and asphericity after surgery, showing that it is significant for visual performance (effective visual acuity is reduced) and for the correction of eye aberrations. Our data indicate that this adjustment factor should be included in the ablation algorithms (depending on the polarization state of each laser device) that are proposed for customized corneal ablation, which need great accuracy for minimization of eye aberrations.     

附有高程约束的三维平差方法研究

当前加速器准直主要采用激光跟踪仪进行三维空间位置测量,三维测量数据用三维平差方法计算从理论上讲更为严密,但在实践中却发现存在误差累积现象,其中在高程方向的误差累积十分明显。为了控制三维平差高程方向的误差累积,研究将大地水准面做为基准引入测量和数据处理过程之中,获得基于大地水准面的高程测量数据,用高程数据构建约束条件方程,进行附有高程约束的三维平差。以激光跟踪仪为例给出了三维平差函数模型,研究了约束方程的构建方法,推导了附有高程约束的三维平差计算公式。研究了附有高程约束的三维平差函数模型的两种应用方法,通过模拟计算展示了这两种方法对高程方向误差累积的控制效果。最后对一组实测数据采用多种平差方法进行计算对比,结果显示附有高程约束的三维平差相比无高程约束的三维平差能够更有效的控制平差中高程方向的误差累积。     

三相三电平VIENNA整流器中点电位波动混合抑制方法

针对三相三电平VIENNA整流器中点电位波动问题,建立了中点电流的数学模型,分析了中点波动形式、并结合中点电流数学模型分析了中点电位波动的根本原因,针对传统固定调节因子法抑制中点电位波动效果较差的缺点,提出了一种结合动态调节因子与电容偏差调节的混合抑制方法,给出了6扇区下偏差调节量和动态调节因子表达式,然后通过查表法将6扇区对应动态调节量注入到调制波中,实现了中点电位尤其三次基频波动的自动抑制,进一步修正后的混合抑制法还可有效抑制电容参数和负载不对称导致的中点大幅度波动,实验结果验证了策略的可行性和有效性。     

Massive strings in higher-dimensional inhomogeneous spacetime

An inhomogeneous cosmological model with massive strings as source term is developed in a Kaluza-Klein type of spacetime where the usual space exhibits spherical symmetry and the extra dimension is taken in the form of a circle. When an arbitrary constant in our solution vanishes we get an inhomogeneous cosmological model for pure dust, which further reduces to some particular forms of well known homogeneous models under suitable adjustment of arbitrary constants. The dynamical behaviour of the model is studied and it is found that the extra space admits of dimensional reduction via the successive appearances of one minimum and one maximum throughout its evolution.     

遗传算法在跨超声速风洞总压控制中的应用

总压作为风洞控制中的重要流场参数,其调节性能是风洞控制系统能否满足试验要求的重要指标,为提高跨超声速风洞的总压控制水平,需对总压控制策略进行设计。针对某跨超声速风洞对总压控制系统提出的快速性和精确性要求,提出串级控制、智能PID控制和总压分段控制等方法,并利用MATLAB系统辨识工具箱对流场调节阶段的总压系统模型进行了辨识。提出将遗传算法应用于风洞流场调节阶段的PID控制器参数整定中,重点对基于遗传算法的PID控制原理和参数整定步骤进行介绍,并针对遗传算法的遗传算子进行了设计。系统仿真和风洞实际运行情况表明：该方法较常规PID参数整定与优化方法,具有更好的控制性能指标,满足总压控制系统精确性、快速性、鲁棒性等要求,为后续风洞建设和设备改造提供了新方法。     

Control of the polarization dependence of optically poled nonlinear polymer films

We demonstrate the possibility of controlling the symmetry properties of photoinduced chi((2)) macroscopic susceptibility in polymer films. Ellipsometric adjustment of the write beams allows one to monitor the macroscopic chi((2)) symmetry from a dipolar to an octupolar configuration. Experimental results are in agreement with an irreducible spherical tensor-based model jointly applied to the molecular beta hyperpolarizability and field tensors. We found a purely octupolar polarization-independent photoinduced second-harmonic-generation response in a Dispersed Red 1-methyl methacrylate thin film. Such a configuration, as generated by an octupolar tensor write field tensor made up of counterclockwise circularly polarized omega and 2omega beams, is not within the reach of the classical electric-field poling technique.     

Ferroelectric Phase Transition of first Order in BaTiO3

A microscopic model of BaTiO₃ is treated to describe static phenomena near the ferroelectric phase transition. In addition to the polarization, changes of the lattice constant at fixed pressure are also considered. That leads to a new explanation of the first order character of the transition, which is carried out not only qualitatively but also quantitatively. We investigate the dependence on pressure and external field. Agreement with the experiment through the adjustment of the parameters of the theory is obtained.     

四程放大自动准直系统数学模型研究

针对高功率激光装置四程放大系统的特点,利用矩阵光学原理,建立了四程放大准直系统的数学模型;基于此模型,设计了四程放大系统的准直调整方案;得出了近、远场偏移量与调整量关系的解析解. 关键词： 激光技术 光束准直 四程放大     

Extended synchrotron X-ray reflectivity study of a Sm-based layer buried into CdTe(001)

We present an extended X-ray reflectivity study of a Sm-based epitaxial layer buried into CdTe(001) in order to investigate its structure. The measured reflectivity is modelled over a wide range of momentum transfer and the adjustment of the calculated intensity gives quantitative information about the electron density and interplanar distance profiles along the surface normal. Complementary experiments of photoemission spectroscopy allow the interpretation of the in-plane electron density in terms of chemical composition. High resolution electron microscopy shows that the very strong chemical gradients deduced from the model result from an original topology of the layer.     

基于属性约简的应用服务器优化算法改进

优化参数配置是优化应用服务器性能的重要方面;基于传统参数调节的优化策略耗时耗力缺乏系统性和规律性;利用模块化思想针对目标决策函数对应用服务器参数进行分类,可构建条件属性约简模型;基于属性约简的应用服务器优化算法,可去除对于目标决策函数相对不重要的参数,并获得相对重要的参数,从而达到锁定目标重点调节,快速提高系统性能的目的;现有的约简模型优化算法多基于经典粗糙集理论,在等价关系的基础上构造分类,容易造成大量的信息破坏和流失;文章通过拓展等价关系到一般二元关系,利用广义粗糙集理论改良了基于模块化思想和属性约简模型的应用服务器优化算法,通过定义辨识函数对条件属性进行约简,再结合依赖度计算,得到最终目标参数。