Degree of Freedom Analysis for Holographic MIMO Based on a Mutual-Coupling-Compliant Channel Model

Degree of freedom(DOF)is a key indicator for spatial multiplexing layers of a wireless channel.Traditionally,the channel of a multiple-input multiple-output(MIMO)half-wavelength dipole array has a DOF that equals the antenna number.However,recent studies suggest that the DOF could be less than the antenna number when strong mutual coupling is considered.We utilize a mutual-coupling-compliant channel model to investigate the DOF of the holographic MIMO(HMIMO)channel and give a upper bound of the DOF with strong mutual coupling.Our numerical simulations demonstrate that a dense array can support more DOF per unit aperture as compared with a half-wavelength MIMO system.

Coupled-channel cavity QED model and Semi-classical solution

A semi-classical scheme is presented to solve the coupled-channel cavity QED (CQED) model. Such model exhibits remarkable characteristics as shown by numerical calculations. A relation between the swing or angular velocity of the detuning and the motion of the atoms is discussed. With the augmentation of the optical field intensity or frequency, the atoms are trapped firstly and then they move stochastically and finally chaos sets in.

Dirac Coupled Channel Analyses of Proton Inelastic Scatterings from s-d Shell Nuclei

Proton inelastic scatterings from several s-d shell nuclei are analyzed using optical potential model and collective model in Dirac coupled channel formalism. The optical potential parameters obtained phenomenologically for the scatterings from the s-d shell nuclei are compared with each other for systematic Dirac analysis. Dirac equations are reduced to the second-order differential equations in order to obtain the Schroedinger equivalent effective central and spin-orbit optical potentials, and the surface-peaked phenomena are observed at the real effective central potentials for the scatterings from 22Ne, 20Ne and 24Mg. By analyzing the obtained effective spin-orbit potentials, it is confirmed that the spin-orbit interaction is a surface-peaked interaction. The first-order rotational collective models are used to describe the low-lying excited states of the ground state rotational bands in the s-d shell deformed nuclei, and the obtained deformation parameters are analyzed by comparing with each other, and compared with those obtained by using the nonrelativistic calculations. The obtained deformation parameters of Dirac phenomenological calculations for the s-d shell nuclei are found to agree pretty well with those of the nonrelativistic calculations using the same Woods-Saxon potential shape, even though the theoretical bases are quite different.

Linear Precoder Design for Correlated Rician Fading Channel Under Imperfect CSI

In this paper,we have modeled a linear precoder for indoor multiuser multiple input multiple output(MU-MIMO)system with imperfect channel state information(CSI)at transmitter.The Rician channel is presumed to be mutually coupled and spatially,temporarily correlated.The imperfection with CSI is primarily due to the channel estimation error at receiver and feedback delay amidst the receiver and transmitter in CSI transmission.Along with,the insufficient spacing between the antenna at transmitter and receiver persuades mutual coupling(MC)among the array elements.In addition,the MIMO channel is presumed to be jointly correlated(Weichselberger correlation model).When we look back on the existing precoder design,it considered spatial correlation alone disregarding joint correlation of antenna array elements.With all above assumption,we have designed a linear precoder which minimizes mean squared error(MSE)subjected to total transmit power constraint for MUMIMO system.The simulation results proven that proposed precoder shows substantial enhancement in bit error rate(BER)performance in comparison with the existing technique.The mathematical analysis corroborates the simulation results.

深中通道岛隧结合部波流特性及覆盖层稳定性试验研究

基于岛隧工程结合部与传统隧道、近岸陆地工程衔接存在明显差别,以及在设计上面临的新难题,为保证深中通道岛隧结合部沉管隧道覆盖层在极端恶劣条件下的安全性和可靠性,对结合部区域范围内波流特性和防护结构的稳定性进行了研究。通过开展物理模型试验,模拟了包括波浪和水流之间变化角度的水动力场,以及波流耦合作用护面块体稳定性;揭示了岛隧结合部波流耦合效应,总结了波高比(H_(s)′/H_(s))和流速比(U′/U)与相对流速(U/C)、波陡(H_(s)/L)、相对水深(d/L)和波流夹角(α)变化规律,并导出了相应的计算公式;同时通过多组试验对比优化,获得了护面块体最优稳定重量,导出了波流耦合作用下护面块体稳定重量的计算方法。研究结果不仅解决了深中通道重大工程的实际问题,也为今后海底沉管隧道覆盖层的建设提供基础数据和技术支撑。

开敞式粉砂淤泥质航道维护技术

开敞式粉砂淤泥质航道常年淤积,如何在维护方案优化中考虑淤积特性的影响,兼顾通航安全性与疏浚工程经济性,是业界关注的热点问题。采用实测资料分析与数值模拟相结合,针对某开敞式粉砂淤泥质航道建立考虑波流耦合的泥沙数学模型,对比多种维护疏浚方案年回淤量,评估不同疏浚指标对航道回淤量的敏感性。结果表明,开敞式粉砂淤泥质航道疏浚宽度的增加可有效减小年回淤量。研究成果可为开敞式粉砂淤泥质航道的维护方案优化提供参考。

A COUPLED 1-D AND 2-D CHANNEL NETWORK MATHEMATICAL MODEL USED FOR FLOW CALCULATIONS IN THE MIDDLE REACHES OF THE YANGTZE RIVER

A coupled one-dimensional （1-D） and two-dimensional （2-D） channel network mathematical model is proposed for flow calculations at nodes in a channel network system in this article. For the 1-D model, the finite difference method is used to discretize the Saint-Venant equations in all channels of a looped network. The Alternating Direction Implicit （ADI） method is adopted for the 2-D model at the nodes. In the coupled model, the 1-D model provides a good approximation with small computational effort, while the 2-D model is applied for complex topography to achieve a high accuracy. An Artificial Neural Network （ANN.） method is used for the data exchange and the connectivity between the 1-D and 2-D models. The coupled model is applied to the Jingjiang-Dongting Lake region, to simulate the tremendous looped channel network system, and the results are compared with field data. The good agreement shows that the coupled hydraulic model is more effective than the conventional 1-D model.

黄河三门峡水库水沙电耦合模型研究及应用

为实现多沙河流水库短期兴利效益和长期减淤效益的平衡,采用数学模型研究水库减淤与发电综合效益具有重要意义。充分考虑水沙输移和河床变形的耦合作用,通过结合一维水沙计算模块、水库调度模块以及发电计算模块,建立了考虑水库调度的水沙电耦合计算模型。将该模型应用到三门峡水库,采用2019水文年和2020水文年实测水沙资料分别对模型进行率定及验证。并应用该模型研究了不同水沙条件和调度方式对水库冲淤和发电的影响。计算结果表明:各测站流量、水位以及含沙量的计算过程与实测过程符合较好,发电量计算值误差均在15%以内,该模型能较为准确地模拟库区冲淤及电站发电过程;较丰水枯沙过程,其余3种典型水沙条件下冲淤量和发电量变幅分别达129%~360%及18%~52%,受入库水沙条件影响大;降低非汛期起调水位有利于控制非汛期库区淤积,提高汛期敞泄的临界入库流量有利于提高减淤及发电综合效益。

Disentangling the nature of resonances in coupled-channel models

We present severM possible hadronic states found in coupled-channel models within the on-shell approx- imation. The interaction potential is constructed as a sum of the tree-level Feynman diagrams calculated with the effective Lagrangians. Based on the recent empirical data, we illustrate the possible existence of severM baryonic and mesonic states with definite quantum numbers in the model. We give their properties for the purpose of further study and discuss the potential of finding them in future experiments.

城市洪涝模型及CPU-GPU异构并行计算技术研究进展

在全球气候变暖和城市化背景下,城市洪涝问题日益严峻。为尽可能减少城市洪涝灾害造成的损失,提高城市对突发性强降雨事件的应急处理水平,开展城市洪涝数值模拟技术研究具有十分重要的意义。本文从城市洪涝精细化和高效模拟角度出发,综述了城市洪涝模型、CPU-GPU异构并行计算的研究进展,系统总结了产汇流模型、一维河道管网模型、二维地表模型、耦合模型、快速城市洪涝模型的构建方法和CPU-GPU异构并行计算的关键技术。针对当前城市洪涝模型研究中的不足之处,需要开展城市洪涝过程全物理机制模拟研究,深入分析全水动力城市洪涝模型的适用性、模拟精度和计算效率;还需基于异构并行计算技术,实现城市洪涝模型一维河道管网、二维地表淹没的快速模拟,为城市暴雨洪涝精细化与高效模拟奠定基础。

Mathematical modeling of the biphasic dopaminergic response to glucose

In this work, we specify potential elements of the brain to sense and regulate the energy metabolism of the organism. Our numerical investigations base on neurochemical experiments demonstrating a biphasic association between brain glucose level and neuronal activity. The dynamics of high and low affine KATP channels are most likely to play a decisive role in neuronal activity. We develop a coupled Hodgkin-Huxley model describing the interactive behavior of inhibitory GABAergic and excitatory dopaminergic neurons projecting into the caudate nucleus. The novelty in our approach is that we include the synaptic coupling of GABAergic and dopaminergic neurons as well as the interaction of high and low affine KATP channels. Both are crucial mechanisms described by kinetic models. Simulations demonstrate that our new model is coherent with neurochemical in vitro experiments. Even experimental interventions with glibenclamide and glucosamine are reproduced by our new model. Our results show that the considered dynamics of high and low affine KATP channels may be a driving force in energy sensing and global regulation of the energy metabolism, which supports central aspects of the new Selfish Brain Theory. Moreover, our simulations suggest that firing frequencies and patterns of GABAergic and dopaminergic neurons are correlated to their neurochemical outflow.

多水源补给的宿迁市黄河故道水量-水质耦合优化调控

为了实现黄河故道水量和水质双重保障目标下的耦合优化调控,需要综合考虑水量补给渠道、水质改善目标、经济成本和技术难度等多重因素。研究基于黄河故道11级梯级蓄水工程和骆马湖、中运河、洪泽湖对黄河故道的补给关系,充分利用和优化分配周边水系水源,通过建立水量-水质耦合模型,开展多种水资源配置方案的数值模拟与方案比选,提出多水源补给的黄河故道优化调度方案。结果表明:在“高水高用、低水低用”的基础上每月增加小额生态补水量(0.42亿~0.52亿m3),成本适中、技术难度低,且水质改善效果较好,2018年(现状年)和2025年(规划水平年)水质综合改善率分别为22%和9%,水质总体达标率分别为82%和93%,调水成本分别比单一水源(“高水”)成本降低16%和24%。

冰-水耦合作用下流冰对明渠的撞击破坏响应分析

为研究水介质中流冰对输水明渠的撞击影响,基于流固耦合的计算方法,运用LS-DYNA软件对水介质中流冰与明渠的撞击过程进行非线性有限元仿真,并通过几何比尺为1∶10进行模型试验验证。以流冰与明渠碰撞角度、流冰厚度、明渠衬砌混凝土强度等级为变量,探究其对流冰碰撞输水明渠的影响规律。结果表明:碰撞角度为90°工况下的明渠衬砌撞击区的最大等效应力与X方向最大位移分别是38.66°,45°,63.43°工况平均峰值的3.01倍和4.19倍,且90°工况下明渠衬砌撞击区发生了约为5.72×10^(-6)m的损伤变形,而38.66°,45°,63.43°工况下的损伤变形约0~4.78×10^(-7)m,表明倾斜的坡面可以有效减小流冰对明渠撞击区的撞击力、位移及损伤变形;流冰厚度对明渠衬砌撞击的最大等效应力与X方向最大位移呈现出近似的线性关系;流冰对明渠衬砌撞击的最大等效应力与X方向最大位移随着混凝土强度等级的增大而逐渐减小,两者呈现出近似的线性关系。综合分析所模拟的不同工况可以发现,冰渠之间的水由于受到冰运动时的挤压作用而预先产生一个高压力场,在求解分析时应充分考虑,不可忽略;同时,试验值与模拟值基本吻合,表明数值模拟仿真模型准确可靠。

整辊式板形仪通道耦合影响系数的标定计算模型

整辊式板形仪是冷轧带钢生产的高端仪器装备,在板形检测过程中存在通道耦合问题,准确确定影响系数是进行信号解耦的关键。根据整辊式板形仪的结构变形特点,采用弹性力学叠加原理和影响系数方法,提出通道耦合与信号解耦的机理模型。根据标定原理和方法,通过严谨的数学力学解析,提出影响系数的标定计算模型,将标定输出的电信号数字量转换为力学意义上的影响系数。标定实验证明,加载通道仅对左边两个通道和右边两个通道有明显影响,对其他通道的影响可以忽略不计。一般地,加载通道对左一、右一通道的影响系数约为0.15,对左二、右二通道的影响系数约为0.008,对其他通道的影响系数几乎为零。采用本方法确定的影响系数进行解耦,可以精确消除通道耦合的影响。对某1450 mm冷轧带钢轧机的工业应用证明,解耦的效果在带钢边部更为显著,使边部板形由松边变为紧边或紧边更紧。一般地,解耦可使边部板形纠正2.0~2.5 I的测控偏差。通过解耦,可以明显提高板形检测和控制的精度,获得良好的实物板形。

主槽一维和滩地二维侧向耦合洪水演进模型

为实现对复式河道大尺度漫滩洪水的快速模拟,结合洪水在滩槽行洪特点和河道一维、二维水动力学模型研究成果,在主槽与滩地分别划分为矩形和三角形网格,以左右滩唇为分界实现两网格系统嵌套;建立主槽一维水动力学数学模型,内插大断面间网格处的水力因子,在滩地采用简化的二维水动力学模型模拟滩槽间、滩地网格间水量交换,实现主槽一维与滩地二维模型侧向耦合。利用黄河下游"96·8"大洪水实测资料,对花园口至夹河滩河段洪水演进过程验证,结果表明该方法模拟精度较高,能够利用该模型模拟复式河道大漫滩洪水过程。

三维空间MIMO信道接收天线阵列互耦效应及系统容量分析

针对非频率选择性瑞利衰落MIMO(multiple-input multiple-output)信道,建立了接收天线阵列的三维空间信道模型,将MIMO的一般信道建模推广到三维空间域。在建模过程中利用天线阵列在互耦效应下的等效网络模型,推导出三维空间域模型下的互耦相关性的通用表达式,阐明了互耦效应下相关性与无互耦相关性之间的关系。应用通用表达式分析了当接收端为不同的天线阵列结构时,入射信号的中心到达角和角度扩展分别对于在互耦效应下信道容量的影响。分析结果验证了不同的角度扩展对于互耦相关性的影响,揭示了在互耦效应下影响系统容量的主要因素为入射信号的平均中心到达角。

大孔道形成与演化过程流固耦合模拟

为描述与认识油藏大孔道的形成与演化规律,建立了一套流固耦合数学模型。该数学模型由储集层渗透率演化模型与油藏流体渗流方程耦合而成,其中储集层渗透率的变化模型为渗透率与累计线流量的关系方程,反映了大孔道的演化过程。在此基础上,开发了模型求解软件。通过对正韵律概念模型的模拟计算,得出了大孔道在地层中的形成与演化规律:随着含水率的增加大孔道逐渐发育,含水率越高,大孔道越明显;大孔道主要发育在近井地带和主流线上;大孔道在正韵律厚油层底部发育;渗透率级差越大,注水过程中越容易形成大孔道;注采不均衡性导致在注采强度较大的方向上容易形成大孔道。实际模拟了胜利孤岛油田中二中30NB20井区Ng35大孔道的形成过程和特征,相应注水井实施调剖措施的效果进一步证实了大孔道的存在及本方法的可靠性。

地表河网-地下水流系统耦合模拟Ⅰ:模型

本文通过采用联立求解地表河流一维明渠非恒定渐变流与地下水拟三维非稳定流运动方程的技术路线,提出了地表河网与地下水流耦合模拟算法。该算法中地表河网流动分别由质量和动量守恒定律而建立的连续性方程和运动方程所组成;地下水流采用多层"拟三维"非稳定流模型,通过彼此间的水力联系,建立了地表河网-地下水流耦合模拟评价模型,该模型可用于地表水与地下水转化关系较为密切地区的水资源综合评价预测中。

利用脉冲耦合神经网络的高光谱多波段图像融合方法

针对高光谱图像波段众多、数据量大的特点,提出了一种基于脉冲耦合神经网络(Pulse Coupled Neural Networks,PCNN)模型的高光谱多波段图像融合方法.根据高光谱图像多输入的特点对原始PCNN模型进行了扩充,采用多通道PCNN模型来对输入图像进行非线性融合处理.通过分析传统变阈值衰减模型的特点及其不足,提出了修正的变阈值指数增加模型,以改善融合效果和降低PCNN运行的时间复杂度.利用记录点火时刻的赋时矩阵得到带有一定增强效果的融合结果图像.实验结果表明,该方法的融合效果要优于传统的主成分分析融合方法和小波变换融合方法.

三峡工程导截流数值实验室的建立及数值模拟(Ⅱ)

介绍了三峡工程导截流水流特性数值实验室的数值模拟技术及其应用情况。采用水深平均二维数学模型模拟坝址区大范围水域在导截流过程中水深平均的流场演变过程,利用二、三维耦合数学模型的概念,由二维数模成果给定三维模拟所需的初值条件及边界条件,使三维数值计算具有良好的精度和收敛速度。利用导截流数值实验室的实时数值试验,给出导截流过程关键部位的三维流速分布及水位分布,并与实测值吻合良好。这表明导截流水流特性数值实验室所采用的数值模拟技术合理可靠。