Orthogonal Frequency Division Multiplexing Adaptive Technology for Multinode Users of Seawater Channel Based on Inductively Coupled Mooring Chain

As an important part of buoy-type ocean monitoring systems,the inductively coupled mooring chain solves the problem of data cotransmission through the multinode sensors that it carries,which is significant for the rapid acquisition of fish,hydrology,and other information.This paper is based on a seawater channel transmission model with a depth of 300 m and a bandwidth of 2 MHz.An orthogonal frequency division multiplexing(OFDM)technology is used to overcome the multipath effect of signal transmission on a seawater medium.The adaptive technology is integrated into the OFDM,and an improved joint subcarrier and bit power allocation algorithm is proposed.This algorithm solves the problem of dynamic subcarrier allocation during the cotransmission of underwater multinode user data in seawater channels.The results show that the algorithm complexity can be reduced by 0.18126×10^(-2)s during one complete OFDM system data transmission by the improved greedy algorithm,and a total of 216 bits are transmitted by the OFDM.The normalized channel capacity can be improved by 0.012 bit s^(-1)Hz^(-1).At the bit error ratio(BER)of 10^(-3),the BER performance can be improved by approximately 6 d B.When the numbers of users are 4 and 8,the improved algorithm increases the channel capacity,and the higher the number of users,the more evident the channel capacity improvement effect is.The results of this paper have an important reference value for enhancing the transmission performance of inductively coupled mooring chain underwater multinode data.

Adjustable half-skyrmion chains induced by SU(3)spin-orbit coupling in rotating Bose-Einstein condensates

The ground state properties of the rotating Bose–Einstein condensates(BECs) with SU(3) spin–orbit coupling(SOC)in a two-dimensional harmonic trap are studied. The results show that the ferromagnetic and antiferromagnetic systems present three half-skyrmion chains at an angle of 120°to each other along the coupling directions. With the enhancement of isotropic SU(3) SOC strength, the position of the three chains remains unchanged, in which the number of half-skyrmions increases gradually. With the increase of rotation frequency and atomic density–density interaction, the number of halfskyrmions on the three chains and in the regions between two chains increases gradually. The relationships of the total number of half-skyrmions on the three chains with the increase of SU(3) SOC strength, rotation frequency and atomic density–density interaction are also given. In addition, changing the anisotropic SU(3) SOC strength can regulate the number and morphology of the half-skyrmion chains.

Spin transport in a chain of polygonal quantum rings with Dresselhaus spin-orbit coupling

Using a transfer matrix method, we investigate spin transport through a chain of polygonal rings with Dresselhaus spin-orbit coupling（DSOC）. The spin conductance is dependent on the number of sides in the polygons. When DSOC is considered in a chain which also has Rashba spin-orbit coupling（RSOC） of the same magnitude, the total conductance is the same as that for the same chain with no SOC. However, when the two types of SOC have different values, there results a unique anisotropic conductance.

Coupling Study on the Problem Chain Teaching Mode and Moral Education Construction in Primary and Secondary Schools

The construction of moral education in primary and secondary schools is facingmany dilemmas,such as formalism,passivity,task-type,Tacitus trap and new media interaction.There is a high degree of coupling between the progressive,stepped and interlocking supply of Problem Chain mode and the demand of moral education construction in primary and secondary schools.Problem Chain mode is helpful to solve the problems of teaching content,teaching effects and educational object in moral education construction in primary and secondary schools.

THE CONVERGENCE OF NONHOMOGENEOUS MARKOV CHAINS IN GENERAL STATE SPACES BY THE COUPLING METHOD

We investigate the convergence of nonhomogeneous Markov chains in general state space by using the f norm and the coupling method,and thus,a sufficient condition for the convergence of nonhomogeneous Markov chains in general state space is obtained.

Coupling of Cutoff Modes in a Chain of Nonlinear Metallic Nanorods

We study the coupling of cutoff modes in a chain of metallic nanorods embedded in a Kerr nonlinear optical medium with strong near-field interactions analytically. Based on a quasidiscreteness approach, we derive a system of two coupled nonlinear Schrbdinger equations governing the evolution of the envelopes of these modes. It is shown that this system supports a variety of subwavelength plasmonic lattice vector solitons of the bright- bright, bright-dark, dark-bright, and dark-dark type through a cross-phase modulation. It is also shown that the existence of different solitons depends strongly on the gap width scaled for the rod radius and the type of nonlinearity of the embedded medium.

Vortex chains induced by anisotropic spin-orbit coupling and magnetic field in spin-2 Bose-Einstein condensates

We investigate the anisotropic spin-orbit coupled spin-2 Bose-Einstein condensates with Ioffe-Pritchard magnetic field.With nonzero magnetic field,anisotropic spin-orbit coupling will introduce several vortices and further generate a vortex chain.Inside the vortex chain,the vortices connect to each other,forming a line along the axis.The physical nature of the vortex chain can be explained by the particle current and the momentum distribution.The vortex number inside the vortex chain can be influenced via varying the magnetic field.Through adjusting the anisotropy of the spin-orbit coupling,the direction of the vortex chain is changed,and the vortex lattice can be triggered.Moreover,accompanied by the variation of the atomic interactions,the density and the momentum distribution of the vortex chain are affected.The realization and the detection of the vortex chain are compatible with current experimental techniques.

Design Method of an Ocean Induction Coupling Chain Communication System that Resists the Multipath Effect of a Seawater Channel

In this study,a mathematical model of multipath channels is established,and the delay parameters of 10-path models are calculated at 300 m.A multipath-channel hardware simulator based on a field programmable gate array(FPGA)is designed and verified at 100 k Hz,200 k Hz,500 k Hz,1 MHz,and 24 MHz transmission frequencies.According to the characteristics of the ocean induction coupling chain channel,the orthogonal frequency-division multiplexing(OFDM)algorithm parameters are designed by referring to the wireless communication protocol.The appropriate length cyclic prefix(CP)is added in the OFDM symbol to resist the multipath effect of the seawater channel,and the FPGA hardware transceiver based on the OFDM algorithm is realized.The hardware platform of the ocean induction coupling chain communication system is developed to resist the multipath effect of the seawater channel and tested at 24 MHz.The experimental results show that 800 ns is the best CP length for the developed system,which can effectively resist the multipath effect,with a signal-to-noise ratio above 24 d B and a bit error rate below 1%.This study provides a hardware simulation test platform and an effective method to resist the multipath effect of a seawater channel and improve the transmission performance of the seawater channel.

Mode stability analysis in the beam-wave interaction process for a three-gap Hughes-type coupled cavity chain

Based on space-charge wave theory, the formulae of the beam-wave coupling coefficient and the beam-loaded conductance are given for the beam-wave interaction in an N-gap Hughes-type coupled cavity chain. The ratio of the nonbeam-loaded quality factor of the coupled cavity chain to the beam quality factor is used to determine the stability of the beam-wave interaction. As an example, the stabilities of the beam-wave interaction in a three-gap Hughes-type coupled cavity chain are discussed with the formulae and the CST code for the operations of the 2π, π, and π/2 modes, respectively. The results show that stable operation of the 2π, π, and π/2 modes may all be realized in an extended-interaction klystron with the three-gap Hughes-type coupled cavity chain.

Brownian localization:A generalized coupling model yielding a nonergodic Langevin equation description

A minimal system-plus-reservoir model yielding a nonergodic Langevin equation is proposed, which originates from the cubic-spectral density of environmental oscillators and momentum-dependent coupling. This model allows ballistic diffusion and classical localization simultaneously, in which the fluctuation-dissipation relation is still satisfied but the Khinchin theorem is broken. The asymptotical equilibrium for a nonergodic system requires the initial thermal equilibrium, however, when the system starts from nonthermal conditions, it does not approach the equilibration even though a nonlinear potential is used to bound the particle, this can be confirmed by the zerotb law of thermodynamics. In the dynamics of Brownian localization, due to the memory damping function inducing a constant term, our results show that the stationary distribution of the system depends on its initial preparation of coordinate rather than momentum. The coupled oscillator chain with a fixed end boundary acts as a heat bath, which has long been used in studies of collinear atom/solid-surface scattering and lattice vibration, we investigate this problem from the viewpoint of nonergodicity.

Synchronization of N different coupled chaotic systems with ring and chain connections

Synchronization of N different coupled chaotic systems with ring and chain connections is investigated. The New system, the Chen system, the Lii system, the Lorenz system, and the Rossler system are used as examples in verifying effectiveness of the method. Based on the Lyapunov stability theory, the form of the controller is designed and the area of the coupling coefficients is determined. Simulations indicate that global synchronization of the N different chaotic systems can be realized by choosing appropriate coupling coefficients by using the controller.

装备制造业产业链、创新链、人才链“三链”耦合机制和协调研究——以陕西省为例

基于2013—2021年陕西省数据,通过构建陕西省装备制造业“三链”评价指标体系,运用耦合协调度模型和灰色关联度模型探究装备制造业“三链”的耦合协调度等级和耦合协调作用机制。结果发现:(1)陕西省装备制造业“三链”耦合协调发展状况总体稳定但存在波动性;(2)西安市装备制造业的耦合协调度处于中级水平,其余9个地级市耦合协调水平普遍偏低,呈现关中、陕南、陕北逐次降低的特征;(3)灰色关联度的测算和分析表明,总体上产业链、创新链和人才链之间发展关系密切,均处于高度关联的阶段。

甘肃积石山强震诱发同震滑坡-泥流灾害链联动耦合致灾效应

近年来黄土区强震和极端天气诱发的典型滑坡-泥流灾害链事件呈多发态势,链式地质灾害较单一灾害隐蔽性更强、波及范围更大、破坏程度更高、损失更严重,因此链式地质灾害防控研究一直是防灾减灾的热点和难点。2023年12月18日23时59分,甘肃省临夏州积石山县发生Ms 6.2级地震,震源深度10 km,已造成151人死亡。此次强震诱发青海省民和县中川乡草滩村—金田村滑坡-泥流链式灾害,共造成20人死亡,灾害链致死率占地震遇难总人数的13.5%。灾后通过遥感影像处理解译、文献资料整理甄别、无人机摄影航测、野外详细勘查访问、现场采样分析测试等手段方法,对滑坡-泥流链式灾害开展了较全面系统研究,恢复和重现滑坡-泥流灾害链的启动-滑动-流动-堆积过程,探讨提出“滑源区地表冻结阻隔滞水效应、滑源区沟谷整平回填滞水效应、滑源区台地灌溉渗流饱水效应、滑源区振动液化筛选启动效应、滑源区漏斗收口增速启动效应、流通区土体差异流动分选效应、流通区沟岸坍塌补给增流效应、流通区沟底冰封饱水加速效应、堆积区上游渗水补给增程效应”等9大联动耦合致灾效应。该研究可为链式地质灾害的形成机理与防控提供科学参考。

短链脂肪酸与糖尿病肾病关系的研究进展

糖尿病肾病是糖尿病的常见并发症之一,也是终末期肾病的常见病因。遗传因素、代谢紊乱、氧化应激、炎症反应等与糖尿病肾病的发生发展密切相关,但其发病机制尚不明确。短链脂肪酸是肠道菌群在宿主肠道内发酵膳食纤维主要的代谢产物,通过激活G蛋白偶联受体和去乙酰组蛋白受体参与调节食欲、调节糖代谢、调节脂质代谢、减轻炎症反应等一系列代谢过程,从而在糖尿病肾病的发生发展中可能起到关键作用。本文就短链脂肪酸与糖尿病肾病的关系和相关争议展开综述,旨在为了解短链脂肪酸在糖尿病的发生发展中的作用及为糖尿病肾病预防和治疗提供新的思路。

新发展格局下体育竞赛表演业产业链韧性提升的耦合逻辑、风险因素与实践方略

依托新发展格局,提升体育竞赛表演业产业链韧性是产业链现代化建设和体育竞赛表演业高质量发展的重要议题。本文运用文献资料法、逻辑分析法,结合产业链韧性的内涵将体育竞赛表演业产业链韧性拆解为补链、疏链和强链能力,具体表现为产业链在面对外部压力或风险时的冲击抵抗能力、恢复重构能力和核心竞争能力,此“三力要素”与构建新发展格局存在高度耦合。在此基础上识别新发展格局下体育竞赛表演业产业链韧性提升的风险因素:断链风险,核心技术自主创新能力不足;堵链风险,竞赛表演市场供求关系失衡;弱链风险,复合型体育人才本土供给不足。据此提出实践方略:补链方面,以完善的数字基础设施构建体育竞赛表演产业生态体系;疏链方面,以供给侧结构性改革调和体育竞赛表演市场供求关系;强链方面,以多元化渠道提升体育竞赛表演业人才要素流通效率。

中国制造业上市公司创新链与资金链耦合协调度的影响因素及其作用机制

围绕创新链部署资金链是提升中国创新体系整体效能的重要支撑,但中国创新体系仍存在着创新链和资金链(以下简称“‘两链’”)耦合程度不高而导致资金注入不及时、资金错配和科技成果转化率低等问题。然而,目前缺乏关于多因素对“两链”耦合协调的影响分析,尤其是在日益复杂的国际形势下,宏观因素以及企业内部治理情况对“两链”及其耦合协调度的影响机制有待深入分析。为促进中国“两链”耦合协调度和科技自主创新能力提高,为破解发展困境提供路径参考,基于2015—2021年中国制造业上市公司数据,将内部微观因素和外部宏观因素等多重因素纳入统一分析框架,运用耦合协调度模型和结构方程模型测算“两链”耦合协调的整体特征,探讨内外部因素对“两链”链耦合协调的影响机制和路径。结果发现:中国制造业上市公司的“两链”耦合协调度一直属于勉强协调发展型;“两链”发展水平的提升会加速推进“两链”耦合协调度的提升,而营商环境、创新环境以及公司治理的优化对“两链”发展水平的提高有直接促进作用,其中营商环境的作用效应最大、创新环境次之、公司治理较低,且前两者主要通过提升创新链整体效能的路径影响“两链”耦合协调度,后者则主要通过提升资金链整体效能的路径影响“两链”耦合协调度。基于此,从促进创新链与资金链协同发展以及充分利用地区宏观环境优势等方面提出推动中国制造业“两链”深度耦合的路径。

武陵山片区经济韧性与乡村振兴耦合协调时空演变研究

提升经济韧性与乡村振兴耦合协调水平对于实现共同富裕意义重大。在剖析经济韧性与乡村振兴耦合协调机理基础上,以武陵山片区30个县域单元为研究对象,综合运用核密度估计、耦合协调模型和空间马尔科夫链探析2011—2021年武陵山片区经济韧性与乡村振兴的耦合协调度及其时空演变特征。结果表明:武陵山片区经济韧性和乡村振兴的发展指数整体呈波动上升趋势,二者空间异质性显著;乡村振兴与经济韧性的耦合协调度呈逐年上升态势,空间上呈现出“西北部>东南部>中部”的分异格局;经济韧性滞后是阻滞大部分地区“乡村振兴—经济韧性”复合系统耦合协调水平提高的重要因素;武陵山片区耦合协调水平呈现“俱乐部”趋同现象,且高(低)水平邻域会提高本地耦合协调度向上(下)转移的概率。研究成果可为提升武陵山片区居民福祉、促进乡村振兴提供科学参考。

生态耦合下高技术产业集群横向创新链主体合作策略演化

从知识生态耦合视角对集群横向创新链主体合作策略演化展开研究,构建集群横向创新链主体和其邻居合作交互的演化博弈模型,进行系统稳定性分析,并考虑到网络嵌入性,对不同网络规模下的集群横向创新链主体合作策略进行动态演化仿真分析。研究发现,知识互补度能促进集群横向创新链主体间合作策略演化,并且该促进作用存在一个临界值,随着网络规模的增大临界值从0.5上升至0.8,但是网络规模越大网络演化的速度越慢。另外,知识重叠度对集群横向创新链主体间合作策略演化起抑制作用,不过存在一个较低的临界值0.4,当知识重叠度低于临界值时能够促进集群横向创新链主体合作;超过临界值后随知识重叠度的增加,对集群横向创新链主体合作的抑制作用增大,而且知识重叠度产生的作用不受网络规模的影响。

中国制造业产业链、创新链、资金链、人才链耦合协调发展:统计测度与演进态势

推动产业链、创新链、资金链、人才链融合发展是贯彻新发展理念、构建新发展格局的重要战略举措。基于2012-2021年中国30个省(区、市)的数据,利用耦合协调度模型测算分析中国制造业产业链、创新链、资金链和人才链(以下简称“四链”)的耦合协调度,运用核密度估计法和Dagum基尼系数考察其时间演进态势和空间差异来源,利用障碍度模型探究影响中国制造业“四链”耦合协调度的主要因素。研究结果表明:制造业“四链”耦合协调发展态势维稳向好,整体处于中度耦合协调阶段;创新链子系统发展持续滞后于产业链、资金链、人才链子系统;除“产业链-资金链”外,其他子系统“两两”间的耦合协调度均呈增长趋势;制造业“四链”耦合协调发展的区域差异大致呈现先上升后下降的倒“U”型趋势,主要来自区域间差异;目前要素层面临的主要障碍因子分别为产业链宽度、创新环境、资金周转能力和人才结构。最后,从鼓励区域间合作、优化创新激励机制、完善金融支持体系和引领人才回归实体经济部门等方面提出建议。

三重价值链耦合协调发展对企业绿色全要素生产率的影响

省内价值链、国内价值链和全球价值链(三重价值链)的融合发展,是畅通国内国际双循环,也是中国企业经济软着陆的关键抓手。在高质量发展有序推进的背景下,绿色全要素生产率成为衡量企业发展的重要指标,因此有必要探讨三重价值链耦合协调发展对企业绿色全要素生产率的影响。该研究利用世界投入产出表、中国多区域投入产出表、上市公司数据测算了三重价值链耦合协调度,基于SBM方法测算包含非期望产出的绿色全要素生产率,整合得到770家上市公司2012年、2015年和2017年的平衡面板数据,通过多维固定效应回归考察三重价值链耦合协调度对企业绿色全要素生产率的影响,研究结果表明:①存在三重价值链耦合协调度提升→GVC嵌入度深化→企业绿色全要素生产率增长的正向传播机制,但效果随着企业的要素密集度增加呈现递减趋势。②机制研究和异质性分析表明,前向耦合协调发展为企业绿色全要素生产率带来更有效和长期的动能,而后向耦合协调发展为劳动密集型企业带来短期显著的绿色生产率提升。基于此,该研究提出了布局本土产业、协调三链关系的相关政策建议:①地方政府应发挥主观能动性,评估本地企业优势,保证在政策制定上更加微观具体,劳动密集型的省份或行业有效利用三重价值链的协调发展为企业的转型升级奠定基础,为地方行业的协同发展打通阻碍。②在要素投入端,注重对地方高新技术企业的资源分配,同时区域间合作完成生产供应端的高度集成,增强前向耦合协调发展对于企业内涵式增长能力的促进效应,兼顾供应链流程的绿色环保标准。③加强省域间的政策协调性和交易通达性,提高各地区企业省域间的市场专业化分工,而非单独地嵌入GVC市场,利用集聚效应推动产业全面升级,打破国内市场循环的技术壁垒。