Acoustic topological phase transition induced by band inversion of high-order compound modes and robust pseudospin-dependent transport

A simple two-dimensional phononic crystal hosting topologically protected edge states is proposed to emulate the quantum spin Hall effect in electronic systems, whose phononic topological phase can be reconfigured through the rotation of scatters. In particular, the band inversion occurs between two pairs of high-order compound states, resulting in topological phase transition from trivial to nontrivial over a relatively broad high-frequency range. This is further evidenced by an effective Hamiltonian derived by the k·p perturbation theory. The phononic topology is related to a pseudo-timereversal symmetry constructed by the point group symmetry of two doubly degenerate eigenstates. Numerical simulations unambiguously demonstrate robust helical edge states whose pseudospin indices are locked to the propagation direction along the interface between topologically trivial and nontrivial phononic crystals. Our designed phononic systems provide potential applications in robust acoustic signal transport along any desired path over a high-frequency range.

Cavity-Mode Properties of Semiconductor Lasers Operating in Strong-Feedback Regime

This paper investigates the modal properties of semiconductor lasers operating in the strong-feedback regime. Analytical expressions are developed based on an iterative travelling-wave model, which enable a complete and quantitative description of a compound cavity mode in its steady state. Additional information is provided about the physical inside into a compound laser system, such as a bifurcation diagram of the compound cavity modes for full variation range （from 0 to 1） of the external reflection coefficient and a more general shape for the diagram of photon density versus mode phase - this latter will reduce to the classical ＂ellipse＂ in the weak-feedback regime. It is shown that in the strong-feedback regime, a feedback laser is characterized by a small mode number and a high density of photons. This behavior confirms previous experimental observations, showing that beyond the coherence-collapse regime, the compound laser system could be re-stabilized, and that as a result power-enhanced low-noise stable laser operation with quasi-uniform pulsation is possible with external-mirror reflectivity close to 1. Moreover, it is also shown that for a compound system operating in the strong-feedback regime, an anti-reflection treatment of a laser can significantly reduce its current threshold, and that in the absence of this treatment excitation of a minimum-linewidth mode with higher output power would be possible inside such a system. Finally, it is shown that in the weak-feedback regime except for a phase shift the iterative travelling-wave model will reduce to the Lang-Kobayashi model in cases where the product of the feedback rate and the internal round-trip time is much less than unity （that would mean in situations of as-cleaved lasers）.

Anomalous low-temperature heat capacity in antiperovskite compounds

The low-temperature heat capacities are studied for antiperovskite compounds AX M_3（A = Al, Ga, Cu, Ag, Sn, X = C,N, M = Mn, Fe, Co）. A large peak in（C- γ T）/T^3 versus T is observed for each of a total of 18 compounds investigated,indicating an existence of low-energy phonon mode unexpected by Debye T^3 law. Such a peak is insensitive to the external magnetic field up to 80 k Oe（1 Oe = 79.5775 A·m-1）. For compounds with smaller lattice constant, the peak shifts towards higher temperatures with a reduction of peak height. This abnormal peak in（C- γ T）/T^3 versus T of antiperovskite compound may result from the strongly dispersive acoustic branch due to the heavier A atoms and the optical-like mode from the dynamic rotation of X M_6 octahedron. Such a low-energy phonon mode may not contribute negatively to the normal thermal expansion in AX M_3 compounds, while it is usually concomitant with negative thermal expansion in open-structure material（e.g., ZrW_2O_8, Sc F_3）.

Synthesis, Structure and Decarboxylative Behavior of a Nitro-coordinated Potassium Compound

A novel nitro-coordinated potassium compound [K(Htdc)(H_2O)]_n(tdc = 3-nitro-thiophene-2,5-dicarboxylate), has been synthesized and characterized. The complex with a two-dimensional(2D) layer structure contains an infinite K-O ladder-shaped chain, which is connected through carboxyl and unusual nitro-coordination of Htdc– anion. Then the 2D layers are further extended by intermolecular hydrogen-bonding to form a three-dimensional(3D) supramoleculalr network. Variable temperature powder X-ray diffractions, thermogravimetric analysis and nuclear magnetic resonance studies exhibit that the compound has a thermal-induced decarboxylative behavior.

新文科背景下复合型人才培养实践模式研究

新文科建设背景下,各高校在跨学科、跨专业的复合型人才培养方面积极进行改革和创新尝试,形成了诸多值得借鉴的典型模式。通过对全国数十所高校新文科建设中复合型人才培养情况进行总结和分析,研究将现有人才培养模式归纳为双学位和联合学位模式、微专业模式、文科实验室模式、书院模式。这四种典型模式各有优势,用新视角、新范式、新方法带动了传统文科转型升级。未来,各高校应继续探索建立以立德树人为目标、以优势学科为核心、以学科交叉为抓手、以名家大师为引领的复合型文科人才培养体系。

Robust controller design for compound control missile with fixed bounded convergence time

A robust controller for bank to turn(BTT) missiles with aerodynamic fins and reaction jet control system(RCS) is developed based on nonlinear control dynamic models comprising couplings and aerodynamic uncertainties. The fixed time convergence theory is incorporated with the sliding mode control technique to ensure that the system tracks the desired command within uniform bounded time under different initial conditions. Unlike previous terminal sliding mode approaches, the bound of settling time is independent of the initial state, which means performance metrics like convergence rate can be predicted beforehand. To reduce the burden of control design in terms of robustness, extended state observer(ESO) is introduced for uncertainty estimation with the output substituted into the controller as feedforward compensation. Cascade control structure is employed with the proposed control law and therein the compound control signal is obtained.Afterwards, control inputs for two kinds of actuators are allocated on the basis of their inherent characteristics. Finally, a number of simulations are carried out and demonstrate the effectiveness of the designed controller.

数字经济时代复合型人才培养模式创新研究——以经济与贸易类专业为例

数字经济快速发展引发了就业深刻变革,社会对经济与贸易人才需求发生了新变化,迫切需要具有数字素养和基本数字技能的“大数据+信息技术+贸易”中高端复合型贸易人才。我国经济与贸易类专业复合型人才培养模式呈现多样化,部分高校复合型人才培养形成自身特色。数字经济时代经济与贸易类专业复合型人才培养,需要以“数字技术+贸易实务”为核心进行跨专业融合,构建“面向全流程、学科交叉融合、多元主体协同”的复合型贸易人才培养新模式,以全新理念设计人才培养方案和课程体系,加强数字化复合型师资队伍建设,加快建设多元化网络教学平台。建设培养复合型人才的多元化教学平台。

新时代复合型立法人才培养的模式创新与实践

为贯彻落实习近平总书记关于加强法治队伍特别是立法队伍建设的讲话精神,适应新时代法学教育和法学理论研究的新需求,围绕“统筹推进国内法治和涉外法治”的基本要求,厦门大学立法团队探索建设了新时代复合型立法人才的培养模式。针对立法人才培养过程中存在的“学科体系不够完善”“理论实践融合有限”“人才培养口径过窄”“师资结构较为单一”等问题,厦门大学立法教学团队在培养理念、模式、方案和机制等方面守正创新,形成了“一个目标、二元互动、三位一体、四维协同”的复合型立法人才培养模式,在立法课程体系建设、实战化教学模式创新、国际化办学持续推进等方面积累了丰富经验,在理念、模式、实践和机制等方面具备创新性和可复制推广性,为培养复合型立法人才、推进立法职业共同体建设作出了重要贡献。

双模功率分流式混合动力汽车传动系统设计

针对双模功率分流式混合动力汽车传动系统的构型,首先,对比分析了单、双模式混合动力系统结构特征及应用范围;然后,结合复合分配式特点,选定3种复合分配式四结点杆模型,通过逆向拆分得到所有可行的复合分配式构型,并根据杆长度和特征参数约束条件,确定构型方案;最后,在此基础上,参考某款车型参数,通过分析输入分配模式、模式切换点和机械点特性确定第3排行星排和离合器位置及结构参数,设计出传动系统构型,为研究双模功率分流式混合动力汽车传动系统提供理论依据。

夏大豆玉米不同带状复合种植模式及不同生育时期喷施“海藻博士”对玉米产量的影响

玉米-大豆带状复合种植技术具有保证玉米产量的前提下,提高大豆产量的作用,其田间配置直接影响玉米生长发育及产量。通过比较不同玉米大豆带状复合种植模式对玉米产量的影响,筛选出适宜江苏省的种植模式;同时研究了不同玉米生育期喷施“海藻博士”对玉米产量等相关性状的影响。结果表明,采用4//4玉米“品字型”种植模式结合在三叶期、拔节期、抽穗扬花期喷施3 750 g/hm^(2)海藻博士水剂,对玉米产量相关性状和生物量分配效果最佳,产量可以达到14 087.2 kg/hm^(2),百粒重达到37.4 g。

新发展阶段“IKAQ”结构视域下新工科复合型人才的核心素养及培养探究

我国处于全面建设社会主义现代化国家、向第二个百年奋斗目标进军的新发展阶段。在新工科快速发展的教育改革形势下,该文根据当今对新工科复合型人才的需求,分析驱动人才发展的四个维度素养,对新工科复合型人才培养教育理论原理、特征需求、存在问题、模式方法及实践效果等进行研究,为探索新发展阶段下新工科复合型人才培养的核心素养和构建培养模式提供方法和途径。

VMD引导的轮对与轴承复合故障诊断方法

针对列车轮对轴承系统复合故障难以辨识与诊断问题,提出一种变分模态分解(variational mode decomposition,VMD)引导的多故障特征提取匹配方法.首先,为避免预定义模式数在运行过程中对先验知识依赖从而对诊断结果造成影响,对原始轴箱振动数据进行逐阶VMD分解,模式数为2~N;其次,对VMD分解获取的本征模态函数(VMD intrinsic mode functions,VIMF)进行相关峭度计算,提取相关峭度最大的VIMF;然后,将相关峭度最大的VIMF进行平方包络分析,提取故障特征频率;最后,将所提方法与快速峭度谱、相关峭度谱方法进行对比.仿真信号和试验数据分析表明:所提方法完全规避了VMD模型中关键参数K的选择问题,可以准确、有效地分别提取出轮对和轴承的故障特征;与快速谱峭度与相关谱峭度方法相比,获取的故障特征谐波分量在数量和信噪比上均具有明显优势.

“医学+人工智能”复合型创新人才培养模式探析

近年来,人工智能技术越来越广泛地应用于医疗行业,这既推动了精准医疗的发展,也对医学教育改革提出新的要求。自“新医科”理念提出以来,中国医学院校在“医学+人工智能”复合型创新人才培养方面进行了深入的探索与实践,在取得成绩的同时也暴露一些问题。文章从制定“医学+人工智能”教育顶层规划、探索多主体共同协作模式、构建“课程+项目+评价”创新型人才培养模式三个方面对医学院校人工智能教育提出对策建议,为医学教育与人工智能技术深度融合发展提供思路。

基于粒子群优化ACMD方法的滚动轴承复合故障分离方法

为了对强背景噪声干扰下的滚动轴承复合故障特征进行提取,课题组提出一种基于粒子群和自适应调频模式分解(adaptive chirp mode decomposition,ACMD)的滚动轴承复合故障分离的特征提取方法。首先,构建一个复合故障分解因子(compound fault decomposition factor,CFDF)用于评价复合故障特征提取效果;然后,将最大复合故障分解因子作为目标函数,利用粒子群寻优算法自适应搜索ACMD最优参数,进而实现信号模态分解;最后,对分解后的多模态分量进行平方包络谱分析,进而判断轴承的故障类型。仿真及试验结果表明:该方法能够实现强背景噪声干扰下的滚动轴承复合故障特征提取,分离出单一的故障信息。对比经典VMD方法,该方法具有更好的鲁棒性。

基于优化VMD-MCKD和谱峭度的滚动轴承复合故障诊断

针对滚动轴承振动信号中复合故障特征难以准确提取而导致故障诊断困难的问题,提出一种基于优化变分模态分解(VMD)和最大相关峭度解卷积(MCKD)结合快速谱峭度算法的滚动轴承复合故障诊断方法。利用改进麻雀搜索算法(ISSA)优化VMD和MCKD的参数,使用优化后的VMD对复合故障信号进行分解,并根据峭度准则筛选有效本征模态函数(IMF)进行信号重构,使用优化后的MCKD对重构信号进行解卷积与故障特征增强,并对解卷积信号进行包络谱分析提取故障特征频率。利用快速谱峭度算法对未提取出故障特征频率的解卷积信号进行处理,得到故障信息最丰富的频带参数并进行带通滤波处理。最后,对滤波后的信号进行包络谱分析,提取故障特征频率,从而实现故障诊断。仿真及实验结果表明:所提方法能有效分离复合故障并提取出故障特征频率,有效实现了复合故障诊断。

湖南省大豆玉米带状复合种植模式及病虫草害综合防控技术

大豆作为我国重要的粮油兼用作物,在国家粮食安全中占有重要地位。但是,我国大豆种植面积有限,单作产量较低,常年依赖进口。因此,我国提出了大豆玉米带状复合种植模式。近年来,湖南省大力发展大豆玉米带状复合种植,围绕种植技术的田间试验、集成应用和示范推广开展了深入研究。本文从品种选择、行比配置、播种、田间管理、收获等方面总结了湖南省大豆玉米带状复合种植技术,并总结了病虫草害综合防控技术,分析了种植技术环节存在的问题,以期为该种植模式的推广应用提供参考。

双泵分腔调控电液负载模拟系统复合滑模控制

针对阀控电液负载模拟系统中存在的能耗高、非线性摩擦和舵机运动干扰等问题,提出双泵控制电液负载模拟系统的方案,并且采用滑模控制以保证系统的鲁棒性。建立双泵分腔调控电液负载模拟系统的数学模型;在此基础上,针对单泵控系统动态特性差的问题,设计力-总压力复合控制策略,使其具有和阀控系统相似的动态特性;对于传统的滑模控制造成系统抖振而引起系统的跟踪效果不好的问题,提出一种基于模糊趋近律的等效滑模控制器,并对其稳定性进行了理论分析。最后,经过联合仿真,验证了所设计的控制策略和控制器具有可行性和有效性。结果表明:所提出的复合滑模控制电液负载模拟系统具有良好的跟踪效果,且能够显著地降低系统能耗。

新文科背景下地方本科院校“1+X”复合型音乐表演人才培养模式构建研究

“1+X”复合型音乐表演人才培养模式是适应当前区域经济社会发展对高素质复合型音乐表演人才的实际需求,以“新文科”建设理念为根本指导思想,强调跨学科融合发展,对地方本科院校音乐表演专业现有的课程体系、教学内容、教学方法、教学手段、培养制度、评价制度等进行改革创新,而构建的一套人才培养模式。这一人才培养模式强调对学生专业能力和素质的综合培养,要求学生不仅要精通本专业的知识和技能,还要学习掌握与本职工作密切相关的专业技术,以适应社会多方面的工作要求。

产业视角下新医科现代产业学院育人模式探讨

产业学院旨在培养大批产业需要的高素质应用型、复合型、创新型人才,为提高产业竞争力和汇聚发展新动能提供人才支持和智力支撑。产业视角的新医科产业学院的人才培养模式要大胆改革创新,探索教育链、创新链、产业链有效衔接机制,建立新型信息、人才、技术与物质资源共享机制,完善产教融合协同育人机制。南华大学现代生物医药产业学院积极抓住成为湖南省首批现代产业学院的契机,在人才培养、专业建设等育人模式的七个方面不断探索,为新医科现代产业学院的建设提供可复制、可推广的新模式。

新文科背景下工程管理复合型应用人才培养模式研究

新文科建设背景下,工程管理加快了复合型应用人才培养模式改革的步伐。基于新文科建设和工程管理专业培养模式相关文献研究,分析了工程管理复合型人才培养的必要性,思考了培养模式的弊端,明确了课程体系中课程融通交叉不足、教学效果不理想、教学资源不充足等问题短板。借鉴国内同类型地方高校培养经验,从课程体系、师资建设、资源保障等方面提出改进策略,为提高学校工程管理专业人才培养水平提供重要支撑,并为同类型高校工程管理专业建设和人才培养模式改革提供参考。