Two Time-Scale Feedback Stabilization of Linear Time-Varying Singularly Perturbed Systems

The stabilization of a class of singularly perturbed linear time-varying systems is considered through the separate stabilization of two lower dimensional subsystems in two different time-scales. A composite stabilizing controller is synthesized from the separate stabilizing controllers of the two subsystems, the mutually independent gains of which do not require knowledge of the small singular perturbation parameter.     

构建广州市科普基地认定和评估指标体系研究

通过对科普基地相关运营管理理论展开理论研究,对国内外科普基地管理的典型案例进行案例研究,总结科普基地运营管理的一般规律,在现行广州市科普基地认定、评估指标体系的基础上,对其进行设计、修改和完善。同时通过专家访谈并借鉴理论和实践经验,采用层次分析法对该指标体系进行权重赋值,构建广州市科普基地认定和评估指标体系,为提升广州科普基地运营管理能力提供有效依据。     

京津冀协同发展背景下的科技资源分布与共享现状分析

基于京津冀协同发展背景,对京津冀地区的科研投入、产出、相关科技资源分布、协同共享等情况进行调研,并揭示三地科技合作现状及面临的问题。研究结果表明：京津冀科研投入差距巨大,科研投入结构差异大;虽然三地科研产出差距大,但研发领域相似且各具特色,科研产出以当地特色产业为依托;京津冀三地科技合作比例偏低,但专利转让相对活跃。目前,京津冀科技合作与资源共享以“点对点”的形式为主,未来,深度的合作尚需政府引导、上层推进,形成以产业链为依托的科技合作形式。     

An Upper Bound for the Singular Parameter in a Stable,Singularly Perturbed System

This paper considers the problem of stability of a singularly perturbed system and of finding an upper bound for the parameter when the order of the system changes as a result of parameter perturbation. By means of the contraction mapping technique, conditions have been derived for determining explicitly the range of parameter perturbation such that both bounded-input-bounded-output and asymptotic stabilities are insured. In addition, bounds of the state and output of the singularly perturbed system can be found. Two examples are given to illustrate the application and significance of the results.     

科技成果转化为技术标准发展现状与典型路径

通过研究国内外科技成果转化为技术标准发展现状,以及我国科技成果转化为技术标准的典型经验和做法,以科技成果转化为技术标准的主体为视角,分析各主体在科技成果转化为技术标准方面的优势与不足,归纳提出大型企业、产业联盟、标准化专业机构和高新技术区域开展科技成果转化为技术标准的典型路径。此外,针对高校和中小型企业尚未形成科技成果转化为技术标准典型路径这一问题,找出影响因素,提出相应的意见建议。最后,结合我国实际情况,提出我国今后开展科技成果转化为技术标准工作的构想。     

创新激励政策对高新技术企业创新质量的作用效果评估

关注政府对高新技术企业实施激励政策时有关补贴对象的异质性问题和不同政策对各项创新产出的不同效果，基于2015—2018年科技部火炬中心对广东省高新技术企业的统计调查数据，运用多层线性模型评估税收优惠和财政补贴两类创新激励政策对不同企业规模、行业类型、高企类别的高新技术企业创新质量提升效果。结果表明：税收优惠和财政补贴政策对高新技术企业创新质量有显著提升作用，但对不同规模、行业、类别高新技术企业的科技成果转化能力、知识产权与技术标准、研发投入强度、财务能力、新产品收入等创新质量产出作用效果存在差异。其中，两类政策对企业科技成果转化能力的作用效果较强，对知识产权与技术标准、资产回报率的作用效果较弱；财政补贴对入库培育企业科技成果转化能力有负向作用；税收优惠对电子信息与服务业企业研发投入强度有负向作用。基于此，建议广东省通过继续实施财政补贴、高新技术企业入库培育等创新激励政策，关注中小微高新技术企业需求、促进大型高新技术企业做大做优，打造高新技术企业创新生态链等措施，推动高新技术企业创新质量提升。     

林业领域国家重点研发专项资金项目绩效评价体系构建初探

通过层次分析法和模糊综合评价相结合,建立林业领域国家重点研发专项绩效评价指标层次结构模型,根据最低层次各指标权重和指标值对考评对象作出综合评估,形成评价指标体系。在以上分析基础上,运用主成分分析法,提取关键的评价因子,制定合理的林业领域国家重点研发专项绩效评价方案。     

乡村振兴背景下基于扎根理论的农业科技人才胜任力模型构建研究

农业科技人才作为推进农业现代化的中坚力量,在乡村振兴战略实施中起到关键性作用。为厘清农业科技人才胜任特征内在构架,采用行为事件访谈法和扎根理论探索乡村振兴背景下农业科技人才必备胜任要素,充分构建新时代农业科技人才胜任力模型,包括专业知识、专业技能、身体素质、心理素质、道德品质、创新能力、风险管控和成就驱动等八大维度,以期为农业科技人才甄选、培训与开发及职业发展提供理论指导。     

德国量子计划对我国超前布局未来产业的启示

随着新一轮科技革命和产业变革的兴起,前瞻布局未来产业成为世界主要国家占据科技竞争制高点的重要举措。本文以德国量子计划为例,逐层分析德国关于量子计划的战略重点与关键性行动举措,在总结分析我国未来产业发展现状的基础上,结合国家战略定位和政策体系设定,从战略规划、专项资金支持、构建合作平台以及鼓励公众参与四个方面提出相应的对策建议。     

基于Sci2的国外经济学知识图谱研究

为发掘出国外经济学领域的研究热点,文章将文献计量学的方法引入经济学领域,借助Histcite对数据进行全面的统计分析,利用知识图谱工具Sci²构建共词网络,将国外经济学的发展情况以可视化的方式展示。文章首先阐述了数据来源的依据,并对知识图谱工具Histcite和Sci²做了简单的介绍;其次对数据概况进行全面的分析;最后,抽取高频关键词进行共词分析,通过共词网络,分析出3年来国外经济学领域的研究前沿。     

一类多时滞的向量差分方程的渐近稳定性（英文）

本文讨论了一类具有时滞的差分方程的渐近稳定性。利用矩阵性质和不等式技巧给出了该类方程渐近稳定的充要条件。     

Designing artificial ion channels with strict K+/Na+ selectivity toward next-generation electric-eel-mimetic ionic power generation

A biological potassium channel is> 1000 times more permeable to K⁺than to Na⁺ and exhibits a giant permeation rate of ～10⁸ ions/s.It is a great challenge to construct artificial potassium channels with such high sele ctivity and ion conduction rate.Herein,we unveil a long-overlo oked structural feature that underpins the ultra-high K⁺/Na⁺ selectivity.By carrying out massive molecular dynamics simulation for ion transport through carbonyl-...     

Transport Phenomena in Heterogeneous Media1

Classical work on transport in heterogeneous media is reviewed to show the broad interest in it as well as the specific need for a thorough treatment of a more comprehensive model. Such a model is presented and it consists of a random distribution of one or more dispersed phases in a continuous phase. Both the stab and spherical geometry are also considered. Both the transient and steady state transport solutions are developed for each of three different cases. The equivalent diffusivities are extracted from the steady state solutions. Applications are considered to illustrate the validity of the work. It is emphasized that the flux J_i for phase i can be complex as discussed elsewhere in the literature and all of this without any detraction from the exposition presented. It is also pointed out that this exposition is apparently the first to establish the connection between a realistic model, its transient solutions and its steady state solutions from which the equivalent diffusivities have been extracted. In the case of dead-end pores the results suggest application to experimental data to serve as a precision test for the presence and amount of dead-end pores. The advantages of testing under steady state conditions are discussed in detail. An appropriate diffusion cell design is referenced. The results can be useful in the research and design of barrier materials, catalysts, etc.     

An Age Dependent Epidemic Model*

The model presented here describes the spread of an infection in a population by keeping track of the chronological ages of the participants as well as their “class ages” (i.e. the length of time since entering their present state). The reasoning behind this model is similar to that used in the equation of age dependent population growth.     

高校促进原创性基础研究管理服务工作探讨—基于原创探索计划项目及北京大学视角

通过对科学基金原创项目2020—2021年度申请资助情况进行深入分析，并以北京大学获资助原创项目作为具体案例进行探讨后发现，项目资助对研究质量把关严格，对青年科技人才适当倾斜，鼓励学科交叉类基础研究。从科研管理服务的视角为高校促进原创性基础研究提出相关对策建议。     

新疆风电产业与政策发展现状及其关系研究——基于创新系统功能视角

研究采用创新系统功能分析方法,对新疆风电产业及政策现状进行系统分析。研究发现,在新疆风电产业政策目标、行为主体、政策强度发生变化时,风电产业内行为主体需根据政策变化,对产业创新资源流动、风电市场培育、企业能力提升等方面做出相应的调整,才能适应当前政策的发展方向。反之,新疆风电产业的发展具有一定的阶段性特征,政策的制定必须随产业的发展做出及时有效的调整,才能达到风电产业发展与政策之间形成良好的交互机制,从而推动新疆风电产业健康持续发展。     

Partial derivative properties of multivariable cascaded networks1

Some partial derivative properties of the impedance function of a resistively-terminated network which is a cascade of m lossless two-ports of variables p₁ to p_m dre established. Those cases where some of the lossless two-ports are lowpass or highpass ladder networks with all of their transmission zeros at the origin or at infinity are also examined. Necessary and sufficient conditions involving partial derivatives and under which an m-variable reactance or positive real function can be realized as the impedance function of a p_i-variable lowpass or highpass ladder network, with all of its transmission zeros at p_i = 0 or p_i = ∞, and terminated in a reactance or positive real impedance function in the other variables are derived.     

类锌W44+离子双电子复合速率系数的理论研究

利用全相对论组态相互作用理论方法,计算了类锌W44+离子从基态3s23p63d104s2经过双激发态(3s23p 63d104s2)-1nln'l'(n=4、5;n'=4～15)的双电子复合(DR)速率系数,通过对不同电子激发的DR速率系数的比较,得知4s电子激发的DR速率系数在低温时给出了主要贡献,而3d的贡献在高温时突出;分别分析了不同电子激发的DR速率系数随l'和n'的变化,由此给出了l'的截断值.     

一类SIR传染病离散模型的持久性与稳定性

本文探讨一类SIR传染病离散模型的持久性和全局稳定性。     

Stability and L2-gain analysis for switched neutral systems with mixed time-varying delays

This paper considers the stability and L₂-gain for a class of switched neutral systems with time-varying discrete and neutral delays. Some new delay-dependent sufficient conditions for exponential stability and weighted L₂-gain are developed for a class of switching signals with average dwell time. These conditions are formulated in terms of linear matrix inequalities (LMIs) and are derived by employing free weighting matrices method. As a special case of such switching signals, we can obtain exponential stability and normal L₂-gain under arbitrary switching signals. Finally, two numerical examples are given to illustrate the effectiveness of the theoretical results.