检索结果-南通市图书馆

Mass-spring model for elastic wave propagation in multilayered van der Waals metamaterials

在线全文

学校读者我要写书评

暂无评论

Applied Mathematics and Mechanics(English Edition) 2024年第7期45卷 1107-1118页

作者： yabin JING Lifeng WANG Yuqiang gao State Key Laboratory of Mechanics and Control for Aerospace Structures Nanjing University of Aeronautics and Astronautics

Multilayered van der Waals（vdW） materials have attracted increasing interest because of the manipulability of their superior optical, electrical, thermal, and mechanical properties. A mass-spring model（MSM） for elastic wave propagation in multilayered vdW metamaterials is reported in this paper. Molecular dynamics（MD）simulations are adopted to simulate the propagation of elastic waves in multilayered vdW metamaterials. The results show that the graphene/MoS2metamaterials have an elastic wave bandgap in the terahertz range. The MSM for the multilayered vdW metamaterials is proposed, and the numerical simulation results show that this model can well describe the dispersion and transmission characteristics of the multilayered vdW metamaterials. The MSM can predict elastic wave transmission characteristics in multilayered vdW metamaterials stacked with different two-dimensional（2D） materials. The results presented in this paper offer theoretical help for the vibration reduction of multilayered vdW semiconductors.

关键词： multilayered van der Waals (vdW) metamaterial molecular dynamics (MD) mass-spring model (MSM) dispersion relation transmission characteristic O328 74H45

Event-based sliding mode control under denial-of-service attacks

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science China(Information Sciences) 2022年第6期65卷 125-141页

作者： Yingxin TIAN Xiang LI Bo DONG yabin gao Ligang WU Department of Control Science and Engineering Harbin Institute of Technology School of Software Harbin Institute of Technology

This paper deals with the problem of estimator-based sliding mode control against denial-of-service(DoS) attacks and discrete events via a time-delay approach. A networked system is considered an uncertain dynamical system with matched and mismatched perturbations and exogenous disturbance in the network environment. A network-resource-aware event-triggering mechanism is designed with aperiodically releasing system measurements. Furthermore, to describe the DoS attack duration and inter-event time, a time-delay modeling approach considers the DOS attack duration and inter-event time as a “time delay” of the measurements between the sensor and controller over the network is proposed. Consequently, an intervaltime-delay system with uncertainties is formulated. A state-observer-based sliding mode controller, by which the ideal sliding mode can be achieved, is proposed against the DoS attacks. The resulting sliding motion is proved to be robust and stable with an Lgain performance. Finally, the effectiveness and applicability of the present sliding mode control are validated in a simulated pendulum system.

关键词： sliding mode control time delay uncertain system state observer event trigger

Integral sliding mode control design for nonlinear stochastic systems under imperfect quantization

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science China(Information Sciences) 2017年第12期60卷 71-81页

作者： yabin gao Wensheng LUO Jianxing LIU Ligang WU Research Institute of Intelligent Control and Systems Harbin Institute of Technology

This paper presents a sliding mode control(SMC) scheme via output-feedback approach for It?o stochastic systems under a quantization mechanism. The quantization process is formulated with the imperfection that random packet loss occurs at the logarithmic quantizer. A Luenberger observer is designed, based on the packet loss rate and the imperfect quantized measurement. A novel SMC law is synthesized by utilization of an integral sliding surface. The stochastic stability of the resulting closed-loop system is analyzed in terms of Lyapunov stability, and a set of solvable matrix inequalities are established for practical application requirements. Finally, a simulation example is employed for the illustration of the effectiveness of the presented control scheme.

关键词： stochastic systems quantized control sliding mode control observer design packet loss

基于系统动力学的村镇基础设施安全韧性仿真研究

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

灾害学 2024年第2期39卷 34-41页

作者：田卫胡澳香马睿浩高明哲陈雅斌西安建筑科技大学土木工程学院陕西西安710055 西安建筑科大工程技术有限公司陕西西安710055 西咸新区住房和城乡建设局陕西西安712000

与城市相比,村镇在基础设施建设水平和抵御灾害的能力等方面都较低。厘清灾害风险与村镇基础设施安全韧性的关系,并评估村镇基础设施应对灾害的能力,有利于村镇基础设施的规划建设。采用系统动力学方法建立村镇基础设施安全韧性仿真模型... 详细信息

与城市相比,村镇在基础设施建设水平和抵御灾害的能力等方面都较低。厘清灾害风险与村镇基础设施安全韧性的关系,并评估村镇基础设施应对灾害的能力,有利于村镇基础设施的规划建设。采用系统动力学方法建立村镇基础设施安全韧性仿真模型,在确定模型变量权重的基础上,对村镇基础设施安全韧性进行模拟仿真。以西安市西咸新区大王街道为例,设定了现状延续型、经济发展型、政府干预型和安全韧性建设型4种发展情景,模拟不同情景下2019—2030年大王街道基础设施安全韧性的动态变化。结果表明:预计到2030年,政府干预型方案中基础设施安全韧性水平可达到0.779,是上述4种发展情景中基础设施安全韧性水平最高的,建议大王街道在现有规划的基础上可以考虑政府干预的发展规划进行调整完善。研究结果可为其他村镇规划建设提供理论依据和有效方法。

关键词：村镇基础设施安全韧性系统动力学仿真模拟

在线全文

学校读者我要写书评

暂无评论

厨余垃圾中高温高效厌氧产沼中试研究

环境卫生工程 2024年第2期32卷 39-45页

作者：田启欢高彦达宫亚斌杜睿王立伦姚建刚杭州能源环境工程有限公司浙江杭州311106 维尔利环保科技集团股份有限公司江苏常州213125

针对厨余垃圾资源化和能源化过程中存在的问题,通过中温(38℃)和中高温(44℃)连续厌氧发酵试验,分析不同温度发酵体系的产气特性、过程参数、微生物菌落结构及组成情况。结果表明:在相同进料负荷条件下,相比中温试验组,中高温试验组具... 详细信息

针对厨余垃圾资源化和能源化过程中存在的问题,通过中温(38℃)和中高温(44℃)连续厌氧发酵试验,分析不同温度发酵体系的产气特性、过程参数、微生物菌落结构及组成情况。结果表明:在相同进料负荷条件下,相比中温试验组,中高温试验组具有较高的容积产气率、甲烷产气率等产气特性,且具有较高的底物VS降解率。中高温发酵系统在VFAs、氨氮、总碱度、pH等过程参数分析中更稳定,具有一定的抵抗负荷冲击能力。高通量微生物群落多样性探究中,中高温发酵表现为细菌中菌种相对丰富度多元化,古细菌中产甲烷菌属优势明显,表明中高温厌氧发酵系统中微生物菌落间相互促进和配合,促进了厌氧发酵过程中各物料参数的稳定有序转化,保证了厌氧系统的稳定高效运行。

关键词：厨余垃圾厌氧发酵中高温中温微生物群落

同方期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

王自敏教授分期分型辨治IgA肾病经验

浙江中医药大学学报 2024年第5期48卷 572-575页

作者：范坤鹏邢海燕高亚斌杨青芸王自敏河南中医药大学郑州450000 河南中医药大学第一附属医院

[目的]总结王自敏教授分期分型辨治IgA肾病的经验。[方法]通过跟师学习,收集病案,总结探讨王老治疗IgA肾病的经验,并附医案一则。[结果]王老认为,IgA肾病属本虚标实、虚实夹杂之病,病位主要在肾,与肝、脾、肺密切相关,病因分为内因和外... 详细信息

[目的]总结王自敏教授分期分型辨治IgA肾病的经验。[方法]通过跟师学习,收集病案,总结探讨王老治疗IgA肾病的经验,并附医案一则。[结果]王老认为,IgA肾病属本虚标实、虚实夹杂之病,病位主要在肾,与肝、脾、肺密切相关,病因分为内因和外因,两者合而为病,并认为本病核心病机为“湿、热、瘀、虚”,将本病分为急性发作期和慢性持续期,急性发作期分为风热袭肺型、心火亢盛型、湿浊犯脾型和下焦湿热型,慢性持续期分为阴虚火旺型、气阴两虚型、脾肾亏虚型以及瘀毒阻络型。王老针对不同证型,分别给予银翘散、导赤散、小蓟饮子、知柏地黄丸合二至丸、黄芪地黄汤、六君子汤合右归丸、自拟黄槐温胆汤合血府逐瘀汤等加减治疗。王老指出,本病治疗以扶正祛邪、攻补兼施为治则,主张中西医结合,并善用药对精准治疗。所附医案首诊时辨为阴虚火旺型,治以滋阴降火、清热凉血,予知柏地黄丸合二至丸加减,后随证加减,疗效甚佳。[结论]王老分期分型治疗IgA肾病经验丰富,提出本病核心病机为“湿、热、瘀、虚”,对治疗本病有较高的指导意义。

关键词： IgA肾病中西医结合分期分型药对病机名医经验

层状结构BiOBr的形成机理及其光催化降解抗生素性能

在线全文

学校读者我要写书评

暂无评论

工业催化 2024年第7期32卷 30-36页

作者：徐甜甜靳亚斌高占尧郑煜鑫周亮西安航空学院能源与建筑学院陕西西安710077 西安工程大学环境与化学工程学院陕西西安710048

通过水热合成法片层结构溴氧化铋(BiOBr)颗粒,探究其形成机理,并在氙灯光照下以喹诺酮类抗生素诺氟沙星(NOR)为降解底物,考察BiOBr形貌结构变化对光催化性能的影响。X射线衍射(XRD)和扫描电子显微镜(SEM)分析确认BiOBr制备成功。结果表... 详细信息

通过水热合成法片层结构溴氧化铋(BiOBr)颗粒,探究其形成机理,并在氙灯光照下以喹诺酮类抗生素诺氟沙星(NOR)为降解底物,考察BiOBr形貌结构变化对光催化性能的影响。X射线衍射(XRD)和扫描电子显微镜(SEM)分析确认BiOBr制备成功。结果表明,水热合成条件下制备的BiOBr为片层结构,随反应溶液pH值的增加,颗粒尺寸逐渐变小,且分散性越来越差,吸收带边发生蓝移,禁带宽度变大。分析水溶剂环境下片层BiOBr的形貌变化生长机理,当pH=1时,BiOBr形貌为均匀的片状结构,宽度为(3~5)μm,禁带宽度为2.93 eV,表现出最佳的光催化活性,光催化反应60 min后,NOR的降解率达到87.2%,最高降解速率常数为3.31×10^(-2)min^(-1)。

关键词：催化化学溴氧化铋层状结构生长机理光催化动力学模型

基于Ventsim的王家塔煤矿通风系统优化研究

在线全文

学校读者我要写书评

暂无评论

煤炭技术 2024年第2期43卷 145-149页

作者：王兵建刘煜成高运增王亚斌河南理工大学能源科学与工程学院河南焦作454003 北京天地华泰矿业管理股份有限公司北京100013

针对王家塔煤矿存在的多煤层、多盘区、供风线路长和通风阻力分布不协调等特点,尤其是随着4^(#)煤开拓和3^(#)煤3盘区的准备,通风系统的不合理性更加凸显。在获取可靠通风基础参数的基础上,利用Ventsim建立王家塔煤矿全矿井三维可视化... 详细信息

针对王家塔煤矿存在的多煤层、多盘区、供风线路长和通风阻力分布不协调等特点,尤其是随着4^(#)煤开拓和3^(#)煤3盘区的准备,通风系统的不合理性更加凸显。在获取可靠通风基础参数的基础上,利用Ventsim建立王家塔煤矿全矿井三维可视化模型并完成仿真模拟,按照调风操作可行、简单、可靠的原则,提出优化调整方案并模拟分析了调风效果。调风实践表明,优化后的通风系统稳定性增强,通风总阻力降低,阻力分布趋于合理,既实现了企业通风的节能降耗和成本开支,又全面提升了矿井的通风管理水平及决策能力,对矿井通风管理有较好的指导作用。

关键词：矿井通风阻力分布通风网络通风系统优化节能降耗

Resonance analysis of single DOF parameter-varying system of magnetic-liquid double suspension bearing

在线全文

学校读者我要写书评

暂无评论

High Technology Letters 2022年第1期28卷 72-79页

作者：赵建华 ZHAO yabin ZHANG Xuze WANG Jin WANG Ziqi gao Dianrong DU Guojun Fluid Power Transmission and Control Laboratory Yanshan UniversityQinhuangdao 066004P.R.China No.7 Branch Company Qinhuangdao Port Co.LtdQinhuangdao 066002P.R.China College of Civil Engineering and Mechanics Yanshan UniversityQinhuangdao 066004P.R.China

Magnetic-liquid double suspension bearing(MLDSB)is mainly supported by electromagnetic suspension and supplemented by hydrostatic supporting.Its bearing capacity and stiffness can be greatly improved,and then it is suitable for the occasions of medium speed,heavy load.When the bearing system is excited by periodic force,the flow q and current i regulated by the double-closed-loop control mechanism change periodically.Then the risk of parametric resonance in MLDSB is greatly aggravated by the change of the parameter system,which seriously affects its operation stabil-ity and reliability.Therefore,this paper intends to study the resonance characteristics of the parame-ter system of MLDSB.Firstly,Marshall-Duffing equation of the parametric system is established by taking the flow q and the current i as variables respectively.Then,by using the asymptotic method,the occurrence condition and variation rule of the principal,1/2 Harmonic and 1/3 Harmonic para-metric resonance are solved.The results show that only the 1/2 Harmonic resonance of the flow q parameter varying system occurs accompanied by the resonance condition of high frequency.The principal,1/2 Harmonic and 1/3 Harmonic parametric resonance of the current i occur accompanied by the resonance condition of high frequency.And the 1/2 Harmonic resonance of the current i oc-curs accompanied by the non-single value bifurcation and dynamic bifurcation.The paper can pro-vide theoretical reference for the parameter design and stable operation of MLDSB.

关键词： magnetic-liquid double suspension bearing(MLDSB) resonance analysis flow parameter varying system current parameter varying system