检索结果-南通市图书馆

Integral sliding mode control of time-delay systems with mismatching uncertainties

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Engineering and Electronics 2010年第2期21卷 273-280页

作者： fu Zhao Yu Liu Xiuming yao Baoku Su Space Control and Inertial Technology Research Center Harbin Institute of Technology Harbin 150001 R R. China

A linear matrix inequality （LMI）-based sliding surface design method for integral sliding mode control of uncertain time- delay systems with mismatching uncertainties is proposed. The uncertain time-delay system under consideration may have mis- matching norm bounded uncertainties in the state matrix as well as the input matrix, A sufficient condition for the existence of a sliding surface is given to guarantee asymptotic stability of the full order slJdJng mode dynamics. An LMI characterization of the slid- ing surface is given, together with an integral sliding mode control law guaranteeing the existence of a sliding mode from the initial time. Finally, a simulation is given to show the effectiveness of the proposed method.

关键词： linear matrix inequality integral sliding mode control uncertain time-delay systems mismatching uncertainties.

High order symplectic conservative perturbation method for time-varying Hamiltonian system

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Sinica 2012年第3期28卷 885-890页

作者： Ming-Hui fu ke-Lang Lu Lin-Hua Lan Department of Applied Mechanics and Engineering Sun Yat-sen University510275 GuangzhouChina

This paper presents a high order symplectic con- servative perturbation method for linear time-varying Hamil- tonian system. Firstly, the dynamic equation of Hamilto- nian system is gradually changed into a high order pertur- bation equation, which is solved approximately by resolv- ing the Hamiltonian coefficient matrix into a ＂major compo- nent＂ and a ＂high order small quantity＂ and using perturba- tion transformation technique, then the solution to the orig- inal equation of Hamiltonian system is determined through a series of inverse transform. Because the transfer matrix determined by the method in this paper is the product of a series of exponential matrixes, the transfer matrix is a sym- plectic matrix; furthermore, the exponential matrices can be calculated accurately by the precise time integration method, so the method presented in this paper has fine accuracy, ef- ficiency and stability. The examples show that the proposed method can also give good results even though a large time step is selected, and with the increase of the perturbation or- der, the perturbation solutions tend to exact solutions rapidly.

关键词： Time-varying Hamiltonian system High ordermultiplicative perturbation Symplectic conservation expo-nential matrix Precise time integration method

A novel two-stage Dissolved Gas Analysis fault diagnosis system based semi-supervised learning

在线全文

学校读者我要写书评

暂无评论

High Voltage 2022年第4期7卷 676-691页

作者： Xuemin Tan Chao Guo ke Wang fu Wan College of Control Engineering Chengdu University of Information TechnologyChengduChina State Grid Chengdu Power Supply Company ChengduChina China Electric Power Research Institute BeijingChina State key Laboratory of Power Transmission Equipment and System Security and New Technology Chongqing UniversityChongqingChina

Dissolved Gas Analysis(DGA)is an important method for oil-immersed transformer fault ***,collecting labelled DGA data is difficult because the determi-nation of the transformer fault is time-consuming and expensive in the transformer substation,but DGA data without labels is easier to ***,the paper pro-posed a semi-supervised two-stage diagnostic system based DGA by using less labelled *** two-stage system includes a novel semi-supervised feature selection based Genetic Algorithm(GA)and Support Vector Machine(SVM)model(SSL-FS-GASVM)for selecting optimal features and a novel semi-supervised transformer fault diagnosis model based improved Artificial Fish Swarm Algorithm(AFSA)and SVM(SSL-IAFSA-SVM)for optimising the SVM ***,the performances of SSL-FS-GASVM and SSL-IAFSA-SVM models are tested and compared with traditional supervised diagnostic models combined with other optimisation methods,*** results show that the proposed two-stage system works in optimising features and parameters and has strong robustness in solving small sample classification problems.

关键词： fault diagnosis system

Impact of Impeller Stagger Angles on Pressure Fluctuation for a Double-Suction Centrifugal Pump

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2018年第1期31卷 198-211页

作者： Da-Chun fu fu-Jun Wang Pei-Jian Zhou Ruo-fu Xiao Zhi-Feng yao College of Water Resources and Civil Engineering China Agricultural University Beijing Engineering Research Center of Safety and Energy Saving Technology for Water Supply Network System China Agricultural University College of Mechanical Engineering Zhejiang University of Technology

Pressure fluctuation may cause high amplitude of vibration of double-suction centrifugal pumps, but the impact of impeller stagger angles is still not well understood. In this paper, pressure fluctuation experiments are carried out for five impeller configurations with different stagger angles by using the same test rig system. Results show that the stagger angles exert negligible effects on the characteristics of head and efficiency. The distributions of pressure fluctuations are relatively uniform along the suction chamber wall, and the maximum pressure fluctuation amplitude is reached near the suction inlet tongue region. The pressure fluctuation characteristics are affected largely by impeller rotation, whose dominant frequencies include impeller rotation frequency and its harmonic frequencies, and half blade passage frequency. The stagger angle exerts a small effect on the pressure fluctuations in the suction chamber while a great effect on the pressure fluctuation in volute casing, especially on the aspect of decreasing the amplitude on blade passage frequency. Among the tested cases, the distribution of pressure fluctuations in the volute becomes more uniform than the other impeller configurations and the level of pressure fluctuation may be reduced by up to 50% when the impeller stagger angle is close to 24° or 360°.The impeller structure pattern needs to be taken into consideration during the design period, and the halfway staggered impeller is strongly recommended.

关键词： Double-suction centrifugal pump Impeller stagger angle Pressure fluctuation Frequency spectra analysis

Preparation of transparent TiO_2 nanocrystalline film for UV sensor

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 2006年第14期51卷 1657-1661页

作者： fu yao CAO Wanghe Optoelectronic Technology Institute Dalian Maritime University Dalian116026 China

nanocrystalline TiO_2 电影电极被大音阶的第五音胶化方法在不同锻烧的温度准备，它有不同电影厚度，一致透明性，以及光电的高度和机械稳定性的特征。光电的大小证明那锻烧的温度和电影厚度能显著地影响电极的光电的性质。在 450 deg... 详细信息

nanocrystalline TiO_2 电影电极被大音阶的第五音胶化方法在不同锻烧的温度准备，它有不同电影厚度，一致透明性，以及光电的高度和机械稳定性的特征。光电的大小证明那锻烧的温度和电影厚度能显著地影响电极的光电的性质。在 450 deg C 锻烧的电影是有 highcrystallinity 和强壮的光电的活动的锐钛矿阶段，并且显示出最大的光电流。当温度比 450 deg C 低时，因为很多缺点，这部电影在这部电影有更弱的结晶度，并且这不为 pho-togenerated 搬运人的运输是有利的。并且在比 450 deg C 高的温度，电极的光电流被减少在这部电影的到期的 toanatase 金红石阶段转变。电影厚度的增加对紫外光的改进有利(紫外) 吸收总计，它将改进这部电影的光电的活动。但是，过多的厚度将在电极在减小增加 theelectron 洞对，和结果的再结合率“ s photoelectric 活动。另外，在电极生产的光电流的反应敏感和稳定性与偏爱潜力有关。在 0.4 V 的一个潜力，电极显示出 30.8 亩 Aand 的浸透的光电流 ~ 的一反应时间 1 s，建议准备 TiO_2 拍摄电极能被用于做紫外传感器。

关键词：无机非金属材料功能材料纳米Ti02薄膜远红外传感器制备

Robust H_∞ filtering for discrete-time systems with Markovian switching and time-delays

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Engineering and Electronics 2009年第5期20卷 1072-1080页

作者： yao Xiuming Zhao fu Ling Mingxiang Wang Changhong Space Control and Inertia Technology Research Center Harbin Inst. of Technology Harbin 150001 P. R. China School of Science and Engineering North China Electric Power Univ. Beijing 102206 P. R. China

The robust H∞ filtering problem for uncertain discrete-time Markovian jump linear systems with mode- dependent time-delays is investigated. Attention is focused on designing a Markovian jump linear filter that ensures robust stochastic stability while achieving a prescribed H∞ performance level of the resulting filtering error system, for all admissible uncertainties. The key features of the approach include the introduction of a new type of stochastic Lyapunov functional and some free weighting matrix variables. Sufficient conditions for the solvability of this problem are obtained in terms of a set of linear matrix inequalities. Numerical examples are provided to demonstrate the reduced conservatism of the proposed approach.

关键词： discrete-time Markovian jump linear system robust H∞ filtering mode-dependent delay linear matrix inequality.

Optical and electrical properties of InGaZnON thin films

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2020年第1期29卷 475-481页

作者： Jian ke yao Fan Ye Ping Fan Shenzhen key Laboratory of Advanced Thin Films and Applications College of Physics and EnergyShenzhen UniversityShenzhen 518060China

The substrate temperature(Ts)and N2 partial pressure(PN2)dependent optical and electrical properties of sputtered InGaZnON thin films are *** the increased Ts and PN2,the thin film becomes more crystallized and *** Hall mobility,free carrier concentration(Ne),and electrical conductivity increase with the lowered interfacial potential barrier during crystal *** photoluminescence(PL)intensity decreases with the increased *** band gap(Eg)narrows and the linear refractive index(n1)increases with the increasing concentration of N in the thin *** Stokes shift between the PL peak and absorption edge decreases with *** n1,dispersion energy,average oscillator wavelength,and oscillator length strength all increase with *** single oscillator energy decreases with *** nonlinear refractive index and third order optical susceptibility increase with *** Seebeck coefficient,electron effective mass,mean free path,scattering time,and plasma energy are all Ne dependent.

关键词： InGaZnON thin films linear and nonlinear optical properties Seebeck coefficient electron effective mass

Recent progress on multifunctional electromagnetic interference shielding polymer composites

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2023年第3期134卷 106-131页

作者： ke Tian Danrong Hu Quan Wei Qiang fu Hua Deng College of Polymer Science and Engineering State Key Laboratory of Polymer Materials EngineeringSichuan UniversityChengdu 610065China Rehabilitation Medicine Center and Institute of Rehabilitation Medicine Key Laboratory of Rehabilitation Medicine in Sichuan ProvinceWest China HospitalSichuan UniversityChengdu 610041China

The explosive development of electronic devices and wireless communication technology gives rise to the issue of electromagnetic pollution,known as electromagnetic interference(EMI).The accumulation of undesirable electromagnetic radiation in space disturbs the normal function of unshielded electronic appliances and poses seriously threat to human ***,the development of EMI shielding materials have emerged to solve the grim *** the complex application contexts,EMI shielding materials have evolved from traditional single-function to multi-functions to meet the ever-increasing application requirements in recent few *** paper provides detailed insight into the current re-search status and future challenges in the advancement of polymer-based EMI shielding materials with various ***,the basic theory of EMI shielding,factors influencing results and the dominating characterization technologies for EMI shielding properties are ***,the comprehensive descriptions of the seven types of multifunctional EMI shields are provided with respect to their structures,fabrication methods and specific ***,the corresponding critical scientific and technical issues are *** on our comprehensive analysis,the main challenges in the development of multifunctional EMI shielding materials are *** review aims to provide some guidance and inspire more efforts toward functional EMI shielding material research to satisfy the growing requirements for next-generation electronic systems.

关键词： Polymer-based composites Electromagnetic interference shielding Multiple losses Multifunctionality

Successful treatment of encrusted cystitis:A case report and review of literature

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Clinical Cases 2020年第18期8卷 4234-4244页

作者： Jin-Gao fu ke-Ji Xie Department of Urology Jiangmen Central HospitalAffiliated Jiangmen Hospital of Sun Yat-Sen UniversityJiangmen 529000Guangdong ProvinceChina Department of Urology Guangzhou First People’s HospitalGuangzhou 510180Guangdong ProvinceChina

BACKGROUND Encrusted cystitis(EC)is a chronic inflammation of the bladder associated with mucosal *** diagnosis and optimal treatment are not well ***,we report a case of EC successfully treated with com-bination *** SUMMARY A 27-year-old man presented with frequency,urgency,dysuria,gross hematuria and suprapubic pain for 2 *** was diagnosed with EC based on characteristic calcifications of the bladder wall(most of them were struvite),cystoscopy and histopathological *** was cured after combined therapy of elimination of encrustations,bladder instillation of hyaluronic acid and injection of botulinum-A neurotoxin into bladder submucosal *** Bladder instillation of hyaluronic acid and injection of botulinum-A neurotoxin into the bladder submucosal tissue can be used for treatment of EC.

关键词： Cystitis Encrusted cystitis Incrusted cystitis Hyaluronic acid Case report Botulinum-A neurotoxin Botulinum toxin