检索结果-南通市图书馆

Weak Fault Feature Extraction of the Rotating Machinery Using Flexible Analytic Wavelet Transform and Nonlinear Quantum Permutation Entropy

引用

Computers, Materials & Continua 2024年第6期79卷 4513-4531页

作者： lili bai Wenhui li He Ren Feng li TaoYan lirong Chen College of Aeronautics and Astronautics Taiyuan University of TechnologyTaiyuan030024China Commercial Aircraft Corporation of China Ltd.Shanghai200126China College of Physics and Electronic Engineering State Key Laboratory of Quantum Optics and Quantum Optics DevicesShanxi UniversityTaiyuan030006China

Addressing the challenges posed by the nonlinear and non-stationary vibrations in rotating machinery,where weak fault characteristic signals hinder accurate fault state representation,we propose a novel feature extraction method that combines the Flexible Analytic Wavelet Transform(FAWT)with Nonlinear Quantum Permutation ***,leveraging fractional orders and arbitrary scaling and translation factors,exhibits superior translational invariance and adjustable fundamental oscillatory *** flexibility enables FAWT to provide well-suited wavelet shapes,effectively matching subtle fault components and avoiding performance degradation associated with fixed frequency partitioning and low-oscillation bases in detecting weak *** our approach,gearbox vibration signals undergo FAWT to obtain *** theory is then introduced into permutation entropy to propose Nonlinear Quantum Permutation Entropy,a feature that more accurately characterizes the operational state of vibration simulation *** nonlinear quantum permutation entropy extracted from sub-bands is utilized to characterize the operating state of rotating machinery.A comprehensive analysis of vibration signals from rolling bearings and gearboxes validates the feasibility of the proposed *** assessments with parameters derived from traditional permutation entropy,sample entropy,wavelet transform(WT),and empirical mode decomposition(EMD)underscore the superior effectiveness of this approach in fault detection and classification for rotating machinery.

关键词： Rotating machinery quantum theory nonlinear quantum permutation entropy Flexible Analytic Wavelet Transform(FAWT) feature extraction

来源：

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

limit Theorems for Critical Galton-Watson Processes with Immigration Stopped at Zero

引用

Acta Mathematica Sinica,English Series 2024年第2期40卷 435-450页

作者： Dou Dou li mei ZHANG Xian Yu ZHANG College of Statistics and Data Science Faculty of ScienceBeijing University of TechnologyBeijing 100124P.R.China Laboratory of Mathematics and Complex Systems(Ministry of Education) School of Mathematical SciencesBeijing Normal UniversityBeijing 100875P.R.China

In this paper,we consider a critical Galton-Watson branching process with immigration stopped at zero *** precise estimation on the probability generating function of the n-th population are obtained,and the tail prob... 详细信息

关键词： Branching immigration critical life period limit theorems

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Relevance of hybrid artificial intelligence for improving the forecasting accuracy of natural resource prices

引用

Geoscience Frontiers 2024年第3期15卷 431-446页

作者： mei li Rida Waheed Dervis Kirikkaleli Ghazala Aziz School of Management and Economics and Shenzhen Finance Institute The Chinese University of Hong KongShenzhen(CUHK-Shenzhen)China Department of Finance and Economics College of BusinessUniversity of JeddahJeddahSaudi Arabia European University of Lefke Faculty of Economic and Administrative ScienceDepartment of Banking and FinanceLefkeTurkey Department of Business Administration College of Administrative and Financial SciencesSaudi Electronic UniversityJeddahSaudi Arabia

The prediction performance of traditional forecasting methods is low due to the high level of complexity in a series of energy *** present study attempts to compare the traditional regression,machine learning tools and hybrid models to conclude the outperforming *** first step is to propose the effective denoising technique for Tadawul energy index,which has confirmed the superiority of CSD based ***,we use the CSD-ARIMA,CSD-ANN,and CSD-RNN as hybrid *** a result,CSD-RNN outperforms both other models in terms of MSE,MAPE,RMSE and *** findings are useful for policy makers,investors and portfolio managers to forecast the energy trends,and hedge the portfolio risk accordingly.

关键词： Hybrid artificial intelligence CSD denoising technique Forecasting Energy prices Saudi Arabia

来源：

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

From atomistic modeling to materials design:computation-driven material development in lithium-ion batteries

引用

Science China Chemistry 2024年第1期67卷 276-290页

作者： Xiangrong li Xiang Chen Qiang bai Yifei Mo Yizhou Zhu Research Center for Industries of the Future and School of Engineering Westlake UniversityHangzhou 310030China Department of Chemical Engineering Tsinghua UniversityBeijing 100084China College of Materials Science and Engineering Taiyuan University of TechnologyTaiyuan 030024China Department of Materials Science and Engineering University of MarylandCollege Park 20742United States

As an advanced energy storage system,lithium-ion batteries play an essential role in modern *** their ubiquitous success,there is a great demand for continuous improvements of the battery performance,including higher energy density,lower safety risk,longer cycling life,and lower *** performance improvement requires the design and development of novel electrode and electrolyte materials that exhibit desirable properties and satisfy strict *** modeling can provide a unique perspective to fundamentally understand and rationally design battery *** this paper,we review a few recent successful examples of computation-driven discovery and design in electrode and electrolyte ***,we highlight how atomistic modeling can reveal the underlying mechanisms,predict the important properties,and guide the design and engineering of electrode and electrolyte *** have a conclusion with a discussion of the unique capability of atomistic modeling in battery material development and provide a perspective on future challenges and directions for computation-driven battery material developments.

关键词： materials design computation modeling batteries electrolyte electrode

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Phase Patterning of Poly(oxime-ester)for Information Encryption by Photo-induced Isomerization

引用

Chinese Journal of Polymer Science 2024年第10期42卷 1488-1494,I0010页

作者： Yu-Fan Yang Yun bai Yi-Bao li Chang-Fei He School of Chemistry and Chemical Engineering Gannan Normal UniversityGanzhou341000China

Crystal polymers or liquid crystal elastomers undergo a phase transition that results in a change in the corresponding optical properties,which has the potential to be applied in areas such as information encryption and *** utilization of these materials for patterning purposes requires different phase transition ***,once prepared,altering the phase transition temperature of them presents significant ***,a poly(oxime-ester)(POE)network is developed to achieve high-resolution and multilevel patterning by photo-induced *** as-prepared POE exhibits the ability to transition from an opaque state to a transparent state under temperature stimuli,with the transition temperature and kinetics dependent on UV light exposure ***,complex patterns and information can be encrypted through different selective regional exposure time and decrypted under specific temperature or cooling ***,we illustrate an example of temporal communication,where cooling time or temperature serves as the encoded *** research expands the application scope of advanced encryption materials,showcasing the potential of POE in dynamic information encryption and decryption processes.

关键词： Poly(oxime-ester) Isomerization Phase patterning Information encryption

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Editorial for the Special Issue on Emerging Technology and Advanced Application of Nondestructive Detection for Power Equipment

引用

Chinese Journal of Electrical Engineering 2024年第1期10卷 1-2页

作者： li J. mei H. li S. Tianjin University China Tsinghua Shenzhen International Graduate School China Lanzhou Jiaotong University China

The rapid development of clean and renewable energy technologies represented by wind and solar energy,as well as the continuous growth of load demand,have put forward higher requirements for the safe operation of the power *** performance of power equipment based on traditional dielectric materials is often limited by various defects generated during molding,transportation,assembly,and operation,which cannot meet the reliability requirements of power systems in the new *** detection is an essential technical method in industrial development,which can detect and evaluate the defect and damage status of in-service equipment,key components,and materials without damaging the object.

关键词： service Application operation

来源：

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

Structural and magnetic properties of micropolycrystalline cobalt thin films fabricated by direct current magnetron sputtering

引用

International Journal of Minerals,Metallurgy and Materials 2024年第2期31卷 384-394页

作者： Kerui Song Zhou li mei Fang Zhu Xiao Qian Lei School of Materials Science and Engineering Central South UniversityChangsha 410083China State Key Laboratory of Powder Metallurgy Central South UniversityChangsha 410083China Hunan Key Laboratory of Super-Microstructure and Ultrafast Process School of Physics and electronicsCentral South UniversityChangsha 410083China Key Laboratory of Non-Ferrous Metal Materials Science and Engineering Ministry of EducationChangsha 410083China

Pure cobalt(Co)thin films were fabricated by direct current magnetron sputtering,and the effects of sputtering power and pres-sure on the microstructure and electromagnetic properties of the films were *** the sputtering power increases from 15 to 60 W,the Co thin films transition from an amorphous to a polycrystalline state,accompanied by an increase in the intercrystal pore ***,the resistivity decreases from 276 to 99μΩ·cm,coercivity increases from 162 to 293 Oe,and in-plane magnetic aniso-tropy *** the sputtering pressure decreases from 1.6 to 0.2 Pa,grain size significantly increases,resistivity significantly de-creases,and the coercivity significantly increases(from 67 to 280 Oe),which can be attributed to the increase in defect ***-pondingly,a quantitative model for the coercivity of Co thin films was *** polycrystalline films sputtered under pressures of 0.2 and 0.4 Pa exhibit significant in-plane magnetic anisotropy,which is primarily attributable to increased microstress.

关键词： cobalt thin film magnetron sputtering microstructure electromagnetic properties

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Experimental study on the size effect on the equation of state of concretes under shock loading

引用

Defence Technology（防务技术） 2024年第3期33卷 160-167页

作者： mei li Jian Cui Yanchao Shi baijian Tang Xin Chen Key Laboratory of Coast Civil Structural Safety of the Ministry of Education Tianjin UniversityTianjin 300072China School of Civil Engineering Suzhou University of Science and Technology1701 Binhe RoadSuzhou 215011JiangsuChina School of Civil Engineering Tianjin UniversityTianjin 300072China

Adopting the classical theory of hydrocodes,the constitutive relations of concretes are separated into an equation of state(EoS)which describes the volumetric behavior of concrete material and a strength model which depicts the shear properties of *** experiments on the EoS of concrete is always challenging due to the technical difficulties and equipment limitations,especially for the specimen size effect on the *** some researchers investigate the shock properties of concretes by fly-plate impact tests,the specimens used in their tests are usually in one *** this paper,the fly-plate impact tests on concrete specimens with different sizes are performed to investigate the size effect on the shock properties of concrete *** mechanical background of the size effect on the shock properties are revealed,which is related to the lateral rarefaction effect and the deviatoric stress produced in the *** to the tests results,the modified EoS considering the size effect on the shock properties of concrete are proposed,which the bulk modulus of concrete is unpredicted by up to 20% if size effects are not accounted for.

关键词： Concrete Equation of state Size effect Shock wave Fly-plate impact test

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Visible light-Induced Photocatalysis:Self-Fenton Degradation of p-CIPhOH Over Graphitic Carbon Nitride by a Polyethylenimine Bifunctional Catalyst

引用

Transactions of Tianjin University 2024年第2期30卷 130-139页

作者： Yuan bai Shuangjun li Bolin Yin Jinpeng Zhao Hexing li Key Laboratory of Resource Chemistry of Ministry of Education Shanghai Key Laboratory of Rare Earth Functional MaterialsCollege of Chemistry and Materials ScienceShanghai Normal UniversityShanghai 200234China

Deep degradation of organic pollutants by sunlight-induced coupled photocatalytic and Fenton (photo-Fenton) reactions is of immense importance for water purification. In this work, we report a novel bifunctional catalyst (Fe-PEI-CN) by codoping graphitic carbon nitride (CN) with polyethyleneimine ethoxylated (PEI) and Fe species, which demonstrated high activity during p-chlorophenol (p-ClPhOH) degradation via H_(2)O_(2) from the photocatalytic process. The relationship between the catalytic efficiency and the structure was explored using diff erent characterization methods. The Fe modification of CN was achieved through Fe-N coordination, which ensured high dispersion of Fe species and strong stability against leaching during liquid- phase reactions. The Fe modification initiated the Fenton reaction by activating H_(2)O_(2) into ·OH radicals for deep degradation of p-ClPhOH. In addition, it eff ectively promoted light absorption and photoelectron-hole (e-h ^(+) ) separation, corresponding to improved photocatalytic activity. On the other hand, PEI could significantly improve the ability of CN to generate H_(2)O_(2) through visible light photocatalysis. The maximum H_(2)O_(2) yield reached up to 102.6 μmol/L, which was 22 times higher than that of primitive CN. The cooperation of photocatalysis and the self-Fenton reaction has led to high-activity mineralizing organic pollutants with strong durability, indicating good potential for practical application in wastewater treatment.

关键词： Fe-PEI-CN bifunctional catalyst Photo-Fenton p-chlorophenol(p-ClPhOH)degradation Synergetic effect

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Chemical Activation of S/li2S in li-S Batteries by a Bidirectional Organic Redox Mediator

引用

Chemical Research in Chinese Universities 2024年第5期40卷 927-934页

作者： li Chengqiu ZHOU Chaoyong mei Shilin YAO Changjiang State Key Laboratory of Explosion Science and Safety Protection School of Mechatronical EngineeringBeijing Institute of TechnologyBeijing100081P.R.China Xi’an Safty Energy Technology Co. Ltd.Xi’an710299P.R.China

The energy density and lifespan of prototype li-S batteries under high sulfur loading and lean electrolyte have been mainly restricted by the incomplete interconversion between insulating S8 and *** introduction of an electrocatalyst has been preserved as an effective way to breakthrough the bottleneck of the interconversion ***,we demonstrate a novel bidirectional redox mediator,insoluble dithiobisphthalimide(DTPI),as the electrocatalyst for both S8 reduction and li2S *** to the dual-functional role of both electron/li^(+)donor and acceptor,DTPI can efficiently accelerate the redox reactions during charge/discharge and significantly alleviate the incomplete conversion of sulfur ***,the li-S batteries with DTPI deliver superior specific capacity and cycling stability in comparison with those without ***,the redox mediator is scalable for synthesis and the DTPI-based 5 A·h pouch cell delivers a specific discharge capacity of around 870 mA·h·g^(−1) at 0.1 C(1 C=1675 mA/g)without capacity fading over 80 *** bidirectional catalysis mechanism has been studied through theoretical calculation and ex-situ characterization of the cathode *** work approves the effectiveness of bidirectional organic redox mediator in the construction of practical li-S batteries.

关键词： lithium-sulfur battery(LSB) Dithiobisphthalimide(DTPI) Organic redox mediator Interconversion

来源：

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

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：