检索结果-南通市图书馆

Improved Control in Single Phase Inverter Grid-Tied PV System Using Modified PQ Theory

Intelligent Automation & Soft Computing 2023年第8期37卷 2441-2457页

作者： Nur Fairuz mohamed Yusof Dahaman Ishak Muhammad Ammirrul Atiqi Mohd Zainuri Muhammad Najwan Hamidi Zuhair Muhammed Alaas mohamed mostafa ramadan ahmed Faculty of Electrical Engineering&Technology Universiti Malaysia Perlis02600ArauMalaysia School of Electrical&Electronic Engineering Universiti Sains Malaysia14300Nibong TebalMalaysia Department of Electrical Electronic and Systems EngineeringFaculty of Engineering and Built EnvironmentUniversiti Kebangsaan MalaysiaSelangor43600Malaysia School of Engineering Jazan UniversityJazanSaudi Arabia Faculty of Technology and Education Helwan UniversityCairoEgypt

Grid-connected reactive-load compensation and harmonic control are becoming a central topic as photovoltaic(PV)grid-connected systems *** research aims to produce a high-performance inverter with a fast dynamic response for accurate reference tracking and a low total har-monic distortion(THD)even under nonlinear load applications by improving its control *** proposed system is expected to operate in both stand-alone mode and grid-connected *** stand-alone mode,the proposed controller supplies power to critical loads,alternatively during grid-connected mode provide excess energy to the utility.A modified variable step incremental conductance(VS-InCond)algorithm is designed to extract maximum power from *** the proposed inverter controller is achieved by using a modified PQ theory with double-band hysteresis current controller(PQ-DBHCC)to produce a reference current based on a decomposition of a single-phase load *** nonlinear rectifier loads often create significant distortion in the output voltage of single-phase inverters,due to excessive current harmonics in the ***,the proposed method generates a close-loop reference current for the switching scheme,hence,minimizing the inverter voltage distortion caused by the excessive grid current *** simulation findings suggest the proposed control technique can effectively yield more than 97%of power conversion efficiency while suppressing the grid current THD by less than 2%and maintaining the unity power factor at the grid *** efficacy of the proposed controller is simulated using MATLAB/Simulink.

关键词： Hysteresis current controller incremental conductance nonlinear load PQ theory single-phase inverter

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

Friction and wear of sand-contaminated lubricated sliding

引用

Friction 2018年第4期6卷 457-463页

作者： mohamed ahmed ramadan Faculty of Engineering at Helwan Helwan University

This paper reports a test investigation of friction and wear responses from sand contaminated lubricated sliding. The influence of sand contaminants on wear and friction is characterized. Analyses are completed utilizing segments of piston ring sliding against the cylinder liner. Paraffin oil, with and without sand contaminants, is utilized. The effects of the concentration and particle size of sand are examined. Based on the observations in the present work, we found that friction and wear increase with sand concentration in the lube. Solid proposals ought to be considered, in order to enlighten the general population on the importance of changing a car engine's oil filter regularly.

关键词： sand contamination lubrication oil abrasive wear lubricated sliding

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

Direct Power Control Based on Dead-beat Function and Extended Kalman Filter for PV Systems

引用

Journal of Modern Power Systems and Clean Energy 2023年第3期11卷 863-872页

作者： mostafa ahmed Ibrahim Harbi Ralph Kennel mohamed Abdelrahem Chair of High-Power Converter Systems(HLU) Technical University of Munich(TUM)80333 MunichGermany Department of Electrical Engineering Faculty of EngineeringAssiut UniversityAssiut 71515Egypt Department of Electrical Engineering Faculty of EngineeringMenoufia UniversityShebin El-Koum 32511Egypt IEEE

In this paper,a new proposal for the implementation of the well-known direct power control(DPC)technique in grid-connected photovoltaic(PV)systems is ***,the DPC is executed using a look-up table procedure based on the error between the actual and reference values of the active and reactive ***,the structure of the DPC is simple and results in a fast transient behavior of the inner current loop(injected currents).Therefore,in the current study,the DPC is reformulated using a dead-beat *** this formulation,the reference voltage vector(RVV)is obtained in theα-βreference ***,the switching states for the inverter can be obtained based on the sign of the components of the *** suggested DPC is compared with the conventional one and other switching tables,which are intended for performance ***,an extended Kalman filter(EKF)is utilized to eliminate all grid-voltage ***,the switching frequency of the proposed technique is minimized without any need for weighting factors or cost function *** overall control technique is validated using a hardware-in-the-loop(HIL)experimental set-up and compared with other schemes under different operating conditions.

关键词： Photovoltaic(PV)system direct power control(DPC) sensorless control switching frequency minimization weighting factor

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

Solar thermochemical reactions Ⅱ:Synthesis of 2-aminothiophenes via Gewald reaction induced by solar thermal energy

引用

Chinese Chemical Letters 2008年第7期19卷 788-790页

作者： ramadan ahmed Mekheimer mohamed Abdallah Ameen Kamal Usef Sadek Chemistry Department Faculty of ScienceEl-Minia UniversityEl-Minia 61519Egypt

Green conditions have been developed for the synthesis of substituted 2-aminothiophenes employing multicomponent reactions of a ketone with active methylene nitrile and elemental sulphur induced by free solar thermal ... 详细信息

关键词： 2-Aminothiophenes Gewald reaction Solar thermal energy

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

Cartilage tympanoplasty in the treatment of adhesive otitis media with and without Eustachian tube balloon dilatation

引用

Journal of Otology 2022年第4期17卷 226-231页

作者： ahmed abdel rahman abdel aziz ahmed Mahmoud Youssef mostafa mohamed mostafa mostafa talaat Khaled mohamed Abdelzaher ahmed Adel Sadeq Department of Otorhinolaryngology Faculty of MedicineEl MiniaEgypt Radiology Department Faculty of MedicineEl MiniaEgypt

Purpose:To compare cartilage tympanoplasty(CT)combined with eustachian tube balloon dilatation(ETBD)and cartilage tympanoplasty alone as a surgical treatment modality for adhesive otitis media(AdOM)in terms of graft healing,audiological outcomes,and impact on life style,using Chronic Otitis Media Outcome Test 15(COMOT-15).Methods:50 patients with AdOM were randomly classified into 2 groups:25 patients for cartilage tympanoplasty only(CT group)and 25 patients for cartilage tympanoplasty combined with eustachian tube balloon dilatation(CT t ETBD group).Clinical outcomes in both groups were compared at 3 and 6 months of follow ***:There was no significant difference in graft healing between the two *** COMOT-15 scores significantly decreased in both groups with a significant difference between the groups with regard to the decrease in COMOT-15 scores at 3 and 6 months of follow-up(P<0.05).Hearing improvement was achieved,as the mean preoperative ABG was 26.5±5.4 and 27.1±4.6 dB,and the mean postoperative ABG at 6 months was 19.4±4.4 and 14.6±3.9 dB in the CT and the CT t ETBD groups,*** difference in the magnitude of ABG reduction in the two groups was significant at 3 and 6 months of postoperative follow-up(P<0.05)in favour of the CT t ETBD ***:ETBD can increase the success rate of cartilage tympanoplasty in patients with AdOM by enhancing the audiological outcome and quality of life.

关键词： balloon healing otitis

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

Patterns of liver profile disturbance in patients with COVID-19

引用

World Journal of Clinical Cases 2022年第7期10卷 2063-2071页

作者： Hend Ibrahim Shousha ahmed ramadan Rania Lithy mohamed El-Kassas Department of Endemic Medicine Faculty of MedicineCairo UniversityCairo 12556Egypt Department of Endemic Medicine Faculty of MedicineHelwan UniversityCairo 11795Egypt

Fever and cough are the most common clinical symptoms of coronavirus disease 2019(COVID-19),but complications(such as pneumonia,respiratory distress syndrome,and multiorgan failure)can occur in people with additional ***-19 may be a new cause of liver disease,as liver profile disturbance is one of the most common findings among *** molecular mechanism underlying this phenomenon,however,is still *** this paper,we review the most current research on the patterns of change in liver profile among patients with COVID-19,the possible explanation for these findings,and the relation to pre-existing liver disease in these patients.

关键词： Liver functions COVID-19 Liver profile Alanine transaminase aspartate transaminase Bilirubin

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

Induction of sub-G0 arrest and apoptosis by seed extract of Moringa peregrina（Forssk.） Fiori in cervical and prostate cancer cell lines

引用

Journal of Integrative Medicine 2019年第6期17卷 410-422页

作者： Maged mohamed Maher Abou-Hashem Dina mohamed Abo-elmatty Noha mostafa Mesbah ahmed mohamed Abd EL-Mawgoud Faculty of Pharmacy Pharmacognosy DepartmentZagazig UniversityZagazig 44511Egypt Faculty of Pharmacy Biochemistry DepartmentSuez Canal UniversityIsmailia 41522Egypt Egyptian International Pharmaceuticals Industries Company Tenth of Ramadan City 44629Egypt

Objective: This study investigated cytotoxicity and induction of apoptosis in human cervical cancer cells(HELA) and prostate cancer cells(PC-3) using the most active fraction of Moringa peregrina seed ***: Dried and powdered seeds were extracted using 95% ethanol. The total ethanolic extract was further dissolved in distilled water and separated into petroleum ether, chloroform, ethyl acetate and aqueous extracts. Based on the results of in vitro anticancer studies of all extracts, the most highly active extract was selected for evaluation of apoptosis induction and cell cycle analysis on HELA and PC-3 cells at its half maximal inhibitory concentration using flow cytometry;DNA fragmentation by agarose gel electrophoresis and the expression of protein were measured by Western ***: The chloroform fraction from the ethanolic extract of M. peregrina(CFEE) was the most active antitumor fraction. The selectivity index, determined using the normal Vero cell line, indicated that CFEE had a high degree of selectivity against HELA and PC-3 cells. CFEE induced apoptosis, confirmed by cell cycle arrest at sub-G0 phase and DNA fragmentation. CFEE induced an increase in mRNA expression of caspase-3, a decrease in Bcl-2 mRNA expression, and decreased ATP levels. CFEE increased protein expression of caspase-3 and decreased protein expression of poly-ADP-ribose polymerase-1(PARP-1).Flow cytometric analysis showed an appreciable increase in the number of cells in the early apoptotic stage in CFEE-treated HELA and PC-3 cells. CFEE treatment significantly increased lipid peroxidation(malondialdehyde level) in HELA and PC-3 ***: Seed extract of M. peregrina displayed a significant antitumor effect through apoptosis induction in HELA and PC-3 cells.

关键词： Moringa peregrina Fractionation Antiproliferation Apoptosis

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

Gut virome:New key players in the pathogenesis of inflammatory bowel disease

引用

World Journal of Methodology 2025年第2期15卷 27-43页

作者： Helal F Hetta Rehab ahmed Yasmin N ramadan Hayam Fathy Mohammed Khorshid mohamed M Mabrouk Mai Hashem Department of Medical Microbiology and Immunology Faculty of MedicineAssiut UniversityAssiut 71515Egypt Division of Microbiology Immunology and BiotechnologyFaculty of pharmacyUniversity of TabukTabuk 71491Saudi Arabia Division of Microbiology Immunology and BiotechnologyDepartment of Natural Products and Alternative MedicineFaculty of PharmacyUniversity of TabukTabuk 71491Saudi Arabia Department of Internal Medicine Division HepatogastroenterologyAssiut UniversityAssiut 71515Egypt Department of Clinical Research Egyptian Developers of Gastroenterology and Endoscopy FoundationCairo 11936Egypt Department of Internal Medicine Faculty of Medicine.Tanta UniversityTanta 31527Egypt Department of Tropical Medicine Gastroenterology and HepatologyAssiut University HospitalAssiut 71515Egypt

Inflammatory bowel disease(IBD)is a chronic inflammatory illness of the *** the mechanism underlying the pathogenesis of IBD is not fully under-stood,it is believed that a complex combination of host immunological response,environmental exposure,particularly the gut microbiota,and genetic suscept-ibility represents the major *** gut virome is a group of viruses found in great frequency in the gastrointestinal tract of *** gut virome varies greatly among individuals and is influenced by factors including lifestyle,diet,health and disease conditions,geography,and *** majority of research has focused on the significance of gut bacteria in the progression of IBD,although viral populations represent an important component of the *** conducted this review to highlight the viral communities in the gut and their expected roles in the etiopathogenesis of IBD regarding published research to date.

关键词： Inflammatory bowel disease Pathogenesis Gut virome Bacteriophage Eukaryotic viruses

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

Comparative study between three carbonaceous nanoblades and nanodarts for antimicrobial applications

引用

Journal of Environmental Sciences 2024年第2期136卷 594-605页

作者： mohamed S.Selim ahmed M.Azzam mohamed A.Shenashen Shimaa A.Higazy Bayaumy B.mostafa Sherif A.El-Safty National Institute for Materials Science(NIMS) 1-2-1 SengenTsukuba-ShiIbaraki-Ken 305-0047Japan Petroleum Application Department Egyptian Petroleum Research InstituteNasr City 11727Egypt Department of Environmental Research Theodor Bilharz Research InstituteGizaEgypt

The design of nanostructured materials occupies a privileged position in the development and management of affordable and effective technology in the antibacterial ***,we discuss the antimicrobial properties of three carbonaceous nanoblades and nanodarts materials of graphene oxide(GO),reduced graphene oxide(RGO),and single-wall carbon nanotubes(SWCNTs)that have a mechano-bactericidal effect,and the ability to piercing or slicing bacterial *** demonstrate the significance of size,morphology and composition on the antibacterial activity mechanism,the designed nanomaterials have been *** minimum inhibitory concentration(MIC),standard agar well diffusion,and transmission electron microscopy were utilized to evaluate the antibacterial activity of GO,RGO,and *** on the evidence obtained,the three carbonaceous materials exhibit activity against all microbial strains tested by completely encapsulating bacterial cells and causing morphological disruption by degrading the microbial cell membrane in the order of RGO>GO>*** of the external cell wall structure and outer membrane proteins,the synthesized carbonaceous nanomaterials exhibited higher antibacterial activity against Gram-positive bacterial strains than Gram-negative and fungal *** had the lowest MIC values(0.062,0.125,and 0.25 mg/mL against ***,***,and ***,respectively),as well as minimum fungal concentrations(0.5 mg/mL for both *** and ***).At 12 hr,the cell viability values against tested microbial strains were completely *** lysis and death occurred as a result of severe membrane damage caused by microorganisms perched on RGO *** work gives an insight into the design of effective graphene-based antimicrobial materials for water treatment and remediation.

关键词： Antimicrobial properties Nanoblades Mechano-bactericidal effect RGO nanosheets Gram-positive bacteria Cell viability

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

Path planning for moving target tracking by fixed-wing UAV

引用

Defence Technology（防务技术） 2020年第4期16卷 811-824页

作者： Song-lin Liao Rong-ming Zhu Nai-qi Wu Tauqeer ahmed Shaikh mohamed Sharaf Almetwally M.mostafa School of Electro-Mechanical Engineering Xidian UniversityXi'an 710071China Institute of Systems Engineering Macao University of Science and TechnologyTaipa999078Macao Electrical Engineering Department College of EngineeringKing Saud UniversityRiyadh 11421Saudi Arabia Industrial Engineering Department College of EngineeringKing Saud UniversityP.O.Box 800Riyadh 11421Saudi Arabia College of Computer and Information Sciences King Saud UniversityP.O.Box 800Riyadh 11421Saudi Arabia Faculty of Engineering Alazhar University CairoEgypt

For the automatic tracking of unknown moving targets on the ground,most of the commonly used methods involve circling above the *** such a tracking mode,there is a moving laser spot on the target,which will bring trouble for cooperative manned *** this paper,we propose a new way of tracking,where an unmanned aerial vehicle(UAV) circles on one side of the tracked target.A circular path algorithm is developed for monitoring the relative position between the UAV and the target considering the real-time range and the bearing *** can determine the center of the new circular path if the predicted range between the UAV and the target does not meet the monitoring requirements.A transition path algorithm is presented for planning the transition path between circular paths that constrain the turning radius of the *** transition path algorithm can generate waypoints that meet the flight *** this paper,we analyze the entire method and detail the scope of *** formulate an observation angle as an evaluation index.A series of simulations and evaluation index comparisons verify the effectiveness of the proposed algorithms.

关键词： Bearing angle Fixed-wing UAV Laser designation Moving target tracking Path planning

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

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：