电路与系统(英文)最新文献_第2页

A High-Speed DLL-Based Hybrid Phase Conjugator for 5G Beamforming 一种用于5G波束形成的高速dll混合相位共轭器

电路与系统(英文) Pub Date : 2020-03-31 DOI: 10.4236/cs.2020.113003

Michael Bolt, M. Adams

引用次数: 1

CMOS Realization of VDTA Based Electronically Tunable Wave Active Filter with Minimum Power Consumption at Low Supply Voltage ±0.82 V 在±0.82 V低电压下，基于VDTA的最小功耗电子可调谐有源滤波器的CMOS实现

电路与系统(英文) Pub Date : 2020-02-28 DOI: 10.4236/cs.2020.112002

G. Singh

引用次数: 2

A Multimedia Based Virtual Learning System: A Panacea for Nigerian Tertiary Institutions 一个基于多媒体的虚拟学习系统：尼日利亚高等院校的灵丹妙药

电路与系统(英文) Pub Date : 2020-01-31 DOI: 10.4236/cs.2020.111001

E. Ekwonwune, Chidiebere Chukwuma Oparah

{"title":"A Multimedia Based Virtual Learning System: A Panacea for Nigerian Tertiary Institutions","authors":"E. Ekwonwune, Chidiebere Chukwuma Oparah","doi":"10.4236/cs.2020.111001","DOIUrl":"https://doi.org/10.4236/cs.2020.111001","url":null,"abstract":"Multimedia based virtual learning system (MMVLS) is a web-based platform for teaching and learning with a virtual teacher within a virtual classroom. This research was motivated by the problems confronting the traditional institutions of higher learning in Nigeria which include inadequate funding, lack of infrastructures, inadequate teaching and learning facilities, limited slots for admission known as carrying capacity, a limited number of lecturers/instructors in the tertiary institutions in Nigeria. The objective of this research is to develop a multimedia based virtual learning system for Nigerian tertiary institutions to be used in academic processes for teaching and learning. The methodology used is Object Oriented Design Methodology (OODM) with the following web development tools PHP, JavaScript, Bootstrap 3, HTML5, CSS4, Apache, and MYSQL as database. The expected result is a multimedia based virtual learning system for tertiary institutions in Nigeria which is cost effective, innovative, vibrant, individualized, learner-centric, available anytime, any place even with mobile devices. It was concluded that multimedia based virtual learning system is a veritable tool for Nigerian tertiary institutions, which when fully implemented by Nigerian tertiary institutions would help to increase the number of candidates that are given admission into our tertiary institutions and drastically reduce school dropouts as a result of candidates not gaining admission due to insufficient tertiary institutions/carrying capacity.","PeriodicalId":63422,"journal":{"name":"电路与系统(英文)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45421692","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 3

Square Patch Antenna for Breast Cancer Diagnosis at 2.45 GHz 2.45 GHz方形贴片天线用于乳腺癌诊断

电路与系统(英文) Pub Date : 2019-04-30 DOI: 10.4236/cs.2019.104004

Mussa Elsaadi, Hend Muhmed, Mohammed Abd Alraheem, Hajir Miftah, Omar Salah

引用次数: 3

Hyperthermia for Breast Cancer Treatment Using Slotted Circular Patch Antenna 开槽环形贴片天线用于癌症热疗

电路与系统(英文) Pub Date : 2019-03-29 DOI: 10.4236/cs.2019.103003

Mussa Elsaadi, Yousef Aid, Mustafa Abbas, Amani Embarek, Khaleel Salih

引用次数: 6

A Comparison Study of Diode-String ESD Clamps for CMOS Input Protection 用于CMOS输入保护的二极管串式ESD钳位的比较研究

电路与系统(英文) Pub Date : 2019-02-28 DOI: 10.4236/cs.2019.102002

J. Choi

{"title":"A Comparison Study of Diode-String ESD Clamps for CMOS Input Protection","authors":"J. Choi","doi":"10.4236/cs.2019.102002","DOIUrl":"https://doi.org/10.4236/cs.2019.102002","url":null,"abstract":"Based on 2-D device simulations and mixed-mode transient simulations, DC and transient discharge characteristics of a usual diode string utilizing a standard CMOS process, and a diode string utilizing a triple-well CMOS process, which can serve as an essential VDD-VSS clamp device for CMOS input ESD protection were compared. Transient discharge characteristics including peak voltages developed across gates oxides of transistors in input buffers, lattice heating inside ESD protection devices, and ratios of discharge current components at its peak inside the diode-string clamp were compared. DC standby current levels added per each input pad structure, which are the critical parameters determining usefulness of the devices, were also compared. We showed that the diode-string devices in comparison can serve successfully as a VDD-VSS clamp device for ESD protection by virtue of the dominant pnpn thyristor-related conduction mechanisms. Optimization of design parameters including anode-cathode contact spacing in each diode in the string, device width of the diode string, and number of diodes in the diode string was performed to present transient discharge and DC characteristics of some recommendable design examples, which can serve as a guideline in designing diode-string clamp devices.","PeriodicalId":63422,"journal":{"name":"电路与系统(英文)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47751751","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Grid-Connected Emergency Back-Up Power Supply 并网应急备用电源

电路与系统(英文) Pub Date : 2019-01-31 DOI: 10.4236/CS.2019.101001

Dhiman Chowdhury, M. Miah, Md. Feroz Hossain, Md. Mostafijur Rahman, M. J. Hossain, Md. Nazim Uddin Sheikh, M. Hasan, Uzzal Sarker, A. Hasan

{"title":"Grid-Connected Emergency Back-Up Power Supply","authors":"Dhiman Chowdhury, M. Miah, Md. Feroz Hossain, Md. Mostafijur Rahman, M. J. Hossain, Md. Nazim Uddin Sheikh, M. Hasan, Uzzal Sarker, A. Hasan","doi":"10.4236/CS.2019.101001","DOIUrl":"https://doi.org/10.4236/CS.2019.101001","url":null,"abstract":"This paper documents design and modeling of a grid-connected emergency back-up power supply for medium power applications. Back-up power supplies are very important in regard to support electrical loads in the events of grid power outage. However, grid-integration of a back-up power supply substantiates continual power transfer to the loads, especially to the critical loads, which should not suffer from power interruptions. Therefore, design and circuit modeling of switching converters based reliable grid-tied emergency back-up power supply are presented in this paper. There are a rectifier-link boost derived battery charging circuit and a 4-switch push-pull power inverter circuit which are controlled by high frequency pulse width modulation (PWM) signals. This paper presents a state averaging model and Laplace domain transfer function of the charging circuit and a switching converter model of the power inverter circuit. A changeover relay based transfer switch controls the power flow towards the utility loads. During off-grid situations, loads are fed power by the proposed inverter circuit and during on-grid situations, battery is charged by an ac-link rectifier-fed boost converter. However, there is a relay switching circuit to control the charging phenomenon of the battery. The proposed design is simulated in PLECS and the simulation results corroborate the reliability of the presented framework.","PeriodicalId":63422,"journal":{"name":"电路与系统(英文)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43696317","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

A Temperature-Based Hysteresis Buck Converter for Dynamic Current Sharing 一种基于温度的动态电流共享迟滞Buck变换器

电路与系统(英文) Pub Date : 2018-12-27 DOI: 10.4236/cs.2018.912019

Long Zhang, Hong-Chong Wu, Ching-Hwa Cheng, Don-Gey Liu, M. Shiau, Weidian Lai, Ziwei Zheng

引用次数: 0

Simulation of Space Charge Impact on Partial Discharge Inception Voltage in Power Busbars Dedicated to Future Hybrid Aircrafts 空间电荷对未来混合动力飞行器电源母线局部放电起始电压影响的仿真

电路与系统(英文) Pub Date : 2018-11-27 DOI: 10.4236/CS.2018.911018

M. Banda, D. Malec, J. Cambronne

{"title":"Simulation of Space Charge Impact on Partial Discharge Inception Voltage in Power Busbars Dedicated to Future Hybrid Aircrafts","authors":"M. Banda, D. Malec, J. Cambronne","doi":"10.4236/CS.2018.911018","DOIUrl":"https://doi.org/10.4236/CS.2018.911018","url":null,"abstract":"Reducing greenhouse gases, saving energy resources and mass optimization require technological changes towards increasingly electric vehicles. At the same time, performance improvement of semiconductor and dielectric materials further promotes electronic components confinement, resulting in a significant increase of embedded power densities. In the particular case of future hybrid propulsion aircrafts, electrical power that intended to supply reactors would be converted through power electronics components mounted on power busbars and insulated by solid dielectrics materials. These dielectrics materials have to respond to various electrical constraints of use (HVDC), in spite of environment change of aircraft parameters such as low pressure, temperature and thermal cycles, humidity... Unfortunately, partial discharges phenomenon is the most problem within electrical insulation system (EIS). Based on a topological model of power busbars designed for power converters dedicated to hybrid aircraft, partial discharge studies were conducted by simulation in various charging conditions of a PTFE insulator. Simulation results, which focus on electric field thresholds criteria of partial discharge inception voltage in air, reveal a net sensitivity of a space charge accumulation and distribution on dielectrics behaviour even for low space charge density, depending on their location in dielectrics. Compared to the behaviour observed with implanted homocharges, when by increasing homocharges density from 0.5 C/m3 to 2 C/m3 we observe a decrease of electric field by 450%, simulation results show a highest risk of partial discharge inception when heterocharges are accumulated inside dielectrics. Their accumulation increases the electric field in triple points beyond electric field thresholds of partial discharge inception in air. The simulated electric field reaching 22 kV/mm with only 2 C/m3 of heterocharges density accumulated in dielectric/busbars interfaces.","PeriodicalId":63422,"journal":{"name":"电路与系统(英文)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41481353","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Stabilization of Linear Multistage Amplifiers 线性多级放大器的稳定性

电路与系统(英文) Pub Date : 2018-11-12 DOI: 10.4236/CS.2018.911017

Janos Ladvanszky

引用次数: 1