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Abnormal enhancement to the quality factors of carbon nanotube via defects engineering

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Nano Materials Science 2022年第3期4卷 259-265页

作者： Ke Duan Li Li Sihan Liu Yujin Hu Xuelin Wang State Key Lab of Digital Manufacturing Equipment and Technology School of Mechanical Science and EngineeringHuazhong University of Science and TechnologyWuhan430074China

Low quality(q) factor is often the limiting factor for high performance carbon nanotube(CNT) resonators. The most commonly used approach to enhance the q factor of CNTs is to reduce/eliminate the intrinsic ***, we show surprisingly that hole defects of suitable size and position are able to enhance the q factor of CNT, which strongly contradicts to the common notion that the presence of defects promote intrinsic dissipation via defects dissipation. By analyzing the strain distribution, we find that such abnormal enhancement in q factor of defected CNT originates from a coupling competition mechanism between the atomic mismatch around defected atoms and the thermoelastic damping. Although the presence of holes will introduce an additional defect dissipation source, suitable holes are capable of reducing the energy dissipation arisen from the thermoelastic damping, through changing the spatial strain field of defected CNT. This coupling competition mechanism provides a new route for designing high performance CNT resonators via defects engineering.

关键词： Defects engineering CNT resonator q factor

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Plasmon-induced transparency in terahertz metamaterials

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Science China(Information Sciences) 2013年第12期56卷 73-90页

作者： JING HuiHui ZHU ZhiHua ZHANG Xueqian GU Jianqiang TIAN Zhen OUYANG ChunMei HAN JiaGuang ZHANG WeiLi Center for Terahertz waves and College of Precision Instrument and Optoelectronics Engineering Tianjin University and the Key Laboratory of Optoelectronics Information Technology (Ministry of Education) School of Electrical and Computer Engineering Oklahoma State University

The quantum phenomena of electromagnetically induced transparency(EIT)or plasmonic analogue of electromagnetically induced transparency(PIT)can be mimicked in the classical resonators,leading to a unique way to explore the coherent coupling mechanism in metamaterial *** metamaterial structures have been proposed to excite and manipulate the PIT efect with flexibility and performance with geometry-controllable,polarization-independent,broadband-transparency and active-modulated *** in turn promise the fascinating functionalities and applications of the PIT efects,such as slow-light components,nonlinear devices and high-sensitivity ***,we present a review on the progress in developing the PIT efect in terahertz metamaterials over the past few years.

关键词： PIT terahertz metamaterial q factor plasmon coupling

Mn0.8Zn0.2Fe2O4 nanoparticulates spinel ferrites:An approach to enhance the antenna field strength for improved magnitude versus offset(MVO)

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Progress in Natural Science:Materials International 2014年第4期24卷 364-372页

作者： Majid Niaz Akhtar Nadeem Nasir Muhammad Kashif Noorhana Yahya Mukhtar Ahmad Ghulam Murtaza Muhammad Azhar Khan M.H.Asif A.Sattar R.Raza M.Saleem S.N.Khan Department of Physics COMSATS Institute of Information Technology Electrical and Electronic Engineering Department Universiti Teknologi PETRONAS Fundamental and Applied Sciences Department National Textile University Fundamental and Applied Sciences Department Universiti Teknologi PETRONAS Centre for Advanced Studies in Physics G.C.University Department of Physics The Islamia University of Bahawalpur

Electromagnetic signals in deep reservoir are very weak so that it is difficult to predict about the presence of hydrocarbon in seabed logging(SBL) *** the present work,Mn0.8Zn0.2Fe2O4 nanoferrites were prepared by a sol–gel technique at different sintering temperatures of450 °C,650 °C and 850 °C to increase the strength of electromagnetic(EM) ***,FESEM,Raman spectroscopy and HRTEM were used to analyze the phase,surface morphology and size of the *** properties of the nanoferrites were also measured using an impedance network ***,nanoferrites sintered at 850 °C with initial permeability of 200 and q factor of 50 were used as magnetic feeders with the EM *** scale experiments were performed to investigate the effect of magnetic field strength in scale *** and MATLAB softwares were also used to confirm the oil presence in scale *** was observed that the magnitude of the EM waves for the antenna was increased up to 233%.Finally,the correlation values also show 208% increase in the magnetic field strength with the presence of the ***,antenna with Mn0.8Zn0.2Fe2O4 nanoferrites based magnetic feeders can be used for deep water and deep target hydrocarbon exploration.

关键词： Nanoferrites Transmission Electron Microscopy Initial permeability q factor Antenna

Measuring Crustal Lg-Waves Attenuation in the Northern Part of Africa

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Open Journal of Earthquake Research 2016年第2期5卷 105-113页

作者： Adoum Issak Christian Camerlynck Faculté des Sciences Exactes et Appliquées N’Djamena Tchad Sorbonne Universités UPMC Univ Paris 6 Paris France

Lg-waves propagate over long distances in the northern part of Africa and are recorded on the seismic station located close to Abeche (Chad). We have applied the well-known coda analysis method developed by Aki and Chouet [1] to study the Lg-wave anelastic attenuation in this area. We found a frequency dependence: q( f ) = (650±34) f (0.77±0.2). This result shows an average value of q0 (q0 ≈ 650) for earthquakes occurred in tectonic areas as the East African Rift system, Turkey, Greece and Red Sea. The higher value of q0 (q0 ≈ 800) is obtained for the event occurred in the middle of the stable plate close to the Tamanrasset (TAM) station in Algeria.

关键词： Lg-Wave Attenuation Coda q factor North Africa

Research on Dispersion Compensation of 40 GB/s Optical Duo-Binary Coded Transmission System

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Optics and Photonics Journal 2016年第8期6卷 190-195页

作者： Yue Zhou Yufeng Shao Zhifeng Wang Changxiang Li Junyi Zhou Wenzhe Ma Faculty of Engineering Shanghai Polytechnic University Shanghai China

A 40 Gb/s high speed optical transmission system is designed, and the different dispersion compensation schemes are adopted to realize the transmission of the optical duo-binary (ODB) signals over 120 km optical fiber. Optical duo-binary signals are generated by using a precoder, two low- pass filters (LPF) and one mach-zehnder modulator (MZM). Through combination of dispersion compensation fiber (DCF) and single mode fiber (SMF) in the transmission link, four different dispersion compensation schemes (pre-compensation, post-compensation and hybrid compensation (pre+ post) and hybrid compensation (post+ pre)) were compared. Analyzing q factor, BER, eye diagrams and receiver sensitivity in several dispersion compensation schemes, the simulation results are: the cut-off frequency of LPF affects the transmission performance, and the hybrid compensation (post+ pre) scheme is the optimal dispersion compensation method.

关键词： Optical Communication Duo-Binary Dispersion Compensation q factor Eye Diagrams

Modeling and Analysis of Penalty on Optical Signal Performance Duo to Low-Frequency Subcarriers Multiplexing

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Modeling and Analysis of Penalty on Optical Signal Performan...