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Effects of material and Dimension on TCF,Frequency,and Q of Radial Contour mode AlN-on-Si mEmS Resonators

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Journal of Electronic Science and Technology 2021年第4期19卷 319-334页

作者： Thi Dep ha with the Faculty of Electronics Technology Industrial University of Ho Chi Minh CityHo Chi Minh City 70000

This paper investigates the effects of material and dimension parameters on the frequency splitting,frequency drift,and quality factor(Q)of aluminium nitride(AlN)-on-n-doped/pure silicon(Si)microelectromechanical systems(mEmS)disk resonators through analysis and *** parameters include the crystallographic orientation,dopant,substrate thickness,and *** resonators operate in the elliptical,higher order,and flexural *** simulation results show that i)the turnover points of the resonators exist at 55°C,-50°C,40°C,and-10°C for n-doped silicon with the doping concentration of 2×1019 cm-3 and the Si thickness of 3.5μm,and these points are shifted with the substrate thickness and mode variations;ii)compared with pure Si,the modal-frequency splitting for n-doped Si is higher and increases from 5%to 10%for all studied modes;iii)Q of the resonators depends on the temperature and ***,the turnover,modal-frequency splitting,and Q of the resonators depend on the thickness and material of the substrate and the *** work offers an analysis and design platform for high-performance mEmS gyroscopes as well as oscillators in terms of the temperature compensation by n-doped Si.

关键词： Anisotropic contour mode doping gyroscope microelectromechanical systems(mEmS)resonator piezoelectric temperature coefficient of frequency(TCF) temperature compensation thin-film piezoelectric-on-substrate(TPoS)

Support vector machine based machine learning method for GS 8QAm constellation classification in seamless integrated fiber and visible light communication system

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Science China(Information Sciences) 2020年第10期63卷 182-193页

作者： Wenqing NIU Yinaer ha Nan CHI Key Laboratory for Information Science of Electromagnetic Waves (moE) Fudan University

Visible light communication(VLC) network over optical fiber has become a potential candidate in ultra-high speed indoor wireless communication. To mitigate signal distortion accumulated in optical fiber and VLC channel, we present to utilize support vector machine(SVm) for constellation classification in two kinds of geometrically-shaped 8 QAm(quadrature amplitude modulation) seamless integrated fiber and VLC system. We introduce 4 sub-bands to simulate multi-user. Experimental results show that system performance can be significantly improved, and transmission at-2.5 dB m input optical power under 7%forward error correction(FEC) threshold can be realized employing Circular(7, 1) geometrically-shaped8 QAm and SVm. At overall capacity of 960 mbps, Q-factor increases by up to 11.5 dB.

关键词： visible light communication VLC support vector machine SVm geometrically shaping GS VLC network constellation classification

A novel benzo[4,5]furo[3,2-d]pyrimidine-based host as a n-type host for blue phosphorescent organic light-emitting diodes

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Science China materials 2022年第4期65卷 1028-1033页

作者： Junsu ha Junseop Lim Jun Yeob Lee School of Chemical Engineering Sungkyunkwan University2066Seobu-roJangan-guSuwon-siGyeonggi-do16419Republic of Korea

An electron-transport-type host was synthesized using a benzo[4,5]furo[3,2-d]pyrimidine(BFP)core to develop a high triplet energy *** host was designed to have both the tetraphenylsilyl blocking group and the hole-transport-type carbazole *** the device application,the host was used as an electron-transport-type host mixed with a hole-transport-type 3,3'-di(9H-carbazol-9-yl)-1,1†-biphenyl(mCBP)host in the blue phosphorescent organic light-emitting diodes(PhO-LEDs)doped with a[[5-(1,1-dimethylethyl)-3-phenyl-1H-imidazo[4,5-b]pyrazin-1-yl-2(3H)-ylidene]-1,2-phenylene]bis-[[6-(1,1-dimethylethyl)-3-phenyl-1H-imidazo[4,5-b]pyrazin-1-yl-2(3H)-ylidene]-1,2-phenylene]iridium(Ir(cb)3)blue *** a result,the mCBP:CzBFPmSi mixed host showed high external quantum efficiency over 20%at 1000 cd m^(−2) and low efficiency roll-off in the blue PhOLEDs.

关键词： blue device host efficiency lifetime

Low-temperature synthesis of Fe_(2)(moO_(4))_(3) nanosheets: A cathode for sodium ion batteries with kinetics enhancement

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Nano Research 2021年第11期14卷 3977-3987页

作者： ha Tran Huu N.S.m.Viswanath Ngoc Hung Vu Jong-Won Lee Won Bin Im Division of materials Science and Engineering Hanyang University222Wangsimni-roSeongdong-guSeoul04763Republic of Korea School of materials Science and Engineering Chonnam National University77 Yongbong-roBuk-guGwangju61186Republic of Korea Falcuty of Biotechnology Chemistry and Environmental EngineeringPhenikaa UniversityHanoi10000Vietnam A&A Green Phoenix Group Phenikaa Research and Technology Institute(PRATI)167 Hoang NganHanoi10000Vietnam Department of Energy Science and Engineering Daegu Gyeongbuk Institute of Science and Technology(DGIST)333 Techno Jungang-daeroHyeonpung-eupDalseonggunDaegu42988Republic of Korea

Sodium ion batteries (SIBs) are alternatives to lithium ion batteries (LIBs), and offer some significant benefits such as cost reduction and a lower environmental impact;however, to compete with LIBs, further research is required to improve the performance of SIBs. In this study, an orthorhombic Na super ionic conductor structural Fe_(2)(moO_(4))_(3) nanosheet with amorphous-crystalline core-shell alignment was synthesized using a facile low-temperature water-vapor-assisted solid-state reaction and applied as a cathode material for SIBs. The obtained material has a well-defined three-dimensional stacking structure, and exhibits a high specific capacity of 87.8 mAh·g^(−1) at a current density of 1 C = 91 mA·g^(−1) after 1,000 cycles, which is due to the considerable contribution of extra surface-related reaction such as the pseudo-capacitive process. This material shows significantly improved cycling and rated behavior as well as enhanced performance under high- and low-temperature conditions, as compared to the same materials prepared by the conventional high-temperature solid-state reaction. This enhancement is explained by the unique morphology in combination with the improved kinetics of the electrochemical reaction due to its lower charge transfer resistance and higher sodium ion conductivity.

关键词： low-temperature synthesis cathode sodium ion batteries kinetics Na+super ionic conductor(NASICON)

Bifurcation Analysis of the Voltage Controlled Photosensitive Chaotic Oscillator

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Chinese Physics Letters 2013年第6期30卷 42-45页

作者： Van ha Nguyen han Jung Song Department of Nano Systems Engineering Inje UniversityGimhae 621-749Korea Center for Nano manufacturing Inje UniversityGimhae 621-749Korea

A photosensitive chaotic oscillator which can be controlled with light illumination under various control voltage levels is *** oscillator consists of a photodiode for the light input,clock switches and capacitors for the sample and hold function,a nonlinear function that creates an adjustable chaos map,and a voltage shifter that adjusts the output voltage for *** optimizing the photodiode sub-circuit by using an available photodiode model in PC-based simulation program with integrated circuit emphasis to obtain a suitable output,the full chaotic circuit is verified with standard 0.6-μm complementary metal oxide semiconductor *** dynamics are analyzed as a function of the light intensity under different control voltage *** time series,frequency spectra,transitions in state spaces,bifurcation diagrams and the largest Lyapunov exponent are improved.

关键词： oscillator chaotic function

A Remark on Strong Law of Large Numbers for Weighted U-Statistics

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Acta mathematica Sinica,English Series 2014年第9期30卷 1595-1605页

作者： Hyung-Tae ha mei Ling HUANG Department of Applied Statistics Gachon University Department of mathematics and Statistics Brock University

Let （X, Xn; n≥ 1} be a sequence of i.i.d, random variables with values in a measurable space （S,8） such that E｜h（X1, X2,..., Xm）｜〈 ∞, where h is a measurable symmetric function from Sm into R = （-∞, ∞）. Let {wn,i1,i2 im ; 1 ≤ i1 〈 i2 〈 …… 〈im 〈 n, n ≥ m} be a matrix array of real numbers. motivated by a result of Choi and Sung （1987）, in this note we are concerned with establishing a strong law of large numbers for weighted U-statistics with kernel h of degree m. We show that whenever SUP n≥m max1〈i1〈i2〈…〈im≤｜wn i1,i2 i,im｜〈∞, where 0 = Eh（X1, X2,..., Xm）. The proof of this result is based on a new general result on complete convergence, which is a fundamental tool, for array of real-valued random variables under some mild conditions.

关键词： Strong law of large numbers weighted U-statistics complete convergence

Anti TB drug resistance in Tanga,Tanzania:a cross sectional facility base prevalence among pulmonary TB patients

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Asian Pacific Journal of Tropical medicine 2015年第11期8卷 887-893页

作者： ha Abubakar S.Hoza Sayoki G.m.mfinanga Brigitte Knig Department of medical microbiology & Epidemiology of Infectious Diseases Medical FacultyUniversity of Leipzig Department of microbiology & Parasitology.Sokoine University of Agriculture National Institute for medical Research(NImR)

Objective:To determine the prevalence and risk factors associated with drug resistance tuberculosis(TB) at facility-base level in Tanga,***:A total of 79 mycobacterium tuberculosis(mTB) isolates included in the study were collected from among372(312 new and 60 previously treated) TB suspects self referred to four TB clinics during a prospective study conducted from November 2012 to January *** and drug susceptibility test of the isolates was performed at the institute of medical microbiology and epidemiology of infectious diseases,University hospital,Leipzig,*** on the patient's characteristics were obtained from structured questionnaire administered to the patients who gave informed verbal *** bivariate logistic regression analysis was performed to assess the risk factors for drug *** significance level was determined at PmDRTB were 12.7%and 6.3%*** prevalence of any drug resistance and mDRTB among new cases were 11.4%and 4.3%respectively,whereas among previously treated cases was 22.2%*** treated patients were more likely to develop anti-TB drug *** was no association between anti-TB drug resistances(including mDRTB) with the risk factors ***:High proportions of anti TB drug resistance among new and previously treated cases observed in this study suggest that,additional efforts still need to be done in identifying individual cases at facility base level for improved TB control programmes and drug resistance survey should continuously be monitored in the country.

关键词： Pulmonary tuberculosis Prevalence Drug resistance

Natural Convection of a Power-Law Nanofluid in a Square Cavity with a Vertical Fin

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Fluid Dynamics & materials Processing 2024年第9期20卷 2091-2108页

作者： Amira m’hadbi mohammed El Ganaoui haïkel Ben hamed Amenallah Guizani Khalid Chtaibi LERmAB Department of Transition and Energy Efficiency ProfessionsIUT H Poincaréde LongwyUniversity of LorraineLongwy54400France LPT Center for Energy Research and Technologies(Borj Cedria2084)University of Tunis El ManarTunis1068Tunisia LTI Department of Mechanical Engineering and ProductionIUTUniversity of Picardie Jules-VerneAmiens80025France

The behavior of non-Newtonian power-law nanofluids under free convection heat transfer conditions in a cooled square enclosure equipped with a heated fin is investigated *** particular,the impact of nanofluids,composed of water and Al_(2)O_(3),TiO_(2),and Cu nanoparticles,on heat transfer enhancement is *** aim of this research is also to analyze the influence of different parameters,including the Rayleigh number(Ra=10^(4)-10^(6)),nanoparticle volume fraction(φ=0%-20%),non-Newtonian power-law indexes(n=0.6-1.4),and fin dimensions(Ar=0.3,0.5,and 0.7).Streamlines and isotherms are used to depict flow and related heat transfer *** indicate that thermal performance improves with increasing Rayleigh number,regardless of the nanoparticle type or nanofluid rheological *** suggests that the buoyancy force has a significant impact on heat transfer,particularly near the heat *** Nusselt number is more sensitive to variations in Cu nanoparticle volume fractions compared to Al₂O₃and TiO₂.moreover,the average Nusselt numbers for power-law nanofluids with n1)are greater(smaller)than for Newtonian fluids due to the decrease(increase)in viscosity with increasing(decreasing)shear rate,at the same values of Rayleigh number Ra owing to the amplification(attenuation)of the convective ***,the most substantial enhancement is observed with Cu-water shear-thinning nanofluid,where the Nusselt number increases by 136%when changing from Newtonian to shear thinning behavior and by 154.9%when adding 16%nanoparticle volume ***,an even larger increase of 57%in the average Nusselt number is obtained on increasing the fin length from 0.3 to 0.7.

关键词： Heat transfer nanofluid non-Newtonian fluid natural convection

Investigation of Punch Resistance of the Allomyrira dichtoloma Beetle Forewing

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Journal of Bionic Engineering 2018年第1期15卷 57-68页

作者： Ngoc San ha Vinh Tung Le Nam Seo Goo Smart microsystem Research Laboratory Department of Advanced Technology Fusion Division of Interdisciplinary Studies Konkuk University Seou105029 Republic of Korea Faculty of Science Engineering and Technology Swinburne University of Technology Hawthorn VIC 3122 Australia

In this study, the punch resistance of the beetle forewing was investigated to address the ability of the forewing against the external force. The punch resistance of the forewing was measured for different sizes and sexes of beetles using a conventional testing method in conjunction with the Digital Image Correlation （DIC） technique. The results showed that the maximum fracture load was measured around 23 N for the female beetle and around 20.2 N for the male beetle in the front-side punch test. moreover, the fracture load in the front-side punch test was higher than that in the back-side punch test for both male and female beetles. This means that the beetle forewing plays a protection role against external loads. Furthermore, the puncture energy in the front-side punch test for the female beetle （6.91 m J） was a little higher than that for the male beetle （5.27 mJ）. In addition, the DIC results revealed that the first crack occurred along the trachea line and the second crack then appeared in the direction that was perpendicular to the direction of the first crack. This study provides a com- prehensive understanding of the mechanical protection properties of the beetle forewing and offers a good lesson for studying lightweight bio-inspired composite material.

关键词： beetle forewing punch test punch energy digital image correlation