检索结果-南通市图书馆

Evaluation of the viability of nanoparticles in drilling fluids as additive for fluid loss and wellbore stability

在线全文

学校读者我要写书评

暂无评论

Petroleum 2023年第3期9卷 342-351页

作者： albertus Retnanto Rommel Yrac Abdullah Shaat Adhika Retnanto Laith Abughaush m.ha al sulaiti Najla Badar Texas A&m University at Qatar Qatar Georgia Institute of Technology USA

Wellbore instability is an issue that,if left untreated,can cause wells to collapse,resulting in human,environmental,equipment,and revenue *** fluids have been used to enhance the drilling process by lubricating and cooling the drill bit,eliminating cuttings,and most importantly,by improving the stability of the well by preventing fluid ***,there has been an increase in operational demands and challenges that call for drilling fluids to be more effective,economical,sustainable,and environmentally *** shales that have infinitesimally small pores,nanoparticle additives in drilling fluids can be crucial in providing the properties that are necessary to prevent fluid loss and provide wellbore stability while meeting the operational demands of the present ***,this paper examines the use of nanoparticle additives including copper(Ⅱ)oxide(CuO),magnesium oxide(mgO),and aluminum oxide(al_(2)O_(3))where they are tested under three conditions using the permeable plugging tester(PPT),high-temperature high-pressure(HTHP)fluid loss apparatus,and API low-temperature e low-pressure(LTLP)fluid loss apparatus under concentrations of 0.03%and 0.10%.Finally,based on the results,each nanoparticle sample(particle sizes between one and 100 nm)performed well in contributing to the aim of this *** is the most effective inhibitor across all concentrations and under the three different *** contributed to reducing the fluid loss from 37.6 mL to 18.2 and 13.2 mL,which is between 52%and 65%of fluid *** mgO,it contributed to fluid loss reduction to 23.8 mL and 15 mL,which translated to 37%e60%of fluid loss *** use of al_(2)O_(3) nanoparticles resulted in a fluid loss reduction to 33.6 mL and 17.8 mL,reducing the fluid loss up to 11%,at HTHP and up to 53%at *** CuO and mgO,al_(2)O_(3) was less effective under HTHP conditions when compared to LTLP ***_(2)O_(3) did not suffer as a significant diminishing

关键词： Nanoparticles Drilling fluids Additives Fluid loss High-temperature and high-pressure

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

在线全文

学校读者我要写书评

暂无评论

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)

maize response to elevated plant density combined with lowered N-fertilizer rate is genotype-dependent

在线全文

学校读者我要写书评

暂无评论

The Crop Journal 2015年第2期3卷 96-109页

作者： Ahmed medhat m.al-Naggar Reda A.Shabana m.hamed m.m.Atta Tarek H.al-Khalil Agronomy Department Faculty of Agriculture Cairo University

Increasing plant density and improving N fertilizer rate along with the use of high density-tolerant genotypes would lead to maximizing maize(Zea mays L.) grain productivity per unit land area. The objective of this investigation was to match the functions of optimum plant density and adequate nitrogen fertilizer application to produce the highest possible yields per unit area with the greatest maize genotype efficiency. Six maize inbred lines differing in tolerance to low N and high density(D) [three tolerant(T); L-17, L-18, L-53,and three sensitive(S); L-29, L-54, L-55] were chosen for diallel crosses. Parents and crosses were evaluated in the 2012 and 2013 seasons under three plant densities: low(47,600),medium(71,400), and high(95,200) plants ha-1and three N fertilization rates: low(no N addition), medium(285 kg N ha-1) and high(570 kg N ha-1). The T × T crosses were superior to the S × S and T × S crosses under the low N–high D environment in most studied traits across seasons. The relationships between the nine environments and grain yield per hectare(GYPH) showed near-linear regression functions for inbreds L54, L29, and L55 and hybrids L18 × L53 and L18 × L55 with the highest GYPH at a density of47,600 plants ha-1and N rate of 570 kg N ha-1and a curvilinear relationship for inbreds L17, L18, and L53 and the rest of the hybrids with the highest GYPH at a density of95,200 plants ha-1combined with an N rate of 570 kg N ha-1. Cross L17 × L54 gave the highest grain yield in this study under both high N–high-D(19.9 t ha-1) and medium N–high-D environments(17.6 t ha-1).

关键词： Quadratic regression Appropriate N rate High-density tolerant maize Unit area productivity

Impacts of Heat Flux Distribution, Sloping magnetic Field and magnetic Nanoparticles on the Natural Convective Flow Contained in a Square Cavity

在线全文

学校读者我要写书评

暂无评论

Fluid Dynamics & materials Processing 2020年第3期16卷 441-463页

作者： Latifa m.al-Balushi m.m.Rahman Department of mathematics College of ScienceSultan Qaboos UniversityMuscatOman

In the present paper,the effect of the heat flux distribution on the natural convective flow inside a square cavity in the presence of a sloping magnetic field and magnetic nanoparticles is explored *** nondimensional governing equations are solved in the framework of a finite element method implemented using the Galerkin *** role played by numerous model parameters in influencing the emerging thermal and concentration fields is examined;among them are:the location of the heat source and its lengthH,the magnitude of the thermal Rayleigh number,the nanoparticles shape and volume fraction,and the hartmann *** is found that the nanofluid velocity becomes higher when the thermal source length,the nanoparticles volume fraction and/or the thermal Rayleigh number are increased,while it decreases as the hartmann number ha grows and the position of the heat source moves toward the center of the lower wall of the ***,the temperature of the nanofluid grows with the extension of the thermal source and decreases slowly when the heat flux position moves toward the center of the lower *** outcomes of the research also indicate that the average Nusselt number becomes smaller on increasing hartmann number ha and heat source length H^(*).The addition of Fe_(3)O_(4) to engine oil leads to a higher rate of heat transfer with respect to the addition of SiO_(2) ***-shaped nanoparticles generate the highest value of the Nusselt number compared to all the other considered shapes.

关键词： Nanofluids magnetic nanoparticles heat source natural convection finite element method square enclosure

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

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

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

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

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

在线全文

学校读者我要写书评

暂无评论

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

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

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 em.hasis 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

在线全文

学校读者我要写书评

暂无评论

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