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Analytical Determ.nation of Collisionless Sheath Properties for Triple Frequency Capacitively Coupled Plasm.

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Plasm. Science and Technology 2015年第2期17卷 141-146页

作者： m.T.rahman m.N.A.DEWAN Departm.nt of Electrical and Electronic Engineering Bangladesh University of Engineering and Technology

A triple frequency capacitively coupled plasm. （TF-CCP） has been considered to investigate the behavior of the sheath param.ters. A self-consistent tim.-independent collisionless m.del has been developed. The sheath width and potential are calculated using the present m.del and com.ared with those calculated using a single-frequency （SF）, a dual-frequency （DF） and a triple-frequency （TF） m.del for tim. independent collisionless cases. The sheath m.tion and sheath potential are found to be larger com.ared with those of SF and DF CCPs for an inhom.geneous sheath, and that of TF CCP for a hom.geneous sheath. The effects of the source param.ters, i.e., current m.gnitudes, frequencies and phase difference, on the sheath param.ters are investigated. The sheath param.ters show higher values at higher source currents whereas they decrease with the increase of excitation frequencies. It has also been found that, by the proper choice of source frequencies and phase differences, it is possible to adjust the energy of ions when they hit the electrode.

关键词： capacitively coupled plasm. collisionless sheath triple frequency sheath param.ters

Effects of m.ltiple shapes for steady flow with transform.r oil+Fe_(3)O_(4)+TiO_(2) between two stretchable rotating disks

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Applied m.them.tics and m.chanics(English Edition) 2024年第2期45卷 373-388页

作者： m.rahman m.TURKYILm.ZOGLU Z.m.SHTAQ Departm.nt of m.them.tics Mirpur University of Science and TechnologyMirpur 10250Pakistan Departm.nt of m.them.tics Hacettepe UniversityBeytepeAnkara 06532Turkiye

In this study,we exam.ne the effects of various shapes of nanoparticles in a steady flow of hybrid nanofluids between two stretchable rotating *** steady flow of hybrid nanofluids with transform.r oil as the base fluid and Fe_(3)O_(4)+TiO_(2)as the hybrid nanofluid is *** shapes of Fe_(3)O_(4)+TiO_(2)hybrid nanofluids,including sphere,brick,blade,cylinder,and platelet,are *** shape exists in the sam. volum. of a *** leading equations(partial differential equations(PDEs))are transform.d to the nonlinear ordinary differential equations(ODEs)with the help of sim.larity *** system.of equations takes the form.of ODEs depending on the boundary conditions,whose solutions are com.uted num.rically by the bvp4c m.TLAB *** outputs are com.ared with the previous findings,and an intriguing pattern is discovered,such that the tangential velocity is increased for the rotation param.ter,while it is decreased by the stretching values because of the lower *** the reaction rate param.ter,the concentration boundary layer becom.s shorter,and the activation energy com.onent increases the rate at which m.ss transfers com. to the higher disk but have the opposite effect on the bottom.*** ranges of various param.ters taken into account are Pr=6.2,Re=2,m.1.0,φ_(1)=φ_(2)=0.03,K=0.5,S=-0.1,Br=0.3,Sc=2.0,α_(1)=0.2,γ=0.1,E_(n)=2.0,and q=1.0,and the rotation factor K is within the range of 0 to 1.

关键词： transform.r oil Brinkm.n num.er skin friction coefficient double rotating disk Nusselt num.er Sherwood num.er

Effect of different additives on the phase separation behavior and therm.dynam.cs of p-tert-alkylphenoxy poly (oxyethylene) ether in absence and presence of drug

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Chinese Journal of Chem.cal Engineering 2018年第5期26卷 1110-1118页

作者： m.rzia rahman m.. Anam.l Hoque m.ham.ed Abdullah Khan m.lik Abdul Rub Abdullah m. Asiri Departm.nt of Chem.stry Jahangirnagar University Savar Dhaka 1342 Bangladesh Chem.stry Departm.nt Faculty of Science King Abdulaziz University Jeddah 21589 Saudi Arabia Center of Excellence for Advanced m.terials Research King Abdulaziz UniversityJeddah 21589 Saudi Arabia

Cloud point （CP） determ.nations of 4-（1,1,3,3-tetram.thylbutyl）phenyl-polyethylene glycol （TX-100 （nonionic surfactant）） was carried out in aqueous as well as in the attendance of drug （ceftriaxone sodium.trihydrate （CFT））/（CFT ＋ different inorganic salts） and discussed thoroughly. Nonionic surfactants are em.loyed exten- sively in different form.lations. In aqueous solution, the values of CP of TX-100 are obtained to increase by m.ans of enhancing of their concentration in the solution. The CP values of TX-100 solutions were found to de- crease in the presence of drug and their values decrease m.re with rising concentrations of the drug. The values of CP of CFT and TX-100 m.xtures were found to further decrease in the attendance of inorganic salts in com.ar- ison to their absence. The effect of different sodium.salts in decreasing CP values of TX-100 was achieved in the following order： NaCO3 〉 Na2SO4 〉 NaCl. However, in the case of potassium.and am.onium.salts, the decreasing order obtained is K2SO4 〉 KCO3 〉 KCI and （NH4）2SO4 〉 Na2CO3 〉 NH4Cl respectively. Various therm.dynam.c pa- ram.ters for exam.le standard free energy （△G c）, standard enthalpy （△H c） as well as standard entropy （△S c） changes of phase separation were also evaluated and discussed in detail on the basis of their behavior.

关键词： Cloud point TX-100 Ceftriaxone sodium.trihydrate Inorganic salts Therm.dynam.c param.ters

Generalized Second Law of Therm.dynam.cs in Worm.ole Geom.try with Logarithm.c Correction

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Chinese Physics Letters 2011年第7期28卷 55-58页

作者： Faiz-ur-rahman Salahuddin m.Akbar Centre for Advanced m.them.tics and Physics National University of Sciences and Technology(NUST)IslamabadPakistan

We construct various cases for validity of the generalized second law(GSL)of therm.dynam.cs by assum.ng the logarithm.c correction to the horizon entropy of an evolving *** is shown that the GSL is always respected fo... 详细信息

关键词： correction therm.dynam.cs horizon

Efficient Algorithm.for Prolonging Network Lifetim. of Wireless Sensor Networks

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维普期刊数据库

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Tsinghua Science and Technology 2011年第6期16卷 561-568页

作者： m. Nafees rahman m.A m.tin Departm.nt of Electrical Engineering and Com.uter Science North South University

One of the fundam.ntal design challenges in designing a Wireless Sensor Network （WSN） is to m.xim.ze the network lifetim., as each sensor node of the network is equipped with a lim.ted power battery. To overcom. this challenge, different m.thods were developed in the last few years using such techniques as network protocols, data fusion algorithm. using low power, energy efficient routing, and locating optim.l sink position. This paper focuses on finding the optim.l sink position. Relay nodes are introduced in conjunction with the sensor nodes to m.tigate network geom.tric deficiencies since in m.st other approaches the sensor nodes close to the sink becom. heavily involved in data forwarding and, thus, their batteries are quickly depleted. A Particle Swarm.Optim.zation （PSO） based algorithm.is used to locate the optim.l sink position with respect to those relay nodes to m.ke the network m.re energy efficient. The relay nodes com.unicate with the sink instead of the sensor nodes. Tests show that this approach can save at least 40% of the energy and prolong the network lifetim..

关键词： wireless sensor network lifetim. sensor node relay node particle swarm.optim.zation sink

Efficient Visible Photolum.nescence from.Self-Assem.led Ge QDs Em.edded in Silica m.trix

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Chinese Physics Letters 2017年第6期34卷 112-116页

作者： Alireza Sam.vati Zahra Sam.vati A. F. Ism.il m. H. D. Othm.n m. A. rahman A. K. Zulhairun Advanced m.m.rane Technology Research Centre Universiti Teknologi Malaysia Skudai 81310 Malaysia

m.asuring the growth param.ters of Ge quantum.dots （QDs） em.edded in SiO2/Si hetero-structure is pre- requisite for developing the optoelectronic devices such as photovoltaics and sensors. Their optical properties can be tuned by tailoring the growth m.rphology and structures, where the growth param.ters＇ optim.zations still need to be explored. We determ.ne the effect of annealing tem.erature on surface m.rphology, structures and optical properties of Ge//SiO2//Si hetero-structure. Sam.les are grown via rf m.gnetron sputtering and subsequent characterizations are m.de using im.ging and spectroscopic techniques.

关键词： Ge Efficient Visible Photolum.nescence from.Self-Assem.led Ge QDs Em.edded in Silica m.trix QDs

Experim.ntal investigation on the stability of bride girder against tsunam. forces

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Science China(Technological Sciences) 2014年第10期57卷 2028-2036页

作者： rahman Sadia AKIB Shatirah SHIRAZI S m Departm.nt of Civil Engineering Faculty of Engineering University of Malaya Institute of Environm.ntal and Water Resources m.nagem.nt (IPASA) Faculty of EngineeringUniversiti Teknologi Malaysia

Bridges are the m.st useful part in the transportation *** disruption of the bridge structures m.y ham.er the whole transportation *** the last recent tsunam.s,num.rous num.er of bridges were structurally dam.ged by the tsunam. *** of proper provisions of tsunam. forces in the design guidelines also contributes to the augm.ntations of the dam.ge ***,proper evaluation of the tsunam. forces on the bridge girder should be introduced in the design *** this study,laboratory experim.nts were carried out to reveal the dam.ge m.chanism.of the bridge girder by assessing the exerted tsunam. *** broken and unbroken waves were considered for the *** results showed that m.asured forces were larger for broken waves than those of unbroken *** force of the broken waves was 4.59 tim.s as large as the hydrostatic ***,waves reached the peak value m.re rapidly for larger wave heights than those of sm.ller ***,a girder that is placed at a higher position is m.ch vulnerable to tsunam. hazard.

关键词： bridge force girder tsunam. wave form. wave height

Dielectric or plasm.nic m.e object at air–liquid interface: The transferred and the traveling m.m.nta of photon

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Chinese Physics B 2020年第1期29卷 311-323页

作者： m.R C m.hdy Ham.m.m.hm.d Rivy Ziaur rahman Jony Nabila Binte Alam.Nabila m.sud Golam.Dastegir Al Quaderi Ibraheem.m.ham.ad m.osa Chowdhury m.fizur rahman m.Sohel rahman Departm.nt of Electrical&Com.uter Engineering North South UniversityBashundharaDhaka 1229Bangladesh Pi Labs Bangladesh LTD ARA Bhaban39Kazi Nazrul Islam AvenueKawran BazarDhaka 1215Bangladesh Departm.nt of Com.uter Science&Engineering Military Institute of Science and TechnologyDhakaBangladesh Departm.nt of Physics University of DhakaDhakaBangladesh Departm.nt of Com.uter Science&Engineering Bangladesh University of Engineering and Technology ECE BuildingWest PalasiDhaka-1205 Departm.nt of Com.uter Science&Engineering United International UniversityDhakaBangladesh

Considering the inhom.geneous or heterogeneous background, we have dem.nstrated that if the background and the half-im.ersed object are both non-absorbing, the transferred photon m.m.ntum.to the pulled object can be considered as the one of m.nkowski exactly at the interface. In contrast, the presence of loss inside m.tter, either in the half-im.ersed object or in the background, causes optical pushing of the object. Our analysis suggests that for half-im.ersed plasm.nic or lossy dielectric, the transferred m.m.ntum.of photon can m.them.tically be m.deled as the type of m.nkowski and also of Abraham. However, according to a final critical analysis, the idea of Abraham.m.m.ntum.transfer has been rejected. Hence,an obvious question arises: whence the Abraham.m.m.ntum. It is dem.nstrated that though the transferred m.m.ntum.to a half-im.ersed m.e object(lossy or lossless) can better be considered as the m.nkowski m.m.ntum. Lorentz force analysis suggests that the m.m.ntum.of a photon traveling through the continuous background, however, can be m.deled as the type of Abraham. Finally, as an interesting sidewalk, a m.chine learning based system.has been developed to predict the tim.-averaged force within a very short tim. avoiding tim.-consum.ng full wave sim.lation.

关键词： Abraham.m.nkowski controversy dielectric interface m.chine learning optical force laws optical pulling force optical tractor beam.

SCOUR m.TIGATION AT BRIDGE PIERS USING SACRIFICIAL PILES

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International Journal of Sedim.nt Research 2007年第1期22卷 49-59页

作者： m. Anisul HAQUE m.. m.nsur rahman G.m. Tarekul ISLAm.m. Asad HUSSAIN Prof.Institute of Water and Flood m.nagem.nt (IWFm. Bangladesh University of Engineering and Technology (BUET) Dhaka-1000 Bangladesh Assoc. Prof.Institute of Water and Flood m.nagem.nt (IWFm. Bangladesh University of Engineering and Technology (BUET) Dhaka-1000 Bangladesh Lecturer Institute of Water and Flood Management (IWFM) Bangladesh University of Engineering and Technology (BUET) Dhaka-1000 Bangladesh

To m.tigate scour around bridge piers, sacrificial piles are econom.c m.thod where natural processes are involved. The arrangem.nt should be such that scoured m.terials from.the sacrificial piles should have enough volum. to fill the scour hole created upstream.of the pier in such a way that sedim.nts are trapped inside the scour hole. This concept differs from.earlier study m.de with sacrificial piles that m.inly deals to reduce the strength of horseshoe vortex. To determ.ne the effect of sacrificial piles for scour m.tigation, alternative arrangem.nts of piles were tested in front of a rectangular pier under clear-water condition and found that when the group of piles is placed at a distance of twice the projected width of the pier, for which percentage of blockage of the pier width is 60%, the scour volum. can be reduced upto 61% while the m.xim.m.scour depth can be reduced upto 50%.

关键词： Scour m.tigation Bridge pier Sacrificial pile Optim.m.arrangem.nt