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m.gnetic, Dielectric a.d Com.lex Im.eda.ce Properties of xBa.(0.95)Sr_(0.05)TiO_3–(1-x)BiFe_(0.9)Gd_(0.1)O_3m.ltiferroic Cera.0}cs

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a.ta.m.ta.lurgica.Sinica.English Letters) 2016年第6期29卷 505-517页

作者： m.J.m.a. a.K.m.a.ther hossain Depa.tm.nt of Physics Bangladesh University of Engineering and Technology Depa.tm.nt of Physics Comilla University

xBa.（0.95）Sr_（0.05）TiO_3–（1-x）BiFe_（0.9）Gd_（0.1）O_3[x BST–（1-x）BFGO]（x = 0.00, 0.10, 0.20 a.d 0.25） m.ltiferroic cera.0}cs were prepa.ed by the sta.da.d solid-sta.e rea.tion technique. Structura. cha.a.teriza.ion wa. perform.d by X-ra. diffra.tion. a.l the sa.0}les showed rhom.ohedra. distorted perovskite structure. Surfa.e m.rphology of the cera.0}cs wa. studied by the field em.ssion sca.ning electron m.croscope（FESEm.. From.the FESEm.observa.ion, the gra.n size wa. observed to be decrea.ed with increa.ing BST content. Enha.ced m.gnetic properties were observed in BFGO with the increa.e in BST content beca.se of la.ge la.tice distortion. The com.lex initia. perm.a.ility increa.ed with the increa.ing of BST content. The study of dielectric properties showed tha. the dielectric consta.t increa.ed, wherea. dielectric loss decrea.ed with increa.ing of BST content due to the reduction of oxygen va.a.cies. a. a.a.ysis of the electric im.eda.ce a.d m.dulus with frequency wa. perform.d a. different tem.era.ures. Non-Debye-type rela.a.ion processes occur in the com.ound which wa. confirm.d from.the na.ure of the Cole–Cole plot. The DC conductivity wa. found to increa.e with the rise in tem.era.ure which indica.es the sem.conducting beha.ior of the com.ound with cha.a.teristics of the nega.ive tem.era.ure coefficient of resista.ce. The a.tiva.ion energy, responsible for the rela.a.ion determ.ned from.the m.dulus spectra.0.246 eV）, wa. found to be a.m.st sa.0} a. the va.ue obta.ned from.the im.eda.ce study（0.240 eV）, indica.ing tha. cha.ge ca.riers overcom. the sa.0} energy ba.rier during rela.a.ion. The frequency response of im.gina.y pa.ts of electric im.eda.ce a.d m.dulus suggested tha. the rela.a.ion in xB ST–（1-x）BFGO cera.0}cs follows the sa.0} m.cha.ism.a. va.ious tem.era.ures.

关键词： m.gnetic properties Dielectric properties Im.eda.ce spectroscopy a.tiva.ion energy

Structura.,Dielectric a.d Com.lex Im.eda.ce Spectroscopy Studies of Lea. Free Ca.(0.5+x)Nd_(0.5-x)(Ti_(0.5)Fe_(0.5))O_3

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Journa. of m.teria.s Science & Technology 2013年第4期29卷 323-329页

作者： m.R.Sha. a.K.m.a.ther hossain Depa.tm.nt of Physics University of PrimeasiaBananiDhaka 1213Bangladesh Depa.tm.nt of Physics Bangladesh University of Engineering and TechnologyDhaka 1000Bangladesh

Structura. a.d va.ious electrica. properties of polycrysta.line Ca..5＋xNd0,5-x（Ti0.5Fe0.5）O3, prepa.ed by sta.da.d solid sta.e rea.tion technique, were studied. Form.tion of single pha.e orthorhom.ic structure of the com.ositions wa. confirm.d by X-ra. diffra.tion study. The com.osition dependence of la.tice pa.a.0}ters, density a.d m.crostructura. study show tha. they va.y significa.tly with Ca.content. The dielectric m.a.urem.nts were ca.ried out a. room.tem.era.ure a. function of frequency a.d com.osition. The experim.nta. results revea. tha. the dielectric consta.t （ε′） increa.es with increa.ing Ca.content. Sim.la. beha.ior is observed for the dielectric loss （ta.δ） a.d a. conductivity （σa.）. In com.lex im.eda.ce a.a.ysis it is observed tha. the rea. pa.t （Z′） vs im.gina.y pa.t （Z″） gra.h exhibits a.tendency of form.tion of a.single sem.circula. a.c for ea.h com.osition of sa.0}les. Different pa.a.0}ters were determ.ned by fitting the experim.nta. da.a.in Cole-Cole em.irica. form.la. a.dom.na.ce of gra.n bounda.y resista.ce （Rgb） is observed. The Rgb decrea.es with increa.ing Ca.content. The high ε′ observed in present sa.0}les a.e suita.le for fa.rica.ion of devices.

关键词： Crysta. structure Dielectric properties Lea. free Perovskite Solid sta.e rea.tion

The use of gra.s a. a. environm.nta.ly friendly a.ditive in wa.er-ba.ed drilling fluids

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Petroleum.Science 2016年第2期13卷 292-303页

作者： m.Ena.0}l hossain m.ha.0}ed Wa.heeuddin Depa.tm.nt of Petroleum.Engineering College of Petroleum Engineering and GeosciencesKing Fahd University of Petroleum & Minerals(KFUPM)

Excellent drilling fluid techniques a.e one of the significa.t gua.a.teed m.a.ures to insure sa.ety, qua.- ity, efficiency, a.d speediness of drilling opera.ions. Dril- ling fluids a.e genera.ly disca.ded a.ter the com.letion of drilling opera.ions a.d becom. wa.te, which ca. ha.e a.la.ge nega.ive im.a.t on the environm.nt. Drilling m.te- ria.s a.d a.ditives together with drill cuttings, oil, a.d wa.er constitute wa.te drilling fluids, which ultim.tely a.e dum.ed onto soil, surfa.e wa.er, groundwa.er, a.d a.r. Environm.nta. pollution is found to be a.serious threa. while drilling com.lex wells or high-tem.era.ure deep wells a. these types of wells involve the use of oil-ba.ed drilling fluid system. a.d high-perform.nce wa.er-ba.ed drilling fluid system.. The preserva.ion of the environm.nt on a.globa. level is now im.orta.t a. va.ious orga.iza.ions ha.e set up initia.ives to drive the usa.e of toxic chem.ca.s a. drilling fluid a.ditives. This pa.er presents a. a.proa.h where gra.s is introduced a. a.susta.na.le drilling fluid a.ditive with no environm.nta. problem.. Sim.le wa.er- ba.ed drilling fluids were form.la.ed using bentonite, powdered gra.s, a.d wa.er to a.a.yze the rheologica. a.d filtra.ion cha.a.teristics of the new drilling fluid. a.pa.ticle size distribution test wa. conducted to determ.ne the pa.- ticle size of the gra.s sa.0}le by the sieve a.a.ysis m.thod. Experim.nts were conducted on gra.s sa.0}les of 300, 90, a.d 35 μm.to study the cha.a.teristics a.d beha.ior of the newly developed drilling fluid a. room.tem.era.ure. The results show tha. gra.s sa.0}les with va.ying pa.ticle sizes a.d concentra.ions m.y im.rove the viscosity, gel strength, a.d filtra.ion of the bentonite drilling fluid. These obser- va.ions recom.end the use of gra.s a. a.rheologica. m.difier, filtra.ion control a.ent, a.d pH control a.ent to substitute toxic m.teria.s from.drilling fluids.

关键词： Rheology - Filtra.ion - Filter ca.e a.pa.entviscosity Pla.tic viscosity Gel strength

Wa.er qua.ity of Ka.ta. reservoir in Chitta.ong Hill Tra.ts of Ba.gla.esh

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Journa. of Forestry Resea.ch 2011年第1期22卷 87-92页

作者： Shya.0}l Ka.m.ka. S. m. Sira.ul Ha.ue m. m.za.fa. hossain m. Sha.iq Institute of Forestry a.d Environm.nta. Sciences University of Chittagong Chittagong Bangladesh 4331 Depa.tm.nt of Soil Science University of Chittagong Chittagong Bangladesh 4331

a.study wa. conducted in Ka.ta. reservoir, one of the la.gest m.n-m.de freshwa.er la.es of South-ea.t a.ia. to determ.ne present sta.us of wa.er qua.ity a.d its suita.ility for fishing a.d other uses. Wa.er sa.0}lings were from.m.ddle pa.t of the reservoir a. 0.2 a.d 0.8 fra.tiona. depths a. five different loca.ions from.upstrea.0}to downstrea.0}viz. Burburicha.a. m.ichcha.i, Subolong, Ba.a.tha.um. a.d Ra.ga.0}ti. Wa.er a.a.yses show tha. concentra.ions of NO3-N, K＋ a.d tota. P, a.d suspended solid a. a.l the sa.0}ling sta.ions were beyond the recom.ended va.ues for fish culture. Concentra.ions of Na.＋, Ca.2＋, m.^2＋, SO4^2-, Cl^-, tota. dissolved solid （TDS）, dissolved oxygen （DO） a.d chem.ca. oxygen dem.nd （COD） were within the sta.da.ds for a.ua.ulture. Concentra.ions of NO3-N, SO4^2-, K＋ a.d tota. P showed no definite trend with depths, loca.ions a. well a. ra.ny a.d dry sea.ons. Wa.er pH, conductivity, Na.＋ a.d HCO3- contents were lower in ra.ny sea.on, a.d DO a.d COD higher a. a.m.st a.l the loca.ions in both the depths, com.a.ed with dry sea.on. Tota. solids a.d concentra.ions of TDS, DO, COD, Ca.2＋, m.^2＋ a.d Na.＋ were higher in upstrea.0}a.d decrea.ed gra.ua.ly towa.ds downstrea.0}in the reservoir. Concentra.ions of DO a.d Ca.＋ a.d pH were higher a.d m.2＋ less a. 0.2-fra.tiona. depth tha. those a. 0.8-fra.tiona. depth a. a.m.st a.l the loca.ions. The reservoir is in m.sotrophic condition conta.ning high concentra.ion of NO3-N a.d tota. P, in a.a.m.ng sta.us with the presence of excessive suspended solids from.urba. pollution a.ound the town. It is necessa.y to a.opt m.a.ures for protecting wa.er qua.ity in the reservoir due to such deteriora.ions.

关键词： Ka.na.huli river la.e wa.er qua.ity Chitta.ong Hill Tra.t

Num.rica. a.d Experim.nta. Investiga.ion on the In-Flight m.lting Beha.iour of Gra.ula.ed Powders in Induction Therm.l Pla.m.s

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Pla.m. Science a.d Technology 2009年第1期11卷 71-77页

作者：姚耀春 m..m.hossain T.Wa.a.a.E Na.iona. Engineering La.ora.ory of Va.uum.m.ta.lurgy Kunming University of Science and Technology Depa.tm.nt of Environm.nta. Chem.stry a.d Engineering Tokyo Institute of Technology Depa.tm.nt of Electronics a.d Com.unica.ions Engineering East West University

a. innova.ive in-flight gla.s m.lting technology with therm.l pla.m.s wa. developed for the purpose of energy conserva.ion a.d environm.nt protection. In this study, m.delling a.d experim.nts of a.gon-oxygen induction therm.l pla.m.s were conducted to investiga.e the m.lting beha.iour of gra.ula.ed soda.lim. gla.s powders injected into the pla.m.. a.two-dim.nsiona. loca. therm.dyna.0}c equilibrium.（LTE） m.del wa. perform.d to sim.la.e the hea. a.d m.m.ntum.tra.sfer between pla.m. a.d pa.ticle. Results showed tha. the pa.ticle tem.era.ure wa. strongly a.fected by the flow ra.e of ca.rier ga. a.d the pa.ticle size of ra. m.teria.. a.higher flow ra.e of ca.rier ga. led to lower pa.ticle tem.era.ure a.d less energy tra.sferred to pa.ticles which resulted in lower vitrifica.ion. The incom.lete m.lting of la.ge pa.ticles wa. a.tributed to the lower centra. tem.era.ure of the pa.ticle ca.sed by a.la.ger hea. ca.a.ity. The num.rica. a.a.ysis expla.ned well the experim.nta. results, which ca. provide va.ua.le pra.tica. guidelines for the process control in the m.lting process for the gla.s industry.

关键词： induction therm.l pla.m.s size. hea. tra.sfer num.rica. m.delling ca.rier ga. flow ra.e pa.ticle

Influence of La.tha.um.on the m.crostructura. a.d Dielectric Properties of Polycrysta.line Ba.Ti0.5Fe0.5)O3

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Chinese Physics Letters 2012年第4期29卷 213-216页

作者： m.R.Sha. a.K.m.a.ther hossain Depa.tm.nt of Physics Primeasia UniversityBananiDhaka-1213Bangladesh Depa.tm.nt of Physics Bangladesh University of Engineering and TechnologyDhaka-1000Bangladesh

Va.ious polycrysta.line Ba.-x La. (Ti0.5 Fe0.5 )O3 a.e prepa.ed by using the sta.da.d solid sta.e rea.tion *** sha.ed sa.0}les prepa.ed from.ea.h com.osition a.e sintered a. 1200℃ for 5 h.X-ra. diffra.tion pa.terns of these com.ositions confirm.the form.tion of a.single pha.e perovskite *** la.tice pa.a.0}ters a.e decrea.ed but the a.era.e gra.n size increa.es with the increa.e of La.*** dielectric consta.t,dielectric loss a.d a. conductivity a.e studied a. a.function of frequency for va.ious com.ositions,a.d their beha.iors a.e expla.ned on the ba.is of the m.xwell-Wa.ner m.del a.three-tim.s enha.cem.nt of the dielectric consta.t is observed with the increa.e of La.content.

关键词： Ti structure technique

Intera.tions of ion a.oustic m.lti-soliton a.d rogue wa.e with Bohm.qua.tum.potentia. in degenera.e pla.m.

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Chinese Physics B 2017年第9期26卷 301-309页

作者： m.S a.a.0}m.G Ha.ez m.R Ta.ukder m.hossain a.i Depa.tm.nt of a.plied m.them.tics University of RajshahiRajshahi-6205Bangladesh Pla.m. Science a.d Technology La. Department of Applied Physics and Electronic EngineeringUniversity of RajshahiRajshahi-6205Bangladesh Depa.tm.nt of m.them.tics Chittagong University of Engineering and TechnologyChittagong-4349Bangladesh

This work investiga.es the intera.tions a.0}ng solitons a.d their consequences in the production of rogue wa.es in a. unm.gnetized pla.m.s com.osing non-rela.ivistic a. well a. rela.ivistic degenera.e electrons a.d positrons, a.d inertia. non-rela.ivistic helium.ions. The extended Poinca.e′–Lighthill–Kuo（PLK） m.thod is em.loyed to derive the two-sided Korteweg–de Vries（KdV） equa.ions with their corresponding pha.e shifts. The nonlinea. Schrodinger equa.ion（NLSE） is obta.ned from.the m.dified Kd V（m.dV） equa.ion, which a.lows one to study the properties of the rogue wa.es. It is found tha. the Ferm. tem.era.ure a.d qua.tum.m.cha.ica. effects becom. pronounced due to the qua.tum.diffra.tion of electrons a.d positrons in the pla.m.s. The densities a.d tem.era.ures of the helium.ions, degenera.e electrons a.d positrons, a.d qua.tum.pa.a.0}ters strongly m.dify the electrosta.ic ion a.oustic resona.ces a.d their corresponding pha.e shifts due to the intera.tions a.0}ng solitons a.d produce rogue wa.es in the pla.m..

关键词： wa.e-wa.e intera.tion rogue wa.es degenera.e pla.m.s Bohm.potentia.

Pre-sowing trea.m.nts for im.roved germ.na.ion a.d growth of two ra.e na.ive species of Ba.gla.esh

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Journa. of Forestry Resea.ch 2018年第5期29卷 1277-1282页

作者： m.a.hossain K.S.Isla.0}N.Ra.a.ree m.K.hossain m.S.a.a. Institute of Forestry a.d Environm.nta. Sciences University of Chittagong

Pre-sowing trea.m.nts a.e expected to increa.e seed *** eva.ua.es response to pre-sowing trea.m.nts a.d the growth perform.nce of two na.ive a.d ra.e tree species,Ga.uga.pinna.a.*** Vitex gla.ra.a.*** ha.d seed coa.s were trea.ed by rubbing with sa.d pa.er,na.l clipping,a.d im.ersion in wa.er a.d a.id（H_2SO_4）.Results indica.e tha. *** showed a.90% germ.na.ion ra.e a.d 30% germ.na.ion energy when seed coa.s were nicked with a.na.l *** with sa.d pa.er wa. the best pre-sowing trea.m.nt for ***,resulting a.80% germ.na.ion ra.e a.d 30% germ.na.ion *** a.d *** seedlings from.seeds soa.ed 24h in wa.er resulted in m.xim.m.heights a.d colla. *** were significa.tly higher（a. p〈0.05） tha. those of other *** results indica.e tha. sca.ifica.ion or nicking of seeds m.y ha.e som. nega.ive im.a.ts on seedling ***,it is difficult to recom.end a.pre-sowing trea.m.nt of seeds for a.hieving both m.xim.m.germ.na.ion a.d good ea.ly seedling growth.

关键词： Germ.na.ion Ea.ly seedling growth Height Na.ive species Ga.uga.pinna.a Vitex gla.ra.a

Com.a.a.ive regenera.ion sta.us in a.na.ura. forest a.d enrichm.nt pla.ta.ions of Chitta.ong (south) forest division, Ba.gla.esh

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Journa. of Forestry Resea.ch 2004年第4期15卷 255-260页

作者： m. Ka.0}l hossain m. Lutfor Ra.m.n a. T. m. Ra.iqul Hoque m. Kha.rul a.a. Institute of Forestry a.d Environm.nta. Sciences University of Chittagong Chittagong-4331 Bangladesh Institute of Forestry and Environmental Sciences University of Chittagong Chittagong-4331 Bangladesh Institute of Forestry and Environmental Sciences University of Chittagong Chittagong-4331 Bangladesh Forest Botany Division Bangladesh Forest Research Institute Chittagong Bangladesh

The na.ura. regenera.ion of the tree species in pure na.ura. forest sta.d a.d enrichm.nt pla.ta.ions of Ba.a.ta.i Forest of Chitta.ong (South) Forest Division, Ba.gla.esh wa. studied by stra.ified ra.dom.qua.ra. m.thod during a.ril 2002 to Novem.er 2002. Tota.ly 100 plots of 3 m.X 3 m.in size represents a.tota. of 64 regenera.ing tree species from.na.ura. forest with a. a.era.e seedlings of 24767/hm., while only 40 regenera.ing tree species were recorded from.enrichm.nt pla.-ta.ions with a. a.era.e seedlings of 18633/hm.. m.xim.m.regenera.ion in na.ura. forest wa. found with Ca.ta.opsis spp. (2200 seedlings/hm.) followed by Glochidion la.ceola.ium.(2183 /hm.) wherea., in enrichm.nt pla.ta.ions m.xim.m.regen-era.ion wa. found with Dipteroca.pus gra.ilis (2117/hm.) followed by a.ogeissus a.um.na.a.(2000/hm.). For na.ura. forest, highest rela.ive density wa. found for Ca.ta.opsis spp (8.88%), rela.ive frequency for Glochidion la.ceola.ium.(7.36%), rela.tive a.unda.ce for Syzygium.spp. (3.79%) a.d Im.orta.ce Va.ue Index were recorded with Glochidion la.ceola.ium.(18.24%). The corresponding va.ues for enrichm.nt pla.ta.ions were highest with Dipteroca.pus gra.ilis (11.36%), Glochidion la.ceo-la.ium.(9.71%), Dipteroca.pus gra.ilis (5.92%), Glochidion la.ceola.ium.(23.32%) respectively. Stem.per hecta.e of som. com.on trees with their seedlings a.d sa.lings in both the na.ura. sta.ds a.d enrichm.nt pla.ta.ions showed tha. only Dip-teroca.pus gra.ilis successfully recruited in both sites but recruitm.nt wa. higher in na.ura. forest. Like m.ny other prim.ry ra.n forests, the Ba.a.toli forest typica.ly ha. both substa.tia. seedlings a.d soil seed ba.k from.which regenera.ion m.y occur. The na.ura.ly regenera.ed seedlings a.e quite dense but it could not rea.h the pole sta.e due to hum.n interference.

关键词： Regenera.ion Na.ura. forest Enrichm.nt pla.ta.ions Rela.ive density Frequency a.unda.ce Im.orta.ce Va.ue Index