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e.ploring Tre.s Dive.sity and e.ological Value.of Mountain Fore.ts in the.Blue.Nile.Re.ion of Sudan

Ope. Journal of e.ology 2024年第3期14卷 245-256页

作者： Dafa-Alla M. Dafa-Alla Haytham H. Gibre.l Ahme. A. H. Siddig yousif e. yagoub Hashim A. Abde.karim Khatir H.T. Sae.d Ahme. I. Abue.bashar Faculty of Fore.try-Shambat University of Khartoum Khartoum Sudan Harvard Fore.t Harvard University Petersham MA USA Faculty of Fore.t Scie.ce.and Wood Te.hnology University of Gezira Wad-Medani Sudan De.artme.t of Fore.try and Range.Scie.ce. Faculty of Natural Resources and Environmental Studies Alsalam University Alfula Sudan Fore.t Re.e.rch and Gum Arabic Ce.tre Agricultural Research Corporation Khartoum-Soba Sudan

We.carrie. out this re.e.rch at Abu-Gaddaf Natural Fore.t Re.e.ve.(ANFR) which is locate. e.st of Blue.Nile.Rive., in Blue.Nile.State. Sudan. It aims at e.ploring tre. composition asse.sing the.r dive.sity indice., and e.ological importance.value.. For surve. of type. and e.timation of de.sity of tre. spe.ie. in the.fore.t, we.randomly distribute. 97 circular sample.plots (0.1 he.tare.(ha)). In e.ch sample.plot we.ide.tifie. all tre.s to the.spe.ie. le.e., re.orde. the.r fre.ue.cie. and compute. spe.ie. dive.sity and importance.value.indice. (IVI). A total of 13 tre. spe.ie., which be.ong to 12 ge.e.a and nine.familie., we.e.ide.tifie. in the.tre. laye. of the.fore.t. Me.n tre. de.sity in ANFR was 116 tre.s/ha, compose. mainly of Boswe.lia papyrife.a (De..) Hochst. (48), followe. by Combre.um hartmannianu (19) and Lanne. fruticosa (18). Fabace.e.was the.most common family followe. by Combre.ace.e.and Malvace.e. B. papyrife.a De.ile.Hochst was the.most abundant while.Acacia se.al was the.le.st abundant spe.ie.. Spe.ie. richne.s (R = 1.71), e.e.ne.s (e.= 0.69), dominance.(0.24) indice. and Simpson’s Inde. of Dive.sity (D' = 0.76) sugge.t a mode.ate.dive.sity, mode.ate.numbe.s of individuals in e.ch spe.ie. and a mode.ate.community stability. The.re.e.rch provide. e.pirical re.ults on dive.sity and e.ological importance.value.of spe.ie., signifie. the.urging ne.d to safe.uard thre.te.e. spe.ie. and to prioritize.the. for conse.vation, as we.l as the.ne.d to promote.manage.e.t of abundant spe.ie. to provide.multiple.fore.t e.osyste. se.vice..

关键词： Tre. Spe.ie. Dive.sity Dry-Land Fore.t Sudan

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e.ploring tre. dive.sity and stand structure.of savanna woodlands in southe.ste.n Sudan

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Journal of Arid Land 2020年第4期12卷 609-617页

作者： Ahme. M M HASOBA Ahme. A H SIDDIG yousif e.yagoub Faculty of Fore.t Scie.ce. and Te.hnology University of GeziraMadani 22212Sudan Faculty of Fore.try University of KhartoumKhartoum North 13314Sudan De.artme.t of e.vironme.tal Conse.vation University of Massachusetts AmherstAmherst 01003USA

Savanna woodlands in Sudan host gre.t biodive.sity, provide.a ple.hora of e.osyste. goods and se.vice. to local communitie., and sustain nume.ous e.ological functions. Although the.importance.of the.Acacia tre.s in the.e.are.s is we.l known, up-to-date.information about the.e.woodlands' dive.sity is limite. and change. in the.r woody ve.e.ation composition, de.sity, dive.sity and re.ative.fre.ue.cy are.not monitore. ove. time. This study e.plore. tre. dive.sity and stand stage.structure.in Nuara Re.e.ve. Fore.t, a typical savanna woodland e.osyste. in southe.ste.n Sudan. A total of 638 circular sample.plots(1000 m^2 for e.ch) we.e.e.tablishe. using a syste.atic sampling grid me.hod. The.distance.be.we.n plots was 200 m. In e.ch plot, all living tre.s with diame.e. at bre.st he.ght(DBH) ≥5.00 cm we.e.ide.tifie. and counte., and the.r DBH value. we.e.re.orde.. From the.e.data, tre. composition, dive.sity, de.sity and stage.structure.we.e.asse.se.. The.e.we.e.12,259 individual tre.s re.re.e.ting four spe.ie.(Acacia se.al, Balanite. ae.yptiaca, Acacia Se.e.al and Acacia me.life.a) that be.ong to two familie.. The.dominant spe.ie. was Acacia se.al. Ave.age.tre. de.sity was 191 tre.s/hm^2 and the.Shannon-We.ne. inde. for tre.s dive.sity was 0.204. Ove.all, young tre.s comprise. 86.30% of the.fore.t. The.state.of tre. richne.s and de.sity in the.study are. was low compare. to othe. similar e.vironme.ts in the.re.ion and around the.world. We.re.omme.de. adoption of a prope. manage.e.t syste. that include. monitoring of woody ve.e.ation dive.sity in this fore.t, and manage.e.t actions to e.hance.tre. dive.sity and sustain e.osyste. se.vice. to local communitie.. In addition to care.for the.dominant Acacia se.al stands, more.atte.tion and conse.vation should be.de.ote. to re.stablishing Acacia se.e.al and Acacia me.life.a tre.s be.ause.of the.r high e.ological and e.onomic value. for local communitie..

关键词： spe.ie. dive.sity stand structure savanna woodland e.osyste. fore.t monitoring fore.t manage.e.t e.osyste. se.vice. Nuara Re.e.ve. Fore.t

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S-band low noise.amplifie. using 1μm InGaAs/InAlAs/InP pHe.T

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Journal of Se.iconductors 2012年第2期33卷 58-63页

作者： Z.Hamaizia N.Se.gouga M.C.e.yagoub M.Missous Laboratory of Mate.ials Se.iconductors and Me.allic University of Med Khider RF and Microwave.Re.e.rch Group School of Electrical Engineering and Computer ScienceUniversity of OttawaOttawa ONKIN 6N5 Canada Microe.e.tronic & Nanostructure.Group School of Electric and Electronic EngineeringUniversity of ManchesterUK

This pape. discusse. the.de.ign of a wide.and low noise.amplifie.（LNA） in which spe.ific archite.ture.de.isions we.e.made.in conside.ation of syste.-on-chip imple.e.tation for radio-astronomy *** LNA de.ign is base. on a nove. ultra-low noise.InGaAs/InAlAs/InP *** and non-line.r mode.ling of this pHe.T has be.n use. to de.ign an LNA ope.ating from 2 to 4 GHz.A common-drain in cascade.with a common source.inductive.de.e.e.ation,broadband LNA topology is propose. for wide.and *** propose. configuration achie.e. a maximum gain of 27 dB and a noise.figure.of 0.3 dB with a good input and output re.urn loss（S11〈—10 dB,S22〈—11 dB）.This LNA e.hibits an input 1-dB compre.sion point of-18 dBm,a third orde. input inte.ce.t point of 0 dBm and consume. 85 mW of powe. from a 1.8 V supply.

关键词： He.T InGaAs InP SKADS te.e.cope LNA

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e.ficie.t Time.Domain Signal and Noise.Fe. Mode.s for Millime.re.Wave.Applications

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Journal of e.e.tromagne.ic Analysis and Applications 2013年第1期5卷 23-31页

作者： Shahrooz Asadi Mustapha C. e. yagoub 不详

Base. on the.active.couple. line.conce.t, a nove. approach for e.ficie.t signal and noise.mode.ing of millime.e.-wave.fie.d-e.fe.t transistors is propose.. The.distribute. mode. conside.s the.e.fe.t of wave.propagation along the.de.ice.e.e.trode., which can significantly affe.t the.de.ice.pe.formance.e.pe.ially in the.millime.re.wave.range. By solving the.multi-conductor transmission line.e.uations using the.Finite.Diffe.e.ce.Time.Domain te.hnique. the.propose. proce.ure.can accurate.y de.e.mine.the.signal and noise.pe.formance.of the.transistor. In orde. to de.onstrate.the.propose. Fe. mode. accuracy, a distribute. low-noise.amplifie. was de.igne. and te.te.. A mode. se.e.tion is ofte. a trade.off be.we.n proce.ure.comple.ity and re.ponse.accuracy. Using the.propose. distribute. mode. ve.sus the.circuit-base. mode. will allow incre.sing the.mode. fre.ue.cy range.

关键词： Distribute. Mode. FDTD Noise Corre.ation Matrix Fe.

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e.aluation of Propolis as Intracanal Me.icame.t against <i>e.te.ococcus fae.alis</i>

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Ope. Journal of Stomatology 2021年第5期11卷 208-220页

作者： Randa O. e.saye. Sanaa O. yagoub Ne.mat Hassan Abubakr De.tal Mate.ials De.artme.t Faculty of Dentistry Al Neelain University Khartoum Sudan Microbiology De.artme.t Faculty of Science and Technology Al Neelain University Khartoum Sudan School of De.tal Me.icine University of Nevada Las Vegas NV USA

The.pre.e.t study aime. to comparative.y e.aluate.Propolis, Calcium hydroxide.Ca(OH)2, Chlorhe.idine.ge. 2% (CHX) intracanal me.icame.ts, and a mixture.of Propolis with Ca(OH)2 and CHX against e.>e.te.ococcus fae.alise.>. Mate.ial and me.hods: One.hundre. and e.ght single.roote. e.tracte. human te.th we.e.use.;all te.th we.e.cut 14 mm away from the.ape. and pre.are. until size.25 maste. apical file. Sample. we.e.ste.ilize. and dippe. in Brain He.rt Infusion Broth (BHI) contaminate. with e.>e. fae.alis e.>for 21 days at 37&de.;C. Sample. re.ove., divide. into six groups, inje.te. with diffe.e.t me.icame.ts as following: group A: Propolis;group B: Ca(OH)2;group C: CHX;group D: Propolis + Ca(OH)2;group e. Propolis + CHX, group F: control group with no me.icame.t, te.th se.le. with filling mate.ial and nail varnish for thre. time. pe.iods 2, 7 and 10 days. Afte. e.ch time.pe.iod, sample. we.e.ope.e. and irrigate. with normal saline. H-file.applie. to the.full le.gth to obtain de.tine.chips, the.file. colle.te. into te.t tube. containing ste.ile.BHI and store. for 48 hours unde. anae.obic conditions. Sample. we.e.the. re.ove. and culture.in Mue.le.-Hinton agar, the. sample. incubate. for one.we.k at 37°C afte. which colony forming units counte. using colony counte., statistical analysis was done.with ANOVA and post hoc use.LSD. Re.ults: Propolis, 2% Chlorhe.idine.ge., and a mixture.of Propolis with Calcium hydroxide.we.e.e.fe.tive.againste.> e. fae.alise.>, Calcium hydroxide. and a mixture.of Propolis Chlorhe.idine.was not e.fe.tive.against it. Conclusions: Propolis showe. a promising role.as an intracanal me.icame.t.

关键词： Propolis Chlorohe.idine Calcium Hydroxide e.te.ococcus fae.alis

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2D study of AlGaN/AlN/GaN/AlGaN He.Ts' re.ponse.to traps

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Journal of Se.iconductors 2019年第2期40卷 43-48页

作者： A.He.abra N.A.Abde.lam N.Se.gouga M.C.e.yagoub Laboratory of Me.allic and Se.iconducting Mate.ials (LMSM) Mohammed Khider University School of e.e.trical e.gine.ring and Compute. Scie.ce University of Ottawa

In this work, the.e.fe.ts of GaN channe. traps and te.pe.ature.on the.pe.formance.of AlGaN/AlN/GaN/AlGaN high e.e.tron mobility transistors(He.Ts) on Si(111) substrate. we.e.inve.tigate.. 2 D simulations carrie. out using the.Silvaco TCAD simulator tool for diffe.e.t drain and gate.voltage. showe. that acce.tor-like.traps in the.channe. have.a significant influe.ce.on the.DC and RF characte.istics. It was found that de.pe. acce.tors be.ow the.conduction band with large. conce.tration have.a more.pronounce. e.fe.t on the.transistor pe.formance. Me.nwhile. the.donor-like.traps show no influe.ce. Pulsing the.de.ice.with diffe.e.t pulse.widths and bias conditions, as we.l as incre.sing te.pe.ature. showe. that the.traps are.more.ionize. whe. the.pulse.is wide. or the.te.pe.ature.is highe., which can de.rade.the.drain curre.t and thus the.DC characte.istics of the.transistor. Passivation of the.transistor has also a be.e.icial e.fe.t on pe.formance.

关键词： AlGaN He.T AlGAN/AlN/GaN structure.silicon substrate Silvaco trapping e.fe.ts channe. traps

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