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Chinese Physics B 2023年第6期32卷 259-269页

作者： H ahmad B Nizam.ni m.Z Sam.on N Yusoff m.f Ism.il Photonics Research Centre Universiti Malaya50603 Kuala LumpurMalaysia Physics Departm.nt Faculty of ScienceUniversiti Malaya50603 Kuala LumpurMalaysia Distinguished Visiting Professor Universiti Kuala Lumpur British Malaysian Institute(UniKL BMI)Batu 8Jln Sungai Pusu53100SelangorMalaysia

We dem.nstrate antim.nene as a saturable absorber(SA) to generate an ultrafast m.de-locked and Q-switched laser in the 2 μm.wavelength region. The two antim.nene-based SAs were prepared and inserted separately in a thulium.holm.um.oped fiber laser to produce the pulsed laser. Antim.nene was coated onto a tapered fiber to generate soliton m.de-locked pulses and used in thin-film.form.for the generation of Q-switched pulses. The m.de-locking was stable within a pum. power of 267 m.W–511 m.W, and the laser operated at a central wavelength of 1897.4 nm. The m.de-locked laser had a pulse width of 1.3 ps and a repetition rate of 12.6 m.z, with a signal-to-noise ratio of 64 d B. Q-switched laser operation was stable at a wavelength of 1890.1 nm.within a pum. power of 312 m.W–381 m.W. With the increase in pum. power from.312 m.W to 381 m.W, the repetition rate increased to a m.xim.m.of 56.63 k Hz and the pulse width decreased to a m.nim.m.value of 2.85 μs. Wide-range tunability of the Q-switched laser was also realized within the wavelength range of1882 nm.1936 nm.

关键词： m.de-locking Q-switched fiber laser optical saturable absorber

One-loop approxim.tion of m.ller scattering in generalized Krein-space quantization

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Science China(Physics,m.chanics & Astronom.) 2009年第2期52卷 212-217页

作者： f. PAYANDEH m. m.HRAfARIN m. V. TAKOOK Physics Departm.nt Amirkabir University of Technology Payam. Noor University Physics Departm.nt Razi University

It has been shown that the negative-norm.states necessarily appear in a covariant quantization of the free m.nim.lly coupled scalar field in de Sitter spacetim.. In this processes ultraviolet and infrared di- vergences have been autom.tically elim.nated. A natural renorm.lization of the one-loop interacting quantum.field in m.nkowski spacetim. (λφ 4) has been achieved through the consideration of the nega- tive-norm.states defined in Krein space. It has been shown that the com.ination of quantum.field theory in Krein space together with consideration of quantum.m.tric fluctuation, results in quantum.field the- ory without any divergences. Pursuing this approach, we express Wick’s theorem.and calculate m.ller scattering in the one-loop approxim.tion in generalized Krein space. The m.them.tical consequence of this m.thod is the disappearance of the ultraviolet divergence in the one-loop approxim.tion.

关键词： quantum field theory Krein space negative energy states

Bioaccum.lation of m.tals in hum.n blood in industrially contam.nated area

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Journal of Environm.ntal Sciences 2011年第12期23卷 2069-2077页

作者： f. Akbar Jan m. Ishaq S. Khan m. Shakirullah S. m. Asim.I. ahmad fazal m.bood Institute of Chem.cal Sciences University of Peshawar 25120 Khyber-Pukhtunkhwa Pakistan Departm.nt of Environm.ntal Sciences University of Peshawar Peshawar Pakistan Departm.nt of Statistics University of Peshawar Peshawar Departm.nt of-Biological-Sciences ＆ Chem.stry University of Nizwa Nizwa Oman

Heavy m.tals were analyzed in different foods crops, m.lk, m.at and blood sam.les collected from.different age group subjects such as children （1–12 years）, adolescent （12–18 years）, adults （18–45 years） and old age （above 45 and 55 years for m.les and fem.les, respectively） from.polluted and relatively less polluted areas. The results revealed that the consum.tion of contam.nated food crops, m.at and m.lk have significantly increased the concentrations of selected m.tals in the hum.n blood. Cu, Zn and m. concentrations were significantly higher （p 0.05） in the blood sam.les collected from.the polluted area as com.ared to control area. Old people had accum.lated high concentrations of m.tals as com.ared to the younger ones within the sam. area. m.les accum.lated higher concentrations of m.tals as com.ared to fem.les.

关键词： bioaccum.lation heavy m.tals blood contam.nated m.at m.lk f.rage grass

The Efect of the Earthed Electrode Size on the Ignition Voltage of Low-Pressure Rf Capacitive Discharge in Argon

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Plasm. Science and Technology 2013年第9期15卷 881-884页

作者： A. A. AZOOZ m. A. ahmad Departm.nt of Physics College of ScienceMosul University Departm.nt of Physics College of EducationMosul University

The effect of the grounded electrode diam.ter on the ignition voltage using 13.56 m.z in argon gas is studied experim.ntm.y. The results indicate a system.tic decrease of the breakdown voltage with increasing electrode area for the sam. pd value. No m.lti-valued breakdown voltages are observed. The Paschen m.nim.m.is not affected by the electrode diam.ter as long as the parallel plane approxim.tion is valid. A m.dified Paschen equation which takes into account indirect discharge via the cham.er walls at high pd values gives reasonable fits to the experim.ntal data.

关键词： CCRf electrode size Paschen law Rf plasm.

Solubility prediction of disperse dyes in supercritical carbon dioxide and ethanol as co-solvent using neural network

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Chinese Journal of Chem.cal Engineering 2016年第4期24卷 491-498页

作者： ahmad KhazaiePoul m. Soleim.ni S. Salahi faculty of Water and Environm.ntal Engineering Shahid Beheshti University Tehran Iran Am.l University of Special m.dern Technologies Amo146168-49767 Iran Chem.cal Engineering Departm.nt Islamic Azad University Shahrood Branch Shahrood Iran

Nowadays artificial neural networkS （ANNs） with strong ability have been applied widely for prediction of non- linear phenom.non. In this work an optim.zed ANN with 7 inputs that consist of tem.erature, pressure, critical tem.erature, critical pressure, density, m.lecular weight and acentric factor has been used for solubility predic- tion of three disperse dyes in supercritical carbon dioxide （SC-C02） and ethanol as co-solvent. It was shown how a m.lti-layer perceptron network can be trained to represent the solubility of disperse dyes in SC-C02. Num.ric Sensitivity Analysis and Garson equation were utilized to find out the degree of effectiveness of different input variables on the efficiency of the proposed m.del. Results showed that our proposed ANN m.del has correlation coefficient, Nash-Sutcliffe m.del efficiency coefficient and discrepancy ratio about 0.998, 0.992, and 1.053 respectively.

关键词： SolubilityDisperse dyesSupercritical carbon dioxideNeural networksCo-solvent

Vanadium.pentoxide film.for m.crosecond pulse generation in 1.5-μm.region

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Optoelectronics Letters 2022年第1期18卷 29-34页

作者： m.ham.d f.Baharom.Salam.m.Azooz ahmad H.A.Rosol m.h Yasin Sulaim.n Wadi Harun Departm.nt of Electrical Engineering University of MalayaKuala Lumpur 50603Malaysia Departm.nt of Com.unication Engineering Engineering Technical CollegeAl-Furat Al-Awsat Technical UniversityNajafIraq Departm.nt of Physics Faculty of Science and TechnologyAirlangga UniversitySurabaya 60115Indonesia

Q-switched erbium.doped fiber laser(EDfL)was passively realized using vanadium.pentoxide(V_(2)O_(5))em.edded into polyethylene glycol(PEG)film.as saturable absorber(SA).The laser could successfully generate stable self-starting pulses when the V_(2)O_(5)film.was placed in an EDfL *** operated at 1562.4 nm.*** repetition rate can be varied from.91.7 kHz to 128.2 kHz while the pulse width shrank from.10.90μs to 7.81μs with rising pum. power from.110.9 m. to 166.5 *** pulse energy recorded was 3.2 nJ at pum. power of 166.5 *** results indicate that the saturable absorption of V_(2)O_(5)has prom.sing nonlinear photonic applications especially in fiber laser developm.nt for 1.5-μm.region.

关键词： pulse pum. fiber

Resonance Conversion as the Effective Way of Triggering the ^（178m.）Hf Isom.r Energy

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Chinese Physics Letters 2006年第8期23卷 2049-2051页

作者： f. feodor KARPESHIN m. B.TRZHASKOVSKAYA 张景波 Science Center and Departm.nt of Physics Harbin Institute of Technology Harbin 150001 fock Institute of Physics St. Petersburg State University RU-198504 St. Petersburg Russia PNPI RU-198355 St. Petersburg Leningrad District Russia

Experim.nts on photo-induced de-excitation triggering of ^（178m.）Hf are revisited. We present an alternative and m.re effective way of triggering by exploiting the resonance internal conversion. full theoretical description of a possible channel is presented. It is therefore revisited the im.act itself produced by those experim.nts.

关键词： Resonance Conversion Effective Way

Num.rical analysis for peristaltic transport of Carreau-Yasuda fluid with variable therm.l conductivity and convective conditions

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Journal of Central South University 2015年第11期22卷 4467-4475页

作者： f.m.Abbasi T.Hayat B.ahmad Departm.nt of m.them.tics Comsats Institute of Information Technology Departm.nt of m.them.tics Quaid-I-Azam University 45320 Nonlinear Analysis and Applied m.them.tics (NAAm. Research Group Faculty of Science King Abdulaziz University

Peristalsis of Carreau-Yasuda fluid is investigated. Analysis is carried out in the presence of velocity slip and convective boundary conditions. Therm.l conductivity of the fluid is taken to be tem.erature dependent. Lubrication analysis is used in the form.lation of the problem. Resulting nonlinear system.of equations is solved num.rically. Im.act of em.edded param.ters on the quantities of interest is exam.ned through graphs and tables. Com.arison of the behavior of the Carreau-Yasuda, Carreau and Newtonian fluid m.dels is presented. Results show that the heat transfer rate at the wall for the Carreau fluid m.del is large when com.ared with the Newtonian or the Carreau-Yasuda fluid m.del. Also the heat transfer rate at the wall decreases with increase in the velocity slip and variable therm.l conductivity param.ters. further, an increase in the Biot num.er reduces the fluid tem.erature by a considerable am.unt.

关键词： peristaltic transport Carreau-Yasuda fluid variabl

Separation of rare earth elem.nts from.sulfate leach liquor by heterocyclic nitrogen com.ound

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Journal of Rare Earths 2008年第4期26卷 544-551页

作者： GHADA m. m.hm.ud NABIL T. El Hazek ahmad m. f.rag Om.EYA m. El Hussaini Nuclear m.terials Authority P.O. Box 530 El Maadi Cairo Egypt Chem.stry departm.nt Faculty of Science Cairo University Giza Egypt

Separation of rare earth dem.nts by solvent extraction has actually been widely used in various fields from.analytical chem.stry to hydrom.tallurgy. A representative ore sam.le obtained from.Kadabora Batholiths-Eastern Desert of Egypt, containing the m.ltiple oxides rare earth m.nerals： Sam.rskite, fergusonite, Betafite, and Pyrochlore, was subjected to sulfuric acid leaching. Different sets of equilibrium.loading experim.nts were carded out on a bench scale for the extraction of rare earths （cerium.and yttrium. from.the sulfate leach liquor using 8,9-dihydro[1,2,4]triazolo[1,5-a]quinazolin-6（TH）-one {TQ} dissolved in m.thylene chloride. Stripping was carded out by 20% sodium.hydroxide. A rare earth cake was produced by oxalic acid precipitation. Its purity reached 87.3%.

关键词： triazolopyrim.dine extraction stripping precipitation rare earths

Accelerated D-Dim.nsional Com.actified Universe in Gauss-Bonnet-Dilatonic Scalar Gravity from.D-Brane/m.Theory

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Chinese Physics Letters 2008年第8期25卷 2785-2788页

作者： EL-NABULSI ahmad Ram. Departm.nt of Nuclear and Energy Engineering Cheju National University Ara-dong 1 Jeju 690-756 South Korea

We discuss a particular d-dim.nsional Gauss- Ronnet-dilatonie universe com.actified on S^1 m.tivated from.m.heory. We exam.ne the tim.-evolution of the dynam.cal equations where m.ny interesting consequences are revealed and discussed in som. details. Under reasonable conditions, the discussed m.del can provide a m.chanism.to realize, in higher-dim.nsions （d 〉 4）, the accelerated expansion of the universe in the presence of dark energy, without the presence of phantom.energy and without the contraction of som. internal dim.nsion.

关键词： COSm.LOGICAL CONSTANT CHAPLYGIN-GAS DARK ENERGY QUINTESSENCE SUPERNOVAE PLANETS Om.GA