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Impurity effects on electrical conductivity of doped bilayer graphene in the presence of a bias voltage

Chinese Physics B 2016年第7期25卷 316-323页

作者： E Lotfi H Rezania B Arghavaninia m yarmohammadi Department of Physics Sanandaj Branch Islamic Azad University Department of Physics Razi University Department of Physics Kermanshah Branch Islamic Azad University Young researchers and Elite Club Kermanshah Branch Islamic Azad University

We address the electrical conductivity of bilayer graphene as a function of temperature, impurity concentration, and scattering strength in the presence of a finite bias voltage at finite doping, beginning with a description of the tight-binding model using the linear response theory and Green＇s function approach. Our results show a linear behavior at high doping for the case of high bias voltage. The effects of electron doping on the electrical conductivity have been studied via changing the electronic chemical potential. We also discuss and analyze how the bias voltage affects the temperature behavior of the electrical conductivity. Finally, we study the behavior of the electrical conductivity as a function of the impurity concentration and scattering strength for different bias voltages and chemical potentials respectively. The electrical conductivity is found to be monotonically decreasing with impurity scattering strength due to the increased scattering among electrons at higher impurity scattering strength.

关键词： bilayer graphene Green's function electrical conductivity

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Synthesis of NaA zeolite using PTmAOH(phenyltrimethylammoniumhydroxide): hydrothermal and microwave heating methods and comparison of their XRD patterns

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Open Journal of Inorganic Chemistry 2012年第1期2卷 1-5页

作者： S. N. Azizi A. R. Samadi-maybodi m. yarmohammadi 不详

Ion exchanging is one of the characteristics of the zeolites. Zeolites have octahedral and tetrahedral holes to trap ions and molecules. They also can exchange many ions in solution because of the size of the attendant ions. As a matter of fact, the property of the ion-exchanged zeolites depends on the ligands involved in the ion exchanging solutions. Ion exchanged zeolites are used as catalyst for studying the anodic oxidation of methanol in an acidic medium to investigate their suitability for use in direct methanol fuel cells (DmFCs). Some of the zeolites that have exchanged ions are shown to have redox and catalytic properties [1-3]. As an example A. Itadani et al., have reported the preparation of copper ion exchanged ZSm-5 for calorimetric study of N2 adsorption on Cu-ZSm-5 zeolite [4]. In another study, A. Ribera et al. have reported the characterization of redox properties and application of Fe-ZSm-5 catalysts [5]. In this research we prepared silicate solutions by dissolving silica in sodium hydroxide. Aluminosilicate solutions with different Al/Si ratios were prepared by mixing appropriate quantities of sodium silicate solutions with freshly prepared sodium aluminate solutions and the NaA zeolites were made by hydrothermal method. Then, their XRD patterns and IR spectra were also considered. Obviously, those zeolites which have Al-OH and Si-OH groups can lose their protons in basic solutions. In this way zeolites can adsorb many ions with positive charge. We investigated ion exchange property of Fe3+, Cu2+, Ni2+ and Hg2+ in systems with pH equals to 2, 4, 6 and 8. We found that the aluminosilicate with Si/Al = 1, has greatest exchange capacity for all of the ions studied in this work.

关键词： Zeolite NaA PTmAOH microwave Heating Hydrothermal

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Bound states of Dirac fermions in monolayer gapped graphene in the presence of local perturbations

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Chinese Physics B 2016年第6期25卷 563-568页

作者： mohsen yarmohammadi malek Zareyan Young Researchers and Elite Club Kermanshah BranchIslamic Azad University Department of Physics Institute for Advanced Studies in Basic Sciences (IASBS)

In graphene,conductance electrons behave as massless relativistic particles and obey an analogue of the Dirac equation in two dimensions with a chiral *** this reason,the bounding of electrons in graphene in the form of geometries of quantum dots is *** gapless graphene,due to its unique electronic band structure,there is a minimal conductivity at Dirac points,that is,in the limit of zero *** creates a problem for using such a highly motivated new material in electronic *** of the ways to overcome this problem is the creation of a band gap in the graphene band structure,which is made by inversion symmetry breaking（symmetry of sublattices）.We investigate the confined states of the massless Dirac fermions in an impured graphene by the short-range perturbations for ＂local chemical potential＂ and ＂local gap＂.The calculated energy spectrum exhibits quite different features with and without the perturbations.A characteristic equation for bound states（BSs） has been *** is surprisingly found that the relation between the radial functions of sublattices wave functions,i.e.,f_m~＋（r）,g_m~＋（r）,and f_m^-（r）,g_m^-（r）,can be established by SO（2） group.

关键词： monolayer gapped graphene quantum dots bound states inversion symmetry breaking

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以目前的反应标准比较使用经动脉化学栓塞治疗肝细胞癌病人的3D定量方法

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国际医学放射学杂志 2016年第2期 187-187页

作者： V.Tacher m.D.Lin R.Duran H.yarmohammadi H.Lee J.Chapiro 李唐 Russell H. morgan Department of Radiology and Radiological Science Division of Vascular and Interventional Radiology Johns Hopkins Hospital

摘要目的在预测传统的经导管动脉化学栓塞术(TACE)治疗后病人的存活时间中,以目前可用的非3D方法[反应实体肿瘤诊断标准(RECIST),欧洲肝脏研究协会(EASL)标准,改良版反应实体肿瘤诊断标准(m RECIST)]来比较用标记肿瘤作为早期反应标志物... 详细信息

摘要目的在预测传统的经导管动脉化学栓塞术(TACE)治疗后病人的存活时间中,以目前可用的非3D方法[反应实体肿瘤诊断标准(RECIST),欧洲肝脏研究协会(EASL)标准,改良版反应实体肿瘤诊断标准(m RECIST)]来比较用标记肿瘤作为早期反应标志物的3D定量方法。材料与方法该回顾性研究由HIPAA单一机构和机构伦理委员会批准研究。选取2001年11月—2008年11月期间491例

关键词：肝细胞癌存活时间病人 RECIST 定量方法 TACE 反应动脉

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