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Moderate concentration of citric acid for the formation of LaMnO3 and LaCoO3 nano-perovskites

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Journal of Rare Earths 2013年第10期31卷 997-1002页

作者： Elham Ghiasi azim malekzadeh Mahnaz Ghiasi School of Chemistry Damghan University

Stoichiometric LaMnO3and LaCoO3nanoparticles were synthesized via calcination of a dried solution,containing molar ratio of La(NO3)3·6H2O/[Mn(NO3)2·4H2O or Co(NO3)2·6H2O]=1 and citric acid as disperser at temperature range of 600–900 oC for 5 *** role of organic additive concentration,which was 0.0,1.0,2.5 and 5 times of the total number of moles of the nitrate ions,was investigated on phase formation,morphology,extent of crystallization and particle size of the *** were characterized by X-ray diffraction(XRD),Fourier-transform infrared spectroscopy(FT-IR),scanning electron microscopy(SEM)and transmission electron microscopy(TEM)*** tendency of lanthanum ion toward manganese cation was observed to be more than to cobalt cation for the formation of LaBO3(B:Mn or Co)perovskite phase.A spongy product was formed on perovskite phase formation or in the presence of citric acid.A constructive or destructive effect was observed for the organic disperser on perovskite phase formation,which depended on mole of the citric acid.

关键词： mixed oxides LaMnO3 LaCoO3 nano-perovskite citric acid rare earths

Oxidative coupling of methane over (Na_2WO_4+Mn or Ce)/SiO_2 catalysts:In situ measurement of electrical conductivity

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Journal of Natural Gas Chemistry 2010年第1期19卷 35-42页

作者： Zeinab Gholipour azim malekzadeh Reza Hatami Yadollah Mortazavi Abasali Khodadadi School of Chemistry Damghan University of Basic Sciences (DUBS) P.O. Box 36715/364 Damghan I. R. Iran Catalysis and Nanostructured Materials Research Laboratory School of Chemical Engineering University of Tehran P.O. Box 11365/4563 Tehran I. R. Iran

The effects of manganese oxide or ceria promoters on the performance of Na2WO4/SiO2 catalysts for oxidative coupling of methane （OCM） are reported. The OCM reaction was performed in a continuous-flow microreactor at 800℃, atmospheric pressure and under GHSV = 13200 ml·gCat^-1·h^-*** were characterized by in situ conductivity measurement, FT-IR spectroscopy, XRD, SEM and temperature programmed reduction analysis. Manganese oxide promoted Na2WO4/SiO2 is considered as one of the active and selective catalysts for OCM reaction. Ceria with high oxygen storage capacity is selected as a proper oxygen activator, providing a higher concentration of the oxy-anion species which is suitable for OCM reaction and compared with manganese oxide. Electrical conductivity of the catalysts was measured in OCM reaction under oxidizing atmosphere, i.e. in the absence of methane. It was found that the trimetallic catalysts, i.e. the catalysts having sodium, tungsten and Mn or Ce species, exhibited similar crystalline structures and morphologies, which lead to suitable bulk properties for the formation of an active and selective catalyst. However, tungsten had significant effect on the texture and redox properties of the catalysts. It was also shown that the crystalline structure of the bimetallic （Na＋Mn or Ce）/SiO2 samples was quite different. This reveals that the metal oxides have significant effect on the extent of crystallization, taking place in the course of interaction of sodium with silica support. Similar conductivities and catalytic performances of （Na2WO4＋Mn or Ce）/SiO2 catalysts propose that the ability of Na2WO4/SiO2 for utilizing oxy-anions formed in presence of different metal oxides is limited.

关键词： oxidative coupling of methane (OCM) conductivity manganese oxide ceria TPR

A Survey and Tutorial of EEG-Based Brain Monitoring for Driver State Analysis

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IEEE/CAA Journal of Automatica Sinica 2021年第7期8卷 1222-1242页

作者： Ce Zhang azim Eskandarian Virginia Tech Mechanical Engineering Department ASIM Lab Virginia 24061-0131 USA

The driver’s cognitive and physiological states affect his/her ability to control the ***,these driver states are essential to the safety of *** design of advanced driver assistance systems(ADAS)or autonomous vehicles will depend on their ability to interact effectively with the driver.A deeper understanding of the driver state is,therefore,***(EEG)is proven to be one of the most effective methods for driver state monitoring and human error *** paper discusses EEG-based driver state detection systems and their corresponding analysis algorithms over the last three ***,the commonly used EEG system setup for driver state studies is ***,the EEG signal preprocessing,feature extraction,and classification algorithms for driver state detection are ***,EEG-based driver state monitoring research is reviewed in-depth,and its future development is *** is concluded that the current EEGbased driver state monitoring algorithms are promising for safety ***,many improvements are still required in EEG artifact reduction,real-time processing,and between-subject classification accuracy.

关键词： Advanced driver assistance systems(ADAS) data analysis electroencephalography(EEG) intelligent vehicles machine learning algorithms neural network.

Dark count rate and band to band tunneling optimization for single photon avalanche diode topologies

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Chinese Physics B 2019年第6期28卷 458-464页

作者： Taha Haddadifam Mohammad azim Karami Iran University of Science and Technology

This paper proposes two optimal designs of single photon avalanche diodes(SPADs) minimizing dark count rate(DCR). The first structure is introduced as p^+/pwell/nwell, in which a specific shallow pwell layer is added between p^+and nwell layers to decrease the electric field below a certain threshold. The simulation results show on average 19.7%and 8.5% reduction of p^+/nwell structure’s DCR comparing with similar previous structures in different operational excess bias and temperatures respectively. Moreover, a new structure is introduced as n+/nwell/pwell, in which a specific shallow nwell layer is added between n+and pwell layers to lower the electric field below a certain threshold. The simulation results show on average 29.2% and 5.5% decrement of p^+/nwell structure’s DCR comparing with similar previous structures in different operational excess bias and temperatures respectively. It is shown that in higher excess biases(about 6 volts), the n+/nwell/pwell structure is proper to be integrated as digital silicon photomultiplier(dSiPM) due to low DCR. On the other hand, the p^+/pwell/nwell structure is appropriate to be utilized in dSiPM in high temperatures(above 50?C) due to lower DCR value.

关键词： single-photon avalanche diode digital silicon photomultiplier dark count rate

Analytical and statistical calculation of gamma dose rate for the accident of losing the shield for Tehran Research Reactor

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Chinese Physics C 2008年第11期32卷 877-881页

作者： Farshid Tabbakh azim Ahmadinyar School of Nuclear Science Institute of Nuclear Reactors and Accelerators Atomic Energy Organization of Iran North Kargar Av. Tehran Iran

In this paper we study the analytical and statistical results of estimating the gamma dose rate at pool access floor in TRR when the core shield accidentally decreases to some non-permitted levels. Due to the risk of experimental techniques, we use the analytical and statistical methods. In normal conditions （no risk）, the discrepancies between experiment and two methods are justified and it is found that for such problems we have to normalize these methods to experimental results as follows： the analytical method by factor 0.13 and MCNP by 1.7.

关键词： TRR gamma-ray dose rate MCNP4C

A hybrid simulation approach to evaluate stimulation micro-seismic events and production potential of fractured geothermal reservoirs

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Petroleum Research 2020年第2期5卷 131-143页

作者： Reda Abdel azim Petroleum Engineering Department American University of Kurdistan Zakho Rd.99641DohoukIraq

This study presents an integrated approach to simulate fluid flow and to predict the micro seismic eventsduring stimulation and circulation of cold water over a longer term in geothermal reservoirs. The integrated approach based on new three dimensional fully coupled thermo-poroelastic numerical model forevaluation of energy recoverable. In the presented approach, the fracture aperture due to fractureslippage is calculated by shear and dilation. The shear slippage is controlled by the concept of shearfailure using linear Mohr-Coulomb criterion. The numerical model is validated against an analytical Oda’smodel for permeability tensor calculation and against an analytical solution for thermo-poroelasticmodel. The heat transfer between the rock and fluid is modelled by using the conductive heat transferwithin the reservoir rock and convective heat transfer in discrete fractures. The thermal stress changesare included in the model to be studied by using roughness induced shear displacement principle in aporo-thermo-elastic environment. The fracture aperture changes are estimated by using an analyticalmodel based on the distributed dislocation technique. The roughness of fracture surfaces is used in thecalculation of residual fracture aperture. The presented approach is used to study the potential ofpermeability enhancement for Habanero geothermal reservoir at a depth of 3600 m. The result show thatthe increasing in tensile effective stress tend to increase the fracture aperture within the zone of *** increasing in fracture aperture led to significant changes in pressure distribution (decrease inimpedance) and hence, increase in the flow rate.

关键词： Fractured reservoirs Finite element Permeability tensor Fracture aperture Tensile stress Fractal density and dimension

A poroelastic numerical model for simulation of hydraulic fracture propagation:Application to Upper Safa formation-Western Desert-Egypt

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Petroleum Research 2020年第1期5卷 39-51页

作者： Reda Abdel azim Petroleum Engineering Department American University of KurdistanDohoukIraq

The hydraulic fracturing in tight sand formations has a significant importance in improving its production *** this study,a poroelastic numerical model is presented in order to study the reservoirs and rock mechanical properties that affect the propagation of the hydraulic *** poroelastic model simulate fully coupled fluid flow,pressures and stress changes by using finite element *** results show that the formation permeability and fracture toughness are key parameters in the design of hydraulic fracture treatment.A case study applied in Upper Safa formation in a well-located western desert *** formation is very tight with permeability of 0.1md and the objective here is to optimize the design procedures for hydraulic fracture *** results show that the formation needs to be pumped for about 5min to produce hydraulic fracture length of 182 *** addition,the total pumping time(30 min)is vital to produce the desired total fracture length of 1000 ft.

关键词： Fracture propagation Finite element Upper Safa formation Poroelastic Leak off model

Insights into ligand expression heterogeneity across multiple cell types in the adult forebrain that regulates neural stem cell behavior

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Neural Regeneration Research 2019年第8期14卷 1369-1371页

作者： Rainer Akkermann Kasum azim Department of Neurology and Neuroregeneration Medical FacultyHeinrich-Heine-University

In the adult mammalian central nervous system (CNS), neural cell generation is restricted to two highly specialized germinal niches. These are the subventricular zone (SVZ) that borders the forebrain lateral ventricles and the subgranular zone of the hippocampus. In the case of the former niche, the SVZ gives rise daily to thousands of migratory neuroblasts that travel long distances to the olfactory bulb via the rostral migratory stream. Neural stem cells (NSCs) first engage through a sequence of activation phe no types and give rise to transiently amplifying progenitors (TAPs) that subsequently differentiate into neuroblasts. Once in the olfactory bulb, they generate phenotypically distinct neurons. Most of these constitute the interneuron class that is preferentially derived from the lateral portion of the SVZ, whilst a small proportion of projection neurons are also formed from the dorsal SVZ.

关键词： Insights ligand expression cell behavior

Effect of Residual Charge Carrier on the Performance of a Graphene Field Effect Transistor

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Chinese Physics Letters 2016年第1期33卷 113-117页

作者： Sedighe Salimian Mohammad Esmaeil azim Araghi Faculty of Physics Kharazmi University

The temperature-dependent effect of residual charge carrier （no）, at the Dirac point, on mobility is studied. We fabricate and characterize a graphene field effect transistor （GFET） using 7nm TiO2 as the top-gate dielectric. The temperature-dependent gate voltage-drain current and room temperature gate capacitance are measured to extract the carrier mobility and to estimate the quantum capacitance of the GFET. The device shows the mobility value of gOO cm^2 /V.s at room temperature and it decreases to 45 cm^2 /V.s for 20 K due to the increase of n0. These results indicate that the phonon scattering is not the dominant process for the unevenness dielectric layer while the coulomb scattering by charged impurities degrades the device characteristically at low temperature.

关键词： of it by Effect of Residual Charge Carrier on the Performance of a Graphene Field Effect Transistor on is VTG high for into that