Electrical transport in crystalline phase change materials

Energy Technology Data Exchange (ETDEWEB)

Woda, Michael

2012-01-06

In this thesis, the electrical transport properties of crystalline phase change materials are discussed. Phase change materials (PCM) are a special class of semiconducting and metallic thin film alloys, typically with a high amount of the group five element antimony or the group six element tellurium, such as Ge{sub 2}Sb{sub 2}Te{sub 5}. The unique property portfolio of this material class makes it suitable for memory applications. PCMs reveal fast switching between two stable room-temperature phases (amorphous and crystalline) realized by optical laser or electrical current pulses in memory devices. Additionally, a pronounced property contrast in form of optical reflectivity and electrical conductivity between the amorphous and crystalline phase is the characteristic fingerprint of PCMs. The emerging electrical solid state memory PCRAM is a very promising candidate to replace Flash memory in the near future or to even become a universal memory, which is non-volatile and shows the speed and cyclability of DRAM. One of the main technological challenges is the switching process into the amorphous state, which is the most power demanding step. In order to reduce the switching power, the crystalline resistivity needs to be increased at a given voltage. Thus understanding and tayloring of this property is mandatory. In this work, first the technological relevance, i.e. optical and electrical memory concepts based on PCMs are introduced. Subsequently a description of the physical properties of PCMs in four categories is given. Namely, structure, kinetics, optical properties and electrical properties are discussed. Then important recent developments such as the identification of resonant bonding in crystalline PCMs and a property predicting coordination scheme are briefly reviewed. The following chapter deals with the theoretical background of electrical transport, while the next chapter introduces the experimental techniques: Sputtering, XRR, XRD, DSC, thermal annealing

Effects of sintering temperature on structural and electrical transport properties of zinc ferrites prepared by sol-gel route

International Nuclear Information System (INIS)

Anis-ur-Rehman, M.; Malik, M.A.; Ahmad, I.; Nasir, S.; Mubeen, M.; Abdullah, A.

2011-01-01

The effects of sintering temperature on the structural and electrical transport properties of nanocrystalline zinc ferrites are reported. The zinc ferrites were prepared by WOWS sol-gel synthesis route. The prepared sample was sintered at temperatures 500 deg. C, 700 deg. C and 900 deg. C respectively for 2 h. X-ray Diffraction (XRD) technique was used to describe the structural properties. The crystallite size, lattice parameters and porosity of samples were measured from the analysis of XRD data. The average crystallite size for each sample was measured using the Scherrer formula by considering the most intense (3 1 1) peak. The dielectric constant (e), dielectric loss tangent (tan theta ) and AC electrical conductivity of nanocrystalline Zn ferrites are investigated as a function of frequency and sintering temperature. All the electrical properties are explained in accordance with MaxwellWagner model and Koops phenomenological theory. (author)

Electrical and thermal transport properties of layered Bi{sub 2}YO{sub 4}Cu{sub 2}Se{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Xiao, Yu; Pei, Yanling; Chang, Cheng; Zhang, Xiao [School of Materials Science and Engineering, Beihang University, Beijing 100191 (China); Tan, Xing [State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Ye, Xinxin [Department of Physics, South University of Science and Technology of China, Shenzhen 518055 (China); Gong, Shengkai [School of Materials Science and Engineering, Beihang University, Beijing 100191 (China); Lin, Yuanhua [State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); He, Jiaqing [Department of Physics, South University of Science and Technology of China, Shenzhen 518055 (China); Zhao, Li-Dong, E-mail: zhaolidong@buaa.edu.cn [School of Materials Science and Engineering, Beihang University, Beijing 100191 (China)

2016-07-15

Bi{sub 2}YO{sub 4}Cu{sub 2}Se{sub 2} possesses a low thermal conductivity and high electrical conductivity at room temperature, which was considered as a potential thermoelectric material. In this work, we have investigated the electrical and thermal transport properties of Bi{sub 2}YO{sub 4}Cu{sub 2}Se{sub 2} system in the temperature range from 300 K to 873 K. We found that the total thermal conductivity decreases from ~1.8 W m{sup −1} K{sup −1} to ~0.9 W m{sup −1} K{sup −1}, and the electrical conductivity decreases from ~850 S/cm to ~163 S/cm in the measured temperature range. To investigate how potential of Bi{sub 2}YO{sub 4}Cu{sub 2}Se{sub 2} system, we prepared the heavily Iodine doped samples to counter-dope intrinsically high carrier concentration and improve the electrical transport properties. Interestingly, the Seebeck coefficient could be enhanced to ~+80 μV/K at 873 K, meanwhile, we found that a low thermal conductivity of ~0.7 W m{sup −1} K{sup −1} could be achieved. The intrinsically low thermal conductivity in this system is related to the low elastic properties, such as Young's modulus of 70–72 GPa, and Grüneisen parameters of 1.55–1.71. The low thermal conductivity makes Bi{sub 2}YO{sub 4}Cu{sub 2}Se{sub 2} system to be a potential thermoelectric material, the ZT value ~0.06 at 873 K was obtained, a higher performance is expected by optimizing electrical transport properties through selecting suitable dopants, modifying band structures or by further reducing thermal conductivity through nanostructuring etc. - Highlights: • The total thermal conductivity decreases from 1.8 to 0.9 Wm{sup –1}K{sup –1} at 300–873K. • The electrical conductivity decreased from 850 to 163 S/cm at 300–873K. • The Seebeck coefficients were enhanced through heavily Iodine doping. • The ZT ~0.06 at 873K suggests that Bi{sub 2}YO{sub 4}Cu{sub 2}Se{sub 2} systems are potential thermoelectrical materials.

Characterization of the hole transport and electrical properties in poly(9,9-dioctylfluorene)

International Nuclear Information System (INIS)

Wang, L.G.; Zhang, H.W.; Tang, X.L.; Song, Y.Q.

2011-01-01

A systematic study of the hole transport and electrical properties in blue-emitting polymers as poly(9,9-dioctylfluorene) (PFO) has been performed. We show that the temperature dependent and thickness dependent current density versus voltage characteristics of PFO hole-only devices can be accurately described using our recently introduced improved mobility model based on both the Arrhenius temperature dependence and non-Arrhenius temperature dependence. Within the improved model, the mobility depends on three important physical quantities: temperature, carrier density, and electric field. For the polymer studied, we find the width of the density of states σ=0.115 eV and the lattice constant a=1.2 nm. Furthermore, we show that the boundary carrier density has an important effect on the current density versus voltage characteristics. Too large or too small values of the boundary carrier density lead to incorrect current density versus voltage characteristics. The numerically calculated carrier density is a decreasing function of distance from the interface. The numerically calculated electric field is an increasing function of distance. Both the maximum of carrier density and minimum of electric field appear near the interface.

Transport Properties of Bulk Thermoelectrics—An International Round-Robin Study, Part I: Seebeck Coefficient and Electrical Resistivity

Science.gov (United States)

Wang, Hsin; Porter, Wallace D.; Böttner, Harald; König, Jan; Chen, Lidong; Bai, Shengqiang; Tritt, Terry M.; Mayolet, Alex; Senawiratne, Jayantha; Smith, Charlene; Harris, Fred; Gilbert, Patricia; Sharp, Jeff W.; Lo, Jason; Kleinke, Holger; Kiss, Laszlo

2013-04-01

Recent research and development of high-temperature thermoelectric materials has demonstrated great potential for converting automobile exhaust heat directly into electricity. Thermoelectrics based on classic bismuth telluride have also started to impact the automotive industry by enhancing air-conditioning efficiency and integrated cabin climate control. In addition to engineering challenges of making reliable and efficient devices to withstand thermal and mechanical cycling, the remaining issues in thermoelectric power generation and refrigeration are mostly materials related. The dimensionless figure of merit, ZT, still needs to be improved from the current value of 1.0 to 1.5 to above 2.0 to be competitive with other alternative technologies. In the meantime, the thermoelectric community could greatly benefit from the development of international test standards, improved test methods, and better characterization tools. Internationally, thermoelectrics have been recognized by many countries as a key component for improving energy efficiency. The International Energy Agency (IEA) group under the Implementing Agreement for Advanced Materials for Transportation (AMT) identified thermoelectric materials as an important area in 2009. This paper is part I of the international round-robin testing of transport properties of bulk thermoelectrics. The main foci in part I are the measurement of two electronic transport properties: Seebeck coefficient and electrical resistivity.

Metallic electrical transport in inter-graphitic planes of an individual tubular carbon nanocone

Energy Technology Data Exchange (ETDEWEB)

Wang, Q; Gao, R X; Qu, S L [Department of Optics and Electronics Science, Harbin Institute of Technology at Wei Hai, Weihai 264209 (China); Li, J J; Gu, C Z [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080 (China)], E-mail: wq19750505@tom.com

2009-04-08

Tubular carbon cones (TCCs) with a herring-bone-like graphitic structure are synthesized on gold wire via the bias-assisted hot filament chemical vapor deposition (HFCVD) method. The electrical transport properties of an individual TCC are studied in the temperature range from 300 to 500 K by using a double probe scanning electron microscopy (DPSEM) in situ electrical measurement system. The high-resistance I-V characteristics of W-TCC-Au back-to-back double junctions show that electrons tunnel through the W-TCC junction, while thermoionic transport through the Au-TCC junction contributes to low-resistance properties. Temperature dependence of the electrical characteristics indicates that inter-graphitic-plane electrical transport in TCC is metallic.

Spin-dependent electrical transport in Fe-MgO-Fe heterostructures

Directory of Open Access Journals (Sweden)

A A Shokri

2016-09-01

Full Text Available In this paper, spin-dependent electrical transport properties are investigated in a single-crystal magnetic tunnel junction (MTJ which consists of two ferromagnetic Fe electrodes separated by an MgO insulating barrier. These properties contain electric current, spin polarization and tunnel magnetoresistance (TMR. For this purpose, spin-dependent Hamiltonian is described for Δ1 and Δ5 bands in the transport direction. The transmission is calculated by Green's function formalism based on a single-band tight-binding approximation. The transport properties are investigated as a function of the barrier thickness in the limit of coherent tunneling. We have demonstrated that dependence of the TMR on the applied voltage and barrier thickness. Our numerical results may be useful for designing of spintronic devices. The numerical results may be useful in designing of spintronic devices.

Subthreshold electrical transport in amorphous phase-change materials

International Nuclear Information System (INIS)

Gallo, Manuel Le; Kaes, Matthias; Sebastian, Abu; Krebs, Daniel

2015-01-01

Chalcogenide-based phase-change materials play a prominent role in information technology. In spite of decades of research, the details of electrical transport in these materials are still debated. In this article, we present a unified model based on multiple-trapping transport together with 3D Poole–Frenkel emission from a two-center Coulomb potential. With this model, we are able to explain electrical transport both in as-deposited phase-change material thin films, similar to experimental conditions in early work dating back to the 1970s, and in melt-quenched phase-change materials in nanometer-scale phase-change memory devices typically used in recent studies. Experimental measurements on two widely different device platforms show remarkable agreement with the proposed mechanism over a wide range of temperatures and electric fields. In addition, the proposed model is able to seamlessly capture the temporal evolution of the transport properties of the melt-quenched phase upon structural relaxation. (paper)

Effect of ambient on electrical transport properties of ultra-thin Au nanowires

Science.gov (United States)

Amin, Kazi Rafsanjani; Kundu, Subhajit; Biswas, Sangram; Roy, Ahin; Singh, Abhishek Kumar; Ravishankar, N.; Bid, Aveek

2016-12-01

In this letter we present systematic studies of the dynamics of surface adsorption of various chemicals on ultra-thin single crystalline gold nanowires (AuNW) through sensitive resistance fluctuation spectroscopy measurements coupled with ab initio simulations. We show that, contrary to expectations, the adsorption of common chemicals like methanol and acetone has a profound impact on the electrical transport properties of the AuNW. Our measurements and subsequent calculations establish conclusively that in AuNW, semiconductor-like sensitivity to the ambient arises because of changes induced in its local density of states by the surface adsorbed molecules. The extreme sensitivity of the resistance fluctuations of the AuNW to ambient suggests their possible use as solid-state sensors.

Investigation of electronic transport properties of some liquid transition metals

Science.gov (United States)

Patel, H. P.; Sonvane, Y. A.; Thakor, P. B.

2018-04-01

We investigated electronic transport properties of some liquid transition metals (V, Cr, Mn, Fe, Co and Pt) using Ziman formalism. Our parameter free model potential which is realized on ionic and atomic radius has been incorporated with the Hard Sphere Yukawa (HSY) reference system to study the electronic transport properties like electrical resistivity (ρ), thermal conductivity (σ) and thermo electrical power (Q). The screening effect on aforesaid properties has been studied by using different screening functions. The correlations of our results and others data with in addition experimental values are profoundly promising to the researchers working in this field. Also, we conclude that our newly constructed parameter free model potential is capable to explain the aforesaid electronic transport properties.

Impact of defects on the electrical transport, optical properties and failure mechanisms of GaN nanowires.

Energy Technology Data Exchange (ETDEWEB)

Armstrong, Andrew M.; Aubry, Sylvie; Shaner, Eric Arthur; Siegal, Michael P.; Li, Qiming; Jones, Reese E.; Westover, Tyler; Wang, George T.; Zhou, Xiao Wang; Talin, Albert Alec; Bogart, Katherine Huderle Andersen; Harris, C. Thomas; Huang, Jian Yu

2010-09-01

We present the results of a three year LDRD project that focused on understanding the impact of defects on the electrical, optical and thermal properties of GaN-based nanowires (NWs). We describe the development and application of a host of experimental techniques to quantify and understand the physics of defects and thermal transport in GaN NWs. We also present the development of analytical models and computational studies of thermal conductivity in GaN NWs. Finally, we present an atomistic model for GaN NW electrical breakdown supported with experimental evidence. GaN-based nanowires are attractive for applications requiring compact, high-current density devices such as ultraviolet laser arrays. Understanding GaN nanowire failure at high-current density is crucial to developing nanowire (NW) devices. Nanowire device failure is likely more complex than thin film due to the prominence of surface effects and enhanced interaction among point defects. Understanding the impact of surfaces and point defects on nanowire thermal and electrical transport is the first step toward rational control and mitigation of device failure mechanisms. However, investigating defects in GaN NWs is extremely challenging because conventional defect spectroscopy techniques are unsuitable for wide-bandgap nanostructures. To understand NW breakdown, the influence of pre-existing and emergent defects during high current stress on NW properties will be investigated. Acute sensitivity of NW thermal conductivity to point-defect density is expected due to the lack of threading dislocation (TD) gettering sites, and enhanced phonon-surface scattering further inhibits thermal transport. Excess defect creation during Joule heating could further degrade thermal conductivity, producing a viscous cycle culminating in catastrophic breakdown. To investigate these issues, a unique combination of electron microscopy, scanning luminescence and photoconductivity implemented at the nanoscale will be used in

Electric properties of weakly nonideal plasmas

Energy Technology Data Exchange (ETDEWEB)

Guenther, K; Radtke, R

1984-01-01

The progress in theory as well as in diagnostics and measurement during the last fifteen years is reviewed. Starting from the transport theory of ideal plasmas physically justified corrections are introduced which allow the quantitative calculation of the transport properties of weakly nonideal plasmas. Essential coefficients and numerical data of the electrical conductivity for plasmas of technical importance are given in tables and diagrams.

Electrical properties of dislocations in III-Nitrides

Energy Technology Data Exchange (ETDEWEB)

Cavalcoli, D.; Minj, A.; Pandey, S.; Cavallini, A. [Physics and Astronomy Dept. University of Bologna, Italy viale C Berti Pichat 6/II, Bologna (Italy)

2014-02-21

Research on GaN, AlN, InN (III-N) and their alloys is achieving new heights due their high potential applications in photonics and electronics. III-N semiconductors are mostly grown epitaxially on sapphire, and due to the large lattice mismatch and the differences in the thermal expansion coefficients, the structures usually contain many threading dislocations (TDs). While their structural properties have been widely investigated, their electrical characteristics and their role in the transport properties of the devices are still debated. In the present contribution we will show conductive AFM studies of TDs in GaN and Al/In GaN ternary alloys to evidence the role of strain, different surface polarity and composition on their electrical properties. Local I-V curves measured at TDs allowed us to clarify their role in the macroscopic electrical properties (leakage current, mobilities) of III-N based devices. Samples obtained by different growers (AIXTRON, III-V Lab) were studied. The comparison between the results obtained in the different alloys allowed us to understand the role of In and Al on the TDs electrical properties.

Electrical properties of dislocations in III-Nitrides

Science.gov (United States)

Cavalcoli, D.; Minj, A.; Pandey, S.; Cavallini, A.

2014-02-01

Research on GaN, AlN, InN (III-N) and their alloys is achieving new heights due their high potential applications in photonics and electronics. III-N semiconductors are mostly grown epitaxially on sapphire, and due to the large lattice mismatch and the differences in the thermal expansion coefficients, the structures usually contain many threading dislocations (TDs). While their structural properties have been widely investigated, their electrical characteristics and their role in the transport properties of the devices are still debated. In the present contribution we will show conductive AFM studies of TDs in GaN and Al/In GaN ternary alloys to evidence the role of strain, different surface polarity and composition on their electrical properties. Local I-V curves measured at TDs allowed us to clarify their role in the macroscopic electrical properties (leakage current, mobilities) of III-N based devices. Samples obtained by different growers (AIXTRON, III-V Lab) were studied. The comparison between the results obtained in the different alloys allowed us to understand the role of In and Al on the TDs electrical properties.

Bulk-Like Electrical Properties Induced by Contact-Limited Charge Transport in Organic Diodes: Revised Space Charge Limited Current

KAUST Repository

Xu, Guangwei

2018-02-22

Charge transport governs the operation and performance of organic diodes. Illuminating the charge-transfer/transport processes across the interfaces and the bulk organic semiconductors is at the focus of intensive investigations. Traditionally, the charge transport properties of organic diodes are usually characterized by probing the current–voltage (I–V) curves of the devices. However, to unveil the landscape of the underlying potential/charge distribution, which essentially determines the I–V characteristics, still represents a major challenge. Here, the electrical potential distribution in planar organic diodes is investigated by using the scanning Kelvin probe force microscopy technique, a method that can clearly separate the contact and bulk regimes of charge transport. Interestingly, by applying to devices based on novel, high mobility organic materials, the space-charge-limited-current-like I–V curves, which are previously believed to be a result of the bulk transport, are surprisingly but unambiguously demonstrated to be caused by contact-limited conduction. A model accounting is developed for the transport properties of both the two metal/organic interfaces and the bulk. The results indicate that pure interface-dominated transport can indeed give rise to I–V curves similar to those caused by bulk transport. These findings provide a new insight into the charge injection and transport processes in organic diodes.

Electrical conductivity and transport properties of cement-based materials measured by impedance spectroscopy

Science.gov (United States)

Shane, John David

The use of Impedance Spectroscopy (IS) as a tool to evaluate the electrical and transport properties of cement-based materials was critically evaluated. Emphasis was placed on determining the efficacy of IS by applying it as a tool to investigate several families of cement-based materials. Also, the functional aspects of electroding and null corrections were also addressed. The technique was found to be advantageous for these analyses, especially as a non-destructive, in-situ, rapid test. Moreover, key insights were gained into several cement-based systems (e.g., cement mortars and oil-well grouts) as well as the effect that certain testing techniques can have on materials (e.g., the rapid chloride permeability test). However, some limitations of IS were identified. For instance, improper electroding of samples can lead to erroneous results and incorrect interpretations for both two-point and multi-point measurements. This is an area of great importance, but it has received very little attention in the literature. Although the analysis of cement/electrode techniques is in its infancy, much progress was made in gaining a full understand of how to properly and reliably connect electrodes to cement-based materials. Through the application of IS to materials such as oil-well grouts, cement mortars and concretes, a great deal of valuable information about the effectiveness of IS has been gained. Oil-well cementing is somewhat limited by the inability to make measurements in the well-bore. By applying IS to oil-well grouts in a laboratory environment, it was demonstrated that IS is a viable technique with which to test the electrical and transport properties of these materials in-situ. Also, IS was shown to have the ability to measure the electrical conductivity of cement mortars with such accuracy, that very subtle changes in properties can be monitored and quantified. Through the use of IS and theoretical models, the complex interplay between the interfacial transition

Transport Properties in Nuclear Pasta

Science.gov (United States)

Caplan, Matthew; Horowitz, Charles; Berry, Donald; da Silva Schneider, Andre

2016-09-01

At the base of the inner crust of neutron stars, where matter is near the nuclear saturation density, nuclear matter arranges itself into exotic shapes such as cylinders and slabs, called `nuclear pasta.' Lepton scattering from these structures may govern the transport properties of the inner crust; electron scattering from protons in the pasta determines the thermal and electrical conductivity, as well as the shear viscosity of the inner crust. These properties may vary in pasta structures which form at various densities, temperatures, and proton fractions. In this talk, we report on our calculations of lepton transport in nuclear pasta and the implication for neutron star observables.

Node-node correlations and transport properties in scale-free networks

Science.gov (United States)

Obregon, Bibiana; Guzman, Lev

2011-03-01

We study some transport properties of complex networks. We focus our attention on transport properties of scale-free and small-world networks and compare two types of transport: Electric and max-flow cases. In particular, we construct scale-free networks, with a given degree sequence, to estimate the distribution of conductances for different values of assortative/dissortative mixing. For the electric case we find that the distributions of conductances are affect ed by the assortative mixing of the network whereas for the max-flow case, the distributions almost do not show changes when node-node correlations are altered. Finally, we compare local and global transport in terms of the average conductance for the small-world (Watts-Strogatz) model

Intrinsic and extrinsic electrical and thermal transport of bulk black phosphorus

Science.gov (United States)

Hu, Sile; Xiang, Junsen; Lv, Meng; Zhang, Jiahao; Zhao, Hengcan; Li, Chunhong; Chen, Genfu; Wang, Wenhong; Sun, Peijie

2018-01-01

We report a comprehensive investigation of the electrical, thermal, and thermoelectric transport properties of bulk single-crystalline black phosphorus in wide temperature (2-300 K) and field (0-9 T) ranges. Electrical transport below T ≈ 250 K is found to be dominated by extrinsic hole-type charge carriers with large mobility exceeding 104 cm2/V s at low temperatures. While thermal transport measurements reveal an enhanced in-plane thermal conductivity maximum κ = 180 W/m K at T ≈ 25 K, it appears still to be largely constrained by extrinsic phonon scattering processes, e.g., the electron-phonon process, in addition to intrinsic umklapp scattering. The thermoelectric power and Nernst effect seem to be strongly influenced by ambipolar transport of charge carriers with opposite signs in at least the high-temperature region above 200 K, which diminishes the thermoelectric power factor of this material. Our results provide a timely update to the transport properties of bulk black phosphorus for future fundamental and applied research.

Improving the electrical properties of graphene layers by chemical doping

International Nuclear Information System (INIS)

Khan, Muhammad Farooq; Iqbal, Muhammad Zahir; Iqbal, Muhammad Waqas; Eom, Jonghwa

2014-01-01

Although the electronic properties of graphene layers can be modulated by various doping techniques, most of doping methods cost degradation of structural uniqueness or electrical mobility. It is matter of huge concern to develop a technique to improve the electrical properties of graphene while sustaining its superior properties. Here, we report the modification of electrical properties of single- bi- and trilayer graphene by chemical reaction with potassium nitrate (KNO 3 ) solution. Raman spectroscopy and electrical transport measurements showed the n-doping effect of graphene by KNO 3 . The effect was most dominant in single layer graphene, and the mobility of single layer graphene was improved by the factor of more than 3. The chemical doping by using KNO 3 provides a facile approach to improve the electrical properties of graphene layers sustaining their unique characteristics. (paper)

An investigation on high-temperature electrical transport properties of graphene-oxide nano-thinfilms

International Nuclear Information System (INIS)

Venugopal, Gunasekaran; Krishnamoorthy, Karthikeyan; Kim, Sang-Jae

2013-01-01

High-temperature electrical transport properties are investigated for graphene-oxide nano thinfilms. The graphene-oxide nanoparticles are synthesized by modified Hummers method and characterized by UV–vis, Raman and X-ray diffraction techniques. The surface morphology of graphene-oxide film is analyzed using scanning electron and atomic force microscopy. The experimental results on high-temperature electrical studies of thinfilms exhibit metallic behavior followed by three-dimensional variable range hopping mechanism. The current–voltage characteristics at various temperatures (from 293 K to 573 K) were investigated. The effect of high-temperature on the functional groups of graphene-oxide film is evidently examined using X-ray photoelectron, thermal gravimetric analysis and Fourier transform infra-red spectroscopy. Transistor characteristics were performed after heat treatment resulting ambipolar behavior with holes and electron mobility of 127 and 66.9 cm 2 V −1 s −1 respectively. Our results are comparable to reduced graphene-oxide, indicating the advantage of our approach requires no further reduction to develop graphene-based transparent and conductive electrodes for dye-sensitized solar cells and ultra-capacitor applications.

Electrical Transport Properties of Polycrystalline Monolayer Molybdenum Disulfide

Science.gov (United States)

2014-07-14

Lou, Sina Najmaei, Matin Amani, Matthew L. Chin, Zheng Se. TASK NUMBER Liu Sf. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAMES AND ADDRESSES 8...Transport Properties of Polycrystalline Monolayer Molybdenum Disulfide Sina Najmaei,t.§ Matin Ama ni,M Matthew L. Chin,* Zhe ng liu/ ·"·v: A. Gle n

Electrical properties of molecular crystals; Proprietes electriques des cristaux moleculaires

Energy Technology Data Exchange (ETDEWEB)

Barraud, A [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1968-07-01

This literature survey summarizes the electrical properties of molecular crystals: molecular crystal structure, transport and excitation mechanisms of charge-carriers, and differences compared to inorganic semi-conductors. The main results concerning the electrical conductivity of the most-studied molecular crystals are presented, together with the optical and photo-electrical properties of these crystals. Finally the different types of electrical measurements used are reviewed, as well as the limits of each method. (author) [French] Cette etude bibliographique resume les proprietes electriques des cristaux moleculaires: structure des cristaux moleculaires, mecanismes de transport et d'excitation des porteurs de charge et differences avec les semiconducteurs mineraux. Les principaux resultats sur la conductibilite electrique des cristaux moleculaires les plus etudies y sont exposes, ainsi que les proprietes optiques et photoelectriques de ces cristaux. Enfin les differents types de mesures electriques utilisees sont passees en revue ainsi que les limites de chaque methode. (auteur)

Electrical properties of molecular crystals; Proprietes electriques des cristaux moleculaires

Energy Technology Data Exchange (ETDEWEB)

Barraud, A. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1968-07-01

This literature survey summarizes the electrical properties of molecular crystals: molecular crystal structure, transport and excitation mechanisms of charge-carriers, and differences compared to inorganic semi-conductors. The main results concerning the electrical conductivity of the most-studied molecular crystals are presented, together with the optical and photo-electrical properties of these crystals. Finally the different types of electrical measurements used are reviewed, as well as the limits of each method. (author) [French] Cette etude bibliographique resume les proprietes electriques des cristaux moleculaires: structure des cristaux moleculaires, mecanismes de transport et d'excitation des porteurs de charge et differences avec les semiconducteurs mineraux. Les principaux resultats sur la conductibilite electrique des cristaux moleculaires les plus etudies y sont exposes, ainsi que les proprietes optiques et photoelectriques de ces cristaux. Enfin les differents types de mesures electriques utilisees sont passees en revue ainsi que les limites de chaque methode. (auteur)

Effects of pressure and electrical charge on macromolecular transport across bovine lens basement membrane.

Science.gov (United States)

Ferrell, Nicholas; Cameron, Kathleen O; Groszek, Joseph J; Hofmann, Christina L; Li, Lingyan; Smith, Ross A; Bian, Aihua; Shintani, Ayumi; Zydney, Andrew L; Fissell, William H

2013-04-02

Molecular transport through the basement membrane is important for a number of physiological functions, and dysregulation of basement membrane architecture can have serious pathological consequences. The structure-function relationships that govern molecular transport in basement membranes are not fully understood. The basement membrane from the lens capsule of the eye is a collagen IV-rich matrix that can easily be extracted and manipulated in vitro. As such, it provides a convenient model for studying the functional relationships that govern molecular transport in basement membranes. Here we investigate the effects of increased transmembrane pressure and solute electrical charge on the transport properties of the lens basement membrane (LBM) from the bovine eye. Pressure-permeability relationships in LBM transport were governed primarily by changes in diffusive and convective contributions to solute flux and not by pressure-dependent changes in intrinsic membrane properties. The solute electrical charge had a minimal but statistically significant effect on solute transport through the LBM that was opposite of the expected electrokinetic behavior. The observed transport characteristics of the LBM are discussed in the context of established membrane transport modeling and previous work on the effects of pressure and electrical charge in other basement membrane systems. Copyright © 2013 Biophysical Society. Published by Elsevier Inc. All rights reserved.

Thermoelectric transport properties of BaBiTe{sub 3}-based materials

Energy Technology Data Exchange (ETDEWEB)

Zhou, Yiming; Zhao, Li-Dong, E-mail: zhaolidong@buaa.edu.cn

2017-05-15

BaBiTe{sub 3}, a material with low thermal conductivity, is an inferior thermoelectric material due to the poor electrical properties originated from its narrow band gap. We choose two types of dopants, K and La, trying to optimize its electrical transport properties. The minority carriers, which harm the Seebeck coefficient in this system, are suppressed by La doping. With the increase of both electrical conductivity and Seebeck coefficient, the power factor of 3% La doped BaBiTe{sub 3} reaches 3.7 μW cm{sup −1} K{sup −2} which increased by 40% from undoped BaBiTe{sub 3}. Besides high power factor, the thermal conductivity is also reduced in it. Eventually, a high ZT value, 0.25 at 473 K, for n-type BaBiTe{sub 3} is achieved in 3% La doped BaBiTe{sub 3}. - Graphical abstract: BaBiTe{sub 3} possesses a low thermal conductivity. However, it is an inferior thermoelectric material due to the poor electrical properties originated from its narrow band gap. A high ZT value of 0.25 at 473 K for n-type BaBiTe{sub 3} can be achieved through optimizing electrical transport properties via La doping. - Highlights: • BaBiTe{sub 3} is an analogue of these promising thermoelectric materials: such as CsBi{sub 4}Te{sub 6} and K{sub 2}Bi{sub 8}Se{sub 13}, etc. • BaBiTe{sub 3} possesses a low thermal conductivity. • La is an effective dopant to enhance electrical transport properties. • A high ZT value of 0.25 at 473 K can be achieved in n-type La-doped BaBiTe{sub 3}.

Charge carrier transport properties in layer structured hexagonal boron nitride

Directory of Open Access Journals (Sweden)

T. C. Doan

2014-10-01

Full Text Available Due to its large in-plane thermal conductivity, high temperature and chemical stability, large energy band gap (˜ 6.4 eV, hexagonal boron nitride (hBN has emerged as an important material for applications in deep ultraviolet photonic devices. Among the members of the III-nitride material system, hBN is the least studied and understood. The study of the electrical transport properties of hBN is of utmost importance with a view to realizing practical device applications. Wafer-scale hBN epilayers have been successfully synthesized by metal organic chemical deposition and their electrical transport properties have been probed by variable temperature Hall effect measurements. The results demonstrate that undoped hBN is a semiconductor exhibiting weak p-type at high temperatures (> 700 °K. The measured acceptor energy level is about 0.68 eV above the valence band. In contrast to the electrical transport properties of traditional III-nitride wide bandgap semiconductors, the temperature dependence of the hole mobility in hBN can be described by the form of μ ∝ (T/T0−α with α = 3.02, satisfying the two-dimensional (2D carrier transport limit dominated by the polar optical phonon scattering. This behavior is a direct consequence of the fact that hBN is a layer structured material. The optical phonon energy deduced from the temperature dependence of the hole mobility is ħω = 192 meV (or 1546 cm-1, which is consistent with values previously obtained using other techniques. The present results extend our understanding of the charge carrier transport properties beyond the traditional III-nitride semiconductors.

Structural and electrical transport properties of La2Mo2O9 thin films prepared by pulsed laser deposition

Science.gov (United States)

Paul, T.; Ghosh, A.

2017-04-01

We have studied the structure and electrical properties of La2Mo2O9 thin films of different thicknesses prepared by the laser deposition technique at different substrate temperatures. The structural properties of the thin films have been investigated using XRD, XPS, AFM, TEM, SEM, and Raman spectroscopy. The electrical transport properties of the thin films have been investigated in wide temperature and frequency ranges. The cubic nature of the thin films has been confirmed from structural analysis. An enhancement of the oxygen ion conductivity of the films up to five orders of magnitude is obtained compared to that of the bulk La2Mo2O9, suggesting usefulness of the thin films as electrolytes in micro-solid oxide fuel cells. The enhanced dc ionic conductivity of the thin films has been interpreted using the rule of the mixture model, while a power law model has been used to investigate the frequency and temperature dependences of the conductivity. The analysis of the results predicts the three-dimensional oxygen ion conduction in the thin films.

B₁₂P₂: Improved Epitaxial Growth and Evaluation of Alpha Irradiation on its Electrical Transport Properties

Energy Technology Data Exchange (ETDEWEB)

Frye, Clint D. [Kansas State Univ., Manhattan, KS (United States)

2016-10-17

The wide bandgap (3.35 eV) semiconductor icosahedral boron phosphide (B₁₂P₂) has been reported to self-heal from radiation damage from β particles (electrons) with energies up to 400 keV by demonstrating no lattice damage using transmission electron microscopy. This property could be exploited to create radioisotope batteries–semiconductor devices that directly convert the decay energy from a radioisotope to electricity. Such devices potentially have enormous power densities and decades-long lifetimes. To date, the radiation hardness of B₁₂P₂ has not been characterized by electrical measurements nor have B₁₂P₂ radioisotope batteries been realized. Therefore, this study was undertaken to evaluate the radiation hardness of B₁₂P₂ after improving its epitaxial growth, developing ohmic electrical contacts, and reducing the residual impurities. Subsequently, the effects of radiation from a radioisotope on the electrical transport properties of B₁₂P₂ were tested.

Tariff structures for the transport of electricity

International Nuclear Information System (INIS)

Frenken, R.M.L.; Van de Water, C.J.

1995-01-01

Some possible tariff structures for electricity transport are discussed. First, the costs associated with the transport of electricity are explained. The fixed and variable costs of a transport are illustrated with some examples. Furthermore, the most common tariff structures (contract path, megawatt mile, postage stamp) and negotiated Third Party Access are discussed. Finally, the way the tariff structures reflect the costs of electricity transport are reviewed. 3 figs., 1 tab., 7 refs

Electrical transport properties study of Mo{sub 0.6}W{sub 0.4}Se{sub 2} single crystals

Energy Technology Data Exchange (ETDEWEB)

Chaki, Sunil; Deshpande, M. P.; Tailor, J. P.; Chaudhary, M. D.; Sakaria, Pallavi N. [Department of Physics, Sardar Patel University, Vallabh Vidyanagar, Gujarat-388120 (India)

2012-06-05

The mixed transition metal dichalcogenide single crystals Mo{sub 0.6}W{sub 0.4}Se{sub 2} were characterized employing EDAX (Energy Dispersive Analysis of X-ray), (XRD) X-ray diffraction, SEM (Scanning Electron Microscope) and UV-Vis-NIR spectroscopy techniques. The electrical transport properties of as-grown Mo{sub 0.6}W{sub 0.4}Se{sub 2} single crystals were studied by two probe d. c. resistivity, Hall Effect and thermoelectric power measurement set-up. The obtained results are discussed in details.

Effect of annealing temperature on the electrical transport properties of CaRuO3-δ thin films directly deposited on the Si substrate

International Nuclear Information System (INIS)

Paik, Hanjong; Kim, Youngha; No, Kwangsoo; Cann, David P.; Yoon, DongJoo; Kim, ByungIl; Kim, Yangsoo

2007-01-01

We investigate the effect of annealing temperature on the preferentially (110)-oriented CaRuO 3-δ (CRO) thin films directly prepared on Si(100) substrate by rf magnetron sputtering. Crystalline quality and electrical transport properties of the CRO thin films were modified by post-annealing treatment. It was obvious that 700 C post-annealing brought about excellent metallic characteristics with the elevation of carrier concentration and mobility. From this result, we suggested that enhanced (110) orientation, and the ratio of chemical composition Ru 4+ /Ca 2+ ion were responsible for the transport properties of CRO thin film. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Magnetic and Electrical Transport Properties of Dirac Compound BaMnSb2*

Science.gov (United States)

Huang, Silu; Kim, Jisun; Shelton, William. A.; Plummer, Ward; Jin, Rongying

BaMnSb2 is a layered compound containing Sb square nets that is theoretically predicted to host Dirac fermions. We have carried out experimental investigations on electrical transport and magnetic properties of BaMnSb2 single crystals. Both in-plane (ρab) and c-axis (ρc) resistivities show metallic behavior with a small bump in ρc located near 40 K, while there is large anisotropy ρc / ρab ( 100 at 300 K) that increases with decreasing temperature to 1500 at 2 K. Interestingly, Shubnikov-de Hass (SdH) oscillations are observed for both ρab and ρc over a wide temperature and magnetic field range. Quantitative analysis indicates that large amplitude SdH oscillations result from nearly massless Dirac Fermions. Furthermore, our magnetic measurements indicate an A-type antiferromagnetic magnetic ordering below 286 K where ferromagnetic ordering is observed in the ab plane with antiferromagnetic coupling along the c direction. These results indicate that BaMnSb2 is a 2D magnetic Dirac material. This work is supported by NSF through Grant Number DMR-1504226.

Disorder controlled electrical transport properties of NdCo1−xNiO3

International Nuclear Information System (INIS)

Kumar, Vinod; Kumar, Rajesh; Shukla, D.K.; Kumar, Ravi

2013-01-01

Highlights: •Single phase NdCo 1−x Ni x O 3 were prepared using solid state reaction method. •Drastic improvement in room temperature conductivity for substituted samples. •Arrhenius and VRH conduction models employed to explain electrical transport. •Disorder induced charge carrier localization dominates in the substituted samples. -- Abstract: The effect of Ni substitution on structural and electrical transport has been investigated in NdCo 1−x Ni x O 3 system for 0 ⩽ x ⩽ 0.5. The Rietveld refinement of XRD data confirms orthorhombic, Pbnm symmetry for all the samples. The lattice parameters and hence unit cell volume is found to increase linearly with increase in Ni concentration. Substitution of Ni leads to the increase in conductivity and samples have been found to display semiconducting behavior in measured range of temperature. The explanation for the variation of resistivity with substitution and temperature has been provided on the basis of substitutional disorder and spin state related effects. Arrhenius and variable range hopping conduction approaches have been used to explain the temperature variation of resistivity. These results suggest that disorder-induced localization of charge carriers dominate the electrical transport in the substituted samples

Calculations of the transport properties within the PAW formalism

Energy Technology Data Exchange (ETDEWEB)

Mazevet, S.; Torrent, M.; Recoules, V.; Jollet, F. [CEA Bruyeres-le-Chatel, DIF, 91 (France)

2010-07-01

We implemented the calculation of the transport properties within the PAW formalism in the ABINIT code. This feature allows the calculation of the electrical and optical properties, including the XANES spectrum, as well as the electronic contribution to the thermal conductivity. We present here the details of the implementation and results obtained for warm dense aluminum plasma. (authors)

Electronic transport properties of 4f shell elements of liquid metal using hard sphere Yukawa system

Science.gov (United States)

Patel, H. P.; Sonvane, Y. A.; Thakor, P. B.

2018-04-01

The electronic transport properties are analyzed for 4f shell elements of liquid metals. To examine the electronic transport properties like electrical resistivity (ρ), thermal conductivity (σ) and thermo electrical power (Q), we used our own parameter free model potential with the Hard Sphere Yukawa (HSY) reference system. The screening effect on aforesaid properties has been examined by using different screening functions like Hartree (H), Taylor (T) and Sarkar (S). The correlations of our resultsand other data with available experimental values are intensely promising. Also, we conclude that our newly constructed parameter free model potential is capable of explaining the above mentioned electronic transport properties.

Dynamical interplay between fluctuations, electric fields and transport in fusion plasmas

International Nuclear Information System (INIS)

Hidalgo, C.; Pedrosa, M.A.; Goncalves, B.

2003-01-01

A view of recent experimental results and progress in the characterization of the statistical properties of electrostatic turbulence in magnetically confined devices is given. An empirical similarity in the scaling properties of the probability distribution function (PDF) of turbulent transport has been observed in the plasma edge region in fusion plasmas. The investigation of the dynamical interplay between fluctuation in gradients, turbulent transport and radial electric fields has shows that these parameters are strongly coupled both in tokamak and stellarator plasmas. The bursty behaviour of turbulent transport is linked with a departure from the most probable radial gradient. The dynamical relation between fluctuations in gradients and transport is strongly affected by the presence of sheared poloidal flows which organized themselves near marginal stability. These results emphasize the importance of the statistical description of transport processes in fusion plasmas as an alternative approach to the traditional way to characterize transport based on the computation of effective transport coefficients. (author)

Transport properties of Dirac electrons in graphene based double velocity-barrier structures in electric and magnetic fields

International Nuclear Information System (INIS)

Liu, Lei; Li, Yu-Xian; Liu, Jian-Jun

2012-01-01

Using transfer matrix method, transport properties in graphene based double velocity-barrier structures under magnetic and electric fields are numerically studied. It is found that velocity barriers for the velocity ratio (the Fermi velocity inside the barrier to that outside the barrier) less than one (or for the velocity ratio greater than one) have properties similar to electrostatic wells (or barriers). The velocity barriers for the velocity ratio greater than one significantly enlarge the resonant tunneling region of electrostatic barriers. In the presence of magnetic field, the plateau width of the Fano factor with a Poissonian value shortens (or broadens) for the case of the velocity ratio less than one (or greater than one). When the Fermi energy is equal to the electrostatic barrier height, for different values of the velocity ratio, both the conductivities and the Fano factors remain fixed. -- Highlights: ► We model graphene based velocity-barrier structures in electric and magnetic fields. ► Velocity barrier for ξ 1) have property similar to electrostatic well (barrier). ► Velocity barrier for ξ>1 enlarge the resonant tunneling region of electrostatic barrier. ► The plateau width of Fano factor shortens (or broadens) for the case of ξ 1). ► The conductivity remains fixed at the point of E F =U 0 for different values of ξ.

Electrical properties and transport mechanisms in phase change memory thin films of quasi-binary-line GeTe–Sb{sub 2}Te{sub 3} chalcogenide semiconductors

Energy Technology Data Exchange (ETDEWEB)

Sherchenkov, A. A. [National Research University of Electronic Technology (Russian Federation); Kozyukhin, S. A., E-mail: sergkoz@igic.ras.ru [Russian Academy of Sciences, Kurnakov Institute of General and Inorganic Chemistry (Russian Federation); Lazarenko, P. I.; Babich, A. V. [National Research University of Electronic Technology (Russian Federation); Bogoslovskiy, N. A. [Russian Academy of Sciences, Ioffe Physical–Technical Institute (Russian Federation); Sagunova, I. V.; Redichev, E. N. [National Research University of Electronic Technology (Russian Federation)

2017-02-15

The temperature dependences of the resistivity and current–voltage (I–V) characteristics of phase change memory thin films based on quasi-binary-line GeTe–Sb{sub 2}Te{sub 3} chalcogenide semiconductors Ge{sub 2}Sb{sub 2}Te{sub 5}, GeSb{sub 2}Te{sub 5}, and GeSb{sub 4}Te{sub 7} are investigated. The effect of composition variation along the quasibinary line on the electrical properties and transport mechanisms of the thin films is studied. The existence of three ranges with different I–V characteristics is established. The position and concentration of energy levels controlling carrier transport are estimated. The results obtained show that the electrical properties of the thin films can significantly change during a shift along the quasi-binary line GeTe–Sb{sub 2}Te{sub 3}, which is important for targeted optimization of the phase change memory technology.

Electrical properties of ZnO nanorods and layers

Energy Technology Data Exchange (ETDEWEB)

Schlenker, Eva; Bakin, Andrey; Peters, Ole; Mofor, Augustine C.; Postels, Bianca; El-Shaer, Hamid; Wehmann, Hergo-Heinrich; Waag, Andreas [Institut fuer Halbleitertechnik, TU Braunschweig (Germany); Weimann, Thomas; Hinze, Peter [Physikalisch-Technische Bundesanstalt (PTB), Braunschweig (Germany)

2007-07-01

ZnO has attracted a lot of interest in the scientific community due to its outstanding properties. With a band gap of 3.37 eV and an exciton binding energy of 60 meV it is a promising candidate for micro- and optoelectronic applications. The growth of ZnO nanostructures and epitaxial layers is well under control and their optical and structural properties are already thoroughly characterized. However, due to contacting difficulties, less reports exist on the electrical properties of single ZnO nanostructures. In this contribution we present various contacting methods in order to explore the electrical properties of individual nanorods either grown by aqueous chemical growth or vapor phase transport. Current-Voltage characteristics were obtained by using an atomic force microscope with a conductive tip or by patterning contacts with e-beam lithography. The results are compared to the ones obtained from measurements on epitaxially grown ZnO layers and first applications are presented.

Antimony doped cadmium selenium nanobelts with enhanced electrical and optoelectrical properties

Energy Technology Data Exchange (ETDEWEB)

Zhang, Lijie [National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai 200083 (China); Nanomaterials and Chemistry Key Laboratory, Wenzhou University, Wenzhou 325027 (China); Yu, Hongfei; Cao, Wei; Dong, Youqing; Zou, Chao; Yang, Yun [Nanomaterials and Chemistry Key Laboratory, Wenzhou University, Wenzhou 325027 (China); Huang, Shaoming, E-mail: smhuang@wzu.edu.cn [Nanomaterials and Chemistry Key Laboratory, Wenzhou University, Wenzhou 325027 (China); Dai, Ning [National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai 200083 (China); Zhu, Da-Ming, E-mail: ZhuD@umkc.edu [National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai 200083 (China); University of Missouri-Kansas City, Kansas City, MO 64110 (United States)

2014-07-01

Intrinsic and Sb-doped CdSe nanobelts (NBs) were synthesized via a thermal evaporation technique. The electrical transport properties of field effect transistors (FETs) fabricated using the NBs were investigated. The results indicate that the Sb-doped NBs behave as n-type semiconductors with improved electrical conductivity (10⁻¹ to 100 S/cm) compared with the intrinsic CdSe. Photodetectors made of single NB were also fabricated and investigated. The results show that Sb-doped NB photodetectors exhibit much higher responsivity (1.5 × 10⁴ A/W) and external quantum efficiency (1.2 × 10⁵) but lower on/off current ratio (~253) and longer response time (≤40 ms). Furthermore, both electrical transport and optoelectrical properties of the as-synthesized CdSe NBs can be tuned by changing the doping concentration. The results indicate that the as-synthesized NBs are excellent building blocks for constructing electronic and optoelectronic devices.

The effect of gate voltage on the electrical transport properties in the contacts of C60 to carbon nanotube leads

Directory of Open Access Journals (Sweden)

AA Shokri

2012-06-01

Full Text Available  In this paper, we examined the effect of gate voltage, bias voltage, contact geometries and the different bond lengths on the electrical transport properties in a nanostructure consisting of C60 molecule attached to two semi-infinite leads made of single wall carbon nanotubes in the coherent regime. Our calculation was based on the Green’s function method within nearest-neighbour tight-binding approximation. After the calculation was of transmission, the electrical current was obtained by the Landauer-Buttiker formula. Next, the effect of the mentioned factors was investigated in the nanostructure. The application of the present results may be useful in designing devices based on molecular electronics in nanoscale.

Electrical transport and optical band gap of NiFe2Ox thin films

Science.gov (United States)

Bougiatioti, Panagiota; Manos, Orestis; Klewe, Christoph; Meier, Daniel; Teichert, Niclas; Schmalhorst, Jan-Michael; Kuschel, Timo; Reiss, Günter

2017-12-01

We fabricated NiFe2Ox thin films on MgAl2O4(001) by reactive dc magnetron co-sputtering varying the oxygen partial pressure. The fabrication of a material with a variable oxygen deficiency leads to controllable electrical and optical properties which are beneficial for the investigations of the transport phenomena and could, therefore, promote the use of such materials in spintronic and spin caloritronic applications. We used several characterization techniques to investigate the film properties, focusing on their structural, magnetic, electrical, and optical properties. From the electrical resistivity, we obtained the conduction mechanisms that govern the systems in the high and low temperature regimes. We further extracted low thermal activation energies which unveil extrinsic transport mechanisms. The thermal activation energy decreases in the less oxidized samples revealing the pronounced contribution of a large amount of electronic states localized in the band gap to the electrical conductivity. The Hall coefficient is negative and decreases with increasing conductivity as expected for n-type conduction, while the Hall- and the drift mobilities show a large difference. The optical band gaps were determined via ultraviolet-visible spectroscopy. They follow a similar trend as the thermal activation energies, with lower band gap values in the less oxidized samples.

Nonlinear electrical properties of Si three-terminal junction devices

DEFF Research Database (Denmark)

Fantao, Meng; Jie, Sun; Graczyk, Mariusz

2010-01-01

This letter reports on the realization and characterization of silicon three-terminal junction devices made in a silicon-on-insulator wafer. Room temperature electrical measurements show that the fabricated devices exhibit pronounced nonlinear electrical properties inherent to ballistic electron...... transport in a three-terminal ballistic junction (TBJ) device. The results show that room temperature functional TBJ devices can be realized in a semiconductor material other than high-mobility III-V semiconductor heterostructures and provide a simple design principle for compact silicon devices...

Electricity: an indigenous transport fuel

Energy Technology Data Exchange (ETDEWEB)

Byers, D J

1978-12-25

Potential reserves of hydro and geothermal power are adequate to power all road-transport vehicles should these be converted to electric drives in the future. Conversion of petrol vehicles to electric drives results in a significant increase in energy-utilization efficiency coupled with a decrease in costs, both to the country in overseas funds and to the driver in operating costs. As yet, however, New Zealand has no plan to use these resources in a transport role and is supporting no feasibility research.

Electrical transport and pinning properties of Nb thin films patterned with focused ion beam-milled washboard nanostructures

International Nuclear Information System (INIS)

Dobrovolskiy, O V; Begun, E; Huth, M; Shklovskij, V A

2012-01-01

A careful analysis of the magneto-transport properties of epitaxial nanostructured Nb thin films in the normal and the mixed state is performed. The nanopatterns were prepared by focused ion beam (FIB) milling. They provide a washboard-like pinning potential landscape for vortices in the mixed state and simultaneously cause a resistivity anisotropy in the normal state. Two matching magnetic fields for the vortex lattice with the underlying nanostructures have been observed. By applying these fields, the most likely pinning sites along which the flux lines move through the samples have been selected. By this, either the background isotropic pinning of the pristine film or the enhanced isotropic pinning originating from the nanoprocessing have been probed. Via an Arrhenius analysis of the resistivity data the pinning activation energies for three vortex lattice parameters have been quantified. The changes in the electrical transport and the pinning properties have been correlated with the results of the microstructural and topographical characterization of the FIB-patterned samples. Accordingly, along with the surface processing, FIB milling has been found to alter the material composition and the degree of disorder in as-grown films. The obtained results provide further insight into the pinning mechanisms at work in FIB-nanopatterned superconductors, e.g. for fluxonic applications. (paper)

Electrical transport properties of an isolated CdS microrope composed of twisted nanowires

OpenAIRE

Yu, Gui-Feng; Yu, Miao; Pan, Wei; Han, Wen-Peng; Yan, Xu; Zhang, Jun-Cheng; Zhang, Hong-Di; Long, Yun-Ze

2015-01-01

CdS is one of the important II-VI group semiconductors. In this paper, the electrical transport behavior of an individual CdS microrope composed of twisted nanowires is studied. It is found that the current?voltage (I-V) characteristics show two distinct power law regions from 360 down to 60?K. Space-charge-limited current (SCLC) theory is used to explain these temperature- and electric-field-dependent I-V curves. The I-V data can be well fitted by this theory above 100?K, and the correspondi...

Modeling the transport properties of epitaxially grown thermoelectric oxide thin films using spectroscopic ellipsometry

KAUST Repository

Sarath Kumar, S. R.

2012-02-01

The influence of oxygen vacancies on the transport properties of epitaxial thermoelectric (Sr,La)TiO3 thin films is determined using electrical and spectroscopic ellipsometry (SE) measurements. Oxygen vacancy concentration was varied by ex-situ annealing in Ar and Ar/H2. All films exhibited degenerate semiconducting behavior, and electrical conductivity decreased (258–133 S cm−1) with increasing oxygen content. Similar decrease in the Seebeck coefficient is observed and attributed to a decrease in effective mass (7.8–3.2 me ), as determined by SE. Excellent agreement between transport properties deduced from SE and direct electrical measurements suggests that SE is an effective tool for studying oxide thin film thermoelectrics.

Modeling the transport properties of epitaxially grown thermoelectric oxide thin films using spectroscopic ellipsometry

KAUST Repository

Sarath Kumar, S. R.; Abutaha, Anas I.; Hedhili, Mohamed N.; Alshareef, Husam N.

2012-01-01

The influence of oxygen vacancies on the transport properties of epitaxial thermoelectric (Sr,La)TiO3 thin films is determined using electrical and spectroscopic ellipsometry (SE) measurements. Oxygen vacancy concentration was varied by ex-situ annealing in Ar and Ar/H2. All films exhibited degenerate semiconducting behavior, and electrical conductivity decreased (258–133 S cm−1) with increasing oxygen content. Similar decrease in the Seebeck coefficient is observed and attributed to a decrease in effective mass (7.8–3.2 me ), as determined by SE. Excellent agreement between transport properties deduced from SE and direct electrical measurements suggests that SE is an effective tool for studying oxide thin film thermoelectrics.

Elastic properties and electron transport in InAs nanowires

Energy Technology Data Exchange (ETDEWEB)

Migunov, Vadim

2013-02-22

The electron transport and elastic properties of InAs nanowires grown by chemical vapor deposition on InAs (001) substrate were studied experimentally, in-situ in a transmission electron microscope (TEM). A TEM holder allowing the measurement of a nanoforce while simultaneous imaging nanowire bending was used. Diffraction images from local areas of the wire were recorded to correlate elastic properties with the atomic structure of the nanowires. Another TEM holder allowing the application of electrical bias between the nanowire and an apex of a metallic needle while simultaneous imaging the nanowire in TEM or performing electron holography was used to detect mechanical vibrations in mechanical study or holographical observation of the nanowire inner potential in the electron transport studies. The combination of the scanning probe methods with TEM allows to correlate the measured electric and elastic properties of the nanowires with direct identification of their atomic structure. It was found that the nanowires have different atomic structures and different stacking fault defect densities that impacts critically on the elastic properties and electric transport. The unique methods, that were applied in this work, allowed to obtain dependencies of resistivity and Young's modulus of left angle 111 right angle -oriented InAs nanowires on defect density and diameter. It was found that the higher is the defect density the higher are the resistivity and the Young's modulus. Regarding the resistivity, it was deduced that the stacking faults increase the scattering of the electrons in the nanowire. These findings are consistent with the literature, however, the effect described by the other groups is not so pronounced. This difference can be attributed to the significant incompleteness of the physical models used for the data analysis. Regarding the elastic modulus, there are several mechanisms affecting the elasticity of the nanowires discussed in the thesis. It

Magneto-electrical transport through MBE-grown III-V semiconductor nanostructures. From zero- to one-dimensional type of transport

International Nuclear Information System (INIS)

Storace, Eleonora

2009-01-01

From the development of the first transistor in 1947, great interest has been directed towards the technological development of semiconducting devices and the investigation of their physical properties. A very vital field within this topic focuses on the electrical transport through low-dimensional structures, where the quantum confinement of charge carriers leads to the observation of a wide variety of phenomena that, in their turn, can give an interesting insight on the fundamental properties of the structures under examination. In the present thesis, we will start analyzing zero-dimensional systems, focusing on how electrons localized onto an island can take part in the transport through the whole system; by precisely tuning the tunnel coupling strength between this island and its surroundings, we will then show how it is possible to move from a zero- to a one-dimensional system. Afterwards, the inverse path will be studied: a one-dimensional system is electrically characterized, proving itself to split up due to disorder into several zero-dimensional structures. (orig.)

Magneto-electrical transport through MBE-grown III-V semiconductor nanostructures. From zero- to one-dimensional type of transport

Energy Technology Data Exchange (ETDEWEB)

Storace, Eleonora

2009-07-08

From the development of the first transistor in 1947, great interest has been directed towards the technological development of semiconducting devices and the investigation of their physical properties. A very vital field within this topic focuses on the electrical transport through low-dimensional structures, where the quantum confinement of charge carriers leads to the observation of a wide variety of phenomena that, in their turn, can give an interesting insight on the fundamental properties of the structures under examination. In the present thesis, we will start analyzing zero-dimensional systems, focusing on how electrons localized onto an island can take part in the transport through the whole system; by precisely tuning the tunnel coupling strength between this island and its surroundings, we will then show how it is possible to move from a zero- to a one-dimensional system. Afterwards, the inverse path will be studied: a one-dimensional system is electrically characterized, proving itself to split up due to disorder into several zero-dimensional structures. (orig.)

Electric Vehicle Grid Integration | Transportation Research | NREL

Science.gov (United States)

Electric Vehicle Grid Integration Electric Vehicle Grid Integration Illustration of a house with a in the garage, is connected via a power cord to a household outlet. A sustainable transportation sustainable transportation technologies to increase the capacity, efficiency, and stability of the grid

Changes in electrical transport and density of states of phase change materials upon resistance drift

International Nuclear Information System (INIS)

Krebs, Daniel; Bachmann, Tobias; Jonnalagadda, Prasad; Dellmann, Laurent; Raoux, Simone

2014-01-01

Phase-change memory technology has become more mature in recent years. But some fundamental problems linked to the electrical transport properties in the amorphous phase of phase-change materials still need to be solved. The increase of resistance over time, called resistance drift, for example, poses a major challenge for the implementation of multilevel storage, which will eventually be necessary to remain competitive in terms of high storage densities. To link structural properties with electrical transport, a broader knowledge of (i) changes in the density of states (DoS) upon structural relaxation and (ii) the influence of defects on electrical transport is required. In this paper, we present temperature-dependent conductivity and photo-conductivity measurements on the archetype phase change material GeTe. It is shown that trap-limited band transport at high temperatures (above 165 K) and variable range hopping at low temperatures are the predominating transport mechanism. Based on measurements of the temperature dependence of the optical band gap, modulated photo-conductivity and photo-thermal deflection spectroscopy, a DoS model for GeTe was proposed. Using this DoS, the temperature dependence of conductivity and photo-conductivity has been simulated. Our work shows how changes in the DoS (band gap and defect distributions) will affect the electrical transport before and after temperature-accelerated drift. The decrease in conductivity upon annealing can be explained entirely by an increase of the band gap by about 12%. However, low-temperature photo-conductivity measurements revealed that a change in the defect density may also play a role

Bentonite electrical conductivity: a model based on series–parallel transport

KAUST Repository

Lima, Ana T.

2010-01-30

Bentonite has significant applications nowadays, among them as landfill liners, in concrete industry as a repairing material, and as drilling mud in oil well construction. The application of an electric field to such perimeters is under wide discussion, and subject of many studies. However, to understand the behaviour of such an expansive and plastic material under the influence of an electric field, the perception of its electrical properties is essential. This work serves to compare existing data of such electrical behaviour with new laboratorial results. Electrical conductivity is a pertinent parameter since it indicates how much a material is prone to conduct electricity. In the current study, total conductivity of a compacted porous medium was established to be dependent upon density of the bentonite plug. Therefore, surface conductivity was addressed and a series-parallel transport model used to quantify/predict the total conductivity of the system. © The Author(s) 2010.

Electrical railway transportation systems

CERN Document Server

Brenna, Morris; Zaninelli, Dario

2018-01-01

Allows the reader to deepen their understanding of various technologies for both fixed power supply installations of railway systems and for railway rolling stock. This book explores the electric railway systems that play a crucial role in the mitigation of congestion and pollution caused by road traffic. It is divided into two parts: the first covering fixed power supply systems, and the second concerning the systems for railway rolling stock. In particular, after a historical introduction to the framework of technological solutions in current use, the authors investigate electrification systems for the power supply of rail vehicles, trams, and subways. Electrical Railway Transportation Systems explores the direct current systems used throughout the world for urban and suburban transport, which are also used in various countries for regional transport. It provides a study of alternating current systems, whether for power supply frequency or for special railway frequency, that are used around the world for ...

Strong dopant dependence of electric transport in ion-gated MoS2

NARCIS (Netherlands)

Piatti, Erik; Chen, Qihong; Ye, Jianting

2017-01-01

We report modifications of the temperature-dependent transport properties of MoS2 thin flakes via field-driven ion intercalation in an electric double layer transistor. We find that intercalation with Li+ ions induces the onset of an inhomogeneous superconducting state. Intercalation with K+ leads

Probing electrical transport in individual carbon nanotubes and junctions

International Nuclear Information System (INIS)

Kim, Tae-Hwan; Wendelken, John F; Li Anping; Du Gaohui; Li Wenzhi

2008-01-01

The electrical transport properties of individual carbon nanotubes (CNTs) and multi-terminal junctions of CNTs are investigated with a quadraprobe scanning tunneling microscope. The CNTs used in this study are made of stacked herringbone-type conical graphite sheets with a cone angle of ∼20 deg. to the tube axis, and the CNT junctions have no catalytic particles in the junction areas. The CNTs have a significantly higher resistivity than conventional CNTs with concentric walls. The straight CNTs display linear current-voltage (I-V) characteristics, indicating diffusive transport rather than ballistic transport. The structural deformation in CNTs with bends substantially increases the resistivity in comparison with that for the straight segments on the same CNTs, and the I-V curve departs slightly from linearity in curved segments. The junction area of the CNT junctions behaves like an ohmic-type scattering center with linear I-V characteristics. In addition, a gating effect has not been observed, in contrast to the case for conventional multi-walled CNT junctions. These unusual transport properties can be attributed to the enhanced inter-layer interaction in the herringbone-type CNTs.

Fabrication and Transport Properties of Manganite-Polyacrylamide-Based Composites

Directory of Open Access Journals (Sweden)

Viorel Sandu

2009-01-01

Full Text Available We present the fabrication and transport properties of a series of composites made of La2/3Sr1/3MnO3 and acrylamide-based copolymers. The most important result is the very narrow transition, of only 27 K, displayed by the peak that appears around the metal-insulator transition of the composites made with poly(acrylamide-vinylacetate. Although the amount of polymer is rather low, different copolymers change drastically the electric transport characteristics.

Computing and the electrical transport properties of coupled quantum networks

Science.gov (United States)

Cain, Casey Andrew

In this dissertation a number of investigations were conducted on ballistic quantum networks in the mesoscopic range. In this regime, the wave nature of electron transport under the influence of transverse magnetic fields leads to interesting applications for digital logic and computing circuits. The work specifically looks at characterizing a few main areas that would be of interest to experimentalists who are working in nanostructure devices, and is organized as a series of papers. The first paper analyzes scaling relations and normal mode charge distributions for such circuits in both isolated and open (terminals attached) form. The second paper compares the flux-qubit nature of quantum networks to the well-established spintronics theory. The results found exactly contradict the conventional school of thought for what is required for quantum computation. The third paper investigates the requirements and limitations of extending the Thevenin theorem in classic electric circuits to ballistic quantum transport. The fourth paper outlines the optimal functionally complete set of quantum circuits that can completely satisfy all sixteen Boolean logic operations for two variables.

Modification of electrical properties of polymer membranes by ion implantation

International Nuclear Information System (INIS)

Dworecki, K.; Hasegawa, T.; Sudlitz, K.; Wasik, S.

2000-01-01

This paper presents an experimental study of the electrical properties of polymer ion irradiated polyethylene terephthalate (PET) membranes. The polymer samples have been implanted with a variety of ions (O 5+ , N 4+ , Kr 9+ ) by the energy of 10 keV/q up to doses of 10 15 ions/cm 2 and then they were polarized in an electric field of 4.16x10 6 V/m at non-isothermal conditions. The electrical properties and the changes in the chemical structure of implanted membrane were measured by conductivity and discharge currents and FTIR spectra. Electrical conductivity of the membranes PET increases to 1-3 orders of magnitude after implantation and is determined by the charge transport caused by free space charge and by thermal detrapping of charge carriers. The spectra of thermally induced discharge current (TDC) shows that ion irradiated PET membranes are characterized by high ability to accumulate charge

Magnetothermoelectric transport properties in phosphorene

Science.gov (United States)

Ma, R.; Liu, S. W.; Deng, M. X.; Sheng, L.; Xing, D. Y.; Sheng, D. N.

2018-02-01

We numerically study the electrical and thermoelectric transport properties in phosphorene in the presence of both a magnetic field and disorder. The quantized Hall conductivity is similar to that of a conventional two-dimensional electron gas, but the positions of all the Hall plateaus shift to the left due to the spectral asymmetry, in agreement with the experimental observations. The thermoelectric conductivity and Nernst signal exhibit remarkable anisotropy, and the thermopower is nearly isotropic. When a bias voltage is applied between top and bottom layers of phosphorene, both thermopower and Nernst signal are enhanced and their peak values become large.

Electrical and thermoelectric transport properties of two-dimensional fermionic systems with k-cubic spin-orbit coupling.

Science.gov (United States)

Mawrie, Alestin; Verma, Sonu; Ghosh, Tarun Kanti

2017-09-01

We investigate effect of k-cubic spin-orbit interaction on electrical and thermoelectric transport properties of two-dimensional fermionic systems. We obtain exact analytical expressions of the inverse relaxation time (IRT) and the Drude conductivity for long-range Coulomb and short-range delta scattering potentials. The IRT reveals that the scattering is completely suppressed along the three directions θ = (2n+1)π/3 with n=1,2,3. We also obtain analytical results of the thermopower and thermal conductivity at low temperature. The thermoelectric transport coefficients obey the Wiedemann-Franz law, even in the presence of k-cubic Rashba spin-orbit interaction (RSOI) at low temperature. In the presence of quantizing magnetic field, the signature of the RSOI is revealed through the appearance of the beating pattern in the Shubnikov-de Haas (SdH) oscillations of thermopower and thermal conductivity in low magnetic field regime. The empirical formulae for the SdH oscillation frequencies accurately describe the locations of the beating nodes. The beating pattern in magnetothermoelectric measurement can be used to extract the spin-orbit coupling constant. © 2017 IOP Publishing Ltd.

Electrical and thermoelectric transport properties of two-dimensional fermionic systems with k-cubic spin-orbit coupling

Science.gov (United States)

Mawrie, Alestin; Verma, Sonu; Kanti Ghosh, Tarun

2017-11-01

We investigate the effect of k-cubic spin-orbit interaction on the electrical and thermoelectric transport properties of two-dimensional fermionic systems. We obtain exact analytical expressions of the inverse relaxation time (IRT) and the Drude conductivity for long-range Coulomb and short-range delta scattering potentials. The IRT reveals that the scattering is completely suppressed along the three directions θ^\\prime = (2n+1)π/3 with n=1, 2, 3 . We also obtain analytical results of the thermopower and thermal conductivity at low temperature. The thermoelectric transport coefficients obey the Wiedemann-Franz law, even in the presence of k-cubic Rashba spin-orbit interaction (RSOI) at low temperature. In the presence of a quantizing magnetic field, the signature of the RSOI is revealed through the appearance of the beating pattern in the Shubnikov-de Haas (SdH) oscillations of thermopower and thermal conductivity in the low magnetic field regime. The empirical formulae for the SdH oscillation frequencies accurately describe the locations of the beating nodes. The beating pattern in magnetothermoelectric measurement can be used to extract the spin-orbit coupling constant.

Acousto-electric transport in MgO/ZnO-covered graphene on SiC

Science.gov (United States)

Liou, Y.-T.; Hernández-Mínguez, A.; Herfort, J.; Lopes, J. M. J.; Tahraoui, A.; Santos, P. V.

2017-11-01

We investigate the acousto-electric transport induced by surface acoustic waves (SAWs) in epitaxial graphene (EG) coated by a MgO/ZnO film. The deposition of a thin MgO layer protects the EG during the sputtering of a piezoelectric ZnO film for the efficient generation of SAWs. We demonstrate by Raman and electric measurements that the coating does not harm the EG structural and electronic properties. We report the generation of two SAW modes with frequencies around 2 GHz. For both modes, we measure acousto-electric currents in EG devices placed in the SAW propagation path. The currents increase linearly with the SAW power, reaching values up to almost two orders of magnitude higher than in previous reports for acousto-electric transport in EG on SiC. Our results agree with the predictions from the classical relaxation model of the interaction between SAWs and a two dimensional electron gas.

Nanostructured ZnO films: A study of molecular influence on transport properties by impedance spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Sappia, Luciano D.; Trujillo, Matias R. [Instituto Superior de Investigaciones Biológicas (INSIBIO), CONICET, Chacabuco 461, T4000ILI San Miguel de Tucumán (Argentina); Laboratorio de Medios e Interfases (LAMEIN), Departamento de Bioingeniería, Fac. de Cs. Exactas y Tecnología, Universidad Nacional de Tucumán, Av. Independencia 1800, 4000 San Miguel de Tucumán (Argentina); Lorite, Israel [Division of Superconductivity and Magnetism, Institute for Experimental Physics II, University of Leipzig, Linnéstrasse 5, 04103 Leipzig (Germany); Madrid, Rossana E., E-mail: rmadrid@herrera.unt.edu.ar [Instituto Superior de Investigaciones Biológicas (INSIBIO), CONICET, Chacabuco 461, T4000ILI San Miguel de Tucumán (Argentina); Laboratorio de Medios e Interfases (LAMEIN), Departamento de Bioingeniería, Fac. de Cs. Exactas y Tecnología, Universidad Nacional de Tucumán, Av. Independencia 1800, 4000 San Miguel de Tucumán (Argentina); Tirado, Monica [NanoProject and Laboratorio de Nanomateriales y Propiedades Dieléctricas, Departamento de Física, Universidad Nacional de Tucumán, Avenida Independencia 1800, Tucumán (Argentina); Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) (Argentina); and others

2015-10-15

Graphical abstract: - Highlights: • We study electrical transport in nanostructured ZnO films by impedance spectroscopy. • Bioaggregates on the surface produce strong changes in film transport properties. • This behavior is explained by modeling data with RC parallel circuits. • Electrical responses of ZnO films to aggregates are promising for biosensing. - Abstract: Nanomaterials based on ZnO have been used to build glucose sensors due to its high isoelectric point, which is important when a protein like Glucose Oxidase (GOx) is attached to a surface. It also creates a biologically friendly environment to preserve the activity of the enzyme. In this work we study the electrical transport properties of ZnO thin films (TFs) and single crystals (SC) in contact with different solutions by using impedance spectroscopy. We have found that the composition of the liquid, by means of the charge of the ions, produces strong changes in the transport properties of the TF. The enzyme GOx and phosphate buffer solutions have the major effect in the conduction through the films, which can be explained by the entrapment of carriers at the grain boundaries of the TFs. These results can help to design a new concept in glucose biosensing.

The influence of hydrogen on the chemical, mechanical, optical/electronic, and electrical transport properties of amorphous hydrogenated boron carbide

International Nuclear Information System (INIS)

Nordell, Bradley J.; Karki, Sudarshan; Nguyen, Thuong D.; Rulis, Paul; Caruso, A. N.; Paquette, Michelle M.; Purohit, Sudhaunshu S.; Li, Han; King, Sean W.; Dutta, Dhanadeep; Gidley, David; Lanford, William A.

2015-01-01

Because of its high electrical resistivity, low dielectric constant (κ), high thermal neutron capture cross section, and robust chemical, thermal, and mechanical properties, amorphous hydrogenated boron carbide (a-B x C:H y ) has garnered interest as a material for low-κ dielectric and solid-state neutron detection applications. Herein, we investigate the relationships between chemical structure (atomic concentration B, C, H, and O), physical/mechanical properties (density, porosity, hardness, and Young's modulus), electronic structure [band gap, Urbach energy (E U ), and Tauc parameter (B 1/2 )], optical/dielectric properties (frequency-dependent dielectric constant), and electrical transport properties (resistivity and leakage current) through the analysis of a large series of a-B x C:H y thin films grown by plasma-enhanced chemical vapor deposition from ortho-carborane. The resulting films exhibit a wide range of properties including H concentration from 10% to 45%, density from 0.9 to 2.3 g/cm 3 , Young's modulus from 10 to 340 GPa, band gap from 1.7 to 3.8 eV, Urbach energy from 0.1 to 0.7 eV, dielectric constant from 3.1 to 7.6, and electrical resistivity from 10 10 to 10 15 Ω cm. Hydrogen concentration is found to correlate directly with thin-film density, and both are used to map and explain the other material properties. Hardness and Young's modulus exhibit a direct power law relationship with density above ∼1.3 g/cm 3 (or below ∼35% H), below which they plateau, providing evidence for a rigidity percolation threshold. An increase in band gap and decrease in dielectric constant with increasing H concentration are explained by a decrease in network connectivity as well as mass/electron density. An increase in disorder, as measured by the parameters E U and B 1/2 , with increasing H concentration is explained by the release of strain in the network and associated decrease in structural disorder. All of these correlations in a

Electron Transport Properties of Ge nanowires

Science.gov (United States)

Hanrath, Tobias; Khondaker, Saiful I.; Yao, Zhen; Korgel, Brian A.

2003-03-01

Electron Transport Properties of Ge nanowires Tobias Hanrath*, Saiful I. Khondaker, Zhen Yao, Brian A. Korgel* *Dept. of Chemical Engineering, Dept. of Physics, Texas Materials Institute, and Center for Nano- and Molecular Science and Technology University of Texas at Austin, Austin, Texas 78712-1062 e-mail: korgel@mail.che.utexas.edu Germanium (Ge) nanowires with diameters ranging from 6 to 50 nm and several micrometer in length were grown via a supercritical fluid-liquid-solid synthesis. Parallel electron energy loss spectroscopy (PEELS) was employed to study the band structure and electron density in the Ge nanowires. The observed increase in plasmon peak energy and peak width with decreasing nanowire diameter is attributed to quantum confinement effects. For electrical characterization, Ge nanowires were deposited onto a patterned Si/SiO2 substrate. E-beam lithography was then used to form electrode contacts to individual nanowires. The influence of nanowire diameter, surface chemistry and crystallographic defects on electron transport properties were investigated and the comparison of Ge nanowire conductivity with respect to bulk, intrinsic Ge will be presented.

Electrical transport properties of an isolated CdS microrope composed of twisted nanowires

Science.gov (United States)

Yu, Gui-Feng; Yu, Miao; Pan, Wei; Han, Wen-Peng; Yan, Xu; Zhang, Jun-Cheng; Zhang, Hong-Di; Long, Yun-Ze

2015-01-01

CdS is one of the important II-VI group semiconductors. In this paper, the electrical transport behavior of an individual CdS microrope composed of twisted nanowires is studied. It is found that the current-voltage ( I- V) characteristics show two distinct power law regions from 360 down to 60 K. Space-charge-limited current (SCLC) theory is used to explain these temperature- and electric-field-dependent I-V curves. The I-V data can be well fitted by this theory above 100 K, and the corresponding carrier mobility, trap energy, and trap concentration are also obtained. However, the I-V data exhibit some features of the Coulomb blockade effect below 80 K.

Electrical transport properties of an isolated CdS microrope composed of twisted nanowires.

Science.gov (United States)

Yu, Gui-Feng; Yu, Miao; Pan, Wei; Han, Wen-Peng; Yan, Xu; Zhang, Jun-Cheng; Zhang, Hong-Di; Long, Yun-Ze

2015-01-01

CdS is one of the important II-VI group semiconductors. In this paper, the electrical transport behavior of an individual CdS microrope composed of twisted nanowires is studied. It is found that the current-voltage (I-V) characteristics show two distinct power law regions from 360 down to 60 K. Space-charge-limited current (SCLC) theory is used to explain these temperature- and electric-field-dependent I-V curves. The I-V data can be well fitted by this theory above 100 K, and the corresponding carrier mobility, trap energy, and trap concentration are also obtained. However, the I-V data exhibit some features of the Coulomb blockade effect below 80 K.

Ab Initio Calculations of Transport Properties of Vanadium Oxides

Science.gov (United States)

Lamsal, Chiranjivi; Ravindra, N. M.

2018-04-01

The temperature-dependent transport properties of vanadium oxides have been studied near the Fermi energy using the Kohn-Sham band structure approach combined with Boltzmann transport equations. V2O5 exhibits significant thermoelectric properties, which can be attributed to its layered structure and stability. Highly anisotropic electrical conduction in V2O5 is clearly manifested in the calculations. Due to specific details of the band structure and anisotropic electron-phonon interactions, maxima and crossovers are also seen in the temperature-dependent Seebeck coefficient of V2O5. During the phase transition of VO2, the Seebeck coefficient changes by 18.9 µV/K, which is close to (within 10% of) the observed discontinuity of 17.3 µV/K.

Electrical Transport and Magnetoresistance in Single-Wall Carbon Nanotubes Films

Directory of Open Access Journals (Sweden)

Vitaly KSENEVICH

2014-06-01

Full Text Available Electrical transport properties and magnetoresistance of single-wall carbon nanotubes (SWCNT films were investigated within temperature range (2 – 300 K and in magnetic fields up to 8 T. A crossover between metallic (dR/dT > 0 and non-metallic (dR/dT < 0 temperature dependence of the resistance as well as low-temperature saturation of the resistance in high bias regime indicated on the diminishing of role of the contact barriers between individual nanotubes essential for the charge transport in SWCNT arrays. The magnetoresistance (MR data demonstrated influence of weak localization and electron-electron interactions on charge transport properties in SWCNT films. The low-field negative MR with positive upturn was observed at low temperatures. At T > 10 K only negative MR was observed in the whole range of available magnetic fields. The negative MR can be approximated using 1D weak localization (WL model. The low temperature positive MR is induced by contribution from electron-electron interactions. DOI: http://dx.doi.org/10.5755/j01.ms.20.2.6311

Electricity for road transport, flexible power systems and wind power

Energy Technology Data Exchange (ETDEWEB)

Nielsen, Lars Henrik; Ravn, H.; Meibom, P. (and others)

2011-12-15

The aim of the project is to analyse the potential synergistic interplay that may arise between the power sector and the transport sector, if parts of the road transport energy needs are based on electricity via the utilisation of plug-in hybrid electric vehicles and pure electric vehicles. The project focuses on the technical elements in the chain that comprises: 1: The electric vehicle status, potentials and expected development. Electric batteries are in focus in this part of the analysis. 2: Analysis of plug-in hybrid electric vehicle interacting with a local grid. 3: Analysis of grid-vehicle connection systems including technical regulation options and analysis of needs for standardisation. 4: Setting up scenarios covering potential developments for utilizing electric drive trains in road transport. Period: Up to year 2030. 5: Analysis of capacity constraints in the electricity grid (transmission and distribution) as consequence of increasing electricity demand, and new flexible consumption patterns from segments in the transport sector, and as consequence of increasing capacity on wind power in the system. 6: Setting up and analysis of combined scenarios covering both the heat and power system and the transport sector. (Author)

Electronic transport properties

International Nuclear Information System (INIS)

Young, W.H.

1985-01-01

The theory of the electron transport properties of liquid alkali metals is described. Conductivity coefficients, Boltzmann theory, Ziman theory, alkali form factors, Ziman theory and alkalis, Faber-Ziman alloy theory, Faber-Ziman theory and alkali-alkali methods, status of Ziman theory, and other transport properties, are all discussed. (UK)

Modification of electrical properties of polymer membranes by ion implantation (II)

International Nuclear Information System (INIS)

Dworecki, K.; Hasegawa, T.; Sudlitz, K.; Slezak, A.; Wasik, S.

2001-01-01

In the present work we report on the results of an experimental study of the electrical properties of polymer ion irradiated polyethylene terephthalate (PET) membranes. The polymer samples have been implanted under vacuum at room temperature with a variety of ions (C 4+ , O 6+ , S 7+ ) at energy of 10 keV/q up to the dose of 10 15 ions/cm 2 and then they were polarized in an electric field of 4.16x10 6 V/m at non-isothermal conditions. The electrical properties and changes in chemical structure of ion implanted membranes were studied by the conductivity and discharge currents measurements, FTIR spectra and differential thermal analysis. The electrical conductivity of the PET membranes is determined by the charge transport caused by free space charge and by thermal releasing of charge carriers. The spectra of thermally induced discharge current (TDC) shows that ion irradiated PET membranes are characterized by high ability of charge accumulation

Electrical transport properties in Fe-Cr nanocluster-assembled granular films

Science.gov (United States)

Wang, Xiong-Zhi; Wang, Lai-Sen; Zhang, Qin-Fu; Liu, Xiang; Xie, Jia; Su, A.-Mei; Zheng, Hong-Fei; Peng, Dong-Liang

2017-09-01

The Fe100-xCrx nanocluster-assembled granular films with Cr atomic fraction (x) ranging from 0 to 100 were fabricated by using a plasma-gas-condensation cluster deposition system. The TEM characterization revealed that the uniform Fe clusters were coated with a Cr layer to form a Fe-Cr core-shell structure. Then, the as-prepared Fe100-xCrx nanoclusters were randomly assembled into a granular film in vacuum environments with increasing the deposition time. Because of the competition between interfacial resistance and shunting effect of Cr layer, the room temperature resistivity of the Fe100-xCrx nanocluster-assembled granular films first increased and then decreased with increasing the Cr atomic fraction (x), and revealed a maximum of 2 × 104 μΩ cm at x = 26 at.%. The temperature-dependent longitudinal resistivity (ρxx), magnetoresistance (MR) effect and anomalous Hall effect (AHE) of these Fe100-xCrx nanocluster-assembled granular films were also studied systematically. As the x increased from 0 to 100, the ρxx of all samples firstly decreased and then increased with increasing the measuring temperature. The dependence of ρxx on temperature could be well addressed by a mechanism incorporated for the fluctuation-induced-tunneling (FIT) conduction process and temperature-dependent scattering effect. It was found that the anomalous Hall effect (AHE) had no legible scaling relation in Fe100-xCrx nanocluster-assembled granular films. However, after deducting the contribution of tunneling effect, the scaling relation was unambiguous. Additionally, the Fe100-xCrx nanocluster-assembled granular films revealed a small negative magnetoresistance (MR), which decreased with the increase of x. The detailed physical mechanism of the electrical transport properties in these Fe100-xCrx nanocluster-assembled granular films was also studied.

Electric-field effects on electronic tunneling transport in magnetic barrier structures

International Nuclear Information System (INIS)

Guo Yong; Wang Hao; Gu Binglin; Kawazoe, Yoshiyuki

2000-01-01

Electronic transport properties in magnetic barrier structures under the influence of an electric field have been investigated. The results indicate that the characteristics of transmission resonance are determined not only by the structure and the incident wave vector but also strongly by the electric field. It is shown that the transmission coefficient at resonance in the low-energy range is suppressed by applying the electric field for electron tunneling through the magnetic barrier structure, arranged with identical magnetic barriers and wells. It is also shown that the transmission resonance is first enhanced up to optimal resonance, and then suppressed with further increased electric field for electron tunneling through the magnetic barrier structure, arranged with unidentical building blocks. Strong suppression of the current density is also found in the magnetic barrier structure, arranged with two different building blocks

Electrical Properties of Sunflower Achenes

Directory of Open Access Journals (Sweden)

Novák Ján

2014-12-01

Full Text Available This work contains the results of measuring the electrical properties of sunflower achenes. The interest in electrical properties of biological materials resulted in engineering research in this field. The results of measurements are used for determining the moisture content, the surface level of liquid and grainy materials, for controlling the presence of pests in grain storage, for the quantitative determination of mechanical damage, in the application of dielectric heating, and in many other areas. Electrical measurements of these materials are of fundamental importance in relation to the analysis of quantity of absorbed water and dielectric heating characteristics. It is a well-known fact that electrical properties of materials, namely dielectric constant and conductivity, are affected by the moisture content of material. This fact is important for the design of many commercial moisturetesting instruments for agricultural products. The knowledge of dielectric properties of materials is necessary for the application of dielectric heating. The aim of this work was to measure conductivity, dielectric constant and loss tangent on samples of sunflower achenes, the electrical properties of which had not been sufficiently measured. Measurements were performed under variable moisture content and the frequency of electric field ranging from 1 MHz to 16 MHz, using a Q meter with coaxial probe. It was concluded that conductivity, dielectric constant and loss tangent increased with increasing moisture content, and dielectric constant and loss tangent decreased as the frequency of electric field increased.

Atomic transport properties

International Nuclear Information System (INIS)

Freyss, M.

2015-01-01

As presented in the first chapter of this book, atomic transport properties govern a large panel of nuclear fuel properties, from its microstructure after fabrication to its behaviour under irradiation: grain growth, oxidation, fission product release, gas bubble nucleation. The modelling of the atomic transport properties is therefore the key to understanding and predicting the material behaviour under irradiation or in storage conditions. In particular, it is noteworthy that many modelling techniques within the so-called multi-scale modelling scheme of materials make use of atomic transport data as input parameters: activation energies of diffusion, diffusion coefficients, diffusion mechanisms, all of which are then required to be known accurately. Modelling approaches that are readily used or which could be used to determine atomic transport properties of nuclear materials are reviewed here. They comprise, on the one hand, static atomistic calculations, in which the migration mechanism is fixed and the corresponding migration energy barrier is calculated, and, on the other hand, molecular dynamics calculations and kinetic Monte-Carlo simulations, for which the time evolution of the system is explicitly calculated. (author)

Electric-field effects in optically generated spin transport

International Nuclear Information System (INIS)

Miah, M. Idrish

2009-01-01

Transport of spin-polarized electrons in semiconductors is studied experimentally. Spins are generated by optical excitation because of the selection rules governing optical transitions from heavy-hole and light-hole states to conduction-band states. Experiments designed for the control of spins in semiconductors investigate the bias-dependent spin transport process and detect the spin-polarized electrons during transport. A strong bias dependence is observed. The electric-field effects on the spin-polarized electron transport are also found to be depended on the excitation photon energy and temperature. Based on a field-dependent spin relaxation mechanism, the electric-field effects in the transport process are discussed.

Electric-field effects in optically generated spin transport

Energy Technology Data Exchange (ETDEWEB)

Miah, M. Idrish [Nanoscale Science and Technology Centre and School of Biomolecular and Physical Sciences, Griffith University, Nathan, Brisbane, QLD 4111 (Australia); Department of Physics, University of Chittagong, Chittagong 4331 (Bangladesh)], E-mail: m.miah@griffith.edu.au

2009-05-25

Transport of spin-polarized electrons in semiconductors is studied experimentally. Spins are generated by optical excitation because of the selection rules governing optical transitions from heavy-hole and light-hole states to conduction-band states. Experiments designed for the control of spins in semiconductors investigate the bias-dependent spin transport process and detect the spin-polarized electrons during transport. A strong bias dependence is observed. The electric-field effects on the spin-polarized electron transport are also found to be depended on the excitation photon energy and temperature. Based on a field-dependent spin relaxation mechanism, the electric-field effects in the transport process are discussed.

Current Transport Properties of Monolayer Graphene/n-Si Schottky Diodes

Science.gov (United States)

Pathak, C. S.; Garg, Manjari; Singh, J. P.; Singh, R.

2018-05-01

The present work reports on the fabrication and the detailed macroscopic and nanoscale electrical characteristics of monolayer graphene/n-Si Schottky diodes. The temperature dependent electrical transport properties of monolayer graphene/n-Si Schottky diodes were investigated. Nanoscale electrical characterizations were carried out using Kelvin probe force microscopy and conducting atomic force microscopy. Most the values of ideality factor and barrier height are found to be in the range of 2.0–4.4 and 0.50–0.70 eV for monolayer graphene/n-Si nanoscale Schottky contacts. The tunneling of electrons is found to be responsible for the high value of ideality factor for nanoscale Schottky contacts.

An Electricity-Alcohol Transportation Strategy

Energy Technology Data Exchange (ETDEWEB)

Morris, David [Inst. for Local Self-Reliance, Minneapolis (United States)

2006-07-15

In the United States, a dual fuel system may be emerging as a consensus strategy for a rapid transition to an oil free transportation system. The energy source for the vehicles will be a combination of electricity and alcohols. The technology will be a plug-in hybrid electric vehicle whose batteries can be charged from the national grid system, and a backup flexible fueled engine, primarily fueled by alcohols.

Transport properties in GaTe under hydrostatic pressure

International Nuclear Information System (INIS)

Gouskov, L.; Carvalho, M.

1980-01-01

First results of the resistivity rho(perpendicular) and rho(parallel)(perpendicular and parallel to the normal to the cleavage plane) under hydrostatic pressure (1 bar <= P <= 3 kbar) on GaTe grown by the Bridgman method, are given and discussed. The analysis of electrical transport properties of GaTe under pressure, indicates a complex nature of the acceptor level in this material. The activation energy Esub(a) has a negative pressure coefficient which is sample dependent. The comparison of the variations of rho(parallel) and rho(perpendicular) versus pressure shows that the activation energy E of the rho(parallel)/rho(perpendicular) ratio has also a negative pressure coefficient which can be justified in the frame of a one-dimensional disorder model proposed by Maschke and Schmid, in order to explain the transport properties in the direction of the normal to the cleavage plane. (author)

Study of transport properties of bodies with a perovskite structure: application to the MgSiO3 perovskite

International Nuclear Information System (INIS)

Kapusta, Benedicte

1990-01-01

After some recalls on transport in ionic solids (Nernst-Einstein relationship, variation of ionic conductivity, hybrid conduction, fast ionic conduction), this research thesis presents the physical properties of perovskites and more particularly the structure and stability of the MgSiO 3 perovskite: structure and elastic properties, electric conductivity and transport properties in compounds with a perovskite structure. Then, the author reports the experimental study of the KZnF 3 perovskite (a structural analogous of MgSiO 3 ): measurements of electric conductivity under pressure, measurements under atmospheric pressure, result discussion. The next part addresses the numerical simulation of MgSiO 3 : simulation techniques (generalities on molecular dynamics, model description), investigation of structural, elastic and thermodynamic properties, diffusion properties in quadratic phase [fr

Electrical Transport and Magnetoresistance Properties of Tensile-Strained CaMnO3 Thin Films

Science.gov (United States)

Ullery, Dustin; Lawson, Bridget; Zimmerman, William; Neubauer, Samuel; Chaudhry, Adeel; Hart, Cacie; Yong, Grace; Smolyaninova, Vera; Kolagani, Rajeswari

We will present our studies of the electrical transport and magnetoresistance properties of tensile strained CaMnO3 thin films. We observe that the resistivity decreases significantly as the film thickness decreases which is opposite to what is observed in thin films of hole doped manganites. The decrease in resistivity is more pronounced in the films on (100) SrTiO3, with resistivity of the thinnest films being about 3 orders of magnitude lower than that of bulk CaMnO3. Structural changes accompanying resistivity changes cannot be fully explained as due to tensile strain, and indicate the presence of oxygen vacancies. These results also suggest a coupling between tensile strain and oxygen deficiency, consistent with predictions from models based on density functional theory calculations. We observe a change in resistance under the application of moderate magnetic field. Experiments are underway to understand the origin of the magnetoresistance and its possible relation to the tensile strain effects. We acknowledge support from: Towson Office of University Undergraduate Research, Fisher Endowment Grant and Undergraduate Research Grants from the Fisher College of Science and Mathematics, and Seed Funding Grant from the School of Emerging technologies.

Interactions between Radial Electric Field, Transport and Structure in Helical Plasmas

International Nuclear Information System (INIS)

Ida, Katsumi and others

2006-01-01

Control of the radial electric field is considered to be important in helical plasmas, because the radial electric field and its shear are expected to reduce neoclassical and anomalous transport, respectively. Particle and heat transport, that determines the radial structure of density and electron profiles, sensitive to the structure of radial electric field. On the other hand, the radial electric field itself is determined by the plasma parameters. In general, the sign of the radial electric field is determined by the plasma collisionality, while the magnitude of the radial electric field is determined by the temperature and/or density gradients. Therefore the structure of radial electric field and temperature and density are strongly coupled through the particle and heat transport and formation mechanism of radial electric field. Interactions between radial electric field, transport and structure in helical plasmas is discussed based on the experiments on Large Helical Device

Magnetoelectric and transport properties of (GaMn)Sb thin films: A ferrimagnetic phase in dilute alloys

Energy Technology Data Exchange (ETDEWEB)

Calderón, Jorge A. [Universidad Nacional de Colombia – Bogotá, Dpto. de Física, Grupo de Materiales Nanoestructurados y sus Aplicaciones, Cra. 30 No. 45-03 Edificio 404 Lab. 121C Ciudad Universitaria, Bogotá (Colombia); Mesa, F., E-mail: fredy.mesa@urosario.edu.co [Grupo NanoTech, Facultad de Ciencias Naturales y Matemáticas, Universidad del Rosario, Cra. 24 No. 63C-69, Bogotá (Colombia); Dussan, A. [Universidad Nacional de Colombia – Bogotá, Dpto. de Física, Grupo de Materiales Nanoestructurados y sus Aplicaciones, Cra. 30 No. 45-03 Edificio 404 Lab. 121C Ciudad Universitaria, Bogotá (Colombia)

2017-02-28

Highlights: • (GaMn)Sb thin films were fabricated using the direct current (DC) magnetron co-sputtering. • Presence of ferrimagnetic (Mn{sub 2}Sb) and ferromagnetic (Mn{sub 2}Sb{sub 2}) phases. • A minor difference of 1% was found with respect to percolation theory, which confirmed the validity of the diffusional model in semiconductor alloys with magnetic properties. • Increase in the localized states density (N{sub F}) with increasing substrate temperature. - Abstract: We studied the electrical, magnetic, and transport properties of (GaMn)Sb thin films fabricated by the direct current magnetron co-sputtering method. Using X-ray powder diffraction measurements, we identified the presence of ferrimagnetic (Mn{sub 2}Sb) and ferromagnetic (Mn{sub 2}Sb{sub 2}) phases within the films. We also measured the magnetization of the films versus an applied magnetic field as well as their hysteresis curves at room temperature. We determined the electrical and transport properties of the films through temperature-dependent resistivity measurements using the Van Der Pauw method. The main contribution to the transport process was variable range hopping. Hopping parameters were calculated using percolation theory and refined using the diffusional model. In addition, we determined that all samples had p type semiconductor behavior, that there was an increase in the density of localized states near the Fermi level, and that the binary magnetic phases influenced the electrical properties and transport mechanisms.

Electrical transport and magnetic properties of misfit layered compounds intercalated with cobaltocene

NARCIS (Netherlands)

Morales, J; Santos, J; Baas, J; Wiegers, GA; Martinez, JL

1999-01-01

The electrical and magnetic properties of misfit layered cobaltocene complexes of composition (PbS)(1.18)(TiS2)(2)(CoCp2)(0.28), (PbS)(1.14)(TaS2)(2)(CoCp2)(0.28), and (PbSe)(1.12)(NbSe2)(2)(CoCp2)(0.27) [Cp = C5H5-] were investigated. All the pristine chalcogenides studied exhibit a metallic

Transport properties of dense matter

International Nuclear Information System (INIS)

Itoh, Naoki; Mitake, Shinichi; Iyetomi, Hiroshi; Ichimaru, Setsuo

1983-01-01

Transport coefficients, electrical and thermal conductivities in particular, are essential physical quantities for the theories of stellar structure. Since the discoveries of pulsars and X-ray stars, an accurate evaluation of the transport coefficients in the dense matter has become indispensable to the quantitative understanding of the observed neutron stars. The authors present improved calculations of the electrical and thermal conductivities of the dense matter in the liquid metal phase, appropriate to white dwarfs and neutron stars. (Auth.)

An international perspective on electric transportation. Survey on electric road transport 2012

Energy Technology Data Exchange (ETDEWEB)

Weeda, M; Kroon, P [ECN Policy Studies, Petten (Netherlands); Appels, D [Agentschap NL, Utrecht (Netherlands)

2012-09-15

To compare the Dutch governmental efforts and developments in the field of electric road transport, the Ministry of Economic Affairs, Agriculture and Innovation has asked ECN Policy Studies and NL Agency to conduct an international assessment on electric mobility. The countries that have been considered are: Austria, Belgium, Denmark, France, Germany, the Netherlands, Norway, Portugal, Spain, UK, China, USA and South Korea. The Netherlands has a high ambition level with regard to the number of electric vehicles and is one of the leaders as for the envisaged number of charging points. In the field of R and D, Germany, South Korea and China take the lead, followed by France, the UK, the USA and Austria. However, the assessment has only looked at specific funds for electric mobility, and has not looked at general R and D and innovation funds. The Netherlands has several electro-mobility field tests, but is not leading in number. Norway and Austria are leading countries when it comes to implementation of public charging infrastructure.

Transport properties in a monolayer graphene modulated by the realistic magnetic field and the Schottky metal stripe

Science.gov (United States)

Lu, Jian-Duo; Li, Yun-Bao; Liu, Hong-Yu; Peng, Shun-Jin; Zhao, Fei-Xiang

2016-09-01

Based on the transfer-matrix method, a systematic investigation of electron transport properties is done in a monolayer graphene modulated by the realistic magnetic field and the Schottky metal stripe. The strong dependence of the electron transmission and the conductance on the incident angle of carriers is clearly seen. The height, position as well as width of the barrier also play an important role on the electron transport properties. These interesting results are very useful for understanding the tunneling mechanism in the monolayer graphene and helpful for designing the graphene-based electrical device modulated by the realistic magnetic field and the electrical barrier.

Tunable electronic transport properties of silicon-fullerene-linked nanowires: Semiconductor, conducting wire, and tunnel diode

OpenAIRE

Nishio, Kengo; Ozaki, Taisuke; Morishita, Tetsuya; Mikami, Masuhiro

2010-01-01

We explore the possibility of controllable tuning of the electronic transport properties of silicon-fullerene-linked nanowires by encapsulating guest atoms into their cages. Our first-principles calculations demonstrate that the guest-free nanowires are semiconductors, and do not conduct electricity. The iodine or sodium doping improves the transport properties, and makes the nanowires metallic. In the junctions of I-doped and Na-doped NWs, the current travels through the boundary by quantum ...

City electric transport preferences and motives of the Russian students

Science.gov (United States)

Romanova, Elena

2017-10-01

The share of electric transport in Russia is very small. Many cities refuse operation of urban electric passenger transportation. Basic reasons of it are high cost value and expensive operation. In Moscow the emphasis is placed on development of rail electric transport. It provides fast movement and pollutes the city environment less. The Moscow students understand that for an urban transportation ecological compatibility and safety are important but they choose buses and individual cars with the internal combustion engine for daily use. The main criteria of the choice are the speed and comfort. Ecological compatibility of the individual transport costs on one of the last places.

Formulation of confinement matrices and characterization of their transport properties from solid to melt state

International Nuclear Information System (INIS)

Grandjean, A.

2006-07-01

The author gives an overview of his research activity during which she worked on three main subjects. The first one dealt with the investigation of transport mechanisms in metal alloys (experimental investigation of diffusion in amorphous alloys, oxidation mechanism of Zircaloy-4 under temperature and in water or in dry oxygen). The second one dealt with the synthesis and properties of specific confinement matrices (effect of chemical composition on sintering of a carbonate powder, effect of microstructure of high Mo and P content vitro-crystals on lixiviation properties, incorporation of fluorine compounds in the case of borosilicate systems). The third one dealt with the transport in borosilicate glasses and melts (ionic transport, properties, and electrical transport glass-RuO 2 particles composites)

Electrical and magneto transport properties of

Indian Academy of Sciences (India)

samples. The morphology of crystal grains shows that the grains are nearly uniform in size and spherical. Electrical .... 1.5406 Å) in angular steps of 0.02 .... table to scattering by impurities, defects, grain boundaries .... because of different orientations of opposite spins, an energy ... 2000 Colossal magneto resistance oxides.

Thermal transport properties of niobium and some niobium base alloys from 80 to 16000K

International Nuclear Information System (INIS)

Moore, J.P.; Graves, R.S.; Williams, R.K.

1980-01-01

The electrical resistivities and absolute Seebeck coefficients of 99.8 at. % niobium with a RRR of 36, Nb-4.8 at. % W, Nb-5 at. % Mo, Nb-10 at. % Mo, and Nb-2.4 at. % Mo-2.4 at. % Zr were measured from 80 to 1600 0 K, and the thermal conductivities of the niobium and Nb-5 at. % W were measured from 80 to 1300 0 K. A technique is described for measuring the electrical resistivity and Seebeck coefficient of a specimen during radial heat flow measurements of the thermal conductivity. The transport property results, which had uncertainties of +-0.4%for electrical resistivity and +-1.4% for thermal conductivity, showed the influence of tungsten and molybdenum solutes on the transport properties of niobium and were used to obtain the electronic Lorenz function of pure niobium, which was found to approach the Sommerfeld value at high temperatures

Electrical properties of a new sulfur-containing polymer for optoelectronic application

Science.gov (United States)

ElAkemi, ElMehdi; Jaballah, Nejmeddine; Ouada, Hafedh Ben; Majdoub, Mustapha

2015-06-01

An original polythiophene derivative was characterized to develop the optoelectronic properties of sulfur-containing π-conjugated polymer. The optical properties of the polymer were investigated by UV-visible absorption spectroscopy and atomic force microscopy. Investigations of the electrical characteristics of polymer diodes are reported. We present current-voltage characteristics and impedance spectroscopy measurements performed on partially sulfur-containing thin films in sandwich structure ITO/sulfur-containing polymer/Al. The conduction mechanisms in these layers are identified to be a space-charge-limited current. The AC electrical transport of the sulfur-containing polymer is studied as a function of frequency (100 Hz-10 MHz) and temperature in impedance spectroscopy analyses. We interpreted Cole-Cole plots in terms of the equivalent circuit model as a single parallel resistance and a capacitance network in series with a relatively small resistance. The evolution of the electrical parameters deduced from fitting of the experimental data is discussed.

Study of Electrical Transport Properties of Thin Films Used as HTL and as Active Layer in Organic Solar Cells, through Impedance Spectroscopy Measurements

Directory of Open Access Journals (Sweden)

Camilo A. Otalora

2016-01-01

Full Text Available Impedance spectroscopy (IS is used for studying the electrical transport properties of thin films used in organic solar cells with structure ITO/HTL/active layer/cathode, where PEDOT:PSS (poly(3,4-ethylenedioxythiophene:polystyrene sulfonic acid and CuPC (tetrasulfonated copper-phthalocyanine were investigated as HTL (hole transport layer and P3HT:PCBM (poly-3-hexylthiophene:phenyl-C61-butyric acid methyl ester blends prepared from mesitylene and chlorobenzene based solutions were studied as active layer and Ag and Al were used as cathode. The study allowed determining the influence of the type of solvent used for the preparation of the active layer as well as the speed at which the solvents are removed on the carriers mobility. The effect of exposing the layer of P3HT to the air on its mobility was also studied. It was established that samples of P3HT and P3HT:PCBM prepared using mesitylene as a solvent have mobility values significantly higher than those prepared from chlorobenzene which is the solvent most frequently used. It was also determined that the mobility of carriers in P3HT films strongly decreases when this sample is exposed to air. In addition, it was found that the electrical properties of P3HT:PCBM thin films can be improved by removing the solvent slowly which is achieved by increasing the pressure inside the system of spin-coating during the film growth.

Transport Properties of the Nuclear Pasta Phase with Quantum Molecular Dynamics

Science.gov (United States)

Nandi, Rana; Schramm, Stefan

2018-01-01

We study the transport properties of nuclear pasta for a wide range of density, temperature, and proton fractions, relevant for different astrophysical scenarios adopting a quantum molecular dynamics model. In particular, we estimate the values of shear viscosity as well as electrical and thermal conductivities by calculating the static structure factor S(q) using simulation data. In the density and temperature range where the pasta phase appears, the static structure factor shows irregular behavior. The presence of a slab phase greatly enhances the peak in S(q). However, the effect of irregularities in S(q) on the transport coefficients is not very dramatic. The values of all three transport coefficients are found to have the same orders of magnitude as found in theoretical calculations for the inner crust matter of neutron stars without the pasta phase; therefore, the values are in contrast to earlier speculations that a pasta layer might be highly resistive, both thermally and electrically.

Electrical Power Systems for NASA's Space Transportation Program

Science.gov (United States)

Lollar, Louis F.; Maus, Louis C.

1998-01-01

Marshall Space Flight Center (MSFC) is the National Aeronautics and Space Administration's (NASA) lead center for space transportation systems development. These systems include earth to orbit launch vehicles, as well as vehicles for orbital transfer and deep space missions. The tasks for these systems include research, technology maturation, design, development, and integration of space transportation and propulsion systems. One of the key elements in any transportation system is the electrical power system (EPS). Every transportation system has to have some form of electrical power and the EPS for each of these systems tends to be as varied and unique as the missions they are supporting. The Preliminary Design Office (PD) at MSFC is tasked to perform feasibility analyses and preliminary design studies for new projects, particularly in the space transportation systems area. All major subsystems, including electrical power, are included in each of these studies. Three example systems being evaluated in PD at this time are the Liquid Fly Back Booster (LFBB) system, the Human Mission to Mars (HMM) study, and a tether based flight experiment called the Propulsive Small Expendable Deployer System (ProSEDS). These three systems are in various stages of definition in the study phase.

Morphology dependent electrical transport behavior in gold nanostructures

International Nuclear Information System (INIS)

Alkhatib, A.; Souier, T.; Chiesa, M.

2011-01-01

The mechanism of electron transport in ultra-thin gold films is investigated and its dependence on the gold islands size is reported. For gold films of thickness below 38 nm, the electrical transport occurs by tunneling within electrically discontinuous islands of gold. Simmons model for metal-insulator-metal junction describes the non-ohmic experimental current-voltage curves obtained by means of conductive atomic force microscopy. Field emission is the predominant transport for thicknesses below 23 nm while direct tunneling occurs in thicker films. The transition between the two regimes is controlled by the gold islands size and their inter-distance.

Electric field and transport in W7-AS

International Nuclear Information System (INIS)

Kick, M.; Maassberg, H.; Anton, M.; Baldzuhn, J.; Endler, M.; Goerner, C.; Hirsch, M.; Weller, A.; Zoletnik, S.

1999-01-01

At W7-AS, confinement properties are analysed and compared mainly with neoclassical predictions for quite different conditions. Low-density electron cyclotron resonance heating (ECRH) discharges allow access to the very-long-mean-free-path regime for electrons (T e up to 6 keV) whereas pure neutral beam injections (NBI) and combined NBI/ECRH discharges at high density (T i approx. T e ≥ 1 keV at n e approx. 10 20 m -3 ) lead to high performance (τ B up to 50 ms). Depending on the achieved temperatures, the experimental transport analysis in the plasma core is consistent with the neoclassical predictions. The experimentally observed 'electron root' feature with strong E r >0 is driven by the convective flux of ripple-trapped suprathermal electrons generated by the ECRH absorption. 'Optimum' confinement is obtained in discharges with narrow density, but broad temperature profiles with steep gradients in the region of low densities and strong E r <0 close to the plasma edge. The large radial electric fields, both positive and negative, strongly reduce neoclassical transport. The achieved temperatures, however, are limited by the strong temperature dependence of the neoclassical transport. (author)

Theoretical prediction of the electronic transport properties of the Al-Cu alloys based on the first-principle calculation and Boltzmann transport equation

Science.gov (United States)

Choi, Garam; Lee, Won Bo

Metal alloys, especially Al-based, are commonly-used materials for various industrial applications. In this paper, the Al-Cu alloys with varying the Al-Cu ratio were investigated based on the first-principle calculation using density functional theory. And the electronic transport properties of the Al-Cu alloys were carried out using Boltzmann transport theory. From the results, the transport properties decrease with Cu-containing ratio at the temperature from moderate to high, but with non-linearity. It is inferred by various scattering effects from the calculation results with relaxation time approximation. For the Al-Cu alloy system, where it is hard to find the reliable experimental data for various alloys, it supports understanding and expectation for the thermal electrical properties from the theoretical prediction. Theoretical and computational soft matters laboratory.

Electric Properties Measurement of Lentil

Directory of Open Access Journals (Sweden)

Novák Ján

2018-03-01

Full Text Available This paper contains the results of the electric properties measurement of lentil set. Electric measurements with use of these materials are of fundamental importance in relation to the analysis of quantity of absorbed water and dielectric heating characteristics. The aim of this paper was to perform the measurements of conductivity, dielectric constant and loss tangent on samples of lentil, the electrical properties of which had not been sufficiently measured. Measurements were performed under various moisture contents, and the frequency of electric field ranged from 1 MHz to 16 MHz, using a Q meter with coaxial probe. It was concluded that conductivity, relative permittivity and loss tangent increased with an increase in moisture content, and dielectric constant and loss tangent decreased as the frequency of electric field increased.

Electricity for Road Transport, Flexible Power Systems and Wind Power

DEFF Research Database (Denmark)

Nielsen, Lars Henrik; Ravn, Hans; Meibom, Peter

The aim of the project is to analyse the potential synergistic interplay that may arise between the power sector and the transport sector, if parts of the road transport energy needs are based on electricity via the utilisation of plug-in hybrid electric vehicles and pure electric vehicles....... The project focuses on the technical elements in the chain that comprises: 1: The electric vehicle status, potentials and expected development. Electric batteries are in focus in this part of the analysis. 2: Analysis of plug-in hybrid electric vehicle interacting with a local grid. 3: Analysis of grid-vehicle...

Thermodynamic and transport properties of two-temperature SF6 plasmas

International Nuclear Information System (INIS)

Wang Weizong; Rong Mingzhe; Wu Yi; Spencer, Joseph W.; Yan, Joseph D.; Mei, DanHua

2012-01-01

This paper deals with thermodynamic and transport properties of SF 6 plasmas in a two-temperature model for both thermal equilibrium and non-equilibrium conditions. The species composition and thermodynamic properties are numerically determined using the two-temperature Saha equation and Guldberg-Waage equation according to deviation of van de Sanden et al. Transport properties including diffusion coefficient, viscosity, thermal conductivity, and electrical conductivity are calculated with most recent collision interaction potentials by adopting Devoto’s electron and heavy particle decoupling approach but expanded to the third-order approximation (second-order for viscosity) in the frame of Chapman–Enskog method. The results are computed for various values of pressures from 0.1 atm to 10 atm and ratios of the electron temperature to the heavy particle temperature from 1 to 20 with electron temperature range from 300 to 40 000 K. In the local thermodynamic equilibrium regime, results are compared with available results of previously published studies.

Electron transport properties in ZnO nanowires/poly(3-hexylthiophene) hybrid nanostructure

International Nuclear Information System (INIS)

Cheng Ke; Cheng Gang; Wang Shujie; Fu Dongwei; Zou Bingsuo; Du Zuliang

2010-01-01

The ZnO nanowires (NWs) array/poly(3-hexylthiophene) (P3HT) hybrid prototype device was fabricated. An ultraviolet (UV) light of λ = 350 nm is used to investigate the photo-electric properties of the ZnO NWs array and hybrid structure. In this way, we can avoid the excitation of P3HT, which can give us a real electron transport ability of ZnO NWs itself. Our results demonstrated a higher and faster photo-electric response of 3 s for the hybrid structure while 9 s for the ZnO NWs array. The surface states related slow photo-electric response was also observed for them. The charge transfer mechanism and the influence of surface states were discussed. The current work provides us profound understandings on the electron transport ability of ZnO NWs array in a working hybrid polymer solar cell, which is crucial for optimizing the device performance.

Electrical transport properties of nanoplates shaped tungsten oxide embedded poly(vinyl-alcohol) film

Science.gov (United States)

Das, Amit Kumar; Chatterjee, Piyali; Meikap, Ajit Kumar

2018-04-01

Tungsten oxide (WO3) nanoplates have been synthesized via hydrothermal method. The average crystallite size of the nanoplates is 28.9 ± 0.5 nm. The direct and indirect band gap of WO3 is observed. The AC conductivity of PVA-WO3 composite film has been observed and carrier transport mechanism follows correlated barrier hopping model. The maximum barrier height of the composite film is 0.1 eV. The electric modulus reflects the non-Debye type behaviour of relaxation time which is simulated by Kohlrausch-Willims-Watts (KWW) function.

Kinetic parameters, collision rates, energy exchanges and transport coefficients of non-thermal electrons in premixed flames at sub-breakdown electric field strengths

KAUST Repository

Bisetti, Fabrizio; El Morsli, Mbark

2014-01-01

The effects of an electric field on the collision rates, energy exchanges and transport properties of electrons in premixed flames are investigated via solutions to the Boltzmann kinetic equation. The case of high electric field strength, which

Electrical energy conversion and transport an interactive computer-based approach

CERN Document Server

Karady, George G

2013-01-01

Provides relevant material for engineering students and practicing engineers who want to learn the basics of electrical power transmission, generation, and usage This Second Edition of Electrical Energy Conversion and Transport is thoroughly updated to address the recent environmental effects of electric power generation and transmission, which have become more important in conjunction with the deregulation of the industry. The maintenance and development of the electrical energy generation and transport industry requires well-trained engineers who are able to use mode

Visualizing Carrier Transport in Metal Halide Perovskite Nanoplates via Electric Field Modulated Photoluminescence Imaging.

Science.gov (United States)

Hu, Xuelu; Wang, Xiao; Fan, Peng; Li, Yunyun; Zhang, Xuehong; Liu, Qingbo; Zheng, Weihao; Xu, Gengzhao; Wang, Xiaoxia; Zhu, Xiaoli; Pan, Anlian

2018-05-09

Metal halide perovskite nanostructures have recently been the focus of intense research due to their exceptional optoelectronic properties and potential applications in integrated photonics devices. Charge transport in perovskite nanostructure is a crucial process that defines efficiency of optoelectronic devices but still requires a deep understanding. Herein, we report the study of the charge transport, particularly the drift of minority carrier in both all-inorganic CsPbBr 3 and organic-inorganic hybrid CH 3 NH 3 PbBr 3 perovskite nanoplates by electric field modulated photoluminescence (PL) imaging. Bias voltage dependent elongated PL emission patterns were observed due to the carrier drift at external electric fields. By fitting the drift length as a function of electric field, we obtained the carrier mobility of about 28 cm 2 V -1 S -1 in the CsPbBr 3 perovskite nanoplate. The result is consistent with the spatially resolved PL dynamics measurement, confirming the feasibility of the method. Furthermore, the electric field modulated PL imaging is successfully applied to the study of temperature-dependent carrier mobility in CsPbBr 3 nanoplates. This work not only offers insights for the mobile carrier in metal halide perovskite nanostructures, which is essential for optimizing device design and performance prediction, but also provides a novel and simple method to investigate charge transport in many other optoelectronic materials.

Hydration effect on the electronic transport properties of oligomeric phenylene ethynylene molecular junctions

International Nuclear Information System (INIS)

Zong-Liang, Li; Huai-Zhi, Li; Yong, Ma; Guang-Ping, Zhang; Chuan-Kui, Wang

2010-01-01

A first-principles computational method based on the hybrid density functional theory is developed to simulate the electronic transport properties of oligomeric phenylene ethynylene molecular junctions with H 2 O molecules accumulated in the vicinity as recently reported by Na et al. [Nanotechnology 18 424001 (2007)]. The numerical results show that the hydrogen bonds between the oxygen atoms of the oligomeric phenylene ethynylene molecule and H 2 O molecules result in the localisation of the molecular orbitals and lead to the lower transition peaks. The H 2 O molecular chains accumulated in the vicinity of the molecular junction can not only change the electronic structure of the molecular junctions, but also open additional electronic transport pathways. The obvious influence of H 2 O molecules on the electronic structure of the molecular junction and its electronic transport properties is thus demonstrated. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

Effect of oxygen content on the electrical transport and superconducting properties of Pb0.5Sr2.5Y0.6Ca0.4Cu2O7-y

International Nuclear Information System (INIS)

Ruan, K.Q.; China Univ. of Science and Technology, Hefei, AH; Jin, H.; China Univ. of Science and Technology, Hefei, AH; Feng, Y.; China Univ. of Science and Technology, Hefei, AH; Zhou, Y.Q.; China Univ. of Science and Technology, Hefei, AH; Chui, X.D.; China Univ. of Science and Technology, Hefei, AH; Wang, C.Y.; China Univ. of Science and Technology, Hefei, AH; Cao, L.Z.; China Univ. of Science and Technology, Hefei, AH; Wang, L.B.; Zhang, Y.H.

1997-01-01

Two kinds of methods have been used to synthesize Pb 0.5 Sr 2.5 Y 0.6 Ca 0.4 Cu 2 O 7-y samples. The synthesized sample using the first method shows superconductivity, while that using the second method exhibits a localized behavior at low temperatures Thermogravimetric analysis (TGA) and electrical transport measurements have been carried out on superconducting and nonsuperconducting samples grown under the two kinds of synthesis conditions and the effect of oxygen content on the transport and superconducting properties is discussed briefly. (orig.)

Electrical transport of SiNWs array after covalent attachment of new organic functionalities

Directory of Open Access Journals (Sweden)

Marianna Ambrico

2012-05-01

Full Text Available Modification of the electrical transport of a random network of silicon nanowires assembled on n‐ silicon support, after silicon nanowires functionalization by chlorination/alkylation procedure , is here described and discussed. We show that the organic functionalities induce charge transfer at single SiNW and produce doping‐like effect that is kept in the random network too. The\tSiNWs\tnetwork\talso\tpresents\ta\tsurface recombination velocity lower than that of bulk silicon. Interestingly, the functionalized silicon nanowires/n‐Si junctions display photo‐yield and open circuit voltages higher than those including oxidized silicon nanowire networks. Electrical properties stability in time of junctions embedding propenyl terminated silicon nanowires network and transport modification after secondary functionalization is also shown. These results suggest a possible route for the integration of functionalized\tSi\tnanowires,\talthough\trandomly distributed, in stable large area photovoltaic or molecule sensitive based devices.

Elastic and transport properties in polycrystals of crackedgrains: Cross-property relations and microstructure

Energy Technology Data Exchange (ETDEWEB)

Berryman, J.G.

2007-10-02

Some arguments of Bristow (1960) concerning the effects of cracks on elastic and transport (i.e., electrical or thermal conduction) properties of cold-worked metals are reexamined. The discussion is posed in terms of a modern understanding of bounds and estimates for physical properties of polycrystals--in contrast to Bristow's approach using simple mixture theory. One type of specialized result emphasized here is the cross-property estimates and bounds that can be obtained using the methods presented. Our results ultimately agree with those of Bristow, i.e., confirming that microcracking is not likely to be the main cause of the observed elastic behavior of cold-worked metals. However, it also becomes clear that the mixture theory approach to the analysis is too simple and that crack-crack interactions are necessary for proper quantitative study of Bristow's problem.

Neoclassical transport and radial electric fields in TJ-K

International Nuclear Information System (INIS)

Rahbarnia, K.; Greiner, F.; Ramisch, M.; Stroth, U.; Greiner, F.

2003-01-01

The neoclassical transport is investigated in the torsatron TJ-K, which is operated with a low-temperature plasma. In the low-collisionality regime neoclassical losses are not intrinsically ambipolar, leading to the formation of a radial electric field which acts on both neoclassical and turbulent transport. This electric field is measured with a combination of Langmuir and emissive probes. The data are compared with the ambipolar electric field calculated with an analytic model. The experimental fields are positive and larger than the calculated ones. Direct losses of the fast electrons might explain this discrepancy. (orig.)

Electronic structure and transport properties of quasi-one-dimensional carbon nanomaterials

Directory of Open Access Journals (Sweden)

Y. N. Wu

2017-09-01

Full Text Available Based on the density functional theory combined with the nonequilibrium Green’s function, the influence of the wrinkle on the electronic structures and transport properties of quasi-one-dimensional carbon nanomaterials have been investigated, in which the wrinkled armchair graphene nanoribbons (wAGNRs and the composite of AGNRs and single walled carbon nanotubes (SWCNTs were considered with different connection of ripples. The wrinkle adjusts the electronic structures and transport properties of AGNRs. With the change of the strain, the wAGNRs for three width families reveal different electrical behavior. The band gap of AGNR(6 increases in the presence of the wrinkle, which is opposite to that of AGNR(5 and AGNR(7. The transport of AGNRs with the widths 6 or 7 has been modified by the wrinkle, especially by the number of isolated ripples, but it is insensitive to the strain. The nanojunctions constructed by AGNRs and SWCNTs can form the quantum wells, and some specific states are confined in wAGNRs. Although these nanojunctions exhibit the metallic, they have poor conductance due to the wrinkle. The filling of C20 into SWCNT has less influence on the electronic structure and transport of the junctions. The width and connection type of ripples have greatly influenced on the electronic structures and transport properties of quasi-one-dimensional nanomaterials.

Electronic structure and transport properties of quasi-one-dimensional carbon nanomaterials

Science.gov (United States)

Wu, Y. N.; Cheng, P.; Wu, M. J.; Zhu, H.; Xiang, Q.; Ni, J.

2017-09-01

Based on the density functional theory combined with the nonequilibrium Green's function, the influence of the wrinkle on the electronic structures and transport properties of quasi-one-dimensional carbon nanomaterials have been investigated, in which the wrinkled armchair graphene nanoribbons (wAGNRs) and the composite of AGNRs and single walled carbon nanotubes (SWCNTs) were considered with different connection of ripples. The wrinkle adjusts the electronic structures and transport properties of AGNRs. With the change of the strain, the wAGNRs for three width families reveal different electrical behavior. The band gap of AGNR(6) increases in the presence of the wrinkle, which is opposite to that of AGNR(5) and AGNR(7). The transport of AGNRs with the widths 6 or 7 has been modified by the wrinkle, especially by the number of isolated ripples, but it is insensitive to the strain. The nanojunctions constructed by AGNRs and SWCNTs can form the quantum wells, and some specific states are confined in wAGNRs. Although these nanojunctions exhibit the metallic, they have poor conductance due to the wrinkle. The filling of C20 into SWCNT has less influence on the electronic structure and transport of the junctions. The width and connection type of ripples have greatly influenced on the electronic structures and transport properties of quasi-one-dimensional nanomaterials.

Electronic transport properties of phenylacetylene molecular junctions

International Nuclear Information System (INIS)

Liu Wen; Cheng Jie; Yan Cui-Xia; Li Hai-Hong; Wang Yong-Juan; Liu De-Sheng

2011-01-01

Electronic transport properties of a kind of phenylacetylene compound— (4-mercaptophenyl)-phenylacetylene are calculated by the first-principles method in the framework of density functional theory and the nonequilibrium Green's function formalism. The molecular junction shows an obvious rectifying behaviour at a bias voltage larger than 1.0 V. The rectification effect is attributed to the asymmetry of the interface contacts. Moreover, at a bias voltage larger than 2.0 V, which is not referred to in a relevant experiment [Fang L, Park J Y, Ma H, Jen A K Y and Salmeron M 2007 Langmuir 23 11522], we find a negative differential resistance phenomenon. The negative differential resistance effect may originate from the change of the delocalization degree of the molecular orbitals induced by the bias. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

Electrokinetic transport of aerobic microorganisms under low-strength electric fields.

Science.gov (United States)

Maillacheruvu, Krishnanand Y; Chinchoud, Preethi R

2011-01-01

To investigate the feasibility of utilizing low strength electric fields to transport commonly available mixed cultures such as those from an activated sludge process, bench scale batch reactor studies were conducted in sand and sandy loam soils. A readily biodegradable substrate, dextrose, was used to test the activity of the transported microorganisms. Electric field strengths of 7V, 10.5V, and 14V were used. Results from this investigation showed that an electric field strength of 0.46 Volts per cm was sufficient to transport activated sludge microorganisms across a sandy loam soil across a distance of about 8 cm in 72 h. More importantly, the electrokinetically transported microbial culture remained active and viable after the transport process and was biodegrade 44% of the dextrose in the soil medium. Electrokinetic treatment without microorganisms resulted in removal of 37% and the absence of any treatment yielded a removal of about 15%.

Low-temperature electrical transport in B-doped ultrananocrystalline diamond film

International Nuclear Information System (INIS)

Li, Lin; Zhao, Jing; Hu, Zhaosheng; Quan, Baogang; Li, Junjie; Gu, Changzhi

2014-01-01

B-doped ultrananocrystalline diamond (UNCD) films are grown using hot-filament chemical vapor deposition method, and their electrical transport properties varying with temperature are investigated. When the B-doped concentration of UNCD film is low, a step-like increase feature of the resistance is observed with decreasing temperature, reflecting at least three temperature-modified electronic state densities at the Fermi level according to three-dimensional Mott's variable range hopping transport mechanism, which is very different from that of reported B-doped nanodiamond. With increasing B-doped concentration, a superconductive transformation occurs in the UNCD film and the highest transformation temperature of 5.3 K is observed, which is higher than that reported for superconducting nanodiamond films. In addition, the superconducting coherence length is about 0.63 nm, which breaks a reported theoretical and experimental prediction about ultra-nanoscale diamond's superconductivity

Role of inter-tube coupling and quantum interference on electrical transport in carbon nanotube junctions

Science.gov (United States)

Tripathy, Srijeet; Bhattacharyya, Tarun Kanti

2016-09-01

Due to excellent transport properties, Carbon nanotubes (CNTs) show a lot of promise in sensor and interconnect technology. However, recent studies indicate that the conductance in CNT/CNT junctions are strongly affected by the morphology and orientation between the tubes. For proper utilization of such junctions in the development of CNT based technology, it is essential to study the electronic properties of such junctions. This work presents a theoretical study of the electrical transport properties of metallic Carbon nanotube homo-junctions. The study focuses on discerning the role of inter-tube interactions, quantum interference and scattering on the transport properties on junctions between identical tubes. The electronic structure and transport calculations are conducted with an Extended Hückel Theory-Non Equilibrium Green's Function based model. The calculations indicate conductance to be varying with a changing crossing angle, with maximum conductance corresponding to lattice registry, i.e. parallel configuration between the two tubes. Further calculations for such parallel configurations indicate onset of short and long range oscillations in conductance with respect to changing overlap length. These oscillations are attributed to inter-tube coupling effects owing to changing π orbital overlap, carrier scattering and quantum interference of the incident, transmitted and reflected waves at the inter-tube junction.

Beyond sustainable transport. Electric car features and services

Energy Technology Data Exchange (ETDEWEB)

Malinen, P.; Pirhonen, V.; Giesecke, R. [Aalto Univ. School of Science, Espoo (Finland). BIT Research Centre

2011-07-01

The overall aim of the Finnish SIMBe project (www.SIMBe.fi) is to significantly accelerate the introduction of sustainable electric mobility in Finland. SIMBe stands for Smart Infrastructures for Electric Mobility in Built Environments. The fundamental assumption of the project is that electric (e-) mobility is inherently more sustainable than mobility based on fossil fuels. However, as has been widely recognized in the e-mobility field, the currently used batteries are expensive, often more expensive than the rest of the particular electric vehicle (EV) that they propel. There are two opposite schools of thought how to address this problem, which can be summarized as follows: a) Leave the battery in peace, as it is precious. Use it only to propel the EV of which it is an integral part. Use it instead of fuel, and do not use it for any other applications. The EV's sole purpose is that of a transportation device. b) Make as much use of the battery as possible, as it is precious. Involve vehicle to grid (V2G) or vehicle to house charging. Additionally, invent new features, meanings and services for the battery driven EV, which go distinctively beyond transport. The SIMBe project decided to opt for school (b), based on the smart energy production and distribution scenario, in which electric and hybrid vehicles' batteries will deliver energy on demand to the grid. SIMBe aims to prepare key Finnish industrial players and consumers for the transition to this new energy-transportation paradigm. But how can we replace the conservative understanding of the 'transport only' school by a holistic view of what features, meanings and services are actually possible by using a large scale fleet of 'batteries on wheels'? The Nordic Climate Festival (at) Aalto provided the unique opportunity to tap into the knowledge and creativity of students within the Nordic countries. Being properly prepared and facilitated, a workshop may provide some insights and

Beyond sustainable transport. Electric car features and services

Energy Technology Data Exchange (ETDEWEB)

Malinen, P; Pirhonen, V; Giesecke, R [Aalto Univ. School of Science, Espoo (Finland). BIT Research Centre

2011-07-01

The overall aim of the Finnish SIMBe project (www.SIMBe.fi) is to significantly accelerate the introduction of sustainable electric mobility in Finland. SIMBe stands for Smart Infrastructures for Electric Mobility in Built Environments. The fundamental assumption of the project is that electric (e-) mobility is inherently more sustainable than mobility based on fossil fuels. However, as has been widely recognized in the e-mobility field, the currently used batteries are expensive, often more expensive than the rest of the particular electric vehicle (EV) that they propel. There are two opposite schools of thought how to address this problem, which can be summarized as follows: a) Leave the battery in peace, as it is precious. Use it only to propel the EV of which it is an integral part. Use it instead of fuel, and do not use it for any other applications. The EV's sole purpose is that of a transportation device. b) Make as much use of the battery as possible, as it is precious. Involve vehicle to grid (V2G) or vehicle to house charging. Additionally, invent new features, meanings and services for the battery driven EV, which go distinctively beyond transport. The SIMBe project decided to opt for school (b), based on the smart energy production and distribution scenario, in which electric and hybrid vehicles' batteries will deliver energy on demand to the grid. SIMBe aims to prepare key Finnish industrial players and consumers for the transition to this new energy-transportation paradigm. But how can we replace the conservative understanding of the 'transport only' school by a holistic view of what features, meanings and services are actually possible by using a large scale fleet of 'batteries on wheels'? The Nordic Climate Festival (at) Aalto provided the unique opportunity to tap into the knowledge and creativity of students within the Nordic countries. Being properly prepared and facilitated, a workshop may provide some insights and ideas. In scope of the

Surface electrical properties of stainless steel fibres: An AFM-based study

International Nuclear Information System (INIS)

Yin, Jun; D’Haese, Cécile; Nysten, Bernard

2015-01-01

Highlights: • Surface electrical conductivity of stainless steel fibre is measured and mapped by CS-AFM. • Surface potential of stainless steel fibre is measured and mapped by KPFM. • Surface electronic properties are governed by the chromium oxide passivation layer. • Electron tunnelling through the passivation layer is the dominant mechanisms for conduction. - Abstract: Atomic force microscopy (AFM) electrical modes were used to study the surface electrical properties of stainless steel fibres. The surface electrical conductivity was studied by current sensing AFM and I–V spectroscopy. Kelvin probe force microscopy was used to measure the surface contact potential. The oxide film, known as passivation layer, covering the fibre surface gives rise to the observation of an apparently semiconducting behaviour. The passivation layer generally exhibits a p-type semiconducting behaviour, which is attributed to the predominant formation of chromium oxide on the surface of the stainless steel fibres. At the nanoscale, different behaviours are observed from points to points, which may be attributed to local variations of the chemical composition and/or thickness of the passivation layer. I–V curves are well fitted with an electron tunnelling model, indicating that electron tunnelling may be the predominant mechanism for electron transport

Electrical properties and conduction mechanisms of Ru-based thick-film (cermet) resistors

International Nuclear Information System (INIS)

Pike, G.E.; Seager, C.H.

1977-01-01

This paper presents an experimental study of the electrical conduction mechanisms in thick-film (cermet) resistor. The resistors were made from one custom and three commercially formulated inks with sheet resistivities ranging from 10 2 to 10 6 Ω/D 7 Alembertian in decade increments. Their microstructure and composition have been examined using optical and scanning electron microscopy, electron microprobe analysis, x-ray diffraction, and various chemical analyses. This portion of our study shows that the resistors are heterogeneous mixtures of metallic metal oxide particles (approx.4 x 10 -5 cm in diameter) and a lead silicate glass. The metal oxide particles are ruthenium containing pyrochlores, and are joined to form a continuous three-dimensional network of chain segments. The principal experimental work reported here is an extensive study of the electrical transport properties of the resistors. The temperature dependence of conductance has been measured from 1.2 to 400 K, and two features common to all resistors are found. There is a pronounced decrease in conductance at low temperatures and a shallow maximum at several hundred Kelvin. Within the same range of temperatures the reversible conductance as a function of electric field from 0 to 28 kV/cm has been studied. The resistors are non-Ohmic at all temperatures, but particularly at cryogenic temperatures for low fields. At higher fields the conductance shows a linear variation with electric field. The thick-film resistors are found to have a small dielectric constant and a (nearly) frequency-independent conductance from dc to 50 MHz. The magnetoresistance to 100 kG, the Hall mobility, and the Seebeck coefficient of most of the resistors have been measured and discovered to be quite small. Many of the electrical transport properties have also been determined for the metal oxide particles which were extracted from the fired resistors

Magnetic and Electrical Properties of Leachate

Directory of Open Access Journals (Sweden)

Kartika Kirana

2011-11-01

Full Text Available Heavy metals content as well as magnetic and electrical properties of leachate from Sarimukti, West Java were studied in an attempt to seek correlation between heavy metals content and magnetic/electrical properties. Such correlation is expected to open the way for the use of magnetic/electrical properties as proxy indicators for the concentration of heavy metals in the leachate. The number of leachate samples studied is 21; 15 were taken spatially at depth of 1 m while the remaining 6 samples were taken vertically at a particular point. Measurement results showed that the heavy metals content in the leachate has a smaller concentration, except for Fe. The correlation between magnetic susceptibility and heavy metals content was found to be not so significant. The best correlation coefficient between magnetic susceptibility with heavy metals in leachate was found in Zn. Correlation between electrical conductivity and heavy metal is also not so significant, except for Zn and Cd. The use of magnetic properties as proxy indicator for heavy metals content in leachate is plausible provided that the magnetic susceptibility exceeds certain threshold value. Correlation between magnetic susceptibility, electrical conductivity and heavy metal content would be good if each quantity has a large value.

Theoretical transport analysis of density limit with radial electric field in helical plasmas

International Nuclear Information System (INIS)

Toda, S.; Itoh, K.

2010-11-01

The confinement property in helical toroidal plasmas is clarified. The analysis is performed by use of the one-dimensional transport equations with the effect of the radiative loss and the radial profile of the electric field. The analytical results in the edge region show the steep gradient in the electron temperature, which indicates the transport barrier formation. Because of the rapid increase of the radiative loss at the low electron temperature, the anomalous heat diffusivity is reduced near the edge. Next, the efficiency of the heating power input in the presence of the radiative loss is studied. The scaling of the critical density in helical devices is also derived. (author)

Electric transport properties study of bulk BaFe{sub 12}O{sub 19} by complex impedance spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Pattanayak, R., E-mail: ranjit.p20@gmail.com [Department of Physics and Astronomy, National Institute of Technology, Rourkela, Odisha (India); Panigrahi, S. [Department of Physics and Astronomy, National Institute of Technology, Rourkela, Odisha (India); Dash, T. [CSIR-Institute of Minerals and Materials Technology, Bhubaneswar, Odisha (India); Muduli, R.; Behera, D. [Department of Physics and Astronomy, National Institute of Technology, Rourkela, Odisha (India)

2015-10-01

Polycrystalline M-type hexagonal Barium ferrite (BaFe{sub 12}O{sub 19}) was prepared by the solid state reaction method. The single phase and well grain growth of micrometer range was confirmed by XRD pattern and SEM image respectively. The presence of Fe{sup 2+} and Fe{sup 3+} states were verified by XPS study. In this report, the electric transport properties of BaFe{sub 12}O{sub 19} (BaM) was systematically investigated and analyzed in the frequency range of 100 Hz to 1 MHz and temperature range of 30–200 °C. The relaxation behaviors were examined by considering both impedance and modulus formalism, to differentiate intrinsic (grain) and extrinsic (grain boundary and electrode polarization) conduction process. The co-contribution effect of grain and grain boundary was verified which appeared as a single relaxation process in the chosen frequency and temperature range. However, the sample experienced the early (even at room temperature) arrival of surface conduction which dominates over grain boundary with increasing of temperature.

URBAN PUBLIC TRANSPORT WITH THE USE OF ELECTRIC BUSES – DEVELOPMENT TENDENCIES

Directory of Open Access Journals (Sweden)

Stanisław KRAWIEC

2016-12-01

Full Text Available The programing documents of the European Union determine the direction of transport systems development, including large cities and agglomerations. The context of these actions which aim to transform into ecologically clean and sustainable transport system is a significant reduction of greenhouse gas emissions. Assuming that public transport will significantly reduce the use of combustion-powered buses, studies on urban logistic enabling the use of electric buses for public transport are needed. The article presents the variants and scenarios for electric buses implementation in urban public transport, as well as the decision algorithm to support electric bus implementation based on technological, organisational, economic and ecological variables.

TUNABLE MAGNETIC AND ELECTRICAL PROPERTIES OF Co-DOPED ZnO FILMS BY VARYING OXYGEN PARTIAL PRESSURE

OpenAIRE

L. G. WANG; H. W. ZHANG; X. L. TANG; Y. X. LI; Z. Y. ZHONG

2011-01-01

High quality Co-doped ZnO films with good reproducibility have been prepared under different oxygen partial pressure by radio-frequency magnetron sputtering. These films were characterized using numerous characterization techniques including X-ray diffraction, electrical transport, and magnetization measurements. The effect of oxygen partial pressure on the structural, magnetic, and electrical properties of Co-doped ZnO films has been systematically studied. It was found that the structural, ...

Electricity transport regimes: their impact on cogeneration

Energy Technology Data Exchange (ETDEWEB)

Cotard, Erwan [COGEN, Europe (Belgium)

2000-12-01

In many cases the main product of cogeneration is heat and the surplus electricity is sold to the grid. However, the economics of cogeneration can be influenced by transport networks (transmission and distribution): the structure of network pricing is relatively new. In a recent note from COGEN Europe it was recommended that cogenerators who use only the local distribution system should not pay for the transmission system and that tariffs should be structured in sufficient detail for the advantages of decentralisation to be realised. The article is presented under the sub-headings of (i) why is this important? (the omission of the transmission element reduces the overall price of cogeneration); (ii) the advantages of decentralised cogeneration; (iv) the theory - the different systems (the European Directive on electricity market liberalization); (v) the options for transport fees; (vi) current regimes in some EU states (vii) the case of transborder transport; impact of each system on cogeneration; recommendations to policymakers; (viii) the Netherlands and (ix) the UK.

Development of micro-four-point probe in a scanning tunneling microscope for in situ electrical transport measurement.

Science.gov (United States)

Ge, Jian-Feng; Liu, Zhi-Long; Gao, Chun-Lei; Qian, Dong; Liu, Canhua; Jia, Jin-Feng

2015-05-01

Electrons at surface may behave differently from those in bulk of a material. Multi-functional tools are essential in comprehensive studies on a crystal surface. Here, we developed an in situ microscopic four-point probe (4PP) transport measurement system on the basis of a scanning tunneling microscope (STM). In particular, convenient replacement between STM tips and micro-4PPs enables systematic investigations of surface morphology, electronic structure, and electrical transport property of a same sample surface. Performances of the instrument are demonstrated with high-quality STM images, tunneling spectra, and low-noise electrical I-V characteristic curves of a single-layer FeSe film grown on a conductive SrTiO3 surface.

Development of micro-four-point probe in a scanning tunneling microscope for in situ electrical transport measurement

Energy Technology Data Exchange (ETDEWEB)

Ge, Jian-Feng; Liu, Zhi-Long; Gao, Chun-Lei; Qian, Dong; Liu, Canhua, E-mail: canhualiu@sjtu.edu.cn, E-mail: jfjia@sjtu.edu.cn; Jia, Jin-Feng, E-mail: canhualiu@sjtu.edu.cn, E-mail: jfjia@sjtu.edu.cn [Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), Department of Physics and Astronomy, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240 (China)

2015-05-15

Electrons at surface may behave differently from those in bulk of a material. Multi-functional tools are essential in comprehensive studies on a crystal surface. Here, we developed an in situ microscopic four-point probe (4PP) transport measurement system on the basis of a scanning tunneling microscope (STM). In particular, convenient replacement between STM tips and micro-4PPs enables systematic investigations of surface morphology, electronic structure, and electrical transport property of a same sample surface. Performances of the instrument are demonstrated with high-quality STM images, tunneling spectra, and low-noise electrical I-V characteristic curves of a single-layer FeSe film grown on a conductive SrTiO{sub 3} surface.

Transport properties of a ladder with two random dimer chains

International Nuclear Information System (INIS)

Hu Dong-Sheng; Zhu Chen-Ping; Zhang Yong-Mei

2011-01-01

We investigate the transport properties of a ladder with two random dimer (RD) chains. It is found that there are two extended states in the ladder with identical RD chains and a critical state regarded as an extended state in the ladder with pairing RD chains. Such a critical state is caused by the chiral symmetry. The ladder with identical RD chains can be decoupled into two isolated RD chains and the ladder with pairing RD chains can not. The analytic expressions of the extended states are presented for the ladder with identical RD chains. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

From Cell to Tissue Properties-Modeling Skin Electroporation With Pore and Local Transport Region Formation.

Science.gov (United States)

Dermol-Cerne, Janja; Miklavcic, Damijan

2018-02-01

Current models of tissue electroporation either describe tissue with its bulk properties or include cell level properties, but model only a few cells of simple shapes in low-volume fractions or are in two dimensions. We constructed a three-dimensional model of realistically shaped cells in realistic volume fractions. By using a 'unit cell' model, the equivalent dielectric properties of whole tissue could be calculated. We calculated the dielectric properties of electroporated skin. We modeled electroporation of single cells by pore formation on keratinocytes and on the papillary dermis which gave dielectric properties of the electroporated epidermis and papillary dermis. During skin electroporation, local transport regions are formed in the stratum corneum. We modeled local transport regions and increase in their radii or density which affected the dielectric properties of the stratum corneum. The final model of skin electroporation accurately describes measured electric current and voltage drop on the skin during electroporation with long low-voltage pulses. The model also accurately describes voltage drop on the skin during electroporation with short high-voltage pulses. However, our results indicate that during application of short high-voltage pulses additional processes may occur which increase the electric current. Our model connects the processes occurring at the level of cell membranes (pore formation), at the level of a skin layer (formation of local transport region in the stratum corneum) with the tissue (skin layers) and even level of organs (skin). Using a similar approach, electroporation of any tissue can be modeled, if the morphology of the tissue is known.

Transport, Structural and Mechanical Properties of Quaternary FeVTiAl Alloy

Science.gov (United States)

Bhat, Tahir Mohiuddin; Gupta, Dinesh C.

2016-11-01

The electronic, structural, magnetic and transport properties of FeVTiAl quaternary alloy have been investigated within the framework of density functional theory. The material is a completely spin-polarized half-metallic ferromagnet in its ground state with F-43m structure. The structural stability was further confirmed by elastic constants in the cubic phase with high Young's modulus and brittle nature. The present study predicts an energy band gap of 0.72 eV in a localized minority spin channel at equilibrium lattice parameter of 6.00 Å. The transport properties of the material are discussed based on the Seebeck coefficient, and electrical and thermal conductivity coefficients. The alloy presents large values of Seebeck coefficients, ~39 μV K-1 at room temperature (300 K), and has an excellent thermoelectric performance with ZT = ~0.8.

Ultra-violet absorption induced modifications in bulk and nanoscale electrical transport properties of Al-doped ZnO thin films

Energy Technology Data Exchange (ETDEWEB)

Kumar, Mohit; Basu, Tanmoy; Som, Tapobrata, E-mail: tsom@iopb.res.in [SUNAG Laboratory, Institute of Physics, Sachivalaya Marg, Bhubaneswar 751 005 (India)

2015-08-07

Using conductive atomic force microscopy and Kelvin probe force microscopy, we study local electrical transport properties in aluminum-doped zinc oxide (ZnO:Al or AZO) thin films. Current mapping shows a spatial variation in conductivity which corroborates well with the local mapping of donor concentration (∼10{sup 20 }cm{sup −3}). In addition, a strong enhancement in the local current at grains is observed after exposing the film to ultra-violet (UV) light which is attributed to persistent photocurrent. Further, it is shown that UV absorption gives a smooth conduction in AZO film which in turn gives rise to an improvement in the bulk photoresponsivity of an n-AZO/p-Si heterojunction diode. This finding is in contrast to the belief that UV absorption in an AZO layer leads to an optical loss for the underneath absorbing layer of a heterojunction solar cell.

Lattice dynamics and substrate-dependent transport properties of (In, Yb)-doped CoSb3 skutterudite thin films

KAUST Repository

Sarath Kumar, S. R.; Cha, Dong Kyu; Alshareef, Husam N.

2011-01-01

Lattice dynamics, low-temperature electrical transport, and high-temperature thermoelectric properties of (In, Yb)-doped CoSb3thin films on different substrates are reported. Pulsed laser deposition under optimized conditions yielded single

Electrical transport properties of manganese containing pyrochlore type semiconducting oxides using impedance analyses

International Nuclear Information System (INIS)

Sumi, S.; Prabhakar Rao, P.; Mahesh, S.K.; Koshy, Peter

2012-01-01

Graphical abstract: DC conductivity variation of CaCe 1−x Mn x SnNbO 7−δ (x = 0, 0.2, 0.4 and 0.6) with inverse of temperature. Variation of conductivity with Mn concentration at 600 °C is shown in the inset. Display Omitted Highlights: ► We have observed that the structural ordering as well as grain size increase with Mn substitution. ► Impedance analysis proved that a correlated barrier hopping type conduction mechanism is involved in the materials. ► Activation energy as well as electrical conductivity increases with increase in Mn substitution. ► Localization of electrons associated with Mn 2+ and structural ordering are the key factors for the increased activation energy with Mn substitution. ► All the materials showed good NTC thermistor properties. -- Abstract: A new series of manganese containing pyrochlore type semiconducting oxides CaCe 1−x Mn x SnNbO 7−δ (x = 0, 0.2, 0.4 and 0.6) have been synthesized to study the effect of Mn substitution on the structure, microstructure and electrical properties of these samples. X-ray diffraction and scanning electron microscopy studies revealed an increase of structural ordering and grain size respectively with increase of Mn substitution. Rietveld analysis and Raman spectroscopy were also employed to corroborate the XRD results. The bulk resistance measurements with temperature exhibit negative temperature coefficient behavior. The impedance analysis of the samples revealed a non-Debye type relaxation existed in the materials. The ac conductivity variation with temperature and frequency indicates a correlated barrier hopping type conduction mechanism in these materials. The barrier height and the intersite separation for hopping influence the electrical conductivity of these samples and are found to be a function of localization of electrons associated with the Mn 2+ ions and the unit cell volume respectively. The Mn substitution increases both electrical conductivity and activation energy

Asymmetry of neoclassical transport by dipole electric field

International Nuclear Information System (INIS)

Wang Zhongtian; Wang Long

2004-01-01

Effects of dipole electric fields on neoclassical transport are studied. Large asymmetry in transport is created. The dipole fields, which are in a negative R-direction, reduce the ion drift, increase electron drift, and change the steps of excursion due to collisions. It is found that different levels of dipole field intensities have different types of transport. For the lowest level of the dipole field, the transport returns to the neoclassical one. For the highest level of the dipole field, the transport is turned to be the turbulence transport similar to the pseudo-classical transport. Experimental data may be corresponded to a large level of the dipole field intensity. (authors)

Influence of dopant concentration on the electrical properties of the CdSe-PMMA nanocomposite

Energy Technology Data Exchange (ETDEWEB)

Kaur, Ramneek; Tripathi, S. K., E-mail: surya@pu.ac.in, E-mail: surya-tr@yahoo.com [Department of Physics, Center of Advanced Study in Physics, Panjab University, Chandigarh-160 014 (India)

2016-05-06

This paper reports the synthesis and electrical characterization of CdSe-PMMA nanocomposite. CdSe-PMMA nanocomposite has been prepared by ex-situ technique through chemical route. The influence of three different Ag doping concentrations on the electrical properties has been studied in the temperature range ∼ 303-353 K. Transmission electron micrograph reveals the spherical morphology of the CdSe nanoparticles and their proper dispersion in the PMMA matrix. The electrical conduction of the polymer nanocomposites is through thermally activated process with single activation energy. With Ag doping, initially the activation energy increases upto 0.2 % Ag doping concentration but with further increase in Ag concentration, it decreases. This behavior has been discussed on the basis of randomly oriented grain boundaries and defect states. Thus, the results indicate that the transport properties of the polymer nanocomposites can be tailored by controlled doping concentration.

Influence of dopant concentration on the electrical properties of the CdSe-PMMA nanocomposite

International Nuclear Information System (INIS)

Kaur, Ramneek; Tripathi, S. K.

2016-01-01

This paper reports the synthesis and electrical characterization of CdSe-PMMA nanocomposite. CdSe-PMMA nanocomposite has been prepared by ex-situ technique through chemical route. The influence of three different Ag doping concentrations on the electrical properties has been studied in the temperature range ∼ 303-353 K. Transmission electron micrograph reveals the spherical morphology of the CdSe nanoparticles and their proper dispersion in the PMMA matrix. The electrical conduction of the polymer nanocomposites is through thermally activated process with single activation energy. With Ag doping, initially the activation energy increases upto 0.2 % Ag doping concentration but with further increase in Ag concentration, it decreases. This behavior has been discussed on the basis of randomly oriented grain boundaries and defect states. Thus, the results indicate that the transport properties of the polymer nanocomposites can be tailored by controlled doping concentration.

Research and development of electric vehicles for clean transportation.

Science.gov (United States)

Wada, Masayoshi

2009-01-01

This article presents the research and development of an electric vehicle (EV) in Department of Human-Robotics Saitama Institute of Technology, Japan. Electric mobile systems developed in our laboratory include a converted electric automobile, electric wheelchair and personal mobile robot. These mobile systems contribute to realize clean transportation since energy sources and devices from all vehicles, i.e., batteries and electric motors, does not deteriorate the environment. To drive motors for vehicle traveling, robotic technologies were applied.

Influence of the electric polarization on carrier transport and recombinaton dynamics in ZnO-based heterostructures

Energy Technology Data Exchange (ETDEWEB)

Brandt, Matthias

2010-08-16

The present thesis deals with the influence of the electric polarization on properties of free carriers in ZnO-based semiconductor heterostructures. Thereby especially transport properties of free carriers as well as their recombination dynamics are studied. The thesis treats four main topics. The first main topic lies on the phsical properties of the applied materials, here the connection of the band gap and the lattice constant of thin Mg{sub x}Zn{sub 1-x}O films and their magnesium content is described. Furthermore the morphology of such films is discussed. Different substrates and deposition conditions are thereby detailedly considered. The second main topic treats the properties of undoped and phosphorus doped thin ZnO and Mg{sub x}Zn{sub 1-x}O films. The structural, transport, and luminescence properties are here compared and conclusions drawn on the growth conditions. In the third main topic quantum effects on ZnO/Mg{sub x}Zn{sub 1-x}O interfaces are treated. Hereby especially the influence of the electric polarization is considered. The presence of a two-dimensional electron gas is proved, and the necessary conditions for the generation of the so-called confined Stark effect are explained. Especially the growth-relevant parameters are considered. The fourth main topic represent coupling phenomena in ZnO/BaTiO{sub 3} heterostructures. Thereby first the experimentally observed properties of different heterostructures are shown, which were grown on different substrates. Here structural and transport properties hold the spotlight. A model for the description of the formation of space-charge zones in such heterostructures is introduced and applied for the description of the experimental results. The usefulness of the ferroelectric properties of the material BaTiO{sub 3} in combination with semiconducting ZnO were studied. For this ferroelectric field effect transistors were fabricated under application of both materials. The principle suitedness of the

Ba doped Fe3O4 nanocrystals: Magnetic field and temperature tuning dielectric and electrical transport

Science.gov (United States)

Dutta, Papia; Mandal, S. K.; Nath, A.

2018-05-01

Nanocrystalline BaFe2O4 has been prepared through low temperature pyrophoric reaction method. The structural, dielectric and electrical transport properties of BaFe2O4 are investigated in detail. AC electrical properties have been studied over the wide range of frequencies with applied dc magnetic fields and temperatures. The value of impedance is found to increase with increase in magnetic field attributing the magnetostriction property of the sample. The observed value of magneto-impedance and magnetodielectric is found to ∼32% and ∼33% at room temperature. Nyquist plots have been fitted using resistance-capacitor circuits at different magnetic fields and temperatures showing the dominant role of grain and grain boundaries of the sample. Metal-semiconductor transition ∼403 K has been discussed in terms of delocalized and localized charge carrier.We have estimated activation energy using Arrhenius relation indicating temperature dependent electrical relaxation process in the system. Ac conductivity follow a Jonscher’s single power law indicating the large and small polaronic hopping conduction mechanism in the system.

Experimental insight into the magnetic and electrical properties of amorphous Ge1-xMnx

Science.gov (United States)

Conta, Gianluca; Amato, Giampiero; Coïsson, Marco; Tiberto, Paola

2017-12-01

We present a study of the electrical and magnetic properties of the amorphous Ge1-xMnx.DMS, with 2% ≤ x ≤ 17%, by means of SQUID magnetometry and low temperature DC measurements. The thin films were grown by physical vapour deposition at 50°C in ultrahigh vacuum. The DC electrical characterizations show that variable range hopping is the main mechanism of charge transport below room temperature. Magnetic characterization reveals that a unique and smooth magnetic transition is present in our samples, which can be attributed to ferromagnetic percolation of bound magnetic polarons.

Two-temperature thermodynamic and transport properties of SF6–Cu plasmas

International Nuclear Information System (INIS)

Wu, Yi; Chen, Zhexin; Yang, Fei; Rong, Mingzhe; Sun, Hao; Cressault, Yann; Murphy, Anthony B; Guo, Anxiang; Liu, Zirui

2015-01-01

SF 6 and Cu are widely adopted in electrical equipment as a dielectric medium and for conductive components, respectively. SF 6 –Cu plasmas are frequently formed, particularly in high-voltage circuit breaker arcs and fault current arcs, due to erosion of the Cu components. In this paper, calculated values of the thermodynamic and transport properties of plasmas in SF 6 –Cu mixtures are presented for both thermal equilibrium and non-equilibrium conditions. The composition is determined by the two-temperature Saha equation and Guldberg–Waage equation in the form derived by van de Sanden. The composition and the thermodynamic properties are evaluated through a classical statistical mechanics approach. For the transport coefficients, the simplified Chapman–Enskog method developed by Devoto, which decouples the electrons and heavy species, has been applied using the most recent collision integrals. The thermodynamic and transport properties are calculated for different electron temperatures (300–40 000 K), ratios of electron to heavy-species temperature (1–10), pressures (0.1–10 atm) and copper molar proportions (0–50%). It is found that deviations from thermal equilibrium strongly affect the thermodynamic and transport properties of the SF 6 –Cu plasmas. Further, the presence of copper has different effects on some of the properties for plasmas in and out of thermal equilibrium. The main reason for these changes is that dissociation reactions are delayed for non-thermal equilibrium plasmas, which in turn influences the ionization reactions that occur. (paper)

Effect of high frequency field on the transport properties of superlattice

International Nuclear Information System (INIS)

Mensah, S.Y.

1992-10-01

Theoretical study of the transport properties of semiconductor superlattice (SL) in the presence of external electric field E(t) has been investigated with the help of Boltzmann's equation. The model adopted agrees fairly well with experimental work as well as Monte Carlo simulation. Among the phenomena observed are the induced self transparency, absolute negative conductivity and the negative differential conductivity. In the case of negative differential conductivity (NDC) it is observed that it does also occur under the a.c. and d.c electric field but appears only when ωτ 0 is equal to the amplitude of the a.c. field E 1 and the peak decreases with an increase in E 1 . (author). 20 refs, 1 fig

Synthesis, Magnetization, and Electrical Transport Properties of Mn3Zn0.9Cu0.1N

Directory of Open Access Journals (Sweden)

Y. Yin

2013-01-01

Full Text Available We synthesized Mn3Zn0.9Cu0.1N by solid state reaction, and magnetic as well as electrical transport properties were investigated. It is found that Mn3Zn0.9Cu0.1N exhibits a first-order antiferromagnetism (AFM to paramagnetic (PM transition with the Néel temperature TN ~163 K, and substitution of Cu for Zn would favor ferromagnetism (FM state and weaken AFM ground state, leading to a convex curvature character of M(T curve. With high external fields 10 kOe–50 kOe, magnetic transition remains a robust AFM-PM feature while FM phase is completely suppressed. Thermal hysteresis of M(T under 500 Oe is also suppressed when the magnetic field exceeds 10 kOe. Mn3Zn0.9Cu0.1N exhibits a good metallic behavior except for a slope change around TN, which is closely related to AFM-PM magnetic transition. Compared with the first differential of resistivity with respect to temperature for (dρ/dTMn3ZnN in transition temperature range, the absolute value of (dρ/dTMn3Zn0.9Cu0.1N is much lower which is close to zero.

High-electric-field quantum transport theory for semiconductor superlattices

International Nuclear Information System (INIS)

Nguyen Hong Shon; Nazareno, H.N.

1995-12-01

Based on the Baym-Kadanoff-Keldysh nonequilibrium Green's functions technique, a quantum transport theory for semiconductor superlattices under high-electric field is developed. This theory is capable of considering collisional broadening, intra-collisional field effects and band transport and hopping regimes simultaneously. Numerical calculations for narrow-miniband superlattices in high electric field, when the hopping regime dominates are in reasonable agreement with experimental results and show a significant deviation from the Boltzmann theory. A semiphenomenological formula for current density in hopping regime is proposed. (author). 60 refs, 4 figs

Electric Field-Controlled Ion Transport In TiO2 Nanochannel.

Science.gov (United States)

Li, Dan; Jing, Wenheng; Li, Shuaiqiang; Shen, Hao; Xing, Weihong

2015-06-03

On the basis of biological ion channels, we constructed TiO2 membranes with rigid channels of 2.3 nm to mimic biomembranes with flexible channels; an external electric field was employed to regulate ion transport in the confined channels at a high ionic strength in the absence of electrical double layer overlap. Results show that transport rates for both Na+ and Mg2+ were decreased irrespective of the direction of the electric field. Furthermore, a voltage-gated selective ion channel was formed, the Mg2+ channel closed at -2 V, and a reversed relative electric field gradient was at the same order of the concentration gradient, whereas the Na+ with smaller Stokes radius and lower valence was less sensitive to the electric field and thus preferentially occupied and passed the channel. Thus, when an external electric field is applied, membranes with larger nanochannels have promising applications in selective separation of mixture salts at a high concentration.

Electric and magnetic fields effects on the transport properties of La0.5Ca0.5MnO3 thin films

International Nuclear Information System (INIS)

Villafuerte, M.; Duhalde, S.; Rubi, D.; Bridoux, G.; Heluani, S.; Sirena, M.; Steren, L.

2004-01-01

The insulator to metal transition in manganites can be drastically influenced by internal factors, such as chemical composition, or under a variety of external perturbations, like magnetic or electric fields. In this work, the electrical resistance of La 0.5 Ca 0.5 MnO 3 thin films was investigated using different constant voltages. At low temperature the conductivity of the films is non-Ohmic and moderate electric fields results in resistivity switching to metastable states. Comparisons between the influence of magnetic and electric fields on transport measurements are reported

Challenges and Opportunities of Grid Modernization and Electric Transportation

Energy Technology Data Exchange (ETDEWEB)

Graham, Robert L. [Dept. of Energy (DOE), Washington DC (United States); Francis, Julieta [Allegheny Science and Technology, Bridgeport, WV (United States); Bogacz, Richard J. [Allegheny Science and Technology, Bridgeport, WV (United States)

2017-03-31

Grid investments that support electric vehicle deployments as a part of planned modernization efforts can enable a more efficient and cost-effective transition to electric transportation and allow investor-owned electric companies and public power companies to realize new revenue resources in times of flat or declining loads. This paper discusses the challenges and opportunities associated with an increase in plug-in electric vehicle (PEV) adoption and how working together both sectors stand to benefit from closer integration.

Electrical and magnetic transport properties of DyTiGe

International Nuclear Information System (INIS)

Dagula, W.; Tegus, O.; Li, X.W.; Zhang, L.; Brueck, E.; Boer, F.R. de; Buschow, K.H.J.

2004-01-01

Electrical resistivity and magnetoresistance of DyTiGe were investigated as a function of temperature and magnetic field. DyTiGe is an antiferromagnet with Neel temperature, T N , of 180 K. The electrical resistivity has an anomaly around T N . Below T N , the magnetoresistance of DyTiGe abruptly changes at a critical field. At 5 K, we observe a magnetoresistance reduction of about 20%

DNA in the material world: electrical properties and nano-applications.

Science.gov (United States)

Triberis, Georgios P; Dimakogianni, Margarita

2009-01-01

Contradictory experimental findings and theoretical interpretations have spurred intense debate over the electrical properties of the DNA double helix. In the present review article the various factors responsible for these divergences are discussed. The enlightenment of this issue could improve long range chemistry of oxidative DNA damage and repair processes, monitoring protein-DNA interactions and possible applications in nano-electronic circuit technology. The update experimental situation concerning measurements of the electrical conductivity is given. The character of the carriers responsible for the electrical conductivity measured in DNA is investigated. A theoretical model for the temperature dependence of the electrical conductivity of DNA is presented, based on microscopic models and percolation theoretical arguments. The theoretical results, excluding or including correlation effects, are applied to recent experimental findings for DNA, considering it as a one dimensional molecular wire. The results indicate that correlation effects are probably responsible for large hopping distances in DNA samples. Other theoretical conductivity models proposed for the interpretation of the responsible transport mechanism are also reviewed. Some of the most known and pioneering works on DNA's nano-applications, future developments and perspectives along with current technological limitations and patents are presented and discussed.

Optical and electrical properties of ZrSe3 single crystals grown by chemical vapour transport technique

International Nuclear Information System (INIS)

Patel, Kaushik; Prajapati, Jagdish; Vaidya, Rajiv; Patel, S.G.

2005-01-01

Single crystals of the lamellar compound, ZrSe 3 , were grown by chemical vapour transport technique using iodine as a transporting agent. The grown crystals were characterized with the help of energy dispersive analysis by X-ray (EDAX), which gave confirmation about the stoichiometry. The optical band gap measurement of as grown crystals was carried out with the help of optical absorption spectra in the range 700-1450 nm. The indirect as well as direct band gap of ZrSe 3 were found to be 1.1 eV and 1.47 eV, respectively. The resistivity of the as grown crystals was measured using van der Pauw method. The Hall parameters of the grown crystals were determined at room temperature from Hall effect measurements. Electrical resistivity measurements were performed on this crystal in the temperature range 303-423 K. The crystals were found to exhibit semiconducting nature in this range. The activation energy and anisotropy measurements were carried out for this crystal. Pressure dependence of electrical resistance was studied using Bridgman opposed anvils set up up to 8 GPa. The semiconducting nature of ZrSe 3 single crystal was inferred from the graph of resistance vs pressure. The results obtained are discussed in detail. (author)

Oxygen nonstoichiometry and transport properties of strontium substituted lanthanum cobaltite

DEFF Research Database (Denmark)

Søgaard, Martin; Hendriksen, Peter Vang; Mogensen, Mogens Bjerg

2006-01-01

Oxygen nonstoichiometry, structure and transport properties of the two compositions (La-0.6 Sr-0.4)(0.99)CoO3-delta (LSC40) and La0.85Sr0.15CoO3-delta (LSC15) were measured. It was found that the oxygen nonstoichiometry as a function of the temperature and oxygen partial pressure could be described...... using the itinerant electron model. The electrical conductivity, sigma, of the materials is high (sigma > 500 S cm(-1)) in the measured temperature range (650 - 1000 degrees C) and oxygen partial pressure range (0.209-10(-4) atm). At 900 degrees C the electrical conductivity is 1365 and 1491 S cm(-1......) in air for LSC40 and LSC15, respectively. A linear correlation between the electrical conductivity and the oxygen vacancy concentration was found for both samples. The mobility of the electron-holes was inversely proportional with the absolute temperature indicating a metallic type conductivity for LSC40...

Electrical transport properties in Co nanocluster-assembled granular film

Science.gov (United States)

Zhang, Qin-Fu; Wang, Lai-Sen; Wang, Xiong-Zhi; Zheng, Hong-Fei; Liu, Xiang; Xie, Jia; Qiu, Yu-Long; Chen, Yuanzhi; Peng, Dong-Liang

2017-03-01

A Co nanocluster-assembled granular film with three-dimensional cross-connection paralleled conductive paths was fabricated by using the plasma-gas-condensation method in a vacuum environment. The temperature-dependent longitudinal resistivity and anomalous Hall effect of this new type granular film were systematically studied. The longitudinal resistivity of the Co nanocluster-assembled granular film first decreased and then increased with increasing measuring temperature, revealing a minimum value at certain temperature, T min . In a low temperature region ( T governed the electrical transport process, and the temperature coefficient of resistance (TCR) showed an insulator-type behavior. The thermal fluctuation-induced tunneling conduction progressively increased with increasing temperature, which led to a decrease in the longitudinal resistivity. In a high temperature region, the TCR showed a metallic-type behavior, which was primarily attributed to the temperature-dependent scattering. Different from the longitudinal resistivity behavior, the saturated anomalous Hall resistivity increased monotonically with increasing measuring temperature. The value of the anomalous Hall coefficient ( R S ) reached 2.3 × 10-9 (Ω cm)/G at 300 K, which was about three orders of magnitude larger than previously reported in blocky single-crystal Co [E. N. Kondorskii, Sov. Phys. JETP 38, 977 (1974)]. Interestingly, the scaling relation ( ρx y A ∝ ρx x γ ) between saturated anomalous Hall resistivity ( ρx y A ) and longitudinal resistivity ( ρ x x ) was divided into two regions by T min . However, after excluding the contribution of tunneling, the scaling relation followed the same rule. The corresponding physical mechanism was also proposed to explain these phenomena.

Effects of interfacial transition layers on the electrical properties of individual Fe 30 Co 61 Cu 9 /Cu multilayer nanowires

KAUST Repository

Ma, Hongbin

2016-01-01

In this work, we accurately measure the electrical properties of individual Fe30Co61Cu9/Cu multilayered nanowires using nanomanipulators in in situ scanning electron microscopy to reveal that interfacial transition layers are influential in determining their transport behaviors. We investigate the morphology, crystal structure and chemistry of the Fe30Co61Cu9/Cu multilayered nanowires to characterize them at the nanoscale. We also compare the transport properties of these multilayered nanowires to those of individual pure Cu nanowires and to those of alloy Fe30Co61Cu9 nanowires. The multilayered nanowires with a 50 nm diameter had a remarkable resistivity of approximately 5.41 × 10-7 Ω m and a failure current density of 1.54 × 1011 A m-2. Detailed analysis of the electrical data reveals that interfacial transition layers influence the electrical properties of multilayered nanowires and are likely to have a strong impact on the life of nanodevices. This work contributes to a basic understanding of the electrical parameters of individual magnetic multilayered nanowires for their application as functional building blocks and interconnecting leads in nanodevices and nanoelectronics, and also provides a clear physical picture of a single multilayered nanowire which explains its electrical resistance and its source of giant magnetoresistance. © The Royal Society of Chemistry 2016.

Influence of functional group on the electrical transport properties of polyvinyl alcohol grafted multiwall carbon nanotube composite thick film

Science.gov (United States)

Kumar Das, Amit; Dharmana, Reuben; Mukherjee, Ayan; Baba, Koumei; Hatada, Ruriko; Kumar Meikap, Ajit

2018-04-01

We present a novel technique to obtain a higher or lower value of dielectric constant due to the variation of a functional group on the surface of multiwall carbon nanotube (MWCNTs) for a polyvinyl alcohol (PVA) grafted MWCNT system. We have prepared PVA grafted pristine and different types of functionalized (-COOH, -OH, and -NH2) MWCNT nanocomposite films. The strong interfacial interaction between the host PVA matrix and nanofiller is characterized by different experimental techniques. The frequency variation of the electrical transport properties of the composite films is investigated in a wide temperature range (303 ≤ T ≤ 413 K) and frequency range (20 Hz ≤ f ≤ 1 MHz). The dielectric constant of the amine (-NH2) functionalized MWCNT incorporated PVA film is about 2 times higher than that of the pristine MWCNT embedded PVA film. The temperature variation of the dielectric constant shows an anomalous behaviour. The modified Cole-Cole equation simulated the experimentally observed dielectric spectroscopy at high temperature. The ac conductivity of the composite films obeys the correlated barrier hopping model. The imaginary part of the electric modulus study shows the ideal Debye-type behaviour at low frequency and deviation of that at high frequency. To illustrate the impedance spectroscopy of the nanocomposite films, we have proposed an impedance based battery equivalent circuit model. The current-voltage characteristic shows hysteresis behaviour of the nanocomposite films. The trap state height for all composite films is evaluated by simulating the current density-electric field data with the Poole-Frenkel emission model. This investigation opens a new avenue for designing electronic devices with a suitable combination of cost effective soft materials.

Optical, electrical and sensing properties of β-ketoimine calix[4]arene thin films

Energy Technology Data Exchange (ETDEWEB)

Echabaane, M., E-mail: mosaab.echabaane@yahoo.fr [Laboratoire des Interfaces et Matériaux Avancés (LIMA), Faculté des Sciences de Monastir, Avenue de l' environnement, 5000 Monastir (Tunisia); Rouis, A. [Laboratoire des Interfaces et Matériaux Avancés (LIMA), Faculté des Sciences de Monastir, Avenue de l' environnement, 5000 Monastir (Tunisia); Bonnamour, I. [Institut de Chimie and Biochimie Moléculaires and Supramoléculaires (ICBMS), UMR CNRS 5246, 43 Boulevard du 11 Novembre 1918, Université Claude Bernard Lyon 1, 69100 Villeurbanne (France); Ben Ouada, H. [Laboratoire des Interfaces et Matériaux Avancés (LIMA), Faculté des Sciences de Monastir, Avenue de l' environnement, 5000 Monastir (Tunisia)

2013-09-16

Optical, electrical and ion sensing properties of β-ketoimine calix[4]arene thin films have been investigated. These calix[4]arene derivative films exhibit absorption spectra with a resolved electronic structure in the UV–vis and the energy gap was found to be 3.65 eV. Electrical properties of ITO/β-ketoimine calix[4]arene/Al devices have been investigated by I–V characteristics and impedance spectroscopy measurements. The conduction is governed by space-charge-limited current (SCLC) mechanism. The impedance spectroscopy study showed a hopping transport process, a typical behavior of disordered materials. The device was modeled by a single parallel resistor and capacitor network in series with a resistance. The β-ketoimine calix[4]arene was used for the conception of the novel optical chemical sensor and the detection of Cu{sup 2+} ions was monitored by UV–visible spectroscopy. The linear dynamic range for the determination of Cu{sup 2+} has been 10{sup −5}–10{sup −3.7} M with a detection limit of 10{sup −5} M. The characteristics of this optode such as regeneration, repeatability, reproducibility, short-term stability, life time and ion selectivity have been discussed. - Highlights: • We examine optical properties of β-ketoimine calix[4]arene ligand. • We investigate the electric properties of ITO/β-ketoimine calix[4]arene/Al device. • We study the sensing properties of optode films for the detection of copper (II)

Electric transport in the Netherlands in an international perspective. Benchmark electric driving 2012

International Nuclear Information System (INIS)

Kroon, P.; Weeda, M.; Appels, D.

2012-07-01

This international benchmark on electric mobility has been conducted to compare the Dutch governmental efforts and developments in the field of electric road transport. The countries that have been considered in this benchmark are: Austria, Belgium, Denmark, France, Germany, the Netherlands, Norway, Portugal, Spain, UK, China, USA and South Korea. The Netherlands has a high ambition level with regard to the number of electric vehicles compared to other countries without a large car industry. As for the envisaged number of charging points, the Netherlands is one of the prominent leaders. In the field of R and D, Germany, South Korea and China take the lead, followed by France, the UK, the USA and Austria. However, the benchmark has only looked at specific funds for electric mobility, and has not looked at general R and D and innovation funds. The Netherlands has several electro-mobility field tests, but is not leading in number. However, regarding general market penetration, the Netherlands is one of the leading countries, next to Norway, based on the relative number of passenger cars and commercial vehicles on the road. Norway and Austria are leading countries when it comes to implementation of public charging infrastructure, but also in this field the Netherlands has a prominent position in the group of countries that follow. In the current pre-commercial phase, the introduction of electric transportation in the Netherlands is supported by a high-level advisory group, the so-called Formula E-Team. This group consists of representatives and experts from industry and (scientific) society, and acts as a figurehead for electric transport. The group advises on coordination of actions to stimulate not only electro- mobility, but also innovation which should lead to new economic activities. Currently, about two hundred companies are already active in the field of electro-mobility in the Netherlands, including some top players and many SMEs (Small Medium Enterprises). The

Electrical transport properties of sputtered Nd2-xCexCuO4±δ thin films

Science.gov (United States)

Guarino, Anita; Leo, Antonio; Avella, Adolfo; Avitabile, Francesco; Martucciello, Nadia; Grimaldi, Gaia; Romano, Alfonso; Pace, Sandro; Romano, Paola; Nigro, Angela

2018-05-01

Thin films of the electron-doped high-temperature superconductor Nd2-xCexCuO4±δ have been deposited by dc sputtering technique on (100) SrTiO3 substrates. A tuning of the oxygen content in the as-grown non-superconducting samples has been achieved by changing the oxygen partial pressure during the growth in the Argon sputtering atmosphere. All samples show the superconducting transition after a suitable two-step thermal treatment in an oxygen-reducing environment. Structural and electrical transport properties on the as-grown as well as on the superconducting samples have been investigated. We find that the structural properties are consistent with a deficiency of the oxygen content with respect to optimally annealed samples, and that the transition to the superconducting phase is always accompanied by an increase of the c-axis lattice parameter. Measurements of the Hall coefficient RH as a function of temperature and in the normal state of our epitaxial films are presented and discussed. RH results negative for all the films regardless of the oxygen content and it decreases with the temperature. In particular, the Hall coefficient is only about 10% lower than the value measured in the as-grown oxygen-deficient phase, in contrast to the results reported in literature. The removal of the excess oxygen in as-grown samples seems not to be the only requirement for triggering the superconducting transition in electron-doped compounds. The microstructural change associated with the increase of the c-axis parameter in our deoxygenated samples could help in understanding the microscopic mechanism underlying the reduction process of n-type superconductors, which is still under debate.

Transport properties of fission product vapors

International Nuclear Information System (INIS)

Im, K.H.; Ahluwalia, R.K.

1983-07-01

Kinetic theory of gases is used to calculate the transport properties of fission product vapors in a steam and hydrogen environment. Provided in tabular form is diffusivity of steam and hydrogen, viscosity and thermal conductivity of the gaseous mixture, and diffusivity of cesium iodide, cesium hydroxide, diatomic tellurium and tellurium dioxide. These transport properties are required in determining the thermal-hydraulics of and fission product transport in light water reactors

Emissions of greenhouse gases from the use of transportation fuels and electricity

International Nuclear Information System (INIS)

DeLuchi, M.A.

1991-11-01

This report presents estimates of full fuel-cycle emissions of greenhouse gases from using transportation fuels and electricity. The data cover emissions of carbon dioxide (CO 2 ), methane, carbon monoxide, nitrous oxide, nitrogen oxides, and nonmethane organic compounds resulting from the end use of fuels, compression or liquefaction of gaseous transportation fuels, fuel distribution, fuel production, feedstock transport, feedstock recovery, manufacture of motor vehicles, maintenance of transportation systems, manufacture of materials used in major energy facilities, and changes in land use that result from using biomass-derived fuels. The results for electricity use are in grams of CO 2 -equivalent emissions per kilowatt-hour of electricity delivered to end users and cover generating plants powered by coal, oil, natural gas, methanol, biomass, and nuclear energy. The transportation analysis compares CO 2 -equivalent emissions, in grams per mile, from base-case gasoline and diesel fuel cycles with emissions from these alternative- fuel cycles: methanol from coal, natural gas, or wood; compressed or liquefied natural gas; synthetic natural gas from wood; ethanol from corn or wood; liquefied petroleum gas from oil or natural gas; hydrogen from nuclear or solar power; electricity from coal, uranium, oil, natural gas, biomass, or solar energy, used in battery-powered electric vehicles; and hydrogen and methanol used in fuel-cell vehicles

Electrical transport properties of MoO3 thin films prepared by laser assisted evaporation

International Nuclear Information System (INIS)

Lopez-Carreno, L.D.; Pardo, A.; Zuluaga, M.; Torres, J.; Alfonso, J.E.; Cortes-Bracho, O.L.

2007-01-01

In the present paper the growth of MoO 3 thin films on common glass substrates are described. The films were prepared by evaporation of a MoO 3 target with a CO 2 laser (10.6 μm), operating in the continuous wave mode. The effect of substrate temperature on the crystallographic structure and electrical properties of MoO 3 thin films was studied. The chemical composition of the different species formed on the films surface was obtained by X-ray photoelectron spectroscopy (XPS) and the crystalline structure was studied with X-ray diffraction (XRD). The electrical conductivity of the films was determined using the standard four-points method. Conductivity of the films varied from de 10 -9 to 10 -5 (Ωcm) -1 in the 300-600 K temperature range. Arrhenius-type plots for the electrical conductivity indicate the presence of at least two different conduction mechanisms. The I-V characteristic curve shows an ohmic behavior only in the 4.5-60 V range. Outside this interval the I-V curve has a behavior described by a power law. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Influence of short range ordering and clustering on transport properties

International Nuclear Information System (INIS)

Vigier, G.; Pelletier, J.M.

1982-01-01

The influence of short range ordering and clustering phenomena on the electrical resistivity p and the thermopower S is investigated both theoretically and experimentally. According to the considered alloys either increases or decreases of transport properties may be observed when deviations from a random distribution of solute atoms occur. These observations are explained with a model based on free electrons and Born approximations the importance of the potential choice is underlined; two kinds of description of the structure factor are investigated. A good semiquantitative agreement is obtained between computed results and experimental observations

The electrical properties of semiconducting vanadium phosphate glasses

International Nuclear Information System (INIS)

Moridi, G.R.; Hogarth, C.A.; Hekmat Shooar, N.H.

1984-01-01

Vanadium phosphate glasses are a group of oxide glasses which show the semiconducting behaviour. In contrast to the conventional glasses, the conduction mechanism in these glasses is electronic, rather than being ionic. Since 1954, when the first paper appeared on the semiconducting properties of these glasses, much work has been carried out on transition-metal-oxide glasses in general, and vanadium phosphate glasses in particular. The mechanism of conduction is basicaly due to the transport of electrons between the transition-metal ions in different valency states. In the present paper, we have reviewed the previous works on the electrical characteristics of P 2 O 5 -V 2 O 5 glasses and also discussed the current theoretical ideas relevant for the interpretation of the experimental data

The influence of Ga{sup +} irradiation on the transport properties of mesoscopic conducting thin films

Energy Technology Data Exchange (ETDEWEB)

Barzola-Quiquia, J; Dusari, S; Bridoux, G; Bern, F; Molle, A; Esquinazi, P, E-mail: j.barzola@physik.uni-leipzig.de, E-mail: esquin@physik.uni-leipzig.de [Division of Superconductivity and Magnetism, Universitaet Leipzig, Linnestrasse 5, D-04103 Leipzig (Germany)

2010-04-09

We studied the influence of 30 keV Ga{sup +}-ions-commonly used in focused-ion-beam (FIB) devices-on the transport properties of thin crystalline graphite flakes, and La{sub 0.7}Ca{sub 0.3}MnO{sub 3} and Co thin films. The changes in electrical resistance were measured in situ during irradiation and also the temperature and magnetic field dependence before and after irradiation. Our results show that the transport properties of these materials strongly change at Ga{sup +} fluences much below those used for patterning and ion-beam-induced deposition (IBID), seriously limiting the use of FIB when the intrinsic properties of the materials of interest are of importance. We present a method that can be used to protect the sample as well as to produce selectively irradiation-induced changes.

Transmembrane molecular transport during versus after extremely large, nanosecond electric pulses.

Science.gov (United States)

Smith, Kyle C; Weaver, James C

2011-08-19

Recently there has been intense and growing interest in the non-thermal biological effects of nanosecond electric pulses, particularly apoptosis induction. These effects have been hypothesized to result from the widespread creation of small, lipidic pores in the plasma and organelle membranes of cells (supra-electroporation) and, more specifically, ionic and molecular transport through these pores. Here we show that transport occurs overwhelmingly after pulsing. First, we show that the electrical drift distance for typical charged solutes during nanosecond pulses (up to 100 ns), even those with very large magnitudes (up to 10 MV/m), ranges from only a fraction of the membrane thickness (5 nm) to several membrane thicknesses. This is much smaller than the diameter of a typical cell (∼16 μm), which implies that molecular drift transport during nanosecond pulses is necessarily minimal. This implication is not dependent on assumptions about pore density or the molecular flux through pores. Second, we show that molecular transport resulting from post-pulse diffusion through minimum-size pores is orders of magnitude larger than electrical drift-driven transport during nanosecond pulses. While field-assisted charge entry and the magnitude of flux favor transport during nanosecond pulses, these effects are too small to overcome the orders of magnitude more time available for post-pulse transport. Therefore, the basic conclusion that essentially all transmembrane molecular transport occurs post-pulse holds across the plausible range of relevant parameters. Our analysis shows that a primary direct consequence of nanosecond electric pulses is the creation (or maintenance) of large populations of small pores in cell membranes that govern post-pulse transmembrane transport of small ions and molecules. Copyright © 2011 Elsevier Inc. All rights reserved.

Electrical transport properties of individual WS2 nanotubes and their dependence on water and oxygen absorption

Science.gov (United States)

Zhang, Chaoying; Ning, Zhiyuan; Liu, Yang; Xu, Tingting; Guo, Yao; Zak, Alla; Zhang, Zhiyong; Wang, Sheng; Tenne, Reshef; Chen, Qing

2012-09-01

The electrical properties of WS2 nanotubes (NTs) were studied through measuring 59 devices. Important electrical parameters, such as the carrier concentration, mobility, and effective barrier height at the contacts, were obtained through fitting experimental non-linear I-V curves using a metal-semiconductor-metal model. The carrier mobility was found to be several orders of magnitude higher than that have been reported previously for WS2 NTs. Water absorption was found to decrease the conductivity and carrier mobility of the NTs, and could be removed when the sample was dried. Oxygen absorption also slightly decreased the conductivity of WS2 NTs.

Inward transport of a toroidally confined plasma subject to strong radial electric fields

Science.gov (United States)

Roth, J. R.; Krawczonek, W. M.; Powers, E. J.; Hong, J.; Kim, Y.

1977-01-01

The paper aims at showing that the density and confinement time of a toroidal plasma can be enhanced by radial electric fields far stronger than the ambipolar values, and that, if such electric fields point into the plasma, radially inward transport can result. The investigation deals with low-frequency fluctuation-induced transport using digitally implemented spectral analysis techniques and with the role of strong applied radial electric fields and weak vertical magnetic fields on plasma density and particle confinement times in a Bumpy Torus geometry. Results indicate that application of sufficiently strong radially inward electric fields results in radially inward fluctuation-induced transport into the toroidal electrostatic potential well; this inward transport gives rise to higher average electron densities and longer particle confinement times in the toroidal plasma.

Investigation of transport properties of FeTe compound

Science.gov (United States)

Lodhi, Pavitra Devi; Solanki, Neha; Choudhary, K. K.; Kaurav, Netram

2018-05-01

Transport properties of FeTe parent compound has been investigated by measurements of electrical resistivity, magnetic susceptibility and Seebeck coefficient. The sample was synthesized through a standard solid state reaction route via vacuum encapsulation and characterized by x-ray diffraction, which indicated a tetragonal phase with space group P4/nmm. The parent FeTe compound does not exhibit superconductivity but shows an anomaly in the resistivity measurement at around 67 K, which corresponds to a structural phase transition along with in the vicinity of a magnetic phase transition. In the low temperature regime, Seebeck coefficient, S(T), exhibited an anomalous dip feature and negative throughout the temperature range, indicating electron-like charge carrier conduction mechanism.

First-principles study on band structures and electrical transports of doped-SnTe

Directory of Open Access Journals (Sweden)

Xiao Dong

2016-06-01

Full Text Available Tin telluride is a thermoelectric material that enables the conversion of thermal energy to electricity. SnTe demonstrates a great potential for large-scale applications due to its lead-free nature and the similar crystal structure to PbTe. In this paper, the effect of dopants (i.e., Mg, Ca, Sr, Ba, Eu, Yb, Zn, Cd, Hg, and In on the band structures and electrical transport properties of SnTe was investigated based on the first-principles density functional theory including spin–orbit coupling. The results show that Zn and Cd have a dominant effect of band convergence, leading to power factor enhancement. Indium induces obvious resonant states, while Hg-doped SnTe exhibits a different behavior with defect states locating slightly above the Fermi level.

Electric field-mediated transport of plasmid DNA in tumor interstitium in vivo.

Science.gov (United States)

Henshaw, Joshua W; Zaharoff, David A; Mossop, Brian J; Yuan, Fan

2007-11-01

Local pulsed electric field application is a method for improving non-viral gene delivery. Mechanisms of the improvement include electroporation and electrophoresis. To understand how electrophoresis affects pDNA delivery in vivo, we quantified the magnitude of electric field-induced interstitial transport of pDNA in 4T1 and B16.F10 tumors implanted in mouse dorsal skin-fold chambers. Four different electric pulse sequences were used in this study, each consisted of 10 identical pulses that were 100 or 400 V/cm in strength and 20 or 50 ms in duration. The interval between consecutive pulses was 1 s. The largest distance of transport was obtained with the 400 V/cm and 50 ms pulse, and was 0.23 and 0.22 microm/pulse in 4T1 and B16.F10 tumors, respectively. There were no significant differences in transport distances between 4T1 and B16.F10 tumors. Results from in vivo mapping and numerical simulations revealed an approximately uniform intratumoral electric field that was predominantly in the direction of the applied field. The data in the study suggested that interstitial transport of pDNA induced by a sequence of ten electric pulses was ineffective for macroscopic delivery of genes in tumors. However, the induced transport was more efficient than passive diffusion.

Effect of External Electric Field on Substrate Transport of a Secondary Active Transporter.

Science.gov (United States)

Zhang, Ji-Long; Zheng, Qing-Chuan; Yu, Li-Ying; Li, Zheng-Qiang; Zhang, Hong-Xing

2016-08-22

Substrate transport across a membrane accomplished by a secondary active transporter (SAT) is essential to the normal physiological function of living cells. In the present research, a series of all-atom molecular dynamics (MD) simulations under different electric field (EF) strengths was performed to investigate the effect of an external EF on the substrate transport of an SAT. The results show that EF both affects the interaction between substrate and related protein's residues by changing their conformations and tunes the timeline of the transport event, which collectively reduces the height of energy barrier for substrate transport and results in the appearance of two intermediate conformations under the existence of an external EF. Our work spotlights the crucial influence of external EFs on the substrate transport of SATs and could provide a more penetrating understanding of the substrate transport mechanism of SATs.

Las aplicaciones del comercio electrónico en un contrato de transporte

Directory of Open Access Journals (Sweden)

Manuel Guillermo Sarmiento

2002-01-01

Full Text Available Colombia es hoy signataria de numerosos convenios internacionales de carácter multilateral sobre el contrato de transporte en sus diversas modalidades; muchos de estos Convenios no admiten la sustitución de los documentos de transporte por medios o sistemas electrónicos de mensaje de datos. Sin embargo, considerando la naturaleza consensual del contrato de transporte, se evidencia que dichos documentos sólo cumplen una función ad-probationem y la nueva ley colombiana de comercio electrónico admite los mensajes de datos como medios de prueba. ¿Cómo armonizar las obligaciones contraídas por el Estado colombiano en virtud de los convenios internacionales antes mencionados con los principios previstos en la ley 527 de 1999 en relación con la admisibilidad y fuerza probatoria de los mensajes de datos? Pueden sustituirse los documentos de transporte por documentos electrónicos? En el presente artículo, un experto en derecho del transporte, responde al interrogante.

Development scheme for the public electricity transport network - 2006-2020

International Nuclear Information System (INIS)

2006-01-01

After having discussed the role of the development scheme and its mains requirements, presented its important components (energy needs, energy transport needs), and described its elaboration mode, this report gives an overview of the present status of the electricity transport network in France: 400.000 volts transport and interconnection networks, 225.000 volts and high voltage networks, development objectives, development context, transport network characteristics in 2006 (country gridding, development dynamics and consumption growth). Then, it presents a set of hypotheses about consumption, production and European exchanges. It identifies different types of constraints (customer connection, supply safety, electric and economic performance, robustness against extreme climate phenomena) and presents a method to assess these constraints (simulation of situations at risk, supply quality analysis, works expertise). The last part present the middle- and long-term constraints for the network

Effect of spin-orbit interactions on the structural stability, thermodynamic properties, and transport properties of lead under pressure

Science.gov (United States)

Smirnov, N. A.

2018-03-01

The paper investigates the role of spin-orbit interaction in the prediction of structural stability, lattice dynamics, elasticity, thermodynamic and transport properties (electrical resistivity and thermal conductivity) of lead under pressure with the FP-LMTO (full-potential linear-muffin-tin orbital) method for the first-principles band structure calculations. Our calculations were carried out for three polymorphous lead modifications (fcc, hcp, and bcc) in generalized gradient approximation with the exchange-correlation functional PBEsol. They suggest that compared to the scalar-relativistic calculation, the account for the SO effects insignificantly influences the compressibility of Pb. At the same time, in the calculation of phonon spectra and transport properties, the role of SO interaction is important, at least, for P ≲150 GPa. At higher pressures, the contribution from SO interaction reduces but not vanishes. As for the relative structural stability, our studies show that SO effects influence weakly the pressure of the fcc →hcp transition and much higher the pressure of the hcp →bcc transition.

ELECTRICAL PROPERTIES OF DC REACTIVE MAGNETRON ...

African Journals Online (AJOL)

Mgina

value of the AC resistivity was given by the ZnO:Al film with the highest value of ... Compared to other thin film ... critical parameters in determining the ... approach in studying the electronic transport ..... J 2009 Electrical and optical studies of.

Vision on Scarcity of Transportation. Policy with regard to scarcity of transportation capacity in the electricity grid

International Nuclear Information System (INIS)

Bruin, K.; Fransen, M.; Kranenburg, J.

2009-01-01

The Dutch Competitive Authority NMa established increasing problems that are related to the (possible future) scarcity in transportation capacity in the electricity grid. This vision document aims to inform market parties about the general vision of NMa in relation to the scarcity issue. This document first addresses the problems related to scarcity in transport capacity in the electricity grid. Next policy developments in this area are discussed and NMa's vision is elaborated and explained [nl

Structural, dielectric and electrical properties of ...

Indian Academy of Sciences (India)

Administrator

Detailed studies of dielectric properties of the compound as a function of temperature at ... Microscope (Jeol, JSM-840), operated at 20 kV. The sin- tered pellet was .... grain boundaries, and provides the true picture of the electrical properties of ...

Electrical properties of materials

CERN Document Server

Solymar, L; Syms, R R A

2014-01-01

An informal and highly accessible writing style, a simple treatment of mathematics, and clear guide to applications have made this book a classic text in electrical and electronic engineering. Students will find it both readable and comprehensive. The fundamental ideas relevant to the understanding of the electrical properties of materials are emphasized; in addition, topics are selected in order to explain the operation of devices having applications (or possible future applications) in engineering. The mathematics, kept deliberately to a minimum, is well within the grasp of a second-year student. This is achieved by choosing the simplest model that can display the essential properties of a phenomenom, and then examining the difference between the ideal and the actual behaviour. The whole text is designed as an undergraduate course. However most individual sections are self contained and can be used as background reading in graduate courses, and for interested persons who want to explore advances in microele...

ELECTROMAGNETIC SAFETY OF ELECTRIC TRANSPORT SYSTEMS: MAIN SOURCES AND PARAMETERS OF MAGNETIC FIELDS

Directory of Open Access Journals (Sweden)

N. G. Ptitsyna

2013-03-01

Full Text Available Magnetic fields produced by electric drive vehicles may break electromagnetic safety. For electromagnetic safety and electromagnetic compatibility knowledge about characteristics and sources of magnetic fields in the electric transport is necessary. The article deals with analysis of available data about magnetic fields in electric cars and comparison with results of our measurements carried out in the other types of electrified transport systems.

Influence of pressing on the nanostructure and electrical properties of semiconducting polymer nanolayers

International Nuclear Information System (INIS)

Park, Jiho; Kim, Hwajeong; Kim, Youngkyoo

2010-01-01

In this work we attempted to change the nanostructure and electrical properties of semiconducting polymer nanolayers by employing a nano-pressing technique. The semiconducting polymer nanolayers, which consist of poly(3-hexylthiophene) (P3HT) and 1-(3-methoxycarbonyl)-propyl-1-phenyl-(6,6)C 61 (PCBM), were spin-coated on to a conducting polymer buffer layer coated on a transparent conducting oxide substrate. The coated P3HT:PCBM samples were precisely pressed using a nanopress system at 70 .deg. C. The nanostructures of the unpressed and the pressed P3HT:PCBM layers were investigated using a grazing incident angle X-ray diffraction (GIXD) system empowered by a synchrotron radiation source while the electrical properties of those samples were examined using a diode-type device. Results showed that the P3HT chain alignment was improved by pressing, accordingly, the device with the pressed layer exhibited enhanced charge transport characteristics.

Magnetic and transport properties of Fe-based nanocrystalline materials

Science.gov (United States)

Barandiarán, J. M.

1994-01-01

Fe-rich amorphous alloys containing late transition metals like Nb, V, Zr,..., sometimes with the addition of Cu, can crystallize in ultrafine grains of a crystalline phase, a few nanometers in diameter, embedded in a disordered matrix. In such state they have shown excellent soft magnetic properties for technical applications, rising the interest for deep studies. In this paper, recent work on some Fe-Nb and Fe-Zr based alloys both in amorphous state and after several degrees of nanocrystallization is presented. The nanocrystallization process has been achieved by conventional heat treatments (about 1 h at temperatures around 400-500 °C in a controlled atmosphere furnance) as well as by Joule heating using an electrical current flowing through the sample. Magnetic measurements, electrical resistivity, x-rays diffraction and 57Fe Mössbauer spectroscopy were used in the study of the crystalline phases appearing after the thermal treatments. The basic magnetic and transport properties of the nanocrystals do not differ appreciably from their bulk values. The magnetic anisotropy, however, is very sensitive to grain size and to the intergranular magnetic coupling. The effect of such coupling is deduced from the coercivity changes at the Curie Temperature of the amorphous matrix remaining after nanocrystallization.

Electric generation and ratcheted transport of contact-charged drops

Science.gov (United States)

Cartier, Charles A.; Graybill, Jason R.; Bishop, Kyle J. M.

2017-10-01

We describe a simple microfluidic system that enables the steady generation and efficient transport of aqueous drops using only a constant voltage input. Drop generation is achieved through an electrohydrodynamic dripping mechanism by which conductive drops grow and detach from a grounded nozzle in response to an electric field. The now-charged drops are transported down a ratcheted channel by contact charge electrophoresis powered by the same voltage input used for drop generation. We investigate how the drop size, generation frequency, and transport velocity depend on system parameters such as the liquid viscosity, interfacial tension, applied voltage, and channel dimensions. The observed trends are well explained by a series of scaling analyses that provide insight into the dominant physical mechanisms underlying drop generation and ratcheted transport. We identify the conditions necessary for achieving reliable operation and discuss the various modes of failure that can arise when these conditions are violated. Our results demonstrate that simple electric inputs can power increasingly complex droplet operations with potential opportunities for inexpensive and portable microfluidic systems.

Effect of the metal work function on the electrical properties of carbon nanotube network transistors

International Nuclear Information System (INIS)

Kim, Un Jeong; Ko, Dae Young; Kil, Joon Pyo; Lee, Jung Wha; Park, Wan Jun

2012-01-01

A nearly perfect semiconducting single-walled carbon nanotube random network thin film transistor array was fabricated, and its reproducible transport properties were investigated. The effects of the metal work function for both the source and the drain on the electrical properties of the transistors were systematically investigated. Three different metal electrodes, Al, Ti, and Pd, were employed. As the metal work function increased, p-type behavior became dominant, and the field effect hole mobility dramatically increased. Also, the Schottky barrier of the Ti-nanotube contact was invariant to the molecular adsorption of species in air.

Curvature effects on the electronic and transport properties of semiconductor films

Science.gov (United States)

Batista, F. F.; Chaves, Andrey; da Costa, D. R.; Farias, G. A.

2018-05-01

Within the effective mass approximation, we study the curvature effects on the electronic and transport properties of semiconductor films. We investigate how the geometry-induced potential resulting exclusively from periodic ripples in the film induces electronic confinement and a superlattice band structure. For fixed curvature parameters, such a confinement can be easily tuned by an external electric field, hence features of the superlattice band structure such as its energy gaps and band curvature can be controlled by an external parameter. We also show that, for some values of curvature and electric field, it is possible to obtain massless Dirac bands for a smooth curved structure. Moreover, we use a wave packet propagation method to demonstrate that the ripples are responsible for a significant inter-sub-band transition, specially for moderate values of the ripple height.

Characterization of structural and electrical properties of ZnO tetrapods

Science.gov (United States)

Gu, Yu-Dong; Mai, Wen-Jie; Jiang, Peng

2011-12-01

ZnO tetrapods were synthesized by a typical thermal vapor-solid deposition method in a horizontal tube furnace. Structural characterization was carried out by transmission electron microscopy (TEM) and select-area electron diffraction (SAED), which shows the presence of zinc blende nucleus in the center of tetrapods while the four branches taking hexagonal wurtzite structure. The electrical transport property of ZnO tetrapods was investigated through an in-situ nanoprobe system. The three branches of a tetrapod serve as source, drain, and "gate", respectively; while the fourth branch pointing upward works as the force trigger by vertically applying external force downward. The conductivity of each branch of ZnO-tetrapods increases 3-4 times under pressure. In such situation, the electrical current through the branches of ZnO tetrapods can be tuned by external force, and therefore a simple force sensor based on ZnO tetrapods has been demonstrated for the first time.

Two-dimensional carbon crystals. Electrical transport in single- and double-layer graphene; Zweidimensionale Kohlenstoffkristalle. Elektrischer Transport in Einzel- und Doppellagen-Graphen

Energy Technology Data Exchange (ETDEWEB)

Schmidt, Hennrik

2012-02-03

In his work atomically thin layers of carbon, socalled graphene, are investigated. These systems exhibit outstanding electronic properties which are analysed using magnetotransport measurements. For this purpose, different types of samples are prepared, analysed and discussed. In addition to conventional single layer and single crystal bilayer systems, folded flakes with twisted planes are examined. Since monolayer graphene is a two dimensional crystal in which every atom sits at the surface, it is very sensitive to any type of perturbation. Three different cases are investigated: Firstly, dopants are removed from the surface and the change in transport properties is monitored. Secondly, the regime of small carrier concentrations is used to observe field induced recharging of inhomogeneities. Thirdly, an atomic force microscope is used to alter the graphene itself in a defined region. The implications of this modification are again investigated using magnetotransport measurements. The influence of one layer on another one is studied in decoupled two layer samples. A folded sample with separatly contacted layers is used to show transport through the folded region. For jointly contacted layers parallel transport measurements are performed to analyse screening effects of an applied electric field and substrate influence. The interaction of the two layers is shown by a significant reduction of the Fermivelocity.

The low temperature specific heat and electrical transport, magnetic properties of Pr{sub 0.65}Ca{sub 0.35}MnO{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Han, Zhiyong, E-mail: zyhan@cauc.edu.cn

2017-02-01

The magnetic properties, electrical transport properties, and low temperature specific heat of polycrystalline perovskite manganese oxide Pr{sub 0.65}Ca{sub 0.35}MnO{sub 3} have been investigated experimentally. It is found that there exists cluster glass state in the sample at low temperature besides the antiferromagnetic insulating state. With the increase of magnetic field, antiferromagnetic insulating state converts to ferromagnetic metal state and the Debye temperature decreases gradually. In addition, the low temperature electron specific heat in zero magnetic field is obviously larger than that of ordinary rare-earth manganites oxide and this phenomenon is related to the itinerant electrons in ferromagnetic cluster state and the disorder in Pr{sub 0.65}Ca{sub 0.35}MnO{sub 3}. - Highlights: • There exists cluster glass state in the sample at low temperature besides the antiferromagnetic insulating state. • With the increase of magnetic field, antiferromagnetic insulating state converts to ferromagnetic metal state. • Low temperature electron specific heat in zero magnetic field is larger than that of ordinary rare-earth manganites oxide.

Interface effects on the electronic transport properties in highly epitaxial LaBaCo2O(5.5+δ) films.

Science.gov (United States)

Ma, C R; Liu, M; Liu, J; Collins, G; Zhang, Y M; Wang, H B; Chen, C L; Lin, Y; He, J; Jiang, J C; Meletis, E I; Jacobson, A J

2014-02-26

Single-crystalline perovskite LaBaCo2O5.5+δ thin films were grown on a (110) NdGaO3 single-crystal substrate in order to systematically investigate the effect of lattice mismatch on the electrical transport properties in comparison to the films on LaAlO3, SrTiO3, and MgO substrates. Microstructure studies reveal that all of the LaBaCo2O5.5+δ films are of excellent quality with atomically sharp interface structures. The electrical and magnetic transport property studies indicate that the resistivity, magnetoresistance, and magnetic moment of the film are very sensitive to the substrate materials because of the lattice mismatch/interface strain. The Curie temperature, however, is almost independent of the strain imposed by the substrate, probably because of the strong coupling between the nanodomain boundary and interface strain.

Defect chemistry of ''BaCuO2''. Pt. 2. Transport properties and nature of defects

International Nuclear Information System (INIS)

Chiodelli, G.; Consiglio Nazionale delle Ricerche, Pavia; Anselmi-Tamburini, U.; Consiglio Nazionale delle Ricerche, Pavia; Arimondi, M.; Consiglio Nazionale delle Ricerche, Pavia; Spinolo, G.; Consiglio Nazionale delle Ricerche, Pavia; Flor, G.; Consiglio Nazionale delle Ricerche, Pavia

1995-01-01

The charge transport properties of ''BaCuO 2 '' with 88:90 (Ba:Cu) cation ratio were characterized by thermopower, electrical conductivity and ionic transport number measurements in a wide range of temperature and oxygen partial pressure conditions. The nature of carriers is always represented by small polarons due to self-trapping of the electronic holes generated by the oxygen non-stoichiometry equilibrium. Some anomalies in carrier mobility as a function of temperature are shown not to be related to incomplete ionization of oxygen atoms on interstitial sites (orig.)

Ab initio theories of electric transport in solid systems with reduced dimensions

International Nuclear Information System (INIS)

Weinberger, Peter

2003-01-01

Ab initio theories of electric transport in solid systems with reduced dimensions, i.e., systems that at best are characterized by two-dimensional translational invariance, are reviewed in terms of a fully relativistic description of the Kubo-Greenwood equation. As the use of this equation requires concepts such as collinearity and non-collinearity in order to properly define resistivities or resistances corresponding to particular magnetic configurations, respective consequences of the (local) density functional theory are recalled in quite a detailed manner. Furthermore, since theoretical descriptions of solid systems with reduced dimensions require quantum mechanical methods different from bulk systems (three-dimensional periodicity), the so-called Screened Korringa-Kohn-Rostoker (SKKR-) method for layered systems is introduced together with a matching coherent potential approximation (inhomogeneous CPA). The applications shown are mainly meant to illustrate various aspects of electric transport in solid systems with reduced dimensions and comprise not only current-in-plane (CIP) experiments, but also current perpendicular to the planes of atoms geometries, consequences of tunneling, and finite nanostructures at or on metallic substrates. In order to give a more complete view of available ab initio methods also a non-relativistic approach based on the Tight Binding Linear Combination of muffin tin orbitals (TB-LMTO-) method and the so-called Kubo-Landauer equation in terms of transmission and reflection matrices is presented. A compilation of references with respect to ab-initio type approaches not explicitly discussed in here finally concludes the discussion of electric properties in solid systems with reduced dimensions

Studies on transport properties of copper doped tungsten diselenide single crystals

Science.gov (United States)

Deshpande, M. P.; Parmar, M. N.; Pandya, Nilesh N.; Chaki, Sunil; Bhatt, Sandip V.

2012-02-01

During recent years, transition metal dichalcogenides of groups IVB, VB and VIB have received considerable attention because of the great diversity in their transport properties. 2H-WSe 2 (Tungsten diselenide) is an interesting member of the transition metal dichalcogenide (TMDC's) family and known to be a semiconductor useful for photovoltaic and optoelectronic applications. The anisotropy usually observed in this diamagnetic semiconductor material is a result of the sandwich structure of Se-W-Se layers interacting with each other, loosely bonded by the weak Van der Waals forces. Recent efforts in studying the influence of the anisotropic electrical and optical properties of this layered-type transition metal dichalcogenides have been implemented by doping the samples with different alkali group elements. Unfortunately, little work is reported on doping of metals in WSe 2. Therefore, it is proposed in this work to carry out a systematic growth of single crystals of WSe 2 by doping it with copper in different proportions i.e. Cu xWSe 2 ( x=0, 0.5, 1.0) by direct vapour transport technique. Transport properties like low and high temperature resistivity measurements, high pressure resistivity, Seebeck coefficient measurements at low temperature and Hall Effect at room temperature were studied in detail on all these samples. These measurements show that tungsten diselenide single crystals are p-type whereas doped with copper makes it n-type in nature. The results obtained and their implications are discussed in this paper.

Electricity as Transportation ``Fuel''

Science.gov (United States)

Tamor, Michael

2013-04-01

The personal automobile is a surprisingly efficient device, but its place in a sustainable transportation future hinges on its ability use a sustainable fuel. While electricity is widely expected to be such a ``fuel,'' the viability of electric vehicles rests on the validity of three assumptions. First, that the emissions from generation will be significantly lower than those from competing chemical fuels whether `renewable' or fossil. Second, that advances in battery technology will deliver adequate range and durability at an affordable cost. Third, that most customers will accept any functional limitations intrinsic to electrochemical energy storage. While the first two are subjects of active research and vigorous policy debate, the third is treated virtually as a given. Popular statements to the effect that ``because 70% of all daily travel is accomplished in less than 100 miles, mass deployment of 100 mile EVs will electrify 70% of all travel'' are based on collections of one-day travel reports such as the National Household Travel Survey, and so effectively ignore the complexities of individual needs. We have analyzed the day-to-day variations of individual vehicle usage in multiple regions and draw very different conclusions. Most significant is that limited EV range results in a level of inconvenience that is likely to be unacceptable to the vast majority of vehicle owners, and for those who would accept that inconvenience, battery costs must be absurdly low to achieve any economic payback. In contrast, the plug-in hybrid (PHEV) does not suffer range limitations and delivers economic payback for most users at realistic battery costs. More importantly, these findings appear to be universal in developed nations, with labor market population density being a powerful predictor of personal vehicle usage. This ``scalable city'' hypothesis may prove to a powerful predictor of the evolution of transportation in the large cities of the developing world.

Electrical transverse transport in Lorentz plasma with strong magnetic field and collision effect

International Nuclear Information System (INIS)

Xie, Baisong; Chong, L.V.; Li, Ziliang

2015-01-01

In inertial confinement fusion (ICF), the spontaneous magnetic field formed from laser interacting with the pellet may reach few hundreds of Megagauss (MG) which results in the cyclotron frequency ω at the same order of the collision frequency υ. Electrical transverse transport in this case would become very important so that we study it by the Boltzmann equation for different electron density distribution. For the Maxwell distribution, it is shown that transport coefficients decrease with the increase of Ω (the ratio of ω to υ), which means the electrons would be highly collimated by strong magnetic field. This is attributed to that the electron's gyroradius is smaller than the collisional mean free paths. Moreover, the electrical transverse transport is also studied for quasi-monoenergy distribution with different width ε, which is different from the Maxwell one. It is found that the transport coefficients decrease greatly as quasi-monoenergy degree increases. In particular when ε approaches to zero, i.e. the Delta distribution with almost perfect monoenergy electron density, the electric conductivity doesn't change while the thermal conductivity decreases with Ω. On the other hand the smaller the ε is the less amount the transverse transport exhibits. Our study indicates that they are beneficial to limit the electric transverse transport. (author)

Transport analysis of radial electric field in helical plasmas

International Nuclear Information System (INIS)

Toda, S.; Itoh, K.

2004-01-01

A set of transport equations is analyzed which induces the radial transition of the electric field. A temperature profile which is related with the transport barrier is obtained by use of the theoretical model for the anomalous transport diffusivities. A dependence on the different initial condition is found even if the same values of the control parameters are used in calculations. A study of the temporal evolution of E r is done. We examine the test of the adopted theoretical model for the anomalous transport diffusivities compared with the experimental result in Large Helical Device (LHD). (authors)

Decarbonising the Swedish transport sector with electricity or biofuels

DEFF Research Database (Denmark)

Pedersen, Rasmus Bo Bramstoft; Skytte, Klaus

2016-01-01

Sweden has set long-term energy policy targets which aim at eliminating net greenhouse gas (GHG) emissions by 2050 [1]. Since the production of power and district heating in Sweden is already close to be carbon neutral, a further reduction of GHG emissions have to be seeked in other sectors......, if the ambitious targets of a carbon neutral transport system by 2050 and of being independent from fossil fuels in the vehicle fleet by 2030 have to be achieved [1]. To meet the energy policy targets, radical restructuring of the fuel use and vehicle stock in the transport sector is required. In this context......, this paper develops two alternative scenarios for the transport sector by 2050 – an Electric Vehicles Scenario (EVS) which include a high percentage of electric vehicles and a BIOfuel Scenario (BIOS) with a high percentage of biofuels. The scenario results are compared to the Carbon Neutral Scenario (CNS...

Decarbonising the Finnish Transport Sector by 2050: Electricity or Biofuels?

DEFF Research Database (Denmark)

Skytte, Klaus; Bramstoft Pedersen, Rasmus

2018-01-01

for the transport sector by 2050—one with a high percentage of electric vehicles (EV) and another with a high percentage of biofuels (BIO), and compares the scenario results with a known Carbon-Neutral Scenario (CNS) which is adopted from the Nordic Energy Technology Perspective (IEA in Nordic energy technology...... perspective—pathways to a carbon-neutral energy future, 2013a). The socio-economic value of the total system cost is computed and the system integration of the transport sector with the electricity and heating sectors is simulated with an hourly time resolution. This study finds that a Finnish transport...... of the results is tested through a sensitivity analysis which shows that the costs (investment and maintenance) of biodiesel cars and EV are the most sensitive parameters in the comparative analysis of the scenarios....

Electronic transport properties of nanostructured MnSi-films

Science.gov (United States)

Schroeter, D.; Steinki, N.; Scarioni, A. Fernández; Schumacher, H. W.; Süllow, S.; Menzel, D.

2018-05-01

MnSi, which crystallizes in the cubic B20 structure, shows intriguing magnetic properties involving the existence of skyrmions in the magnetic phase diagram. Bulk MnSi has been intensively investigated and thoroughly characterized, in contrast to MnSi thin film, which exhibits widely varying properties in particular with respect to electronic transport. In this situation, we have set out to reinvestigate the transport properties in MnSi thin films by means of studying nanostructure samples. In particular, Hall geometry nanostructures were produced to determine the intrinsic transport properties.

Transport of electric charge in insulators

International Nuclear Information System (INIS)

Lopez C, E.

1979-01-01

In this work a review is made of important concepts in the study of the transport of electric charge in insulators. These concepts are: electrical contacts, transport regimes as viewed in the I-V characteristics, and photoinjection processes by internal photemission of holes or electrons from metals or semiconductors into insulators or by a virtual electrode using strongly absorbed light. Experimental results of photoinjection of holes and electrons into sulfur single crystals are analyzed using these concepts. The observation of the Mott-Gurney transition is reported for the first time. This is the transition between the region of space charge limited currents (SCLC) and the region of saturation of the current as a function of the applied voltage. A modified Mott-Gurney theoretical model is presented that is able to explain the whole I-V characteristic for uv and the internal photoemission of hopes and uv photoinjection of electrons. For the case of internal photoemission of electrons the conventional space charge limited current theory for an exponential distribution of traps is able to explain the experimental data. It is found that the crystals are of high purity since the total density of traps, as calculated from their exponential distribution, is Nsub(t) equals 1.8 X 10 14 cm -3 . (author)

Application of column tests and electrical resistivity methods for leachate transport monitoring

Directory of Open Access Journals (Sweden)

Wychowaniak Dorota

2015-09-01

Full Text Available Development of the human civilization leads to the pollution of environment. One of the contamination which are a real threat to soil and groundwater are leachates from landfills. In this paper the solute transport through soil was considered. For this purpose, the laboratory column tests of chlorides tracer and leachates transport on two soil samples have been carried out. Furthermore, the electrical resistivity method was applied as auxiliary tool to follow the movements of solute through the soil column what allowed to compare between the results obtained with column test method and electrical resistivity measurements. Breakthrough curves obtained by conductivity and resistivity methods represents similar trends which leads to the conclusion about the suitability of electrical resistivity methods for contamination transport monitoring in soil-water systems.

Effects of surface morphology on the optical and electrical properties of Schottky diodes of CBD deposited ZnO nanostructures

Science.gov (United States)

Mwankemwa, Benard S.; Akinkuade, Shadrach; Maabong, Kelebogile; Nel, Jackie M.; Diale, Mmantsae

2018-04-01

We report on effect of surface morphology on the optical and electrical properties of chemical bath deposited Zinc oxide (ZnO) nanostructures. ZnO nanostructures were deposited on the seeded conducting indium doped tin oxide substrate positioned in three different directions in the growth solution. Field emission scanning electron microscopy was used to evaluate the morphological properties of the synthesized nanostructures and revealed that the positioning of the substrate in the growth solution affects the surface morphology of the nanostructures. The optical absorbance, photoluminescence and Raman spectroscopy of the resulting nanostructures are discussed. The electrical characterization of the Schottky diode such as barrier height, ideality factor, rectification ratios, reverse saturation current and series resistance were found to depend on the nanostructures morphology. In addition, current transport mechanism in the higher forward bias of the Schottky diode was studied and space charge limited current was found to be the dominant transport mechanism in all samples.

Transport properties of Nd0.67Sr0.33Mn0.85Co0.15O3 manganite

Science.gov (United States)

Bhargav, Abhinav; Tank, Tejas M.; Sanyal, Sankar P.

2018-05-01

We have studied the structural and electrical transport properties of Nd0.67Sr0.33Mn0.85Co0.15O3 manganite prepared through conventional solid state reaction technique. The investigation of X-ray diffraction data and rietvield refinement show that the synthesized sample is single phase in nature and crystallizes in orthorhombic perovskite structure with Pbnm space group. The resistivity versus temperature measurement for sample Nd0.67Sr0.33Mn0.85Co0.15O3 was performed in the range 0-300K and at 0T field. The electrical transport mechanism of the sample is analyzed by different theoretical models, for temperatures below and above TP.

Nanocluster-rich SiO2 layers produced by ion beam synthesis: electrical and optoelectronic properties

International Nuclear Information System (INIS)

Gebel, T.

2002-07-01

The main goal of this work is to investigate correlations between microstructural, electrical and optical properties of the devices. Chapter 3 gives an overview about the fabrication process and the methods used for the characterization of the devices. The microstructure of the devices is described in chapter 4 and the results of electrical and optical investigations are presented in chapter 5 and 6, respectively. The aim of the investigations is to get a better understanding of the charge transport, the charge storage and the mechanism of the electroluminescence. This knowledge is necessary for the further optimization of the devices and for possible applications. (orig.)

TRANSPORT PROPERTIES FOR REFRIGERANT MIXTURES

Directory of Open Access Journals (Sweden)

V. Geller

2014-06-01

Full Text Available A set of models to predict viscosity and thermal conductivity of refrigerant mixtures is developed. A general model for viscosity and thermal conductivity use the three contributions sum form (the dilute-gas terms, the residual terms, and the liquid terms. The corresponding states model is recommended to predict the dense gas transport properties over a range of reduced density from 0 to 2. It is shown that the RHS model provides the most reliable results for the saturated-liquid and the compressed-liquid transport properties over a range of given temperatures from 0,5 to 0,95.

A methodology for extracting the electrical properties of human skin

International Nuclear Information System (INIS)

Birgersson, Ulrik; Nicander, Ingrid; Ollmar, Stig; Birgersson, Erik

2013-01-01

A methodology to determine dielectrical properties of human skin is presented and analyzed. In short, it is based on a mathematical model that considers the local transport of charge in the various layers of the skin, which is coupled with impedance measurements of both stripped and intact skin, an automated code generator, and an optimization algorithm. New resistivity and permittivity values for the stratum corneum soaked with physiological saline solution for 1 min and the viable skin beneath are obtained and expressed as easily accessible functions. The methodology can be extended to account for different electrode designs as well as more physical phenomena that are relevant to electrical impedance measurements of skin and their interpretation. (paper)

Quantum oscillations and the electronic transport properties in multichain nanorings

International Nuclear Information System (INIS)

Racolta, D.

2009-01-01

We consider a system of multichain nanorings in static electric and magnetic field. The magnetic field induces characteristic phase changes. These phase shifts produce interference phenomena in the case of nanosystems for which the coherence length is larger than the sample dimension. We obtain energy solutions that are dependent on the number of sites N α characterizing a chain, of phase on the phase φ α and on the applied voltage. We found rich oscillations structures exhibited by the magnetic flux and we established the transmission probability. This proceeds by applying Landauer conductance formulae which opens the way to study electronic transport properties. (authors)

Quantifying solute transport processes: are chemically "conservative" tracers electrically conservative?

Science.gov (United States)

Singha, Kamini; Li, Li; Day-Lewis, Frederick D.; Regberg, Aaron B.

2012-01-01

The concept of a nonreactive or conservative tracer, commonly invoked in investigations of solute transport, requires additional study in the context of electrical geophysical monitoring. Tracers that are commonly considered conservative may undergo reactive processes, such as ion exchange, thus changing the aqueous composition of the system. As a result, the measured electrical conductivity may reflect not only solute transport but also reactive processes. We have evaluated the impacts of ion exchange reactions, rate-limited mass transfer, and surface conduction on quantifying tracer mass, mean arrival time, and temporal variance in laboratory-scale column experiments. Numerical examples showed that (1) ion exchange can lead to resistivity-estimated tracer mass, velocity, and dispersivity that may be inaccurate; (2) mass transfer leads to an overestimate in the mobile tracer mass and an underestimate in velocity when using electrical methods; and (3) surface conductance does not notably affect estimated moments when high-concentration tracers are used, although this phenomenon may be important at low concentrations or in sediments with high and/or spatially variable cation-exchange capacity. In all cases, colocated groundwater concentration measurements are of high importance for interpreting geophysical data with respect to the controlling transport processes of interest.

Investigating the effect of acene-fusion and trifluoroacetyl substitution on the electronic and charge transport properties by density functional theory

Directory of Open Access Journals (Sweden)

Ahmad Irfan

2016-05-01

Full Text Available We designed novel derivatives of 4,6-di(thiophen-2-ylpyrimidine (DTP. Two benchmark strategies including mesomerically deactivating group, as well as the extension of π-conjugation bridge (acene-fusion have been employed to enhance the electrical and charge transport properties. The density functional theory (DFT and time dependent DFT methods have been used to get optimized geometries in ground and first excited state, respectively. The structural properties (geometric parameters, electronic properties (frontier molecular orbitals; highest occupied and lowest unoccupied molecular orbitals, photophysical properties (absorption, fluorescence and phosphorescence, and important charge transport properties are discussed to establish a molecular level structure–property relationship among these derivatives. Our calculated electronic spectra i.e., absorption, fluorescence and phosphorescence have been found in good semi-quantitative agreement with available experimental data. All the newly designed derivatives displayed significantly improved electron injection ability than those of the parent molecule. The values of reorganization energy and transfer integral elucidate that DTP is a potential hole transport material. Based on our present investigation, it is expected that the naphtho and anthra derivatives of DTP are better hole transporters than those of some well-known charge transporter materials like naphthalene, anthracene, tetracene and pentacene.

Thermodynamic and transport properties of YbNi 4Cd

Science.gov (United States)

Lee, J.; Park, H.; Lee-Hone, N. R.; Broun, D. M.; Mun, E.

2018-05-01

The single crystal growth and the physical properties of the intermetallic compounds R Ni4Cd (R =Y and Yb) which crystallize in the face-centered cubic (fcc) MgCu4Sn -type structure (space group F 4 ¯3 m ) are discussed. Thermodynamic and transport properties of YbNi4Cd are studied by measuring the magnetization, electrical resistivity, and specific heat. The magnetic susceptibility measurement shows that the 4 f electrons of Yb3 + ions are well localized. The electrical resistivity and specific heat exhibits an antiferromagnetic ordering below TN=0.97 K. Applying the field along the [111] direction results in the suppression of TN below 0.4 K at the critical field Hc˜4.5 kOe. No non-Fermi liquid behavior has been observed in the vicinity of Hc. Above Hc, the magnetoresistivity shows an unconventional temperature dependence ρ (T ) =ρ0+A Tn with n >2 , suggesting that an additional scattering mechanism in the resistivity needs to be considered. Based on the analysis of experimental results, we conclude that the Yb3 + moments and conduction electrons are weakly coupled. Despite the antiferromagnetic ordering below TN, YbNi4Cd exhibits a large frustration parameter | θp/TN|˜16 , where the magnetic Yb3 + ions occupy the tetrahedra on the fcc lattice.

The role of nano-contacts in electrical transport through a molecular wire

International Nuclear Information System (INIS)

Shokri, Ali A.; Mardaani, M.

2006-01-01

Theoretical studies on electrical transport in a nano-device which consisting of two semi-infinite cubic leads with finite cross-sections separated by a typical molecular wire (MW) are carried out by including the effect of single and multiple contacts. The calculations are based on the tight-binding model and Green's function method in the coherent regime. In order to calculate the effect of contact coupling on molecular wire transport, we derive a theoretical formula based on the nearest and next nearest neighbor coupling strengths between the MW and the surface atoms in the simple cubic leads. This approach can be generalized to other leads with different lattice structure. The results show small changes in the transport properties with changing next nearest neighbor coupling strength. Some asymmetry is noted in the strong multiple contact limit. Also, we observe that with enlarging the cross-section size of leads, the current density increases and then leads to the quantum unit of conductance. Hence, our derived formalism can be used for devices attached to macroscopic surfaces. The theoretical results obtained, can be a base for developments in designing nano-electronic devices

Electrical and thermal transport properties of Y bxCo4Sb12 filled skutterudites with ultrahigh carrier concentrations

Directory of Open Access Journals (Sweden)

Yulong Li

2015-11-01

Full Text Available For filled skutterudites, element Yb is one of the most common and important fillers. However, the optimal carrier concentration range in Y bxCo4Sb12 filled skutterudites has not been determined as a result of the low Yb filling fraction limit. In this study, a non-equilibrium fabrication process (MS-SPS process, consisting of a melt-spinning method and a spark plasma sintering technique, has been applied to prepare Y bxCo4Sb12 samples. The Yb filling fraction is successfully extended to 0.35, which provides the possibility to clarify the optimal carrier concentration range for Yb-filled skutterudites. High carrier concentrations, with a maximum of around 1 × 1021 cm−3, were achieved in the MS-SPS Y bxCo4Sb12 samples due to the significantly enhanced Yb filling fractions. The phase compositions, lattice parameters, electrical and thermal transport properties of the MS-SPS Y bxCo4Sb12 samples with high carrier concentrations were systematically investigated. An optimal carrier concentration range of around 5 ∼ 6 × 1020 cm−3, corresponding to the actual Yb filling fraction of around 0.21∼0.26, has been determined, which displays the highest thermoelectric performance in Y bxCo4Sb12 thermoelectric materials.

Study of electrical properties of polyvinylpyrrolidone/polyacrylamide ...

Indian Academy of Sciences (India)

https://www.ias.ac.in/article/fulltext/boms/037/02/0273-0279. Keywords. PVP; PAM; conductivity; activation energy; relaxation time; electric modulus. Abstract. Electrical properties of polyvinylpyrrolidone, polyacrylamide and their blend thin films have been investigated as a function of temperature and frequency. The films ...

Diazonium functionalized graphene: microstructure, electric, and magnetic properties.

Science.gov (United States)

Huang, Ping; Jing, Long; Zhu, Huarui; Gao, Xueyun

2013-01-15

The unique honeycomb lattice structure of graphene gives rise to its outstanding electronic properties such as ultrahigh carrier mobility, ballistic transport, and more. However, a crucial obstacle to its use in the electronics industry is its lack of an energy bandgap. A covalent chemistry strategy could overcome this problem, and would have the benefits of being highly controllable and stable in the ambient environment. One possible approach is aryl diazonium functionalization. In this Account, we investigate the micromolecular/lattice structure, electronic structure, and electron-transport properties of nitrophenyl-diazonium-functionalized graphene. We find that nitrophenyl groups mainly adopt random and inhomogeneous configurations on the graphene basal plane, and that their bonding with graphene carbon atoms leads to slight elongation of the graphene lattice spacing. By contrast, hydrogenated graphene has a compressed lattice. Low levels of functionalization suppressed the electric conductivity of the resulting functionalized graphene, while highly functionalized graphene showed the opposite effect. This difference arises from the competition between the charge transfer effect and the scattering enhancement effect introduced by nitrophenyl groups bonding with graphene carbon atoms. Detailed electron transport measurements revealed that the nitrophenyl diazonium functionalization locally breaks the symmetry of graphene lattice, which leads to an increase in the density of state near the Fermi level, thus increasing the carrier density. On the other hand, the bonded nitrophenyl groups act as scattering centers, lowering the mean free path of the charge carriers and suppressing the carrier mobility. In rare cases, we observed ordered configurations of nitrophenyl groups in local domains on graphene flakes due to fluctuations in the reaction processes. We describe one example of such a superlattice, with a lattice constant nearly twice of that of pristine graphene

Effects of electric-field-induced piezoelectric strain on the electronic transport properties of La0.9Ce0.1MnO3 thin films

International Nuclear Information System (INIS)

Zheng, R.K.; Dong, S.N.; Wu, Y.Q.; Zhu, Q.X.; Wang, Y.; Chan, H.L.W.; Li, X.M.; Luo, H.S.; Li, X.G.

2012-01-01

The authors constructed multiferroic structures by growing La 0.9 Ce 0.1 MnO 3 (LCEMO) thin films on piezoelectric 0.68Pb(Mg 1/3 Nb 2/3 )O 3 –0.32PbTiO 3 (PMN-PT) single-crystal substrates. Due to the efficient elastic coupling at the interface, the electric-field-induced piezoelectric strain in PMN-PT substrates is effectively transferred to LCEMO films and thus, leads to a decrease in the resistance and an increase in the magnetoresistance of the films. Particularly, it was found that the resistance-strain coefficient [(ΔR/R) film /(Δε zz ) film ] of the LCEMO film was considerably enhanced by the application of magnetic fields, demonstrating strong coupling between the lattice and the spin degrees of freedom. (ΔR/R) film /(Δε zz ) film at 122 K was enhanced by ∼ 28.8% by a magnetic field of 1.2 T. An analysis of the overall results demonstrates that the phase separation is crucial to understand strain-mediated modulation of electronic transport properties of manganite film/PMN-PT multiferroic structures. - Highlights: ► La 0.9 Ce 0.1 Mn O3 films were epitaxially grown on piezoelectric single crystals. ► Piezoelectric strain influences the electronic transport properties of films. ► Magnetic field enhances the piezoelectric strain effect. ► Phase separation is crucial to understand the piezoelectric strain effect.

Electrical transport properties of MoO{sub 3} thin films prepared by laser assisted evaporation

Energy Technology Data Exchange (ETDEWEB)

Lopez-Carreno, L.D.; Pardo, A.; Zuluaga, M.; Torres, J.; Alfonso, J.E. [Group of Materials with Technological Applications, GMAT, Physics Department, Universidad Nacional de Colombia, Bogota (Colombia); Cortes-Bracho, O.L. [Group of Materials with Technological Applications, GMAT, Physics Department, Universidad Nacional de Colombia, Bogota (Colombia); Electronic Engineering Department, Universidad Nacional de Colombia, Bogota (Colombia)

2007-07-01

In the present paper the growth of MoO{sub 3} thin films on common glass substrates are described. The films were prepared by evaporation of a MoO{sub 3} target with a CO{sub 2} laser (10.6 {mu}m), operating in the continuous wave mode. The effect of substrate temperature on the crystallographic structure and electrical properties of MoO{sub 3} thin films was studied. The chemical composition of the different species formed on the films surface was obtained by X-ray photoelectron spectroscopy (XPS) and the crystalline structure was studied with X-ray diffraction (XRD). The electrical conductivity of the films was determined using the standard four-points method. Conductivity of the films varied from de 10{sup -9} to 10{sup -5} ({omega}cm){sup -1} in the 300-600 K temperature range. Arrhenius-type plots for the electrical conductivity indicate the presence of at least two different conduction mechanisms. The I-V characteristic curve shows an ohmic behavior only in the 4.5-60 V range. Outside this interval the I-V curve has a behavior described by a power law. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Structural and transport properties of nanocrystalline MnFe/sub 2/O/sub 4/ synthesized by co-precipitation method

International Nuclear Information System (INIS)

Akhtar, M.J.; Younas, M.

2012-01-01

The nanocrystalline ferrites with spinel structures have been the focus of scientific investigation and received continuous interest in recent decades. The structural and electrical properties of these materials have become an important area of research and are attracting considerable interest due to broad range of applications. Spinel ferrites have been shown to exhibit interesting dielectric properties in the nanocrystalline form in comparison to the corresponding bulk materials. Structural and electrical properties of nanocrystalline MnFe/sub 2/O/sub 4/ were investigated. X-ray diffraction and X-ray absorption fine structure spectroscopy results showed that nanocrystalline MnFe/sub 2/O/sub 4/ had cubic symmetry with 80% inversion. shows the X-ray absorption near edge structure (XANES) spectra of MnFe/sub 2/O/sub 4/ and Zn/sub 1-x/Ni/sub x/Fe/sub 2/O/sub 4/, used as model compounds. The electrical transport properties were investigated by employing impedance spectroscopy. It was observed that the dielectric constant decreased with the increase in frequency. The effects of frequency on dielectric properties were more prominent in the low frequency region, where dielectric constant increased as temperature was increased. (Orig./A.B.)

Low temperature synthesis of graphene on arbitrary substrates and its transport properties

Science.gov (United States)

Zhao, Rong; Akhtar, Meysam; Alruqi, Adel; Jasinski, Jacek; Sumanasekera, Gamini; Department of Physics; Astronomy, University of Louisville Collaboration; Conn CenterRenewable Energy, University of Louisville Collaboration

Here we report the direct synthesis of uniform and vertically oriented graphene films on multiple substrates including glass, Si/SiO2, and copper foil by radio-frequency plasma enhanced chemical vapor deposition (PECVD) using methane as the carbon precursor at relatively low temperatures. Raman spectra of all the samples show characteristic Raman peaks of graphene. The temperature dependence of electrical transport properties such as 4-probe resistance, thermo electrical power and hall mobility were measured for graphene grown on glass substrates at varying temperature from 500 ° C to 700 ° C. The morphological and surface characteristics were also studied by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). This work demonstrates the potential of low temperature and transfer-free graphene growth for future graphene-based electronic applications.

The Predominance of Electric Transport in Synaptic Transmission

OpenAIRE

Hamid Reza Noori

2008-01-01

The quantitative description of the motion of neurotransmitters in the synaptic cleft appears to be one of the most difficult problems in the modeling of synapses. Here we show in contradiction to the common view, that this process is merely governed by electric transport than diffusion forces.

Comparison between the electrical properties of polyphenylacetylene and polyaminotriazole

Directory of Open Access Journals (Sweden)

M. Yahia Abed

2014-03-01

Full Text Available The electrical properties of a polymer containing aromatic rings were compared with those of polyheterocyclic compound. Each segment of the polyheterocyclic compound contains three nitrogen atoms. Both polymers were prepared at the laboratory. It was found that the specific electrical conductivity of polyphenylacetylene is higher than that of polyaminotriazole. Log ρ vs. 103/T was traced for both compounds, where ρ is the specific electrical resistivity and T is the absolute temperature. Complexes of each compound with KI were prepared. The electrical properties of these complexes were studied. The microstructure of both compounds was determined by FTIR spectroscopy.

Transport properties of the LiNi{sub 1-y}Co{sub y}O{sub 2} system

Energy Technology Data Exchange (ETDEWEB)

Molenda, J.; Wilk, P.; Marzec, J. [Department of Solid State Chemistry, Stanislaw Staszic University of Mining and Metallurgy, Al. A. Mickiewicza 30, 30-059 Cracow (Poland)

1999-04-15

In this paper results are presented concerning structure, electrical conductivity and thermoelectric power measurements of the LiNi{sub 1-y}Co{sub y}O{sub 2} system. It has been stated that holes are dominating carriers. It has been also found that cobalt worsens the transport properties of the LiNi{sub 1-y}Co{sub y}O{sub 2} system

Phase transition and electrical properties of strontium orthovanadate

International Nuclear Information System (INIS)

Pati, Biswajit; Choudhary, R.N.P.; Das, Piyush R.

2013-01-01

Highlights: •Highly crystallized Sr 3 V 2 O 8 ceramic has a structural and micro-structural stability. •The low values of ε r and tan δ make this material useful for microwave applications. •The material exhibits good ferroelectric properties suitable for memory devices. •The dielectric relaxation is of non Debye-type and ac conductivity obeys Jonscher power law. •The small value of dc activation energy suggests the conduction initiates with a small energy. -- Abstract: The current research work reports the study of phase transition and transport mechanism in lead-free strontium orthovanadate (Sr 3 V 2 O 8 ), prepared using a high-temperature solid-state reaction technique. Preliminary X-rays diffraction studies exhibit the formation of a single-phase compound in the trigonal crystal system. Study of microstructure of gold-coated pellet by scanning electron microscopy (SEM) shows well-defined and homogeneous grains in the morphology. Detailed studies of dielectric parameters (ε r and tan δ) of the compound as a function of temperature at some selected frequencies reveal their independence for a wide range of temperatures. An anomaly in relative permittivity (ε r ) suggests the existence of a ferroelectric–paraelectric phase transition of diffuse-type in the material that confirms through the detailed studies of its electric polarization. Detailed studies of impedance and related parameters exhibit that the electrical properties of the material are strongly dependent on temperature, and bear a good correlation with its microstructure (i.e., bulk, grain boundary, etc.). The decrease in value of bulk resistance on increasing temperature suggests the negative temperature co-efficient of resistance (NTCR) behavior of the material. Studies of electric modulus indicate the presence of hopping conduction mechanism in the system with non-exponential type of conductivity relaxation. The nature of variation of dc conductivity with temperature confirms the

Electrical and electrochemical properties of niobium disulphide

Energy Technology Data Exchange (ETDEWEB)

Molenda, J.; Bak, T.; Marzec, J. [Academy of Min. and Metall., Cracow (Poland). Dept. of Chem. of Solids

1996-07-16

The electrical conductivity and thermoelectric power measurements of NbS{sub 2} pure and electrochemically doped with lithium, Li{sub x}NbS{sub 2}, were done as a function of temperature (77 to 300 K). The high absolute values of conductivity and their dependence on temperature together with low absolute values of thermoelectric power and their linear increase with temperature indicate metallic properties of niobium disulphide. In case of Li{sub x}NbS{sub 2} the obtained values of electrical conductivity are significantly lower as compared with the starting NbS{sub 2}. The temperature dependence of the thermo-electric power of intercalated niobium disulphide also indicates that metallic properties get worse as the concentration of lithium increases. The modification of the electronic structure of NbS{sub 2} due to lithium intercalation was proposed. The character of the discharge curves in the electrochemical Li/Li{sup +}/Li{sub x}NbS{sub 2} systems was correlated with the electronic properties of niobium disulphide. (orig.) 11 refs.

Electric and magnetic fields effects on the transport properties of La{sub 0.5}Ca{sub 0.5}MnO{sub 3} thin films

Energy Technology Data Exchange (ETDEWEB)

Villafuerte, M. E-mail: mvillafeurte@herrera.unt.edu.ar; Duhalde, S. E-mail: sduhald@fi.uba.ar; Rubi, D.; Bridoux, G.; Heluani, S.; Sirena, M.; Steren, L

2004-05-01

The insulator to metal transition in manganites can be drastically influenced by internal factors, such as chemical composition, or under a variety of external perturbations, like magnetic or electric fields. In this work, the electrical resistance of La{sub 0.5}Ca{sub 0.5}MnO{sub 3} thin films was investigated using different constant voltages. At low temperature the conductivity of the films is non-Ohmic and moderate electric fields results in resistivity switching to metastable states. Comparisons between the influence of magnetic and electric fields on transport measurements are reported.

Hopping transport and electrical conductivity in one-dimensional systems with off-diagonal disorder

International Nuclear Information System (INIS)

Ma Songshan; Xu Hui; Li Yanfeng; Song Zhaoquan

2007-01-01

In this paper, we present a model to describe hopping transport and electrical conductivity of one-dimensional systems with off-diagonal disorder, in which electrons are transported via hopping between localized states. We find that off-diagonal disorder leads to delocalization and drastically enhances the electrical conductivity of systems. The model also quantitatively explains the temperature and electrical field dependence of the conductivity in one-dimensional systems with off-diagonal disorder. In addition, we also show the dependence of the conductivity on the strength of off-diagonal disorder

Enhanced electrical transport and thermoelectric properties in Ni doped Cu3SbSe4

Science.gov (United States)

Kumar, Aparabal; Dhama, P.; Das, Anish; Sarkar, Kalyan Jyoti; Banerji, P.

2018-05-01

In this study, we report the enhanced thermoelectric performance of Cu3SbSe4 by Ni doping at Cu site. Cu3-xNixSbSe4 (x = 0, 0.01, 0.03, 0.05) were prepared by melt growth, ball milling followed by spark plasma sintering. Structural characterization, phase analysis and surface morphology were carried out using X-ray diffraction, field emission scanning electron microscopy and energy dispersive X-ray spectroscopy. Electrical and thermal properties of all the samples were investigated in the temperature range 300 - 650 K. Decrease in electrical resistivity with Ni doping due to increase in carrier concentration with enhanced Seebeck coefficient via increase in density of state near the Fermi level gives a remarkably high power factor. At the same time, thermal conductivity was found to decrease due to increased carrier-phonon scattering and acoustic phonon scattering. Consequently, a remarkable enhancement in the thermoelectric figure of merit (ZT˜ 0.65) of Cu3-xNixSbSe4 was achieved for x = 0.01 sample. Thus, Ni doping is an effective approach to improve the efficiency of Cu3SbSe4.

Electrical and optoelectronic properties of gallium nitride

International Nuclear Information System (INIS)

Flannery, Lorraine Barbara

2002-01-01

This thesis describes novel research carried out on two related topics, the electrical properties of n and p-type GaN and the use of GaN in the fabrication of UV photodetectors. The electrical properties of GaN were assessed mainly by Hall effect measurements, which play a crucial role in the determination of the concentration of shallow electrically active impurities and defects. Most of the Hall effect measurements were carried out on Si and unintentionally doped GaN layers grown on sapphire substrates using a Varian Modular Gen II MBE machine equipped with an Oxford Applied Research CARS25 RF or HD25 RF nitrogen source to supply the active nitrogen. It was necessary to consider parallel conduction in two channels to interpret the temperature dependent Hall effect characteristics of the highest purity layers. Parallel conduction was found to influence the transport properties of these layers even at room temperature and give rise to an increased compensation ratio. The impurity band was found to be located at 23 ± 7 meV below the conduction band in layers containing impurity densities less than 3.8 x 10 18 cm -3 but was found to broaden with increasing impurity content, reducing the activation energy to 5 ± 3 meV in layers containing impurity densities greater than ∼4.5 x 10 18 cm -3 . Doping studies were conducted on Mg doped GaN layers grown on sapphire substrates using the MBE and MOVPE growth techniques. The effect of the growth parameters on Mg incorporation was determined using SIMS and Hall effect measurements for the MBE samples sets. P-type conductivity was successfully demonstrated in Mg doped layers grown under nitrogen rich conditions with layer thickness greater than 0.9 μm using the CARS25 RF source. The highest hole density, p H and mobility, μ H of 9.6 x 10 17 cm -3 and 5.4 cm 2 V -1 s -1 respectively were recorded in the thickest layer grown (1.56 μm). P-type doping studies were also carried out on Mg doped GaN layers grown on GaAs (111)B

Thermal transport properties of niobium and some niobium-based alloys from 80 to 1600 K

Energy Technology Data Exchange (ETDEWEB)

Moore, J P; Graves, R S; Williams, R K [Oak Ridge National Lab., TN (USA)

1980-01-01

The electric resistivity, rho, and Seebeck coefficient, S, of 99.8 at% niobium, and Nb-4.8 at% W, Nb-5 at% Mo, Nb-10 at% Mo, and Nb-2.4 at% Mo-2.4 at% Zr alloys were measured from 80 to 1600 K, and the thermal conductivity, lambda, of the niobium and the Nb-5 at% W alloy was measured from 80 to 1300 K. A technique is described for measuring rho and S of a specimen during radial-heat-flow measurements of lambda. The transport property results, which had uncertainties of +-0.4% for rho and +-1.4% for lambda, showed the influence of tungsten and molybdenum solutes on the transport properties of niobium and were used to obtain the electronic Lorenz function of pure niobium, which was found to approach the Sommerfeld value at high temperatures.

Transport modelling including radial electric field and plasma rotation

International Nuclear Information System (INIS)

Fukuyama, A.; Fuji, Y.; Itoh, S.-I.

1994-01-01

Using a simple turbulent transport model with a constant diffusion coefficient and a fixed temperature profile, the density profile in a steady state and the transient behaviour during the co and counter neutral beam injection are studied. More consistent analysis has been initiated with a turbulent transport model based on the current diffusive high-n ballooning mode. The enhancement of the radial electric field due to ion orbit losses and the reduction of the transport due to the poloidal rotation shear are demonstrated. The preliminary calculation indicates a sensitive temperature dependence of the density profile. (author)

Electrical and Electrochemical Properties of Conducting Polymers

Directory of Open Access Journals (Sweden)

Thanh-Hai Le

2017-04-01

Full Text Available Conducting polymers (CPs have received much attention in both fundamental and practical studies because they have electrical and electrochemical properties similar to those of both traditional semiconductors and metals. CPs possess excellent characteristics such as mild synthesis and processing conditions, chemical and structural diversity, tunable conductivity, and structural flexibility. Advances in nanotechnology have allowed the fabrication of versatile CP nanomaterials with improved performance for various applications including electronics, optoelectronics, sensors, and energy devices. The aim of this review is to explore the conductivity mechanisms and electrical and electrochemical properties of CPs and to discuss the factors that significantly affect these properties. The size and morphology of the materials are also discussed as key parameters that affect their major properties. Finally, the latest trends in research on electrochemical capacitors and sensors are introduced through an in-depth discussion of the most remarkable studies reported since 2003.

Electrical and thermal properties of graphite/polyaniline composites

Energy Technology Data Exchange (ETDEWEB)

Bourdo, Shawn E., E-mail: sxbourdo@ualr.edu [Center for Integrative Nanotechnology Sciences, University of Arkansas at Little Rock, 2801 South University Avenue, Little Rock, AR 72204 (United States); Warford, Brock A.; Viswanathan, Tito [Department of Chemistry, University of Arkansas at Little Rock, 2801 South University Avenue, Little Rock, AR 72204 (United States)

2012-12-15

A composite of a carbon allotrope (graphite) and an inherently conducting polymer, polyaniline (PANI), has been prepared that exhibits an electrical conductivity greater than either of the two components. An almost 2-fold increase in the bulk conductivity occurs when only a small mass fraction of polyaniline exists in the composite (91% graphite/ 9% polyaniline, by mass). This increase in dc electrical conductivity is curious since in most cases a composite material will exhibit a conductivity somewhere between the two individual components, unless a modification to the electronic nature of the material occurs. In order to elucidate the fundamental electrical properties of the composite we have performed variable temperature conductivity measurements to better understand the nature of conduction in these materials. The results from these studies suggest a change in the mechanism of conduction as the amount of polyaniline is increased in the composite. Along with superior electrical properties, the composites exhibit an increase in thermal stability as compared to the graphite. - Graphical abstract: (Left) Room temperature electrical conductivity of G-PANI composites at different mass ratios. (Right) Electrical conductivity of G-PANI composites at temperatures from 5 K to 300 K. Highlights: Black-Right-Pointing-Pointer Composites of graphite and polyaniline have been synthesized with unique electrical and thermal properties. Black-Right-Pointing-Pointer Certain G-PANI composites are more conductive and more thermally stable than graphite alone. Black-Right-Pointing-Pointer G-PANI composites exhibit a larger conductivity ratio with respect to temperature than graphite alone.

Bulk-Like Electrical Properties Induced by Contact-Limited Charge Transport in Organic Diodes: Revised Space Charge Limited Current

KAUST Repository

Xu, Guangwei; Gao, Nan; Lu, Congyan; Wang, Wei; Ji, Zhuoyu; Bi, Chong; Han, Zhiheng; Lu, Nianduan; Yang, Guanhua; Li, Yuan; Liu, Qi; Li, Ling; Liu, Ming

2018-01-01

, the charge transport properties of organic diodes are usually characterized by probing the current–voltage (I–V) curves of the devices. However, to unveil the landscape of the underlying potential/charge distribution, which essentially determines the I

Modeling light-duty plug-in electric vehicles for national energy and transportation planning

International Nuclear Information System (INIS)

Wu, Di; Aliprantis, Dionysios C.

2013-01-01

This paper sets forth a family of models of light-duty plug-in electric vehicle (PEV) fleets, appropriate for conducting long-term national-level planning studies of the energy and transportation sectors in an integrated manner. Using one of the proposed models, three case studies on the evolution of the U.S. energy and transportation infrastructures are performed, where portfolios of optimum investments over a 40-year horizon are identified, and interdependencies between the two sectors are highlighted. The results indicate that with a gradual but aggressive introduction of PEVs coupled with investments in renewable energy, the total cost from the energy and transportation systems can be reduced by 5%, and that overall emissions from electricity generation and light-duty vehicle (LDV) tailpipes can be reduced by 10% over the 40-year horizon. The annual gasoline consumption from LDVs can be reduced by 66% by the end of the planning horizon, but an additional 800 TWh of annual electricity demand will be introduced. In addition, various scenarios of greenhouse gas (GHG) emissions reductions are investigated. It is found that GHG emissions can be significantly reduced with only a marginal cost increment, by shifting electricity generation from coal to renewable sources. - Highlights: • We model plug-in electric vehicles (PEVs) for long-term national planning studies. • Realistic travel patterns are used to estimate the vehicles' energy consumption. • National energy and transportation system interdependencies are considered. • Case studies illustrate optimum investments in energy and transportation sectors. • PEVs synergistically with renewable energy can aggressively reduce GHG emissions

Structural and electrical properties of ZnO/Zn0.85Mg0.15O thin film prepared by pulsed laser deposition

Science.gov (United States)

Yang, Jing-Jing; Wang, Gang; Du, Wen-Han; Xiong, Chao

2017-07-01

The electrical transport properties are the key factors to determine the performance of ZnO-based quantum effect device. ZnMgO is a typical material to regulate the band of ZnO. In order to investigate the electrical properties of the interface of ZnO/Zn0.85Mg0.15O films, three kinds of ZnO/Zn0.85Mg0.15O films have been fabricated with different thickness. After comparing the structural and electrical properties of the samples, we found that the independent Zn0.85Mg0.15O hexagonal wurtzite structure (002) peak can be detected in XRD spectra. Hall-effect test data confirmed that the two-dimensional electron gas (2DEG) became lower because of the decrease of thickness of Zn0.85Mg0.15O films, increase of impurity scattering and lattice structure distortion caused by the increase of Mg content.

Effects of lithium doping on microstructure, electrical properties, and chemical bonds of sol-gel derived NKN thin films

International Nuclear Information System (INIS)

Lin, Chun-Cheng; Chen, Chan-Ching; Weng, Chung-Ming; Chu, Sheng-Yuan; Hong, Cheng-Shong; Tsai, Cheng-Che

2015-01-01

Highly (100/110) oriented lead-free Li x (Na 0.5 K 0.5 ) 1−x NbO 3 (LNKN, x = 0, 0.02, 0.04, and 0.06) thin films are fabricated on Pt/Ti/SiO 2 /Si substrates via a sol-gel processing method. The lithium (Li) dopants modify the microstructure and chemical bonds of the LNKN films, and therefore improve their electrical properties. The optimal values of the remnant polarization (P r  = 14.3 μC/cm 2 ), piezoelectric coefficient (d 33  = 48.1 pm/V), and leakage current (<10 −5 A/cm 2 ) are obtained for a lithium addition of x = 0.04 (i.e., 4 at. %). The observation results suggest that the superior electrical properties are the result of an improved crystallization, a larger grain size, and a smoother surface morphology. It is shown that the ion transport mechanism is dominated by an Ohmic behavior under low electric fields and the Poole-Frenkel emission effect under high electric fields

2013 International Conference on Electrical and Information Technologies for Rail Transportation

CERN Document Server

Liu, Zhigang; Qin, Yong; Zhao, Minghua; Diao, Lijun

2014-01-01

Proceedings of the 2013 International Conference on Electrical and Information Technologies for Rail Transportation (EITRT2013) collects the latest research in this field, including a wealth of state-of-the-art research theories and applications in intelligent computing, information processing, communication technology, automatic control, etc. The objective of the proceedings is to provide a major interdisciplinary forum for researchers, engineers, academics and industrial professionals to present the most innovative research on and developments in the field of rail transportation electrical and information technologies. Contributing authors from academia, industry and the government also offer inside views of new, interdisciplinary solutions.

Transport properties of molecular junctions

CERN Document Server

Zimbovskaya, Natalya A

2013-01-01

A comprehensive overview of the physical mechanisms that control electron transport and the characteristics of metal-molecule-metal (MMM) junctions is presented. As far as possible, methods and formalisms presented elsewhere to analyze electron transport through molecules are avoided. This title introduces basic concepts—a description of the electron transport through molecular junctions—and briefly describes relevant experimental methods. Theoretical methods commonly used to analyze the electron transport through molecules are presented. Various effects that manifest in the electron transport through MMMs, as well as the basics of density-functional theory and its applications to electronic structure calculations in molecules are presented. Nanoelectronic applications of molecular junctions and similar systems are discussed as well. Molecular electronics is a diverse and rapidly growing field. Transport Properties of Molecular Junctions presents an up-to-date survey of the field suitable for researchers ...

Electrifying Australian transport: Hybrid life cycle analysis of a transition to electric light-duty vehicles and renewable electricity

International Nuclear Information System (INIS)

Wolfram, Paul; Wiedmann, Thomas

2017-01-01

Highlights: •This research assesses life-cycle carbon impacts of different powertrains. •We illustrate a transition to low-carbon vehicles in a hybrid IO-LCA model. •Different electricity and transport scenarios are integrated in the model. •With Australia’s current grid-mix, electric vehicles offer no mitigation potential. •Using renewable energy, electric vehicle carbon footprints can be cut by 66%. -- Abstract: Recent life cycle assessments confirmed the greenhouse gas emission reduction potential of renewable electricity and electric vehicle technologies. However, each technology is usually assessed separately and not within a consistent macro-economic, multi-sectoral framework. Here we present a multi-regional input-output based hybrid approach with integrated scenarios to facilitate the carbon footprint assessment of all direct and indirect effects of a transition to low-emission transportation and electricity generation technologies in Australia. The work takes into account on-road energy consumption values that are more realistic than official drive-cycle energy consumption figures used in previous work. Accounting for these factors as well as for Australia’s grid electricity, which heavily relies on coal power, electric vehicles are found to have a higher carbon footprint than conventional vehicles, whereas hybrid electric vehicles have the lowest. This means that – from a carbon footprint perspective – powertrain electrification is beneficial only to a certain degree at the current stage. This situation can be changed by increasing shares of renewable electricity in the grid. In our best-case scenario, where renewable energy accounts for 96% of the electricity mix in 2050, electric vehicle carbon footprints can be cut by 66% by 2050 relative to 2009. In the business-as-usual scenario (36% renewable electricity share by 2050), electric vehicles can reach a 56% reduction if fossil fuel power plants significantly increase their efficiencies

Modulation of electrical properties in Cu/n-type InP Schottky junctions using oxygen plasma treatment

International Nuclear Information System (INIS)

Kim, Hogyoung; Jung, Chan Yeong; Hyun Kim, Se; Cho, Yunae; Kim, Dong-Wook

2015-01-01

Using current–voltage (I–V) measurements, we investigated the effect of oxygen plasma treatment on the temperature-dependent electrical properties of Cu/n-type indium phosphide (InP) Schottky contacts at temperatures in the range 100–300 K. Changes in the electrical parameters were evident below 180 K for the low-plasma-power sample (100 W), which is indicative of the presence of a wider distribution of regions of low barrier height. Modified Richardson plots were used to obtain Richardson constants, which were similar to the theoretical value of 9.4 A cm −2 K −2 for n-type InP. This suggests that, for all the samples, a thermionic emission model including a spatially inhomogeneous Schottky barrier can be used to describe the charge transport phenomena at the metal/semiconductor interface. The voltage dependence of the reverse-bias current revealed that Schottky emission was dominant for the untreated and high-plasma-power (250 W) samples. For the low-plasma-power sample, Poole–Frenkel emission was dominant at low voltages, whereas Schottky emission dominated at higher voltages. Defect states and nonuniformity of the interfacial layer appear to be significant in the reverse-bias charge transport properties of the low-plasma-power sample. (paper)

Electrical/thermal transport and electronic structure of the binary cobalt pnictides CoPn2 (Pn = As and Sb

Directory of Open Access Journals (Sweden)

Yosuke Goto

2015-06-01

Full Text Available We demonstrate the electrical and thermal transport properties of polycrystalline CoPn2 (Pn = As and Sb between 300 and 900 K. CoAs2 shows semiconducting electrical transport up to 900 K, while CoSb2 exhibits degenerate conduction. Sign inversion of the Seebeck coefficient is observed at ∼310 and ∼400 K for CoAs2 and CoSb2, respectively. Thermal conductivity at 300 K is 11.7 Wm−1K−1 for CoAs2 and 9.4 Wm−1K−1 for CoSb2. The thermoelectric power factor of CoAs2 is ∼10 μWcm−1K−2, although the dimensionless figure of merit is limited to ∼0.1 due to relatively high thermal conductivity. Using electronic structure calculations, the band gap value is calculated to be 0.55 eV for CoAs2 and 0.26 eV for CoSb2.

Electricity resonance-induced fast transport of water through nanochannels.

Science.gov (United States)

Kou, Jianlong; Lu, Hangjun; Wu, Fengmin; Fan, Jintu; Yao, Jun

2014-09-10

We performed molecular dynamics simulations to study water permeation through a single-walled carbon nanotube with electrical interference. It was found that the water net flux across the nanochannel is greatly affected by the external electrical interference, with the maximal net flux occurred at an electrical interference frequency of 16670 GHz being about nine times as high as the net flux at the low or high frequency range of (80,000 GHz). The above phenomena can be attributed to the breakage of hydrogen bonds as the electrical interference frequency approaches to the inherent resonant frequency of hydrogen bonds. The new mechanism of regulating water flux across nanochannels revealed in this study provides an insight into the water transportation through biological water channels and has tremendous potential in the design of high-flux nanofluidic systems.

Long term energy and emission implications of a global shift to electricity-based public rail transportation system

International Nuclear Information System (INIS)

Chaturvedi, Vaibhav; Kim, Son H.

2015-01-01

With high reliance on light-duty vehicles in the present, the future of global transportation system is also geared towards private modes, which has significant energy and emission implications. Public transportation has been argued as an alternative strategy for meeting the rising transportation demands of the growing world, especially the poor, in a sustainable and energy efficient way. The present study analyzes an important yet under-researched question – what are the long-term energy and emission implications of an electric rail based passenger transportation system for meeting both long and short distance passenter transportation needs? We analyze a suite of electric rail share scenarios with and without climate policy. In the reference scenario, the transportation system will evolve towards dominance of fossil based light-duty vehicles. We find that an electric rail policy is more successful than an economy wide climate policy in reducing transport sector energy demand and emissions. Economy wide emissions however can only be reduced through a broader climate policy, the cost of which can be reduced by hundreds of billions of dollars across the century when implemented in combination with the transport sector focused electric rail policy. Moreover, higher share of electric rail enhances energy security for oil importing nations and reduces vehicular congestion and road infrastructure requirement as well. -- Highlights: •Economy wide carbon price policy will have little impact on transportation emissions. •Focused energy and emission mitigation policies required for transportation sector. •Large global shift towards electric rail based public transport is one possible option. •Transport sector focused policy will have marginal impact on total global emissions. •A combined transport sector and economy wide policy can reduce costs significantly

Transport properties of alumina nanofluids

International Nuclear Information System (INIS)

Wong, Kau-Fui Vincent; Kurma, Tarun

2008-01-01

Recent studies have showed that nanofluids have significantly greater thermal conductivity compared to their base fluids. Large surface area to volume ratio and certain effects of Brownian motion of nanoparticles are believed to be the main factors for the significant increase in the thermal conductivity of nanofluids. In this paper all three transport properties, namely thermal conductivity, electrical conductivity and viscosity, were studied for alumina nanofluid (aluminum oxide nanoparticles in water). Experiments were performed both as a function of volumetric concentration (3-8%) and temperature (2-50 deg. C). Alumina nanoparticles with a mean diameter of 36 nm were dispersed in water. The effect of particle size was not studied. The transient hot wire method as described by Nagaska and Nagashima for electrically conducting fluids was used to test the thermal conductivity. In this work, an insulated platinum wire of 0.003 inch diameter was used. Initial calibration was performed using de-ionized water and the resulting data was within 2.5% of standard thermal conductivity values for water. The thermal conductivity of alumina nanofluid increased with both increase in temperature and concentration. A maximum thermal conductivity of 0.7351 W m -1 K -1 was recorded for an 8.47% volume concentration of alumina nanoparticles at 46.6 deg. C. The effective thermal conductivity at this concentration and temperature was observed to be 1.1501, which translates to an increase in thermal conductivity by 22% when compared to water at room temperature. Alumina being a good conductor of electricity, alumina nanofluid displays an increasing trend in electrical conductivity as volumetric concentration increases. A microprocessor-based conductivity/TDS meter was used to perform the electrical conductivity experiments. After carefully calibrating the conductivity meter's glass probe with platinum tip, using a standard potassium chloride solution, readings were taken at various

Magnetocaloric effect and transport properties of Gd5Ge2(Si1-x Sn x )2 (x=0.23 and 0.40) compounds

International Nuclear Information System (INIS)

Campoy, J.C.P.; Plaza, E.J.R.; Nascimento, F.C.; Coelho, A.A.; Pereira, M.C.; Fabris, J.D.; Raposo, M.T.; Cardoso, L.P.; Persiano, A.I.C.; Gama, S.

2007-01-01

We report a study about the structural properties of polycrystalline samples of nominal composition Gd 5 Ge 2 (Si 1- x Sn x ) 2 (x=0.23, 0.40) that closely influence their physical behavior particularly related to electric resistivity and magnetocaloric (MCE) effect. The samples were characterized by X-ray diffraction (XRD) using the Rietveld refinement method, metallographic analyses, 119 Sn Moessbauer spectroscopy, DC magnetization and electrical transport measurements. It was identified a Gd 5 Si 2 Ge 2 -monoclinic phase for x=0.23 and a Sm 5 Sn 4 -orthorhombic phase (type II) for x=0.40, both with two non-equivalent crystallographic sites for the Sn ions. We were able to infer on the role of tin on the magnetic and transport properties in these compounds

Electric vehicles and renewable energy in the transport sector - energy system consequences. Main focus: Battery electric vehicles and hydrogen based fuel cell vehicles

Energy Technology Data Exchange (ETDEWEB)

Nielsen, L.H.; Joergensen, K.

2000-04-01

The aim of the project is to analyse energy, environmental and economic aspects of integrating electric vehicles in the future Danish energy system. Consequences of large-scale utilisation of electric vehicles are analysed. The aim is furthermore to illustrate the potential synergistic interplay between the utilisation of electric vehicles and large-scale utilisation of fluctuating renewable energy resources, such as wind power. Economic aspects for electric vehicles interacting with a liberalised electricity market are analysed. The project focuses on battery electric vehicles and fuel cell vehicles based on hydrogen. Based on assumptions on the future technical development for battery electric vehicles, fuel cell vehicles on hydrogen, and for the conventional internal combustion engine vehicles, scenarios are set up to reflect expected options for the long-term development of road transport vehicles. Focus is put on the Danish fleet of passenger cars and delivery vans. The scenario analysis includes assumptions on market potential developments and market penetration for the alternative vehicles. Vehicle replacement rates in the Danish transport fleet and the size of fleet development are based on data from The Danish Road Directorate. The electricity supply system development assumed is based on the Danish energy plan, Energy 21, The Plan scenario. The time horizon of the analysis is year 2030. Results from the scenario analysis include the time scales involved for the potential transition towards electricity based vehicles, the fleet composition development, the associated developments in transport fuel consumption and fuel substitution, and the potential CO{sub 2}-emission reduction achievable in the overall transport and power supply system. Detailed model simulations, on an hourly basis, have furthermore been carried out for year 2005 that address potential electricity purchase options for electric vehicles in the context of a liberalised electricity market

Electric vehicles and renewable energy in the transport sector - energy system consequences. Main focus: Battery electric vehicles and hydrogen based fuel cell vehicles

International Nuclear Information System (INIS)

Nielsen, L.H.; Joergensen, K.

2000-04-01

The aim of the project is to analyse energy, environmental and economic aspects of integrating electric vehicles in the future Danish energy system. Consequences of large-scale utilisation of electric vehicles are analysed. The aim is furthermore to illustrate the potential synergistic interplay between the utilisation of electric vehicles and large-scale utilisation of fluctuating renewable energy resources, such as wind power. Economic aspects for electric vehicles interacting with a liberalised electricity market are analysed. The project focuses on battery electric vehicles and fuel cell vehicles based on hydrogen. Based on assumptions on the future technical development for battery electric vehicles, fuel cell vehicles on hydrogen, and for the conventional internal combustion engine vehicles, scenarios are set up to reflect expected options for the long-term development of road transport vehicles. Focus is put on the Danish fleet of passenger cars and delivery vans. The scenario analysis includes assumptions on market potential developments and market penetration for the alternative vehicles. Vehicle replacement rates in the Danish transport fleet and the size of fleet development are based on data from The Danish Road Directorate. The electricity supply system development assumed is based on the Danish energy plan, Energy 21, The Plan scenario. The time horizon of the analysis is year 2030. Results from the scenario analysis include the time scales involved for the potential transition towards electricity based vehicles, the fleet composition development, the associated developments in transport fuel consumption and fuel substitution, and the potential CO 2 -emission reduction achievable in the overall transport and power supply system. Detailed model simulations, on an hourly basis, have furthermore been carried out for year 2005 that address potential electricity purchase options for electric vehicles in the context of a liberalised electricity market. The

Electric current induced forward and anomalous backward mass transport

International Nuclear Information System (INIS)

Somaiah, Nalla; Sharma, Deepak; Kumar, Praveen

2016-01-01

Multilayered test samples were fabricated in form of standard Blech structure, where W was used as the interlayer between SiO 2 substrate and Cu film. Electromigration test was performed at 250 °C by passing an electric current with a nominal density of 3.9  ×  10 10 A m −2 . In addition to the regular electromigration induced mass transport ensuing from the cathode towards the anode, we also observed anomalous mass transport from the anode to the cathode, depleting Cu from the anode as well. We propose an electromigration-thermomigration coupling based reasoning to explain the observed mass transport. (letter)

Hybrid Electric Propulsion Technologies for Commercial Transports

Science.gov (United States)

Bowman, Cheryl; Jansen, Ralph; Jankovsky, Amy

2016-01-01

NASA Aeronautics Research Mission Directorate has set strategic research thrusts to address the major drivers of aviation such as growth in demand for high-speed mobility, addressing global climate and capitalizing in the convergence of technological advances. Transitioning aviation to low carbon propulsion is one of the key strategic research thrust and drives the search for alternative and greener propulsion system for advanced aircraft configurations. This work requires multidisciplinary skills coming from multiple entities. The Hybrid Gas-Electric Subproject in the Advanced Air Transportation Project is energizing the transport class landscape by accepting the technical challenge of identifying and validating a transport class aircraft with net benefit from hybrid propulsion. This highly integrated aircraft of the future will only happen if airframe expertise from NASA Langley, modeling and simulation expertise from NASA Ames, propulsion expertise from NASA Glenn, and the flight research capabilities from NASA Armstrong are brought together to leverage the rich capabilities of U.S. Industry and Academia.

Electrical transport and thermochromic properties of polyaniline/chitosan/Co3O4 ternary nano composite

Science.gov (United States)

V, Mini; Kamath, Archana; S, Raghu; Chapi, Sharanappa; H, Devendrappa

2015-06-01

A new Polyaniline/ chitosan/ Co3O4 (CPAESCO) ternary nanocomposite is prepared by in situ oxidation polymerization of aniline in the presence of (NH4)2S2O8, chitosan and Co3O4. The Structural, Thermal, Optical and Electrical features of Polyaniline (PANI), Polyaniline/ chitosan (CPANI) and CPAESCO were analyzed using FT-IR, TGA, UV-vis analysis and Impedance spectroscopy by varying temperature. The results show that the introduction of the Co3O4 nanoparticles into CPANI matrix enhanced its properties. Mott's parameters show 3D -VRH Type conduction in it.

Probing exotic magnetic phases and electrical transport in Cr-rich γ-NiFeCr alloys

Energy Technology Data Exchange (ETDEWEB)

Pal, Pampa [S. N. Bose National Centre for Basic Sciences, Block JD, Sector III, Salt Lake, Kolkata 700098 (India); Majumdar, A.K., E-mail: akm@bose.res.in [S. N. Bose National Centre for Basic Sciences, Block JD, Sector III, Salt Lake, Kolkata 700098 (India); Ramakrishna Mission Vivekananda University, PO Belur Math, Howrah 711202 (India); Nigam, A.K. [Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400005 (India)

2015-05-01

We have identified ferromagnetic, antiferromagnetic, and re-entrant spin-glass-like phases in Cr-rich γ-NiFeCr alloys and studied their critical magnetic behavior. Their electrical resistivity exhibits distinct minima between 10 and 24 K with ρ∞−√T due to electron–electron interaction effects. Electron–phonon and electron–magnon contributions to ρ are isolated. The magnetoresistance shows hysteresis effects, a signature of spin-glass-like phases and a sign reversal with change of magnetic states. We have also observed that the nature of magnetic states strongly depends on the concentration of Fe and Cr. In this system, even a small amount of Fe enhances ferromagnetism a lot while addition of a little bit of Cr suppresses ferromagnetism and takes the system to the antiferromagnetic regime. The correlation between the magnetic and the electrical properties are more meaningful here since both studies were done on the same set of samples which have rather high melting points. - Highlights: • Identified ferro, antiferro, and re-entrant spin-glass phases in Ni–Fe–Cr alloys. • Resistivity ρ~−√T shows minima from 10–24 K due to electron–electron interaction. • Electron–phonon and electron–magnon contributions to ρ are isolated. • Magneto-transport measurements strengthened the magnetic phases identified. • Correlation in magnetic/electrical properties more meaningful if same samples used.

The on-line electric vehicle wireless electric ground transportation systems

CERN Document Server

Cho, Dong

2017-01-01

This book details the design and technology of the on-line electric vehicle (OLEV) system and its enabling wireless power-transfer technology, the “shaped magnetic field in resonance” (SMFIR). The text shows how OLEV systems can achieve their three linked important goals: reduction of CO2 produced by ground transportation; improved energy efficiency of ground transportation; and contribution to the amelioration or prevention of climate change and global warming. SMFIR provides power to the OLEV by wireless transmission from underground cables using an alternating magnetic field and the reader learns how this is done. This cable network will in future be part of any local smart grid for energy supply and use thereby exploiting local and renewable energy generation to further its aims. In addition to the technical details involved with design and realization of a fleet of vehicles combined with extensive subsurface charging infrastructure, practical issues such as those involved with pedestrian safety are c...

Textured Na x CoO2 Ceramics Sintered from Hydrothermal Platelet Nanocrystals: Growth Mechanism and Transport Properties

Science.gov (United States)

Zhang, Wei; Liu, Pengcheng; Wang, Yifeng; Zhu, Kongjun; Tai, Guoan; Liu, Jinsong; Wang, Jing; Yan, Kang; Zhang, Jianhui

2018-05-01

Nanostructuring is an effective approach to improve thermoelectric (TE) performance, which is caused by the interface and quantum effects on electron and phonon transport. For a typical layered structure such as sodium cobalt (NCO), a highly textured ceramic with nanostructure is beneficial for the carrier transport properties due to the strong anisotropy. In this paper, we established a textured NCO ceramic with highly oriented single crystals in nanoscale. The Na0.6CoO2 platelet crystals were prepared by a one-step hydrothermal method. The growth mechanism was revealed to involve dissolution-recrystallization and exchange reactions. NCO TE ceramics fabricated by a press-aided spark plasma sintering method showed a high degree of texturing, with the platelet crystals basically lying along the in-plane direction perpendicular to the press direction. TE properties of the textured NCO ceramics showed a strong anisotropic behavior. The in-plane electrical conductivity was considerably larger than the out-of-plane data because of fewer grain boundaries and interfaces that existed in the in-plane direction. Moreover, the in-plane Seebeck coefficient was higher because of the anisotropic electronic nature of NCO. Although the in-plane thermal conductivity was high, a prior ZT value was enabled for these NCO ceramics along this direction because of the dominant electrical transport. This finding provides a new approach to prepare highly oriented ceramics.

DC conductivity of twisted bilayer graphene: Angle-dependent transport properties and effects of disorder

Science.gov (United States)

Andelković, M.; Covaci, L.; Peeters, F. M.

2018-03-01

The in-plane dc conductivity of twisted bilayer graphene is calculated using an expansion of the real-space Kubo-Bastin conductivity in terms of Chebyshev polynomials. We investigate within a tight-binding approach the transport properties as a function of rotation angle, applied perpendicular electric field, and vacancy disorder. We find that for high-angle twists, the two layers are effectively decoupled, and the minimum conductivity at the Dirac point corresponds to double the value observed in monolayer graphene. This remains valid even in the presence of vacancies, hinting that chiral symmetry is still preserved. On the contrary, for low twist angles, the conductivity at the Dirac point depends on the twist angle and is not protected in the presence of disorder. Furthermore, for low angles and in the presence of an applied electric field, we find that the chiral boundary states emerging between AB and BA regions contribute to the dc conductivity, despite the appearance of localized states in the AA regions. The results agree qualitatively with recent transport experiments in low-angle twisted bilayer graphene.

CET89 - CHEMICAL EQUILIBRIUM WITH TRANSPORT PROPERTIES, 1989

Science.gov (United States)

Mcbride, B.

1994-01-01

Scientists and engineers need chemical equilibrium composition data to calculate the theoretical thermodynamic properties of a chemical system. This information is essential in the design and analysis of equipment such as compressors, turbines, nozzles, engines, shock tubes, heat exchangers, and chemical processing equipment. The substantial amount of numerical computation required to obtain equilibrium compositions and transport properties for complex chemical systems led scientists at NASA's Lewis Research Center to develop CET89, a program designed to calculate the thermodynamic and transport properties of these systems. CET89 is a general program which will calculate chemical equilibrium compositions and mixture properties for any chemical system with available thermodynamic data. Generally, mixtures may include condensed and gaseous products. CET89 performs the following operations: it 1) obtains chemical equilibrium compositions for assigned thermodynamic states, 2) calculates dilute-gas transport properties of complex chemical mixtures, 3) obtains Chapman-Jouguet detonation properties for gaseous species, 4) calculates incident and reflected shock properties in terms of assigned velocities, and 5) calculates theoretical rocket performance for both equilibrium and frozen compositions during expansion. The rocket performance function allows the option of assuming either a finite area or an infinite area combustor. CET89 accommodates problems involving up to 24 reactants, 20 elements, and 600 products (400 of which may be condensed). The program includes a library of thermodynamic and transport properties in the form of least squares coefficients for possible reaction products. It includes thermodynamic data for over 1300 gaseous and condensed species and transport data for 151 gases. The subroutines UTHERM and UTRAN convert thermodynamic and transport data to unformatted form for faster processing. The program conforms to the FORTRAN 77 standard, except for

Finite-orbit-width effect and the radial electric field in neoclassical transport phenomena

International Nuclear Information System (INIS)

Satake, S.; Okamoto, M.; Nakajima, N.; Sugama, H.; Yokoyama, M.; Beidler, C.D.

2005-01-01

Modeling and detailed simulation of neoclassical transport phenomena both in 2D and 3D toroidal configurations are shown. The emphasis is put on the effect of finiteness of the drift-orbit width, which brings a non-local nature to neoclassical transport phenomena. Evolution of the self-consistent radial electric field in the framework of neoclassical transport is also investigated. The combination of Monte-Carlo calculation for ion transport and numerical solver of ripple-averaged kinetic equation for electrons makes it possible to calculate neoclassical fluxes and the time evolution of the radial electric field in the whole plasma region, including the finite-orbit-width (FOW) effects and global evolution of geodesic acoustic mode (GAM). The simulation results show that the heat conductivity around the magnetic axis is smaller than that obtained from standard neoclassical theory and that the evolution of GAM oscillation on each flux surface is coupled with other surfaces if the FOW effect is significant. A global simulation of radial electric field evolution in a non-axisymmetric plasma is also shown. (author)

Comparison of all-electric secondary power systems for civil transport

Science.gov (United States)

Renz, David D.

1992-01-01

Three separate studies have shown operational, weight, and cost advantages for commercial subsonic transport aircraft using an all-electric secondary power system. The first study in 1982 showed that all-electric secondary power systems produced the second largest benefit compared to four other technology upgrades. The second study in 1985 showed a 10 percent weight and fuel savings using an all-electric high frequency (20 kHz) secondary power system. The last study in 1991 showed a 2 percent weight savings using today's technology (400 Hz) in an all-electric secondary power system. This paper will compare the 20 kHz and 400 Hz studies, analyze the 2 to 10 percent difference in weight savings and comment on the common benefits of the all-electric secondary power system.

Dielectric and electrical properties of gadolinium-modified lead-zirconate-titanate system

International Nuclear Information System (INIS)

Panigrahi, S.C.; Das, Piyush R.; Parida, B.N.; Padhee, R.; Choudhary, R.N.P.

2014-01-01

Highlights: • Gadolinium modified PZT have very good dielectric and ferroelectric properties. • The impedance analysis of shows grain and grain boundary phenomena. • Electrical properties of the compounds show very good transport properties. • Piezoelectric coefficient of the samples have higher values. - Abstract: The gadolinium (Gd) modified lead zirconate titanate (PbZr,TiO 3 ) ceramics with Zr/Ti = 48/52 (i.e., near morphotropic phase boundary (MPB)) in a general chemical formula Pb 1−x Gd x (Zr 0.48 Ti 0.52 ) 1−x/4 O 3 (PGZT; x = 0, 0.07, 0.10 and 0.12) have been synthesized using a high-temperature solid-state reaction method. Preliminary structural analysis using X-ray powder diffraction (XRD) shows the formation of a single-phase tetragonal structure of the compounds. Detailed studies of dielectric parameters of PGZT exhibit the diffuse phase transition but non-relaxor characteristics in the material for the higher concentration of gadolinium. The ac conductivity spectra of PGZT are found to obey Jonscher’s universal power law. The electrical impedance parameters of PGZT (near MPB) were obtained in a wide range of temperature (25–500 °C) and frequency (1–1000 kHz) using complex impedance spectroscopy (CIS) technique. Detailed analysis of these parameters shows that bulk (grain) and grain boundary resistance have significant effect on the total impedance of the materials. Temperature dependence of hysteresis characteristics of PGZT confirms that the phase transition parameter of the material is strongly affected by the substitution of Gd at the Pb-sites

Structural, magnetic and electrical transport properties in electron-doped La{sub 0.85}Hf{sub 0.15}MnO{sub 3} epitaxial film

Energy Technology Data Exchange (ETDEWEB)

Han, Li-an; Zhu, Hua-ze; Zhang, Tao [Xi' an University of Science and Technology, Department of Applied Physics, Xi' an (China); Ma, Zi-wei [Yuncheng University, Department of Physics and Electronic Engineering, Yuncheng (China); Chen, Chang-le [Northwestern Polytechnical University, Department of Applied Physics, Xi' an (China)

2017-03-15

Using a pulsed laser deposition method, the electron-doped La{sub 0.85}Hf{sub 0.15}MnO{sub 3} (LHMO) film with the thickness of 90 nm was epitaxially grown on LaAlO{sub 3} (001) single crystal substrate. The structural, magnetic and electrical transport properties of the film have been studied comprehensively. The X-ray diffraction patterns confirm that LHMO film is of single phase, good quality and c axis orientation. The film undergoes a ferromagnetic-like ordering to paramagnetic states at T{sub C} =280 K. Moreover, a spin glass behavior observed in the film may be attributed to the strain effects. Using the percolation theory, we have analyzed the resistivity data ρ (T) of the film and given an excellent fit in the whole temperature range. Particularly, large temperature coefficient of resistance of 11.27% K{sup -} {sup 1} has been discovered near sub-room-temperature, indicating that LHMO film could be useful for bolometric applications. (orig.)

Irradiation effects on electrical properties of DNA solution/Al Schottky diodes

Science.gov (United States)

Al-Ta'ii, Hassan Maktuff Jaber; Periasamy, Vengadesh; Iwamoto, Mitsumasa

2018-04-01

Deoxyribonucleic acid (DNA) has emerged as one of the most exciting organic material and as such extensively studied as a smart electronic material since the last few decades. DNA molecules have been reported to be utilized in the fabrication of small-scaled sensors and devices. In this current work, the effect of alpha radiation on the electrical properties of an Al/DNA/Al device using DNA solution was studied. It was observed that the carrier transport was governed by electrical interface properties at the Al-DNA interface. Current ( I)-voltage ( V) curves were analyzed by employing the interface limited Schottky current equations, i.e., conventional and Cheung and Cheung's models. Schottky parameters such as ideality factor, barrier height and series resistance were also determined. The extracted barrier height of the Schottky contact before and after radiation was calculated as 0.7845, 0.7877, 0.7948 and 0.7874 eV for the non-radiated, 12, 24 and 36 mGy, respectively. Series resistance of the structure was found to decline with the increase in the irradiation, which was due to the increase in the free radical root effects in charge carriers in the DNA solution. Results pertaining to the electronic profiles obtained in this work may provide a better understanding for the development of precise and rapid radiation sensors using DNA solution.

Bentonite electrical conductivity: a model based on series–parallel transport

KAUST Repository

Lima, Ana T.; Loch, J. P. Gustav; Kleingeld, Pieter J.

2010-01-01

discussion, and subject of many studies. However, to understand the behaviour of such an expansive and plastic material under the influence of an electric field, the perception of its electrical properties is essential. This work serves to compare existing

Enhanced rotation velocities and electric fields, sub-neoclassical energy transport and density pinch from revisited neoclassical theory

International Nuclear Information System (INIS)

Rogister, A.

1998-01-01

We show that the large negative radial electric fields which are measured in front of the separatrix in H-mode discharges are easily explainable on the basis of the rigorous 'revisited' neoclassical theory, including finite Larmor radii and inertia effects that was published earlier (Rogister A 1994 Phys. Plasmas 1 619); the same theory naturally leads to sub-neoclassical energy transport and novel particle pinch terms. The calculation has so far been developed only in the high collisionality regime: step sizes comparable to gradient-scale sizes are therefore not required to explain observed properties! Based on the analysis, we conclude that the radial electric field profile develops a well in front of the separatrix when the plasma is unable to sustain ambipolar flows otherwise. (author)

Nonlinear transport properties of non-ideal systems

International Nuclear Information System (INIS)

Pavlov, G A

2009-01-01

The theory of nonlinear transport is elaborated to determine the Burnett transport properties of non-ideal multi-element plasma and neutral systems. The procedure for the comparison of the phenomenological conservation equations of a continuous dense medium and the microscopic equations for dynamical variable operators is used for the definition of these properties. The Mori algorithm is developed to derive the equations of motion of dynamical value operators of a non-ideal system in the form of the generalized nonlinear Langevin equations. In consequence, the microscopic expressions of transport coefficients corresponding to second-order thermal disturbances (temperature, mass velocity, etc) have been found in the long wavelength and low frequency limits

Sustainable transport strategy for promoting zero-emission electric scooters in Taiwan

Energy Technology Data Exchange (ETDEWEB)

Hwang, Jenn Jiang [Department of Greenergy, National University of Tainan, Tainan 700 (China)

2010-06-15

In Taiwan, the government considers the zero-emission scooters to be a sustainable form of transport like walking, cycling and public transport, which play a vital role to support sustainable urban mobility. Therefore, the development of zero-emission scooters is an important strategy in constructing the sustainable transport network of Taiwan. It is also the government's priorities about the policy of emission-reduction and energy-conservation in the transportation sector. Recently, Taiwan launched a new program for subsidy of purchasing zero-emission scooters, which aimed to shift the petroleum-powered scooters to the electric scooters. The present paper is providing an update review of the promotional programs in developing zero-emission scooters in Taiwan. It introduces the status of the establishment and progress of policy, standards, subsidies to users and manufacturers, practice infrastructure, and technology development. Moreover, the contribution of replacing petrol scooters by zero-emission scooters such as battery-powered electric scooters and fuel cell scooters to reduction in greenhouse gas (GHG) emission and improvement in energy efficiency is evaluated. (author)

Thermodynamic and transport properties of gaseous tetrafluoromethane in chemical equilibrium

Science.gov (United States)

Hunt, J. L.; Boney, L. R.

1973-01-01

Equations and in computer code are presented for the thermodynamic and transport properties of gaseous, undissociated tetrafluoromethane (CF4) in chemical equilibrium. The computer code calculates the thermodynamic and transport properties of CF4 when given any two of five thermodynamic variables (entropy, temperature, volume, pressure, and enthalpy). Equilibrium thermodynamic and transport property data are tabulated and pressure-enthalpy diagrams are presented.

Measurement of Deterioration of Frying Oil Using Electrical Properties

OpenAIRE

羽倉, 義雄; 佐々木, 芳浩; 鈴木, 寛一

2006-01-01

In this study, the relationship between the electrical properties of frying oil (relative dielectric constant and conductance) and its deterioration indicators (acid value, amounts of polymerized triacylglycerols and chromaticity) were examined, focusing on the changes in electrical properties that accompany deterioration. The samples of frying oil used in this experiment were collected from fried food processing sites (school, hospital and factory feeding centers) and were collected at closi...

Effect of spin reorientation on magnetocaloric and transport properties of NdAl{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Souza, M.V. de, E-mail: marcos_vinicios@hotmail.com [Núcleo de Pós-Graduação em Física, Campus Prof. José Aloísio de Campos, UFS, 49100-000 São Cristóvão, SE (Brazil); Silva, J.A. da [Núcleo de Pós-Graduação em Física, Campus Prof. José Aloísio de Campos, UFS, 49100-000 São Cristóvão, SE (Brazil); Silva, L.S. [Núcleo de Pós-Graduação em Física, Campus Prof. José Aloísio de Campos, UFS, 49100-000 São Cristóvão, SE (Brazil); Instituto Federal de Tocantins, IFTO – Campus Colinas do Tocantins, AV. Bernardo Sayao S/N, Chácara Raio de Sol, Setor Santa Maria, CEP 77760-000 Colinas do Tocantins, TO (Brazil)

2017-01-01

We report the magneto-thermal and resistive properties of rare-earth dialuminide NdAl{sub 2}, including spin reorientation transition. To this purpose, we used a theoretical model that considers the interactions of exchange and Zeeman, besides the anisotropy due to the electrical crystal field. The theoretical results obtained were compared to experimental data of the NdAl{sub 2} in single crystal and bulk forms. Explicitly, we have calculated the anisotropic variation of magnetic entropy with the magnetic field oriented along the three principal crystallographic directions: [100], [110], and [111] of NdAl{sub 2} single crystal, where a signature of the spin reorientation is observed in the [110] and [111] directions. Moreover, of magnetoresistivity we consider the applied magnetic field along the crystallographic directions [100] and [110]. In turn, for the polycrystalline form, the good agreement between theory and experiment confirms the presence of spin reorientation, which was predicted theoretically in magnetization curves. - Highlights: • Modeling of the thermodynamics quantities in NdAl{sub 2} single crystal and policrystal. • Modeling of the transport properties in NdAl{sub 2} single crystal. • Effect of reorientation of spin on caloric and transport properties.

Transport properties site descriptive model. Guidelines for evaluation and modelling

International Nuclear Information System (INIS)

Berglund, Sten; Selroos, Jan-Olof

2004-04-01

This report describes a strategy for the development of Transport Properties Site Descriptive Models within the SKB Site Investigation programme. Similar reports have been produced for the other disciplines in the site descriptive modelling (Geology, Hydrogeology, Hydrogeochemistry, Rock mechanics, Thermal properties, and Surface ecosystems). These reports are intended to guide the site descriptive modelling, but also to provide the authorities with an overview of modelling work that will be performed. The site descriptive modelling of transport properties is presented in this report and in the associated 'Strategy for the use of laboratory methods in the site investigations programme for the transport properties of the rock', which describes laboratory measurements and data evaluations. Specifically, the objectives of the present report are to: Present a description that gives an overview of the strategy for developing Site Descriptive Models, and which sets the transport modelling into this general context. Provide a structure for developing Transport Properties Site Descriptive Models that facilitates efficient modelling and comparisons between different sites. Provide guidelines on specific modelling issues where methodological consistency is judged to be of special importance, or where there is no general consensus on the modelling approach. The objectives of the site descriptive modelling process and the resulting Transport Properties Site Descriptive Models are to: Provide transport parameters for Safety Assessment. Describe the geoscientific basis for the transport model, including the qualitative and quantitative data that are of importance for the assessment of uncertainties and confidence in the transport description, and for the understanding of the processes at the sites. Provide transport parameters for use within other discipline-specific programmes. Contribute to the integrated evaluation of the investigated sites. The site descriptive modelling of

Coefficient of electrical transport vacuum arc for metals and alloys

International Nuclear Information System (INIS)

Markov, G.V.; Ehjzner, B.A.

1998-01-01

In this article the authors propose formulas for estimation coefficient of electrical transport vacuum arc for metals and alloys. They also represent results of analysis principal physical processes which take place in cathode spot vacuum arc

Effects of lithium doping on microstructure, electrical properties, and chemical bonds of sol-gel derived NKN thin films

Energy Technology Data Exchange (ETDEWEB)

Lin, Chun-Cheng [Department of Electrical Engineering, National Cheng Kung University, Tainan 701, Taiwan (China); Department of Mathematic and Physical Sciences, R.O.C. Air Force Academy, Kaohsiung 820, Taiwan (China); Chen, Chan-Ching; Weng, Chung-Ming [Department of Electrical Engineering, National Cheng Kung University, Tainan 701, Taiwan (China); Chu, Sheng-Yuan, E-mail: chusy@mail.ncku.edu.tw [Department of Electrical Engineering, National Cheng Kung University, Tainan 701, Taiwan (China); Center for Micro/Nano Science and Technology, National Cheng Kung University, Tainan 701, Taiwan (China); Hong, Cheng-Shong [Department of Electronic Engineering, National Kaohsiung Normal University, Kaohsiung 802, Taiwan (China); Tsai, Cheng-Che [Department of Digital Game and Animation Design, Tung-Fang Design University, Kaohsiung 829, Taiwan (China)

2015-02-28

Highly (100/110) oriented lead-free Li{sub x}(Na{sub 0.5}K{sub 0.5}){sub 1−x}NbO{sub 3} (LNKN, x = 0, 0.02, 0.04, and 0.06) thin films are fabricated on Pt/Ti/SiO{sub 2}/Si substrates via a sol-gel processing method. The lithium (Li) dopants modify the microstructure and chemical bonds of the LNKN films, and therefore improve their electrical properties. The optimal values of the remnant polarization (P{sub r} = 14.3 μC/cm{sup 2}), piezoelectric coefficient (d{sub 33} = 48.1 pm/V), and leakage current (<10{sup −5} A/cm{sup 2}) are obtained for a lithium addition of x = 0.04 (i.e., 4 at. %). The observation results suggest that the superior electrical properties are the result of an improved crystallization, a larger grain size, and a smoother surface morphology. It is shown that the ion transport mechanism is dominated by an Ohmic behavior under low electric fields and the Poole-Frenkel emission effect under high electric fields.

Surface morphology, structural and electrical properties of RF ...

Indian Academy of Sciences (India)

2018-05-19

May 19, 2018 ... ITO thin films; sputtering; structure; electrical properties; AFM; Hall effect. 1. Introduction ... ness range (61–768 nm) and to see if this system present properties that .... using the Bragg equation, and the relation linking the inter-.

Tuning the Transport Properties of Layered Materials for Thermoelectric Applications using First-Principles Calculations

KAUST Repository

Saeed, Yasir

2014-05-11

Thermoelectric materials can convert waste heat into electric power and thus provide a way to reduce the dependence on fossil fuels. Our aim is to model the underlying materials properties and, in particular, the transport as controlled by electrons and lattice vibrations. The goal is to develop an understanding of the thermoelectric properties of selected materials at a fundamental level. The structural, electronic, optical, and phononic properties are studied in order to tune the transport, focusing on KxRhO2, NaxRhO2, PtSb2 and Bi2Se3. The investigations are based on density functional theory as implemented in the all electron linearized augmented plane wave plus local orbitals WIEN2k and pseudo potential Quantum-ESPRESSO codes. The thermoelectric properties are derived from Boltzmann transport theory under the constant relaxation time approximation, using the BoltzTraP code. We will discuss first the changes in the electronic band structure under variation of the cation concentration in layered KxRhO2 in the 2H phase and NaxRhO2 in the 3R phase. We will also study the hydrated phase. The deformations of the RhO6 octahedra turn out to govern the thermoelectric properties, where the high Seebeck coefficient results from ”pudding mold" bands. We investigate the thermoelectric properties of electron and hole doped PtSb2, which is not a layered material but shares “pudding mold" bands. PtSb2 has a high Seebeck coefficient at room temperature, which increases significantly under As alloying by bandgap opening and reduction of the lattice thermal conductivity. Bi2Se3 (bulk and thin film) has a larger bandgap then the well-known thermoelectric material Bi2Te3, which is important at high temperature. The structural stability, electronic structure, and transport properties of one to six quintuple layers of Bi2Se3 will be discussed. We also address the effect of strain on a single quintuple layer by phonon band structures. We will analyze the electronic and transport

Modelling the electrical properties of tissue as a porous medium

International Nuclear Information System (INIS)

Smye, S W; Evans, C J; Robinson, M P; Sleeman, B D

2007-01-01

Models of the electrical properties of biological tissue have been the subject of many studies. These models have sought to explain aspects of the dielectric dispersion of tissue. This paper develops a mathematical model of the complex permittivity of tissue as a function of frequency f, in the range 10 4 7 Hz, which is derived from a formulation used to describe the complex permittivity of porous media. The model introduces two parameters, porosity and percolation probability, to the description of the electrical properties of any tissue which comprises a random arrangement of cells. The complex permittivity for a plausible porosity and percolation probability distribution is calculated and compared with the published measured electrical properties of liver tissue. Broad agreement with the experimental data is noted. It is suggested that future detailed experimental measurements should be undertaken to validate the model. The model may be a more convenient method of parameterizing the electrical properties of biological tissue and subsequent measurement of these parameters in a range of tissues may yield information of biological and clinical significance

Temperature-dependent electrical property transition of graphene oxide paper

International Nuclear Information System (INIS)

Huang Xingyi; Jiang Pingkai; Zhi Chunyi; Golberg, Dmitri; Bando, Yoshio; Tanaka, Toshikatsu

2012-01-01

Reduction of graphene oxide is primarily important because different reduction methods may result in graphene with totally different properties. For systematically exploring the reduction of graphene oxide, studies of the temperature-dependent electrical properties of graphene oxide (GO) are urgently required. In this work, for the first time, broadband dielectric spectroscopy was used to carry out an in situ investigation on the transition of the electrical properties of GO paper from −40 to 150 °C. The results clearly reveal a very interesting four-stage transition of electrical properties of GO paper with increasing temperature: insulator below 10 °C (stage 1), semiconductor at between 10 and 90 °C (stage 2), insulator at between 90 and 100 °C (stage 3), and semiconductor again at above 100 °C (stage 4). Subsequently, the transition mechanism was discussed in combination with detailed dielectric properties, microstructure and thermogravimetric analyses. It is suggested that the temperature-dependent transition of electronic properties of GO is closely associated with the ion mobility, water molecules removal and the reduction of GO in the GO paper. Most importantly, the present work clearly demonstrates the reduction of GO paper starts at above 100 °C. (paper)

Electrical transport through a metal-molecule-metal junction; Transport electrique a travers une jonction metal-molecule-metal

Energy Technology Data Exchange (ETDEWEB)

Kergueris, Ch

1998-12-17

We investigate the electrical transport through a very few molecules connected to metallic electrodes at room temperature. First, the state of the art in molecular electronics is outlined. We present the most convincing molecular devices reported so far in the literature and the theoretical tools available to analyze the electron transport mechanism through a molecular junction. Second, we describe the use of mechanically controllable break junctions to investigate the electron transport properties through a metal-molecule-metal junction. Two kindsof molecules were adsorbed on the two facing gold electrodes, dodecane-thiol (DT) and bis-thiol-ter-thiophene ({alpha},{omega} T3), that are basically expected to behave as an insulator and as a molecular wire, respectively. In the latter case, we study the chemical reactivity of the molecule and show that {alpha},{omega} T3 is chemically adsorbed on gold electrodes. Current-voltage characteristics of the junction were observed at room temperature. The Gold-DT-Gold junction behaves as a simple metal-insulator-metal junction. On the other hand, the electron transport through a Gold-{alpha},{omega} T3-Gold junction explicitly involves the electronic structure of the molecule which gives rise to step-like features in the current-voltage characteristics. The measured zero bias conductance is interpreted using the scattering theory. At high bias, we discuss two different models: a coherent model where the electron has no time to be completely re-localized in the molecule and a sequential model where the electron is localized in the molecule during the transfer. Finally, we show that the mechanical action of decreasing the inter-electrodes spacing can be used to induce a strong modification of the current-voltage characteristics. (author)

Modulation of transport properties of optimally doped La{sub 1.85}Sr{sub 0.15}CuO{sub 4} thin films via electric field modification of the grain boundaries

Energy Technology Data Exchange (ETDEWEB)

Hassan, Muhammad Umair [Center for Micro and Nano Devices, Department of Physics, COMSATS Institute of Information Technology, Islamabad (Pakistan); Cavendish Laboratory, Cambridge (United Kingdom); Wimbush, Stuart C. [The MacDiarmid Institute for Advanced Materials and Nanotechnology, Victoria University of Wellington (New Zealand)

2015-09-15

Modulation of the transport properties of a superconducting La{sub 1.85}Sr{sub 0.15}CuO{sub 4}-based ionic-liquid gated transistor has been achieved. For an applied gate bias V{sub g} ≥ 2 V, the characteristic sheet resistivity vs. temperature (R{sub s}-T) curves exhibit a fully reversible foot feature below the superconducting transition temperature (T{sub c}). In contrast to the behaviour expected from the large charge carrier density of this high-T{sub c} superconductor material, the normal state conductance above T{sub c} also exhibits a large modulation, indicating a larger charge screening length than that predicted from a simple Thomas-Fermi model. We regard these changes as due to electrostatic modification of the charge density at structural imperfections such as grain boundaries present within the sample. Such modification alters the coupling between superconducting domains and dictates the overall R{sub s}-T trend of the gated film. To explain our findings, we employ Mannhart's model of electronic band bending at the grain boundaries and propose that this band bending can be modulated by large electric fields resulting in the observed modulation of the transport properties of the device. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Transport properties of diazonium functionalized graphene: chiral two-dimensional hole gases

International Nuclear Information System (INIS)

Huang Ping; Jing Long; Zhu Huarui; Gao Xueyun

2012-01-01

The electric transport properties of diazonium functionalized graphene (DFG) were investigated. The temperature dependence of the resistivity (ρ-T) and the Shubnikov-de Haas oscillation of the DFG revealed two-dimensional hole gas (2DHG) behaviors. The DFGs exhibited unusual weak localization behaviors in which both inelastic and chirality-breaking elastic scattering processes should be taken into account, meaning that graphene chirality was maintained. Because of the giant decrease in the diffusion coefficient, the scattering rates remained relatively low in the presence of suppression of the scattering lengths. The decreases of both the mean free path and the Fermi velocity were responsible for the suppression of the diffusion coefficient and hence the charge mobility. (paper)

Electronic band structure, magnetic, transport and thermodynamic properties of In-filled skutterudites InxCo4Sb12

International Nuclear Information System (INIS)

Leszczynski, J; Da Ros, V; Lenoir, B; Dauscher, A; Candolfi, C; Masschelein, P; Hejtmanek, J; Kutorasinski, K; Tobola, J; Smith, R I; Stiewe, C; Müller, E

2013-01-01

The thermoelectric and thermodynamic properties of polycrystalline In x Co 4 Sb 12 (0.0 ⩽ x ⩽ 0.26) skutterudites were investigated and analysed between 2 and 800 K by means of electrical resistivity, thermopower, thermal conductivity and specific heat measurements. Hall effect, sound velocity and thermal expansion measurements were also made in order to gain insights into the transport and elastic properties of these compounds. The impact of the In filling on the crystal structure as well as the thermal dynamics of the In atoms were tracked down to 4 K using powder neutron diffraction experiments. Analyses of the transport data were compared with the evolution of the electronic band structure with x determined theoretically within the Korringa–Kohn–Rostoker method with the coherent potential approximation. These calculations indicate that In gives rise to a remarkably large p-like density of states located at the conduction band edge. The electrical properties show typical trends of heavily doped semiconductors regardless of the In content. The thermal transport in CoSb 3 is strongly influenced by the presence of In in the voids of the crystal structure resulting in a drop in the lattice thermal conductivity values in the whole temperature range. The low value of the Grüneisen parameter suggests that this decrease mainly originates from enhanced mass-fluctuations and point-defect scattering mechanisms. The highest thermoelectric figure of merit ZT ∼ 1.0 at 750 K was achieved at the maximum In filling fraction, i.e. for x = 0.26. (paper)

The role of fluctuation-induced transport in a toroidal plasma with strong radial electric fields

Science.gov (United States)

Roth, J. R.; Krawczonek, W. M.; Powers, E. J.; Hong, J. Y.; Kim, Y. C.

1981-01-01

Previous work employing digitally implemented spectral analysis techniques is extended to demonstrate that radial fluctuation-induced transport is the dominant ion transport mechanism in an electric field dominated toroidal plasma. Such transport can be made to occur against a density gradient, and hence may have a very beneficial effect on confinement in toroidal plasmas of fusion interest. It is shown that Bohm or classical diffusion down a density gradient, the collisional Pedersen-current mechanism, and the collisionless electric field gradient mechanism described by Cole (1976) all played a minor role, if any, in the radial transport of this plasma.

Effects of finite-β and radial electric fields on neoclassical transport in the Large Helical Device

International Nuclear Information System (INIS)

Kanno, R.; Nakajima, N.; Sugama, H.; Okamoto, M.; Ogawa, Y.

1997-01-01

Effects of finite-β and radial electric fields on the neoclassical transport in the Large Helical Device are investigated with the DKES (Drift Kinetic Equation Solver) code. In the finite-β configuration, even orbits of deeply trapped particles deviate significantly from magnetic flux surfaces. Thus, neoclassical ripple transport coefficients in the finite-β configuration are several times larger than those in the vacuum configuration under the same condition of temperatures and radial electric fields. When the plasma temperature is several keV, a bifurcation of the electric fields appears under the ambipolarity condition, and sufficient large radial electric fields can be generated. As a result, the ExB drift rectifies orbits of particles and improves significantly the transport coefficients in the finite-β configuration. (author)

Electric Conductivity of Phosphorus Nanowires

International Nuclear Information System (INIS)

Jing-Xiang, Zhang; Hui, Li; Xue-Qing, Zhang; Kim-Meow, Liew

2009-01-01

We present the structures and electrical transport properties of nanowires made from different strands of phosphorus chains encapsulated in carbon nanotubes. Optimized by density function theory, our results indicate that the conductance spectra reveal an oscillation dependence on the size of wires. It can be seen from the density of states and current-voltage curves that the structure of nanowires affects their properties greatly. Among them, the DNA-like double-helical phosphorus nanowire exhibits the distinct characteristic of an approximately linear I – V relationship and has a higher conductance than others. The transport properties of phosphorus nanowires are highly correlated with their microstructures. (condensed matter: structure, mechanical and thermal properties)

Electrical transport properties of CuXSn1-X metallic glasses

Science.gov (United States)

Vora, A. M.; Gajjar, P. N.

2018-05-01

In the present paper, we report the electrical resistivity (ρ), the thermoelectric power (TEP) and thermal conductivity (σ) of CuXSn1-X metallic glasses computed from Faber-Ziman formulation with Percus-Yevic (PY) hard sphere structure factors of Ashcroft and Langreth. Our well-recognized model potential is used to represent ionic interaction for the first time with seven local field correction functions due to Hartree (H), Hubbard-Sham (HS), Vashishta-Singwi (VS), Taylor (T), Ichimaru-Utsumi (IU), Farid et al. (F) and Sarkar et al. (S) in the present computation and found suitable for such study. The percentile influence of various local field corrections with respect to Hartree (H) is found in the range of 17.35%-71.55%. It is concluded that, the comparison of present and experimental findings of electrical resistivity (ρ) is highly promising.

Simultaneous measurements of transport and poroelastic properties of rocks.

Science.gov (United States)

Hasanov, Azar K; Prasad, Manika; Batzle, Michael L

2017-12-01

A novel laboratory apparatus has been developed for simultaneous measurements of transport and poroelastic rock properties. These transport and poroelastic properties at reservoir pressure and temperature conditions are required inputs for various geoscience applications, such as reservoir simulation, basin modeling, or modeling of pore pressure generation. Traditionally, the transport and poroelastic properties are measured separately using, for example, the oscillating pore pressure method to measure hydraulic transport properties, static strain measurements for elastic properties, and pore volumometry for storage capacity. In addition to time, the separate set of measurements require either aliquot cores or subjecting the same core to multiple pressure tests. We modified the oscillating pore pressure method to build an experimental setup, capable of measuring permeability, storage capacity, and pseudo-bulk modulus of rocks simultaneously. We present here the test method, calibration measurements (capillary tube), and sample measurements (sandstone) of permeability and storage capacity at reservoir conditions. We establish that hydraulically measured storage capacities were overestimated by an order of magnitude when compared to elastically derived ones. Our concurrent measurement of elastic properties during the hydraulic experiment provides an independent constraint on storage capacity.

MW-Class Electric Propulsion System Designs for Mars Cargo Transport

Science.gov (United States)

Gilland, James H.; LaPointe, Michael R.; Oleson, Steven; Mercer, Carolyn; Pencil, Eric; Maosn, Lee

2011-01-01

Multi-kilowatt electric propulsion systems are well developed and have been used on commercial and military satellites in Earth orbit for several years. Ion and Hall thrusters have also propelled robotic spacecraft to encounters with asteroids, the Moon, and minor planetary bodies within the solar system. High power electric propulsion systems are currently being considered to support piloted missions to near earth asteroids, as cargo transport for sustained lunar or Mars exploration, and for very high-power piloted missions to Mars and the outer planets. Using NASA Mars Design Architecture 5.0 as a reference, a preliminary parametric analysis was performed to determine the suitability of a nuclear powered, MW-class electric propulsion system for Mars cargo transport. For this initial analysis, high power 100-kW Hall thrusters and 250-kW VASIMR engines were separately evaluated to determine optimum vehicle architecture and estimated performance. The DRA 5.0 cargo mission closed for both propulsion options, delivering a 100 t payload to Mars orbit and reducing the number of heavy lift launch vehicles from five in the baseline DRA 5.0 architecture to two using electric propulsion. Under an imposed single engine-out mission success criteria, the VASIMR system took longer to reach Mars than did the Hall system, arising from the need to operate the VASIMR thrusters in pairs during the spiral out from low Earth orbit.

Solar electric propulsion for Mars transport vehicles

Science.gov (United States)

Hickman, J. M.; Curtis, H. B.; Alexander, S. W.; Gilland, J. H.; Hack, K. J.; Lawrence, C.; Swartz, C. K.

1990-01-01

Solar electric propulsion (SEP) is an alternative to chemical and nuclear powered propulsion systems for both piloted and unpiloted Mars transport vehicles. Photovoltaic solar cell and array technologies were evaluated as components of SEP power systems. Of the systems considered, the SEP power system composed of multijunction solar cells in an ENTECH domed fresnel concentrator array had the least array mass and area. Trip times to Mars optimized for minimum propellant mass were calculated. Additionally, a preliminary vehicle concept was designed.

Petroleum electrical properties characterization; Caracterizaco de propriedades eletricas de petroleo

Energy Technology Data Exchange (ETDEWEB)

Ueti, Edson; Sens, Marcio Antonio [Centro de Pesquisas de Energia Eletrica (CEPEL), Rio de Janeiro, RJ (Brazil)], e-mail: ueti@cepel.br

2006-07-01

Presently, petroleum wells consist predominantly of heavy type petroleum, that is submitted to decantation and separation of water, through desalinisation process. If this process is not efficient, the metallic piping will be severely corroded during refining. Hence, the knowledge of petroleum electric properties is essential for optimizing the separation of water from petroleum, by indicating its humidity in laboratory testing conditions. The present work shows an experimental procedure based on disposable cells for electric characterization of liquid polymeric materials. The use of standard cells is unfeasible, due to the petroleum physical characteristics. The procedures for the evaluation of electric properties shown in this work are applied for dielectric constant values up to 200 kHz, as well as for the electric conductivity in direct current and the electrical strength in industrial frequency. (author)

Transport coefficients for electrons in argon in crossed electric and magnetic rf fields

International Nuclear Information System (INIS)

Raspopovic, Z M; Dujko, S; Makabe, T; Petrovic, Z Lj

2005-01-01

Monte Carlo simulations of electron transport have been performed in crossed electric and magnetic rf fields in argon. It was found that a magnetic field strongly affects electron transport, producing complex behaviour of the transport coefficients that cannot be predicted on the basis of dc field theory. In particular, it is important that a magnetic field, if it has sufficiently high amplitude, allows energy gain from the electric field only over a brief period of time, which leads to a pulse of directed motion and consequently to cyclotron oscillations being imprinted on the transport coefficients. Furthermore, this may lead to negative diffusion. The behaviour of drift velocities is also interesting, with a linear (sawtooth) dependence for the perpendicular drift velocity and bursts of drift for the longitudinal. Non-conservative effects are, on the other hand, reduced by the increasing magnetic field

Unsaturated Zone and Saturated Zone Transport Properties (U0100)

Energy Technology Data Exchange (ETDEWEB)

J. Conca

2000-12-20

This Analysis/Model Report (AMR) summarizes transport properties for the lower unsaturated zone hydrogeologic units and the saturated zone at Yucca Mountain and provides a summary of data from the Busted Butte Unsaturated Zone Transport Test (UZTT). The purpose of this report is to summarize the sorption and transport knowledge relevant to flow and transport in the units below Yucca Mountain and to provide backup documentation for the sorption parameters decided upon for each rock type. Because of the complexity of processes such as sorption, and because of the lack of direct data for many conditions that may be relevant for Yucca Mountain, data from systems outside of Yucca Mountain are also included. The data reported in this AMR will be used in Total System Performance Assessment (TSPA) calculations and as general scientific support for various Process Model Reports (PMRs) requiring knowledge of the transport properties of different materials. This report provides, but is not limited to, sorption coefficients and other relevant thermodynamic and transport properties for the radioisotopes of concern, especially neptunium (Np), plutonium (Pu), Uranium (U), technetium (Tc), iodine (I), and selenium (Se). The unsaturated-zone (UZ) transport properties in the vitric Calico Hills (CHv) are discussed, as are colloidal transport data based on the Busted Butte UZTT, the saturated tuff, and alluvium. These values were determined through expert elicitation, direct measurements, and data analysis. The transport parameters include information on interactions of the fractures and matrix. In addition, core matrix permeability data from the Busted Butte UZTT are summarized by both percent alteration and dispersion.

Unsaturated Zone and Saturated Zone Transport Properties (U0100)

International Nuclear Information System (INIS)

Conca, J.

2000-01-01

This Analysis/Model Report (AMR) summarizes transport properties for the lower unsaturated zone hydrogeologic units and the saturated zone at Yucca Mountain and provides a summary of data from the Busted Butte Unsaturated Zone Transport Test (UZTT). The purpose of this report is to summarize the sorption and transport knowledge relevant to flow and transport in the units below Yucca Mountain and to provide backup documentation for the sorption parameters decided upon for each rock type. Because of the complexity of processes such as sorption, and because of the lack of direct data for many conditions that may be relevant for Yucca Mountain, data from systems outside of Yucca Mountain are also included. The data reported in this AMR will be used in Total System Performance Assessment (TSPA) calculations and as general scientific support for various Process Model Reports (PMRs) requiring knowledge of the transport properties of different materials. This report provides, but is not limited to, sorption coefficients and other relevant thermodynamic and transport properties for the radioisotopes of concern, especially neptunium (Np), plutonium (Pu), Uranium (U), technetium (Tc), iodine (I), and selenium (Se). The unsaturated-zone (UZ) transport properties in the vitric Calico Hills (CHv) are discussed, as are colloidal transport data based on the Busted Butte UZTT, the saturated tuff, and alluvium. These values were determined through expert elicitation, direct measurements, and data analysis. The transport parameters include information on interactions of the fractures and matrix. In addition, core matrix permeability data from the Busted Butte UZTT are summarized by both percent alteration and dispersion

Railway diagnosis of electric transport

Directory of Open Access Journals (Sweden)

Yushkov Vladimir Sergeevich

2015-01-01

Full Text Available The increase in noise level at cities is increasing the requirements to functional interaction of road users - pedestrians and drivers - with the parameters of the environment as a leading component of Afferentation synthesis in the complicated complex of locomotive activity. City noise is one of the most widespread factors of unfavorable living and working conditions. The noise of high intensity provokes diseases, lowers labor activity. At present, many large cities pay much attention to electric vehicles. The authors present an analysis of the poor state of tram track in areas of high noise and vibration of car and under-sleeper base design. A negative effect of noise and vibration on the formation of urban areas environment is shown as well as the impact of these conditions on the person. The advantages of the application of electric transport are specified, noise displacement curve of railway and under sleeper base is plotted depending on the frequency of the applied load and the modulus of elasticity, as well as under sleeper base vibroacceleration depending on time. The authors offer a systematic study on the basis of a mathematical model of the sources of noise in the process of a tram motion.

Correlation of nanostructure and charge transport properties of oxidized a -SiC:H films

Energy Technology Data Exchange (ETDEWEB)

Gordienko, S.O.; Nazarov, A.N.; Vasin, A.V.; Rusavsky, A.V.; Lysenko, V.S. [Lashkaryov Institute of Semiconductor Physics, National Academy of Sciences of Ukraine, Prospekt Nauki 41, 03028 Kyiv (Ukraine)

2012-06-15

This paper considers the influence of low temperature oxidation on structural and electrical properties of amorphous carbon-rich a -Si{sub 1-x}C{sub x}:H thin films fabricated by reactive RF magnetron sputtering. It is shown that oxidation leads to formation of SiO{sub x} matrix with graphite-like carbon inclusions. Such conductive precipitates has a strong effect on charge transport in oxidized a -Si{sub 1-x}C{sub x}:H films (copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Structural and transport properties of Sn-Mg alloys

International Nuclear Information System (INIS)

Meydaneri, F.; Saatci, E.; Oezdemir, M.; Ari, M.; Durmus, S.

2010-01-01

The structural and temperature dependence transport of Sn-Mg alloys have been investigated for five different samples (Pure Sn, Sn-1.0 wt % Mg , Sn-2.0 wt % Mg , Sn-6.0 wt.% Mg and Pure Mg). Scanning Electron Microscopy (SEM), x-ray diffraction (XRD) and Energy Dispersive x-ray Analysis (EDX) measurements were carried out in order to clarify the structural properties of the samples. It has been found that, the samples have tetragonal crystal symmetry except the pure Mg which has hexagonal crystal symmetry. The cell parameters decrease slightly with addition of Mg element. The SEM micrographs of the samples show that, the samples have smooth surfaces with clear grain boundary. There is no crack, porosity or defects on the surfaces. The electrical resistivity of the samples increases almost linearly with the increasing temperature, which were measured by four-point probe technique. The thermal conductivity values are in between 0.60-1.00 W/Km, which are decrease slightly with temperature and increase with composition of Mg. The thermal conductivity values of the alloys are in between the values of the pure samples. Thermal conductivity results of the alloys have been compared with available other studies and a good agreement has been seen between the results. In addition, the temperature coefficients of electrical resistivity and thermal conductivity have been determined, which are independent with the compositions of alloying elements

High-temperature electrical properties of the Bi2.1Sr1.9(Ca1-xYx)Cu2Oy solid solution

International Nuclear Information System (INIS)

Hong, Byungsun; Mason, T.O.

1993-01-01

By a combination of conventional physical property measurements and high temperature electrical property studies, the solid solution limit, transport parameters, and potential defect regimes of the Bi 2.1 Sr 1.9 (Ca 1 - x Y x )Cu 2 O y solid solution were established. A continuous solid solution extends to x = 0.7 or 0.8. The electrical properties indicate that the product of the hole density-of-states and mobility for semiconducting compositions is approximately an order of magnitude smaller than for the other p-type superconducting cuprates. A pronounced drop in hole concentration accompanies the tetragonal-to-orthorhombic transition at x = 0.5, where after superconductivity disappears. The electrical properties also indicate that a composition x ≥ 0.7 is the appropriate ''reference'' compound for the solid solution series. Upon doping this yttrium-rich insulating composition with calcium, holes are introduced. With increased calcium content (decreased yttrium content) the system exhibits several defect regimes reminiscent of the behavior in the La 2 - x AE x CuO 4 (AE = Sr or Ba) system. Oxygen defects (interstitial and vacancies) are believed to play an important role in the defect structure

Tunable electric properties of bilayer InSe with different interlayer distances and external electric field

Science.gov (United States)

Shang, Jimin; Pan, Longfei; Wang, Xiaoting; Li, Jingbo; Wei, Zhongming

2018-03-01

Using density functional theory we explore the band structure of bilayer Indium selenide (InSe), and we find that the van der Waals interaction has significant effects on the electric and optical properties. We then explore the tuning electronic properties by different interlayer distances and by an external vertical electric field. Our results demonstrate that the band gaps of bilayer InSe can be continuously tuned by different interlayer coupling. With decreasing interlayer distances, the tunable band gaps of bilayer decrease linearly, owing to the enhancement of the interlayer interaction. Additionally, the band structure of bilayer InSe under external vertical fields is discussed. The presence of a small external electric field can make a new spatial distribution of electron-hole pairs. A well separation based on the electrons and holes, localized in different layers can be obtained using this easy method. These properties of bilayer InSe indicates potential applications in designing new optoelectronic devices.

Electronic structure and thermoelectric transport properties of the golden Th2S3-type Ti2O3 under pressure

Directory of Open Access Journals (Sweden)

Bin Xu

2016-05-01

Full Text Available A lot of physical properties of Th2S3-type Ti2O3 have investigated experimentally, hence, we calculated electronic structure and thermoelectric transport properties by the first-principles calculation under pressure. The increase of the band gaps is very fast from 30GP to 35GP, which is mainly because of the rapid change of the lattice constants. The total density of states becomes smaller with increasing pressure, which shows that Seebeck coefficient gradually decreases. Two main peaks of Seebeck coefficients always decrease and shift to the high doping area with increasing temperature under pressure. The electrical conductivities always decrease with increasing temperature under pressure. The electrical conductivity can be improved by increasing pressure. Electronic thermal conductivity increases with increasing pressure. It is noted that the thermoelectric properties is reduced with increasing temperature.

Study of effective transport properties of fresh and aged gas diffusion layers

Science.gov (United States)

Bosomoiu, Magdalena; Tsotridis, Georgios; Bednarek, Tomasz

2015-07-01

Gas diffusion layers (GDLs) play an important role in proton exchange membrane fuel cells (PEMFCs) for the diffusion of reactant and the removal of product water. In the current study fresh and aged GDLs (Sigracet® GDL34BC) were investigated by X-ray computed tomography to obtain a representative 3D image of the real GDL structure. The examined GDL samples are taken from areas located under the flow channel and under the land. Additionally, a brand new Sigracet® GDL34BC was taken as a reference sample in order to find out the impact of fuel cell assembly on GDL. The produced 3D image data were used to calculate effective transport properties such as thermal and electrical conductivity, diffusivity, permeability and capillary pressure curves of the dry and partially saturated GDL. The simulation indicates flooding by product water occurs at contact angles lower than 125° depending on sample porosity. In addition, GDL anisotropy significantly affects the permeability as well as thermal and electrical conductivities. The calculated material bulk properties could be next used as input for CFD modelling of PEM fuel cells where GDL is usually assumed layer-like and homogeneous. Tensor material parameters allow to consider GDL anisotropy and lead to more realistic results.

Magnetic and electrical properties of ITER vacuum vessel steels

International Nuclear Information System (INIS)

Mergia, K.; Apostolopoulos, G.; Gjoka, M.; Niarchos, D.

2007-01-01

Full text of publication follows: Ferritic steel AISI 430 is a candidate material for the lTER vacuum vessel which will be used to limit the ripple in the toroidal magnetic field. The magnetic and electrical properties and their temperature dependence in the temperature range 300 - 900 K of AISI 430 ferritic stainless steels are presented. The temperature variation of the coercive field, remanence and saturation magnetization as well as electrical resistivity and the effect of annealing on these properties is discussed. (authors)

Hydrogen , Hybrid and Electric Propulsion in a Strategy for Sustainable Transport

DEFF Research Database (Denmark)

Jørgensen, Kaj

1998-01-01

Analysis of the scope for application of hydrogen and electric propulsion for improvement of the fuel cycle efficiency and introduction of renewable energy in the transport sector. The paper compares these fuels with each other as well as with other fuels (especially bio fuels) and outlines...... their individual roles in a strategy for sustainable transport. Finally, the fuels are compared to the present fuels....

Structure and magnetic transport properties of GdIn{sub 3−x}Mn{sub x} intermetallics

Energy Technology Data Exchange (ETDEWEB)

He, Qiang; Guo, Yongquan, E-mail: yqguo@ncepu.edu.cn; Liu, Hanyuan

2016-03-01

The crystal structures and magneto-transport properties of GdIn{sub 3−x}Mn{sub x} have been investigated using X-ray diffraction and magnetic and electric measurements. GdIn{sub 3−x}Mn{sub x} crystallize in cubic structure, and their lattice parameters tend to decrease with increasing Mn content due to the size effect at In site by Mn substitution for In. Mn doped GdIn{sub 3−x}Mn{sub x} order antiferromagnetically at low temperature. However, Mn doping into GdIn{sub 3} causes the decrease of Néel temperature due to the distortion of Gd(In,Mn){sub 3} tetrahedron formed by Gd at corners and (In,Mn) at face centers in unit cell. The resistivities of GdIn{sub 3−x}Mn{sub x} are going up with increasing Mn content. The electric phase transition is associated with the magnetic transition, and the magneto-transport follows electron–magnon scattering model in low temperature region and the Stoner spin fluctuation model in high temperature region, respectively. - Highlights: • Novel GdIn{sub 3−x}Mn{sub x} intermetallic compounds have been successfully prepared. • The lattice parameters tend to decrease with increasing Mn content. • GdIn{sub 3−x}Mn{sub x} orders antiferromagnetically at low temperature. • The strong correlation between the electric transport and magnetic state is observed.

Applications for Electrical Impedance Tomography (EIT) and Electrical Properties of the Human Body.

Science.gov (United States)

Lymperopoulos, Georgios; Lymperopoulos, Panagiotis; Alikari, Victoria; Dafogianni, Chrisoula; Zyga, Sofia; Margari, Nikoletta

2017-01-01

Electrical Impedance Tomography (EIT) is a promising application that displays changes in conductivity within a body. The basic principle of the method is the repeated measurement of surface voltages of a body, which are a result of rolling injection of known and small-volume sinusoidal AC current to the body through the electrodes attached to its surface. This method finds application in biomedicine, biology and geology. The objective of this paper is to present the applications of Electrical Impedance Tomography, along with the method's capabilities and limitations due to the electrical properties of the human body. For this purpose, investigation of existing literature has been conducted, using electronic databases, PubMed, Google Scholar and IEEE Xplore. In addition, there was a secondary research phase, using paper citations found during the first research phase. It should be noted that Electrical Impedance Tomography finds use in a plethora of medical applications, as the different tissues of the body have different conductivities and dielectric constants. Main applications of EIT include imaging of lung function, diagnosis of pulmonary embolism, detection of tumors in the chest area and diagnosis and distinction of ischemic and hemorrhagic stroke. EIT advantages include portability, low cost and safety, which the method provide, since it is a noninvasive imaging method that does not cause damage to the body. The main disadvantage of the method, which blocks its wider spread, appears in the image composition from the voltage measurements, which are conducted by electrodes placed on the periphery of the body, because the injected currents are affected nonlinearly by the general distribution of the electrical properties of the body. Furthermore, the complex impedance of the skin-electrode interface can be modelled by using a capacitor and two resistor, as a result of skin properties. In conclusion, Electrical Impedance Tomography is a promising method for the

Electrical properties of Egyptian natural graphite

International Nuclear Information System (INIS)

El-Shazly, O.; El-Wahidy, E.F.; Elanany, N.; Saad, N.A.

1992-06-01

The electrical properties of Egyptian natural graphite flakes, obtained from the graphite schists of Wadi Bent, Eastern Desert, were measured. The flakes were ground and compressed into pellets. The standard four probe dc method was used to measure the temperature dependence of the electric resistivity from room temperature down to 12 K. The transverse and longitudinal magnetoresistance were measured in the low magnetic field range at temperatures 300 K, 77 K and 12 K. The transverse magnetoresistance data was used to estimate the average mobility, assuming a simple two-band model. (author). 20 refs, 4 figs, 1 tab

i-CELIV technique for investigation of charge carriers transport properties

Energy Technology Data Exchange (ETDEWEB)

Važgėla, J., E-mail: julius.vazgela@ff.vu.lt; Genevičius, K.; Juška, G.

2016-10-20

The extraction of the injected charge carriers by linearly increasing voltage (i-CELIV) is a promising method for separate analysis of the holes and electrons transport properties in the bulk heterojunction layers. We are demonstrating how to establish the mobility dependence on the electric field and obtain more precise results by performing corrections in transit time by this technique. [6,6]-Phenyl C61 butyric acid methyl ester (PCBM) and poly[2,6-(4,4-bis-(2-ethylhexyl)-4H-cyclopenta [2,1-b;3,4-b′]dithiophene)-alt-4,7(2,1,3-benzothiadiazole)] (PCPDTBT) bulk heterojunctions with different blend ratios were experimentally tested with i-CELIV method. The hole and electron mobilities were found to be heavily imbalanced in the optimised 3:1 PCBM:PCPDTBT bulk heterojunction.

Electre III method in assessment of variants of integrated urban public transport system in Cracow

Directory of Open Access Journals (Sweden)

Katarzyna SOLECKA

2014-12-01

Full Text Available There is a lot of methods which are currently used for assessment of urban public transport system development and operation e.g. economic analysis, mostly Cost-Benefit Analysis – CBA, Cost-Effectiveness Analysis - CEA, hybrid methods, measurement methods (survey e.g. among passengers and measurement of traffic volume, vehicles capacity etc., and multicriteria decision aiding methods (multicriteria analysis. The main aim of multicriteria analysis is the choice of the most desirable solution from among alternative variants according to different criteria which are difficult to compare against one another. There are several multicriteria methods for assessment of urban public transport system development and operation, e.g. AHP, ANP, Electre, Promethee, Oreste. The paper presents an application of one of the most popular variant ranking methods – Electre III method. The algorithm of Electre III method usage is presented in detail and then its application for assessment of variants of urban public transport system integration in Cracow is shown. The final ranking of eight variants of integration of urban public transport system in Cracow (from the best to the worst variant was drawn up with the application of the Electre III method. For assessment purposes 10 criteria were adopted: economical, technical, environmental, and social; they form a consistent criteria family. The problem was analyzed with taking into account different points of view: city authorities, public transport operators, city units responsible for transport management, passengers and others users. Separate models of preferences for all stakeholders were created.

Transport and magnetic properties of new heavy-fermion antiferromagnet YbNi{sub 3}Al{sub 9}

Energy Technology Data Exchange (ETDEWEB)

Ohara, S; Yamashita, T; Mori, Y; Sakamoto, I, E-mail: ohara.shigeo@nitech.ac.jp [Department of Engineering Physics, Electronics and Mechanics, Graduate School of Engineering, Nagoya Institute of Technology, Nagoya 466-8555 (Japan)

2011-01-01

We have synthesized a new Yb-based Kondo-lattice compound YbNi{sub 3}Al{sub 9}. This compound crystallizes in a trigonal ErNi{sub 3}Al{sub 9}-type structure (space group R32), in which the Yb-ion is arranged in a two-dimensional honey-comb lattice perpendicular to the c-axis. We report the first measurements of electrical resistivity and magnetization for single-crystalline samples of YbNi{sub 3}Al{sub 9}. The electrical resistivity of YbNi{sub 3}Al{sub 9} is characteristic of the typical properties of heavy-fermion antiferromagnets with a Neel temperature of T{sub N} = 3.4 K. The transport and magnetic properties exhibit large anisotropy in the low-temperature region owing to an interplay among the crystalline-electric-field effect, the Ruderman-Kittel-Kasuya-Yoshida interaction, and the Kondo effect. Below T{sub N}, the metamagnetic transition is observed at a very low magnetic field of around 1 kOe with the field applied along the a-axis. The magnetic structure of YbNi{sub 3}Al{sub 9} is highly sensitive to the applied magnetic field.

Charge transport properties of metal/metal-phthalocyanine/n-Si structures

Energy Technology Data Exchange (ETDEWEB)

Hussain, Afzal

2010-12-16

In present work the charge transport properties of metal/metal-phthalocyanine/n-Si structures with low (N{sub D} = 4 x 10{sup 14} cm{sup -3}), medium (N{sub D}=1 x 10{sup 16} cm{sup -3}) and high (N{sub D}=2 x 10{sup 19} cm{sup -3}) doped n-Si as injecting electrode and the effect of air exposure of the vacuum evaporated metal-phthalocyanine film in these structures is investigated. The results obtained through temperature dependent electrical characterizations of the structures suggest that in terms of dominant conduction mechanism in the corresponding devices Schottky-type conduction mechanism dominates the charge transport in low-bias region of these devices up to 0.8 V, 0.302 V and 0.15 V in case of low, medium and high doped n-Silicon devices. For higher voltages, in each case of devices, the space-charge-limited conduction, controlled by exponential trap distribution, is found to dominate the charge transport properties of the devices. The interface density of states at the CuPc/n-Si interface of the devices are found to be lower in case of lower work function difference at the CuPc/n-Si interface of the devices. The results also suggest that the work function difference at the CuPc/n-Si interface of these devices causes charge transfer at the interface and these phenomena results in formation of interface dipole. The width of the Schottky depletion region at the CuPc/n-Si interface of these devices is found to be higher with higher work function difference at the interface. The investigation of charge transport properties of Al/ZnPc/medium n-Si and Au/ZnPc/ medium n-Si devices suggest that the Schottky depletion region formed at the ZnPc/n-Si interface of these devices determines the charge transport in the low-bias region of both the devices. Therefore, the Schottky-type (injection limited) and the space-charge-limited (bulk limited) conduction are observed in the low and the high bias regions of these devices, respectively. The determined width of the

Electrically tunable transport and high-frequency dynamics in antiferromagnetic S r3I r2O7

Science.gov (United States)

Seinige, Heidi; Williamson, Morgan; Shen, Shida; Wang, Cheng; Cao, Gang; Zhou, Jianshi; Goodenough, John B.; Tsoi, Maxim

2016-12-01

We report dc and high-frequency transport properties of antiferromagnetic S r3I r2O7 . Temperature-dependent resistivity measurements show that the activation energy of this material can be tuned by an applied dc electrical bias. The latter allows for continuous variations in the sample resistivity of as much as 50% followed by a reversible resistive switching at higher biases. Such a switching is of high interest for antiferromagnetic applications in high-speed memory devices. Interestingly, we found the switching behavior to be strongly affected by a high-frequency (microwave) current applied to the sample. The microwaves at 3-7 GHz suppress the dc switching and produce resonancelike features that we tentatively associated with the dissipationless magnonics recently predicted to occur in antiferromagnetic insulators subject to ac electric fields. We have characterized the effects of microwave irradiation on electronic transport in S r3I r2O7 as a function of microwave frequency and power, strength and direction of external magnetic field, strength and polarity of applied dc bias, and temperature. Our observations support the potential of antiferromagnetic materials for high-speed/high-frequency spintronic applications.

Electrical transport in GaN and InN nanowires; Elektrischer Transport in GaN- und InN-Nanodraehten

Energy Technology Data Exchange (ETDEWEB)

Richter, Thomas Fabian

2008-12-19

This thesis discusses the analysis of the electrical transport in GaN and InN nanowires at room temperature and deep temperatures. From those measurements two different transport models for those two in matter of the band banding completely different materials have been found. In the investigation of the GaN nanowires the main focus was the electrical transport in dependence of the diameter and the n-doping. With the use of IV-measurements on those MBE grown nanowires with different diameters at dark and under UV illumination as well as the decay of the persistent photocurrent, it was possible to find an for GaN untypical behaviour. The electrical transport in those wires is extremely diameter dependent. The dark current shows space charged limited current. With the help of those cognitions a diameter dependent transport model could be found. The transport phenomena in those wires is based on the diameter depending band bending at the edge of the wires caused by the Fermi level pinning inside the forbidden band. This model can be fit to the data with the three parameter doping, fermi level pinning and wire diameter. On the base of those effects a method to determine the doping concentration inside those wires without field effect measurements and contact resistance has been developed. The defect structure inside those wires has been analysed with the help of spectral photoluminescence measurements. Here several defect bands have been found and it was possible with help of several contacts on one single wire to determine different defect regions along the wire and to explain them by the lattice mismatch between nanowire and substrate. Further temperature depending measurements and investigations on Schottky contacted wires as well as on GaN wires with AlN tunnel structures complete the work on GaN. The electrical characterisation on a large scale of undoped and doped InN nanowires shows linear growth of the dark current with the diameter up to wires of around 100 nm

Electrical properties of phosphate glasses

International Nuclear Information System (INIS)

Mogus-Milankovic, A; Santic, A; Reis, S T; Day, D E

2009-01-01

Investigation of the electrical properties of phosphate glasses where transition metal oxide such as iron oxide is the network former and network modifier is presented. Phosphate glasses containing iron are electronically conducting glasses where the polaronic conduction is due to the electron hopping from low to high iron valence state. The identification of structural defects caused by ion/polaron migration, the analysis of dipolar states and electrical conductivity in iron phosphate glasses containing various alkali and mixed alkali ions was performed on the basis of the impedance spectroscopy (IS). The changes in electrical conductivity from as-quenched phosphate glass to fully crystallized glass (glass-ceramics) by IS are analyzed. A change in the characteristic features of IS follows the changes in glass and crystallized glass network. Using IS, the contribution of glass matrix, crystallized grains and grain boundary to the total electrical conductivity for iron phosphate glasses was analyzed. It was shown that decrease in conductivity is caused by discontinuities in the conduction pathways as a result of the disruption of crystalline network where two or more crystalline phases are formed. Also, phosphate-based glasses offer a unique range of biomaterials, as they form direct chemical bonding with hard/soft tissue. The surface charges of bioactive glasses are recognized to be the most important factors in determining biological responses. The improved bioactivity of the bioactive glasses as a result of the effects of the surface charges generated by electrical polarization is discussed.

Effects of radial electrical field on neoclassical transport in tokamaks

International Nuclear Information System (INIS)

Wang Zhongtian; Le Clair, G.

1996-07-01

Neoclassical transport theory for tokamaks in presence of a radial electrical field with shear is developed using Hamiltonian formalism. Diffusion coefficients are derived in both plateau regime including a large electric field and banana regime including the squeezing factor which can greatly affect diffusion at the plasma edge. The scaling on squeezing factor is different from the one given by Shaing and Hazeltine. Rotation speeds are calculated in the scrape-off region. They are in good agreement with measurements on TdeV Tokamak. (2 figs.)

Comparison of all-electric secondary power systems for civil subsonic transports

Science.gov (United States)

Renz, David D.

1992-01-01

Three separate studies have shown operational, weight, and cost advantages for commercial subsonic transport aircraft using an all-electric secondary power system. The first study in 1982 showed that all-electric secondary power systems produced the second largest benefit compared to four other technology upgrades. The second study in 1985 showed a 10 percent weight and fuel savings using an all-electric high frequency (20 kHz) secondary power system. The last study in 1991 showed a 2 percent weight savings using today's technology (400 Hz) in an all-electric secondary power system. This paper will compare the 20 kHz and 400 Hz studies, analyze the 2 to 10 percent difference in weight savings and comment on the common benefits of the all-electric secondary power system.

Ab initio calculation of transport properties between PbSe quantum dots facets with iodide ligands

Science.gov (United States)

Wang, B.; Patterson, R.; Chen, W.; Zhang, Z.; Yang, J.; Huang, S.; Shrestha, S.; Conibeer, G.

2018-01-01

The transport properties between Lead Selenide (PbSe) quantum dots decorated with iodide ligands has been studied using density functional theory (DFT). Quantum conductance at each selected energy levels has been calculated along with total density of states and projected density of states. The DFT calculation is carried on using a grid-based planar augmented wave (GPAW) code incorporated with the linear combination of atomic orbital (LCAO) mode and Perdew Burke Ernzerhof (PBE) exchange-correlation functional. Three iodide ligand attached low index facets including (001), (011), (111) are investigated in this work. P-orbital of iodide ligand majorly contributes to density of state (DOS) at near top valence band resulting a significant quantum conductance, whereas DOS of Pb p-orbital shows minor influence. Various values of quantum conductance observed along different planes are possibly reasoned from a combined effect electrical field over topmost surface and total distance between adjacent facets. Ligands attached to (001) and (011) planes possess similar bond length whereas it is significantly shortened in (111) plane, whereas transport between (011) has an overall low value due to newly formed electric field. On the other hand, (111) plane with a net surface dipole perpendicular to surface layers leading to stronger electron coupling suggests an apparent increase of transport probability. Apart from previously mentioned, the maximum transport energy levels located several eVs (1 2 eVs) from the edge of valence band top.

ELECTRICAL AND THERMODYNAMIC PROPERTIES OF A COLLAGEN SOLUTION

Directory of Open Access Journals (Sweden)

Jaromír Štancl

2017-06-01

Full Text Available This paper focuses on measurements of the electrical properties, the specific heat capacity and the thermal conductivity of a collagen solution (7.19% mass fraction of native bovine collagen in water. The results of our experiments show that specific electrical conductivity of collagen solution is strongly dependent on temperature. The transition region of collagen to gelatin has been observed from the measured temperature dependence of specific electrical conductivity, and has been confirmed by specific heat capacity measurements by a differential scanning calorimetry.

Proceedings of the Prop'Elec 2000 colloquium. Advances of electric drive in urban transportation systems; Actes du colloque Prop'Elec 2000. Progres de la traction electrique dans les transports urbains

Energy Technology Data Exchange (ETDEWEB)

NONE

2000-07-01

This document is the proceedings of Prop'Elec 2000 colloquium on the advances in electric power drive in urban transportation systems. The colloquium comprises 5 sessions dealing with: 1 - public collective electric-powered transportation system: synthesis of urban guided systems (C. Soulas, INRETS), the fast travelator (A. Cote, RATP), the power supply system of METEOR automatic underground railway (P. Lagrange, W. Seiler, RATP); 2 - electrical drive in urban transportation systems: start-up of a thermal engine with super-capacitors (D. Bouquain (CREEBEL), H. Gualous, A. Djerdir, A. Berthon, J.M. Kauffmann (L2ES, IGE)), The LEV (light weight electric vehicle) project in Mendrisio (U. Schwegler, LEV/Suisse), prototype of electrical bike that use a wheel-engine (C. Espanet, F. Gustin, J.M. Kauffmann (IGE), S. Robert, M. Karmous (EICN)), TWIL: a new generation of small electrical bikes (E. Escallot, T. Bontems (EPMI)), thermal and magnetic analysis of a rectilinear movement actuator (J.C. Vannier, M. Kadiri (SUPELEC)), torque undulation and vibrations in automobile electrical drives (A.L. Bui-Van (Renault), A. Fonseca (LEG)); 3 - collective electric-powered transportation systems: STARS: autonomous transportation system with flywheel charging at the station (P. Gibard (Alstom Transport), K. Abuda, J.M. Vinassa (IXL Bordeaux)), Translhor tramway: presentation of the drive system (L. Verdier, LHOR); 4 - electric-powered and hybrid vehicles: batteries for electric-powered vehicles (J.F. Fauvarque, CNAM), Li-ion batteries and their application in automotive industry (T. Faugeras, SAFT), optimized drive systems for electric-powered vehicles (J. Saint-Michel, Leroy Somer), the Citroen Xsara Dynactive (S. Derou, PSA), 5 - electric-powered and hybrid vehicles: the electrical car in tomorrows' city (M. Parent, INRIA), the market of electric-powered vehicles in France and Europe (M. Valet, PSA). (J.S.)

Electrical transport across nanometric SrTiO3 and BaTiO3 barriers in conducting/insulator/conducting junctions

Science.gov (United States)

Navarro, H.; Sirena, M.; González Sutter, J.; Troiani, H. E.; del Corro, P. G.; Granell, P.; Golmar, F.; Haberkorn, N.

2018-01-01

We report the electrical transport properties of conducting/insulator/conducting heterostructures by studying current-voltage IV curves at room temperature. The measurements were obtained on tunnel junctions with different areas (900, 400 and 100 μm2) using a conducting atomic force microscope. Trilayers with GdBa2Cu3O7 (GBCO) as the bottom electrode, SrTiO3 or BaTiO3 (thicknesses between 1.6 and 4 nm) as the insulator barrier, and GBCO or Nb as the top electrode were grown by DC sputtering on (100) SrTiO3 substrates For SrTiO3 and BaTiO3 barriers, asymmetric IV curves at positive and negative polarization can be obtained using electrodes with different work function. In addition, hysteretic IV curves are obtained for BaTiO3 barriers, which can be ascribed to a combined effect of the FE reversal switching polarization and an oxygen vacancy migration. For GBCO/BaTiO3/GBCO heterostructures, the IV curves correspond to that expected for asymmetric interfaces, which indicates that the disorder affects differently the properties at the bottom and top interfaces. Our results show the role of the interface disorder on the electrical transport of conducting/insulator/conduction heterostructures, which is relevant for different applications, going from resistive switching memories (at room temperature) to Josephson junctions (at low temperatures).

Electric-Field Control of Interfering Transport Pathways in a Single-Molecule Anthraquinone Transistor

NARCIS (Netherlands)

Koole, Max; Thijssen, Jos M.; Valkenier, Hennie; Hummelen, Jan C.; van der Zant, Herre S. J.

It is understood that molecular conjugation plays an important role in charge transport through single-molecule junctions. Here, we investigate electron transport through an anthraquinone based single-molecule three-terminal device. With the use of an electric-field induced by a gate electrode, the

Graphene and electric transport properties in graphene-superconductor interfaces

OpenAIRE

Manjarrés, Diego; Gómez, Shirley; Herrera, William

2012-01-01

El grafeno es una estructura bidimensional de carbono que tiene propiedades electrónicas que no son usuales y  donde los electrones son descritos por la ecuación de Dirac. Este material permite establecer una analogía entre la física de partículas y la materia condensada. La obtención del grafeno hace pocos años ha incentivado una gran cantidad de trabajos experimentales y teóricos con el propósito de poder entender y manipular sus propiedades. Actualmente se han investigado diferentes juntur...

Fabrication and study of the electrical properties of PbO/Fe based ...

African Journals Online (AJOL)

Fabrication and study of the electrical properties of PbO/Fe based composite ... is aimed at fabrication and study of the electrical properties of cermets resistor, ... obtained and this largely depended on the composition of the materials used.

Effect of microstructure on the electronic transport properties of epitaxial CaRuO{sub 3} thin films

Energy Technology Data Exchange (ETDEWEB)

Daptary, Gopi Nath; Sow, Chanchal; Sarkar, Suman; Chiniwar, Santosh; Kumar, P.S. Anil [Department of Physics, Indian Institute of Science, Bangalore 560012 (India); Sil, Anomitra [Center For Nano Science And Engineering, Indian Institute of Science, Bangalore 560012 (India); Bid, Aveek, E-mail: aveek.bid@physics.iisc.ernet.in [Department of Physics, Indian Institute of Science, Bangalore 560012 (India)

2017-04-15

We have carried out extensive comparative studies of the structural and transport properties of CaRuO{sub 3} thin films grown under various oxygen pressure. We find that the preferred orientation and surface roughness of the films are strongly affected by the oxygen partial pressure during growth. This in turn affects the electrical and magnetic properties of the films. Films grown under high oxygen pressure have the least surface roughness and show transport characteristics of a good metal down to the lowest temperature measured. On the other hand, films grown under low oxygen pressures have high degree of surface roughness and show signatures of ferromagnetism. We could verify that the low frequency resistance fluctuations (noise) in these films arise due to thermally activated fluctuations of local defects and that the defect density matches with the level of disorder seen in the films through structural characterizations.

Conceptual design of hybrid-electric transport aircraft

Science.gov (United States)

Pornet, C.; Isikveren, A. T.

2015-11-01

The European Flightpath 2050 and corresponding Strategic Research and Innovation Agenda (SRIA) as well as the NASA Environmentally Responsible Aviation N+ series have elaborated aggressive emissions and external noise reduction targets according to chronological waypoints. In order to deliver ultra-low or even zero in-flight emissions levels, there exists an increasing amount of international research and development emphasis on electrification of the propulsion and power systems of aircraft. Since the late 1990s, a series of experimental and a host of burgeouning commercial activities for fixed-wing aviation have focused on glider, ultra-light and light-sport airplane, and this is proving to serve as a cornerstone for more ambitious transport aircraft design and integration technical approaches. The introduction of hybrid-electric technology has dramatically expanded the design space and the full-potential of these technologies will be drawn through synergetic, tightly-coupled morphological and systems integration emphasizing propulsion - as exemplified by the potential afforded by distributed propulsion solutions. With the aim of expanding upon the current repository of knowledge associated with hybrid-electric propulsion systems a quad-fan arranged narrow-body transport aircraft equipped with two advanced Geared-Turbofans (GTF) and two Electrical Fans (EF) in an under-wing podded installation is presented in this technical article. The assessment and implications of an increasing Degree-of-Hybridization for Useful Power (HP,USE) on the overall sizing, performance as well as flight technique optimization of fuel-battery hybrid-electric aircraft is addressed herein. The integrated performance of the concept was analyzed in terms of potential block fuel burn reduction and change in vehicular efficiency in comparison to a suitably projected conventional aircraft employing GTF-only propulsion targeting year 2035. Results showed that by increasing HP,USE, significant

Spin dynamics, electronic, and thermal transport properties of two-dimensional CrPS4 single crystal

Science.gov (United States)

Pei, Q. L.; Luo, X.; Lin, G. T.; Song, J. Y.; Hu, L.; Zou, Y. M.; Yu, L.; Tong, W.; Song, W. H.; Lu, W. J.; Sun, Y. P.

2016-01-01

2-Dimensional (2D) CrPS4 single crystals have been grown by the chemical vapor transport method. The crystallographic, magnetic, electronic, and thermal transport properties of the single crystals were investigated by the room-temperature X-ray diffraction, electrical resistivity ρ(T), specific heat CP(T), and the electronic spin response (ESR) measurements. CrPS4 crystals crystallize into a monoclinic structure. The electrical resistivity ρ(T) shows a semiconducting behavior with an energy gap Ea = 0.166 eV. The antiferromagnetic transition temperature is about TN = 36 K. The spin flipping induced by the applied magnetic field is observed along the c axis. The magnetic phase diagram of CrPS4 single crystal has been discussed. The extracted magnetic entropy at TN is about 10.8 J/mol K, which is consistent with the theoretical value R ln(2S + 1) for S = 3/2 of the Cr3+ ion. Based on the mean-field theory, the magnetic exchange constants J1 and Jc corresponding to the interactions of the intralayer and between layers are about 0.143 meV and -0.955 meV are obtained based on the fitting of the susceptibility above TN, which agree with the results obtained from the ESR measurements. With the help of the strain for tuning the magnetic properties, monolayer CrPS4 may be a promising candidate to explore 2D magnetic semiconductors.

Ion confinement and transport in a toroidal plasma with externally imposed radial electric fields

Science.gov (United States)

Roth, J. R.; Krawczonek, W. M.; Powers, E. J.; Kim, Y. C.; Hong, H. Y.

1979-01-01

Strong electric fields were imposed along the minor radius of the toroidal plasma by biasing it with electrodes maintained at kilovolt potentials. Coherent, low-frequency disturbances characteristic of various magnetohydrodynamic instabilities were absent in the high-density, well-confined regime. High, direct-current radial electric fields with magnitudes up to 135 volts per centimeter penetrated inward to at least one-half the plasma radius. When the electric field pointed radially toward, the ion transport was inward against a strong local density gradient; and the plasma density and confinement time were significantly enhanced. The radial transport along the electric field appeared to be consistent with fluctuation-induced transport. With negative electrode polarity the particle confinement was consistent with a balance of two processes: a radial infusion of ions, in those sectors of the plasma not containing electrodes, that resulted from the radially inward fields; and ion losses to the electrodes, each of the which acted as a sink and drew ions out of the plasma. A simple model of particle confinement was proposed in which the particle confinement time is proportional to the plasma volume. The scaling predicted by this model was consistent with experimental measurements.

Microstructure and opto-electric properties of Cu/ITO thin films

International Nuclear Information System (INIS)

Wang Xian; Li Junlei; Shi Shiwei; Song Xueping; Cui Jingbiao; Sun Zhaoqi

2012-01-01

Highlights: ► We prepared Cu/ITO films with different Cu layer thickness. ► We analyzed the relation between opto-electric properties and roughness of the films. ► The Cu-16.1 nm/ITO film shows excellent optical and electric properties. ► Cu/ITO films have great application prospects in new-type transflective displays. - Abstract: Cu/ITO thin films were deposited on glass and silicon substrates by DC and RF magnetron sputtering at room temperature. X-ray diffraction results showed that the films were amorphous. Both of SEM images and 3D Profilometer images indicated that the surface morphology of the ITO films had been affected by the Cu layer. The optical and electric properties of the Cu/ITO films changed significantly with the variation of Cu layer thickness. Cu-5.4 nm/ITO film exhibited the highest optical transmittance of 62.9% at 550 nm and the lowest sheet resistance of 96 Ω/□, whereas Cu-16.1 nm/ITO film showed the highest average reflectance of 24.0% and the lowest resistance of 27.4 Ω/□. Based on our analysis, it was evaluated that Cu layer had an important effect on the electrical and optical properties of ITO thin films.

The potential for western Canada to become a leader in electrically powered land transport

Energy Technology Data Exchange (ETDEWEB)

Perl, A.; Gilbert, R. [Simon Fraser Univ., Burnaby, BC (Canada)

2010-07-01

Canada's western provinces are among the most oil-intensive jurisdictions in the world. Per capita consumption in 2007 was 70 percent higher than that of eastern Canada. While western Canada will be buffered as a producer of oil, predicted swings in oil prices may disrupt the fiscal capacity of producer provinces. The price of crude oil in western Canada is the same price established in world markets. This paper examined some of the opportunities available for western Canada to move away from oil consumption by becoming a leader in electric traction. Methods of replacing oil-based transportation with the use of electric vehicles were discussed. Western Canada's capacity to produce electricity from renewable resources was evaluated. Economic opportunities related to the electrification of land transport were also examined. The report concluded by stating that a clear vision and policy framework for supporting new technologies for surface transport across western Canada are needed. 72 refs., 4 figs.

The potential for western Canada to become a leader in electrically powered land transport

International Nuclear Information System (INIS)

Perl, A.; Gilbert, R.

2010-01-01

Canada's western provinces are among the most oil-intensive jurisdictions in the world. Per capita consumption in 2007 was 70 percent higher than that of eastern Canada. While western Canada will be buffered as a producer of oil, predicted swings in oil prices may disrupt the fiscal capacity of producer provinces. The price of crude oil in western Canada is the same price established in world markets. This paper examined some of the opportunities available for western Canada to move away from oil consumption by becoming a leader in electric traction. Methods of replacing oil-based transportation with the use of electric vehicles were discussed. Western Canada's capacity to produce electricity from renewable resources was evaluated. Economic opportunities related to the electrification of land transport were also examined. The report concluded by stating that a clear vision and policy framework for supporting new technologies for surface transport across western Canada are needed. 72 refs., 4 figs.

Bond length and electric current oscillation of long linear carbon chains: Density functional theory, MpB model, and quantum spin transport studies

International Nuclear Information System (INIS)

Oeiras, R. Y.; Silva, E. Z. da

2014-01-01

Carbon linear atomic chains attached to graphene have experimentally been produced. Motivated by these results, we study the nature of the carbon bonds in these nanowires and how it affects their electrical properties. In the present study we investigate chains with different numbers of atoms and we observe that nanowires with odd number of atoms present a distinct behavior than the ones with even numbers. Using graphene nanoribbons as leads, we identify differences in the quantum transport of the chains with the consequence that even and odd numbered chains have low and high electrical conduction, respectively. We also noted a dependence of current with the wire size. We study this unexpected behavior using a combination of first principles calculations and simple models based on chemical bond theory. From our studies, the electrons of carbon nanowires present a quasi-free electron behavior and this explains qualitatively the high electrical conduction and the bond lengths with unexpected values for the case of odd nanowires. Our study also allows the understanding of the electric conduction dependence with the number of atoms and their parity in the chain. In the case of odd number chains a proposed π-bond (MpB) model describes unsaturated carbons that introduce a mobile π-bond that changes dramatically the structure and transport properties of these wires. Our results indicate that the nature of bonds plays the main role in the oscillation of quantum electrical conduction for chains with even and odd number of atoms and also that nanowires bonded to graphene nanoribbons behave as a quasi-free electron system, suggesting that this behavior is general and it could also remain if the chains are bonded to other materials

Electronic contributions to the transport properties and specific heat of solid UO2: an empirical, self-consistent analysis

International Nuclear Information System (INIS)

Hyland, G.J.; Ralph, J.

1982-07-01

From an empirical, self-consistent analysis of new high temperature data on the thermo-electric Seebeck coefficient and d.c. electrical conductivity, the value of the free energy controlling the equilibrium of the thermally induced reaction, 2U 4+ reversible U 3+ + U 5+ is determined (treating the U 3+ and U 5+ as small polarons) and used to calculate the contribution of the process to the high temperature thermal conductivity and specific heat of UO 2 . It is found that the transport properties can be completely accounted for in this way, but not the anomalous rise in specific heat - the origin of which remains obscure. (U.K.)

Formation and electrical transport properties of pentacene nanorod crystal

International Nuclear Information System (INIS)

Akai-Kasaya, M; Ohmori, C; Kawanishi, T; Nashiki, M; Saito, A; Kuwahara, Y; Aono, M

2010-01-01

The monophasic formation of an uncharted pentacene crystal, the pentacene nanorod, has been investigated. The restricted formation of the pentacene nanorod on a bare mica surface reveals a peculiar surface catalytic crystal growth mode of the pentacene. We demonstrated the charge transport measurements through a single pentacene nanorod and analyzed the data using a periodic hopping conduction model. The results revealed that the pentacene nanorod has a periodic conductive node within their one-dimensional crystal.

Formation and electrical transport properties of pentacene nanorod crystal.

Science.gov (United States)

Akai-Kasaya, M; Ohmori, C; Kawanishi, T; Nashiki, M; Saito, A; Aono, M; Kuwahara, Y

2010-09-10

The monophasic formation of an uncharted pentacene crystal, the pentacene nanorod, has been investigated. The restricted formation of the pentacene nanorod on a bare mica surface reveals a peculiar surface catalytic crystal growth mode of the pentacene. We demonstrated the charge transport measurements through a single pentacene nanorod and analyzed the data using a periodic hopping conduction model. The results revealed that the pentacene nanorod has a periodic conductive node within their one-dimensional crystal.

Effect of Ar bombardment on the electrical and optical properties of ...

Indian Academy of Sciences (India)

The influence of low-energy Ar ion beam irradiation on both electrical and optical properties of low-density polyethylene (LDPE) films is presented. The polymer films were bombarded with 320 keV Ar ions with fuences up to 1 × 10 15 cm − 2 . Electrical properties of LDPE films were measured and the effect of ion ...

An improved FEM model for computing transport AC loss in coils made of RABiTS YBCO coated conductors for electric machines

International Nuclear Information System (INIS)

Ainslie, Mark D; Yuan Weijia; Flack, Timothy J; Coombs, Timothy A; Rodriguez-Zermeno, Victor M; Hong Zhiyong

2011-01-01

AC loss can be a significant problem for any applications that utilize or produce an AC current or magnetic field, such as an electric machine. The authors investigate the electromagnetic properties of high temperature superconductors with a particular focus on the AC loss in superconducting coils made from YBCO coated conductors for use in an all-superconducting electric machine. This paper presents an improved 2D finite element model for the cross-section of such coils, based on the H formulation. The model is used to calculate the transport AC loss of a racetrack-shaped coil using constant and magnetic field-dependent critical current densities, and the inclusion and exclusion of a magnetic substrate, as found in RABiTS (rolling-assisted biaxially textured substrate) YBCO coated conductors. The coil model is based on the superconducting stator coils used in the University of Cambridge EPEC Superconductivity Group's all-superconducting permanent magnet synchronous motor design. To validate the modeling results, the transport AC loss of a stator coil is measured using an electrical method based on inductive compensation by means of a variable mutual inductance. Finally, the implications of the findings on the performance of the motor are discussed.

An improved FEM model for computing transport AC loss in coils made of RABiTS YBCO coated conductors for electric machines

Energy Technology Data Exchange (ETDEWEB)

Ainslie, Mark D; Yuan Weijia; Flack, Timothy J; Coombs, Timothy A [Department of Engineering, University of Cambridge, 9 J J Thomson Avenue, Cambridge CB3 0FA (United Kingdom); Rodriguez-Zermeno, Victor M [Department of Mathematics, Technical University of Denmark, Kongens Lyngby 2800 (Denmark); Hong Zhiyong, E-mail: mda36@cam.ac.uk [School of Electronic, Information and Electrical Engineering, Shanghai Jiao Tong University, Shanghai (China)

2011-04-15

AC loss can be a significant problem for any applications that utilize or produce an AC current or magnetic field, such as an electric machine. The authors investigate the electromagnetic properties of high temperature superconductors with a particular focus on the AC loss in superconducting coils made from YBCO coated conductors for use in an all-superconducting electric machine. This paper presents an improved 2D finite element model for the cross-section of such coils, based on the H formulation. The model is used to calculate the transport AC loss of a racetrack-shaped coil using constant and magnetic field-dependent critical current densities, and the inclusion and exclusion of a magnetic substrate, as found in RABiTS (rolling-assisted biaxially textured substrate) YBCO coated conductors. The coil model is based on the superconducting stator coils used in the University of Cambridge EPEC Superconductivity Group's all-superconducting permanent magnet synchronous motor design. To validate the modeling results, the transport AC loss of a stator coil is measured using an electrical method based on inductive compensation by means of a variable mutual inductance. Finally, the implications of the findings on the performance of the motor are discussed.

Biological and electrical properties of biosynthesized silver

Indian Academy of Sciences (India)

Biological and electrical properties of biosynthesized silver nanoparticles. Madhulika ... Abstract. In this work, silver nanoparticles (AgNPs) were synthesized biochemically at room temperature using aqueous extract of rhizome of Rheum australe plant. ... The obtained results may have potential applications as sensors.

A network model for electrical transport in sea ice

International Nuclear Information System (INIS)

Zhu, J.; Golden, K.M.; Gully, A.; Sampson, C.

2010-01-01

Monitoring the thickness of sea ice is an important tool in assessing the impact of global warming on Earth's polar regions, and most methods of measuring ice thickness depend on detailed knowledge of its electrical properties. We develop a network model for the electrical conductivity of sea ice, which incorporates statistical measurements of the brine microstructure. The numerical simulations are in close agreement with direct measurements we made in Antarctica on the vertical conductivity of first year sea ice.

Assesment of influncing factors on mechanical and electrical properties of Al/Cu joints

Science.gov (United States)

Selvaraj, R. Meby; Hynes, N. Rajesh Jesudoss

2018-05-01

Joining of dissimilar materials opens up challenging opportunities in todays technology. Al/Cu weldments are used in applications that demands corrosion resistance, thermal and electrical conducting properties. In dissimilar joining mechanical and thermal properties result in large stress gradients during heating. The Al-Cu joints are lighter, cheaper and have conductivity equal to copper alloy. The main scope of this study is to assess the influencing factors of Al/Cu joints in mechanical and electrical properties. It includes the influence of the dilution between the base metals, influence of physical properties, influence of welding parameters, influence of filler metal, influence of heat treatment, and influence of electrical properties

Magnetically induced electrical transport and dielectric properties of 3d transition elemental substitution at the Mn-site in Nd0.67Ba0.33MnO3 manganites

Science.gov (United States)

Sudakshina, B.; Arun, B.; Chandrasekhar, K. Devi; Yang, H. D.; Vasundhara, M.

2018-05-01

We have investigated the temperature dependence of electrical transport and dielectric properties along with magnetoresistance and magneto dielectric behavior in Nd0.67Ba0.33Mn0.9TR0.1O3 (TR= Cr, Fe, Co, Ni, Cu) manganites. All the compounds crystallized into an orthorhombic structure with Imma space group. Nd0.67Ba0.33MnO3 shows insulating to metallic behavior at intermediate temperatures, but, with the substitution of transitional elements it shows insulating in nature, down to lowest temperature measured for all the compounds. Dielectric measurement shows the intrinsic behavior of these lossy materials. A large value of magneto resistance is obtained for all the compounds and considerable amount of magneto-dielectric effect is shown for all the substituted compounds at lower temperatures.

Modelling the role of intrinsic electric fields in microtubules as an additional control mechanism of bi-directional intracellular transport.

Science.gov (United States)

Sataric, M V; Budinski-Petkovic, L; Loncarevic, I; Tuszynski, J A

2008-01-01

Active transport is essential for cellular function, while impaired transport has been linked to diseases such as neuronal degeneration. Much long distance transport in cells uses opposite polarity molecular motors of the kinesin and dynein families to move cargos along microtubules. It is clear that many types of cargo are moved by both sets of motors, and frequently in a reverse direction. The general question of how the direction of transport is regulated is still open. The mechanism of the cell's differential control of diverse cargos within the same cytoplasmic background is still unclear as is the answer to the question how endosomes and mitochondria move to different locations within the same cell. To answer these questions we postulate the existence of a local signaling mechanism used by the cell to specifically control different cargos. In particular, we propose an additional physical mechanism that works through the use of constant and alternating intrinsic (endogenous) electric fields as a means of controlling the speed and direction of microtubule-based transport. A specific model is proposed and analyzed in this paper. The model involves the rotational degrees of freedom of the C-termini of tubulin, their interactions and the coupling between elastic and dielectric degrees of freedom. Viscosity of the solution is also included and the resultant equation of motion is found as a nonlinear elliptic equation with dissipation. A particular analytical solution of this equation is obtained in the form of a kink whose properties are analyzed. It is concluded that this solution can be modulated by the presence of electric fields and hence may correspond to the observed behavior of motor protein transport along microtubules.

The Elusive Memristor: Properties of Basic Electrical Circuits

Science.gov (United States)

Joglekar, Yogesh N.; Wolf, Stephen J.

2009-01-01

We present an introduction to and a tutorial on the properties of the recently discovered ideal circuit element, a memristor. By definition, a memristor M relates the charge "q" and the magnetic flux [phi] in a circuit and complements a resistor R, a capacitor C and an inductor L as an ingredient of ideal electrical circuits. The properties of…

Fluctuation theory for transport properties in multicomponent mixtures: thermodiffusion and heat conductivity

DEFF Research Database (Denmark)

Shapiro, Alexander

2004-01-01

The theory of transport properties in multicomponent gas and liquid mixtures, which was previously developed for diffusion coefficients, is extended onto thermodiffusion coefficients and heat conductivities. The derivation of the expressions for transport properties is based on the general statis...... of the heat conductivity coefficient for ideal gas. (C) 2003 Elsevier B.V. All rights reserved.......The theory of transport properties in multicomponent gas and liquid mixtures, which was previously developed for diffusion coefficients, is extended onto thermodiffusion coefficients and heat conductivities. The derivation of the expressions for transport properties is based on the general...

The challenges of achieving good electrical and mechanical properties when making structural supercapacitors

Science.gov (United States)

Ciocanel, C.; Browder, C.; Simpson, C.; Colburn, R.

2013-04-01

The paper presents results associated with the electro-mechanical characterization of a composite material with power storage capability, identified throughout the paper as a structural supercapacitor. The structural supercapacitor uses electrodes made of carbon fiber weave, a separator made of Celgard 3501, and a solid PEG-based polymer blend electrolyte. To be a viable structural supercapacitor, the material has to have good mechanical and power storage/electrical properties. The literature in this area is inconsistent on which electrical properties are evaluated, and how those properties are assessed. In general, measurements of capacitance or specific capacitance (i.e. capacitance per unit area or per unit volume) are made, without considering other properties such as leakage resistance and equivalent series resistance of the supercapacitor. This paper highlights the significance of these additional electrical properties, discusses the fluctuation of capacitance over time, and proposes methods to improve the stability of the material's electric properties over time.

The electrical and thermal transport properties of hybrid zigzag graphene-BN nanoribbons

Science.gov (United States)

Gao, Song; Lu, Wei; Zheng, Guo-Hui; Jia, Yalei; Ke, San-Huang

2017-06-01

The electron and phonon transport in hybrid graphene-BN zigzag nanoribbons are investigated by the nonequilibrium Green’s function method combined with density functional theory calculations. A 100% spin-polarized electron transport in a large energy window around the Fermi level is found and this behavior is independent of the ribbon width as long as there contain 3 zigzag carbon chains. The phonon transport calculations show that the ratio of C-chain number to BN-chain number will modify the thermal conductance of the hybrid nanoribbon in a complicated manner.

The electrical and thermal transport properties of hybrid zigzag graphene-BN nanoribbons

International Nuclear Information System (INIS)

Gao, Song; Lu, Wei; Zheng, Guo-Hui; Jia, Yalei; Ke, San-Huang

2017-01-01

The electron and phonon transport in hybrid graphene-BN zigzag nanoribbons are investigated by the nonequilibrium Green’s function method combined with density functional theory calculations. A 100% spin-polarized electron transport in a large energy window around the Fermi level is found and this behavior is independent of the ribbon width as long as there contain 3 zigzag carbon chains. The phonon transport calculations show that the ratio of C-chain number to BN-chain number will modify the thermal conductance of the hybrid nanoribbon in a complicated manner. (paper)

Modelling the electrical properties of concrete for shielding effectiveness prediction

International Nuclear Information System (INIS)

Sandrolini, L; Reggiani, U; Ogunsola, A

2007-01-01

Concrete is a porous, heterogeneous material whose abundant use in numerous applications demands a detailed understanding of its electrical properties. Besides experimental measurements, material theoretical models can be useful to investigate its behaviour with respect to frequency, moisture content or other factors. These models can be used in electromagnetic compatibility (EMC) to predict the shielding effectiveness of a concrete structure against external electromagnetic waves. This paper presents the development of a dispersive material model for concrete out of experimental measurement data to take account of the frequency dependence of concrete's electrical properties. The model is implemented into a numerical simulator and compared with the classical transmission-line approach in shielding effectiveness calculations of simple concrete walls of different moisture content. The comparative results show good agreement in all cases; a possible relation between shielding effectiveness and the electrical properties of concrete and the limits of the proposed model are discussed

Development of Nanoscale Graphitic Devices and The Transport Characterization

International Nuclear Information System (INIS)

Gunasekaran, Venugopal

2011-02-01

This dissertation describes the development of graphitic based nanoscale devices with its fabrication and transport characterization results. It covers graphite nano-scale stacked-junctions fabricated using focused ion beam (FIB) 3-D etching technique, a single layer graphite layer (graphene) preparation and its electrical transport characterization results and the synthesis and investigation of electrical transport behavior of graphene oxide based thin film devices. The first chapter describes the basic information about the carbon family in detail in which the electronic properties and structure of graphite, graphene and graphene oxide are discussed. In addition, the necessity of developing nanoscale graphitic devices is given. The second chapter explains the experimental techniques used in this research for fabricating nanoscale devices which includes focused ion beam 3-D fabrication procedures, mechanical exfoliation technique and photolithographic methods. In third chapter, we have reported the results on temperature dependence of graphite planar-type structures fabricated along ab-plane. In the fourth and fifth chapters, the fabrication and electrical transport characteristics of large in-plane area graphite planar-type structures (fabricated along ab-plane and c-axis) were discussed and their transport anisotropy properties were investigated briefly. In the sixth chapter, we focused the fabrication of the submicron sized graphite stacked junctions and their electrical transport characterization studies. In which, FIB was used to fabricated the submicron junctions with various in-plane area (with same stack height) are and their transport characteristics were compared. The seventh chapter reports investigation of electrical transport results of nanoscale graphite stacked-junctions in which the temperature dependent transport (R-T) studies, current-voltage measurements for the various in-plane areas and for various stack height samples were analyzed. The

Structural, magnetic and electrical properties of Zr-substitued NiZnCo ferrite nanopowders

Energy Technology Data Exchange (ETDEWEB)

Li, Le-Zhong, E-mail: lezhongli@cuit.edu.cn; Zhong, Xiao-Xi; Wang, Rui; Tu, Xiao-Qiang

2017-08-01

Highlights: • The static magnetic properties of NiZnCoZr ferrite nanopowders have been investigated. • The dielectric constant increases with the increase of Zr substitution. • The relaxation peak of tan δ ∼ T curves is observed for x ≥ 0.10. • Electrical transport behavior is found to follow the impurity semiconductor. • The dc resistivity increases at transition temperature with Zr substitution. - Abstract: Zr-substituted NiZnCo ferrite nanopowders, Ni{sub 0.4−x}Zn{sub 0.5}Zr{sub x}Co{sub 0.1}Fe{sub 2.0}O{sub 4} (0 ≤ x ≤ 0.20), were synthesized by the sol-gel auto-combustion method. The effects of Zr substitution on the structural, magnetic and electrical properties have been investigated. The DTA and TG results indicate that there are three steps of combustion process. The X-ray diffraction patterns show that the lattice parameter and the average crystallite size increase with the increase of Zr substitution. The saturation magnetization increases with the increase of Zr substitution when x ≤ 0.05, and then decreases when x > 0.05. Meanwhile, the coercivity initially decreases with the increase of Zr substitution when x ≤ 0.05, and then increases when x > 0.05. The polarization behavior for all the samples in the test frequency range from100 Hz to10 MHz obeys the charge polarization mechanism, which happens since the frequency of the hopping of electron exchange between Fe{sup 2+} and Fe{sup 3+} ions are far from the frequency of alternating-current field. And the dielectric constant increases with the increase of Zr substitution. The relaxation peak of the frequency dependence of dielectric loss is observed for x ≥ 0.10, which is due to the frequency of charge hopping between the Fe{sup 2+} and Fe{sup 3+} exactly matches with the frequency of the external applied field. Electrical transport behavior of the ferrite nanopowders is found to follow the impurity semiconductor, and the effect of Zr substitution on the temperature dependence

Local transport properties, morphology and microstructure of ZnO decorated SiO{sub 2} nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Van Nostrand, Joseph E [Air Force Research Laboratory, Information Directorate, Rome, NY (United States); Cortez, Rebecca [Union College, Schenectady, NY (United States); Rice, Zachary P; Cady, Nathaniel C; Bergkvist, Magnus, E-mail: Joseph.VanNostrand@rl.af.mil [Albany College of Nanoscale Science and Engineering, Albany, NY (United States)

2010-10-15

We report on a novel, surfactant free method for achieving nanocrystalline ZnO decoration of an SiO{sub 2} nanoparticle at ambient temperature. The size distributions of the naked and decorated SiO{sub 2} nanoparticles are measured by means of dynamic light scattering, and a monodisperse distribution is observed for each. The morphology and microstructure of the nanoparticles are explored using atomic force microscopy and high resolution transmission electron microscopy. Investigation of the optical properties of the ZnO decorated SiO{sub 2} nanoparticles shows absorption at 350 nm. This blue shift in absorption as compared to bulk ZnO is shown to be consistent with quantum confinement effects due to the small size of the ZnO nanocrystals. Finally, the local electronic transport properties of the nanoparticles are explored by scanning conductance atomic force microscopy. A memristive hysteresis in the transport properties of the individual ZnO decorated SiO{sub 2} nanoparticles is observed. Optical absorption measurements suggest the presence of oxygen vacancies, whose migration and annihilation appear to contribute to the dynamic conduction properties of the ZnO decorated nanoparticles. We believe this to be the first demonstration of a ZnO decorated SiO{sub 2} nanoparticle, and this represents a simple yet powerful way of achieving the optical and electrical properties of ZnO in combination with the simplicity of SiO{sub 2} synthesis.

Electron transport determines the electrochemical properties of tetrahedral amorphous carbon (ta-C) thin films

International Nuclear Information System (INIS)

Palomäki, Tommi; Wester, Niklas; Caro, Miguel A.; Sainio, Sami; Protopopova, Vera; Koskinen, Jari; Laurila, Tomi

2017-01-01

Amorphous carbon based electrodes are very promising for electrochemical sensing applications. In order to better understand their structure-function relationship, the effect of film thickness on the electrochemical properties of tetrahedral amorphous carbon (ta-C) electrodes was investigated. ta-C thin films of 7, 15, 30, 50 and 100 nm were characterized in detail with Raman spectroscopy, transmission electron microscopy (TEM), conductive atomic force microscopy (c-AFM), scanning tunneling spectroscopy (STS) and X-ray absorption spectroscopy (XAS) to assess (i) the surface properties of the films, (ii) the effect of film thickness on their structure and electrical properties and (iii) the subsequent correlation with their electrochemistry. The electrochemical properties were investigated by cyclic voltammetry (CV) using two different outer-sphere redox probes, Ru(NH 3 ) 6 3+/2+ and FcMeOH, and by electrochemical impedance spectroscopy (EIS). Computational simulations using density functional theory (DFT) were carried out to rationalize the experimental findings. The characterization results showed that the sp 2 /sp 3 ratio increased with decreasing ta-C film thickness. This correlated with a decrease in mobility gap value and an increase in the average current through the films, which was also consistent with the computational results. XAS indicated that the surface of the ta-C films was always identical and composed of a sp 2 -rich layer. The CV measurements indicated reversible reaction kinetics for both outer-sphere redox probes at 7 and 15 nm ta-C films with a change to quasi-reversible behavior at a thickness of around 30 nm. The charge transfer resistance, obtained from EIS measurements, decreased with decreasing film thickness in accordance with the CV results. Based on the characterization and electrochemical results, we conclude that the reaction kinetics in the case of outer-sphere redox systems is determined mainly by the electron transport through the

Temperature dependence of electrical properties of mixture of exogenous neurotransmitters dopamine and epinephrine

Science.gov (United States)

Patki, Mugdha; Patil, Vidya

2016-05-01

Neurotransmitters are chemical messengers that support the communication between the neurons. In vitro study of exogenous neurotransmitters Dopamine and Epinephrine and their mixture, carried out to learn about their electrical properties being dielectric constant and conductivity amongst others. Dielectric constant and conductivity of the selected neurotransmitters are found to increase with temperature. As a result, the time constant of the system increases with temperature. This change leads to increase in the time taken by the synapse to transport the action potential. The correlation between physical properties of exogenous neurotransmitters and psychological and physiological behaviour of human being may be understood with the help of current study. The response time of Epinephrine is in microseconds whereas response time of Dopamine is in milliseconds. The response time for both the neurotransmitters and their mixture is found to be increasing with temperature indicating the symptoms such as depression, apathy, chronic fatigue and low physical energy with no desire to exercise the body, which are observed during the fever.

Core radial electric field and transport in Wendelstein 7-X plasmas

Science.gov (United States)

Pablant, N. A.; Langenberg, A.; Alonso, A.; Beidler, C. D.; Bitter, M.; Bozhenkov, S.; Burhenn, R.; Beurskens, M.; Delgado-Aparicio, L.; Dinklage, A.; Fuchert, G.; Gates, D.; Geiger, J.; Hill, K. W.; Höfel, U.; Hirsch, M.; Knauer, J.; Krämer-Flecken, A.; Landreman, M.; Lazerson, S.; Maaßberg, H.; Marchuk, O.; Massidda, S.; Neilson, G. H.; Pasch, E.; Satake, S.; Svennson, J.; Traverso, P.; Turkin, Y.; Valson, P.; Velasco, J. L.; Weir, G.; Windisch, T.; Wolf, R. C.; Yokoyama, M.; Zhang, D.; W7-X Team

2018-02-01

The results from the investigation of neoclassical core transport and the role of the radial electric field profile (Er) in the first operational phase of the Wendelstein 7-X (W7-X) stellarator are presented. In stellarator plasmas, the details of the Er profile are expected to have a strong effect on both the particle and heat fluxes. Investigation of the radial electric field is important in understanding neoclassical transport and in validation of neoclassical calculations. The radial electric field is closely related to the perpendicular plasma flow (u⊥) through the force balance equation. This allows the radial electric field to be inferred from measurements of the perpendicular flow velocity, which can be measured using the x-ray imaging crystal spectrometer and correlation reflectometry diagnostics. Large changes in the perpendicular rotation, on the order of Δu⊥˜ 5 km/s (ΔEr ˜ 12 kV/m), have been observed within a set of experiments where the heating power was stepped down from 2 MW to 0.6 MW. These experiments are examined in detail to explore the relationship between heating power temperature, and density profiles and the radial electric field. Finally, the inferred Er profiles are compared to initial neoclassical calculations based on measured plasma profiles. The results from several neoclassical codes, sfincs, fortec-3d, and dkes, are compared both with each other and the measurements. These comparisons show good agreement, giving confidence in the applicability of the neoclassical calculations to the W7-X configuration.

Field distribution and DNA transport in solid tumors during electric field-mediated gene delivery.

Science.gov (United States)

Henshaw, Joshua W; Yuan, Fan

2008-02-01

Gene therapy has a great potential in cancer treatment. However, the efficacy of cancer gene therapy is currently limited by the lack of a safe and efficient means to deliver therapeutic genes into the nucleus of tumor cells. One method under investigation for improving local gene delivery is based on the use of pulsed electric field. Despite repeated demonstration of its effectiveness in vivo, the underlying mechanisms behind electric field-mediated gene delivery remain largely unknown. Without a thorough understanding of these mechanisms, it will be difficult to further advance the gene delivery. In this review, the electric field-mediated gene delivery in solid tumors will be examined by following individual transport processes that must occur in vivo for a successful gene transfer. The topics of examination include: (i) major barriers for gene delivery in the body, (ii) distribution of electric fields at both cell and tissue levels during the application of external fields, and (iii) electric field-induced transport of genes across each of the barriers. Through this approach, the review summarizes what is known about the mechanisms behind electric field-mediated gene delivery and what require further investigations in future studies.

Electrical Properties of Zinc-Kaolin Composites below its Percolation ...

African Journals Online (AJOL)

Bheema

In this paper, we present some electrical properties of the zinc-kaolin cermet resistors ..... The temperature coefficient of resistance of a material is generally defined as .... Characterisation and morphological Studies of palladium modified carbon ... conduction and microstructural properties of semiconducting Co-doped TiO2.

Electrical transport in strained silicon quantum wells on vicinal substrates

International Nuclear Information System (INIS)

Kaya, S.

1999-01-01

This thesis deals with the electrical transport studies of strained Si quantum wells grown on tilted Si substrates. Magnetotransport measurements at very low temperatures are used to investigate the high electron mobility, scattering processes and modified band structure for four different substrate orientations (2, 4, 6 and 10 deg.) and in two different directions of transport. We first discuss the morphology of the tilted system with the aid of, atomic force and optical microscopy. A clear change of surface morphology of tilted layers in comparison with the (001) type surfaces is explained by the degree of tilt in the system. The electron mobility and in-plane effective mass becomes anisotropic, which scale roughly with the tilt angle. The mobility anisotropy is shown to be the result of extra scattering when electrons travel across the steps common to vicinal surfaces. The extra scattering has characteristics similar to interface roughness scattering, as inferred from the trend that the transport (τ t ) and quantum scattering (τ q ) times follow. As the tilt angle grows, it is found that τ t /τ q →1 in the direction perpendicular to the steps. Electrons in tilted channels of multivalley semiconductors can involve a new interband scattering mechanism due to a one dimensional minigap opening in the conduction band. This effect, known from bulk Si MOSFETs, is investigated in strained Si for the first time in this thesis. First, the effect of applied electric fields on electron conduction is considered. Shubnikov-de Haas oscillations in the magnetoresistance data indicate a remarkably different electron scattering behaviour in tilted samples with increasing fields in directions parallel and perpendicular to the tilt direction. An FFT analysis of the data produces extra peaks in the electron density spectra. By clear contrast, flat samples grown under similar conditions do not show any unusual features. The difference is attributed to the existence of a minigap

Hybrid-Electric and Distributed Propulsion Technologies for Large Commercial Transports: A NASA Perspective

Science.gov (United States)

Madavan, Nateri K.; Del Rosario, Ruben; Jankovsky, Amy L.

2015-01-01

Develop and demonstrate technologies that will revolutionize commercial transport aircraft propulsion and accelerate development of all-electric aircraft architectures. Enable radically different propulsion systems that can meet national environmental and fuel burn reduction goals for subsonic commercial aircraft. Focus on future large regional jets and single-aisle twin (Boeing 737- class) aircraft for greatest impact on fuel burn, noise and emissions. Research horizon is long-term but with periodic spinoff of technologies for introduction in aircraft with more- and all-electric architectures. Research aligned with new NASA Aeronautics strategic R&T thrusts in areas of transition to low-carbon propulsion and ultra-efficient commercial transports.

Possibility of internal transport barrier formation and electric field bifurcation in LHD plasma

International Nuclear Information System (INIS)

Sanuki, H.; Itoh, K.; Yokoyama, M.; Fujisawa, A.; Ida, K.; Toda, S.; Itoh, S.-I.; Yagi, M.; Fukuyama, A.

1999-05-01

Theoretical analysis of the electric field bifurcation is made for the LHD plasma. For given shapes of plasma profiles, a region of bifurcation is obtained in a space of the plasma parameters. In this region of plasma parameters, the electric field domain interface is predicted to appear in the plasma column. The reduction of turbulent transport is expected to occur in the vicinity of the interface, inducing a internal transport barrier. Within this simple model, the plasma with internal barriers is predicted to be realized for the parameters of T e (0) ∼ 2 keV and n(0) ≅ 10 18 m -3 . (author)

Magnetic and transport properties of the 1201-phase Tl0.94Sr2Cu0.4Co0.6O5-δ

International Nuclear Information System (INIS)

Seshadri, R.; Maignan, A.; Martin, C.; Letouze, F.; Raveau, B.

1997-01-01

We present the magnetic and transport properties of a mixed oxide of Cu and Co with the prototypic structure of the Tl containing copper oxide superconductors. This insulating phase shows a transition to a spin-glass state with an equilibrium transition temperature T c =30.9(1) K. Interestingly, the electrical transport, which seems to be dominated by disorder effects, demonstrates giant negative magnetoresistance (GMR) at low temperatures, with the magnitude of the GMR increasing as the temperature is decreased. The possible cause for the spin-glass behavior as well as the GMR seems to be site disorder of Cu/Co and the simultaneous presence of ferro- and antiferromagnetic interactions. The GMR seems to be different from what is observed in the ferromagnetic manganites in that the transport properties do not closely trace the magnetic behavior. copyright 1997 The American Physical Society

Electrical properties of fast ion conducting silver based borate glasses: Application in solid battery

International Nuclear Information System (INIS)

Masoud, Emad M.; Khairy, M.; Mousa, M.A.

2013-01-01

Graphical abstract: -- Highlights: •AgI dopant created more opened borate network structure. •Dielectric constant and loss values increased with AgI concentration. •AgI dopant enhanced both ion migration and orientation. •0.6 AgI–0.27 Ag 2 O–0.13 B 2 O 3 showed the highest DC-conductivity at room temperature. •It showed also good life time as a solid electrolyte in solid battery at room temperature. -- Abstract: The electrical properties of the ternary ionic conducting glass system xAgI–(1 – x)[0.67Ag 2 O–0.33B 2 O 3 ], where x = 0.4 , 0.5, 0.6, 0.7 and 0.8, were studied for emphasizing the influence of silver iodide concentration on the transport properties in the based borate glasses. The glasses were prepared by melt quenching technique and characterized using X-ray diffraction (XRD), FT-IR spectra and differential thermal analysis (DTA). XRD confirmed a glassy nature for all investigated compositions. Electrical conductivity (σ), dielectric constant (ε′), dielectric loss (ε ″ ) and impedance spectra (Z′–Z′′) were studied for all samples at a frequency range of 0–10 6 Hz and over a temperature range of 303–413 K. Changes of conductivity and dielectric properties with composition, temperature and frequency were analyzed and discussed. A silver iodine battery using glassy electrolyte sample with the highest ionic conductivity (x = 0.6) was studied

A Comparative Assessment of Life-Cycle Greenhouse Gas Emissions from Hypothetical Electric Airport Transportation Services in Thailand

Science.gov (United States)

Koiwanit, J.

2018-05-01

Global warming is an increase of average temperature in the atmosphere, which causes adverse effects on the environment. Carbon dioxide (CO2) from transportation sector is one of the main contributors of the overall greenhouse gases (GHG). To cope with this issue, electric car services are increasingly seen as popular alternative modes of green transportation especially for urban cities as it is more flexible, more environmentally-friendly, and less expensive than the use of conventional vehicles. The study analyses and compare the hypothetical electric car systems from airport transportation services. Center of Environmental Science of Leiden University (CML) 2001, the Life Cycle Impact Assessment (LCIA) method, is applied to convert life cycle inventory data into environmental impacts. The observed results showed that the electric shuttle bus had the highest impact in global warming potential (GWP) compared to other transportation types. Alternatively, this Life Cycle Assessment (LCA) study that evaluated different transportations provided important information for decision makers on quantifying the differences between each scenario.

Thermodynamic properties and transport coefficients of a two-temperature polytetrafluoroethylene vapor plasma for ablation-controlled discharge applications

International Nuclear Information System (INIS)

Wang, Haiyan; Qi, Haiyang; Wang, Weizong; Yan, Joseph D; Geng, Jinyue; Wu, Yaowu

2017-01-01

Ablation-controlled plasmas have been used in a range of technical applications where local thermodynamic equilibrium (LTE) is often violated near the wall due to the strong cooling effect caused by the ablation of wall materials. The thermodynamic and transport properties of ablated polytetrafluoroethylene (PTFE) vapor, which determine the flowing plasma behavior in such applications, are calculated based on a two-temperature model at atmospheric pressure. To our knowledge, no data for PTFE have been reported in the literature. The species composition and thermodynamic properties are numerically determined using the two-temperature Saha equation and the Guldberg–Waage equation according to van de Sanden et al ’s derivation. The transport coefficients, including viscosity, thermal conductivity and electrical conductivity, are calculated with the most recent collision interaction potentials using Devoto’s electron and heavy-particle decoupling approach but expanded to the third-order approximation (second-order for viscosity) in the frame of the Chapman–Enskog method. Results are computed for different degrees of thermal non-equilibrium, i.e. the ratio of electron to heavy-particle temperatures, from 1 to 10, with electron temperature ranging from 300 to 40 000 K. Plasma transport properties in the LTE state obtained from the present work are compared with existing published results and the causes for the discrepancy analyzed. The two-temperature plasma properties calculated in the present work enable the modeling of wall ablation-controlled plasma processes. (paper)

Thermodynamic properties and transport coefficients of a two-temperature polytetrafluoroethylene vapor plasma for ablation-controlled discharge applications

Science.gov (United States)

Wang, Haiyan; Wang, Weizong; Yan, Joseph D.; Qi, Haiyang; Geng, Jinyue; Wu, Yaowu

2017-10-01

Ablation-controlled plasmas have been used in a range of technical applications where local thermodynamic equilibrium (LTE) is often violated near the wall due to the strong cooling effect caused by the ablation of wall materials. The thermodynamic and transport properties of ablated polytetrafluoroethylene (PTFE) vapor, which determine the flowing plasma behavior in such applications, are calculated based on a two-temperature model at atmospheric pressure. To our knowledge, no data for PTFE have been reported in the literature. The species composition and thermodynamic properties are numerically determined using the two-temperature Saha equation and the Guldberg-Waage equation according to van de Sanden et al’s derivation. The transport coefficients, including viscosity, thermal conductivity and electrical conductivity, are calculated with the most recent collision interaction potentials using Devoto’s electron and heavy-particle decoupling approach but expanded to the third-order approximation (second-order for viscosity) in the frame of the Chapman-Enskog method. Results are computed for different degrees of thermal non-equilibrium, i.e. the ratio of electron to heavy-particle temperatures, from 1 to 10, with electron temperature ranging from 300 to 40 000 K. Plasma transport properties in the LTE state obtained from the present work are compared with existing published results and the causes for the discrepancy analyzed. The two-temperature plasma properties calculated in the present work enable the modeling of wall ablation-controlled plasma processes.

Study on the electrical transport properties of La{sub 2/3}Ba{sub 1/3}MnO{sub 3}:Ag{sub 0.04}/LaAlO{sub 3} (001) films

Energy Technology Data Exchange (ETDEWEB)

Liu, Xiang, E-mail: lxjim@126.com; Zhao, Shuang; Zhang, Shao-Chun

2017-01-01

La{sub 2/3}Ba{sub 1/3}MnO{sub 3}: wt%Ag{sub x} (LBMO:Ag{sub x}, x=0.04) films were prepared on single crystalline (001)-orientated LaAlO{sub 3} substrates by pulsed laser deposition technique. All the samples show along the (00l) orientation in rhombohedral structure with R3c space group. The surface roughness (Ra), insulator-metal transition temperature (Tp) and resistivity at Tp (ρ{sub Tp}) of the LBMO:Ag{sub 0.04} films reached optimal values of 3.29 nm, 288 K and 0.033 Ω cm at 740 °C, respectively. The improvement of electrical transport properties in the films are attributed to the optimal growth temperature and Ag-doping improve the microstructure of the surfaces, grain boundaries (GBs) in connectivity and better crystallization. In addition, the electrical conduction behaviors can be well fitted with the grain/domain boundary, electron–electron and magnon scattering mechanisms in the ferromagnetic metallic region (TTp).

Polycrystalline Mg2Si thin films: A theoretical investigation of their electronic transport properties

International Nuclear Information System (INIS)

Balout, H.; Boulet, P.; Record, M.-C.

2015-01-01

The electronic structures and thermoelectric properties of a polycrystalline Mg 2 Si thin film have been investigated by first-principle density-functional theory (DFT) and Boltzmann transport theory calculations within the constant-relaxation time approximation. The polycrystalline thin film has been simulated by assembling three types of slabs each having the orientation (001), (110) or (111) with a thickness of about 18 Å. The effect of applying the relaxation procedure to the thin film induces disorder in the structure that has been ascertained by calculating radial distribution functions. For the calculations of the thermoelectric properties, the energy gap has been fixed at the experimental value of 0.74 eV. The thermoelectric properties, namely the Seebeck coefficient, the electrical conductivity and the power factor, have been determined at three temperatures of 350 K, 600 K and 900 K with respect to both the energy levels and the p-type and n-type doping levels. The best Seebeck coefficient is obtained at 350 K: the S yy component of the tensor amounts to about ±1000 μV K −1 , depending on the type of charge carriers. However, the electrical conductivity is much too small which results in low values of the figure of merit ZT. Structure–property relationship correlations based on directional radial distribution functions allow us to tentatively draw some explanations regarding the anisotropy of the electrical conductivity. Finally, the low ZT values obtained for the polycrystalline Mg 2 Si thin film are paralleled with those recently reported in the literature for bulk chalcogenide glasses. - Graphical abstract: Structure of the polycrystalline thin film of Mg 2 Si. - Author-Highlights: • Polycrystalline Mg 2 Si film has been modelled by DFT approach. • Thermoelectric properties have been evaluated by semi-classical Boltzmann theory. • The structure was found to be slightly disordered after relaxation. • The highest value of Seebeck

Effects of transportation during the hot season, breed and electrical stimulation on histochemical and meat quality characteristics of goat longissimus muscle.

Science.gov (United States)

Kadim, Isam T; Mahgoub, Osman; Al-Marzooqi, Waleed; Khalaf, Samera; Al-Sinawi, Shadia S H; Al-Amri, Issa

2010-06-01

The effects of transportation and electrical stimulation (90 V) on physiological, histochemical and meat quality characteristics of two breeds of Omani goats were assessed. Twenty 1-year-old male goats from each breed (Batina and Dhofari) were divided into two groups: 3 h transported during the hot season (42 degrees C day time temperature) and non-transported. Animals were blood-sampled before loading and prior to slaughter. Electrical stimulation was applied 20 min postmortem to 50% randomly selected carcasses of both breeds. Temperature and pH decline of the Longissimus was monitored. Ultimate pH, shear force, sarcomere length, myofibrillar fragmentation index, expressed juice, cooking loss and colour were measured from samples of Longissimus dorsi muscles. Electrical stimulation and transportation had a significant effect on most biochemical and meat quality characteristics of Longissimus dorsi. The transported goats had higher plasma cortisol (P goats. Electrical stimulation resulted in a significantly (P Meat from transported goats had significantly higher pH, expressed juice and shear force, but contained significantly lower sarcomere length and L* values than non-transported goats. The proportion of the myosin ATPase staining did not change as a function of stimulation, transportation or breed. These results indicated that subjecting goats to transportation for 3 h under high ambient temperatures can generate major physiological and muscle metabolism responses. Electrical stimulation improved quality characteristics of meat from both groups. This indicates that electrical stimulation may reduce detrimental effects of transportation on meat quality of Omani goats.

The effects of thermal annealing on the structure and the electrical transport properties of ultrathin gadolinia-doped ceria films grown by pulsed laser deposition

Energy Technology Data Exchange (ETDEWEB)

Rodrigo, K.; Pryds, N.; Theil Kuhn, L.; Esposito, V.; Linderoth, S. [Technical University of Denmark, Fuel Cells and Solid State Chemistry Division, Risoe DTU, Roskilde (Denmark); Heiroth, S.; Lippert, T. [Paul Scherrer Institute, General Energy Research Department, Villigen PSI (Switzerland); Schou, J. [Technical University of Denmark, Department of Photonics Engineering, Roskilde (Denmark)

2011-09-15

Ultrathin crystalline films of 10 mol% gadolinia-doped ceria (CGO10) are grown on MgO (100) substrates by pulsed laser deposition at a moderate temperature of 400 C. As-deposited CGO10 layers of approximately 4 nm, 14 nm, and 22 nm thickness consist of fine grains with dimensions {<=}{proportional_to}11 nm. The films show high density within the thickness probed in the X-ray reflectivity experiments. Thermally activated grain growth, density decrease, and film surface roughening, which may result in the formation of incoherent CGO10 islands by dewetting below a critical film thickness, are observed upon heat treatment at 400 C and 800 C. The effect of the grain coarsening on the electrical characteristics of the layers is investigated and discussed in the context of a variation of the number density of grain boundaries. The results are evaluated with regard to the use of ultrathin CGO10 films as seeding templates for the moderate temperature growth of thick solid electrolyte films with improved oxygen transport properties. (orig.)

Charge Injection and Transport in Metal/Polymer Chains/Metal Sandwich Structure

International Nuclear Information System (INIS)

Hai-Hong, Li; Dong-Mei, Li; Yuan, Li; Kun, Gao; De-Sheng, Liu; Shi-Jie, Xie

2008-01-01

Using the tight-binding Su–Schrieffer–Heeger model and a nonadiabatic dynamic evolution method, we study the dynamic processes of the charge injection and transport in a metal/two coupled conjugated polymer chains/metal structure. It is found that the charge interchain transport is determined by the strength of the electric field and the magnitude of the voltage bias applied on the metal electrode. The stronger electric field and the larger voltage bias are both in favour of the charge interchain transport. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

The electric and thermoelectric properties of Cu(II)-Schiff base nano-complexes

Science.gov (United States)

Ibrahim, E. M. M.; Abdel-Rahman, Laila H.; Abu-Dief, Ahmed M.; Elshafaie, A.; Hamdan, Samar Kamel; Ahmed, A. M.

2018-05-01

The physical properties, such as electric and optical properties, of metal-Schiff base complexes have been widely investigated. However, their thermoelectric (TE) properties remain unreported. This work presents Cu(II)-Schiff base complexes as promising materials for TE power generation. Therefore, three Cu(II)-Schiff base complexes (namely, [Cu(C32H22N4O2)].3/2H2O, [Cu(C23H17N4O7Br)], and [Cu(C27H22N4O8)].H2O) have been synthesized in nanosized scale. The electric and TE properties have been studied and comprehensive discussions have been presented to promote the nano-complexes (NCs) practical applications in the field of TE power generation. The electrical measurements confirm that the NCs are semiconductors and the electrical conduction process is governed by intermolecular and intramolecular transfer of the charge carriers. The TE measurements reveal that the Cu(II)-Schiff base NCs are nondegenerate P-type semiconductors. The measured Seebeck coefficient values were higher compared to the values reported in previous works for other organic materials indicating that the complexes under study are promising candidates for theremoelectric applications if the electrical conductivity could be enhanced.

Intense heavy-ion beam transport with electric and magnetic quadrupoles

International Nuclear Information System (INIS)

Fessenden, T.J.; Hopkins, H.S.

1995-08-01

As part of the small induction recirculator development at LLNL, the authors are testing an injector and transport line that delivers 4 micros beams of potassium with repetition rates up to 10 Hz at a nominal current of 2 mA. The normalized K-V equivalent emittance of the beams is near 0.02 π mm-mrad and is mostly determined by the temperature of the source (0.1 eV). K + ions generated at 80 keV in a Pierce diode are matched to an alternating gradient transport line by seven electric quadrupoles. Two additional quads have been modified to serve as two-axis steerers. The matching section is followed by a transport section comprised of seven permanent magnet quadrupoles. Matching to this section is achieved by adjusting the voltages on the electric quadrupoles to voltages calculated by an envelope matching code. Measurements of beam envelope parameters are made at the matching section entrance and exit as well as at the end of the permanent magnet transport section. Beam current waveforms along the experiment are compared with results from a one-dimension longitudinal dynamics code. Initial experiments show particle loss occurring at the beam head as a result of overtaking. The apparatus is also being used for the development of non or minimally intercepting diagnostics for future recirculator experiments. These include capacitive monitors for determining beam line-charge density and position in the recirculator; flying wire scanners for beam position; and gated TV scanners for measuring beam profiles and emittance

Proceedings of the Prop'Elec 2000 colloquium. Advances of electric drive in urban transportation systems; Actes du colloque Prop'Elec 2000. Progres de la traction electrique dans les transports urbains

Energy Technology Data Exchange (ETDEWEB)

NONE

2000-07-01

This document is the proceedings of Prop'Elec 2000 colloquium on the advances in electric power drive in urban transportation systems. The colloquium comprises 5 sessions dealing with: 1 - public collective electric-powered transportation system: synthesis of urban guided systems (C. Soulas, INRETS), the fast travelator (A. Cote, RATP), the power supply system of METEOR automatic underground railway (P. Lagrange, W. Seiler, RATP); 2 - electrical drive in urban transportation systems: start-up of a thermal engine with super-capacitors (D. Bouquain (CREEBEL), H. Gualous, A. Djerdir, A. Berthon, J.M. Kauffmann (L2ES, IGE)), The LEV (light weight electric vehicle) project in Mendrisio (U. Schwegler, LEV/Suisse), prototype of electrical bike that use a wheel-engine (C. Espanet, F. Gustin, J.M. Kauffmann (IGE), S. Robert, M. Karmous (EICN)), TWIL: a new generation of small electrical bikes (E. Escallot, T. Bontems (EPMI)), thermal and magnetic analysis of a rectilinear movement actuator (J.C. Vannier, M. Kadiri (SUPELEC)), torque undulation and vibrations in automobile electrical drives (A.L. Bui-Van (Renault), A. Fonseca (LEG)); 3 - collective electric-powered transportation systems: STARS: autonomous transportation system with flywheel charging at the station (P. Gibard (Alstom Transport), K. Abuda, J.M. Vinassa (IXL Bordeaux)), Translhor tramway: presentation of the drive system (L. Verdier, LHOR); 4 - electric-powered and hybrid vehicles: batteries for electric-powered vehicles (J.F. Fauvarque, CNAM), Li-ion batteries and their application in automotive industry (T. Faugeras, SAFT), optimized drive systems for electric-powered vehicles (J. Saint-Michel, Leroy Somer), the Citroen Xsara Dynactive (S. Derou, PSA), 5 - electric-powered and hybrid vehicles: the electrical car in tomorrows' city (M. Parent, INRIA), the market of electric-powered vehicles in France and Europe (M. Valet, PSA). (J.S.)

Monitoring snowmelt and solute transport at Oslo airport by combining time-lapse electrical resistivity, soil water sampling and tensiometer measurements

Science.gov (United States)

Bloem, E.; French, H. K.

2013-12-01

Monitoring contaminant transport at contaminated sites requires optimization of the configuration of a limited number of samplings points combined with heterogeneous flow and preferential flowpaths. Especially monitoring processes in the unsaturated zone is a major challenge due to the limited volume monitored by for example suction cups and their risk to clog in a highly active degradation zone. To make progress on soil contamination assessment and site characterization there is a strong need to integrate field-sale extensively instrumented tools, with non-invasive (geophysical) methods which provide spatially integrated measurements also in the unsaturated zone. Examples of sites that might require monitoring activities in the unsaturated zone are airports with winter frost where large quantities of de-icing chemicals are used each winter; salt and contaminant infiltration along roads; constructed infiltration systems for treatment of sewerage or landfill seepage. Electrical resistivity methods have proved to be useful as an indirect measurement of subsurface properties and processes at the field-scale. The non-uniqueness of the interpretation techniques can be reduced by constraining the inversion through the addition of independent geophysical measurements along the same profile. Or interpretation and understanding of geophysical images can be improved by the combination with classical measurements of soil physical properties, soil suction, contaminant concentration and temperatures. In our experiment, at the research field station at Gardermoen, Oslo airport, we applied a degradable de-icing chemical and an inactive tracer to the snow cover prior to snowmelt. To study the solute transport processes in the unsaturated zone time-lapse cross borehole electrical resistivity tomography (ERT) measurements were conducted at the same time as soil water samples were extracted at multiple depths with suction cups. Measurements of soil temperature, and soil tension were

Kinetic parameters, collision rates, energy exchanges and transport coefficients of non-thermal electrons in premixed flames at sub-breakdown electric field strengths

KAUST Repository

Bisetti, Fabrizio

2014-01-02

The effects of an electric field on the collision rates, energy exchanges and transport properties of electrons in premixed flames are investigated via solutions to the Boltzmann kinetic equation. The case of high electric field strength, which results in high-energy, non-thermal electrons, is analysed in detail at sub-breakdown conditions. The rates of inelastic collisions and the energy exchange between electrons and neutrals in the reaction zone of the flame are characterised quantitatively. The analysis includes attachment, ionisation, impact dissociation, and vibrational and electronic excitation processes. Our results suggest that Townsend breakdown occurs for E/N = 140 Td. Vibrational excitation is the dominant process up to breakdown, despite important rates of electronic excitation of CO, CO2 and N2 as well as impact dissociation of O2 being apparent from 50 Td onwards. Ohmic heating in the reaction zone is found to be negligible (less than 2% of peak heat release rate) up to breakdown field strengths for realistic electron densities equal to 1010 cm-3. The observed trends are largely independent of equivalence ratio. In the non-thermal regime, electron transport coefficients are insensitive to mixture composition and approximately constant across the flame, but are highly dependent on the electric field strength. In the thermal limit, kinetic parameters and transport coefficients vary substantially across the flame due to the spatially inhomogeneous concentration of water vapour. A practical approach for identifying the plasma regime (thermal versus non-thermal) in studies of electric field effects on flames is proposed. © 2014 Taylor & Francis.

Memory and Electrical Properties of (100-Oriented AlN Thin Films Prepared by Radio Frequency Magnetron Sputtering

Directory of Open Access Journals (Sweden)

Maw-Shung Lee

2014-01-01

Full Text Available The (100-oriented aluminum nitride (AlN thin films were well deposited onto p-type Si substrate by radio frequency (RF magnetron sputtering method. The optimal deposition parameters were the RF power of 350 W, chamber pressure of 9 mTorr, and nitrogen concentration of 50%. Regarding the physical properties, the microstructure of as-deposited (002- and (100-oriented AlN thin films were obtained and compared by XRD patterns and TEM images. For electrical properties analysis, we found that the memory windows of (100-oriented AlN thin films are better than those of (002-oriented thin films. Besides, the interface and interaction between the silicon and (100-oriented AlN thin films was serious important problem. Finally, the current transport models of the as-deposited and annealed (100-oriented AlN thin films were also discussed. From the results, we suggested and investigated that large memory window of the annealed (100-oriented AlN thin films was induced by many dipoles and large electric field applied.

Oxygen transport properties estimation by DSMC-CT simulations

Energy Technology Data Exchange (ETDEWEB)

Bruno, Domenico [Istituto di Metodologie Inorganiche e dei Plasmi, Consiglio Nazionale delle Ricerche - Via G. Amendola, 122 - 70125 Bari (Italy); Frezzotti, Aldo; Ghiroldi, Gian Pietro [Dipartimento di Scienze e Tecnologie Aerospaziali, Politecnico di Milano - Via La Masa, 34 - 20156 Milano (Italy)

2014-12-09

Coupling DSMC simulations with classical trajectories calculations is emerging as a powerful tool to improve predictive capabilities of computational rarefied gas dynamics. The considerable increase of computational effort outlined in the early application of the method (Koura,1997) can be compensated by running simulations on massively parallel computers. In particular, GPU acceleration has been found quite effective in reducing computing time (Ferrigni,2012; Norman et al.,2013) of DSMC-CT simulations. The aim of the present work is to study rarefied Oxygen flows by modeling binary collisions through an accurate potential energy surface, obtained by molecular beams scattering (Aquilanti, et al.,1999). The accuracy of the method is assessed by calculating molecular Oxygen shear viscosity and heat conductivity following three different DSMC-CT simulation methods. In the first one, transport properties are obtained from DSMC-CT simulations of spontaneous fluctuation of an equilibrium state (Bruno et al, Phys. Fluids, 23, 093104, 2011). In the second method, the collision trajectory calculation is incorporated in a Monte Carlo integration procedure to evaluate the Taxman’s expressions for the transport properties of polyatomic gases (Taxman,1959). In the third, non-equilibrium zero and one-dimensional rarefied gas dynamic simulations are adopted and the transport properties are computed from the non-equilibrium fluxes of momentum and energy. The three methods provide close values of the transport properties, their estimated statistical error not exceeding 3%. The experimental values are slightly underestimated, the percentage deviation being, again, few percent.

Transport properties of quasi-free Fermions

CERN Document Server

Aschbacher, W; Pautrat, Y; Pillet, C A

2006-01-01

Using the scattering approach to the construction of Non-Equilibrium Steady States proposed by Ruelle we study the transport properties of systems of independent electrons. We show that Landauer-Buttiker and Green-Kubo formulas hold under very general conditions.

Electrical properties of undoped zinc oxide nanostructures at different annealing temperature

Energy Technology Data Exchange (ETDEWEB)

Nasir, M. F., E-mail: babaibaik2002@yahoo.com; Zainol, M. N., E-mail: nizarzainol@yahoo.com; Hannas, M., E-mail: mhannas@gmail.com [NANO-ElecTronic Centre (NET), Faculty of Electrical Engineering, Universiti Teknologi MARA (UiTM), 40450 Shah Alam, Selangor (Malaysia); Mamat, M. H., E-mail: mhmamat@salam.uitm.edu.my; Rusop, Mohamad, E-mail: rusop@salam.uitm.edu.my [NANO-ElecTronic Centre (NET), Faculty of Electrical Engineering, Universiti Teknologi MARA (UiTM), 40450 Shah Alam, Selangor (Malaysia); NANO-SciTech Centre (NST), Institute of Science (IOS), Universiti Teknologi MARA - UiTM, 40450 Shah Alam, Selangor (Malaysia); Rahman, S. A., E-mail: saadah@um.edu.my [NANO-ElecTronic Centre (NET), Faculty of Electrical Engineering, Universiti Teknologi MARA (UiTM), 40450 Shah Alam, Selangor (Malaysia); Low Dimensional Materials Research Centre, Physics Department, Faculty of Science, University of Malaya, 50603 Kuala Lumpur (Malaysia)

2016-07-06

This project has been focused on the electrical and optical properties respectively on the effect of Undoped zinc oxide (ZnO) thin films at different annealing temperature which is varied 400 °C, 450 °C, 500 °C, and 550 °C.Undoped ZnO solutions were deposited onto the glass substrates using sol-gel spin coating method. This project was involved with three phases, which are thin films preparation, deposition and characterization. The thin films were characterized using Current Voltage (I-V) measurement and UV-vis-NIR spectrophotometer for electrical properties and optical properties. The electrical properties show that the resistivity is the lowest at 500 °C which its resistivity is 5.36 × 10{sup 4} Ωcm{sup −1}. The absorption coefficient spectrum obtained from UV-Vis-NIR spectrophotometer measurement shows all films exhibit very low absorption in the visible (400-800 nm) and near infrared (NIR) (>800 nm) range but exhibit high absorption in the UV range.

Structural and electrical properties of amorphous carbon–sulfur ...

Indian Academy of Sciences (India)

Unknown

Amorphous carbon films; pyrolysis; scanning electron microscopy; electrical properties; thermal analysis. 1. Introduction ... phorus compounds may have useful mechanical or elec- .... SEM images of a-C:S samples with different S/P values.

Integration of a Folding Electric two-wheeler vehicle for a future commuting transportation

DEFF Research Database (Denmark)

Gudmundsson, Bjami Freyr; Larsen, Esben

2012-01-01

The paper issues the development, building and testing of a Folding Electric Motorbike, a lightweight, low cost and all-electric two-wheeler vehicle taking full advantage on today's city infrastructure. The technology offers drivers to combine transportation methods, lowering cost, and greenhouse......-electric two-wheeler vehicle taking full advantage on today's city infrastructure is very prospective. The alpha-prototype was successfully constructed and is considered to be ready for further laboratory testing and test driving before continuations on a fully designed beta-prototype....

Electrical transport properties of V2O5 thin films obtained by thermal annealing of layers grown by RF magnetron sputtering at room temperature

International Nuclear Information System (INIS)

Giannetta, H.M.R.; Calaza, C.; Lamas, D.G.; Fonseca, L.; Fraigi, L.

2015-01-01

The present study investigates the main electrical transport mechanism in V 2 O 5 thin films deposited by RF magnetron sputtering on the basis of the Mott's small polaron hopping model. The material under test was obtained at room temperature from a V 2 O 5 target and then oxidized at high temperature under air atmosphere to obtain the desired V 2 O 5 phase. The dependence of the electrical conductivity of the V 2 O 5 thin films with temperature was analyzed using the Mott's small polarons hopping transport model under the Schnakenberg form. Model results suggest a polaron binding energy W H = 0.1682 eV, with a structural disorder energy W D = 0.2241 eV and an optical phonon frequency ν 0 = 0.468 × 10 13 s −1 . These results are in agreement with data reported in literature for single crystal V 2 O 5 . However, the carrier mobility μ = 1.5019 × 10 −5 cm 2 /Vs computed in the non-adiabatic regime is significantly smaller than that of the single crystal, suggesting a strong electron–phonon coupling in the V 2 O 5 thin films obtained with the proposed deposition method. - Highlights: • A two-stage deposition method compatible with lift-off patterning is proposed. • V 2 O 5 films are deposited by RF magnetron sputtering and then annealed in air. • Films are analyzed by SEM and its pure phase nature is confirmed by XRD. • Electrical conductivity was fitted using Mott's model for small polarons. • Fit derived parameters confirm charge transport through small-polarons hopping

Electrical properties of air in the Carlsbad Caverns

International Nuclear Information System (INIS)

Wilkening, M.; Romero, V.

1980-01-01

Radon 222 and its daughter product concentrations in the Carlsbad Caverns are higher than in outdoor air by a factor of several hundred. The effects of the radiation from these substances on the electrical properties of air in the cave have been studied. The rate of ion-pair production, the ion density, and the electrical conductivity are much higher in the Cave than in outdoor air. The mobility of the ions is less than outdoors due to the high humidity and low condensation nuclei concentration. A small net space charge produces a barely detectable electric field of the order of one percent of the earth's fair weather field

Spin transport, magnetoresistance, and electrically detected magnetic resonance in amorphous hydrogenated silicon nitride

Energy Technology Data Exchange (ETDEWEB)

Mutch, Michael J. [Intercollege Program of Materials, Pennsylvania State University, University Park, Pennsylvania 16802 (United States); Lenahan, Patrick M. [Intercollege Program of Materials, Pennsylvania State University, University Park, Pennsylvania 16802 (United States); Department of Engineering Science and Mechanics, Pennsylvania State University, University Park, Pennsylvania 16802 (United States); King, Sean W. [Logic Technology Development, Intel Corporation, Hillsboro, Oregon 97124 (United States)

2016-08-08

We report on a study of spin transport via electrically detected magnetic resonance (EDMR) and near-zero field magnetoresistance (MR) in silicon nitride films. Silicon nitrides have long been important materials in solid state electronics. Although electronic transport in these materials is not well understood, electron paramagnetic resonance studies have identified a single dominating paramagnetic defect and have also provided physical and chemical descriptions of the defects, called K centers. Our EDMR and MR measurements clearly link the near-zero field MR response to the K centers and also indicate that K center energy levels are approximately 3.1 eV above the a-SiN:H valence band edge. In addition, our results suggest an approach for the study of defect mediated spin-transport in inorganic amorphous insulators via variable electric field and variable frequency EDMR and MR which may be widely applicable.

Effect of d-wave pairing symmetry in transport properties of silicene-based superconductor junction

Science.gov (United States)

Vosoughi-nia, S.; Rashedi, G.; hajati, Y.

2018-06-01

We theoretically study the tunneling conductance of a normal/d-wave superconductor silicene junction using Blonder-Tinkham-Klapwijk (BTK) formalism. We discuss how the conductance spectra are affected by changing the chemical potential (μN) in the normal silicene region. It is obtained that the amplitude of the spin/valley-dependent Andreev reflection (AR) and charge conductance (G) of the junction can be strongly modulated by the orientation angle of superconductive gap (β) and perpendicular electric field (Ez). We demonstrate that the charge conductance exhibits an oscillatory behavior as a function of β by a period of π/2. Remarkably, variation of μN strongly modifies the amplitude of the oscillations and periodically there are transport gaps in the G - β oscillations for a range of μN. These findings suggest that one may experimentally tune the transport properties of the junction through changing β, Ez and μN.

Microstructure and electrical properties of bismuth and bismuth oxide deposited by magnetron sputtering UBM

International Nuclear Information System (INIS)

Otalora B, D. M.; Dussan, A.; Olaya F, J. J.

2015-01-01

In this work, bismuth (Bi) and bismuth oxide (Bi 2 O 3 ) thin films were prepared, at room temperature, by Sputtering Unbalanced Magnetron (UBM - Unbalance Magnetron) technique under glass substrates. Microstructural and electrical properties of the samples were studied by X-ray diffraction (XRD) and System for Measuring Physical Properties - PPMS (Physical Property Measurement System). Dark resistivity of the material was measured for a temperature range between 100 and 400 K. From the XRD measurements it was observed a polycrystalline character of the Bi associated to the presence of phases above the main peak, 2θ = 26.42 grades and a growth governed by a rhombohedral structure. Crystal parameters were obtained for both compounds, Bi and Bi 2 O 3 . From the analysis of the spectra of the conductivity as a function of temperature, it was established that the transport mechanism that governs the region of high temperature (T>300 K) is thermally activated carriers. From conductivity measurements the activation energies were obtained of 0.0094 eV and 0.015 eV for Bi 2 O 3 and Bi, respectively. (Author)

Electrical properties of cadmium telluride films doped with antimony

International Nuclear Information System (INIS)

Atdaev, B.S.; Garyagdyev, G.; Grin', V.F.; Noskov, A.I.

1989-01-01

Effect of cadmium telluride doping with antimony on electric and photoelectric properties is investigated. Temperature dependence of dark (σ d ) and photoconductivity (σ p ) during excitation from the range of proper absorption in the temperature range 77-300 K and spectral distribution of photoconductivity at 300 K are investigated. It is shown that in the process of doping antimony diffusses intensively over CdTe grain boundaries, decreasing potential barriers between them and due to diffusion into CdTe grains it changes their electrical properties. The acceptor character of antimony impurity can be caused by antimony diffusion into tellurium sublattice owing to proximity of their ionic and covalent radii

Comparison of properties of silver-metal oxide electrical contact materials

Directory of Open Access Journals (Sweden)

Ćosović V.

2012-01-01

Full Text Available Changes in physical properties such as density, porosity, hardness and electrical conductivity of the Ag-SnO2 and Ag-SnO2In2O3 electrical contact materials induced by introduction of metal oxide nanoparticles were investigated. Properties of the obtained silver-metal oxide nanoparticle composites are discussed and presented in comparison to their counterparts with the micro metal oxide particles as well as comparable Ag-SnO2WO3 and Ag-ZnO contact materials. Studied silvermetal oxide composites were produced by powder metallurgy method from very fine pure silver and micro- and nanoparticle metal oxide powders. Very uniform microstructures were obtained for all investigated composites and they exhibited physical properties that are comparable with relevant properties of equivalent commercial silver based electrical contact materials. Both Ag-SnO2 and Ag- SnO2In2O3 composites with metal oxide nanoparticles were found to have lower porosity, higher density and hardness than their respective counterparts which can be attributed to better dispersion hardening i.e. higher degree of dispersion of metal oxide in silver matrix.

Electrical Transport Ability of Nanostructured Potassium-Doped Titanium Oxide Film

Science.gov (United States)

Lee, So-Yoon; Matsuno, Ryosuke; Ishihara, Kazuhiko; Takai, Madoka

2011-02-01

Potassium-doped nanostructured titanium oxide films were fabricated using a wet corrosion process with various KOH solutions. The doped condition of potassium in TiO2 was confirmed by Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). Nanotubular were synthesized at a dopant concentration of 0.27%, these structures disappeared. To investigate the electrical properties of K-doped TiO2, pseudo metal-oxide-semiconductor field-effect transistor (MOSFET) samples were fabricated. The samples exhibited a distinct electrical behavior and p-type characteristics. The electrical behavior was governed by the volume of the dopant when the dopant concentration was 0.18%.

Effects of applied dc radial electric fields on particle transport in a bumpy torus plasma

Science.gov (United States)

Roth, J. R.

1978-01-01

The influence of applied dc radial electric fields on particle transport in a bumpy torus plasma is studied. The plasma, magnetic field, and ion heating mechanism are operated in steady state. Ion kinetic temperature is more than a factor of ten higher than electron temperature. The electric fields raise the ions to energies on the order of kilovolts and then point radially inward or outward. Plasma number density profiles are flat or triangular across the plasma diameter. It is suggested that the radial transport processes are nondiffusional and dominated by strong radial electric fields. These characteristics are caused by the absence of a second derivative in the density profile and the flat electron temperature profiles. If the electric field acting on the minor radius of the toroidal plasma points inward, plasma number density and confinement time are increased.

Radial electric field and transport near the rational surface and the magnetic island in LHD

International Nuclear Information System (INIS)

Ida, K.; Inagaki, S.; Tamura, N.

2002-10-01

The structure of the radial electric field and heat transport at the magnetic island in the Large Helical Device is investigated by measuring the radial profile of poloidal flow with charge exchange spectroscopy. The convective poloidal flow inside the island is observed when the n/m=1/1 external perturbation field becomes large enough to increase the magnetic island width above a critical value (15-20% of minor radius) in LHD. This convective poloidal flow results in a non-flat space potential inside the magnetic island. The sign of the curvature of the space potential depends on the radial electric field at the boundary of the magnetic island. The heat transport inside the magnetic island is studied with a cold pulse propagation technique. The experimental results show the existence of the radial electric field shear at the boundary of the magnetic island and a reduction of heat transport inside the magnetic island. (author)

Influence of substitutional disorder on the electrical transport and the superconducting properties of Fe1+zTe1−x−ySexSy

International Nuclear Information System (INIS)

Rodríguez, M.G.; Polla, G.; Ramos, C.P.; Acha, C.

2015-01-01

We have carried out an investigation of the structural, magnetic, transport and superconducting properties of Fe 1+z Te 1−x−y Se x S y ceramic compounds, for z = 0 and some specific Se (0 ≤ x ≤ 0.5) and S (0 ≤ y ≤ 0.12) contents. The incorporation of Se and S to the FeTe structure produces a progressive reduction of the crystallographic parameters as well as different degrees of structural disorder associated with the differences of the ionic radius of the substituting cations. In the present study, we measure transport properties of this family of compounds and we show the direct influence of disorder in the normal and superconductor states. We notice that the structural disorder correlates with a variable range hopping conducting regime observed at temperatures T > 200 K. At lower temperatures, all the samples except the one with the highest degree of disorder show a crossover to a metallic-like regime, probably related to the transport of resilient-quasi-particles associated with the proximity of a Fermi liquid state at temperatures below the superconducting transition. Moreover, the superconducting properties are depressed only for that particular sample, in accordance to the condition that superconductivity is affected by disorder when the electronic localization length ξ L becomes smaller than the coherence length ξ SC . - Highlights: • New Fe(1 + z)Te(1−x−y)Se(x)S(y) ceramic samples were synthesized. • Structural, magnetic, transport and superconducting properties are presented. • Nonmagnetic disorder determines a VRH conduction regime near room temperature. • Superconductivity is affected by disorder

Electronic and thermoelectric properties of InN studied using ab initio density functional theory and Boltzmann transport calculations

Energy Technology Data Exchange (ETDEWEB)

Borges, P. D., E-mail: pdborges@gmail.com, E-mail: lscolfaro@txstate.edu; Scolfaro, L., E-mail: pdborges@gmail.com, E-mail: lscolfaro@txstate.edu [Department of Physics, Texas State University, San Marcos, Texas 78666 (United States)

2014-12-14

The thermoelectric properties of indium nitride in the most stable wurtzite phase (w-InN) as a function of electron and hole concentrations and temperature were studied by solving the semiclassical Boltzmann transport equations in conjunction with ab initio electronic structure calculations, within Density Functional Theory. Based on maximally localized Wannier function basis set and the ab initio band energies, results for the Seebeck coefficient are presented and compared with available experimental data for n-type as well as p-type systems. Also, theoretical results for electric conductivity and power factor are presented. Most cases showed good agreement between the calculated properties and experimental data for w-InN unintentionally and p-type doped with magnesium. Our predictions for temperature and concentration dependences of electrical conductivity and power factor revealed a promising use of InN for intermediate and high temperature thermoelectric applications. The rigid band approach and constant scattering time approximation were utilized in the calculations.

Surface morphology, structural and electrical properties of RF ...

Indian Academy of Sciences (India)

5

electrical properties of RF sputtered ITO thin films deposited onto Si(100). .... scanning electron microscopy (SEM) surface images are shown along with the cross- ..... annealing effect”, J. of Alloys and Compounds 509, (2011) 6072-6076.