WorldWideScience

Sample records for carrier mobility

  1. Solid state cloaking for electrical charge carrier mobility control

    Science.gov (United States)

    Zebarjadi, Mona; Liao, Bolin; Esfarjani, Keivan; Chen, Gang

    2015-07-07

    An electrical mobility-controlled material includes a solid state host material having a controllable Fermi energy level and electrical charge carriers with a charge carrier mobility. At least one Fermi level energy at which a peak in charge carrier mobility is to occur is prespecified for the host material. A plurality of particles are distributed in the host material, with at least one particle disposed with an effective mass and a radius that minimize scattering of the electrical charge carriers for the at least one prespecified Fermi level energy of peak charge carrier mobility. The minimized scattering of electrical charge carriers produces the peak charge carrier mobility only at the at least one prespecified Fermi level energy, set by the particle effective mass and radius, the charge carrier mobility being less than the peak charge carrier mobility at Fermi level energies other than the at least one prespecified Fermi level energy.

  2. High carrier mobilities in black diamond

    Science.gov (United States)

    Williams, Oliver A.; Jackman, Richard B.; Nebel, Christoph; Foord, John S.

    2003-03-01

    Hydrogen plasma treatment of diamond renders the surface p-type, with the carriers emerging with little thermal activation, in sharp contrast to the use of boron for the formation of p-type material. To date, it has been thought that only the highest quality 'white' polycrystalline material is useful for electronic device applications, with many regarding single-crystal diamond as ultimately the substrate material of choice. In this paper it is shown that when p-type material is produced through hydrogenation, this is not the case. 'Black' polycrystalline diamond, which can be grown much more rapidly than white, shows carrier concentrations and mobility values similar to both white polycrystalline diamond and single-crystal material. This result has important implications for the provision of low-cost black-diamond substrates for device applications.

  3. Carbon phosphide monolayers with superior carrier mobility

    Science.gov (United States)

    Wang, Gaoxue; Pandey, Ravindra; Karna, Shashi P.

    2016-04-01

    Two dimensional (2D) materials with a finite band gap and high carrier mobility are sought after materials from both fundamental and technological perspectives. In this paper, we present the results based on the particle swarm optimization method and density functional theory which predict three geometrically different phases of the carbon phosphide (CP) monolayer consisting of sp2 hybridized C atoms and sp3 hybridized P atoms in hexagonal networks. Two of the phases, referred to as α-CP and β-CP with puckered or buckled surfaces are semiconducting with highly anisotropic electronic and mechanical properties. More remarkably, they have the lightest electrons and holes among the known 2D semiconductors, yielding superior carrier mobility. The γ-CP has a distorted hexagonal network and exhibits a semi-metallic behavior with Dirac cones. These theoretical findings suggest that the binary CP monolayer is a yet unexplored 2D material holding great promise for applications in high-performance electronics and optoelectronics.Two dimensional (2D) materials with a finite band gap and high carrier mobility are sought after materials from both fundamental and technological perspectives. In this paper, we present the results based on the particle swarm optimization method and density functional theory which predict three geometrically different phases of the carbon phosphide (CP) monolayer consisting of sp2 hybridized C atoms and sp3 hybridized P atoms in hexagonal networks. Two of the phases, referred to as α-CP and β-CP with puckered or buckled surfaces are semiconducting with highly anisotropic electronic and mechanical properties. More remarkably, they have the lightest electrons and holes among the known 2D semiconductors, yielding superior carrier mobility. The γ-CP has a distorted hexagonal network and exhibits a semi-metallic behavior with Dirac cones. These theoretical findings suggest that the binary CP monolayer is a yet unexplored 2D material holding great

  4. Radial dependence of the carrier mobility in semiconductor nanowires

    International Nuclear Information System (INIS)

    The mobility of charge carriers in a semiconductor nanowire is explored as a function of increasing radius, assuming low temperatures where impurity scattering dominates. The competition between increased cross-section and the concurrent increase in available scattering channels causes strongly non-monotonic dependence of the mobility on the radius. The inter-band scattering causes sharp declines in the mobility at the wire radii at which each new channel becomes available. At intermediate radii with the number of channels unchanged the mobility is seen to maintain an exponential growth even with multiple channels. We also compare the effects of changing the radial scaling of the impurity distribution. We use transverse carrier wavefunctions that are consistent with boundary conditions and demonstrate that the δ-function approximate transverse profile leads to errors in the case of remote impurities

  5. Charge carrier mobility in cationic polythiophene polyelectrolyte

    Czech Academy of Sciences Publication Activity Database

    Kazim, Samrana; Rais, David; Pfleger, Jiří; Bondarev, D.; Vohlídal, J.

    Kanpur : Indian Institute of Technology, 2011. OE-P.20. [International Workshop on the Physics of Semiconductor Devices /16./ - IWPSD 2011. 19.12.2011-22.12.2011, Kanpur] R&D Projects: GA ČR GAP208/10/0941 EU Projects: European Commission(XE) 247745 - FlexNet Institutional research plan: CEZ:AV0Z40500505 Keywords : CELIV * TOF * mobility Subject RIV: CF - Physical ; Theoretical Chemistry

  6. Carrier mobility characterization of DNA-surfactant complexes

    Science.gov (United States)

    Lin, Ting-Yu; Hung, Yu-Chueh

    2012-02-01

    Deoxyribonucleic acid (DNA) biopolymer has been emerging as a promising material for photonic applications. As many optoelectronic devices rely on carrier transportation to achieve desired functionality, carrier mobility is important for the exploitation of these biopolymer-based materials for practical implementation. In this study, we present the mobility measurement by employing time-of-flight technique and characterize the current-voltage (I-V) properties based on DNA-surfactant complexes. An additional NPB layer was introduced in the fabricated structure to serve as a charge generation layer (CGL). The dependency of hole mobility with respect to the applied electric field was characterized and a linear correlation was exhibited. Hole transport was found to be dispersive, indicating a high degree energetic disorder in these DNA-surfactant complexes. The characterization results show promises for the employment of DNA complexes in the applications of organic light-emitting devices and organic field-effect transistors.

  7. 77 FR 14012 - Eligible Telecommunications Carrier Designation for Participation in Mobility Fund Phase I

    Science.gov (United States)

    2012-03-08

    ... Telecommunications Carrier Designation for Participation in Mobility Fund Phase I AGENCY: Federal Communications Commission. ACTION: Notice. SUMMARY: In this document, the Commission's Wireless Telecommunications and... Telecommunications Carrier (ETC) Designation from the Commission for participation in Mobility Fund Phase I...

  8. Pressure effect on charge carrier mobility in SmS

    International Nuclear Information System (INIS)

    Dependences of the charge carrier mobility on the pressure of hydrostatic compression for samarium monosulfide minocrystals and some solid solutions on its base in the pressure range from the atmospheric to critical pressures of the semiconductor-metal phase transition at T=300K are investigated. The behaviour of the factor in SmS under pressure is calculated from the experimental data on the pressure dependence of the Hall constant and thermo-e.m.f

  9. Intrinsic Charge Carrier Mobility in Single-Layer Black Phosphorus.

    Science.gov (United States)

    Rudenko, A N; Brener, S; Katsnelson, M I

    2016-06-17

    We present a theory for single- and two-phonon charge carrier scattering in anisotropic two-dimensional semiconductors applied to single-layer black phosphorus (BP). We show that in contrast to graphene, where two-phonon processes due to the scattering by flexural phonons dominate at any practically relevant temperatures and are independent of the carrier concentration n, two-phonon scattering in BP is less important and can be considered negligible at n≳10^{13}  cm^{-2}. At smaller n, however, phonons enter in the essentially anharmonic regime. Compared to the hole mobility, which does not exhibit strong anisotropy between the principal directions of BP (μ_{xx}/μ_{yy}∼1.4 at n=10^{13} cm^{-2} and T=300  K), the electron mobility is found to be significantly more anisotropic (μ_{xx}/μ_{yy}∼6.2). Absolute values of μ_{xx} do not exceed 250 (700)  cm^{2} V^{-1} s^{-1} for holes (electrons), which can be considered as an upper limit for the mobility in BP at room temperature. PMID:27367397

  10. Carrier mobility and crystal perfection of tetracene thin film FET

    International Nuclear Information System (INIS)

    It is well-known that the carrier mobility of an organic field effect semiconductor (FET) depended on the crystal quality and/or the crystal perfection of the organic thin films [T.W. Kelly, D.V. Muyres, P.F. Baude, T.P. Smith, T.D. Jones, Mater. Res. Soc. Symp. Proc. 771 (2003) L6.5.1; D.J. Gundlach, J.A. Nichols, L. Zhou, T.N. Jackson, Appl. Phys. Lett. 80 (2002) 2925; H.K. Lauk, M. Halik, U. Zschieschang, G. Schmid, W. Radlik, J. Appl. Phys. 92 (2002) 5259; M. Shtein, J. Mapel, J.B. Benziger, S.R. Forrest, Appl. Phys. Lett. 81 (2002) 268; D. Knipp, R.A. Street, A.R. Volkel, Appl. Phys. Lett. 82 (2003) 3907; R. Ruiz, A.C. Mayer, G.G. Malliaras, Appl. Phys. Lett. 85 (2004) 4926; R.W.I. de Boer, M.E. Gershenson, A.F. Morpurgo, V. Podzorov, Phys. Stat. Sol. A 201 (2004) 1031]. To improve the crystal quality of the thin film many efforts were made. One of the important improvements was the surface treatment of the substrate. The tetracene thin film FET (top contact structure) was fabricated using the substrate, which was coated by a spin-coating method with a 0.1% poly α-methylstyrene (AMS) solution. The crystal quality was improved by this treatment so that the carrier mobility was higher than that of non-treatment. The maximum mobility of the AMS-treated sample was obtained to be 0.12 cm2/V s

  11. Columnar mesophases of hexabenzocoronene derivatives. II. Charge carrier mobility.

    Science.gov (United States)

    Kirkpatrick, James; Marcon, Valentina; Kremer, Kurt; Nelson, Jenny; Andrienko, Denis

    2008-09-01

    Combining atomistic molecular dynamic simulations, Marcus-Hush theory description of charge transport rates, and master equation description of charge dynamics, we correlate the temperature-driven change of the mesophase structure with the change of charge carrier mobilities in columnar phases of hexabenzocoronene derivatives. The time dependence of fluctuations in transfer integrals shows that static disorder is predominant in determining charge transport characteristics. Both site energies and transfer integrals are distributed because of disorder in the molecular arrangement. It is shown that the contributions to the site energies from polarization and electrostatic effects are of opposite sign for positive charges. We look at three mesophases of hexabenzocoronene: herringbone, discotic, and columnar disordered. All results are compared to time resolved microwave conductivity data and show excellent agreement with no fitting parameters. PMID:19044876

  12. Giant Carrier Mobility in Single Crystals of FeSb2

    OpenAIRE

    Hu, Rongwei; Mitrovic, V. F.; Petrovic, C

    2008-01-01

    We report the giant carrier mobility in single crystals of FeSb2. Nonlinear field dependence of Hall resistivity is well described with the two-carrier model. Maximum mobility values in high mobility band reach ~10^5 cm^2/Vs at 8 K, and are ~10^2 cm^2/Vs at the room temperature. Our results point to a class of materials with promising potential for applications in solid state electronics.

  13. Mobility Analysis for Inter-Site Carrier Aggregation in LTE Heterogeneous Networks

    DEFF Research Database (Denmark)

    Barbera, Simone; Pedersen, Klaus I.; Michaelsen, Per Henrik; Rosa, Claudio

    In this paper we analyze the mobility performance for an LTE Heterogeneous Network with macro and pico cells deployed on different carriers. Cases with/without downlink inter-site carrier aggregation are investigated. Extensive system level simulations are exploited to quantify the performance. It...

  14. Unified description of charge-carrier mobilities in disordered semiconducting polymers

    NARCIS (Netherlands)

    Pasveer, WF; Cottaar, J; Tanase, C; Coehoorn, R; Bobbert, PA; Blom, PWM; de Leeuw, DM; Michels, MAJ

    2005-01-01

    From a numerical solution of the master equation for hopping transport in a disordered energy landscape with a Gaussian density of states, we determine the dependence of the charge-carrier mobility on temperature, carrier density, and electric field. Experimental current-voltage characteristics in d

  15. Unified Description of Charge-Carrier Mobilities in Disordered Semiconducting Polymers

    NARCIS (Netherlands)

    Pasveer, W.F.; Cottaar, J.; Tanase, C.; Coehoorn, R.; Bobbert, P.A.; Blom, P.W.M.; De Leeuw, D.M.; Michels, M.A.J.

    2005-01-01

    From a numerically exact solution of the Master equation for hoppingtransport in a disordered energy landscape with a Gaussian densityof states, we determine the dependence on temperature, carrier density, and electric field of the charge carrier mobility. Experimentalspace-charge limited currents i

  16. Charge carrier mobility in phthalocyanines: Experiment and quantum chemical calculations

    Czech Academy of Sciences Publication Activity Database

    Kratochvílová, Irena

    Rijeka : InTech, 2012 - (Tada, T.), s. 159-174 ISBN 978-953-51-0372-1 R&D Projects: GA ČR(CZ) GAP304/10/1951 Institutional research plan: CEZ:AV0Z10100520 Keywords : phtalocyanines * DFT * charge mobility Subject RIV: BM - Solid Matter Physics ; Magnetism http://www.intechopen.com/books/quantum-chemistry-molecules-for-innovations

  17. A self-consistent first-principle based approach to model carrier mobility in organic materials

    Science.gov (United States)

    Meded, Velimir; Friederich, Pascal; Symalla, Franz; Neumann, Tobias; Danilov, Denis; Wenzel, Wolfgang

    2015-12-01

    Transport through thin organic amorphous films, utilized in OLEDs and OPVs, has been a challenge to model by using ab-initio methods. Charge carrier mobility depends strongly on the disorder strength and reorganization energy, both of which are significantly affected by the details in environment of each molecule. Here we present a multi-scale approach to describe carrier mobility in which the materials morphology is generated using DEPOSIT, a Monte Carlo based atomistic simulation approach, or, alternatively by molecular dynamics calculations performed with GROMACS. From this morphology we extract the material specific hopping rates, as well as the on-site energies using a fully self-consistent embedding approach to compute the electronic structure parameters, which are then used in an analytic expression for the carrier mobility. We apply this strategy to compute the carrier mobility for a set of widely studied molecules and obtain good agreement between experiment and theory varying over several orders of magnitude in the mobility without any freely adjustable parameters. The work focuses on the quantum mechanical step of the multi-scale workflow, explains the concept along with the recently published workflow optimization, which combines density functional with semi-empirical tight binding approaches. This is followed by discussion on the analytic formula and its agreement with established percolation fits as well as kinetic Monte Carlo numerical approaches. Finally, we skatch an unified multi-disciplinary approach that integrates materials science simulation and high performance computing, developed within EU project MMM@HPC.

  18. A self-consistent first-principle based approach to model carrier mobility in organic materials

    Energy Technology Data Exchange (ETDEWEB)

    Meded, Velimir; Friederich, Pascal; Symalla, Franz; Neumann, Tobias; Danilov, Denis; Wenzel, Wolfgang [Institute of Nanotechnology, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany)

    2015-12-31

    Transport through thin organic amorphous films, utilized in OLEDs and OPVs, has been a challenge to model by using ab-initio methods. Charge carrier mobility depends strongly on the disorder strength and reorganization energy, both of which are significantly affected by the details in environment of each molecule. Here we present a multi-scale approach to describe carrier mobility in which the materials morphology is generated using DEPOSIT, a Monte Carlo based atomistic simulation approach, or, alternatively by molecular dynamics calculations performed with GROMACS. From this morphology we extract the material specific hopping rates, as well as the on-site energies using a fully self-consistent embedding approach to compute the electronic structure parameters, which are then used in an analytic expression for the carrier mobility. We apply this strategy to compute the carrier mobility for a set of widely studied molecules and obtain good agreement between experiment and theory varying over several orders of magnitude in the mobility without any freely adjustable parameters. The work focuses on the quantum mechanical step of the multi-scale workflow, explains the concept along with the recently published workflow optimization, which combines density functional with semi-empirical tight binding approaches. This is followed by discussion on the analytic formula and its agreement with established percolation fits as well as kinetic Monte Carlo numerical approaches. Finally, we skatch an unified multi-disciplinary approach that integrates materials science simulation and high performance computing, developed within EU project MMM@HPC.

  19. A self-consistent first-principle based approach to model carrier mobility in organic materials

    International Nuclear Information System (INIS)

    Transport through thin organic amorphous films, utilized in OLEDs and OPVs, has been a challenge to model by using ab-initio methods. Charge carrier mobility depends strongly on the disorder strength and reorganization energy, both of which are significantly affected by the details in environment of each molecule. Here we present a multi-scale approach to describe carrier mobility in which the materials morphology is generated using DEPOSIT, a Monte Carlo based atomistic simulation approach, or, alternatively by molecular dynamics calculations performed with GROMACS. From this morphology we extract the material specific hopping rates, as well as the on-site energies using a fully self-consistent embedding approach to compute the electronic structure parameters, which are then used in an analytic expression for the carrier mobility. We apply this strategy to compute the carrier mobility for a set of widely studied molecules and obtain good agreement between experiment and theory varying over several orders of magnitude in the mobility without any freely adjustable parameters. The work focuses on the quantum mechanical step of the multi-scale workflow, explains the concept along with the recently published workflow optimization, which combines density functional with semi-empirical tight binding approaches. This is followed by discussion on the analytic formula and its agreement with established percolation fits as well as kinetic Monte Carlo numerical approaches. Finally, we skatch an unified multi-disciplinary approach that integrates materials science simulation and high performance computing, developed within EU project MMM@HPC

  20. Effect of ferroelectric substrate on carrier mobility in graphene field-effect transistors

    Science.gov (United States)

    Bidmeshkipour, S.; Vorobiev, A.; Andersson, M. A.; Kompany, A.; Stake, J.

    2015-10-01

    Effect of LiNbO3 ferroelectric substrate on the carrier mobility in top gated graphene field-effect transistors (G-FETs) is demonstrated. It is shown that, at the same residual concentration of the charge carriers, the mobility in the G-FETs on the LiNbO3 substrate is higher than that on the SiO2/Si substrate. The effect is associated with reduction of Coulomb scattering via screening the charged impurity field by the field induced in the ferroelectric substrate, but significant only for mobilities below 1000 cm2/V s. Raman spectra analysis and correlations established between mobility and microwave loss tangent of the Al2O3 gate dielectric indicate that the charged impurities are located predominantly at the gate dielectric and/or at the gate dielectric/graphene interface and are likely associated with oxygen vacancies.

  1. Determination of charge carrier mobility in doped low density polyethylene using DC transients

    DEFF Research Database (Denmark)

    Khalil, M.Salah; Henk, Peter O; Henriksen, Mogens

    1989-01-01

    Charge carrier mobility was determined for plain and doped low-density polyethylene (LDPE) using DC transient currents. Barium titanate was used as a strongly polar dopant and titanium dioxide as a semiconductor dopant. The values of the mobility obtained were on the order of 10-10 cm2 v-1 s-1...... a factor of five. Charge trapping and space charge formation were modified by the introduction of titanium dioxide...

  2. Estimation of carrier mobility at organic semiconductor/insulator interface using an asymmetric capacitive test structure

    OpenAIRE

    Rajesh Agarwal; Ashish K. Agarwal; Baquer Mazhari

    2016-01-01

    Mobility of carriers at the organic/insulator interface is crucial to the performance of organic thin film transistors. The present work describes estimation of mobility using admittance measurements performed on an asymmetric capacitive test structure. Besides the advantage of simplicity, it is shown that at low frequencies, the measured capacitance comes from a large area of channel making the capacitance-voltage characteristics insensitive to contact resistances. 2-D numerical simulation a...

  3. Large enhancements of thermopower and carrier mobility in quantum dot engineered bulk semiconductors.

    Science.gov (United States)

    Liu, Yuanfeng; Sahoo, Pranati; Makongo, Julien P A; Zhou, Xiaoyuan; Kim, Sung-Joo; Chi, Hang; Uher, Ctirad; Pan, Xiaoqing; Poudeu, Pierre F P

    2013-05-22

    The thermopower (S) and electrical conductivity (σ) in conventional semiconductors are coupled adversely through the carriers' density (n) making it difficult to achieve meaningful simultaneous improvements in both electronic properties through doping and/or substitutional chemistry. Here, we demonstrate the effectiveness of coherently embedded full-Heusler (FH) quantum dots (QDs) in tailoring the density, mobility, and effective mass of charge carriers in the n-type Ti(0.1)Zr(0.9)NiSn half-Heusler matrix. We propose that the embedded FH QD forms a potential barrier at the interface with the matrix due to the offset of their conduction band minima. This potential barrier discriminates existing charge carriers from the conduction band of the matrix with respect to their relative energy leading to simultaneous large enhancements of the thermopower (up to 200%) and carrier mobility (up to 43%) of the resulting Ti(0.1)Zr(0.9)Ni(1+x)Sn nanocomposites. The improvement in S with increasing mole fraction of the FH-QDs arises from a drastic reduction (up to 250%) in the effective carrier density coupled with an increase in the carrier's effective mass (m*), whereas the surprising enhancement in the mobility (μ) is attributed to an increase in the carrier's relaxation time (τ). This strategy to manipulate the transport behavior of existing ensembles of charge carriers within a bulk semiconductor using QDs is very promising and could pave the way to a new generation of high figure of merit thermoelectric materials. PMID:23607819

  4. Study of carrier mobility of tubular and planar graphdiyne

    Science.gov (United States)

    Jalili, Seifollah; Houshmand, Fatemeh; Schofield, Jeremy

    2015-05-01

    Graphdiyne nanotubes were constructed 10 years after their theoretical prediction and many properties of them have remained unknown until now. In this investigation, transport properties of new family of carbon nanotubes, graphdiyne nanotubes, were studied systematically by using spin-polarized density functional theory coupled with Boltzmann transport equation with relaxation time approximation. We have predicted the charge mobility for tubular forms of graphdiyne (GDNT). The calculated intrinsic electron mobility for GDNT at room temperature can reach the order of 104 cm2 V-1 s-1. On the other hand, the hole mobility magnitude is about an order of 102 cm2 V-1 s-1. The DFT results also show that GDNT is direct band-gap semiconductor. The calculated cohesive and strain energies for GDNT indicate that this new nanomaterial is more stable than the conventional carbon nanotubes. Adsorption of a transition metal atom (Fe) on the external surface of GDNT has been studied by DFT method as well as density functional theory plus effective on-site Coulomb repulsion parameters U, Hubbard correction. Transition metal (TM)-adsorbed GDNT is magnetic and shows semimetal property. Charge transfer between TM adatom and GDNT as well as the electron redistribution of the TM intra-atomic s, p and d orbitals indicates that the TM-adsorbed single-walled γ-graphdiyne have a high potential for applications in spintronics and in future optoelectronics. The single-layer nanostructure of graphdiyne (pGD) is studied too. The resulted electronic properties of pGD and TM-absorbed-pGD confirm previous results for these nanostructures. Also, transport properties of stable TM-pGD nanostructure as well as TM-GDNT are notable. Energy gap values for both nanostructures are found to be strongly sensitive to the local Coulomb interactions U of the TM d orbitals.

  5. Model of the charge carrier mobility in conjugated polymers containing dipolar species

    Czech Academy of Sciences Publication Activity Database

    Toman, Petr; Menšík, Miroslav

    Pisa : European Polymer Federation, 2013. O7-9. [European Polymer Congress - EPF 2013. 16.06.2013-21.06.2013, Pisa] R&D Projects: GA ČR(CZ) GAP205/10/2280 Institutional support: RVO:61389013 Keywords : charge carrier mobility * conjugated polymer * Marcus theory Subject RIV: BM - Solid Matter Physics ; Magnetism

  6. Evaluation of anisotropic charge carrier mobility of perylene single crystals by time-of-flight method

    Science.gov (United States)

    Kougo, Junichi; Ishikawa, Ken

    2016-03-01

    The charge carrier mobilities along the vertical and lateral directions of perylene platelet single crystals were measured by the time-of-flight (TOF) method. In the lateral directional measurement, the entire region between electrodes was irradiated to obtain measurable signals. The transient photocurrent was different from the conventional TOF measurements; hence, we developed an analytic method for lateral directional measurement. The electron mobilities along the thickness and lateral directions were 0.33 and 2.0 cm2·V-1·s-1 and the hole mobilities were 0.12 and 0.6 cm2·V-1·s-1, respectively.

  7. Ab initio charge-carrier mobility model for amorphous molecular semiconductors

    Science.gov (United States)

    Massé, Andrea; Friederich, Pascal; Symalla, Franz; Liu, Feilong; Nitsche, Robert; Coehoorn, Reinder; Wenzel, Wolfgang; Bobbert, Peter A.

    2016-05-01

    Accurate charge-carrier mobility models of amorphous organic molecular semiconductors are essential to describe the electrical properties of devices based on these materials. The disordered nature of these semiconductors leads to percolative charge transport with a large characteristic length scale, posing a challenge to the development of such models from ab initio simulations. Here, we develop an ab initio mobility model using a four-step procedure. First, the amorphous morphology together with its energy disorder and intermolecular charge-transfer integrals are obtained from ab initio simulations in a small box. Next, the ab initio information is used to set up a stochastic model for the morphology and transfer integrals. This stochastic model is then employed to generate a large simulation box with modeled morphology and transfer integrals, which can fully capture the percolative charge transport. Finally, the charge-carrier mobility in this simulation box is calculated by solving a master equation, yielding a mobility function depending on temperature, carrier concentration, and electric field. We demonstrate the procedure for hole transport in two important molecular semiconductors, α -NPD and TCTA. In contrast to a previous study, we conclude that spatial correlations in the energy disorder are unimportant for α -NPD. We apply our mobility model to two types of hole-only α -NPD devices and find that the experimental temperature-dependent current density-voltage characteristics of all devices can be well described by only slightly decreasing the simulated energy disorder strength.

  8. Phase transition, effective mass and carrier mobility of MoS2 monolayer under tensile strain

    International Nuclear Information System (INIS)

    We report a computational study on the impact of tensile strain on MoS2 monolayer. The transition between direct and indirect bandgap structure and the transition between semiconductor and metal phases in the monolayer have been investigated with tensile strain along all direction configurations with both x-axis and y-axis components εxy (εx and εy). Electron effective mass and the hole effective mass are isotropic for biaxial strain εxy = εx = εy and anisotropic for εxy with εx ≠ εy. The carrier effective mass behaves differently along different directions in response to the tensile strain. In addition, the impact of strain on carrier mobility has been studied by using the deformation potential theory. The electron mobility increases over 10 times with the biaxial strain: εx = εy = 9.5%. Also, the mobility decreases monotonically with the increasing temperature as μ ∼ T−1. These results are very important for future nanotechnology based on two-dimensional materials

  9. Analytical model of carrier mobility in a Polymer Field Effect Transistor

    Directory of Open Access Journals (Sweden)

    Milošević Milan M.

    2007-01-01

    Full Text Available In this paper, the carrier mobility analytical model in a POFET (Polymer Field Effect Transistor channel is proposed. The model was developed on the basis of existing models and experimental results. The proposed model is universal because it encompasses the carrier mobility dependence on temperature, electric field and trap density in the POFET channel. The model is comparatively simple, easy for application and gives valuable results. According to the presented model, simulations of mobility as a function of the parameters of interest were performed. The obtained results are shown graphically. In comparison to accessible experimental results excellent correspondence was found. This model enables the calculation of simple POFET current-voltage I (V characteristics.

  10. Encapsulating Mobile Proton Carriers into Structural Defects in Coordination Polymer Crystals: High Anhydrous Proton Conduction and Fuel Cell Application.

    Science.gov (United States)

    Inukai, Munehiro; Horike, Satoshi; Itakura, Tomoya; Shinozaki, Ryota; Ogiwara, Naoki; Umeyama, Daiki; Nagarkar, Sanjog; Nishiyama, Yusuke; Malon, Michal; Hayashi, Akari; Ohhara, Takashi; Kiyanagi, Ryoji; Kitagawa, Susumu

    2016-07-13

    We describe the encapsulation of mobile proton carriers into defect sites in nonporous coordination polymers (CPs). The proton carriers were encapsulated with high mobility and provided high proton conductivity at 150 °C under anhydrous conditions. The high proton conductivity and nonporous nature of the CP allowed its application as an electrolyte in a fuel cell. The defects and mobile proton carriers were investigated using solid-state NMR, XAFS, XRD, and ICP-AES/EA. On the basis of these analyses, we concluded that the defect sites provide space for mobile uncoordinated H3PO4, H2PO4(-), and H2O. These mobile carriers play a key role in expanding the proton-hopping path and promoting the mobility of protons in the coordination framework, leading to high proton conductivity and fuel cell power generation. PMID:27324658

  11. Electronic properties and carrier mobilities of 6,6,12-graphyne nanoribbons

    International Nuclear Information System (INIS)

    Structures, stabilities, electronic properties and carrier mobilities of 6,6,12-graphyne nanoribbons (GyNRs) with armchair and zigzag edges are investigated using the self-consistent field crystal orbital method based on density functional theory. It is found that the 1D GyNRs are more stable than the 2D 6,6,12-graphyne sheet in the view of the Gibbs free energy. The stabilities of these GyNRs decrease as their widths increase. The calculated band structures show that all these GyNRs are semiconductors and that dependence of band gaps on the ribbon width is different from different types of the GyNRs. The carrier mobility was calculated based on the deformation theory and effective mass approach. It is found that the carrier mobilities of these GyNRs can reach the order of 105 cm2 V –1s–1 at room temperature and are comparable to those of graphene NRs. Moreover, change of the mobilities with change of the ribbon width is quite different from different types of the GyNRs

  12. Home built equipment for measuring Hall coefficient and charge carrier concentration, mobility and resistivity

    DEFF Research Database (Denmark)

    Borup, Kasper Andersen; Christensen, Mogens; Blichfeld, Anders Bank; Johnsen, Simon; Toberer, Eric; Snyder, G. Jeffrey

    2011-01-01

    system, the Quantum Design, Physical Properties Measurement System (PPMS). Measurements on samples with different resistivity and charge carrier concentration will be shown, covering both ends of the interval of samples we are able to measure as well as the range normally observed for thermoelectrics......We present here a home built setup for measuring the specific resistivity, hall coefficient, and charge carrier concentration and mobility at elevated temperatures. The system is optimized for measurements of samples ranging between doped semiconductors and high resistivity metals and uses the van...

  13. 14 CFR 382.125 - What procedures do carriers follow when wheelchairs, other mobility aids, and other assistive...

    Science.gov (United States)

    2010-01-01

    ... wheelchairs, other mobility aids, and other assistive devices must be stowed in the cargo compartment? 382.125... Wheelchairs, Other Mobility Aids, and Other Assistive Devices § 382.125 What procedures do carriers follow when wheelchairs, other mobility aids, and other assistive devices must be stowed in the...

  14. The impact of occupational load carriage on carrier mobility: a critical review of the literature.

    Science.gov (United States)

    Carlton, Simon D; Orr, Robin M

    2014-01-01

    Military personnel and firefighters are required to carry occupational loads and complete tasks in hostile and unpredictable environments where a lack of mobility may risk lives. This review critically examines the literature investigating the impacts of load carriage on the mobility of these specialist personnel. Several literature databases, reference lists, and subject matter experts were employed to identify relevant studies. Studies meeting the inclusion criteria were critiqued using the Downs and Black protocol. Inter-rater agreement was determined by Cohen's κ. Twelve original research studies, which included male and female participants from military and firefighting occupations, were critiqued (κ = .81). A review of these papers found that as the carried load weight increased, carrier mobility during aerobic tasks (like road marching) and anaerobic tasks (like obstacle course negotiation) decreased. As such, it can be concluded that the load carried by some specialist personnel may increase their occupational risk by reducing their mobility. PMID:24629868

  15. Mobility enhancements for LTE-Advanced Multilayer Networks with Inter-Site Carrier Aggregation

    DEFF Research Database (Denmark)

    Pedersen, Klaus I.; Michaelsen, Per Henrik; Rosa, Claudio; Barbera, Simone

    2013-01-01

    , while using inter-site carrier aggregation, is hereafter studied. Hybrid Het- Net mobility solutions for such cases are derived, where macrocell mobility is network controlled, while small-cell mobility is made UEautonomous. The proposed scheme is characterized by having the UE devices autonomously...... decide small cell addition, removal, and change without any explicit signaling of Measurement events to the network or any signaling of hand-over commands from the network. Hence, the proposed solution effectively offloads the network from having to perform frequent small cell handoff decisions, and...... reduces the signaling overhead compared to known network controlled mobility solutions. Results from extensive dynamic system-level simulations are presented to demonstrate the advantages of the proposed technique, showing significant savings in signaling overhead....

  16. Estimation of carrier mobility at organic semiconductor/insulator interface using an asymmetric capacitive test structure

    Directory of Open Access Journals (Sweden)

    Rajesh Agarwal

    2016-04-01

    Full Text Available Mobility of carriers at the organic/insulator interface is crucial to the performance of organic thin film transistors. The present work describes estimation of mobility using admittance measurements performed on an asymmetric capacitive test structure. Besides the advantage of simplicity, it is shown that at low frequencies, the measured capacitance comes from a large area of channel making the capacitance-voltage characteristics insensitive to contact resistances. 2-D numerical simulation and experimental results obtained with Pentacene/Poly(4-vinyphenol system are presented to illustrate the operation and advantages of the proposed technique.

  17. Estimation of carrier mobility at organic semiconductor/insulator interface using an asymmetric capacitive test structure

    Science.gov (United States)

    Agarwal, Rajesh; Agarwal, Ashish K.; Mazhari, Baquer

    2016-04-01

    Mobility of carriers at the organic/insulator interface is crucial to the performance of organic thin film transistors. The present work describes estimation of mobility using admittance measurements performed on an asymmetric capacitive test structure. Besides the advantage of simplicity, it is shown that at low frequencies, the measured capacitance comes from a large area of channel making the capacitance-voltage characteristics insensitive to contact resistances. 2-D numerical simulation and experimental results obtained with Pentacene/Poly(4-vinyphenol) system are presented to illustrate the operation and advantages of the proposed technique.

  18. The Effect of Polar Fluctuation and Lattice Mismatch on Carrier Mobility at Oxide Interfaces

    OpenAIRE

    Huang, Z; Han, K.; Zeng, S. W.; Motapothula, M.; Lü, W. M.; Li, C.J.; Zhou, W. X.; Coey, J.M.D.; Venkatesan, T.; Ariando

    2015-01-01

    Since the discovery of two-dimensional electron gas (2DEG) at the oxide interface of LaAlO3/SrTiO3, improving carrier mobility has become an important issue for device applications. In this paper, by using an alternate polar perovskite insulator (La0.3Sr0.7)(Al0.65Ta0.35)O3 (LSAT) for reducing lattice mismatch from 3.0% to 1.0%, the low-temperature carrier mobility has been increased 30 fold to 35,000 cm2V-1s-1. Moreover, two critical thicknesses for the LSAT/SrTiO3 (001) interface are found:...

  19. The Effect of Polar Fluctuation and Lattice Mismatch on Carrier Mobility at Oxide Interfaces.

    Science.gov (United States)

    Huang, Zhen; Han, Kun; Zeng, Shengwei; Motapothula, Mallikarjuna; Borisevich, Albina Y; Ghosh, Saurabh; Lü, Weiming; Li, Changjian; Zhou, Wenxiong; Liu, Zhiqi; Coey, Michael; Venkatesan, T; Ariando

    2016-04-13

    Since the discovery of two-dimensional electron gas (2DEG) at the oxide interface of LaAlO3/SrTiO3 (LAO/STO), improving carrier mobility has become an important issue for device applications. In this paper, by using an alternate polar perovskite insulator (La0.3Sr0.7) (Al0.65Ta0.35)O3 (LSAT) for reducing lattice mismatch from 3.0% to 1.0%, the low-temperature carrier mobility has been increased 30 fold to 35,000 cm(2) V(-1) s(-1). Moreover, two critical thicknesses for the LSAT/STO (001) interface are found, one at 5 unit cells for appearance of the 2DEG and the other at 12 unit cells for a peak in the carrier mobility. By contrast, the conducting (110) and (111) LSAT/STO interfaces only show a single critical thickness of 8 unit cells. This can be explained in terms of polar fluctuation arising from LSAT chemical composition. In addition to lattice mismatch and crystal symmetry at the interface, polar fluctuation arising from composition has been identified as an important variable to be tailored at the oxide interfaces to optimize the 2DEG transport. PMID:26959195

  20. Glass transition dynamics and charge carrier mobility in conjugated polyfluorene thin films

    Science.gov (United States)

    Qin, Hui; Liu, Dan; Wang, Tao

    Conjugated polymers are commonly used in organic optoelectronic devices, e.g. organic photovoltaics (OPVs), light-emitting diodes (LEDs) and field effect transistors (FETs). In these devices, the conjugated polymers are prepared as thin films with thicknesses in the range of tens to hundreds of nanometers, and are interfaced with different function layers made from organic or inorganic materials. We have studied the glass transition temperature (Tg) of poly(9, 9-dioctylfluorene)-co-N-(1, 4-butylphenyl)diphenylamine) (TFB) thin films supported on different substrates, as well as their SCLC charge carrier mobility in photodiodes. Both Monotonic and non-monotonic Tg deviations are observed in TFB thin films supported on Si/SiOx and PEDOT:PSS, respectively. With low to moderate thermal crosslinking, the thickness dependent Tg deviation still exists, which diminishes in TFB films with a high crosslinking degree. The vertical charge carrier mobility of TFB thin films extracted from the SCLC measurements is found increase with film thickness, a value increases from 1 to 50 x 10-6 cm2 V-1 s-1 in the thickness range from 15 to 180 nm. Crosslinking was found to reduce the carrier mobility in TFB thin films. The Tg deviations are also discussed using the classic layered models in the literature. Our results provide a precise guide for the fabrication and design of high performance optoelectronic devices.

  1. Structure, ionic Conductivity and mobile Carrier Density in Fast Ionic Conducting Chalcogenide Glasses

    International Nuclear Information System (INIS)

    This thesis consists of six sections. The first section gives the basic research background on the ionic conduction mechanism in glass, polarization in the glass, and the method of determining the mobile carrier density in glass. The proposed work is also included in this section. The second section is a paper that characterizes the structure of MI + M2S + (0.1 Ga2S3 + 0.9 GeS2) (M = Li, Na, K and Cs) glasses using Raman and IR spectroscopy. Since the ionic radius plays an important role in determining the ionic conductivity in glasses, the glass forming range for the addition of different alkalis into the basic glass forming system 0.1 Ga2S3 + 0.9 GeS2 was studied. The study found that the change of the alkali radius for the same nominal composition causes significant structure change to the glasses. The third section is a paper that investigates the ionic conductivity of MI + M2S + (0.1Ga2S3 + 0.9 GeS2) (M = Li, Na, K and Cs) glasses system. Corresponding to the compositional changes in these fast ionic conducting glasses, the ionic conductivity shows changes due to the induced structural changes. The ionic radius effect on the ionic conductivity in these glasses was investigated. The fourth section is a paper that examines the mobile carrier density based upon the measurements of space charge polarization. For the first time, the charge carrier number density in fast ionic conducting chalcogenide glasses was determined. The experimental impedance data were fitted using equivalent circuits and the obtained parameters were used to determine the mobile carrier density. The influence of mobile carrier density and mobility on the ionic conductivity was separated. The fifth section is a paper that studies the structures of low-alkali-content Na2S + B2S3 (x (le) 0.2) glasses by neutron and synchrotron x-ray diffraction. Similar results were obtained both in neutron and synchrotron x-ray diffraction experiments. The results provide direct structural evidence that doping

  2. Structure, ionic Conductivity and mobile Carrier Density in Fast Ionic Conducting Chalcogenide Glasses

    Energy Technology Data Exchange (ETDEWEB)

    Wenlong Yao

    2006-12-12

    This thesis consists of six sections. The first section gives the basic research background on the ionic conduction mechanism in glass, polarization in the glass, and the method of determining the mobile carrier density in glass. The proposed work is also included in this section. The second section is a paper that characterizes the structure of MI + M{sub 2}S + (0.1 Ga{sub 2}S{sub 3} + 0.9 GeS{sub 2}) (M = Li, Na, K and Cs) glasses using Raman and IR spectroscopy. Since the ionic radius plays an important role in determining the ionic conductivity in glasses, the glass forming range for the addition of different alkalis into the basic glass forming system 0.1 Ga{sub 2}S{sub 3} + 0.9 GeS{sub 2} was studied. The study found that the change of the alkali radius for the same nominal composition causes significant structure change to the glasses. The third section is a paper that investigates the ionic conductivity of MI + M{sub 2}S + (0.1Ga{sub 2}S{sub 3} + 0.9 GeS{sub 2}) (M = Li, Na, K and Cs) glasses system. Corresponding to the compositional changes in these fast ionic conducting glasses, the ionic conductivity shows changes due to the induced structural changes. The ionic radius effect on the ionic conductivity in these glasses was investigated. The fourth section is a paper that examines the mobile carrier density based upon the measurements of space charge polarization. For the first time, the charge carrier number density in fast ionic conducting chalcogenide glasses was determined. The experimental impedance data were fitted using equivalent circuits and the obtained parameters were used to determine the mobile carrier density. The influence of mobile carrier density and mobility on the ionic conductivity was separated. The fifth section is a paper that studies the structures of low-alkali-content Na{sub 2}S + B{sub 2}S{sub 3} (x {le} 0.2) glasses by neutron and synchrotron x-ray diffraction. Similar results were obtained both in neutron and synchrotron x

  3. Tuning carrier mobility without spin transport degrading in copper-phthalocyanine

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, S. W.; Wang, P.; Chen, B. B.; Zhou, Y. [National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, 22 Hankou Road, Nanjing 210093 (China); Ding, H. F., E-mail: hfding@nju.edu.cn, E-mail: dwu@nju.edu.cn; Wu, D., E-mail: hfding@nju.edu.cn, E-mail: dwu@nju.edu.cn [National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, 22 Hankou Road, Nanjing 210093 (China); Collaborative Innovation Center of Advanced Microstructures, Nanjing University, 22 Hankou Road, Nanjing 210093 (China)

    2015-07-27

    We demonstrate more than one order of magnitude of carrier mobility tuning for the copper-phthalocyanine (CuPc) without spin transport degrading in organic spin valve devices. Depending on the preparation conditions, organic spin valves with the CuPc film mobility of 5.78 × 10{sup −3} and 1.11 × 10{sup −4} cm{sup 2}/V s are obtained for polycrystalline and amorphous CuPc, respectively. Strikingly, the spin diffusion lengths are almost the same regardless of their mobilities that are ∼50 times different, which is in sharp contrast with previous prediction. These findings directly support that the spin relaxation in CuPc is dominated by the spin-orbit coupling.

  4. Tuning carrier mobility without spin transport degrading in copper-phthalocyanine

    International Nuclear Information System (INIS)

    We demonstrate more than one order of magnitude of carrier mobility tuning for the copper-phthalocyanine (CuPc) without spin transport degrading in organic spin valve devices. Depending on the preparation conditions, organic spin valves with the CuPc film mobility of 5.78 × 10−3 and 1.11 × 10−4 cm2/V s are obtained for polycrystalline and amorphous CuPc, respectively. Strikingly, the spin diffusion lengths are almost the same regardless of their mobilities that are ∼50 times different, which is in sharp contrast with previous prediction. These findings directly support that the spin relaxation in CuPc is dominated by the spin-orbit coupling

  5. Charge carrier mobility and electronic properties of Al(Op3: impact of excimer formation

    Directory of Open Access Journals (Sweden)

    Andrea Magri

    2015-05-01

    Full Text Available We have studied the electronic properties and the charge carrier mobility of the organic semiconductor tris(1-oxo-1H-phenalen-9-olatealuminium(III (Al(Op3 both experimentally and theoretically. We experimentally estimated the HOMO and LUMO energy levels to be −5.93 and −3.26 eV, respectively, which were close to the corresponding calculated values. Al(Op3 was successfully evaporated onto quartz substrates and was clearly identified in the absorption spectra of both the solution and the thin film. A structured steady state fluorescence emission was detected in solution, whereas a broad, red-shifted emission was observed in the thin film. This indicates the formation of excimers in the solid state, which is crucial for the transport properties. The incorporation of Al(Op3 into organic thin film transistors (TFTs was performed in order to measure the charge carrier mobility. The experimental setup detected no electron mobility, while a hole mobility between 0.6 × 10−6 and 2.1 × 10−6 cm2·V−1·s−1 was measured. Theoretical simulations, on the other hand, predicted an electron mobility of 9.5 × 10−6 cm2·V−1·s−1 and a hole mobility of 1.4 × 10−4 cm2·V−1·s−1. The theoretical simulation for the hole mobility predicted an approximately one order of magnitude higher hole mobility than was observed in the experiment, which is considered to be in good agreement. The result for the electron mobility was, on the other hand, unexpected, as both the calculated electron mobility and chemical common sense (based on the capability of extended aromatic structures to efficiently accept and delocalize additional electrons suggest more robust electron charge transport properties. This discrepancy is explained by the excimer formation, whose inclusion in the multiscale simulation workflow is expected to bring the theoretical simulation and experiment into agreement.

  6. Thickness dependence of surface morphology and charge carrier mobility in organic field-effect transistors

    International Nuclear Information System (INIS)

    With the aim of understanding the relationships between organic small molecule field-effect transistors (FETs) and organic conjugated polymer FETs, we investigate the thickness dependence of surface morphology and charge carrier mobility in pentacene and regioregular poly (3-hexylthiophene) (RR-P3HT) field-effect transistors. On the basis of the results of surface morphologies and electrical properties, we presume that the charge carrier mobility is largely related to the morphology of the organic active layer. We observe that the change trends of the surface morphologies (average size and average roughness) of pentacene and RR-P3HT thin films are mutually opposite, as the thickness of the organic layer increases. Further, we demonstrate that the change trends of the field-effect mobilities of pentacene and RR-P3HT FETs are also opposite to each other, as the thickness of the organic layer increases within its limit. (cross-disciplinary physics and related areas of science and technology)

  7. Isoindigo-based polymer field-effect transistors: effects of selenophene-substitution on high charge carrier mobility.

    Science.gov (United States)

    Park, Kwang Hun; Cheon, Kwang Hee; Lee, Yun-Ji; Chung, Dae Sung; Kwon, Soon-Ki; Kim, Yun-Hi

    2015-05-11

    We show that selenophene-substitution can be an efficient synthetic strategy toward high charge carrier mobility of isoindigo (IID)-based copolymers when their side chains are optimized. A high mobility of 5.8 cm(2) V(-1) s(-1) is demonstrated by a strategically designed IID-based polymer, with both side-chain adjustment and selenophene-substitution. PMID:25871952

  8. The Influence of Oxide Charge on Carrier Mobility in HfO2/TiN Gate Silicon MOSFETs

    NARCIS (Netherlands)

    Hurley, Paul K.; Negara, Adi; Hemert, van Tom; Cherkaoui, Karim

    2009-01-01

    In this work we will provide the results of an investigation into electron and hole mobility at high inversion charge density (6 to 8x1012 cm-2) in TiN/HfO2/SiOx/Si MOSFETs. We examine the influence of oxide charge on carrier mobility by using temperature bias stress to deliberately increase the den

  9. Inter-chain charge carrier mobility in conjugated polymers doped with polar additives

    Czech Academy of Sciences Publication Activity Database

    Toman, Petr

    Prague : CESNET, 2010 - (Křenková, I.; Antoš, D.; Matyska, L.), s. 137-143 ISBN 978-80-904173-7-3 R&D Projects: GA ČR GA203/06/0285; GA AV ČR IAA401770601; GA MŠk MEB050815 Institutional research plan: CEZ:AV0Z40500505 Keywords : charge carrier mobility * switching * Marcus theory Subject RIV: CF - Physical ; Theoretical Chemistry https://www.metacentrum.cz/export/ sites /metacentrum/cs/about/results/yearbooks/MetaCentrum_Yearbook9_web.pdf

  10. A new approach to calculate charge carrier transport mobility in organic molecular crystals from imaginary time path integral simulations

    Energy Technology Data Exchange (ETDEWEB)

    Song, Linze; Shi, Qiang, E-mail: qshi@iccas.ac.cn [Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Institute of Chemistry, Chinese Academy of Sciences, Zhongguancun, Beijing 100190 (China)

    2015-05-07

    We present a new non-perturbative method to calculate the charge carrier mobility using the imaginary time path integral approach, which is based on the Kubo formula for the conductivity, and a saddle point approximation to perform the analytic continuation. The new method is first tested using a benchmark calculation from the numerical exact hierarchical equations of motion method. Imaginary time path integral Monte Carlo simulations are then performed to explore the temperature dependence of charge carrier delocalization and mobility in organic molecular crystals (OMCs) within the Holstein and Holstein-Peierls models. The effects of nonlocal electron-phonon interaction on mobility in different charge transport regimes are also investigated.

  11. AN EFFICIENT QoS-CONSTRAINED RESOURCE ALLOCATION STRATEGY FOR MULTI-CARRIER MOBILE COMMUNICATION SYSTEMS

    Directory of Open Access Journals (Sweden)

    Srinivas Karedla

    2016-03-01

    Full Text Available Resource allocation strategies in Mobile Communication Systems (4G/5G are proposed to enhance the data transmission and to meet the required QoS of the users by reducing the interference (inter/intra cell. The aim of this paper is to propose an efficient QoS-Constrained resource allocation strategy called QoS-Constrained Modified Load Matrix (QoS-MLM for Multi -Carrier Mobile Communication systems under 4G LTE scenario to reduce interference and to improve aggregate throughput, packet delay. Simulation results show that by using QoS-MLM the aggregate throughput and packet delay has improved significantly when compared to benchmark schedulers.

  12. Measuring the mobility of single crystalline wires and its dependence on temperature and carrier density

    Energy Technology Data Exchange (ETDEWEB)

    Amorim, Cleber A; Berengue, Olivia M; Kamimura, Hanay; Chiquito, Adenilson J [NanO LaB-Departamento de Fisica, Universidade Federal de Sao Carlos, CEP 13565-905, CP 676, Sao Carlos, Sao Paulo (Brazil); Leite, Edson R, E-mail: amorim@df.ufscar.br [Laboratorio Interdisciplinar de EletroquImica e Ceramicas, Departamento de Quimica, Universidade Federal de Sao Carlos, CEP 13565-905, CP 676, Sao Carlos, Sao Paulo (Brazil)

    2011-05-25

    Kinetic transport parameters are fundamental for the development of electronic nanodevices. We present new results for the temperature dependence of mobility and carrier density in single crystalline In{sub 2}O{sub 3} samples and the method of extraction of these parameters which can be extended to similar systems. The data were obtained using a conventional Hall geometry and were quantitatively described by the semiconductor transport theory characterizing the electron transport as being controlled by the variable range hopping mechanism. A comprehensive analysis is provided showing the contribution of ionized impurities (low temperatures) and acoustic phonon (high temperatures) scattering mechanisms to the electron mobility. The approach presented here avoids common errors in kinetic parameter extraction from field effect data, serving as a versatile platform for direct investigation of any nanoscale electronic materials.

  13. High carrier mobility in chemically modified graphene on an atomically flat high-resistive substrate

    International Nuclear Information System (INIS)

    Special high-resistive substrates for graphene sheets are suggested with the aim of providing high conductivity and mobility of charge carriers in graphene. The substrates were created from N-methylpyrrolidone-intercalated few-layer graphene (FLG) using anneals given to FLG samples in the temperature range 100–180 °C. Structures containing a highly conductive single-layer graphene on an atomically flat, high-resistive substrate were produced by recovering the top-layer conductivity. The obtained structures have potential in electronic applications due to a high carrier mobility (up to 16 000–42 000 cm2 V−1 s−1) and strong gate-voltage-induced modulation (by 4–5 orders of magnitude) of the current in the top graphene layer. The strong gate-voltage-induced modulation of the current clearly demonstrated that the top layer was chemically modified graphene. The possibility of governing the surface conductivity in the described structures offers a unique tool for two-dimensional nanodesign. (paper)

  14. First principles prediction of the electronic structure and carrier mobilities of biaxially strained molybdenum trioxide (MoO3)

    Science.gov (United States)

    Dandogbessi, Bruno S.; Akin-Ojo, Omololu

    2016-08-01

    The electronic band structures of unstrained and biaxially strained MoO3 were determined by first-principles density functional theory calculations. From the band structures, the effects of strain on the charge carrier mobilities were investigated. These mobilities were calculated based on deformation potential theory. First, we found that the electron effective masses of unstrained bulk pristine MoO3 are about three times smaller than the corresponding hole effective masses, and, second, the electron mobility is about ten times the hole mobility, making the compound an electron transport material. Our results also show that, when compressed biaxially, as the strain increases from 0% to 1.5%, the electron (hole) mobility increases by 0% to 53% (0% to 17%). On the other hand, the application of a biaxial tensile strain decreases the electron (hole) mobility by 65% to 0% (90% to 0%), as the tensile strain increases from 0% to 1.5 % . These changes are caused mainly by the fact that the carrier effective masses reduce (increase) upon application of compressive (tensile) strain. Only the acoustic-phonon limited carrier mobilities were computed; hence, the actual mobilities cannot be less than the values obtained in this work.

  15. Emergence of high mobility hole-like carrier in Ba(Fe1-xMnxAs)2

    Science.gov (United States)

    Tanabe, Yoichi; Urata, Takahiro; Huynh, Khuong; Heguri, Satoshi; Oguro, Hidetoshi; Watanabe, Kazuo; Tanigaki, Katsumi

    2014-03-01

    An evolution of electronic states through impurity substitutions is one of key issues for understanding the electronic ground state of iron pnictides. In this talk, we will report the emergence of the hole-like carrier with high mobility in Ba(Fe1-xMnxAs)2. A clear sign change of the Hall resistivity at low magnetic fields indicated that the electron-like high mobility carrier changes to the hole-like one through Mn substitution, although the nuclear magnetic resonance revealed that the Mn substitution does not introduce any carrier doping. The evolution of p-type carrier will be discussed based on results of conductive tensor analyses. The research was partially supported by Grant-in-Aid for Young Scientists (B) (23740251) and GCOE program of Tohoku University.

  16. Mobile Carrier Selection In A Post-Conflict Environment – The Primacy Of Ethnicity Over Conventional Network Effects

    Directory of Open Access Journals (Sweden)

    Zaimović Tarik

    2015-12-01

    Full Text Available In this paper we analyze determinants which affect the selection of mobile carriers in a post-conflict environment - Bosnia and Herzegovina. We apply relevant probability modelling to test perceptions of individual respondents on different network effects obtained through a targeted representative survey. Furthermore, we explore whether some non-traditional influences might affect costumers, focusing on the role of demographic characteristics. Our results confirm that conventional network effects have a role in carrier selection, although they are different across carriers. However, we identify that the ethnicity of respondents overwhelms the traditional network effects by having the highest magnitude in the model. Our findings show that the “ethnic affiliation” of mobile carriers, attributed by the users, remains a persistent factor in attracting and keeping telecommunication costumers in Bosnia and Herzegovina.

  17. Intrinsic carrier mobility of a single-layer graphene covalently bonded with single-walled carbon nanotubes

    International Nuclear Information System (INIS)

    We report intrinsic carrier mobility calculations of a two-dimensional nanostructure that consists of porous single layer graphene covalently bonded with single-walled carbon nanotubes on both sides. We used first-principles calculation and found that the deformation potential of such system is about 25% of that of graphene, and the carrier mobility is about 5 × 104 cm2 V−1 s−1 for both electrons and holes, about one order of magnitude lower than that of graphene. This nanostructure and its three-dimensional stacking could serve as novel organic electronic materials.

  18. Thermoelectric and micro-Raman measurements of carrier density and mobility in heavily Si-doped GaN wires

    OpenAIRE

    Tchoulfian, Pierre; Donatini, Fabrice; Levy, François; Amstatt, Benoît; Dussaigne, Amélie; Ferret, Pierre; Bustarret, Etienne; Pernot, Julien

    2013-01-01

    Combined thermoelectric-resistivity measurements and micro-Raman experiments have been performed on single heavily Si-doped GaN wires. In both approaches, similar carrier concentration and mobility were determined taking into account the non-parabolicity of the conduction band. The unique high conductivity of Si-doped GaN wires is explained by a mobility µ=56 cm2 /V s at a carrier concentration n = 2.6 10^20 /cm 3. This is attributed to a more efficient dopant incorporation in Si-doped GaN mi...

  19. Side chain engineering of fused aromatic thienopyrazine based low band-gap polymers for enhanced charge carrier mobility

    KAUST Repository

    Mondal, Rajib

    2011-01-01

    A strategic side-chain engineering approach leads to the two orders of magnitude enhancement of charge carrier mobility in phenanthrene based fused aromatic thienopyrazine polymers. Hole carrier mobility up to 0.012 cm 2/Vs can be obtained in thin film transistor devices. Polymers were also utilized to fabricate bulk heterojunction photovoltaic devices and the maximum PCE obtained in these OPV\\'s was 1.15%. Most importantly, performances of the devices were correlated with thin morphological analysis performed by atomic force microscopy and grazing incidence X-ray scattering. © 2011 The Royal Society of Chemistry.

  20. Influence of tellurium content and chlorine concentration on carrier drift mobility of Se100-xTex:Cl glasses

    International Nuclear Information System (INIS)

    Carrier drift mobility in undoped and doped with chlorine Se100-xTex (0≤x≤10) glassy alloys has been investigated as a function of Te content and Cl concentration. It was found that the drift mobilities of both electrons and holes were decreased with Te content increasing. The dependence of the carriers drift mobilities on Cl concentration followed a complicated behavior and was resulted in rapid decrease of the hole mobility when chlorine concentration approached 0.1 at.%. The concentrations and energies of localized states controlling the charge transport in the material have been found depending on Te content and Cl concentration. The observed charge-transport features are considered to attribute to changes in the concentrations of intrinsic charged defects and explained in terms of VAP model. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  1. Improved carrier mobility of chemical vapor deposition-graphene by counter-doping with hydrazine hydrate

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Zhiying; Zhang, Yanhui; Zhang, Haoran; Sui, Yanping; Zhang, Yaqian; Ge, Xiaoming; Yu, Guanghui, E-mail: ghyu@mail.sim.ac.cn; Xie, Xiaoming; Li, Xiaoliang [State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050 (China); Jin, Zhi; Liu, Xinyu [Microwave Devices and Integrated Circuits Department, Institute of Microelectronics, Chinese Academy of Sciences, Beijing 100029 (China)

    2015-03-02

    We developed a counter-doping method to tune the electronic properties of chemical vapor deposition (CVD)-grown graphene by varying the concentration and time of graphene exposure to hydrazine hydrate (N{sub 2}H{sub 4}·H{sub 2}O). The shift of G and 2D peaks of Raman spectroscopy is analyzed as a function of N{sub 2}H{sub 4}·H{sub 2}O concentration. The result revealed that N{sub 2}H{sub 4}·H{sub 2}O realized n-type doping on CVD grown graphene. X-ray photoelectron spectroscopy measurement proved the existence of nitrogen, which indicated the adsorption of N{sub 2}H{sub 4} on the surface of graphene. After counter-doping, carrier mobility, which was measured by Hall measurements, increased three fold.

  2. Improved carrier mobility of chemical vapor deposition-graphene by counter-doping with hydrazine hydrate

    International Nuclear Information System (INIS)

    We developed a counter-doping method to tune the electronic properties of chemical vapor deposition (CVD)-grown graphene by varying the concentration and time of graphene exposure to hydrazine hydrate (N2H4·H2O). The shift of G and 2D peaks of Raman spectroscopy is analyzed as a function of N2H4·H2O concentration. The result revealed that N2H4·H2O realized n-type doping on CVD grown graphene. X-ray photoelectron spectroscopy measurement proved the existence of nitrogen, which indicated the adsorption of N2H4 on the surface of graphene. After counter-doping, carrier mobility, which was measured by Hall measurements, increased three fold

  3. Evidence of low-mobile charge carriers in YBa2Cu3O6+x

    International Nuclear Information System (INIS)

    The present work results reveal that the heterogeneous system is one of the forms of oxygen nonstoichiometry, realization of oxygen-deficient YBa2Cu3O6+x. It is noteworthy that NMP is formed above 980 C through labile oxygen redistribution and leaves the lattice of heavy ions invariable. Being a random microscopically inhomogeneous media the NW exhibits a number of anomalous dielectric properties absent for each separate component. Probably the degree of labile oxygen segregation in NMP is so high, that static permittivity of dielectric phase is completely determined by small polarons. On the other hand the NMP DF measurements provide an effective values of mobility and its activation energy giving a rough idea of small polarons dynamics. At low temperature the picture is complicated by nonequilibrium charge carriers excitation. To elaborate an adequate model of the entire phenomenon, more detailed information on oxygen positions and phase percolation threshold is necessary

  4. Improved carrier mobility of chemical vapor deposition-graphene by counter-doping with hydrazine hydrate

    Science.gov (United States)

    Chen, Zhiying; Zhang, Yanhui; Zhang, Haoran; Sui, Yanping; Zhang, Yaqian; Ge, Xiaoming; Yu, Guanghui; Xie, Xiaoming; Li, Xiaoliang; Jin, Zhi; Liu, Xinyu

    2015-03-01

    We developed a counter-doping method to tune the electronic properties of chemical vapor deposition (CVD)-grown graphene by varying the concentration and time of graphene exposure to hydrazine hydrate (N2H4.H2O). The shift of G and 2D peaks of Raman spectroscopy is analyzed as a function of N2H4.H2O concentration. The result revealed that N2H4.H2O realized n-type doping on CVD grown graphene. X-ray photoelectron spectroscopy measurement proved the existence of nitrogen, which indicated the adsorption of N2H4 on the surface of graphene. After counter-doping, carrier mobility, which was measured by Hall measurements, increased three fold.

  5. Charge carrier mobilities in organic semiconductors: crystal engineering and the importance of molecular contacts.

    Science.gov (United States)

    Bashir, Asif; Heck, Alexander; Narita, Akimitsu; Feng, Xinliang; Nefedov, Alexei; Rohwerder, Michael; Müllen, Klaus; Elstner, Marcus; Wöll, Christof

    2015-09-14

    We have conducted a combined experimental and theoretical study on the optimization of hexa-peri-hexabenzocoronene (HBC) as organic semiconductor. While orientations with high electronic coupling are unfavorable in the native liquid crystalline phase of HBC, we enforced such orientations by applying external constraints. To this end, self-assembled monolayers (SAMs) were formed by a non-conventional preparation method on an Au-substrate using electrochemical control. Within these SAMs the HBC units are forced into favorable orientations that cannot be achieved by unconstrained crystallization. For simulating the charge transport we applied a recently developed approach, where the molecular structure and the charge carrier are propagated simultaneously during a molecular dynamics simulation. Experiments as well as simulations are mutually supportive of an improved mobility in these novel materials. The implication of these findings for a rational design of future organic semiconductors will be discussed. PMID:26235109

  6. Study of high mobility carriers in Ni-doped CdO films

    Indian Academy of Sciences (India)

    A A Dakhel

    2013-10-01

    Cadmium oxide (CdO) doped with different amounts of nickel ion thin films have been prepared on silicon and glass substrates by vacuum evaporation technique. The effects of nickel doping on the structural, electrical, optical and optoelectronic properties of the host CdO films were systematically studied. The sample elemental composition was determined by the X-ray fluorescence spectroscopy method. The X-ray diffraction method was used to study the crystalline structure of the samples. It shows that some of Ni3+ ions occupy mainly locations when in interstitial positions and Cd2+-ion vacancies of CdO lattice. The bandgap of Ni-doped CdO suffers narrowing till 10–12% compared to undoped CdO. Such bandgap narrowing was studied within the framework of the available models. The electrical behaviours show that all the prepared Ni-doped CdO films are degenerate semiconductors. However, the nickel doping influences all the optoelectrical properties of CdO. Their d.c. conductivity, carrier concentration and mobility increased compared to undoped CdO film. The largest mobility of 112.6 cm2/V.s was measured for 1–2% Ni-doped CdO film. From optoelectronics point of view, Ni-doped CdO can be used in infrared-transparent-conducting-oxide (NIR–TCO) applications.

  7. Al2C Monolayer Sheet and Nanoribbons with Unique Direction-Dependent Acoustic-Phonon-Limited Carrier Mobility and Carrier Polarity.

    Science.gov (United States)

    Xu, Yuehua; Dai, Jun; Zeng, Xiao Cheng

    2016-01-21

    The intrinsic acoustic-phonon-limited carrier mobility (μ) of Al2C monolayer sheet and nanoribbons are investigated using ab initio computation and deformation potential theory. It is found that the polarity of the room-temperature carrier mobility of the Al2C monolayer is direction-dependent, with μ of electron (e) and hole (h) being 2348 and 40.77 cm(2)/V/s, respectively, in the armchair direction and 59.95 (e) and 705.8 (h) in the zigzag direction. More interestingly, one-dimensional Al2C nanoribbons not only can retain the direction-dependent polarity but also may entail even higher mobility, in contrast to either the graphene nanoribbons which tend to exhibit lower μ compared to the two-dimensional graphene or the MoS2 nanoribbons which have reversed polarity compared to the MoS2 sheet. As an example, the Al-terminated zigzag nanoribbon with a width of 4.1 nm exhibits μ of 212.6 (e) and 2087 (h) cm(2)/V/s, while the C-terminated armchair nanoribbon with a width 2.6 nm exhibits μ of 1090 (e) and 673.9 (h) cm(2)/V/s; the C-terminated zigzag nanoribbon with a width 3.7 nm exhibits μ of 177.6 (e) and 1889 (h) cm(2)/V/s, and the Al-terminated armchair nanoribbon with a width 2.4 nm exhibits μ of 6695 (e) and 518.4 (h) cm(2)/V/s. The high carrier mobility, μ, coupled with polarity and direction dependence endows the Al2C sheet and nanoribbons with unique transport properties that can be exploited for special applications in nanoelectronics. PMID:26722716

  8. Electron-phonon coupling modification and carrier mobility enhancement in poly(3,4-ethylenedioxythiophene) doped with poly(4-styrenesulfonate) films by ultraviolet irradiation

    International Nuclear Information System (INIS)

    The effect of ultraviolet irradiation on the electrical property of poly(3,4-ethylenedioxythiophene) doped with poly(4-styrenesulfonate) (PEDOT:PSS) films was examined. It is shown that the carrier mobility increases while the carrier density does not change substantially. The carrier mobility in PEDOT:PSS samples exhibits strong temperature dependence, indicating the dominance of tunneling (hopping) at low (high) temperatures. The results demonstrate that changes in the chemical structure may lead to the modification of the electron-phonon coupling, thus increasing the carrier mobility in PEDOT:PSS

  9. Limits of carrier mobility in Sb-doped SnO{sub 2} conducting films deposited by reactive sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Bissig, B., E-mail: Benjamin.bissig@empa.ch; Jäger, T.; Tiwari, A. N.; Romanyuk, Y. E. [Laboratory for Thin Films and Photovoltaics, Empa, Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, 8600 Dübendorf (Switzerland); Ding, L. [Photovoltaics and Thin Film Electronics Laboratory, Ecole Polytechnique Fédérale Lausanne (EPFL), Institute of Microengineering (IMT), Rue de la Maladière 71b, 2002 Neuchâtel (Switzerland)

    2015-06-01

    Electron transport in Sb-doped SnO{sub 2} (ATO) films is studied to unveil the limited carrier mobility observed in sputtered films as compared to other deposition methods. Transparent and conductive ATO layers are deposited from metallic tin targets alloyed with antimony in oxygen atmosphere optimized for reactive sputtering. The carrier mobility decreases from 24 cm{sup 2} V{sup −1} s{sup −1} to 6 cm{sup 2} V{sup −1} s{sup −1} when increasing the doping level from 0 to 7 at. %, and the lowest resistivity of 1.8 × 10{sup −3} Ω cm corresponding to the mobility of 12 cm{sup 2} V{sup −1} s{sup −1} which is obtained for the 3 at. % Sb-doped ATO. Temperature-dependent Hall effect measurements and near-infrared reflectance measurements reveal that the carrier mobility in sputtered ATO is limited by ingrain scattering. In contrast, the mobility of unintentionally doped SnO{sub 2} films is determined mostly by the grain boundary scattering. Both limitations should arise from the sputtering process itself, which suffers from the high-energy-ion bombardment and yields polycrystalline films with small grain size.

  10. Limits of carrier mobility in Sb-doped SnO2 conducting films deposited by reactive sputtering

    Directory of Open Access Journals (Sweden)

    B. Bissig

    2015-06-01

    Full Text Available Electron transport in Sb-doped SnO2 (ATO films is studied to unveil the limited carrier mobility observed in sputtered films as compared to other deposition methods. Transparent and conductive ATO layers are deposited from metallic tin targets alloyed with antimony in oxygen atmosphere optimized for reactive sputtering. The carrier mobility decreases from 24 cm2 V−1 s−1 to 6 cm2 V−1 s−1 when increasing the doping level from 0 to 7 at. %, and the lowest resistivity of 1.8 × 10−3 Ω cm corresponding to the mobility of 12 cm2 V−1 s−1 which is obtained for the 3 at. % Sb-doped ATO. Temperature-dependent Hall effect measurements and near-infrared reflectance measurements reveal that the carrier mobility in sputtered ATO is limited by ingrain scattering. In contrast, the mobility of unintentionally doped SnO2 films is determined mostly by the grain boundary scattering. Both limitations should arise from the sputtering process itself, which suffers from the high-energy-ion bombardment and yields polycrystalline films with small grain size.

  11. A new approach to calculate charge carrier transport mobility in organic molecular crystals from imaginary time path integral simulations.

    Science.gov (United States)

    Song, Linze; Shi, Qiang

    2015-05-01

    We present a new non-perturbative method to calculate the charge carrier mobility using the imaginary time path integral approach, which is based on the Kubo formula for the conductivity, and a saddle point approximation to perform the analytic continuation. The new method is first tested using a benchmark calculation from the numerical exact hierarchical equations of motion method. Imaginary time path integral Monte Carlo simulations are then performed to explore the temperature dependence of charge carrier delocalization and mobility in organic molecular crystals (OMCs) within the Holstein and Holstein-Peierls models. The effects of nonlocal electron-phonon interaction on mobility in different charge transport regimes are also investigated. PMID:25956086

  12. Pressure-Modulated Conductivity, Carrier Density, and Mobility of Multilayered Tungsten Disulfide.

    Science.gov (United States)

    Nayak, Avinash P; Yuan, Zhen; Cao, Boxiao; Liu, Jin; Wu, Junjie; Moran, Samuel T; Li, Tianshu; Akinwande, Deji; Jin, Changqing; Lin, Jung-Fu

    2015-09-22

    Tungsten disulfide (WS2) is a layered transition metal dichalcogenide (TMD) that differs from other two-dimensional (2D) compounds such as graphene due to its unique semiconducting, tunable-band-gap nature. Multilayered WS2 exhibits an indirect band gap Eg of ∼1.3 eV, along with a higher load-bearing ability that is promising for strain-tuning device applications, but the electronic properties of multilayered WS2 at higher strain conditions (i.e., static strain >12%) remain an open question. Here we have studied the structural, electronic, electrical, and vibrational properties of multilayered WS2 at hydrostatic pressures up to ∼35 GPa experimentally in a diamond anvil cell and theoretically using first-principles ab initio calculations. Our results show that WS2 undergoes an isostructural semiconductor-to-metallic (S-M) transition at approximately 22 GPa at 280 K, which arises from the overlap of the highest valence and lowest conduction bands. The S-M transition is caused by increased sulfur-sulfur interactions as the interlayer spacing decreases with applied hydrostatic pressure. The metalization in WS2 can be alternatively interpreted as a 2D to 3D (three-dimensional) phase transition that is associated with a substantial modulation of the charge carrier characteristics including a 6-order decrease in resistivity, a 2-order decrease in mobility, and a 4-order increase in carrier concentration. These distinct pressure-tunable characteristics of the dimensionalized WS2 differentiate it from other TMD compounds such as MoS2 and promise future developments in strain-modulated advanced devices. PMID:26258661

  13. Tunable Band Alignment with Unperturbed Carrier Mobility of On-Surface Synthesized Organic Semiconducting Wires.

    Science.gov (United States)

    Basagni, Andrea; Vasseur, Guillaume; Pignedoli, Carlo A; Vilas-Varela, Manuel; Peña, Diego; Nicolas, Louis; Vitali, Lucia; Lobo-Checa, Jorge; de Oteyza, Dimas G; Sedona, Francesco; Casarin, Maurizio; Ortega, J Enrique; Sambi, Mauro

    2016-02-23

    The tunable properties of molecular materials place them among the favorites for a variety of future generation devices. In addition, to maintain the current trend of miniaturization of those devices, a departure from the present top-down production methods may soon be required and self-assembly appears among the most promising alternatives. On-surface synthesis unites the promises of molecular materials and of self-assembly, with the sturdiness of covalently bonded structures: an ideal scenario for future applications. Following this idea, we report the synthesis of functional extended nanowires by self-assembly. In particular, the products correspond to one-dimensional organic semiconductors. The uniaxial alignment provided by our substrate templates allows us to access with exquisite detail their electronic properties, including the full valence band dispersion, by combining local probes with spatial averaging techniques. We show how, by selectively doping the molecular precursors, the product's energy level alignment can be tuned without compromising the charge carrier's mobility. PMID:26841052

  14. Polarity-reversed robust carrier mobility in monolayer MoS₂ nanoribbons.

    Science.gov (United States)

    Cai, Yongqing; Zhang, Gang; Zhang, Yong-Wei

    2014-04-30

    Using first-principles calculations and deformation potential theory, we investigate the intrinsic carrier mobility (μ) of monolayer MoS2 sheet and nanoribbons. In contrast to the dramatic deterioration of μ in graphene upon forming nanoribbons, the magnitude of μ in armchair MoS2 nanoribbons is comparable to its sheet counterpart, albeit oscillating with ribbon width. Surprisingly, a room-temperature transport polarity reversal is observed with μ of hole (h) and electron (e) being 200.52 (h) and 72.16 (e) cm(2) V(-1) s(-1) in sheet, and 49.72 (h) and 190.89 (e) cm(2) V(-1) s(-1) in 4 nm nanoribbon. The high and robust μ and its polarity reversal are attributable to the different characteristics of edge states inherent in MoS2 nanoribbons. Our study suggests that width reduction together with edge engineering provide a promising route for improving the transport properties of MoS2 nanostructures. PMID:24712770

  15. Two-frequency method for measuring Hall emf in high-resistive materials with charge-carrier low mobility

    International Nuclear Information System (INIS)

    A facility for measuring Hall emf in high-resistive materials with low mobility of charge carriers by the two-frequency method using digital synchronous integration is described. The facility permits to detect the minimum Hall emf approxamatety equat to 5 μV at approximatety equal to 1 T Ohm of the investigated.sample resistance during the measuring time of approximately equal to 2000 s. Sensitivity by Hall mobility makes up >= 0.01 cm2/Vxs at the same measuring time. Measuring results of the Hall emf on GaAs monocrystals, CdSe films and island film of gold are presented

  16. High carrier mobility of CoPc wires based field-effect transistors using bi-layer gate dielectric

    Directory of Open Access Journals (Sweden)

    Murali Gedda

    2013-11-01

    Full Text Available Polyvinyl alcohol (PVA and anodized Al2O3 layers were used as bi-layer gate for the fabrication of cobalt phthalocyanine (CoPc wire base field-effect transistors (OFETs. CoPc wires were grown on SiO2 surfaces by organic vapor phase deposition method. These devices exhibit a field-effect carrier mobility (μEF value of 1.11 cm2/Vs. The high carrier mobility for CoPc molecules is attributed to the better capacitive coupling between the channel of CoPc wires and the gate through organic-inorganic dielectric layer. Our measurements also demonstrated the way to determine the thicknesses of the dielectric layers for a better process condition of OFETs.

  17. High carrier mobility of CoPc wires based field-effect transistors using bi-layer gate dielectric

    International Nuclear Information System (INIS)

    Polyvinyl alcohol (PVA) and anodized Al2O3 layers were used as bi-layer gate for the fabrication of cobalt phthalocyanine (CoPc) wire base field-effect transistors (OFETs). CoPc wires were grown on SiO2 surfaces by organic vapor phase deposition method. These devices exhibit a field-effect carrier mobility (μEF) value of 1.11 cm2/Vs. The high carrier mobility for CoPc molecules is attributed to the better capacitive coupling between the channel of CoPc wires and the gate through organic-inorganic dielectric layer. Our measurements also demonstrated the way to determine the thicknesses of the dielectric layers for a better process condition of OFETs

  18. High carrier mobility of CoPc wires based field-effect transistors using bi-layer gate dielectric

    Energy Technology Data Exchange (ETDEWEB)

    Gedda, Murali; Obaidulla, Sk. Md. [Department of Physics, Indian Institute of Technology Guwahati, Guwahati-781039 (India); Subbarao, Nimmakayala V. V. [Centre for Nano Technology, Indian Institute of Technology Guwahati, Guwahati-781039 (India); Goswami, Dipak K. [Department of Physics, Indian Institute of Technology Guwahati, Guwahati-781039 (India); Centre for Nano Technology, Indian Institute of Technology Guwahati, Guwahati-781039 (India)

    2013-11-15

    Polyvinyl alcohol (PVA) and anodized Al{sub 2}O{sub 3} layers were used as bi-layer gate for the fabrication of cobalt phthalocyanine (CoPc) wire base field-effect transistors (OFETs). CoPc wires were grown on SiO{sub 2} surfaces by organic vapor phase deposition method. These devices exhibit a field-effect carrier mobility (μ{sub EF}) value of 1.11 cm{sup 2}/Vs. The high carrier mobility for CoPc molecules is attributed to the better capacitive coupling between the channel of CoPc wires and the gate through organic-inorganic dielectric layer. Our measurements also demonstrated the way to determine the thicknesses of the dielectric layers for a better process condition of OFETs.

  19. Growth Related Carrier Mobility Enhancement of Pentacene Thin-Film Transistors with High-k Oxide Gate Dielectric

    Institute of Scientific and Technical Information of China (English)

    YU Ai-Fang; QI Qiong; JIANG Peng; JIANG Chao

    2009-01-01

    Carrier mobifity enhancement from 0.09 to 0.59cm2/Vs is achieved for pentacene-based thin-film transistors (TFTs) by modifying the HfO2 gate dielectric with a polystyrene (PS) thin film. The improvement of the transistor's performance is found to be strongly related to the initial film morphologies of pentacene on the dielectrics. In contrast to the three-dimensional island-like growth mode on the HfO2 surface, the Stranski-Krastanov growth mode on the smooth and nonpolar PS/HfO2 surface is believed to be the origin of the excellent carrier mobifity of the TFTs. A large well-connected first monolayer with fewer boundaries is formed via the Stranski-Krastanov growth mode, which facilitates a charge transport parallel to the substrate and promotes higher carrier mobility.

  20. Improvement in carrier mobility and photovoltaic performance through random distribution of segments of linear and branched side chains

    Czech Academy of Sciences Publication Activity Database

    Egbe, D. A. M.; Adam, G.; Pivrikas, A.; Ramil, A. M.; Birckner, E.; Cimrová, Věra; Hoppe, H.; Sariciftci, N. S.

    2010-01-01

    Roč. 20, č. 43 (2010), s. 9726-9734. ISSN 0959-9428 R&D Projects: GA MŠk(CZ) 1M06031 Institutional research plan: CEZ:AV0Z40500505 Keywords : poly(p-phenylene-ethynylene)-alt-poly(p-phenylene-vinylene) * solar cells * charge carrier mobility Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 5.101, year: 2010

  1. Performance Evaluation of LTE−Advanced Downlink in Inter and Intra Band Carrier Aggregation Under Mobility and Interference

    OpenAIRE

    Almesaeed, Reham N F; Ameen, Araz S; Doufexi, Angela; Nix, Andrew R

    2014-01-01

    LTE−Advanced is a promising technology for a higher spectral efficiency and reliable transmission. This paper compares the downlink throughput experienced by mobile users in a macro-cell in an interference limited scenario with a frequency reuse of one. Bit accurate link level simulations are performed for the downlink physical shared channel (PDSCH). The study is performed for a single antenna system in specific routes at two different carrier frequencies (800 MHz and 2.6 GHz), for two urban...

  2. How High Local Charge Carrier Mobility and an Energy Cascade in a Three-Phase Bulk Heterojunction Enable >90% Quantum Efficiency

    KAUST Repository

    Burke, Timothy M.

    2013-12-27

    Charge generation in champion organic solar cells is highly efficient in spite of low bulk charge-carrier mobilities and short geminate-pair lifetimes. In this work, kinetic Monte Carlo simulations are used to understand efficient charge generation in terms of experimentally measured high local charge-carrier mobilities and energy cascades due to molecular mixing. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Diffusivity and mobility of non-equilibrium carriers in organic semiconductors: Existence of critical field determining temperature dependence

    Science.gov (United States)

    Tripathi, Durgesh C.; Sinha, Dhirendra K.; Mohapatra, Y. N.

    2013-10-01

    The role of disorder in controlling diffusivity and mobility of charge-carriers in the hopping regime of transport within a potential landscape has become especially significant for organic semiconductors. The temperature and field dependence of diffusivity (D) and mobility (μ) of injected charge-carriers have been simultaneously measured using electroluminescence transients for representative organic thin-films of tris(8-hydroxyquinoline) aluminum (III) (Alq3) and poly(9,9-dioctylfluorenyl-2,7-diyl) (PFO). Significantly, the field dependence of diffusivity at different temperatures is similar except for a shift of a critical field beyond which it shows a sharp increase. The critical field is shown to be linearly decreasing with temperature ultimately vanishing at a characteristic limit T∗, and the slope is a measure of the localization length. The normalization of diffusivity is used to demonstrate the role of field in controlling temperature dependence. The scheme has been used to neatly decouple contributions from energetic (diagonal) and positional (off-diagonal) disorder thus enabling independent experimental determination of all the parameters of standard and correlated versions of Gaussian disorder model. The results demonstrate the validity of Gaussian disorder model even for non-equilibrium carriers, and that the parameters can be obtained with appropriate scaling of the field in such cases.

  4. Investigations of the drift mobility of carriers and density of states in nanocrystalline CdS thin films

    Science.gov (United States)

    Singh, Baljinder; Singh, Janpreet; Kaur, Jagdish; Moudgil, R. K.; Tripathi, S. K.

    2016-06-01

    Nanocrystalline Cadmium Sulfide (nc-CdS) thin films have been prepared on well-cleaned glass substrate at room temperature (300 K) by thermal evaporation technique using inert gas condensation (IGC) method. X-ray diffraction (XRD) analysis reveals that the films crystallize in hexagonal structure with preferred orientation along [002] direction. Scanning electron microscope (SEM) and Transmission electron microscope (TEM) studies reveal that grains are spherical in shape and uniformly distributed over the glass substrates. The optical band gap of the film is estimated from the transmittance spectra. Electrical parameters such as Hall coefficient, carrier type, carrier concentration, resistivity and mobility are determined using Hall measurements at 300 K. Transit time and mobility are estimated from Time of Flight (TOF) transient photocurrent technique in gap cell configuration. The measured values of electron drift mobility from TOF and Hall measurements are of the same order. Constant Photocurrent Method in ac-mode (ac-CPM) is used to measure the absorption spectra in low absorption region. By applying derivative method, we have converted the measured absorption data into a density of states (DOS) distribution in the lower part of the energy gap. The value of Urbach energy, steepness parameter and density of defect states have been calculated from the absorption and DOS spectra.

  5. Charge carrier mobility in poly[methyl(phenyl)silylene] studied by time-resolved terahertz spectroscopy and molecular modeling

    Czech Academy of Sciences Publication Activity Database

    Němec, Hynek; Kratochvílová, Irena; Kužel, Petr; Šebera, Jakub; Kochalska, Anna; Nožár, Juraj; Nešpůrek, Stanislav

    2011-01-01

    Roč. 13, č. 7 (2011), s. 2850-2856. ISSN 1463-9076 R&D Projects: GA ČR(CZ) GP202/09/P099; GA ČR GA203/08/1594; GA AV ČR KAN401770651; GA MŠk LC512; GA ČR(CZ) GAP304/10/1951 Institutional research plan: CEZ:AV0Z10100520; CEZ:AV0Z40500505 Keywords : molecular electronics * THz spectroscopy * charge carrier mobility Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.573, year: 2011

  6. Impact of Gate Dielectric in Carrier Mobility in Low Temperature Chalcogenide Thin Film Transistors for Flexible Electronics

    KAUST Repository

    Salas-Villasenor, A. L.

    2010-06-29

    Cadmium sulfide thin film transistors were demonstrated as the n-type device for use in flexible electronics. CdS thin films were deposited by chemical bath deposition (70° C) on either 100 nm HfO2 or SiO2 as the gate dielectrics. Common gate transistors with channel lengths of 40-100 μm were fabricated with source and drain aluminum top contacts defined using a shadow mask process. No thermal annealing was performed throughout the device process. X-ray diffraction results clearly show the hexagonal crystalline phase of CdS. The electrical performance of HfO 2 /CdS -based thin film transistors shows a field effect mobility and threshold voltage of 25 cm2 V-1 s-1 and 2 V, respectively. Improvement in carrier mobility is associated with better nucleation and growth of CdS films deposited on HfO2. © 2010 The Electrochemical Society.

  7. Determination of energy band diagram and charge carrier mobility of white emitting polymer from optical, electrical and impedance spectroscopy

    International Nuclear Information System (INIS)

    A single-layer white polymer light-emitting device (WPLED) has been fabricated using spin coating technique. The device was constructed as ITO/PEDOT:PSS(50 nm)/SPW-111(50 nm)/LiF(1 nm)/Al(100 nm). Indium tin oxide (ITO) and poly(3,4-ethylenedioxythiophene) Polystyrene sulfonate (PEDOT:PSS) are used as the transparent anode. SPW-111 is fabricated as a white emissive layer and lithium fluoride (LiF) and aluminum (Al) are used as reflecting cathode. Energy band diagram of the device was estimated from a combination of ultraviolet–visible (UV–vis) and current–voltage (J–V) analyses. Charge carrier mobility (μ) of PLED was evaluated using negative differential susceptance (−ΔB) method from impedance spectroscopy (IS) analysis. The calculated μ of the SPW-111 device is in the magnitude of 10−6 cm2/V/s. - Highlights: • Single layer PLED has been fabricated with spin-coating technique and device performance has been evaluated. • Energy band diagram of the SPW-111 is estimated from optical and electrical analyses. • Charge carrier mobility of the SPW-111 materials is obtained by impedance spectroscopy

  8. Influence of heteroaggregation processes between intrinsic colloids and carrier colloids on cerium(III) mobility through fractured carbonate rocks.

    Science.gov (United States)

    Tran, Emily; Klein Ben-David, Ofra; Teutch, Nadya; Weisbrod, Noam

    2016-09-01

    Colloid facilitated transport of radionuclides has been implicated as a major transport vector for leaked nuclear waste in the subsurface. Sorption of radionuclides onto mobile carrier colloids such as bentonite and humic acid often accelerates their transport through saturated rock fractures. Here, we employ column studies to investigate the impact of intrinsic, bentonite and humic acid colloids on the transport and recovery of Ce(III) through a fractured chalk core. Ce(III) recovery where either bentonite or humic colloids were added was 7.7-26.9% Ce for all experiments. Greater Ce(III) recovery was observed when both types of carrier colloids were present (25.4-37.4%). When only bentonite colloids were present, Ce(III) appeared to be fractionated between chemical sorption to the bentonite colloid surfaces and heteroaggregation of bentonite colloids with intrinsic carbonate colloids, precipitated naturally in solution. However, scanning electron microscope (SEM) images and colloid stability experiments reveal that in suspensions of humic acid colloids, colloid-facilitated Ce(III) migration results only from the latter attachment mechanism rather than from chemical sorption. This observed heteroaggregation of different colloid types may be an important factor to consider when predicting potential mobility of leaked radionuclides from geological repositories for spent fuel located in carbonate rocks. PMID:27183207

  9. Charge-carrier mobilities in Cd(0.8)Zn(0.2)Te single crystals used as nuclear radiation detectors

    Science.gov (United States)

    Burshtein, Z.; Jayatirtha, H. N.; Burger, A.; Butler, J. F.; Apotovsky, B.; Doty, F. P.

    1993-01-01

    Charge-carrier mobilities were measured for the first time in Cd(0.8)Zn(0.2)Te single crystals using time-of-flight measurements of charge carriers produced by short (10 ns) light pulses from a frequency-doubled Nd:YAG laser (532 nm). The electron mobility displayed a T exp -1.1 dependence on the absolute temperature T in the range 200-320 K, with a room-temperature mobility of 1350 sq cm/V s. The hole mobility displayed a T exp -2.0 dependence in the same temperature range, with a room-temperature mobility of 120 sq cm/V s. Cd(0.8)Zn(0.2)Te appears to be a very favorable material for a room-temperature electronic nuclear radiation detector.

  10. Ionic Wind Phenomenon and Charge Carrier Mobility in Very High Density Argon Corona Discharge Plasma

    Science.gov (United States)

    Nur, M.; Bonifaci, N.; Denat, A.

    2014-04-01

    Wind ions phenomenon has been observed in the high density argon corona discharge plasma. Corona discharge plasma was produced by point to plane electrodes and high voltage DC. Light emission from the recombination process was observed visually. The light emission proper follow the electric field lines that occur between point and plane electrodes. By using saturation current, the mobilities of non-thermal electrons and ions have been obtained in argon gas and liquid with variation of density from 2,5 1021 to 2 1022 cm-3. In the case of ions, we found that the behaviour of the apparent mobility inversely proportional to the density or follow the Langevin variation law. For non-thermal electron, mobility decreases and approximately follows a variation of Langevin type until the density <= 0,25 the critical density of argon.

  11. Titanium trisulfide monolayer: theoretical prediction of a new direct-gap semiconductor with high and anisotropic carrier mobility.

    Science.gov (United States)

    Dai, Jun; Zeng, Xiao Cheng

    2015-06-22

    A new two-dimensional (2D) layered material, namely, titanium trisulfide (TiS3 ) monolayer, is predicted to possess novel electronic properties. Ab initio calculations show that the perfect TiS3 monolayer is a direct-gap semiconductor with a bandgap of 1.02 eV, close to that of bulk silicon, and with high carrier mobility. More remarkably, the in-plane electron mobility of the 2D TiS3 is highly anisotropic, amounting to about 10 000 cm(2)  V(-1)  s(-1) in the b direction, which is higher than that of the MoS2 monolayer, whereas the hole mobility is about two orders of magnitude lower. Furthermore, TiS3 possesses lower cleavage energy than graphite, suggesting easy exfoliation for TiS3 . Both dynamical and thermal stability of the TiS3 monolayer is examined by phonon-spectrum calculation and Born-Oppenheimer molecular dynamics simulation. The desired electronic properties render the TiS3 monolayer a promising 2D atomic-layer material for applications in future nanoelectronics. PMID:25966901

  12. Influence of solution concentration on orientation and related carrier mobility of P3HT thin film by synchrotron GIXRD

    International Nuclear Information System (INIS)

    Background: Molecule chain orientations of conjugated polymer have dramatic influence on corresponding device performance, which can be controlled by the methods such as varying the solvents with different boiling point. Purpose: We attempted to study the influence of solution concentration on orientation and related carrier mobility of P3HT thin film. Methods: The P3HT thin films were made by spin-coating from chloroform solution of different concentration and characterized using UV-Vis absorption spectra, grazing incidence X-ray diffraction. The organic thin film transistors were also fabricated to characterize the corresponding mobility . Results: The absorption peaks of the thin film prepared with low concentration solution red-shifted compared with that of high concentration. In out-of-plane GIXRD the relative intensity of (100) peak increased with decreasing concentration while the (010) peak moved in reverse. (100) diffraction dot in 2D GIXRD of thin film prepared with high concentration solution was mainly in out-of-plane direction while that with low concentration solution was mainly in in-plane direction. Conclusion: Based on the above results, the orientation changes from face-on orientation to edge-on orientation as the solution concentration decreases, which achieves the same effect with that of high boiling point solvents and enhances the mobility. It is possibly due to that low concentration solution needs more time to evaporate. (authors)

  13. Driving Sustainable Competitive Advantage in the Mobile Industry: Evidence from U.S. Wireless Carriers

    Directory of Open Access Journals (Sweden)

    Changhee Kim

    2016-07-01

    Full Text Available In light of the growing importance of data network quality in the wireless industry, this study analyzes and compares efficiencies in management, service quality, network quality, and market in the 4G Long Term Evolution (LTE wireless industry. For this purpose, a bootstrap data envelopment analysis (DEA model using representative U.S. wireless carriers as decision making units (DMUs was designed and conducted, with further verification through the Mann-Whitney U and Wilcoxon W test, to examine the differences in efficiency distribution. The results indicate that, in terms of efficiency distribution, network quality efficiency and market efficiency belongs to the same group as that which has high management efficiency. Based on these results, this paper suggests implications and strategic guidelines for wireless carriers for improvement in management efficiency.

  14. Band gap tunning in BN-doped graphene systems with high carrier mobility

    International Nuclear Information System (INIS)

    Using density functional theory, we present a comparative study of the electronic properties of BN-doped graphene monolayer, bilayer, trilayer, and multilayer systems. In addition, we address a superlattice of pristine and BN-doped graphene. Five doping levels between 12.5% and 75% are considered, for which we obtain band gaps from 0.02 eV to 2.43 eV. We demonstrate a low effective mass of the charge carriers

  15. Band gap tunning in BN-doped graphene systems with high carrier mobility

    KAUST Repository

    Kaloni, T. P.

    2014-02-17

    Using density functional theory, we present a comparative study of the electronic properties of BN-doped graphene monolayer, bilayer, trilayer, and multilayer systems. In addition, we address a superlattice of pristine and BN-doped graphene. Five doping levels between 12.5% and 75% are considered, for which we obtain band gaps from 0.02 eV to 2.43 eV. We demonstrate a low effective mass of the charge carriers.

  16. Contribution to the optimization of 4G mobile communications by means of advanced carrier aggregation strategies

    OpenAIRE

    Lema Rosas, María Ángel

    2015-01-01

    Mobile broadband subscriptions and data traffic have increasingly grown in the past years with the deployment of the 3G and 4G technologies and the massive use of mobile devices. In this sense, LTE-A has been presented as the next step in wireless communications where higher data rates are targeted and fully packet switched services are held. The ultimate goal of 4G and the forthcoming 5G technology is to increase the Quality of Experience (QoE) of users. In this context, several challenges o...

  17. Tuning superior solar cell performance of carrier mobility and absorption in perovskite CH3NH3GeCl3: A density functional calculations

    Science.gov (United States)

    Zhao, Yu-Qing; Wu, Li-Juan; Liu, Biao; Wang, Ling-Zhi; He, Peng-Bin; Cai, Meng-Qiu

    2016-05-01

    The solar cell based on hybrid organic-inorganic halide perovskite has received considerable attention. One of the most important issues in the pursuit of further developments in this area is to obtain both a high carrier mobility and an excellent ability of light adsorption. In this paper, we investigate the electronic structure and electronic effective masses of the new non-toxic material CH3NH3GeCl3 by first-principle calculations. The results show that the absorption efficiency of CH3NH3GeCl3 is more superior to that of CH3NH3PbI3 in short wavelength region. We trace this result to the ferroelectricity caused by the more serious octahedral GeCl6- distortion. We also discover a new relationship between the carrier effective masses anisotropy and the anisotropy of electronic density of states along three principal directions. Moreover, while applied the isotropic compressive pressure, the absorption efficiency and carrier mobility of CH3NH3GeCl3 in orthorhombic phase are improved greatly due to changes of electronic structure. We speculate that these are general results of tuning of the carrier mobility by controlling the band gap and the electronic occupation along different directions, to obtain both a high carrier mobility and an excellent ability of light adsorption.

  18. Multi-THz spectroscopy of mobile charge carriers in P3HT:PCBM on a sub-100 fs time scale

    DEFF Research Database (Denmark)

    Cooke, David G.; Krebs, Frederik C; Jepsen, Peter Uhd

    2013-01-01

    The dynamics of mobile charge carrier generation in polymer bulk heterojunction films is of vital importance to the development of more efficient organic photovoltaics. As with conventional semiconductors, the optical signatures of mobile carriers lie in the far-infrared (1-30 THz) although the...... spectroscopy of a polymer bulk heterojunction film P3HT:PCBM using a single-cycle, phase-locked and coherently detected multi-THz transient as a probe pulse following femtosecond excitation at 400 nm. By observing changes to the reflected THz transients from the film surface following photoexcitation, we can...

  19. Carrier mobility of iron oxide nanoparticles supported on ferroelectrics studied by Moessbauer spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Okamoto, T., E-mail: TAKUMI_OKAMOTO@denso.co.jp [DENSO Corporation (Japan); Kano, J. [Okayama University, Graduate School of Natural Science and Technology (Japan); Nakamura, S. [Teikyo University, Department of Science and Engineering (Japan); Fuwa, A. [Waseda University, Faculty of Science and Engineering (Japan); Otoyama, T.; Nakazaki, Y. [Nano Cube Japan Co., Ltd. (Japan); Hashimoto, H.; Takada, J. [Okayama University, Graduate School of Natural Science and Technology (Japan); Ito, M. [DENSO Corporation (Japan); Ikeda, N. [Okayama University, Graduate School of Natural Science and Technology (Japan)

    2013-04-15

    {sup 57}Fe Moessbauer spectroscopy was performed on two types of Fe oxide nanoparticles supported on a typical ferroelectric, BaTiO3. It was found that the valence state of FeO nanoparticles changed to a mixed 2+/3+ state at high temperature where BaTiO{sub 3} shows paraelectric behaviour. We attribute this phenomenon to the fluctuation of electric dipoles which realizes carrier injection into the Fe oxides. This is the first report which discusses a dynamical valence state of transition metal oxides supported on ferroelectrics.

  20. Carrier mobility of iron oxide nanoparticles supported on ferroelectrics studied by Mössbauer spectroscopy

    International Nuclear Information System (INIS)

    57Fe Mössbauer spectroscopy was performed on two types of Fe oxide nanoparticles supported on a typical ferroelectric, BaTiO3. It was found that the valence state of FeO nanoparticles changed to a mixed 2+/3+ state at high temperature where BaTiO3 shows paraelectric behaviour. We attribute this phenomenon to the fluctuation of electric dipoles which realizes carrier injection into the Fe oxides. This is the first report which discusses a dynamical valence state of transition metal oxides supported on ferroelectrics.

  1. Direct measurement of the magnetic field effects on carrier mobilities and recombination in tri-(8-hydroxyquinoline)-aluminum based light-emitting diodes

    OpenAIRE

    Li, Feng; Xin, Linyuan; Liu, Shiyong; Hu, Bin

    2010-01-01

    The magnetic field effects on the carrier mobilities and recombination in tri-(8-hydroxyquinoline)-aluminum (Alq3) based light-emitting diodes have been measured by the method of transient electroluminescence. It is confirmed that the magnetic field has no effect on the electron and hole mobilities in Alq3 layers and can decrease the electron-hole recombination coefficient. The results imply that the dominant mechanism for the magnetic field effects in Alq3 based light-emitting diodes is the ...

  2. Enhancement of carrier mobility in MoS2 field effect transistors by a SiO2 protective layer

    Science.gov (United States)

    Shao, Peng-Zhi; Zhao, Hai-Ming; Cao, Hui-Wen; Wang, Xue-Feng; Pang, Yu; Li, Yu-Xing; Deng, Ning-Qin; Zhang, Jing; Zhang, Guang-Yu; Yang, Yi; Zhang, Sheng; Ren, Tian-Ling

    2016-05-01

    Molybdenum disulfide is a promising channel material for field effect transistors (FETs). In this paper, monolayer MoS2 grown by chemical vapor deposition (CVD) was used to fabricate top-gate FETs through standard optical lithography. During the fabrication process, charged impurities and interface states are introduced, and the photoresist is not removed cleanly, which both limit the carrier mobility and the source-drain current. We apply a SiO2 protective layer, which is deposited on the surface of MoS2, in order to avoid the MoS2 directly contacting with the photoresist and the ambient environment. Therefore, the contact property between the MoS2 and the electrodes is improved, and the Coulomb scattering caused by the charged impurities and the interface states is reduced. Comparing MoS2 FETs with and without a SiO2 protective layer, the SiO2 protective layer is found to enhance the characteristics of the MoS2 FETs, including transfer and output characteristics. A high mobility of ˜42.3 cm2/V s is achieved, which is very large among the top-gate CVD-grown monolayer MoS2 FETs.

  3. Temperature dependence of the charge carrier mobility in gated quasi-one-dimensional systems

    OpenAIRE

    Gallos, L. K.; Movaghar, B.; Siebbeles, L.D.A.

    2003-01-01

    The many-body Monte Carlo method is used to evaluate the frequency dependent conductivity and the average mobility of a system of hopping charges, electronic or ionic on a one-dimensional chain or channel of finite length. Two cases are considered: the chain is connected to electrodes and in the other case the chain is confined giving zero dc conduction. The concentration of charge is varied using a gate electrode. At low temperatures and with the presence of an injection barrier, the mobilit...

  4. Charge carrier mobilities in organic semiconductor crystals based on the spectral overlap.

    Science.gov (United States)

    Stehr, Vera; Fink, Reinhold F; Deibel, Carsten; Engels, Bernd

    2016-09-01

    The prediction of substance-related charge-transport properties is important for the tayloring of new materials for organic devices, such as organic solar cells. Assuming a hopping process, the Marcus theory is frequently used to model charge transport. Here another approach, which is already widely used for exciton transport, is adapted to charge transport. It is based on the spectral overlap of the vibrational donor and acceptor spectra. As the Marcus theory it is derived from Fermi's Golden rule, however, it contains less approximations, as the molecular vibrations are treated quantum mechanically. In contrast, the Marcus theory reduces all vibrational degrees of freedom to one and treats its influence classically. The approach is tested on different acenes and predicts most of the experimentally available hole mobilities in these materials within a factor of 2. This represents a significant improvement to values obtained from Marcus theory which is qualitatively correct but frequently overestimates the mobilities by factors up to 10. Furthermore, the charge-transport properties of two derivatives of perylene bisimide are investigated. © 2016 Wiley Periodicals, Inc. PMID:27371816

  5. Measuring the complete cross-cell carrier mobility distributions in bulk heterojunction solar cells

    Science.gov (United States)

    Seifter, Jason; Sun, Yanming; Choi, Hyosung; Lee, Byoung Hoon; Heeger, Alan

    2015-03-01

    Carbon nanotube-enabled, vertical, organic field effect transistors (CN-VFETs) based on the small molecule dinaphtho[2,3-b:2',3'-f]thieno[3,2-b]thiophene (DNTT) have demonstrated high current, low-power operation suitable for driving active matix organic light emitting diode (AMOLED) displays. This performance is achieved without the need for costly high-resolution patterning, despite the low mobility of the organic semiconductor, by employing sub-micron channel widths, defined in the vertical devices by the thickness of the semiconducting layer. Replacing the thermally evaporated small molecule semiconductor with a solution-processed polymer would possibly further simplify the fabrication process and reduce manufacturing cost. Here we investigate several polymer systems as wide bandgap semiconducting channel layers for potentially air stable and transparent CN-VFETs. The field effect mobility and optical transparency of the polymer layers are determined, and the performance and air stability of CN-VFET devices are measured. A. S. gratefully acknowledges support from the National Science Foundation under DMR-1156737.

  6. Insights into the charge carrier terahertz mobility in polyfluorenes from large-scale atomistic simulations and time-resolved terahertz spectroscopy

    Czech Academy of Sciences Publication Activity Database

    Vukmirović, N.; Ponseca, C.S.; Němec, Hynek; Yartsev, A.; Sundström, V.

    2012-01-01

    Roč. 116, č. 37 (2012), s. 19665-1972. ISSN 1932-7447 Institutional research plan: CEZ:AV0Z10100520 Keywords : charge carrier mobility * time-resolved terahertz spectroscopy * multiscale atomistic calculations Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 4.814, year: 2012

  7. Application of helicon waves for contracthes local testing of homogeneity of certain narrow-band semiconductors according to density and mobility of free charge carriers

    International Nuclear Information System (INIS)

    Application of practically the single contactless local method today for determination of concentration and charge carrier mobility in narrow-band semiconductors of the CdxHg1-xTe(x∼0.2) type using helicons-circulating polarized electromagnetic waves propagating in the magnetized plasma of free charge carriers along the external magnetic field, is described. An installation for local testing of concentration and charge carrier mobility in narrow-band semiconductors is constructed and it has been used to study homogeneity of ternary CdxHg1-xTe solid solution samples of the n-type of conductivity at 77 K. This installation is shown to allow to carry out contactless expressive measurements of electrical properties of CdxHg1-xTe of n-type conductivity of high accuracy and locality, that gives the possibility to use it for testing material prepared in industry

  8. Percolation of Carbon Nanoparticles in Poly(3-Hexylthiophene Enhancing Carrier Mobility in Organic Thin Film Transistors

    Directory of Open Access Journals (Sweden)

    Chang-Hung Lee

    2014-01-01

    Full Text Available To improve the field-effect mobility of all-inkjet-printed organic thin film transistors (OTFTs, a composite material consisted of carbon nanoparticles (CNPs and poly(3-hexylthiophene (P3HT was reported by using homemade inkjet-printing system. These all-inkjet-printed composite OTFTs represented superior characteristics compared to the all-inkjet-printed pristine P3HT OTFTs. To investigate the enhancement mechanism of the blended materials, the percolation model was established and experimentally verified to illustrate the enhancement of the electrical properties with different blending concentrations. In addition, experimental results of OTFT contact resistances showed that both contact resistance and channel resistance were halved. At the same time, X-ray diffraction measurements, Fourier transform infrared spectra, ultraviolet-visible light, and photoluminescence spectra were also accomplished to clarify the material blending effects. Therefore, this study demonstrates the potential and guideline of carbon-based nanocomposite materials in all-inkjet-printed organic electronics.

  9. Field-effect measurements of mobility and carrier concentration of Cu2S colloidal quantum dot thin films after ligand exchange

    International Nuclear Information System (INIS)

    Colloidal quantum dots (CQDs) of copper sulfide (Cu2S), an earth-abundant semiconductor, have a number of intriguing applications that require knowledge of their electrical properties. Depending on stoichiometry, mobility, and surface treatment, applications include photoabsorbers for solar cells, tunable plasmonics, and counter-electrodes for polysulfate electrolytes. However, there have not been any direct measurements of electrical properties in Cu2S CQD thin films. Here, we exchange as synthesized dodecanethiol ligands with short ethanedithiol or ethylenediamine ligands to form thin films of coupled Cu2S CQDs. The mobility and carrier concentration were found to vary by ligand treatment from 10−5 cm2/Vs and 1019 holes/cm3 for ethanedithiol ligands to 10−3 cm2/Vs and 1020 holes/cm3 for ethylenediamine. These results are consistent with the carrier concentrations inferred from sub-bandgap surface-plasmon-resonances measured by infrared spectroscopy. These results will be useful when designing Cu2S materials for future applications. - Highlights: • Colloidal Cu2S quantum dots were synthesized and characterized. • Ligand exchange was performed to alter the Cu2S nanocrystal properties. • Ligand exchange was studied using photoluminescence and infrared spectroscopy. • Field effect mobility and carrier concentration were directly measured. • Carrier concentration was compared to estimates from surface plasmon resonances

  10. Simultaneous enhancement of carrier mobility and concentration via tailoring of Al-chemical states in Al-ZnO thin films

    International Nuclear Information System (INIS)

    Simultaneously achieving higher carriers concentration and mobility is a technical challenge against up-scaling the transparent-conductive performances of transparent-conductive oxides. Utilizing one order higher dense (∼1 × 1011 cm−3) plasmas (in comparison to the conventional direct current plasmas), highly c-axis oriented Al-doped ZnO films have been prepared with precise control over relative composition and chemical states of constituting elements. Tailoring of intrinsic (O vacancies) and extrinsic (ionic Al and zero-valent Al) dopants provide simultaneous enhancement in mobility and concentration of charge carriers. Room-temperature resistivity as low as 4.89 × 10−4 Ω cm along the carrier concentration 5.6 × 1020 cm−3 is obtained in 200 nm thick transparent films. Here, the control of atomic Al reduces the charge trapping at grain boundaries and subdues the effects of grain boundary scattering. A mechanism based on the correlation between electron-hole interaction and carrier mobility is proposed for degenerately doped wide band-gap semiconductors

  11. Field-effect measurements of mobility and carrier concentration of Cu{sub 2}S colloidal quantum dot thin films after ligand exchange

    Energy Technology Data Exchange (ETDEWEB)

    Brewer, Adam S.; Arnold, Michael S., E-mail: msarnold@wisc.edu

    2014-09-30

    Colloidal quantum dots (CQDs) of copper sulfide (Cu{sub 2}S), an earth-abundant semiconductor, have a number of intriguing applications that require knowledge of their electrical properties. Depending on stoichiometry, mobility, and surface treatment, applications include photoabsorbers for solar cells, tunable plasmonics, and counter-electrodes for polysulfate electrolytes. However, there have not been any direct measurements of electrical properties in Cu{sub 2}S CQD thin films. Here, we exchange as synthesized dodecanethiol ligands with short ethanedithiol or ethylenediamine ligands to form thin films of coupled Cu{sub 2}S CQDs. The mobility and carrier concentration were found to vary by ligand treatment from 10{sup −5} cm{sup 2}/Vs and 10{sup 19} holes/cm{sup 3} for ethanedithiol ligands to 10{sup −3} cm{sup 2}/Vs and 10{sup 20} holes/cm{sup 3} for ethylenediamine. These results are consistent with the carrier concentrations inferred from sub-bandgap surface-plasmon-resonances measured by infrared spectroscopy. These results will be useful when designing Cu{sub 2}S materials for future applications. - Highlights: • Colloidal Cu2S quantum dots were synthesized and characterized. • Ligand exchange was performed to alter the Cu2S nanocrystal properties. • Ligand exchange was studied using photoluminescence and infrared spectroscopy. • Field effect mobility and carrier concentration were directly measured. • Carrier concentration was compared to estimates from surface plasmon resonances.

  12. Low Exciton-Phonon Coupling, High Charge Carrier Mobilities, and Multiexciton Properties in Two-Dimensional Lead, Silver, Cadmium, and Copper Chalcogenide Nanostructures.

    Science.gov (United States)

    Ding, Yuchen; Singh, Vivek; Goodman, Samuel M; Nagpal, Prashant

    2014-12-18

    The development of two-dimensional (2D) nanomaterials has revealed novel physical properties, like high carrier mobilities and the tunable coupling of charge carriers with phonons, which can enable wide-ranging applications in optoelectronic and thermoelectric devices. While mechanical exfoliation of graphene and some transition metal dichalcogenides (e.g., MoS2, WSe2) has enabled their fabrication as 2D semiconductors and integration into devices, lack of similar syntheses for other 2D semiconductor materials has hindered further progress. Here, we report measurements of fundamental charge carrier interactions and optoelectronic properties of 2D nanomaterials made from two-monolayers-thick PbX, CdX, Cu2X, and Ag2X (X = S, Se) using colloidal syntheses. Extremely low coupling of charge carriers with phonons (2-6-fold lower than bulk and other low-dimensional semiconductors), high carrier mobilities (0.2-1.2 cm(2) V(-1) s(-1), without dielectric screening), observation of infrared surface plasmons in ultrathin 2D semiconductor nanostructures, strong quantum-confinement, and other multiexcitonic properties (different phonon coupling and photon-to-charge collection efficiencies for band-edge and higher-energy excitons) can pave the way for efficient solution-processed devices made from these 2D nanostructured semiconductors. PMID:26273976

  13. Influence of Blend Ratio and Processing Additive on Free Carrier Yield and Mobility in PTB7:PC71BM Photovoltaic Solar Cells

    Science.gov (United States)

    2016-01-01

    Charge separation and extraction dynamics were investigated in high-performance bulk heterojunction solar cells made from the polymer PTB7 and the soluble fullerene PC71BM on a broad time scale from subpicosecond to microseconds using ultrafast optical probing of carrier drift and the integral-mode photocurrent measurements. We show that the short circuit current is determined by the separation of charge pairs into free carriers, which is strongly influenced by blend composition. This separation is found to be efficient in fullerene-rich blends where a high electron mobility of >0.1 cm2 V–1 s–1 is observed in the first 10 ps after excitation. Morphology optimization using the solvent additive 1,8-diiodooctane (DIO) doubles the charge pair separation efficiency and the short-circuit current. Carrier extraction at low internal electric field is slightly faster from the cells prepared with DIO, which can reduce recombination losses and enhance a fill factor. PMID:27293495

  14. Influence of structural defects in subsurface layers of silicon on charge carrier mobility in the channel of MOS-transistors threshold voltage

    International Nuclear Information System (INIS)

    The influence of structural imperfections, the impurity composition, and the doping inhomogeneity on the basic parameters of the I - V characteristics of MOS-transistors has been found out with aid of modern research methods. Oxygen and carbon are the basic impurities in initial and oxidized silicons. Oxygen reveals electrical activity and influences the parameters of structural defects that, in turn, affect the charge carrier mobility and the threshold voltage

  15. Al{sub x}Ga{sub 1−x}As/GaAs(100) hetermostructures with anomalously high carrier mobility

    Energy Technology Data Exchange (ETDEWEB)

    Seredin, P. V., E-mail: paul@phys.vsu.ru; Goloshchapov, D. L.; Lenshin, A. S.; Ternovaya, V. E. [Voronezh State University (Russian Federation); Arsentyev, I. N., E-mail: arsentyev@mail.ioffe.ru; Nikolaev, D. N.; Tarasov, I. S.; Shamakhov, V. V. [Russian Academy of Sciences, Ioffe Institute (Russian Federation); Popov, A. V. [Research Institute of Electronics (Russian Federation)

    2015-08-15

    Structural and spectroscopic methods are used to study the epitaxial layers of n-type Al{sub x}Ga{sub 1−x}As solid solutions produced by the metal-organic chemical vapor deposition method. It is shown that, when Al{sub x}Ga{sub 1−x}As solid solutions are doped with carbon to a level of (1.2–6.7) × 10{sup 17} cm{sup −3}, the electron mobility is anomalously high for the given impurity concentration and twice exceeds the calculated value. It is assumed that the ordered arrangement of carbon in the metal sublattice of the solid solution leads to a change in the average distance between impurity ions, i.e., to an increase in the mean free path of the carriers and, consequently, in the carrier mobility. The observed effect has immediate practical importance in the search for various technological ways of increasing the operating speed of functional elements of modern optoelectronic devices. The effect of the anomalously high carrier mobility in the epitaxial layer of a heteropair opens up new opportunities for the development of new structures on the basis of Al{sub x}Ga{sub 1−x}As compounds.

  16. Interplay between hopping and band transport in high-mobility disordered semiconductors at large carrier concentrations: The case of the amorphous oxide InGaZnO

    Science.gov (United States)

    Fishchuk, I. I.; Kadashchuk, A.; Bhoolokam, A.; de Jamblinne de Meux, A.; Pourtois, G.; Gavrilyuk, M. M.; Köhler, A.; Bässler, H.; Heremans, P.; Genoe, J.

    2016-05-01

    We suggest an analytic theory based on the effective medium approximation (EMA) which is able to describe charge-carrier transport in a disordered semiconductor with a significant degree of degeneration realized at high carrier concentrations, especially relevant in some thin-film transistors (TFTs), when the Fermi level is very close to the conduction-band edge. The EMA model is based on special averaging of the Fermi-Dirac carrier distributions using a suitably normalized cumulative density-of-state distribution that includes both delocalized states and the localized states. The principal advantage of the present model is its ability to describe universally effective drift and Hall mobility in heterogeneous materials as a function of disorder, temperature, and carrier concentration within the same theoretical formalism. It also bridges a gap between hopping and bandlike transport in an energetically heterogeneous system. The key assumption of the model is that the charge carriers move through delocalized states and that, in addition to the tail of the localized states, the disorder can give rise to spatial energy variation of the transport-band edge being described by a Gaussian distribution. It can explain a puzzling observation of activated and carrier-concentration-dependent Hall mobility in a disordered system featuring an ideal Hall effect. The present model has been successfully applied to describe experimental results on the charge transport measured in an amorphous oxide semiconductor, In-Ga-Zn-O (a-IGZO). In particular, the model reproduces well both the conventional Meyer-Neldel (MN) compensation behavior for the charge-carrier mobility and inverse-MN effect for the conductivity observed in the same a-IGZO TFT. The model was further supported by ab initio calculations revealing that the amorphization of IGZO gives rise to variation of the conduction-band edge rather than to the creation of localized states. The obtained changes agree with the one we

  17. Enhanced carrier mobility and direct tunneling probability of biaxially strained Ge{sub 1−x}Sn{sub x} alloys for field-effect transistors applications

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Lei; Liang, Renrong, E-mail: liangrr@tsinghua.edu.cn, E-mail: junxu@tsinghua.edu.cn; Wang, Jing; Xu, Jun, E-mail: liangrr@tsinghua.edu.cn, E-mail: junxu@tsinghua.edu.cn [Tsinghua National Laboratory for Information Science and Technology, Institute of Microelectronics, Tsinghua University, Beijing 100084 (China)

    2015-05-14

    The carrier transport and tunneling capabilities of biaxially strained Ge{sub 1−x}Sn{sub x} alloys with (001), (110), and (111) orientations were comprehensively investigated and compared. The electron band structures of biaxially strained Ge{sub 1−x}Sn{sub x} alloys were calculated by the nonlocal empirical pseudopotential method and the modified virtual crystal approximation was adopted in the calculation. The electron and hole effective masses at the band edges were extracted using a parabolic line fit. It is shown that the applied biaxial strain and the high Sn composition are both helpful for the reduction of carrier effective masses, which leads to the enhanced carrier mobility and the boosted direct band-to-band-tunneling probability. Furthermore, the strain induced valance band splitting reduces the hole interband scattering, and the splitting also results in the significantly enhanced direct tunneling rate along the out-of-plane direction compared with that along the in-plane direction. The biaxially strained (111) Ge{sub 1−x}Sn{sub x} alloys exhibit the smallest band gaps compared with (001) and (110) orientations, leading to the highest in-plane and out-of-plane direct tunneling probabilities. The small effective masses on (110) and (111) planes in some strained conditions also contribute to the enhanced carrier mobility and tunneling probability. Therefore, the biaxially strained (110) and (111) Ge{sub 1−x}Sn{sub x} alloys have the potential to outperform the corresponding (001) Ge{sub 1−x}Sn{sub x} devices. It is important to optimize the applied biaxial strain, the Sn composition, and the substrate orientation for the design of high performance Ge{sub 1−x}Sn{sub x} field-effect transistors.

  18. Negative differential mobility for negative carriers as revealed by space charge measurements on crosslinked polyethylene insulated model cables

    International Nuclear Information System (INIS)

    Among features observed in polyethylene materials under relatively high field, space charge packets, consisting in a pulse of net charge that remains in the form of a pulse as it crosses the insulation, are repeatedly observed but without complete theory explaining their formation and propagation. Positive charge packets are more often reported, and the models based on negative differential mobility(NDM) for the transport of holes could account for some charge packets phenomenology. Conversely, NDM for electrons transport has never been reported so far. The present contribution reports space charge measurements by pulsed electroacoustic method on miniature cables that are model of HVDC cables. The measurements were realized at room temperature or with a temperature gradient of 10 °C through the insulation under DC fields on the order 30–60 kV/mm. Space charge results reveal systematic occurrence of a negative front of charges generated at the inner electrode that moves toward the outer electrode at the beginning of the polarization step. It is observed that the transit time of the front of negative charge increases, and therefore the mobility decreases, with the applied voltage. Further, the estimated mobility, in the range 10−14–10−13 m2 V−1 s−1 for the present results, increases when the temperature increases for the same condition of applied voltage. The features substantiate the hypothesis of negative differential mobility used for modelling space charge packets

  19. Negative differential mobility for negative carriers as revealed by space charge measurements on crosslinked polyethylene insulated model cables

    Science.gov (United States)

    Teyssedre, G.; Vu, T. T. N.; Laurent, C.

    2015-12-01

    Among features observed in polyethylene materials under relatively high field, space charge packets, consisting in a pulse of net charge that remains in the form of a pulse as it crosses the insulation, are repeatedly observed but without complete theory explaining their formation and propagation. Positive charge packets are more often reported, and the models based on negative differential mobility(NDM) for the transport of holes could account for some charge packets phenomenology. Conversely, NDM for electrons transport has never been reported so far. The present contribution reports space charge measurements by pulsed electroacoustic method on miniature cables that are model of HVDC cables. The measurements were realized at room temperature or with a temperature gradient of 10 °C through the insulation under DC fields on the order 30-60 kV/mm. Space charge results reveal systematic occurrence of a negative front of charges generated at the inner electrode that moves toward the outer electrode at the beginning of the polarization step. It is observed that the transit time of the front of negative charge increases, and therefore the mobility decreases, with the applied voltage. Further, the estimated mobility, in the range 10-14-10-13 m2 V-1 s-1 for the present results, increases when the temperature increases for the same condition of applied voltage. The features substantiate the hypothesis of negative differential mobility used for modelling space charge packets.

  20. Mobilities

    DEFF Research Database (Denmark)

    . The selection will cover diverse topics such as theories, concepts, methods, and approaches as well as it will explore various modes of mobilities and the relationship to everyday life practices. The selection also covers the ‘politics of mobilities’ from local urban planning schemes to geopolitical...... issues of refugees and environmental degradation. The spaces and territories marked by mobilities as well as the sites marked by the bypassing of such are explored. Moreover, the architectural and technological dimensions to infrastructures and sites of mobilities will be included as well as the issues...... of power, social exclusion, consumption, surveillance and mobilities history to mention some of the many themes covered by this reference work. This new title will focus on the academic contributions to this understanding by primarily focusing on works and publications in the aftermath of the seminal...

  1. Negative differential mobility for negative carriers as revealed by space charge measurements on crosslinked polyethylene insulated model cables

    Energy Technology Data Exchange (ETDEWEB)

    Teyssedre, G., E-mail: gilbert.teyssedre@laplace.univ-tlse.fr; Laurent, C. [Université de Toulouse, UPS, INPT, LAPLACE (Laboratoire Plasma et Conversion d' Energie), 118 route de Narbonne, F-31062 Toulouse cedex 9 (France); CNRS, LAPLACE, F-31062 Toulouse (France); Vu, T. T. N. [Université de Toulouse, UPS, INPT, LAPLACE (Laboratoire Plasma et Conversion d' Energie), 118 route de Narbonne, F-31062 Toulouse cedex 9 (France); Electric Power University, 235 Hoang Quoc Viet, 10000 Hanoi (Viet Nam)

    2015-12-21

    Among features observed in polyethylene materials under relatively high field, space charge packets, consisting in a pulse of net charge that remains in the form of a pulse as it crosses the insulation, are repeatedly observed but without complete theory explaining their formation and propagation. Positive charge packets are more often reported, and the models based on negative differential mobility(NDM) for the transport of holes could account for some charge packets phenomenology. Conversely, NDM for electrons transport has never been reported so far. The present contribution reports space charge measurements by pulsed electroacoustic method on miniature cables that are model of HVDC cables. The measurements were realized at room temperature or with a temperature gradient of 10 °C through the insulation under DC fields on the order 30–60 kV/mm. Space charge results reveal systematic occurrence of a negative front of charges generated at the inner electrode that moves toward the outer electrode at the beginning of the polarization step. It is observed that the transit time of the front of negative charge increases, and therefore the mobility decreases, with the applied voltage. Further, the estimated mobility, in the range 10{sup −14}–10{sup −13} m{sup 2} V{sup −1} s{sup −1} for the present results, increases when the temperature increases for the same condition of applied voltage. The features substantiate the hypothesis of negative differential mobility used for modelling space charge packets.

  2. Electrical transport in a disordered medium: NMR measurement of diffusivity and electrical mobility of ionic charge carriers.

    Science.gov (United States)

    Heil, S R; Holz, M

    1998-11-01

    Electrical transport in porous media plays an important role in many fields of pure and applied science. The basic microscopic processes of the charge transport have attracted considerable theoretical interest for a long time. However, on a microscopic level there was up to now no experimental access to this problem. In the present paper we demonstrate, by using a suited porous system, that two combined NMR methods can offer such a first experimental access. We apply common PFG NMR methods and the special electrophoretic NMR (ENMR) technique for the measurement of self-diffusion coefficient D+ and electric mobility u+ of a cation ((C4H9)+4) in a disordered gel-like medium (Sephadex LH-20) filled with electrolyte solution. We find a, qualitatively expected, observation time-dependence of D+, but for the first time such a time-dependence is also observed for u+, which means the detection of the phenomenon of "anomalous field assisted diffusion" or "anomalous mobility." For the measurement of the short-time behavior of the mobility a new pulse sequence is presented. The time-dependent mobilities were measured at three different external electrical fields E. From the long-time behavior of D+, u+, and DH2O three independent values for the tortuosity T of the porous system could be derived. We find equality of the tortuosities T(D+) and T(u+), which represents a first experimental proof of the validity of the Einstein relation (D+ approximately u+) in a disordered medium. Finally, we discuss advantages of the possible use of "anomalous field assisted diffusion" over the commonly used "anomalous diffusion" in morphology studies by dynamic imaging in porous media. PMID:9799669

  3. Effects of excess oxygen introduced during sputter deposition on carrier mobility in as-deposited and postannealed indium-tin-oxide films

    International Nuclear Information System (INIS)

    Electrical and structural properties of indium-tin-oxide (ITO) films with various Sn concentrations deposited under a high oxygen partial pressure were examined to find out how the excess oxygen behaves as a scattering and trapping center of electron carriers and to show evidence that excess oxygen is weakly bound with Sn4+ ions on In3+ sites with single-charge SnIn . ITO films with Sn concentrations of 1-25 wt % were deposited on glass substrates by rf sputtering under various oxygen concentrations in the discharge gas (0.3%-100%); the substrate temperature was kept at 773 K during deposition. With increasing O2 flow ratio in the discharge gas from 0.3% to 100%, the Hall mobility and the carrier density were found to decrease from ∼40 to ∼20 cm2 V-1 s-1 and from ∼5.0x1020 to ∼2.0x1018 cm-3, respectively. The dependence of the slope of mobility-temperature curve on the O2 flow ratio and Sn concentration has been examined. For high Sn concentration, the slope changes from negative to positive as the O2 flow rate increases. The slope of the curve for a film with Sn concentration of 8 wt % deposited at an O2 flow ratio of 100% changes from positive to negative after postannealing at 473 K for 30 min. in N2. These results suggest that the oxygen attaches weakly to Sn4+ and that the oxygen plays a role in the scattering and trapping center. It is also found that oxygen ions mainly exist not in interstitial quasianion sites but in the grain boundaries because of the constant lattice parameter after annealing

  4. Recovery of synthetic dye from simulated wastewater using emulsion liquid membrane process containing tri-dodecyl amine as a mobile carrier

    International Nuclear Information System (INIS)

    Highlights: ► The emulsion liquid membrane process for synthetic reactive dyes recovery was examined. ► Mobile carriers of tri-dodycylamine and salicyclic acid was used in formulation to remove the reactive dyes from simulated wastewater. ► Almost 100% of dye was extracted and recovered in receiving phase. ► An electrical field was used to breakdown the emulsion to separate the liquid membrane and receiving/recovery phase. - Abstract: The extraction of Red 3BS reactive dye from aqueous solution was studied using emulsion liquid membrane (ELM). ELM is one of the processes that have very high potential in treating industrial wastewater consisting of dyes. In this research, Red 3BS reactive dye was extracted from simulated wastewater using tridodecylamine (TDA) as the carrier agent, salicyclic acid (SA) to protonate TDA, sodium chloride as the stripping agent, kerosene as the diluent and SPAN 80 as emulsifier. Experimental parameters investigated were salicyclic acid concentration, extraction time, SPAN 80 concentration, sodium chloride concentration, TDA concentration, agitation speed, homogenizer speed, emulsifying time and treat ratio. The results show almost 100% of Red 3BS was removed and stripped in the receiving phase at the optimum condition in this ELM system. High voltage coalesce was applied to break the emulsion hence, enables recovery of Red 3BS in the receiving phase.

  5. Polymer-assisted solution processing of Mo-doped indium oxide thin films: high-mobility and carrier-scattering mechanisms

    Science.gov (United States)

    Vishwanath, Sujaya Kumar; Cho, Kuk Young; Kim, Jihoon

    2016-04-01

    Mo-doped indium oxide (MIO) transparent conducting films have been prepared by a polymer-assisted solution (PAS) process. Both Mo- and In-PASs have been formulated by coordinating Mo- and In-anionic complexes with polyethyleneimine. The final MIO-PAS coating solution was prepared by adding Mo-PAS and In-PAS with Mo concentration in solution ranging from 0 at% to 2.5 at%. The structural, optical and electrical properties of MIO films spin-coated on the glass substrates were characterized. The optimum Mo concentration leading to the best electrical and optical properties was 1.5 at%, showing a low resistivity of 3.9  ×  10-3 Ω  ṡ  cm with high mobility of 43 cm2 V-1 s-1 and high transmittance from visible to near infrared regions. The carrier-transport mechanism in the PAS-processed MIO film was investigated by applying a theoretical scattering model (Brook-Herring-Dingle theory) to Hall mobility data. The scattering model confirms that the ionized and neutral impurities play important roles as dominant scattering centers in the PAS-processed MIO films.

  6. Syntheses, phase behavior, supramolecular chirality, and field-effect carrier mobility of asymmetrically end-capped mesogenic oligothiophenes.

    Science.gov (United States)

    Meng, Qingwei; Sun, Xiao-Hua; Lu, Zhengyu; Xia, Ping-Fang; Shi, Zehua; Chen, Dongzhong; Wong, Man Shing; Wakim, Salem; Lu, Jianping; Baribeau, Jean-Marc; Tao, Ye

    2009-01-01

    phase of the single end-capped oligothiophenes can be utilized to improve field-effect charge mobility. C(10)O-Ar-OT(4)-H showed a hole mobility of 0.07 cm(2) V(-1) s(-1) when deposited on octyltrichlorosilane-treated substrates at 140 degrees C and the on/off current ratios reached 5 x 10(5); on the other hand, its mobility was only 8 x 10(-3) cm(2) V(-1) s(-1) on the same substrate when deposited at room temperature. PMID:19219863

  7. Drift-Diffusion Modeling of the Effects of Structural Disorder and Carrier Mobility on the Performance of Organic Photovoltaic Devices

    Science.gov (United States)

    Finck, Benjamin Y.; Schwartz, Benjamin J.

    2015-09-01

    We probe the effects of structural disorder on the performance of organic photovoltaic (OPV) devices via drift-diffusion modeling. We utilize ensembles of spatially disordered one-dimensional mobility profiles to approximate the three-dimensional structural disorder present in actual devices. Each replica in our ensemble approximates one high-conductivity pathway through the three-dimensional network(s) present in a polymer-based bulk heterojunction solar cell, so that the ensemble-averaged behavior provides a good approximation to a full three-dimensional structurally disordered device. Our calculations show that the short-circuit current, fill factor, and power conversion efficiency of simulated devices are all negatively impacted by the inclusion of structural disorder, but that the open-circuit voltage is nearly impervious to structural defects. This is in contrast to energetic disorder, where previous studies found that spatial variation in the energy in OPV active layers causes a decrease in the open-circuit voltage. We also show that structural disorder causes the greatest detriment to device performance for feature sizes between 2 and 10 nm. Since this is on the same length scale as the fullerene crystallites in experimental devices, it suggests both that controlling structural disorder is critical to the performance of OPV devices and that the effects of structural disorder should be included in future drift-diffusion modeling studies of organic solar cells.

  8. Investigation of carrier density and mobility in microcrystalline silicon alloys using Hall effect and thermopower measurements; Untersuchung der Ladungstraegerkonzentration und -beweglichkeit in mikrokristallinen Siliziumlegierungen mit Hall-Effekt und Thermokraft

    Energy Technology Data Exchange (ETDEWEB)

    Sellmer, Christian

    2012-08-31

    The electronic properties of amorphous and microcrystalline silicon layers in thin-film solar cells significantly affect the efficiency of solar cells. An important property of the individual layer is the electronic transport, which is described by the variables conductivity, photoconductivity, mobility, and carrier concentration. In the past, individual characterization methods were typically used to determine the electronic properties. Using the combination of Hall effect, conductivity, and thermoelectric power measurements additional variables can be derived, such as the effective density of states at the valence and conduction band edge, making a more detailed description of the material possible. To systematically study the electronic properties - in particular carrier mobility and carrier concentration - various series of silicon films are prepared for this work including microcrystalline silicon layers of different doping and crystallinity and a series of silicon films where the Fermi level is moved by irradiation with high energy electrons on one and the same sample. The results show that the transition from amorphous to microcrystalline transport is relatively abrupt. If the electron transport takes place in only amorphous regions, it is marked by the sign anomaly of the Hall effect. If a continuous crystalline path exists, the electronic properties are dominated by the crystalline volume fraction. The results of the measurements of silicon layers are compared with those of microcrystalline silicon carbide samples. Silicon carbide is especially interesting for future applications in thin-film solar cells due to high transparency and high conductivity. It is shown that the effective density of states at the valence and conduction band edge as a function of temperature in p- and n-type microcrystalline silicon and silicon carbide samples largely coincide with those of crystalline silicon or silicon carbide. A square root shaped profile of the density of

  9. Study of carrier mobility of N,N′-diphenyl-N,N′bis(1,1′-biphenyl)-4,4′-diamine (NPB) by transmission line model of impedance spectroscopy

    International Nuclear Information System (INIS)

    As a powerful method for electrical measurement, impedance spectroscopy and admittance spectroscopy methods began to receive more and more attention in organic electronics research scholars. It demonstrates outstanding advantages especially in the measurement of the mobility of the charge carriers. In this paper, the hole mobility of N,N′-diphenyl-N,N′bis(1,1′-biphenyl)-4,4′-diamine (NPB) was studied by the transmission line model based on impedance spectroscopy. According to energy level of the materials of each layer, a hole-only current device with single-layer structure of indium-tin-oxide(ITO)/NPB/Ag was designed and fabricated, and its Nyquist diagram was measured at different biased voltage. The corresponding transmission line model was proposed according to the device structure and the materials, which was used to the fitting procedure to get the transfer time of the carrier. At last, the carrier mobility was obtained from the transfer time. The results showed that the hole mobility of NPB obtained by transmission line model was in line with the Poole–Freckle model. The zero-field mobility and the pre-exponential factor was further achieved to be 3.9 × 10−5 cm2 · V−1 · s−1 and 6.8 × 10−3(V/cm)−1/2, respectively. Moreover, the method can also be easily used for the study of the electron transport properties of the organic semiconductor. - Highlights: • Hole mobility of N,N′-diphenyl-N,N′bis(1,1′-biphenyl)-4,4′-diamine (NPB) was studied by the transmission line model • The results was in line with the Poole-Freckle model • Zero-field mobility and the pre-exponential factor was further achieved

  10. The emergence of iPhone and its impact on mobile carriers and handset manufacturers: The case of USA, Europe and Japan

    OpenAIRE

    Terada, Shinichiro

    2012-01-01

    This paper investigates the impact of iPhone, a representative of smartphones, on telecommunications carriers and handset manufacturers in U.S.A, Europe, and Japan. We choose the event study methodology to evaluate the impact of iPhone emergence. We also look at the financial profit of the carriers and manufacturers in order to confirm the financial impact of iPhone emergence. Our research question is How does the emergence of iPhone generate the impact on the telecommunications carriers and ...

  11. Charge carrier transport at the nanoscale: Electron and hole transport in self-assembled discotic liquid crystals: Mobile ionic charges in nanocomposite solid electrolytes

    NARCIS (Netherlands)

    Haverkate, L.A.

    2013-01-01

    This thesis explores some fundamental aspects of charge carrier transport at the nanoscale. The study is divided in two parts. In the first part, the structural, dynamical and vibrational properties of discotic liquid crystals are studied in relation to the potential of these self-assembled ‘mesopha

  12. Radionuclide carriers

    International Nuclear Information System (INIS)

    A new carrier for radionuclide technetium 99m has been prepared for scintiscanning purposes. The new preparate consists of physiologically acceptable water-insoluble Tcsup(99m)-carrier containing from 0.2 to 0.8 weight percent of stannic ion as reductor, bound to an anionic starch derivative with about 1-20% of phosphate substituents. (EG)

  13. Aircraft Carriers

    DEFF Research Database (Denmark)

    Nødskov, Kim; Kværnø, Ole

    the majority of its foreign trade, as well as its oil imports, upon which the country is totally dependent. China therefore has good reasons for acquiring an aircraft carrier to enable it to protect its national interests. An aircraft carrier would also be a prominent symbol of China’s future status...... information is pieced together, then a picture is created of a Chinese aircraft carrier program, where Varyag will be made operational for training purposes. With this as the model, China will build a similar sized carrier themselves. If this project does become a reality, then it will take many years for...... Kuznetsov carrier. The SU-33 is, in its modernized version, technologically at the same level as western combat aircraft in both the offensive as well as the defensive roles. But Russia and China currently have an arms trade 6 dispute that is likely to prevent a deal, unless the dispute is resolved. As an...

  14. The influence of orientations and external electric field on charge carrier mobilities in CuPc and F16CuPc films on highly ordered pyrolytic graphite and octane-1-thiol terminated Au(111) substrates.

    Science.gov (United States)

    Chen, Shuang; Ma, Jing

    2010-10-14

    The lying-down and standing-up CuPc and F(16)CuPc films on HOPG (highly ordered pyrolytic graphite) and C8-SAM/Au(111) (octane-1-thiol terminated Au(111)) substrates are investigated by using a hybrid strategy combing the molecular dynamic (MD) simulations with density functional theory (DFT) calculations, in order to understand the influence of packing orientation on charge carrier mobilities. On the basis of the periodic slab model and consistent-valence force field, MD simulations show the populations of various packing configurations and radial distribution of intermolecular distance in the films at room temperature. It is also demonstrated that the external electric field (parallel or perpendicular to the substrate) perturbs the intermolecular distances in CuPc and F(16)CuPc films, especially for the slipped edge-to-face stackings. DFT calculations are then used to evaluate two key charge-transfer parameters, reorganization energy and transfer integral. An electrostatics embedding model is employed to approximately consider the external electrostatics contributions to reorganization energy. The thermal-averaged mobility is consequently estimated by taking account of both electronic structures of charge-hopping pairs and dynamic fluctuations in film morphologies under various experimental conditions. It is found that CuPc has smaller reorganization energy and larger hole (electron) mobilities than F(16)CuPc. Under the external electric field of 10(4)-10(7) V cm(-1), both hole and electron mobilities of CuPc and F(16)CuPc films would decrease to 1-3 orders of magnitude. CuPc (F(16)CuPc) films show substantial orientation dependence of mobilities on the ratio of standing-up versus lying-down orientations falling in the range of 10-1000. PMID:20714578

  15. Cadmium (II) and lead (II) transport in a polymer inclusion membrane using tributyl phosphate as mobile carrier and CuFeO2 as a polarized photo electrode

    International Nuclear Information System (INIS)

    In this work, a development of polymeric inclusion membranes for the cations separation is reported. The membrane was made up of cellulose triacetate (CTA) with a tributyl phosphate (TBP) incorporated into the polymer as metal ions carrier. The transport of lead (II) and cadmium (II) ions in two membrane systems polymer inclusion membrane (PIM), PIM coupled with photo-chemical electrode using TBP as carrier and 2-nitro phenyl octyl ether (NPOE) or tris ethylhexyl phosphate (TEHP) as plasticizer have been investigated. The membranes: polymer + plasticizer + carrier were synthesized and characterized by FTIR, X-ray diffraction and scanning electron microscopy (SEM). Transports of lead and cadmium have been studied using these systems and the results were compared to commercial cation exchange membrane (CRA). The obtained results showed that for Pb2+ ion, the concentrations of the strip phase increases using synthesized membranes. The conduction band of the delafossite CuFeO2 (-1.25 VSCE) yields a thermodynamically M2+ (=Pb2+, Cd2+) photo electrodeposition and speeds up the diffusion process. In all the cases, the potential of the electrode M/M2+ in the feed compartment increases until a maximum value, reached at ∼100 min above which it undergoes a diminution.

  16. Aircraft Carriers

    DEFF Research Database (Denmark)

    Nødskov, Kim; Kværnø, Ole

    as a great power in Asia and will balance the carrier acquisitions of the United States, the United Kingdom, Russia and India. China’s current military strategy is predominantly defensive, its offensive elements being mainly focused on Taiwan. If China decides to acquire a large carrier with...... offensive capabilities, then the country will also acquire the capability to project military power into the region beyond Taiwan, which it does not possess today. In this way, China will have the military capability to permit a change of strategy from the mainly defensive, mainland, Taiwan-based strategy...... to a more assertive strategy, with potentially far-reaching consequences for the countries of the region. The Chinese have bought several retired carriers, which they have studied in great detail. The largest is the Russian-built carrier Varyag of the Kuznetsov class, which today is anchored in the...

  17. Mobilities Mobilities

    Directory of Open Access Journals (Sweden)

    César Pompeyo

    2011-12-01

    Full Text Available Urry, John (2007 Mobilities.Oxford: Polity Press.Urry, John (2007 Mobilities.Oxford: Polity Press.John Urry (1946-, profesor en la Universidad de Lancaster, es un sociólogo de sobra conocido y altamente reputado en el panorama internacional de las ciencias sociales. Su dilatada carrera, aparentemente dispersa y diversificada, ha seguido senderos bastante bien definidos dejando tras de sí un catálogo extenso de obras sociológicas de primer nivel. Sus primeros trabajos se centraban en el campo de la teoría social y la filosofía de las ciencias sociales o de la sociología del poder [...

  18. cdma移动通信多载波边界优化规划浅析%The Optimal Planning of cdma Mobile Multi-carrier Border

    Institute of Scientific and Technical Information of China (English)

    张浩; 赵志强

    2011-01-01

    本文阐述由于多载波边界设置不合理导致硬切换区域位于高话务区域,造成该区域高硬切换概率,导致掉话问题的处理描述。%This paper describes the set as multi-carrier border region caused by an irrational hard switching in high-traffic area,resulting in hard switching in the region of high probability,lead to dropped calls problem handling description.

  19. Design and Development of a Mechanical Carrier for Mobile Robot (with rough surface/terrain movement features)- Extension of KINPOE Robot Project for Application at K-1

    International Nuclear Information System (INIS)

    During plant (KANUPP) operation, it is difficult or nearly impossible to access and monitor (high) radiation areas where some abnormal condition has to be detected or mitigated. Presence of a surveillance mobile robot will be very useful for such a scenario. This project work is an effort towards the development of a mobile robot that can be used for remote surveillance. A four DOF (degree of freedom) articulated robotic arm, and mobile base is developed. Manipulator is designed using Autodesk inventor, and then fabricated in PIEAS Fabrication Shop. All joints of the manipulator are revolute joints. Maxon DC motors have been used to empower the joints with the help of gears. Spur gear and planetary gear head have been used to increase the torque at joints and to reduce the speed. The report provides complete detail about mechanical design, moreover some casting procedures are also discussed at the end to cast main parts of robot, problems that were faced during the project and their solutions are also discussed in the report. (author)

  20. Effects of high-energy proton irradiation on the density and Hall mobility of majority carriers in single crystalline n-type CuInSe2 thin films

    International Nuclear Information System (INIS)

    Proton irradiation effects in CuInSe2 (CIS) thin films have been investigated as a function of proton energy (0.38, 1 and 3 MeV). Single crystalline n-CIS thin films were prepared by radio frequency sputtering. The electrical properties of as-grown and irradiated samples were measured. The typical electron concentration and Hall mobility in as-grown samples were 4 x 1016 cm-3 and 120 cm2/Vs, respectively. After 0.38 and 1MeV proton irradiation, both of the electron concentration and Hall mobility were decreased as the fluence exceeded 1 x 1013 cm-2, but for 3 MeV proton irradiation, they were decreased over the fluence of 1 x 1014 cm-2. The damage by high-energy proton irradiation was lower than that by low-energy proton irradiation. The carrier removal rate with proton fluence was estimated about from 1800 to 300 cm-1as proton energy was changed from 0.38 to 3 MeV. (copyright 2003 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  1. Vacancy defect and carrier distributions in the high mobility electron gas formed at ion-irradiated SrTiO3 surfaces

    International Nuclear Information System (INIS)

    Using a combination of advanced characterization tools (positron annihilation spectroscopy, conductive-tip atomic force microscopy, and high-field magnetotransport), we have studied the extension, origin and properties of the high mobility electron gas (HMEG) generated by etching the SrTiO3 surfaces with Ar+ ions. Contrary to previous assumptions, we show that this HMEG is not confined to nanometric thickness but extends to a few micrometer from the surface. We discuss this unanticipated large spatial extension in terms of the striking large diffusion of oxygen vacancy-related defects.

  2. Influence of the carrier mobility distribution on the Hall and the Nernst effect measurements in n-type InSb

    International Nuclear Information System (INIS)

    In this study, we report magneto-resistance measurements on an n-doped InSb film, to separate the contributions of the electrical currents from the heat currents. We have demonstrated a prototype for a magnetic field sensor which is powered by heat currents and does not require any electrical current. We fabricated two Hall bars, where a low frequency (f = 0.05 Hz) AC current, was applied between the two contacts in one of the Hall bars. Separating the f and 2f components of the voltage measured across the second Hall bar was used to distinguish between the electrical and the heat contributions to the electron currents. Our observations can be modeled using a Gaussian distribution of mobility within the sample

  3. Influence of the carrier mobility distribution on the Hall and the Nernst effect measurements in n-type InSb

    Science.gov (United States)

    Madon, B.; Wegrowe, J.-E.; Drouhin, H.-J.; Liu, X.; Furdyna, J.; Khodaparast, G. A.

    2016-01-01

    In this study, we report magneto-resistance measurements on an n-doped InSb film, to separate the contributions of the electrical currents from the heat currents. We have demonstrated a prototype for a magnetic field sensor which is powered by heat currents and does not require any electrical current. We fabricated two Hall bars, where a low frequency (f = 0.05 Hz) AC current, was applied between the two contacts in one of the Hall bars. Separating the f and 2f components of the voltage measured across the second Hall bar was used to distinguish between the electrical and the heat contributions to the electron currents. Our observations can be modeled using a Gaussian distribution of mobility within the sample.

  4. Influence of the carrier mobility distribution on the Hall and the Nernst effect measurements in n-type InSb

    Energy Technology Data Exchange (ETDEWEB)

    Madon, B.; Wegrowe, J.-E.; Drouhin, H.-J. [Laboratoire des Solides Irradiés, CNRS UMR 7642, CEA-DSM-IRAMIS, Ecole polytechnique, Université Paris-Saclay, 91128 Palaiseau (France); Liu, X.; Furdyna, J. [Department of Physics, University of Notre Dame, Notre Dame, Indiana 46556 (United States); Khodaparast, G. A., E-mail: khoda@vt.edu [Department of Physics, Virginia Tech, Blacksburg, Virginia 24061 (United States)

    2016-01-14

    In this study, we report magneto-resistance measurements on an n-doped InSb film, to separate the contributions of the electrical currents from the heat currents. We have demonstrated a prototype for a magnetic field sensor which is powered by heat currents and does not require any electrical current. We fabricated two Hall bars, where a low frequency (f = 0.05 Hz) AC current, was applied between the two contacts in one of the Hall bars. Separating the f and 2f components of the voltage measured across the second Hall bar was used to distinguish between the electrical and the heat contributions to the electron currents. Our observations can be modeled using a Gaussian distribution of mobility within the sample.

  5. 基于热刺激电流的空间电介质载流子迁移率测量方法%CALCULATION OF CARRIER MOBILITY IN SPACE INSULATER BY THE THERMALLY STIMULATED CURRENT

    Institute of Scientific and Technical Information of China (English)

    李盛涛; 李巍巍; 闵道敏; 林敏; 黄印

    2012-01-01

    The charge transport properties of dielectrics determine spacecraft charging level and electrostatic discharging (ESD) probability, affecting the reliability and lifetime of spacecrafts. To investigate the charge carrier mobility of space grade polyimide at various temperatures, a novel method based on Thermally Stimulated Current (TSC) is proposed in present paper. Charges will inject from the electrodes into the material after a high voltage is applied for a while, and been maintained in the traps when the material is frozen with liquid Nitrogen. The trapped charges in the insulator are assumed to satisfy Boltzmann distribution. When the temperature of the sample is increased slowly, the trapped charges will gradually detrap to the conduction band and transport to the contacted electrode. Based on this physical model, we can derive the charge carrier mobility from TSC. We calculate the temperature dependent charge carrier mobility of polyimide film at the temperature range of 173 K ~493 K. These results are compared with that measured by space charge limited current method, and they are in good agreement with each other. It may provide an efficient way to study the charge transport characteristics of insulators and help spacecraft engineers better the design of spacecraft shielding.%为了研究空间用聚酰亚胺材料在不同温度下的载流子迁移率,提出了基于热刺激电流(TSC)测量载流子迁移率的模型.对试样施加一段时间的电压,会有电荷注入到材料中.当试样温度降低到液氮温度时,注入电荷被保持在材料的陷阱中.假设入陷的电荷服从玻尔兹曼分布,陷阱中电荷会随着材料温度的上升而出陷,然后在自建电场的作用下向电极传输.在这个物理模型的基础上,推导出了载流子迁移率的解析公式.通过计算,得到了聚酰亚胺在不同温度下的载流子迁移率.同时,采用空间电荷限制电流方法测量了聚酰亚胺

  6. 再谈地面数字电视单载波系统移动接收的实现%Further Discussion of Mobil Reception Implementation in Single Carrier Systems of Digital Terrestrial Television Transmission

    Institute of Scientific and Technical Information of China (English)

    徐孟侠

    2013-01-01

    作为《地面数字电视单载波系统如何实现移动接收》的续篇,在回顾典型案例及介绍地面数字电视单载波系统的新进展后,补充讨论接收端的一些时间域处理技术:1)从相位域和时间域分析主信号和单个“0 dB回波”的能量叠加后,C/N门限值可望下降约1.5~2.5 dB;2)对“同步码捕获/保持”采用“部分序列法”可缩短所需时间,作补充说明;3)对自适应信道均衡器的卷积运算则提出“6 msb(最高有效位)/符号处理法”替代原8比特/符号,以显著节省运算资源.%As the continuation of "How mobile digital television reception can be realized in single carrier systems", after reviewing its typical implementations and the recent progress of DTT single carrier systems, some time domain processing techniques in the receivers are discussed additionally: 1) the basic idea in phase and time domains, decreasing 1.5-2.5 dB in C/ N threshold value is discussed, by combining the energy of main signal and single "0 dB echo". 2) "partial sequence method" is explained additionally, to shorten the time needed for "capture/hold of synchronous code". 3) "6 msb processing/symbol", instead of 8 bits/symbol, is proposed for adaptive channel equalizer in the convolution, as to save the computing resources significantly.

  7. Operation of a resistive-gate MOS transmission line with time-varying gate voltages and field-dependent carrier mobility

    International Nuclear Information System (INIS)

    A computer analysis of the charge-transport process in an MOS transmission line (MOSTL) operating in deep depletion is presented. The mathematical model is developed taking into account time-dependent gate voltages, field-dependent surface mobility, and voltage-dependent depletion capacitance. A distributed equivalent circuit model is derived. The contributions of the physical transport mechanisms are investigated from the standpoint of assesing the influence of the design parameters and operating conditions on the performances of the structure. Several driving techniques which use time-varying gate voltages are proposed and simulated. Special emphasis is directed toward the possible improvements of the performances of an MOSTL used as a bit line in a continuously charge-coupled RAM or as a variable delay line for digital signals. To a certain extent, the theory derived in this paper is also valid for charge-transfer devices, in particular for the charge-transfer process in bucket-brigade devices and under the transfer gates of two-phase CCD's. (author)

  8. Preconception Carrier Screening

    Science.gov (United States)

    ... Events Advocacy For Patients About ACOG Preconception Carrier Screening Home For Patients Search FAQs Preconception Carrier Screening ... Screening FAQ179, August 2012 PDF Format Preconception Carrier Screening Pregnancy What is preconception carrier screening? What is ...

  9. What Is Carrier Screening?

    Science.gov (United States)

    ... you want to learn. Search form Search Carrier screening You are here Home Testing & Services Testing for ... help you make the decision. What Is Carrier Screening? Carrier screening checks if a person is a " ...

  10. High-mobility diamond

    Science.gov (United States)

    Landstrass, Maurice I.

    1994-04-01

    Recent improvements in the CVD diamond deposition process have made possible the fabrication of diamond photoconductive diodes with carrier mobility and lifetime exceeding the values typical of natural gemstones. One of the more surprising recent results is that the best room-temperature carrier properties have been measured on polycrystalline diamond films. The combined electron- hole mobility, as measured by transient photoconductivity at low carrier densities, is 4000 square centimeters per volt per second at electric field of 200 volts per centimeter and is comparable to that of the best single-crystal IIa natural diamonds. Carrier lifetimes measured under the same conditions are 150 picoseconds for the CVD diamond films. The collection distance within the diamond films, at the highest applied fields, is comparable to the average film grain size, indicative of little or no carrier scattering at grain boundaries. A comparison of SIMS measurements with electrical results suggest that impurity incorporation in the near grain boundary regions are responsible for controlling the carrier mobility.

  11. Wafer-scale characterization of carrier dynamics in graphene

    DEFF Research Database (Denmark)

    Buron, Jonas Christian Due; Petersen, Dirch Hjorth; Bøggild, Peter;

    2015-01-01

    The electronic properties of single-layer graphene, such as surface conductance, carrier concentration, scattering time and mobility, can be characterized in a noncontact manner by THz time-domain spectroscopy. Standard spectroscopic imaging reveals the AC conductance over large areas with a few...... hundred μm resolution, and spectroscopic imaging on back-gated graphene allows for extraction of both the carrier concentration and the mobility. We find that spatial variations of the conductance of single-layer CVD-grown graphene are predominantly due to variations in mobility rather than in carrier...

  12. Staging Mobilities / Designing Mobilities

    DEFF Research Database (Denmark)

    Jensen, Ole B.

    2015-01-01

    people are ‘staging themselves’ (from below). Staging mobilities is a dynamic process between ‘being staged’ (for example, being stopped at traffic lights) and the ‘mobile staging’ of interacting individuals (negotiating a passage on the pavement). Staging mobilities is about the fact that mobility is...

  13. Exploring carrier transport phenomena in a CVD-assembled graphene FET on hexagonal boron nitride

    International Nuclear Information System (INIS)

    The supporting substrate plays a crucial role in preserving the superb electrical characteristics of an atomically thin 2D carbon system. We explore carrier transport behavior in a chemical-vapor-deposition- (CVD-) assembled graphene monolayer on hexagonal boron nitride (h-BN) substrate. Graphene-channel field-effect transistors (GFETs) were fabricated on ultra-thin h-BN multilayers to screen out carrier scattering from the underlying SiO2 substrate. To explore the transport phenomena, we use three different approaches to extract carrier mobility, namely, effective carrier mobility (μeff), intrinsic carrier mobility (μ), and field-effect mobility (μFE). A comparative study has been conducted based on the electrical characterization results, uncovering the impacts of supporting substrate material and device geometry scaling on carrier mobility in GFETs with CVD-assembled graphene as the active channel. (paper)

  14. Coexistence of Dirac and massive carriers in α-(BEDT-TTF){sub 2}I{sub 3} under hydrostatic pressure

    Energy Technology Data Exchange (ETDEWEB)

    Navarin, Fabien; Tisserond, Emilie [Laboratoire de Physique des Solides, UMR 8502, CNRS-Université Paris-Sud, Orsay F-91405 (France); Auban-Senzier, Pascale, E-mail: pascale.senzier@u-psud.fr [Laboratoire de Physique des Solides, UMR 8502, CNRS-Université Paris-Sud, Orsay F-91405 (France); Mézière, Cécile; Batail, Patrick [MOLTECH-Anjou, UMR 6200, CNRS-Université d' Angers, Bat. K, Angers F-49045 (France); Pasquier, Claude; Monteverde, Miguel [Laboratoire de Physique des Solides, UMR 8502, CNRS-Université Paris-Sud, Orsay F-91405 (France)

    2015-03-01

    We present magnetotransport measurements of α-(BEDT-TTF){sub 2}I{sub 3} crystals under hydrostatic pressure larger than 1.5 GPa where Dirac carriers are present. We show not only the existence of high-mobility Dirac carriers but we also prove experimentally the presence of low-mobility massive carriers, in agreement with band-structure calculations.

  15. Graphene mobility mapping

    DEFF Research Database (Denmark)

    Buron, Jonas Christian Due; Pizzocchero, Filippo; Jepsen, Peter Uhd;

    2015-01-01

    Carrier mobility and chemical doping level are essential figures of merit for graphene, and large-scale characterization of these properties and their uniformity is a prerequisite for commercialization of graphene for electronics and electrodes. However, existing mapping techniques cannot directly...... assess these vital parameters in a non-destructive way. By deconvoluting carrier mobility and density from non-contact terahertz spectroscopic measurements of conductance in graphene samples with terahertz-transparent backgates, we are able to present maps of the spatial variation of both quantities over...... graphene indicates dominance by charged scatterers. Unexpectedly, significant variations in mobility rather than doping are the cause of large conductance inhomogeneities, highlighting the importance of statistical approaches when assessing large-area graphene transport properties....

  16. Effect of doping concentration and disorder on the mobility of carriers in organic light emitting diodes%掺杂浓度和无序对柔性有机发光二极管载流子迁移率的影响

    Institute of Scientific and Technical Information of China (English)

    陈雨璐; 侯晓远; 岑剡

    2011-01-01

    基于电荷分布的泊松方程和载流子输运方程,考虑最低能量非占据态和最高能量占据态的载流子态密度服从双高斯分布的模型,自洽地研究了掺杂浓度和无序对Alq3柔性有机发光二极管载流子迁移率的影响.发现掺杂浓度低于1×1020cm-3时,掺杂浓度对迁移率影响很小,迁移率几乎保持不变;当掺杂浓度大于1×1020cm-3时,载流子迁移率非线性增加,与实验结果很好一致.考虑不同无序度时,发现无序度的增加,相应的迁移率下降;低掺杂浓度下迁移率与无序度的大小关系不大,当掺杂浓度较高的时,无序度较小的材料迁移率增加较快.最终给出了柔性发光二极管器件的发光功率密度与电压关系,表明载流子浓度和无序相关的迁移率结果对制备高性能的柔性有机发光二极管具有指导意义.%Based on the Poisson' s equation of charge distribution and the transport equation of carriers, the effect of doping concentration and disordered degree on the mobility of carriers in the Alq3 flexible organic light-emitting diodes has been studied self-consistently.The density of states of the carriers was described with the double Gaussian distributions because of the energy disorders of organic molecules.It was found that the carrers'mobility is almost fixed with doping concentration smaller than 1 × 1020cm-3.The carriers'mobility increased nonlinearly when the doping concentration was larger than 1 ×1020cm-3, in well agreement with the experimental results.It was also showed that the increase of mobility as a function of doping concentration for smaller disordered degree is faster than that for larger disordered one.With low doping concentration, the disordered degree has little effect on the mobility.Finally,the doping concentration and the disorder degree dependence of the mobility is used to simulate the variations of the luminescence power density of the device with the voltage bias.It was

  17. Hall mobility in multicrystalline silicon

    Science.gov (United States)

    Schindler, F.; Geilker, J.; Kwapil, W.; Warta, W.; Schubert, M. C.

    2011-08-01

    Knowledge of the carrier mobility in silicon is of utmost importance for photovoltaic applications, as it directly influences the diffusion length and thereby the cell efficiency. Moreover, its value is needed for a correct quantitative evaluation of a variety of lifetime measurements. However, models that describe the carrier mobility in silicon are based on theoretical calculations or fits to experimental data in monocrystalline silicon. Multicrystalline (mc) silicon features crystal defects such as dislocations and grain boundaries, with the latter possibly leading to potential barriers through the trapping of charge carriers and thereby influencing the mobility, as shown, for example, by Maruska et al. [Appl. Phys. Lett. 36, 381 (1980)]. To quantify the mobilities in multicrystalline silicon, we performed Hall measurements in p-type mc-Si samples of various resistivities and different crystal structures and compared the data to majority carrier Hall mobilities in p-type monocrystalline floatzone (FZ) silicon. For lack of a model that provides reliable values of the Hall mobility in silicon, an empirical fit similar to existing models for conductivity mobilities is proposed based on Hall measurements of monocrystalline p-type FZ silicon. By comparing the measured Hall mobilities obtained from mc silicon with the corresponding Hall mobilities in monocrystalline silicon of the same resistivity, we found that the mobility reduction due to the presence of crystal defects in mc-Si ranges between 0% and 5% only. Mobility decreases of up to 30% as reported by Peter et al. [Proceedings of the 23rd European Photovoltaic Solar Energy Conference, Valencia, Spain, 1-5 September 2008], or even of a factor of 2 to 3 as detected by Palais et al. [Mater. Sci. Eng. B 102, 184 (2003)], in multicrystalline silicon were not observed.

  18. Charge carrier transport in liquid crystals

    International Nuclear Information System (INIS)

    The materials exhibiting charge carrier mobility ranging from 10−3 to 0.1 cm2/Vs, i.e., between those of amorphous and crystalline materials, had been missing before the 1990s when the electronic conduction in liquid crystals was discovered. Since then, various liquid crystalline materials including discotic and calamitic liquid crystals have been studied in order to clarify their charge carrier transport properties in liquid crystalline mesophases. In this article, the historical background of the discovery of electronic conduction in liquid crystals, intrinsic and extrinsic conductions, unique properties of the charge carrier transport, the effect of molecular alignment on it, and the conduction mechanism in liquid crystalline mesophases are shortly described on the basis of the experimental and theoretical studies accumulated in these two decades, noting that the missing materials were liquid crystals. - Highlights: • Liquid crystals exhibit charge mobility ranging from 10–3 to 0.1 cm2/Vs. • Electronic (intrinsic) and ionic (extrinsic) conductions in liquid crystals • Unique charge carrier transport properties in liquid crystals • Effect of molecular alignment in mesophases on charge carrier transport • Conduction mechanism in smectic liquid crystals

  19. Charge carrier coherence and Hall effect in organic semiconductors.

    Science.gov (United States)

    Yi, H T; Gartstein, Y N; Podzorov, V

    2016-01-01

    Hall effect measurements are important for elucidating the fundamental charge transport mechanisms and intrinsic mobility in organic semiconductors. However, Hall effect studies frequently reveal an unconventional behavior that cannot be readily explained with the simple band-semiconductor Hall effect model. Here, we develop an analytical model of Hall effect in organic field-effect transistors in a regime of coexisting band and hopping carriers. The model, which is supported by the experiments, is based on a partial Hall voltage compensation effect, occurring because hopping carriers respond to the transverse Hall electric field and drift in the direction opposite to the Lorentz force acting on band carriers. We show that this can lead in particular to an underdeveloped Hall effect observed in organic semiconductors with substantial off-diagonal thermal disorder. Our model captures the main features of Hall effect in a variety of organic semiconductors and provides an analytical description of Hall mobility, carrier density and carrier coherence factor. PMID:27025354

  20. Charge carrier coherence and Hall effect in organic semiconductors

    Science.gov (United States)

    Yi, H. T.; Gartstein, Y. N.; Podzorov, V.

    2016-03-01

    Hall effect measurements are important for elucidating the fundamental charge transport mechanisms and intrinsic mobility in organic semiconductors. However, Hall effect studies frequently reveal an unconventional behavior that cannot be readily explained with the simple band-semiconductor Hall effect model. Here, we develop an analytical model of Hall effect in organic field-effect transistors in a regime of coexisting band and hopping carriers. The model, which is supported by the experiments, is based on a partial Hall voltage compensation effect, occurring because hopping carriers respond to the transverse Hall electric field and drift in the direction opposite to the Lorentz force acting on band carriers. We show that this can lead in particular to an underdeveloped Hall effect observed in organic semiconductors with substantial off-diagonal thermal disorder. Our model captures the main features of Hall effect in a variety of organic semiconductors and provides an analytical description of Hall mobility, carrier density and carrier coherence factor.

  1. Features of charge carrier transport determined from carrier extraction current in .mu.c-Si:H

    Czech Academy of Sciences Publication Activity Database

    Juška, G.; Arlauskas, K.; Nekrašas, N.; Stuchlík, Jiří; Niquille, X.; Wyrsch, N.

    299-302, - (2002), s. 375-379. ISSN 0022-3093 Grant ostatní: VMSF(LT) 01SP-02 Institutional research plan: CEZ:AV0Z1010914 Keywords : mobility of majority carriers * photoconductivity transport Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.435, year: 2002

  2. Clustering Optimisation Techniques in Mobile Networks

    OpenAIRE

    Rozaki, Eleni

    2016-01-01

    The use of mobile phones has exploded over the past years,abundantly through the introduction of smartphones and the rapidly expanding use of mobile data. This has resulted in a spiraling problem of ensuring quality of service for users of mobile networks. Hence, mobile carriers and service providers need to determine how to prioritise expansion decisions and optimise network faults to ensure customer satisfaction and optimal network performance. To assist in that decision-making process, thi...

  3. Peptide-Carrier Conjugation

    DEFF Research Database (Denmark)

    Hansen, Paul Robert

    To produce antibodies against synthetic peptides it is necessary to couple them to a protein carrier. This chapter provides a nonspecialist overview of peptide-carrier conjugation. Furthermore, a protocol for coupling cysteine-containing peptides to bovine serum albumin is outlined.......To produce antibodies against synthetic peptides it is necessary to couple them to a protein carrier. This chapter provides a nonspecialist overview of peptide-carrier conjugation. Furthermore, a protocol for coupling cysteine-containing peptides to bovine serum albumin is outlined....

  4. High Charge-Carrier Mobility of 2.5 cm(2) V(-1) s(-1) from a Water-Borne Colloid of a Polymeric Semiconductor via Smart Surfactant Engineering.

    Science.gov (United States)

    Cho, Jangwhan; Cheon, Kwang Hee; Ahn, Hyungju; Park, Kwang Hun; Kwon, Soon-Ki; Kim, Yun-Hi; Chung, Dae Sung

    2015-10-01

    Semiconducting polymer nanoparticles dispersed in water are synthesized by a novel method utilizing non-ionic surfactants. By developing a smart surfactant engineering technique involving a selective post-removal process of surfactants, an unprecedentedly high mobility of 2.51 cm(2) V(-1) s(-1) from a water-borne colloid is demonstrated for the first time. PMID:26288123

  5. Asymmetric Carrier Random PWM

    DEFF Research Database (Denmark)

    Mathe, Laszlo; Lungeanu, Florin; Rasmussen, Peter Omand;

    2010-01-01

    This paper presents a new fixed carrier frequency random PWM method, where a new type of carrier wave is proposed for modulation. Based on the measurements, it is shown that the spread effect of the discrete components from the motor current spectra is very effective independent of the modulation...

  6. Performance Analysis of MC-CDMA in the Presence of Carriers Phase Errors

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    This paper presents the effect of carriers phase error on MC-CDMA performance in downlink mobile communications. Signal-to-Noise Ratio (SNR) and Bit-Error-Rate (BER) are analyzed taking into account the effect of carrier phase errors. It is shown that the MC-CDMA system is very sensitive to a carrier frequency offset, the system performance rapidly degrades and strongly depends on the number of carriers. For a maximal load, the degradation caused by carrier phase jitter is independent of the number of the carriers.

  7. High mobility emissive organic semiconductor

    Science.gov (United States)

    Liu, Jie; Zhang, Hantang; Dong, Huanli; Meng, Lingqiang; Jiang, Longfeng; Jiang, Lang; Wang, Ying; Yu, Junsheng; Sun, Yanming; Hu, Wenping; Heeger, Alan J.

    2015-12-01

    The integration of high charge carrier mobility and high luminescence in an organic semiconductor is challenging. However, there is need of such materials for organic light-emitting transistors and organic electrically pumped lasers. Here we show a novel organic semiconductor, 2,6-diphenylanthracene (DPA), which exhibits not only high emission with single crystal absolute florescence quantum yield of 41.2% but also high charge carrier mobility with single crystal mobility of 34 cm2 V-1 s-1. Organic light-emitting diodes (OLEDs) based on DPA give pure blue emission with brightness up to 6,627 cd m-2 and turn-on voltage of 2.8 V. 2,6-Diphenylanthracene OLED arrays are successfully driven by DPA field-effect transistor arrays, demonstrating that DPA is a high mobility emissive organic semiconductor with potential in organic optoelectronics.

  8. Trustworthy execution on mobile devices

    CERN Document Server

    Vasudevan, Amit; Newsome, James

    2013-01-01

    This brief considers the various stakeholders in today's mobile device ecosystem, and analyzes why widely-deployed hardware security primitives on mobile device platforms are inaccessible to application developers and end-users. Existing proposals are also evaluated for leveraging such primitives, and proves that they can indeed strengthen the security properties available to applications and users, without reducing the properties currently enjoyed by OEMs and network carriers. Finally, this brief makes recommendations for future research that may yield practical and deployable results.

  9. Mobile Learning Using Mobile Phones

    Science.gov (United States)

    Vicente, Paula

    2013-01-01

    The participation in mobile learning programs is conditioned by having/using mobile communication technology. Those who do not have or use such technology cannot participate in mobile learning programs. This study evaluates who are the most likely participants of mobile learning programs by examining the demographic profile and mobile phone usage…

  10. Mobile Lexicography

    DEFF Research Database (Denmark)

    Køhler Simonsen, Henrik

    2015-01-01

    Mobile phones are ubiquitous and have completely transformed the way we live, work, learn and conduct our everyday activities. Mobile phones have also changed the way users access lexicographic data. In fact, it can be argued that mobile phones and lexicography are not yet compatible. Modern users...... are already mobile – but lexicography is not yet fully ready for the mobile challenge, mobile users and mobile user situations. The article is based on empirical data from two surveys comprising 10 medical doctors, who were asked to look up five medical substances with the medical dictionary app...... mobile lexicography....

  11. Imaging ballistic carrier trajectories in graphene using scanning gate microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Morikawa, Sei; Masubuchi, Satoru [Institute of Industrial Science, University of Tokyo, 4-6-1 Komaba, Meguro, Tokyo 153-8505 (Japan); Dou, Ziwei; Wang, Shu-Wei; Smith, Charles G.; Connolly, Malcolm R., E-mail: mrc61@cam.ac.uk [Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge CB3 0HE (United Kingdom); Watanabe, Kenji; Taniguchi, Takashi [National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044 (Japan); Machida, Tomoki, E-mail: tmachida@iis.u-tokyo.ac.jp [Institute of Industrial Science, University of Tokyo, 4-6-1 Komaba, Meguro, Tokyo 153-8505 (Japan); Institute for Nano Quantum Information Electronics, University of Tokyo, 4-6-1 Komaba, Meguro, Tokyo 153-8505 (Japan)

    2015-12-14

    We use scanning gate microscopy to map out the trajectories of ballistic carriers in high-mobility graphene encapsulated by hexagonal boron nitride and subject to a weak magnetic field. We employ a magnetic focusing geometry to image carriers that emerge ballistically from an injector, follow a cyclotron path due to the Lorentz force from an applied magnetic field, and land on an adjacent collector probe. The local electric field generated by the scanning tip in the vicinity of the carriers deflects their trajectories, modifying the proportion of carriers focused into the collector. By measuring the voltage at the collector while scanning the tip, we are able to obtain images with arcs that are consistent with the expected cyclotron motion. We also demonstrate that the tip can be used to redirect misaligned carriers back to the collector.

  12. A MOBILITY MODEL FOR MOSFET DEVICE DIMULATION

    OpenAIRE

    Walker, A.; Woerlee, P.

    1988-01-01

    The device characteristics of sub-micron MOS transistors depend strongly on the mobility of the charge carriers in the inversion layer. A new low lateral field mobility model for the normal field dependence will be presented. Good agreement was found between the predicted and measured mobilities for a large variety of samples. The model was successfully incorporated into a two - dimensional device simulation program which gave predictions agreeing well with experimental data.

  13. Comparison of mobility extraction methods based on field-effect measurements for graphene

    Directory of Open Access Journals (Sweden)

    Hua Zhong

    2015-05-01

    Full Text Available Carrier mobility extraction methods for graphene based on field-effect measurements are explored and compared according to theoretical analysis and experimental results. A group of graphene devices with different channel lengths were fabricated and measured, and carrier mobility is extracted from those electrical transfer curves using three different methods. Accuracy and applicability of those methods were compared. Transfer length method (TLM can obtain accurate density dependent mobility and contact resistance at relative high carrier density based on data from a group of devices, and then can act as a standard method to verify other methods. As two of the most popular methods, direct transconductance method (DTM and fitting method (FTM can extract mobility easily based on transfer curve of a sole graphene device. DTM offers an underestimated mobility at any carrier density owing to the neglect of contact resistances, and the accuracy can be improved through fabricating field-effect transistors with long channel and good contacts. FTM assumes a constant mobility independent on carrier density, and then can obtain mobility, contact resistance and residual density stimulations through fitting a transfer curve. However, FTM tends to obtain a mobility value near Dirac point and then overestimates carrier mobility of graphene. Comparing with the DTM and FTM, TLM could offer a much more accurate and carrier density dependent mobility, that reflects the complete properties of graphene carrier mobility.

  14. Carrier Load Balancing and Packet Scheduling for Multi-Carrier Systems

    DEFF Research Database (Denmark)

    Wang, Yuanye; Pedersen, Klaus; Sørensen, Troels Bundgaard;

    2010-01-01

    Abstract-In this paper we focus on resource allocation for next generation wireless communication systems with aggregation of multiple Component Carriers (CCs), i.e., how to assign the CCs to each user, and how to multiplex multiple users in each CC. We first investigate two carrier load balancing...... methods for allocating the CCs to the users- Round Robin (RR) and Mobile Hashing (MH) balancing by means of a simple theoretical formulation, as well as system level simulations. At Layer-2 we propose a simple cross-CC packet scheduling algorithm that improves the coverage performance and the resource...... allocation fairness among users, as compared to independent scheduling per CC. The Long Term Evolution (LTE)-Advanced is selected for the case study of a multi-carrier system. In such a system, RR provides better performance than MH balancing, and the proposed simple scheduling algorithm is shown to be...

  15. Carrier Transport Mechanism in Single Crystalline Organic Semiconductor Thin Film Elucidated by Visualized Carrier Motion.

    Science.gov (United States)

    Matsubara, Kohei; Abe, Kentaro; Manaka, Takaaki; Iwamoto, Mitsumasa

    2016-04-01

    Time-resolved microscopic second harmonic generation (TRM-SHG) measurement was conducted to evaluate temperature dependence of the anisotropic carrier transport process in 6,13-Bis(triisopropylsilylethynyl) (TIPS) pentacene single crystalline domains for two orthogonal directions. Enhancement of the electric field induced SHG (EFI-SHG) signal at the electrode edge at low temperature suggests the presence of potential drop in the injection process. We directly evaluated temperature dependence of the carrier mobility by taking into account the potential drop, and concluded that the Marcus theory is appropriate to interpret the carrier transport in anisotropic TIPS pentacene thin film. TRM-SHG method is a facile and effective way to directly visualize transport process in anisotropic materials and to evaluate injection and transport processes simultaneously. PMID:27451638

  16. Duchenne muscular dystrophy carriers

    International Nuclear Information System (INIS)

    By means of magnetic resonance imaging (MRI), the proton spin-lattice relaxation times (T1 values) of the skeletal muscles were measured in Duchenne muscular dystrophy (DMD) carriers and normal controls. The bound water fraction (BWF) was calculated from the T1 values obtained, according to the fast proton diffusion model. In the DMD carriers, T1 values of the gluteus maximus and quadriceps femoris muscles were significantly higher, and BWFs of these muscles were significantly lower than in normal control. Degenerative muscular changes accompanied by interstitial edema were presumed responsible for this abnormality. No correlation was observed between the muscle T1 and serum creatine kinase values. The present study showed that MRI could be a useful method for studying the dynamic state of water in both normal and pathological skeletal muscles. Its possible utility for DMD carrier detection was discussed briefly. (orig.)

  17. Mobile Probes in Mobile Learning

    OpenAIRE

    Ørngreen, Rikke; Blomhøj, Ulla; Duvaa, Uffe

    2011-01-01

    In this paper experiences from using mobile probes in educational design of a mobile learning application is presented. The probing process stems from the cultural probe method, and was influenced by qualitative interview and inquiry approaches. In the project, the mobile phone was not only acting as an agent for acquiring empirical data (as the situation in hitherto mobile probe settings) but was also the technological medium for which data should say something about (mobile learning). Conse...

  18. Photo-generated carriers lose energy during extraction from polymer-fullerene solar cells

    KAUST Repository

    Melianas, Armantas

    2015-11-05

    In photovoltaic devices, the photo-generated charge carriers are typically assumed to be in thermal equilibrium with the lattice. In conventional materials, this assumption is experimentally justified as carrier thermalization completes before any significant carrier transport has occurred. Here, we demonstrate by unifying time-resolved optical and electrical experiments and Monte Carlo simulations over an exceptionally wide dynamic range that in the case of organic photovoltaic devices, this assumption is invalid. As the photo-generated carriers are transported to the electrodes, a substantial amount of their energy is lost by continuous thermalization in the disorder broadened density of states. Since thermalization occurs downward in energy, carrier motion is boosted by this process, leading to a time-dependent carrier mobility as confirmed by direct experiments. We identify the time and distance scales relevant for carrier extraction and show that the photo-generated carriers are extracted from the operating device before reaching thermal equilibrium.

  19. Addressing Carrier Aggregation with Narrow-band Tunable Antennas

    DEFF Research Database (Denmark)

    Barrio, Samantha Caporal Del; Morris, Art; Pedersen, Gert F.

    2016-01-01

    Enhancing the operating bandwidth of antennas is particularly challenging when the antenna is confined in a very restricted volume, as is the case for mobile phones. However, increasing the bandwidth provides higher data rates to the users. Consequently, the carrier aggregation technology has bee...

  20. Intestinal solute carriers

    DEFF Research Database (Denmark)

    Steffansen, Bente; Nielsen, Carsten Uhd; Brodin, Birger; Eriksson, André Huss; Andersen, Rikke; Frokjaer, Sven

    2004-01-01

    A large amount of absorptive intestinal membrane transporters play an important part in absorption and distribution of several nutrients, drugs and prodrugs. The present paper gives a general overview on intestinal solute carriers as well as on trends and strategies for targeting drugs and...

  1. Glycosylation of solute carriers

    DEFF Research Database (Denmark)

    Pedersen, Nis Borbye; Carlsson, Michael C; Pedersen, Stine Helene Falsig

    2016-01-01

    Solute carriers (SLCs) are one of the largest groups of multi-spanning membrane proteins in mammals and include ubiquitously expressed proteins as well as proteins with highly restricted tissue expression. A vast number of studies have addressed the function and organization of SLCs as well as...

  2. Information and Its Carriers.

    Science.gov (United States)

    Herrmann, F.; And Others

    1985-01-01

    Describes: (1) the structure of a data transmission source, carrier, and receiver; (2) a quantitative measure for the amount of data, followed by some quantitative examples of data transmission processes; (3) the concept of data current; (4) data containers; and (5) how this information can be used to structure physics courses. (JN)

  3. Mobile payment

    CERN Document Server

    Lerner, Thomas

    2013-01-01

    Paying with mobile devices such as mobile phones or smart phones will expand worldwide in the coming years. This development provides opportunities for various industries (banking, telecommunications, credit card business, manufacturers, suppliers, retail) and for consumers.

  4. Mobile marketing

    OpenAIRE

    Švarc, Ondřej

    2010-01-01

    The goal of bachelor's thesis on the theme "Mobile marketing" is to outline its development and why is this new phenomen so important for all modern companies around the world. The work is not about simple description of mobile marketing media but it vividly informs about the latest trends and news from the world of mobile apps and games. It presents the most successful mobile apps which registered more than billion downloads and from their unique characteristics it unveils great potential of...

  5. Mobile marketing

    OpenAIRE

    KLEČKOVÁ, Zuzana

    2013-01-01

    The main aim of this thesis was to provide a comprehensive overview of the mobile marketing and analyze selected campaigns of Czech mobile marketing in comparison to world successful campaigns. The research contained studying of available literature about the theme to gain general knowledge about the issue. The theoretical part of the thesis contains predominantly various definitions of mobile marketing and its tools, advantages of these tools and some information about Mobile Marketing Assoc...

  6. Staging Mobilities

    DEFF Research Database (Denmark)

    Jensen, Ole B.

    lived as people are “staging themselves” (from below). Staging mobilities is a dynamic process between “being staged” (for example, being stopped at traffic lights) and the “mobile staging” of interacting individuals (negotiating a passage on the pavement). Staging Mobilities is about the fact that...

  7. Mobile Probes in Mobile Learning

    DEFF Research Database (Denmark)

    Ørngreen, Rikke; Blomhøj, Ulla; Duvaa, Uffe

    In this paper experiences from using mobile probes in educational design of a mobile learning application is presented. The probing process stems from the cultural probe method, and was influenced by qualitative interview and inquiry approaches. In the project, the mobile phone was not only acting...... as an agent for acquiring empirical data (as the situation in hitherto mobile probe settings) but was also the technological medium for which data should say something about (mobile learning). Consequently, not only the content of the data but also the ways in which data was delivered and handled......, provided a valuable dimension for investigating mobile use. The data was collected at the same time as design activities took place and the collective data was analysed based on user experience goals and cognitive processes from interaction design and mobile learning. The mobile probe increased the...

  8. Study of Charge Carrier Transport in GaN Sensors

    Directory of Open Access Journals (Sweden)

    Eugenijus Gaubas

    2016-04-01

    Full Text Available Capacitor and Schottky diode sensors were fabricated on GaN material grown by hydride vapor phase epitaxy and metal-organic chemical vapor deposition techniques using plasma etching and metal deposition. The operational characteristics of these devices have been investigated by profiling current transients and by comparing the experimental regimes of the perpendicular and parallel injection of excess carrier domains. Profiling of the carrier injection location allows for the separation of the bipolar and the monopolar charge drift components. Carrier mobility values attributed to the hydride vapor phase epitaxy (HVPE GaN material have been estimated as μe = 1000 ± 200 cm2/Vs for electrons, and μh = 400 ± 80 cm2/Vs for holes, respectively. Current transients under injection of the localized and bulk packets of excess carriers have been examined in order to determine the surface charge formation and polarization effects.

  9. Hungarian students’ carrier aspirations

    Directory of Open Access Journals (Sweden)

    A.S. Gubik

    2014-06-01

    Full Text Available The article analyzes the students’ carrier aspiration, right after their graduation and five years after their studies. It examines the differences arising from the students’ family business background and their most important social variables (gender, age. Then the study highlights the effects of study field on the students’ intention. The direct effect of education on starting an enterprise is undiscovered in the literature, the paper deals with the influence of availability and services use, offered by higher institutions.

  10. Comparison of human solute carriers

    OpenAIRE

    Schlessinger, Avner; Matsson, Pär; Shima, James E.; Pieper, Ursula; Yee, Sook Wah; Kelly, Libusha; Apeltsin, Leonard; Stroud, Robert M.; Ferrin, Thomas E; Giacomini, Kathleen M.; Sali, Andrej

    2010-01-01

    Solute carriers are eukaryotic membrane proteins that control the uptake and efflux of solutes, including essential cellular compounds, environmental toxins, and therapeutic drugs. Solute carriers can share similar structural features despite weak sequence similarities. Identification of sequence relationships among solute carriers is needed to enhance our ability to model individual carriers and to elucidate the molecular mechanisms of their substrate specificity and transport. Here, we desc...

  11. Recombination in liquid filled ionisation chambers with multiple charge carrier species: Theoretical and numerical results

    International Nuclear Information System (INIS)

    Liquid-filled ionisation chambers (LICs) are used in radiotherapy for dosimetry and quality assurance. Volume recombination can be quite important in LICs for moderate dose rates, causing non-linearities in the dose rate response of these detectors, and needs to be corrected for. This effect is usually described with Greening and Boag models for continuous and pulsed radiation respectively. Such models assume that the charge is carried by two different species, positive and negative ions, each of those species with a given mobility. However, LICs operating in non-ultrapure mode can contain different types of electronegative impurities with different mobilities, thus increasing the number of different charge carriers. If this is the case, Greening and Boag models can be no longer valid and need to be reformulated. In this work we present a theoretical and numerical study of volume recombination in parallel-plate LICs with multiple charge carrier species, extending Boag and Greening models. Results from a recent publication that reported three different mobilities in an isooctane-filled LIC have been used to study the effect of extra carrier species on recombination. We have found that in pulsed beams the inclusion of extra mobilities does not affect volume recombination much, a behaviour that was expected because Boag formula for charge collection efficiency does not depend on the mobilities of the charge carriers if the Debye relationship between mobilities and recombination constant holds. This is not the case in continuous radiation, where the presence of extra charge carrier species significantly affects the amount of volume recombination. - Highlights: • Analytical extension of Greening and Boag theories to multiple charge carriers. • Detailed numerical study of process of volume recombination in LICs. • Recombination in pulsed beams is independent of number and mobilities of carriers. • Multiple charge carriers have a significant effect in continuous

  12. Carrier transport uphill. I. General

    DEFF Research Database (Denmark)

    Rosenberg, T; Wilbrandt, W

    1963-01-01

    A quantitative treatment of a carrier pump operating with two carrier forms C and Z is presented. Asymmetric metabolic reactions are assumed to transform Z into C on one and C into Z on the other side of the membrane, establishing a carrier cycle. The kinetical consequences of this mechanism are...

  13. An Efficient Inter Carrier Interference Cancellation Schemes for OFDM Systems

    Directory of Open Access Journals (Sweden)

    B. Sathish Kumar

    2009-12-01

    Full Text Available Orthogonal Frequency Division Multiplexing (OFDM has recently been used widely in wireless communication systems. OFDM is very effective in combating inter-symbol interference and can achieve high data rate in frequency selective channel. For OFDM communication systems, the frequency offsets in mobile radio channels distort the orthogonality between subcarriers resulting in Inter Carrier Interference (ICI. ICI causes power leakage among subcarriers thus degrading the system performance. A well-known problem of OFDM is its sensitivity to frequency offset between the transmitted and received carrier frequencies. There are two deleterious effects caused by frequency offset one is the reduction of signal amplitude in the output of the filters matched to each of the carriers and the second is introduction of ICI from the other carriers. This research work investigates three effective methods for combating the effects of ICI: ICI Self Cancellation (SC, Maximum Likelihood (ML estimation, and Extended Kalman Filter (EKF method. These three methods are compared in terms of bit error rate performance and bandwidth efficiency. Through simulations, it is shown that the three techniques are effective in mitigating the modulation schemes, the ML and EKF methods perform better than the SC method.Keywords- Orthogonal frequency Division Multiplexing (OFDM; Inter Carrier Interference(ICI; Carrier to Interference Power Ratio (CIR;Self Cancellation(SC;Carrier Frequency Offset (CFO; Maximum Likelihood(ML; Extended Kalman Filtering(EKF.

  14. Maintainable substrate carrier for electroplating

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Chen-An; Abas, Emmanuel Chua; Divino, Edmundo Anida; Ermita, Jake Randal G.; Capulong, Jose Francisco S.; Castillo, Arnold Villamor; Ma, Diana Xiaobing

    2016-08-02

    One embodiment relates to a substrate carrier for use in electroplating a plurality of substrates. The carrier includes a non-conductive carrier body on which the substrates are placed and conductive lines embedded within the carrier body. A plurality of conductive clip attachment parts are attached in a permanent manner to the conductive lines embedded within the carrier body. A plurality of contact clips are attached in a removable manner to the clip attachment parts. The contact clips hold the substrates in place and conductively connecting the substrates with the conductive lines. Other embodiments, aspects and features are also disclosed.

  15. Mobility Work

    DEFF Research Database (Denmark)

    Bardram, Jakob Eyvind; Bossen, Claus

    2005-01-01

    coordination necessary in cooperative work, but focuses, we argue, mainly on the temporal aspects of cooperative work. As a supplement, the concept of mobility work focuses on the spatial aspects of cooperative work. Whereas actors seek to diminish the amount of articulation work needed in collaboration by......We posit the concept of Mobility Work to describe efforts of moving about people and things as part of accomplishing tasks. Mobility work can be seen as a spatial parallel to the concept of articulation work proposed by the sociologist Anselm Strauss. Articulation work describes efforts of...... constructing Standard Operation Procedures (SOPs), actors minimise mobility work by constructing Standard Operation Configurations (SOCs). We apply the concept of mobility work to the ethnography of hospital work, and argue that mobility arises because of the need to get access to people, places, knowledge and...

  16. Mobile Semiotics

    DEFF Research Database (Denmark)

    Jensen, Ole B.

    2013-01-01

    This chapter aims to understand the mobile condition of contemporary life with a particular view to the signifying dimension of the environment and its ‘readability’. The chapter explores the potentials of semiotics and its relationship to the new mobilities literature. What takes place is a...... ‘mobile sense making’ where signs and materially situated meanings connect to the moving human body and thus create particular challenges and complexities of making sense of the world. The chapter includes notions of mobility systems and socio-technical networks in order to show how a ‘semiotic layer’ may...

  17. Mobil marketing

    OpenAIRE

    Engelová, Kateřina

    2006-01-01

    Mobil marketing - reklama a podpora prodeje prostřednictvím mobilních telefonů. Technologické a kulturní předpoklady vzniku tohoto odvětví. Mobil marketing a marketingový mix, možnosti synergie. Nástroje mobil marketingu - reklamní SMS a MMS, lokační služby, soutěže, ankety a hlasování, věrnostní systémy, mobilní obsah. Subjekty mobil marketingu. M-komerce. Využití pro podnikové aplikace.

  18. Mobile Clouds

    DEFF Research Database (Denmark)

    Fitzek, Frank; Katz, Marcos

    A mobile cloud is a cooperative arrangement of dynamically connected communication nodes sharing opportunistic resources. In this book, authors provide a comprehensive and motivating overview of this rapidly emerging technology. The book explores how distributed resources can be shared by mobile...... examples of mobile clouds applications, based on both existing commercial initiatives as well as proof-of-concept test-beds. Visions and prospects are also discussed, paving the way for further development. As mobile networks and social networks become more and more reliant on each other, the concept of...

  19. Tone calibration technique: A digital signaling scheme for mobile applications

    Science.gov (United States)

    Davarian, F.

    1986-01-01

    Residual carrier modulation is conventionally used in a communication link to assist the receiver with signal demodulation and detection. Although suppressed carrier modulation has a slight power advantage over the residual carrier approach in systems enjoying a high level of stability, it lacks sufficient robustness to be used in channels severely contaminated by noise, interference and propagation effects. In mobile links, in particular, the vehicle motion and multipath waveform propagation affect the received carrier in an adverse fashion. A residual carrier scheme that uses a pilot carrier to calibrate a mobile channel against multipath fading anomalies is described. The benefits of this scheme, known as tone calibration technique, are described. A brief study of the system performance in the presence of implementation anomalies is also given.

  20. Bipolar carrier transport in tris(8-hydroxy-quinolinato) aluminum observed by impedance spectroscopy measurements

    Science.gov (United States)

    Ishihara, Shingo; Hase, Hiroyuki; Okachi, Takayuki; Naito, Hiroyoshi

    2011-08-01

    We studied bipolar carrier transport in tris(8-hydroxy-quinolinato) aluminum (Alq3) thin films using impedance spectroscopy (IS). Two transit times were observed in the impedance spectra of the Alq3 double-injection diodes. The mobilities determined from the transit times are in good agreement with the electron and the hole mobilities in Alq3 measured by IS using single injection diodes and by the time-of-flight transient photocurrent technique. The bipolar carrier transport observed in Alq3 shows that the carrier recombination of Alq3 is weak on the basis of the simulation [M. Schmeits, J. Appl. Phys. 101, 084508 (2007)]. Simultaneous measurements of electron and hole mobilities are useful in the study of charge-carrier transport in active layers in organic light-emitting diodes and organic solar cells.

  1. Autonomous component carrier selection

    DEFF Research Database (Denmark)

    Garcia, Luis Guilherme Uzeda; Pedersen, Klaus; Mogensen, Preben

    2009-01-01

    in local areas, basing our study case on LTE-Advanced. We present extensive network simulation results to demonstrate that a simple and robust interference management scheme, called autonomous component carrier selection allows each cell to select the most attractive frequency configuration; improving...... management and efficient system operation. Due to the expected large number of user-deployed cells, centralized network planning becomes unpractical and new scalable alternatives must be sought. In this article, we propose a fully distributed and scalable solution to the interference management problem...

  2. Mobile Semiotics - signs and mobilities

    DEFF Research Database (Denmark)

    Jensen, Ole B.

    This paper is about how to comprehend the mobile condition of contemporary life with a particular view to the signifying dimension of the environment and its ‘readability’. The paper explores the potentials of semiotics and its relationship to the new mobilities literature. The theoretical scope is...... therefore an attempt to mobilize semiotics by drawing on a central body of theory within and adjacent to the discipline. For instance the founding works of C. S. Peirce will be related to the contemporary notions of ‘geosemiotics’ by Scollon & Scollon. The paper’s theoretical claim is that semiotics hold a...... potential for mobilities studies if the awareness of seeing the environment as a semiotic layer and system can be sensitized to the insights of the ‘mobilities turn’. Empirically the paper tentatively explores the usefulness of a mobile semiotics approach to cases such as street signage, airport design, and...

  3. Mobile phones and mobile communication

    DEFF Research Database (Denmark)

    Ling, Richard; Donner, Jonathan

    With staggering swiftness, the mobile phone has become a fixture of daily life in almost every society on earth. In 2007, the world had over 3 billion mobile subscriptions. Prosperous nations boast of having more subscriptions than people. In the developing world, hundreds of millions of people who...... could never afford a landline telephone now have a mobile number of their own. With a mobile in our hand many of us feel safer, more productive, and more connected to loved ones, but perhaps also more distracted and less involved with things happening immediately around us. Written by two leading...... researchers in the field, this volume presents an overview of the mobile telephone as a social and cultural phenomenon. Research is summarized and made accessible though detailed descriptions of ten mobile users from around the world. These illustrate popular debates, as well as deeper social forces at work...

  4. NREL Studies Carrier Separation and Transport in Perovskite Solar Cells

    Energy Technology Data Exchange (ETDEWEB)

    2016-01-01

    NREL scientists studied charge separation and transport in perovskite solar cells by determining the junction structure across the solar device using the nanoelectrical characterization technique of Kelvin probe force microscopy. The distribution of electrical potential across both planar and porous devices demonstrates a p-n junction structure at the interface between titanium dioxide and perovskite. In addition, minority-carrier transport within the devices operates under diffusion/drift. Clarifying the fundamental junction structure provides significant guidance for future research and development. This NREL study points to the fact that improving carrier mobility is a critical factor for continued efficiency gains in perovskite solar cells.

  5. Mobile phone

    International Nuclear Information System (INIS)

    Almost the entire Norwegian population has cell phone. The usefulness of the cell phone is great, but can use a mobile phone to health or discomfort? How can exposure be reduced? NRPA follows research and provides advice on mobile phone use. (AG)

  6. Spectroscopy of Charge Carriers and Traps in Field-Doped Single Crystal Organic Semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Xiaoyang

    2014-12-10

    The proposed research aims to achieve quantitative, molecular level understanding of charge carriers and traps in field-doped crystalline organic semiconductors via in situ linear and nonlinear optical spectroscopy, in conjunction with transport measurements and molecular/crystal engineering. Organic semiconductors are emerging as viable materials for low-cost electronics and optoelectronics, such as organic photovoltaics (OPV), organic field effect transistors (OFETs), and organic light emitting diodes (OLEDs). Despite extensive studies spanning many decades, a clear understanding of the nature of charge carriers in organic semiconductors is still lacking. It is generally appreciated that polaron formation and charge carrier trapping are two hallmarks associated with electrical transport in organic semiconductors; the former results from the low dielectric constants and weak intermolecular electronic overlap while the latter can be attributed to the prevalence of structural disorder. These properties have lead to the common observation of low charge carrier mobilities, e.g., in the range of 10-5 - 10-3 cm2/Vs, particularly at low carrier concentrations. However, there is also growing evidence that charge carrier mobility approaching those of inorganic semiconductors and metals can exist in some crystalline organic semiconductors, such as pentacene, tetracene and rubrene. A particularly striking example is single crystal rubrene (Figure 1), in which hole mobilities well above 10 cm2/Vs have been observed in OFETs operating at room temperature. Temperature dependent transport and spectroscopic measurements both revealed evidence of free carriers in rubrene. Outstanding questions are: what are the structural features and physical properties that make rubrene so unique? How do we establish fundamental design principles for the development of other organic semiconductors of high mobility? These questions are critically important but not comprehensive, as the nature of

  7. Restricted Mobilities

    DEFF Research Database (Denmark)

    Nielsen, Mette; Lassen, Claus

    2012-01-01

    exclusion and stratification mechanisms. In conclusion the article therefore suggests that future urban research and planning also needs a mobile understanding of spaces in the cities and how different mobility systems play an important role to sustain the exclusiveness that often characterises the private......Privatisation of public spaces in the contemporary city has increased during the last decades but only few studies have approached this field from a mobility perspective. Therefore the article seeks to rectify this by exploring two Australian examples of private spaces in the city; gated...... communities and shopping centres through mobility lenses. The article shows how different mobility systems enable and restrict the public access to private-public spaces, and it points out that proprietary communities create an unequal potential for human movement and access in the city. The main argument in...

  8. Mobilities Design

    DEFF Research Database (Denmark)

    Jensen, Ole B.; Lanng, Ditte Bendix; Wind, Simon

    2016-01-01

    In this paper, we identify the nexus between design (architecture, urban design, service design, etc.) and mobilities as a new and emerging research field. In this paper, we apply a “situational mobilities” perspective and take point of departure in the pragmatist question: “What design decisions...... and interventions affords this particular mobile situation?” The paper presents the contours of an emerging research agenda within mobilities research. The advent of “mobilities design” as an emerging research field points towards a critical interest in the material as well as practical consequences...... well as policy-making. The paper proposes that increased understanding of the material affordances facilitated through design provides important insight to planning and policymaking that at times might be in risk of becoming too detached from the everyday life of the mobile subject within contemporary...

  9. Intensive mobilities:

    DEFF Research Database (Denmark)

    Vannini, Phillip; Bissell, David; Jensen, Ole B.

    This paper explores the intensities of long distance commuting journeys as a way of exploring how bodily sensibilities are being changed by the mobilities that they undertake. The context of this paper is that many people are travelling further to work than ever before owing to a variety of factors...... which relate to transport, housing and employment. Yet we argue that the experiential dimensions of long distance mobilities have not received the attention that they deserve within geographical research on mobilities. This paper combines ideas from mobilities research and contemporary social theory...... with fieldwork conducted in Canada, Denmark and Australia to develop our understanding of the experiential politics of long distance workers. Rather than focusing on the extensive dimensions of mobilities that are implicated in patterns and trends, our paper turns to the intensive dimensions of this...

  10. Designing Mobilities

    DEFF Research Database (Denmark)

    Jensen, Ole B.

    How is the width of the pavement shaping the urban experience? How is the material design of transport infrastructure and mobile technology affording social interaction in everyday life spaces? How do people inhabit these spaces with their bodies and in accordance to social and cultural norms......? These are some of the questions that this book raises in order to explore how the design of mobile sites and situations affect people's everyday life. The book takes point of departure in the author's book 'Staging Mobilities' (Routledge, 2013) in which it is argued that mobility is much more than...... mundane acts of moving in the city. 'Designing Mobilities' is based on more than a decade of academic research by Professor of Urban Theory, Ole B. Jensen and a must-read for students and scholars with an interest in urban studies, urban design, architecture, urban planning, transport planning and...

  11. Multiple carrier transport in N-face indium nitride

    International Nuclear Information System (INIS)

    We present temperature (20-300 K) dependent multi-carrier measurements of electron species in N-face indium nitride. N-face InN samples were grown to different thicknesses (500-2000 nm) via plasma-assisted molecular beam epitaxy on C-face SiC substrates. Surface and bulk electron transport properties were extracted using a quantitative mobility spectrum analysis. Mobility of both bulk and surface electron species increase with film thickness. The temperature dependence of the mobility of both species differs to that of In-polar samples studied previously, while the mobility of surface electrons is more than twice that of In-polar samples with only a slight corresponding reduction in sheet concentration. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  12. A molecular device based on light controlled charge carrier mobility

    Czech Academy of Sciences Publication Activity Database

    Nešpůrek, Stanislav; Sworakowski, J.; Combellas, C.; Wang, Geng; Weiter, M.

    2004-01-01

    Roč. 234, 1-4 (2004), s. 395-402. ISSN 0169-4332. [International Conference on the Formation of Semiconductor Interfaces /9./. Madrid, 15.09.2003-19.09.2003] R&D Projects: GA MŠk OC D14.30 Institutional research plan: CEZ:AV0Z4050913 Keywords : electrical properties * photoconductivity * photochromism Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.497, year: 2004

  13. Contention aware mobility prediction routing for intermittently connected mobile networks

    KAUST Repository

    Elwhishi, Ahmed

    2013-04-26

    This paper introduces a novel multi-copy routing protocol, called predict and forward (PF), for delay tolerant networks, which aims to explore the possibility of using mobile nodes as message carriers for end-to-end delivery of the messages. With PF, the message forwarding decision is made by manipulating the probability distribution of future inter-contact and contact durations based on the network status, including wireless link condition and nodal buffer availability. In particular, PF is based on the observations that the node mobility behavior is semi-deterministic and could be predicted once there is sufficient mobility history information. We implemented the proposed protocol and compared it with a number of existing encounter-based routing approaches in terms of delivery delay, delivery ratio, and the number of transmissions required for message delivery. The simulation results show that PF outperforms all the counterpart multi-copy encounter-based routing protocols considered in the study.

  14. Renewable energy carriers: Hydrogen or liquid air/nitrogen?

    International Nuclear Information System (INIS)

    The world's energy demand is met mainly by the fossil fuels today. The use of such fuels, however, causes serious environmental issues, including global warming, ozone layer depletion and acid rains. A sustainable solution to the issues is to replace the fossil fuels with renewable ones. Implementing such a solution, however, requires overcoming a number of technological barriers including low energy density, intermittent supply and mobility of the renewable energy sources. A potential approach to overcoming these barriers is to use an appropriate energy carrier, which can store, transport and distribute energy. The work to be reported in this paper aims to assess and compare a chemical energy carrier, hydrogen, with a physical energy carrier, liquid air/nitrogen, and discuss potential applications of the physical carrier. The ocean energy is used as an example of the renewable energy sources in the work. The assessment and comparison are carried out in terms of the overall efficiency, including production, storage/transportation and energy extraction. The environmental impact, waste heat recovery and safety issues are also considered. It is found that the physical energy carrier may be a better alternative to the chemical energy carrier under some circumstances, particularly when there are waste heat sources.

  15. LIQUIFIED NATURAL GAS (LNG CARRIERS

    Directory of Open Access Journals (Sweden)

    Daniel Posavec

    2010-12-01

    Full Text Available Modern liquefied natural gas carriers are double-bottom ships classified according to the type of LNG tank. The tanks are specially designed to store natural gas cooled to -161°C, the boiling point of methane. Since LNG is highly flammable, special care must be taken when designing and operating the ship. The development of LNG carriers has begun in the middle of the twentieth century. LNG carrier storage space has gradually grown to the current maximum of 260000 m3. There are more than 300 LNG carriers currently in operation (the paper is published in Croatian.

  16. Going Mobile?

    DEFF Research Database (Denmark)

    Tallon, Loic; Froes, Isabel Cristina G.

    2011-01-01

    If the future is mobile, how is the museum community developing within that future? What are the challenges museums face within it? In which directions should we be seeking to evolve our collective knowledge share? It was to gain observations on questions such as these that the 2011 Museums & Mob...... & Mobile survey was developed: 660 museum professionals responded. In this paper the authors highlight nine survey observations that they believe are important to the museum community’s increased understanding of and continued progress within mobile interpretation....

  17. Mobile museology

    DEFF Research Database (Denmark)

    Baggesen, Rikke Haller

    selection of blog posts from the research project blog with three research articles: ‘Museum metamorphosis à la mode’, proposing a fashion perspective on ongoing museum developments; ‘Augmenting the agora: media and civic engagement in museums’, questioning the idea of social media holding a vital potential...... fashionable, the ephemeral, and towards an (ideal) state of change and changeability. This orientation is characterised with the triplet concepts of mobile, mobility, and mobilisation, as related to mobile media and movability; to ‘trans - museal’ mediation; and to the mobilisation of collections, audiences...

  18. Mobile Lexicography

    DEFF Research Database (Denmark)

    Køhler Simonsen, Henrik

    2014-01-01

    Users are already mobile, but the question is to which extent knowledge-based dictionary apps are designed for the mobile user situation. The objective of this article is to analyse the characteristics of the mobile user situation and to look further into the stationary user situation and the...... looked up the same five medical terms while walking around a hospital bed. The data collected during the two tests include external and internal recordings, think-aloud data and interview data. The data were analysed by means of the information scientific star model, cf. (Simonsen 2011:565), and it was...

  19. 14 CFR 382.111 - What services must carriers provide to passengers with a disability on board the aircraft?

    Science.gov (United States)

    2010-01-01

    ... hard-of-hearing, so that these passengers have timely access to information the carrier provides to..., including mobility aids and other assistive devices stowed in the cabin (see also 382.91(c)). To...

  20. Numerical optimization of carrier confinement characteristics in (AlxGa1-xN/AlN)SLs/GaN heterostructures

    International Nuclear Information System (INIS)

    We present numerical optimization of carrier confinement characteristics in (AlxGa1-xN/AlN)SLs/GaN heterostructures in the presence of spontaneous and piezoelectrically induced polarization effects. The calculations were made using a self-consistent solution of the Schrödinger, Poisson, potential and charge balance equations. It is found that the sheet carrier density in GaN channel increases nearly linearly with the thickness of AlN although the whole thickness and equivalent Al composition of AlxGa1-xN/AlN superlattices (SLs) barrier are kept constant. This result leads to the carrier confinement capability approaches saturation with thicknesses of AlN greater than 0.6 nm. Furthermore, the influence of carrier concentration distribution on carrier mobility was discussed. Theoretical calculations indicate that the achievement of high sheet carrier density is a trade-off with mobility.

  1. Mobile Commerce

    OpenAIRE

    Maria Cristina Enache

    2016-01-01

    Mobile commerce, or m-commerce, refers to the use of wireless digital devices to enable transactions on the Web. Described more fully in Chapter 3, m-commerce involves the use of wireless networks to connect cell phones, handheld devices such Blackberries, and personal computers to the Web. Once connected, mobile consumers can conduct transactions, including stock trades, in-store price comparisons, banking, travel reservations, and more.

  2. Tuning carrier density at complex oxide interface with metallic overlayer

    Science.gov (United States)

    Zhou, Y.; Shi, Y. J.; Jiang, S. W.; Yue, F. J.; Wang, P.; Ding, H. F.; Wu, D.

    2016-06-01

    We have systematically investigated the electronic transport properties of the LaAlO3/SrTiO3 interfaces with several different metal capping layers. The sheet carrier density can be tuned in a wide range by the metallic overlayer without changing the carrier mobility. The sheet carrier density variation is found to be linearly dependent on the size of metal work function. This behavior is explained by the mechanism of the charge transfer between the oxide interface and the metal overlayer across the LaAlO3 layer. Our results confirm the existence of a built-in electric field in LaAlO3 film with an estimated value of 67.7 eV/Å. Since the metallic overlayer is essential for devices, the present phenomena must be considered for future applications.

  3. Charge carrier coherence and Hall effect in organic semiconductors

    OpenAIRE

    Yi, H. T.; Gartstein, Y. N.; Podzorov, V.

    2016-01-01

    Hall effect measurements are important for elucidating the fundamental charge transport mechanisms and intrinsic mobility in organic semiconductors. However, Hall effect studies frequently reveal an unconventional behavior that cannot be readily explained with the simple band-semiconductor Hall effect model. Here, we develop an analytical model of Hall effect in organic field-effect transistors in a regime of coexisting band and hopping carriers. The model, which is supported by the experimen...

  4. Multi-User Interference Cancellation Scheme(s) for Muliple Carrier Frequency Offset Compensation in Uplink OFDMA

    DEFF Research Database (Denmark)

    Nguyen, Huan Cong; Carvalho, Elisabeth De; Prasad, Ramjee

    2006-01-01

    We consider the uplink of an Orthogonal Frequency Division Multiple Access (OFDMA)-based system, where each Mobile Station (MS) experiences a different Carrier Frequency Offset (CFO). Uncorrected CFO destroy the orthogonality among subcarriers, which could cause severe Inter-Carrier Interference ...

  5. Positron mobility in perylene

    International Nuclear Information System (INIS)

    Based on Doppler-shift measurements we have determined the positron drift velocity u in a high-purity monoclinic α-perylene single crystal as a function of applied electric field F and temperature. The electric field is applied as a triangular wave with a maximum field Fmax. At low fields the drift velocity displays a linear field dependence, while it assumes a sublinear field dependence above a characteristic velocity vs=50 km/s and finally tends to saturate at 110 km/s, presumably due to optical-phonon generation above a certain threshold kinetic energy. Unlike in the case of diamond, vs is much greater than the longitudinal sound velocity in the solid. By fitting the observed nonlinear electric-field dependence of u to a Shockley expression for acoustic deformation potential scattering of ''warm'' charge carriers we extract the zero-field limit of the positron mobility μ0 along the crystallographic c' axis (c'parallel axb). At 297 K μ0=(136±3±14) cm2 V-1 s-1, where the first error is statistical and the second is an estimated ±10% calibration uncertainty. Over the temperature range 100--350 K the mobility exhibits a Tn temperature dependence with n=-1.04±0.03, showing a clear departure from the T-3/2 dependence one might expect. Below 100 K μ0 still increases with decreasing temperature, but at a given temperature its value decreases as the maximum applied field Fmax increases, possibly indicating interference caused by the presence of a field-enhanced accumulation of trapped carriers that cause scattering at low temperatures

  6. Designing Mobilities

    DEFF Research Database (Denmark)

    Jensen, Ole B.

    practices. Everyday life mobilities take place in complex socio-technical systems where the over-layering of hard infrastructures, with design codes and protocols shapes the ‘mobile biotopes’ of the everyday life. By exploring the very tangible and concrete designs of for example everyday life transit...... spaces, mobilitiy technologies or urban sites of movement we get much closer to understanding the meaning of mobilities to social interaction and culture. The cases are still representing work-in-progress but will be reported in the book ‘Designing Mobilites’ (Jensen 2013b) and will cover the four cases...... of: motorway ecologies, bicycle systems design, urban shopping malls and a train transit hub....

  7. Carrier transport uphill. I. General

    DEFF Research Database (Denmark)

    Rosenberg, T; Wilbrandt, W

    1963-01-01

    A quantitative treatment of a carrier pump operating with two carrier forms C and Z is presented. Asymmetric metabolic reactions are assumed to transform Z into C on one and C into Z on the other side of the membrane, establishing a carrier cycle. The kinetical consequences of this mechanism are...... worked out with respect to net transport rate, initial rate, unidirectional fluxes including back-flow through the pump, maximum accumulation ratio, competitive inhibition and acceleration, counter transport, and metabolic poisoning. The energetics of the system are treated. The fact that the system...

  8. Carrier transport in amorphous silicon utilizing picosecond photoconductivity

    Science.gov (United States)

    Johnson, A. M.

    1981-08-01

    The development of a high-speed electronic measurement capability permitted the direct observation of the transient photoresponse of amorphous silicon (a-Si) with a time resolution of approximately 10ps. This technique was used to measure the initial mobility of photogenerated (2.1eV) free carriers in three types of a-Si having widely different densities of structural defects (i.e., as prepared by: (1) RF glow discharge (a-Si:H); (2) chemical vapor deposition; and (3) evaporation in ultra-high vacuum). In all three types of a-Si, the same initial mobility of approximately 1 cu cm/Vs at room temperature was found. This result tends to confirm the often-made suggestion that the free carrier mobility is determined by the influence of shallow states associated with the disorder in the random atomic network, and is an intrinsic property of a-Si which is unaffected by the method of preparation. The rate of decay of the photocurrent correlates with the density of structural defects and varies from 4ps to 200ps for the three types of a-Si investigated. The initial mobility of a-Si:H was found to be thermally activated. The possible application of extended state transport controlled by multiple trapping and small polaron formation is discussed.

  9. Mobile Marketing

    OpenAIRE

    Monika Březinová; Michael Rost

    2009-01-01

    This article deals with one of the modern trends in marketing communication, which is mobile marketing. Towards the end of 2008, several projects which use mobile phones for target marketing communication were launched. Commercial SMS´s are sent on the base of agreement or registration of the consumers on special websites, for example hellomobil.cz. The benefit for the consumers is the bonus which can have more forms - not only sending money to the account, free SMS´s/MMS´s and minutes but al...

  10. Mobile Applications

    OpenAIRE

    Semerád, David

    2011-01-01

    The mobile app market is one of the fastest growing in the world. The Apple company has become the most valuated company in the world, mainly due to its App Store. Considering the fact, that nearly all the trends from abroad are soon or later adapted in the Czech Republic, there is quite a big potential value for all the projects on mobile apps including the local market specifics. The subject of this thesis is to consider whether such an app could be successful in such an old school environm...

  11. Basic Stand Alone Carrier Line Items PUF

    Data.gov (United States)

    U.S. Department of Health & Human Services — This release contains the Basic Stand Alone (BSA) Carrier Line Items Public Use Files (PUF) with information from Medicare Carrier claims. The CMS BSA Carrier Line...

  12. Stochastic Ordering based Carrier-to-Interference Ratio Analysis for the Shotgun Cellular Systems

    CERN Document Server

    Madhusudhanan, Prasanna; Youjian,; Liu,; Brown, Timothy X; Baker, Kenneth R

    2011-01-01

    A simple analytical tool based on stochastic ordering is developed to compare the distributions of carrier-to-interference ratio at the mobile station of two cellular systems where the base stations are distributed randomly according to certain non-homogeneous Poisson point processes. The comparison is conveniently done by studying only the base station densities without having to solve for the distributions of the carrier-to-interference ratio, that are often hard to obtain.

  13. Mobility spectrum analytical approach for intrinsic band picture of Ba(FeAs)2

    International Nuclear Information System (INIS)

    Unconventional high temperature superconductivity as well as three-dimensional bulk Dirac cone quantum states arising from the unique d-orbital topology have comprised an intriguing research area in physics. Here we apply a special analytical approach using a mobility spectrum, in which the carrier number is conveniently described as a function of mobility without any hypothesis, both on the types and the numbers of carriers, for the interpretations of longitudinal and transverse electric transport of high quality single crystal Ba(FeAs)2 in a wide range of magnetic fields. We show that the majority carriers are accommodated in large parabolic hole and electron pockets with very different topology as well as remarkably different mobility spectra, whereas the minority carriers reside in Dirac quantum states with the largest mobility as high as 70,000 cm2(Vs)−1. The deduced mobility spectra are discussed and compared to the reported sophisticated first principle band calculations. (paper)

  14. Motor carrier evaluation program plan

    International Nuclear Information System (INIS)

    The US Department of Energy (DOE) Transportation Management Program (TMP) has established a program to assist the DOE field offices and their contractors in evaluating the motor carriers used to transport DOE-owned hazardous and radioactive materials. This program was initiated to provide the DOE field offices with the tools necessary to help ensure, during this period of motor carrier deregulation, that only highly qualified carriers transport radioactive and hazardous commodities for the DOE. This program will assist DOE in maintaining their excellent performance record in the safe transportation of hazardous commodities. The program was also developed in response to public concern surrounding the transportation of hazardous materials. Representatives of other federal agencies, states, and tribal governments, as well as the news media, have expressed concern about the selection and qualification of carriers engaged in the transportation of Highway Route-Controlled Quantities (HRCQ) and Truckload (TL) quantities of radioactive material for the DOE. 8 refs

  15. Content Distribution for Telecom Carriers

    Directory of Open Access Journals (Sweden)

    Ben Falchuk

    2006-08-01

    Full Text Available Distribution of digital content is a key revenue opportunity for telecommunications carriers. As media content moves from analog and physical media-based distribution to digital on-line distribution, a great opportunity exists for carriers to claim their role in the media value chain and grow revenue by enhancing their broadband “all you can eat” high speed Internet access offer to incorporate delivery of a variety of paid content. By offering a distributed peer to peer content delivery capability with authentication, personalization and payment functions, carriers can gain a larger portion of the revenue paid for content both within and beyond their traditional service domains. This paper describes an approach to digital content distribution that leverages existing Intelligent Network infrastructure that many carriers already possess, as well as Web Services.

  16. Mobility Challenges

    DEFF Research Database (Denmark)

    Jensen, Ole B.; Lassen, Claus

    2011-01-01

    This article takes point of departure in the challenges to understand the importance of contemporary mobility. The approach advocated is a cross-disciplinary one drawing on sociology, geography, urban planning and design, and cultural studies. As such the perspective is to be seen as a part of th...

  17. Sustainable Mobility

    DEFF Research Database (Denmark)

    Kjærulff, Aslak Aamot

    This paper combines strands of mobilities theory and planning theory, and develops a qualitative approach to look across emerging planning practices. By actively following 8 Danish urban and transport planners, over the course of 2 years, we learn how their practices have changed, inspired by mob...

  18. Mobil nationalisme

    DEFF Research Database (Denmark)

    Koefoed, Lasse Martin

    2006-01-01

    , varer, mennesker og kapital men derimod en integreret del af disse tendenser. Gennem begrebet mobil nationalisme argumenteres der for en analytisk optik, hvor nationalisme forstås som en proces hvorigennem skiftende relationer og bevægelser mellem forskellige socio-rumlige skalaer som kroppen...

  19. Sustainable bioenergy carriers from wastes

    OpenAIRE

    Pereira, M.A.; Cavaleiro, A. J.; Abreu, A. A.; Costa, J.C.; Sousa, D. Z.; Alves, M.M.

    2012-01-01

    The development of new technologies for renewable energy production is crucial for decreasing the reliance in fossil fuels and improving global sustainability. Waste materials are valuable resources that can be used for the production of energy carriers. Organic wastes can be anaerobically digested to ultimately produce methane. Hydrogen can be recovered from this process, if methanogenesis is inhibited. These energy carriers can also be derived from recalcitrant materials in a two step-proce...

  20. Localization of carriers in a one-dimensional electron system over liquid helium

    Science.gov (United States)

    Gladchenko, S. P.; Kovdrya, Yu. Z.; Nikolaenko, V. A.

    2000-07-01

    The mobility of carriers in a one-dimensional electron system over liquid helium has been measured at the temperature 0.5-1.7 K and for different values of linear electron density. Profiled nylon substrates with some quantity of charge deposited were used for the realization of a one-dimensional electron system. It is shown that electron mobility is dependent on the quantity of the charge on a substrate. Effects observed are explained by the localization of electrons moving in the random potential created by the substrates charge. It is supposed that at low temperatures the movement of carriers is determined by quantum effects.

  1. Mobile cosmetics advisor: an imaging based mobile service

    Science.gov (United States)

    Bhatti, Nina; Baker, Harlyn; Chao, Hui; Clearwater, Scott; Harville, Mike; Jain, Jhilmil; Lyons, Nic; Marguier, Joanna; Schettino, John; Süsstrunk, Sabine

    2010-01-01

    Selecting cosmetics requires visual information and often benefits from the assessments of a cosmetics expert. In this paper we present a unique mobile imaging application that enables women to use their cell phones to get immediate expert advice when selecting personal cosmetic products. We derive the visual information from analysis of camera phone images, and provide the judgment of the cosmetics specialist through use of an expert system. The result is a new paradigm for mobile interactions-image-based information services exploiting the ubiquity of camera phones. The application is designed to work with any handset over any cellular carrier using commonly available MMS and SMS features. Targeted at the unsophisticated consumer, it must be quick and easy to use, not requiring download capabilities or preplanning. Thus, all application processing occurs in the back-end system and not on the handset itself. We present the imaging pipeline technology and a comparison of the services' accuracy with respect to human experts.

  2. Ultrafast Probe of Carrier Diffusion and Nongeminate Processes in a Single CdSSe Nanowire

    Directory of Open Access Journals (Sweden)

    Peter S. Eldridge

    2015-01-01

    Full Text Available We measure ultrafast carrier dynamics in a single CdSSe nanowire at different excitation fluences using an ultrafast Kerr-gated microscope. The time-resolved emission exhibits a dependence on excitation fluence, with the onset of the emission varying on the picosecond time scale with increasing laser power. By fitting the emission to a model for amplified spontaneous emission (ASE, we are able to extract the nonradiative carrier recombination lifetime and nongeminate recombination constant. The extracted nongeminate recombination constant suggests that our measurement technique allows the access to the nondiffusion limited recombination regime in nanowires with low carrier mobility.

  3. Effect of Carrier Differences on Spin Polarized Injection into Organic and Inorganic Semiconductors

    Institute of Scientific and Technical Information of China (English)

    REN Jun-Feng; XIU Ming-Xia

    2008-01-01

    Spin polarized injection into organic and inorganic semiconductors are studied theoretically from the spin diffusion theory and Ohm's law, and the emphases are placed on the effect of the carrier differences on the current spin polarization. The mobility and the spin-Rip time of carriers in organic and inorganic semiconductors are different. From the calculation, it is found that current spin polarization at a ferromagnetic/organic interface is higher than that at a ferromagnetic/inorganic interface because of different carriers in them. Effects of the conductivity matching, the spin dependent interfacial resistances, and the balk spin polarization of the ferromagnetic layer on the spin polarized injection are also discussed.

  4. Mobile-to-mobile wireless channels

    CERN Document Server

    Zajic, Alenka

    2013-01-01

    Present-day mobile communications systems can be classified as fixed-to-mobile because they allow mobility on only one end (e.g. the mobile phone to a fixed mobile operator's cell tower). In answer to the consumer demand for better coverage and quality of service, emerging mobile-to-mobile (M-to-M) communications systems allow mobile users or vehicles to directly communicate with each other. This practical book provides a detailed introduction to state-of-the-art M-to-M wireless propagation. Moreover, the book offers professionals guidance for rapid implementation of these communications syste

  5. Mobile Customer Relationship Management and Mobile Security

    Science.gov (United States)

    Sanayei, Ali; Mirzaei, Abas

    The purpose of this study is twofold. First, in order to guarantee a coherent discussion about mobile customer relationship management (mCRM), this paper presents a conceptualization of mCRM delineating its unique characteristics because of Among the variety of mobile services, considerable attention has been devoted to mobile marketing and in particular to mobile customer relationship management services. Second, the authors discusses the security risks in mobile computing in different level(user, mobile device, wireless network,...) and finally we focus on enterprise mobile security and it's subgroups with a series of suggestion and solution for improve mobile computing security.

  6. Extraction and scattering analyses of 2D and bulk carriers in epitaxial graphene-on-SiC structure

    OpenAIRE

    Lisesivdin, S. B.; Atmaca, G.; ARSLAN, E.; Cakmakyapan, S; Kazar, O; Butun, S.; ul-Hassan, Jawad; Janzén, Erik; E. Ozbay

    2014-01-01

    Hall effect measurements of a graphene-on-SiC system were carried out as a function of temperature (1.8-200 K) at a static magnetic field (0.51) With the analysis of temperature dependent single-field Hall data with the Simple Parallel Conduction Extraction Method (SPCEM), bulk and two-dimensional (2D) carrier densities and mobilities were extracted successfully. Bulk carrier is attributed to SIC substrate and 2D carrier is attributed to the graphene layer. For each SPCEM extracted carrier da...

  7. Mobile Usability

    DEFF Research Database (Denmark)

    Aryana, Bijan; Clemmensen, Torkil

    2013-01-01

    In this article, a country specific comparative mobile usability study is presented, using Iran and Turkey as the two chosen emerging/emergent nation exemplars of smartphone usage and adoption. In a focus group study, three mobile applications were selected by first-time users of smartphones....... In both countries, the music player application was tested, wherein common patterns of accessing and sorting songs emerged. Whereas the Iranian users appeared to be more interested in social networking via use of an SMS service, the Turkish users tended to prefer to apply hierarchies to their own daily...... personal contacts. The results and analysis establish the existence of country specific issues and concerns, as well as reveal generic usability issues. The article concludes that the source of these issues is most likely due to a combination of certain contextual features endemic to both Iran and Turkey...

  8. Mobile Misfortune

    DEFF Research Database (Denmark)

    Vigh, Henrik Erdman

    2015-01-01

    termination of the mobility it enables. This article, thus, looks at the motives and manners in which young men in Bissau become caught up in transnational flows of cocaine. It shows how motion is emotively anchored and affectively bound: tied to and directed toward a feeling of worth and realisation of being......, and how migration from the global South often has negative potentiality as an end-point via the ascription of illegality and condition of deportability that shade it....

  9. The African Mobile Story

    DEFF Research Database (Denmark)

    This book identifies the factors that has enabled the growth of mobile telephony in Africa. The book covers the regulatory factors, the development and usage of mobile application, mobile security and sustainable power source for mobile networks......This book identifies the factors that has enabled the growth of mobile telephony in Africa. The book covers the regulatory factors, the development and usage of mobile application, mobile security and sustainable power source for mobile networks...

  10. Motor Carrier Evaluation Program procedure

    International Nuclear Information System (INIS)

    The US Department of Energy (DOE) Transportation Management Division (DOE-TMD) has the overall responsibility to provide a well-managed transportation program for the safe, efficient, and economical transportation of DOE-owned material. In the performance of these duties, the DOE-TMD has established an exemplary safety record in the transportation of hazardous materials. The DOE recognizes that its responsibility for hazardous material does not end when the shipments leave the DOE sites. A special partnership is needed between the DOE, the DOE contractors, and the carriers chosen to transport hazardous materials. As in any partnership, it is critical that DOE know essential information about its partner in this joint venture. In fulfillment of its responsibility for the safe transportation of radioactive materials as well as other hazardous commodities and wastes routinely shipped from many DOE locations nationwide, the DOE-TMD has developed this policy for a motor carrier evaluation program. It is the intent of the DOE-TMD that this Motor Carrier Evaluation Program be implemented at all DOE locations to the fullest extent practicable. This program will assist in the evaluation of carriers transporting Highway Route Controlled Quantities (HRCQ) of radioactive material, because these shipments frequently are in the ''public eye.'' The program will also evaluate truckload (TL) quantity transporters of hazardous materials, including radioactive material and chemical wastes. The program has also recently been expanded to include motor carriers transporting less-than-truckload (LTL) quantities of these materials

  11. Carrier sense data highway system

    Science.gov (United States)

    Frankel, Robert

    1984-02-14

    A data transmission system includes a transmission medium which has a certain propagation delay time over its length. A number of data stations are successively coupled to the transmission medium for communicating with one another. Each of the data stations includes a transmitter for originating signals, each signal beginning with a carrier of a duration which is at least the propagation delay time of the transmission medium. Each data station also includes a receiver which receives other signals from other data stations and inhibits operation of the transmitter at the same data station when a carrier of another signal is received.

  12. Mobile Payments : Comparison of Mobile Wallet Concepts

    OpenAIRE

    Narayan, Srikant

    2013-01-01

    Mobile payments are an emerging trend and an alternative to traditional payment methods. Mobile payments involve the usage of the mobile phone to handle credit transfers during purchase of goods and peer to peer money transfers referred to as mobile wallet service, instead of depending on bank cards and cash. In this scenario, while the mobile wallet industry still being in its infancy there exist a few drivers of mobile wallet solutions aiming to create a de-facto standard in the mobile mark...

  13. Effects of edge chemistry doping on graphene nanoribbon mobility

    OpenAIRE

    Ouyang*, Yijian; Sanvito, Stefano; Guo, Jing

    2011-01-01

    Doping of semiconductor is necessary for various device applications. Exploiting chemistry at its reactive edges was shown to be an effective way to dope an atomically thin graphene nanoribbon (GNR) for realizing new devices in recent experiments. The carrier mobility limited by edge doping is studied as a function of the GNR width, doping density, and carrier density by using ab initio density functional and parameterized tight binding simulations combined with the non-equilibrium Green's fu...

  14. 75 FR 72863 - Motor Carrier Safety Advisory Committee Public Meeting

    Science.gov (United States)

    2010-11-26

    ... Federal Motor Carrier Safety Administration Motor Carrier Safety Advisory Committee Public Meeting AGENCY: Federal Motor Carrier Safety Administration, DOT. ACTION: Notice of Motor Carrier Safety Advisory Committee Meeting. SUMMARY: FMCSA announces that the Agency's Motor Carrier Safety Advisory Committee...

  15. 76 FR 12214 - Motor Carrier Safety Advisory Committee Public Meeting

    Science.gov (United States)

    2011-03-04

    ... Federal Motor Carrier Safety Administration Motor Carrier Safety Advisory Committee Public Meeting AGENCY: Federal Motor Carrier Safety Administration, DOT. ACTION: Notice: Announcement of Motor Carrier Safety Advisory Committee meeting; request for comment. SUMMARY: The Federal Motor Carrier Safety...

  16. 75 FR 50797 - Motor Carrier Safety Advisory Committee Public Meeting

    Science.gov (United States)

    2010-08-17

    ... Federal Motor Carrier Safety Administration Motor Carrier Safety Advisory Committee Public Meeting AGENCY: Federal Motor Carrier Safety Administration (FMCSA), DOT. ACTION: Notice of Motor Carrier Safety Advisory Committee Meeting. SUMMARY: FMCSA announces that its Motor Carrier Safety Advisory Committee (MCSAC)...

  17. Mobile Marketing

    OpenAIRE

    Luengo Cascudo, Alberto

    2010-01-01

    El principal objetivo de este proyecto es explicar y entender la importancia del Mobile Marketing como nueva herramienta de negocio en el Marketing empresarial. Para ello, el primer objetivo es entender los dos factores que para mí son la clave de su importancia: la evolución del entorno tecnológico y el cambio en los hábitos del consumidor. Debido a la novedad de esta nueva forma de Marketing y al hecho de que está en constante definición, es básico exponer de la forma más cla...

  18. Robotique Mobile

    OpenAIRE

    Filliat, David

    2011-01-01

    1 Introduction I Les bases de la navigation 2 Les différents types de navigation 3 Les sources d'information 4 Matériels courants en robotique mobile II Navigation réactive 5 Navigation vers un but 6 Évitement d'obstacles 7 Apprentissage par renforcement III Navigation utilisant une carte 8 Localisation, Cartographie et Planification 9 Les représentations de l'environne 10 Localisation 11 Cartographie 12 Planification École d'ingénieur

  19. SC-FDMA for mobile communications

    CERN Document Server

    Abd El-Samie, Fathi E

    2013-01-01

    SC-FDMA for Mobile Communications examines Single-Carrier Frequency Division Multiple Access (SC-FDMA). Explaining this rapidly evolving system for mobile communications, it describes its advantages and limitations and outlines possible solutions for addressing its current limitations. The book explores the emerging trend of cooperative communication with SC-FDMA and how it can improve the physical layer security. It considers the design of distributed coding schemes and protocols for wireless relay networks where users cooperate to send their data to the destination. Supplying you with the re

  20. Mobility Impact on Performance of Mobile Grids

    OpenAIRE

    A. S. Nandeppanavar,; M. N. Birje,; S. S. Manvi,; Shridhar

    2010-01-01

    Wireless mobile grids are one of the emerging grid types, which help to pool the resources of several willing and cooperative mobile devices to resolve a computationally intensive task. The mobile grids exhibit stronger challenges like mobility management of devices, providing transparent access to grid resources, task management and handling of limited resources so that resources are shared efficiently. Task execution on these devices should not be affected by their mobility. The proposed wo...

  1. Optimum Mobility Performance with Mobile IP & SIP

    OpenAIRE

    B. Naresh Kumar; DR. R. V. KRISHNAIAH

    2013-01-01

    Mobility will place an efficient role in now days in the wireless communications. Mobile IP andSIP provide the mobility service to the handset users. The problems in Mobile IP and SIP s are triangular,handoff, Intra domain problems. These problems create signal lose and improper signalling to the user. Toovercome these we provide add of service to the Mobile IP and SIP with the integration of the two services.This service provides optimum performance of the system.

  2. Microscopic observation of carrier-transport dynamics in quantum-structure solar cells using a time-of-flight technique

    International Nuclear Information System (INIS)

    In this study, we propose a carrier time-of-flight technique to evaluate the carrier transport time across a quantum structure in an active region of solar cells. By observing the time-resolved photoluminescence signal with a quantum-well probe inserted under the quantum structure at forward bias, the carrier transport time can be efficiently determined at room temperature. The averaged drift velocity shows linear dependence on the internal field, allowing us to estimate the quantum structure as a quasi-bulk material with low effective mobility containing the information of carrier dynamics. We show that this direct and real-time observation is more sensitive to carrier transport than other conventional techniques, providing better insights into microscopic carrier transport dynamics to overcome a device design difficulty

  3. Microscopic observation of carrier-transport dynamics in quantum-structure solar cells using a time-of-flight technique

    Energy Technology Data Exchange (ETDEWEB)

    Toprasertpong, Kasidit; Fujii, Hiromasa; Sugiyama, Masakazu; Nakano, Yoshiaki [School of Engineering, The University of Tokyo, Bunkyo-ku, Tokyo 113-0032 (Japan); Kasamatsu, Naofumi; Kada, Tomoyuki; Asahi, Shigeo; Kita, Takashi [Graduate School of Engineering, Kobe University, Nada-ku, Kobe 657-8501 (Japan); Wang, Yunpeng; Watanabe, Kentaroh [Research Center for Advanced Science and Technology, The University of Tokyo, Meguro-ku, Tokyo 153-8904 (Japan)

    2015-07-27

    In this study, we propose a carrier time-of-flight technique to evaluate the carrier transport time across a quantum structure in an active region of solar cells. By observing the time-resolved photoluminescence signal with a quantum-well probe inserted under the quantum structure at forward bias, the carrier transport time can be efficiently determined at room temperature. The averaged drift velocity shows linear dependence on the internal field, allowing us to estimate the quantum structure as a quasi-bulk material with low effective mobility containing the information of carrier dynamics. We show that this direct and real-time observation is more sensitive to carrier transport than other conventional techniques, providing better insights into microscopic carrier transport dynamics to overcome a device design difficulty.

  4. Performance comparison of asynchronous orthogonal multi-carrier CDMA in frequency selective channel

    OpenAIRE

    Xiang, G; Ng, TS

    1998-01-01

    Bit error rate (BER) performance of an asynchronous multi-carrier code division multiple access (MC-CDMA) system for the uplink of the mobile communication system with equal gain combining and maximum ratio combining are obtained. Given a fixed bandwidth frequency selective channel, performance of MC-CDMA is compared with that of conventional CDMA and MC-DS-CDMA in numerical results.

  5. Asynchronous Orthogonal Multi-Carrier CDMA Using Equal Gain Combining in Multipath Rayleigh Fading Channel

    OpenAIRE

    Xiang, G; Ng, TS

    1998-01-01

    Performance of an asynchronous orthogonal multi-carrier code division multiple access (MC-CDMA) system for the reverse link of the mobile communication system with equal gain combining is obtained. The performance of MC-CDMA is compared with that of conventional CDMA and MC-DS-CDMA in numerical results in a multipath Rayleigh fading channel.

  6. Mobile Security with Smartcards

    OpenAIRE

    Kilian-Kehr, Roger

    2002-01-01

    Mobility in conjunction with communication facilities in the form of mobile telephony seems to be one of the major technology trends observed throughout the last decade. Many experts and analysts expect that the arrival of mobile services such as mobile commerce, location-based services, multi-media messaging, and mobile gaming in the third generation of mobile networks will be the next step in this success story. However, protecting service providers from fraud and mobile users from new thre...

  7. Hot carrier degradation in semiconductor devices

    CERN Document Server

    2015-01-01

    This book provides readers with a variety of tools to address the challenges posed by hot carrier degradation, one of today’s most complicated reliability issues in semiconductor devices.  Coverage includes an explanation of carrier transport within devices and book-keeping of how they acquire energy (“become hot”), interaction of an ensemble of colder and hotter carriers with defect precursors, which eventually leads to the creation of a defect, and a description of how these defects interact with the device, degrading its performance. • Describes the intricacies of hot carrier degradation in modern semiconductor technologies; • Covers the entire hot carrier degradation phenomenon, including topics such as characterization, carrier transport, carrier-defect interaction, technological impact, circuit impact, etc.; • Enables detailed understanding of carrier transport, interaction of the carrier ensemble with the defect precursors, and an accurate assessment of how the newly created defects imp...

  8. Theory of transport phenomena in polycrystalline lead chalcogenide films. Mobility. Nondegenerate statistics

    Energy Technology Data Exchange (ETDEWEB)

    Atakulov, Sh. B., E-mail: atakulovsh@mail.ru; Zaynolobidinova, S. M. [Fergana State University (Uzbekistan); Nabiev, G. A., E-mail: gulamnabi@mail.ru [Fergana Polytechnical Institute (Uzbekistan); Nabiyev, M. B. [Fergana State University (Uzbekistan); Yuldashev, A. A. [Fergana Polytechnical Institute (Uzbekistan)

    2013-07-15

    The mobility of nondegenerate electrons in quasi-single-crystal and polycrystalline PbTe films is experimentally investigated. The results obtained are compared with the data for bulk crystals at the same charge-carrier concentration. Under the assumption of limitation of the charge-carrier mobility by intercrystallite potential barriers, electron transport in an electric field is theoretically considered. The theoretical results are in good agreement with the experiment.

  9. 47 CFR 25.143 - Licensing provisions for the 1.6/2.4 GHz mobile-satellite service and 2 GHz mobile-satellite...

    Science.gov (United States)

    2010-10-01

    ...-satellite service and 2 GHz mobile-satellite service. 25.143 Section 25.143 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS Applications and Licenses Space Stations § 25.143 Licensing provisions for the 1.6/2.4 GHz mobile-satellite service and 2...

  10. Scanning Kelvin Probe Microscopy Investigation of the Role of Minority Carriers on the Switching Characteristics of Organic Field-Effect Transistors.

    Science.gov (United States)

    Hu, Yuanyuan; Pecunia, Vincenzo; Jiang, Lang; Di, Chong-An; Gao, Xike; Sirringhaus, Henning

    2016-06-01

    A method based on scanning Kelvin probe microscopy is developed to probe the effects of minority carriers on the switching characteristics of organic field-effect transistors. The mobility of the minority carriers is extracted and the role they play in screening of the gate potential in the OFF state and in recombination of trapped majority carriers trapped after an ON state is understood. PMID:27059526

  11. ON THE PROBLEM WITH DETERMINATION OF COOLING SYSTEM PARAMETERS IN MOBILE VEHICLE ENGINES

    Directory of Open Access Journals (Sweden)

    A. Yakubovich

    2014-10-01

    Full Text Available The paper proposes a methodology for determination of fluid and air contour parameters of cooling systems in mobile vehicle engines that permits to calculate a cooling system, to analyze influence of heat carrier expendable parameters on a temperature mode, surfaces of radiator cooling, and also temperature of heat-carriers and environment. 

  12. Comparison of CDMA and FDMA for the MobileStar(sm) system

    Science.gov (United States)

    Jacobs, I. M.; Gilhousen, K. S.; Weaver, L. A.; Renshaw, K.; Murphy, T.

    1988-01-01

    Spread-spectrum code division multiple access (CDMA) and single channel per carrier frequency division multiple access (FDMA) systems are compared for spectrum efficiency. CDMA is shown to have greater maximum throughput than FDMA for the MobileStar(sm) system which uses digital voice activated carriers and directive circularly polarized satellite antennas.

  13. ON THE PROBLEM WITH DETERMINATION OF COOLING SYSTEM PARAMETERS IN MOBILE VEHICLE ENGINES

    OpenAIRE

    A. Yakubovich; Tarasenko, V.

    2014-01-01

    The paper proposes a methodology for determination of fluid and air contour parameters of cooling systems in mobile vehicle engines that permits to calculate a cooling system, to analyze influence of heat carrier expendable parameters on a temperature mode, surfaces of radiator cooling, and also temperature of heat-carriers and environment. 

  14. Electromigration of carrier-free radionuclides. 13

    International Nuclear Information System (INIS)

    Using a special type of on line electromigration measurements of γ-emitting radionuclides in homogeneous aqueous electrolytes free of supporting materials the electromigration behaviour of the carrier-free 241Am-Am(III) in inert electrolytes, μ = 0.1 (ClO4-), T = 298.1(1) K, was studied. Basing on experimental dependencies of the overall ion mobilities of 241Am-Am(III) on pH between pH 5.5 and 12.9 the stoichiometric hydrolysis constants pβ3 = 28.8(9) and pK1 = 6.9(2) were obtained. For K4 a limitation of pK4 > 13.9(3) was possible, because no formation of anionic hydrolysis products in solutions pH 241Am-Am(III) degrees in the range pH 5.5 - 3 from +6.85(15) up to +5.50(15) · 10-4 cm2s-1V-1. Dependencies of this effect on overall ionic strength, inert electrolyte anion, and temperature of the electrolytes were studied in detail both in acidic and neutral solutions. (author)

  15. Mobile shearography

    Science.gov (United States)

    Kalms, Michael; Jueptner, Werner

    2005-04-01

    By reason of their sensitivity, accuracy and non-contact as well as non-destructive characteristics, modern optical methods such as digital speckle shearography have found an increasing interest for NDT applications on the factory floor. With new carbon filter technologies and other lightweight constructions in aircraft and automotive manufacturing, adapted examination designs and especially developed testing methods are necessary. Shearography as a coherent optical method has been widely accepted as an useful NDT tool. It is a robust interferometric method to determine locations with maximum stress on various material structures. However, limitations of this technique can be found in the bulky equipment components, the interpretation of the complex sherographic result images and at the work with non-cooperative surfaces (dark absorber, bright shining reflectors). We report a mobile shearography system that was especially designed for investigations at aircraft and automotive constructions.

  16. Mobile video with mobile IPv6

    CERN Document Server

    Minoli, Daniel

    2012-01-01

    Increased reliance on mobile devices and streaming of video content are two of the most recent changes that have led those in the video distribution industry to be concerned about the shifting or erosion of traditional advertising revenues. Infrastructure providers also need to position themselves to take advantage of these trends. Mobile Video with Mobile IPv6provides an overview of the current mobile landscape, then delves specifically into the capabilities and operational details of IPv6. The book also addresses 3G and 4G services, the application of Mobile IPv6 to streaming and other mobil

  17. The transport of carriers and localization in a one-dimensional electron system over liquid helium

    International Nuclear Information System (INIS)

    The carrier mobility in an electron close to-one-dimensional' system over liquid helium is measured. The one-dimensional conducting channels were created using both the curvature of the liquid helium surface covering a profiled dielectric substrate and the pressing electric field which holds the electrons on the bottom of the liquid 'grooves'. The measurements were carried out in the temperature range 0.5-1.6 K with the interval of linear densities (0.5-2.5) 104cm1 and at the generator voltage ranged from 2 to 200 mV. It is shown that the electron mobility for a clean substrate is determined by the interaction with helium atoms in vapor and ripplon; the experimental results are in satisfactory agreement with the theoretical calculation made with the supposition of the absence of carrier localization. It is found that for substrates with surface charge or defects the mobility decreases in comparison with that for the clean substrate. At T<1 K the mobility is essentially independent of temperature or slightly decreases with it. It is found that the frequency of plasma oscillations propagating through the system of parallel channels increases with decreasing electron mobility. The effects observed may be explained by the localization in the one-dimensional system and the diffusive movement of the carriers hopped from one localization state to another

  18. Application of photoconductivity decay and photocurrent generation methods for determination of minority carrier lifetime in silicon

    Indian Academy of Sciences (India)

    S N Singh; R Gandotra; P K Singh; B C Chakravarty

    2005-07-01

    Minority carrier lifeline, , is one of the most important parameters which has a decisive effect on the performance of silicon devices based on excess carriers. The value of is greatly affected by the presence of impurities and defects in silicon and its value provides a fair indication of quality of the material. Photoconductivity decay (PCD) and photocurrent generation (PCG) methods are simple and low cost methods of measurement of minority carrier lifetime in silicon wafers. However, their application requires care. The PCD method can give quite misleading results in case of polycrystalline wafers if there exists potential barriers at the grain boundaries which may affect majority carrier mobility significantly. PCG needs creation of an induced +––+ structure of substantially good quality that should not degrade with time. For PCG method the measurement under vacuum conditions provides correct and consistent results.

  19. Measurement of charge carrier lifetimes in HgCdTe crystals

    International Nuclear Information System (INIS)

    A method, developed for the determination of both electrical and photoelectrical properties of the same Hgsub(1-x)Cdsub(x)Te samples (around x=0.2), is presented. A system which includes a pulsed 0.9 μm wavelength GaAs light source was designed and constructed for the measurement of charge carrier lifetimes from 20 ns to 20 ms in temperature range 80-300 K. To find the mobility and concentration of the charge carriers, the Hall effect was determined via the van der Pauw method. Electrical and photoelectrical properties of raw material wafers could thus be established. Charge carrier lifetimes in Hgsub(1-x)Cdsub(x)Te, Ge and InSb were measured. The corresponding theoretical expected lifetimes were calculated on the basis of the charge carriers concentration. The experimental results are compared to the theoretical ones and the discrepancies are discussed

  20. Carrier Deformability in Drug Delivery.

    Science.gov (United States)

    Morilla, Maria Jose; Romero, Eder Lilia

    2016-01-01

    Deformability is a key property of drug carriers used to increase the mass penetration across the skin without disrupting the lipid barrier. Highly deformable vesicles proved to be more effective than conventional liposomes in delivering drugs into and across the mammalian skin upon topical non occlusive application. In the past five years, highly deformable vesicles have been used for local delivery of drugs on joint diseases, skin cancer, atopic dermatitis, would healing, psoriasis, scar treatment, fungal, bacteria and protozoa infections. Promising topical vaccination strategies rely also in this type of carriers. Here we provide an overview on the main structural and mechanical features of deformable vesicles, to finish with an extensive update on their latest preclinical applications. PMID:26675226

  1. Fatigue reliability for LNG carrier

    Institute of Scientific and Technical Information of China (English)

    Xiao Taoyun; Zhang Qin; Jin Wulei; Xu Shuai

    2011-01-01

    The procedure of reliability-based fatigue analysis of liquefied natural gas (LNG) carrier of membrane type under wave loads is presented. The stress responses of the hotspots in regular waves with different wave heading angles and wave lengths are evaluated by global ship finite element method (FEM). Based on the probabilistic distribution function of hotspots' short-term stress-range using spectral-based analysis, Weibull distribution is adopted and discussed for fitting the long-term probabilistic distribution of stress-range. Based on linear cumulative damage theory, fatigue damage is characterized by an S-N relationship, and limit state function is established. Structural fatigue damage behavior of several typical hotspots of LNG middle ship section is clarified and reliability analysis is performed. It is believed that the presented results and conclusions can be of use in calibration for practical design and initial fatigue safety evaluation for membrane type LNG carrier.

  2. Micro Mobility Marketing

    DEFF Research Database (Denmark)

    Hosbond, Jens Henrik; Skov, Mikael B.

    2008-01-01

    Mobile marketing refers to marketing of services or goods using mobile technology and mobile marketing holds potentially great economical opportunities. Traditionally, mobile marketing has been viewed as mobility in the large taking place virtually anywhere, anytime. Further, research shows...... similarities and differences between micro mobility marketing and the traditional mobile marketing in the large. Finally, we suggest areas for further study.Journal of Targeting, Measurement and Analysis for Marketing (2007) 16, 68-77. doi:10.1057/palgrave.jt.5750058; published online 24 December 2007...... considerable number of studies on push-based SMS mobile marketing campaigns. This paper explores a related yet different form of mobile marketing namely micro mobility marketing. Micro mobility marketing denotes mobility in the small, meaning that promotion of goods takes place within a circumscribed location...

  3. Mobile OS Comparative Study

    OpenAIRE

    Joseph, Jyothy; K, Shinto Kurian

    2013-01-01

    In the fast growing mobile revolutionary era, many operating systems are playing vital role in present market. This study is intending to identify the apt and secure mobile based on mobile operating systems capability and user requirements.

  4. Mobile Inquiry Based Learning

    NARCIS (Netherlands)

    Specht, Marcus

    2012-01-01

    Specht, M. (2012, 8 November). Mobile Inquiry Based Learning. Presentation given at the Workshop "Mobile inquiry-based learning" at the Mobile Learning Day 2012 at the Fernuniversität Hagen, Hagen, Germany.

  5. Gemini surfactants as gene carriers

    Directory of Open Access Journals (Sweden)

    Teresa Piskorska

    2010-03-01

    Full Text Available Gemini surfactants are a new class of amphiphilic compounds built from two classic surfactant moieties bound together by a special spacer group. These compounds appear to be excellent for creating complexes with DNA and are effective in mediating transfection. Thanks to their construction, DNA carrier molecules built from gemini surfactants are able to deliver genes to cells of almost any DNA molecule size, unattainable when using viral gene delivery systems. Moreover, they are much safer for living organisms.

  6. Recursive SDN for Carrier Networks

    OpenAIRE

    McCauley, James; Liu, Zhi; Panda, Aurojit; Koponen, Teemu; Raghavan, Barath; Rexford, Jennifer; Shenker, Scott

    2016-01-01

    Control planes for global carrier networks should be programmable (so that new functionality can be easily introduced) and scalable (so they can handle the numerical scale and geographic scope of these networks). Neither traditional control planes nor new SDN-based control planes meet both of these goals. In this paper, we propose a framework for recursive routing computations that combines the best of SDN (programmability) and traditional networks (scalability through hierarchy) to achieve t...

  7. Biocheese: A Food Probiotic Carrier

    OpenAIRE

    J. M. Castro; M. E. Tornadijo; Fresno, J. M.; H. Sandoval

    2015-01-01

    This review describes some aspects related to the technological barriers encountered in the development and stability of probiotic cheeses. Aspects concerning the viability of probiotic cultures in this matrix are discussed and the potential of cheese as a biofunctional food carrier is analyzed, outlying some points related to health and safety. In general, the manufacture of probiotic cheese should have little change when compared with the elaboration of cheese in the traditional way. The ph...

  8. Preventative maintenance of straddle carriers

    Directory of Open Access Journals (Sweden)

    Si Li

    2015-02-01

    Full Text Available Background: Robotic vehicles such as straddle carriers represent a popular form of cargo handling amongst container terminal operators.Objectives: The purpose of this industry-driven study is to model preventative maintenance (PM influences on the operational effectiveness of straddle carriers.Method: The study employs historical data consisting of 21 273 work orders covering a 27-month period. Two models are developed, both of which forecast influences of PM regimes for different types of carrier.Results: The findings of the study suggest that the reliability of the straddle fleet decreases with increased intervals of PM services. The study also finds that three factors – namely resources, number of new straddles, and the number of new lifting work centres – influence the performances of straddles.Conclusion: The authors argue that this collaborative research exercise makes a significant contribution to existing supply chain management literature, particularly in the area of operations efficiency. The study also serves as an avenue to enhance relevant management practice.

  9. Temperature dependence of ballistic mobility in a metamorphic InGaAs/InAlAs high electron mobility transistor

    International Nuclear Information System (INIS)

    We have investigated the temperature dependence of ballistic mobility in a 100 nm-long InGaAs/InAlAs metamorphic high-electron-mobility transistor designed for millimeter-wavelength RF applications. To extract the temperature dependence of quasi-ballistic mobility, our experiment involves measurements of the effective mobility in the low-bias linear region of the transistor and of the collision-dominated Hall mobility using a gated Hall bar of the same epitaxial structure. The data measured from the experiment are consistent with that of modeled ballistic mobility based on ballistic transport theory. These results advance the understanding of ballistic transport in various transistors with a nano-scale channel length that is comparable to the carrier's mean free path in the channel.

  10. Mobile Search and Advertising

    OpenAIRE

    Lovitskii, Vladimir; McCaffery, Colin; Thrasher, Michael; Traynor, David; Wright, Peter

    2009-01-01

    Mobile advertising is a rapidly growing sector providing brands and marketing agencies the opportunity to connect with consumers beyond traditional and digital media and instead communicate directly on their mobile phones. Mobile advertising will be intrinsically linked with mobile search, which has transported from the internet to the mobile and is identified as an area of potential growth. The result of mobile searching show that as a general rule such search result exceed 1...

  11. Trends in Mobile Marketing

    OpenAIRE

    Chocholová, Petra

    2010-01-01

    The principal aim of this thesis is to assess the state of the mobile marketing as of the first quarter of 2011 and to discuss various scenarios of the future development. This thesis defines the terms "mobile marketing" and "mobile advertising" and identifies the main players in the industry. It explores the main categories of mobile advertising such as mobile messaging, in-content and mobile internet advertising. Later, it analyzes the latest trends in the industry and describes in detail t...

  12. Responsible implementation of expanded carrier screening.

    Science.gov (United States)

    Henneman, Lidewij; Borry, Pascal; Chokoshvili, Davit; Cornel, Martina C; van El, Carla G; Forzano, Francesca; Hall, Alison; Howard, Heidi C; Janssens, Sandra; Kayserili, Hülya; Lakeman, Phillis; Lucassen, Anneke; Metcalfe, Sylvia A; Vidmar, Lovro; de Wert, Guido; Dondorp, Wybo J; Peterlin, Borut

    2016-06-01

    This document of the European Society of Human Genetics contains recommendations regarding responsible implementation of expanded carrier screening. Carrier screening is defined here as the detection of carrier status of recessive diseases in couples or persons who do not have an a priori increased risk of being a carrier based on their or their partners' personal or family history. Expanded carrier screening offers carrier screening for multiple autosomal and X-linked recessive disorders, facilitated by new genetic testing technologies, and allows testing of individuals regardless of ancestry or geographic origin. Carrier screening aims to identify couples who have an increased risk of having an affected child in order to facilitate informed reproductive decision making. In previous decades, carrier screening was typically performed for one or few relatively common recessive disorders associated with significant morbidity, reduced life-expectancy and often because of a considerable higher carrier frequency in a specific population for certain diseases. New genetic testing technologies enable the expansion of screening to multiple conditions, genes or sequence variants. Expanded carrier screening panels that have been introduced to date have been advertised and offered to health care professionals and the public on a commercial basis. This document discusses the challenges that expanded carrier screening might pose in the context of the lessons learnt from decades of population-based carrier screening and in the context of existing screening criteria. It aims to contribute to the public and professional discussion and to arrive at better clinical and laboratory practice guidelines. PMID:26980105

  13. Mobile Schools for a Mobile World

    Science.gov (United States)

    Booth, Susan

    2013-01-01

    Overwhelmingly, independent schools are embracing mobile devices--laptops, iPads or other tablets, and smartphones--to enhance teaching and learning. This article describes the results of the "NAIS 2012 Mobile Learning Survey." Among its findings were that 75 percent of NAIS-member schools currently use mobile learning devices in at…

  14. 49 CFR 376.22 - Exemption for private carrier leasing and leasing between authorized carriers.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 5 2010-10-01 2010-10-01 false Exemption for private carrier leasing and leasing... MOTOR CARRIER SAFETY REGULATIONS LEASE AND INTERCHANGE OF VEHICLES Exemptions for the Leasing Regulations § 376.22 Exemption for private carrier leasing and leasing between authorized carriers....

  15. 47 CFR 90.476 - Interconnection of fixed stations and certain mobile stations.

    Science.gov (United States)

    2010-10-01

    ...) SAFETY AND SPECIAL RADIO SERVICES PRIVATE LAND MOBILE RADIO SERVICES Transmitter Control Interconnected....483 and may be interconnected with the facilities of common carriers. (b) Mobile stations used to....35(c)(42), and 90.267 are not subject to the provisions of § 90.477(d)(3) and may be...

  16. Microstructure-mobility correlation in self-organised, conjugated polymer field-effect transistors

    DEFF Research Database (Denmark)

    Sirringhaus, H.; Brown, P.J.; Friend, R.H.;

    2000-01-01

    We have investigated the correlation between polymer microstructure and charge carrier mobility in high-mobility, self-organised field-effect transistors of poly-3-hexyl-thiophene (P3HT). Two different preferential orientations of the microcrystalline P3HT domains with respect to the substrate ha...

  17. Low-cost carriers fare competition effect

    OpenAIRE

    Carmona Benitez, R.B.; Lodewijks, G.

    2010-01-01

    This paper examines the effects that low-cost carriers (LCC’s) produce when entering new routes operated only by full-service carriers (FSC’s) and routes operated by low-cost carriers in competition with full-service carriers. A mathematical model has been developed to determine what routes should be operated by a low-cost carrier with better possibilities to subsist. The proposed model in this paper was set up by analyzing The United States domestic air transport market 2005 year database fr...

  18. Dynamic Charge Carrier Trapping in Quantum Dot Field Effect Transistors.

    Science.gov (United States)

    Zhang, Yingjie; Chen, Qian; Alivisatos, A Paul; Salmeron, Miquel

    2015-07-01

    Noncrystalline semiconductor materials often exhibit hysteresis in charge transport measurements whose mechanism is largely unknown. Here we study the dynamics of charge injection and transport in PbS quantum dot (QD) monolayers in a field effect transistor (FET). Using Kelvin probe force microscopy, we measured the temporal response of the QDs as the channel material in a FET following step function changes of gate bias. The measurements reveal an exponential decay of mobile carrier density with time constants of 3-5 s for holes and ∼10 s for electrons. An Ohmic behavior, with uniform carrier density, was observed along the channel during the injection and transport processes. These slow, uniform carrier trapping processes are reversible, with time constants that depend critically on the gas environment. We propose that the underlying mechanism is some reversible electrochemical process involving dissociation and diffusion of water and/or oxygen related species. These trapping processes are dynamically activated by the injected charges, in contrast with static electronic traps whose presence is independent of the charge state. Understanding and controlling these processes is important for improving the performance of electronic, optoelectronic, and memory devices based on disordered semiconductors. PMID:26099508

  19. Carrier transport and electronic structure in amorphous oxide semiconductor, a-InGaZnO4

    International Nuclear Information System (INIS)

    Carrier transport properties in amorphous oxide semiconductor InGaZnO4 (a-IGZO) thin films were investigated in detail using temperature dependence of Hall measurements. It was found that Hall mobility increased distinctly as carrier concentration increased. Unlikely conventional amorphous semiconductors such as a-Si/H, definite normal Hall voltage signals were observed on the films with carrier concentrations (N e)>1016 cm-3, and Hall mobilities as large as 15 cm2 (Vs)-1 were attained in the films with N e>1020 cm-3. When N e was less than 1019 cm-3, the temperature dependence of Hall mobility showed thermally-activated behavior in spite that carrier concentration was independent of temperature. While, it changed to almost degenerate conduction at N e>1018 cm-3. These behaviors are similar to those observed in single-crystalline IGZO, and are explained by percolation conduction through distributed potential barriers which are formed in the vicinity of the conduction band bottom due to the randomness of the amorphous structure. The effective mass of a-IGZO was estimated to be ∼0.34 m e (m e is the mass of free electron) from optical data, which is almost the same as that of crystalline IGZO (∼0.32 m e)

  20. Cross platform Mobile Applications Development: Mobile Apps Mobility

    OpenAIRE

    Redda, Yonathan Aklilu

    2012-01-01

    In recent years, the mobile computing sector has been having quite a revolution.Mobile computing devices have shed loads of weight, gone slim, achieved mass popularityand a great market penetration. But one of the challenges that has been part ofmobile computing is technology and device fragmentation leaving application developersfor mobile phones bewildered. Platform developers, device manufacturers comewith so many features and functionalities that it has been dicult to provide developerswi...

  1. Mobile commerce

    OpenAIRE

    Παπαδανιήλ, Βασίλειος

    2014-01-01

    Η συνεχής ανάπτυξη των mobile συσκευών και συστημάτων, η εκτεταμένη χρήση του Διαδικτύου, οι ραγδαίες εξελίξεις στις ασύρματες τεχνολογίες, η αυξημένη ζήτηση για υψηλής ταχύτητας διαδραστικές υπηρεσίες πολυμέσων καθώς και η αυξανόμενη ανάγκη για ασφαλή ασύρματη επικοινωνία, οδήγησε στην ανάπτυξη του mobile commerce και στην καθιέρωση του στον επιχειρηματικό κόσμο. Η συνεχής βελτίωση των ασύρματων τεχνολογιών, ιδιαίτερα ως προς την ευελιξία και την ευχρηστία, οδήγησε στην παροχή διαφόρων υπηρε...

  2. Microprobe metrology for direct sheet resistance and mobility characterization

    DEFF Research Database (Denmark)

    Nielsen, Peter Folmer; Petersen, Dirch Hjorth; Lin, Rong;

    2012-01-01

    and patterned wafers. Using the next generation of microRSP probing tools it will be possible to perform both sheet resistance, mobility and active carrier density measurements using the collinear M4PP. In this article we demonstrate the various techniques necessary to perform high quality...

  3. Impact of carriers in oral absorption

    DEFF Research Database (Denmark)

    Gram, Luise Kvisgaard; Rist, Gerda Marie; Lennernäs, Hans; Steffansen, Bente

    Carriers may mediate the permeation across enterocytes for drug substances being organic anions. Carrier mediated permeation for the organic anions estrone-3-sulfate (ES) and glipizide across Caco-2 cells were investigated kinetically, and interactions on involved carriers evaluated. Initial...... with K(m) 44microM and 38microM, respectively. BCRP inhibition affected both absorptive an exsorptive P(EPA) and P(APP) for ES. Glipizide apical P(UP) and absorptive P(APP) were not inhibitable. Basolateral P(UP) for glipizide was inhibitable, its P(EPA) prevented, and P(UP) was saturable with K(m) 56......microM, but exsorptive P(APP) was not affected. Carrier mediated exsorption kinetics for ES are seen at both apical and basolateral membranes, resulting in predominant exsorption despite presence of absorptive carrier(s). Carrier mediated basolateral P(UP) for glipizide was observed, but glipizide P...

  4. Carrier dynamics and terahertz photoconductivity of doped silicon measured by femtosecond pump-terahertz probe spectroscopy

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The carrier dynamics and terahertz photoconductivity in the n-type silicon (n-Si) as well as in the p-type Silicon (p-Si) have been investigated by using femtosecond pump-terahertz probe technique. The measurements show that the relative change of terahertz transmission of p-Si at low pump power is slightly smaller than that of n-Si,due to the lower carrier density induced by the recombination of original holes in the p-type material and the photogenerated electrons. At high pump power,the bigger change of terahertz transmission of p-Si originates from the greater mobility of the carriers compared to n-Si. The transient photoconductivities are calculated and fit well with the Drude-Smith model,showing that the mobility of the photogenerated carriers decreases with the increasing pump power. The obtained results indicate that femtosecond pump-terahertz probe technique is a promising method to investigate the carrier dynamics of semiconductors.

  5. Evaluation of electron mobility in InSb quantum wells by means of percentage-impact

    Science.gov (United States)

    Mishima, T. D.; Edirisooriya, M.; Santos, M. B.

    2014-05-01

    In order to quantitatively analyze the contribution of each scattering factor toward the total carrier mobility, we use a new convenient figure-of-merit, named a percentage impact. The mobility limit due to a scattering factor, which is widely used to summarize a scattering analysis, has its own advantage. However, a mobility limit is not quite appropriate for the above purpose. A comprehensive understanding of the difference in contribution among many scattering factors toward the total carrier mobility can be obtained by evaluating percentage impacts of scattering factors, which can be straightforwardly calculated from their mobility limits and the total mobility. Our percentage impact analysis shows that threading dislocation is one of the dominant scattering factors for the electron transport in InSb quantum wells at room temperature.

  6. Influences of Injection Barrier and Mobility on Recombination Rate and Zone in OLEDs

    Institute of Scientific and Technical Information of China (English)

    ZHU Ru-hui; LI Hong-jian; YAN Ling-ling; HU Jin; PAN Yan-zhi

    2006-01-01

    The luminous efficiency of organic light-emitting devices depends on the recombination probability of electrons injected at the cathode and holes at the anode. A theoretical model to calculate the distribution of current densities and the recombination rate in organic single layer devices is presented taking into account the charge injection process at each electrode, charge transport and recombination in organic layer. The calculated results indicate that efficient single-layer devices are possible by adjusting the barrier heights at two electrodes and the carrier mobilities. Lowering the barrier heights can improve the electroluminescent(EL) efficiency pronouncedly in many cases, and efficient devices are still possible using an ohmic contact to inject the low mobility carrier, and a contact limited contact to inject the high mobility carrier. All in all, high EL efficiency needs to consider sufficient recombination, enough injected carriers and well transport.

  7. Neural nets and chaotic carriers

    CERN Document Server

    Whittle, Peter

    2010-01-01

    ""Neural Nets and Chaotic Carriers"" develops rational principles for the design of associative memories, with a view to applying these principles to models with irregularly oscillatory operation so evident in biological neural systems, and necessitated by the meaninglessness of absolute signal levels. Design is based on the criterion that an associative memory must be able to cope with 'fading data', i.e., to form an inference from the data even as its memory of that data degrades. The resultant net shows striking biological parallels. When these principles are combined with the Freeman speci

  8. Carrier frequencies, holomorphy and unwinding

    CERN Document Server

    Coifman, Ronald R; Wu, Hau-tieng

    2016-01-01

    We prove that functions of intrinsic-mode type (a classical models for signals) behave essentially like holomorphic functions: adding a pure carrier frequency $e^{int}$ ensures that the anti-holomorphic part is much smaller than the holomorphic part $ \\| P_{-}(f)\\|_{L^2} \\ll \\|P_{+}(f)\\|_{L^2}.$ This enables us to use techniques from complex analysis, in particular the \\textit{unwinding series}. We study its stability and convergence properties and show that the unwinding series can stabilize and show that the unwinding series can provide a high resolution time-frequency representation, which is robust to noise.

  9. Technetium diagnostic agent and carrier

    International Nuclear Information System (INIS)

    A stable sup(99m)Tc-labelled radioactive diagnostic agent is produced by contacting sup(99m)Tc-containing pertechnetate with a non-radioactive carrier comprising a chelating agent, a water-soluble reducing agent and a stabilizer. The stabilizer is chosen from ascorbic acid and erythorbic acid and their pharmaceutically acceptable salts and esters. A mole ratio of more than 100 moles ascorbic or erythorbic acid to 1 mole of reducing agent provides a stable composition at high levels of radioactivity

  10. Wuestite - a solar energy carrier

    Energy Technology Data Exchange (ETDEWEB)

    Weidenkaff, A.; Nueesch, P.; Wokaun, A. [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Reller, A. [Hamburg Univ., Hamburg (Germany)

    1997-06-01

    Hydrogen is produced when Wuestite (Fe{sub 1-y}O) is oxidised by water. This reaction is part of a two-step thermochemical metal oxide cycle for the storage of solar energy in the form of chemical energy carriers, characterised by a high chemical potential. The reaction was studied in a tubular furnace with on-line gas analysis and further characterised in detail by DTA und high-temperature X-ray powder diffraction. The influence of non-stoichiometry, morphology and temperature on the mechanism and kinetics of the water-splitting reaction was determined. (author) 3 figs., tabs., 3 refs.

  11. Mobile Operating Systems

    Directory of Open Access Journals (Sweden)

    Vipin Kamboj

    2012-04-01

    Full Text Available Mobile phones are used by every people in today’s life. We use mobile phones without knowing the different factors that a mobile used including its technology, operating system, CPU ,RAM etc. Many types of operating system are used by different mobile. Every operating system has their advantage

  12. TYPOLOGIES OF MOBILE APPLICATIONS

    OpenAIRE

    Ion Ivan; Alin Zamfiroiu2; Dragoş Palaghiţă3

    2013-01-01

    Mobile applications and their particularities are analyzed. Mobile application specific characteristics are defined. Types of applications are identified and analyzed. The paper established differences between mobile applications and mobile application categories. For each identified type the specific structures and development model are identified.

  13. Mobile Operating Systems

    OpenAIRE

    Vipin Kamboj; Hitesh Gupta

    2012-01-01

    Mobile phones are used by every people in today’s life. We use mobile phones without knowing the different factors that a mobile used including its technology, operating system, CPU ,RAM etc. Many types of operating system are used by different mobile. Every operating system has their advantage

  14. 78 FR 66801 - Motor Carrier Safety Advisory Committee; Charter Renewal

    Science.gov (United States)

    2013-11-06

    ... Federal Motor Carrier Safety Administration Motor Carrier Safety Advisory Committee; Charter Renewal AGENCY: Federal Motor Carrier Safety Administration (FMCSA), DOT. ACTION: Announcement of advisory... Committee that provides the Agency with advice and recommendations on motor carrier safety programs...

  15. Next generation mobile broadcasting

    CERN Document Server

    Gómez-Barquero, David

    2013-01-01

    Next Generation Mobile Broadcasting provides an overview of the past, present, and future of mobile multimedia broadcasting. The first part of the book-Mobile Broadcasting Worldwide-summarizes next-generation mobile broadcasting technologies currently available. This part covers the evolutions of the Japanese mobile broadcasting standard ISDB-T One-Seg, ISDB-Tmm and ISDB-TSB; the evolution of the South Korean T-DMB mobile broadcasting technology AT-DMB; the American mobile broadcasting standard ATSC-M/H; the Chinese broadcasting technologies DTMB and CMMB; second-generation digital terrestrial

  16. Mobility anisotropy in monolayer black phosphorus due to scattering by charged impurities

    Science.gov (United States)

    Liu, Yue; Low, Tony; Ruden, P. Paul

    2016-04-01

    We explore the charged-impurity-scattering-limited mobility of electrons and holes in monolayer black phosphorus (BP), a highly anisotropic material. Taking full account of the anisotropic electronic structure in effective mass approximation, the zero-temperature momentum relaxation time and the charge carrier mobility are calculated based on the Boltzmann transport equation. For carrier densities accessible in experiments, we obtain anisotropy ratios of 3-4. These results are somewhat larger than mobility anisotropy ratios determined experimentally for multilayer BP samples, but due to the complex dependence of the scattering rates on the anisotropy, they are strikingly smaller than the effective mass ratios.

  17. Magnetic-Phase Dependence of the Spin Carrier Mean Free Path in Graphene Nanoribbons

    Science.gov (United States)

    Li, Jing; Niquet, Yann-Michel; Delerue, Christophe

    2016-06-01

    We show theoretically that the intrinsic (phonon-limited) carrier mobility in graphene nanoribbons is considerably influenced by the presence of spin-polarized edge states. When the coupling between opposite edges switches from antiferromagnetic to ferromagnetic with increasing carrier density, the current becomes spin polarized and the mean free path rises from 10 nm to micrometers. In the ferromagnetic state, the current flows through one majority-spin channel which is ballistic over micrometers and several minority-spin channels with mean free paths as low as 1 nm. These features predicted in technology-relevant conditions could be nicely exploited in spintronic devices.

  18. Mobile platform security

    CERN Document Server

    Asokan, N; Dmitrienko, Alexandra

    2013-01-01

    Recently, mobile security has garnered considerable interest in both the research community and industry due to the popularity of smartphones. The current smartphone platforms are open systems that allow application development, also for malicious parties. To protect the mobile device, its user, and other mobile ecosystem stakeholders such as network operators, application execution is controlled by a platform security architecture. This book explores how such mobile platform security architectures work. We present a generic model for mobile platform security architectures: the model illustrat

  19. Tenured Public Servant Mobility

    OpenAIRE

    Aline Pauron

    2003-01-01

    The mobility of tenured public servants is studied from three points of view: geographic mobility (defined by a change of regional study and planning area (ZEAT) or department within a ZEAT), socio-economic mobility (change of socio-economic group) and structural mobility (change of ministry or service within a ministry). Geographic mobility is the most frequent, concerning an average 4.2% of staff every year. Not including upgrading (from grade D to grade C and from primary school teacher to...

  20. ON MOBILE MESH NETWORKS

    OpenAIRE

    Namiot, Dmitry

    2015-01-01

    With the advances in mobile computing technologies and the growth of the Net, mobile mesh networks are going through a set of important evolutionary steps. In this paper, we survey architectural aspects of mobile mesh networks and their use cases and deployment models. Also, we survey challenging areas of mobile mesh networks and describe our vision of promising mobile services. This paper presents a basic introductory material for Masters of Open Information Technologies Lab, interested in m...

  1. MOBILE MARKETING FUTURE TRENDS

    OpenAIRE

    CĂTOIU, Iacob; GÂRDAN, Daniel Adrian; GÂRDAN, Doru Lucian

    2010-01-01

    The present article proposes an introspection into the field of a new marketing specialization – mobile marketing. The concept mainly refers to all marketing activities related to the new communication channel – Short Message Service, Multimedia Messaging Service, and internet access from mobile phone. The article provides, at the same time, a marketing perspective about future trends of mobile marketing and mobile media, and also a technical perspective related to the future mobile communica...

  2. Factors affecting blind mobility

    OpenAIRE

    Clark-Carter, David

    1985-01-01

    This thesis contains a survey of the mobility problems of blind people, experimental analysis and evaluation of these problems and suggestions for ways in which the evaluation of mobility performance and the design of mobility aids may be improved. The survey revealed a low level of mobility among blind people, with no significant improvement since a comparable survey in 1967. A group of self taught cane users were identified and their mobility was shown to be poor or potentially dangero...

  3. Carrier detection in xeroderma pigmentosum

    International Nuclear Information System (INIS)

    We were able to detect clinically normal carriers of xeroderma pigmentosum (XP) genes with coded samples of either peripheral blood lymphocytes or skin fibroblasts, using a cytogenetic assay shown previously to detect individuals with cancer-prone genetic disorders. Metaphase cells of phytohemagglutinin-stimulated T-lymphocytes from eight individuals who are obligate heterozygotes for XP were compared with those from nine normal controls at 1.3, 2.3, and 3.3 h after x-irradiation (58 R) during the G2 phase of the cell cycle. Lymphocytes from the XP heterozygotes had twofold higher frequencies of chromatid breaks or chromatid gaps than normal (P less than 10(-5)) when fixed at 2.3 or 3.3 h after irradiation. Lymphocytes from six XP homozygotes had frequencies of breaks and gaps threefold higher than normal. Skin fibroblasts from an additional obligate XP heterozygote, when fixed approximately 2 h after x-irradiation (68 R), had a twofold higher frequency of chromatid breaks and a fourfold higher frequency of gaps than fibroblasts from a normal control. This frequency of aberrations in cells from the XP heterozygote was approximately half that observed in the XP homozygote. The elevated frequencies of chromatid breaks and gaps after G2 phase x-irradiation may provide the basis of a test for identifying carriers of the XP gene(s) within known XP families

  4. Carrier localization in gallium nitride

    Energy Technology Data Exchange (ETDEWEB)

    Wetzel, C. [Lawrence Berkeley National Lab., CA (United States)][California Univ., Berkeley, CA (United States); Walukiewicz, W. [Lawrence Berkeley National Lab., CA (United States); Haller, E.E. [Lawrence Berkeley National Lab., CA (United States)][California Univ., Berkeley, CA (United States)] [and others

    1996-09-01

    In wide bandgap GaN, a large number of interesting and important scientific questions remain to be answered. For example, the large free electron concentration reaching 10{sup 19} to 10{sup 20} cm{sup - 3} in nominally undoped material are ascribed to intrinsic defects because no chemical impurity has been found at such high concentrations. According to theoretical models, a nitrogen vacancy acts as a donor but its formation energy is very large in n-type materials, making this suggestion controversial. We have investigated the nature of this yet unidentified donor at large hydrostatic pressure. Results from infrared reflection and Raman scattering indicate strong evidence for localization of free carriers by large pressures. The carrier density is drastically decreased by two orders of magnitude between 20 and 30 GPa. Several techniques provide independent evidence for results in earlier reports and present the first quantitative analysis. A possible interpretation of this effect in terms of the resonant donor level is presented.

  5. The effect of charged quantum dots on the mobility of a two-dimensional electron gas: How important is the Coulomb scattering?

    International Nuclear Information System (INIS)

    We have investigated the influence of a layer of charged self-assembled quantum dots (QDs) on the mobility of a nearby two-dimensional electron gas (2DEG). Time-resolved transconductance spectroscopy was used to separate the two contributions of the change in mobility, which are: (i) The electrons in the QDs act as Coulomb scatterers for the electrons in the 2DEG. (ii) The screening ability and, hence, the mobility of the 2DEG decreases when the charge carrier density is reduced by the charged QDs, i.e., the mobility itself depends on the charge carrier concentration. Surprisingly, we find a negligible influence of the Coulomb scattering on the mobility for a 2DEG, separated by a 30 nm tunneling barrier to the layer of QDs. This means that the mobility change is completely caused by depletion, i.e., reduction of the charge carrier density in the 2DEG, which indirectly influences the mobility

  6. Design and Development of Mobile Phone Jammer

    Directory of Open Access Journals (Sweden)

    Oyediran Oyebode Olumide

    2016-06-01

    Full Text Available This paper presents the design, implementation, and testing of a dual-band mobile-phone jammer. This jammer works at GSM 900 and GSM 1800 simultaneously and thus jams the four well-known carriers frequency in Nigeria (MTN, GLO, AITEL and ETISALAT. This paper went through two stages: Stage one: studying the GSM-system to find the best jamming technique, establishing the system design and selecting suitable components. Stage two: buying all the needed components, drawing the overall schematics, assembling the devices on a well known Veroboard, performing some measurements and finally testing the mobile jammer. The designed stage consist of voltage controlled oscillator, noise generator and Radio Frequency Amplification. MATBLAB Simulink 8.4 was used for the simulation of the frequency oscillator, On Running the simulation, and observing the output of the scope, a signal whose carrier repeatedly moves from 10.6927 to 10.9786 MHz was observed . We can see that the result was a signal at frequency RF covers the whole downlink The designed jammer was successful in jamming the four carriers in Nigeria operating on EDGE or 2G network

  7. Mobile Notes: Mobile Devices in Creative Discussions

    OpenAIRE

    Bollen, Lars; Juarez, Guillermo; Hoppe, Ulrich

    2006-01-01

    The trendy notion of "mobile learning" has different connotations: On the one hand, it can be understood as "learning on the move" - often referred to as "learning any time anywhere". Of course this interpretation relies on specific kinds of technological enabling, but the definition aims at the general setting of learning activities. Particularly, it includes informal learning settings (cf. [1]). A second interpretation sees mobile learning somewhat more pragmatically as learning with mobile...

  8. MOBILE TELECOMMUNICATIONS SERVICES AND MOBILE HEALTH DEVICES

    OpenAIRE

    Gheorghe Meghisan; Georgeta-Madalina Meghisan

    2015-01-01

    The purpose of this research paper is to identify the potential of mobile health devices with a positive impact on the public health care system from Romania. More people monitoring their health situation with the help of mobile health applications could lead to less money spent by the public health sector with treating more advanced diseases. Approach/ methodology. The analysis of the Romanian mobile telecommunications market and health situation of the population from Romania was based on s...

  9. Abrechnung mobiler Dienste im Mobile-Payment-Referenzmodell

    OpenAIRE

    Pousttchi, Key; Wiedemann, Dietmar Georg

    2005-01-01

    The purpose of the paper is to analyze mobile payments in the mobile commerce scenario. Therefore, we first classify the mobile payment in the mobile commerce scenario by explaining general offer models, charging concepts, and intermediaries. Second, we describe the mobile payment reference model, especially, the mobile payment reference organization model and different mobile payment standard types. Finally, we conclude our findings.

  10. Recent Advances in Subunit Vaccine Carriers.

    Science.gov (United States)

    Vartak, Abhishek; Sucheck, Steven J

    2016-01-01

    The lower immunogenicity of synthetic subunit antigens, compared to live attenuated vaccines, is being addressed with improved vaccine carriers. Recent reports indicate that the physio-chemical properties of these carriers can be altered to achieve optimal antigen presentation, endosomal escape, particle bio-distribution, and cellular trafficking. The carriers can be modified with various antigens and ligands for dendritic cells targeting. They can also be modified with adjuvants, either covalently or entrapped in the matrix, to improve cellular and humoral immune responses against the antigen. As a result, these multi-functional carrier systems are being explored for use in active immunotherapy against cancer and infectious diseases. Advancing technology, improved analytical methods, and use of computational methodology have also contributed to the development of subunit vaccine carriers. This review details recent breakthroughs in the design of nano-particulate vaccine carriers, including liposomes, polymeric nanoparticles, and inorganic nanoparticles. PMID:27104575

  11. Inert carriers for column extraction chromatography

    International Nuclear Information System (INIS)

    Inert carriers used in column extraction chromatography are reviewed. Such carriers are devided into two large groups: hydrophilic carriers which possess high surface energy and are well wetted only with strongly polar liquids (kieselguhrs, silica gels, glasses, cellulose, Al2O3) and water-repellent carriers which possess low surface energy and are well wetted with various organic solvents (polyethylene, polytetrafluorethylene polytrifluorochlorethylene). Properties of various carriers are presented: structure, chemical and radiation stability, adsorption properties, extracting agent capacity. The effect of structure and sizes of particles on the efficiency of chromatography columns is considered. Ways of immovable phase deposition on the carrier and the latter's regeneration. Peculiarities of column packing for preparative and continuous chromatography are discussed

  12. Mobile Scientific Calculator

    Directory of Open Access Journals (Sweden)

    Mohammed Abdulrahim Hamdi

    2012-02-01

    Full Text Available The mobile and wireless industry is entering an exciting time. Demand for mobile technology is growing at a tremendous rate. Corporations are deploying mobile applications that provide substantial business benefits, and consumers are readily adopting mobile data applications. We present scientific application for mobile phone in steps of software engineering project starting from data gathering, data analysis, designing, coding, packaging, testing and deploying, Mobile Scientific Calculator (MSC enable user to compute any mathematical operation by using this application in mobile phone without needing to use the calculator. Scientific calculator offers three keys the four mathematic operations, the four systems of digits and offering many of functions such as angles functions, power, factorial and other functions. Scientific calculator is suitable for many mobile phones which don t have scientific calculator in its applications, it provide simple design for dealing with its functions for all users. It operated on more than one mobile phone model.

  13. Global Telecommunications Services: Strategies of Major Carriers

    OpenAIRE

    Jerry Mccreary; William R. Boulton; Chetan Sankar

    1993-01-01

    The globalization of telecommunications markets is of primary concern for today’s large telecommunications carriers. International business telecommunications is growing at a rate twice that of domestic traffic. Multi-national customers with offices around the world are demanding integrated solutions to their telecommunications needs. As telecommunication carriers respond to these customers’ needs, the carriers are beginning to expand outside their national boundaries. This paper identifi...

  14. Free carrier absorption in quantum cascade structures

    OpenAIRE

    Carosella, F.; Ndebeka-Bandou, C.; Ferreira, R.; Dupont, E; K. Unterrainer; Strasser, G.; Wacker, Andreas; Bastard, G.

    2011-01-01

    We show that the free carrier absorption in Quantum Cascade Lasers is very small and radically different from the classical Drude result on account of the orthogonality between the direction of the carrier free motion and the electric field of the laser emission. A quantum mechanical calculation of the free carrier absorption and inter-subband oblique absorption induced by interface defects, coulombic impurities and optical phonon absorption/emission is presented for QCL's with a double quant...

  15. Secure quantum carriers for quantum state sharing

    OpenAIRE

    Karimipour, Vahid; Marvian, Milad

    2010-01-01

    We develop the concept of quantum carrier and show that messages can be uploaded and downloaded from this carrier and while in transit, these messages are hidden from external agents. We explain in detail the working of the quantum carrier for different communication tasks, including quantum key distribution, classical secret and quantum state sharing among a set of $n$ players according to general threshold schemes. The security of the protocol is discussed and it is shown that only the legi...

  16. Heterozygote advantage in Tay-Sachs carriers?

    OpenAIRE

    Spyropoulos, B; Moens, P B; Davidson, J.; Lowden, J. A.

    1981-01-01

    Chi-square analyses of new data as well as data previously reported by Myrianthopoulos have shown that grandparents of Tay-Sachs carriers die from proportionally the same causes as grandparents of noncarriers. It is unlikely that there is any advantage to being a Tay-Sachs carrier insofar as resistance to tuberculosis is concerned. Our results are further evidence to support Fraikor's claim that the high carrier frequency of the allele in Ashkenazi Jews is probably caused by a combination of ...

  17. Suppression of Compensating Native Defect Formation During Semiconductor Processing via Excess Carriers

    Energy Technology Data Exchange (ETDEWEB)

    Alberi, Kirstin; Scarpulla, M. A.

    2016-06-21

    In many semiconductors, compensating defects set doping limits, decrease carrier mobility, and reduce minority carrier lifetime thus limiting their utility in devices. Native defects are often responsible. Suppressing the concentrations of compensating defects during processing close to thermal equilibrium is difficult because formation enthalpies are lowered as the Fermi level moves towards the majority band edge. Excess carriers, introduced for example by photogeneration, modify the formation enthalpy of semiconductor defects and thus can be harnessed during crystal growth or annealing to suppress defect populations. Herein we develop a rigorous and general model for defect formation in the presence of steady-state excess carrier concentrations by combining the standard quasi-chemical formalism with a detailed-balance description that is applicable for any defect state in the bandgap. Considering the quasi-Fermi levels as chemical potentials, we demonstrate that increasing the minority carrier concentration increases the formation enthalpy for typical compensating centers, thus suppressing their formation. This effect is illustrated for the specific example of GaSb. While our treatment is generalized for excess carrier injection or generation in semiconductors by any means, we provide a set of guidelines for applying the concept in photoassisted physical vapor deposition.

  18. Impact of energy filtering and carrier localization on the thermoelectric properties of granular semiconductors

    International Nuclear Information System (INIS)

    Energy filtering has been widely considered as a suitable tool to increase the thermoelectric performances of several classes of materials. In its essence, energy filtering provides a way to increase the Seebeck coefficient by introducing a strongly energy-dependent scattering mechanism. Under certain conditions, however, potential barriers may lead to carrier localization, that may also affect the thermoelectric properties of a material. A model is proposed, actually showing that randomly distributed potential barriers (as those found, e.g., in polycrystalline films) may lead to the simultaneous occurrence of energy filtering and carrier localization. Localization is shown to cause a decrease of the actual carrier density that, along with the quantum tunneling of carriers, may result in an unexpected increase of the power factor with the doping level. The model is corroborated toward experimental data gathered by several authors on degenerate polycrystalline silicon and lead telluride. - Graphical abstract: In heavily doped semiconductors potential barriers may lead to both carrier energy filtering and localization. This may lead to an enhancement of the thermoelectric properties of the material, resulting in an unexpected increase of the power factor with the doping level. Highlights: ► Potential barriers are shown to lead to carrier localization in thermoelectric materials. ► Evidence is put forward of the formation of a mobility edge. ► Energy filtering and localization may explain the enhancement of power factor in degenerate semiconductors.

  19. Multi-carrier technologies for wireless communication

    CERN Document Server

    Nassar, Carl R; Wu, Zhiqiang; Wiegandt, David A; Zekavat, S Alireza; Shattil, Steve

    2006-01-01

    1. Introduction. 2. Overview of Multi-Carrier Technologies. 3. High-Performance High-Capacity MC-CDMA for Future Generations: The CI Approach. 4. High Performance, High Throughput TDMA via Multi-Carrier Implementations. 5. High-Performance, High-Capacity DS-CDMA via Multicarrier Implementation. 6. High-Performance, High-Throughput OFDM with Low PAPR via Carrier Interferometry Phase Coding. 7. The Marriage of Smart Antenna Arrays and Multi-Carrier Systems: Spatial Sweeping, Transmit Diversity, and Directionality. Index.

  20. Substrate dependence of Hall and Field-effect mobilities in few-layer MoS2 field-effect transistors

    Science.gov (United States)

    Chamlagain, Bhim; Perera, Meeghage; Chuang, Hsuen-Jen; Bowman, Arthur; Rijal, Upendra; Andrews, Kraig; Klesko, Joseph; Winter, Charles; Zhou, Zhixian

    In this work, we systematically study the Hall and field-effect mobilities of few-layer MoS2 FETs fabricated on different substrates. Hall bar devices were fabricated on SiO2 and hBN to directly measure carrier density. Standard four-probe transport measurement and Hall effect measurement were carried out for a wide temperature range to determine the carrier mobility and understand the scattering mechanisms. By comparing field-effect and Hall mobilities, we demonstrate that the intrinsic drift mobility of multiplayer MoS2 in the high carrier density metallic region is independent of substrate and sample thickness. While the optical-phonon scattering remains the dominant scattering mechanism in MoS2 devices on h-BN down to ~100 K, extrinsic scattering mechanisms start to degrade the carrier mobility of MoS2 on all other substrates below ~200 K. NSF Grant Number DMR-1308436.

  1. An Integrated Mobile Phone Payment System Based on 3G Network

    Directory of Open Access Journals (Sweden)

    Weihui Dai

    2011-08-01

    Full Text Available Along with globally approaching of the 3G era, the progress of mobile communication technology and the development of mobile terminal devices will rapidly promote the mobilization development of traditional E-commerce. In order to ensure it to achieve further development, secure, flexible and reliable mobile payment system is becoming more and more important. Compared with the payment pattern of ordinary commerce, there will be profound changes in the mobile payment, such as special payment channel, payment carrier and etc. After deep studying about previous payment methods and future 3G communication technology, this paper introduces a new mobile payment model by combining with IC chip, mobile phone and mobile internet, and then gives some improvement measures for current settlement mechanisms in the network transaction, which is entirely around payment channel, payment carrier, security authentication and other key issues in 3G environment. The real time processing of information flow, capital flow and logistics in mobile environment can be easily achieved, forming a complete and reliable business operation for mobile users, which can bring some great conveniences and profound influences for mobile payment industry.

  2. Charge Carrier Transport and Photogeneration in P3HT:PCBM Photovoltaic Blends

    KAUST Repository

    Laquai, Frederic

    2015-05-03

    This article reviews the charge transport and photogeneration in bulk-heterojunction solar cells made from blend films of regioregular poly(3-hexylthiophene) (RR-P3HT) and methano­fullerene (PCBM). The charge transport, specifically the hole mobility in the RR-P3HT phase of the polymer:fullerene photovoltaic blend, is dramatically affected by thermal annealing. The hole mobility increases more than three orders of magnitude and reaches a value of up to 2 × 10−4 cm2 V−1 s−1 after the thermal annealing process as a result of an improved semi-crystallinity of the film. This significant increase of the hole mobility balances the electron and hole mobilities in a photovoltaic blend in turn reducing space-charge formation, and this is the most important factor for the strong enhancement of the photovoltaic efficiency compared to an as cast, that is, non-annealed device. In fact, the balanced charge carrier mobility in RR-P3HT:PCBM blends in combination with a field- and temperature-independent charge carrier generation and greatly reduced non-geminate recombination explains the large quantum efficiencies mea­sured in P3HT:PCBM photovoltaic devices.

  3. Mobile Portal Implementation Strategy

    DEFF Research Database (Denmark)

    Gao, Ping; Damsgaard, Jan

    2005-01-01

    Mobile portal plays an important role in mobile commerce market. Current literature focuses on static analysis on the value chain of mobile portals. This article provides a dynamic perspective on mobile portal strategy. Drawing upon network economics, we describe mobile portal implementation...... as a fourphase process. In different phase, a portal provider has various challenges to overcome and adopt diverse strategies, and correspondingly the regulator has different foci. The conceptual framework proposed in this article offers a basis for further analyses on the market dynamics of mobile commerce...

  4. Head First Mobile Web

    CERN Document Server

    Gardner, Lyza; Grigsby, Jason

    2011-01-01

    Despite the huge number of mobile devices and apps in use today, your business still needs a website. You just need it to be mobile. Head First Mobile Web walks you through the process of making a conventional website work on a variety smartphones and tablets. Put your JavaScript, CSS media query, and HTML5 skills to work-then optimize your site to perform its best in the demanding mobile market. Along the way, you'll discover how to adapt your business strategy to target specific devices. Navigate the increasingly complex mobile landscapeTake both technical and strategic approaches to mobile

  5. Mobile Router Technology Development

    Science.gov (United States)

    Ivancic, William D.; Stewart, David H.; Bell, Terry L.; Kachmar, Brian A.; Shell, Dan; Leung, Kent

    2002-01-01

    Cisco Systems and NASA have been performing joint research on mobile routing technology under a NASA Space Act Agreement. Cisco developed mobile router technology and provided that technology to NASA for applications to aeronautic and space-based missions. NASA has performed stringent performance testing of the mobile router, including the interaction of routing and transport-level protocols. This paper describes mobile routing, the mobile router, and some key configuration parameters. In addition, the paper describes the mobile routing test network and test results documenting the performance of transport protocols in dynamic routing environments.

  6. 14 CFR 221.204 - Adoption of provisions of one carrier by another carrier.

    Science.gov (United States)

    2010-01-01

    ... TRANSPORTATION (AVIATION PROCEEDINGS) ECONOMIC REGULATIONS TARIFFS Electronically Filed Tariffs § 221.204... carrier, the effective and prospective fares of the adopted carrier shall be changed to reflect the...

  7. Exploring the Mobility of Mobile Phone Users

    CERN Document Server

    Csáji, Balázs Cs; Traag, V A; Delvenne, Jean-Charles; Huens, Etienne; Van Dooren, Paul; Smoreda, Zbigniew; Blondel, Vincent D

    2013-01-01

    Mobile phone datasets allow for the analysis of human behavior on an unprecedented scale. The social network, temporal dynamics and mobile behavior of mobile phone users have often been analyzed independently from each other using mobile phone datasets. In this article, we explore the connections between various features of human behavior extracted from a large mobile phone dataset. Our observations are based on the analysis of communication data of 100000 anonymized and randomly chosen individuals in a dataset of communications in Portugal. We show that clustering and principal component analysis allow for a significant dimension reduction with limited loss of information. The most important features are related to geographical location. In particular, we observe that most people spend most of their time at only a few locations. With the help of clustering methods, we then robustly identify home and office locations and compare the results with official census data. Finally, we analyze the geographic spread ...

  8. Properties and applications of high-mobility semiconducting nanotubes

    International Nuclear Information System (INIS)

    Experiments to determine the resistivity and charge-carrier mobility in semiconducting carbon nanotubes are reviewed. Electron transport experiments on long chemical-vapour-deposition-grown semiconducting carbon nanotubes are interpreted in terms of diffusive transport in a field-effect transistor. This allows for extraction of the field-effect and saturation mobilities for hole carriers, as well as an estimate of the intrinsic hole mobility of the nanotubes. The intrinsic mobility can exceed 100,000 cm2 V-1 s-1 at room temperature, which is greater than any other known semiconductor. Scanned-probe experiments show a low degree of disorder in chemical-vapour-deposition-grown semiconducting carbon nanotubes compared with laser-ablation produced nanotubes, and show conductivity and mean-free-path consistent with the high mobility values seen in transport experiments. The application of high-mobility semiconducting nanotubes to charge detection and memory is also reviewed; it is shown that single electronic charges may be detected with a semiconducting nanotube field-effect transistor at operating temperatures up to 200 K. (topical review)

  9. Mobile Phones on Campus

    Institute of Scientific and Technical Information of China (English)

    朴春宝

    2007-01-01

    After entering the 21st century, more and more people have mobile phones in China. At the end of 2002, there were 20 million mobile phone users. By the year 2005 the number has reached up to 30 million.

  10. Tandem mobile robot system

    Science.gov (United States)

    Buttz, James H.; Shirey, David L.; Hayward, David R.

    2003-01-01

    A robotic vehicle system for terrain navigation mobility provides a way to climb stairs, cross crevices, and navigate across difficult terrain by coupling two or more mobile robots with a coupling device and controlling the robots cooperatively in tandem.

  11. Ion mobility sensor system

    Science.gov (United States)

    Xu, Jun; Watson, David B.; Whitten, William B.

    2013-01-22

    An ion mobility sensor system including an ion mobility spectrometer and a differential mobility spectrometer coupled to the ion mobility spectrometer. The ion mobility spectrometer has a first chamber having first end and a second end extending along a first direction, and a first electrode system that generates a constant electric field parallel to the first direction. The differential mobility spectrometer includes a second chamber having a third end and a fourth end configured such that a fluid may flow in a second direction from the third end to the fourth end, and a second electrode system that generates an asymmetric electric field within an interior of the second chamber. Additionally, the ion mobility spectrometer and the differential mobility spectrometer form an interface region. Also, the first end and the third end are positioned facing one another so that the constant electric field enters the third end and overlaps the fluid flowing in the second direction.

  12. Mobile Multilayer IPsec protocol

    Directory of Open Access Journals (Sweden)

    T.Gayathri

    2009-08-01

    Full Text Available A mobile user moves around and switches between wireless cells, subnets and domains, it needs to maintain the session continuity. At the same time security of signaling and transport media should not be compromised. A multi-layer security framework involving user authentication, packet based encryption and access control mechanism can provide the desired level of security to the mobile users. Supporting streaming traffic in a mobile wireless Internet is faced with several challenges due to continuous handoff experienced by a mobile user. These challenges include dynamic binding, location management, quality of service and end-to-end security for signaling and transport. Mobile users will use heterogeneous radio access networking technologies. Mobile multilayer IPsec protocol (MML IPSec extends ML-IPSec to deal with mobility and make it suitable for wireless networks. MML-IPSec is integration of ML-IPSec and mobile IP.

  13. Mobile Informal Learning

    NARCIS (Netherlands)

    Glahn, Christian; Börner, Dirk

    2010-01-01

    Glahn, C., & Börner, D. (2009). Mobile Informal Learning. Presented at Mobile Learning in Context Symposium at the Open University of the Netherlands. September, 11, 2009, Heerlen, The Netherlands: Open University of the Netherlands.

  14. Test for mobility

    OpenAIRE

    Li Kheng

    2014-01-01

    Mobile application testing is a process by which application software developed for mobile devices is tested, in aspects as functionality, usability and consistency. These applications can be pre-installed or installed from distribution platforms for mobile software. Due mobile devices have witnessed of a phenomenal growth in recent years (a study by Yankee Group predicted to generate $ 4.2 billion in revenue for 2013 through 7000 million downloads of applications the U.S.), it is necesary te...

  15. PSiS Mobile

    OpenAIRE

    Anacleto, Ricardo; Luz, Nuno; Figueiredo, Lino

    2010-01-01

    In this paper, we present a state of the art on applications of mobile devices to support decision of a tourist running on a trip. We focus on two types of applications, tourism recommendation and tourism guide, making a brief description of the main characteristics of each one of them. We also refer the main problems encountered on the development of applications for mobile devices, and present PSiS (Personalized Sightseeing Tours Recommendation System) Mobile, our proposal to a mobile recom...

  16. Mobile internet protocol analysis

    OpenAIRE

    Brachfeld, Lawrence J.

    1999-01-01

    Mobile Internet Protocol (IP) is a proposed standard that builds on the current Internet Protocol by making the fact that a user is mobile transparent to applications and higher level protocols such as Transmission Control Protocol (TCP) and User Datagram Protocol (UDP). Mobile IP allows mobile computers to send and receive packets addressed with their home network IP address, regardless of the IP address of their current point of attachment on the Internet while maintaining any current conne...

  17. Fixed mobile convergence handbook

    CERN Document Server

    Ahson, Syed A

    2010-01-01

    From basic concepts to future directions, this handbook provides technical information on all aspects of fixed-mobile convergence (FMC). The book examines such topics as integrated management architecture, business trends and strategic implications for service providers, personal area networks, mobile controlled handover methods, SIP-based session mobility, and supervisory and notification aggregator service. Case studies are used to illustrate technical and systematic implementation of unified and rationalized internet access by fixed-mobile network convergence. The text examines the technolo

  18. Mobile social gaming

    OpenAIRE

    Coulton, Paul; Čopič Pucihar, Klen; Bamford, William

    2008-01-01

    After ten years of game design practices routed within traditional PC and console development aimed at hardcore gamers, the mobile games industry has embraced the realization that these have limited value for mobile, and new approaches need to be considered. In particular the greater utilization of social factors within games would embrace the social practices in which mobile phones often engage. Whilst this has led some to propose MMOGs for mobile, the behavior of players of these games sugg...

  19. Mobile connections : curator's statement.

    OpenAIRE

    Hemment, Drew

    2004-01-01

    The Mobile Connections exhibition at the Futuresonic 2004 festival explored how mobile and locative media reconfigure social, cultural and information space. It looked beyond computing in its current form, towards the social and cultural possibilities opened by a new generation of networked, location-aware media. It sought an art of mobile communications: asking, are there any forms of expression that are intrinsic or unique to mobile and locative media?

  20. Focus on personal mobility

    OpenAIRE

    Lucas Harms, Peter Jorritsma, Nelly Kalfs

    2011-01-01

    Focus on personal mobilityVarious important societal trends, including aging, immigration, individualization and re-urbanization, influence the mobility of Dutch people. In future, these trends will lead to further (yet slowing) growth in car use, to public transport being used less in rural regions and more in urban areas, and to bicycle use claiming a smaller share of total mobility. In 'Focus on personal mobility', the Kim Netherlands Institute for Transport Policy Analysis focuses on the ...

  1. Mobile Marketing in Japan

    OpenAIRE

    Noah H. N. Lynn; Paul D. Berger

    2014-01-01

    In this paper we describe the state of mobile marketing in Japan. We consider the various aspects of mobile marketing in Japan and what has led to the overwhelming adoption by Japanese youth, and to a degree Japanese society as a whole, of social media and associated activities. This growth of mobile marketing has dramatic, positive implications for marketing, in general, as well as for the sale of selected product classes. We also consider markers for suggesting what the future of mobile mar...

  2. Mobile Services Adoption Model

    OpenAIRE

    Abu Ghannam, Bashar

    2011-01-01

    This research presents an explanatory model for consumers' adoption of mobile services. This model uses the Unified Theory of Acceptance and Use of Technology presented by Venkatesh in 2003 as a baseline and integrates the Perceived Enjoyment, Mobile Affinity, Perceived Price of Service and the Frequency of Mobile Usage as to investigate the Attitude and the Intention to Use mobile services. The proposed model was empirically tested using data collected from a field survey where 1095 responde...

  3. Ion mobility spectrometry

    CERN Document Server

    Eiceman, GA

    2005-01-01

    Key Developments for Faster, More Precise Detection Capabilities Driven by the demand for the rapid and advanced detection of explosives, chemical and biological warfare agents, and narcotics, ion mobility spectrometry (IMS) undergone significant refinements in technology, computational capabilities, and understanding of the principles of gas phase ion chemistry and mobility. Beginning with a thorough discussion of the fundamental theories and physics of ion mobility, Ion Mobility Spectrometry, Second Edition describes the recent advances in instrumentation and newly

  4. Inert carrier drying and coating process

    International Nuclear Information System (INIS)

    An inert carrier process is described for drying radioactive (particularly low level) waste material and for incorporating the dry material into a binder matrix from which the dried material will not be leached. Experimental details, and examples of the carrier and binder materials, are given. (U.K.)

  5. Providing resilience for carrier ethernet multicast traffic

    DEFF Research Database (Denmark)

    Ruepp, Sarah Renée; Wessing, Henrik; Zhang, Jiang; Manolova, Anna Vasileva; Rasmussen, Anders; Dittmann, Lars; Berger, Michael Stübert

    2009-01-01

    This paper presents an overview of the Carrier Ethernet technology with specific focus on resilience. In particular, we detail how multicast traffic, which is essential for e.g. IPTV can be protected. We present Carrier Ethernet resilience methods for linear and ring networks and show by simulation...

  6. Towards 100 gigabit carrier ethernet transport networks

    DEFF Research Database (Denmark)

    Rasmussen, Anders; Zhang, Jiang; Yu, Hao;

    2010-01-01

    OAM functions, survivability and the increased bandwidth requirements of carrier class systems. This article provides an overview of PBB-TE and T-MPLS and demonstrates how IPTV services can be realized in the framework of Carrier Ethernet. In addition we provide a case study on performing bit error...

  7. Providing resilience for carrier ethernet multicast traffic

    DEFF Research Database (Denmark)

    Ruepp, Sarah Renée; Wessing, Henrik; Zhang, Jiang;

    2009-01-01

    This paper presents an overview of the Carrier Ethernet technology with specific focus on resilience. In particular, we detail how multicast traffic, which is essential for e.g. IPTV can be protected. We present Carrier Ethernet resilience methods for linear and ring networks and show by simulation...... that the availability of a multicast connection can be significantly increased by applying relevant resilience techniques....

  8. Mobile Student Information System

    Science.gov (United States)

    Asif, Muhammad; Krogstie, John

    2011-01-01

    Purpose: A mobile student information system (MSIS) based on mobile computing and context-aware application concepts can provide more user-centric information services to students. The purpose of this paper is to describe a system for providing relevant information to students on a mobile platform. Design/methodology/approach: The research…

  9. Mobile Collocated Interactions

    DEFF Research Database (Denmark)

    Lucero, Andrés; Clawson, James; Lyons, Kent;

    2015-01-01

    Mobile devices such as smartphones and tablets were originally conceived and have traditionally been utilized for individual use. Research on mobile collocated interactions has been looking at situations in which collocated users engage in collaborative activities using their mobile devices, thus...

  10. Selection of Carrier Waveforms for PWM Inverter

    Institute of Scientific and Technical Information of China (English)

    陈国呈; 屈克庆; 许春雨; 孙承波

    2003-01-01

    In this paper the influence of different carrier waveforms upon the output characteristics of PWM inverter is described in detail. When a triangular carrier waveform is used in hard-switching PWM inverters, harmonics exist in the neighborhood of the output frequency of the inverter output voltage and current due to the dead time. The triangular carrier waveform used in soft-switching PWM inverter will cause difficulties in controlling resonance-trigger time, higher loss in the resonant circuit, and less utilization of the DC bus voltage. If a sawtooth carrier is used in hard-switching PWM inverter, there will be severe distortion in the current waveform. When sawtooth carriers with alternate positive and negative slopes are used in soft-switching PWM inverters, the resonancetrigger time is easy to control, and distortion in the output voltage and current caused by the dead time will not appear.

  11. A charge carrier transport model for donor-acceptor blend layers

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, Janine, E-mail: janine.fischer@iapp.de; Widmer, Johannes; Koerner, Christian; Vandewal, Koen; Leo, Karl, E-mail: leo@iapp.de [Institut für Angewandte Photophysik, Technische Universität Dresden, 01062 Dresden (Germany); Kleemann, Hans [Novaled GmbH, Dresden (Germany); Tress, Wolfgang, E-mail: leo@iapp.de [Institut für Angewandte Photophysik, Technische Universität Dresden, 01062 Dresden (Germany); Laboratoire de Photonique et Interfaces, École polytechnique fédérale de Lausanne, 1015 Lausanne (Switzerland); Riede, Moritz [Institut für Angewandte Photophysik, Technische Universität Dresden, 01062 Dresden (Germany); Physics Department, University of Oxford, Oxford OX1 3PU (United Kingdom)

    2015-01-28

    Highly efficient organic solar cells typically comprise donor-acceptor blend layers facilitating effective splitting of excitons. However, the charge carrier mobility in the blends can be substantially smaller than in neat materials, hampering the device performance. Currently, available mobility models do not describe the transport in blend layers entirely. Here, we investigate hole transport in a model blend system consisting of the small molecule donor zinc phthalocyanine (ZnPc) and the acceptor fullerene C{sub 60} in different mixing ratios. The blend layer is sandwiched between p-doped organic injection layers, which prevent minority charge carrier injection and enable exploiting diffusion currents for the characterization of exponential tail states from a thickness variation of the blend layer using numerical drift-diffusion simulations. Trap-assisted recombination must be considered to correctly model the conductivity behavior of the devices, which are influenced by local electron currents in the active layer, even though the active layer is sandwiched in between p-doped contacts. We find that the density of deep tail states is largest in the devices with 1:1 mixing ratio (E{sub t} = 0.14 eV, N{sub t} = 1.2 × 10{sup 18 }cm{sup −3}) directing towards lattice disorder as the transport limiting process. A combined field and charge carrier density dependent mobility model are developed for this blend layer.

  12. A charge carrier transport model for donor-acceptor blend layers

    International Nuclear Information System (INIS)

    Highly efficient organic solar cells typically comprise donor-acceptor blend layers facilitating effective splitting of excitons. However, the charge carrier mobility in the blends can be substantially smaller than in neat materials, hampering the device performance. Currently, available mobility models do not describe the transport in blend layers entirely. Here, we investigate hole transport in a model blend system consisting of the small molecule donor zinc phthalocyanine (ZnPc) and the acceptor fullerene C60 in different mixing ratios. The blend layer is sandwiched between p-doped organic injection layers, which prevent minority charge carrier injection and enable exploiting diffusion currents for the characterization of exponential tail states from a thickness variation of the blend layer using numerical drift-diffusion simulations. Trap-assisted recombination must be considered to correctly model the conductivity behavior of the devices, which are influenced by local electron currents in the active layer, even though the active layer is sandwiched in between p-doped contacts. We find that the density of deep tail states is largest in the devices with 1:1 mixing ratio (Et = 0.14 eV, Nt = 1.2 × 1018 cm−3) directing towards lattice disorder as the transport limiting process. A combined field and charge carrier density dependent mobility model are developed for this blend layer

  13. MOBILE BUSINESS APPROACH BASED ON MOBILE AGENT

    Directory of Open Access Journals (Sweden)

    Ahmed Aloui

    2011-01-01

    Full Text Available Users today want the opportunity to make (or manage a businesses in anytime and anywhere via their mobile devices. This paper proposes the architecture with mobile agent for the mobile businesses (m-business. M-business appeared as the promising approach to drive the vague following one of electronic business (e-business. Most of the e-busines [9] applications uses the traditional model client/server in which a commercial operation requires generally a link of stable communication being established between the customer and the server, and the traditional approach client/server [8] constitutes an obstacle to the development of application of m-business. The proposed architecture introduces several advantages: in the first place, allow the consumers to manage their commercial business driven by types of mobile devices (phones, PDAs, etc. .... at any time and wherever. Secondly, minimize the waiting time of the customer, and the quantity of transferring information. Third, this architecture addresses the problem of time limited and expensive connection for mobile users. The Mobile agents will be used on a single level: research agent. Every research mobile agent will be used to visit the target server site of the application to collect the information’s for his client, which allows it to interact locally with a server, and so to reduce the traffic on the network by transmitting only the useful data.

  14. Distributed mobility management - framework & analysis

    NARCIS (Netherlands)

    Liebsch, M.; Seite, P.; Karagiannis, G.

    2013-01-01

    Mobile operators consider the distribution of mobility anchors to enable offloading some traffic from their core network. The Distributed Mobility Management (DMM) Working Group is investigating the impact of decentralized mobility management to existing protocol solutions, while taking into account

  15. Methanol as an energy carrier

    Energy Technology Data Exchange (ETDEWEB)

    Biedermann, P.; Grube, T.; Hoehlein, B. (eds.)

    2006-07-01

    For the future, a strongly growing energy demand is expected in the transport sector worldwide. Economically efficient oil production will run through a maximum in the next decade. Higher fuel prices and an environmentally desirable reduction of emissions will increase the pressure for reducing fuel consumption and emissions in road traffic. These criteria show the urgent necessity of structural changes in the fuel market. Due to its advantages concerning industrial-scale production, storage and global availability, methanol has the short- to medium-term potential for gaining increased significance as a substitution product in the energy market. Methanol can be produced both from fossil energy sources and from biomass or waste materials through the process steps of synthesis gas generation with subsequent methanol synthesis. Methanol has the potential to be used in an environmentally friendly manner in gasoline/methanol mixtures for flexible fuel vehicles with internal combustion engines and in diesel engines with pure methanol. Furthermore, it can be used in fuel cell vehicles with on-board hydrogen production in direct methanol fuel cell drives, and in stationary systems for electricity and heat generation as well as for hydrogen production. Finally, in portable applications it serves as an energy carrier for electric power generation. In this book, the processes for the production and use of methanol are presented and evaluated, markets and future options are discussed and issues of safety and environmental impacts are addressed by a team of well-known authors. (orig.)

  16. Optoelectronic characterization of carrier extraction in a hot carrier photovoltaic cell structure

    Science.gov (United States)

    Dimmock, James A. R.; Kauer, Matthias; Smith, Katherine; Liu, Huiyun; Stavrinou, Paul N.; Ekins-Daukes, Nicholas J.

    2016-07-01

    A hot carrier photovoltaic cell requires extraction of electrons on a timescale faster than they can lose energy to the lattice. We optically and optoelectronically characterize two resonant tunneling structures, showing their compatability with hot carrier photovoltaic operation, demonstrating structural and carrier extraction properties necessary for such a device. In particular we use time resolved and temperature dependent photoluminescence to determine extraction timescales and energy levels in the structures and demonstrate fast carrier extraction by tunneling. We also show that such devices are capable of extracting photo-generated electrons at high carrier densities, with an open circuit voltage in excess of 1 V.

  17. Effects of carrier-carrier scattering on population inversion in graphene under pulse photoexcitation

    Science.gov (United States)

    Satou, Akira; Ryzhii, Victor; Otsuji, Taiichi

    2015-01-01

    We study the carrier relaxation dynamics in intrinsic graphene after pulse photoexcitation and reveal effects of intraband carrier-carrier scattering on population inversion in the terahertz region, by conducting simulation based on the quasi-classical Boltzmann equation. It is demonstrated that by changing the dielectric constant of the surrounding materials the rate of carrier-carrier scattering can be controlled and the relaxation dynamics differs for cases with low and high dielectric constants. It is also found that the Pauli blocking of photogeneration in case of the pulse photoexcitation causes decrease in the photocarrier concentration and thus weakening of population inversion with higher dielectric constant.

  18. Charge carrier transport properties in layer structured hexagonal boron nitride

    Science.gov (United States)

    Doan, T. C.; Li, J.; Lin, J. Y.; Jiang, H. X.

    2014-10-01

    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.

  19. 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.

  20. Spectrum Reorganization and Bundling for Power Efficient Mobile Networks

    DEFF Research Database (Denmark)

    Micallef, Gilbert; Mogensen, Preben; Scheck, Hans-Otto

    2012-01-01

    still required for supporting legacy devices and providing wider network coverage. In order to facilitate and reduce the cost of rolling out a new network, mobile operators often reuse existing sites. Radio frequency modules in base station sites house power amplifiers, which are designed to operate...... can be reorganized within a single band, and have multiple carriers bundled together to fully exploit the capabilities of modern equipment. These modifications are applied on all network layers, maintaining the same number of carriers and baseband capacity. For the presented case, this results in the...

  1. Mobile Virtual Private Networking

    Science.gov (United States)

    Pulkkis, Göran; Grahn, Kaj; Mårtens, Mathias; Mattsson, Jonny

    Mobile Virtual Private Networking (VPN) solutions based on the Internet Security Protocol (IPSec), Transport Layer Security/Secure Socket Layer (SSL/TLS), Secure Shell (SSH), 3G/GPRS cellular networks, Mobile IP, and the presently experimental Host Identity Protocol (HIP) are described, compared and evaluated. Mobile VPN solutions based on HIP are recommended for future networking because of superior processing efficiency and network capacity demand features. Mobile VPN implementation issues associated with the IP protocol versions IPv4 and IPv6 are also evaluated. Mobile VPN implementation experiences are presented and discussed.

  2. Do we value mobility?

    OpenAIRE

    Amiel, Yoram; Bernasconi, Michele; Cowell, Frank; Dardanoni, Valentino

    2015-01-01

    Is there a trade-off between people's preference for income equality and income mobility? Testing for the existence of such a trade-off is difficult because mobility is a multifaceted concept. We analyse results from a questionnaire experiment based on simple precise concepts of income inequality and income mobility. We fnd no direct trade-off in preference between mobility and equality, but an indirect trade-off, applying when more income mobility can only be obtained at the expense of some ...

  3. Mobile intention recognition

    CERN Document Server

    Kiefer, Peter

    2011-01-01

    Mobile Intention Recognition addresses problems of practical relevance for mobile system engineers: how can we make mobile assistance systems more intelligent? How can we model and recognize patterns of human behavior which span more than a limited spatial context? This text provides an overview on plan and intention recognition, ranging from the late 1970s to very recent approaches. This overview is unique as it discusses approaches with respect to the specificities of mobile intention recognition. This book covers problems from research on mobile assistance systems using methods from artific

  4. Measuring Charge Carrier Diffusion in Coupled Colloidal Quantum Dot Solids

    KAUST Repository

    Zhitomirsky, David

    2013-06-25

    Colloidal quantum dots (CQDs) are attractive materials for inexpensive, room-temperature-, and solution-processed optoelectronic devices. A high carrier diffusion length is desirable for many CQD device applications. In this work we develop two new experimental methods to investigate charge carrier diffusion in coupled CQD solids under charge-neutral, i.e., undepleted, conditions. The methods take advantage of the quantum-size-effect tunability of our materials, utilizing a smaller-bandgap population of quantum dots as a reporter system. We develop analytical models of diffusion in 1D and 3D structures that allow direct extraction of diffusion length from convenient parametric plots and purely optical measurements. We measure several CQD solids fabricated using a number of distinct methods and having significantly different doping and surface ligand treatments. We find that CQD materials recently reported to achieve a certified power conversion efficiency of 7% with hybrid organic-inorganic passivation have a diffusion length of 80 ± 10 nm. The model further allows us to extract the lifetime, trap density, mobility, and diffusion coefficient independently in each material system. This work will facilitate further progress in extending the diffusion length, ultimately leading to high-quality CQD solid semiconducting materials and improved CQD optoelectronic devices, including CQD solar cells. © 2013 American Chemical Society.

  5. Analysis of Charge Carrier Transport in Organic Photovoltaic Active Layers

    Science.gov (United States)

    Han, Xu; Maroudas, Dimitrios

    2015-03-01

    We present a systematic analysis of charge carrier transport in organic photovoltaic (OPV) devices based on phenomenological, deterministic charge carrier transport models. The models describe free electron and hole transport, trapping, and detrapping, as well as geminate charge-pair dissociation and geminate and bimolecular recombination, self-consistently with Poisson's equation for the electric field in the active layer. We predict photocurrent evolution in devices with active layers of P3HT, P3HT/PMMA, and P3HT/PS, as well as P3HT/PCBM blends, and photocurrent-voltage (I-V) relations in these devices at steady state. Charge generation propensity, zero-field charge mobilities, and trapping, detrapping, and recombination rate coefficients are determined by fitting the modeling predictions to experimental measurements. We have analyzed effects of the active layer morphology for layers consisting of both pristine drop-cast films and of nanoparticle (NP) assemblies, as well as effects on device performance of insulating NP doping in conducting polymers and of specially designed interlayers placed between an electrode and the active layer. The model predictions provide valuable input toward synthesis of active layers with prescribed morphology that optimize OPV device performance.

  6. Dynamics of charge carriers on hexagonal nanoribbons with vacancy defects

    Science.gov (United States)

    Ferreira da Cunha, Wiliam; de Oliveira Neto, Pedro Henrique; Terai, Akira; Magela e Silva, Geraldo

    2016-07-01

    We develop a general model to investigate the dynamics of charge carriers in vacancy endowed honeycomb two-dimensional nanolattices. As a fundamental application, results concerning the influence of vacancies placed on different sites of semiconducting armchair graphene nanoribbons (AGNR) over the transport of polarons are presented. It is observed that the positioning of vacancies plays a major role over the scattering of the charge carriers, in the sense that their overall mobility is determined by where the defect is allocated. By considering different structural configurations of the system, the arising polaron can either move freely or be reflected. Therefore, our work provides a phenomenological understanding of the underlying mechanism responsible for the change of conductivity experienced by systems in which structural defects are present, a fact that has been reported for different nanostructures of the same symmetry. Because vacancies are one of the most common kinds of defects and are, in practice, unavoidable, the kind of description proposed in the present paper is crucial to correctly address transport and electronic properties in more realistic electronic devices based on two-dimensional nanolattices.

  7. Mobility Charters and Manifestos

    DEFF Research Database (Denmark)

    Jensen, Ole B.

    2010-01-01

    This paper explore a number of different cases of articulating notions of ‘correct’ mobility behavior and practice by looking into charters, manifestos and codes of mobility regulation. Within such discourses of ‘correct mobility’ more or less subtle expressions of power as well as normative and...... ethical positions on mobility prevail. Such ‘imagined correct mobility behavior’ are drawing on larger issues of societal change that need to be brought out in a critical analysis and discussion reflecting the attempts to control, design and orchestrate mobility patterns. The paper therefore argues within...... 2007, the English ‘Highway Code Booklets’ from the 1930’s, 40’s and 50’s, the ‘City Slow Charter’, the ‘New Urbanism Charter’ as attempts to codify and order mobility and mobile practices....

  8. Photoinduced Dedoping of Conducting Polymers: An Approach to Precise Control of the Carrier Concentration and Understanding Transport Properties.

    Science.gov (United States)

    Wei, Qingshuo; Mukaida, Masakazu; Kirihara, Kazuhiro; Naitoh, Yasuhisa; Ishida, Takao

    2016-01-27

    Exploring the various applications of conjugated polymers requires systematic studies of their physical properties as a function of the doping density, which, consequently, calls for precise control of their doping density. In this study, we report a novel solid-state photoinduced charge-transfer reaction that dedopes highly conductive polyelectrolyte complexes such as poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonate). Varying the UV-irradiation time of this material allows the carrier density inside the film to be precisely controlled over more than 3 orders of magnitude. We extract the carrier density, carrier mobility, and Seebeck coefficient at different doping levels to obtain a clear image of carrier-transport mechanisms. This approach not only leads to a better understanding of the physical properties of the conducting polymer but also is useful for developing applications requiring patterned, large-area conducting polymers. PMID:26734776

  9. Acoustostimulated change of electron mobility in n-CdxHg1-xTe crystals

    International Nuclear Information System (INIS)

    Electron mobility of n-CdxHg1-xTe crystals is investigated at a dynamic ultrasound loading. A mobility increases in the region of impurity conductivity (T 120 K) for all measured samples are observed. It is demonstrated that the main reason for the mobility increase in the region of impurity conductivity is down sizing of the macropotential in the crystal, and an increase of the scattering intensity on optical phonons results in a decrease of carrier's mobility in the region of intrinsic conductivity

  10. Mobile Communication, Public Participation and E-Governance in China

    DEFF Research Database (Denmark)

    Liu, Jun; Zhao, Hui

    2010-01-01

    and took various civic actions again them. A rare sense of participation in public affairs is fostered through the use of mobile communication technology. The government must figure out how to improve the effective and regular information exchange and feedback top down and bottom up to raise the awareness...... upon the developments of public participation, social inclusion and citizenship through the case study of Xiamen PX demonstration. In terms of local environmental activism, the Xiamen residents shared information with the help of wireless communication about the alleged misdeeds of party officials......China has become the biggest mobile communication carrier in the world since 2001. Advanced technologies create a communication revolution, and the individual, through the advent of mobile media, has become an active participant in this process. This study investigates the mobile phone’s impact...

  11. Photoconductivity of CdTe Nanocrystal-Based Thin Films. Te2- Ligands Lead To Charge Carrier Diffusion Lengths Over 2 Micrometers

    Energy Technology Data Exchange (ETDEWEB)

    Crisp, Ryan W. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Callahan, Rebecca [National Renewable Energy Lab. (NREL), Golden, CO (United States); Reid, Obadiah G. [Univ. of Colorado, Boulder, CO (United States); Dolzhnikov, Dmitriy S. [Univ. of Chicago, IL (United States); Talapin, Dmitri V. [Univ. of Chicago, IL (United States); Rumbles, Garry [National Renewable Energy Lab. (NREL), Golden, CO (United States); Luther, Joseph M. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Kopidakis, Nikos [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2015-11-16

    We report on photoconductivity of films of CdTe nanocrystals (NCs) using time-resolved microwave photoconductivity (TRMC). Spherical and tetrapodal CdTe NCs with tunable size-dependent properties are studied as a function of surface ligand (including inorganic molecular chalcogenide species) and annealing temperature. Relatively high carrier mobility is measured for films of sintered tetrapod NCs (4 cm2/(V s)). Our TRMC findings show that Te2- capped CdTe NCs show a marked improvement in carrier mobility (11 cm2/(V s)), indicating that NC surface termination can be altered to play a crucial role in charge-carrier mobility even after the NC solids are sintered into bulk films.

  12. 49 CFR 369.2 - Classification of carriers-motor carriers of property, household goods carriers, and dual...

    Science.gov (United States)

    2010-10-01

    ... operating revenues after applying the revenue deflator formula shown in Note A. (3) When a business combination occurs such as a merger, reorganization, or consolidation, the surviving carrier shall...

  13. Non-dispersive carrier transport in molecularly doped polymers and the convection-diffusion equation

    Science.gov (United States)

    Tyutnev, A. P.; Parris, P. E.; Saenko, V. S.

    2015-08-01

    We reinvestigate the applicability of the concept of trap-free carrier transport in molecularly doped polymers and the possibility of realistically describing time-of-flight (TOF) current transients in these materials using the classical convection-diffusion equation (CDE). The problem is treated as rigorously as possible using boundary conditions appropriate to conventional time of flight experiments. Two types of pulsed carrier generation are considered. In addition to the traditional case of surface excitation, we also consider the case where carrier generation is spatially uniform. In our analysis, the front electrode is treated as a reflecting boundary, while the counter electrode is assumed to act either as a neutral contact (not disturbing the current flow) or as an absorbing boundary at which the carrier concentration vanishes. As expected, at low fields transient currents exhibit unusual behavior, as diffusion currents overwhelm drift currents to such an extent that it becomes impossible to determine transit times (and hence, carrier mobilities). At high fields, computed transients are more like those typically observed, with well-defined plateaus and sharp transit times. Careful analysis, however, reveals that the non-dispersive picture, and predictions of the CDE contradict both experiment and existing disorder-based theories in important ways, and that the CDE should be applied rather cautiously, and even then only for engineering purposes.

  14. High capacity carrier ethernet transport networks

    DEFF Research Database (Denmark)

    Rasmussen, Anders; Zhang, Jiang; Yu, Hao; Fu, Rong; Ruepp, Sarah Renée; Wessing, Henrik; Berger, Michael Stübert

    2009-01-01

    technology, making the use of Ethernet as a convergence layer for Next Generation Networks a distinct possibility. Triple Play services, in particular IPTV, are expected to be a main drivers for carrier Ethernet, however, a number of challenges must be addressed including QoS enabled control plane, enhanced...... OAM functions, survivability and the increased bandwidth requirements of carrier class systems. This article provides an overview of PBB-TE and T-MPLS and demonstrates how IPTV services can be realized in the framework of Carrier Ethernet. In addition we provide a case study on performing bit error...

  15. High capacity carrier ethernet transport networks

    DEFF Research Database (Denmark)

    Rasmussen, Anders; Zhang, Jiang; Yu, Hao;

    2009-01-01

    Ethernet as a transport technology has, up to now, lacked the features such as network layer architecture, customer separation and manageability that carriers require for wide-scale deployment. However, with the advent of PBB-TE and T-MPLS, it is now possible to use Ethernet as a transport...... OAM functions, survivability and the increased bandwidth requirements of carrier class systems. This article provides an overview of PBB-TE and T-MPLS and demonstrates how IPTV services can be realized in the framework of Carrier Ethernet. In addition we provide a case study on performing bit error...

  16. ISRAEL’S NATIONAL WATER CARRIER

    OpenAIRE

    Nathan Cohen

    2008-01-01

    The National Water Carrier of Israel (Ha Movil Ha' Artzi). It is the main water project of Israel and its main task is to transfer water from the rainy north to the center and to the arid south. The National Water Carrier connects the Sea of Galilee with Israel's water system. The original goal was to provide irrigation water to Negev. Today 80% of the water is utilized for Israel's domestic consumption. Most of the water works in Israel are combined with the National Water Carrier for about...

  17. Carrier scattering in metals and semiconductors

    CERN Document Server

    Gantmakher, VF

    1987-01-01

    The transport properties of solids, as well as the many optical phenomena in them are determined by the scattering of current carriers. ``Carrier Scattering in Metals and Semiconductors'' elucidates the state of the art in the research on the scattering mechanisms for current carriers in metals and semiconductors and describes experiments in which these mechanisms are most dramatically manifested.The selection and organization of the material is in a form to prepare the reader to reason independently and to deal just as independently with available theoretical results and experimental

  18. Carrier transport and localization in a one-dimensional electronic system over liquid helium

    Science.gov (United States)

    Gladchenko, S. P.; Nikolaenko, V. A.; Kovdrya, Yu. Z.; Sokolov, S. S.

    2001-01-01

    The carrier mobility in a nearly one-dimensional electronic system over liquid helium is measured. One-dimensional conducting channels are created by using the curvature of the surface of liquid helium covering a profiled dielectric substrate and applying a clamping electric field, which holds the electrons on the bottom of the liquid troughs. Measurements are made in a temperature interval of 0.5-1.6 K at linear densities in the range (0.5-2.5)×104 cm-1 at a generator voltage of 2-200 mV. It is shown that for a clean substrate the mobility of the electrons is governed by their interaction with helium atoms in the vapor and with ripplons; the results of the measurements are in satisfactory agreement with a theoretical calculation that assumes no localization. It is found that for substrates carrying a charge or having defects on the surface, the electron mobility decreases in comparison with the value for a clean substrate, and at temperatures T<1 K is either practically independent of temperature or decreases slightly as the temperature is lowered. It is observed that the frequency of the plasma waves propagating in the system of conducting channels decreases as the electron mobility decreases. The observed effects can be explained by localization in the one-dimensional electronic system in a random potential and the diffusive motion of the carriers in hops from one localized state to another.

  19. Mobile VLE vs. Mobile PLE: How Informal is Mobile Learning?

    OpenAIRE

    Chen, Wen-Pin; Millard, David; Wills, Gary

    2008-01-01

    Mobile Learning Systems are often described as supporting informal learning; as such they are a good fit to the idea of Personal Learning Environments (PLEs), software systems that users choose and tailor to fit their own learning preferences. This paper explores the question of whether existing m-learning research is more in the spirit of PLEs or Virtual Learning Environments (VLEs). To do this we survey the mobile learning systems presented at M-Learn 2007 in order to see if they might be r...

  20. Drift of charge carriers in crystalline organic semiconductors.

    Science.gov (United States)

    Dong, Jingjuan; Si, Wei; Wu, Chang-Qin

    2016-04-14

    We investigate the direct-current response of crystalline organic semiconductors in the presence of finite external electric fields by the quantum-classical Ehrenfest dynamics complemented with instantaneous decoherence corrections (IDC). The IDC is carried out in the real-space representation with the energy-dependent reweighing factors to account for both intermolecular decoherence and energy relaxation by which conduction occurs. In this way, both the diffusion and drift motion of charge carriers are described in a unified framework. Based on an off-diagonal electron-phonon coupling model for pentacene, we find that the drift velocity initially increases with the electric field and then decreases at higher fields due to the Wannier-Stark localization, and a negative electric-field dependence of mobility is observed. The Einstein relation, which is a manifestation of the fluctuation-dissipation theorem, is found to be restored in electric fields up to ∼10(5) V/cm for a wide temperature region studied. Furthermore, we show that the incorporated decoherence and energy relaxation could explain the large discrepancy between the mobilities calculated by the Ehrenfest dynamics and the full quantum methods, which proves the effectiveness of our approach to take back these missing processes. PMID:27083750

  1. Drift of charge carriers in crystalline organic semiconductors

    Science.gov (United States)

    Dong, Jingjuan; Si, Wei; Wu, Chang-Qin

    2016-04-01

    We investigate the direct-current response of crystalline organic semiconductors in the presence of finite external electric fields by the quantum-classical Ehrenfest dynamics complemented with instantaneous decoherence corrections (IDC). The IDC is carried out in the real-space representation with the energy-dependent reweighing factors to account for both intermolecular decoherence and energy relaxation by which conduction occurs. In this way, both the diffusion and drift motion of charge carriers are described in a unified framework. Based on an off-diagonal electron-phonon coupling model for pentacene, we find that the drift velocity initially increases with the electric field and then decreases at higher fields due to the Wannier-Stark localization, and a negative electric-field dependence of mobility is observed. The Einstein relation, which is a manifestation of the fluctuation-dissipation theorem, is found to be restored in electric fields up to ˜105 V/cm for a wide temperature region studied. Furthermore, we show that the incorporated decoherence and energy relaxation could explain the large discrepancy between the mobilities calculated by the Ehrenfest dynamics and the full quantum methods, which proves the effectiveness of our approach to take back these missing processes.

  2. Mobile healthcare informatics.

    Science.gov (United States)

    Siau, Keng; Shen, Zixing

    2006-06-01

    Advances in wireless technology give pace to the rapid development of mobile applications. The coming mobile revolution will bring dramatic and fundamental changes to our daily life. It will influence the way we live, the way we do things, and the way we take care of our health. For the healthcare industry, mobile applications provide a new frontier in offering better care and services to patients, and a more flexible and mobile way of communicating with suppliers and patients. Mobile applications will provide important real time data for patients, physicians, insurers, and suppliers. In addition, it will revolutionalize the way information is managed in the healthcare industry and redefine the doctor - patient communication. This paper discusses different aspects of mobile healthcare. Specifically, it presents mobile applications in healthcare, and discusses possible challenges facing the development of mobile applications. Obstacles in developing mobile healthcare applications include mobile device limitations, wireless networking problems, infrastructure constraints, security concerns, and user distrust. Research issues in resolving or alleviating these problems are also discussed in the paper. PMID:16777784

  3. Social mobility and fertility.

    Science.gov (United States)

    Kasarda, J D; Billy, J O

    1985-01-01

    This review examines 4 possible causal links between social mobility and fertility: 1) fertility affects social mobility; 2) social mobility affects fertility; 3) fertility and social mobility simultaneously affect each other; and 4) social mobility and fertility are unrelated. Due to the lack of systematic theory guiding the research, conceptualizations and measures of social mobility and fertility vary markedly from study to study, leading to inconsistent findings. The review focuses on theoretical perspectives underpinning the research, causal operators proposed to interpret observed associations, and analytical methods used. The selectivity perspective is based on the contention that a family must be small in order to rise on the social scale. This has found little support, however. In fact, studies suggest that children induce slightly higher levels of status achievement and family responsibilities may stimulate the energy and ambition of some so that they achieve more than they would have done without a family. Most studies have concerned the hypothesis that social mobility affects fertility. 4 theoretical perspectives have emerged: status enhancement; relative economic status; social isolation; and stress and disorientation. At any time in a couple's reproductive life cycle the decision or actual experience of either social mobility or fertility may influence the decision or actual experience of the other variable. Mobility-fertility research has defined an individual's or couple's position in terms of income, education, or occupation with occupation used most often as a single index of social class and indexes of social mobility developed by comparing persons' changes in occupational position. A common theme in much of the research literature is that the existence of an effect of social mobility on fertility depends on the societal conditions of a given population. Most studies through the mid-60s used a common measurement method to assess whether a

  4. Geo-based Mobility Control for Mobile Traffic Simulators

    OpenAIRE

    Dahlström, Patrik

    2013-01-01

    Most mobile traffic simulators of today depend on the user to supply the mobility behavior of the simulated UEs. This becomes a problem when certain wanted mobility characteristics are to be tested, since the user have to go trough a trial-and-error procedure to come up with the proper mobility behavior. This thesis presents two approaches to mobility control, where the aim is to control UE mobility based on certain mobility characteristics supplied by the end user. The first approach introdu...

  5. Hybrid Perovskites for Photovoltaics: Charge-Carrier Recombination, Diffusion, and Radiative Efficiencies.

    Science.gov (United States)

    Johnston, Michael B; Herz, Laura M

    2016-01-19

    Photovoltaic (PV) devices that harvest the energy provided by the sun have great potential as renewable energy sources, yet uptake has been hampered by the increased cost of solar electricity compared with fossil fuels. Hybrid metal halide perovskites have recently emerged as low-cost active materials in PV cells with power conversion efficiencies now exceeding 20%. Rapid progress has been achieved over only a few years through improvements in materials processing and device design. In addition, hybrid perovskites appear to be good light emitters under certain conditions, raising the prospect of applications in low-cost light-emitting diodes and lasers. Further optimization of such hybrid perovskite devices now needs to be supported by a better understanding of how light is converted into electrical currents and vice versa. This Account provides an overview of charge-carrier recombination and mobility mechanisms encountered in such materials. Optical-pump-terahertz-probe (OPTP) photoconductivity spectroscopy is an ideal tool here, because it allows the dynamics of mobile charge carriers inside the perovskite to be monitored following excitation with a short laser pulse whose photon energy falls into the range of the solar spectrum. We first review our insights gained from transient OPTP and photoluminescence spectroscopy on the mechanisms dominating charge-carrier recombination in these materials. We discuss that mono-molecular charge-recombination predominantly originates from trapping of charges, with trap depths being relatively shallow (tens of millielectronvolts) for hybrid lead iodide perovskites. Bimolecular recombination arises from direct band-to-band electron-hole recombination and is found to be in significant violation of the simple Langevin model. Auger recombination exhibits links with electronic band structure, in accordance with its requirement for energy and momentum conservation for all charges involved. We further discuss charge-carrier mobility

  6. Mobility activation in thermally deposited CdSe thin films

    Indian Academy of Sciences (India)

    Kangkan Sarmah; Ranjan Sarma

    2009-08-01

    Effect of illumination on mobility has been studied from the photocurrent decay characteristics of thermally evaporated CdSe thin films deposited on suitably cleaned glass substrate held at elevated substrate temperatures. The study indicates that the mobilities of the carriers of different trap levels are activated due to the energy of incident illumination, which results in the existence of two distinct trap levels. In each trap depth the energy of the trap increases linearly. It infers that there is a linear distribution of traps of different energies below the conduction band.

  7. Why is CDMA the solution for mobile satellite communication

    Science.gov (United States)

    Gilhousen, Klein S.; Jacobs, Irwin M.; Padovani, Roberto; Weaver, Lindsay A.

    1989-01-01

    It is demonstrated that spread spectrum Code Division Multiple Access (CDMA) systems provide an economically superior solution to satellite mobile communications by increasing the system maximum capacity with respect to single channel per carrier Frequency Division Multiple Access (FDMA) systems. Following the comparative analysis of CDMA and FDMA systems, the design of a model that was developed to test the feasibility of the approach and the performance of a spread spectrum system in a mobile environment. Results of extensive computer simulations as well as laboratory and field tests results are presented.

  8. Mobile Technology Waiting for the 3G Rush

    Institute of Scientific and Technical Information of China (English)

    HAYET SELLAMI

    2006-01-01

    @@ China is potentially the biggest third generation (3G) mobile market in the world, and everyone is eager to grab a piece of the pie. Foreign carriers are still not allowed to apply for licences since China's decision regarding licensing and adoption of 3G mobile services is still pending, but the waiting list is long. Both Chinese officials and industry executives have stated that they want 3G in place in time for the August 2008 Olympic Games held in Beijing. This tight deadline leaves no room for failure.

  9. Clusters of dislocations in a carrier wave

    International Nuclear Information System (INIS)

    Clusters of point dislocations (wave vortices) may be present within an otherwise perfect plane scalar wave, a carrier wave in two dimensions, which may be evanescent. The question arises: is it possible to deduce the orientation of the distant undisturbed carrier wave purely from local information about the cluster itself? For groups of two and four dislocations in a carrier wave, this may be done by using no other information than the local phase map or the individual positions of the singularities. The maximum number possible in a cluster with a carrier wave is 4 and the total strength (topological charge) of a cluster is always zero or ± 2. The study includes an examination of degenerate dislocations of strength zero or ± 1

  10. The Kinetics of Carrier Transport Inhibition

    DEFF Research Database (Denmark)

    Rosenberg, T.; Wilbrandt, Robert Walter

    1962-01-01

    The kinetical treatment of enzymatic carrier transports as given in previous communications has been extended to conditions of inhibition. Various possible types of inhibitors have been considered differing in the site of attack (enzyme or carrier), in the mode of action (competing with the...... substrate for the enzyme or the carrier or for both, competing with the carrier for the enzyme, or non-competitive) and in the ability of penetrating the membrane. Experiments are reported on the inhibition of glucose and fructose transport across the human red cell membrane by phlorizine, phloretine and......, with the result that a certain asymmetry of inhibition (stronger inhibition of exit than of entrance) is to be expected. This asymmetry was termed “first order asymmetry”. In experiments with each of the three inhibitors an asymmetry of inhibition in the expected direction was observed which however...

  11. Physician Fee Schedule Carrier Specific Files

    Data.gov (United States)

    U.S. Department of Health & Human Services — The Centers for Medicare and Medicaid Services (CMS) has condensed all 56 Physician Fee Schedule (PFS) carrier specific pricing files into one zip file. It is...

  12. Intraoral radiation carrier for edentulous patients

    International Nuclear Information System (INIS)

    The principles of fabricating an intraoral radioactive carrier have been described to treat malignant diseases of the oral cavity. The prosthesis provides consistent direction and fixation of the radioactive source into the same location

  13. Intraoral radiation carrier for edentulous patients

    Energy Technology Data Exchange (ETDEWEB)

    Sela, M.; Taicher, S.

    1983-12-01

    The principles of fabricating an intraoral radioactive carrier have been described to treat malignant diseases of the oral cavity. The prosthesis provides consistent direction and fixation of the radioactive source into the same location.

  14. Embodied Cultures of Mobilities

    DEFF Research Database (Denmark)

    Jensen, Ole B.

    2010-01-01

    particular emphasis is put on how mobilities produce and re-produce norms, meanings and cultures in relation to the Everyday life perspective. By looking into walking, running, cycling, driving and mass transit mobilities different modes of embodied mobility is identified. The theoretical framework is based...... material artifacts. The paper target the complex relationship between the moving, sensing body and the material and built environment of infrastructures and mobility modes in order to explore what norms, and meanings, and everyday life mobility cultures are being produced and re-produced in this process. A...... and interaction (Lynch). The argument is thus that understanding embodied cultures of mobilities from the vantage point of this paper lend is self to new interpretations, explorations and understandings of what it means to move within and between other social agents in particular material and physical...

  15. Making Everyday Mobility

    DEFF Research Database (Denmark)

    Wind, Simon

    Based upon a qualitative PhD study of 11 families everyday mobility, this paper inquiries into the everyday mobility of families with children in the Greater Copenhagen Area and the role mobility plays in contributing to coping in the families’ everyday life. Drawing on Mobilities theory (Jensen...... 2013; Urry 2007) and family theory (Holdsworth 2013; Morgan 2011), it is argued that family mobility is far from only an instrumental phenomenon, displacing family members back and forth between activities and doings, but also a type of family practice (Morgan, 2011) carrying social and emotional...... practices. Specific heterogeneous configurations in mobility practices facilitate instrumental movement of family members, but can also engender care, quality time of togetherness, recreational and productive in-betweens, as well as sensorial and emotional experiences through the orchestration of affective...

  16. CERN Mobility Survey

    CERN Multimedia

    GS Department

    2011-01-01

    The Institute of Shipping and Transport of the University of the Aegean and the National Technical University of Athens are partners with CERN in a study of mobility patterns between and within the CERN sites and to that effect have realized a mobility survey dedicated to the CERN community.         The study aims to understand: How you presently get around the CERN sites; What problems you encounter regarding mobility; What your needs are; What improvements you’d like to see; What measures you would like to see implemented most. The replies we receive will enable us to define a general policy promoting the diversity of mobility at CERN and to establish and quantify the strategic actions to be implemented for both the short and medium term. The objectives of the transport mobility plans are to: Facilitate mobility within and between the CERN sites by identifying adequate solutions in response to individual ...

  17. Understanding pastoral mobility

    DEFF Research Database (Denmark)

    Adriansen, Hanne Kirstine

    2008-01-01

    Based on a case study from Sahelian Senegal, this paper analyses how various actors perceive the importance of pastoral mobility and presents issues of importance for understanding the use of mobility among Fulani of Ferlo. One knowledge system is a scientific one, the 'new rangeland paradigm......'. According to this, pastoral mobility is a means to balance variability in dryland resources; hence, 'nature' is the point of departure. Another knowledge system is local pastoral knowledge. For the pastoralists, the well-being of their animals is the point of departure and mobility is used to ensure that...... the livestock are in good condition. The paper shows that it is important to distinguish between mobility of pastoralists and of their herd; even though the pastoralists of northern Senegal have become semi-sedentary, their herds are still quite mobile. The pastoralists are willing to move around...

  18. Understanding pastoral mobility

    DEFF Research Database (Denmark)

    Adriansen, Hanne Kirstine

    2008-01-01

    Based on a case study from Sahelian Senegal, this paper analyses how various actors perceive the importance of pastoral mobility and presents issues of importance for understanding the use of mobility among Fulani of Ferlo. One knowledge system is a scientific one, the 'new rangeland paradigm......'. According to this, pastoral mobility is a means to balance variability in dryland resources; hence, 'nature' is the point of departure. Another knowledge system is local pastoral knowledge. For the pastoralists, the well-being of their animals is the point of departure and mobility is used to ensure that...... within a small territory, which they consider their place, but are unwilling to employ large-scale mobility themselves. Mobility is not of importance for their ethnic identity and some use paid herders to care for their livestock. By looking at both knowledge systems, we achieve a better understanding of...

  19. Protection switching for carrier ethernet multicast

    DEFF Research Database (Denmark)

    Ruepp, Sarah Renée; Wessing, Henrik; Berger, Michael Stübert

    2010-01-01

    This paper addresses network survivability for IPTV multicast transport in Carrier Ethernet networks. The impact of link failures is investigated and suggestions for intelligent multicast resilience schemes are proposed. In particular, functions of the multicast tree are integrated with the Carrier...... recovery path length, recovery time, number of branch nodes and operational complexity. The integrated approach therefore shows significant potential to increase the QoE for IPTV users in case of network failures and recovery actions....

  20. Airport Congestion When Carriers Have Market Power

    OpenAIRE

    Brueckner, Jan K.

    2002-01-01

    This paper analyzes airport congestion when carriers are nonatomistic, showing how the results of the road-pricing literature are modified when the economic agents causing congestion have market power. The analysis shows that when an airport is dominated by a monopolist, congestion is fully internalized, yielding no role for congestion pricing under monopoly conditions. Under a Cournot oligopoly, however, carriers are shown to internalize only the congestion they impose on themselves. A toll ...

  1. Evaluating multicast resilience in carrier ethernet

    DEFF Research Database (Denmark)

    Ruepp, Sarah Renée; Wessing, Henrik; Zhang, Jiang;

    2010-01-01

    This paper gives an overview of the Carrier Ethernet technology with specific focus on resilience. In particular, we show how multicast traffic, which is essential for IPTV can be protected. We detail the ackground for resilience mechanisms and their control and e present Carrier Ethernet...... resilience methods for linear nd ring networks. By simulation we show that the vailability of a multicast connection can be significantly increased by applying protection methods....

  2. Preparation and application of magnetic microsphere carriers

    Institute of Scientific and Technical Information of China (English)

    ZHANG Bo; XING Jianmin; LIU Huizhou

    2007-01-01

    Magnetic microsphere carriers have received considerable attention,primarily because of their wide applications in the fields of biomedicine and bioengineering.In this paper,preparation methods,surface modification and application of magnetic carriers are reviewed.Emphasis will be placed on recent biological and biomedical developments and trends such as enzyme immobilization,cell isolation,protein purification,target drugs and DNA separation.

  3. Hot carrier solar cell absorbers: investigation of carrier cooling properties of candidate materials

    Science.gov (United States)

    Conibeer, G.; Shrestha, Santosh; Huang, Shujuan; Patterson, Robert; Xia, Hongze; Feng, Yu; Zhang, Pengfei; Gupta, Neeti; Smyth, Suntrana; Liao, Yuanxun; Lin, Shu; Wang, Pei; Dai, Xi; Chung, Simon; Yang, Jianfeng; Zhang, Yi

    2015-09-01

    The hot carrier cell aims to extract the electrical energy from photo-generated carriers before they thermalize to the band edges. Hence it can potentially achieve a high current and a high voltage and hence very high efficiencies up to 65% under 1 sun and 86% under maximum concentration. To slow the rate of carrier thermalisation is very challenging, but modification of the phonon energies and the use of nanostructures are both promising ways to achieve some of the required slowing of carrier cooling. A number of materials and structures are being investigated with these properties and test structures are being fabricated. Initial measurements indicate slowed carrier cooling in III-Vs with large phonon band gaps and in multiple quantum wells. It is expected that soon proof of concept of hot carrier devices will pave the way for their development to fully functioning high efficiency solar cells.

  4. Mobile Learning Project Report

    OpenAIRE

    Folley, Susan; Jabbar, Abdul

    2010-01-01

    Mobile learning is not a new concept, learning whilst on the move or away from formal educational settings has been happening a long time with the use of books, journal articles, television, radio etc. However what is new is the vast array of devices now available to access learning and to take advantage of being mobile but still being able to capture information and share, collaborate and upload it to a worldwide audience. Mobile learning (mlearning) is a growing area of pedagogic res...

  5. Mobile Exergaming Heuristics

    OpenAIRE

    Monk, Monika Patrice

    2014-01-01

    An alarming number of adolescents experience obesity and related health issues, in part because of a lack of exercise. Increased mobile technology availability can have negative effects on amount of exercise, but they can have positive effects as well. Leveraging mobile technology to encourage and motivate exercise has potential to decrease unhealthy lifestyles, especially among young people. Mobile exergaming is an emerging field that has the potential to motivate users to exercise while als...

  6. Mobile Cranes Models Review

    OpenAIRE

    Škaloud, Martin

    2011-01-01

    The thesis deals with mobile cranes with a lifting capacity of 50 tonnes. The introduction describes the basic concepts related to these machines. Followed by a general cranes overview. This thesis focuses on a brief description of wheeled and tracked mobile cranes. It describes the undercarriage of the wheeled cranes and undercarriage of the tracked crane and crawler crane with it’s basic elements. After that is described the structure of the upper rotating wheel and track mobile truck crane...

  7. Crossword solving mobile application

    OpenAIRE

    Pencelj, Andraž

    2013-01-01

    The thesis describes development of crossword solving mobile application with PhoneGap framework. The emphasis is on application development for Android platform. Thesis describes only application which runs on mobile devices without server-side part. First part of thesis describes crosswords and their history. It also describes technologies which were used. Emphasis is on describing PhoneGap framework and mobile web browsers. PhoneGap framework is used to develop native applications for m...

  8. Inequality and Mobility

    OpenAIRE

    John Hassler; José Vicente Rodríguez Mora; Joseph Zeira

    2003-01-01

    We use a general equilibrium OLG model to analyse the relation between intergenerational social mobility and wage inequality. We show that the correlation between mobility and inequality depends on which factor caused the change in inequality. The model can thus help discriminate between different competing explanations of the recent rise in US wage inequality. Under reasonable assumptions, skill-biased technical change tends to increase upward mobility, thereby causing a positive correlation...

  9. Inequality and Mobility

    OpenAIRE

    Rodriguez Mora, Sevi; Hassler, John; Zeira, Joseph

    2007-01-01

    We use a general equilibrium OLG model to analyse the relation between intergenerational social mobility and wage inequality. We show that the correlation between mobility and inequality depends on which factor caused the change in inequality. The model can thus help discriminate between different competing explanations of the recent rise in US wage inequality. Under reasonable assumptions, skill-biased technical change tends to increase upward mobility, thereby causing a positive correlation...

  10. Mobile computing for radiology.

    Science.gov (United States)

    Auffermann, William F; Chetlen, Alison L; Sharma, Arjun; Colucci, Andrew T; DeQuesada, Ivan M; Grajo, Joseph R; Kung, Justin W; Loehfelm, Thomas W; Sherry, Steven J

    2013-12-01

    The rapid advances in mobile computing technology have the potential to change the way radiology and medicine as a whole are practiced. Several mobile computing advances have not yet found application to the practice of radiology, while others have already been applied to radiology but are not in widespread clinical use. This review addresses several areas where radiology and medicine in general may benefit from adoption of the latest mobile computing technologies and speculates on potential future applications. PMID:24200475

  11. Mobile learning in medicine

    Science.gov (United States)

    Serkan Güllüoüǧlu, Sabri

    2013-03-01

    This paper outlines the main infrastructure for implicating mobile learning in medicine and present a sample mobile learning application for medical learning within the framework of mobile learning systems. Mobile technology is developing nowadays. In this case it will be useful to develop different learning environments using these innovations in internet based distance education. M-learning makes the most of being on location, providing immediate access, being connected, and acknowledges learning that occurs beyond formal learning settings, in places such as the workplace, home, and outdoors. Central to m-learning is the principle that it is the learner who is mobile rather than the device used to deliver m learning. The integration of mobile technologies into training has made learning more accessible and portable. Mobile technologies make it possible for a learner to have access to a computer and subsequently learning material and activities; at any time and in any place. Mobile devices can include: mobile phone, personal digital assistants (PDAs), personal digital media players (eg iPods, MP3 players), portable digital media players, portable digital multimedia players. Mobile learning (m-learning) is particularly important in medical education, and the major users of mobile devices are in the field of medicine. The contexts and environment in which learning occurs necessitates m-learning. Medical students are placed in hospital/clinical settings very early in training and require access to course information and to record and reflect on their experiences while on the move. As a result of this paper, this paper strives to compare and contrast mobile learning with normal learning in medicine from various perspectives and give insights and advises into the essential characteristics of both for sustaining medical education.

  12. Mobile Trillium Engine

    OpenAIRE

    Ali, Muhammad Ahmed

    2013-01-01

    Mobile trillium engine development, integration and deployment in clustered environment“The air transport industry has a constantly growing mobile workforce and a complex, dynamic workflow that requires workers to access and act on the real time information. Rapid mobilization and automation of the key workflow process will allow air transport industry to reduce business cost, better management and improved customer services.” [1]The aim of this thesis is to develop a backend system that inte...

  13. Perancangan Dashboard Mobil Pedesaan Multiguna

    OpenAIRE

    Nurul Madinah; I Made Londen Batan

    2013-01-01

    Mobil GEA yang merupakan mobil nasional akan dikembangkan menjadi mobil pedesaan multiguna. Salah satu bagian dalam mobil GEA yang menjadi perhatian adalah dashboard. Selama ini dashboard mobil GEA diproduksi secara manual, yaitu menggunakan proses wet lay-up dengan bahan komposit. Rencana ke depan produksi mobil pedesaan multiguna adalah produksi massa. Untuk memenuhi kebutuhan tersebut dirancang proses cetakan injeksi plastik (injection molding) untuk pembuatan dashboard mobil pedesaan mult...

  14. Mobility decline in old age

    DEFF Research Database (Denmark)

    Rantakokko, Merja; Mänty, Minna Regina; Rantanen, Taina

    2013-01-01

    Mobility is important for community independence. With increasing age, underlying pathologies, genetic vulnerabilities, physiological and sensory impairments, and environmental barriers increase the risk for mobility decline. Understanding how mobility declines is paramount to finding ways to pro...... promote mobility in old age.......Mobility is important for community independence. With increasing age, underlying pathologies, genetic vulnerabilities, physiological and sensory impairments, and environmental barriers increase the risk for mobility decline. Understanding how mobility declines is paramount to finding ways to...

  15. Radio Science Measurements with Suppressed Carrier

    Science.gov (United States)

    Asmar, Sami; Divsalar, Dariush; Oudrhiri, Kamal

    2013-01-01

    Radio Science started when it became apparent with early Solar missions that occultations by planetary atmospheres would affect the quality of radio communications. Since then the atmospheric properties and other aspects of planetary science, solar science, and fundamental physics were studied by scientists. Radio Science data was always extracted from a received pure residual carrier (without data modulation). For some missions, it is very desirable to obtain Radio Science data from a suppressed carrier modulation. In this paper we propose a method to extract Radio Science data when a coded suppressed carrier modulation is used in deep space communications. Type of modulation can be BPSK, QPSK, OQPSK, MPSK or even GMSK. However we concentrate mostly on BPSK modulation. The proposed method for suppressed carrier simply tries to wipe out data that acts as an interference for Radio Science measurements. In order to measure the estimation errors in amplitude and phase of the Radio Science data we use Cramer-Rao bound (CRB). The CRB for the suppressed carrier modulation with non-ideal data wiping is then compared with residual carrier modulation under the same noise condition. The method of derivation of CRB for non-ideal data wiping is an innovative method that presented here. Some numerical results are provided for coded system.

  16. Exploring the mobility of mobile phone users

    Science.gov (United States)

    Csáji, Balázs Cs.; Browet, Arnaud; Traag, V. A.; Delvenne, Jean-Charles; Huens, Etienne; Van Dooren, Paul; Smoreda, Zbigniew; Blondel, Vincent D.

    2013-03-01

    Mobile phone datasets allow for the analysis of human behavior on an unprecedented scale. The social network, temporal dynamics and mobile behavior of mobile phone users have often been analyzed independently from each other using mobile phone datasets. In this article, we explore the connections between various features of human behavior extracted from a large mobile phone dataset. Our observations are based on the analysis of communication data of 100,000 anonymized and randomly chosen individuals in a dataset of communications in Portugal. We show that clustering and principal component analysis allow for a significant dimension reduction with limited loss of information. The most important features are related to geographical location. In particular, we observe that most people spend most of their time at only a few locations. With the help of clustering methods, we then robustly identify home and office locations and compare the results with official census data. Finally, we analyze the geographic spread of users’ frequent locations and show that commuting distances can be reasonably well explained by a gravity model.

  17. Trust in Mobile Commerce

    OpenAIRE

    Kounelis, Ioannis; Loeschner, Jan

    2012-01-01

    This paper describes how a citizen, in our case a user of a mobile phone, is confronted with several aspects of trust when he/she uses different mobile commercial objects in a digital world. In particular, the topic of m-commerce and how a client mitigates trust all the way from his/her mobile device to the merchant is dealt with. To assess the trust chain, especially in respect to privacy and data protection, objects (for example a voucher) are used to model the mobile commerce domain.

  18. Programming the Mobile Web

    CERN Document Server

    Firtman, Maximiliano

    2010-01-01

    Today's market for mobile apps goes beyond the iPhone to include BlackBerry, Nokia, Windows Phone, and smartphones powered by Android, webOS, and other platforms. If you're an experienced web developer, this book shows you how to build a standard app core that you can extend to work with specific devices. You'll learn the particulars and pitfalls of building mobile apps with HTML, CSS, and other standard web tools. You'll also explore platform variations, finicky mobile browsers, Ajax design patterns for mobile, and much more. Before you know it, you'll be able to create mashups using Web 2.

  19. Test for mobility

    Directory of Open Access Journals (Sweden)

    Li Kheng

    2014-06-01

    Full Text Available Mobile application testing is a process by which application software developed for mobile devices is tested, in aspects as functionality, usability and consistency. These applications can be pre-installed or installed from distribution platforms for mobile software. Due mobile devices have witnessed of a phenomenal growth in recent years (a study by Yankee Group predicted to generate $ 4.2 billion in revenue for 2013 through 7000 million downloads of applications the U.S., it is necesary test engineers increasingly specialize. In this article are described the types of applications, the challenges of testing, and its automation.

  20. Mobile sentiment analysis

    OpenAIRE

    Chambers, L.; Tromp, E.; Pechenizkiy, M.; M. Gaber

    2012-01-01

    Mobile devices play a significant part in a user’s communication methods and much data that they read and write is received and sent via mobile phones, for instance SMS messages, e-mails, Twitter tweets and social media networking feeds. One of the main goals is to make people aware of how much negative and positive content they read and write via their mobile phones. Existing sentiment analysis applications perform sentiment analysis on downloaded data from mobile phones or use an applicatio...

  1. Mobile Test Capabilities

    Data.gov (United States)

    Federal Laboratory Consortium — The Electrical Power Mobile Test capabilities are utilized to conduct electrical power quality testing on aircraft and helicopters. This capability allows that the...

  2. Mobile computing handbook

    CERN Document Server

    Ilyas, Mohammad

    2004-01-01

    INTRODUCTION AND APPLICATIONS OF MOBILE COMPUTING Wearable Computing,A. Smailagic and D.P. Siewiorek Developing Mobile Applications: A Lime Primer,G.P. Picco, A.L. Murphy, and G.-C. Roman Pervasive Application Development: Approaches and Pitfalls,G. Banavar, N. Cohen, and D. Soroker ISAM, Joining Context-Awareness and Mobility to Building Pervasive Applications,I. Augustin, A. Corrêa Yamin, J.L. Victória Barbosa, L. Cavalheiro da Silva, R. Araújo Real, G. Frainer, G.G. Honrich Cavalheiro, and C.F. Resin Geyer Integrating Mobile Wireless Devices into the Computational Grid,T. Phan, L. Huan

  3. Doctors going mobile.

    Science.gov (United States)

    Romano, Ron; Baum, Neil

    2014-01-01

    Having a Web page and a blog site are the minimum requirements for an Internet presence in the new millennium. However, a Web page that loads on a personal computer or a laptop will be ineffective on a mobile or cellular phone. Today, with more existing and potential patients having access to cellular technology, it is necessary to reconfigure the appearance of your Web site that appears on a mobile phone. This article discusses mobile computing and suggestions for improving the appearance of your Web site on a mobile or cellular phone. PMID:25807610

  4. Secure Mobile Identities

    OpenAIRE

    Chandrasekaran, Varun; Amjad, Fareeha; Sharma, Ashlesh; Subramanian, Lakshminarayanan

    2016-01-01

    The unique identities of every mobile user (phone number,IMSI) and device (IMEI) are far from secure and are increasingly vulnerable to a variety of network-level threats. The exceedingly high reliance on the weak SIM authentication layer does not present any notion of end-to-end security for mobile users. We propose the design and implementation of Secure Mobile Identities (SMI), a repetitive key-exchange protocol that uses this weak SIM authentication as a foundation to enable mobile users ...

  5. Guest Editorial ~ Mobile Learning

    Directory of Open Access Journals (Sweden)

    Mohamed Ally

    2007-06-01

    Full Text Available This special IRRODL issue on mobile learning is timely because of the proliferation of mobile technology in society, globalization, and the need to re-examine how learning materials are designed and delivered for the new generation of learners. In today’s world, people are on the move and are demanding access to learning materials and information anytime and anywhere. At the same time, there is increasing use of mobile technology in different sectors of society to meet the needs of people on the move. In business, there is increasing use of mobile technologies for individuals to conduct their business anywhere and anytime. In healthcare, medical staff are using mobile technologies to access just-in-time information and to enter information in real time. People working in the field away from the central office use mobile technologies to access information and to communicate with other workers. Also, younger generations of learners are using mobile technologies for entertainment and socialization. These learners are using mobile devices to access information and multimedia materials and to communicate with friends. These new generations of learners do not see technology as something foreign. They readily accept technology and consider technology to be part of their lives. Moreover, the use of mobile technology is a 21st Century skill that students and workers must have to function in society.

  6. Disability and mobile Internet

    OpenAIRE

    Goggin, Gerard

    2015-01-01

    As the World Wide Web turns 25, it is an appropriate time to ask: where are we are now with disability and the Internet? A good place to look is in the burgeoning area of Internet and mobile technology. Accordingly, this paper explores the issues and prospect for disability and mobile Internet. It provides a brief history of the entwined nature of the rise of disability and the Internet, discusses the emergence of mobile Internets, and then turns to a discussion of mobile Web accessibility. I...

  7. Cooperative Mobile Web Browsing

    DEFF Research Database (Denmark)

    Perrucci, GP; Fitzek, FHP; Zhang, Qi;

    2009-01-01

    This paper advocates a novel approach for mobile web browsing based on cooperation among wireless devices within close proximity operating in a cellular environment. In the actual state of the art, mobile phones can access the web using different cellular technologies. However, the supported data......-range links can then be used for cooperative mobile web browsing. By implementing the cooperative web browsing on commercial mobile phones, it will be shown that better performance is achieved in terms of increased data rate and therefore reduced access times, resulting in a significantly enhanced web...

  8. Practical mobile forensics

    CERN Document Server

    Bommisetty, Satish; Mahalik, Heather

    2014-01-01

    The book is an easy-to-follow guide with clear instructions on various mobile forensic techniques. The chapters and the topics within are structured for a smooth learning curve, which will swiftly empower you to master mobile forensics. If you are a budding forensic analyst, consultant, engineer, or a forensic professional wanting to expand your skillset, this is the book for you. The book will also be beneficial to those with an interest in mobile forensics or wanting to find data lost on mobile devices. It will be helpful to be familiar with forensics in general but no prior experience is re

  9. Monte Carlo Studies of Charge Transport Below the Mobility Edge

    OpenAIRE

    Jakobsson, Mattias

    2012-01-01

    Charge transport below the mobility edge, where the charge carriers are hopping between localized electronic states, is the dominant charge transport mechanism in a wide range of disordered materials. This type of incoherent charge transport is fundamentally different from the coherent charge transport in ordered crystalline materials. With the advent of organic electronics, where small organic molecules or polymers replace traditional inorganic semiconductors, the interest for this type of h...

  10. Terahertz wafer-scale mobility mapping of graphene on insulating substrates without a gate

    DEFF Research Database (Denmark)

    Buron, Jonas Due; Mackenzie, David M. A.; Petersen, Dirch Hjorth;

    2015-01-01

    spectroscopy. sigma(dc) and tau(SC) are directly extracted from Drude model fits to terahertz conductance spectra obtained in each pixel of 10 x 10 cm(2) maps with a 400 mu m step size. sigma(dc)- and tau(SC)-maps are translated into mu(drift) and N-S maps through Boltzmann transport theory for graphene charge......We demonstrate wafer-scale, non-contact mapping of essential carrier transport parameters, carrier mobility (mu(drift)), carrier density (N-S), DC sheet conductance (sigma(dc)), and carrier scattering time (tau(SC)) in CVD graphene, using spatially resolved terahertz time-domain conductance...... carriers and these parameters are directly compared to van der Pauw device measurements on the same wafer. The technique is compatible with all substrate materials that exhibit a reasonably low absorption coefficient for terahertz radiation. This includes many materials used for transferring CVD graphene...

  11. Predictors of Social Mobilization Speed

    CERN Document Server

    Alstott, Jeff; Velu, Chander

    2013-01-01

    Mobilization across social networks is becoming increasingly influential, but little is known about what traits of individuals and their relationships affect their speed of mobilization between them. We ran a global social mobilization contest and recorded personal traits of the participants and those they mobilized. We examined how those traits influenced the speed of mobilization. Individuals mobilized faster when they heard about the contest directly from the contest organization, and decreased in speed when hearing from less personal source types (e.g. family vs. media). Mobilization was faster when the mobilizer and the mobilized heard about the contest through the same source type, and slower when both individuals were in different countries. Females mobilized other females faster than males mobilized other males. Mobilization was faster with young recruiters and old recruits, and slower with old recruiters and young recruits. These findings suggest ways to optimize the speed of social mobilization.

  12. Central role of electronic temperature for photoelectron charge and spin mobilities in p+-GaAs

    International Nuclear Information System (INIS)

    The charge and spin mobilities of minority photoelectrons in p+-GaAs are determined by monitoring the effect of an electric field on the spatial profiles of the luminescence and of its polarization. By using electric fields to increase the photoelectron temperature Te without significantly changing the hole or lattice temperatures, the charge and spin mobilities are shown to be principally dependent on Te. For Te > 70 K, both the charge and spin mobilities vary as Te−1.3, while at lower temperatures this changes to an even more rapid Te−4.3 law. This finding suggests that current theoretical models based on degeneracy of majority carriers cannot fully explain the observed temperature dependence of minority carrier mobility

  13. Mobilizing community energy

    International Nuclear Information System (INIS)

    What explains the galvanising of communities to participate actively in energy projects? How do groups mobilize to overcome the often formidable barriers highlighted in the existing literature? Drawing on original qualitative research of 100 community energy groups in Scotland, including six in-depth case studies, we explain how effective mobilization occurs and the political dynamics surrounding such mobilization. To capture these dynamics, we adapt theories offered by literature on social movements, with a particular focus on resource mobilization theories. Applying our adapted framework, we identify two particular sets of resources shaping community energy mobilization: (i) structural resources, which refer to the broad political context structuring and constraining opportunities for community energy mobilization; and (ii) symbolic resources—less tangible resources used to galvanise participants. We investigate to what extent our case study groups were able to draw upon and exploit these resources. We find that structural resources can either facilitate or hinder mobilization; what matters is how state resources are exploited and constraints mitigated. The use of symbolic resources was highly effective in aiding mobilization. Each of the groups examined – despite their considerable variation – effectively exploited symbolic resources such as shared identity or desire for strong, self reliant communities. - Highlights: ► Explains how/why community energy groups mobilize and the political dynamics surrounding it. ► Draws on original qualitative research of 100 community energy groups in Scotland. ► Identifies two particular sets of resources (structural and symbolic) and their importance. ► Explains how these resources shape community energy mobilization in Scotland. ► Provides an original application of resource mobilization theory to the field of energy studies.

  14. Differential Analysis of the Nasal Microbiome of Pig Carriers or Non-Carriers of Staphylococcus aureus.

    Science.gov (United States)

    Espinosa-Gongora, Carmen; Larsen, Niels; Schønning, Kristian; Fredholm, Merete; Guardabassi, Luca

    2016-01-01

    Staphylococcus aureus is presently regarded as an emerging zoonotic agent due to the spread of specific methicillin-resistant S. aureus (MRSA) clones in pig farms. Studying the microbiota can be useful for the identification of bacteria that antagonize such opportunistic veterinary and zoonotic pathogen in animal carriers. The aim of this study was to determine whether the nasal microbiome of pig S. aureus carriers differs from that of non-carriers. The V3-V5 region of the 16S rRNA gene was sequenced from nasal swabs of 44 S. aureus carriers and 56 non-carriers using the 454 GS FLX titanium system. Carriers and non-carriers were selected on the basis of quantitative longitudinal data on S. aureus carriage in 600 pigs sampled at 20 Danish herds included in two previous studies in Denmark. Raw sequences were analysed with the BION meta package and the resulting abundance matrix was analysed using the DESeq2 package in R to identify operational taxonomic units (OTUs) with differential abundance between S. aureus carriers and non-carriers. Twenty OTUs were significantly associated to non-carriers, including species with known probiotic potential and antimicrobial effect such as lactic acid-producing isolates described among Leuconostoc spp. and some members of the Lachnospiraceae family, which is known for butyrate production. Further 5 OTUs were significantly associated to carriage, including known pathogenic bacteria such as Pasteurella multocida and Klebsiella spp. Our results show that the nasal microbiome of pigs that are not colonized with S. aureus harbours several species/taxa that are significantly less abundant in pig carriers, suggesting that the nasal microbiota may play a role in the individual predisposition to S. aureus nasal carriage in pigs. Further research is warranted to isolate these bacteria and assess their possible antagonistic effect on S. aureus for the pursuit of new strategies to control MRSA in pig farming. PMID:27509169

  15. Differential Analysis of the Nasal Microbiome of Pig Carriers or Non-Carriers of Staphylococcus aureus

    Science.gov (United States)

    Espinosa-Gongora, Carmen; Larsen, Niels; Schønning, Kristian; Fredholm, Merete; Guardabassi, Luca

    2016-01-01

    Staphylococcus aureus is presently regarded as an emerging zoonotic agent due to the spread of specific methicillin-resistant S. aureus (MRSA) clones in pig farms. Studying the microbiota can be useful for the identification of bacteria that antagonize such opportunistic veterinary and zoonotic pathogen in animal carriers. The aim of this study was to determine whether the nasal microbiome of pig S. aureus carriers differs from that of non-carriers. The V3-V5 region of the 16S rRNA gene was sequenced from nasal swabs of 44 S. aureus carriers and 56 non-carriers using the 454 GS FLX titanium system. Carriers and non-carriers were selected on the basis of quantitative longitudinal data on S. aureus carriage in 600 pigs sampled at 20 Danish herds included in two previous studies in Denmark. Raw sequences were analysed with the BION meta package and the resulting abundance matrix was analysed using the DESeq2 package in R to identify operational taxonomic units (OTUs) with differential abundance between S. aureus carriers and non-carriers. Twenty OTUs were significantly associated to non-carriers, including species with known probiotic potential and antimicrobial effect such as lactic acid-producing isolates described among Leuconostoc spp. and some members of the Lachnospiraceae family, which is known for butyrate production. Further 5 OTUs were significantly associated to carriage, including known pathogenic bacteria such as Pasteurella multocida and Klebsiella spp. Our results show that the nasal microbiome of pigs that are not colonized with S. aureus harbours several species/taxa that are significantly less abundant in pig carriers, suggesting that the nasal microbiota may play a role in the individual predisposition to S. aureus nasal carriage in pigs. Further research is warranted to isolate these bacteria and assess their possible antagonistic effect on S. aureus for the pursuit of new strategies to control MRSA in pig farming. PMID:27509169

  16. Increasing mobile radiography productivity.

    Science.gov (United States)

    Wong, Edward; Lung, Ngan Tsz; Ng, Kris; Jeor, Patrick

    2013-01-01

    Mobile radiography using computed radiography (CR) cassettes is a common equipment combination with a workflow bottleneck limited by location of CR readers. Advent of direct digital radiography (DDR) mobile x-ray machines removes this limitation by immediate image review and quality control. Through the use of key performance indicators (KPIs), the increase in efficiency can be quantified. PMID:23986937

  17. Global Mobile Communication System

    OpenAIRE

    ECT Team, Purdue

    2007-01-01

    The Global Mobile Communications System is a satellite-based, wireless personal communications network designed to permit any type of telephone transmission -- voice, data, fax, paging -- to reach its destination anywhere on earth, at any time. It is bringing a new dimension of capability to the commercial, rural and mobile sectors by providing universal, portable service.

  18. Security for Mobility

    DEFF Research Database (Denmark)

    Nielson, Hanne Riis; Nielson, Flemming; Buchholtz, Mikael

    2004-01-01

    We show how to use static analysis to provide information about security issues related to mobility. First the syntax and semantics of Mobile Ambients is reviewed and we show how to obtain a so-called 0CFA analysis that can be implemented in polynomial time. Next we consider discretionary access...

  19. Mobile banking in Asia

    OpenAIRE

    Anne Ho

    2010-01-01

    Technology has transformed the banking industry with the introduction of mobile banking services that offer unprecedented convenience and accessibility to customers. This Asia Focus report describes the various approaches to mobile banking in Asia, and examines how particular countries have addressed regulatory issues.

  20. Staging interrail mobilities

    DEFF Research Database (Denmark)

    Jensen, Martin Trandberg; Gyimóthy, Szilvia; Jensen, Ole B.

    2016-01-01

    This article applies the multiscalar ‘staging mobilities’ framework from the emergent subfield of mobilities design to analyse an enduring European rail travel phenomenon, interrail. This discussion extends and contributes to tourism mobilities research. Second, the article enriches previous stud...

  1. Utopias of Mobilities

    DEFF Research Database (Denmark)

    Jensen, Ole B.; Freudendal-Pedersen, Malene

    2012-01-01

    Contemporary global challenges to the distribution and organization of mobilities require new ways of envisioning and imagining to bring forward the discussion about new visions and thus policies of future mobilities. This chapter explores the imaginary visioning by using earlier utopian thoughts...

  2. Proxemic Mobile Collocated Interactions

    DEFF Research Database (Denmark)

    Porcheron, Martin; Lucero, Andrés; Quigley, Aaron;

    2016-01-01

    Recent research on mobile collocated interactions has been looking at situations in which collocated users engage in collaborative activities using their mobile devices. However, existing practices fail to fully account for the culturally-dependent spatial relationships between people and their d...

  3. Telemedicine by mobile communication

    OpenAIRE

    Shimizu, K.

    1999-01-01

    We have proposed some techniques for mobile telemedicine and have verified their practical feasibility in experiments. This article presents technical considerations required to realize a practical mobile telemedicine system, techniques developed for multiple medical data transmission, and the satisfactory results of their applications to telemedicine in moving vehicles

  4. Mobility Management in Denmark

    DEFF Research Database (Denmark)

    Guasco, Clement Nicolas

    2012-01-01

    people fulfil their mobility needs so that they rely less on their cars and start using alternatives such as bicycles and public transport. This article analyses the possibility to use businesses as vectors for introducing Mobility Management within social practices in Denmark in the light of the recent...

  5. Mobile-first Bootstrap

    CERN Document Server

    Magno, Alexandre

    2013-01-01

    A practical, step-by-step tutorial on developing websites for mobile using Bootstrap.This book is for anyone who wants to get acquainted with the new features available in Bootstrap 3 and who wants to develop websites with the mobile-first feature of Bootstrap. The reader should have a basic knowledge of Bootstrap as a frontend framework.

  6. Wireless mobile Internet security

    CERN Document Server

    Rhee, Man Young

    2013-01-01

      The mobile industry for wireless cellular services has grown at a rapid pace over the past decade. Similarly, Internet service technology has also made dramatic growth through the World Wide Web with a wire line infrastructure. Realization for complete wired/wireless mobile Internet technologies will become the future objectives for convergence of these technologies thr

  7. Mastering Mobile Security

    Science.gov (United States)

    Panettieri, Joseph C.

    2007-01-01

    Without proper security, mobile devices are easy targets for worms, viruses, and so-called robot ("bot") networks. Hackers increasingly use bot networks to launch massive attacks against eCommerce websites--potentially targeting one's online tuition payment or fundraising/financial development systems. How can one defend his mobile systems against…

  8. Designing for mobile interaction

    DEFF Research Database (Denmark)

    Nazzi, Elena

    2009-01-01

    The theme of this PhD project is designing for mobile interaction with devices and services, for the accessing, making, and sharing of information, taking into account the dynamic physical and social settings that embrace this interaction. To narrow down this theme, the whole project focuses on the...... exploitation of social interaction --- in particular among senior citizens --- to enhance and support mobile interaction....

  9. Mobile Learning Anytime, Anywhere

    Science.gov (United States)

    Hlodan, Oksana

    2010-01-01

    Some educational institutions are taking the leap to mobile learning (m-learning) by giving out free iPods. For example, Abilene Christian University gave iPods or iPhones to freshman students and developed 15 Web applications specifically for the mobile devices. The iPod is not the only ubiquitous m-learning device. Any technology that connects…

  10. Security for Mobility

    DEFF Research Database (Denmark)

    Nielson, Hanne Riis; Nielson, Flemming; Buchholtz, Mikael

    2002-01-01

    We show how to use static analysis to provide information about security issues related to mobility. First the syntax and semantics of Mobile Ambients is reviewed and we show how to obtain a so-called 0CFA analysis that can be implemented in polynomial time. Next we consider discretionary access...

  11. Mobile Informal Learning

    NARCIS (Netherlands)

    Börner, Dirk; Glahn, Christian; Specht, Marcus

    2009-01-01

    Börner, D., Glahn, C., & Specht, M. (2009). Mobile Informal Learning. Presentation for the Education in the Wild: contextual and location-based mobile learning in action workshop at the STELLAR Alpine Rendez-Vous 2009. November, 30-December, 3, 2009, Garmisch-Partenkirchen, Germany.

  12. Understanding Mobile Apps

    Science.gov (United States)

    ... Related Items Tips for Using Public Wi-Fi Networks Computer Security Kids and Mobile Phones If you have ... Free" Security Scans Computer Security Disposing of Old Computers Disposing of Your Mobile ... Your Wireless Network Tech Support Scams Tips for Using Public Wi- ...

  13. Mobile Apps for Librarians

    Science.gov (United States)

    Power, June L.

    2013-01-01

    In an increasing mobile environment, library and reading-related activities often take place on a phone or tablet device. Not only does this mean that library Web sites must keep mobile navigability in mind, but also develop and utilize apps that allow patrons to interact with information and with libraries. While apps do not serve every purpose,…

  14. Two-dimensional BX (X = P, As, Sb) semiconductors with mobilities approaching graphene

    Science.gov (United States)

    Xie, Meiqiu; Zhang, Shengli; Cai, Bo; Zhu, Zhen; Zou, Yousheng; Zeng, Haibo

    2016-07-01

    Carrier mobility plays a key role in the performance of microelectronic devices, especially the field effect transistors (FET). To design next generation two-dimensional (2D) FET, stable channel materials with a higher carrier mobility than silicon and a significant band gap are highly desirable, but are still not discovered. Here, we report a group of 2D materials of BX (X = P, As, and Sb), which are semiconducting with an ultrahigh carrier mobility. Using first-principles calculations, we find that all BX configurations are similar to graphene, but possess direct bandgaps of 1.36, 1.14, and 0.49 eV, respectively. Based on deformation potential theory, BX monolayers are predicted to have superior mobilities (>104 cm2 V-1 s-1) to phosphorene. In particular, the electron mobility of monolayer BSb is 3.2 × 105 cm2 V-1 s-1, approaching the figure of merit in graphene (~3 × 105 cm2 V-1 s-1). These results demonstrate that BX monolayers are of paramount significance for next-generation 2D FET manufacture.Carrier mobility plays a key role in the performance of microelectronic devices, especially the field effect transistors (FET). To design next generation two-dimensional (2D) FET, stable channel materials with a higher carrier mobility than silicon and a significant band gap are highly desirable, but are still not discovered. Here, we report a group of 2D materials of BX (X = P, As, and Sb), which are semiconducting with an ultrahigh carrier mobility. Using first-principles calculations, we find that all BX configurations are similar to graphene, but possess direct bandgaps of 1.36, 1.14, and 0.49 eV, respectively. Based on deformation potential theory, BX monolayers are predicted to have superior mobilities (>104 cm2 V-1 s-1) to phosphorene. In particular, the electron mobility of monolayer BSb is 3.2 × 105 cm2 V-1 s-1, approaching the figure of merit in graphene (~3 × 105 cm2 V-1 s-1). These results demonstrate that BX monolayers are of paramount significance for

  15. SOARAN: A Service-oriented Architecture for Radio Access Network Sharing in Evolving Mobile Networks

    OpenAIRE

    He, Jun; Song, Wei

    2015-01-01

    Mobile networks are undergoing fast evolution to software-defined networking (SDN) infrastructure in order to accommodate the ever-growing mobile traffic and overcome the network management nightmares caused by unremitting acceleration in technology innovations and evolution of the service market.Enabled by virtualized network functionalities, evolving carrier wireless networks tend to share radio access network (RAN) among multiple (virtual) network operators so as to increase network capaci...

  16. Carrier Transport Enhancement in Conjugated Polymers through Interfacial Self-Assembly of Solution-State Aggregates

    KAUST Repository

    Zhao, Kui

    2016-07-13

    We demonstrate that local and long range orders of poly(3-hexylthiophene) (P3HT) semicrystalline films can be synergistically improved by combining chemical functionalization of the dielectric surface with solution-state disentanglement and pre-aggregation of P3HT in a theta solvent, leading to a very significant enhancement of the field effect carrier mobility. The pre-aggregation and surface functionalization effects combine to enhance the carrier mobility nearly 100-fold as compared with standard film preparation by spin-coating, and nearly 10-fold increase over the benefits of pre-aggregation alone. In situ quartz crystal microbalance with dissipation (QCM-D) experiments reveal enhanced deposition of pre-aggregates on surfaces modified with an alkyl-terminated self-assembled monolayer (SAM) in comparison to un-aggregated polymer chains. Additional investigations reveal the combined pre-aggregation and surface functionalization significantly enhances local order of the conjugated polymer through planarization and extension of the conjugated backbone of the polymer which clearly translate to significant improvements of carrier transport at the semiconductor-dielectric interface in organic thin film transistors. This study points to opportunities in combining complementary routes, such as well-known pre-aggregation with substrate chemical functionalization, to enhance the polymer self-assembly and improve its interfacial order with benefits for transport properties.

  17. Concentration dependence of the transport energy level for charge carriers in organic semiconductors

    Science.gov (United States)

    Oelerich, J. O.; Huemmer, D.; Weseloh, M.; Baranovskii, S. D.

    2010-10-01

    The concept of the transport energy (TE) has proven to be one of the most powerful theoretical approaches to describe charge transport in organic semiconductors. In the recent paper L. Li, G. Meller, and H. Kosina [Appl. Phys. Lett. 92, 013307 (2008)] have studied the effect of the partially filled localized states on the position of the TE level. We show that the position of the TE is essentially different to the one suggested by L. Li, G. Meller, and H. Kosina [Appl. Phys. Lett. 92, 013307 (2008)] We further modify the standard TE approach taking into account the percolation nature of the transport path. Our calculations show that the TE becomes dependent on the concentration of charge carriers n at much higher n values than those, at which the carrier mobility already strongly depends on n. Hence the calculations of the concentration-dependent carrier mobility cannot be performed within the approach, in which only the concentration dependence of the TE is taken into account.

  18. Extended carrier lifetimes and diffusion in hybrid perovskites revealed by Hall effect and photoconductivity measurements.

    Science.gov (United States)

    Chen, Y; Yi, H T; Wu, X; Haroldson, R; Gartstein, Y N; Rodionov, Y I; Tikhonov, K S; Zakhidov, A; Zhu, X-Y; Podzorov, V

    2016-01-01

    Impressive performance of hybrid perovskite solar cells reported in recent years still awaits a comprehensive understanding of its microscopic origins. In this work, the intrinsic Hall mobility and photocarrier recombination coefficient are directly measured in these materials in steady-state transport studies. The results show that electron-hole recombination and carrier trapping rates in hybrid perovskites are very low. The bimolecular recombination coefficient (10(-11) to 10(-10) cm(3) s(-1)) is found to be on par with that in the best direct-band inorganic semiconductors, even though the intrinsic Hall mobility in hybrid perovskites is considerably lower (up to 60 cm(2) V(-1) s(-1)). Measured here, steady-state carrier lifetimes (of up to 3 ms) and diffusion lengths (as long as 650 μm) are significantly longer than those in high-purity crystalline inorganic semiconductors. We suggest that these experimental findings are consistent with the polaronic nature of charge carriers, resulting from an interaction of charges with methylammonium dipoles. PMID:27477058

  19. Extended carrier lifetimes and diffusion in hybrid perovskites revealed by Hall effect and photoconductivity measurements

    Science.gov (United States)

    Chen, Y.; Yi, H. T.; Wu, X.; Haroldson, R.; Gartstein, Y. N.; Rodionov, Y. I.; Tikhonov, K. S.; Zakhidov, A.; Zhu, X.-Y.; Podzorov, V.

    2016-08-01

    Impressive performance of hybrid perovskite solar cells reported in recent years still awaits a comprehensive understanding of its microscopic origins. In this work, the intrinsic Hall mobility and photocarrier recombination coefficient are directly measured in these materials in steady-state transport studies. The results show that electron-hole recombination and carrier trapping rates in hybrid perovskites are very low. The bimolecular recombination coefficient (10-11 to 10-10 cm3 s-1) is found to be on par with that in the best direct-band inorganic semiconductors, even though the intrinsic Hall mobility in hybrid perovskites is considerably lower (up to 60 cm2 V-1 s-1). Measured here, steady-state carrier lifetimes (of up to 3 ms) and diffusion lengths (as long as 650 μm) are significantly longer than those in high-purity crystalline inorganic semiconductors. We suggest that these experimental findings are consistent with the polaronic nature of charge carriers, resulting from an interaction of charges with methylammonium dipoles.

  20. Charge carrier concentration dependence of encounter-limited bimolecular recombination in phase-separated organic semiconductor blends

    Science.gov (United States)

    Heiber, Michael C.; Nguyen, Thuc-Quyen; Deibel, Carsten

    2016-05-01

    Understanding how the complex intermolecular configurations and nanostructure present in organic semiconductor donor-acceptor blends impacts charge carrier motion, interactions, and recombination behavior is a critical fundamental issue with a particularly major impact on organic photovoltaic applications. In this study, kinetic Monte Carlo (KMC) simulations are used to numerically quantify the complex bimolecular charge carrier recombination behavior in idealized phase-separated blends. Recent KMC simulations have identified how the encounter-limited bimolecular recombination rate in these blends deviates from the often used Langevin model and have been used to construct the new power mean mobility model. Here, we make a challenging but crucial expansion to this work by determining the charge carrier concentration dependence of the encounter-limited bimolecular recombination coefficient. In doing so, we find that an accurate treatment of the long-range electrostatic interactions between charge carriers is critical, and we further argue that many previous KMC simulation studies have used a Coulomb cutoff radius that is too small, which causes a significant overestimation of the recombination rate. To shed more light on this issue, we determine the minimum cutoff radius required to reach an accuracy of less than ±10 % as a function of the domain size and the charge carrier concentration and then use this knowledge to accurately quantify the charge carrier concentration dependence of the recombination rate. Using these rigorous methods, we finally show that the parameters of the power mean mobility model are determined by a newly identified dimensionless ratio of the domain size to the average charge carrier separation distance.

  1. mSpace Mobile: Exploring Support for Mobile Tasks

    OpenAIRE

    Wilson, Max L.; Russell, Alistair; Smith, Daniel A.; Schraefel, M. C.

    2006-01-01

    In the following paper we present a formative study comparing two Web application interfaces, mSpace Mobile and Google Local in supporting Web-based location discovery tasks on mobile devices while stationary and while on the move. While mSpace Mobile performed well in both stationary and mobile conditions, performance in Google Local dropped significantly in the mobile condition. We postulate that mSpace Mobile performed better because it breaks the paradigm of the page for delivering Web co...

  2. Skylab mobile laboratory

    Science.gov (United States)

    Primeaux, G. R.; Larue, M. A.

    1975-01-01

    The Skylab mobile laboratory was designed to provide the capability to obtain necessary data on the Skylab crewmen 30 days before lift-off, within 1 hour after recovery, and until preflight physiological baselines were reattained. The mobile laboratory complex consisted of six laboratories that supported cardiovascular, metabolic, nutrition and endocrinology, operational medicine, blood, and microbiology experiments; a utility package; and two shipping containers. The objectives and equipment requirements of the Skylab mobile laboratory and the data acquisition systems are discussed along with processes such as permanently mounting equipment in the individual laboratories and methods of testing and transporting the units. The operational performance, in terms of amounts of data collected, and the concept of mobile laboratories for medical and scientific experiments are evaluated. The Skylab mobile laboratory succeeded in facilitating the data collection and sample preservation associated with the three Skylab manned flights.

  3. European mobility cultures

    DEFF Research Database (Denmark)

    Haustein, Sonja; Nielsen, Thomas A. Sick

    2016-01-01

    More targeted European policies promoting green travel patterns require better knowledge on differing mobility cultures across European regions. As a basis for this, we clustered the EU population into eight mobility styles based on Eurobarometer data. The mobility styles - including, for example......, "green cyclists" and "convenience drivers" - differed not only in their travel-related variables but also in their socio-economic background, IT-affinity, and life satisfaction, with green cyclist showing the highest life satisfaction and two car-oriented styles having the highest socio...... positions on the path towards sustainable mobility and therefore different requirements towards European platforms and support measures, e.g. for 'Sustainable Urban Mobility Plans'. The country clusters can provide a starting point for future communication and targeting of European efforts in sustainable...

  4. Talk, Mobility and Materialities

    DEFF Research Database (Denmark)

    McIlvenny, Paul

    The intersection of the quotidian practices of social interaction, learning and mobility outside of the classroom – for example, the ways in which talk shapes how children learn to be actively mobile – has been little studied until recently. This paper develops a social interactional approach to...... analysing talk and mobile action in what are arguably two quintessentially Nordic mobility practices, namely cycling and skiing. More specifically the focus is on investigating and comparing how a child learns to cycle in a bike-friendly urban infrastructure, and how a child learns to ski cross......-country, both within the context of familial social interaction. Audiovisual data was collected with mobile video cameras from family bike rides in Denmark and family skiing in Finland, in which among other things a parent instructs and guides a child to bike or to ski. Using an EMCA approach, the analysis...

  5. Children's velo-mobility

    DEFF Research Database (Denmark)

    Carstensen, Trine Agervig; Nielsen, Thomas Sick; Olafsson, Anton Stahl

    2014-01-01

    Sustainable mobilities play a dominate role in low carbon futures and cycling is an integral element. Children are heirs of transport cultures and crucial for future sustainable mobility. Moreover cycling is important for children’s independent mobility and geographical experience. Dominating...... approaches in transport research, including cycling, understand travel behaviour individualistic and lack to grasp the relational complexities, which are inevitable when considering children’s mobilities. Furthermore has children’s cycling largely been studied as independent mobility and active school travel....... How cycling is learned and constituted, and how cycling skills are consolidated, extended and turned into a stabilized practice remains unstudied. Drawing on in-depth interview data from the region of Copenhagen, Denmark, among families with children (N=20) the paper provides new insights into how...

  6. Promoting regional mobility

    DEFF Research Database (Denmark)

    Jensen, Anne

    . Development of pricing policies is contested at Community level and has taken place in a clash between different policy rationalities. Significantly though, the effects of the pricing policies are closely related to regional mobility systems, e.g. through financing large trans-border infrastructure projects...... and establishing common technical charging systems thus changing the conditions for regional mobility. This paper explores how policies of infrastructure pricing shape new ways of governing mobility which influences trans-border, regional policy-making. The key findings are that there is a tendency to...... include ideas of mobility as a narrative in community transport policy which further that through Community pricing policies, the conditions for mobility is enhanced in a Community perspective. However, when this is connected to infrastructure pricing, the effect is largest at a regional scale. Further...

  7. MOBILIZING KNOWLEDGE IN DENMARK

    DEFF Research Database (Denmark)

    Holm, Claus

    2011-01-01

    Knowledge mobilization is not only a new expression in a Danish context. It is also an interesting concept to introduce and discuss. For doesn’t knowledge mobilization have more – or, at least, as much – to do with politics as with education research or education in itself? Doesn’t modern knowledge...... mobilization have to do with a new political will to mobilize the population by creating a connection between education research and education? On the basis of this report on the Danish efforts with respect to ’knowledge mobilization’, these questions can be answered affirmatively; the extent of knowledge...... mobilization in relation to education research depends on the political will for it. To what extent is it present in Denmark? On one hand, it is whole-heartedly present in Denmark, where national competitive ability is formulated from an ideal of the population’s competitive ability – a sort of popular...

  8. 49 CFR 1139.22 - Revenue data for study carriers.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 8 2010-10-01 2010-10-01 false Revenue data for study carriers. 1139.22 Section... BOARD, DEPARTMENT OF TRANSPORTATION RULES OF PRACTICE PROCEDURES IN MOTOR CARRIER REVENUE PROCEEDINGS Intercity Bus Industry § 1139.22 Revenue data for study carriers. The study carriers, as identified...

  9. 76 FR 32390 - Motor Carrier Safety Advisory Committee Public Meeting

    Science.gov (United States)

    2011-06-06

    ... Federal Motor Carrier Safety Administration Motor Carrier Safety Advisory Committee Public Meeting AGENCY: Federal Motor Carrier Safety Administration (FMCSA), DOT. ACTION: Notice of Motor Carrier Safety Advisory... MCSAC will complete action on Task 11-01, regarding Patterns of Safety Violations by Motor...

  10. 75 FR 2923 - Motor Carrier Safety Advisory Committee Public Meeting

    Science.gov (United States)

    2010-01-19

    ... sessions announced on January 5, 2010 (75 FR 285), and elsewhere in today's Federal Register, and to... Federal Motor Carrier Safety Administration Motor Carrier Safety Advisory Committee Public Meeting AGENCY: Federal Motor Carrier Safety Administration (FMCSA), DOT. ACTION: Notice of Motor Carrier Safety...

  11. The impact of neutral impurity concentration on charge drift mobility in germanium

    CERN Document Server

    Mei, H; Wang, G -J; Yang, G

    2016-01-01

    We report a new result of the neutral impurity scattering of electrons and holes that has impact on the charge drift mobility in high purity germanium crystals at 77 Kelvin. The charge carrier concentration, mobility and resistivity are measured by Hall Effect system at 77 Kelvin. We investigated the contribution to the total charge drift mobility from ionized impurity scattering, lattice scattering, and neutral impurity scattering with the best theoretical models and experimental data. Several samples with measured Hall mobility from the grown crystals are used for this investigation. With the measured Hall mobility and ionized impurity concentration as well as the theoretical models, we calculated the neutral impurity concentration by the Matthiessen's rule. As a result, the distributions of the neutral impurity concentrations with respect to the radius of the crystals are obtained. Consequently, we demonstrate that neutral impurity scattering is a significant contribution to the charge drift mobility, whic...

  12. Extracting hot carriers from photoexcited semiconductor nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Xiaoyang

    2014-12-10

    This research program addresses a fundamental question related to the use of nanomaterials in solar energy -- namely, whether semiconductor nanocrystals (NCs) can help surpass the efficiency limits, the so-called “Shockley-Queisser” limit, in conventional solar cells. In these cells, absorption of photons with energies above the semiconductor bandgap generates “hot” charge carriers that quickly “cool” to the band edges before they can be utilized to do work; this sets the solar cell efficiency at a limit of ~31%. If instead, all of the energy of the hot carriers could be captured, solar-to-electric power conversion efficiencies could be increased, theoretically, to as high as 66%. A potential route to capture this energy is to utilize semiconductor nanocrystals. In these materials, the quasi-continuous conduction and valence bands of the bulk semiconductor become discretized due to confinement of the charge carriers. Consequently, the energy spacing between the electronic levels can be much larger than the highest phonon frequency of the lattice, creating a “phonon bottleneck” wherein hot-carrier relaxation is possible via slower multiphonon emission. For example, hot-electron lifetimes as long as ~1 ns have been observed in NCs grown by molecular beam epitaxy. In colloidal NCs, long lifetimes have been demonstrated through careful design of the nanocrystal interfaces. Due to their ability to slow electronic relaxation, semiconductor NCs can in principle enable extraction of hot carriers before they cool to the band edges, leading to more efficient solar cells.

  13. Carbon: Hydrogen carrier or disappearing skeleton?

    International Nuclear Information System (INIS)

    The use of liquid hydrocarbons as energy carriers implies the use of carbon as a carrier for hydrogen to facilitate hydrogen transport and storage. The current trend for liquid energy carriers used in the transport sector is to maximize the load of hydrogen on the carbon carrier. The recently developed Shell Middle Distillate Hydrogenation process for the manufacture of high quality diesel from aromatic refinery streams fits this picture. In the future, the hydrogen required to raise the product H/C ratio will be increasingly produced via gasification of large amounts of heavy residues. In the light of the strong preference towards using liquid fuels in the transport sector, the Shell Middle Distillate Synthesis process to convert natural gas into diesel of very high quality is discussed. Finally, a few comments on the use of hydrogen without a carbon carrier are made. Long lead times and the likelihood of producing the 'first' hydrogen from fossil fuel are highlighted. 13 figs., 6 tabs., 5 refs

  14. Dedicated Carrier Deployment in Heterogeneous Networks with Inter-site Carrier Aggregation

    DEFF Research Database (Denmark)

    Wang, Hua; Rosa, Claudio; Pedersen, Klaus I.

    picos with dedicated carrier deployment. Collaborative inter-site carrier aggregation (CA) is proposed in scenarios with macro+RRH deployment to make an efficient use of the fragmented spectrum from multiple cells. While in scenarios with macro+pico deployment, UEs can only connect to either the...

  15. Miniature Ion-Mobility Spectrometer

    Science.gov (United States)

    Hartley, Frank T.

    2006-01-01

    The figure depicts a proposed miniature ion-mobility spectrometer that would be fabricated by micromachining. Unlike prior ion-mobility spectrometers, the proposed instrument would not be based on a time-of-flight principle and, consequently, would not have some of the disadvantageous characteristics of prior time-of-flight ion-mobility spectrometers. For example, one of these characteristics is the need for a bulky carrier-gas-feeding subsystem that includes a shutter gate to provide short pulses of gas in order to generate short pulses of ions. For another example, there is need for a complex device to generate pulses of ions from the pulses of gas and the device is capable of ionizing only a fraction of the incoming gas molecules; these characteristics preclude miniaturization. In contrast, the proposed instrument would not require a carrier-gas-feeding subsystem and would include a simple, highly compact device that would ionize all the molecules passing through it. The ionization device in the proposed instrument would be a 0.1-micron-thick dielectric membrane with metal electrodes on both sides. Small conical holes would be micromachined through the membrane and electrodes. An electric potential of the order of a volt applied between the membrane electrodes would give rise to an electric field of the order of several megavolts per meter in the submicron gap between the electrodes. An electric field of this magnitude would be sufficient to ionize all the molecules that enter the holes. Ionization (but not avalanche arcing) would occur because the distance between the ionizing electrodes would be less than the mean free path of gas molecules at the operating pressure of instrument. An accelerating grid would be located inside the instrument, downstream from the ionizing membrane. The electric potential applied to this grid would be negative relative to the potential on the inside electrode of the ionizing membrane and would be of a magnitude sufficient to

  16. Mobile IPTV: Implications for Education

    OpenAIRE

    Pannee Suanpang

    2013-01-01

    Mobile IPTV (Internet Protocol Television) provides digital content which users watch as a television broadcast via the Internet on a mobile device. This paper presents the development of IPTV, Suan Dusit Internet Broadcasting, (SDIB) to mobile IPTV and discusses the implications for education. Mobile IPTV was developed as a prototype and designed to support users via wireless and mobile networks regardless of the mobile device. The system can be broadcasted through both live and video on dem...

  17. HUMAN INTERACTION WITH MOBILE APPLICATIONS

    OpenAIRE

    Alin Zamfiroiu; Emanuel Herteliu; Bogdan Vintila

    2012-01-01

    Computing - human interaction is a very important paradigm because informatics applications are created to be used by people via human interaction. Nowadays mobile applications are more used so is necessarily to talk about mobile - human interaction. In this paper types of mobile devices are presented. Citizen oriented character of mobile application and his utility are described. Different means of interactions with mobile devices are analyzed and in the end of the paper direction of mobile ...

  18. Carrier lifetimes in thin-film photovoltaics

    Science.gov (United States)

    Baek, Dohyun

    2015-09-01

    The carrier lifetimes in thin-film solar cells are reviewed and discussed. Shockley-Read-Hall recombination is dominant at low carrier density, Auger recombination is dominant under a high injection condition and high carrier density, and surface recombination is dominant under any conditions. Because the surface photovoltage technique is insensitive to the surface condition, it is useful for bulk lifetime measurements. The photoconductance decay technique measures the effective recombination lifetime. The time-resolved photoluminescence technique is very useful for measuring thin-film semiconductor or solar-cell materials lifetime, because the sample is thin, other techniques are not suitable for measuring the lifetime. Many papers have provided time-resolved photoluminescence (TRPL) lifetimes for copper-indium-gallium-selenide (CIGS) and CdTe thin-film solar cell. The TRPL lifetime strongly depends on open-circuit voltage and conversion efficiency; however, the TRPL life time is insensitive to the short-circuit current.

  19. Hot Carrier extraction with plasmonic broadband absorbers

    CERN Document Server

    Ng, Charlene; Dligatch, Svetlana; Roberts, Ann; Davis, Timothy J; Mulvaney, Paul; Gomez, Daniel E

    2016-01-01

    Hot charge carrier extraction from metallic nanostructures is a very promising approach for applications in photo-catalysis, photovoltaics and photodetection. One limitation is that many metallic nanostructures support a single plasmon resonance thus restricting the light-to-charge-carrier activity to a spectral band. Here we demonstrate that a monolayer of plasmonic nanoparticles can be assembled on a multi-stack layered configuration to achieve broad-band, near-unit light absorption, which is spatially localised on the nanoparticle layer. We show that this enhanced light absorbance leads to $\\sim$ 40-fold increases in the photon-to-electron conversion efficiency by the plasmonic nanostructures. We developed a model that successfully captures the essential physics of the plasmonic hot-electron charge generation and separation in these structures. This model also allowed us to establish that efficient hot carrier extraction is limited to spectral regions where the photons possessing energies higher than the S...

  20. Client Mobile Software Design Principles for Mobile Learning Systems

    Directory of Open Access Journals (Sweden)

    Qing Tan

    2009-01-01

    Full Text Available In a client-server mobile learning system, client mobile software must run on the mobile phone to acquire, package, and send student’s interaction data via the mobile communications network to the connected mobile application server. The server will receive and process the client data in order to offer appropriate content and learning activities. To develop the mobile learning systems there are a number of very important issues that must be addressed. Mobile phones have scarce computing resources. They consist of heterogeneous devices and use various mobile operating systems, they have limitations with their user/device interaction capabilities, high data communications cost, and must provide for device mobility and portability. In this paper we propose five principles for designing Client mobile learning software. A location-based adaptive mobile learning system is presented as a proof of concept to demonstrate the applicability of these design principles.