A kinetic Monte Carlo model with improved charge injection model for the photocurrent characteristics of organic solar cells

Science.gov (United States)

Kipp, Dylan; Ganesan, Venkat

2013-06-01

We develop a kinetic Monte Carlo model for photocurrent generation in organic solar cells that demonstrates improved agreement with experimental illuminated and dark current-voltage curves. In our model, we introduce a charge injection rate prefactor to correct for the electrode grid-size and electrode charge density biases apparent in the coarse-grained approximation of the electrode as a grid of single occupancy, charge-injecting reservoirs. We use the charge injection rate prefactor to control the portion of dark current attributed to each of four kinds of charge injection. By shifting the dark current between electrode-polymer pairs, we align the injection timescales and expand the applicability of the method to accommodate ohmic energy barriers. We consider the device characteristics of the ITO/PEDOT/PSS:PPDI:PBTT:Al system and demonstrate the manner in which our model captures the device charge densities unique to systems with small injection energy barriers. To elucidate the defining characteristics of our model, we first demonstrate the manner in which charge accumulation and band bending affect the shape and placement of the various current-voltage regimes. We then discuss the influence of various model parameters upon the current-voltage characteristics.

Lattice Issues of the CERN PSB with H- Charge exchange injection hardware

CERN Document Server

Aiba, M; Chanel, M; Goddard, B; Martini, M; Weterings, W

2010-01-01

The motivation for the construction of CERN Linac4 is to improve the performance of the PSB by raising the injection energy and implementing a new H- charge exchange multiturn injection scheme. Lattice perturbations introduced by the new injection hardware are described. Strategies to mitigate the consequences, first by minimizing the additional focusing introduced and, by compensating the residual perturbation, are reported.

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

Energy Technology Data Exchange (ETDEWEB)

Hussain, Afzal

2010-12-16

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

Influence of negative charge on the optical properties of a silver sol

Directory of Open Access Journals (Sweden)

JOVAN M. NEDELJKOVIC

2000-03-01

Full Text Available The effects of negative charge on the optical properties of a silver sol prepared using sodium borohydride as a reductant were studied. The oscillations in the position of the maximum and the intensity of the surface plasmon absorption band were obesrved. The observed effects were explained as a consequence of the fluctuation of the density of free electrons due to the alternate charging and discharging of the silver particles. The charging process involves electron injection from borohydride ions and intermediate species formed during the course of the metal-catalyzed hydrolysis of borohydride ions (BH3OH-, BH2(OH2 and BH(OH3- into the silver particles, while discharge of the silver sol, by reduction of water to hydrogen, limits the attainable negative charge on the particles.

Estimation of instantaneous heat transfer coefficients for a direct-injection stratified-charge rotary engine

Science.gov (United States)

Lee, C. M.; Addy, H. E.; Bond, T. H.; Chun, K. S.; Lu, C. Y.

1987-01-01

The main objective of this report was to derive equations to estimate heat transfer coefficients in both the combustion chamber and coolant pasage of a rotary engine. This was accomplished by making detailed temperature and pressure measurements in a direct-injection stratified-charge rotary engine under a range of conditions. For each sppecific measurement point, the local physical properties of the fluids were calculated. Then an empirical correlation of the coefficients was derived by using a multiple regression program. This correlation expresses the Nusselt number as a function of the Prandtl number and Reynolds number.

Extraction method of interfacial injected charges for SiC power MOSFETs

Science.gov (United States)

Wei, Jiaxing; Liu, Siyang; Li, Sheng; Song, Haiyang; Chen, Xin; Li, Ting; Fang, Jiong; Sun, Weifeng

2018-01-01

An improved novel extraction method which can characterize the injected charges along the gate oxide interface for silicon carbide (SiC) power metal-oxide-semiconductor field-effect transistors (MOSFETs) is proposed. According to the different interface situations of the channel region and the junction FET (JFET) region, the gate capacitance versus gate voltage (Cg-Vg) curve of the device can be divided into three relatively independent parts, through which the locations and the types of the charges injected in to the oxide above the interface can be distinguished. Moreover, the densities of these charges can also be calculated by the amplitudes of the shifts in the Cg-Vg curve. The correctness of this method is proved by TCAD simulations. Moreover, experiments on devices stressed by unclamped-inductive-switching (UIS) stress and negative bias temperature stress (NBTS) are performed to verify the validity of this method.

Influence of space charge during the injection in Saturne II

International Nuclear Information System (INIS)

Lemaire, J.L.

Calculations were made in which a fixed acceptance window, established since the beginning of the injection, was considered, and a filling pattern that was a linear function of time was supposed. Evidently, these conditions are no longer met if the space charge modifies the wave number of the beam and, consequently, the filling rate changes with time. The importance of these conditions upon injection for the theoretical operation point zone 3 is reported

The Role of Dopant Ions on Charge Injection and Transport in Electrochemically Doped Quantum Dot Films.

Science.gov (United States)

Gudjonsdottir, Solrun; van der Stam, Ward; Kirkwood, Nicholas; Evers, Wiel H; Houtepen, Arjan J

2018-05-16

Control over the charge density is very important for implementation of colloidal semiconductor nanocrystals into various optoelectronic applications. A promising approach to dope nanocrystal assemblies is charge injection by electrochemistry, in which the charge compensating electrolyte ions can be regarded as external dopant ions. To gain insight into the doping mechanism and the role of the external dopant ions, we investigate charge injection in ZnO nanocrystal assemblies for a large series of charge compensating electrolyte ions with spectroelectrochemical and electrochemical transistor measurements. We show that charge injection is limited by the diffusion of cations in the nanocrystal films as their diffusion coefficient are found to be ∼7 orders of magnitude lower than those of electrons. We further show that the rate of charge injection depends strongly on the cation size and cation concentration. Strikingly, the onset of electron injection varies up to 0.4 V, depending on the size of the electrolyte cation. For the small ions Li + and Na + the onset is at significantly less negative potentials. For larger ions (K + , quaternary ammonium ions) the onset is always at the same, more negative potential, suggesting that intercalation may take place for Li + and Na + . Finally, we show that the nature of the charge compensating cation does not affect the source-drain electronic conductivity and mobility, indicating that shallow donor levels from intercalating ions fully hybridize with the quantum confined energy levels and that the reorganization energy due to intercalating ions does not strongly affect electron transport in these nanocrystal assemblies.

The Role of Dopant Ions on Charge Injection and Transport in Electrochemically Doped Quantum Dot Films

Science.gov (United States)

2018-01-01

Control over the charge density is very important for implementation of colloidal semiconductor nanocrystals into various optoelectronic applications. A promising approach to dope nanocrystal assemblies is charge injection by electrochemistry, in which the charge compensating electrolyte ions can be regarded as external dopant ions. To gain insight into the doping mechanism and the role of the external dopant ions, we investigate charge injection in ZnO nanocrystal assemblies for a large series of charge compensating electrolyte ions with spectroelectrochemical and electrochemical transistor measurements. We show that charge injection is limited by the diffusion of cations in the nanocrystal films as their diffusion coefficient are found to be ∼7 orders of magnitude lower than those of electrons. We further show that the rate of charge injection depends strongly on the cation size and cation concentration. Strikingly, the onset of electron injection varies up to 0.4 V, depending on the size of the electrolyte cation. For the small ions Li+ and Na+ the onset is at significantly less negative potentials. For larger ions (K+, quaternary ammonium ions) the onset is always at the same, more negative potential, suggesting that intercalation may take place for Li+ and Na+. Finally, we show that the nature of the charge compensating cation does not affect the source-drain electronic conductivity and mobility, indicating that shallow donor levels from intercalating ions fully hybridize with the quantum confined energy levels and that the reorganization energy due to intercalating ions does not strongly affect electron transport in these nanocrystal assemblies. PMID:29718666

Electrical and dielectric properties of foam injection-molded polypropylene/multiwalled carbon nanotube composites

Energy Technology Data Exchange (ETDEWEB)

Ameli, A.; Nofar, M.; Saniei, M.; Hossieny, N.; Park, C. B. [Microcellular Plastics Manufacturing Laboratory, Department of Mechanical and Industrial Engineering, University of Toronto, 5 King’s College Road, Toronto, Ontario, Canada M5S 3G8 (Canada); Pötschke, P. [Leibniz-Institut für Polymerforschung Dresden e.V. (IPF), Hohe Strasse 6, D-01069 Dresden (Germany)

2015-05-22

A combination of high dielectric permittivity (ε′) and low dielectric loss (tan δ) is required for charge storage applications. In percolative systems such as conductive polymer composites, however, obtaining high ε′ and low tan δ is very challenging due to the sharp insulation-conduction transition near the threshold region. Due to the particular arrangement of conductive fillers induced by both foaming and injection molding processes, they may address this issue. Therefore, this work evaluates the application of foam injection molding process in fabricating polymer nanocomposites for energy storage. Polypropylene-multiwalled carbon nanotubes (PP-MWCNT) composites were prepared by melt mixing and foamed in an injection molding process. Electrical conductivity (σ), ε′ and tan δ were then characterized. Also, scanning and transmission electron microscopy (SEM and TEM) was used to investigate the carbon nanotube’s arrangement as well as cellular morphology. The results showed that foam injection-molded composites exhibited highly superior dielectric properties to those of solid counterparts. For instance, foamed samples had ε′=68.3 and tan δ =0.05 (at 1.25 vol.% MWCNT), as opposed to ε′=17.8 and tan δ=0.04 in solid samples (at 2.56 vol.% MWCNT). The results of this work reveal that high performance dielectric nanocomposites can be developed using foam injection molding technologies for charge storage applications.

The influence of charge injection from intermediate connectors on the performance of tandem organic light-emitting devices

Energy Technology Data Exchange (ETDEWEB)

Zhou, Dong-Ying [Institute of Functional Nano and Soft Materials (FUNSOM), Soochow University, Suzhou, Jiangsu 215123 (China); Department of Electrical and Computer Engineering and Waterloo Institute for Nanotechnology, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1 (Canada); Siboni, Hossein Zamani; Wang, Qi; Aziz, Hany, E-mail: lsliao@suda.edu.cn, E-mail: h2aziz@uwaterloo.ca [Department of Electrical and Computer Engineering and Waterloo Institute for Nanotechnology, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1 (Canada); Liao, Liang-Sheng, E-mail: lsliao@suda.edu.cn, E-mail: h2aziz@uwaterloo.ca [Institute of Functional Nano and Soft Materials (FUNSOM), Soochow University, Suzhou, Jiangsu 215123 (China)

2014-12-14

Charge generation in a typical intermediate connector, composed of “n-type doped layer/transition metal oxide (TMO)/hole transporting layer (HTL),” of a tandem organic light-emitting device (OLED) has recently been found to arise from charge transfer at the TMO/HTL interfaces. In this paper, we investigate the effect of hole injection barriers from intermediate connectors on the performance of tandem OLEDs. The hole injection barriers are caused by the offset of the highest occupied molecular orbital (HOMO) energy levels between HTLs contained in the intermediate connector and the top electroluminescence (EL) unit. We also find that although charge generation can occur at the interfaces between the TMO and a wide variety of HTLs of different HOMO values, an increase in the hole injection barrier however limits the electroluminescence efficiency of the top EL units. In the case of large hole injection barriers, significant charge accumulation in the HTLs makes the intermediate connector lose its functionality gradually over operating time, and limits device stability.

Construction of a Direct Water-Injected Two-Stroke Engine for Phased Direct Fuel Injection-High Pressure Charging Investigations

Science.gov (United States)

Somsel, James P.

1998-01-01

The development of a water injected Orbital Combustion Process (OCP) engine was conducted to assess the viability of using the powerplant for high altitude NASA aircraft and General Aviation (GA) applications. An OCP direct fuel injected, 1.2 liter, three cylinder, two-stroke engine has been enhanced to independently inject water directly into the combustion chamber. The engine currently demonstrates low brake specific fuel consumption capability and an excellent power to weight ratio. With direct water injection, significant improvements can be made to engine power, to knock limits/ignition advance timing, and to engine NO(x) emissions. The principal aim of the testing was to validate a cyclic model developed by the Systems Analysis Branch at NASA Ames Research Center. The work is a continuation of Ames' investigations into a Phased Direct Fuel Injection Engine with High Pressure Charging (PDFI-ITPC).

Impact of physical properties of biodiesel on the injection process in a common-rail direct injection system

International Nuclear Information System (INIS)

Boudy, Frederic; Seers, Patrice

2009-01-01

This paper presents the influence of biodiesel fuel properties on the injection mass flow rate of a diesel common-rail injection system. Simulations are first performed with ISO 4113 diesel fuel on a four-cylinder common-rail system to evaluate a single and triple injection strategies. For each injection strategy, the impact of modifying a single fuel property at a time is evaluated so as to quantify its influence on the injection process. The results show that fuel density is the main property that affects the injection process, such as total mass injected and pressure wave in the common-rail system. The fuel's viscosity and bulk modulus also influence, but to a lessen degree, the mass flow rate of the injector notably during multiple injection strategies as individual properties change the fuel's dampening property and friction coefficient.

Influence of injected charge carriers on photocurrents in polymer solar cells

NARCIS (Netherlands)

Wehenkel, D.J.; Koster, L.J.A.; Wienk, M.M.; Janssen, R.A.J.

2012-01-01

We determine and analyze the photocurrent Jph in polymer solar cells under conditions where, no, one, or two different charge carriers can be injected by choosing appropriate electrodes and compare the experimental results to simulations based on a drift-diffusion device model that accounts for

Effect of main injection timing for controlling the combustion phasing of a homogeneous charge compression ignition engine using a new dual injection strategy

International Nuclear Information System (INIS)

Das, Pranab; Subbarao, P.M.V.; Subrahmanyam, J.P.

2015-01-01

Highlights: • A new dual injection concept is developed by minimum geometry modification. • The occurrence of combustion parameters strongly depend on main injection timing. • At higher load, premixed equivalence ratio dominates over main injection timing. • Retarded of main injection timing tends to retard combustion phasing. • Slightly retarded main injection timing is recommended to avoid intense knocking. - Abstract: Homogeneous charge compression ignition combustion of diesel fuel is implemented using a novel dual injection strategy. A new experimental technique is developed to modify a single cylinder direct injection diesel engine to run on homogeneous combustion mode. Effect of main injection timing is investigated covering a range from 26 to 8 crank angle degrees before top dead center with an interval of 3°. Retarded main injection timing is identified as a control strategy for delaying combustion phasing and a means of controlled combustion phasing of direct injection homogeneous charge compression ignition combustion. Two load conditions were investigated and it was observed that at higher load, start of combustion depends more on fuel air equivalence ratio than main injection timing, whereas at low load, it significantly varies with varying main injection timing. Significant improvements in smoke and oxides of nitrogen emissions are observed when compared with the baseline conventional combustion. By studying different combustion parameters, it is observed that there is an improvement in performance and emissions with marginal loss in thermal efficiency when the main injection timing is 20° before top dead center. This is identified as the optimum main injection timing for such homogeneous combustion under the same operating condition

The Schottky energy barrier dependence of charge injection in organic light-emitting diodes

Science.gov (United States)

Campbell, I. H.; Davids, P. S.; Smith, D. L.; Barashkov, N. N.; Ferraris, J. P.

1998-04-01

We present device model calculations of the current-voltage (I-V) characteristics of organic diodes and compare them with measurements of structures fabricated using MEH-PPV. The structures are designed so that all of the current is injected from one contact. The I-V characteristics are considered as a function of the Schottky energy barrier to charge injection from the contact. Experimentally, the Schottky barrier is varied from essentially zero to more than 1 eV by using different metal contacts. A consistent description of the device I-V characteristics is obtained as the Schottky barrier is varied from small values, less than about 0.4 eV, where the current flow is space-charge limited to larger values where it is contact limited.

The impact of the Fermi-Dirac distribution on charge injection at metal/organic interfaces.

Science.gov (United States)

Wang, Z B; Helander, M G; Greiner, M T; Lu, Z H

2010-05-07

The Fermi level has historically been assumed to be the only energy-level from which carriers are injected at metal/semiconductor interfaces. In traditional semiconductor device physics, this approximation is reasonable as the thermal distribution of delocalized states in the semiconductor tends to dominate device characteristics. However, in the case of organic semiconductors the weak intermolecular interactions results in highly localized electronic states, such that the thermal distribution of carriers in the metal may also influence device characteristics. In this work we demonstrate that the Fermi-Dirac distribution of carriers in the metal has a much more significant impact on charge injection at metal/organic interfaces than has previously been assumed. An injection model which includes the effect of the Fermi-Dirac electron distribution was proposed. This model has been tested against experimental data and was found to provide a better physical description of charge injection. This finding indicates that the thermal distribution of electronic states in the metal should, in general, be considered in the study of metal/organic interfaces.

Theoretical investigation of the charge-transfer properties in different meso-linked zinc porphyrins for highly efficient dye-sensitized solar cells.

Science.gov (United States)

Namuangruk, Supawadee; Sirithip, Kanokkorn; Rattanatwan, Rattanawelee; Keawin, Tinnagon; Kungwan, Nawee; Sudyodsuk, Taweesak; Promarak, Vinich; Surakhot, Yaowarat; Jungsuttiwong, Siriporn

2014-06-28

The charge transfer effect of different meso-substituted linkages on porphyrin analogue 1 (A1, B1 and C1) was theoretically investigated using density functional theory (DFT) and time-dependent DFT (TDDFT) calculations. The calculated geometry parameters and natural bond orbital analysis reveal that the twisted conformation between porphyrin macrocycle and meso-substituted linkages leads to blocking of the conjugation of the conjugated backbone, and the frontier molecular orbital plot shows that the intramolecular charge transfer of A1, B1 and C1 hardly takes place. In an attempt to improve the photoinduced intramolecular charge transfer ability of the meso-linked zinc porphyrin sensitizer, a strong electron-withdrawing group (CN) was introduced into the anchoring group of analogue 1 forming analogue 2 (A2, B2 and C2). The density difference plot of A2, B2 and C2 shows that the charge transfer properties dramatically improved. The electron injection process has been performed using TDDFT; the direct charge-transfer transition in the A2-(TiO2)38 interacting system takes place; our results strongly indicated that introducing electron-withdrawing groups into the acceptor part of porphyrin dyes can fine-tune the effective conjugation length of the π-spacer and improve intramolecular charge transfer properties, consequently inducing the electron injection process from the anchoring group of the porphyrin dye to the (TiO2)38 surface which may improve the conversion efficiency of the DSSCs. Our calculated results can provide valuable information and a promising outlook for computation-aided sensitizer design with anticipated good properties in further experimental synthesis.

Astronomical imaging with a low temperature InSb charge injection device (CID)

International Nuclear Information System (INIS)

Rouan, D.; Lacombe, F.; Tiphene, D.; Stefanovitch, D.; Phan van, D.

1986-01-01

InSb charge injection device (CID) technology focal plane arrays employ two coupled MIS capacitors which collect and store photon-generated charge carriers. Attention is presently given to two-dimensional arrays for 77 K and 4 K operating temperatures in astronomical applications; two such prototypes for ground observations have been developed for use with a 2-m telescope. A CID InSb array is noted to be a useful candidate for the proposed IR Space Observatory's focal plane camera. 7 references

Chemical linkage to injected tissues is a distinctive property of oxidized avidin.

Directory of Open Access Journals (Sweden)

Rita De Santis

Full Text Available We recently reported that the oxidized avidin, named AvidinOX®, resides for weeks within injected tissues as a consequence of the formation of Schiff's bases between its aldehyde groups and tissue protein amino groups. We also showed, in a mouse pre-clinical model, the usefulness of AvidinOX for the delivery of radiolabeled biotin to inoperable tumors. Taking into account that AvidinOX is the first oxidized glycoprotein known to chemically link to injected tissues, we tested in the mouse a panel of additional oxidized glycoproteins, with the aim of investigating the phenomenon. We produced oxidized ovalbumin and mannosylated streptavidin which share with avidin glycosylation pattern and tetrameric structure, respectively and found that neither of them linked significantly to cells in vitro nor to injected tissues in vivo, despite the presence of functional aldehyde groups. The study, extended to additional oxidized glycoproteins, showed that the in vivo chemical conjugation is a distinctive property of the oxidized avidin. Relevance of the high cationic charge of avidin into the stable linkage of AvidinOX to tissues is demonstrated as the oxidized acetylated avidin lost the property. Plasmon resonance on matrix proteins and cellular impedance analyses showed in vitro that avidin exhibits a peculiar interaction with proteins and cells that allows the formation of highly stable Schiff's bases, after oxidation.

Charge injection and accumulation in organic light-emitting diode with PEDOT:PSS anode

Energy Technology Data Exchange (ETDEWEB)

Weis, Martin, E-mail: martin.weis@stuba.sk [Institute of Electronics and Photonics, Slovak University of Technology, Ilkovičova 3, Bratislava 81219 (Slovakia); Otsuka, Takako; Taguchi, Dai; Manaka, Takaaki; Iwamoto, Mitsumasa, E-mail: iwamoto@ome.pe.titech.ac.jp [Department of Physical Electronics, Tokyo Institute of Technology, 2-12-1 O-okayama, Meguro-ku, Tokyo 152-8552 (Japan)

2015-04-21

Organic light-emitting diode (OLED) displays using flexible substrates have many attractive features. Since transparent conductive oxides do not fit the requirements of flexible devices, conductive polymer poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS) has been proposed as an alternative. The charge injection and accumulation in OLED devices with PEDOT:PSS anodes are investigated and compared with indium tin oxide anode devices. Higher current density and electroluminescence light intensity are achieved for the OLED device with a PEDOT:PSS anode. The electric field induced second-harmonic generation technique is used for direct observation of temporal evolution of electric fields. It is clearly demonstrated that the improvement in the device performance of the OLED device with a PEDOT:PSS anode is associated with the smooth charge injection and accumulation.

The Schottky energy barrier dependence of charge injection in organic light-emitting diodes

Energy Technology Data Exchange (ETDEWEB)

Campbell, I.H.; Davids, P.S.; Smith, D.L. [Los Alamos National Laboratory, Los Alamos, New Mexico87545 (United States); Barashkov, N.N.; Ferraris, J.P. [The University of Texas at Dallas, Richardson, Texas75083 (United States)

1998-04-01

We present device model calculations of the current{endash}voltage (I{endash}V) characteristics of organic diodes and compare them with measurements of structures fabricated using MEH-PPV. The structures are designed so that all of the current is injected from one contact. The I{endash}V characteristics are considered as a function of the Schottky energy barrier to charge injection from the contact. Experimentally, the Schottky barrier is varied from essentially zero to more than 1 eV by using different metal contacts. A consistent description of the device I{endash}V characteristics is obtained as the Schottky barrier is varied from small values, less than about 0.4 eV, where the current flow is space-charge limited to larger values where it is contact limited. {copyright} {ital 1998 American Institute of Physics.}

Temperature-dependent charge injection and transport in pentacene thin-film transistors

International Nuclear Information System (INIS)

Kim, Dong Wook; Shin, Hyunji; Choi, Jong Sun; Park, Ji-Ho; Park, Jaehoon

2015-01-01

The electrical characteristics of p-channel pentacene thin-film transistors (TFTs) were analyzed at different operating temperatures ranging from 253 to 353 K. An improvement in the drain current and field-effect mobility of the pentacene TFTs is observed with increasing temperature. From the Arrhenius plots of field-effect mobility extracted at various temperatures, a lower activation energy of 99.34 meV was obtained when the device is operating in the saturation region. Such observation is ascribed to the thermally activated hole transport through the pentacene grain boundaries. On the other hand, it was found that the Au/pentacene contact significantly affects the TFTs electrical characteristics in the linear region, which resulted in a higher activation energy. The activation energy based on the linear field-effect mobility, which increased from 344.61 to 444.70 meV with decreasing temperature, implies the charge-injection-limited electrical behavior of pentacene TFTs at low temperatures. The thermally induced electrical characteristic variations in pentacene TFTs can thus be studied through the temperature dependence of the charge injection and transport processes. (paper)

Charging properties of a dust grain in collisional plasmas

International Nuclear Information System (INIS)

Khrapak, S.A.; Morfill, G.E.; Khrapak, A.G.; D'yachkov, L.G.

2006-01-01

Charging related properties of a small spherical grain immersed in a collisional plasma are investigated. Asymptotic expressions for charging fluxes, grain surface potential, long range electrostatic potential, and the properties of grain charge fluctuations due to the discrete nature of the charging process are obtained. These analytical results are in reasonable agreement with the available results of numerical modeling

Fusion plasma losses due to the charge exchange of injected neutrals

International Nuclear Information System (INIS)

Bender, D.J.; Carlson, G.A.

1975-01-01

The interaction of a neutral beam, consisting of full, half and third energy components, with a mirror plasma is analyzed. The beam-plasma interaction is assumed to occur via ionization and charge exchange collisions. The plasma was approximated as being spherical in shape, having a uniform density, isotropic velocity distribution, and a mirror plasma energy distribution. It was found that to a first approximation, for plasma energies less than 100 keV, the charge exchange power loss (per injected atom) of the half energy component is at least twice that of the full energy component. For the third energy component, the loss is at least three times that of the full energy component. For some plasma conditions, the neutral beam can act as an energy sink for the plasma due to these charge exchange losses. (U.S.)

Effect of Coercive Voltage and Charge Injection on Performance of a Ferroelectric-Gate Thin-Film Transistor

Directory of Open Access Journals (Sweden)

P. T. Tue

2013-01-01

Full Text Available We adopted a lanthanum oxide capping layer between semiconducting channel and insulator layers for fabrication of a ferroelectric-gate thin-film transistor memory (FGT which uses solution-processed indium-tin-oxide (ITO and lead-zirconium-titanate (PZT film as a channel layer and a gate insulator, respectively. Good transistor characteristics such as a high “on/off” current ratio, high channel mobility, and a large memory window of 108, 15.0 cm2 V−1 s−1, and 3.5 V were obtained, respectively. Further, a correlation between effective coercive voltage, charge injection effect, and FGT’s memory window was investigated. It is found that the charge injection from the channel to the insulator layer, which occurs at a high electric field, dramatically influences the memory window. The memory window’s enhancement can be explained by a dual effect of the capping layer: (1 a reduction of the charge injection and (2 an increase of effective coercive voltage dropped on the insulator.

Charge injection engineering of ambipolar field-effect transistors for high-performance organic complementary circuits.

Science.gov (United States)

Baeg, Kang-Jun; Kim, Juhwan; Khim, Dongyoon; Caironi, Mario; Kim, Dong-Yu; You, In-Kyu; Quinn, Jordan R; Facchetti, Antonio; Noh, Yong-Young

2011-08-01

Ambipolar π-conjugated polymers may provide inexpensive large-area manufacturing of complementary integrated circuits (CICs) without requiring micro-patterning of the individual p- and n-channel semiconductors. However, current-generation ambipolar semiconductor-based CICs suffer from higher static power consumption, low operation frequencies, and degraded noise margins compared to complementary logics based on unipolar p- and n-channel organic field-effect transistors (OFETs). Here, we demonstrate a simple methodology to control charge injection and transport in ambipolar OFETs via engineering of the electrical contacts. Solution-processed caesium (Cs) salts, as electron-injection and hole-blocking layers at the interface between semiconductors and charge injection electrodes, significantly decrease the gold (Au) work function (∼4.1 eV) compared to that of a pristine Au electrode (∼4.7 eV). By controlling the electrode surface chemistry, excellent p-channel (hole mobility ∼0.1-0.6 cm(2)/(Vs)) and n-channel (electron mobility ∼0.1-0.3 cm(2)/(Vs)) OFET characteristics with the same semiconductor are demonstrated. Most importantly, in these OFETs the counterpart charge carrier currents are highly suppressed for depletion mode operation (I(off) 0.1-0.2 mA). Thus, high-performance, truly complementary inverters (high gain >50 and high noise margin >75% of ideal value) and ring oscillators (oscillation frequency ∼12 kHz) based on a solution-processed ambipolar polymer are demonstrated.

Charging dynamics and strong localization of a two-dimensional electron cloud

International Nuclear Information System (INIS)

Dianoux, R; Smilde, H J H; Marchi, F; Buffet, N; Mur, P; Comin, F; Chevrier, J

2007-01-01

The dynamics of charge injection in silicon nanocrystals embedded in a silicon dioxide matrix is studied using electrostatic force microscopy. We show that the presence of silicon nanocrystals with a density of 10 11 cm -2 is essential for strong localization of charges, and results in exceptional charge retention properties compared to nanocrystal-free SiO 2 samples. In both systems, a logarithmic dependence of the diameter of the charged area on the injection time is experimentally observed on a timescale between 0.1 and 10 s (voltage≤10 V). A field-emission injection, limited by Coulomb blockade and a lateral charge spreading due to a repulsive radial electric field are used to model the sample charging. Once the tip is retracted, the electron cloud is strongly confined in the nanocrystals and remains static

Charge transfer and injection barrier at the metal-organic interfaces

Science.gov (United States)

Yan, Li

2002-09-01

The metal-organic interface plays a critical role in determining the functionality and performance of many innovative organic based devices. It has attracted extensive research interests in recent years. This thesis presents investigations of the electronic structures of organic materials, such as tris-(8-hydroxyquinoline) aluminum (Alq3) and copper phthalocyanine (CuPc), during their interface formation with metals. The characterization is accomplished by X-ray and ultraviolet photoelectron spectroscopes (XPS and UPS) and inverse photoelectron spectroscopy (IPES). As discussed herein, both occupied and unoccupied electronic states at the interfaces are carefully examined in different aspects. In Chapter 4, the charge transfer and chemical reaction at various metal/Alq3 interfaces are investigated using XPS and UPS to study the electron injection into the Alga film. Electron transfer from the low work function metal and Al/LiF(CsF) bilayer to the Alga has been observed. The role of the dielectric and possible chemistry at the interface are discussed in comparison of the low work function metals. Further in Chapter 5, the origin of the metal-interface dipole and the estimation of charge injection barrier is explored using several organic materials. A thermodynamic equilibrium model is extended to explain the relation between the charge transfer process ad the interface dipole. Further, in Chapter 6 the combination of XPS, UPS and IPES detailed the evolution of both occupied and unoccupied energy states during the alkali metal doping. The energy gap modification in organic due to metal doping is observed directly for the spectra. Chapter 7 provides stability study of the organic thin films under x-ray and UV light. The results verify the usability of UPS and XPS for the organic materials used in the thesis. Chapter 7 also shows the secondary ion mass spectroscopy results of metal diffusion in organic thin films.

Experimental optimization of a direct injection homogeneous charge compression ignition gasoline engine using split injections with fully automated microgenetic algorithms

Energy Technology Data Exchange (ETDEWEB)

Canakci, M. [Kocaeli Univ., Izmit (Turkey); Reitz, R.D. [Wisconsin Univ., Dept. of Mechanical Engineering, Madison, WI (United States)

2003-03-01

Homogeneous charge compression ignition (HCCI) is receiving attention as a new low-emission engine concept. Little is known about the optimal operating conditions for this engine operation mode. Combustion under homogeneous, low equivalence ratio conditions results in modest temperature combustion products, containing very low concentrations of NO{sub x} and particulate matter (PM) as well as providing high thermal efficiency. However, this combustion mode can produce higher HC and CO emissions than those of conventional engines. An electronically controlled Caterpillar single-cylinder oil test engine (SCOTE), originally designed for heavy-duty diesel applications, was converted to an HCCI direct injection (DI) gasoline engine. The engine features an electronically controlled low-pressure direct injection gasoline (DI-G) injector with a 60 deg spray angle that is capable of multiple injections. The use of double injection was explored for emission control and the engine was optimized using fully automated experiments and a microgenetic algorithm optimization code. The variables changed during the optimization include the intake air temperature, start of injection timing and the split injection parameters (per cent mass of fuel in each injection, dwell between the pulses). The engine performance and emissions were determined at 700 r/min with a constant fuel flowrate at 10 MPa fuel injection pressure. The results show that significant emissions reductions are possible with the use of optimal injection strategies. (Author)

Silver nanoparticles as a key feature of a plasma polymer composite layer in mitigation of charge injection into polyethylene under dc stress

International Nuclear Information System (INIS)

Milliere, L; Makasheva, K; Laurent, C; Despax, B; Boudou, L; Teyssedre, G

2016-01-01

The aim of this work is to limit charge injection from a semi-conducting electrode into low density polyethylene (LDPE) under dc field by tailoring the polymer surface using a silver nanoparticles-containing layer. The layer is composed of a plane of silver nanoparticles embedded in a semi-insulating organosilicon matrix deposited on the polyethylene surface by a plasma process. Size, density and surface coverage of the nanoparticles are controlled through the plasma process. Space charge distribution in 300 μm thick LDPE samples is measured by the pulsed-electroacoustic technique following a short term (step-wise voltage increase up to 50 kV mm −1 , 20 min in duration each, followed by a polarity inversion) and a longer term (up to 12 h under 40 kV mm −1 ) protocols for voltage application. A comparative study of space charge distribution between a reference polyethylene sample and the tailored samples is presented. It is shown that the barrier effect depends on the size distribution and the surface area covered by the nanoparticles: 15 nm (average size) silver nanoparticles with a high surface density but still not percolating form an efficient barrier layer that suppress charge injection. It is worthy to note that charge injection is detected for samples tailored with (i) percolating nanoparticles embedded in organosilicon layer; (ii) with organosilicon layer only, without nanoparticles and (iii) with smaller size silver particles (<10 nm) embedded in organosilicon layer. The amount of injected charges in the tailored samples increases gradually in the samples ranking given above. The mechanism of charge injection mitigation is discussed on the basis of complementary experiments carried out on the nanocomposite layer such as surface potential measurements. The ability of silver clusters to stabilize electrical charges close to the electrode thereby counterbalancing the applied field appears to be a key factor in explaining the charge injection

Study of the charge transport characteristics of dendrimer molecular thin films

Energy Technology Data Exchange (ETDEWEB)

Li, J.C., E-mail: jcli@mail.neu.edu.cn; Han, N.; Wang, S.S.; Ba, D.C.

2011-05-31

In this work, we systematically studied the electrical characteristics of two types of dendritic arylamine thin film devices. We observed that, for devices with different interfacial structures, their charge injection barriers and transport properties are obviously different. The smallest charge injection barrier is observed in dendrimer devices without charge-transfer interfacial layers. The Richardson-Schottky thermionic emission model can be well used to fit the experimental current-voltage characteristics at a lower voltage region. The charge injection barrier increases about 0.4 eV and 0.5 eV when a 1-decanethiol self-assembly layer and -CN terminated dendrimer thin films are inserted as the interfacial layer, respectively. It is shown that the molecule/electrode charge-transfer interfaces can largely affect the device charge injection/transport process and consequently change the device performance. In this case, the space charge limited conduction theory is more applicable to simulate the device conduction mechanism. Owing to its ultra-thin thickness, the self-assembly monolayer technique is proved to be an efficient approach in engineering the interfacial electronic structures of dendrimer thin film devices.

Study of the charge transport characteristics of dendrimer molecular thin films

International Nuclear Information System (INIS)

Li, J.C.; Han, N.; Wang, S.S.; Ba, D.C.

2011-01-01

In this work, we systematically studied the electrical characteristics of two types of dendritic arylamine thin film devices. We observed that, for devices with different interfacial structures, their charge injection barriers and transport properties are obviously different. The smallest charge injection barrier is observed in dendrimer devices without charge-transfer interfacial layers. The Richardson-Schottky thermionic emission model can be well used to fit the experimental current-voltage characteristics at a lower voltage region. The charge injection barrier increases about 0.4 eV and 0.5 eV when a 1-decanethiol self-assembly layer and -CN terminated dendrimer thin films are inserted as the interfacial layer, respectively. It is shown that the molecule/electrode charge-transfer interfaces can largely affect the device charge injection/transport process and consequently change the device performance. In this case, the space charge limited conduction theory is more applicable to simulate the device conduction mechanism. Owing to its ultra-thin thickness, the self-assembly monolayer technique is proved to be an efficient approach in engineering the interfacial electronic structures of dendrimer thin film devices.

i-CELIV technique for investigation of charge carriers transport properties

Energy Technology Data Exchange (ETDEWEB)

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

2016-10-20

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

In vivo charge injection limits increased after 'unsafe' stimulation

DEFF Research Database (Denmark)

Meijs, Suzan; Sørensen, Søren; Rechendorff, Kristian

2015-01-01

was not observed with any of the stimulation protocols and no tissue damage was observed for the 20 mA – 200 Hz stimulation group. This indicates that the ‘safe potential window’ may not be applicable in vivo, as no damage was done stimulating with 20 mA at 200 Hz, while damage was done using the same current......The effect of unsafe stimulation on charge injection limits (Qinj) and pulsing capacitance (Cpulse) was investigated. Four stimulation protocols were applied: 20 mA – 200 and 400 Hz, 50 mA – 200 and 400 Hz. Increasing Qinj and Cpulse were observed for all stimulation protocols. Corrosion...

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

Directory of Open Access Journals (Sweden)

Ahmad Irfan

2016-05-01

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

Optimization of operating conditions in the early direct injection premixed charge compression ignition regime

NARCIS (Netherlands)

Boot, M.D.; Luijten, C.C.M.; Rijk, E.P.; Albrecht, B.A.; Baert, R.S.G.

2009-01-01

Early Direct Injection Premixed Charge Compression Ignition (EDI PCCI) is a widely researched combustion concept, which promises soot and CO2 emission levels of a spark-ignition (SI) and compression-ignition (CI) engine, respectively. Application of this concept to a conventional CI engine using a

Treatment of H0 and H- beams spilled at the stripper foil at full energy charge-exchange injection scheme

International Nuclear Information System (INIS)

Yamane, Isao

1991-01-01

The charge-exchange injection into a synchrotron to generate high-intensity pulsed proton beams for a spallation neutron source is reviewed while focusing on the treatment of H 0 and H - beams spilled at the stripper foil. After charge-exchange injection is briefly outlined, scattering by foil atoms and causes to spill H 0 and H - beams are described. These spilled beams can amount to several μA and should be carefully treated. It is then shown that a direct H - injection system needs to be considerably long and requires a very long straight section. Because of its simplicity, two-step H 0 injection has very wide applicability to various types of rings. However, it has a problem of emittance growth due to angular divergence in the stripper magnet and an ionoptical mismatch at the stripper foil. These problems are discussed, including a new proposal for a measure to remedy this problem. The laser photoionization injection is also briefly mentioned. (author)

On the nature of high field charge transport in reinforced silicone dielectrics: Experiment and simulation

Energy Technology Data Exchange (ETDEWEB)

Huang, Yanhui, E-mail: huangy12@rpi.edu; Schadler, Linda S. [Department of Material Science and Engineering, Rensselaer Polytechnic Institute, 110 8th street, Troy, New York 12180 (United States)

2016-08-07

The high field charge injection and transport properties in reinforced silicone dielectrics were investigated by measuring the time-dependent space charge distribution and the current under dc conditions up to the breakdown field and were compared with the properties of other dielectric polymers. It is argued that the energy and spatial distribution of localized electronic states are crucial in determining these properties for polymer dielectrics. Tunneling to localized states likely dominates the charge injection process. A transient transport regime arises due to the relaxation of charge carriers into deep traps at the energy band tails and is successfully verified by a Monte Carlo simulation using the multiple-hopping model. The charge carrier mobility is found to be highly heterogeneous due to the non-uniform trapping. The slow moving electron packet exhibits a negative field dependent drift velocity possibly due to the spatial disorder of traps.

Thermodynamical and dynamical properties of charged BTZ black holes

Energy Technology Data Exchange (ETDEWEB)

Tang, Zi-Yu; Wang, Bin [Shanghai Jiao Tong University, Department of Physics and Astronomy, Center for Astronomy and Astrophysics, Shanghai (China); Zhang, Cheng-Yong [Peking University, Center for High-Energy Physics, Beijing (China); Kord Zangeneh, Mahdi [Shanghai Jiao Tong University, Department of Physics and Astronomy, Center for Astronomy and Astrophysics, Shanghai (China); Shahid Chamran University of Ahvaz, Physics Department, Faculty of Science, Ahvaz (Iran, Islamic Republic of); Research Institute for Astronomy and Astrophysics of Maragha (RIAAM)-Maragha, P. O. Box: 55134-441, Maragha (Iran, Islamic Republic of); Shiraz University, Physics Department and Biruni Observatory, College of Sciences, Shiraz (Iran, Islamic Republic of); Saavedra, Joel [Pontificia Universidad Catolica de Valparaiso, Instituto de Fisica, Valparaiso (Chile)

2017-06-15

We investigate the spacetime properties of BTZ black holes in the presence of the Maxwell field and Born-Infeld field and find rich properties in the spacetime structures when the model parameters are varied. Employing Landau-Lifshitz theory, we examine the thermodynamical phase transition in the charged BTZ black holes. We further study the dynamical perturbation in the background of the charged BTZ black holes and find different properties in the dynamics when the thermodynamical phase transition occurs. (orig.)

An Injectable Composite Gelatin Hydrogel with pH Response Properties

Directory of Open Access Journals (Sweden)

Baoguo Chen

2017-01-01

Full Text Available On account of minimally invasive procedure and of filling irregular defects of tissues, injectable hydrogels are increasingly attractive in biomedical fields. However, traditional hydrogel formed by simple physical interaction or in situ crosslinking had inevitably some drawbacks such as low mechanical strength and lack of multifunctional properties. Though many investigations had successfully modified traditional injectable hydrogel to obtain both mechanical and functional properties, an acetalated β-cyclodextrin (Ac-β-CD nanoparticle composite injectable hydrogel designed in the research was another effective and efficient choice to solve the drawbacks. First of all, gelatin derivative (G-AA and Ac-β-CD were synthesized to prepare hydrogel and nanoparticle, respectively. In order to ensure good compatibility between nanoparticle and macromonomer and provide crosslink points between nanoparticle and macromonomer, G-AA was simultaneously functionalized onto the surface of Ac-β-CD nanoparticle during the fabrication of Ac-β-CD nanoparticle using one-step method. Finally, injectable composite hydrogel was obtained by photoinitiated polymerization in situ. Hydrogel properties like gelation time and swelling ratio were investigated. The viscoelastic behavior of hydrogels confirmed that typical characteristics of crosslinked elastomer for all hydrogel and nanoparticle in hydrogel could improve the mechanical property of hydrogel. Moreover, the transparency with time had verified obvious acid-response properties of hydrogels.

Performance and combustion characteristics of direct-injection stratified-charge rotary engines

Science.gov (United States)

Nguyen, Hung Lee

1987-01-01

Computer simulations of the direct-injection stratified-charge (DISC) Wankel engine have been used to calculate heat release rates and performance and efficiency characteristics of the 1007R engine. Engine pressure data have been used in a heat release analysis to study the effects of heat transfer, leakage, and crevice flows. Predicted engine performance data are compared with experimental test data over a range of engine speeds and loads. An examination of methods to improve the performance of the Wankel engine with faster combustion, reduced leakage, higher compression ratio, and turbocharging is presented.

Manipulation of charge carrier injection into organic field-effect transistors by self-assembled monolayers of alkanethiols

NARCIS (Netherlands)

Asadi, Kamal; Gholamrezaie, Fatemeh; Smits, Edsger C. P.; Blom, Paul W. M.; de Boer, Bert

2007-01-01

Charge carrier injection into two semiconducting polymers is investigated in field-effect transistors using gold source and drain electrodes that are modified by self-assembled monolayers of alkanethiols and perfluorinated alkanethiols. The presence of an interfacial dipole associated with the

Effect of injection energy on residual dose around the charge exchange foil

Directory of Open Access Journals (Sweden)

Kazami Yamamoto

2012-12-01

Full Text Available The rapid cycling synchrotron (RCS of Japan Proton Accelerator Research Complex (J-PARC and the accumulator ring (AR of Spallation Neutron Source (SNS can be used as high-power pulsed neutron sources. In both cases, the injection region becomes one of the highest activation areas in the ring. However, residual dose distributions have revealed that the highest activation points in the J-PARC RCS and the SNS AR are different in detail. The dose of the charge exchange chamber in the SNS is more than 100 times larger than that of the RCS though the ratio of beam power is less than 10. We investigated the reason of this difference by Geant4 and MARS, and the calculation results indicated that the difference was due to the dependence of the neutron and pion production rate on the injection energy.

Regressed relations for forced convection heat transfer in a direct injection stratified charge rotary engine

Science.gov (United States)

Lee, Chi M.; Schock, Harold J.

1988-01-01

Currently, the heat transfer equation used in the rotary combustion engine (RCE) simulation model is taken from piston engine studies. These relations have been empirically developed by the experimental input coming from piston engines whose geometry differs considerably from that of the RCE. The objective of this work was to derive equations to estimate heat transfer coefficients in the combustion chamber of an RCE. This was accomplished by making detailed temperature and pressure measurements in a direct injection stratified charge (DISC) RCE under a range of conditions. For each specific measurement point, the local gas velocity was assumed equal to the local rotor tip speed. Local physical properties of the fluids were then calculated. Two types of correlation equations were derived and are described in this paper. The first correlation expresses the Nusselt number as a function of the Prandtl number, Reynolds number, and characteristic temperature ratio; the second correlation expresses the forced convection heat transfer coefficient as a function of fluid temperature, pressure and velocity.

To what extent can charge localization influence electron injection efficiency at graphene-porphyrin interfaces?

KAUST Repository

Parida, Manas R.

2015-04-28

Controlling the electron transfer process at donor- acceptor interfaces is a research direction that has not yet seen much progress. Here, with careful control of the charge localization on the porphyrin macrocycle using β -Cyclodextrin as an external cage, we are able to improve the electron injection efficiency from cationic porphyrin to graphene carboxylate by 120% . The detailed reaction mechanism is also discussed.

High-performance serial block-face SEM of nonconductive biological samples enabled by focal gas injection-based charge compensation.

Science.gov (United States)

Deerinck, T J; Shone, T M; Bushong, E A; Ramachandra, R; Peltier, S T; Ellisman, M H

2018-05-01

A longstanding limitation of imaging with serial block-face scanning electron microscopy is specimen surface charging. This charging is largely due to the difficulties in making biological specimens and the resins in which they are embedded sufficiently conductive. Local accumulation of charge on the specimen surface can result in poor image quality and distortions. Even minor charging can lead to misalignments between sequential images of the block-face due to image jitter. Typically, variable-pressure SEM is used to reduce specimen charging, but this results in a significant reduction to spatial resolution, signal-to-noise ratio and overall image quality. Here we show the development and application of a simple system that effectively mitigates specimen charging by using focal gas injection of nitrogen over the sample block-face during imaging. A standard gas injection valve is paired with a precisely positioned but retractable application nozzle, which is mechanically coupled to the reciprocating action of the serial block-face ultramicrotome. This system enables the application of nitrogen gas precisely over the block-face during imaging while allowing the specimen chamber to be maintained under high vacuum to maximise achievable SEM image resolution. The action of the ultramicrotome drives the nozzle retraction, automatically moving it away from the specimen area during the cutting cycle of the knife. The device described was added to a Gatan 3View system with minimal modifications, allowing high-resolution block-face imaging of even the most charge prone of epoxy-embedded biological samples. © 2017 The Authors Journal of Microscopy © 2017 Royal Microscopical Society.

Measurements of Lunar Dust Charging Properties by Electron Impact

Science.gov (United States)

Abbas, Mian M.; Tankosic, Dragana; Craven, Paul D.; Schneider, Todd A.; Vaughn, Jason A.; LeClair, Andre; Spann, James F.; Norwood, Joseph K.

2009-01-01

Dust grains in the lunar environment are believed to be electrostatically charged predominantly by photoelectric emissions resulting from solar UV radiation on the dayside, and on the nightside by interaction with electrons in the solar wind plasma. In the high vacuum environment on the lunar surface with virtually no atmosphere, the positive and negative charge states of micron/submicron dust grains lead to some unusual physical and dynamical dust phenomena. Knowledge of the electrostatic charging properties of dust grains in the lunar environment is required for addressing their hazardous effect on the humans and mechanical systems. It is well recognized that the charging properties of individual small micron size dust grains are substantially different from the measurements on bulk materials. In this paper we present the results of measurements on charging of individual Apollo 11 and Apollo 17 dust grains by exposing them to mono-energetic electron beams in the 10-100 eV energy range. The charging/discharging rates of positively and negatively charged particles of approx. 0.1 to 5 micron radii are discussed in terms of the sticking efficiencies and secondary electron yields. The secondary electron emission process is found to be a complex and effective charging/discharging mechanism for incident electron energies as low as 10-25 eV, with a strong dependence on particle size. Implications of the laboratory measurements on the nature of dust grain charging in the lunar environment are discussed.

Modulating the line shape of magnetoconductance by varying the charge injection in polymer light-emitting diodes

Directory of Open Access Journals (Sweden)

Nidya Chitraningrum

2018-02-01

Full Text Available We fabricate the phenyl-substituted poly(p-phenylene vinylene copolymer (super yellow, SY-PPV-based polymer light-emitting diodes (PLEDs with different device architectures to modulate the injection of opposite charge carriers and investigate the corresponding magnetoconductance (MC responses. At the first glance, we find that all PLEDs exhibit the positive MC responses. By applying the mathematical analysis to fit the curves with two empirical equations of a non-Lorentzian and a Lorentzian function, we are able to extract the hidden negative MC component from the positive MC curve. We attribute the growth of the negative MC component to the reduced interaction of the triplet excitons with charges to generate the free charge carriers as modulated by the applied magnetic field, known as the triplet exciton-charge reaction, by analyzing MC responses for PLEDs of the charge-unbalanced and hole-blocking device configurations. The negative MC component causes the broadening of the line shape in MC curves.

Effect of liposomes on rheological and syringeability properties of hyaluronic acid hydrogels intended for local injection of drugs.

Science.gov (United States)

El Kechai, Naila; Bochot, Amélie; Huang, Nicolas; Nguyen, Yann; Ferrary, Evelyne; Agnely, Florence

2015-06-20

The aim of this work was to thoroughly study the effect of liposomes on the rheological and the syringeability properties of hyaluronic acid (HA) hydrogels intended for the local administration of drugs by injection. Whatever the characteristics of the liposomes added (neutral, positively or negatively charged, with a corona of polyethylene glycol chains, size), the viscosity and the elasticity of HA gels increased in a lipid concentration-dependent manner. Indeed, liposomes strengthened the network formed by HA chains due to their interactions with this polymer. The nature and the resulting effects of these interactions depended on liposome composition and concentration. The highest viscosity and elasticity were observed with liposomes covered by polyethylene glycol chains while neutral liposomes displayed the lowest effect. Despite their high viscosity at rest, all the formulations remained easily injectable through needles commonly used for local injections thanks to the shear-thinning behavior of HA gels. The present study demonstrates that rheological and syringeability tests are both necessary to elucidate the behavior of such systems during and post injection. In conclusion, HA liposomal gels appear to be a promising and versatile formulation platform for a wide range of applications in local drug delivery when an injection is required. Copyright © 2015 Elsevier B.V. All rights reserved.

Spin properties of charged Mn-doped quantum dota)

Science.gov (United States)

Besombes, L.; Léger, Y.; Maingault, L.; Mariette, H.

2007-04-01

The optical properties of individual quantum dots doped with a single Mn atom and charged with a single carrier are analyzed. The emission of the neutral, negatively and positively charged excitons coupled with a single magnetic atom (Mn) are observed in the same individual quantum dot. The spectrum of the charged excitons in interaction with the Mn atom shows a rich pattern attributed to a strong anisotropy of the hole-Mn exchange interaction slightly perturbed by a small valence-band mixing. The anisotropy in the exchange interaction between a single magnetic atom and a single hole is revealed by comparing the emission of a charged Mn-doped quantum dot in longitudinal and transverse magnetic field.

Long fiber polymer composite property calculation in injection molding simulation

Science.gov (United States)

Jin, Xiaoshi; Wang, Jin; Han, Sejin

2013-05-01

Long fiber filled polymer composite materials have attracted a great attention and usage in recent years. However, the injection and compression molded long fiber composite materials possess complex microstructures that include spatial variations in fiber orientation and length. This paper presents the recent implemented anisotropic rotary diffusion - reduced strain closure (ARD-RSC) model for predicting fiber orientation distribution[1] and a newly developed fiber breakage model[2] for predicting fiber length distribution in injection and compression molding simulation, and Eshelby-Mori-Tanaka model[3,4] with fiber-matrix de-bonding model[5] have been implemented to calculate the long fiber composite property distribution with predicted fiber orientation and fiber length distributions. A validation study on fiber orientation, fiber breakage and mechanical property distributions are given with injection molding process simulation.

Charge-transfer properties in the gas electron multiplier

International Nuclear Information System (INIS)

Han, Sanghyo; Kim, Yongkyun; Cho, Hyosung

2004-01-01

The charge transfer properties of a gas electron multiplier (GEM) were systematically investigated over a broad range of electric field configurations. The electron collection efficiency and the charge sharing were found to depend on the external fields, as well as on the GEM voltage. The electron collection efficiency increased with the collection field up to 90%, but was essentially independent of the drift field strength. A double conical GEM has a 10% gain increase with time due to surface charging by avalanche ions whereas this effect was eliminated with the cylindrical GEM. The positive-ion feedback is also estimated. (author)

Calibration by precise charge injection of a sub-detector of CMS; Calibration par injection de charge du calorimetre electromagnetique de CMS

Energy Technology Data Exchange (ETDEWEB)

Yong-Wook Baek

2001-01-26

This thesis was carried out within the framework of the international collaboration which has the responsibility of the experience CMS (Compact Muon Solenoid) on LHC, at CERN. The physics of the fundamental particles which will be explored by this experiment is described within the standard model. The configuration of sub-detector of CMS is briefly described, with a particular weight on the read-out chain of the electromagnetic calorimeter. The work carried out to calibrate this chain by a precise charge injection at the input of preamplifiers is described. The 4 integrated circuits CTRL, TPLS, DAC, and injector which will constitute the components of this chain of calibration are described. The circuit of injection, which is the main circuit in this project, was imagined and developed at the laboratory in DMILL technology. This injector generates a signal which has a form identical to the signal of the detector. The measurements on the linearity of the injectors are presented. In order to know its behavior under real conditions (flow of neutrons {approx} 2 x 10{sup 13} neutrons/cm{sup 2}/10 years) where this circuit is installed in detector CMS, we submitted the prototypes of injector to irradiation and the results are summarized. The research and development on this circuit produced an integrated circuit hardened to irradiations, whose variation of slope is lower than 0.25% for an integrated of 2 x 10{sup 13} neutrons/cm{sup 2} and indestructible under 10{sup 15} neutrons/cm{sup 2}. This circuit has satisfactory qualities to be assembled on the electronic card which will treat the data of calorimeter ECAL of CMS. (author)

Charge transport in organic semiconductors.

Science.gov (United States)

Bässler, Heinz; Köhler, Anna

2012-01-01

Modern optoelectronic devices, such as light-emitting diodes, field-effect transistors and organic solar cells require well controlled motion of charges for their efficient operation. The understanding of the processes that determine charge transport is therefore of paramount importance for designing materials with improved structure-property relationships. Before discussing different regimes of charge transport in organic semiconductors, we present a brief introduction into the conceptual framework in which we interpret the relevant photophysical processes. That is, we compare a molecular picture of electronic excitations against the Su-Schrieffer-Heeger semiconductor band model. After a brief description of experimental techniques needed to measure charge mobilities, we then elaborate on the parameters controlling charge transport in technologically relevant materials. Thus, we consider the influences of electronic coupling between molecular units, disorder, polaronic effects and space charge. A particular focus is given to the recent progress made in understanding charge transport on short time scales and short length scales. The mechanism for charge injection is briefly addressed towards the end of this chapter.

Performance of a supercharged direct-injection stratified-charge rotary combustion engine

Science.gov (United States)

Bartrand, Timothy A.; Willis, Edward A.

1990-01-01

A zero-dimensional thermodynamic performance computer model for direct-injection stratified-charge rotary combustion engines was modified and run for a single rotor supercharged engine. Operating conditions for the computer runs were a single boost pressure and a matrix of speeds, loads and engine materials. A representative engine map is presented showing the predicted range of efficient operation. After discussion of the engine map, a number of engine features are analyzed individually. These features are: heat transfer and the influence insulating materials have on engine performance and exhaust energy; intake manifold pressure oscillations and interactions with the combustion chamber; and performance losses and seal friction. Finally, code running times and convergence data are presented.

Density functional theory calculations of charge transport properties ...

Indian Academy of Sciences (India)

ZIRAN CHEN

2017-08-04

Aug 4, 2017 ... properties of 'plate-like' coronene topological structures ... Keywords. Organic semiconductors; density functional theory; charge carrier mobility; ambipolar transport; ..... nology Department of Sichuan Province (Grant Number.

The computation of properties of injection-moulded products

NARCIS (Netherlands)

Douven, L.F.A.; Baaijens, F.P.T.; Meijer, H.E.H.

1995-01-01

Injection moulding is a flexible production technique for the manufacture of complex shaped, thin walled polymer products that require minimal finishing. During processing, the polymer experiences a complex deformation and temperature history that affects the final properties of the product. In a

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

KAUST Repository

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

2018-01-01

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

Plasma dynamics near an earth satellite and neutralization of its electric charge during electron beam injection into the ionosphere

International Nuclear Information System (INIS)

Fedorov, V.A.

2000-01-01

A study is made of the dynamics of the ionospheric plasma in the vicinity of an earth satellite injecting an electron beam. The time evolution of the electric charge of the satellite is determined. The electric potential of the satellite is found to be well below the beam-cutoff potential. It is shown that, under conditions typical of active experiments in space, the plasma electrons are capable of neutralizing the satellite's charge

Efficient charge injection in p-type polymer field-effect transistors with low-cost molybdenum electrodes through V2O5 interlayer.

Science.gov (United States)

Baeg, Kang-Jun; Bae, Gwang-Tae; Noh, Yong-Young

2013-06-26

Here we report high-performance polymer OFETs with a low-cost Mo source/drain electrode by efficient charge injection through the formation of a thermally deposited V2O5 thin film interlayer. A thermally deposited V2O5 interlayer is formed between a regioregular poly(3-hexylthiophene) (rr-P3HT) or a p-type polymer semiconductor containing dodecyl-substituted thienylenevinylene (TV) and dodecylthiophene (PC12TV12T) and the Mo source/drain electrode. The P3HT or PC12TV12T OFETs with the bare Mo electrode exhibited lower charge carrier mobility than those with Au owing to a large barrier height for hole injection (0.5-1.0 eV). By forming the V2O5 layer, the P3HT or PC12TV12T OFETs with V2O5 on the Mo electrode exhibited charge carrier mobility comparable to that of a pristine Au electrode. Best P3HT or PC12TV12T OFETs with 5 nm thick V2O5 on Mo electrode show the charge carrier mobility of 0.12 and 0.38 cm(2)/(V s), respectively. Ultraviolet photoelectron spectroscopy results exhibited the work-function of the Mo electrode progressively changed from 4.3 to 4.9 eV with an increase in V2O5 thickness from 0 to 5 nm, respectively. Interestingly, the V2O5-deposited Mo exhibits comparable Rc to Au, which mainly results from the decreased barrier height for hole carrier injection from the low-cost metal electrode to the frontier molecular orbital of the p-type polymer semiconductor after the incorporation of the transition metal oxide hole injection layer, such as V2O5. This enables the development of large-area, low-cost electronics with the Mo electrodes and V2O5 interlayer.

Effects of noble-metal ion implantation on corrosion inhibition and charge injection capability of surgical Ti and Ti-6Al-4V

International Nuclear Information System (INIS)

Lee, I.S.

1989-01-01

Studies are described involving effects of noble-metal ion implantation on corrosion inhibition and charge injection capabilities of surgical Ti and Ti-6Al-4V. With surgical alloys, harmful biological responses are principally due to the type and quantity of metal ions released by the corrosion process. One approach to improve long-term biological performance involves surface modifications to significantly reduce degradation rates. With regard to surface-modifications, one of the most effective methods is through ion implantation. Results are presented for ion-implanted Au, Rh, and Ir. For the static in vitro corrosion properties, the noble-metal ion implanted Ti-6Al-4V and commercially-pure (CP) Ti were investigated in non-passivating acid and passivating saline solutions. It was postulated that during the early stages of corrosion (or during a corrosion pretreatment) the implanted noble-metal would enrich at the surface and significantly reduce subsequent corrosion rates. The observed behavior for the Ir and Rh implanted materials appeared to follow the postulated mechanism, with both initial and time-dependent improvements in corrosion resistance. However, the Au implanted material yielded early benefits, but the enhanced corrosion resistance deteriorated with time. X-ray photoelectron spectroscopy (XPS) analysis indicated that the implanted Au atoms remained as pure metallic Au, while the Ir and Rh atoms were in some oxide state, which gave the good adhesion of the Ir or Rh enriched surface to the Ti substrate. For a stimulating neural electrode, the charge density should be as large as possible to provide adequate stimulation of the nervous system while allowing for miniaturization of the electrode. Activated Ir has been known as having the highest charge injection capability of any material known

Charge exchange measurements of MHD activity during neutral beam injection in the Princeton Large Torus and the Poloidal Divertor Experiment

International Nuclear Information System (INIS)

Goldston, R.J.; Kaita, R.; Beiersdorfer, P.; Gammel, G.; Herndon, D.L.; McCune, D.C.; Meyerhofer, D.D.

1987-01-01

The horizontally scanning, multi-angle charge exchange analysers on the Princeton Large Torus (PLT) and the Poloidal Divertor Experiment (PDX) were used to study the effects of MHD activity on the background ion distribution function and on the beam ion slowing-down process during high power neutral injection. Sawtooth oscillations were observed in the fast ion flux on PLT and PDX, and measurements with neutral beams providing local neutral density enhancement indicated that the ions were transported radially when these events occurred. With near-perpendicular injection in PDX, at the lower toroidal fields necessary to maximize the plasma beta, repetitive bursts of greatly enhanced charge exchange flux were observed. These were associated with the 'fishbone' MHD instability, and a substantial depletion of the perpendicular slowing-down spectrum below the injection energy was seen. A simple phenomenological model for this loss mechanism was developed, and its use in simulation codes has been successful in providing good agreement with the experimental data. The behaviour and characteristics of this model are well matched by direct theoretical calculations. (author)

Charge-exchange measurements of MHD activity during neutral beam injection in the Princeton Large Torus and the Poloidal Divertor Experiment

International Nuclear Information System (INIS)

Goldston, R.J.; Kaita, R.; Beiersdorfer, P.; Gammel, G.; Herndon, D.L.; McCune, D.C.; Meyerhofer, D.D.

1986-07-01

The horizontally scanning, multiangle charge-exchange analyzers on the Princeton Large Torus (PLT) and the Poloidal Divertor Experiment (PDX) were used to study the effects of MHD activity on the background ion distribution function and on the beam ion slowing-down process during high-power neutral injection. Sawtooth oscillations were observed in the fast ion flux on PLT and PDX, and measurements with neutral beams providing local neutral density enhancement indicate that ions are transported radially when these events occur. With near-perpendicular injection in PDX, at the lower toroidal fields necessary to maximize beta, rapid, repetitive bursts of greatly enhanced charge-exchange flux were observed. These are associated with the ''fishbone'' MHD instability, and a substantial depletion of the perpendicular slowing-down spectrum below the injection energy was seen. A simple phenomenological model for this loss mechanism was developed, and its use in simulation codes has been successful in providing good agreement with the data. The behavior and characteristics of this model are well matched by the direct theoretical calculations

Improvement of tokamak performance by injection of electrons

International Nuclear Information System (INIS)

Ono, Masayuki.

1992-12-01

Concepts for improving tokamak performance by utilizing injection of hot electrons are discussed. Motivation of this paper is to introduce the research work being performed in this area and to refer the interested readers to the literature for more detail. The electron injection based concepts presented here have been developed in the CDX, CCT, and CDX-U tokamak facilities. The following three promising application areas of electron injection are described here: 1. Non-inductive current drive, 2. Plasma preionization for tokamak start-up assist, and 3. Charging-up of tokamak flux surfaces for improved plasma confinement. The main motivation for the dc-helicity injection current drive is in its efficiency that, in theory, is independent of plasma density. This property makes it attractive for driving currents in high density reactor plasmas

Increased charge storage capacity of titanium nitride electrodes by deposition of boron-doped nanocrystalline diamond films

DEFF Research Database (Denmark)

Meijs, Suzan; McDonald, Matthew; Sørensen, Søren

2015-01-01

The aim of this study was to investigate the feasibility of depositing a thin layer of boron-doped nanocrystalline diamond (B-NCD) on titanium nitride (TiN) coated electrodes and the effect this has on charge injection properties. The charge storage capacity increased by applying the B-NCD film...

Sensitized charge carrier injection into organic crystals studied by isotope effects in weak magnetic fields

International Nuclear Information System (INIS)

Bube, W.; Michel-Beyerle, M.E.; Haberkorn, R.; Steffens, E.

1977-01-01

The magnetic field (H approximately 50 Oe) dependence of the rhodamine sensitized triplet exciton density in anthracene crystals is influenced by isotopic substitution. This confirms the hyperfine interaction as mechanism explaining the change of the spin multiplicity in the initially formed singlet state of the radical pair. The isotope effect occurs in the sensitizing dye ( 14 N/ 15 N) rather than at the molecular site of the injected charge within the crystal. This can be understood in terms of the high hopping frequency of the charge carriers as compared to the time constant of the hyperfine induced singlet-triplet transition. Since the dye molecules adsorb in an oriented fashion, the angular dependence of the magnetic field modulation of the triplet exciton density can be interpreted without assuming any additional interactions. (Auth.)

Space charge and magnet error simulations for the SNS accumulator ring

International Nuclear Information System (INIS)

Beebe-Wang, J.; Fedotov, A.V.; Wei, J.; Machida, S.

2000-01-01

The effects of space charge forces and magnet errors in the beam of the Spallation Neutron Source (SNS) accumulator ring are investigated. In this paper, the focus is on the emittance growth and halo/tail formation in the beam due to space charge with and without magnet errors. The beam properties of different particle distributions resulting from various injection painting schemes are investigated. Different working points in the design of SNS accumulator ring lattice are compared. The simulations in close-to-resonance condition in the presence of space charge and magnet errors are presented. (author)

Charge-order driven multiferroic and magneto-dielectric properties of rare earth manganates

International Nuclear Information System (INIS)

Serrao, Claudy Rayan; Sahu, Jyoti Ranjan; Ghosh, Anirban

2010-01-01

Charge-order driven magnetic ferroelectricity is shown to occur in several rare earth manganates of the general formula, Ln 1-x A x MnO 3 (Ln rare earth, A = alkaline earth). Charge-ordered manganates exhibit dielectric constant anomalies around the charge-ordering or the antiferromagnetic transition temperature. Magnetic fields have a marked effect on the dielectric properties of these compounds, indicating the presence of coupling between the magnetic and electrical order parameters. Magneto-dielectric properties are retained in small particles of the manganates. The observation of magneto-ferroelectricity in these manganates is in accordance with theoretical predictions. (author)

Transport and Fatigue Properties of Ferroelectric Polymer P(VDF-TrFE) For Nonvolatile Memory Applications

KAUST Repository

Hanna, Amir

2012-01-01

injection and transport are believed to affect various properties of ferroelectric films such as remnant polarization values and polarization fatigue behavior.. Thus, this thesis aims to study charge injection in P(VDF-TrFE) and its transport properties as a

Charge imbalance

International Nuclear Information System (INIS)

Clarke, J.

1981-01-01

This article provides a long theoretical development of the main ideas of charge imbalance in superconductors. Concepts of charge imbalance and quasiparticle charge are introduced, especially in regards to the use of tunnel injection in producing and detecting charge imbalance. Various mechanisms of charge relaxation are discussed, including inelastic scattering processes, elastic scattering in the presence of energy-gap anisotropy, and various pair-breaking mechanisms. In each case, present theories are reviewed in comparison with experimental data

Charge Injection and Transport in Organic Nanofibers

DEFF Research Database (Denmark)

Kjelstrup-Hansen, Jakob; Bøggild, Peter; Rubahn, H. G.

2007-01-01

the injection barrier height equal to the difference between the metal electrode work function and the HOMO energy level of the organic semiconductor. Semiquantitative modeling suggests that the weak temperature dependence is due to injection into a distribution of states rather than into a single energy level...

Optimization of the charge-carrier injection in organic light-emitting diodes; Optimierung der Ladungstraegerinjektion in organische Leuchtdioden

Energy Technology Data Exchange (ETDEWEB)

Krause, Ralf

2009-07-01

Nowadays based on resource shortage and climate warming there is a big interest in the use of power-saving lighting sources. Therefore the research on white organic light emitting devices (OLEDs) has gained importance during the last years. To obtain high power efficiencies in OLEDs it is necessary to provide low driving voltages. That can be realised by the use of doped transport layers, in which donors and acceptors are coevaporated with organic transport materials. In this thesis I discuss novel p-type and n-type doping materials for small organic molecules which decrease the ohmic loss in organic transport layers used in OLEDs. This reduction of the resistance is caused by an increase of the intrinsic charge carrier density and therefore an increase of the conductivity. First single layer devices are used to analyse the properties of potential doping materials by varying the doping concentration. The tested p-doping materials are commercially available metal oxides (MoO{sub 3} and Re{sub 2}O{sub 7}) and metal-organic complexes. Both metal oxides show a strong conductivity improvement of up to 7 orders of magnitude. The investigated n-doping materials are alkali salts, metal-organic and organic complexes. Among the alkali salts Cs{sub 2}CO{sub 3} is the best material in test with a conductivity enhancement of up to 7 orders of magnitude. For this material class I focused on the question whether the metal cation or the organic anion causes the doping effect. Using similar Caesium salts differently strong doping effects were obtained. Therefore I came to the conclusion that beside the metal cation also the anion plays a role for the doping effect. Secondly I performed a series of multilayer devices for two doping materials (Re{sub 2}O{sub 7} as acceptor and Cs{sub 2}CO{sub 3} as donor) to separate the transport and injection enhancement. The results show that a doped transport layer improves the hole or electron injection into an undoped material by several orders

Inferring Fault Frictional and Reservoir Hydraulic Properties From Injection-Induced Seismicity

Science.gov (United States)

Jagalur-Mohan, Jayanth; Jha, Birendra; Wang, Zheng; Juanes, Ruben; Marzouk, Youssef

2018-02-01

Characterizing the rheological properties of faults and the evolution of fault friction during seismic slip are fundamental problems in geology and seismology. Recent increases in the frequency of induced earthquakes have intensified the need for robust methods to estimate fault properties. Here we present a novel approach for estimation of aquifer and fault properties, which combines coupled multiphysics simulation of injection-induced seismicity with adaptive surrogate-based Bayesian inversion. In a synthetic 2-D model, we use aquifer pressure, ground displacements, and fault slip measurements during fluid injection to estimate the dynamic fault friction, the critical slip distance, and the aquifer permeability. Our forward model allows us to observe nonmonotonic evolutions of shear traction and slip on the fault resulting from the interplay of several physical mechanisms, including injection-induced aquifer expansion, stress transfer along the fault, and slip-induced stress relaxation. This interplay provides the basis for a successful joint inversion of induced seismicity, yielding well-informed Bayesian posterior distributions of dynamic friction and critical slip. We uncover an inverse relationship between dynamic friction and critical slip distance, which is in agreement with the small dynamic friction and large critical slip reported during seismicity on mature faults.

Study of static properties of magnetron-type space charges

International Nuclear Information System (INIS)

Delcroix, Jean-Loup

1953-01-01

This research thesis reports an in-depth analysis of physical properties of static regimes to address the issue of space charges. This theoretical study of the Hull magnetron is followed by the description of experiments on the Hull magnetron which highlight transitions between the different regimes. Then, another theoretical approach aims at generalising the magnetron theory, based on other types of magnetron theory (general equations of magnetron-type space charges, inverted Hull magnetron theory, circular field magnetron theory)

Simulation study of signal formation in position sensitive planar p-on-n silicon detectors after short range charge injection

International Nuclear Information System (INIS)

Peltola, T.; Eremin, V.; Verbitskaya, E.; Härkönen, J.

2017-01-01

Segmented silicon detectors (micropixel and microstrip) are the main type of detectors used in the inner trackers of Large Hadron Collider (LHC) experiments at CERN. Due to the high luminosity and eventual high fluence of energetic particles, detectors with fast response to fit the short shaping time of 20–25 ns and sufficient radiation hardness are required. Charge collection measurements carried out at the Ioffe Institute have shown a reversal of the pulse polarity in the detector response to short-range charge injection. Since the measured negative signal is about 30–60% of the peak positive signal, the effect strongly reduces the CCE even in non-irradiated detectors. For further investigation of the phenomenon the measurements have been reproduced by TCAD simulations. As for the measurements, the simulation study was applied for the p-on-n strip detectors similar in geometry to those developed for the ATLAS experiment and for the Ioffe Institute designed p-on-n strip detectors with each strip having a window in the metallization covering the p + implant, allowing the generation of electron-hole pairs under the strip implant. Red laser scans across the strips and the interstrip gap with varying laser diameters and Si-SiO 2 interface charge densities ( Q f ) were carried out. The results verify the experimentally observed negative response along the scan in the interstrip gap. When the laser spot is positioned on the strip p + implant the negative response vanishes and the collected charge at the active strip increases respectively. The simulation results offer a further insight and understanding of the influence of the oxide charge density in the signal formation. The main result of the study is that a threshold value of Q f , that enables negligible losses of collected charges, is defined. The observed effects and details of the detector response for different charge injection positions are discussed in the context of Ramo's theorem.

Simulation study of signal formation in position sensitive planar p-on-n silicon detectors after short range charge injection

Science.gov (United States)

Peltola, T.; Eremin, V.; Verbitskaya, E.; Härkönen, J.

2017-09-01

Segmented silicon detectors (micropixel and microstrip) are the main type of detectors used in the inner trackers of Large Hadron Collider (LHC) experiments at CERN. Due to the high luminosity and eventual high fluence of energetic particles, detectors with fast response to fit the short shaping time of 20-25 ns and sufficient radiation hardness are required. Charge collection measurements carried out at the Ioffe Institute have shown a reversal of the pulse polarity in the detector response to short-range charge injection. Since the measured negative signal is about 30-60% of the peak positive signal, the effect strongly reduces the CCE even in non-irradiated detectors. For further investigation of the phenomenon the measurements have been reproduced by TCAD simulations. As for the measurements, the simulation study was applied for the p-on-n strip detectors similar in geometry to those developed for the ATLAS experiment and for the Ioffe Institute designed p-on-n strip detectors with each strip having a window in the metallization covering the p+ implant, allowing the generation of electron-hole pairs under the strip implant. Red laser scans across the strips and the interstrip gap with varying laser diameters and Si-SiO2 interface charge densities (Qf) were carried out. The results verify the experimentally observed negative response along the scan in the interstrip gap. When the laser spot is positioned on the strip p+ implant the negative response vanishes and the collected charge at the active strip increases respectively. The simulation results offer a further insight and understanding of the influence of the oxide charge density in the signal formation. The main result of the study is that a threshold value of Qf, that enables negligible losses of collected charges, is defined. The observed effects and details of the detector response for different charge injection positions are discussed in the context of Ramo's theorem.

Multifunctional hybrid diode: Study of photoresponse, high responsivity, and charge injection mechanisms

Science.gov (United States)

Singh, Jitendra; Singh, R. G.; Gautam, Subodh K.; Singh, Fouran

2018-05-01

A multifunctional hybrid heterojunction diode is developed on porous silicon and its current density-voltage characteristics reveal a good rectification ratio along with other superior parameters such as ideality factor, barrier height and series resistance. The diode also functions as an efficient photodiode to manifest high photosensitivity with high responsivity under illumination with broadband solar light, UV light, and green light. The diode is also carefully scrutinized for its sensitivity and repeatability over many cycles under UV and green light and is found to have a quick response and extremely fast recovery times. The notable responsivity is attributed to the generation of high density of excitons in the depletion region by the absorption of incident photons and their separation by an internal electric field besides an additional photocurrent due to the charging of polymer chains. The mechanisms of generation, injection and transport of charge carriers are explained by developing a schematic energy band diagram. The transport phenomenon of carriers is further investigated from room temperature down to a very low temperature of 10 K. An Arrhenius plot is made to determine the Richardson constant. Various diode parameters as mentioned above are also determined and the dominance of the transport mechanism of charge carriers in different temperature regimes such as diffusion across the junction and/or quantum tunneling through the barriers are explained. The developed multifunction heterojunction hybrid diodes have implications for highly sensitive photodiodes in the UV and visible range of electromagnetic spectrum that can be very promising for efficient optoelectronic devices.

Study of charge transport in composite blend of P3HT and PCBM

Science.gov (United States)

Kumar, Manoj; Kumar, Sunil; Upadhyaya, Aditi; Yadav, Anjali; Gupta, Saral K.; Singh, Amarjeet

2018-05-01

Poly (3-hexylthiophene-2,5diyl) (P3HT) as donor and [6,6]-phenyl C61 butyric acid methyl ester (PCBM) as acceptor are mostly used as active medium in polymeric electronic device. In this paper we have prepare the P3HT - PCBM based bulk hetero junction thin films by spin coating technique. The charge transport properties of P3HT:PCBM blends are investigated by the current-voltage measurements using Ag as an electron injecting electrode and ITO as a hole injecting contact. The current density v/s voltage relationships are analyzed in the backdrop of Schottky and Space charge limited current model.

Electron beam injection during active experiments. I - Electromagnetic wave emissions

Science.gov (United States)

Winglee, R. M.; Kellogg, P. J.

1990-01-01

The wave emissions produced in Echo 7 experiment by active injections of electron beams were investigated to determine the properties of the electromagnetic and electrostatic fields for both the field-aligned and cross-field injection in such experiments and to evaluate the sources of free energy and relative efficiencies for the generation of the VLF and HF emissions. It is shown that, for typical beam energies in active experiments, electromagnetic effects do not substantially change the bulk properties of the beam, spacecraft charging, and plasma particle acceleration. Through simulations, beam-generated whistlers; fundamental z-mode and harmonic x-mode radiation; and electrostatic electron-cyclotron, upper-hybrid, Langmuir, and lower-hybrid waves were identified. The characteristics of the observed wave spectra were found to be sensitive to both the ratio of the electron plasma frequency to the cyclotron frequency and the angle of injection relative to the magnetic field.

Tensile properties and microstructure of helium-injected and reactor-irradiated V-20 Ti

International Nuclear Information System (INIS)

Tanaka, M.P.; Bloom, E.E.; Horak, J.A.

1981-01-01

Mechanical properties and microstructure of vanadium-20% titanium were examined following helium-injection and reactor irradiation. Helium was injected at ambient temperature to concentrations of 90 and 200 at. ppM; neutron irradiation was at 400, 575, 625, and 700 0 C to fluence of 3 x 10 26 n/m 2 , E > 0.1 MeV. Cavities representing negligible volume swelling were observed in all helium-injected specimens. Degradation of mechanical properties, especially loss of ductility due to helium, occurred at temperatures of 625 and 700 0 C. The levels of helium produced in the fusion spectrum can be expected to alter the response of vanadium alloys from that observed in fast reactor irradiations

Tensile properties and microstructure of helium-injected and reactor-irradiated V-20 Ti

Energy Technology Data Exchange (ETDEWEB)

Tanaka, M.P.; Bloom, E.E.; Horak, J.A.

1981-01-01

Mechanical properties and microstructure of vanadium-20% titanium were examined following helium-injection and reactor irradiation. Helium was injected at ambient temperature to concentrations of 90 and 200 at. ppM; neutron irradiation was at 400, 575, 625, and 700/sup 0/C to fluence of 3 x 10/sup 26/ n/m/sup 2/, E > 0.1 MeV. Cavities representing negligible volume swelling were observed in all helium-injected specimens. Degradation of mechanical properties, especially loss of ductility due to helium, occurred at temperatures of 625 and 700/sup 0/C. The levels of helium produced in the fusion spectrum can be expected to alter the response of vanadium alloys from that observed in fast reactor irradiations.

Semiconductor nanoparticles with spatial separation of charge carriers: synthesis and optical properties

International Nuclear Information System (INIS)

Vasiliev, Roman B; Dirin, Dmitry N; Gaskov, Alexander M

2011-01-01

The results of studies on core/shell semiconductor nanoparticles with spatial separation of photoexcited charge carriers are analyzed and generalized. Peculiarities of the electronic properties of semiconductor/semiconductor heterojunctions formed inside such particles are considered. Data on the effect of spatial separation of charge carriers on the optical properties of nanoparticles including spectral shifts of the exciton bands, absorption coefficients and electron–hole pair recombination times are presented. Methods of synthesis of core/shell semiconductor nanoparticles in solutions are discussed. Specific features of the optical properties of anisotropic semiconductor nanoparticles with the semiconductor/semiconductor junctions are noted. The bibliography includes 165 references.

Acid slag injection into the blast furnace tuyere zone

Energy Technology Data Exchange (ETDEWEB)

Tervola, K.; Haerkki, J.

1996-12-31

The possibility of acid slag injection and its effect on the slag formation and on the melting behaviour of the charge materials are studied in the present work. The work is partly based on the literature evaluating the slag formation, slag properties and the basic slag injection. The possibility of acid slag injection is first examined by studying changes in the composition of the primary slag if the share of the acid slag component (Kostamus pellet/RR) of the charge material is lowered. Phase diagrams and viscosity charts are used to evaluate the viscosity, and solidus/liquids temperature in the slag phase. The share of the slag phase of the pellet is evaluated by calculating the amount of the acid slag injection. The injection rate of some injectants is also examined. The primary slag formed of the sinter and the coke ash is in liquid form and its viscosity is close to the viscosity of the blast furnace slag. It is possible that the liquid slag phase can be formed in the blast furnace without the presence of the acid pellet because the melting point and the viscosity of the slag is lowered by alkalies, sulfur and the dissolved ironoxide of the slag. If high SiO{sub 2} content materials alone are used for injection there is a risk that the slag phase of the tuyere zone becomes too viscous. Olivine and some iron containing components such as fayalite are possible injection material. More information is needed to evaluate the effect of acid slag injection on the operation of the blast furnace. (orig.) (14 refs.)

Acid slag injection into the blast furnace tuyere zone

Energy Technology Data Exchange (ETDEWEB)

Haerkki, J.; Tervola, K. [Oulu Univ. (Finland). Dept. of Process Engineering

1996-12-31

The possibility of acid slag injection and its effect on the slag formation and on the melting behaviour of the charge materials are studied in the present work. The work is partly based on the literature evaluating the slag formation, slag properties and the basic slag injection. The possibility of acid slag injection is first examined by studying changes in the composition of the primary slag if the share of the acid slag component (Kostamus pellet/RR) of the charge material is lowered. Phase diagrams and viscosity charts are used to evaluate the viscosity, and solidus/liquidus temperature in the slag phase. The share of the slag phase of the pellet is evaluated by calculating the amount of the acid slag injection. The injection rate of some injectants is also examined. The primary slag formed of the sinter and the coke ash is in liquid form and its viscosity is close to the viscosity of the blast furnace slag. It is possible that the liquid slag phase can be formed in the blast furnace without the presence of the acid pellet because the melting point and the viscosity of the slag is lowered by alkalies, sulfur and the dissolved ironoxide of the slag. If high SiO{sub 2} content materials alone are used for injection there is a risk that the slag phase of the tuyere zone becomes too viscous. Olivine and some iron containing components such as fayalite are possible injection material. More information is needed to evaluate the effect of acid slag injection on the operation of the blast furnace. (orig.) SULA 2 Research Programme; 2 refs.

Acid slag injection into the blast furnace tuyere zone

Energy Technology Data Exchange (ETDEWEB)

Haerkki, J; Tervola, K [Oulu Univ. (Finland). Dept. of Process Engineering

1997-12-31

The possibility of acid slag injection and its effect on the slag formation and on the melting behaviour of the charge materials are studied in the present work. The work is partly based on the literature evaluating the slag formation, slag properties and the basic slag injection. The possibility of acid slag injection is first examined by studying changes in the composition of the primary slag if the share of the acid slag component (Kostamus pellet/RR) of the charge material is lowered. Phase diagrams and viscosity charts are used to evaluate the viscosity, and solidus/liquidus temperature in the slag phase. The share of the slag phase of the pellet is evaluated by calculating the amount of the acid slag injection. The injection rate of some injectants is also examined. The primary slag formed of the sinter and the coke ash is in liquid form and its viscosity is close to the viscosity of the blast furnace slag. It is possible that the liquid slag phase can be formed in the blast furnace without the presence of the acid pellet because the melting point and the viscosity of the slag is lowered by alkalies, sulfur and the dissolved ironoxide of the slag. If high SiO{sub 2} content materials alone are used for injection there is a risk that the slag phase of the tuyere zone becomes too viscous. Olivine and some iron containing components such as fayalite are possible injection material. More information is needed to evaluate the effect of acid slag injection on the operation of the blast furnace. (orig.) SULA 2 Research Programme; 2 refs.

Analysis of pulsed injection for microgravity receiver tank chilldown

Science.gov (United States)

Honkonen, Scott C.; Pietrzyk, Joe R.; Schuster, John R.

The dominant heat transfer mechanism during the hold phase of a tank chilldown cycle in a low-gravity environment is due to fluid motion persistence following the charge. As compared to the single-charge per vent cycle case, pulsed injection maintains fluid motion and the associated high wall heat transfer coefficients during the hold phase. As a result, the pulsed injection procedure appears to be an attractive method for reducing the time and liquid mass required to chill a tank. However, for the representative conditions considered, no significant benefit can be realized by using pulsed injection as compared to the single-charge case. A numerical model of the charge/hold/vent process was used to evaluate the pulsed injection procedure for tank chilldown in microgravity. Pulsed injection results in higher average wall heat transfer coefficients during the hold, as compared to the single-charge case. However, these high levels were not coincident with the maximum wall-to-fluid temperature differences, as in the single-charge case. For representative conditions investigated, the charge/hold/vent process is very efficient. A slightly shorter chilldown time was realized by increasing the number of pulses.

Structural properties of water around uncharged and charged carbon nanotubes

International Nuclear Information System (INIS)

Dezfoli, Amir Reza Ansari; Mehrabian, Mozaffar Ali; Rafsanjani, Hassan Hashemipour

2013-01-01

Studying the structural properties of water molecules around the carbon nanotubes is very important in a wide variety of carbon nanotubes applications. We studied the number of hydrogen bonds, oxygen and hydrogen density distributions, and water orientation around carbon nanotubes. The water density distribution for all carbon nanotubes was observed to have the same feature. In water-carbon nanotubes interface, a high-density region of water molecules exists around carbon nanotubes. The results reveal that the water orientation around carbon nanotubes is roughly dependent on carbon nanotubes surface charge. The water molecules in close distances to carbon nanotubes were found to make an HOH plane nearly perpendicular to the water-carbon nanotubes interface for carbon nanotubes with negative surface charge. For uncharged carbon nanotubes and carbon nanotubes with positive surface charge, the HOH plane was in tangential orientation with water-carbon nanotubes interface. There was also a significant reduction in hydrogen bond of water region around carbon nanotubes as compared with hydrogen bond in bulk water. This reduction was very obvious for carbon nanotubes with positive surface charge. In addition, the calculation of dynamic properties of water molecules in water-CNT interface revealed that there is a direct relation between the number of Hbonds and self-diffusion coefficient of water molecules

Contact engineering for efficient charge injection in organic transistors with low-cost metal electrodes

Science.gov (United States)

Panigrahi, D.; Kumar, S.; Dhar, A.

2017-10-01

Controlling charge injection at the metal-semiconductor interface is very crucial for organic electronic devices in general as it can significantly influence the overall device performance. Herein, we report a facile, yet efficient contact modification approach, to enhance the hole injection efficiency through the incorporation of a high vacuum deposited TPD [N,N'-Bis(3-methylphenyl)-N,N'-diphenylbenzidine] interlayer between the electrodes and the active semiconducting layer. The device performance parameters such as mobility and on/off ratio improved significantly after the inclusion of the TPD buffer layer, and more interestingly, the devices with cost effective Ag and Cu electrodes were able to exhibit a superior device performance than the typically used Au source-drain devices. We have also observed that this contact modification technique can be even more effective than commonly used metal oxide interface modifying layers. Our investigations demonstrate the efficacy of the TPD interlayer in effectively reducing the interfacial contact resistance through the modification of pentacene energy levels, which consequently results in the substantial improvement in the device performances.

On the effects of fuel properties and injection timing in partially premixed compression ignition of low octane fuels

KAUST Repository

Naser, Nimal

2017-06-29

A better understanding on the effects of fuel properties and injection timing is required to improve the performance of advanced engines based on low temperature combustion concepts. In this work, an experimental and computational study was conducted to investigate the effects of physical and chemical kinetic properties of low octane fuels and their surrogates in partially premixed compression ignition (PPCI) engines. The main objective was to identify the relative importance of physical versus chemical kinetic properties in predicting practical fuel combustion behavior across a range of injection timings. Two fuel/surrogate pairs were chosen for comparison: light naphtha (LN) versus the primary reference fuel (PRF) with research octane number of 65 (PRF 65), and FACE (fuels for advanced combustion engines) I gasoline versus PRF 70. Two sets of parametric studies were conducted: the first varied the amount of injected fuel mass at different injection timings to match a fixed combustion phasing, and the second maintained the same injected fuel mass at each injection timing to assess resulting combustion phasing changes. Full-cycle computational fluid dynamic engine simulations were conducted by accounting for differences in the physical properties of the original and surrogate fuels, while employing identical chemical kinetics. The simulations were found to capture trends observed in the experiments, while providing details on spatial mixing and chemical reactivity for different fuels and injection timings. It was found that differences in physical properties become increasingly important as injection timing was progressively delayed from premixed conditions, and this was rationalized by analysis of mixture stratification patterns resulting from injection of fuels with different physical properties. The results suggest that accurate descriptions of both physical and chemical behavior of fuels are critical in predictive simulations of PPCI engines for a wide range of

On the effects of fuel properties and injection timing in partially premixed compression ignition of low octane fuels

KAUST Repository

Naser, Nimal; Jaasim, Mohammed; Atef, Nour; Chung, Suk-Ho; Im, Hong G.; Sarathy, Mani

2017-01-01

A better understanding on the effects of fuel properties and injection timing is required to improve the performance of advanced engines based on low temperature combustion concepts. In this work, an experimental and computational study was conducted to investigate the effects of physical and chemical kinetic properties of low octane fuels and their surrogates in partially premixed compression ignition (PPCI) engines. The main objective was to identify the relative importance of physical versus chemical kinetic properties in predicting practical fuel combustion behavior across a range of injection timings. Two fuel/surrogate pairs were chosen for comparison: light naphtha (LN) versus the primary reference fuel (PRF) with research octane number of 65 (PRF 65), and FACE (fuels for advanced combustion engines) I gasoline versus PRF 70. Two sets of parametric studies were conducted: the first varied the amount of injected fuel mass at different injection timings to match a fixed combustion phasing, and the second maintained the same injected fuel mass at each injection timing to assess resulting combustion phasing changes. Full-cycle computational fluid dynamic engine simulations were conducted by accounting for differences in the physical properties of the original and surrogate fuels, while employing identical chemical kinetics. The simulations were found to capture trends observed in the experiments, while providing details on spatial mixing and chemical reactivity for different fuels and injection timings. It was found that differences in physical properties become increasingly important as injection timing was progressively delayed from premixed conditions, and this was rationalized by analysis of mixture stratification patterns resulting from injection of fuels with different physical properties. The results suggest that accurate descriptions of both physical and chemical behavior of fuels are critical in predictive simulations of PPCI engines for a wide range of

Powder injection molding of Stellite 6 powder: Sintering, microstructural and mechanical properties

International Nuclear Information System (INIS)

Gülsoy, H. Özkan; Özgün, Özgür; Bilketay, Sezer

2016-01-01

The purpose of this study was to produce Co-based Stellite 6 superalloy components by using the method of Powder Injection Molding (PIM) and to characterize the microstructural and mechanical properties of the produced components. The experimental studies were started through the formation of feedstock by mixing Stellite 6 powder with a multicomponent binder system. Prepared feedstock was formed by utilizing powder injection molding technique. Then the molded samples were subjected to the solvent and thermal debinding processes. Different sintering cycles were applied to the raw components for the purpose of determining the optimum sintering conditions. The densities of the sintered components were determined in accordance with the Archimedes' principle. The microstructural characterization was performed through scanning electron microscope (SEM) analysis, energy dispersive spectrometry (EDS) analyses, and X-ray diffraction (XRD) analysis. Hardness measurement and tensile test were conducted in order to determine the mechanical properties. The results illustrated that the injection molded Stellite 6 components were composed of fine and equiaxed grains, plenty of carbide precipitates exhibiting homogenous distribution throughout the microstructure formed at the grain boundaries and thus the mechanical properties were considerably high.

From Process Modeling to Elastic Property Prediction for Long-Fiber Injection-Molded Thermoplastics

International Nuclear Information System (INIS)

Nguyen, Ba Nghiep; Kunc, Vlastimil; Frame, Barbara J.; Phelps, Jay; Tucker III, Charles L.; Bapanapalli, Satish K.; Holbery, James D.; Smith, Mark T.

2007-01-01

This paper presents an experimental-modeling approach to predict the elastic properties of long-fiber injection-molded thermoplastics (LFTs). The approach accounts for fiber length and orientation distributions in LFTs. LFT samples were injection-molded for the study, and fiber length and orientation distributions were measured at different locations for use in the computation of the composite properties. The current fiber orientation model was assessed to determine its capability to predict fiber orientation in LFTs. Predicted fiber orientations for the studied LFT samples were also used in the calculation of the elastic properties of these samples, and the predicted overall moduli were then compared with the experimental results. The elastic property prediction was based on the Eshelby-Mori-Tanaka method combined with the orientation averaging technique. The predictions reasonably agree with the experimental LFT data

Microcellular injection molding process for producing lightweight thermoplastic polyurethane with customizable properties

Science.gov (United States)

Ellingham, Thomas; Kharbas, Hrishikesh; Manitiu, Mihai; Scholz, Guenter; Turng, Lih-Sheng

2018-03-01

A three-stage molding process involving microcellular injection molding with core retraction and an "out-of-mold" expansion was developed to manufacture thermoplastic polyurethane into lightweight foams of varying local densities, microstructures, and mechanical properties in the same microcellular injection molded part. Two stages of cavity expansion through sequential core retractions and a third expansion in a separate mold at an elevated temperature were carried out. The densities varied from 0.25 to 0.42 g/cm3 (77% to 62% weight reduction). The mechanical properties varied as well. Cyclic compressive strengths and hysteresis loss ratios, together with the microstructures, were characterized and reported.

The Effect of Voltage Charging on the Transport Properties of Gold Nanotube Membranes.

Science.gov (United States)

Experton, Juliette; Martin, Charles R

2018-05-01

Porous membranes are used in chemical separations and in many electrochemical processes and devices. Research on the transport properties of a unique class of porous membranes that contain monodisperse gold nanotubes traversing the entire membrane thickness is reviewed here. These gold nanotubes can act as conduits for ionic and molecular transports through the membrane. Because the tubes are electronically conductive, they can be electrochemically charged by applying a voltage to the membrane. How this "voltage charging" affects the transport properties of gold nanotube membranes is the subject of this Review. Experiments showing that voltage charging can be used to reversibly switch the membrane between ideally cation- and anion-transporting states are reviewed. Voltage charging can also be used to enhance the ionic conductivity of gold nanotube membranes. Finally, voltage charging to accomplish electroporation of living bacteria as they pass through gold nanotube membranes is reviewed. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Charge transport properties in microcrystalline KDyFe(China)6

International Nuclear Information System (INIS)

Aubert, P.H.; Goubard, F.; Chevrot, C.; Tabuteau, A.

2007-01-01

Microcrystalline solid dysprosium(III) hexacyanoferrate(II) was synthesized by co-precipitation in aqueous solution. The resulting solid has been studied by Fourier transform infrared spectroscopy, X-ray analysis and solid state electrochemistry. The use of a cavity microelectrode was necessary to explore a wide range of time scale and minimize the (undesired) capacitive currents. Cyclic voltametric experiments were very helpful to understand the kinetic of charge transfer in such microstructure. A structure-properties relationship has been established from the crystallographic and the electrochemical properties. A square-scheme is presented to explain the unique electrochemical behavior of hexacyanoferrate containing dysprosium since this compound exhibits a second redox system. The solid presents an open channel-like morphology in which the motion of charged species occurs during the redox processes. Precisely, the electronic transfer is accompanied by a cation diffusion inside the microcrystalline structure. The size of these channels strongly suggests that the kinetic of charge transfer is limited by the cation transport into these structures. - Graphical abstract: Dy and Fe polyhedra packing in the cell of KDyFe(China) 6 .3.5H 2 O shows occluded water molecules and potassium ions forming a pseudohexagonal 2D sub-lattice connected to each other by diffusion channels

Adsorption properties of subtropical and tropical variable charge soils: Implications from climate change and biochar amendment

Energy Technology Data Exchange (ETDEWEB)

Xu, Ren-Kou; Qafoku, Nikolla; Van Ranst, Eric; Li, Jiu-yu; Jiang, Jun

2016-01-25

This review paper attempts to summarize the progress made in research efforts conducted over the last years to study the surface chemical properties of the tropical and subtropical soils, usually called variable charge soils, and the way they response to different management practices. The paper is composed of an introductory section that provides a brief discussion on the surface chemical properties of these soils, and five other review sections. The focus of these sections is on the evolution of surface chemical properties during the development of the variable charge properties (second section), interactions between oppositely charged particles and the resulting effects on the soil properties and especially on soil acidity (third section), the surface effects of low molecular weight organic acids sorbed to mineral surfaces and the chemical behavior of aluminum (fourth section), and the crop straw derived biochar induced changes of the surface chemical properties of these soils (fifth section). A discussion on the effect of climate change variables on the properties of the variable charge soils is included at the end of this review paper (sixth section).

Spectroscopic techniques for measuring ion diode space-charge distributions and ion source properties

Energy Technology Data Exchange (ETDEWEB)

Filuk, A B; Bailey, J E; Adams, R G [Sandia Labs., Albuquerque, NM (United States); and others

1997-12-31

The authors are using time- and space-resolved visible spectroscopy to measure applied-B ion diode dynamics on the 20 TW Particle Beam Fusion Accelerator II. Doppler broadening of fast Li atoms, as viewed parallel to the anode, is used in a charge-exchange model to obtain the Li{sup +} ion divergence within 100 {mu}m of the anode surface. The characteristic Stark/Zeeman shifts in spectra of alkali neutrals or singly-ionized alkaline-earths are used to measure the strong electric (10{sup 9} V/m) an magnetic ({approx} 6 T) fields in the diode gap. Large Stark shifts within 0.5 mm of the anode indicate the LiF emits with a finite field threshold rather than with Child-Langmuir-type emission, and the small slope in the electric field indicates an unexpected build-up of electrons near the anode. In the diode gap, the authors aim to unfold fields to quantify the time-dependent ion and electron space-charge distributions that determine the ion beam properties. Observed electric field non-uniformities give local beam deflections that can be comparable to the total beam microdivergence. The authors are implementing active laser absorption and laser-induced fluorescence spectroscopy on low-density Na atoms injected into the diode gap prior to the power pulse. The small Doppler broadening in the Na spectra should allow simultaneous electric and magnetic field mapping with improved spatial resolution. (author). 4 figs., 13 refs.

Fuel-air mixing and distribution in a direct-injection stratified-charge rotary engine

Science.gov (United States)

Abraham, J.; Bracco, F. V.

1989-01-01

A three-dimensional model for flows and combustion in reciprocating and rotary engines is applied to a direct-injection stratified-charge rotary engine to identify the main parameters that control its burning rate. It is concluded that the orientation of the six sprays of the main injector with respect to the air stream is important to enhance vaporization and the production of flammable mixture. In particular, no spray should be in the wake of any other spray. It was predicted that if such a condition is respected, the indicated efficiency would increase by some 6 percent at higher loads and 2 percent at lower loads. The computations led to the design of a new injector tip that has since yielded slightly better efficiency gains than predicted.

Effect of prostaglandin E2 injection on the structural properties of the rat patellar tendon

Directory of Open Access Journals (Sweden)

Ferry Scott T

2012-01-01

Full Text Available Abstract Background Increased tendon production of the inflammatory mediator prostaglandin E2 (PGE2 has been suggested to be a potential etiologic agent in the development of tendinopathy. Repeated injection of PGE2 into tendon has been proposed as a potential animal model for studying treatments for tendinopathy. In contrast, nonsteroidal anti-inflammatory drugs (NSAIDs which inhibit PGE2 production and are commonly prescribed in treating tendinopathy have been shown to impair the healing of tendon after acute injury in animal models. The contradictory literature suggests the need to better define the functional effects of PGE2 on tendon. Our objective was to characterize the effects of PGE2 injection on the biomechanical and biochemical properties of tendon and the activity of the animals. Our hypothesis was that weekly PGE2 injection to the rat patellar tendon would lead to inferior biomechanical properties. Methods Forty rats were divided equally into four groups. Three groups were followed for 4 weeks with the following peritendinous injection procedures: No injection (control, 4 weekly injections of saline (saline, 4 weekly injections of 800 ng PGE2 (PGE2-4 wks. The fourth group received 4 weekly injections of 800 ng PGE2 initially and was followed for a total of 8 weeks. All animals were injected bilaterally. The main outcome measurements included: the structural and material properties of the patellar tendon under tensile loading to failure, tendon collagen content, and weekly animal activity scores. Results The ultimate load of PGE2-4 wks tendons at 4 weeks was significantly greater than control or saline group tendons. The stiffness and elastic modulus of the PGE2 injected tendons at 8 weeks was significantly greater than the control or saline tendons. No differences in animal activity, collagen content, or mean fibril diameter were observed between groups. Conclusions Four weekly peritendinous injections of PGE2 to the rat patellar

Influence of injection temperatures and fiberglass compositions on mechanical properties of polypropylene

Science.gov (United States)

Keey, Tony Tiew Chun; Azuddin, M.

2017-06-01

Injection molding process appears to be one of the most suitable mass and cost efficiency manufacturing processes for polymeric parts nowadays due to its high efficiency of large scale production. When down-scaling the products and components, the limits of conventional injection molding process are reached. These constraints had initiated the development of conventional injection molding process into a new era of micro injection molding technology. In this study, fiberglass reinforced polypropylenes (PP) with various glass fiber percentage materials were used. The study start with fabrication of micro tensile specimens at three different injection temperature, 260°C, 270°C and 280°C for different percentage by weight of fiberglass reinforced PP. Then evaluate the effects of various injection temperatures on the tensile properties of micro tensile specimens. Different percentage by weight of fiberglass reinforced PP were tested as well and it was found that 20% fiberglass reinforced PP possessed the greatest percentage increase of tensile strength with increasing temperatures.

Laboratory Studies of Charging Properties of Dust Grains in Astrophysical/Planetary Environments

Science.gov (United States)

Tankosic, D.; Abbas, M. M.

2012-01-01

Dust grains in various astrophysical environments are generally charged electrostatically by photoelectric emissions with UV/X-ray radiation, as well as by electron/ion impact. Knowledge of physical and optical properties of individual dust grains is required for understanding of the physical and dynamical processes in space environments and the role of dust in formation of stellar and planetary systems. In this paper we focus on charging of individual micron/submicron dust grains by processes that include: (a) UV photoelectric emissions involving incident photon energies higher than the work function of the material and b) electron impact, where low energy electrons are scattered or stick to the dust grains, thereby charging the dust grains negatively, and at sufficiently high energies the incident electrons penetrate the grain leading to excitation and emission of electrons referred to as secondary electron emission (SEE). It is well accepted that the charging properties of individual micron/submicron size dust grains are expected to be substantially different from the bulk materials. However, no viable models for calculation of the charging properties of individual micron size dust grains are available at the present time. Therefore, the photoelectric yields, and secondary electron emission yields of micron-size dust grains have to be obtained by experimental methods. Currently, very limited experimental data are available for charging of individual micron-size dust grains. Our experimental results, obtained on individual, micron-size dust grains levitated in an electrodynamic balance facility (at NASA-MSFC), show that: (1) The measured photoelectric yields are substantially higher than the bulk values given in the literature and indicate a particle size dependence with larger particles having order-of-magnitude higher values than for submicron-size grains; (2) dust charging by low energy electron impact is a complex process. Also, our measurements indicate that

Temperature Dependence and Magnetic Properties of Injection Molding Tool Materials Used in Induction Heating

DEFF Research Database (Denmark)

Guerrier, Patrick; Nielsen, Kaspar Kirstein; Hattel, Jesper Henri

2015-01-01

To analyze the heating phase of an induction heated injection molding tool precisely, the temperature-dependent magnetic properties, B–H curves, and the hysteresis loss are necessary for the molding tool materials. Hence, injection molding tool steels, core materials among other materials have...

Charged Hadron Properties in Background Electric Fields

International Nuclear Information System (INIS)

Detmold, William; Tiburzi, Brian C.; Walker-Loud, Andre

2010-01-01

We report on a lattice calculation demonstrating a novel new method to extract the electric polarizability of charged pseudo-scalar mesons by analyzing two point correlation functions computed in classical background electric fields. A staple component of any electrodynamics or quantum mechanics course is the electric polarizability. Neutral material immersed in a weak external field polarizes, internally setting up an electric dipole moment, aligned so as to minimize the energy. At the atomic level, the electron clouds are distorted creating these microscopic dipole moments. The same process occurs at the hadronic level but the polarization effects are now constrained by the strong force. Polarizabilities of these bound QCD states can be viewed as a distortion of the charged pion cloud of a given hadron. One can use lattice QCD to non-perturbatively compute the quark and gluon interactions in the presence of background electric (or magnetic) fields. For sufficiently weak background fields, the low energy properties of the hadrons can be rigorously computed using effective field theory. With this treatment, a picture of hadrons emerges from chiral dynamics: that of a hadronic core surrounded by a pseudoscalar meson cloud. As some pseudoscalar mesons are charged, polarizabilities of hadrons encode the stiffness of the charged meson cloud (as well as that of the core). The form of pseudoscalar meson polarizabilities is consequently strongly constrained by chiral dynamics. However, beyond the leading order, the results depend upon essentially unknown low-energy constants, which must currently be estimated in a model-dependent fashion. In the case of the charged pion, the experimental measurement of the polarizability has proven difficult, both in the original measurement as well as the most recent published result. Currently, there is a 2-3 sigma discrepancy between the two-loop cPT prediction and the measured charged pion polarizability. New results with higher

Charge Transport in Spiro-OMeTAD Investigated through Space-Charge-Limited Current Measurements

Science.gov (United States)

Röhr, Jason A.; Shi, Xingyuan; Haque, Saif A.; Kirchartz, Thomas; Nelson, Jenny

2018-04-01

Extracting charge-carrier mobilities for organic semiconductors from space-charge-limited conduction measurements is complicated in practice by nonideal factors such as trapping in defects and injection barriers. Here, we show that by allowing the bandlike charge-carrier mobility, trap characteristics, injection barrier heights, and the shunt resistance to vary in a multiple-trapping drift-diffusion model, a numerical fit can be obtained to the entire current density-voltage curve from experimental space-charge-limited current measurements on both symmetric and asymmetric 2 ,2',7 ,7' -tetrakis(N ,N -di-4-methoxyphenylamine)-9 ,9' -spirobifluorene (spiro-OMeTAD) single-carrier devices. This approach yields a bandlike mobility that is more than an order of magnitude higher than the effective mobility obtained using analytical approximations, such as the Mott-Gurney law and the moving-electrode equation. It is also shown that where these analytical approximations require a temperature-dependent effective mobility to achieve fits, the numerical model can yield a temperature-, electric-field-, and charge-carrier-density-independent mobility. Finally, we present an analytical model describing trap-limited current flow through a semiconductor in a symmetric single-carrier device. We compare the obtained charge-carrier mobility and trap characteristics from this analytical model to the results from the numerical model, showing excellent agreement. This work shows the importance of accounting for traps and injection barriers explicitly when analyzing current density-voltage curves from space-charge-limited current measurements.

Alteration of Skin Mechanical Properties in Patients Undergoing Botulinum Toxin Type A Injections of Forehead Rhytides.

Science.gov (United States)

Min, Peiru; Zhang, Zheng; Grassetti, Luca; Perdanasari, Aurelia Trisliana; Torresetti, Matteo; Pu, Zheming; Zhang, Yan; Han, Sheng; Marsili, Riccardo; Zhang, Yi Xin; di Benedetto, Giovanni; Lazzeri, Davide

2016-06-01

Although application of botulinum toxin type A (BTX-A) for the treatment of forehead rhytides has become very popular, the effects of its intramuscular injections on the skin mechanical properties remain unclear. We prospectively investigated the alterations in the mechanical properties of the skin of patients who received intramuscular injections of botulinum toxin A (BTX-A) for forehead rhytides and compared two injection doses. Of the 42 enrolled patients, one randomly assigned half received intramuscular injections of two units (group I), and the other half received four units (group II) of BTX-A in each injection point. The baseline and post-treatment skin mechanical parameters, including gross elasticity (R2), net elasticity (R5), viscoelastic ratio (R6) and biological elasticity (R7), were measured using the Cutometer(®) and compared. Treatment with BTX-A resulted in significant overall alterations in the mechanical properties of skin at the injection sites of both treatment groups during the 16-week period, and no significant differences were observed between groups. Significant decreases in biological elasticity, net elasticity and viscoelasticity properties were observed at 2 weeks follow-up and began to recover at that time. All of the skin mechanical properties recovered to baseline levels by 16 weeks of follow-up in both dosage groups, which indicates that the higher dosage (4 units) did not delay relapse compared to the two-unit dosage. We concluded that intramuscular injections of BTX-A significantly regulated the gross elasticity, net elasticity, functional elasticity and viscoelastic elasticity at the injection point over a radius of 1.5 cm at 2, 4 and 8 weeks follow-up. The alteration in the skin measurements had completely diminished by the 16-week follow-up. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or

Increasing energy efficiency of a gasoline direct injection engine through optimal synchronization of single or double injection strategies

International Nuclear Information System (INIS)

Costa, Michela; Sorge, Ugo; Allocca, Luigi

2012-01-01

Highlights: ► Advantages of split injection in a GDI engine are studied through numerical simulation. ► At high load and speed, rich conditions, split injection does not improve engine performance. ► At moderate load and speed, lean conditions, double injection improves charge stratification. ► Optimal double injection increases work, reduces HC and increases NO. - Abstract: The greatest fuel efficiency advantages of gasoline direct injection (GDI) engines are achieved under the so-called mixed mode boosting, where mixture characteristics are properly adapted to the specific working condition. In particular, in the medium range of load and speed, overall lean mixtures are suitable of being used in the so-called direct injection stratified charge operation. Present paper reports the results of numerical optimization analyses aimed at increasing the energetic efficiency of a GDI engine equipped with a high pressure multi-hole injector under both single and double injection events. In moderate-load moderate-speed lean conditions, the single or double injection synchronization in the working cycle is effected through a procedure that couples a 3D numerical model of the in-cylinder processes with an optimization tool. The choice of both the start of the injection events and the time of spark advance is realized to maximize the engine work. The optimal double injection solution is shown to increase the engine energy efficiency with respect to the case injection is realized in one shot, thus confirming that split injections improve the quality of the charge stratification under lean operation. The effect on the major pollutants is also discussed.

A study of a direct-injection stratified-charge rotary engine for motor vehicle application

Science.gov (United States)

Kagawa, Ryoji; Okazaki, Syunki; Somyo, Nobuhiro; Akagi, Yuji

1993-03-01

A study of a direct-injection stratified-charge system (DISC), as applied to a rotary engine (RE) for motor vehicle usage, was undertaken. The goals of this study were improved fuel consumption and reduced exhaust emissions. These goals were thought feasible due to the high thermal efficiency associated with the DISC-RE. This was the first application of this technology to a motor vehicle engine. Stable ignition and ideal stratification systems were developed by means of numerical calculations, air-fuel mixture measurements, and actual engine tests. The use of DISC resulted in significantly improved fuel consumption and reduced exhaust emissions. The use of an exhaust gas recirculating system was studied and found to be beneficial in NOx reduction.

Transverse acceptance calculation for continuous ion beam injection into the electron beam ion trap charge breeder of the ReA post-accelerator

Energy Technology Data Exchange (ETDEWEB)

Kittimanapun, K., E-mail: kritsadak@slri.or.th [National Superconducting Cyclotron Laboratory (NSCL), Michigan State University (MSU), 640 S. Shaw Lane, East Lansing, Michigan 48824 (United States); Synchrotron Light Research Institute (SLRI), 111 University Avenue, Muang District, Nakhon Ratchasima, 30000 (Thailand); Baumann, T.M.; Lapierre, A.; Schwarz, S. [National Superconducting Cyclotron Laboratory (NSCL), Michigan State University (MSU), 640 S. Shaw Lane, East Lansing, Michigan 48824 (United States); Bollen, G. [National Superconducting Cyclotron Laboratory (NSCL), Michigan State University (MSU), 640 S. Shaw Lane, East Lansing, Michigan 48824 (United States); Facility for Rare Isotope Beams (FRIB), Michigan State University, 640 S. Shaw Lane, East Lansing, Michigan 48824 (United States)

2015-11-11

The ReA post-accelerator at the National Superconducting Cyclotron Laboratory (NSCL) employs an electron beam ion trap (EBIT) as a charge breeder. A Monte-Carlo simulation code was developed to calculate the transverse acceptance phase space of the EBIT for continuously injected ion beams and to determine the capture efficiency in dependence of the transverse beam emittance. For this purpose, the code records the position and time of changes in charge state of injected ions, leading either to capture or loss of ions. To benchmark and validate the code, calculated capture efficiencies were compared with results from a geometrical model and measurements. The results of the code agree with the experimental findings within a few 10%. The code predicts a maximum total capture efficiency of 50% for EBIT parameters readily achievable and an efficiency of up to 80% for an electron beam current density of 1900 A/cm{sup 2}.

Electro-optical and charge injection investigations of the donor-π-acceptor triphenylamine, oligocene–thiophene–pyrimidine and cyanoacetic acid based multifunctional dyes

Directory of Open Access Journals (Sweden)

Ahmad Irfan

2015-10-01

Full Text Available The corner stone of present study is to tune the electro-optical and charge transport properties of donor-bridge-acceptor (D-π-A triphenylamine (TPA derivatives. In the present investigation, an electron deficient moiety (pyrimidine, electron-rich moiety (thiophene and oligocene (benzene, naphthalene, anthracene, tetracene and pentacene have been incorporated as π-spacer between the donor TPA unit and cyanoacetic acid acceptor and anchoring group. The elongation of bridge usually affects the energy levels, i.e., higher the highest occupied molecular orbital (HOMO while lower the lowest unoccupied molecular orbital (LUMO thus reduces the HOMO–LUMO energy gap. The lowered LUMO energy levels of cyano-{2-[6-(4-diphenylamino-phenyl-pyrimidin-4-yl]-tetraceno[2,3-b]thiophen-8-yl}-acetic acid (TPA-PTT4 and cyano-{2-[6-(4-diphenylamino-phenyl-pyrimidin-4-yl]-pentaceno[2,3-b]thiophen-9-yl}-acetic acid (TPA-PPT5 dyes revealed that electron injected from dye to semiconductor surface might be auxiliary stable resulting in impediment of quenching. The broken co-planarity between the π-spacer conceiving LUMO and the TPA moiety would help to impede the recombination process. Moreover, it is expected that TPA derivatives with the tetracenothiophene and pentacenothiophene moieties as π-bridge would show better photovoltaic performance due to lowered LUMO energy level, higher electronic coupling constant, light harvesting efficiency and electron injection values.

The kicker magnet system for TRISTAN Accumulation Ring injection

International Nuclear Information System (INIS)

Sakamoto, Y.; Satoh, K.; Nakayama, H.

1994-12-01

The injection of electron beams to TRISTAN Accumulation Ring (AR) was started in November 1983 and the positron injection started in November 1985. For the injection of electron and positron beams to AR, the unique kicker system was developed. In the kicker power supply the charging to the main capacitor was done with the resonant charge system together with the auxiliary charging unit. The impedance matching circuit was added to the kicker magnet for getting the required current form with least reflecting oscillation. In this paper we report the performance of this kicker system. (author)

Properties of structural steels melted out of high-purity charge

International Nuclear Information System (INIS)

Marchenko, V.N.; Sergeeva, T.K.; Kondakova, N.K.; Morozov, V.P.; Madorskij, L.L.

1993-01-01

A comparative evaluation has been made of impurities, mechanical properties and hydrogen embirittlement parameters for steels type 40Kh and 40KhS produced by electrometallurgical method with the use of direct reduced charge (DR-steels) and melted in an open-hearth furnace. Investigation results have shown that 40Kh and 40KhS Dr-steels have more coarse austenitic grains and experience more complete transformation of martensite into ferritic-pearlitic mixture on tempering. Threshold stresses increase 2.5 times due to purity enhancement at the expense of application of direct reduced charge

Effects of Te inclusions on charge-carrier transport properties in CdZnTe radiation detectors

International Nuclear Information System (INIS)

Gu, Yaxu; Rong, Caicai; Xu, Yadong; Shen, Hao; Zha, Gangqiang; Wang, Ning; Lv, Haoyan; Li, Xinyi; Wei, Dengke; Jie, Wanqi

2015-01-01

Highlights: • This work reveals the behaviors of Te inclusion in affecting charge-carrier transport properties in CdZnTe detectors for the first time and analysis the mechanism therein. • The results show that charge collection efficiencies in Te inclusion degraded regions experience fast ascent under low biases and slow descent at high applied biases, which deviates from the Hecht rule. • This phenomenon is attributed to the competitive influence of two mechanisms under different biases, namely charge carrier trapping due to uniformly distributed point defects and Te inclusion induced transient charge loss. • A modified Hecht equation is further proposed to explain the effects of high-density localized defects, say Te inclusions, on the charge collection efficiency. • We believe that this research has wide appeal to analyze the macroscopic defects and their influence on charge transport properties in semiconductor radiation detectors. - Abstract: The influence of tellurium (Te) inclusions on the charge collection efficiency in cadmium zinc telluride (CdZnTe or CZT) detectors has been investigated using ion beam induced charge (IBIC) technique. Combining the analysis of infrared transmittance image, most of the low charge collection areas in the IBIC images prove the existence of Te inclusions. To further clarify the role of Te inclusions on charge transport properties, bias dependent local IBIC scan was performed on Te inclusion related regions from 20 V to 500 V. The result shows that charge collection efficiencies in Te inclusion degraded regions experience fast ascent under low biases and slow descent at high applied biases, which deviates from Hecht rule. This behavior is attributed to the competitive influence of two mechanisms under different biases, namely charge carrier trapping due to uniformly distributed point defects and Te inclusion induced transient charge loss. A modified Hecht equation is further proposed to explain the effects of high

Effect of Surface Hydration on Antifouling Properties of Mixed Charged Polymers.

Science.gov (United States)

Leng, Chuan; Huang, Hao; Zhang, Kexin; Hung, Hsiang-Chieh; Xu, Yao; Li, Yaoxin; Jiang, Shaoyi; Chen, Zhan

2018-05-07

Interfacial water structure on a polymer surface in water (or surface hydration) is related to the antifouling activity of the polymer. Zwitterionic polymer materials exhibit excellent antifouling activity due to their strong surface hydration. It was proposed to replace zwitterionic polymers using mixed charged polymers because it is much easier to prepare mixed charged polymer samples with much lower costs. In this study, using sum frequency generation (SFG) vibrational spectroscopy, we investigated interfacial water structures on mixed charged polymer surfaces in water, and how such structures change while exposing to salt solutions and protein solutions. The 1:1 mixed charged polymer exhibits excellent antifouling property while other mixed charged polymers with different ratios of the positive/negative charges do not. It was found that on the 1:1 mixed charged polymer surface, SFG water signal is dominated by the contribution of the strongly hydrogen bonded water molecules, indicating strong hydration of the polymer surface. The responses of the 1:1 mixed charged polymer surface to salt solutions are similar to those of zwitterionic polymers. Interestingly, exposure to high concentrations of salt solutions leads to stronger hydration of the 1:1 mixed charged polymer surface after replacing the salt solution with water. Protein molecules do not substantially perturb the interfacial water structure on the 1:1 mixed charged polymer surface and do not adsorb to the surface, showing that this mixed charged polymer is an excellent antifouling material.

Fault injection as a test method for an FPGA in charge of data readout for a large tracking detector

CERN Document Server

Roed, K; Richter, M; Fehlker, D; Helstrup, H; Alme, J; Ullaland, K

2011-01-01

This paper describes how fault injection has been implemented as a test method for an FPGA in an existing hardware configuration setup. As this FPGA is in charge of data readout for a large tracking detector, the reliability of this FPGA is of high importance. Due to the complexity of the readout electronics, irradiation testing is technically difficult at this stage of the system commissioning. The work presented in this paper is therefore motivated by introducing fault injection as an alternative method to characterize failures caused by SEUs. It is a method to study the effect that a configuration upset may have on the operation of the FPGA. The target platform consists of two independent modules for data acquisition and detector control functionality. Fault injection to test the response of the data acquisition module is made possible by implementing the solution as part of the detector control functionality. Correct implementation is validated by a simple shift register design. Our results demonstrate th...

Electronic properties of disordered Weyl semimetals at charge neutrality

Science.gov (United States)

Holder, Tobias; Huang, Chia-Wei; Ostrovsky, Pavel M.

2017-11-01

Weyl semimetals have been intensely studied as a three-dimensional realization of a Dirac-like excitation spectrum where the conduction bands and valence bands touch at isolated Weyl points in momentum space. Like in graphene, this property entails various peculiar electronic properties. However, recent theoretical studies have suggested that resonant scattering from rare regions can give rise to a nonzero density of states even at charge neutrality. Here, we give a detailed account of this effect and demonstrate how the semimetallic nature is suppressed at the lowest scales. To this end, we develop a self-consistent T -matrix approach to investigate the density of states beyond the limit of weak disorder. Our results show a nonvanishing density of states at the Weyl point, which exhibits a nonanalytic dependence on the impurity density. This unusually strong effect of rare regions leads to a revised estimate for the conductivity close to the Weyl point and emphasizes possible deviations from semimetallic behavior in dirty Weyl semimetals at charge neutrality even with very low impurity concentration.

Electrostatic nanopatterning of PMMA by AFM charge writing for directed nano-assembly

International Nuclear Information System (INIS)

Ressier, L; Nader, V Le

2008-01-01

Electrostatic nanopatterning of poly(methylmethacrylate) (PMMA) thin films by atomic force microscopy (AFM) charge writing was investigated using Kelvin force microscopy (KFM). The lateral size of the electrostatic patterns and the amount of injected charges are closely correlated and can be controlled by the height of the voltage pulses applied to the AFM tip and the tip-sample separation during the writing process. Charge retention measurements show that PMMA has excellent charge storage properties in air under relative humidities from 1% to 60% and withstands immersion in ultra-pure water. This study thus reveals that PMMA is a very promising electret to create efficient electrostatic nanopatterns for directed self-assembly of nanoscale objects, including the broad range of colloidal particles or molecules in aqueous solutions

Charge transfer properties of pentacene adsorbed on silver: DFT study

Energy Technology Data Exchange (ETDEWEB)

N, Rekha T.; Rajkumar, Beulah J. M., E-mail: beulah-rajkumar@yahoo.co.in [PG & Research Department of Physics, Lady Doak College, Madurai 625002 (India)

2015-06-24

Charge transfer properties of pentacene adsorbed on silver is investigated using DFT methods. Optimized geometry of pentacene after adsorption on silver indicates distortion in hexagonal structure of the ring close to the silver cluster and deviations in co-planarity of carbon atoms due to the variations in bond angles and dihedral angles. Theoretically simulated absorption spectrum has a symmetric surface plasmon resonance peak around 486nm corresponding to the transfer of charge from HOMO-2 to LUMO. Theoretical SERS confirms the process of adsorption, tilted orientation of pentacene on silver surface and the charge transfers reported. Localization of electron density arising from redistribution of electrostatic potential together with a reduced bandgap of pentacene after adsorption on silver suggests its utility in the design of electro active organic semiconducting devices.

The control mechanism of surface traps on surface charge behavior in alumina-filled epoxy composites

International Nuclear Information System (INIS)

Li, Chuanyang; Hu, Jun; Lin, Chuanjie; He, Jinliang

2016-01-01

To investigate the role surface traps play in the charge injection and transfer behavior of alumina-filled epoxy composites, surface traps with different trap levels are introduced by different surface modification methods which include dielectric barrier discharges plasma, direct fluorination, and Cr 2 O 3 coating. The resulting surface physicochemical characteristics of experimental samples were observed using atomic force microscopy, scanning electron microscopy and fourier transform infrared spectroscopy. The surface potential under dc voltage was detected and the trap level distribution was measured. The results suggest that the surface morphology of the experimental samples differs dramatically after treatment with different surface modification methods. Different surface trap distributions directly determine the charge injection and transfer property along the surface. Shallow traps with trap level of 1.03–1.11 eV and 1.06–1.13 eV introduced by plasma and fluorination modifications are conducive for charge transport along the insulating surface, and the surface potential can be modified, producing a smoother potential curve. The Cr 2 O 3 coating can introduce a large number of deep traps with energy levels ranging from 1.09 to 1.15 eV. These can prevent charge injection through the reversed electric field formed by intensive trapped charges in the Cr 2 O 3 coatings. (paper)

Biomimetic properties of an injectable chitosan/nano-hydroxyapatite/collagen composite

Energy Technology Data Exchange (ETDEWEB)

Huang Zhi [Laboratory of Advanced Materials, Department of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Feng Qingling, E-mail: biomater@mail.tsinghua.edu.cn [Laboratory of Advanced Materials, Department of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Yu Bo; Li Songjian [Department of Orthopedics, Zhujiang Hospital of Southern Medical University, Guangzhou 510282 (China)

2011-04-08

To meet the challenges of designing an injectable scaffold and regenerating bone with complex three-dimensional (3D) structures, a biomimetic and injectable hydrogel scaffold based on nano-hydroxyapatite (HA), collagen (Col) and chitosan (Chi) is synthesized. The chitosan/nano-hydroxyapatite/collagen (Chi/HA/Col) solution rapidly forms a stable gel at body temperature. It shows some features of natural bone both in main composition and microstructure. The Chi/HA/Col system can be expected as a candidate for workable systemic minimally invasive scaffolds with surface properties similar to physiological bone based on scanning electron microscopic (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) results.

Biomimetic properties of an injectable chitosan/nano-hydroxyapatite/collagen composite

International Nuclear Information System (INIS)

Huang Zhi; Feng Qingling; Yu Bo; Li Songjian

2011-01-01

To meet the challenges of designing an injectable scaffold and regenerating bone with complex three-dimensional (3D) structures, a biomimetic and injectable hydrogel scaffold based on nano-hydroxyapatite (HA), collagen (Col) and chitosan (Chi) is synthesized. The chitosan/nano-hydroxyapatite/collagen (Chi/HA/Col) solution rapidly forms a stable gel at body temperature. It shows some features of natural bone both in main composition and microstructure. The Chi/HA/Col system can be expected as a candidate for workable systemic minimally invasive scaffolds with surface properties similar to physiological bone based on scanning electron microscopic (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) results.

Distribution of separated energy and injected charge at normal falling of fast electron beam on target

CERN Document Server

Smolyar, V A; Eremin, V V

2002-01-01

In terms of a kinetic equation diffusion model for a beam of electrons falling on a target along the normal one derived analytical formulae for distributions of separated energy and injected charge. In this case, no empirical adjustable parameters are introduced to the theory. The calculated distributions of separated energy for an electron plate directed source within infinite medium for C, Al, Sn and Pb are in good consistency with the Spencer data derived on the basis of the accurate solution of the Bethe equation being the source one in assumption of a diffusion model, as well

Distribution of separated energy and injected charge at normal falling of fast electron beam on target

International Nuclear Information System (INIS)

Smolyar, V.A.; Eremin, A.V.; Eremin, V.V.

2002-01-01

In terms of a kinetic equation diffusion model for a beam of electrons falling on a target along the normal one derived analytical formulae for distributions of separated energy and injected charge. In this case, no empirical adjustable parameters are introduced to the theory. The calculated distributions of separated energy for an electron plate directed source within infinite medium for C, Al, Sn and Pb are in good consistency with the Spencer data derived on the basis of the accurate solution of the Bethe equation being the source one in assumption of a diffusion model, as well [ru

Tribo-charging properties of waste plastic granules in process of tribo-electrostatic separation

Energy Technology Data Exchange (ETDEWEB)

Li, Jia, E-mail: weee@sjtu.edu.cn; Wu, Guiqing; Xu, Zhenming

2015-01-15

Highlights: • The cyclone charging was more effective and stable than vibrating charging. • The small particle size was better changed than large ones and was more suitable recycled by TES. • The drying pretreatment is good for improving the short-term charging effect. - Abstract: Plastic products can be found everywhere in people’s daily life. With the consistent growth of plastic consumption, more and more plastic waste is generated. Considering the stable chemical and physics characteristics of plastic, regular waste management methods are not suitable for recycling economic strategy of each government, which has become a serious environmental problem. Recycling plastic waste is considered to be the best way to treat it, because it cannot only deduce the waste but also save the energy to produce new virgin plastic. Tribo-electrostatic separation is strongly recommended for plastic separation as it can preserve the original properties of plastic and has little additional pollution. In this study, plastic granules are generated by crushing plastic waste in waste electric and electronic equipment. The tribo-charging properties of plastic waste were studied by vibrating tribo-charging and cyclone tribo-charging. The triboelectric series obtained by vibrating was: (−)-PE–PS–PC–PVC–ABS–PP-(+), while the triboelectric series obtained by cyclone was (−)-PE–PS–PC–PVC–ABS–PP-(+). Further, the cyclone charging was more effective and stable than vibrating charging. The impact factors experiments showed that small particle size was better changed than large ones and were more suitable recycled by tribo-electrostatic separation. High relative humidity was identified as impede charging effect. The results of this study will help defining the operating parameters of subsequent separator.

Tribo-charging properties of waste plastic granules in process of tribo-electrostatic separation

International Nuclear Information System (INIS)

Li, Jia; Wu, Guiqing; Xu, Zhenming

2015-01-01

Highlights: • The cyclone charging was more effective and stable than vibrating charging. • The small particle size was better changed than large ones and was more suitable recycled by TES. • The drying pretreatment is good for improving the short-term charging effect. - Abstract: Plastic products can be found everywhere in people’s daily life. With the consistent growth of plastic consumption, more and more plastic waste is generated. Considering the stable chemical and physics characteristics of plastic, regular waste management methods are not suitable for recycling economic strategy of each government, which has become a serious environmental problem. Recycling plastic waste is considered to be the best way to treat it, because it cannot only deduce the waste but also save the energy to produce new virgin plastic. Tribo-electrostatic separation is strongly recommended for plastic separation as it can preserve the original properties of plastic and has little additional pollution. In this study, plastic granules are generated by crushing plastic waste in waste electric and electronic equipment. The tribo-charging properties of plastic waste were studied by vibrating tribo-charging and cyclone tribo-charging. The triboelectric series obtained by vibrating was: (−)-PE–PS–PC–PVC–ABS–PP-(+), while the triboelectric series obtained by cyclone was (−)-PE–PS–PC–PVC–ABS–PP-(+). Further, the cyclone charging was more effective and stable than vibrating charging. The impact factors experiments showed that small particle size was better changed than large ones and were more suitable recycled by tribo-electrostatic separation. High relative humidity was identified as impede charging effect. The results of this study will help defining the operating parameters of subsequent separator

Synthesis and charge storage properties of double-layered NiSi nanocrystals

International Nuclear Information System (INIS)

Yoon, Jong-Hwan

2010-01-01

Based on bidirectional diffusion of Ni atoms, double-layered nickel silicide (NiSi) nanocrystals (NCs) for multilevel charge storage were fabricated, and their charge storage properties were examined. The double layer was produced by long-term thermal annealing (for 4 h at 900 o C) of a sandwich structure comprised of a thin Ni film of 0.3 nm sandwiched between two silicon-rich oxide (SiO 1.36 ) layers. Transmission electron microscopic image clearly exhibits a distinct NiSi nanocrystal double layer with a gap of about 7 nm between the mean positions of particle distribution in each NC layer. Capacitance-voltage measurements on the metal/oxide/semiconductor (MOS) capacitors with the double-layered NiSi nanocrystals are shown to have the apparent two plateaus of charge storage, the large memory window of about 9 V and the improved charge retention stability.

Charge exchange of hydrogen atoms with multiply charged ions in a hot plasma

International Nuclear Information System (INIS)

Abramov, V.A.; Baryshnikov, F.F.; Lisitsa, V.S.

1980-08-01

The symmetry properties of the hydrogen atom are used to calculate the charge exchange cross-sections sigma of hydrogen with the nuclei of multiply charged ions, allowance being made for the degeneration of final states. If the transitions between these states produced by rotation of the internuclear axis are taken into account, there is a qualitative change in the dependence of sigma on v for low values of v (a gradual decrease in the cross-section instead of the exponential one in the Landau-Zener model) and also a considerable increase in the peak cross-section. The cross-sections are calculated for a wide range of velocities and charge values Z. It is shown that the cross-section may be approximated to within approximately 9 /v).10 -15 cm 2 for Z>=18 (v in cm/s). A detailed comparison with the calculations of various authors is performed. The distribution of final states over orbital angular momenta is found. A calculation is made of variation in the spectral line intensities of the ion O +7 with injection of a neutral hydrogen beam in conditions similar to the experimental conditions on the ORMAK facility. (author)

Multiturn Injection into Accumulators for Heavy Ion Inertial Fusion

CERN Document Server

Prior, C R

1996-01-01

The injection of heavy ions into high current rings is complicated because it is impossible to use charge exchange in material foils to produce the singly charged heavy ions needed to keep space charge manageable on the one hand, and because losses need to be rigorously restricted to < 1 % on the other. With these constraints, the number of turns that may be injected by conventional multiturn injection is limited. This paper describes how the number may be increased by a two-dimensional technique of painting Lissajous-like patterns in x-y space, using an inclined or a corner septum. Simulation examples are presented showing the nature of the beam created in the accumulator and the likely effects of space charge forces.

Negative hydrogen ion injection into the Zero Gradient Synchrotron

International Nuclear Information System (INIS)

Potts, C.W.

1977-01-01

In October 1976 the Zero Gradient Synchrotron (ZGS) became the first high energy proton synchrotron to use charge exchange injection in routine operations. Conversion to H - injection has been very successful, yielding record high beam intensities within the first month of use and normal (>90 percent) operating efficiencies within the second month. A brief discussion is given of the history of H - at the ZGS, the hardware uniquely associated with charge exchange injection, and the operational experience gained during the first two months of H - injection

Effect of Injection Molding Melt Temperatures on PLGA Craniofacial Plate Properties during In Vitro Degradation

Directory of Open Access Journals (Sweden)

Liliane Pimenta de Melo

2017-01-01

Full Text Available The purpose of this article is to present mechanical and physicochemical properties during in vitro degradation of PLGA material as craniofacial plates based on different values of injection molded temperatures. Injection molded plates were submitted to in vitro degradation in a thermostat bath at 37 ± 1°C by 16 weeks. The material was removed after 15, 30, 60, and 120 days; then bending stiffness, crystallinity, molecular weights, and viscoelasticity were studied. A significant decrease of molecular weight and mechanical properties over time and a difference in FT-IR after 60 days showed faster degradation of the material in the geometry studied. DSC analysis confirmed that the crystallization occurred, especially in higher melt temperature condition. DMA analysis suggests a greater contribution of the viscous component of higher temperature than lower temperature in thermomechanical behavior. The results suggest that physical-mechanical properties of PLGA plates among degradation differ per injection molding temperatures.

Improved workability of injectable calcium sulfate bone cement by regulation of self-setting properties

Energy Technology Data Exchange (ETDEWEB)

Chen, Zonggang, E-mail: chenzg@sdu.edu.cn [National Glycoengineering Research Center, Shandong University, Jinan 250100 (China); Department of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Liu, Huanye [Department of Orthodontics, School of Stomatology, China Medical University, Shenyang 110001 (China); Liu, Xi [Department of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Lian, Xiaojie [College of Mechanics, Taiyuan University of Technology, Taiyuan 030024 (China); Guo, Zhongwu [National Glycoengineering Research Center, Shandong University, Jinan 250100 (China); Jiang, Hong-Jiang [Wendeng Hospital of Traditional Chinese Orthopedics and Traumatology, Shandong 264400 (China); Cui, Fu-Zhai, E-mail: cuifz@mail.tsinghua.edu.cn [Department of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China)

2013-04-01

Calcium sulfate hemihydrate (CSH) powder as an injectable bone cement was prepared by hydrothermal synthesis of calcium sulfate dihydrate (CSD). The prepared materials showed X-ray diffraction peaks corresponding to the CSH structure without any secondary phases, implying complete conversion from CSD phase to CSH phase. Thermogravimetric (TG) analyses showed the crystal water content of CSH was about 6.0% (wt.), which is near to the theoretic crystal water value of CSH. From scanning electron microscopy (SEM) micrographs, sheet crystal structure of CSD was observed to transform into rod-like crystal structure of CSH. Most interesting and important of all, CSD as setting accelerator was also introduced into CSH powder to regulate self-setting properties of injectable CSH paste, and thus the self-setting time of CSH paste can be regulated from near 30 min to less than 5 min by adding various amounts of setting accelerator. Because CSD is not only the reactant of preparing CSH but also the final solidified product of CSH, the setting accelerator has no significant effect on the other properties of materials, such as mechanical properties. In vitro biocompatibility and in vivo histology studies have demonstrated that the materials have good biocompatibility and good efficacy in bone regeneration. All these will further improve the workability of CSH in clinic applications. Highlights: ► Calcium sulfate hemihydrate (CSH) can be an injectable bone cement. ► CSH was produced by hydrothermal synthesis of calcium sulfate dihydrate (CSD). ► CSD was introduced into CSH powder to regulate self-setting properties of CSH. ► Setting accelerator has no significant effect on the other properties of materials. ► Injectable CSH has good biocompatibility and good efficacy in bone regeneration.

Improved workability of injectable calcium sulfate bone cement by regulation of self-setting properties

International Nuclear Information System (INIS)

Chen, Zonggang; Liu, Huanye; Liu, Xi; Lian, Xiaojie; Guo, Zhongwu; Jiang, Hong-Jiang; Cui, Fu-Zhai

2013-01-01

Calcium sulfate hemihydrate (CSH) powder as an injectable bone cement was prepared by hydrothermal synthesis of calcium sulfate dihydrate (CSD). The prepared materials showed X-ray diffraction peaks corresponding to the CSH structure without any secondary phases, implying complete conversion from CSD phase to CSH phase. Thermogravimetric (TG) analyses showed the crystal water content of CSH was about 6.0% (wt.), which is near to the theoretic crystal water value of CSH. From scanning electron microscopy (SEM) micrographs, sheet crystal structure of CSD was observed to transform into rod-like crystal structure of CSH. Most interesting and important of all, CSD as setting accelerator was also introduced into CSH powder to regulate self-setting properties of injectable CSH paste, and thus the self-setting time of CSH paste can be regulated from near 30 min to less than 5 min by adding various amounts of setting accelerator. Because CSD is not only the reactant of preparing CSH but also the final solidified product of CSH, the setting accelerator has no significant effect on the other properties of materials, such as mechanical properties. In vitro biocompatibility and in vivo histology studies have demonstrated that the materials have good biocompatibility and good efficacy in bone regeneration. All these will further improve the workability of CSH in clinic applications. Highlights: ► Calcium sulfate hemihydrate (CSH) can be an injectable bone cement. ► CSH was produced by hydrothermal synthesis of calcium sulfate dihydrate (CSD). ► CSD was introduced into CSH powder to regulate self-setting properties of CSH. ► Setting accelerator has no significant effect on the other properties of materials. ► Injectable CSH has good biocompatibility and good efficacy in bone regeneration

Physical properties of charged particle beams for use in radiotherapy

International Nuclear Information System (INIS)

Knapp, E.A.

1975-01-01

The physical properties of the possible charged particle beams used for cancer radiotherapy are reviewed. Each property is discussed for all interesting particles (π, p, α, Ne ion) and the differences are emphasized. This is followed by a short discussion of the several beam delivery systems used in particle therapy today, emphasizing the differences in the problems for the several different radiations, particularly the differences between the accelerated particle beams and those of a secondary nature. Dose calculation techniques are described

Computational investigation of the effects of perfluorination on the charge-transport properties of polyaromatic hydrocarbons

International Nuclear Information System (INIS)

Cardia, R.; Malloci, G.; Bosin, A.; Serra, G.; Cappellini, G.

2016-01-01

We present a systematic computational study of the effects of perfluorination on the charge-transport properties of three homologous classes of polyaromatic hydrocarbons of interest for molecular electronics: acenes, pyrenes, and circumacenes. By means of Density Functional Theory calculations we first obtained the key molecular properties for transport of both holes and electrons. We then used these parameters in the framework of Marcus theory to compare charge-transfer rates in the high temperatures regime for both unsubstituted and perfluorinated molecules. We additionally estimated the relative charge-mobility of each unsubstituted (perfluorinated) molecule with respect to unsubstituted (perfluorinated) pentacene. We found in all cases that perfluorination reduces the charge-transfer rate in absolute terms. This is largely due to the higher values of the molecular reorganization energies predicted for perfluorinated compounds. Interestingly, however, the charge-transfer rates for both holes and electrons of perfluorinated species are remarkably similar, especially for the larger species. In addition, in the case of the larger circumacenes the charge-mobility values relative to pentacene values are found to increase upon perfluorination.

Computational investigation of the effects of perfluorination on the charge-transport properties of polyaromatic hydrocarbons

Energy Technology Data Exchange (ETDEWEB)

Cardia, R. [Università degli studi di Cagliari, Dipartimento di Fisica, Cittadella Universitaria, I-09042 Monserrato (Cagliari) (Italy); Istituto Officina dei Materiali (CNR – IOM), UOS di Cagliari, Cittadella Universitaria, I-09042 Monserrato, Cagliari (Italy); Malloci, G., E-mail: giuliano.malloci@dsf.unica.it [Università degli studi di Cagliari, Dipartimento di Fisica, Cittadella Universitaria, I-09042 Monserrato (Cagliari) (Italy); Bosin, A.; Serra, G. [Università degli studi di Cagliari, Dipartimento di Fisica, Cittadella Universitaria, I-09042 Monserrato (Cagliari) (Italy); Cappellini, G., E-mail: giancarlo.cappellini@dsf.unica.it [Università degli studi di Cagliari, Dipartimento di Fisica, Cittadella Universitaria, I-09042 Monserrato (Cagliari) (Italy); Istituto Officina dei Materiali (CNR – IOM), UOS di Cagliari, Cittadella Universitaria, I-09042 Monserrato, Cagliari (Italy)

2016-10-20

We present a systematic computational study of the effects of perfluorination on the charge-transport properties of three homologous classes of polyaromatic hydrocarbons of interest for molecular electronics: acenes, pyrenes, and circumacenes. By means of Density Functional Theory calculations we first obtained the key molecular properties for transport of both holes and electrons. We then used these parameters in the framework of Marcus theory to compare charge-transfer rates in the high temperatures regime for both unsubstituted and perfluorinated molecules. We additionally estimated the relative charge-mobility of each unsubstituted (perfluorinated) molecule with respect to unsubstituted (perfluorinated) pentacene. We found in all cases that perfluorination reduces the charge-transfer rate in absolute terms. This is largely due to the higher values of the molecular reorganization energies predicted for perfluorinated compounds. Interestingly, however, the charge-transfer rates for both holes and electrons of perfluorinated species are remarkably similar, especially for the larger species. In addition, in the case of the larger circumacenes the charge-mobility values relative to pentacene values are found to increase upon perfluorination.

Electronic properties of mesoscopic graphene structures: Charge confinement and control of spin and charge transport

Energy Technology Data Exchange (ETDEWEB)

Rozhkov, A.V., E-mail: arozhkov@gmail.co [Advanced Science Institute, RIKEN, Wako-shi, Saitama, 351-0198 (Japan); Institute for Theoretical and Applied Electrodynamics, Russian Academy of Sciences, 125412, Moscow (Russian Federation); Giavaras, G. [Advanced Science Institute, RIKEN, Wako-shi, Saitama, 351-0198 (Japan); Bliokh, Yury P. [Advanced Science Institute, RIKEN, Wako-shi, Saitama, 351-0198 (Japan); Department of Physics, Technion-Israel Institute of Technology, Haifa 32000 (Israel); Freilikher, Valentin [Advanced Science Institute, RIKEN, Wako-shi, Saitama, 351-0198 (Japan); Department of Physics, Bar-Ilan University, Ramat-Gan 52900 (Israel); Nori, Franco [Advanced Science Institute, RIKEN, Wako-shi, Saitama, 351-0198 (Japan); Department of Physics, University of Michigan, Ann Arbor, MI 48109-1040 (United States)

2011-06-15

This brief review discusses electronic properties of mesoscopic graphene-based structures. These allow controlling the confinement and transport of charge and spin; thus, they are of interest not only for fundamental research, but also for applications. The graphene-related topics covered here are: edges, nanoribbons, quantum dots, pn-junctions, pnp-structures, and quantum barriers and waveguides. This review is partly intended as a short introduction to graphene mesoscopics.

Effect of fuel injection parameters on combustion stability and emissions of a mineral diesel fueled partially premixed charge compression ignition (PCCI) engine

International Nuclear Information System (INIS)

Jain, Ayush; Singh, Akhilendra Pratap; Agarwal, Avinash Kumar

2017-01-01

Highlights: • NOx and PM emissions were lowest at 700 bar fuel injection pressure (FIP). • PCCI showed lower knocking than compression ignition combustion mode. • Increasing FIP reduced emissions of nitrogen oxides and smoke opacity in PCCI mode. • Increasing FIP reduced nucleation mode particle concentration. • Increasing FIP with advanced main injection timings improved PCCI combustion. - Abstract: This experimental study focuses on developing new combustion concept for compression ignition (CI) engines by achieving partially homogeneous charge, leading to low temperature combustion (LTC). Partially premixed charge compression ignition (PCCI) combustion is a single-stage phenomenon, with combustion shifting towards increasingly premixed combustion phase, resulting in lower in-cylinder temperatures. PCCI leads to relatively lower emissions of oxides of nitrogen (NOx) and particulate matter (PM) simultaneously. To investigate combustion, performance and emission characteristics of the PCCI engine, experiments were performed in a mineral diesel fueled single cylinder research engine, which was equipped with flexible fuel injection equipment (FIE). Effects of fuel injection pressure (FIP) were investigated by changing the FIP from 400 bar to 1000 bar. Experiments were carried out by varying start of main injection (SoMI) timings (from 12° to 24° before top dead center (bTDC)), when using single pilot injection. This experimental study included detailed investigations of particulate characteristics such as particulate number-size distribution using engine exhaust particle sizer (EEPS), particulate bound trace metal analysis using inductively coupled plasma-optical emission spectrometer (ICP-OES), and soot morphology using transmission electron microscopy (TEM). PCCI combustion improved with increasing FIP (up to 700 bar) due to superior fuel atomization however further increasing FIP deteriorated PCCI combustion and engine performance due to intense

Charge Carrier Transport Properties of Vacuum Evaporated Anthrylvinylbenzene Thin Films

Directory of Open Access Journals (Sweden)

Haikel HRICHI

2014-05-01

Full Text Available The charge carrier conduction processes and dielectric properties of two new materials based on anthracene core structure, 1-(9 anthrylvinyl-4-benzyloxybenzene (AVB and 1,4- bis(9-anthrylvinylbenzene (AV2B diodes have been investigated using dc current density–voltage (J–V and AC impedance spectroscopy (100 Hz–10 MHz. The DC electrical properties of ITO/anthracene derivative /Al device showing an ohmic behavior at low voltages and switches to space charge limited current (SCLC conduction with exponential trap distribution at higher voltages. The best performance device was achieved from ITO/AVB/Al structure showing the high charge carrier mobility which has also been evaluated from SCLC as 6.55´10-6 cm/Vs. According to the impedance spectroscopy results the structures were modeled by equivalent circuit designed as a parallel resistor Rp and capacitor Cp network in series with resistor Rs. The evolution of the electrical parameters with frequency and bias voltage of these anthracene-based systems has been discussed. The conductivity s(w evolution with frequency and bias voltage was studied for ITO/anthracene derivatives/Al devices. The dc conductivity sdc for these devices has been determined. The ac conductivity sac showed a variation in angular frequency as A.ws with a critical exponent s< 1 suggesting a hopping conduction mechanism at high frequency.

Universal Disorder in Organic Semiconductors Due to Fluctuations in Space Charge

Science.gov (United States)

Wu, Tzu-Cheng

This thesis concerns the study of charge transport in organic semiconductors. These materials are widely used as thin-film photoconductors in copiers and laser printers, and for their electroluminescent properties in organic light-emitting diodes. Much contemporary research is directed towards improving the efficiency of organic photovoltaic devices, which is limited to a large extent by the spatial and energetic disorder that hinders the charge mobility. One contribution to energetic disorder arises from the strong Coulomb interactions between injected charges with one another, but to date this has been largely ignored. We present a mean-field model for the effect of mutual interactions between injected charges hopping from site to site in an organic semiconductor. Our starting point is a modified Fröhlich Hamiltonian in which the charge is linearly coupled to the amplitudes of a wide band of dispersionless plasma modes having a Lorentzian distribution of frequencies. We show that in most applications of interest the hopping rates are fast enough while the plasma frequencies are low enough that random thermal fluctuations in the plasma density give rise to an energetically disordered landscape that is effectively stationary for many thousands of hops. Moreover, the distribution of site energies is Gaussian, and the energy-energy correlation function decays inversely with distance; as such, it can be argued that this disorder contributes to the Poole-Frenkel field dependence seen in a wide variety of experiments. Remarkably, the energetic disorder is universal; although it is caused by the fluctuations in the charge density, it is independent of the charge concentration.

Evaluation of Heating and Shearing on the Viscoelastic Properties of Calcium Hydroxyapatite Used in Injection Laryngoplasty.

Science.gov (United States)

Mahboubi, Hossein; Mohraz, Ali; Verma, Sunil P

2016-03-01

To compare the viscoelastic properties of calcium hydroxyapatite (CaHA) to carboxymethylcellulose (CMC) injectables used for injection laryngoplasty and determine if they are affected by heating and shearing. Experimental. University laboratory. Vocal fold injection laryngoplasty with CaHA is oftentimes challenging due to the amount of pressure necessary to push the injectate through a needle. Anecdotal techniques, such as heating the product, have been suggested to facilitate injection. The viscoelastic properties of CaHA and CMC were measured with a rheometer. The effects of heating and shearing on sample viscoelasticity were recorded. CaHA was 9.5 times more viscous than CMC (43,100 vs 4540 Pa·s). Heating temporarily decreased the viscosity of CaHA by 32%. However, it also caused the viscosity to subsequently increase after time. Shearing of CaHA reduced its viscosity by 26%. Heating and shearing together temporarily reduced the viscosity of CaHA by 52%. A combination of heating and shearing had a more profound effect than heating or shearing alone on the viscosity of CaHA, potentially making it easier to inject temporarily. Long-term and in vivo studies are required to further analyze the effect of heating and shearing on CaHA injectables. © American Academy of Otolaryngology—Head and Neck Surgery Foundation 2016.

Phase space properties of charged fields in theories of local observables

International Nuclear Information System (INIS)

Buchholz, D.; D'Antoni, C.

1994-10-01

Within the setting of algebraic quantum field theory a relation between phase-space properties of observables and charged fields is established. These properties are expressed in terms of compactness and nuclarity conditions which are the basis for the characterization of theories with physically reasonable causal and thermal features. Relevant concepts and results of phase space analysis in algebraic qunatum field theory are reviewed and the underlying ideas are outlined. (orig.)

Performance and efficiency evaluation and heat release study of a direct-injection stratified-charge rotary engine

Science.gov (United States)

Nguyen, H. L.; Addy, H. E.; Bond, T. H.; Lee, C. M.; Chun, K. S.

1987-01-01

A computer simulation which models engine performance of the Direct Injection Stratified Charge (DISC) rotary engines was used to study the effect of variations in engine design and operating parameters on engine performance and efficiency of an Outboard Marine Corporation (OMC) experimental rotary combustion engine. Engine pressure data were used in a heat release analysis to study the effects of heat transfer, leakage, and crevice flows. Predicted engine data were compared with experimental test data over a range of engine speeds and loads. An examination of methods to improve the performance of the rotary engine using advanced heat engine concepts such as faster combustion, reduced leakage, and turbocharging is also presented.

Tribo-charging properties of waste plastic granules in process of tribo-electrostatic separation.

Science.gov (United States)

Li, Jia; Wu, Guiqing; Xu, Zhenming

2015-01-01

Plastic products can be found everywhere in people's daily life. With the consistent growth of plastic consumption, more and more plastic waste is generated. Considering the stable chemical and physics characteristics of plastic, regular waste management methods are not suitable for recycling economic strategy of each government, which has become a serious environmental problem. Recycling plastic waste is considered to be the best way to treat it, because it cannot only deduce the waste but also save the energy to produce new virgin plastic. Tribo-electrostatic separation is strongly recommended for plastic separation as it can preserve the original properties of plastic and has little additional pollution. In this study, plastic granules are generated by crushing plastic waste in waste electric and electronic equipment. The tribo-charging properties of plastic waste were studied by vibrating tribo-charging and cyclone tribo-charging. The triboelectric series obtained by vibrating was: (-)-PE-PS-PC-PVC-ABS-PP-(+), while the triboelectric series obtained by cyclone was (-)-PE-PS-PC-PVC-ABS-PP-(+). Further, the cyclone charging was more effective and stable than vibrating charging. The impact factors experiments showed that small particle size was better changed than large ones and were more suitable recycled by tribo-electrostatic separation. High relative humidity was identified as impede charging effect. The results of this study will help defining the operating parameters of subsequent separator. Copyright © 2014 Elsevier Ltd. All rights reserved.

Charge transport properties of a twisted DNA molecule: A renormalization approach

Energy Technology Data Exchange (ETDEWEB)

Almeida, M.L. de; Ourique, G.S.; Fulco, U.L. [Departamento de Biofísica e Farmacologia, Universidade Federal do Rio Grande do Norte, 59072-970 Natal-RN (Brazil); Albuquerque, E.L., E-mail: eudenilson@gmail.com [Departamento de Biofísica e Farmacologia, Universidade Federal do Rio Grande do Norte, 59072-970 Natal-RN (Brazil); Moura, F.A.B.F. de; Lyra, M.L. [Instituto de Física, Universidade Federal de Alagoas, 57072-900 Maceió-AL (Brazil)

2016-10-20

In this work we study the charge transport properties of a nanodevice consisting of a finite segment of the DNA molecule sandwiched between two metallic electrodes. Our model takes into account a nearest-neighbor tight-binding Hamiltonian considering the nucleobases twist motion, whose solutions make use of a two-steps renormalization process to simplify the algebra, which can be otherwise quite involved. The resulting variations of the charge transport efficiency are analyzed by numerically computing the main features of the electron transmittance spectra as well as their I × V characteristic curves.

Die-cast of a hypo-eutectic AL-SI alloy: influence of injection temperature on microstructure and mechanical properties

International Nuclear Information System (INIS)

Santos, Silvano Leal dos; Santos, Sydney Ferreira

2014-01-01

Die-casting is widely used for manufacturing light alloy components for automotive industry. Among others, hypo-eutectic Al-Si alloys are currently processed by die-casting. To obtain high quality die-cast components, a better understanding on the correlations between processing parameters, microstructures, and mechanical properties are of utmost importance. In this study, we investigate the effect of injection temperature of liquid metal on the microstructure and mechanical properties of Al-Si alloy EN AC 46000 (DIN designation). The injection temperatures were 579, 589, 643, and 709 deg C. As-cast components had their microstructures analyzed by X-ray diffraction, optical and scanning electron microscopy, and X-ray energy dispersive spectroscopy. The mechanical properties were examined by micro-hardness and tensile tests. It was observed that the ultimate tensile strength slightly increased with the increase of injection temperature. The same trend was observed for micro-hardness. The amount of porosity in the samples varies in a small amount for different injection temperatures. On the other hand, the microstructure of the alloys seems more refined for higher temperatures of injection. This refinement in microstructure might play a major role on the mechanical properties of the Al-Si die-cast alloy. (author)

Study of static properties of magnetron-type space charges; Etude des proprietes statiques des charges d'espace du type magnetron

Energy Technology Data Exchange (ETDEWEB)

Delcroix, Jean-Loup

1953-05-30

This research thesis reports an in-depth analysis of physical properties of static regimes to address the issue of space charges. This theoretical study of the Hull magnetron is followed by the description of experiments on the Hull magnetron which highlight transitions between the different regimes. Then, another theoretical approach aims at generalising the magnetron theory, based on other types of magnetron theory (general equations of magnetron-type space charges, inverted Hull magnetron theory, circular field magnetron theory)

Charging effects of PET under electron beam irradiation in a SEM

International Nuclear Information System (INIS)

Jbara, O; Rondot, S; Hadjadj, A; Patat, J M; Fakhfakh, S; Belhaj, M

2008-01-01

This paper deals with charge trapping and charge transport of polyethylene terephthalate (PET) polymer subjected to electron irradiation in a scanning electron microscope (SEM). Measurement of displacement current and leakage current using an arrangement adapted to the SEM allows the amount of trapped charge during and after electron irradiation to be determined and the charge mechanisms regulation to be studied. These mechanisms involve several parameters related to the electronic injection, the characteristics of insulator and the effects of the trapped charge itself. The dynamic trapping properties of PET samples are investigated and the time constants of charging are evaluated for various conditions of irradiation. The determination of the trapping cross section for electrons is possible by using the trapping rate at the onset of irradiation. Many physical processes are involved in the charging and discharging mechanisms; among them surface conduction is outlined. Through the control of irradiation conditions, various types of surface discharging (flashover phenomenon) behaviour are also observed. The strength of the electric field initiating surface discharge is estimated.

Influence of gas injection on viscous and viscoelastic properties of Xanthan gum.

Science.gov (United States)

Bobade, Veena; Cheetham, Madalyn; Hashim, Jamal; Eshtiaghi, Nicky

2018-05-01

Xanthan gum is widely used as a model fluid for sludge to mimic the rheological behaviour under various conditions including impact of gas injection in sludge. However, there is no study to show the influence of gas injection on rheological properties of xanthan gum specifically at the concentrations at which it is used as a model fluid for sludge with solids concentration above 2%. In this paper, the rheological properties of aqueous xanthan gum solutions at different concentrations were measured over a range of gas injection flow rates. The effect of gas injection on both the flow and viscoelastic behaviour of Xanthan gum (using two different methods - a creep test and a time sweep test) was evaluated. The viscosity curve of different solid concentrations of digested sludge and waste activated sludge were compared with different solid concentrations of Xanthan gum and the results showed that Xanthan gum can mimic the flow behaviour of sludge in flow regime. The results in linear viscoelastic regime showed that increasing gas flow rate increases storage modulus (G'), indicating an increase in the intermolecular associations within the material structure leading to an increase in material strength and solid behaviour. Similarly, in creep test an increase in the gas flow rate decreased strain%, signifying that the material has become more resistant to flow. Both observed behaviour is opposite to what occurs in sludge under similar conditions. The results of both the creep test and the time sweep test indicated that choosing Xanthan gum aqueous solution as a transparent model fluid for sludge in viscoelastic regime under similar conditions involving gas injection in a concentration range studied is not feasible. However Xanthan gum can be used as a model material for sludge in flow regime; because it shows a similar behaviour to sludge. Copyright © 2018 Elsevier Ltd. All rights reserved.

Tetracene-based organic light-emitting transistors: optoelectronic properties and electron injection mechanism

NARCIS (Netherlands)

Santato, C.; Capelli, R.; Loi, M.A.; Murgia, M.; Cicoira, F.; Roy, Arunesh; Stallinga, P; Zamboni, R.; Rost, C.; Karg, S.F.; Muccini, M.

2004-01-01

Optoelectronic properties of light-emitting field-effect transistors (LETs) fabricated on bottom-contact transistor structures using a tetracene film as charge-transport and light-emitting material are investigated. Electroluminescence generation and transistor current are correlated, and the bias

Efficient Spin Injection into Semiconductor

International Nuclear Information System (INIS)

Nahid, M.A.I.

2010-06-01

Spintronic research has made tremendous progress nowadays for making future devices obtain extra advantages of low power, and faster and higher scalability compared to present electronic devices. A spintronic device is based on the transport of an electron's spin instead of charge. Efficient spin injection is one of the very important requirements for future spintronic devices. However, the effective spin injection is an exceedingly difficult task. In this paper, the importance of spin injection, basics of spin current and the essential requirements of spin injection are illustrated. The experimental technique of electrical spin injection into semiconductor is also discussed based on the experimental experience. The electrical spin injection can easily be implemented for spin injection into any semiconductor. (author)

Factor Structure and Psychometric Properties of the Injection Phobia Scale-Anxiety

Science.gov (United States)

Olatunji, Bunmi O.; Sawchuk, Craig N.; Moretz, Melanie W.; David, Bieke; Armstrong, Thomas; Ciesielski, Bethany G.

2010-01-01

The present investigation examined the factor structure and psychometric properties of the Injection Phobia Scale-Anxiety (IPS-Anx). Principal components analysis of IPS-Anx items in Study 1 (n = 498) revealed a 2-factor structure consisting of Distal Fear and Contact Fear. However, CFA results in Study 2 (n = 567) suggest that a 1-factor…

Organic integrated circuits for information storage based on ambipolar polymers and charge injection engineering

Science.gov (United States)

Dell'Erba, Giorgio; Luzio, Alessandro; Natali, Dario; Kim, Juhwan; Khim, Dongyoon; Kim, Dong-Yu; Noh, Yong-Young; Caironi, Mario

2014-04-01

Ambipolar semiconducting polymers, characterized by both high electron (μe) and hole (μh) mobility, offer the advantage of realizing complex complementary electronic circuits with a single semiconducting layer, deposited by simple coating techniques. However, to achieve complementarity, one of the two conduction paths in transistors has to be suppressed, resulting in unipolar devices. Here, we adopt charge injection engineering through a specific interlayer in order to tune injection into frontier energy orbitals of a high mobility donor-acceptor co-polymer. Starting from field-effect transistors with Au contacts, showing a p-type unbalanced behaviour with μh = 0.29 cm2/V s and μe = 0.001 cm2/V s, through the insertion of a caesium salt interlayer with optimized thickness, we obtain an n-type unbalanced transistor with μe = 0.12 cm2/V s and μh = 8 × 10-4 cm2/V s. We applied this result to the development of the basic pass-transistor logic building blocks such as inverters, with high gain and good noise margin, and transmission-gates. In addition, we developed and characterized information storage circuits like D-Latches and D-Flip-Flops consisting of 16 transistors, demonstrating both their static and dynamic performances and thus the suitability of this technology for more complex circuits such as display addressing logic.

The effects of intratendinous and retrocalcaneal intrabursal injections of corticosteroid on the biomechanical properties of rabbit Achilles tendons.

Science.gov (United States)

Hugate, Ronald; Pennypacker, Jason; Saunders, Marnie; Juliano, Paul

2004-04-01

The use of corticosteroid injections in the treatment of retrocalcaneal bursitis is controversial. We assessed the effects of corticosteroid injections, both within the tendon substance and into the retrocalcaneal bursa, on the biomechanical properties of rabbit Achilles tendons. The systemic effects of bilateral corticosteroid injections were also studied. The rabbits were divided into three treatment groups. The rabbits in Group I received injections of corticosteroid into the Achilles tendon on the left side and injections of normal saline solution into the Achilles tendon on the right, those in Group II received injections of corticosteroid into the retrocalcaneal bursa on the left side and injections of saline solution into the Achilles tendon on the right, and those in Group III received injections of corticosteroid into the Achilles tendon on the left side and injections of corticosteroid into the retrocalcaneal bursa on the right. These injections were given weekly for three weeks. At four weeks after the final injection, the tendons were harvested and were tested biomechanically to determine failure load, midsubstance strain and total strain, modulus of elasticity, failure stress, and total energy absorbed. The site of failure was also documented. The groups were compared according to the location of the injections, the type of injection (steroid or saline solution), and the total systemic load of steroid. Specimens from limbs that had received intratendinous injections of corticosteroid showed significantly decreased failure stress compared with those from limbs that had received intratendinous injections of saline solution (p = 0.008). Specimens from limbs that had received intrabursal injections of corticosteroid demonstrated significantly decreased failure stress (p = 0.05), significantly decreased total energy absorbed (p = 0.017), and significantly increased total strain (p = 0.049) compared with specimens from limbs that had received intratendinous

Transport and Fatigue Properties of Ferroelectric Polymer P(VDF-TrFE) For Nonvolatile Memory Applications

KAUST Repository

Hanna, Amir

2012-06-01

Organic ferroelectrics polymers have recently received much interest for use in nonvolatile memory devices. The ferroelectric copolymer poly(vinylidene fluoride- trifluoroethylene) , P(VDF-TrFE), is a promising candidate due to its relatively high remnant polarization, low coercive field, fast switching times, easy processability, and low Curie transition. However, no detailed study of charge injection and current transport properties in P(VDF-TrFE) have been reported in the literature yet. Charge injection and transport are believed to affect various properties of ferroelectric films such as remnant polarization values and polarization fatigue behavior.. Thus, this thesis aims to study charge injection in P(VDF-TrFE) and its transport properties as a function of electrode material. Injection was studied for Al, Ag, Au and Pt electrodes. Higher work function metals such as Pt have shown less leakage current compared to lower work function metals such as Al for more than an order of magnitude. That implied n-type conduction behavior for P(VDF-TrFE), as well as electrons being the dominant injected carrier type. Charge transport was also studied as a function of temperature, and two major transport regimes were identified: 1) Thermionic emission over a Schottky barrier for low fields (E < 25 MV/m). 2) Space-Charge-Limited regime at higher fields (25 < E <120 MV/m). We have also studied the optical imprint phenomenon, the polarization fatigue resulting from a combination of broad band optical illumination and DC bias near the switching field. A setup was designed for the experiment, and validated by reproducing the reported effect in polycrystalline Pb(Zr,Ti)O3 , PZT, film. On the other hand, P(VDF-TrFE) film showed no polarization fatigue as a result of optical imprint test, which could be attributed to the large band gap of the material, and the low intensity of the UV portion of the arc lamp white light used for the experiment. Results suggest using high work

Effect of five-membered ring and heteroatom substitution on charge transport properties of perylene discotic derivatives: A theoretical approach

Energy Technology Data Exchange (ETDEWEB)

Navarro, Amparo, E-mail: anavarro@ujaen.es; Fernández-Liencres, M. Paz; Peña-Ruiz, Tomás; Granadino-Roldán, José M.; Fernández-Gómez, Manuel [Departamento de Química Física y Analítica, Universidad de Jaén, Campus Las Lagunillas, E23071 Jaén (Spain); García, Gregorio [Instituto de Energía Solar and Departamento TFB, E.T.S.I. Telecomunicación, Universidad Politécnica de Madrid, Ciudad Universitaria, Madrid 28040 (Spain)

2016-08-07

Density functional theory calculations were carried out to investigate the evolvement of charge transport properties of a set of new discotic systems as a function of ring and heteroatom (B, Si, S, and Se) substitution on the basic structure of perylene. The replacement of six-membered rings by five-membered rings in the reference compound has shown a prominent effect on the electron reorganization energy that decreases ∼0.2 eV from perylene to the new carbon five-membered ring derivative. Heteroatom substitution with boron also revealed to lower the LUMO energy level and increase the electron affinity, therefore lowering the electron injection barrier compared to perylene. Since the rate of the charge transfer between two molecules in columnar discotic systems is strongly dependent on the orientation of the stacked cores, the total energy and transfer integral of a dimer as a disc is rotated with respect to the other along the stacking axis have been predicted. Aimed at obtaining a more realistic approach to the bulk structure, the molecular geometry of clusters made up of five discs was fully optimized, and charge transfer rate and mobilities were estimated for charge transport along a one dimensional pathway. Heteroatom substitution with selenium yields electron transfer integral values ∼0.3 eV with a relative disc orientation of 25°, which is the preferred angle according to the dimer energy profile. All the results indicate that the tetraselenium-substituted derivative, not synthetized so far, could be a promising candidate among those studied in this work for the fabrication of n-type semiconductors based on columnar discotic liquid crystals materials.

Influence of solvent polarization and non-uniform ion size on electrostatic properties between charged surfaces in an electrolyte solution

Science.gov (United States)

Sin, Jun-Sik

2017-12-01

In this paper, we study electrostatic properties between two similar or oppositely charged surfaces immersed in an electrolyte solution by using the mean-field approach accounting for solvent polarization and non-uniform size effects. Applying a free energy formalism accounting for unequal ion sizes and orientational ordering of water dipoles, we derive coupled and self-consistent equations to calculate electrostatic properties between charged surfaces. Electrostatic properties for similarly charged surfaces depend on the counterion size but not on the coion size. Moreover, electrostatic potential and osmotic pressure between similarly charged surfaces are found to be increased with increasing counterion size. On the other hand, the corresponding ones between oppositely charged surfaces are related to both sizes of positive and negative ions. For oppositely charged surfaces, the electrostatic potential, number density of solvent molecules, and relative permittivity of an electrolyte having unequal ion sizes are not symmetric about the centerline between the charged surfaces. For either case, the consideration of solvent polarization results in a decrease in the electrostatic potential and the osmotic pressure compared to the case without the effect.

Charge Transport in LDPE Nanocomposites Part II—Computational Approach

Directory of Open Access Journals (Sweden)

Anh T. Hoang

2016-03-01

Full Text Available A bipolar charge transport model is employed to investigate the remarkable reduction in dc conductivity of low-density polyethylene (LDPE based material filled with uncoated nanofillers (reported in the first part of this work. The effect of temperature on charge transport is considered and the model outcomes are compared with measured conduction currents. The simulations reveal that the contribution of charge carrier recombination to the total transport process becomes more significant at elevated temperatures. Among the effects caused by the presence of nanoparticles, a reduced charge injection at electrodes has been found as the most essential one. Possible mechanisms for charge injection at different temperatures are therefore discussed.

Studies in Fat Grafting: Part II. Effects of Injection Mechanics on Material Properties of Fat

Science.gov (United States)

Atashroo, David; Raphel, Jordan; Chung, Michael T.; Paik, Kevin J.; Parisi-Amon, Andreina; McArdle, Adrian; Senarath-Yapa, Kshemendra; Zielins, Elizabeth R.; Tevlin, Ruth; Duldulao, Chris; Walmsley, Graham G.; Hu, Michael S.; Momeni, Arash; Domecus, Brian; Rimsa, Joe R.; Greenberg, Lauren; Gurtner, Geoffrey C.; Longaker, Michael T.; Wan, Derrick C.

2014-01-01

Background While fat grafting can address many soft tissue deficits, results remain inconsistent. In this study, we compared physical properties of fat following injection using an automated, low shear device or the modified Coleman technique. Methods Lipoaspirate was obtained from nine patients and processed for injection using either a modified Coleman technique or with an automated, low shear device. Fat was passed through a 2 mm cannula and compared to minimally processed fat. A rheometer was used to measure the storage modulus and shear rate at which tissues began to lose their solid-like properties. Viscosity was also measured and gross properties of treatment groups were qualitatively evaluated with a glass slide test. Results Fat injected through an automated, low shear device closely matched physical properties of minimally processed fat. The storage modulus (G′) of fat for the device group was greater than the modified Coleman group and the onset of breakdown was delayed. Similarly, viscosity measurement of fat from the automated device closely matched minimally processed fat and was greater than the modified Coleman group. Conclusions The physical properties of lipoaspirate processed using an automated, low shear device with a 2 mm cannula preserved the intactness of fat more than the modified Coleman technique. Our rheological data demonstrate less damage using an automated device compared to modified Coleman technique and potentially support its use for improved fat graft integrity. PMID:25028817

Aqueous lubricating properties of charged (ABC) and neutral (ABA) triblock copolymer chains

DEFF Research Database (Denmark)

Røn, Troels; Javakhishvili, Irakli; Patil, Navin J.

2014-01-01

Application of charged polymer chains as additives for lubricating neutral surfaces in aqueous envi- ronment, especially via polymer physisorption, is generally impeded by the electrostatic repulsion be- tween adjacent polymers on the surface. In this study, we have investigated the adsorption an...... improvement compared to fully charged polymer chains, e.g. poly(acrylic acid)- block -poly(2-methoxyethyl acrylate) (PAA- b -PMEA), which is attributed to dilution of charged moieties on the surface and subsequent improvement of the lubricating fi lm stability......Application of charged polymer chains as additives for lubricating neutral surfaces in aqueous envi- ronment, especially via polymer physisorption, is generally impeded by the electrostatic repulsion be- tween adjacent polymers on the surface. In this study, we have investigated the adsorption...... and aqueous lubricating properties of an amphiphilic triblock copolymer, comprised of a neutral poly(ethylene glycol) (PEG) block, a hydrophobic poly(2-methoxyethyl acrylate) (PMEA) block, and a charged poly(methacrylic acid) (PMAA) block, namely PEG- b -PMEA- b -PMAA. After adsorption onto a nonpolar...

Injection and temporary capture of a charged particle beam in an open magnetic configuration. Optimization of the configuration. Case of cylindrical symmetry: A mirror machine

International Nuclear Information System (INIS)

Capdequi-Peyranere, P.

1966-12-01

A study has been made of a new method of transverse injection of charged particles into a magnetic mirror configuration. This injection scheme permits the penetration and temporary capture by non-adiabatic effect of a particle beam of approximately 1 cm 2 cross-section. A theoretical study of the injection and capture is made in the approximation that space charge is negligible. The original programs for IBM 7094 computer calculations are described; these programs were used to obtain an optimization of the configuration. The results of a statistical numerical study of the optimum configuration are then given. This study indicates that, if the energy of the particles of the beam is about 1 per cent greater than a minimum penetration energy, the entire beam can be captured with an average capture length of 100 meters (50 reflections between the two mirrors). If the energy is about 4 per cent greater than the minimum penetration energy, the capture length is reduced to 40 meters. We have studied the distribution of energy transverse and longitudinal with the magnetic field for the population of captured particles. For the cases of injected molecular hydrogen ions or heavy CH 4 + ions, a study is made of the capture time of protons resulting from the dissociation of the ions by collisions with the neutral gas. Finally, we describe a model experiment using electrons designed to provide an experimental verification of the capture of the primary beam. (author) [fr

"Vivo para consumirla y la consumo para vivir" ["I live to inject and inject to live"]: high-risk injection behaviors in Tijuana, Mexico.

Science.gov (United States)

Strathdee, Steffanie A; Fraga, Wendy Davila; Case, Patricia; Firestone, Michelle; Brouwer, Kimberly C; Perez, Saida Gracia; Magis, Carlos; Fraga, Miguel Angel

2005-09-01

Injection drug use is a growing problem on the US-Mexico border, where Tijuana is situated. We studied the context of injection drug use among injection drug users (IDUs) in Tijuana to help guide future research and interventions. Guided in-depth interviews were conducted with 10 male and 10 female current IDUs in Tijuana. Topics included types of drug used, injection settings, access to sterile needles, and environmental influences. Interviews were taped, transcribed verbatim, and translated. Content analysis was conducted to identify themes. Of the 20 IDUs, median age and age at first injection were 30 and 18. Most reported injecting at least daily: heroin ("carga", "chiva", "negra"), methamphetamine ("crico", "cri-cri"), or both drugs combined. In sharp contrast to Western US cities, almost all regularly attended shooting galleries ("yongos" or "picaderos") because of the difficulties obtaining syringes and police oppression. Almost all shared needles/paraphernalia ["cuete" (syringe), "cacharros" (cookers), cotton from sweaters/socks (filters)]. Some reported obtaining syringes from the United States. Key themes included (1) pharmacies refusing to sell or charging higher prices to IDUs, (2) ample availability of used/rented syringes from "picaderos" (e.g., charging approximately 5 pesos or "10 drops" of drug), and (3) poor HIV/AIDS knowledge, such as beliefs that exposing syringes to air "kills germs." This qualitative study suggests that IDUs in Tijuana are at high risk of HIV and other blood-borne infections. Interventions are urgently needed to expand access to sterile injection equipment and offset the potential for a widespread HIV epidemic.

Estimation of the diameter-charge distribution in polydisperse electrically charged sprays of electrically insulating liquids

Energy Technology Data Exchange (ETDEWEB)

Rigit, A.R.H. [University of Sarawak, Faculty of Engineering, Kota Samarahan, Sarawak (Malaysia); Shrimpton, John S. [University of Southampton, Energy Technology Research Group, School of Engineering Sciences, Southampton (United Kingdom)

2009-06-15

The majority of scientific and industrial electrical spray applications make use of sprays that contain a range of drop diameters. Indirect evidence suggests the mean drop diameter and the mean drop charge level are usually correlated. In addition, within each drop diameter class there is every reason to suspect a distribution of charge levels exist for a particular drop diameter class. This paper presents an experimental method that uses the joint PDF of drop velocity and diameter, obtained from phase Doppler anemometry measurements, and directly obtained spatially resolved distributions of the mass and charge flux to obtain a drop diameter and charge frequency distribution. The method is demonstrated using several data-sets obtained from experimental measurements of steady poly-disperse sprays of an electrically insulating liquid produced with the charge injection technique. The space charge repulsion in the spray plume produces a hollow cone spray structure. In addition an approximate self-similarity is observed, with the maximum radial mass and charge flow occurring at r/d{proportional_to}200. The charge flux profile is slightly offset from the mass flux profile, and this gives direct evidence that the spray specific charge increases from approximately 20% of the bulk mean spray specific charge on the spray axis to approximately 200% of the bulk mean specific charge in the periphery of the spray. The results from the drop charge estimation model suggest a complex picture of the correlation between drop charge and drop diameter, with spray specific charge, injection velocity and orifice diameter all contributing to the shape of the drop diameter-charge distribution. Mean drop charge as a function of the Rayleigh limit is approximately 0.2, and is invariant with drop diameter and also across the spray cases tested. (orig.)

Estimation of the diameter-charge distribution in polydisperse electrically charged sprays of electrically insulating liquids

Science.gov (United States)

Rigit, A. R. H.; Shrimpton, John S.

2009-06-01

The majority of scientific and industrial electrical spray applications make use of sprays that contain a range of drop diameters. Indirect evidence suggests the mean drop diameter and the mean drop charge level are usually correlated. In addition, within each drop diameter class there is every reason to suspect a distribution of charge levels exist for a particular drop diameter class. This paper presents an experimental method that uses the joint PDF of drop velocity and diameter, obtained from phase Doppler anemometry measurements, and directly obtained spatially resolved distributions of the mass and charge flux to obtain a drop diameter and charge frequency distribution. The method is demonstrated using several data-sets obtained from experimental measurements of steady poly-disperse sprays of an electrically insulating liquid produced with the charge injection technique. The space charge repulsion in the spray plume produces a hollow cone spray structure. In addition an approximate self-similarity is observed, with the maximum radial mass and charge flow occurring at r/ d ~ 200. The charge flux profile is slightly offset from the mass flux profile, and this gives direct evidence that the spray specific charge increases from approximately 20% of the bulk mean spray specific charge on the spray axis to approximately 200% of the bulk mean specific charge in the periphery of the spray. The results from the drop charge estimation model suggest a complex picture of the correlation between drop charge and drop diameter, with spray specific charge, injection velocity and orifice diameter all contributing to the shape of the drop diameter-charge distribution. Mean drop charge as a function of the Rayleigh limit is approximately 0.2, and is invariant with drop diameter and also across the spray cases tested.

Photo-induced charge transfer at heterogeneous interfaces: Dye-sensitized tin disulfide, the theory and the experiment

International Nuclear Information System (INIS)

Lanzafame, J.M.

1993-01-01

The study of photo-induced charge transfer is an endeavor that spans the entire industrial period of man's history. Its great importance demands an ever greater understanding of its underlying principles. The work discussed here attempts to probe elementary aspects of the charge transfer process. Investigations into the theory of charge transfer reactions are made in an attempt to isolate the relevant parameters. An analytical discussion is made of a simple Golden Rule type rate equation to describe the transfer kinetics. Then a quantum simulation is carried out to follow the wavefunction propagation as a test of the applicability of the assumptions made in deriving the simpler rate equation. Investigation of charge transfer at surfaces is bet served by the application of ultrafast optical spectroscopies to probe carrier dynamics. A discussion of the properties of the short pulse laser systems employed is included along with a discussion of the different optical spectroscopies available. These tools are then brought to bear upon dye-sensitized SnS 2 , a model system for the study of charge injection processes. The unique properties of the semiconductor are discussed with respect to the charge transfer process. The unique properties of the semiconductor are discussed with respect to the charge transfer process. The optical experiments performed on the dye/SnS 2 systems elucidate the fundamental carrier dynamics and these dynamics are discussed within the theoretical framework to provide a complete picture of the charge transfer kinetics

Organic integrated circuits for information storage based on ambipolar polymers and charge injection engineering

Energy Technology Data Exchange (ETDEWEB)

Dell' Erba, Giorgio; Natali, Dario [Center for Nano Science and Technology PoliMi, Istituto Italiano di Tecnologia, Via Pascoli 70/3, 20133 Milano (Italy); Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Piazza L. da Vinci 32, 20133 Milano (Italy); Luzio, Alessandro; Caironi, Mario, E-mail: mario.caironi@iit.it, E-mail: yynoh@dongguk.edu [Center for Nano Science and Technology PoliMi, Istituto Italiano di Tecnologia, Via Pascoli 70/3, 20133 Milano (Italy); Kim, Juhwan; Khim, Dongyoon; Kim, Dong-Yu [Heeger Center for Advanced Materials, School of Materials Science and Engineering, Gwangju Institute of Science and Technology (GIST), 261 Cheomdan-gwagiro, Buk-gu, Gwangju 500-712 (Korea, Republic of); Noh, Yong-Young, E-mail: mario.caironi@iit.it, E-mail: yynoh@dongguk.edu [Department of Energy and Materials Engineering, Dongguk University, 26 Pil-dong, 3-ga, Jung-gu, Seoul 100-715 (Korea, Republic of)

2014-04-14

Ambipolar semiconducting polymers, characterized by both high electron (μ{sub e}) and hole (μ{sub h}) mobility, offer the advantage of realizing complex complementary electronic circuits with a single semiconducting layer, deposited by simple coating techniques. However, to achieve complementarity, one of the two conduction paths in transistors has to be suppressed, resulting in unipolar devices. Here, we adopt charge injection engineering through a specific interlayer in order to tune injection into frontier energy orbitals of a high mobility donor-acceptor co-polymer. Starting from field-effect transistors with Au contacts, showing a p-type unbalanced behaviour with μ{sub h} = 0.29 cm{sup 2}/V s and μ{sub e} = 0.001 cm{sup 2}/V s, through the insertion of a caesium salt interlayer with optimized thickness, we obtain an n-type unbalanced transistor with μ{sub e} = 0.12 cm{sup 2}/V s and μ{sub h} = 8 × 10{sup −4} cm{sup 2}/V s. We applied this result to the development of the basic pass-transistor logic building blocks such as inverters, with high gain and good noise margin, and transmission-gates. In addition, we developed and characterized information storage circuits like D-Latches and D-Flip-Flops consisting of 16 transistors, demonstrating both their static and dynamic performances and thus the suitability of this technology for more complex circuits such as display addressing logic.

Tuning electronic properties of graphene nanoflake polyaromatic hydrocarbon through molecular charge-transfer interactions

Science.gov (United States)

Sharma, Vaishali; Dabhi, Shweta D.; Shinde, Satyam; Jha, Prafulla K.

2018-05-01

By means of first principles calculation we have tuned the electronic properties of graphene nanoflake polyaromatic hydrocarbon via molecular charge transfer. Acceptor/donor Tetracyanoquinodimethane (TCNQ) and Tetrathiafulvalene (TTF) organic molecules are adsorbed on polyaromatic hydrocarbons (PAH) in order to introduce the charge transfer. The substrate's n- or p- type nature depends on the accepting/donating behavior of dopant molecules. Two different classes of PAH (extended form of triangulene) namely Bow-tie graphene nanoflake (BTGNF) and triangular zigzag graphene nanoflake (TZGNF). It is revealed that all the TCNQ and TTF modified graphene nanoflakes exhibit significant changes in HOMO-LUMO gap in range from 0.58 eV to 0.64 eV and 0.01 eV to 0.05 eV respectively. The adsorption energies are in the range of -0.05 kcal/mol to -2.6 kcal/mol. The change in work function is also calculated and discussed, the maximum charge transfer is for TCNQ adsorbed BTGNF. These alluring findings in the tuning of electronic properties will be advantageous for promoting graphene nanoflake polyaromatic hydrocarbon for their applications in electronic devices.

Low-charge-state linac

Energy Technology Data Exchange (ETDEWEB)

Shepard, K.W.; Kim, J.W.

1995-08-01

A design is being developed for a low-charge-state linac suitable for injecting ATLAS with a low-charge-state, radioactive beam. Initial work indicates that the existing ATLAS interdigital superconducting accelerating structures, together with the superconducting quadrupole transverse focussing element discussed above, provides a basis for a high-performance low-charge-state linac. The initial 2 or 3 MV of such a linac could be based on a normally-conducting, low-frequency RFQ, possibly combined with 24-MHz superconducting interdigital structures. Beam dynamics studies of the whole low-charge-state post-accelerator section were carried out in early FY 1995.

Performance Enhancement of Organic Light-Emitting Diodes Using Electron-Injection Materials of Metal Carbonates

Science.gov (United States)

Shin, Jong-Yeol; Kim, Tae Wan; Kim, Gwi-Yeol; Lee, Su-Min; Shrestha, Bhanu; Hong, Jin-Woong

2016-05-01

Performance of organic light-emitting diodes was investigated depending on the electron-injection materials of metal carbonates (Li2CO3 and Cs2CO3 ); and number of layers. In order to improve the device efficiency, two types of devices were manufactured by using the hole-injection material (Teflon-amorphous fluoropolymer -AF) and electron-injection materials; one is a two-layer reference device ( ITO/Teflon-AF/Alq3/Al ) and the other is a three-layer device (ITO/Teflon-AF/Alq3/metal carbonate/Al). From the results of the efficiency for the devices with hole-injection layer and electron-injection layer, it was found that the electron-injection layer affects the electrical properties of the device more than the hole-injection layer. The external-quantum efficiency for the three-layer device with Li2CO3 and Cs2CO3 layer is improved by approximately six and eight times, respectively, compared with that of the two-layer reference device. It is thought that a use of electron-injection layer increases recombination rate of charge carriers by the active injection of electrons and the blocking of holes.

Injection Related Background due to the Transverse Feedback

International Nuclear Information System (INIS)

Decker, F.J.; Akre, R.; Fisher, A.; Iverson, R.; Weaver, M.

2008-01-01

The background in the BaBar detector is especially high during injection, when most components are actually having reduced voltages. The situation is worse for the beam in High Energy Ring (HER) when the LER beam is present. It was found that the transverse feedback system plays an important role when stacking more charge on top of existing bunches. Lowering the feedback gain helped and it was realized later that the best scenario would be to gate off the feedback for only the one bunch, which got additional charge injected into it. The explanation is that the blown-up, but centered, original HER bunch plus the small injected off-axis bunch (each with half the charge) would stay in the ring if not touched, but the feedback system sees half the offset and wants to correct it, therefore disturbing and scraping the blown-up part

MOHOS-type memory performance using HfO2 nanoparticles as charge trapping layer and low temperature annealing

International Nuclear Information System (INIS)

Molina, Joel; Ortega, Rafael; Calleja, Wilfrido; Rosales, Pedro; Zuniga, Carlos; Torres, Alfonso

2012-01-01

Highlights: ► HfO 2 nanoparticles used as charge trapping layer in MOHOS memory devices. ► Increasing HfO 2 nanoparticles concentration enhances charge injection and trapping. ► Enhancement of memory performance with low temperature annealing. ► Charge injection is done without using any hot-carrier injection mechanism. ► Using injected charge density is better for comparison of scaled memory devices. - Abstract: In this work, HfO 2 nanoparticles (np-HfO 2 ) are embedded within a spin-on glass (SOG)-based oxide matrix and used as a charge trapping layer in metal–oxide–high-k–oxide–silicon (MOHOS)-type memory applications. This charge trapping layer is obtained by a simple sol–gel spin coating method after using different concentrations of np-HfO 2 and low temperature annealing (down to 425 °C) in order to obtain charge–retention characteristics with a lower thermal budget. The memory's charge trapping characteristics are quantized by measuring both the flat-band voltage shift of MOHOS capacitors (writing/erasing operations) and their programming retention times after charge injection while correlating all these data to np-HfO 2 concentration and annealing temperature. Since a large memory window has been obtained for our MOHOS memory, the relatively easy injection/annihilation (writing/erasing) of charge injected through the substrate opens the possibility to use this material as an effective charge trapping layer. It is shown that by using lower annealing temperatures for the charge trapping layer, higher densities of injected charge are obtained along with enhanced retention times. In conclusion, by using np-HfO 2 as charge trapping layer in memory devices, moderate programming and retention characteristics have been obtained by this simple and yet low-cost spin-coating method.

Room-Temperature Triple-Ligand Surface Engineering Synergistically Boosts Ink Stability, Recombination Dynamics, and Charge Injection toward EQE-11.6% Perovskite QLEDs.

Science.gov (United States)

Song, Jizhong; Li, Jinhang; Xu, Leimeng; Li, Jianhai; Zhang, Fengjuan; Han, Boning; Shan, Qingsong; Zeng, Haibo

2018-06-10

Developing low-cost and high-quality quantum dots (QDs) or nanocrystals (NCs) and their corresponding efficient light-emitting diodes (LEDs) is crucial for the next-generation ultra-high-definition flexible displays. Here, there is a report on a room-temperature triple-ligand surface engineering strategy to play the synergistic role of short ligands of tetraoctylammonium bromide (TOAB), didodecyldimethylammonium bromide (DDAB), and octanoic acid (OTAc) toward "ideal" perovskite QDs with a high photoluminescence quantum yield (PLQY) of >90%, unity radiative decay in its intrinsic channel, stable ink characteristics, and effective charge injection and transportation in QD films, resulting in the highly efficient QD-based LEDs (QLEDs). Furthermore, the QD films with less nonradiative recombination centers exhibit improved PL properties with a PLQY of 61% through dopant engineering in A-site. The robustness of such properties is demonstrated by the fabrication of green electroluminescent LEDs based on CsPbBr 3 QDs with the peak external quantum efficiency (EQE) of 11.6%, and the corresponding peak internal quantum efficiency (IQE) and power efficiency are 52.2% and 44.65 lm W -1 , respectively, which are the most-efficient perovskite QLEDs with colloidal CsPbBr 3 QDs as emitters up to now. These results demonstrate that the as-obtained QD inks have a wide range application in future high-definition QD displays and high-quality lightings. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Influence of layer charge and charge distribution of smectites on the flow behaviour and swelling of bentonites

Science.gov (United States)

Christidis, G.E.; Blum, A.E.; Eberl, D.D.

2006-01-01

The influence of layer charge and charge distribution of dioctahedral smectites on the rheological and swelling properties of bentonites is examined. Layer charge and charge distribution were determined by XRD using the LayerCharge program [Christidis, G.E., Eberl, D.D., 2003. Determination of layer charge characteristics of smectites. Clays Clay Miner. 51, 644-655.]. The rheological properties were determined, after sodium exchange using the optimum amount of Na2CO3, from free swelling tests. Rheological properties were determined using 6.42% suspensions according to industrial practice. In smectites with layer charges of - 0.425 to - 0.470 per half formula unit (phfu), layer charge is inversely correlated with free swelling, viscosity, gel strength, yield strength and thixotropic behaviour. In these smectites, the rheological properties are directly associated with the proportion of low charge layers. By contrast, in low charge and high charge smectites there is no systematic relation between layer charge or the proportion of low charge layers and rheological properties. However, low charge smectites yield more viscous suspensions and swell more than high charge smectites. The rheological properties of bentonites also are affected by the proportion of tetrahedral charge (i.e. beidellitic charge), by the existence of fine-grained minerals having clay size, such as opal-CT and to a lesser degree by the ionic strength and the pH of the suspension. A new method for classification of smectites according to the layer charge based on the XRD characteristics of smecites is proposed, that also is consistent with variations in rheological properties. In this classification scheme the term smectites with intermediate layer charge is proposed. ?? 2006 Elsevier B.V. All rights reserved.

Modulation of the electronic property of phosphorene by wrinkle and vertical electric field

Energy Technology Data Exchange (ETDEWEB)

Li, Yan; Wei, Zhongming, E-mail: zmwei@semi.ac.cn; Li, Jingbo, E-mail: jbli@semi.ac.cn [State Key Laboratory of Superlattice and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083 (China)

2015-09-14

The electronic properties of wrinkled phosphorene and its response to charge injection and external vertical electric field have been studied using first-principles calculations. It is found that small-size wrinkle systems have lower energy than wrinkle-free monolayer, suggesting that free-standing phosphorene spontaneously forms small protrusion on its nanosheet. The ratio of wrinkle height to curvature radius increases with enlarging height, indicating a promotion of field enhancement factor. Furthermore, the injected charges mostly distribute at peak and valley. Direct-to-indirect band-gap transition has been found for zigzag wrinkle with height of 14.81 Å. The band gaps of wrinkled nanosheets decrease almost linearly with increasing field, which is caused by charge separation of valence band maximum and conduction band minimum.

Materials Characterization at Utah State University: Facilities and Knowledge-base of Electronic Properties of Materials Applicable to Spacecraft Charging

Science.gov (United States)

Dennison, J. R.; Thomson, C. D.; Kite, J.; Zavyalov, V.; Corbridge, Jodie

2004-01-01

In an effort to improve the reliability and versatility of spacecraft charging models designed to assist spacecraft designers in accommodating and mitigating the harmful effects of charging on spacecraft, the NASA Space Environments and Effects (SEE) Program has funded development of facilities at Utah State University for the measurement of the electronic properties of both conducting and insulating spacecraft materials. We present here an overview of our instrumentation and capabilities, which are particularly well suited to study electron emission as related to spacecraft charging. These measurements include electron-induced secondary and backscattered yields, spectra, and angular resolved measurements as a function of incident energy, species and angle, plus investigations of ion-induced electron yields, photoelectron yields, sample charging and dielectric breakdown. Extensive surface science characterization capabilities are also available to fully characterize the samples in situ. Our measurements for a wide array of conducting and insulating spacecraft materials have been incorporated into the SEE Charge Collector Knowledge-base as a Database of Electronic Properties of Materials Applicable to Spacecraft Charging. This Database provides an extensive compilation of electronic properties, together with parameterization of these properties in a format that can be easily used with existing spacecraft charging engineering tools and with next generation plasma, charging, and radiation models. Tabulated properties in the Database include: electron-induced secondary electron yield, backscattered yield and emitted electron spectra; He, Ar and Xe ion-induced electron yields and emitted electron spectra; photoyield and solar emittance spectra; and materials characterization including reflectivity, dielectric constant, resistivity, arcing, optical microscopy images, scanning electron micrographs, scanning tunneling microscopy images, and Auger electron spectra. Further

Fabrication of Al2O3 Nano-Structure Functional Film on a Cellulose Insulation Polymer Surface and Its Space Charge Suppression Effect

Directory of Open Access Journals (Sweden)

Jian Hao

2017-10-01

Full Text Available Cellulose insulation polymer (paper/pressboard has been widely used in high voltage direct current (HVDC transformers. One of the most challenging issues in the insulation material used for HVDC equipment is the space charge accumulation. Effective ways to suppress the space charge injection/accumulation in insulation material is currently a popular research topic. In this study, an aluminium oxide functional film was deposited on a cellulose insulation pressboard surface using reactive radio frequency (RF magnetron sputtering. The sputtered thin film was characterized by the scanning electron microscopy/energy dispersive spectrometer (SEM/EDS, X-ray photoelectron spectroscopy (XPS, and X-ray diffraction (XRD. The influence of the deposited functional film on the dielectric properties and the space charge injection/accumulation behaviour was investigated. A preliminary exploration of the space charge suppression effect is discussed. SEM/EDS, XPS, and XRD results show that the nano-structured Al2O3 film with amorphous phase was successfully fabricated onto the fibre surface. The cellulose insulation pressboard surface sputtered by Al2O3 film has lower permittivity, conductivity, and dissipation factor values in the lower frequency (<103 Hz region. The oil-impregnated sputtered pressboard presents an apparent space-charge suppression effect. Compared with the pressboard sputtered with Al2O3 film for 90 min, the pressboard sputtered with Al2O3 film for 60 min had a better space charge suppression effect. Ultra-small Al2O3 particles (<10 nm grew on the surface of the larger nanoparticles. The nano-structured Al2O3 film sputtered on the fibre surface could act as a functional barrier layer for suppression of the charge injection and accumulation. This study offers a new perspective in favour of the application of insulation pressboard with a nano-structured function surface against space charge injection/accumulation in HVDC equipment.

Injection Molding and Mechanical Properties of Bio-Based Polymer Nanocomposites

Directory of Open Access Journals (Sweden)

Maria Chiara Mistretta

2018-04-01

Full Text Available The use of biodegradable/bio-based polymers is of great importance in addressing several issues related to environmental protection, public health, and new, stricter legislation. Yet some applications require improved properties (such as barrier or mechanical properties, suggesting the use of nanosized fillers in order to obtain bio-based polymer nanocomposites. In this work, bionanocomposites based on two different biodegradable polymers (coming from the Bioflex and MaterBi families and two different nanosized fillers (organo-modified clay and hydrophobic-coated precipitated calcium carbonate were prepared and compared with traditional nanocomposites with high-density polyethylene (HDPE as matrix. In particular, the injection molding processability, as well as the mechanical and rheological properties of the so-obtained bionanocomposites were investigated. It was found that the processability of the two biodegradable polymers and the related nanocomposites can be compared to that of the HDPE-based systems and that, in general, the bio-based systems can be taken into account as suitable alternatives.

MOHOS-type memory performance using HfO{sub 2} nanoparticles as charge trapping layer and low temperature annealing

Energy Technology Data Exchange (ETDEWEB)

Molina, Joel, E-mail: jmolina@inaoep.mx [National Institute of Astrophysics, Optics and Electronics. Electronics Department, Luis Enrique Erro 1, Tonantzintla, Puebla 72000 (Mexico); Ortega, Rafael; Calleja, Wilfrido; Rosales, Pedro; Zuniga, Carlos; Torres, Alfonso [National Institute of Astrophysics, Optics and Electronics. Electronics Department, Luis Enrique Erro 1, Tonantzintla, Puebla 72000 (Mexico)

2012-09-20

Highlights: Black-Right-Pointing-Pointer HfO{sub 2} nanoparticles used as charge trapping layer in MOHOS memory devices. Black-Right-Pointing-Pointer Increasing HfO{sub 2} nanoparticles concentration enhances charge injection and trapping. Black-Right-Pointing-Pointer Enhancement of memory performance with low temperature annealing. Black-Right-Pointing-Pointer Charge injection is done without using any hot-carrier injection mechanism. Black-Right-Pointing-Pointer Using injected charge density is better for comparison of scaled memory devices. - Abstract: In this work, HfO{sub 2} nanoparticles (np-HfO{sub 2}) are embedded within a spin-on glass (SOG)-based oxide matrix and used as a charge trapping layer in metal-oxide-high-k-oxide-silicon (MOHOS)-type memory applications. This charge trapping layer is obtained by a simple sol-gel spin coating method after using different concentrations of np-HfO{sub 2} and low temperature annealing (down to 425 Degree-Sign C) in order to obtain charge-retention characteristics with a lower thermal budget. The memory's charge trapping characteristics are quantized by measuring both the flat-band voltage shift of MOHOS capacitors (writing/erasing operations) and their programming retention times after charge injection while correlating all these data to np-HfO{sub 2} concentration and annealing temperature. Since a large memory window has been obtained for our MOHOS memory, the relatively easy injection/annihilation (writing/erasing) of charge injected through the substrate opens the possibility to use this material as an effective charge trapping layer. It is shown that by using lower annealing temperatures for the charge trapping layer, higher densities of injected charge are obtained along with enhanced retention times. In conclusion, by using np-HfO{sub 2} as charge trapping layer in memory devices, moderate programming and retention characteristics have been obtained by this simple and yet low-cost spin-coating method.

Experimental Investigation of Charging Properties of Interstellar Type Silica Dust Grains by Secondary Electron Emissions

Science.gov (United States)

Tankosic, D.; Abbas, M. M.

2013-01-01

The dust charging by electron impact is an important dust charging processes in astrophysical and planetary environments. Incident low energy electrons are reflected or stick to the grains charging the dust grains negatively. At sufficiently high energies electrons penetrate the grains, leading to excitation and emission of electrons referred to as secondary electron emission (SEE). Available classical theoretical models for calculations of SEE yields are generally applicable for neutral, planar, or bulk surfaces. These models, however, are not valid for calculations of the electron impact charging properties of electrostatically charged micron/submicron-size dust grains in astrophysical environments. Rigorous quantum mechanical models are not yet available, and the SEE yields have to be determined experimentally for development of more accurate models for charging of individual dust grains. At the present time, very limited experimental data are available for charging of individual micron-size dust grains, particularly for low energy electron impact. The experimental results on individual, positively charged, micron-size lunar dust grains levitated carried out by us in a unique facility at NASA-MSFC, based on an electrodynamic balance, indicate that the SEE by electron impact is a complex process. The electron impact may lead to charging or discharging of dust grains depending upon the grain size, surface potential, electron energy, electron flux, grain composition, and configuration (Abbas et al, 2010, 2012). In this paper, we discuss SEE charging properties of individual micron-size silica microspheres that are believed to be analogs of a class of interstellar dust grains. The measurements indicate charging of the 0.2m silica particles when exposed to 25 eV electron beams and discharging when exposed to higher energy electron beams. Relatively large size silica particles (5.2-6.82m) generally discharge to lower equilibrium potentials at both electron energies

Effects of Direct Fuel Injection Strategies on Cycle-by-Cycle Variability in a Gasoline Homogeneous Charge Compression Ignition Engine: Sample Entropy Analysis

Directory of Open Access Journals (Sweden)

Jacek Hunicz

2015-01-01

Full Text Available In this study we summarize and analyze experimental observations of cyclic variability in homogeneous charge compression ignition (HCCI combustion in a single-cylinder gasoline engine. The engine was configured with negative valve overlap (NVO to trap residual gases from prior cycles and thus enable auto-ignition in successive cycles. Correlations were developed between different fuel injection strategies and cycle average combustion and work output profiles. Hypothesized physical mechanisms based on these correlations were then compared with trends in cycle-by-cycle predictability as revealed by sample entropy. The results of these comparisons help to clarify how fuel injection strategy can interact with prior cycle effects to affect combustion stability and so contribute to design control methods for HCCI engines.

Setting up charging electric stations within residential communities in current China: Gaming of government agencies and property management companies

International Nuclear Information System (INIS)

Wu, Tian; Ma, Lin; Mao, Zhonggen; Ou, Xunmin

2015-01-01

The difficulty of charging electric vehicles (EVs) is now hindering their further development. Governments generally choose to build stations for home charging (including piles) within residential communities. Given the conflict of interest between various government agencies and property management companies, constructing a charging station within residential communities would result in welfare loss for the property management companies and therefore lead to the principal–agent problem. This paper constructs a two-period imperfect information game theory model to study the moral hazard involved in this issue and government agencies' optimal choice. In the analytic solution of the model, we find that the optimal choice for a farsighted government agency is to constantly improve the incentive mechanism and introduce charging stations only when the conflict of interest is eliminated. Any benefits derived from government regulations by force would prove short-lived. The government should focus on long-term returns in the development of EVs, and its optimal mechanism should be designed to mitigate the principal–agent problem of property management companies, thereby accelerate the progress of EV charging infrastructure and improve overall social welfare. - Highlights: • The charging of electric vehicles (EVs) is hindering their use. • A game theory model is used for analysis of EV charging station construction. • Charging stations are in residential communities in China. • Government agencies are constantly improving incentive mechanisms

Charge carrier dynamics investigation of CuInS{sub 2} quantum dots films using injected charge extraction by linearly increasing voltage (i-CELIV): the role of ZnS Shell

Energy Technology Data Exchange (ETDEWEB)

Bi, Ke; Sui, Ning; Zhang, Liquan; Wang, Yinghui, E-mail: yinghui-wang@outlook.com; Liu, Qinghui, E-mail: liuqinghui@jlu.edu.cn; Tan, Mingrui [Jilin University, Femtosecond Laser Laboratory, Key Laboratory of Physics and Technology for Advanced Batteries (Ministry of Education), College of Physics (China); Zhou, Qiang [Jilin University, Key Laboratory of Superhard Materials, College of Physics (China); Zhang, Hanzhuang, E-mail: zhanghz@jlu.edu.cn [Jilin University, Femtosecond Laser Laboratory, Key Laboratory of Physics and Technology for Advanced Batteries (Ministry of Education), College of Physics (China)

2016-12-15

The role of ZnS shell on the photo-physical properties within CuInS{sub 2}/ZnS quantum dots (QDs) is carefully studied in optoelectronic devices. Linearly increasing voltage technique has been employed to investigate the charge carrier dynamics of both CuInS{sub 2} and CuInS{sub 2}/ZnS QDs films. This study shows that charge carriers follow a similar behavior of monomolecular recombination in this film, with their charge transfer rate correlates to the increase of applied voltage. It turns out that the ZnS shell could affect the carrier diffusion process through depressing the trapping states and would build up a potential barrier.

Relation between microstructure and dielectric breakdown in the case of aluminous ceramics (SEMM method); Comportement d'alumines face a l'injection de charges. Relation microstructure - claquage dielectrique - mesure des charges d'influence (methode SEMM)

Energy Technology Data Exchange (ETDEWEB)

Liebault, J.

1999-02-01

The dielectric breakdown is strongly linked to the injection and the accumulation of charges in a non-conducting material. The physics of charged insulators proposes mechanisms of trapping and transport of charges in aluminium oxides by considering defects as localization sources of charges and of energy. In order to measure the influence of defects on dielectric breakdown, various aluminous ceramics have been elaborated. The nature and the quantity of defects have been characterized by the nature and the rate of impurities, by porosity, by the quantity of grain boundaries and by the presence and distribution of secondary phases. These materials have undergone breakdown tests. The dielectric rigidity depends strongly on the nature and the distribution of crystallographic defects (vacancy, interstitial ions and dislocation), on the other hand porosity below 5% has no influence. The doping of an alumina ceramic containing less than 100 ppm of impurities implies a diminution of its dielectric rigidity. The measurement of the SEMM (scanning electron microscopy mirror) effect allows the characterization of insulating materials. This method permits the evaluation of the ability for materials to trap charges, it gives information about the charge kinetic of trapping, charge localization and the energy levels of traps. (A.C.)

Operational experience with the Fermilab 150 GeV injection kicker

International Nuclear Information System (INIS)

Trendler, R.C.

1985-01-01

The Fermilab E17 injection kicker has been in operation for more than 12000 filament hours and has logged almost 350,000 pulses since commissioning without major failure. The kicker system uses EEV 1193B and 1193C double-ended thyratrons in the MAIN, CLIP and DUMP configuration. In typical operation, the pulser produces 4800 A, 20 μs pulses at a charging voltage of 60kV and is capable of operating at a 80kV charging voltage. Any failure of the injection process can cause the Tevatron cryogenic magnets to quench. This includes any misfires of the injection kicker. Considerable effort was made to maximize reliability and provide interlocks to limit the problems that could happen from injection kicker misfires. The operating experience and reliability of the EEV thyratron will be discussed. Also, the use of the fiber optics, unique charging power supplies, and unusual digital interlocks and the role they play in improved reliability will be discussed

Charge injection and transport in quantum confined and disordered systems

NARCIS (Netherlands)

Houtepen, A.J.

2007-01-01

Quantum dots and conducting polymers are modern semiconductors with a high potential for applications such as lasers, LEDs, displays, solar cells etc. These applications require the controlled addition of charge carriers into the material and knowledge of the details of charge transport. This thesis

Effect of different photoanode nanostructures on the initial charge separation and electron injection process in dye sensitized solar cells: A photophysical study with indoline dyes

Energy Technology Data Exchange (ETDEWEB)

Idígoras, Jesús [Nanostructured Solar Cells Group, Department of Physical, Chemical and Natural Systems, Universidad Pablo de Olavide, Ctra. Utrera, km 1, ES-41013 Seville (Spain); Sobuś, Jan [NanoBioMedical Centre, Adam Mickiewicz University, Umultowska 85, 61-614 Poznań (Poland); Quantum Electronics Laboratory, Faculty of Physics, Adam Mickiewicz University in Poznań, Umultowska 85, 61-614 Poznań (Poland); Jancelewicz, Mariusz [NanoBioMedical Centre, Adam Mickiewicz University, Umultowska 85, 61-614 Poznań (Poland); Azaceta, Eneko; Tena-Zaera, Ramon [Materials Division, IK4-CIDETEC, Parque Tecnológico de San Sebastián, Paseo Miramón 196, Donostia-San Sebastián, 20009 (Spain); Anta, Juan A. [Nanostructured Solar Cells Group, Department of Physical, Chemical and Natural Systems, Universidad Pablo de Olavide, Ctra. Utrera, km 1, ES-41013 Seville (Spain); Ziółek, Marcin, E-mail: marziol@amu.edu.pl [Quantum Electronics Laboratory, Faculty of Physics, Adam Mickiewicz University in Poznań, Umultowska 85, 61-614 Poznań (Poland)

2016-02-15

Ultrafast and fast charge separation processes were investigated for complete cells based on several ZnO-based photoanode nanostructures and standard TiO{sub 2} nanoparticle layers sensitized with the indoline dye coded D358. Different ZnO morphologies (nanoparticles, nanowires, mesoporous), synthesis methods (hydrothermal, gas-phase, electrodeposition in aqueous media and ionic liquid media) and coatings (ZnO–ZnO core–shell, ZnO–TiO{sub 2} core–shell) were measured by transient absorption techniques in the time scale from 100 fs to 100 μs and in the visible and near-infrared spectral range. All of ZnO cells show worse electron injection yields with respect to those with standard TiO{sub 2} material. Lower refractive index of ZnO than that of TiO{sub 2} is suggested to be an additional factor, not considered so far, that can decrease the performance of ZnO-based solar cells. Evidence of the participation of the excited charge transfer state of the dye in the charge separation process is provided here. The lifetime of this state in fully working devices extends from several ps to several tens of ps, which is much longer than the typically postulated electron injection times in all-organic dye-sensitized solar cells. The results here provided, comprising a wide variety of morphologies and preparation methods, point to the universality of the poor performance of ZnO as photoanode material with respect to standard TiO{sub 2}. - Highlights: • Wide variety of morphologies and preparation methods has been checked for ZnO cells. • All ZnO cells work worse than TiO{sub 2} ones. • Effective refractive index might be an additional factor in solar cell performance. • Excited charge transfer state of indoline dyes participates in the charge separation.

Low-charge-state RFQ injector

Energy Technology Data Exchange (ETDEWEB)

Shepard, K.W.; Kim, J.W.

1995-08-01

Preliminary design work was done for a short, normally-conducting RFQ entrance section for a low-charge-state linac. Early results indicate that a low- frequency (12 MHz) RFQ, operated on a high-voltage platform, and injected with a pre-bunched beam, can provide ATLAS quality beams of ions of charge-to-mass ratio less than 1/132.

Experimental investigation concerning the influence of fuel type and properties on the injection and atomization of liquid biofuels in an optical combustion chamber

International Nuclear Information System (INIS)

Galle, J.; Defruyt, S.; Van de Maele, C.; Rodriguez, R. Piloto; Denon, Q.; Verliefde, A.; Verhelst, S.

2013-01-01

Due to the scarcity of fossil fuels and the future stringent emission limits, there is an increasing interest for the use of renewable biofuels in compression ignition engines. However, these fuels have different physical, chemical and thermodynamic properties affecting atomization, spray development and combustion processes. The results reported in this paper have been obtained by experimentation with a constant volume combustion chamber. The influences of physical fuel properties on injections under non-evaporating conditions are studied, using a pump-line-nozzle system from a medium speed diesel engine with injection pressures up to 1200 bar, by changing the fuel type and temperature. Experiments were conducted for diesel, biodiesel, straight vegetable oils and animal fats. Injection pressure and needle lift measurements were analyzed. A high speed camera was used to visualize the spray, which enabled us to study the spray penetration and spray angle. Our results show that the fuel temperature is an important parameter to control because it significantly affects the fuel properties. Both the injection timing and injection duration are affected by the fuel properties. The influences of these properties on the spray development were less pronounced. At low temperatures, a strongly deteriorated atomization of oils and fats was observed. -- Highlights: • Spray measurements in an optical combustion chamber. • Influence on the injections system is compared for different bio-fuels. •Temperature effects the fuel properties, with strong influence on the injection system. • Viscosity has significant influence on atomization, especially for viscous fuels. • No difference for spray penetration and angle unlike the mass distribution

The effect of various quantum mechanically derived partial atomic charges on the bulk properties of chloride-based ionic liquids

Energy Technology Data Exchange (ETDEWEB)

Zolghadr, Amin Reza, E-mail: arzolghadr@shirazu.ac.ir [Department of Chemistry, Shiraz University, Shiraz 71946-84795 (Iran, Islamic Republic of); Ghatee, Mohammad Hadi [Department of Chemistry, Shiraz University, Shiraz 71946-84795 (Iran, Islamic Republic of); Moosavi, Fatemeh [Department of Chemistry, Ferdowsi University of Mashhad, Mashhad 91779 (Iran, Islamic Republic of)

2016-08-22

Partial atomic charges using various quantum mechanical calculations for [C{sub n}mim]Cl (n = 1, 4) ionic liquids (ILs) are obtained and used for development of molecular dynamics simulation (MD) force fields. The isolated ion pairs are optimized using HF, B3LYP, and MP2 methods for electronic structure with 6-311++G(d,p) basis set. Partial atomic charges are assigned to the atomic center with CHELPG and NBO methods. The effect of these sets of partial charges on the static and dynamic properties of ILs is evaluated by performing a series of MD simulations and comparing the essential thermodynamic properties with the available experimental data and available molecular dynamics simulation results. In contrast to the general trends reported for ionic liquids with BF{sub 4}, PF{sub 6}, and iodide anions (in which restrained electrostatic potential (RESP) charges are preferred), partial charges derived by B3LYP-NBO method are relatively good in prediction of the structural, dynamical, and thermodynamic energetic properties of the chloride based ILs.

Structural and electronic properties of Si/SiO2 MOS structures with aligned 3C-SiC nanocrystals in the oxide

International Nuclear Information System (INIS)

Pongracz, A.; Battistig, G.; Duecso, Cs.; Josepovits, K.V.; Deak, P.

2007-01-01

Our group previously proved that a simple reactive annealing in CO containing gas produces 3C-SiC nanocrystals, which are epitaxially and void-free aligned in the Si substrate. By a further thermal oxidation step, these nanocrystals can be lifted from the Si and incorporated into the SiO 2 matrix, thereby creating a promising structure for charge storage. In this work the structural and electrical properties of such systems with nanocrystalline SiC will be presented. Prototype MOS structures with 3C-SiC nanocrystals were produced for current-voltage and capacitance-voltage measurements. The results indicate that the high-temperature annealing did not damage the MOS structure, despite the fact that the CO annealing changed the electrical properties of the system. There was a positive charge accumulation and a reversible carrier injection observed in the structure. We assume that the positive charges originated from oxygen vacancies and the charge injection is related to the presence of SiC nanocrystals

Measured emittance dependence on injection method in laser plasma accelerators

Science.gov (United States)

Barber, Samuel; van Tilborg, Jeroen; Schroeder, Carl; Lehe, Remi; Tsai, Hai-En; Swanson, Kelly; Steinke, Sven; Nakamura, Kei; Geddes, Cameron; Benedetti, Carlo; Esarey, Eric; Leemans, Wim

2017-10-01

The success of many laser plasma accelerator (LPA) based applications relies on the ability to produce electron beams with excellent 6D brightness, where brightness is defined as the ratio of charge to the product of the three normalized emittances. As such, parametric studies of the emittance of LPA generated electron beams are essential. Profiting from a stable and tunable LPA setup, combined with a carefully designed single-shot transverse emittance diagnostic, we present a direct comparison of charge dependent emittance measurements of electron beams generated by two different injection mechanisms: ionization injection and shock induced density down-ramp injection. Notably, the measurements reveal that ionization injection results in significantly higher emittance. With the down-ramp injection configuration, emittances less than 1 micron at spectral charge densities up to 2 pC/MeV were measured. This work was supported by the U.S. DOE under Contract No. DE-AC02-05CH11231, by the NSF under Grant No. PHY-1415596, by the U.S. DOE NNSA, DNN R&D (NA22), and by the Gordon and Betty Moore Foundation under Grant ID GBMF4898.

High-Fidelity Simulations of Electrically-Charged Atomizing Diesel-Type Jets

Science.gov (United States)

Gaillard, Benoit; Owkes, Mark; van Poppel, Bret

2015-11-01

Combustion of liquid fuels accounts for over a third of the energy usage today. Improving efficiency of combustion systems is critical to meet the energy needs while limiting environmental impacts. Additionally, a shift away from traditional fossil fuels to bio-derived alternatives requires fuel injection systems that can atomize fuels with a wide range of properties. In this work, the potential benefits of electrically-charged atomization is investigated using numerical simulations. Particularly, the electrostatic forces on the hydrodynamic jet are quantified and the impact of the forces is analyzed by comparing simulations of Diesel-type jets at realistic flow conditions. The simulations are performed using a state-of-the-art numerical framework that globally conserves mass, momentum, and the electric charge density even at the gas-liquid interface where discontinuities exist.

Charge transport in non-polar and semi-polar III-V nitride heterostructures

International Nuclear Information System (INIS)

Konar, Aniruddha; Verma, Amit; Fang, Tian; Zhao, Pei; Jana, Raj; Jena, Debdeep

2012-01-01

Compared to the intense research focus on the optical properties, the transport properties in non-polar and semi-polar III-nitride semiconductors remain relatively unexplored to date. The purpose of this paper is to discuss charge-transport properties in non-polar and semi-polar orientations of GaN in a comparative fashion to what is known for transport in polar orientations. A comprehensive approach is adopted, starting from an investigation of the differences in the electronic bandstructure along different polar orientations of GaN. The polarization fields along various orientations are then discussed, followed by the low-field electron and hole mobilities. A number of scattering mechanisms that are specific to non-polar and semi-polar GaN heterostructures are identified, and their effects are evaluated. Many of these scattering mechanisms originate due to the coupling of polarization with disorder and defects in various incarnations depending on the crystal orientation. The effect of polarization orientation on carrier injection into quantum-well light-emitting diodes is discussed. This paper ends with a discussion of orientation-dependent high-field charge-transport properties including velocity saturation, instabilities and tunneling transport. Possible open problems and opportunities are also discussed. (paper)

The effect of charged groups on hydrophilic monolithic stationary phases on their chromatographic properties.

Science.gov (United States)

Li, Haibin; Liu, Chusheng; Wang, Qiqin; Zhou, Haibo; Jiang, Zhengjin

2016-10-21

In order to investigate the effect of charged groups present in hydrophilic monolithic stationary phases on their chromatographic properties, three charged hydrophilic monomers, i.e. N,N-dimethyl-N-acryloyloxyethyl-N-(3-sulfopropyl)ammonium betaine (SPDA), [2-(acryloyloxy)ethyl]trimethylammonium chloride (AETA), and 3-sulfopropyl acrylate potassium salt (SPA) were co-polymerized with the crosslinker N,N'-methylenebisacrylamide (MBA), respectively. The physicochemical properties of the three resulting charged hydrophilic monolithic columns were evaluated using scanning electron microscopy, ζ-potential analysis and micro-HPLC. High column efficiency was obtained on the three monolithic columns at a linear velocity of 1mm/s using thiourea as test compound. Comparative characterization of the three charged HILIC phases was then carried out using a set of model compounds, including nucleobases, nucleosides, benzoic acid derivatives, phenols, β-blockers and small peptides. Depending on the combination of stationary phase/mobile phase/solute, both hydrophilic interaction and other potential secondary interactions, including electrostatic interaction, hydrogen-bonding interaction, molecular shape selectivity, could contribute to the over-all retention of the analytes. Because of the strong electrostatic interaction provided by the quaternary ammonium groups in the poly (AETA-co-MBA) monolith, this cationic HILIC monolith exhibited the strongest retention for benzoic acid derivatives and small peptides with distorted peak shapes and the weakest retention for basic β-blockers. The sulfonyl groups on the poly (SPA-co-MBA) hydrophilic monolith could provide strong electrostatic attraction and hydrogen bonding for positively charged analytes and hydrogen-donor/acceptor containing analytes, respectively. Therefore, basic drugs, nucleobases and nucleotides exhibited the strongest retention on this anionic monolith. Because of the weak but distinct cation exchange properties of

Modifications of Fowler-Nordheim injection characteristics in γ irradiated MOS devices

International Nuclear Information System (INIS)

Scarpa, A.; Paccagnella, A.; Montera, F.; Candelori, A.; Ghidini, G.; Fuochi, P.G.

1998-01-01

In this work the authors have investigated how gamma irradiation affects the tunneling conduction mechanism of a 20 nm thick oxide in MOS capacitors. The radiation induced positive charge is rapidly compensated by the injected electrons, and does not impact the gate current under positive injection after the first current-voltage measurement. Only a transient stress induced leakage current at low gate bias is observed. Instead, a radiation induced negative charge has been observed near the polysilicon gate, which enhances the gate voltage needed for Fowler-Nordheim conduction at negative gate bias. No time decay of this charge has been observed. Such charges slightly modify the trapping kinetics of negative charge during subsequent electrical stresses performed at constant current condition

The isolation and characterisation of jacalin [Artocarpus heterophyllus (jackfruit) lectin] based on its charge properties.

Science.gov (United States)

Kabir, S

1995-02-01

Jackfruit extracts contain a protein termed jacalin which possesses diverse biological properties. A detailed analysis of its charge properties has been lacking. The present investigation was initiated to study isoelectric properties of jacalin in detail and to isolate a single isoform of jacalin. Jacalin was isolated from jackfruit extracts by affinity chromatography on immunoglobulin-A immobilised to Sepharose 4B. Various techniques such as ion-exchange chromatography, isoelectric focusing (IEF) on polyacrylamide gels and preparative liquid IEF with the Rotofor cell were used. When analysed by IEF on thin layer polyacrylamide gels, jacalin was resolved into 35 bands over a pH range of 5.0-8.5. Upon SDS-PAGE in the second dimension all these charge species gave rise to only two-bands at 12 and 15.4 kDa. The lectin was mostly eluted with 50 and 100 mM sodium chloride when jackfruit extracts were fractionated on an anion-exchange column of DEAE-cellulose. In a single 6 hour run by preparative IEF with the Rotofor cell in the pH range of 3-9.5, it has been possible to isolate pure jacalin fractions containing fewer number of charged isomers. A single jacalin isoform was isolated by subjecting a Rotofor fraction containing fewer charged species to preparative IEF on thin layer polyacrylamide gel and eluting the band of interest from the gel. The isolated jacalin isoform was biologically active as it agglutinated erythrocytes. The study reveals the complexity of jacalin as it exists as multiple charge isomers over a broad pH range. By performing preparative IEF in solution as well as in thin layer polyacrylamide gels, it was possible to isolate a single jacalin isoform with the retention of biological activity.

Measurement of Neutrino Induced, Charged Current, Charged Pion Production

Energy Technology Data Exchange (ETDEWEB)

Wilking, Michael Joseph [Univ. of Colorado, Boulder, CO (United States)

2009-05-01

Neutrinos are among the least understood particles in the standard model of particle physics. At neutrino energies in the 1 GeV range, neutrino properties are typically determined by observing the outgoing charged lepton produced in a charged current quasi-elastic interactions. The largest charged current background to these measurements comes from charged current pion production interactions, for which there is very little available data.

Improved charge trapping properties by embedded graphene oxide quantum-dots for flash memory application

Science.gov (United States)

Jia, Xinlei; Yan, Xiaobing; Wang, Hong; Yang, Tao; Zhou, Zhenyu; Zhao, Jianhui

2018-06-01

In this work, we have investigated two kinds of charge trapping memory devices with Pd/Al2O3/ZnO/SiO2/p-Si and Pd/Al2O3/ZnO/graphene oxide quantum-dots (GOQDs)/ZnO/SiO2/p-Si structure. Compared with the single ZnO sample, the memory window of the ZnO-GOQDs-ZnO sample reaches a larger value (more than doubled) of 2.7 V under the sweeping gate voltage ± 7 V, indicating a better charge storage capability and the significant charge trapping effects by embedding the GOQDs trapping layer. The ZnO-GOQDs-ZnO devices have better date retention properties with the high and low capacitances loss of ˜ 1.1 and ˜ 6.9%, respectively, as well as planar density of the trapped charges of 1.48 × 1012 cm- 2. It is proposed that the GOQDs play an important role in the outstanding memory characteristics due to the deep quantum potential wells and the discrete distribution of the GOQDs. The long date retention time might have resulted from the high potential barrier which suppressed both the back tunneling and the leakage current. Intercalating GOQDs in the memory device is a promising method to realize large memory window, low-power consumption and excellent retention properties.

Investigation of the Impact of Fuel Properties on Particulate Number Emission of a Modern Gasoline Direct Injection Engine

Energy Technology Data Exchange (ETDEWEB)

McCormick, Robert L [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Fioroni, Gina [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Fatouraie, Mohammad [Robert Bosch LLC; Frommherz, Mario [Robert Bosch LLC; Mosburger, Michael [Robert Bosch LLC; Chapman, Elana [General Motors LLC; Li, Sharon [General Motors LLC

2018-04-03

Gasoline Direct Injection (GDI) has become the preferred technology for spark-ignition engines resulting in greater specific power output and lower fuel consumption, and consequently reduction in CO2 emission. However, GDI engines face a substantial challenge in meeting new and future emission limits, especially the stringent particle number (PN) emissions recently introduced in Europe and China. Studies have shown that the fuel used by a vehicle has a significant impact on engine out emissions. In this study, nine fuels with varying chemical composition and physical properties were tested on a modern turbo-charged side-mounted GDI engine with design changes to reduce particulate emissions. The fuels tested included four fuels meeting US certification requirements; two fuels meeting European certification requirements; and one fuel meeting China 6 certification requirements being proposed at the time of this work. Two risk safeguard fuels (RSG), representing the properties of worst case market fuels in Europe and China, were also included. The particle number concentration of the solid particulates was measured in the engine-out exhaust flow at steady state engine operations with load and speed sweeps, and semi-transient load steps. The test results showed a factor of 6 PN emission difference among all certification fuels tested. Combined with detailed fuel analyses, this study evaluated important factors (such as oxygenates, carbon chain length and thermo-physical properties) that cause PN emissions which were not included in PMI index. A linear regression was performed to develop a PN predictive model which showed improved fitting quality than using PMI.

41 CFR 102-36.285 - May we charge for personal property transferred to another federal agency?

Science.gov (United States)

2010-07-01

... Property Management Federal Property Management Regulations System (Continued) FEDERAL MANAGEMENT... general fund of the Treasury or appropriated therefrom but by law reimbursable from assessment, tax, or... corporation. (b) You may charge for direct costs you incurred incident to the transfer, such as packing...

Effect of turbo charging and steam injection methods on the performance of a Miller cycle diesel engine (MCDE)

International Nuclear Information System (INIS)

Gonca, Guven; Sahin, Bahri

2017-01-01

Highlights: • Performance of a diesel engine is simulated by finite time thermodynamics. • Effect of steam injection on performance of a Miller cycle engine is examined. • Model results are verified with the experimental data with less than 7% error. - Abstract: In this study, application of the steam injection method (SIM), Miller cycle (MC) and turbo charging (TC) techniques into a four stroke, direct-injection diesel engine has been numerically and empirically conducted. NOx emissions have detrimental influences on the environment and living beings. They are formed at the high temperatures, thus the Diesel engines are serious NOx generation sources since they have higher compression ratios and higher combustion temperatures. The international regulations have decreased the emission limits due to environmental reasons. The Miller cycle (MC) application and steam injection method (SIM) have been popular to abate NOx produced from the internal combustion engines (ICEs), in the recent years. However, the MC application can cause a reduction in power output. The most known technique which maximizes the engine power and abates exhaust emissions is TC. Therefore, if these three techniques are combined, the power loss can be tolerated and pollutant emissions can be minimized. While the application of the MC and SIM causes to diminish in the brake power and brake thermal efficiency of the engine up to 6.5% and 10%, the TC increases the brake power and brake thermal efficiency of the engine up to 18% and 12%. The experimental and theoretical results have been compared in terms of the torque, the specific fuel consumption (SFC), the brake power and the brake thermal efficiency. The results acquired from theoretical modeling have been validated with empirical data with less than 7% maximum error. The results showed that developed combination can increase the engine performance and the method can be easily applied to the Diesel engines.

Effect of hydrogen charging on the mechanical properties of medium strength aluminium alloys 2091 and 2014

DEFF Research Database (Denmark)

Bandopadhyay, A.; Ambat, Rajan; Dwarakadasa, E.S.

1992-01-01

Cathodic hydrogen charging in 3.5% NaCl solution altered the mechanical properties of 2091-T351 (Al-Cu-Li-Mg-Zr) determined by a slow (10(-3)/s) strain rate tensile testing technique. UTS and YS decreased in the caw of 2091-T351 and 2014-T6(Al-Cu-Mn-Si-Mg) with increase in charging current density....... Elongation showed a decrease with increase in charging current density for both the alloys. However, elongation occurring throughout the gauge length in uncharged specimens changed over to localized deformation, thus increasing the reduction in area in charged specimens. A transition in fracture mode from...

The effect of hole transporting layer in charge accumulation properties of p-i-n perovskite solar cells

Directory of Open Access Journals (Sweden)

Fedros Galatopoulos

2017-07-01

Full Text Available The charge accumulation properties of p-i-n perovskite solar cells were investigated using three representative organic and inorganic hole transporting layer (HTL: (a Poly(3,4-ethylenedioxythiophene-poly(styrenesulfonate (PEDOT:PSS, Al 4083, (b copper-doped nickel oxide (Cu:NiOx, and (c Copper oxide (CuO. Through impedance spectroscopy analysis and modelling, it is shown that charge accumulation is decreased in the HTL/perovskite interface, between PEDOT:PSS to Cu:NiOx and CuO. This was indicative from the decrease in double layer capacitance (Cdl and interfacial charge accumulation capacitance (Cel, resulting in an increase to recombination resistance (Rrec, thus decreased charge recombination events between the three HTLs. Through AFM measurements, it is also shown that the reduced recombination events (followed by the increase in Rrec are also a result of increased grain size between the three HTLs, thus reduction in the grain boundary area. These charge accumulation properties of the three HTLs have resulted in an increase to the power conversion efficiency between the PEDOT:PSS (8.44%, Cu:NiOx (11.45%, and CuO (15.3%-based devices.

Charge-imbalance fluctuations in superconductors

International Nuclear Information System (INIS)

Lemberger, T.R.

1981-01-01

We calculate that the mean-square amplitude of the fluctuations of the condensate chemical potential μ/sub s/ due to charge-imbalance fluctuations in the limit Δ/k/sub B/T 2 > = 2(k/sub B/T) 2 /πdeltaΩN(0) in a volume Ω of superconductor. We relate these fluctuations via Nyquist's theorem to measured values of the contribution of self-injected charge imbalance to the dc resistance of SIN tunnel junctions. In this relation the dynamic charge-imbalance relaxation rate is 1/tau/sub E/, the electron-phonon scattering rate

Long-Acting Diclofenac Ester Prodrugs for Joint Injection

DEFF Research Database (Denmark)

Mertz, Nina; Larsen, Susan Weng; Kristensen, Jesper

2016-01-01

A prodrug approach for local and sustained diclofenac action after injection into joints based on ester prodrugs having a pH-dependent solubility is presented. Inherent ester prodrug properties influencing the duration of action include their pH-dependent solubility and charge state, as well...... as susceptibility to undergo esterase facilitated hydrolysis. In this study, physicochemical properties and pH rate profiles of 3 diclofenac ester prodrugs differing with respect to the spacer carbon chain length between the drug and the imidazole-based promoiety were determined and a rate equation for prodrug...... degradation in aqueous solution in the pH range 1-10 was derived. In the pH range 6-10, the prodrugs were subject to parallel degradation to yield diclofenac and an indolinone derivative. The prodrug degradation was found to be about 6-fold faster in 80% (vol/vol) human plasma as compared to 80% (vol...

Interplay of electronic and geometry shell effects in properties of neutral and charged Sr clusters

DEFF Research Database (Denmark)

Lyalin, Andrey; Solov'yov, Ilia; Solov'yov, Andrey V.

2007-01-01

that the size evolution of structural and electronic properties of strontium clusters is governed by an interplay of the electronic and geometry shell closures. Influence of the electronic shell effects on structural rearrangements can lead to violation of the icosahedral growth motif of strontium clusters......The optimized structure and electronic properties of neutral, singly, and doubly charged strontium clusters have been investigated using ab initio theoretical methods based on density-functional theory. We have systematically calculated the optimized geometries of neutral, singly, and doubly...... charged strontium clusters consisting of up to 14 atoms, average bonding distances, electronic shell closures, binding energies per atom, the gap between the highest occupied and the lowest unoccupied molecular orbitals, and spectra of the density of electronic states (DOS). It is demonstrated...

Impact of physical properties of mixture of diesel and biodiesel fuels on hydrodynamic characteristics of fuel injection system

Directory of Open Access Journals (Sweden)

Filipović Ivan M.

2014-01-01

Full Text Available One of the alternative fuels, originating from renewable sources, is biodiesel fuel, which is introduced in diesel engines without major construction modifications on the engine. Biodiesel fuel, by its physical and chemical properties, is different from diesel fuel. Therefore, it is expected that by the application of a biodiesel fuel, the characteristic parameters of the injection system will change. These parameters have a direct impact on the process of fuel dispersion into the engine cylinder, and mixing with the air, which results in an impact on the quality of the combustion process. Method of preparation of the air-fuel mixture and the quality of the combustion process directly affect the efficiency of the engine and the level of pollutant emissions in the exhaust gas, which today is the most important criterion for assessing the quality of the engine. The paper presents a detailed analysis of the influence of physical properties of a mixture of diesel and biodiesel fuels on the output characteristics of the fuel injection system. The following parameters are shown: injection pressure, injection rate, the beginning and duration of injection, transformation of potential into kinetic energy of fuel and increase of energy losses in fuel injection system of various mixtures of diesel and biodiesel fuels. For the analysis of the results a self-developed computer program was used to simulate the injection process in the system. Computational results are verified using the experiment, for a few mixtures of diesel and biodiesel fuels. This paper presents the verification results for diesel fuel and biodiesel fuel in particular.

Characterization of surface charge and mechanical properties of chitosan/alginate based biomaterials

International Nuclear Information System (INIS)

Verma, Devendra; Desai, Malav S.; Kulkarni, Namrata; Langrana, Noshir

2011-01-01

This study aims to examine mechanical properties and surface charge characteristics of chitosan/alginate-based films for biomedical applications. By varying the concentrations of chitosan and alginate, we have developed films with varying surface charge densities and mechanical characteristics. The surface charge densities of these films were determined by applying an analytical model on force curves derived from an atomic force microscope (AFM). The average surface charge densities of films containing 60% chitosan and 80% chitosan were found to be - 0.46 mC/m 2 and - 0.32 mC/m 2 , respectively. The surface charge density of 90% chitosan containing films was found to be neutral. The elastic moduli and the water content were found to be decreasing with increasing chitosan concentration. The films with 60%, 80% and 90% chitosan gained 93.5 ± 6.6%, 217.1 ± 22.1% and 396.8 ± 67.5% of their initial weight, respectively. Their elastic moduli were found to be 2.6 ± 0.14 MPa, 1.9 ± 0.27 MPa and 0.93 ± 0.12 MPa, respectively. The trend observed in the mechanical response of these films has been attributed to the combined effect of the concentration of polyelectrolyte complexes (PEC) and the amount of water absorbed. The Fourier transform infrared spectroscopy experiments indicate the presence of higher alginate on the surface of the films compared to the bulk in all films. The presence of higher alginate on surface is consistent with negative surface charge densities of these films, determined from AFM experiments. Highlights: → Chitosan/alginate based fibrous polyelectrolyte complex films were developed. → The average surface charge density of the films was determined using AFM. → Elastic modulus of the films increased with increase in PEC content. → FTIR analysis indicated higher alginate content on surface compared to bulk.

SIMULATIONS OF BOOSTER INJECTION EFFICIENCY FOR THE APS-UPGRADE

Energy Technology Data Exchange (ETDEWEB)

Calvey, J.; Borland, M.; Harkay, K.; Lindberg, R.; Yao, C.-Y.

2017-06-25

The APS-Upgrade will require the injector chain to provide high single bunch charge for swap-out injection. One possible limiting factor to achieving this is an observed reduction of injection efficiency into the booster synchrotron at high charge. We have simulated booster injection using the particle tracking code elegant, including a model for the booster impedance and beam loading in the RF cavities. The simulations point to two possible causes for reduced efficiency: energy oscillations leading to losses at high dispersion locations, and a vertical beam size blowup caused by ions in the Particle Accumulator Ring. We also show that the efficiency is much higher in an alternate booster lattice with smaller vertical beta function and zero dispersion in the straight sections.

Modelling the effect of nonplanarity on charge transport along conjugated polymer chains

International Nuclear Information System (INIS)

Correia, Helena M.G.; Ramos, Marta M.D.

2007-01-01

Conjugated polymers show interesting properties that make them appropriated for nanoelectronics. Several studies of poly(p-phenylene vinylene) (PPV) have suggested that each polymer chain consists of several planar segments, with conjugation length of nanoscale dimension, linked by twists or kinks. A pronounced twist between two planar segments in a PPV chain not only causes loss of main-chain conjugation but it may also alter electron and hole mobility along the chain, which has further implications for the percolation of charge through the polymer film. We used self-consistent quantum molecular dynamics calculations to provide information on the electric field needed to move the injected charges (either electrons or holes) along the planar segments of PPV and to cross the twist between two planar segments perpendicular to each other. Field-dependent charge mobility was also estimated for conjugated segments of various lengths. Our results suggest that electrons can cross the twist between adjacent planar segments for lower applied electric fields than holes if there is no more than one electronic charge (electron or hole) on the PPV chain, otherwise similar fields are needed

Surface characterisation and functionalisation of indium tin oxide anodes for improvement of charge injection in organic light emitting diodes

International Nuclear Information System (INIS)

Davenas, J.; Besbes, S.; Abderrahmen, A.; Jaffrezic, N.; Ben Ouada, H.

2008-01-01

Wettability studies have been performed to probe the surface properties of ITO substrates, aimed to be used as hole injecting electrode in OLEDs. The elimination of organic contaminants upon the cleaning treatment (ultrasonic bath in organic solvents) leads to an increase of the free energy of the ITO surface becoming hydrophilic. The surface energy components calculated from the Van Oss model show the appearance of a basic component upon the cleaning treatment. A thermal treatment at 100 deg. C for 3 h leads to a decrease of the surface free energy due to surface dehydration. These properties are attributed to the hydroxides formed at the ITO surface inducing improved adhesion at the ITO/polymer interface. The ITO surfaces have been functionalised with a chloroethylphosphonic acid mono-layer to increase their stability. The appearance of an acid-base component leads to a dipolar character of the ITO surface. The formation of a compact layer of a spin coated poly(phenylenevinylene) derivative induces the shielding of the ITO basic character. The weakening of the near infrared absorption associated to ITO free carriers confirms the formation of a dipole layer at the interface with the molecular layer in contact with ITO. Improved injection properties, shown by the current/voltage characteristics, result from the interface modifications

PLT and PDX perpendicular charge-exchange analyzers

International Nuclear Information System (INIS)

Mueller, D.; Hammett, G.W.; McCune, D.C.

1986-01-01

The perpendicular charge-exchange systems used on the poloidal divertor experiment and the Princeton large torus are comprised of ten-channel, mass-resolved, charge-exchange analyzers. Results from these systems indicate that instrumental effects can lead to erroneous temperature measurements during deuterium neutral beam injection or at low hydrogen concentrations

Spray-controlled combustionprocess with piezo injection; Strahlgefuehrtes Brennverfahren mit Piezo-Benzineinspritzung

Energy Technology Data Exchange (ETDEWEB)

Schaupp, U.; Altenschmidt, F.; Bertsch, D.; Laudenbach, N. [DaimlerChrysler AG, Stuttgart (Germany)

2007-07-01

The novel 2nd generation injection system of Mercedes-Benz have resulted in reduced fuel consumption and lower emissions while improving the engine performance. The piezo technology is a great technical advance. The characteristic field range in which stratified charge operation is possible has been extended since the first generation of injection systems. Lower fuel consumption is achieved not only in normal traffic but also when cruising on motorways at constant speed. The advantages are noticeable not only in the test cycle but also in real operation. The piezo injection valve was not available on the market and had to be constructed, including the 200 bar high-pressure fuel injection system. The stability of the injection system and the good mixing characteristics resulted in an optimally combustible mixture at the spark plug. Apart from stability in stratified charge operation, the possibility of multiple injection also has further advantages and potentials in terms of consumption and emissions. (orig.)

Microscopic studies of the fate of charges in organic semiconductors: Scanning Kelvin probe measurements of charge trapping, transport, and electric fields in p- and n-type devices

Science.gov (United States)

Smieska, Louisa Marion

Organic semiconductors could have wide-ranging applications in lightweight, efficient electronic circuits. However, several fundamental questions regarding organic electronic device behavior have not yet been fully addressed, including the nature of chemical charge traps, and robust models for injection and transport. Many studies focus on engineering devices through bulk transport measurements, but it is not always possible to infer the microscopic behavior leading to the observed measurements. In this thesis, we present scanning-probe microscope studies of organic semiconductor devices in an effort to connect local properties with local device behavior. First, we study the chemistry of charge trapping in pentacene transistors. Working devices are doped with known pentacene impurities and the extent of charge trap formation is mapped across the transistor channel. Trap-clearing spectroscopy is employed to measure an excitation of the pentacene charge trap species, enabling identification of the degradationrelated chemical trap in pentacene. Second, we examine transport and trapping in peryelene diimide (PDI) transistors. Local mobilities are extracted from surface potential profiles across a transistor channel, and charge injection kinetics are found to be highly sensitive to electrode cleanliness. Trap-clearing spectra generally resemble PDI absorption spectra, but one derivative yields evidence indicating variation in trap-clearing mechanisms for different surface chemistries. Trap formation rates are measured and found to be independent of surface chemistry, contradicting a proposed silanol trapping mechanism. Finally, we develop a variation of scanning Kelvin probe microscopy that enables measurement of electric fields through a position modulation. This method avoids taking a numeric derivative of potential, which can introduce high-frequency noise into the electric field signal. Preliminary data is presented, and the theoretical basis for electric field

Operational considerations for the PSB H- Injection System

CERN Document Server

Weterings, W; Borburgh, J; Carli, C; Fowler, T; Goddard, B

2010-01-01

For the LINAC4 project the PS Booster (PSB) injection system will be upgraded. The 160 MeV Hbeam will be distributed to the 4 superimposed PSB synchrotron rings and horizontally injected by means of an H- charge-exchange system. Operational considerations for the injection system are presented, including expected beam losses from unwanted field stripping of H- and excited H0 and foil scattering, possible injection failure cases and expected stripping foil lifetimes. Loading assumptions for the internal beam dumps are discussed together with estimates of doses on various components.

Charge preamplifier

International Nuclear Information System (INIS)

Chaminade, R.; Passerieux, J.P.

1961-01-01

We describe a charge preamplifier having the following properties: - large open loop gain giving both stable gain and large input charge transfer; - stable input grid current with aging and without any adjustment; - fairly fast rise; - nearly optimum noise performance; - industrial material. (authors)

Injectable calcium sulfate/mineralized collagen-based bone repair materials with regulable self-setting properties.

Science.gov (United States)

Chen, Zonggang; Liu, Huanye; Liu, Xi; Cui, Fu-Zhai

2011-12-15

An injectable and self-setting bone repair materials (nano-hydroxyapatite/collagen/calcium sulfate hemihydrate, nHAC/CSH) was developed in this study. The nano-hydroxyapatite/collagen (nHAC) composite, which is the mineralized fibril by self-assembly of nano-hydrocyapatite and collagen, has the same features as natural bone in both main hierarchical microstructure and composition. It is a bioactive osteoconductor due to its high level of biocompatibility and appropriate degradation rate. However, this material lacks handling characteristics because of its particle or solid-preformed block shape. Herein, calcium sulfate hemihydrate (CSH) was introduced into nHAC to prepare an injectable and self-setting in situ bone repair materials. The morphology of materials was observed using SEM. Most important and interesting of all, calcium sulfate dihydrate (CSD), which is not only the reactant of preparing CSH but also the final solidified product of CSH, was introduced into nHAC as setting accelerator to regulate self-setting properties of injectable nHAC/CSH composite, and thus the self-setting time of nHAC/CSH composite can be regulated from more than 100 min to about 30 min and even less than 20 min by adding various amount of setting accelerator. The compressive properties of bone graft substitute after final setting are similar to those of cancellous bone. CSD as an excellent setting accelerator has no significant effect on the mechanical property and degradability of bone repair materials. In vitro biocompatibility and in vivo histology studies demonstrated that the nHAC/CSH composite could provide more adequate stimulus for cell adhesion and proliferation, embodying favorable cell biocompatibility and a strong ability to accelerate bone formation. It can offer a satisfactory biological environment for growing new bone in the implants and for stimulating bone formation. Copyright © 2011 Wiley Periodicals, Inc.

Effect of thermal shock on mechanical properties of injection-molded thermoplastic denture base resins.

Science.gov (United States)

Takahashi, Yutaka; Hamanaka, Ippei; Shimizu, Hiroshi

2012-07-01

This study investigated the effect of thermal shock on the mechanical properties of injection-molded thermoplastic denture base resins. Four thermoplastic resins (two polyamides, one polyethylene terephthalate, one polycarbonate) and, as a control, a conventional heat-polymerized polymethyl methacrylate (PMMA), were tested. Specimens of each denture base material were fabricated according to ISO 1567 and were either thermocycled or not thermocycled (n = 10). The flexural strength at the proportional limit (FS-PL), the elastic modulus and the Charpy impact strength of the denture base materials were estimated. Thermocycling significantly decreased the FS-PL of one of the polyamides and the PMMA and it significantly increased the FS-PL of one of the polyamides. In addition, thermocycling significantly decreased the elastic modulus of one of the polyamides and significantly increased the elastic moduli of one of the polyamides, the polyethylene terephthalate, polycarbonate and PMMA. Thermocycling significantly decreased the impact strength of one of the polyamides and the polycarbonate. The mechanical properties of injection-molded thermoplastic denture base resins changed after themocycling.

Antibacterial properties of 2% lidocaine and reduced rate of endophthalmitis after intravitreal injection.

Science.gov (United States)

Tustin, Aaron; Kim, Stephen J; Chomsky, Amy; Hubbard, G Baker; Sheng, Jinsong

2014-05-01

To determine whether the application of subconjunctival 2% lidocaine/0.1% methylparaben for anesthesia may reduce rates of endophthalmitis after intravitreal (IVT) injection. We performed in vitro experiments to determine the antibacterial properties of 2% lidocaine/0.1% methylparaben (lidocaine) against causative organisms of endophthalmitis. Isolates of Staphylococcus aureus, Staphylococcus epidermidis, and Streptococcus viridans from patients with endophthalmitis were incubated with or without lidocaine. Aliquots (100 µL) were plated on Mueller-Hinton (S. aureus and S. epidermidis) or blood agar plates (S. viridans) at 0, 10, 30, 120, and 240 minutes, and colonies were counted after 24 hours. A retrospective review of 15,042 IVT injections was performed from January 2004 to February 2011 to determine the rate of endophthalmitis with or without application of subconjunctival lidocaine for anesthesia. Lidocaine demonstrated rapid bactericidal effects against all 3 organisms. After 10 minutes of exposure, there was approximately a 90% (P < 0.01), 95% (P < 0.001), and 92% (P < 0.001) reduction in colony forming units when compared with time 0 for S. aureus, S. epidermidis, and S. viridans, respectively. Complete elimination of colony forming units occurred at subsequent time points for each organism in contrast to logarithmic increase for control plates. There were a total of 0 cases of endophthalmitis of 6,853 IVT injections performed with subconjunctival lidocaine and 8 cases of endophthalmitis of 8,189 (0.1%) IVT injections performed with other methods of anesthesia (P = 0.03). Application of subconjunctival 2% lidocaine/0.1% methylparaben for anesthesia may reduce the incidence of endophthalmitis after IVT injection.

Space Charge Effects for the ERL Prototype Injector Line at Daresbury Laboratory

CERN Document Server

Muratori, Bruno; Owen, Hywel; de Loos, Marieke; van der Geer, Bas

2005-01-01

Daresbury Laboratory is currently building an Energy Recovery Linac Prototype (ERLP) that will operate at a beam energy of 35 MeV. In this paper we examine the space charge effects on the beam dynamics in the ERLP injector line. A Gaussian particle distribution is tracked with GPT (General Particle Tracer) through the injection line to the main linac to calculate the effect of 3Dspace charge in the dipoles. The nominal beam energy in the injection line is 8.3 MeV and the bunch charge 80 pC. The effects of space charge on the transverse and longitudinal emittance are studied for various electron beam parameter settings.

Charge transport problem

International Nuclear Information System (INIS)

Lee, E.P.

1977-01-01

In a recent report (UCID 17346, ''Relativistic Particle Beam in a Semi-Infinite Axially Symmetric conducting channel extending from a perfectly conducting plane,'' Dec. 13, 1976) Cooper and Neil demonstrate that the net charge transported by a beam pulse injected into a channel of finite conductivity equals the charge of the beam itself. The channel is taken to be infinite in the positive z direction, has finite radius and is terminated by a conducting ground plane at z =0. This result is not an obvious one, and it is restricted in its applicability by the special model assumed for the channel. It is the purpose to explain the result of Cooper and Neil in more qualitative terms and to make similar calculations using several other channel models. It must be emphasized that these calculations are not concerned with the fate of the transported charge after the pulse has stopped, but rather with how much charge leaves the ground plane assuming the pulse does not stop

Mechanical Properties Distribution within Polypropylene Injection Molded Samples: Effect of Mold Temperature under Uneven Thermal Conditions

Directory of Open Access Journals (Sweden)

Sara Liparoti

2017-11-01

Full Text Available The quality of the polymer parts produced by injection molding is strongly affected by the processing conditions. Uncontrolled deviations from the proper process parameters could significantly affect both internal structure and final material properties. In this work, to mimic an uneven temperature field, a strong asymmetric heating is applied during the production of injection-molded polypropylene samples. The morphology of the samples is characterized by optical and atomic force microscopy (AFM, whereas the distribution of mechanical modulus at different scales is obtained by Indentation and HarmoniX AFM tests. Results clearly show that the temperature differences between the two mold surfaces significantly affect the morphology distributions of the molded parts. This is due to both the uneven temperature field evolutions and to the asymmetric flow field. The final mechanical property distributions are determined by competition between the local molecular stretch and the local structuring achieved during solidification. The cooling rate changes affect internal structures in terms of relaxation/reorganization levels and give rise to an asymmetric distribution of mechanical properties.

Network access charges, vertical integration, and property rights structure - experiences from the German electricity markets

International Nuclear Information System (INIS)

Growitsch, C.; Wein, T.

2005-01-01

After the deregulation of the German electricity markets in 1998, the German government opted for a regulatory regime called negotiated third party access, which would be subject to ex-post control by the federal cartel office. Network access charges for new competitors are based on contractual arrangements between energy producers and industrial consumers. As the electricity networks are incontestable natural monopolies, the local and regional network operators are able to set (monopolistic) charges at their own discretion, restricted only by the possible interference of the federal cartel office (Bundeskartellamt). In this paper we analyze if there is evidence for varying charging behaviour depending on the supplier's economic independence (structure of property rights) or its level of vertical integration. For this purpose, we hypothesise that incorporated and vertically integrated suppliers set different charges than independent utility companies. Multivariate estimations show a relation between network access charges and the network operator's economic independence as well as level of vertical integration: on the low voltage level for an estimated annual consumption of 1700 kW/h, vertically integrated firms set-in accordance with our hypothesis-significantly lower access charges than vertically separated suppliers, whereas incorporated network operators charge significantly higher charges compared to independent suppliers. These results could not have been confirmed for other consumptions or voltage levels. (author)

Injection-controlled laser resonator

Science.gov (United States)

Chang, J.J.

1995-07-18

A new injection-controlled laser resonator incorporates self-filtering and self-imaging characteristics with an efficient injection scheme. A low-divergence laser signal is injected into the resonator, which enables the injection signal to be converted to the desired resonator modes before the main laser pulse starts. This injection technique and resonator design enable the laser cavity to improve the quality of the injection signal through self-filtering before the main laser pulse starts. The self-imaging property of the present resonator reduces the cavity induced diffraction effects and, in turn, improves the laser beam quality. 5 figs.

Space charge beam dynamics studies for a pulsed spallation source accelerator

Energy Technology Data Exchange (ETDEWEB)

Cho, Y.; Lessner, E.

1995-12-31

Feasibility studies for 2-GeV, 1-MW and 10-GeV, 5-MW rapid cycling synchrotrons (RCS) for spallation neutron sources have been completed. Both synchrotrons operate at a repetition rate of 30 Hz, and accelerate 1.04 {times} 10{sup 14} protons per pulse. The injection energy of the 2-GeV ring is 400 MeV, and the 10-GeV RCS accepts the beam from the 2-GeV machine. Work performed to-date includes calculation of the longitudinal space charge effects in the 400-MeV beam transfer line, and of both longitudinal and transverse space charge effects during the injection, capture and acceleration processes in the two rings. Results of space charge calculations in the rings led to proper choices of the working points and of rf voltage programs that prevents beam loss. Space charge effects in the 2-GeV synchrotron, in both transverse and longitudinal phase space, have major impact on the design due to the fact that the injection energy is 400 MeV. The design achieves the required performance while alleviating harmful effects due to space charge.

Status of the 160 MeV H- Injection into the CERN PSB

CERN Document Server

Weterings, W; Benedetto, E; Borburgh, J; Bracco, C; Carli, C; Goddard, B; Hanke, K; Mikulec, B; Newborough, A; Noulibos, R; Tan, J

2012-01-01

The 160 MeV H- beam from the LINAC4 will be injected into the 4 superimposed rings of the PS Booster (PSB) with a new H- charge-exchange injection system. This entails a massive upgrade of the injection region. The hardware requirements and constraints, the performance specifications and the design of the H- injection region are described.

A Method to Overcome Space Charge at Injection

International Nuclear Information System (INIS)

Ya. Derbenev

2005-01-01

The transverse space charge forces in a high current, low energy beam can be reduced by mean of a large increase of the beam's transverse sizes while maintaining the beam area in the 4D phase space. This can be achieved by transforming the beam area in phase space of each of two normal 2D transverse (either plane or circular) modes from a spot shape into a narrow ring of a large amplitude, but homogeneous in phase. Such a transformation results from the beam evolution in the island of a dipole resonance when the amplitude width of the island shrinks adiabatically. After stacking (by using stripping foils or cooling) the beam in such a state and accelerating to energies sufficiently high that the space charge becomes insignificant, the beam then can be returned back to a normal spot shape by applying the reverse transformation. An arrangement that can provide such beam gymnastics along a transport line after a linac and before a booster and/or in a ring with circulating beam will be described and numerical estimates will be presented. Other potential applications of the method will be briefly discussed

Impact of supercritical CO2 injection on petrophysical and rock mechanics properties of chalk: an experimental study on chalk from South Arne field, North Sea

DEFF Research Database (Denmark)

Alam, Mohammad Monzurul; Hjuler, Morten Leth; Christensen, Helle Foged

2011-01-01

Changes in chalk due to EOR by injecting supercritical CO2 (CO2-EOR) can ideally be predicted by applying geophysical methods designed from laboratory-determined petrophysical and rock mechanics properties. A series of petrophysical and rock mechanics tests were performed on Ekofisk Formation...... and Tor Formation chalk of the South Arne field to reveal the changes in petrophysical and rock mechanics properties of chalk due to the injection of CO2 at supercritical state. An increase in porosity and decrease in specific surface was observed due to injection of supercritical CO2. This indicates...... as indicated by NMR T2 relaxation time was observed. Rock mechanics testing indicates that in 30% porosity chalk from the South Arne field, injection of supercritical CO2 has no significant effect on shear strength and compaction properties, while there is probably a slight decrease in stiffness properties...

Charge transfer properties and photoelectrocatalytic activity of TiO{sub 2}/MWCNT hybrid

Energy Technology Data Exchange (ETDEWEB)

Jiang Liaochuan [Nano Science Research Center, School of Chemistry and Chemical Engineering, South China University of Technology, 381 Wushan Road, Guangzhou 510640 (China); Zhang Weide, E-mail: zhangwd@scut.edu.c [Nano Science Research Center, School of Chemistry and Chemical Engineering, South China University of Technology, 381 Wushan Road, Guangzhou 510640 (China)

2010-12-15

The vertically aligned multiwalled carbon nanotube (MWCNT) arrays on tantalum foils were successfully coated with TiO{sub 2} nanoparticles by a hydrothermal process. The prepared TiO{sub 2}/MWCNT hybrid was characterized by scanning electron microscopy and transmission electron microscopy. The charge transfer properties and photocatalytic degradation of rhodamine B with and without bias potential under UV irradiation were investigated. The MWCNTs promoted the separation of photoinduced carriers in the TiO{sub 2}, thus enhanced photocatalytic activity. Applying bias potential on the photoanode further enhanced its catalytic activity. The efficient charge transportation and high photoelectrocatalytic activity towards degradation of rhodamine B made this hybrid material promising for photocatalyst and for the development of photoelectrical devices.

Dielectric sample with two-layer charge distribution for space charge calibration purposes

DEFF Research Database (Denmark)

Holbøll, Joachim; Henriksen, Mogens; Rasmussen, C.

2002-01-01

In the present paper is described a dielectric test sample with two very narrow concentrations of bulk charges, achieved by two internal electrodes not affecting the acoustical properties of the sample, a fact important for optimal application of most space charge measuring systems. Space charge...

The charge collection in single side silicon microstrip detectors

CERN Document Server

Eremin, V V; Roe, S; Ruggiero, G; Weilhammer, Peter

2003-01-01

The transient current technique has been used to investigate signal formation in unirradiated silicon microstrip detectors, which are similar in geometry to those developed for the ATLAS experiment at LHC. Nanosecond pulsed infrared and red lasers were used to induce the signals under study. Two peculiarities in the detector performance were observed: an unexpectedly slow rise to the signal induced in a given strip when signals are injected opposite to the strip, and a long duration of the induced signal in comparison with the calculated drift time of charge carriers through the detector thickness - with a significant fraction of the charge being induced after charge carrier arrival. These major effects and details of the detector response for different positions of charge injection are discussed in the context of Ramo's theorem and compared with predictions arising from the more commonly studied phenomenon of signal formation in planar pad detectors.

Dynamics of morphofunctional erythrocyte properties during intravenous glucose injection in patients with coronary heart disease

Science.gov (United States)

Malinova, Lidia I.; Simonenko, Georgy V.; Denisova, Tatyana P.; Tuchin, Valery V.

2007-02-01

Dynamics of glucose concentration in human organism is an important diagnostic characteristic for it's parameters correlate significantly with the severity of metabolic, vessel and perfusion disorders. 36 patients with stable angina pectoris of II and III functional classes were involved in this study. All of them were men in age range of 45-59 years old. 7 patients hospitalized with acute myocardial infarction (aged from 49 to 59 years old) form the group of compare. Control group (n = 5) was of practically healthy men in comparable age. To all patients intravenous glucose solution (40%) in standard loading dose was injected. Capillary and vein blood samples were withdrawn before, and 5, 60, 120, 180 and 240 minutes after glucose load. At these time points blood pressure and glucose concentration were measured. In prepared blood smears shape, deformability and sizes of erythrocytes, quantity and degree of shear stress resistant erythrocyte aggregates were studied. Received data were approximated by polynomial of high degree to receive concentration function of studied parameters, which first derivative elucidate velocity characteristics of morphofunctional erythrocyte properties during intravenous glucose injection in patients with coronary heart disease and practically healthy persons. Received data show principle differences in dynamics of morphofunctional erythrocyte properties during intravenous glucose injection in patients with coronary heart disease as a possible mechanism of coronary blood flow destabilization.

Local charge transport properties of hydrazine reduced monolayer graphene oxide sheets prepared under pressure condition

DEFF Research Database (Denmark)

Ryuzaki, Sou; Meyer, Jakob Abild Stengaard; Petersen, Søren Vermehren

2014-01-01

Charge transport properties of chemically reduced graphene oxide (RGO) sheets prepared by treatment with hydrazine were examined using conductive atomic force microscopy. The current-voltage (I-V) characteristics of monolayer RGO sheets prepared under atmospheric pressure followed an exponentially...

Charge carrier dynamics in thin film solar cells

Energy Technology Data Exchange (ETDEWEB)

Strothkaemper, Christian

2013-06-24

This work investigates the charge carrier dynamics in three different technological approaches within the class of thin film solar cells: radial heterojunctions, the dye solar cell, and microcrystalline CuInSe{sub 2}, focusing on charge transport and separation at the electrode, and the relaxation of photogenerated charge carriers due to recombination and energy dissipation to the phonon system. This work relies mostly on optical-pump terahertz-probe (OPTP) spectroscopy, followed by transient absorption (TA) and two-photon photoemission (2PPE). The charge separation in ZnO-electrode/In{sub 2}S{sub 3}-absorber core/shell nanorods, which represent a model system of a radial heterojunction, is analyzed by OPTP. It is concluded, that the dynamics in the absorber are determined by multiple trapping, which leads to a dispersive charge transport to the electrode that lasts over hundreds of picoseconds. The high trap density on the order of 10{sup 19}/cm{sup 3} is detrimental for the injection yield, which exhibits a decrease with increasing shell thickness. The heterogeneous electron transfer from a series of model dyes into ZnO proceeds on a time-scale of 200 fs. However, the photoconductivity builds up just on a 2-10 ps timescale, and 2PPE reveals that injected electrons are meanwhile localized spatially and energetically at the interface. It is concluded that the injection proceeds through adsorbate induced interface states. This is an important result because the back reaction from long lived interface states can be expected to be much faster than from bulk states. While the charge transport in stoichiometric CuInSe{sub 2} thin films is indicative of free charge carriers, CuInSe{sub 2} with a solar cell grade composition (Cu-poor) exhibits signs of carrier localization. This detrimental effect is attributed to a high density of charged defects and a high degree of compensation, which together create a spatially fluctuating potential that inhibits charge transport. On

The effects of interfacial recombination and injection barrier on the electrical characteristics of perovskite solar cells

Directory of Open Access Journals (Sweden)

Lin Xing Shi

2018-02-01

Full Text Available Charge carrier recombination in the perovskite solar cells (PSCs has a deep influence on the electrical performance, such as open circuit voltage, short circuit current, fill factor and ultimately power conversion efficiency. The impacts of injection barrier, recombination channels, doping properties of carrier transport layers and light intensity on the performance of PSCs are theoretically investigated by drift-diffusion model in this work. The results indicate that due to the injection barrier at the interfaces of perovskite and carrier transport layer, the accumulated carriers modify the electric field distribution throughout the PSCs. Thus, a zero electric field is generated at a specific applied voltage, with greatly increases the interfacial recombination, resulting in a local kink of current density-voltage (J-V curve. This work provides an effective strategy to improve the efficiency of PSCs by pertinently reducing both the injection barrier and interfacial recombination.

Varying the charge of small cations in liquid water: Structural, transport, and thermodynamical properties

Science.gov (United States)

Martelli, Fausto; Vuilleumier, Rodolphe; Simonin, Jean-Pierre; Spezia, Riccardo

2012-10-01

In this work, we show how increasing the charge of small cations affects the structural, thermodynamical, and dynamical properties of these ions in liquid water. We have studied the case of lanthanoid and actinoid ions, for which we have recently developed accurate polarizable force fields, and the ionic radius is in the 0.995-1.250 Å range, and explored the valency range from 0 to 4+. We found that the ion charge strongly structures the neighboring water molecules and that, in this range of charges, the hydration enthalpies exhibit a quadratic dependence with respect to the charge, in line with the Born model. The diffusion process follows two main regimes: a hydrodynamical regime for neutral or low charges, and a dielectric friction regime for high charges in which the contraction of the ionic radius along the series of elements causes a decrease of the diffusion coefficient. This latter behavior can be qualitatively described by theoretical models, such as the Zwanzig and the solvated ion models. However, these models need be modified in order to obtain agreement with the observed behavior in the full charge range. We have thus modified the solvated ion model by introducing a dependence of the bare ion radius as a function of the ionic charge. Besides agreement between theory and simulation this modification allows one to obtain an empirical unified model. Thus, by analyzing the contributions to the drag coefficient from the viscous and the dielectric terms, we are able to explain the transition from a regime in which the effect of viscosity dominates to one in which dielectric friction governs the motion of ions with radii of ca. 1 Å.

Properties of the chromatin assembled on DNA injected into Xenopus oocytes and eggs

International Nuclear Information System (INIS)

Gargiulo, G.; Wasserman, W.; Worcel, A.

1983-01-01

The onset of DNA synthesis occurs between 10 and 30 minutes after activation of the egg and thus the transition from nuclease-sensitive to nuclease-resistant supercoils may take place on the newly replicated DNA. To test this possibility, the nonradioactive circular 5-kb DNA carrying the Drosophila histone gene repeat and [α -32 P]dCTP were coinjected into fertilized eggs. Such protocol labels both the injected, replicated heterologous DNA and the replicated endogenous, maternal Xenopus DNA. The labeled, presumably replicated, supercoiled DNA is resistant to micrococcal nuclease as expected. The endogenous, high-molecular-weight Xenopus DNA is degraded to 180-bp nucleosomal DNA. Thus, the nuclease resistance is not a general property of chromatin during the cleavage stage of the Xenopus embryo but is a peculiar feature of the injected DNA. 42 references, 5 figures

Mechanical properties of the weld line defect in micro injection molding for various nano filled polypropylene composites

International Nuclear Information System (INIS)

Xie Lei; Ziegmann, Gerhard

2011-01-01

Research highlights: → PP/CNFs and PP/TiO 2 composites with relative high loading fractions (10, 20, 30 and 35 wt%) were fabricated by inner melt mixing process. Micro tensile test samples were formed by injection molding combined with variotherm process for all composites. → The morphological properties of all nano composites were characterized by WXRD, whose results imply the adding nano fillers did not change the crystal form of PP, but the crystallites size and distance between lattices of crystals were changed with various nano fillers and loading fractions. → DSC analysis show that due to the nucleating function of nano fillers, the peak temperature of crystallization was increased and the peak temperature of crystallization melting was decreased by adding the nanofillers. → The flow ability of nano composites was tested by high pressure single capillary rheometer and the results demonstrate that nano fillers increased the viscosity of PP matrix. → Based on these significant information and analysis foundation of the nano filled composites, the micro weld line samples were formed by injection molding process and characterized by tensile test method. From the achieved results, it can be found that in general, for functional nano filled polymer composites, the mechanical property of micro weld lines were obviously influenced by nano fillers' shape and loading fractions. → The E modulus of micro weld line was increased due to loading CNFs in PP matrix, while the elongation of the micro tensile samples with weld line is considerably decreased comparing with those of unfilled PP samples. The detrimental tensile strength of micro weld lines were observed when CNFs contents increasing, except for at a 10 wt%. → For TiO 2 nano particles filled PP, due to the poor dispersion of nano particles, at low loading fraction of 10 wt%, the E modulus and tensile strength of micro weld lines were decreased by filling nano particles, but when the loading fraction

Mechanical design of injection line for VEC

International Nuclear Information System (INIS)

Nandi, C.; Bandopadhyay, D.K.; Pal, G.; Sharma, R.N.; Mallik, C.; Chaudhuri, J.; Bhandari, R.K.

2003-01-01

A 14.5 GHz ECR ion source along with its analyzing section was earlier installed at VECC for injecting multiply charged gaseous and metallic ions into the existing K 130 cyclotron. The injection line from this ECR ion source was connected to the vertical section of the existing injection line for integrating it with the K 130 cyclotron. The injection line comprises two solenoid magnets, a steering magnet, and a bending magnet. In between the solenoid magnets a length about 1.5 metres has been provided for future atomic physics experimental applications. Two gate valves are used to isolate this area. For beam diagnostics, two Faraday cups, designed and fabricated in this centre, have been installed

An investigation of flow properties of metal matrix composites suspensions for injection molding

International Nuclear Information System (INIS)

Ahmad, F.; Bevis, M.J.

1997-01-01

Flow properties of metal matrix composites suspensions have significant effects on the fibre orientation during mould filling. The results presented in this paper relate to the flow properties of aluminium powder and glass fibres compounded into a sacrificial thermoplastics binder. For this purpose, a range of aluminium compounds and aluminium composite suspensions were investigated over a wide shear rate range expected to occur during injection mould process. Aluminium composites wee prepared by substituting glass fibres for aluminium in aluminium compound. Aluminium composite containing a maximum critical volume fraction of fibres which did not exhibit an increase n viscosity was determined. The effect of temperature on the flow behaviour of aluminium composite was also investigated. (author)

Non-Liouvillean ion injection via resonantly enhanced two-photon ionization

Directory of Open Access Journals (Sweden)

B. A. Knyazev

2004-03-01

Full Text Available The charge-exchange method is now one of the main techniques for ion injection into accelerators and storage rings. The disadvantages of conventional methods, based on the atom or ion stripping in a material target, are emittance growth, energy straggling, and production of ions in many charge states. Recently suggested stripping methods based on direct photoionization require employment of hard-UV lasers, which still do not exist and must obviously be very bulky and expensive. An alternative method, suggested for injection of proton beams, employs excitation of the atom to 3p intermediate state with subsequent Lorentz ionization in a magnetic field gradient. This technique applies rigid requirements to laser characteristic and is not free of growing of the beam divergence. In this paper a variant of the stripping technique based on the resonantly enhanced two-photon ionization (RETPI is considered. The technique allows ionization of singly charged ions of the elements from helium to bismuth. A variant of the technique can be used for proton injection. RETPI can be applied for both ion injection and stacking, as well as for diagnostics of ion beam characteristics on the orbit. Stripping efficiency can be about 100% for the singly charged ions having the singlet ground state and decreases for the other ions. Special methods for “cleaning” unwanted atomic states in such ions, that can provide high stripping efficiency, are discussed. Excimer lasers with very moderate parameters can be employed for implementation of this technique for almost all elements. Numerical examples show that for most of the singly charged ions and for hydrogen atom necessary laser-beam energy density is merely 0.5–8  J/cm^{2} for a 1 m interaction region, and is 10 times higher for several light ions.

Charge collection in the Silicon Drift Detectors of the ALICE experiment

CERN Document Server

Alessandro, B; Batigne, G; Beolé, S; Biolcati, E; Cerello, P; Coli, S; Corrales Morales, Y; Crescio, E; De Remigis, P; Falchieri, D; Giraudo, G; Giubellino, P; Lea, R; Marzari Chiesa, A; Masera, M; Mazza, G; Ortona, G; Prino, F; Ramello, L; Rashevsky, A; Riccati, L; Rivetti, A; Senyukov, S; Siciliano, M; Sitta, M; Subieta, M; Toscano, L; Tosello, F

2010-01-01

A detailed study of charge collection efficiency has been performed on the Silicon Drift Detectors (SDD) of the ALICE experiment. Three different methods to study the collected charge as a function of the drift time have been implemented. The first approach consists in measuring the charge at different injection distances moving an infrared laser by means of micrometric step motors. The second method is based on the measurement of the charge injected by the laser at fixed drift distance and varying the drift field, thus changing the drift time. In the last method, the measurement of the charge deposited by atmospheric muons is used to study the charge collection efficiency as a function of the drift time. The three methods gave consistent results and indicated that no charge loss during the drift is observed for the sensor types used in 99% of the SDD modules mounted on the ALICE Inner Tracking System. The atmospheric muons have also been used to test the effect of the zero-suppression applied to reduce the d...

An EBIS for charge state breeding in the SPES project

Indian Academy of Sciences (India)

The 'charge state breeder', BRIC (breeding ion charge) is in construction at the INFN section of Bari (Italy). It is based on EBIS scheme and it is designed to accept radioactive ion beam (RIB) with charge state +1 in a slow injection mode. This experiment can be considered as a first step towards the design and construction ...

Modeling charge transport properties of cyano-substituted PPV

International Nuclear Information System (INIS)

Correia, Helena M.G.; Ramos, Marta M.D.

2003-01-01

In recent years, poly (p-phenylenevinylene) (PPV) and its derivatives have attracted much interest due to their applications in light-emitting diodes (LEDs). One of the issues that determine device performance is the transport of charge carriers along the polymer strands. For that reason, we investigate the influence of cyano substitution on geometry and electronic behaviour of PPV chains using self-consistent quantum molecular dynamics simulations. Our results suggest that substitution by cyano groups induce distortion in the PPV chains and a charge rearrangement among the polymer atoms. Specifically addressed is the issue concerning estimates of charge (electron and hole) mobility by computer experiments. Significant differences have been found both in the strength of the electric field needed to move positive and negative charge carriers along the polymer chain as well as in charge mobility

Transport properties of triarylamine based dendrimers studied by space charge limited current transients

Science.gov (United States)

Szymanski, Marek Z.; Kulszewicz-Bajer, Irena; Faure-Vincent, Jérôme; Djurado, David

2012-08-01

We have studied hole transport in triarylamine based dendrimer using space-charge-limited current transient technique. A mobility of 8 × 10-6 cm2/(V s) and a characteristic detrapping time of about 100 ms have been obtained. We found that quasi-ohmic contact is formed with gold. The obtained mobility differs from the apparent one given by the analysis of stationary current-voltage characteristics because of a limited contact efficiency. The comparison between transients obtained from fresh and aged samples reveals no change in mobility with aging. The deterioration of electrical properties is exclusively caused by trap formation and accumulation of ionic conducting impurities. Finally, repeated transient measurements have been applied to analyze the dynamics of charge trapping process.

Dynamic space charge behaviour in polymeric DC cables

DEFF Research Database (Denmark)

Rasmussen, Claus Nygaard; Holbøll, Joachim; Henriksen, Mogens

2002-01-01

The use of extruded insulation for DC cables involves a risk of local electric field enhancement, caused by a space charge build-up within the dielectric. In this work, the theory of charge generation and transport in polymers is applied in a numerical computer model in order to predict...... the formation and transport of space charges in a polymeric dielectric. The model incorporates the processes of field assisted electron-hole pair generation from impurity atoms, trapping and charge injection at the electrodes. Its aim has been to study the field- and temperature dependent dynamic behaviour...

Modulated charge injection in p-type dye-sensitized solar cells using fluorene-based light absorbers.

Science.gov (United States)

Liu, Zonghao; Xiong, Dehua; Xu, Xiaobao; Arooj, Qudsia; Wang, Huan; Yin, Liyuan; Li, Wenhui; Wu, Huaizhi; Zhao, Zhixin; Chen, Wei; Wang, Mingkui; Wang, Feng; Cheng, Yi-Bing; He, Hongshan

2014-03-12

In this study, new pull-push arylamine-fluorene based organic dyes zzx-op1, zzx-op2, and zzx-op3 have been designed and synthesized for p-type dye-sensitized solar cells (p-DSCs). In zzx-op1, a di(p-carboxyphenyl)amine (DCPA) was used as an electron donor, a perylenemonoimide (PMID) as an electron acceptor, and a fluorene (FLU) unit with two aliphatic hexyl chains as a π-conjugated linker. In zzx-op2 and zzx-op3, a 3,4-ethylenedioxythiophene (EDOT) and a thiophene were inserted consecutively between PMID and FLU to tune the energy levels of the frontier molecular orbitals of the dyes. The structural modification broadened the spectral coverage from an onset of 700 nm for zzx-op1 to 750 nm for zzx-op3. The electron-rich EDOT and thiophene lifted up the HOMO (highest occupied molecular orbital) levels of zzx-op2 and zzx-op3, making their potential more negative than zzx-op1. When three dyes were employed in p-type DSCs with I(-)/I3(-) as a redox couple and NiO nanoparticles as hole materials, zzx-op1 exhibited impressive energy conversion efficiency of 0.184% with the open-circuit voltage (VOC) of 112 mV and the short-circuit current density (JSC) of 4.36 mA cm(-2) under AM 1.5G condition. Density functional theory calculations, transient photovoltage decay measurements, and electrochemical impedance spectroscopic studies revealed that zzx-op1 sensitized solar cell exhibited much higher charge injection efficiency (90.3%) than zzx-op2 (53.9%) and zzx-op3 (39.0%), indicating a trade-off between spectral broadening and electron injection driving force in p-type DSCs.

Local mechanical properties of LFT injection molded parts: Numerical simulations versus experiments

Science.gov (United States)

Desplentere, F.; Soete, K.; Bonte, H.; Debrabandere, E.

2014-05-01

In predictive engineering for polymer processes, the proper prediction of material microstructure from known processing conditions and constituent material properties is a critical step forward properly predicting bulk properties in the finished composite. Operating within the context of long-fiber thermoplastics (LFT, length Autodesk Simulation Moldflow Insight 2014 software has been used. In this software, a fiber breakage algorithm for the polymer flow inside the mold is available. Using well known micro mechanic formulas allow to combine the local fiber length with the local orientation into local mechanical properties. Different experiments were performed using a commercially available glass fiber filled compound to compare the measured data with the numerical simulation results. In this investigation, tensile tests and 3 point bending tests are considered. To characterize the fiber length distribution of the polymer melt entering the mold (necessary for the numerical simulations), air shots were performed. For those air shots, similar homogenization conditions were used as during the injection molding tests. The fiber length distribution is characterized using automated optical method on samples for which the matrix material is burned away. Using the appropriate settings for the different experiments, good predictions of the local mechanical properties are obtained.

Internal combustion engine using premixed combustion of stratified charges

Science.gov (United States)

Marriott, Craig D [Rochester Hills, MI; Reitz, Rolf D [Madison, WI

2003-12-30

During a combustion cycle, a first stoichiometrically lean fuel charge is injected well prior to top dead center, preferably during the intake stroke. This first fuel charge is substantially mixed with the combustion chamber air during subsequent motion of the piston towards top dead center. A subsequent fuel charge is then injected prior to top dead center to create a stratified, locally richer mixture (but still leaner than stoichiometric) within the combustion chamber. The locally rich region within the combustion chamber has sufficient fuel density to autoignite, and its self-ignition serves to activate ignition for the lean mixture existing within the remainder of the combustion chamber. Because the mixture within the combustion chamber is overall premixed and relatively lean, NO.sub.x and soot production are significantly diminished.

Adsorption and Aqueous Lubricating Properties of Charged and Neutral Amphiphilic Diblock Copolymers at a Compliant, Hydrophobic Interface

DEFF Research Database (Denmark)

Røn, Troels; Javakhishvili, Irakli; Jankova Atanasova, Katja

2013-01-01

We have investigated the adsorption and lubricating properties of neutral and charged amphiphilic diblock copolymers at a hydrophobic polydimethylsiloxane (PDMS) interface in an aqueous environment. The diblock copolymers consist of a hydrophilic block of either neutral poly(ethylene glycol) (PEG......) or negatively charged poly(acrylic acid) (PAA) and of a hydrophobic block of polystyrene (PS) or poly(2-methoxyethyl acrylate) (PMEA), thus generating PEG-b-X or PAA-b-X, where X block is either PS or PMEA. The molecular weight ratios were roughly 1:1 with each block ca. 5 kDa. Comparing the neutral PEG...... effective adsorption only when PMEA was employed as the anchoring block. For PAA-b-PS, the poor adsorption properties are chiefly attributed to micellization due to the high interfacial tension between the PS core and water. The poor lubricating properties of PAA-b-PS diblock copolymer for a PDMS...

Fast electron beam charge injection and switching in dielectrics

Energy Technology Data Exchange (ETDEWEB)

Fitting, Hans-Joachim; Schreiber, Erik [Institute of Physics, University of Rostock, Universitaetsplatz 3, 18051 Rostock (Germany); Touzin, Matthieu [Laboratoire de Structure et Proprietes de l' Etat Solide, UMR CNRS 8008, Universite de Lille 1, 59655 Villeneuve d' Ascq (France)

2011-04-15

Basic investigations of secondary electrons (SE) relaxation and attenuation are made by means of Monte Carlo simulations using ballistic electron scattering and interactions with optical and acoustic phonons as well as impact ionization of valence band electrons. Then the electron beam induced selfconsistent charge transport and secondary electron emission in insulators are described by means of an electron-hole flight-drift model (FDM). Ballistic secondary electrons and holes, their attenuation and drift, as well as their recombination, trapping, and field- and temperature-dependent Poole-Frenkel detrapping are included. Whereas the initial switching-on of the secondary electron emission proceeds over milli-seconds due to long-lasting selfconsistent charging, the switching-off process occurs much faster, even over femto-seconds. Thus a rapid electron beam switching becomes possible with formation of ultra-short electron beam pulses offering an application in stroboscopic electron microscopy and spectroscopy. (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Behavior of pellet injected Li ions into heliotron E plasmas

International Nuclear Information System (INIS)

Kondo, K.; Christou, C.; Ida, K.

1996-07-01

Li pellet injection has provided a complex plasma with a large fraction of Li ions, which is characterized by intense emissions from Li I and III. The spatial profiles of the fully ionized Li 3+ ions are measured by charge exchange recombination spectroscopy with a resolution of 13 mm, and the local decay time of the injected Li ion has been estimated. The spectral profile of the charge exchange recombination line of Li 2+ from n=5 to n=4 shows a complicated structure, which depends of Li 3+ density. The effects on other intrinsic impurities and recycled Li are also discussed. (author)

Charge balancing fill rate monitor

International Nuclear Information System (INIS)

Rothman, J.L.; Blum, E.B.

1995-01-01

A fill rate monitor has been developed for the NSLS storage rings to allow machine tuning over a very large dynamic range of beam current. Synchrotron light, focused on a photodiode, produces a signal proportional to the beam current. A charge balancing circuit processes the diode current, creating an output signal proportional to the current injected into the ring. The unit operates linearly over a dynamic range of 120 dB and can resolve pulses of injected beam as small as 1 μA

Analysis of Conduction and Charging Mechanisms in Atomic Layer Deposited Multilayered HfO2/Al2O3 Stacks for Use in Charge Trapping Flash Memories

Directory of Open Access Journals (Sweden)

Nenad Novkovski

2018-01-01

Full Text Available Method for characterization of electrical and trapping properties of multilayered high permittivity stacks for use in charge trapping flash memories is proposed. Application of the method to the case of multilayered HfO2/Al2O3 stacks is presented. By applying our previously developed comprehensive model for MOS structures containing high-κ dielectrics on the J-V characteristics measured in the voltage range without marked degradation and charge trapping (from −3 V to +3 V, several parameters of the structure connected to the interfacial layer and the conduction mechanisms have been extracted. We found that the above analysis gives precise information on the main characteristics and the quality of the injection layer. C-V characteristics of stressed (with write and erase pulses structures recorded in a limited range of voltages between −1 V and +1 V (where neither significant charge trapping nor visible degradation of the structures is expected to occur were used in order to provide measures of the effect of stresses with no influence of the measurement process. Both trapped charge and the distribution of interface states have been determined using modified Terman method for fresh structures and for structures stressed with write and erase cycles. The proposed method allows determination of charge trapping and interface state with high resolution, promising a precise characterization of multilayered high permittivity stacks for use in charge trapping flash memories.

Physics of the current injection process during localized helicity injection

Science.gov (United States)

Hinson, Edward Thomas

An impedance model has been developed for the arc-plasma cathode electron current source used in localized helicity injection tokamak startup. According to this model, a potential double layer (DL) is established between the high-density arc plasma (narc ˜ 1021 m-3) in the electron source, and the less-dense external tokamak edge plasma (nedge ˜ 10 18 m-3) into which current is injected. The DL launches an electron beam at the applied voltage with cross-sectional area close to that of the source aperture: Ainj ≈ 2 cm 2. The injected current, Iinj, increases with applied voltage, Vinj, according to the standard DL scaling, Iinj ˜ V(3/2/ inj), until the more restrictive of two limits to beam density nb arises, producing Iinj ˜ V(1/2/inj), a scaling with beam drift velocity. For low external tokamak edge density nedge, space-charge neutralization of the intense electron beam restricts the injected beam density to nb ˜ nedge. At high Jinj and sufficient edge density, the injected current is limited by expansion of the DL sheath, which leads to nb ˜ narc. Measurements of narc, Iinj , nedge, Vinj, support these predicted scalings, and suggest narc as a viable control actuator for the source impedance. Magnetic probe signals ≈ 300 degrees toroidally from the injection location are consistent with expectations for a gyrating, coherent electron beam with a compact areal cross-section. Technological development of the source has allowed an extension of the favorable Iinj ˜ V(1/2/inj) to higher power without electrical breakdown.

Emission Characteristics for a Homogeneous Charged Compression Ignition Diesel Engine with Exhaust Gas Recirculation Using Split Injection Methodology

Directory of Open Access Journals (Sweden)

Changhee Lee

2017-12-01

Full Text Available Due to the serious issues caused by air pollution and global warming, emission regulations are becoming stricter. New technologies that reduce NOx and PM emissions are needed. To cope with these social exhaust gas regulation demands, many advanced countries are striving to develop eco-friendly vehicles in order to respond to stricter emissions regulations. The homogeneous charged compression ignition engine (HCCI incorporates a multi-stage combustion engine with multiple combustion modes, catalyst, direct fuel injection and partial mixing combustion. In this study, the HCCI combustion was applied to analyze and review the results of engines applying HCCI combustion without altering the conventional engine specifications. The optimization of exhaust gas recirculation (EGR and compression ratio changes provides an optimal fuel economy. In this study, potential for optimum economy within the range of IMEP 0.8 MPa has been evaluated.

AN EXPERIMENTAL NOX REDUCTION POTENTIAL INVESTIGATION OF THE PARTIAL HCCI APPLICATION, ON A HIGH PRESSURE FUEL INJECTION EQUIPPED DIESEL ENGINE BY IMPLEMENTING FUMIGATION OF GASOLINE PORT INJECTION

OpenAIRE

ERGENÇ, Alp Tekin; YÜKSEK, Levent; ÖZENER, Orkun; IŞIN, Övün

2016-01-01

This work investigates the effects of partial HCCI (Homogeneous charge compression ignition) application on today's modern diesel engine tail pipe NOx emissions. Gasoline fumigation is supplied via a port fuel injection system located in the intake port of DI(Direct injection) diesel engine to maintain partial HCCI conditions and also diesel fuel injected directly into the combustion chamber before TDC(Top dead center). A single cylinder direct injection diesel research engine equipped w...

Fast ion behavior during neutral beam injection in ATF

International Nuclear Information System (INIS)

Wade, M.R.; Thomas, C.E.; Colchin, R.J.; Rome, J.A.; England, A.C.; Fowler, R.H.; Aceto, S.C.

1993-01-01

In stellarators, single-particle confinement properties can be more complex than in their tokamak counterparts. Fast-ion behavior in tokamaks has been well characterized through an abundance of measurements on various devices and in general has been shown to be consistent with classical slowing-down theory, although anomalous ion behavior has been observed during intense beam injection in ISX-B, during fishbone instabilities in PDX, and in experiments on TFR. In contrast, fast ion behavior in stellarators is not as wel established experimentally with the primary experiments to date focusing o near-perpendicular or perpendicular neutral beam injection (NBI) on the Wendelstein 7-A stellarator (91 and Heliotron-E. This paper addresses fast-ion confinement properties in a large-aspect-ratio, moderate-shear stellarator, the Advanced Toroidal Facility, during tangential NBI. The primary data used in this study are the experimentally measured energy spectra of charge-exchange neutrals escaping from the plasma, using a two-dimensional scanning neutral particle analyzer. This diagnostic method is well established, having been used on several devices since the early 1970's. Various aspects of fast-ion behavior are investigated by comparing these data with computed theoretical spectra based on energeticion distributions derived from the fastion Fokker-Planck equation. Ion orbits are studied by computer orbit following, by the computation of J* surfaces, and by Monte Carlo calculations

Elastin Based Cell-laden Injectable Hydrogels with Tunable Gelation, Mechanical and Biodegradation Properties

Science.gov (United States)

Fathi, Ali; Mithieux, Suzanne M.; Wei, Hua; Chrzanowski, Wojciech; Valtchev, Peter; Weiss, Anthony S.; Dehghani, Fariba

2015-01-01

Injectable hydrogels made from extracellular matrix proteins such as elastin show great promise for various biomedical applications. Use of cytotoxic reagents, fixed gelling behavior, and lack of mechanical strength in these hydrogels are the main associated drawbacks. The aim of this study was to develop highly cytocompatible and injectable elastin-based hydrogels with alterable gelation characteristics, favorable mechanical properties and structural stability for load bearing applications. A thermoresponsive copolymer, poly(N-isopropylacrylamide-co-polylactide-2-hydroxyethyl methacrylate-co-oligo(ethylene glycol)monomethyl ether methacrylate, was functionalized with succinimide ester groups by incorporating N-acryloxysuccinimide monomer. These ester groups were exploited to covalently bond this polymer, denoted as PNPHO, to different proteins with primary amine groups such as α-elastin in aqueous media. The incorporation of elastin through covalent bond formation with PNPHO promotes the structural stability, mechanical properties and live cell proliferation within the structure of hydrogels. Our results demonstrated that elastin-co-PNPHO solutions were injectable through fine gauge needles and converted to hydrogels in situ at 37 °C in the absence of any crosslinking reagent. By altering PNPHO content, the gelling time of these hydrogels can be finely tuned within the range of 2 to 15 min to ensure compatibility with surgical requirements. In addition, these hydrogels exhibited compression moduli in the range of 40 to 145 kPa, which are substantially higher than those of previously developed elastin-based hydrogels. These hydrogels were highly stable in the physiological environment with the evidence of 10 wt% mass loss in 30 days of incubation in a simulated environment. This class of hydrogels is in vivo bioabsorbable due to the gradual increase of the lower critical solution temperature of the copolymer to above 37 °C due to the cleavage of polylactide from

Experimental study of combustion and emission characteristics of ethanol fuelled port injected homogeneous charge compression ignition (HCCI) combustion engine

Energy Technology Data Exchange (ETDEWEB)

Maurya, Rakesh Kumar; Agarwal, Avinash Kumar [Engine Research Laboratory, Department of Mechanical Engineering, Indian Institute of Technology Kanpur, Kanpur 208 016 (India)

2011-04-15

The homogeneous charge compression ignition (HCCI) is an alternative combustion concept for in reciprocating engines. The HCCI combustion engine offers significant benefits in terms of its high efficiency and ultra low emissions. In this investigation, port injection technique is used for preparing homogeneous charge. The combustion and emission characteristics of a HCCI engine fuelled with ethanol were investigated on a modified two-cylinder, four-stroke engine. The experiment is conducted with varying intake air temperature (120-150 C) and at different air-fuel ratios, for which stable HCCI combustion is achieved. In-cylinder pressure, heat release analysis and exhaust emission measurements were employed for combustion diagnostics. In this study, effect of intake air temperature on combustion parameters, thermal efficiency, combustion efficiency and emissions in HCCI combustion engine is analyzed and discussed in detail. The experimental results indicate that the air-fuel ratio and intake air temperature have significant effect on the maximum in-cylinder pressure and its position, gas exchange efficiency, thermal efficiency, combustion efficiency, maximum rate of pressure rise and the heat release rate. Results show that for all stable operation points, NO{sub x} emissions are lower than 10 ppm however HC and CO emissions are higher. (author)

Collective properties of injection-induced earthquake sequences: 1. Model description and directivity bias

Science.gov (United States)

Dempsey, David; Suckale, Jenny

2016-05-01

Induced seismicity is of increasing concern for oil and gas, geothermal, and carbon sequestration operations, with several M > 5 events triggered in recent years. Modeling plays an important role in understanding the causes of this seismicity and in constraining seismic hazard. Here we study the collective properties of induced earthquake sequences and the physics underpinning them. In this first paper of a two-part series, we focus on the directivity ratio, which quantifies whether fault rupture is dominated by one (unilateral) or two (bilateral) propagating fronts. In a second paper, we focus on the spatiotemporal and magnitude-frequency distributions of induced seismicity. We develop a model that couples a fracture mechanics description of 1-D fault rupture with fractal stress heterogeneity and the evolving pore pressure distribution around an injection well that triggers earthquakes. The extent of fault rupture is calculated from the equations of motion for two tips of an expanding crack centered at the earthquake hypocenter. Under tectonic loading conditions, our model exhibits a preference for unilateral rupture and a normal distribution of hypocenter locations, two features that are consistent with seismological observations. On the other hand, catalogs of induced events when injection occurs directly onto a fault exhibit a bias toward ruptures that propagate toward the injection well. This bias is due to relatively favorable conditions for rupture that exist within the high-pressure plume. The strength of the directivity bias depends on a number of factors including the style of pressure buildup, the proximity of the fault to failure and event magnitude. For injection off a fault that triggers earthquakes, the modeled directivity bias is small and may be too weak for practical detection. For two hypothetical injection scenarios, we estimate the number of earthquake observations required to detect directivity bias.

A strong steric hindrance effect on ground state, excited state, and charge separated state properties of a CuI-diimine complex captured by X-ray transient absorption spectroscopy

DEFF Research Database (Denmark)

Huang, J.; Mara, M.W.; Stickrath, A.B.

2014-01-01

of phenanthroline. The structural dynamics of the photoinduced charge transfer process in the [CuI(dppS)2]+/TiO2 hybrid is also investigated, which suggests a more restricted environment for the complex upon binding to TiO2 NPs. Moreover, the Cu-N bond length of the oxidized state of [CuI(dppS)2]+ after electron...... dynamics and structures as well as those of the charge separated state resulting from the interfacial electron injection from the MLCT state to TiO2 nanoparticles (NPs). The OTA results show the absence of the sub-picosecond component previously assigned as the time constant for flattening, while the two...... injection to TiO2 NPs shortens by 0.05 Å compared to that in the ground state. The interpretation of these observed structural changes associated with excited and charge separated states will be discussed. These results not only set an example for applying XTA in capturing the intermediate structure...

Microscopic and macroscopic characterization of the charging effects in SiC/Si nanocrystals/SiC sandwiched structures

International Nuclear Information System (INIS)

Xu, Jie; Xu, Jun; Wang, Yuefei; Cao, Yunqing; Li, Wei; Yu, Linwei; Chen, Kunji

2014-01-01

Microscopic charge injection into the SiC/Si nanocrystals/SiC sandwiched structures through a biased conductive AFM tip is subsequently characterized by both electrostatic force microscopy and Kelvin probe force microscopy (KPFM). The charge injection and retention characteristics are found to be affected by not only the band offset at the Si nanocrystals/SiC interface but also the doping type of the Si substrate. On the other hand, capacitance–voltage (C–V) measurements investigate the macroscopic charging effect of the sandwiched structures with a thicker SiC capping layer, where the charges are injected from the Si substrates. The calculated macroscopic charging density is 3–4 times that of the microscopic one, and the possible reason is the underestimation of the microscopic charging density caused by the averaging effect and detection delay in the KPFM measurements. (paper)

H- charge exchange injection for the NSNS accumulator

International Nuclear Information System (INIS)

Blumberg, L.N.; Lee, Y.Y.

1997-01-01

A scheme for injection into the FODO cell of the National Spallation Neutron Source (NSNS) Accumulator ring is discussed. A 400 μg/cm 2 carbon foil is chosen for a high stripping efficiency and for heating of the foil consideration. Additional schemes to reduce losses due to nuclear and Coulomb scattering at the foil are discussed. Subsequent loss from magnetic field ionization of the residual H 0 component is estimated to be small comparable to nuclear loss. A method for sweeping and collecting the stripped electrons from the foil is presented

Universal diffusion-limited injection and the hook effect in organic thin-film transistors

Science.gov (United States)

Liu, Chuan; Huseynova, Gunel; Xu, Yong; Long, Dang Xuan; Park, Won-Tae; Liu, Xuying; Minari, Takeo; Noh, Yong-Young

2016-01-01

The general form of interfacial contact resistance was derived for organic thin-film transistors (OTFTs) covering various injection mechanisms. Devices with a broad range of materials for contacts, semiconductors, and dielectrics were investigated and the charge injections in staggered OTFTs was found to universally follow the proposed form in the diffusion-limited case, which is signified by the mobility-dependent injection at the metal-semiconductor interfaces. Hence, real ohmic contact can hardly ever be achieved in OTFTs with low carrier concentrations and mobility, and the injection mechanisms include thermionic emission, diffusion, and surface recombination. The non-ohmic injection in OTFTs is manifested by the generally observed hook shape of the output conductance as a function of the drain field. The combined theoretical and experimental results show that interfacial contact resistance generally decreases with carrier mobility, and the injection current is probably determined by the surface recombination rate, which can be promoted by bulk-doping, contact modifications with charge injection layers and dopant layers, and dielectric engineering with high-k dielectric materials. PMID:27440253

Investigation of magnetic and magneto-transport properties of ferromagnetic-charge ordered core-shell nanostructures

Science.gov (United States)

Das, Kalipada

2017-10-01

In our present study, we address in detail the magnetic and magneto-transport properties of ferromagnetic-charge ordered core-shell nanostructures. In these core-shell nanostructures, well-known half metallic La0.67Sr0.33MnO3 nanoparticles (average particle size, ˜20 nm) are wrapped by the charge ordered antiferromagnetic Pr0.67Ca0.33MnO3 (PCMO) matrix. The intrinsic properties of PCMO markedly modify it into such a core-shell form. The robustness of the PCMO matrix becomes fragile and melts at an external magnetic field (H) of ˜20 kOe. The analysis of magneto-transport data indicates the systematic reduction of the electron-electron and electron-magnon interactions in the presence of an external magnetic field in these nanostructures. The pronounced training effect appears in this phase separated compound, which was analyzed by considering the second order tunneling through the grain boundaries of the nanostructures. Additionally, the analysis of low field magnetoconductance data supports the second order tunneling and shows the close value of the universal limit (˜1.33).

Microparticle injection effects on microwave transmission through an overly dense plasma layer

Energy Technology Data Exchange (ETDEWEB)

Gillman, Eric D., E-mail: eric.gillman@nrl.navy.mil; Amatucci, W. E. [Naval Research Laboratory, Washington, DC 20375 (United States); Williams, Jeremiah [Wittenberg University, Springfield, Ohio 45501 (United States); Compton, C. S. [Sotera Defense Solutions, Herndon, Virginia 20171 (United States)

2015-04-15

Microparticles injected into a plasma have been shown to deplete the free electron population as electrons are collected through the process of microparticles charging to the plasma floating potential. However, these charged microparticles can also act to scatter electromagnetic signals. These experiments investigate microwave penetration through a previously impenetrable overly dense plasma layer as microparticles are injected and the physical phenomena associated with the competing processes that occur due to electron depletion and microwave scattering. The timescales for when each of these competing processes dominates is analyzed in detail. It was found that while both processes play a significant and dominant role at different times, ultimately, transmission through this impenetrable plasma layer can be significantly increased with microparticle injection.

Artificially injected charged particles as a tool for the measurement of the electric field in the magnetosphere

International Nuclear Information System (INIS)

Pirre, M.

1982-01-01

Two methods of measuring the parallel electric field in the magnetosphere using artificially injected charged particles are discussed. One method uses electrons to measure the parallel electric field in the vicinity of the spacecraft. It is shown that a very good accuracy can be achieved for such a measurement. The principle of this method is briefly reviewed, the minimum theoretical value measurable by the method is shown, and the limitations on it due to the spacecraft environment are discussed. Most important among the latter is the high level of turbulence about the spacecraft. The second method uses ions to measure the electric potential along the magnetic field lines if the associated parallel electric field is directed downward. For such a field at a lower altitude, Li ions are used to maximize the returning fluxes and to increase the probability of detection. Rockets are more suitable than satellites to make such measurements. 17 references

Semiconducting lithium indium diselenide: Charge-carrier properties and the impacts of high flux thermal neutron irradiation

Science.gov (United States)

Hamm, Daniel S.; Rust, Mikah; Herrera, Elan H.; Matei, Liviu; Buliga, Vladimir; Groza, Michael; Burger, Arnold; Stowe, Ashley; Preston, Jeff; Lukosi, Eric D.

2018-06-01

This paper reports on the charge carrier properties of several lithium indium diselenide (LISe) semiconductors. It was found that the charge collection efficiency of LISe was improved after high flux thermal neutron irradiation including the presence of a typically unobservable alpha peak from hole-only collection. Charge carrier trap energies of the irradiated sample were measured using photo-induced current transient spectroscopy. Compared to previous studies of this material, no significant differences in trap energies were observed. Through trap-filled limited voltage measurements, neutron irradiation was found to increase the density of trap states within the bulk of the semiconductor, which created a polarization effect under alpha exposure but not neutron exposure. Further, the charge collection efficiency of the irradiated sample was higher (14-15 fC) than that of alpha particles (3-5 fC), indicating that an increase in hole signal contribution resulted from the neutron irradiation. Finally, it was observed that significant charge loss takes place near the point of generation, producing a significant scintillation response and artificially inflating the W-value of all semiconducting LISe crystals.

Electronic and vibronic properties of a discotic liquid-crystal and its charge transfer complex

Energy Technology Data Exchange (ETDEWEB)

Haverkate, Lucas A.; Mulder, Fokko M. [Reactor Institute Delft, Faculty of Applied Sciences, Delft University of Technology, Mekelweg 15, 2629JB Delft (Netherlands); Zbiri, Mohamed, E-mail: zbiri@ill.fr; Johnson, Mark R. [Institut Laue Langevin, 38042 Grenoble Cedex 9 (France); Carter, Elizabeth [Vibrational Spectroscopy Facility, School of Chemistry, The University of Sydney, NSW 2008 (Australia); Kotlewski, Arek; Picken, S. [ChemE-NSM, Faculty of Chemistry, Delft University of Technology, 2628BL/136 Delft (Netherlands); Kearley, Gordon J. [Bragg Institute, Australian Nuclear Science and Technology Organisation, Menai, NSW 2234 (Australia)

2014-01-07

Discotic liquid crystalline (DLC) charge transfer (CT) complexes combine visible light absorption and rapid charge transfer characteristics, being favorable properties for photovoltaic (PV) applications. We present a detailed study of the electronic and vibrational properties of the prototypic 1:1 mixture of discotic 2,3,6,7,10,11-hexakishexyloxytriphenylene (HAT6) and 2,4,7-trinitro-9-fluorenone (TNF). It is shown that intermolecular charge transfer occurs in the ground state of the complex: a charge delocalization of about 10{sup −2} electron from the HAT6 core to TNF is deduced from both Raman and our previous NMR measurements [L. A. Haverkate, M. Zbiri, M. R. Johnson, B. Deme, H. J. M. de Groot, F. Lefeber, A. Kotlewski, S. J. Picken, F. M. Mulder, and G. J. Kearley, J. Phys. Chem. B 116, 13098 (2012)], implying the presence of permanent dipoles at the donor-acceptor interface. A combined analysis of density functional theory calculations, resonant Raman and UV-VIS absorption measurements indicate that fast relaxation occurs in the UV region due to intramolecular vibronic coupling of HAT6 quinoidal modes with lower lying electronic states. Relatively slower relaxation in the visible region the excited CT-band of the complex is also indicated, which likely involves motions of the TNF nitro groups. The fast quinoidal relaxation process in the hot UV band of HAT6 relates to pseudo-Jahn-Teller interactions in a single benzene unit, suggesting that the underlying vibronic coupling mechanism can be generic for polyaromatic hydrocarbons. Both the presence of ground state CT dipoles and relatively slow relaxation processes in the excited CT band can be relevant concerning the design of DLC based organic PV systems.

Space-charge-limited currents: An E-infinity Cantorian approach

Czech Academy of Sciences Publication Activity Database

Zmeškal, O.; Nešpůrek, Stanislav; Weiter, M.

2007-01-01

Roč. 34, č. 2 (2007), s. 143-158 ISSN 0960-0779 R&D Projects: GA MPO FT-TA/036; GA AV ČR IAA100100622 Institutional research plan: CEZ:AV0Z40500505 Keywords : space charge * fractal * charge injection Subject RIV: CD - Macromolecular Chemistry Impact factor: 3.025, year: 2007

Study Trapped Charge Distribution in P-Channel Silicon-Oxide-Nitride-Oxide-Silicon Memory Device Using Dynamic Programming Scheme

Science.gov (United States)

Li, Fu-Hai; Chiu, Yung-Yueh; Lee, Yen-Hui; Chang, Ru-Wei; Yang, Bo-Jun; Sun, Wein-Town; Lee, Eric; Kuo, Chao-Wei; Shirota, Riichiro

2013-04-01

In this study, we precisely investigate the charge distribution in SiN layer by dynamic programming of channel hot hole induced hot electron injection (CHHIHE) in p-channel silicon-oxide-nitride-oxide-silicon (SONOS) memory device. In the dynamic programming scheme, gate voltage is increased as a staircase with fixed step amplitude, which can prohibits the injection of holes in SiN layer. Three-dimensional device simulation is calibrated and is compared with the measured programming characteristics. It is found, for the first time, that the hot electron injection point quickly traverses from drain to source side synchronizing to the expansion of charged area in SiN layer. As a result, the injected charges quickly spread over on the almost whole channel area uniformly during a short programming period, which will afford large tolerance against lateral trapped charge diffusion by baking.

Highly efficient tandem OLED based on C{sub 60}/rubrene: MoO{sub 3} as charge generation layer and LiF/Al as electron injection layer

Energy Technology Data Exchange (ETDEWEB)

Liu, Yang [School of Materials Science and Engineering, Tianjin University of Technology, Tianjin 300384 (China); Key Laboratory of Display Materials and Photoelectric Devices, Ministry of Education, Tianjin 300384 (China); Tianjin Key Laboratory of Photoelectric Materials and Devices, Tianjin 300384 (China); College of Science, Tianjin University of Technology, Tianjin 300384 (China); Wu, Xiaoming, E-mail: wxm@tjut.edu.cn [School of Materials Science and Engineering, Tianjin University of Technology, Tianjin 300384 (China); Key Laboratory of Display Materials and Photoelectric Devices, Ministry of Education, Tianjin 300384 (China); Tianjin Key Laboratory of Photoelectric Materials and Devices, Tianjin 300384 (China); Xiao, Zhihui; Gao, Jian; Zhang, Juan; Rui, Hongsong; Lin, Xin; Zhang, Nan; Hua, Yulin [School of Materials Science and Engineering, Tianjin University of Technology, Tianjin 300384 (China); Key Laboratory of Display Materials and Photoelectric Devices, Ministry of Education, Tianjin 300384 (China); Tianjin Key Laboratory of Photoelectric Materials and Devices, Tianjin 300384 (China); Yin, Shougen, E-mail: sgyin@tjut.edu.cn [School of Materials Science and Engineering, Tianjin University of Technology, Tianjin 300384 (China); Key Laboratory of Display Materials and Photoelectric Devices, Ministry of Education, Tianjin 300384 (China); Tianjin Key Laboratory of Photoelectric Materials and Devices, Tianjin 300384 (China)

2017-08-15

Highlights: • Highly efficient blue fluorescent tandem OLEDs are fabricated. • The optimal tandem OLED consists of C{sub 60}/rubrene: MoO{sub 3} as a CGL and LiF/Al as an EIL. • Current efficiency and power efficiency of optimal tandem OLED is markedly enhanced. • The turn-on and driving voltages of optimal tandem OLED is obviously reduced. - Abstract: Tandem organic light-emitting diodes (OLEDs) have received much attention in solid-state lighting due to their high current efficiency, long lifetime and excellent stability. The highly efficient blue fluorescent tandem OLEDs based on the charge generation layer (CGL) of C{sub 60}/rubrene: MoO{sub 3} and the electron injection layer (EIL) of LiF/Al were fabricated. The ultra-thin Al layer in EIL was introduced to further increase electron injection from CGL to the emission unit. We found that the maximal current efficiency and power efficiency of optimal tandem device can reach to 43.1 cd/A and 15.1 lm/W, respectively, which are approximately 2.8 and 1.9 times compared with those of single-emissive-unit device. Moreover, compared with the traditional tandem device, the driving voltage of the optimal device is reduced by 6 V, and the turn-on voltage is reduced by 2.4 V. We analyzed the mechanism and characterization of these tandem devices. The effective charge separation and transport of C{sub 60}/rubrene: MoO{sub 3}, and excellent electron injection ability of ultra-thin Al layer are the main factors for the remarkable enhancement in both current efficiency and power efficiency of tandem OLEDs.

Electron beam charge state amplifier (EBQA)--a conceptual evaluation

International Nuclear Information System (INIS)

Dooling, J. C.

1998-01-01

A concept is presented for stripping low-energy, radioactive ions from 1+ to higher charge states. Referred to as an Electron Beam Charge State Amplifier (EBQA), this device accepts a continuous beam of singly-charged, radioactive ions and passes them through a high-density electron beam confined by a solenoidal magnetic field. Singly-charged ions may be extracted from standard Isotope-Separator-Online (ISOL) sources. An EBQA is potentially useful for increasing the charge state of ions prior to injection into post-acceleration stages at ISOL radioactive beam facilities. The stripping efficiency from q=1+ to 2+ (η 12 ) is evaluated as a function of electron beam radius at constant current with solenoid field, injected ion energy, and ion beam emittance used as parameters. Assuming a 5 keV, 1 A electron beam, η 12 = 0.38 for 0.1 keV, 132 Xe ions passing through an 8 Tesla solenoid, 1 m in length. Multi-pass configurations to achieve 3+ or 4+ charge states are also conceivable. The calculated efficiencies depend inversely on the initial ion beam emittances. The use of a helium-buffer-gas, ion-guide stage to improve the brightness of the 1+ beams [1] may enhance the performance of an EBQA

Channel of Axial Injection of DC-60 Cyclotron

CERN Document Server

Gikal, B N; Bogomolov, S L; Borisenko, A N; Borisov, O N; Gulbekyan, G G; Ivanenko, I A; Kalagin, I V; Kazacha, V I; Kazarinov, N Yu; Khabarov, M V; Lysukhin, S N; Melnikov, V N; Paschenko, S V; Tikhomirov, A V

2006-01-01

The design study and realization of the axial injection beam line of DC-60 cyclotron constructed at the Flerov Laboratory of Nuclear Reactions of the Joint Institute for Nuclear Research are given. The channel allows one to transport and to inject into the cyclotron ions with mass-to-charge ratio $A/Z$ being within interval A/Z=6-12 and kinetic energy up to 17 $Z/A$ keV/m.u.

Charge distribution of metallic single walled carbon nanotube–graphene junctions

International Nuclear Information System (INIS)

Robert, P T; Danneau, R

2014-01-01

We report numeric and analytic calculations of the electrostatic properties for armchair carbon nanotube–graphene junctions. Using a semi-empirical method we first demonstrate that the equilibrium distance between a carbon nanotube and a graphene sheet varies with respect to the diameter of the carbon nanotube. We find significantly reduced values compared to AB-stacked graphene sheets in graphite, while even smaller value is found for a fullerene C 60 implying a dimensionality dependence of the equilibrium distance between graphene and the other sp 2 carbon allotropes. Then, we use conformal mapping and a charge–dipole model to study the charge distribution of the carbon nanotube–graphene junctions in various configurations. We observe that the charges are accumulated/depleted at and near the vicinity of the junctions and that capped carbon nanotubes induce a significantly smaller charge concentration at their ends than the open-end nanotubes. We demonstrate that the carbon nanotube influence on the graphene sheet is limited to only few atomic rows. Such an influence strongly depends on the distance between carbon nanotube and the graphene sheet and scales with the carbon nanotube radius, while the potential difference does not modify the length over which the charge concentration is disturbed by the presence of the tube. By studying the potential landscape of carbon nanotube–graphene junctions, our work could be used as a starting point to model the charge carrier injection in these unconventional systems. (paper)

Investigation on transient flow of a centrifugal charging pump in the process of high pressure safety injection

Energy Technology Data Exchange (ETDEWEB)

Zhang, Fan, E-mail: zhangfan4060@gmail.com; Yuan, Shouqi; Fu, Qiang; Tao, Yi

2015-11-15

Highlights: • The transient flow characteristics of the charging pump with the first stage impeller in the HPSI process have been investigated numerically by CFD. • The hydraulic performance of the charging pump during the HPSI are discussed, andthe absolute errors between the simulated and measured results are analyzed in the paper. • Pressure fluctuation in the impeller and flow pattern in the impeller were studied in the HPSI process. It is influenced little at the beginning of the HPSI process while fluctuates strongly in the end of the HPSI process. - Abstract: In order to investigate the transient flow characteristics of the centrifugal charging pump during the transient transition process of high pressure safety injection (HPSI) from Q = 148 m{sup 3}/h to Q = 160 m{sup 3}/h, numerical simulation and experiment are implemented in this study. The transient flow rate, which is the most important factor, is obtained from the experiment and works as the boundary condition to accurately accomplish the numerical simulation in the transient process. Internal characteristics under the variable operating conditions are analyzed through the transient simulation. The results shows that the absolute error between the simulated and measured heads is less than 2.26% and the absolute error between the simulated and measured efficiency is less than 2.04%. Pressure fluctuation in the impeller is less influenced by variable flow rate in the HPSI process, while flow pattern in the impeller is getting better and better with the flow rate increasing. As flow rate increases, fluid blocks on the tongue of the volute and it strikes in this area at large flow rate. Correspondingly, the pressure fluctuation is intense and vortex occurs gradually during this period, which obviously lowers the efficiency of the pump. The contents of the current work can provide references for the design optimization and fluid control of the pump used in the transient process of variable operating

Investigation on transient flow of a centrifugal charging pump in the process of high pressure safety injection

International Nuclear Information System (INIS)

Zhang, Fan; Yuan, Shouqi; Fu, Qiang; Tao, Yi

2015-01-01

Highlights: • The transient flow characteristics of the charging pump with the first stage impeller in the HPSI process have been investigated numerically by CFD. • The hydraulic performance of the charging pump during the HPSI are discussed, andthe absolute errors between the simulated and measured results are analyzed in the paper. • Pressure fluctuation in the impeller and flow pattern in the impeller were studied in the HPSI process. It is influenced little at the beginning of the HPSI process while fluctuates strongly in the end of the HPSI process. - Abstract: In order to investigate the transient flow characteristics of the centrifugal charging pump during the transient transition process of high pressure safety injection (HPSI) from Q = 148 m"3/h to Q = 160 m"3/h, numerical simulation and experiment are implemented in this study. The transient flow rate, which is the most important factor, is obtained from the experiment and works as the boundary condition to accurately accomplish the numerical simulation in the transient process. Internal characteristics under the variable operating conditions are analyzed through the transient simulation. The results shows that the absolute error between the simulated and measured heads is less than 2.26% and the absolute error between the simulated and measured efficiency is less than 2.04%. Pressure fluctuation in the impeller is less influenced by variable flow rate in the HPSI process, while flow pattern in the impeller is getting better and better with the flow rate increasing. As flow rate increases, fluid blocks on the tongue of the volute and it strikes in this area at large flow rate. Correspondingly, the pressure fluctuation is intense and vortex occurs gradually during this period, which obviously lowers the efficiency of the pump. The contents of the current work can provide references for the design optimization and fluid control of the pump used in the transient process of variable operating conditions.

Effects of moulding and environmental conditions on the mechanical and surface properties of injection moulded santoprene rubber

DEFF Research Database (Denmark)

Islam, Aminul; Ruby, Tobias M.; Jessen, Rikke L.

the electronics inside from environmental hazards. The sealing ring is injection moulded in Santoprene-a thermoplastic vulcanizate consisting of Polypropelene and highly vulcanized EPDM rubber. The scope of the project was therefore to investigate the properties of Santoprene and make an immediate evaluation...

Ultrahigh mobility and efficient charge injection in monolayer organic thin-film transistors on boron nitride.

Science.gov (United States)

He, Daowei; Qiao, Jingsi; Zhang, Linglong; Wang, Junya; Lan, Tu; Qian, Jun; Li, Yun; Shi, Yi; Chai, Yang; Lan, Wei; Ono, Luis K; Qi, Yabing; Xu, Jian-Bin; Ji, Wei; Wang, Xinran

2017-09-01

Organic thin-film transistors (OTFTs) with high mobility and low contact resistance have been actively pursued as building blocks for low-cost organic electronics. In conventional solution-processed or vacuum-deposited OTFTs, due to interfacial defects and traps, the organic film has to reach a certain thickness for efficient charge transport. Using an ultimate monolayer of 2,7-dioctyl[1]benzothieno[3,2- b ][1]benzothiophene (C 8 -BTBT) molecules as an OTFT channel, we demonstrate remarkable electrical characteristics, including intrinsic hole mobility over 30 cm 2 /Vs, Ohmic contact with 100 Ω · cm resistance, and band-like transport down to 150 K. Compared to conventional OTFTs, the main advantage of a monolayer channel is the direct, nondisruptive contact between the charge transport layer and metal leads, a feature that is vital for achieving low contact resistance and current saturation voltage. On the other hand, bilayer and thicker C 8 -BTBT OTFTs exhibit strong Schottky contact and much higher contact resistance but can be improved by inserting a doped graphene buffer layer. Our results suggest that highly crystalline molecular monolayers are promising form factors to build high-performance OTFTs and investigate device physics. They also allow us to precisely model how the molecular packing changes the transport and contact properties.

Injection Locking of a Semiconductor Double Quantum Dot Micromaser.

Science.gov (United States)

Liu, Y-Y; Stehlik, J; Gullans, M J; Taylor, J M; Petta, J R

2015-11-01

Emission linewidth is an important figure of merit for masers and lasers. We recently demonstrated a semiconductor double quantum dot (DQD) micromaser where photons are generated through single electron tunneling events. Charge noise directly couples to the DQD energy levels, resulting in a maser linewidth that is more than 100 times larger than the Schawlow-Townes prediction. Here we demonstrate a linewidth narrowing of more than a factor 10 by locking the DQD emission to a coherent tone that is injected to the input port of the cavity. We measure the injection locking range as a function of cavity input power and show that it is in agreement with the Adler equation. The position and amplitude of distortion sidebands that appear outside of the injection locking range are quantitatively examined. Our results show that this unconventional maser, which is impacted by strong charge noise and electron-phonon coupling, is well described by standard laser models.

Molding Properties of Inconel 718 Feedstocks Used in Low-Pressure Powder Injection Molding

Directory of Open Access Journals (Sweden)

Fouad Fareh

2016-01-01

Full Text Available The impact of binders and temperature on the rheological properties of feedstocks used in low-pressure powder injection molding was investigated. Experiments were conducted on different feedstock formulations obtained by mixing Inconel 718 powder with wax-based binder systems. The shear rate sensitivity index and the activation energy were used to study the degree of dependence of shear rate and temperature on the viscosity of the feedstocks. The injection performance of feedstocks was then evaluated using an analytical moldability model. The results indicated that the viscosity profiles of feedstocks depend significantly on the binder constituents, and the secondary binder constituents play an important role in the rheological behavior (pseudoplastic or near-Newtonian exhibited by the feedstock formulations. Viscosity values as low as 0.06 to 2.9 Pa·s were measured at high shear rates and high temperatures. The results indicate that a feedstock containing a surfactant agent exhibits the best moldability characteristics.

Photoelectric schlieren method used to study the properties of diesel engine injection systems

International Nuclear Information System (INIS)

Reznicek, R.

1987-01-01

The time dependence of the fuel flow rate issuing from the injector nozzle represents very important information concerning the properties of Diesel engine injection systems. By analysing the delivery rate, it is possible to judge a new design, and the modifications and adjustments of Diesel engine injection systems. A number of devices for measuring the delivery rate, frequently founded on mechanical principles, have also been constructed. Mechanical methods are laborious, require complicated measuring instruments, and the analysis of the results is quite tedious. For investigating the delivery rate, one can also use the intensity of the luminous flux of the light ray which is intersected, and consequently its intensity decreased, by the flow of the delivered fuel. The schlieren method can be used for this purpose, employing a thin beam of parallel light rays and a photoelectric sensor placed immediately beyond the cut-off slit. After adjustment and calibration, the variations of the original electric signal represent the time variation of the delivery rate by the nozzle

Commissioning results of the ReA EBIT charge breeder at the NSCL: First reacceleration of stable-isotope beams

Energy Technology Data Exchange (ETDEWEB)

Lapierre, A., E-mail: lapierre@nscl.msu.edu; Schwarz, S.; Kittimanapun, K.; Rodriguez, J.A.; Sumithrarachchi, C.; Barquest, B.; Berryman, E.; Cooper, K.; Fogleman, J.; Krause, S.; Kwarsick, J.; Nash, S.; Perdikakis, G.; Portillo, M.; Rencsok, R.; Skutt, D.; Steiner, M.; Tobos, L.; Wittmer, W.; Bollen, G.; and others

2013-12-15

Highlights: • Latest results with the electron-beam ion trap of the ReA post-accelerator at the NSCL. • First reacceleration of stable-isotope beams. • First injection of stable-isotope beams from the NSCL’s beam stopping vault. -- Abstract: ReA is a reaccelerator of rare-isotope beams at the National Superconducting Cyclotron Laboratory (NSCL). The rare isotopes are produced by fast projectile fragmentation. After production, they are separated in-flight and thermalized in a He gas “catcher” cell before being sent to ReA for reacceleration to a few MeV/u. One of its main components is an electron-beam ion trap (EBIT) employed to convert injected singly charged ions to highly charged ions prior to injection into linear-accelerator structures. The ReA EBIT features a high-current electron gun, a long trap structure, and a two-field superconducting magnet to provide both the high electron-beam current density needed for fast charge breeding and high capture probability of injected beams. This paper presents recent commissioning results. In particular, {sup 39}K{sup +} ions have been injected, charge bred to {sup 39}K{sup 16+} and extracted for reacceleration up to 60 MeV. First charge-breeding results of beams injected from a commissioning Rb ion source in the NSCL’s beam “stopping” vault are also presented.

Single-shot measurements of low emittance beams from laser-plasma accelerators comparing two triggered injection methods

Science.gov (United States)

van Tilborg, Jeroen

2017-10-01

The success of laser plasma accelerator (LPA) based applications, such as a compact x-ray free electron laser (FEL), relies on the ability to produce electron beams with excellent 6D brightness, where brightness is defined as the ratio of charge to the product of the three normalized emittances. As such, parametric studies of the emittance of LPA generated electron beams are essential. Profiting from a stable and tunable LPA setup, combined with a carefully designed single-shot energy-dispersed emittance diagnostic, we present a direct comparison of charge dependent emittance measurements of electron beams generated by two different injection mechanisms: ionization injection and shock-induced density down-ramp injection. Both injection mechanisms have gained in popularity in recent years due to their demonstrated stable LPA performance. For the down-ramp injection configuration, normalized emittances a factor of two lower were recorded: less than 1 micron at spectral charge densities up to 2 pC/MeV. For both injection mechanisms, a contributing correlation of space charge to the emittance was identified. This measurement technique in general, and these results specifically, are critical to the evaluation of LPA injection methods and development of high-quality LPA beam lines worldwide. This work is supported by the U.S. DOE under Contract No. DE-AC02-05CH11231, by the U.S. DOE NNSA, DNN R&D (NA22), by the National Science Foundation under Grant No. PHY-1415596, and by the Gordon and Betty Moore Foundation under Grant ID GBMF4898.

Pore structure and function of synthetic nanopores with fixed charges: tip shape and rectification properties

Energy Technology Data Exchange (ETDEWEB)

RamIrez, Patricio [Departament de Fisica Aplicada, Universitat Politecnica de Valencia, E-46022 Valencia (Spain); Apel, Pavel Yu [Flerov Laboratory of Nuclear Reactions, Joint Institute for Nuclear Research, Joliot-Curie street 6, 141980 Dubna (Russian Federation); Cervera, Javier; Mafe, Salvador [Departament de Fisica de la Terra i Termodinamica, Universitat de Valencia, E-46100 Burjassot (Spain)], E-mail: patraho@fis.upv.es

2008-08-06

We present a complete theoretical study of the relationship between the structure (tip shape and dimensions) and function (selectivity and rectification) of asymmetric nanopores on the basis of previous experimental studies. The theoretical model uses a continuum approach based on the Nernst-Planck equations. According to our results, the nanopore transport properties, such as current-voltage (I-V) characteristics, conductance, rectification ratio, and selectivity, are dictated mainly by the shape of the pore tip (we have distinguished bullet-like, conical, trumpet-like, and hybrid shapes) and the concentration of pore surface charges. As a consequence, the nanopore performance in practical applications will depend not only on the base and tip openings but also on the pore shape. In particular, we show that the pore opening dimensions estimated from the pore conductance can be very different, depending on the pore shape assumed. The results obtained can also be of practical relevance for the design of nanopores, nanopipettes, and nanoelectrodes, where the electrical interactions between the charges attached to the nanostructure and the mobile charges confined in the reduced volume of the inside solution dictate the device performance in practical applications. Because single tracks are the elementary building blocks for nanoporous membranes, the understanding and control of their individual properties should also be crucial in protein separation, water desalination, and bio-molecule detection using arrays of identical nanopores.

Pore structure and function of synthetic nanopores with fixed charges: tip shape and rectification properties

International Nuclear Information System (INIS)

RamIrez, Patricio; Apel, Pavel Yu; Cervera, Javier; Mafe, Salvador

2008-01-01

We present a complete theoretical study of the relationship between the structure (tip shape and dimensions) and function (selectivity and rectification) of asymmetric nanopores on the basis of previous experimental studies. The theoretical model uses a continuum approach based on the Nernst-Planck equations. According to our results, the nanopore transport properties, such as current-voltage (I-V) characteristics, conductance, rectification ratio, and selectivity, are dictated mainly by the shape of the pore tip (we have distinguished bullet-like, conical, trumpet-like, and hybrid shapes) and the concentration of pore surface charges. As a consequence, the nanopore performance in practical applications will depend not only on the base and tip openings but also on the pore shape. In particular, we show that the pore opening dimensions estimated from the pore conductance can be very different, depending on the pore shape assumed. The results obtained can also be of practical relevance for the design of nanopores, nanopipettes, and nanoelectrodes, where the electrical interactions between the charges attached to the nanostructure and the mobile charges confined in the reduced volume of the inside solution dictate the device performance in practical applications. Because single tracks are the elementary building blocks for nanoporous membranes, the understanding and control of their individual properties should also be crucial in protein separation, water desalination, and bio-molecule detection using arrays of identical nanopores

Pore structure and function of synthetic nanopores with fixed charges: tip shape and rectification properties.

Science.gov (United States)

Ramírez, Patricio; Apel, Pavel Yu; Cervera, Javier; Mafé, Salvador

2008-08-06

We present a complete theoretical study of the relationship between the structure (tip shape and dimensions) and function (selectivity and rectification) of asymmetric nanopores on the basis of previous experimental studies. The theoretical model uses a continuum approach based on the Nernst-Planck equations. According to our results, the nanopore transport properties, such as current-voltage (I-V) characteristics, conductance, rectification ratio, and selectivity, are dictated mainly by the shape of the pore tip (we have distinguished bullet-like, conical, trumpet-like, and hybrid shapes) and the concentration of pore surface charges. As a consequence, the nanopore performance in practical applications will depend not only on the base and tip openings but also on the pore shape. In particular, we show that the pore opening dimensions estimated from the pore conductance can be very different, depending on the pore shape assumed. The results obtained can also be of practical relevance for the design of nanopores, nanopipettes, and nanoelectrodes, where the electrical interactions between the charges attached to the nanostructure and the mobile charges confined in the reduced volume of the inside solution dictate the device performance in practical applications. Because single tracks are the elementary building blocks for nanoporous membranes, the understanding and control of their individual properties should also be crucial in protein separation, water desalination, and bio-molecule detection using arrays of identical nanopores.

Theoretical Investigation on Charge Transfer Properties of 1,3,5-Tripyrrolebenzene (TPB and its Derivatives with Electron-withdrawing Substituents

Directory of Open Access Journals (Sweden)

Yong Hu

2016-06-01

Full Text Available The electronic structures and charge transport properties of 1,3,5-tripyrrolebenzene (TPB and its substituted derivatives with –F and –CN groups have been investigated by DFT calculations in combination with the Marcus hopping model. The dimer geometry was optimized by density functional theory method with dispersion force correction being included (DFT-D. Consequently, the charge transfer integral was evaluated. The calculation results show that the introduction of electron-withdrawing substituents does not significantly change the bond lengths and molecular symmetry of TPB, but lower the coplanarity between the pyrrole and benzene rings, especially in the case of CN substitution. Meanwhile, the introduction of electron-withdrawing groups can decrease the energy of the frontier molecular orbital and enhance the air stability. Fluorination makes the λe increase obviously while cyanation dose not. Generally speaking, the λe values of the title compounds are larger than their λh. Except for compounds 6 and 9, all others keep the face to face packing or have a slight slip in dimers, but the center of mass distances increase after fluorination or cyanation due to the distortion of the monomer’s coplanarity. The predicted quasi-one-dimensional electron mobility of the dimers is up to 0.433 cm2 V-1 s-1 at 298.15 K. The electron injection barriers of 2 and 7 are lower than that of TPB. The TPB derivatives of 1, 2, and 7 are potential n-channel materials with the high electron mobility. This work is licensed under a Creative Commons Attribution 4.0 International License.

Advanced diesel electronic fuel injection and turbocharging

Science.gov (United States)

Beck, N. J.; Barkhimer, R. L.; Steinmeyer, D. C.; Kelly, J. E.

1993-12-01

The program investigated advanced diesel air charging and fuel injection systems to improve specific power, fuel economy, noise, exhaust emissions, and cold startability. The techniques explored included variable fuel injection rate shaping, variable injection timing, full-authority electronic engine control, turbo-compound cooling, regenerative air circulation as a cold start aid, and variable geometry turbocharging. A Servojet electronic fuel injection system was designed and manufactured for the Cummins VTA-903 engine. A special Servojet twin turbocharger exhaust system was also installed. A series of high speed combustion flame photos was taken using the single cylinder optical engine at Michigan Technological University. Various fuel injection rate shapes and nozzle configurations were evaluated. Single-cylinder bench tests were performed to evaluate regenerative inlet air heating techniques as an aid to cold starting. An exhaust-driven axial cooling air fan was manufactured and tested on the VTA-903 engine.

Optical and electrical properties of negatively charged aluminium oxynitride films

Energy Technology Data Exchange (ETDEWEB)

Jang, Kyungsoo; Jung, Sungwook; Lee, Jeoungin; Lee, Kwangsoo; Kim, Jaehong; Son, Hyukjoo [School of information and communication Engineering, Sungkyunkwan University, 300 Chunchun-dong, Jangan-gu, Suwon, 440-746 (Korea, Republic of); Yi, Junsin [School of information and communication Engineering, Sungkyunkwan University, 300 Chunchun-dong, Jangan-gu, Suwon, 440-746 (Korea, Republic of)], E-mail: yi@yurim.ac.kr

2008-11-03

Aluminium oxynitride (AlON) thin films were deposited by Radio Frequency (RF) magnetron sputtering on n-type silicon (Si) substrate of (100) orientation using argon (Ar) and oxygen (O{sub 2}) gases at substrate temperature of 450 {sup o}C. To know the change in electrical properties with gases ratio, a deposition was carried out for 140 s with Ar:O{sub 2} ratio changed from 1:3 to 4:3. After that, electrical properties of Metal-Insulator-Semiconductor (MIS) structure with AlON was analyzed. For Ar:O{sub 2} ratios from 1:3 to 4:3, all samples showed characteristics of negative charge. In particular, when Ar:O{sub 2} were 2:3 and 3:3, the value of flatband voltage in normal C-V curve showed above 14 V. The composition of the AlON in the film was investigated using X-ray Photoelectron Spectroscopy (XPS). The flatband voltages (V{sub FB}) in C-V curves were found to depend on compositions. The characteristics of photon energy band gap were obtained by UV/VIS spectrum.

Measurements of the Properties of Highly-charged high-Z ions

International Nuclear Information System (INIS)

Augustine J. Smith, Ph.D.

2007-01-01

We had proposed carrying out a systematic experimental investigation of the atomic physics of highly charged, high-Z ions, produced in the Lawrence Livermore National Laboratory LLNL electron beam ion trap (EBIT-I) in its high energy mode, superEBIT. In particular we were going to accurately measure line positions for Δn=0 transitions in few electron high-Z ions; this was meant to enable us to investigate relativistic and quantum electrodynamics QED contributions to the energy levels as well as the nuclear properties of heavy ions. We were also going to measure cross sections for various electron-ion interactions, the degree of polarization of emitted x-rays, and radiation cooling rates of various ionization stages of highly charged, high-Z ions. This would enable us to study fundamental atomic physics of high-Z ions at relativistic electron impact energies and in the intense nuclear fields of highly ionized, high-Z ions. This would extend previous measurements we have carried out to a regime where there is a paucity of good data. These measurements were expected to generate increased theoretical interest and activity in this area. The project will extend a very successful collaboration between Morehouse College (MC) and a national laboratory LLNL, Minority student training and development are major components of the proposal

Study of status of safe injection practice and knowledge regarding injection safety among primary health care workers in Baglung district, western Nepal.

Science.gov (United States)

Gyawali, Sudesh; Rathore, Devendra S; Kc, Bhuvan; Shankar, P Ravi

2013-01-03

Unsafe injection practices and injection overuse are widespread in developing countries harming the patient and inviting risks to the health care workers. In Nepal, there is a dearth of documented information about injection practices so the present study was carried out: a) to determine whether the selected government health facilities satisfy the conditions for safe injections in terms of staff training, availability of sterile injectable equipment and their proper disposal after use and b) to assess knowledge and attitudes of healthcare workers in these health care facilities with regard to injection safety. A descriptive cross-sectional mixed type (qualitative and quantitative) survey was carried out from 18th May to 16th June 2012. In-depth interviews with the in-charges were conducted using a semi-structured questionnaire. Observation of the health facilities using a structured observation tool was done. The data were analysed manually by summarizing, tabulating and presenting in various formats. The in-charges (eight males, two females) who participated in the study ranged in age from 30 to 50 years with a mean age of 37.8 years. Severe infection followed by pain was the most important cause for injection use with injection Gentamicin being most commonly prescribed. New single use (disposable) injections and auto-disable syringes were used to inject curative drugs and vaccines respectively. Sufficient safety boxes were also supplied to dispose the used syringe. All health care workers had received full course of Hepatitis B vaccine and were knowledgeable about at least one pathogen transmitted through unsafe injection practices. Injection safety management policy and waste disposal guideline was not available for viewing in any of the facilities. The office staff who disposed the bio-medical wastes did so without taking any safety measures. Moreover, none of these staff had received any formal training in waste management. Certain safe injection

Study of status of safe injection practice and knowledge regarding injection safety among primary health care workers in Baglung district, western Nepal

Directory of Open Access Journals (Sweden)

Gyawali Sudesh

2013-01-01

Full Text Available Abstract Background Unsafe injection practices and injection overuse are widespread in developing countries harming the patient and inviting risks to the health care workers. In Nepal, there is a dearth of documented information about injection practices so the present study was carried out: a to determine whether the selected government health facilities satisfy the conditions for safe injections in terms of staff training, availability of sterile injectable equipment and their proper disposal after use and b to assess knowledge and attitudes of healthcare workers in these health care facilities with regard to injection safety. Methodology A descriptive cross-sectional mixed type (qualitative and quantitative survey was carried out from 18th May to 16th June 2012. In-depth interviews with the in-charges were conducted using a semi-structured questionnaire. Observation of the health facilities using a structured observation tool was done. The data were analysed manually by summarizing, tabulating and presenting in various formats. Results The in-charges (eight males, two females who participated in the study ranged in age from 30 to 50 years with a mean age of 37.8 years. Severe infection followed by pain was the most important cause for injection use with injection Gentamicin being most commonly prescribed. New single use (disposable injections and auto-disable syringes were used to inject curative drugs and vaccines respectively. Sufficient safety boxes were also supplied to dispose the used syringe. All health care workers had received full course of Hepatitis B vaccine and were knowledgeable about at least one pathogen transmitted through unsafe injection practices. Injection safety management policy and waste disposal guideline was not available for viewing in any of the facilities. The office staff who disposed the bio-medical wastes did so without taking any safety measures. Moreover, none of these staff had received any formal

Gas injection system in the Tara center cell

International Nuclear Information System (INIS)

Brau, K.; Post, R.S.; Sevillano, E.

1985-11-01

Precise control of the gas fueling is essential to the successful operation of tandem mirror plasmas. Improper choice of fueling location, magnetic geometry, and gas injection rates can prevent potential and thermal barrier formation, as well as reduce the energy confinement time. In designing the new gas injection configuration for the Tara center cell, the following issues were addressed: RF potential barriers, gas leakage, and charge exchange recombination. 2 refs., 6 figs

Coulombic charge ice

Science.gov (United States)

McClarty, P. A.; O'Brien, A.; Pollmann, F.

2014-05-01

We consider a classical model of charges ±q on a pyrochlore lattice in the presence of long-range Coulomb interactions. This model first appeared in the early literature on charge order in magnetite [P. W. Anderson, Phys. Rev. 102, 1008 (1956), 10.1103/PhysRev.102.1008]. In the limit where the interactions become short ranged, the model has a ground state with an extensive entropy and dipolar charge-charge correlations. When long-range interactions are introduced, the exact degeneracy is broken. We study the thermodynamics of the model and show the presence of a correlated charge liquid within a temperature window in which the physics is well described as a liquid of screened charged defects. The structure factor in this phase, which has smeared pinch points at the reciprocal lattice points, may be used to detect charge ice experimentally. In addition, the model exhibits fractionally charged excitations ±q/2 which are shown to interact via a 1/r potential. At lower temperatures, the model exhibits a transition to a long-range ordered phase. We are able to treat the Coulombic charge ice model and the dipolar spin ice model on an equal footing by mapping both to a constrained charge model on the diamond lattice. We find that states of the two ice models are related by a staggering field which is reflected in the energetics of these two models. From this perspective, we can understand the origin of the spin ice and charge ice ground states as coming from a dipolar model on a diamond lattice. We study the properties of charge ice in an external electric field, finding that the correlated liquid is robust to the presence of a field in contrast to the case of spin ice in a magnetic field. Finally, we comment on the transport properties of Coulombic charge ice in the correlated liquid phase.

Study of Charge Carrier Transport in GaN Sensors

Science.gov (United States)

Gaubas, Eugenijus; Ceponis, Tomas; Kuokstis, Edmundas; Meskauskaite, Dovile; Pavlov, Jevgenij; Reklaitis, Ignas

2016-01-01

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. PMID:28773418

Two interesting cases in spatial charge movement

International Nuclear Information System (INIS)

Novellino, R.A.

1983-01-01

The relation between current and voltage in a dielectric under radiation is obtained, assuming only one carrier to be mobile, recombination and injection of the mobile charge from the electrode. For this last boundary condition a constant charge density at the electrode-dielectric interface was chosen. The other problem treated is a generalization of the classic transient problem studied by Many-Rakavy, using the constant charge density boundary condition. Analytic solutions were obtained during the first transit time and computed ones for larger times. Some attention was given to the damped current oscilations approaching the steady state value. (Author) [pt

Charge dividing mechanism in position-sensitive detectors

International Nuclear Information System (INIS)

Radeka, V.; Rehak, P.

1978-01-01

A complete charge-division mechanism, including both the diffusion and the electromagnetic wave propagation on resistive electrodes, is presented. The charge injected into such a transmission line divides between the two ends according to the ratio of resistances and independently of the value of the line resistance, of the propagation mechanism and of the distribution of inductance and capacitance along the line. The shortest charge division time is achieved for Rl = 2π (L/C)/sup 1/2), where R, L, C are resistance, inductance and capacitance per unit length and l is the length of the line

BEAMS3D Neutral Beam Injection Model

Energy Technology Data Exchange (ETDEWEB)

Lazerson, Samuel

2014-04-14

With the advent of applied 3D fi elds in Tokamaks and modern high performance stellarators, a need has arisen to address non-axisymmetric effects on neutral beam heating and fueling. We report on the development of a fully 3D neutral beam injection (NBI) model, BEAMS3D, which addresses this need by coupling 3D equilibria to a guiding center code capable of modeling neutral and charged particle trajectories across the separatrix and into the plasma core. Ionization, neutralization, charge-exchange, viscous velocity reduction, and pitch angle scattering are modeled with the ADAS atomic physics database [1]. Benchmark calculations are presented to validate the collisionless particle orbits, neutral beam injection model, frictional drag, and pitch angle scattering effects. A calculation of neutral beam heating in the NCSX device is performed, highlighting the capability of the code to handle 3D magnetic fields.

Charge density waves in solids

CERN Document Server

Gor'kov, LP

2012-01-01

The latest addition to this series covers a field which is commonly referred to as charge density wave dynamics.The most thoroughly investigated materials are inorganic linear chain compounds with highly anisotropic electronic properties. The volume opens with an examination of their structural properties and the essential features which allow charge density waves to develop.The behaviour of the charge density waves, where interesting phenomena are observed, is treated both from a theoretical and an experimental standpoint. The role of impurities in statics and dynamics is considered and an

Charge exchange cooling in the tandem mirror plasma confinement apparatus

Science.gov (United States)

Logan, B. Grant

1978-01-01

Method and apparatus for cooling a plasma of warm charged species confined in the center mirror cell of the tandem mirror apparatus by injecting cold neutral species of the plasma into at least one mirroring region of the center mirror cell, the cooling due to the loss of warm charged species through charge exchange with the cold neutral species with resulting diffusion of the warm neutral species out of the plasma.

Effect of fiber content on flexural properties of glass fiber-reinforced polyamide-6 prepared by injection molding.

Science.gov (United States)

Nagakura, Manamu; Tanimoto, Yasuhiro; Nishiyama, Norihiro

2017-07-26

The use of non-metal clasp denture (NMCD) materials may seriously affect the remaining tissues because of the low rigidity of NMCD materials such as polyamides. The purpose of this study was to develop a high-rigidity glass fiber-reinforced thermoplastic (GFRTP) composed of E-glass fiber and polyamide-6 for NMCDs using an injection molding. The reinforcing effects of fiber on the flexural properties of GFRTPs were investigated using glass fiber content ranging from 0 to 50 mass%. Three-point bending tests indicated that the flexural strength and elastic modulus of a GFRTP with a fiber content of 50 mass% were 5.4 and 4.7 times higher than those of unreinforced polyamide-6, respectively. The result showed that the physical characteristics of GFRTPs were greatly improved by increasing the fiber content, and the beneficial effects of fiber reinforcement were evident. The findings suggest that the injection-molded GFRTPs are adaptable to NMCDs because of their excellent mechanical properties.

Field characterization of elastic properties across a fault zone reactivated by fluid injection

Science.gov (United States)

Jeanne, Pierre; Guglielmi, Yves; Rutqvist, Jonny; Nussbaum, Christophe; Birkholzer, Jens

2017-08-01

We studied the elastic properties of a fault zone intersecting the Opalinus Clay formation at 300 m depth in the Mont Terri Underground Research Laboratory (Switzerland). Four controlled water injection experiments were performed in borehole straddle intervals set at successive locations across the fault zone. A three-component displacement sensor, which allowed capturing the borehole wall movements during injection, was used to estimate the elastic properties of representative locations across the fault zone, from the host rock to the damage zone to the fault core. Young's moduli were estimated by both an analytical approach and numerical finite difference modeling. Results show a decrease in Young's modulus from the host rock to the damage zone by a factor of 5 and from the damage zone to the fault core by a factor of 2. In the host rock, our results are in reasonable agreement with laboratory data showing a strong elastic anisotropy characterized by the direction of the plane of isotropy parallel to the laminar structure of the shale formation. In the fault zone, strong rotations of the direction of anisotropy can be observed. The plane of isotropy can be oriented either parallel to bedding (when few discontinuities are present), parallel to the direction of the main fracture family intersecting the zone, and possibly oriented parallel or perpendicular to the fractures critically oriented for shear reactivation (when repeated past rupture along this plane has created a zone).

Charge and excitation dynamics in semiconducting polymer layers doped with emitters and charge carrier traps; Ladungstraeger- und Anregungsdynamik in halbleitenden Polymerschichten mit eingemischten Emittern und Ladungstraegerfallen

Energy Technology Data Exchange (ETDEWEB)

Jaiser, F

2006-06-15

Light-emitting diodes generate light from the recombination of injected charge carriers. This can be obtained in inorganic materials. Here, it is necessary to produce highly ordered crystalline structures that determine the properties of the device. Another possibility is the utilization of organic molecules and polymers. Based on the versatile organic chemistry, it is possible to tune the properties of the semiconducting polymers already during synthesis. In addition, semiconducting polymers are mechanically flexible. Thus, it is possible to construct flexible, large-area light sources and displays. The first light-emitting diode using a polymer emitter was presented in 1990. Since then, this field of research has grown rapidly up to the point where first products are commercially available. It has become clear that the properties of polymer light-emitting diodes such as color and efficiency can be improved by incorporating multiple components inside the active layer. At the same time, this gives rise to new interactions between these components. While components are often added either to improve the charge transport or to change the emission, it has to made sure that other processes are not influenced in a negative manner. This work investigates some of these interactions and describes them with simple physical models. First, blue light-emitting diodes based on polyfluorene are analyzed. This polymer is an efficient emitter, but it is susceptible to the formation of chemical defects that can not be suppressed completely. These defects form electron traps, but their effect can be compensated by the addition of hole traps. The underlying process, namely the changed charge carrier balance, is explained. In the following, blend systems with dendronized emitters that form electron traps are investigated. The different influence of the insulating shell on the charge and energy transfer between polymer host and the emissive core of the dendrimers is examined. In the

Improving charge transport property and energy transfer with carbon quantum dots in inverted polymer solar cells

International Nuclear Information System (INIS)

Liu, Chunyu; Chang, Kaiwen; Guo, Wenbin; Li, Hao; Shen, Liang; Chen, Weiyou; Yan, Dawei

2014-01-01

Carbon quantum dots (Cdots) are synthesized by a simple method and introduced into active layer of polymer solar cells (PSCs). The performance of doped devices was apparently improved, and the highest power conversion efficiency of 7.05% was obtained, corresponding to a 28.2% enhancement compared with that of the contrast device. The charge transport properties, resistance, impedance, and transient absorption spectrum are systematically investigated to explore how the Cdots affect on PSCs performance. This study reveals the importance of Cdots in enhancing the efficiency of PSCs and gives insight into the mechanism of charge transport improvement.

Charging for hospital pharmaceutical services: flat free based on the medication record.

Science.gov (United States)

Wyatt, B K

1979-03-01

A 200-bed hospital's change in pricing drug products from a cost-plus-fee system to a flat fee per dose based on the medication administration record (MAR) is described. With the flat-fee system, drug charges are not recorded when the drug is dispensed by the pharmacy; data for charging doses are obtained directly from the MAR forms generated by the nursing staff. Charges are 55 cents per oral or suppository dose and $3.00 per injection dose. Drugs administered intravenously, topical drugs, injections costing more than $10.00 per dose, and miscellaneous nondrug items are still charged on a cost-plus-fee basis. Man-hours are saved in the pharmacy department because of the elimination of the pricing function and maintenance of price lists. The need for nursing staff to charge for any doses administered from emergency or Schedule II floor-stock supplies is eliminated. The workload for business office personnel is reduced because the number of individual charges is less than with the cost-plus charging system. The system is accepted by patients and third-party payers and has made a complete unit dose drug distribution system possible at lower cost.

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.

The influence of particle size distribution on the properties of metal-injection-moulded 17-4 PH stainless steel

CSIR Research Space (South Africa)

Seerane, Mandy

2016-10-01

Full Text Available Metal injection moulding (MIM) is a near-net-shaping powder metallurgy technique suitable for the cost-effective mass production of small and complex components. In this paper, the effects of the metal powder particle size on the final properties...

A tracking code for injection and acceleration studies in synchrotrons

International Nuclear Information System (INIS)

Lessner, E.; Symon, K.; Univ. of Wisconsin, Madison, WI

1996-01-01

CAPTURE-SPC is a Monte-Carlo-based tracking program that simulates the injection and acceleration processes in proton synchrotrons. The time evolution of a distribution of charged particles is implemented by a symplectic, second-order-accurate integration algorithm. The recurrence relations follow a time-stepping leap--frog method. The time-step can be varied optionally to reduce computer time. Space-charge forces are calculated by binning the phase-projected particle distribution. The statistical fluctuations introduced by the binning process are reduced by presmoothing the data by the cloud-in-cell method and by filtering. Both the bin size and amount of filtering can be varied during the acceleration cycle so that the bunch fine structure is retained while the short wavelength noise is attenuated. The initial coordinates of each macro particle together with its time of injection are retained throughout the calculations. This information is useful in determining low-loss injection schemes

Charge-charge correlations and the detection of weak vector bosons by hadronic jets in proton-antiproton and proton-proton collisions at collider energies

International Nuclear Information System (INIS)

Ranft, J.; Ritter, S.

1980-07-01

The charge properties of quark jets are studied within a chain decay model for quark jet fragmentation. Using the charge properties of quark jets, charge-charge two-jet cross sections and correlations are defined. In proton-antiproton collisions these correlations show significant structure due to the weak vector bosons W +- and Z 0 . (author)

Droop-Control-Based State-of-Charge Balancing Method for Charging and Discharging Process in Autonomous DC Microgrids

DEFF Research Database (Denmark)

Lu, Xiaonan; Sun, Kai; Guerrero, Josep M.

2014-01-01

in the discharging process. Meanwhile, the ESU with lower SoC absorbs more power in the charging process and delivers less power in the discharging process. Eventually, the SoC and injected/output power in each ESU are equalized. The exponent n for SoC is employed to regulate the balancing speed of the So......C and injected/output power. It is demonstrated that with higher exponent n, the balancing speed is higher. Simulation model comprised of three ESUs is implemented by using MATLAB/Simulink. The proposed method is verified by the simulation results....

Tail state-assisted charge injection and recombination at the electron-collecting interface of P3HT:PCBM bulk-heterojunction polymer solar cells

Energy Technology Data Exchange (ETDEWEB)

Wang, He [Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544 (United States); Department of Electrical Engineering, Princeton University, Princeton, NJ 08544 (United States); Shah, Manas [Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Ganesan, Venkat [Department of Chemical Engineering, University of Texas at Austin, Austin, TX 78712 (United States); Chabinyc, Michael L. [Materials Department, University of California Santa Barbara, CA 93106 (United States); Loo, Yueh-Lin [Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544 (United States)

2012-12-15

The systematic insertion of thin films of P3HT and PCBM at the electron- and hole-collecting interfaces, respectively, in bulk-heterojunction polymer solar cells results in different extents of reduction in device characteristics, with the insertion of P3HT at the electron-collecting interface being less disruptive to the output currents compared to the insertion of PCBM at the hole-collecting interface. This asymmetry is attributed to differences in the tail state-assisted charge injection and recombination at the active layer-electrode interfaces. P3HT exhibits a higher density of tail states compared to PCBM; holes in these tail states can thus easily recombine with electrons at the electron-collection interface during device operation. This process is subsequently compensated by the injection of holes from the cathode into these tail states, which collectively enables net current flow through the polymer solar cell. The study presented herein thus provides a plausible explanation for why preferential segregation of P3HT to the cathode interface is inconsequential to device characteristics in P3HT:PCBM bulk-heterojunction solar cells. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Examination of injection moulded thermoplastic maize starch

Directory of Open Access Journals (Sweden)

2007-12-01

Full Text Available This paper focuses on the effect of the different injection moulding parameters and storing methods on injection moulded thermoplastic maize starch (TPS. The glycerol and water plasticized starch was processed in a twin screw extruder and then with an injection moulding machine to produce TPS dumbbell specimens. Different injection moulding set-ups and storing conditions were used to analyse the effects on the properties of thermoplastic starch. Investigated parameters were injection moulding pressure, holding pressure, and for the storage: storage at 50% relative humidity, and under ambient conditions. After processing the mechanical and shrinkage properties of the manufactured TPS were determined as a function of the ageing time. While conditioning, the characteristics of the TPS changed from a soft material to a rigid material. Although this main behaviour remained, the different injection moulding parameters changed the characteristics of TPS. Scanning electron microscope observations revealed the changes in the material on ageing.

Effect of boron compounds on physical, mechanical, and fire properties of injection molded wood plastic composites

Science.gov (United States)

Nadir Ayrilmis; Turgay Akbulut; Turker Dundar; Robert H. White; Fatih Mengeloglu; Zeki Candan; Umit Buyuksari; Erkan Avci

2011-01-01

Physical, mechanical, and fire properties of the injection-molded wood flour/polypropylene composites (WPCs) incorporated with different levels of boron compounds, borax/boric acid (BX/BA) (0.5:0.5 wt %) and zinc borate (ZB) (4, 8, or 12 wt %) were investigated. The effect of the coupling agent loading (2, 4, or 6 wt %), maleic anhydride-grafted PP (MAPP), on the...

Field penetration induced charge redistribution effects on the field emission properties of carbon nanotubes - a first-principle study

International Nuclear Information System (INIS)

Chen, C.-W.; Lee, M.-H.; Clark, S.J.

2004-01-01

The effect of field penetration induced charge redistribution on the field emission properties of carbon nanotubes (CNTs) have been studied by the first-principle calculations. It is found that the carbon nanotube becomes polarized under external electric field leading to a charge redistribution. The resulting band bending induced by field penetration into the nanotube tip surface can further reduce the effective workfunction of the carbon nanotubes. The magnitude of the redistributed charge ΔQ is found to be nearly linear to the applied external field strength. In addition, we found that the capped (9, 0) zigzag nanotube demonstrates better field emission properties than the capped (5, 5) armchair nanotube due to the fact that the charge redistribution of π electrons along the zigzag-like tube axis is easier than for the armchair-like tube. The density of states (DOS) of the capped region of the nanotube is found to be enhanced with a value 30% higher than that of the sidewall part for the capped (5, 5) nanotube and 40% for the capped (9, 0) nanotube under an electric field of 0.33 V/A. Such enhancements of the DOS at the carbon nanotube tip show that electrons near the Fermi level will emit more easily due to the change of the surface band structure resulting from the field penetration in a high field

Comparison of mechanical properties for polyamide 12 composite-based biomaterials fabricated by fused filament fabrication and injection molding

Science.gov (United States)

Rahim, Tuan Noraihan Azila Tuan; Abdullah, Abdul Manaf; Akil, Hazizan Md; Mohamad, Dasmawati

2016-12-01

The emergence of 3D printing technology known as fused filament fabrication (FFF) has offered the possibility of producing an anatomically accurate, patient specific implant with more affordable prices. The only weakness of this technology is related to incompatibility and lack of properties of current material to be applied in biomedical. Therefore, this study aims to develop a new, polymer composite-based biomaterial that exhibits a high processability using FFF technique, strong enough and shows acceptable biocompatibility, and safe for biomedical use. Polyamide 12 (PA12), which meets all these requirements was incorporated with two bioceramic fillers, zirconia and hydroxyapatite in order to improve the mechanical and bioactivity properties. The obtained mechanical properties were compared with injection-molded specimens and also a commercial biomedical product, HAPEXTM which is composed of hydroxyapatite and polyethylene. The yield strength and modulus of the PA12 composites increased steadily with increasing filler loading. Although the strength of printed PA12 composites were reduced compared with injection molded specimen, but still higher than HAPEXTM material. The higher surface roughness obtained by printed PA12 was expected to enhance the cell adhesion and provide better implant fixation.

Effects of pilot injection timing and EGR on a modern V6 common rail direct injection diesel engine

Science.gov (United States)

Rosli Abdullah, Nik; Mamat, Rizalman; Wyszynski, Miroslaw L.; Tsolakis, Anthanasios; Xu, Hongming

2013-12-01

Nitric oxide and smoke emissions in diesel engine can be controlled by optimising the air/fuel mixture. Early injection produces premixed charge resulted in simultaneous NOx and smoke emissions reduction. However, there could be an increase in hydrocarbons and CO emissions due to fuel impinged to the cylinder wall. The focus of the present work is to investigate the effects of a variation of pilot injection timing with EGR to NOx and smoke level on a modern V6 common rail direct injection. This study is carried out at two different engine load conditions of 30 Nm and 55 Nm, at constant engine speed of 2000 rpm. The results show that the early pilot injection timing contributed to the lower smoke level and higher NOx emissions. The higher level of NOx is due to higher combustion temperatures resulting from the complete combustion. Meanwhile, the lower smoke level is due to complete fuel combustion and soot oxidation. The early pilot injection timing produces an intermediate main ignition delay which also contributed to complete combustion. The formation of smoke is higher at a high engine load compared with low engine load due to the higher amount of fuel being injected.

Effects of injection angles on combustion processes using multiple injection strategies in an HSDI diesel engine

Energy Technology Data Exchange (ETDEWEB)

Tiegang Fang; Robert E. Coverdill; Chia-fon F. Lee; Robert A. White [North Carolina State University, Raleigh, NC (United States). Department of Mechanical and Aerospace Engineering

2008-11-15

Effects of injection angles and injection pressure on the combustion processes employing multiple injection strategies in a high-speed direct-injection (HSDI) diesel engine are presented in this work. Whole-cycle combustion and liquid spray evolution processes were visualized using a high-speed video camera. NOx emissions were measured in the exhaust pipe. Different heat release patterns are seen for two different injectors with a 70-degree tip and a 150-degree tip. No evidence of fuel-wall impingement is found for the first injection of the 150-degree tip, but for the 70-degree tip, some fuel impinges on the bowl wall and a fuel film is formed. For the second injection, a large amount of fuel deposition is observed for the 70-degree tip. Weak flame is seen for the first injection of the 150-degree tip while two sorts of flames are seen for the first injection of the 70-degree tip including an early weak flame and a late luminous film combustion flame. Ignition occurs near the spray tip in the vicinity of the bowl wall for the second injection events of the 150-degree tip, however, it is near the injector tip in the central region of the bowl for the 70-degree tip. The flame is more homogeneous for the 150-degree tip with higher injection pressure with little soot formation similar to a premixed-charge-compression-ignition (PCCI) combustion. For other cases, liquid fuel is injected into flames showing diffusion flame combustion. More soot luminosity is seen for the 70-degree tip due to significant fuel film deposition on the piston wall with fuel film combustion for both injection events. Lower NOx emissions were obtained for the narrow-angle injector due to the rich air-fuel mixture near the bowl wall during the combustion process. 30 refs., 11 figs., 3 tabs.

Impact of speciation on the electron charge transfer properties of nanodiamond drug carriers.

Science.gov (United States)

Sun, Baichuan; Barnard, Amanda S

2016-08-07

Unpassivated diamond nanoparticles (bucky-diamonds) exhibit a unique surface reconstruction involving graphitization of certain crystal facets, giving rise to hybrid core-shell particles containing both aromatic and aliphatic carbon. Considerable effort is directed toward eliminating the aromatic shell, but persistent graphitization of subsequent subsurface-layers makes perdurable purification a challenge. In this study we use some simple statistical methods, in combination with electronic structure simulations, to predict the impact of different fractions of aromatic and aliphatic carbon on the charge transfer properties of the ensembles of bucky-diamonds. By predicting quality factors for a variety of cases, we find that perfect purification is not necessary to preserve selectivity, and there is a clear motivation for purifying samples to improve the sensitivity of charge transfer reactions. This may prove useful in designing drug delivery systems where the release of (selected) drugs needs to be sensitive to specific conditions at the point of delivery.

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.

Influence of sorbitol on mechanical and physico-chemical properties of soy protein-based bioplastics processed by injection molding

Directory of Open Access Journals (Sweden)

Manuel Felix

Full Text Available Abstract Soy Protein Isolate (SPI has been evaluated as useful candidate for the development of protein-based bioplastic materials processed by injection molding. The influence of sorbitol (SB as plasticizer in mechanical properties and water uptake capacity was evaluated in SPI-based bioplastics. A mixing rheometer that allows monitoring torque and temperature during mixing and a small-scale-plunger-type injection molding machine were used to obtain SPI/Plasticizer blends and SPI-based bioplastics, respectively. Dynamic measurements were carried out to obtain mechanical spectra of different bioplastics. Moreover, the mechanical characterization was supplemented with uniaxial tensile tests. Additionally, the influence of SB in water uptake capacity was also evaluated. The introduction of SB leads to increase the rigidity of bioplastics as well as the water uptake capacity after 24h, however it involves a decrease in strain at break. Final bioplastics are plastic materials with both adequate properties for the substitution of conventional petroleum plastics and high biodegradability.

Photovoltaic Properties in Interpenetrating Heterojunction Organic Solar Cells Utilizing MoO3 and ZnO Charge Transport Buffer Layers

Science.gov (United States)

Hori, Tetsuro; Moritou, Hiroki; Fukuoka, Naoki; Sakamoto, Junki; Fujii, Akihiko; Ozaki, Masanori

2010-01-01

Organic thin-film solar cells with a conducting polymer (CP)/fullerene (C60) interpenetrating heterojunction structure, fabricated by spin-coating a CP onto a C60 deposit thin film, have been investigated and demonstrated to have high efficiency. The photovoltaic properties of solar cells with a structure of indium-tin-oxide/C60/poly(3-hexylthiophene) (PAT6)/Au have been improved by the insertion of molybdenum trioxide (VI) (MoO3) and zinc oxide charge transport buffer layers. The enhanced photovoltaic properties have been discussed, taking into consideration the ground-state charge transfer between PAT6 and MoO3 by measurement of the differential absorption spectra and the suppressed contact resistance at the interface between the organic and buffer layers. PMID:28883360

Photovoltaic Properties in Interpenetrating Heterojunction Organic Solar Cells Utilizing MoO3 and ZnO Charge Transport Buffer Layers

Directory of Open Access Journals (Sweden)

Tetsuro Hori

2010-11-01

Full Text Available Organic thin-film solar cells with a conducting polymer (CP/fullerene (C60 interpenetrating heterojunction structure, fabricated by spin-coating a CP onto a C60 deposit thin film, have been investigated and demonstrated to have high efficiency. The photovoltaic properties of solar cells with a structure of indium-tin-oxide/C60/ poly(3-hexylthiophene (PAT6/Au have been improved by the insertion of molybdenum trioxide (VI (MoO3 and zinc oxide charge transport buffer layers. The enhanced photovoltaic properties have been discussed, taking into consideration the ground-state charge transfer between PAT6 and MoO3 by measurement of the differential absorption spectra and the suppressed contact resistance at the interface between the organic and buffer layers.

Space-charge calculations in synchrotrons

Energy Technology Data Exchange (ETDEWEB)

Machida, S.

1993-05-01

One obvious bottleneck of achieving high luminosity in hadron colliders, such as the Superconducting Super Collider (SSC), is the beam emittance growth, due to space-charge effects in low energy injector synchrotrons. Although space-charge effects have been recognized since the alternating-gradient synchrotron was invented, and the Laslett tune shift usually calculated to quantify these effects, our understanding of the effects is limited, especially when the Laslett tune shift becomes a large fraction of the integer. Using the Simpsons tracking code, which we developed to study emittance preservation issues in proton synchrotrons, we investigated space-charge effects in the SSC Low Energy Booster (LEB). We observed detailed dependence on parameters such as beam intensity, initial emittance, injection energy, lattice function, and longitudinal motion. A summary of those findings, as well as the tracking technique we developed for the study, are presented.

Top Quark Pair Properties - Spin Correlation, Charge Asymmetry, and Complex Final States - at ATLAS

Directory of Open Access Journals (Sweden)

Brost Elizabeth

2014-04-01

Full Text Available We present measurements of top quark pair properties performed with the ATLAS detector at the Large Hadron Collider in proton-proton collisions at a center-of-mass energy of √s = 7 TeV. The latest measurements of spin correlation and charge asymmetry in tt¯$t\\overline t $ events, as well as measurements of the cross section for tt¯$t\\overline t $ production in association with vector bosons, are presented.

Diagnosing the PEP-II Injection System

Energy Technology Data Exchange (ETDEWEB)

Decker, F.-J.; Donald, M.H.; Iverson, R.H.; Kulikov, A.; Pappas, G.C.; Weaver, M.; /SLAC

2005-05-09

The injection of beam into the PEP-II B-Factory, especially into the High Energy Ring (HER) has some challenges. A high background level in the BaBar detector has for a while inhibited us from trickling charge into the HER similar to the Low Energy Ring (LER). Analyzing the injection system has revealed many issues which could be improved. The injection bump between two kickers was not closed, mainly because the phase advance wasn't exactly 180{sup o} and the two kicker strengths were not balanced. Additionally we found reflections which kick the stored beam after the main kick and cause the average luminosity to drop about 3% for a 10 Hz injection rate. The strength of the overall kick is nearly twice as high as the design, indicating a much bigger effective septum thickness. Compared with single beam the background is worse when the HER beam is colliding with the LER beam. This hints that the beam-beam force and the observed vertical blow-up in the HER pushes the beam and especially the injected beam further out to the edge of the dynamic aperture or beyond.

Diagnosing the PEP-II Injection System

International Nuclear Information System (INIS)

Decker, F.-J.; Donald, M.H.; Iverson, R.H.; Kulikov, A.; Pappas, G.C.; Weaver, M.; SLAC

2005-01-01

The injection of beam into the PEP-II B-Factory, especially into the High Energy Ring (HER) has some challenges. A high background level in the BaBar detector has for a while inhibited us from trickling charge into the HER similar to the Low Energy Ring (LER). Analyzing the injection system has revealed many issues which could be improved. The injection bump between two kickers was not closed, mainly because the phase advance wasn't exactly 180 o and the two kicker strengths were not balanced. Additionally we found reflections which kick the stored beam after the main kick and cause the average luminosity to drop about 3% for a 10 Hz injection rate. The strength of the overall kick is nearly twice as high as the design, indicating a much bigger effective septum thickness. Compared with single beam the background is worse when the HER beam is colliding with the LER beam. This hints that the beam-beam force and the observed vertical blow-up in the HER pushes the beam and especially the injected beam further out to the edge of the dynamic aperture or beyond

Non-local electrical spin injection and detection in germanium at room temperature

Science.gov (United States)

Rortais, F.; Vergnaud, C.; Marty, A.; Vila, L.; Attané, J.-P.; Widiez, J.; Zucchetti, C.; Bottegoni, F.; Jaffrès, H.; George, J.-M.; Jamet, M.

2017-10-01

Non-local carrier injection/detection schemes lie at the very foundation of information manipulation in integrated systems. This paradigm consists in controlling with an external signal the channel where charge carriers flow between a "source" and a well separated "drain." The next generation electronics may operate on the spin of carriers in addition to their charge and germanium appears as the best hosting material to develop such a platform for its compatibility with mainstream silicon technology and the predicted long electron spin lifetime at room temperature. In this letter, we demonstrate injection of pure spin currents (i.e., with no associated transport of electric charges) in germanium, combined with non-local spin detection at 10 K and room temperature. For this purpose, we used a lateral spin valve with epitaxially grown magnetic tunnel junctions as spin injector and spin detector. The non-local magnetoresistance signal is clearly visible and reaches ≈15 mΩ at room temperature. The electron spin lifetime and diffusion length are 500 ps and 1 μm, respectively, the spin injection efficiency being as high as 27%. This result paves the way for the realization of full germanium spintronic devices at room temperature.

Magnetic properties changes of MnAs thin films irradiated with highly charged ions

OpenAIRE

Trassinelli , Martino; Gafton , V.; Eddrief , Mahmoud; Etgens , Victor H.; Hidki , S.; Lacaze , Emmanuelle; Lamour , Emily; Luo , X.; Marangolo , Massimiliano; Merot , Jacques; Prigent , Christophe; Reuschl , Regina; Rozet , Jean-Pierre; Steydli , S.; Vernhet , Dominique

2013-01-01

International audience; We present the first investigation on the effect of highly charged ion bombardment on a manganese arsenide thin film. The MnAs films, 150~nm thick, are irradiated with 90 keV Ne$^{9+}$ ions with a dose varying from $1.6\\times10^{12}$ to $1.6\\times10^{15}$~ions/cm$^2$. The structural and magnetic properties of the film after irradiation are investigated using different techniques, namely, X-ray diffraction, magneto-optic Kerr effect and magnetic force microscope. Prelim...

Interfacial charge separation and photovoltaic efficiency in Fe(ii)-carbene sensitized solar cells.

Science.gov (United States)

Pastore, Mariachiara; Duchanois, Thibaut; Liu, Li; Monari, Antonio; Assfeld, Xavier; Haacke, Stefan; Gros, Philippe C

2016-10-12

The first combined theoretical and photovoltaic characterization of both homoleptic and heteroleptic Fe(ii)-carbene sensitized photoanodes in working dye sensitized solar cells (DSSCs) has been performed. Three new heteroleptic Fe(ii)-NHC dye sensitizers have been synthesized, characterized and tested. Despite an improved interfacial charge separation in comparison to the homoleptic compounds, the heteroleptic complexes did not show boosted photovoltaic performances. The ab initio quantitative analysis of the interfacial electron and hole transfers and the measured photovoltaic data clearly evidenced fast recombination reactions for heteroleptics, even associated with un unfavorable directional electron flow, and hence slower injection rates, in the case of homoleptics. Notably, quantum mechanics calculations revealed that deprotonation of the not anchored carboxylic function in the homoleptic complex can effectively accelerate the electron injection rate and completely suppress the electron recombination to the oxidized dye. This result suggests that introduction of strong electron-donating substituents on the not-anchored carbene ligand in heteroleptic complexes, in such a way of mimicking the electronic effects of the carboxylate functionality, should yield markedly improved interfacial charge generation properties. The present results, providing for the first time a detailed understanding of the interfacial electron transfers and photovoltaic characterization in Fe(ii)-carbene sensitized solar cells, open the way to a rational molecular engineering of efficient iron-based dyes for photoelectrochemical applications.

Anisotropic charge transport in large single crystals of π-conjugated organic molecules.

Science.gov (United States)

Hourani, Wael; Rahimi, Khosrow; Botiz, Ioan; Koch, Felix Peter Vinzenz; Reiter, Günter; Lienerth, Peter; Heiser, Thomas; Bubendorff, Jean-Luc; Simon, Laurent

2014-05-07

The electronic properties of organic semiconductors depend strongly on the nature of the molecules, their conjugation and conformation, their mutual distance and the orientation between adjacent molecules. Variations of intramolecular distances and conformation disturb the conjugation and perturb the delocalization of charges. As a result, the mobility considerably decreases compared to that of a covalently well-organized crystal. Here, we present electrical characterization of large single crystals made of the regioregular octamer of 3-hexyl-thiophene (3HT)8 using a conductive-atomic force microscope (C-AFM) in air. We find a large anisotropy in the conduction with charge mobility values depending on the crystallographic orientation of the single crystal. The smaller conduction is in the direction of π-π stacking (along the long axis of the single crystal) with a mobility value in the order of 10(-3) cm(2) V(-1) s(-1), and the larger one is along the molecular axis (in the direction normal to the single crystal surface) with a mobility value in the order of 0.5 cm(2) V(-1) s(-1). The measured current-voltage (I-V) curves showed that along the molecular axis, the current followed an exponential dependence corresponding to an injection mode. In the π-π stacking direction, the current exhibits a space charge limited current (SCLC) behavior, which allows us to estimate the charge carrier mobility.

Influence of Zn injection on corrosion behavior and oxide film characteristics of 304 stainless steel in borated and lithiated high temperature water

International Nuclear Information System (INIS)

Wu, Xinqiang; Liu, Xiahe; Han, En-Hou; Ke, Wei

2012-09-01

Water chemistry of the reactor coolant system plays a major role in maintaining safety and reliability of light water reactor nuclear power plants (NPPs). Zn water chemistry into pressurized water reactors (PWRs) in order to reduce the radiation buildup in primary coolant system has been widely applied, and the reduction effect has been experimentally confirmed. Zn injection can also lessen the corrosion phenomena in high temperature pressurized water by changing oxide films formed on components materials. Both the radiation buildup and material corrosion resistance in PWR coolant system are closely dependent on the oxide films formed. However, the influence of Zn injection on the chemical composition and structure of the oxide films on their protective properties is still a matter of considerable debate. The influence of Zn injection on corrosion inhibition and environmental degradation has not been fully clarified yet. Therefore, the understanding of corrosion behaviour, oxide film characteristics and their protective property is of significance to clarify the environmentally assisted material failure problems in NPPs. In the present work, oxide films formed on nuclear-grade 304 SS exposed to borated and lithiated high temperature water environments at 300 deg. C up to 4000 h with or without 10 ppb Zn injection were investigated ex-situ. Without Zn injection, the oxide films mainly consisted of Fe 3 O 4 and FeCr 2 O 4 . With Zn injection, ZnFe 2 O 4 and ZnCr 2 O 4 were detected in the oxide films at the initial stage of immersion and ZnCr 2 O 4 became dominant after long-term immersion. It was believed that the above Zn-Fe and Zn-Cr spinel oxides were formed by substitution reactions between Zn 2+ and Fe 2+ . At the initial stage of immersion, water chemistry significantly affected the formation of the oxide films. Once a stable oxide film formed, it is rather difficult to change its structure through changing water chemistry. The potential-pH diagrams for Zn

Theoretical studies of optics and charge transport in organic conducting oligomers and polymers: Rational design of improved transparent and conducting polymers

Science.gov (United States)

Hutchison, Geoffrey Rogers

Theoretical studies on a variety of oligo- and polyheterocycles elucidate their optical and charge transport properties, suggesting new, improved transparent conductive polymers. First-principles calculations provide accurate methodologies for predicting both optical band gaps of neutral and cationic oligomers and intrinsic charge transfer rates. Multidimensional analysis reveals important motifs in chemical tailorability of oligoheterocycle optical and charge transport properties. The results suggest new directions for design of novel materials. Using both finite oligomer and infinite polymer calculations, the optical band gaps in polyheterocycles follow a modified particle-in-a-box formalism, scaling approximately as 1/N (where N is the number of monomer units) in short chains, saturating for long chains. Calculations demonstrate that band structure changes upon heteroatom substitution, (e.g., from polythiophene to polypyrrole) derive from heteroatom electron affinity. Further investigation of chemical variability in substituted oligoheterocycles using multidimensional statistics reveals the interplay between heteroatom and substituent in correlations between structure and redox/optical properties of neutral and cationic species. A linear correlation between band gaps of neutral and cationic species upon oxidation of conjugated oligomers, shows redshifts of optical absorption for most species and blueshifts for small band gap species. Interstrand charge-transport studies focus on two contributors to hopping-style charge transfer rates: internal reorganization energy and the electronic coupling matrix element. Statistical analysis of chemical variability of reorganization energies in oligoheterocycles proves the importance of reorganization energy in determining intrinsic charge transfer rates (e.g., charge mobility in unsubstituted oligothiophenes). Computed bandwidths across several oligothiophene crystal packing motifs show similar electron and hole bandwidths

Uncooled EGR as a means of limiting wall-wetting under early direct injection conditions

NARCIS (Netherlands)

Boot, M.D.; Luijten, C.C.M.; Somers, L.M.T.; Eguz, U.; Erp, D.D.T.M. van; Albrecht, A.; Baert, R.S.G.

2009-01-01

Collision of injected fuel spray against the cylinder liner (wall-wetting) is one of the main hurdles that must be overcome in order for early direct injection Premixed Charge Compression Ignition (EDI PCCI) combustion to become a viable alternative for conventional DI diesel combustion. Preferably,

Charge Islands Through Tunneling

Science.gov (United States)

Robinson, Daryl C.

2002-01-01

It has been recently reported that the electrical charge in a semiconductive carbon nanotube is not evenly distributed, but rather it is divided into charge "islands." This paper links the aforementioned phenomenon to tunneling and provides further insight into the higher rate of tunneling processes, which makes tunneling devices attractive. This paper also provides a basis for calculating the charge profile over the length of the tube so that nanoscale devices' conductive properties may be fully exploited.

Characterization of dielectric charging in RF MEMS

NARCIS (Netherlands)

Herfst, R.W.; Huizing, H.G.A.; Steeneken, P.G.; Schmitz, Jurriaan

2005-01-01

Capacitive RF MEMS switches show great promise for use in wireless communication devices such as mobile phones, but the successful application of these switches is hindered by the reliability of the devices: charge injection in the dielectric layer (SiN) can cause irreversible stiction of the moving

Simulation and design of an electron beam ion source charge breeder for the californium rare isotope breeder upgrade

Directory of Open Access Journals (Sweden)

Clayton Dickerson

2013-02-01

Full Text Available An electron beam ion source (EBIS will be constructed and used to charge breed ions from the californium rare isotope breeder upgrade (CARIBU for postacceleration into the Argonne tandem linear accelerator system (ATLAS. Simulations of the EBIS charge breeder performance and the related ion transport systems are reported. Propagation of the electron beam through the EBIS was verified, and the anticipated incident power density within the electron collector was identified. The full normalized acceptance of the charge breeder with a 2 A electron beam, 0.024π  mm mrad for nominal operating parameters, was determined by simulating ion injection into the EBIS. The optics of the ion transport lines were carefully optimized to achieve well-matched ion injection, to minimize emittance growth of the injected and extracted ion beams, and to enable adequate testing of the charge bred ions prior to installation in ATLAS.

Theoretical studies on the effect of benzene and thiophene groups on the charge transport properties of Isoindigo and its derivatives

Science.gov (United States)

Jia, Xu-Bo; Wei, Hui-Ling; Shi, Ya-Ting; Shi, Ya-Rui; Liu, Yu-Fang

2017-12-01

In this work, the charge transport properties of Isoindigo (II) and its derivatives which have the same hexyl chain were theoretically investigated by the Marcus-Hush theory combined with density functional theory (DFT). Here we demonstrate that the changes of benzene and thiophene groups in molecular structure have an important influence on the charge transport properties of organic semiconductor. The benzene rings of II are replaced by thiophenes to form the thienoisoindigo (TII), and the addition of benzene rings to the TII form the benzothienoisoindigo (BTII). The results show that benzene rings and thiophenes change the chemical structure of crystal molecules, which lead to different molecule stacking, thus, the length of hydrogen bond was changed. A shorter intermolecular hydrogen bond lead to tighter molecular stacking, which reduces the center-to-center distance and enhances the ability of charge transfer. At the same time, we theoretically demonstrated that II and BTII are the ambipolar organic semiconductor. BTII has better carrier mobility. The hole mobility far greater than electron mobility in TII, which is p-type organic semiconductor. Among all hopping path, we find that the distance of face-to-face stacking in II is the shortest and the electron-transport electronic coupling Ve is the largest, but II has not a largest anisotropic mobility, because the reorganization energy has a greater influence on the mobility than the electronic coupling. This work is helpful for designing ambipolar organic semiconductor materials with higher charge transport properties by introducing benzene ring and thiophene.

Designing thiophene-based azomethine oligomers with tailored properties: Self-assembly and charge carrier mobility

DEFF Research Database (Denmark)

Kiriy, N.; Bocharova, V.; Kiriy, A.

2004-01-01

This paper describes synthesis and characterization of two thiophene-based azomethines designed to optimize solubility, self-assembly, and charge carrier mobility. We found that incorporation of azomethine and amide moieties in the alpha,omega-position, and hexyl chains in the beta-position of th...... with the mobilities of the best organic semiconductors. All these significant differences in properties of related compounds can be attributed to the hydrogen bonding between QT-amide molecules responsible for the observed self-assembly....

Injection optimization in a heavy-ion synchrotron using genetic algorithms

Energy Technology Data Exchange (ETDEWEB)

Appel, S., E-mail: s.appel@gsi.de [GSI, Helmholtzzentrum für Schwerionenforschung GmbH, Planckstraße 1, 64291 Darmstadt (Germany); Boine-Frankenheim, O. [GSI, Helmholtzzentrum für Schwerionenforschung GmbH, Planckstraße 1, 64291 Darmstadt (Germany); Technische Universität Darmstadt, Schlossgartenstraße 8, 64289 Darmstadt (Germany); Petrov, F. [Technische Universität Darmstadt, Schlossgartenstraße 8, 64289 Darmstadt (Germany)

2017-04-21

The control of the beam loss induced dynamic pressure is one of the most challenging problems for synchrotrons operated with high intensity beams of intermediate charge state ions. This loss-induced vacuum degradation and associated life-time reduction is one of the key intensity limiting factors. Beam loss during Multi-Turn Injection (MTI) can trigger the pressure bump instability. An optimized injection can relax the dynamic vacuum problem, but is also crucial to fill the available machine acceptance. A numerical model has been developed to describe the intensity limitation due to loss-induced vacuum degradation. In order to optimize the multi-turn injection for given initial losses, a genetic algorithm based optimization has been performed. For the SIS18 synchrotron at GSI the optimization resulted in a significant improvement of MTI performance and subsequent transmission for intense beams. A range of suitable injector brilliances for given initial loss could be defined. This information is crucial for the layout of the injector upgrade for FAIR. The effect of transverse space charge force on MTI has been included in the optimization studies.

The artificially injected charged particles as a tool for the measurement of the electric field in the magnetosphere

International Nuclear Information System (INIS)

Pirre, M.

1982-01-01

This chapter discusses two methods of measuring the parallel electric field using artificially injected charged particles. The first method uses electrons to measure the parallel electric field in the vicinity of the spacecraft. The second method uses ions to measure electric potential along the magnetic field lines if the associated parallel electric field is directed downward. The use of electrons for the measurement has many limitations due to the disturbed regions surrounding the spacecraft and to the high level of turbulence which could significantly reduce accuracy. Even if the parallel electric fields are too low to be measured owing to the broadening of the fluxes by turbulence, the electrons can still be used to study the turbulence. It is demonstrated that if parallel electric fields are predominantly directed upward at high altitude, a downward parallel electric field can exist at lower altitude. Lithium ions can be used to maximize the returning fluxes and to increase the probability of detection. Rockets are shown to be more suitable than satellites with regard to measurement

Correction: The effect of recombination under short-circuit conditions on the determination of charge transport properties in nanostructured photoelectrodes.

Science.gov (United States)

Villanueva-Cab, J; Anta, J A; Oskam, G

2016-05-28

Correction for 'The effect of recombination under short-circuit conditions on the determination of charge transport properties in nanostructured photoelectrodes' by J. Villanueva-Cab et al., Phys. Chem. Chem. Phys., 2016, 18, 2303-2308.

Researches on direct injection in internal-combustion engines

Science.gov (United States)

Tuscher, Jean E

1941-01-01

These researches present a solution for reducing the fatigue of the Diesel engine by permitting the preservation of its components and, at the same time, raising its specific horsepower to a par with that of carburetor engines, while maintaining for the Diesel engine its perogative of burning heavy fuel under optimum economical conditions. The feeding of Diesel engines by injection pumps actuated by engine compression achieves the required high speeds of injection readily and permits rigorous control of the combustible charge introduced into each cylinder and of the peak pressure in the resultant cycle.

Dihedral angle control to improve the charge transport properties of conjugated polymers in organic field effect transistors

Science.gov (United States)

Dharmapurikar, Satej S.; Chithiravel, Sundaresan; Mane, Manoj V.; Deshmukh, Gunvant; Krishnamoorthy, Kothandam

2018-03-01

Diketopyrrolopyrrole (DPP) and i-Indigo (i-Ind) are two monomers that are widely explored as active materials in organic field effect transistor and solar cells. These two molecules showed impressive charge carrier mobility due to better packing that are facilitated by quadrupoles. We hypothesized that the copolymers of these monomers would also exhibit high charge carrier mobility. However, we envisioned that the dihedral angle at the connecting point between the monomers will play a crucial role in packing as well as charge transport. To understand the impact of dihedral angle on charge transport, we synthesized three copolymers, wherein the DPP was sandwiched between benzenes, thiophenes and furans. The copolymer of i-Indigo and furan comprising DPP showed a band gap of 1.4 eV with a very high dihedral angle of 179°. The polymer was found to pack better and the coherence length was found to be 112 Å. The hole carrier mobility of these polymer was found to be highest among the synthesized polymer i.e. 0.01 cm2/vs. The copolymer comprising benzene did not transport hole and electrons. The dihedral angle at the connecting point between i and Indigo and benzene DPP was 143 Å, which the packing and consequently charge transport properties.

Space Charge Effects and Advanced Modelling for CERN Low Energy Machines

CERN Document Server

AUTHOR|(CDS)2088716; Rumolo, Giovanni

The strong space charge regime of future operation of CERN’s circular particle accelerators is investigated and mitigation strategies are developed in the framework of the present thesis. The intensity upgrade of the injector chain of Large Hadron Collider (LHC) prepares the particle accelerators to meet the requirements of the High-Luminosity LHC project. Producing the specified characteristics of the future LHC beams imperatively relies on injecting brighter bunches into the Proton Synchrotron Booster (PSB), the downstream Proton Synchrotron (PS) and eventually the Super Proton Synchrotron (SPS). The increased brightness, i.e. bunch intensity per transverse emittance, entails stronger beam self-fields which can lead to harmful interaction with betatron resonances. Possible beam emittance growth and losses as a consequence thereof threaten to degrade the beam brightness. These space charge effects are partly mitigated by the upgrade of the PSB and PS injection energies. Nevertheless, the space charge tune ...

Theoretical studies on the electronic structures and spectral properties of a series of bis-cyclometalated iridium(III) complexes using density functional theory

Energy Technology Data Exchange (ETDEWEB)

Han, Deming [International Joint Research Center for Nanophotonics and Biophotonics, School of Life Science and Technology, Changchun University of Science and Technology, Changchun 130022 (China); Zhang, Gang [State Key Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, Jilin University, Changchun 130023 (China); Cai, Hongxing; Zhang, Xihe [International Joint Research Center for Nanophotonics and Biophotonics, School of Science, Changchun University of Science and Technology, Changchun 130022 (China); Zhao, Lihui, E-mail: zhaolihui@yahoo.com [International Joint Research Center for Nanophotonics and Biophotonics, School of Life Science and Technology, Changchun University of Science and Technology, Changchun 130022 (China)

2013-06-15

We report a quantum-chemistry study of electronic structures and spectral properties of four Ir(III) complexes Ir[2-(2,4-di-X-phenyl)pyridine]{sub 2}(picolinate), where X=–CH{sub 3} (1), –H (2), –CN (3), –NO{sub 2} (4). The absorption and emission spectra were calculated based on the optimized ground state and excited state geometries, respectively, by means of the time-dependent density functional theory (TDDFT). The effect from the electron-withdrawing and electron-donating substituents on charge injection, transport, absorption, and phosphorescent properties has been investigated. The absorption and emission properties can be altered by the different electron-withdrawing and electron-donating groups. Besides, ionization potential (IP), electron affinities (EA) and reorganization energy (λ{sub hole/electron}) were obtained to evaluate the charge transfer and balance properties between hole and electron. The calculated results show that the different substitute groups affect the charge transfer rate and balance. It can be anticipated that the complexes 3 and 4 have good charge transport rates and balance between the hole and electron. -- Highlights: ► Four Ir(III) complexes have been theoretically investigated. ► The different substituents affect the charge transfer rate and balance. ► We design two candidate materials for OLEDs.

Theoretical studies on the electronic structures and spectral properties of a series of bis-cyclometalated iridium(III) complexes using density functional theory

International Nuclear Information System (INIS)

Han, Deming; Zhang, Gang; Cai, Hongxing; Zhang, Xihe; Zhao, Lihui

2013-01-01

We report a quantum-chemistry study of electronic structures and spectral properties of four Ir(III) complexes Ir[2-(2,4-di-X-phenyl)pyridine] 2 (picolinate), where X=–CH 3 (1), –H (2), –CN (3), –NO 2 (4). The absorption and emission spectra were calculated based on the optimized ground state and excited state geometries, respectively, by means of the time-dependent density functional theory (TDDFT). The effect from the electron-withdrawing and electron-donating substituents on charge injection, transport, absorption, and phosphorescent properties has been investigated. The absorption and emission properties can be altered by the different electron-withdrawing and electron-donating groups. Besides, ionization potential (IP), electron affinities (EA) and reorganization energy (λ hole/electron ) were obtained to evaluate the charge transfer and balance properties between hole and electron. The calculated results show that the different substitute groups affect the charge transfer rate and balance. It can be anticipated that the complexes 3 and 4 have good charge transport rates and balance between the hole and electron. -- Highlights: ► Four Ir(III) complexes have been theoretically investigated. ► The different substituents affect the charge transfer rate and balance. ► We design two candidate materials for OLEDs

A hybrid charged-particle guide for studying (n, charged particle) reactions

International Nuclear Information System (INIS)

Haight, R.C.; White, R.M.; Zinkle, S.J.

1983-01-01

Charged-particle transport systems consisting of magnetic quadrupole lenses have been employed in recent years in the study of (n, charged particle) reactions. A new transport system was completed at the laboratory that is based both on magnetic lenses as well as electrostatic fields. The magnetic focusing of the charged-particle guide is provided by six magnetic quadrupole lenses arranged in a CDCCDC sequence (in the vertical plane). The electrostatic field is produced by a wire at high voltage which stretches the length of the guide and is physically at the centre of the magnetic axis. The magnetic lenses are used for charged particles above 5 MeV; the electrostatic guide is used for lower energies. This hybrid system possesses the excellent focusing and background rejection properties of other magnetic systems. For low energy charged-particles, the electrostatic transport avoids the narrow band-passes in charged-particle energy which are a problem with purely magnetic transport systems. This system is installed at the LLNL Cyclograaff facility for the study of (n, charged particle) reactions at neutron energies up to 35 MeV. (Auth.)

Injection system for the PEP II asymmetric B Factory at SLAC

International Nuclear Information System (INIS)

Fieguth, T.; Bloom, E.; Bulos, F.; Davies-White, W.; Donald, M.; Fairfield, K.; Godfrey, G.; Holtzapple, R.; Ronan, M.; Zisman, M.

1992-01-01

The asymmetric energy B Factory proposed as an upgrade of PEP at Stanford Linear Accelerator Center will require a highly reliable and efficient injection system. The conceptual design has shown the feasibility of extracting 9 GeV electrons and 3.1 GeV positrons from the existing linac and injecting equal charges into 1658 buckets in each of the two rings of the collider. An injection study group has continued the development and study of this proposal and has generated workable designs for many related systems and subsystems. (author) 3 refs.; 4 figs.; 2 tabs

Dramatic changes in muscle contractile and structural properties after 2 botulinum toxin injections.

Science.gov (United States)

Minamoto, Viviane B; Suzuki, Kentaro P; Bremner, Shannon N; Lieber, Richard L; Ward, Samuel R

2015-10-01

Botulinum toxin is frequently administered serially to maintain therapeutic muscle paralysis, but the effect of repeated doses on muscle function are largely unknown. This study characterized the muscle response to 2 onabotulinum toxin (BoNT) injections separated by 3 months. Animal subjects received a single toxin injection (n = 8), 2 BoNT injections separated by 3 months (n = 14), or 1 BoNT and 1 saline injection separated by 3 months (n = 8). The functional effect of 2 serial injections was exponentially greater than the effect of a single injection. While both groups treated with a single BoNT injection had decreased torque in the injected leg by approximately 50% relative to contralateral legs, the double BoNT injected group had decreased torque by over 95% relative to the preinjection level. Both single and double BoNT injections produced clear signs of fiber-type grouping. These experiments demonstrate a disproportionately greater effect of repeated BoNT injections. © 2015 Wiley Periodicals, Inc.

Fast and efficient charge breeding of the Californium rare isotope breeder upgrade electron beam ion source

International Nuclear Information System (INIS)

Ostroumov, P. N.; Barcikowski, A.; Dickerson, C. A.; Perry, A.; Sharamentov, S. I.; Vondrasek, R. C.; Zinkann, G. P.; Pikin, A. I.

2015-01-01

The Electron Beam Ion Source (EBIS), developed to breed Californium Rare Isotope Breeder Upgrade (CARIBU) radioactive beams at Argonne Tandem Linac Accelerator System (ATLAS), is being tested off-line. A unique property of the EBIS is a combination of short breeding times, high repetition rates, and a large acceptance. Overall, we have implemented many innovative features during the design and construction of the CARIBU EBIS as compared to the existing EBIS breeders. The off-line charge breeding tests are being performed using a surface ionization source that produces singly charged cesium ions. The main goal of the off-line commissioning is to demonstrate stable operation of the EBIS at a 10 Hz repetition rate and a breeding efficiency into single charge state higher than 15%. These goals have been successfully achieved and exceeded. We have measured (20% ± 0.7%) breeding efficiency into the single charge state of 28+ cesium ions with the breeding time of 28 ms. In general, the current CARIBU EBIS operational parameters can provide charge breeding of any ions in the full mass range of periodic table with high efficiency, short breeding times, and sufficiently low charge-to-mass ratio, 1/6.3 for the heaviest masses, for further acceleration in ATLAS. In this paper, we discuss the parameters of the EBIS and the charge breeding results in a pulsed injection mode with repetition rates up to 10 Hz

Structure and stability of charged colloid-nanoparticle mixtures

Science.gov (United States)

Weight, Braden M.; Denton, Alan R.

2018-03-01

Physical properties of colloidal materials can be modified by addition of nanoparticles. Within a model of like-charged mixtures of particles governed by effective electrostatic interactions, we explore the influence of charged nanoparticles on the structure and thermodynamic phase stability of charge-stabilized colloidal suspensions. Focusing on salt-free mixtures of particles of high size and charge asymmetry, interacting via repulsive Yukawa effective pair potentials, we perform molecular dynamics simulations and compute radial distribution functions and static structure factors. Analysis of these structural properties indicates that increasing the charge and concentration of nanoparticles progressively weakens correlations between charged colloids. We show that addition of charged nanoparticles to a suspension of like-charged colloids can induce a colloidal crystal to melt and can facilitate aggregation of a fluid suspension due to attractive van der Waals interactions. We attribute the destabilizing influence of charged nanoparticles to enhanced screening of electrostatic interactions, which weakens repulsion between charged colloids. This interpretation is consistent with recent predictions of an effective interaction theory of charged colloid-nanoparticle mixtures.

Boundaries, injective envelopes, and reduced crossed products

DEFF Research Database (Denmark)

Bryder, Rasmus Sylvester

In this dissertation, we study boundary actions, equivariant injective envelopes, as well as theideal structure of reduced crossed products. These topics have recently been linked to thestudy of C-simple groups, that is, groups with simple reduced group C-algebras.In joint work with Matthew Kennedy......, we consider reduced twisted crossed products overC-simple groups. For any twisted C-dynamical system over a C-simple group, we provethat there is a one-to-one correspondence between maximal invariant ideals in the underlyingC-algebra and maximal ideals in the reduced crossed product. When......*-algebras, and relate the intersection property for group actions on unital C*-algebras to the intersection property for theequivariant injective envelope. Moreover, we also prove that the equivariant injective envelopeof the centre of the injective envelope of a unital C*-algebra can be regarded as a C...

Charge transport properties of CdMnTe radiation detectors

Directory of Open Access Journals (Sweden)

Prokopovich D. A.

2012-10-01

Full Text Available Growth, fabrication and characterization of indium-doped cadmium manganese telluride (CdMnTe radiation detectors have been described. Alpha-particle spectroscopy measurements and time resolved current transient measurements have yielded an average charge collection efficiency approaching 100 %. Spatially resolved charge collection efficiency maps have been produced for a range of detector bias voltages. Inhomogeneities in the charge transport of the CdMnTe crystals have been associated with chains of tellurium inclusions within the detector bulk. Further, it has been shown that the role of tellurium inclusions in degrading charge collection is reduced with increasing values of bias voltage. The electron drift velocity was calculated from the rise time distribution of the preamplifier output pulses at each measured bias. From the dependence of drift velocity on applied electric field the electron mobility was found to be μn = (718 ± 55 cm2/Vs at room temperature.

Design of the low energy beam transport line between CARIBU and the EBIS charge breeder

Energy Technology Data Exchange (ETDEWEB)

Perry, A., E-mail: aperry4@hawk.iit.edu [Argonne National Laboratory, Argonne, IL 60439, USA and Illinois Institute of Technology, Chicago, IL 60616 (United States); Ostroumov, P. N.; Barcikowski, A.; Dickerson, C.; Kondrashev, S. A.; Mustapha, B.; Savard, G. [Argonne National Laboratory, Argonne, IL 60439 (United States)

2015-01-09

An Electron Beam Ion Source Charge Breeder (EBIS-CB) has been developed to breed radioactive beams from the CAlifornium Rare Isotope Breeder Upgrade (CARIBU) facility at ATLAS. The EBIS-CB will replace the existing ECR charge breeder to increase the intensity and improve the purity of reaccelerated radioactive ion beams. The EBIS-CB is in the final stage of off-line commissioning. Currently, we are developing a low energy beam transport (LEBT) system to transfer CARIBU beams to the EBIS-CB. As was originally planned, an RFQ cooler-buncher will precede the EBIS-CB. Recently, it was decided to include a multi-reflection time-of-flight (MR-TOF) mass-spectrometer following the RFQ. MR-TOF is a relatively new technology used to purify beams with a mass-resolving power up to 3×10{sup 5} as was demonstrated in experiments at CERN/ISOLDE. Very high purity singly-charged radioactive ion beams will be injected into the EBIS for charge breeding and due to its inherent properties, the EBIS-CB will maintain the purity of the charge bred beams. Possible contamination of residual gas ions will be greatly suppressed by achieving ultra-high vacuum in the EBIS trap. This paper will present and discuss the design of the LEBT and the overall integration of the EBIS-CB into ATLAS.

Effects of turbulence enhancement on combustion process using a double injection strategy in direct-injection spark-ignition (DISI) gasoline engines

International Nuclear Information System (INIS)

Kim, Taehoon; Song, Jingeun; Park, Sungwook

2015-01-01

Highlights: • Using double injection strategy, turbulent kinetic energy can be improved with slight decrease in mixture homogeneity. • Retarded first injection timing reduces vapor fuel loss to intake port. • Double injection increases tumble intensity. • High turbulent intensity caused by double injection increases flame propagation speed. - Abstract: Direct-injection spark-ignition (DISI) gasoline engines have been spotlighted due to their high thermal efficiency. Increase in the compression ratio that result from the heat absorption effect of fuel vaporization induces higher thermal efficiency than found in port fuel injection (PFI) engines. Since fuel is injected at the cylinder directly, various fuel injection strategies can be used. In this study, turbulent intensity was improved by a double injection strategy while maintaining mixture homogeneity. To analyze the turbulence enhancement effects using the double injection strategy, a side fuel injected, homogeneous-charge-type DISI gasoline engine with a multi-hole-type injector was utilized. The spray model was evaluated using experimental data for various injection pressures and the combustion model was evaluated for varied ignition timing. First and second injection timing was swept by 20 degree interval. The turbulent kinetic energy and mixture inhomogeneity index were mapped. First injection at the middle of the intake stroke and second injection early in the compression stroke showed improved turbulent characteristics that did not significantly decrease with mixture homogeneity. A double injection case that showed improved turbulent intensity while maintaining an adequate level of mixture homogeneity and another double injection case that showed significantly improved turbulent intensity with a remarkable decrease in mixture homogeneity were considered for combustion simulation. We found that the improved turbulent intensity increased the flame propagation speed. Also, the mixture homogeneity

Negative plates for dry-charged lead storage batteries. [higher charging capacity when impregnated with tannin solution

Energy Technology Data Exchange (ETDEWEB)

Fiedler, V; Malikova, V; Weber, H

1970-09-15

Impregnation of negative plates with acid solutions of sulfomethylated tannins was found to improve the charging properties at low temperatures. Methods for synthesizing tannins are described. Charging capacity at 0/sup 0/ was 7.3A. (RWR)

Micro-powder injection moulding of tungsten

International Nuclear Information System (INIS)

Zeep, B.

2007-12-01

For He-cooled Divertors as integral components of future fusion power plants, about 300000 complex shaped tungsten components are to be fabricated. Tungsten is the favoured material because of its excellent properties (high melting point, high hardness, high sputtering resistance, high thermal conductivity). However, the material's properties cause major problems for large scale production of complex shaped components. Due to the resistance of tungsten to mechanical machining, new fabrication technologies have to be developed. Powder injection moulding as a well established shaping technology for a large scale production of complex or even micro structured parts might be a suitable method to produce tungsten components for fusion applications but is not yet commercially available. The present thesis is dealing with the development of a powder injection moulding process for micro structured tungsten components. To develop a suitable feedstock, the powder particle properties, the binder formulation and the solid load were optimised. To meet the requirements for a replication of micro patterned cavities, a special target was to define the smallest powder particle size applicable for micro-powder injection moulding. To investigate the injection moulding performance of the developed feedstocks, experiments were successfully carried out applying diverse cavities with structural details in micro dimension. For debinding of the green bodies, a combination of solvent debinding and thermal debinding has been adopted for injection moulded tungsten components. To develop a suitable debinding strategy, a variation of the solvent debinding time, the heating rate and the binder formulation was performed. For investigating the thermal consolidation behaviour of tungsten components, sinter experiments were carried out applying tungsten powders suitable for micro-powder injection moulding. First mechanical tests of the sintered samples showed promising material properties such as a

Analysis of Turbulent Combustion in Simplified Stratified Charge Conditions

Science.gov (United States)

Moriyoshi, Yasuo; Morikawa, Hideaki; Komatsu, Eiji

The stratified charge combustion system has been widely studied due to the significant potentials for low fuel consumption rate and low exhaust gas emissions. The fuel-air mixture formation process in a direct-injection stratified charge engine is influenced by various parameters, such as atomization, evaporation, and in-cylinder gas motion at high temperature and high pressure conditions. It is difficult to observe the in-cylinder phenomena in such conditions and also challenging to analyze the following stratified charge combustion. Therefore, the combustion phenomena in simplified stratified charge conditions aiming to analyze the fundamental stratified charge combustion are examined. That is, an experimental apparatus which can control the mixture distribution and the gas motion at ignition timing was developed, and the effects of turbulence intensity, mixture concentration distribution, and mixture composition on stratified charge combustion were examined. As a result, the effects of fuel, charge stratification, and turbulence on combustion characteristics were clarified.

Syringe injectable electronics

Science.gov (United States)

Hong, Guosong; Zhou, Tao; Jin, Lihua; Duvvuri, Madhavi; Jiang, Zhe; Kruskal, Peter; Xie, Chong; Suo, Zhigang; Fang, Ying; Lieber, Charles M.

2015-01-01

Seamless and minimally-invasive three-dimensional (3D) interpenetration of electronics within artificial or natural structures could allow for continuous monitoring and manipulation of their properties. Flexible electronics provide a means for conforming electronics to non-planar surfaces, yet targeted delivery of flexible electronics to internal regions remains difficult. Here, we overcome this challenge by demonstrating syringe injection and subsequent unfolding of submicrometer-thick, centimeter-scale macroporous mesh electronics through needles with a diameter as small as 100 micrometers. Our results show that electronic components can be injected into man-made and biological cavities, as well as dense gels and tissue, with > 90% device yield. We demonstrate several applications of syringe injectable electronics as a general approach for interpenetrating flexible electronics with 3D structures, including (i) monitoring of internal mechanical strains in polymer cavities, (ii) tight integration and low chronic immunoreactivity with several distinct regions of the brain, and (iii) in vivo multiplexed neural recording. Moreover, syringe injection enables delivery of flexible electronics through a rigid shell, delivery of large volume flexible electronics that can fill internal cavities and co-injection of electronics with other materials into host structures, opening up unique applications for flexible electronics. PMID:26053995

Chemical Looping Combustion with Different Types of Liquid Fuels Combustion en boucle chimique avec différentes charges liquides

Directory of Open Access Journals (Sweden)

Hoteit A.

2011-02-01

Full Text Available CLC is a new promising combustion process for CO2 capture with less or even no energy penalty compared to other processes. Up to now, most of the work performed on CLC was conducted with gaseous or solid fuels, using methane and coal and/or pet coke. Liquid fuels such as heavy fuels resulting from oil distillation or conversion may also be interesting feedstocks to consider. However, liquid fuels are challenging feedstock to deal with in fluidized beds. The objective of the present work is therefore to investigate the feasibility of liquid feed injection and contact with oxygen carrier in CLC conditions in order to conduct partial or complete combustion of hydrocarbons. A batch experimental fluidized bed set-up was developed to contact alternatively oxygen carrier with liquid fuels or air. The 20 mm i.d. fluidized bed reactor was filled up with 45 g of NiAl0.44O1.67 and pulses of 1-2 g of liquid were injected in the bed at high temperatures up to 950˚C. Different feedstocks have been injected, from dodecane to heavy fuel oils No.2. Results show that, during the reduction period, it is possible to convert all the fuel injected and there is no coke remaining on particles at the end of the reduction step. Depending upon oxygen available in the bed, either full combustion or partial combustion can be achieved. Similar results were found with different liquid feeds, despite their different composition and properties. Le CLC est un nouveau concept prometteur appliqué à la combustion qui permet le captage de CO en minimisant la pénalité énergétique liée au captage. Jusqu’à présent, l’essentiel des travaux de recherche dans le domaine du CLC concerne les charges gazeuses (méthane et solides (charbon et coke. Les charges liquides, et particulièrement les résidus pétroliers, sont des charges également intéressantes à considérer a priori. La mise en oeuvre de ces charges en lit fluidisé est cependant délicate. L’objet de ce

Mechanical Properties of Surface-Charged Poly(Methyl Methacrylate as Denture Resins

Directory of Open Access Journals (Sweden)

Sang E. Park

2009-01-01

Full Text Available The aim of this study was to examine the mechanical properties of a new surface-modified denture resin for its suitability as denture base material. This experimental resin is made by copolymerization of methacrylic acid (MA to poly(methyl methacrylate (PMMA to produce a negative charge. Four experimental groups consisted of Orthodontic Dental Resin (DENTSPLY Caulk as a control and three groups of modified PMMA (mPMMA produced at differing ratios of methacrylic acid (5 : 95, 10 : 90, and 20 : 80 MA : MMA. A 3-point flexural test using the Instron Universal Testing Machine (Instron Corp. measured force-deflection curves and a complete stress versus strain history to calculate the transverse strength, transverse deflection, flexural strength, and modulus of elasticity. Analysis of Variance and Scheffe Post-test were performed on the data. Resins with increased methacrylic acid content exhibited lower strength values for the measured physical properties. The most significant decrease occurred as the methacrylic acid content was increased to 20% mPMMA. No significant differences at P<.05 were found in all parameters tested between the Control and 5% mPMMA.

Single Photon, Spin, and Charge in Diamond Semiconductor at room temperature

International Nuclear Information System (INIS)

Yuki Doi

2014-01-01

The nitrogen-vacancy (NV) center in diamond is a promising candidate for a qubit driven at room temperature. In order to derive potential of NV center, manipulation of their charge state is a very important topic. Here we succeeded to electrically control between single NV-/NV0 by means of current injection. This method allows us to very stable charge state control. (author)

Protein denaturation and functional properties of Lenient Steam Injection heat treated whey protein concentrate

DEFF Research Database (Denmark)

Dickow, Jonatan Ahrens; Kaufmann, Niels; Wiking, Lars

2012-01-01

Whey protein concentrate (WPC) was heat treated by use of the novel heat treatment method of Lenient Steam Injection (LSI) to elucidate new functional properties in relation to heat-induced gelation of heat treated WPC. Denaturation was measured by both DSC and FPLC, and the results of the two...... methods were highly correlated. Temperatures of up to 90 °C were applicable using LSI, whereas only 68 °C could be reached by plate heat exchange before coagulation/fouling. Denaturation of whey proteins increased with increasing heat treatment temperature up to a degree of 30–35% denaturation at 90 °C...

A Power-Efficient Wireless Capacitor Charging System Through an Inductive Link.

Science.gov (United States)

Lee, Hyung-Min; Ghovanloo, Maysam

2013-10-01

A power-efficient wireless capacitor charging system for inductively powered applications has been presented. A bank of capacitors can be directly charged from an ac source by generating a current through a series charge injection capacitor and a capacitor charger circuit. The fixed charging current reduces energy loss in switches, while maximizing the charging efficiency. An adaptive capacitor tuner compensates for the resonant capacitance variations during charging to keep the amplitude of the ac input voltage at its peak. We have fabricated the capacitor charging system prototype in a 0.35- μ m 4-metal 2-poly standard CMOS process in 2.1 mm 2 of chip area. It can charge four pairs of capacitors sequentially. While receiving 2.7-V peak ac input through a 2-MHz inductive link, the capacitor charging system can charge each pair of 1 μ F capacitors up to ±2 V in 420 μ s, achieving a high measured charging efficiency of 82%.

Plasma injection from the independent SHF-source in the open configuration 2. Magnetic fields of magnetic mirror configurations

International Nuclear Information System (INIS)

Beriya, Z.R.; Gogashvili, G.E.; Nanobashvili, S.I.

1992-01-01

The investigation was aimed at studying the characteristics and properties of plasma injected from independent stationary SHF source into an open magnetic trap of mirror geometry within a wide range of change in the experimental conditions. The investigations were primarily based on measurements of the distribution of charged particles in a plasma along the trap and on the dependence of the concentration on plasma production conditions in a SHF source. It is shown that the aggregate of the experimental data enables a conclusion that independent of SHF plasma can be succesfully used for filling on open magnetic trap of mirror configuration with plasma

Discrete allowed and forbidden states in the classical mechanical domain in the charged particle motion in a magnetic field

International Nuclear Information System (INIS)

Varma, R.K.; Punithavelu, A.M.; Banerjee, S.B.

1994-01-01

The properties of the motion of charged particles injected almost parallel to the magnetic field are studied by measuring the electron current as a function of the cathode voltage (electron energy), as electrons from the gun traverse a distance L to the detector. The plate current is found to exhibit oscillatory behaviour in contradistinction with the behaviour expected according to the standard classical mechanical paradigm, with the peaks fitting a relation obtained from a quantum like theory predicting such a behaviour. (author). 4 refs, 1 fig, 1 tab

Physical Property Changes During CO2 Injection into Sandstone from Pukpyeong Formation, South Korea: Pore-scale Approach

Science.gov (United States)

Han, J.; Keehm, Y.

2010-12-01

Carbon dioxide is believed to be responsible for global warming and climate change, and Korea government puts a great effort in CCS (Carbon Capture and Storage). The geological sequestration is regarded as one viable option and we are looking for prospecting formations for carbon storage. In this paper, we present a new approach to determine physical property changes during CO2 injection and preliminary results from applying the method to one of prospective Tertiary formation in South Korea. The so-called computational rock physics method is composed of three steps: 1) acquisition of high-resolution pore microstructures by X-ray micro-tomography; 2) CO2 injection simulation using lattice-Boltzmann (LB) two-phase flow simulation; and 3) FEM property simulations (electrical and elastic) at different CO2 saturations during the injection. We have been shown the viability of the method last year. This year we applied this method to one of CS (carbon storage) target area, Pukpyeong formation located in north-eastern part of South Korea. From thin section analysis, we found that the formation is composed of mudstone, sandstone and conglomerate, and most of them are poorly consolidated. The mudstone and poorly-sorted conglomerate are believed to have very low permeability, and the effect of CO2 injection would be significant. Thus we focus on sandstone units and get pore microstructure of those units. We then performed the computational rock physics analysis, and present the relations of Vp - CO2 saturation, and electrical conductivity - CO2 saturation for a few sand units. We also present the preliminary upscaling results by putting combined sandstone and mudstone units into FEM modeling. The modeling results implies that the new computational approach can be very useful to characterizing the CS sites especially in early stage. Acknowledgement: This work was supported by the Energy R&D program of the Korea Institute of Energy Technology Evaluation and Planning (KETEP

Charge exchange cooling in the tandem mirror plasma confinement apparatus

International Nuclear Information System (INIS)

Logan, B.G.

1978-01-01

A method and apparatus are described for cooling a plasma confined in the center mirror cell of the tandem mirror apparatus by injecting cold neutral species of the plasma into at least one mirroring region of the center mirror cell. The cooling is due to the loss of warm charged species through charge exchange with the cold neutral species with resulting diffusion of the warm neutral species out of the plasma

Injection of electrons by colliding laser pulses in a laser wakefield accelerator

Energy Technology Data Exchange (ETDEWEB)

Hansson, M., E-mail: martin.hansson@fysik.lth.se; Aurand, B.; Ekerfelt, H.; Persson, A.; Lundh, O.

2016-09-01

To improve the stability and reproducibility of laser wakefield accelerators and to allow for future applications, controlling the injection of electrons is of great importance. This allows us to control the amount of charge in the beams of accelerated electrons and final energy of the electrons. Results are presented from a recent experiment on controlled injection using the scheme of colliding pulses and performed using the Lund multi-terawatt laser. Each laser pulse is split into two parts close to the interaction point. The main pulse is focused on a 2 mm diameter gas jet to drive a nonlinear plasma wave below threshold for self-trapping. The second pulse, containing only a fraction of the total laser energy, is focused to collide with the main pulse in the gas jet under an angle of 150°. Beams of accelerated electrons with low divergence and small energy spread are produced using this set-up. Control over the amount of accelerated charge is achieved by rotating the plane of polarization of the second pulse in relation to the main pulse. Furthermore, the peak energy of the electrons in the beams is controlled by moving the collision point along the optical axis of the main pulse, and thereby changing the acceleration length in the plasma. - Highlights: • Compact colliding pulse injection set-up used to produce low energy spread e-beams. • Beam charge controlled by rotating the polarization of injection pulse. • Peak energy controlled by point of collision to vary the acceleration length.

Extremally charged line

International Nuclear Information System (INIS)

Ryzner, Jirí; Žofka, Martin

2016-01-01

We investigate the properties of a static, cylindrically symmetric Majumdar–Papapetrou-type solution of Einstein–Maxwell equations. We locate its singularities, establish its algebraic type, find its asymptotic properties and weak-field limit, study the structure of electrogeodesics, and determine the mass and charge of its sources. We provide an interpretation of the spacetime and discuss the parameter appearing in the metric. (paper)

One-carrier free space charge motion under applied voltage

International Nuclear Information System (INIS)

Camargo, P.C.; Ferreira, G.F.L.

1976-01-01

The system of partial differential equations describing the one-carrier free space-charge motion under a given applied voltage is transformed into a system of two ordinary differential equations. The method is applied to find the external current injection [pt

Optical properties of two-dimensional charge density wave materials

Science.gov (United States)

Sayers, Charles; Karbassi, Sara; Friedemann, Sven; da Como, Enrico

Titanium diselenide (TiSe2) is a member of the layered transition metal dichalcogenide (TMD) materials. It exhibits unusual chiral charge ordering below 190 K after undergoing an initial phase transition to a commensurate (2 x 2 x 2) charge density wave (CDW) at 200 K which is enhanced further in the monolayer. Recently, the first evidence of chirality in a CDW system was discovered in this material by scanning tunneling microscopy and time-resolved reflectivity experiments, where separate left and right handed charge-ordered domains were found to exist within a single sample. We have prepared single crystals of 1T-TiSe2 using iodine vapour transport, and confirmed their quality by x-ray analysis and charge transport measurements. Using a combination of polarised optical spectroscopy techniques in the mid to far infrared (4 to 700 meV photon energy), we have measured an anisotropy relating to the CDW gap. We discuss the results on the basis of chiral domains with different handedness and the nature of the CDW transition.

Direct injection of high pressure gas : scaling properties of pulsed turbulent jets

NARCIS (Netherlands)

Baert, R.S.G.; Klaassen, A.; Doosje, E.

2010-01-01

Existing gasoline DI injection equipment has been modified to generate single hole pulsed gas jets. Injection experiments have been performed at combinations of 3 different pressure ratios (2 of which supercritical) respectively 3 different hole geometries (i.e. length to diameter ratios). Injection

Charge collection properties of heavily irradiated epitaxial silicon detectors

International Nuclear Information System (INIS)

Kramberger, G.; Cindro, V.; Dolenc, I.; Fretwurst, E.; Lindstroem, G.; Mandic, I.; Mikuz, M.; Zavrtanik, M.

2005-01-01

Detectors processed on epitaxial silicon seem to be a viable solution for the extreme radiation levels in the innermost layers of tracking detectors at upgraded LHC (SLHC). A set of epitaxial pad detectors of 50 and 75μm thicknesses (ρ=50Ωcm) was irradiated with 24GeV/c protons and reactor neutrons up to equivalent fluences of 10 16 cm -2 . Charge collection for minimum ionizing electrons from a 90 Sr source was measured using a charge sensitive preamplifier and a 25ns shaping circuit. The dependence of collected charge on annealing time and operation temperature was studied. Results were used to predict the performance of fine pitch pixel detectors proposed for SLHC

Charge collection properties of heavily irradiated epitaxial silicon detectors

Energy Technology Data Exchange (ETDEWEB)

Kramberger, G. [Institute Jozef Stefan, Jamova 39, SI-1111 Ljubljana (Slovenia)]. E-mail: Gregor.Kramberger@ijs.si; Cindro, V. [Institute Jozef Stefan, Jamova 39, SI-1111 Ljubljana (Slovenia); Dolenc, I. [Institute Jozef Stefan, Jamova 39, SI-1111 Ljubljana (Slovenia); Fretwurst, E. [University of Hamburg, Institut fuer Experimentalphysik, Luruper Chaussee 149, D-22761 Hamburg (Germany); Lindstroem, G. [University of Hamburg, Institut fuer Experimentalphysik, Luruper Chaussee 149, D-22761 Hamburg (Germany); Mandic, I. [Institute Jozef Stefan, Jamova 39, SI-1111 Ljubljana (Slovenia); Mikuz, M. [Institute Jozef Stefan, Jamova 39, SI-1111 Ljubljana (Slovenia); Zavrtanik, M. [Institute Jozef Stefan, Jamova 39, SI-1111 Ljubljana (Slovenia)

2005-12-01

Detectors processed on epitaxial silicon seem to be a viable solution for the extreme radiation levels in the innermost layers of tracking detectors at upgraded LHC (SLHC). A set of epitaxial pad detectors of 50 and 75{mu}m thicknesses ({rho}=50{omega}cm) was irradiated with 24GeV/c protons and reactor neutrons up to equivalent fluences of 10{sup 16}cm{sup -2}. Charge collection for minimum ionizing electrons from a {sup 90}Sr source was measured using a charge sensitive preamplifier and a 25ns shaping circuit. The dependence of collected charge on annealing time and operation temperature was studied. Results were used to predict the performance of fine pitch pixel detectors proposed for SLHC.

Computer-aided injection molding system

Science.gov (United States)

Wang, K. K.; Shen, S. F.; Cohen, C.; Hieber, C. A.; Isayev, A. I.

1982-10-01

Achievements are reported in cavity-filling simulation, modeling viscoelastic effects, measuring and predicting frozen-in birefringence in molded parts, measuring residual stresses and associated mechanical properties of molded parts, and developing an interactive mold-assembly design program and an automatic NC maching data generation and verification program. The Cornell Injection Molding Program (CIMP) consortium is discussed as are computer user manuals that have been published by the consortium. Major tasks which should be addressed in future efforts are listed, including: (1) predict and experimentally determine the post-fillin behavior of thermoplastics; (2) simulate and experimentally investigate the injection molding of thermosets and filled materials; and (3) further investigate residual stresses, orientation and mechanical properties.

Particle injection into the Castor tokamak by electric arcs

International Nuclear Information System (INIS)

Hildebrandt, D.; Juettner, B.; Pursch, H.; Jakubka, K.; Stoeckel, J.; Zacek, F.

1989-01-01

The influence of arcing on the tokamak discharge was investigated in the Castor tokamak. A special calibrated gun which emitted tantalum by artificially ignited electric arcs, was used to study the transport of the injected tantalum ions, neutrals and droplets. The injection of tantalum led to an increase in electron density and to a change of plasma position only if the transported charge was higher than 0.01 C. As the naturally occurring arcs are well below this limit, the arcing in tokamaks is rather the consequence than the reason of instabilities. (J.U.)

TRANSVERSE PHASE SPACE PAINTING FOR SNS ACCUMULATOR RING INJECTION.

Energy Technology Data Exchange (ETDEWEB)

BEEBE-WANG,J.; LEE,Y.Y.; RAPARIA,D.; WEI,J.

1999-03-29

The result of investigation and comparison of a series of transverse phase space painting schemes for the injection of SNS accumulator ring [1] is reported. In this computer simulation study, the focus is on the creation of closed orbit bumps that give desired distributions at the target. Space charge effects such as tune shift, emittance growth and beam losses are considered. The results of pseudo end-to-end simulations from the injection to the target through the accumulator ring and Ring to Target Beam Transfer (RTBT) system [2] are presented and discussed.

End Uses Mechanical Properties Settled By The Modified Sintering Conditions Of The Metal Injection Molding Process

International Nuclear Information System (INIS)

Marray, Tarek; Jaccquet, Philippe; Moinard-Checot, Delphine; Fabre, Agnes; Barrallier, Laurent

2011-01-01

Most common mechanical applications require parts with specific properties as hard faced features. It is well known that treating parts under suitable atmospheres may improve hardness and strength yield of steels. Heat treatment process and more particularly thermo-chemical diffusion processes (such as carburizing or its variation: carbonitriding) can be performed to reach the industrial hardness profile requirements. In this work, a low-alloyed steel feedstock based on water soluble binder system is submitted to the MIM process steps (including injection molding, debinding and sintering). As-sintered parts are then treated under a low pressure carbonitriding treatment. This contribution focuses on preliminary results such as microstructural analyses and mechanical properties which are established at each stage of the process to determine and monitor changes.

Magnetic confinement system using charged ammonia targets

International Nuclear Information System (INIS)

Porter, G.D.; Bogdanoff, A.

1979-01-01

A system is described for guiding charged laser targets to a predetermined focal spot of a laser along generally arbitrary, and especially horizontal, directions which comprises a series of electrostatic sensors which provide inputs to a computer for real time calculation of position, velocity, and direction of the target along an initial injection trajectory

Exhaust emissions from an indirect injection dual-fuel engine

International Nuclear Information System (INIS)

Abd Alla, G.H.; Badr, O.A.; Soliman, H.A.; Abd Rabbo, M.F.

2000-01-01

Diesel engines operating on gaseous fuels are commonly known as dual-fuel engines. In the present work, a single-cylinder, compression ignition, indirect injection research (Ricardo E6) engine has been installed at United Arab Emirates University for investigation of the exhaust emissions when the engine is operating as a dual-fuel engine. The influence of changes in major operating and design parameters, such as the concentration of gaseous fuel in the cylinder charge, pilot fuel quantity, injection timing and intake temperature, on the production of exhaust emissions was investigated. Diesel fuel was used as the pilot fuel, while methane or propane was used as the main fuel which was inducted in the intake manifold and mixed with the intake air. The experimental investigations showed that the poor emissions at light loads can be improved significantly by increasing the concentration of gaseous fuel (total equivalence ratio), employing a large pilot fuel quantity, advancing the injection timing of the pilot fuel and increasing the intake temperature. It is demonstrated that, in general, any measure that tends to increase the size of the combustion regions within the overly lean cylinder charge will reduce markedly the concentrations of unburned hydrocarbons and carbon monoxide in the exhaust gases. (Author)

Exhaust emissions from an indirect injection dual-fuel engine

Energy Technology Data Exchange (ETDEWEB)

Abd Alla, G.H.; Badr, O.A.; Soliman, H.A.; Abd Rabbo, M.F. [Zagazig Univ., Dept. of Mechanical Engineering, Cairo (Egypt)

2000-04-01

Diesel engines operating on gaseous fuels are commonly known as dual-fuel engines. In the present work, a single-cylinder, compression ignition, indirect injection research (Ricardo E6) engine has been installed at United Arab Emirates University for investigation of the exhaust emissions when the engine is operating as a dual-fuel engine. The influence of changes in major operating and design parameters, such as the concentration of gaseous fuel in the cylinder charge, pilot fuel quantity, injection timing and intake temperature, on the production of exhaust emissions was investigated. Diesel fuel was used as the pilot fuel, while methane or propane was used as the main fuel which was inducted in the intake manifold and mixed with the intake air. The experimental investigations showed that the poor emissions at light loads can be improved significantly by increasing the concentration of gaseous fuel (total equivalence ratio), employing a large pilot fuel quantity, advancing the injection timing of the pilot fuel and increasing the intake temperature. It is demonstrated that, in general, any measure that tends to increase the size of the combustion regions within the overly lean cylinder charge will reduce markedly the concentrations of unburned hydrocarbons and carbon monoxide in the exhaust gases. (Author)

Feedback correction of injection errors using digital signal-processing techniques

Directory of Open Access Journals (Sweden)

N. S. Sereno

2007-01-01

Full Text Available Efficient transfer of electron beams from one accelerator to another is important for 3rd-generation light sources that operate using top-up. In top-up mode, a constant amount of charge is injected at regular intervals into the storage ring to replenish beam lost primarily due to Touschek scattering. Top-up therefore requires that the complex of injector accelerators that fill the storage ring transport beam with a minimum amount of loss. Injection can be a source of significant beam loss if not carefully controlled. In this note we describe a method of processing injection transient signals produced by beam-position monitors and using the processed data in feedback. Feedback control using the technique described here has been incorporated in the Advanced Photon Source (APS booster synchrotron to correct injection transients.

Charge and spin transport in mesoscopic superconductors

Directory of Open Access Journals (Sweden)

M. J. Wolf

2014-02-01

Full Text Available Background: Non-equilibrium charge transport in superconductors has been investigated intensely in the 1970s and 1980s, mostly in the vicinity of the critical temperature. Much less attention has been paid to low temperatures and the role of the quasiparticle spin.Results: We report here on nonlocal transport in superconductor hybrid structures at very low temperatures. By comparing the nonlocal conductance obtained by using ferromagnetic and normal-metal detectors, we discriminate charge and spin degrees of freedom. We observe spin injection and long-range transport of pure, chargeless spin currents in the regime of large Zeeman splitting. We elucidate charge and spin transport by comparison to theoretical models.Conclusion: The observed long-range chargeless spin transport opens a new path to manipulate and utilize the quasiparticle spin in superconductor nanostructures.

Radial plasma profile and neutron yield in an adiabatic trap with fast atom injection

International Nuclear Information System (INIS)

Panov, D.A.

1988-01-01

Radial profiles of ion densities depending on two dimensionless parameters, which values are determined by the trap, plasma and injected beam parameters are found in dimensionless units for a plasma generated by fast atom injection in an adiabatic trap. The calculated profiles are used for determining the neutron yield. Simple approximated dimensional relations permitting to estimate quickly neutron yield, required injection power, flux of charge exchange atoms on the wall around the plasma in a wide energy range of injected atoms, trap field modulud, injection angle, trap radius and length are determined. The energetic efficiency of neutron production is estimated and it is shown that it grows with the injection energy. 7 refs.; 7 figs

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

Energy Technology Data Exchange (ETDEWEB)

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

2012-06-15

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

Data-driven fault mechanics: Inferring fault hydro-mechanical properties from in situ observations of injection-induced aseismic slip

Science.gov (United States)

Bhattacharya, P.; Viesca, R. C.

2017-12-01

In the absence of in situ field-scale observations of quantities such as fault slip, shear stress and pore pressure, observational constraints on models of fault slip have mostly been limited to laboratory and/or remote observations. Recent controlled fluid-injection experiments on well-instrumented faults fill this gap by simultaneously monitoring fault slip and pore pressure evolution in situ [Gugleilmi et al., 2015]. Such experiments can reveal interesting fault behavior, e.g., Gugleilmi et al. report fluid-activated aseismic slip followed only subsequently by the onset of micro-seismicity. We show that the Gugleilmi et al. dataset can be used to constrain the hydro-mechanical model parameters of a fluid-activated expanding shear rupture within a Bayesian framework. We assume that (1) pore-pressure diffuses radially outward (from the injection well) within a permeable pathway along the fault bounded by a narrow damage zone about the principal slip surface; (2) pore-pressure increase ativates slip on a pre-stressed planar fault due to reduction in frictional strength (expressed as a constant friction coefficient times the effective normal stress). Owing to efficient, parallel, numerical solutions to the axisymmetric fluid-diffusion and crack problems (under the imposed history of injection), we are able to jointly fit the observed history of pore-pressure and slip using an adaptive Monte Carlo technique. Our hydrological model provides an excellent fit to the pore-pressure data without requiring any statistically significant permeability enhancement due to the onset of slip. Further, for realistic elastic properties of the fault, the crack model fits both the onset of slip and its early time evolution reasonably well. However, our model requires unrealistic fault properties to fit the marked acceleration of slip observed later in the experiment (coinciding with the triggering of microseismicity). Therefore, besides producing meaningful and internally consistent

Charge dividing mechanism on resistive electrode in position-sensitive detectors

International Nuclear Information System (INIS)

Radeka, V.; Rehak, P.

1978-10-01

A complete charge-division mechanism, including both the diffusion and the electromagnetic wave propagation on resistive electrodes, is presented. The charge injected into such a transmission line divides between the two ends according to the ratio of resistancies and independently of the value of the line resistance, of the propagation mechanism and of the distribution of inductance and capacitance along the line. The shortest charge division time is achieved for Rl = 2π (L/C) 1 / 2 , where R, L, C are resistance, inductance and capacitance per unit length and l is the length of the line

Syringe-injectable electronics.

Science.gov (United States)

Liu, Jia; Fu, Tian-Ming; Cheng, Zengguang; Hong, Guosong; Zhou, Tao; Jin, Lihua; Duvvuri, Madhavi; Jiang, Zhe; Kruskal, Peter; Xie, Chong; Suo, Zhigang; Fang, Ying; Lieber, Charles M

2015-07-01

Seamless and minimally invasive three-dimensional interpenetration of electronics within artificial or natural structures could allow for continuous monitoring and manipulation of their properties. Flexible electronics provide a means for conforming electronics to non-planar surfaces, yet targeted delivery of flexible electronics to internal regions remains difficult. Here, we overcome this challenge by demonstrating the syringe injection (and subsequent unfolding) of sub-micrometre-thick, centimetre-scale macroporous mesh electronics through needles with a diameter as small as 100 μm. Our results show that electronic components can be injected into man-made and biological cavities, as well as dense gels and tissue, with >90% device yield. We demonstrate several applications of syringe-injectable electronics as a general approach for interpenetrating flexible electronics with three-dimensional structures, including (1) monitoring internal mechanical strains in polymer cavities, (2) tight integration and low chronic immunoreactivity with several distinct regions of the brain, and (3) in vivo multiplexed neural recording. Moreover, syringe injection enables the delivery of flexible electronics through a rigid shell, the delivery of large-volume flexible electronics that can fill internal cavities, and co-injection of electronics with other materials into host structures, opening up unique applications for flexible electronics.

Preliminary study on functional performance of compound type multistage safety injection tank

International Nuclear Information System (INIS)

Bae, Youngmin; Kim, Young In; Kim, Keung Koo

2015-01-01

Highlights: • Functional performance of compound type multistage safety injection tanks is studied. • Effects of key design parameters are scrutinized. • Distinctive flow features in compound type safety injection tanks are explored. - Abstract: A parametric study is carried out to evaluate the functional performance of a compound type multistage safety injection tank that would be considered one of the components for the passive safety injection systems in nuclear power plants. The effects of key design parameters such as the initial volume fraction and charging pressure of gas, tank elevation, vertical location of a sparger, resistance coefficient, and operating condition on the injection flow rate are scrutinized along with a discussion of the relevant flow features. The obtained results indicate that the compound type multistage safety injection tank can effectively control the injection flow rate in a passive manner, by switching the driving force for the safety injection from gas pressure to gravity during the refill and reflood phases, respectively

Gain measurements of the Ca-Xe charge exchange system. [for UV lasers

Science.gov (United States)

Michels, C. J.; Chubb, D. L.

1978-01-01

Charge-exchange-pumped Ca(+) was studied for possible positive laser gain at 370.6 and 315.9 nm using an Xe MPD arc as the Xe(+) source. The present paper describes the MPD arc, the calcium injection system, the diagnostics for gain, and spontaneous emission measurements and results. No positive gain measurements were observed. A small Xe-Ca charge exchange cross section compared to He-metal laser systems charge exchange cross sections is the most probable reason why the result was negative.

The Influence of Pre-Conditioning on Space Charge Formation in LDPE

DEFF Research Database (Denmark)

Fleming, Robert J.; Henriksen, Mogens; Holbøll, Joachim T.

1996-01-01

In this paper we present space charge accumulation data for planar low density polyethylene samples subjected to 20 kV/mm dc fields at room temperature. The data were obtained using the laser-induced-pressure-pulse (LIPP) technique. Some of the samples were conditioned by holding them at 40oC in ......C in short-circuit at rotary pump pressure for 48 hr prior to measurement. Such conditioning had no consistent effect on the space charge. The extent of charge injection/extraction at the semicon electrodes appeared to vary considerably between samples....

Neutral beam injection and plasma convection in a magnetic field

International Nuclear Information System (INIS)

Okuda, H.; Hiroe, S.

1988-06-01

Injection of a neutral beam into a plasma in a magnetic field has been studied by means of numerical plasma simulations. It is found that, in the absence of a rotational transform, the convection electric field arising from the polarization charges at the edges of the beam is dissipated by turbulent plasma convection, leading to anomalous plasma diffusion across the magnetic field. The convection electric field increases with the beam density and beam energy. In the presence of a rotational transform, polarization charges can be neutralized by the electron motion along the magnetic field. Even in the presence of a rotational transform, a steady-state convection electric field and, hence, anomalous plasma diffusion can develop when a neutral beam is constantly injected into a plasma. Theoretical investigations on the convection electric field are described for a plasma in the presence of rotational transform. 11 refs., 19 figs

Minimization of power consumption during charging of superconducting accelerating cavities

Energy Technology Data Exchange (ETDEWEB)

Bhattacharyya, Anirban Krishna, E-mail: anirban.bhattacharyya@physics.uu.se; Ziemann, Volker; Ruber, Roger; Goryashko, Vitaliy

2015-11-21

The radio frequency cavities, used to accelerate charged particle beams, need to be charged to their nominal voltage after which the beam can be injected into them. The standard procedure for such cavity filling is to use a step charging profile. However, during initial stages of such a filling process a substantial amount of the total energy is wasted in reflection for superconducting cavities because of their extremely narrow bandwidth. The paper presents a novel strategy to charge cavities, which reduces total energy reflection. We use variational calculus to obtain analytical expression for the optimal charging profile. Energies, reflected and required, and generator peak power are also compared between the charging schemes and practical aspects (saturation, efficiency and gain characteristics) of power sources (tetrodes, IOTs and solid state power amplifiers) are also considered and analysed. The paper presents a methodology to successfully identify the optimal charging scheme for different power sources to minimize total energy requirement.

Minimization of power consumption during charging of superconducting accelerating cavities

International Nuclear Information System (INIS)

Bhattacharyya, Anirban Krishna; Ziemann, Volker; Ruber, Roger; Goryashko, Vitaliy

2015-01-01

The radio frequency cavities, used to accelerate charged particle beams, need to be charged to their nominal voltage after which the beam can be injected into them. The standard procedure for such cavity filling is to use a step charging profile. However, during initial stages of such a filling process a substantial amount of the total energy is wasted in reflection for superconducting cavities because of their extremely narrow bandwidth. The paper presents a novel strategy to charge cavities, which reduces total energy reflection. We use variational calculus to obtain analytical expression for the optimal charging profile. Energies, reflected and required, and generator peak power are also compared between the charging schemes and practical aspects (saturation, efficiency and gain characteristics) of power sources (tetrodes, IOTs and solid state power amplifiers) are also considered and analysed. The paper presents a methodology to successfully identify the optimal charging scheme for different power sources to minimize total energy requirement.

Influence of tribological additives on friction and impact performance of injection moulded polyacetal

DEFF Research Database (Denmark)

Laursen, Jens Lolle; Sivebæk, Ion Marius; Christoffersen, L.W.

2009-01-01

Tribological additives are used to improve frictional properties of injection moulded thermoplastics. The additives might however also affect the mechanical properties of the material. The influence of processing conditions on both frictional and mechanical properties is highly relevant in the de......Tribological additives are used to improve frictional properties of injection moulded thermoplastics. The additives might however also affect the mechanical properties of the material. The influence of processing conditions on both frictional and mechanical properties is highly relevant...... in the development of tribologically modified grades. In the present study we investigate how two commonly used tribological additives, polydimethylsiloxane and polytetrafluoroethylene, affect friction and impact properties of polyacetal (polyoxymethylene). A new injection mould provides test specimens for both...

Charged particle confinement in magnetic mirror

International Nuclear Information System (INIS)

Bora, D.; John, P.I.; Saxena, Y.C.; Varma, R.K.

1982-01-01

The behaviour of single charged particle trapped in a magnetic mirror has been investigated experimentally. The particle injected off axis and trapped in a magnetic mirror, leak out of the mirror with the leakage characterized by multiple decay times. The observed decay times are in good agreement with predictions of a ''wave mechanical like'' model by Varma, over a large range of relevant parameters. (author)

Electron injection in diodes with field emission

International Nuclear Information System (INIS)

Denavit, J.; Strobel, G.L.

1986-01-01

This paper presents self-consistent steady-state solutions of the space charge, transmitted current, and return currents in diodes with electron injection from the cathode and unlimited field emission of electrons and ions from both electrodes. Time-dependent particle simulations of the diode operation confirm the analytical results and show how these steady states are reached. The results are applicable to thermionic diodes and to photodiodes

Heating of toroidal plasmas by neutral injection

International Nuclear Information System (INIS)

Stix, T.H.

1971-08-01

This paper presents a brief review of the physics of ion acceleration, charge exchange and ionization, trajectories for fast ions in toroidal magnetic fields, and fast-ion thermalization. The injection of fast atoms is found to be a highly competitive method both for heating present-day experimental toroidal plasmas and for bringing full-scale toroidal CTR plasmas to low-density ignition. 13 refs., 9 figs

Injection and temporary capture of a charged particle beam in an open magnetic configuration. Optimization of the configuration. Case of cylindrical symmetry: A mirror machine; Etude de l'injection et de la capture temporaire d'un faisceau de particules chargees dans une configuration magnetique ouverte. Optimisation de la configuration. Cas de la symetrie de revolution: Machine a miroirs

Energy Technology Data Exchange (ETDEWEB)

Capdequi-Peyranere, P [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

1966-12-01

A study has been made of a new method of transverse injection of charged particles into a magnetic mirror configuration. This injection scheme permits the penetration and temporary capture by non-adiabatic effect of a particle beam of approximately 1 cm{sup 2} cross-section. A theoretical study of the injection and capture is made in the approximation that space charge is negligible. The original programs for IBM 7094 computer calculations are described; these programs were used to obtain an optimization of the configuration. The results of a statistical numerical study of the optimum configuration are then given. This study indicates that, if the energy of the particles of the beam is about 1 per cent greater than a minimum penetration energy, the entire beam can be captured with an average capture length of 100 meters (50 reflections between the two mirrors). If the energy is about 4 per cent greater than the minimum penetration energy, the capture length is reduced to 40 meters. We have studied the distribution of energy transverse and longitudinal with the magnetic field for the population of captured particles. For the cases of injected molecular hydrogen ions or heavy CH{sub 4}{sup +} ions, a study is made of the capture time of protons resulting from the dissociation of the ions by collisions with the neutral gas. Finally, we describe a model experiment using electrons designed to provide an experimental verification of the capture of the primary beam. (author) [French] On etudie un nouveau schema d'injection transversale de particules chargees dans une configuration magnetique a miroirs. Ce mode d'injection permet la penetration et la capture temporaire par effet non adiabatique d'un faisceau de particules presentant une section de l'ordre de 1 cm{sup 2}. Une etude theorique du probleme de l'injection et de la capture est faite en supposant la charge d'espace negligeable. On decrit des programmes originaux de calcul sur ordinateur IBM 7094 permettant l

Charge transport properties of CdMnTe radiation detectors

Energy Technology Data Exchange (ETDEWEB)

Kim K.; Rafiel, R.; Boardman, M.; Reinhard, I.; Sarbutt, A.; Watt, G.; Watt, C.; Uxa, S.; Prokopovich, D.A.; Belas, E.; Bolotnikov, A.E.; James, R.B.

2012-04-11

Growth, fabrication and characterization of indium-doped cadmium manganese telluride (CdMnTe)radiation detectors have been described. Alpha-particle spectroscopy measurements and time resolved current transient measurements have yielded an average charge collection efficiency approaching 100 %. Spatially resolved charge collection efficiency maps have been produced for a range of detector bias voltages. Inhomogeneities in the charge transport of the CdMnTe crystals have been associated with chains of tellurium inclusions within the detector bulk. Further, it has been shown that the role of tellurium inclusions in degrading chargecollection is reduced with increasing values of bias voltage. The electron transit time was determined from time of flight measurements. From the dependence of drift velocity on applied electric field the electron mobility was found to be n = (718 55) cm2/Vs at room temperature.

Effect of Titanium Dioxide Dopping on Charge Trapping in ...

African Journals Online (AJOL)

The charge storage properties of corona charged pure and TiO2 doped polystyrene (PS) films have been studied. Thermally stimulated charge decay and open circuit thermally stimulated charges were measured. A half-value charge decay temperature T1/2 ∼ 140oC is optimum at 3 wt % TiO2 doping. This implies that ...

Thermodynamic properties of charged three-dimensional black holes in the scalar-tensor gravity theory

Science.gov (United States)

Dehghani, M.

2018-02-01

Making use of the suitable transformation relations, the action of three-dimensional Einstein-Maxwell-dilaton gravity theory has been obtained from that of scalar-tensor modified gravity theory coupled to the Maxwell's electrodynamics as the matter field. Two new classes of the static three-dimensional charged dilatonic black holes, as the exact solutions to the coupled scalar, electromagnetic and gravitational field equations, have been obtained in the Einstein frame. Also, it has been found that the scalar potential can be written in the form of a generalized Liouville-type potential. The conserved black hole charge and masses as well as the black entropy, temperature, and electric potential have been calculated from the geometrical and thermodynamical approaches, separately. Through comparison of the results arisen from these two alternative approaches, the validity of the thermodynamical first law has been proved for both of the new black hole solutions in the Einstein frame. Making use of the canonical ensemble method, a black hole stability or phase transition analysis has been performed. Regarding the black hole heat capacity, with the black hole charge as a constant, the points of type-1 and type-2 phase transitions have been determined. Also, the ranges of the black hole horizon radius at which the Einstein black holes are thermally stable have been obtained for both of the new black hole solutions. Then making use of the inverse transformation relations, two new classes of the string black hole solutions have been obtained from their Einstein counterpart. The thermodynamics and thermal stability of the new string black hole solutions have been investigated. It has been found that thermodynamic properties of the new charged black holes are identical in the Einstein and Jordan frames.