Marenich, Aleksandr V; Cramer, Christopher J; Truhlar, Donald G
2013-08-13
We present a new kind of treatment of the solute-solvent dispersion contribution to the free energy of solvation using a solvation model with state-specific polarizability (SMSSP). To evaluate the solute-solvent dispersion contribution, the SMSSP model utilizes only two descriptors, namely, the spherically averaged dipole polarizability of the solute molecule (either in its ground or excited electronic state) and the refractive index of the solvent. The model was parametrized over 643 ground-state solvation free energy data for 231 solutes in 14 nonpolar, non-hydrogen-bonding solvents. We show that the SMSSP model is applicable to solutes in both the ground and the excited electronic state. For example, in comparison to available experimental data, the model yields qualitatively accurate predictions of the solvatochromic shifts for a number of systems where solute-solvent dispersion is the dominant contributor to the shift.
Navrotskaya, Irina; Soudackov, Alexander V; Hammes-Schiffer, Sharon
2008-06-28
An extension of the Anderson-Newns-Schmickler model for electrochemical proton-coupled electron transfer (PCET) is presented. This model describes reactions in which electron transfer between a solute complex in solution and an electrode is coupled to proton transfer within the solute complex. The model Hamiltonian is derived in a basis of electron-proton vibronic states defined within a double adiabatic approximation for the electrons, transferring proton, and bath modes. The interaction term responsible for electronic transitions between the solute complex and the electrode depends on the proton donor-acceptor vibrational mode within the solute complex. This model Hamiltonian is used to derive the anodic and cathodic rate constants for nonadiabatic electrochemical PCET. The derivation is based on the master equations for the reduced density matrix of the electron-proton subsystem, which includes the electrons of the solute complex and the electrode, as well as the transferring proton. The rate constant expressions differ from analogous expressions for electrochemical electron transfer because of the summation over electron-proton vibronic states and the dependence of the couplings on the proton donor-acceptor vibrational motion. These differences lead to additional contributions to the total reorganization energy, an additional exponential temperature-dependent prefactor, and a temperature-dependent term in the effective activation energy that has different signs for the anodic and cathodic processes. This model can be generalized to describe both nonadiabatic and adiabatic electrochemical PCET reactions and provides the framework for the inclusion of additional effects, such as the breaking and forming of other chemical bonds.
Valence electron structure of the（ZrTi）B2 solid solutions calculated by the three models
Institute of Scientific and Technical Information of China (English)
无
2009-01-01
The Zr-rich(Zr0.8Ti0.2)B2 and the Ti-rich(Ti0.8Zr0.2)B2 solid solutions are formed when TiB2 and ZrB2 are hot-pressed.To forecast the properties of the two solid solutions,their valence electron structure was analyzed based on the empirical electron theory(EET) of solids and molecules.We used three different models,the average atom model,the average cell model and the real cell model,and compared with the calculation results from the three models.In the real cell model,the lattice constants of the solid solu-tions were supposed to be changed or unchanged.The results showed that different models could only result in slight change in the hybridization levels of the metal atoms in the two solid solutions and little difference between the calculation values.However,they can not change the variant trend of the va-lence electron structure nor the properties of the solid solutions.Thus,the three models and the methods are appropriate and the calculation results are reasonable and consistent.
Valence electron structure of the (ZrTi)B2 solid solutions calculated by the three models
Institute of Scientific and Technical Information of China (English)
LI JinPing; HAN JieCai; MENG SongHe; WANG BaoLin
2009-01-01
The Zr-rich (Zr0.8Ti0.2)B2 and the Ti-rich Zr0.8Ti0.2)B2 solid solutions are formed when TiB2 and ZrB2 are hot-pressed. To forecast the properties of the two solid solutions, their valence electron structure was analyzed based on the empirical electron theory (EET) of solids and molecules. We used three differen tmodels, the average atom model, the average cell model and the real cell model, and compared with the calculation results from the three models. In the real cell model, the lattice constants of the solid solu-tions were supposed to be changed or unchanged. The results showed that different models could only result in slight change in the hybridization levels of the metal atoms in the two solid solutions and little difference between the calculation values. However, they can not change the variant trend of the va-lence electron structure nor the properties of the solid solutions. Thus, the three models and the methods are appropriate and the calculation results are reasonable and consistent.
Iuchi, Satoru
2012-02-14
A simple model electronic Hamiltonian to describe the potential energy surfaces of several low-lying d-d states of the [Fe(bpy)(3)](2+) complex is developed for use in molecular dynamics (MD) simulation studies. On the basis of a method proposed previously for first-row transition metal ions in aqueous solution, the model Hamiltonian is constructed using density functional theory calculations for the lowest singlet and quintet states. MD simulations are then carried out for the two spin states in aqueous solution in order to examine the performance of the model Hamiltonian. The simulation results indicate that the present model electronic Hamiltonian reasonably describes the potential energy surfaces of the two spin states of the aqueous [Fe(bpy)(3)](2+) system, while retaining sufficient simplicity for application in simulation studies on excited state dynamics.
Mortuza, S. M.; Taufique, M. F. N.; Banerjee, Soumik
2017-02-01
The power conversion efficiency (PCE) of planar perovskite solar cells (PSCs) has reached up to ∼20%. However, structural and chemicals defects that lead to hysteresis in the perovskite based thin film pose challenges. Recent work has shown that thin films of [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) deposited on the photo absorption layer, using solution processing techniques, minimize surface pin holes and defects thereby increasing the PCE. We developed and employed a multiscale model based on molecular dynamics (MD) and kinetic Monte Carlo (kMC) to establish a relationship between deposition rate and surface coverage on perovskite surface. The MD simulations of PCBMs dispersed in chlorobenzene, sandwiched between (110) perovskite substrates, indicate that PCBMs are deposited through anchoring of the oxygen atom of carbonyl group to the exposed lead (Pb) atom of (110) perovskite surface. Based on rates of distinct deposition events calculated from MD, kMC simulations were run to determine surface coverage at much larger time and length scales than accessible by MD alone. Based on the model, a generic relationship is established between deposition rate of PCBMs and surface coverage on perovskite crystal. The study also provides detailed insights into the morphology of the deposited film.
Analytic solution for a quartic electron mirror
Energy Technology Data Exchange (ETDEWEB)
Straton, Jack C., E-mail: straton@pdx.edu
2015-01-15
A converging electron mirror can be used to compensate for spherical and chromatic aberrations in an electron microscope. This paper presents an analytical solution to a diode (two-electrode) electrostatic mirror including the next term beyond the known hyperbolic shape. The latter is a solution of the Laplace equation to second order in the variables perpendicular to and along the mirror's radius (z{sup 2}−r{sup 2}/2) to which we add a quartic term (kλz{sup 4}). The analytical solution is found in terms of Jacobi cosine-amplitude functions. We find that a mirror less concave than the hyperbolic profile is more sensitive to changes in mirror voltages and the contrary holds for the mirror more concave than the hyperbolic profile. - Highlights: • We find the analytical solution for electron mirrors whose curvature has z4 dependence added to the usual z{sup 2} – r{sup 2}/2 terms. • The resulting Jacobi cosine-amplitude function reduces to the well-known cosh solution in the limit where the new term is 0. • This quartic term gives a mirror designer additional flexibility for eliminating spherical and chromatic aberrations. • The possibility of using these analytical results to approximately model spherical tetrode mirrors close to axis is noted.
Marenich, Aleksandr V; Cramer, Christopher J; Truhlar, Donald G
2009-05-07
We present a new continuum solvation model based on the quantum mechanical charge density of a solute molecule interacting with a continuum description of the solvent. The model is called SMD, where the "D" stands for "density" to denote that the full solute electron density is used without defining partial atomic charges. "Continuum" denotes that the solvent is not represented explicitly but rather as a dielectric medium with surface tension at the solute-solvent boundary. SMD is a universal solvation model, where "universal" denotes its applicability to any charged or uncharged solute in any solvent or liquid medium for which a few key descriptors are known (in particular, dielectric constant, refractive index, bulk surface tension, and acidity and basicity parameters). The model separates the observable solvation free energy into two main components. The first component is the bulk electrostatic contribution arising from a self-consistent reaction field treatment that involves the solution of the nonhomogeneous Poisson equation for electrostatics in terms of the integral-equation-formalism polarizable continuum model (IEF-PCM). The cavities for the bulk electrostatic calculation are defined by superpositions of nuclear-centered spheres. The second component is called the cavity-dispersion-solvent-structure term and is the contribution arising from short-range interactions between the solute and solvent molecules in the first solvation shell. This contribution is a sum of terms that are proportional (with geometry-dependent proportionality constants called atomic surface tensions) to the solvent-accessible surface areas of the individual atoms of the solute. The SMD model has been parametrized with a training set of 2821 solvation data including 112 aqueous ionic solvation free energies, 220 solvation free energies for 166 ions in acetonitrile, methanol, and dimethyl sulfoxide, 2346 solvation free energies for 318 neutral solutes in 91 solvents (90 nonaqueous
Institute of Scientific and Technical Information of China (English)
王为忠; 姚凯伦
2002-01-01
Using an exact diagonalization method, we study an extended Hubbard model with an electron-lattice interaction for an organic ferromagnetic chain with radical coupling. The result shows that the ferromagnetic ground state originates from the antiferromagnetic correlation between adjoining sites, which is enhanced by the on-site e-e repulsion. The intersite e-e repulsion induces the inhomogeneous distribution of the charge density. The dimerization is decreased by the e-e interaction and the radical coupling. The electron--lattice interaction and the radical coupling can transfer the spin density and charge density between the main chain and the radicals.
Paloma, Cynthia S.
The plasma electron temperature (Te) plays a critical role in a tokamak nu- clear fusion reactor since temperatures on the order of 108K are required to achieve fusion conditions. Many plasma properties in a tokamak nuclear fusion reactor are modeled by partial differential equations (PDE's) because they depend not only on time but also on space. In particular, the dynamics of the electron temperature is governed by a PDE referred to as the Electron Heat Transport Equation (EHTE). In this work, a numerical method is developed to solve the EHTE based on a custom finite-difference technique. The solution of the EHTE is compared to temperature profiles obtained by using TRANSP, a sophisticated plasma transport code, for specific discharges from the DIII-D tokamak, located at the DIII-D National Fusion Facility in San Diego, CA. The thermal conductivity (also called thermal diffusivity) of the electrons (Xe) is a plasma parameter that plays a critical role in the EHTE since it indicates how the electron temperature diffusion varies across the minor effective radius of the tokamak. TRANSP approximates Xe through a curve-fitting technique to match experimentally measured electron temperature profiles. While complex physics-based model have been proposed for Xe, there is a lack of a simple mathematical model for the thermal diffusivity that could be used for control design. In this work, a model for Xe is proposed based on a scaling law involving key plasma variables such as the electron temperature (Te), the electron density (ne), and the safety factor (q). An optimization algorithm is developed based on the Sequential Quadratic Programming (SQP) technique to optimize the scaling factors appearing in the proposed model so that the predicted electron temperature and magnetic flux profiles match predefined target profiles in the best possible way. A simulation study summarizing the outcomes of the optimization procedure is presented to illustrate the potential of the
Energy Technology Data Exchange (ETDEWEB)
Fukuda, Ryoichi, E-mail: fukuda@ims.ac.jp; Ehara, Masahiro [Institute for Molecular Science and Research Center for Computational Science, 38 Nishigo-naka, Myodaiji, Okazaki, 444-8585 (Japan); Elements Strategy Initiative for Catalysts and Batteries (ESICB), Kyoto University Katsura, Kyoto 615-8520 (Japan)
2015-12-31
The effects from solvent environment are specific to the electronic states; therefore, a computational scheme for solvent effects consistent with the electronic states is necessary to discuss electronic excitation of molecules in solution. The PCM (polarizable continuum model) SAC (symmetry-adapted cluster) and SAC-CI (configuration interaction) methods are developed for such purposes. The PCM SAC-CI adopts the state-specific (SS) solvation scheme where solvent effects are self-consistently considered for every ground and excited states. For efficient computations of many excited states, we develop a perturbative approximation for the PCM SAC-CI method, which is called corrected linear response (cLR) scheme. Our test calculations show that the cLR PCM SAC-CI is a very good approximation of the SS PCM SAC-CI method for polar and nonpolar solvents.
Mennucci, Benedetta; Cappelli, Chiara; Guido, Ciro Achille; Cammi, Roberto; Tomasi, Jacopo
2009-04-02
This paper provides an overview of recent research activities concerning the quantum-mechanical description of structures and properties of electronically excited chromophores in solution. The focus of the paper is on a specific approach to include solvent effects, namely the polarizable continuum model (PCM). Such a method represents an efficient strategy if coupled to proper quantum-mechanical descriptions such as the time-dependent density functional theory (TDDFT). As a result, the description of molecules in the condensed phase can be extended to excited states still maintaining the computational efficiency and the physical reliability of the ground-state calculations. The most important theoretical and computational aspects of the coupling between PCM and TDDFT are presented and discussed together with an example of application to the study of the low-lying electronic excited states of push-pull chromophores in different solvents.
Vibrationally Resolved Electron Transfer Rates in Solution
Spears, Kenneth G.
2002-03-01
We have re-examined our earlier report of electron transfer in the [Co(Cp)_2|V(CO)_6] radical-pair using ultrafast infrared transient absorption spectroscopy in room temperature solutions. The radical-pair is created from the [Co(Cp)_2^+|V(CO)_6^-] ion-pair by ultrafast visible charge-transfer excitation. Transient absorption experiments with ps time constants. A small ET component with a 75 ps time constant is due to some separation and reformation of the radical-pairs. Transient absorption experiments monitoring the recovery of the ion-pair state shows that both fast components are due to ET rather than some other vibrational relaxation (VR) process in the radical state. We analyze the visible charge-transfer band and assign the two fast ET decay times to two ion-pair contact geometries with absorption origins different by about 1250 ± 350 cm-1. For excitation at 800 and 700 nm the 700 fs ET lifetime depends on the vibrational quantum state of the nontotally symmetric CO stretch in the V(CO)6 radical, where the lifetime decreases by 10% for the first vibrational quantum and 45% for the second quantum. There is no quantum effect for the second ion-pair geometry with a 5 ps ET lifetime. Standard ET rate models cannot explain the rate dependence upon vibrational quantum state for a nontotally symmetric vibration, and it may arise from a breakdown of the Condon approximation. We also report rates for IVR of CO stretching modes and for VR of low frequency vibrations. At excitation wavelengths of 620 and 555 nm there is sufficient internal vibrational energy in low-frequency vibrations to cause geometric inter-conversion between energetically similar Jahn-Teller geometries in the V(CO)6 radical. This process creates a 200 fs rise time for the V(CO)6 radical species to assume a stable geometry, which requires VR of low frequency vibrations to the solvent. These results demonstrate that earlier ET measurements from our group on the same molecule had insufficient time
Solution processed aluminum paper for flexible electronics.
Lee, Hye Moon; Lee, Ha Beom; Jung, Dae Soo; Yun, Jung-Yeul; Ko, Seung Hwan; Park, Seung Bin
2012-09-11
As an alternative to vacuum deposition, preparation of highly conductive papers with aluminum (Al) features is successfully achieved by the solution process consisting of Al precursor ink (AlH(3){O(C(4)H(9))(2)}) and low temperature stamping process performed at 110 °C without any serious hydroxylation and oxidation problems. Al features formed on several kinds of paper substrates (calendar, magazine, and inkjet printing paper substrates) are less than ~60 nm thick, and their electrical conductivities were found to be as good as thermally evaporated Al film or even better (≤2 Ω/□). Strong adhesion of Al features to paper substrates and their excellent flexibility are also experimentally confirmed by TEM observation and mechanical tests, such as tape and bending tests. The solution processed Al features on paper substrates show different electrical and mechanical performance depending on the paper type, and inkjet printing paper is found to be the best substrate with high and stable electrical and mechanical properties. The Al conductive papers produced by the solution process may be applicable in disposal paper electronics.
Manzoni, Vinícius; Lyra, Marcelo L; Coutinho, Kaline; Canuto, Sylvio
2011-10-14
A combination of the polarizable continuum model (PCM) and the hybrid quantum mechanics/molecular mechanics (QM/MM) methodology, PCM-MM/QM, is used to include the solute electronic polarization and then study the solvent effects on the low-lying n→π(∗) excitation energy and the (15)N nuclear magnetic shielding of pyrazine and pyridazine in aqueous environment. The results obtained with PCM-MM/QM are compared with two other procedures, i.e., the conventional PCM and the iterative and sequential QM/MM (I-QM/MM). The QM calculations are made using density functional theory in the three procedures. For the excitation energies, the time-dependent B3LYP/6-311+G(d) model is used. For the magnetic shielding, the B3LYP/aug-pcS2(N)/pcS2(C,O,H) is used with the gauge-including atomic orbitals. In both cases, i.e., PCM-MM/QM and I-QM/MM, that use a discrete model of the solvent, the solute is surrounded by a first shell of explicit water molecules embedded by an electrostatic field of point charges for the outer shells. The best results are obtained including 28 explicit water molecules for the spectral calculations and 9 explicit water molecules for the magnetic shielding. Using the PCM-MM/QM methodology the results for the n→π(∗) excitation energies of pyridazine and pyrazine are 32,070 ± 80 cm(-1) and 32,675 ± 60 cm(-1), respectively, in good agreement with the corresponding I-MM/QM results of 32,540 ± 80 cm(-1) and 32,710 ± 60 cm(-1) and the experimental results of 33,450-33,580 cm(-1) and 32,700-33,300 cm(-1). For the (15)N magnetic shielding, the corresponding numbers for the gas-water shifts obtained with PCM-MM/QM are 47.4 ± 1.3 ppm for pyridazine and 19.7 ± 1.1 ppm for pyrazine, compared with the I-QM/MM values of 53.4 ± 1.3 ppm and 19.5 ± 1.2 ppm and the experimental results of 42-54 ppm and 17-22 ppm, respectively. The agreement between the two procedures is found to be very good and both are in agreement with the experimental values. PCM
Energy Technology Data Exchange (ETDEWEB)
Setoguchi, T.; Manchu, Y.; Katsumata, M. [Toshiba Corp., Tokyo (Japan)
2000-04-01
Toshiba provides a range of information technology (IT) solutions called SmartEC Solution, which includes business-to-business electronic commerce systems and services based on international standards and industrial know-how, especially our electronic data interchange (EDI) know-how as a manufacturer. These IT solutions are supplied as services covering strategy planning, system integration, and application service provider based on five types of business-to-business electronic commerce. (author)
Electronic states of graphene nanoribbons and analytical solutions
Directory of Open Access Journals (Sweden)
Katsunori Wakabayashi, Ken-ichi Sasaki, Takeshi Nakanishi and Toshiaki Enoki
2010-01-01
Full Text Available Graphene is a one-atom-thick layer of graphite, where low-energy electronic states are described by the massless Dirac fermion. The orientation of the graphene edge determines the energy spectrum of π-electrons. For example, zigzag edges possess localized edge states with energies close to the Fermi level. In this review, we investigate nanoscale effects on the physical properties of graphene nanoribbons and clarify the role of edge boundaries. We also provide analytical solutions for electronic dispersion and the corresponding wavefunction in graphene nanoribbons with their detailed derivation using wave mechanics based on the tight-binding model. The energy band structures of armchair nanoribbons can be obtained by making the transverse wavenumber discrete, in accordance with the edge boundary condition, as in the case of carbon nanotubes. However, zigzag nanoribbons are not analogous to carbon nanotubes, because in zigzag nanoribbons the transverse wavenumber depends not only on the ribbon width but also on the longitudinal wavenumber. The quantization rule of electronic conductance as well as the magnetic instability of edge states due to the electron–electron interaction are briefly discussed.
Boltzmann-Electron Model in Aleph.
Energy Technology Data Exchange (ETDEWEB)
Hughes, Thomas Patrick; Hooper, Russell
2014-11-01
We apply the Boltzmann-electron model in the electrostatic, particle-in-cell, finite- element code Aleph to a plasma sheath. By assuming a Boltzmann energy distribution for the electrons, the model eliminates the need to resolve the electron plasma fre- quency, and avoids the numerical "grid instability" that can cause unphysical heating of electrons. This allows much larger timesteps to be used than with kinetic electrons. Ions are treated with the standard PIC algorithm. The Boltzmann-electron model re- quires solution of a nonlinear Poisson equation, for which we use an iterative Newton solver (NOX) from the Trilinos Project. Results for the spatial variation of density and voltage in the plasma sheath agree well with an analytic model
Electronic Reference Library: Silverplatter's Database Networking Solution.
Millea, Megan
Silverplatter's Electronic Reference Library (ERL) provides wide area network access to its databases using TCP/IP communications and client-server architecture. ERL has two main components: The ERL clients (retrieval interface) and the ERL server (search engines). ERL clients provide patrons with seamless access to multiple databases on multiple…
SOFTWARE SOLUTIONS FOR ARDL MODELS
Directory of Open Access Journals (Sweden)
Nicolae-Marius JULA
2015-07-01
Full Text Available VAR type models can be used only for stationary time series. Causality analyses through econometric models need that series to have the same integrated order. Usually, when constraining the series to comply these restrictions (e.g. by differentiating, economic interpretation of the outcomes may become difficult. Recent solution for mitigating these problems is the use of ARDL (autoregressive distributed lag models. We present implementation in E-Views of these models and we test the impact of exchange rate on consumer price index.
Evaluation of Cooling Solutions for Outdoor Electronics
Wankhede, Mahendra; Goswami, A; Mahajan, S D
2008-01-01
The thermal management of an outdoor electronic enclosure can be quite challenging due to the additional thermal load from the sun and the requirement of having an air-sealed enclosure. It is essential to consider the effect of solar heating loads in the design process; otherwise, it can shorten the life expectancy of the electronic product or lead to catastrophic failure. In this paper we analyze and compare the effectiveness of different cooling techniques used for outdoor electronics. Various cooling techniques were compared like special coatings and paints on the outer surface, radiation shields, double-walled vented enclosures, fans for internal air circulation and air-to-air heat exchangers. A highly simplified, typical outdoor system was selected for this study measuring approximately 300x300x400 mm (WxLxH). Solar radiation was incident on 3 sides of the enclosure. There were 8 equally spaced PCBs inside the enclosure dissipating 12.5W each uniformly (100 watts total). A computational fluid dynamics (C...
Löytynoja, T; Niskanen, J; Jänkälä, K; Vahtras, O; Rinkevicius, Z; Ågren, H
2014-11-20
Using ethanol-water solutions as illustration, we demonstrate the capability of the hybrid quantum mechanics/molecular mechanics (QM/MM) paradigm to simulate core photoelectron spectroscopy: the binding energies and the chemical shifts. An integrated approach with QM/MM binding energy calculations coupled to preceding molecular dynamics sampling is adopted to generate binding energies averaged over the solute-solvent configurations available at a particular temperature and pressure and thus allowing for a statistical assessment with confidence levels for the final binding energies. The results are analyzed in terms of the contributions in the molecular mechanics model-electrostatic, polarization, and van der Waals-with atom or bond granulation of the corresponding MM charge and polarizability force-fields. The role of extramolecular charge transfer screening of the core-hole and explicit hydrogen bonding is studied by extending the QM core to cover the first solvation shell. The results are compared to those obtained from pure electrostatic and polarizable continuum models. Particularly, the dependence of the carbon 1s binding energies with respect to the ethanol concentration is studied. Our results indicate that QM/MM can be used as an all-encompassing model to study photoelectron binding energies and chemical shifts in solvent environments.
Electronic structure and UV spectrum of fenofibrate in solutions.
Le, Yuan; Chen, Jian-Feng; Pu, Min
2008-06-24
The structure and UV spectra of fenofibrate have been evaluated in gas phase and in solutions using time dependent density functional theory (TDDFT) method at the B3LYP/6-31G(d), B3LYP/6-311G(d,p) and B3LYP/6-311++G(d,p) levels. The solvent effects have been taken into account based on the polarizable continuum model (PCM). The computed results appear that the introduction of dielectric medium has slight effect on the molecular geometry of fenofibrate. There is one allowed excited state presenting the strongest oscillator strength in the UV region, which is associated with the HOMO-->LUMO and HOMO-1-->LUMO transition both in gas phase and in solutions. The prediction of the lambda(max) in THF, ethanol and DMSO is 285 nm, 286 nm and 287 nm, respectively, which are in a good agreement with experimental data of 284 nm, 285 nm and 288 nm. The results demonstrate that TDDFT-PCM is a useful tool for study of the electronic absorption in solutions.
Energy Technology Data Exchange (ETDEWEB)
Hasani, Masoumeh [Faculty of Chemistry, Bu-Ali Sina University, Mahdieh, Hamedan, 65174 (Iran, Islamic Republic of)], E-mail: hasani@basu.ac.ir; Shariati-Rad, Masoud [Faculty of Chemistry, Bu-Ali Sina University, Mahdieh, Hamedan, 65174 (Iran, Islamic Republic of); Abdollahi, Hamid [Department of Chemistry, Institute for Advanced Studies in Basic Sciences, Zanjan (Iran, Islamic Republic of)
2009-03-23
Kinetics of electron donor-acceptor (EDA) complex formation of imipramine and 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) was investigated spectrophotometrically in acetonitrile, 1,2-dichloroethane, and chloroform solutions using soft- and hard-modelling approaches. From the results of exploratory analysis of kinetic data and the spectral changes by soft-modelling approaches, evolving factor analysis (EFA) and orthogonal projection approach (OPA), a consecutive two-steps reaction with two intermediates was proposed for the process in acetonitrile and 1,2-dichloroethane media and one with a single intermediate in chloroform solution. Secondly, by applying, multivariate nonlinear least squares hard-modelling approach on the collected experimental kinetic data matrix, the nonlinear parameters (rate constants) as well as the linear parameters (spectral profiles) were obtained by fitting the collected experimental kinetic data matrix to the proposed model. Small values of standard deviation in the resulting parameters and sum of squares of the residuals (ssq) obtained showed the proper selection of the model. Furthermore, the values of lack of fit and percent of explained variance confirmed the correct identified models. Identification of the model with the aid of soft-modelling approaches followed by application of the hard-modelling approaches decreases significantly the rotational ambiguity associated with the obtained concentration and spectral profiles. Variations in the kinetic constants were in complete agreement with the model proposed and the solvent polarities.
Exactly solvable models of strongly correlated electrons
Korepin, Vladimir E
1994-01-01
Systems of strongly correlated electrons are at the heart of recent developments in condensed matter theory. They have applications to phenomena like high-T c superconductivity and the fractional quantum hall effect. Analytical solutions to such models, though mainly limited to one spatial dimension, provide a complete and unambiguous picture of the dynamics involved. This volume is devoted to such solutions obtained using the Bethe Ansatz, and concentrates on the most important of such models, the Hubbard model. The reprints are complemented by reviews at the start of each chapter and an exte
On the solution of the continuity equation for precipitating electrons in solar flares
Energy Technology Data Exchange (ETDEWEB)
Emslie, A. Gordon [Department of Physics and Astronomy, Western Kentucky University, Bowling Green, KY 42101 (United States); Holman, Gordon D. [Code 671, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Litvinenko, Yuri E., E-mail: emslieg@wku.edu, E-mail: gordon.d.holman@nasa.gov [Department of Mathematics, University of Waikato, P. B. 3105, Hamilton (New Zealand)
2014-09-01
Electrons accelerated in solar flares are injected into the surrounding plasma, where they are subjected to the influence of collisional (Coulomb) energy losses. Their evolution is modeled by a partial differential equation describing continuity of electron number. In a recent paper, Dobranskis and Zharkova claim to have found an 'updated exact analytical solution' to this continuity equation. Their solution contains an additional term that drives an exponential decrease in electron density with depth, leading them to assert that the well-known solution derived by Brown, Syrovatskii and Shmeleva, and many others is invalid. We show that the solution of Dobranskis and Zharkova results from a fundamental error in the application of the method of characteristics and is hence incorrect. Further, their comparison of the 'new' analytical solution with numerical solutions of the Fokker-Planck equation fails to lend support to their result. We conclude that Dobranskis and Zharkova's solution of the universally accepted and well-established continuity equation is incorrect, and that their criticism of the correct solution is unfounded. We also demonstrate the formal equivalence of the approaches of Syrovatskii and Shmeleva and Brown, with particular reference to the evolution of the electron flux and number density (both differential in energy) in a collisional thick target. We strongly urge use of these long-established, correct solutions in future works.
High mobility, printable, and solution-processed graphene electronics.
Wang, Shuai; Ang, Priscilla Kailian; Wang, Ziqian; Tang, Ai Ling Lena; Thong, John T L; Loh, Kian Ping
2010-01-01
The ability to print graphene sheets onto large scale, flexible substrates holds promise for large scale, transparent electronics on flexible substrates. Solution processable graphene sheets derived from graphite can form stable dispersions in solutions and are amenable to bulk scale processing and ink jet printing. However, the electrical conductivity and carrier mobilities of this material are usually reported to be orders of magnitude poorer than that of the mechanically cleaved counterpart due to its higher density of defects, which restricts its use in electronics. Here, we show that by optimizing several key factors in processing, we are able to fabricate high mobility graphene films derived from large sized graphene oxide sheets, which paves the way for all-carbon post-CMOS electronics. All-carbon source-drain channel electronics fabricated from such films exhibit significantly improved transport characteristics, with carrier mobilities of 365 cm(2)/(V.s) for hole and 281 cm(2)/(V.s) for electron, measured in air at room temperature. In particular, intrinsic mobility as high as 5000 cm(2)/(V.s) can be obtained from such solution-processed graphene films when ionic screening is applied to nullify the Coulombic scattering by charged impurities.
Gorcester, Jeff; Rananavare, Shankar B.; Freed, Jack H.
1989-05-01
Electron spin-echo (ESE) and two-dimensional electron-electron double resonance (2D ELDOR) experiments have been performed as a function of director orientation and temperature in the smectic A phase of the liquid crystal S2 for the spin-probe PD-tempone(2×10-3 M). Over the entire temperature range studied (288-323 K) we observe significant 2D ELDOR cross peaks only for ΔMI =±1 indicative of 14N spin-relaxation and negligible Heisenberg exchange. From the angular dependent 14N spin-relaxation rates we obtain the dipolar spectral densities at the hyperfine (hf) frequency, whereas from a combination of ESE and 2D ELDOR we obtain the dipolar and Zeeman-dipolar spectral densities at zero frequency. The angular dependent spectral densities were successfully decomposed into their basic components in accordance with theory. The angular dependent spectral densities at the hf frequency are not predicted by a model of anisotropic rotational diffusion in a nematic orienting potential, but are consistent with predictions of a model due to Moro and Nordio of solute rototranslational diffusion in a McMillan-type potential. The angular dependence also indicates that order director fluctuations in the smectic phase are suppressed at frequencies on the order of 10 MHz. An additional contribution to solute reorientation due to cooperative hydrocarbon chain fluctuations is suggested to account for the behavior of the observed spectral densities at zero frequency. An evaluation of the relevance of several other dynamical models to this experimental work is also presented.
El-Wakil, S A; Abd-El-Hamid, H M; Abulwafa, E M
2010-01-01
A rigorous theoretical investigation has been made on electron acoustic wave propagating in unmagnetized collisionless plasma consisting of a cold electron fluid, non-thermal hot electrons and stationary ions. Based on the pseudo-potential approach, large amplitude potential structures and the existence of solitary waves are discussed. The reductive perturbation method has been employed to derive the Korteweg-de Vries (KdV) equation for small but finite amplitude electrostatic waves. An algebraic method with computerized symbolic computation, which greatly exceeds the applicability of the existing tanh, extended tanh methods in obtaining a series of exact solutions of the KdV equation. Numerical studies have been made using plasma parameters close to those values corresponding to the dayside auroral zone reveals different solutions i.e., bell-shaped solitary pulses, rational pulses and solutions with singularity at a finite points which called blowup solutions in addition to the propagation of an explosive pu...
Progress on Analytical Modeling of Coherent Electron Cooling
Energy Technology Data Exchange (ETDEWEB)
Wang, G.; Blaskiewicz, M.; Litvinenko, V.; Webb, S.
2010-05-23
We report recent progresses on analytical studies of Coherent Electron Cooling. The phase space electron beam distribution obtained from the 1D FEL amplifier is applied to an infinite electron plasma model and the electron density evolution inside the kicker is derived. We also investigate the velocity modulation in the modulator and obtain a closed form solution for the current density evolution for infinite homogeneous electron plasma.
Exact Solutions in Nonlocal Linear Models
Vernov, S. Yu.
2008-01-01
A general class of cosmological models driven by a nonlocal scalar field inspired by the string field theory is studied. Using the fact that the considering linear nonlocal model is equivalent to an infinite number of local models we have found an exact special solution of the nonlocal Friedmann equations. This solution describes a monotonically increasing Universe with the phantom dark energy.
New exact solutions in standard inflationary models
Chervon, S V; Shchigolev, V K
1997-01-01
The exact solutions in the standard inflationary model based on the self-interacting scalar field minimally coupled to gravity are considered. The shape's freedom of the self-interacting potential $V(\\phi)$ is postulated to obtain a new set of the exact solutions in the framework of Friedmann-Robertson-Walker Universes. The general solution was found in the case of power law inflation. We obtained new solutions and compared them with obtained ones earlir for the exponential type inflation.
Cosolvent approach for solution-processable electronic thin films.
Lin, Zhaoyang; He, Qiyuan; Yin, Anxiang; Xu, Yuxi; Wang, Chen; Ding, Mengning; Cheng, Hung-Chieh; Papandrea, Benjamin; Huang, Yu; Duan, Xiangfeng
2015-04-28
Low-temperature solution-processable electronic materials are of considerable interest for large-area, low-cost electronics, thermoelectrics, and photovoltaics. Using a soluble precursor and suitable solvent to formulate a semiconductor ink is essential for large-area fabrication of semiconductor thin films. To date, it has been shown that hydrazine can be used as a versatile solvent to process a wide range of inorganic semiconductors. However, hydrazine is highly toxic and not suitable for large-scale manufacturing. Here we report a binary mixed solvent of amine and thiol for effective dispersion and dissolution of a large number of inorganic semiconductors including Cu2S, Cu2Se, In2S3, In2Se3, CdS, SnSe, and others. The mixed solvent is significantly less toxic and safer than hydrazine, while at the same time offering the comparable capability of formulating diverse semiconductor ink with a concentration as high as >200 mg/mL. We further show that such ink material can be readily processed into high-performance semiconducting thin films (Cu2S and Cu2Se) with the highest room-temperature conductivity among solution-based materials. Furthermore, we show that complex semiconductor alloys with tunable band gaps, such as CuIn(S(x)Se(1-x))2 (0 ≤ x ≤ 1), can also be readily prepared by simply mixing Cu2S, Cu2Se, In2S3, and In2Se3 ink solutions in a proper ratio. Our study outlines a general strategy for the formulation of inorganic semiconductor ink for low-temperature processing of large-area electronic thin films on diverse substrates and can greatly impact diverse areas including flexible electronics, thermoelectrics, and photovoltaics.
Disorder solutions of lattice spin models
Batchelor, M. T.; van Leeuwen, J. M. J.
1989-01-01
It is shown that disorder solutions, which have been obtained by different methods, follow from a simple decimation method. The method is put in general form and new disorder solutions are constructed for the Blume-Emery-Griffiths model on a triangular lattice and for Potts and Ising models on square and fcc lattices.
Lattice Model for water-solute mixtures
Furlan, A. P.; Almarza, N. G.; M. C. Barbosa
2016-01-01
A lattice model for the study of mixtures of associating liquids is proposed. Solvent and solute are modeled by adapting the associating lattice gas (ALG) model. The nature of interaction solute/solvent is controlled by tuning the energy interactions between the patches of ALG model. We have studied three set of parameters, resulting on, hydrophilic, inert and hydrophobic interactions. Extensive Monte Carlo simulations were carried out and the behavior of pure components and the excess proper...
1H relaxation dispersion in solutions of nitroxide radicals: Influence of electron spin relaxation
Kruk, D.; Korpała, A.; Kubica, A.; Kowalewski, J.; Rössler, E. A.; Moscicki, J.
2013-03-01
The work presents a theory of nuclear (1H) spin-lattice relaxation dispersion for solutions of 15N and 14N radicals, including electron spin relaxation effects. The theory is a generalization of the approach presented by Kruk et al. [J. Chem. Phys. 137, 044512 (2012)], 10.1063/1.4736854. The electron spin relaxation is attributed to the anisotropic part of the electron spin-nitrogen spin hyperfine interaction modulated by rotational dynamics of the paramagnetic molecule, and described by means of Redfield relaxation theory. The 1H relaxation is caused by electron spin-proton spin dipole-dipole interactions which are modulated by relative translational motion of the solvent and solute molecules. The spectral density characterizing the translational dynamics is described by the force-free-hard-sphere model. The electronic relaxation influences the 1H relaxation by contributing to the fluctuations of the inter-molecular dipolar interactions. The developed theory is tested against 1H spin-lattice relaxation dispersion data for glycerol solutions of 4-oxo-TEMPO-d16-15N and 4-oxo-TEMPO-d16-14N covering the frequency range of 10 kHz-20 MHz. The studies are carried out as a function of temperature starting at 328 K and going down to 290 K. The theory gives a consistent overall interpretation of the experimental data for both 14N and 15N systems and explains the features of 1H relaxation dispersion resulting from the electron spin relaxation.
Electron-beam-induced deposition of gold from aqueous solutions
Energy Technology Data Exchange (ETDEWEB)
Schardein, G; Donev, E U; Hastings, J T, E-mail: hastings@engr.uky.edu [Department of Electrical and Computer Engineering and Center for Nanoscale Science and Engineering (CeNSE), University of Kentucky, Lexington, KY 40506 (United States)
2011-01-07
Focused electron-beam-induced deposition (EBID) using bulk liquid precursors is a novel approach to nanofabrication that has shown improvements in purity compared to EBID with gas-phase precursors. Here we report the first EBID of gold using bulk liquid precursors. We study the differences in gold deposited from three different aqueous solutions containing chloroauric acid (HAuCl{sub 4}), sodium tetrachloroaurate (NaAuCl{sub 4}), and the disulfitoaurate complex ([Au(SO{sub 3}){sub 2}]{sup 3-}). We also examine the dependence of threshold dose upon precursor concentration and demonstrate high-resolution patterning with a pitch as small as 50 nm. Finally, we show that the purity of gold deposited using these liquid precursors is significantly improved in comparison with deposits from metal-organic gaseous precursors.
The quantum Rabi model: solution and dynamics
Xie, Qiongtao; Zhong, Honghua; Batchelor, Murray T.; Lee, Chaohong
2017-03-01
This article presents a review of recent developments on various aspects of the quantum Rabi model. Particular emphasis is given on the exact analytic solution obtained in terms of confluent Heun functions. The analytic solutions for various generalisations of the quantum Rabi model are also discussed. Results are also reviewed on the level statistics and the dynamics of the quantum Rabi model. The article concludes with an introductory overview of several experimental realisations of the quantum Rabi model. An outlook towards future developments is also given.
The quantum Rabi model: solution and dynamics
Xie, Qiongtao; Batchelor, Murray T; Lee, Chaohong
2016-01-01
This article presents a review of recent developments on various aspects of the quantum Rabi model. Particular emphasis is given on the exact analytic solution obtained in terms of confluent Heun functions. The analytic solutions for various generalisations of the quantum Rabi model are also discussed. Results are also reviewed on the level statistics and the dynamics of the quantum Rabi model. The article concludes with an introductory overview of several experimental realisations of the quantum Rabi model. An outlook towards future developments is also given.
Vulnerabilities of Electronics Communication: solution mechanism through script
Directory of Open Access Journals (Sweden)
Arun Kumar Singh
2011-05-01
Full Text Available World trade and related business ventures are more or less dependent on communication. Information content of communication is to be protected as mis-communication or incorrect information may ruin any business prospect. Communication using Internet or any other electronic communication is having various kinds of threat and vulnerability. Information should be packaged for communication in such a way that these vulnerabilities are reduced to a minimum. With the increased use of networked computers for critical systems, network security is attracting increasing attention. This paper focuses on the most common attacks to paralyze computer and network resources, in order to stop essential communication services. The paper provides methods, ways and means for obtaining network traces of malicious traffic and strategies for providing countermeasures. Analysis of packet captured in a network traffic is a common method of deletion of countermeasure of communication based vulnerabilities. Analysis of http based network traffic allows to intercept sensitive information such as the user's name and password. The ideal approach for secured communication is to remove all security flaws from individual hosts. A tradeoff between overheads (computational and business and efficiency of securing mechanism of communication may be achieved by using the script based solutions. This paper presents the communication based vulnerabilities and their script based solution.
Modeling the Quiet Time Outflow Solution in the Polar Cap
Glocer, Alex
2011-01-01
We use the Polar Wind Outflow Model (PWOM) to study the geomagnetically quiet conditions in the polar cap during solar maximum, The PWOM solves the gyrotropic transport equations for O(+), H(+), and He(+) along several magnetic field lines in the polar region in order to reconstruct the full 3D solution. We directly compare our simulation results to the data based empirical model of Kitamura et al. [2011] of electron density, which is based on 63 months of Akebono satellite observations. The modeled ion and electron temperatures are also compared with a statistical compilation of quiet time data obtained by the EISCAT Svalbard Radar (ESR) and Intercosmos Satellites (Kitamura et al. [2011]). The data and model agree reasonably well. This study shows that photoelectrons play an important role in explaining the differences between sunlit and dark results, ion composition, as well as ion and electron temperatures of the quiet time polar wind solution. Moreover, these results provide validation of the PWOM's ability to model the quiet time ((background" solution.
Applied Integer Programming Modeling and Solution
Chen, Der-San; Dang, Yu
2011-01-01
An accessible treatment of the modeling and solution of integer programming problems, featuring modern applications and software In order to fully comprehend the algorithms associated with integer programming, it is important to understand not only how algorithms work, but also why they work. Applied Integer Programming features a unique emphasis on this point, focusing on problem modeling and solution using commercial software. Taking an application-oriented approach, this book addresses the art and science of mathematical modeling related to the mixed integer programming (MIP) framework and
Scaffolding Mathematical Modelling with a Solution Plan
Schukajlow, Stanislaw; Kolter, Jana; Blum, Werner
2015-01-01
In the study presented in this paper, we examined the possibility to scaffold mathematical modelling with strategies. The strategies were prompted using an instrument called "solution plan" as a scaffold. The effects of this step by step instrument on mathematical modelling competency and on self-reported strategies were tested using…
Electron-plasmon model in the electron liquid theory
Directory of Open Access Journals (Sweden)
M.V.Vavrukh
2005-01-01
Full Text Available Here we propose an accurate approach to the description of the electron liquid model in the electron and plasmon terms. Our ideas in the present paper are close to the conception of the collective variables which was developed in the papers of Bohm and Pines. However we use another body of mathematics in the transition to the expanded space of variable particles and plasmons realized by the transition operator. It is evident that in the Random Phase Approximation (RPA, the model which consists of two interactive subsystems of electrons and plasmons is equivalent to the electron liquid model with Coulomb interaction.
Aqueous Solution Vessel Thermal Model Development II
Energy Technology Data Exchange (ETDEWEB)
Buechler, Cynthia Eileen [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
2015-10-28
The work presented in this report is a continuation of the work described in the May 2015 report, “Aqueous Solution Vessel Thermal Model Development”. This computational fluid dynamics (CFD) model aims to predict the temperature and bubble volume fraction in an aqueous solution of uranium. These values affect the reactivity of the fissile solution, so it is important to be able to calculate them and determine their effects on the reaction. Part A of this report describes some of the parameter comparisons performed on the CFD model using Fluent. Part B describes the coupling of the Fluent model with a Monte-Carlo N-Particle (MCNP) neutron transport model. The fuel tank geometry is the same as it was in the May 2015 report, annular with a thickness-to-height ratio of 0.16. An accelerator-driven neutron source provides the excitation for the reaction, and internal and external water cooling channels remove the heat. The model used in this work incorporates the Eulerian multiphase model with lift, wall lubrication, turbulent dispersion and turbulence interaction. The buoyancy-driven flow is modeled using the Boussinesq approximation, and the flow turbulence is determined using the k-ω Shear-Stress-Transport (SST) model. The dispersed turbulence multiphase model is employed to capture the multiphase turbulence effects.
Exact solution of phantom dark energy model
Institute of Scientific and Technical Information of China (English)
Wang Wen-Fu; Shui Zheng-Wei; Tang Bin
2010-01-01
We investigate the phantom dark energy model derived from the scalar field with a negative kinetic term. By assuming a particular relation between the time derivative of the phantom field and the Hubble function, an exact solution of the model is constructed. Absence of the 'big rip' singularity is shown explicitly. We then derive special features of phantom dark energy model and show that its predictions are consistent with all astrophysical observations.
Implementation of electronic data capture systems: barriers and solutions.
Welker, James A
2007-05-01
Although increasing in pace, the conversion to Electronic Data Capture (EDC) has been a slow progression. The use of EDC systems should confer improved data integrity, cost savings and a shorter time to study database closure. This will reduce the time to market and cost of new medications. With the current sentiment of the industry suggesting the cost analysis has been accepted to be in favor of EDC, the likely limitation to disseminated use is an inability to implement these systems. If the leadership at the sponsor, clinical research organization and investigator site is cognizant of the barriers to implementation, they can anticipate and mitigate them prior to the users becoming disgruntled and resistant to the new method of data capture. Once understood, barriers such as user input, technical support, user motivation, regulatory requirements, communication with users, timing of implementation, software installation, graphical user interface, identification of bridgers, patient participation, availability of technology, and costs can be better addressed at the beginning of the implementation process and successfully averted. This review discusses these barriers and potential solutions that can assist the clinical trial industry in achieving more wide-spread EDC use and the resulting improvement in operating efficiencies.
Solution of the Boltzmann Equation for Electrons in Laser-Heated Metals
Pietanza, L. D.; Colonna, G.; Capitelli, M.
2005-05-01
A kinetic study of the electron relaxation dynamic inside a noble metal film (Ag) subjected to a femtosecond laser pulse has been performed. A time dependent numerical algorithm for the solution of the Boltzmann equations for electrons and phonons inside the film has been developped, considering electron-electron and electron-phonon collisions and the laser perturbation. The dependence of electron-electron and electron-phonon characteristic time-scales on the screening parameter values has been investigated. Electron-electron relaxation times are also compared with experimental data obtained through time-resolved two-photon photoemission technique.
Integrated secure solution for electronic healthcare records sharing
Yao, Yehong; Zhang, Chenghao; Sun, Jianyong; Jin, Jin; Zhang, Jianguo
2007-03-01
The EHR is a secure, real-time, point-of-care, patient-centric information resource for healthcare providers. Many countries and regional districts have set long-term goals to build EHRs, and most of EHRs are usually built based on the integration of different information systems with different information models and platforms. A number of hospitals in Shanghai are also piloting the development of an EHR solution based on IHE XDS/XDS-I profiles with a service-oriented architecture (SOA). The first phase of the project targets the Diagnostic Imaging domain and allows seamless sharing of images and reports across the multiple hospitals. To develop EHRs for regional coordinated healthcare, some factors should be considered in designing architecture, one of which is security issue. In this paper, we present some approaches and policies to improve and strengthen the security among the different hospitals' nodes, which are compliant with the security requirements defined by IHE IT Infrastructure (ITI) Technical Framework. Our security solution includes four components: Time Sync System (TSS), Digital Signature Manage System (DSMS), Data Exchange Control Component (DECC) and Single Sign-On (SSO) System. We give a design method and implementation strategy of these security components, and then evaluate the performance and overheads of the security services or features by integrating the security components into an image-based EHR system.
Shushkov, Philip
2013-06-14
We present a derivation of Marcus theory of electron transfer in solution starting from semiclassical instanton theory. The conventional semiclassical instanton theory provides an inadequate description of the electron transfer process in the inverted Marcus regime. This has been attributed to the lack of backscattering in the product region, which is represented as a semi-infinite continuum of states. For electron transfer processes in condensed phase, the electronic states in the acceptor well are bound, which violates the continuum assumption. We show by detailed analysis of the minimum action path of a model system for electron transfer that the proper tunneling coordinate is a delocalized, "bead-count" mode. The tunneling mode is analytically continued in the complex plane as in the traditional derivation. Unlike the traditional analysis where the method of steepest descent is used, the tunneling coordinate is treated as a quasi-zero mode. This feature allows including the influence of backscattering in the acceptor well and leads to the recovery of the Marcus formula for the rate of electron transfer. The results have implications on the performance of ring polymer molecular dynamics for the study of electron transfer dynamics.
Zharkova, V. V.; Dobranskis, R. R.
2016-06-01
In this paper we consider simultaneous analytical solutions of continuity equations for electron beam precipitation (a) in collisional losses and (b) in ohmic losses, or mixed energy losses (MEL) by applying the iterative method to calculate the resulting differential densities at given precipitation depth. The differential densities of precipitating electrons derived from the analytical solutions for MELs reveal increased flattening at energies below 10-30 keV compared to a pure collisional case. This flattening becomes stronger with an increasing precipitation depth turning into a positive slope at greater precipitation depths in the chromosphere resulting in a differential density distribution with maximum that shifts towards higher energies with increase in column depth, while the differential densities combining precipitating and returning electrons are higher at lower energies than those for a pure collisional case. The resulting hard X-ray (HXR) emission produced by the beams with different initial energy fluxes and spectral indices is calculated using the MEL approach for different ratios between the differential densities of precipitating and returning electrons. The number of returning electrons can be even further enhanced by a magnetic mirroring, not considered in the present model, while dominating at lower atmospheric depths where the magnetic convergence and magnitude are the highest. The proposed MEL approach provides an opportunity to account simultaneously for both collisional and ohmic losses in flaring events, which can be used for a quick spectral fitting of HXR spectra and evaluation of a fraction of returning electrons versus precipitating ones. The semi-analytical MEL approach is used for spectral fitting to Reuven High Energy Solar Spectroscopic Imager observations of nine C, M and X class flares revealing a close fit to the observations and good resemblance to numerical FP solutions.
Unger, I; Thürmer, S; Aziz, E F; Cederbaum, L S; Muchová, E; Slavíček, P; Winter, B; Kryzhevoi, N V
2016-01-01
A major goal of many spectroscopic techniques is to provide comprehensive information on the local chemical environment. Electron transfer mediated decay (ETMD) is a sensitive probe of the environment since it is actively involved in this non-local radiationless decay process through electron and energy transfer steps. We report the first experimental observation of ETMD in the liquid phase. Using liquid-jet X-ray photoelectron spectroscopy we explore LiCl aqueous solution, and detect low-energy electrons unambiguously emerging from the ETMD processes of core-ionized Li+. We interpret the experimental results with molecular dynamics and high-level ab initio calculations. By considering various solvation-structure models we show that both water molecules and Cl- anions can participate in ETMD, with each process having its characteristic spectral fingerprint. Different ion associations lead to different spectral shapes. The potential application of the unique sensitivity of the ETMD spectroscopy to the local hy...
Subdaily Earth rotation model and GPS solutions
Panafidina, Natalia; Hugentobler, Urs; Seitz, Manuela
2014-05-01
In this contribution we study the influence of the subdaily Earth rotation model on the GPS solution including station coordinates, satellite orbits and daily Earth rotation parameters (ERPs). The approach used is based on the transformation of GPS normal equation systems: free daily normal equations containing ERPs with 1-hour resolution are used as input data, in this case the high-frequency ERPs can be transformed into tidal terms which then can be fixed to new a priori values, thus changing implicitly the underlying subdaily Earth rotation model. To study the influence of individual tidal terms on the solution we successively changed a priori values for one tidal term in polar motion and compared the resulting solutions for GPS orbits, station coordinates and daily ERPs for a time interval of 13 years. The comparison reveals periodic changes in all estimated parameters with periods depending on the periods of the changed tidal terms. The dynamical reference frame realized by the GPS orbits is also affected: the whole satellite constellation shows periodic orientation variations, and each individual satellite shows periodic changes in the position of the orbit origin. We present a mechanism showing how errors in the subdaily Earth rotation model are propagated into the dynamical reference frame and the estimated parameters. Our model represents a change in one tidal term over one day as the sum of a prograde diurnal wave, a retrograde diurnal wave and an offset and linear drift in x- and y-pole. We demonstrate that this simple model, in conjunction with appropriate constraints, can explain well the observed variations in a one day GPS solution as well as in daily pole rates caused by changes in the subdaily Earth rotation model.
Soliton-like Solutions and Electron Transfer in DNA.
Lakhno, V D
2000-06-01
We consider various mechanisms of long-range electron transfer in DNAwhich enable us to explain recent controversial experiments. We show thatcontinuous super-exchange theory can explain the values of electron rateconstants in short fragments of DNA. The soliton-type electron transfer inlong segments of DNA is also dealt with.
Soliton-like Solutions and Electron Transfer in DNA
Lakhno, V.D.
2000-01-01
We consider various mechanisms of long-range electron transfer in DNAwhich enable us to explain recent controversial experiments. We show thatcontinuous super-exchange theory can explain the values of electron rateconstants in short fragments of DNA. The soliton-type electron transfer inlong segments of DNA is also dealt with.
Structure and aggregation in model tetramethylurea solutions
Energy Technology Data Exchange (ETDEWEB)
Gupta, Rini; Patey, G. N., E-mail: patey@chem.ubc.ca [Department of Chemistry, University of British Columbia, Vancouver, British Columbia V6T 1Z1 (Canada)
2014-08-14
The structure of model aqueous tetramethylurea (TMU) solutions is investigated employing large-scale (32 000, 64 000 particles) molecular dynamics simulations. Results are reported for TMU mole fractions, X{sub t}, ranging from infinite dilution up to 0.07, and for two temperatures, 300 and 330 K. Two existing force fields for TMU-water solutions are considered. These are the GROMOS 53A6 united-atom TMU model combined with SPC/E water [TMU(GROMOS-UA)/W(SPC/E)], and the more frequently employed AMBER03 all-atom force field for TMU combined with the TIP3P water model [TMU(AMBER-AA)/W(TIP3P)]. It is shown that TMU has a tendency towards aggregation for both models considered, but the tendency is significantly stronger for the [TMU(AMBER-AA)/W(TIP3P)] force field. For this model signs of aggregation are detected at X{sub t} = 0.005, aggregation is a well established feature of the solution at X{sub t} = 0.02, and the aggregates increase further in size with increasing concentration. This is in agreement with at least some experimental studies, which report signals of aggregation in the low concentration regime. The TMU aggregates exhibit little structure and are simply loosely ordered, TMU-rich regions of solution. The [TMU(GROMOS-UA)/W(SPC/E)] model shows strong signs of aggregation only at higher concentrations (X{sub t} ≳ 0.04), and the aggregates appear more loosely ordered, and less well-defined than those occurring in the [TMU(AMBER-AA)/W(TIP3P)] system. For both models, TMU aggregation increases when the temperature is increased from 300 to 330 K, consistent with an underlying entropy driven, hydrophobic interaction mechanism. At X{sub t} = 0.07, the extra-molecular correlation length expected for microheterogeneous solutions has become comparable with the size of the simulation cell for both models considered, indicating that even the systems simulated here are sufficiently large only at low concentrations.
Electron beam simulation from gun to collector: Towards a complete solution
Energy Technology Data Exchange (ETDEWEB)
Mertzig, R., E-mail: robert.mertzig@cern.ch; Shornikov, A., E-mail: robert.mertzig@cern.ch; Wenander, F. [CERN, Geneva 23, CH-1211 (Switzerland); Beebe, E.; Pikin, A. [Brookhaven National Lab, Upton, NY 11973 (United States)
2015-01-09
An electron-beam simulation technique for high-resolution complete EBIS/T modelling is presented. The technique was benchmarked on the high compression HEC{sup 2} test-stand with an electron beam current, current density and energy of 10 A, 10 kA/cm{sup 2} and 49.2 keV, and on the immersed electron beam at REXEBIS for electron beam characteristics of 0.4 A, 200 A/cm{sup 2} and 4.5 keV. In both Brillouin-like and immersed beams the electron-beam radius varies from several millimeters at the gun, through some hundreds of micrometers in the ionization region to a few centimeters at the collector over a total length of several meters. We report on our approach for finding optimal meshing parameters, based on the local beam properties such as magnetic field-strength, electron energy and beam radius. This approach combined with dividing the problem domain into sub-domains, and subsequent splicing of the local solutions allowed us to simulate the beam propagation in EBISes from the gun to the collector using a conventional PC in about 24–36 h. Brillouin-like electron beams propagated through the complete EBIS were used to analyze the beam behavior within the collector region. We checked whether elastically reflected paraxial electrons from a Brillouin-like beam will escape from the collector region and add to the loss current. We have also studied the power deposition profiles as function of applied potentials using two electrode geometries for a Brillouin-like beam including the effects of backscattered electrons.
Strong solutions of semilinear matched microstructure models
Escher, Joachim
2011-01-01
The subject of this article is a matched microstructure model for Newtonian fluid flows in fractured porous media. This is a homogenized model which takes the form of two coupled parabolic differential equations with boundary conditions in a given (two-scale) domain in Euclidean space. The main objective is to establish the local well-posedness in the strong sense of the flow. Two main settings are investigated: semi-linear systems with linear boundary conditions and semi-linear systems with nonlinear boundary conditions. With the help of analytic semigoups we establish local well-posedness and investigate the long-time behaviour of the solutions in the first case: we establish global existence and show that solutions converge to zero at an exponential rate.
Modeling Electrolyte Solutions with the extended universal quasichemical (UNIQUAC) Model
DEFF Research Database (Denmark)
Thomsen, Kaj
2005-01-01
The extended universal quasichemical (UNIQUAC) model is a thermodynamic model for solutions containing electrolytes and non-electrolytes. The model is a gibbs excess function consisting of a Debye-Hückel term and a standard UNIQUAC term. The model only requires binary, ion specific interaction...... parameters. A unique choice of standard states makes the model able to reproduce solid-liquid, vapor-liquid, and liquid-liquid phase equilibria as well as thermal properties of electrolyte solutions using one set of parameters....
Modeling Electrolyte Solutions with the extended universal quasichemical (UNIQUAC) Model
DEFF Research Database (Denmark)
Thomsen, Kaj
2005-01-01
The extended universal quasichemical (UNIQUAC) model is a thermodynamic model for solutions containing electrolytes and non-electrolytes. The model is a gibbs excess function consisting of a Debye-Hückel term and a standard UNIQUAC term. The model only requires binary, ion specific interaction...... parameters. A unique choice of standard states makes the model able to reproduce solid-liquid, vapor-liquid, and liquid-liquid phase equilibria as well as thermal properties of electrolyte solutions using one set of parameters....
Modeling of power electronic systems with EMTP
Tam, Kwa-Sur; Dravid, Narayan V.
1989-01-01
In view of the potential impact of power electronics on power systems, there is need for a computer modeling/analysis tool to perform simulation studies on power systems with power electronic components as well as to educate engineering students about such systems. The modeling of the major power electronic components of the NASA Space Station Freedom Electric Power System is described along with ElectroMagnetic Transients Program (EMTP) and it is demonstrated that EMTP can serve as a very useful tool for teaching, design, analysis, and research in the area of power systems with power electronic components. EMTP modeling of power electronic circuits is described and simulation results are presented.
Modeling ion sensing in molecular electronics
Energy Technology Data Exchange (ETDEWEB)
Chen, Caroline J.; Smeu, Manuel, E-mail: manuel.smeu@northwestern.edu; Ratner, Mark A., E-mail: ratner@northwestern.edu [Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208 (United States)
2014-02-07
We examine the ability of molecules to sense ions by measuring the change in molecular conductance in the presence of such charged species. The detection of protons (H{sup +}), alkali metal cations (M{sup +}), calcium ions (Ca{sup 2+}), and hydronium ions (H{sub 3}O{sup +}) is considered. Density functional theory (DFT) is used within the Keldysh non-equilibrium Green's function framework (NEGF) to model electron transport properties of quinolinedithiol (QDT, C{sub 9}H{sub 7}NS{sub 2}), bridging Al electrodes. The geometry of the transport region is relaxed with DFT. The transport properties of the device are modeled with NEGF-DFT to determine if this device can distinguish among the M{sup +} + QDT species containing monovalent cations, where M{sup +} = H{sup +}, Li{sup +}, Na{sup +}, or K{sup +}. Because of the asymmetry of QDT in between the two electrodes, both positive and negative biases are considered. The electron transmission function and conductance properties are simulated for electrode biases in the range from −0.5 V to 0.5 V at increments of 0.1 V. Scattering state analysis is used to determine the molecular orbitals that are the main contributors to the peaks in the transmission function near the Fermi level of the electrodes, and current-voltage relationships are obtained. The results show that QDT can be used as a proton detector by measuring transport through it and can conceivably act as a pH sensor in solutions. In addition, QDT may be able to distinguish among different monovalent species. This work suggests an approach to design modern molecular electronic conductance sensors with high sensitivity and specificity using well-established quantum chemistry.
Energy Technology Data Exchange (ETDEWEB)
Ross, A.B.
1975-06-01
A compilation of rates of reactions of hydrated electrons with other transients and with organic and inorganic solutes in aqueous solution appeared in NSRDS-NBS 43, and covered the literature up to early 1971. This supplement includes additional rates which have been published through July 1973.
Numerical Solution of the Equation of Electron Transport in Matter
Golovin, A I
2002-01-01
One introduces a numerical approach to solve equation of fast electron transport in a matter in plane and spherical geometry with regard to fluctuations of energy losses and generation of secondary electrons. Calculation results are shown to be in line with the experimental data. One compared the introduced approach with the method of moments
Zhao, Jing; Wang, Mei; Fu, Aiyun; Yang, Hongfang; Bu, Yuxiang
2015-08-03
We present an ab initio molecular dynamics (AIMD) simulation study into the transfer dynamics of an excess electron from its cavity-shaped hydrated electron state to a hydrated nucleobase (NB)-bound state. In contrast to the traditional view that electron localization at NBs (G/A/C/T), which is the first step for electron-induced DNA damage, is related only to dry or prehydrated electrons, and a fully hydrated electron no longer transfers to NBs, our AIMD simulations indicate that a fully hydrated electron can still transfer to NBs. We monitored the transfer dynamics of fully hydrated electrons towards hydrated NBs in aqueous solutions by using AIMD simulations and found that due to solution-structure fluctuation and attraction of NBs, a fully hydrated electron can transfer to a NB gradually over time. Concurrently, the hydrated electron cavity gradually reorganizes, distorts, and even breaks. The transfer could be completed in about 120-200 fs in four aqueous NB solutions, depending on the electron-binding ability of hydrated NBs and the structural fluctuation of the solution. The transferring electron resides in the π*-type lowest unoccupied molecular orbital of the NB, which leads to a hydrated NB anion. Clearly, the observed transfer of hydrated electrons can be attributed to the strong electron-binding ability of hydrated NBs over the hydrated electron cavity, which is the driving force, and the transfer dynamics is structure-fluctuation controlled. This work provides new insights into the evolution dynamics of hydrated electrons and provides some helpful information for understanding the DNA-damage mechanism in solution. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Energy Technology Data Exchange (ETDEWEB)
Chemerisov, Sergey [Argonne National Lab. (ANL), Argonne, IL (United States); Gromov, Roman [Argonne National Lab. (ANL), Argonne, IL (United States); Makarashvili, Vakho [Argonne National Lab. (ANL), Argonne, IL (United States); Heltemes, Thad [Argonne National Lab. (ANL), Argonne, IL (United States); Sun, Zaijing [Argonne National Lab. (ANL), Argonne, IL (United States); Wardle, Kent E. [Argonne National Lab. (ANL), Argonne, IL (United States); Bailey, James [Argonne National Lab. (ANL), Argonne, IL (United States); Quigley, Kevin [Argonne National Lab. (ANL), Argonne, IL (United States); Stepinski, Dominique [Argonne National Lab. (ANL), Argonne, IL (United States); Vandegrift, George [Argonne National Lab. (ANL), Argonne, IL (United States)
2014-10-01
Argonne is assisting SHINE Medical Technologies in developing SHINE, a system for producing fission-product ^{99}Mo using a D/T-accelerator to produce fission in a non-critical target solution of aqueous uranyl sulfate. We have developed an experimental setup for studying thermal-hydraulics and bubble formation in the uranyl sulfate solution to simulate conditions expected in the SHINE target solution during irradiation. A direct electron beam from the linac accelerator will be used to irradiate a 20 L solution (sector of the solution vessel). Because the solution will undergo radiolytic decomposition, we will be able to study bubble formation and dynamics and effects of convection and temperature on bubble behavior. These experiments will serve as a verification/ validation tool for the thermal-hydraulic model. Utilization of the direct electron beam for irradiation allows homogeneous heating of a large solution volume and simplifies observation of the bubble dynamics simultaneously with thermal-hydraulic data collection, which will complement data collected during operation of the miniSHINE experiment. Irradiation will be conducted using a 30-40 MeV electron beam from the high-power linac accelerator. The total electron-beam power will be 20 kW, which will yield a power density on the order of 1 kW/L. The solution volume will be cooled on the front and back surfaces and central tube to mimic the geometry of the proposed SHINE solution vessel. Also, multiple thermocouples will be inserted into the solution vessel to map thermal profiles. The experimental design is now complete, and installation and testing are in progress.
Some Standard model problems and possible solutions
Barranco, J.
2016-10-01
Three problems of the standard model of elementary particles are studied from a phenomenological approach. (i) It is shown that the Dirac or the Majorana nature of the neutrino can be studied by looking for differences in the v-electron scattering if the polarization of the neutrino is considered. (ii) The absolute scale of the neutrino mass can be set if a four zero mass matrix texture is considered for the leptons. It is found that m ν3 ∼⃒ 0.05 eV. (iii) It is shown that it is possible -within a certain class of two Higgs model extensions of the standard model- to have a cancelation of the quadratic divergences to the mass of physical Higgs boson.
Institute of Scientific and Technical Information of China (English)
湛昌国
2011-01-01
This is a brief review of some recent progress in the development and application of firstprinciples electronic structure approaches for molecules in solution.In particular,it accounts for the background,theoretical features,and representative applications of a recently developed,truly accurate continuum solvation model which is known as Surface and Volume Polarization for Electrostatics(SVPE)or Fully Polarizable Continuum Model(FPCM)in literature.The FPCM-based first-principles electronic structure approaches have been widely employed to study a variety of chemical and biochemical problems and serve as an integrated part of various computational protocols for rational drug design.Some perspective of the future of the FPCM-based first-principles electronic structure approaches is also given.
Rotational nuclear models and electron scattering
Energy Technology Data Exchange (ETDEWEB)
Moya de Guerra, E.
1986-05-01
A review is made of the basic formalism involved in the application of nuclear rotational models to the problem of electron scattering from axially symmetric deformed nuclei. Emphasis is made on the use of electron scattering to extract information on the nature of the collective rotational model. In this respect, the interest of using polarized beam and target is discussed with the help of illustrative examples. Concerning the nuclear structure four rotational models are considered: Two microscopic models, namely the Projected Hartree-Fock (PHF) and cranking models; and two collective models, the rigid rotor and the irrotational flow models. The problem of current conservation within the different models is also discussed.
Majorana solutions to the two-electron problem
Esposito, S
2012-01-01
A review of the known different methods and results devised to study the two-electron atom problem, appeared in the early years of quantum mechanics, is given, with particular reference to the calculations of the ground state energy of helium. This is supplemented by several, unpublished results obtained around the same years by Ettore Majorana, which results did not convey in his published papers on the argument, and thus remained unknown until now. Particularly interesting, even for current research in atomic and nuclear physics, is a general variant of the variational method, developed by Majorana in order to take directly into account, already in the trial wavefunction, the action of the full Hamiltonian operator of a given quantum system. Moreover, notable calculations specialized to the study of the two-electron problem show the introduction of the remarkable concept of an effective nuclear charge different for the two electrons (thus generalizing previous known results), and an application of the pertu...
Winter, Bernd
2009-03-01
X-ray photoelectron spectroscopy measurements from a vacuum liquid microjet are performed to investigate the electronic structure of aqueous solutions. Here, focus is on the excited-state dynamics of chloride and hydroxide anions in water, following core-level excitation. A series of Cl^-(aq) charge-transfer-to-solvent (CTTS) states, and their ultrafast relaxation, on the time scale of the core hole, is identified from the occurrence of spectator Auger decay. Resonant oxygen 1s excitation of aqueous hydroxide, in contrast, leads to non-local decay, involving energy transfer into a neighboring water molecule. This channel is argued to arise from the weak hydrogen donor bond of OH^-(aq), and thus identifies a special transient hydration configuration, which can explain hydroxide's unusual and fast transport in water. Analogous measurements from pure water point to a similar relaxation channel, which is concluded from a strong isotope effect. The characteristic resonance spectral features are considerably stronger for H2O(aq) than for D2O(aq). As for OH^-(aq) the results can be understood in terms of energy transfer from the excited water molecule to a neighbor water molecule.
Solution profiles for some simple combustion models
Energy Technology Data Exchange (ETDEWEB)
Bebernes, J.; Eberly, D.; Fulks, W.
1986-01-01
In this paper, the shape (solution profile) of the solutions of the Gelfand problem and the perturbed Gelfand problem are studied. Both of these models play a fundamental role in the mathematical theory of thermal explosions for finite rigid and gaseous systems. For rigid systems the physical processes are determined by a pointwise balance between chemical heat addition and heat loss by conduction. During the inductive period, with a duration measured by the conduction time scale of the bounding container, the heat released by the chemical reaction is redistributed by thermal conduction. As the temperature of the container increases, the reaction rate grows dramatically. Eventually, the characteristic time for heat release becomes significantly smaller than the conduction time in a well-defined hot spot embedded in the system. Then the heat released is used almost entirely to increase the hot-spot temperature. The purpose of this paper is to show that both models detect this hot-spot development in a very precise manner. This hot-spot development had previously been detected only numerically.
Kong, Chao; Hai, Kuo; Tan, Jintao; Chen, Hao; Hai, Wenhua
2016-03-01
Nonlinear Kronig-Penney model has been frequently employed to study transmission problem of electron wave in a doped semiconductor superlattice or in a nonlinear electrified chain. Here from an integral equation we derive a novel exact solution of the problem, which contains a simple nonlinear map connecting transmission coefficient with system parameters. Consequently, we propose a scheme to manipulate electronic distribution and transmission by adjusting the system parameters. A new quantum coherence effect is evidenced by the strict expression of transmission coefficient, which results in the aperiodic electronic distributions and different transmission coefficients including the approximate zero transmission and total transmission, and the multiple transmissions. The method based on the concise exact solution can be applied directly to some nonlinear cold atomic systems and a lot of linear Kronig-Penney systems, and also can be extended to investigate electronic transport in different discrete nonlinear systems.
Solution-processable organic dielectrics for graphene electronics
Mattevi, Cecilia; Colléaux, Florian; Kim, HoKwon; Lin, Yen-Hung; Park, Kyung T.; Chhowalla, Manish; Anthopoulos, Thomas D.
2012-08-01
We report the fabrication, at low-temperature, of solution processed graphene transistors based on carefully engineered graphene/organic dielectric interfaces. Graphene transistors based on these interfaces show improved performance and reliability when compared with traditional SiO2 based devices. The dielectric materials investigated include Hyflon AD (Solvay), a low-k fluoropolymer, and various organic self-assembled monolayer (SAM) nanodielectrics. Both types of dielectric are solution processed and yield graphene transistors with similar operating characteristics, namely high charge carrier mobility, hysteresis free operation, negligible doping effect and improved operating stability as compared to bare SiO2 based devices. Importantly, the use of SAM nanodielectrics enables the demonstration of low operating voltage ( < |1.5| V), solution-processable and flexible graphene transistors with tunable doping characteristics through molecular engineering of the SAM’s molecular length and terminal group. The work is a significant step towards graphene microelectronics where large-volume and low-temperature processing are required.
Electronic Education System Model-2
Güllü, Fatih; Kuusik, Rein; Laanpere, Mart
2015-01-01
In this study we presented new EES Model-2 extended from EES model for more productive implementation in e-learning process design and modelling in higher education. The most updates were related to uppermost instructional layer. We updated learning processes object of the layer for adaptation of educational process for young and old people,…
THE ROLE OF ELECTRON CONFIGURATION ON PROPERTIES IN DILUTE SOLID SOLUTION ALLOYS
THE ROLE OF ELECTRON CONFIGURATION ON THE PROPERTIES OF DILUTE SOLID SOLUTION ALLOYS IS DISCUSSED IN TERMS OF THE EFFECT OF DILUTE IMPURITIES ON THE RECRYSTALLIZATION CHARACTERISTICS OF PURE METALLIC ELEMENTS.
Analytic solution of simplified Cardan's shaft model
Directory of Open Access Journals (Sweden)
Zajíček M.
2014-12-01
Full Text Available Torsional oscillations and stability assessment of the homokinetic Cardan shaft with a small misalignment angle is described in this paper. The simplified mathematical model of this system leads to the linearized equation of the Mathieu's type. This equation with and without a stationary damping parameter is considered. The solution of the original differential equation is identical with those one of the Fredholm’s integral equation with degenerated kernel assembled by means of a periodic Green's function. The conditions of solvability of such problem enable the identification of the borders between stability and instability regions. These results are presented in the form of stability charts and they are verified using the Floquet theory. The correctness of oscillation results for the system with periodic stiffness is then validated by means of the Runge-Kutta integration method.
Electron attachment to DNA single strands: gas phase and aqueous solution
Gu, Jiande; Xie, Yaoming; Schaefer, Henry F.
2007-01-01
The 2′-deoxyguanosine-3′,5′-diphosphate, 2′-deoxyadenosine-3′,5′-diphosphate, 2′-deoxycytidine-3′,5′-diphosphate and 2′-deoxythymidine-3′,5′-diphosphate systems are the smallest units of a DNA single strand. Exploring these comprehensive subunits with reliable density functional methods enables one to approach reasonable predictions of the properties of DNA single strands. With these models, DNA single strands are found to have a strong tendency to capture low-energy electrons. The vertical attachment energies (VEAs) predicted for 3′,5′-dTDP (0.17 eV) and 3′,5′-dGDP (0.14 eV) indicate that both the thymine-rich and the guanine-rich DNA single strands have the ability to capture electrons. The adiabatic electron affinities (AEAs) of the nucleotides considered here range from 0.22 to 0.52 eV and follow the order 3′,5′-dTDP > 3′,5′-dCDP > 3′,5′-dGDP > 3′,5′-dADP. A substantial increase in the AEA is observed compared to that of the corresponding nucleic acid bases and the corresponding nucleosides. Furthermore, aqueous solution simulations dramatically increase the electron attracting properties of the DNA single strands. The present investigation illustrates that in the gas phase, the excess electron is situated both on the nucleobase and on the phosphate moiety for DNA single strands. However, the distribution of the extra negative charge is uneven. The attached electron favors the base moiety for the pyrimidine, while it prefers the 3′-phosphate subunit for the purine DNA single strands. In contrast, the attached electron is tightly bound to the base fragment for the cytidine, thymidine and adenosine nucleotides, while it almost exclusively resides in the vicinity of the 3′-phosphate group for the guanosine nucleotides due to the solvent effects. The comparatively low vertical detachment energies (VDEs) predicted for 3′,5′-dADP− (0.26 eV) and 3′,5′-dGDP− (0.32 eV) indicate that electron detachment
Electronic noise modeling in statistical iterative reconstruction.
Xu, Jingyan; Tsui, Benjamin M W
2009-06-01
We consider electronic noise modeling in tomographic image reconstruction when the measured signal is the sum of a Gaussian distributed electronic noise component and another random variable whose log-likelihood function satisfies a certain linearity condition. Examples of such likelihood functions include the Poisson distribution and an exponential dispersion (ED) model that can approximate the signal statistics in integration mode X-ray detectors. We formulate the image reconstruction problem as a maximum-likelihood estimation problem. Using an expectation-maximization approach, we demonstrate that a reconstruction algorithm can be obtained following a simple substitution rule from the one previously derived without electronic noise considerations. To illustrate the applicability of the substitution rule, we present examples of a fully iterative reconstruction algorithm and a sinogram smoothing algorithm both in transmission CT reconstruction when the measured signal contains additive electronic noise. Our simulation studies show the potential usefulness of accurate electronic noise modeling in low-dose CT applications.
STEADY-STATE MODEL OF SOLAR WIND ELECTRONS REVISITED
Energy Technology Data Exchange (ETDEWEB)
Yoon, Peter H.; Kim, Sunjung; Choe, G. S., E-mail: yoonp@umd.edu [School of Space Research, Kyung Hee University, Yongin, Gyeonggi 446-701 (Korea, Republic of)
2015-10-20
In a recent paper, Kim et al. put forth a steady-state model for the solar wind electrons. The model assumed local equilibrium between the halo electrons, characterized by an intermediate energy range, and the whistler-range fluctuations. The basic wave–particle interaction is assumed to be the cyclotron resonance. Similarly, it was assumed that a dynamical steady state is established between the highly energetic superhalo electrons and high-frequency Langmuir fluctuations. Comparisons with the measured solar wind electron velocity distribution function (VDF) during quiet times were also made, and reasonable agreements were obtained. In such a model, however, only the steady-state solution for the Fokker–Planck type of electron particle kinetic equation was considered. The present paper complements the previous analysis by considering both the steady-state particle and wave kinetic equations. It is shown that the model halo and superhalo electron VDFs, as well as the assumed wave intensity spectra for the whistler and Langmuir fluctuations, approximately satisfy the quasi-linear wave kinetic equations in an approximate sense, thus further validating the local equilibrium model constructed in the paper by Kim et al.
Status of Galileo interim radiation electron model
Garrett, H. B.; Jun, I.; Ratliff, J. M.; Evans, R. W.; Clough, G. A.; McEntire, R. W.
2003-01-01
Measurements of the high energy, omni-directional electron environment by the Galileo spacecraft Energetic Particle Detector (EDP) were used to develop a new model of Jupiter's trapped electron radiation in the jovian equatorial plane for the range 8 to 16 Jupiter radii.
Reconfiguration of Analog Electronics for Extreme Environments: Problem or Solution?
Stoica, Adrian; Zebulum, Ricardo; Keymeulen, Didier; Guo, Xin
2005-01-01
This paper argues in favor of adaptive reconfiguration as a technique to expand the operational envelope of analog electronics for extreme environments (EE). In addition to hardening-by-process and hardening-by-design, "hardening-by-reconfiguration", when applicable, could be used to mitigate drifts, degradation, or damage on electronic devices (chips) in EE, by using re-configurable devices and an adaptive self-reconfiguration of their circuit topology. Conventional circuit design exploits device characteristics within a certain temperature/radiation range; when that is exceeded, the circuit function degrades. On a reconfigurable device, although component parameters change in EE, as long as devices still operate, albeit degraded, a new circuit design, suitable for new parameter values, may be mapped into the reconfigurable structure to recover the initial circuit function. Partly degraded resources are still used, while completely damaged resources are bypassed. Designs suitable for various environmental conditions can be determined prior to operation or can be determined in-situ, by adaptive reconfiguration algorithms running on built-in digital controllers. Laboratory demonstrations of this technique were performed by JPL in several independent experiments in which bulk CMOS reconfigurable devices were exposed to, and degraded by, low temperatures (approx. 196 C), high temperatures (approx.300 C) or radiation (300kRad TID), and then recovered by adaptive reconfiguration using evolutionary search algorithms. Taking this technology from Technology Readiness Level (TRL) 3 to TRL 5 is the target of a current NASA project.
Solution of a multiple-scattering inverse problem: electron diffraction from surfaces.
Saldin, D K; Seubert, A; Heinz, K
2002-03-18
We present a solution to the multiple-scattering inverse problem for low-energy electron diffraction that enables the determination of the three-dimensional atomic structure of an entire surface unit cell directly from measured data. The solution requires a knowledge of the structure of the underlying bulk crystal and is implemented by a maximum entropy algorithm.
Modeling microwave/electron-cloud interaction
Mattes, M; Zimmermann, F
2013-01-01
Starting from the separate codes BI-RME and ECLOUD or PyECLOUD, we are developing a novel joint simulation tool, which models the combined effect of a charged particle beam and of microwaves on an electron cloud. Possible applications include the degradation of microwave transmission in tele-communication satellites by electron clouds; the microwave-transmission tecchniques being used in particle accelerators for the purpose of electroncloud diagnostics; the microwave emission by the electron cloud itself in the presence of a magnetic field; and the possible suppression of electron-cloud formation in an accelerator by injecting microwaves of suitable amplitude and frequency. A few early simulation results are presented.
Power electronics solution to dust emissions from thermal power plants
Directory of Open Access Journals (Sweden)
Vukosavić Slobodan
2010-01-01
Full Text Available Thermal power stations emit significant amounts of fly ash and ultra fine particles into the atmosphere. Electrostatic precipitators (ESP or electro filters remove flying ashes and fine particles from the flue gas before passing the gas into the chimney. Maximum allowable value of dust is 50 mg/m3 and it requires that the efficiency of the ESPs better than 99 %, which calls for an increase of active surface of the electrodes, hence increasing the filter volume and the weight of steel used for the filter. In previous decades, electrostatic precipitators in thermal power plants were fed by thyristor controlled, single phase fed devices having a high degree of reliability, but with a relatively low collection efficiency, hence requiring large effective surface of the collection plates and a large weight of steel construction in order to achieve the prescribed emission limits. Collection efficiency and energy efficiency of the electrostatic precipitator can be increased by applying high frequency high voltage power supply (HF HV. Electrical engineering faculty of the University of Belgrade (ETF has developed technology and HF HV equipment for the ESP power supply. This solution was subjected to extensive experimental investigation at TE Morava from 2008 to 2010. High frequency power supply is proven to reduce emission two times in controlled conditions while increasing energy efficiency of the precipitator, compared to the conventional thyristor controlled 50Hz supply. Two high frequency high voltage unit AR70/1000 with parameters 70 kV and 1000 mA are installed at TE Morava and thoroughly testes. It was found that the HF HV power supply of the ESP at TE Morava increases collection efficiency so that emission of fine particles and flying ashes are halved, brought down to only 50 % of the emissions encountered with conventional 50 Hz thyristor driven power supplies. On the basis of this study, conclusion is drawn that the equipment comprising HF HV
Electronic Corpora as Translation Tools: A Solution in Practice
Directory of Open Access Journals (Sweden)
Vigdis Jensen
2012-08-01
Full Text Available Small bilingual text corpora from a source and target language can be important sources of specialized language tracking for translators. A corpus platform can supplement or replace traditional reference works such as dictionaries and encyclopedia, which are rarely sufficient for the professional translator who has to get a cross-linguistic overview of a new area or a new line of business. Relevant internet texts can be compiled ‘on the fly’, but internet data needs to be sorted and analyzed for rational use. Today, such sorting and analysis can be made by a low-tech, analytical software tool. This article demonstrates how strategic steps of compiling and retrieving linguistic data by means of specific search strategies can be used to make electronic corpora an efficient tool in translators’ daily work with fields that involve new terminology, but where the skills requested to work correspond to being able to perform an advanced Google search. We show the different steps in setting up and working with an ad-hoc corpus, illustrated by means of the software AntConc applied on the SEO area.
Multidisciplinary Modelling Tools for Power Electronic Circuits
DEFF Research Database (Denmark)
Bahman, Amir Sajjad
This thesis presents multidisciplinary modelling techniques in a Design For Reliability (DFR) approach for power electronic circuits. With increasing penetration of renewable energy systems, the demand for reliable power conversion systems is becoming critical. Since a large part of electricity...... in reliability assessment of power modules, a three-dimensional lumped thermal network is proposed to be used for fast, accurate and detailed temperature estimation of power module in dynamic operation and different boundary conditions. Since an important issue in the reliability of power electronics...... are generic and valid to be used in circuit simulators or any programing software. These models are important building blocks for the reliable design process or performance assessment of power electronic circuits. The models can save time and cost in power electronics packaging and power converter to evaluate...
Exact Solutions in Modified Gravity Models
Directory of Open Access Journals (Sweden)
Valery V. Obukhov
2012-06-01
Full Text Available We review the exact solutions in modified gravity. It is one of the main problems of mathematical physics for the gravity theory. One can obtain an exact solution if the field equations reduce to a system of ordinary differential equations. In this paper we consider a number of exact solutions obtained by the method of separation of variables. Some applications to Cosmology and BH entropy are briefly mentioned.
Exact Solutions in Modified Gravity Models
Makarenko, Andrey N
2012-01-01
We review the exact solutions in modified gravity. It is one of the main problems of mathematical physics for the gravity theory. One can obtain an exact solution if the field equations reduce to a system of ordinary differential equations. In this paper we consider a number of exact solutions obtained by the method of separation of variables. Some applications to Cosmology and BH entropy are briefly mentioned.
Towards Novel Energy Solutions - an Electronic/Atomistic Simulation Approach
Dong, Rui
This thesis focuses on computer modeling and multi-scale simulations of new materials that can potentially be used in novel energy applications, i.e., the dye molecules in dye-sensitizedsolar- cells and polymers for the capacitive energy storage. The aim is to understand physical properties of existing materials and then to find ways to improve them. (Abstract shortened by ProQuest.).
Kulasiri, Don
2002-01-01
Most of the natural and biological phenomena such as solute transport in porous media exhibit variability which can not be modeled by using deterministic approaches. There is evidence in natural phenomena to suggest that some of the observations can not be explained by using the models which give deterministic solutions. Stochastic processes have a rich repository of objects which can be used to express the randomness inherent in the system and the evolution of the system over time. The attractiveness of the stochastic differential equations (SDE) and stochastic partial differential equations (SPDE) come from the fact that we can integrate the variability of the system along with the scientific knowledge pertaining to the system. One of the aims of this book is to explaim some useufl concepts in stochastic dynamics so that the scientists and engineers with a background in undergraduate differential calculus could appreciate the applicability and appropriateness of these developments in mathematics. The ideas ...
Closed circuit recovery of copper, lead and iron from electronic waste with citrate solutions.
Torres, Robinson; Lapidus, Gretchen T
2017-02-01
An integral closed circuit hydrometallurgical process is presented for base metal recovery from electronic waste. The leaching medium consists of a sodium citrate solution, from which base metals are retrieved by direct electrowinning, and the barren solution is recycled back to the leaching stage. This leaching-electrowinning cycle was repeated four times. The redox properties of the fresh citrate solution, as well as the leach liquors, were characterized by cyclic voltammetry to determine adequate conditions for metal reduction, as well as to limit citrate degradation. The leaching efficiency of electronic waste, employing the same solution after four complete cycles was 71, 83 and 94% for copper, iron and lead, respectively, compared to the original leach with fresh citrate solution.
Analysis of Valence Electron Structure of RE in Solid Solution in Medium and Low Carbon Steel
Institute of Scientific and Technical Information of China (English)
朱莹光; 刘艳; 刘志林; 刘伟东
2004-01-01
According to EET theory,the valence electron structures of RE in the solid solution of austenite,pearlite and martensite were calculated.The influence of RE in solid solution on phase transformation of pearlite and recrystallization of martensite was explained by the valence electron structure data of phases.Calculating results indicate that C element is favorite to enhance the number of RE in the solid solution.RE in the solute solution shortens the incubation period of proeutectoid ferrite,increases its quantity and carbon content,decreases the quantity of pearlite and thickness of its lamellas and lamellar spacing,then the strength and hardness of pearlite are improved and granular pearlite can be obtained.RE dissolved in martensite intensifies martensite,enhances tempering stability of martensite,increases its recrystallization temperature and prolongs the holding time needed during tempering.
Solutions to a nonlinear drift-diffusion model for semiconductors
Directory of Open Access Journals (Sweden)
Weifu Fang
1999-05-01
Full Text Available A nonlinear drift-diffusion model for semiconductors is analyzed to show the existence of non-vacuum global solutions and stationary solutions. The long time behavior of the solutions is studied by establishing the existence of an absorbing set and a compact attractor of the dynamical system. Parallel results on vacuum solutions are also obtained under weaker conditions on model parameters.
Optimisation-Based Solution Methods for Set Partitioning Models
DEFF Research Database (Denmark)
Rasmussen, Matias Sevel
The scheduling of crew, i.e. the construction of work schedules for crew members, is often not a trivial task, but a complex puzzle. The task is complicated by rules, restrictions, and preferences. Therefore, manual solutions as well as solutions from standard software packages are not always su......_cient with respect to solution quality and solution time. Enhancement of the overall solution quality as well as the solution time can be of vital importance to many organisations. The _elds of operations research and mathematical optimisation deal with mathematical modelling of di_cult scheduling problems (among...... other topics). The _elds also deal with the development of sophisticated solution methods for these mathematical models. This thesis describes the set partitioning model which has been widely used for modelling crew scheduling problems. Integer properties for the set partitioning model are shown...
A family of exact solutions for unpolarized Gowdy models
Obregón, O; Obregon, Octavio; Ryan, Michael P.
1998-01-01
Unpolarized Gowdy models are inhomogeneous cosmological models that depend on time and one spatial variable and have complicated nonlinear equations of motion. There are two topologies associated with these models, a three-torus and a one-sphere cross a two-sphere. The three-torus models have been used for numerical studies because it seems difficult to find analytic solutions to their nonlinear Einstein equations. The one-sphere cross tow-sphere models have even more complicated equations, but at least one family of analytic solutions can be given as a reinterpretation of known solutions. Various properties of this family of solutions are studied.
Teaching Chemistry with Electron Density Models
Shusterman, Gwendolyn P.; Shusterman, Alan J.
1997-07-01
Linus Pauling once said that a topic must satisfy two criteria before it can be taught to students. First, students must be able to assimilate the topic within a reasonable amount of time. Second, the topic must be relevant to the educational needs and interests of the students. Unfortunately, the standard general chemistry textbook presentation of "electronic structure theory", set as it is in the language of molecular orbitals, has a difficult time satisfying either criterion. Many of the quantum mechanical aspects of molecular orbitals are too difficult for most beginning students to appreciate, much less master, and the few applications that are presented in the typical textbook are too limited in scope to excite much student interest. This article describes a powerful new method for teaching students about electronic structure and its relevance to chemical phenomena. This method, which we have developed and used for several years in general chemistry (G.P.S.) and organic chemistry (A.J.S.) courses, relies on computer-generated three-dimensional models of electron density distributions, and largely satisfies Pauling's two criteria. Students find electron density models easy to understand and use, and because these models are easily applied to a broad range of topics, they successfully convey to students the importance of electronic structure. In addition, when students finally learn about orbital concepts they are better prepared because they already have a well-developed three-dimensional picture of electronic structure to fall back on. We note in this regard that the types of models we use have found widespread, rigorous application in chemical research (1, 2), so students who understand and use electron density models do not need to "unlearn" anything before progressing to more advanced theories.
Modeling Solute Reactivity in a Phreatic Solution Conduit Penetrating a Karst Aquifer
Field, M.
2014-12-01
A two-dimensional model for solute migration, transformation, and sorption in a phreatic solution conduit penetrating a karst aquifer is presented in which the solute is anthropogenic to the natural system. Transformation of a reacting solute in a solution conduit has generally been accepted as likely occurring but actual physical measurements and mathematical analyses of the suspected process are lacking, primarily because of the logistics of sample collection and the complexities associated with solute transport through solution conduits. The model demonstrates how a reacting solute might be converted to a product solute some of which then diffuses to the solution conduit wall where it may become adsorbed. Model effects vary for laminar flow and turbulent flow in the axial direction. Laminar and turbulent diffusion in the radial direction also exhibits marked differences. In addition to single reaction zones simulations considered multiple adjacent and nonadjacent reaction zones, both with varying reaction rates. Reaction zones were found to enhance subsequent reactions due to some overlap resulting from the hydrodynamic dispersion caused by the axial flow. The simulations showed that varying the reaction rate coefficient strongly affects solute reactions, but that varying deposition coefficients had only minimal impacts. Application of the model to a tracer test that used the tracer dye, Rhodamine WT which readily converts to deaminoalkylated Rhodamine WT after release, illustrates how the model may be used to suggest a possible cause for less than 100% tracer mass recovery. In terms of pollutants in a karst aquifer the model suggests a possible explanation for pollutant transformation in a solution conduit.
Periodic solutions of nonautonomous differential systems modeling obesity population
Energy Technology Data Exchange (ETDEWEB)
Arenas, Abraham J. [Departamento de Matematicas y Estadistica, Universidad de Cordoba Monteria (Colombia)], E-mail: aarenas@sinu.unicordoba.edu.co; Gonzalez-Parra, Gilberto [Departamento de Calculo, Universidad de los Andes, Merida (Venezuela, Bolivarian Republic of)], E-mail: gcarlos@ula.ve; Jodar, Lucas [Instituto de Matematica Multidisciplinar, Universidad Politecnica de Valencia Edificio 8G, 2o, 46022 Valencia (Spain)], E-mail: ljodar@imm.upv.es
2009-10-30
In this paper we study the periodic behaviour of the solutions of a nonautonomous model for obesity population. The mathematical model represented by a nonautonomous system of nonlinear ordinary differential equations is used to model the dynamics of obese populations. Numerical simulations suggest periodic behaviour of subpopulations solutions. Sufficient conditions which guarantee the existence of a periodic positive solution are obtained using a continuation theorem based on coincidence degree theory.
Energy Technology Data Exchange (ETDEWEB)
Salminen, Kalle; Kuosmanen, Päivi; Pusa, Matti [Aalto University, Department of Chemistry, Laboratory of Analytical Chemistry, P.O. Box 16100, FI-00076 Aalto (Finland); Kulmala, Oskari [University of Helsinki, Department of Physics, P.O. Box 64, FI-00014 (Finland); Håkansson, Markus [Aalto University, Department of Chemistry, Laboratory of Analytical Chemistry, P.O. Box 16100, FI-00076 Aalto (Finland); Kulmala, Sakari, E-mail: sakari.kulmala@aalto.fi [Aalto University, Department of Chemistry, Laboratory of Analytical Chemistry, P.O. Box 16100, FI-00076 Aalto (Finland)
2016-03-17
Hole injection into aqueous electrolyte solution is proposed to occur when oxide-coated aluminum electrode is anodically pulse-polarized by a voltage pulse train containing sufficiently high-voltage anodic pulses. The effects of anodic pulses are studied by using an aromatic Tb(III) chelate as a probe known to produce intensive hot electron-induced electrochemiluminescence (HECL) with plain cathodic pulses and preoxidized electrodes. The presently studied system allows injection of hot electrons and holes successively into aqueous electrolyte solutions and can be utilized in detecting electrochemiluminescent labels in fully aqueous solutions, and actually, the system is suggested to be quite close to a pulse radiolysis system providing hydrated electrons and hydroxyl radicals as the primary radicals in aqueous solution without the problems and hazards of ionizing radiation. The analytical power of the present excitation waveforms are that they allow detection of electrochemiluminescent labels at very low detection limits in bioaffinity assays such as in immunoassays or DNA probe assays. The two important properties of the present waveforms are: (i) they provide in situ oxidation of the electrode surface resulting in the desired oxide film thickness and (ii) they can provide one-electron oxidants for the system by hole injection either via F- and F{sup +}-center band of the oxide or by direct hole injection to valence band of water at highly anodic pulse amplitudes. - Highlights: • Hot electrons injected into aqueous electrolyte solution. • Generation of hydrated electrons. • Hole injection into aqueous electrolyte solution. • Generation of hydroxyl radicals.
An Algebraic Solution for the Kermack-McKendrick Model
Carvalho, Alexsandro M
2016-01-01
We present an algebraic solution for the Susceptible-Infective-Removed (SIR) model originally presented by Kermack-McKendrick in 1927. Starting from the differential equation for the removed subjects presented by them in the original paper, we re-write it in a slightly different form in order to derive formally the solution, unless one integration. Then, using algebraic techniques and some well justified numerical assumptions we obtain an analytic solution for the integral. Finally, we compare the numerical solution of the differential equations of the SIR model with the analytically solution here proposed, showing an excellent agreement.
Itinerant electron model and conductance of DNA
Institute of Scientific and Technical Information of China (English)
Zhen QU; Da-wei KANG; Xu-tuan GAO; Shi-jie XIE
2008-01-01
DNA (Deoxyribonucleic acid) has recently caught the attention of chemists and physicists.A major reason for this interest is DNA's potential use in nanoelectronie devices,both as a template for assembling nanocireuits and as an element of such circuits.However,the electronic properties of the DNA molecule remain very controversial. Charge-transfer reactions and conductivity measurements show a large variety of possible electronic behavior,ranging from Anderson and bandgap insulators to effective molecular wires and induced superconductors.In this review article,we summarize the wide-ranging experimental and theoretical results of charge transport in DNA.An itinerant electron model is suggested and the effect of the density of itinerant electrons on the conductivity of DNA is studied.Calculations show that a DNA molecule may show conductivity from insulating to metallic,which explains the controversial and profuse electric characteristics of DNA to some extent.
Solutions of two-factor models with variable interest rates
Li, Jinglu; Clemons, C. B.; Young, G. W.; Zhu, J.
2008-12-01
The focus of this work is on numerical solutions to two-factor option pricing partial differential equations with variable interest rates. Two interest rate models, the Vasicek model and the Cox-Ingersoll-Ross model (CIR), are considered. Emphasis is placed on the definition and implementation of boundary conditions for different portfolio models, and on appropriate truncation of the computational domain. An exact solution to the Vasicek model and an exact solution for the price of bonds convertible to stock at expiration under a stochastic interest rate are derived. The exact solutions are used to evaluate the accuracy of the numerical simulation schemes. For the numerical simulations the pricing solution is analyzed as the market completeness decreases from the ideal complete level to one with higher volatility of the interest rate and a slower mean-reverting environment. Simulations indicate that the CIR model yields more reasonable results than the Vasicek model in a less complete market.
Radiation Belt Electron Dynamics: Modeling Atmospheric Losses
Selesnick, R. S.
2003-01-01
The first year of work on this project has been completed. This report provides a summary of the progress made and the plan for the coming year. Also included with this report is a preprint of an article that was accepted for publication in Journal of Geophysical Research and describes in detail most of the results from the first year of effort. The goal for the first year was to develop a radiation belt electron model for fitting to data from the SAMPEX and Polar satellites that would provide an empirical description of the electron losses into the upper atmosphere. This was largely accomplished according to the original plan (with one exception being that, for reasons described below, the inclusion of the loss cone electrons in the model was deferred). The main concerns at the start were to accurately represent the balance between pitch angle diffusion and eastward drift that determines the dominant features of the low altitude data, and then to accurately convert the model into simulated data based on the characteristics of the particular electron detectors. Considerable effort was devoted to achieving these ends. Once the model was providing accurate results it was applied to data sets selected from appropriate periods in 1997, 1998, and 1999. For each interval of -30 to 60 days, the model parameters were calculated daily, thus providing good short and long term temporal resolution, and for a range of radial locations from L = 2.7 to 3.9. .
Lattice Boltzmann Model for Electronic Structure Simulations
Mendoza, M; Succi, S
2015-01-01
Recently, a new connection between density functional theory and kinetic theory has been proposed. In particular, it was shown that the Kohn-Sham (KS) equations can be reformulated as a macroscopic limit of the steady-state solution of a suitable single-particle kinetic equation. By using a discrete version of this new formalism, the exchange and correlation energies of simple atoms and the geometrical configuration of the methane molecule were calculated accurately. Here, we discuss the main ideas behind the lattice kinetic approach to electronic structure computations, offer some considerations for prospective extensions, and also show additional numerical results, namely the geometrical configuration of the water molecule.
General solution of the Dirac equation for quasi-two-dimensional electrons
Energy Technology Data Exchange (ETDEWEB)
Eremko, Alexander, E-mail: eremko@bitp.kiev.ua [Bogolyubov Institute for Theoretical Physics, Metrologichna Str., 14-b, Kyiv, 03680 (Ukraine); Brizhik, Larissa, E-mail: brizhik@bitp.kiev.ua [Bogolyubov Institute for Theoretical Physics, Metrologichna Str., 14-b, Kyiv, 03680 (Ukraine); Loktev, Vadim, E-mail: vloktev@bitp.kiev.ua [Bogolyubov Institute for Theoretical Physics, Metrologichna Str., 14-b, Kyiv, 03680 (Ukraine); National Technical University of Ukraine “KPI”, Peremohy av., 37, Kyiv, 03056 (Ukraine)
2016-06-15
The general solution of the Dirac equation for quasi-two-dimensional electrons confined in an asymmetric quantum well, is found. The energy spectrum of such a system is exactly calculated using special unitary operator and is shown to depend on the electron spin polarization. This solution contains free parameters, whose variation continuously transforms one known particular solution into another. As an example, two different cases are considered in detail: electron in a deep and in a strongly asymmetric shallow quantum well. The effective mass renormalized by relativistic corrections and Bychkov–Rashba coefficients are analytically obtained for both cases. It is demonstrated that the general solution transforms to the particular solutions, found previously (Eremko et al., 2015) with the use of spin invariants. The general solution allows to establish conditions at which a specific (accompanied or non-accompanied by Rashba splitting) spin state can be realized. These results can prompt the ways to control the spin degree of freedom via the synthesis of spintronic heterostructures with the required properties.
On the miniaturisation of convenction cooling solutions applicable to portable electronic devices
Stafford, Jason
2010-01-01
peer-reviewed Dimensional restrictions in electronic equipment have resulted in miniaturisation of many existing cooling technologies. In addition, cooling solutions are required to dissipate increased thermal loads to maintain component reliability and user comfort. Fans are widely used in electronics cooling to meet such thermal demands, either in standalone for direct component cooling, or in combination with a heat sink. The thermal performance of such designs when scaled to dimensions...
Hajrahimi, Nafiseh; Dehaghani, Sayed Mehdi Hejazi; Hajrahimi, Nargess; Sarmadi, Sima
2014-01-01
Implementing information technology in the best possible way can bring many advantages such as applying electronic services and facilitating tasks. Therefore, assessment of service providing systems is a way to improve the quality and elevate these systems including e-commerce, e-government, e-banking, and e-learning. This study was aimed to evaluate the electronic services in the website of Isfahan University of Medical Sciences in order to propose solutions to improve them. Furthermore, we aim to rank the solutions based on the factors that enhance the quality of electronic services by using analytic hierarchy process (AHP) method. Non-parametric test was used to assess the quality of electronic services. The assessment of propositions was based on Aqual model and they were prioritized using AHP approach. The AHP approach was used because it directly applies experts' deductions in the model, and lead to more objective results in the analysis and prioritizing the risks. After evaluating the quality of the electronic services, a multi-criteria decision making frame-work was used to prioritize the proposed solutions. Non-parametric tests and AHP approach using Expert Choice software. The results showed that students were satisfied in most of the indicators. Only a few indicators received low satisfaction from students including, design attractiveness, the amount of explanation and details of information, honesty and responsiveness of authorities, and the role of e-services in the user's relationship with university. After interviewing with Information and Communications Technology (ICT) experts at the university, measurement criteria, and solutions to improve the quality were collected. The best solutions were selected by EC software. According to the results, the solution "controlling and improving the process in handling users complaints" is of the utmost importance and authorities have to have it on the website and place great importance on updating this process
Eigenvalue solution to the electron-collisional effect on ion-acoustic and entropy waves
Institute of Scientific and Technical Information of China (English)
ZHENG; Jian
2001-01-01
［1］Braginskii,S.I.,Transport processes in a plasma,in Reviews of Plasma Physics,Vol.1,New York:Consultants Bureau,1965,205-311.［2］Ono,M.,Kulsrud,R.M.,Frequency and damping of ion acoustic waves,Phys.Fluids,1975,18(10):1287-1293.［3］Randall,C.J.,Effect of ion collisionality on ion-acoustic waves,Phys.Fluids,1982,25(12):2231-2233.［4］Tracy,M.D.,Williams,E.A.,Estabrook,K.G.et al.,Eigenvalue solution for the ion-collisional effects on ion-acoustic and entropy waves,Phys.Fluids,1993,B5(5):1430.［5］Bell,A.R.,Electron energy transport in ion waves and its relevance to laser produced plasmas,Phys.Fluids,1983,26(1):279-284.［6］Epperlein,E.M.,Short,R.W.,Simon,A.,Damping of ion-acoustic waves in the presence of electron-ion collisions,Phys.Rev.Lett.,1992,69(12):1765-1768.［7］Epperlein,E.M.,Effect of electron collisions on ion-acoustic waves and heat flow,Phys.Plasmas,1994,1(1):109-115.［8］Bychenkov,V.Y.,Myatt,J.,Rozmus,W.et al.,Quasihydrodynamic description of ion acoustic waves in a collisional plasmas,Phys.Plasmas,1994,1(8):2419-2429.［9］Bychenkov,V.Y.,Myatt,J.,Rozmus,W.et al.,Ion acoustic waves in plasmas with collisional electrons,Phys.Rev.E,1994,50(6):5134-5137.［10］Bychenkov,V.Y.,Rozmus,W.,Tikhonchuk,V.T.et al.,Nonlocal electron transport in a plasma,Phys.Rev.Lett.,1995,75(24):4405-4408.［11］Zhang,Y.Q.et al.,Density fluctuation spectra of a collision-dominated plasma measured by light scattering,Phys.Rev.Lett.,1989,62(16):1848-1851.［12］Hinton,F.L.,Collisional transport in plasma,in Handbook of Plasma Physics,Vol.1,Amsterdam:North-Holland,1983,147-199.［13］Zheng Jian,Yu Changxuan,A numerical approach to the frequencies and damping rates of ion-acoustic waves in ion-collisional plasmas,Chin.Phys.Lett.,1999,16(12):905-907.［14］Hammett,G.W.,Perkins,F.,Fluid moment models for Landau damping with application to the ion-temperature-gradient instability,Phys.Rev.Lett.,1990,64(25):3019-3022.
Stability of core–shell nanowires in selected model solutions
Energy Technology Data Exchange (ETDEWEB)
Kalska-Szostko, B., E-mail: kalska@uwb.edu.pl; Wykowska, U.; Basa, A.; Zambrzycka, E.
2015-03-30
Highlights: • Stability of the core–shell nanowires in environmental solutions were tested. • The most and the least aggressive solutions were determined. • The influence of different solutions on magnetic nanowires core was found out. - Abstract: This paper presents the studies of stability of magnetic core–shell nanowires prepared by electrochemical deposition from an acidic solution containing iron in the core and modified surface layer. The obtained nanowires were tested according to their durability in distilled water, 0.01 M citric acid, 0.9% NaCl, and commercial white wine (12% alcohol). The proposed solutions were chosen in such a way as to mimic food related environment due to a possible application of nanowires as additives to, for example, packages. After 1, 2 and 3 weeks wetting in the solutions, nanoparticles were tested by Infrared Spectroscopy, Atomic Absorption Spectroscopy, Transmission Electron Microscopy and X-ray diffraction methods.
Combinatorial model of solute transport in porous media
Institute of Scientific and Technical Information of China (English)
张妙仙; 张丽萍
2004-01-01
Modeling of solute transport is a key issue in the area of soil physics and hydrogeology. The most common approach (the convection-dispersion equation) considers an average convection flow rate and Fickian-like dispersion. Here,we propose a solute transport model in porous media of continuously expanding scale, according to the combinatorics principle. The model supposed actual porous media as a combinative body of many basic segments. First, we studied the solute transport process in each basic segment body, and then deduced the distribution of pore velocity in each basic segment body by difference approximation, finally assembled the solute transport process of each basic segment body into one of the combinative body. The simulation result coincided with the solute transport process observed in test. The model provides useful insight into the solute transport process of the non-Fickian dispersion in continuously expanding scale.
Electron Correlation Models for Optical Activity
DEFF Research Database (Denmark)
Höhn, E. G.; O. E. Weigang, Jr.
1968-01-01
A two-system no-overlap model for rotatory strength is developed for electric-dipole forbidden as well as allowed transitions. General equations which allow for full utilization of symmetry in the chromophore and in the environment are obtained. The electron correlation terms are developed in full...
Robotin, B; Ispas, A; Coman, V; Bund, A; Ilea, P
2013-11-01
This study focuses on the electrodeposition of Ni and Ni-Fe alloys from synthetic solutions similar to those obtained by the dissolution of electron gun (an electrical component of cathode ray tubes) waste. The influence of various parameters (pH, electrolyte composition, Ni(2+)/Fe(2+) ratio, current density) on the electrodeposition process was investigated. Scanning electron microscopy (SEM) and X-ray fluorescence analysis (XRFA) were used to provide information about the obtained deposits' thickness, morphology, and elemental composition. By controlling the experimental parameters, the composition of the Ni-Fe alloys can be tailored towards specific applications. Complementarily, the differences in the nucleation mechanisms for Ni, Fe and Ni-Fe deposition from sulfate solutions have been evaluated and discussed using cyclic voltammetry and potential step chronoamperometry. The obtained results suggest a progressive nucleation mechanism for Ni, while for Fe and Ni-Fe, the obtained data points are best fitted to an instantaneous nucleation model.
Trapped Electron Model 2 (TEM-2)
2010-04-25
Ginet (AFRL and MIT/Lincoln Lab). We made extensive use of the IRBEM (formerly ONERA ) library of magnetic field models and field line tracing...several others. We are aware of other efforts to develop reanalysis models of the electron radiation belts. One effort, at ONERA (Office National...sensors on GPS and geosynchronous (GEO) satellites, the ONERA group has obtained promising results, including a first physics-based data
Analytical modeling of bargaining solutions for multicast cellular services
Directory of Open Access Journals (Sweden)
Giuseppe Araniti
2013-07-01
Full Text Available Nowadays, the growing demand for group-oriented services over mobile devices has lead to the definition of new communication standards and multimedia applications in cellular systems. In this article we study the use of game theoretic solutions for these services to model and perform a trade-off analysis between fairness and efficiency in the resources allocation. More precisely, we model bargaining solutions for the multicast data services provisioning and introduce the analytical resolution for the proposed solutions.
Institute of Scientific and Technical Information of China (English)
YaoZhijian
2005-01-01
In this paper, a two-species nonautonomous competitive model with stage structure and harvesting is considered. Sufficient conditions for the existence, uniqueness, global attractivity of positive periodic solution and the existence, uniform asvmntotic stability of almost neriodic solution are obtained.
Mathematical model I. Electron and quantum mechanics
Gadre, Nitin Ramchandra
2011-03-01
The basic particle electron obeys various theories like electrodynamics, quantum mechanics and special relativity. Particle under different experimental conditions behaves differently, allowing us to observe different characteristics which become basis for these theories. In this paper, we have made an attempt to suggest a classical picture by studying the requirements of these three modern theories. The basic presumption is: There must be certain structural characteristics in a particle like electron which make it obey postulates of modern theories. As it is `difficult' to find structure of electron experimentally, we make a mathematical attempt. For a classical approach, we require well defined systems and we have studied a system with two charged particles, proton and electron in a hydrogen atom. An attempt has been made to give a model to describe electron as seen by the proton. We then discuss how the model can satisfy the requirements of the three modern theories in a classical manner. The paper discusses basic aspects of relativity and electrodynamics. However the focus of the paper is on quantum mechanics.
Mathematical model I. Electron and quantum mechanics
Directory of Open Access Journals (Sweden)
Nitin Ramchandra Gadre
2011-03-01
Full Text Available The basic particle electron obeys various theories like electrodynamics, quantum mechanics and special relativity. Particle under different experimental conditions behaves differently, allowing us to observe different characteristics which become basis for these theories. In this paper, we have made an attempt to suggest a classical picture by studying the requirements of these three modern theories. The basic presumption is: There must be certain structural characteristics in a particle like electron which make it obey postulates of modern theories. As it is ‘difficult’ to find structure of electron experimentally, we make a mathematical attempt. For a classical approach, we require well defined systems and we have studied a system with two charged particles, proton and electron in a hydrogen atom. An attempt has been made to give a model to describe electron as seen by the proton. We then discuss how the model can satisfy the requirements of the three modern theories in a classical manner. The paper discusses basic aspects of relativity and electrodynamics. However the focus of the paper is on quantum mechanics.
A NEW SOLUTION MODEL OF NONLINEAR DYNAMIC LEAST SQUARE ADJUSTMENT
Institute of Scientific and Technical Information of China (English)
陶华学; 郭金运
2000-01-01
The nonlinear least square adjustment is a head object studied in technology fields. The paper studies on the non-derivative solution to the nonlinear dynamic least square adjustment and puts forward a new algorithm model and its solution model. The method has little calculation load and is simple. This opens up a theoretical method to solve the linear dynamic least square adjustment.
TDH solution of the Suzuki model of nuclear monopole oscillation
Skalski, J.
1987-09-01
The exact time-dependent Hartree solution of the schematic model describing nuclear monopole oscillation — the Suzuki model — is presented. The energies of vibrational states are quantized according to the gauge-invariant periodic quantization prescription.
The PRIME model: a management solution in academic medicine ...
African Journals Online (AJOL)
The PRIME model: a management solution in academic medicine. ... School of Medicine, measured against the background of good management practices. ... the principles of the PRIME model in other Medical Schools in South Africa in order ...
Exact analytic solutions for a Dirac electron moving in graphene under magnetic fields.
Kuru, S; Negro, J; Nieto, L M
2009-11-11
Exact analytical solutions for the bound states of a graphene Dirac electron in various magnetic fields with translational symmetry are obtained. In order to solve the time-independent Dirac-Weyl equation the factorization method used in supersymmetric quantum mechanics is adapted to this problem. The behavior of the discrete spectrum, probability and current densities are discussed.
Electronic Structure of Aqueous Solutions: Bridging the Gap Between Theory and Experiments
Energy Technology Data Exchange (ETDEWEB)
Pham, Tuan Anh; Govoni, Marco; Seidel, Robert; Bradforth, Stephen E.; Schwegler, Eric; Galli, Giulia
2017-06-01
Predicting the electronic properties of aqueous liquids has been a long-standing challenge for quantum mechanical methods. However, it is a crucial step in understanding and predicting the key role played by aqueous solutions and electrolytes in a wide variety of emerging energy and environmental technologies, including battery and photoelectrochemical cell design. We propose an efficient and accurate approach to predict the electronic properties of aqueous solutions, on the basis of the combination of first-principles methods and experimental validation using state-of-the-art spectroscopic measurements. We present results of the photoelectron spectra of a broad range of solvated ions, showing that first-principles molecular dynamics simulations and electronic structure calculations using dielectric hybrid functionals provide a quantitative description of the electronic properties of the solvent and solutes, including excitation energies. The proposed computational framework is general and applicable to other liquids, thereby offering great promise in understanding and engineering solutions and liquid electrolytes for a variety of important energy technologies.
Model Order Reduction for Electronic Circuits:
DEFF Research Database (Denmark)
Hjorth, Poul G.; Shontz, Suzanne
Electronic circuits are ubiquitous; they are used in numerous industries including: the semiconductor, communication, robotics, auto, and music industries (among many others). As products become more and more complicated, their electronic circuits also grow in size and complexity. This increased ...... in the semiconductor industry. Circuit simulation proceeds by using Maxwell’s equations to create a mathematical model of the circuit. The boundary element method is then used to discretize the equations, and the variational form of the equations are then solved on the graph network....
Accuracy of three electronic apex locators in the presence of different irrigating solutions.
Carvalho, Ana Laura Pion; Moura-Netto, Cacio; Moura, Abilio Albuquerque Maranhão de; Marques, Márcia Martins; Davidowicz, Harry
2010-01-01
The present study compared the accuracy of three electronic apex locators (EALs) - Elements Diagnostic®, Root ZX® and Apex DSP® - in the presence of different irrigating solutions (0.9% saline solution and 1% sodium hypochlorite). The electronic measurements were carried out by three examiners, using twenty extracted human permanent maxillary central incisors. A size 10 K file was introduced into the root canals until reaching the 0.0 mark, and was subsequently retracted to the 1.0 mark. The gold standard (GS) measurement was obtained by combining visual and radiographic methods, and was set 1 mm short of the apical foramen. Electronic length values closer to the GS (± 0.5 mm) were considered as accurate measures. Intraclass correlation coefficients (ICCs) were used to verify inter-examiner agreement. The comparison among the EALs was performed using the McNemar and Kruskal-Wallis tests (p 0.05), independent of the irrigating solutions used. The measurements taken with these two EALs were more accurate than those taken with Apex DSP®, regardless of the irrigating solution used (p locators are able to locate the cementum-dentine junction more precisely than Apex DSP®. The presence of irrigating solutions does not interfere with the performance of the EALs.
Accuracy of three electronic apex locators in the presence of different irrigating solutions
Directory of Open Access Journals (Sweden)
Ana Laura Pion Carvalho
2010-12-01
Full Text Available The present study compared the accuracy of three electronic apex locators (EALs - Elements Diagnostic®, Root ZX® and Apex DSP® - in the presence of different irrigating solutions (0.9% saline solution and 1% sodium hypochlorite. The electronic measurements were carried out by three examiners, using twenty extracted human permanent maxillary central incisors. A size 10 K file was introduced into the root canals until reaching the 0.0 mark, and was subsequently retracted to the 1.0 mark. The gold standard (GS measurement was obtained by combining visual and radiographic methods, and was set 1 mm short of the apical foramen. Electronic length values closer to the GS (± 0.5 mm were considered as accurate measures. Intraclass correlation coefficients (ICCs were used to verify inter-examiner agreement. The comparison among the EALs was performed using the McNemar and Kruskal-Wallis tests (p 0.05, independent of the irrigating solutions used. The measurements taken with these two EALs were more accurate than those taken with Apex DSP®, regardless of the irrigating solution used (p < 0.05. It was concluded that Elements Diagnostic® and Root ZX® apex locators are able to locate the cementum-dentine junction more precisely than Apex DSP®. The presence of irrigating solutions does not interfere with the performance of the EALs.
Renormalized New Solutions for the Massless Thirring Model
Casana, R.
We present a nonperturbative study of the (1+1)-dimensional massless Thirring model by using path integral methods. The regularization ambiguities — coming from the computation of the fermionic determinant — allow to find new solution types for the model. At quantum level the Ward identity for the 1PI 2-point function for the fermionic current separates such solutions in two phases or sectors, the first one has a local gauge symmetry that is implemented at quantum level and the other one without this symmetry. The symmetric phase is a new solution which is unrelated to the previous studies of the model and, in the nonsymmetric phase there are solutions that for some values of the ambiguity parameter are related to well-known solutions of the model. We construct the Schwinger-Dyson equations and the Ward identities. We make a detailed analysis of their UV divergence structure and, after, we perform a nonperturbative regularization and renormalization of the model.
Solute based Lagrangian scheme in modeling the drying process of soft matter solutions.
Meng, Fanlong; Luo, Ling; Doi, Masao; Ouyang, Zhongcan
2016-02-01
We develop a new dynamical model to study the drying process of a droplet of soft matter solutions. The model includes the processes of solute diffusion, gel-layer formation and cavity creation. A new scheme is proposed to handle the diffusion dynamics taking place in such processes. In this scheme, the dynamics is described by the motion of material points taken on solute. It is convenient to apply this scheme to solve problems that involve moving boundaries and phase changes. As an example, we show results of a numerical calculation for a drying spherical droplet, and discuss how initial concentration and evaporation rate affect the structural evolution of the droplet.
Rotkiewicz, Krystyna; Rettig, Wolfgang; Köhler, Gottfried; Rechthaler, Karl; Danel, Andrzej; Grabka, Danuta
2004-12-01
Some extended electron donor and acceptor substituted π-electron systems, composed of a dimethyl- or diethylanilino (DMA or DEA, respectively) group as electron donor and bis-pyrazoloquinoline (DPPQ) or bis-pyrazolopyridine (DMPP) derivatives as acceptors, were studied with the aim to elucidate the contributions of various solute interactions with solvent molecules upon intramolecular charge separation. Steady state and time resolved fluorescence studies were performed for DMA-DPPQ, DMA-DMPP and DEA-DMPP in alcohols and their binary mixtures with heptane. The decay kinetics of the fluorescence of DMA-DPPQ was also studied in neat 1-propanol in dependence of the temperature between 170 and 293 K. Several different fluorescent species, which were ascribed to different complexes with alcohol molecules, contribute to the fluorescence of the various compounds in these binary mixtures and account for the complex fluorescence decay. A simplified consecutive model is proposed to explain the decay behaviour of the excited species.
A multi-term solution of the space-time Boltzmann equation for electrons in gaseous and liquid Argon
Boyle, G J; Tattersall, W J; McEachran, R P; White, R D
2015-01-01
In a recent paper [1] the scattering and transport of excess electrons in liquid argon in the hydrodynamic regime was investigated, generalizing the seminal works of Lekner and Cohen [2,3] with modern scattering theory techniques and kinetic theory. In this paper, the discussion is extended to the non-hydrodynamic regime through the development of a full multi-term space-time solution of Boltzmann's equation for electron transport in gases and liquids using a novel operator-splitting method. A Green's function formalism is considered that enables flexible adaptation to various experimental systems. The spatio-temporal evolution of electrons in liquids in the hydrodynamic regime is studied for a benchmark model Percus-Yevick liquid as well as for liquid argon. The temporal evolution of Franck-Hertz oscillations are observed for liquids, with striking differences in the spatio-temporal development of the velocity distribution function components between the uncorrelated gas and true liquid approximations in arg...
Ternary interaction parameters in calphad solution models
Energy Technology Data Exchange (ETDEWEB)
Eleno, Luiz T.F., E-mail: luizeleno@usp.br [Universidade de Sao Paulo (USP), SP (Brazil). Instituto de Fisica; Schön, Claudio G., E-mail: schoen@usp.br [Universidade de Sao Paulo (USP), SP (Brazil). Computational Materials Science Laboratory. Department of Metallurgical and Materials Engineering
2014-07-01
For random, diluted, multicomponent solutions, the excess chemical potentials can be expanded in power series of the composition, with coefficients that are pressure- and temperature-dependent. For a binary system, this approach is equivalent to using polynomial truncated expansions, such as the Redlich-Kister series for describing integral thermodynamic quantities. For ternary systems, an equivalent expansion of the excess chemical potentials clearly justifies the inclusion of ternary interaction parameters, which arise naturally in the form of correction terms in higher-order power expansions. To demonstrate this, we carry out truncated polynomial expansions of the excess chemical potential up to the sixth power of the composition variables. (author)
Modeling of high-speed electronic devices
Directory of Open Access Journals (Sweden)
V. G. Kudrya
2013-09-01
Full Text Available Introduction. The theme of this publication is the modeling of electronic tools that operate in the frequency range from zero to terahertz and higher. Application of new concepts and technologies, including biotechnology and nanotechnology in the development of monolithic integrated circuits led to a backlog of technologies of projecting from technologies and experimental research and manufacturing. The aim of this work is to develop algorithms for analysis, reflecting not only topological as well as morphological properties of the object, that is designing within the framework of accounting EMI communicational transmission of energy and information in the volume of the monolithic integrated circuit. Basic steps for constructing the algorithm. The object of design is presented in the form of basic elements, which can be combined with a communication structure. The object of design is presented in the form of basic elements, which can be combined with a communication structure. There are three types of matrix equations: component; component - communication structure; communication structure. Systems of equations are reduced to standardized descriptors of mathematical model by which to understand current of poles and voltage arcs whole set of basic elements. In this way obtained mathematical model that can be implemented in CAD nano and micro technology electronics. Conclusions. Mathematical models of analysis of high-speed digital and analog electronic means. The algorithm allows morphological optimization is to minimize the adverse effects outside the system of electromagnetic interaction between the components and communicator.
Lee, Han Seung
Cryogenic electron microscopy (Cryo-EM) techniques are among the most powerful to characterize self-assembling soft materials (colloids, polymers, and microemulsions, etc.) at the nanometer scale, without any need for implicit models or assumptions about the structure. We can even visualize structure under dynamic conditions, capturing each stage of development. In this thesis, cryo-EM has been used to investigate the formation and structure of a variety of self-assembling soft materials. Visualization is complemented by small angle X-ray scattering (SAXS), dynamic light scattering, and conductivity measurements. In each case, cryo-EM provides new insights, not otherwise available, into the nanostructure development. Self-assembly phenomena at the molecular level are critical to the performance of tremendous number of applied systems ranging from personal care products to industrial products. To evaluate these self-assembled materials, multiple characterization techniques are required. We investigated aggregation behavior of cesium dodecyl sulfate (CsDS) ionic surfactant in aqueous solution. Coupled with the real space data from cryogenic transmission electron microscopy (Cryo-TEM) and the inverse space data from SAXS, the experimental result of CsDS in aqueous solution gave a new insight in CsDS micellar structures and their development as a function of concentration. Cryo-TEM showed the presence of the liquid-like hydrocarbon core in the CsDS micelles and relatively thick shell structures at a low CsDS concentration. The core-shell sphere structure micelle shifted to core-shell cylindrical micelle structure at high concentration. The morphology and structure of paclitaxel silicate (PTX) prodrug, encapsulated with amphiphilic poly(ethylene glycol)-b-poly(lactic-co-glycolic acid) diblock copolymers were studied. The six different silicate PTX prodrug candidates were characterized with cryo-TEM. Direct imaging with cryo-TEM illustrated structure of prodrug
Modeling supercritical fluid extraction process involving solute-solid interaction
Energy Technology Data Exchange (ETDEWEB)
Goto, M.; Roy, B. Kodama, A.; Hirose, T. [Kumamoto Univ., Kumamoto (Japan)
1998-04-01
Extraction or leaching of solute from natural solid material is a mass transfer process involving dissolution or release of solutes from a solid matrix. Interaction between the solute and solid matrix often influences the supercritical fluid extraction process. A model accounting for the solute-solid interaction as well as mass transfer is developed. The BET equation is used to incorporate the interaction and the solubility of solutes into the local equilibrium in the model. Experimental data for the supercritical extraction of essential oil and cuticular wax from peppermint leaves are successfully analyzed by the model. The effects of parameters on the extraction behavior are demonstrated to illustrate the concept of the model. 18 refs., 5 figs., 1 tab.
Electronic circuits modeling using artificial neural networks
Directory of Open Access Journals (Sweden)
Andrejević Miona V.
2003-01-01
Full Text Available In this paper artificial neural networks (ANN are applied to modeling of electronic circuits. ANNs are used for application of the black-box modeling concept in the time domain. Modeling process is described, so the topology of the ANN, the testing signal used for excitation, together with the complexity of ANN are considered. The procedure is first exemplified in modeling of resistive circuits. MOS transistor, as a four-terminal device, is modeled. Then nonlinear negative resistive characteristic is modeled in order to be used as a piece-wise linear resistor in Chua's circuit. Examples of modeling nonlinear dynamic circuits are given encompassing a variety of modeling problems. A nonlinear circuit containing quartz oscillator is considered for modeling. Verification of the concept is performed by verifying the ability of the model to generalize i.e. to create acceptable responses to excitations not used during training. Implementation of these models within a behavioral simulator is exemplified. Every model is implemented in realistic surrounding in order to show its interaction, and of course, its usage and purpose.
Energy Technology Data Exchange (ETDEWEB)
Chemerisov, Sergey [Argonne National Lab. (ANL), Argonne, IL (United States); Gromov, R. [Argonne National Lab. (ANL), Argonne, IL (United States); Makarashvili, Vakhtang [Argonne National Lab. (ANL), Argonne, IL (United States); Heltemes, Thad [Argonne National Lab. (ANL), Argonne, IL (United States); Sun, Zaijing [Argonne National Lab. (ANL), Argonne, IL (United States); Wardle, Kent E. [Argonne National Lab. (ANL), Argonne, IL (United States); Bailey, James [Argonne National Lab. (ANL), Argonne, IL (United States); Stepinski, Dominique [Argonne National Lab. (ANL), Argonne, IL (United States); Jerden, James [Argonne National Lab. (ANL), Argonne, IL (United States); Vandegrift, George F. [Argonne National Lab. (ANL), Argonne, IL (United States)
2015-01-30
In support of the development of accelerator-driven production of fission product Mo-99 as proposed by SHINE Medical Technologies, a 35 MeV electron linac was used to irradiate depleted-uranium (DU) uranyl sulfate dissolved in pH 1 sulfuric acid at average power densities of 6 kW, 12 kW, and 15 kW. During these irradiations, gas bubbles were generated in the solution due to the radiolytic decomposition of water molecules in the solution. Multiple video cameras were used to record the behavior of bubble generation and transport in the solution. Seven six-channel thermocouples were used to record temperature gradients in the solution from self-heating. Measurements of hydrogen and oxygen concentrations in a helium sweep gas were recorded by a gas chromatograph to estimate production rates during irradiation. These data are being used to validate a computational fluid dynamics (CFD) model of the experiment that includes multiphase flow and a custom bubble injection model for the solution region.
A quasilinear model for solute transport under unsaturated flow
Energy Technology Data Exchange (ETDEWEB)
Houseworth, J.E.; Leem, J.
2009-05-15
We developed an analytical solution for solute transport under steady-state, two-dimensional, unsaturated flow and transport conditions for the investigation of high-level radioactive waste disposal. The two-dimensional, unsaturated flow problem is treated using the quasilinear flow method for a system with homogeneous material properties. Dispersion is modeled as isotropic and is proportional to the effective hydraulic conductivity. This leads to a quasilinear form for the transport problem in terms of a scalar potential that is analogous to the Kirchhoff potential for quasilinear flow. The solutions for both flow and transport scalar potentials take the form of Fourier series. The particular solution given here is for two sources of flow, with one source containing a dissolved solute. The solution method may easily be extended, however, for any combination of flow and solute sources under steady-state conditions. The analytical results for multidimensional solute transport problems, which previously could only be solved numerically, also offer an additional way to benchmark numerical solutions. An analytical solution for two-dimensional, steady-state solute transport under unsaturated flow conditions is presented. A specific case with two sources is solved but may be generalized to any combination of sources. The analytical results complement numerical solutions, which were previously required to solve this class of problems.
Modeling and Control of a teletruck using electronic load sensing
DEFF Research Database (Denmark)
Hansen, Rico Hjerm; Iversen, Asger Malte; Jensen, Mads Schmidt;
2010-01-01
system is most commonly controlled using a hydro-mechanical control scheme called Hydraulic Load Sensing (HLS). However, with the demands for increased efficiency and controllability the HLS solutions are reaching their limits. Motivated by availability of electronic controllable fluid power...... the controller design for the ELS system, a complete model of the teletruck’s articulated arm and fluid power system is developed. To show the feasibility, a preliminary control structure for the ELS system is developed. The controller is tested on the machine, validating that features such as pump pressure...
Modeling Deterministic Chaos Using Electronic Circuits
Directory of Open Access Journals (Sweden)
T. Gotthans
2011-06-01
Full Text Available This paper brings a note on systematic circuit synthesis methods for modeling the dynamical systems given by mathematical model. Both classical synthesis and integrator based method is demonstrated via the relatively complicated real physical systems with possible chaotic solution. A variety of the different active building blocks are utilized to make the final circuits as simple as possible while preserving easily measurable voltage-mode state variables. Brief experimental verification, i.e. oscilloscope screenshots, is presented. The observed attractors have some structural stability and good relationship to their numerically integrated counterparts.
Power electronics system modeling and simulation
Energy Technology Data Exchange (ETDEWEB)
Lai, Jih-Sheng
1994-12-31
This paper introduces control system design based softwares, SIMNON and MATLAB/SIMULINK, for power electronics system simulation. A complete power electronics system typically consists of a rectifier bridge along with its smoothing capacitor, an inverter, and a motor. The system components, featuring discrete or continuous, linear or nonlinear, are modeled in mathematical equations. Inverter control methods,such as pulse-width-modulation and hysteresis current control, are expressed in either computer algorithms or digital circuits. After describing component models and control methods, computer programs are then developed for complete systems simulation. Simulation results are mainly used for studying system performances, such as input and output current harmonics, torque ripples, and speed responses. Key computer programs and simulation results are demonstrated for educational purposes.
Modelling the inelastic scattering of fast electrons
Energy Technology Data Exchange (ETDEWEB)
Allen, L.J., E-mail: lja@unimelb.edu.au [School of Physics, University of Melbourne, Parkville, Victoria 3010 (Australia); D' Alfonso, A.J., E-mail: a.j@dalfonso.com.au [School of Physics, University of Melbourne, Parkville, Victoria 3010 (Australia); Findlay, S.D. [School of Physics, Monash University, Clayton, Victoria 3800 (Australia)
2015-04-15
Imaging at atomic resolution based on the inelastic scattering of electrons has become firmly established in the last three decades. Harald Rose pioneered much of the early theoretical work on this topic, in particular emphasising the role of phase and the importance of a mixed dynamic form factor. In this paper we review how the modelling of inelastic scattering has subsequently developed and how numerical implementation has been achieved. A software package μSTEM is introduced, capable of simulating various imaging modes based on inelastic scattering in both scanning and conventional transmission electron microscopy. - Highlights: • Harald Rose was a pioneer of important work on atomic resolution imaging using inelastic scattering. • We review how the modelling of inelastic scattering has subsequently developed and been applied. • A software package μSTEM is introduced, capable of simulating various inelastic imaging modes.
Regularity of solutions of a phase field model
Amler, Thomas
2013-01-01
Phase field models are widely-used for modelling phase transition processes such as solidification, freezing or CO2 sequestration. In this paper, a phase field model proposed by G. Caginalp is considered. The existence and uniqueness of solutions are proved in the case of nonsmooth initial data. Continuity of solutions with respect to time is established. In particular, it is shown that the governing initial boundary value problem can be considered as a dynamical system. © 2013 International Press.
Modelling environmental dynamics. Advances in goematic solutions
Energy Technology Data Exchange (ETDEWEB)
Paegelow, Martin [Toulouse-2 Univ., 31 (France). GEODE UMR 5602 CNRS; Camacho Olmedo, Maria Teresa (eds.) [Granada Univ (Spain). Dpto. de Analisis Geografico Regional y Geografia Fisica
2008-07-01
Modelling environmental dynamics is critical to understanding and predicting the evolution of the environment in response to the large number of influences including urbanisation, climate change and deforestation. Simulation and modelling provide support for decision making in environmental management. The first chapter introduces terminology and provides an overview of methodological modelling approaches which may be applied to environmental and complex dynamics. Based on this introduction this book illustrates various models applied to a large variety of themes: deforestation in tropical regions, fire risk, natural reforestation in European mountains, agriculture, biodiversity, urbanism, climate change and land management for decision support, etc. These case studies, provided by a large international spectrum of researchers and presented in a uniform structure, focus particularly on methods and model validation so that this book is not only aimed at researchers and graduates but also at professionals. (orig.)
Analytical solutions for the Rabi model
Yu, Lixian; Liang, Qifeng; Chen, Gang; Jia, Suotang
2012-01-01
The Rabi model that describes the fundamental interaction between a two-level system with a quantized harmonic oscillator is one of the simplest and most ubiquitous models in modern physics. However, this model has not been solved exactly because it is hard to find a second conserved quantity besides the energy. Here we present a unitary transformation to map this unsolvable Rabi model into a solvable Jaynes-Cummings-like model by choosing a proper variation parameter. As a result, the analytical energy spectrums and wavefunctions including both the ground and the excited states can be obtained easily. Moreover, these explicit results agree well with the direct numerical simulations in a wide range of the experimental parameters. In addition, based on our obtained energy spectrums, the recent experimental observation of Bloch-Siegert in the circuit quantum electrodynamics with the ultrastrong coupling can be explained perfectly. Our results have the potential application in the solid-state quantum information...
The WITCH Model. Structure, Baseline, Solutions.
Energy Technology Data Exchange (ETDEWEB)
Bosetti, V.; Massetti, E.; Tavoni, M.
2007-07-01
WITCH - World Induced Technical Change Hybrid - is a regionally disaggregated hard link hybrid global model with a neoclassical optimal growth structure (top down) and an energy input detail (bottom up). The model endogenously accounts for technological change, both through learning curves affecting prices of new vintages of capital and through R and D investments. The model features the main economic and environmental policies in each world region as the outcome of a dynamic game. WITCH belongs to the class of Integrated Assessment Models as it possesses a climate module that feeds climate changes back into the economy. In this paper we provide a thorough discussion of the model structure and baseline projections. We report detailed information on the evolution of energy demand, technology and CO2 emissions. Finally, we explicitly quantifiy the role of free riding in determining the emissions scenarios. (auth)
Eikonal solutions to optical model coupled-channel equations
Cucinotta, Francis A.; Khandelwal, Govind S.; Maung, Khin M.; Townsend, Lawrence W.; Wilson, John W.
1988-01-01
Methods of solution are presented for the Eikonal form of the nucleus-nucleus coupled-channel scattering amplitudes. Analytic solutions are obtained for the second-order optical potential for elastic scattering. A numerical comparison is made between the first and second order optical model solutions for elastic and inelastic scattering of H-1 and He-4 on C-12. The effects of bound-state excitations on total and reaction cross sections are also estimated.
Heterojunction oxide thin-film transistors with unprecedented electron mobility grown from solution
Faber, Hendrik; Das, Satyajit; Lin, Yen-Hung; Pliatsikas, Nikos; Zhao, Kui; Kehagias, Thomas; Dimitrakopulos, George; Amassian, Aram; Patsalas, Panos A.; Anthopoulos, Thomas D.
2017-01-01
Thin-film transistors made of solution-processed metal oxide semiconductors hold great promise for application in the emerging sector of large-area electronics. However, further advancement of the technology is hindered by limitations associated with the extrinsic electron transport properties of the often defect-prone oxides. We overcome this limitation by replacing the single-layer semiconductor channel with a low-dimensional, solution-grown In2O3/ZnO heterojunction. We find that In2O3/ZnO transistors exhibit band-like electron transport, with mobility values significantly higher than single-layer In2O3 and ZnO devices by a factor of 2 to 100. This marked improvement is shown to originate from the presence of free electrons confined on the plane of the atomically sharp heterointerface induced by the large conduction band offset between In2O3 and ZnO. Our finding underscores engineering of solution-grown metal oxide heterointerfaces as an alternative strategy to thin-film transistor development and has the potential for widespread technological applications. PMID:28435867
Directory of Open Access Journals (Sweden)
Popeangã Vasile Nicolae
2010-07-01
Full Text Available European Union enlargement, the existence of new needs and demands, requires the development of innovation and quality of public administration, which means improving public services in the global economy as a requirement of competitiveness. The European Union hopes to achieve the major objectives in what concerns the electronic government by 2010; actions necessary to achieve them are adopting solutions based on information and communication technologies in the Romanian public administration, aimed at developing modern public services. This paper presents some best experiences of e-governance in Romania and the results of e-governance in Gorj County, and the degree of implementation and use by citizens.
Directory of Open Access Journals (Sweden)
Derek Mendez
2016-11-01
Full Text Available During X-ray exposure of a molecular solution, photons scattered from the same molecule are correlated. If molecular motion is insignificant during exposure, then differences in momentum transfer between correlated photons are direct measurements of the molecular structure. In conventional small- and wide-angle solution scattering, photon correlations are ignored. This report presents advances in a new biomolecular structural analysis technique, correlated X-ray scattering (CXS, which uses angular intensity correlations to recover hidden structural details from molecules in solution. Due to its intense rapid pulses, an X-ray free electron laser (XFEL is an excellent tool for CXS experiments. A protocol is outlined for analysis of a CXS data set comprising a total of half a million X-ray exposures of solutions of small gold nanoparticles recorded at the Spring-8 Ångström Compact XFEL facility (SACLA. From the scattered intensities and their correlations, two populations of nanoparticle domains within the solution are distinguished: small twinned, and large probably non-twinned domains. It is shown analytically how, in a solution measurement, twinning information is only accessible via intensity correlations, demonstrating how CXS reveals atomic-level information from a disordered solution of like molecules.
Solutions manual to accompany finite mathematics models and applications
Morris, Carla C
2015-01-01
A solutions manual to accompany Finite Mathematics: Models and Applications In order to emphasize the main concepts of each chapter, Finite Mathematics: Models and Applications features plentiful pedagogical elements throughout such as special exercises, end notes, hints, select solutions, biographies of key mathematicians, boxed key principles, a glossary of important terms and topics, and an overview of use of technology. The book encourages the modeling of linear programs and their solutions and uses common computer software programs such as LINDO. In addition to extensive chapters on pr
Nonpertubative Solutions of Massless Gauged Thirring Model
Bufalo, R.; Casana, R.; Pimentel, B. M.
2010-11-01
We present a nonperturbative quantization of the two-dimensional massless gauged Thirring model by using the path-integral approach. First, we will study the constraint structure of model via the Dirac's formalism and by using the Faddeev-Senjanovic method we calculate the vacuum-vacuum transition amplitude in a Rξ-gauge, then we compute the Green's functions in a nonperturbative framework.
Pagliai, Marco; Mancini, Giordano; Carnimeo, Ivan; De Mitri, Nicola; Barone, Vincenzo
2017-03-05
The electronic absorption spectra of pyridine and nicotine in aqueous solution have been computed using a multistep approach. The computational protocol consists in studying the solute solvation with accurate molecular dynamics simulations, characterizing the hydrogen bond interactions, and calculating electronic transitions for a series of configurations extracted from the molecular dynamics trajectories with a polarizable QM/MM scheme based on the fluctuating charge model. Molecular dynamics simulations and electronic transition calculations have been performed on both pyridine and nicotine. Furthermore, the contributions of solute vibrational effect on electronic absorption spectra have been taken into account in the so called vertical gradient approximation. © 2016 The Authors. Journal of Computational Chemistry Published by Wiley Periodicals, Inc.
Directory of Open Access Journals (Sweden)
Rubeshan Perumal
2014-03-01
Full Text Available Background: Process analysis and expert consultation help streamline and optimise processes, but these are underutilised. The World Health Organisation (WHO recommends migration to electronic data collection by 2015, partly in response to multidrug-resistant tuberculosis (MDR-TB. We explore the influence of process analysis and iterative expert consultation, on shaping health information solutions to MDR-TB programmes.Methods: The study employs a two phase design. Phase one involves a process analysis of the South African National Tuberculosis Programme and an electronic medical records (EMR solution and the generation of a detailed process model grounded in the fit between individual task and technology (FITT theoretical framework using ‘business process modelling notation’. Phase two involves a two round Delphi study in the clinical management of tuberculosis and implementers of EMR solutions. Expert opinion is analysed according to emergent thematic content. Analyses and graphical model representation are performed using Microsoft Excel® and Visio® software.Results: A detailed process model is constructed which reveals 54 break points, 12 gaps, 3 risks, 5 wastes. Five participants are included in the Delphi study which support the findings of the process analysis. Thematic analysis identifies five themes: the individual, the process, technology, capacity, and collaboration. The opportunity to include synergistic relations across programmes emerges as a strong theme.Conclusions: Overall, the findings highlight inefficiencies, risk and gaps in the current process and the need for an operational excellence intervention. The study demonstrated the value of process engineering with iterative expert consultation toward developing a meaningful EMR solution consultation in a resource constrained, developing world context.
Analytical solutions of the lattice Boltzmann BGK model
Zou, Q; Doolen, G D; Zou, Qisu; Hou, Shuling; Doolen, Gary D.
1995-01-01
Abstract: Analytical solutions of the two dimensional triangular and square lattice Boltzmann BGK models have been obtained for the plain Poiseuille flow and the plain Couette flow. The analytical solutions are written in terms of the characteristic velocity of the flow, the single relaxation time representation of these two flows without any approximation.
Positive Solutions for a Competition Model with an Inhibitor Involved
Institute of Scientific and Technical Information of China (English)
Bin Chen
2008-01-01
In the paper, we study the positive solutions of a diffusive competition model with an inhibitor involved subject to the homogeneous Dirichlet boundary condition. The existence, uniqueness, stability and multiplicity of positive solutions are discussed. This is mainly done by using the local and global bifurcation theory.
Organization and identification of solutions in the time-delayed Mackey-Glass model
Amil, Pablo; Cabeza, Cecilia; Masoller, Cristina; Martí, Arturo C.
2015-04-01
Multistability in the long term dynamics of the Mackey-Glass (MG) delayed model is analyzed by using an electronic circuit capable of controlling the initial conditions. The system's phase-space is explored by varying the parameter values of two families of initial functions. The evolution equation of the electronic circuit is derived and it is shown that, in the continuous limit, it exactly corresponds to the MG model. In practice, when using a finite set of capacitors, an excellent agreement between the experimental observations and the numerical simulations is manifested. As the delay is increased, different periodic or aperiodic solutions appear. We observe abundant periodic solutions that have the same period but a different alternation of peaks of dissimilar amplitudes and propose a novel symbolic method to classify these solutions.
Organization and identification of solutions in the time-delayed Mackey-Glass model
Energy Technology Data Exchange (ETDEWEB)
Amil, Pablo; Cabeza, Cecilia; Martí, Arturo C. [Facultad de Ciencias, Universidad de la República, Igua 4225, Montevideo (Uruguay); Masoller, Cristina [Departament de Fisica i Enginyeria Nuclear, Universitat Politecnica de Catalunya, Colom 11, E-08222 Terrassa, Barcelona (Spain)
2015-04-15
Multistability in the long term dynamics of the Mackey-Glass (MG) delayed model is analyzed by using an electronic circuit capable of controlling the initial conditions. The system's phase-space is explored by varying the parameter values of two families of initial functions. The evolution equation of the electronic circuit is derived and it is shown that, in the continuous limit, it exactly corresponds to the MG model. In practice, when using a finite set of capacitors, an excellent agreement between the experimental observations and the numerical simulations is manifested. As the delay is increased, different periodic or aperiodic solutions appear. We observe abundant periodic solutions that have the same period but a different alternation of peaks of dissimilar amplitudes and propose a novel symbolic method to classify these solutions.
Electronic Properties of Functional Biomolecules at Metal/Aqueous Solution Interfaces
DEFF Research Database (Denmark)
Zhang, Jingdong; Chi, Qijin; Kuznetsov, A.M.
2002-01-01
in electronic properties and stochastic single-molecule features and can be probed by new methods which approach the single-molecule level. Olle of these is in situ scanning tunneling microscopy (STM) in which single-molecule electronic properties directly in aqueous solution are probed. In situ STM combined...... with physical electrochemistry, single-crystal electrodes, and spectroscopic methods is now a new dimension in interfacial bioelectrochemistry. We overview first same approaches to spectroscopic single-molecule imaging, including fluorescence spectroscopy, chemical reaction dynamics, atomic force microscopy...
Periodic Solutions of a Model of Mitosis in Frog Eggs
Institute of Scientific and Technical Information of China (English)
Bei-ye Feng; Zuo-huan Zheng
2002-01-01
In this paper,we discuss a simplified model of mitosis in frog eggs proposed by M.T. Borisuk and J.J.Tyson in [1]. By using rigorous qualitative analysis, we prove the existence of the periodic solutions on a large scale and present the space region of the periodic solutions and the parameter region coresponding to the periodic solution. We also present the space region and the parameter region where there are no periodic solutions. The results are in accordance with the numerical results in [1] up to the qualitative property.
One-electron singular spectral features of the 1D Hubbard model at finite magnetic field
Carmelo, J. M. P.; Čadež, T.
2017-01-01
The momentum, electronic density, spin density, and interaction dependences of the exponents that control the (k , ω)-plane singular features of the σ = ↑ , ↓ one-electron spectral functions of the 1D Hubbard model at finite magnetic field are studied. The usual half-filling concepts of one-electron lower Hubbard band and upper Hubbard band are defined in terms of the rotated electrons associated with the model Bethe-ansatz solution for all electronic density and spin density values and the whole finite repulsion range. Such rotated electrons are the link of the non-perturbative relation between the electrons and the pseudofermions. Our results further clarify the microscopic processes through which the pseudofermion dynamical theory accounts for the one-electron matrix elements between the ground state and excited energy eigenstates.
Local Existence of Smooth Solutions to the FENE Dumbbell Model
Institute of Scientific and Technical Information of China (English)
Ge YANG
2012-01-01
The author proves the local existence of smooth solutions to the finite extensible nonlinear elasticity (FENE) dumbbell model of polymeric flows in some weighted spaces if the non-dimensional parameter b ＞ 2.
On black hole solutions in model with anisotropic fluid
Dehnen, H; Melnikov, V N
2003-01-01
A family of spherically symmetric solutions in the model with 1-component anisotropic fluid is considered. The metric of the solution depends on a parameter q > 0 relating radial pressure and the density and contains n -1 parameters corresponding to Ricci-flat ``internal space'' metrics. For q = 1 and certain equations of state the metric coincides with the metric of black brane solutions in the model with antisymmetric form. A family of black hole solutions corresponding to natural numbers q = 1,2, ... is singled out. Certain examples of solutions (e.g. containing for q =1 Reissner-Nordstr\\"{o}m, M2 and M5 black brane metrics) are considered. The post-Newtonian parameters beta and gamma corresponding to the 4-dimensional section of the metric are calculated.
Modelling elliptically polarised Free Electron Lasers
Henderson, J R; Freund, H P; McNeil, B W J
2016-01-01
A model of a Free Electron Laser operating with an elliptically polarised undulator is presented. The equations describing the FEL interaction, including resonant harmonic radiation fields, are averaged over an undulator period and generate a generalised Bessel function scaling factor, similar to that of planar undulator FEL theory. Comparison between simulations of the averaged model with those of an unaveraged model show very good agreement in the linear regime. Two unexpected results were found. Firstly, an increased coupling to harmonics for elliptical rather than planar polarisarised undulators. Secondly, and thought to be unrelated to the undulator polarisation, a signficantly different evolution between the averaged and unaveraged simulations of the harmonic radiation evolution approaching FEL saturation.
Viscosity solutions for a polymer crystal growth model
Cardaliaguet, Pierre; Monteillet, Aurélien
2010-01-01
We prove existence of a solution for a polymer crystal growth model describing the movement of a front $(\\Gamma(t))$ evolving with a nonlocal velocity. In this model the nonlocal velocity is linked to the solution of a heat equation with source $\\delta_\\Gamma$. The proof relies on new regularity results for the eikonal equation, in which the velocity is positive but merely measurable in time and with H\\"{o}lder bounds in space. From this result, we deduce \\textit{a priori} regularity for the front. On the other hand, under this regularity assumption, we prove bounds and regularity estimates for the solution of the heat equation.
The Solution Construction of Heterotic Super-Liouville Model
Institute of Scientific and Technical Information of China (English)
YANG Zhan-Ying; ZHEN Yi
2001-01-01
We investigate the heterotic super-Liouville model on the base of the basic Lie super-algebra Osp(1|2).Using the super extension of Leznov-Saveliev analysis and Drinfeld Sokolov linear system, we construct the explicit solution of the heterotic super-Liouville system in component form. We also show that the solutions are local and periodic by calculating the exchange relation of the solution. Finally starting from the action of heterotic super-Liou ville model, we obtain the conserved current and conserved charge which possessed the BR ST properties.
Exact travelling wave solutions for some important nonlinear physical models
Indian Academy of Sciences (India)
Jonu Lee; Rathinasamy Sakthivel
2013-05-01
The two-dimensional nonlinear physical models and coupled nonlinear systems such as Maccari equations, Higgs equations and Schrödinger–KdV equations have been widely applied in many branches of physics. So, finding exact travelling wave solutions of such equations are very helpful in the theories and numerical studies. In this paper, the Kudryashov method is used to seek exact travelling wave solutions of such physical models. Further, three-dimensional plots of some of the solutions are also given to visualize the dynamics of the equations. The results reveal that the method is a very effective and powerful tool for solving nonlinear partial differential equations arising in mathematical physics.
Directory of Open Access Journals (Sweden)
Sérgio Roberto da Silva
2016-06-01
Full Text Available Colombia has been one of the first countries to introduce electronic billing process on a voluntary basis, from a traditional to a digital version. In this context, the article analyzes the electronic billing process implemented in Colombia and the advantages. Methodological research is applied, qualitative, descriptive and documentary; where the regulatory framework and the conceptualization of the model is identified; the process of adoption of electronic billing is analyzed, and finally the advantages and disadvantages of its implementation is analyzed. The findings indicate that the model applied in Colombia to issue an electronic billing in sending and receiving process, is not complex, but it requires a small adequate infrastructure and trained personnel to reach all sectors, especially the micro and business which is the largest business network in the country.
Another solution of 2D Ising model
Vergeles, S. N.
2009-04-01
The partition function of the Ising model on a two-dimensional regular lattice is calculated by using the matrix representation of a Clifford algebra (the Dirac algebra), with number of generators equal to the number of lattice sites. It is shown that the partition function over all loops in a 2D lattice including self-intersecting ones is the trace of a polynomial in terms of Dirac matrices. The polynomial is an element of the rotation group in the spinor representation. Thus, the partition function is a function of a character on an orthogonal group of a high degree in the spinor representation.
Effect of electron beam irradiation on the degradation of monochlorophenols in aqueous solution
Institute of Scientific and Technical Information of China (English)
ADELEKE Olukunle Francis; ZHOU Rui-min; Zu Jian-hua; Ekoko Bakambo Gracien
2005-01-01
Electron beam was successfully used for the degradation of 2-chlorophenol (2-CP) and 4-chlorophenol (4-CP) in aqueous solutions in this research. The effect of radiation dose on substrate degradation and dechlorination of solutions with concentration of 50 mg/L was investigated. The effect of initial concentration, pH and presence of oxygen was also investigated. The concentration of 2-CP and 4-CP remaining in solution after irradiation were measured by HPLC. The results showed that increased radiation dose led to increased degradation of the chlorophenols and increased Cl- yield. Deaeration was also found to significantly increase the rate of degradation of chlorophenols in water while degradation and dechlorination under alkaline condition was lower than at low to neutral pH.
Goldstein, Sara; Behar, David; Rajh, Tijana; Rabani, Joseph
2015-03-26
The reaction mechanism of nitric oxide (NO) reduction by excess electrons on TiO2 nanoparticles (e(TiO2)(-)) has been studied under anaerobic conditions. TiO2 was loaded with 10-130 electrons per particle using γ-irradiation of acidic TiO2 colloid solutions containing 2-propanol. The study is based on time-resolved kinetics and reactants and products analysis. The reduction of NO by e(TiO2)(-) is interpreted in terms of competition between a reaction path leading to formation of NH3 and a path leading to N2O and N2. The proposed mechanism involves consecutive one-electron transfers of NO, and its reduction intermediates HNO, NH2O(•), and NH2OH. The results show that e(TiO2)(-) does not reduce N2O and N2. Second-order rate constants of e(TiO2)(-) reactions with NO (740 ± 30 M(-1) s(-1)) and NH2OH (270 ± 30 M(-1) s(-1)) have been determined employing the rapid-mixing stopped-flow technique and that with HNO (>1.3 × 10(6) M(-1) s(-1)) was derived from fitting the kinetic traces to the suggested reaction mechanism, which is discussed in detail.
Exact solution of qubit decoherence models by a transfer matrix method
Nghiem, D; Joynt, Robert; Nghiem, Diu
2005-01-01
We present a new method for the solution of the behavior of an enesemble of qubits in a random time-dependent external field. The forward evolution in time is governed by a transfer matrix. The elements of this matrix determine the various decoherence times. The method provides an exact solution in cases where the noise is piecewise constant in time. We show that it applies, for example, to a realistic model of decoherence of electron spins in semiconductors. Results are obtained for the non-perturbative regimes of the models, and we see a transition from weak relaxation to overdamped behavior as a function of noise anisotropy.
Analysis and modeling of alkali halide aqueous solutions
DEFF Research Database (Denmark)
Kim, Sun Hyung; Anantpinijwatna, Amata; Kang, Jeong Won;
2016-01-01
A new model is proposed for correlation and prediction of thermodynamic properties of electrolyte solutions. In the proposed model, terms of a second virial coefficient-type and of a KT-UNIFAC model are used to account for a contribution of binary interactions between ion and ion, and water and ion...... on calculations for various electrolyte properties of alkali halide aqueous solutions such as mean ionic activity coefficients, osmotic coefficients, and salt solubilities. The model covers highly nonideal electrolyte systems such as lithium chloride, lithium bromide and lithium iodide, that is, systems...
Quantum Ising model coupled with conducting electrons
Energy Technology Data Exchange (ETDEWEB)
Yamashita, Yasufumi; Yonemitsu, Kenji [Institute for Molecular Science, 38 Nishigo-Naka, Myodaiji, Okazaki 444-8585 (Japan); Graduate University for Advanced studies, 38 Nishigo-Naka, Myodaiji, Okazaki 444-8585 (Japan)
2005-01-01
The effect of photo-doping on the quantum paraelectric SrTiO{sub 3} is studied by using the one-dimensional quantum Ising model, where the Ising spin describes the effective lattice polarization of an optical phonon. Two types of electron-phonon couplings are introduced through the modulation of transfer integral via lattice deformations. After the exact diagonalization and the perturbation studies, we find that photo-induced low-density carriers can drastically alter quantum fluctuations when the system locates near the quantum critical point between the quantum para- and ferro-electric phases.
Quantum Ising model coupled with conducting electrons
Yamashita, Yasufumi; Yonemitsu, Kenji
2005-01-01
The effect of photo-doping on the quantum paraelectric SrTiO3 is studied by using the one-dimensional quantum Ising model, where the Ising spin describes the effective lattice polarization of an optical phonon. Two types of electron-phonon couplings are introduced through the modulation of transfer integral via lattice deformations. After the exact diagonalization and the perturbation studies, we find that photo-induced low-density carriers can drastically alter quantum fluctuations when the system locates near the quantum critical point between the quantum para- and ferro-electric phases.
The Symmetric Solutions of Affiliated Value Model
Institute of Scientific and Technical Information of China (English)
Che Ka-jia; Li Zhi-chen
2004-01-01
In a symmetric affiliated value model, this paper analyses High-Technology industrial firms' competitive strategy in research and development (R&D). We obtain the symmetric Bayesian Nash Equilibrium functions with or without government's prize:b1(x)=v(x,x)Fn-1(x|x)-∫x0Fn-1(y|y)dv(y,y), b2(x)=∫x0[v(y,y)+v0]dFn-1(y|y), and b3(x)=∫x0v(y,y)(fn-1(y|y))/(1-Fn-1(y|y))dy. We find the firm's investment level will increase in prize, only when the constant prize v0≥v(y,y)(Fn-1(y|y))/(1-Fn-1(y|y)), does the firm invest more aggressively with constant prize than with variable prize.
Investigating multiple solutions in the constrained minimal supersymmetric standard model
Energy Technology Data Exchange (ETDEWEB)
Allanach, B.C. [DAMTP, CMS, University of Cambridge,Wilberforce Road, Cambridge, CB3 0HA (United Kingdom); George, Damien P. [DAMTP, CMS, University of Cambridge,Wilberforce Road, Cambridge, CB3 0HA (United Kingdom); Cavendish Laboratory, University of Cambridge,JJ Thomson Avenue, Cambridge, CB3 0HE (United Kingdom); Nachman, Benjamin [SLAC, Stanford University,2575 Sand Hill Rd, Menlo Park, CA 94025 (United States)
2014-02-07
Recent work has shown that the Constrained Minimal Supersymmetric Standard Model (CMSSM) can possess several distinct solutions for certain values of its parameters. The extra solutions were not previously found by public supersymmetric spectrum generators because fixed point iteration (the algorithm used by the generators) is unstable in the neighbourhood of these solutions. The existence of the additional solutions calls into question the robustness of exclusion limits derived from collider experiments and cosmological observations upon the CMSSM, because limits were only placed on one of the solutions. Here, we map the CMSSM by exploring its multi-dimensional parameter space using the shooting method, which is not subject to the stability issues which can plague fixed point iteration. We are able to find multiple solutions where in all previous literature only one was found. The multiple solutions are of two distinct classes. One class, close to the border of bad electroweak symmetry breaking, is disfavoured by LEP2 searches for neutralinos and charginos. The other class has sparticles that are heavy enough to evade the LEP2 bounds. Chargino masses may differ by up to around 10% between the different solutions, whereas other sparticle masses differ at the sub-percent level. The prediction for the dark matter relic density can vary by a hundred percent or more between the different solutions, so analyses employing the dark matter constraint are incomplete without their inclusion.
Modeling Complex Chemical Systems: Problems and Solutions
van Dijk, Jan
2016-09-01
Non-equilibrium plasmas in complex gas mixtures are at the heart of numerous contemporary technologies. They typically contain dozens to hundreds of species, involved in hundreds to thousands of reactions. Chemists and physicists have always been interested in what are now called chemical reduction techniques (CRT's). The idea of such CRT's is that they reduce the number of species that need to be considered explicitly without compromising the validity of the model. This is usually achieved on the basis of an analysis of the reaction time scales of the system under study, which identifies species that are in partial equilibrium after a given time span. The first such CRT that has been widely used in plasma physics was developed in the 1960's and resulted in the concept of effective ionization and recombination rates. It was later generalized to systems in which multiple levels are effected by transport. In recent years there has been a renewed interest in tools for chemical reduction and reaction pathway analysis. An example of the latter is the PumpKin tool. Another trend is that techniques that have previously been developed in other fields of science are adapted as to be able to handle the plasma state of matter. Examples are the Intrinsic Low Dimension Manifold (ILDM) method and its derivatives, which originate from combustion engineering, and the general-purpose Principle Component Analysis (PCA) technique. In this contribution we will provide an overview of the most common reduction techniques, then critically assess the pros and cons of the methods that have gained most popularity in recent years. Examples will be provided for plasmas in argon and carbon dioxide.
Model of electron pairs in electron-doped cuprates
Singh, R. J.; Khan, Shakeel
2016-07-01
In the order parameter of hole-doped cuprate superconductors in the pseudogap phase, two holes enter the order parameter from opposite sides and pass through various CuO2 cells jumping from one O2- to the other under the influence of magnetic field offered by the Cu2+ ions in that CuO2 cell and thus forming hole pairs. In the pseudogap phase of electron-doped cuprates, two electrons enter the order parameter at Cu2+ sites from opposite ends and pass from one Cu2+ site to the diagonally opposite Cu2+ site. Following this type of path, they are subjected to high magnetic fields from various Cu2+ ions in that cell. They do not travel from one Cu2+ site to the other along straight path but by helical path. As they pass through the diagonal, they face high to low to very high magnetic field. Therefore, frequency of helical motion and pitch goes on changing with the magnetic field. Just before reaching the Cu2+ ions at the exit points of all the cells, the pitch of the helical motion is enormously decreased and thus charge density at these sites is increased. So the velocity of electrons along the diagonal path is decreased. Consequently, transition temperature of electron-doped cuprates becomes less than that of hole-doped cuprates. Symmetry of the order parameter of the electron-doped cuprates has been found to be of 3dx2-y2 + iS type. It has been inferred that internal magnetic field inside the order parameter reconstructs the Fermi surface, which is requisite for superconductivity to take place. Electron pairs formed in the pseudogap phase are the precursors of superconducting order parameter when cooled below Tc.
Oliver, Thomas A A; Zhang, Yuyuan; Roy, Anirban; Ashfold, Michael N R; Bradforth, Stephen E
2015-10-15
The excited state dynamics of phenol in water have been investigated using transient absorption spectroscopy. Solvated electrons and vibrationally cold phenoxyl radicals are observed upon 200 and 267 nm excitation, but with formation time scales that differ by more than 4 orders of magnitude. The impact of these findings is assessed in terms of the relative importance of autoionization versus proton-coupled electron transfer mechanisms in this computationally tractable model system.
Stability of core-shell nanowires in selected model solutions
Kalska-Szostko, B.; Wykowska, U.; Basa, A.; Zambrzycka, E.
2015-03-01
This paper presents the studies of stability of magnetic core-shell nanowires prepared by electrochemical deposition from an acidic solution containing iron in the core and modified surface layer. The obtained nanowires were tested according to their durability in distilled water, 0.01 M citric acid, 0.9% NaCl, and commercial white wine (12% alcohol). The proposed solutions were chosen in such a way as to mimic food related environment due to a possible application of nanowires as additives to, for example, packages. After 1, 2 and 3 weeks wetting in the solutions, nanoparticles were tested by Infrared Spectroscopy, Atomic Absorption Spectroscopy, Transmission Electron Microscopy and X-ray diffraction methods.
Stepanov, Nikolay S.; Zelekson, Lev A.
2017-03-01
The exact stationary solution of one-dimensional non-relativistic Vlasov equation is obtained in the article. It is shown that in the energy exchange with the self-consistent longitudinal electric field, both wave trapped charged particles and the passing ones take part. It is proved that the trapped electron distribution is fundamentally different from distribution functions described by other authors, which used the Bernstein, Greene, and Kruskal method. So, the correct distribution function is characterized by its sudden change at the equality of wave and electrons' velocity but not on the edges of the potential well. This jump occurs for any arbitrary small value of wave potential. It was also found that the energy density of fast electrons trapped by the wave is less than the energy density of slow trapped electrons. This leads to the fact that the energy of the self-consistent electric field may both increase and decrease due to the nonlinear Landau damping. The conditions under which a similar effect can be observed are defined. Also for the first time, it is shown that the self-generated strong electric field always produces antitropic electron beams.
Directory of Open Access Journals (Sweden)
Suvorova E. I.
2001-01-01
Full Text Available Calcium phosphate precipitation obtained from aqueous solutions at room and body temperature and pH 5.5-7.5 were investigated by high-resolution transmission electron microscopy (HRTEM, transmission electron diffraction, scanning electron microscopy (SEM and X-ray diffraction (XRD. Supersaturated solutions of calcium phosphates were prepared by different methods of mixing of the stock solutions: diffusion-controlled mixing in space, convection-controlled mixing on earth and forced mixing on earth and with typical physiological parameters (pH and temperature. Concentrations of the stock solutions, rate of solution mixing and duration of precipitation influence very strongly the chemical composition of the precipitation, the phase composition of individual crystals, their sizes, morphology and structure. Microdiffraction and HRTEM techniques showed an incontestable advantage on other techniques like SEM and XRD in the investigation of small particles and mixtures of calcium phosphates (hydroxyapatite and octacalcium phosphate with different proportions.
Mushy-zone model with an exact solution
Energy Technology Data Exchange (ETDEWEB)
Solomon, A. D.; Wilson, D. G.; Alexiades, V.
1982-04-01
In this paper we propose a very simple model of a mushy zone which admits of an explicit solution. To our knowledge, it is the only instance where an actual observation of the mushy zone width and structure is used as a partial basis for the model definition. The model rests upon two unknown parameters. The first determines the relation between the equilibrium temperature gradient and the mushy zone width. The second depends upon the dendritic structure in the mushy zone, and is related to the solid fraction. Both can be estimated from experiments. We will limit ourselves to defining the model, presenting its closed form solution, and giving tables from which the solution can be found explicitly. It is shown that in most cases the predicted mushy zone is of very negligible importance.
Modeling of CO2 absorber using an AMP solution
DEFF Research Database (Denmark)
Gabrielsen, Jostein; Michelsen, Michael Locht; Stenby, Erling Halfdan
2006-01-01
Abstract: An explicit model for carbon dioxide (CO2) solubility in an aqueous solution of 2-amino-2-methyl-1-propanol (AMP) has been proposed and an expression for the heat of absorption of CO2 has been developed as a function of loading and temperature. A rate-based steady-state model for CO2 ab...
Anisotropic static solutions in modelling highly compact bodies
Indian Academy of Sciences (India)
M Chaisi; S D Maharaj
2006-03-01
Einstein field equations for static anisotropic spheres are solved and exact interior solutions obtained. This paper extends earlier treatments to include anisotropic models which accommodate a wider variety of physically viable energy densities. Two classes of solutions are possible. The first class contains the limiting case ∝ -2 for the energy density which arises in many astrophysical applications. In the second class the singularity at the centre of the star is not present in the energy density
Energy Technology Data Exchange (ETDEWEB)
Xie, Ming [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
2000-05-18
Exact solution and variational approximation of eigenmodes in high gain FELs are presented. These eigenmodes specify transverse profiles and exponential growth rates of the laser field before saturation. They are self-consistent solutions of coupled Maxwell–Vlasov equations describing FEL interaction taking into account the effects due to energy spread, emittance and betatron oscillations of the electron beam, as well as diffraction and optical guiding of the laser field. A new formalism of scaling is introduced and based on which solutions in various limiting cases are discussed. Additionally, a fitting formula is obtained from interpolating the variational solution for quick calculation of exponential growth rate of the fundamental mode.
Lu, Jibao; Dai, Ying; Guo, Meng; Wei, Wei; Ma, Yandong; Han, Shenghao; Huang, Baibiao
2012-01-16
As an excellent bandgap-engineering material, the Cd(1-x)Zn(x)S solid solution, is found to be an efficient visible light response photocatalyst for water splitting, but few theoretical studies have been performed on it. A better characterization of the composition dependence of the physical and optical properties of this material and a thorough understanding of the bandgap-variation mechanism are necessary to optimize the design of high-efficience photocatalysts. In order to get an insight into these problems, we systematically investigated the crystal structure, the phase stability, and the electronic structures of the Cd(1-x)Zn(x)S solid solution by means of density functional theory calculations. The most energetically favorable arrangement of the Cd, Zn, S atoms and the structural disorder of the solid solution are revealed. The phase diagram of the Cd(1-x)Zn(x)S solid solution is calculated based on regular-solution model and compared with the experimental data. This is the first report on the calculated phase diagram of this solid solution, and can give guidance for the experimental synthesis of this material. Furthermore, the variation of the electronic structures versus x and its mechanism are elaborated in detail, and the experimental bandgap as a function of x is well predicted. Our findings provide important insights into the experimentally observed structural and electronic properties, and can give theoretical guidelines for the further design of the Cd(1-x)Zn(x)S solid solution.
Matrix models with hard walls: geometry and solutions
Energy Technology Data Exchange (ETDEWEB)
Chekhov, L [Steklov Mathematical Institute, Moscow (Russian Federation); Institute for Theoretical and Experimental Physics, Moscow (Russian Federation); Poncelet Laboratoire International Franco-Russe, Moscow (Russian Federation); Department of Mathematics and Statistics, Concordia University, Montreal (Canada)
2006-07-14
We discuss various aspects of most general multisupport solutions to matrix models in the presence of hard walls, i.e., in the case where the eigenvalue support is confined to subdomains of the real axis. The structure of the solution at the leading order is described by semiclassical or generalized Whitham-Krichever hierarchies as in the unrestricted case. Derivatives of tau-functions for these solutions are associated with families of Riemann surfaces (with possible double points) and satisfy the Witten-Dijkgraaf-Verlinde-Verlinde equations. We then develop the diagrammatic technique for finding free energy of this model in all orders of the 't Hooft expansion in the reciprocal matrix size generalizing the Feynman diagrammatic technique for the Hermitian one-matrix model due to Eynard.
Yamazawa, Toshiko; Nakamura, Naotoshi; Sato, Mari; Sato, Chikara
2016-12-01
Exocrine glands, e.g., salivary and pancreatic glands, play an important role in digestive enzyme secretion, while endocrine glands, e.g., pancreatic islets, secrete hormones that regulate blood glucose levels. The dysfunction of these secretory organs immediately leads to various diseases, such as diabetes or Sjögren's syndrome, by poorly understood mechanisms. Gland-related diseases have been studied by optical microscopy (OM), and at higher resolution by transmission electron microscopy (TEM) of Epon embedded samples, which necessitates hydrophobic sample pretreatment. Here, we report the direct observation of tissue in aqueous solution by atmospheric scanning electron microscopy (ASEM). Salivary glands, lacrimal glands, and pancreas were fixed, sectioned into slabs, stained with phosphotungstic acid (PTA), and inspected in radical scavenger d-glucose solution from below by an inverted scanning electron microscopy (SEM), guided by optical microscopy from above to target the tissue substructures. A 2- to 3-µm specimen thickness was visualized by the SEM. In secretory cells, cytoplasmic vesicles and other organelles were clearly imaged at high resolution, and the former could be classified according to the degree of PTA staining. In islets of Langerhans, the microvascular system used as an outlet by the secretory cells was also clearly observed. Microvascular system is also critically involved in the onset of diabetic complications and was clearly visible in subcutaneous tissue imaged by ASEM. The results suggest the use of in-solution ASEM for histology and to study vesicle secretion systems. Further, the high-throughput of ASEM makes it a potential tool for the diagnosis of exocrine and endocrine-related diseases.
Modeling of electron-electron collisions for particle-in-cell simulations
Energy Technology Data Exchange (ETDEWEB)
Andrea, D. d'
2006-09-15
The modeling of the physics of pulsed plasma thrusters requires the numerical solution of the Boltzmann equation for rarefied plasma flows where continuum assumptions fail. To tackle this challenging task, a cooperation between several institutes has been formed with the goal to develop a hybrid code based on Particle-In-Cell and Direct Simulation Monte Carlo techniques. These development activities are bundled in the project ''Numerische Simulation und Auslegung eines instationaeren gepulsten magnetoplasmadynamischen Triebwerks fuer eine Mondsonde'' which is funded by the Landesstiftung Baden-Wuerttemberg within the subject area ''Modellierung und Simulation auf Hochleistungscomputern''. In the frame of this project, the IHM is in charge to develop suitable physical-mathematical and numerical models to include charged particle collisions into the simulation. which can significantly affect the Parameters of such plasma devices. The intention of the present report is to introduce the Fokker-Planck approach for electron-electron interaction in Standard charged particle simulations. where the impact Parameter is usually large resulting in a small deflection angle. The theoretical and applicative framework is discussed in detail paying particular attention to the Particle-In-Cell approach in velocity space. a new technique which allows the self-consistent computation of the friction and diffusion coefficients arising from the Fokker-Planck treatment of collisions. These velocity-dependent coefficients thernselves are responsible for the change in velocity of the simulation particles, which is determined by the numerical solution of a Langevin-type equation. Simulation results for typical numerical experiments computed with the new developed Fokker-Planck solver are presented. demonstrating the quality. property and reliability of the applied numerical methods. (orig.)
Characterization and Modeling of Power Electronics Device
Directory of Open Access Journals (Sweden)
Tandjaoui Mohammed Nasser
2014-10-01
Full Text Available During the three decades spent, the advances of high voltage/current semiconductor technology directly affect the power electronics converter technology and its progress. The developments of power semiconductors led successively to the appearance of the elements such as the Thyristors, and become commercially available. The various semiconductor devices can be classified into the way they can be controlled, uncontrolled category such as the Diode when it’s on or off state is controlled by the power circuit, and second category is the fully controlled such as the Metal Oxide Semiconductor Field Effect Transistor (MOSFET, and this category can be included a new hybrid devices such as the Insulated Gate Bipolar Transistor (IGBT, and the Gate Turn-off Thyristor (GTO. This paper describes the characteristics and modeling of several types of power semiconductor devices such as MOSFET, IGBT and GTO.
Solution of time-dependent Boltzmann equation for electrons in non-thermal plasma
Energy Technology Data Exchange (ETDEWEB)
Trunec, D; Bonaventura, Z; Necas, D [Department of Physical Electronics, Faculty of Science, Masaryk University, Kotlarska 2, 611 37 Brno (Czech Republic)
2006-06-21
The time development of the electron distribution function and electron macroscopic parameters was studied by solving the time-dependent Boltzmann equation for low temperature plasma. A new technique for solving the time-dependent Boltzmann equation was developed. This technique is based on a multi-term approximation of the electron distribution function expansion in Legendre polynomials. The results for electron relaxation in Reid's ramp model and argon plasma are presented. The effect of negative mobility was studied and is discussed for argon plasma. Finally, the time-dependent Boltzmann equation was solved for pulsed microwave discharge in nitrogen. The accuracy of all results was confirmed by the Monte Carlo simulation.
Neutrinos, Electrons and Muons in Electromagnetic Fields and Matter: The Method of Exact Solutions
Kouzakov, Konstantin A
2008-01-01
We present a powerful method for exploring various processes in the presence of strong external fields and matter. The method implies utilization of the exact solutions of the modified Dirac equations which contain the effective potentials accounting for the influences of external electromagnetic fields and matter on particles. We briefly discuss the basics of the method and its applications to studies of different processes, including a recently proposed new mechanism of radiation by neutrinos and electrons moving in matter (the spin light of the neutrino and electron). In view of a recent "prediction" of an order-of-magnitude change of the muon lifetime under the influence of an electromagnetic field of a CO$_2$ laser, we revisit the issue and show that such claims are nonrealistic.
Oxidative Leaching of metals from electronic waste with solutions based on quaternary ammonium salts
Pinheiro, Diana
2009-01-01
The treatment of electric and electronic waste (WEEE) is a problem which receives ever more attention. An inadequate treatment results in harmful products ending up in the environment. This project intends to investigate the possibilities of an alternative route for recycling of metals from printed circuit boards (PCBs) obtained from rejected computers. The process is based on aqueous solutions composed of an etchant, either 0.2 M CuCl2.2H2O or 0.2 M FeCl3.6H2O, and a quater...
Pro EDI in BizTalk Server 2006 R2 electronic document interchange solutions
Beckner, Mark
2008-01-01
As business becomes more dependent on working with partners, suppliers, and other organizations in a streamlined way, Electronic Data Interchange (EDI) is one of the next big waves in connected systems. Microsoft BizTalk Server 2006 R2 offers an efficient, integrated way to deploy EDI solutions, and with the help of this book, readers will see how EDI can be used in their business and how best to get it set up with BizTalk. This book offers insights into the brand-new Biztalk 2006 R2--based EDI functionality, including the far greater flexibility in handling interchange. It gives advice coveri
Marek, A; Blum, V; Johanni, R; Havu, V; Lang, B; Auckenthaler, T; Heinecke, A; Bungartz, H-J; Lederer, H
2014-05-28
Obtaining the eigenvalues and eigenvectors of large matrices is a key problem in electronic structure theory and many other areas of computational science. The computational effort formally scales as O(N(3)) with the size of the investigated problem, N (e.g. the electron count in electronic structure theory), and thus often defines the system size limit that practical calculations cannot overcome. In many cases, more than just a small fraction of the possible eigenvalue/eigenvector pairs is needed, so that iterative solution strategies that focus only on a few eigenvalues become ineffective. Likewise, it is not always desirable or practical to circumvent the eigenvalue solution entirely. We here review some current developments regarding dense eigenvalue solvers and then focus on the Eigenvalue soLvers for Petascale Applications (ELPA) library, which facilitates the efficient algebraic solution of symmetric and Hermitian eigenvalue problems for dense matrices that have real-valued and complex-valued matrix entries, respectively, on parallel computer platforms. ELPA addresses standard as well as generalized eigenvalue problems, relying on the well documented matrix layout of the Scalable Linear Algebra PACKage (ScaLAPACK) library but replacing all actual parallel solution steps with subroutines of its own. For these steps, ELPA significantly outperforms the corresponding ScaLAPACK routines and proprietary libraries that implement the ScaLAPACK interface (e.g. Intel's MKL). The most time-critical step is the reduction of the matrix to tridiagonal form and the corresponding backtransformation of the eigenvectors. ELPA offers both a one-step tridiagonalization (successive Householder transformations) and a two-step transformation that is more efficient especially towards larger matrices and larger numbers of CPU cores. ELPA is based on the MPI standard, with an early hybrid MPI-OpenMPI implementation available as well. Scalability beyond 10,000 CPU cores for problem
Global solution for a chemotactic haptotactic model of cancer invasion
Tao, Youshan; Wang, Mingjun
2008-10-01
This paper deals with a mathematical model of cancer invasion of tissue recently proposed by Chaplain and Lolas. The model consists of a reaction-diffusion-taxis partial differential equation (PDE) describing the evolution of tumour cell density, a reaction-diffusion PDE governing the evolution of the proteolytic enzyme concentration and an ordinary differential equation modelling the proteolysis of the extracellular matrix (ECM). In addition to random motion, the tumour cells are directed not only by haptotaxis (cellular locomotion directed in response to a concentration gradient of adhesive molecules along the ECM) but also by chemotaxis (cellular locomotion directed in response to a concentration gradient of the diffusible proteolytic enzyme). In one space dimension, the global existence and uniqueness of a classical solution to this combined chemotactic-haptotactic model is proved for any chemotactic coefficient χ > 0. In two and three space dimensions, the global existence is proved for small χ/μ (where μ is the logistic growth rate of the tumour cells). The fundamental point of proof is to raise the regularity of a solution from L1 to Lp (p > 1). Furthermore, the existence of blow-up solutions to a sub-model in two space dimensions for large χ shows, to some extent, that the condition that χ/μ is small is necessary for the global existence of a solution to the full model.
Modulating Cationic Ratios for High-Performance Transparent Solution-Processed Electronics.
John, Rohit Abraham; Nguyen, Anh Chien; Chen, Yuxin; Shukla, Sudhanshu; Chen, Shi; Mathews, Nripan
2016-01-20
Amorphous oxide semiconductors such as indium zinc tin oxide (IZTO) are considered favorites to serve as channel materials for thin film transistors (TFTs) because they combine high charge carrier mobility with high optical transmittance, allowing for the development of transparent electronics. Although the influence of relative cationic concentrations in determining the electronic properties have been studied in sputtered and PLD films, the development of printed transparent electronics hinges on such dependencies being explored for solution-processed systems. Here, we study solution-processed indium zinc tin oxide thin film transistors (TFTs) to investigate variation in their electrical properties with change in cationic composition. Charge transport mobility ranging from 0.3 to 20.3 cm(2)/(V s), subthreshold swing ranging from 1.2 to 8.4 V/dec, threshold voltage ranging from -50 to 5 V, and drain current on-off ratio ranging from 3 to 6 orders of magnitude were obtained by examining different compositions of the semiconductor films. Mobility was found to increase with the incorporation of large cations such as In(3+) and Sn(4+) due to the vast s-orbital overlap they can achieve when compared to the intercationic distance. Subthreshold swing decreased with an increase in Zn(2+) concentration due to reduced interfacial state formation between the semiconductor and dielectric. The optimized transistor obtained at a compositional ratio of In/Zn/Sn = 1:1:1, exhibited a high field-effect mobility of 8.62 cm(2)/(V s), subthreshold swing of 1.75 V/dec, and current on-off ratio of 10(6). Such impressive performances reaffirm the promise of amorphous metal oxide semiconductors for printed electronics.
Kleinerman, O; Parra-Vasquez, A Nicholas G; Green, M J; Behabtu, N; Schmidt, J; Kesselman, E; Young, C C; Cohen, Y; Pasquali, M; Talmon, Y
2015-07-01
Cryogenic electron microscopy (cryo-EM) is a powerful tool for imaging liquid and semiliquid systems. While cryogenic transmission electron microscopy (cryo-TEM) is a standard technique in many fields, cryogenic scanning electron microscopy (cryo-SEM) is still not that widely used and is far less developed. The vast majority of systems under investigation by cryo-EM involve either water or organic components. In this paper, we introduce the use of novel cryo-TEM and cryo-SEM specimen preparation and imaging methodologies, suitable for highly acidic and very reactive systems. Both preserve the native nanostructure in the system, while not harming the expensive equipment or the user. We present examples of direct imaging of single-walled, multiwalled carbon nanotubes and graphene, dissolved in chlorosulfonic acid and oleum. Moreover, we demonstrate the ability of these new cryo-TEM and cryo-SEM methodologies to follow phase transitions in carbon nanotube (CNT)/superacid systems, starting from dilute solutions up to the concentrated nematic liquid-crystalline CNT phases, used as the 'dope' for all-carbon-fibre spinning. Originally developed for direct imaging of CNTs and graphene dissolution and self-assembly in superacids, these methodologies can be implemented for a variety of highly acidic systems, paving a way for a new field of nonaqueous cryogenic electron microscopy. © 2015 The Authors Journal of Microscopy © 2015 Royal Microscopical Society.
A new solution for maximal clique problem based sticker model.
Darehmiraki, Majid
2009-02-01
In this paper, we use stickers to construct a solution space of DNA for the maximal clique problem (MCP). Simultaneously, we also apply the DNA operation in the sticker-based model to develop a DNA algorithm. The results of the proposed algorithm show that the MCP is resolved with biological operations in the sticker-based model for the solution space of the sticker. Moreover, this work presents clear evidence of the ability of DNA computing to solve the NP-complete problem. The potential of DNA computing for the MCP is promising given the operational time complexity of O(nxk).
Viscosity solutions for a polymer crystal growth model
Cardaliaguet, Pierre; Ley, Olivier; Monteillet, Aurélien
2011-01-01
International audience; We prove existence of a solution for a polymer crystal growth model describing the movement of a front $(\\Gamma(t))$ evolving with a nonlocal velocity. In this model the nonlocal velocity is linked to the solution of a heat equation with source $\\delta_\\Gamma$. The proof relies on new regularity results for the eikonal equation, in which the velocity is positive but merely measurable in time and with H\\"{o}lder bounds in space. From this result, we deduce \\textit{a pri...
Combined physical and chemical nonequilibrium transport model for solution conduits.
Field, Malcolm S; Leij, Feike J
2014-02-01
Solute transport in karst aquifers is primarily constrained to relatively complex and inaccessible solution conduits where transport is often rapid, turbulent, and at times constrictive. Breakthrough curves generated from tracer tests in solution conduits are typically positively-skewed with long tails evident. Physical nonequilibrium models to fit breakthrough curves for tracer tests in solution conduits are now routinely employed. Chemical nonequilibrium processes are likely important interactions, however. In addition to partitioning between different flow domains, there may also be equilibrium and nonequilibrium partitioning between the aqueous and solid phases. A combined physical and chemical nonequilibrium (PCNE) model was developed for an instantaneous release similar to that developed by Leij and Bradford (2009) for a pulse release. The PCNE model allows for partitioning open space in solution conduits into mobile and immobile flow regions with first-order mass transfer between the two regions to represent physical nonequilibrium in the conduit. Partitioning between the aqueous and solid phases proceeds either as an equilibrium process or as a first-order process and represents chemical nonequilibrium for both the mobile and immobile regions. Application of the model to three example breakthrough curves demonstrates the applicability of the combined physical and chemical nonequilibrium model to tracer tests conducted in karst aquifers, with exceptionally good model fits to the data. The three models, each from a different state in the United States, exhibit very different velocities, dispersions, and other transport properties with most of the transport occurring via the fraction of mobile water. Fitting the model suggests the potentially important interaction of physical and chemical nonequilibrium processes.
Modeling electron transport in the presence of electric and magnetic fields.
Energy Technology Data Exchange (ETDEWEB)
Fan, Wesley C.; Drumm, Clifton Russell; Pautz, Shawn D.; Turner, C. David
2013-09-01
This report describes the theoretical background on modeling electron transport in the presence of electric and magnetic fields by incorporating the effects of the Lorentz force on electron motion into the Boltzmann transport equation. Electromagnetic fields alter the electron energy and trajectory continuously, and these effects can be characterized mathematically by differential operators in terms of electron energy and direction. Numerical solution techniques, based on the discrete-ordinates and finite-element methods, are developed and implemented in an existing radiation transport code, SCEPTRE.
Dealing with Multiple Solutions in Structural Vector Autoregressive Models.
Beltz, Adriene M; Molenaar, Peter C M
2016-01-01
Structural vector autoregressive models (VARs) hold great potential for psychological science, particularly for time series data analysis. They capture the magnitude, direction of influence, and temporal (lagged and contemporaneous) nature of relations among variables. Unified structural equation modeling (uSEM) is an optimal structural VAR instantiation, according to large-scale simulation studies, and it is implemented within an SEM framework. However, little is known about the uniqueness of uSEM results. Thus, the goal of this study was to investigate whether multiple solutions result from uSEM analysis and, if so, to demonstrate ways to select an optimal solution. This was accomplished with two simulated data sets, an empirical data set concerning children's dyadic play, and modifications to the group iterative multiple model estimation (GIMME) program, which implements uSEMs with group- and individual-level relations in a data-driven manner. Results revealed multiple solutions when there were large contemporaneous relations among variables. Results also verified several ways to select the correct solution when the complete solution set was generated, such as the use of cross-validation, maximum standardized residuals, and information criteria. This work has immediate and direct implications for the analysis of time series data and for the inferences drawn from those data concerning human behavior.
Institute of Scientific and Technical Information of China (English)
M. R. Setare; O. Hatami
2008-01-01
Based on the shape invariance property we obtain exact solutions of the Dirac equation for an electron moving in the presence of a certain varying magnetic field, then we also show its non-relativistic limit.
A Model for Teaching Electronic Commerce Students
Directory of Open Access Journals (Sweden)
Howard C. Woodard
2002-10-01
Full Text Available The teaching of information technology in an ever-changing world at universities presents a challenge. Are courses taught as concepts, while ignoring hands-on courses, leaving the hands-on classes to the technical colleges or trade schools? Does this produce the best employees for industry or give students the knowledge and skills necessary to function in a high-tech world? At GeorgiaCollege & StateUniversity (GC&SU a model was developed that combines both concepts and practical hands-on skill to meet this challenge. Using this model, a program was developed that consists of classroom lecture of concepts as well as practical hands-on exercises for mastering the knowledge and developing the skills necessary to succeed in the high-tech world of electronic commerce. The students become productive day one of a new job assignment. This solves the problem of students having the "book knowledge" but not knowing how to apply what has been learned.
Exact Solutions for Models of Cultural Transmission and Network Rewiring
Evans, T S
2006-01-01
We look at the evolution through rewiring of the degree distribution of a network so the number edges is constant. This is exactly equivalent to the evolution of probability distributions in models of cultural transmission with drift and innovation, or models of homogeneity in genes in the presence of mutation. We show that the mean field equations in the literature are incomplete and provide the full equations. We then give an exact solution for both their long time solution and for their approach to equilibrium. Numerical results show these are excellent approximations and confirm the characteristic simple inverse power law distributions with a large scale cutoff under certain conditions. The alternative is that we reach a completely homogeneous solution. We consider how such processes may arise in practice, using a recent Minority Game study as an example.
Numerical Comparison of Solutions of Kinetic Model Equations
Directory of Open Access Journals (Sweden)
A. A. Frolova
2015-01-01
Full Text Available The collision integral approximation by different model equations has created a whole new trend in the theory of rarefied gas. One widely used model is the Shakhov model (S-model obtained by expansion of inverse collisions integral in a series of Hermite polynomials up to the third order. Using the same expansion with another value of free parameters leads to a linearized ellipsoidal statistical model (ESL.Both model equations (S and ESL have the same properties, as they give the correct relaxation of non-equilibrium stress tensor components and heat flux vector, the correct Prandtl number at the transition to the hydrodynamic regime and do not guarantee the positivity of the distribution function.The article presents numerical comparison of solutions of Shakhov equation, ESL- model and full Boltzmann equation in the four Riemann problems for molecules of hard spheres.We have considered the expansion of two gas flows, contact discontinuity, the problem of the gas counter-flows and the problem of the shock wave structure. For the numerical solution of the kinetic equations the method of discrete ordinates is used.The comparison shows that solution has a weak sensitivity to the form of collision operator in the problem of expansions of two gas flows and results obtained by the model and the kinetic Boltzmann equations coincide.In the problem of the contact discontinuity the solution of model equations differs from full kinetic solutions at the point of the initial discontinuity. The non-equilibrium stress tensor has the maximum errors, the error of the heat flux is much smaller, and the ESL - model gives the exact value of the extremum of heat flux.In the problems of gas counter-flows and shock wave structure the model equations give significant distortion profiles of heat flux and non-equilibrium stress tensor components in front of the shock waves. This behavior is due to fact that in the models under consideration there is no dependency of the
Theory and modeling of electron fishbones
Vlad, G.; Fusco, V.; Briguglio, S.; Fogaccia, G.; Zonca, F.; Wang, X.
2016-10-01
Internal kink instabilities exhibiting fishbone like behavior have been observed in a variety of experiments where a high energy electron population, generated by strong auxiliary heating and/or current drive systems, was present. After briefly reviewing the experimental evidences of energetic electrons driven fishbones, and the main results of linear and nonlinear theory of electron fishbones, the results of global, self-consistent, nonlinear hybrid MHD-Gyrokinetic simulations will be presented. To this purpose, the extended/hybrid MHD-Gyrokinetic code XHMGC will be used. Linear dynamics analysis will enlighten the effect of considering kinetic thermal ion compressibility and diamagnetic response, and kinetic thermal electrons compressibility, in addition to the energetic electron contribution. Nonlinear saturation and energetic electron transport will also be addressed, making extensive use of Hamiltonian mapping techniques, discussing both centrally peaked and off-axis peaked energetic electron profiles. It will be shown that centrally peaked energetic electron profiles are characterized by resonant excitation and nonlinear response of deeply trapped energetic electrons. On the other side, off-axis peaked energetic electron profiles are characterized by resonant excitation and nonlinear response of barely circulating energetic electrons which experience toroidal precession reversal of their motion.
River network solution for a distributed hydrological model and applications
Jha, Raghunath; Herath, Srikantha; Musiake, Katumi
2000-02-01
A simultaneous solution for one-dimensional unsteady flow routing for a network of rivers has been developed, which can be used either with a complete distributed hydrological model, a simple rainfall-runoff model or as a stand alone river routing model. Either dynamic or kinematic solution schemes can be selected to simulate the river flows. The river network is either generated from the Digital Elevation Model (DEM) or directly input to the model. The model can handle any number of upstream channels and computational points. A sparse matrix solution algorithm is used to solve the 2N×2N matrix resulting from N nodes in the network. A submodule generates the initial water depth and discharge at each computational point from equilibrium discharge in the absence of observed initial conditions. The model is applied in three sub-catchments of the Chao Phraya river basin, Thailand, considering three different conditions. The simulated results show good agreement with observed discharges and provide insight to water level fluctuations, especially where tributaries join the main channel.
ADVAN-style analytical solutions for common pharmacokinetic models.
Abuhelwa, Ahmad Y; Foster, David J R; Upton, Richard N
2015-01-01
The analytical solutions to compartmental pharmacokinetic models are well known, but have not been presented in a form that easily allows for complex dosing regimen and changes in covariate/parameter values that may occur at discrete times within and/or between dosing intervals. Laplace transforms were used to derive ADVAN-style analytical solutions for 1, 2, and 3 compartment pharmacokinetic linear models of intravenous and first-order absorption drug administration. The equations calculate the change in drug amounts in each compartment of the model over a time interval (t; t = t2 - t1) accounting for any dose or covariate events acting in the time interval. The equations were coded in the R language and used to simulate the time-course of drug amounts in each compartment of the systems. The equations were validated against commercial software [NONMEM (Beal, Sheiner, Boeckmann, & Bauer, 2009)] output to assess their capability to handle both complex dosage regimens and the effect of changes in covariate/parameter values that may occur at discrete times within or between dosing intervals. For all tested pharmacokinetic models, the time-course of drug amounts using the ADVAN-style analytical solutions were identical to NONMEM outputs to at least four significant figures, confirming the validity of the presented equations. To our knowledge, this paper presents the ADVAN-style equations for common pharmacokinetic models in the literature for the first time. The presented ADVAN-style equations overcome obstacles to implementing the classical analytical solutions in software, and have speed advantages over solutions using differential equation solvers. The equations presented in this paper fill a gap in the pharmacokinetic literature, and it is expected that these equations will facilitate the investigation of useful open-source software for modelling pharmacokinetic data. Copyright © 2015 Elsevier Inc. All rights reserved.
Georgiadou, Dimitra G; Vasilopoulou, Maria; Palilis, Leonidas C; Petsalakis, Ioannis D; Theodorakopoulos, Giannoula; Constantoudis, Vassilios; Kennou, Stella; Karantonis, Antonis; Dimotikali, Dimitra; Argitis, Panagiotis
2013-12-11
Herein we introduce the all-organic triphenylsulfonium (TPS) salts cathode interfacial layers (CILs), deposited from their methanolic solution, as a new simple strategy for circumventing the use of unstable low work function metals and obtaining charge balance and high electroluminescence efficiency in polymer light-emitting diodes (PLEDs). In particular, we show that the incorporation of TPS-triflate or TPS-nonaflate at the polymer/Al interface improved substantially the luminous efficiency of the device (from 2.4 to 7.9 cd/A) and reduced the turn-on and operating voltage, whereas an up to 4-fold increase in brightness (∼11 250 cd/m(2) for TPS-triflate and ∼14 682 cd/m(2) for TPS-nonaflate compared to ∼3221 cd/m(2) for the reference device) was observed in poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(1,4-benzo-2,1',3-thiadiazole)] (F8BT)-based PLEDs. This was mainly attributed to the favorable decrease of the electron injection barrier, as derived from the open-circuit voltage (Voc) measurements, which was also assisted by the conduction of electrons through the triphenylsulfonium salt sites. Density functional theory calculations indicated that the total energy of the anionic (reduced) form of the salt, that is, upon placing an electron to its lowest unoccupied molecular orbital, is lower than its neutral state, rendering the TPS-salts stable upon electron transfer in the solid state. Finally, the morphology optimization of the TPS-salt interlayer through controlling the processing parameters was found to be critical for achieving efficient electron injection and transport at the respective interfaces.
Approximate Solutions of Interactive Dynamic Influence Diagrams Using Model Clustering
DEFF Research Database (Denmark)
Zeng, Yifeng; Doshi, Prashant; Qiongyu, Cheng
2007-01-01
Interactive dynamic influence diagrams (I-DIDs) offer a transparent and semantically clear representation for the sequential decision-making problem over multiple time steps in the presence of other interacting agents. Solving I-DIDs exactly involves knowing the solutions of possible models...
Optimal Model and Solution of Railway Hub Shift Working Plan
Institute of Scientific and Technical Information of China (English)
He Shiwei; Zhu Songnian; Lin Boliang
1996-01-01
Aiming at decreasing the hub transportation costs, a railway hub shift working plan in terms of multicommodity network flow model is set up for considering the coordination of freight working, train working and locomotive working plans. The solution and the calculating results are also introduced.
Foam for Enhanced Oil Recovery: Modeling and Analytical Solutions
Ashoori, E.
2012-01-01
Foam increases sweep in miscible- and immiscible-gas enhanced oil recovery by decreasing the mobility of gas enormously. This thesis is concerned with the simulations and analytical solutions for foam flow for the purpose of modeling foam EOR in a reservoir. For the ultimate goal of upscaling our mo
Modeling the Rheology of Polymer Melts and Solutions
Larson, R. G.; Desai, Priyanka S.
2015-01-01
We review constitutive modeling of solutions and melts of linear polymers, focusing on changes in rheological behavior in shear and extensional flow as the concentration increases from unentangled dilute, to entangled, to dense melt. The rheological changes are captured by constitutive equations, prototypes of which are the FENE-P model for unentangled solutions and the DEMG model for entangled solutions and melts. From these equations, and supporting experimental data, for dilute solutions, the extensional viscosity increases with the strain rate from the low-strain rate to the high-strain rate asymptote, but in the densely entangled state, the high-strain rate viscosity is lower than the low-shear rate value, especially when orientation-dependent friction is accounted for. In shearing flow, shear thinning increases dramatically as the entanglement density increases, which can eventually lead to a shear-banding inhomogeneity. Recent improvements in constitutive modeling are paving the way for robust and accurate numerical simulations of polymer fluid mechanics and industrial processing of polymers.
Approximate Solutions of Interactive Dynamic Influence Diagrams Using Model Clustering
DEFF Research Database (Denmark)
Zeng, Yifeng; Doshi, Prashant; Qiongyu, Cheng
2007-01-01
Interactive dynamic influence diagrams (I-DIDs) offer a transparent and semantically clear representation for the sequential decision-making problem over multiple time steps in the presence of other interacting agents. Solving I-DIDs exactly involves knowing the solutions of possible models of th....... We discuss the error bound of the approximation technique and demonstrate its empirical performance....
Foam for Enhanced Oil Recovery: Modeling and Analytical Solutions
Ashoori, E.
2012-01-01
Foam increases sweep in miscible- and immiscible-gas enhanced oil recovery by decreasing the mobility of gas enormously. This thesis is concerned with the simulations and analytical solutions for foam flow for the purpose of modeling foam EOR in a reservoir. For the ultimate goal of upscaling our mo
Numerical solution of dynamic equilibrium models under Poisson uncertainty
DEFF Research Database (Denmark)
Posch, Olaf; Trimborn, Timo
2013-01-01
of the retarded type. We apply the Waveform Relaxation algorithm, i.e., we provide a guess of the policy function and solve the resulting system of (deterministic) ordinary differential equations by standard techniques. For parametric restrictions, analytical solutions to the stochastic growth model and a novel...
Orbifolds and Exact Solutions of Strongly-Coupled Matrix Models
Cordova, Clay; Popolitov, Alexandr; Shakirov, Shamil
2016-01-01
We find an exact solution to strongly-coupled matrix models with a single-trace monomial potential. Our solution yields closed form expressions for the partition function as well as averages of Schur functions. The results are fully factorized into a product of terms linear in the rank of the matrix and the parameters of the model. We extend our formulas to include both logarthmic and finite-difference deformations, thereby generalizing the celebrated Selberg and Kadell integrals. We conjecture a formula for correlators of two Schur functions in these models, and explain how our results follow from a general orbifold-like procedure that can be applied to any one-matrix model with a single-trace potential.
Novel solutions for a model of wound healing angiogenesis
Harley, K.; van Heijster, P.; Marangell, R.; Pettet, G. J.; Wechselberger, M.
2014-12-01
We prove the existence of novel, shock-fronted travelling wave solutions to a model of wound healing angiogenesis studied in Pettet et al (2000 IMA J. Math. App. Med. 17 395-413) assuming two conjectures hold. In the previous work, the authors showed that for certain parameter values, a heteroclinic orbit in the phase plane representing a smooth travelling wave solution exists. However, upon varying one of the parameters, the heteroclinic orbit was destroyed, or rather cut-off, by a wall of singularities in the phase plane. As a result, they concluded that under this parameter regime no travelling wave solutions existed. Using techniques from geometric singular perturbation theory and canard theory, we show that a travelling wave solution actually still exists for this parameter regime. We construct a heteroclinic orbit passing through the wall of singularities via a folded saddle canard point onto a repelling slow manifold. The orbit leaves this manifold via the fast dynamics and lands on the attracting slow manifold, finally connecting to its end state. This new travelling wave is no longer smooth but exhibits a sharp front or shock. Finally, we identify regions in parameter space where we expect that similar solutions exist. Moreover, we discuss the possibility of more exotic solutions.
Energy Technology Data Exchange (ETDEWEB)
Hirano, Kazumi; Kinoshita, Takaaki [Laboratory of Cell Biology, Department of Bioinformatics, Faculty of Engineering, Soka University, 1-236 Tangi-machi, Hachioji, Tokyo 192-8577 (Japan); Uemura, Takeshi [Department of Molecular Neurobiology and Pharmacology, Graduate School of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Department of Molecular and Cellular Physiology, Shinshu University School of Medicine, 3-1-1 Asahi, Matsumoto, Nagano 390-8621 (Japan); Motohashi, Hozumi [Department of Gene Expression Regulation, Institute of Development, Aging and Cancer, Tohoku University, 4-1 Seiryo-cho, Aoba-ku, Sendai 980-8575 (Japan); Watanabe, Yohei; Ebihara, Tatsuhiko [Biomedical Research Institute, National Institute of Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba 305-8566 (Japan); Nishiyama, Hidetoshi [JEOL Ltd., 1-2 Musashino 3-chome, Akishima, Tokyo 196-8558 (Japan); Sato, Mari [Biomedical Research Institute, National Institute of Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba 305-8566 (Japan); Suga, Mitsuo [JEOL Ltd., 1-2 Musashino 3-chome, Akishima, Tokyo 196-8558 (Japan); Maruyama, Yuusuke; Tsuji, Noriko M. [Biomedical Research Institute, National Institute of Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba 305-8566 (Japan); Yamamoto, Masayuki [Department of Medical Biochemistry, Tohoku University Graduate School of Medicine, 2-1 Seiryo-cho, Aoba-ku, Sendai 980-8575 (Japan); Nishihara, Shoko, E-mail: shoko@soka.ac.jp [Laboratory of Cell Biology, Department of Bioinformatics, Faculty of Engineering, Soka University, 1-236 Tangi-machi, Hachioji, Tokyo 192-8577 (Japan); Sato, Chikara, E-mail: ti-sato@aist.go.jp [Biomedical Research Institute, National Institute of Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba 305-8566 (Japan)
2014-08-01
Correlative light-electron microscopy of cells in a natural environment of aqueous liquid facilitates high-throughput observation of protein complex formation. ASEM allows the inverted SEM to observe the wet sample from below, while an optical microscope observes it from above quasi-simultaneously. The disposable ASEM dish with a silicon nitride (SiN) film window can be coated variously to realize the primary-culture of substrate-sensitive cells in a few milliliters of culture medium in a stable incubator environment. Neuron differentiation, neural networking, proplatelet-formation and phagocytosis were captured by optical or fluorescence microscopy, and imaged at high resolution by gold-labeled immuno-ASEM with/without metal staining. Fas expression on the cell surface was visualized, correlated to the spatial distribution of F-actin. Axonal partitioning was studied using primary-culture neurons, and presynaptic induction by GluRδ2-N-terminus-linked fluorescent magnetic beads was correlated to the presynaptic-marker Bassoon. Further, megakaryocytes secreting proplatelets were captured, and P-selectins with adherence activity were localized to some of the granules present by immuno-ASEM. The phagocytosis of lactic acid bacteria by dendritic cells was also imaged. Based on these studies, ASEM correlative microscopy promises to allow the study of various mesoscopic-scale dynamics in the near future. - Highlights: • In situ correlative light electron microscopy of samples in open solution by ASEM. • Primary cultures for in-solution CLEM by developing SiN-film coating methods • First visualization of fluorescent magnetic beads in aqueous solution by CLEM. • Presynaptic induction of neurons by GluRδ2-N-terminus-coated beads studied by CLEM. • Axonal partitioning, bacterial phagocytosis, platelet formation imaged by CLEM.
Similarity solutions for systems arising from an Aedes aegypti model
Freire, Igor Leite; Torrisi, Mariano
2014-04-01
In a recent paper a new model for the Aedes aegypti mosquito dispersal dynamics was proposed and its Lie point symmetries were investigated. According to the carried group classification, the maximal symmetry Lie algebra of the nonlinear cases is reached whenever the advection term vanishes. In this work we analyze the family of systems obtained when the wind effects on the proposed model are neglected. Wide new classes of solutions to the systems under consideration are obtained.
Indian Academy of Sciences (India)
S S Ghosh; A Sen; G S Lakhina
2000-11-01
The nonlinear evolution of an electron acoustic wave is shown to obey the Davey–Stewartson I equation which admits so called dromion solutions. The importance of these two dimensional localized solutions for recent satellite observations of wave structures in the day side polar cap regions is discussed and the parameter regimes for their existence is delineated.
Water's structure around hydrophobic solutes and the iceberg model.
Galamba, N
2013-02-21
The structure of water in the hydration shells of small hydrophobic solutes was investigated through molecular dynamics. The results show that a subset of water molecules in the first hydration shell of a nonpolar solute have a significantly enhanced tetrahedrality and a slightly larger number of hydrogen bonds, relative to the molecules in water at room temperature, consistent with the experimentally observed negative excess entropy and increased heat capacity of hydrophobic solutions at room temperature. This ordering results from the rearrangement of a small number of water molecules near the nonpolar solutes that occupy one to two vertices of the enhanced water tetrahedra. Although this structuring is not nearly like that often associated with a literal interpretation of the term "iceberg" in the Frank and Evans iceberg model, it does support a moderate interpretation of this model. Thus, the tetrahedral orientational order of this ensemble of water molecules is comparable to that of liquid water at ~10 °C, although not accompanied by the small contraction of the O-O distance observed in cold water. Further, we show that the structural changes of water in the vicinity of small nonpolar solutes cannot be inferred from the water radial distribution functions, explaining why this increased ordering is not observed through neutron diffraction experiments. The present results restore a molecular view where the slower translational and reorientational dynamics of water near hydrophobic groups has a structural equivalent resembling water at low temperatures.
Exact Solution of a Drop-Push Model for Percolation
Majumdar, Satya N.; Dean, David S.
2002-08-01
Motivated by a computer science algorithm known as ``linear probing with hashing,'' we study a new type of percolation model whose basic features include a sequential ``dropping'' of particles on a substrate followed by their transport via a ``pushing'' mechanism. Our exact solution in one dimension shows that, unlike the ordinary random percolation model, the drop-push model has nontrivial spatial correlations generated by the dynamics itself. The critical exponents in the drop-push model are also different from those of the ordinary percolation. The relevance of our results to computer science is pointed out.
Two state electron model for geminate recombination of electron-ion pairs in liquid isooctane
Energy Technology Data Exchange (ETDEWEB)
Lukin, L.V., E-mail: lukin@binep.ac.ru [Institute of Energy Problems of Chemical Physics (Branch), Russian Academy of Sciences, Chernogolovka, P.O. Box 56, Moscow oblast 142432 (Russian Federation); Yakovlev, B.S. [Institute of Energy Problems of Chemical Physics (Branch), Russian Academy of Sciences, Chernogolovka, P.O. Box 56, Moscow oblast 142432 (Russian Federation)
2011-04-28
Graphical abstract: M + n . h{nu} {yields} mobile electron {yields} trapped electron {yields} free charges. Research highlights: {yields} Electrons produced by ionization of liquid alkanes are trapped near positive ions. {yields} The recombination kinetics was expressed in terms of a trapped electron life time. {yields} Transient absorption after the ionizing pulse was analyzed for liquid isooctane. {yields} The life time of trapped electrons was found. - Abstract: Recombination kinetics of geminate electron-ion pairs is considered in the framework of the two state model for electron transport in liquid hydrocarbons. It is shown that the model well reproduces recent experimental data on the subpicosecond geminate recombination obtained in liquid isooctane. The life time of electrons in a localized state in isooctane is estimated to lie in the range between 0.14 ps and 0.57 ps at room temperature.
Modeling Electronic Properties of Complex Oxides
Krishnaswamy, Karthik
Complex oxides are a class of materials that have recently emerged as potential candidates for electronic applications owing to their interesting electronic properties. The goal of this dissertation is to develop a fundamental understanding of these electronic properties using a combination of first-principles approaches based on density functional theory (DFT), and Schr odinger-Poisson (SP) simulation (Abstract shortened by ProQuest.
A note on solutions of an equation modelling arterial deformation
Energy Technology Data Exchange (ETDEWEB)
Gordoa, P.R. [Area de Matematica Aplicada, ESCET, Universidad Rey Juan Carlos, C/ Tulipan s/n, 28933 Mostoles, Madrid (Spain)]. E-mail: pilar.gordoa@urjc.es
2007-08-15
The derivation of exact solutions for a partial differential equation modelling arterial deformation in large arteries is considered. Amongst other results, we show that, for any values of the parameters appearing in the equation, solutions in terms of the first Painleve transcendent can be obtained. This is in spite of the non-integrability of the equation. We also establish a connection, via an approximation of the equation under study by the Korteweg-de Vries equation, with the second Painleve equation. Our results thus serve to further demonstrate the wide applicability and importance of the Painleve equations.
Modeling Corrosion Reactions of Steel in a Dilute Carbonate Solution
Eliyan, Faysal Fayez; Alfantazi, Akram
2016-02-01
This research models the corrosion reactions of a high-strength steel in an aerated, dilute, carbonate solution during a single-cycle voltammetry. Based on a previous study (Eliyan et al. in J Mater Eng Perform 24(6):1-8, 2015) and a literature survey, the corrosion reactions of the cathodic reduction, anodic dissolution, and passivation, as well as the interfacial interactions and the chemistry of the corrosion products are illustrated in schematics. The paper provides a visual guide on the corrosion reactions for steel in carbonate solutions based on the available mechanistic details that were reported and are still being investigated in literature.
Feature Solution in the Process of Parameterizing Port Model
Institute of Scientific and Technical Information of China (English)
彭禹; 郝志勇; 孙秀永; 刘东航; 付鲁华
2004-01-01
Aimed at attaining to an integrated and effective pattern to guide the port design process, this paper puts forward a new conception of feature solution, which is based on the parameterized feature modeling. With this solution, the overall pert pre-design process can be conducted in a virtual pattern. Moreover, to evaluate the advantages of the new design pattern, an application of port system has been involved in this paper; and in the process of application a computational fluid dynamic analysis is concerned. An ideal effect of cleanness,high efficiency and high precision has been achieved.
Exact Solution in Chaotic Inflation Model with Negative Potential
Institute of Scientific and Technical Information of China (English)
王文福
2003-01-01
New exact solution to the Einstein equations that describe the evolution of cosmological chaotic inflation model is derived. The inflation is driven by the evolution of scalar field with negative potential V( )=-Vo +1/2m2ψ2.This includes the solution which is exponential inflation for ψo ＞ψ＞ψf , and then develops smoothly towards the radiation-like evolution for ψ＜ψf. The spectral indices of the scalar density ns and the gravitational wave fluctuations ng are computed. The value of ns lies well inside the limits set by the cosmic background explorer satellite.
Molecular Thermodynamic Modeling of Fluctuation Solution Theory Properties
DEFF Research Database (Denmark)
O’Connell, John P.; Abildskov, Jens
2013-01-01
Fluctuation Solution Theory provides relationships between integrals of the molecular pair total and direct correlation functions and the pressure derivative of solution density, partial molar volumes, and composition derivatives of activity coefficients. For dense fluids, the integrals follow...... for densities and gas solubilities, including ionic liquids and complex mixtures such as coal liquids. The approach is especially useful in systems with strong nonidealities. This chapter describes successful application of such modeling to a wide variety of systems treated over several decades and suggests how...
Electron microscopy and theoretical modeling of cochleates.
Nagarsekar, Kalpa; Ashtikar, Mukul; Thamm, Jana; Steiniger, Frank; Schacher, Felix; Fahr, Alfred; May, Sylvio
2014-11-11
Cochleates are self-assembled cylindrical condensates that consist of large rolled-up lipid bilayer sheets and represent a novel platform for oral and systemic delivery of therapeutically active medicinal agents. With few preceding investigations, the physical basis of cochleate formation has remained largely unexplored. We address the structure and stability of cochleates in a combined experimental/theoretical approach. Employing different electron microscopy methods, we provide evidence for cochleates consisting of phosphatidylserine and calcium to be hollow tubelike structures with a well-defined constant lamellar repeat distance and statistically varying inner and outer radii. To rationalize the relation between inner and outer radii, we propose a theoretical model. Based on the minimization of a phenomenological free energy expression containing a bending, adhesion, and frustration contribution, we predict the optimal tube dimensions of a cochleate and estimate ratios of material constants for cochleates consisting of phosphatidylserines with varied hydrocarbon chain structures. Knowing and understanding these ratios will ultimately benefit the successful formulation of cochleates for drug delivery applications.
The secret to successful solute-transport modeling
Konikow, L.F.
2011-01-01
Modeling subsurface solute transport is difﬁcult—more so than modeling heads and ﬂows. The classical governing equation does not always adequately represent what we see at the ﬁeld scale. In such cases, commonly used numerical models are solving the wrong equation. Also, the transport equation is hyperbolic where advection is dominant, and parabolic where hydrodynamic dispersion is dominant. No single numerical method works well for all conditions, and for any given complex ﬁeld problem, where seepage velocity is highly variable, no one method will be optimal everywhere. Although we normally expect a numerically accurate solution to the governing groundwater-ﬂow equation, errors in concentrations from numerical dispersion and/or oscillations may be large in some cases. The accuracy and efﬁciency of the numerical solution to the solute-transport equation are more sensitive to the numerical method chosen than for typical groundwater-ﬂow problems. However, numerical errors can be kept within acceptable limits if sufﬁcient computational effort is expended. But impractically long
The “2T” ion-electron semi-analytic shock solution for code-comparison with xRAGE: A report for FY16
Energy Technology Data Exchange (ETDEWEB)
Ferguson, Jim Michael [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
2016-10-05
This report documents an effort to generate the semi-analytic "2T" ion-electron shock solution developed in the paper by Masser, Wohlbier, and Lowrie [1], and the initial attempts to understand how to use this solution as a code-verification tool for one of LANL's ASC codes, xRAGE. Most of the work so far has gone into generating the semi-analytic solution. Considerable effort will go into understanding how to write the xRAGE input deck that both matches the boundary conditions imposed by the solution, and also what physics models must be implemented within the semi-analytic solution itself to match the model assumptions inherit within xRAGE. Therefore, most of this report focuses on deriving the equations for the semi-analytic 1D-planar time-independent "2T" ion-electron shock solution, and is written in a style that is intended to provide clear guidance for anyone writing their own solver.
The “2T” ion-electron semi-analytic shock solution for code-comparison with xRAGE: A report for FY16
Energy Technology Data Exchange (ETDEWEB)
Ferguson, Jim Michael [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
2016-10-05
This report documents an effort to generate the semi-analytic "2T" ion-electron shock solution developed in the paper by Masser, Wohlbier, and Lowrie, and the initial attempts to understand how to use this solution as a code-verification tool for one of LANL's ASC codes, xRAGE. Most of the work so far has gone into generating the semi-analytic solution. Considerable effort will go into understanding how to write the xRAGE input deck that both matches the boundary conditions imposed by the solution, and also what physics models must be implemented within the semi-analytic solution itself to match the model assumptions inherit within xRAGE. Therefore, most of this report focuses on deriving the equations for the semi-analytic 1D-planar time-independent "2T" ion-electron shock solution, and is written in a style that is intended to provide clear guidance for anyone writing their own solver.
1976-12-01
The time dependent solution is presented for the dynamical behavior of the one dimensional electron boundary layer formed when X-rays knock photoelectrons out of a material surface. The X-ray flux is taken to be either linearly rising in time or constant in time . Two electron energy spectra are considered-exponential and linear-times-exponential. The electrons are assumed to have a cos theta
Assessment of Solution Uncertainties in Single-Column Modeling Frameworks.
Hack, James J.; Pedretti, John A.
2000-01-01
Single-column models (SCMs) have been extensively promoted in recent years as an effective means to develop and test physical parameterizations targeted for more complex three-dimensional climate models. Although there are some clear advantages associated with single-column modeling, there are also some significant disadvantages, including the absence of large-scale feedbacks. Basic limitations of an SCM framework can make it difficult to interpret solutions, and at times contribute to rather striking failures to identify even first-order sensitivities as they would be observed in a global climate simulation. This manuscript will focus on one of the basic experimental approaches currently exploited by the single-column modeling community, with an emphasis on establishing the inherent uncertainties in the numerical solutions. The analysis will employ the standard physics package from the NCAR CCM3 and will illustrate the nature of solution uncertainties that arise from nonlinearities in parameterized physics. The results of this study suggest the need to make use of an ensemble methodology when conducting single-column modeling investigations.
Thermal equilibrium solution to new model of bipolar hybrid quantum hydrodynamics
Di Michele, Federica; Mei, Ming; Rubino, Bruno; Sampalmieri, Rosella
2017-08-01
In this paper we study the hybrid quantum hydrodynamic model for nano-sized bipolar semiconductor devices in thermal equilibrium. By introducing a hybrid version of the Bhom potential, we derive a bipolar hybrid quantum hydrodynamic model, which is able to account for quantum effects in a localized region of the device for both electrons and holes. Coupled with Poisson equation for the electric potential, the steady-state system is regionally degenerate in its ellipticity, due to the quantum effect only in part of the device. This regional degeneracy of ellipticity makes the study more challenging. The main purpose of the paper is to investigate the existence and uniqueness of the weak solutions to this new type of equations. We first establish the uniform boundedness of the smooth solutions to the modified bipolar quantum hydrodynamic model by the variational method, then we use the compactness technique to prove the existence of weak solutions to the original hybrid system by taking hybrid limit. In particular, we account for two different kinds of hybrid behaviour. We perform the first hybrid limit when both electrons and holes behave quantum in a given region of the device, and the second one when only one carrier exhibits hybrid behaviour, whereas the other one is presented classically in the whole domain. The semi-classical limit results are also obtained. Finally, the theoretical results are tested numerically on a simple toy model.
Loyd, Jody; Gregory, Don; Gaskin, Jessica
2016-01-01
/Fourier series hybrid approach. The presentation will give background remarks about the MSFC mini Lunar SEM concept and electron optics modeling, followed by a description of the alternate field modeling techniques that were tried, along with their incorporation into a ray-trace simulation. Next, the validation of this simulation against commercially available software will be discussed using an example lens as a test case. Then, the efficacy of aberration assessment using direct ray-tracing will be demonstrated, using this same validation case. The discussion will include practical error checks of the field solution. Finally, the ray-trace assessment of the MSFC mini Lunar SEM concept will be shown and discussed. The authors believe this presentation will be of general interest to practitioners of modeling and simulation, as well as those with a general optics background. Because electron optics and photon optics share many basic concepts (e.g., lenses, images, aberrations, etc.), the appeal of this presentation need not be restricted to just those interested in charged particle optics.
Geometry Modeling of an Electronic Expansion Valve Head
Institute of Scientific and Technical Information of China (English)
张川; 马善伟; 陈江平; 陈芝久; 陈文勇; 王健
2004-01-01
This paper proposed that the flow characteristic of electronic expansion valve should be adapted to the evaporator superheat gain to refrigerant flow rate under different working conditions. Two native methods of geometry modeling of electronic expansion valve head were introduced. By analysis of them, some shortcoming was detected and a universal modeling method of electronic expansion valve head was put forward. Through this model, the flow characteristic of EEV and the influence factors can be investigated more deeply.
Mesoscale modeling of solute precipitation and radiation damage
Energy Technology Data Exchange (ETDEWEB)
Zhang, Yongfeng [Idaho National Lab. (INL), Idaho Falls, ID (United States); Schwen, Daniel [Idaho National Lab. (INL), Idaho Falls, ID (United States); Ke, Huibin [Idaho National Lab. (INL), Idaho Falls, ID (United States); Univ. of Wisconsin, Madison, WI (United States); Bai, Xianming [Idaho National Lab. (INL), Idaho Falls, ID (United States); Hales, Jason [Idaho National Lab. (INL), Idaho Falls, ID (United States)
2015-09-01
This report summarizes the low length scale effort during FY 2014 in developing mesoscale capabilities for microstructure evolution in reactor pressure vessels. During operation, reactor pressure vessels are subject to hardening and embrittlement caused by irradiation-induced defect accumulation and irradiation-enhanced solute precipitation. Both defect production and solute precipitation start from the atomic scale, and manifest their eventual effects as degradation in engineering-scale properties. To predict the property degradation, multiscale modeling and simulation are needed to deal with the microstructure evolution, and to link the microstructure feature to material properties. In this report, the development of mesoscale capabilities for defect accumulation and solute precipitation are summarized. Atomic-scale efforts that supply information for the mesoscale capabilities are also included.
Daicong solution effects on brain ultrastructure in a rat model of Alzheimer's disease
Institute of Scientific and Technical Information of China (English)
Qian Yue; Yuling Ding; Hongyan Wang; Shumei Zhao; Shengming Zhang; Hongjuan Wu; Yiguang Wang; Fengjie Li; Yuanyuan Yang; Juanjuan Liu
2008-01-01
BACKGROUND: Infusion of kainic acid into the basal nuclei induces neuronal excitotoxicity, degeneration, and necrosis, resulting in disturbed learning and memory functions.OBJECTIVE: To explore the effects of different doses of traditional Chinese medicine Daicong solution on brain ultrastructure in a rat model of Alzheimer's disease.DESIGN, TIME AND SETTING: The randomized, controlled, cellular morphology experiment was performed at the Shandong Provincial Key Laboratory of Molecular Immunology of Weifang Medical University, China from October 2006 to March 2007.MATERIALS: Fifty healthy, Sprague Dawley rats, aged 22-months, were used to establish rat models of Alzheimer's disease. The Morris water maze was prepared at the Pharmacometrics Key Laboratory of Weifang Medical University in Shandong Province of China. Traditional Chinese medicine Daicong solution (crude drug 1 g/mL), composed of radix ginseng, rehmannia dried rhizome, anemarrhenae and radix astragali, was produced by the Department of Pharmacy of Hospital Affiliated to Weifang Medical University. Kainic acid was provided by Professor Xiuyan Li from Weifang Medical University.METHODS: A total of 40 model rats were equally and randomly divided into four groups: dementia model, low-dose Daicong solution (5 g/kg/d), moderate-dose Daicong solution (10 g/kg/d), and high-dose Daicong solution (20 g/kg/d). An additional 10 healthy rats served as the normal control group. Rats in the dementia model and normal control groups received saline (10 mL/kg/d).MAIN OUTCOME MEASURES: Neural cell ultrastructure was observed utilizing electron microscopy after 1 month of respective treatments.RESULTS: Compared with the normal control group, electron density and the number of ribosomes were significantly reduced in neuronal cytoplasm, and many lipofuscin grains and vacuole-like changes were observed in mitochondria in the dementia model group. In addition, nuclear chromatin presented with different sizes of plaque
Electron Transport through Models for Small-World Nanomaterials
Solomon, Lazarus; Novotny, Mark
2008-03-01
We investigate the quantum transport of (spinless) electrons through simplified models related to small-world nanomaterials. We employ a tight-binding Hamiltonian, and obtain the transmission coefficient from a matrix solution of the associated time-independent Schrödinger Equation. The system studied corresponds to d=1 semi-infinite input and output leads, connected to a `blob' of N atoms. We first present exact results for N inter-connected atoms, a fully-connected graph. The exact solution, for any N, is given both for symmetric and non-symmetric connections between the `blob' and the input/output. We then present numerical results obtained by removing some of the connections within the N-site `blob', thereby approaching transport through a small-world nanomaterial [1-4]. [1] S. Caliskan, M.A. Novotny, and J.I. Cerd'a, J. Appl. Phys., 102, 013707 (2007). [2] M.A. Novotny et al., J. Appl. Phys., 97, 10B309 (2005). [3] M.A. Novotny and S.M. Wheeler, Braz. J. Physics 34, 395 (2004). [4] J. Yancey, M.A. Novotny, and S.R. Gwaltney, 2008 March Meeting presentation.
Pseudo almost periodic solutions for a Lasota-Wazewska model
Directory of Open Access Journals (Sweden)
Samira Rihani
2016-03-01
Full Text Available In this work, we consider a new model describing the survival of red blood cells in animals. Specifically, we study a class of Lasota-Wazewska equation with pseudo almost periodic varying environment and mixed delays. By using the Banach fixed point theorem and some inequality analysis, we find sufficient conditions for the existence, uniqueness and stability of solutions. We generalize some results known for one type of delay and for the Lasota-Wazewska model with almost periodic and periodic coefficients. An example illustrates the proposed model.
Data mining with SPSS modeler theory, exercises and solutions
Wendler, Tilo
2016-01-01
Introducing the IBM SPSS Modeler, this book guides readers through data mining processes and presents relevant statistical methods. There is a special focus on step-by-step tutorials and well-documented examples that help demystify complex mathematical algorithms and computer programs. The variety of exercises and solutions as well as an accompanying website with data sets and SPSS Modeler streams are particularly valuable. While intended for students, the simplicity of the Modeler makes the book useful for anyone wishing to learn about basic and more advanced data mining, and put this knowledge into practice.
Electron impact ionization of tungsten ions in a statistical model
Demura, A. V.; Kadomtsev, M. B.; Lisitsa, V. S.; Shurygin, V. A.
2015-01-01
The statistical model for calculations of the electron impact ionization cross sections of multielectron ions is developed for the first time. The model is based on the idea of collective excitations of atomic electrons with the local plasma frequency, while the Thomas-Fermi model is used for atomic electrons density distribution. The electron impact ionization cross sections and related ionization rates of tungsten ions from W+ up to W63+ are calculated and then compared with the vast collection of modern experimental and modeling results. The reasonable correspondence between experimental and theoretical data demonstrates the universal nature of statistical approach to the description of atomic processes in multielectron systems.
The electronic-commerce-oriented virtual merchandise model
Fang, Xiaocui; Lu, Dongming
2004-03-01
Electronic commerce has been the trend of commerce activities. Providing with Virtual Reality interface, electronic commerce has better expressing capacity and interaction means. But most of the applications of virtual reality technology in EC, 3D model is only the appearance description of merchandises. There is almost no information concerned with commerce information and interaction information. This resulted in disjunction of virtual model and commerce information. So we present Electronic Commerce oriented Virtual Merchandise Model (ECVMM), which combined a model with commerce information, interaction information and figure information of virtual merchandise. ECVMM with abundant information provides better support to information obtainment and communication in electronic commerce.
Two state electron model for geminate recombination of electron-ion pairs in liquid isooctane
Lukin, L. V.; Yakovlev, B. S.
2011-04-01
Recombination kinetics of geminate electron-ion pairs is considered in the framework of the two state model for electron transport in liquid hydrocarbons. It is shown that the model well reproduces recent experimental data on the subpicosecond geminate recombination obtained in liquid isooctane. The life time of electrons in a localized state in isooctane is estimated to lie in the range between 0.14 ps and 0.57 ps at room temperature.
Modeling of sodium acetate recovery from aqueous solutions by electrodialysis.
Fidaleo, Marcello; Moresi, Mauro
2005-09-05
The main engineering parameters (i.e., ion transport numbers in solution and electro-membranes; effective solute and water transport numbers; effective membrane surface area, membrane surface resistances, and limiting current intensity) affecting the recovery of sodium acetate from model solutions by electrodialysis (ED) were determined in accordance with a sequential experimental procedure. Such parameters allowed a satisfactory simulation of a few validation tests carried out under constant or step-wisely variable current intensity. The performance of this ED process was characterized in terms of a current efficiency (omega) of about 93% in the constant-current region, a water transport number (t(W)) of about 15, and a specific energy consumption (epsilon) increasing from 0.14 to 0.31 kWh/kg for a solute recovery yield of 95% as the current density (j) was increased from 112 to 337 A/m2. The specific resistance of the anion- or cation-exchange membranes were found to be three or two times greater than those measured in aqueous NaCl solutions and are to be used to design and/or optimize ED stacks involved in the downstream processing of acetic acid fermentation broths.
Energy Technology Data Exchange (ETDEWEB)
Berger, R. L., E-mail: berger5@llnl.gov; Cohen, B. I. [Lawrence Livermore National Laboratory, University of California, P.O. Box 808, Livermore, California 94551 (United States); Brunner, S., E-mail: stephan.brunner@epfl.ch [Centre de Recherches en Physique des Plasmas, Association Euratom-Confédération Suisse, Ecole Polytechnique Fédérale de Lausanne, CRPP-PPB, CH-1015 Lausanne (Switzerland); Banks, J. W. [Department of Mathematical Sciences, Rensselaer Polytechnic Institute, AE 301, 110 8th Street, Troy, New York 12180 (United States); Winjum, B. J. [Department of Electrical Engineering, University of California, Los Angeles, California 90095 (United States)
2015-05-15
Kinetic simulations of two-dimensional finite-amplitude electron plasma waves are performed in a one-wavelength long system. A systematic study of the most unstable linear sideband mode, in particular its growth rate γ and wavenumber k{sub y}, is carried out by scanning the amplitude and wavenumber of the initial wave. Simulation results are compared with numerical and analytical solutions to a two-dimensional nonlinear Schrödinger model [H. A. Rose and L. Yin, Phys. Plasmas 15, 042311 (2008)] and to the reduced model by Kruer et al. [Phys. Rev. Lett. 23, 838 (1969)] generalized to two dimensions.
Cook, Paul P
2016-01-01
We investigate two-parameter solutions of sigma-models on two dimensional symmetric spaces contained in E11. Embedding such sigma-model solutions in space-time gives solutions of M* and M'-theory where the metric depends on general travelling wave functions, as opposed to harmonic functions typical in general relativity, supergravity and M-theory. Weyl reflection allows such solutions to be mapped to M-theory solutions where the wave functions depend explicitly on extra coordinates contained in the fundamental representation of E11.
Teaching Behavioral Modeling and Simulation Techniques for Power Electronics Courses
Abramovitz, A.
2011-01-01
This paper suggests a pedagogical approach to teaching the subject of behavioral modeling of switch-mode power electronics systems through simulation by general-purpose electronic circuit simulators. The methodology is oriented toward electrical engineering (EE) students at the undergraduate level, enrolled in courses such as "Power Electronics,"…
Accountability Analysis of Electronic Commerce Protocols by Finite Automaton Model
Institute of Scientific and Technical Information of China (English)
Xie Xiao-yao; Zhang Huan-guo
2004-01-01
The accountability of electronic commerce protocols is an important aspect to insures security of electronic transaction. This paper proposes to use Finite Automaton (FA) model as a new kind of framework to analyze the trans action protocols in the application of electronic commerce.
Reduced M(atrix) theory models: ground state solutions
López, J L
2015-01-01
We propose a method to find exact ground state solutions to reduced models of the SU($N$) invariant matrix model arising from the quantization of the 11-dimensional supermembrane action in the light-cone gauge. We illustrate the method by applying it to lower dimensional toy models and for the SU(2) group. This approach could, in principle, be used to find ground state solutions to the complete 9-dimensional model and for any SU($N$) group. The Hamiltonian, the supercharges and the constraints related to the SU($2$) symmetry are built from operators that generate a multicomponent spinorial wave function. The procedure is based on representing the fermionic degrees of freedom by means of Dirac-like gamma matrices, as was already done in the first proposal of supersymmetric (SUSY) quantum cosmology. We exhibit a relation between these finite $N$ matrix theory ground state solutions and SUSY quantum cosmology wave functions giving a possible physical significance of the theory even for finite $N$.
Comparison between analytical and numerical solution of mathematical drying model
Shahari, N.; Rasmani, K.; Jamil, N.
2016-02-01
Drying is often related to the food industry as a process of shifting heat and mass inside food, which helps in preserving food. Previous research using a mass transfer equation showed that the results were mostly concerned with the comparison between the simulation model and the experimental data. In this paper, the finite difference method was used to solve a mass equation during drying using different kinds of boundary condition, which are equilibrium and convective boundary conditions. The results of these two models provide a comparison between the analytical and the numerical solution. The result shows a close match between the two solution curves. It is concluded that the two proposed models produce an accurate solution to describe the moisture distribution content during the drying process. This analysis indicates that we have confidence in the behaviour of moisture in the numerical simulation. This result demonstrated that a combined analytical and numerical approach prove that the system is behaving physically. Based on this assumption, the model of mass transfer was extended to include the temperature transfer, and the result shows a similar trend to those presented in the simpler case.
Akiel, R D; Stepanov, V; Takahashi, S
2016-06-21
Nanodiamond (ND) is an attractive class of nanomaterial for fluorescent labeling, magnetic sensing of biological molecules, and targeted drug delivery. Many of those applications require tethering of target biological molecules on the ND surface. Even though many approaches have been developed to attach macromolecules to the ND surface, it remains challenging to characterize dynamics of tethered molecule. Here, we show high-frequency electron paramagnetic resonance (HF EPR) spectroscopy of nitroxide-functionalized NDs. Nitroxide radical is a commonly used spin label to investigate dynamics of biological molecules. In the investigation, we developed a sample holder to overcome water absorption of HF microwave. Then, we demonstrated HF EPR spectroscopy of nitroxide-functionalized NDs in aqueous solution and showed clear spectral distinction of ND and nitroxide EPR signals. Moreover, through EPR spectral analysis, we investigate dynamics of nitroxide radicals on the ND surface. The demonstration sheds light on the use of HF EPR spectroscopy to investigate biological molecule-functionalized nanoparticles.
Wafer-scale solution-derived molecular gate dielectrics for low-voltage graphene electronics
Energy Technology Data Exchange (ETDEWEB)
Sangwan, Vinod K.; Jariwala, Deep; McMorrow, Julian J.; He, Jianting; Lauhon, Lincoln J. [Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208 (United States); Everaerts, Ken [Department of Chemistry, Northwestern University, Evanston, Illinois 60208 (United States); Grayson, Matthew [Department of Electrical Engineering and Computer Science, Northwestern University, Evanston, Illinois 60208 (United States); Marks, Tobin J., E-mail: t-marks@northwestern.edu, E-mail: m-hersam@northwestern.edu; Hersam, Mark C., E-mail: t-marks@northwestern.edu, E-mail: m-hersam@northwestern.edu [Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208 (United States); Department of Chemistry, Northwestern University, Evanston, Illinois 60208 (United States)
2014-02-24
Graphene field-effect transistors are integrated with solution-processed multilayer hybrid organic-inorganic self-assembled nanodielectrics (SANDs). The resulting devices exhibit low-operating voltage (2 V), negligible hysteresis, current saturation with intrinsic gain >1.0 in vacuum (pressure < 2 × 10{sup −5} Torr), and overall improved performance compared to control devices on conventional SiO{sub 2} gate dielectrics. Statistical analysis of the field-effect mobility and residual carrier concentration demonstrate high spatial uniformity of the dielectric interfacial properties and graphene transistor characteristics over full 3 in. wafers. This work thus establishes SANDs as an effective platform for large-area, high-performance graphene electronics.
Wafer-scale solution-derived molecular gate dielectrics for low-voltage graphene electronics
Sangwan, Vinod K.; Jariwala, Deep; Everaerts, Ken; McMorrow, Julian J.; He, Jianting; Grayson, Matthew; Lauhon, Lincoln J.; Marks, Tobin J.; Hersam, Mark C.
2014-02-01
Graphene field-effect transistors are integrated with solution-processed multilayer hybrid organic-inorganic self-assembled nanodielectrics (SANDs). The resulting devices exhibit low-operating voltage (2 V), negligible hysteresis, current saturation with intrinsic gain >1.0 in vacuum (pressure < 2 × 10-5 Torr), and overall improved performance compared to control devices on conventional SiO2 gate dielectrics. Statistical analysis of the field-effect mobility and residual carrier concentration demonstrate high spatial uniformity of the dielectric interfacial properties and graphene transistor characteristics over full 3 in. wafers. This work thus establishes SANDs as an effective platform for large-area, high-performance graphene electronics.
Security Attacks and Solutions in Electronic Health (E-health) Systems.
Zeadally, Sherali; Isaac, Jesús Téllez; Baig, Zubair
2016-12-01
For centuries, healthcare has been a basic service provided by many governments to their citizens. Over the past few decades, we have witnessed a significant transformation in the quality of healthcare services provided by healthcare organizations and professionals. Recent advances have led to the emergence of Electronic Health (E-health), largely made possible by the massive deployment and adoption of information and communication technologies (ICTs). However, cybercriminals and attackers are exploiting vulnerabilities associated primarily with ICTs, causing data breaches of patients' confidential digital health information records. Here, we review recent security attacks reported for E-healthcare and discuss the solutions proposed to mitigate them. We also identify security challenges that must be addressed by E-health system designers and implementers in the future, to respond to threats that could arise as E-health systems become integrated with technologies such as cloud computing, the Internet of Things, and smart cities.
Ustun, Yakup; Uzun, Ozgur; Er, Ozgur; Maden, Murat; Yalpı, Fatma; Canakci, Burhan Can
2013-01-01
The effects of three dissolving agents on the accuracy of an electronic apex locator- (EAL-) integrated endodontic handpiece during retreatment procedures were evaluated. The true lengths (TLs) of 56 extracted incisor teeth were determined visually. Twenty teeth were filled with gutta-percha and a resin-based sealer (group A), 20 with gutta-percha and a zinc oxide/eugenol-based sealer (group B), and 16 roots were used as the control group (group C). All roots were prepared to TL. Guttasolv, Resosolv, and Endosolv E were used as the dissolving solutions. Two evaluations of the handpiece were performed: the apical accuracy during the auto reverse function (ARL) and the apex locator function (EL) alone. The ARL function of the handpiece gave acceptable results. There were significant differences between the EL mode measurements and the TL (P < 0.05). In these comparisons, Tri Auto ZX EL mode measurements were significantly shorter than those of the TL. PMID:24379743
Monoenergetic electron parameters in a spheroid bubble model
Institute of Scientific and Technical Information of China (English)
H.Sattarian; Sh.Rahmatallahpur; T.Tohidi
2013-01-01
A reliable analytical expression for the potential of plasma waves with phase velocities near the speed of light is derived.The presented spheroid cavity model is more consistent than the previous spherical and ellipsoidal models and it explains the mono-energetic electron trajectory more accurately,especially at the relativistic region.The maximum energy of electrons is calculated and it is shown that the maximum energy of the spheroid model is less than that of the spherical model.The electron energy spectrum is also calculated and it is found that the energy distribution ratio of electrons △E/E for the spheroid model under the conditions reported here is half that of the spherical model and it is in good agreement with the experimental value in the same conditions.As a result,the quasi-mono-energetic electron output beam interacting with the laser plasma can be more appropriately described with this model.
Integrable cosmological models with non-minimal coupling and bounce solutions
Pozdeeva, Ekaterina
2016-01-01
We remind the way to obtain integrable models with non-minimally coupled scalar fields. We are interesting to models with bounce solutions and compare bounce solutions in two known integrable models. We show that only one model has a bounce solution that tends to a stable de Sitter solution.
Modeling Electron Transport in Vertical-SOI NMOSFET by Directly Solving BTE with FEA
Institute of Scientific and Technical Information of China (English)
TONG Jian-nong; ZOU Xue-cheng; SHEN Xu-bang
2004-01-01
A numerical schemes applicable to the direct solution of Boltzmann transport equation (BTE) in vertical-SOI NMOSFET are investigated by means of the finite element analysis (FEA).The solution gives the electron distribution function,electrostatic potential,carriers concentration,drift velocity,average energy and drain current by directly solving the BTE and the Poisson equation self-consistency.The result shows that the direct numerical solution of the BTE with the aid of FEA and vertical SOI NMOSFET is a promising approach for ultra short channel transistors modeling.
Solutions for a hyperbolic model of multi-phase flow
Directory of Open Access Journals (Sweden)
Amadori Debora
2013-07-01
Full Text Available We discuss a model for the flow of an inviscid fluid admitting liquid and vapor phases, as well as a mixture of them. The flow is modeled in one spatial dimension; the state variables are the specific volume, the velocity and the mass density fraction λ of vapor in the fluid. The equation governing the time evolution of λ contains a source term, which enables metastable states and drives the fluid towards stable pure phases. We first discuss, for the homogeneous system, the BV stability of Riemann solutions generated by large initial data and check the validity of several sufficient conditions that are known in the literature. Then, we review some recent results about the existence of solutions, which are globally defined in time, for λ close either to 0 or to 1 (corresponding to almost pure phases. These solutions possibly contain large shocks. Finally, in the relaxation limit, solutions are proved to satisfy a reduced system and the related entropy condition. On discute un modèle pour l’écoulement d’un fluide non visqueux admettant phases liquides et de vapeur, ainsi qu’un mélange d’entre eux. L’écoulement est modélisé dans une dimension spatiale ; les variables d’état sont le volume spécifique, la vitesse et la fraction de densité de masse λ de la vapeur dans le liquide. L’équation régissant l’évolution temporelle de λ contient un terme de source, ce qui permet des états métastables et conduit le fluide vers de phases stables pures. Nous discutons d’abord, pour le système homogène, la stabilité BV des solutions de Riemann générés par des grandes données initiales et vérifions la validité de plusieurs conditions suffisantes qui sont connues dans la littérature. Ensuite, nous passons en revue quelques résultats récents sur l’existence de solutions, qui sont definies pour tous les temps, pour λ soit près de 0 ou de 1 (correspondant à des phases presque pures. Ces solutions sont susceptibles
Modelling of electron beam absorption in complex geometries
Klassen, Alexander; Bauereiß, Andreas; Körner, Carolin
2014-02-01
Computational modelling of processes that involve highly energetic electrons like electron beam melting, welding, drilling or electron beam lithography, to name but a few, requires information about the attenuation of the electron beam as it passes through the sample. Depth-dose curves as a function of electron energy, target material as well as local surface obliquity have to be provided in situ during the calculation. The most efficient way to address this issue is by employing mathematical expressions. Therefore, we propose an electron beam model based on a set of semi-empirical equations available from different published literature and on theoretical considerations. Particular stress is thereby put on accuracy and the range of validity of the theoretical approach by comparison with experimental data. Finally, we apply our model to powder-bed based additive manufacturing. The numerical results demonstrate that electron beam absorption and depth of penetration have a strong influence on the quality of the fabricated product.
Heuristic model of chemically induced electron spin polarization in two dimensions
Adrian, Frank J.
2010-11-01
A heuristic model of chemically induced electron spin polarization (CIDEP) that breaks the polarization mechanism into its component steps, with each step governed by an appropriate solution of the diffusion equation, is extended from a three to a two-dimensional system. The required solution of the 2D diffusion equation is provided by a relatively simple analytic approximation to the usual infinite series solution. The model yields the polarization and its time development for weak to strong singlet-triplet mixing in the radical pairs, whereas previous models are limited to very weak or very strong mixing. Its results agree with a variational solution of an integral equation of Monchick and are encouraging for observation of CIDEP in dimensionally restricted systems. The method also may be applicable to other diffusion-controlled, spin-dependent chemistry in spatially restricted environments.
Implantable electronics: emerging design issues and an ultra light-weight security solution.
Narasimhan, Seetharam; Wang, Xinmu; Bhunia, Swarup
2010-01-01
Implantable systems that monitor biological signals require increasingly complex digital signal processing (DSP) electronics for real-time in-situ analysis and compression of the recorded signals. While it is well-known that such signal processing hardware needs to be implemented under tight area and power constraints, new design requirements emerge with their increasing complexity. Use of nanoscale technology shows tremendous benefits in implementing these advanced circuits due to dramatic improvement in integration density and power dissipation per operation. However, it also brings in new challenges such as reliability and large idle power (due to higher leakage current). Besides, programmability of the device as well as security of the recorded information are rapidly becoming major design considerations of such systems. In this paper, we analyze the emerging issues associated with the design of the DSP unit in an implantable system. Next, we propose a novel ultra light-weight solution to address the information security issue. Unlike the conventional information security approaches like data encryption, which come at large area and power overhead and hence are not amenable for resource-constrained implantable systems, we propose a multilevel key-based scrambling algorithm, which exploits the nature of the biological signal to effectively obfuscate it. Analysis of the proposed algorithm in the context of neural signal processing and its hardware implementation shows that we can achieve high level of security with ∼ 13X lower power and ∼ 5X lower area overhead than conventional cryptographic solutions.
VHDL Model of Electronic-Lock System
Directory of Open Access Journals (Sweden)
J. Noga
2000-04-01
Full Text Available The paper describes the design of an electronic-lock system which wascompleted as part of the Basic VHDL course in the Department of Controland Measurement Faculty of Electrical Engineering and Informatics,Technical University of Ostrava, Czech Republic in co-operation withthe Department if Electronic Engineering, University of Hull, GreatBritain in the frame of TEMPUS project no. S_JEP/09468-95.
Using Feature Modelling and Automations to Select among Cloud Solutions
Quinton, Clément; Duchien, Laurence; Heymans, patrick; Mouton, Stéphane; Charlier, Etienne
2012-01-01
International audience; Cloud computing is a major trend in distributed computing environments. Resources are accessed on demand by customers and are delivered as services by cloud providers in a pay-per-use model. Companies provide their applications as services and rely on cloud providers to provision, host and manage such applications on top of their infrastructure. However, the wide range of cloud solutions and the lack of knowledge in this domain is a real problem for companies when faci...
Solutions to Integration Model of Rural Information Resources
Institute of Scientific and Technical Information of China (English)
Xirong; GAO; Bo; TAO
2014-01-01
The integration of rural information resources is a key factor restricting rural informationization and effective operation of rural information services. To solve problems of separate rural information resources and departments acting willfully regardless of overall interest,this paper analyzed characteristics and distribution of rural information resources,built a basic framework for integration of rural information resources and a mathematic model of integration,and finally came up with specific solutions to integration of rural information resources.
Institute of Scientific and Technical Information of China (English)
Li Yeping
2008-01-01
A one-dimensional stationary nonisentropic hydrodynamic model for semicon-ductor devices with non-constant lattice temperature is studied. This model consists of the equations for the electron density, the electron current density and electron tempera-ture, coupled with the Poisson equation of the electrostatic potential in a bounded interval supplemented with proper boundary conditions. The existence and uniqueness of a strong subsonic steady-state solution with positive particle density and positive temperature is established. The proof is based on the fixed-point arguments, the Stampacchia truncation methods, and the basic energy estimates.
Sauvé, Geneviève; Fernando, Roshan
2015-09-17
Organic photovoltaics (OPVs) are promising candidates for providing a low cost, widespread energy source by converting sunlight into electricity. Solution-processable active layers have predominantly consisted of a conjugated polymer donor blended with a fullerene derivative as the acceptor. Although fullerene derivatives have been the acceptor of choice, they have drawbacks such as weak visible light absorption and poor energy tuning that limit overall efficiencies. This has recently fueled new research to explore alternative acceptors that would overcome those limitations. During this exploration, one question arises: what are the important design principles for developing nonfullerene acceptors? It is generally accepted that acceptors should have high electron affinity, electron mobility, and absorption coefficient in the visible and near-IR region of the spectra. In this Perspective, we argue that alternative molecular acceptors, when blended with a conjugated polymer donor, should also have large nonplanar structures to promote nanoscale phase separation, charge separation and charge transport in blend films. Additionally, new material design should address the low dielectric constant of organic semiconductors that have so far limited their widespread application.
Exact solutions for the spin tune for model storage rings
Mane, S R
2002-01-01
We present exact analytical expressions for the spin tune for arbitrary values of the orbital action for several storage ring models. The models we treat contain Siberian Snakes, the use of which is essential to preserve the polarization of beams in high-energy proton storage rings. Our solutions contain some novel features. We also prove a previously conjectured claim about the behavior of spin tuneshifts in rings with multiple Snakes. The conjecture is based on numerical simulations, but our proof is analytical, and also nonperturbative.
Exact solution of an evolutionary model without aging
Onody, Roberto N.; de Medeiros, Nazareno G. F.
1999-09-01
We introduce an age-structured asexual population model containing all the relevant features of evolutionary aging theories. Beneficial as well as deleterious mutations, heredity, and arbitrary fecundity are present and managed by natural selection. An exact solution without aging is found. We show that fertility is associated with generalized forms of the Fibonacci sequence, while mutations and natural selection are merged into an integral equation which is solved by Fourier series. Average survival probabilities and Malthusian growth exponents are calculated and indicate that the system may exhibit mutational meltdown. The relevance of the model in the context of fissile reproduction groups like many protozoa and coelenterates is discussed.
Molecular Thermodynamic Model for Polyelectrolyte Solutions with Added Salts
Institute of Scientific and Technical Information of China (English)
ZHANGBo; CAIJun; 等
2002-01-01
A molecular thermodynamic model of polyelectrolyte developed previously was extended to polyelectrolyte solutions with added salts.Thermodynamic properties,such as activity coefficients of polyelectrolytes or added salts and osmotic coefficients of solvent, of a number of aqueous mixtures of polyelectrolytes and salts are analyzed with the proposed model.Successful correlation is obtained in the range of moderate or higher polyion concentration.For the same sample,thermodynamic properties of polyelectrolytes with and without simple electrolytes can be predicted mutually using parameters from regression data.
Thermodynamic Models from Fluctuation Solution Theory Analysis of Molecular Simulations
DEFF Research Database (Denmark)
Christensen, Steen; Peters, Günther H.j.; Hansen, Flemming Yssing
2007-01-01
Fluctuation solution theory (FST) is employed to analyze results of molecular dynamics (MD) simulations of liquid mixtures. The objective is to generate parameters for macroscopic GE-models, here the modified Margules model. We present a strategy for choosing the number of parameters included......, Mol. Simul. 33 (4–5) (2007) 449–457.]. The new one has advantages for systems with data points at dilute conditions. Prediction of bubble point pressures using parameters from the two objective functions are compared with experimental data for the binary mixtures methyl acetate–n-pentane and methyl...
A kinetic model for runaway electrons in the ionosphere
Directory of Open Access Journals (Sweden)
G. Garcia
2006-09-01
Full Text Available Electrodynamic models and measurements with satellites and incoherent scatter radars predict large field aligned current densities on one side of the auroral arcs. Different authors and different kinds of studies (experimental or modeling agree that the current density can reach up to hundreds of µA/m^{2}. This large current density could be the cause of many phenomena such as tall red rays or triggering of unstable ion acoustic waves. In the present paper, we consider the issue of electrons moving through an ionospheric gas of positive ions and neutrals under the influence of a static electric field. We develop a kinetic model of collisions including electrons/electrons, electrons/ions and electrons/neutrals collisions. We use a Fokker-Planck approach to describe binary collisions between charged particles with a long-range interaction. We present the essential elements of this collision operator: the Langevin equation for electrons/ions and electrons/electrons collisions and the Monte-Carlo and null collision methods for electrons/neutrals collisions. A computational example is given illustrating the approach to equilibrium and the impact of the different terms (electrons/electrons and electrons/ions collisions on the one hand and electrons/neutrals collisions on the other hand. Then, a parallel electric field is applied in a new sample run. In this run, the electrons move in the z direction parallel to the electric field. The first results show that all the electron distribution functions are non-Maxwellian. Furthermore, runaway electrons can carry a significant part of the total current density, up to 20% of the total current density.
Energy Technology Data Exchange (ETDEWEB)
Sun, Liang [CAS Key Laboratory of Bio-based Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Shen, Wenfei [CAS Key Laboratory of Bio-based Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101 (China); Institute of Hybrid Materials, Laboratory of New Fiber Materials and Modern Textile—The Growing Base for State Key Laboratory, Qingdao University, Qingdao 266071 (China); Chen, Weichao [CAS Key Laboratory of Bio-based Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101 (China); Bao, Xichang, E-mail: baoxc@qibebt.ac.cn [CAS Key Laboratory of Bio-based Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101 (China); Wang, Ning; Dou, Xiaowei; Han, Liangliang; Wen, Shuguang [CAS Key Laboratory of Bio-based Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101 (China)
2014-12-31
Titanium oxide (TiO{sub X}) is an effective electron transport layer (ETL) in polymer solar cells (PSCs). We report efficient inverted PSCs with a simple solution-processed amorphous TiO{sub X} (s-TiO{sub X}) film as an ETL. The s-TiO{sub X} film with high light transmittance was prepared by spin-coating titanium (IV) isopropoxide isopropanol solution on indium tin oxide coated glass in inert and then placed in air under room temperature for 60 min. The introduction of s-TiO{sub X} ETL greatly improved the short circuit current density of the devices. PSCs based on poly(3-hexylthiophene):[6,6]-phenyl-C61-butyric acid methyl ester and poly(4,8-bis-alkyloxy-benzo[1,2-b:4,5-b′]dithiophene-alt-alkylcarbonyl -thieno[3,4-b]thiophene):[6,6]-phenyl- C71-butyric acid methyl ester using s-TiO{sub X} film as ETL shows high power conversion efficiency of 4.29% and 6.7% under the illumination of AM 1.5G, 100 mW/cm{sup 2}, which shows enhancements compared to the conventional PSCs with poly(styrenesulfonate)-doped poly(ethylenedioxythiophene) as anode buffer layer. In addition, the device exhibits good stability in a humid ambient atmosphere without capsulation. The results indicate that the annealing-free, simple solution processed s-TiO{sub X} film is an efficient ETL for high-performance PSCs. - Highlights: • High quality s-TiO{sub X} films were prepared by a simple, solution method without thermal treatment. • The s-TiO{sub X} films with high transmittance are very smooth. • The organic photovoltaic performance with s-TiO{sub X} film improved greatly and exhibited good stability. • The annealing-free, simple prepared s-TiO{sub X} film will be much compatible with flexible substrates.
Burinskii, Alexander
2016-01-01
It is known that gravitational and electromagnetic fields of an electron are described by the ultra-extreme Kerr-Newman (KN) black hole solution with extremely high spin/mass ratio. This solution is singular and has a topological defect, the Kerr singular ring, which may be regularized by introducing the solitonic source based on the Higgs mechanism of symmetry breaking. The source represents a domain wall bubble interpolating between the flat region inside the bubble and external KN solution. It was shown recently that the source represents a supersymmetric bag model, and its structure is unambiguously determined by Bogomolnyi equations. The Dirac equation is embedded inside the bag consistently with twistor structure of the Kerr geometry, and acquires the mass from the Yukawa coupling with Higgs field. The KN bag turns out to be flexible, and for parameters of an electron, it takes the form of very thin disk with a circular string placed along sharp boundary of the disk. Excitation of this string by a traveling wave creates a circulating singular pole, indicating that the bag-like source of KN solution unifies the dressed and point-like electron in a single bag-string-quark system.
Super-Exponential Solution for a Retrial Supermarket Model
Li, Quan-Lin; Wang, Yang
2011-01-01
In this paper, we provide a new and effective approach for studying super-exponential solution of a retrial supermarket model with Poisson arrivals, exponential service times and exponential retrial times and with two different probing-server numbers. We describe the retrial supermarket model as a system of differential equations by means of density-dependent jump Markov processes, and obtain an iterative algorithm for computing the fixed point of the system of differential equations. Based on the fixed point, we analyze the expected sojourn time that a tagged arriving customer spends in this system, and use numerical examples to indicate different influence of the two probing-server numbers on system performance including the fixed point and the expected sojourn time. Furthermore, we analyze exponential convergence of the current location of the retrial supermarket model to the fixed point, and apply the Kurtz Theorem to study density-dependent jump Markov process given in the retrial supermarket model, whic...
Some Exact Solutions of Magnetized viscous model in String Cosmology
Singh, C P
2012-01-01
In this paper we study anisotropic Bianchi-V universe with magnetic field and bulk viscous fluid in string cosmology. Exact solutions of the field equations are obtained by using the equation of state for a cloud of strings and a relationship between bulk viscous coefficient and expansion scalar. The bulk viscous coefficient is assumed to be inversely proportional to the expansion scalar. It is interesting to examine the effects of magnetized bulk viscous string model in early and late stages of the evolution of the universe. This paper investigates the different string models like geometrical(Nambu string), Takabayashi (p-string) and Reddy string models by taking certain physical conditions. The introduction of magnetic field or bulk viscosity or both results in rapid change in scale factors as well as in the classical potential. The presence of viscosity prevents the universe to be empty in its future evolution. The physical and geometrical aspects of each string model are discussed in detail.
Nonextensive local composition models in theories of solutions
Borges, Ernesto P
2012-01-01
Thermodynamic models present binary interaction parameters, based on the Boltzmann weight. Discrepancies from experimental data lead to empirically consider temperature dependence of the parameters, but these modifications keep unchanged the exponential nature of the equations. We replace the Boltzmann weight by the nonextensive Tsallis weight, and generalize three models for nonelectrolyte solutions that use the local composition hypothesis, namely Wilson's, NRTL, and UNIQUAC models. The proposed generalizations present a nonexponential dependence on the temperature, and relies on a theoretical basis of nonextensive statistical mechanics. The $q$-models present one extra binary parameter $q_{ij}$, that recover the original cases in the limit $q_{ij} \\to 1$. Comparison with experimental data is illustrated with two examples of the activity coefficient of ethanol, infinitely diluted in toluene, and in decane.
Model Order Reduction for Electronic Circuits:
DEFF Research Database (Denmark)
Hjorth, Poul G.; Shontz, Suzanne
Electronic circuits are ubiquitous; they are used in numerous industries including: the semiconductor, communication, robotics, auto, and music industries (among many others). As products become more and more complicated, their electronic circuits also grow in size and complexity. This increased...... the need for circuit simulators to evaluate potential designs before fabrication, as integrated circuit prototypes are expensive to build, and troubleshooting is diﬃcult. In this report, we focus on the simulation of printed circuit boards (PCB’s) and interconnects both of which are of great importance...
Detailed Modeling of Grounding Solutions for the ITER ICRF Antenna
Kyrytsya, V.; Dumortier, P.; Messiaen, A.; Louche, F.; Durodié, F.
2011-12-01
The excitation of non-TEM modes around the ITER ICRF antenna plug can considerably increase the level of RF voltages and currents on the ITER plug. First study of these modes and a solution to avoid them in the ITER ion cyclotron range of frequencies were reported in [1]. In this work a detailed analysis of electrical properties of the ITER ICRF antenna with the plug was studied for different grounding solutions with CST Microwave Studio® [2]. Conclusions of an earlier work [ 1 ] were confirmed on the detailed model of the antenna with the plug. Different grounding contacts (capacitive, galvanic and mixed capacitive-galvanic) as well as their distribution inside the plug gap were analyzed. It was shown that capacitive and mixed capacitive-galvanic grounding are less effective because they demand high values of the capacitance and are more sensitive to the frequency and antenna spectrum. In particular a galvanic grounding realized by the contacts put around the perimeter of the plug gap at lm behind the front face of the antenna is the most suitable solution from the electromagnetic point of view. An optimization of the layout and arrangement of the contacts in order to assess and optimize the current distribution on them is under way. Measurements on a scaled mock-up of the complete antenna and the plug are under way for modeling results confirmation.
ARE MODELS OF ANION HYDRATION OVERBOUND ? THE SOLVATION OF THE ELECTRON AND CHLORIDE ANION COMPARED
Sprik, M.
1991-01-01
By means of a fully polarizable model for the chloride ion-water interaction we show that the modelling of anion solvation suffers from a similar inconsistency as the current electron-solvent potentials. Either the bulk hydration enthalpies are correct with the first hydration shell overbound, or the potential is adapted to describe the local environment of the solute at the expense of a major loss of solvation enthalpy. It is argued that boundary effects in the simulation are at least partly...
Molecular modeling and multiscaling issues for electronic material applications
Iwamoto, Nancy; Yuen, Matthew; Fan, Haibo
Volume 1 : Molecular Modeling and Multiscaling Issues for Electronic Material Applications provides a snapshot on the progression of molecular modeling in the electronics industry and how molecular modeling is currently being used to understand material performance to solve relevant issues in this field. This book is intended to introduce the reader to the evolving role of molecular modeling, especially seen through the eyes of the IEEE community involved in material modeling for electronic applications. Part I presents the role that quantum mechanics can play in performance prediction, such as properties dependent upon electronic structure, but also shows examples how molecular models may be used in performance diagnostics, especially when chemistry is part of the performance issue. Part II gives examples of large-scale atomistic methods in material failure and shows several examples of transitioning between grain boundary simulations (on the atomistic level)and large-scale models including an example ...
El-Wakil, S A; El-Shewy, E K; Abd-El-Hamid, H M
2010-01-01
A theoretical investigation has been made of electron acoustic wave propagating in unmagnetized collisionless plasma consisting of a cold electron fluid and isothermal ions with two different temperatures obeying Boltzmann type distributions. Based on the pseudo-potential approach, large amplitude potential structures and the existence of Solitary waves are discussed. The reductive perturbation method has been employed to derive the Korteweg-de Vries (KdV) equation for small but finite amplitude electrostatic waves. An algebraic method with computerized symbolic computation, which greatly exceeds the applicability of the existing tanh, extended tanh methods in obtaining a series of exact solutions of the KdV equation, is used here. Numerical studies have been made using plasma parameters close to those values corresponding to Earth's plasma sheet boundary layer region reveals different solutions i.e., bell-shaped solitary pulses and singularity solutions at a finite point which called "blowup" solutions, Jaco...
Coarse grained modeling of transport properties in monoclonal antibody solution
Swan, James; Wang, Gang
Monoclonal antibodies and their derivatives represent the fastest growing segment of the bio pharmaceutical industry. For many applications such as novel cancer therapies, high concentration, sub-cutaneous injections of these protein solutions are desired. However, depending on the peptide sequence within the antibody, such high concentration formulations can be too viscous to inject via human derived force alone. Understanding how heterogenous charge distribution and hydrophobicity within the antibodies leads to high viscosities is crucial to their future application. In this talk, we explore a coarse grained computational model of therapeutically relevant monoclonal antibodies that accounts for electrostatic, dispersion and hydrodynamic interactions between suspended antibodies to predict assembly and transport properties in concentrated antibody solutions. We explain the high viscosities observed in many experimental studies of the same biologics.
Orbital Models and Electronic Structure Theory
DEFF Research Database (Denmark)
Linderberg, Jan
2012-01-01
This tribute to the work by Carl Johan Ballhausen focuses on the emergence of quantitative means for the study of the electronic properties of complexes and molecules. Development, refinement and application of the orbital picture elucidated electric and magnetic features of ranges of molecules...
Olsen, Seth
2012-02-09
We examine a four-electron, three-orbital complete active space self-consistent field (SA-CASSCF) and multistate multireference perturbation theory (MS-MRPT2) model of the electronic structure associated with the two lowest-lying electronic excitations of a series of cationic diarylmethanes related to Michler's Hydrol Blue. These dyes are of interest because of the sensitivity of their excited-state dynamics to environmental influence in biological and other condensed phases. We show that the model corresponds to an easily understandable physical approximation where the dye electronic structure is mapped onto the π-electron system of an allyl anion. We show that reported trends in solution-state absorbance bands and transition dipole moments associated with the first two electronic excitations can be described within reasonable accuracy by the model. We also show, for Michler's Hydrol Blue, that the four-electron, three-orbital model provides a more balanced description of the electronic difference densities associated with electronic excitation calculated with the full π-electron space than can be achieved with active space models intermediate between these limits. The valence excitation energies predicted by the model are not sensitive to the underlying basis set, so that considerable computational savings may be possible by using split-valence basis sets with a limited number of polarization functions. We conclude that the model meets the criteria for a "Pauling Point": a point where the cancellation of large errors leads to physically balanced model, and where further elaboration degrades, rather than improves, the quality of description. We advocate that this Pauling Point be exploited in condensed-phase dynamical models where the computational overhead associated with the electronic structure must kept to a minimum (for example, nonadiabatic dynamics simulations coupled to QM/MM environmental models).
Source of Kerr-Newman solution as supersymmetric bag model: 50 years of the problem
Burinskii, A.
The ultra extreme Kerr-Newman (KN) solution(a = J/m >> m) produces the gravitational and EM fields of the electron. It has a naked singular ring - a topological defect which may be regularized by a solitonic source forming the pseudo-vacuum bubble filled by Higgs condensate in a supersymmetric superconducting state. Structure and stability of this source is determined by Bogomolnyi equations as a BPS-saturated soliton. The Principal Null Congruences of the KN solution determine consistent embedding of the Dirac equation, which acquires the mass from the Higgs condensate inside the soliton, indicating that this soliton forms a bag model. Shape of this bag is unambiguously determined by BPS-bound. The bag turns out to be flexible and takes the form of a very thin disk, which is completed by a ring-string along its sharp boundary. The ring-string traveling waves generate extra deformations of the bag creating a circulating singular pole. Bag model of the KN source integrates the dressed and pointlike electron in a bag-string-quark system, which removes the conflict between gravity and the point-like electron of the Dirac theory.
Ellipsoidal head model for fetal magnetoencephalography: forward and inverse solutions
Energy Technology Data Exchange (ETDEWEB)
Gutierrez, David [Department of Bioengineering, University of Illinois at Chicago, 851 S. Morgan St (M/C 063), Chicago, IL 60607-7053 (United States); Nehorai, Arye [Department of Bioengineering, University of Illinois at Chicago, 851 S. Morgan St (M/C 063), Chicago, IL 60607-7053 (United States); Department of Electrical and Computer Engineering, University of Illinois at Chicago, 851 S. Morgan St, 1120 SEO (M/C 154), Chicago, IL 60607-7053 (United States); Preissl, Hubert [Department of Obstetrics and Gynecology, University of Arkansas for Medical Sciences, Little Rock, AR 72205 (United States); MEG-Center, University of Tuebingen, Tuebingen, 72206 (Germany)
2005-05-07
Fetal magnetoencephalography (fMEG) is a non-invasive technique where measurements of the magnetic field outside the maternal abdomen are used to infer the source location and signals of the fetus' neural activity. There are a number of aspects related to fMEG modelling that must be addressed, such as the conductor volume, fetal position and orientation, gestation period, etc. We propose a solution to the forward problem of fMEG based on an ellipsoidal head geometry. This model has the advantage of highlighting special characteristics of the field that are inherent to the anisotropy of the human head, such as the spread and orientation of the field in relationship with the localization and position of the fetal head. Our forward solution is presented in the form of a kernel matrix that facilitates the solution of the inverse problem through decoupling of the dipole localization parameters from the source signals. Then, we use this model and the maximum likelihood technique to solve the inverse problem assuming the availability of measurements from multiple trials. The applicability and performance of our methods are illustrated through numerical examples based on a real 151-channel SQUID fMEG measurement system (SARA). SARA is an MEG system especially designed for fetal assessment and is currently used for heart and brain studies. Finally, since our model requires knowledge of the best-fitting ellipsoid's centre location and semiaxes lengths, we propose a method for estimating these parameters through a least-squares fit on anatomical information obtained from three-dimensional ultrasound images.
Turi, László
2016-04-21
We evaluate the applicability of a hierarchy of quantum models in characterizing the binding energy of excess electrons to water clusters. In particular, we calculate the vertical detachment energy of an excess electron from water cluster anions with methods that include one-electron pseudopotential calculations, density functional theory(DFT) based calculations, and ab initio quantum chemistry using MP2 and eom-EA-CCSD levels of theory. The examined clusters range from the smallest cluster size (n = 2) up to nearly nanosize clusters with n = 1000 molecules. The examined cluster configurations are extracted from mixed quantum-classical molecular dynamics trajectories of cluster anions with n = 1000 water molecules using two different one-electron pseudopotenial models. We find that while MP2 calculations with large diffuse basis set provide a reasonable description for the hydrated electron system, DFT methods should be used with precaution and only after careful benchmarking. Strictly tested one-electron psudopotentials can still be considered as reasonable alternatives to DFT methods, especially in large systems. The results of quantum chemistry calculations performed on configurations, that represent possible excess electron binding motifs in the clusters, appear to be consistent with the results using a cavitystructure preferring one-electron pseudopotential for the hydrated electron, while they are in sharp disagreement with the structural predictions of a non-cavity model.
A new ONERA-CNES Slot Electron Model.
Sicart-Piet, A.; Boscher, D.; Lazaro, D.; Bourdarie, S.; G. Rolland
2013-01-01
A new model of electron flux in the Slot Region has been developed at ONERA. This model is based on several data sets, low altitudes data as POES or SAC-C measurements, but also data at higher altitudes as HEO1, HEO3, ICO and CRRES measurements. This model provides mean electron flux between L=2 and L=4 for energies between 0.1 MeV and 3 MeV. This model includes a confidence level which takes into account the dynamics of electron flux in the slot region.
REFLECTIONS ON THE TWO-STATE ELECTRON TRANSFER MODEL.
Energy Technology Data Exchange (ETDEWEB)
Brunschwig, B.S.
2000-01-12
There is general agreement that the two most important factors determining electron transfer rates in solution are the degree of electronic interaction between the donor and acceptor sites, and the changes in the nuclear configurations of the donor, acceptor, and surrounding medium that occur upon the gain or loss of an electron Ll-51. The electronic interaction of the sites will be very weak, and the electron transfer slow, when the sites are far apart or their interaction is symmetry or spin forbidden. Since electron motion is much faster than nuclear motion, energy conservation requires that, prior to the actual electron transfer, the nuclear configurations of the reactants and the surrounding medium adjust from their equilibrium values to a configuration (generally) intermediate between that of the reactants and products. In the case of electron transfer between , two metal complexes in a polar solvent, the nuclear configuration changes involve adjustments in the metal-ligand and intraligand bond lengths and angles, and changes in the orientations of the surrounding solvent molecules. In common with ordinary chemical reactions, an electron transfer reaction can then be described in terms of the motion of the system on an energy surface from the reactant equilibrium configuration (initial state) to the product equilibrium configuration (final state) via the activated complex (transition state) configuration.
Dai, Si-Min; Tian, Han-Rui; Zhang, Mei-Lin; Xing, Zhou; Wang, Lu-Yao; Wang, Xin; Wang, Tan; Deng, Lin-Long; Xie, Su-Yuan; Huang, Rong-Bin; Zheng, Lan-Sun
2017-01-01
Discovery of organic-inorganic hybrid perovskites ignites the dream of next-generation solar cells fabricated by low-cost solution processing. To date, fullerene derivative [6,6]-phenyl-C61- butyric acid methyl ester (PC61BM), is the most prevalently used electron transport layer for high efficiency p-i-n planar heterojunction perovskite solar cells. Compared with PC61BM, pristine fullerenes, such as C60 and C70, have shown superiority of higher electron mobility and much lower costs. Due to the poor solubility and strong tendency to crystallize for pristine fullerenes in solution process, it is still a challenge to deposit compact and continuous film of pristine fullerenes for p-i-n type perovskite solar cells by solution processing. Herein, solution processed pristine fullerenes (C60 and C70) were used as electron transport layers to replace PC61BM in perovskite solar cells with high performance and enhanced stability. Power conversion efficiency of 14.04% was obtained by using mixture of C60 and C70 as electron transport layer, which is comparable to that of PC61BM based device (13.74%). We demonstrated that the strong tendency of pristine fullerenes to crystallize during solvent removal can be largely mitigated by mixing different kinds of pristine fullerenes. These findings implicate pristine fullerenes as promising electron transport layers for high performance perovskite solar cells.
DEM Solutions Develops Answers to Modeling Lunar Dust and Regolith
Dunn, Carol Anne; Calle, Carlos; LaRoche, Richard D.
2010-01-01
With the proposed return to the Moon, scientists like NASA-KSC's Dr. Calle are concerned for a number of reasons. We will be staying longer on the planet's surface, future missions may include dust-raising activities, such as excavation and handling of lunar soil and rock, and we will be sending robotic instruments to do much of the work for us. Understanding more about the chemical and physical properties of lunar dust, how dust particles interact with each other and with equipment surfaces and the role of static electricity build-up on dust particles in the low-humidity lunar environment is imperative to the development of technologies for removing and preventing dust accumulation, and successfully handling lunar regolith. Dr. Calle is currently working on the problems of the electrostatic phenomena of granular and bulk materials as they apply to planetary surfaces, particularly to those of Mars and the Moon, and is heavily involved in developing instrumentation for future planetary missions. With this end in view, the NASA Kennedy Space Center's Innovative Partnerships Program Office partnered with OEM Solutions, Inc. OEM Solutions is a global leader in particle dynamics simulation software, providing custom solutions for use in tackling tough design and process problems related to bulk solids handling. Customers in industries such as pharmaceutical, chemical, mineral, and materials processing as well as oil and gas production, agricultural and construction, and geo-technical engineering use OEM Solutions' EDEM(TradeMark) software to improve the design and operation of their equipment while reducing development costs, time-to-market and operational risk. EDEM is the world's first general-purpose computer-aided engineering (CAE) tool to use state-of-the-art discrete element modeling technology for the simulation and analysis of particle handling and manufacturing operations. With EDEM you'can quickly and easily create a parameterized model of your granular solids
Analytic solution of Hubbell's model of local community dynamics
McKane, A; Sole, R; Kane, Alan Mc; Alonso, David; Sole, Ricard
2003-01-01
Recent theoretical approaches to community structure and dynamics reveal that many large-scale features of community structure (such as species-rank distributions and species-area relations) can be explained by a so-called neutral model. Using this approach, species are taken to be equivalent and trophic relations are not taken into account explicitly. Here we provide a general analytic solution to the local community model of Hubbell's neutral theory of biodiversity by recasting it as an urn model i.e.a Markovian description of states and their transitions. Both stationary and time-dependent distributions are analysed. The stationary distribution -- also called the zero-sum multinomial -- is given in closed form. An approximate form for the time-dependence is obtained by using an expansion of the master equation. The temporal evolution of the approximate distribution is shown to be a good representation for the true temporal evolution for a large range of parameter values.
Funk, Alexander M; Fries, Pascal H; Harvey, Peter; Kenwright, Alan M; Parker, David
2013-02-07
The rates of longitudinal relaxation for ligand nuclei in four isostructural series of lanthanide(III) complexes have been measured by solution state NMR at 295 K at five magnetic fields in the range 4.7-16.5 T. The electronic relaxation time T(le) is a function of both the lanthanide ion and the local ligand field. It needs to be considered when relaxation probes for magnetic resonance applications are devised because it affects the nuclear relaxation, especially over the field range 0.5 to 4.7 T. Analysis of the data, based on Bloch-Redfield-Wangsness theory describing the paramagnetic enhancement of the nuclear relaxation rate has allowed reliable estimates of electronic relaxation times, T(1e), to be obtained using global minimization methods. Values were found in the range 0.10-0.63 ps, consistent with fluctuations in the transient ligand field induced by solvent collision. A refined theoretical model for lanthanide electronic relaxation beyond the Redfield approximation is introduced, which accounts for the magnitude of the ligand field coefficients of order 2, 4, and 6 and their relative contributions to the rate 1/T(le). Despite the considerable variation of these contributions with the nature of the lanthanide ion and its fluctuating ligand field, the theory explains the modest change of measured T(le) values and their remarkable statistical ordering across the lanthanide series. Both experiment and theory indicate that complexes of terbium and dysprosium should most efficiently promote paramagnetic enhancement of the rate of nuclear relaxation.
Modeling Kleinian cosmology with electronic metamaterials
Figueiredo, David; Fumeron, Sébastien; Berche, Betrand; Moraes, Fernando
2016-01-01
This paper deals with the propagation of Klein-Gordon particles in flat background spacetime exhibiting discontinuous metric changes from a Lorentzian signature (-,+,+,+) to a Kleinian signature (-,+,+,-). A formal analogy with the propagation of electrons at a junction between an anisotropic semiconductor and an electronic metamaterial is presented. From that analogy, we study the dynamics of these particles falling onto planar boundary interfaces between these two families of media and show a mirror-like behavior for the particle flux. Finally, the case of a double junction of finite thickness is examined and the possibility of tunneling through it is discussed. A physical link between the metamaterial and the Kleinian slabs is found by calculating the time of flight of the respective traversing particles.
Modeling Kleinian cosmology with electronic metamaterials
Figueiredo, David; Gomes, Felipe A.; Fumeron, Sébastien; Berche, Bertrand; Moraes, Fernando
2016-08-01
This paper deals with the propagation of Klein-Gordon particles in flat background spacetime exhibiting discontinuous metric changes from a Lorentzian signature (-,+,+,+) to a Kleinian signature (-,+,+,-) . A formal analogy with the propagation of electrons at a junction between an anisotropic semiconductor and an electronic metamaterial is presented. From that analogy, we study the dynamics of these particles falling onto planar boundary interfaces between these two families of media and show a mirror-like behavior for the particle flux. Finally, the case of a double junction of finite thickness is examined and the possibility of tunneling through it is discussed. A physical link between the metamaterial and the Kleinian slabs is found by calculating the time of flight of the respective traversing particles.
Sekerzh-Zen'kovich, S. Ya.
2015-10-01
The Cauchy problem for the wave equations of Boussinesq type is treated by considering the initial conditions taken from the solution of generalized Cauchy problem for the potential model of tsunami with some "simple" impulsive source under the assumption that the depth of the liquid is constant. The solutions of the problem under consideration are derived in the form of a single integral giving the wave height at every point of observation at any time moment after the pulsed action of the source. The results of comparing the time history of the the height of tsunami waves at different distances from the source for different values of its characteristic radius (these histories are calculated using two solutions, namely, the solution derived here and the solution known for the potential tsunami model) are described. Conclusions concerning the accuracy of the tested solutions are made.
An integrated radar model solution for mission level performance and cost trades
Hodge, John; Duncan, Kerron; Zimmerman, Madeline; Drupp, Rob; Manno, Mike; Barrett, Donald; Smith, Amelia
2017-05-01
A fully integrated Mission-Level Radar model is in development as part of a multi-year effort under the Northrop Grumman Mission Systems (NGMS) sector's Model Based Engineering (MBE) initiative to digitally interconnect and unify previously separate performance and cost models. In 2016, an NGMS internal research and development (IR and D) funded multidisciplinary team integrated radio frequency (RF), power, control, size, weight, thermal, and cost models together using a commercial-off-the-shelf software, ModelCenter, for an Active Electronically Scanned Array (AESA) radar system. Each represented model was digitally connected with standard interfaces and unified to allow end-to-end mission system optimization and trade studies. The radar model was then linked to the Air Force's own mission modeling framework (AFSIM). The team first had to identify the necessary models, and with the aid of subject matter experts (SMEs) understand and document the inputs, outputs, and behaviors of the component models. This agile development process and collaboration enabled rapid integration of disparate models and the validation of their combined system performance. This MBE framework will allow NGMS to design systems more efficiently and affordably, optimize architectures, and provide increased value to the customer. The model integrates detailed component models that validate cost and performance at the physics level with high-level models that provide visualization of a platform mission. This connectivity of component to mission models allows hardware and software design solutions to be better optimized to meet mission needs, creating cost-optimal solutions for the customer, while reducing design cycle time through risk mitigation and early validation of design decisions.
Minimal parameter implicit solvent model for ab initio electronic structure calculations
Dziedzic, Jacek; Skylaris, Chris-Kriton; Mostofi, Arash A; Payne, Mike C
2011-01-01
We present an implicit solvent model for ab initio electronic structure calculations which is fully self-consistent and is based on direct solution of the nonhomogeneous Poisson equation. The solute cavity is naturally defined in terms of an isosurface of the electronic density according to the formula of Fattebert and Gygi (J. Comp. Chem. 23, 6 (2002)). While this model depends on only two parameters, we demonstrate that by using appropriate boundary conditions and dispersion-repulsion contributions, solvation energies obtained for an extensive test set including neutral and charged molecules show dramatic improvement compared to existing models. Our approach is implemented in, but not restricted to, a linear-scaling density functional theory (DFT) framework, opening the path for self-consistent implicit solvent DFT calculations on systems of unprecedented size, which we demonstrate with calculations on a 2615-atom protein-ligand complex.
Exact Solution in Chaotic Inflation Model with Potential Minima
Institute of Scientific and Technical Information of China (English)
WANG Wen-Fu
2001-01-01
Taking the cosmological expansion rate directly as a function of field , H = H( ), we present a new exact solution to Einstein's equations that describe the evolution of cosmological chaotic inflation model. The inflation is driven by the evolution of scalar field with inflation potential V( ) = λ 2 v2)2.8 ( 2- 2)2.The spectral indices of the scalar density ns and gravitational wave fluctuations ng are computed. The value of ns lies well inside the limits set by the cosmic background explorer satellite.
BPS Solutions to a Generalized Maxwell-Higgs Model
Bazeia, D.(Departamento de Física, Universidade Federal da Paraíba, João Pessoa, PB, 58051-970, Brazil); da Hora, E.; Santos, C. dos(Centro de Física e Departamento de Física e Astronomia, Faculdade de Ciências da Universidade do Porto, 4169-007, Porto, Portugal); Menezes, R.(Departamento de Física, Universidade Federal de Campina Grande, 58109-970 Campina Grande, PB, Brazil)
2012-01-01
We look for topological BPS solutions of an Abelian-Maxwell-Higgs theory endowed by non-standard kinetic terms to both gauge and scalar fields. Here, the non-usual dynamics are controlled by two positive functions, G(|{\\phi}|) and w(|{\\phi}|), which are related to the self-dual scalar potential V(|{\\phi}|) of the model by a fundamental constraint. The numerical results we found present interesting new features, and contribute to the development of the recent issue concerning the study of gene...
Nonzero solutions of nonlinear integral equations modeling infectious disease
Energy Technology Data Exchange (ETDEWEB)
Williams, L.R. (Indiana Univ., South Bend); Leggett, R.W.
1982-01-01
Sufficient conditions to insure the existence of periodic solutions to the nonlinear integral equation, x(t) = ..integral../sup t//sub t-tau/f(s,x(s))ds, are given in terms of simple product and product integral inequalities. The equation can be interpreted as a model for the spread of infectious diseases (e.g., gonorrhea or any of the rhinovirus viruses) if x(t) is the proportion of infectives at time t and f(t,x(t)) is the proportion of new infectives per unit time.
Institute of Scientific and Technical Information of China (English)
Chen Muyan; Yang Hongsheng; Shi Fangfang
2007-01-01
Mixtures of hemolymph from Chlamys farreri with three different anticoagulant solutions were incubated for an hour in vitro , then the ultrastructural alterations of hemocytes were observed , and the aggregation rate was analyzed by using transmission electron microscropy and flow cytometry respectively. The results showed that Formula 3 (glucose 20. 8 g L-1; EDTA 20mM ; sodium chloride 20 g L-1 ; Tris-HCl 0.05M;pH 7. 4) was the desirable anticoagulant solution for C . Farreri hemocytes. Further phagocytosis assay showed that no obvious negative effect was given to the hemocyte phagocytic activity when using Formula 3 as the anticoagulant solution.
Electronic learning and constructivism: a model for nursing education.
Kala, Sasikarn; Isaramalai, Sang-Arun; Pohthong, Amnart
2010-01-01
Nurse educators are challenged to teach nursing students to become competent professionals, who have both in-depth knowledge and decision-making skills. The use of electronic learning methods has been found to facilitate the teaching-learning process in nursing education. Although learning theories are acknowledged as useful guides to design strategies and activities of learning, integration of these theories into technology-based courses appears limited. Constructivism is a theoretical paradigm that could prove to be effective in guiding the design of electronic learning experiences for the purpose of providing positive outcomes, such as the acquisition of knowledge and decision-making skills. Therefore, the purposes of this paper are to: describe electronic learning, present a brief overview of what is known about the outcomes of electronic learning, discuss constructivism theory, present a model for electronic learning using constructivism, and describe educators' roles emphasizing the utilization of the model in developing electronic learning experiences in nursing education.
Power Electronic Packaging Design, Assembly Process, Reliability and Modeling
Liu, Yong
2012-01-01
Power Electronic Packaging presents an in-depth overview of power electronic packaging design, assembly,reliability and modeling. Since there is a drastic difference between IC fabrication and power electronic packaging, the book systematically introduces typical power electronic packaging design, assembly, reliability and failure analysis and material selection so readers can clearly understand each task's unique characteristics. Power electronic packaging is one of the fastest growing segments in the power electronic industry, due to the rapid growth of power integrated circuit (IC) fabrication, especially for applications like portable, consumer, home, computing and automotive electronics. This book also covers how advances in both semiconductor content and power advanced package design have helped cause advances in power device capability in recent years. The author extrapolates the most recent trends in the book's areas of focus to highlight where further improvement in materials and techniques can d...
Predictive modeling of nanoscale domain morphology in solution-processed organic thin films
Schaaf, Cyrus; Jenkins, Michael; Morehouse, Robell; Stanfield, Dane; McDowall, Stephen; Johnson, Brad L.; Patrick, David L.
2017-09-01
The electronic and optoelectronic properties of molecular semiconductor thin films are directly linked to their extrinsic nanoscale structural characteristics such as domain size and spatial distributions. In films prepared by common solution-phase deposition techniques such as spin casting and solvent-based printing, morphology is governed by a complex interrelated set of thermodynamic and kinetic factors that classical models fail to adequately capture, leaving them unable to provide much insight, let alone predictive design guidance for tailoring films with specific nanostructural characteristics. Here we introduce a comprehensive treatment of solution-based film formation enabling quantitative prediction of domain formation rates, coverage, and spacing statistics based on a small number of experimentally measureable parameters. The model combines a mean-field rate equation treatment of monomer aggregation kinetics with classical nucleation theory and a supersaturation-dependent critical nucleus size to solve for the quasi-two-dimensional temporally and spatially varying monomer concentration, nucleation rate, and other properties. Excellent agreement is observed with measured nucleation densities and interdomain radial distribution functions in polycrystalline tetracene films. Numerical solutions lead to a set of general design rules enabling predictive morphological control in solution-processed molecular crystalline films.
Finite-bias electronic transport of molecules in a water solution
Rungger, Ivan
2010-06-04
The effects of water wetting conditions on the transport properties of molecular nanojunctions are investigated theoretically by using a combination of empirical-potential molecular-dynamics and first-principles electronic-transport calculations. These are at the level of the nonequilibrium Green’s-function method implemented for self-interaction corrected density-functional theory. We find that water effectively produces electrostatic gating to the molecular junction with a gating potential determined by the time-averaged water dipole field. Such a field is large for the polar benzene-dithiol molecule, resulting in a transmission spectrum shifted by about 0.6 eV with respect to that of the dry junction. The situation is drastically different for carbon nanotubes (CNTs). In fact, because of their hydrophobic nature the gating is almost negligible so that the average transmission spectrum of wet Au/CNT/Au junctions is essentially the same as that in dry conditions. This suggests that CNTs can be used as molecular interconnects also in water-wet situations, for instance, as tips for scanning tunnel microscopy in solution or in biological sensors.
Forecasting relativistic electron flux using dynamic multiple regression models
Directory of Open Access Journals (Sweden)
H.-L. Wei
2011-02-01
Full Text Available The forecast of high energy electron fluxes in the radiation belts is important because the exposure of modern spacecraft to high energy particles can result in significant damage to onboard systems. A comprehensive physical model of processes related to electron energisation that can be used for such a forecast has not yet been developed. In the present paper a systems identification approach is exploited to deduce a dynamic multiple regression model that can be used to predict the daily maximum of high energy electron fluxes at geosynchronous orbit from data. It is shown that the model developed provides reliable predictions.
Peculiarities of designing Holistic Electronic Government Services Integration Model
Directory of Open Access Journals (Sweden)
Tadas Limba
2011-12-01
Full Text Available Purpos– the aim ok this paper is to develop a Holistic Electronic Government Services Integration Model which could ensure the efficient integration of electronic government services in the local self-government level.Methodolog– the following analyses have been carried out in thirkpaper: theoretical-systematic; normative and conceptual comparative analysis of the researcha A method of modeling has also been applied.Finding– the scientific work analyzes the improvement opportunities of the models of electronic government services and their application alternatives in Lithuanian municipalities. The newly developed model of electronic government services that has been designed basng on the principle of integrating online expert consultation is primarily targeted at improvement of inside processes’ changes of an organization. Practicing the application of that model in the local self-government level starting with improvement of inside processes of an organization should help adapt more accurately and efficiently to the changing needs of the society while providing electronic government services, thus establishing a higher public value.Practical implication– the practical novelty of work is reflected not only through the integration opportunities’ assessment of the principle of online expert consultation services into the theoretical models of electronic government services that have already been developed by the scientists, but also on the basis of this principle there has been created a “Holistic Electronic Government Services Integration Model” in accordance with “E-Diamond” model basis and its practical application realization with the design of “The project of implementing the principle of online expert consultation on the model of electronic government services” for the future investigations.Originalit– the systematic, comparative analysis of the models of electronic government services carried out in the scientific
A polaron model for electron transfer in globular proteins.
Chuev, G N; Lakhno, V D
1993-07-07
Polaron models have been considered for the electron states in protein globules existing in a solvent. These models account for two fundamental effects, viz, polarization interaction of an electron with the conformational vibrations and the heterogeneity of the medium. Equations have been derived to determine the electron state in a protein globule. The parameters of this state show that it is an extended state with an energy of 2 eV. The electron transfer rate for cyt C self-exchange reaction has been calculated in the polaron model. Reorganization energy, tunneling matrix element and the rate constant have also been estimated. The results are compared with experimental data. The influence of model parameters on the significance of the data obtained has been studied. The potentialities of the model are discussed.
Dynamic pricing models for electronic business
Indian Academy of Sciences (India)
Y Narahari; C V L Raju; K Ravikumar; Sourabh Shah
2005-04-01
Dynamic pricing is the dynamic adjustment of prices to consumers depending upon the value these customers attribute to a product or service. Today’s digital economy is ready for dynamic pricing; however recent research has shown that the prices will have to be adjusted in fairly sophisticated ways, based on sound mathematical models, to derive the beneﬁts of dynamic pricing. This article attempts to survey different models that have been used in dynamic pricing. We ﬁrst motivate dynamic pricing and present underlying concepts, with several examples, and explain conditions under which dynamic pricing is likely to succeed. We then bring out the role of models in computing dynamic prices. The models surveyed include inventory-based models, data-driven models, auctions, and machine learning. We present a detailed example of an e-business market to show the use of reinforcement learning in dynamic pricing.
Lin, Zhaoyang; Chen, Yu; Yin, Anxiang; He, Qiyuan; Huang, Xiaoqing; Xu, Yuxi; Liu, Yuan; Zhong, Xing; Huang, Yu; Duan, Xiangfeng
2014-11-12
Low-temperature solution-processed electronic materials on plastic substrates are of considerable interest for flexible electronics. Solution dispersible inorganic nanostructures (e.g., zero-dimensional (0D) quantum dots or one-dimensional (1D) nanowires) have emerged as interesting ink materials for low-temperature solution processing of electronic thin films on flexible substrates, but usually with limited performance due to the large number of grain boundaries (0D) or incomplete surface coverage (1D). Here, we report two-dimensional (2D) colloidal nanoplates of layered materials as a new ink material for solution assembly of high-performance electronic thin films. The 2D colloidal nanoplates exhibit few dangling bonds and represent an ideal geometry for the assembly of highly uniform continuous thin films with greatly reduced grain boundaries dictated by large-area conformal plane-plane contact with atomically flat/clean interfaces. It can therefore promise efficient charge transport across neighboring nanoplates and throughout the entire thin film to enable unprecedented electronic performance. We show that Bi2Se3 and Bi2Te3 nanoplates can be synthesized with well-controlled thickness (6-15 nm) and lateral dimension (0.5-3 μm) and can be used for the assembly of highly uniform continuous thin films with a full surface coverage and an excellent room temperature carrier mobility >100 cm(2)·V(-1)·s(-1), approaching that of chemical vapor deposition grown materials. Our study demonstrates a general strategy to using 2D nanoplates as a unique building block for the construction of high-performance electronic thin films on plastic substrates for future flexible electronics and optoelectronics.
Numerical solution of linear models in economics: The SP-DG model revisited
T. Andrade, G. Faria, V. Leite, F. Verona, M. Viegas; Afonso, O.; P.B. Vasconcelos
2007-01-01
In general, complex and large dimensional models are needed to solve real economic problems. Due to these characteristics, there is either no analytical solution for them or they are not attainable. As a result, solutions can be only obtained through numerical methods. Thus, the growing importance of computers in Economics is not surprising. This paper focuses on an implementation of the SP-DG model, using Matlab,developed by the students as part of the Computational Economics course. We also...
Assessing uncertainties in solute transport models: Upper Narew case study
Osuch, M.; Romanowicz, R.; Napiórkowski, J. J.
2009-04-01
This paper evaluates uncertainties in two solute transport models based on tracer experiment data from the Upper River Narew. Data Based Mechanistic and transient storage models were applied to Rhodamine WT tracer observations. We focus on the analysis of uncertainty and the sensitivity of model predictions to varying physical parameters, such as dispersion and channel geometry. An advection-dispersion model with dead zones (Transient Storage model) adequately describes the transport of pollutants in a single channel river with multiple storage. The applied transient storage model is deterministic; it assumes that observations are free of errors and the model structure perfectly describes the process of transport of conservative pollutants. In order to take into account the model and observation errors, an uncertainty analysis is required. In this study we used a combination of the Generalized Likelihood Uncertainty Estimation technique (GLUE) and the variance based Global Sensitivity Analysis (GSA). The combination is straightforward as the same samples (Sobol samples) were generated for GLUE analysis and for sensitivity assessment. Additionally, the results of the sensitivity analysis were used to specify the best parameter ranges and their prior distributions for the evaluation of predictive model uncertainty using the GLUE methodology. Apart from predictions of pollutant transport trajectories, two ecological indicators were also studied (time over the threshold concentration and maximum concentration). In particular, a sensitivity analysis of the length of "over the threshold" period shows an interesting multi-modal dependence on model parameters. This behavior is a result of the direct influence of parameters on different parts of the dynamic response of the system. As an alternative to the transient storage model, a Data Based Mechanistic approach was tested. Here, the model is identified and the parameters are estimated from available time series data using
Teaching Behavioral Modeling and Simulation Techniques for Power Electronics Courses
Abramovitz, A.
2011-01-01
This paper suggests a pedagogical approach to teaching the subject of behavioral modeling of switch-mode power electronics systems through simulation by general-purpose electronic circuit simulators. The methodology is oriented toward electrical engineering (EE) students at the undergraduate level, enrolled in courses such as "Power…
Electron thermal transport barriers in RTP: experiment and modelling
Schilham, A.M.R.; Hogeweij, G. M. D.; Cardozo, N. J. L.
2001-01-01
Experiments in which very localized electron cyclotron heating (ECH) is scanned through the RTP plasma show sharp transitions, in which the electron temperature profile abruptly changes shape. The phenomenology-the profiles shapes, the sharp transitions-can be reproduced with a transport model which
Temperature dependence of electronic heat capacity in Holstein model
Fialko, N S; Lakhno, V D
2015-01-01
The dynamics of charge migration was modeled to calculate temperature dependencies of its thermodynamic equilibrium values such as energy and electronic heat capacity in homogeneous adenine fragments. The energy varies from nearly polaron one at T~0 to midpoint of the conductivity band at high temperatures. The peak on the graph of electronic heat capacity is observed at the polaron decay temperature.
Teaching Behavioral Modeling and Simulation Techniques for Power Electronics Courses
Abramovitz, A.
2011-01-01
This paper suggests a pedagogical approach to teaching the subject of behavioral modeling of switch-mode power electronics systems through simulation by general-purpose electronic circuit simulators. The methodology is oriented toward electrical engineering (EE) students at the undergraduate level, enrolled in courses such as "Power…
Problem Resolution through Electronic Mail: A Five-Step Model.
Grandgenett, Neal; Grandgenett, Don
2001-01-01
Discusses the use of electronic mail within the general resolution and management of administrative problems and emphasizes the need for careful attention to problem definition and clarity of language. Presents a research-based five-step model for the effective use of electronic mail based on experiences at the University of Nebraska at Omaha.…
An Algorithm for Solution of an Interval Valued EOQ Model
Directory of Open Access Journals (Sweden)
Susovan CHAKRABORTTY
2013-01-01
Full Text Available This paper deals with the problem of determining the economic order quantity (EOQin the interval sense. A purchasing inventory model with shortages and lead time, whose carryingcost, shortage cost, setup cost, demand quantity and lead time are considered as interval numbers,instead of real numbers. First, a brief survey of the existing works on comparing and ranking anytwo interval numbers on the real line is presented. A common algorithm for the optimum productionquantity (Economic lot-size per cycle of a single product (so as to minimize the total average cost isdeveloped which works well on interval number optimization under consideration. A numerical exampleis presented for better understanding the solution procedure. Finally a sensitive analysis of the optimalsolution with respect to the parameters of the model is examined.
Micera, G.; And Others
1984-01-01
Background, procedures, and results are provided for an experiment which examines, through electron spin resonance spectroscopy, complex species formed by cupric and 2,6-dihydroxybenzoate ions in aqueous solutions. The experiment is illustrative of several aspects of inorganic and coordination chemistry, including the identification of species…
Directory of Open Access Journals (Sweden)
Juan Soto
2006-09-01
Full Text Available An electronic tongue for the qualitative analysis of aqueous solutions of salts hasbeen developed. The following set of electrodes was used: RuO2, Ag, and Cu in thick-filmtechnology and Au, Pb, Zn and Ni as small bars of the corresponding metal. The response ofthe designed Ã¢Â€Âœelectronic tongueÃ¢Â€Â was tested on a family of samples containing pure salt andcomplex mixtures. The electrodes were used as potentiometric un-specific sensors and thee.m.f. of each electrode in contact with a certain aqueous solution was used as input signalfor a PCA analysis. The study showed that the set of electrodes were capable to discriminatebetween aqueous solutions of salts basically by their different content in anions and cations(the anions SO42-, Cl-, PO4H2-, CO3H-, NO3- and cations Na+ and K+ were studied. In orderto better analyze the basis for the discrimination power shown by the electronic tongue, aquantitative analysis was also envisaged. A fair estimation of the concentrations of thedifferent ions in the solutions studied appeared to be possible using this electronic tonguedesign.Keywords:
Solution-Processed Nb:SnO2 Electron Transport Layer for Efficient Planar Perovskite Solar Cells.
Ren, Xiaodong; Yang, Dong; Yang, Zhou; Feng, Jiangshan; Zhu, Xuejie; Niu, Jinzhi; Liu, Yucheng; Zhao, Wangen; Liu, Shengzhong Frank
2017-01-25
Electron transport layer (ETL), facilitating charge carrier separation and electron extraction, is a key component in planar perovskite solar cells (PSCs). We developed an effective ETL using low-temperature solution-processed Nb-doped SnO2 (Nb:SnO2). Compared to the pristine SnO2, the power conversion efficiency of PSCs based on Nb:SnO2 ETL is raised to 17.57% from 15.13%. The splendid performance is attributed to the excellent optical and electronic properties of the Nb:SnO2 material, such as smooth surface, high electron mobility, appropriate electrical conductivity, therefore making a better growth platform for a high quality perovskite absorber layer. Experimental analyses reveal that the Nb:SnO2 ETL significantly enhances the electron extraction and effectively suppresses charge recombination, leading to improved solar cell performance.
Exact solutions of the high dimensional hard-core Fermi-Hubbard model
Institute of Scientific and Technical Information of China (English)
PAN; Feng
2001-01-01
［1］Hubbard, J., Electron correlations in narrow energy bands, Proc. R. Soc. London, A, 963, 276: 238.［2］Hubbard, J., Electron correlations in narrow energy bands II. The degenerate band case, Proc. R. Soc. London A, 963, A277: 237.［3］Anderson, P. W., The resonating valence bond state in La2CuOand superconductivity, Science, 987, 235: 96.［4］Lieb, E. H, Wu, F. Y., Absence of Mott transition in an exact solution of the short-range one-band model in one dimension, Phys. Rev. Lett., 968, 20: 445.［5］Ogata, M., Shiba, H., Bethe-ansatz wave function, momentum distribution, and spin correlation in the one-dimensional strongly correlated Hubbard model, Phys. Rev., 990, B4: 326.［6］Ogata, M., Sugiyama, T., Shiba, H., Magnetic-field effects on the correlation functions in the one-dimensional strongly correlated Hubbard model, Phys. Rev., 990, B43: 840.［7］Mei, C., Chen, L., Study of the interaction between two electrons in the single band Hubbard model, Z. Phys., 988, B72: 429.［8］Caspers, W. J., Iske, P. L., Exact spectrum for n electrons in the single band Hubbard model, Physica, 989, A, 57: 033.［9］Kirson, M. W., A dynamical supersymmetry in the Hubbard model, Phys. Rev. Lett., 997, 78: 24.［10］Woynarovich, F., Excitations with complex wavefunctions in a Hubbard chain: II. States with several pairs of complex wavenumbers, J. Phys., 982, C5: 97.
An Electronic Tongue Designed to Detect Ammonium Nitrate in Aqueous Solutions
Directory of Open Access Journals (Sweden)
Inmaculada Campos
2013-10-01
Full Text Available An electronic tongue has been developed to monitor the presence of ammonium nitrate in water. It is based on pulse voltammetry and consists of an array of eight working electrodes (Au; Pt; Rh; Ir; Cu; Co; Ag and Ni encapsulated in a stainless steel cylinder. In a first step the electrochemical response of the different electrodes was studied in the presence of ammonium nitrate in water in order to further design the wave form used in the voltammetric tongue. The response of the electronic tongue was then tested in the presence of a set of 15 common inorganic salts; i.e.; NH4NO3; MgSO4; NH4Cl; NaCl; Na2CO3; (NH42SO4; MgCl2; Na3PO4; K2SO4; K2CO3; CaCl2; NaH2PO4; KCl; NaNO3; K2HPO4. A PCA plot showed a fairly good discrimination between ammonium nitrate and the remaining salts studied. In addition Fuzzy Art map analyses determined that the best classification was obtained using the Pt; Co; Cu and Ni electrodes. Moreover; PLS regression allowed the creation of a model to correlate the voltammetric response of the electrodes with concentrations of ammonium nitrate in the presence of potential interferents such as ammonium chloride and sodium nitrate.
Energy Technology Data Exchange (ETDEWEB)
Hagelaar, G J M; Pitchford, L C [Centre de Physique des Plasmas et de leurs Applications de Toulouse, Universite Paul Sabatier, 118 route de Narbonne, 31062 Toulouse Cedex 9 (France)
2005-11-15
Fluid models of gas discharges require the input of transport coefficients and rate coefficients that depend on the electron energy distribution function. Such coefficients are usually calculated from collision cross-section data by solving the electron Boltzmann equation (BE). In this paper we present a new user-friendly BE solver developed especially for this purpose, freely available under the name BOLSIG+, which is more general and easier to use than most other BE solvers available. The solver provides steady-state solutions of the BE for electrons in a uniform electric field, using the classical two-term expansion, and is able to account for different growth models, quasi-stationary and oscillating fields, electron-neutral collisions and electron-electron collisions. We show that for the approximations we use, the BE takes the form of a convection-diffusion continuity-equation with a non-local source term in energy space. To solve this equation we use an exponential scheme commonly used for convection-diffusion problems. The calculated electron transport coefficients and rate coefficients are defined so as to ensure maximum consistency with the fluid equations. We discuss how these coefficients are best used in fluid models and illustrate the influence of some essential parameters and approximations.
Jensen, Lasse; van Duijnen, Piet Th.; Snijders, Jaap G.
2003-08-01
A discrete solvent reaction field model for calculating frequency-dependent molecular linear response properties of molecules in solution is presented. The model combines a time-dependent density functional theory (QM) description of the solute molecule with a classical (MM) description of the discrete solvent molecules. The classical solvent molecules are represented using distributed atomic charges and polarizabilities. All the atomic parameters have been chosen so as to describe molecular gas phase properties of the solvent molecule, i.e., the atomic charges reproduce the molecular dipole moment and the atomic polarizabilities reproduce the molecular polarizability tensor using a modified dipole interaction model. The QM/MM interactions are introduced into the Kohn-Sham equations and all interactions are solved self-consistently, thereby allowing for the solute to be polarized by the solvent. Furthermore, the inclusion of polarizabilities in the MM part allows for the solvent molecules to be polarized by the solute and by interactions with other solvent molecules. Initial applications of the model to calculate the vertical electronic excitation energies and frequency-dependent molecular polarizability of a water molecule in a cluster of 127 classical water molecules are presented. The effect of using different exchange correlation (xc)-potentials is investigated and the results are compared with results from wave function methods combined with a similar solvent model both at the correlated and uncorrelated level of theory. It is shown that accurate results in agreement with correlated wave function results can be obtained using xc-potentials with the correct asymptotic behavior.
Polaron Model of the Formation of Hydrated Electron States
2015-01-01
A computer simulation of the formation of photoexcited electrons in water is performed within the framework of a dynamic model. The obtained results are discussed in comparison with experimental data and theoretical estimates.
Blocking layer modeling for temperature analysis of electron transfer ...
African Journals Online (AJOL)
Blocking layer modeling for temperature analysis of electron transfer rate in quantum dot sensitized solar cells. ... Journal of Fundamental and Applied Sciences ... of the quantum dots and free energy of system and finally the Marcus equation.
Electronic Modeling and Design for Extreme Temperatures Project
National Aeronautics and Space Administration — We are developing CAD tools, models and methodologies for electronics design for circuit operation in extreme environments with focus on very low temperatures...
Modelling and implementing electronic health records in Denmark
DEFF Research Database (Denmark)
Bernstein, Knut; Rasmussen, Morten Bruun; Vingtoft, Søren;
2003-01-01
The Danish Health IT strategy points out that integration between electronic health records (EHR) systems has a high priority. This paper reporst reports new tendencies in modelling and integration platforms globally and how this is reflected in the natinal development.......The Danish Health IT strategy points out that integration between electronic health records (EHR) systems has a high priority. This paper reporst reports new tendencies in modelling and integration platforms globally and how this is reflected in the natinal development....
Modelling and implementing electronic health records in Denmark
DEFF Research Database (Denmark)
Bernstein, Knut; Rasmussen, Morten Bruun; Vingtoft, Søren
2003-01-01
The Danish Health IT strategy points out that integration between electronic health records (EHR) systems has a high priority. This paper reporst reports new tendencies in modelling and integration platforms globally and how this is reflected in the natinal development.......The Danish Health IT strategy points out that integration between electronic health records (EHR) systems has a high priority. This paper reporst reports new tendencies in modelling and integration platforms globally and how this is reflected in the natinal development....
Peculiarities of designing Holistic Electronic Government Services Integration Model
Tadas Limba
2011-01-01
Purpose – the aim ok this paper is to develop a Holistic Electronic Government Services Integration Model which could ensure the efficient integration of electronic government services in the local self-government level. Methodology - the following analyses have been carried out in thirkpaper: theoretical-systematic; normative and conceptual comparative analysis of the researcha A method of modeling has also been applied. Finding – the scientific work analyzes the improvement opportunities of...
Modeling Electronic Circular Dichroism within the Polarizable Embedding Approach
DEFF Research Database (Denmark)
Nørby, Morten S; Olsen, Jógvan Magnus Haugaard; Steinmann, Casper
2017-01-01
We present a systematic investigation of the key components needed to model single chromophore electronic circular dichroism (ECD) within the polarizable embedding (PE) approach. By relying on accurate forms of the embedding potential, where especially the inclusion of local field effects...... sampling. We show that a significant number of snapshots are needed to avoid artifacts in the calculated electronic circular dichroism parameters due to insufficient configurational sampling, thus highlighting the efficiency of the PE model....
DEFF Research Database (Denmark)
Larsen, Erik Hviid; Sørensen, Jakob Balslev; Sørensen, Jens Nørkær
2000-01-01
A mathematical model of an absorbing leaky epithelium is developed for analysis of solute coupled water transport. The non-charged driving solute diffuses into cells and is pumped from cells into the lateral intercellular space (lis). All membranes contain water channels with the solute passing...... concentration of fluid emerging from lis is then significantly larger than the concentration in lis. Thus, in absence of external driving forces the model generates isotonic transport provided a component of the solute flux emerging downstream lis is taken up by cells through the serosal membrane and pumped...... back into lis, i.e., the solute would have to be recirculated. With input variables from toad intestine (Nedergaard, S., E.H. Larsen, and H.H. Ussing, J. Membr. Biol. 168:241-251), computations predict that 60-80% of the pumped flux stems from serosal bath in agreement with the experimental estimate...
Joshi, Nitin; Ojha, C. S. P.; Sharma, P. K.
2012-10-01
In this study a conceptual model that accounts for the effects of nonequilibrium contaminant transport in a fractured porous media is developed. Present model accounts for both physical and sorption nonequilibrium. Analytical solution was developed using the Laplace transform technique, which was then numerically inverted to obtain solute concentration in the fracture matrix system. The semianalytical solution developed here can incorporate both semi-infinite and finite fracture matrix extent. In addition, the model can account for flexible boundary conditions and nonzero initial condition in the fracture matrix system. The present semianalytical solution was validated against the existing analytical solutions for the fracture matrix system. In order to differentiate between various sorption/transport mechanism different cases of sorption and mass transfer were analyzed by comparing the breakthrough curves and temporal moments. It was found that significant differences in the signature of sorption and mass transfer exists. Applicability of the developed model was evaluated by simulating the published experimental data of Calcium and Strontium transport in a single fracture. The present model simulated the experimental data reasonably well in comparison to the model based on equilibrium sorption assumption in fracture matrix system, and multi rate mass transfer model.
Directory of Open Access Journals (Sweden)
Maria de Hoyos Guajardo, Ph.D. Candidate, M.Sc., B.Eng.
2004-11-01
Full Text Available The theory that is presented below aims to conceptualise how a group of undergraduate students tackle non-routine mathematical problems during a problem-solving course. The aim of the course is to allow students to experience mathematics as a creative process and to reflect on their own experience. During the course, students are required to produce a written ‘rubric’ of their work, i.e., to document their thoughts as they occur as well as their emotionsduring the process. These ‘rubrics’ were used as the main source of data.Students’ problem-solving processes can be explained as a three-stage process that has been called ‘solutioning’. This process is presented in the six sections below. The first three refer to a common area of concern that can be called‘generating knowledge’. In this way, generating knowledge also includes issues related to ‘key ideas’ and ‘gaining understanding’. The third and the fourth sections refer to ‘generating’ and ‘validating a solution’, respectively. Finally, once solutions are generated and validated, students usually try to improve them further before presenting them as final results. Thus, the last section deals with‘improving a solution’. Although not all students go through all of the stages, it may be said that ‘solutioning’ considers students’ main concerns as they tackle non-routine mathematical problems.
Some exact solutions of magnetized viscous model in string cosmology
Indian Academy of Sciences (India)
C P Singh
2014-07-01
In this paper, we study anisotropic Bianchi-V Universe with magnetic field and bulk viscous fluid in string cosmology. Exact solutions of the field equations are obtained by using the equation of state (EoS) for a cloud of strings, and a relationship between bulk viscous coefficient and scalar expansion. The bulk viscous coefficient is assumed to be inversely proportional to the expansion scalar. It is interesting to examine the effects of magnetized bulk viscous string model in early and late stages of evolution of the Universe. This paper presents different string models like geometrical (Nambu string), Takabayasi (p-string) and Reddy string models by taking certain physical conditions. We discuss the nature of classical potential for viscous fluid with and without magnetic field. The presence of bulk viscosity stops the Universe from becoming empty in its future evolution. It is observed that the Universe expands with decelerated rate in the presence of viscous fluid with magnetic field whereas, it expands with marginal inflation in the presence of viscous fluid without magnetic field. The other physical and geometrical aspects of each string model are discussed in detail.
Exact solutions to model surface and volume charge distributions
Mukhopadhyay, S.; Majumdar, N.; Bhattacharya, P.; Jash, A.; Bhattacharya, D. S.
2016-10-01
Many important problems in several branches of science and technology deal with charges distributed along a line, over a surface and within a volume. Recently, we have made use of new exact analytic solutions of surface charge distributions to develop the nearly exact Boundary Element Method (neBEM) toolkit. This 3D solver has been successful in removing some of the major drawbacks of the otherwise elegant Green's function approach and has been found to be very accurate throughout the computational domain, including near- and far-field regions. Use of truly distributed singularities (in contrast to nodally concentrated ones) on rectangular and right-triangular elements used for discretizing any three-dimensional geometry has essentially removed many of the numerical and physical singularities associated with the conventional BEM. In this work, we will present this toolkit and the development of several numerical models of space charge based on exact closed-form expressions. In one of the models, Particles on Surface (ParSur), the space charge inside a small elemental volume of any arbitrary shape is represented as being smeared on several surfaces representing the volume. From the studies, it can be concluded that the ParSur model is successful in getting the estimates close to those obtained using the first-principles, especially close to and within the cell. In the paper, we will show initial applications of ParSur and other models in problems related to high energy physics.
A potential model for sodium chloride solutions based on the TIP4P/2005 water model
Benavides, A. L.; Portillo, M. A.; Chamorro, V. C.; Espinosa, J. R.; Abascal, J. L. F.; Vega, C.
2017-09-01
Despite considerable efforts over more than two decades, our knowledge of the interactions in electrolyte solutions is not yet satisfactory. Not even one of the most simple and important aqueous solutions, NaCl(aq), escapes this assertion. A requisite for the development of a force field for any water solution is the availability of a good model for water. Despite the fact that TIP4P/2005 seems to fulfill the requirement, little work has been devoted to build a force field based on TIP4P/2005. In this work, we try to fill this gap for NaCl(aq). After unsuccessful attempts to produce accurate predictions for a wide range of properties using unity ionic charges, we decided to follow recent suggestions indicating that the charges should be scaled in the ionic solution. In this way, we have been able to develop a satisfactory non-polarizable force field for NaCl(aq). We evaluate a number of thermodynamic properties of the solution (equation of state, maximum in density, enthalpies of solution, activity coefficients, radial distribution functions, solubility, surface tension, diffusion coefficients, and viscosity). Overall the results for the solution are very good. An important achievement of our model is that it also accounts for the dynamical properties of the solution, a test for which the force fields so far proposed failed. The same is true for the solubility and for the maximum in density where the model describes the experimental results almost quantitatively. The price to pay is that the model is not so good at describing NaCl in the solid phase, although the results for several properties (density and melting temperature) are still acceptable. We conclude that the scaling of the charges improves the overall description of NaCl aqueous solutions when the polarization is not included.
Modelling low energy electron interactions for biomedical uses of radiation
Energy Technology Data Exchange (ETDEWEB)
Fuss, M; Garcia, G [Instituto de Fisica Fundamental, Consejo Superior de Investigaciones CientIficas (CSIC), Serrano 113-bis, 28006 Madrid (Spain); Munoz, A; Oller, J C [Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas (CIEMAT), Avenida Complutense 22, 28040 Madrid (Spain); Blanco, F [Departamento de Fisica Atomica, Molecular y Nuclear, Universidad Complutense de Madrid, Avenida Complutense s.n., 28040 Madrid (Spain); Limao-Vieira, P [Departamento de Fisica, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Huerga, C; Tellez, M [Hospital Universitario La Paz, paseo de la Castellana 261, 28046 Madrid (Spain); Hubin-Fraskin, M J [Department of Chemistry, University of Liege, 4000 Liege 1 (Belgium); Nixon, K; Brunger, M, E-mail: g.garcia@imaff.cfmac.csic.e [School of Chemistry, Physics and Earth Sciences, Flinders University, GPO Box 2100, Adelaide, SA 5001 (Australia)
2009-11-15
Current radiation based medical applications in the field of radiotherapy, radio-diagnostic and radiation protection require modelling single particle interactions at the molecular level. Due to their relevance in radiation damage to biological systems, special attention should be paid to include the effect of low energy secondary electrons. In this study we present a single track simulation procedure for photons and electrons which is based on reliable experimental and theoretical cross section data and the energy loss distribution functions derived from our experiments. The effect of including secondary electron interactions in this model will be discussed.
Staszewska, G.
1981-06-01
A new approach to the solution of coupled equations involved in electron-ion and electron-atom scattering problems is proposed. This method is a combination of iteration and variation procedures. The main advantage of this method is that exchange terms can be calculated in a direct and straightforward manner. The method is based on the Lippmann-Schwinger equation and does not require trial functions satisfying appropriate boundary conditions. Using the Volterra formulation one can find the solution on an interval determined by the range of the exchange potential and the long-range potential terms can be taken into account by a projection procedure giving the asymptotic value of the reactance matrix. The method is tested on the case of electron-hydrogen atom scattering in the 1s-2s and 1s-2s-2p approximation. We have adapted the method proposed originally by Rayski to obtain solutions of coupled equations involved in electron-ion and electron-atom scattering. As mentioned in section 1 the construction of the method secures an automatic fulfilment of the boundary conditions. It allows an easy calculation of the exchange potential as well as an estimation of the introduced approximation. It gives also a possibility of detecting any spurious convergence. Moreover, it is important that this formalism can be applied in the case of normalized as well as unnormalized initial integral equations. This fact is of special importance in the case of long-range interactions. When the method is used for unnormalized (Volterra) equations it allows application of a very convenient projection procedure for treating the long-range terms in the direct potential. Electron-hydrogen atom collisions are investigated as a numerical illustration of the method. In the 1s-2s approximation the normalized equations were solved, while in the 1s-2s-2p approximation the solution was obtained with the help of Volterra equations and the long-range terms of the direct potential were taken into account
Energy Technology Data Exchange (ETDEWEB)
Anderson, R.F.; Patel, K.B. (Mount Vernon Hospital, Northwood (United Kingdom). Gray Lab.); Wilson, W.R. (Univ. of Auckland School of Medicine (New Zealand))
1991-12-07
The reactions of the aquated electron (e{sub aq}{sup -}) with intercalators of high reduction potential (nitracrine and related basic nitroacridines) has been investigated by pulse radiolysis in the presence of DNA in aqueous solution. Under conditions where the majority of the e{sub aq}{sup -} species react initially with DNA bases (high DNA:drug ratios) a slower subsequent electron transfer to the intercalator was observed. The rate of this intra-complex transfer, expressed as DNA base pairs traversed per second, was in the range (1.2-3.1) x 10{sup 5} base pairs s{sup -1} and increased in order of the one-electron reduction potentials of the DNA-bound intercalators. No transfer was seen to the much less electron affinic des-nitro analogue of the nitroacridines. Only a small proportion of the initial DNA base radicals ({<=}50%) underwent this intra-complex electron transfer. Even for the most efficient electron trap, nitracrine, the apparent mean electron migration distance was only three base pairs. A slow secondary reduction of nitroacridines ((0.08-5.0) x 10{sup 4} base pairs s{sup -1}) was also observed with a proportion of the essentially immobile {sup .}OH-induced DNA radicals. This secondary reaction may well serve as a measure of the mobility of the DNa-bound intercalators. This study therefore implies a lack of extensive migration of DNA-associated electrons in aqueous solution, although it does not exclude the possibility that more mobile electrons produced by direct ionization of DNA might migrate over large distances. (author).
Electronic Service Architecture Model Assessment of Conformity to Cloud Computing Key Features
Stipravietis, P; Žeiris, E; Ziema, M
2013-01-01
The research examines electronic service execution possibilities in cloud computing environment and the key features of cloud computing. It also offers a method which allows quantitatively assess the conformity of existing e-service architecture model to cloud computing key features.The method allows evaluating the amount of necessary transformations and their efficiency. The offered solution is verified using the business process administered by Motor Insurance Bureau...
Synthesis and characterization of nanocrystalline apatites from solution modeling human blood
Solodyankina, Anna; Nikolaev, Anton; Frank-Kamenetskaya, Olga; Golovanova, Olga
2016-09-01
Present paper is devoted to the research of the calcification processes in the blood plasma of human body. Spontaneous crystallization from the solution modeling the inorganic part of the blood plasma has been carried out. Obtained precipitates were studied by the various instrumental methods (X-ray powder diffraction, Fourier-transformed infrared spectroscopy, scanning electron microscopy, electron probe microanalysis and gas-volumetric method). All gathered data allow to summarize that nonstoichiometric carbonated hydroxyapatite with low crystallinity (CSD lengths 18-28 nm), high water content and small amount of chlorine ion was obtained throughout the syntheses. Part of vacancies at the Ca sites varies from 0.17 to 0.87; the value of the Cat/(P + C) ratio-from 1.52 to 1.64 (where Cat = Ca2+ + Na+ + K+ + Mg2+). The poor crystallized synthetic apatites with high carbonate ion content (from 4.34 to 5.54 wt%) and c parameter (6.888-6.894 Å) are analogues of the apatites of the pathological cardiovascular deposits. They can be obtained from the solution modeling human blood plasma by the inorganic components with calcium phosphate supersaturation 25 and 50 and with 10 and 12 weeks experiment time.
Energy Technology Data Exchange (ETDEWEB)
Gonzalez Vanderhaghen, D.E
1998-12-31
In a search for solutions to environmental pollution problems, radiolysis has proved to be an innovative technique for the removal of organic chemical pollutants in aqueous solution. Radiolysis has shown many advantages over many other techniques, as highly reactive species formed in water by ionizing radiation oxidize organic pollutants breaking down organic molecules to final simple products by oxidation to carbon dioxide and water in a complete oxidation. Our work consisted in doing some experiments in radiolysis with simulated polluted water to help us understand this technique and also develop, in a near future, a project for large scale water treatment. Our project includes the application of a Pelletron type Mexican made Electron Accelerator, which will affirm its capability and usefulness in performing investigation in this field of study. Experiments consisted in treating benzene, toluene and phenol aqueous solutions with an Electron Beam (0.48-0.55 MeV; 24 {mu}A). Two concentrations were used for each compound: 5 and 20 ppm (mg/l) for benzene and toluene; 10 and 50 ppm for phenol. Solutions were prepared with pure, mineral free water and two different p H (5.9), in order to study the effect of concentration and p H on removal efficiency, but avoiding the interference of radical scavengers. Results obtained coincide with the ones reported by Cooper, Nickelsen and Kurucz; highly efficient removal was achieved for benzene (>99.8%), toluene (>98.0%) and phenol (>88%). There was no visible important effect of p H on radiolysis efficiency for benzene nor toluene, phenol however, showed lower removal efficiency in acidic conditions. Concentration of aqueous solutions, nevertheless, did show an important effect at low doses for phenol. Results obtained reveal the importance of this technique in water pollution control and water remedial as expressed by Cooper, Nickelsen and Kurucz, who have studied radiolysis of organic compounds and apply this technique in water
Template and Model Driven Development of Standardized Electronic Health Records.
Kropf, Stefan; Chalopin, Claire; Denecke, Kerstin
2015-01-01
Digital patient modeling targets the integration of distributed patient data into one overarching model. For this integration process, both a theoretical standard-based model and information structures combined with concrete instructions in form of a lightweight development process of single standardized Electronic Health Records (EHRs) are needed. In this paper, we introduce such a process along side a standard-based architecture. It allows the modeling and implementation of EHRs in a lightweight Electronic Health Record System (EHRS) core. The approach is demonstrated and tested by a prototype implementation. The results show that the suggested approach is useful and facilitates the development of standardized EHRSs.
Computer modeling of electron and proton transport in chloroplasts.
Tikhonov, Alexander N; Vershubskii, Alexey V
2014-07-01
Photosynthesis is one of the most important biological processes in biosphere, which provides production of organic substances from atmospheric CO2 and water at expense of solar energy. In this review, we contemplate computer models of oxygenic photosynthesis in the context of feedback regulation of photosynthetic electron transport in chloroplasts, the energy-transducing organelles of the plant cell. We start with a brief overview of electron and proton transport processes in chloroplasts coupled to ATP synthesis and consider basic regulatory mechanisms of oxygenic photosynthesis. General approaches to computer simulation of photosynthetic processes are considered, including the random walk models of plastoquinone diffusion in thylakoid membranes and deterministic approach to modeling electron transport in chloroplasts based on the mass action law. Then we focus on a kinetic model of oxygenic photosynthesis that includes key stages of the linear electron transport, alternative pathways of electron transfer around photosystem I (PSI), transmembrane proton transport and ATP synthesis in chloroplasts. This model includes different regulatory processes: pH-dependent control of the intersystem electron transport, down-regulation of photosystem II (PSII) activity (non-photochemical quenching), the light-induced activation of the Bassham-Benson-Calvin (BBC) cycle. The model correctly describes pH-dependent feedback control of electron transport in chloroplasts and adequately reproduces a variety of experimental data on induction events observed under different experimental conditions in intact chloroplasts (variations of CO2 and O2 concentrations in atmosphere), including a complex kinetics of P700 (primary electron donor in PSI) photooxidation, CO2 consumption in the BBC cycle, and photorespiration. Finally, we describe diffusion-controlled photosynthetic processes in chloroplasts within the framework of the model that takes into account complex architecture of
Design and Modeling Billing solution to Next Generation Networks
Lakhtaria, Kamaljit I
2010-01-01
Next generation networks (NGN) services are assumed to be a new revenue stream for both network operators and service providers. New services especially focused on a mobile telecommunications that would be used not only as a communication de vice but also as a personal gateway to order or consume a variety of services and products [1]. This type of advanced services can be accomplished when the adaptability of the packet-networks (Internet) and the quality of service of the circuit switched networks are combined into one network [2]. New challenges appear in the billing of this heterogeneous multi services network. Some examples of such a services and possible solutions about charging and billing are examined in this paper. The first steps of mathematical model for billing are also considered.
A Model for an Electronic Information Marketplace
Directory of Open Access Journals (Sweden)
Wei Ge
2005-11-01
Full Text Available As the information content on the Internet increases, the task of locating desired information and assessing its quality becomes increasingly difficult. This development causes users to be more willing to pay for information that is focused on specific issues, verifiable, and available upon request. Thus, the nature of the Internet opens up the opportunity for information trading. In this context, the Internet cannot only be used to close the transaction, but also to deliver the product - desired information - to the user. Early attempts to implement such business models have fallen short of expectations. In this paper, we discuss the limitations of such practices and present a modified business model for information trading, which uses a reverse auction approach together with a multiple-buyer price discovery process
Electronic Warfare in Army Models - A Survey.
1980-08-01
Improvement Program (AMIP), Joint (Army, AF, Marines) EW Center, and SAGA (Studies, Analysis, and Gaming Agency) of the Joint Chiefs of Staff to identify an...Virginia, January, 1973. 5. Catalog of Wargaming and Military Simulation Models, 7th Edition, SAGA 180-77, Studies, Analysis, and Gaming Agency, Organization...snow/sleet. It can simulate nighttime with full moon and twilight , smoke and dust as they affect the target acquisition capability of an RPV-type device
Analysis of electronic models for solar cells including energy resolved defect densities
Energy Technology Data Exchange (ETDEWEB)
Glitzky, Annegret
2010-07-01
We introduce an electronic model for solar cells including energy resolved defect densities. The resulting drift-diffusion model corresponds to a generalized van Roosbroeck system with additional source terms coupled with ODEs containing space and energy as parameters for all defect densities. The system has to be considered in heterostructures and with mixed boundary conditions from device simulation. We give a weak formulation of the problem. If the boundary data and the sources are compatible with thermodynamic equilibrium the free energy along solutions decays monotonously. In other cases it may be increasing, but we estimate its growth. We establish boundedness and uniqueness results and prove the existence of a weak solution. This is done by considering a regularized problem, showing its solvability and the boundedness of its solutions independent of the regularization level. (orig.)
Directory of Open Access Journals (Sweden)
Mohamad Javad Kamali
2015-01-01
Full Text Available Thermodynamic modeling of surface tension of different electrolyte systems in presence of gas phase is studied. Using the solid-liquid equilibrium, Langmuir gas-solid adsorption, and ENRTL activity coefficient model, the surface tension of electrolyte solutions is calculated. The new model has two adjustable parameters which could be determined by fitting the experimental surface tension of binary aqueous electrolyte solution in single temperature. Then the values of surface tension for other temperatures in binary and ternary system of aqueous electrolyte solution are predicted. The average absolute deviations for calculation of surface tension of binary and mixed electrolyte systems by new model are 1.98 and 1.70%, respectively.
Kostanyan, Artak E
2015-08-07
In closed-loop recycling (CLR) chromatography, the effluent from the outlet of a column is directly returned into the column through the sample feed line and continuously recycled until the required separation is reached. To select optimal operating conditions for the separation of a given feed mixture, an appropriate mathematical description of the process is required. This work is concerned with the analysis of models for the CLR separations. Due to the effect of counteracting mechanisms on separation of solutes, analytical solutions of the models could be helpful to understand and optimize chromatographic processes. The objective of this work was to develop analytical expressions to describe the CLR counter-current (liquid-liquid) chromatography (CCC). The equilibrium dispersion and cell models were used to describe the transport and separation of solutes inside a CLR CCC column. The Laplace transformation is applied to solve the model equations. Several possible CLR chromatography methods for the binary and complex mixture separations are simulated.
Numerical solution of High-kappa model of superconductivity
Energy Technology Data Exchange (ETDEWEB)
Karamikhova, R. [Univ. of Texas, Arlington, TX (United States)
1996-12-31
We present formulation and finite element approximations of High-kappa model of superconductivity which is valid in the high {kappa}, high magnetic field setting and accounts for applied magnetic field and current. Major part of this work deals with steady-state and dynamic computational experiments which illustrate our theoretical results numerically. In our experiments we use Galerkin discretization in space along with Backward-Euler and Crank-Nicolson schemes in time. We show that for moderate values of {kappa}, steady states of the model system, computed using the High-kappa model, are virtually identical with results computed using the full Ginzburg-Landau (G-L) equations. We illustrate numerically optimal rates of convergence in space and time for the L{sup 2} and H{sup 1} norms of the error in the High-kappa solution. Finally, our numerical approximations demonstrate some well-known experimentally observed properties of high-temperature superconductors, such as appearance of vortices, effects of increasing the applied magnetic field and the sample size, and the effect of applied constant current.
a Procedural Solution to Model Roman Masonry Structures
Cappellini, V.; Saleri, R.; Stefani, C.; Nony, N.; De Luca, L.
2013-07-01
The paper will describe a new approach based on the development of a procedural modelling methodology for archaeological data representation. This is a custom-designed solution based on the recognition of the rules belonging to the construction methods used in roman times. We have conceived a tool for 3D reconstruction of masonry structures starting from photogrammetric surveying. Our protocol considers different steps. Firstly we have focused on the classification of opus based on the basic interconnections that can lead to a descriptive system used for their unequivocal identification and design. Secondly, we have chosen an automatic, accurate, flexible and open-source photogrammetric pipeline named Pastis Apero Micmac - PAM, developed by IGN (Paris). We have employed it to generate ortho-images from non-oriented images, using a user-friendly interface implemented by CNRS Marseille (France). Thirdly, the masonry elements are created in parametric and interactive way, and finally they are adapted to the photogrammetric data. The presented application, currently under construction, is developed with an open source programming language called Processing, useful for visual, animated or static, 2D or 3D, interactive creations. Using this computer language, a Java environment has been developed. Therefore, even if the procedural modelling reveals an accuracy level inferior to the one obtained by manual modelling (brick by brick), this method can be useful when taking into account the static evaluation on buildings (requiring quantitative aspects) and metric measures for restoration purposes.
Modelling Difficulties and Their Overcoming Strategies in the Solution of a Modelling Problem
Dede, Ayse Tekin
2016-01-01
The purpose of the study is to reveal the elementary mathematics student teachers' difficulties encountered in the solution of a modelling problem, the strategies to overcome those difficulties and whether the strategies worked or not. Nineteen student teachers solved the modelling problem in their four or five-person groups, and the video records…
Miyazako, Hiroki; Ishihara, Kazuhiko; Mabuchi, Kunihiko; Hoshino, Takayuki
2016-06-01
A method for in situ controlling the detachment and deposition of organic molecules such as sugars and biocompatible polymers in aqueous solutions by electron-beam (EB) scan is proposed and evaluated. It was demonstrated that EB irradiation could detach 2-methacryloyloxyethyl phosphorylcholine (MPC) polymers from a silicon nitride membrane. Moreover, organic molecules such as cationic polymers and sugars could be deposited on the membrane by EB irradiation. Spatial distributions of scattered electrons were numerically simulated, and acceleration voltage dependences of the detachment and deposition phenomena were experimentally measured. The simulations and experimental results suggest that the detachment of MPC polymers is mainly due to electrical effects of primary electrons, and that the deposition of organic molecules is mainly due to chemical reactions induced by primary electrons. In view of these findings, the proposed method can be applied to in situ and nanoscale patterning such as the fabrication of cell scaffolds.
Freezing point depression in model Lennard-Jones solutions
Koschke, Konstantin; Jörg Limbach, Hans; Kremer, Kurt; Donadio, Davide
2015-09-01
Crystallisation of liquid solutions is of uttermost importance in a wide variety of processes in materials, atmospheric and food science. Depending on the type and concentration of solutes the freezing point shifts, thus allowing control on the thermodynamics of complex fluids. Here we investigate the basic principles of solute-induced freezing point depression by computing the melting temperature of a Lennard-Jones fluid with low concentrations of solutes, by means of equilibrium molecular dynamics simulations. The effect of solvophilic and weakly solvophobic solutes at low concentrations is analysed, scanning systematically the size and the concentration. We identify the range of parameters that produce deviations from the linear dependence of the freezing point on the molal concentration of solutes, expected for ideal solutions. Our simulations allow us also to link the shifts in coexistence temperature to the microscopic structure of the solutions.
Mask process matching using a model based data preparation solution
Dillon, Brian; Saib, Mohamed; Figueiro, Thiago; Petroni, Paolo; Progler, Chris; Schiavone, Patrick
2015-10-01
Process matching is the ability to precisely reproduce the signature of a given fabrication process while using a different one. A process signature is typically described as systematic CD variation driven by feature geometry as a function of feature size, local density or distance to neighboring structures. The interest of performing process matching is usually to address differences in the mask fabrication process without altering the signature of the mask, which is already validated by OPC models and already used in production. The need for such process matching typically arises from the expansion of the production capacity within the same or different mask fabrication facilities, from the introduction of new, perhaps more advanced, equipment to deliver same process of record masks and/or from the re-alignment of processes which have altered over time. For state-of-the-art logic and memory mask processes, such matching requirements can be well below 2nm and are expected to reduce below 1nm in near future. In this paper, a data preparation solution for process matching is presented and discussed. Instead of adapting the physical process itself, a calibrated model is used to modify the data to be exposed by the source process in order to induce the results to match the one obtained while running the target process. This strategy consists in using the differences among measurements from the source and target processes, in the calibration of a single differential model. In this approach, no information other than the metrology results is required from either process. Experimental results were obtained by matching two different processes at Photronics. The standard deviation between both processes was of 2.4nm. After applying the process matching technique, the average absolute difference between the processes was reduced to 1.0nm with a standard deviation of 1.3nm. The methods used to achieve the result will be described along with implementation considerations, to
Ferromagnetism in Electronic Models for Manganites
Riera, Jose; Hallberg, Karen; Dagotto, Elbio
1996-01-01
Ground state properties of the Kondo model for manganese oxides in one dimension are studied using numerical techniques. The large Hund coupling ($J_{H}$) limit is specially analyzed. A robust region of fully saturated ferromagnetism (FM) is identified at all densities. For open boundary conditions it is shown exactly that the ground state is FM at $J_{H} = \\infty$. Hole-spin phase separation competing with FM was also observed when a large exchange $J$ between the $Mn^{3+}$ ions is used. As ...
Sun, Z H I; Xiao, Y; Sietsma, J; Agterhuis, H; Yang, Y
2016-11-01
Recovery of valuable metals from electronic waste has been highlighted by the EU directives. The difficulties for recycling are induced by the high complexity of such waste. In this research, copper could be selectively recovered using an ammonia-based process, from industrially processed information and communication technology (ICT) waste with high complexity. A detailed understanding on the role of ammonium salt was focused during both stages of leaching copper into a solution and the subsequent step for copper recovery from the solution. By comparing the reactivity of the leaching solution with different ammonium salts, their physiochemical behaviour as well as the leaching efficiency could be identified. The copper recovery rate could reach 95% with ammonium carbonate as the leaching salt. In the stage of copper recovery from the solution, electrodeposition was introduced without an additional solvent extraction step and the electrochemical behaviour of the solution was figured out. With a careful control of the electrodeposition conditions, the current efficiency could be improved to be 80-90% depending on the ammonia salts and high purity copper (99.9wt.%). This research provides basis for improving the recyclability and efficiency of copper recovery from such electronic waste and the whole process design for copper recycling.
Energy Technology Data Exchange (ETDEWEB)
Audette-Stuart, Marilyne [Atomic Energy of Canada Limited, CANDU Life Sciences Center, Chalk River Laboratories, Chalk River Ont., K0J 1J0 (Canada); Houee-Levin, Chantal [Laboratoire de Chimie Physique, UMR-8000 CNRS-Universite Paris XI, Centre Universitaire, F-91405 Orsay Cedex (France)]. E-mail: chantal.houee-levin@lcp.u-psud.fr; Potier, Michel [Service de genetique medicale, Hopital Sainte-Justine, Universite de Montreal, Montreal Que., H3 T 1C5 (Canada)
2005-02-01
Irradiation of proteins in diluted liquid aqueous solutions produces cleavages and polymerizations of the peptidic chains. In frozen solutions, fragmentation is observed but polymerization products are absent. Loss of activity occurs in both cases. In the solid state, yields of fragmentation do not vary with the quantity of water. The use of scavengers indicates that hydroxyl radical does not contribute significantly to fragmentation and to inactivation in the solid state. Electrons within the water molecules closely associated with the protein are involved in the processes leading to protein fragmentation.
Chen, Duan; Wei, Guo-Wei
2010-01-01
The miniaturization of nano-scale electronic devices, such as metal oxide semiconductor field effect transistors (MOSFETs), has given rise to a pressing demand in the new theoretical understanding and practical tactic for dealing with quantum mechanical effects in integrated circuits. Modeling and simulation of this class of problems have emerged as an important topic in applied and computational mathematics. This work presents mathematical models and computational algorithms for the simulation of nano-scale MOSFETs. We introduce a unified two-scale energy functional to describe the electrons and the continuum electrostatic potential of the nano-electronic device. This framework enables us to put microscopic and macroscopic descriptions in an equal footing at nano scale. By optimization of the energy functional, we derive consistently-coupled Poisson-Kohn-Sham equations. Additionally, layered structures are crucial to the electrostatic and transport properties of nano transistors. A material interface model is proposed for more accurate description of the electrostatics governed by the Poisson equation. Finally, a new individual dopant model that utilizes the Dirac delta function is proposed to understand the random doping effect in nano electronic devices. Two mathematical algorithms, the matched interface and boundary (MIB) method and the Dirichlet-to-Neumann mapping (DNM) technique, are introduced to improve the computational efficiency of nano-device simulations. Electronic structures are computed via subband decomposition and the transport properties, such as the I-V curves and electron density, are evaluated via the non-equilibrium Green's functions (NEGF) formalism. Two distinct device configurations, a double-gate MOSFET and a four-gate MOSFET, are considered in our three-dimensional numerical simulations. For these devices, the current fluctuation and voltage threshold lowering effect induced by the discrete dopant model are explored. Numerical convergence
Chen, Duan; Wei, Guo-Wei
2010-06-01
The miniaturization of nano-scale electronic devices, such as metal oxide semiconductor field effect transistors (MOSFETs), has given rise to a pressing demand in the new theoretical understanding and practical tactic for dealing with quantum mechanical effects in integrated circuits. Modeling and simulation of this class of problems have emerged as an important topic in applied and computational mathematics. This work presents mathematical models and computational algorithms for the simulation of nano-scale MOSFETs. We introduce a unified two-scale energy functional to describe the electrons and the continuum electrostatic potential of the nano-electronic device. This framework enables us to put microscopic and macroscopic descriptions in an equal footing at nano-scale. By optimization of the energy functional, we derive consistently coupled Poisson-Kohn-Sham equations. Additionally, layered structures are crucial to the electrostatic and transport properties of nano-transistors. A material interface model is proposed for more accurate description of the electrostatics governed by the Poisson equation. Finally, a new individual dopant model that utilizes the Dirac delta function is proposed to understand the random doping effect in nano-electronic devices. Two mathematical algorithms, the matched interface and boundary (MIB) method and the Dirichlet-to-Neumann mapping (DNM) technique, are introduced to improve the computational efficiency of nano-device simulations. Electronic structures are computed via subband decomposition and the transport properties, such as the I- V curves and electron density, are evaluated via the non-equilibrium Green's functions (NEGF) formalism. Two distinct device configurations, a double-gate MOSFET and a four-gate MOSFET, are considered in our three-dimensional numerical simulations. For these devices, the current fluctuation and voltage threshold lowering effect induced by the discrete dopant model are explored. Numerical
Institute of Scientific and Technical Information of China (English)
黎勇; 陈丽
2002-01-01
In this paper, we study the asymptotic behavior of global smooth solution to the initial boundary problem for the 1-D energy transport model in semiconductor science. We prove that the smooth solution of the problem converges to a stationary solution exponentially fast as t - ∞ when the initial data is a small perturbation of the stationary solution.
Lei, Hongwei; Yang, Guang; Guo, Yaxiong; Xiong, Liangbin; Qin, Pingli; Dai, Xin; Zheng, Xiaolu; Ke, Weijun; Tao, Hong; Chen, Zhao; Li, Borui; Fang, Guojia
2016-06-28
Efficient planar antimony sulfide (Sb2S3) heterojunction solar cells have been made using chemical bath deposited (CBD) Sb2S3 as the absorber, low-temperature solution-processed tin oxide (SnO2) as the electron conductor and poly (3-hexylthiophene) (P3HT) as the hole conductor. A solar conversion efficiency of 2.8% was obtained at 1 sun illumination using a planar device consisting of F-doped SnO2 substrate/SnO2/CBD-Sb2S3/P3HT/Au, whereas the solar cells based on a titanium dioxide (TiO2) electron conductor exhibited a power conversion efficiency of 1.9%. Compared with conventional Sb2S3 sensitized solar cells, the high-temperature processed mesoscopic TiO2 scaffold is no longer needed. More importantly, a low-temperature solution-processed SnO2 layer was introduced for electron transportation to substitute the high-temperature sintered dense blocking TiO2 layer. Our planar solar cells not only have simple geometry with fewer steps to fabricate but also show enhanced performance. The higher efficiency of planar Sb2S3 solar cell devices based on a SnO2 electron conductor is attributed to their high transparency, uniform surface, efficient electron transport properties of SnO2, suitable energy band alignment, and reduced recombination at the interface of SnO2/Sb2S3.
Itoh-Watanabe, Hikari; Kamihira-Ishijima, Miya; Kawamura, Izuru; Kondoh, Masashi; Nakakoshi, Masamichi; Sato, Michio; Naito, Akira
2013-10-21
Human calcitonin (hCT) is a 32-amino acid peptide hormone that contains an intrachain disulfide bridge between Cys1 and Cys7 and a proline amide at the C-terminus. hCT tends to associate to form a fibril precipitate of the same type as amyloid fibrils, and hence has been studied as a model of amyloid fibril formation. The fibrillation process in N-(2-hydroxyethyl)piperazine-N'-2-ethanesulfonic acid (HEPES) solution was examined using transmission electron microscopy. The rate of hCT fibrillation in HEPES solution was much lower than in phosphate buffer and acetic acid solution. Spherical intermediate aggregates (nuclei) were observed during the early stage of fibril formation. Short proto-fibrils appeared on the surface of the spherical intermediates. Subsequently, the spherical intermediates transformed directly into long proto-fibrils, which then elongated into mature hCT fibrils. The fibrillation process was also examined using solid-state (13)C-NMR spectroscopy, which indicated that the fibril structure was a β-sheet in the central region and a mixture of random coils and β-sheets at the C-terminus. The kinetics of fibril formation was examined in terms of a two-step autocatalytic reaction mechanism. The first-step nucleation rate (k1) was lower in HEPES solution than in phosphate buffer and acetic acid solution because the half-life of the intermediates is significantly longer in HEPES solution. In contrast, the second-step fibril elongation rate (k2) was similar in HEPES solution and acidic solutions. Specific interaction of HEPES molecules with hCT may stabilize the spherical intermediates and consequently inhibit the fibril elongation process of hCT.
Modeling the customer in electronic commerce.
Helander, M G; Khalid, H M
2000-12-01
This paper reviews interface design of web pages for e-commerce. Different tasks in e-commerce are contrasted. A systems model is used to illustrate the information flow between three subsystems in e-commerce: store environment, customer, and web technology. A customer makes several decisions: to enter the store, to navigate, to purchase, to pay, and to keep the merchandize. This artificial environment must be designed so that it can support customer decision-making. To retain customers it must be pleasing and fun, and create a task with natural flow. Customers have different needs, competence and motivation, which affect decision-making. It may therefore be important to customize the design of the e-store environment. Future ergonomics research will have to investigate perceptual aspects, such as presentation of merchandize, and cognitive issues, such as product search and navigation, as well as decision making while considering various economic parameters. Five theories on e-commerce research are presented.
Numerical modeling of electron-beam welding of dissimilar metals
Krektuleva, R. A.; Cherepanov, O. I.; Cherepanov, R. O.
2016-11-01
This paper is devoted to numerical modeling of heat transfer processes and estimation of thermal stresses in weld seams created by electron beam welding of heterogeneous metals. The mathematical model is based on a system of equations that includes the Lagrange's variational equation of theory of plasticity and variational equation of M. Biot's principle to simulate the heat transfer processes. The two-dimensional problems (plane strain and plane stress) are considered for estimation of thermal stresses in welds considering differences of mechanical properties of welded materials. The model is developed for simulation of temperature fields and stresses during electron beam welding.
Modified binary encounter Bethe model for electron-impact ionization
Guerra, M; Indelicato, P; Santos, J P
2013-01-01
Theoretical expressions for ionization cross sections by electron impact based on the binary encounter Bethe (BEB) model, valid from ionization threshold up to relativistic energies, are proposed. The new modified BEB (MBEB) and its relativistic counterpart (MRBEB) expressions are simpler than the BEB (nonrelativistic and relativistic) expressions because they require only one atomic parameter, namely the binding energy of the electrons to be ionized, and use only one scaling term for the ionization of all sub-shells. The new models are used to calculate the K-, L- and M-shell ionization cross sections by electron impact for several atoms with Z from 6 to 83. Comparisons with all, to the best of our knowledge, available experimental data show that this model is as good or better than other models, with less complexity.
Relativistic models for quasielastic electron and neutrino-nucleus scattering
Directory of Open Access Journals (Sweden)
Meucci Andrea
2012-12-01
Full Text Available Relativistic models developed within the framework of the impulse approximation for quasielastic (QE electron scattering and successfully tested in comparison with electron-scattering data have been extended to neutrino-nucleus scattering. Different descriptions of final-state interactions (FSI in the inclusive scattering are compared. In the relativistic Green’s function (RGF model FSI are described consistently with the exclusive scattering using a complex optical potential. In the relativistic mean field (RMF model FSI are described by the same RMF potential which gives the bound states. The results of the models are compared for electron and neutrino scattering and, for neutrino scattering, with the recently measured charged-current QE (CCQE MiniBooNE cross sections.
Electron spin relaxation of copper(II) complexes in glassy solution between 10 and 120 K.
Fielding, Alistair J; Fox, Stephen; Millhauser, Glenn L; Chattopadhyay, Madhuri; Kroneck, Peter M H; Fritz, Günter; Eaton, Gareth R; Eaton, Sandra S
2006-03-01
The temperature dependence, between 10 and 120 K, of electron spin-lattice relaxation at X-band was analyzed for a series of eight pyrrolate-imine complexes and for ten other copper(II) complexes with varying ligands and geometry including copper-containing prion octarepeat domain and S100 type proteins. The geometry of the CuN4 coordination sphere for pyrrolate-imine complexes with R=H, methyl, n-butyl, diphenylmethyl, benzyl, 2-adamantyl, 1-adamantyl, and tert-butyl has been shown to range from planar to pseudo-tetrahedral. The fit to the recovery curves was better for a distribution of values of T1 than for a single time constant. Distributions of relaxation times may be characteristic of Cu(II) in glassy solution. Long-pulse saturation recovery and inversion recovery measurements were performed. The temperature dependence of spin-lattice relaxation rates was analyzed in terms of contributions from the direct process, the Raman process, and local modes. It was necessary to include more than one process to fit the experimental data. There was a small contribution from the direct process at low temperature. The Raman process was the dominant contribution to relaxation between about 20 and 60 K. Debye temperatures were between 80 and 120 K. For samples with similar Debye temperatures the coefficient of the Raman process tended to increase as gz increased, as expected if modulation of spin-orbit coupling is a major factor in relaxation rates. Above about 60 K local modes with energies in the range of 260-360 K (180-250 cm-1) dominated the relaxation. For molecules with similar geometry, relaxation rates were faster for more flexible molecules than for more rigid ones. Relaxation rates for the copper protein samples were similar to rates for small molecules with comparable coordination spheres. At each temperature studied the range of relaxation rates was less than an order of magnitude. The spread was smaller between 20 and 60 K where the Raman process dominates
A conceptual model for assessing the impact of electronic procurement
Boer, de Luitzen; Harink, Jeroen; Heijboer, Govert
2002-01-01
This paper aims to contribute to the development of a conceptual model for studying the direct and indirect impact of various forms of electronic procurement (EP) on a firm's integral purchasing (-related) costs. The model builds on existing classifications of purchasing-related costs and benefits a
Modeling paraxial wave propagation in free-electron laser oscillators
Karssenberg, J.G.; van der Slot, Petrus J.M.; Volokhine, I.; Verschuur, Jeroen W.J.; Boller, Klaus J.
2006-01-01
Modeling free-electron laser (FEL) oscillators requires calculation of both the light-beam interaction within the undulator and the light propagation outside the undulator. We have developed a paraxial optical propagation code that can be combined with various existing models of gain media, for
Modeling paraxial wave propagation in free-electron laser oscillators
Karssenberg, J.G.; Slot, van der P.J.M.; Volokhine, I.V.; Verschuur, J.W.J.; Boller, K.J.
2006-01-01
Modeling free-electron laser (FEL) oscillators requires calculation of both the light-beam interaction within the undulator and the light propagation outside the undulator. We have developed a paraxial optical propagation code that can be combined with various existing models of gain media, for exam
Directory of Open Access Journals (Sweden)
Bennaceur-Doumaz Djamila
2016-06-01
Full Text Available The expansion of semi-infinite laser produced plasma into vacuum is analyzed with a hydrodynamic model for cold ions assuming electrons modeled by a kappa-type distribution. Self-similar analytic expressions for the potential, velocity, and density of the plasma have been derived. It is shown that nonthermal energetic electrons have the role of accelerating the self-similar expansion.
Density-dependent electron transport and precise modeling of GaN high electron mobility transistors
Energy Technology Data Exchange (ETDEWEB)
Bajaj, Sanyam, E-mail: bajaj.10@osu.edu; Shoron, Omor F.; Park, Pil Sung; Krishnamoorthy, Sriram; Akyol, Fatih; Hung, Ting-Hsiang [Department of Electrical and Computer Engineering, The Ohio State University, Columbus, Ohio 43210 (United States); Reza, Shahed; Chumbes, Eduardo M. [Raytheon Integrated Defense Systems, Andover, Massachusetts 01810 (United States); Khurgin, Jacob [Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, Maryland 21218 (United States); Rajan, Siddharth [Department of Electrical and Computer Engineering, The Ohio State University, Columbus, Ohio 43210 (United States); Department of Material Science and Engineering, The Ohio State University, Columbus, Ohio 43210 (United States)
2015-10-12
We report on the direct measurement of two-dimensional sheet charge density dependence of electron transport in AlGaN/GaN high electron mobility transistors (HEMTs). Pulsed IV measurements established increasing electron velocities with decreasing sheet charge densities, resulting in saturation velocity of 1.9 × 10{sup 7 }cm/s at a low sheet charge density of 7.8 × 10{sup 11 }cm{sup −2}. An optical phonon emission-based electron velocity model for GaN is also presented. It accommodates stimulated longitudinal optical (LO) phonon emission which clamps the electron velocity with strong electron-phonon interaction and long LO phonon lifetime in GaN. A comparison with the measured density-dependent saturation velocity shows that it captures the dependence rather well. Finally, the experimental result is applied in TCAD-based device simulator to predict DC and small signal characteristics of a reported GaN HEMT. Good agreement between the simulated and reported experimental results validated the measurement presented in this report and established accurate modeling of GaN HEMTs.
Kinetic modelling of runaway electrons in dynamic scenarios
Stahl, A; Papp, G; Landreman, M; Fülöp, T
2016-01-01
Improved understanding of runaway-electron formation and decay processes are of prime interest for the safe operation of large tokamaks, and the dynamics of the runaway electrons during dynamical scenarios such as disruptions are of particular concern. In this paper, we present kinetic modelling of scenarios with time-dependent plasma parameters; in particular, we investigate hot-tail runaway generation during a rapid drop in plasma temperature. With the goal of studying runaway-electron generation with a self-consistent electric-field evolution, we also discuss the implementation of a conservative collision operator and demonstrate its properties. An operator for avalanche runaway-electron generation, which takes the energy dependence of the scattering cross section and the runaway distribution into account, is investigated. We show that the simpler avalanche model of Rosenbluth & Putvinskii [Nucl. Fusion 37, 1355 (1997)] can give very inaccurate results for the avalanche growth rate (either lower or hig...
New analytic solutions for modeling vertical gravity gradient anomalies
Kim, Seung-Sep; Wessel, Paul
2016-05-01
Modern processing of satellite altimetry for use in marine gravimetry involves computing the along-track slopes of observed sea-surface heights, projecting them into east-west and north-south deflection of the vertical grids, and using Laplace's equation to algebraically obtain a grid of the vertical gravity gradient (VGG). The VGG grid is then integrated via overlapping, flat Earth Fourier transforms to yield a free-air anomaly grid. Because of this integration and associated edge effects, the VGG grid retains more short-wavelength information (e.g., fracture zone and seamount signatures) that is of particular importance for plate tectonic investigations. While modeling of gravity anomalies over arbitrary bodies has long been a standard undertaking, similar modeling of VGG anomalies over oceanic features is not commonplace yet. Here we derive analytic solutions for VGG anomalies over simple bodies and arbitrary 2-D and 3-D sources. We demonstrate their usability in determining mass excess and deficiency across the Mendocino fracture zone (a 2-D feature) and find the best bulk density estimate for Jasper seamount (a 3-D feature). The methodologies used herein are implemented in the Generic Mapping Tools, available from gmt.soest.hawaii.edu.
Fluid of fused spheres as a model for protein solution
Directory of Open Access Journals (Sweden)
M. Kastelic
2016-03-01
Full Text Available In this work we examine thermodynamics of fluid with "molecules" represented by two fused hard spheres, decorated by the attractive square-well sites. Interactions between these sites are of short-range and cause association between the fused-sphere particles. The model can be used to study the non-spherical (or dimerized proteins in solution. Thermodynamic quantities of the system are calculated using a modification of Wertheim's thermodynamic perturbation theory and the results compared with new Monte Carlo simulations under isobaric-isothermal conditions. In particular, we are interested in the liquid-liquid phase separation in such systems. The model fluid serves to evaluate the effect of the shape of the molecules, changing from spherical to more elongated (two fused spheres ones. The results indicate that the effect of the non-spherical shape is to reduce the critical density and temperature. This finding is consistent with experimental observations for the antibodies of non-spherical shape.
Eigenvalue solution to the electron-collisional effect on ion-acoustic and entropy waves
Institute of Scientific and Technical Information of China (English)
无
2001-01-01
The linearized electron Fokker-Planck and cold-ion fluid equations are solved as an eigenvalue problem in the quasineutral limit for ionization state,Z=1,8,and 64 for ion-acoustic and entropy waves.The perturbed electron distribution function is written as a moment expansion of eigenvectors,and is used to compute collisionality-dependence macroscopic quantities in the plasma such as the generalized specific heat ratio,and the electron thermal conductivity.
Modeling electron fractionalization with unconventional Fock spaces
Cobanera, Emilio
2017-08-01
It is shown that certain fractionally-charged quasiparticles can be modeled on D-dimensional lattices in terms of unconventional yet simple Fock algebras of creation and annihilation operators. These unconventional Fock algebras are derived from the usual fermionic algebra by taking roots (the square root, cubic root, etc) of the usual fermionic creation and annihilation operators. If the fermions carry non-Abelian charges, then this approach fractionalizes the Abelian charges only. In particular, the mth-root of a spinful fermion carries charge e/m and spin 1/2. Just like taking a root of a complex number, taking a root of a fermion yields a mildly non-unique result. As a consequence, there are several possible choices of quantum exchange statistics for fermion-root quasiparticles. These choices are tied to the dimensionality D=1,2,3,\\ldots of the lattice by basic physical considerations. One particular family of fermion-root quasiparticles is directly connected to the parafermion zero-energy modes expected to emerge in certain mesoscopic devices involving fractional quantum Hall states. Hence, as an application of potential mesoscopic interest, I investigate numerically the hybridization of Majorana and parafermion zero-energy edge modes caused by fractionalizing but charge-conserving tunneling.
USign--a security enhanced electronic consent model.
Li, Yanyan; Xie, Mengjun; Bian, Jiang
2014-01-01
Electronic consent becomes increasingly popular in the healthcare sector given the many benefits it provides. However, security concerns, e.g., how to verify the identity of a person who is remotely accessing the electronic consent system in a secure and user-friendly manner, also arise along with the popularity of electronic consent. Unfortunately, existing electronic consent systems do not pay sufficient attention to those issues. They mainly rely on conventional password based authentication to verify the identity of an electronic consent user, which is far from being sufficient given that identity theft threat is real and significant in reality. In this paper, we present a security enhanced electronic consent model called USign. USign enhances the identity protection and authentication for electronic consent systems by leveraging handwritten signatures everyone is familiar with and mobile computing technologies that are becoming ubiquitous. We developed a prototype of USign and conducted preliminary evaluation on accuracy and usability of signature verification. Our experimental results show the feasibility of the proposed model.
Molecular modeling of inelastic electron transport in molecular junctions
Jiang, Jun; Kula, Mathias; Luo, Yi
2008-09-01
A quantum chemical approach for the modeling of inelastic electron tunneling spectroscopy of molecular junctions based on scattering theory is presented. Within a harmonic approximation, the proposed method allows us to calculate the electron-vibration coupling strength analytically, which makes it applicable to many different systems. The calculated inelastic electron transport spectra are often in very good agreement with their experimental counterparts, allowing the revelation of detailed information about molecular conformations inside the junction, molecule-metal contact structures, and intermolecular interaction that is largely inaccessible experimentally.
Molecular modeling of inelastic electron transport in molecular junctions
Energy Technology Data Exchange (ETDEWEB)
Jiang Jun; Kula, Mathias; Luo Yi [Department of Theoretical Chemistry, School of Biotechnology, Royal Institute of Technology, S-106 91 Stockholm (Sweden)], E-mail: luo@kth.se
2008-09-17
A quantum chemical approach for the modeling of inelastic electron tunneling spectroscopy of molecular junctions based on scattering theory is presented. Within a harmonic approximation, the proposed method allows us to calculate the electron-vibration coupling strength analytically, which makes it applicable to many different systems. The calculated inelastic electron transport spectra are often in very good agreement with their experimental counterparts, allowing the revelation of detailed information about molecular conformations inside the junction, molecule-metal contact structures, and intermolecular interaction that is largely inaccessible experimentally.
Ionospheric topside models compared with experimental electron density profiles
Directory of Open Access Journals (Sweden)
S. M. Radicella
2005-06-01
Full Text Available Recently an increasing number of topside electron density profiles has been made available to the scientific community on the Internet. These data are important for ionospheric modeling purposes, since the experimental information on the electron density above the ionosphere maximum of ionization is very scarce. The present work compares NeQuick and IRI models with the topside electron density profiles available in the databases of the ISIS2, IK19 and Cosmos 1809 satellites. Experimental electron content from the F2 peak up to satellite height and electron densities at fixed heights above the peak have been compared under a wide range of different conditions. The analysis performed points out the behavior of the models and the improvements needed to be assessed to have a better reproduction of the experimental results. NeQuick topside is a modified Epstein layer, with thickness parameter determined by an empirical relation. It appears that its performance is strongly affected by this parameter, indicating the need for improvements of its formulation. IRI topside is based on Booker's approach to consider two parts with constant height gradients. It appears that this formulation leads to an overestimation of the electron density in the upper part of the profiles, and overestimation of TEC.
Institute of Scientific and Technical Information of China (English)
CAI Liang; ZHANG Ping; YANG Tao; PAN Xiao-Yin
2011-01-01
By using the path integral approach, we investigate the problem of Hooke's atom (two electrons interacting with Coulomb potential in an external harmonic-oscillator potential) in an arbitrary time-dependent electric field. For a certain infinite set of discrete oscillator frequencies, we obtain the analytical solutions. The ground state polarization of the atom is then calculated. The same result is also obtained through linear response theory.
Computational model for simulation small testing launcher, technical solution
Energy Technology Data Exchange (ETDEWEB)
Chelaru, Teodor-Viorel, E-mail: teodor.chelaru@upb.ro [University POLITEHNICA of Bucharest - Research Center for Aeronautics and Space, Str. Ghe Polizu, nr. 1, Bucharest, Sector 1 (Romania); Cristian, Barbu, E-mail: barbucr@mta.ro [Military Technical Academy, Romania, B-dul. George Coşbuc, nr. 81-83, Bucharest, Sector 5 (Romania); Chelaru, Adrian, E-mail: achelaru@incas.ro [INCAS -National Institute for Aerospace Research Elie Carafoli, B-dul Iuliu Maniu 220, 061126, Bucharest, Sector 6 (Romania)
2014-12-10
The purpose of this paper is to present some aspects regarding the computational model and technical solutions for multistage suborbital launcher for testing (SLT) used to test spatial equipment and scientific measurements. The computational model consists in numerical simulation of SLT evolution for different start conditions. The launcher model presented will be with six degrees of freedom (6DOF) and variable mass. The results analysed will be the flight parameters and ballistic performances. The discussions area will focus around the technical possibility to realize a small multi-stage launcher, by recycling military rocket motors. From technical point of view, the paper is focused on national project 'Suborbital Launcher for Testing' (SLT), which is based on hybrid propulsion and control systems, obtained through an original design. Therefore, while classical suborbital sounding rockets are unguided and they use as propulsion solid fuel motor having an uncontrolled ballistic flight, SLT project is introducing a different approach, by proposing the creation of a guided suborbital launcher, which is basically a satellite launcher at a smaller scale, containing its main subsystems. This is why the project itself can be considered an intermediary step in the development of a wider range of launching systems based on hybrid propulsion technology, which may have a major impact in the future European launchers programs. SLT project, as it is shown in the title, has two major objectives: first, a short term objective, which consists in obtaining a suborbital launching system which will be able to go into service in a predictable period of time, and a long term objective that consists in the development and testing of some unconventional sub-systems which will be integrated later in the satellite launcher as a part of the European space program. This is why the technical content of the project must be carried out beyond the range of the existing suborbital
A Physical Model of Electron Radiation Belts of Saturn
Lorenzato, L.; Sicard-Piet, A.; Bourdarie, S.
2012-04-01
Radiation belts causes irreversible damages on on-board instruments materials. That's why for two decades, ONERA proposes studies about radiation belts of magnetized planets. First, in the 90's, the development of a physical model, named Salammbô, carried out a model of the radiation belts of the Earth. Then, for few years, analysis of the magnetosphere of Jupiter and in-situ data (Pioneer, Voyager, Galileo) allow to build a physical model of the radiation belts of Jupiter. Enrolling on the Cassini age and thanks to all information collected, this study permits to adapt Salammbô jovian radiation belts model to the case of Saturn environment. Indeed, some physical processes present in the kronian magnetosphere are similar to those present in the magnetosphere of Jupiter (radial diffusion; interaction of energetic electrons with rings, moons, atmosphere; synchrotron emission). However, some physical processes have to be added to the kronian model (compared to the jovian model) because of the particularity of the magnetosphere of Saturn: interaction of energetic electrons with neutral particles from Enceladus, and wave-particle interaction. This last physical process has been studied in details with the analysis of CASSINI/RPWS (Radio and Plasma Waves Science) data. The major importance of the wave particles interaction is now well known in the case of the radiation belts of the Earth but it is important to investigate on its role in the case of Saturn. So, importance of each physical process has been studied and analysis of Cassini MIMI-LEMMS and CAPS data allows to build a model boundary condition (at L = 6). Finally, results of this study lead to a kronian electrons radiation belts model including radial diffusion, interactions of energetic electrons with rings, moons and neutrals particles and wave-particle interaction (interactions of electrons with atmosphere particles and synchrotron emission are too weak to be taken into account in this model). Then, to
A deterministic partial differential equation model for dose calculation in electron radiotherapy
Energy Technology Data Exchange (ETDEWEB)
Duclous, R; Dubroca, B [CELIA and IMB Laboratories, Bordeaux University, 33405 Talence (France); Frank, M, E-mail: duclous@celia.u-bordeaux1.f, E-mail: dubroca@celia.u-bordeaux1.f, E-mail: frank@mathcces.rwth-aachen.d [Department of Mathematics and Center for Computational Engineering Science, RWTH Aachen University, Schinkelstr. 2, 52062 Aachen (Germany)
2010-07-07
High-energy ionizing radiation is a prominent modality for the treatment of many cancers. The approaches to electron dose calculation can be categorized into semi-empirical models (e.g. Fermi-Eyges, convolution-superposition) and probabilistic methods (e.g. Monte Carlo). A third approach to dose calculation has only recently attracted attention in the medical physics community. This approach is based on the deterministic kinetic equations of radiative transfer. We derive a macroscopic partial differential equation model for electron transport in tissue. This model involves an angular closure in the phase space. It is exact for the free streaming and the isotropic regime. We solve it numerically by a newly developed HLLC scheme based on Berthon et al (2007 J. Sci. Comput. 31 347-89) that exactly preserves the key properties of the analytical solution on the discrete level. We discuss several test cases taken from the medical physics literature. A test case with an academic Henyey-Greenstein scattering kernel is considered. We compare our model to a benchmark discrete ordinate solution. A simplified model of electron interactions with tissue is employed to compute the dose of an electron beam in a water phantom, and a case of irradiation of the vertebral column. Here our model is compared to the PENELOPE Monte Carlo code. In the academic example, the fluences computed with the new model and a benchmark result differ by less than 1%. The depths at half maximum differ by less than 0.6%. In the two comparisons with Monte Carlo, our model gives qualitatively reasonable dose distributions. Due to the crude interaction model, these so far do not have the accuracy needed in clinical practice. However, the new model has a computational cost that is less than one-tenth of the cost of a Monte Carlo simulation. In addition, simulations can be set up in a similar way as a Monte Carlo simulation. If more detailed effects such as coupled electron-photon transport, bremsstrahlung
A deterministic partial differential equation model for dose calculation in electron radiotherapy
Duclous, R.; Dubroca, B.; Frank, M.
2010-07-01
High-energy ionizing radiation is a prominent modality for the treatment of many cancers. The approaches to electron dose calculation can be categorized into semi-empirical models (e.g. Fermi-Eyges, convolution-superposition) and probabilistic methods (e.g. Monte Carlo). A third approach to dose calculation has only recently attracted attention in the medical physics community. This approach is based on the deterministic kinetic equations of radiative transfer. We derive a macroscopic partial differential equation model for electron transport in tissue. This model involves an angular closure in the phase space. It is exact for the free streaming and the isotropic regime. We solve it numerically by a newly developed HLLC scheme based on Berthon et al (2007 J. Sci. Comput. 31 347-89) that exactly preserves the key properties of the analytical solution on the discrete level. We discuss several test cases taken from the medical physics literature. A test case with an academic Henyey-Greenstein scattering kernel is considered. We compare our model to a benchmark discrete ordinate solution. A simplified model of electron interactions with tissue is employed to compute the dose of an electron beam in a water phantom, and a case of irradiation of the vertebral column. Here our model is compared to the PENELOPE Monte Carlo code. In the academic example, the fluences computed with the new model and a benchmark result differ by less than 1%. The depths at half maximum differ by less than 0.6%. In the two comparisons with Monte Carlo, our model gives qualitatively reasonable dose distributions. Due to the crude interaction model, these so far do not have the accuracy needed in clinical practice. However, the new model has a computational cost that is less than one-tenth of the cost of a Monte Carlo simulation. In addition, simulations can be set up in a similar way as a Monte Carlo simulation. If more detailed effects such as coupled electron-photon transport, bremsstrahlung
The perturbed solution of sea-air oscillator for ENSO model
Institute of Scientific and Technical Information of China (English)
MO Jiaqi; LIN Wantao; ZHU Jiang
2004-01-01
A class of delayed oscillators and coupled systems to oscillation of El Nino-Southern Oscillation (ENSO) models are considered. Using the perturbed theory and other methods, the exact solution or asymptotic expansions of the solution for ENSO models is obtained and the asymptotic behavior of solution of corresponding problem is studied.
Directory of Open Access Journals (Sweden)
Hao Yu
2016-12-01
Full Text Available Today, the increased public concern about sustainable development and more stringent environmental regulations have become important driving forces for value recovery from end-of-life and end-of use products through reverse logistics. Waste electrical and electronic equipment (WEEE contains both valuable components that need to be recycled and hazardous substances that have to be properly treated or disposed of, so the design of a reverse logistics system for sustainable treatment of WEEE is of paramount importance. This paper presents a stochastic mixed integer programming model for designing and planning a generic multi-source, multi-echelon, capacitated, and sustainable reverse logistics network for WEEE management under uncertainty. The model takes into account both economic efficiency and environmental impacts in decision-making, and the environmental impacts are evaluated in terms of carbon emissions. A multi-criteria two-stage scenario-based solution method is employed and further developed in this study for generating the optimal solution for the stochastic optimization problem. The proposed model and solution method are validated through a numerical experiment and sensitivity analyses presented later in this paper, and an analysis of the results is also given to provide a deep managerial insight into the application of the proposed stochastic optimization model.
Understanding quantum measurement from the solution of dynamical models
Energy Technology Data Exchange (ETDEWEB)
Allahverdyan, Armen E. [Laboratoire de Physique Statistique et Systèmes Complexes, ISMANS, 44 Av. Bartholdi, 72000 Le Mans (France); Balian, Roger [Institut de Physique Théorique, CEA Saclay, 91191 Gif-sur-Yvette cedex (France); Nieuwenhuizen, Theo M., E-mail: T.M.Nieuwenhuizen@uva.nl [Center for Cosmology and Particle Physics, New York University, 4 Washington Place, New York, NY 10003 (United States)
2013-04-15
The quantum measurement problem, to wit, understanding why a unique outcome is obtained in each individual experiment, is currently tackled by solving models. After an introduction we review the many dynamical models proposed over the years for elucidating quantum measurements. The approaches range from standard quantum theory, relying for instance on quantum statistical mechanics or on decoherence, to quantum–classical methods, to consistent histories and to modifications of the theory. Next, a flexible and rather realistic quantum model is introduced, describing the measurement of the z-component of a spin through interaction with a magnetic memory simulated by a Curie–Weiss magnet, including N≫1 spins weakly coupled to a phonon bath. Initially prepared in a metastable paramagnetic state, it may transit to its up or down ferromagnetic state, triggered by its coupling with the tested spin, so that its magnetization acts as a pointer. A detailed solution of the dynamical equations is worked out, exhibiting several time scales. Conditions on the parameters of the model are found, which ensure that the process satisfies all the features of ideal measurements. Various imperfections of the measurement are discussed, as well as attempts of incompatible measurements. The first steps consist in the solution of the Hamiltonian dynamics for the spin-apparatus density matrix D{sup -hat} (t). Its off-diagonal blocks in a basis selected by the spin–pointer coupling, rapidly decay owing to the many degrees of freedom of the pointer. Recurrences are ruled out either by some randomness of that coupling, or by the interaction with the bath. On a longer time scale, the trend towards equilibrium of the magnet produces a final state D{sup -hat} (t{sub f}) that involves correlations between the system and the indications of the pointer, thus ensuring registration. Although D{sup -hat} (t{sub f}) has the form expected for ideal measurements, it only describes a large set of
An extended model for electron spin polarization in photosynthetic bacteria
Energy Technology Data Exchange (ETDEWEB)
Morris, A.L.; Norris, J.R. (Argonne National Lab., IL (USA) Chicago Univ., IL (USA). Dept. of Chemistry); Thurnauer, M.C. (Argonne National Lab., IL (USA))
1990-01-01
We have developed a general model for electron spin polarization which includes contributions from both CIDEP (chemically induced dynamic electron polarization) and CRP (correlated radical polarization). In this paper, we apply this model to sequential electron transfer in photosynthetic bacteria. Our model calculates the density matrix for the P{sup +}I{sup {minus}} radical pair and transfers the polarization as it develops to the P{sup +}Q{sup {minus}} radical pair. We illustrate several possible cases. One case is equivalent to CIDEP; no interactions are included on the secondary radical pair, P{sup +}Q{sup {minus}}. Another approximates CRPP by either increasing the transfer rate from P{sup +}I{sup {minus}} to P{sup +}Q{sup {minus}} or restricting interactions to the secondary radical pair, P{sup +}Q{sup {minus}}. Others allow interactions on both the primary and secondary radical pairs with various transfer rates. 15 refs., 4 figs.
Directory of Open Access Journals (Sweden)
Roman Cherniha
2016-06-01
Full Text Available The nonlinear mathematical model for solute and fluid transport induced by the osmotic pressure of glucose and albumin with the dependence of several parameters on the hydrostatic pressure is described. In particular, the fractional space available for macromolecules (albumin was used as a typical example and fractional fluid void volume were assumed to be different functions of hydrostatic pressure. In order to find non-uniform steady-state solutions analytically, some mathematical restrictions on the model parameters were applied. Exact formulae (involving hypergeometric functions for the density of fluid flux from blood to tissue and the fluid flux across tissues were constructed. In order to justify the applicability of the analytical results obtained, a wide range of numerical simulations were performed. It was found that the analytical formulae can describe with good approximation the fluid and solute transport (especially the rate of ultrafiltration for a wide range of values of the model parameters.
Podder, Jiban; Basu, Ritwik; Evitts, Richard William; Besant, Robert William
2015-11-01
In this paper, a study on the ternary NaCl-KCl-H2O system was carried out by an extractive metallurgy technique from mixed brine solutions of different compositions at room temperature (23°C). The surface morphology and microstructure were examined using a scanning electron microscope (SEM), electron backscattered diffraction (EBSD) and an energy dispersive X-ray (EDX) spectroscopy. The presence of Na{ }+ was found to reduce the stability of the solutions and increase the crystallization induction period, interfacial energy, energy of formation of the nucleus and greatly reduce the nucleation rate of KCl crystal. The surface morphology of KCl crystals is significantly changed due to presence of 5 to 10% (w/w) of NaCl as impurities in the binary solutions and shows the formation of co-crystals of different crystallographic orientation of NaCl on the KCl surface. In addition X-ray diffraction studies performed on KCl crystals grown in halite-sylvite binary solutions reveals that these crystals are cubic in nature and its lattice constant is 6.2952 Å when the NaCl concentration is small.
DEFF Research Database (Denmark)
Rong, Li; Elhadidi, B; Khalifa, H E
2011-01-01
In order to model and predict ammonia emissions from animal houses, it is important to determine the concentration on the emission surface correctly. In the current literature, Henry’s law is usually used to model the mass transfer through the gas–liquid surface (e.g. manure or aqueous solution......). The objective of this study is to investigate the accuracy of three models for Henry’s law constant (HLC) as well as functions derived from experimental vapor–liquid equilibrium (VLE) properties of ammonia water to determine the concentration on the liquid ammonia solutions surface in order to be used...
Model Checking Electronic Commerce Security Protocols Based on CTL
Institute of Scientific and Technical Information of China (English)
XIAO De-qin; ZHANG Huan-guo
2005-01-01
We present a model based on Computational Temporal Logic (CTL) methods for verifying security requirements of electronic commerce protocols. The model describes formally the authentication, confidentiality integrity,non-repudiation, denial of service and access control of the electronic commerce protocols. We illustrate as case study a variant of the Lu-Smolka protocol proposed by Lu-Smolka.Moreover, we have discovered two attacks that allow a dishonest user to purchase a good debiting the amount to another user. And also, we compared our work with relative research works and found that the formal way of this paper is more general to specify security protocols for E-Commerce.
Vortex Solutions in the Chern-Simons Stueckelberg Model
McKeon, D G C
1998-01-01
Vortex solutions to the classical field equations in a massive, renormalizable U(1) gauge model are considered in (2+1) dimensions. A vector field whose kinetic term consists of a Chern-Simons term plus a Stuekelberg mass term is coupled to a scalar field. If the classical scalar field is set equal to zero, then there are classical configurations of the vector field in which the magnetic flux is non-vanishing and finite. In contrast to the Nielsen-Olesen vortex, the magnetic field vanishes exponentially at large distances and diverges logarithmicly at short distances. This divergence, although not so severe as to cause the flux to diverge, results in the Hamiltonian becoming infinite. If the classical scalar field is no longer equal to zero, then the magnetic flux is not only finite, but quantized and the asymptotic behaviour of the field is altered so that the Hamiltonian no longer suffers from a divergence due to the field configuration at the origin. Furthermore, the asymptotic behaviour at infinity is dep...
Electron-scale reduced fluid models with gyroviscous effects
Passot, T.; Sulem, P. L.; Tassi, E.
2017-08-01
Reduced fluid models for collisionless plasmas including electron inertia and finite Larmor radius corrections are derived for scales ranging from the ion to the electron gyroradii. Based either on pressure balance or on the incompressibility of the electron fluid, they respectively capture kinetic Alfvén waves (KAWs) or whistler waves (WWs), and can provide suitable tools for reconnection and turbulence studies. Both isothermal regimes and Landau fluid closures permitting anisotropic pressure fluctuations are considered. For small values of the electron beta parameter e$ , a perturbative computation of the gyroviscous force valid at scales comparable to the electron inertial length is performed at order e)$ , which requires second-order contributions in a scale expansion. Comparisons with kinetic theory are performed in the linear regime. The spectrum of transverse magnetic fluctuations for strong and weak turbulence energy cascades is also phenomenologically predicted for both types of waves. In the case of moderate ion to electron temperature ratio, a new regime of KAW turbulence at scales smaller than the electron inertial length is obtained, where the magnetic energy spectrum decays like \\bot -13/3$ , thus faster than the \\bot -11/3$ spectrum of WW turbulence.
Eylenceoglu, Ender; Rafatov, Ismail; Kudryavtsev, Anatoly
2016-09-01
A modification of the conventional hybrid Monte Carlo - fluid model for glow discharge, which incorporates the electron energy equation, is considered. In the proposed model electrons are separated into two groups, namely, high energetic fast and low energetic slow (bulk) electrons. Density profiles of ions, slow electrons, and meta-stable particles are determined from the solution of corresponding continuity equations. Fast electrons, which are responsible for ionization and excitation events in the discharge, are simulated by the Monte-Carlo method. The temperature profile for slow electrons is obtained from the solution of the energy balance equation. The transport (mobility and diffusion) coefficients as well as the reaction rates for slow electrons are determined as functions of the electron temperature. Test calculations are carried out for the direct current glow discharge in argon within two-dimensional geometry. Comparison of the computed results with those obtained from the conventional fluid and hybrid models and the experimental data is done, the applicability and reliability of the proposed model is studied in details.
Neutrino-Electron Scattering and the Little Higgs Models
Institute of Scientific and Technical Information of China (English)
LI Na; YUE Chong-Xing; LI Xu-Xin
2011-01-01
The neutrino-electron scattering process is sensitive to the standard model (SM) and the new physics beyond the SM.We calculate the corrections of the littlest Higgs model and the SU(3) simple group model to the vee scattering cross section.Using the LSND experimental measured values,we obtain the bounds on the relevant free parameters,which might be compatible with those from the electroweak precision data.Neutrino-electron scattering is a simple and purely leptonic weak interaction process that can play an important role to perform precision tests of the standard model (SM) and probe various kinds of new physics models beyond the SM.[1-3] Thus,this process provides an ideal tool for electroweak studies.%The neutrino-electron scattering process is sensitive to the standard model (SM) and the new physics beyond the SM. We calculate the corrections of the littlest Higgs model and the SU(3) simple group model to the vee scattering cross section. Using the LSND experimental measured values, we obtain the bounds on the relevant free parameters, which might be compatible with those from the electroweak precision data.
A predictive standard model for heavy electron systems
Energy Technology Data Exchange (ETDEWEB)
Yang, Yifeng [Los Alamos National Laboratory; Curro, N J [UC DAVIS; Fisk, Z [UC DAVIS; Pines, D [UC DAVIS
2010-01-01
We propose a predictive standard model for heavy electron systems based on a detailed phenomenological two-fluid description of existing experimental data. It leads to a new phase diagram that replaces the Doniach picture, describes the emergent anomalous scaling behavior of the heavy electron (Kondo) liquid measured below the lattice coherence temperature, T*, seen by many different experimental probes, that marks the onset of collective hybridization, and enables one to obtain important information on quantum criticality and the superconducting/antiferromagnetic states at low temperatures. Because T* is {approx} J{sup 2} {rho}/2, the nearest neighbor RKKY interaction, a knowledge of the single-ion Kondo coupling, J, to the background conduction electron density of states, {rho}, makes it possible to predict Kondo liquid behavior, and to estimate its maximum superconducting transition temperature in both existing and newly discovered heavy electron families.
Two-Temperature Model of Nonequilibrium Electron Relaxation:. a Review
Singh, Navinder
The present paper is a review of the phenomena related to nonequilibrium electron relaxation in bulk and nano-scale metallic samples. The workable Two-Temperature Model (TTM) based on Boltzmann-Bloch-Peierls kinetic equation has been applied to study the ultra-fast (femto-second) electronic relaxation in various metallic systems. The advent of new ultra-fast (femto-second) laser technology and pump-probe spectroscopy has produced wealth of new results for micro- and nano-scale electronic technology. The aim of this paper is to clarify the TTM, conditions of its validity and nonvalidity, its modifications for nano-systems, to sum-up the progress, and to point out open problems in this field. We also give a phenomenological integro-differential equation for the kinetics of nondegenerate electrons that goes beyond the TTM.
Calcite growth kinetics: Modeling the effect of solution stoichiometry
Wolthers, M.; Nehrke, G.; Gustafsson, J.P.; Van Cappellen, P.
2012-01-01
Until recently the influence of solution stoichiometry on calcite crystal growth kinetics has attracted little attention, despite the fact that in most aqueous environments calcite precipitates from non-stoichiometric solution. In order to account for the dependence of the calcite crystal growth rat
Murata, Aki; Kattubadi, Sailaja
2012-01-01
In considering mathematics problem solving as a model-eliciting activity (Lesh & Doerr, 2003; Lesh & Harel, 2003; Lesh & Zawojewski, 2008), it is important to know "what" students are modeling for the problems: situations or solutions. This study investigated Grade 3 students' mathematization process by examining how they modeled different…
Kinetic modelling of runaway electrons in dynamic scenarios
Stahl, A.; Embréus, O.; Papp, G.; Landreman, M.; Fülöp, T.
2016-11-01
Improved understanding of runaway-electron formation and decay processes are of prime interest for the safe operation of large tokamaks, and the dynamics of the runaway electrons during dynamical scenarios such as disruptions are of particular concern. In this paper, we present kinetic modelling of scenarios with time-dependent plasma parameters; in particular, we investigate hot-tail runaway generation during a rapid drop in plasma temperature. With the goal of studying runaway-electron generation with a self-consistent electric-field evolution, we also discuss the implementation of a collision operator that conserves momentum and energy and demonstrate its properties. An operator for avalanche runaway-electron generation, which takes the energy dependence of the scattering cross section and the runaway distribution into account, is investigated. We show that the simplified avalanche model of Rosenbluth and Putvinskii (1997 Nucl. Fusion 37 1355) can give inaccurate results for the avalanche growth rate (either lower or higher) for many parameters, especially when the average runaway energy is modest, such as during the initial phase of the avalanche multiplication. The developments presented pave the way for improved modelling of runaway-electron dynamics during disruptions or other dynamic events.
Fu, Boyi
2015-04-01
The electron deficiency and trans planar conformation of bithiazole is potentially beneficial for the electron transport performance of organic semiconductors. However, the incorporation of bithiazole into polymers through a facile synthetic strategy remains a challenge. Herein, 2,2’-bithiazole was synthesized in one step and copolymerized with dithienyldiketopyrrolopyrrole to afford poly(dithienyldiketopyrrolopyrrole-bithiazole), PDBTz. PDBTz exhibited electron mobility reaching 0.3 cm2V-1s-1 in organic field-effect transistor (OFET) configuration; this contrasts with a recently discussed isoelectronic conjugated polymer comprising an electron rich bithiophene and dithienyldiketopyrrolopyrrole, which displays merely hole transport characteristics. This inversion of charge carrier transport characteristics confirms the significant potential for bithiazole in the development of electron transport semiconducting materials. Branched 5-decylheptacyl side chains were incorporated into PDBTz to enhance polymer solubility, particularly in non-halogenated, more environmentally compatible solvents. PDBTz cast from a range of non-halogenated solvents exhibited film morphologies and field-effect electron mobility similar to those cast from halogenated solvents.
Structural model of the 50S subunit of E.Coli ribosomes from solution scattering
Energy Technology Data Exchange (ETDEWEB)
Svergun, D.I.; Koch, M.H.J. [Hamburg Outstation (Germany); Pedersen, J.S. [Riso National Laboratory, Roskilde (Denmark); Serdyuk, I.N. [Inst. of Protein Research, Moscow (Russian Federation)
1994-12-31
The application of new methods of small-angle scattering data interpretation to a contrast variation study of the 50S ribosomal subunit of Escherichia coli in solution is described. The X-ray data from contrast variation with sucrose are analyzed in terms of the basic scattering curves from the volume inaccessible to sucrose and from the regions inside this volume occupied mainly by RNA and by proteins. From these curves models of the shape of the 50S and its RNA-rich core are evaluated and positioned so that their difference produces a scattering curve which is in good agreement with the scattering from the protein moiety. Basing on this preliminary model, the X-ray and neutron contrast variation data of the 50S subunit in aqueous solutions are interpreted in the frame of the advanced two-phase model described by the shapes of the 50S subunit and its RNA-rich core taking into account density fluctuations inside the RNA and the protein moiety. The shape of the envelope of the 50S subunit and of the RNA-rich core are evaluated with a resolution of about 40A. The shape of the envelope is in good agreement with the models of the 50S subunit obtained from electron microscopy on isolated particles. The shape of the RNA-rich core correlates well with the model of the entire particle determined by the image reconstruction from ordered sheets indicating that the latter model which is based on the subjective contouring of density maps is heavily biased towards the RNA.
Electron-gas clusters: the ultimate jellium model
Koskinen, M.; Lipas, P. O.; Manninen, M.
1995-12-01
The local spin-density approximation is used to calculate ground- and isomeric-state geometries of jellium clusters with 2 to 22 electrons. The positive background charge of the model is completely deformable, both in shape and in density. The model has no input parameters. The resulting shapes of the clusters exhibit breaking of axial and inversion symmetries; in general the shapes are far from ellipsoidal. Those clusters which lack inversion symmetry are extremely soft against odd-multipole deformations. Some clusters can be interpreted as molecules built from magic clusters. The deformation produces a gap at the Fermi level. This results in a regular odd-even staggering of the total energy per electron and of the HOMO level. The strongly deformed 14-electron cluster is semimagic. Stable isomers are predicted. The splitting of the plasmon resonance due to deformation is estimated on a classical argument.
Electronic market models for decision support systems on the Web
Institute of Scientific and Technical Information of China (English)
谢勇; 王红卫; 费奇
2004-01-01
With the prevalence of the Web, most decision-makers are likely to use the Web to support their decision-making. Web-based technologies are leading a major stream of researching decision support systems (DSS). We propose a formal definition and a conceptual framework for Web-based open DSS (WODSS). The formal definition gives an overall view of WODSS, and the conceptual framework based on browser/broker/server computing mode employs the electronic market to mediate decision-makers and providers, and facilitate sharing and reusing of decision resources. We also develop an admitting model, a trading model and a competing model of electronic market in WODSS based on market theory in economics. These models reveal the key mechanisms that drive WODSS operate efficiently.
Fuse Modeling for Reliability Study of Power Electronics Circuits
DEFF Research Database (Denmark)
Bahman, Amir Sajjad; Iannuzzo, Francesco; Blaabjerg, Frede
2017-01-01
This paper describes a comprehensive modeling approach on reliability of fuses used in power electronic circuits. When fuses are subjected to current pulses, cyclic temperature stress is introduced to the fuse element and will wear out the component. Furthermore, the fuse may be used in a large...
An Emerging Model for Student Feedback: Electronic Distributed Evaluation
Brunk-Chavez, Beth; Arrigucci, Annette
2012-01-01
In this article we address several issues and challenges that the evaluation of writing presents individual instructors and composition programs as a whole. We present electronic distributed evaluation, or EDE, as an emerging model for feedback on student writing and describe how it was integrated into our program's course redesign. Because the…
Toward a generic model of trust for electronic commerce
Tan, YH; Thoen, W
2000-01-01
The authors present a generic model of trust for electronic commerce consisting of two basic components, party trust and control trust, based on the concept that trust in a transaction with another party combines trust in the other parry and trust in the control mechanisms that ensure the successful
Fuse Modeling for Reliability Study of Power Electronics Circuits
DEFF Research Database (Denmark)
Bahman, Amir Sajjad; Iannuzzo, Francesco; Blaabjerg, Frede
2017-01-01
This paper describes a comprehensive modeling approach on reliability of fuses used in power electronic circuits. When fuses are subjected to current pulses, cyclic temperature stress is introduced to the fuse element and will wear out the component. Furthermore, the fuse may be used in a large...
High power electronics package: from modeling to implementation
Yuan, C.A.; Kregting, R.; Ye, H.; Driel, W. van; Gielen, A.W.J.; Zhang, G.Q.
2011-01-01
Power electronics, such as high power RF components and high power LEDs, requires the combination of robust and reliable package structures, materials, and processes to guarantee their functional performance and lifetime. We started with the thermal and thermal-mechanical modeling of such component
Dimers of Azurin as model systems for electron transfer
Jongh, Thyra Estrid de
2006-01-01
This thesis describes the investigation of crosslinked complexes of the blue copper protein azurin by means of spectroscopic techniques such as Uv-Vis and NMR as well as by X-ray crystallography. These non-physiological dimers serve as model systems for interprotein electron transfer (ET) and allow
Toward a generic model of trust for electronic commerce
Tan, YH; Thoen, W
2000-01-01
The authors present a generic model of trust for electronic commerce consisting of two basic components, party trust and control trust, based on the concept that trust in a transaction with another party combines trust in the other parry and trust in the control mechanisms that ensure the successful
Technical Communicator: A New Model for the Electronic Resources Librarian?
Hulseberg, Anna
2016-01-01
This article explores whether technical communicator is a useful model for electronic resources (ER) librarians. The fields of ER librarianship and technical communication (TC) originated and continue to develop in relation to evolving technologies. A review of the literature reveals four common themes for ER librarianship and TC. While the…
Kurahashi, Naoya; Karashima, Shutaro; Tang, Ying; Horio, Takuya; Abulimiti, Bumaliya; Suzuki, Yoshi-Ichi; Ogi, Yoshihiro; Oura, Masaki; Suzuki, Toshinori
2014-05-07
The streaming potentials of liquid beams of aqueous NaCl, NaBr, and NaI solutions are measured using soft X-ray, He(I), and laser multiphoton ionization photoelectron spectroscopy. Gaseous molecules are ionized in the vicinity of liquid beams and the photoelectron energy shifts are measured as a function of the distance between the ionization point and the liquid beam. The streaming potentials change their polarity with concentration of electrolytes, from which the singular points of concentration eliminating the streaming potentials are determined. The streaming currents measured in air also vanish at these concentrations. The electron binding energies of liquid water and I(-), Br(-), and Cl(-) anions are revisited and determined more accurately than in previous studies.
Functional models of power electronic components for system studies
Tam, Kwa-Sur; Yang, Lifeng; Dravid, Narayan
1991-01-01
A novel approach to model power electronic circuits has been developed to facilitate simulation studies of system-level issues. The underlying concept for this approach is to develop an equivalent circuit, the functional model, that performs the same functions as the actual circuit but whose operation can be simulated by using larger time step size and the reduction in model complexity, the computation time required by a functional model is significantly shorter than that required by alternative approaches. The authors present this novel modeling approach and discuss the functional models of two major power electronic components, the DC/DC converter unit and the load converter, that are being considered by NASA for use in the Space Station Freedom electric power system. The validity of these models is established by comparing the simulation results with available experimental data and other simulation results obtained by using a more established modeling approach. The usefulness of this approach is demonstrated by incorporating these models into a power system model and simulating the system responses and interactions between components under various conditions.
Optimization Model for Environmental Stress Screening of Electronic Components
Institute of Scientific and Technical Information of China (English)
无
2001-01-01
Environmental stress screening (ESS) is a technological process to reduce the costly early field failure ofelectronic components. This paper builds an optimization model for ESS of electronic components to obtain the optimalESS duration. The failure phenomena of ESS are modeled by mix ed distribution, and optimal ESS duration is definedby maximizing life-cycle cost savings under the condition of meeting reliability requirement.
MULER: Building an Electronic Resource Management (ERM Solution at York University
Directory of Open Access Journals (Sweden)
Aaron August Lupton
2012-01-01
Full Text Available Many university libraries now utilize an Electronic Resource Management (ERM system to assist with operations related to electronic resources. An ERM is a relational database containing information such as suppliers, costs, holdings, and renewal dates for electronic resources, both at the database and title levels. While commercial ERM products are widely available, some institutions are custom building their own ERM in- house. This article describes how York University in Toronto, Canada, did just that by building a system called Managing University Library Electronic Resources (MULER. The article details the background and history of how electronic resources were managed pre-MULER; why a new ERM was needed; the planning process; the current and innovative functions of MULER, including integration of MULER data into York University Libraries search and discovery layer, Vufind; subject tagging in MULER; new functions to be added; and lessons learned from the project. Positive and negative implications of choosing an in-house project over paying for a commercial product are also discussed.
A new parametrizable model of molecular electronic structure
Laikov, Dimitri N
2011-01-01
A new electronic structure model is developed in which the ground state energy of a molecular system is given by a Hartree-Fock-like expression with parametrized one- and two-electron integrals over an extended (minimal + polarization) set of orthogonalized atom-centered basis functions, the variational equations being solved formally within the minimal basis but the effect of polarization functions being included in the spirit of second-order perturbation theory. It is designed to yield good dipole polarizabilities and improved intermolecular potentials with dispersion terms. The molecular integrals include up to three-center one-electron and two-center two-electron terms, all in simple analytical forms. A method to extract the effective one-electron Hamiltonian of nonlocal-exchange Kohn-Sham theory from the coupled-cluster one-electron density matrix is designed and used to get its matrix representation in a molecule-intrinsic minimal basis as an input to the paramtrization procedure -- making a direct link...
Modeling of Dilute Polymer Solutions in Confined Space
DEFF Research Database (Denmark)
Wang, Yanwei
2009-01-01
by simple mathematical analyses. When the CABS method is applied to compute the equilibrium distribution (the equilibrium partition coefficient, Ko) of polymers between a dilute macroscopic solution phase and a solution confined by inert impenetrable boundaries, a sphere-like universal partitioning feature...... of polymers in SEC, one may reach a conclusion that SEC fractionates polymers based on the steric exclusion radius, Rs . The CABS method is further applied to determine the depletion profiles of dilute polymer solutions confined to a slit or near an inert wall. We show that the entire spatial density...... that (i) the depletion layer thickness, 6, is the same no matter which reference point is used to describe the depletion profile, and (ii) the value of 6 equals the steric exclusion radius, Rs , of the macromolecule in free solution. Both results hold not only for ideal polymers as has been noticed before...
Jani, Margi; Raval, Dhyey; Pati, Ranjan; Mukhopadhyay, Indrajit; Ray, Abhijit
2017-06-01
Structure, optical and electronic properties of solid solution thin films of Zn(O,S) developed by spray pyrolysis are investigated, and the effect of annealing is investigated for a possible improvement in its electrical properties. A variation in the initial sulphur (S) precursor concentration with fixed Zn-precursor concentration during the spray deposition produces a solid solution of ZnO and ZnS. Both the lower (80%) concentrations of the S-precursor cause isovalent substitution in the system, retaining hexagonal ZnO and cubic ZnS structures, respectively, whereas other concentrations lead to the formation of films in a phase-separated solid solution of ZnO and ZnS. A strain-induced shift in optical band gap in the range of 3.3-3.6 eV is unique in the system with a strong bowing effect. A post-annealing at 370 °C in air is found to improve electron mobility in the film, whereas the annealing in argon ambient improves its electrical conductivity.
Fraccaro, Paolo; Dentone, Chiara; Fenoglio, Daniela; Giacomini, Mauro
2013-12-01
Clinical Trials (CTs) are indispensable instruments for evidence-based medicine and frequently necessitate the management, sharing and analysis of large amounts of data amongst partners in different locations. To effectively satisfy these requirements, the proposed solution combines a web platform and a Clinical Data Management System (CDMS) to exploit the strengths of Electronic Health Records (EHR) and Electronic Data Capture (EDC) systems. The core of the proposal is a relational database which has high data structuring characteristics and utilises biomedical controlled vocabularies (e.g. LOINC and ICD). In addition, units and normality ranges were collected for data comparison through the application of the Z-score transformation. The obtained CDMS preserves the EDC's flexibility and user autonomy and permits the creation of patient cohorts, as in the EHR. Accordingly, clinical information, after the initial recording, is available for different simultaneous multicentre CTs. Furthermore, interface runtime controls guarantee high data quality during data entering processes. Currently, the proposed system has been developed in the HIV and eye diseases fields in Italy. The proposed solution is flexible and suitable to perform multicentre research within a varying range of medical domains. In the future, the automatic importation of information from hospitals has been planned through an HL7 standard interface which would improve both data quantity and quality.
Exact solutions to a nonlinear dispersive model with variable coefficients
Energy Technology Data Exchange (ETDEWEB)
Yin Jun [Department of Applied Mathematics, Southwestern University of Finance and Economics, Chengdu 610074 (China); Lai Shaoyong [Department of Applied Mathematics, Southwestern University of Finance and Economics, Chengdu 610074 (China)], E-mail: laishaoy@swufe.edu.cn; Qing Yin [Department of Applied Mathematics, Southwestern University of Finance and Economics, Chengdu 610074 (China)
2009-05-15
A mathematical technique based on an auxiliary differential equation and the symbolic computation system Maple is employed to investigate a prototypical and nonlinear K(n, n) equation with variable coefficients. The exact solutions to the equation are constructed analytically under various circumstances. It is shown that the variable coefficients and the exponent appearing in the equation determine the quantitative change in the physical structures of the solutions.
Local Martingale and Pathwise Solutions for an Abstract Fluids Model
Debussche, Arnaud; Glatt-Holtz, Nathan; Temam, Roger
2010-01-01
We establish the existence and uniqueness of both local martingale and local pathwise solutions of an abstract nonlinear stochastic evolution system. The primary application of this abstract framework is to infer the local existence of strong, pathwise solutions to the 3D primitive equations of the oceans and atmosphere forced by a nonlinear multiplicative white noise. Instead of developing our results specifically for the 3D primitive equations we choose to develop them in a slightly abstrac...
Choi, Hyeju; Ko, Haye Min; Cho, Nara; Song, Kihyung; Lee, Jae Kwan; Ko, Jaejung
2012-10-01
New electron-rich anthracene derivatives containing triarylamine hole stabilizers, 2,6-bis[5,5'-bis(N,N'-diphenylaniline)-2,2'-bithiophen-5-yl]-9,10-bis-[(triisopropylsilyl)ethynyl]anthracene (TIPSAntBT-TPA) and 2,6-bis(5,5'-bis{4-[bis(9,9-dimethyl-9H-fluoren-2-yl)amino]phenyl}-2,2'-bithiophen-5-yl)-9,10-bis-[(triisopropylsilyl)ethynyl]anthracene (TIPSAntBT-bisDMFA), linked with π-conjugated bithiophene bridges, were synthesized and their photovoltaic characteristics were investigated in solution-processed small-molecule organic solar cells (SMOSCs). These new materials exhibited superior intramolecular charge transfer from triarylamine to anthracene, leading to a more electron-rich anthracene core that facilitated electron transfer into phenyl-C(61)-butyric acid methyl ester. Compared with TIPSAntBT and triarylamine, these materials show a threefold improvement in hole-transporting properties and better photovoltaic performance in solution-processed SMOSCs, with the best power conversion efficiency being 2.96 % at a high open-circuit voltage of 0.85 V.
Caricato, Marco
2013-07-28
The calculation of vertical electronic transition energies of molecular systems in solution with accurate quantum mechanical methods requires the use of approximate and yet reliable models to describe the effect of the solvent on the electronic structure of the solute. The polarizable continuum model (PCM) of solvation represents a computationally efficient way to describe this effect, especially when combined with coupled cluster (CC) methods. Two formalisms are available to compute transition energies within the PCM framework: State-Specific (SS) and Linear-Response (LR). The former provides a more complete account of the solute-solvent polarization in the excited states, while the latter is computationally very efficient (i.e., comparable to gas phase) and transition properties are well defined. In this work, I review the theory for the two formalisms within CC theory with a focus on their computational requirements, and present the first implementation of the LR-PCM formalism with the coupled cluster singles and doubles method (CCSD). Transition energies computed with LR- and SS-CCSD-PCM are presented, as well as a comparison between solvation models in the LR approach. The numerical results show that the two formalisms provide different absolute values of transition energy, but similar relative solvatochromic shifts (from nonpolar to polar solvents). The LR formalism may then be used to explore the solvent effect on multiple states and evaluate transition probabilities, while the SS formalism may be used to refine the description of specific states and for the exploration of excited state potential energy surfaces of solvated systems.
Directory of Open Access Journals (Sweden)
O.Ya.Farenyuk
2006-01-01
Full Text Available The pseudospin-electron model with tunneling splitting of levels is considered. Generalization of dynamic mean-field method for systems with correlated hopping was applied to the investigation of the model. Electron spectra, electron concentrations, average values of pseudospins and grand canonical potential were calculated within the alloy-analogy approximation. Electron spectrum and dependencies of the electron concentrations on chemical potential were obtained. It was shown that in the alloy-analogy approximation, the model possesses the first order phase transition to ferromagnetic state with the change of chemical potential and the second order phase transition with the change of temperature.
Serdenko, T. V.; Barabash, Y. M.; Knox, P. P.; Seifullina, N. Kh.
2016-06-01
The present work is related to the investigation of slow kinetics of electron transport in the reaction centers (RCs) of Rhodobacter sphaeroides. Experimental data on the absorption kinetics of aqueous solutions of reaction centers at different modes of photoexcitation are given. It is shown that the kinetics of oxidation and reduction of RCs are well described by the sum of three exponential functions. This allows to suggest a two-level kinetic model for electron transport in the RC as a system of four electron-conformational states which correspond to three balance differential equations combined with state equation. The solution of inverse problem made it possible to obtain the rate constant values in kinetic equations for different times and intensities of exciting light. Analysis of rate constant values in different modes of RC excitation allowed to suggest that two mechanisms of structural changes are involved in RC photo-oxidation. One mechanism leads to the increment of the rate of electron return, another one—to its drop. Structural changes were found out to occur in the RCs under incident light. After light was turned off, the reduction of RCs was determined by the second mechanism.
Transformer Model in Wide Frequency Bandwidth for Power Electronics Systems
Directory of Open Access Journals (Sweden)
Carlos Gonzalez-Garcia
2013-01-01
Full Text Available The development of the smart grids leads to new challenges on the power electronics equipment and power transformers. The use of power electronic transformer presents several advantages, but new problems related with the application of high frequency voltage and current components come across. Thus, an accurate knowledge of the transformer behavior in a wide frequency range is mandatory. A novel modeling procedure to relate the transformer physical behavior and its frequency response by means of electrical parameters is presented. Its usability is demonstrated by an example where a power transformer is used as filter and voltage reducer in an AC-DC-AC converter.
Hopping electron model with geometrical frustration: kinetic Monte Carlo simulations
Terao, Takamichi
2016-09-01
The hopping electron model on the Kagome lattice was investigated by kinetic Monte Carlo simulations, and the non-equilibrium nature of the system was studied. We have numerically confirmed that aging phenomena are present in the autocorrelation function C ({t,tW )} of the electron system on the Kagome lattice, which is a geometrically frustrated lattice without any disorder. The waiting-time distributions p(τ ) of hopping electrons of the system on Kagome lattice has been also studied. It is confirmed that the profile of p (τ ) obtained at lower temperatures obeys the power-law behavior, which is a characteristic feature of continuous time random walk of electrons. These features were also compared with the characteristics of the Coulomb glass model, used as a model of disordered thin films and doped semiconductors. This work represents an advance in the understanding of the dynamics of geometrically frustrated systems and will serve as a basis for further studies of these physical systems.
Stability of the Bifurcation Solutions for a Predator-Prey Model
Institute of Scientific and Technical Information of China (English)
孟义杰; 王一夫
2003-01-01
The bifurcation solution of the nonnegative steady-state of a reaction-diffusion system was investigated. The combination of the sturm-type eigenvalue and the theorem of bifurcation was used to study the local coexistence solutions, and obtain the stability of bifurcation solutions. The system model describes predator-prey interaction in an unstirred chemostat.
Institute of Scientific and Technical Information of China (English)
DONG BoQing; JIANG Wei
2008-01-01
This article concerns large time behavior of Ladyzhenskaya model for incompressible viscous flows in R3. Based on linear Lp-Lq estimates, the auxiliary decay properties of the solutions and generalized Gronwall type arguments, some optimal upper and lower bounds for the decay of higher order derivatives of solutions are derived without assuming any decay properties of solutions and using Fourier splitting technology.
General classical solutions in the noncommutative CP^(N-1) model
Foda, O E; Jones, D R T
2002-01-01
We give an explicit construction of general classical solutions for the noncommutative CP^(N-1) model in two dimensions, showing that they correspond to integer values for the action and topological charge. We also give explicit solutions for the Dirac equation in the background of these general solutions and show that the index theorem is satisfied.
General classical solutions in the noncommutative CP{sup N-1} model
Energy Technology Data Exchange (ETDEWEB)
Foda, O.; Jack, I.; Jones, D.R.T
2002-10-31
We give an explicit construction of general classical solutions for the noncommutative CP{sup N-1} model in two dimensions, showing that they correspond to integer values for the action and topological charge. We also give explicit solutions for the Dirac equation in the background of these general solutions and show that the index theorem is satisfied.
Institute of Scientific and Technical Information of China (English)
无
2002-01-01
As indicated by kinetic ESR measurements, the key factor to affect electron recombination in the process of PET between C60 and amines is the space between donor and C60. To increase solubility of C60 in water, it was incorporated into micelle of surfactants.
Peroxyl Radical Reactions in Water Solution: A Gym for Proton-Coupled Electron-Transfer Theories.
Amorati, Riccardo; Baschieri, Andrea; Morroni, Gloria; Gambino, Rossana; Valgimigli, Luca
2016-06-01
The reactions of alkylperoxyl radicals with phenols have remained difficult to investigate in water. We describe herein a simple and reliable method based on the inhibited autoxidation of water/THF mixtures, which we calibrated against pulse radiolysis. With this method we measured the rate constants kinh for the reactions of 2-tetrahydrofuranylperoxyl radicals with reference compounds: urate, ascorbate, ferrocenes, 2,2,5,7,8-pentamethyl-6-chromanol, Trolox, 6-hydroxy-2,5,7,8-tetramethylchroman-2-acetic acid, 2,6-di-tert-butyl-4-methoxyphenol, 4-methoxyphenol, catechol and 3,5-di-tert-butylcatechol. The role of pH was investigated: the value of kinh for Trolox and 4-methoxyphenol increased 11- and 50-fold from pH 2.1 to 12, respectively, which indicate the occurrence of a SPLET-like mechanism. H(D) kinetic isotope effects combined with pH and solvent effects suggest that different types of proton-coupled electron transfer (PCET) mechanisms are involved in water: less electron-rich phenols react at low pH by concerted electron-proton transfer (EPT) to the peroxyl radical, whereas more electron-rich phenols and phenoxide anions react by multi-site EPT in which water acts as proton relay.
Pliotas, Christos; Ward, Richard; Branigan, Emma; Rasmussen, Akiko; Hagelueken, Gregor; Huang, Hexian; Black, Susan S; Booth, Ian R; Schiemann, Olav; Naismith, James H
2012-10-02
The heptameric mechanosensitive channel of small conductance (MscS) provides a critical function in Escherichia coli where it opens in response to increased bilayer tension. Three approaches have defined different closed and open structures of the channel, resulting in mutually incompatible models of gating. We have attached spin labels to cysteine mutants on key secondary structural elements specifically chosen to discriminate between the competing models. The resulting pulsed electron-electron double resonance (PELDOR) spectra matched predicted distance distributions for the open crystal structure of MscS. The fit for the predictions by structural models of MscS derived by other techniques was not convincing. The assignment of MscS as open in detergent by PELDOR was unexpected but is supported by two crystal structures of spin-labeled MscS. PELDOR is therefore shown to be a powerful experimental tool to interrogate the conformation of transmembrane regions of integral membrane proteins.
Analog electronic model of the lobster pyloric central pattern generator
Energy Technology Data Exchange (ETDEWEB)
Volkovskii, A [Institute for Nonlinear Science, University of California San Diego, CA (United States); Brugioni, S [Institute for Nonlinear Science, University of California San Diego, CA (United States); Istituto Nazionale di Ottica Applicata Largo E. Fermi 6 50125 Florence (Italy); Levi, R [Institute for Nonlinear Science, University of California San Diego, CA (United States); Rabinovich, M [Institute for Nonlinear Science, University of California San Diego, CA (United States); Selverston, A [Institute for Nonlinear Science, University of California San Diego, CA (United States); Abarbane, H D I [Institute for Nonlinear Science, University of California San Diego, CA (United States)
2005-01-01
An electronic circuit intended to simulate the nonlinear dynamics of a simplified 3-cell model of the pyloric central pattern generator in California spiny lobster stomato gastric ganglion is presented. The model employs the synaptic phase locked loop (SPLL) concept where the frequency of oscillations of a postsynaptic cell is mainly controlled by the synaptic current which depends on the phase shift between the oscillations. The theoretical study showed that the system has a stable steady state with correct phase shifts between the oscillations and that this regime is stable when the frequency of the pacemaker cell is varied over a wide range. The main bifurcations in the system were studied analytically, in computer simulations, and in experiments with the electronic circuit. The experimental measurements are in good agreement with the expectations of the theoretical model.
The Development Model Electronic Commerce of Regional Agriculture
Kang, Jun; Cai, Lecai; Li, Hongchan
With the developing of the agricultural information, it is inevitable trend of the development of agricultural electronic commercial affairs. On the basis of existing study on the development application model of e-commerce, combined with the character of the agricultural information, compared with the developing model from the theory and reality, a new development model electronic commerce of regional agriculture base on the government is put up, and such key issues as problems of the security applications, payment mode, sharing mechanisms, and legal protection are analyzed, etc. The among coordination mechanism of the region is discussed on, it is significance for regulating the development of agricultural e-commerce and promoting the regional economical development.
Time domain simulation and modeling of power electronic circuits. Development of a simulation tool
Energy Technology Data Exchange (ETDEWEB)
Mo, O.
1993-08-01
This thesis presents the results of a study on the topic: Time domain modeling and simulation of power electronic circuits. The objectives of the presented work have been to improve and expand the simulation program KREAN. This also included search for, development and implementation of models suited for analysis of power electronic circuits. The main contribution of the work is the improved KREAN program itself and the models created for the program. Further, the work has led to this thesis which is a documentation of the applied methods. The thesis shows how to create a power electronic simulation tool and how to meet the special problems encountered in power electronic circuits. Among the major improvements of KREAN are: Better methods for solution of nonlinear algebraic equations. Major modifications have been implemented in the modified Newton iteration method. The old method suffered from insufficient control of the iteration error. Improved efficiency, accuracy and robustness of the breakpoint detection methods (breakpoints are time instants of discontinuous behavior in models). A new linear circuit now replaces the nonlinear modules at each stage in the iteration. The old one could give serious errors in the results and was not applicable after introduction of voltage response terminals. Several new models have been implemented as KREAN modules. Together with the old basic ones, they form a powerful set for simulation of power electronics. The thesis describes the applied methods, the implemented models and also presents results from study of the accuracy and efficiency of the program. The applied methods in the program are stated to be good enough for most simulation purposes. 100 refs., 93 figs., 14 tabs.
Modeling precipitation from concentrated solutions with the EQ3/6 chemical speciation codes
Energy Technology Data Exchange (ETDEWEB)
Brown, L.F.; Ebinger, M.H.
1995-01-13
One of the more important uncertainties of using chemical speciation codes to study dissolution and precipitation of compounds is the results of modeling which depends on the particular thermodynamic database being used. The authors goal is to investigate the effects of different thermodynamic databases on modeling precipitation from concentrated solutions. They used the EQ3/6 codes and the supplied databases to model precipitation in this paper. One aspect of this goal is to compare predictions of precipitation from ideal solutions to similar predictions from nonideal solutions. The largest thermodynamic databases available for use by EQ3/6 assume that solutions behave ideally. However, two databases exist that allow modeling nonideal solutions. The two databases are much less extensive than the ideal solution data, and they investigated the comparability of modeling ideal solutions and nonideal solutions. They defined four fundamental problems to test the EQ3/6 codes in concentrated solutions. Two problems precipitate Ca(OH){sub 2} from solutions concentrated in Ca{sup ++}. One problem tests the precipitation of Ca(OH){sub 2} from high ionic strength (high concentration) solutions that are low in the concentrations of precipitating species (Ca{sup ++} in this case). The fourth problem evaporates the supernatant of the problem with low concentrations of precipitating species. The specific problems are discussed.
Creamer, Neil J; Baxter-Plant, Victoria S; Henderson, John; Potter, M; Macaskie, Lynne E
2006-09-01
Biomass of Desulfovibrio desulfuricans was used to recover Au(III) as Au(0) from test solutions and from waste electronic scrap leachate. Au(0) was precipitated extracellularly by a different mechanism from the biodeposition of Pd(0). The presence of Cu(2+) ( approximately 2000 mg/l) in the leachate inhibited the hydrogenase-mediated removal of Pd(II) but pre-palladisation of the cells in the absence of added Cu(2+) facilitated removal of Pd(II) from the leachate and more than 95% of the Pd(II) was removed autocatalytically from a test solution supplemented with Cu(II) and Pd(II). Metal recovery was demonstrated in a gas-lift electrobioreactor with electrochemically generated hydrogen, followed by precipitation of recovered metal under gravity. A 3-stage bioseparation process for the recovery of Au(III), Pd(II) and Cu(II) is proposed.
Energy Technology Data Exchange (ETDEWEB)
Marconnet, C. [Laboratoire de Genie des Procedes et des Materiaux, Ecole Centrale Paris, Grande Voie des Vignes, 92290 CHATENAY-MALABRY (France)], E-mail: cyril.marconnet@yahoo.fr; Wouters, Y. [Science et Ingenierie des Materiaux et Procedes, Institut National Polytechnique de Grenoble, F-38402 Saint-Martin d' Heres Cedex (France); Miserque, F. [Laboratoire de Reactivite des Surfaces et des Interfaces, CEA Saclay, Bat. 391, 91191 GIF-SUR-YVETTE (France); Dagbert, C. [Laboratoire de Genie des Procedes et des Materiaux, Ecole Centrale Paris, Grande Voie des Vignes, 92290 CHATENAY-MALABRY (France)], E-mail: catherine.dagbert@ecp.fr; Petit, J.-P. [Laboratoire d' Electrochimie et de Physico-chimie des Materiaux et des Interfaces, INPG, F-38402 Saint-Martin d' Heres Cedex (France); Galerie, A. [Science et Ingenierie des Materiaux et Procedes, Institut National Polytechnique de Grenoble, F-38402 Saint-Martin d' Heres Cedex (France); Feron, D. [Service de Corrosion et du Comportement des Materiaux dans leur Environnement, CEA Saclay, Bat. 458, 91191 GIF-SUR-YVETTE (France)
2008-12-01
This article deals with the interaction between the passive layer formed on UNS S30403 and S31254 stainless steels and an enzymatic solution containing glucose oxidase (GOx) and its substrate D-glucose. This enzymatic solution is often used to reproduce in laboratory the ennoblement occuring in non-sterile aerated aqueous environments because of the biofilm settlement on the surface of the metallic material. GOx catalyses the oxidation of D-glucose to gluconic acid by reducing oxygen to hydrogen peroxide and produces an organic acid. Thanks to photocurrent measurements, XPS analysis and Mott-Schottky diagrams, it is here shown that such an environment generates modifications in the chemical composition and electronic structure of the passive layer: it induces a relative enrichment of the n-type semi-conducting phase containing chromium (chromine Cr{sub 2}O{sub 3}) and an increase of the donors density in the space charge region.
Electronic structure of PrBa2Cu3O7 within LSDA+U: Different self-consistent solutions
Directory of Open Access Journals (Sweden)
M R Mohammadizadeh
2009-08-01
Full Text Available Based on the density functional theory and using the full-potential linearized augmented-plane-waves method the electronic structure of PrBa2Cu3O7 (Pr123 system was calculated. The rotationally invariant local spin density approximation plus Hubbard parameter U was employed for Pr(4f orbitals. One self-consistent solution more stable than the previous solution, which has been proposed by Liechtenstein and Mazin (LM, was found. In contrast to the LM solution, it can explain the results of the 17O NMR spectroscopy study of nonsuperconducting Pr123 samples. This new solution favors the suggestion that the pure Pr123 samples should be intrinsically superconductor and metal similar to the other RBa2Cu3O7 (R=Y or a rare earth element samples. The imperfections cause the superconducting holes are transferred to the nonsuperconducting hole states around the high-symmetry (π/a, π/b, kz line in the Brillouin zone and so, superconductivity is suppressed in the conventional samples. It predicts that the superconducting 2pσ holes in the O2 sites of nonsuperconducting Pr123 samples should be depleted and the ones in the O3 sites should be almost unchanged .
Han, Seungsuk; Yarkony, David R
2011-05-07
A method for obtaining partial differential cross sections for low energy electron photodetachment in which the electronic states of the residual molecule are strongly coupled by conical intersections is reported. The method is based on the iterative solution to a Lippmann-Schwinger equation, using a zeroth order Hamiltonian consisting of the bound nonadiabatically coupled residual molecule and a free electron. The solution to the Lippmann-Schwinger equation involves only standard electronic structure techniques and a standard three-dimensional free particle Green's function quadrature for which fast techniques exist. The transition dipole moment for electron photodetachment, is a sum of matrix elements each involving one nonorthogonal orbital obtained from the solution to the Lippmann-Schwinger equation. An expression for the electron photodetachment transition dipole matrix element in terms of Dyson orbitals, which does not make the usual orthogonality assumptions, is derived.
Modeling power electronics and interfacing energy conversion systems
Simões, Marcelo Godoy
2017-01-01
Discusses the application of mathematical and engineering tools for modeling, simulation and control oriented for energy systems, power electronics and renewable energy. This book builds on the background knowledge of electrical circuits, control of dc/dc converters and inverters, energy conversion and power electronics. The book shows readers how to apply computational methods for multi-domain simulation of energy systems and power electronics engineering problems. Each chapter has a brief introduction on the theoretical background, a description of the problems to be solved, and objectives to be achieved. Block diagrams, electrical circuits, mathematical analysis or computer code are covered. Each chapter concludes with discussions on what should be learned, suggestions for further studies and even some experimental work.
Improving CASINO performance for models with large number of electrons
Energy Technology Data Exchange (ETDEWEB)
Anton, L; Alfe, D; Hood, R Q; Tanqueray, D
2009-05-13
Quantum Monte Carlo calculations have at their core algorithms based on statistical ensembles of multidimensional random walkers which are straightforward to use on parallel computers. Nevertheless some computations have reached the limit of the memory resources for models with more than 1000 electrons because of the need to store a large amount of electronic orbitals related data. Besides that, for systems with large number of electrons, it is interesting to study if the evolution of one configuration of random walkers can be done faster in parallel. We present a comparative study of two ways to solve these problems: (1) distributed orbital data done with MPI or Unix inter-process communication tools, (2) second level parallelism for configuration computation.
Energy Technology Data Exchange (ETDEWEB)
Aggerbeck, L.P.; Peterson, D.L.
1985-02-01
The structure of the small, spherical hepatitis B surface antigen was studied by negative staining, freeze-fracture and freeze-etching electron microscopy and solution X-ray scattering techniques. The protein appears to be organized at the surface into a small number of morphological subunits which display two- and threefold axes of symmetry. The mean particle size was 18.3 nm by negative staining and 19.6 nm by freeze-fracture electron microscopy. The diameter of the individual subunits was about 7.5 nm with an intersubunit distance of about 10.0 nm. The lipid is distributed more homogeneously. Some heterogeneity of the particle structure is apparent which may be due to a slightly variable lipid-protein composition or incomplete or defective particle formation.
Yui, Hiroharu
2010-06-01
Raman scattering spectroscopy can be used to distinguish highly similar molecules and obtain useful information on local physical and chemical environments at their functional group levels. However, obtaining a high-quality Raman spectrum requires high-power excitation and a long acquisition time owing to the inherently small Raman scattering cross section, which is problematic in the analyses of living cells and real-time environmental monitoring. Herein, a new Raman enhancement technique, electron-enhanced Raman scattering (EERS), is described in which artificially generated electrons affect the polarizability of target molecular systems and enhance their inherent Raman cross sections. The EERS technique stands in contrast to the well-known SERS technique, which requires roughened metal surfaces. The history of EERS and its spectroscopic applications to aqueous solutions are presented.
Kusinski, G J; Jokisaari, J R; Noriega, R; Goris, L; Donovan, M; Salleo, A
2010-03-01
A solution-based chemistry was used to synthesize intrinsic and Al-doped (1% and 5% nominal atomic concentration of Al) ZnO nanostructures. The nanowires were grown at 300 degrees C in trioctylamine by dissolving Zn acetate and Al acetate. Different doping conditions gave rise to different nanoscale morphologies. The effect of a surfactant (oleic acid) was also investigated. An electron microscopy study correlating morphology, aspect ratio and doping of the individual ZnO wires to the electrical properties of the spin coated films is presented. HRTEM revealed single crystalline [0001] wires.
Ganguly, Moumita; Chakraborty, Aniruddha
2017-10-01
A diffusion theory for intramolecular reactions of polymer chain in dilute solution is formulated. We give a detailed analytical expression for calculation of rate of polymer looping in solution. The physical problem of looping can be modeled mathematically with the use of a Smoluchowski-like equation with a Dirac delta function sink of finite strength. The solution of this equation is expressed in terms of Laplace Transform of the Green's function for end-to-end motion of the polymer in absence of the sink. We have defined two different rate constants, the long term rate constant and the average rate constant. The average rate constant and long term rate constant varies with several parameters such as length of the polymer (N), bond length (b) and the relaxation time τR. The long term rate constant is independent of the initial probability distribution.
Model of convection mass transfer in titanium alloy at low energy high current electron beam action
Sarychev, V. D.; Granovskii, A. Yu; Nevskii, S. A.; Konovalov, S. V.; Gromov, V. E.
2017-01-01
The convection mixing model is proposed for low-energy high-current electron beam treatment of titanium alloys, pre-processed by heterogeneous plasma flows generated via explosion of carbon tape and powder TiB2. The model is based on the assumption vortices in the molten layer are formed due to the treatment by concentrated energy flows. These vortices evolve as the result of thermocapillary convection, arising because of the temperature gradient. The calculation of temperature gradient and penetration depth required solution of the heat problem with taking into account the surface evaporation. However, instead of the direct heat source the boundary conditions in phase transitions were changed in the thermal conductivity equation, assuming the evaporated material takes part in the heat exchange. The data on the penetration depth and temperature distribution are used for the thermocapillary model. The thermocapillary model embraces Navier-Stocks and convection heat transfer equations, as well as the boundary conditions with the outflow of evaporated material included. The solution of these equations by finite elements methods pointed at formation of a multi-vortices structure when electron-beam treatment and its expansion over new zones of material. As the result, strengthening particles are found at the depth exceeding manifold their penetration depth in terms of the diffusion mechanism.
Directory of Open Access Journals (Sweden)
Monier-Vinard Eric
2013-01-01
Full Text Available The recent Printed Wiring Board embedding technology is an attractive packaging alternative that allows a very high degree of miniaturization by stacking multiple layers of embedded chips. This disruptive technology will further increase the thermal management challenges by concentrating heat dissipation at the heart of the organic substrate structure. In order to allow the electronic designer to early analyze the limits of the power dissipation, depending on the embedded chip location inside the board, as well as the thermal interactions with other buried chips or surface mounted electronic components, an analytical thermal modelling approach was established. The presented work describes the comparison of the analytical model results with the numerical models of various embedded chips configurations. The thermal behaviour predictions of the analytical model, found to be within ±10% of relative error, demonstrate its relevance for modelling high density electronic board. Besides the approach promotes a practical solution to study the potential gain to conduct a part of heat flow from the components towards a set of localized cooled board pads.
Investigating conceptual models for physical property couplings in solid solution models of cement
Energy Technology Data Exchange (ETDEWEB)
Benbow, Steven; Watson, Claire; Savage, David [Quintesssa Ltd., Henley-on-Thames (United Kingdom)
2005-11-15
The long-term behaviour of cementitious engineered barriers is an important process to consider when modelling the migration of radionuclides from a geological repository for nuclear waste. The modelling of cement is complicated by the fact that the cement is dominated by the behaviour of calcium silicate hydrate (CSH) gel which is a complex solid exhibiting incongruent dissolution behaviour. In this report, we have demonstrated the implementation of a solid-solution CSH gel model within a geochemical transport modelling framework using the Raiden computer code to investigate cement/concrete-groundwater interactions. The modelling conducted here shows that it is possible to couple various conceptual models for the evolution of physical properties of concrete with a solid solution model for cement degradation in a fully coupled geochemical transport model to describe the interaction of cement/concrete engineered barriers with groundwater. The results show that changes to the conceptual models and flow rates can give rise to very different evolutions. Most simulations were carried out at a reduced 'experimental' scale rather than full repository scale. The work has shown the possibility to investigate also the changing physical properties of degrading cement. To further develop the model more emphasis is needed on kinetics and the detailed development of a nearly clogged pore space. Modelling of the full repository scale could be another way forward to understand the behaviour of degrading concrete. A general conclusion is that the combined effects of chemical evolution and physical degradation should be analysed in performance assessments of cementitious repositories. Moreover, the project results will be used as one basis in coming reviews of SKB's safety assessments of repositories for spent fuel and low-and intermediate level waste.
Institute of Scientific and Technical Information of China (English)
无
2006-01-01
Sub-microsecond time-resolved absorption spectroscopy has been used to study the electronically excited state behavior of soluble multiwalled carbon nanotube (MWNTsCON((CH2)9- CH3)2, denoted as MDDA) in chloroform, toluene and cyclohexane. Following pulsed photo-excitation of MDDA at 355 nm, three major spectral components are clearly identified with the help of global analysis carried out over 7 representative kinetics curves from 450 to 700 nm. The solvent dependence of decay associated difference spectra (DADS) and the corresponding lifetimes help to assign these transient species to singlet state (S1), triplet state (T1) and charge-separated state (CS), respectively. Preliminary discussion had been made to explore the involved photophysical and electron transfer processes.
Application of transmission electron tomography for modeling the renal corpuscle.
Cheng, Delfine; Shen, Sylvie; Chen, Xin-Ming; Pollock, Carol; Braet, Filip
2013-11-01
Structural alteration to the microanatomical organization of the glomerular filtration barrier results in proteinuria. Conventional transmission electron microscopy is an important diagnostic tool to assess the degree of ultrastructural damage of the corpusclar filtration unit. However, this approach lacks the ability to collect accurate stereological insights in a relative large tissue volume. Transmission electron tomography offers the ability to gather three-dimensional information with relative ease. Therefore, this contribution aims to highlight what electron tomography can bring to the pathologist in this challenging area of diagnostic practice. Kidney tissue was prepared for routine ultrastructural transmission electron microscopy investigation. Three-dimensional data stacks were automatically acquired by tilting semi-thin sections of 270 nm in an angular range of typically -60° to +60° with 1° increment. Subsequently, models of the filtration unit were produced by computer-assisted tracking of structures of interest. This short report illustrates the capability that transmission electron tomography can offer in the fine structure-function assessment of the porous fenestrated glomerular capillary endothelium, the underlying basement membrane and the podocyte filtration slits. Furthermore, this approach allows the generation of morphometric data about size, shape and volume alterations of the kidney's filtration barrier at the nanoscale.
Optics solutions for pp operation with electron lenses at 100 GeV
Energy Technology Data Exchange (ETDEWEB)
White, S. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Fischer, W. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Luo, Y. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.
2014-07-12
Electron lenses for head-on compensation are currently under commissioning and foreseen to be operational for the 2015 polarized proton run. These devices will provide a partial compensation of head-on beam-beam effects and allow to double the RHIC proton luminosity. This note reviews the optics constraints related to beam-beam compensation and summarizes the current lattice options for proton operation at 100 GeV.
Energy Technology Data Exchange (ETDEWEB)
Song Meirong, E-mail: smr770505@yahoo.com.cn [College of Sciences, Henan Agricultural University, Zhengzhou 450002 (China); Song Junling [School of Food, Henan Institute of Science and Technology, Xinxiang, 453003 (China); Ning Aimin [College of Sciences, Henan Agricultural University, Zhengzhou 450002 (China); Cui Baoan, E-mail: baoancui@henau.edu.cn [College of Sciences, Henan Agricultural University, Zhengzhou 450002 (China); Cui Shumin; Zhou Yaobing; An Wankai; Dong Xuesong; Zhang Gege [College of Sciences, Henan Agricultural University, Zhengzhou 450002 (China)
2010-01-01
The aim of this study was to determine the feasibility of using silica sol to carry a hydrophobic drug in aqueous solution. Enrofloxacin, which was selected as the model drug because it is a broad-spectrum antibiotic drug with poor solubility in water, was adsorbed onto silica sol in aqueous solution during cooling from 60 deg. C to room temperature. The drug-loaded silica sol was characterized by transmission electron microscopy, Fourier transform infrared spectrum, thermal gravimetric analysis and ultraviolet-visible light spectroscopy. The results showed that enrofloxacin was adsorbed by silica sol without degradation at a loading of 15.23 wt.%. In contrast to the rapid release from pure enrofloxacin, the drug-loaded silica sol showed a slower release over a longer time. Kinetics analysis suggested the drug release from silica sol was mainly a diffusion-controlled process. Therefore, silica sol can be used to carry a hydrophobic drug in aqueous solution for controlled drug delivery.
A Framework to Implement IoT Network Performance Modelling Techniques for Network Solution Selection
Directory of Open Access Journals (Sweden)
Declan T. Delaney
2016-12-01
Full Text Available No single network solution for Internet of Things (IoT networks can provide the required level of Quality of Service (QoS for all applications in all environments. This leads to an increasing number of solutions created to fit particular scenarios. Given the increasing number and complexity of solutions available, it becomes difficult for an application developer to choose the solution which is best suited for an application. This article introduces a framework which autonomously chooses the best solution for the application given the current deployed environment. The framework utilises a performance model to predict the expected performance of a particular solution in a given environment. The framework can then choose an apt solution for the application from a set of available solutions. This article presents the framework with a set of models built using data collected from simulation. The modelling technique can determine with up to 85% accuracy the solution which performs the best for a particular performance metric given a set of solutions. The article highlights the fractured and disjointed practice currently in place for examining and comparing communication solutions and aims to open a discussion on harmonising testing procedures so that different solutions can be directly compared and offers a framework to achieve this within IoT networks.
Delaney, Declan T; O'Hare, Gregory M P
2016-12-01
No single network solution for Internet of Things (IoT) networks can provide the required level of Quality of Service (QoS) for all applications in all environments. This leads to an increasing number of solutions created to fit particular scenarios. Given the increasing number and complexity of solutions available, it becomes difficult for an application developer to choose the solution which is best suited for an application. This article introduces a framework which autonomously chooses the best solution for the application given the current deployed environment. The framework utilises a performance model to predict the expected performance of a particular solution in a given environment. The framework can then choose an apt solution for the application from a set of available solutions. This article presents the framework with a set of models built using data collected from simulation. The modelling technique can determine with up to 85% accuracy the solution which performs the best for a particular performance metric given a set of solutions. The article highlights the fractured and disjointed practice currently in place for examining and comparing communication solutions and aims to open a discussion on harmonising testing procedures so that different solutions can be directly compared and offers a framework to achieve this within IoT networks.
Delaney, Declan T.; O’Hare, Gregory M. P.
2016-01-01
No single network solution for Internet of Things (IoT) networks can provide the required level of Quality of Service (QoS) for all applications in all environments. This leads to an increasing number of solutions created to fit particular scenarios. Given the increasing number and complexity of solutions available, it becomes difficult for an application developer to choose the solution which is best suited for an application. This article introduces a framework which autonomously chooses the best solution for the application given the current deployed environment. The framework utilises a performance model to predict the expected performance of a particular solution in a given environment. The framework can then choose an apt solution for the application from a set of available solutions. This article presents the framework with a set of models built using data collected from simulation. The modelling technique can determine with up to 85% accuracy the solution which performs the best for a particular performance metric given a set of solutions. The article highlights the fractured and disjointed practice currently in place for examining and comparing communication solutions and aims to open a discussion on harmonising testing procedures so that different solutions can be directly compared and offers a framework to achieve this within IoT networks. PMID:27916929
Power electronic converters modeling and control with case studies
Bacha, Seddik; Bratcu, Antoneta Iuliana
2014-01-01
Modern power electronic converters are involved in a very broad spectrum of applications: switched-mode power supplies, electrical-machine-motion-control, active power filters, distributed power generation, flexible AC transmission systems, renewable energy conversion systems and vehicular technology, among them. Power Electronics Converters Modeling and Control teaches the reader how to analyze and model the behavior of converters and so to improve their design and control. Dealing with a set of confirmed algorithms specifically developed for use with power converters, this text is in two parts: models and control methods. The first is a detailed exposition of the most usual power converter models: · switched and averaged models; · small/large-signal models; and · time/frequency models. The second focuses on three groups of control methods: · linear control approaches normally associated with power converters; · resonant controllers b...
MATHEMATICAL MODELING OF EXTRACELLULAR ELECTRON TRANSFER IN BIOFILMS
Energy Technology Data Exchange (ETDEWEB)
Renslow, Ryan S.; Babauta, Jerome T.; Kuprat, Andrew P.; Schenk, Jim; Ivory, Cornelius; Fredrickson, Jim K.; Beyenal, Haluk
2015-09-12
Electrochemically active biofilms have a unique form of respiration in which they utilize solid external materials as terminal electron acceptors for their metabolism. Currently, two primary mechanisms have been identified for long-range extracellular electron transfer (EET): a diffusion- and a conduction-based mechanism. Evidence in the literature suggests that some biofilms, particularly Shewanella oneidensis, produce the requisite components for both mechanisms. In this study, a generic model is presented that incorporates the diffusion- and the conduction-based mechanisms and allows electrochemically active biofilms to utilize both simultaneously. The model was applied to S. oneidensis and Geobacter sulfurreducens biofilms using experimentally generated data found in the literature. Our simulation results show that 1) biofilms having both mechanisms available, especially if they can interact, may have a metabolic advantage over biofilms that can use only a single mechanism; 2) the thickness of G. sulfurreducens biofilms is likely not limited by conductivity; 3) accurate intrabiofilm diffusion coefficient values are critical for current generation predictions; and 4) the local biofilm potential and redox potential are two distinct parameters and cannot be assumed to have identical values. Finally, we determined that simulated cyclic and squarewave voltammetry based on our model are currently not capable of determining the specific percentages of extracellular electron transfer mechanisms in a biofilm. The developed model will be a critical tool for designing experiments to explain EET mechanisms.
Modeling biofilms with dual extracellular electron transfer mechanisms
Renslow, Ryan; Babauta, Jerome; Kuprat, Andrew; Schenk, Jim; Ivory, Cornelius; Fredrickson, Jim; Beyenal, Haluk
2013-01-01
Electrochemically active biofilms have a unique form of respiration in which they utilize solid external materials as terminal electron acceptors for their metabolism. Currently, two primary mechanisms have been identified for long-range extracellular electron transfer (EET): a diffusion- and a conduction-based mechanism. Evidence in the literature suggests that some biofilms, particularly Shewanella oneidensis, produce the requisite components for both mechanisms. In this study, a generic model is presented that incorporates the diffusion- and the conduction-based mechanisms and allows electrochemically active biofilms to utilize both simultaneously. The model was applied to S. oneidensis and Geobacter sulfurreducens biofilms using experimentally generated data found in the literature. Our simulation results show that 1) biofilms having both mechanisms available, especially if they can interact, may have a metabolic advantage over biofilms that can use only a single mechanism; 2) the thickness of G. sulfurreducens biofilms is likely not limited by conductivity; 3) accurate intrabiofilm diffusion coefficient values are critical for current generation predictions; and 4) the local biofilm potential and redox potential are two distinct parameters and cannot be assumed to have identical values. Finally, we determined that simulated cyclic and squarewave voltammetry based on our model are currently not capable of determining the specific percentages of extracellular electron transfer mechanisms in a biofilm. The developed model will be a critical tool for designing experiments to explain EET mechanisms. PMID:24113651
Contractual Solutions in Electronic Publishing Industry: A Comparative study of License Agreements
Directory of Open Access Journals (Sweden)
K.T. Anuradha
2005-10-01
Full Text Available Information Technology (IT revolution has brought global change and has impact on electronic publishing industry also. In the digital and networked environment, publishers are concerned about protecting their products from illegal use. Copyright has been proclaimed as an important weapon by the publishers to safeguard their products. In view of the increasing importance that is gained by contract law in electronic publishing, more and more libraries are engaged in signing License Agreements for getting access to all types of electronic information products. It has become imperative on the part of librarians to have knowledge of License agreements and their clauses. The body of the license agreements differs from publisher to publisher and is product dependent too. Since there is a difference between the license agreements of societal publishers and commercial publishers, an attempt is made here to carry out a comparative study of the clauses of the license agreements among commercial publishers at the first level and societal publishers at the second level. It is observed that the licensors’ rights are well protected compared to that of licensees’ rights.
Three-Dimensional Electron Optics Model Developed for Traveling-Wave Tubes
Kory, Carol L.
2000-01-01
A three-dimensional traveling-wave tube (TWT) electron beam optics model including periodic permanent magnet (PPM) focusing has been developed at the NASA Glenn Research Center at Lewis Field. This accurate model allows a TWT designer to develop a focusing structure while reducing the expensive and time-consuming task of building the TWT and hot-testing it (with the electron beam). In addition, the model allows, for the first time, an investigation of the effect on TWT operation of the important azimuthally asymmetric features of the focusing stack. The TWT is a vacuum device that amplifies signals by transferring energy from an electron beam to a radiofrequency (RF) signal. A critically important component is the focusing structure, which keeps the electron beam from diverging and intercepting the RF slow wave circuit. Such an interception can result in excessive circuit heating and decreased efficiency, whereas excessive growth in the beam diameter can lead to backward wave oscillations and premature saturation, indicating a serious reduction in tube performance. The most commonly used focusing structure is the PPM stack, which consists of a sequence of cylindrical iron pole pieces and opposite-polarity magnets. Typically, two-dimensional electron optics codes are used in the design of magnetic focusing devices. In general, these codes track the beam from the gun downstream by solving equations of motion for the electron beam in static-electric and magnetic fields in an azimuthally symmetric structure. Because these two-dimensional codes cannot adequately simulate a number of important effects, the simulation code MAFIA (solution of Maxwell's equations by the Finite-Integration-Algorithm) was used at Glenn to develop a three-dimensional electron optics model. First, a PPM stack was modeled in three dimensions. Then, the fields obtained using the magnetostatic solver were loaded into a particle-in-cell solver where the fully three-dimensional behavior of the beam
The Lunar Internal Structure Model: Problems and Solutions
Nefedyev, Yuri; Gusev, Alexander; Petrova, Natalia; Varaksina, Natalia
decomposition of gravitational field of the Moon of members up to 165th order with a high degree of accuracy. Judging from the given data, the distinctive feature of the Moon’s gravitational field is that harmonics of the third and even the fourth order are comparable with harmonics of the second order, except for member J2. General conclusion: according to recent data, the true figure of the Moon is much more complex than a three-axis ellipsoid. Gravitational field and dynamic figure of the multilayered Moon: One of the main goals of selenodesy is the study of a dynamic figure of the Moon which determines distribution of the mass within the Moon’s body. A dynamic figure is shaped by the inertia ellipsoid set by values of resultant moments of inertia of the Moon A, B, C and their orientation in space. Selenoid satellites (SS) open new and most perspective opportunities in the study of gravitational field and the Moon’s figure. SSs “Moon 10”, “Apollo”, “Clementine”, “Lunar Prospector” trajectory tracking data processing has allowed for identification of coefficients in decomposition of gravitational field of the Moon of members up to 165th order with a high degree of accuracy. Judging from the given data, the distinctive feature of the Moon’s gravitational field is that harmonics of the third and even the fourth order are comparable with harmonics of the second order. Difference from zero of c-coefficients proves asymmetry of gravitational fields on the visible and invisible sides of the Moon. As a first attempt at solving the problem, the report presents the survey of internal structure of the Moon, tabulated values of geophysical parameters and geophysical profile of the Moon, including liquid lunar core, analytical solution of Clairaut’s equation for the two-layer model of the Moon; mathematical and bifurcational analysis of solution based on physically justified task options; original debugged software in VBA programming language for computer
Modeling and multidimensional optimization of a tapered free electron laser
Directory of Open Access Journals (Sweden)
Y. Jiao
2012-05-01
Full Text Available Energy extraction efficiency of a free electron laser (FEL can be greatly increased using a tapered undulator and self-seeding. However, the extraction rate is limited by various effects that eventually lead to saturation of the peak intensity and power. To better understand these effects, we develop a model extending the Kroll-Morton-Rosenbluth, one-dimensional theory to include the physics of diffraction, optical guiding, and radially resolved particle trapping. The predictions of the model agree well with that of the GENESIS single-frequency numerical simulations. In particular, we discuss the evolution of the electron-radiation interaction along the tapered undulator and show that the decreasing of refractive guiding is the major cause of the efficiency reduction, particle detrapping, and then saturation of the radiation power. With this understanding, we develop a multidimensional optimization scheme based on GENESIS simulations to increase the energy extraction efficiency via an improved taper profile and variation in electron beam radius. We present optimization results for hard x-ray tapered FELs, and the dependence of the maximum extractable radiation power on various parameters of the initial electron beam, radiation field, and the undulator system. We also study the effect of the sideband growth in a tapered FEL. Such growth induces increased particle detrapping and thus decreased refractive guiding that together strongly limit the overall energy extraction efficiency.
Goldstein, Sara; Behar, David; Rajh, Tijana; Rabani, Joseph
2016-04-21
The mechanism of nitrite reduction by excess electrons on TiO2 nanoparticles (eTiO2(-)) was studied under anaerobic conditions. TiO2 was loaded with up to 75 electrons per particle, induced by γ-irradiation of acidic TiO2 colloid solutions containing 2-propanol. Time-resolved kinetics and material analysis were performed, mostly at 1.66 g L(-1) TiO2. At relatively low nitrite concentrations (R = [eTiO2(-)]o/[nitrite]o > 1.5), eTiO2(-) decays via two consecutive processes; at higher concentrations, only one decay step is observed. The stoichiometric ratio Δ[eTiO2(-)]/[nitrite]o of the faster process is about 2. This process involves the one-electron reduction of nitrite, forming the nitrite radical (k1 = (2.0 ± 0.2) × 10(6) M(-1) s(-1)), which further reacts with eTiO2(-) (k2) in competition with its dehydration to nitric oxide (NO) (k3). The ratios k2/k3 = (3.0 ± 0.5) × 10(3) M(-1) and k2 > 1 × 10(6) M(-1) s(-1) were derived from kinetic simulations and product analysis. The major product of this process is NO. The slower stage of the kinetics involves the reduction of NO by eTiO2(-), and the detailed mechanism of this process has been discussed in our earlier publication. The results reported in this study suggest that several intermediates, including NO and NH2OH, are adsorbed on the titanium nanoparticles and give rise to inverse dependency of the respective reaction rates on the TiO2 concentration. It is demonstrated that the reduction of nitrite by eTiO2(-) yields mainly N2O and NH3 via consecutive one-electron transfer reactions.
Nonperturbative contributions from complexified solutions in C PN -1 models
Fujimori, Toshiaki; Kamata, Syo; Misumi, Tatsuhiro; Nitta, Muneto; Sakai, Norisuke
2016-11-01
We discuss the nonperturbative contributions from real and complex saddle point solutions in the C P1 quantum mechanics with fermionic degrees of freedom, using the Lefschetz thimble formalism beyond the Gaussian approximation. We find bion solutions, which correspond to (complexified) instanton-anti-instanton configurations stabilized in the presence of the fermionic degrees of freedom. By computing the one-loop determinants in the bion backgrounds, we obtain the leading order contributions from both the real and complex bion solutions. To incorporate quasizero modes which become nearly massless in a weak coupling limit, we regard the bion solutions as well-separated instanton-anti-instanton configurations and calculate a complexified quasimoduli integral based on the Lefschetz thimble formalism. The nonperturbative contributions from the real and complex bions are shown to cancel out in the supersymmetric case and give an (expected) ambiguity in the nonsupersymmetric case, which plays a vital role in the resurgent trans-series. For nearly supersymmetric situations, evaluation of the Lefschetz thimble gives results in precise agreement with those of the direct evaluation of the Schrödinger equation. We also perform the same analysis for the sine-Gordon quantum mechanics and point out some important differences showing that the sine-Gordon quantum mechanics does not correctly describe the 1d limit of the C PN -1 field theory of R ×S1.
Walker, R. D., Jr.
1973-01-01
Results of experiments on electron microscopy of fuel cell components, thermal decomposition of Teflon by thermogravimetry, surface area and pore size distribution measurements, water transport in fuel cells, and surface tension of KOH solutions are described.
On periodic solutions of Goodwin's business cycle model with only floor in induced investment
Antonova, A. O.; Reznik, S. N.; Todorov, M. D.
2013-10-01
We present here an analytical solution of Goodwin's business cycle model in the form of delay differential equation with fixed delay θ and piecewise linear accelerator with only the floor (or the ceiling). We conclude that in this model the time behavior of the solution similar to Goodwin's limit cycle is not possible. These solution looks similar to the oscillation with a period θ, the amplitude of the oscillation growing exponentially to infinity as t →∞. The conditions for existence of the periodic solution in Goodwin's model with fixed delay for the nonlinear accelerator are also discussed.
Golosov, D. I.
2013-03-01
We consider a spinless extended Falicov--Kimball model at half-filling, for the case of opposite-parity bands. Within the Hartree--Fock approach, we calculate the excitation energies in the chiral phase, which is a possible mean-field solution in the presence of a hybridisation. It is shown that the chiral phase is unstable. We then briefly review the accumulated results on stability and degeneracies of the excitonic insulator phase. Based on these, we conclude that the presence of both hybridisation and narrow-band hopping is required for electronic ferroelectricity.
Rocha, Frederico AE; Lourenço, Nuno CC; Horta, Nuno CG
2013-01-01
This book applies to the scientific area of electronic design automation (EDA) and addresses the automatic sizing of analog integrated circuits (ICs). Particularly, this book presents an approach to enhance a state-of-the-art layout-aware circuit-level optimizer (GENOM-POF), by embedding statistical knowledge from an automatically generated gradient model into the multi-objective multi-constraint optimization kernel based on the NSGA-II algorithm. The results showed allow the designer to explore the different trade-offs of the solution space, both through the achieved device sizes, or the resp
Rosenbaum, J. S.
1971-01-01
Systems of ordinary differential equations in which the magnitudes of the eigenvalues (or time constants) vary greatly are commonly called stiff. Such systems of equations arise in nuclear reactor kinetics, the flow of chemically reacting gas, dynamics, control theory, circuit analysis and other fields. The research reported develops an A-stable numerical integration technique for solving stiff systems of ordinary differential equations. The method, which is called the generalized trapezoidal rule, is a modification of the trapezoidal rule. However, the method is computationally more efficient than the trapezoidal rule when the solution of the almost-discontinuous segments is being calculated.
Avila Ferrer, Francisco José; Improta, Roberto; Santoro, Fabrizio; Barone, Vincenzo
2011-10-14
Starting from Marcus's relationship connecting the inhomogeneous broadening with the solvent reorganization energy and exploiting recent state-specific developments in PCM/TD-DFT calculations, we propose a procedure to estimate the polar broadening of optical transitions. When applied to two representative molecular probes, coumarin C153 and 4-aminophthalimide, in different solvents, our approach provides for the polar broadening values fully consistent with the experimental ones. Thanks to these achievements, for the first time fully ab initio vibrationally resolved absorption spectra in solution are computed, obtaining spectra for coumarin C153 in remarkable agreement with experiments.
A model for hypermedia learning environments based on electronic books
Directory of Open Access Journals (Sweden)
Ignacio Aedo
1997-12-01
Full Text Available Current hypermedia learning environments do not have a common development basis. Their designers have often used ad-hoc solutions to solve the learning problems they have encountered. However, hypermedia technology can take advantage of employing a theoretical scheme - a model - which takes into account various kinds of learning activities, and solves some of the problems associated with its use in the learning process. The model can provide designers with the tools for creating a hypermedia learning system, by allowing the elements and functions involved in the definition of a specific application to be formally represented.
Quantitative model studies for interfaces in organic electronic devices
Gottfried, J. Michael
2016-11-01
In organic light-emitting diodes and similar devices, organic semiconductors are typically contacted by metal electrodes. Because the resulting metal/organic interfaces have a large impact on the performance of these devices, their quantitative understanding is indispensable for the further rational development of organic electronics. A study by Kröger et al (2016 New J. Phys. 18 113022) of an important single-crystal based model interface provides detailed insight into its geometric and electronic structure and delivers valuable benchmark data for computational studies. In view of the differences between typical surface-science model systems and real devices, a ‘materials gap’ is identified that needs to be addressed by future research to make the knowledge obtained from fundamental studies even more beneficial for real-world applications.
Access Control Model for Sharing Composite Electronic Health Records
Jin, Jing; Ahn, Gail-Joon; Covington, Michael J.; Zhang, Xinwen
The adoption of electronically formatted medical records, so called Electronic Health Records (EHRs), has become extremely important in healthcare systems to enable the exchange of medical information among stakeholders. An EHR generally consists of data with different types and sensitivity degrees which must be selectively shared based on the need-to-know principle. Security mechanisms are required to guarantee that only authorized users have access to specific portions of such critical record for legitimate purposes. In this paper, we propose a novel approach for modelling access control scheme for composite EHRs. Our model formulates the semantics and structural composition of an EHR document, from which we introduce a notion of authorized zones of the composite EHR at different granularity levels, taking into consideration of several important criteria such as data types, intended purposes and information sensitivities.
Modeling Crabbing Dynamics in an Electron-Ion Collider
Energy Technology Data Exchange (ETDEWEB)
Castilla, Alejandro [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Old Dominion Univ., Norfolk, VA (United States); Univ. de Guanajuato (DCI-UG), Leon (Mexico); Morozov, Vasiliy S. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Satogata, Todd J. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Old Dominion Univ., Norfolk, VA (United States); Delayen, Jean R. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Old Dominion Univ., Norfolk, VA (United States)
2015-09-01
A local crabbing scheme requires π/2 (mod π) horizontal betatron phase advances from an interaction point (IP) to the crab cavities on each side of it. However, realistic phase advances generated by sets of quadrupoles, or Final Focusing Blocks (FFB), between the crab cavities located in the expanded beam regions and the IP differ slightly from π/2. To understand the effect of crabbing on the beam dynamics in this case, a simple model of the optics of the Medium Energy Electron-Ion Collider (MEIC) including local crabbing was developed using linear matrices and then studied numerically over multiple turns (1000 passes) of both electron and proton bunches. The same model was applied to both local and global crabbing schemes to determine the linear-order dynamical effects of the synchro-betatron coupling induced by crabbing.
Modeling of carbon dioxide absorption by aqueous ammonia solutions using the Extended UNIQUAC model
DEFF Research Database (Denmark)
Darde, Victor Camille Alfred; van Well, Willy J. M.; Stenby, Erling Halfdan
2010-01-01
and the concentration range up to 80 molal ammonia. In this work, the validity of this model was extended up to 150°C and the accuracy improved by increasing the number of experimental data points from 2000 to more than 3500. These experimental data consisting of vapor-liquid equilibrium data in various concentration...... ranges, enthalpy change from partial evaporation measurements, speciation data, heat capacity, enthalpy of solution and enthalpy of dilution data have been used to refit 43 model parameters and standard state properties. Henry’s law constant correlations have been used for extrapolating standard state...
Variability of Protein Structure Models from Electron Microscopy.
Monroe, Lyman; Terashi, Genki; Kihara, Daisuke
2017-03-02
An increasing number of biomolecular structures are solved by electron microscopy (EM). However, the quality of structure models determined from EM maps vary substantially. To understand to what extent structure models are supported by information embedded in EM maps, we used two computational structure refinement methods to examine how much structures can be refined using a dataset of 49 maps with accompanying structure models. The extent of structure modification as well as the disagreement between refinement models produced by the two computational methods scaled inversely with the global and the local map resolutions. A general quantitative estimation of deviations of structures for particular map resolutions are provided. Our results indicate that the observed discrepancy between the deposited map and the refined models is due to the lack of structural information present in EM maps and thus these annotations must be used with caution for further applications.
MODEL PSEUDOPOTENTIAL OF THE ELECTRON - NEGATIVE ION INTERACTION
Directory of Open Access Journals (Sweden)
Yu.Rudavskii
2003-01-01
Full Text Available Generalization of the Anderson model to describe the states of electronegative impurities in liquid-metal alloys is the main aim of the present paper. The effects of the random inner field on the charge impurity states is accounted for selfconsistently. Qualitative and quantitative estimation of hamiltonian parameters has been carried out. The limits of the proposed model applicability to a description of real systems are considered. Especially, the case of the oxygen impurity in liquid sodium is studied. The modelling of the proper electron-ionic interaction potential is the main goal of the paper. The parameters of the proposed pseudopotential are analyzed in detail. The comparison with other model potentials have been carried out. Resistivity of liquid sodium containing the oxygen impurities is calculated with utilizing the form-factor of the proposed model potential. Dependence of the resistivity on impurity concentration and on the charge states is received.
$\\psi$ = W e$^{\\pm\\phi}$ quantum cosmological solutions for Class A Bianchi models
Obregón, O
1995-01-01
We find solutions for quantum Class A Bianchi models of the form \\rm \\Psi=W\\, e^{\\pm \\Phi} generalizing the results obtained by Moncrief and Ryan in standard quantum cosmology. For the II and IX Bianchi models there are other solutions \\rm \\tilde\\Phi_2, \\rm \\tilde\\Phi_9 to the Hamilton-Jacobi equation for which \\rm \\Psi is necessarely zero, in contrast with solutions found in supersymmetric quantum cosmology.
Exact Shock Solution of a Coupled System of Delay Differential Equations: A Car-Following Model
Tutiya, Yohei; Kanai, Masahiro
2007-08-01
In this letter, we present exact shock solutions of a coupled system of delay differential equations, which was introduced as a traffic-flow model called car-following model. We use the Hirota method, originally developed in order to solve soliton equations. The relevant delay differential equations have been known to allow exact solutions expressed by elliptic functions with periodic boundary conditions. In the present work, however, shock solutions are obtained with open boundaries, representing the stationary propagation of a traffic jam.
AUTO-DARBOUX TRANSFORMATION AND EXACT SOLUTIONS OF THE BRUSSELATOR REACTION DIFFUSION MODEL
Institute of Scientific and Technical Information of China (English)
闫振亚; 张鸿庆
2001-01-01
Firstly, using the improved homogeneous balance method, an auto-Darboux transformation (ADT) for the Brusselator reaction diffusion model is found. Based on the ADT, several exact solutions are obtained which contain some authors' results known.Secondly, by using a series of transformations, the model is reduced into a nonlinear reaction diffusion equation and then through using sine- cosine method, more exact solutions are found which contain soliton solutions.