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Articles 29071 - 29100 of 34204

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Charged Particles And Neutral Kaons In Photoproduced Jets At Hera, J. Breitweg, M. Derrick, D. Krakauer, S. Magill, D. Mikunas, B. Musgrave, J. Repond, R. Stanek, R. L. Talaga, R. Yoshida, H. Zhang, Margarita C. K. Mattingly, F. Anselmo, P. Antonioli, G. Bari, M. Basile, L. Bellagamba, D. Boscherini, A. Bruni, G. Bruni, G. Cara Romeo, G. Castellini, L. Cifarelli, F. Cindolo, A. Contin, M. Corradi, S. De Pasquale, I. Gialas, P. Giusti, G. Iacobucci, G. Laurenti Jan 1998

Charged Particles And Neutral Kaons In Photoproduced Jets At Hera, J. Breitweg, M. Derrick, D. Krakauer, S. Magill, D. Mikunas, B. Musgrave, J. Repond, R. Stanek, R. L. Talaga, R. Yoshida, H. Zhang, Margarita C. K. Mattingly, F. Anselmo, P. Antonioli, G. Bari, M. Basile, L. Bellagamba, D. Boscherini, A. Bruni, G. Bruni, G. Cara Romeo, G. Castellini, L. Cifarelli, F. Cindolo, A. Contin, M. Corradi, S. De Pasquale, I. Gialas, P. Giusti, G. Iacobucci, G. Laurenti

Faculty Publications

Charged particles (h±) and K0 mesons have been studied in photoproduced events containing at least one jet of ET > 8 GeV n a pseudorapidity interval (-0.5, 0.5) in the ZEUS laboratory frame. Distributions are presented in terms of transverse momentum, pseudorapidity and distance of the particle from the axis of a jet. The properties of h± within the jet are described well using the standard settings of PYTHIA, but the use of the multiparton interaction option improves the description outside the jets.

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High-ET Inclusive Jet Cross Sections In Photoproduction At Hera, J. Breitweg, M. Derrick, D. Krakauer, S. Magill, D. Mikunas, B. Musgrave, J. Repond, R. Stanek, R. L. Talaga, R. Yoshida, H. Zhang, Margarita C. K. Mattingly, F. Anselmo, P. Antonioli, G. Bari, M. Basile, L. Bellagamba, D. Boscherini, A. Bruni, G. Bruni, G. Cara Romeo, G. Castellini, L. Cifarelli, F. Cindolo, A. Contin, N. Coppola, M. Corradi, S. De Pasquale, P. Giusti, G. Iacobucci, G. Laurenti Jan 1998

High-ET Inclusive Jet Cross Sections In Photoproduction At Hera, J. Breitweg, M. Derrick, D. Krakauer, S. Magill, D. Mikunas, B. Musgrave, J. Repond, R. Stanek, R. L. Talaga, R. Yoshida, H. Zhang, Margarita C. K. Mattingly, F. Anselmo, P. Antonioli, G. Bari, M. Basile, L. Bellagamba, D. Boscherini, A. Bruni, G. Bruni, G. Cara Romeo, G. Castellini, L. Cifarelli, F. Cindolo, A. Contin, N. Coppola, M. Corradi, S. De Pasquale, P. Giusti, G. Iacobucci, G. Laurenti

Faculty Publications

Inclusive jet differential cross sections for the reaction e+p → e+ + jet + X with quasi-real photons have been measured with the ZEUS detector at HERA. These cross sections are given for the photon-proton centre-of-mass energy interval 134 < W < 277 GeV and jet pseudorapidity in the range -1 < ηjet < 2 in the laboratory frame. The results are presented for three cone radii in the η - φ plane, R = 1.0, 0.7 and 0.5. Measurements of dσ/dηjet above various jet-transverse-energy thresholds up to 25 GeV and in three ranges of W are presented and compared to next-to-leading order (NLO) QCD calculations. For jets defined with R = 1.0 differences between data and NLO calculations are seen at high ηjet and low EjetT. The measured cross sections for jets defined with R = 0.7 are well described by the calculations in the entire measured range ηjet and EjetT. The inclusive jet cross section for EjetT > 21 GeV is consistent with an approximately linear variation with the cone radius R in the range between 0.5 and 1.0, and with NLO calculations.

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Speed Cut-Off Point For Antiforce Waves, Mostafa Hemmati, Mathues Shane Doss, Eric L. George Jan 1998

Speed Cut-Off Point For Antiforce Waves, Mostafa Hemmati, Mathues Shane Doss, Eric L. George

Journal of the Arkansas Academy of Science

A one-dimensional, three-component, fluid model has been employed to investigate the existence of a speed cut-off point for antiforce breakdown waves. The term antiforce wave is used to identify breakdown waves for which the electric field force on electrons is in the opposite direction of wave propagation. The electron fluid-dynamical equations for antiforce waves are different from those of proforce waves. This presentation will address the difference in the set of equations for proforce and antiforce waves and the method of integration of the set of equations through the dynamical transition region for antiforce waves. Also, for antiforce waves, the …

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Applying Binomial Statistics To Weighted Monte Carlo, Sue Ellen Mccloskey, William C. Hall, Wilfred J. Braithwaite Jan 1998

Applying Binomial Statistics To Weighted Monte Carlo, Sue Ellen Mccloskey, William C. Hall, Wilfred J. Braithwaite

Journal of the Arkansas Academy of Science

Weighted Monte Carlo calculations requiring a uniform sampling of the problem-space can suffer from diminished statistical significance because many, if not most, of the randomly-chosen sampling points contribute only slightly to the desired result. Their contribution is reduced in size due the variable-size of the weighting terms. In contrast, none of the randomly-chosen points which are favored by variable size weighting terms will have their statistical significance enhanced beyond that of just one random point in the Monte Carlo sampling. A Monte Carlo analysis was used in earlier work to verify both Gauss' Law and Newton's Shell Theorem. Both examples …

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Microscale And Nanoscale Testing Of Materials Using Scanning Probe Technologies, Mark Phelan Jan 1998

Microscale And Nanoscale Testing Of Materials Using Scanning Probe Technologies, Mark Phelan

Theses

Understanding solid surfaces and their properties is of crucial importance for many sectors of industry. This interest stems from the fact that solid surfaces are the working interface between a solid material and its environment and in many cases it is this interface which determines both the suitability and life span of a mechanical component. Furthermore the modification of surface properties using coatings and multi-layered materials has grown significantly, particularly in the case of data storage, optics and microelectronics. The demands of these and other sectors have provided the impetus for the development of material testing techniques applicable to coatings …

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Emission Of Excimer Radiation From Direct Current, High-Pressure Hollow Cathode Discharge, Ahmed El-Habachi, Karl H. Schoenbach Jan 1998

Emission Of Excimer Radiation From Direct Current, High-Pressure Hollow Cathode Discharge, Ahmed El-Habachi, Karl H. Schoenbach

Bioelectrics Publications

A novel, nonequilibrium, high-pressure, direct current discharge, the microhollow cathode discharge, has been found to be an intense source of xenon and argon excimer radiation peaking at wavelengths of 170 and 130 nm, respectively. In argon discharges with a 100 μm diam hollow cathode, the intensity of the excimer radiation increased by a factor of 5 over the pressure range from 100 to 800 mbar. In xenon discharges, the intensity at 170 nm increased by two orders of magnitude when the pressure was raised from 250 mbar to 1 bar. Sustaining voltages were 200 V for argon and 400 V …

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Solar Cycle Variability Of Hot Oxygen Atoms At Mars, Jhoon Kim, Andrew F. Nagy, Jane L. Fox, Thomas E. Cravens Jan 1998

Solar Cycle Variability Of Hot Oxygen Atoms At Mars, Jhoon Kim, Andrew F. Nagy, Jane L. Fox, Thomas E. Cravens

Physics Faculty Publications

The population of hot oxygen atoms in the Martian exosphere is reexamined using newly calculated hot O production rates for both low and high solar cycle conditions. The hot oxygen production rates are assumed to result from the dissociative recombination of O2+ ions. These calculations take into account the calculated vibrational distribution of O2+ and the new measured branching ratios. Furthermore, these calculations also consider the variation of the dissociative recombination cross section with the relative speed of the participating ions and electrons, the rotational energy of the O2+ ions, and the spread of …

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Attitude Measurement, Mark A. Stedham, Partha P. Banerjee, Seiji Nishifuji, Shogo Tanaka Jan 1998

Attitude Measurement, Mark A. Stedham, Partha P. Banerjee, Seiji Nishifuji, Shogo Tanaka

Electrical and Computer Engineering Faculty Publications

In many practical situations, it is important to determine and measure the attitude of a particular vehicle, such as a ship, an airplane, a piece of mechanical equipment such as a, crane lifter, or a spacecraft. For this reason, many attitude sensors have been developed with advanced computer and semiconductor technologies. This section first introduces the various attitude sensors with an explanation of their operating principles and then presents several methodologies for attitude measurement and determination, including ships and crane lifters, aircraft, and spacecraft applications.

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Correlation Function Formulation For The State Selected Total Reaction Probability, Sophya V. Garashchuk, D. J. Tannor Jan 1998

Correlation Function Formulation For The State Selected Total Reaction Probability, Sophya V. Garashchuk, D. J. Tannor

Faculty Publications

A correlation function formulation for the state-selected total reaction probability, Nα(E), is suggested. A wave packet, correlating with a specific set of internal reactant quantum numbers, α, is propagated forward in time until bifurcation is complete at which time the nonreactive portion of the amplitude is discarded. The autocorrelation function of the remaining amplitude is then computed and Fourier transformed to obtain a reactivity spectrum. Dividing by the corresponding spectrum of the original, unfiltered, wave packet normalizes the reactivity spectrum, yielding the total reaction probability from the internal state, α. The procedure requires negligible storage and just one time-energy Fourier …

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Theoretical Treatment Of Quasibound Resonances In Two-Color Resonant Four-Wave Mixing Spectroscopy, F. Di Teodoro, Elizabeth Mccormack Jan 1998

Theoretical Treatment Of Quasibound Resonances In Two-Color Resonant Four-Wave Mixing Spectroscopy, F. Di Teodoro, Elizabeth Mccormack

Physics Faculty Research and Scholarship

A treatment of continuum states in the application of diagrammatic perturbation theory to calculate the signal produced in two-color resonant four-wave mixing (TC-RFWM) spectroscopy is developed. The third-order susceptibility is significantly modified from that obtained when considering only discrete states. To illustrate the contribution of continuum states, the line profile of a quasibound resonance arising from the configuration interaction of bound and continuum states is derived. Analytic expressions for line profiles are presented for two specific experimental implementations of TC-RFWM used in gas-phase spectroscopic studies. While the TC-RFWM line profiles are found to be very distinct from the line profiles …

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The Eect Of Exposure Time To Clean Room Air On Characteristic Parameters Of Au /Epilayer N-Si Schottky Diodes, M. Sağlam, Ç. Nuhoğlu, E. Ayyildiz, A. Türüt, H.A. Çeti̇nkara Jan 1998

The Eect Of Exposure Time To Clean Room Air On Characteristic Parameters Of Au /Epilayer N-Si Schottky Diodes, M. Sağlam, Ç. Nuhoğlu, E. Ayyildiz, A. Türüt, H.A. Çeti̇nkara

Turkish Journal of Physics

A study has been made on determination and comparison of current-voltage (I-V) and capacitance-voltage (C-V) characteristics parameters of $Au/n-Si$ Schottky barrier diodes (SBDs) with and without thin native oxide layer fabricated on $n$-type $Si$ grown by LPE (Liquid-phase Epitaxy) technique. The native oxide layer with different thicknesses on chemically cleaned on $Si$ surface were obtained by exposing the surfaces to clean room air before evaporating metal. The native oxide thicknesses of samples D2, D3, D4 and D5 are in the form $D2 < D3 < D4 \leq D5$, depending on the exposing time. It has been seen that the values of barrier height $\Phi_b$ of samples D2(0.64 eV), D3(0.66 eV), D4(0.69 eV) and D5(0.69 eV) with the interfacial layer increased with increasing the exposure time and tended to that of the initial sample D1 (nonoxidezed sample, 0.74 eV), and thus also their I-V and C-V curves. The reverse current of sample D1 showed slight nonsaturating behavior. This ''soft'' behavior has been ascribed to the spatial inhomogeneity in the barrier heights at the MS interface. In particular, reverse bias curves of samples D2, D3, D4 and D5 have shown excellent saturation which may be attributed to the passivation of the semiconductor surface states by the native oxide layer which reduces the penetration of the wave functions of electron in the metal into the semiconductor. Especially, the I-V characteristics and experimental parameters of our devices are in agreement with recently reported results revealed by the pulsed surface photovoltage technique for the electronic properties of the HF-treated Si surface during initial oxidation in air.

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Measurement Of The Compton And Coherent Scattering Differential Cross-Sections, Yakup Kurucu, Salih Erzeneoğlu, Rıdvan Durak, Yusuf Şahi̇n Jan 1998

Measurement Of The Compton And Coherent Scattering Differential Cross-Sections, Yakup Kurucu, Salih Erzeneoğlu, Rıdvan Durak, Yusuf Şahi̇n

Turkish Journal of Physics

The total atomic Compton and coherent scattering differential cross section of Al, Sn and Ta for 59.5 keV gamma rays of Am-241 point source have been measured for scattering angles $\theta=81^{\circ}$, $85.5^{\circ}$, $90^{\circ}$ and $94.5^{\circ}$ by a direct method with an energy dispersive x-ray spectrometer. The background correction and detection efficiency are also included the study. The experimental results are comparatively given with some available theoretical data obtained with some approximation methods.

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The Influence Of Solvents On Formation Of The Molecular Geometry Of [{Fe(Salphen)}_2o], Mehmet Kabak, Ayhan Elmali Jan 1998

The Influence Of Solvents On Formation Of The Molecular Geometry Of [{Fe(Salphen)}_2o], Mehmet Kabak, Ayhan Elmali

Turkish Journal of Physics

The crystal structure and magnetic properties of the complex (I)=[$\{$Fe(salphen)$\}_2$\-O]$\cdot$(C$_4$\-H$_8$SO) and (II)=[$\{$Fe(salphen)$\}_2$O]$\cdot$(C$_4$H$_8$O$_2$)\- (salphen H$_2$=N,N'-o-phenylenebis\-(salicylidene-imine)) were recently reported [1, 2]. This complex crystallized with the solvents of dimethyl sulfoxide and dioxane. In this paper, we investigate the influence of the solvents on the formation of the molecular geometry and study the orbital mechanism of the magnetic super-exchange interactions of this complex.

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The Relation Between Dislocation Density And Crystal Crosscut In \Beta-Sn Grown By Modified Bridgman Method, Bahattin Düzgün, İbrahim Karaman, Nazım Uçar Jan 1998

The Relation Between Dislocation Density And Crystal Crosscut In \Beta-Sn Grown By Modified Bridgman Method, Bahattin Düzgün, İbrahim Karaman, Nazım Uçar

Turkish Journal of Physics

Crystals $\beta$-Sn are grown from ingots of 99.99\% purity by modified Bridgman method under $10^{-3}$ torr pressure and oriented by Laue back reflection method. The relation between crystal crosscut and dislocation density calculated using etch hillock technique is investigated. It is found that the dislocation density increases with increasing crystal crosscut.

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A Study Of Events From Si 28 With Emulsion At 4.5 A Gev/C Without Target Fragmentation, A.A. El-Daiem Jan 1998

A Study Of Events From Si 28 With Emulsion At 4.5 A Gev/C Without Target Fragmentation, A.A. El-Daiem

Turkish Journal of Physics

Atotal sample of 1000 inelastic interactions of Si$^{28}$ in emulsion at 4.5 A GeV/c has been used characteristics of projectile fragments. This paper is therefore to devoted to the study of projectile fragments, with special attention to the class of events $n_h$=0, in which the traget nucleus is unwounded. This paper include the multiplicity distributinon and angular distributions of projectile fragments.

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Isotope Effect And Phonon Softening In Superconducting Borocarbides And Boronitrides, Tuğrul Haki̇oğlu, Valery A. Ivanov Jan 1998

Isotope Effect And Phonon Softening In Superconducting Borocarbides And Boronitrides, Tuğrul Haki̇oğlu, Valery A. Ivanov

Turkish Journal of Physics

The isotope effect in the recently disvovered class o superconductors LuNi_2B_2C and La_3Ni_2B_2N_3 is investigated in the context of electron-squezed phonon interaction renormalizing the Ni-d electron-electron correlations. Squeezed phonon mode originates from the anharmonic character of the tetragonal Ni-B structure and is polarized in the vortical direction to the Ni layers. The isotope effect arises as a result of the zero point motion of the Ni-Ni d-electron hopping amplitude dominantly due to this vertical phonon mode. Within this model the isotope exponent is calculated to be \alpha_B \leq 0.20 as compared to the recently found experimental value \alpha_B^{exp} = 0.27 …

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Structural And Optical Characterisation Of Vacuum Deposited Cdte Thin Films, Murat Bayhan Jan 1998

Structural And Optical Characterisation Of Vacuum Deposited Cdte Thin Films, Murat Bayhan

Turkish Journal of Physics

The structural and optical properties of vacuum deposited CdTe thin films on glass substrates were investigated. The effect of the heat treatment in air over the former properties of the layers was also examined. Grain sizes of air heated layers estimated by net broading in the XRD spectra were found to be larger than as-grown layers, confirming that grain growth had occurred during the heat treatment. RHEED patterns of the layers grown at substrate temperatures between 150°C and 170°C had a distinct \{111\} preferred orientation. As-grown CdTe layers were slightly p-type, but highly resistive. Air heat treated layers were p-type …

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The Space-Time Critical Dimension Of An Open Parabosonic String, N. Mebarki & N. Belaloui, M. Haouchine Jan 1998

The Space-Time Critical Dimension Of An Open Parabosonic String, N. Mebarki & N. Belaloui, M. Haouchine

Turkish Journal of Physics

Using analytical properties of a 1-loop open parabosonic M-point transition amplitude, we show that the space-time critical dimension depends on the order of the paraquantization.

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Study Of Emission Parameters Of Ir(Iii)-Ba Film System, F. K. Yusifov, A. K. Orujov Jan 1998

Study Of Emission Parameters Of Ir(Iii)-Ba Film System, F. K. Yusifov, A. K. Orujov

Turkish Journal of Physics

Electrophysical properties of Ir(III)-Ba metal-film system have been studied by thermoionic emission (TE), surface ionization (SI) and thermal desorption spectroscopy (TDS) methods. It has been found that the optimum coverage of barium atoms on iridium (III) face is \theta_{opt} = 0.70 \pm 0.05. The dependence of fractional charge of Richardson constant of Ir(III)-Ba metal-film system on coverage \theta of the Ba atoms in the interval 0 \leq \theta \leq 1 has been experimentally obtained. The dependence of work function of Ir(III)-Ba metal-film system on coverage \theta of Ba atoms has been obtained.

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Bulk Modulus Calculations Of Liquid Alkali Metal Alloys, Mehmet Yilmaz, Seyfeddin Karagözoğlu, İris Gümüş Jan 1998

Bulk Modulus Calculations Of Liquid Alkali Metal Alloys, Mehmet Yilmaz, Seyfeddin Karagözoğlu, İris Gümüş

Turkish Journal of Physics

In this work, the bulk modulus values for liquid alkali metal alloys near melting point are studied in the framework of the Gibbs-Bogoliubov method. We use the local Heine-Abarenkov pseudopotential and Ichimaru-Utsumi screening function in these alloys. The results are compared with experimental and theoretical results.

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Anisotropic Motion Of Lipids In Hydrophobic Core Of Dppc Bilayers. Simulation Of Esr Spectra, Canan Teti̇k, Mustafa Korkmaz Jan 1998

Anisotropic Motion Of Lipids In Hydrophobic Core Of Dppc Bilayers. Simulation Of Esr Spectra, Canan Teti̇k, Mustafa Korkmaz

Turkish Journal of Physics

Planar samples prepared by drying phospholipid dispersions on glass slides provide a convenient model to examine motion and orientation in lipid bilayer structures. In the present work, hydrophobic cores of DPPC multibilayers were studied using a 16-DSA spin label consisting of a nitroxide free radical bonded to the 16 position of stearic acid. This spin label is in great demand for investigation of phase transitions occurring in the hydrophobic cores of lipid multibilayers. Thus, its room temperature motional and orientational features in phospholipid bilayers must be known accurately to avoid any misinterpretation in using it in these types of studies. …

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Statistics And Size-Quantized Anisotropy Of Electron States In N-Ge And N-Si Films, Bahshali Kuliev, Vugar Gadjiev Jan 1998

Statistics And Size-Quantized Anisotropy Of Electron States In N-Ge And N-Si Films, Bahshali Kuliev, Vugar Gadjiev

Turkish Journal of Physics

The wave functions and energy spectrum of electrons in size-quantized n-Ge and n-Si films are obtained and the anisotropy of the electron state density is investigated. Also, the analytical expressions for the electronic part of heat capacity at the various approximations of electron gas degeneration are obtained.

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Doping Effects Of Ga And Te On The Kinetic Coefficients Of Rhombohedral And Cubic Phases Of Ge_{1-X} Ga_X Te Solid Solution Alloys, T. Atalay, M.H. Akperov Jan 1998

Doping Effects Of Ga And Te On The Kinetic Coefficients Of Rhombohedral And Cubic Phases Of Ge_{1-X} Ga_X Te Solid Solution Alloys, T. Atalay, M.H. Akperov

Turkish Journal of Physics

In this study Ga and Te doping effects on the kinetic parameters (thermo e.m.f., electrical conductivity, heat conductivity, Hall and Nernst-Ettingshausen coefficients) of the rhombohedral and cubic phases of Ge_{1-x} Ga_x Te (0 < x \leq 0,06) solid solutions has been investigated between 77-900 K temperature intervals. Increase in the amount of Te increases hole concentration and reduces lattice constant, whereas rhombohedral propeties of GeTe rises with increase of Ga concentration. The observed anomalies on the kinetic parameters may be explained qualitatively by the complexity of the Fermi surface shape and the zone model of GeTe which involves the seperation of the L extremums that is same for ``\alpha'', ``\beta'' and ``\gamma'' phases of the compound.

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Elastic Scattering Of 344.5 Mev ^{12}C Ions From ^{11}B Nucleus, S.A.E. Khallaf, M.A. Abdel-Rahman, S.K. Abdel-Rahman, S.W.Z. Mahmoud Jan 1998

Elastic Scattering Of 344.5 Mev ^{12}C Ions From ^{11}B Nucleus, S.A.E. Khallaf, M.A. Abdel-Rahman, S.K. Abdel-Rahman, S.W.Z. Mahmoud

Turkish Journal of Physics

The angular distribution of the elastic scattering differential cross section of 344.5 MeV $^{12}$C ions from $^{11}$B nucleus is calculated and compared with the experimental data as well as the previously published calculations. The real part of the central optical potential is derived using the double-folding and single-folding procedures assuming Gaussian forms of the nucleon-nucleon and alpha-nucleon interactions, respectively. A nuclear matter density distribution function of $^{11}$B consisting of a spherical part plus a quadrupole term is used. The inclusion of the quadrupole term is found necessary to obtain good fits to the experimental data.

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The Influence Of The Dispersion Of Boron Silicate On The Migration Of Non-Equilibrium Charge Carriers Generated By Eect Of An Electric Discharge, A.M. Hasanov Jan 1998

The Influence Of The Dispersion Of Boron Silicate On The Migration Of Non-Equilibrium Charge Carriers Generated By Eect Of An Electric Discharge, A.M. Hasanov

Turkish Journal of Physics

ESR was used in an investigation of the influence of Boron Silicate dispersion on the accumulation of paramagnetic centers (PC). It was observed that the rate of accumulation of PC increase by increasing of the grain size (r). At $r < 0.08$ mm the electrons ($F^+$-centers) are localized on the surface and with increasing grain size up to $0.08 < r < 0.22$ mm charge stratification takes place, the electrons are distributed in near-surface layer and the holes ($V$-centers) are localized in the bulk of the insulator. It was established that the transport of non-equilibrium charge carriers (NCC) from the bulk to the surface of Boron Silicate was due to a drift from the depth $(d \sim 10 \mu m)$ to a bulk-charge field generated by an electric discharge. The value of the surface field $E_s \sim 10^5 V/cm$ is determined by experimental results of the data. The kinetics of the isothermal annealing (300 K) are used to establish the influence of the surface field on the annihilation of NCC in the ''dead'' layer of separated charges.

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Novel Electronic And Magnetic Properties Of Ultrathin Chromium Oxide Films Grown On Pt(111), P S. Robbert, H Geisler, C A. Ventrice Jr, J Van Ek, S Chaturvedi, J A. Rodriguez, M Kuhn, U Diebold Jan 1998

Novel Electronic And Magnetic Properties Of Ultrathin Chromium Oxide Films Grown On Pt(111), P S. Robbert, H Geisler, C A. Ventrice Jr, J Van Ek, S Chaturvedi, J A. Rodriguez, M Kuhn, U Diebold

Physics Faculty Publications

The growth of epitaxial metal–oxide films on lattice-mismatched metal substrates often results in the formation of unique overlayer structures. In particular, epitaxial chromium oxide films grown on Pt(111) exhibit a p(2×2) symmetry through the first two monolayers of growth which is followed by a (√3×√3)R30° phase that is attributed to the growth of a Cr2O3(0001) overlayer. Ultraviolet photoelectron spectroscopy measurements have been performed on the CrOx/Pt(111) system. The electronic structures of CrO2, Cr2O3, and Cr3O4 were calculated using the linear muffin-tin orbital method in …

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Letter To The Editor, John C. Wheeler Jan 1998

Letter To The Editor, John C. Wheeler

Journal of the Minnesota Academy of Science

No abstract provided.

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Resonans Reflectionless Absorption Ofelectromagnetic Waves In Solutions, E. Salaev, E. Gasimov, S. Azizov, J. Qajar Jan 1998

Resonans Reflectionless Absorption Ofelectromagnetic Waves In Solutions, E. Salaev, E. Gasimov, S. Azizov, J. Qajar

Turkish Journal of Physics

No abstract provided.

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Integrable Unsteady Motion With An Application To Ocean Eddies, A. D. Kirwan Jr., Bruce L. Lipphardt Jan 1998

Integrable Unsteady Motion With An Application To Ocean Eddies, A. D. Kirwan Jr., Bruce L. Lipphardt

CCPO Publications

Application of the Brown-Samelson theorem, which shows that particle motion is integrable in a class of vorticity-conserving, two-dimensional incompressible hows, is extended here to a class of explicit time dependent dynamically balanced flows in multilayered systems. Particle motion for nonsteady two-dimensional flows with discontinuities in the vorticity or potential vorticity fields (modon solutions) is shown to be integrable. An example of a two-layer modon solution constrained by observations of a Gulf Stream ring system is discussed.

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Frequency Modulated Excitation Of A Two-Level Atom, Michael W. Noel, W. M. Griffith, T. F. Gallagher Jan 1998

Frequency Modulated Excitation Of A Two-Level Atom, Michael W. Noel, W. M. Griffith, T. F. Gallagher

Physics Faculty Research and Scholarship

We present a detailed experimental study of the frequency-modulated excitation of a two-level atom, using a microwave field to drive transitions between two Rydberg Stark states of potassium. In the absence of a modulation the interaction is the standard model of the Rabi problem, producing sinusoidal oscillations of the population between the two states. In the presence of a frequency modulation of the interacting field, however, the time evolution of the system is significantly modified, producing square wave oscillations of the popula- tion, sinusoidal oscillations at a different frequency, or even sinusoidal oscillations built up in a series of stair …

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