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Tev Black Hole Fragmentation And Detectability In Extensive Air Showers, Eun-Joo Ahn, Maximo Ave, Marco Cavaglia, Angela V. Olinto Aug 2003

Tev Black Hole Fragmentation And Detectability In Extensive Air Showers, Eun-Joo Ahn, Maximo Ave, Marco Cavaglia, Angela V. Olinto

Physics Faculty Research & Creative Works

In models with large extra dimensions, particle collisions with a center-of-mass energy larger than the fundamental gravitational scale can generate nonperturbative gravitational objects. Since cosmic rays have been observed with energies above 108 TeV, gravitational effects in the TeV energy range can, in principle, be observed by ultrahigh energy cosmic ray detectors. We consider the interaction of ultrahigh energy neutrinos in the atmosphere and compare extensive air showers from TeV black hole formation and fragmentation with standard model processes. Departures from the standard model predictions arise in the interaction cross sections and in the multiplicity of secondary particles. Large …

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Effect Of Kerr Nonlinearity On Defect Lasing Modes In Weakly Disordered Photonic Crystals, Boyang Liu, Alexey Yamilov, Hui Cao Aug 2003

Effect Of Kerr Nonlinearity On Defect Lasing Modes In Weakly Disordered Photonic Crystals, Boyang Liu, Alexey Yamilov, Hui Cao

Physics Faculty Research & Creative Works

We studied the effect of Kerr nonlinearity on lasing in defect modes of weakly disordered photonic crystals. Our time-independent calculation based on self-consistent nonlinear transfer matrix method shows that Kerr nonlinearity modifies both frequencies and quality factors of defect modes. We also used a time-dependent algorithm to investigate the dynamic nonlinear effect. Under continuous pumping, the spatial sizes and intensities of defect lasing modes are changed by Kerr nonlinearity. Such changes are sensitive to the nonlinear response time.

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Static And Dynamic Dipole Polarizability Of The Helium Atom Using Wave Functions Involving Logarithmic Terms, Mauro Masili, Anthony F. Starace Jul 2003

Static And Dynamic Dipole Polarizability Of The Helium Atom Using Wave Functions Involving Logarithmic Terms, Mauro Masili, Anthony F. Starace

Department of Physics and Astronomy: Faculty Publications

We present a calculation of the static and dynamic dipole polarizability of the helium atom using a variationally stable treatment that incorporates the coupled-channel hyperspherical representation of the wave functions. Inclusion of logarithmic terms in intermediate functions as well as the effect of an optimization procedure for the variational parameter are analyzed. When available, our coupled-channel results are compared with other values in the literature.

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The Structures Of Fluorene– (H2o)1,2 Determined By Rotational Coherence Spectroscopy, David M. Laman, Alan G. Joly, Douglas Ray Jul 2003

The Structures Of Fluorene– (H2o)1,2 Determined By Rotational Coherence Spectroscopy, David M. Laman, Alan G. Joly, Douglas Ray

All Faculty Scholarship for the College of the Sciences

Rotational coherence spectroscopy ~RCS!, via time-correlated single photon counting, and two-color resonant two-photon ionization ~R2PI! time-of-flight mass spectrometry, have been used to characterize fluorene–(water)1,2[FL– (H2O)1,2] van der Waals clusters generated in supersonic jets. Rotational coherence traces have been obtained at excitation energies corresponding to several resonant features in the S1<-S0 R2PI spectra of FL– (H2O)1,2 . RCS simulations and diagonalization of the moment of inertia tensor have been used to obtain S1 excited state rotational constants and structures of FL– (H2O)1,2 that are consistent with …

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Multienergetic External-Beam Pixe As A Means Of Stydying The Surface Enrichment Effect In Coins, Scott Evans Perry Jul 2003

Multienergetic External-Beam Pixe As A Means Of Stydying The Surface Enrichment Effect In Coins, Scott Evans Perry

Theses and Dissertations

This thesis paper examines the feasibility of using external-beam PIXE to study the surface enrichment effect in metal artifacts. By varying the energy of the incident proton beam, we penetrated the artifact's surface to different levels and were able to produce a depth profile of the elemental composition of the sample. In this study, the sample set we chose to examine consisted of ancient and modern coins. This paper first describes the surface enrichment effect and theoretically how PIXE can be used to study it. It then details the construction of the components of the external-beam setup. Many of the …

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Central Pseudorapidity Gaps In Events With A Leading Antiproton At The Fermilab Tevatron P̅P Collider, Darin Acosta, Kenneth A. Bloom, Collider Detector At Fermilab Collaboration Jul 2003

Central Pseudorapidity Gaps In Events With A Leading Antiproton At The Fermilab Tevatron P̅P Collider, Darin Acosta, Kenneth A. Bloom, Collider Detector At Fermilab Collaboration

Kenneth Bloom Publications

We report a measurement of the fraction of events with a large pseudorapidity gap Δη within the pseudorapidity region available to the proton dissociation products X in p̅+p→p̅+X. For a final state p̅of fractional momentum loss ξp̅ and 4-momentum transfer squared tp̅ within 0.06<ξp̅tp̅|2 at √s=1800 [630] GeV, the fraction of events with Δη>3 is found to be 0.246±0.001 (stat)±0.042 (syst) [0.184±0.001 (stat)±0.043 (syst)]. Our results are compared with gap fractions measured in minimum bias p̅p collisions and with theoretical expectations.

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So(2,1) Conformal Anomaly: Beyond Contact Interactions, Horacio E. Camblong Jul 2003

So(2,1) Conformal Anomaly: Beyond Contact Interactions, Horacio E. Camblong

Physics and Astronomy

The existence of anomalous symmetry-breaking solutions of the SO(2,1) commutator algebra is explicitly extended beyond the case of scale-invariant contact interactions. In particular, the failure of the conservation laws of the dilation and special conformal charges is displayed for the two-dimensional inverse square potential. As a consequence, this anomaly appears to be a generic feature of conformal quantum mechanics and not merely an artifact of contact interactions. Moreover, a renormalization procedure traces the emergence of this conformal anomaly to the ultraviolet sector of the theory, within which lies the apparent singularity.

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Experimental And Calculated Stark Widths Within The Kr I Spectrum, Vladimir Milosavljevic, Stevan Djenize, Milan S. Dimitrijevic Jul 2003

Experimental And Calculated Stark Widths Within The Kr I Spectrum, Vladimir Milosavljevic, Stevan Djenize, Milan S. Dimitrijevic

Articles

On the basis of the precisely recorded 20 neutral krypton (Kr I) line shapes (in the 5s−5p and 5s−6p transitions), we have obtained the basic plasma parameters, i.e., electron temperature (T) and electron density (N) using our line deconvolution procedure in a plasma created in a linear, low-pressure, pulsed arc discharge operated in krypton. The mentioned plasma parameters have also been measured using independent experimental diagnostics techniques. Agreement has been found among the two sets of the obtained parameters. This recommends our deconvolution procedure for plasma diagnostical purposes, especially in astrophysics where direct measurements of the …

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Validation Of Imaging Doppler Interferometer Winds Using Meteor Radar, G. O.L. Jones, C. S. Fish, W. K. Hocking, Michael J. Taylor Jul 2003

Validation Of Imaging Doppler Interferometer Winds Using Meteor Radar, G. O.L. Jones, C. S. Fish, W. K. Hocking, Michael J. Taylor

All Physics Faculty Publications

There has been some debate over the years concerning the accuracy of mesospheric wind observations made using the imaging Doppler interferometer (IDI) technique. The high potential and increasing use of IDI wind data in joint studies with spaced-antenna MF and meteor radar systems make it important to quantify the IDI results. This paper presents a novel comparison of wind measurements between a dynasonde implementation of IDI and winds derived from an all-sky meteor radar system, a widely-accepted standard for such measurements. Both radars were located at the USU Bear Lake Observatory and operated almost continuously for a four-month period. The …

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Frequency Scanned Interferometer Demonstration System, Tim Blass, Jason A. Deibel, Sven Nyberg, Keith Riles, Haijun Yang Jul 2003

Frequency Scanned Interferometer Demonstration System, Tim Blass, Jason A. Deibel, Sven Nyberg, Keith Riles, Haijun Yang

Physics Faculty Publications

No abstract provided.

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Nucleon-Nucleon Spin Dependent Scattering Amplitudes To Describe Final State Interactions In Electromagnetic And Electroweak Nuclear Processes, William P. Ford Jul 2003

Nucleon-Nucleon Spin Dependent Scattering Amplitudes To Describe Final State Interactions In Electromagnetic And Electroweak Nuclear Processes, William P. Ford

Physics Theses & Dissertations

There are currently no models readily available that provide nucleon-nucleon spin dependent scattering amplitudes at high energies ( s ≥ 6 GeV2). This work aims to provide a model for calculating these high-energy scattering amplitudes. The foundation of the model is Regge theory since it allows for a relativistic description and full spin dependence. A parameterization of the amplitudes is presented. and comparisons of the solution to the assembled data set are shown. In addition, an application of the model to describe final state interactions in deuteron electrodisintegration is presented. Overall the model works as intended, and provides …

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Extrapolation Of The Zα-Expansion And Two-Loop Bound-State Energy Shifts, Ulrich D. Jentschura Jul 2003

Extrapolation Of The Zα-Expansion And Two-Loop Bound-State Energy Shifts, Ulrich D. Jentschura

Physics Faculty Research & Creative Works

Quantum electrodynamic (QED) effects that shift the binding energies of hydrogenic energy levels have been expressed in terms of a semi-analytic expansion in powers of Zα and ln[(Zα)-2], where Z is the nuclear charge number and α is the fine-structure constant. For many QED effects, numerical data are available in the domain of high Z where the Zα expansion fails. In this Letter, we demonstrate that it is possible, within certain limits of accuracy, to extrapolate the Zα-expansion from the low-Z to the high-Z domain. We also review two-loop self-energy effects and provide an estimate for the problematic …

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Charge Transfer In Slow Collisions Of H⁺ With Na, Anh-Thu Le, Chen-Nan Liu, C. D. Lin Jul 2003

Charge Transfer In Slow Collisions Of H⁺ With Na, Anh-Thu Le, Chen-Nan Liu, C. D. Lin

Physics Faculty Research & Creative Works

We reexamined charge-transfer cross sections for protons colliding with Na(3s) atoms for collision energies from the threshold at 1.7 eV to 40 eV using the recently developed hyperspherical close-coupling method. Our results disagree with the recent calculations by Dutta et al. [Phys. Rev. A 63, 022709 (2001)], but are in good agreement with the earlier calculations of Croft and Dickinson [J. Phys. B 29, 57 (1996)] except at energies below 3 eV. Our calculations support the doubt on the experimental data of Kushawaha.

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Comment On: 'Depolarization Corrections To The Coercive Field In Thin-Film Ferroelectrics', Stephen Ducharme, Vladimir Fridkin Jul 2003

Comment On: 'Depolarization Corrections To The Coercive Field In Thin-Film Ferroelectrics', Stephen Ducharme, Vladimir Fridkin

Stephen Ducharme Publications

The Letter by Dawber et al. [J. Phys.: Condens. Matter 15 L393 (2003)] notes that incomplete screening in the electrodes of a ferroelectric capacitor can result in an underestimate for the true coercive field in films of nanometer thickness. We show that their estimate of the magnitude of this correction it too large in the case of ferroelectric copolymer Langmuir- Blodgett films and, as a result, invalidates the claim that finite-size scaling of the ferroelectric coercive field is evident in films thinner than 15 nm.

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Search For Large Extra Dimensions In The Monojet +ET Channel With The Dø Detector, V. M. Abazov, Gregory R. Snow, D0 Collaboration Jun 2003

Search For Large Extra Dimensions In The Monojet +ET Channel With The Dø Detector, V. M. Abazov, Gregory R. Snow, D0 Collaboration

Gregory Snow Publications

We present a search for large extra dimensions (ED) in pp̅ collisions at a center-of-mass energy of 1.8 TeV using data collected by the DØ detector at the Fermilab Tevatron in 1994–1996. Data corresponding to 78.8 ± 3.9 pb-1 are examined for events with large missing transverse energy, one high-pT jet, and no isolated muons. There is no excess observed beyond expectation from the standard model, and we place lower limits on the fundamental Planck scale of 1.0 and 0.6 TeV for 2 and 7 ED, respectively.

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Iteration Methods For Approximating The Lowest Order Energy Eigenstate Of A Given Symmetry For One- And Two-Dimensional Systems, Chad Everett Junkermeier Jun 2003

Iteration Methods For Approximating The Lowest Order Energy Eigenstate Of A Given Symmetry For One- And Two-Dimensional Systems, Chad Everett Junkermeier

Theses and Dissertations

Using the idea that a quantum mechanical system drops to its ground state as its temperature goes to absolute zero several operators are devised to enable the approximation of the lowest order energy eigenstate of a given symmetry; as well as an approximation to the energy eigenvalue of the same order.

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Inelastic Neutron Scattering Signal From Deconfined Spinons In A Fractionalized Antiferromagnet, Courtney Lannert, Matthew P.A. Fisher Jun 2003

Inelastic Neutron Scattering Signal From Deconfined Spinons In A Fractionalized Antiferromagnet, Courtney Lannert, Matthew P.A. Fisher

Physics: Faculty Publications

We calculate the contribution of deconfined spinons to inelastic neutron scattering (INS) in the fractionalized antiferromagnet (AF*), introduced elsewhere. We find that the presence of free spin-1/2 charge-less excitations leads to a continuum INS signal above the Néel gap. This signal is found above and in addition to the usual spin-1 magnon signal, which to lowest order is the same as in the more conventional confined antiferromagnet. We calculate the relative weights of these two signals and find that the spinons contribute to the longitudinal response, where the magnon signal is absent to lowest order. Possible higher-order effects of interactions …

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Radio Polarization Of The Young High-Magnetic-Field Pulsar Psr J1119-6127, Fronefield Crawford, Nathan C. Keim Jun 2003

Radio Polarization Of The Young High-Magnetic-Field Pulsar Psr J1119-6127, Fronefield Crawford, Nathan C. Keim

Physics

We have investigated the radio polarization properties of PSR J1119-6127, a recently discovered young radio pulsar with a large magnetic field. Using pulsar-gated radio imaging data taken at a center frequency of 2496 MHz with the Australia Telescope Compact Array, we have determined a rotation measure for the pulsar of +842 +/- 23 rad m^-2. These data, combined with archival polarimetry data taken at a center frequency of 1366 MHz with the Parkes telescope, were used to determine the polarization characteristics of PSR J1119-6127 at both frequencies. The pulsar has a fractional linear polarization of ~75% and ~55% at 1366 …

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Phase Ii: Design And Analysis Of A Process For Melt Casting Metallic Fuel Pins Incorporating Volatile Actinides, Yitung Chen, Randy Clarksean, Darrell Pepper Jun 2003

Phase Ii: Design And Analysis Of A Process For Melt Casting Metallic Fuel Pins Incorporating Volatile Actinides, Yitung Chen, Randy Clarksean, Darrell Pepper

Fuels Campaign (TRP)

This research report develops a model to analyze the transport of americium from the melt to the vapor phase above the crucible. The model considers mass transport in the melt, vaporization at the surface, and transport through the vapor phase. The greatest problem with the model is the uncertainty of the thermodynamic properties of the proposed ternary alloy. The details of the model and the specific quantities needed for the physical properties will be discussed.

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Theoretical Study On The Optical Properties Of Polyvinylidene Fluoride Crystal, Chun-Gang Duan, Wai-Ning Mei, Wei-Guo Yin, Jianjun Liu, J. R. Hardy, Mengjun Bai, Stephen Ducharme Jun 2003

Theoretical Study On The Optical Properties Of Polyvinylidene Fluoride Crystal, Chun-Gang Duan, Wai-Ning Mei, Wei-Guo Yin, Jianjun Liu, J. R. Hardy, Mengjun Bai, Stephen Ducharme

Stephen Ducharme Publications

We report our first-principles studies on the linear and non-linear optical properties of ferroelectric polyvinylidene fluoride crystal. Calculated values of the refractive indices agree well with experiments. As regards the second-harmonic-generation coefficients, theoretical values are larger than experimental ones. Possible reasons for the discrepancy are discussed.

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The Flaring H2o Megamaser And Compact Radio Source In Markarian 348, A. B. Peck, C. Henkel, J. S. Ulvestad, A. Brunthaler, H. Falcke, Moshe Elitzur, K. M. Menten, J. F. Gallimore Jun 2003

The Flaring H2o Megamaser And Compact Radio Source In Markarian 348, A. B. Peck, C. Henkel, J. S. Ulvestad, A. Brunthaler, H. Falcke, Moshe Elitzur, K. M. Menten, J. F. Gallimore

Physics and Astronomy Faculty Publications

We report on single-dish monitoring and extremely high angular resolution observations of the flaring H2O megamaser in the Seyfert 2 galaxy Mrk 348. The H2O line is redshifted by ~130 km s-1 with respect to the systemic velocity, is very broad, with an FWHM of 130 km s-1, and has no detectable high-velocity components within 1500 km s-1 on either side of the strong line. Monitoring observations made with the Effelsberg 100 m telescope show that the maser varies significantly on timescales as short as 1 day and that the integrated line …

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Radiative Decays Involving A0(980) And F0(980) In The Vector Meson Dominance Model, Joseph Schechter, Deirdre Black, Masayasu Harada Jun 2003

Radiative Decays Involving A0(980) And F0(980) In The Vector Meson Dominance Model, Joseph Schechter, Deirdre Black, Masayasu Harada

Physics - All Scholarship

We summarize some features of the vector meson dominance model which was recently proposed for studying radiative decays involving the scalar mesons. Using the experimental values of \Gamma(a_0 \to \gamma\gamma), \Gamma(f_0 \to \gamma\gamma) and \Gamma(\phi \to a_0 \gamma) as inputs, we show that the model predicts a large hierarchy between \Gamma(a_0 \to \omega \gamma) and \Gamma(a_0 \to \rho \gamma) as well as between \Gamma(f_0 \to \omega \gamma) and \Gamma(f_0 \to \rho \gamma).

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Search For Associated Production Of Υand Vector Boson In Pp̅ Collisions At √S =1.8 Tev, Darin Acosta, Kenneth A. Bloom, Collider Detector At Fermilab Collaboration Jun 2003

Search For Associated Production Of Υand Vector Boson In Pp̅ Collisions At √S =1.8 Tev, Darin Acosta, Kenneth A. Bloom, Collider Detector At Fermilab Collaboration

Kenneth Bloom Publications

We present a search for associated production of the Υ (1S) and a vector boson in 83 pb-1 of pp̅ collisions at √s =1.8 TeV collected by the CDF experiment in 1994–1995. We find no evidence of the searched signal in the data, and set upper limits to the production cross sections.

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Observations Of Discrete, Global Magnetospheric Oscillations Directly Driven By Solar Wind Density Variations, L. Kepko, Harlan E. Spence Jun 2003

Observations Of Discrete, Global Magnetospheric Oscillations Directly Driven By Solar Wind Density Variations, L. Kepko, Harlan E. Spence

Physics & Astronomy

No abstract provided.

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Comparative Study Of Embedding Methods, C. J. Cellucci, Alfonso M. Albano, P. E. Rapp Jun 2003

Comparative Study Of Embedding Methods, C. J. Cellucci, Alfonso M. Albano, P. E. Rapp

Physics Faculty Research and Scholarship

Embedding experimental data is a common first step in many forms of dynamical analysis. The choice of appropriate embedding parameters (dimension and lag) is crucial to the success of the subsequent analysis. We argue here that the optimal embedding of a time series cannot be determined by criteria based solely on the time series itself. Therefore we base our analysis on an examination of systems that have explicit analytic representations. A comparison of analytically obtained results with those obtained by an examination of the corresponding time series provides a means of assessing the comparative success of different embedding criteria. The …

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Measuring Boltzmann's Constant Using Video Microscopy Of Brownian Motion, Paul Nakroshis, Matthew Amoroso, Jason Legere, Christian Smith Jun 2003

Measuring Boltzmann's Constant Using Video Microscopy Of Brownian Motion, Paul Nakroshis, Matthew Amoroso, Jason Legere, Christian Smith

USM Physics Program

Boltzmann's constant k was measured by observing the Brownian motion of polystyrene spheres in water. An inexpensive monochrome CCD camera and video card were used to create a video of the spheres' motion. After preprocessing the images, custom routines were used to examine the video and to identify and track the particles from one frame to the next. From the mean squared displacement of the particles versus time, we extracted the value of k from the slope, assuming that the drag force on an individual sphere is well modeled by Stokes' law.

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Thickness Dependence Of Magnetic Blocking In Granular Thin Films With Interacting Magnetic Particles, Jian Qing Wang, Zhi Dong Zhao, Scott L. Whittenburg Jun 2003

Thickness Dependence Of Magnetic Blocking In Granular Thin Films With Interacting Magnetic Particles, Jian Qing Wang, Zhi Dong Zhao, Scott L. Whittenburg

Chemistry and Biochemistry Faculty Publications

Interparticle interaction among single domain nanosize magnetic particles embedded in nonmagnetic matrix was studied. Attention was paid to concentrated Cu–Co granular thin films with a fixed magnetic volume fraction (20%). By analyzing theoretical models and comparing with experimental results, a dimensional constraint on the magnetic properties was found. As the film thickness reduces toward the thin limit the interparticle interaction plays important roles in modifying the magnetic behavior. The dipolar interaction energy was calculated among magnetic particles including far-neighbor interaction for films with different thickness values. When magnetization variation is included in the calculation, the resulting calculated interaction energy versus …

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Use Of Optical Tweezers For Colloid Science, Andrew Resnick Jun 2003

Use Of Optical Tweezers For Colloid Science, Andrew Resnick

Physics Faculty Publications

A space-borne optical tweezer apparatus for use with colloidal crystallization experiments has been characterized. The trapping force has been measured as a function of index mismatch between colloidal microspheres and the surrounding fluid and as a function of particle size. This work also presents a method to determine the refractive index of a colloidal microsphere, which is then used to calculate the applied trapping force for the case of an arbitrary background fluid. This is useful for work with dense colloidal suspensions when the usual (e.g., Stokes flow) trap force measurement methods do not apply, as well as microrheological studies …

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Effect Of H-2 On The Martian Ionosphere: Implications For Atmospheric Evolution, Jane L. Fox Jun 2003

Effect Of H-2 On The Martian Ionosphere: Implications For Atmospheric Evolution, Jane L. Fox

Physics Faculty Publications

Because H2 reacts efficiently with O+, CO2 +, CO+, and N2 +, the molecular hydrogen abundance assumed in models of the Martian ionosphere greatly affects the high altitude density profiles of these ions. We have found that models of the low solar activity Martian ionosphere exhibit much smaller O+ densities than the measured values if the adopted H2 abundance is of the order of 40 ppm, the value proposed in a 1998 model of the Martian atmosphere. For a model based on the recently measured H2 abundance of …

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High Pressure Effects On Electron Transport And Structure Of Colossal Magnetoresistive Materials, Congwu Cui May 2003

High Pressure Effects On Electron Transport And Structure Of Colossal Magnetoresistive Materials, Congwu Cui

Dissertations

Pressure effects on the electronic, magnetic properties and structure of several typical colossal magnetoresistive manganites, La0.60Y0.07Ca0.33MnO3, Pr1-xCaxMn03 (X = 0.25, 0.30, 0.35), Nd1-xSrxMnO3 (x = 0.45, 0.50), were explored through high pressure resistivity and structure measurements. It was shown that pressure up to ~7 GPa induces more complicated charge, spin and lattice state changes than in the low pressure range explored previously. In La0.60Y0.07Ca0.33MnO3, pressure induces a local atomic structure transformation at a critical …

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