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Articles 29041 - 29070 of 36693

Full-Text Articles in Physical Sciences and Mathematics

Cooling Atoms In An Optical Trap By Selective Parametric Excitation, Nicola Poli, Robert J. Brecha, Giacomo Roati, Giovanni Modugno Jan 2002

Cooling Atoms In An Optical Trap By Selective Parametric Excitation, Nicola Poli, Robert J. Brecha, Giacomo Roati, Giovanni Modugno

Physics Faculty Publications

We demonstrate the possibility of energy-selective removal of cold atoms from a tight optical trap by means of parametric excitation of the trap vibrational modes. Taking advantage of the anharmonicity of the trap potential, we either selectively remove the most energetic trapped atoms or excite those at the bottom of the trap by tuning the parametric modulation frequency. This process, which had been previously identified as a possible source of heating, also appears to be a robust way for forcing evaporative cooling in anharmonic traps.

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A 0.5 Μm Thick Polysilicon Schottky Diode With Rectification Ratio Of 10^6, Elena A. Guliants, Chunhai Ji, Young J. Song, Wayne A. Anderson Jan 2002

A 0.5 Μm Thick Polysilicon Schottky Diode With Rectification Ratio Of 10^6, Elena A. Guliants, Chunhai Ji, Young J. Song, Wayne A. Anderson

Electrical and Computer Engineering Faculty Publications

Polycrystalline Si films, 0.5-mm thick, were obtained as a result of metal-induced growth by sputtering from a Si target on 25 nm thick Ni prelayers at 525 °C. Silicon grew heteroepitaxially on the NiSi2 layer formed due to the reaction between the sputtered Si atoms and Ni. Schottky diodes were fabricated on the Si films by deposition of a Schottky metal on the front surface of the film while Ni disilicide provided an intimate ohmic contact at the back. A Pd/n-Si diode using an n-Si film annealed for 2 h at 700 °C in forming gas demonstrated a rectification ratio …

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Implementation Of A Si/Sic Hybrid Optically Controlled High-Power Switching Device, Prashant Bhadri, Kuntao Ye, Elena A. Guliants, Fred R. Beyette Jr. Jan 2002

Implementation Of A Si/Sic Hybrid Optically Controlled High-Power Switching Device, Prashant Bhadri, Kuntao Ye, Elena A. Guliants, Fred R. Beyette Jr.

Electrical and Computer Engineering Faculty Publications

The ever-increasing performance and economy of operation requirements placed on commercial and military transport aircraft are resulting in very complex systems. As a result, the use of fiber optic component technology has lead to high data throughput, immunity to EMI, reduced certification and maintenance costs and reduced weight features. In particular, in avionic systems, data integrity and high data rates are necessary for stable flight control. Fly-by-Light systems that use optical signals to actuate the flight control surfaces of an aircraft have been suggested as a solution to the EMI problem in avionic systems. Current fly-by-light systems are limited by …

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Angular Range For Reflection Of P-Polarized Light At The Surface Of An Absorbing Medium With Reflectance Below That At Normal Incidence, R. M.A. Azzam, Ericson E. Ugbo Jan 2002

Angular Range For Reflection Of P-Polarized Light At The Surface Of An Absorbing Medium With Reflectance Below That At Normal Incidence, R. M.A. Azzam, Ericson E. Ugbo

Electrical Engineering Faculty Publications

The range of incidence angle, 0 < φ < φe, over which p-polarized light is reflected at interfaces between transparent and absorbing media with reflectance below that at normal incidence is determined. Contours of constant φe in the complex plane of the relative dielectric constant ε are presented. A method for determining the real and imaginary parts of the complex refractive index, ε1/2 = n + jk, which is based on measuring φe and the pseudo-Brewster angle φpB, is viable in the domain of fractional optical constants, n, k < 1.

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Donor And Acceptor Concentrations In Degenerate Inn, David C. Look, H. Lu, William J. Schaff, J. Jasinski, Z. Liliental-Weber Jan 2002

Donor And Acceptor Concentrations In Degenerate Inn, David C. Look, H. Lu, William J. Schaff, J. Jasinski, Z. Liliental-Weber

Physics Faculty Publications

A formalism is presented to determine donor (ND) and acceptor (NA) concentrations in wurtzitic InN characterized by degenerate carrier concentration (n) and mobility (μ). The theory includes scattering not only by charged point defects and impurities, but also by charged threading dislocations, of concentration Ndis. For a 0.45-μm-thick InN layer grown on Al2O3 by molecular beam epitaxy, having Ndis = 5×1010 cm−2, determined by transmission electron microscopy, n(20 K) = 3.5×1018 cm−3 and μ(20 K) = 1055 cm2 …

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Cosmology With Negative Potentials, Gary Felder, Andrei Frolov, Lev Kofman, Andrei Linde Jan 2002

Cosmology With Negative Potentials, Gary Felder, Andrei Frolov, Lev Kofman, Andrei Linde

Physics: Faculty Publications

We investigate cosmological evolution in models where the effective potential V(f) may become negative for some values of the field f. Phase portraits of such theories in the space of variables (f,f˙ ,H) have several qualitatively new features as compared with phase portraits in the theories with V(f).0. Cosmological evolution in models with potentials with a ‘‘stable’’ minimum at V(f),0 is similar in some respects to the evolution in models with potentials unbounded from below. Instead of reaching an AdS regime dominated by the negative vacuum energy, the universe reaches a turning point where its energy density vanishes, and then …

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Cooper Pair Islanding Model Of Insulating Nanohoneycomb Films, Shawna M. Hollen, J M. Valles Jr. Jan 2002

Cooper Pair Islanding Model Of Insulating Nanohoneycomb Films, Shawna M. Hollen, J M. Valles Jr.

Physics & Astronomy

We first review evidence for the Cooper pair insulator (CPI) phase in amorphous nanohoneycomb (NHC) films. We then extend our analysis of superconducting islands induced by film thickness variations in NHC films to examine the evolution of island sizes through the magnetic field-driven SIT. Finally, using the islanding picture, we present a plausible model for the appearance and behavior of the CPI phase in amorphous NHC films.

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High Spatial Resolution Thermal Conductivity Of Bulk Zno (0001), Diana I. Florescu, L. G. Mourokh, Fred H. Pollak, David C. Look, G. Cantwell, X. Li Jan 2002

High Spatial Resolution Thermal Conductivity Of Bulk Zno (0001), Diana I. Florescu, L. G. Mourokh, Fred H. Pollak, David C. Look, G. Cantwell, X. Li

Physics Faculty Publications

We measured high spatial/depth resolution 300 K thermal conductivity κ of the Zn and O surfaces of two bulk n-type ZnO (0001) samples, grown by a vapor-phase transport method, using scanning thermal microscopy (SThM). The thermal investigation was performed in both point-by-point (∼2 μm resolution) and area-scan modes. On the first sample κ=1.16±0.08 (Zn face)/1.10±0.09 (O face) W/cm K while for the second material κ=1.02±0.07 (Zn face)/0.98±0.08 (O face) W/cm K. These are the highest κ values reported on ZnO. A correlation between SThM area-scan readings and surface topography was established by simultaneously performing atomic force microscopy scans. The …

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Coherent Integration Of 0.5 Ghz Spectral Holograms At 1536 Nm Using Dynamic Biphase Codes, Z Cole, Thomas Böttger, R Krishna Mohan, R Reibel, W R. Babbitt, R L. Cone, K D. Merkel Jan 2002

Coherent Integration Of 0.5 Ghz Spectral Holograms At 1536 Nm Using Dynamic Biphase Codes, Z Cole, Thomas Böttger, R Krishna Mohan, R Reibel, W R. Babbitt, R L. Cone, K D. Merkel

Physics and Astronomy

Spectral hole-burning-based optical processing devices are proposed for coherent integration of multiple high-bandwidth interference patterns in a spectral hole-burning medium. In this implementation, 0.5 GHz spectral holographic gratings are dynamically accumulated in Er3+:Y2SiO5" style="position: relative;" tabindex="0" id="MathJax-Element-1-Frame">Er3+:Y2SiO5 at 4.2 K using a 1536 nm laser frequency stabilized to a spectral hole, along with commercial off-the-shelf components. The processed data, representing time delays over 0.5–2.0 μs, were optically read out using a frequency-swept probe; this approach makes possible the use of low-bandwidth, large-dynamic-range detectors and digitizers and enables competitive processing for applications such as radar,lidar, and radio astronomy. Coherent integration …

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Mutual Constraints Between Reionization Models And Parameter Extraction From Cosmic Microwave Background Data, Aparna Venkatesan Jan 2002

Mutual Constraints Between Reionization Models And Parameter Extraction From Cosmic Microwave Background Data, Aparna Venkatesan

Physics and Astronomy

Spectroscopic studies of high-redshift objects and increasingly precise data on the cosmic microwave background (CMB) are beginning to independently place strong complementary bounds on the epoch of hydrogen reionization. Parameter estimation from current CMB data continues, however, to be subject to several degeneracies. Here, we focus on those degeneracies in CMB parameter forecasts related to the optical depth to reionization. We extend earlier work on the mutual constraints that such analyses of CMB data and a reionization model may place on each other to a more general parameter set and to the case of data anticipated from the MAP satellite. …

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Modeling An Electrosensory Landscape: Behavioral And Morphological Optimization In Elasmobranch Prey Capture, Brandon R. Brown Jan 2002

Modeling An Electrosensory Landscape: Behavioral And Morphological Optimization In Elasmobranch Prey Capture, Brandon R. Brown

Physics and Astronomy

Most biological sensory systems benefit from multiple sensors. Elasmobranchs (sharks, skates and rays) possess an array of electroreceptive organs that facilitate prey location, mate location and navigation. Here, the perceived electrosensory landscape for an elasmobranch approaching prey is mathematically modeled. The voltages that develop simultaneously in dozens of separate sensing organs are calculated using electrodynamics. These voltages lead directly to firing rate modifications in the primary afferent nerves. The canals connecting the sense organs to an elasmobranch's surface exhibit great variation of location and orientation. Here, the voltages arising in the sense organs are found to depend strongly on the …

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Jecp/Ed Manual, Xingzhong Li Jan 2002

Jecp/Ed Manual, Xingzhong Li

Nebraska Center for Materials and Nanoscience: Faculty Publications

JECP/ED is a Java program with graphic interface for simulating electron diffraction pattern. It is designed and written by Dr. Xingzhong in University of Nebraska- Lincoln. This is verision 12-2002. It can be used for simulating electron diffraction zone pattern(ZOLZ with/without FOLZ), it allows to select zone axis, high voltage, sample thickness in the simulation, optional to show index, intensity and Laue center, featureed with manuniplating the pattern with slightly tilting, 360 degree rotation, zoom. The diffraction intensity is calculated on the basis of the kinematical theory. The program is extended to simulate electron diffraction with a precession of incident …

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Translation Of 'Balika Badhu: A Selected Anthology Of Bengali Short Stories', Monish Ranjan Chatterjee Jan 2002

Translation Of 'Balika Badhu: A Selected Anthology Of Bengali Short Stories', Monish Ranjan Chatterjee

Electrical and Computer Engineering Faculty Publications

This project, which began with the desire to render into English a rather long tale by Bimal Kar about five years ago, eventually grew into a considerably more extended compilation of Bengali short stories by 10 of the most well-known practitioners of that art since the heyday of Rabindranath Tagore. The collection is limited in many ways, not the least of which being that no woman writer has been included, and that it contains only a baker's dozen stories (if we count Bonophool's micro-stories collectively as one ) — a number pitifully small considering the vast and prolific field of …

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First Measurement Of The Double Spin Asymmetry In →E→P → E ‘Π⁺ In The Resonance Region, G. E. Dodge, K. V. Dharmawardane, T. A. Forest, C. E. Hyde-Wright, A. Klein, S. E. Kuhn, R. A. Niyazov, L. B. Weinstein, J. Yun, Et. Al., Clas Collaboration Jan 2002

First Measurement Of The Double Spin Asymmetry In →E→P → E ‘Π⁺ In The Resonance Region, G. E. Dodge, K. V. Dharmawardane, T. A. Forest, C. E. Hyde-Wright, A. Klein, S. E. Kuhn, R. A. Niyazov, L. B. Weinstein, J. Yun, Et. Al., Clas Collaboration

Physics Faculty Publications

The double spin asymmetry in the →e→p → e' π+n reaction has been measured for the first time in the resonance region for four-momentum transfer Q2 = 0.35-1.5 GeV2. Data were taken at Jefferson Lab with the CLAS detector using a 2.6 GeV polarized electron beam incident on a polarized solid NH3 target. Comparison with predictions of phenomenological models shows strong sensitivity to resonance contributions. Helicity-1/2 transitions are found to be dominant in the second and third resonance regions. The measured asymmetry is consistent with a faster rise with Q2 …

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Comment On ‘‘Stress-Density Ratio Slip-Corrected Reynolds Equation For Ultra-Thin Film Gas Bearing Lubrication’’, Alejandro Garcia Jan 2002

Comment On ‘‘Stress-Density Ratio Slip-Corrected Reynolds Equation For Ultra-Thin Film Gas Bearing Lubrication’’, Alejandro Garcia

Alejandro Garcia

No abstract provided.

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Unifying Lectures, Recitations & Laboratories As A Part Of The Humanized Physics Project, Vicki L. Plano Clark, Robert G. Fuller Jan 2002

Unifying Lectures, Recitations & Laboratories As A Part Of The Humanized Physics Project, Vicki L. Plano Clark, Robert G. Fuller

Robert G. Fuller Publications

As a part of our work in the Humanized Physics Project, we have made the content of the physics laboratories the keystone of our physics content coverage. After having selected an appropriate human application of physics for the laboratory each week, we have shaped the lecture, recitation and homework assignments to support the laboratory. Our poster will provide examples from both semesters of our general physics course.

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The B --> S G G Decay In The General Two Higgs Doublet Model, E. O. İltan Jan 2002

The B --> S G G Decay In The General Two Higgs Doublet Model, E. O. İltan

Turkish Journal of Physics

We study the decay width of the inclusive process b --> s g g in the two Higgs doublet model with three-level flavor changing neutral currents (model III). We analyse the dependencies of the differential decay width to the s- quark energy E_s and model III parameters, charged Higgs mass m_H_{^{±}} and Yukawa coupling \bar{\xi}_{N,bb}^D. We observe that there exist a considerable enhancement in the decay width for the relevant process. This enhancement can be reduced by choosing C_7^{eff} as negative or increasing the lower bound of m_H_{^{±}} to the large values. This is an interesting result which gives an …

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Comment On ‘‘Stress-Density Ratio Slip-Corrected Reynolds Equation For Ultra-Thin Film Gas Bearing Lubrication’’, Alejandro Garcia Jan 2002

Comment On ‘‘Stress-Density Ratio Slip-Corrected Reynolds Equation For Ultra-Thin Film Gas Bearing Lubrication’’, Alejandro Garcia

Faculty Publications

No abstract provided.

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Effect Of Oxygen Vacancies On The Magnetic Structure Of The La₀.₆Sr₀.₄Feo3-Δ Perovskite: A Neutron Diffraction Study, Zili Chu, William B. Yelon, Jinbo Yang, William Joseph James, Harlan U. Anderson, Yixiang Xie, Satish K. Malik Jan 2002

Effect Of Oxygen Vacancies On The Magnetic Structure Of The La₀.₆Sr₀.₄Feo3-Δ Perovskite: A Neutron Diffraction Study, Zili Chu, William B. Yelon, Jinbo Yang, William Joseph James, Harlan U. Anderson, Yixiang Xie, Satish K. Malik

Physics Faculty Research & Creative Works

Magnetic interactions in perovskite compounds of the type La1-xSrxMO3-δ (M=3d transition such as Mn and Fe) are presumed to arise through a super exchange between 3d electrons of the magnetic ions via oxygen orbitals. The magnetic structure of La0.6Sr0.4FeO3-δ has been studied with neutron diffraction. Oxygen vacancies were created by annealing samples under various gases including N2, air and mixtures of CO/CO2. All La0.6Sr0.4FeO3-δ compounds maintain the rhombohedral structure (space group R3̄c). The air- or oxygen-annealed samples have almost no oxygen …

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Neutron Powder Diffraction Studies Of The La0.65Pb0.35Mno3 Perovskite, Camelia Borca, Shireen Adenwalla, Sy-Hwang Liou, Q.L. Xu, J. L. Robertson, Peter A. Dowben Jan 2002

Neutron Powder Diffraction Studies Of The La0.65Pb0.35Mno3 Perovskite, Camelia Borca, Shireen Adenwalla, Sy-Hwang Liou, Q.L. Xu, J. L. Robertson, Peter A. Dowben

Peter Dowben Publications

The structure of La0.65Pb0.35MnO3 has been studied by neutron powder diffraction. From the temperature dependence of the lattice parameters, we observe that La0.65Pb0.35MnO3 remains single phase in the temperature interval from 25 to 400 K, with a rhombohedral (R3c) structure. The collinear Mn spins suffer a thermally driven reorientation transition close to the Curie temperature, as obtained from powder samples (using neutron diffraction) and from thin films [using ferromagnetic resonance (FMR)]. The reorientation transition may indicate the presence of local Jahn–Teller (JT) lattice distortions, which are prevented from …

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Structural Transition In (C60)N Clusters, W. Branz, N. Malinowski, Axel Enders, T. P. Martin Jan 2002

Structural Transition In (C60)N Clusters, W. Branz, N. Malinowski, Axel Enders, T. P. Martin

Axel Enders Publications

The structure of (C60) n clusters (n = 1– 150) was investigated by heating them to definite temperatures in a helium bath (heating cell) with subsequent characterization in a time-of-flight mass spectrometer. The intensity anomalies in the resulting mass spectra reflect particularly stable configurations that resisted evaporation. However, the set of enhanced peaks (magic numbers) turned out to be temperature dependent. Clusters heated to a moderate temperature of 490 K yielded mass spectra indicating the presence of icosahedral structures that can be characterized by a set of unusually strong peaks, namely n = 13, 19, 23, 26, …

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Adsorbate And Thermally Induced Spin Reorientation Transition In Low-Temperature-Grown Fe/Cu(001), D. Peterka, Axel Enders, G. Haas, K. Kern Jan 2002

Adsorbate And Thermally Induced Spin Reorientation Transition In Low-Temperature-Grown Fe/Cu(001), D. Peterka, Axel Enders, G. Haas, K. Kern

Axel Enders Publications

Adsorbate and thermally induced changes of the spin reorientation transition in Fe wedges grown at 140 K on Cu(001) substrates are investigated by the magneto-optical Kerr effect and Kerr microscopy. The adsorption of oxygen causes a complete reorientation of the easy axis of magnetization into the film plane. In contrast to that carbon monoxide decreases the critical thickness for the reorientation transition of the film by 0.7 monolayer down to 3.6 monolayers, while films thinner than 3.6 monolayers remain magnetized perpendicularly. These adsorbate-induced changes can be ascribed to a change in the surface magnetic anisotropy. Also annealing of the films …

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The Magnetism-Nanostructure Interface In Advanced Magnetic Materials, David J. Sellmyer Jan 2002

The Magnetism-Nanostructure Interface In Advanced Magnetic Materials, David J. Sellmyer

David Sellmyer Publications

The critical relationship between microstructure and nanostructure of materials and their magnetic properties has been appreciated for decades. Electromagnetic machinery, permanent magnets, and data recording and electronic devices all have seen steady and sometimes spectacular advances over this period. At the present time the most interesting research in magnetism and magnetic materials arises from new developments in structuring materials on the nanometer length scale. This talk will present recent advances and challenges in furthering this work, with particular attention paid to extremely high density magnetic recording films, exchange-coupled high-energy-product permanent-magnet materials, high-temperature permanent-magnet materials, and self-organized and patterned magnetic nanoarrays.

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Elemental Mapping Of Co-Pr Nanostructured Powders By Eels Image Filtering, Yi Liu, C. Nelson, H. Tang, David J. Sellmyer Jan 2002

Elemental Mapping Of Co-Pr Nanostructured Powders By Eels Image Filtering, Yi Liu, C. Nelson, H. Tang, David J. Sellmyer

David Sellmyer Publications

In current extremely high density recording media design, the signal to noise ratio SNR is related to the number of magnetic grains N in a recording bit by
SNR = 10 logl0 N .................................... (1)
In earlier studies we have found that a metallurgical grain can act as a magnetic grain when grains are magnetically decoupled by a non-magnetic phase [1,2]. Alternatively, several metallurgical grains can be exchange-coupled together when they are small [3]. An ideal morphology is one in which the non-magnetic atoms are segregated at the grain boundaries forming the non-magnetic phase while keeping the grains closely …

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Determination Of Hexadecapole Moments For The 3p4(1D) Core Of Argon Ii Excited In Polarized E--Ar Collisions, B. G. Birdsey, H. M. Al-Khateeb, Timothy J. Gay Jan 2002

Determination Of Hexadecapole Moments For The 3p4(1D) Core Of Argon Ii Excited In Polarized E--Ar Collisions, B. G. Birdsey, H. M. Al-Khateeb, Timothy J. Gay

Timothy J. Gay Publications

We report on measurements of the integrated Stokes parameters of the light emitted from four well-LS coupled states of the 3p4(1D)4p manifold of Aril, following the simultaneous ionization and excitation of neutral argon by polarized electrons. As for all states, the state multipoles of J can be expanded in terms of the total orbital (L ) and the total spin (S) state multipoles. By splitting each L and S state multipole into multipoles for the core and outer electron, we have experimentally obtained for the first time the normalized integrated state multipole of rank 4 (hexadecapole …

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Progress With Optically Pumped Sources Of Polarized Electrons, Mark A. Rosenberry, Herman Batelaan, J. P. Reyes, Timothy J. Gay Jan 2002

Progress With Optically Pumped Sources Of Polarized Electrons, Mark A. Rosenberry, Herman Batelaan, J. P. Reyes, Timothy J. Gay

Timothy J. Gay Publications

We report our work in developing new "turn-key" sources of polarized electrons. These sources operate by extracting the electrons from a discharge and polarizing them through optical pumping. Preliminary work demonstrates that beams of 4 μA with greater than 20% polarization are possible. Such devices could enormously simplify the running of many experiments in the fields of atomic structure, magnetic materials and biophysics.

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Women In Physics In The United States, Megan Urry, Sheila Tobias, Kim Budil, Howard Georgi, Kristine Lang, Dongqi Li, Laurie Mcneil, Peter N. Saeta, Jennifer Sokoloski, Sharon Stephenson, Aparna Venkatesan, Yevgeniya Zastavker Jan 2002

Women In Physics In The United States, Megan Urry, Sheila Tobias, Kim Budil, Howard Georgi, Kristine Lang, Dongqi Li, Laurie Mcneil, Peter N. Saeta, Jennifer Sokoloski, Sharon Stephenson, Aparna Venkatesan, Yevgeniya Zastavker

All HMC Faculty Publications and Research

Presents an overview of the status of women in physics in the U.S. Under-representation of women; Highlights of the report 'Women in Physics, 2000'; Efforts to increase the number of women in the profession; Issues for women activists.

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The Large M Limit Of Non-Commutative Open Strings At Strong Coupling, Vatche Sahakian Jan 2002

The Large M Limit Of Non-Commutative Open Strings At Strong Coupling, Vatche Sahakian

All HMC Faculty Publications and Research

Two-dimensional Non-Commutative Open String (NCOS) theory, well-defined perturbatively, may also be studied at strong coupling and for large D-string charge by making use of the Holographic duality. We analyze the zero mode dynamics of a closed string in the appropriate background geometry and map the results onto a sector of strongly coupled NCOS dynamics. We find an elaborate classical picture that shares qualitative similarities with the SL(2,R) WZW model. In the quantum problem, we compute propagators and part of the energy spectrum of the theory; the latter involves interesting variations in the density of states as a function …

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Fiber Optic Sensor Response To High Levels Of Fat In Cream, Czarena L. Crofcheck, Frederick A. Payne, Clair L. Hicks, M. Pinar Mengüç, Sue E. Nokes Jan 2002

Fiber Optic Sensor Response To High Levels Of Fat In Cream, Czarena L. Crofcheck, Frederick A. Payne, Clair L. Hicks, M. Pinar Mengüç, Sue E. Nokes

Biosystems and Agricultural Engineering Faculty Publications

A light backscatter technique using optical fibers to deliver and receive light was investigated for measuring the milkfat content of unhomogenized cream. Light backscatter through cream at wavelengths of 450 to 900 nm was measured for fiber separation distances from 2 to 6.5 mm and for cream containing 10 to ~40 weight percent (wt%) milkfat. Unhomogenized cream (~40 wt% milkfat) was mixed with skim milk (~0.05 wt% milkfat) to yield samples with five different milkfat levels. Three optical response models were tested for correlation with milkfat content: one using the light intensity measurement at a single separation distance, the second …

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Optical And Magnetic Behaviour Of Low Dimensional Structures, Francis Pedreschi Jan 2002

Optical And Magnetic Behaviour Of Low Dimensional Structures, Francis Pedreschi

Doctoral

Low dimensional structures can exhibit unusual properties due to the quantum confinement of electrons. This may manifest itself in any effects that depend on electron behaviour. In this study, the optical and magnetic properties in particular of two types of low dimensional structures are examines. Quantum wires are structures that have macroscopic length scales along one dimension and nanometre length scales in the others. Two Indium induced reconstructions of Silicon surfaces were grown and examined to determine if quantum confinement, a necessary requirement for a quantum wire, did exist for their structures. A UHV compatible Reflectance Anisotropy Spectroscopy (RAS) instrument, …

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