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Articles 1651 - 1680 of 2944

Full-Text Articles in Astrophysics and Astronomy

Dilute Magnetism And Spin-Orbital Percolation Effects In Sr2Ir1−XRhXO4, J. P. Clancy, A. Lupascu, H. Gretarsson, Z. Islam, Y. F. Hu, D. Casa, C. S. Nelson, S. C. Lamarra, Gang Cao, Young-June Kim Feb 2014

Dilute Magnetism And Spin-Orbital Percolation Effects In Sr2Ir1−XRhXO4, J. P. Clancy, A. Lupascu, H. Gretarsson, Z. Islam, Y. F. Hu, D. Casa, C. S. Nelson, S. C. Lamarra, Gang Cao, Young-June Kim

Physics and Astronomy Faculty Publications

We have used a combination of resonant magnetic x-ray scattering and x-ray absorption spectroscopy to investigate the properties of the doped spin-orbital Mott insulator Sr2Ir1−xRhxO4 (0.07 ≤ x ≤ 0.70). We show that Sr2Ir1−xRhxO4 represents a unique model system for the study of dilute magnetism in the presence of strong spin-orbit coupling, and provide evidence of a doping-induced change in magnetic structure and a suppression of magnetic order at xc ∼ 0.17. We demonstrate that Rh-doping introduces Rh3+/Ir5+ ions which …

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Novel Magnetism Of Ir5+(5D4) Ions In The Double Perovskite Sr2Yiro6, Gang Cao, Tongfei Qi, Li Li, Jsaminka Terzic, Shujuan Yuan, Lance E. De Long, Ganpathy Murthy, Ribhu K. Kaul Feb 2014

Novel Magnetism Of Ir5+(5D4) Ions In The Double Perovskite Sr2Yiro6, Gang Cao, Tongfei Qi, Li Li, Jsaminka Terzic, Shujuan Yuan, Lance E. De Long, Ganpathy Murthy, Ribhu K. Kaul

Physics and Astronomy Faculty Publications

We synthesize and study single crystals of a new double-perovskite Sr2YIrO6. Despite two strongly unfavorable conditions for magnetic order, namely, pentavalent Ir5+(5d4) ions which are anticipated to have Jeff=0 singlet ground states in the strong spin-orbit coupling (SOC) limit and geometric frustration in a face-centered cubic structure formed by the Ir5+ ions, we observe this iridate to undergo a novel magnetic transition at temperatures below 1.3 K. We provide compelling experimental and theoretical evidence that the origin of magnetism is in an unusual interplay between strong noncubic crystal …

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Deposition And Analysis Of Copper Indium Disulfide For Photovoltaic Applications, Frederick Wade Jan 2014

Deposition And Analysis Of Copper Indium Disulfide For Photovoltaic Applications, Frederick Wade

Macalester Journal of Physics and Astronomy

Thin Film semiconductors were created through the methods of electrochemistry to produce a copper, indium and sulfur metal alloy that could be placed on a stainless steel substrate. We observed other properties regarding the relative indium to copper relationships and both the macro and micro structure of the final product. X-­‐ray diffraction, SEM imaging, and atomic absorption spectroscopy data suggest a relatively intact metal alloy, but also an inaccurate ratio of indium to copper.

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Photometric And Spectroscopic Analysis Of Young, Nearby Open Cluster Collinder 70, Clara M. Thomann Jan 2014

Photometric And Spectroscopic Analysis Of Young, Nearby Open Cluster Collinder 70, Clara M. Thomann

Macalester Journal of Physics and Astronomy

We present the results of a wide-field (80’ x 80’) photometric and spectroscopic survey of the young open cluster Collinder 70, which is also known as the ORI OB 1b association, centered on the central star of Orion’s belt, ε Ori (Alnilam). Seventy Coll 70 spectroscopy targets were selected from BVRIc color magnitude diagrams for observation using the CTIO HYDRA multi-object spectrograph; we aimed to identify targets exhibiting H" in emission and a strong lithium 6708Å line in absorption. About a third of our targets (23/70 stars) are consistent with being youthful members of Coll 70. Intermediate resolution (R!20000) HYDRA …

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Monte Carlo Simulation For Silicon On Silane Hwcvd For Thin Film Solar Cells, Annaleigh Smith Jan 2014

Monte Carlo Simulation For Silicon On Silane Hwcvd For Thin Film Solar Cells, Annaleigh Smith

Macalester Journal of Physics and Astronomy

Thin film solar cells offer a viable alternative to crystal silicon solar cells. They are expected to be cheaper to fabricate because they use material more efficiently, and are deposited in a process which can create larger area solar cells [1]. However, a high deposition rate is necessary for economic viability. A Monte Carlo simulation can model the molecular interactions in hot wire chemical vapor deposition and track the position and velocity distribution of molecular species in the gas [2]. Determining the flux on the substrate can help us to increase deposition rate by adjusting control parameters accordingly [3]. As …

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Galaxy Merger Identification In The Goods-South Field, Erin O'Leary Jan 2014

Galaxy Merger Identification In The Goods-South Field, Erin O'Leary

Macalester Journal of Physics and Astronomy

We analyzed a catalog of 7,628 galaxies at 0 < z < 4 from CANDELS1 in the GOODS-South2 field in order to identify a sample of galaxy mergers and interactions. Galaxy mergers are believed to play a fundamental role in galaxy evolution. Developing methods to robustly and efficiently identify mergers becomes vital with our increasing ability to study mergers at higher redshifts and in larger samples. We explored merger identification based on visual morphology classification and preliminary attempts with automated quantitative methods. Using multiple detailed visual morphology classifications for each galaxy conducted by the CANDELS structure and morphology team, we created selection criteria to …

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Shield: Star Formation From Wiyn And Galex Imaging, Samilee J. Moody Jan 2014

Shield: Star Formation From Wiyn And Galex Imaging, Samilee J. Moody

Macalester Journal of Physics and Astronomy

Using images from the GALEX (Galaxy Evolution Explorer) GR6 pipeline (released 2010), as well as the WIYN 3.5m Observatory, we present a survey of the twelve SHIELD galaxies in the far-ultraviolet (FUV, 1500 Å) and near-ultraviolet (NUV, 2200 Å) filters. FUV data were available for eleven of the galaxies, AGC 749237 being the exception. Aperture photometry was performed on each image to determine the AB magnitude in the FUV and NUV filters.These values were then used to calculate flux, luminosity, and star formation rates (SFRs). Similarly, Hα images of each galaxy from WIYN (omitting AGC 749241) were analyzed to determine …

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Numerical Modeling Of The Finite Well With Implications For Observing Quantum Interference Between Coherent Electron Wave, Jacob M. Moen Jan 2014

Numerical Modeling Of The Finite Well With Implications For Observing Quantum Interference Between Coherent Electron Wave, Jacob M. Moen

Macalester Journal of Physics and Astronomy

We use numerical modeling in Fortran to investigate the claims of Wollenhaupt et al. (2006) and Hommelhoff et al. (2002) regarding ultra-­short electron pulses ionized via laser excitation of a tungsten nanotip. We assume that the nanotip acts as a finite one‐dimensional potential well with the depth equal to the work function of tungsten and the width of the order of the radius of curvature of the nanotip. The interactions of propagating Gaussian wave packets are modeled in order to give insight into the temporal and spatial evolution of the generated electron wave packets. Furthermore we hope to demonstrate the …

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Synthesis And Characterization Of Zinc-­‐Oxide/Polystyrene Nanocomposite Thin Films, Christopher Krapu Jan 2014

Synthesis And Characterization Of Zinc-­‐Oxide/Polystyrene Nanocomposite Thin Films, Christopher Krapu

Macalester Journal of Physics and Astronomy

Ultra-thin films containing zinc oxide and polystyrene were prepared by sol-gel mixing and spincoating onto silicon substrate. Photoluminescent measurements were recorded following irradiation at 325 nm. We observed passivation of shallow defect states around 3.1 eV bandgap via confinement. Time-resolved photoluminescence plots suggest a significant time dependence of emission intensity related to photodegradation of the polymer matrix.

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Light-By-Light Scattering Nonlogarithmic Corrections To Hyperfine Splitting In Muonium, Michael I. Eides, Valery A. Shelyuto Jan 2014

Light-By-Light Scattering Nonlogarithmic Corrections To Hyperfine Splitting In Muonium, Michael I. Eides, Valery A. Shelyuto

Physics and Astronomy Faculty Publications

We consider three-loop corrections to hyperfine splitting in muonium generated by the gauge invariant set of diagrams with a virtual light-by-light scattering block. These diagrams produce both recoil and nonrecoil contributions to hyperfine splitting. Recoil corrections are enhanced by large logarithms of the muon-electron mass ratio. Both nonrecoil and logarithmically enhanced radiative-recoil corrections were calculated some time ago. Here we calculate nonlogarithmic radiative-recoil corrections generated by the insertions of the light-by-light scattering block.

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Growth Kinetics Of Zno By Magnetron Sputtering For Solar Cell Application, Nadia Foo Kune Jan 2014

Growth Kinetics Of Zno By Magnetron Sputtering For Solar Cell Application, Nadia Foo Kune

Macalester Journal of Physics and Astronomy

The goal of this work is study the mechanism of ZnO thin film deposition by rf magnetron sputtering with an argon plasma. This research will help understand the growth kinetics of the ZnO layer in relation to the growth conditions for solar cell application. We study the rate of growth, the electrical properties, the optical transmission and the zinc to oxygen ratio of each sample as a function of growth temperature. We conclude that Zn evaporation competes with incorporation into the film by combining with an arriving O atom.

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Tip-Of-The-Red-Giant-Branch Detection: Estimating The Distance To Resolved Galaxies In Shield, Ian Cave Jan 2014

Tip-Of-The-Red-Giant-Branch Detection: Estimating The Distance To Resolved Galaxies In Shield, Ian Cave

Macalester Journal of Physics and Astronomy

The Survey of HI in Extremely Low-mass Dwarfs (SHIELD) is an ongoing study of twelve galaxies with HI masses between 106 and 107 Solar masses, detected by the Arecibo Legacy Fast ALFA (ALFALFA) survey. One of the important characteristics of a galaxy is its distance, since knowing that value allows us to calibrate many other factors and learn more about the galaxy. This research was focused on creating a program to systematically solve for the distance to the galaxies in SHIELD. To perform this calculation, Tip-of-the-Red-Giant-Branch (TRGB) detection was chosen, which is a popular method for galaxies with …

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Electrical Conductivity Of Tellurium Nanowires On Pedot:Pss, Banteaymolu Alebachew Jan 2014

Electrical Conductivity Of Tellurium Nanowires On Pedot:Pss, Banteaymolu Alebachew

Macalester Journal of Physics and Astronomy

The purpose of this project is to understand the electrical conductivity and infrared absorption spectrum of a hybrid material between Tellurium nanowires and a carbon polymer called PEDOT:PSS. This hybrid material shows much higher conductivity than its components and this behavior gives a great promise for thermoelectric effect. The most intriguing property of this material is observed when taking absorption spectrum from far to near infrared. The hybrid material shows a much bigger absorption edge than Te NW. This project attempts to explain this shift using the confinement energy model and Fermi blocking (due to doping). The result from these …

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Sub-Sonic Open-Return Wind-Tunnel And Measurement Apparatus, Michael Adams Jan 2014

Sub-Sonic Open-Return Wind-Tunnel And Measurement Apparatus, Michael Adams

Macalester Journal of Physics and Astronomy

Wind tunnels are an effective tool for understanding relationships between predicted and actual behavior of air foils in laminar flow. In order to improve the ability of Macalester College staff and students to observe and experiment with the effects of laminar air flow on various objects and systems, it was necessary to construct and test a sub-sonic open return wind tunnel. The purpose of the tests was to discover whether or not the air flow through the test section of the tunnel was laminar around the object being tested and also to evaluate the quality of an apparatus constructed to …

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Energy Dependence Of Moments Of Net-Proton Multiplicity Distributions At Rhic, James K. Atkins, Renee H. Fatemi, Wolfgang Korsch, Suvarna Ramachandran, G. Webb, L. Adamczyk, G. Agakishiev, M. M. Aggarwal, Z. Ahammed, I. Alekseev, J. Alford, C. D. Anson, A. Aparin, D. Arkhipkin, E. C. Aschenauer, G. S. Averichev, J. Balewski, A. Banerjee, Z. Barnovska, D. R. Beavis, R. Bellwied, A. Bhasin, A. K. Bhati, P. Bhattarai, H. Bichsel, J. Bielcik, J. Bielcikova, L. C. Bland, I. G. Bordyuzhin, W. Borowski Jan 2014

Energy Dependence Of Moments Of Net-Proton Multiplicity Distributions At Rhic, James K. Atkins, Renee H. Fatemi, Wolfgang Korsch, Suvarna Ramachandran, G. Webb, L. Adamczyk, G. Agakishiev, M. M. Aggarwal, Z. Ahammed, I. Alekseev, J. Alford, C. D. Anson, A. Aparin, D. Arkhipkin, E. C. Aschenauer, G. S. Averichev, J. Balewski, A. Banerjee, Z. Barnovska, D. R. Beavis, R. Bellwied, A. Bhasin, A. K. Bhati, P. Bhattarai, H. Bichsel, J. Bielcik, J. Bielcikova, L. C. Bland, I. G. Bordyuzhin, W. Borowski

Physics and Astronomy Faculty Publications

We report the beam energy(√8NN = 7.7-200 GeV) and collision centrality dependence of the mean (M), standard deviation (σ), skewness (S), and kurtosis (κ) of the net-proton multiplicity distributions in Au+Au collisions. The measurements are carried out by the STAR experiment at midrapidity (|y|<0.5) and within the transverse momentum range 0.4<ρτ<0.8  GeV/c in the first phase of the Beam Energy Scan program at the Relativistic Heavy Ion Collider. These measurements are important for understanding the quantum chromodynamic phase diagram. The products of the moments, Sσ and κσ2, are sensitive to the correlation length of the hot and dense …

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Interpreting The Ionization Sequence In Agn Emission-Line Spectra, Chris T. Richardson, James T. Allen, Jack A. Baldwin, Paul C. Hewett, Gary J. Ferland Jan 2014

Interpreting The Ionization Sequence In Agn Emission-Line Spectra, Chris T. Richardson, James T. Allen, Jack A. Baldwin, Paul C. Hewett, Gary J. Ferland

Physics and Astronomy Faculty Publications

We investigate the physical cause of the great range in the ionization level seen in the spectra of narrow-lined active galactic nuclei (AGN). We used a recently developed technique called mean field independent component analysis to identify examples of individual Sloan Digital Sky Survey galaxies whose spectra are not dominated by emission due to star formation (SF), which we therefore designate as AGN. We assembled high signal-to-noise ratio (S/N) composite spectra of a sequence of these AGN defined by the ionization level of their narrow-line regions (NLR), and extending down to very low ionization cases. We then used a local …

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Self-Heating Model Of Spherical Aluminum Nanoparticle Oxidation, Karen S. Martirosyan, Zamart Ramazanova, Maxim Zyskin Jan 2014

Self-Heating Model Of Spherical Aluminum Nanoparticle Oxidation, Karen S. Martirosyan, Zamart Ramazanova, Maxim Zyskin

Physics & Astronomy Faculty Publications

Aluminum-oxygen reaction is important in highly energetic and high pressure generating systems. Nanoenergetic thermites include mixtures of nanostructured Al and oxidizer particles. The main distinguishing features of these reactive systems are their significant enthalpy release and tunable rate of energy discharge, which gives rise to a wide range of combustion rates, energy release, and ignition sensitivity. In this paper, we consider rapid oxidation of a spherically symmetric aluminum particle. We use the Cabrera Mott oxidation model to describe the kinetics of oxide growth of an aluminum nanoparticle and to predict reaction temperature and oxidation time. We assume that aluminum particle …

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Neutral Pion Cross Section And Spin Asymmetries At Intermediate Pseudorapidity In Polarized Proton Collisions At √S=200  Gev, L. Adamczyk, James K. Adkins, G. Agakishiev, M. M. Aggarwal, Z. Ahammed, I. Alekseev, J. Alford, C. D. Anson, A. Aparin, D. Arkhipkin, Renee H. Fatemi, Robert G. Fersch, Wolfgang Korsch, Suvarna Ramachandran, G. Webb Jan 2014

Neutral Pion Cross Section And Spin Asymmetries At Intermediate Pseudorapidity In Polarized Proton Collisions At √S=200  Gev, L. Adamczyk, James K. Adkins, G. Agakishiev, M. M. Aggarwal, Z. Ahammed, I. Alekseev, J. Alford, C. D. Anson, A. Aparin, D. Arkhipkin, Renee H. Fatemi, Robert G. Fersch, Wolfgang Korsch, Suvarna Ramachandran, G. Webb

Physics and Astronomy Faculty Publications

The differential cross section and spin asymmetries for neutral pions produced within the intermediate pseudorapidity range 0.8<ηpT/c and is found to agree with a next-to-leading order perturbative QCD calculation. The longitudinal double-spin asymmetry ALL is measured in the same pseudorapidity range and spans a range of Bjorken-x down to x≈0.01. The measured ALL is consistent with model predictions for varying degrees of gluon polarization. The parity-violating asymmetry AL is also measured and found to be consistent with zero. The transverse single-spin asymmetry AN is measured over a previously unexplored kinematic range in …

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Energy Dependence Of The (E,2E) Recoil Peak To Binary Peak Ratio Across He (2P2)1D And (2S2P)1P Autoionizing Levels, B. A. Deharak, K. Bartschat, Nicholas L. S. Martin Jan 2014

Energy Dependence Of The (E,2E) Recoil Peak To Binary Peak Ratio Across He (2P2)1D And (2S2P)1P Autoionizing Levels, B. A. Deharak, K. Bartschat, Nicholas L. S. Martin

Physics and Astronomy Faculty Publications

The (e,2e) recoil peak to binary peak ratio as a function of the ejected-electron energy is reported for helium autoionizing levels (2p2)1D and (2s2p)1P. A special out-of-plane geometry is used where the ejected electrons are detected in a plane that includes the momentum transfer axis but is perpendicular to the scattering plane. The measured recoil peak to binary peak ratio is a dimensionless quantity that can be directly compared with calculations. A second-order model in the projectile-target interaction correctly reproduces the observed energy dependence …

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Annual Solar Motion And Spy Satellites, Margaret Jensen, Shane L. Larson Jan 2014

Annual Solar Motion And Spy Satellites, Margaret Jensen, Shane L. Larson

Browse All Undergraduate research

A topic often taught in introductory astronomy courses is the changing position of the Sun in the sky as a function of time of day, and season. The relevance and importance of this motion is explained in the context of seasons and the impact it has on human activities such as agriculture. The geometry of the ob- served motion in the sky is usually reduced to graphical representations and visualizations that can be difficult to render and grasp. Sometimes students are asked to observe the Suns changing motion and record their data, but this is a long-term project requiring several …

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Studying Short-Period Comets And Long-Period Comets Detected By Wise/Neowise, Emily Kramer Jan 2014

Studying Short-Period Comets And Long-Period Comets Detected By Wise/Neowise, Emily Kramer

Electronic Theses and Dissertations

The Wide-field Infrared Survey Explorer (WISE) mission surveyed the sky in four infrared wavelength bands (3.4, 4.6, 12 and 22 μm) between January 2010 and February 2011. During the mission, WISE serendipitously observed 160 comets, including 21 newly discovered objects. About 89 of the comets observed by WISE displayed a significant dust tail in the 12 and 22 μm (thermal emission) bands, showing a wide range of activity levels and dust morphology. Since the observed objects are a mix of both long-period comets (LPCs) and short-period comets (SPCs), differences in their activity can be used to better understand the thermal …

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Surface Plasmon Resonance Sensing Properties Of A 3d Nanostructure Consisting Of Aligned Nanohole And Nanocone Arrays, Mohamadreza Najiminaini, Erden Ertorer, Bozena Kaminska, Silvia Mittler, Jeffrey J.L. Carson Jan 2014

Surface Plasmon Resonance Sensing Properties Of A 3d Nanostructure Consisting Of Aligned Nanohole And Nanocone Arrays, Mohamadreza Najiminaini, Erden Ertorer, Bozena Kaminska, Silvia Mittler, Jeffrey J.L. Carson

Physics and Astronomy Publications

Molecular surface plasmon resonance (SPR) sensing is one of the most common applications of an array of periodic nanoholes in a metal film. However, metallic nanohole arrays (NHAs) with low-hole count have lower resolution and SPR sensing performance compared to NHAs with high-hole count. In this paper, we present a compact three-dimensional (3D) plasmonic nanostructure with extraordinary optical transmission properties benefiting from surface plasmon matching and enhanced localized surface plasmon coupling. The 3D nanostructure consisted of a gold film containing a NHA with an underlying cavity and a gold nanocone array (NCA) at the bottom of the cavity. Each nanocone …

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A Transition Mass For Black Holes To Show Broad Emission Lines, Susmita Chakravorty, Martin Elvis, Gary J. Ferland Jan 2014

A Transition Mass For Black Holes To Show Broad Emission Lines, Susmita Chakravorty, Martin Elvis, Gary J. Ferland

Physics and Astronomy Faculty Publications

Although the supermassive (AGN) and stellar mass (BHBs) black holes have many properties in common, the broad emission lines (BELs) are exclusively signatures of the active galactic nuclei (AGN). Based on the detection of these lines from Sloan Digital Sky Survey (SDSS) data bases, there seems to be no AGN with mass MBH ≲ 105 M⊙. In this paper, we investigate if such low-mass black holes are really non-existent or they are undetected because the BELs in them are not produced efficiently. Using the ionizing spectral energy distribution for a wide range of black hole mass, …

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Suppression Of Dielectronic Recombination At Finite Densities, T. W. Gorczyca, D. Nikolić, N. R. Badnell, Gary J. Ferland Jan 2014

Suppression Of Dielectronic Recombination At Finite Densities, T. W. Gorczyca, D. Nikolić, N. R. Badnell, Gary J. Ferland

Physics and Astronomy Faculty Publications

Density-dependent effective dielectronic recombination rate coefficients are determined in order to explore finite-density effects on the ionization balance of plasmas.

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Unidirectional Lasing Emerging From Frozen Light In Nonreciprocal Cavities, Hamidreza Ramezani, S. Kalish, I. Vitebskiy, T. Kottos Jan 2014

Unidirectional Lasing Emerging From Frozen Light In Nonreciprocal Cavities, Hamidreza Ramezani, S. Kalish, I. Vitebskiy, T. Kottos

Physics & Astronomy Faculty Publications

We introduce a class of unidirectional lasing modes associated with the frozen mode regime of nonreciprocal slow-wave structures. Such asymmetric modes can only exist in cavities with broken timereversal and space inversion symmetries. Their lasing frequency coincides with a spectral stationary inflection point of the underlying passive structure and is virtually independent of its size. These unidirectional lasers can be indispensable components of photonic integrated circuitry.

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Higgs Effects In Neutrino Physics And Heavy Quark Systems, Ahmed Rashed Jan 2014

Higgs Effects In Neutrino Physics And Heavy Quark Systems, Ahmed Rashed

Electronic Theses and Dissertations

This work presents a study of the effects of multi-Higgs doublets on the properties of neutrino sector and heavy quark systems. The phenomenological implications of multi-Higgs models, which contain multi-Higgs doublets, in the neutrino and quark sector are discussed in this dissertation. The two-Higgs-doublet model (2HDM), in which two Higgs doublets are introduced, is the simplest extension to the scalar sector of the standard model (SM). A new boson state was recently seen in the CMS (Compact Muon Solenoid) and ATLAS (A Toroidal LHC Apparatus) experiments at the LHC (Large Hadron Collider). We investigate the multi-Higgs models contributions in understanding …

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Cold Gas Dynamics In Hydra-A: Evidence For A Rotating Disc, S. L. Hamer, A. C. Edge, A. M. Swinbank, J. B. R. Oonk, R. Mittal, B. R. Mcnamara, H. R. Russell, M. N. Bremer, F. Combes, A. C. Fabian, N. P. H. Nesvadba, C. P. O'Dea, S. A. Baum, P. Salomé, G. Tremblay, M. Donahue, Gary J. Ferland, C. L. Sarazin Jan 2014

Cold Gas Dynamics In Hydra-A: Evidence For A Rotating Disc, S. L. Hamer, A. C. Edge, A. M. Swinbank, J. B. R. Oonk, R. Mittal, B. R. Mcnamara, H. R. Russell, M. N. Bremer, F. Combes, A. C. Fabian, N. P. H. Nesvadba, C. P. O'Dea, S. A. Baum, P. Salomé, G. Tremblay, M. Donahue, Gary J. Ferland, C. L. Sarazin

Physics and Astronomy Faculty Publications

We present multifrequency observations of the radio galaxy Hydra-A (3C218) located in the core of a massive, X-ray luminous galaxy cluster. Integral field unit spectroscopy is used to trace the kinematics of the ionized and warm molecular hydrogen which are consistent with an ∼5 kpc rotating disc. Broad, double-peaked lines of CO(2–1), [C II] 157 μm and [O I] 63 μm are detected. We estimate the mass of the cold gas within the disc to be Mgas = 2.3 ± 0.3 × 109 M⊙. These observations demonstrate that the complex line profiles found in the cold …

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Neutral Pion Cross Section And Spin Asymmetries At Intermediate Pseudorapidity In Polarized Proton Collisions At √ S = 200 Gev, L. Adamczyk, J. K. Adkins, G. Agakishiev, M. M. Aggarwal, Z. Ahammed, I. Alekseev, S. Bültmann, I. Koralt, D. Plyku, Star Collaboration Jan 2014

Neutral Pion Cross Section And Spin Asymmetries At Intermediate Pseudorapidity In Polarized Proton Collisions At √ S = 200 Gev, L. Adamczyk, J. K. Adkins, G. Agakishiev, M. M. Aggarwal, Z. Ahammed, I. Alekseev, S. Bültmann, I. Koralt, D. Plyku, Star Collaboration

Physics Faculty Publications

The differential cross section and spin asymmetries for neutral pions produced within the intermediate pseudorapidity range 0.8<η/c and is found to agree with a next-to-leading order perturbative QCD calculation. The longitudinal double-spin asymmetry ALL is measured in the same pseudorapidity range and spans a range of Bjorken-x down to x≈0.01. The measured ALL is consistent with model predictions for varying degrees of gluon polarization. The parity-violating asymmetry AL is also measured and found to be consistent with zero. The transverse single-spin asymmetry AN is measured over a previously unexplored kinematic range in Feynman-x and PT. Such measurements may aid our understanding of the onset and kinematic dependence of the large asymmetries observed …

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Constraints On Cosmic Strings From The Ligo-Virgo Gravitational-Wave Detectors, Daniel Bessis, Teviet Creighton, H. Daveloza, Mario C. Diaz, Soma Mukherjee, Volker Quetschke, Malik Rakhmanov, Robert Stone, Lappoon R. Tang, Cristina V. Torres Jan 2014

Constraints On Cosmic Strings From The Ligo-Virgo Gravitational-Wave Detectors, Daniel Bessis, Teviet Creighton, H. Daveloza, Mario C. Diaz, Soma Mukherjee, Volker Quetschke, Malik Rakhmanov, Robert Stone, Lappoon R. Tang, Cristina V. Torres

Physics & Astronomy Faculty Publications

Cosmic strings can give rise to a large variety of interesting astrophysical phenomena. Among them, powerful bursts of gravitational waves (GWs) produced by cusps are a promising observational signature. In this Letter we present a search for GWs from cosmic string cusps in data collected by the LIGO and Virgo gravitational wave detectors between 2005 and 2010, with over 625 days of live time. We find no evidence of GW signals from cosmic strings. From this result, we derive new constraints on cosmic string parameters, which complement and improve existing limits from previous searches for a stochastic background of GWs …

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Biosensors And Nanobiosensors: Design And Applications, Ahmed Touhami Jan 2014

Biosensors And Nanobiosensors: Design And Applications, Ahmed Touhami

Physics & Astronomy Faculty Publications

The goal of this chapter is to cover the full scope of biosensors. It offers a survey of the principles, design, operation, and biomedical applications of the most popular types of biosensing devices in use today. By discussing recent research and future trends based on many excellent books and reviews, it is hoped to give the readers a comprehensive view on this fast growing field.

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