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Full-Text Articles in Physics

Suncircles: A Prose/Poem 12/18/2014, Charles Kay Smith Dec 2014

Suncircles: A Prose/Poem 12/18/2014, Charles Kay Smith

Charles Kay Smith

A current project is writing a book of poetry. The different kind of poetry I’m trying to write melds science, humanities, and aesthetic aims of clarity and a polished plain style with social consciousness. I’m uploading one of the poems in the collection as an example of the kind of poetry I’m trying to compose.


Intensities, Broadening And Narrowing Parameters In The Ν3 Band Of Methane, Et-Touhami Es-Sebbar, Aamir Farooq Aug 2014

Intensities, Broadening And Narrowing Parameters In The Ν3 Band Of Methane, Et-Touhami Es-Sebbar, Aamir Farooq

Dr. Et-touhami Es-sebbar

The P-branch of methane׳s ν3 band is probed to carry out an extensive study of the 2905–2908 cm−1 infrared spectral region. Absolute line intensities as well as N2-, O2-, H2-, He-, Ar- and CO2-broadening coefficients are determined for nine transitions at room temperature. Narrowing parameters due to the Dicke effect have also been investigated. A narrow emission line-width (~0.0001 cm−1) difference-frequency-generation (DFG) laser system is used as the tunable light source. To retrieve the CH4 spectroscopic parameters, Voigt and Galatry profiles were used to simulate the measured line shape of the individual transitions.


Basic Astronomy Labs, Terry L. Smith, Michael D. Reynolds, Jay S. Huebner Jul 2014

Basic Astronomy Labs, Terry L. Smith, Michael D. Reynolds, Jay S. Huebner

Jay S Huebner

Providing the tools and know-how to apply the principles of astronomy first-hand, these 43 laboratory exercises each contain an introduction that clearly shows budding astronomers why the particular topic of that lab is of interest and relevant to astronomy. About one-third of the exercises are devoted solely to observation, and no mathematics is required beyond simple high school algebra and trigonometry.Organizes exercises into six major topics—sky, optics and spectroscopy, celestial mechanics, solar system, stellar properties, and exploration and other topics—providing clear outlines of what is involved in the exercise, its purpose, and what procedures and apparatus are to be used. …


Absorption Cross-Section Measurements Of Methane, Ethane, Ethylene And Methanol At High Temperatures, Majed Alrefae, Et-Touhami Es-Sebbar, Aamir Farooq Jul 2014

Absorption Cross-Section Measurements Of Methane, Ethane, Ethylene And Methanol At High Temperatures, Majed Alrefae, Et-Touhami Es-Sebbar, Aamir Farooq

Dr. Et-touhami Es-sebbar

Mid-IR absorption cross-sections are measured for methane, ethane, ethylene and methanol over 2800–3400 cm−1 (2.9–3.6 μm) spectral region. Measurements are carried out using a Fourier-Transform-Infrared (FTIR) spectrometer with temperatures ranging 296–1100 K and pressures near atmospheric. As temperature increases, the peak cross-sections decrease but the wings of the bands increase as higher rotational lines appear. Integrated band intensity is also calculated over the measured spectral region and is found to be a very weak function of temperature. The absorption cross-sections of the relatively small fuels studied here show dependence on the bath gas. This effect is investigated by studying the …


Accordion Effect In Plasma Channels: Generation Of Tunable Comb-Like Electron Beams, Serge Y. Kalmykov, Bradley A. Shadwick, Isaac A. Ghebregziabher, Xavier Davoine, Remi Lehe, Agustin F. Lifschitz, Victor Malka May 2014

Accordion Effect In Plasma Channels: Generation Of Tunable Comb-Like Electron Beams, Serge Y. Kalmykov, Bradley A. Shadwick, Isaac A. Ghebregziabher, Xavier Davoine, Remi Lehe, Agustin F. Lifschitz, Victor Malka

Serge Youri Kalmykov

Propagating a short, relativistically intense laser pulse in a plasma channel makes it possible to generate comb-like electron beams for advanced radiation sources. The ponderomotive force of the leading edge of the pulse expels all electrons facing the pulse. The bare ions attract the ambient plasma electrons, forming a closed bubble of electron density confining the pulse tail. The cavity of electron density evolves slowly, in lock-step with the optical driver, and readily traps background electrons. The combination of a bubble (a self-consistently maintained, “soft” hollow channel) and a preformed channel forces transverse flapping of the laser pulse tail, causing …


Pubspectra To Do Data, George Mcnamara May 2014

Pubspectra To Do Data, George Mcnamara

George McNamara

PubSpectra raw data that I had in my "to do" folder to add to the PubSpectra data set but never did.

PubSpectra has over 2000 spectra in it (last updated 2006) in Excel "big file" format - the XLSX file inside the zip file at

http://works.bepress.com/gmcnamara/9/

Anyone is welcome to add and organize new data yourselves. I used Un-Scan-It from Silk Scientific (www.silkscientific.com).

More importantly, I strongly adopting my PubSpectra format of 1 nm wavelength intervals, with the row number corresponding to nm. For example, 400 nm data appears in row 400.

Much of Urse Utzinger's "Spectra Arizona" data,

http://www.spectra.arizona.edu/ …


Comparative Study Of In Situ N2 Rotational Raman Spectroscopy Methods For Probing Energy Thermalisation Processes During Spin-Exchange Optical Pumping, Hayley Newton, Laura L. Walkup, Nicholas Whiting, Linda West, James Carriere, Frank Havermeyer, Lawrence Ho, Peter Morris, Boyd M. Goodson, Michael J. Barlow Apr 2014

Comparative Study Of In Situ N2 Rotational Raman Spectroscopy Methods For Probing Energy Thermalisation Processes During Spin-Exchange Optical Pumping, Hayley Newton, Laura L. Walkup, Nicholas Whiting, Linda West, James Carriere, Frank Havermeyer, Lawrence Ho, Peter Morris, Boyd M. Goodson, Michael J. Barlow

Nicholas Whiting

Spin-exchange optical pumping (SEOP) has been widely used to produce enhancements in nuclear spin polarisation for hyperpolarised noble gases. However, some key fundamental physical processes underlying SEOP remain poorly understood, particularly in regards to how pump laser energy absorbed during SEOP is thermalised, distributed and dissipated. This study uses in situ ultra-low frequency Raman spectroscopy to probe rotational temperatures of nitrogen buffer gas during optical pumping under conditions of high resonant laser flux and binary Xe/N2 gas mixtures. We compare two methods of collecting the Raman scattering signal from the SEOP cell: a conventional orthogonal arrangement combining intrinsic spatial filtering …


Solvent Dependency Of Azobenzene Thermal Relaxation, Chris Corkery, Alexis Goulet-Hanssens, Janet R. Belliveau, Mark Cronin-Golomb, Christopher J. Barrett Apr 2014

Solvent Dependency Of Azobenzene Thermal Relaxation, Chris Corkery, Alexis Goulet-Hanssens, Janet R. Belliveau, Mark Cronin-Golomb, Christopher J. Barrett

Chris Corkery

No abstract provided.


Physical Processes At Work In Sub-30fs, Pw Laser Pulse-Driven Plasma Accelerators: Towards Gev Electron Acceleration Experiments At Cilex Facility., Arnaud Beck, Serge Y. Kalmykov, Xavier Davoine, Agustin F. Lifschitz, Bradley A. Shadwick, Victor Malka, Arnd E. Specka Feb 2014

Physical Processes At Work In Sub-30fs, Pw Laser Pulse-Driven Plasma Accelerators: Towards Gev Electron Acceleration Experiments At Cilex Facility., Arnaud Beck, Serge Y. Kalmykov, Xavier Davoine, Agustin F. Lifschitz, Bradley A. Shadwick, Victor Malka, Arnd E. Specka

Serge Youri Kalmykov

Optimal regimes and physical processes at work are identified for the first round of laser wakefield acceleration experiments proposed at a future CILEX facility. The Apollon-10P CILEX laser, delivering fully compressed, near-PW-power pulses of sub-25 fs duration, is well suited for driving electron density wakes in the blowout regime in cm-length gas targets. Early destruction of the pulse (partly due to energy depletion)prevents electrons from reaching dephasing, limiting the energy gain to about 3 GeV. However, the optimal operating regimes, found with reduced and full three-dimensional particle-in-cell simulations, show high energy efficiency, with about 10%of incident pulse energy transferred to …


All-Optical Control Of Electron Self-Injection In Millimeter-Scale, Tapered Dense Plasmas., Serge Y. Kalmykov, Xavier Davoine, Bradley A. Shadwick Feb 2014

All-Optical Control Of Electron Self-Injection In Millimeter-Scale, Tapered Dense Plasmas., Serge Y. Kalmykov, Xavier Davoine, Bradley A. Shadwick

Serge Youri Kalmykov

It is demonstrated that a laser pulse with an ultrahigh bandwidth (400 nm) is an asset for future high-repetition-rate , quasimonoenergetic (QME), GeV-scale laser plasma electron accelerators. Manipulating the phase of the driver has a direct impact on evolution of the accelerating bucket (a cavity of electron density maintained by the pressure of the laser pulse radiation), making it possible to control electron self-injection and the final parameters of the QME beam by purely optical means. The large bandwidth makes it possible to compensate for the frequency red-shift accumulated at the pulse leading edge in transit through the plasma. Advancing …