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Articles 181 - 203 of 203

Full-Text Articles in Physical Sciences and Mathematics

An Electrochemical Study Of The Effects Of Chelating Agents And Additives On Electroless Copper Plating, Xin Gu, Zhou-Cheng Wang, Chang-Jian Lin Feb 2004

An Electrochemical Study Of The Effects Of Chelating Agents And Additives On Electroless Copper Plating, Xin Gu, Zhou-Cheng Wang, Chang-Jian Lin

Journal of Electrochemistry

In this study, ethylenediaminetetraacetic acid disodium salt (Na_2EDTA), triethanolamine(TEA), and 2,2′-dipyridine were adopted as chelating agents or additives in the electrolyte for electroless copper plating, and formaldehyde (HCHO) was as the reducting agent. Linear sweep voltammetry was applied to analyze the polarization behavior. The peak current of formaldehyde oxidation which increased by the addition of 2,2′-dipyridine is beneficial to formaldehyde oxidation in a specific range of concentration, While TEA decreased the peak current of formaldehyde oxidation. Two cathodic peaks due to copper(Ⅱ)reduction of TEA chelatation and copper(Ⅱ)reduction of EDTA chelatation were examined. EDTA increased the reduction peak current of Cu-EDTA …

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A Test Of Bell’S Inequality For The Undergraduate Laboratory, Burton A. Betchart Jan 2004

A Test Of Bell’S Inequality For The Undergraduate Laboratory, Burton A. Betchart

Honors Papers

The thesis documents the work done over the year to initiate an undergraduate Advanced Laboratory experiment which tests Bell’s inequality. It provides reference theory for the experiment, including explanations of Bell inequalities, basics of nonlinear optics, type-I downconversion and entanglement, and polarization states of the entangled photons. A main result is the equipment and design proposal for the experiment, which will cost a total $19600, led in price by the $9000 of a four photodetector array and followed by the $5000 of a 405nm pump laser. Entangled photons are produced by pumping BBO in a two-crystal geometry. Although most of …

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Complete Angular Distribution Measurements Of Two-Body Deuteron Photodisintegration Between 0.5 And 3 Gev, H. Bagdasaryan, H. Bektasoglu, G. E. Dodge, T. A. Forest, C. E. Hyde-Wright, A. Klein, A. V. Klimenko, S. E. Kuhn, F. Sabatié, S. Stepanyan, L. B. Weinstein, J. Yun, Et Al., The Clas Collaboration Jan 2004

Complete Angular Distribution Measurements Of Two-Body Deuteron Photodisintegration Between 0.5 And 3 Gev, H. Bagdasaryan, H. Bektasoglu, G. E. Dodge, T. A. Forest, C. E. Hyde-Wright, A. Klein, A. V. Klimenko, S. E. Kuhn, F. Sabatié, S. Stepanyan, L. B. Weinstein, J. Yun, Et Al., The Clas Collaboration

Physics Faculty Publications

Nearly complete angular distributions of the two-body deuteron photodisintegration differential cross section have been measured using the CEBAF Large Acceptance Spectrometer detector and the tagged photon beam at the Thomas Jefferson National Accelerator Facility. The data cover photon energies between 0.5 and 3.0 GeV and center-of-mass proton scattering angles 10°–160°. The data show a persistent forward-backward angle asymmetry over the explored energy range, and are well described by the nonperturbative quark gluon string model.

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Influence Of Antenna Aiming On Ece In Mast, Josef Preinhaelter, Jakub Urban, Pavol Pavlo, Vladimir Shevchenko, Martin Valovič, Linda L. Vahala, George Vahala Jan 2004

Influence Of Antenna Aiming On Ece In Mast, Josef Preinhaelter, Jakub Urban, Pavol Pavlo, Vladimir Shevchenko, Martin Valovič, Linda L. Vahala, George Vahala

Electrical & Computer Engineering Faculty Publications

The effect of the direction of the detected beam on the intensity of ECE is studied. It is found that the combined effects of the strong dependence of the conversion efficiencey of O mode at the plasma resonance on the direction of the incident wave and the partial screening of the beam waist by the MAST vessel wall, can be responsible for the weakening of ECE emission for some frequencies. The theoretical model for ECE data interpretation on MAST has been significantly improved. New features of the model are as follows: the quasioptical treatment of the receiving antenna, interference, polarization …

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Superfluorescence Polarization: Signature Of Collisional Redistribution, A. Kumarakrishnan, S. Chudasama, Xianming Han Jan 2003

Superfluorescence Polarization: Signature Of Collisional Redistribution, A. Kumarakrishnan, S. Chudasama, Xianming Han

Scholarship and Professional Work - LAS

We have studied effects of magnetic sublevel degeneracy on the polarization of superfluorescent pulses generated on the Ca 4s4p1P1–3d4s1D2 transition at 5.5μm. These pulses were generated from a cell of length 50 cm by optically pumping calcium vapor on the 4s21S0–4s4p1P1 transition in the presence of Ar gas. The axis of ellipticity of superfluorescence (SF) polarization is oriented parallel to the axis of the pump-laser polarization at large detunings, and undergoes an abrupt rotation through 90° for detunings close to resonance. The distribution of populations in the magnetic sublevels of the 1P1 state can be estimated using a simple model …

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Polarized Neutron Diffraction And Mössbauer Spectral Study Of Short-Range Magnetic Correlations In The Ferrimagnetic Layered Compounds (Pph₄) [FeIiFeIii(Ox)₃] And (Nbu₄) [FeIiFeIii(Ox)₃], Simon G. Carling, Dirk W. Visser, Dimitri Hautot, Ian D. Watts, Peter Day, Jürgen Ensling, Phillip Gütlich, Gary J. Long, Fernande Grandjean Sep 2002

Polarized Neutron Diffraction And Mössbauer Spectral Study Of Short-Range Magnetic Correlations In The Ferrimagnetic Layered Compounds (Pph₄) [FeIiFeIii(Ox)₃] And (Nbu₄) [FeIiFeIii(Ox)₃], Simon G. Carling, Dirk W. Visser, Dimitri Hautot, Ian D. Watts, Peter Day, Jürgen Ensling, Phillip Gütlich, Gary J. Long, Fernande Grandjean

Chemistry Faculty Research & Creative Works

Short-range antiferromagnetic correlations have been studied in the layered compounds (PPh4) [FeIIFeIII(ox)3] and (NBu4) [FeIIFeIII(ox)3] by neutron polarization analysis and Mössbauer spectroscopy. Polarized neutron diffraction profiles obtained between 2 and 50 K on (d20-Pph4) [FeIIFeIII(ox)3] show no magnetic Bragg scattering; the lack of such scattering indicates the absence of long-range magnetic order. However, a broad asymmetric feature observed at a Q of ca. 0.8 Å-1 is attributed to two-dimensional short-range magnetic correlations, which …

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Polarization Jet Events And Excitation Of Weak Sar Arcs, S. Sazykin, Bela G. Fejer, Y. I. Galperin, S. A. Grigoriev, L. V. Zinin, M. Mendillo Jun 2002

Polarization Jet Events And Excitation Of Weak Sar Arcs, S. Sazykin, Bela G. Fejer, Y. I. Galperin, S. A. Grigoriev, L. V. Zinin, M. Mendillo

Bela G. Fejer

[1] Polarization Jet (PJ), also known as Sub-Auroral Ion Drift (SAID), events are supersonic westward plasma drifts on the equatorward edge of the diffuse aurora in the evening and nighttime sector. Their optical F-region signatures are weak 630.0 nm red arcs colocated with regions of fast convection. These weak arcs resemble Stable Auroral Red (SAR) arcs observed during the recovery phase of magnetic storms, but have lower intensities, shorter lifetimes, and occur without a significant heat flux from the magnetosphere. Previous model studies underestimated the brightness of weak SAR arcs. We present calculations showing that ion-neutral collisional heating and ion …

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Effects Of Surface Morphology On The Anchoring And Electrooptical Dynamics Of Confined Nanoscale Liquid Crystalline Films, Alison Noble, Hye J. Kwon, Ralph G. Nuzzo Jan 2002

Effects Of Surface Morphology On The Anchoring And Electrooptical Dynamics Of Confined Nanoscale Liquid Crystalline Films, Alison Noble, Hye J. Kwon, Ralph G. Nuzzo

Educator Scholarship

The orientation and dynamics of two 40-nm thick films of 4-n-pentyl-4‘-cyanobiphenyl (5CB), a nematic liquid crystal, have been studied using step-scan Fourier transform infrared spectroscopy (FTIR). The films are confined in nanocavities bounded by an interdigitated electrode array (IDA) patterned on a zinc selenide (ZnSe) substrate. The effects of the ZnSe surface morphology (specifically, two variations of nanometer-scale corrugations obtained by mechanical polishing) on the initial ordering and reorientation dynamics of the electric-field-induced Freedericksz transition are presented here. The interaction of the 5CB with ZnSe surfaces bearing a spicular corrugation induces a homeotropic (surface normal) alignment of the …

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Mantle Deformation Beneath Southern Africa, Paul G. Silver, Stephen S. Gao, Kelly H. Liu, Kaapvaal Seismic Group Jul 2001

Mantle Deformation Beneath Southern Africa, Paul G. Silver, Stephen S. Gao, Kelly H. Liu, Kaapvaal Seismic Group

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Seismic anisotropy from the southern African mantle has been inferred from shear-wave splitting measured at 79 sites of the Southern African Seismic Experiment. These data provide the most dramatic support to date that Archean mantle deformation is preserved as fossil mantle anisotropy. Fast polarization directions systematically follow the trend of Archean structures and splitting delay times exhibit geologic control. The most anisotropic regions are Late-Archean in age (Zimbabwe craton, Limpopo belt, western Kaapvaal craton), with delay times reduced dramatically in off-craton regions to the southwest and Early-Archean regions to the southeast. While thin lithosphere can account for weak off-craton splitting, …

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Separation Of Recollision Mechanisms In Nonsequential Strong Field Double Ionization Of Ar: The Role Of Excitation Tunneling, Bernold Feuerstein, Daniel Fischer, Alexander Dorn, Claus Dieter Schroter, J. Deipenwisch, Jose R. Crespo Lopez-Urrutia, C. Hohr, Paul B. Neumayer, Horst Rottke, Christoph Trump, M. Wittmann, Georg Korn, Wolfgang Sandner, Robert Moshammer, Joachim Hermann Ullrich Jul 2001

Separation Of Recollision Mechanisms In Nonsequential Strong Field Double Ionization Of Ar: The Role Of Excitation Tunneling, Bernold Feuerstein, Daniel Fischer, Alexander Dorn, Claus Dieter Schroter, J. Deipenwisch, Jose R. Crespo Lopez-Urrutia, C. Hohr, Paul B. Neumayer, Horst Rottke, Christoph Trump, M. Wittmann, Georg Korn, Wolfgang Sandner, Robert Moshammer, Joachim Hermann Ullrich

Physics Faculty Research & Creative Works

Vector momentum distributions of two electrons created in double ionization of Ar by 25 fs, 0.25PW/cm2 laser pulses at 795 nm have been measured using a “reaction microscope.” At this intensity, where nonsequential ionization dominates, distinct correlation patterns are observed in the two-electron momentum distributions. A kinematical analysis of these spectra within the classical “recollision model” revealed an (e,2e)-like process and excitation with subsequent tunneling of the second electron as two different ionization mechanisms. This allows a qualitative separation of the two mechanisms demonstrating that excitation-tunneling is the dominant contribution to the total double ionization yield.

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G EP / G MP Ratio By Polarization Transfer In Ep→Ep, M. K. Jones, K. A. Aniol, F. T. Baker, J. Berthot, P. Y. Bertin, W. Bertozzi, A. Besson, L. Bimbot, W. U. Boeglin, E. J. Brash, D. Brown, J. R. Calarco, L. S. Cardman, C. C. Chang, J. P. Chen, E. Chudakov, S. Churchwell, E. Cisbani, D. S. Dale, R. De Leo, A. Deur, B. Diederich, J. J. Domingo, M. B. Epstein, L. A. Ewell, K. G. Fissum, A. Fleck, H. Fonvieille, S. Frullani, J. Gao, F. Garibaldi, A. Gasparian, G. Gerstner, S. Gilad, R. Gilman, A. Glamazdin, C. Glashausser, J. Gomez, V. Gorbenko, A. Green, J. O. Hansen, C. R. Howell, G. G. Kumbartzki, M. Kuss, Enkeleida K. Lakuriqi, G. Lavessiere, J. J. Lerose, M. Liang, R. A. Lindgren, N. Liyanage, G. J. Lolos, R. Macri, R. Madey, S. Malov, D. J. Margaziotis, P. Markowitz, K. Mccormick, J. I. Mcintyre, R. L. J. Van Der Meer, R. Michaels, B. D. Milbrath, J. Y. Mougey, S. K. Nanda, E. A. J. M. Offermann, Z. Papandreou, C. F. Perdrisat, G. G. Petratos, N. M. Piskunov, R. I. Pomatsalyuk, D. L. Prout, V. Punjabi, G. Quemener, R. D. Ransome, B. A. Raue, Y. Roblin, R. Roche, G. Rutledge, P. M. Rutt, A. Saha, T. Saito, A. J. Sarty, T. P. Smith, P. Sorokin, S. Strauch, R. Suleiman, K. Takahashi, J. A. Templon, L. Todor, P. E. Ulmer, G. M. Urciuoli, P. Vernin, B. Vlahovic, H. Voskanyan, K. Wijesooriya, B. B. Wojtsekhowski, R. J. Woo, F. Xiong, G. D. Zainea, Z. L. Zhou Feb 2000

G EP / G MP Ratio By Polarization Transfer In Ep→Ep, M. K. Jones, K. A. Aniol, F. T. Baker, J. Berthot, P. Y. Bertin, W. Bertozzi, A. Besson, L. Bimbot, W. U. Boeglin, E. J. Brash, D. Brown, J. R. Calarco, L. S. Cardman, C. C. Chang, J. P. Chen, E. Chudakov, S. Churchwell, E. Cisbani, D. S. Dale, R. De Leo, A. Deur, B. Diederich, J. J. Domingo, M. B. Epstein, L. A. Ewell, K. G. Fissum, A. Fleck, H. Fonvieille, S. Frullani, J. Gao, F. Garibaldi, A. Gasparian, G. Gerstner, S. Gilad, R. Gilman, A. Glamazdin, C. Glashausser, J. Gomez, V. Gorbenko, A. Green, J. O. Hansen, C. R. Howell, G. G. Kumbartzki, M. Kuss, Enkeleida K. Lakuriqi, G. Lavessiere, J. J. Lerose, M. Liang, R. A. Lindgren, N. Liyanage, G. J. Lolos, R. Macri, R. Madey, S. Malov, D. J. Margaziotis, P. Markowitz, K. Mccormick, J. I. Mcintyre, R. L. J. Van Der Meer, R. Michaels, B. D. Milbrath, J. Y. Mougey, S. K. Nanda, E. A. J. M. Offermann, Z. Papandreou, C. F. Perdrisat, G. G. Petratos, N. M. Piskunov, R. I. Pomatsalyuk, D. L. Prout, V. Punjabi, G. Quemener, R. D. Ransome, B. A. Raue, Y. Roblin, R. Roche, G. Rutledge, P. M. Rutt, A. Saha, T. Saito, A. J. Sarty, T. P. Smith, P. Sorokin, S. Strauch, R. Suleiman, K. Takahashi, J. A. Templon, L. Todor, P. E. Ulmer, G. M. Urciuoli, P. Vernin, B. Vlahovic, H. Voskanyan, K. Wijesooriya, B. B. Wojtsekhowski, R. J. Woo, F. Xiong, G. D. Zainea, Z. L. Zhou

Enkeleida K. Lakuriqi

The ratio of the proton's elastic electromagnetic form factors, G Ep / G Mp, was obtained by measuring Pt and Pl, the transverse and the longitudinal recoil proton polarization, respectively. For elastic ep→ep, G Ep / G Mp is proportional to Pt / Pl. Simultaneous measurement of Pt and Pl in a polarimeter provides good control of the systematic uncertainty. The results for the ratio G Ep / G Mp show a systematic decrease as Q2 increases from 0.5 to 3.5GeV2, indicating for the first time a definite difference in the spatial distribution of charge …

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Photoabsorption Spectra Of Argon Cation Clusters: Monte Carlo Simulations Using Many-Body Polarization, Jose A. Gascon, Randall W. Hall Jan 2000

Photoabsorption Spectra Of Argon Cation Clusters: Monte Carlo Simulations Using Many-Body Polarization, Jose A. Gascon, Randall W. Hall

Collected Faculty and Staff Scholarship

A simple, semiempirical model that includes many-body polarization is used to study the ground and excited stateproperties of Ar+N clusters (N=3–23) at 80 K. For purposes of comparison, a model that does not include many-body polarization is used to study clusters with N=3–27.Monte Carlo simulations are used to calculate the average properties of these clusters. The model is similar to one previously used to study argon cation clusters without many-body polarization. The photoabsorptionspectrum is in good agreement with experiment; in particular, the photoabsorptionspectra for cluster sizes 4–10 do not show the blueshift that is seen with models that do not …

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Renormalons As Dilation Modes In The Functional Space, A. Babansky, I. Balitsky Jan 2000

Renormalons As Dilation Modes In The Functional Space, A. Babansky, I. Balitsky

Physics Faculty Publications

There are two possible sources of the factorial large-order behavior of a typical perturbative series. First, the number of different Feynman diagrams may be large; second, there may be abnormally large diagrams known as renormalons. It is well known that the large combinatorial number of diagrams is described by instanton-type solutions of the classical equations. We demonstrate that, from the functional-integral viewpoint, the renormalons do not correspond to a particular configuration but manifest themselves as dilatation modes in the functional space.

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Studies On Methods Of Fuel Cells Electrodes Preparation, Jun Gu, Sheng Sui, Guangqiang Li, Zhitong Sui Nov 1999

Studies On Methods Of Fuel Cells Electrodes Preparation, Jun Gu, Sheng Sui, Guangqiang Li, Zhitong Sui

Journal of Electrochemistry

In fuel cells,the structure of electrodes is an important factor which effect the cell performance.To improve the structure and the performance of electrodes,a new method of providing fuel cell electrodes is proposed in this paper.PTFE(polytetrafluoroethylene) and ethyne black was ground for about half an hour in a high_speed grinder,then the catalyst was added into the grinder and milled for an hour.This milled catalyst was transferred into a mixer followed by the addition of surface_active agent. After a suspension was formed,it was filtered under vacuum condition.Then a thin uniform filter_cake of the catalyst was formed,which was rolled together with a current_collecting …

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Polarization Of Astronomical Maser Radiation. Iv. Circular Polarization Profiles, Moshe Elitzur Sep 1998

Polarization Of Astronomical Maser Radiation. Iv. Circular Polarization Profiles, Moshe Elitzur

Physics and Astronomy Faculty Publications

Profile comparison of the Stokes parameters V and I is a powerful tool for maser data analysis, which provides the first direct methods for unambiguous determination of (1) the maser saturation stage, (2) the amplification optical depth and intrinsic Doppler width of unsaturated masers, and (3) the comparative magnitudes of Zeeman splitting and Doppler line width. Circular polarization recently detected in OH 1720 MHz emission from the Galactic center appears to provide the first direct evidence for maser saturation.

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S K S Splitting Beneath Continental Rift Zones, Stephen S. Gao, Paul M. Davis, Kelly H. Liu, Philip D. Slack, Andrew W. Rigor, Yu A. Zorin, Valentina V. Mordvinova, Vladimir M. Kozhevnikov, Nikolai A. Logatchev Oct 1997

S K S Splitting Beneath Continental Rift Zones, Stephen S. Gao, Paul M. Davis, Kelly H. Liu, Philip D. Slack, Andrew W. Rigor, Yu A. Zorin, Valentina V. Mordvinova, Vladimir M. Kozhevnikov, Nikolai A. Logatchev

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

We present measurements of S K S splitting at 28 digital seismic stations and 35 analog stations in the Baikal rift zone, Siberia, and adjacent areas, and at 17 stations in the East African Rift in Kenya and compare them with previous measurements from the Rio Grande Rift of North America. Fast directions in the inner region of the Baikal rift zone are distributed in two orthogonal directions, NE and NW, approximately parallel and perpendicular to the NE strike of the rift. In the adjacent Siberian platform and northern Mongolian fold belt, only the rift-orthogonal fast direction is observed. In …

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Electrochemical Study Of The Corrosion Behavior Of Coalesced Copper And Sw-206 Stainless Steel In The Acetic-Acid Solution, Rongzong Hu, Changjian Lin, Jianguang Tan Aug 1996

Electrochemical Study Of The Corrosion Behavior Of Coalesced Copper And Sw-206 Stainless Steel In The Acetic-Acid Solution, Rongzong Hu, Changjian Lin, Jianguang Tan

Journal of Electrochemistry

In order to provide a theoretic and experimental consideration for the material selection and anit-corrosion in the petrochemical industries the corrosion behavior of coalesced copper and sw-206 stainless steel in the acetic acid solution was studied by electrochemical impedance spectroscopy and polarization techniques. The effects of the temperature,acetic acid concentration and solubilized oxygen in the acetic acid solution on the corrosion process of this two metals were analyzed. It was found that these effects obviously accelerate corrosion process for the coalesced copper,but no apparent influnce for the sw-206 stainless steel.In the the acetic acid solution,containing water and oxygen were beneficial …

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Limits To Cosmic Background Radiation Fluctuations At 8.44 Ghz Between Angular Scales 10″ And 200″, Edward B. Fomalont, R. Bruce Partridge, James D. Lowenthal, Rogier A. Windhorst Feb 1993

Limits To Cosmic Background Radiation Fluctuations At 8.44 Ghz Between Angular Scales 10″ And 200″, Edward B. Fomalont, R. Bruce Partridge, James D. Lowenthal, Rogier A. Windhorst

Astronomy: Faculty Publications

We have used the VLA at 8.44 GHz to measure fluctuations in the cosmic background radiation (CBR) from two deep images, each 7′ x 7′ in size. No fluctuations between the angular scales 10″ and 200″ were detected. The most accurate limit (95% confidence) is ΔT/TCBR < 1.9 x 10-5 for 80″ resolution. For random Gaussian fluctuations with coherence angle θc, the limits are ΔT/TCBR < 30 x 10-5 for 22″ < θc < 60″. Outside this range the limits increase to ΔT/TCBR < 5 x 10-5 at θc = 12″ or 100″ and ΔT/TCBR < 10 x 10-5 at θc = 5″ or 120″. Similar limits have been obtained for the circularly and linearly polarized components of the CBR fluctuations. These limits were derived from the residual fluctuations in the images after (1) removing brighter foreground sources (> 14.5 μJy) which covered about 10% of each image; (2) estimating fluctuations of weaker sources by extrapolating the count of dN/dS = 4.6S-2.3 Jy-1 sr-1 to 4 μJy; and (3) determining fluctuations from receiver noise and instrumental errors by comparing the image variances from two independent halves of the data set. All analysis was …

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The R Aquarii System At Optical And Radio Wavelengths, J. M. Hollis, Menas Kafatos, A. G. Michalitsianos, H. A. Mcalister Jan 1985

The R Aquarii System At Optical And Radio Wavelengths, J. M. Hollis, Menas Kafatos, A. G. Michalitsianos, H. A. Mcalister

Mathematics, Physics, and Computer Science Faculty Articles and Research

Observations of the symbiotic binary R Aquarii environment were obtained with the Very Large Array (VLA) at 2, 6, and 20 em at the same epoch. The observed spectral index and strong linear polarization reveal that emission from the compact double radio source discovered in previous observations is nonthermal; thus, this source is not associated with R Aquarii but is an extragalactic background object. The spectral index of the compact nebula surrounding R Aquarii indicates that the emission is thermal and the nebula is ionized by an unseen, hot companion to the Mira-like variable R Aquarii. As expected, this region …

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Xanes In (Tmtsef)2re04: Polarization Dependence Of The Se K-Edge, Juana Vivó Acrivos, S.S. P. Parkin Jan 1983

Xanes In (Tmtsef)2re04: Polarization Dependence Of The Se K-Edge, Juana Vivó Acrivos, S.S. P. Parkin

Faculty Publications, Chemistry

We have measured XANES (X-ray Absorption Near Edge Spectra) near the Re Li (i=l,II,III) edges in (TMTTF)2Re04 and (TMTSeF) 2Re04 and the Se K edge in the latter compound. An important dependence of the XANES at the Se K edge on the polarisation of the incident beam with respect to the crystal axes was observed, whose interpretation can give information on the symmetry of the unoccupied conduction band states. The positions of the Re L edges were compared with those in several inorganic compounds containing Re in various oxidation states, and were found to be, within experimental error, the same …

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Xanes In (Tmtsef)2re04: Polarization Dependence Of The Se K-Edge, Juana Vivó Acrivos, S.S. P. Parkin Jan 1983

Xanes In (Tmtsef)2re04: Polarization Dependence Of The Se K-Edge, Juana Vivó Acrivos, S.S. P. Parkin

Juana Vivó Acrivos

We have measured XANES (X-ray Absorption Near Edge Spectra) near the Re Li (i=l,II,III) edges in (TMTTF)2Re04 and (TMTSeF) 2Re04 and the Se K edge in the latter compound. An important dependence of the XANES at the Se K edge on the polarisation of the incident beam with respect to the crystal axes was observed, whose interpretation can give information on the symmetry of the unoccupied conduction band states. The positions of the Re L edges were compared with those in several inorganic compounds containing Re in various oxidation states, and were found to be, within experimental error, the same …

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Hydrogen Overvoltage Of Cadmium Bismuth And Antimony Bismuth Alloys, Edwin W. Stevens Oct 1944

Hydrogen Overvoltage Of Cadmium Bismuth And Antimony Bismuth Alloys, Edwin W. Stevens

Bachelors Theses and Reports, 1928 - 1970

A method to measure hydrogen overvoltage was devel­oped and checked with metals of known overvoltage. Alloys of bismuth and antimony and of bismuth and cad­mium were prepared and their overvoltages determined.

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The Electret - An Effort To Find The Cause Of Its Permanent Polarization, Ernest F. Lundeen Jan 1932

The Electret - An Effort To Find The Cause Of Its Permanent Polarization, Ernest F. Lundeen

University of the Pacific Theses and Dissertations

Certain waxes when solidified in a strong electric field exhibit unusual electrical properties. Several days after formation there is a polarization in the direction of the field which seems to persist for an indefinite length of time. The surface that was in contact with the anode during formation first ass a negative charge and then obtains a positive charge, which under proper conditions is practically permanent. The surface that was in contact with the cathode first has a positive charge and then obtains a negative charge which is the permanent charge.

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