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Galeaclolusite, [Al6(AsO4)3(OH)9(H2O)4]⋅8H2O, a new bulachite-related mineral from Cap Garonne, France
- Ian E. Grey, George Favreau, Stuart J. Mills, W. Gus Mumme, Catherine Bougerol, Helen E.A. Brand, Anthony R. Kampf, Colin M. MacRae, Finlay Shanks
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- Journal:
- Mineralogical Magazine / Volume 85 / Issue 2 / April 2021
- Published online by Cambridge University Press:
- 04 December 2020, pp. 142-148
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Galeaclolusite, [Al6(AsO4)3(OH)9(H2O)4]⋅8H2O, is a new secondary hydrated aluminium arsenate mineral from Cap Garonne, Var, France. It forms crusts and spheroids of white fibres up to 50 μm long by 0.4 μm wide and only 0.1 μm thick. The fibres are elongated along [001] and flattened on (100). The calculated density is 2.27 g⋅cm–3. Optically, galeaclolusite is biaxial with α = 1.550(5), β not determined, γ = 1.570(5) (white light) and partial orientation: Z = c (fibre axis). Electron microprobe analyses coupled with crystal structure refinement results gives an empirical formula based on 33 O atoms of Al5.72Si0.08As2.88O33H34.12. Galeaclolusite is orthorhombic, Pnma, with a = 19.855(4), b = 17.6933(11), c = 7.7799(5) Å, V = 2733.0(7) Å3 and Z = 4. The crystal structure of galeaclolusite was established from its close relationship to bulachite and refined using synchrotron powder X-ray diffraction data. It is based on heteropolyhedral layers, parallel to (100), of composition Al6(AsO4)3(OH)9(H2O)4 and with H-bonded H2O between the layers. The layers contain [001] spiral chains of edge-shared octahedra, decorated with corner-connected AsO4 tetrahedra, that are the same as in the mineral liskeardite.
Bulachite, [Al6(AsO4)3(OH)9(H2O)4]⋅2H2O from Cap Garonne, France: Crystal structure and formation from a higher hydrate
- Ian E. Grey, Emre Yoruk, Stéphanie Kodjikian, Holger Klein, Catherine Bougerol, Helen E.A. Brand, Pierre Bordet, William G. Mumme, Georges Favreau, Stuart J. Mills
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- Journal:
- Mineralogical Magazine / Volume 84 / Issue 4 / August 2020
- Published online by Cambridge University Press:
- 30 June 2020, pp. 608-615
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Bulachite specimens from Cap Garonne, France, comprise two intimately mixed hydrated aluminium arsenate minerals with the same Al:As ratio of 2:1 and with different water contents. The crystal structures of both minerals have been solved using data from low-dose electron diffraction tomography combined with synchrotron powder X-ray diffraction. One of the minerals has the same powder X-ray diffraction pattern (PXRD) as for published bulachite. It has orthorhombic symmetry, space group Pnma with unit-cell parameters a = 15.3994(3), b = 17.6598(3), c = 7.8083(1) Å and Z = 4, with the formula [Al6(AsO4)3(OH)9(H2O)4]⋅2H2O. The second mineral is a higher hydrate with composition [Al6(AsO4)3(OH)9(H2O)4]⋅8H2O. It has the same Pnma space group and unit-cell parameters a = 19.855(4), b = 17.6933(11) and c = 7.7799(5) Å i.e. almost the same b and c parameters but a much larger a parameter. The structures are based on polyhedral layers, parallel to (100), of composition [Al6(AsO4)3(OH)9(H2O)4] and with H-bonded H2O between the layers. The layers contain [001] spiral chains of edge-shared octahedra, decorated with corner connected AsO4 tetrahedra that are the same as in the mineral liskeardite. The spiral chains are joined together by octahedral edge-sharing to form layers parallel to (100). Synchrotron PXRD patterns collected at different temperatures during heating of the specimen show that the higher-hydrate mineral starts transforming to bulachite when heated to 50°C, and the transformation is complete between 75 and 100°C.
The 1872 Introduction to Hovedstr⊘mninger i det 19de Aarhundredes Litteratur (Main Currents of Nineteenth-Century Literature)
- Georg Brandes, Lynn R. Wilkinson
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- Journal:
- PMLA / Publications of the Modern Language Association of America / Volume 132 / Issue 3 / May 2017
- Published online by Cambridge University Press:
- 23 October 2020, pp. 696-705
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- May 2017
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From Comparative Literature to Cultural Renewal: Georg Brandes's 1872 Introduction to Main Currents of Nineteenth-Century Literature
“The only literature that is alive today is one that provokes debate.” These words ring out in the first published version of a lecture Georg Brandes gave at the University of Copenhagen on 3 November 1871. The lecture was the introduction to a series that changed the course not only of his life but also of Scandinavian and European cultural history. Born in Copenhagen in 1842 to assimilated Jewish parents, Brandes had recently completed a dissertation on French aesthetics and literary criticism and hoped that his lecture series would allow him to replace Carsten Hauch as professor of aesthetics at the university. Brilliant and iconoclastic, the lectures also responded to the Danish defeat in the 1864 war with Prussia, portraying Danish literature and culture as morbidly inward and insular. Brandes urged his countrymen to look abroad, to traditions such as the French, whose literature included many notable writers who grappled with social and political issues, especially those who came of age during the revolutions of 1789 and 1830.
Contributors
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- By Mitchell Aboulafia, Frederick Adams, Marilyn McCord Adams, Robert M. Adams, Laird Addis, James W. Allard, David Allison, William P. Alston, Karl Ameriks, C. Anthony Anderson, David Leech Anderson, Lanier Anderson, Roger Ariew, David Armstrong, Denis G. Arnold, E. J. Ashworth, Margaret Atherton, Robin Attfield, Bruce Aune, Edward Wilson Averill, Jody Azzouni, Kent Bach, Andrew Bailey, Lynne Rudder Baker, Thomas R. Baldwin, Jon Barwise, George Bealer, William Bechtel, Lawrence C. Becker, Mark A. Bedau, Ernst Behler, José A. Benardete, Ermanno Bencivenga, Jan Berg, Michael Bergmann, Robert L. Bernasconi, Sven Bernecker, Bernard Berofsky, Rod Bertolet, Charles J. Beyer, Christian Beyer, Joseph Bien, Joseph Bien, Peg Birmingham, Ivan Boh, James Bohman, Daniel Bonevac, Laurence BonJour, William J. Bouwsma, Raymond D. Bradley, Myles Brand, Richard B. Brandt, Michael E. Bratman, Stephen E. Braude, Daniel Breazeale, Angela Breitenbach, Jason Bridges, David O. Brink, Gordon G. Brittan, Justin Broackes, Dan W. Brock, Aaron Bronfman, Jeffrey E. Brower, Bartosz Brozek, Anthony Brueckner, Jeffrey Bub, Lara Buchak, Otavio Bueno, Ann E. Bumpus, Robert W. Burch, John Burgess, Arthur W. Burks, Panayot Butchvarov, Robert E. Butts, Marina Bykova, Patrick Byrne, David Carr, Noël Carroll, Edward S. Casey, Victor Caston, Victor Caston, Albert Casullo, Robert L. Causey, Alan K. L. Chan, Ruth Chang, Deen K. Chatterjee, Andrew Chignell, Roderick M. Chisholm, Kelly J. Clark, E. J. Coffman, Robin Collins, Brian P. Copenhaver, John Corcoran, John Cottingham, Roger Crisp, Frederick J. Crosson, Antonio S. Cua, Phillip D. Cummins, Martin Curd, Adam Cureton, Andrew Cutrofello, Stephen Darwall, Paul Sheldon Davies, Wayne A. Davis, Timothy Joseph Day, Claudio de Almeida, Mario De Caro, Mario De Caro, John Deigh, C. F. Delaney, Daniel C. Dennett, Michael R. DePaul, Michael Detlefsen, Daniel Trent Devereux, Philip E. Devine, John M. Dillon, Martin C. Dillon, Robert DiSalle, Mary Domski, Alan Donagan, Paul Draper, Fred Dretske, Mircea Dumitru, Wilhelm Dupré, Gerald Dworkin, John Earman, Ellery Eells, Catherine Z. Elgin, Berent Enç, Ronald P. Endicott, Edward Erwin, John Etchemendy, C. Stephen Evans, Susan L. Feagin, Solomon Feferman, Richard Feldman, Arthur Fine, Maurice A. Finocchiaro, William FitzPatrick, Richard E. Flathman, Gvozden Flego, Richard Foley, Graeme Forbes, Rainer Forst, Malcolm R. Forster, Daniel Fouke, Patrick Francken, Samuel Freeman, Elizabeth Fricker, Miranda Fricker, Michael Friedman, Michael Fuerstein, Richard A. Fumerton, Alan Gabbey, Pieranna Garavaso, Daniel Garber, Jorge L. A. Garcia, Robert K. Garcia, Don Garrett, Philip Gasper, Gerald Gaus, Berys Gaut, Bernard Gert, Roger F. Gibson, Cody Gilmore, Carl Ginet, Alan H. Goldman, Alvin I. Goldman, Alfonso Gömez-Lobo, Lenn E. Goodman, Robert M. Gordon, Stefan Gosepath, Jorge J. E. Gracia, Daniel W. Graham, George A. Graham, Peter J. Graham, Richard E. Grandy, I. Grattan-Guinness, John Greco, Philip T. Grier, Nicholas Griffin, Nicholas Griffin, David A. Griffiths, Paul J. Griffiths, Stephen R. Grimm, Charles L. Griswold, Charles B. Guignon, Pete A. Y. Gunter, Dimitri Gutas, Gary Gutting, Paul Guyer, Kwame Gyekye, Oscar A. Haac, Raul Hakli, Raul Hakli, Michael Hallett, Edward C. Halper, Jean Hampton, R. James Hankinson, K. R. Hanley, Russell Hardin, Robert M. Harnish, William Harper, David Harrah, Kevin Hart, Ali Hasan, William Hasker, John Haugeland, Roger Hausheer, William Heald, Peter Heath, Richard Heck, John F. Heil, Vincent F. Hendricks, Stephen Hetherington, Francis Heylighen, Kathleen Marie Higgins, Risto Hilpinen, Harold T. Hodes, Joshua Hoffman, Alan Holland, Robert L. Holmes, Richard Holton, Brad W. Hooker, Terence E. Horgan, Tamara Horowitz, Paul Horwich, Vittorio Hösle, Paul Hoβfeld, Daniel Howard-Snyder, Frances Howard-Snyder, Anne Hudson, Deal W. Hudson, Carl A. Huffman, David L. Hull, Patricia Huntington, Thomas Hurka, Paul Hurley, Rosalind Hursthouse, Guillermo Hurtado, Ronald E. Hustwit, Sarah Hutton, Jonathan Jenkins Ichikawa, Harry A. Ide, David Ingram, Philip J. Ivanhoe, Alfred L. Ivry, Frank Jackson, Dale Jacquette, Joseph Jedwab, Richard Jeffrey, David Alan Johnson, Edward Johnson, Mark D. Jordan, Richard Joyce, Hwa Yol Jung, Robert Hillary Kane, Tomis Kapitan, Jacquelyn Ann K. Kegley, James A. Keller, Ralph Kennedy, Sergei Khoruzhii, Jaegwon Kim, Yersu Kim, Nathan L. King, Patricia Kitcher, Peter D. Klein, E. D. Klemke, Virginia Klenk, George L. Kline, Christian Klotz, Simo Knuuttila, Joseph J. Kockelmans, Konstantin Kolenda, Sebastian Tomasz Kołodziejczyk, Isaac Kramnick, Richard Kraut, Fred Kroon, Manfred Kuehn, Steven T. Kuhn, Henry E. Kyburg, John Lachs, Jennifer Lackey, Stephen E. Lahey, Andrea Lavazza, Thomas H. Leahey, Joo Heung Lee, Keith Lehrer, Dorothy Leland, Noah M. Lemos, Ernest LePore, Sarah-Jane Leslie, Isaac Levi, Andrew Levine, Alan E. Lewis, Daniel E. Little, Shu-hsien Liu, Shu-hsien Liu, Alan K. L. Chan, Brian Loar, Lawrence B. Lombard, John Longeway, Dominic McIver Lopes, Michael J. Loux, E. J. Lowe, Steven Luper, Eugene C. Luschei, William G. Lycan, David Lyons, David Macarthur, Danielle Macbeth, Scott MacDonald, Jacob L. Mackey, Louis H. Mackey, Penelope Mackie, Edward H. Madden, Penelope Maddy, G. B. Madison, Bernd Magnus, Pekka Mäkelä, Rudolf A. Makkreel, David Manley, William E. Mann (W.E.M.), Vladimir Marchenkov, Peter Markie, Jean-Pierre Marquis, Ausonio Marras, Mike W. Martin, A. P. Martinich, William L. McBride, David McCabe, Storrs McCall, Hugh J. McCann, Robert N. McCauley, John J. McDermott, Sarah McGrath, Ralph McInerny, Daniel J. McKaughan, Thomas McKay, Michael McKinsey, Brian P. McLaughlin, Ernan McMullin, Anthonie Meijers, Jack W. Meiland, William Jason Melanson, Alfred R. Mele, Joseph R. Mendola, Christopher Menzel, Michael J. Meyer, Christian B. Miller, David W. Miller, Peter Millican, Robert N. Minor, Phillip Mitsis, James A. Montmarquet, Michael S. Moore, Tim Moore, Benjamin Morison, Donald R. Morrison, Stephen J. Morse, Paul K. Moser, Alexander P. D. Mourelatos, Ian Mueller, James Bernard Murphy, Mark C. Murphy, Steven Nadler, Jan Narveson, Alan Nelson, Jerome Neu, Samuel Newlands, Kai Nielsen, Ilkka Niiniluoto, Carlos G. Noreña, Calvin G. Normore, David Fate Norton, Nikolaj Nottelmann, Donald Nute, David S. Oderberg, Steve Odin, Michael O’Rourke, Willard G. Oxtoby, Heinz Paetzold, George S. Pappas, Anthony J. Parel, Lydia Patton, R. P. Peerenboom, Francis Jeffry Pelletier, Adriaan T. Peperzak, Derk Pereboom, Jaroslav Peregrin, Glen Pettigrove, Philip Pettit, Edmund L. Pincoffs, Andrew Pinsent, Robert B. Pippin, Alvin Plantinga, Louis P. Pojman, Richard H. Popkin, John F. Post, Carl J. Posy, William J. Prior, Richard Purtill, Michael Quante, Philip L. Quinn, Philip L. Quinn, Elizabeth S. Radcliffe, Diana Raffman, Gerard Raulet, Stephen L. Read, Andrews Reath, Andrew Reisner, Nicholas Rescher, Henry S. Richardson, Robert C. Richardson, Thomas Ricketts, Wayne D. Riggs, Mark Roberts, Robert C. Roberts, Luke Robinson, Alexander Rosenberg, Gary Rosenkranz, Bernice Glatzer Rosenthal, Adina L. Roskies, William L. Rowe, T. M. Rudavsky, Michael Ruse, Bruce Russell, Lilly-Marlene Russow, Dan Ryder, R. M. Sainsbury, Joseph Salerno, Nathan Salmon, Wesley C. Salmon, Constantine Sandis, David H. Sanford, Marco Santambrogio, David Sapire, Ruth A. Saunders, Geoffrey Sayre-McCord, Charles Sayward, James P. Scanlan, Richard Schacht, Tamar Schapiro, Frederick F. Schmitt, Jerome B. Schneewind, Calvin O. Schrag, Alan D. Schrift, George F. Schumm, Jean-Loup Seban, David N. Sedley, Kenneth Seeskin, Krister Segerberg, Charlene Haddock Seigfried, Dennis M. Senchuk, James F. Sennett, William Lad Sessions, Stewart Shapiro, Tommie Shelby, Donald W. Sherburne, Christopher Shields, Roger A. Shiner, Sydney Shoemaker, Robert K. Shope, Kwong-loi Shun, Wilfried Sieg, A. John Simmons, Robert L. Simon, Marcus G. Singer, Georgette Sinkler, Walter Sinnott-Armstrong, Matti T. Sintonen, Lawrence Sklar, Brian Skyrms, Robert C. Sleigh, Michael Anthony Slote, Hans Sluga, Barry Smith, Michael Smith, Robin Smith, Robert Sokolowski, Robert C. Solomon, Marta Soniewicka, Philip Soper, Ernest Sosa, Nicholas Southwood, Paul Vincent Spade, T. L. S. Sprigge, Eric O. Springsted, George J. Stack, Rebecca Stangl, Jason Stanley, Florian Steinberger, Sören Stenlund, Christopher Stephens, James P. Sterba, Josef Stern, Matthias Steup, M. A. Stewart, Leopold Stubenberg, Edith Dudley Sulla, Frederick Suppe, Jere Paul Surber, David George Sussman, Sigrún Svavarsdóttir, Zeno G. Swijtink, Richard Swinburne, Charles C. Taliaferro, Robert B. Talisse, John Tasioulas, Paul Teller, Larry S. Temkin, Mark Textor, H. S. Thayer, Peter Thielke, Alan Thomas, Amie L. Thomasson, Katherine Thomson-Jones, Joshua C. Thurow, Vzalerie Tiberius, Terrence N. Tice, Paul Tidman, Mark C. Timmons, William Tolhurst, James E. Tomberlin, Rosemarie Tong, Lawrence Torcello, Kelly Trogdon, J. D. Trout, Robert E. Tully, Raimo Tuomela, John Turri, Martin M. Tweedale, Thomas Uebel, Jennifer Uleman, James Van Cleve, Harry van der Linden, Peter van Inwagen, Bryan W. Van Norden, René van Woudenberg, Donald Phillip Verene, Samantha Vice, Thomas Vinci, Donald Wayne Viney, Barbara Von Eckardt, Peter B. M. Vranas, Steven J. Wagner, William J. Wainwright, Paul E. Walker, Robert E. Wall, Craig Walton, Douglas Walton, Eric Watkins, Richard A. Watson, Michael V. Wedin, Rudolph H. Weingartner, Paul Weirich, Paul J. Weithman, Carl Wellman, Howard Wettstein, Samuel C. Wheeler, Stephen A. White, Jennifer Whiting, Edward R. Wierenga, Michael Williams, Fred Wilson, W. Kent Wilson, Kenneth P. Winkler, John F. Wippel, Jan Woleński, Allan B. Wolter, Nicholas P. Wolterstorff, Rega Wood, W. Jay Wood, Paul Woodruff, Alison Wylie, Gideon Yaffe, Takashi Yagisawa, Yutaka Yamamoto, Keith E. Yandell, Xiaomei Yang, Dean Zimmerman, Günter Zoller, Catherine Zuckert, Michael Zuckert, Jack A. Zupko (J.A.Z.)
- Edited by Robert Audi, University of Notre Dame, Indiana
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- The Cambridge Dictionary of Philosophy
- Published online:
- 05 August 2015
- Print publication:
- 27 April 2015, pp ix-xxx
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Two Aircraft Carriers’ Perspectives: A Comparative of Control Measures in Shipboard H1N1 Outbreaks
- Jared L. Harwood, Joseph T. LaVan, George J. Brand II
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- Journal:
- Disaster Medicine and Public Health Preparedness / Volume 7 / Issue 1 / February 2013
- Published online by Cambridge University Press:
- 25 April 2013, pp. 29-35
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Background
The USS George Washington (GW) and the USS Ronald Reagan (RR), 2 US Navy aircraft carriers, experienced almost simultaneous outbreaks of novel H1N1 influenza A in the summer of 2009. We compared the respective epidemic control measures taken and subsequent lessons learned.
MethodsData were collated from both outbreaks to assess various elements including attack rate, isolation/quarantine protocols, and treatment methods. The respective duration of each outbreak was compared with survival curve analysis. The number of personnel affected in each outbreak was compared using χ2 analysis.
ResultsDifferences were found in the protocols used on the 2 ships. The GW treated about two-thirds of the patients with oseltamivir through day 14 and quarantined all patients meeting case definition throughout the outbreak. Face masks were used throughout. The RR used oseltamivir and quarantined many fewer patients (through days 5 and 3, respectively). No face masks were used after day 5. The outbreaks were similar in duration (GW = 25 days, RR = 27 days, P = .38), but the RR had significantly more cases (n = 253 vs 142, P < .0001). A portion of each group had samples that were confirmed H1N1 by polymerase chain reaction.
ConclusionsGW's protocol, including aggressive oseltamivir treatment of two-thirds of the cases and quarantine throughout the duration decreased the overall number of personnel affected, likely reducing the overall control reproduction number. Both outbreaks were similar in duration. Even though the GW expended significantly more resources than the RR, if the 2009 pandemic H1N1 strain had been as clinically severe as the 1918 pandemic, a more stringent treatment protocol may have been the only way to prevent significant operational impact.(Disaster Med Public Health Preparedness. 2013;7:29-35)
The Attack Rate of H1N1 in Various Berthing Configurations On Board an Aircraft Carrier
- Jared L. Harwood, Joseph T. LaVan, George J. Brand II
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- Journal:
- Disaster Medicine and Public Health Preparedness / Volume 7 / Issue 2 / April 2013
- Published online by Cambridge University Press:
- 04 April 2013, pp. 131-135
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Objective
We compared attack rates for novel H1N1 influenza A (H1N1) among various groups aboard an aircraft carrier as influenced by characteristics of their living arrangements.
MethodsDuring an outbreak of H1N1 on board the USS George Washington (GW), group affiliation (department or squadron membership) data were obtained on all patients who were placed in respiratory isolation based on their diagnosis with presumptive H1N1. Because berthing spaces are assigned by department and various characteristics of each department's berthing spaces are known, analysis of attack rates in comparison to these characteristics was possible. Attack rates were compared with the square feet of living space per sailor, occupancy rate of the berthing areas, and size of the berthing areas. These results were further correlated with the mission of the various departments or squadrons.
ResultsThe average attack rate was 3%, with the highest rates occurring in departments or squadrons whose mission required ongoing contact with civilian populations ashore. The attack rate among officers was 2.04 versus 3.19 among enlisted personnel; this difference was not significant (P = .21). The attack rate for women was 1.90 versus 3.09 for men, which was significant (P = .05). Although attack rates varied considerably based on organizational mission, no correlation was found between attack rate and square feet of living space per person or occupancy rate or size of berthing spaces.
ConclusionsThe attack rate of the outbreak overall was limited to 3%. Smaller and more crowded berthing configurations did not contribute to higher attack rates, suggesting that transmission occurs most frequently elsewhere while engaged in other activities such as working, eating, or relaxing. Further studies are necessary to filter out potential correlations or variables not identified in this study, such as the difference between the number of men and women isolated. (Disaster Med Public Health Preparedness. 2012;0:1-5)
Background Impurity Reduction and Iron Doping of Gallium Nitride Wafers
- Robert P. Vaudo, Xueping Xu, Allan D. Salant, Joseph A. Malcarne, Edward L. Hutchins, George R. Brandes
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- Journal:
- MRS Online Proceedings Library Archive / Volume 743 / 2002
- Published online by Cambridge University Press:
- 11 February 2011, L3.37
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- 2002
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Background impurities and the resulting electrical characteristics were studied for GaN wafers grown using hydride vapor phase epitaxy at various growth conditions. The electron concentration was found to decrease with increasing GaN thickness, by orders of magnitude in the first few microns of growth, but continuing gradually for thousands of microns. Physical removal of the backside degenerate layer enabled improved analysis of the electrical properties. Secondary ion mass spectroscopy was used to determine that the presence of oxygen and silicon accounted for the electron concentration for unintentionally n-type doped material. The concentration of oxygen was found to vary more than that of silicon and increased with decreasing growth temperature. The resistivity was measured to be as high as 1 ohm-cm, corresponding to a carrier concentration of 1016 cm−3. Iron was demonstrated to effectively compensate the residual donors and increased the resistivity to greater than 109 ohm-cm at room temperature and greater than 3×105 ohm-cm at 250 °C. An activation energy for the iron-doped GaN was determined by variable temperature resistivity measurements to be 0.51 eV.
Properties of Delta Doped Al0.25Ga0.75N and GaN Epitaxial Layers
- Jeffrey S. Flynn, Leah G. Wallace, Joe A. Dion, Edward L. Hutchins, Helder Antunes, George R. Brandes
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- Journal:
- MRS Online Proceedings Library Archive / Volume 743 / 2002
- Published online by Cambridge University Press:
- 11 February 2011, L11.44
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- 2002
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Delta doping (paused growth doping) was investigated as an alternative to uniformly distributing the dopant in the nitride semiconductor layer. In this work, delta doped layers were produced in MOVPE-grown AlGaN and GaN layers at a susceptor temperature of 1220°C by turning off the group III precursors (TMG and TMA) and introducing into the reactor a silicon precursor Si2H6 (disilane) for a fixed period (pause time) before growth was restarted. The compositional and electrical properties as a function of aluminum content and dopant flux were investigated for nitride layers on 2 inch c-plane sapphire substrates. Secondary ion mass spectroscopy (SIMS) measurements revealed a sharp silicon peak with a FWHM of 5.7 ± 0.6 nm for an Al0.25Ga0.75N sample and 10.0 ± 0.6 nm for a GaN sample with sheet charges of 7.9×1012 cm−2 and 9.9×1012 cm−2,respectively. Room temperature Hall mobility as high as 265 cm2 V−1s−1 for a sheet charge 7.9×1012 cm−2 was demonstrated for delta doped Al0.25Ga0.75N layers, but the mobility enhancement saturated and then decreased with increasing sheet charge. Room temperature sheet charge increased with increasing dopant flux for delta-doped AlGaN and GaN layers. Sheet charge density as high as 2.2×1013 cm−2 and 1.3×1013 cm−2 was measured at room temperature for Al0.25Ga0.75N and GaN delta doped layers, respectively. Under identical doping conditions, the Hall sheet charge of the delta doped Al0.25Ga0.75N layer was approximately half as large as GaN layers. The impurity and electrical characteristics of the delta doped layers are further discussed.
Nitrogen and phosphorus acquisition by the mycelium of the ectomycorrhizal fungus Paxillus involutus and its effect on host nutrition
- BETTINA BRANDES, DOUGLAS L. GODBOLD, ARND J. KUHN, GEORG JENTSCHKE
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- Journal:
- The New Phytologist / Volume 140 / Issue 4 / December 1998
- Published online by Cambridge University Press:
- 01 December 1998, pp. 735-743
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- December 1998
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The contribution of the extramatrical mycelium to N and P nutrition of mycorrhizal Norway spruce (Picea abies (L.) Karst.) was investigated. Seedlings either inoculated with Paxillus involutus (Batsch) Fr. or non-mycorrhizal were grown in a two compartment sand culture system where hyphae were separated from roots by a 45 μm nylon net. Nutrient solution of the hyphal compartment contained either 1.8 mm NH4+ and 0.18 mm H2PO4− or no N and P. Aluminium added to the hyphal compartment as a tracer of mass flow was not detected in the plant compartment, indicating that measurements of N and P transfer by the mycelium were not biased by solute movement across the nylon net.
The addition of N and P to the hyphal compartment markedly increased dry weight, N and P concentration and N and P content of mycorrhizal plants. Calculating uptake from the difference in input and output of nutrient in solution confirmed a hyphal contribution of 73% and 76% to total N and P uptake, respectively. Hyphal growth was increased at the site of nutrient solution input.
Carbon Nanotube-Based Vacuum Microelectronic Gated Cathode
- Xueping Xu, George R. Brandes
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- Journal:
- MRS Online Proceedings Library Archive / Volume 509 / 1998
- Published online by Cambridge University Press:
- 10 February 2011, 107
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- 1998
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A vacuum microelectronic device containing carbon nanotube electron field-emitters was developed and tested. The gated cathode was fabricated using conventional microelectronics fabrication techniques and a final, self-aligned, in situ carbon nanotube growth step. To our knowledge, this is the first vacuum microelectronics device with carbon nanotube field-emitters grown in situ with a catalytic growth process. The turn-on voltage of the cathode was less than 20 volts and the emission current density at 50 volts was as high as 9 mA-cm−2. The fabrication process, device performance, manufacturing issues and cathode applications will be discussed.
The Importance of United Nations Documentation to Comparative Lawyers
- George Brand
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- Journal:
- International & Comparative Law Quarterly / Volume 19 / Issue 2 / April 1970
- Published online by Cambridge University Press:
- 17 January 2008, pp. 185-204
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- April 1970
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