6,461 research outputs found

    ABSENCE OF REENTRANCE IN THE TWO-DIMENSIONAL XY-MODEL WITH RANDOM PHASE SHIFT

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    We show, that the 2D XY-model with random phase shifts exhibits for low temperature and small disorder a phase with quasi-long-range order, and that the transition to the disordered phase is {\it not} reentrant. These results are obtained by heuristic arguments, an analytical renormalization group calculation, and a numerical Migdal-Kadanoff renormalization group treatment. Previous predictions of reentrance are found to fail due to an overestimation of the vortex pair density as a consequence of independent dipole approximations. At positions, where vortex pairs are energetically favored by disorder, their statistics becomes effectively fermionic. The results may have implications for a large number of related models.Comment: 5 pages, latex, with 2 figures, one author added, minor text changes, to be published in J. de Physique

    Interview with Charles C. King

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    An interview with Charles C. King on May 14, 1962 at Hays, KS 00:00:00 - Introduction and biographical information 00:02:10 - Life as a barber in Hays 00:03:30 - Story about Buffalo Bill\u27s Wild West Show 00:08:16 - Old Fort Hays 00:13:12 - Old Hays and his family history 00:16:47 - The last buffalo calf in Ellis County and early businesses 00:19:59 - School experiences 00:27:52 - Boxing in the barbershop 00:35:31 - Playing football against the Russell team 00:38:08 - Experience as a drum major and trip to Washington D.C. 00:44:35 - Social life in Hays: Dances, banquets, picnics, and shows 00:46:33 - Local economy: Jobs, wages, prices 00:54:33 - Availability of medical carehttps://scholars.fhsu.edu/sackett/1075/thumbnail.jp

    Interview of George King

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    An interview with George King of Hays, KS on May 13, 1962 00:00:04 - Introduction and biographical information 00:04:39 - Career as a pharmacist 00:20:00 - Parents 00:22:06 - A shooting on the day of his mother\u27s arrival from Germany 00:23:54 - Boothill on 18th street in Hays and locally famous murders 00:26:39 - Discussion of photos shown to interviewers of local theatrical productions 00:33:09 - Local football 00:37:14 - James Farm 00:43:20 - Meeting Vice President Charles Curtis 00:48:53 - Law enforcement in the early days of Hays - Wild Bill Hickok 00:54:25 - Relations with Indigenous Americans 00:54:59 - Buffalo soldiers of the 9th Cavalry 00:57:06 - Storms and blizzards 00:58:02 - Robberies in old Hays 00:59:39 - Anecdote about bugs used for red coloring 01:02:00 - Prostitutes exhumed from Boot Hill (racially insensitive language) 01:07:53 - Parts in theatrical productions 01:10:11 - Hachmeier family and the 9th Cavalry (racially insensitive language) 01:13:16 - Charles Curtis and the experiment station 01:16:05 - Mary Middlekauff as a source 01:17:28 - Brother Charlie 01:17:45 - Social life in early Hayshttps://scholars.fhsu.edu/sackett/1062/thumbnail.jp

    Probing the Mechanisms of Fibril Formation Using Lattice Models

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    Using exhaustive Monte Carlo simulations we study the kinetics and mechanism of fibril formation using lattice models as a function of temperature and the number of chains. While these models are, at best, caricatures of peptides, we show that a number of generic features thought to govern fibril assembly are present in the toy model. The monomer, which contains eight beads made from three letters (hydrophobic, polar, and charged), adopts a compact conformation in the native state. The kinetics of fibril assembly occurs in three distinct stages. In each stage there is a cascade of events that transforms the monomers and oligomers to ordered structures. In the first "burst" stage highly mobile oligomers of varying sizes form. The conversion to the aggregation-prone conformation occurs within the oligomers during the second stage. As time progresses, a dominant cluster emerges that contains a majority of the chains. In the final stage, the aggregation-prone conformation particles serve as a template onto which smaller oligomers or monomers can dock and undergo conversion to fibril structures. The overall time for growth in the latter stages is well described by the Lifshitz-Slyazov growth kinetics for crystallization from super-saturated solutions.Comment: 27 pages, 6 figure

    Microbial-Physical Synthesis of Fe and Fe3O4 Magnetic Nanoparticles Using Aspergillus niger YESM1 and Supercritical Condition of Ethanol

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    Magnetic Fe and Fe3O4 (magnetite) nanoparticles are successfully synthesized using Aspergillus niger YESM 1 and supercritical condition of liquids. Aspergillus niger is used for decomposition of FeSO4 and FeCl3 to FeS and Fe2O3, respectively. The produced particles are exposed to supercritical condition of ethanol for 1 hour at 300∘ C and pressure of 850 psi. The phase structure and the morphology measurements yield pure iron and major Fe3O4 spherical nanoparticles with average size of 18 and 50 nm, respectively. The crystal size amounts to 9 nm for Fe and 8 nm for Fe3O4. The magnetic properties are measured to exhibit superparamagneticand ferromagnetic-like behaviors for Fe and Fe3O4 nanoparticles, respectively. The saturation magnetization amounts to 112 and 68 emu/g for Fe and Fe3O4, respectively. The obtained results open new route for using the biophysical method for large-scale production of highly magnetic nanoparticles to be used for biomedical applications
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