51,015 research outputs found
Kurzweil-Henstock type integral on zero-dimensional group and some of its applications
No full textsummary:A Kurzweil-Henstock type integral on a zero-dimensional abelian group is used to recover by generalized Fourier formulas the coefficients of the series with respect to the characters of such groups, in the compact case, and to obtain an inversion formula for multiplicative integral transforms, in the locally compact case
Can one detach a fully adsorbed flexible polymer chain by an ultra-small external force?
No full textFull adsorption of flexible chains onto typical solid substrates occurs at a surface interaction energy of (5-10) kBT. The corresponding detachment force is in the range 10-50 pN. In contrast to bare solid substrates common to non-living materials, surfaces coated with brush-like polymer layers are very common in biological soft matter. We employ a simple mean-field approach to describe the effects of weak attraction between a floating long macromolecule and the brush. We show that even for a moderately thick brush a very small effective attraction is enough to produce complete binding of the long chain. The detachment force scales as , where W is the brush thickness. Hence the force could be 1 to 2 orders of magnitude smaller than in the case of typical solid substrates. © Copyright EPLA, 2013.ALEXANDER S, 1977, J PHYS-PARIS, V38, P983, DOI 10.1051-jphys:01977003808098300; Arita T, 2010, NANOSCALE, V2, P1467, DOI 10.1039-c0nr00157k; BHATTACHARYA S., 2008, EUR PHYS J E, V29, P285; Bhattacharya S, 2009, PHYS REV E, V79, DOI 10.1103-PhysRevE.79.030802; Bhattacharya S, 2009, MACROMOLECULES, V42, P2236, DOI 10.1021-ma8024392; Binder K, 2012, J POLYM SCI POL PHYS, V50, P1515, DOI 10.1002-polb.23168; Bockelmann U, 2002, BIOPHYS J, V82, P1537; Bruce A., 2002, MOL BIOL CELL; Chen M, 2009, SCIENCE, V323, P1698, DOI 10.1126-science.1169399; DEGENNES PG, 1980, MACROMOLECULES, V13, P1069, DOI 10.1021-ma60077a009; Hugel H, 2001, MACROMOL RAPID COMM, V22, P989; Klein J, 2006, P I MECH ENG J-J ENG, V220, P691, DOI 10.1243-13506501JET143; Klushin LI, 2013, PHYS REV E, V87, DOI 10.1103-PhysRevE.87.022604; Kufer SK, 2008, SCIENCE, V319, P594, DOI 10.1126-science.1151424; Landau L D, 1977, QUANTUM MECH NONRELA, V3; Milchev A, 2010, J CHEM PHYS, V132, DOI 10.1063-1.3414996; Pasch H, 1999, HPLC POLYM; Reitsma S, 2007, PFLUG ARCH EUR J PHY, V454, P345, DOI 10.1007-s00424-007-0212-8; Rubinstein M, 2003, POLYM PHYS; Skvortsov AM, 2010, J CHEM PHYS, V132, DOI 10.1063-1.3308626; Skvortsov AM, 2009, J CHEM PHYS, V130, DOI 10.1063-1.311060410
The escape transition of a polymer: A unique case of non-equivalence between statistical ensembles
No full textA flexible polymer chain under good solvent conditions, end-grafted on a flat repulsive substrate surface and compressed by a piston of circular cross-section with radius L may undergo the so-called escape transition when the height of the piston D above the substrate and the chain length N are in a suitable range. In this transition, the chain conformation changes from a quasi-two-dimensional self-avoiding walk of blobs of diameter D to an inhomogeneous flower state, consisting of a stem (stretched string of blobs extending from the grafting site to the piston border) and a crown outside of the confining piston. The theory of this transition is developed using a Landau free-energy approach, based on a suitably defined (global) order parameter and taking also effects due to the finite chain length N into account. The parameters of the theory are determined in terms of known properties of limiting cases (unconfined mushroom, chain confined between infinite parallel walls). Due to the non-existence of a local order parameter density, the transition has very unconventional properties (negative compressibility in equilibrium, non-equivalence between statistical ensembles in the thermodynamic limit, etc.). The reasons for this very unusual behavior are discussed in detail. Using Molecular Dynamics (MD) simulation for a simple bead-spring model, with N in the range 50 \leq N \leq 300 , a comprehensive study of both static and dynamic properties of the polymer chain was performed. Even though for the considered rather short chains the escape transition is still strongly rounded, the order parameter distribution does reveal the emerging transition clearly. Time autocorrelation functions of the order parameter and first passage times and their distribution indicate clearly the strong slowing down associated with the chain escape. The theory developed here is in good agreement with all these simulation results. © 2009 EDP Sciences, SIF, Springer-Verlag Berlin Heidelberg.Abbou J, 2006, J PHYS CHEM B, V110, P22664, DOI 10.1021-jp064559i; Allen M. P., 1987, COMPUTER SIMULATIONS; Balescu R., 1975, EQUILIBRIUM NONEQUIL; Baumgartner W, 2000, P NATL ACAD SCI USA, V97, P4005, DOI 10.1073-pnas.070052697; Binder K., 1995, MONTE CARLO MOL DYNA; BINDER K, 1987, REP PROG PHYS, V50, P783, DOI 10.1088-0034-4885-50-7-001; Bird R. 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Speculu[m] exemploru[m] ex diuersis libris in vnu[m] laboriose collectu[m].
No full textEerste blad (blanco) ontbreektThe author is probably Johannes Busch (CIBN)Titel uit incipit. Drukker en datum uit colofonBMC: Catalogue of books printed in the XVth century now in the British Museum I 226bGesamtkatalog der Wiegendrucke ; M42951Machiels, J. Catalogus van de boeken gedrukt vóór 1600 ; S 488Polain, M.-L. Catalogue des livres imprimé au 15e siècle ... ; 3574Europeana-GoogleBook
A study of bending effect on the femtosecond-pulse inscribed fiber Bragg gratings in a dual-core fiber
No full textFiber Bragg gratings with different reflection wavelengths have been inscribed in different cores of a dual-core
fiber section. The effect of fiber bending on the FBG reflection spectra has been studied. Various interrogation
schemes are presented, including a single-end scheme based on a cross-talk between the cores that uses only
standard optical components. Simultaneous interrogation of the FBGs in both cores allows to achieve a bending
sensitivity of 12.8 pm/m−1, being free of temperature and strain influence. The technology enables the development
of real-time bending sensors with high spatial resolution based on series of FBGs with different wavelength
inscribed along the multi-core fiber
Raman fiber laser based on dual-core fiber with fiber Bragg grating inscribed by femtosecond radiation
No full textApplication of femtosecond point-by-point inscription technique make it possible to form fiber Bragg gratings (FBGs) in different cores of multicore fibers as mirrors of laser cavity. In this paper, we present various configurations of Raman laser based on dual-core fiber. Due to the use of the inscribed FBG in the cavity of dual-core fiber, lasing threshold is reduced and the output power stability is increased, comparing to existing schemes
JETP Letters V. 67, I .02
No full textJETP Letters -- January 25, 1998
Volume 67, Issue 2, pp. 99-170
Nuclear fusion in the mesic molecule dµ3He
L. N. Bogdanova, S. S. Gershtein, and L. I. Ponomarev
Full Text: PDF (121 kB)
Anomalous polarization of Raman scattering spectra from porous silicon
M. E. Kompan, V. B. Kulik, I. I. Novak, J. Salonen, and A. V. Subashiev
Full Text: PDF (96 kB)
Effect of hole–hole scattering on the conductivity of the two-component 2D hole gas in GaAs/(AlGa)As heterostructures
S. S. Murzin, S. I. Dorozhkin, G. Landwehr, and A. C. Gossard
Full Text: PDF (103 kB)
Optical phonons in quantum-wire structures
A. Milekhin, Yu. Pusep, Yu. Yanovskii, V. Preobrazhenskii, and B. Semyagin
Full Text: PDF (88 kB)
On the nature of the gamma–alpha phase transition in cerium
G. Eliashberg and H. Capellmann
Full Text: PDF (138 kB)
Weak antilocalization in a 2D electron gas with chiral splitting of the spectrum
M. A. Skvortsov
Full Text: PDF (130 kB)
Critical velocity and event horizon in pair-correlated systems with "relativistic" fermionic quasiparticles
N. B. Kopnin and G. E. Volovik
Full Text: PDF (96 kB)
Scanning tunneling spectroscopy of charge effects on semiconductor surfaces and atomic clusters
N. S. Maslova, S. I. Oreshkin, V. I. Panov, S. V. Savinov, A. Depuydt, and C. Van Haesendonck
Full Text: PDF (197 kB)
Oscillations of the magnetoresistance in an inclined magnetic field for MIS structures on (100) silicon with a high electron density
S. G. Semenchinskii, L. Smrcka, P. Vasek, and L. Jansen
Full Text: PDF (80 kB)
A simple approach to the evaluation of the Hall conductivity in impure metals within the Green function formalism
V. M. Edelstein
Full Text: PDF (110 kB)
Characteristic features of microcontact spectra of contacts between a metal and a quasi-1D conductor with a charge density wave
A. A. Sinchenko, Yu. I. Latyshev, S. G. Zybtsev, and I. G. Gorlova
Full Text: PDF (89 kB)Archived web conten
Impact papers on aging in 2009
No full textThe editorial board of Aging reviews research papers published in 2009,which they believe have or will have a significant impact on aging research.Among many others, the topics include genes that accelerate aging or incontrast promote longevity in model organisms, DNA damage responsesand telomeres, molecular mechanisms of life span extension by calorierestriction and pharmacologic interventions into aging. The emergingmessage in 2009 is that aging is not random but determined by agenetically-regulated longevity network and can be decelerated bothgenetically and pharmacologically
Random raman fiber laser based on a twin-core fiber with FBGs inscribed by femtosecond radiation
No full textNarrowband Raman lasing in a polarization-maintaining two-core fiber (TCF) is demonstrated. Femtosecond point-by-point inscription of fiber Bragg gratings (FBGs) in individual cores produces a half-open cavity with random distributed feedback. The laser linewidth in the cavity with a single FBG inscribed in one core of the TCF reduced by ∼2 times with respect to the cavity with a fiber loop mirror. It is shown that the inscription of two FBGs in different cores leads to the formation of a Michelson-type interferometer, leading to the modulation of generation spectra near threshold. This technique offers new possibilities for spectral filtering or multi-wavelength generation
The long-wavelength view of GG Tau A: rocks in the ring world
No full textWe present the first detection of GG Tau A at centimetre wavelengths, made with the Arcminute Microkelvin Imager Large Array at a frequency of 16 GHz (λ = 1.8 cm). The source is detected at >6 σrms with an integrated flux density of S16GHz = 249 ± 45 µJy. We use these new centimetre-wave data, in conjunction with additional measurements compiled from the literature, to investigate the long-wavelength tail of the dust emission from this unusual protoplanetary system. We use an MCMC-based method to determine maximum likelihood parameters for a simple parametric spectral model and consider the opacity and mass of the dust contributing to the microwave emission. We derive a dust mass of Md ~ 0.1 Msun, constrain the dimensions of the emitting region and find that the opacity index at λ > 7 mm is less than unity, implying a contribution to the dust population from grains exceeding ~4 cm in size. We suggest that this indicates coagulation within the GG Tau A system has proceeded to the point where dust grains have grown to the size of small rocks with dimensions of a few centimetres. Considering the relatively young age of the GG Tau association in combination with the low derived disc mass, we suggest that this system may provide a useful test case for rapid core accretion planet formation models
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