Bibliothek

X
feed icon rss

Ihre E-Mail wurde erfolgreich gesendet. Bitte prüfen Sie Ihren Maileingang.

Leider ist ein Fehler beim E-Mail-Versand aufgetreten. Bitte versuchen Sie es erneut.

Vorgang fortführen?

Exportieren
Filter
  • Digitale Medien  (169)
  • 1995-1999  (104)
  • 1990-1994  (59)
  • 1975-1979  (6)
  • 1
    Digitale Medien
    Digitale Medien
    Inhomogeneous perturbations and phase resetting in an oscillatory reaction–diffusion system (1990)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 92 (1990), S. 7302-7314 
    Details
    ISSN: 1089-7690
    Quelle: AIP Digital Archive
    Thema: Physik , Chemie und Pharmazie
    Notizen: The response of the Brusselator reaction–diffusion system to inhomogeneous perturbations is studied. The main focus of this work is on a spatial generalization of the phase resetting problem. A randomly chosen fraction p of an initially homogeneous oscillatory system is locally perturbed and driven off the limit cycle. The asymptotic local phase is monitored and averaged over local regions and realizations of the perturbation process. From this information a phase response curve can be constructed which depends both on the local stimulus amplitude and on p. The system exhibits two qualitatively different kinds of response depending on the stimulus amplitude and the phase at which the perturbation is applied. It either relaxes to a spatially homogeneous oscillatory state or develops persistent spatial patterns. The origin of this behavior is discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.458215
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 2
    Digitale Medien
    Digitale Medien
    Phase resetting dynamics for a discrete reaction–diffusion model (1990)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 92 (1990), S. 7315-7322 
    Details
    ISSN: 1089-7690
    Quelle: AIP Digital Archive
    Thema: Physik , Chemie und Pharmazie
    Notizen: The results of a study of spatial pattern formation in a two-dimensional oscillatory reaction–diffusion system are presented. The calculations are carried out on a discrete model of the Brusselator reaction. The system responds to inhomogeneous perturbations in two different ways. For most perturbations it relaxes back to a spatially homogeneous state with a phase shift. However, special perturbations produce persistent structures which consist of spiral waves and target patterns. The nature of these spatio-temporal states is discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.458216
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 3
    Digitale Medien
    Digitale Medien
    Two-dimensional mapping of the plasma density in the upper atmosphere with computerized ionospheric tomography (CIT) : The 39th annual meeting of division of plasma physics of APS (1998)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Plasmas 5 (1998), S. 2010-2021 
    Details
    ISSN: 1089-7674
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: Tomographic imaging of the ionosphere is a recently developed technique that uses integrated measurements and computer reconstructions to determine electron densities. The integral of electron density along vertical or oblique paths is obtained with radio transmissions from low-earth-orbiting (LEO) satellite transmitters to a chain of receivers on the earth's surface. Similar measurements along horizontal paths can be made using transmissions from Global Position System (GPS) navigation satellites to GPS receivers on LEO spacecraft. Also, the intensities of extreme ultraviolet (EUV) emissions can be measured with orbiting spectrometers. These intensities are directly related to the integral of the oxygen ion and electron densities along the instrument line of sight. Two-dimensional maps of the ionospheric plasma are produced by analyzing the combined radio and EUV data using computerized ionospheric tomography (CIT). Difficulties associated with CIT arise from the nonuniqueness of the reconstructions, owing to limited angle measurements or nonoptimal receiver location. Improvements in both reconstruction algorithms and CIT measurement systems are being implemented to overcome these difficulties. New imaging systems being developed employ CIT for large area mapping of the plasma densities in the ionosphere. © 1998 American Institute of Physics.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.872872
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 4
    Digitale Medien
    Digitale Medien
    Vortex dynamics in oscillatory chemical systems (1991)
    Woodbury, NY : American Institute of Physics (AIP)
    Chaos 1 (1991), S. 421-434 
    Details
    ISSN: 1089-7682
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: Vortex core dynamics is studied in the Brusselator both near to and far from the Hopf bifurcation line for random and pair initial conditions. Extensive simulations are carried out for a pair of counter-rotating vortices close to the Hopf bifurcation line. Provided the vortices are not so far apart that wave-front annihilation produces strong gradients between their centers, the simulation results compare favorably with theories based on the complex Ginzburg–Landau equation. Far from the Hopf line the vortex core dynamics changes character and phenomena such as periodic motion of the vortex centers arise.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.165852
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 5
    Digitale Medien
    Digitale Medien
    Optical and structural studies of the effect of spacers in modulation-doped ZnSe/Zn1−xCdxSe quantum wells (1999)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 86 (1999), S. 891-895 
    Details
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: The effect of spacers in modulation-doped Zn1−xCdxSe/ZnSe:Cl multiple quantum wells (MD-MQWs) was investigated by photoluminescence (PL) and time-of-flight secondary-ion-mass spectrometry (TOF-SIMS). A comparison was made between structures with and without spacers as a function of annealing temperature. The diffusion of Cl and Cd was monitored by TOF-SIMS depth profiling and photoluminescence. Although TOF-SIMS does not show any significant diffusion of Cl and Cd in both structures at temperatures up to 385 °C, the PL results indicate the modification of optical properties in the Zn1−xCdxSe/ZnSe:Cl MD-MQWs due to annealing. Up to an annealing temperature of 385 °C, the MD-MQWs with spacers show superior optical quality in the quantum well regions, while quenching of the quantum well band-edge PL and strong enhancement of deep-level emission were observed from the MD-MQWs without spacers. This phenomenon suggests that the radiative deep-level emission may provide more efficient channel for electron–hole recombination with increasing annealing temperature. © 1999 American Institute of Physics.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.370863
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 6
    Digitale Medien
    Digitale Medien
    A frequency modulated mm-wave interferometer with a single sideband upconverter (1999)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 70 (1999), S. 2516-2519 
    Details
    ISSN: 1089-7623
    Quelle: AIP Digital Archive
    Thema: Physik , Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: A frequency modulated interferometer is developed, which uses a 94 GHz Gunn oscillator and a single sideband (SSB) upconverter as a frequency modulator. An SSB upconverter makes it possible to use a heterodyne phase measurement technique with one mm-wave source. In addition, the influence of frequency drift and phase noise of a mm-wave source on the phase measurement can be reduced. In this work, the performance of a SSB upconverter as a frequency modulator is examined. Also, overall performance of the mm-wave interferometer with a SSB upconverter and line density measurement results in a mirror device are described. © 1999 American Institute of Physics.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.1149784
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 7
    Digitale Medien
    Digitale Medien
    Angle chord integral inverter and a rotating type optical probe (1999)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 70 (1999), S. 1730-1734 
    Details
    ISSN: 1089-7623
    Quelle: AIP Digital Archive
    Thema: Physik , Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: The inversion problem of angle dependent chord integrals is theoretically studied and a rotating type optical probe is developed for its application. The proposed solution is computationally efficient and robust to measurement additive noise. The probe system constructed is tested in an inductively coupled plasma source by measuring a spectral line intensity of argon plasma. © 1999 American Institute of Physics.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.1149659
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 8
    Digitale Medien
    Digitale Medien
    Overview of Korea Superconducting Tokamak Advanced Research diagnostics (1999)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 70 (1999), S. 1397-1401 
    Details
    ISSN: 1089-7623
    Quelle: AIP Digital Archive
    Thema: Physik , Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: The Korea Superconducting Tokamak Advanced Research (KSTAR) project is the Korean national fusion program for constructing a superconducting tokamak, that is capable of a steady-state operation. Currently, the KSTAR diagnostic group is concentrating on conceptual design activities to provide measurements of the plasma behavior that is necessary to satisfy the KSTAR missions. A diagnostic overview for the KSTAR device is presented. © 1999 American Institute of Physics.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.1149631
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 9
    Digitale Medien
    Digitale Medien
    A chamber for laboratory studies of atmospheric aerosols and clouds (1996)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 67 (1996), S. 4364-4368 
    Details
    ISSN: 1089-7623
    Quelle: AIP Digital Archive
    Thema: Physik , Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: A stainless-steel chamber has been constructed and interfaced to a Fourier transform infrared spectrometer for the purpose of studying laboratory simulated atmospheric aerosols and clouds. The chamber is cylindrical in design and is comprised of a double-walled inner assembly that resides within an outer vacuum jacket. The volume of the aerosol sample region is 28 L. By circulating refrigerated methanol between the double walls of the inner assembly, constant temperature control of the sample region can be maintained between 187 and 300 K. A study of temperature uniformity within the chamber at 291, 240, and 187 K revealed a standard deviation in temperature of 1.6 K as determined from measurements made using five copper–constantan thermocouples. Good agreement is obtained between thermocouple measured temperatures and rotational temperatures computed from infrared absorption spectra of methane gas. The chamber described here has been used to examine heterogeneous chemistry of solid powder samples. A technique of generating an aerosol sample by rapidly dispersing a solid powder in a gas is presented. The half-life of a γ-alumina aerosol sample was measured to be 25 min. © 1996 American Institute of Physics.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.1147537
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 10
    Digitale Medien
    Digitale Medien
    Proliferating cell nuclear antigen (PCNA) immunoreactivity in ovarian serous and mucinous neoplasms: diagnostic and prognostic value (1993)
    238 Main Street, Cambridge, Massachusetts 02142, USA : Blackwell Scientific Publications
    International journal of gynecological cancer 3 (1993), S. 0 
    Details
    ISSN: 1525-1438
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Sixty-two serous and mucinous ovarian tumors, an admixture of benign, borderline and malignant neoplasms, were immunostained for proliferating cell nuclear antigen (PCNA), with the monoclonal antibody PC10. The PC10 index, the proportion of cells showing nuclear positive staining, was calculated in each case. All the tumors showed positive immunoreactivity for PCNA. There was no overlap of PC10 counts between benign, borderline and malignant serous tumors but within the mucinous group of neoplasms there was considerable overlap between the counts for borderline and malignant tumors. There was no relationship between the PC10 index and the surgical stage of the malignant neoplasms and the index could not be correlated with patient death. Staining for PCNA does not, therefore, appear to be of any prognostic value in ovarian adenocarcinomas.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1046/j.1525-1438.1993.03060391.x
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
Schließen ⊗
Diese Webseite nutzt Cookies und das Analyse-Tool Matomo. Weitere Informationen finden Sie hier...