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  • 1
    Electronic Resource
    Electronic Resource
    Paramagnetism and scaling behavior of volume flux pinning force density in a GdBa2Cu3O6+x thin film (1995)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 78 (1995), S. 3287-3292 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Magnetic measurements have been performed on a GdBa2Cu3O6+x superconducting thin film. The paramagnetism carried by rare earth Gd3+ ions in the film tilts the magnetic hysteresis loop and broadens the width of the magnetic hysteresis ΔM, then the magnetization critical current density and the volume flux pinning force density based on the Bean critical state model deviate from intrinsic values. Therefore, in order to get useful information on the pinning mechanism, correction for the paramagnetism is essential. And after correction for the paramagnetism, a scaling law of the volume flux pinning force density is obtained as f(b)=(b/4)0.5(1−b/4)1.5, based on which the possible pinning mechanism in the film is discussed. In the end, deviation from the scaling law at high fields is interpreted by the collective pinning theory. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.360019
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  • 2
    Electronic Resource
    Electronic Resource
    Study of magnetization relaxation on zone-melted YBa2Cu3O6+x superconductors (1995)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 77 (1995), S. 2618-2624 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The analytical magnetization versus time expressions for several flux-pinning models for high-Tc superconductors are deduced. Magnetic relaxation and hysteresis studies have been performed on a zone-melted YBa2Cu3O6+x sample by SQUID. Nonlogarithmic magnetization decay is observed at relatively high temperatures; we attribute this to the nonlinear U(J) relationship which may arise from the local pinning potential Up(x), rather than collective pinning. At 70 K, the experimental data fits extremely well to the expression M(t)=M0+a(T)ln ln(t/τ) which is the result of the exponential U(J) relationship. Based on this U(J) law, the local pinning potential is determined to be Up(x)=U0(x/x0)[1−ln (x/x0)]. The voltage–current E(J) resulting from the observed U(J) relationship, as well as the role of the Y2BaCuO5 (211) phase in zone-melted YBCO is discussed. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.358726
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  • 3
    Electronic Resource
    Electronic Resource
    Tribenzylammonium dibenzylammonium tetrachlorocuprate (1994)
    Oxford [u.a.] : International Union of Crystallography (IUCr)
    Acta crystallographica 50 (1994), S. 200-202 
    Details
    ISSN: 1600-5759
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1107/S0108270193007735
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  • 4
    Electronic Resource
    Electronic Resource
    Normal Changes in Spinal Bone Mineral Density in a Chinese Population: Assessment by Quantitative Computed Tomography and Dual-Energy X-ray Absorptiometry (1999)
    Springer
    Osteoporosis international 9 (1999), S. 179-187 
    Details
    ISSN: 1433-2965
    Keywords: Key words:Bone mineral density (BMD) – Chinese population – Dual-energy X-ray absorptiometry (DXA) – Normative data – Quantitative computed tomography (QCT)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract: This study was designed to determine age- and gender-based normative values for spinal bone mineral density (BMD) in a Chinese population. In addition, we compared our data with those of other countries and populations. Four hundred and forty-three healthy Chinese subjects, aged 10–79 years (189 males, mean age 46.9 years; 254 females, mean age 45.7 years) were recruited for BMD assessment. BMD was measured by quantitative computed tomography (QCT) and dual-energy X-ray absorptiometry (DXA), including postero-anterior DXA (PA-DXA), lateral DXA (L-DXA) and midlateral DXA (mL-DXA). For both genders, BMD values peaked in the 10–19 year age group when measured by QCT, and in the 30–39 year age group when measured by PA-DXA. BMD values decreased with age after reaching peak bone density in males and females for all measurements, except for PA-DXA in males. Male BMD values by DXA tended to increase beginning with the 60–69 age group through the 70–79 age group whether by PA-DXA, or L-DXA and mL-DXA. However, male QCT data showed stable BMD values among these two older groups. Comparative results showed female QCT data were higher in the 20–39 age group and lower after the 40–49 age group compared with American females. The peak BMD value by PA-DXA in Chinese females was reached in the same age group as American and European females and was similar in magnitude (p 〉 0.05). However, the peak BMD value for Chinese females was reached earlier and was significantly higher than that observed in Japanese females (p 〈 0.001). We conclude that the age group in which the peak BMD values are reached is different depending on the technique used, as is the calculated age-related rate of bone loss. It can be speculated that such differences reflect different timing for bone maturation in cancellous and cortical bone.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001980050133
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  • 5
    Electronic Resource
    Electronic Resource
    Chiral nucleation (1995)
    Springer
    Monatshefte für Chemie 126 (1995), S. 67-73 
    Details
    ISSN: 1434-4475
    Keywords: Chiral crystallization ; Nucleation ; Chiral inorganic salts ; Sodium chlorate ; Sodium bromate ; Optical activity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Die Kristallisation aus agitierten wässrigen Lösungen von Natriumchlorat und-bromat wurde mittels levo- und dextrorotatorischem pulverförmigem Natriumchlorat und -bromat nukleiert. Es entstanden Kristalle mit einem hohen Grad an optischer Reinheit.
    Notes: Summary The crystallization of agitated aqueous solutions of sodium chlorate and sodium bromate was nucleated with levo- or dextrorotatory crystal powders of sodium chlorate and sodium bromate to furnish new crystals with a high degree of chiroptical purity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00811758
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  • 6
    Electronic Resource
    Electronic Resource
    Recent advances in anther culture of Hevea brasiliensis (Muell.-Arg.) (1982)
    Springer
    Theoretical and applied genetics 62 (1982), S. 103-108 
    Details
    ISSN: 1432-2242
    Keywords: Pollen plants ; Chromosome counts ; Callus formation ; Embryoid formation ; Plant regeneration ; Rubber-tree
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The yield of pollen embryoids from cultured Hevea anthers was increased 4 fold by optimizing the proportion of ammonium nitrate to potassium nitrate in the dedifferentiation medium. For optimal differentiation of pollen embryoids, kinetin, 2,4-D and α-naphtalene acetic acid are required. Anther culture for 50 days on the dedifferentiation medium is a prerequisite for the selective development of calli and embryoids from microspores. The determination of chromosome numbers in embryoids, plantlets and regenerated trees reveals that they originate from (poly)haploid pollen grains (n=2x=18). Aneuploid, triploid (3x=27) and tetraploid (4x=36) cells were encountered in increasing frequencies as the embryoids and plants developed. A few haploid cells with 9 chromosomes were consistently observed. Buds from shoots with mixoploid chromosome numbers can be grafted and the change in the chromosome constitution of the developing new shoots followed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00293340
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  • 7
    Electronic Resource
    Electronic Resource
    Measurements of hydrogen peroxide induced premature senescence:senescence-associated β-galactosidase and DNA synthesis index in human diploid fibroblasts with down-regulated p53 or Rb (2000)
    Springer
    Biogerontology 1 (2000), S. 335-339 
    Details
    ISSN: 1573-6768
    Keywords: dose response ; growth arrest ; oxidants ; senescent biomarkers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Human diploid fibroblasts (HDFs) inevitably undergo replicative senescence in culture after serial passages. Recent work indicates that early passage HDFs undergo irreversible growth arrest and develop features of senescence after being treated with oxidants and other agents. Senescence is usually measured by a decrease in DNA synthesis index and an increase in the activity of senescence-associated β-galactosidase (SA β-gal). We compared these two measurements here and found that IMR-90 HDFs lost the ability to synthesize DNA immediately but did not activate SA β-gal until 4 days after the treatment with 75 µM or 0.75 pmol/cell H2O2. Expression of human papillomaviral E6 or/and E7 genes results in reduction of p53 or/and Rb protein levels and increases in ED50 for DNA synthesis inhibition or SA β-gal expression. A small fraction of wild type and E7 expressing cells could not synthesize DNA and did not express SA β-gal one week following the treatment with H2O2 at doses lower than 150 µM or 1.5 pmol/cell. The dose response curve of SA β-gal activation overlapped with that of DNA synthesis inhibition in E6 and E6E7 expressing cells. The results indicate that the expression of SA β-gal correlates with inability of DNA synthesis in the majority of wild type, E6, E7 or E6E7 expressing cells one week after H2O2 treatment.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1026590501344
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  • 8
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    Scattering of relativistic electrons by oblique EMIC waves: Test-particle and full-wave modeling (2023)
    In:  XXVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG)
    Details
    Publication Date: 2023-05-04
    Description: Electromagnetic ion cyclotron (EMIC) emissions in the Earth’s inner magnetosphere are a significant driver of relativistic electron precipitation into the atmosphere. The amplitudes of EMIC waves often exceed 1 nT, introducing nonlinear effects not included in the diffusive quasi-linear theory. While the nonlinear effects have been previously studied analytically and by test-particle simulations, most studies focus on parallel-propagating monochromatic waves. Here we present results from test-particle simulations of relativistic electrons interacting with EMIC waves of different amplitudes and wave normal angles. Diffusive and advective components of pitch-angle scattering are analyzed, highlighting the important effect of harmonic resonances on both co-streaming and counter-streaming electrons. Backward-in-time simulations are used to obtain the perturbed phase space density distribution and study the loss-cone electron population. It is demonstrated that the net effect of advective and diffusive motion during one quarter-bounce results in near isotropization of the distribution unless the nonlinear phase-trapping effects become dominant. It is further revealed that particles below the fundamental resonance energy experience not only nonresonant scattering caused by the amplitude modulations but also fractional-resonant scattering stemming from nonlinearly perturbed trajectories. Finally, the simple monochromatic wave model with constant obliquity is replaced with a full-wave model based on finite-difference time-domain simulations initialized with waveforms from spacecraft measurements. Differences between the two models are discussed, assessing the limitations of monochromatic models in the analysis of relativistic electron scattering and precipitation.
    Language: English
    Type: info:eu-repo/semantics/conferenceObject
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  • 9
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    Investigating Loss of Relativistic Electrons Associated With EMIC Waves at Low L Values on 22 June 2015 (2019)
    In:  Journal of Geophysical Research: Space Physics
    Details
    Publication Date: 2023-02-13
    Type: info:eu-repo/semantics/article
    Format: application/pdf
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  • 10
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    Energetic electron precipitation by waves and field-line scattering as seen from low altitude, polar-orbiting satellites (2023)
    In:  XXVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG)
    Details
    Publication Date: 2023-07-12
    Description: Energetic ion and electron measurements from low-altitude polar-orbiting missions, such as POES, have offered previously a wide range of information on the presence and intensity of equatorial waves and on the presence of field-line curvature scattering and associated magnetospheric topology. Data recently acquired from the dual ELFIN CubeSat mission, offer a much-improved view of magnetospheric scattering of plasma sheet and radiation belt electrons with energies 〉50keV. Significant contribution to relativistic electron precipitation, especially during active times, comes from electromagnetic ion cyclotron (EMIC) waves, and a combination of EMIC and whistler mode chorus waves acting at separate, but occasionally also at the same longitudes. The persistence of EMIC waves at active times suggests they can be a significant contributor to the overall losses, despite their limited latitudinal extent. Non-linear wave-particle interactions can result in abrupt (sub-second), microburst precipitation preferentially at dawn but also at dusk, with high recurrence rates contributing to the net energy input to the atmosphere at active times. Another significant source is from field-line scattering occurring at and just poleward of the isotropy boundary. This mechanism results in persistent scattering at the nightside under all geomagnetic conditions, with fluxes intensifying with activity level. We examine the relative energy deposition and ionization contribution of these sources with respect to activity level, latitude and local time, compared to those of electrons with energies 〈30keV, examined with other datasets.
    Language: English
    Type: info:eu-repo/semantics/conferenceObject
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