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  • 1995-1999  (102)
  • 1990-1994  (81)
  • 1975-1979  (20)
  • 1950-1954  (2)
  • 1
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  It is generally accepted that early human prostate cancers reveal higher androgen dependency than do advanced ones. In the present study, we examined whether the animal model of prostate cancer has already lost androgen dependency at the early stages of carcinogenesis. At experimental week 46, androgen deprivation was induced in rats and the incidences of atypical hyperplasia and cancer were examined in the ventral, dorsolateral prostate, coagulating glands, and seminal vesicles. Androgen deprivation significantly lowered the incidence of atypical hyperplasia in all four organs. As for the incidence of cancer, no significant differences were observed in the coagulating glands and seminal vesicles. Regarding atypical hyperplasia, androgen deprivation significantly decreased the proliferative cell nuclear antigen labeling index in the coagulating gland and seminal vesicles. The presence of cancer was also decreased in the coagulating gland but not in the seminal vesicles. With control group specimens, more intense staining of androgen receptor was observed in atypical hyperplasias than in cancers. Compared with the atypical hyperplasias, the cancers revealed low androgen dependency at the early stages of carcinogenesis. The cancers in the seminal vesicles also revealed higher androgen independency than did those in the coagulating gland.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The structure, soft magnetic properties, magnetostriction, grain size and volume fraction of the residual amorphous phase have been studied for an amorphous Fe91Zr7B2 alloy annealed for periods of 60 s–1080 ks, at temperatures of 823–973 K. The highest permeability (at 1 kHz and 0.4 A/m) 31,000 and smallest coercivity 4.2 A/m are obtained for the sample annealed at 923 K for 60 s, where a small grain size (≈12 nm) and about 35% of the residual amorphous phase are measured. The coercivity of the nanocrystalline alloy varies as the 3rd power of the grain size, corresponding to the case where the magnetically coupled region has a dimensionality between two and three. This slightly low dimensionality is presumed to be due to the alignment of the magnetization in the sample plane. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 79 (1996), S. 6270-6272 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We have investigated the local structural anisotropy of Tb/Fe multilayers using linear polarized synchrotron radiation. X-ray absorption measurements were performed at Fe K edge (7.1 keV) using normal and glancing angle incident photon. From the Fe extended x-ray absorption fine structure (EXAFS), the local structural anisotropy was found for all multilayers as a slight difference of oscillation amplitude between the two incident directions. From the Fourier transformed EXAFS spectra, it is found that the local structural anisotropy shows the maximum at bilayer period of about 1 nm, where perpendicular magnetic anisotropy also shows the maximum value in various rare-earth/transition metal multilayers. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 85 (1999), S. 4400-4402 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The relationship between the mean hyperfine field of the residual intergranular amorphous phase 〈Bhf〉 and the coercivity Hc in various nanocrystalline soft magnetic samples has been investigated in order to clarify the effect of the spontaneous magnetization in the grain boundary region on their magnetic softness. Nanocrystalline samples with various 〈Bhf〉 values were prepared by annealing an amorphous Fe91Zr7B2 precursor for periods of 60 s–108 ks, at temperatures of 823–973 K. Hc shows a clear tendency to decrease with increasing 〈Bhf〉 or decreasing volume fraction of the residual amorphous phase. These effects of the residual amorphous phase on Hc are well understood within the framework of our extended two-phase random anisotropy model where both the exchange stiffness constant and volume fraction of the grain boundary phase are relevant to the exchange correlation length. Our results indicate that the exchange stiffness constant of the intergranular region varies as the square of the spontaneous magnetization of the residual amorphous phase. A small exchange stiffness constant on the order of 10−13 J/m is predicted for the residual amorphous phase in the Fe–Zr–B alloy. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 86 (1999), S. 5726-5732 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Co-cluster-assembled films have been prepared using a size-controllable cluster beam deposition system, by which monodispersed Co clusters with a mean diameter, d=6–13 nm are available. Their morphology and magnetic properties have been studied by scanning electron microscopy (SEM), small-angle x-ray scattering (SAXS) and magnetization measurements. The SEM images show that the film has a porous structure consisting of fine grains without a columnar texture and its density is about 25% of the bulk Co. The SAXS measurements indicate that monodispersivity of the incident clusters is maintained through their assembling process only for d=13 nm. All the specimens exhibit ferromagnetic behavior at room temperature and the magnetic coercive field Hc rapidly increases with decreasing temperature: Hc=168 kA/m (2.1 kOe) at 5 K. Such an enhancement in Hc is ascribed to the exchange anisotropy which arises from the antiferromagnetic Co–oxide layers covering the Co clusters, and to the assemblies of single-domain ferromagnetic clusters with the structure modification and magnetic interaction among them. The monotonic increase in Hc at 300 K with increasing d is simply understood in terms of the single-domain particle theory. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 72 (1992), S. 4548-4555 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The origins of electrons and ions in uranium vapor generated by electron-beam evaporation have been determined. Measurements were made for the electron emission current due to high-energy electron-beam irradiation on a uranium surface (backscattered electrons, etc.), thermionic emission current from the melt surface, and electron current due to vapor ionization. Comparison of these currents confirmed that vapor ionization was the main electron generation process at evaporation surface temperatures above 2200 K. The ionized vapor formed a weakly ionized plasma of very low electron temperature: The degree of ionization ≤1%, electron temperature ≤0.3 eV. The electron-impact ionization process contributed mainly to plasma formation. Beam electrons, their backscattered electrons, and secondary electrons from the beam-irradiated uranium surface were the source electrons for this process. Thermal ionization was the next major process. In addition to the plasma formation model, plasma behavior in vapor was described by a one-dimensional symmetric expansion model. The calculated degree of ionization was in good agreement with the measured value over a wide range of evaporation temperatures and electron-beam currents.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 68 (1990), S. 2735-2738 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A hot wall technique was applied to grow very thin BiI3 single crystals about 100–1000 A(ring) thick by the achievement of low-temperature growth. The so-called van der Waals epitaxy became possible by employing layered materials such as PbI2 and CdI2 as substrate. BiI3 thin films grown with optimized conditions exhibited a sharp band-edge direct exciton absorption line of 30-meV half-width, which is much sharper than that of a single crystal grown by a conventional method reported so far. The transmission electron diffraction measurements were carried out on the films. It was revealed that highly perfect single crystals with a 4-mm diameter size were obtained.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 58 (1991), S. 654-655 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The crystal growth mechanism in Bi-Sr-Ca-Cu-O thin films has been revealed by sequential deposition with an electron cyclotron resonance (ECR) oxygen plasma using in situ reflection high-energy electron diffraction (RHEED) observation. A series of RHEED patterns presents clear evidence that the unit cell of the Bi-Sr-Ca-Cu-O structure is completed as the Bi layers have sandwiched Sr, Ca, and Cu layers. This crystalline process is not an atomic layer by atomic layer growth but a "unit cell by unit cell'' growth.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 68 (1990), S. 6331-6335 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Substrate bias voltages were found to be significantly effective in preparing high-quality laser-deposited superconducting Ba2Y1Cu3O7−δ films at reduced substrate temperatures. The zero-resistance temperature of the biased films, positive bias being more effective than negative, decreased very slightly when the substrate temperature was lowered, whereas that of the unbiased films decreased considerably. In addition, the surface morphology and c-axis orientation have been improved by applying substrate bias voltages. Bias voltages within ±500 V hardly affect the composition of the resulting films so that stoichiometric films have been obtained from a stoichiometric target. A time-resolved optical observation revealed that a short time emission, probably being oxygen plasma, occurred in a few μs after the laser pulse impingement. The improvement in crystallinity of the resulting films is attributed to this emission. The velocity of emissive species in the plume was determined to be 6×105 cm/s. Under positive-biased conditions slower components with a velocity of 3×105 cm/s or less were also observed.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 85 (1999), S. 8349-8352 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We report structural and optical properties of GaSb/GaAs self-assembled quantum dots (QDs) grown by molecular beam epitaxy. The QDs, with nanometer-scale dimensions, were characterized by atomic force microscopy. Furthermore, in photoluminescence (PL) measurements the feature from the QDs was observed at ∼1.1 eV, clearly separated from that of the wetting layer at ∼1.3 eV. With increasing excitation power, the peak from the QDs displayed a large shift towards higher energy. In addition, the temperature dependence of PL yielded a large thermal activation energy, 130 meV, confirming the strong localization of excitons in the QDs. © 1999 American Institute of Physics.
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