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  • 1
    Electronic Resource
    Electronic Resource
    Performance of Beamline 4W1C for x-ray diffuse scattering station at Beijing Synchrotron Radiation Facility : Proceedings of the 5th international conference on synchrotron radiation instrumentation (1995)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 66 (1995), S. 1694-1695 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: Bent triangular Si crystals with an oblique-cut angle 12.16° are used on the beamline 4W1C at Beijing Synchrotron Radiation Facility, to select monochromatic x-rays and to focus the beam in the horizontal direction. The downstream Pt-coated reflective mirror is bent as a cylindroid focuses the beam vertically. Double-focused monochromatic x rays are available on the diffuse scattering station. Specifications of the beamline with the Si (220) monochromator were measured as follows: size of the focus spot—0.5 mm (horizontal)×0.3 mm (vertical), maximum x-ray density—1.6×109 photons/s mm2, and energy resolution of the monochromatic beam—4.4×10−4. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1145886
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  • 2
    Electronic Resource
    Electronic Resource
    Persistent expression of bcl-2 onco-protein in endometrial carcinoma correlates with hormone receptor positivity (1996)
    Suite 500, 5th Floor, 238 Main Street, Cambridge Massachusetts 02142, USA : Blackwell Science Inc.
    International journal of gynecological cancer 6 (1996), S. 0 
    Details
    ISSN: 1525-1438
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The protein product of proto-oncogene bcl-2 is thought to be involved in inhibition of apoptosis and is hormonally regulated in a variety of in vitro and in vivo experiments. The association of bcl-2 persistence and hormone receptor status was investigated by immunocytochemistry from paraffin-embedded tissue in a series of 82 women with endometrial carcinoma and 20 women with benign endometrium. In benign endometrium, bcl-2 immunoreactivity was strongly present in glands of proliferative and hyperplastic endometrium, while a weak signal was detected in secretory endometrium. Bcl-2 expression tends to decrease in staining intensity with progression from benign endometrium, including proliferative and hyperplastic endometrium, to endometrioid carcinoma and to mucinous, clear cell and serous carcinomas of the endometrium. Bcl-2 persistence was observed in the majority (65%) of endometrial carcinomas. We demonstrated a significant correlation of bcl-2 immunoreactivity with estrogen receptor (P = 0.000005) and progesterone receptor status (P = 0.00032). The bcl-2 persistence was found to be significantly higher in FIGO G1 and G2 tumors than in G3 tumors (P = 0.00035), while no significant difference was detected in tumors of different stages. We conclude that bcl-2 persistence is highly correlated with the presence of hormone receptors and may be hormone-dependent or related to hormonal regulation in endometrial carcinomas. Persistent expression of bcl-2 in normal and hyperplastic endometrium and endometrial carcinoma suggests that failure to inactivate bcl-2 expression early in the development of endometrial carcinoma may provide an opportunity for accumulating genetic mutations and evolution from a precursor lesion to invasive carcinoma.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1525-1438.1996.06030235.x
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  • 3
    Electronic Resource
    Electronic Resource
    The effect of interference on magneto-optics in magneto-optical layered structures (1997)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 81 (1997), S. 1956-1961 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: In this article the magneto-optics of magneto-optical (M-O) layered structures have been studied theoretically and experimentally. For the air/M-O/air configuration, an analytic expression between the apparent complex Faraday rotation and the eigenvalue φ˜F=e1φ˜F′ can be obtained, when the M-O layers are semitransparent and weakly magnetic. The interference factor e1 is a function of the optical constants and the M-O layer thickness d, and the light wavelength. In these structures, the apparent Faraday rotation consists of two parts. One oscillates as a function of the M-O layer thickness and the other is proportional to the layer thickness. The oscillation period and the amplitude are determined by the optical constants of the M-O layers. For the air/M-O/reflector configuration, the Kerr rotation φ˜k oscillates as a function of the M-O layer thickness and approaches a constant as the thickness d→∞. If the M-O layers are semitransparent and weakly magnetic, the apparent Kerr rotation can be expressed as φ˜k=e2φ˜F′. For ultrathin metallic magnetic bilayered films the Kerr rotation is proportional to the M-O layer thickness and the enhancement factor is a function of the optical constants of the M-O layer and NM reflector. The magneto-optics of a Co spinel ferrite film, Co/Cu, Fe-Ni/Cu, and Co/Si structures have been studied experimentally. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.364051
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  • 4
    Electronic Resource
    Electronic Resource
    Nanoporous structure of sputter-deposited silicon oxide films characterized by positronium annihilation spectroscopy (2002)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 91 (2002), S. 1704-1706 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Positronium annihilation was applied to characterize the nanoporous structure of thin silicon oxide films sputter-deposited at different argon pressures ranging from 0.1 to 2.0 Pa. At higher argon pressures, the 3γ decay probability of ortho-positronium (o-Ps) was substantially enhanced. A comparison of this result with that obtained for capped samples indicated that: (a) 3γ annihilation is due to the intrinsic decay of o-Ps diffusing out from the film into vacuum and (b) films deposited at high argon pressures contain highly connected, open pores. Positron lifetime spectroscopy measurements on the capped films showed that the characteristic size of the pores can be as large as 2.6 nm, depending on the argon pressure. © 2002 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1428787
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  • 5
    Electronic Resource
    Electronic Resource
    Multiple peak photoluminescence of porous silicon (1993)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 63 (1993), S. 3464-3466 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The photoluminescence (PL) response of porous silicon is usually in the form of a single broad peak. Recently, however, PL response with two peaks has been reported. Here we report the observation of multiple peaks in the PL spectrum of porous silicon. A simple modeling of the line shape indicates that four peaks exist within the response curve, and analysis suggests that the PL of porous silicon is derived from quantum confinement in the silicon crystallites. The line shapes can be due to either minibands within the conduction and valence bands or crystallite size variation or a combination of the two.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.110121
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  • 6
    Electronic Resource
    Electronic Resource
    Ultraviolet emission of silicon quantum tips (1999)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 74 (1999), S. 386-388 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Silicon tips used as field emitters have dimensions that are within the quantum confinement regime. Therefore they can be considered as freestanding silicon tips. In this letter, a photoluminescence spectrum of a 100×100 array of silicon tips was taken at 10 K. Narrow ultraviolet luminescence peaks were observed. Using the empirical pseudopotential homojunction model, it is demonstrated that these luminescence peaks come from energy levels arising from quantum confinement. By fitting the theoretical result to the experimental result, we conclude that the luminescence peaks come from Si quantum tips of about 20 Å in width and that they are covered by silicon dioxide. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.123079
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  • 7
    Electronic Resource
    Electronic Resource
    Stress development during deposition of CNx thin films (1998)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 72 (1998), S. 2532-2534 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We have investigated the influence of deposition parameters on stress generation in CNx (0.3〈x〈0.5) thin films deposited onto Si(001) substrates by reactive magnetron sputtering of C in pure N2 discharges. Film stress, σ, which in all cases is compressive, decreases with an increase in the N2 pressure, PN2, due to structural changes induced by the pressure-dependent variation in the average energy of particles bombarding the film during deposition. The film stress σ is also a function of the film growth temperature, Ts, and exhibits a maximum value of ∼5 GPa at 350 °C. Under these conditions, the films have a distorted microstructure consisting of a three-dimensional, primarily sp2 bonded, network. In contrast, films deposited at Ts〈200 °C with a low stress are amorphous. At 350 °C〈Ts〈600 °C, σ gradually decreases as Ts is increased and the microstructure becomes more graphitic and contains fewer defects. Nanoindentation measurements show that the films grown at 350 °C exhibit the highest hardness and elasticity. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.121410
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  • 8
    Electronic Resource
    Electronic Resource
    Study of double barrier superlattice by synchrotron radiation and double-crystal x-ray diffraction (1996)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 68 (1996), S. 1147-1149 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: An (AlAs/GaAs/AlAs/AlGaAs)/GaAs(001) double-barrier superlattice grown by molecular beam epitaxy (MBE) is studied by combining synchrotron radiation and double-crystal x-ray diffraction (DCD). The intensity of satellite peaks is modulated by the wave function of each sublayer in one superlattice period. Simulated by the x-ray dynamical diffraction theory, it is discovered that the intensity of the satellite peaks situated near the modulating wave node point of each sublayer is very sensitive to the variation of the layer structural parameters. The accurate layer thickness of each sublayer is obtained with an error less than 1 A(ring). Furthermore, x-ray kinematical diffraction theory is used to explain the modulation phenomenon. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.115705
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  • 9
    Electronic Resource
    Electronic Resource
    Lattice strains and composition of self-organized Ge dots grown on Si(001) (2000)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 76 (2000), S. 3397-3399 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: X-ray diffraction measurements at different grazing angles for self-organized Ge dots grown on Si(001) are carried out by using synchrotron radiation as a light source. The lattice parameters parallel and perpendicular to the surface are determined from the grazing angle and ordinary x-ray diffraction spectra. A 1.2% lattice constant expansion parallel to the interface and a 3.1% lattice expansion along the growth direction, as compared with the Si lattice, are found within the Ge dots. Based on the Poisson equation and the Vegard law, the Ge dot should be a partially strain relaxed SiGe alloy with the Ge content of 55%. The composition change in Ge dots is suggested to be caused by the atomic intermixing during the islanding growth. In the small grazing angle x-ray diffraction spectrum, a peak located at the higher angle side of Si(220) is observed. The origin of this peak is attributed to the near surface compressive strain in the peripheral substrate regions surrounding the Ge dots. This compressive strain is induced by the formation of Ge dots and leads to a −0.8% lattice constant change parallel to the interface. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.126658
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  • 10
    Electronic Resource
    Electronic Resource
    Calcium Channels in Smooth Muscle (1989)
    Oxford, UK : Blackwell Publishing Ltd
    Annals of the New York Academy of Sciences 560 (1989), S. 0 
    Details
    ISSN: 1749-6632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Natural Sciences in General
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1749-6632.1989.tb24099.x
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