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  • 1
    Electronic Resource
    Electronic Resource
    Crystal structure of poly(p-phenylene) prepared by organometallic technique (1992)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 30 (1992), S. 293-297 
    Details
    ISSN: 0887-6266
    Keywords: poly(p-phenylene) from organometallic polymerization, crystal structure of ; crystal structure of poly(p-phenylene) from organometallic preparation ; X-ray diffraction of organometallically produced poly(p-phenylene) ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The two-dimensional crystal structure of poly(p-phenylene) is investigated by linkedatom Rietveld analysis of the x-ray diffraction powder profile. Two molecular chains are packed in a rectangular pgg unit cell (a = 0.779 nm; b = 0.551 nm) with a paracrystalline shift distortion along the chain axis. The molecular conformation is not rigidly planar; rotations between adjacent phenyl-ring planes in a molecule alternate with an angle of about 20°. The setting angle between the mean molecular plane and the a axis is 55.5°.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/polb.1992.090300309
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  • 2
    Electronic Resource
    Electronic Resource
    Effects of Cerebral Ischemia on Regional Dopamine Release and D1 and D2 Receptors (1993)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 60 (1993), S. 0 
    Details
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: To expand on the nature of regional cerebral vulnerability to ischemia, the release of dopamine (DA) and dopaminergic (D1 and D2) receptors were investigated in Mongolian gerbils subjected to bilateral carotid artery occlusion (15 min) alone or with reflow (1–2 h). Extracellular cortical and striatal content of DA and its metabolites was measured by microdialysis using HPLC with electrochemical detection. The kinetic properties of D1 and/or D2 receptor binding sites were determined in cortical and striatal membranes with the use of radiolabeled ligands (125I-SCH23982 and [3H]YM-09151-2, respectively). The ischemic release of DA from the striatum was greater (400-fold over preischemic level) than that from the cortex (12-fold over preischemic content). The affinity for the D1-receptor ligand was lower (KD= 1.248 ± 0.047 nM) after ischemia than that for sham controls (KD= 0.928 ± 0.032 nM, p 〈 0.001). The number of binding sites for D2 receptors decreased in striatum (Bmax= 428 ± 18.4 fmol/mg of protein) after ischemia compared with sham controls (Bmax= 510 ± 25.2 fmol/mg of protein, p 〈 0.05). D1 or D2 binding sites were not changed either in the ischemic cortex or postischemic striatum and cortex. The findings strongly suggest that the ischemic release of DA from striatum is associated with early transient changes in D1- and D2-mediated DA neurotransmission.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1471-4159.1993.tb03311.x
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  • 3
    Electronic Resource
    Electronic Resource
    A Monte Carlo study of the pattern formation during transitions in n-alkane crystals (2000)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 112 (2000), S. 7627-7633 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The rotator phase transition in n-alkane was recently found to show a characteristic pattern of preferred growth along the b-axis (shorter axis) of the unit cell. In order to investigate the origin of this anisotropic growth, a pattern formation in n-alkane crystal is studied during the transition between the low temperature orthorhombic (LO) phase and the rotator (R) phase by use of the Monte Carlo method. Of possible factors that will influence the growth pattern, we here concentrate on the mode of chain packing by assuming that the chains have rigid planar zigzag conformation and are placed in a regular orthohexagonal lattice. The herringbone order in the LO phase is found to develop rather quickly resulting characteristic domains with the (100) and (110) boundaries. The domain boundaries run preferentially along the b-axis at lower temperatures and are considered as a stacking fault or antiphase boundary. The transition between the LO phase and the R phase is found to exhibit a characteristic pattern, where the R phase domains grow preferentially along the b-axis. All these behaviors are shown to originate from different energies of the (100) and (110) boundaries. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.481357
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  • 4
    Electronic Resource
    Electronic Resource
    Imaging Bragg spectrometer for pinched plasma experiments (1994)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 65 (1994), S. 3761-3765 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A compact Bragg spectrometer for monochromatic imaging in the soft x-ray region was designed and examined. With this spectrometer, a pinhole image is simultaneously recorded with a monochromatic image. This makes it possible to easily identify the wavelength when the location of the soft x-ray source fluctuates from shot to shot, such as in the plasma focus and Z-pinch plasma. An rubidium acid phtalate (RAP) flat crystal was examined and monochromatic images of the argon K lines around 4 A(ring) were successfully obtained and displayed. The resolution power and dispersion obtained in situ were compared with the calculated values. © 1994 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1144503
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  • 5
    Electronic Resource
    Electronic Resource
    Development of a large volume negative-ion source for ITER neutral beam injector : Papers from the Ninth International Conference on Ion Sources (2002)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 73 (2002), S. 1090-1092 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: Development of the negative-ion sources has been conducted to realize a high power neutral beam injector for International Thermonuclear Experimental Reactor (ITER). A high negative-ion current density of 31 mA/cm2 (H−) at a very low pressure of 0.1 Pa has been produced in a cesium seeded multicusp plasma generator which has the same concept of the ITER source. For a vacuum insulated accelerator, a voltage holding experiment of long distance vacuum gaps up to ∼1.8 m has been performed. It was clarified that the transition region of product pressure distance (pd) from the vacuum breakdown to the gas discharge is about 0.2 Pa m which is high enough from the operating region of the ITER source. A prototype vacuum insulated accelerator was fabricated based on the experiment and tested. A high-energy H− beam acceleration up to 970 keV, 37 mA, and 1 s has been successfully demonstrated. © 2002 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1431422
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  • 6
    Electronic Resource
    Electronic Resource
    An application of electrically cooled Si detector to fast neutral measurement on CHS : Papers from the thirteenth topical conference on high temperature plasma diagnostics (2001)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 72 (2001), S. 615-618 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A new type of fast neutral particle analyzer using Si diode cooled by Peltier module has been designed and developed. It is known that leak current in a solid-state detector is reduced by its use in low temperature. It is shown in this article that Peltier effect provides a very handy way of cooling the detector as long as a temperature around 0 °C is aimed at. The detector was easily cooled down to −1.6 °C and the performance of the detector was studied by the use of x/γ rays from 241Am. The leak current was remarkably reduced as the detector is cooled improving energy resolution from 9.2 keV at room temperature to 4.3 keV at −1.6 °C. In addition, the lower detectable energy limit was expanded from 25 keV to 14 keV. A Si detector is also sensitive to visible light and x ray. Therefore, the detector of our "reference design" is furnished with an evaporated 1000-Å-thick aluminum layer to reduce the visible light and with a lead collimator to reduce the x ray. The detector was finally installed on the Compact Helical System device for a test of overall performance and an energy spectrum from a diagnostic neutral beam was successfully measured. This test was conducted without an Al layer and this result suggests a possibility of eliminating it. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1316761
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  • 7
    Electronic Resource
    Electronic Resource
    Development and energy calibration of Si-FNA for LHD fast ion measurement : Papers from the thirteenth topical conference on high temperature plasma diagnostics (2001)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 72 (2001), S. 788-791 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A Si-FNA (silicon-diode-based fast neutral analyzer) was newly developed at NIFS, which uses an electrically cooled silicon-diode as an energy analyzer. Si-FNA is suitable for energy-resolved profile measurements of fast neutrals since it is compact and inexpensive. Two Si-FNAs were recently designed and installed on the Large Helical Device (LHD) during the experimental campaign of 1999. The basic performance of a Si-FNA was examined by using x/γ-ray sources of 57Co and 241Am. An energy resolution of about 3.5 keV was achieved for optimum shaping times and a resolution of about 6 keV was achieved for shorter shaping times which allowed for the higher counting rates required for LHD. The energy calibration for fast neutrals was performed by injecting neutral beams (NB) into the LHD vessel without target plasmas present. An energy loss of about 37 keV and an energy broadening of about 4.5 keV were observed at the calibration. Excellent slowing-down energy spectra are obtained for NB-injected fast particles without any influences of x/γ-rays. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1326007
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  • 8
    Electronic Resource
    Electronic Resource
    Morphology and growth process of thermally induced oxide precipitates in Czochralski silicon (1993)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 74 (1993), S. 5437-5444 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The morphology and growth process of oxide precipitates in Czochralski silicon have been studied with prolonged thermal treatments up to 700 h at intermediate temperatures (700–900 °C). It was found with transmission electron microscopy observation that (i) the morphology of precipitates changes from platelet to aggregation of polyhedra at both 800 and 900 °C during isothermal heat treatment, and (ii) the growth of platelet precipitates follows a t1/2 law.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.354254
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  • 9
    Electronic Resource
    Electronic Resource
    Thermally stimulated exoelectron emission from silicon subjected to argon plasma treatment (1993)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 73 (1993), S. 7482-7486 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We have investigated the thermally stimulated exoelectron emission (TSEE) from Ar plasma-treated Si by x-ray photoelectron spectroscopy and by employing a theoretical equation. The sample surfaces were exposed to ambient air after the plasma treatment. The TSEE glow curve (298–623 K) exhibited broad emission peaks at ∼373 and ∼473 K, and an increase in the intensity above 573 K. A theoretical analysis revealed that the glow curves were composed of four peaks except for the increase above 573 K, where each peak had a different trap depth, but almost the same electron affinity. The resolved two peaks in the lower temperature region increased compared to those in the higher temperature region with an increase in the O1s/Si2p ratio and also in the Si2p (oxide)/Si2p (substrate) ratio. The relationship of the surface chemical structure to the resolved four peaks is considered.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.353993
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  • 10
    Electronic Resource
    Electronic Resource
    Substitution effect of Y3+ with Ca2+ in YBa2Cu3O7−δ (abstract) : 35th annual conference on magnetism and magnetic materials (1991)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 69 (1991), S. 5391-5391 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The oxide superconductor YBa2Cu3O7−δ is known to have a rather free entrance of oxygen into the CuO chain between the BaO layers, and the oxygen deficiency δ is closely related with the critical temperature Tc. (1) When Y3+ site is substituted with Ca2+, the position of the oxygen vacancy is not on the Cu–O plane, but on the CuO chain as well as in the case of YBa2Cu3O7−δ. (2) When this substitution is done, electric neutrality is kept by the release of a half O2− for one Y3+ substitution with one Ca2+. (3) Therefore, the concentration of the positive hole is constant for this substitution, and Tc of the system is kept at the rather high temperature of about 86 K. (4) The relation between Tc and the hole concentration is in good agreement with the non-Ca2+ containing YBCO, and it can be said as a conclusion that the substitution of Y3+ with Ca2+ does not give any effect on the mechanism of the superconductivity of this system. (5) The crystallinity of the system is improved by the substitution to be better sintered and to have more narrow width of the critical temperature.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.348014
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