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  • 1
    Electronic Resource
    Electronic Resource
    Interrelationship between Ca^2^+-dependent phospholipid base-exchange reaction and phospholipase D-like activity in bovine retina
    Amsterdam : Elsevier
    Biochimica et Biophysica Acta (BBA)/Lipids and Lipid Metabolism 1003 (1989), S. 98-107 
    Details
    ISSN: 0005-2760
    Keywords: (Bovine retina) ; Base exchange reaction ; Phosphatidylcholine ; Phosphatidylethanolamine ; Phosphatidylserine ; Phospholipase D
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology , Medicine , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1016/0005-2760(89)90105-7
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  • 2
    Electronic Resource
    Electronic Resource
    A mechanism of photodissociation of diphenylmethane to a diphenylmethyl radical in solution (1998)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 109 (1998), S. 1359-1365 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The photodissociation of diphenylmethane by excitation to the S1 state at 266 nm in n-heptane solution is studied by nanosecond fluorescence and absorption spectroscopy. The formation of the diphenylmethyl radical is identified by its fluorescence, which is induced by excitation at 308 nm, and by its absorption. The growth rate of (3.7±0.4)×107 s−1 for the radical is equal to the decay rate of (3.8±0.4)×107 s−1 for the precursor fluorescence. The quantum yield of the radical is of the order of ∼10−3. Neither dissociation to the radical nor intersystem crossing to the T1 state is thermally activated, whereas activated internal conversion to the S0 state is observed. The formation of the radical depends linearly on the photolysis pulse fluence. The data are consistent with a mechanism that the molecule undergoes intersystem crossing from thermally equilibrated levels of the S1 state to vibrationally excited levels of the T1 state at which it dissociates in competition with vibrational relaxation. The mechanism is explained in terms of electronic coupling between the precursor and product states. The S1 state does not correlate adiabatically to the ground state of the C–H bond fission products, so intersystem crossing to the T1 state precedes dissociation. In the T1 state, avoided crossing between the ππ* (benzene) configuration and the σσ* (C–H) repulsive configuration results in the adiabatic potential energy surface which evolves to the ground state of the C–H bond fission products allowing rapid dissociation. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.476688
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  • 3
    Electronic Resource
    Electronic Resource
    Photodissociation of C–H and C–O bonds of p-methoxytoluene and p-methoxybenzyl alcohol in solution (1997)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 107 (1997), S. 9354-9360 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The photodissociation of p-methoxytoluene and p-methoxybenzyl alcohol at 266 nm in n-heptane solution is studied by nanosecond fluorescence and absorption spectroscopy. The formation of a p-methoxybenzyl radical is identified by its fluorescence which is induced by excitation at 308 nm. The yields of the radical are of the order of ∼10−3 for dissociation of p-methoxytoluene and p-methoxybenzyl alcohol. The growth rate of 1.5×108 s−1 for the radical is equal to the decay rate of (1.5±0.3)×108 s−1 for the precursor fluorescence in dissociation of p-methoxytoluene, whereas the growth rate of 〉1.0×109 s−1 for the radical is much faster than the decay rate of (1.8±0.3)×108 s−1 for the precursor fluorescence in dissociation of p-methoxybenzyl alcohol. The formation of the radical depends linearly on the photolysis pulse fluence for dissociation of p-methoxytoluene and p-methoxybenzyl alcohol. The data show existence of two distinct dissociation channels. p-Methoxytoluene dissociates from thermally equilibrated levels of the S1 state after vibrational relaxation, whereas p-methoxybenzyl alcohol dissociates from vibrationally excited levels of the S1 state in competition with vibrational relaxation. The difference of these channels is explained on a model of electronic coupling between the precursor and product states in the geometry where the C–H and C–O bonds are stretched in a plane perpendicular to the benzene rings. For p-methoxytoluene, the S1 state does not correlate adiabatically to the ground state of the C–H bond fission products, so intersystem crossing or internal conversion precedes dissociation. For p-methoxybenzyl alcohol, avoided crossing between the ππ* (benzene) configuration and the np(O)σ*(C–O) repulsive configuration results in the adiabatic potential-energy surface which evolves to the ground state of the C–O bond fission products allowing rapid dissociation. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.475232
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  • 4
    Electronic Resource
    Electronic Resource
    Experimental study of the bifurcation nature of the electrostatic potential of a toroidal helical plasma (2000)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Plasmas 7 (2000), S. 4152-4183 
    Details
    ISSN: 1089-7674
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The bifurcation nature of the electrostatic structure is studied in the toroidal helical plasma of the Compact Helical System (CHS) [K. Matsuoka et al., Proceedings of the 12th International Conference on Plasma Physics and Controlled Nuclear Fusion Research, Nice, 1988 (International Atomic Energy Agency, Vienna, 1989), Vol. 2, p. 411]. Observation of bifurcation-related phenomena is introduced, such as characteristic patterns of discrete potential profiles, and various patterns of self-sustained oscillations termed electric pulsation. Some patterns of the electrostatic structure are found to be quite important for fusion application owing to their association with transport barrier formation. It is confirmed, as is shown in several tokamak experiments, that the thermal transport barrier is linked with electrostatic structure through the radial electric field shear that can reduce the fluctuation resulting in anomalous transport. This article describes in detail spatio-temporal evolution during self-sustained oscillation, together with correlation between the radial electric field and other plasma parameters. An experimental survey to find dependence of the temporal and spatial patterns on plasma parameters is performed in order to understand systematically the bifurcation property of the toroidal helical plasma. The experimental results are compared with the neoclassical bifurcation property that is believed to explain the observed bifurcation property of the CHS plasmas. The present results show that the electrostatic property plays an essential role in the structural formation of toroidal helical plasmas, and demonstrate that toroidal plasma is an open system with a strong nonlinearity to provide a new attractive problem to be studied. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1290483
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  • 5
    Electronic Resource
    Electronic Resource
    Density fluctuations and confinement in the Nagoya Bumpy Torus (NBT-1M) (1991)
    New York, NY : American Institute of Physics (AIP)
    Physics of Fluids 3 (1991), S. 1052-1058 
    Details
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The stabilization of low-frequency density fluctuations is evidenced in the Nagoya Bumpy Torus (NBT-1M) [Plasma Physics and Controlled Nuclear Fusion Research (IAEA, Vienna, 1985), Vol. 2, p. 551] in the presence of microwave-heated hot-electron rings. Flute-type fluctuations, which are considered to be stabilized by the charge-uncovering effect of the rings, are found to cause large plasma losses, and to affect radial density profiles in the way that the lower fluctuation level yields the steeper density gradient. The particle confinement is, therefore, improved by the hot-electron rings to some extent, but is mainly determined by the plasma convection, which is expected from the discrepancy between density and potential profiles. It is also found that fluctuations in a toroidal plasma inside the ring grow when a weak negative ambipolar potential and a steep density gradient are formed, and are reduced to a low level when a deep potential well is achieved.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.859833
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  • 6
    Electronic Resource
    Electronic Resource
    Space-resolved measurement of internal magnetic field in a bumpy torus by Li0-beam probe spectroscopy (1985)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 56 (1985), S. 857-859 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A new method combining Li0-beam probing and spectroscopic techniques has been developed to measure local magnetic fields in a bumpy torus. A collimated thermal Li0 beam is injected into the plasma. The Zeeman pattern of the lithium resonance radiation (22S–22P, 6708 A(ring)) is observed with a Fabry–Perot interferometer. The strength of the local magnetic field is determined from the splitting between two π components of the 22S1/2–22P1/2 transition with the spatial resolution of about 7 mm. The magnetic fields from 2 to 4 kG were measured with accuracy of ±2%. This method is applicable to plasmas of a line-integrated electron density below 5×1012 cm−2.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1138072
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  • 7
    Electronic Resource
    Electronic Resource
    Space and time-resolved measurements of plasma density by a lithium neutral beam probe in NBT-1M (1985)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 56 (1985), S. 1050-1052 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A lithium neutral beam probe has been improved for space and time-resolved measurements of plasma density in NBT-1M. A lithium neutral beam (4 keV, 10–30 μA) is injected into the plasma and photon flux emitted from the injected lithium atoms by electron impact excitation is detected. This cross section is not sensitive to the electron temperature in a wide range (10 eV〈Te 〈200 eV) and the photon flux intensity is proportional to the electron density. Typical spatial and temporal resolutions are 1 cm and a few milliseconds, respectively. Beam attenuation is not severe for plasmas with n1〈1014 cm−2 unless the ion temperature is very high (Ti 〉1 keV), where the attenuation through charge-exchange process becomes dominant. This method is not influenced by the magnetic field and can be applied to plasmas in any magnetic field configuration.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1138265
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  • 8
    Electronic Resource
    Electronic Resource
    Reduction method for low-frequency noise of GaAs junction field-effect transistor at a cryogenic temperature (2002)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 80 (2002), S. 1844-1846 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A GaAs junction field-effect transistor (JFET) is a promising candidate for low-frequency, low-noise, and low-power cryogenic electronics to read out high-impedance photodetectors. We report on the spectral noise characteristics of a SONY n-type GaAs JFET, operating at the depression mode, at a cryogenic temperature of 4.2 K. If the GaAs JFET is turned on at 4.2 K, a random telegraph signal (RTS) is found to be the dominant noise source at low frequencies. However, the switching rate of RTS can be drastically reduced if the GaAs JFET is heated up to 55 K and cooled down again to 4.2 K while keeping the same drain current flow. We refer to this phenomenon as the thermal cure (TC). With TC, low-frequency noise can be reduced to below 1 μV/Hz1/2 at 1 Hz. The critical temperature for TC is found to be ∼35 K for our GaAs JFET. © 2002 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1461421
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  • 9
    Electronic Resource
    Electronic Resource
    Far-infrared laser oscillation from a very small p-Ge crystal under uniaxial stress (1999)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 74 (1999), S. 3432-3434 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We report on pulse laser oscillation from a p-Ge intervalence band (IVB) laser composed of a Ga-doped Ge crystal measuring about 1×1×5 mm3 which is a very small volume compared with those reported so far for shallow-acceptor-doped Ge. Laser oscillation is only achieved under uniaxial stresses greater than 1300 kg/cm2. We find that the optimum stress for lasing is around 3500–4100 kg/cm2 when the p-Ge IVB lasers are operated at liquid helium temperature. The minimum electric power needed for lasing is only 280 W at a peak period of pulse emission. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.124118
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  • 10
    Electronic Resource
    Electronic Resource
    Development of far-infrared Ge:Ga photoconductor having a longitudinal configuration (2000)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 77 (2000), S. 3099-3101 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: In order to efficiency obtain a two-dimensional (2D) image in the 3 THz range, it is important to develop a 2D far-infrared detector array. We have developed a gallium-doped germanium (Ge:Ga) far-infrared photoconductor that has a longitudinal configuration. This structure is suitable for a large format monolithic 2D array. In this letter, we show that a transparent electrode that is responsive in the far-infrared range can be formed by ion implantation, and this layer contributed to increasing quantum efficiency. We obtained a high responsivity (16.2 A/W) and good noise equivalent power (2.6×10−17 W/Hz1/2) of Ge:Ga photoconductor in longitudinal configuration by combination of ion-implanted layers and Ge:Ga bulk material. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1323742
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