Search Results - (Author, Cooperation:M. Fujiwara)

2018-06-30

American Physical Society (APS)

0556-2813

1089-490X

Physics

Nuclear Structure

2018-06-21

Institute of Physics (IOP)

1367-2630

Physics

2018-07-06

The American Society for Pharmacology and Experimental Therapeutics (ASPET)

0090-9556

1521-009X

Chemistry and Pharmacology

Medicine

2011-09-10

American Association for the Advancement of Science (AAAS)

0036-8075

1095-9203

Biology

Chemistry and Pharmacology

Computer Science

Medicine

Natural Sciences in General

Physics

Adenosine Triphosphate/metabolism ; Animals ; Animals, Genetically Modified ; Caenorhabditis elegans ; Calcium/*analysis ; *Calcium Signaling ; *Directed Molecular Evolution ; Fluorescence ; Fluorescence Resonance Energy Transfer ; Green Fluorescent Proteins/*chemistry/genetics ; HeLa Cells ; Humans ; Luminescent Proteins/*chemistry/genetics ; Molecular Sequence Data ; Neurons/metabolism ; *Protein Engineering ; Rats ; Recombinant Fusion Proteins/*chemistry ; Spectrometry, Fluorescence ; Transfection

2018-05-25

American Physical Society (APS)

0031-9007

1079-7114

Physics

Atomic, Molecular, and Optical Physics

2011-07-26

Nature Publishing Group (NPG)

0028-0836

1476-4687

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

Animals ; Anthozoa/chemistry/*genetics/immunology/*physiology ; *Climate Change ; Coral Reefs ; Cyclohexylamines ; Cystathionine beta-Synthase/genetics ; Cysteine/biosynthesis ; DNA Damage/genetics/radiation effects ; Fossils ; Genome/*genetics ; Glycine/analogs & derivatives/biosynthesis ; Molecular Sequence Data ; Phylogeny ; Protein Structure, Tertiary ; Sea Anemones/genetics/immunology ; Symbiosis/genetics ; Ultraviolet Rays

0005-2760

(Bovine retina) ; Base exchange reaction ; Phosphatidylcholine ; Phosphatidylethanolamine ; Phosphatidylserine ; Phospholipase D

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Biology

Chemistry and Pharmacology

Medicine

Physics

Electronic Resource

2018-09-29

American Physical Society (APS)

1098-0121

1095-3795

Physics

Electronic structure and strongly correlated systems

1089-7674

AIP Digital Archive

Physics

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.

Electronic Resource

1077-3118

AIP Digital Archive

Physics

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.

Electronic Resource

1089-7623

AIP Digital Archive

Physics

Electrical Engineering, Measurement and Control Technology

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.

Electronic Resource

1089-7623

AIP Digital Archive

Physics

Electrical Engineering, Measurement and Control Technology

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.

Electronic Resource

1077-3118

AIP Digital Archive

Physics

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.

Electronic Resource

1077-3118

AIP Digital Archive

Physics

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.

Electronic Resource

1089-7666

AIP Digital Archive

Physics

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.

Electronic Resource

1089-7690

AIP Digital Archive

Physics

Chemistry and Pharmacology

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.

Electronic Resource

1089-7690

AIP Digital Archive

Physics

Chemistry and Pharmacology

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.

Electronic Resource

1095-8649

Blackwell Publishing Journal Backfiles 1879-2005

Biology

The day and night pattern of upstream and downstream dispersal of masu salmon fry of wild and domestic origin was compared in artificial channels (45 m long), for two ages of planting: unfed alevins and eyed eggs. Early dispersal was important for the wild stock (48–50%) compared with the domestic one (16–36%). More wild fry moved downstream than upstream, and more domestic fry dispersed upstream. Upstream movement in wild and domestic fry was more active by day than by night, except for wild fry planted as eyed eggs, where upstream migration was higher at night. In contrast, downstream movement in wild and domestic fry was more common by night than by day, but daylight catches were not negligible for the wild stock.

Electronic Resource

0003-2697

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Biology

Chemistry and Pharmacology

Electronic Resource

1398-9995

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Electronic Resource