Direct observations of vortices in a high-Tc superconductor (La1-xSrx)2CuO4 by scanning SQUID microscopy

In order to investigate the behavior of vortices in high-T_c superconductors under low magnetic fields, we have performed scanning SQUID microscopy (SSM) on the ab-surfaces of (La_1-xSr_x)₂CuO₄ (LSCO) single crystals at low temperatures. The observed magnetic images clearly demonstrated vortices in units of K₀ (=hc/2e) below T_c. Vortices trapped inside the overdoped LSCO tended to be arranged in a one-dimensional manner, while those in optimally doped crystals were randomly distributed. From the variable-temperature SSM measurements, it was directly visualized that the normal state with regular magnetic-field distribution gradually changed into the inhomogeneous Meissner state, and finally vortices evolved, with decreasing temperature.     

Ueber die quantitative Bestimmung der Chinaalkaloide

Ohne Zusammenfassung     

Electron-spin relaxation phenomena in irradiated saccharides detected by pulsed electron paramagnetic resonance spectroscopy

We measured the relaxation times of radicals in saccharides upon γ-irradiation by means of X-band pulsed electron paramagnetic resonance (EPR) spectroscopy. We found that the field-swept signal of irradiated fructose by pulsed EPR showed three to four peaks depending on the dose. The relaxation times (T₁ and T₂) of the side peaks were longer than those of the main peak(s) from each irradiation, indicating that the radicals showing side peaks interact less with the surrounding environment. From relaxation time measurements of several irradiated saccharides, we conclude that T₂ relaxation times decrease with the increasing irradiation dose. In contrast, T₁ relaxation times show no correlation with the irradiation dose.     

Real-time observation on surface diffusion and molecular orientations for phthalocyanine thin films at nanometer spacial resolution

The morphology, electronic structure and ordering of the phthalocyanine thin films have been investigated at nanometer scale by photoelectron emission microscopy (PEEM) excited by polarized soft X-rays from synchrotron light source. The sample investigated was micropattern of silicon phthalocyanine deposited on gold surface. The incident angle dependences of the X-ray absorption near edge structure (XANES) spectra at the silicon K-edge revealed that the molecules of 5-layered films are lying nearly flat on the surface. Clear image of the micropattern was observed by PEEM, showing that the molecules are deposited via Volmer–Weber (VW) mode at room temperature. While, the surface diffusion was observed upon heating, and the micropattern image almost disappeared at 240 °C, representing the deposition mode changes from VW-mode to Frank–van der Merwe (FM)-one. On the basis of the photon-energy dependences of the brightnesses in the PEEM images, it was found that the molecules diffusing to the fresh gold surface rather stand-up at 240 °C. The observed changes in the molecular orientations at nanometer domains are discussed on the basis of the strengths of the molecule–molecule and molecule–surface interactions.     

The effect of water immersion on short-latency somatosensory evoked potentials in human

Background  

Water immersion therapy is used to treat a variety of cardiovascular, respiratory, and orthopedic conditions. It can also benefit some neurological patients, although little is known about the effects of water immersion on neural activity, including somatosensory processing. To this end, we examined the effect of water immersion on short-latency somatosensory evoked potentials (SEPs) elicited by median nerve stimuli. Short-latency SEP recordings were obtained for ten healthy male volunteers at rest in or out of water at 30°C. Recordings were obtained from nine scalp electrodes according to the 10-20 system. The right median nerve at the wrist was electrically stimulated with the stimulus duration of 0.2 ms at 3 Hz. The intensity of the stimulus was fixed at approximately three times the sensory threshold.     

Free radicals in irradiated wheat flour detected by electron spin resonance

By electron spin resonance (ESR) spectroscopy, we revealed free radicals in wheat flour before and after γ-ray inrradiation and their thermal behavior during heat treatment. The ESR spectrum of wheat flour before irradiation consists of a sextet centered atg=2.0 and a singlet signal at the sameg-value position. The first one is attributable to a signal with hyperfine (hf) interactions of Mn²⁺ ion (hf constant, 7.4 mT). The second signal originates from the carbon-centered radical. Upon γ-ray irradiation, however, a new signal with two triplet lines at the low- and high-field ends was detected on the Mn²⁺ sextet lines. We analyzed the triplet ESR lines as due to powder spectra (rhombicg-tensor symmetry) with nitrogen (¹⁴N) hf interactions. This indicates that a new organic radical was induced in the conjugated protein portion of wheat flour by γ-ray irradiation. The intensity of the organic free radical atg=2.0 detected in irradiated wheat flour increased monotonically under thermal treatment. The analysis of the time-dependent evolution process on the basis of the theory of transient phenomena as well as the nonlinear least-squares numerical method provided a unique time constant for the radical evolution in wheat flour during thermal treatment.     

Measurement and calculation of vapor–liquid equilibria for methanol + glycerol and ethanol + glycerol systems at 493–573 K

The vapor–liquid equilibria for methanol + glycerol and ethanol + glycerol systems were measured by a flow method at 493–573 K. The pressure conditions focused in this work were 3.03–11.02 MPa for methanol + glycerol system and 2.27–8.78 MPa for ethanol + glycerol system. The mole fractions of alcohol in vapor phase are close to unity at the pressures below 7.0 MPa for both systems. The pressures of liquid saturated lines of the liquid phase for methanol + glycerol and ethanol + glycerol systems are higher than that for the mixtures containing alcohol and biodiesel compound, methyl laurate or ethyl laurate.     

Substitution effect of Ba at the Sr sites in Sr(Fe,Re)O3

We study ?-meson production in nuclei to investigate the in-medium modification of the ?-meson spectral function at finite density. We consider ( ${\bar p},\phi$ ), (γ,p) and (π ^???, n) reactions to produce a ?-meson inside the nucleus and evaluate the effects of the medium modifications to reaction cross sections. The structures of the bound states, ?-mesic nuclei, are also studied. For strong absorptive interaction cases, we need to know the spectrum shape in a wide energy region to deduce the properties of ?.     

Crystal structure and lattice vibration of proton dissolved BaZr0.8Sc0.2O2.9

Heat capacity and neutron diffraction measurements were carried out to determine the location of protons in the crystal of proton conducting perovskite oxide BaZr_0.8Sc_0.2O_2.9. The heat capacity of proton- and deuteron-dissolved BaZr_0.8Sc_0.2O_2.9 showed a slight difference from that of the dry sample. It indicates that the librational motion of the OH(OD) group is not excited below room temperature. The neutron diffraction experiments on the deutron dissolved sample indicate that the deuteron exists near the 12h site.     

Phase transition in the mixed state of Bi2Sr2CaCu2Oy observed by local and macroscopic magnetometry

In Bi₂Sr₂CaCu₂O_y under magnetic fields along the c-axis, both the local and the macroscopic magnetization show clear steps indicating the first order phase transition (FOPT) in the vortex lattice (VL). Local measurements have revealed that the FOPT occurs from the center of the sample owing to the field inhomogeneity originated from the geometrical effect. The heights of the steps are strongly suppressed in local measurements by the demagnetization effect. With decreasing temperature, the irreversibility in the magnetization just below the step begins to increase and is smoothly connected to the second peak at low temperatures.