Showing papers by "Tohoku University published in 1976"
TL;DR: In this paper, the origin of persistent wave propagation through medium of reactwn-diffusion type 1s is explored based on a generalized time-dependent Ginzburg-Landau equation for a complex field W, namely, the equation derived previously in connection with the instability problems in nonlinear chemical kinetics.
Abstract: The origin of persistent wave propagation through medium of reactwn-diffusion type 1s explored. Our theory is based on a generalized time-dependent Ginzburg-Landau equation for a complex field W, namely, the equation derived previously in connection with the instability problems in nonlinear chemical kinetics. For slow variation of lV in space and tune the above equation is further reduced to a Navier-Stokes-like one for the phase gradient of TV. Under a certain condition, the "viscosity" coefficient becomes negative, and at the :-;arne time the temporally ordered state of uniform concentrations becomes unstable. In :-;uch a situation we find a particular solution corresponding to a propagating concentratiOn wave with a wave-source or sink
914 citations
TL;DR: In this article, the synthesis of continuous β-SiC fibres by a new process: the conversion of organometallic polymers to inorganic substances was studied, and the transformation process and the structure and mechanical properties of these fibres were studied.
Abstract: MUCH work has been done on preparing heat-resistant silicon carbide materials in fibrous form, since plastics or metals can be reinforced with them to obtain very heat-resistant material of great mechanical strength. SiC whiskers1 are, however, impractical because of their shortness (several mm), their non-uniform diameter and high cost of production. SiC-on-W (ref. 2) and SiC-on-C (ref. 3) filaments have been produced by chemical vapour methods. These coated filaments are more expensive, and the treatment for making such composite materials requires careful control. We report here on the synthesis of continuous β-SiC fibres by a new process: the conversion of organometallic polymers to inorganic substances. We have studied the transformation process and the structure and mechanical properties of these fibres.
464 citations
TL;DR: In this article, a conical spin structure whose screw axis coincides with the magnetic field direction and whose period is independent of the applied field is realized in magnetic fields greater than 4 kOe.
423 citations
TL;DR: Continuous Sic fibers with a tensile strength of 350 kg/mm2 and a Young's modulus of 30 tons/mm 2 were synthesized from an organometallic polymer as discussed by the authors.
Abstract: Continuous Sic fibers with a tensile strength of 350 kg/mm2 and a Young's modulus of 30 tons/mm2 were synthesized from an organometallic polymer. Continuous fibers were first obtained by heat-treating a polycarbosilane polymer which had been synthesized from dimethyldichlorosilane. The fiber, which contains ultrafine-grain crystallites of β-Sic, has no fiber texture measurable by X-ray diffraction and high-voltage electron microscopy.
385 citations
TL;DR: In this paper, two 1,2-disilacyclobutenes were prepared by the reaction of tetramethyldisilene with acetylenes, and several reactions of these new 1 2 disilacy clobutenets including oxidation, silylene insertion, iron carbonyl insertion, and addition to acetylene and dienes are reported.
345 citations
TL;DR: In this article, the metal 2p region spectra of mixed valence spinels, Co3O4, Fe3O 4, Mn 3O4 and related compounds were studied, and the satellite splittings of Co 2p 3 2 for the octahedrally coordinated cobaltous ions are 6.2 eV and those for the tetrahedrically coordinated ones are about 5.3 eV.
333 citations
326 citations
TL;DR: In this paper, a method is proposed to determine design forces for earthquake-resistant design of reinforced concrete structures using a modified linear model of the structure and recognizing the effect of energy dissipation in the nonlinear range of response.
Abstract: A method is proposed to determine design forces for earthquake-resistant design of reinforced concrete structures. The method uses a modified linear model of the structure and recognizes the effect of energy dissipation in the nonlinear range of response. Thus, the designer is provided with a procedure, at the level of linear spectral response analysis, with explicit options about the levels of inelastic response in different elements of a multistory reinforced concrete structure. The paper contains analytical tests of two-story to 10-story frames designed according to the proposed method.
311 citations
TL;DR: In this paper, an improved Dubinin-Astakhov adsorption equation was proposed to predict the isotherms of high pressure gases on MSC-5A.
271 citations
TL;DR: Using two identical hemispherical electron spectrometers with pre-retarding potential proportional to the energy analysed, precisely consistent values were obtained in this article, where the potential of the spectrometer was determined by the energy of the electron energy.
241 citations
01 May 1976
TL;DR: In this article, the authors applied X-ray photoelectron spectroscopy to study the composition of the passive film formed on an extremely corrosion resistant amorphous Fe-10.%Cr-13at.%P-7at.
TL;DR: In this article, the amorphous FeCrPC alloy was compared with the crystallized alloy having the same composition in potentiodynamic polarization curves and with an 18Cr8Ni stainless steel in current decay after abrading the specimens under anodic polarization.
TL;DR: E egg hatching was inhibited under certain environmental conditions for all species, although egg viability under such conditions varied from one species to another, and habitat separation of planktonic Acartia populations is discussed.
Abstract: The hatching of the eggs of 3 Acartia species (A. tonsa, A. clausi, and Acartia sp. I) spawned in the laboratory and the eggs of Acartia (species undetermined) isolated from natural bottom sediments was examined under various environmental conditions (temperature, salinity and temperature combinations, oxygen concentration, illumination, and the presence of bottom mud). The range of temperature and salinity in which eggs hatched differed from one species to another. Egg hatching was inhibited under certain environmental conditions for all species, although egg viability under such conditions varied from one species to another. In relation to these findings, habitat separation of planktonic Acartia populations and the role of dormant eggs during their seasonal absence in the plankton of Southern California coastal waters are discussed.
TL;DR: In this paper, an optically transparent semiconductor electrode whose surface was modified by the chemical binding of sensitising dyes was used to obtain a photocurrent as large as those previously observed at the unmodified electrodes in contact with the dye solutions.
Abstract: WE have developed a new type of electrochemical photocell, using an optically transparent semiconductor electrode whose surface was modified by the chemical binding of sensitising dyes. In spite of the absence of dye in the solution, a photocurrent, as large as those previously observed at the unmodified electrodes in contact with the dye solutions was obtained.
01 May 1976
TL;DR: In this paper, the existence of a suppression cut to the most obstructive spurious component consisting of the slower shear wave propagatating in a crystal has been experimentally found out for acousticsurface-wave propagation on LiNbO 3.
Abstract: The existence of a new suppression cut to the most obstructive spurious component consisting of the slower shear wave propagatating in a crystal has been experimentally found out for acousticsurface-wave propagation on LiNbO 3 . The plate is a 127.86° rotated Y-cut X-propagating plate and has a large electromechanical coupling coefficient.
TL;DR: In this article, the phase of the charge density wave in the Peierls-Frohlich state in the presence of impurity scattering has been analyzed and the frequency dependence of the electrical conductivity, σ(ω), is calculated at T = 0 K for weak pinning forces.
Abstract: The equation is derived which describes the dynamics of the phase of the charge density wave in the Peierls-Frohlich state in the presence of the impurity scattering. By use of the correlation function of the phase, the frequency dependence of the electrical conductivity, σ(ω), is calculated at T =0 K for the case of weak pinning forces. It is found that σ(ω) has a pronounced peak at a finite ω and that the theoretical results. If ω is replaced by ( T - T p ) where T p is the transition temperature the results are reminiscent of the conductivity in the region of fluctuations.
TL;DR: In this article, the microhardness of amorphous and crystalline chemical vapour-deposited silicon nitride (Pyrolytic-Si3N4) prepared under various deposition conditions using SiCl4, NH3 and H2 has been measured at room temperature.
Abstract: The Vickers microhardness (VMH) of amorphous and crystalline chemical vapour-deposited silicon nitride (Pyrolytic-Si3N4) prepared under various deposition conditions using SiCl4, NH3 and H2 has been measured at room temperature The apparent VMH of Py-Si3N4 increases with decreasing indenter load, following the Meyer equation For the amorphous Py-Si3N4, the VMH value at a load of 100 g ranges from 2200 to 3200 kg mm−2 depending upon deposition temperature (Tdep) and total gas pressure (Ptot) On the other hand, the VMH of the crystalline Py-Si3N4 does not depend uponTdep andPtot but is affected by the preferred orientation The hardness of the deposition surfaces with the (110), (210) and (222) orientations is 3800 kg mm−2, while that of the cross-section with the (001) orientation is 3100 kg mm−2 The hardness of the crystalline Py-Si3N4 is also affected by the grain size For the fine grained Py-Si3N4 (about 1μm), the VMH varies from 4600 to 5000 kg mm−2 The hardnesses of three types of Py-Si3N4 are discussed in comparison with those of other ceramics
TL;DR: Gel electrophoresis and gel electrofocusing in dissociating buffers indicate that the six conglycinins are isomers containing varying proportions of three kinds of subunits (alpha, alpha' and beta).
TL;DR: The binding energy of the peaks of Fe 2+ spectra are all located at binding energy 708·5 eV, and the width of the spectrum seems to be dependent on crystallinity.
TL;DR: In this paper, it was shown that Josephson lines can be interconnected in certain direct ways so that complete logic capability can be achieved with networks of Josephson line alone using fluxquantum vortices occurring in Josephson junctions of extended dimensions.
Abstract: New logic circuits are designed which employ as information bits the flux‐quantum vortices occurring in Josephson junctions of extended dimensions It is shown that Josephson lines can be interconnected in certain direct ways so that complete logic capability can be achieved with networks of Josephson lines alone
TL;DR: In this paper, the authors examined the onset times of three substorm events which were already defined by various methods other than the low-latitude Pi2 method and determined other evident substorm onsets are clearly determined with Pi2 onsets for all the three events by examining only the H -component of rapid-run magnetogram from a single lowlatitude station in the dark hemisphere.
TL;DR: Effects of 6 coronary vasodilators on the coronary blood flow and the contractile force of the ventricular muscle were examined simultaneously by injecting these drugs to the arterially blood-perfused canine papillary muscle preparation.
TL;DR: Results indicate that autoxidation of oxymyoglobin results in generation of superoxide radicals.
Abstract: Autoxidation of bovine oxymyoglobin to metmyoglobin induces co-oxidation of epinephrine to adrenochrome. This co-oxidation is markedly inhibited by superoxide dismutase [EC 1.15.1.1]. Electron transfer from oxymyoglobin to ferricytochrome c is partially inhibited by superoxide dismutase. These results indicate that autoxidation of oxymyoglobin results in generation of superoxide radicals. Autoxidation of oxymyoglobin is accelerated by superoxide dismutase and partially inhibited by catalase [EC 1.11.1.6].
TL;DR: In this article, the magnetic interactions in Heusler alloys Pd 2 MnSn and Ni 2 NMSn have been investigated using neutron spin wave scattering using a Heisenberg Hamiltonian where only Mn atoms have a localized moment.
Abstract: The magnetic interactions in Heusler alloys Pd 2 MnSn and Ni 2 MnSn have been investigated using neutron spin wave scattering. The spin wave dispersion relations along the [00ζ], [ζζ0] and [ζζζ] directions have been observed across the whole magnetic Brillouin zone. The results have been analyzed using a Heisenberg Hamiltonian where only Mn atoms have a localized moment. It has been found that the interactions between more than 6th neighbors should be taken into account to reproduce the observation. The exchange constants at large distances have an oscillatory character which can be interpreted by the s - d type interactions based on the nearly free electron model. However, the n . n . and n . n . n . interactions have signs opposite to those expected from the simple s - d model. The n . n . and n . n . n . exchange constants in Ni 2 MnSn ( T C =344 K) are larger than those in Pd 2 MnSn ( T C =189 K), although the oscillatory parts have nearly the same values for both alloys.
TL;DR: In this article, the Δ E effect due to the displacement of antiferromagnetic domain walls was investigated for polycrystalline γ Mn-Ni alloys with a temperature range between −180° and 250°C.
Abstract: Lattice parameters and elastic moduli of polycrystalline γ Mn alloys containing 12–40 at% Ni have been measured in a temperature range between –180° and 250°C. The face-centred cubic lattice undergoes a tetragonal distortion, either c / a 1, or an orthorhombic distortion at low temperatures. Both Young's modulus and shear modulus exhibit a step-type change at the Neel point and a broad minimum near the transition temperature of lattice distortion. The elastic behaviour is discussed on the basis of the so-called Δ E effect due to the displacement of antiferromagnetic domain walls. This effect may possibly be enhanced by the lattice softening in the γ Mn–Ni alloys.
TL;DR: It was concluded that Sendai virus with intact envelope does not exhibit hemolysis, while it has the potential activity to do so.