Showing papers by "Tokyo Institute of Technology published in 1974"
TL;DR: In this article, a direct method of simultaneously polymerizing and forming acetylene monomer to produce uniformly thin films of polyacetylene was investigated in terms of catalyst system, catalyst concentration, and polymerization temperature.
Abstract: A direct method of simultaneously polymerizing and forming acetylene monomer to produce uniformly thin films of polyacetylene was investigated in terms of catalyst system, catalyst concentration, and polymerization temperature. The best catalyst was a Ti(OC4H9)4–Al(C2H5)3 system (Al/Ti = 3–4) and the critical concentration was 3 mmole/l. of Ti(OC4H9)4. Below the critical concentration, only a solid or a powder was obtained. The configuration of the polymers obtained depends strongly upon the polymerization temperature. Thus an all-cis polymer was obtained at temperatures lower than −78°C, whereas an all-trans polymer resulted at temperatures higher than 150°C. Observations either in an electron microscope by direct transmission or in a scanning electron microscope showed that the film is composed of an accumulation of fibrils about 200–300 A in width and of indefinite length.
918 citations
TL;DR: In this paper, the phase transition at 130°C is caused by condensation of the M 3 mode at the M point of the cubic Brillouin zone, while the one at 88°C results from condensing of the doubly degenerate R 25 -like mode (Z 9 mode) at the Z point of a tetragonal Brilloupin zone.
Abstract: Structural phase transitions in perovskite-type CsPbBr 3 have been investigated by neutron diffraction method. Phase transitions occur at 88°C and 130°C, which are respectively second and first order. The phase transition at 130°C is caused by condensation of the M 3 mode at the M point of the cubic Brillouin zone, while the one at 88°C results from condensation of the doubly degenerate R 25 -like mode ( Z 9 mode) at the Z point of the tetragonal Brillouin zone. Group theoretical considerations based on these results reveal that the crystal trans-forms from cubic perovskite structure (O h 1 - P m 3 m ) to tetragonal D 4h 5 - P 4/ m b m at 130°C and further to orthorhombic D 2h 16 - P m b n at 88°C. Possible atomic displacements induced at the phase transitions are obtained from the eigenvectors of the condensing modes.
204 citations
185 citations
183 citations
TL;DR: Graphite-like boron nitride was shock-compressed up to 550 kbar as discussed by the authors, and the X-ray diffraction pattern of the recovered specimen identified the wurtzite structure whose hexagonal cell dimensions were a 0 = 2.553±0.003 A, c 0 = 4.228± 0.004 A.
159 citations
TL;DR: In this paper, the authors determined the solubility of sulfur in volcanic rock melts (tholeiite basalt, hawaiite and rhyodacite from Hawaii) at various gas compositions and at 1250 and 1300°C and 1 atm total pressure.
158 citations
TL;DR: An in vitro study in which isolated prothoracic glands of the Bombyx silkworm were cultured has provided definite evidence that the protharacic gland is the site where molting hormone is synthesized.
Abstract: An in vitro study in which isolated prothoracic glands of the Bombyx silkworm were cultured has provided definite evidence that the prothoracic gland is the site where molting hormone is synthesized. The hormone behaved very similarly to free ecdysone on thin-layer chromatography. Analysis by liquid chromatography and mass fragmentography revealed that the hormone is identical with α-ecdysone.
156 citations
TL;DR: In this paper, the A-site deficient perovskite La 2 3 TiO 3 was synthesized under the controlled atmosphere of CO2-H2 mixed gas at 1350°C, and the structure was investigated by the powder X-ray diffraction method.
141 citations
TL;DR: In this paper, the decomposition of 2-propanol over alkali cation exchanged X and Y type zeolites was studied and the results showed that the K, Rb, and Cs zeolite had both acidic sites and basic sites.
120 citations
TL;DR: In this paper, a theoretical study has been made to predict overall thermal expansion characteristics of a two-phase material consisting of a matrix and aligned ellipsoidal inclusions, based on Eshelby's theory on the transformation problem; an approximate method is introduced to account for the effect of finite concentrations of the inclusions.
Abstract: A theoretical study has been made to predict overall thermal expansion characteristics of a two-phase material consisting of a matrix and aligned ellipsoidal inclusions. The calculation is based on Eshelby's theory on the transformation problem; an approximate method is Introduced to account for the effect of finite concentrations of the inclusions. The following two cases are treated: elastic matrix-elastic inclusions and elastoplastic matrix- elastic inclusions. The results are explicitly obtained when shapes of the inclusions are spherical, disc-shaped, and fiber-shaped. The calculated over all thermal expansion coefficient for the case of elastic matrix-elastic spheres agrees with Kerner's prediction.
115 citations
TL;DR: The graphitization of carbon fiber/glassy carbon composites was found to start at the boundary between the fibres and glassy carbon matrix, and to proceed into the matrix as discussed by the authors.
TL;DR: In this article, a bio-electrochemical sensor for hydrogen peroxide is described, which consists of two membranes, a catalase-collagen membrane and a teflon membrane.
TL;DR: The hydrodynamic instability theory is developed on the formation of rip-current and cuspidal coast in this article, and the most preferred wave length is shown to be about four times the distance from the shore to the breaker zone.
Abstract: The hydrodynamic instability theory is developed on the formation of rip-current and cuspidal coast. The most preferred wave length is shown to be about four times the distance from the shore to the breaker zone. Typical patterns of flow field and bottom configurations are represented. Finally, the theory is compared with field observations.
Journal Article•
TL;DR: In this paper, the performance of the GaAs MIS transistors was compared with the theoretical curves which were calculated by considering several limiting factors; bulk charges, a saturation velocity of carriers and series resistances.
Abstract: The alloying technique for source and drain n + regions and the chemical-vapor-deposited double layer films of Al 2 O 3 and SiO 2 were found to be useful for the realization of the inversion channel GaAs MIS transistors. This is because the alloying was carried out at much lower temperature than donor diffusion and the stability was remarkably improved by using the double layer above mentioned. The transistor had an effective mobility of 2240 cm 2 /V.sec, and the threshold voltage was controlled by changing the thickness ratio of the two films. The characteristics of the transistor were compared with the theoretical curves which were calculated by considering several limiting factors; bulk charges, a saturation velocity of carriers and series resistances. The fairly good agreement between the two was found. Some discrepancies, recognized in some cases, seemed to be attributable to some unknown parameters in the theory and to influences of interface states.
TL;DR: In this article, the N-phosphonium salts of pyridines were assumed to proceed via the n-photonium salts, similar to those obtained by the oxidation of phosphorus compounds with mercuric salts in pyridine, and the reactions were governed by the tertiary amine employed in the reaction.
01 Jan 1974
TL;DR: Character recognition is a categorizing process of unknown input pattern into one of known finite number of character categories and the similarity of input pattern is tested with the reference pattern of each category.
Abstract: Character recognition is a categorizing process of unknown input pattern into one of known finite number of character categories. Various practical methods of realizing this process has been devised. Pattern matching method is one of the most commonly used techniques in which the similarity of input pattern is tested with the reference pattern of each category.
TL;DR: A series of new compounds A Fe 2 O 4 (A = Ho, Er, Tm, Yb, and Lu) have been successfully synthesized under the lower oxygen partial pressures at 1200°C and their unit cell dimensions were determined as mentioned in this paper.
TL;DR: In this paper, microwave spectroscopic measurements on ethylene sulphide have been extended to allow a complete determination of substitution structure parameters, with the exception that the C-C distance is slightly shorter at 1.484 A.
01 Oct 1974-Metallurgical and Materials Transactions B-process Metallurgy and Materials Processing Science
TL;DR: In this article, an experimental procedure for measurement of the permeability of dissolved oxygen gas in liquid slag has been developed using an oxygen concentration cell, and the small amount of oxygen gas which penetrated through the liquid oxide from a pure oxygen compartment to a pure argon compartment was determined by the galvanic cell.
Abstract: An experimental procedure for measurement of the permeability of dissolved oxygen gas in liquid slag has been developed using an oxygen concentration cell. The small amount of oxygen gas which penetrated through the liquid oxide from a pure oxygen compartment to a pure argon compartment was determined by the galvanic cell. The permeabilities of oxygen through liquid PbO-SiO2 and FeO-PbO-SiO2 were found to be in the range 3 x 10-8 to 3 x 1O-7 moles/cm s. The permeabilities were little influenced by temperature but more influenced by the composition. In separate experiments, the oxygen pressure change at the bottom of a column of slag was detected by another galvanic cell. By this method, it is not necessary to quench the specimen to determine the concentration profile of dissolved oxygen and to determine its diffusivity. Liquid oxides in the PbO-SiO2, CaO-SiO2-Al2O3and FeO-PbO-SiO2 systems were studied. The oxygen diffusion coefficients (5 x 10-5 to 3 x 10-3 cm2/s) were found to increase with temperature for a fixed composition of slag, and with an increase of network-modifier oxide content at constant temperature. The solubility of oxygen gas in PbO-SiO2 melts was estimated to be 2 x 10-4 to 2 x 10-5 moles/cm3 from the determined diffusivities and permeabilities. The solubilities decreased with increasing temperature in the composition range studied. Physical solubilities of gases and metals in slags determined by other investigators are compared with the present results.
TL;DR: In this paper, the Raman spectra of the mono-negative ion of biphenyl in tetrahydrofuran solution were obtained by Ar+, He-Ne and Kr+ laser exciting lines.
TL;DR: The snake, in spite of its simple shape, can be considered to be a versatile robot having various functions, and its biomechanical study will be instructive to design a new snake-like vehicle.
Abstract: The snake, in spite of its simple shape, can be considered to be a versatile robot having various functions. The authors are greatly intrigued by this fact, and believe that its biomechanical study will be instructive to design a new snake-like vehicle.
TL;DR: In this paper, the ratios of fumarolic condensate, hot spring water and surface water collected from a volcanic island, Satsuma-Iwojima, were determined together with some of chemical components.
Abstract: D/H and 18O/16O ratios of fumarolic condensate, hot spring water and surface water collected from a volcanic island, Satsuma-Iwojima were determined together with some of chemical components. δD and δ18O of fumarolic condensates range from -27 to -17‰ (SMOW) and from +7.3 to +9.5‰ (SMOW), respectively. The high value of δ18O was concluded to be the result of thorough oxygen isotope exchange with ambient andesitic rocks. δD values are also higher than that of the local surface water, but we could not find a positive evidence that supports the assumption of mixing of the local surface water and sea water. On the basis of the relationship between the concentration of chemical components and isotope ratios of fumarolic condensates, it was concluded that water vapor and chemical components behave independently in an individual fumarole.
TL;DR: The relationship between the inhibition of the activity by p-chloromercuribenzoate and temperature may suggest that a thermal transition of the enzyme protein accompanies some structural change around sulfhydryl group.
TL;DR: The stiffness of the cell surface increased during the diaster stage, increased again, reached a maximum during cleavage and then diminished, in the eggs of Temnopleurus toreumaticus at 25.5 to 26.5 °C.
TL;DR: In this article, a bright nickel was passivated in the pH 8·39 boric acid-borate buffer solution, and the oxide formation reactions were mainly investigated by means of polarization experiments, alternating anodic and cathodic polarization, potential decay experiments and colorimetric analysis.
TL;DR: In this paper, a slag-lime pastes of low porosity (water/solid ratio of 0.20) were hydrated from 6 hours to 180 days at 20°C and the results of x-ray diffraction and SEM observations indicate only the formation of ill-cyrstallised hydration products.
TL;DR: In this paper, the carbon-13 chemical shifts of three arylmethyl carbanions were determined by changing solvents and counter ions and compared with those obtained from the 1H chemical shifts.
Abstract: Carbon-13 chemical shifts of three arylmethyl carbanions have been determined by changing solvents and counter ions. The charge distributions in the carbanions are discussed and compared with those obtained from the 1H chemical shifts.
TL;DR: In this paper, the crystal structure and precipitation mode of the carbide in a martensitic 0.45 wt%C steel tempered at 120 and 200°C have been studied by means of electron microscopy and selected area diffraction.
Abstract: Crystal structure and precipitation mode of the carbide in a martensitic 0.45 wt%C steel tempered at 120 and 200°C have been studied by means of electron microscopy and selected area diffraction. In both plate-like and lath martensites, the precipitated carbide is η-Fe2C like the previous case of high carbon steel(Acta Met.,20(1972),645). The crystal morphology and the orientation relationships between the carbide and the matrix are also the same. In general, the precipitation occurs along dislocations, but it has been found that grain boundary precipitation also takes place in the non-parallel lath region and that in fine grains in this region the carbide precipitation does not occur. Some discussions are given to the crystal structure and the precipitation mode of the carbide. (Received September 4,1973)