Showing papers by "Tokyo Institute of Technology published in 1972"
TL;DR: In this article, it was shown that ruthenium is remarkably promoted by the addition of alkali metal, particularly when supported by active carbon (AC) or alumina.
375 citations
TL;DR: A martensitic steel containing 1.13 wt. %C was tempered at 120°C for 1-100 days and the structure and morphology of precipitated carbide were studied by electron microscopy and selected area diffraction as discussed by the authors.
237 citations
TL;DR: In this article, a mixture of styrene and ethylbenzene was formed by alkylation of the methyl group of toluene on Na, K, Rb and Cs exchanged zeolites.
224 citations
TL;DR: Bovine taste buds bearing papillae exhibit high adenyl cyclase activity comparable to the activity found in the brain, while the tongue epithelium without taste buds exhibits much lower activity.
115 citations
112 citations
111 citations
TL;DR: In this paper, it was assumed that the post-oxidation reaction introduced a nitroxyl group smoothly and quantitatively at room temperature, and the electron spin behavior of the stable radical polymers were made in terms of elemental analyses, infrared, ultraviolet, and ESR spectroscopy.
Abstract: Polymers having stable nitroxyl free radicals, poly-4-methacryloylamino- and poly-4-methacryloyloxy-2,2,6,6-tetramethylpiperidine-1-oxyls, were synthesized from their precursor polymers by oxidizing them in a methanolic solution of hydrogen peroxide. The precursor polymers were prepared by radical polymerization of 4-methacryloyl-amino/oxy-2,2,6,6-tetramethylpiperidines in various solvents. These polymerizations in acetic acid were found to yield polymers of high molecular weight. The copolymers of the precursor monomers with styrene and methyl methacrylate were also prepared as precursor copolymers. These precursor polymers of a piperidine type were converted to the polymers having stable nitroxyl free radicals by the hydrogen peroxide method. In this report, it was assumed that the post-oxidation reaction introduced a nitroxyl group smoothly and quantitatively at room temperature. Elucidations of the stable radical formation and the electron spin behavior of the stable radical polymers were made in terms of elemental analyses, infrared, ultraviolet, and ESR spectroscopy.
110 citations
TL;DR: In this article, the authors give a complete answer to the latter problem: Vn--g~(z,z)>cB(z) with equality if and only if f2 is conformally equivalent to the unit disc less a (possible) closed set of inner capacity zero.
Abstract: Let K(z, z), cp(z) and c~(z) be the values of the Bergman kernel, the capacity, and the analytic capacity, on an open Riemann surface 12 (with respect to a fixed local parameter z). The following problem was raised by SARIO & OIKAWA [9]: Find a relation between the magnitudes of the quantities ]/~---g~(z, z), c a (z) and cg (z). As to ]/n--K-~(z, z) and ce (z), HEMAL obtained an answer for finite Riemann surfaces f2, namely that ] / ~ > c B ( z ) if f2 is not simply connected. 1 In the present paper, we shall give the following complete answer to the latter problem: Vn--g~(z,z)>cB(z) with equality if and only if either (i) 12e0o or (ii) f2 is conformally equivalent to the unit disc less a (possible) closed set of inner capacity zero. Concerning the problem for ]/n--K~(z, z) and ca(z), we are led to conjecture that ]/n--g-(~,(z,-z))> ca(z); this will be verified for doubly-connected regions in w 4. 6 2 By proving a new identity ~ log c a (z)= n K(z, z), we show that the conjecture
109 citations
TL;DR: In this article, surface-chemical criteria for the optimum adhesion are investigated and the minimum interfacial tension or the maximum wetting pressure is deduced from the published data and their own as a first approximation.
Abstract: According to Bikerman, who attributes failure in adhints to a weak boundary layer, it is almost impossible and meaningless to correlate adhesive strength to surface-chemical properties of adhints. Though his assertion seems to be confirmed by the recent studies of Schonhorn and his coworkers on the methods of CASING and TCR, not a few results have yet been accumulated, which show a close relation between them. In this paper surface-chemical criteria for the optimum adhesion are investigated and the minimum interfacial tension or the maximum wetting pressure is deduced from the published data and our own as a first approximation. It is emphasized that, when critical surface tension γ c would be used as a measure of surface-chemical properties of solid, its variability according to liquid series (nonpolar, polar and hydrogen bonding liquids) should be carefully taken into consideration. The importance is shown for polyethylene and its fluorine substituted polymers, using newly measured contact angl...
101 citations
TL;DR: In this article, the microtacticity of polystyrene and poly-α-methylstyrene was determined from a high-resolution NMR spectra with proton spin decoupling and it was confirmed that the nuclear OVERHAUSER effect due to proton decoupled has little effect on the relative intensities of the peaks assigned to chemically equivalent carbons except for stereochemical configuration.
Abstract: The carbon-13 high resolution nuclear magnetic resonance spectra with proton spin decoupling of polystyrene and poly-α-methylstyrene were measured. The spectra clearly split corresponding to triad, tetrad, and partially pentad placements, and these peaks were tentatively assigned. By comparison of the triad tacticity of poly-α-methylstyrene determined from carbon-13 spectra with that from proton spectra, it was confirmed that the nuclear OVERHAUSER effect due to proton decoupling has little effect on the relative intensities of the peaks assigned to chemically equivalent carbons except for stereochemical configuration.
The stereospecific polymerization mechanisms are discussed on the basis of the microtacticity determined from carbon-13 spectra. As a result, it is concluded that poly-α-methylstyrene polymerized with cationic and anionic catalysts can be described by BERNOULLIAN statistics, while the atactic polystyrene does not obey BERNOULLIAN but first or second order MARKOVIAN statistics.
Hochaufgeloste 13C-NMR-Spektren von Polystyrol und Poly-α-methylstyrol werden unter Bedingung der 1H-Spinentkopplung aufgenommen. Die Spektren zeigen klare Aufspaltungen, die den Triaden, Tetraden und teilweise den Pentaden entsprechen; die verschiedenen Signale werden versuchsweise zugeordnet. Durch Vergleich der Triaden-Taktizitaten von Poly-α-methylstyrol auf Grund der 13C-NMR-Spektren mit den Protonen-Spektren konnte gezeigt werden, das der OVERHAUSER-Effekt die relativen Intensitaten der Signale von chemisch aquivalenten Kohlenstoffatomen nur wenig beeinflust, mit Ausnahme bei der stereochemischen Konfiguration.
Die Mechanismen der stereospezifischen Polymerisation werden auf der Grundlage der durch 13C-NMR bestimmten Mikrotaktizitat diskutiert. Die kationische und die anionische Polymerisation von α-Methylstyrol kann durch die BERNOULLI-Statistik beschrieben werden, wogegen das ataktische Polystyrol der MARKOV-Statistik gehorcht.
83 citations
TL;DR: In this paper, the specific heat of NaNO 2 was measured as a function of temperature near its antiferroelectric-to-paraelectric phase transition point (T N ).
TL;DR: Box's Complex method, is used to solve an actual example amenable to the integrated approach, and it is shown that one of the alternative streams can be eliminated to give the optimal synthesis.
TL;DR: It is proposed that bitter taste is induced by penetration of bitter compounds into the non-polar region of the lipid layer of the gustatory receptor membrane.
TL;DR: In this article, the authors analyzed the 48 Ca (τ, t′) 48 Sc reaction by taking into account the twice single nucleon transfer process in which α-particle is formed as an intermediate state.
TL;DR: The effect of bitter compounds on the activity of phosphodiesterase in bovine taste papillae was examined and it was found that all the bitter compounds examined in the present study inhibit the phosphodiesters.
TL;DR: In this article, an analytical discussion of the mode property and the scattering loss of a two-dimensional dielectric waveguide with gradual refractive-index distribution in the transverse direction is presented.
Abstract: An analytical discussion of the mode property and the scattering loss of a two-dimensional dielectric waveguide with gradual refractive-index distribution in the transverse direction is presented. To describe scattering loss, a transverse correlation as well as an axial correlation of the irregular variation of the refractive index have been used. The field distribution, the group delay, and the maximum film thickness of a single-mode waveguide scarcely depends on the shape of the distribution. The maximum value of the film thickness in the single-mode transmission region optimizes the scattering loss and the energy confinement. The scattering loss of a waveguide with a gradual index distribution is smaller than that of a three-layer waveguide when the transverse correlation is small, but it is not much altered when the transverse correlation is large.
TL;DR: A series of monoalkylchromium complexes, RCrCl 2 (THF) 3 where R = methyl, ethyl, n-propyl and isobutyl and THF = tetrahydrofuran, have been prepared by reactions of chromium trichloride with organoaluminum compounds as mentioned in this paper.
TL;DR: This work has examined the effect of various odorants on lipid monolayers from olfactory epithelium and proposed a theory for the mechanism ofOlfactory reception, which suggests that the interaction of odorant molecules with the lipid layer of the ofactory receptor membrane is important in olf factory reception.
Abstract: PLASMA membranes isolated from bovine olfactory epithelium containing large numbers of olfactory receptors cells are characterized bya high lipid, and especially phospholipid, content1. Odorant molecules are lipoid-soluble, and so this suggests that the interaction of odorant molecules with the lipid layer of the olfactory receptor membrane is important in olfactory reception. We have therefore examined the effect of various odorants on lipid monolayers from olfactory epithelium and propose a theory for the mechanism of olfactory reception.
TL;DR: In this paper, single crystals of Cr 3 Te 4 with the pseudo-NiAs type structure have been made by chemical transport method in order to investigate the anomaly below 80 K. But on contrary to his result, the easy axis of the moment is parallel to the c-axis in the whole ferromagnetic region and antiferromagnetic order appears only in the c -plane.
Abstract: Single crystals of Cr 3 Te 4 with the pseudo-NiAs type structure have been made by chemical transport method in order to investigate the anomaly below 80 K. The saturation moment at 4.2 K is equal to 1.79±0.03 µ B per Cr 1- x Te (x=0.25), and the Curie temperature is 316 K. The magnetization only in the direction to the a -axis shows the anomaly that the saturation field increases abruptly below 80 K, which corresponds to the Neel point proposed by Andresen. But on the contrary to his result, the easy axis of the moment is parallel to the c -axis in the whole ferromagnetic region and antiferromagnetic order appears only in the c -plane. By a spin echo method, two nuclear magnetic resonance absorption lines of Cr 53 -nuclei are observed at 45.3 and 57.5 MHz at 4.2 K. The resonance frequencies increase remarkably below 80 K. This fact may support subsidiarily the existence of the antiferromagnetic order below 80 K.
TL;DR: In this article, the vibration-rotation bands (Meinel bands) of the ground electronic state of OH have been observed in the chemiluminescent gas phase reactions of ozone with ethylene, propylene, 1-butene, cis -2 -butene and tetramethylethylene at total pressures of about 3 torr at room temperature.
TL;DR: In this paper, the authors compared three light source models, i.e., radial, specular, and diffuse line source, for light intensity profile, overall rate of reaction, and radial scale-up ratio of annular photochemical reactors, with the assumptions of constant absorption coefficient and constant quantum efficiency.
Abstract: Three light source models, i.e., radial, specular, and diffuse line source models, are compared for light intensity profile, overall rate of reaction, and radial scale-up ratio of annular photochemical reactors, with the assumptions of constant absorption coefficient and constant quantum efficiency. The necessary condition for the radial light model to hold is that, when the ratio of inner radius to height of the reactor m, is 0.1, that of outer radius to inner radius ρ should be less than 3, and that when m is larger ρ should be close to 1. Published reaction data are analyzed according to this condition.
TL;DR: In this paper, the optical gain and spectral response of heterojunction phototransistors with wide-gap emitters have been examined theoretically in idealized cases, and it was shown that the optical gains are closely related to the current gain in the common-emitter configuration β of a heter-junction transistor.
Abstract: The optical gain and spectral response of heterojunction phototransistors with wide-gap emitters have been examined theoretically in idealized cases. The optical gain is found to be closely related to the current gain in the common-emitter configuration β of a heterojunction transistor. Because of Kroemer's factor, the injection efficiency of the emitter junction is very high, resulting in a high β or a large optical gain. However, β or the optical gain is limited by the base transport efficiency when the injection efficiency is extremely high. From the analyses, the optical gains and spectral responses of an n.GaAs-p. Ge-n.Ge heterojunction phototransistor and n-p-n homojunction phototransistors of GaAs and of Ge are numerically computed. It becomes evident that the heterojunction phototransistor has a higher optical gain and a wider spectral response ( \sim5 \times 10^{5} at wavelengths ranging from 0.9 to 1.5 µm) than either of the homojunction phototransistors.
TL;DR: The complexes [RuH2(PPh3)4] and [RhH 2(CO2)6(PhMe)], respectively, react (reversibly) with carbon dioxide to give [Ru(OOCH)H(PPH3)3(PhME)], [Rh2H2CO2)(PPh 3)6 (PhMe)] as discussed by the authors.
TL;DR: In this paper, the authors studied the texture and crystallization properties of copolymers of E and Vinyl Acetate (VAc) as a function of their composition and the crystallization temperature.
Abstract: It may be anticipated that uncrystallizable units, if introduced randomely into a crystallizable polymer chain, might strongly prohibit the chain folding and enhance intermolecular crystallization, which will give rise to the fringed micelle structure. In anticipation of this, crystallization and resultant texture were studied for random copolymers of ethylene (E) and vinyl acetate (VAc) as functions of composition and crystallization temperature. Crystallization was carried out isothermally from solution as well as from melt. DTA melting behavior of the melt-crystallized samples revealed that two types of crystals with different melting temperatures were formed during the isothermal crystallization of the copolymers. Since the height of the peak appearing at the higher temperature T1 decreased and that at the lower temperature T2 increased with the increasing VAc content and crystallization temperature, the former peak may be assigned to the chain folded crystals and the latter to the bundle-like crystals. In other words, the transition from the chain folding crystallization to the bundle-like crystallization did not occur sharply at a given composition as expected but the two types of crystallization coexist in a rather wide range of compositions, depending on the crystallization temperature.
It became also apparent that molecular fractionation occurred during the isothermal crystallization with respect to the composition of the copolymer. Electron microscopy could not confirm the existence of the bundle-like crystals, probably due to the fact that the individual bundle-like crystal was not large enough to be distinguished from much larger chain-folded lamellae with more definite shapes. On the other hand, solution grown crystals gave a single melting peak and a single X-ray long spacing, suggesting only the chain folding crystallization occurred in the whole range of compositions studied. Molecular fractionation was again evident and the material left uncrystallized in the solution increased with the VAc content. These results may imply that the intermolecular bundle-like crystallization depends strongly on the probability of finding other chain molecules around a given molecule. The X-ray crystallinity as well as the heat of fusion measured suggest that the thickness of the amorphous surface layer (loose loops) of the solution grown crystals increases with the VAc content.
Es ist zu erwarten, das die Kettenfaltung stark behindert wird, wenn unkristallisierbare Einheiten statistisch in eine kristallisierbare Polymerkette eingebaut werden, und das stattdessen eine intermolekulare Kristallisation bevorzugt wird, die zu einer „Fransen-Micellen-Struktur” fuhrt. Im Hinblick darauf wurde die Kristallisation und die daraus entstehende Textur fur statistische Copolymere des Athylens (E) und des Vinylacetats (VAc) in Abhangigkeit von Zusammensetzung und Kristallisationstemperatur untersucht. Die Kristallisation wurde isotherm sowohl aus der Losung wie auch aus der Schmelze durchgefuhrt. Das DTA-Schmelzverhalten der schmelzkristallisierten Proben zeigte, das zwei Kristalltypen mit verschiedenen Schmelztemperaturen wahrend der isothermen Kristallisation der Copolymeren gebildet wurden. Da das bei der hoheren Temperatur T1 gelegene endotherme Maximum mit zunehmendem VAc-Gehalt und mit steigender Kristallisationstemperatur abnahm, wahrend das bei der niedrigeren Temperatur T2 gelegene zunahm, darf T1 den kettengefalteten Kristallen und T2 den bundelahnlichen Kristallen zugeordnet werden. Dies heist mit anderen Worten, das der Ubergang von Kristallen mit gefalteten Ketten zur Bildung von bundelahnlichen Kristallen nicht, wie erwartet, plotzlich bei einer gegebenen Zusammensetzung auftritt, sondern das beide Typen von Kristallen uber einen ziemlich weiten Bereich der Zusammensetzung gleichzeitig existieren konnen.
Offensichtlich trat eine molekulare Fraktionierung bezuglich des Copolymergehaltes wahrend der isothermen Kristallisation ein. Es ist jedoch nicht gelungen, die bundelahnlichen Kristalle elektronenmikroskopisch nachzuweisen. Dies ist wahrscheinlich dadurch bedingt, das die einzelnen Bundelkristalle nicht gros genug waren, um sie von den viel groseren, kettengefalteten Kristallen mit ihrer besser ausgepragten Gestalt zu unterscheiden. Andererseits wurde bei losungskristallisierten Proben ein einzelner Schmelzpeak und eine einzige rontgenographische Langperiode gefunden. In diesem Fall srheint also die Kristallisation fur alle untersuchten Copolymeren nur durch Kettenfaltung zu erfolgen. Molekulare Fraktionierung hatte offensichtlich stattgefunden, und das in der Losung ubriggebliebene, unkristallisierte Material nahm mit steigendem VAc-Gehalt zu. Diese Ergebnisse konnten darauf hindeuten, das intermolekulare Kristallisation von der Wahrscheinlichkeit abhangt, mit der sich andere Kettenmolekule in der Umgebung eines Molekuls befinden. Die rontgenographisch gemessenen Kristallinitaten und auch die Werte der gemessenen Schmelzwarmen deuten darauf hin, das bei losungskristallisierten Proben die Dicke der amorphen Oberflachenschicht (lockere Srhlaufen) mit steigendern VAc-Gehalt zunimmt.
TL;DR: The synthesis of polystyrenes containing iodonium structure was investigated in this article, where phenyl polystyryliodonium bisulfate was quantitatively prepared from polystyrene iodosoacetate and benzene in the presence of conc sulfuric acid.
Abstract: The syntheses of polystyrenes containing iodonium structure were investigated It was found that phenyl polystyryliodonium bisulfate was quantitatively prepared from polystyrene iodosoacetate and benzene in the presence of conc sulfuric acid In a similar way, cross-linked phenyl- and thienyl-polystyryliodonium salts were synthesized Anion exchange reaction of phenyl polystyryliodonium bisulfate with sodium bromide and potassium thiocyanate was also studied
Die Synthese von Polystyrolen, die eine Jodoniumstruktur enthalten, wurde untersucht Es stellte sich dabei heraus, das Phenylpolystyroljodoniumbisulfat quantitativ aus Polystyroljodosoacetat und Benzol in Gegenwart von konzentrierter Schwefelsaure entsteht In ahnlicher Weise wurden vernetzte Phenyl- und Thienylpolystyroljodoniumsalze synthetisiert Die Anionenaustauschreaktion des Phenylpolystyroljodoniumsalzes wurde mit Natriumbromid und Kaliumrhodanat untersucht
TL;DR: In this article, the microwave spectrum of 3-methylthiophene was measured in the frequency region from 7.6 to 25 GHz and the barrier height was determined to be 740 cal/mole by assuming I α = 3.19 amu·A 2.
TL;DR: In this paper, the Nernstian plot of the e− (Pt)/esolv− system was linear and its slope was in agreement with the theoretical value for n=1.
TL;DR: In this article, the amount of acidic sites of a series of SnO 2 MoO 3 binary oxides was determined by n -butylamine titration and correlated to the catalytic activity to form acetone in the oxidation of propylene.
TL;DR: The phase diagram of the ternary system of Pb(Zn1/3Nb2/3)O3 and PbTiO3 was determined from structural and dielectric measurements as mentioned in this paper.
Abstract: Phase diagram of the ternary system of Pb(Zn1/3Nb2/3)O3–Ba(Zn1/3Nb2/3)O3–PbTiO3 is determined from structural and dielectric measurements. In the vicinity of Pb(Zn1/3Nb2/3)O3, two phases of perovskite (ferroelectric) and pyrochlore (non-ferroelectric) types are coexistent. The piezoelectric active part is found near the morphotropic (rhombohedral-tetragonal) phase boundary. The most active one is obtained for the composition of 0.8Pb(Zn1/3Nb2/3)O3–0.2Pb0.7Ba0.3(Zn0.1Nb0.2Ti0.7)O3, where the planar coupling factor reaches 0.44.