Showing papers by "Tokyo Institute of Technology published in 1986"
TL;DR: In this article, the electronic dipole moment and its polarization dependence are analyzed, and it is shown that the gain becomes maximum when the electric field of light is parallel to the longest side of the quantum box.
Abstract: Gain and threshold current density are analyzed for quantum-box lasers where electrons are confined in quantum well three-dimensionally, based on the density-matrix theory of semiconductor lasers with relaxation broadening. The electronic dipole moment and its polarization dependence are first analyzed, and it is shown that the gain becomes maximum when the electric field of light is parallel to the longest side of the quantum box. Calculated gain is about 10 times that of bulk crystal for 100 A × 100 A × 100 A GaAs/Ga 0.8 Al 0.2 As quantum box, and 15 times for Ga 0.47 In 0.53 As/InP quantum box with the same size, respectively. The threshold current density are 45 A/cm2and 62 A/cm2for GRINSCH GaAs/(Ga 0.8 Al 0.2 As-Ga 0.4 Al 0.6 As) and Ga 0.47 In 0.53 As/(Ga 0.28 In 0.72 As 0.6 P 0.4 -InP), respectively, where for the GaInAs/ GaInAsP/InP system the intervalence band absorption and nonradiative recombinations have been assumed to be the same as those obtained for bulk crystals experimentally. These results show the possibility of remarkable reduction in the laser threshold by the quantum-box structures.
1,020 citations
TL;DR: The suggested method is applied for the modelling and control of a multilayer incinerator and the designed fuzzy controller is tested by computer simulation using the identified process model.
386 citations
TL;DR: In this paper, the mechanism of photocatalytic decomposition of H2O into H2 and O2 over NiO and SrTiO3 powder was studied on the basis of the structure of the catalyst.
369 citations
TL;DR: The structure of NiO-SrTiO/sub 3/ powder has been studied by spectroscopic methods such as SEM, TEM, EXAFS, XANES, and XPS as mentioned in this paper.
Abstract: The structure of NiO-SrTiO/sub 3/ powder, which is a photocatalyst for the decomposition of water into H/sub 2/ and O/sub 2/, has been studied by spectroscopic methods such as SEM, TEM, EXAFS, XANES, and XPS. It has been clearly shown that the active catalyst has a peculiar structure; that is, nickel metal exists at the interface of NiO and SrTiO/sub 3/. The surface of NiO changes further into Ni(OH)/sub 2/ during the photocatalytic reaction in water. 31 references, 7 figures, 2 tables.
343 citations
324 citations
TL;DR: In this article, active and selective catalysts for oxidative coupling of methane were tested over many metal oxides (30 oxides) under the experimental conditions chosen (T = 973 K, PO2 = 0.4 kPa, PCH4 = 18.2 kPa and PHe = 82.7 kPa).
314 citations
TL;DR: In this article, the significance of possible influential factors with the use of the experimental design method was examined with the help of laboratory experiments, including surface roughness of steel, 50 percent diameter of sand, sand type, test type (simple shear and shear box), and uniformity coefficient of sand.
306 citations
TL;DR: In this article, the authors studied the transformation of propane into aromatic hydrocarbons over H-ZSM-5 and Ga-exchanged Zeolite zeolites.
303 citations
TL;DR: In this paper, a series of laboratory tests are carried out on the friction between steel and air-dried sands with a simple shear apparatus, and the significance of factors on the frictional coefficient are examined with the use of the experimental design method by orthogonal array table.
299 citations
TL;DR: A series of periodic increases in intracellular free calcium concentration ([Ca2+]i) occurred upon fertilization in golden hamster eggs, and the spatial distribution of the Ca2+ transients was investigated in single zona-free, aequorin-injected eggs, inseminated by single sperm.
298 citations
TL;DR: Two kinds of xerogels were prepared by slow and rapid hydrolyses of tetraethoxysilane and aluminum nitrate nonahydrate dissolved in ethanol as discussed by the authors.
Abstract: Two kinds of xerogels were prepared by the slow and rapid hydrolyses of tetraethoxysilane and aluminum nitrate nonahydrate dissolved in ethanol. Xerogels prepared by slow hydrolysis crystallized mullite directly from the amorphous state on firing whereas those formed by rapid hydrolysis crystallized a spinel phase before mullite formation. The composition of the spinel phase was characterized by various methods to be near SiO2·6Al2O3. The process of mullite formation is discussed in relation to the structures of the starting materials.
TL;DR: In this article, the affine Kac-Moody algebra for SU(2)×SU(2), for general r-dimensional torus, is found to be an unstable saddle point.
Abstract: Computation of the one-loop vacuum energy is attempted for closed bosonic string compactified on various tori. Modular invariance of the one-loop vacuum energy is shown. The divergent tachyon contribution forces us to employ a subtraction prescription. For one-dimensional torus, the affine Kac-Moody algebra for SU(2)×SU(2) is realized at the absolute minimum of the vacuum energy. For general r-dimensional torus, the algebra for [SU(2)×SU(2)]^r is found to be an unstable saddle point. A detailed study of r=2 case shows that SU(3)×SU(3) has the lowest vacuum energy.
TL;DR: In this paper, a geometric-progression (G-P) method formula, Br = 1 + (B − 1) · (Kx − 1)/(K − 1), accurately represents the buildup factor data as a function of distance for the following reasons:
Abstract: A geometric-progression (G-P) method formula, Br = 1 + (B − 1) · (Kx − 1)/(K − 1), accurately represents the buildup factor data as a function of distance for the following reasons:1. The value of ...
TL;DR: Modified hydrolytic enzymes catalysed the reverse reaction of hydrolysis in organic solvents: formation of acid—amide bonds by modified chymotrypsin, and ester synthesis and esters exchange reactions by modified lipase.
01 Jun 1986
TL;DR: An object-oriented computation model is presented which is designed for modelling and describing a wide variety of concurrent systems and an overview of a programming language called ABCL/1, whose semantics faithfully reflects this computation model, is presented.
Abstract: An object-oriented computation model is presented which is designed for modelling and describing a wide variety of concurrent systems. In this model, three types of message passing are incorporated. An overview of a programming language called ABCL/1, whose semantics faithfully reflects this computation model, is also presented. Using ABCL/1, a simple scheme of distributed problem solving is illustrated. Furthermore, we discuss the reply destination mechanism and its applications. A distributed “same fringe” algorithm is presented as an illustration of both the reply destination mechanism and the future type message passing which is one of the three message passing types in our computation model.
TL;DR: The 70% MeOH extract of Ganoderma lucidum had an inhibitory effect on angiotensin converting enzyme activity, and from this extract, five new triterpenes, named ganoderal A, ganoderols A and B, and ganodes K and S, were isolated.
Abstract: The 70% MeOH extract of Ganoderma lucidum had an inhibitory effect on angiotensin converting enzyme activity, and from this extract, five new triterpenes, named ganoderal A, ganoderols A and B, and ganoderic acids K and S, were isolated. Their structures were determined on the basis of spectral evidence.
TL;DR: Copper-catalyzed conjugate addition of the Grignard reagents in the presence of Me 3 SiCl and HMPA proceeds in much higher yield than the reaction of conventional organocopper reagents and shows very good regio-, stereo-, and chemoselectivities.
TL;DR: In this paper, the variation of magnetic susceptibility with martensitic and magnetic phase changes is examined in FeMnSi shape memory alloys using a Faraday type magnetic balance.
TL;DR: In this article, an AT-cut quartz piezoelectric crystal, oscillator and frequency counter was used to detect C. albicans in the range 106−5 × 108 cells cm−3.
TL;DR: Chlorotrimethylsilane, particularly if combined with hexamethylphosphoric triamide or 4-dimethylaminopyridine, strongly promote the conjugate addition of stoichiometric organocopper reagents.
TL;DR: In this article, a multiquantum barrier (MQB) was proposed and the reflectivity of an electron from the MQB is given theoretically and it is shown that the effective potential barrier of MQB can be higher than that of a classical bulk barrier.
Abstract: In the letter we propose a new multi-quantum structure, namely a multiquantum barrier (MQB). The reflectivity of an electron from the MQB is given theoretically and it is shown that the effective potential barrier of MQB can be higher than that of a classical bulk barrier.
TL;DR: In this article, the authors discuss the contrainte d'ecoulement et du module de Young for des alliages binaires a base de nickel a 77 K. Interpretation du durcissement par solution par la theorie des interactions elastiques.
Abstract: Mesure de la contrainte d'ecoulement et du module de Young pour des alliages binaires a base de nickel a 77 K. Determination de la vitesse de durcissement et de la vitesse de variation dans les constantes d'elasticite. Interpretation du durcissement par solution par la theorie des interactions elastiques. Comparaison avec le durcissement par solution solide de l'alliage Ni 3 Al
TL;DR: In this article, the authors studied the kinetic expression of ammonia synthesis over Ru powder, Ru/Al2O3, Ru-CsOH/Al 2O3 and Ru/MgO, and showed that the reaction is retarded by different adsorbed species.
TL;DR: In this paper, the authors proposed a method to analyze systems in a time scale which is varied depending on the state such as dt/d\tau = s(x) (where t and τ are the actual time scale and that of new one, respectively, and s is the function which they call time scaling function).
Abstract: In this note, we propose a method to analyze systems in a time scale which is varied depending on the state such as dt/d\tau = s(x) (where t and τ are the actual time scale and that of new one, respectively, and s(x) is the function which we call time scaling function). Analysis of the system in the new time scale τ enables us to investigate the intrinsic structure of the system. A linearization problem in the new time scale is formulated as wide-sense feedback equivalence and is solved. It is also shown that the time scaling function which makes the system linear is derived as the solution of differential equations.
TL;DR: In this article, an ultrasonic atomizer was used in the spray pyrolysis method to prepare fine, spherical and uniform ZnO particles, which had a mean particle size of 0.15 μm and had a very narrow particle size distribution.
Abstract: An ultrasonic atomizer was used in the spray pyrolysis method to prepare fine, spherical and uniform ZnO particles. Almost spherical particles were obtained successfully which had a mean particle size of 0.15 μm and had a very narrow particle size distribution. By using alcohol as the solvent, it was found that the particles do not have hollow shell layers which could usually be observed in the spray pyrolysis process by using water as the solvent. The morphology of the ZnO particles was strongly affected by the concentration of the starting solution.
TL;DR: In this paper, the photocatalytic hydrogen evolution from aqueous methanol solution over K4Nb6O17 and the photodecomposition of water into H2 and O2 over NiO-K 4Nb 6O17 powder are described.
Abstract: The photocatalytic hydrogen evolution from aqueous methanol solution over K4Nb6O17 and the photodecomposition of water into H2 and O2 over NiO–K4Nb6O17 powder are described.
TL;DR: In this article, the authors extended Newton and quasi-Newton methods to systems of PC 1 equations and established the quadratic convergence property of the extended Newton method and the Q-superlinear convergence property for the extended quasiNewton method.
Abstract: This paper extends Newton and quasi-Newton methods to systems of PC 1 equations and establishes the quadratic convergence property of the extended Newton method and the Q-superlinear convergence property of the extended quasi-Newton method.
TL;DR: In this article, the electrical conductivities of carbon-black-filled low-density polyethylene (LDPE), poly(methyl methacrylate) (PMMA), and poly(vinyl chloride)-vinyl acetate (PVC/VAc) copolymer were measured as functions of carbon content and melt viscosity of the matrix at the temperatures at which the composites were prepared.
Abstract: The electrical conductivities of carbon-black-filled low-density polyethylene (LDPE), poly(methyl methacrylate) (PMMA), and poly(vinyl chloride)-vinyl acetate (PVC/ VAc) copolymer were measured as functions of carbon content and melt viscosity of the matrix at the temperatures at which the composites were prepared. Sharp breaks in the relationship between the carbon filler content and the conductivity of composites were observed in all specimens at some content of the carbon filler. The conductivity jumps as much as 10 orders of magnitude at the break point. This phenomenon has been known as the “percolation threshold”. The critical carbon content corresponding to the break point
TL;DR: Proton-exchanged K4Nb6O17 showed high activity for H2 evolution from aqueous methanol solution without any assistance from other materials such as noble metals as mentioned in this paper.
Abstract: Proton-exchanged K4Nb6O17 showed high activity for H2 evolution from aqueous methanol solution without any assistance from other materials such as noble metals.
TL;DR: DA and 5‐HT in rat striatum may be preferentially deaminated by MAO‐A in vivo, and high‐dose treatment with clorgyline caused a significant decrease in levels of these three metabolites in both the perfusates and tissue homogenates.
Abstract: A dialysis cannula was implanted into rat striatum while the animals were anesthetized, and the area was perfused with Ringer solution while the animals were unanesthetized after at least 3 days following surgery. Concentrations of the metabolites of 3,4-dihydroxy-phenylethylamine (DA) and 5-hydroxytryptamine (5-HT) in the perfusate were determined by HPLC with electrochemical detection. Levels of the DA metabolites 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) in the perfusate significantly decreased after pargyline administration (50 mg/kg i.p.), which may inhibit not only monoamine oxidase (MAO)-B but also MAO-A in these high doses. The level of the 5-HT metabolite 5-hydroxyindoleacetic acid (5-HIAA) also decreased after pargyline treatment, although change in the relative level of 5-HIAA was less than that of DOPAC or HVA. To clarify the mechanisms for the metabolism of monoamines in rat striatum, highly specific MAO-A and -B inhibitors were used in the following experiments. Treatment with l-deprenyl (10 mg/kg), a specific inhibitor for MAO-B, did not cause any statistically significant change in DOPAC, HVA, and 5-HIAA levels. No significant change was found in rat striatal homogenates at 2 h after the same treatment with l-deprenyl. In contrast, low-dose treatment (1 mg/kg) with clorgyline, a specific inhibitor for MAO-A, caused a significant decrease in levels of these three metabolites in both the perfusates and tissue homogenates. In addition to the above three metabolites, the level of 3-methoxytyramine, which is an indicator of the amount of DA released, greatly increased after treatment with a low dose (1 mg/kg) of clorgyline. These results suggest that DA and 5-HT in rat striatum may be preferentially deaminated by MAO-A in vivo.