Showing papers by "Tokyo Institute of Technology published in 1983"
TL;DR: A realistic fuzzy reasoning algorithm and a method to identify control rules from human operators actual control actions and the performance of the proposed algorithm is examined by applying it to water cleaning process control.
821 citations
TL;DR: In this article, a critical review of field performance of sandy soil deposits during past earthquakes was conducted with special emphasis being placed on Standard Penetration Test N-values and fines content.
331 citations
14 Apr 1983
TL;DR: This paper presents a new technique of cepstral analysis synthesis on theMel frequency scale, the log spectrum on the mel frequency scale (the mel log spectrum) is considered to be an effective representation of the spectral envelope of speech.
Abstract: This paper presents a new technique of cepstral analysis synthesis on the mel frequency scale, the log spectrum on the mel frequency scale (the mel log spectrum) is considered to be an effective representation of the spectral envelope of speech. This analysis synthesis system uses the mel log spectrum approximation (MLSA) filter which was devised for the cepstral synthesis on the mel frequency scale. The filter coefficients are easily obtained through a simple linear transform from the mel cepstrum defined as the Fourier cosine coefficients of the mel log spectral envelope of speech. The MLSA filter has a low coefficient sensitivity and a good coefficient quantization characteristics. The spectral distortion caused by interpolation of the filter parameters of two successive frames is small. Accordingly, the data rate of this system is very low. The same quality speech is synthesized at 60-70 % of data rates in the conventional cepstral vocoder or the LPC vocoder.
296 citations
TL;DR: In this article, a tetragonal ZrO2 powder was prepared by hydrothermal treatment at 100 MPa of amorphous hydrous zirconia with distilled water and LiCl and KBr solutions.
Abstract: Ultrafine tetragonal ZrO2 powder was prepared by hydrothermal treatment at 100 MPa of amorphous hydrous zirconia with distilled water and LiCl and KBr solutions. The resulting powder consisted of well-crystallized particles; at 200°C, the particle size was 16 nm and at 500°C, 30 nm. Under hydrothermal conditions tetragonal ZrO2 appears to crystallize topotactically on nuclei in the amorphous hydrous zirconia.
266 citations
TL;DR: In this paper, a reciprocating oscillatory turbulent flow in a rectangular duct is investigated experimentally by making use of a laser-Doppler velocimeter, hot-wire anemometers as well as electronic digital sampling and processing equipments.
Abstract: A reciprocating oscillatory turbulent flow in a rectangular duct is investigated experimentally by making use of a laser-Doppler velocimeter, hot-wire anemometers as well as electronic digital sampling and processing equipments.The profiles of the mean velocity, the turbulence intensities, the Reynolds stress and the turbulent-energy production rate are compared for the accelerating and decelerating phases.The characteristics of such a flow are quite different from wall turbulence which is steady in the mean. In the accelerating phase, turbulence is triggered by the shear instability at a slight distance from the wall but is suppressed and cannot develop. However, with the beginning of flow deceleration, turbulence grows explosively and violently and is maintained by the bursting type of motion.The turbulent-energy production becomes exceedingly high in the decelerating phase, but the turbulence is reduced to a very low level at the end of the decelerating phase and in the accelerating stage of reversal flow. Spectra and spatial correlations for the various phases are compared. The spectral decay in the high-frequency range for the decelerating phase with high turbulence is far steeper than that of Kolmogorov's −5/3 power law, indicating remarkably high energy dissipation by high-frequency turbulence.Notwithstanding the great difference between the ensemble-averaged characteristics of the oscillatory flow and those of steady wall turbulence, its basic processes such as ejection, sweep and interactions directed towards and away from the wall are the same as those of ‘steady’ wall turbulence.
264 citations
TL;DR: In this paper, a selective permeability of polymers derived by electrochemical polymerization from phenol and amino-aromatic compounds to the various oxidation-reduction species dissolved in the solution was investigated by means of hydrodynamic voltammetry at a rotating disk electrode.
228 citations
TL;DR: The phase diagram of the system ZrO2-CeO2 was investigated using hydrothermal techniques in this article, and the solubility limits of the tetragonal and cubic solid solutions are about 18 and 70 mol% CeO2, respectively, at 1400°C, and about 16 and 80 mol% CO 2 at 1200°C.
Abstract: The phase diagram of the system ZrO2-CeO2 was reinvestigated using hydrothermal techniques. Cubic, tetragonal, and monoclinic solid solutions are present in this system. The tetragonal solid solution decomposes to monoclinic and cubic solid solutions by a eutectoid reaction at 1050°±50°C. The solubility limits of the tetragonal and cubic solid solutions are about 18 and 70 mol% CeO2, respectively, at 1400°C, and about 16 and 80 mol% CeO2, respectively, at 1200°C. Solubility limits of the monoclinic and cubic solid solutions are about 1.5 and 88 mol% CeO2 at 1000°C, and 1.5 and 98 mol% CeO2 at 800°C, respectively. The compound Ce2Zr3O10 is not found in this system.
227 citations
TL;DR: In this article, a computer-aided design is described that makes it possible to reduce the internal impedance levels of branch line couplers so that they may be physically constructed by microstrip lines, where the Fletcher-Powell search method has been used to optimize the design.
Abstract: A computer-aided design is described that makes it possible to reduce the internal impedance levels of branch-line couplers so that they may be physically constructed by microstrip lines, where the Fletcher-Powell search method has been used to optimize the design. Because microstrip lines are severely restricted in their usable impedance range, the 3-dB couplers presented here should be useful for numerous balanced-type components such as balanced mixers. The validity of the design has been experimentally verified in the microwave and millimeter-wave region.
202 citations
TL;DR: In this paper, a small amount of Mn addition not only favorably affects sinterbility of ceramics but also advantageously heightens the unloaded Q. A value of Q higher than l04 is obtained in 10 GHz band.
Abstract: The present investigation relates ceramics with a temperature-stable high dielectric constant and low dielectric loss, suitable for use in dielectric resonators in an SHF band. A small amount of Mn addition not only favorably affects sinterbility of ceramics but also advantageously heightens the unloaded Q. A value of Q higher than l04 is obtained in 10 GHz band.
194 citations
TL;DR: In this paper, the empirical formula of gamma-ray buildup factors by a geometric-progression (G-P) method was modified by presenting the K parameter as a function of the penetrating distance from the source.
Abstract: The empirical formula of gamma-ray buildup factors by a geometric-progression (G-P) method was modified by presenting the K parameter as a function of the penetrating distance from the source. The ...
179 citations
TL;DR: In this paper, a demagnifying focusing mirror-monochromator optics has been designed and constructed for time-resolved X-ray diffraction studies of biological substances.
TL;DR: A method of constructing the mel-log spectrum approximation (MLSA) filter, which has a relatively simple structure and a low coefficient sensitivity, together with a design example of MLSA filter for speech synthesis.
Abstract: The spectral envelope of speech can be represented efficiently by the log magnitude spectrum on the nonlinear frequency scale, which is close to mel scale (called mel-log spectrum). the mel cepstrum defined by its Fourier coefficients is also considered to have a suitable property as the parameter to represent the spectral envelope. So far, no satisfactory filter has been reported for the synthesis approximating the mel-log spectrum. This paper presents a method of constructing the mel-log spectrum approximation (MLSA) filter, which has a relatively simple structure and a low coefficient sensitivity, together with a design example of MLSA filter for speech synthesis. the transfer function of MLSA filter is represented by Pade approximation, which approximates the exponential of the transfer function of the filter (so-called basic filter). Since the transfer function of the basic filter is represented by a polynomial with the transfer function of the first-order all-pass filter as the variable, it is necessary in the realization of the filter to delete from the feedback loop the path without a delay. By the construction method of MLSA filter shown in this paper, the path without delay can easily be deleted from the feedback loop in the MLSA filter. the obtained MLSA filter is of relatively simple structure and has low coefficient sensitivity. the quantization characteristics of the coefficient are also satisfactory.
TL;DR: A fundamental behavior of the CeO/sub 2/ in its reduction by hydrogen and carbon monoxide and in the oxidation by water and carbon dioxide is described in this article, where the effects of solid additives on the rates of reduction and oxidtion of the oxide are also described briefly.
TL;DR: In this article, the authors present a review of the dynamic single-mode (DSM) semiconductor laser in the wavelength of 1.5-1.6 µm.
Abstract: Recent progress in the dynamic single-mode (DSM) semiconductor lasers in the wavelength of 1.5-1.6\mu m are reviewed and the basic principle of DSM operation is given. Study of the DSM laser is originated for application to the wide-band optical-fiber communication in the lowest loss wavelength region of 1.5 to 1.65 μm. A DSM laser consists of a mode-selective resonator and a transverse-mode-controlled waveguide, such as the narrow-striped distributed-Bragg-reflector (DBR) laser, so as to maintain a fixed axial mode under the rapid direct modulation. The technology of monolithic integration for optical circuits is applied to realize some of DSM lasers. Structures, static and dynamic characteristics of lasing wavelength, output power, and reliability of the art DSM lasers are reviewed. The dynamic Spectral width of 0.3 nm, the output power of a few milliwatts, and the reliability over a few thousand hours are reported for experimental DSM lasers.
TL;DR: In this paper, the yield stress of nylon 6 (Ny6) composites filled with ultrafine and micron-sized (SiO2 and glass) particles was measured as a function of temperature, rate of strain, and filler content.
Abstract: The yield stress of nylon 6 (Ny6) composites filled with ultrafine and micron-sized (SiO2 and glass) particles was measured as a function of temperature, rate of strain, and filler content. The yield stress of the composites filled with ultrafine SiO2 particles increased with filler content and decreased with filler size, whereas for composites filled with glass particles, this relation was reversed. For ultrafine SiO2 filled composites, the tensile yield stress was found to be reducible with regard to temperature, rate of strain, and filler content. At a given filler content, composite curves were obtained for yield stress plotted against the logarithm of the strain rate. The Arrhenius plot of the shift factors for composing the strain rate-temperature master curve formed a single curve irrespective of the filler content and size. The curve comprised two linear regions with a break appearing at 110[ddot], corresponding to a transition of the matrix polymer. The master curves obtained for differe...
TL;DR: In this article, the anomalous magnetic moment of the muon (g − 2) μ imposes constraints on the masses and mixings of spin-zero leptons, gauge fermions, and Higgs Fermions.
TL;DR: For polypropylene composites filled with ultrafine or particles of the order of microns, (SiO2 and glass, respectively), yield stress was measured as functions of temperature, the rate of strain and filler content as mentioned in this paper.
Abstract: For polypropylene composites filled with ultrafine or particles of the order of microns, (SiO2 and glass, respectively), yield stress was measured as functions of temperature, the rate of strain and filler content. The yield stress of the composites filled with ultrafine particles increased with the filler content and decreased with the filler size, while for the composites filled with glass particles, these relations were reversed. For SiO2 filled composites, the tensile yield stress was found to be reducible with regard to temperature, the rate of strain and the filler content. The Arrhenius plot of the shift factors for composing the logarithmic strain rate — temperature master curve formed a single curve irrespective of the filler content and size. The curve comprised three linear regions with breaks appearing at 60 and 110° C, where the transition of the matrix polymer took place. The master curves obtained for different contents of a given size filler could be further reduced into a grand composite curve by shifting them along the axis of logarithmic strain rate, with the logarithmic second shift factors proportional to the square root of the volume fraction of the filler. The dependence of the filler volume fraction on the second shift factor was related to the dispersion state of fillers in PP matrix, namely, the promotion of the aggregation with filler content. The dependences of the yield stress on the filler volume fraction and size were explained by a modified equation based on the dispersion strength theory, with an aggregation parameter incorporated.
TL;DR: In this article, allyl enol carbonates, prepared from ketones or aldehydes by trapping their enolates with allyl chloroformate, to give α-allyl ketones and aldehides regioselectivity is catalyzed by palladium-phosphine complexes under mild conditions.
TL;DR: This paper suggests a method of multi-dimensional fuzzy reasoning concerned with both modus ponens and modus tollens, and discusses an example to show how the method works.
TL;DR: In this article, the authors analyzed the oscillating transverse and longitudinal modes in semiconductor injection lasers using the density matrix formalism and derived the optimal range to obtain stable fundamental transverse mode operation with respect to several guiding factors.
Abstract: Mechanisms which determine the oscillating transverse and longitudinal modes in semiconductor injection lasers are discussed in this paper. The analysis is based on the semiclassical method in which the optical field is represented by Maxwell equations and the lasing phenomenon is analyzed quantum mechanically using the density matrix formalism. Guided modes are classified by the relation between refractive index and gain-loss differences at the boundaries of the active region as normal guided mode (index guiding), active-guided mode (gain guiding), and leaky mode (anti-index guiding). The guiding loss and cutoff conditions are given for these modes. The optimum range to obtain stable fundamental transverse mode operation is discussed with respect to several guiding factors, such as width of active region, the refractive index difference, and gain-loss differences at the boundaries of the active region. Longitudinal mode behavior is discussed in terms of electron transition mechanism in semiconductor crystals. The relaxation effect of the electron wave is introduced in this model. Profiles of the saturated gain and the spatial diffusion of the electron are related to this relaxation effect. Mode competition phenomena are analyzed, and a strong gain suppression among the longitudinal modes is shown to be as an intrinsic property of semiconductor lasers. The possibility of obtaining single longitudinal mode operation is postulated. Physical influences for stable single longitudinal mode operation are discussed in terms of transverse mode control (or stripe structure), spontaneous emission, threshold current level, impurity concentration in the active region, and direct modulation. Some experimental results are also given to support these analyses.
TL;DR: On adding PHMB, the fluorescence polarization of diphenylhexatriene embedded in the negatively charged bilayers was reduced to a great extent, especially in the gel phase, interpreted in terms of PHMB-induced expansion and fluidization of the bilayer, which enables the probe molecule to undergo less-hindered torsional motion.
TL;DR: The main theorems state that any 6-connected toroidal graph is uniquelly embeddable in a torus and that any6-connectedtoroidal graph with precisely three exceptions is faithfully embeddables in atorus.
TL;DR: In this paper, an efficient via minimization algorithm for certain types of two-layer printed circuit boards is developed which can be executed in polynomial time and yields solutions for routings with junctions of degrees varying from 2 to 8 and guarantees the minimum number of vias for routing with three or fewer line segments connected to each junction.
Abstract: Based on graph theory, an efficient via minimization algorithm for certain types of two-layer printed circuit boards is developed which can be executed in polynomial time. The algorithm yields solutions for routings with junctions of degrees varying from 2 to 8 and guarantees the minimum number of vias for routings with three or fewer line segments connected to each junction. Examples are given to illustrate various aspects of the algorithm. In addition, preassignment of line segments on a particular layer of the board due to certain prescribed board (or component) constraints is discussed.
TL;DR: In this article, the structural changes taking place during the tempering proceed in four stages, starting at 370 K, where interstitial carbon atom clusters are formed below 270 K, rearrange to make a modulated structure between 270 and 360 K, and disappear at about 370 K.
Abstract: Structural changes taking place during the tempering proceed in four stages. At the preliminary stage taking place below 370 K, interstitial carbon atom clusters are formed below 270 K, rearrange to make a modulated structure between 270 and 360 K, and disappear at about 370 K. A long period ordered phase with respect to the interstitial carbon atoms or interstitial vacancies also appears between 330 and 350 K. With the disappearance of these structures, the first stage takes place between 370 and 470 K, where η-Fe2C is formed in the matrix of low carbon martensite. The second stage occurs around 550 K with the retained austenite decomposing to θ-Fe3C and α iron. At the succession of the first stage, the third stage appears in a temperature range from 470 to 900 K, where θ-Fe3C, χ-Fe5C2 and also higher carbides θn-Fe2n+1Cn intergrow microsyntactically in the particles precipitated below 720 K, but only θ-Fe3C is formed above this temperature.
TL;DR: In this paper, a condition for the single-mode operation of a rapidly modulated DBR laser, called a "dynamic-singlemode laser," and the dynamic spectral width were theoretically presented.
Abstract: The theoretical bases and the experimental results of the dynamic behavior of 1.5-1.6 \mu m GaInAsP/InP dynamic-single-mode (DSM) lasers with distributed Bragg reflector (DBR) are given. A condition for the single-mode operation of a rapidly modulated DBR laser, called a "dynamic-single-mode laser," and the dynamic spectral width were theoretically presented. Experimentally, buried-heterostructure distributed-Bragg-reflector integrated-twin-guide (BH-DBR-ITG) and buried-heterostructure butt-jointed-built-in distributed-Bragg-reflector (BH-BJB-DBR) lasers emitting at the wavelength of 1.5-1.6 \mu m were directly modulated up to 3 GHz, and the stable single-mode operations were obtained in both types of lasers. The dynamic spectral width at the worst modulation condition was measured to be 0.27 nm, which was about \frac{1}{35} times smaller than that of conventional lasers.
TL;DR: In this article, the blocking effect on grain boundary sliding of second phase particles is formulated by the inclusion method and an expression similar to those obtained previously is recovered for the effective boundary viscosity at high temperatures.
TL;DR: The plant growth-promoting activities of brassinolide and brassinosteroids with different side chains were investigated by means of the Raphanus an.
TL;DR: In this paper, the elastic strain associated with the field-induced transition from an antiferroelectric phase to a ferroelectric one has been measured at several temperatures in a PZT-family ceramic Pb0·99Nb 0·02 [(Zr0·6Sn0·4)0·94Ti0·06]0·98 O3.
Abstract: The elastic strain associated with the field-induced transition from an antiferroelectric phase to a ferroelectric one has been measured at several temperatures in a PZT-family ceramic Pb0·99Nb0·02 [(Zr0·6Sn0·4)0·94Ti0·06]0·98 O3. Reproducible large strain change of about Δl/l∼ due to the forced transition may be promising for digital microdisplacement transducers. So-called “inverse hysteresis'’in the strain curve is observed in a temperature range between -70°C and 10°C, which is also useful as a shape memory device for mechanical clamping and similar applications.
TL;DR: In this paper, the authors describe the principle and performance of the new method, which facilitates formattion of crystalline spinel films at low temperature (<80°C) for various compositions, and on substrates of not only metal but also oxide and organic compounds.
Abstract: We describe the principle and performance of the new method. It facilitates formattion of crystalline-spinel films at low temperature (<80°C) for various compositions, and on substrates of not only metal but also oxide and organic compounds. Hydrolyzed metal ions in an aqueous solution (pH=6~11, T=40~80°C) are incorporated into the spinel film on the substrate associated with air oxidation or anodic oxidation of ferrous ion. We have plated Fe3O4 and CoFe2O4 films on substrate of Cu, PET and stainless steel. They are polycrystalline with no preferred orientation, exhibiting no magnetic anisotropy. Polar Kerr rotation of these films has been measured.