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Showing papers by "Tokyo Institute of Technology published in 1990"


Journal ArticleDOI
TL;DR: In this paper, a stable discrete sliding mode control insensitive to the choice of sampling interval and not yielding chattering is presented, which is based on a discrete Lyapunov function and a sufficient condition of the control gain to make the system stable is given.

849 citations


Journal ArticleDOI
TL;DR: An imaging system that can display both the amplitude and phase maps of internal vibration in soft tissues for forced low-frequency vibration is described, and the velocities of vibration are measured for some samples as well as in vivo.
Abstract: An imaging system that can display both the amplitude and phase maps of internal vibration in soft tissues for forced low-frequency vibration is described. In this method, low-frequency sinusoidal vibration of frequency under several hundred hertz is applied from the surface of the sample and the resulting movement in it is measured from the Doppler frequency shift of the simultaneously transmitted probe ultrasonic waves. Basic experiments are carried out by using 3.0-MHz ultrasonic waves. The two-dimensional maps of the amplitude and phase of internal vibration are shown, and the velocities of vibration are measured for some samples as well as in vivo. >

494 citations


MonographDOI
01 Aug 1990
TL;DR: Fujita as discussed by the authors develops classification theories of such pairs using invariants that are polarised higher-dimensional versions of the genus of algebraic curves, which is a modern generalization of the notion of a variety in classical algebraic geometry.
Abstract: A polarised variety is a modern generalization of the notion of a variety in classical algebraic geometry. It consists of a pair: the algebraic variety itself, together with an ample line bundle on it. Using techniques from abstract algebraic geometry that have been developed over recent decades, Professor Fujita develops classification theories of such pairs using invariants that are polarised higher-dimensional versions of the genus of algebraic curves. The heart of the book is the theory of D-genus and sectional genus developed by the author, but numerous related topics are discussed or surveyed. Proofs are given in full in the central part of the development, but background and technical results are sometimes just sketched when the details are not essential for understanding the key ideas. Readers are assumed to have some background in algebraic geometry, including sheaf cohomology, and for them this work will provide an illustration of the power of modern abstract techniques applied to concrete geometric problems. Thus the book helps the reader not only to understand about classical objects but also modern methods, and so it will be useful not only for experts but also non-specialists and graduate students.

410 citations



Journal ArticleDOI
24 Aug 1990-Cell
TL;DR: The segment of residues 2410-2423 in the human IGF-II/man6PR activates Gi-2 in a manner similar to G-coupled receptors, indicating a critical role for this small region of the receptor.

286 citations


Journal ArticleDOI
TL;DR: In this paper, a data sample of 1040 days from the Kamiokande II detector, consisting of subsamples of 450 days at electron-energy threshold = 9.3 MeV and 590 days at = 7.5 MeV, yields a clear directional correlation of the solar-neutrino-induced electron events with respect to the Sun and a measurement of the differential electron energy distribution.
Abstract: A data sample of 1040 days from the Kamiokande II detector, consisting of subsamples of 450 days at electron-energy threshold ${\mathit{E}}_{\mathit{e}}$\ensuremath{\ge}9.3 MeV and 590 days at ${\mathit{E}}_{\mathit{e}}$\ensuremath{\ge}7.5 MeV, yields a clear directional correlation of the solar-neutrino-induced electron events with respect to the Sun and a measurement of the differential electron-energy distribution. These provide unequivocal evidence for the production of $^{8}\mathrm{B}$ by fusion in the Sun. The measured flux of $^{8}\mathrm{B}$ solar neutrinos from the two subsamples relative to a prediction of the standard solar model is 0.46\ifmmode\pm\else\textpm\fi{}0.05(stat)\ifmmode\pm\else\textpm\fi{}0.06(syst). The total data sample is tested for short-term time variation; within the statistical error, no significant variation is observed.

266 citations


Journal ArticleDOI
TL;DR: Design of a practical mobile robot is attempted, with an inspection task in a nuclear reactor as a concrete objective for development, and basic control problems such as signal process ing for tactile sensors and control of statically indeterminant forces are investigated.
Abstract: Mobile robots having good terrain adaptability, sufficient payload capability, and high mobility are now urgently in de mand In this paper, design of a practical mobile robot is attempted, with an

247 citations


Journal ArticleDOI
01 Sep 1990-EPL
TL;DR: In this article, the double-beta decay rates for all potential ββ emitters with A≥-70 were predicted and the nuclear transition matrix elements were calculated within the QRPA with a realistic effective nucleon-nucleon interaction.
Abstract: 2ν and 0ν double-beta decay rates for all potential ββ emitters with A ≥ 70 are predicted. The nuclear transition matrix elements are calculated within the QRPA with a realistic effective nucleon-nucleon interaction. The results for neutrinoless decays are rather insensitive to details of the nuclear structure, except for the cases of 70Zn, 100Mo and 148Nd.

238 citations


Journal ArticleDOI
19 Jul 1990-Nature
TL;DR: In this paper, the reduction of CO2 to carbon using cation-excess magnetite has been studied and shown to achieve an efficiency of nearly 100% at 290 °C using Fe3+δO4, δ = 0.127.
Abstract: THE reduction of gaseous oxides such as CO2 and H2O is an important concern in industrial processes and pollution control. Here we report the reduction of carbon dioxide to carbon with an efficiency of nearly 100% at 290 °C using cation-excess magnetite (Fe3+δO4, δ =0.127). In this reaction, the oxygen in the CO2 is transferred, in the form of O2−, to the cation-excess magnetite, and no gas is evolved. The carbon in the CO2 is reduced to carbon (zero valence) by the addition of an electron donated from the cation-excess magnetite to maintain electrical neutrality during the transfer of the O2− to the magnetite. When we used H2O in place of CO2, hydrogen gas was evolved, indicating that the same mechanism can also reduce H2O.

231 citations


Journal ArticleDOI
TL;DR: In this paper, the conoscopic figure in the antiferroelectric smectic CA* phase does not shift its center and is biaxial with its optic plane perpendicular to the field direction.
Abstract: Molecular orientational structures in MHPOBC were studied by means of conoscope observation. Contrary to a ferroelectric response of the conoscope to an electric field in the smectic C* phase, the conoscopic figure in the antiferroelectric smectic CA* phase does not shift its center and is biaxial with its optic plane perpendicular to the field direction. This conoscope change is only due to a dielectric contribution, indicating the existence of the inherent threshold in the electric field induced transition to the ferroelectric phase. In between the ferroelectric and antiferroelectric phases, a kind of ferrielectric phase was clearly distinguished in the field response of the conoscopic figure; the shift of the conoscope center perpendicular to the applied field and the biaxial optic plane parallel to the field suggest a novel molecular orientational structure.

216 citations


Journal ArticleDOI
TL;DR: The surface species formed from adsorption and decomposition of HCOOH, CH3OH, and HCHO over dehydroxylated cerium oxide have been identified using in situ Fourier transform infrared spectroscopy at temperatures from 300 to 673 K as mentioned in this paper.


Journal ArticleDOI
TL;DR: A proposed biosynthetic pathway of P(3HB-co-4HB) film was shown to be biodegradable in an activated sludge and to have random sequence distribution of 3HB and 4HB units by analysis of the 125 MHz 13C n.r.m. spectra.

Journal ArticleDOI
TL;DR: In this paper, it was shown that poly(N-isopropylacrylamide) behaves as a flexible coil from the molecular weight dependence of these parameters and the relation between the interpenetration function and expansion coefficients.
Abstract: Various molecular parameters characterizing the solution properties of poly(N-isopropylacrylamide) (in the range of molecular weight from 13.8 to 910×104) in water at 20°C and the temperature dependence of them in the range of 20°C to 30.6°C were determined with static and dynamic light scattering technique. (Modified) Flory’s fifth power law of excluded volume effect predicts well the temperature dependence of the chain dimension. It is shown that this polymer molecule behaves as a flexible coil from the molecular weight dependence of these parameters and the relation between the interpenetration function and expansion coefficients. The unique thermal behavior of this solution, temperature of phase change being independent of molecular weights and concentrations at least in the range of 1 wt%, should be mainly attributed to the hydrated structure.

Journal ArticleDOI
TL;DR: In this article, the degradation rates of odorous sulfur compounds, such as hydrogen sulfide (H2S), methanethiol (MT), and dimethyl sulfide, on peat biofilters were measured.

Journal ArticleDOI
TL;DR: Some ion exchangeable niobates with a layered perovskite structure were found to be a new class of heterogeneous photocatalysts due to the unique structure of those materials as discussed by the authors.
Abstract: Some ion-exchangeable niobates with a layered perovskite structure were found to be a new class of heterogeneous photocatalysts due to the unique structure of those materials, and were suggested to work as “two-dimensional” photocatalysts in which catalytic reactions mainly proceed at interlayer spaces.

Journal ArticleDOI
TL;DR: Etude de la transition de phase induite par la photoisomerisation dans les polyacrylates de ω-[methoxy-4' phenoxycarbonyl-4 phenoxy] alkyle dopes par un compose mesogene photoisommeable and dans the copolymeres du meme acrylate avec un acrylated de ε-(methox 4 phenylazo-4phenoxy) alkyle as discussed by the authors.
Abstract: Etude de la transition de phase induite par la photoisomerisation dans les polyacrylates de ω-[methoxy-4' phenoxycarbonyl-4 phenoxy] alkyle dopes par un compose mesogene photoisomerable et dans les copolymeres du meme acrylate avec un acrylate de ω-(methoxy-4 phenylazo-4 phenoxy] alkyle. Relation avec la vitesse de la transition et la longueur de l'espaceur alcoxy et l'ordre orientationnel initial du polymere. Evaluation du polymere comme materiau de stockage d'image

Journal ArticleDOI
TL;DR: The authors examine en particulier l'influence des amines sur l'oxydation du cholesterol dans les conditions du titre, and examine les amines' influence on l'oxygenation of LDL.
Abstract: On examine en particulier l'influence des amines sur l'oxydation du cholesterol dans les conditions du titre

Journal ArticleDOI
TL;DR: In this article, a determination par DSC des parametres thermodynamiques des transitions nematique-isotrope and des paramets d'ordre orientationnel de polyacrylates de ω-[methoxy-4' phenoxycarbonyl-4 phenoxy] alkyle and de copolymeres du meme acrylate avec un acrylated de δ-methyltropane alkyle en fonction de la longueur de la chaine alkyl was made.
Abstract: Determination par DSC des parametres thermodynamiques des transitions nematique-isotrope et des parametres d'ordre orientationnel de polyacrylates de ω-[methoxy-4' phenoxycarbonyl-4 phenoxy] alkyle et de copolymeres du meme acrylate avec un acrylate de ω-[methoxy-4 phenylazo-4 phenoxy] alkyle en fonction de la longueur de la chaine alkyl

Proceedings ArticleDOI
04 Dec 1990
TL;DR: In this article, a technique for measuring hardness in which the impulsive radiation force is focused ultrasound is used to generate localized deformation of the tissue and the applied force and/or the deformation are measured as a function of time by a conventional pulse-echo technique is proposed.
Abstract: A technique for measuring hardness in which the impulsive radiation force is focused ultrasound is used to generate localized deformation of the tissue and the applied force and/or the deformation are measured as a function of time by a conventional pulse-echo technique is proposed An attempt is made to derive some characteristic values from the curve as figures of tissue hardness The decay of applied force measured while keeping the deformation constant proved to give a good figure This preliminary experiment indicates that the proposed technique is feasible >

Journal ArticleDOI
01 Nov 1990-Icarus
TL;DR: In this paper, the random velocity change of planetesimals due to mutual gravitational scattering is investigated, taking into account the solar gravitational field, and the results are summarized as follows: (1) the role of distant encounters is not important.

Journal ArticleDOI
TL;DR: The best conditions for the accumulation of H2O2 were as follows: M = Au-mesh, pH = 1.1 using HCl aq, pressure of hydrogen = 5 kPa, and pressure of oxygen ⩾ 101 kPa as discussed by the authors.

Journal ArticleDOI
TL;DR: A program for the automatic estimation of the logarithm of the partition coefficient between 1-octanol and water phases (log P) has been developed as a component of a system entitled CHEMICALC (Combined Handling of Estimation Methods Intended for Completely Automated Log P Calculation).
Abstract: A program for the automatic estimation of the logarithm of the partition coefficient between 1-octanol and water phases (log P) has been developed as a component of a system entitled CHEMICALC (Combined Handling of Estimation Methods Intended for Completely Automated Log P Calculation). Log P values are calculated based on additive group contributions to log P. Three sets of groups are defined, and their contributions have been derived from the experimental log P values of 1465 molecules. The system divides a structural formula of a compound of interest into the groups whose increments are provided and then calculates its log P value. All processing after structure input is fully automated. This system has been tested for predicting the log P values of 1686 compounds. The accuracy is sufficient for many practical purposes.

Journal ArticleDOI
TL;DR: Bacteria isolated from suppressive composts which showed clear zones inhibitory to the growth of phytopathogenic fungi in vitro on agar plates were identified to be Bacillus subtilis and the suppressiveness of the culture broth of these bacteria became obvious in in vivo tests.

Book
01 Jan 1990
TL;DR: In this article, the authors provide the reader with a detailed treatment of Weibull distribution as applied to radar systems, including general derivation, measurements, and comparison with various distributions including Rayleigh, gamma, log-nornal and k- distributions.
Abstract: The material presented in this book is intended to provide the reader with a pratical treatment of Weibull distribution as applied to radar systems. This book is primarily written for radar engineeres. Topics include: general derivation of Weibull distribution, measurements of Weibull-distributed clutter, comparison of Weibulkl distribution with various distributions including Rayleigh, gamma, log-nornal and k- distributions to name just a few.

Journal ArticleDOI
TL;DR: In this paper, an undrained cyclic triaxial tests were conducted using various sands under different confining pressures, to establish a relation between liquefaction resistance and shear wave velocity or elastic shear modulus.

Journal ArticleDOI
TL;DR: Results indicate the cyclic nature of PHA metabolism in A. eutrophus under these conditions, and a copolyster of 3-hydroxybutyrate and 3-Hydroxyvalerate units, P(HB-co-HV), was accumulated in the presence of pentanoic acid.
Abstract: The cyclic process of biosynthesis and degradation of poly(3-hydroxyalkanoate) (PHA) was studied in Alcaligenes eutrophus under conditions of nitrogen-limitation of growth. A. eutrophus cells, which had accumulated poly(3-ydroxybutyrate) (PHB) of 55 wt% content within cells from butyric acid, were transferred into a nitrogen-free medium containing pentanoic acid as the sole carbon source and cultivated at 30°C and pH 7.5. The content of PHB in A. eutrophus cells decreased with time, whereas a copolyster of 3-hydroxybutyrate (HB) and 3-hydroxyvalerate (HV) units, P(HB-co-HV), was accumulated in the presence of pentanoic acid. Conversely, when A. eutrophus cells with 50 wt% content of P(HB-co-56% HV) were incubated in a nitrogen-free medium containing butyric acid, the content of P(HB-co-56% HV) decreased with time, whereas PHB was accumulated. These results indicate the cyclic nature of PHA metabolism in A. eutrophus under these conditions.

Journal ArticleDOI
TL;DR: In this paper, a variational wave function is introduced to describe the Hubbard model in strong correlation in the presence of Intersite correlation (or Jastrow) factors beyond the Gutzwiller wave function.
Abstract: New variational wave functions are introduced to describe the Hubbard model in strong correlation Intersite correlation (or Jastrow) factors are taken into account beyond the Gutzwiller wave function (GF) A study is made on the one-dimensional lattice and the two-dimensional square lattice at half-filling as well as less-than-half-filling Much improvement can be achieved thereby in the description of physical quantities such as the momentum distribution and spin and charge density correlation functions In addition, the ground state energy is lowered appreciably compared with the GF In this connection, the Mott-Hubbard-type metal-insulator transition is also re-examined