Showing papers by "Nagoya Institute of Technology published in 1986"
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30 Jun 1986174 citations
TL;DR: In this paper, the thermal expansion of the skeletal framework was essentially zero for NaZr2(PO4)3-type compounds; the interstitialion, e.g., Na+, was primarily responsible for the total thermal expansion.
Abstract: The thermal expansion of the skeletal framework was essentially zero for NaZr2(PO4)3-type compounds; the interstitialion, e.g., Na+, was primarily responsible for the total thermal expansion. The composition dependence of the thermal expansion is discussed in terms of the amounts, crystallographic sites, and ionic radii of the interstitial ions. The mechanism which results in low thermal expansion was clarified, particularly for KZr2(PO4)3, in which a larger ion is substituted for Na+, and NbZr(PO4)3, which does not contain Na+. Polycrystalline ceramics formed from these crystals might be useful as thermal-shock-resistant materials.
155 citations
TL;DR: In this article, a new mixing rule which satisfies the asymmetry of a c and has two adjustable parameters is proposed for systems containing strongly polar substances, which still keeps the functional form of the conventional mixing rule.
154 citations
TL;DR: In this paper, a simple and general elastoplastic constitutive model for clay is proposed that describes the stress-strain behavior of clay under various stress paths in three-dimensional stresses.
87 citations
TL;DR: In this article, the relative stability of monoclinic and tetragonal ZrO2 in these ultrafine particles was studied by X-ray diffractometry, and it was concluded that the monOClinic phase was stabilized by the presence of water vapor, which probably decreases the surface energy.
Abstract: Mixtures of ultrafine monoclinic zirconia and aluminum hydroxide were prepared by adding NH4OH to hydrolyzed zirconia sols containing varied amounts of aluminum sulfate. The mixtures were heat-treated at 500° to 1300°C. The relative stability of monoclinic and tetragonal ZrO2 in these ultrafine particles was studied by X-ray diffractometry. Growth of ZrO2 crystallites at elevated temperatures was strongly inhibited by Al2O3 derived from aluminum hydroxide. The monoclinic-to-tetragonal phase transformation temperature was lowered to ∼500°C in the mixture containing 10 vol% Al2O3, and the tetragonal phase was retained on cooling to room temperature. This behavior may be explained on the basis of Garvie's hypothesis that the surface free energy of tetragonal ZrO2 is lower than that of the monoclinic form. With increasing A12O3 content, however, the transformation temperature gradually increased, although the growth of ZrO2 particles was inhibited; this was found to be affected by water vapor formed from aluminum hydroxide on heating. The presence of atmospheric water vapor elevates the transformation temperature for ultrafine ZrO2. The reverse tetragonal-to-monoclinic transformation is promoted by water vapor at lower temperatures. Accordingly, it was concluded that the monoclinic phase in fine ZrO2 particles was stabilized by the presence of water vapor, which probably decreases the surface energy.
72 citations
TL;DR: In this paper, the deformation and strength characteristics of clay in three-dimensional stresses are experimentally discussed, and the test results are compared with the analytical results by the well-known Cam-clay model and those by the tij-clays model which has recently been developed with reference to the extended concept of the Spatially Mobilized Plane.
69 citations
01 Jan 1986-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this article, the authors comprehensively represented the coarsening behaviors of precipitates in elastically constrained alloy systems and showed that they can be explained by the interfacial energy between the particle and matrix.
Abstract: Characteristic coarsening behaviours of precipitates in elastically constrained alloy systems are comprehensively represented. The important results obtained are as follows: (a) splitting of a precipitate into small particles during coarsening, (b) extremely slow coarsening of precipitates in high solute content alloys, (c) deceleration of the coarsening rate for large precipitates and (d) changes in the distribution function of particle size with progress of aging. These phenomena cannot be explained by the conventional Lifshitz-Slyozov-Wagner or modified Lifshitz-Slyozov-Wagner theories of Ostwald ripening, where only the interfacial energy between the particle and matrix is taken into account. The bifurcation diagrams of the particle stability can explain such extraordinary phenomena observed in elastically constrained alloy systems.
64 citations
TL;DR: In this article, a GaAs grown on Si substrates oriented 2° off (100) with intermediate layers of GaP, GaP/GaAs05P05/GaA superlattice, and GaAs05p05/GAAs super-lattices is characterized for different thickness of GaAs and different directions of the off angle of the Si substrate.
62 citations
TL;DR: In this paper, a multirate digital control design of an optimal regulator via singular perturbation theory is investigated, and the problem of the asymptotic stability of a multiirate controlled system is investigated.
Abstract: In this paper a multirate digital control design of an optimal regulator is investigated via singular perturbation theory. It is shown that the singularity perturbed continuous-time regulator leads, under slow and fast sampling rates, to two different discrete-time versions. They are decomposed into slow and fast subsystems, and then these solutions are combined in a proper way. Within the framework of such a decomposition-coordination principle, a multirate control design is developed naturally. Furthermore, the problem of the asymptotic stability of a multirate controlled system is investigated and the relationship between the original continuous-time version and the multirate controlled version is discussed.
55 citations
01 Jan 1986
46 citations
TL;DR: In this article, the morphological change of γ′ precipitates in some nickel-base alloys was investigated by means of transmission electron microscopy, and it was shown that the elastic interaction energies played an essential role in the development of such types of precipitate morphology as the above.
TL;DR: In this article, computer simulations of signals based on a dispersion equation involving diffusion, convection and chemical reaction terms are reported for systems with and without chemica reaction, and Concetration profiles of the reaction product in a straight, narrow tube were also stimulated; they explain satisfactorily the signal profiles obtained experimentally.
TL;DR: In this paper, the electrochemical oxidation of cyanide ion with and without coexistent metallic ions was studied and the PbO2-electrodeposited Ti anode was suitable for the purpose.
TL;DR: In this paper, the phase separation of Fe-Si and Fe-Al ternary alloys was investigated by means of transmission electron microscopy and two types of phase separation, B2+DO3 andα + DO3, were observed in the alloys whose compositions lie in a narrow band connecting Fe-10 to 14 at% Si with Fe-20 to 25 at % Al and also in the neighbourhood of a Fe-30 at%Al-3 at%Si alloy.
Abstract: Stable structures of Fe-Si-Al ternary alloys and Fe-Si and Fe-Al binary alloys containing up to about 40 at% solute atoms were investigated by means of transmission electron microscopy. The following results were obtained. Two types of phase separation, B2+DO3 andα + DO3 were observed in the alloys whose compositions lie in a narrow band connecting Fe-10 to 14 at% Si with Fe-20 to 25 at % Al and also in the neighbourhood of a Fe-30 at%Al-3 at% Si alloy. Such compositions of the alloys are located in the phase boundary of B2 and DO3 single phases orα and DO3 single phases. The phase separation in the Fe-Si-Al and Fe-Si alloys produce the 〈100〉 modulated structure which differs from the morphology formed by the phase separation of the Fe-Al system.
TL;DR: The morphology of corundum crystals, synthesized from a mixture of ≠-Al2O3 prepared from well-crystallized hydrated aluminum sulfate and reagent grade AlF3, was studied in this article.
TL;DR: In this paper, the fine structure parameters D and E are interpreted by two uniaxial spin-Hamiltonian terms along the c-axis of the host crystal and along the direction of the Cr 3+ -V M or Cr 3 + -Li + pair.
Abstract: Results of EPR measurements on Cr 3+ centres in Rb 2 ZnF 4 , Rb 2 CdF 4 and Cs 2 CdF 4 are reported for crystals co-doped with Li + ions. Due to charge compensation some of Cr 3+ ions are associated with a cation vacancy (V M ) or a Li + ion at the nearest divalent-cation site in the c -plane. The fine structure parameters D and E are interpreted by two uniaxial spin-Hamiltonian terms along the c -axis of the host crystal and along the direction of the Cr 3+ –V M or Cr 3+ –Li + pair. The validity of this interpretation is discussed by the superposition model.
TL;DR: The activities of GS analogs are found to correlate to the formation of the GS‐type conformation upon binding with phospholipid membrane.
Abstract: The proton nmr and CD spectra of gramicidin S (GS) cyclic-(Val1,1′-Orn2,2′-Leu3,3′-D-Phe4,4′-Pro5,5′)2 and of GS analogs—namely, [D-Ala4,4′]-GS, [Gly4,4′]-GS, and [L-Ala4,4′]-GS—were analyzed. The molecular conformation of [D-Ala4,4′]-GS is similar to that of GS, with the trans form about the D-Ala-Pro peptide bond. The molecular conformation of [Gly4,4′]-GS depends on the solvent composition of dimethylsulfoxide-d6/trifluoroethanol (DMSO)-d6/TFE and DMSO-d6/H2O as well as the solute concentration. In DMSO-d6 solution, [Gly4,4′]-GS forms the GS-type conformation of the monomer at lower concentration. At higher concentration, the GS-type conformer is converted to the other one that forms molecular aggregates. The cis form about the X-Pro peptide bonds is found for [Gly4,4′]-GS and [L-Ala4,4′]-GS in DMSO-d6 and for [L-Ala4,4′]-GS in TFE solution. The large temperature dependences of α-proton chemical shifts of [L-Ala4,4′]-GS in DMSO-d6 solution indicate that the conformer equilibrium changes with temperature. The GS-type conformation is not formed in [L-Ala4,4′]-GS. The two active peptide analogs, [D-Ala4,4′]-GS and [Gly4,4′]-GS, interact with the phospholipid membrane, taking the GS-type conformation. By contrast, an inactive analog, [L-Ala4,4′]-GS, does not interact with phospholipid membrane. The activities of GS analogs are found to correlate to the formation of the GS-type conformation upon binding with phospholipid membrane.
TL;DR: In this article, a di-2-pyridyl ketone benzoylhydrazone (DPKBH) was used for the spectrophotometric determination of trace amount of iron(II) in connection with the extraction process.
TL;DR: In this article, the formation field and composition of CSH in the presence of NaCl and/or NaOH were investigated to clarify their effects on the durability of concrete.
Abstract: Deep levels in MOCVD-grown GaAs using superlattice intermediate layers on Si substrates were investigated by DLTS. Electron traps at 0.44 and 0.73 eV were observed in the undoped n-type GaAs grown on (100)2° off Si substrates while only a 0.73-eV trap was detected in GaAs on a GaAs substrate. The deep-level concentration in GaAs/Si and the capture cross section of a 0.44-eV trap decreased and the half width of the 0.44-eV trap increased with increasing GaAs thickness. The 0.73-eV trap concentration increased upon decreasing the curvature radius of the wafer by polishing the back side of the Si substrate; however, that of 0.44 eV was unchanged. These observations suggest that the 0.44-eV trap is due to Si-defect complexes changing their shapes with the GaAs thickness and that of 0.73 eV is caused by point defects.
TL;DR: In this paper, a five-parameter van der Waals type cubic equation of state has been developed specifically for representing pure-component volumetric properties, based on the analysis of the variation of the attraction term contribution with reduced density.
TL;DR: In this paper, a model of a debonding and a crack occurring from a circular rigid inclusion in an infinite plate is analyzed as a mixed boundary value problem under uniform tension, and a mapping function represented in the form of a sum of a fractional expressions and complex stress functions are used.
Abstract: A model of a debonding and a crack occurring from a circular rigid inclusion in an infinite plate is analyzed as a mixed boundary value problem under uniform tension. A mapping function represented in the form of a sum of fractional expressions and complex stress functions are used. The stress distribution, stress intensity factors at the tip of a crack, and stress singular values at a debonded tip are presented. By using these stress singular values, the intensity of the debonded tip is also considered.
TL;DR: An approximate Markovian model for SRUC/GBN is developed which has a multidimensional state vector and the throughput and average message delay performance is derived.
Abstract: SRUC is an adaptive multiple access protocol which combines the slotted ALOHA protocol and a reservation protocol; it switches from one to the other according to the state of the channel. This paper studies SRUC with a go-back- N ARQ scheme (SRUC/GBN) in a satellite communication environment to improve the performance over SRUC with a stop-and-wait ARQ scheme (SRUC/SAW) previously studied. The performance of SRUC/GBN is analyzed in this paper, it is assumed that each user handles one message at a time and that the number of packets in a message is geometrically distributed. An approximate Markovian model for SRUC/GBN is developed which has a multidimensional state vector. The model is analyzed by the technique of equilibrium point analysis. The throughput and average message delay performance is derived. Numerical results from both analysis and simulation are given. The performance of SRUC/GBN is also compared with that of SRUC/SAW and other multiple access protocols.
TL;DR: In this article, the possibility of group transfer polymerization of methyl methacrylate-terminated polystyrene macromer (MA-PSt) was explored by using 1-methoxy-1-(trimethylsiloxy)-2-methyl-1-propene and tris(dimethylamino)sulfonium difluorotrimethylsilicate as initiator and catalyst, respectively.
Abstract: The possibility of group transfer polymerization of methyl methacrylate-terminated polystyrene macromer (MA-PSt) was explored by using 1-methoxy-1-(trimethylsiloxy)-2-methyl-1-propene and tris(dimethylamino)sulfonium difluorotrimethylsilicate as initiator and catalyst, respectively. The results obtained at the polymerization temperature of 0°C were undesirable. However, the oligomerization at -78°C gave almost quantitatively oligo(MA-PSt) of which the degree of polymerization was in good agreement with the mole ratio of macromer to initiator. The GPC curve of oligo(MA-PSt) was sharp and symmetrical. In addition, it was shown by the copolymerization with methyl methacrylate that the polymerizability of the macromer was markedly enhanced in the presence of methyl methacrylate comonomer.
TL;DR: The bidentate ligands, 4-(3,5-DiBr-PAEA) and 4-( 3,5,DiBr)-PAESA, react with silver(I) ion to form the Agl2 chelate in the presence of anionic or nonionic surfactant as mentioned in this paper.
TL;DR: In this paper, an adaptive steering system for ships that was developed by Nippon Kokan K.K. in cooperation with Yokogawa Hokushin Electric Corporation is described.
Abstract: This paper describes an adaptive steering system for ships that was developed by Nippon Kokan K.K. in cooperation with Yokogawa Hokushin Electric Corporation. The purpose of the system is to improve a ship's automatic steering performance under a variety of operational and environmental conditions. The techniques of hill climbing and model reference adaptive control are used in the course-keeping and course-changing modes, respectively. The results of related full-scale experiments with ocean-bound bulk carriers are presented.
TL;DR: In this article, the rapidly quenched structures of liquid Al-Mn-Zr ternary alloys and binary alloys were investigated by hardness tests, X-ray diffraction analyses, and TEM observations.
Abstract: The rapidly-quenched structures of liquid Al-Mn-Zr ternary alloys and Al-Mn binary alloys and their decomposition behaviors were investigated by hardness tests, X-ray diffraction analyses, and TEM observations. The solid solubility of Mn can be extended to about 10 wt pct irrespective of whether the alloys contain 1 wt pct Zr or not. The solidification structures are composed of fine dendritic cells and with increasing Mn content, interdendritic precipitates gather volume and branch out into the cell grains. The decomposition of rapidly-quenched alloys takes place during aging for 1 hour at temperatures of 300 to 350 °C, and the dependence of the decomposition temperatures on the Mn content varies in this range. Precipitation hardening of the ternary alloys is intensified by the addition of Mn up to about 7 wt pct and proceeds in a two-step manner during aging in the temperature range examined (350 to 450 °C). It is suggested that the precipitates contributing to the maximum hardening are pseudomorphous to the Al6Mn equilibrium phase.
TL;DR: Cristallisation des chaines laterales hexadecyle des polyhexadecyl-2 trimethylene alcanedioates synthetises a partir de l'hexadecycl-2 propanediol-1,3 et divers chlorures de diacides aliphatiques.
Abstract: Cristallisation des chaines laterales hexadecyle des polyhexadecyl-2 trimethylene alcanedioates synthetises a partir de l'hexadecyl-2 propanediol-1,3 et divers chlorures de diacides aliphatiques
TL;DR: Le compose du titre cristallise dans le systeme rhomboedrique, groupe P3 1 21 et sa structure est affinee jusqu'a R=0,031 as discussed by the authors.
Abstract: Le compose du titre cristallise dans le systeme rhomboedrique, groupe P3 1 21 et sa structure est affinee jusqu'a R=0,031
TL;DR: The complexation equilibria between aluminum, a masking agent (DCyTA, EDTA and citrate) and fluoride were studied in this paper, and the results showed that Citrate is more effective for masking aluminum than DCyTA or EDTA because of lower conditional formation constants of the mixed ligand complexes.