Showing papers by "Waseda University published in 1995"
TL;DR: Using angle-resolved electron spectroscopic methods, a monolayer film of hexagonal boron nitride epitaxially formed on Ni(111), Pd(111, and Pt(111) is investigated and indicates physisorption of the BN film.
Abstract: By using angle-resolved electron spectroscopic methods, we have investigated a monolayer film of hexagonal boron nitride ($h$-BN) epitaxially formed on Ni(111), Pd(111), and Pt(111). The electronic structure of the monolayer $h$-BN is almost independent of the substrate, which is in striking contrast with the case of monolayer graphite [A. Nagashima et al., Phys. Rev. B 50, 4756 (1994)]. The comparison of the present data with those for typical physisorbed systems indicates physisorption of the BN film.
294 citations
TL;DR: This article investigated the antecedents of commitment in IJVs from the major partners' perspective and found that commitment is largely a function of the perceived benefits of the relationship, i.e., satisfaction and economic performance.
Abstract: This study investigated the antecedents of commitment in IJVs from the major partners' perspective. Data were gathered from Japanese and local partners in IJVs located in eleven countries and analyzed in structural equations models. Results indicated that commitment is largely a function of the perceived benefits of the relationship, i.e., satisfaction and economic performance. However, exploration analyses of differences between local partners and the Japanese suggest that the effects of psychological antecedents might be contingent on the strategic intent of the relationship.
278 citations
TL;DR: Amino semitelechelic poly(N-isopropylacrylamide)s (PIPAAm) with three different molecular weights were synthesized by telomerization of IPAAm monomer with 2-aminoethanethiol as a chain transfer agent as mentioned in this paper.
Abstract: Amino semitelechelic poly(N-isopropylacrylamide)s (PIPAAm) with three different molecular weights were synthesized by telomerization of IPAAm monomer with 2-aminoethanethiol as a chain transfer agent, changing the molar ratio of monomer to chain transfer agent. Macromonomers of thermosensitive PIPAAm were synthesized by condensation reaction of amino semitelechelic PIPAAm with N-acryloxysuccinimide. The molecular weights of macromonomers determined by titration of the terminal amino groups were 2900, 4000, and 9000, respectively. The comb-type grafted PIPAAm hydrogels having different lengths of graft chains were synthesized by radical copolymerization of IPAAm monomer with PIPAAm macromonomer in the presence of N,N'-methylenebisacrylamide as a cross-linker. An important aspect of the graft-type gels is the construction of a molecular architecture different from PIPAAm normal type ofgel even though the composition is same. Higher equilibrium swellings at lower temperatures were observed in graft-type gels in contrast to the normal-type gel, and longer graft chains resulted in higher equilibrium swelling due to the freely mobile grafted chains. Both the normal-type and the graft-type gels exhibited reversible swelling-deswelling changes in aqueous milieu in response to an alteration of temperature. The deswelling kinetics at 40 °C changed from equilibrium swelling states at 10 °C, however, exhibited remarkable differences, and rapid responses were observed for graft-type gels. The rapid dehydration of graft chains during gel shrinking was confirmed by analysis of DSC measurements. These dehydrated graft chains strongly aggregated with hydrophobic intermolecular forces, inducing the rapid deswelling of the gels. The attractive forces operating between dehydrated chains were larger in the gel having longer grafted chains, resulting in faster deswelling. A deswelling mechanism distinct from polymer network collective diffusion was demonstrated with these comb-type grafted hydrogels having freely mobile grafted chains in the network.
262 citations
TL;DR: The strength of the interfacial bond and the influence of this bond upon the electronic states of the monolayer h-BN film is discussed on the basis of the observed band structures for the BN film and a film of monolayers graphite formed on Ni(111).
Abstract: Angle-resolved ultraviolet-photoelectron spectroscopy and angle-resolved secondary-electron emission spectroscopy have been carried out for a film of single-crystalline hexagonal boron nitride (h-BN) formed on the Ni(111) surface to investigate both the valence- and conduction-band structures. The thickness of the film studied in this experiment was 1 ML. The observed electronic dispersion relations were compared with some theoretical ones reported for bulk h-BN. Among these theoretical calculations, the one by Catellani et al. [Phys. Rev. B 36, 6105 (1987)] is in the best agreement with the present results. We have discussed the strength of the interfacial bond and the influence of this bond upon the electronic states of the monolayer h-BN film on the basis of the observed band structures for the BN film and a film of monolayer graphite formed on Ni(111).
253 citations
TL;DR: The unbinding force between an actin filament and a single motor molecule of muscle, myosin, in the absence of ATP is measured by pulling the filament with optical tweezers, suggesting that unbinding occurs sequentially at the molecular interface, which is an inherent property of motor molecules.
Abstract: The unbinding and rebinding of motor proteins and their substrate filaments are the main components of sliding movement We have measured the unbinding force between an actin filament and a single motor molecule of muscle, myosin, in the absence of ATP, by pulling the filament with optical tweezers The unbinding force could be measured repeatedly on the same molecule, and was independent of the number of measurements and the direction of the imposed loads within a range of +/- 90 degrees The average unbinding force was 92 +/- 44 pN, only a few times larger than the sliding force but an order of magnitude smaller than other intermolecular forces From its kinetics we suggest that unbinding occurs sequentially at the molecular interface, which is an inherent property of motor molecules
235 citations
TL;DR: A decapeptide called sodefrin was isolated from the abdominal gland of the cloaca of the male red-bellied newt, Cynops pyrrhogaster, and is the first amphibian pheromone to be identified and the first peptide phersomone identified in a vertebrate.
Abstract: A decapeptide called sodefrin was isolated from the abdominal gland of the cloaca of the male red-bellied newt, Cynops pyrrhogaster. The native peptide, as well as the synthetic one, had a female-attracting activity. Sodefrin was found in the apical portion of the epithelial cells of the abdominal gland. Sodefrin is apparently species specific because it did not attract females of Cynops ensicauda. This is the first amphibian pheromone to be identified and the first peptide pheromone identified in a vertebrate.
228 citations
TL;DR: Poly(IPAAm-co-DMAAm) enabled 'on-off' drug release in response to smaller temperature changes around the body temperature and the molecular design to control transition temperature and thermosensitivity of gel was established.
Abstract: —Temperature-responsive copolymer (or ternary copolymer) gels of N-isopropylacrylamide (IPAAm) were synthesized with hydrophobic alkyl methacrylate (RMA), hydrophilic acrylamide (AAm), N,N'-dimethylacrylamide (DMAAm), and N-acryloylpyrrolidine (APy) as comonomers. The effects of these comonomers on the phase transition temperature (LCST) and the thermosensitivity have been discussed. The LCST of poly(IPAAm) gel in phosphate buffered saline (PBS) was lowered by the introduction of hydrophobic RMA, and the change in equilibrium swelling ratio with temperature change became smaller with an increase in RMA content. However, a stable skin layer to achieve complete 'on-off' regulation of drug release was formed at a higher temperature by RMA due to hydrophobic interaction of alkyl chains. The LCST of poly(IPAAm-co-AAm) gel increased with an increase in AAm content. However, the thermosensitivity of the gel became smaller. It was suggested that hydrophilic AAm prevented the formation of a dense skin layer at a h...
190 citations
21 May 1995
TL;DR: A new joint mechanism, named "mechanical impedance adjuster", is presented, and an impedance control method of the robot finger joint by this mechanism is shown to be effective.
Abstract: The object of our work is to realize passive impedance on the joints of robot fingers by mechanical elements, as leaf springs and brakes, and to develop robot fingers using the new mechanism to grasp objects softly. This paper presents a new joint mechanism, named "mechanical impedance adjuster", and an impedance control method of the robot finger joint by this mechanism. The effectiveness of this method is shown by the experiment on a 1-DOF finger model.
175 citations
TL;DR: In this paper, the authors investigated the shrinking kinetics of copolymer gels with the hydrophilic comonomer, acrylamide, and hydrophobic comonomers, butyl methacrylate, and found that the shrinking process is dominated by polymer network diffusion.
146 citations
TL;DR: In this article, the metal/ceramic composite membrane is incorporated in the catalytic reactor, as demonstrated in concrete examples of steam and CO2 reforming of methane and dehydrogenation of isobutane.
134 citations
TL;DR: In this paper, higher-order conserved quantities of a class of nonlinear difference-difference equations which are related to the discrete-time Toda equation are obtained using the Miura transformations.
Abstract: Higher-order conserved quantities of a class of nonlinear difference-difference equations which are related to the discrete-time Toda equation are obtained using the Miura transformations.
TL;DR: In this paper, a homoepitaxial diamond (001) surface has been examined using a scanning tunneling microscope at an atomic scale and reflection electron microscopy at a macroscopic scale.
Abstract: The 2\ifmmode\times\else\texttimes\fi{}1/1\ifmmode\times\else\texttimes\fi{}2 surface reconstruction of a homoepitaxial diamond (001) surface has been examined using a scanning tunneling microscope at an atomic scale and reflection electron microscopy at a macroscopic scale. The monohydride dimer, which is a unit of the surface reconstruction, has a symmetric structure. These monohydride structures contribute to the surface p-type conduction in undoped films. The surface is composed of elongated dimer rows. Antiphase boundaries have been observed, which is indicative of low-temperature epitaxy where surface migration is limited. Macroscopic surface flatness has been improved during the growth stage in the presence of oxygen and boron which enhance migration.
01 Feb 1995
TL;DR: A nominal model as well as a set of models in which the real system is assumed to reside are derived, which directly yield uncertainty frequency weighting function of the designed control system.
Abstract: This paper deals with /spl mu/-synthesis of an electromagnetic suspension system. First, an issue of modeling a real physical electromagnetic suspension system is discussed. We derive a nominal model as well as a set of models in which the real system is assumed to reside. Different model structures and possible model parameter values are fully employed to determine unstructured additive plant perturbations, which directly yield uncertainty frequency weighting function. Second, based on the set of plant models, we setup robust performance control objectives. Third, we make use of the D-K iteration approach for the controller design. Finally, implementing the controller with a digital signal processor, experiments are carried out. With these experimental results, we show robust performance of the designed control system. >
TL;DR: In this article, the authors investigated the charge discharging behavior of a lithium metal anode in propylene carbonate (PC) electrolyte containing added lithium using in situ ac impedance measurements during galvanostatic cycling.
Abstract: The charge‐discharge behavior of a lithium metal anode in propylene carbonate (PC) electrolyte containing added was investigated using in situ ac impedance measurements during galvanostatic cycling. In PC electrolyte with , the anode's cycle life was twice as long and its charge transfer resistance was smaller than in the same electrolyte without . These enhancements are observed only when lithium is electrodeposited in the presence of on nickel substrate; the enhancement does not occur when lithium is deposited without and is cycled with . Even large amounts of in the electrolyte during cycling do not adversely affect the cycle life enhancement by . The enhancement seems to be due to products formed by reaction of lithium with on the electrodeposited lithium surface.
TL;DR: In this article, a PbTiO3 ferroelectric film 813 A was grown on a CeO2/Si(100) substrate by the digital chemical vapor deposition method.
Abstract: A PbTiO3 ferroelectric film 813 A thick was grown on a CeO2/Si(100) substrate by the digital chemical vapor deposition method. As the buffer layer between the perovskite PbTiO3 film and Si substrate, a CeO2 intermediate layer was grown on the Si(100) substrate using an ultrahigh vacuum (UHV) system. The density of surface states at the CeO2/Si(100) interface was estimated from the capacitance-vs-voltage (C-V) characteristics of Al/CeO2/Si(100) samples to be 8×1011/cm2 eV, and CeO2 films on Si(100) are therefore expected to be suitable as gate oxides for metal/ferroelectric/semiconductor-field-effect transistors (FETs). Experimental results derived from the C-V characteristics of metal/ferroelectric/insulator/semiconductor (MFIS)-structured samples show that the MFIS structure has ferroelectric switching properties, as demonstrated by the roughly 2.4 V threshold hysteresis in its C-V characteristics ("memory window"). Furthermore, the retention time of the MFIS sample was estimated to be 100,000 s by measuring the time dependence of capacitance at the voltage at the centuer of the memory window. Interfacial lines of the MFIS structure were clear in a transmission electron microscope image, and an amorphous CeOx layer and an amorphous SiO2 layer were seen between the Si substrate and PbTiO3 film. Secondary ion mass spectroscopy revealed that there was little diffusion of Si atoms into the PbTiO3 layer on the CeO2/Si substrate.
21 May 1995
TL;DR: A special foot mechanism with shock-absorbing material is introduced that stabilizes dynamic biped walking and acquires position information on the landing surface and decreases vibration around the pitch axis, decreased torque demands on ankle actuators on the pitchaxis, and acquired landing surface information were achieved.
Abstract: As the first stage of dynamic biped walking adapting to an unknown uneven surface using an anthropomorphic biped walking robot, this paper introduces a special foot mechanism with shock-absorbing material that stabilizes dynamic biped walking and acquires position information on the landing surface. The new foot has three functions: (1) a function to obtain information on the position relative to a landing surface; (2) a function to absorb the shock of the foot landing; and (3) a function to stabilize changes in the support leg. Two units of the foot mechanism were produced, a biped walking robot WL-12RVI that had the foot mechanism installed inside it was developed and a walking experiment with WL-12RVI was performed. As a result, decreased vibration around the pitch axis, decreased torque demands on ankle actuators on the pitch axis, increased dynamic biped walking success probability, and acquired landing surface information were achieved.
Proceedings Article•
01 Jan 1995TL;DR: A beat tracking system that processes musical acoustic signals and recognizes temporal positions of beats in real time and manages multiple agents that predict beats by using autocorrelation and cross-correlation according to different strategies is presented.
Abstract: This paper presents a beat tracking system that processes musical acoustic signals and recognizes temporal positions of beats in real time. Most previous systems were not able to deal with audio signals that contained sounds of various instruments, especially drums. Our system deals with popular music in which drums maintain the beat. To examine multiple hypotheses of beats in parallel, our system manages multiple agents that predict beats by using autocorrelation and cross-correlation according to different strategies. In our experiment with eight pre-registered drum patterns, the system implemented on a parallel computer correctly tracked beats in 42 out of 44 commercially distributed popular songs.
TL;DR: Using the LET distribution obtained by CR-39 plastic track detectors and the total absorbed dose obtained by TLDs, whose response for relativistic heavy ions is proportional to the absorbed dose, the dose equivalents at various locations inside the Space Shuttle (STS-47) have been estimated as mentioned in this paper.
Book•
24 Nov 1995TL;DR: In this paper, a functional analytic approach to initial boundary value problems for semilinear parabolic differential equations is presented, with a focus on the relationship between analytic semigroups and initial boundary values.
Abstract: A careful and accessible exposition of a functional analytic approach to initial boundary value problems for semilinear parabolic differential equations, with a focus on the relationship between analytic semigroups and initial boundary value problems. This semigroup approach is distinguished by the extensive use of the ideas and techniques characteristic of the recent developments in the theory of pseudo-differential operators, one of the most influential works in the modern history of analysis. Complete with ample illustrations and additional references, this new edition offers both streamlined analysis and better coverage of important examples and applications. A powerful method for the study of elliptic boundary value problems, capable of further extensive development, is provided for advanced undergraduates or beginning graduate students, as well as mathematicians with an interest in functional analysis and partial differential equations.
TL;DR: It is suggested that the medial preoptic area is closely related to the medial amygdala in regulation of male rat copulatory behavior, and these areas may play a critical role in the behavior as an unitary system.
TL;DR: In this article, a photoluminescence (PL) study was performed on B or P ion-implanted thermal SiO2 films and two PL bands at 4.3 and 2.6 eV were observed.
Abstract: Photoluminescence (PL) study was performed on B or P ion‐implanted thermal SiO2 films. Two PL bands at 4.3 and 2.6 eV were observed. For the 4.3 eV bands, two PL excitation (PLE) bands were observed at 5.0 and 7.4 eV. Based on the close similarities of the PL and PLE bands to those observed in oxygen‐deficient‐type bulk silica, the 4.3 and 2.6 eV PL bands are ascribed to the oxygen‐deficient‐type defects induced by ion implantation. While the 4.3 eV PL band in the bulk SiO2 decays exponentially, the decay of the corresponding PL band in the implanted thermal SiO2 films follows a power low or stretched exponential, suggesting the distribution of PL lifetimes. This suggests that the oxygen‐deficient‐type defects induced by the ion implantation in thermal SiO2 films are perturbed by the structural distribution of the surrounding Si‐O‐Si network, including the concentration of PL quenching centers.
TL;DR: In this article, the reactivities of neutral and cationic alkyl and aryl-palladium and platinum complexes were compared, and it was shown that the creation of a vacant site adjacent to a ligand bound to the palladium center causes a marked enhancement in the reactivity of these Group 10 metal alkyls and aries toward β-hydrogen elimination, and olefin or CO insertion.
01 Oct 1995
TL;DR: In this paper, the authors made dielectric, magnetic and magnetoelectric measurements on single-crystal samples of TbMn2O5, which was an antiferromagnet with the Neel temperature of approximately 40 K.
Abstract: We made dielectric, magnetic and magnetoelectric measurements on single-crystal samples of TbMn2O5, which was an antiferromagnet with the Neel temperature of approximately 40 K. From the results, we concluded that there were two groups of phase transitions at lower temperatures. The first group are three successive transitions at 29.3, 27.2 and 25.6 K, whose natures are probably electric. The crystal is polar below this temperature range, because the polarity of the magnetoelectric effect can be controlled by electric field cooling. Another transition exists at 8 K, where time inversion symmetry breaks. It is related to the ordering of Tb3+ magnetic moments.
TL;DR: In this paper, the lead-free piezoelectric properties of (Bi1/2Na 1/2)1-x (Sr1/ 2Ca 1/ 2) x TiO3 system were studied from the viewpoint of lead-fraction free materials, and MnO was added to improve electromechanical properties.
Abstract: In this paper, piezoelectric properties of (Bi1/2Na1/2)1–x (Sr1/2Ca1/2) x TiO3 system were studied from the viewpoint of lead-free piezoelectric materials To improve electromechanical properties in this system, MnO was added to this system In the composition of x = 013 which was close to morphotropic phase boundary (MPB), electromechanical properties such as kt and Qm were increasing with increase of the amount of MnO and took maximum value (kt ≊ 47%, Qm ≊ 367) at about 04 wt% On the other hand, dielectric constant ϵ r was decreasing with it and took comparatively lower value (ϵ33/ϵ0 = 518)