Showing papers by "University of Electro-Communications published in 1975"
TL;DR: In this method, an object's shape is determined by touching, groping and grasping it with an artificial hand with tactile sense with highly reliable results.
38 citations
TL;DR: In this article, the authors developed the quantum theory of a one-dimensional optical cavity with emphasis on the presence of output coupling and the effect of the small size of the cavity on the radiation field.
Abstract: The quantum theory of a one-dimensional optical cavity is developed with emphasis on the presence of output coupling. First the resonant mode is defined and calculated classically. Then the field is decomposed into a sequence of modes by introducing an imaginary boundary at a large distance. The mode functions are proved to be orthogonal with respect to an integration with the dielectric constant as a weighting factor. The Hamiltonian of the field is shown to be equivalent to that of a collection of independent harmonic oscillators, the mass of which is a function of the frequency of oscillation. This equivalent of mass appears on normalizing the mode functions and proves to carry information on the structure of the cavity. Quantization of the field is carried out, and the commutation relation for the electric fields inside and outside the cavity is derived. The commutator is composed of an infinite set of derivatives of $\ensuremath{\delta}$ functions, which discloses the effect of the presence of output coupling and that of the small size of the cavity on the radiation field. Also, the commutator is shown to have some properties common with the classical resonant mode, i.e., the property of exponential decay and its rate.
38 citations
31 citations
TL;DR: In this paper, the structural phase transition temperature T a, where elastic anomaly occurred, was found to decrease with Ba-concentration, while it increased with Ca-centration.
Abstract: Elastic measurement has been done for single crystals of Sr 1- x Ba x TiO 3 ( x =0, 0.006, 0.012, 0.014) and Sr 0.941 Ca 0.059 TiO 3 in the temperature range from 4 K to 240 K. The structural phase transition temperature T a , where elastic anomaly occurred, was found to decrease with Ba-concentration, while it increased with Ca-concentration. Dielectric constants for the Sr 1- x Ba x TiO 3 system have also been measured with stress-treated crystals.
20 citations
TL;DR: In this paper, a low frequency E ( x, y )-mode Raman spectrum of a KH 2 PO 4 crystal is discussed in terms of the pseudo-spin model extended by Havlin et al. to the problem of transverse susceptibility.
Abstract: Low frequency E ( x , y )-mode Raman spectrum of a KH 2 PO 4 crystal is discussed in terms of the pseudo-spin model extended by Havlin et al. to the problem of transverse susceptibility. Temperature dependence of the susceptibility obtained from the integrated intensity of a broad continuum of the Raman spectrum can be well interpreted by their theory. The theory indicates that this mode, just like the B 2 ( z )-soft phonon mode, originates from a zone-center phonon corresponding to a collective proton motion in the a - b plane. Dynamics of the E -mode is also discussed in the framework of the pseudo-spin formalism and it is shown that this model is applicable not only to B 2 ( z ) soft mode but also, at least qualitatively, to the E ( x , y ) mode in spite of the apparently different behaviour of the two modes with respest to the phase transition.
16 citations
TL;DR: In this paper, the LCAO-MO scheme is used with account of configuration interactions (CI) to obtain the electronic structure around a Fe ion in I-III-VI 2 compounds, and the ground state has 6 A 1 symmetry and two 6 T 2 states, to which allowed transitions are expected, are obtained in an energy region below the fundamental absorption edge.
Abstract: The electronic states of a tetrahedral cluster of a Fe ion and four S ions are calculated in order to obtain the electronic structure around a Fe ion in I-III-VI 2 compounds. The LCAO-MO scheme is used with account of configuration interactions (CI). The ground state is found to have 6 A 1 symmetry and two 6 T 2 states, to which allowed transitions are expected, are obtained in an energy region below the fundamental absorption edge, in agreement with experiments. It is remarked that the ground 6 A 1 state arises by no means from the pure atomic d 5 configuration: mixing of charge transferred configurations is quite large. The energies of quartet states ( 4 T 1 , 4 T 2 ) are lower than those of the corresponding sextet states ( 6 T 1 , 6 T 2 ) in harmony with the observed optical spectra. Account of CI is essential to the findings.
11 citations
TL;DR: In this article, the effect of dynamical screening on the transition energies and transition moments in π-electron systems was studied by using a partitioning technique on the equations of motion.
Abstract: Dynamical screening in π-electron systems is studied by the equations of motion method. By using a partitioning technique on the equations of motion we can obtain simple expressions for the effect of dynamical screening directly on the transition energies and transition moments in π-electron systems. These results are used to study the effect of such screening in the N → V transition in ethylene. This procedure can be used to extend the equations-of-motion method to larger π-electron systems.
10 citations
TL;DR: In this article, the linear response theory for vibronic systems is applied to the analyses for the sharp J-band and the bands of the DNA-dye complexes as examples, and an analytical relationship for the bandwidths of polymer vibronic bands which are to be determined entirely by intermolecular interaction is derived and discussed in connection with damping parameters.
9 citations
TL;DR: In this article, the optical absorption spectra of CuGaS 2 :Co are observed at a room temperature and at 2 K in near infrared and visible regions, the low energy side of the absorption edge (20,000 cm -1 ) of the host crystal.
Abstract: The optical absorption spectra of CuGaS 2 :Co are observed at a room temperature and at 2 K in near infrared and visible regions, the low energy side of the absorption edge (20,000 cm -1 ) of the host crystal. The spectra show a broad band in the vicinity of 7,000 cm -1 and a fine structured band around 13,000 cm -1 . The fine structure of the upper band is analyzed by calculating the energy level scheme taking account of a low symmetry ( D 2 d ) crystal field and the spin-orbit coupling in addition to the cubic ( T d ) field. A reasonable choice of the parameters reproduces the observed spectra fairly well and give the g -shifts and zero field splitting constant which agree quite well with the observed values by Kaufmann et al. (Solid State Commun. 15 (1974) 1881).
8 citations
TL;DR: In this paper, it was shown that the normal random-phase RPA (n-RPA) shows the triplet instability for most molecules in the Nishimoto-Mataga approximation of electron-repulsion integrals, but this instability can be circumvented by the use of the renormalized RPA in which the correlated ground states are calculated by the second-order perturbation theory.
Abstract: Random-phase approximations (RPA) have been applied to the calculation of the triplet π-π* transition spectra of 18 conjugated molecules in the framework of Pariser-Parr-Pople approximations. It is found that the normal RPA (n-RPA) shows the triplet instability for most molecules in the Nishimoto-Mataga approximation of electron-repulsion integrals. However, it is shown that this instability can be circumvented by the use of the renormalized RPA (r-RPA) in which the correlated ground states are calculated by the second-order perturbation theory. It is also shown that even in the n-RPA the suitable parametrization of electron-repulsion integrals removes this instability. It is ascertained that such an increasing order of energies as ω(n-RPA)<ω(Tamm-Dancoff approximation)<ω(r-RPA) holds for most of energy levels.
8 citations
TL;DR: An MC-LCAO-MO approach for open-shell systems of unsaturated hydrocarbons having degenerate MO's is applied to naphthalene, calculating its molecular geometry and electronic spectrum as mentioned in this paper.
Abstract: An MC-LCAO-MO approach which has been proposed for open-shell systems of unsaturated hydrocarbons having degenerate MO's is applied to naphthalene, calculating its molecular geometry and electronic spectrum. The results are compared with those obtained by the usual semi-empirical SCF-CI method and with experiment. As for benzene, anthracene, phenanthrene and triphenylene, the bond lengths and the π-electron energies in their ground states are calculated in the same manner. Most of the calculated bond lengths are in fairly good agreement with experiment. The total π-electron energies of the ground states obtained by the MC-LCAO-MO and SCF-CI methods agree within about 0.01 eV when CI is included and within about 0.1 eV when CI is not invoked. It is found that the electronic spectrum of naphthalene obtained by the present method is in good agreement with that derived from the SCF-CI method and also explains most part of experiments. A detailed discussion is given on the calculated triplet-triplet absorption spectrum and its intensity distribution of naphthalene.
TL;DR: In this paper, the authors proposed a method to evaluate the cumulative cycle ratio for each particular specimen, with emphasis on scatter of life, based on the statistical considerations of crack propagation curves obtained experimentally with a large number of mild steel notched specimens, it is confirmed that fatigue life of individual specimen will be estimated from the rate of crack growth at earlier stage of fatigue.
TL;DR: In this paper, the authors conclude that the formalism proposed by Hirschfelder and Silbey is the most appropriate formalism for perturbation theory and propose a new formalism based on symmetry-adapted perturbations.
TL;DR: In this paper, the Adams-Gilbert equation is used to describe the relationship between distorted localized orbitals v a r φ in the real manifold and orbitals φ 0 of a chosen model subsystem.
Abstract: Properties of distorted localized orbitals obtained from the Adams-Gilbert equation are studied. An account is given of a relationship between distorted localized orbitals v a r φ in the real manifold and orbitals φ 0 of a chosen “model subsystem”. Each ϕ can be written as a sum of a “localized orbital” φ and the remaining part δφ in the virtual manifold. The orbital φ is defined through an equation with optimized pseudopotential which makes deviation of φ from the corresponding model orbital φ 0 least. It is shown that φ is equal to φ 0 up to the first order in δφ. Appropriateness of the choice of model subsystems or model orbitals in a particular polyatomic system can be judged by the relative magnitude of δφ to φ 0 . That is, the smaller | δφ/φ 0 | is, the better the choice of model orbitals. An expression of δφ convenient for a calculation is given.
TL;DR: In this paper, a simple relation between variances of these two distributions is derived from the normality of the two distributions, which expresses the number fluctuation in terms of the correlation coefficients between lengths of neighboring intervals.
Abstract: Asymptotic behaviors of the distribution of number of events in a fixed interval of time and of the distribution of interval length between the first and the N +1 st events of a stationary point process, where N is some fixed number, are discussed and a simple relation between variances of these two distributions is derived from the normality of the two distributions. From this a relation is derived which expresses the number fluctuation in terms of the correlation coefficients between lengths of neighboring intervals. Those behaviors and relations are confirmed by experiments in which the number of events and the length of the time interval are measured by electronic counters directly connected to a computer. Measurements are made for the zero-crossing points of a continuous Gaussian noise.
TL;DR: This paper describes studies of the TETAC system, an intelligent system which recognizes Morse code sent by hand and converts it to letters by means of online and real-time processing and evaluates the qualities of trainees' keying operations.
Abstract: This paper describes studies of the TETAC system (Teaching Equipment for Telegraph Technology Aided by Computer). The system has been developed for training students at the University of Electro-Communications. TETAC is an intelligent system which recognizes Morse code sent by hand and converts it to letters by means of online and real-time processing. In addition, the system evaluates the qualities of trainees' keying operations; namely, it identifies the students' faults or tendencies. Although TETAC is now in the testing stage, we are confident of the effectiveness of the training and of TETAC's usefulness in modernizing a maritime communication system.
TL;DR: Two characterization theorems of /oM (/oL) are given, one is in terms of homomorphism and intersection, and the other is in Terms of AFA with control set.
TL;DR: In this paper, it was shown that the normal random-phase RPA (n-RPA) shows the triplet instability for most molecules in the Nishimoto-Mataga approximation of electron-repulsion integrals, but this instability can be circumvented by the use of the renormalized RPA in which the correlated ground states are calculated by the second-order perturbation theory.
Abstract: Random-phase approximations (RPA) have been applied to the calculation of the triplet π-π* transition spectra of 18 conjugated molecules in the framework of Pariser-Parr-Pople approximations. It is found that the normal RPA (n-RPA) shows the triplet instability for most molecules in the Nishimoto-Mataga approximation of electron-repulsion integrals. However, it is shown that this instability can be circumvented by the use of the renormalized RPA (r-RPA) in which the correlated ground states are calculated by the second-order perturbation theory. It is also shown that even in the n-RPA the suitable parametrization of electron-repulsion integrals removes this instability. It is ascertained that such an increasing order of energies as ω(n-RPA)<ω(Tamm-Dancoff approximation)<ω(r-RPA) holds for most of energy levels.
01 Oct 1975
TL;DR: In this article, a new system to prevent collision accidents between cars and trains on railroad crossings is described in which microwave radiation from Gunn-diode oscillators are used to recognize obstacles.
Abstract: A new system to prevent collision accidents between cars and trains on railroad crossings is described in which microwave radiation from Gunn-diode oscillators are used to recognize obstacles. Experimental results are reported.
TL;DR: An MC-LCAO-MO approach for open-shell systems of unsaturated hydrocarbons having degenerate MO's is applied to naphthalene, calculating its molecular geometry and electronic spectrum.
Abstract: An MC-LCAO-MO approach which has been proposed for open-shell systems of unsaturated hydrocarbons having degenerate MO's is applied to naphthalene, calculating its molecular geometry and electronic spectrum. The results are compared with those obtained by the usual semi-empirical SCF-CI method and with experiment. As for benzene, anthracene, phenanthrene and triphenylene, the bond lengths and the π-electron energies in their ground states are calculated in the same manner. Most of the calculated bond lengths are in fairly good agreement with experiment. The total π-electron energies of the ground states obtained by the MC-LCAO-MO and SCF-CI methods agree within about 0.01 eV when CI is included and within about 0.1 eV when CI is not invoked. It is found that the electronic spectrum of naphthalene obtained by the present method is in good agreement with that derived from the SCF-CI method and also explains most part of experiments. A detailed discussion is given on the calculated triplet-triplet absorption spectrum and its intensity distribution of naphthalene.