Showing papers by "Nagoya Institute of Technology published in 1970"

Theory of nonlinear damping due to dislocation hysteresis

Abstract: The nonlinear phenomena of damping are analysed in detail and formulated in two integral transformations; the volume and time integrals. This formulation enables one to examine the relationship between damping and tensile experiments in the microstrain range, and to describe the phenomena consistently in terms of dislocation behavior. An analysis of the amplitude-dependent internal friction is made by the use of the breakaway and friction models under the quasi-static condition. The generalized friction model is presented, which is the most appropriate for the analysis of internal friction under the steady-state vibrations in usual experiments. Several convenient formulae are given for the interpretation on dislocation mechanisms. This approach includes some earlier work such as the Granato-Lucke theory and the Davidenkov-Pisarenko formulation as a special case. In addition, the applicability of the Granato-Lucke theory is critically examined with reference to recent observations of stress-strain hysteresis.

Synthesis of tobermorite from zeolite

Abstract: Tobermorite rich in Al and with the basal spacing of 11A was synthe sized by treating zeolite (clinoptilolite)-lime mixtures under saturated steam pressure and at temperatures of 90-180•Ž. The synthetic tobermorite was found anomalous in the thermal behavior; the basal spacing of 11.4-11.7A is not changed significantly by heating for 24 hours at 300•Ž or for 14 days at 700•Ž, until conversion to wollastonite occurs at 800•Ž. About 16% of Si in the synthesized tobermorite is substituted by Al from clinoptilolite. This substitution causes the increase of the basal spacing. The main Si-O lattice vibration indicated by the infrared spectra does not shift as the result of such substitution, but the bands at 1220 and 1065 cm-1 of Al-free tobermorite are found to shift to lower frequency region. The synthetic tobermorite is platy with a cleavage after (001) and is elongated parallel to b.

General description of mechanical anisotropy of semicrystalline polymers in relation to orientation of structural units composed of crystalline and noncrystalline materials

Abstract: A mathematical representation of the transformation of an orientation function between two sets of Cartesian coordinates is discussed in terms of a series expansion of the distribution function in generalized spherical harmonics. A general procedure for calculating the mechanical anisotropy of a single-phase system (a polycrystalline material) from the orientation of its structural units and the intrinsic mechanical anisotropy of the structural unit is discussed in relation to the transformation of the orientation distribution function, i.e., mutual conversion of the coefficients in the expansion of the distribution function between the two sets of Cartesian coordinates. The procedure is extended to a two-phase systems (semicrystalline polymers) containing structural units composed of crystalline and noncrystalline materials in three different geometrical arrangements.

Atomic Absorption Spectrometry Analysis of Silicates by the Absorption Tube Technique

Abstract: By the combined use of the absorption tube technique and solvent extraction, determination of cadmium, cobalt, copper, iron, lead and nickel in silicate rocks was investigated. Applicable concentration range was from 0.1 to 1.Oppm for all the elements except cadmium, for which the range was from 0.005 to 0.025ppm. The accuracy and recovery determined by the use of standard samples from the United States National Bureau of Standards and Geological Survey were satisfactory for practical purposes.

Time Dependent Internal Friction in Tin Crystals

Abstract: The time changes in the amplitude dependent internal friction are studied in β-tin crystals, 99.99% pure, and oriented for the [001] slip. The measurements are made during the free decay of transverse vibration. Comparison of the results with the theory of Granato and Lucke leads to the following conclusions: (a) The length of movable dislocation increases as the amplitude of excitation is increased. (b) The length also increases with the duration of excitation at constant driving force, as log (γ t +1). This is considered to be due to breakaway from the atmosphere of solute atoms. After the breakaway, the diffusion of solute atoms from the atmosphere of the movable dislocation takes place, around room temperature. At low temperatures, the diffusion does not take place, but the brokenaway dislocation moves large distances in the lattice. The amplitude dependent internal friction is in this case caused by the interaction of the movable dislocation with the solute atoms distributed in the lattice.

STUDIES OF RECOMBINATION CENTERS IN GAMMA-IRRADIATED p-TYPE SILICON.

Abstract: Recombination centers produced by Co 60 γ-ray irradiation at room temperature were investigated by measuring the temperature dependence and the annealing behaviors of the minority carrier lifetime Both isochronal and isothermal annealing of the lifetime at a fixed measurement-temperature were observed The measurement at 150°K show that A-center at E C –017 eV is the most effective recombination center about the region of this temperature in all p -type specimens The first order annealing process with an activation energy of 127 eV was found in agreement with the values reported earlier The capture cross section for electrons and holes were estimated to be 12×10 -15 cm 2 and 18×10 -14 cm 2 , respectively The introduction rate of inverse lifetime measured at 150°K seems to show that A center is introduced at nearly the same rate in both floating zone and pulled crystals At and above room temperature the recombination center at ∼ E V +03 eV was found to control the lifetime The annealing activati

Atomic Absorption Spectrophotometry with the Absorption Tube Technique

Abstract: A device to increase the sensitivity of the atomic absorption spectrophotometric measurement by elongating the absorption path length has originally been developed by Fuwa and Vallee and the present authors called it “absorption tube technique” Although the technique has been fully described in comparison with the flame photometry, and the behavior of the elements and the reactions in the tube were investigated for several elements, application of a newly designed ring burner to this technique and the detailed examination of the operating conditions have never beer, published

Time and Orientation Dependent Internal Friction in Tin Crystals

Abstract: The time changes in the amplitude dependent internal friction are studied in β-tin crystals, 99.99% pure, and oriented as the [001] axis is nearly perpendicular to the specimen axis. The measurements are made during the free decay of transverse vibration, at temperatures from 90°C to -196°C. Contrary to the results obtained in the crystals oriented for the [001] single slip, it is found that the internal friction decreases with the time of excitation, and increases with the time of rest after the excitation. At low temperatures, discontinuous change in the strain amplitude occurs when the measurements are made under constant driving force.

Client Driven System of Depth Image Based Rendering

Abstract: In this paper, we propose systems which can render free viewpoint images by using depth image based rendering for live video communications. Experimental results show that an image and depth transmission system is more suitable than an all multi view transmission and an only free viewpoint image transmission system. Especially in the image and depth transmission system, transmitting two images and one depth map, and then predicting the opposite depth map is the best for live communication.

The NMR Spectra of Styrene-Itaconate Ester Copolymers Obtained by Free Radical Mechanism

Abstract: Styrene copolymerized with dimethyl itaconate and with methyl benzyl itaconate by use of a free radical initiator. Monomer reactivity ratios for styrene (M1)-dimethyl itaconate (M2) co-polymerization were r1 = 0.50 and r2 = 0.06 and for styrene (M1-methyl benzyl itaconate (M2), r1 = 0.42 and r2 = 0.19. The nonconjugative methoxycarbonyl affected the monomer reactivity of itaconate toward polystyrene radical. The NMR spectra of styrene-dimethyl itaconate copolymers were very complex and could not be interpreted because the two methoxy groups have similar chemical shifts. The NMR spectra of styrene-itaconate copolymers were not so complex if methyl benzyl itaconate was used as comonomer instead of dimethyl itaconate. Methoxy and benzyloxy absorptions were sufficiently separated and “co-isotacticity” could be determined. It is shown that the nonconjugative methoxycarbonyl group had little influence on the steric course of the cross-propagation reaction between styrene and itaconate.

Depth Map Renement Using Reliability Based Joint Trilateral Filter

Abstract: In this paper, we propose a renement lter for depth maps. The lter convolutes an image and a depth map with a cross computed kernel. We call the lter joint trilateral lter. Main advantages of the proposed method are that the lter ts outlines of objects in the depth map to silhouettes in the im- age, and the lter reduces Gaussian noise in other areas. The eects reduce rendering artifacts when a free viewpoint image is generated by point cloud ren- dering and depth image based rendering techniques. Additionally, their computational cost is independent of depth ranges. Thus we can obtain accurate depth maps with the lower cost than the conventional ap- proaches, which require Markov random eld based optimization methods. Experimental results show that the accuracy of the depth map in edge areas goes up and its running time decreases. In addition, the lter improves the accuracy of edges in the depth map from Kinect sensor. As results, the quality of the rendering image is improved.

Secondary Electron Emission from Eiffusion Pump

Abstract: Secondary electron emission (SEE) properties of molecular substances, DC-704 (Dow Corning) and Octoil-S (CEC), were studied. Measurements were made on SEE coefficient and on inelastic reflection coefficient for a primary energy Ep in the range of 502000 eV at various thicknesses of DC-704 and Octoil-S films on tungsten. The maximum emission depth of true secondary electrons, λ's, are found to be about 40 and 70 A for DC-704 and Octoil-S respectively, and be independent of Ep for the range 4002000 eV. The efficiency of inelastically reflected primaries in producing true secondaries is 3 to 4 times larger than that of incident primaries. It is concluded that SEE properties of these molecular substances are similar to those of metals in several respects.