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This paper is an overview of a project concerned with “Early warning for torrential rainfall/tornado” under “Enhancement of Societal Resiliency against Natural Disasters,” which is one of eleven themes of the SIP (Cross-ministerial Strategic Innovation Promotion Program under the Council for Science, Technology and Innovation, the Cabinet Office, Government of Japan). The characteristics of the project are the development of a multi-parameter phased array weather radar (MP-PAWR) that enables the accomplishment of an accurate three-dimensional model of precipitation over 30 s within a 60 km radius. Various products developed ducts using MP-PAWR and other observations, and numerical predictions, are also discussed, with a demonstration experiment to provide early warnings for torrential rainfall and related disasters. For end users such as local governments and general citizens, the final goal of this project is the social implementation of these products.

Information of aerodynamic parameters of volcanic ash particles, such as terminal velocity, axis ratio, and canting angle, are necessary for quantitative ash-fall estimations with weather radar. In this study, free-fall experiments of volcanic ash particles were accomplished using a two-dimensional video disdrometer under controlled conditions. Samples containing a rotating symmetric axis were selected and divided into five types according to shape and orientation: oblate spheroid with horizontal rotating axis (OH), oblate spheroid with vertical axis (OV), prolate spheroid with horizontal rotating axis (PH), prolate spheroid with vertical rotating axis (PV), and sphere (Sp). The horizontally (OH and PH) and vertically (OV and PV) oriented particles were present in proportions of 76 % and 22 %, and oblate and prolate spheroids were in proportions of 76 % and 24 %, respectively. The most common shape type was OH (57 %). The terminal velocities of OH, OV, PH, PV, and Sp were obtained analyzing 2-D video disdrometer data. The terminal velocities of PV were highest compared to those of other particle types. The lowest terminal velocities were found in OH particles. It is interesting that the terminal velocities for OH decreased rapidly in the range 0.52 mm. The histogram of canting angles followed unimodal and bimodal distributions with respect to horizontally and vertically oriented particles, respectively. The mean values and the standard deviation of entire particle shape types were close to 0 and 10∘, respectively, under calm atmospheric conditions.

Radar variables of volcanic ash clouds are dependent on microphysical processes and can be expressed using physical parameters of volcanic ash particles, such as terminal velocity, axis ratio, and canting angle, which are necessary for quantitative ash-fall estimations. In this study, free-fall experiments of volcanic ash were accomplished using a two-dimensional video disdrometer under controlled conditions. Samples containing a rotating symmetric axis were selected and divided into five types according to shape and orientation, i.e., oblate and prolate spheroids with horizontally and vertically oriented axes and spheres. The horizontally and vertically oriented particles were present in proportions of 75.5 % and 21.6 %, and oblate and prolate spheroids were in proportions of 76.2 % and 23.8 %, respectively. The most common shape type was a horizontally oriented oblate spheroid (57.3 %). The terminal velocities were classified according to shape type. The terminal velocities of prolate spheroids (vertically oriented) particles were higher than those of oblate spheroids (horizontally). Terminal velocities were in the range 0.5 < volume–equivalent spherical particle diameter (D) < 1 mm for OH because of an increase in axis ratio and a sharp decrease in sample size from D < 0.7 mm. The axis ratios fell over a wide range, from 0 to 1.5, at D < 2 mm, but converged to 0.94 at D > 2 mm. The histogram of canting angles followed unimodal and bimodal distributions with respect to horizontally and vertically oriented particles, respectively. The mean values were close to 0° and the standard deviation for the entire particle shape types was close to that of raindrops (10°) under calm atmospheric conditions.

Preliminary results of quantitative analysis of volcanic ash clouds observed over the Sakurajima volcano in Kagoshima, Japan, were obtained by using weather radar and surface instruments. The Ka-band Doppler radar observations showed the inner structure of a volcanic ash column every two minutes after an eruption. Operational X-band polarimetric radar provides information on three-dimensional ash fall amount distribution. The terminal fall velocity of ash particles was studied by using optical disdrometers, together with the main specifications of observation instruments.

In the present study, the mechanical strength as well as the ionic conductivity of the scandia- and ytterbium oxide-codoped zirconia electrolyte is investigated during annealing. Based on the annealing effect on both properties, the degradation mechanism is discussed. The X-ray diffraction and Raman spectroscopic analyses confirmed that annealing enhanced the tetragonal phase content in the samples which initially contained the tetragonal phase. The samples with the rhombohedral phase showed no phase changes. The samples initially with the tetragonal phase showed a significant decrease in the conductivity but an increase in the strength whereas the samples with the rhombohedral phase generally showed no change and the ones with the cubic phase showed slight decreases in both properties. From above results, the conductivity degradation of the sample with the tetragonal phase was attributed to two causes: the formation of low conductive but transformable t -phase from the high conductive t ′-phase and the formation of t ′-phase from the t ″-phase. The annealing effect was little for the samples initially with rhombohedral phase and complex for the ones with cubic phase.

The correlation between compositions using particles of different two sizes and mechanical properties was studied experimentally. Spherical silica particles of 0.24 and 1.56 μm in diameter were compounded into a bisphenol A-type epoxy matrix at composition ratios ranging from 0 to 1.0 with a constant volume fraction, 0.30. Although varying the composition ratio of two-particle did not significantly affect the bending elastic modulus, the bending strength and fracture toughness were strongly dependent on the particle composition. The composition effect of different particle sizes on fracture toughness was clarified to have a difference from the one on bending strength, although elastic modulus varied according to volume fraction of particles.

We performed experimental and theoretical analyses that show a thin-walled cylinder with stiff ribs can be used as a structural element to improve or adjust energy absorption characteristics. We conducted impact crushing tests using several different cylinders with ribs. The experimental results showed that the axisymmetric and non-axisymmetric crushing modes were dependent on not only the cross-section size but also on the distances between the ribs. A critical distance between the ribs was found to exist for generating axisymmetric and non-asxisymmetric crushing modes and it was more than double the wavelength of axisymmetric wrinkles regardless of cylinder size. The mean crushing forces of the axisymmetric modes were found to be roughly 1.3 times larger than those of the non-axisymmetric modes. The theoretical results based on plastic hinge behavior showed good agreement with the experimental results. The effects of material and cylinder size on the crushing behavior of a cylinder with ribs were expressed using approximate mathematical equations. The critical distance between ribs for generating axisymmetric or non-axisymmetric crushing mode was also expressed approximately. Stiff ribs appropriately spaced in a cylinder were found to be effective in absorbing a large amount of energy with a short crushing deformation.

Mechanical properties of nano/micro-silica particles bidispersed epoxy composites were investigated based on experimental results. The composite specimens varied with different compositions of nano and micro-silica particles (240 nm and 1.56$m) were prepared with the constant volume fraction, 0.30. The thermo-viscoelastic properties for the composites and the neat epoxy measured in the temperature ranges from 123 K to 523 K and compared to theoretical results according to Lewis and Nielsen’s law with the maximum particle packing given by Ouchiyama and Tanaka’s model. In addition, fragility derived from the thermo-viscoelasticity measurements was used to characterize the strength and fracture toughness of the composites. From results, we found that the thermo-viscoelasticity of the composite was dependent on nano and micro-particles packing, and its strength and fracture toughness were effectively evaluated by fragility.

In this study, we propose a method to predict fracture initiation time for thermo-viscoelastic material by using master curves of stress intensity factors and fracture toughness, which are derived according to the time-temperature equivalence principle. As a concrete example, we analyzed a problem concerning a thermo-viscoelastic cylinder with a crack under steady or transient-isothermal temperature and crack length conditions. We show the process for predicting fracture initiation time. Based on the analysis results, we conclude that this method is useful for estimating crack propagation and is also available to solve various fracture problems dealing with thermo-viscoelastic materials.

This paper investigated the initiation and propagation characteristics of impact-induced damage in carbon-fiber-reinforced-plastic (CFRP) laminates with different stacking sequences and thicknesses under low-velocity impact. Impact force histories were measured with a drop-weight impact tester. A strain gauge was attached on the back face of CFRP laminates to measure exactly when a matrix crack on its back face was initiated. It was found from fractographic observation that impact-induced damage in CFRP laminates was initiated at the matrix crack on the back face of CFRP laminates due to bending deformation during impact. Finite element analysis was conducted using the impact forces derived from the experimental results of the impact test. Its results clarified that the tensile stress normal to the fiber on the back face of the specimen was the criterion to initiate impact damage in CFRP laminates.

The development characteristics of impact-induced damage in carbon-fiber-reinforcedplastics (CFRP) laminates were experimentally studied using a drop-weight impact tester. Five types of CFRP laminates were used to investigate the effect of stacking sequences and thicknesses. The efficiency of absorbed energy to impact energy was different for CFRP laminates with different stacking sequences or thicknesses. The DA/AE ratio of delamination area (DA) to absorbed energy (AE) was almost the same for CFRP laminates with the same stacking sequence regardless of the thickness. We found that the DA/AE ratio could be used as a parameter to characterize the impact damage resistance in CFRP laminates with different stacking sequences.

We discuss the effect of compositions of two sizes of silica particles on the thermo-viscoelastic properties of epoxy composites according to Lewis and Nielsen’s mixture law and its particle packing model. Epoxy composites containing varied composition ratios ΦSP of two sizes of spherical silica particles, 0.24 and 1.56 μm, were prepared at a fixed volume fraction (VP = 0.30). The thermo-viscoelastic properties of these composites and neat epoxy resin measured from 123 to 535 K were investigated using Lewis and Nielsen’s law with the maximum packing fraction of particles ϕmax of Ouchiyama and Tanaka’s model. Our results revealed that thermo-viscoelasticity was affected by the maximum packing fraction below the glass transition temperature Tg, and the mobility of matrix resin at T > Tg.

The effect of transverse impact on the buckling behavior of a column under axial compressive load was numerically investigated with finite-element analysis. An axially compressed column was subjected to transverse-impact that instantaneously reduced its structural stiffness. Due to this impact, the column lost its stability and buckled even when the axial load was lower than Euler's buckling load. A transverse-impact load like a half-sine wave with different peaks and durations was applied to the column. We found that the critical condition to generate buckling was determined by the external work of the transverse-impact load. The velocity of column deformation increased as the maximum load for transverse-impact increased. Therefore, deformation during the post-buckling process might be controlled by transverse-impact.

The effect of transverse impact on the buckling behavior of a column under axial impact loading was numerically investigated using finite element analysis. A column under axial impact was subjected to transverse impact to instantaneously reduce its structural stiffness. Absorption of the axial impact energy increased due to post-buckling deformation being enlarged by transverse impact, though the axial impact load decreased. The numerical results of the finite element analysis qualitatively proved the results of a previous experiment. A transverse impact applied almost simultaneously with an axial impact produced the highest energy absorption. The impulse of transverse impact seems to be the governing parameter when a transverse impact is applied just after an axial one. It is confirmed that a transverse impact could increase the axial energy absorption of a column without losing any structural stiffness or static strength.

We performed a nondestructive evaluation of micro-cracks in ceramic ferrules for optical fiber connectors by resonant ultrasound spectroscopy (RUS). The ferrules were cylinders 10 mm in length and 2.5 mm in diameter. The acceptable ferrules had no cracks or ones below 5 μm and the defective ferrules had cracks from 5 to 25 μm in length. The acceptable ferrules could be distinguished from the defective ones statistically, even those with cracks of 5 μm, by comparing the differences between the resonant frequencies for both specimens.

The effect of a transverse impact on the buckling behavior of a column under axial impact loading was experimentally investigated. A column under an axial impact was subjected to a transverse impact to instantaneously reduce the structural stiffness. It was found that the absorption of the axial impact energy increased due to the post-buckling deformation being enlarged by transverse impact, though the axial impact load decreased. The experiment showed that the time elapsed from the beginning of the axial impact to the transverse impact significantly influenced the energy absorption. A transverse impact applied simultaneously with an axial impact produced the highest energy absorption. To compare the efficiency of the present method, tests without a transverse impact on specimens that had dents were also conducted. It was confirmed that the present method could increase the energy absorption without loosing any structural stiffness or static strength.

We investigated the particle size effects on the fracture toughness of epoxy resin composites reinforced with spherical-silica particles. The silica particles had different mean particle diameters of between 1.56 and 0.24µm and were filled with bisphenol A-type epoxy resin under different mixture ratios of small and large particles and a constant volume fraction for all particles of 0.30. As the content with the added smaller particle increased, the viscosity of each composite before curing remarkably increased. We conducted the single edge notched bending test (SENB) to measure the mode I fracture toughness of each composite. The fracture surface with the small particle content exhibited more rough areas than the surface with larger particles. The fracture toughness increased below the small particle content of 0.8 and saturated above it. Therefore, near the small particle content of 0.8, the composite had a relatively low viscosity and a high fracture toughness.

We investigated the mode II fracture toughness (KIIc) with time and temperature dependence of the bisphenol A type of epoxy resin. We performed an asymmetric four-point bending test under various conditions of temperature and displacement rate. We found that KIIc strongly depended on the displacement rate and the temperature, even at room temperature. Moreover, it was governed by the time–temperature equivalence principle in regard to the fracture time. The time–temperature dependency of KIIc was similar to that of the loss modulus (E″), and the transition of brittle to ductile fractures occurred nearly simultaneously when E″ peaked. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 51–55, 2005

Resonant ultrasound spectroscopy (RUS) is based on the principle that mechanical resonant response of solids depends on its elastic moduli, shape and density. Elastic moduli or the other properties can be identified from resonant frequencies as inverse problem. In this study, the method to determine elastic moduli of a spherical specimen without information of resonant mode was described. We confirmed that resonant frequencies have to be measured under condition of free surface, and adequate number of resonant frequencies used in calculation needs enough number to include the sensitive mode to Poisson's ratio. By this method, we determined elastic moduli of BK-7 glass. The calculated frequencies from the elastic moduli determined by this technique had good agreement with the measured, the absolute accuracies for the Δf was less than 0.4%.

We investigated the fracture locus and the direction of the crack initiation under mixed mode I/II for epoxy resin at room temperature. In order to obtain them over a whole mode mixity, we conducted asymmetric bending tests. We examined four common fracture criteria to compare them with the experimental results. Based on our experimental results, we concluded that the relaxation effect on fracture toughness varies with the mode mixity, so the common fracture criteria for mixed mode could not be applied to the epoxy resin. In contrast, the crack initiation angle can possibly be determined independently of the relaxation effect.

We experimentally investigated compressive behaviors of a paper and a paper coated by polyethylene resin. The initial thickness of sheets of paper measured under a compressive stress of 4.5kPa was widely distributed in comparison with the basis weight, although the results based on the ISO 534 standard (under compressive stress of 100kPa) had relatively little dispersion. For compressive deformation, the thickness immediately decreased under low compressive stress, because the gap between fibers in the paper collapsed. After that, the variation of the thickness under higher compression was small due to the compression of fibers. We found that although the resin-coat layers did not have an insignificant effect on compressive compliance above 250kPa, the compliance of the coated paper was larger than that of uncoated paper.

We analyzed the thermal stress on a thermoviscoelastic hollow cylinder with temperature-dependent thermal properties with the finite difference method. It was gradually heated at the inner surface and the outer surface was kept at the initial temperature. The cylinder material was thermorheologically simple and had a temperature-dependent coefficient of linear thermal expansion, thermal conductivity, and thermal diffusivity (and/or specific heat). A bisphenol A–type epoxy resin was chosen as the thermoviscoelastic material of the cylinder for numerical analysis. Based on these results, we discuss the effects of thermoviscoelasticity and temperature-dependent thermal properties on the stress field.

We investigated the buckling behavior of a column subjected to a transverse impact during static axial compression in relation to structural energy absorption in an experiment. Either a steel bar or an acrylic bar was collided into an aluminum alloy column to apply different histories of the transverse impact load. The column was buckled by the transverse impact under force lower than axial Euler's buckling force. We found that the critical condition of buckling generation was determined by the kinetic energy of the impactor independent of the impact force history. The velocity of the column deformation increased as the transverse impact velocity increased even when the axial force was low. Therefore, the deformation during post-buckling process can be controlled by the transverse impact.

The time-temperature dependence of the fracture toughness of poly(phenylene sulphide) (PPS) resin was examined. The fracture toughness was measured at several deflection rates and ambient temperatures in a three-point bending test. On the basis of these experimental results, the master curve of fracture toughness was determined from the shift factor of the thermoviscoelastic characteristics. The time-temperature dependence equivalent law can be applied to the fracture toughness by conducting a fracture test at a variety of rapidly changing deflection rates. The results clearly showed that the fracture passes from brittle to ductile near the glass transition temperature, and that the fracture of PPS is strongly dependent on the thermoviscoelastic characteristics. Therefore, the fracture toughness can be predicted for a wide range of temperatures and over a long time span.

The relationship between the postcuring conditions and fracture toughness on three silica particulate-filled epoxy composites was investigated. The glass transition temperature, Tg, and the fragility parameter, m, derived from the thermo-viscoelasticity, were used to characterize the composites, which were postcured under various conditions. The glass transition temperature and fragility both depended on both of the curing conditions and the volume fraction of silica particles. The glass transition temperature increased with the postcuring time and temperature, while the fragility generally decreased as the volume fraction increased. There was no direct correlation between the glass transition temperature and fragility. The fracture toughness depended on both the glass transition temperature and fragility. The composites with a high glass transition temperature and low fragility had high fracture toughness. These results indicate that the glass transition temperature and fragility are useful parameters for estimating the fracture toughness of the silica particulate-filled epoxy composites. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2261–2265, 2002

The relationship between the postcuring conditions and the fracture toughness of a bisphenol A-type epoxy resin cured with acid anhydride was investigated. The glass transition temperature and fragility parameter, derived from the thermo-viscoelasticity, were used to characterize the epoxy resin postcured under various conditions. Relationship between these two parameters and the fracture toughness was then investigated, based on the fractography results of a microscopic roughness examination of a fractured surface. The values of the glass transition temperature and fragility greatly depended on the postcuring conditions. The glass transition temperature was approximately 400 K when the crosslinking reaction was saturated. The fragility was independent of the saturation of the reaction and varied between 50 and 180. The results of the fracture test and fractography examination showed that there was no direct correlation between the glass transition temperature, the fracture toughness, and the roughness. On the other hand, there was a correlation between the fragility, fracture toughness, and roughness when the glass transition temperature saturated (at 400 K). As the fragility decreased from 180 to 50, the fracture toughness increased from 0.6 to 1.1 MPa · m1/2 at the same glass transition temperature. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 10: 2266–2271, 2002

The relationship between the curing conditions and the time-temperature dependence of fracture toughness was investigated for bisphenol A epoxy resin. The glass transition temperature and Angell's fragility parameter, which are obtained from thermoviscoelasticity measurements, were used to characterize epoxy resins cured under various conditions. Examination of the fracture toughness at various temperatures and displacement rates showed that it depends on both temperature and time, and that it follows the time-temperature equivalence principle. The time-temperature dependence of the fracture toughness was greatly affected by the fragility parameter. The fracture toughness of the resin with a smaller fragility parameter increased from lower temperatures to the brittle-ductile transition temperature than that of the resin with a larger fragility parameter when their glass transition temperatures were approximately 400 K. It was also found that the brittle-ductile transition temperature did not depend on the fragility parameter. This means that epoxy resin with a smaller fragility parameter has better fracture characteristics than epoxy resin with a larger fragility parameter if their glass transition temperatures are approximately 400 K.

We investigated the damage characteristics in carbon fiber reinforced plastics (CFRP) laminates impacted by soft body and hard body projectiles launched by an air gun. Three kinds of silicone rubber were used as soft body projectiles to investigate the damage resulting from soft body impact that includes material non-linearity and large deformation. Plastic and metallic materials were used as hard body projectiles. From the C-scan images obtained with a scanning acoustic microscope after the tests, we found that the damage mechanism of CFRP laminates in the soft body and hard body impacts was the same. The maximum impact force for each projectile was computed based on the energy balance model and the fundamental hydrodynamics. From this analysis, we found that there is a critical impact force for the delamination initiation and that it is independent of the material properties of the projectiles.

Oxygen diffusion coefficients for YBa 2 Cu 3 O 7− δ (YBCO) ceramics were determined from an isotope-gas exchange measurement using the stable isotope 18 O as a tracer between 450°C and 700°C. During the experiments, the oxygen deficient value ( δ ) is kept constant by controlling the oxygen pressure of the reactor. The oxygen diffusion in YBCO ceramics is represented by a single equation D =7.8×10 −1 exp(−1.05 eV/ RT ) cm 2 /s for the various oxygen deficient specimens we examined. The present results suggest that the oxygen diffusion rate in YBCO does not depend on the oxygen deficiency.

A physically-based short-term rainfall prediction method, which uses a volume scanning radar, is extended so that it utilizes grid point values from a numerical weather prediction, namely GPV data, as supplementary information. It is noted that this extended method does not use predicted GPV rainfall data The conceptual rainfall model in the prediction method plays the role of bridging a gap between radar information and the numerical-weather prediction. This extended method is applied to a rainfall event which occurred in the Baiu season, in July of 1994. Results shows that for extended lead time of three and four hours, the prediction of expanding rainfall area was greatly improved.

It is found that oxygen ion conductor 0.88ZrO2−0.12Sc2O3 shows a discontinuous change in ion conductivity and a structural phase transition at around 650°C. The temperature dependence of ion conductivity shows a clear hysteresis at transition temperature. The crystal structure changes reversibly from rhombohedral to cubic at the transition temperature. The compound 0.88ZrO2− 0.12Sc2O3 exhibits a first-order phase transition to a fast oxygen-ion conductor. The high temperature phase with fast ion conductivity is stabilized in the low temperature region by the addition of a dopant such as Gd2O3.

We have fabricated a contact junction between an epitaxially grown YBa2Cu3O74 thin film and a polycrystalline Ba ?? xKxBiO3 thin film. This contact junction shows the typical I-V characteristics of quasi-particle tunneling which are observed for junctions consisting of electrodes having different superconducting energy gaps. From the I-V characteristics, the superconducting energy gap, 2Δ, is estimated to be 1.5 meV along the c-axis for YBa2Cu3O74 and 3 meV for Ba ?? xKxBiO3+ The 2Δ/kTc for the Ba ?? xKxBiO3 is about 3.5, which is equal to that derived from a boundary Josephson junction. These properties show that the contact boundary between YBa2Cu3O74 and Ba ?? xKxBiO3 works as the tunneling barrier.

The purpose of this study is to clarify the relationship between ionic conductivity and phase transformation of zirconia system codoped with scandium oxide Sc 2 O 3 and ytterbium oxide Yb 2 O 3 . Aiming to achieve high ionic conductivity as well as high mechanical strength, the authors have also investigated the relationship between phase transformation and mechanical strength. The results have been discussed with respect to both the conductivity and the mechanical strength. The Sc- and Yb-codoped zirconia (ZrO 2 ) used as samples in this study were prepared by a standard solid-state reaction. X-ray powder diffraction (XRD) method was used to determine the crystal structures of the sintered samples. To detect any phase change between room temperature and 1273 K, thermal mechanical analysis (TMA) was conducted. To determine oxygen-ion conductivity in a temperature range from 873 to 1273 K in air, impedance measurements were performed with alternating current (ac). Single-cell performance was confirmed under the condition of 26.2 Pa partial hydrogen pressure. Finally, to measure bending strength, three-point bending tests were performed with a universal testing machine. The results of XRD and TMA showed that codoping of Sc 2 O 3 and Yb 2 O 3 into ZrO 2 successfully stabilized the cubic phase when the average radius ratio of these two dopants in total was close to the ideal one for the eight-coordinate. The ac impedance measurement demonstrated that the cubic-phase stabilization achieved a high conductivity. Adequate amounts of dopants produced oxygen vacancies for high conductivity without complex defects: ZrO 2 system doped with 1 mol % of Yb 2 O 3 and 8 mol % of Sc 2 O 3 showed the highest conductivity at 1273 K and 0.30 S/cm. The bending strength decreased with increasing the content of doped Sc 2 O 3 from 7 mol % to 11 mol %, depending on the amount of the tetragonal phase, which contributes to strengthen materials. In the performance test, the ZrO 2 system stabilized with doping 1 mol % Yb 2 O 3 and 8 mol % Sc 2 O 3 with thickness of 2.16 mm showed maximum power density at 1273 K, that is, 210 mW/cm 2 . From all the above tests, we recommend that, based on electrical and mechanical considerations, 1Yb8ScSZ is the present best option for an electrolyte material for a solid oxide fuel cell.

The electrical responses to infrared radiation of La2-xSrxCuOy(100) and YBa2Cu3Oy(103) epitaxial films with various kinds of crsystal orientation are studied using modulated laser light.These films show apparently nonbolometric responses at temperatures below the transition regions which are strongly dependent on the bias current. The difference in the observed responsivity between these high-Tc materials and BaPb1-xBixO3 can be explained on the basis of nonequilibrium superconductivity.

The stability of an infinite-layer compound ACuO 2 (A = Sr,Ca) at high temperature was studied by molecular dynamics simulation. For SrCuO 2 the infinite-layer structure was well reproduced at 300 K. However inspection of the simulated structure revealed that oxygen ions displaced from initially planar CuO 2 layer to the c-direction by ±19 pm alternatively. This structure was stable up to 1200 K and transformed to an amorphous phase above 1300 K. For CaCuO 2 the infinite-layer structure was unstable even at 300 K. Simulations in which cation in A site was substituted revealed that large cation in A site is responsible for the stabilization of the structure, consistent with the experimental results.

When the Ultrasonic-Atomic Force Microscope (U-AFM) is used to form an image of a surface of a specimen having discontinuities, contrast of the specimen in the image is usually stronger than that of an image formed by a conventional Atomic Force Microscope (AFM). In this article, the mechanism of the contrast of the image obtained by the U-AFM was explained by theoretical analysis. A ceramic and metal jointed bar (Steel/Cu/Si3N4) was selected as a specimen for this study. The specimen was located on the surface of a disc transducer generating ultrasonic waves up to 500 KHz, and was vibrated, wherein its first resonant frequency was 133.43 kHz. Both stress and displacement of the specimen were analyzed by classical beam theory and the two-dimensional elasto-dynamic theory. Experimental U-AFM imaging analyses were also carried out to compare the results.

Using Raman spectroscopic analysis and the fractographical analysis, we investigated the relationship between the glass transition temperature, Tg, the fragility parameter, m, and the fracture toughness, KIc, of epoxy resin and composite. Tg and m derived from the thermo-viscoelasticity were used to characterize the epoxy resin and composite post-cured under various conditions. The Raman spectroscopic analysis showed that the Tg is directly related to the degree of cross-linking reaction of the epoxy resin and the matrix of composite. The fractography showed that m of the epoxy resin depends on the heterogeneous microstructure. The m of the composite was dominated by the volume fraction. KIc of the epoxy resin increased as m decreased when the Tg was saturated at approximately 400K. A composite with a high Tg and a low m had a high KIc value.

The high temperature cubic phase of Ba2 nr2O5 shows large ion conductivity. It is interestingto examine, if the cubic phase can be stabilized in the low temperature region (920 C) by making solid solution of another element. In the present study, we investigated the ion conductivity and the crystal structure of Ba2(In2-x.Mx)O5 system by substituting In site for element M such as Sc, Y, La, Ce, Nb, Ta etc. By substituting 3 mole % Nb for In, the transition temperature decreased by about 300 C. High temperature X-ray diffraction analysis shows the crystal structure changes from orthorhombic to cubic at this transition temperature. The effective elements which decreased the transition temperature were pentavalent or tetra valent elements such as Nb or Si ,Ce. The substitution In site for 20 mole percentage Nb stabilizes the cubic structure down to room temperature. Considering the transport number, the tetravalent element doping is very effective to stabilize the cubic phase of Ba2In2O5 without lose of excellent characteristic of pure Ba2ln2O5.