Search

Three-dimensional point clouds are becoming popular representations for digital archives of cultural heritage sites. The Borobudur Temple, located in Central Java, Indonesia, was built in the 8th century. Borobudur is considered one of the greatest Buddhist monuments in the world and was listed as a UNESCO World Heritage site. We are developing a virtual reality system as a digital archive of the Borobudur Temple. This research is a collaboration between Ritsumeikan University, Japan, the Indonesian Institute of Sciences (LIPI), and the Borobudur Conservation Office, Indonesia. In our VR system, the following three data sources are integrated to form a 3D point cloud: (1) a 3D point cloud of the overall shape of the temple acquired by photogrammetry using a camera carried by a UAV, (2) a 3D point cloud obtained from precise photogrammetric measurements of selected parts of the temple building, and (3) 3D data of the hidden relief panels recovered from the archived 2D monocular photos using deep learning. Our VR system supports both the first-person view and the bird’s eye view. The first-person view allows immersive observation and appreciation of the cultural heritage. The bird’s eye view is useful for understanding the whole picture. A user can easily switch between the two views by using a user-friendly VR user interface constructed by a 3D game engine.

The recent development of 3D scanning technologies has made it possible to quickly and accurately record various 3D objects in the real world. The 3D scanned data take the form of large-scale point clouds, which describe complex 3D structures of the target objects and the surrounding scenes. The complexity becomes significant in cases that a scanned object has internal 3D structures, and the acquired point cloud is created by merging the scanning results of both the interior and surface shapes. To observe the whole 3D structure of such complex point-based objects, the point-based transparent visualization, which we recently proposed, is useful because we can observe the internal 3D structures as well as the surface shapes based on high-quality see-through 3D images. However, transparent visualization sometimes shows us too much information so that the generated images become confusing. To address this problem, in this paper, we propose to combine “edge highlighting” with transparent visualization. This combination makes the created see-through images quite understandable because we can highlight the 3D edges of visualized shapes as high-curvature areas. In addition, to make the combination more effective, we propose a new edge highlighting method applicable to 3D scanned point clouds. We call the method “opacity-based edge highlighting,” which appropriately utilizes the effect of transparency to make the 3D edge regions look clearer. The proposed method works well for both sharp (high-curvature) and soft (low-curvature) 3D edges. We show several experiments that demonstrate our method’s effectiveness by using real 3D scanned point clouds.

We propose a high-quality transparent visualization method suitable for large-scale laser-scanned point clouds. We call the method “stochastic point-based rendering (SPBR),” which is based on a novel stochastic algorithm. SPBR enables us to clearly observe the deep interior of laser-scanned 3D objects with the correct feeling of depth. The high quality of SPBR originates from the effect of “stochastic noise transparentization,” which is an effect to make the measurement noise transparent and invisible in the created images. We mathematically prove that this effect also makes the created transparent images coincide with the results of the conventional methods based on the alpha blending, which is time-consuming and impractical for large-scale laser-scanned point clouds. We also demonstrate the effectiveness of SPBR by applying it to modern buildings, cultural heritage objects, forests, and a factory. For all of the cases, the method works quite well, realizing clear and correct 3D see-through imaging of the laser-scanned objects.

In this paper, we propose a method to visualize large-scale colliding point clouds by highlighting their collision areas, and apply the method to visualization of collision simulation. Our method uses our recent work that achieved precise three-dimensional see-through imaging, i.e., transparent visualization, of large-scale point clouds that were acquired via laser scanning of three-dimensional objects. We apply the proposed collision visualization method to two applications: (1) The revival of the festival float procession of the Gion Festival, Kyoto city, Japan. The city government plans to revive the original procession route, which is narrow and not used at present. For the revival, it is important to know whether the festival floats would collide with houses, billboards, electric wires, or other objects along the original route. (2) Plant simulations based on laser-scanned datasets of existing and new facilities. The advantageous features of our method are the following: (1) A transparent visualization with a correct depth feel that is helpful to robustly determine the collision areas, (2) the ability to visualize high collision risk areas and real collision areas, and (3) the ability to highlight target visualized areas by increasing the corresponding point densities.

Ultrasonic spray pyrolysis method to synthesize porous submicron particles of solid oxide fuel cell (SOFC) electrode materials was developed in which citric acid is added in a precursor solution. This citric acid-addition ultrasonic spray pyrolysis (CA-USP) method was then used to synthesize NiO-Gd0.1Ce0.9O1.95 (GDC) particles for SOFC anodes and La0.8Sr0.2Co3 (LSC) and La0.8Ca0.2MnO3 (LCM) particles for SOFC cathodes. The synthesized particles were submicron-sized, porous, and spherical, and had a sponge-like structure. Energy dispersive X-ray spectrometry images of the synthesized NiO-GDC particles revealed that Ni, Ce, Gd, and O were uniformly distributed within individual particles. NiO-GDC and LCM particles with sponge-like structure were not crushed by a 2-h ball mill grinding test. The formation process of the sponge-like structure was clarified by synthesizing GDC particles at various furnace temperatures between 473 and 1273 K.Copyright 2014 American Association for Aerosol Research

A new ultrasonic spray pyrolysis method, called carbon nanoparticle-addition ultrasonic spray pyrolysis (CNA-USP), is developed to synthesize nanoparticles of electrolyte material for solid oxide fuel cell applications. In CNA-USP, carbon nanoparticles are added in a precursor solution. First, Gd0.1Ce0.9O1.95 (GDC) particles were synthesized from an aqueous solution of Ce(NO3)3 6H2O and Gd(NO3)3 6H2O by using the CNA-USP method. The resulting synthesized GDC particles were agglomerated, porous, primary particles on the order of 10 nm in diameter. EDX images revealed uniform distributions of Ce, Gd, and O in these porous particles. Then, these agglomerated, porous submicron GDC particles were ground into primary nanoparticles by ball milling for 24 h. The average diameter of the ground GDC nanoparticles was about double of their average crystallite size.Copyright 2014 American Association for Aerosol Research

We have discovered new members of the Pb-based 1222 layered cuprates containing sulfur of (Pb0.75S0.25)Sr2(RE1.6Ce0.4)Cu2Oz with RE = Sm, Gd, Dy, and Ho. All the samples are of almost-single 1222 phase. From the ρ–T and χ–T measurements, they are found to be superconductors after annealing under 125 atm O2 atmosphere at 400 °C. Among them, the sample with RE = Gd is found to show superconductivity at the highest temperature of 30 K.

Thin films of the perovskite Gd0.5Sr0.5CoO3 (GSCO), a cathode material, were fabricated by pulsed laser deposition methods. Two kinds of single-crystal (100) 8-mol% Y2O3 doped zirconia (YSZ) were used as substrate: with one surface polished and with both surfaces polished. GSCO thin films deposited on YSZ substrates with a polished surface had a columnar polycrystalline structure. The surface structure of the GSCO thin film was strongly affected by the substrate surface structure. The GSCO films on the unpolished YSZ were much rougher. From impedance measurements, because of the large surface contact area, the symmetrical cell with GSCO thin film deposited on YSZ with only polished one surface exhibited at a temperature of 400°C small resistances that were five times lower than the resistances of the cell which contained a GSCO thin film deposited on YSZ with both surfaces polished.

A new family of the Pb-based layered cuprate with the 1222 structure has been synthesized in the (Pb,S)Sr2(RE,Ce)2Cu2O z (RE=Pr, Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm, and Y) system. The almost-single phase samples are obtained for x=0.25 and y=1.0 in the composition of (Pb1−x S x )Sr2(RE2−y Ce y )Cu2O z . Each of the samples has the crystal structure with a tetragonal symmetry. Both of the lattice parameters a and c are decreasing with the decrease of the ionic radius of RE element. Among these samples, the sample with RE=Er has the smallest resistivity in the whole temperature range and the slope of the resistivity versus temperature is the most gentle. Despite annealing under O2 atmosphere at high-pressure of 121 atm, this sample is a semiconductor with the transport process characteristics of three-dimensional variable range hopping conduction. Then the samples of RE=Er with smaller y are investigated for the composition of (Pb0.75S0.25)Sr2(RE2−y Ce y )Cu2O z , the sample with y=0.4 is found to show an onset of resistivity drop phenomenon at about 11 K with the decrease of temperature. Moreover, we also discover that the samples of RE=Ho with y=0.4 show an onset of the resistivity dropping at over 20 K and zero resistivity at 13 K. From these results, the present (Pb0.75S0.25)Sr2(RE2−y Ce y )Cu2O z system is considered to be a new family of the Pb-based superconducting cuprates with the 1222 structure.

We have synthesized new Pb-based 1222 cuprates containing sulfur in the (Pb0.75S0.25)Sr2(Eu2.0−x Ce x )Cu2O z system. X-ray diffraction study shows that almost the single 1222 phase samples can be obtained for a considerable wide area of 0.3≤x≤1.2 in the composition of (Pb0.75S0.25)Sr2(Eu2.0−x Ce x )Cu2O z . Next, the sample with x=0.4 after annealing under high-pressure O2 is discovered to show an onset of the resistivity drop at about 31 K and to show an onset of diamagnetic signal at about 29 K. These phenomena clearly indicate that the sample is a new superconductor.

In this study, we used the general dynamic equation (GDE) for aerosols, combined with particle charging by positive ions and electrons, to simulate particle generation in laser ablation plasmas. The population balance equations based on Brownian coagulation and diffusion charging theory were represented by using a discrete-sectional model. The temporal evolution of the particle size distribution was simulated at three different initial number concentrations of neutral monomers, positive ions and electrons, as well as at two different gas pressures. The simulated average particle size increased with time and with increasing initial concentration of neutral monomer and gas pressure. The particle growth was affected by the particle charging when both number ratios of positive ion to neutral monomer and of electron to neutral monomer are higher than 0.1. Simulated particle size distributions were compared with SEM images of particles collected at different sampling points and gas pressures in actual plasmas operating at conditions similar to those simulated. Changes of particle size with increasing distance between the target and the sampling point and with increasing the pressure were well reproduced by simulations. However, particle diameters calculated were much smaller than SEM images because physical values, such as, initial concentrations of monomer, positive ions and electrons and the recombination probability of electron and positive ions, used in calculations were invalid.

New Pb-based 1222 cuprates containing phosphorus have been synthesized in the (Pb0.75P0.25)Sr2- (RE2–x–yCexSry)Cu2Oz (RE = Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm, Yb, and Y) systems. The almost-single phase samples are obtained for 0.5≤x≤1.0 and y=0.1 in the cases of RE = Nd, Dy, Ho, Er, Tm, Yb and Y, while for 0.3≤x≤1.0 and y=0.1 in the cases of RE = Sm, Eu and Gd. The samples crystallize in a tetragonal lattice, the lattice parameters a and c are decreasing with the decrease of the ionic radius of the RE element. Even after annealing under 143 atm O2 atmosphere at 400 °C, almost all the samples with the common values x=0.5 and y=0.1 are semiconductors with a transport process followed by three-dimensional variable range hopping. However, the samples of RE = Sm, Eu and Gd, which are of almost single 1222 phase, even for x=0.3 and y=0.1, show superconductivity with the onsets at about 25 K, 20 K and 22 K, respectively. Through this study, we find very important procedure for discovery of new superconducting 1222 compound.

We previously reported on the synthesis of new Pb-based 1222 superconductor containing phosphorus in the (Pb0.75P0.25)Sr2(Eu1.9−xCexSr0.1)Cu2Oz system. Recently, we have discovered new members of the Pb-based 1222 superconductor containing phosphorus in the (Pb0.75P0.25)Sr2(Ln1.9−xCexSr0.1)Cu2Oz (Ln=Sm and Gd) systems. In each system, it is found that the samples of almost the single 1222 phase can be obtained for a wide composition area of 0.3≤x≤1.0. After annealing under 143 atm O2 atmosphere at 400 °C, each sample of Ln=Sm and Gd with x=0.3 is found to show an onset of resistivity-drop at about 28 K and at about 24 K, respectively. Moreover, each samples of Ln=Sm and Gd is found to show an onset of diamagnetic signal at about 25 K and about 22 K, respectively. From these facts, these samples of Ln=Sm and Gd are found to be new members of the Pb-based 1222 superconductor containing phosphorus.

A Mixing-type Bipolar Charger using Corona-discharge at High Pressure (MBCCHP) is subjected to both theoretical and experimental evaluation. In theoretical studies, the charging model for the MBCCHP is developed to determine the influences of the residence time tR, the number ratio of negative ions to positive ions N−/N+, and the number ratio of particles to bipolar ions n0/NB (where NB = N+ + N−) on the charge distribution. The charge distribution recorded experimentally at various values of n0/NB and N−/N+ is compared with theoretical results. The comparisons indicate that the theoretical results can be used to adequately explain well the experimental data. Both sets of results demonstrate that the MBCCHP is capable of generating equilibrium charge distributions of aerosol particles within errors of 10%. The diameter of the particles ranges between 10–500 nm and the particle number concentration n0 is less than 3.0 × 1012 m−3 under operating conditions of 0.5 > tR > 0.1 s, with a frequency >100 Hz, a voltage of 9.0 kV0–p, and a high-pressure ionizer operating at 0.4 MPa.

We already reported on the synthesis of new Pb-based 1212 layered cuprates containing sulfur in the (Pb0.75S0.25)Sr2(Y,Ca)Cu2Oz system. There none of the samples showed superconductivity until after annealing under high O2 pressure. More recently, we have discovered that the samples could be substituted by Ba for Sr up to x=0.6 in the composition of (Pb0.75S0.25)(Sr2−xBax)(Y0.4Ca0.6) Cu2Oz. Then if the Ba-substitution is performed for Sr, some of the almost-single phase samples are found to show resistivity drops and magnetic anomalies without annealing under high O2 pressure. Among the samples, a sample with the nominal composition of (Pb0.75S0.25)(Sr1.5Ba0.5)(Y0.4Ca0.6) Cu2Oz is found to show the highest onset temperatures of a resistivity drop at about 35 K and a magnetic anomaly at about 31.5 K. These are higher than the highest values for the superconducting Ba-free sample of (Pb0.75S0.25)Sr2 (Y0.4Ca0.6)Cu2Oz which was annealed under high O2 pressure.

The Pb-based 1212 compounds containing phosphorus were already discovered by us in the (Pb,P)Sr2(Y,Ca)Cu2Oz system. Among the almost-single phase samples, a sample with the nominal composition of (Pb0.75P0.25)Sr2(Y0.4Ca0.6)Cu2Oz was a superconductor with the highest Tc of 38 K in the system. Recently, we have been investigating on substitution effect of Ba for Sr on superconductivity in the (Pb0.75P0.25)(Sr2−xBax)(Y0.4Ca0.6)Cu2Oz system. As a result, it is found that the almost–single 1212 phase samples are obtained in the composition area of 0.0≤x≤0.4. In this area, with increase of x, the lattice parameters a,c and the cell volume V are found to be gradually increasing. This finding can be considered to show that larger Ba2+ ions certainly occupied the Sr-sites in the sample. However, we obtain such interesting results as that the Tc value is not so enhanced by the substitution in comparison with that of the sample of x=0.0, and that the maximum value of Tc was 40 K for x=0.2 and 0.3 at the best.

New Pb-based 1212 layered cuprates containing sulfur have been synthesized in the (Pb0.75S0.25) Sr2 (Y1−xCax) Cu2Oz system. X-ray diffraction analysis shows that the almost single-phase samples are obtained within a region of 0.0≤x≤0.5. The crystal structure of each sample has a tetragonal symmetry with the typical lattice constants a=0.3837 nm and c=1.186 nm. As Ca content x is increasing, the semiconductor-like behavior is suppressed. But after only annealing under ambient O2 pressure, none of the samples show any trace of superconductivity. On the other hand, when the samples are annealed under high O2 pressure of about 13.6 MPa, they show resistivity dropping phenomenon in a region of 0.5≤x≤0.7. Among them, the lowest resistivity sample with x=0.6 has an onset temperature of the resistivity dropping at about 22.5 K. Moreover, this sample shows a diamagnetic signal at about 21.5 K. These phenomena are attributed to superconductivity.

A small mixing-type unipolar charger for nanoparticles (SMUC) was developed to increase the charging efficiency and throughput by using a small charging chamber (0.5 cm 3 ) to reduce particle loss caused by electrostatic dispersion. The two main components of the SMUC are a high-pressure corona ionizer (HPC Ionizer) in which high concentration unipolar ions are generated, and a charging chamber in which the unipolar ions are mixed with nanoparticles without an external electric field. The charging performance of the SMUC was evaluated experimentally by measuring the charging ratio fc and the penetration ratio fp . For positive charging in the particle size range of 5–40 nm, fc + = 0.91–0.95 and fp + = 0.71–0.90, at an ion concentration of Ng + = 5.25 10 9 ions/cm 3 and a charging time t R = 0.025 s. For negative charging, f – c = 0.74–0.93 and fp – = 0.73–0.85, at Ng – = 6.24 × 10 9 ions/cm 3 and tR = 0.025 s. Based on these results, the extrinsic charging efficiency defined as fe = fc ×fp /fd (where fd i...

We previously reported on discovery of new Pb-based 1232 cuprate containing boron in the (Pb0.5B0.5)Sr2(Er3−x−yCexSry)Cu2Oz system. Recently, a new member of the Pb-based 1232 cuprates containing boron has been synthesized in the (Pb0.5B0.5)Sr2(RE3−x−yCexSry)Cu2Oz systems (RE=Ho, Tm, and Y). In each system, almost the single 1232 phase samples are found to be obtained for the composition area of x=1.7–1.9 and y=0.2, and the sample with x=1.7 is found to show the smallest resistivity. Despite of annealing under 142 atm O2 atmosphere at 400 °C for 4 h, the sample with x=1.7 in each system is a semiconductor with the transport process followed by a three-dimensional variable range hopping conduction. Moreover, it is found that the sample with RE=Ho shows magnetic anomalies at two temperatures of about 11 and 16 K, and the sample with RE=Y shows a diamagnetic signal at about 8 K, respectively.

New Pb-based 1212 compounds containing phosphorus have been discovered in the (Pb1−yPy)Sr2(Y1−xCax)Cu2Oz system; almost the single 1212 phase samples can be obtained for the composition range of 0.0≤x≤0.6 and y=0.25. The crystal structure for each sample has a tetragonal symmetry with the typical lattice parameters a=0.3828 nm and c=1.182 nm. Among them, the sample with x=0.6 and y=0.25 shows the onset of resistivity drop at about 39 K and zero-resistivity at about 17 K. Moreover, the sample shows a diamagnetic signal at about 38 K. These phenomena are found to originate from superconductivity with the bulk feature.

New Pb-based layered cuprates containing boron with the 1232 structure have been synthesized in the (Pb0.5B0.5)Sr2(Er3−x−y Ce x Sr y )Cu2O z system. Nearly the single 1232 phase samples are obtained for the nominal composition of 1.6≤x≤1.9 and y=0.2. A sample with the composition of (Pb0.5B0.5)Sr2(Er1.2Ce1.6Sr0.2)Cu2O z shows resistivity-dropping phenomenon below 10 K and it shows a diamagnetic signal at about 9.0 K, though the superconducting volume fraction is very small. From these results, the sample may well be a new Pb-based superconductor with the 1232 structure.

Possibility of boron substitution for Bi and the substitution effect on superconductivity is investigated for the Bi-2212 phase of Bi-Sr-Ca-Cu-O. From X-ray diffraction study, it is found that samples in the (Bi2−xBx)Sr2CaCu2Oz system are mainly of the single 2212 phase in a composition range of 0.0≤x≤0.6, and both of the lattice parameters a and c change with increasing x up to 0.6. From measurements of the magnetic susceptibility and the electrical resistivity, the superconducting transition temperature is found to increase up to 0.6 with increasing x. These results are considered to show that boron is substitutable for Bi up to x=0.6 in the (Bi2−xBx)Sr2CaCu2Oz system and that the boron substitution causes the number of hole-carriers to decrease in this system.

An aerosol neutralizer called the Mixing-type Bipolar Charger using Corona-Discharge at High Pressure (MBCCHP) was developed. In the MBCCHP, a corona discharge (High-Pressure Corona Ionizer; HPC Ionizer) induced by high frequency voltage (>100 Hz) at high pressure (>0.2 MPa) is used to generate bipolar ions at high concentration (1–3 × 109 ions/cm3) that are then mixed with aerosol particles flowing in a charging chamber where no external electric field is present. The charging performance of the MBCCHP was evaluated by comparing the measured and theoretical number ratios of positively and negatively charged particles to the total number of particles, and by comparing those of negatively charged to positively charged particles for an equilibrium charge distribution. The theoretical and measured results agreed well in the particle size range of 5–80 nm. Particle loss in the MBCCHP for the size range of 5–100 nm was less than 15%, and particle generation from the electrode due to spattering or from the carr...

We previously reported on the discovery of new Pb-based 1222 cuprates containing boron in the (Pb0.5B0.5)Sr2(RE2−x−y Ce x Sr y )Cu2O z (RE = Pr, Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm, Yb, and Y) systems. However, none of the cuprates was a superconductor, but a semiconductor with the conduction process of a three-dimensional variable range hopping at low temperatures, despite annealing under O2 atmosphere at 100 atm and 400 °C. Recently, we have discovered that some samples showed superconductivity in the (Pb0.5B0.5)Sr2(Y1.9−x Ce x Sr0.1)Cu2O z system. Among them, the sample with x=0.45 shows the highest zero resistivity temperature at about 10 K and it shows a diamagnetic signal starting at abut 16 K with lowering temperature. The superconductivity is considered to originate from the 1222 phase.

New superconducting layered cuprates of the 1212 phase have been synthesized in the (Pb 0.5 B 0.5 )(Sr 2− x Ba x )(Y 1− y Ca y )Cu 2 O z system. X-ray diffraction study shows that the almost-single phase samples are obtained within a region of 0 ⩽ x ⩽ 0.6 and 0 ⩽ y ⩽ 0.6. Then, the sample with x = 0.5 and y = 0.6 among them is found to have the maximum superconducting transition temperature of about 45 K. The crystal structure of this sample has a tetragonal symmetry with the lattice parameters of a = 0.3826 nm and c = 1.195 nm.

New Pb-based layered cuprates with the 1222 structure have been synthesized in the (Pb0.5B0.5)Sr2 (RE2−x−yCexSry)Cu2Oz (RE = Pr, Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm, Yb, and Y) systems. The almost-single-phase samples in the systems can be obtained for a nominal composition of x=0.7 and y=0.1. The crystal structure of the samples has a tetragonal symmetry, the lattice parameters of a and c are increasing with increasing the ionic radius of RE element. Despite treatment under high O2 pressure of 100 atm, the samples are semiconductors with the transport process characteristic of three-dimensional variable range hopping conduction.

We have synthesized the Ru-1232 compounds of RuSr 2 (Nd 1− x Dy x Ce 1.8 Sr 0.2 )Cu 2 O z . Nearly-single phase samples are found to exist in the x range from 0.2 to 0.5. All samples are semiconductors. Among them, the sample with x = 0.4 has the smallest resistivity. Though the sample is annealed under high-pressure O 2 atmosphere at 143 atm, it does not exhibit any anomaly resulting from superconductivity of the Ru-1232 phase down to 4.2 K. From the result of the resistivity measurements, the transport process is expected for the sample to be followed by a three-dimensional variable range hopping conduction.

Bi-based superconducting compounds with the 2222 structure has been already synthesized in the Bi2Sr2- (Ln1−xCex)2Cu2O10+y (Ln = Sm, Eu, and Gd) systems. One of the characteristics of these compounds is the existence of the fluorite-like (Ln1−xCex)2O2 block between two CuO5 pyramids in the crystal structure. The tetravalent ions of Ce4+ are reported to be necessary to stabilize the 2222 structure. Recently, we have discovered that the Bi-2222 phase could be composed in the Bi2Sr2(Ln2−xZrx)Cu2Oz (Ln = Sm, Eu, Gd, and Dy) systems, where Zr4+ is used as a new tetravalent ion stabilizing the 2222 structure in stead of Ce4+. In the new system, nearly single 2222 phase samples have been obtained at the nominal composition of x=0.5 (Ln = Sm, Eu, and Gd) and in the range of 0.1≤x≤0.3 (Ln = Dy). Among them, the sample with Ln = Gd has the smallest resistivity at 273 K. But it is a semiconductor, and the conduction process at low temperatures is assumed to be followed by a two-dimensional VRH. The experimental results for the Gd samples with a partial substitution of Pb for Bi in the Bi2Sr2(Gd2−xZrx)Cu2Oz system are also reported.

We propose the idea of d-dot, where a d-wave superconducting dot is embedded in s-wave matrix. Spontaneous half vortices should appear in the four corners of the d-dot [M. Kato, M. Ako, M. Machida, T. Koyama, T. Ishida, Physica C 412–414 (2004) 352; M. Ako, M. Kato, M. Machida, T. Koyama, T. Ishida, Physica C 412–414 (2004) 544; M. Fujii, T. Abe, H. Yoshikawa, S. Miki, S. Kawamata, K. Satoh, T. Yotsuya, M. Kato, M. Machida, T. Koyama, T. Terashima, S. Tsukui, M. Adachi, T. Ishida, Physica C 426–431 (2005) 104]. Symmetric geometry and the fourfold symmetry of the d-dot would be suitable as a building block for constructing the novel physical systems. The phase dynamics of a closed 0–π junction, which can be realized in a small d x 2 - y 2 -dot, is mapped on a quantum two-level system when the system size is small enough. Using two-component Ginzburg–Landau equation, we study the physical properties of d-dots systematically. We prepare epitaxial YBa2Cu3O7 (YBCO) films of thickness 100 nm on SrTiO3 substrates using a laser ablation apparatus. The d-dot is fabricated by a photolithography, electron beam lithography EB and an electron cyclotron resonance (ECR) etching, a focused ion beam microscope, and a lift-off technique. Local vortex profile is investigated using a SQUID microscope when d-dot is cooled in zero field.

When a d-wave superconducting dot (d-dot) is embedded in an s-wave superconductor matrix, a half flux quantum vortex is expected to appear spontaneously at four corners of the d-dot without applying an external magnetic field. First, we have prepared c -axis oriented YBa 2 Cu 3 O 7 (d-wave superconductor) thin films by pulsed-laser ablation deposition on c -axis oriented SrTiO 3 single-crystal substrates. We have fabricated resist-coated YBa 2 Cu 3 O 7 square islands by using an electron beam lithography and an electron cyclotron resonance etching. Then, we have deposited Pb (s-wave superconductor) film on the fabricated YBa 2 Cu 3 O 7 thin film, and removed extra Pb and resist films on the YBa 2 Cu 3 O 7 islands by a lift-off technique. Magnetic field distribution on superconducting d-dot has been measured by using a SQUID microscope in zero fields.

An experimental system employing a drift tube ion mobility spectrometer/mass spectrometer (DT-IMS/MS) and a cluster-differential mobility analyzer with Faraday cup electrometer (C-DMA/FCE) was developed for the study of ion-induced nucleation. Using this, both the time scales and size scales of ions to be measured can be extended significantly. The system offers the potential for tracing the entire process of ion-induced nucleation initiated by the radiative ionization of air. The main processes are the formation of stable cluster ions and their growth to nanometer-sized ultrafine particles. Negative ions and negatively charged nano-particles generated by α -ray radiolysis in SO 2 / H 2 O / air mixtures were examined. High-resolution mobility spectra in which ions are distributed in the relatively high mobility range of 2.1– 1.5 cm 2 V - 1 s - 1 were obtained by DT-IMS/MS. Alternatively, more aged ions with mobilities as low as 0.05 cm 2 V - 1 s - 1 were observed in the C-DMA spectra. The differences between both spectra reflect the nature by which cluster ions grow into nano-particles. In addition to mobility measurements, mass spectra of ions can be obtained by DT-IMS/MS, which allows the identification of nucleating ions and relevant ion chemistry to be investigated. In the mass spectra at low SO 2 and H 2 O concentrations, SO 2 - , SO 3 - , SO 4 - , and SO 5 - were observed as major ions, indicating that SO 2 is preferentially ionized by ion–molecule reactions with primary negative ions. When the concentrations of SO 2 and H 2 O were increased, HSO 4 - and HSO 4 - · H 2 SO 4 ions became prominent, suggesting that the oxidization of SO 2 into H 2 SO 4 is enhanced, probably due to the enhanced production of OH radicals by ion–molecule reactions involving H 2 O . This suggests that the role of SO 2 in particle formation differs depending on the concentrations of SO 2 and H 2 O . At low SO 2 and H 2 O concentrations, SO 2 tends to form core ions that lead to ion-induced particle formation, whereas more SO 2 molecules are transformed into gaseous H 2 SO 4 and homogenous nucleation involving H 2 SO 4 and H 2 O is enhanced at higher concentrations of SO 2 and H 2 O .

Synthesis of the Bi-2212 compound in the Bi-Sr-Ce-Cu-O system has been already known. But, there has been no report on superconductivity of the compound yet. We have prepared many Bi-2212 samples partially substituted by Pb for Bi in the Bi-Sr-Ce-Cu-O system. The nominal composition is (Bi2− y Pb y )Sr2(Sr1− x Ce x )Cu2O z . Then, we have investigated possibility of superconductivity for the samples. As a result, we find that a sample with nominal composition of x=0.23 and y=0.1, which is of almost the single 2212 phase, shows an anomaly at about 70 K in addition to temperature dependence of the resistivity like a semiconductor. Furthermore, the sample also shows a decrease of magnetic susceptibility starting at about 70 K with decreasing temperature. These experimental results can be considered to result from superconductivity of the 2212 phase in the Bi(Pb)-Sr-Ce-Cu-O system.

A charged nanodroplet generator using a sonic-jet ionizer was developed, and the size distributions and currents of ions and charged nanodroplets generated were measured. The sonic-jet ionizer produced O − 2 (H 2 O) n ions with a high density of 10 9 −10 10 cm −3 . When tetraorthosilicate (TEOS) and H2O vapors were added in the oxygen gas, the generator formed negatively charged nanodroplets with an average diameter of 1.3-1.8 and 1.3 nm, respectively. SiO 2 nanoparticles synthesized from the charged TEOS nanodroplets were non-agglomerated. The size distributions measured at various furnace temperatures indicated the formation mechanism of the nanoparticles was ion-induced nucleation. To investigate sterilization effects of negatively charged H 2 O nanodroplets, yeast fungi were exposed to the gas flow from the charged nanodroplet generator. Survival rates of yeast were clearly reduced by the discharge.

There have been no report about synthesis of the Bi-2212 compound in the Bi–r–La–Cu–O system. We have succeeded in synthesizing the Bi-2212 compound by partial substitution of Pb for Sr and/or Bi in the Bi–Sr–La–Cu–O system. Two samples of nearly the single 2212 phase have been obtained at a nominal composition of Bi1.5Pb0.5Sr2.5La0.5Cu2O z . Both of the samples crystallize in a psedotetragonal lattice, and their lattice parameters are a = 0.5476 nm and c = 3.085 nm or a = 0.5479 nm and c = 3.055 nm. They are both superconductors. The sample with longer lattice parameter c shows an onset of the resistivity drop and zero resistivity at higher temperatures of about 40 K and about 13 K, respectively. This sample also shows a diamagnetic signal starting at about 35 K with lowering temperature.

The Ru-1232 compounds have been synthesized in the (Ru1−xNbx)Sr2(GdCe1.8Sr0.2)Cu2Oz system, and effects of Nb substitution for Ru on superconductivity and ferromagnetism of the Ru-1232 compounds have been investigated. First, X-ray powder diffraction study shows that nearly the single 1232 phase samples can be obtained in the x composition range from 0.0 to 0.3. Then, from the electrical resistivity study, it is found that each of the samples shows resistivity dropping phenomenon at two temperatures of Tcl and Tch, which originates from superconductivity of the Ru-1232 phase and the Ru-1222 one, respectively. Both of the starting temperatures are lowering with increasing Nb content x. Lastly, from the magnetic susceptibility study, it is found that superconducting transition temperature Tc is 20 K for the Ru-1232 sample with x = 0.0 and the ferromagnetic transition temperature Tm is about 90 K. This study also shows that both of the values of Tc and Tm become low with increasing x from 0.0 to 0.3.

Particle formation mechanisms in nanoparticle synthesis by ionization chemical vapor deposition (CVD), in which source gases are ionized before being fed into the reactor, were investigated experimentally. First, nonagglomerated nanoparticles were formed from a tetraethylorthosilicate (TEOS)/O 2 mixture ionized with a sonic-jet ionizer at various furnace temperatures, T f, and TEOS concentrations, N TEOS. Then, the electrical mobility of the nanoparticles and ions were measured using a differential mobility analyzer combined with a Faraday cup electrometer, and the particle number concentration by a condensation nucleus counter. Measurements at 293 ≤ T f ≤ 1173 K and 0 ≤ N TEOS ≤ 1.38 × 10 −5 mol/l showed that (a) negative TEOS and TEOS cluster ions were formed at T f = 293 K, (b) gas-phase intermediates forming nanoparticles were formed at T f ≥ 673 K, (c) for T f = 873 K condensation of the intermediates onto ions (i.e., ion-induced nucleation) started at N TEOS ≥ 4.48 × 10 −7 mol/l, and (d) the growth ...

Generator for charged nanodroplets with sonic-jet ionizer was developed. The size distributions of ions and nanodroplets were measured as well as the electrical currents generated by ions and charged nanodroplets. The sonic-jet ionizer produced O-2(H2O)n ions with high density of 109-1010cm-3. When tetraethylorthosilicate (TEOS) and H2O vapors were added in the oxygen gas, the generator formed negatively charged nanodroplets with average diameter of 1.3-1.8 and 1.3nm, respectively. SiO2 nanoparticles synthesized from the charged TEOS nanodroplets were non-agglomerated. The size distributions measured at various furnace temperatures indicated that the formation mechanism of nanoparticles was ion-induced nucleation. In order to investigate the sterilization effects of negatively charged H2O nanodroplets, yeast fungi were exposed to the gas flow from the charged nanodroplet generator. Survival rates of yeast were clearly reduced by the discharge.

A new chemical vapor deposition (CVD) method, called ionization CVD, was developed, to produce non-agglomerated nanoparticles in which reactant gases are charged. A sonic-jet corona discharger was used as an ionizer in the developed nanoparticle generator. For a tetraethylorthosilicate (TEOS)/O2 chemical system, SiO2 nanoparticles were prepared. All particles formed by the ionization CVD were charged unipolarly. SEM micrographs of particles showed that the repulsive Coulombic force between charged particles reduces their coagulation rate and produces non-agglomerated nanoparticles that have a relatively high number concentration and small size. An external field was used to collect the charged particles onto Si wafers. These collected samples indicated that the deposition of charged particles could be controlled by the external electric field. Particle concentration measurement with a condensation nucleus counter at various TEOS concentrations suggested the particle formation mechanism in the ionization CVD was an ion-induced nucleation.

New Ru-based layered cuprates with 1232 structure have been synthesized in the RuSr2(LnCe2−x Sr x )Cu2O z (Ln = Sm, Eu, and Gd) system. Nearly single-phase samples are obtained in the composition range from x = 0.0 to 0.2 for Ln = Sm and Eu, and at the composition of x = 0.2 for Ln = Gd. Each of the samples of Ln = Sm, Eu, and Gd with x = 0.2 crystallizes in a tetragonal lattice and lattice parameters a and c are 0.3845 and 1.700 nm, 0.3842 and 1.699 nm, and then 0.3839 and 1.698 nm, respectively. Each of them shows some anomalies at a low temperature in addition to a semiconductor-like temperature dependence of the resistivity. Especially, the sample with Ln = Gd shows two resistivity dropping phenomena at about 16 and 22 K. Then, all of nearly single-phase samples show diamagnetic signals originating from superconductivity, and also rapid increase of magnetization due to a transition from paramagnetic state to ferromagnetic one below 80 K.

The effects of air pollution on asthmatic symptoms were assessed in a prospective cohort study of 3,049 schoolchildren in 8 different communities in Japan. Respiratory symptoms in these children were evaluated by questionnaires every year from the 1st through the 6th grades. The prevalence of asthma among the 1st graders was strongly associated with a history of allergic or respiratory diseases, but it was not associated with concentrations of air pollution. During the follow-up period, incidence rates of asthma were associated significantly with atmospheric concentrations of nitrogen dioxide. Particulate matter less than 10 μm in diameter (PM10) was also associated with a higher incidence of asthma, although the association was not significant. These findings suggest that air pollution, including nitrogen dioxide, may be an important factor in the development of asthma among children in urban districts.

Effects of NO 2 on particle formation in SO 2 /H 2 O/Air mixtures by f -ray irradiation as a source of hydroxyl radicals are investigated to evaluate the contribution of homogeneous and ion-induced nucleation in the nanometer-sized aerosol particle generation. The total particle number concentration, the charged-particle fraction, and the electrical mobility distribution of particles and hydrated and solvated ions generated in NO 2 /SO 2 /H 2 O/Air mixtures were measured at NO 2 levels of 0-1.98 ppm, SO 2 levels of 0-3.87 ppm, and H 2 O levels of 6480-9889 ppm. Total particle number concen2 tration first tends to increase with increasing NO 2 concentration up to a certain NO 2 level and then decreases for NO 2 concentrations beyond this point. The charged-particle fraction, indicative of particle formation by ion-induced nucleation, tends to decrease with increasing NO 2 concentration, reaching a minimum value. The peak intensity of the electrical mobility distribution for particles significantly exceeded...

Preparation of Bi2(LnxCa2−x)Ca2Cu3Oz thin films (0.3⩽x⩽0.7, Ln=Pr, Nd, Sm, Eu and Gd) by the laser ablation method and their physical properties are described. These films have been of a metastable Bi-2223 phase, which had not been synthesized by the solid-state reaction method. In the Bi2(PrxCa2−x)Ca2Cu3Oz system, the resistivity of Bi-2223 films has decreased with decreasing Pr content x, and the film with x=0.3 has shown the lowest resistivity. When x is fixed to 0.3 in the Bi2(LnxCa2−x)Ca2Cu3Oz systems, the film with Ln=Sm has shown the lowest resistivity. However, the result of the resistivity and magnetic measurements have shown that none of the films is superconductive.

Pulmonary responses to ozone exposure (1.0 ppm) were investigated in mice sensitized to ovalbumin compared with control mice receiving saline. Pulmonary function parameters were measured by pneumotachography. Arterial blood gases and the concentrations of soluble intercellular adhesion molecule-1 (sICAM-1) and tumor necrosis factor(TNF-) in bronchoalveolar lavage fluid were analyzed. Ozone exposure, when compared with filtered air exposure, caused significantly larger decreases in dynamic compliance (P 0.05) and minute ventilation (P 0.05) in ovalbumin-sensitized mice but not in control mice. Moreover, the decrease in minute ventilation in response to ozone exposure was significantly greater (P0.01) in ovalbumin-sensitized mice than in control mice. Ozone exposure caused a significant decrease in PaO2 in ovalbumin-sensitized mice but not in control mice. PaO2 after ozone exposure tended to be smaller in ovalbumin-sensitized mice than in control mice. The concentration of sICAM-1 in bronchoalveolar lavage fluid increased in ovalbumin-sensitized mice, but effects of ozone exposure were not observed. These results indicated that sensitization of the immune system to ovalbumin might be a risk factor which aggravates the effects of ozone exposure on the respiratory system. © 2002 Elsevier Science Ireland Ltd. All rights reserved.

We have already reported on substitution effects of Ba for Sr in the sulfur contained Pb-based 1212 compound with the composition of (Pb0.75S0.25)(Sr2−x Ba x ) (Y0.4Ca0.6)Cu2O z . It was found that each sample with x=0.3–0.6 showed a resistivity drop originating from superconductivity, and the highest onset temperature of the drop was about 32 K for a sample with x=0.5, but the volume fraction was very small. More recently, we have investigated effect of high-pressure O2 annealing on superconductivity of the Ba-substituted samples with x=0.4–0.6. As a result, the sample with x=0.5 is found to show an onset of the resistivity drop at the highest temperature of about 41.7 K and it shows an onset of the diamagnetic signal at about 42.0 K. These transition temperatures are higher by ∼10 K than those of the previously reported sample with x=0.5. Moreover, the superconducting volume fraction is increasing more by the high-pressure O2 annealing. These results indicate that the high-pressure O2 annealing effectively promotes superconductivity of the present (Pb0.75S0.25)(Sr2−x Ba x )(Y0.4Ca0.6)Cu2O z system.