In our previous study, results of the indoor performance test of a tilted-tray, wick-type solar still with a condensing chamber have been reported. In the present study, dependence of total distillate on saline water flow rate has been experimentally investigated. Performance tests were done and their results were compared with those of the non-circulation type solar still. It was found that the effect of the distillate on saline water flow rate was smaller at higher solar insolation than at lower insolation.
Separation of ionic or isotopic species in a magnetized sheet plasma has been studied by using the ion cyclotron resonance heating. The sheet plasma was used instead of a cylindrical plasma in which many unfavorable collisions take place. The rf electric field is applied to the plasma through two parallel electrodes. The resonance spectra of H+, D+, H2+, and He+ are clearly observed for the Ar or He plasma in which hydrogen or deuterium gas fed. It is found that the resonance peak shifts to the higher frequency than the calculated cyclotron frequency due to the plasma space potential of sheet plasma.
Cr doped poly-crystalline Al2O3 (sintered ruby) ceramics was fabricated with the vacuum sintering method using Al2O3 and CrO2 powders. The dispersion of Cr ion within Al2O3 matrix was characterized with EPMA. The optical properties of Cr ion were characterized using photoluminescence and absorption spectra. As the result, the possibility of sintered ruby for laser rod application was discussed.
The oxidation resistance of zirconium diboride (ZrB2) powder at high temperatures was investigated in order to determine the possibility of the use of additional material for improvement of the oxidation resistance in carbon-carbon (C/C) composites. ZrB2 powder with an average particle size of about 10μm was used in this experiment. The samples were oxidized at 300 to 1000°C for 5min to 25h in air. The weight changes were measured to estimate the oxidation resistance. The oxidation of samples oxidized for short oxidation time of 5min started at 700 to 800°C, and the weight gain increases with increasing oxidation temperature. On the other hand, at the oxidation time of above 0.5h, a maximum weight gain value at 700°C was observed. After that the weight gain decreased monotonically with increasing oxidation temperature. Based on the results of the X-ray diffraction analysis, monoclinic ZrO2 was present on the surface of the samples oxidized at 700°C and above. The peaks of tetragonal ZrO2, cubic ZrO2 and B2O3 could not be identified. The B2O3 of oxidation product vitreousd or vaporized at high temperature.
In this study, the oxidation of vanadium carbide (VC) powder at high temperatures was investigated in order to determine the possibility of its high-temperature use and additional material for improvement of the oxidation resistance of carbon-carbon (C/C) composites. VC powder with an average particle size of about 10μm was used in this experiment. The sample was oxidized at 300 to 1000°C for 5min to 25h in air. The weight changes were measured to estimate the oxidation resistance. The oxidation of sample for short oxidation times of 5min started at 300 to 400°C and weight gain change was measured with increasing oxidation temperature. The sample at the oxidation time of 0.5 to 1h, exhibited a weight gain change with increasing oxidation temperature. VC is oxidized to V2O5 at about 600°C.
The high temperature oxidation of tantalum carbide (TaC) powder was investigated in order to determine the application of refractory materials for space crafts and rocket vehicles. TaC powder with an average particle size of about 10μm was used in this experiment. The samples were oxidized at 573 to 1273K for 5min to 25h in air. The weight changes were measured to estimate the oxidation properties. The oxidation of samples, exposed for short oxidation times of 5min, started at 873K and weight changes increase with increasing oxidation temperature. The sample oxidized for 0.5 to 1h, exhibited increasing weight gain with increasing oxidation temperature, and constant weight gain above 973K. On the other hand, for oxidation times above 2h, the weight gain had a maximum value at 1073 to 1273K. After that it had a constant value of only 15%. Based on the results of the X-ray diffraction analysis, tantalum oxide (Ta2O5) was present on the surface of the samples oxidized at 973K.
Behavior of sulfur in high temperature oxidation of Fe-20Cr-4Al alloys with 491, 1300 and 6300ppm of sulfur was studied at 1473K for 18.0ks in 1 bar of oxygen. Mass changes of these alloys after the oxidation were almost the same of 0.60×10-2kg/m2. The oxide scales with good adhesion on each alloys were analysed as α-Al2O3 by XRD analyses. Observation of indentation by hardness measurement suggested that a highly ductile scales were formed on these alloys.
Silicon-Boron compounds were prepared by arc melting in Ar atmosphere from Si and B powders. The B content was changed from 50 to 90mol% (mole ratio of 1:1 to 1:8). From the result of the X-ray diffraction analysis, it was found that melted specimens were consisted of SiB4, SiB6, Si and B phases. The contents of free Si decreased with increasing amount of B. This means that, for the sample of Si-B with the mole ratio of 1:1 to 1:4, the peaks of free Si and B were recognized. For the sample of Si-B with the mole ratio of 1:5 to 1:8, the peaks of free Si, B, SiB4 and SiB6 were analyzed. The relative density of sample with the mole ratio of 1:5 and 1:6 were estimated as approximately 100%.
In this study, the oxidation of titanium carbide (TiC) powder at high temperatures was investigated in order to make clear the feasibility of its high-temperature utility. TiC powder with an average particle size of about 10μm was used in this experiment. The samples were oxidized at 300 to 1000°C for 5min to 25h in air; the weight changes were measured to estimate the oxidation resistance. The oxidation of sample at the short oxidation time of 5min, started at 400°C and weight changes increase with increasing oxidation temperature. The sample at the oxidation time of 0.5 to 1h, exhibited weight gain change with increasing oxidation temperature. TiC powder is oxidized to rutile-type and anatase-type TiO2 at about 400 to 500°C. Rutile-type TiO2 with transformation structure was found on the surface of the samples at high temperature (above 600°C). Anatase-type TiO2 and B2O3 could not be identified.
In order to improve adhesiveness of silicon rubber with acrylic resin, we tried to prepare a acrylic ester monomer containing Si-CH=CH2 group. It was found that the reaction of chloromethyl dimethyl vinyl silan (CMDMVS) with sodiumm methacrylate (NaMA) at 50°C in DMSO for 18h gave MMDMVS in 78% yield. Further, the copolymerization of methyl methacrylate (MMA) with MMDMVS in the presence of azobisisobutyronitrile at 80°C for 7h in THF gave corresponding copolymer in which contains Si-CH=CH2 group.
The diffusion reaction between 211 oxide substrate (e. g., 211 is the atomic ratio of RE: Ba: Cu; RE: Gd, Sm, Nd) and 035 oxide coating layer has been studied. Thick and uniform high-Tc superconducting 123 layer is synthesized for all RE systems. Moreover, in Sm and Nd systems the 224 layer is formed between the substrate and the 123 layer. The thickness of the 224 layer depends on the O2 partial pressure when reacted in the mixed gas of O2 and Ar. The formation of the 224 layer is suppressed by controlling the reaction temperature and the atmosphere. The Gd-123 layer formed by the diffusion reaction is composed of relatively large columnar and random grains. The transition temperature (1) of RE-123 phases depends on the O2 partial pressure of O2/Ar mixed gas atmosphere. Tc of the specimen reacted in open air is appreciably improved by the post annealing in O2. The highest offset Tc obtained in the present study for Gd, Sm and Nd systems are 94.0K, 92.3K and 91.4K, respectively, which are higher than that of the Y-123 phase.
In practical use of shape memory alloy, phase transformation temperature is very hard in control because the transformation temperature depends strongly on material composition, texture and residual stress. In this paper, we tested shot peeving treatment on the shape memory alloy for controlling the internal stress. We found the decreased transformation temperature after the shot peeving treatment.
Influence of tourmaline on sour taste of hot coffee was studied. The concentration of chlorogenic acid is a dominant factor for keeping the taste of coffee. The results of high performance liquid chromatograph (HPLC) indicated that the tourmaline prevented increasing concentration of chlorogenic acid Thus, the tourmaline is able to keep fresh coffee for a long time.
An enzyme electrode with NAD amplification for ammonia analysis was constructed by the combination of an oxygen electrode with an immobilized multi-enzyme (NADH oxidase, alcohol dehydrogenase, and NAD synthetase) membrane. The response time of the sensor was measured as one min. and the detection limit of ammonia was as low as 0.2μM.
Hippocampal LTP, well known as the learning model, is induced by tetanic stimulation to CA1 region in the hippocampus. The microelectrode techniques is advantageous in temporal resolution, while that of optical probing by functional dyes has advantage to spatial resolution. For long period observation from wider area, the recording by multi-array-electrode (MAE) is desirable. We applied MAE to the hippocampal slice to analyze the signal transudation property at the cellular level.
Relationship between sleep stage change and REM sleep was examined using polysomnography. EEG, EMG and EOG measured in normal and sleep deprived condition were analyzed. REM sleep was classified in two states with and without rapid eye movement (REM(+), REM(-) respectively). The quantity of REM(+) was decreased in sleep deprived condition. The role of the REM sleep in recovery sleep after sleep deprivation was discussed.
In order to analyze physiological feature during rhoenrad exercise, an Electrogastrography (EGG) was measured with healthy adult volunteers. Waveforms of EGG were analyzed using FFT. Three cycles per minuts (3cpm) component was odserved in EGG spectra in control condition. The component in rhoenrad condition was decreased and high freruency components (5-7cpm) were observed. Physiological nature of these components was discussed.
In this study an experiment was carried out to establish a convenient method of Pulse Transit Time(PTT) estimation. The time interval between ECG R-wave and PTG(τ EP) were measured under cooling stimulation and the induced autonomic response was analyzed. ECG R-Wave was used as a reference timing for PTT measurement. It was possible to use the time from EGG R-wave to PTG(τ EP) as an ergonomic measure.
In this study, local blood flow (LBF) was measured by using a near infrared light oxygenation (NIRO) monitor. Subjects were sitting on office chairs and a Sitzball (balloon shaped chair). LBF in Sitzball sitting condition was significantly greater than that in control condition. Physiological effects of Sitzball were discussed.
Effect of LiOH treatment for LaNi5 on the accelerated H2 absorption under the mixture gas of CO2 was demonstrated. Presence of CO2 in H2 usually disturbs the H2 sorption reaction of LaNi5, however, an increased reaction rate was observed for the sample with LiOH pretreatment. Increasing amount of CO2 in H2, however, decreased the reaction rate drastically. For the sample of LaNi2.5Co2.5 the effect of LiOH was not confirmed.
A concept of hydrogen system as an energy carrier in a new energy system was outlined. For the practical assessment on each new energy technology we applied the results of an environmental I/O model analysis which estimates the total amount of CO2 emission in the life cycle of the technology. As a typical example, we demonstrated a calculation for an energy system in averaged Japanese house including solar cells, batteris and/or conventional electric power connection.
We demonstrated the effect of an alkaline pretreatment on the H2 absorption characteristics of LaNi5. After significant oxidation breaks by air exposures in the course of sorption cycles, the sample with LiOH pretreatment reacted with H2 immediately. Analyses by scanning electron micrograph and Auger electron spectroscopy indicate the significant effect of Li in the surface oxide layer on H2 molecular dissociation.
In 1991, an unusual aluminum recycling dry process for beverage cans was developed, which enables that the more than 83 per cent of metallic aluminum can be retrieved from scrap cans within the quality of Japanese industry standard (JIS3004). However, in this process only the base paint powder is remained as waste after the pelletizing. We studied the characteristics of this base paint powder and investigated the possibility of utilization as a photo catalyst because of much contents of TiO2 in the powder.
The human being can recognize the three-dimensional world from the sight. The development of the display device adopted for a human sense is one of the goals of the image technology. This experiment try to complete of the device operating in time sharing mode.
We report the measurement of the negative-ion density in the sheet plasma by a photodetached method. We found that the generation of the negative-ion depends strongly on the electron density and electron temperature of the plasma.
The experiment of the antiparallel magnetic reconnection has been constructed to investigate the characteristics of the magnetic field in the neutral sheet plasma. The dependence of the magnetic field was measured by the magnetic probe. As the results, the direction of the magnetic field changes by the changing the argon gas flow ratio of the sheet plasma, that is, the electron temperature in the plasma.
To investigate the effect of an oblique the target on plasma paramerter, we measured the electron temperature, electron density and the electron current of particles at the end-target in a magnetized sheet plasma. These plasma parameters are unsymmetric at the upper and lower sides on the target.
The purpose of the study is the production of sheet plasma with high energy by means of the Ion cyclotoron heating. When the Ion cyclotoron frequency is applied to the rf electrode, the Ion temperature of the sheet plasma increases from 2.0 to 4.0eV.
This paper describes a method for obtaining a frequency stabilized laser diode with a Fabry-Perot resonator as a frequency standard, if which resonance frequency is slightly modulated, ie, wobbled. It was confirmed that AFC circuit functioned normally.
Our ultimate goal is establishment of an Optical Power System for industrial and commercial applications which consist of a highly efficient laser device and optical fiber transmission system. Output control of high power laser is an important problem. We succeeded in output power control using the Zeeman effect of the iodine atom.
The Chemical Oxygen lodine Laser (COIL) has unique characteristics and it is expected to be used in the energy field. Usually, Lasing threshold of COIL is decreased by the supersonic expansion. To obtain the high stagnation pressure at the plenum, helium is added as a buffer gas. However, using large amount of expensive helium is out of the question for industrial applications. We achieved a high efficiency operation of COIL using nitrogen as buffer gas. Obtained overall efficiency was 23.5% and it is the highest among the supersonic COILS using nitrogen gas a buffer gas.
Chemical oxygen iodine laser has various characteristics, which is considered to be effective as an illuminant of the optical power system. New type of SOG can be excited with high efficiency under the high pressure of singlet oxygen as well in the supersonic speed COIL SOG. In this paper we investigated dynamic character of Jet type SOG without buffer gas by using JSOG from the view points of miniaturization and low cost for the production.
We proposed a new unstable resonator, in which forward-mode and backward-mode coupled each other, for low gain large bore laser media such as COIL. The calculations showed that the new unstable resonator could be useful for COIL, which did not oscillate with the usual unstable resonators.
Spatial distributions of a small signal gain in a CO2 slab laser have been measured by two dimensional infrared camera. The small signal gain has its peak value in the center of the laser medium between two electrodes and decreases in the vicinity of electrodes because of ion sheath and wall de-excitation by diffusing upper level CO2 molecule.
The interaction between the high peak power femto-second laser and matter have revealed some interesting and new physical phenomena. We have begun to develop the high peak power laser system which will be used to form a plasma channel in the air for the study of the interaction between the laser beam and plasma. In this article, we discuss the pulse stretcher in the first step of the amplifier system.
This paper reports a quantitative evaluation by the various thin coating laser absorbents for laser hardening.Absorbents with a layer thickness of approximately 10μm based on such as graphite (Gr), boron nitride (BN) and silicon carbide (SiC) were coated on a SCM445 soft steel sheet. The results can be attributed to the difference in the heat conduction of thin coated materials.
A high speed photography technique was demonstrated in order to explore transient laser beam cutting phenomena. Dynamic cutting kerf production during a CO2 laser irradiation on soft steel and stainless steel sheets are imaged using a fix velocity cine moving picture camera. Such observation suggested that a detail analysis of the relations between laser induced plume contour and fusion zone should be required for the improved processing quality.
Anew type of the laser resonator has been studied for low gain and large aperture lasers. Numerical analyses clearly show the usefulness of the resonator. Experimental results are shown comparing to the analyses.
In order to construct STM, we made power supplies, amplifiers and programs for computer auto-measuring. We earned the data of tunneling current which increased as a tip moved horizontally on Au surface. From the data, we got the shape of gold surface by new method.
In this study, magnetostrictive thin films were prepared by do magnetron sputtering process. The magnetic and magunetostrictive properties were investigated in relation to the input power of 50-200W, Preparation of thin films exhibited perpendicular anisotropy.
The thermoelectric properties of the p-type SiC/Si sintered semiconductor have been studied as functions of Si concentration and temperature. The thermal conductivity decreases drastically with Si concentration compared with other dopants such as Al, Ag, Cu and Ni. The figure of merit Z approaches to 3×10-4 K-1 at around 750°C. We conclude that the addition of Si is most effective to reduce thermal conductivity for SiC based thermoelectric materials.
The ion-plating is used as a film formation process with a high deposition rate in many mass production processes. In this study, we investigated the formation of giant-magnetostrictive TbFe2 thin film by ion-plating process. The film composition of Tb-Fe film became Tb rich in comparison with source composition.
The reactivity of N2 gas molecules with Ti atoms (neutral and/or ion) in TiN film formation has been measured quantitatively. Increasing the fraction of Ti ions in all the evaporeted Ti from 2.7×10-3 to 0.26 enhances the N2 reaction probability up to 102 times and facilitates the formation of stoichiometric TiN.
In the railway engineering, the effect of a rolling wheel on the generation and propagation of micro cracks at the surface of a rail has been investigated for long period as one of the most important issues. On the other hand, recent development of high performance computers makes molecular dynamics one of the useful methods for investigating the materials properties at a scale of atoms and molecules. In this study, the molecular dynamics simulation is applied to the phenomena of micro crack generation and propagation at the rail surface during the long term rolling contact with wheels passing over them. EAM potential, which is regarded as very effective for metallic materials simulations, is employed as a potential function to introduce the mutual interaction among atoms in the molecular dynamics models. The resultant atomic behaviors in and around the cracks will be compared with the results obtained by the continuum mechanics analysis.
We studied on the change of physical state such as order-disorder transition at high temperature by considering its electronic characteristics. Consequently, Ti-49.5at%Al was transformed from order to disorder at 770K.
The influence of sintering temperature on vickers hardness of calcium hexaboride (CaB6)sintered body was investigated. CaB6 powder with of about 10μm in size was used in this experiment. The sample sintered at 1673 to 1923K for 3.6ks in vacuum by hot-pressing. The relative density of the sintered body increased with increasing sintering temperature. Relative density of the sample was 90% more than sintering temperature at 1873K. The relative density of sample sintered at 1923K showed 94%. The vickers hardness of the sample increased drastically with increasing relative density from about 4 to 8GPa for 90 to 94%.