We study by Monte Carlo simulation a model of fluid membranes whose Hamiltonian is a linear combination of Gaussian energy S_1 and a squared scalar curvature energy S_3. We find that the model has not only crumpled phases but also a branched polymer phase, and that the model undergoes a first order phase transition between the branched polymer phase and one of the crumpled phases. We find also that the model undergoes a second order phase transition inside the branched polymer phase.

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By using the molecular dynamics (MD) simulation, we study the second order phase transition of a model of crystalline membranes. We employ three kinds of techniques to solve the equation of motion : first two are based on the global coordinate system and the third one is based on local coordinate systems. The results are compatible with those obtained by Monte Carlo (MC) simulations.

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In order to dynamically clarify the friction mechanism between specimen surface and probe tip in the surface observation by atomic force microscope (AFM) or friction force microscope (FFM), several molecular dynamics simulations have been performed. In the simulation, a 3-dimensional simulation model is proposed where the specimen and the probe are assumed to consist of mono-crystalline copper and rigid diamond or carbon atom, respectively. The effect of cantilever stiffness of AFM/FFM is also taken into considered. The surface observation process on a well-defined Cu {100} is simulated. From the simulation results, it is verified that the surface images and the 2-dimensional atomic-scale stick-slip phenomenon just as observed through the real AFM/FFM surface observation can be detected from spring force acting on the cantilever. From the evaluation, it is clarified that the double slip and the dispersion in the stick-slip period occurs when the stiffness in the scan direction of the cantilever is low.

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This study aims to reduce the work-affected layer of the machined surface by carrying out the grinding at the speed over static propagation speed of plastic wave of ductile materials and also aims to clarify such super high-speed machining mechanism. This paper reports on the result obtained through the molecular dynamics simulations on the ultra high-speed grinding below and beyond static propagation speed of aluminum. From the simulation results, it is verified that the plastic deformation is reduced when the machining speed exceeds the material static propagation speed of plastic wave and its mechanism is completely different from that of the ordinary grinding process. The effective speed to the reduction of the plastic flow is also clarified.

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A finite element method was used to analyze the mechanism of stress development during thermal oxidation of shallow grooves on silicon substrates for 0.25-μm semiconductor devices. This analysis showed the resolved shear stress concentrates at the upper and lower corners of the groove. Moreover, the shear stress increases as the total amount of oxidation increases. In particular, the shear stress at the lower corner is about two times higher than that at the upper corner, and it strongly depends on the pattern width of the silicon substrate. These results mean that the amount of oxidation should be as low as possible and that the pattern width should be the most suitable for a SGI structure.

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We have developed a highly reliable memory module by modifying the dimensions of a tape carrier package (TCP). As the TCP is thin, it is a suitable structure for stacking. However, such thinness results lower flexural rigidity and shorter outer leads. Because of these features, the factors that control solder-joint reliability in the case of a TCP differ from those in the case of conventional package structures like a thin small outline package (TSOP). We evaluated the reliability of a solder-joint under temperature-cycling testing by using finite element methods. As a result, it was found that the distance from the chip edge to the solder edge on the substrate affects reliability considerably. It is thus concluded that increasing this distance, concentration of plastic strain can be reduced and solder-joint reliability can thus be improved.

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The coefficient of thermal linear expansion (CTE) of a superplastically elongated 3Y-TZP (3 mol.% yttria stabilized tetragonal zirconia polycrystal) was investigated. The experiments were conducted by using a push-rod dilatometer at a wide temperature range from 300K to 1473K. The experimental results indicated that CTE increased from 11.0×(10)^<-6>K^<-1> to 12.0×(10)^<-6>K^<-1> with increasing temperatures from 773K to 1200K and then showed temperature independence. Also, deformation-induced change in microstructures such as volume of cavitations fraction, the average grain size and grain aspect ration has little effect on CTE within to present experimental range.

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Hydroxyapatite (here in after referred to as HAp) is a bioactive ceramic having fine biocompatibility with bone of human body, because its chemical composition is similar to the human bone and the tooth. The HAp has an advantage that it can chemically adapt with the bone by comparison with the artificial bone that was made of other biomaterials. Generally speaking, bone has pores, but the pore may turn down the mechanical properties. In this study, HAp specimen having was discussed different porosity were subjected to the Izod impact test, bending test, Vickers hardness test, and observation on the fractured surface. It was confirmed that how effect of porosity on mechanical properties.

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Ceramics powder of 3Y-TZP, which can show superplasticity during and after its sintering process, was used as an insert material for solid-state bonding of a typical structural ceramic, Al_2O_3. The bonding temperature and stress were used as variables for the bonding experiments. The bonded states were observed by SEM and the bonding strengths were evaluated by four-point bending tests at room temperature. When the bonding stress was relatively low at each bonding temperature, insufficient flow as well as incomplete sintering of the insert material resulted, showing a very weak bonding strength, while when the bonding stress was quite high, the bonding strength was also relatively low. A maximum bonding strength was observed at a medium bonding stress. It was found that these results related closely with the amount of residual pores, which could partly relax residual thermal stresses, left in the insert material.

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A solid state bonding method between ceramics and metals using superplastic ceramics as interlayer-materials has been developed. Al_2O_3 was used as ceramics parts to be bonded, Ti-6Al-4V as metals parts, and 3Y-20A, 3Y-40A, 3Y60 as superplastic ceramic interlayer-materials. The superplastic flow that arises at temperatures of about half of the melting point and low applied stress in the superplastic ceramics was applied for the bonding process. The bonding experiments were carried out at different temperatures, bonding-stresses, bonding-times, thickness of the insert and various inserts, and appropriate bonding parameters were discussed. A joint-material having a good microstructure was obtained for Al_2O_3/Ti-6Al-4V at a bonding temperature of 1223-1273K and a bonding time of 15-30min.

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Small angle neutron scattering (SANS) method was applied to investigate morphology of cavities in superplastically deformed 3 mol% yttria stabilized tetragonal zirconia polycrystals (3Y-TZP). The 3Y-TZP specimens were deformed in tension at 1723 K with an initial strain rate of 3.3×(10)^<-4>s^<-1> in the air to pre-determined nominal strains ranging from 0.0 to 200%. Results obtained from SANS experiments were as follows : The volume fraction of all cavities showed no significant increase during the deformation up to nominal strain of about 20%, but it subsequently increased with raising nominal strain. Distributions of volume fraction of cavities to cavity diameter obtained from the SANS data showed that highest peaks appeared at a cavity diameter of around 0.4μm accounted for the largest in number among all the cavities existed.

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Generally, cavities are formed during superplastic deformations, and they subsequently grow with diffusion and/or plastic-flow or superplastic diffusion controlled mechanisms in metallic superplastic materials. Tensile test specimens of 3mol% yttria stabilized tetragonal zirconia polycrystals (3Y-TZP) were pulled at 1723 K with an initial strain rate of 3.3×(10)^<-4>s^<-1> in the air to nominal strains from 0.0 to 200%. Distributions of cavity number to cavity diameter were obtained by image processing on scanning electron micrographs. We proposed a simulation method to estimate cavity growth rates using data of the distributions. As a result, newly formed cavities grow very rapidly as soon as they nucleated, but their growth become slowly with increasing their size.

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Specimens of 3Y-20A (zirconia-alumina composite) were deformed superplastically to pre-determined tensile strains at various temperatures with different initial strain rates. Cavities were formed in the specimens during the deformations. The amount of the cavities in the specimens increased with an increase in the strain. Fracture toughness of the specimens changed complicatedly with the increase in the amount of cavities. It was found that the fracture toughness was greatly improved when the cavity volume fraction was around 1%. The fracture toughness was also affected by the cavity size. We concluded that the cavities with diameters of less than about 0.3μm can improve the fracture toughness, whereas the cavities with sizes larger than about 0.6μm have a negative effect on the fracture toughness.

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Applications of superplastic ceramics to nuclear energy fields are very promising because of their superior mechanical and thermal properties. In this study, Zr ion irradiation effects on superplastic deformation behavior of a typical superplastic ceramic, 3mol% yttria containing tetragonal zirconia polycrystals (3Y-TZP), were studied. Zr^<+11> ions with 130MeV were irradiated on the 3Y-TZP specimens by TANDEM accelerator at fluence levels of 3.5×(10)^<16> and 2.1×(10)^<17> ions/m^2. Their mechanical properties were examined by three-point bending test at elevated temperatures after the irradiation. As a result, at the temperature range from the room temperature to 1473K, any obvious irradiation effects were not found by the bending test. On the other hand, at the range from 1623K to 1773K, it was found that the superplastic deformation behavior was changed by the Zr ion irradiation. The activation energy of superplastic deformation was increased with increasing the irradiation fluence.

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Recently, it has become clear that some of structural ceramics show superplasticity, i.e., very high ductility. Applications of the superplastic phenomena found in the ceramics are very promising, because the structural ceramics, which usually possess more superior mechanical and thermal properties than metallic materials except for their brittle behavior, can be formed into complicated shapes by means of plastic working. The superplastic ceramics have potential ability for applications to atomic energy fields. Up to date, however, as far as we know, there have been few studies concerning the effects of irradiations on the properties of the superplastic ceramics. In this study, the effects of Zr ion irradiation on the mechanical properties of a typical superplastic ceramic 3mol% yttria containing tetragonal zirconia polycrystals (3Y-TZP) were examined and discussed. The effect of annealing on the variations of these properties were also investigated. It was found that the grain boundaries became relatively hence weak and deteriorated the mechanical properties of irradiated 3Y-TZP. The influence of Zr ion irradiation on the mechanical properties almost disappeared when the irradiated 3Y-TZP was subsequently annealed at 1173K.

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Solid Oxide Fuel Cells (SOFC) have exceptional potentials for electric power generation systems, because of their high energy conversion efficiency. Stabilized zirconia polycrystals are mainly used for the electrolyte of SOFC. Since superplasticity has been found in many kinds of zirconia-based polycrystals, its application to plastic forming of these polycrystals to make thin films or complex forms are very promising. Moreover, the application of superplasticity may connect with the improvement of electrolyte characteristics. In this study, superplastic properties, mechanical properties and electrical properties of typical zirconia polycrystals for the electrolytes, i. e., 3 to 10mol% Y_2O_3-doped zirconia polycrystals and 4 to 10mol% Sc_2O_3-doped zirconia polycrystals were examined, and the superplastic properties of the electrolytes were discussed.

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Fe_<0.9>Mn_<0.1> _<75>C_<25> balk specimens were produced by Mechanical Alloying and Spark Plasma Sintering. Compression tests were conducted at 973K, then change in grain aspect ratio during the compression tests were examined. Consequently, the plastic strain at 973K is given mainly by grain boundary sliding. This result suggest the occurrence of superplastic deformation. It was confirmed by laser beam microscopy and strain rate exponent.

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With increasing population of aged people in the society, demands for artificially produced part of human body are growing rapidly. Now titanium alloys have been highlighted because of their excellent corrosion resistance. In this study, high temperature deformation for a newly developed beta titanium alloy, Ti-29Nb-13Ta-5Zr, has been studied in comparison with that for a Ti-15V-3Cr-3Sn-3Al alloy, one of the most popular beta alloys, and the possibility of superplastic forming has been searched for. Strings that appear along flow direction in microstructure of the Ti-29Nb-13Ta-5Zr alloy have been investigated in terms of local composition by means of energy dispersive X-ray microanalysis.

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In this research, as an easy grain refinement method, wrought products of a commercial magnesium alloy AZ31 have been subjected to further cold rolling and subsequent annealing. In the previous report, this method was found to reduce the grain size by more than 15% and to improve tensile properties at room temperature. In this study, high temperature tensile tests were performed on hot-rolled sheets with and without this grain-refining treatment. As a result, higher ductility was not obtained for the grain-refined materials in a low-strain-rate region at 300 and 350℃. This was consistent to the optical microstructural observation showing that the grain grew more rapidly in the grain-refined material during the deformation than in the hot-rolled sheet without grain-refining treatment. This rapid grain growth was attributable to a wider grain-size distribution in the grain-refined materials.

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An Al-Zn eutectoid alloy known as a fine-grained superplastic material is tested in tension and compression under superplastic condition, and the influence of the stress state on superplastic deformation behavior, such as flow stress, is investigated. In the compression test, deformation is interrupted and turning is performed to remove a barreled portion so that the specimen section becomes uniform, and then the deformation is continued. As the result, flow stress in the compression becomes higher than that in tension although it is found to be slightly reduced by the removal of barreled portion.

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In this study, the high strain-rate superplastic deformation was carried out for a Zn-Al alloy by tensile tests at room temperature and high temperatures. Before and after the tests, the dynamic hardness and the thermal conductivity were evaluated, and the temperature increasing rate and the m value due to high strain-rate superplastic deformation were also evaluated. The temperature increasing rate in the case of low strain-rate superplastic deformation at high temperature was lower and the m value in the case of the test condition was higher. The dynamic hardness in the case of low strain-rate superplastic deformation at high temperature was lower and the thermal conductivity in the case of high strain-rate superplastic deformation at high temperature was higher.

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The influence of the T7 heat treatment exerted on AC4CH metal matrix composite (MMC) reinforced with 20vol.% SiCParticle was considered from various angles. The obtained results is as follow. (1) As for MMC, the improvement in on the strength with as fast fatigue strength as the improvement in about 60% was found by T7 heat treatment. This showed that T7 heat treatment of MMC did big improvement to the fatigue characteristic. (2) There was no big variation in the S-N diagram of both of material, and inclination was almost the same. This can be considered to be the result of toughness value maintenance having been useful with the fault prescription processing which is the characteristic of T7 heat treatment (3) The measurement result of SEM was arranged using the extremum probability method. Consequently, the crack of a SiC particle suited the downward tendency of T7 material rather than F material. As for this, the T7 material is considered because high compression remains stress occurred also 1.4 times to a SiC particle rather than F material.

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The effect of the strain by using ADC12,it carried out the fatigue crack progress test, and conducting the plastic workig on the fatigue crack progress characteristics was clarified. The result obtain are as follow. (1) Crack growth distortionlessness material strain material there low-speed a large. that is to say, the crack growth of the prestrain material advances early the inside of possible plastic zone by giving the strain. (2) It is necessary to notice for guaranteeing the safety in not only. K_<th> but also size of the plastic zone.

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In order to make low the friction coefficient between the flange parts of railway wheel and which ride and cause uphill derailment, it considered diving a DLC leather filmHowever, this DLC leather film is not used in the place of high load and high-speed rotation. Then, the destructive mechanism of a leather film was solved in this experiment, and it aimed at tying to creation of a future leather film. And although a friction coefficient can reduce a DLC leather film by having composted as an obtained result, the durability of a leather film is missing. Therefore, a leather film needs to be improved.

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Though the platinum is one of the representative precious metals, the platinum has been used as an industrial use material of the crucible for the glass melt recently. In this study, the fatigue reliability at elevated temperature of platinum alloy which was the industrial use material demonstratively was examined by the elucidation of fracture mechanism. Main results were follows; (1) S-N characteristics of the PtRh alloy was almost arranged in the straight line. And, the (10)^7-fatigue strength was 30MPa. (2) From the fractography using SEM, it was indicated that fatigue fracture mechanism was similar to the static destruction in the high stress side, on the other hand, it was effected by creep in the low stress side.

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Aluminum alloy sheets are attracting attention since they lighten an automobile body. Among them, some Al-Mg-Si alloys have already been applied to a part of automobile bodies because these alloys have hardenability during paint baking and do not cause a stretcher strain pattern. However, their bendability is significantly poor compared to that of steels. Therefore, in this paper, close microstructural observation has been made on the side surface as well as tension surface, in order to clarify the influence of the difference in the alloy composition, i.e., amount of Mg_2Si, amount of excess Si, Cu addition, etc. Special care has been taken to the occurrence of the crack and unevenness. As a result, cracks were found to be prone to form when the amount of Mg_2Si or excess Si increased, although the increase in the amount of alloying element, particularly Cu, caused grain refinement.

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Recently, extensive effort have been made to replace aluminum by copper for the interconnect materials in the Si-ULSI devices. On the other hand, application of a lower specific inductive capacity, Low-k, material to the intermediate insulation film between copper and silicon is also a serious subject. The purpose of the present study is to assess the stress change accompanied by heating and cooling on copper films deposited on a silicon substrate with three insulation layers having different capacity, and to clarify the influence of the insulation film material on the thermal stress. The assessment was carried out by measuring the curvature of the samples during heating and cooling. As a result, tensile stress at room temperature both before and after the heat cycle was reduced, and maximum compression stress at elevated temperatures was raised, when the capacity of the insulation layer was lowered.

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A purpose of this study is the development of high performance bio-ceramic composite materials, which have excellent mechanical properties and high fracture toughness as several times of characteristics of the human bone. For the purpose, the hydroxyapatite (HAp), which had excellent bio-compatibility and biotic activity, was reinforced by carbon fibers (CF) having bio-adaptability. The microstructures and the mechanical properties were evaluated. The compressive strength of the bio-ceramic composite material manufactured by carbon fiber oxidized for 15 hours (CF-15/HAp) was excellent about 3 times of the of the bone, the Young's modulus was nearly equal to that of the bone and the microstructure showed the strong bonding between HAp and CF. Therefore, this CF-15/HAp composite material was considered to be effective on the utilization as a high performance biomaterial.

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High-energy planetary milling has been applied to prepare precursors for the two kinds of cathode materials, LiNiO_2 and LiMn_2O_4,for rechargeable Lithium-ion batteries. The LiNiO_2 precursors can be converted to well-crystallized powders at 700-750℃ where the vaporization of lithium species is limited. Fine grinding and mechanical activation of the starting materials, enhanced mixing, and the encapsulation of the staring materials into sub-micrometer agglomerates, enables the synthesis at the low temperatures without feeding and excess O_2 gas. The resultant LiNiO_2 provided and excellent rechargeability up to 140mAhg^<-1>. The peculiarities of this method can be efficiently applied to the synthesis of LiNiO_2. Fine and uniform particle size in addition to the crystallinity required for this material is attained by heating the precursors above 500℃. The particle size of the synthesized powders are 72nm at 500℃ and 127nm at 700℃.

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The effects of finer particle size of starting powders, addition of pinning particles, and precipitation strengthening using celsian have been examined to limit the exaggerated growth of mica grains in machineable glass-matrix composites. Grinding the starting powder reduced the large interlocked structure and contributed to the improvement of sinterability and the reduction of grain size and related size of residual pores. The doped TiO_2 acted as the pinning sites to improve sinterability and strength. The doped YTZ was effective pinning sites. The obtained fine grained material showed improved strength, hardness and fracture toughness. Celsians once dissolved into the glass to promote densification below 1080℃ and improved the mechanical properties. Annealing the materials at 1120℃ enabled the precipitation of fine celsian particles.

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Tri-layer composites consisting of surface layers with residual compressive stress and a stress-tolerant inner layer have been fabricated by the oxidation of alumina-matrix composites dispersing intermetallic NiAl. The residual surface stress is generated by the volume expansion due to the formation of NiAl_2O_4. The starting Al_2O_3-NiAl powder was prepared by heating the precursor mixture of α-Al_2O_3 powder for the matrix and (Ni, Al)-hydradino-benzoate precipitate of at 1200℃ in Ar. The fracture toughness of. the 10vol%NiAl-Al_2O_3 composites was 6.3MPa・m^<1/2>, indicating the suitability as the inner layer material applied under tensile stress. The measured surface compressive stress for the tri-layer composites was more than 120MPa and this stress improved the fracture toughness to 1.5 times of the dispersion composites at the degree of oxidation of 85%. However, when the surface oxidation progressed to more than 90%, much defects formed at the boundary of the surface and inner layers to relax the stress and degrade the toughness.

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The conventional way of fabrication greentape used in the GTLS method is by mixing metal fine powder with organic binder and solvent into slurry. The tape is formed from the slurry by the doctor blade method into the thickness of 100-200μm. The substances contained in organic binder such as PVB, DOF, toluene and methyl-ethyl-ketone are suspected as one of the endocrine disrupting chemicals. In addition, the bad influence on the sintering result by the gas released from the binder during laser sintering process has also been discovered. Therefore, the present research is to develop a new greentape with environmental friendly binder that can be replaced by the organic binder. This new greentape using ager is capable of producing sintering parts with higher density and strength compared to the conventional greentape.

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There is an increasing demand of superior artificial bone in Japanese medical industry due to the aging society. The objectives of the current research are to fabricate artificial bone by the GreenTape Laser Sintering (GTLS) method and to evaluate the strength of the sintered part by bending test. GTLS has the advantage of producing the required shape of artificial bone in a short time. Besides that, the liquid phase sintering in GTLS is capable of producing a porous part similar to the actual bone, so that the density of sintered part can be kept at a low value. Atomized powder of titanium (82.95 μm in average particle size) is used as the material for the artificial bone fabrication in the present study because of its superior mechanical characteristics and good biocompatibility with the human body.

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Microstructure evolution in the HAZ of laser welded ultra-fine steels were investigated using a 20 kW CO_2 laser facility. A narrow softening region was clearly observed in the HAZ welded at low welding speeds of less than 0.017 m/s. Softening was caused by coarsening of ferrite grains. On the other hand, HAZ softening was suppressed at higher welding speeds of more than 0.033 m/s due to formation of tiny dispersed MA constituents and reducing grain coarsening.

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DLC (Diamond-like carbon) films were deposited by a plasma CVD method using various hydorocarbons. The friction and wear test was carried out changing sliding speed, normal load and relative humidity. The wear track and debris were observed by optical microscope and SEM. The friction coefficient of DLC films had a tendency to increase in high humidity and the specific wear rate of DLC films decreased in high humidity. The fold pattern was observed on the friction surface of DLC film especially in high humidity test. The features of debris on DLC films varied by changing humidity. The friction and wear properties of DLC films deposited by various hydrocarbons had no obvious difference.

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Research on the comfortable click characteristic is done about a Metal Diaphragm, using CAE effectively. The effect of residual stress for manufacturing process is influences of comfortable. The synthetic design by Virtual Manufacturing which went back to the forming process and put the influence of remains stress into the view is performed in that case. A result of this study, considered influence goes back to the forming process of a Metal Diaphragm, and affect the comfortable click characteristic as effective use of CAE.

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In the future, the aging society will come in Japan. So it will be almost impossible to nurse to old people. Recently, the welfare equipment has been developed to support of independence life and barrier free. However, they have not been designed with the sensitivity. Therefore, we will sense the discomfort when we use the welfare equipment. In this study, we tried to develop the buggy cane suitable for the operation of human. Concretely, study contents are as follow; (1) Outline design of the buggy on the basis of result of the questionnaire (2) Design of the buggy cane that applied theory of TRIZ (3) Examination of wheel's structure that applied smart lubrication function suitable for the operation of human. From these results, we tried to develop the "wonderful" and "comfortable" buggy cane.

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In the future, the aging society will come in Japan. And, old people will increase very much. So It will be almost impossible to nurse to old people. Then the field study was carried out, and the development of hand phone with user's opinions was tried in this study. The field study result is digitized. And the human sensitivity is quantified. And research on the comfortable click characteristic is done about a Metal Diaphragm, using CAE effectively. A result of this study, considered influence goes back to the forming process of Metal Diaphragm, and affect the comfortable click characteristic as effective use of CAE. The Snap bucking pushes it, and large effect is given for the feeling.

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Effect of elevated temperature on fatigue reliability of halogen-free printed circuit board was evaluated. Especially fatigue mechanism at elevated temperature was demonstratively carried out. Main results were as follows. (1) Fatigue life of halogen-free material at elevated temperature were shorter than that at room temperature. (2) From fractography by using SEM(Scanning electron micrograph), resin adhesion to reinforced fiber at elevated temperature was less than that at room temperature. From this fact, it was suggested that fatigue crack propagation of halogen-free material at elevated temperature occurred in interface between reinforced fiber and resin, and that at room temperature occurred during resin. It was thought that difference of fatigue mechanism effected fatigue life.

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Platinum is one of the typical precious metals, and, probably, has an image as an object for accessories. However, it is used for the field broad as an object for industry In this study, in three kinds of Pt alloy (Pure Pt, PtRh10%, T-1Pt), it examines for the purpose of the elucidation of the fatigue destructive mechanism in Pt alloy for industry, each destructive form is compared, and examined. Main results were follows; (1) fatigue strength of PtRh10% is 110MPa, of T-1Pt is 60MPa As opposed to the fatigue strength of pure Pt is 40MPa (2) Destructive forms were static ductility destruction in three kinds of Pt alloys. (3) The intergranular crack occurred only in PTRH10. It was what is depended on the difference in the strengthening method.

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The purpose of this study is that improvement of lubrecating properties in the human lifespeed area by using porous film that is hard and have many holes on the film and mixed grease.results are as follows. (1) Conparing uncoated and porous in the torque tests, differenses weren't gain in torque property in each grease. (2) The hybrid film was created by inpregnation of micro-porous of porous film with MoS_2 on each grease. This is very affective against redusing torque in very-slow-speed-range. (3) By analysing grease flow on spinel film, thin grease film was created on the porous film. By this, increasing torque by rough surfase on spinel film could prevent. (4) Examining containing rate of MoS_2 in porous film, increasing containing rate of MoS_2 brings about redusing torque in very-slow-speed-range on each grease. Inpregnationing is more affective in softner grease. (5) Depending on the hyblid film, redusing torque and improvement of lubrecating properties in the human lifespeed area were obtained relative to compositing spinel film and mixed grease.

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Axial type magnetically suspended motor, which does not have bearings of a motor shaft, has been developed. The developed motor consists of a top stator, a levitated rotor, and a bottom stator. The top stator has four permanent magnets to produce upward directional bias magnetic force to the rotor. The top stator also has two pairs of electoromagnets to control the radial position of the levitated rotor. The bottom stator has two sets of coils. A set of the coils produces the attractive force to control the axial position of the levitated rotor and produces the rotating torque of the levitated rotor. The other coils is used to control the inclination of the levitated rotor. A magnetically suspended centrifugal pump was constructed with the developed motor. A closed-loop circuit filled with the water was connected to this pump to examine performance of the pump and the magnetic suspension system. Maximum rotational speed, flow rate and pump head were 1100rpm, 4.3l/min and 48.6mmHg, respectively. The developed pump indicated the potential to be an artificial heart with further improvement.

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This paper proposes a new type of self-bearing motor which uses Lorentz force. It is expected to have good dynamic response, and high levitation capability. For realizing high magnetic flux, Halbach magnetic circuit is designed and used for the rotor. First, the fundamental principle is introduced how the motor produces linear rotating torque and radial levitation force. Next, Halbach magnet is introduced and its flux distribution is analyzed using FEM. Finally the negative stiffness and the control force is calculated to confirm the stable levitation.

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A centrifugal blood pump with a double pivot impeller and an eccentric inlet port is under development for implantable artificial heart by Baylor college of medicine/Miwatec Co. Ltd. To eliminate fluid dynamic causes for thrombus formation, flow visualization analysis was conducted to evaluate the flow patterns and the shear rate distributions. It was found that an eccentric vortex is formed in the pump apart from the pivot center as the prerotation caused by the eccentric inlet port. Since a similar eccentric vortex is also formed behind the impeller, the pivot is exposed to sinusoidally changing shear rate. The minimum value was found to be 650(sec)_<-1>. It was found that the value can be increased to more than 150% when the male pivot is lifted from the female pivot by 0.6mm.

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To improve the durability of centrifugal blood pumps, rotational wear tests and creep tests for pivot bearings were conducted. The pivot was assumed to be composed of a male pivot made of semi-sphere ceramic and a female pivot made of ultra high molecular weight polyethylene (UHMWPE). Regarding the female pivot, three kinds of UHMWPE were compared for two molecular weights and with/without gamma lay processing. The experimental results showed that the durability of gamma lay processed UHMWPE was the best against wear and that the creep characteristics were commonly recognized.

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Completely implantable electro-mechanical ventricular assist device (VAD) has been developed. This device is intended for the patients of 50-60kg weight. The blood pump housing is made of titanium alloy (Ti-6Al-7Nb) and flexing blood-contacting diaphragm is made of segmented polyurethane with MPC coating. In vitro and In vivo tests showed good performance as a left ventricular support device. For the further improvement of endurances, impact strength of the mechanical in the mock loop simulating the systemic circulatory condition resulted in possibilities of deterioration of endurance performance under the specific control condition. For the further improvements in higher endurance and higher efficiency, precise evaluation of optimal control patter of motor speed that will not prevent the pump for full fill condition is needed.

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In this paper, linear oscillatory actuator (LOA) for the ventricular assist device (VAD) has been developed that provides reciprocating motion without using any converter mechanism. The LOA consists of a piece of stator with single-winding excitation coil and a piece of mover with two permanent magnets. The simple structure of LOA is based on fewer parts to bring about high reliability and smaller size. The principal feature of our LOA is the non-symmetry thrust characteristics that results from the unique structure of the stator-yoke. To drive VAD in a systole phase, a large force is necessary to the actuator. However, a small force is sufficient to drive VAD in a diastole phase. We developed the non-symmetry LOA which generates high thrust in a systole phase alone. A magnetic field analysis was applied to design our LOA. The dimension of the LOA to be developed is 60mm diameter and 24mm thickness with 68ml volumes and 465kg weights. In the systole phase at input power of 20 watts, the maximum static thrust was approximately 195N. In the diastole phase at same input 20 watts, the maximum static thrust was approximately 73N. The static thrust of systole phase was about 3 times larger than diastole with same input electric power.

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The objective of this study is to develop a man-machine interface for collecting visual information for tele-surgery. Developed system consists of a master part and a slave part. The master part has a gyro-sensor system to detect movement of the head and a face-mounted-display to present visual information to users. The slave part consists of a slave robot mounted on a CCD camera to collect images. The slave robot is driven by four wires mechanism, which is emulated human jugular muscles construction, based on the signal from the master part. Basic control performance of the slave robot was examined. Maximum controllable angles of the robot were 15 degrees around the x and y axes and 7 degrees around the z axis, respectively. The slave robot could be controlled based on the head movement detected by the master part. But, the rotation around z axis has 7 degrees difference with the real head movement. Further improvement of the wire mechanism of the slave robot is needed.

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This paper proposes an Electromagnetic Valve Actuator which has permanent magnet and electromagnet. The permanent magnet is located between the stator core and the armature to provide bias flux and to hold the armature on the surface of poles. The armature is driven by two springs and electromagnets. This actuator can reduce the driving power than solenoid type actuator. Because the solenoid type requires current to hold the armature. This paper describes the experimental results of this actuator. Furthermore an improvement method is proposed for small size and high performance.

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A mercury target installed in a neutron scattering facility is heated instantly by the hitting of 1MW pulsed proton beam. Then, a pressure wave will be generated in mercury, and a target container made of SUS316L could be loaded excessive dynamic stress caused by the pressure wave. The liquid-structure interaction analysis with LS-DYNA code was carried out to make clear behaviors of the dynamic stress, and also to estimate the possibility of the mercury cavitation under the pressure wave propagation. Analytical results showed that the maximum amplitude of the dynamic stress was about 154MPa, which was less than the allowable stress, negative pressure was generated near the beam window, which would cause the cavitation in mercury.

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