This paper utilizes power estimation equation for the microprocessor which was introduced in former work by the author and describes transient heat conduction simulation for the lidless micro PGA (Pin Grid Array) processor. Not only temperature and voltage dependency of microprocessor power consumption but also cooling performance expression is critical for transient heat conduction simulation. Therefore, this paper tries to focus the expression of cooling performance by heatsink fan including the case of changing fan speed.

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In order to decrease the thermal displacement drift of the precision positioning device, so far, many cooling methods have been suggested and some of them have been already applied to the actual positioning system. In this report, the normal-type positioning device in which ball screw was indirectly connected with the motor shaft by a coupling, together with the moving stage and the support unit of ball bearing were cooled by three Peltier modules. As a result of a serial experiment, it is found that with the introduction of the Peltier modules, the heated positioning system could be cooled back to the room temperature and the thermal displacement drift was effectively decreased. Besides, the temperature distribution inside the ball screw and the bearing was numerically calculated.

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This paper evaluates single-phase heat transfer performance of copper minichannel fins and describes applicability of this device to the future electronic power devices. The minichannel fins achieves quite high heat transfer performance of approximately 90,000W/m^2K at 300W/cm^2, which proves that the single-phase heat transfer of the minichannel fins enables to cool down the future power devices.

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Two sizes of plate-type heat pipes were produced experimentally by diffusion bonding of two copper thin plates. Thermal performances of these plate-type heat pipes were examined by liquid cooling of condensation section. For large-scaled plate-type heat pipe which 3.8mm in thickness, 40mm in width, and 375mm in length, thermal resistance of 0.06K/W at maximum heat transport ratio of 250W was obtained in the bottom heat condition. Verification tests of cooling for CPU in server with these plate-type heat pipes were also carried out using real server, and CPU case temperatures were kept lower than 60℃ for both heat pipes.

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Efficient optimal control scheme for transient temperature profile in micro devices has been developed based on the adjoint equation of one-dimensional heat conduction in solid layers. Surface heat flux applied with a thin-film heater is employed as the control input in order to minimize temperature changes of a thin active layer embedded in a modeled laser diode. The present feed-forward control scheme provides the optimal heat input, of which magnitude is predominant prior to the onset of a laser pulse. Both in numerical simulations and MEMS-based experiments, the temperature variation during the laser emission can be successfully suppressed by more than 60 % with the present control.

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The aim of the present study is to clarify the flow characteristics of the narrow gap between the inner rotating cylinder and the stationary coaxial cylinder which simulates the geometry of the rotor and the stator of an electric vehicle (EV) motor. In the present study, the flow of the rotor cylinder surface and the region of the rotor end part which is the space between rotor edge face and stator edge face are visualized with Kalliroscope flakes. As a result, it is suggested that the flow of the stator edge face influenced the flow on the rotor cylinder surface with Re applied the experimental parameter increasing.

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To design motor of an Electric Vehicle (EV), one must take care on heat transfer system due to that high current density on the component compared with other industrial motor is applied. Excessively heat generation may cause irreversible fail effect such as demagnetization and burnout of mounted coils. We attempted to simulate flow inside model of an EV motor according to the way that field of the flow can be separated into narrow "gap" and "rotor end part" focusing to pressure on boundary of the system. Pressure field of flow shows that possibility to control heat transfer between both regions because of sensitively with boundary wall on which vortex seemed like Taylor-Couette flow is generated.

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This paper describes the results obtained by the numerical simulation for H_2-air premixed gas combustion considering surface reaction on wall in a narrow parallel plate channel. In our previous study, the high heat release region near low temperature wall, where the reactions do not seem to occur at first glance, is observed. In this study, the reactions in the high heat release region near wall are investigated, and the influence of the surface reaction on the high heat release region on low temperature wall is elucidated.

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The effect of burner angle on microflame in natural convection field has been investigated in terms of combustion intensity and efficiency based on measurement of the power of CH* emission. When the burner is vertical downward (upward), the maximum combustion intensity is obtained at the flame tip (at the part where flame width is a maximum). The total power of CH* emission of vertically downward flame is remarkably increased compared with that of vertically upward flame. It suggests the increase of the combustion efficiency of vertically downward flames.

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Combustion characteristics of H_2/O_2/N_2 mixture were investigated by using a micro flow reactor with a controlled temperature profile. Two flame responses were observed experimentally by changing the inlet mixture flow velocity. By gas sampling analysis, it was found that reactants were completely consumed in the low flow velocity region in which no flames were visually observed. 2-D computation with detailed chemical mechanisms of gas phase reaction and surface reaction was conducted to examine the effect of radical quenching on the wall surface. By comparing the computation to gas sampling analysis, it was supposed that the surface reaction mechanism may overestimate the effect of radical quenching on the wall surface.

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The cellular structure of methane-air lean premixed flames on a flat burner was studied by the planar laser-induced fluorescence (PLIF) of CH radicals and by the time series analysis on light emission for reconstructed attractors. We treated two types of mixtures, i.e. CH_4/Air (Type-1) and CH_4/O_2/CO_2 (Type-2) mixtures. As the equivalence ratio became lower, the cell size and depth increased, which was due to diffusive-thermal instability. In addition, the cell size and depth in Type-2 mixtures were large compared with Type-1 mixtures. To study the characteristics of the unstable behavior of premixed flames, we obtained the reconstructed attractors. The attractors had a doughnut shape, which indicated that the behavior was quasi-periodic. As the equivalence ratio became lower, the attractor became larger and the trajectory became more unstable.

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Counterflow of methane-air premixed gas and burned gas with active radicals are calculated with detailed kinetics. It was found that the effects of addition of radicals on extinction limits and flame structure are not significant. There are small difference between addition and no addition of radicals. Furthermore, due to the strong radial-direction flow, added radicals are transported to radial direction by convection and diminished. Meanwhile, temperature of countering burned gas has a dominant effect on sustaining premixed flames. High-temperature burned gas affects weak flame and its extinction limits are extended. These results agree well with the results of counterflow flames of propane-air premixed gas and burned gas conducted by Darabiha et al. [Darabiha, N., et al., Combust. Sci. Tech., 60 (1988), 267.].

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Dominant parameters in unsteady flame structure of hydrogen/air counterflow premixed flame are investigated by numerical simulation with elementary reaction model. In order to investigate unsteady flame, a sinusoidal fluctuation is added to the inlet velocity of hydrogen/air premixed mixture. The conditions of various fluctuation frequencies and average velocities of the inlet velocity are considered. As candidates of dominant parameters, the reaction progress variables defined with mass fraction of hydrogen evaluated at flame front are proposed. It is found that the maximum heat release rate and the maximum mass production rate of various species are determined by the reaction progress variables.

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In this study, we have applied a large eddy simulation (LES) with 2-scalar flamelet approach to a prediction of lean premixed combustion and NO production in a lean premixed combustor of 18MW class gas-turbine, L20A-DLE by Kawasaki Heavy Industries, Ltd. Validation of our result is performed by comparing with experimental data. The results show the possibility of LES with 2-scalar flamelet approach as one of the efficient analysis methods to predict phenomena in lean premixed combustion of combustor.

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In order to clarify and establish a model of the turbulent burning velocity of multi-component fuel mixtures, the turbulent burning velocity of hydrogen added methane-air mixtures with a wide range of equivalence ratio and hydrogen additional rate was examined. The turbulent burning velocity S_T at the same u'/S_<L0> was found to tend to increase with adding hydrogen to methane-air mixtures. The increase of S_T with hydrogen additions in lean mixtures was larger than that in rich mixtures. Additionally, a model of turbulent burning velocity proposed for single-component fuel mixtures may be applied to two-component fuel-air mixtures by considering the estimated mean local burning velocity.

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Direct numerical simulation (DNS) of a hydrogen-air turbulent premixed flame propagating in homogeneous isotropic turbulence was conducted to investigate the local flame structure and fractal characteristics in high Reynolds number turbulence. A detail kinetic mechanism including 12 reactive species and 27 elementary reactions was used to represent the hydrogen-air reaction. In high Reynolds number turbulence, very complicated flame structures induced by strong coherent fine scale eddy were generated and strong correlation between the inner cutoff and the ratio of diameter of coherent fine scale eddy to laminar flame thickness was observed.

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Burning velocities and configuration of turbulent propagating flames were investigated for iso-octane/air mixtures at equivalence ratios of 0.8, 1.0 and 1.4. The laser tomography was adopted to obtain the cross-sectional images of turbulent flames. The flame front area was evaluated using the perimeter of the cross-sectional image of turbulent flame. The flame brush thickness was also examined. The normalized perimeter of the cross-sectional turbulent flame image was found not to vary so much with equivalence ratio at a constant turbulence intensity, although the ratio of turbulent burning velocity to unstretched laminar burning velocity increased with equivalence ratio. On the other hand, flame brush thickness seemed to vary slightly with equivalence ratio.

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We examine the influence of droplet size and number density on flame propagation characteristic in fuel spray by numerical simulation. We ignite forcedly in fuel spray region in which a lot of fuel droplets are dispersed randomly. Especially, we elucidate the dominant parameter for flame propagation velocity.

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This paper reports the initial results of droplet vaporization behavior suspended by optical tweezers. The main concept of this study is to observe noncontact droplet in order to eliminate the fiber effects and the vaporization of water droplets were successfully observed. The maximum diameter of suspended droplet is around 16 μm and the vaporization rate constant are the order of 10^<-5>mm^2/s. The effects on the vaporization of surface tension and convection around the droplet are discussed. As a result, the vapor concentration of ambient dominantly affects vaporization behavior and the improvement of ambient condition control was suggested.

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In this research, secondary atomization of emulsififed fuel spray was investigated. An emulsified fuel spray was injected into the high temperature inert gas, and its secondary atomization behavior was observed by a high-speed video camera with shadow imaging method. As a result, spray droplets with a diameter of around 50 μm were clearly visualized. Puffing behavior of spray droplets was also clearly visualized. Puffing behavior of spray droplet observed in this research was quite similar to that of single droplet with a diameter of about 1 mm. Time scale of puffing was about 1/100,000 sec. Comparison of spray droplet diameter of emulsified fuel with that of n-dodecane spray showed that secondary atomization improved spray characteristics.

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Multiphase combustion process of micro PET (polyethylene terephthalate) resin particles is examined by the following two types of experiment; an optical observation of a single particle with different oxygen concentration and that of two particles aligned horizontaly with different initial separation distance. The results show that the occurrence of fire of a single particle is delayed with decrease in oxygen concentration due to reduction of the heat transfer from the flame. With decreasing distance between particles, the flame pattern changes to one marged flame from individual flames because of increase the effect of lack of oxygen.

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We studied numerically the flame spreading phenomena in a narrow circular duct made by PMMA in order to capture the time-depended transport processes during the event. The main aim of this study is to clarify the stability mechanism near the extinction limit (i.e. low Damkohler number limit) which is one of unique feature in this system, which might be different from the conventional flat-plate flame spreading as suggested in our previous works. Numerical model includes time-dependent mass and heat transfer with one-step finite rate of chemical reactions both in gas and solid phase. In this study, it is successfully simulated the nearly steady flame movement under the condition studied. Moreover, it is accomplished to reproduce the two distinctive spreading modes, such as the one belongs in thermal regime and chemical regime, which have already been observed experimentally. Although there is quantitative disagreement between experimental and numerical results, it is confirmed that our numerical model should be satisfactory to capture the qualitative behavior of flame spreading in the narrow duct.

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A volumetric solar receiver receives the concentrated radiation generated by a large number of heliostats. Heat transfer takes place from the receiver solid phase to the air as it passes through the porous receiver. Such combined heat transfer within the receiver, associated radiation, convection and conduction, are investigated using a local thermal non-equilibrium model. Analytic solutions are obtained for the developments of air and ceramic temperatures as well as the pressure along the flow direction. The results show that the pore diameter must be larger than its critical value to achieve high receiver efficiency. Subsequently, there exists an optimal pore diameter for achieving the maximum receiver efficiency under the equal pumping power.

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Heat transfer performance assessment was made for forced convection in a heated tube with a porous medium core and a tube with a wall covered with a porous medium layer, so as to investigate effectiveness of porous material insertion within a tube. Both local thermal and non-thermal equilibrium analyses were carried out for the two cases of partial porous medium filling, to investigate the validity of local thermal equilibrium assumption. It has been found that the local thermal non-equilibrium analysis is essential for the case of forced convection in a tube with a heated wall surface covered with a porous medium layer, whereas the local thermal equilibrium analysis suffices to capture transport phenomena for the case of forced convection in a tube with a porous medium core. In a comparatively low range of pumping power, the heat transfer performance of the tube with a porous medium core is higher than that of the tube with a wall covered with a porous medium layer. However, in a high range of pumping power, the latter performance exceeds the former.

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A novel numerical simulation procedure has been proposed for prediction of local urban climatological phenomena. Buildings and skyscrapers in the urban area were modeled as a collection of porous blocks of prescribed permeability and porosity. A new set of the governing equations based on the volume averaging theory has been derived in which the velocity vector, Exner function, potential temperature and the mass fraction of water are dependant variables. A numerical integration scheme similar to SIMPLE has been developed to solve the set of the equations. Sample calculation results reveal interesting climatological phenomena, associated with the local urban climate.

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Laminar burning velocities for ethanol/air premixed flames were measured in elevated pressure and elevated temperature conditions by using the local angle method which employs particle tracking velocimetry (PTV) to Bunsen flames. Experimental data of laminar burning velocities were compared with numerical results calculated using detailed chemical reaction mechanisms for ethanol oxidation, i.e., the mechanism by Marinov and the mechanism by Saxena and Williams, and the validation of the existing chemical reaction mechanisms was performed under high pressure and high temperature conditions.

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An experimental study of turbulent premixed flames for the CO-H_2-CO_2-O_2 mixtures as a model of syngas oxyfuel combustion was investigated at high pressure. Results showed that the flame front structure of CO-H_2 flames is much fine and have smaller scale compared to CH_4-air flame. The CO-H_2 flames with narrow heat release region tend to be combustion oscillation at premixed-type gas turbine combustor. The bending of S_T/S_L with u'/S_L is not observed for CO-H_2-CO_2-air flames, while, it was observed for other flames and this would be due to the wrinkle of the flame front by turbulence was limited by the flame intrinsic instability.

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Direct numerical simulations of autoignition have been conducted to clarify turbulent combustion mechanisms in homogeneous charge compression ignition engines. Methane-air mixtures at high pressure, 51.3 atm, with spatial inhomogeneity of temperature are investigated by considering a detailed kinetic mechanism. For the case with smaller temperature fluctuations, autoignition occurs in almost whole domain. On the other hand, for the case with larger temperature fluctuations, autoignition occurs at high temperature region and flame propagates from the ignition kernel. The early autoignition and the flame propagation with increasing pressure inhibit the drastic rise of the heat release rate and shorten the ignition delay time due to the increased pressure.

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Hydrogen is a promising fuel and is expected to replace hydrocarbon fuels for its significant potentials to reduce the pollutants and greenhouse gases. It is very important to investigate minimum ignition energy (MIE) on safety standards and ignition process of hydrogen-air mixtures. In this study, the spark ignition of hydrogen-air mixture is investigated by using detailed chemical kinetics and considering the heat loss to the electrode. The purpose of this study is emphasized in the effects of the energy supply procedure and the radius of the spark channel on the MIE.

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To investigate effects of charged species on suppression of soot emission in a hydrocarbon flames, measurement of polycyclic aromatic hydrocarbons (PAHs) in a diffusion flame, applied with a corona discharge, was conducted, employing a laser induced fluorescence (LIF) method using the 3rd harmonic of an Nd:YAG laser as an excitation source. AC corona discharge (14 kHz) of low electrical current was applied to the flame upstream, to preclude effect a change of reaction by corona wind. Due to intensify of the discharge current, increase and decrease in LIF intensity of PAHs was verified.

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This paper describes velocity measurements of the micro-scale three-phase flow containing micro-bubbles and micro-particles in a vertical channel. A Particle Tracking Velocimetry (PTV) technique is used to estimate the velocities of micro-bubbles and micro-particles. The measurement shows that the probability distribution of the bubble location in the vicinity of the wall for the three-phase flow is lower than that for the two-phase flow. The measurement also shows that the RMS value of the bubble fluctuation velocity in the streamwise direction for the three-phase flow is high compared with that for the two-phase flow. This is related to the suppression of bubble motion in the wall-normal direction resulting from the existence of particles.

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This paper presents effects of inclination angle of a heated plate on laminar natural convection flow with sub-millimeter bubbles. The use of thermocouples is applied to temperature measurements and an image processing technique is used to estimate the bubble velocity. For each inclination angle of the heated plate (i.e., φ=80 ° and φ=90 °), the heat transfer coefficient with bubble injection is higher than that without bubble injection. In addition, the heat transfer coefficient with bubble injection for φ=80 ° is higher than that for φ=90 °. The main reason for this is an increase in the mixing effect due to rising bubbles near the heated wall.

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For severe accident analysis in a fast breeder reactor and accelerator driven system, it is predicted that gas-liquid two-phase flow with large density ratio may be formed. We are proposing to develop applicable models for safety analysis. Experiments were performed to measure radial profiles of void fraction and bubble frequency using four-sensor probe method for nitrogen gas-molten lead-bismuth two-phase flow. The experimental results show that the measured void fraction profile changes from wall-peak to core-peak distribution with increasing gas velocity j_g, at j_f=20〜60cm/s and that the bubble breakup is dominant along the flow direction in the present experimental conditions.

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In the refrigeration systems using the two-phase flow ejector, it is important to understand expansion waves and shock waves which are generated at the outlet of nozzle. In this experiment, two nozzles are constructed with and without turning corner at the outlet and experiments are carried out to investigate the characteristics of pressure rising at the outlet caused by oblique shock waves. The evident starting points of pressure rise by oblique shock wave can be measured and interferences with the expansion waves are diminished. The experimental results show that the shock wave angle obtained are close to that predicted by the thermal frozen theory than by the equilibrium theory, while the measured strength of the oblique shock waves show contradictory conclusion.

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Steam injector is a passive jet pump which operates without rotating power source or machinery and it has high heat transfer performance due to the direct-contact condensation of supersonic steam flow onto subcooled water jet, and it has been considered to be applied to the passive safety system for the Next-generation nuclear power plants. The objective of the present study is to determine the operating ranges of steam injector experimentally. In order to achieve this, flow directional pressure distribution is measured with changing the opening ratio of back pressure valve attached at downstream of SI. It is confirmed that pressure distribution at the diffuser increases as the opening ratio of back pressure valve decreases and maximum discharge exists right before the inoperative point of SI. Furthermore, unsteady shockwave which seems to induce the exponential pressure recovery is observed at the upper part of diffuser and it moves toward upstream with decrease of the opening ratio and triggered discharging of water from the drain as well as the inoperative of SI. It is suggested that the maximum discharge pressure of SI is one of key parameters determining the operating range of SI and is measured with changing the inlet condition such as water flow rate and steam pressure in order to predict operating range experimentally.

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Polymer Electrolyte Fuel Cell (PEFC) spread gradually for home use. However, the PEFC is expensive because it uses platinum catalyst and expensive membrane as electrolyte, etc. Therefore, we have developed a new diagnostic system for reducing cost of the PEFC since 2004, and we have already established this system. This paper aims to elucidate the degradation factor distribution of the PEFC in the same electrode to apply this system. As a result, our diagnostics can clarified the degradation factor distribution, and we are going to be able to design a gas channel without degradation, and elucidate degradation mechanism of the PEFC using this system.

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Composition ratio of Ni and YSZ is a primary control parameter to optimize the microstructure of Ni-YSZ cermet anode of Solid Oxide Fuel Cells (SOFCs). In this study, the performance of Ni-YSZ cermet anodes with three different composition ratio, Ni:YSZ = 70:30, 50:50 and 30:70 are experimentally investigated. The 3D microstructure of the tested anodes is directly observed by focused ion beam and scanning electron microscope (FIB-SEM). From the microstructural analysis, Ni:YSZ = 30:70 anode has no active three-phase boundary around anode-electrolyte interface because of the poor Ni connectivity, which results in higher ohmic resistance of the anode.

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The present paper describes the dynamic behavior of a solid oxide fuel cell (SOFC) adopting the numerical modeling. The main topic is focused on fuel starvation occurring as a drawback of load-following operation. The fuel starvation can occur when load increases rapidly. The major factor in the fuel starvation outbreak was studied on several cases of the power output control with the fuel utilization factor and the cell operating temperature control schemes, respectively. They can contribute the fuel starvation prevention in terms of the cell temperature management that prevents the drastic current manipulation for the power output control.

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In the present paper, molecular dynamics simulations of the interface system comprised of self-assembled monolayers (SAMs) and water solvent were performed in order to investigate heat transfer characteristics. Here we focused on the effect of hydrophobicity of SAMs on interfacial heat transfer. Two types of SAM terminal groups, i.e., methyl (CH3-) and hydroxyl (OH-) terminals which have hydrophobic and hydrophilic characters, respectively, were adopted. Nonequilibrium molecular dynamics simulations, in which a constant heat flux was imposed across the SAM interface, were performed to evaluate thermal boundary conductances (TBCs). The result demonstrated that the TBC at the OH-terminated SAM interface is one order of magnitude larger than that at the methyl-terminated SAM interface. Moreover, possible reasons for this significant difference were explored.

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Numerical simulation of heat and fluid flow has been performed to clarify the thermal conditions using for transient one-dimensional numerical simulations of a miniature standing wave thermoacoustic oscillator. Transient one-dimensional equations of continuity, momentum and energy were solved utilizing a TVD scheme. A simple physical model was used for the numerical simulation. As a result, it was found that the consideration of thermal radiation for the numerical analysis of a thermoacoustic oscillator is necessary because the temperature is very high at a heater. It was also found that the heat transfer between heater and wall has great influence on initial sudden temperature changes of a stack.

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The heat exchanger made by fine ceramics like the silicon carbide (SiC) have been widely used in the high temperature and corrosion environment in which the metal can not use. It is difficult to jumboize the heat exchanger made by SiC ceramics from a viewpoint of the cost and reliability. In order to attempt the heat transfer enhancement of the heat exchanger made by SiC ceramics, the heat transfer surface that has nanostructure by carbon nano tubes (CNT) was formed by the surface decomposition of SiC, and a heat transfer characteristic was evaluated. As a result, significant effect of nanostructure surface could not be confirmed. It is thought that change in wettability on heat transfer surface, from water-attracting surface to water-repellent surface, is related by CNT processing.

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Heat transfer characteristics of parallel-, counter-, and cross-flow microchannel heat exchangers are investigated numerically. The heat exchangers are modeled as a three-dimensional conjugate heat transfer problem. The working fluid is air. The governing equations are discretized by the finite volume method and SIMPLE algorithm is used to calculate the velocity field. The numerical results are compared among the heat exchangers with ε-NTU. Heat conduction in the partition wall deteriorates the effectiveness of the microchannel heat exchangers. In addition the parallel-, counter-, and cross-flow microchannel heat exchangers show similar trend with respect to the effectiveness.

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The accident at Fukushima Daiichi nuclear power plant happened on March 11, 2011 revealed that the long station blackout causes a possibility of breakout of nuclear reactors. This accident may occur not only by tsunami or earthquake but also long term absence of operators. The author has proposed a cooling system that can continue cooling the nuclear reactor without external electric power supply or the support of operators. This system is composed of natural convection cooling tower and heat exchangers. Power required to operate the system is supplied by the decay heat of nuclear fuels. This paper describes the performances of natural convection cooling heat exchanger and feasibility of the system.

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In this study, we conduct a two-dimensional numerical analysis of radiative heat transfer in a gas-solid two-phase medium using the finite difference time domain (FDTD) method. In gas-solid two-phase medium such as aerosol, which is suspension of fine solid particles or liquid droplets in a gas, radiative heat transfer process is complicated phenomenon because of multiple scattering and absorption of light by aerosol particles. Since the scattering pattern is affected by the wavelength and scatterer size, it needs to consider wavelength-energy distribution of the incident wave. Therefore, we assume solar radiation and analyze the electromagnetic waves with the wavelength range of 0.1-4 μm, of which energy corresponds to 99% of the total solar radiation energy. Because the wavelength range is divided every 0.1 μm, the Maxwell equations for 40 electromagnetic waves are solved simultaneously. The electromagnetic waves emitted to a perfect columnar conductor are calculated and this method is validated by comparing with results calculating a wave with single wavelength.

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In microwave heating, the spatial relationship between the microwave mode and the internal structure has an important meaning. Using the microwave of TE_<10> mode and frequency of 2.45GHz in rectangular waveguide, we have investigated the effect of the internal structure of the sample on the characteristics of microwave heating, and have indicated the guideline for the optimization of microwave heating by controlling reflected and transmitted waves. It was found that the characteristics of microwave heating in the in-series structure which installed the air layer in the high dielectric object strongly depend on the thickness and the setting position of the air layer.

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The aluminum nitride (AlN) is useful as semiconductor circuit materials, but AlN is fragile and it is difficult to process it. Laser material processing is non-contact processing and it is suitable for the processing of brittle materials. The present study focuses on processing condition and the influence about microprocessing of the AlN by the femtosecond laser. When the pulse number was less than 200 pulse/μm, as the pulse number increased, so depth was deepened. However, processing was delayed over 200 pulse/μm. Tendency of femtosecond laser processing is similar to that of nano second laser processing.

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We present a novel application of the MEMS technology to a non-contact gripper using arrayed spiral air flows, in order to mitigate flow-induced vibration during the levitation of objects. For handling fragile objects such as silicon wafers and solar panels, we employ a gripping technology with continuous air-blowing, which would enable damage-free handling without contamination. MEMS-based grippers in a size of 5 inch square are demonstrated in this study. It is shown that the attraction force is successfully obtained by the negative pressure of a spiral flow in each chamber, and that open holes play an important role in eliminating the interaction between the neighboring chambers and narrowing the holding gap so as to increase the force density over the entire object.

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