Using molecular dynamics, we simulated behavior of monolayer perfluoropolyether (PFPE) films coated on a solid substrate with respect to the approach and separation movement of another solid surface. Due to the presence of polar end groups, contact to Zdol films and separation from Zdol films occurred at shorter solid-solid distances than Z films. Liquid transfer to the solid surface was also less noticeable for Zdol than for Z. On the other hand, Zdol films exhibited strong adhesion and remarkable hysteresis between the approach and separation processes as compared with Z films.

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We have developed an empirical simulator of the dynamic lateral force microsocpy (DLFM) regulated by scanning tunneling microscopy (STM). This STM/DLFM simulator is applied to simulate the small-amplitude STM/DLFM of the Si(111) 7×7 reconstructed surface. Effects of the dithering amplitude A_<dith> on the STM and DLFM images are simulated and compared with experiments. The simulated two-dimentional patterns of the STM and DLFM images are in good agreement with the experimental ones.

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Atomistic mechanisms of the initial stage of plasticity during nanoindentation are studied by molecular dynamics simulations for three surface orientations of alumina (Al_2O_3) crystal. The simulations predict significant anisotropy and indentation-depth dependence of the hardness value at the nanometer scale. The nanohardness anisotropy is found to arise from orientation dependent dislocation activities.

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The main purpose of the paper is to describe mechanical design of large-aperture disk amplifiers for a high-power solid-state laser. The 400mm-aperture amplifiers use a modular and bottom-access design to facilitate replacement. The key components, such as laser slabs, central flashlamp cassettes, side flashlamp cassettes, reflectors and blast shields, are mounted in line-replaceable units (LRU) which are contained in a clean enclosure to maintain cleanliness. Flowing nitrogen gas is used to cool neodymium glass laser slabs and reduce the amplifier thermal recovery time.

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In high-energy short-pulse laser facilities, the output energy is mainly limited by the size and damaging threshold of compression gratings. Mosaic gratings are an important way to obtain large-aperture gratings. The precision adjustment system designed for a high-energy picosecond laser facility mosaics two planar diffraction gratings. The system has a 9-dimension automatic precision adjustment mechanism and can satisfy the adjustment requirement of the relative positions of two gratings and the position of the whole grating. Based on the stability test, damping material is applied to reduce the dynamic response of the system and improve stability of the mosaic gratings in a long period. After taking the measure, the angle drift in X- and Y-directions is reduced and the specified stability requirement can be met.

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This paper introduces a new system to precisely measure the runout of HDD spinning disks and motors through synchronously acquiring the rotor position signal and the displacements in the axial or radial direction. In order to minimize the synchronizing error between the rotor position and the displacement signal, a high resolution counter is adopted instead of the conventional phase-lock loop. With Laser Doppler Vibrometer (LDV) and proper signal processing, the proposed runout system can precisely measure the runout of the HDD spinning disks and motors with 1 nm resolution and 0.2% accuracy with a proper sampling rate. It provides an effective and accurate approach to measure the runout of high areal density HDDs.

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A piezoelectric ultrasonic microactuator is presented, with a cylindrical stator and slider structure. The length and diameter of the microactuator are about 10 and 1.5 mm, respectively. The stator consists of two piezoelectric ceramic (PZT) tubes connected by a thin film metallic glass (TFMG) pipe, which is fabricated using the rotating magnetron sputtering technique. Traveling wave propagation is generated on the TFMG pipe in finite element method (FEM) simulations. Bi-directional motion of the slider was observed successfully around 600 kHz, and the maximum velocity was about 40 mm/s at 25 V.

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High density magnetic recording technology which is required for a hard disk drive (HDD) should need to become quite narrow track width. Therefore, precise positioning with high speed will be important technology for a spin-stand that is applied to evaluate read and write signal between a magnetic recording head and a recording medium. At the same time, azimuth angle corrections between the head center and a track line should be absolutely necessary. Consequently, a new actuator which acts in one plane has proposed.

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Energy scavenging is one of the solutions for realization of wireless sensor networks. A gyroscopic power generator which generates high speed rotation of permanent magnets using vibrations of human body in daily life is developed. In this report, a prototype generator and its fundamental characteristics based on the analysis of rotor dynamics are presented. High level potential of the generator and its availability to a mobile phone is verified.

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Supplying electric power to information and communication devices is a critical issue for both current mobile networks and coming ubiquitous systems. To achieve this, we focus on dynamic energy conversion systems that utilize human vibrations in daily life. The gyroscopic power generator has a rotor, which moves three dimensionally and spins at a high speed from low frequency vibrations, such as human movements. In this paper, simple equations that indicate the relationships among input vibration, rotor movement, impedance of the output circuit, and the critical conditions for stable rotation are derived. Especially, phase difference is suitable parameter for stability judging. Switching a circuit after watching this parameter through sensing coil enables impedance control.

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Detection of error signals is a key issue in three-dimensional recording with electrical beam control. We propose an improved in-plane error signal detection method using two-dimensional differential push-pull method, which features a suppression of offsets caused by the tilts of an optical recording medium in the in-plane direction. The principle of this method has been experimentally demonstrated.

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Conventional imaging system requires additional mechanical component to focus the object to the image plane. Using aperture coding and image restoration process, all the objects from the macro distance to infinity can be focused digitally not using focus actuator. In this paper, aperture coded optical system which allows digital auto focusing is described.

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The ultimate aim of this research is to improve the robustness of the air gap controller for solid immersion lens (SIL)-based near-field (NF) servo systems against the external shocks. To detect gap error and read-out signals for the SIL and the disk, the air gap control performance must be increased to avoid collisions due to external shocks. We propose an anti-shock air gap control system using a quadrant Q filter and a dead-zone non-linear controller. Experimental results demonstrate that a quadrant Q filter and a dead-zone non-linear controller maintained the optical head with SIL optics distance for a 4.48 G@10 ms shock. Thus the control performance in the presence of external shocks was improved.

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In novel cover-layer-protected solid immersion lens (SIL)-based near-field recording (NFR) optics, we presented superior optical performance by modulating the amplitude and phase in the entrance pupil using annular pupil zones. Using an annular aperture consisting of three concentric annular zones, the 1.45 numerical aperture (NA) cover-layer-protected SIL-based NFR optics achieved improvement of optical resolution. These 1.45 NA optics yielded a full width at half maximum (FWHM) spot size of 0.315λ, a focal depth of 0.82λ, a focused beam spot sensitivity to air-gap distance within the near-field region of 0.04λ, and a sidelobe intensity lower than 7%. In comparison with 1.80 NA, the annular aperture optics achieved 3.5 times longer focal depth and much lower focused beam spot sensitivity to air-gap distance while maintaining the same high resolution.

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We analyzed the characteristic of the electric field in a focal plane consisting of a solid immersion lens (SIL), an air-gap, and a measurement sample for radially polarized illumination in SIL based near-field optics with an annular aperture.

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This paper describes the development of a haptic sensor using a polyvinylidene fluoride (PVDF) film, which is a kind of piezoelectric materials. Output characteristic of PVDF film is similar to one of pacinian corpuscles in human skin. In experiment, smoothness and softness of skin model were measured using the sensor system. After that, the results were compared with physical properties of the objects.

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This paper presents the development of a tactile sensor that is friendly to body tissue and measure stiffness and surface conditions such as sliminess. Active tactile sensing by balloon expansion using fluid is proposed. A balloon is contacted with an object and expanded by using fluid. The sensor probe is developed and the sensor system is assembled. Experimental results on samples with different stiffness and surface conditions show the validity of the sensor.

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This paper describes a development of a polymer sensor using a solid polymer electrolyte (SPE) film. The sensor has a basic structure that a SPE film is sandwiched between thin carbon films and conductive tape is attached on each carbon film. The SPE film has a good flexibility and can be used in air. First output response to deformation is investigated by applying the displacement. Then a curvature sensor using the material is proposed. In experiments, it is found that the proposed sensor is available to measure curvature directly without complex calculations.

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We aims at a body motion instruction system that is expected to work instead of instructors. As a prototype model of the system, we have developed a glove type device using shape memory alloy (SMA) actuators. A subjective assessment experimental result showed that the system could instruct motions which bend each finger.

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This paper describes a sensory feedback system for the intelligent artificial arms. A 3DOF artificial arm, which generates elbow joint flexion/extension motion, forearm supination/pronation motion, and hand open/close, has been designed for an above elbow amputee. These motions are controlled based on EMG signals of the remained active muscles of the user. In the proposed artificial arm, pressure sensors are attached on the surface of fingers to measure the grasping force and estimate the weight of the grasping object. Slippage between the grasping object and the fingers is also detected by the pressure sensors. A DC motor and a vibrator are attached at the connecting part of the artificial arm to the user upper-arm for the sensory feedback.

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There are emerging needs for the manipulation of cellular functions of high-value added cells, which requires such technique as physical handling in single cell level, introduction of foreign substances, measurement of the cell response, fusion, factor exchange among cells, etc. Nanotechnology, based on microfabrication is expected to have high potential in this field. In this paper, our recent research topics, such as on-chip electroporation, electrofusion, and their application to the measurement and alternation of cellular functions, cytosol transplants, are presented.

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In this paper, we proposed the novel method for manipulating DNA fibers on microbridges fabricated by the single mask UV lithography process. Chromosomes were stretched and immobilized on microbridges by the centrifugal force, and the chromosomes could be individually accessible platforms for DNA fiber applications. It was confirmed the validity of the proposed method by applying suspended chromosomes to the FISH analysis.

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We present imaging of the physiological cell reaction of stimulus-responsive cells using a new orifice channel chip. The chip enables tissue-like cell location which cells are aligned along the blood vessels, and designated cells treatment using orifice-channels similar to blood vessels. We successfully demonstrated to observe the stimulus-response in the stimulus-responsive cells (pancreas β cells) using the chip. We provide the new method to observe these cell-reactions

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This paper presents the characteristics of the AC drive of a micro electro mechanical system (MEMS) mirror for suppressing mirror angle drift caused by the charging effect. We measured the stability of a mirror tilt angle when the pulse amplitude modulation drive and the pulse width modulation drive are used as angle control techniques of the MEMS mirror, respectively. Angle stabilities were measured from the optical power by using the reflected light from a mirror. The fluctuations of optical power were less than 0.1 dB for a period of 15 hours with both techniques as against 10 dB with DC drive. Moreover, the pulse width modulation drive uses inexpensive devices and improves the linearity of mirror angle control.

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Generally, a piezoelectric actuator requires continuous dc voltages to keep a certain piezoelectric displacement. This property can prevent from achieving low energy consumptions of a mobile device. The shape memory piezoelectric actuator doesn't need any continuous dc voltages to keep its piezoelectric displacement. The shape memory piezoelectric actuator can be operated by pulse shaped voltage sets. We had proposed the imprint electrical field control to obtain the shape memory effect. However, it has fatigue of the shape memory by continuous drive. In this study, new principle of the shape memory piezoelectric actuator is proposed and demonstrated. The shape memory piezoelectric actuator is realized by asymmetric voltage operation without imprint electrical field. The asymmetric pulsed operation realized in better fatigue endurance than previous study.

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The electrostatically driven scanning micro mirrors are fabricated for the application to laser display. Electrostatic drives using comb electrodes are simple in structure and easily fabricated by conventional MEMS processes as well as inherent low loss. However, a high voltage is needed for the operation. In this paper, in order to operate mirror at a high frequency, a low voltage and with a large rotation angle, we investigate the operation characteristics of micro mirror with vertically driven comb in vacuum. The fabricated micro mirrors have torsional resonant frequencies between 9 kHz and 25 kHz. The optical-scanning angle is in the range from 0.37 to 3.75 degrees in air with ac actuation voltage of 60V. Due to the operation in vacuum, the rotation angle increases by 52 times larger than that in atmospheric air at the same operation voltage, which corresponds the decrease of operation voltage by a factor more than 7 for the micro mirror having 24.5 kHz resonant frequency. The quality factor depending on air damping is also investigated in pressure range from 100 Pa to 10^<-1> Pa.

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A SiN_x-based cantilever type microactuator with length of the order of 1mm was fabricated and evaluated. Multilayered thin films of NdFeB and Ta, with total thicknesses of 3μm, were deposited on the front-end plate of a 3μm-thick SiN_x cantilever by magnetron sputtering. Pt strain gauges were fabricated on the cantilever, acting as a build-in displacement sensor. Positioning control was realized by using a PID controller, with the output from the strain gauge sensor as the feedback signal. The positioning resolution and bandwidth of the actuator were 2μm and 240 Hz, respectively.

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The idea of vibration energy harvesting has attracted much attention recently. To benefit from resonant amplification, the external vibration must be stable enough to match the resonant frequency of a vibration energy harvester. However, in the majority of cases there is no stable ambient oscillation. Here we propose, from the theoretical perspective, a very simple 'intelligent' energy harvesting machine that extracts energy from irregular vibrations; and at the same time retains a high efficiency.

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In this paper, we report a fully microfabricated acoustic sensor for a novel artificial cochlear system. The developed sensor can detect the magnitude and the frequency of acoustic waves, and can convert the acoustic waves to the electric signals without any energy supply. The sensor is composed of a trapezoidal membrane made of P(VDF-TrFE) and a thin film electrode array on it. The membrane is designed to be vibrated by acoustic waves and to convert acoustic waves to electrical signals by virtue of the piezoelectric effect of the P(VDF-TrFE). In addition, the membrane detects the wave frequency according to the position of the resonating place which is realized by the varying membrane's width. To analyze the vibrating characteristics under the fluid-structure interaction, the sensor is mounted on a substrate including a fluid channel which is filled with a silicone oil of the lymph liquid model. The basic vibrating characteristics are evaluated by measuring the spatial distribution and the frequency dependence of the vibrating amplitude at various frequencies ranged from 0.50 to 10 kHz. The result shows that the sensor can realize the frequency selectivity at the frequencies ranged from 2.4 to 8.0 kHz.

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We studied methods for enhancing handling stability of micro-tweezers in terms of tribology. Two items were examined experimentally. One is a method for increasing coefficient of friction on contact surface of the microtweezers. The other is whether making handling force large leads to increase of frictional force in the case of flexible structures like micro-tweezers. As for the coefficient of friction, we put focus on surface roughness of the contact surface processed by DEEP-RIE (ICP etching). We find that coefficient of friction become large by optimizing the surface roughness. As for relation between the frictional force and the handling force, we found that the both were approximately proportional. We think that the handling stability is improved by those methods.

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We present design, fabrication, and characterization of a small (12×12×8mm) movable railway vehicle for sensor-carrying. The millimeter-sized railway vehicle (MRV) was mainly composed of a vibrational structure and three legs. A railway was designed and fabricated to power and guide the MRV. The MRV with legs on the railway was moving due to its high-frequency vibration. FEM simulations were performed to design the legs. Then, the MRV and the railway were fabricated by precision machining. Finally, the MRV was tested. The result shows that the MRV was moving along the railway and its maximum speed was 12.2 mm/s.

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InGaN/GaN p-i-n junction was deposited on GaN/Si template with AlN/GaN supperlattice as interlayer by molecular beam epitaxy. Different surface microstructure of the p-GaN was affected by the amount of Mg flux. Light-emitting diode was fabricated from the p-i-n junction. The crystal properties of InGaN/GaN p-i-n junction and the related light-emitting diode properties were investigated.

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A dual-scale model for head disk interfaces (HDIs) was enabled by considering the incomparability of the air bearing gap and the suspension deformation. Suspension parameters were estimated with a comprehensive FE model. Meaningful results were obtained by simulating the unloading processes with the FEM.

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As the suspension stiffness matrices obtained from an FE model are ready for simulations, experiments are needed to verify the values. Three experiments have been designed and conducted. Transitional conditions for unloading simulations were determined with a hook-like fixture.

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This work presents the numerical simulation of head/disk interface for bit patterned media by the Direct Simulation Monte Carlo method. The effects of geometry of the bit pattern and working temperature on the air bearing force are studied.

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This investigation presents a finite element simulation of contact between a magnetic recording slider and patterned media. The stress distribution due to contact in patterned media is evaluated. The effects of pad radius and different types of filler materials on the stress distribution are studied.

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Recently, the space between the flying head slider and the disk has been reduced to 10nm or less. Consequently, recording media with grooves such as discrete track media (DTM) and bit-patterned media (BPM), are considered to be some of the most promising media for achieving ultrahigh track densities. Thus, it is becoming increasingly important to analyze the static and dynamic characteristics of flying head sliders over DTM/BPM media using the molecular gas-film lubrication (MGL) equation. In this paper, we first use the perturbation method in the frequency domain to obtain not only the stiffness and damping produced by the air film but also the negative stiffness caused by the attractive van der Waals (vdW) force. The perturbation method was applied to a slider with 3 degrees-of-freedom (3-DOF) over an asymmetric groove-slider configuration, which caused a rolling motion in addition to translational and pitching motions. The dependence of the dynamic characteristics such as spacing fluctuations on the groove depth and the frequency were numerically obtained.

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In the latest magnetic storage systems, the space between the flying head and the disk has been dramatically decreased to less than 10 nm in order to realize ultra-high density recording. When the flying-head height is of the same order as the lubricant film thickness, lubricant deformation affects the static and dynamic flying characteristics of the slider. Therefore, it is very important to investigate the deformation and flow characteristics of lubricant on the recording disk, especially dynamic deformation of the lubricant, which suffers from repetitively applied pressure and shear stress from the flying head slider. In this paper, the dynamic behavior of an ultra-thin liquid (lubricant) surface resulting from repetitively applied pressure and shear stress under a vibrating flying head slider are numerically obtained. The dependence of the liquid surface deformation on the frequency of the stresses, the disjoining pressure, and the disk speed are clarified.

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In the latest magnetic storage systems, the spacing between the flying head and the disk has been dramatically decreased to less than 10 nm in order to realize ultra-high density recording. When the flying height is of the same order as the lubricant film thickness, lubricant deformation affects the static and dynamic flying characteristics of the slider. Therefore, it is very important to investigate the deformation and flow characteristics of lubricant on the recording disk. In particular, in heat assisted magnetic recording (HAMR), laser heating of the lubricant changes surface tension distribution, which may cause deformation of the lubricant film. In this paper, we first established temperature and film thickness dependence equation for surface tension. The temperature dependence was obtained by measuring the relation between surface tension and temperature by means of a tensiometer, while film thickness dependence was obtained by theoretical consideration of the van der Waals pressure equation for a multilayer system. By using the steady state long wave equation with consideration to temperature and film thickness dependence of the surface tension, we numerically analyzed the liquid film deformation caused by the temperature distribution. The depression of the liquid was quantitatively obtained.

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The lubricant, perfluoropolyethers (PFPEs), has been modeled and analyzed based on a coarse-grained bead-spring model. A ultrathin lubricant film with a thickness of 1-2 nm is coated on a disk to lubricate the head disk interface (HDI) of hard disk drives (HDDs). The retention performance of the lubricant film is studied, which is important to avoid a direct contact between the head and disk. The replenishment performance is also studied, which is essential to repair the lubricant film ruptured by a contact of the head. Finally, the typical phenomenon of touch down-take off hysteresis during the contact between sliders and disks is confirmed and analyzed because of the nanoscopic interactions in the HDI.

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In this paper, we proposes a calculation method to investigate the surface effect on nanometer scale gas flow. Using this method, the characteristics of gas Couette flow between two parallel plates separated several nanometer are studied numerically. The influence of intermolecular wall potential on the flow velocity and density profile of the Couette flow are significant. The results show that the effects of wall potential on nanometer scale gas flow are important.

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Less than 2 nm thick carbon overcoat was deposited on a hard-disk media using a new filtered cathodic arc (FCA) deposition technique. This carbon overcoat showed high durability and anticorrosion characteristics comparable to those of 3 nm thick carbon overcoat deposited by the conventional plasma-enhanced chemical vapor deposition (PECVD) method. The major problem of utilization of FCA method in high volume manufacturing of hard-disk media is that large amount of particles on the surface. In this study, we have successfully prepared a thin overcoat with ultra-low particle count on the hard disk media surface while maintaining high deposition rate that is essential to have a high throughput in high volume production.

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This paper describes a novel magnetic head positioning mechanism which uses two micro-actuators in order to change contact forces acting on contact pads. Differential of drag forces acting on the two contact pads swings a slider, and this swing motion is utilized as head positioning. In addition, this mechanism can compensate skew angle of a magnetic head against recording tracks. Validity of the proposed mechanism was investigated by a following control simulation and a seek control simulation. Scale model of the proposed mechanism was prepared and its fundamental characteristics were studied in experiments.

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