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Published: September 12, 2009
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Article type: Appendix
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Article type: Index
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A1-A5
Published: September 12, 2009
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Yuki WATANABE, Yuzo FUJITA, Tetsusei KURASHIKI, Masaru ZAKO
Article type: Article
Session ID: T0101-1-1
Published: September 12, 2009
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Woven fabric composites have been used in many industrial applications because they have some advantages of easy handling, high lateral strength, etc. In order to estimate the mechanical properties of off-axis laminate of woven composites by numerical method, the modeling of woven architecture is very important. In this paper, we propose the numerical model of off-axis laminate [0/45] are separated with three multi-scale models. The mechanical properties of off-axis laminate have been analyzed with multi-scale analysis of M^3 method and the numerical results are described.
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Yasumasa NAKANISHI, Kin'ya MATSUMOTO, Masaki WAKABAYASHI, Masaki ...
Article type: Article
Session ID: T0101-1-2
Published: September 12, 2009
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An effect of architecture of fiber reinforcement on the material damping of golf shafts has been investigated. The vibration tests of CFRP shafts with various architecture of fiber reinforcement have been carried out.
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Masahiro ARAI, Kohei KAKU, Takahiro FUKUOKA, Tetsuya MATSUDA
Article type: Article
Session ID: T0101-1-3
Published: September 12, 2009
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Thermo-viscoelastic constitutive equation of carbon fiber reinforced plastic is investigated by numerical approach based on finite element method(FEM) and homogenization theory. The constitutive equation of the CFRP is considered on the Laplace-transformed domain, and it is discussed based on correspondence principle which is satisfied by the each Laplace-transformed elastic moduli. Homogenization theory is employed to estimate the 'homogenized viscoelastic elastic moduli' of the composite composed of matrix resin and carbon fibers. The effect of the temperature on the relaxation moduli of the CFRP laminates are discussed from the results of numerical demonstration in detail.
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Susumu KUMAGAI, Masato HAYASHI, Kazuki HIRO
Article type: Article
Session ID: T0101-1-4
Published: September 12, 2009
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This work investigates influence of boiling liquid expanding vapor explosion (BLEVE) on mechanical behavior of fiber reinforced polymers. R-134a used as pressure-liquefied gas at 273 K was boiled by instantaneous depressurization. A compressor was used to re-liquefy boil-off gas and to achieve a cyclic liquid-vapor condition. Specimens of glass fiber reinforced polymers (GFRP) were immersed in the cyclic condition. After immersion, short-beam three-point bending tests were performed. The obtained load-displacement curves show the influence of the condition on interlaminar shear behavior of GFRP.
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Kazuaki SANADA, Yuta MIZUNO, Yasuhide SHINDO
Article type: Article
Session ID: T0101-1-5
Published: September 12, 2009
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This study examines the interfacial debonding behavior of fiber-reinforced polymers (FRPs) encompassing self-healing and the performance of this self-healing system. Healing is accomplished by incorporating a microcapsulated healing agent and catalytic chemical trigger within a coating layer on the surface of the fiber strands. Self-healing is demonstrated on single edge notched tensile (SENT) specimens of unidirectional FRPs and the healing efficiency was evaluated by the critical fracture loads of healed and virgin specimens. To investigate the release of healing agent from microcapsule during interfacial debonding, a ultra-violet (UV) fluorescent dye was added to the healing agent and post-fracture specimens were examined by a optical microscope under UV light.
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Daero NA, Tetsusei KURASHIKI, Masaru ZAKO, Hayato OKA, Shun-ichi BANDO
Article type: Article
Session ID: T0101-2-1
Published: September 12, 2009
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A total hip replacement which has been made of fiber reinforced plastics is expected for advantages of the freedom of the design parameters. The artificial hip joint cup is required for high reliability of the fixation with bone. In this study, three types of cup with several surface treatments have been prepared, and the torsion-compression test has been carried out for the estimation of initial fixed torque and maximum torque.
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Hayato OKA, Tetsusei KURASHIKI, Masaru ZAKO, [in Japanese], Shun-ichi ...
Article type: Article
Session ID: T0101-2-2
Published: September 12, 2009
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It is important to estimate mechanical properties of pelvis to design for acetabulum cup. The purpose of this study is to estimate mechanical properties of pelvic cortical bone which is dominant for behavior of pelvis. A micro-indentation test for human pelvic cortical bone has been carried out to obtain Young's modulus (E), and E is estimated as a function of bone density (ρ) converted from CT value. To consider an anisotropy of cortical bone, E has been measured in two directions based loading condition. As the results of examination, the pubis which is one of pelvic parts has strong anisotropy in E-ρ relationships. Furthermore, the mechanical behaviors of pelvis under compress loading have been estimated with isotropy and anisotropy model by Finite Element Analysis (FEA). As the results, an anisotropy of pubis has little effect on pelvic mechanical behavior.
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Satoshi HIROTA, Masahiro ARAI, Yuichi SIOIRI, Hiroaki ITO
Article type: Article
Session ID: T0101-2-3
Published: September 12, 2009
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In the present paper, the influence of carbon nanofiber on interlaminer fracture toughness of CFRP investigated using MMB(Mixed Mode Bending) tests. An interlaminer fracture toughness of CFRP laminates under mixed mode state were evaluated using 2-Dimensional boundary element analysis. The laminates made with carbon nanofiber were found to improve fracture toughness. Addition of 20 g/m^2 VGCF was shown to be an optimal content for highest fracture toughness. It was clarified the relationship between hackle pattern and fracture toughness.
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Yoshinobu Shimamura, Toshihiro Chiba, Keiichiro Tohgo
Article type: Article
Session ID: T0101-2-4
Published: September 12, 2009
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It is well known that carbon nanofillers (CNFs) enhance stiffness, electrical conductivity and thermal conductivity of polymers. Alignment of carbon nanofillers in polymers is expected to increase the performances in the aligned direction. Application of alternating electric (AC) field to uncured epoxy including CNFs may cause alignment of CNFs in the electric field direction, and thus unidirectionally aligned CNF/Epoxy composites can be fabricated. In this study, three types of CNFs were used to investigate the effect of the type of CNF on material properties. Thermal conductivities in the aligned direction were measured for various weight fractions of each CNF. Experiment results show that alignment enhances the thermal conductive properties and the type of the CNF affects these conductive properties. In addition, tensile tests were carried out. The results show that alignment affects the mechanical properties.
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Taiki WATANABE, Yasuhide SHINDO, Fumio NARITA
Article type: Article
Session ID: T0101-2-5
Published: September 12, 2009
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This work deals with the nonlinear electromechanical response of 1-3 piezocomposites. The composites contain square or circular piezoelectric rods in an epoxy matrix. Experiments were performed to measure the displacement versus electric field curves. Three dimensional finite element analysis was also conducted to study the electromechanical fields in the 1-3 piezocomposites by introducing a model for polarization switching. Comparison was then made between numerical results and experimental data.
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Kotaro MORI, Fumio NARITA, Yasuhide SHINDO
Article type: Article
Session ID: T0101-3-1
Published: September 12, 2009
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This paper presents the nonlinear electromagneto-mechanical behavior of magnetostrictive/piezoelectric laminated sensors and actuators under magnetic fields both numerically and experimentally. The devices are fabricated using thin Terfenol-D and PZT layers, and the magnetostriction of the devices is measured. A nonlinear finite element analysis is also employed to evaluate the contribution of magnetic domain switching to the second-order magnetoelastic constants in Terfenol-D layer bonded to the PZT layer, and the nonlinear displacement, internal stresses and induced voltage for the magnetostrictive/piezoelectric laminated devices under magnetic fields are discussed.
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Masaki OMIYA, Takeshi KURIBAYASHI, Takuma KOBAYASI
Article type: Article
Session ID: T0101-3-2
Published: September 12, 2009
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We built up the way of fabricating ionic polymer metal composite (IPMC) actuator with palladium electrodes and evaluated the bending response under various temperatures. IPMC consists of a thin Nation^[○!R] membrane sandwiched between two thin palladium plates. The bending response of EPMC actuator was evaluated under the various temperatures. The results showed that the higher the temperature of ionic solvent was, the larger bending response IPMC actuator showed. Moreover, a simple beam model was introduced and compared with the experimental results.
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Tomohiro INO, Hiroaki ITO, Tsutomu KODERA, Masahiro ARAI
Article type: Article
Session ID: T0101-3-3
Published: September 12, 2009
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In the present paper, some experiments for press molding and numerical simulation about micro press molding of glass devices using finite element method is investigated. Thermo-viscoelastic properties of the glass materials were estimated using undirectional compression creep test based on traditional thermoviscoelastic theory. In this study, PYREX and D263 were used as glass materials. Glass micro press molding was carried out with Glassy Carbon mold given to Line & Space patterns machined by dicing. The adaptive condition of molding temperature which given appropriate transcription profile of the glass was investigated. Moreover, numerical simulation for micro press molding of the glass was carreid out by finite element method using universal FEM code (ANSYS ver.10.0). As a result of comparing experimental results with numerical ones, the cross section shape and height of groove profile obtained by FEM approximately agree with experimental value.
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Naohisa ADACHI, Takashi HARA, Takashi MATSUMURA, Yasuo OCHI
Article type: Article
Session ID: T0101-3-4
Published: September 12, 2009
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Recently, because the micro-machine is noticed and electronic equipments are miniaturized and is lightened, a demand for the micro materials increases. However the mechanical properties data of micro materials obviously run short and the evaluation method of micro materials have not been established. Therefore, the establishment of test method for the micro materials is very necessary. In this study, fatigue test method of the fine wire was developed. The tensile tests and fatigue tests were carried out using hard-drawn copper fine wire (Cu-H-wire), annealed copper fine wire (Cu-A-wire) and aluminum fine wire (Al-wire) with the diameter of 200μm. As the results, the tensile strengths of Cu-H-wire, Cu-A-wire and Al-wire were 545, 234 and 259MPa. It was found that the fatigue strengths at 10^7 cycles of Cu-H-wire, Cu-A-wire and Al-wire were 185MPa, 184MPa and 218MPa. Although Cu-H-wire is 2.3times as tensile strength as Cu-A-wire, the fatigue strength at 10^7 cycles of Cu-H-wire is almost equal to that of Cu-A-wire. It was clear from the results that Cu-H-wire was affected by work softening during fatigue test.
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Yoshikazu YAJIMA, Takanobu MATSUMOTO, Ikuo IHARA, Jyunichi UEGAKI, Yos ...
Article type: Article
Session ID: T0101-3-5
Published: September 12, 2009
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In this work, a load-controlled nano-indentation technique with a spherical tip has been applied to the determinations of stress-strain curves of each grain of polycrystalline iron, and its dependence on the crystal orientation has been evaluated. The surface of a polycrystalline iron (99.99%) is polished precisely and used for the specimen. A multiple continuous indentation method is employed for determining the stress-strain curve in elastic-plastic deformation of each grain. It has been found that the estimated stress-strain curves in plastic deformation shows a significant deviation depending on the grain. It is probable that the crystal orientation affects the stress-strain curve of the grain.
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Takaaki NAKAJIMA, Kazuhito SHINTANI
Article type: Article
Session ID: T0101-3-6
Published: September 12, 2009
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Graphene is a single atomic layer of graphite which has two dimensional honeycomb structure. Althogh its structure is very simple, graphene has extraordinary physical properties. Its edge has a characteristic configuration called armchair (AC) or zigzag (ZZ). It is shown that, for round and hexagonal graphene flakes of small sizes, the edge configuration influences their energy in equilibrium. Graphene nanoribbons (GNRs) of various aspect ratios are equilibrated at low temperature. The energies of equilibrated graphene flakes with ZZ edges are lower than the energies of equilibrated graphene flakes with AC edges. Free graphene flakes undergo compressive edge stress, and vibrate at finite temperature. A constrained GNR also vibrates.
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Terumitsu MIURA, Takashi SUMIGAWA, Katsuhiko FUJII, Masayuki KAMAYA, K ...
Article type: Article
Session ID: T0301-1-1
Published: September 12, 2009
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Bending test was performed for a micro-sized cantilever specimen that made at Fe-2wt%Sn alloy and the root of the specimen was set to a grain boundary to investigate a condition for grain boundary fracture as a preliminary test for evaluation of grain boundary strength by using an ultramicro hardness tester. The alloy was heated at 600℃ for 5h to cause grain boundary segregation of Sn. The grain boundary was fractured in the bending test for the specimen made at large angle grain boundary; whereas the specimen made at small angle grain boundary was not. This result indicates the possibility that quantitative evaluation for the strength of embrittled grain boundaries can be attained by adopting this experimental method.
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Takashi SUMIGAWA, TETSUYA Shishido, Takayuki KITAMURA
Article type: Article
Session ID: T0301-1-2
Published: September 12, 2009
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Dominant factor of the crack initiation at the dissimilar interface in nanoscale components, which include an interface between a copper (Cu) thin film with a thickness of 20 nm and a silicon (Si) substrate, is investigated. Crack initiation experiments are conducted for plural components by means of a loading apparatus built in am electron microscope. Interfacial crack initiation and propagation along the Cu/Si interface is recognized by the In-situ observation. Finite element method analyses point out that the crack initiation at the interface edge is dominated by the stress field within 25 nm and that the criterion for the crack initiation is evaluated to be 1125 MPa.
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Yusuke IKEDA, Huy LE VU, Shoji KAMIYA, Joao GASPAR, Oliver PAUL
Article type: Article
Session ID: T0301-1-3
Published: September 12, 2009
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A novel fatigue test technique with gradually increasing stress amplitude was applied to poly crystal line silicon thin films in order to survey possible fatigue degradation in strength in inert environment. The results were compared with the behavior in high humidity environment. It was revealed that even static strength was weakened with high humidity and that fatigue weakening was observed also in inert environment in addition to the strengthening effect with cyclic loading.
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Takuya IGUCHI, Yoshiki GOTOH, Masayoshi TATENO, Mitsuo KOBAYASHI, Kuni ...
Article type: Article
Session ID: T0301-1-4
Published: September 12, 2009
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The evaluation of mechanical properties including static and fatigue behavior is essential issue for developing a reliable micro-sized machine in service operation. But there has been an absence of the standard test procedure for micro-sized materials. Therefore, the evaluation of mechanical properties including reliability and durability has not been performed. In the present study, we have designed and manufactured the fatigue tester for micro-sized materials. Fatigue tests have been performed for aluminum fine wire with 25μm diameter and the S-N diagram has been obtained. It was investigated that the number of cycles to failure showed wide distribution on each cyclic stress revel.
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Tadahiro SHIBUTANI
Article type: Article
Session ID: T0301-1-5
Published: September 12, 2009
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This paper presents the effect of doped Ag on pressure-induced tin whisker formation. Nanoindentation tests were carried out for pure tin and Ag doped tin finishes. Pressure induced tin defects were found near the contact area. Tin whisker formation was mitigated on the surface of Ag doped tin finish. Smaller grain size of Ag doped tin finish make a threshold stress to produce tin whisker high. Creep property was also changed because of doping of Ag. Since stress relaxation occur quickly, lower stresses are generated in the Ag doped tin finish. These two effect can mitigate tin whisker formation. EPMA also revealed that Ag concentrates to the indented area. It suggests that the migration of Ag influences the mitigation of pressure induced tin whiskers.
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Taisuke SUEDA, Takashi SUMIGAWA, Takayuki KITAMURA
Article type: Article
Session ID: T0301-1-6
Published: September 12, 2009
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The purpose of this study is to investigate the influence of the element configuration of thin film consisting of discretely arrayed nanosized elements on mechanical characteristics. Two different thin films consisting of Ta_2O_5 helical nanoelements (nanosprings) are prepared and two types of crack initiation experiments, which possess radically different stress conditions, are carried out. The finite element analyses indicate the crack initiation is governed by the apparent strain of the nanospring, ε', at the edge. It is revealed that the value of ε' is depends on the element configuration of thin film.
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Hiroyuki HIRAKATA, Taku NISHIHIRA, Kohji MINOSHIMA
Article type: Article
Session ID: T0301-2-1
Published: September 12, 2009
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We investigate the friction anisotropy of thin films that consist of ordered titanium oblique nano-columns fabricated by glancing angle deposition (GLAD). Ramp-load scratch experiments are conducted with a rectangular indenter along three different directions: forward, reverse and lateral directions. Strong friction anisotropy was observed on the film surfaces where the friction resistance for the reverse direction is higher than those for the forward and lateral directions. This is due to the deformation anisotropy of constituent nano-columns caused by the geometrical anisotropy.
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Kenji ITO, Hiroyuki HIRAKATA, Kohji MINOSHIMA
Article type: Article
Session ID: T0301-2-2
Published: September 12, 2009
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Self-organized TiO_2 nanotube arrays are formed by anodic oxidization. Nanoindentation experiments with three different indenters (flat punch, cone and triangular pyramid) are conducted to explore the mechanics governing the strength of the TiO_2 nanotubes. Load-displacement responses strongly depend on the tip geometry and the size of nanotubes. A stress-based fracture model considering the graded, porous and discrete structures of the nanotube arrays is proposed, and fracture stress is estimated based on the model. The fracture stresses in the experiments by different indenters are almost the same regardless of the indenter shape, indicating the validity of the model. The model can predict the size effect in strength of the nanotube arrays as well.
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Kimihisa Miura
Article type: Article
Session ID: T0301-2-3
Published: September 12, 2009
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Two solutions of SH transient problem for the elastic half-space and SH transient reflection problem from a micro plane crack lying in the elastic half-space are analytically connected, finally we calculate numerically SH transient response for semi-infinite elastic wave guide subjected to the lateral impact load. The Cagniard method gives the exact solution of an anti-plane deformation problem which SH impulsive load acts on the free surface of an elastic half-space. After having applied the WienerHopf technique for the transient reflection response from a micro plane crack and the method of images for the transient reflection response from the free boundaries of the elastic wave guide, consequently we are obtaining the precise and rational transient responses for an elastic wave guide with several micro cracks.
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Masayuki KAMAYA
Article type: Article
Session ID: T0301-2-4
Published: September 12, 2009
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Although macroscopic behavior of polycrystalline materials is isotropic and homogenous in terms of elastic deformation, the anisotropic property of each crystal produces nonuniform stress and strain at the microstructural level even under a uniform remote stress condition. In this study, in order to quantify the nonuniform stress/strain, a three-dimensional polycrystalline body consisting of 1024 grains of random orientation was subjected to finite element analyses with crystal plasticity constitutive model. It was shown that the stress and strain on the surface of the body was inhomogeneous and variations in the stress and strain were quantified.
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Takahiro SHIMADA, Satoru OKAWA, Takayuki KITAMURA
Article type: Article
Session ID: T0301-2-5
Published: September 12, 2009
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For the investigation of mechanical instability in a large-scale atomic structure, a simplified method is presented that can describe unstable deformation with reduced degrees of freedom by introducing linear elements. The proposed method is applied to a cracked atomic structure under tension, and it can successfully reproduce the minimum eigenvalue of the Hessian matrix of the potential energy before the dislocation emission and its deformation mode near the crack tip. The computational load is considerably reduced in comparison with the original precise method, and this enables us to address the mechanical instability in a large-scale atomic system.
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Momoji KUBO, Kunio SHIOKAWA, Mitsuo YAMASHITA, Yoshihiro SAKAI, Tomomi ...
Article type: Article
Session ID: T0301-2-6
Published: September 12, 2009
Released on J-STAGE: August 01, 2017
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We applied various computational science methodologies such as first-principles calculation and molecular dynamics methods to the clarification of the corrosion process mechanism of turbine blade. We successfully elucidated the corrosion mechanism of Fe surface by CO_2 molecule. Dissociative adsorption of CO_2 molecule was found to be key factor of the Fe surface corrosion by CO_2. The effect of stress on the corrosion mechanism by CO_2 molecule was also clarified. Moreover, we propose that the sulfurization of Fe surface may reduce its corrosion.
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Tsuyoshi IKEHARA, Toshiyuki TSUCHIYA
Article type: Article
Session ID: T0302-1-1
Published: September 12, 2009
Released on J-STAGE: August 01, 2017
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Low cycle fatigue fracture was investigated using the free oscillation of a resonating test device. Rapid rise of the vibration amplitude provides fast fracture in the range of 100 ms. Rise rate of the vibration amplitude could be controlled by the gain setteing of the driving circuit. The results were analyzed based on the crack propagation law assuming linear stress increase. Fatigue lives obtained by this low-cycle fatigue test agreed well with the extraporation of the stress-life line fitted for the results of high-cycle fatigue test.
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Kei Nagayoshi, Shoji Kamiya, Joao Gaspar, Paul Oliver
Article type: Article
Session ID: T0302-1-2
Published: September 12, 2009
Released on J-STAGE: August 01, 2017
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A method of damage based prediction of static strength of MEMS structures fabricated by Bosch process was proposed. Four points bending tests in different bending directions were performed in order to evaluate the distribution of damage-characteristics on the processed surface as a function of position along the etching direction. As a result, the static strength of notched specimens was successfully predicted from the characteristics obtained with the specimens without notch.-
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Yoshinori KAIBARA, Hiroki FUJII, Takahiro NAMAZU, Yasushi TOMIZAWA, Ke ...
Article type: Article
Session ID: T0302-1-3
Published: September 12, 2009
Released on J-STAGE: August 01, 2017
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This paper describes the mechanical characterization of sputtered aluminum-alloy (Al-alloy) film used as a structural material in microelectromechanical systems (MEMS). The environment-controlled uniaxial tensile test system with elongation measurement image analysis function was developed to investigate the material characteristics at temperatures ranging from room temperature (RT) to 358 K. From the quasi-static tensile test results, no specimen size effect on Young's modulus and yield stress was found, whereas the annealing and temperature influences were clearly observed. To investigate mechanical degradation to cycling loading, the cyclic loading tests were conducted under constant stress- and strain-amplitude modes. In constant stress-amplitude mode, stain amplitude increased with an increase of loading cycles. Almost of the specimens fractured during the tests. Meanwhile, in constant strain-amplitude mode, stress amplitude gradually decreased with increasing cycles, but no fatigue failure was found. The cyclic loading and stress relaxation tests revealed that creep deformation was dominant in the degradation of Al-alloy film subjected to cyclic motion.
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Kohei OTANI, Takahiro NAMAZU, Shozo INOUE
Article type: Article
Session ID: T0302-1-4
Published: September 12, 2009
Released on J-STAGE: August 01, 2017
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This paper focuses on evaluating the adhesive strength of Ag-Sn solder-jointed single-crystal silicon (SCS) micro specimens. The exothermic reaction in Al/Ni multilayer film was used as a heat source for melting the solder film. The reaction could generate heat enough to melt Ag-Sn film. To measure the adhesive strength of solder-jointed SCS specimens, we developed the four-point bending tester for minute specimens. The rectangular-solid SCS specimens having a Ag-Sn/AlNi/Ag-Sn multilayered section were prepared by dicing the bonded SCS wafer under various pressure loads in air and vacuum. As a result, fracture strength increased with an increase of pressure load. The strength of specimens bonded in vacuum was higher than that bonded in air.
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Mitsuo KONNO, Tsuyoshi IKEHARA, Takashi MIHARA
Article type: Article
Session ID: T0302-2-1
Published: September 12, 2009
Released on J-STAGE: August 01, 2017
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Development of disk-type MEMS resonators has a great impact on the application in the wireless communication systems by providing the high quality factor and one-chip capability with the semiconductor ICs, due to a vibration type to reduce an air-damping effect and the utilization of the single-crystal or polycrystalline silicon for the structural material. Now, annular disk-type resonators have been researched for the purpose of realizing higher performance MEMS resonator. In this report, MEMS oscillators using this type disk resonator were developed. Oscillator performance and characteristics of circuit design were reported. Furthermore, Experimental results of water vapor adsorption test were presented for demonstrating mass sensing performance of MEMS oscillators using disk-type resonator.
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Yoshitada ISONO, Naoki MATSUZUKA, Takuya HARA
Article type: Article
Session ID: T0302-2-2
Published: September 12, 2009
Released on J-STAGE: August 01, 2017
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This research carried out a semi-empirical analysis of the resonant frequency for fixed-fixed beam oscillators having a non-uniform rectangular cross section, in order to develop a simple and accurate design rule of electrostatic driving MEMS resonators. Finite element analyses (FEA) revealed that the resonant frequency of the oscillators nonlinearly changed from 7 MHz to 17 MHz with an increase of the width of cross section. However, the frequency estimated by Rayleigh-Ritz theory showed the two times value of FEA. This is because the classical theory does not include the notch effect on the bending stiffness, attributed to the non-uniform cross section. This study newly proposed a analytical formula including the notch effect, and then succeeded in estimating the resonant frequency for the oscillator by fitting the formula into FEA. The analytical formula was also able to predict the transmission factor using the equivalent circuit model.
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Hiroyuki TOKUSAKI, Koji SUGANO, Toshiyuki TSUCHIYA, Osamu TABATA
Article type: Article
Session ID: T0302-2-3
Published: September 12, 2009
Released on J-STAGE: August 01, 2017
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This paper reports an electrical equivalent circuit model for describing in-plane two degree-of-freedom comb transducers. The proposed model is valid for any external parameters by building dummy spring into mis model to detect a mechanical displacement. As a result, we can analyze dc operating points by the model so that we need not to change the parameters of the model on changing the connected electrical and mechanical components, such as a dc bias, external force, and the stiffness of a spring. This model was adapted to a resonator and a frequency characteristic of 2DOF comb transducers was well represented by the model.
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Tatsuhiko SUGIYAMA, Yuki NISHIMORI, Hideta OOISO, Michiru Aoyama, Gen ...
Article type: Article
Session ID: T0302-2-4
Published: September 12, 2009
Released on J-STAGE: August 01, 2017
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This paper described a boosting device by MEMS oscillator. Recently, the semiconductor memory such as SRAM proceed rapidly to be installed in the storage medium such as mobile information devices. In the semiconductor memory, the voltage more than the input voltage (1.8〜5V) is necessary for rewriting and erasing the data. Therefore, the boosting circuit with coil and capacitor is used now. However, the boosting circuit is a trouble with energy-saving because the boosting that uses the electrical circuit has the energy loss at the switching. The boosting device by MEMS aims at highly effective conversion. The effect of boost of comb-drive actuator was confirmed by SPICE simulation that used the equivalent circuit. When the input voltage was 1.8V, the output of 14V or more was obtained.
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Kazuhiko SASAGAWA, Akihiko KIRITA, Takehiro ABO
Article type: Article
Session ID: T0401-1-1
Published: September 12, 2009
Released on J-STAGE: August 01, 2017
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A technique of producing metallic nanostructure by utilizing electromigration has been proposed. Electromigration is the phenomenon that the metallic atoms are transported by electron wind due to high current density. A numerical simulation method of nanostructure formation utilizing electromigration was recently developed based on the governing parameter for electromigration damage, AFD^*_<gen.> However, the simulation did not include the term of specimen's damage. In the present study, the numerical simulation method of the nanostructure-production technique is developed considering electromigration damage of specimen, and the effectiveness of the method is shown through the discussion on validity of the obtained constants.
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Yebo LU, Masumi SAKA
Article type: Article
Session ID: T0401-1-2
Published: September 12, 2009
Released on J-STAGE: August 01, 2017
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A method for the fabrication of different shaped Al micro/nanomaterials (MNMs), like micro-belts, thin wires and micro-vertical-rods, based on discharging atoms through controlled holes in electromigration (EM) has been developed. The sample was a passivated polycrystalline Al line with a slit and some holes introduced by focused ion beam (FIB) at the anode end of it. Under same experimental conditions, different shaped Al MNMs were formed corresponding to different sized and shaped holes, from which Al atoms were discharged while current stressing. The mechanism of different shaped Al MNMs growth driven by EM was proposed in the discussion. It was found that the sizes of holes could affect the release of compressive stress coming from accumulation of Al atoms due to EM.
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Yuki NOBE, Hironori TOHMYOH, Masumi SAKA
Article type: Article
Session ID: T0401-1-3
Published: September 12, 2009
Released on J-STAGE: August 01, 2017
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Recently, Al fine materials, e.g., nanowire and micro-ball, have been fabricated by electromigration. In this paper, in-situ observation of discharging process of Al atoms by electromigration was performed in scanning electron microscope. Current density was constant of 2.5MA/cm^2, and heater temperature were changed at 533, 573, 593 and 613K. With increasing in heater temperature, Al atoms started to be discharged earlier, and lager amount of atoms were discharged. In the microscope, discharged atoms didn't form any ordered materials such as nanowires and micro-balls, although arger amount of atoms were discharged as compared with the case in air.
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Xu ZHAO, Masumi SAKA, Mitsuo YAMASHITA, Fumiaki TOGOH
Article type: Article
Session ID: T0401-1-4
Published: September 12, 2009
Released on J-STAGE: August 01, 2017
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A way of testing the electromigration (EM) resistance of different high purities Al based on atomic flux divergence (AFD) method has been proposed in our previous work. With the theoretical analysis, the EM resistance has been clarified to depend on various parameters which are related with the material properties such as diffusion coefficient and grain size. The present research compared the EM resistance of different high purities Al films with the same thickness of 5μm. For these films, the grain size, which is realized as a factor affecting the resistance, was changed compared with the 1μm thick samples, which have been used in the previous work. Finally, according with the analysis by the synthesis of the obtained EM ranking for the 1 and 5μm thick films, the evaluation of the dominant factor, diffusion coefficient, for EM in high purities Al film deposited by sputtering was approached.
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Makoto YASUDA, Hironori TOHMYOH, Masumi SAKA
Article type: Article
Session ID: T0401-1-5
Published: September 12, 2009
Released on J-STAGE: August 01, 2017
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Au, SiO_2, W and Pt were sputtered onto Ag thin film as passivation layers. Stress-induced migration was occurred by heating the sample, and Ag atoms diffused via the interface between Ag thin film and passivation layers to form Ag hillocks. In the present paper, in an attempt to form Ag nanowires by controlling the shape, diameter, and density of Ag hillocks, the effects of coefficient of thermal expansion, Vickers hardness, and adhesion of passivation layers were discussed.
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Yusuke SEKIGUCHI, Yohei SHINADA, Mitsuo NOTOMI
Article type: Article
Session ID: T0401-1-6
Published: September 12, 2009
Released on J-STAGE: August 01, 2017
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In order to improve the properties of hydrogen storage alloy, LaNi_5 thin films and Pd/LaNi_5 multi-layered thin film have been manufactured and investigated. The thin films were made by vacuum deposition method. Hydrogen storage capacities of LaNi_5 powder, thin film, and Pd/LaNi_5 multi-layered thin film were determined by measuring pressure-composition isotherm (PCT) curves. It was found that hydrogen storage capacity of LaNi_5 thin films was smaller than powder form, but heat-treatment and Pd coating improved the capacity. TEM analysis appeared that the structure of LaNi_5 thin films was amorphous and it was crystallized by He atmosphere heat-treatment at 500℃.
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Akifumi FUJIMOTO, Atsushi HOSOI, Yang JU
Article type: Article
Session ID: T0401-2-1
Published: September 12, 2009
Released on J-STAGE: August 01, 2017
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In order to evaluate electrical properties in nanoscale, the new microwave atomic force microscope (M-AFM) probe was studied and the characteristics of the M-AFM probe were evaluated in order to understand the performance of the probe for the topography of materials and the sensitivity for detection of microwave signals. AFM topography of a grating sample was measured by using the fabricated probe. It was found that the fabricated probes have nanometer order resolution. In addition, the amplitude of the reflection coefficient of microwave was measured by approaching an Au-GaAs sample, which has different conductivity, respectively. As a result, the change of the microwave signals between Au and GaAs were observed. These results indicate that the fabricated M-AFM probe has the capacity of measuring the electrical properties of materials in nanoscale.
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Mikio MURAOKA, Sho OKADA, Takahiro ADACHI
Article type: Article
Session ID: T0401-2-2
Published: September 12, 2009
Released on J-STAGE: August 01, 2017
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Stresses in thin films deposited on single-crystalline nanowires induce large permanent bending of the nanowires, which was previously applied to create helical structures such as nanocoils and nanoscrews by one of the authors. The bending strains reach up to a percentage of a few tens. This study was devoted to basic understanding of the bending mechanism by means of molecular dynamics simulation based on Lennard-Jones potential. Two dimensional model of a nanowire, composed of 5-atom thickness and 100-atom length, was analyzed to determine the thermodynamically stable deformation when one side of the surface was covered with a monolayer of film atoms having a misfit lattice and a different bonding energy. The results of the curvature showed significant effects of lattice misfit, rather than the bonding energy. The misfit strain of about 20% was found to meet the coherent interface. This resulted from reduction in strain energy of a film due to the bending. The relatively small curvatures observed under the non-coherent conditions and the effect of the bonding energy were explained by presence of the surface stress.
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Mikio MURAOKA, Yuhki KATSUMATA
Article type: Article
Session ID: T0401-2-3
Published: September 12, 2009
Released on J-STAGE: August 01, 2017
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This study demonstrates measurement of elastic modulus of nanowires by means of atomic force acoustic microscopy with a concentrated-mass (CM) cantilever. CM cantilevers enhance the sensitivity of the contact resonance of a cantilever to a sample elasticity and make ease in evaluating Young's modulus. A relationship between the contact resonant frequency and the effective Young's modulus of sample was determined from measurements of reference surfaces, quartz wafer (Z plane), Si (111) and sapphire (0001). Aggregation of CuO nanowires, which forms a film on a quartz wafer, was prepared by scraping an oxidized surface of a copper wire with the wafer edge. The measurement of contact resonant frequency for the film-like nanowire aggregation resulted in reproducible evaluation of the effective Young's modulus of CuO nanowires
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