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Nobuyasu Sugiura
Article type: Article
Pages
195-196
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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Shigeki Mori, Takayuki Hoshino, Goro Obinata, Kazuhiro Ouchi
Article type: Article
Pages
197-198
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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In recent years, an annual rate of an area density increase was keeping 60% in HDD systems approaching more than 20 Gbits/in^2 in commercial base. Such a high-area density is supported by progresses not only of BPI (Bits Per Inch), but also of TPI (Tracks Per Inch). The higher area density than present necessitates a precise positioning mechanism with a high motion speed. In order to realize such a mechanism with stable following and seeking motion, a linear tracking system was tested. We have designed a new liner air bearing system of ideal non-frictional condition. The liner air bearing has also large stiffness toward the seek direction. This system shows higher resonance frequency than that of the rotary type. This system could realize exact track following and the precisely positioning for the future HDD systems.
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Makoto MIYAMOTO, Hideki KUWAJIMA, Toshio INAJI, Kaoru MATSUOKA
Article type: Article
Pages
199-200
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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We propose a new type actuator to suppress the resonance gain in quasi-rigid body vibration mode (QR mode) caused by the stiffness of support bearings. This paper describes a new head actuator for high frequency band. A special design in actuator construction leads to generation of pure torque in the actuator. We applied this actuator for 3.5 inch HDD. The electromagnetic characteristics, mechanical dynamics and performance of the actuator were measured. The results show that the peak gain of quasi-rigid body vibration mode is substantially suppressed with this special design.
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Takenori ATSUMI, Shinsuke NAKAGAWA, Takashi YAMAGUCHI, Yousuke HAMADA, ...
Article type: Article
Pages
201-202
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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In the head positioning control of magnetic disk drives, a bandwidth must be increased to meet greater performance demands. However, one of the barriers to achieving high-bandwidth is the effect of mechanical resonance modes. Accordingly, we have developed a method for designing a high-bandwidth servo controller that takes into account the mechanical resonance modes. This design method uses discrete-time H_∞ synthesis. It is shown that this method can increase the bandwidth by shaping the primary arm-resonance characteristic.
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Itsuro KAJIWARA, Manabu UEHARA, Akio NAGAMATSU
Article type: Article
Pages
203-204
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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A smart structure is composed of the piezoelectric film sensors and actuators in order to achieve the required vibration control performance. H_2 controller is designed with the reduced order model of the smart structure which is obtained by finite element and modal analyses. The control forces are applied by the piezoelectric film actuators and the feedback signals are detected by the piezoelectric film sensors or the accelerometers in the system. The modal control and the displacement control are conducted by selecting the modal coordinates and the physical displacement as the controlled response, resulting in the vibration reduction. Efficient optimization algorithm based on a two step procedure is proposed in the integrated optimization of structural shape and H_2 control system. It is analytically and experimentally verified that the enhanced performance for the vibration suppression can be achieved by the integrated optimization.
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Taichiro YAMASHITA, Takashi YOSHIDA, Junichi TAMAMOTO, Kazushi YOSHIDA ...
Article type: Article
Pages
205-206
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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We have developed a downward paper-sheet separating mechanism using a vacuum. This mechanism separates paper sheets one by one to downward direction. Even when paper sheets of various length are mixed and fed into the sheet feeder, their bottom side is at the same level. By using a gap control roller while detecting the leading edge and the trailing edge of each paper sheet, each paper sheet can therefore be separated in the downward direction so as to minimize the gap between the paper sheets. As the result, the average gap of each paper sheet is shortened and thus throughput is increased.
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Hiroyuki KAWAMOTO, Wiphut JANJOMSKE
Article type: Article
Pages
207-208
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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Theoretical and experimental investigations have been performed on chain formation of magnetic beads in the magnetic field. It is assumed that the chain length is determined as the length when the total (magnetic and kinetic) potential energy of the chain is the minimum. Calculated chain length under this assumption agreed fairly well with the experimental observations that the length was increased in high magnetic field but it was not affected by the bead diameter. Effect of friction and mode of the chain will be considered to improve the model.
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Toshikazu ISHIHARA, Yuko Nakahira, Kazunori Furukawa
Article type: Article
Pages
209-210
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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Mechanical properties of pig liver and spleen were measured in tension and compression test. Test pieces of the liver parenchyma, the liver capsule, and the spleen parenchyma were obtained from edible pigs in order to examine the tensile and compressive strength, stress-strain curve and Poisson's ratio. The spleen tissues are larger than the liver tissues in terms of the strain at the same stress and in maximum strain, but in terms of maximum stress, the liver tissues are larger than the spleen. The difference of the strain at the same stress between parenchyma and capsule are larger in the spleen than in the liver.
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Itaru KOURAKATA, Kozo MORIYAMA, Tsuyoshi TAKANO, Toshiaki HARA
Article type: Article
Pages
211-212
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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Although the embouchure, which means "lip set" for playing wind instruments, is recognized as the most important element for good performance, very little about parameters of it controlled by the player have been cleared and, especially at the field of pedagogy for brass instrument performance, this theme still is in chaos consequently. Considering the essentiality to know the face what occurs in the perioral area of the player during performance, mouthpiece forces and the pressures the teeth receive on its buccal surface from facial muscles were measured. Results of some experiments revealed these evident differences between very advanced and just beginning French horn players; 1) at almost all registers beginners' mouthpiece forces were greater than the advanced. 2) at extreme low register beginner's buccinator and the part of modiolus loosen while the advanced kept its tension.
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Hideki TAKASAWA, Kensaku KAWAKAMI, Shinya MAKI, Toshiaki HARA
Article type: Article
Pages
213-214
Published: July 31, 2000
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The purpose of this study is to investigate the slippage mechanism of the pre-treatment of Smith's fracture and to evaluate the causal relation between the slippage and fracture reposition under palmar/dorsal flexion. A special designed experimental setup was used to simulate palmar/dorsal flexion motion of cadaver wrist and to measure the contact pressure distribution on the radiocarpal joint with pressure sensors. Comparison of the pressure distribution was made between the intact and Smith's fracture simulated. It was shown from the results that the pressure area for the case of Smith's fracture simulated shifted palmar side, and high pressure area partially appeared under palmar flexion motion.
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Hiroaki FUJII, Hiroshi WADA, Takuji KOIKE, Yu YUASA
Article type: Article
Pages
215-216
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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In tympanoplasty, it is essential to understand the condition of the stapes. However, it has been difficult to evaluate stapes mobility in routine measurement. In this study, aiming at the clinical usage in the future, a new measuring system, which enables to measure the stapes mobility quantitatively and easily, has been developed, and the relationships between the load and displacement of the normal and artificially fixed stapes in the guinea pigs and rabbits were examined.
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Emi ICHIBAYA, Keisuke MIYAZAKI, Kenkichi OHBA, Takayuki TSUJI, Toshia ...
Article type: Article
Pages
217-218
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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This study has been performed to evaluate a relationship between drag coefficient and defect area rate of an orifice. The drag coefficient is an index for functional estimation of the defect area rate of the orifice, which can be utilized to evaluate the degree of aortic regurgitation and stenosis. Firstly, we defined the drag coefficient for both of steady and pulsatile flows. Secondly, we have compared the experimental results of the drag coefficient with theoritical one in steady and pulsatile flows. In steady flow, the both results approximately coincide with eachother. In pulsatile flow, they are almost same only at high Reynolds number region. So we consider the defect area rate can be estimated from the drag coefficient.
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Kentaro YANAGI, Kenkichi OHBA, Tsutomu TAJIKAWA, Masashi IWATSU
Article type: Article
Pages
219-220
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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It is important to understand the interaction between deformable surface of creatures and its surrounding flow field. Therefore, we have carried out this study using various cylinder models with elasto-flexible surface to clarify the interaction. The deformation of the surface and the flow field around the model were observed using a laser light sheet visualization method. The visualization result showed that there were three different kinds of traveling waves generated on the surface of any cylinder models, namely, continuously-occurring wave, periodically-occurring wave, randomly-occurring wave at high-speed stream, Especially, periodically-occurring wave was observed to occur at every Karman vortex shedding from the cylinders. In the case that silicone oil was contained in the surface region, the experimental results indicated that wavelength of the traveling wave was 20% shorter than the case of water contained. The traveling velocities were nearly 75% of the main flow velocities. In the case of the continuously-occurring wave the hydrodynamic drag was 20% lower than that of the rigid cylinder and the cylinder model which its flexible-surface was removed.
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Hiroshi MIZUNUMA, Ryou NAKAJIMA
Article type: Article
Pages
221-222
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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In order to reduce hemolysis in a centrifugal pump, wall shear stress on a pump casing was measured using a flush-mounted hotfilm probe. The blood pump was Nikkiso HPM-15. The measured shear stress reached the maximum value at the location of r/R≅0.8 between impellers, and was approximately proportional to the pump rotational speed. At the speed of 3000rpm, shear stress exceeds 300Pa over the region of r/R>0.5. At the high rotational speed, when the red blood cells enter into the thin high shear layer on the casing surface, the sells suffer instant damage, which would be one of the key factors for hemolysis.
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Hitoshi OCHI, Kenkichi OHBA, Makoto KAI
Article type: Article
Pages
223-224
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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Mosquito belongs to the Diptera and its beating is based upon indirect flight muscles. To investigate flapping of indirect flight, we cut their wing in a span direction by two methods; cutting right and left simultaneously and cutting right and left by turns. The results showed that flapping frequency increased with the decrease in wing span. It was suggested that mosquito was flapping by indirect flight muscles. We measured morphological parameter of mosquito wing. An enlarged scale model experiment was carried out using a very low speed wind tunnel under the condition that Reynolds number and Strouhal number were made equal to those of real mosquito. The flow around the wing model moving up and down was visualized using smoke. Unsteady vortices was generated on the upper surface of the model wing in the period of downstroke. We measured circulation by the vortices and calculated lift force on the assumption that the flow was quasi-steady.
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Ryoichi TASHIRO, Nobuyuki KABEI, Hiroyuki KOTERA, Kunimasa KATAYAMA, Y ...
Article type: Article
Pages
225-226
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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We aimed for permanently supplying the electrical energy to an apparatus for in vivo use such as a cardiac pacemaker and proposed and developed an electrostatic (ES) generator that harnesses the motion of the living body. The generating system consists of a battery as an initial charge supply (ICS), a variable capacitor (VC) in which mechanical energy is converted to electrical energy, a capacitor for energy storage and two rectifiers. In this study, ES generator which does not consume electrical energy of the ICS was used. Since high frequency driving of the VC leads to large power generation, it is effective to introduce a resonant phenomenon. The resonator which consists of a honeycomb-type VC, tension coil springs and mass was made. It was possible to generate electrical power of 58[μm] in case of the ICS with constant voltage of 24[V] and a load with resistance of 1.0[MΩ]. We found that use of resonant phenomenon was effective to increase generated power.
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Hidenori HAYASAKI, Fumio NOGATA, Takehiro FUJII, Kazuhiro MATSUI
Article type: Article
Pages
227-228
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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The purpose of this study is to establish the imaging of trabecular archtecture of cancellous bone using ultorasonics because the imaging of architecture allows strong information to diagnose osteoporosis. We obtained the amplitude A-mode signal from medical ultrasonic scanner and distinguished between trabecular bone and bone marrow. This distinction is based on dumping curve, which is named threshold line made from the top points of the amplitude A-mode signal. The image of ceramic specimen and real cancellous bone of cattle femur were made applying the method of imaging proposed here. This imaging may improve the reproducibility and be useful in osteoporosis.
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Shigeru TADANO, Taro OKOSHI, Junichi SHIBANO, Takayoshi UKAI
Article type: Article
Pages
229-230
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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It is well known that bone has a capability to adapt to usual mechanical environment and to reconstruct functionally its structure and geometry. This phenomenon is called as the adaptive bone remodeling. One of the most important mechanical factor of the remodeling is the stress. To generate the bone remodeling, the stress should remain to stimulate the osteocyte in the relative long period. Thus stress will be a kind of residual stress. To verify this assumption, it is a great significance to measure the residual stress in bone tissue. This paper describes a method to measure the residual stress in rabbit's tibia using the characteristic X-ray diffraction. Bone powder with below 45μm diameter was used as non-strained specimen. As a result, it is proved that the residual stress distributes in rabbits' tibia. The residual stress will occur to not macroscopic bone structure but microscopic bone tissue.
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Tomohiro KANAYA, Satoshi ONO, Toshifumi KOSAKA, Katsuyoshi NAGAOKA, Sh ...
Article type: Article
Pages
231-232
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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Takuzo IWATUBO, Mitsumasa MATSUDA, Shozo KAWAMURA, Yoshifumi MIZUMOTO, ...
Article type: Article
Pages
233-234
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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Yoshihisa MINAKUCHI, Yoshimune MISAWA, Kenji NAKAHARA, Shinji OHKI, Ma ...
Article type: Article
Pages
235-236
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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A bone is changing to the optimal shape and trabecula structure in response to the mechanical environment. This paper was investigated to simulate the optimal trabecula distribution in the femur using the growth-strain method applying FEM. We replaced the strain-energy density generated in the femur with the Young's modulus when the external load was added to the femoral head. As a result, the distribution of the femoral trabecula was simulated using the distribution of the Young's modulus. The femoral trabecula where the strain-energy density was large was generated in the large bone density.
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Kosaku KURATA, Hidehiko HIGAKI, Hiromasa MIURA, Teruo MURAKAMI, Yukihi ...
Article type: Article
Pages
237-238
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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Much attention has been focused on the role of mechanical stimuli in bone remodeling because of the clinical needs for bone prostheses and fracture healing. However, little is known about the alterations of bone architecture related to mechanical environments. In this study, rat caudal vertebrae were subjected to daily cyclic loading regime. In order to reveal the influences of morphological alterations and new bone formation to the stress distribution, we estimated Von Mises stresses with three-dimensional finite element (FE) models constructed from micro-CT structural measurements. FE analyses indicated that woven bone formation over periosteum distributed stress concentration caused by external loading. Von Mises stresses in the offset loaded rat distributed uniformly under the analytical offset loading condition. Changes of tissue stress distribution related to adaptive remodeling could be predicted qualitatively by using image-based three-dimensional FE analysis.
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Daisuke KOGAWA, Susumu TOKURA, Ei YAMAMOTO, Hiroshi MIYAZAKI, Kozaburo ...
Article type: Article
Pages
239-240
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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Noritaka YAMAMOTO, Saori OKADA
Article type: Article
Pages
241-242
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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Male Wister rats age 9 weeks weighting 236-280 g were jumped 300 times. After these animals were sacrificed, tensile tests were performed on patella-patellar tendon-tibia complexes. There were no significant differences in the average mechanical properties of patellar tendons between jumping and control groups. In 60 percent (3/5) of the tendons of jumping group, the mechanical properties did not change. In the remaining 40 percent (2/5) of the tendons, on the other hand, the tensile strength and tangent modulus were remarkably smaller than those of control rats. Our previous study demonstrated that in vivo tension in the tendon during jumping increased to 220 percent of that of normal running in a cage. These results indicate that patellar tendon can not adapt if tension exceeds 220 percent of normal level.
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Masaki KABAYAMA, Takahiro OKITA, Sota YAMAMOTO, Eiichi TANAKA, Janusz ...
Article type: Article
Pages
243-244
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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In this paper, in order to investigate strain distribution of MCL, maximum strain at insertion part and midsubstance of ligament was examined. There was no significant difference between the maximum strain at tibial insertion and the maximum strain at femoral insertion at 0.01mm/s, 0.3mm/s, 10mm/s. Although there were no significant differences, the maximum strain at tibial insertion was higher than the maximum strain at femoral insertion at 100mm/s, 300mm/s. In the future, relationship between strain rate and strength of mid-substance of MCL and bone insertion will be examined.
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Toyotaka YADA, Takeshi MATSUMOTO, Masami GOTO, Fumihiko KAJIYA
Article type: Article
Pages
245-246
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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Time sequential impairement in endothelium-dependent and-independent vasodilation of subendocardial arterioles (Endo-A) were evaluated in hypertensive (HT) canine hearts (2-clip and 2-kidney model). Then, changes in asymmetric dimethylarginine (ADMA), an endogenous inhibitor of nitric oxide (NO) and dimethylarginine dimethylaminohydrolase (DDAH), which degrades ADMA were studied in spontaneously hypertensive rats (SHR) and diabetes mellitus rats (DM) in early stage. In an early stage of HT (4week), the endothelium-dependent response of Endo-A was impaired, and in the later stage (12week), both the endothelium-dependent and independent responses of Endo-A were impaired. These sequential changes may be related with the degree of decreased coronary flow reserve in progression of LVH. ADMA was elevated and DDAH activity was decreased significantly in SHR, but not DM. This may indicate that hypertension increased ADMA by reducing DDAH activity, whereas increased DDAH in early stage of DM may compensate for endothelial dysfunction with increased ADMA.
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Shinya NAKAGAWA, Hiroshi MIYAZAKI, Kozaburo HAYASHI
Article type: Article
Pages
247-248
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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Yoshitaka SHIMADA, Ken KOSUGE, Kotaro OKA, Mariko IKEDA, Kazuo TANISHI ...
Article type: Article
Pages
249-250
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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Several types of physiological stimuli increase cytosolic free Ca^<2+> concentration ([Ca^<2+>]i) in endothelial cells (ECs), and the spatiotemporal pattern of the [Ca^<2+>]i mediates the signal transduction from cell surfaces to internal cell organelles. We therefore investigated how mechanical stimuli were transduced to the spatiotemporal pattern of [Ca^<2+>]i increase, with an Atomic Force Microscope (AFM) for stimulating the subcellular domain. Mechanical stimulation resulted in an immediate and transient increase in [Ca^<2+>]i, as depending on not force but deflection of cells. In the subcellular level, fast Ca^<2+> response domains were different between mechanical stimulation and ATP-induced intracellular Ca^<2+> release. The mechanical stimulus-induced fast Ca^<2+> response started at the cell peripheral domains, and its response reduced when extracellular Ca^<2+> was removed. These results indicate that the earliest Ca^<2+> mobilization depends on extracellular Ca^<2+> through stretch-activated (SA) channels and domains of primary Ca^<2+> response reflect the distribution of SA channels.
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Katsuya SATO, Sodai HOSHIAI, Taiji ADACHI, Yoshihiro TOMITA
Article type: Article
Pages
251-252
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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Osteoblastic activities on the bone envelop such as trabecular surface are influenced by local mechanical environment at microstructural level. In vivo and in vitro experiments have been conducted to clarify the influence of mechanical stimuli on the cellular activities under various mechanical environments. In this study, intracellular Ca^<2+> concentration and intercellular Ca^<2+> wave propagation were observed as a cellular response to applied deformation to a single cell with micropipette. Characteristic features of the Ca^<2+> signaling in the osteoblasts under mechanical stimuli, speed and distance of the Ca^<2+> propagating wave, was quantitatively determined. Directional dependency of the response to the mechanical stimulus was examined by applying a slide of the micropipette tip to the cell, which revealed that each osteoblast has sensitive direction to sense the mechanical stimuli.
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Shinji SEO, Toshiro OHASHI, Yasuaki ISHII, Masaaki SATO
Article type: Article
Pages
253-254
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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Hiroshi YAMADA, Tohru TAKEMASA, Takami YAMAGUCHI
Article type: Article
Pages
255-256
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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We proposed a hypothesis to explain the orientation of stress fibers in cultured cells on a silicone membrane under uniaxial cyclic deformation. The hypothesis states that a stress fiber aligns in the direction in which the sum of the length change in the stress fiber under a cyclic deformation is minimal, and that a cell has a limit in the sensitivity to the mechanical stimulus. The length change was focused in all of the process of deformation, while it was focused only at the unstretched and maximally stretched states in the previous hypotheses in the literature. Numerical simulation results described the relationship between the range of uniaxial stretch and the angle of a stress fiber well. It also showed that the limit of sensitivity to the mechanical stimulus predicted a large width of the distribution of fiber angles under a several percent of strain ranges of uniaxial cyclic stretch.
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Terumi INAGAKI, Ryuichi SASAKI, Masahiro AGU
Article type: Article
Pages
257-258
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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As the infrared thermography has a feature that we can diagnose two-dimensional temperature fields nondestructively and simultaneously at every picture element, it has widely been applied to various engineering and medical applications. Therefore, in this paper, a living body was diagnosed by sensing energy emitted from it quantitatively as electromagnetic waves using the infrared thermography. The unsteady fluctuation phenomenon was estimated by analyzing the temperature data statistically or by using the spectrum analysis method. The fluctuation phenomenon representing 1/f fluctuation is mainly focused on linking to human's mind throughout all the study.
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Koji OKANIWA, Takaaki WADA, Masanobu UJIHIRA, Hinako ICHIKAWA, Yumi MA ...
Article type: Article
Pages
259-260
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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The purpose of this study is to assess the vitrified artificial tissue with the effective thermal diffusivity. Human fibroblast cultured into collagen sponge was used for the test artificial tissue, frozen at a cooling rate of 30∿1200℃/min from room temperature to liquid-nitrogen temperature (-196℃). The test chamber (Φ24×4mm) for freezing the test artificial tissue was in contact with a carbon heater that was on a copper block, which was immersed in liquid-nitrogen. The temperature of the test artificial tissue was increased stepwise from -190℃ to -185℃, and then the effective thermal diffusivity was deter-mined by Laplace transform method. After the measurement of the effective thermal diffusivety, post-thaw viability of human fibroblast was measured by trypan blue exclusion assay. As a result, the effective thermal diffusivity decresed and the viability increased with increasing the cooling rate. The decrease of the effective thermal diffusivity and the increase of the viability show the decrease of quantity of intra-and extracellular ice formation in the artificial tissue. Our results demonstrate that the vitrified artificial tissue can be assessed with the effective thermal diffusivity.
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Takaya NAKAJIMA, Hiroshi WADA, Katsuhisa IKEDA, Takeshi OSHIMA
Article type: Article
Pages
261-262
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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Recent experiments have shown that the outer hair cell (OHC) can elongate and contract in response to changes in membrane potential. This mechanical change is suggested to be driven by a voltage-sensitive 'motor' protein embedded in the basolateral membrane of the OHC. However, the motor protein has been unidentified yet. Therefore, in this study, in order to look for candidate genes of the unknown protein, a cDNA library of guinea pig organ of Corti was constructed. After sequencing and tissue distribution analysis, two putative novel genes were found.
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Terumi INAGAKI, Takafumi MATSUI, Koji INUZUKA, Masahiro AGU, Hideo AKA ...
Article type: Article
Pages
263-264
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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Luminous patterns of firefly were experimentally investigated to evaluate the healing effect by using an appropriate statistical analysis and an image processing. This study is for fabricating a hospice space by which people can be healed from many kinds of stress due to various modern human activities. It is revealed from a series of measurements that a 1/f^n fluctuation mode is included in the lumminous pattern of firefly and that there is a possibility that the luminescence plays a significant role in healing people. Therefore, we have always been feeling that the luminescence is so attractive from ancient times.
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Masaki HOSHINO, Kazunori UEKI, Tsuyoshi TAKANO, Toshiaki HARA
Article type: Article
Pages
265-266
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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In this paper, the driving technique at the intersection was investigated and analyzed to study the characteristics of traffic accident caused by aged drivers. The video camera system and DLT (Direct Linear Transformation) method were used to measure the car motion and steering wheel control. The result showed that the aged drivers drives with their inside space widely and that angular velocity of steering motion was faster than young.
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Tatsuya SATO, Mamoru HASHIMOTO, Takeshi YASUI, Tsutomu ARAKI
Article type: Article
Pages
267-268
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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We have constructed a capillary electrophoresis (CES) system using living cells as the sensor tip of CES to monitor the change of cellar environment. In the present system, yeast cell stained with fluorescence dye was applied as the sensor cell. Fluorescence intensity of the probe cell changes according to the change of cellar environment. To confirm the performance of the proposed CES system, the pollutant (Hg^<2+>) and the biological substance (acetylcholine) were applied. Fluorescence intensity of Rhodamine123 (membrane potential sensitive dye for mitochondria), decreased gradually due to effect of the pollutant, while that of Fluo-3 (calcium sensitive dye) increased.
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Naoya SAKAMOTO, Toshiro OHASHI, Masaaki SATO
Article type: Article
Pages
269-270
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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Yumi MATSUMURA, Hinako ICHIKAWA, Sachie MIZUTA, Masanobu UJIHIRA, Koji ...
Article type: Article
Pages
271-272
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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The effect of cell density on the post-thaw viability of cells in cryopreserved artificial tissue was studied. Human fibroblasts were three-dimensionally cultured for 2 days in collagen sponge (Φ20×1mm) as an extracellular matrix to imitate biological tissue (artificial tissue). Different cell densities for the artificial tissue were used, from (10)^4 to (10)^7 cells/(cm)^3. Four artificial tissues were first stacked in a test chamber, then frozen at a slow or fast cooling rate (either 1 or 50℃/min) in a solution of Dulbecco's Modified Eagle Medium, 20% Fetal Bovine Serum, and 10% dimethylsulfoxide, then kept frozen at -196℃ for 2 hours, and finally thawed. Collagen matrix of artificial tissue was resolved by using collagenase. Post-thaw viability of fibroblasts was evaluated by using a trypan blue exclusion assay. The experiments were prepeated, and then the latent heat of artificial tissue (3×3×1mm) during the freeze-thaw process was measured by using a differential scanning calorimeter. Results show that with increasing cell density, the post-thaw viability decreased, whereas the latent heat was constant. With increasing cell density at the slow cooling rate, temperature of the peak latent heat decreased and and the accumulated fraction of latent heat significantly increased, possibly leading to intracellular freezing. Moreover, when the cell density was high, dehydration was obstructed, and thus the number of fibroblasts exhibiting intracellular freezing increased, which in turn led to an increase in latent heat. Therefore, the post-thaw viability decreased as the number of cells exhibiting intracellular freezing increased.
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Toshiro OHASHI, Yasuaki ISHII, Masaaki SATO
Article type: Article
Pages
273-274
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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Michiko SUGAWARA, Hiroshi WADA
Article type: Article
Pages
275-276
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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Recent experiments have shown that the isolated outer hair cell (OHC) can elongate and contract in response to an electrical stimulation. In vivo, the OHC receptor potential in response to acoustic stimulation would drive OHC length changes, and it is estimated that the OHC motility exerts force on the basilar membrane. This OHC motility is suggested to be due to the deformation of the motor protein which distributes along the OHC lateral wall, and the mechanical properties of the OHC lateral wall and the distribution of the motor protein might affect the motility and force production of the OHC. In this stufy, in order to make the effects mentioned above clear, the OHC is modeled as a shell membrane, in which the conformational change of the motor protein is considered, and numerical calculations are carried out.
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Mitsuru IKEDA, Takayuki USUDA
Article type: Article
Pages
277-278
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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The existing method to measure the contact force between pantograph and contact wire does not deal with the horizontal component, which the authors believe to have important information on current collection conditions. So the authors propose a new method to measure it based on the measuring the torsion of the panhead with strain gages. This method can also estimate the vertical component of the contact force with the same strain gages concurrently. This paper introduces this method and describes the results of an excitation test to estimate its measuring accuracy. The test results show that the horizontal component of the contact force up to 20Hz can be correctly measured together with its vertical component.
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Junji Kondo, Yoshiaki TERUMICHI, Yoshihiro SUDA, Kiyoshi SOGABE
Article type: Article
Pages
279-280
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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The system under consideration in this report is composed of a wheel and a flexible rail fixed at the both ends. Modeling and formulation for such a system are discussed, considering about the following assumptions; The motion of the wheel is constrained in x-y plane. Slip of a wheel is ignored. On the other hand, the rotation of the wheel, the linear contact stiffness between the wheel and the rail, and the large rotation and deformation of the rail are considered. The expression of contact constraints is proposed, using that the distance between the contact points and the gravity center of the wheel is function of the time. The calculation results agreed with experimental ones approximately.
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Katsuya TANIFUJI, Atsushi MORIYAMA
Article type: Article
Pages
281-282
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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In the recent rolling stocks, mechatronics technology has been applied to many functions, and its usefulness was proved in various occasions. And now the saving of cost is asked eagerly in the maintenance of track and rolling stock, then it is expected that the mechatronics technology will be applied for the improvement in curve negotiation of future trains. In order to reduce the lateral force between wheel and rail during the curve negotiation, some kinds of bogie truck with actively steered wheelsets have been investigated. This paper deals with a perspective about the actively steered trucks, and examines the effectiveness of them. One of the active steering trucks employs a control law based on the self-steering ability of wheelset, measuring the relative yaw angle between the wheelset and the bogie frame. It is seen theoretically that the curving performance can be made better with active steering trucks of each kind. However, from the view point of running safety, it seems to be still not easy to put the active steering to practical use. Then, further research for ensuring the reliability of control system will be needed in future.
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Taichi SHIIBA, Yoshihiro SUDA
Article type: Article
Pages
283-284
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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This paper describes a new concept of deriving the analysis model for real-time simulation from the model of multibody systems, and presents suitable algorithm for real-time simulation. For real-time simulation, it is shown that the approximation of constraint equation and the transformation of coordinate in equations of motion are effective for reducing calculation. By numerical simulations of automobile, it is shown that the proposed real-time method achieves high-speed calculation with satisfactory accuracy.
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Takamitsu SASSA, Toshiro ONO, Noriaki TSUBOSAKA
Article type: Article
Pages
285-286
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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Recently, the crashworthiness provision of the railway cars has been required worldwide. Using the mechanical dynamics analysis code ADAMS, the simulation element models of the carbody end structure (crushable zone) and the coupler and draft gear between cars have been developed, and applied to the crash simulation of train set and a truck. The simulation adapting 15 cars train set indicated the good results, that is, the behavior of cars, crushable zones, and draft gears was shown in detail.
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[in Japanese], [in Japanese], [in Japanese], [in Japanese]
Article type: Article
Pages
287-288
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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Despite a recent need for the improvement of train crashworthiness, few design methods have been proposed. To establish it, we tried to introduce the concept of "Crashable body structure" to the design of train bodies in the previous reports. There a train car with crashable zone was modeled by nonlinear spring and mass systems. Here we adopted a closer nonlinear spring and mass model to the real train structure, and propose a method to determine the parameters of the model by solving such an inverse problem as to have the same dynamic properties of the previously optimized simple model. And in comparison with the results of the inverse problems we considered an optimization problem by using the same closer model. Then we solve the problem by two different optimization methods and find strengthes of nonlinear spring in the crashable zones as to minimize the maximum decelerations evaluated in the center of gravity of the car. In several numerical examples, impact decelerations were reduced, and passenger zones could be maintained enough spaces not to injure passengers by the proposed method.
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Shin MORISHITA, Yuji NISHIYAMA, Koichi KURIYAMA, Michiyo OHGAMA
Article type: Article
Pages
289-290
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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This paper describes a traffic flow simulator in a parking area of large-scale store and surrounding road network by Cellular Automata. In order to avoid the traffic jam, it is important to investigate the traffic flow of the road network by simulation under various conditions. In the present paper, Cellular Automata was introduced in modeling the traffic flow. The parking area and surrounding road network were divided into cells, on which cars defined as one of state variables moved in relation to other state variables on neighboring cells along discrete time step. The simulation was carried out under several situations of the road network connections and the traffic quantity. As a result, the traffic flow of a road network including parkings could be simulated under various conditions of road and traffic.
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Atsushi MORIYAMA, Katsuya TANIFUJI
Article type: Article
Pages
291-292
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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In the estimation about curving performance of the railway vehicle, it has been pointed out that worn profiles of rail and wheel are required for modeling of contact condition between rail and wheel. In this study, "N-wheel-profile" which is designed to be similar to the worn wheel is used to create worn rail profile, considering that worn rail profile has the similar shape to that of worn wheel profile. Here, worn rail profiles are modeled both for tangent track and curved one. The characteristics of created worn profiles are examined by using effective conicity and rolling radius difference, and these worn profiles are introduced to the simulation of curving vehicle. Finally, the effect of worn rail on the curve negotiation is evaluated by using simulation results.
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Nobuhiro OHSUKA, Motomu YOKOMORI, Sigeki YAMAGUTI, Takio OHYA
Article type: Article
Pages
293-294
Published: July 31, 2000
Released on J-STAGE: August 01, 2017
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When a motorcycle runs with hand-free riding, tha change in the steering angle is related to tha vehicle body bank angle, which is influenced by the disturbance of road surface and controlled by the rider's lean angle. In this report, the motion of the rider who maintains the upright stability of a motorcycle in hand-free running at a low speed is mainly examined by measuring the vehicle bank angle, rider's leaning angle and steering angle.
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