Carbon fiber (CF)-plastic composites are expected from the view point of light weighting vehicle structures. The
CF/thermoset plastic laminates have low damage resistance to out-of-plane impact as a problem to be solved, because
they behave as a low strength inter-laminar as compared with high-strength in fiber direction. Accordingly it is strongly
desired to develop CF-composite materials based thermoplastics that have higher toughness than thermoset, for vehicle
use. The present paper describes investigation of impact damages through thermoelastic stress analysis (TSA). Lowvelocity
impact test using drop weight was conducted on stitched non-crimp-fabric CF/NY6 composite specimens. Stress
distribution of the specimens under impact loading was monitored by a lock-in thermography system from the opposite
side of the impact direction. The instrumentation system, which had a focal plane array detector, provided a succession
of thermoelastic stress information as a sequence of TSA images at a high rate. The measured stress distribution agreed
well with a theoretical. And also, selecting a contour feature of the stress distribution determined with a suitable level
conformed approximately to the internal damage image that was processed from the TSA images obtained before and
In this study, we develop a new 3D miniature blood vessel searching system by using near-infrared LED light, a CMOS camera module with an image processing unit for a health monitoring system (HMS), a drug delivery system (DDS) which requires very high performance for automatic micro blood volume extraction and automatic blood examination. Our objective is to fabricate a highly reliable micro detection system by utilizing image capturing, image processing, and
micro blood extraction devices. For the searching system to determine 3D blood vessel location, we employ the stereo
method. The stereo method is a common photogrammetric method. It employs the optical path principle to detect 3D
location of the disparity between two cameras. The principle for blood vessel visualization is derived from the ratio of
hemoglobin's absorption of the near-infrared LED light. To get a high quality blood vessel image, we adopted an LED,
with peak a wavelength of 940nm. The LED is set on the dorsal side of the finger and it irradiates the human finger. A
blood vessel image is captured by a CMOS camera module, which is set below the palmer side of the finger. 2D blood
vessel location can be detected by the luminance distribution of a one pixel line. To examine the accuracy of our
detecting system, we carried out experiments using finger phantoms with blood vessel diameters of 0.5, 0.75, 1.0mm, at
the depths of 0.5 ~ 2.0 mm from the phantom's surface. The experimental results of the estimated depth obtained by our
detecting system shows good agreements with the given depths, and the viability of this system is confirmed.
In this study, a vacuum driven blood extraction device for the self-monitoring of blood glucose (SMBG) was newly developed. The health monitoring system (HMS) for SMBG consists of a blood extracting system and a drug delivery system (DDS). Our HMS extracts the blood through a micro-needle and measures the blood sugar level accurately. The main purpose of this work in HMS development are, 1) minimally invasive blood extraction, 2) a handy type automatic blood extraction, and 3) a continuous measurement of the blood sugar level. We adopted a vacuum driven type blood extraction mechanism. The vacuum driven blood extraction unit consists of a) a puncture part to open the vacuum part, b) an extraction part, and c) a measurement part. The puncture and extraction parts consist of a minimally invasive micro-needle, whose inner diameter is less than 100μm and made of titanium alloy, and a vacuum chamber, which is covered by a very thin membrane. A SMA spring and two bias springs are employed to penetrate the blood vessel through the skin with the micro-needle, and to execute the punctuation to slash the membrane in order to open the vacuum chamber. The blood is extracted into the vacuum chamber, seeps into the unwoven cloth according to the capillary principle, and is finally deposited on the blood sugar level sensor. Results show, our vacuum driven blood extraction device succeeded in extracting 12.7μl of human blood within 2 seconds. The blood sugar level was measured successfully by using a glucose enzyme sensor. Finally, the availability of our HMS device was confirmed.
In this study, a sputtering technique for a Bio-MEMS thin film piezoelectric actuator is developed, by employing a newly designed biocompatible piezoelectric material MgSiO3 that has a tetragonal perovskite lattice crystal structure. This crystal structure was designed by using numerical analyses, such as the HSAB rule, the geometrical compatibility assessment and the first principle based DFT calculation. In general, MgSiO3 has an orthorhombic perovskite structure in the nature. Therefore, we try to generate a tetragonal structure by employing 1) the helicon wave plasma sputtering (HWPS) method, which can produce large energy atoms under a low working pressure and easy to control the lattice constant for growing the tetragonal structure of MgSiO3 and 2) a bio-compatible substrate Ir/Ti/Si, to produce a thin film of MgSiO3 tetragonal perovskite. Ir/Ti/Si substrate has better compatibility with MgSiO3 (111) plane, because of its close lattice constant.
An optimal condition of HWPS to generate MgSiO3 tetragonal perovskite structure was sought by using the experimental design method and the response surface method. We found that 1) the substrate temperature and 2) the target composition ratio are significant influent factors for MgSiO3 film generation. In this searching process, we evaluated the properties of MgSiO3 films by 1) the surface roughness measured by AFM, and 2) the chemical compositions measured by XPS, and 3) the crystal structure by XRD. Finally, MgSiO3 thin film was successfully fabricated and the piezoelectric and ferroelectrics properties were measured.
In this study, an automatic blood vessel searching system (BVSS) is newly developed, which is built in the health
monitoring system (HMS) and the drug delivery system (DDS) to extract the blood, evaluates the blood sugar level and
injects the insulin for the diabetic patients. Main subjects of our BVSS development are 1) a transmittance photo imaging
of the finger by using the LED light as a near-infrared light source with peak wave length of 870 nm, and 2) an image
processing to detect the location of the center of the blood vessel cross section.
The sharp edge focus method was applied in our BVSS to detect the depth of blood vessel. We carried out
experiments by using blood vessel phantoms, which consist of an artificial cylindrical blood vessel and skin tissue,
which are made of the teflon tube and the silicone rubber. The teflon tube has the size of 0.6 mm in diameter and is filled
with the human blood. The experimental results demonstrated that the estimated depth, which is obtained by image
analysis corresponding to given depths, shows a good agreement with the real values, and consequently the availability
of our BVSS is confirmed.
The effect of matrix toughness on the fatigue life of polymer matrix composites using plain woven carbon fabrics (pw-CFC) was studied. In order to vary the matrix toughness without changing the inherent cohesion properties such as adhesive strength between matrix and fibers, two different curing agents (acid anhydride and amine types) were used. Static tensile and tension/tension fatigue cyclic loads were applied to pw-CFC specimens. It was observed that the fatigue life was significantly affected by matrix toughness. During the fatigue tests, damage progression was observed intermittently by using a thermo-elastic stress analyzer (TSA). The stress re-distribution occurs due to fatigue damage progression. TSA can identify such stress re- distribution by means of detecting surface temperature amplitude. Highly fatigue-damaged area of pw-CFC was localized if the matrix toughness was high, although moderately damaged area grew all over the specimen. The experimental results indicate that the fatigue life and damage of pw-CFC are strongly governed by matrix toughness.