The endocrine-disrupting chemicals affect the functioning of hormones of animals and are called “environmental hormones". They exist in various environments at very low concentrations in the range of ppt to ppb levels. Thus, highly sensitive determination of environmental hormones with high selectivity is indispensable in regulating the ecosystem, and the instrumentation that allows the on-site analysis of environmental hormones is paid much attention. In this research project, we are aiming at development of new optical immunosensing system for highly sensitive, selective, on-site and simultaneous detection of several environmental hormones at low cost. We report here the results of our research investigations on application of immunosensing technique to highly sensitive detection of environmental hormones, preparation of monoclonal antibodies, fabrication of the microchannel, miniaturization of the surface-plasmon-resonance detector, design of the compact total-sensing-system.

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This paper describes three-dimensional (3-D) microstructure assembly using an external magnetic field. An external magnetic field perpendicular to a substrate lifts a hinged structure by the torque due to the shape magnetic anisotropy. We made micro flap structures (4.5 µm-thick electroplated Permalloy) which have 0.2 µm-thick nickel elastic hinges in various size, and made lift the structures in a magnetic field up to 50 kA/m. We demonstrated that the non-dimensional factor depending on the volume of magnetic material and the stiffness of the hinges determine the sensitivity to the magnetic field. As a result, we realized sequential batch assembly using the difference of the sensitivity. The each two plates 600 µm × 600 µm in size were lifted sequentially, and out-of-plane microstructures were assembled. And the complex out-of-plan microstructures, the regular tetrahedrons 800 µm on a side with a closed linkage were able to assemble by our method.

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Two-dimensional (2D) optical scanner has various applications particularly for building 3D micro optical cross connects (OXC). Most MEMS OXC reported today use electrostatic tilting mirror. However, the mirror-type 2D scanners have an optical alignment issue associated with fiber core deviation. In this paper, we propose a bulk micromachined electrostatic 2D scanner using silicon micro lens as an alternative method for optical scan. The lenses (diameter 260µm) and the driving actuators are integrated on the same layer of a silicon-on-insulator (SOI) wafer. This paper deals with the design, fabrication, and electromechanical characteristics of the bulk micromachined silicon scanner.

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This paper presents a multifunctional sensor with novel structure, which is capable of directly sensing temperature and two physical parameters of solutions, namely ultrasonic velocity and conductivity. By combined measurement of these three measurable parameters, the concentrations of various components in a ternary solution can be simultaneously determined. The structure and operation principle of the sensor are described, and a regression algorithm based on natural cubic spline interpolation and the least square method is adopted to estimate the concentrations. The performances of the proposed sensor are experimentally tested by the use of ternary aqueous solution of sodium chloride and sucrose, which is widely involved in food and beverage industries. This sensor could prove valuable as a process control sensor in industry fields.

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This paper reports the fabrication of a multi-axis accelerometer with piezoresistive detection using the bulk micromachining technique. The evaluation is attempted in the manner of using a computer simulation (FEM) and fabricating the sensors. Two-axis detection sensors were fabricated for this experiment. These sensors were estimated for two views of a ribbed structure diaphragm and a mass shape. The samples consisting of a ribbed structure diaphragm gave higher output signal than that of the sensor with diaphragm only. This result shows that the ribbed structure affords the effective stress distribution to the piezoresistive elements on the rib. On the other hand, the mass shape had influence on the sensing performance and structural strength of the samples. The samples with square shape mass didn't indicate better properties than that of polygon shape. The stress isn't effectively generated on the sensor elements, because the stress concentrates at the edge of mass. The stress at the edge of mass causes destruction to sensors in fabrication process and has a harmful effect on fabrication yield. These results are in agreement with the calculation of computer simulation (FEM) and show that the optimization of the diaphragm structure and the mass shape is important for achieving a high sensitivity and process yield for product development.

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This paper focuses on the many parameters of PCB (Printed Circuit Board) that might affect on heat flow in the PCB. The parameter study found some guidelines that contribute to provide effective cooling PCB structure, and the study also found that the PCB structure affects temperature distribution of the PCB. Such heat transfer brings up many factors, however dimensionless analysis is considered appropriate way to study this complex heat transfer. Non-dimensional correlation between Nusselt number (Nu) and Grashoff number (Gr), dedicated to high-density PCB, was derived in natural convection cooling system. For the verification of the correlation, experimental simulation was performed in basis of several PCB properties. And unique definitions were given to dimensionless numbers.

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This paper presents a dicing method for MEMS devices without dameges during the dicing process. The method is based on bonding and detachment of a glass cap plate by using thermoplastic adhesive. Sand blast technique was used for the fabrication of glass cap plate which has concavities in the depth of 100µm. The thermoplastic adhesive was screen printed on the glass plate. The plate was thermocompression-bonded to silicon wafer at 210°C and diced to individual chips without damages from water or dicing dusts. The chip was mounted in the package while the glass cap was removed at 330°C.

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