Electrophoretic mobility (EPM) of human promyelocytic leukemia cell lines (HL60) during neutrophil differentiation induced by all-trans retinoic acid (ATRA) or dimethyl sulfoxide (DMSO) was measured using microcapillary electrophoresis chips. Prior to EPM measurement of HL60 cells, neutrophil differentiation of the cells was confirmed by morphological classification. Subsequently, EPM of HL60 cells was measured using an on-chip cell electrophoresis system before and after neutrophil differentiation. The EPM changed gradually with the progress of the neutrophil differentiation. From the analysis of experimental data by principal component analysis, it was revealed that there is a strong correlation between morphologic classification and EPM during the neutrophilic differentiation. The present result suggests that on-chip EPM measurement system can be used as a monitoring tool for the cell differentiation.

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We propose a new detecting method of vacuum pressure utilizing reference cells with the similar structure as pixels in the IR(infrared radiation) image sensor of which the sensitivity is greatly depended on the vacuum pressure in the sensor package. This method showed the excellent correlation between the vacuum pressure and output voltage without any additional pirani gauge requiring readout circuit which is generally utilized to detect the vacuum pressure. The proposed method is understood to realize the detection of the package vacuum pressure with detecting infrared radiation as an IR image sensor.

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A novel benzene vapor sensor based on the swelling effect of polymer film is proposed, which is composed of a Si Bridge embedded with piezoresistive Wheatstone bridge and a gas-sensitive thin polymer layer. The sensor relies on the swelling of the thin polymer layer due to the uptake of organic vapor molecules from ambient condition. The swelling of the thin polymer layer leads to bending of the Si Bridge which causes the piezoresistive Wheatstone bridge to produce an output voltage. In this paper silicon rubber as sensing film with good sensitivity and selectivity for benzene is used in the novel vapor sensor. A theoretical model of the interaction between Si Bridge and polymer layer is presented based on elastic mechanics theory. An equivalent transverse gas load is presented. The output expression of the sensor is obtained. The model of the sensor is verified by the experimental results. The relationship between the parameters of thin polymer layer and the sensitivity of the sensor is studied. The effects of ambient temperature on the sensitive character are investigated. The experimental results show that the benzene vapor sensor has good linearity, sensitivity, selectivity and reproducibility.

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We have improved the performance and reliability of an SOI electrostatic MEMS tilt mirror by using a landing island structure in the substrate layer. The landing island is electrically isolated from the substrate layer and has the same electrical potential with the suspended mirror structure. It works as a mechanical stopper to suppress the hysteresis due to the electrostatic pull-in and to avoid the electrical short-circuit between the actuator electrodes. The air-squeezed dumping effect of the landing island has also been found to eliminate the ringing and improve the step response. This structure can be made by the conventional SOI bulk micromachining with two photo masks. We used the new newly developed tilt mirror in a variable optical attenuator and cleared the Bellcore GR1221.

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A photo-ionization detector operated on alternating current using a lock-in amplifier was studied. Output current of covered electrodes with insulator was proportional to concentration of volatile organic compounds. And contamination made little effect on the current value.

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