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A single-inverted-pendulum model is presented to simulate and predict the passive response of human balance control. This simplified biomechanical model was comprised of a torsional spring and damper, and a lump mass. An estimation of frequency response function was conducted to parameterize the complexity. The frequency domain identification method is used to identify the parameters of the model. The equivalent viscoelastic parameters of standing body were obtained and there was good conformity between the simulation and experimental result.

The functional behaviors of human standing postural control were investigated when they were exposed to long-term horizontal vibration in the sagittal plane. For complexity of human postural control, a useful alternative method that has been based on a black-box approach was taken; that is, where the feedback mechanism was lumped into a single element. A motor-driven support platform was designed as a source of vibration. The AC Servo-controlled motors produced continuous anterior/posterior (AP) motion. The data were analyzed both in the time and frequency domain. The cross-correlation and coherency functions were estimated. Subjects behaved as a non-rigid pendulum with a mass and a spring throughout the whole period of the platform motion, as consistent with the plan chosen for this study.

The reactionary responses to control human standing dynamics were estimated under the assumption that postural complexity mainly occurs in the mid-sagittal plane. During the experiment, the subject was exposed to continuous horizontal perturbation. The ankle and hip joint rotations of the subject mainly contributed to maintaining standing postural control. The designed mobile platform generated anterior/posterior (AP) motion. Non-predictive random translation was used as input for the system. The mean acceleration generated by the platform was measured as 0.44 m/s² . The measured data were analyzed in the frequency domain by the coherence function and the frequency response function to estimate its dynamic responses. The significant correlation found between the input and output of the postural control system. The frequency response function revealed prominent resonant peaks within its frequency spectrum and magnitude. Subjects behaved as a non-rigid two link inverted pendulum. The analyzed data are consistent with the outcome hypothesized for this study.

Multi-walled carbon nanotubes (MWCNTs) were synthesized using catalytic chemical vapor deposition (CVD) method. Oxygen plasma treatment was applied to modify surface state of the CNTs synthesized for improvement of field emission performance. Surface state of the plasma treated CNTs was studied by X-ray photoelectron spectroscopy (XPS). The surface states of the CNTs were changed as a function of plasma treatment time. The oxygen related carbon shift was moved toward higher binding energy with the plasma treatment time. This result implies that the oxygen plasma treatment changes the surface state effectively. While any shift in carbon 1s peak was not detected for the as grown CNTs, oxygen related carbon shift was detected for the plasma treated CNTs. Carbon shift implies that closed CNT tips were opened by the oxygen plasma and reacted with oxygen species. Since the field emission occurs at pentagons or dangling bonds of the CNT tips, the increase of carbon-oxygen bonds plays an important role in field emission behavior by increasing the number of electron emission sites resulting in improvement of the field emission performance.

B, P, and Cs ions were implanted with various parameters into silicon nitride layers prepared by LPCVD. In order to get the maximum impurity concentration at the silicon nitride surface, a high temperature oxide (HTO) buffer layers was deposited prior to the implantation. Alkali ion and pH sensing properties of the layers were investigated with an electrolyte-insulator-silicon (EIS) structure using high frequency capacitance-voltage (HF-CV) measurements. The ion sensing properties of implanted silicon nitrides were compared to those of as-deposited silicon nitride. Band Cs co-implanted silicon nitrides showed a pronounced difference in pH and alkali ion sensing properties compared to those of as-deposited silicon nitride. B or P implanted silicon nitrides in contrast showed similar ion sensitivities like those of as-deposited silicon nitride.

チタニウムテトライソプロポキシド(TIPP)を出発物質として高い導電率を示すチタソ含有プラズマ重合膜を合成し,導電率の変化に基づくガスセソサーとしての機能につい七調べた。その結果,プラズマ重合によって合成したチタン含有有機薄膜は150～300℃ の温度範囲で,メタノール,エタノール,1-ブタノール,t-ブチルアルコール,アセトンなど,酸素と反応する有機可燃性ガスが存在すると,膜の漕電率が速やかに増大する現象を見いだし,これを利用すると導電率の増加により有機可燃性ガスを定量的に測定できることが明らかとなった。このセンサーの応答機構は膜表面の酸素の吸脱着により,導電率が変化するためであると考えられ,その機構について議論した。

In this study, composite materials were put to dry interfacial treatment by use of plasma technology. It has been presented that the optimum parameters for the best wettability of the samples at the time of generation of plasma were oxygen atmosphere, 0.1 torr of system pressure, 100 W of discharge power, and 3 minutes of discharge time. The decrease in surface potential of charged samples by corona discharge indicates that the amount of accumulated electrical charges reduces and the charges that have been injected lessen rapidly when the duration of UV irradiation increases. The surface resistivity and the tensile strength of plasma treated samples, a longer UV irradiation time resulted in decreased insulation.

For thin resistor films with low TCR (temperature coefficient of resistance) and high resistivity, we have prepared the thin films by cosputtering method with pure Ni and Cr targets and studied the effect of the process parameters on the electrical properties. In sputtering process, DC/RF power and pressure are varied as controllable parameters. We have investigated the microstructure and measured the electrical properties. When the Ni/Cr ratios of the deposited thin films were 0.8 /spl sim/ 1.5, the resistivity was 100 /spl sim/ 120 /spl mu/ /spl Omega//spl middot/cm. Below a Ni/Cr ratio of 1.5 (above 40[wt%] of Cr), the TCR became negative. The TCR of the thin films decreased from -30 ppm//spl deg/C to -75 ppm//spl deg/C with increasing Cr content. It is suggested that the composition ratio and electrical properties of thin films can be controlled by variation of sputter process parameters.

For thin resistor film with low TCR (temperature coefficient of resistance) and high resistivity, we have fabricated thin films using the DC/RF magnetron sputtering of 51 wt%Ni-41 wt%Cr- 8 wt%Si alloy target and studied the effect of the process parameters on the electrical properties. Resistivity was 172 [/spl mu//spl Omega//spl middot/cm] and 209 [/spl mu//spl Omega//spl middot/cm] and TCR were -52 [ppm//spl deg/C] and -25 [ppm//spl deg/C] for RF and DC as a power source, respectively. The sheet resistance and TCR increase with increasing the substrate and annealing temperature. From these results, it is suggested that the sheet resistance and TCR of thin films can be controlled by variation of sputter process parameters and annealing of thin film.

In this paper, we investigated characteristics of hexamethyldisiloxane thin films by plasma polymerization. Thin films were prepared by interelectrode capacitively coupled type apparatus and in conditions with carrier gas flow rate of 11 [cc/min], gas pressure of 0.1 [Torr], discharge frequency of 13.56 [MH/sub z/] and discharge power of 30-90 [W]. The relative dielectric constant and dielectric loss tangent of thin films showed 3.212-3.805 and 0.0026 /spl sim/0.0451 in alternating frequency of 10/sup 3/-10/sup 6/ [Hz].

The polymeric cross-linked hydrogel doped with dye 4- nitroaniline was prepared. The nonlinear optical properties of this material has been studied. The optical storage effects and the dynamic lens effects in this dye doped hydrogel under laser radiation have been observed. It is reasonable to show that this dye doped polymer get will find some applications in optical signal processing.