통합 검색 | Korea Science

김병호;박성호;김병호
- 한국세라믹학회지
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- 제32권8호
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- pp.881-892
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- 1995
Sol-Gel derived ferroelectric PZT thin films were fabricated on ITO/Glass substrate. Two kinds of rapid thermal annealing methods, R-I (six times of intermediate and final annealing) and R-II (one final annealing after six times of intermediate annealing) were used for preparation of multi-coated PZT thin films. 2500$\AA$-thick PZT thin films were obtained by the R-I and R-II methods and characterized by microstructure and dielectric properties. In case of using R-II, the microstructure was finer than that of R-I and there was no distinguishable difference in dielectric properties of PZT thin films between the R-I and R-II methods. But dielectric properties were enhanced by increasing perovskite phase fraction with increasing annealing temperature. Measured dielectric constant of PZT thin film annealed at 62$0^{\circ}C$ using the R-I method was 256 at 1kHz. Its remanant polarization (Pr) and coercive field (Ec) were 14.4$\mu$C/$\textrm{cm}^2$ and 64kV/cm, respectively.
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김병호;박성호;김병호
- 한국세라믹학회지
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- 제32권7호
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- pp.783-792
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- 1995
Sol-Gel derived ferroelectric PZT thin films were fabricated on ITO/Glass and Si/SiO2 substrates. In order to investigate the effect of catalysts on the densification and crystallization of PZT thin films, a nitric acid or ammonium hydroxide was added to the PZT stock solution at the state of partial hydrolysis reaction. The measured pH for a stable PZT sol was 5.2~9.3. In case of an acid-catalyzed PZT sol, a highly condensed particulate PZT sol was formed by accelerating the hydrolysis reaction. But weakly branched polymeric PZT sol was formed with a base-catalyzed condition. The difference in densification behavior was not found in the pH range of added catalyst, but the refractive index of PZT thin film was increased rapidly as the annealing temperature increased. The PZT thin film annealed at 54$0^{\circ}C$ for 10 min was fully densified and its refractive index was above 2.4. When the annealing temperature increased, the transition from the pyrochlore phase to perovskite appeared at 54$0^{\circ}C$. The base-catalyzed PZT thin film suppressed to form the pyrochlore phase and proceeded effectively to convert the perovskite phase. This was due to the formation of polymeric molecular structure by controlling the hydrolysis and condensation reaction through the additiion of the ammonium hydroxide.
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김병호
- 한국지능시스템학회:학술대회논문집
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- 한국지능시스템학회 2007년도 추계학술대회 학술발표 논문집
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- pp.159-162
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- 2007
The inverse kinematics problem in robotics is an essential work for grasping and manipulation tasks by robotic and humanoid hands. In this paper, an intelligent neural learning scheme for solving such inverse kinematics of humanoid fingers is presented. Specifically, a multi-layered neural network is utilized for effective inverse kinematics, where a dynamic neural learning algorithm is employed. Also, a bio-mimetic feature of general human fingers is incorporated to the learning scheme. The usefulness of the proposed approach is verified by simulations.
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이재훈;이병주;오상록;김병호
- 제어로봇시스템학회:학술대회논문집
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- 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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- pp.1613-1616
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- 1997
In order to develop a human hand mechanism, a 5-bar finger with redundant actuation is designed and implemented. an optimal set of acutator locations and link lengths for the case of one redundant actuator is obtained by employing a composite design index which simulataneously consider several performance indices such as workspace, isotropic index, and force transmission ratio. Each joing is driven by an compact actuator mechanism having ultrasonic motor and a gear set with poeneiometer an controlled by VME Bus-based control system.
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