• Geophysics and Geophysical Exploration
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• v.10 no.3
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• pp.183-190
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• 2007

The site effects of seismic stations were evaluated by conducting a simultaneous inversion of the stochastic point-source ground-motion model (STGM model; Boore, 2003) parameters based on the accumulated dataset of horizontal shear-wave Fourier spectra. A model parameter $K_0$ and frequency-dependent site amplification function A(f) were used to express the site effects. Once after a H/V ratio of the Fourier spectra was used as an initial estimate of A(f) for the inversion, the final A(f) which is considered to be the result of combined effect of the crustal amplification and loca lsite effects was calculated by averaging the log residuals at the site from the inversion and adding the mean log residual to the H/V ratio. The seismic stations were classified into five classes according to $logA_{1-10}^{max}$(f), the maximum level of the site amplification function in the range of 1 Hz < f < 10 Hz, i.e., A: $logA_{1-10}^{max}$(f) < 0.2, B: 0.2 $\leq$ $logA_{1-10}^{max}$(f) < 0.4, C: 0.4 $\leq$ $logA_{1-10}^{max}$(f) < 0.6, D: 0.6 $\leq$ $logA_{1-10}^{max}$(f) < 0.8, E: 0.8 $\leq$ $logA_{1-10}^{max}$(f). Implication of the classified result was supported by observing a shift of the dominant frequency of average A(f) for each classified stations as the class changes. Change of site classes after moving seismic stations to a better site condition was successfully described by the result of the station classification. In addition, the observed PGA (Peak Ground Acceleration)-values for two recent moderate earthquakes were well classified according to the proposed station classes.

• Proceedings of the KIPE Conference
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• 2003.07a
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• pp.279-282
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• 2003

In this paper, to apply piezoelectric transformer for PDA backlight inverter, piezoelectric transformer using the composition which $Nb_2O_5$ added into PNW-PMN-PZT ceramics was fabricated as Rosen-type one with the size of $1165mm^3$. And their electrical characteristics were investigated with the variations of load resistance and driving frequency And then, the driving circuit for PDA CCFL(0.6W) which composed of the two MOSFETs connecting in series was manufactured using piezoelectric transformer, VCO and one-chip microprocessor. After driving for 25 min using the proposed circuit for PDA CCFL(0.6W), driving frequency of 214.4kHz, input voltage of 31.78 V and input current of 21.1mA were shown. And then, output voltage of 293.2 V and output current of 2.2mA were shown. At the same time, efficiency of 96.2$\%$ and temperature rise of $3.6^{\circ}C$ were appeared at the piezoelectric transformer.

• Smart Structures and Systems
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• v.2 no.2
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• pp.115-126
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• 2006

The Terra-Scope system is an affordable 4-D down-hole seismic monitoring system based on independent, microprocessor-controlled sensor Pods. The Pods are nominally 50 mm in diameter, and about 120 mm long. They are expected to cost approximately $6000 each. An internal 16-bit, extremely low power MCU controls all aspects of instrumentation, eight programmable gain amplifiers, and local signal storage. Each Pod measures 3-D acceleration, tilt, azimuth, temperature, and other parametric variables such as pore water pressure and pH. Each Pod communicates over a standard digital bus (RS-485) through a completely web-based GUI interface, and has a power consumption of less than 400 mW. Three-dimensional acceleration is measured by pure digital force-balance MEMS-based accelerometers. These accelerometers have a dynamic range of more than 115 dB and a frequency response from DC to 1000 Hz with a noise floor of less than $30ng_{rms}/{\surd}Hz$. Accelerations above 0.2 g are measured by a second set of MEMS-based accelerometers, giving a full 160 dB dynamic range. This paper describes the system design and the cooperative shared-time scheduler implemented for this project. Restraints accounted for include multiple data streams, integration of multiple free agents, interaction with the asynchronous world, and hardened time stamping of accelerometer data. The prototype of the device is currently undergoing evaluation. The first array will be installed in the spring of 2006.

• Journal of Animal Environmental Science
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• v.15 no.2
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• pp.131-138
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• 2009

This study was conducted to find ways to control environment with the difference between body temperature and background temperature based on swine activity, and to apply to the environment control system of swine barns based on the findings. Following are the results. 1. Swine activity related to background temperature was achieved as color images and swine activity status was categorized into cold, comfortable, and hot periods with visualization system (thermal image system). 2. Thermal image system consisted of an infrared CCD camera, an image processing board - DIF (TH3100), an main computer (400Hz, 128M, 586 Pentium model) with C++ program installed. 3. Thermal image system categorizing temperatures into cold, comfortable, and hot was applicable to the environment control system of swine barns 4. Feed intake was higher in cold temperature, and finishing weight and weight gain per day in cold temperature were lower than others (p<0.05).

• Korean Journal of Materials Research
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• v.30 no.10
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• pp.502-508
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• 2020

This paper focuses on the electrical properties and stability against DC accelerated aging stress of ZnO-V₂O₅-MnO₂-Nb₂O₅-Bi₂O₃-Co₃O₄-Dy₂O₃ (ZVMNBCD) varistor ceramics sintered at 850 - 925 ℃. With the increase of sintering temperature, the average grain size increases from 4.4 to 11.8 mm, and the density of the sintered pellets decreases from 5.53 to 5.40 g/㎤ due to the volatility of V₂O₅, which has a low melting point. The breakdown field abruptly decreases from 8016 to 1,715 V/cm with the increase of the sintering temperature. The maximum non-ohmic coefficient (59) is obtained when the sample is sintered at 875 ℃. The samples sintered at below 900 ℃ exhibit a relatively low leakage current, less than 60 mA/㎠. The apparent dielectric constant increases due to the increase of the average grain size with the increase of the sintering temperature. The change tendency of dissipation factor at 1 kHz according to the sintering temperature coincides with the tendency of the leakage current. In terms of stability, the samples sintered at 900 ℃ exhibit both high non-ohmic coefficient (45) and excellent stability, 0.8% in 𝚫E_B/E_B and -0.7 % in 𝚫α/α after application of DC accelerated aging stress (0.85 E_B/85 ℃/24 h).

• The korean journal of orthodontics
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• v.20 no.3 s.32
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• pp.463-498
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• 1990

전기적 자극에 의한 골성장기전의 개념을 이용하여 임상적 효율성을 증진시키기 위한 연구는 현재 교정학을 비롯한 치과영역에서 활발히 진행되고 있는 분야 중의 하나이다. 전기적 자극의 여러 형태 중의 하나인 전자기장과 하악의 기능적 전방 이동을 유도하는 악기능교정장치가 백서의 하악과두 성장에 미치는 영향을 구명하기 위하여 본 연구를 시행하였다. 생후 4주된 Sprague Dawley계 백서 48마리를 대조군 12마리, 실험군 36마리로 나누고, 실험군은 다시 전자기장을 가한 군, 하악골 전방이동 장치를 장착시킨 군, 전자기장과 하악골 전방이동 장치를 병용시킨 군으로 분류하여 각각 12마리씩 실험동물을 배정하였다. 각 군의 실험동물은 15 HZ의 특수 전자기장이나 하악전방이동 자치가 하루10시간씩 작용되도록 특별히 제작한 실험장치 속에 넣어 1주간, 4주간씩 사육하여 희생시킨 후 하악골을 분리하고 연조직을 박리한 후 $10\%$ formalin에 보관하였다. 하악골 길이를 측정하기 위해 0.05mm까지 계측 가능한 캘리퍼를 이용하여 하악과두의 후연에서 이공까지의 거리를 계측하였고, 하악과두를 절제하여 0.5M EDTA에 탈회시켜 파라핀 포매를 하였다. 표본의 절단방향은 시상평면에 평행하게 하여 $6{\mu}m$두께로 연속절단 하였으며, 그 중 중심의 3절편을 취하여 통법에 의한 H-E 중염색을 시행하였다. 하악골 계측과 H-E 중염색 표본을 통한 조직학적 관찰을 통해 다음과 같은 결론을 얻었다. 1. 4주군에서 전자기장만에 노출된 실험군은 대조군에 비해 하악골 길이가 유익성 있게 증가되었다. 2. 전자기장과 하악골 전방이동 장치를 병용한 실험군은 하악골 전방이동장치만을 사용한 실험군에 비하여 하악골 길이가 증가되었다. 3. 전자기장에 노출된 실험군은 전구 연골아세포(prechondroblast)의 증식, 비대연골 세포층의 세포간질 및 연골내 골화층의 석회화가 모두 증가되었다. 4. 본 실험에 사용한 15 HZ전자기장의 주요작용부위는 백서의 하악과두 성장지역 중 연골내 골화의 석회화 지역이며, 또한 이는 하악골 전방이동 장치와 병용시 하악과두 성장을 촉진시킬 수 있음이 관찰되었다.

• Journal of Korean Ophthalmic Optics Society
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• v.1 no.2
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• pp.49-55
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• 1996

Hydrogenated amorphous carbon(a-C:H) films were fabricated by the low-frequency (60Hz) glow discharge of the mixture of methane and hydrogen, and their electrical properties were investigated. We observed that a-C:H films show the persistent photoconductivity(PPC) by illumination of heat-filtered while light for a few seconds. The PPC was about 10 times larger than the annealed dark conductivity. The samples clearly showed metastable characteristics. With increasing illumination times from 1 to 100 min, the annealing activation energy of the PPC was about 0.39eV. The annealing temperature at which the PPC disappeared increasing from $100^{\circ}C$ to $130^{\circ}C$. Illumination longer than 80 min leads to the formation of ${\pi}$ defects and to the decrease of PPC. From these results, we tentatively propose that the states in the ${\pi}$ band act as deep trap centers generating the metastabilities.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.39 no.5
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• pp.8-15
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• 2002

We optimally designed the VCO(voltage-controlled oscillator) with spiral inductor using the MOSIS HP 0.5${\mu}{\textrm}{m}$ CMOS process. With the developed SPICE model of spiral inductor, the quality factor of spiral inductor was maximized at the operating frequency by varying the layout parameters, e.g., metal width, number of turns, radius, space of the metal lines. For the operation frequency of 2㎓, the inductance of about 3nH, and the MOSIS HP 0.5 CMOS process with the metal thickness of 0.8${\mu}{\textrm}{m}$, oxide thickness of 3${\mu}{\textrm}{m}$, the optimal width of metal lines is about 20${\mu}{\textrm}{m}$ for the maximum Quality factor. With the optimized spiral inductor, the VCO with LC tuning tank was designed, fabricated and measured. The measurements were peformed on-wafer using the HP8593E spectrum analyzer. The oscillation frequency was about 1.610Hz, the frequency variation of 250MHz(15%) with control voltage of 0V - 2V, and the phase noise of -108.4㏈c(@600KHz) from output spectrum.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.20-20
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• 2011

It has been known that, under certain conditions, application of low-temperature atmospheric-pressure plasmas can enhance proliferation of cells. In this study, conditions for optimal cell proliferation were examined for various cells relevant for orthopaedic applications. Plasmas used in our experiments were generated by dielectric barrier discharge (DBD) with a helium flow (of approximately 3 litter/min) into ambient air at atmospheric pressure by a 10 kV~20 kHz power supply. Such plasmas were directly applied to a medium, in which cells of interest were cultured. The cells examined in this study were human synoviocytes, rat mesenchymal stem cells derived from bone marrow or adipose tissue, a mouse osteoblastic cell line (MC3T3-E1), a mouse embryonic mesenchymal cell line (C3H-10T1/2), human osteosarcoma cells (HOS), a mouse myoblast cell line (C2C12), and rat Schwann cells. Since cell proliferation can be enhanced even if the cells are not directly exposed to plasmas but cultured in a medium that is pre-treated by plasma application, it is surmised that long-life free radicals generated in the medium by plasma application stimulate cell proliferation if their densities are appropriate. The level of free radical generation in the medium was examined by dROMs tests and correlation between cell proliferation and oxidative stress was observed. Other applications of plasma medicine in orthopaedics, such as plasma modification of artificial bones and wound healing effects by direct plasma application for mouse models, will be also discussed. The work has been done in collaboration with Prof. H. Yoshikawa and his group members at the School of Medicine, Osaka University.

• Journal of Acupuncture Research
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• v.23 no.4
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• pp.149-162
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• 2006

Objectives : The aim of this study is to evaluate the analgesic effect of electroacupuncture on Jogsamni (ST36) in the collagen-induced arthritis rats and investigate the role played by opioid receptor subtypes $({\mu},\;{\delta},\;{\kappa})$ in the antinociceptive effect of electroacupuncture (EA) In the thermal hyper algesia test. Methods : Immunization of male Sprague-Dawley rats with bovine type H collagen emulsified in incomplete Freund's adjuvant, followed by booster injection 2 weeks later induced collagen-induced arthritis (CIA). The thermal hyperalgesia was evaluated weekly with tail flick latency (TFL). In the fourth week after first immunization, EA stimulation (2 Hz, 0.07 mA, 0.3 ms) was delivered into Jogsamni (5736) for 20 minutes. Analgesic effect was evaluated by using the tail flick latency (TFL) after intraperitoneal injection of normal saline, naloxone, naltrindole and nor-binaltorphimine respectively to CIA rats. Results : The results were as follows; 1. The TFL were gradually decreased in CIA as time elapsed after e immunization of arthrogenic collagen and the maximum value was reached between the third to fifth week. 2. EA stimulation on 5736 inhibited chronic inflammatory pain induced by CIA. 3. The analgesic effect of EA was inhibited by pretreatment of ${\mu}-receptor$ antagonist (naloxone),${\delta}-receptor$ antagonist (naltrindole) and ${\kappa}-receptor$ antagonist (nor-binaltorphimine) respectively. Conclusion : Electroacupuncture has an analgesic effect on the CIA rat and has an antinociception mediated by 8, 5, H receptors.