• 대한구순구개열학회지
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• 제7권1호
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• pp.1-16
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• 2004

본 연구에서는 구순접합술의 효과를 알아보기 위하여, 일측성 완전구순열을 가진 5명의 환아에서 Millard의 high haU-underminded adhesion과 Seibert 의 lip adhesion을 이용한 구순접합술후 Millard 변법을 이용한구순성형술을 시행하였다. 구순접합술은 상악치조분절 간의 관계를 개선해 주고 구순성형술을 쉽게해주며 최종적인 구순성형술 후 더욱 좋은 결과를 나타냈다. High kalf-underminded adhesion과 Seibert의 lip adhesion은 둘 다 넓은 구순열을 하는데 유용한 방법이며, 특히 Seibert의 lip ahesion은 강한 접합력을 얻을 수 있고 변위된 비중격의 개선 효과가 있으며 보다 심미적인 상순의 연속성을 얻게 해 주었다. 이상의 결과에서 넓은 완전구순열 환아에서 구순성형술에 앞서 구순접합술을 시행하면 상악치조분절 간의 관계를 개선시키고 구순성형술 후 최종적인 결과를 향상시킴을 알 수 있다.

• 대한치과보철학회지
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• 제41권3호
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• pp.271-287
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• 2003

Statement of problem: Resonance frequency analysis (RFA) has been increasingly served as a non-invasive and objective method for clinical monitoring of implant stability. Many clinical studies must be required for standardized baseline data using RFA. Purpose: This study was performed to evaluate RFA value changes in two stage surgery group and one stage surgery group in patients. Material and method: Forty-seven mandibles in consecutively implant installed patients were selected for this study and 141 fixtures were installed. Ninety-three fixtures were double threaded, machined surface design ($Br{\aa}anemark^{(R)}$ MK III, Nobel Biocare AB, Goteborg, Sweden) and 48 fixtures were root form, threaded, HA-coated surface one ($Replace^{TM}$, Steri-Oss/Nobel Biocare AB, USA). Among those, each 10 fixture was installed in one stage group patients. ISQ values were measured using $Osstell^{TM}$ (Integration Diagnostics Ltd. Sweden) during fixture installation, at healing abutment connection and in the loading period for two stage surgery group patients and during at each 4, 6, 8, 10, 12week and in the loading phase for one stage surgery group patients and evaluated the changes according to the time and fixture type. Results: In two stage surgery group, mean and SO of ISQ values of machined surface implants were $76.85{\pm}3.74,\;75.76{\pm}5.04,\;75.73{\pm}4.41$ and those of HA-coated surface implant were $75.05{\pm}6.23,\;77.58{\pm}5.23,\;78.32{\pm}4.29$ during fixtures installation, at healing abutment connection and in the loading period, respectively. In one-stage surgery group, the ISQ values of machined surface and HA-coated surface implants decreased until 4 or 6 week and maintained at plateau for 1-3 week and increased to the loading period. Conclusions: Machined and HA-coated surface implants showed minimal ISQ changes with time if they were installed at the sites showing at least intact cortical plate and good bone qualities. And HA-coated implants had a tendency to show somewhat increased ISQ values with time.

• KSBB Journal
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• 제21권3호
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• pp.224-229
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• 2006

전산모사 프로그램인 FEMLAB을 이용하여 chiral center를 가지고 있는 racemate인 ibuprofen의 R-form과 S-form의 분리 전산모사 결과와 Kromasil KR100-5CHI-TBB 칼럼을 사용하여 HPLC를 통한 실험데이터를 비교 분석하였다. Hexane/t-BME/acetic acid(45:55:1 v/v%)의 이동상의 조건에서 이론단수(number of theoretical plates), 이론단높이(HETP; Height Equivalent to a Theoretical Plate)을 구하여 축방향 확산계수($Deff_i$)를 계산하였다. PIM(Pulsed Input Method)을 사용하여 분석한 결과 ibuprofen의 농도가 증가할수록 Langmuir 등온흡착식을 따르는 비선형 거동을 보였고, 각 농도에서의 체류시간($t_R$)과 phase ratio를 이용하여 비경쟁적 Langmuir 등온흡착식의 매개변수를 추산하였고, 이 매개변수를 이용하여 경쟁적 Langmuir 등온흡착식을 결정하였다. 실험을 통해 얻은 데이터를 FEMLAB 적용하여 등온흡착식의 변화에 따른 용리띠의 변화와 두 성분이 컬럼을 이동하는 동안 두 성분간 분리 과정을 관찰하였다. Ibuprofen의 농도, 유속을 변화시키면서 실험결과와 전산모사결과를 비교한 결과 실험결과와 전산모사결과가 비슷한 경향성을 보였다. 이와 같이 FEMLAB 전산모사 프로그램의 실험적용 가능성을 확인하였고. 실험과 일치하는 전산모사데이터를 얻기 위해서 고정상내의 세공에서의 물질전달을 포함하는 물질수지식의 적용과 비선형 흡착평형식에 대한 좀 더 정확한 식이 요구된다.

• 한국세라믹학회지
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• 제39권9호
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• pp.851-856
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• 2002

산화몰리브덴($MoO_3$)이 첨가된 산화크롬 용사코팅층을 제조하여 산화몰리브덴의 첨가에 따른 고온(450$^{\circ}C$)에서의 플라즈마 용사코팅층에 마찰, 마멸특성을 조사하였다. 마찰, 마멸 특성에 대한 실험을 위하여 왕복동 마멸시험장치를 사용하였다. TEM을 이용하여 코팅층의 미세 구조와 각 상들의 조성을 살펴보았다. 분석 결과에 의하면 산화몰리브덴이 입계로 분산되어 있어 코팅층의 경도와 밀도의 증가가 발생하였다. 마멸시험후 마멸면의 물리적 변화와 화학적 조성의 변화를 SEM와 XPS를 통하여 살펴보았다. 산화몰리브덴이 첨가된 코팅층에서 마찰계수의 감소를 관찰할 수 있었다. 산화몰리브덴이 첨가된 코팅의 마멸된 표면에 마찰, 마멸에 유리한 보호막의 형성이 광범위하게 일어남을 알 수 있었다. 이러한 보호막에 몰리브덴이 산화몰리브덴의 형태로 존재하는 것을 XPS 분석을 통하여 알 수 있었다. 보호막에 산화몰리브덴의 존재가 마찰계수를 감소시키는 것으로 생각된다.

• 한국가스학회지
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• 제7권1호
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• pp.19-23
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• 2003

최근 국내에서도 정량적 위험성 평가 기법을 위험시설물에 도입하여 위험도를 관리하면서 LPG 저장탱크에 대한 사고후 피해영향평가에 대한 연구는 다각적으로 이루어지고 있으나 BLEVE(Boiling Liquid Expanding Vapor Explosion, BLEVE)의 조건 및 메커니즘 규명에 대한 연구는 별로 이루어지고 있지 않다. 따라서, 본 고에서는 상대적으로 위험성이 큰 지상식 LPG 저장탱크의 BLEVE 가능성에 대해 외국의 Pilot 탱크 시험 결과 및 BLEVE 발생을 위한 소요입열량 계산값을 이용한 연역적 계산방법을 통해 BLEVE 조건 및 가능성을 정량화하여 규명코자 하였다. 또한, 산출된 탱크의 파열압력(burst pressure)과 충전량에 의해 보정된 액 온도를 사용해서 그려진 BLEVE map을 이용하여 BLEVE 조건에서 액위($\%$)가 BLEVE에 어떤 영향을 미칠 것인가를 규명하였다. 계산결과, 탱크 plate 온도가 $600^{\circ}C$이고, 탱크내부 액온도가 $53^{\circ}C$ 일 때 액충전량은 $43.68\%$ 이상일 경우에 BLEVE의 발생이 가능하다는 결과를 얻었다. 또한, 부천 대성에너지 LPG 충전소와 동일한 사양인 15톤 프로판 탱크를 모델로 하여 BLEVE가 발생하기 위한 외부 누출 및 외부화재 조건을 PHAST(Version 6.00) 및 EFFECTS(Version 2.1) 프로그램을 이용해 계산한 결과 액상 누출시 누출상당직경은 7.2mm, 이상 누출시 누출상당직경은 17.6mm 이상일 경우에 BLEVE가 발생 가능한 최소한의 풀화재 생성조건이 되었고, 풀화재의 크기는 최소 직경 3.3m, 높이 10.4m 이상의 풀화재가 전제되어야 한다는 결과를 얻을 수 있었다.

• 한국운동역학회지
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• 제15권3호
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• pp.143-152
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• 2005

The purpose of this study was to predict the failure or success of the Snatch-lifting trial as a consequence of the stand-up phase simulated in Kane's equation of motion that was effective for the dynamic analysis of multi-segment. This experiment was a case study in which one male athlete (age: 23yrs, height: 154.4cm, weight: 64.5kg) from K University was selected The system of a simulation included a multi-segment system that had one degree of freedom and one generalized coordinate for the shank segment angle. The reference frame was fixed by the Nonlinear Trans formation (NLT) method in order to set up a fixed Cartesian coordinate system in space. A weightlifter lifted a 90kg-barbell that was 75% of subject's maximum lifting capability (120kg). For this study, six cameras (Qualisys Proreflex MCU240s) and two force-plates (Kistler 9286AAs) were used for collecting data. The motion tracks of 11 land markers were attached on the major joints of the body and barbell. The sampling rates of cameras and force-plates were set up 100Hz and 1000Hz, respectively. Data were processed via the Qualisys Track manager (QTM) software. Landmark positions and force-plate amplitudes were simultaneously integrated by Qualisys system The coordinate data were filtered using a fourth-order Butterworth low pass filtering with an estimated optimum cut-off frequency of 9Hz calculated with Andrew & Yu's formula. The input data of the model were derived from experimental data processed in Matlab6.5 and the solution of a model made in Kane's method was solved in Matematica5.0. The conclusions were as follows; 1. The torque motor of the shank with 246Nm from this experiment could lift a maximum barbell weight (158.98kg) which was about 246 times as much as subject's body weight (64.5kg). 2. The torque motor with 166.5 Nm, simulated by angular displacement of the shank matched to the experimental result, could lift a maximum barbell weight (90kg) which was about 1.4 times as much as subject's body weight (64.5kg). 3. Comparing subject's maximum barbell weight (120kg) with a modeling maximum barbell weight (155.51kg) and with an experimental maximum barbell weight (90kg), the differences between these were about +35.7kg and -30kg. These results strongly suggest that if the maximum barbell weight is decided, coaches will be able to provide further knowledge and information to weightlifters for the performance improvement and then prevent injuries from training of weightlifters. It hopes to apply Kane's method to other sports skill as well as weightlifting to simulate its motion in the future study.

• 한국운동역학회지
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• 제24권2호
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• pp.173-180
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• 2014

The purpose of this study was to investigate the effect of combined exercise on injury risk factors of lower extremity during landing. Ten sports talented athletes participated in this study. Sports talented athletes participated in a combined exercise (sports talented exercise, coordination) for 16 weeks. A three-dimensional motion analysis was performed using eight infrared cameras (sampling rate of 100 Hz), one force plate, and electromyography system (sampling rate of 1000 Hz) during landing. Kinetic, and kinematics analysis including average impulsive force, angle of lower extremity, vertical stiffness, onset of muscle activation were calculated by Matlab2009a software. Paired t-test was performed at alpha=.05. The average impulsive force in landing phase was not statistically significant (t=-.748, p=.474). The hip joint angle was more decreased in post test compared to pre test (E1: t=2.682, p=.025, E2: t=5.609, p=.000, E3: t=2.538, p=.032). The knee joint (E1: t=-.343, p=.739, E2: t=1.319, p=.220, E3: t=.589, p=.570) and ankle joint (E1: t=.081, p=.937, E2: t=.784, p=.453, E3: t=.392, p=.704) angle were tended to decrease after combined exercise. The vertical stiffness was tended to decrease after combined exercise (t=1.972, p=.080). Onset of quadriceps femoris (t=.698, p=.503) and medial gastocnemius (t=1.858, p=.096) were tended to be faster than biceps femoris (t=-.333, p=.747) after combined exercise. Although thses findings were not statistically significant except on a hip joint angle, risk factors of lower extremity such as joint angle, vertical stiffness and onset of quadriceps femoris, medial gastrocnemius were positively changed after the combined exercise but an additional training for improved onset of biceps femoris would be required in the future.

• 천문학논총
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• 제36권3호
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• pp.79-95
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• 2021

This study aims to develop a restoration model of an armillary sphere of Tongcheon-ui (Pan-celestial Armillary Sphere) by referring to the records of Damheonseo (Hong Dae-Yong Anthology) and the artifact of an armillary sphere in the Korean Christian Museum of Soongsil University. Between 1760 and 1762, Hong, Dae-Yong (1731-1783) built Tongcheon-ui, with Na, Kyung-Jeok (1690-1762) designing the basic structure and Ann, Cheo-In (1710-1787) completing the assembly. The model in this study is a spherical body with a diameter of 510 mm. Tongcheon-ui operates the armillary sphere by transmitting the rotational power from the lantern clock. The armillary sphere is constructed in the fashion of a two-layer sphere: the outer one is Yukhab-ui that is fixed; and the inner one, Samsin-ui, is rotated around the polar axis. In the equatorial ring possessed by Samsin-ui, an ecliptic ring and a lunar-path ring are successively fixed and are tilted by 23.5° and 28.5° over the equatorial ring, respectively. A solar miniature attached to a 365-toothed inner gear on the ecliptic ring reproduces the annual motion of the Sun. A lunar miniature installed on a 114-toothed inner gear of the lunar-path ring can also replay the moon's orbital motion and phase change. By the set of 'a ratchet gear, a shaft and a spur gear' installed in the solstice-colure double-ring, the inner gears in the ecliptic ring and lunar-path ring can be rotated in the opposite direction to the rotation of Samsin-ui and then the solar and lunar miniatures can simulate their revolution over the period of a year and a month, respectively. In order to indicate the change of the moon phases, 27 pins were arranged in a uniform circle around the lunar-path ring, and the 29-toothed wheel is fixed under the solar miniature. At the center of the armillary sphere, an earth plate representing a world map is fixed horizontally. Tongcheon-ui is the armillary sphere clock developed by Confucian scholars in the late Joseon Dynasty, and the technical level at which astronomical clocks could be produced at the time is of a high standard.

• 한국운동역학회지
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• 제31권4호
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• pp.241-248
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• 2021

Objective: The purpose of this study was to investigate the difference in muscle strength, kinematics, and kinetics between injured and non-injured sides of the leg after Achilles Tendon Rupture surgery during walking and running. Method: The subjects (n=11; age = 30.63 ± 5.69 yrs; height = 172.00 ± 4.47 cm; mass = 77.00 ± 11.34 kg; time lapse from surgery = 29.81 ± 10.27 months) who experienced Achilles Tendon Rupture (ATR) surgery participated in this study. The walking and running trials were collected using infrared cameras (Oqus 300, Qualisys, Sweden, 100 Hz) on instrumented treadmill (Bertec, U.S.A., 1,000 Hz) and analyzed by using QTM (Qualisys Track Manager Ver. 2.15; Qualisys, U.S.A). The measured data were processed using Visual 3D (C-motion Inc., U.S.A.). The cutoff frequencies were set as 6 Hz and 12 Hz for walking and running kinematics respectively, while 100 Hz was used for force plate data. Results: In ATR group, muscle strength there were no difference between affected and unaffected sides (p> .05). In kinematic analysis, subjects showed greater ROM of knee joint flexion-extension in affected side compared to that of unaffected side during walking while smaller ROM of ankle dorsi-plantar and peak knee flexion were observed during running (p< .05). In kinetic analysis, subjects showed lower knee extension moment (running at 2.2 m/s) and positive ankle plantar-flexion power (running at 2.2 m/s, 3.3 m/s) in affected side compared to that of unaffected side (p< .05). This lower positive ankle joint power during a propulsive phase of running is related to slower ankle joint velocity in affected side of the subjects (p< .05). Conclusion: This study aimed to investigate the functional evaluation of the individuals after Achilles tendon rupture surgery through biomechanical analysis during walking and running trials. Based on the findings, greater reduction in dynamic joint function (i.e. lower positive ankle joint power) was found in the affected side of the leg compared to the unaffected side during running while there were no meaningful differences in ankle muscle strength and walking biomechanics. Therefore, before returning to daily life and sports activities, biomechanical analysis using more dynamic movements such as running and jumping trials followed by current clinical evaluations would be helpful in preventing Achilles tendon re-rupture or secondary injury.

• 산업식품공학
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• 제15권4호
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• pp.398-403
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• 2011

비열살균기술로서 저온플라즈마 활용 가능성을 탐색하고자 유전체장벽 방전 플라즈마(DBDP)생성장치를 제작하여 최적 플라즈마생성 조건을 도출하고 Staphyloocus aureus를 대상으로 살균성능을 조사하였다. DBDP생성장치는 전력공급장치, 변압기, 전극, 시료처리부 등 네 부분으로 구성하였다. 인가전압은 단상 200 V AC를 사용하고, 변압기를 통하여 10.0-50.0 kV로 변환하고 10.0-50.0 kHz의 주파수의 펄스 구형파를 유전체인 세라믹 블록 내에 장치한 전극에 투입함으로써 상압에서 플라즈마를 생성하였다. 주파수를 올림에 따라 높은 전류가 유입되었고, 이에 비례하여 전력소비량이 증가하였다. 전류세기 1.0-2.0 A, 주파수32.0-35.3 kHz 범위에서 균일하고 안정적인 플라즈마 발생이 이루어졌으며 시료를 투입하지 않은 상태에서의 최적 전극간격은 1.85 mm 이었다. 전극간격을 높임에 따라 소비전력이 증가하였으나 시료 처리에 적합한 전극간격은 2.65 mm였다. DBDP 처리에 의한 온도상승은 최대 20$^{\circ}C$에 불과하여 열에 의한 생물학적 효과는 무시할 수 있었으며 따라서 비열기술임이 확인되었다. Staphyloocus aureus를 대상으로 DBDP 처리할 경우 초기 5분 동안은 살균치가 직선적인 증가를 보이다가 이후 다소 완만해지는 경향을 보였으며 1.25 A에서 10분간 처리 시 살균치는 5.0을 상회하였다.