• 대한치과의사협회지
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• 제22권7호통권182호
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• pp.607-620
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• 1984

Mandibular Kinesiograph (MKG-5R)으로부터 얻어지는 자료의 유효성에 관한 연구를 위하여 비철, 비자석성의 기구를 이용해서 3cm×4cm×5cm의 4차원적 입체공간내에서 수행하였다. Kinesiograph로 부터의 직접 얻어지는 자료(관찰치)와 실제 움직인 거리(실제치)간의 관계를 먼저 보기위해 Scatter plot과 Correlation이 연구됐다. 그러나 최종의 목표는 어떤 형태의 공식을 만들어 이것으로 Kinesiograph관찰치를 이용, 실제치를 알도록 하는 것이었으므로 관찰치의 통계학적 회귀분석이 수행되었다. 통계분석의 결과는 Kinesiograph 관찰치와 실제치 간의 강한 상관관계를 보였다. 그러나 높은 상관계수가 반드시 얻어진 선형모형의 완벽한 예측성을 의미하는 것은 아니다. 이 연구로부터 얻어진 선형모형이 실제치를 모두 완벽하게 예측할수는 없었다. 그 이유로서는 종속변수(실제치)의 불연속성과 관찰치(비종속변수) 상호간의 독랩성 때문이다. 결론적으로 Kinesiograph가 어떤 형태로든 적절한 방법에 의해 수정이 있지 않으면 그 계통자체내에 내재하는 비선형적 특성 때문에 그 이용이 하악운동의 제한된 범위내에만 적용될 수 있다.

• 대한치과의사협회지
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• 제22권7호통권182호
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• pp.621-633
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• 1984

Kinesiograph로부터 얻어지는 자료의 선형범위를 확장하고자 하는 연구가 비철, 비자석성의 기구를 사용하여 수행되었다. 자석을 5mm의 일정한 간격으로 자석감지장치가 달린 구조물에 팽팽하게 세평면(frontal, horizontal, sogittal plam)을 통해 3cm×4cm×5cm의 입체공간내에서 693개의 움직여서 만들어지는 자료점으로 항렬 (matrix)을 얻었다. 각각의 자료점에 있어서 Kinesiograph로부터 얻어진 관찰된 값과 움직인 실제값이 상관지어졌다. 따라서 관찰된 값의 세 상관계수를 알게되면 실제값인 세 계수를 얻을수 있게 됐다. 이 업무를 수행하기 위해서 컴퓨터 프로그램이 Fortran을 이용해서 특별히 쓰여졌다. 각 자료점이 5mm 서로 떨어져 있으므로 연구된 입체공간에는 각각 8개의 자료점을 가진 480개의 입방체가 존재한다. 따라서 각각 자료점간에 더 작은 간극을 마련할 수 있다면 보다 더 정밀한 계측이 가능 할 것이다. 결론으로 컴퓨터의 도움으로 기능적 하악운동의 전체범위에 걸친 절대계측들 가능케 하는 이론적 모형이 제시되었다.

• 대한치과기공학회지
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• 제35권2호
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• pp.127-136
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• 2013

Purpose: In order to find out the impact of changes in polymerization conditions of orthodontic acrylic resin on maximum load. Methods: While maintaining mixing ratio 3:1 of polymer and monomer in spray-on way in the production condition of polymerization temperature $25^{\circ}C$ or $37^{\circ}C$ for 10 minutes or 30 minutes of polymerization time by pressure $3kfg/cm^2$ or $6kfg/cm^2$ in the lab maintaining $25^{\circ}C$ of room temperature, the change in maximum load rise rate was tested by producing 5 acrylic resin specimens for orthodontics per group to meet the standards of $25mm{\times}2mm{\times}2mm$ and using INSTRON with the 3rd bar 2mm in diameter and parallel support bending device of $15{\pm}0.1mm$ as test equipment showing 30.00mm/min of crosshead speed, $50{\pm}16$ N/min of load ratio in the laboratory of $24^{\circ}C$ room temperature and as a result, the following results were obtained. Results: 1. When increasing pressure from $3kfg/cm^2$ to $6kfg/cm^2$, maximum load was lowered by -4.285%. 2. When increasing polymerization time from 10 minutes to 30 minutes, maximum load rose by 3.848%. 3. When increasing polymerization temperature from $27^{\circ}C$ to $37^{\circ}C$, maximum load rose by 5.854%. Conclusion: Considering the above test results that polymerization time and polymerization temperature when polymerizing acrylic resin for orthodontics according to changes in working conditions had an impact on the rate of rise of maximum load values but the rate of rise was lowered when increasing pressure from $3kfg/cm^2$ to $6kfg/cm^2$, we came to a conclusion that high pressure more than necessary does not affect the rate of rise of maximum load.

• 복식문화연구
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• 제18권1호
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• pp.64-79
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• 2010

The digital era in the 21st century is globalized and is collapsed boundary among countries, thereby being able to be said to be characterized most largely by proceeding with being a form like a federation and EU. A change into digital era brought about a change in all the aspects of human behavior and culture, not a change simply in temporal significance and technological significance. In recent days, all the services came to be possibly used the integrated device with the same network owing to innovation of communication technology, which is represented by digital, network, and internet. Now, the broadcasting industry, computer industry, and communication industry are exceeding the peculiar sphere by being mutually merged. Each of industrial sector centering on internet is showing the phenomenon of being united. The hybrid trend, which was formed by phenomenon in the complex digital media society, tended to be indicated in fashion and makeup design. As the digital media era was generated, the hybrid trend induced a change into society in open and horizontal idea. It came to be known that there is independent trend in each field even while organically working in the middle of the whole frame that fashion and makeup express a human being's external beauty. This implies that makeup is not what is always influenced by fashion as an accessory in fashion and a supplementary role, but what can show its contrary phenomenon. This study examined characteristics, which are shown in fashion and makeup due to hybrid influence with greeting the digital media era. This study was carried out in order to be conducive to objective data available for giving help to the future direction and marketing data in product of the relevant businesses, through the results of this study.

• Restorative Dentistry and Endodontics
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• 제40권4호
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• pp.262-269
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• 2015

Objectives: The aim of this study was to evaluate the mechanical and physical properties of a newly developed fiber reinforced dental composite. Materials and Methods: Fiber reinforced composite EverX Posterior (EXP, GC EUROPE), and other commercially available bulk fill composites, including Filtek Bulk Fill (FB, 3M ESPE), SonicFill (SF, Kerr Corp.), SureFil (SDR, Dentsply), Venus Bulk Fill (VB, HerausKultzer), Tetric evoceram bulk fill (TECB, Ivoclar Vivadent), and Xtra Base (XB, Voco) were characterized. Composite samples light-cured with a LED device were evaluated in terms of flexural strength, flexural modulus (ISO 4049, n = 6), fracture toughness (n = 6), and Vickers hardness (0, 2, and 4 mm in depth at 24 hr, n = 5). The EXP samples and the fracture surface were observed under a scanning electron microscopy. Data were statistically analyzed using one-way ANOVA and unpaired t-test. Results: EXP, FB, and VB had significantly higher fracture toughness value compared to all the other bulk composite types. SF, EXP, and XB were not statistically different, and had significantly higher flexural strength values compared to other tested composite materials. EXP had the highest flexural modulus, VB had the lowest values. Vickers hardness values revealed SF, EXP, TECB, and XB were not statistically different, and had significantly higher values compared to other tested composite materials. SEM observations show well dispersed fibers working as a reinforcing phase. Conclusions: The addition of fibers to methacrylate-based matrix results in composites with either comparable or superior mechanical properties compared to the other bulk fill materials tested.

• Journal of Astronomy and Space Sciences
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• 제29권2호
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• pp.221-232
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• 2012

We analyzed the manufacturing procedure, specifications, repair history, and details of celestial movements of the water-hammering type $Honsang$ (celestial globe). Results from our study on the remaining $Honsangs$ in China and Japan and on the reconstruction models in Korea were applied to our conceptual design of the water-hammering type $Honsang$. A $Honui$ (armillary sphere) and $Honsang$ using the water-hammering method were manufactured in $Joseon$ in 1435 (the 17th year of King $Sejong$). $Jang$ $Yeong-Sil$ developed the $Honsang$ system based on the water-operation method of $Shui$ $y{\ddot{u}}n$ $i$ $hsiang$ $t'ai$ in China. Water-operation means driving water wheels using a water flow. The most important factor in this type of operation is the precision of the water clock and the control of the water wheel movement. The water-hammering type $Honsang$ in $Joseon$ probably adopted the $Cheonhyeong$ (天衡; oriental escapement device) system of $Shui$ $y{\ddot{u}}n$ $i$ $hsiang$ $t'ai$ in China and the overflow mechanism of $Jagyeongnu$ (striking clepsydra) in $Joseon$, etc. In addition to the $Cheonryun$ system, more gear instruments were needed to stage the rotation of the $Honsang$ globe and the sun's movement. In this study, the water-hammering mechanism is analyzed in the structure of a water clock, a water wheel, the $Cheonhyeong$ system, and the $Giryun$ system, as an organically working operation mechanism. We expect that this study will serve as an essential basis for studies on $Heumgyeonggaknu$, the water-operating astronomical clock, and other astronomical clocks in the middle and latter parts of the $Joseon$ dynasty.

• Restorative Dentistry and Endodontics
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• 제41권4호
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• pp.304-309
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• 2016

Objectives: The purpose of this study was to compare the maximum screw-in forces generated during the movement of various Nickel-Titanium (NiTi) file systems. Materials and Methods: Forty simulated canals in resin blocks were randomly divided into 4 groups for the following instruments: Mtwo size 25/0.07 (MTW, VDW GmbH), Reciproc R25 (RPR, VDW GmbH), ProTaper Universal F2 (PTU, Dentsply Maillefer), and ProTaper Next X2 (PTN, Dentsply Maillefer, n = 10). All the artificial canals were prepared to obtain a standardized lumen by using ProTaper Universal F1. Screw-in forces were measured using a custom-made experimental device (AEndoS-k, DMJ system) during instrumentation with each NiTi file system using the designated movement. The rotation speed was set at 350 rpm with an automatic 4 mm pecking motion at a speed of 1 mm/sec. The pecking depth was increased by 1 mm for each pecking motion until the file reach the working length. Forces were recorded during file movement, and the maximum force was extracted from the data. Maximum screw-in forces were analyzed by one-way ANOVA and Tukey's post hoc comparison at a significance level of 95%. Results: Reciproc and ProTaper Universal files generated the highest maximum screw-in forces among all the instruments while M-two and ProTaper Next showed the lowest (p < 0.05). Conclusions: Geometrical differences rather than shaping motion and alloys may affect the screw-in force during canal instrumentation. To reduce screw-in forces, the use of NiTi files with smaller cross-sectional area for higher flexibility is recommended.

• 디지털융복합연구
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• 제14권12호
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• pp.369-375
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• 2016

본 연구는 환자의 경추보호대 착용 여부에 따른 후두마스크기도기(LMA)와 I-gel, Streamlined Liner of the Pharynx Airway(SLIPA) 등 3가지 성문위기구의 삽관 용이성을 비교하기 위해 시행되었다. 응급의료현장에서 활동 중인 119 구급대원 39명에게 3가지 성문위기구에 대한 짧은 교육을 시행한 후 삽관시간과 삽관시도횟수를 측정하였다. 삽관시간은 중립위와 경추보호대 착용 시 모두 I-gel($10.5{\pm}2.2$, $11.4{\pm}5.7$), SLIPA($12.3 {\pm}5.1$, $12.0{\pm}6.8$), LMA($17.2{\pm}3.2$, $18.5{\pm}5.5$) 순으로 빨랐다 (p<0.05). 각 기도기별 중립위와 경추보호대 착용 시 삽관시간의 차이는 없었다. 결론적으로 I-gel과 SLIPA가 LMA보다 중립위와 경추보호대 착용 시 모두에서 삽관시간이 더 빠른 결과를 보였다.

• Journal of Periodontal and Implant Science
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• 제39권4호
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• pp.385-390
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• 2009

Purpose: In this study we evaluated the morphologic aspects of defects created by a piezoelectric ultrasonic scaler with scaler tip on casting gold alloy using scanning electron microscope (SEM) images and defect surface profiles. Methods: 54 blocks of type III casting gold alloy (Firmilay, Jellenko Inc, CA, USA) were scaled by a piezoelectric ultrasonic scaler (P-MAX, Satelec, France) with scaler tip (No. 1 tip) on a sledge device. 2-dimensional profiles of defects on all samples were investigated by a surface profilometer (a-Step 500, KLA-Tencor, CA, USA). The selected working parameters were lateral force (0.5 N, 1.0 N, 2.0 N), mode (P mode, S mode), and power setting (2, 4, 8). SEM images were obtained. Defect surface profiles were made on Microsoft Excel program using data obtained by a surface profilometer. Results: Among P mode samples, there were similarities on defect surface profiles and SEM images regardless of lateral force. The defects created in P mode were narrow and shallow although the depth and the width increased as power setting changed low (2) to high (8). In P mode samples, the defect depth was the greatest when lateral force of 0.5 N was applied. However all the depths were smaller than 1 m. SEM images of Lateral force of 0.5 N, S mode, power setting 2 and 4 were similar to that of P mode, but the other SEM images of S mode showed discernible changes. Defect depth of S mode samples was the greatest when lateral force of 1.0 N was applied. Conclusions: Within the limitations of this study, it can be concoluded that removing capability of piezoelectric scaler with scaler tip becomes maximized as power level becomes higher but the capability is restricted when excessive lateral force is applied on scaler tip.

• 한국전기전자재료학회논문지
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• 제29권12호
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• pp.803-808
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• 2016

In this work, one dimension $In_2O_3$ nanostructures as detecting materials for indoor toxic gases were synthesized by an electrospinning process. The morphology of electrospun $In_2O_3$ nanofibers was controlled by electrolyte composition, applied voltage and working distance between a nozzle and a substrate. The synthesized $In_2O_3$ nanofibers-based paste with/without carbon black additives was prepared for the integration on a sensor device. The integration of $In_2O_3$ sensing materials was conducted by a hand-printing of the paste into the interdigit Au electrodes patterned on Si wafer. Gas sensing properties on CO and HCHO gases were characterized at $300^{\circ}C$. The evaluated sensing properties such as sensitivity, response time and recovery time were improved in $In_2O_3$ nanofiber pastes with carbon black, compared to the paste without carbon black.