• 구강회복응용과학지
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• 제31권3호
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• pp.186-194
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• 2015

목적: 임플란트 위치와 길이가 하악 후방연장 가철성 국소의치(DERPD)와 연관된 임플란트의 응력 분포와 변위에 미치는 영향을 알아보는 것이다. 연구 재료 및 방법: #35, 36, 37이 소실된 시상절단면의 후방연장모형과 가철성 국소의치를 기본모형으로 사용했다. NX 9.0으로 7개의 모델을 디자인했다. 모델 A, B, C에서 각각 11, 6, 4 mm 길이의 임플란트가 #37 인공치 하방에 위치되었다. 모델 D, E, F에서 각각 11, 6, 4 mm의 임플란트가 #36 인공치 하방에 위치되었다. 모델 G는 임플란트가 없었다. 수직하중(250 N)을 #36의 중심와에 가했고, 유한요소 분석프로그램을 이용해 von Mises stress와 변위를 관찰했다. 결과: #37에 위치한 임플란트는 #36에 위치한 것과 비교시 주변골에 더 낮은 응력집중도를, #36에 위치한 임플란트는 #37에 위치한 것보다 더 적은 변위를 보였다. 결론: 임플란트 지지형 가철성 국소의치에서 후방부에 위치한 임플란트는 전방부에서보다 더 이점을 가지며, 길이가 더 긴 임플란트의 사용은 응력분산을 위해서 중요하다.

• Journal of Periodontal and Implant Science
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• 제35권2호
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• pp.449-460
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• 2005

Objectives Aim of this study was to evaluate the clinical use and the efficacy of Frialit-2 implant system. Experimental Methods Fifty nine patients received placement of Frilalit-2 implants(137 implants) in their maxillary anterior and posterior sites(40 and 97 implants). Intraoral & clinical examination, chart review and radiographs were taken from each patient. Results 1. The total implant survival rate was 92.7% after a mean follow-up period of 19.9 months. 2. The implant survival rate placed in anterior region was 97.5%. 3. The implant survival rate placed in posterior region was 90.7%. 4. The implant survival rate placed in atrophic posterior maxilla with advanced technique (GBR, Sinus elevation) was 87.2%. 5. The implant survival rate placed in type N(D4) bone was 82%, while 95.7% in type III (D3), and 100% in type II(D2) bone. 6. Most of the failed implants(7 of 10) were removed during the maintenance stage after prosthodontic treatment. Conclusion It was concluded that Frialit-2 implant could be used satisfactorily in the esthetic anterior region, but the use in the posterior region, especially with poor bone quality and quantity, further studies are needed.

• Journal of Periodontal and Implant Science
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• 제29권2호
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• pp.415-433
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• 1999

Implant stability is the key to long-term successful outcome for osseointegrated implants. To evaluate the initial healing response of bone around HA-coated implants without primary bone contact. 21 HA-coated thread type implants(STERI-OSS?) were placed in the femurs of 5 mongrel dogs, about 1-year old. Implants, 8 mm in length and 3.8mm(experimental 1group), 5.0mm(experimental 2group) and 6.0mm(control group) in diameter, were inserted after 3 holes of 6.0mm in diameter and 10mm in depth were prepared in the surgical sites each dog. Implants were supported by only nonresorbable membrane($Teflon^{(R)}$), in order to prevent the ingrowth of upper soft tissue into the gap between bone and implant, and to maintain each implant to be positioned in the center of the drilled hole. 9 implants with different diameters were inserted in 3 dogs for histologic observation, and 12 implants were inserted in 2 dogs for mobility test and removal torque test. Fluorescent dyes were injected for the observation of new bone formation in order of $Terramycin^{(R)}$, Arizarin $Red^{(R)}$, and $Calcein^{(R)}$ at an interval of 2 weeks. 3 dogs were sacrificed for histologic observation at 4, 8, and 12-week after placement. Light microscopy and confocal laser scanning microscopy were used to qualitatively characterize the bone around HA-coated implant. 2 dogs were sacrificed for mobility test($Periotest^{(R)}$, Simens AG, Bensheim, Germany) and removal torque test($Autograph^{(R)}$ AGS-1000D series, Japan) at 8 and 12-week after placement The results were as follows: 1. Histologic observation showed that osseointegration occurred to both control and experimental groups as time lapse, but delayed bone healing was revealed in 3.8mm group (experimental 1group), compared to contrtol group and 5.0mm group (experimental 2group). 2. The mobility test showed that the experimental groups had no distinguishable movement during experimental periods of 8 and 12-week, and there was no difference in mobility depending on the gap between bone and implant, and time lapse. 3. The removal torque forces were increased depended on the gaps decreasing between bone and implant, and time lapse. The results suggest that HA-coated implant without primary bone contact, based on guided bone regeneration could obtain its stability in all experimental groups as time lapse, but bone healing was delayed in experimental group of 3.8mm. And the results suggested that studies on correlationship between mobility test and removal torque test for implant stability would be necessary.

• 대한토목학회논문집
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• 제33권6호
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• pp.2509-2518
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• 2013

증강현실(Augmented Reality, AR) 기술은 현실 환경을 기반으로 컴퓨터에서 생성한 가상의 객체정보를 중첩해봄으로써 가상현실 상에서 느낄 수 없는 실감형 모델을 구현하는 기술이다. 본 연구에서는 토목공사 철근배근 작업에 증강현실 기술을 적용하는 방법론과 시스템 시제품을 구성하여 철근공사 작업의 증강현실 적용성을 검증하고 있다. 토목공사 현장의 여러 작업들 중에서 철근공사는 절차화된 매뉴얼방식보다는 숙련공의 경험적 방식에 의해 작업이 진행되는 대표적 공정이다. 이러한 공정에 증강현실을 적용하면 당초 계획도면과 비교하여 누락된 철근배근 및 상이한 배근 상태를 시각화하여 계측할 수 있으므로 시공성을 향상시킬 수 있다. 구축된 시스템은 3차원으로 모델링 된 철근객체를 실제 시공현장에 중첩하여 시각화함으로써 철근 조립공정들의 작업 이해도를 높이고, 검측단계에 활용함으로써 철근조립작업에서 발생할 수 있는 하자와 재작업으로 인한 비용증가를 억제할 수 있을 것이라 기대된다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2002년도 봄 학술발표회 논문집
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• pp.355-360
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• 2002

The purpose of this study was to remove the excessive air foaming which was produced in mixing the RSLMC(latex-modified concrete with rapid- setting cement) by choosing the best antifoam agent type and the optimized quantity for performance improved RSLMC. A series of RSLMM(latex-modified mortar with rapid-setting cement) experiments were carried out as the basic for RSLMC with the main experimental variables such as antifiamer types(A, B, C, D), antifoamer contents(0, 1, 2, 3%). Air content test and compressive, flexural tests were carried out to measure the improved properties of RSLMM and RSLMC. Chloride ion permeability test was carried out to estimate water permeability resistance. The results of RSLMM showed that the decrease of 50% air content was obtained by admixturing a antifoam agent by 1%. The compressive strength and flexural strength at 3 hours after RSLMC placement were 235kgf/cm$^2$ and 49kgf/cm$^2$, respectively, which exceeded the flexural strength criterion of 45kgf/cm$^2$ in order to open the RSLMC placed to traffic. The chloride permeability using A and C antifoamer at 28 days were below 100 coulombs, which was the permeability rating of negligible according to ASTM.

• 한국환경과학회지
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• 제15권9호
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• pp.907-912
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• 2006

The study is conducted to analyze the questioning styles in three middle school environmental textbooks in terms of frequency, type, and placement of questions. It is also to analyse and compare the kinds of scientific processes elicited by the questions in the topics of textbook. The instrument was the Textbook Questioning Strategies Assesment Instrument (TQSAI) which was developed the Cooperative Teacher Preparation Program, University of California. The mean number of questions per topic was 4.0 and the ratio of questions to sentences was 3.8%. The numbers of empirical and non-empirical questions were 52.5% and 47.5% for textbook D, 56.6% and 43.4% for textbook J, and 92.7% and 7.3% for textbook K, respectively. The open-hearted question was the highest in all types of questions for three middle school environmental textbooks. The explanatory question was the highest in all characteristics of questions. The types of various questions were distributed throughout textbooks including the green field, debate-discussion, examination, and so on.

• Journal of Electrical Engineering and Technology
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• 제10권3호
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• pp.804-811
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• 2015

The presence of responsive loads in the promising active distribution networks (ADNs) would definitely affect the power system problems such as distributed generations (DGs) studies. Hence, an optimal procedure is proposed herein which takes into account the simultaneous placement of DGs and smart meters (SMs) in ADNs. SMs are taken into consideration for the sake of successful implementing of demand response programs (DRPs) such as direct load control (DLC) with end-side consumers. Seeking to power loss minimization, the optimization procedure is tackled with genetic algorithm (GA) and tested thoroughly on 69-bus distribution test system. Different scenarios including variations in the number of DG units, adaptive power factor (APF) mode for DGs to support reactive power, and individual or simultaneous placing of DGs and SMs have been established and interrogated in depth. The obtained results certify the considerable effect of DRPs and APF mode in determining the optimal size and site of DGs to be connected in ADN resulting to the lowest value of power losses as well.

• Computers and Concrete
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• 제26권5호
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• pp.429-438
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• 2020

To shorten the construction times of nuclear facility structures, three high-strength concrete mixtures were developed with specific consideration given to their curing temperatures, their economic efficiency, and the practicality of their quality control. This study was conducted to examine the temperature rise profiles of these three concrete mixtures and the potential for early-age thermal cracking in the primary containment vessel of a nuclear reactor with a wall thickness of 1200 mm. The one-layer placement height of the concrete for the primary containment vessel was increased from the conventional 3 m to 3.5 m. A nonlinear finite element analysis (FEA) was conducted using the thermal properties of concrete determined from the isothermal hydration and adiabatic hydration tests, and tuned through comparisons made with temperature rise profiles obtained for 1200-mm-thick mock-up wall specimens cured at temperatures of 5, 20, and 35℃. The hydration heat performance of the three concrete mixtures and their potential to produce thermal cracking in nuclear facilities indicate that the mixtures have considerable potential for practical application to the primary containment vessel of a nuclear reactor at various curing temperatures, fulfilling the minimum requirements of the ACI 301 and minimizing the likelihood of the occurrence of thermal cracks.

• 한국자기학회지
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• 제8권5호
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• pp.308-316
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• 1998

본 연구에서는 부상에 필요한 소비전력을 최소화 할 수 있고, 부상력과 추진력을 동시에 얻을 수 있는 제어-영구자석형 선형동기전동기에 대하여 횡변위가 기기의 추진력, 부상력, 안내력에 미치는 영향을 3차원 유한요소해석을 통하여 검토하였다. 횡변위에 대한 공극자속밀도의 분포특성과 힘 특성의 변화에 대하여 검토하고 횡변위 및 공극 길이의 변화가 기기의 특성에 미치는 영향에 대하여 해석과 실험을 통하여 분석하였다. 본 연구결과 횡변위 및 공극의 변화가 제어-영구자석형 선형동기 전동기의 특성에 미치는 영향을 정량적으로 알 수 있었다.

• 한국의류학회지
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• 제42권6호
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• pp.1002-1015
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• 2018

In this study, we analyzed the results of virtual clothing simulation according to the difference in the lateral neck point as well as the front and back shoulder inclination angles of the bodice foundation. Lim's (2016) (S) and Lee's (1999) method (L) were selected as the different setting for the lateral neck point. S1, S2, L1 and L2 were developed by changing the shoulder inclination angles. The SND and LND were developed by removing the darts in the S and L, respectively; in addition, the SND1, SND2, LND1, and LND2 were developed with different shoulder inclination angles. The results of S and L were similar with only slight differences observed in the armhole shape. However, the results of SND and LND were very different. The patterns of the S series were similar to each other, but the patterns of the L series were different. In addition, the patterns of the SND and LND series could not find a similar trend.