• 한국구조물진단유지관리공학회 논문집
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• 제24권3호
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• pp.9-17
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• 2020

이 연구의 목적은 프리캐스트 콘크리트 벽체와 H-pile로 구성된 벽체구조의 횡하중저항 성능을 평가하는 것이다. 이러한 형태의 구조는 옹벽 및 방음벽 기초 구조물로 사용된다. 실제 크기의 목업시험체를 설계하였으며, 실험체를 제작하였다. 대상 구조체의 설계횡하중은 54.6kN이다. 실제 현장에서 6.5m의 파일과 유사한 변형 프로파일을 갖는 실험체의 파일의 길이를 이론적으로 결정하였으며, 1.5m로 제작하였다. 실험중 벽체의 횡방향 변위가 파일의 변형률을 모니터링 하였으며, 균열의 발생을 육안 조사하였다. 실험으로부터 평가된 하중 및 변형 능력을 설계능력과 비교하였다. 실험결과는 설계하중을 저항하는데 충분한 성능을 보유하고 있음을 나타냈다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2004년도 춘계학술발표회
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• pp.738-745
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• 2004

There are a number of ways to reduce the ground vibrations, one of which is by installing underground walls. Model tests for ground vibration have been conducted in recent years, but limited attention has been paid to underground wall which can reduce high vibrations. Up to date, only barriers have been actually installed in dry sand because of many unknown factors subsisting on the behavior of the ground. The characteristics of vibration sources, ground conditions and wall barriers have not been well understood yet, therefore centrifugal modeling was adopted to examine all these characteristics. This paper describes a ball dropping system, which can generate a pulse wave propagation through soil mass, and the test results show the effectiveness of underground wall barrier in reducing mechanical vibration.

• 한국토양환경학회지
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• 제4권2호
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• pp.163-174
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• 1999

본 논문은 매립지의 침출수 유출로 오염된 지반 및 지하수의 효과적인 처리 방법 중의 하나인 연직 차수벽의 시공사례를 다루고 있다. 연직 차수벽의 설치 목적은 오염된 지하수의 이동을 경제적이고 효과적으로 차단하고, 차단후 차수벽 내부의 오염된 지하수를 회수하여 침출수 처리장에서 처리함으로써 추가적인 지반오염을 방지하며, 매립장의 잔여 이용 기간동안 매립장의 안전 운영의 기초를 확보하는 것이다. 현장조사의 단계에서 부터, 공법의 선정과 설계, 시공. 시공품질의 확인에 까지 일련의 과정을 보고하였다. 오염원과 오염의 원인 및 범위를 파악한 후, DMW공법과 HEC고화제를 이용하여 심층 혼합 차수층을 설치하였다. 균열이 심한 암반층의 차수를 위해서는 우레탄을 주입하여 차수층을 형성하였다. 조사기간 동안의 현장 모니터링 결과에 의하면, 토사와 암반층에 걸친 심층 혼합 차수층의 설치로 본 현장의 오염 처리는 현재를 기준으로 만족스러운 것으로 판단되었다.

• Wind and Structures
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• 제31권3호
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• pp.185-196
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• 2020

A method to reduce the wind pressure at the leading edge of a noise barrier was investigated by gradually lowering the height of a member added to the end of the noise barrier. The shape of the lowered height of the added member was defined by its length and slope, and the optimal variable was determined in wind tunnel testing via the boundary-layer wind profile. The goal of the optimal shape was to reduce the wind pressure at the leading edge of the noise barrier to the level suggested in the Eurocode and to maintain the base-bending moment of the added member at the same level as the noise-barrier section. Using parametric wind tunnel investigation, an added member with a slope of 1:2 that protruded 1.2 times the height of the noise barrier was proposed. This added member is expected to simplify, or at least minimize, the types of column members required to equidistantly support both added members and noise barriers, which should thereby improve the safety and construction convenience of noise-barrier structures.

• Nonlinear Functional Analysis and Applications
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• 제26권1호
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• pp.157-164
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• 2021

Recently we investigated a type of Hyers-Ulam stability of the Schrödinger equation with the symmetric parabolic wall potential that efficiently describes the quantum harmonic oscillations. In this paper we study a type of Hyers-Ulam stability of the Schrödinger equation when the potential barrier is a quartic wall in the solid crystal models.

• Journal of Ginseng Research
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• 제39권2호
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• pp.135-140
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• 2015

Background: A leaf cuticle has different structures and functions as a barrier to water loss and as protection from various environmental stressors. Methods: Leaves of Panax ginseng were examined by scanning electron microscopy and transmission electron microscopy to investigate the characteristics and development of the epicuticular structure. Results: Along the epidermal wall surface, the uniformly protuberant fine structure was on the adaxial surface of the cuticle. This epicuticular structure was highly wrinkled and radially extended to the marginal region of epidermal cells. The cuticle at the protuberant positions maintained the same thickness. The density of the wall matrix under the structures was also similar to that of the other wall region. By contrast, none of this structure was distributed on the abaxial surface, except in the region of the stoma. During the early developmental phase of the epicuticular structure, small vesicles appeared on wallecuticle interface in the peripheral wall of epidermal cells. Some electron-opaque vesicles adjacent to the cuticle were fused and formed the cuticle layer, whereas electron-translucent vesicles contacted each other and progressively increased in size within the epidermal wall. Conclusion: The outwardly projected cuticle and epidermal cell wall (i.e., an epicuticular wrinkle) acts as a major barrier to block out sunlight in ginseng leaves. The small vesicles in the peripheral region of epidermal cells may suppress the cuticle and parts of epidermal wall, push it upward, and consequently contribute to the formation of the epicuticular structure.

• Journal of Periodontal and Implant Science
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• 제28권2호
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• pp.219-237
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• 1998

Numerous bone graft materials have been used in Periodontics, in an attempt to reach the main goal of periodontal therapy, i.e. the regeneration of periodontal tissue lost due to destructive periodontal diseases. The present study investigates the effect of composite graft of DFDB and Calcium sulfate with and without Calcium sulfate barrier in Periodontal 1-wall intrabony defects in dogs. Following the initiation of general anesthesia by I.V. administration of 40mg/Kg of Pentobabital, second premolar was extracted and full thickness flap elevated. The crown portion of premolars was removed. Exposed root canals were sealed with Caviton and covered completely with flap. After the healing period of 8 weeks, the surgical sites were re-opened and 1-wall intrabony defects were created, and treated with flap operation alone(control group), with composit graft of 80% DFDB and 20% Calcium sulfate(Experimental group 1), with composite graft of DFDB and calcium sulfate with calcium sulfate membrane( Experimental group 2). Healing response was histologically observed after 8 weeks and the results were as follows : 1. New bone formation was 70 % in the control group, 93 % in the Experimental group I, 89 % in the Experimental group II. There was a no differences between Experimental groups. 2. New cementum formation was not significantly different between control and two Experimental groups. 3. The length of connective tissue adhesion was 30 % in the control, 7% in the Experimental group I and 11 % in the Experimental group II. 4. After 8weeks, calcium sulfate was completely resorbed, while DFDB particle remained. These results suggest that the use of composite graft of allogenic DFDB and Calcium sulfate with and without Calcium sulfate barrier in periodontal 1 wall intrabony defects have little effect on connective tissue adhesion, but has beneficial effect on new alveolar bone and new cementum formation, and prevent downgrowth of epithelium and connective tissue effectively.

• 한국음향학회지
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• 제35권3호
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• pp.223-233
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• 2016

공동주택단지 및 학교 및 근린시설의 경계방음벽으로 제시한 식생형 방음벽을 설계하고 소음감쇠성능실험을 실시하였다. 본 논문에서 제시한 식생형 방음벽은 일정한 형태의 유닛을 방음벽 형태의 구조물에 걸이식으로 적층하여 구성된 것으로서, 유닛내부에는 식재 및 토양을 포함하고 있다. 이 방음벽의 음향적인 장점은 토양 및 식재를 이용한 흡음뿐만 아니라 확산형상의 방음벽에서 표면 확산으로 인해 음에너지가 분산되어 소음을 저감할 수 있을 것으로 예상된다. 먼저 1/10 축소모형 실험을 통해 소음감쇠성능에 가장 적합한 방음벽 유닛의 크기를 조사하였으며, 설계된 도면에 따라 1/2축척의 식생형 방음벽을 실제높이 2 m, 길이 5 m로 제작하여 소음감쇠실험을 진행하였다. 식물을 담을 수 있는 총 1,137개의 식생블록은 약 $10{\times}10{\times}9cm$ 크기로 합성목재를 활용해 제작하였으며 이 블록들을 방음벽에 설치하여 자립형 구조를 가진 식생형 방음벽을 완성하였다. 연구결과, 평면형 방음벽보다 블록식 방음벽이 약 7 dB 더 높은 삽입손실을 나타냈으며, 식생블록의 크기는 삽입손실효과가 큰 $20{\times}20cm$의 크기가 적정한 것으로 나타났다.

• Journal of Periodontal and Implant Science
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• 제32권2호
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• pp.325-338
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• 2002

Bone graft using growth factors and guided tissue regeneration have been used for the regeneration of infrabony defects which caused by periodontal disease. Calcium sulfate which is one of the resorbable barrier materials used for guided tissue regeneration. Platelet rich plasma which is a easy method to obtain the growth factors had many common points but, platelet rich plasma was still studying. This study was the comparative study between bone graft using platelet rich plasma and guided tissue regeneration using calcium sulfate barrier material in clinical view. For the study, 28 sites(2 or 3 wall infrabony defects) were treated. 14 infrabony defects were received surgical implantation of BBP-calcium sulfate composite with a calcium sulfate barrier and the others received BBP mixed with platelet rich plasma. Clinical outcome was accessed 3 and 6 months of postsurgery. 1. There was no statistical difference between CS group and PRP group in pocket depth, gingival recession, clinical attachment level, and probing bone level at baseline. 2. There was statistically significant reduction in probing depth, clinical attachment level, and probing bone level at 3 and 6 months postsurgery(p<0.05). 3. In the probing depth and clincial attachment level PPR group had less improvement than CS group, but there was no statistically difference at 3 and 6 months postsurgery. 4. In the recession PPR group had less recession than CS group, but there was no statistically difference at 3 and 6 months postsurgery. 5. In the probing bone level PPR group had less improvement than CS group, but there was no statistically difference at 6 months postsurgery. In conclusion bone graft using platelet rich plasma and guided tissue regeneration using calcium sulfate barrier showed similar clinical improvement for the treatment of 2 or 3 wall infrabony defects.

• 한국지반공학회논문집
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• 제35권8호
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• pp.5-15
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• 2019

이 연구는 오염원 유출을 방지하기 위한 해상폐기물매립장 차수시스템에 요구되는 적절한 기준을 제안하기 위해 수행되었다. 차수시스템은 바닥층과 연직벽으로 구성된다. 바닥층은 불투수 점토층으로 연직벽은 이중벽체로 외곽벽체는 강관쉬트파일로 외력에 대한 저항을 담당하고 연직내부벽체가 차수를 담당하는 것으로 가정하였다. SEEP/W와 CTRAN/W 프로그램을 이용하여 침투-이류-분산 해석을 정상류 및 비정상류 조건에서 실시하였다. 해석결과, 정상류 조건에서 비정상류 조건 보다 오염원 이동이 크게 나타나 설계관점에서 차수기준은 정상류조건에서 산정된 값을 적용하는 것이 타당한 것으로 나타났다. 바닥층의 점토지반이 균질하고 연직차수시스템의 시공에 문제가 없다는 전제하에 정상류조건에서 오염원 이동의 차수에 요구되는 점토층 및 연직차수벽의 투수계수, 두께, 근입깊이 등이 제안되었다.