• Journal of Periodontal and Implant Science
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• 제37권4호
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• pp.671-679
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• 2007

Background: $TiUnite^{TM}$ is a highly crystalline and phosphate enriched titanium oxide surface which has a unique porous surface structure. This improved implant surface enhances bone response and reduces healing period. It also assures early stability of implant. These help to increase the success of implant. The aim of this study is to evaluate the survival rate of $TiUnite^{TM}$ surfaced single implant. Materials and methods: A retrospective analysis of 89 $TiUnite^{TM}$ surfaced implants replacing a single tooth was assessed according to their dental record. The age of the patients ranged from 17 to 82 years (mean age: $45.8{\pm}14.6)$. Data were recorded regarding the survival rate of these implants. Results: Fifty-two implants (57%) were placed in the maxilla, and 37 (43%) in the mandible. Over 75% were placed in the posterior area. Of the placed implants, 67% were the wide type. while 25% were the regular type and only 8% were of the narrow type. The single implants produced an overall clinical survival rate of 96.6% over the observation period (mean 17.9 months). Among 89 implants, only 2 implants were removed and one implant was submerged. Conclusion: According to these data, $TiUnite^{TM}$ surfaced implant in a single tooth restoration showed favorable survival rate although this study was done in a short term period.

• 한국균학회지
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• 제12권4호
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• pp.141-152
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• 1984

1. 검정곰팡이 (Aspergillus niger)를 실험재료로 하여 동조적으로 액침배양한 결과 포자의 발아로 부터 균사의 생장, 생식기관의 성숙 및 무성포자의 형성까지를 재현시킬 수 있었다. 2. 각 분화과정에서의 균체로 부터 고인산화뉴를레오티드를 추출하여 P.E.I. Cellulose TLC법으로 전개시켰다. 3. 포자형성 직전의 균체로 부터 얻은 추출물 중에 구아노신테트라포스페이트 $(GP_4)$가 존재함을 확인하였다. 4. 분화과정에 따른 균체로부터 추출한 유리아미노산의 총량은 포자형성 직전에 급격히 증가함을 알았다. 5. 정낭과 경자가 완성된 균체에 8-아자구아닌과 시클로헥시미드를 처리한 바 포자형성이 억제되었다. 6. 전낭과 경자가 완성된 균체에 이노신산과 구아닌산을 처리한 바 포자형성이 촉진되었다.

• 한국건축시공학회지
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• 제14권5호
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• pp.397-405
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• 2014

극한 염해환경에서 철근보강 지오폴리머 시험체의 외부전원법 전기방식 특성을 평가를 위하여 일련의 촉진실험을 실시하였다. 동시에 같은 조건의 보통 시멘트 콘크리트도 제조하여 비교 검토하였다. 환경조건은 침지대, 간만대, 그리고 크랙을 상정하였다. 지오폴리머는 밀실한 재료적 특성에 기인한 열화인자 침투 저항 증대에 의해 자연전위 뿐만 아니라 촉진 종료 후의 부식면적에서도 상당히 우수한 방식 성능이 있는 것으로 밝혀졌으며 향후 제작 양생 등의 문제를 개선함으로써 해양구조물로써의 활용이 다양해질 것으로 기대된다.

• 한국기계가공학회지
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• 제18권10호
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• pp.83-92
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• 2019

A pump is considered to be submersible when a motor and a pump are integrated and operate while submerged in water. Submersible pumps mainly function as rejection pumps to prevent foods in densely populated areas, as cold water circulation pumps in large power plants, as pumps to supply irrigation water, as drainage pumps to prevent flooding of agricultural lands, as water supply intake pumps, and as inflow pumps for sewage treatment. The flow in such turbomachines (submersible pumps) inevitably involves various eddy currents. Since it is almost impossible to accurately grasp the complex three-dimensional flow structure and characteristics of a rotating turbomachine through actual testing, three-dimensional numerical analysis using computational fluid dynamics techniques measuring the flow field, velocity, and the pressure can be accurately predicted. In this study, the shape of the impeller was developed to reduce vibration and noise. This was done by increasing the efficiency of the existing submersible pump and reducing turbulence. In order to evaluate the pump's efficiency and turbulence reduction, we tried to analyze the flow using ANSYS Fluent V15.0, a commercial finite element analysis program. The results show that the efficiency of the pump was improved by 4.24% and the Reynolds number was reduced by 15.6%. The performance of a developed pump with reduced turbulence, vibration, and noise was confirmed.

• 대한조선학회논문집
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• 제43권1호
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• pp.119-127
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• 2006

Recently as a result of excessive development. pollution of the coast and occurrence of a typhoon year after year, fishermen suffer heavy losses in fish farming which is the one of the most important earnings ways. For solution of these problems, we need to go out into the open sea from an inland sea. In this study we suggested new fish cage which makes up for the structural weakness of existing wooden fish cages. It can farm fishes in the open sea of high wave and current with no damages from a typhoon. We substituted TPU(Thermoplastic Polyurethane) air chamber for existing styrofoam flotage which was harmful to the environment and impermanent. We used PE(Polyethylene) pipes for the maintenance of formation and the prevention of buoyancy loss caused by a breakdown of flotage. PE b rackets were designed to combine PE pipes with TPU air-chamber flotage. It has good strength and light weight. As a result of modeling test. it is great in buoyancy, strength and flexibility against wave. Because it can control buoyancy arbitrarily, moreover, we expect that it will reduce damages of a red water by applying it as semi-submerged fish cages.

• 대한조선학회논문집
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• 제57권1호
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• pp.8-14
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• 2020

The implosion phenomena of pressure vessels operating in deep water under extremely high external pressure have been well known. The drastic energy release to ambient field in the form of pressure pulse is accompanied with catastrophic collapse of shell structure. Such a proximity shock wave could be a serious threat to the structural integrity of adjacent submerged body and several suspected accidents have been reported. In this study, basic research for the occurrence and development of shock wave due to implosion was carried out. The mechanism of pressure pulse generation and energy dissipation were investigated, and a simplified kinematic model to approximate the collapse modes of circular tubes which can be generated by external pressure and implosion was examined. Using the simplified kinematic model, the process of energy dissipation was formulated, and the magnitude of released pressure shock wave was estimated quantitatively. To investigate the validity of developed kinematic model and shock wave estimation process, the results from a nonlinear FE analysis code and collapse test carried out using pressure chamber were compared with the results from the developed kinematic model.

• Ocean Systems Engineering
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• 제11권1호
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• pp.17-42
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• 2021

Articulated loading platforms (ALPs) belongs to a class of offshore structures known as compliant. ALP motions have time periods falling in the wind excitation frequency range due to their compliant behaviour. This paper deals with the dynamic behavior of a double hinged ALP subjected to low-frequency wind forces with random waves. Nonlinear effects due to variable submergence, fluctuating buoyancy, variable added mass, and hydrodynamic forces are considered in the analysis. The random sea state is characterized by the Pierson-Moskowitz (P-M) spectrum. The wave forces on the submerged elements of the platform's shaft are calculated using Morison's Equation with Airy's linear wave theory ignoring diffraction effects. The fluctuating wind load has been estimated using Ochi and Shin wind velocity spectrum for offshore structures. The nonlinear dynamic equation of motion is solved in the time domain by the Wilson-θ method. The wind-structure interactions, along with the effect of various other parameters on the platform response, are investigated. The effect of offset of aerodynamic center (A.C.) with the center of gravity (C.G.) of platform superstructure has also been investigated. The outcome of the analyses indicates that low-frequency wind forces affect the response of ALP to a large extent, which otherwise is not enhanced in the presence of only waves. The mean wind modifies the mean position of the platform surge response to the positive side, causing an offset. Various power spectral densities (PSDs) under high and moderate sea states show that apart from the significant peak occurring at the two natural frequencies, other prominent peaks also appear at very low frequencies showing the influence of wind on the response.

• 한국산업융합학회 논문집
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• 제26권4_2호
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• pp.697-703
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• 2023

Intertidal zones, akin to tidal flats, are among the potential areas where underwater cultural heritage might be submerged. However, the shallow depths in these regions present challenges for conventional vessel-based survey methods. Moreover, during low tides, intertidal zones transform into tidal flats, limiting the efficiency of survey efforts due to restricted access and potential risks. As a result, proper underwater cultural heritage surveys encounter difficulties in these environments. In recent times, extensive research is underway to address these issues by investigating underwater cultural heritage surveys in intertidal zones, encompassing diverse fields, including equipment-based investigations. This study aimed to explore the feasibility of utilizing unmanned aerial vehicles (UAVs) to conduct intertidal cultural heritage surveys, employing aerial photography and 3D mapping to create detailed orthoimages and 3D models. The study focused on assessing the potential application of these techniques for cultural heritage surveying within intertidal zones. Notably, the survey conducted in Jindo's Naesan-ri demonstrated high-resolution capabilities, enabling the distinction of actual pottery fragments mixed within gravel fields. Similarly, in the survey of Jindo's Byeokpa-hang, it was found that a wooden pillar structure existed in a section about 200m long. The integration of various sensors, including LiDAR, with UAVs allows for diverse investigation possibilities, including bathymetric measurements, and is expected to facilitate the acquisition of varied datasets for further research and assessment.

• 건축역사연구
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• 제32권4호
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• pp.19-33
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• 2023

This study investigated the architectural expression of Taekpungdang(澤風堂, The Pond and Wind House) built by the Neo-Confucianist Taekdang Lee Sik(澤堂 李植, 1584~1647) from the perspective of the symbolic system of the Zhōuyì(『周易』, Classic of Changes). This study examined the historical context, personal history, and construction process of Taekpungdang at the time of its creation through his collection of writings, the Taekdanggip(澤堂集). The study also estimated the original form of Taekpungdang through field surveys and historical evidence. In addition, the architectural principles and architectural expressions inherent in the Taekpungdang were derived based on the symbolic system of "taekpungdaegwa"(澤風大過) which is Lee Sik's divination and one of the 64 trigrams in the Zhōuyì. Lee Sik, who was knowledgeable in the Zhōuyì, used divination to cope with the chaotic political situation and his own misfortunes. Accordingly, He determined the direction of his life and planned the surrounding environment, architectural structure, and form of Taekpungdang based on the rules and meanings of his divination system. He embodied the architectural space of Taekpungdang with the concept of time and space inherent in the divination of "daegwa",(大過, great exceeding). In addition, he expressed the principle of the generation of palgue,(八卦, the eight trigrams for divination) and the principle of the co-prosperity of ohaeng(五行, the five elements) through the composition of walls and windows of the house. The images of Taekpungdaegwae, which are dongyo(棟撓 wood submerged in the pond) and taekmyeolmok(澤滅木, shaking pillars), were manifested in the form of buildings. Therefore, Taekpungdang can be considered a remarkable example of a building designed through the thorough utilization of the Zhōuyì divination system.

• 농약과학회지
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• 제5권3호
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• pp.12-17
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• 2001

5-Benzofuryl-2-[1-(alkoxyimine) alkyl]-3-hydroxycyclohex-2-en-1-one 유도체중에서 2,3-dihydro-2,3,4,6,7-penta-methylbenzofuran-5-yl 그룹이 치완된 화합물(III)들의 벼(직파 및 3엽기)와 강피(Echinochloa crus-galli)에 대한 제초활성을 측정하고 alkoxy-치환체($OR_2$)가 변화함에 따른 구조와 제초활성과의 관계(SAR)를 정량적으로 검토한 결과, 직파벼와 강피 사이의 선택성 조건은 $R_1$=ethyl-이고 $R_2$-기는 비 대칭성의 적정값$(L/B_1)_{opt.}=3.96{\AA}$에 가까운 값을 갖는 치환체 이어야 할 것으로 판단되었다. 그리고 Free-Wilson 분석에 따르면 $R_2$-기는 $C_1{\sim}C_3$의 주로 불포화된 것들 중에서 특히, 3-chloro-2-propenyl기가 강피에 대한 제초활성을 가장 크게 나타내었다.