• 대한치과보철학회지
• /
• 제58권2호
• /
• pp.153-160
• /
• 2020

증령에 따라 진행되는 치아의 마모는 자연스러운 현상이지만 생리적인 범위를 초과하여 나타나는 병적 마모는 기능 및 심미 문제를 야기하게 된다. 특히, 구치부 지지가 상실되면 전치부의 병적 마모로 인해 수직 고경의 감소와 교합평면의 부조화가 일어날 수 있다. 이러한 문제를 해결하려면 중심위를 고려한 적절한 수직 고경 설정이 필요하다. 본 증례의 환자는 상악 구치부 상실에 의한 하악 전치부의 심한 마모를 보이는 71세 남환으로 보철 수복 공간을 위해 수직 고경을 거상하여 전악 수복을 시행하였다. 8개월간의 평가 결과 안정적인 교합을 확인하였고 기능적, 심미적으로 만족할만한 결과를 보였기에 이를 보고하고자 한다.

• 대한조선학회논문집
• /
• 제43권3호
• /
• pp.384-391
• /
• 2006

RCS effects of long-crested wave surfaces to marine targets are numerically analyzed using a 4-path model and a direct analysis method, developed based on physical optics and a combined method of physical optics/geometric optics, respectively. Reflectivity of long-crested wave surfaces is described with 'Fresnel reflection coefficients' The MPM(modified Pierson-Moskowitz) ocean spectrum is adopted to simulate long-crested waves in the direct analysis method. A numerical analysis of a benchmark model assures the validity of both methods. The direct analysis method is applied to the RCS calculation of electromagnetically large marine targets, which are vertically oriented or slanted to the long crested wave surfaces randomly generated with various significant wave heights. The long-crested wave surface much highly increases the RCS of the marine target, but those effects are decreased as the significant wave height grows up. At low elevation angle, the vertical model has entirely high RCS comparing slanted model, and the RCS of vertical flat plate is the highest on the calm sea surface, while those of slanted flat plates are the lowest on the calm sea surface. The RCS of marine targets on continuously-varying sea surface is more coherent at lower elevation angles, as well.

• 대한원격탐사학회지
• /
• 제21권1호
• /
• pp.73-81
• /
• 2005

We construct improved geocentric digital elevation model (DEM), estimate tidal dynamics and ice stream velocity over Sulzberger Ice Shelf, West Antarctica employing differential interferograms from 12 ERS tandem mission Synthetic Aperture Radar (SAR) images acquired in austral fall of 1996. Ice, Cloud, and land Elevation Satellite (ICESat) laser altimetry profiles acquired in the same season as the SAR scenes in 2004 are used as ground control points (GCPs) for Interferometric SAR (InSAR) DEM generation. 20 additional ICESat profiles acquired in 2003-2004 are then used to assess the accuracy of the DEM. The vertical accuracy of the OEM is estimated by comparing elevations with laser altimetry data from ICESat. The mean height difference between all ICESat data and DEM is -0.57m with a standard deviation of 5.88m. We demonstrate that ICESat elevations can be successfully used as GCPs to improve the accuracy of an InSAR derived DEM. In addition, the magnitude and the direction of tidal changes estimated from interferogram are compared with those predicted tidal differences from four ocean tide models. Tidal deformation measured in InSAR is -16.7cm and it agrees well within 3cm with predicted ones from tide models. Lastly, ice surface velocity is estimated by combining speckle matching technique and InSAR line-of-sight measurement. This study shows that the maximum speed and mean speed are 509 m/yr and 131 m/yr, respectively. Our results can be useful for the mass balance study in this area and sea level change.

• 대한원격탐사학회지
• /
• 제22권6호
• /
• pp.533-542
• /
• 2006

Lidar는 정확도 높은 고밀도의 점 자료를 제공함으로써 지형공간에 대한 3차원 정보를 제공한다. 특히, 산림과 같은 식생 지역에서는 레이저 신호가 투과되어 지면에서 반사되는 자료가 기록되므로 산림이 밀집하여 존재하는 공간에 대한 수치고도모델 제작에 용이하다. 이 연구에서는 우리 나라 중부지역의 산림에서 획득한 Lidar자료의 수직적 분포 특성을 살펴보고자 하며, 산림자원정보를 추출 및 수치고도자료(DEM)를 획득하기 위한 필수 과정인 지면점들을 분리하는 방법을 제안하고자 한다. Lidar 자료의 수직적인 분포는 산림을 구성하는 수종, 밀도 및 수관의 형태 등에 따라 영향을 많이 받으며, 이러한 산림에서 나타나는 Lidar 자료의 특성을 이용하여 제안된 지면점 분리 방법은 초기 수신신호(First return: FR) 및 말기 수신신호(Last Return: LR)를 함께 이용함으로써 일반적으로 지면점을 분리하는데 요구되는 임계치를 고려하지 않아도 된다는 효율성을 가진다. 제시된 방법으로 분리된 지면점을 이용하여 수치고도모델을 제작하였으며, 이를 기반으로 산림의 중요한 정보가 되는 수고, 수관울폐도 등의 임목의 생물리학적 인자를 보다 정확하게 추출할 수 있다.

• 한국환경과학회지
• /
• 제30권12호
• /
• pp.1067-1079
• /
• 2021

The coastal water is a space where salmon (Oncorhynchus keta), critical energy-conveying mediator, stay to adapt to different environments while traveling between ocean and river ecosystems for spawning and growth. The mid-eastern coast of Korea (MECW) is the southern limit of salmon distributed in the North Pacific Ocean. Understanding the distribution and migration characteristics of salmon in the MECW is important for the prediction of changes in the amount and distribution of salmon related to changes in the future marine environment. We analyzed the relationship between the salmon migratory timing ascending the Wangpi river and change in vertical seawater temperature and tidal elevation. Overall results highlight that (1) Salmon began to ascend the river when the sea surface water temperature (SST) decreased below 20℃; (2) The number of salmon ascending the river increased when the temperature difference between the upper and lower layers decreased, but decreased when the temperature difference was higher than 5℃; (3) The number of salmon ascending the river peaked, when the SST was 18℃-19℃ and sea levels rose at high tide. This study provide important insight into predicting changes in the ecosystem energy circulation through climate change at its southern distribution limit.

• 대한조선학회논문집
• /
• 제60권2호
• /
• pp.120-134
• /
• 2023

In this study, hydrodynamic characteristics of dam break flow were investigated by a series of experiments. The experiments were performed in a 2-D rectangular flume with obtaining instantaneous images of dam break flow to capture the free surface elevation, and pressure distributions on vertical wall and bottom of the flume. The initial water depth of the dam break flow was changed into 3 different heights, and the gate opening speed was changed during the experiments to study the effect of the gate speed in the dam break flow. Generation of dam break phenomena could be classified into three stages, i.e., very initial, relatively stable, and wall impact stages. The wall impact stage could be separated into 4 generation phases of wall impinge, run-up, overturning, and touchdown phases based on the deformation of the free surface. The free surface elevation were investigated with various initial water depth and compared with the analytic solutions by Ritter (1892). The pressures acting on the vertical wall and bottom were provided for the whole period of dam break flow varying the initial water depth and gate open speed. The measurement results of the dam break flow was compared with the hydrodynamic characteristics of green water phenomena, and it showed that the dam break flow could overestimate the green water loading based on the estimation suggested by Buchner (2002).

• 한국해안해양공학회지
• /
• 제4권4호
• /
• pp.208-218
• /
• 1992

1차원 폐쇄형 수노에서 바람에 의해 발생되는 흐름에 대해 수면구배와 유속의 수직구조를 제시하는 해석해를 정상상태 하에서 유도하였다. 해석해는 저면의 경계조건으로 저면마찰응력 $ au$$_{b}$를 부여하는 가정하에 유도되었으며, 연직 운동양 확산계수 $ extsc{k}$$_{M}$이 수심에 무관한 상수, 수심의 1차함수 및 2차함수일 경우를 포함하며, 저면류속이 no-slip이라는 가정과 저면마찰응력 $\tau$$_{b}$의 매개화에 따른 관계를 제시하고 있다. 모드 분리된, $\sigma$좌표를 채택한 (x-$\sigma$) 수치모형 결과와 유도된 해석해를 비교ㆍ검토하였다. 비교된 경우는 $textsc{k}$$_{M}$이 상수, 수심의 1차 및 2차함수인 경우로써, $textsc{k}$$_{M}$이 상수일 경우는 균일 수심, 완만한 수심경사 및 비교적 급격한 수심경사를 갖는 경우에 대해 수면구배와 유속구조를 검토 하였다. $textsc{k}$$_{M}$이 수심의 1차 및 2차함수인 경우에는 $\tau$$_{b}$의 변화에 대한 유원구조를 비교ㆍ분석하였다. 비교ㆍ분석 결과 유연구조는 $textsc{k}$$_{M}$ 값 뿐만 아니라 $textsc{k}$$_{M}$의 형태에 의해서도 변하며, $\tau$$_{b}$의 간에 의해서도 변하는 것을 보이고 있으며, 계산결과는 전반적으로 해자해와 일치함을 보였다.치함을 보였다.보였다.치함을 보였다.

• Pediatric Gastroenterology, Hepatology & Nutrition
• /
• 제2권1호
• /
• pp.109-115
• /
• 1999

Hepatitis C virus (HCV) has been identified as an important cause of posttransfusion hepatitis, but vertical transmission of chronic infected HCV RNA positive mothers has been documented in some cases. The reports of the risk of perinatal infection have been widely varied in the literature. The authors experienced one case of vertical transmission of HCV in an infant of a mother who had hepatitis C during pregnancy. At admission, HCV RNA (+), Ig G anti HCV (+) and Ig M anti HCV (+) were found in the mother. Also at admission, HCV RNA (+), Ig G anti HCV (+), Ig M anti HCV (+), elevation of liver aminotransferase level and hepatosplenomegaly on ultrasonography were found in the baby on day 31. HCV RNA (-), Ig M anti HCV (-) and normal of liver aminotransferase level were noted on day 250 in the serum of the infant. We used reverse transcriptase polymerase chain reaction (RT-PCR) technique to find a very small amount of HCV RNA in the serum. All the findings suggest vertical transmission of HCV RNA from mother to infant during 3rd trimester of pregnancy.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• 제34권3호
• /
• pp.341-349
• /
• 2008

Purpose: The purpose of this study was to evaluate the $Osstem^{(R)}$ implants (US II/SS II implants) through the retrospective study for the clinical success rate during the installation of the $Osstem^{(R)}$ implants (US II/SS II implants) by using of the procedures of maxillary sinus floor elevation. Materials and methods: The current study was researched in the 6 medical institutions: Chonnam National University, Chosun University, Pusan DaeDong Hospital, Bundang Seoul National University Hospital, Ap-Seon Clinic, and All Clinic. Based on the total number of 116 patients whose treatment was the installation of the US II/SS II implants with the procedures of the maxillary sinus floor elevation, they were conferred on the dental records of the patients under the joint consultation of the 6 medical institutions. On the dental recording charts, there were included in as the following; the name of the institutions, gender, age, with or without smoking or drinking, with or without the generalized diseases, the height of the alveolar bone on the operational sites, elapsed edentulous state period, the state of the opposed or adjacent teeth, the methods of the maxillary sinus floor elevation, secondary time period for surgery, the lengths, types, and diameters of implants, with or without bone transplantation or the types of bone, postoperative current bone height, current adjacent soft tissue state of the implants, with or without the success of the installations of the implants. We have done our survey with the clinical and radiolographical examinations and dental questionaries. The success and survival rate of the implants was evaluated. Results 1. Total number of the patients with the installation of the US II implants were 62. The 252 numbers of US II implants were installed on the 89 maxillary sinuses. The patient's mean age was 54.1 years old and there were 36 men and 27 women. 2. Total number of patients with the installation of SS II implant were 57. The 165 numbers of SS II implants were planted on the 80 maxillary sinuses. Their mean age was 48.7 years old and there were 37 men and 20 women. 3. The follow-up period was 30.7 months(21-49 mon) on average. The vertical bone loss of installed implants after the procedures of the maxillary sinus elevation was 1.1 mm on average in SS II and 1.3 mm on average in US II. There existed no statistical significance on each group. The mean enlarged bone height after the maxillary sinus floor elevation was 8.2 mm. 4. For the procedures of the maxillary sinus elevation, the Lateral approach technique occupied 87.1%, which was the most used one. In addition, the most frequently used transplanted bone was autogenous bone only which was 72.7% during the maxillary sinus floor elevation. 5. The complication of maxillary sinus floor elevation were perforation of sinus membrane, disesthesia on doner site, exposure of cover screw and exposure of maxillar bone. 6. The survival rate of US II and SS II after maxillary sinus floor elevation was 99.2% and 95.8%, respectively. And the success rate of US II and SS II after maxillary sinus floor elevation was 97.6% and 89.7%, respectively. Conclusion : On the evaluation of the analysis of our study, both US II and SS II implants showed the excellent clinical results by use of the procedures of maxillary sinus floor elevation.

• 한국전자파학회논문지
• /
• 제8권3호
• /
• pp.243-253
• /
• 1997

차량과 같은 지상 이동체 통신에서는 안테나에 도래하는 입사전파가 안테나의 수직평변면에 대해서 약 $60^{\circ}$ 정도 의 낮은 입사각을 가지므로 이를 효과적으로 수신할 수 있는 평면형 안테나를 제작하고 그 특성을 고찰하였다. 유전체 덮개층 효과를 이용한 설계를 하여 안테나의 기판층을 포함한 평면에서의 방사계가 영이 되지 않도록 함으로써 이러한 안테나의 설계가 가능하다. 주파수 1.2 GHz에서 70 MHz 정도의 대역폭을 갖고 저각도 입사전파를 수신할 수 있는 소형 마이크로스트립 안테나를 구현하였다.