경기만 석모수도 수로제방 조간대층에 발달하는 경사이질암상층리의 퇴적학적 연구 - 오일샌드 탐사 적용가능성

최경식,전승수,김성필,박세진,Choi, Kyung-Sik,Dalrymple, R.W.,Chun, Seung-Soo,Kim, Sung-Pil,Park, Se-Jin 한국석유지질학회 2005 한국석유지질학회지 Vol.11 No.1

경기만 북부 석모수도 수로제방에 40 m 두께의 조수로 포인트바(tidal point bar) 퇴적층이 발달하고 있다. 수로 제방은 위로 볼록한 형태를 가지고 있으며 간헐적으로 간조선 근방에서 파랑기원의 침식면이 나타난다. 경사이질암상층리는 최대 25 m 두께로 발달하며 수로 방향으로 경사도는 14도에 달한다. 경사이질암상층리의 하부에는 밀물방향성을 갖는 사층리층이 발달한다. 석모수도는 썰물우세 수로이지만 밀물 방향성의 사층리가 우세하게 발달하는데 이것은 조수로의 전형적인 특성인 창조류와 낙조류리 상호 회피성에 기인한다. 경사이질암상층리는 세립사와 점토의 교호층리로 구성되며 상향 세립화의 경향성을 보인다. 석모수도의 거대한 크기와 한강으로부터의 멀리 떨어진 위치, 강한 조류의 영향으로 인해 퇴적층 내에는 한강의 계절적인 유량변동이 기록되지 않는다. An occurrence of inclined heterolithic stratification (IHS) is described from a tidal point bar in a 40-m-deep distributary of the macrotidai, Han River delta, Korea. The channel bank demonstrates a convex-upward profile with intermittent presence or wave-formed scarps and terraces near the low-water level. The vertical succession of IHS is approximately 25 m thick and dips into the channel with angles reaching up to $14^{\circ}C$. The IHS overlies 15 m of trough cross-bedded sand deposited in the channel bottom. Even though the channel as a whole is ebb dominated, the preserved cross bedding is predominantly flood directed because the mutually evasive nature of the ebb and flood currents causes the point bar surface to be flood dominated. The IHS itself consists of inter-stratified fine sand, sandy silt, and silt with an fining-upward textural trend. Seasonal discharge variations of the Han River are not obvious in the deposits, because tile large size, distal location, and energetic tidal environment of the studied channel reduces the impart of river-stage fluctuations.

레이저조사 후 망막에서의 디스인테그린 효과

최경식,김준순,박성희,Kyung Seek Choi,Joon Soon Kim,Song Hee Park 대한안과학회 2006 대한안과학회지 Vol.47 No.11

Purpose: To investigate weather an administrated inhibitor (disintegrin) of angiogenic factors inhibits the development of laser-induced experimental choroidal neovascularization (CNV) in rat model. Methods: Experimental CNV was induced by red argon laser photocoagulation in the eyes of 10 Brown Norway rats. The rats were divided into two groups, the disintegrin (flavoridin)-treated group and control group. Fundus photography and fluorescein angiography were performed to identify late leakage after two weeks of laser photocoagulation. Three days after fluorescein angiography, the expression of vascular endothelial growth factor (VEGF) was identified by immunohistochemical stain. Results: CNV-related fluorescein leakage appeared in forty-four (18 in the flavoridin-treated group, 26 in the control group) of 64 laser spots delivered to the 10 eyes that were tested at two weeks post-treatment. Expression of VEGF on laser-induced CNV lesions was reduced in the flavoridin-treated group. Conclusions: The results of this study suggest that disintegrin is an inhibitor of ocular angiogenesis; disintegrin reduced CNV in laser-induced experimental model. We expect that disintegrin may have a potent effect in age-related macular degeneration.

6.25 전쟁 시 중공군의 역할과 북한 유사시 중국의 역할 전망

최경식,Choi, Kyung-Sik 대전대학교 군사연구원 2010 군사학연구 Vol.8 No.-

The year 2010 is the 60th anniversary commemorating the Korean War. China intervened in the Korean War with the logics such as "To Resist the U.S.'s Aggression and Aid North Korea," "Save Endangered Home & defend Nation," and "If the Lips Are Gone, the Teeth Will Be Exposed to the Cold or If One of Them Falls, the Other is in Danger." However, China had a deep and long connection with North Korea through 1st Chinese Civil War, war against Japan imperialism, and 2nd Chinese Civil War. China has consulted with Kim Il-sung on his invasion of South Korea at the initial stage of development and played a casting vote role in the execution of the invasion plan. During the Korean War, the PLA supported the North Korea's regime by its action, and made the Korea Peninsula divide into two semi-permanently. Even after the war, China continues to maintain relations with North Korea by helping North Korea build the Kim Il-sung's Kingdom. Currently, whenever any issue related to North Korea rises in the international society, China definitely gets involved in those issues and exercises its power. Conditionally 'either armed aggression or, and wartime' in North Korea, China would follow the "Clause of Military Auto Intervention." In addition, China is very likely to establish refugee camps for North Koreans in the Northeastern-Three-Province and to provide rear bases or guerrilla camps for pro-Chinese sects. Furthermore, voluntarily playing a role as spokesman of North Korean Regime in the international society, China will exercise enormous influence on the reunification of the Korean Peninsula.

오일샌드 탐사 및 개발을 위한 현생유사퇴적환경 연구의 중요성

최경식,Choi, Kyung-Sik 한국석유지질학회 2008 한국석유지질학회지 Vol.14 No.1

캐나다 오일샌드는 사우디아라비아의 원유 부존량과 맞먹을 만큼 방대한 매장량을 자랑하고 있는 대표적인 비재래 원유이다. 오일샌드 저류층을 구성하는 퇴적층은 조수우세 퇴적환경에서 형성된 수로충진층으로 구성되어 있다. 조수퇴적층은 외부에서 작용하는 에너지의 상호작용 결과 공간적으로 복잡하고 불균질한 물성을 가지는 것이 특징적이다. 오일샌드의 성공적인 개발을 위해서는 저류층내 물성의 공간적인 분포에 대한 심도있는 이해를 기반으로 하는 공법이 적용되어야 한다. 오일샌드 저류층의 특성화를 위해 사용되는 지질모델은 고기와 현생의 유사퇴적환경에 대한 비교연구를 기반으로 구축되며, 특히 현생 유사퇴적환경 연구는 저류층의 형성과정과 저류층 물성의 불균질성을 제어하는 외부 기구에 대한 정보를 제공하므로 정교한 지질모델 구축에 필수적인 요소로 인식되고 있다. 한국 서해안 조수우세퇴적환경은 캐나다 오일샌드 저류층이 형성된 퇴적환경과 유사한 것으로 판단되며, 이암파편층 분포, 퇴적상 및 층서 아키텍쳐 등과 같은 오일샌드 저류층 특성화에 필수적인 개념의 정립에 중요한 단서를 제공하는 것으로 평가받고 있어 그 중요성이 최근 큰 주목을 받고 있다. Oil sands in Canada are representative example of unconventional resources whose reserve estimates are as large as those in Saudi Arabia. Typical reservoir rocks of oil sands consist of channel-related deposits formed in a tide-dominated depositional setting. The tidal deposits are commonly characterized by spatially complicated and heterogeneous properties. Successful engineering methods to develop oil sands require in-depth understanding in the spatial distribution of reservoir properties. Geological model for oil sand reservoir characterization can be built on the basis of comparative studies of ancient and modem analogues. In particular, modern analogue studies become increasingly indispensable, since they provide better understanding in the reservoir-rock forming process and more importantly in the external mechanism responsible for the reservoir heterogeneity. Tide-dominated environment along the west coast of Korea is considered as one of the most excellent modem analogues of oil-sand forming depositional environment. Korean tidal environment provides insights on the origin of mud breccia, facies and stratigraphic architecture which are key issues to the characterization of oil sand reservoirs.

보조 도선과 Annular Gap을 추가한 PCS 대역 마이크로스트립 패치 안테나 설계

최경식,윤종섭,류미라,이원희,허정,Choi, Kyoung-Sik,Yoon, Jong-Soeb,Ryu, Mi-Ra,Lee, Won-Hui,Hur, Jung 한국전자파학회 2001 한국전자파학회논문지 Vol.12 No.3

In this paper, we designed microstrip patch antenna to enhance the weak point of general microstrip patch antenna that has narrow bandwidth and analyzed that. To reduce reactance in probe feed antenna, capacitive gap added to the patch. Using single patch and auxiliary wire, makes dual frequency resonant. So bandwidth is improved and gain also becomes higher. To verify with experiment, PCS band antenna is designed, fabricated. For PCS band antenna, bandwidth is 180 MHz in VSWR<1.5 and gain is 8.6 dBi. 본 논문에서는 마이크로스트립 패치안테나의 단점인 협대역을 개선하기위해 안테나를 설계, 분석하였다. Probe 급전 방식의 안테나에서 reactance 성분을 줄이기 위해 capacitive gap을 추가하였다. 단일 패치와 보조도선을 사용하여 이중공진모드를 형성하였다. 이로 인해 대역폭이 증가되었고, 이득도 향상되었다. 이를 실험적으로 검증하기위해 PCS 주파수 대역의 안테나를 설계, 제작하였다. 제작된 PCS 주파수 대역 안테나의 측정 결과 는 VSWR,1.5에서 대역폭이 190 MHz이고, 이득은 8.6dB이다.

고주파 맥놀이 신호의 포락선 위상차를 이용한 음향식 헬멧자세추정 기법

최경식,김상석,박찬흠,양준호,Choi, Kyong-Sik,Kim, Sang-Seok,Park, Chan-Heum,Yang, Jun-Ho 한국군사과학기술학회 2013 한국군사과학기술학회지 Vol.16 No.1

Helmet Mounted Display(HMD) has great advantages on the navigation and mission symbologies for the pilot's forward looking display and, therefore, has been remarkably drawing attention as the up coming display of the next generation aircraft. The essential technology to process the Line of Sight-Foward(LOS-F) data in real-time is to estimate exact helmet situation and position. In this paper, we research a acoustic helmet tracking technique. For the reason that mechanical acoustic noises might interfere with Helmet Tracking System(HTS) and unnecessary acoustic noises are inevitable when using acoustic technique, this approach has not been adapted. In order to overcome this problem. We propose that acoustic wave of which the wave length is longer than audio frequency and, especially, we used beating signal envelope which is composed of two close high frequency.

컴퓨터 생성 홀로그래픽 디퓨저의 설계

최경식,윤진선,김남,Choi, Kyong-Sik,Yoon, Jin-Seon,Kim, Nam 대한전자공학회 2001 電子工學會論文誌-SD (Semiconductor and devices) Vol.38 No.5

본 논문에서는 높은 회절 효율과 균일도를 갖는 컴퓨터 생성 홀로그래픽 디퓨저를 수정된 반복 푸리에 변환 알고리즘으로 설계하였다. 컴퓨터 생성 홀로그래픽 디퓨저를 설계하기 위한 새로운 방법으로 위상형 홀로 그램들을 대칭, 결합시킴으로서 계산시간을 감소시켰고 재생되는 신호 영역을 확장하였다. 설계한 16 위상형 홀로그래픽 디퓨저는 85.20%의 높은 회절 효율과 2.43%의 균일도, 18.97[㏈]의 평균 신호대 잡음비를 나타내었다. 또한, 컴퓨터 생성 홀로그래픽 디퓨저와 128 단계를 갖는 유사 랜덤 위상 디퓨저를 회절 효율과 균일도 측면에서 비교하였고, 홀로그래픽 디퓨저와 차세대 디스플레이용 소자로서 유용하게 이용될 수 있음을 제시하였다. In this paper, computer generated holographic diffuser with high diffraction efficiency and uniformity was designed by the modified iterative Fourier transform algorithm. Newly proposed method to design a CGHD is to flip and to combine BPHs or MPHs, so it makes the computation time decreased and it makes the reconstructed signal area enlarged. The designed sixteen phase holographic diffuser had the high diffraction efficiency of 85.20%, the uniformity of 2.43%, and the average signal to noise ratio of 18.97[㏈]. Also, we compared the CGHD with a 128 level pseudo random phase diffuser about the diffraction efficiency and the uniformity. The proposed diffuser can be provided good performance for a holographic diffuser and a next-generation display device.

Development of Independent Target Approximation by Auto-computation of 3-D Distribution Units for Stereotactic Radiosurgery

최경식,오승종,이정우,김정기,서태석,최보영,김문찬,정현태,Choi Kyoung Sik,Oh Seung Jong,Lee Jeong Woo,Kim Jeung Kee,Suh Tae Suk,Choe Bo Young,Kim Moon Chan,Chung Hyun-Tai Korean Society of Medical Physics 2005 의학물리 Vol.16 No.1

정위적 방사선 수술은 한 번에 두 개내 병소에는 고선량의 방사선을 조사하면서, 주위 정상조직에는 최소한의 방사선이 조사되도록 시술하는 치료기법이다. 본 연구는 정위적 방사선 수술시 자동적 치료계획을 수행하기 위하여, 선형가속기와 감마나이프의 다수의 회전중심점을 이용하는 치료계획에 대한 물리적 격자구조에 기반한 새로운 방법을 개발하였다. 최적의 방사선 수술계획은 많은 빔관련 변수들의 조합으로서 만들어진다. 본 연구에서는 선형가속기와 감마나이프 수술시 빔 측면도의 50% 수준에서의 선량분포가 콜리메이터/헬멧의 구멍 크기와 일치하는 점을 이용하여 하나의 회전중심점을 중심으로 선량분포를 구형으로 모델화시켰다. 그리고, 다수의 회전중심점들은 병소내 위치와 크기를 고려한 정육면체 구조와 1×1×1 ㎣의 체적소 단위의 계산에 의해 자동적으로 배치시켰다. 이 기법에 의한 치료계획 방법은 선량체적히스토그램, 선량의 일치성, 선량의 균질성의 병소내 선량분포로서 평가되었다. 그 결과, 새로운 기법은 불규칙한 병소들에 대하여 프로그램 시스템에 의해 빠르게 다수의 회전중심점들을 배치시켰다. 또한, RTOG의 권고사항에 언급된 병소내 선량분포의 일치성, 균질성이 기준을 잘 만족하였고, 병소들은 50% 이상의 등선량 곡선 내에 포함되었다. 이와 같은 성과는 불규칙하게 형성된 병소와 선형가속기나 감마나이프와 같은 다른 치료 장치 기법들에서 특별한 제약없이 보편적으로 적용이 될 수 있을 것으로 생각된다. The stereotactic radiosurgery (SRS) describes a method of delivering a high dose of radiation to a small tar-get volume in the brain, generally in a single fraction, while the dose delivered to the surrounding normal tissue should be minimized. To perform automatic plan of the SRS, a new method of multi-isocenter/shot linear accelerator (linac) and gamma knife (GK) radiosurgery treatment plan was developed, based on a physical lattice structure in target. The optimal radiosurgical plan had been constructed by many beam parameters in a linear accelerator or gamma knife-based radiation therapy. In this work, an isocenter/shot was modeled as a sphere, which is equal to the circular collimator/helmet hole size because the dimension of the 50% isodose level in the dose profile is similar to its size. In a computer-aided system, it accomplished first an automatic arrangement of multi-isocenter/shot considering two parameters such as positions and collimator/helmet sizes for each isocenter/shot. Simultaneously, an irregularly shaped target was approximated by cubic structures through computation of voxel units. The treatment planning method by the technique was evaluated as a dose distribution by dose volume histograms, dose conformity, and dose homogeneity to targets. For irregularly shaped targets, the new method performed optimal multi-isocenter packing, and it only took a few seconds in a computer-aided system. The targets were included in a more than 50% isodose curve. The dose conformity was ordinarily acceptable levels and the dose homogeneity was always less than 2.0, satisfying for various targets referred to Radiation Therapy Oncology Group (RTOG) SRS criteria. In conclusion, this approach by physical lattice structure could be a useful radiosurgical plan without restrictions in the various tumor shapes and the different modality techniques such as linac and GK for SRS.

CFD를 이용한 온실 난방용 지열 히트파이프 유동해석

최경식 ( Kyeongsik Choi ),박성완 ( Sungwan Park ),선우훈 ( Hoon Seonwoo ) 한국농업기계학회 2021 한국농업기계학회 학술발표논문집 Vol.26 No.2

Most of domestic farmers use fossil fuels as an energy source for greenhouse heating. However, the use of fossil fuels also causes environmental problems such as air pollution. Accordingly, geothermal heat pump systems, one of new and renewable energies with low risk of environmental pollution and free from depletion, need to be applied. Actually, simulation techniques that analyze fluid flow and heat transfer based on numeric calculations are mainly used to shorten time and cost to predict various environmental conditions. In this study, the appropriate diameters of the pipes interpreting the geothermal heat energy into greenhouse heating were calculated according to drilling depth using the commercially available CFD program ANSYS FLUENT. By setting the flow rate and temperature value in the pipe, data such as the energy transfer process, average flow rate, and temperature change of the model to can be analyzed and checked. More efficient geothermal heat pump can be expected through design change and application based on the flow analysis of this process.

서안사변(西安事變)에서 중국공산당이 끼친 영향 분석

최경식 ( Kyung Sik Choi ) 한국군사학회 2008 군사논단 Vol.53 No.-