• Journal of Astronomy and Space Sciences
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• 제22권3호
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• pp.233-242
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• 2005

66개의 근접촉쌍성(이하 NCBb)의 절대물리량과 궤도요소를 여러 목록으로부터 수집 분석하여 여러 물리량 사이의 상관관계와 NCBs의 물리적 특성을 조사하였다 NCBs의 질량비-광도비 관계는 $L_2/L_1{\lapprox}(M_2/M_1)^{1.45}$로 나타났으며 CE형에 더 근접한 특성을 보였다. NCBs의 여러 물리량 사이의 상관관계에 따르면 F형이 A형에 비하여 주성과 반성의 질량, 반경, 광도 및 온도의 차이가 작게 나타났다. NCBs의 H-R도에 따르면 A형이 F형에 비하여 다소 더 진화된 종년주계열(TAMS)에 가까이 나타나고 있다.

• 한국항공우주학회지
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• 제43권1호
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• pp.1-7
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• 2015

본 연구에서는 탄소섬유강화 복합재를 적층각과 적층순서에 따라 C-channel 형상에서 발생하는 스프링-인을 유한요소해석(ABAQUS)을 통해 예측하였다. 복합재 제작공정에서 냉각시의 큰 온도차 및 적층각에 따른 열팽창계수 및 화학적 수축계수의 차이로 인해 변형(스프링-인)이 발생한다. 이러한 변형은 제품의 품질과 직결되는 문제이며, 반드시 고려되어야 할 사항이다. 유한요소해석 시 CHILE모델과 화학적 수축을 고려한 서브루틴을 제작하여 적용하였으며, [0/X/Y/90]s case에 대해 X,Y를 $0{\sim}90^{\circ}$까지 변화시키며 각 case에 대한 스프링-인 발생량을 예측, 분석하였다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2002년도 학술대회지
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• pp.711-712
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• 2002

A numerical study of a hemodynamical model for the tumor angiogenesis is carried out. The tumor angiogenesis process is comprised of a sequence of events; secretion of tumor angiogenesis factor(TAF) from the solid tumor, degradation of the basement membrane of nearby blood vessels, migration and proliferation of the endothelial cells. The model takes into account the effect of TAF concentration and endothelial cell density, and their conservation equations are represented as a set of one-dimensional initial boundary value problems. These equations are discretized by using a finite difference method in which the second order schemes both in time and in space are used. The effects of the parameters contained in the model are Investigated extensively through the numerical simulation of the discretized model. The result for the typical case compares very well with the known result.

• 미생물학회지
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• 제34권1_2호
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• pp.58-63
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• 1998

'Contig 구성문제'는 random sequencing 단편들로부터 DNA 염기 서열의 정보를 밝혀낼 경우 발생하는 문제이다. 본 연구에서는 이러한 contig 구성문제를 해결하기 위한 알고리즘을 구성하였으며, X-window 응용 프로그램인 XFAP을 개발하였다. XFAP에서는 dimer 빈도 비교 방법을 사용하여 중첩 가능성이 없는 단편을 효과적으로 제거하였다. 이 방법은 단편 쌍 중첩에서 최소 수용 중첩 길이 내의 각 단편 사이의 dimer 빈도 차이를 이용하여 단편 쌍을 선별하는 것이다. 또한 단편 쌍 최대치 정렬 과정의 메모리 사용량을 줄이기 위해서, Myers 알고리즘을 적용하여 linear space에서 최대치 정렬을 구하는 방법을 사용하였다. 그리고 본 프로그램은 사용자들에게 편리한 그래픽 환경을 제공하기 위해서 Motif 라이브러리를 사용하여 X-window에서 구현되었다. 본 프로그램의 테스트 데이터를 생성하기 위해서 GenBank 데이터베이스에서 일정 길이의 염기 서열을 추출한 다음, sequencing시 일어날 수 있는 모든 오류들을 고려하여 단편 샘플을 생성하였다. 단편 샘플에 대해서 dimer 빈도 비교 방법의 효과 및 실행 시간을 측정하였다. 특히 dimer 빈도 비교 방법의 효율은 단편의 길이에 비례하여 증가하는 것으로 나타났다.

• Molecules and Cells
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• 제20권1호
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• pp.1-16
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• 2005

The peptidyl transferase center (PTC) is located in a protein free environment, thus confirming that the ribosome is a ribozyme. This arched void has dimensions suitable for accommodating the 3'ends of the A-and the P-site tRNAs, and is situated within a universal sizable symmetry-related region that connects all ribosomal functional centers involved in amino-acid polymerization. The linkage between the elaborate PTC architecture and the A-site tRNA position revealed that the A-to P-site passage of the tRNA 3'end is performed by a rotatory motion, which leads to stereochemistry suitable for peptide bond formation and for substrate mediated catalysis, thus suggesting that the PTC evolved by genefusion. Adjacent to the PTC is the entrance of the protein exit tunnel, shown to play active roles in sequence-specific gating of nascent chains and in responding to cellular signals. This tunnel also provides a site that may be exploited for local co-translational folding and seems to assist in nascent chain trafficking into the hydrophobic space formed by the first bacterial chaperone, the trigger factor. Many antibiotics target ribosomes. Although the ribosome is highly conserved, subtle sequence and/or conformational variations enable drug selectivity, thus facilitating clinical usage. Comparisons of high-resolution structures of complexes of antibiotics bound to ribosomes from eubacteria resembling pathogens, to an archaeon that shares properties with eukaryotes and to its mutant that allows antibiotics binding, demonstrated the unambiguous difference between mere binding and therapeutical effectiveness. The observed variability in antibiotics inhibitory modes, accompanied by the elucidation of the structural basis to antibiotics mechanism justifies expectations for structural based improved properties of existing compounds as well as for the development of novel drugs.

• 한국과학교육학회지
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• 제13권1호
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• pp.31-47
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• 1993

This study was intended to find the characteristics of the middle school students' thinking processes and problem spaces when they solved the physics problems. Ten ninth grade students in Chon-Buk Do, Korea were participated in this study. The researcher investigated their thinking processes in solving 5 physics problems on electric circuit. "Thinking aloud" method was used as a research method. The students' thinking processes were recorded using an audio tape recorder and transfered into protocols. The protocols were analyzed by problem solving process coding system which was developed by Lee(1987) on the basis of Larkin's problem solving process model. The results are as follows : (1) On the average 2.85 items were solved among 5 test items, and only one person could solve all of the items correctly. (2) Problems were solved in sequence of understanding the problem, planning, carrying out the plan, and evaluating steps regardless of the problem difficulty. (3) In regard to the thinking process steps, there was no difference between the good solvers and the poor ones. But in the detail performance of problem solving, the former was different from the latter in respect with using the design of general solving procedure. (4) The basic problem spaces by the item analysis were divided into two classes. One was the problem space by using Qualitative approach in problem solving, and the other was one by using Quantitative approach. As novices in physics problem solving, most of the students used the problem space by using the Quantitative approach.

• 대한치과교정학회지
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• 제24권2호
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• pp.233-246
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• 1994

The purpose of the present study was to investigate the difference of muscular activities of the tongue and lip muscles between anterior open-bite and normal occlusion during various function. Thirty eight subjects of 12.1-39.6 years were employed in this study : Eighteen subjects were anterior open-bites and tweenty subjects were normal occlusions. During rest position, maximum effort of lip sealing, command swallow of saliva and sucking & swallowing of juice, the electromyographic datas of the genioglossus, superior longitudinal muscle of tongue, upper and lower orbicularis oris were recorded and integrated with Medelec MS 25 electromyographic machine. Lateral cephalometric radiographs were taken on all subjects for the analysis of tongue posture and size. All data were recored and statistically processed. The findings of this study can be summerized as follows : 1. During the rest position, muscular activity of tongue was higher than that of lip muscle in open-bite, but no difference in normal occlusion group. 2. During the swallowing of juice, the activity of orbicularis oris was higher than that of genioglossus in open-bite. But the normal occusion was showed higher activity of tongue during the swallowing of juice. 3. The open-bite, compared to the normal occlusion, had higher value of tongue muscle activity during the rest position. 4. Compared to normal occlusion group, the open-bite had higher value of lip muscle activity during the sucking and swallowing of juice. 5. During the command swallow of saliva, the normal occlusion was showed harmonious swallowing pattern, but the open-bite showed much variation and disharmony in muscular contraction sequence, tended to absent of lip muscle activity. 6. At the lateral cephalometric radiographs, compared to the normal occlusion, the open-bite was showed lower tongue posture. But no difference was found in intermaxillary space. It is suggested that the open-bite, compared to the normal occlusion, had higher muscular activity of tongue during the rest position and various functions, showed lower tongue posture on the lateral cephalogram. In the development of anterior open-bite malocclusion, these factors may be an etiologic factor.

• 한국멀티미디어학회논문지
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• 제24권1호
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• pp.30-39
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• 2021

Research in the field of health lighting has continued to advance to reproduce the color temperature of natural light which periodically changes. However, most of this research could only reproduce a uniform circadian color temperature of natural light, therefore failing to realize the characteristics of the circadian cycle of color temperature difference by latitude and longitude. To reproduce the color temperature of natural light on which the characteristics of a region are reflected, the collection technology of real-time characteristics of natural light is needed. If the color temperatures which are not within a periodical pattern due to climate changes, etc., are measured, it will be difficult to judge the occurrence (presence) of the anomalies and to reproduce the circadian cycle of the color temperature of natural light. Therefore, this study proposes an algorithm for judging the anomalies in real time based on the sliding window to reproduce the color temperature of natural light. First, the natural light characteristics DB collected through the on-site measurement were analyzed, the differential values at a one-minute interval were calculated and examined, and then representative color temperature circadian patterns by solar terms were drawn. The anomalies were then detected by the application of the sliding window that calculated the deviation of the color temperature for the measured color temperature data set, which was collected through RGB sensors, while moving along the time sequence. In addition, the presence of anomalies was verified through the comparison study between the detection results and the representative circadian cycle of the color temperature by solar term. The judgment method for the anomalies from the measured color temperature of natural light was proposed for the first time, confirming that the proposed method was capable of detecting the anomalies with an average accuracy of 94.6%.

• 대한의용생체공학회:의공학회지
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• 제33권2호
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• pp.72-77
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• 2012

Phase Contrast MR Angiography(PC MRA) is excellent MRA technique for measuring the velocity of vessels in the human body. PC MRA need to at least four images for angiogram reconstruction and it caused longer scan time. Therefore, we used keyhole imaging combined PC MRA to reduce the scan time. However, keyhole imaging can lead the erroneous effects as loss of phase information or frequency discontinuous. In this study, we applied the keyhole imaging combined 2D PC MRA for improving the temporal resolution and also measured the velocity to evaluate the accuracy of phase information. We used 0.32T MRI scanner(Magfinder II, Scimedix, Korea). Using the 2D PC MRA pulse sequence, the vascular images for a human brain targeted on the Superior Sagittal Sinus(SSS) were obtained. We applied tukey window function for keyhole images to minimize the ringing artifact and erroneous factors that are induced frequency discontinuous and phase information loss. We also applied zero-padded algorithm to peripheral missing k-space lines to compare keyhole imaging results and the artifact power(AP) value was measured on the complex difference images to validate the image quality. Consider as based on our results, heavy image distortions and artifacts were shown until using at least 50% keyhole factor. Using above the 50% keyhole factors are shown well reconstructed and matched for magnitude images and velocity information measurements. In conclusion, we confirmed the image quality and velocity information of keyhole technique combined 2D PC MRA. Especially, measured velocity information through the keyhole imaging combination was similar to the velocity information of full sampled k-space image despite of frequency discontinuous and phase information loss in the keyhole imaging reconstruction process. Consequently, the keyhole imaging combined 2D PC MRA will give some clinical usefulness and advantages as improving the temporal resolution and measuring the velocity information via selecting the appropriate keyhole factor at low tesla MRI system.

• Journal of Plant Biotechnology
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• 제43권4호
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• pp.450-456
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• 2016

한국형 잔디에서는 다른 병에 비해 진전 속도가 빠르고 주로 뿌리에서부터 발병하여 잔디를 고사시키고 발병 후 구제하기 매우 어려운 라이족토니아잎마름병(라지패취)이 큰 문제로 대두되고 있다. 라이족토니아잎마름병(라지패취)은 Rhizoctonia solani AG2-2 (IV)병원균에 의해 발생하는데, 이 병원균에 강한 내병성 들잔디를 개발하기 위해 식물방어반응에 중요한 역할을 하는 것으로 알려진 PR-Protein 중 하나인 ${\beta}-1,3-glucanase$를 들잔디로부터 클로닝 하였다. ${\beta}-1,3-glucanase$는 바이러스나 균의 감염으로 인해 식물조직이 과민반응을 일으킬 때 세포내에서 생성되고 세포 외로 분비되어 세포 사이 공간에서 주로 병원균 저항성기능을 하는 것으로 알려져 있다. ${\beta}-1,3-glucanase$ 단자엽식물 중 내병성에 대한 연구가 되어있는 옥수수, 밀, 보리, 벼의 염기서열에서 공통으로 보존되어 있는 부분을 이용해 degenerate PCR을 수행하고 얻어낸 sequence를 통해 Full-length의 cDNA를 클로닝 하였다. E.coli overexpression을 수행하여 목표 단백질을 대량 정제하여 in vitro 활성 측정 및 항균테스트를 진행하였다. 또한, ZjGlu1 유전자의 기능을 해석하기 위해 각각의 유전자를 도입한 식물형질전환용 벡터를 제작하여 잔디 형질전환체 제작을 하였다. ZjGlu1 단백질을 이용하여 9개의 균주에 대해 항균활성 테스트를 진행 한 결과 R. cerealis, F. culmorum, R.solani AG-1 (1B), T. atroviride 에서 항균활성을 보였으며, 형질전환체를 이용해 18s 유전자의 발현량을 상대로 한 각 유전자의 기관별 발현량은 크게 차이없이 모든기관에 발현되는 것을 확인할 수 있었다.