• Nuclear Engineering and Technology
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• v.55 no.10
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• pp.3775-3786
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• 2023

Mixing Vane Grid (MVG) is one of the most important structures in fuel assembly due to its high performance in mixing the coolant and ultimately increasing Critical Heat Flux (CHF), which avoids the temperature rising suddenly of fuel rods. To evaluate the mixing performance of the MVG, a Total Diffusion Coefficient (TDC) mixing coefficient is defined in the subchannel analysis code. Conventionally, the TDC of the spacer grid is obtained from the combination of experiments and subchannel analysis. However, the processing of obtaining and determine a reasonable TDC is much challenging, it is affected by boundary conditions and MVG geometries. In is difficult to perform all the large and costing rod bundle tests. In this paper, the CFD method was applied in TDC analysis. A typical 5 × 5 MVG was simulated and validated to estimate the mixing performance of the MVG. The subchannel code was used to calculate the TDC. Firstly, the CFD method was validated from the aspect of pressure drop and lateral temperature distribution in the subchannels. Then the effect of boundary conditions including the inlet temperature, inlet velocities, heat flux ratio between hot and cold rods and the arrangement of hot and cold rods on MVG mixing and TDC were studied. The geometric effects on mixing are also carried out in this paper. The effect of vane pattern on mixing was investigated to determine which one is the best to represent the grid's mixing performance.

• Archives of Craniofacial Surgery
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• v.25 no.2
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• pp.77-84
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• 2024

Background: The facial artery is an important blood vessel responsible for supplying the anterior face. Understanding the branching patterns of the facial artery plays a crucial role in various medical specialties such as plastic surgery, dermatology, and oncology. This knowledge contributes to improving the success rate of facial reconstruction and aesthetic procedures. However, debate continues regarding the classification of facial artery branching patterns in the existing literature. Methods: We conducted a comprehensive anatomical study, in which we dissected 102 facial arteries from 52 embalmed and formaldehyde-fixed Vietnamese cadavers at the Anatomy Department, University of Medicine and Pharmacy, Ho Chi Minh City, Vietnam. Results: Our investigation revealed eight distinct termination points and identified 35 combinations of branching patterns, including seven arterial branching patterns. These termination points included the inferior labial artery, superior labial artery, inferior alar artery, lateral nasal artery, angular artery typical, angular artery running along the lower border of the orbicularis oculi muscle, forehead branch, duplex, and short course (hypoplastic). Notably, the branching patterns of the facial artery displayed marked asymmetry between the left and right sides within the same cadaver. Conclusion: The considerable variation observed in the branching pattern and termination points of the facial artery makes it challenging to establish a definitive classification system for this vessel. Therefore, it is imperative to develop an anatomical map summarizing the major measurements and geometric features of the facial artery. Surgeons and medical professionals involved in facial surgery and procedures must consider the detailed anatomy and relative positioning of the facial artery to minimize the risk of unexpected complications.

• Korean Journal of Optics and Photonics
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• v.35 no.4
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• pp.164-169
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• 2024

We applied recursive numerical computation to create a basic design of a camera optical module for mobile phones. To enhance the resolution performance for a 38-degree field of view, we constructed the optical system with six non-spherical lenses. However, to increase its applicability to a compact mobile phone, we limited the overall length to 5 mm in the design. Using the data obtained from the basic design, we proceeded with optimization design using the Zemax design tool. The optimized optical system achieved a resolution performance with a modulation transfer function value of more than 19% for a 280 lines/mm pattern and image distortion within 1.0% for all wavelength rays. In this paper, we verify the feasibility of using recursive numerical computation for the basic design of a compact mobile phone camera.

• Economic and Environmental Geology
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• v.42 no.6
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• pp.635-643
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• 2009

In this paper, a Quaternary fault is described, which is developed in the mid-eastern part of Ulsan Fault Zone, near the southern Gaegok-ri, Oedong-eub, Gyeongju, Korea. The Gaegok 6 fault is developed along the contact between Early Tertiary granite and Quaternary gravel deposit overlying unconformably the granite. The fault strikes $N02^{\circ}{\sim}22^{\circ}E$ and dips $45^{\circ}{\sim}80^{\circ}$ to the west. This fault has a 30~50 cm wide cataclastic shear zone with gouge zone, mixed with Quaternary sediments and fault breccia of granite. In the main Quaternary fault plane, the orientation of striation is $17^{\circ}$, $356^{\circ}$, indicating a dextral strike-slip faulting with some normal component. There is another striation ($78^{\circ}$, $278^{\circ}$ and $43^{\circ}$, $270^{\circ}$) with reverse-slip sense, developed on the subsidiary plane which cuts the main Quaternary fault plane. In brief, the fault has been developed between the granite in the western part and the Quaternary gravel deposit in the eastern part. The western block of fault is uplifted. The striations and movement senses of faults indicate multiple compressional stages in this region. The fault has a similar orientation, westward dipping geometric pattern, and reverse sensed kinematic pattern with Gaegok 1 fault developed in the north. Thus, the Gaegok 6 fault is probably a southern extension of Gaegok 1 fault.

• Journal of the Korean Society of Costume
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• v.52 no.1
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• pp.53-67
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• 2002

자연을 분석함으로써, 얻어진 기하학적 패턴은 이미 자연의 질서를 포함하고 있는 논리적이고 합리적인 기본형이기 때문에 간결하며 시각적으로 명쾌감을 준다. 이러한 기하학적 패턴은 복식 디자인에 있어서 20 세기 이후 여러 디자이너의 작품을 통해 재구성되어 현대적 이미지를 나타내는 중요한 모티브가 되고 있으며, 다양한 기법과 재료로 형성화하여 도입되고 있다. 이에 본 연구는 복식의 문양, 실루엣, 디테일에 사용되고 있는 기하학적 패턴을 연구함으로써 기하학적 패턴의 새로운 조형가치를 고찰하였다. 먼저 기하학의 용어 정의를 하였고 기하학적 패턴의 유형과 표현 기법을 분석하고 정리하여 현대 패션에 나타난 기하학적 패턴의 조형미와 그것을 바탕으로 패션 이미지를 추론해 보았다. 현대 패션에 나타난 기하학 패턴을 분석해 보면 유형으로는 첫째, 기하하적 문양으로 복식디자인에 있어서 주로 평면적인 형태로 많이 나타나지만, 크기가 다르고 동일한 기하학적 패턴을 조합시킴으로서 평면적인 형태에 공간감을 부여하기도 하며, 같은 기하학적 패턴의 표면이라도 배치구조에 의해 직선 혹은 사선으로 지각되므로 전혀 다른 이미지를 주었다. 또한 현대 패션에 나타난 기하학적 패턴이 종류는 세로 스트라이프, 가로 스트라이프, 격자 문양, 원, 사선 스트라이프, 마름모, 사각형, 삼각형 등의 순서로 많이 나타났다. 둘째, 색채는 단색의 복식에 강한 대비가 이루어지는 색상으로 표현되어 역동감과 유연한 운동감을 나타났다. 셋째, 기하학적 실루엣으로 단순한 라인의 형태를 나타내거나 입체적이고 부조적인 형태로 구성되어 전체적인 실루엣으로 사용되어 강한 조형감각을 보여주는데 원형을 이용한 실루엣이 가장 많았으며 사각형을 이용한 실루엣, 삼각형을 이용한 실루엣 순서로 나타났다. 넷째, 기하학적인 디테일로 복식의 어느 한 부분에 장식적으로 사용되거나 입체적 형태로 부출 되어 부조적인 느낌을 주는데 소매에 가장 많이 나타났으며 앞여밈, 칼라, 밑단, 주머니 순서로 장식되었다. 다섯째, 현대 패션에 표현된 기하학적 패턴의 표현기법으로는 프린팅, 퀼팅, piece기법, 패치워크, 엮기, 꼴라쥬, 아플리케 순서로 많이 나타났다. 위의 분석을 토대로 기하학 패턴을 활용한 디자인에 내재된 조형의지는 다음과 같이 정리되었다. 첫째, 기하학적 패턴이 지닌 단순성과 경직성을 완화하기 위하여 여러 가지 패브릭을 조합시켜 입체적인 표면효과로 시각적인 착시효과를 극대화하였다. 둘째, 표현기법은 입체파적 표현주의의 특성의 하나로 복시에 사용되는 소재의 왜곡으로 설명할 수 있으며, 새롭고 실험적인 소재의 도입으로 인해 의외성과 부조화를 유발시키는 통시에 유희직인 일면도 지니는 일종의 그로테스크를 나타냈다. 이상에서 정립된 조형의지를 바탕으로 현대 패션에 나타란 기하학 패턴은 절제된 단순함과 명확성으로 단순미가 유추되었고 강한 색상대비로 인한 시각적 집중효과로 주목성을 가지며 재현이 가능하므로 반복성이 유추되었다. 그리고 표준영역이 없는 창의적 표현으로 풍부한 독창성을 보여주고 있다. 또한 내재된 패션 이미지를 분석해 보면 정확함과 차가움의 의미를 지닌 이지적 이미지와 우주의 질서를 반영하는 상징적 이미지, 복잡한 자연으로부터 간결한 형태로의 경향성이 이루어낸 인공적 이미지를 느낄 수 있었으며, 미래적 이미지와 전통적 이미지의 상반된 개념의 이미지를 같이 내포하고 있음을 추론할 수 있었다. 이와 같이 현대 패션에 표현된 기하학적 패턴은 복식을 조형예술 분야로 확실히 인식시키고 발전시키는 데 중요한 촉매제 역할을 담당하고 있으며 또한 많은 디자이너들에게 창조적 욕구를 불러일으키고 영감을 주는데 중요한 모티브를 제공하고 있다.

• Spatial Information Research
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• v.14 no.1 s.36
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• pp.163-176
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• 2006

The concept of 'spatial association' explains spatial distribution pattern of geographical phenomenon based on similarity with neighborhoods, as in the Tobler's Law of Geography: 'Everything is related to everything else, but near things are more related than distant things.' In this study, we develop a time-series exploratory analysis tool for discovering temporal patterns of spatial association by combining spatial statistics and geo-visualization, and thus present a possibility to support spatial decision-making process. As for the spatial proximity weight matrix indispensable to measuring global and local spatial association, we employ a variety of flexible weighting schemes using geometric characteristics of areal unit. In addition, we renovate the existing visualization methods for more effective understanding of the procedures and results of time-series analysis on spatial association: for instance, temporal parallel coordinate plot with box plot, animated map for spatial association, and 3D Moran scatterplot. The feasibility of our system is verified by time-series analysis experiments on the spatial association of land price fluctuation rate for all administrative units in Korea, $1995{\sim}2004$.

• Journal of the Korean Association of Geographic Information Studies
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• v.16 no.2
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• pp.47-64
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• 2013

Landscape structure changes over the past three decades were determined with land use and land cover(LULC) maps, and their relationships with mean air temperature time series were the analyzed for the Busan metropolitan area and South Kyeongsang Province, Korea. The geometric structures of the LULC data were quantitatively represented based on FRAGSTATS, a spatial pattern analysis program for quantifying landscape structure. FRAGSTATS-derived landscape metrics confirmed that there were major changes in LULC and landscape fragmentation in the region. Meteorological observation records showed that mean air temperature had increased from $14.1^{\circ}C$ in the 1990's to $14.8^{\circ}C$ in the 2000's in Busan. For South Kyeongsang Province, they increased from $13.2^{\circ}C$ to $13.9^{\circ}C$ during the same time period. These long-term temperature changes are correlated with typical spatial pattern changes of LULC in the southeastern region of the country. Spatial metrics analysis showed that urban area expanded from 9.7% to 26.8% of Busan while forest and agricultural land decreased by 9.6% and 14.9%, respectively over the past thirty years. The significant urbanization are tightly associated with deforestation, removal of agricultural land, and fast temperature increases since the 1990's. The urban area of South Kyeongsang Province rapidly increased, and it became 12 times as large as it was. The degree of temperature increases differed among three different sub-regions. The temperature increasing rate was lowest in the coastal region while the colder mountainous region had the highest figure.

• The Journal of the Petrological Society of Korea
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• v.22 no.2
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• pp.209-217
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• 2013

Fe-Ti ore bodies occur in the western part of the Sancheong anorthosites around Banggok-ri, Sancheong, Korea. Within ore bodies, a several centimetric size of anorthositic breccia are enclaved by ore-bearing mafic part and deformed strongly as a sigmoidal form by ductile shearing. The ore bodies have a general N-S trending foliations with westward dipping directions. The foliation developed in the ore bodies cut the foliation in anorthosites. The stretching lineations are well developed in the foliated plane of the ore bodies, showing ENE-trending with gentle plunging angle to the ESE direction. The sigmoidal patterns of anorthositic breccia in the ore bodies indicates the top-to-the-eastnortheastward shearing. Thus, in this study area the relationship between the geometric pattern and the ductile deformation is an important fact to understand the Sancheong Fe-Ti mineralized zone, Korea.

• Polymer(Korea)
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• v.26 no.5
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• pp.691-700
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• 2002

Interstitial therapy using biodegradable polymeric device loaded with anticancer agent can deliver the drug to the tumor site at high concentration, resulting in an increase of therapeutic efficacy. 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU, carmustine) is most commonly used as chemotherapeutic agent for brain tumors. The design of implantable device is regarded as an important factor lot the efficient delivery of antitumor agent to targeting site. In order to control the release profile of drug, the release pattern of BCNU with the changes of various dimension and additives was investigated. The PLGA wafers containing 3.85, 10, 20 and 30% of BCNU were prepared in various shape (diameter of 3, 5 and 10 mm, thickness of 0.5, 1 and 2 mm) by direct compression method. In vitro drug release profile of BCNU-loaded PLGA wafers could be controlled by changing the dimension of wafers such as initial drug content, weight, diameter, thickness, volume and surface area of wafers, as well as PLGA molecular weight and additives. Drug release from BCNU-loaded PLGA wafers was facilitated with an increase of BCNU-loading amount or presence of poly(N-vinylpyrrolidone)(PVP) or sodium chloride (NaCl). The effects of various geometric factors and additives on the BCNU release pattern were confirmed by the investigation of mass loss and morphology of BCNU-loaded PLGA wafers.

• The Journal of Engineering Research
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• v.1 no.1
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• pp.5-14
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• 1997

The purpose of thesis is to analyze the radiation characteristics of an offset gregorian antenna in order to design the satellite-loaded antenna. In order to compute the radiation pattern of the sub-reflector, the reflected wave is obtained by GO(Geometric Optics) at an arbitrary shaped sub-reflector. Then the total radiation EM wave is obtained by summing the diffracted fields obtained by UTD(Uniform Geometrical Theory of Diffraction) and the GO fields. In order to calculate the far field radiation pattern of the main reflector, the radiation integral equation is derived from the induced current density on reflector surface using PO(Physical Optics). The kernel is expanded in terms of Jacobi-Bessel series for increasing the computational efficiency, then the modified radiation integral is represented as the double integral equation independent of observation points. When the incident fields are assumed to be x-or y-polarized field, the characteristics of radiation patterns in the gregorian antenna is analyzed in case of the main reflector having the focal length of 62.4$\lambda$, diameter of 100$\lambda$, and offset height of 75$\lambda$, and the sub-reflector having the eccentricity of 0.501, the inter focal length og 32.8$\lambda$, the horn axis angle of $9^{\circ}$ and the half aperture angle of $15.89^{\circ}$. The cross-polarized level and side lobe level in the offset geogorian reflector are reduced by 30dB and 10dB, respectively, in comparison with those of the offset parabolic antenna.