• Title/Summary/Keyword: Surface patterns

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Changed Relationship between Snowfall over the Yeongdong region of the Korean Peninsula and Large-scale Factors

  • Cho, Keon-Hee;Chang, Eun-Chul
    • Journal of the Korean earth science society
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    • v.38 no.3
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    • pp.182-193
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    • 2017
  • A typical snowfall pattern occurs over the east coastal region of the Korean Peninsula, known as the Yeongdong region. The precipitation over the Yeongdong region is influenced by the cold and dry northeasterly wind which advects over warm and moist sea surface of the East Sea of Korea. This study reveals the influence of large-scale factors, affecting local to remote areas, on the mesoscale snowfall system over the Yeongdong region. The National Centers for Environmental Prediction-Department of Energy reanalysis dataset, Extended Reconstructed sea surface temperature, and observed snowfall data are analyzed to reveal the relationship between February snowfall and large-scale factors from 1981 to 2014. The Yeongdong snowfall is associated with the sea level pressure patterns over the Gaema Plateau and North Pacific near the Bering Sea, which is remotely associated to the sea surface temperature (SST) variability over the North Pacific. It is presented that the relationship between the Yeongdong snowfall and large-scale factors is strengthened after 1999 when the central north Pacific has warm anomalous SST. These enhanced relationships explain the atmospheric patterns of recent strong snowfall years (2010, 2011, and 2014). It is suggested that the newly defined index in this study based on related SST variability can be used for a seasonal predictor of the Yeongdong snowfall with 2-month leading.

Surface Microtopography of Pyrophyllite Crystals from Gussi Deposit, Korea (전남 구시광산에서 산출하는 엽납석 결정의 표면 미세형태)

  • Mayumi Jige;Ryuji Kitagawa;Hwang, Jin-Yeon
    • Journal of the Mineralogical Society of Korea
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    • v.17 no.2
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    • pp.115-121
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    • 2004
  • The surface microtopography of pyrophyllite collected from the Gussi deposit, Korea was observed by mean of transmission electron microscopy (TEM) with the gold decoration technique. As results, closed step patterns with malformed circular islands were characteristically observed on the (001) surface of pyrophyllite, contrasting with spiral step patterns common in illite and kaolinite. Gussi pyrophyllite was likely crystallized from hydrothermal solution of higher temperature and/or higher supersaturation than those of other clay minerals. Comparing with micro-topographies of pyrophyllite from the Shokozan and the Uku deposits, southwest Japan, growth mechanism of Gussi pyrophyllite is almost equivalent to those from the Shokozan and the Uku deposits.

Evolution of Genetic Polymorphisms of Plasmodium falciparum Merozoite Surface Protein (PfMSP) in Thailand

  • Kuesap, Jiraporn;Chaijaroenkul, Wanna;Ketprathum, Kanchanok;Tattiyapong, Puntanat;Na-Bangchang, Kesara
    • Parasites, Hosts and Diseases
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    • v.52 no.1
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    • pp.105-109
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    • 2014
  • Plasmodium falciparum malaria is a major public health problem in Thailand due to the emergence of multidrug resistance. The understanding of genetic diversity of malaria parasites is essential for developing effective drugs and vaccines. The genetic diversity of the merozoite surface protein-1 (PfMSP-1) and merozoite surface protein-2 (PfMSP-2) genes was investigated in a total of 145 P. falciparum isolates collected from Mae Sot District, Tak Province, Thailand during 3 different periods (1997-1999, 2005-2007, and 2009-2010). Analysis of genetic polymorphisms was performed to track the evolution of genetic change of P. falciparum using PCR. Both individual genes and their combination patterns showed marked genetic diversity during the 3 study periods. The results strongly support that P. falciparum isolates in Thailand are markedly diverse and patterns changed with time. These 2 polymorphic genes could be used as molecular markers to detect multiple clone infections and differentiate recrudescence from reinfection in P. falciparum isolates in Thailand.

Rapid Topological Patterning of Poly(dimethylsiloxane) Microstructure (Poly(dimethylsiloxane) 미세 구조물의 신속한 기하학적 패터닝)

  • Kim, Bo-Yeol;Song, Hwan-Moon;Son, Young-A;Lee, Chang-Soo
    • Textile Coloration and Finishing
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    • v.20 no.1
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    • pp.8-15
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    • 2008
  • We presented the modified decal-transfer lithography (DTL) and light stamping lithography (LSL) as new powerful methods to generate patterns of poly(dimethylsiloxane) (PDMS) on the substrate. The microstructures of PDMS fabricated by covalent binding between PDMS and substrate had played as barrier to locally control wettability. The transfer mechanism of PDMS is cohesive mechanical failure (CMF) in DTL method. In the LSL method, the features of patterned PDMS are physically torn and transferred onto a substrate via UV-induced surface reaction that results in bonding between PDMS and substrate. Additionally we have exploited to generate the patterning of rhodamine B and quantum dots (QDs), which was accomplished by hydrophobic interaction between dyes and PDMS micropatterns. The topological analysis of micropatterning of PDMS were performed by atomic force microscopy (AFM), and the patterning of rhodamine B and quantum dots was clearly shown by optical and fluorescence microscope. Furthermore, it could be applied to surface guided flow patterns in microfluidic device because of control of surface wettability. The advantages of these methods are simple process, rapid transfer of PDMS, modulation of surface wettability, and control of various pattern size and shape. It may be applied to the fabrication of chemical sensor, display units, and microfluidic devices.

Image-based characterization of internal erosion around pipe in earth dam

  • Dong-Ju Kim;Samuel OIamide Aregbesola;Jong-Sub Lee;Hunhee Cho;Yong-Hoon Byun
    • Computers and Concrete
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    • v.33 no.5
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    • pp.481-496
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    • 2024
  • Internal erosion around pipes can lead to the failure of earth dams through various mechanisms. This study investigates the displacement patterns in earth dam models under three different failure modes due to internal erosion, using digital image correlation (DIC) methods. Three failure modes—erosion along a pipe (FM1), pipe leakage leading to soil erosion (FM2), and erosion in a pipe due to defects (FM3)—are analyzed using two- and three-dimensional image- processing techniques. The internal displacement of the cross-sectional area and the surface displacement of the downstream slope in the dam models are monitored using an image acquisition system. Physical model tests reveal that FM1 exhibits significant displacement on the upper surface of the downstream slope, FM2 shows focused displacement around the pipe defect, and FM3 demonstrates increased displacement on the upstream slope. The variations in internal and surface displacements with time depend on the segmented area and failure mode. Analyzing the relationships between internal and surface displacements using Pearson correlation coefficients reveals various displacement patterns for the segmented areas and failure modes. Therefore, the image-based characterization methods presented in this study may be useful for analyzing the displacement distribution and behavior of earth dams around pipes, and further, for understanding and predicting their failure mechanisms.

A Study on the Reflow Characteristics of Cu Thin Film (구리 박막의 Reflow 특성에 관한 연구)

  • Kim, Dong-Won;Gwon, In-Ho
    • Korean Journal of Materials Research
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    • v.9 no.2
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    • pp.124-131
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    • 1999
  • Copper film, which is expected to be used as interconnection material for 1 giga DRAM integrated circuits was deposited on hole and trench patterns by Metal Organic Chemical Vapor Deposition(MOCVD) method. After a reflow process, contact and L/S patterns were filled by copper and the characteristics of the Cu reflow process were investigated. When deposited Cu films were reflowed, grain growth and agglomeration of Cu have occurred in surfaces and inner parts of patterns as well as complete filling in patterns. Also Cu thin oxide layers were formed on the surface of Cu films reflowed in $O_2$ambient. Agglomeration and oxidation of Cu had bad influence on the electrical properties of Cu films especially, therefore, their removal and prevention were studied simultaneously. As a pattern size is decreased, preferential reflow takes place inside the patterns and this makes advantages in filling patterns of deep submicron size completely. With Cu reflow process, we could fill the patterns with the size of deep sub-micron and it is expected that Cu reflow process could meet the conditions of excellent interconnection for 1 giga DRAM device when it is combined with Cu MOCVD and CMP process.

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An Experimental Study on Injection Molding of Etched Surface Pattern (식각 표면패턴의 사출성형에 관한 실험적 연구)

  • Jing Chung Huang
    • Journal of the Korean Society for Precision Engineering
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    • v.20 no.2
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    • pp.25-32
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    • 2003
  • Molding properties of etched surface pattern are presented. Injection molding has given attention on improving dimensional accuracy and productivity. However, the molding of etched surface pattern on plastic parts is not researched relatively for its additional values, which can meet design function and customer's attraction. Specimens, whose surface patterns are made by print-type etching, are investigated. The molding properties of surface pattern are estimated with roughness deviation of surface pattern on part and mold. The etching properties are related to physical properties of plastic materials and surface roughness of etched pattern. Also, flow mark and gate location can give influence on surface pattern molding. The experimental result can contribute to good molding of surface pattern in injection molding.

A Study on the Mechanism of Arm Surface Changes for the development of Sleeve Drafting Standard (소매설계기준 개발을 위한 상지체표변화구조에 관한 연구)

  • 최해주
    • Journal of the Korean Society of Clothing and Textiles
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    • v.20 no.5
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    • pp.852-859
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    • 1996
  • The factors and mechanism of arm surface changes were analyzed by regression analysis for the relationship between changes in arm joint angle and arm surface changes, according to the direction of upper extremity motion. Body surface change patterns among subjects were tested also. Experiments were carried out on 3 female subjects of different body types to examine 26 motions in 4 directions for 4 upper extremity parts. The major conclusions of the study are as follows: 1. The expansion or contraction of arm surface length depends on the direction of upper extremity motion. 2. Arm surface length changes by linear expansion or contraction according to the joint angle of the direction of motion. The mechanism of arm surface changes is represented by a linear relation between arm surface changes and the (actors of the direction of upper extremity motion and arm joint angle. 3. Arm surface length shows the same pattern of body surface changes regardless of body type. A quantitative model of body surface changes at upper extremity should be developed for functional sleeve design.

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An Experimental Study on Injection Molding of Etched Surface Pattern (식각 표면패턴의 사출성형에 관한 실험적 연구)

  • 황금종;이희관;양균의
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2002.05a
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    • pp.583-586
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    • 2002
  • Molding properties of etched surface pattern are presented. Specimens, whose surface patterns are made by print-type etching, are investigated. The molding properties of surface pattern are estimated with roughness deviation of surface pattern on part and mold. The etching properties are related to physical properties of plastic materials and surface roughness of etched pattern. Also, flow mark and gate location can give influence on surface pattern molding. The experimental result can contribute to good molding of surface pattern in injection molding.

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Development of Sleeve Patterns of Structural Firefighting Protective Clothing using by 3D Body Shape and 3D Motion Analysis (3차원 인체형상과 3차원 동작분석에 의한 방화복 소매패턴 개발)

  • Han, Sul-Ah;Nam, Yun-Ja;Yoon, Hye-Jun;Lee, Sang-Hee;Kim, Hyun-Joo
    • Fashion & Textile Research Journal
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    • v.14 no.1
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    • pp.109-121
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    • 2012
  • This study aims at developing ergonomics patterns for the sleeve of structural firefighting protective clothing through 3D motion analysis in order to ensure efficiency and safety of firefighters who are exposed to harmful environment at work. A new research pattern was developed by applying the total results of 3D motion analysis, changes of body surface length measurements, and 2D data on 3D body shape analysis on the size 3 patterns of the existing coat sleeve. For the sleeves, we used the body surface length of the range of shoulder's flexion and the joint angle of the range of wrist's ulnar deviation. And for the production of structural firefighting protective clothing using the research pattern, we recruited a recognized producer of structural firefighting protective clothing designated by KFI. Unlike everyday clothes, structural firefighting protective clothing should be able to fully protect the wearers from the harmful environment that threatens their lives and should not cause any restrictions on their movement. Therefore, the focus of research and development of such protective clothing should be placed on consistent development of new technologies and production methods that will provide protection and comfort for the wearer rather than production cost reduction or operational efficiency. This study is meaningful as it applied 3D motion analysis instead of the existing methods to develop the patterns. In particular, since 3D motion analysis enables the measurement of the range of motion, there should be continuous research on the development of ergonomics patterns that consider workers' range of motion.