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Experimental Study on Flow Characteristic and Wave Type Flow at Downstream of Stepped Weir (계단형 보 하류 흐름특성과 Wave Type Flow에 관한 실험연구)

  • Kang, Joon-Gu;Yeo, Hong-Koo;Lee, Keum-Chan;Choi, Nam-Jeong
    • Journal of Korea Water Resources Association
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    • v.43 no.1
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    • pp.41-49
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    • 2010
  • Stepped weir of this study was suggested a type of natural type structures. Unique flow, such as Wave type flow, at downstream of mild slope stepped occurs. WTF(Wave type flow) is different with hydraulic jump occurred at Round crest weir. WTF is phenomenon to rise the water level by recirculation area occurred by step height at downstream of mild slope stepped. Wave height of WTF condition is higher than tailwater level and maximum velocity of WTF condition occurs in area of water surface. In this results, WTF presents to be important factor for design of join area of weir with levee. This study got and analyzed hydraulic condition occurred of WTF, scales of WTF and velocity profiles on flow patterns using experiments. WTF was not consider to stepped weir design and this results can be important data for design of stepped weir and structures.

Model Tests on the Lateral Behavior of Soldier Pile Type Breakwater Installed in Sand (모래지반에 설치된 가로널식 방파제의 횡방향 거동에 관한 모형실험)

  • Jang In-Sung;Lee Goo-Young;Kwon O-Soon;Park Woo-Sun;Jeong Weon-Mu;Kim Byoung-Il
    • Journal of the Korean Geotechnical Society
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    • v.21 no.1
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    • pp.29-41
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    • 2005
  • The small harbors and fishing ports in Korea have less economic efficiency if the previous construction method of breakwater would be utilized due to bad ground conditions in spite of low design waves. Therefore, it is necessary to develop a new type breakwater economically applicable to the cases with low design wave. In this study, a soldier pile type breakwater, which is found to be economic and can be easily constructed on the ground without any need of treatment of the ground, was newly introduced. The effects of embedded depth, reinforcement methods as well as pile types including saw type and flat type on the lateral behavior of the proposed breakwaters installed in loose sandy soils were investigated from model test. The test results revealed that the lateral resistance increases by increasing the embedded depth and by adopting the reinforcement techniques such as raker and anchor. Furthermore, it was also verified that the saw type breakwater shows better geotechnical performance than the flat type breakwater.

Recent Advances in Structural Studies of Antifreeze Proteins (구조 생물학을 이용한 Antifreeze protein의 최근 연구동향)

  • Lee, Jun-Hyuck;Lee, Sung-Gu;Kim, Hak-Jun
    • Ocean and Polar Research
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    • v.33 no.2
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    • pp.159-169
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    • 2011
  • Antifreeze proteins (AFPs) have ice binding affinity, depress freezing temperature and inhibit ice recystallization which protect cellular membranes in polar organisms. Recent structural studies of antifreeze proteins have significantly expanded our understanding of the structure-function relationship and ice crystal growth inhibition. Although AFPs (Type I-IV AFP from fish, insect AFP and Plant AFP) have completely different fold and no sequence homology, they share a common feature of their surface area for ice binding property. The conserved ice-binding sites are relatively flat and hydrophobic. For example, Type I AFP has an amphipathic, single ${\alpha}$-helix and has regularly spaced Thr-Ala residues which make direct interaction with oxygen atoms of ice crystals. Unlike Type I AFP, Type II and III AFP are compact globular proteins that contain a flat ice-binding patch on the surface. Type II and Type III AFP show a remarkable structural similarity with the sugar binding lectin protein and C-terminal domain of sialic acid synthase, respectively. Type IV is assumed to form a four-helix bundle which has sequence similarity with apolipoprotein. The results of our modeling suggest an ice-binding induced structural change of Type IV AFP. Insect AFP has ${\beta}$-helical structure with a regular array of Thr-X-Thr motif. Threonine residues of each Thr-X-Thr motif fit well into the ice crystal lattice and provide a good surface-surface complementarity. This review focuses on the structural characteristics and details of the ice-binding mechanism of antifreeze proteins.

A Study on the Management System and the Facility Type of Mental Health and Welfare Center in Japan (1) (일본 정신보건복지센터의 운영체계 및 시설유형 분석연구 (1))

  • Lim, Yenjung;Chai, Choul-Gyun
    • Journal of The Korea Institute of Healthcare Architecture
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    • v.20 no.4
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    • pp.57-65
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    • 2014
  • Purpose : Mental health service desire has been diversified according to the increase of economic level and rapid social change. Mental Health and Welfare Center(MHWC) is a provider of mental health services in Japan. This is a basic stage study which will suggest the architectural planning guidelines for MHWC. Methods : Data were collected through literature research, field surveys, and expert interviews to 69 MHWC in Japan. 1) Research for the policy and legal aspects of mental health support system. 2) Research for structural aspects of MHWC: Characteristics of establishment, management, and regional factors. 3) Research for the physical environment aspects of MHWC: Classification and evaluation of MHWC's Type by locational characteristics in Japan. Results : The result of this study can be summarized into three points. The first one, Mental Health and Welfare Center's service has being expanded to suicide, depression and stress from chronic mental illness, to reflect social needs. The second one, The average population of area installed at Mental Health and Welfare Center was 2,307,570 person, and average area of the regions were $5,745m^2$. The third one, Mental Health and Welfare Center is divided into single-structure type and combine-structure type. And combine-structure type is divided into medical-combine type, welfare-combine type, and public-combine type.

Stress Analysis of Total Knee System Depending on Implant Materials and Fixation Methods (인공무릎관절에 있어서 임플란트의 재료 및 고정방법에 따른 응력분석)

  • Cho, C.H.;Cho, Y.K.;Choi, J.B.;Choi, K.
    • Proceedings of the KOSOMBE Conference
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    • v.1997 no.11
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    • pp.484-488
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    • 1997
  • Three-dimensional finite element analyses were used to compare the stress distribution and the stability of the fixation among seven different tibial components and to investigate the effect due to implant materials in total knee arthroplasty. The components included an intact tibia(Type I), Cemented Cobalt-Chromium tibial tray implanted with a PMMA cemented Co-Cr stem(Type II), Cemented Co-Cr tibial tray with a uncemented Co-Cr stem(Type III), Cemented Ultra High Molecular Weight Polyethylene (UHMWPE) tibial tray with a cemented UHMWPE stem (Type IV), Cemented UHMWPE tray with a uncemented UHMWPE stem(Type V), Cemented Co-Cr tray without a stem(Type VI), and Cemented UHMWPE tray without a stem(Type VII). Uncemented components were assumed to have complete bony in growth and a rigid state of fixation between component and bone. The interface between bone/cement/component of cemented components was also assumed to be fully bonded. Bi-condylar forces were applied. The results indicated that Uncemented stem components provided lower bone stress shielding and stress concentration. The UHMWPE tray and stem component showed better agreement with the intact tibia than the Co-Cr Alloy tray and stem components. If the implant tray can be fixed firmed without a stem, Cemented PE tray without a stem(Type VII) may be recommended to give the best characteristics in the sense of stress distribution and stability.

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A study on surface roughness depending on cutting direction and cutting fluid type during micro-milling on STAVAX steel (STAVAX 강의 마이크로 밀링 중 가공 방향 및 절삭유체 분사형태에 따른 표면 거칠기 경향에 관한 연구)

  • Dong-Won Lee;Hyeon-Hwa Lee;Jin Soo Kim;Jong-Su Kim
    • Design & Manufacturing
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    • v.17 no.2
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    • pp.22-26
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    • 2023
  • As Light-Emitting Diodes(LEDs) continue to advance in performance, their application in automotive lamps is increasing. Automotive LEDs utilize light guides not only for aesthetics but also to control light quantity and direction. Light guides employ patterns of a few hundred micrometers(㎛) to regulate the light, and the surface roughness(Ra) of these patterns can reach tens of nanometers(nm). Given that these light guides are produced through injection molding, mold processing technology with high surface quality micro-patterns is required. This study serves as a preliminary investigation into the development of high surface quality micro-pattern processing technology. It examines the surface roughness of the workpiece based on the cutting direction of the pattern and the cutting fluid type when cutting micro-patterns on STAVAX steel using cubic Boron Nitride(cBN) tools. The experiments involved machining a step-shaped micro-pattern with a height of 60 ㎛ and a pitch of 400 ㎛ in a 22×22 mm area under identical cutting conditions, with only the cutting direction and cutting fluid type being varied. The machining results of four cases were compared, encompassing two cases of cutting direction(parallel to the pattern, orthogonal to the pattern) and two cases of cutting fluid type (flood, mist). Consequently, the Ra value was found to be the highest(Ra 128.33 nm) when machining with the flood type in parallel to the pattern, while it was the lowest(Ra 95.22 nm) when machining with the mist type orthogonal to the pattern. These findings confirm that there is a difference of up to 25.8 % in the Ra value depending on the cutting direction and cutting fluid type.

The Old Women Prostitutes Serving the Old Men: A Research on the Actual Condition of 'Bacchus Azumma' and the Basic-Setting of the Elderly Counseling Process (노인을 대상으로 하는 성매매 피해 여성 연구: '박카스 아줌마' 실태 조사 및 노인상담적 접근)

  • Lee, Ho Sun
    • 한국노년학
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    • v.31 no.3
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    • pp.489-503
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    • 2011
  • The purpose of this paper is to explore the actual condition of the old women prostitutes serving the old men (so-called 'Bacchus Azumma') in qualitative research and to suggest the elderly counseling process for the old women prostitutes. For this, 10 old women prostitutes, aged 53~71, were interviewed as research participants. The data obtained through the depth interviews were analyzed using a qualitative analytic method. As a result, four types of the old women prostitutes according to prostitution inducing forms and motives are found: Inducing-Living type, Re-inducing-Living type, Re-inducing-Playing type, Re-inducing-Forced type. It is essential for each traumatized prostitute to be treated according the degrees of their trauma(PTSD) in the elderly counseling.