• Title/Summary/Keyword: UD

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Cure Shrinkage Behavior of Polymer Matrix Composite according to Degree of Cure (경화도에 따른 고분자 기지 복합재의 경화 수축률 거동)

  • Kwon, Hyuk;Hwang, Seong-Soon;Choi, Won-Jong;Lee, Jae-Hwan;Kim, Jae-Hak
    • Composites Research
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    • v.27 no.3
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    • pp.90-95
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    • 2014
  • Cure shrinkage during cure process of polymer matrix composites develope residual stress that cause some structural deformation, such as spring-in, spring-out and warpage. The carbon/epoxy prepreg used in this study is Hexply M21EV/34%/UD268NFS/IMA-12K supplied by Hexcel corp. Cure shrinkage and degree of cure measured by TMA(thermomechanical analyzer) and DSC(differential scanning calorimetry). Cure shrinkages are measured by TMA within a temperature range of $140{\sim}240^{\circ}C$ in a nitrogen atmosphere, and degree of cure determined by the heat of reaction using dynamic and isothermal DSC runs in argon atmosphere. As a result, the cure shrinkage is increased dramatically in a degree of cure range between 27~80%. the higher the cure temperature, the lower the degree of cure occurring to begin cure shrinkage.

Development of Compressive Failure Strength for Composite Laminate Using Regression Analysis Method (회귀분석법에 의한 복합재료 적층판의 압축파손강도 개발)

  • Lee, Myoung Keon;Lee, Jeong Won;Yoon, Dong Hyun;Kim, Jae Hoon
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.40 no.10
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    • pp.907-911
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    • 2016
  • This paper provides the compressive failure strength value of composite laminate developed by using regression analysis method. Composite material in this document is a Carbon/Epoxy unidirection(UD) tape prepreg(Cycom G40-800/5276-1) cured at $350^{\circ}F(177^{\circ}C$). The operating temperature is -$-60^{\circ}F{\sim}+200^{\circ}F$($-55^{\circ}C{\sim}+95^{\circ}C$). A total of 56 compression tests were conducted on specimens from eight (8) distinct laminates that were laid up by standard angle layers ($0^{\circ}$, $+45^{\circ}$, $-45^{\circ}$ and $90^{\circ}$). The ASTM-D-6484 standard was used for test method. The regression analysis was performed with the response variable being the laminate ultimate fracture strength and the regressor variables being two ply orientations ($0^{\circ}$ and ${\pm}45^{\circ}$).

A Study of Carbon NCF Prepreg Manufacturing and Stacking Pattern Optimal Design Using Structure Analysis (CFRP 적용을 위한 Carbon NCF Prepreg 제작 및 구조해석을 활용한 적층패턴 최적설계 연구)

  • Kim, S.;Shin, H.C.;Ha, Sung Kyu
    • Composites Research
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    • v.33 no.1
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    • pp.13-18
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    • 2020
  • Recently, the fire rescue truck in problem proceed research it for the fast works action and for pass the small road. So we were research for weight reduction. In this study, the (NO. 5) fifth boom of the fire rescue truck have 288 mm(W) × 299 mm(D) × 3,691 mm(L) with a maximum load of 876 kg and the thickness of 3 mm of the Steel Boom. This changing of Steel (STRENX960) to CFRP was weave Carbon Fiber NCF (±45°, 2axis) and then it make the NCF Prepreg. This process was designed based on structural analysis, the effects of NCF Prepreg (±45°) on torsion were identified, and the optimal design was made with Stacking Pattern (b). Stack patterns were optimized for levels equal or higher than existing Steel Boom and CFRP Boom stacked in the UD direction, and finally, the lightening effect on weight of approximately 49.6% of the steel was identified.

Metabolism of Pyrimidine Deoxyribonucleosides and Heat-resistivity of CdR-aminohydrolase in the Mouse Small Intestine (생쥐 小腸에서의 Pyrimidine Deoxyribonucleoside 代謝와 CdR-aminohydrolase의 熱抵抗性)

  • Kang, Man-Sik;Rhee, Juong-Gile;Cho, Joong-Myung
    • The Korean Journal of Zoology
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    • v.17 no.3
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    • pp.107-116
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    • 1974
  • The metabolism of CdR-2-$^14 C$ and UdR-2-$^14 C$ in mouse small intestine has been studied in connection with the effect of heat treatment on the enzymes concerned in vitro. CdR-2-$^14 C$ is deaminated reaidly by CdR-aminohydrolase at nucleoside level and then degraded into U by the action of nucleosidase which is quite resistant to cleave N-pentose bond of cytosine nucleosides, CdR and CR. High inactivation temperature of $80^\\circC$ was observed for CdR-aminohydrolase, while nucleosidase has an inactivation temperature of $60^\\circC$. CdR-aminohydrolases in various tissues of mouse were inactivated at $80^\\circC$, but not one in tissues of rabbit. It might be assumed that there are correlations between order specificity and inactivation temperature of the enzyme. A physiological significance of the appearance of CdR-aminohydrolase in differentiated tissues of mammals possibly be regarded as a main function in catabolic pathways.

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Development of Green Building Certification Framework for Urban Neighborhood Scale Development (근린단위 녹색건축인증 평가체계 개발)

  • Jung, Seunghyun
    • The Journal of the Korea Contents Association
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    • v.19 no.12
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    • pp.203-214
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    • 2019
  • Green building certification is being implemented in various countries around the world for the purpose of securing sustainability and reducing energy use and carbon emissions. Korea has been implementing G-SEED, a green building certification, for buildings since 2002, but in foreign countries, the evaluation target has been expanded from buildings to neighborhood units, cities, and infrastructure. Therefore, the purpose of this study was to establish Korean green building certification system in terms of neighborhood scale. In order to make Korean certification scheme for neighborhood communities, three major international certification systems (BREEAM Communities, LEED-ND, and CASBEE-UD) were compared. Comparison was executed about definitions and goals, certification system and range, certification categories, and regulation relationship by literature review. Based on the results, the evaluation system proposal including the scope, subjects, and items for green building certification in Korea was proposed.

The change of dental clinic name (치과의원 상호명의 시대적 변화)

  • Yu, Su-Been;Song, Bong-Gyu;Yang, Byoung-Eun
    • The Journal of the Korean dental association
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    • v.56 no.12
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    • pp.658-666
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    • 2018
  • This study analyzes 21,686 dental clinic business names from 1946 to February 2016, where official records exist. The results of this study will be used as a historical data of Korean dental clinic and contribute to the decision of dental clinic name. According to the results of analysis, the first official dental clinic used in Korea was 'Chu' in 1946, 'Minsaeng' and 'Chusaeng' in 1958, and "Won" in 1959. In the 1960s, dentists' family names were often used as dental clinics. In the 1970s, dental clinic names were often used as dentists' family name, 'Jung-ang' and 'Seongsin'. In the 1980s, dental clinic name was used more than other names such as 'Seoul', 'Yonsei', 'Hyundai' and 'Sang-a' along with the dentist's family name. In the 1990s, a dental clinic name was used to refer to the words 'Yeonsei', 'Seoul', 'Hyundai', 'Sang-a', 'Isalang', 'Uli', 'Jeil', 'Bubu' used a lot. In the 2000s, Dental Clinic's name began to use english words such as $^{\circ}{\AE}Good$ Morning','White','Prime 'and adjectives such as 'Haengboghan', 'Ipyeonhan'. The characteristic of the dental clinic name in 2010 is the increase of the business name 'UD'. From 1946 to February 2016, the most commonly used dental clinic name was 'Seoul', 'Uri', 'Isarang', 'Yonsei', 'Hyundai', 'Good Morning' 'Jung-ang', 'UD', 'I', 'Miso'.

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A Study on the Universal Design for Public Sports Facilities to Promote Daily Life Sports of the Persons with Disabilities - Focused on the Public Sports Facilities in Seoul (장애인 생활체육 활성화 방안으로서 공공생활 체육시설의 유니버설디자인 적용에 관한 연구 - 서울시 공공생활체육시설을 중심으로)

  • Ha Chun;Bea Yoongho
    • Journal of The Korea Institute of Healthcare Architecture
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    • v.29 no.2
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    • pp.27-37
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    • 2023
  • Purpose: Sports activities for life are an opportunity to fulfill the basic desire to be healthy and participate in society of the individual level, and it is also the realization of the trend of living together with persons without disabilities and persons with disabilities at the level of social inclusion. I try to propose to improve sports participation of persons with disabilities from the point of view of 'Universal Design.' Methods: Firstly, analysing of previous studies which to classify the barrier free certification standards to universal design's 7 principles and which to investigate public sports facilities. Secondly, reanalyzing, based on UD 7 principles, the raw data of the research results of public sports facilities in Seoul. Thirdly. then, I suggest the improvement plan to promote public sports facilities for all the people including persons with disabilities. Results: The results of this study are that although the facilities have the basic accessibility, there were some inconveniences in using the facility for the elderly and the disabled. So I suggest a few method to improve the public sports facilities from the perspective of universal design : 1) Needs to expand 'Bandabi Sports Center' as a sports facilities for sports activities for life of all of people, 2) Needs to improve accessibility of existing public sports facilities and to raise awareness for the persons with disabilities and universal design, 3) Needs to produce 'UD guidelines' for the sports facilities.

Manufacturing Technology and Evaluation for X-ray Transmission Performance of CT Cradle composed of Sandwich Composites (샌드위치 복합재로 구성된 CT(Computed Tomography) 장비 Cradle 제작기술 및 X선 투과성능 평가)

  • Lee, Sang-Jin;Kim, Jong-Chul;Kim, Min-Woo;Park, Ja-Yeon
    • Composites Research
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    • v.22 no.6
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    • pp.13-17
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    • 2009
  • This paper decided the 3D shape of sandwich composite for the cradle of CT instrument, suggested the stacking sequence with satisfaction on structural criteria using the Finite Element Analysis, and introduced the manufacturing method to meet the X-ray transmission performance uniformly. The design of Cradle was considered the space between other parts, fixing method, and assembly condition with headrest part. It is decided the stacking sequence to meet the criteria that the deflection at the end point is less than 20 mm when it is applied to 135 kg load at the specific locations. In site of manufacturing method, at first, it is used the hand lay-up for carbon UD and carbon fabric/polyester resin, but it had the ununiform X-ray transmission performance due to the void and excess resin. For solving this problem, it was replaced with the infusion method for the first layer of face material and the application of carbon UD or fabric/epoxy resin prepreg for other layers. Therefor, the property of X-ray transmission was improved.

Effects of Ulmus davidiana Planch(Ulmaceae) on mineralization, bone morphogenetic protein-2, alkaline phosphatase, type I collagen and collagennase-1 in bone cells (유근피가 골세포의 mineralization, bone morphogenetic protein-2, alkaline phosphatase, type I collagen 및 collagennase-1에 미치는 영향)

  • Byun, You-seok;Yoon, Jong-hwa;Hwang, Min-seob;Kim, Kap-sung;Jo, Hyun-seog
    • Journal of Acupuncture Research
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    • v.22 no.3
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    • pp.13-22
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    • 2005
  • By extracting the sample of Ulmus davidiana Planch(Ulmaceae), which was known to have the protection of damaged organ and the anti-inflammation action, it was experimented whether it is available for the application of treatment of osteoporosis. In the previous experiment, the extracts from Ulmus davidiana Planch(Ulmaceae) were confirmed to inhibit Cathepsin K through treating the cell of long bone, which contains osteoclast. Through this, it is suggested that Ulmus davidiana Planch(Ulmaceae) can play a role of prodrug as an inhibitor of absorbing bone ash in the treatment of osteoporosis. In the present experiment, a research in vitro Ulmus davidiana Planch(Ulmaceae) on the growth and sensibilization of osteoblast in a state that induced osteosis by using the cell tissue of MC3T3-El pre-osteoblastic was conducted. As a result, it could be confirmed that Ulmus davidiana Planch(Ulmaceae) has the strengthening function by enhancing the dosage and the activity of ALP depending on the time. The dosage was observed at the minimum of $50{\mu}g/m{\ell}$ and the maximum of $150{\mu}g/m{\ell}$. The enhancement in bone morphogenetic protein-2 at $100{\mu}g/m{\ell}$ UD could be observed, and it also increased the concentration of ALP mRNA within the cell of MC3T3-El. At $60{\mu}g/m{\ell}$ UD which indicated a little increase in Type I collagen mRNA for a long time of culture. However, it was shown to sharply inhibit the expression of gene in the culture between 15-20 days. These results suggest that Ulmus davidiana Planch(Ulmaceae) has an influence upon bone metabolism through thje sensibilization of osteoblast. Therefore, it could be known that utilized Ulmus davidiana Planch(Ulmaceae) can be positively applied for the general disease of bone metabolism through future studies.

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Estimation of Genetic Parameter for Milk Production and Linear Type Traits in Holstein Dairy Cattle in Korea (국내 Holstein 젖소의 유생산 형질과 유방 및 지제 선형심사 형질에 대한 유전모수 추정)

  • Won, J.I.;Dang, C.K.;Lim, H.J.;Jung, Y.S.;Im, S.K.;Yoon, H.B.
    • Journal of agriculture & life science
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    • v.50 no.1
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    • pp.167-178
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    • 2016
  • This study was conducted to estimate genetic parameters for milk production and linear type traits in Holstein dairy cattle in Korea. The data including milk yields, fat yields, protein yields, fat percent, protein percent, somatic score and 15 linear type traits for 10,218 first parity cows collected by Dairy Cattle Improvement Center, National Agricultural Cooperative, Korea, which were calving from January 2009 to April 2013. Genetic and error (co)variances between two traits selected form 19 traits were estimated using bi-trait pairwise analyses with WOMBAT package. The estimated heritabilities for milk yield(MY), fat yield(FY), protein yield(PY), fat percent(FP), protein percent(PP), somatic cell score(SCS), udder depth(UD), udder texture(UT), median suspensory(MS), fore udder attachment(FUA), front teat placement (FTP), rear attachment height(RAH), rear attachment width(RAW), rear teat placement(RTP), front teat length(FTL), foot angle(FA), heel depth(HD), bone quality(BQ), rear legs side view(RLSV), rear legs rear view(RLRV) and locomotion(LC) were 0.128, 0.144, 0.100, 0.273, 0.333, 0.090, 0.179, 0.066, 0.104, 0.109, 0.127, 0.099, 0.059, 0.069, 0.154, 0.014, 0.010, 0.052, 0.065, 0.175 and 0.031, respectively. Among the genetic correlations, UD, UT, FTP, RAW, FTL, FA and RLSV with MY were -0.334, 0.271, 0.445, 0.544, 0.076, -0.281 and -0.228, respectively, and MS, FTP, RTP, FTL, FA, BQ, RLSV, RLRV and LC with PP were -0.147, -0.182, -0.262, -0.136, 0.355, 0.311, 0.135, 0.233 and 0.143, respectively. Especially, MY had the highest positive genetic correlation with RAW (0.544), while SCS had the highest negative genetic correlation with LC (-0.603). FP had negative genetic correlation with most udder traits, whereas, FP had positive genetic correlation with leg and hoof traits (0.056 - 0.355).