• 제목/요약/키워드: end cap

검색결과 94건 처리시간 0.025초

Ethynyl 말단기를 갖는 Polyisoimide 올리고머의 합성 및 이들의 경화거동에 관한 연구 (Synthesis and Curing Behaviors of Polyisoimide Oligomers with Ethynyl End Groups)

  • 최석우;김보옥;김지흥;남성우;전붕수;김영준
    • 폴리머
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    • 제38권6호
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    • pp.774-781
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    • 2014
  • 4-ethynylaniline(4-EA) 혹은 4-phenylethynyl phthalic anhydride(4-PEPA)을 end-capper로 사용하여 분자량이 2500 g/mol 혹은 5000 g/mol로 조절되고, 반응성 ethynyl 기를 갖는 4,4'-diamino diphenyl ether(4,4'-ODA)/3,3',4,4'-benzophenone tetracarboxylic acid dianhydride(BTDA), 4,4'-ODA/4,4'-oxydiphthalic anhydride(ODPA)계 폴리아이소이미드 올리고머를 합성하여 이들의 중합 및 경화거동을 연구하였다. FTIR 분광분석을 통하여 이들 폴리아이소이미드 올리고머 말단에 반응성 ethynyl 기가 포함되어 있음을 확인할 수 있었다. 이미드화 반응은 폴리아이소이미드 올리고머의 화학구조에도 영향을 받을 뿐 아니라 올리고머의 분자량에도 영향을 받아 분자량 2500 g/mol 올리고머가 5000 g/mol 올리고머보다 대략 $10^{\circ}C$ 정도 낮은 온도에서 이미드화 반응이 일어났다. Ethynyl기의 가교반응은 이미드화 반응보다 높은 온도에서 일어났으며 4-EA로 end-cap된 폴리아이소이미드 올리고머에 대해서는 이 두 반응이 DSC 그래프에서 겹쳐서 나타났다. 4-PEPA로 end-cap된 4,4'-ODA/ODPA 폴리아이소이미드 올리고머에 대해 등 속도 가열 DSC 실험을 통해 이미드화 반응 및 가교반응에 대한 활성화 에너지와 지수앞인자를 구하였다. 이미드화 반응에 대한 활성화 에너지는 141 kJ/mol, 지수앞인자 값은 $1.45{\times}10^{13}min^{-1}$, 가교반응에 대한 활성화 에너지는 177 kJ/mol, 지수앞인자 값은 $2.90{\times}10^{13}min^{-1}$이 얻어졌다.

콘크리트충전 강관 합성보의 계면거동 (Interface Behavior of Concrete Infilled Steel Tube Composite Beam)

  • 이용학;이타;정종현;김형주;박건태
    • 한국구조물진단유지관리공학회 논문집
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    • 제18권5호
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    • pp.9-18
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    • 2014
  • 본 논문은 강-콘크리트 슬립실험으로 결정된 계면 계수값을 휨 하중을 받는 콘크리트 충전강관 합성보 실험의 결과예측에 적용하여 콘크리트 충전강관 합성보의 계면거동과 구속효과를 규명하였다. 원형단면의 콘크리트가 전단면압축을 받도록 하기 위해서 콘크리트 충전강관에 웨브와 플랜지를 추가한 콘크리트 충전강관 합성보를 사용하여 휨 거동실험을 수행하였다. 콘크리트가 전단면 압축을 받는 단부가 개방된 콘크리트 충전합성강관의 경우에는 구속효과에 의해 약 16%의 강도증진효과를 확인하였으며, 단부를 폐쇄하여 구속효과가 커진 콘크리트충전 합성강관의 경우에는 35% 정도의 큰 강도증진효과가 발생하는 것을 확인하였다. 실험과 수치해석을 통해 얻은 이러한 결과는 콘크리트 충전강관을 이용한 교량의 상부 거더나 아치리브에 대한 단면 결정에 적용되는 적용성을 갖는다.

PVC and POM gripping mechanisms for tension testing of FRP bars

  • Basaran, Bogachan;Yaka, Harun;Kalkan, Ilker
    • Structural Engineering and Mechanics
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    • 제77권1호
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    • pp.75-87
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    • 2021
  • The present study pertains to the introduction of two new types of grip adaptor for universal testing machines, namely Polyvinyl Chloride (PVC) and Polyoxymethylene (POM) grip adaptors, and their application to tension testing of FRP bars with different fiber and surface finish types. The tabs are connected to the FRP bar sample with the help of mechanical anchors, i.e. bolts. These new adaptors offer vital superiorities over the existing end tab designs (anchors with filling material or mechanical anchorage), including the reduction in the time and labor for production, reusability and the mild nature, i.e. low hardness of the tab material, which retards and even prevents peeling and crushing in the gripping regions of an FRP sample. The methods were successfully applied to FRP bars with different types of fiber (CFRP, GFRP and BFRP) and different types of surface texture (ribbed, wrapped, sand-coated and wound). The test results indicated that the both types of end caps prevented slip of the bar, crushing and peeling in the gripping zone. The mechanical properties from the material tests with the new caps were in perfect agreement with the ones from the material tests with steel tubular caps.

PHC 에너지파일의 열응력에 따른 축하중-침하 수치해석 (Numerical Analysis of Thermal Effect on Axial Load and Pile Settlements in PHC Energy Piles)

  • 이대수;민혜선;임현성;정상섬
    • 한국지반공학회논문집
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    • 제29권5호
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    • pp.5-17
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    • 2013
  • 본 논문에서는 열응력에 따른 PHC 에너지파일의 축하중과 침하량의 변화를 수치해석을 통하여 분석하였다. 이를 위해 $3{\times}3$, $5{\times}5$ 배열 군말뚝 형태의 에너지파일을 말뚝 간격과 배치, 지반조건, 말뚝의 선단지지조건 및 말뚝 캡의 강성도 등의 조건으로 구분하여 수치해석을 수행하였다. 본 연구 결과 말뚝 중심 간격이 클수록 온도변화에 따른 말뚝의 축하중 차이가 크게 나타났고, 사질토지반이 점성토지반 보다 온도변화에 의한 침하량의 변화가 크게 나타났다. 또한, 에너지파일이 모서리부에 위치할 때 말뚝의 축하중 차이가 가장 크게 나타났으며, 말뚝의 선단이 암반에 지지된 경우 온도변화에 의한 축하중 변화가 더 크게 발생하여 침하량이 감소하는 것을 확인하였다. 말뚝 캡의 강성도에 대한 영향은 말뚝 캡의 강성이 커질수록 온도변화에 의한 침하량이 감소하는 것으로 나타났다.

종합슈퍼마켓의 소비자들의 구매경향별 POP광고반응에 관한 연구 (A study on the P.O.P response for the buying trends of General Supermarket)

  • 김태성;김판진
    • 유통과학연구
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    • 제8권1호
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    • pp.35-42
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    • 2010
  • 본 연구는 종합슈퍼마켓에서 소비자 구매경향별 구매시점광고(POP)에 대한 반응과 POP를 접한 후 최종 구매단계에서의 중요 의사결정 요인과의 관계를 규명하기 위한 연구이다. 본 연구결과를 살펴보면 첫째, 종합슈퍼의 POP광고반응 중 소비자들은 엔드켑(End Cap)에 대한 반응점수가 높은 것으로 나타났으며, 둘째는 성별 충동적 구매경향에 대한 차이는 전반적으로 남성이 여성보다 높았다. 또한, 구매경향 간, 변수들 간의 상관관계를 살펴본 결과 충동적 구매와 비계획적 구매경향(r=.325), 충동적 구매경향과 즉각적 구매경향(r=.249)에서 상관관계가 있는 것으로 나타났다.(p<0.01) 본 연구 결과 소비자의 소비패턴도 점점 합리성 추구하며 계획적 쇼핑과 더불어 소비에 있어 POP 광고가 자신의 합리성 또는 계획성을 촉진시키는 요인이 되었을 때 POP 광고가 비로소 소비로 연결될 수 있다는 연구결과를 도출하였다.

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Development of an RNA Expression Platform Controlled by Viral Internal Ribosome Entry Sites

  • Ko, Hae Li;Park, Hyo-Jung;Kim, Jihye;Kim, Ha;Youn, Hyewon;Nam, Jae-Hwan
    • Journal of Microbiology and Biotechnology
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    • 제29권1호
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    • pp.127-140
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    • 2019
  • Since 1990, many nucleic acid expression platforms consisting of DNA or RNA have been developed. However, although RNA expression platforms have been relatively neglected, several such platforms capped at the 5' end of RNA by an anti-reverse cap analog have now been developed. At the same time, the capping reaction is a bottleneck in the production of such platforms, with high cost and low efficiency. Here, we investigated several viral and eukaryotic internal ribosome entry sites (IRESs) to develop an optimal RNA expression platform, because IRES-dependent translation does not require a capping step. RNA expression platforms constructed with IRESs from the 5' untranslated regions of the encephalomyocarditis virus (EMCV) and the intergenic region of the cricket paralysis virus (CrPV) showed sufficient expression efficiency compared with cap-dependent RNA expression platforms. However, eukaryotic IRESs exhibited a lower viral IRES expression efficiency. Interestingly, the addition of a poly(A) sequence to the 5' end of the coxsackievirus B3 (CVB3) IRES (pMA-CVB3) increased the expression level compared with the CVB3 IRES without poly(A) (pCVB3). Therefore, we developed two multiexpression platforms (termed pMA-CVB3-EMCV and pCrPV-EMCV) by combining the IRESs of CVB3, CrPV, and EMCV in a single-RNA backbone. The pMA-CVB3-EMCV-derived RNA platform showed the highest expression level. Moreover, it clearly exhibited expression in mouse muscles in vivo. These RNA expression platforms prepared using viral IRESs will be useful in developing potential RNA-based prophylactic or therapeutic vaccines, because they have better expression efficiency and do not need a capping step.

스키타이계(係) 복식(服飾)에 대(對)한 연구(硏究) (A study on the Scythian costume)

  • 김문자
    • 패션비즈니스
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    • 제11권4호
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    • pp.204-220
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    • 2007
  • The background of Korean Ethnical Costume was originated from those northern mounted nomadic groups, which was Scythe style Costume Culture. Through the antique records and paintings of tombs bequests hereby describe the forms of Scythian Cotume (1) Headgear : There was Conical Cap(or Pointed Cap), Feathered Cap, and Crown. (2) Clothes : Both Men and Women wore Jacket as upper garment with leftsided collars, narrow sleeves to the length of the hip line. As lower garment, they wore the tight Trousers and Kungo(:窮袴)that was attached with gusset. (3) Belts and Boots : On the upper garment bound the leather Belts that was hanged a hook that was shaped of animal form at the end. Scythian Buckles was divided into six groups, animal-shaped, animal's head shaped, animal fight-shaped, rectangle-shaped, rectangle openwork-shaped, genre scene shaped Buckle. To the Boots, they wore leather boots. (4) Ornaments : Ornaments divided into Dress Trimming(:Gold plaques), Earrings, Necklaces(;Torques), Bracelets, Rings. Scythian Gold Plaques were divided into several types according to the shape, animal style(curved beast shape, profile shape, head reversed over its back shape), round shape, quadrilateral form, star shape, flower shape, crescent shape, bundle shape, human appearance. Earrings consisted of a plain ring and pendant ring was a middle ornament hung from it to a pendants which hung was made of heart shaped leaves of the tree, beads-linked. Scythian Torques were divided into several types according to the shape, Torque with Terminal style, Spiral style, Layers style, Crescent-shaped pectoral style, Crown style. Scythian Bracelet were divided into 4 styles according to the shape, Bracelets with ends shaped like beasts style, Spiral style, Layers style, Crown with openwork style. Rings were rhomb-shaped and animal shaped styleRings (5) Animal motifs used in Scythian ornaments appears that in some cases the work was intended to be purely ornamental, while many times the motifs had symbolic meaning (such as the successful dominance of the aggressor over the victim portrayed in the attack scenes). Magical use of symbols may have been inten-ded to guarantee the power of the aggressor.

프랑스 <마카이요프스키 성경(Maciejowski Bible)>의 중세복식 표현에 관한 연구 (A Study on the Middle Age Costume Expression of France )

  • 김희정
    • 복식문화연구
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    • 제16권2호
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    • pp.263-277
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    • 2008
  • In picture bible, the picture is helpful for showing story more vividly and specifically and it is helpful for finding the meaning of bible hidden behind familiarity. It plays the role of the most powerful testimony and expression, with which human provides himself. The purpose of study was to grasp the relation among historical background of the middle age, human's characteristic and symbolic color by considering the fact that the costume expressed in Maciejowski Bible, which is a picture bible of the middle age and observing type, color and decoration of costume. Among 46 folios organizing Maciejowski Bible, 129 pictures explaining the Book of Genesis, the Book of Exodus, the Book of Leviticus, the Book of Numbers, the Book of Deuteronomy, the Book of Joshua and the Book of Judges, which belong to the former 400 years of the old Testament, were analyzed for people's costumes. The pictures shown in Maciejowski Bible portrays object, costume and behavior on the background of France of the 13th century so we can find out the precious natures of middle age's costume, weapon and armor. Especially, the portrait about finger armor of chain mail attached in hauberk becomes the outstanding evidence that can encroach the discussion over whether it was used in the end of 1300s. Regarding costumes of main characters, they wore chemise and braies as underwear, wore tunic or cotte having various lengths from the length reaching knee to the length reaching 8round as basic costume and wore mantle with different-colored lining and hose with various colors. In the war picture, we can see hauberk made with chain mail and cyclas with long slit, which was worn over hauberk, barrel helmet, norman helmet and steel school cap. Regarding cap. man usually wore coif, beret, shade-shaped cap, straw hat and woman wore the decoration using veil and hairlace and used the method to wrap whole hair with net. As the colors used in the costume of the picture bible, scarlet, blue, green and brown were usually used in order. They usually wore costumes decorated splendidly with the colors haying hish brightness and chroma.

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Post-transcriptional and post-translational regulation during mouse oocyte maturation

  • Kang, Min-Kook;Han, Seung-Jin
    • BMB Reports
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    • 제44권3호
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    • pp.147-157
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    • 2011
  • The meiotic process from the primordial stage to zygote in female germ cells is mainly adjusted by post-transcriptional regulation of pre-existing maternal mRNA and post-translational modification of proteins. Several key proteins such as the cell cycle regulator, Cdk1/cyclin B, are post-translationally modified for precise control of meiotic progression. The second messenger (cAMP), kinases (PKA, Akt, MAPK, Aurora A, CaMK II, etc), phosphatases (Cdc25, Cdc14), and other proteins (G-protein coupled receptor, phosphodiesterase) are directly or indirectly involved in this process. Many proteins, such as CPEB, maskin, eIF4E, eIF4G, 4E-BP, and 4E-T, post-transcriptionally regulate mRNA via binding to the cap structure at the 5' end of mRNA or its 3' untranslated region (UTR) to generate a closed-loop structure. The 3' UTR of the transcript is also implicated in post-transcriptional regulation through an association with proteins such as CPEB, CPSF, GLD-2, PARN, and Dazl to modulate poly(A) tail length. RNA interfering is a new regulatory mechanism of the amount of mRNA in the mouse oocyte. This review summarizes information about post-transcriptional and post-translational regulation during mouse oocyte meiotic maturation.