• Title/Summary/Keyword: End cap

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

  • Choi, Seok Woo;Kim, Bo Ock;Kim, Ji-Heung;Nam, Sung Woo;Jeon, Boong Soo;Kim, Young Jun
    • Polymer(Korea)
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    • v.38 no.6
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    • pp.774-781
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    • 2014
  • Acetylenic or phenylethynyl end-capped polyisoimide oligomers ($M_w$ 2500 g/mol, 5000 g/mol) based upon 4,4'-diamino diphenyl ether (4,4'-ODA)/4,4'-oxydiphthalic anhydride (ODPA) and 4,4'-ODA/3,3',4,4'-benzophenone tetracarboxylic acid dianhydride (BTDA) were synthesized by using 4-ethynylaniline (4-EA) or 4-phenylethynyl phthalic anhydride (4-PEPA) as an end capper. The incorporation of ethynyl groups were confirmed by FTIR spectroscopy. The isomerization temperature was influenced by molecular weight as well as the backbone structure of polyisoimides oligomers. Thus, polyisoimide oligomers with molecular weight of 2500 g/mol was found to be imidized at temperature $10^{\circ}C$ lower than that for the oligomers with molecular weight of 5000 g/mol. The crosslinking reaction of ethynyl groups occurred at a higher temperature than that for the isoimide/imide isomerization reaction. These two reactions were totally or partially overlapped on the DSC thermograms for the polyisoimide oligomer end-capped with 4-EA. Kinetics of thermal imidization and crosslinking reactions for the 4,4'-ODA/ODPA polyisoimide oligomers end-capped with 4-PEPA were investigated by performing dynamic DSC experiments at heating rate of $10^{\circ}C/min$. The activation energy and pre-exponential factors were 141 kJ/mol and $1.45{\times}10^{13}min^{-1}$ for the imidization reaction and 177 kJ/mol and $2.90{\times}10^{13}min^{-1}$ for the crosslinking reaction, respectively.

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

  • Lee, Yong-Hak;Lee, Ta;Jeong, Jong-Hyeon;Kim, Hyeong-Ju;Park, Kun-Tae
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.18 no.5
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    • pp.9-18
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    • 2014
  • Interface behavior and confining effects of concrete-infilled steel tube (CFT) composite beam were investigate based on the experimental observations and numerical analyses. For this purpose, laboratory four-points bending tests were performed for the two test specimens of 1,000mm long CFT composite beams. The test beams were made of ${\phi}110mm$ and 4.5mm thick steel tube and 10mm thick steel web and bottom flange. Therefore, concrete infilled in steel tube was in compression through the entire cross section due to the web and bottom flange. Two end section conditions, with end section cap and without end section cap, were considered in experiments to monitor the relative slip displacement at ends and induce confining effects at center. In numerical aspects, finite element analysis considering steel-concrete interface behavior was performed and compared to the experimental results.

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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    • v.77 no.1
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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.

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

  • Lee, Dae-Soo;Min, Hye-Sun;Lim, Hyun-Sung;Jeong, Sang-Seom
    • Journal of the Korean Geotechnical Society
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    • v.29 no.5
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    • pp.5-17
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    • 2013
  • This study investigates the effect of thermal stress on axial load and pile settlement of PHC energy piles. A series of numerical analyses were performed by controlling major influencing parameters such as pile arrangement, pile spacing, end-bearing condition, soil condition and pile cap stiffness. It is found that the characteristics of pile-load transfer are significantly affected by seasonal operation mode (i.e., cooling and heating) throughout the year. Also, the axial load under thermal loading increases with increasing the pile spacing. The settlement of the pile in sand is larger than that in clay because of the thermal stress generated. It is also found that thermal stress highly influences on the end-bearing pile, corner pile and rigidity of pile cap.

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

  • Kim, Tae-Sung;Kim, Pan-Jin
    • Journal of Distribution Science
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    • v.8 no.1
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    • pp.35-42
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    • 2010
  • This study is for finding out the relationship between reactions on POP per consumer purchase trends and major factor for making final purchasing decisions after being exposed to POP from large supermarkets. The following results were obtained after the research. First, consumers displayed higher reaction scores on End-Cap in general among POP advertisements. The factors for making final purchase decision are in the order of function > price > brand for household electrical goods, price > design > function for sundry goods and design > price > function for clothing (including bedding). Second, the results of analyzing the differences based on age on impulsive purchase showed that the lower the age the higher the tendency. Unplanned purchase trend also showed higher when younger. The results of this study showed that there are discrepancies in the theory related with existing POP advertisements, that is, the theory that impulsive purchasers have higher POP responses.

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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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    • v.29 no.1
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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.

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

  • Kim, Moon-Ja
    • Journal of Fashion Business
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    • v.11 no.4
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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.

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

  • Kim, Hee-Jung
    • The Research Journal of the Costume Culture
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    • v.16 no.2
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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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    • v.44 no.3
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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.