• 제목/요약/키워드: natural form

검색결과 2,381건 처리시간 0.036초

Solvent Dependence of Absorption and Fluorescence Spectra of Piroxicam. A Possible Intramolecular Proton Transfer in the Excited State

  • Yoon, Min-Joong;Choi, Hyong-Nae;Kwon, Hwang-Won;Park, Koon-Ha
    • Bulletin of the Korean Chemical Society
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    • 제9권3호
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    • pp.171-175
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    • 1988
  • The spectral properties of piroxicam in different solvents are similar to those of its skeletal precursor, HMBDC. The maximum absorption and emission wavelengths strongly depend on the hydrogen bonding ability of the solvent, and it is shown that intramolecular hydrogen bonding between the -OH and the ortho carbonyl group of the parent benzothiazine ring plays an important role in the solvent-dependence of their spectroscopic properties. The fluorescence spectra in aprotic nonpolar solvent exhibit abnormally large Stokes-shifted (${\sim}9,000cm^{-1}$) emission bands in contrast to the spectra in water. In ethanol, dual emission bands with two different fractional components of lifetimes have been observed. These results suggest that the abnormally red-shifted emission is attributed to the proton transferred form of an intramolecularly hydrogen-bonded closed conformer.

디젤 분사방식에 따른 이종연료 엔진의 성능 및 배기 분석 (Analysis on Performance and Emission with Different Diesel Injection Methods in a Dual-Fuel Engine)

  • 박현욱;이준순;오승묵;김창업;이용규;장형준
    • 한국분무공학회지
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    • 제27권2호
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    • pp.101-108
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    • 2022
  • Performance and emissions with different diesel injection methods were analyzed in a natural gas-diesel, dual-fuel engine under low-load conditions. Natural gas was supplied to intake port during the intake stoke to form a natural gas-air premixed mixture for all methods. Diesel was injected directly into the cylinder during the compression stroke in three ways: early injections, late injections, and a combination of early and late injections. The early injections had the highest thermal efficiency among the three methods owing to its highest combustion efficiency. The wide dispersion of diesel before the combustion initiation also allowed superior emissions characteristics.

현대 패션에 나타난 민속풍(Ethnic look)에 관한 연구 (A Study on Ethnic look Expressed in Modern Fashion)

  • 정연자
    • 대한가정학회지
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    • 제31권4호
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    • pp.215-229
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    • 1993
  • As a result of making an inquiry into the ethnic look of each region appearing in present-day fashion by Asia. America and Oceania. Africa and Europe as mentioned above, its characteristics could be summarized as follows: Firstly the Asian ethnic look consists of Indian, Chinese and Japanese looks as mainstream. In terms of form, the draped form constituted its mainstream, and both the draped form and the tunic form are appearing Simultaneously in the Chinese look. And in respect to color the Indian look is using luxurious primary colors red, blue, yellow and green and other regions are making overall use of natural colors. With respect to ornament various kinds of ornaments is utilized in Indian's Sari and turban. Chines's Coolie hat, straw hat and embroidery, knotted button, and bead ornament, and Japan's Obi and Obijime, etc. Secondly in America and Oceania, costurme representing the Indian look in North America and the picture of Western pioneer, and the Peruvian, Mexican and chilean ethnic looks in South America were expressing much. Here, the form consistied a draped form as its main strem, such colors as yellow, purple, grey, etc were much utilized, and the material of costume comprised knits, cotton and the like. And the ornament consisted of hats, tassel ornaments, bead ornaments, metal chain belt, long braided hair, etc. Thirdly, the African ethnic look had an exposing form and a draped form, and such colors as black, white, yellow, brown, etc were used as the fashion color. Ornaments such as precious stone, bead ornaments, animal bones, straw metal ornament, etc were used as fashion decorations. Fourthly, Russia's Cossack look, Bulgaria's Bavshika look, spain's ethnic look cane to the fore as the European look Both the draped form and the tunic form were used simultaneously as fashion form. And grey, brown, purple, etc were much used as fashion color in the European look. Such ornaments as Cossack. Bavshka, boots, tassel ornaments were much used and paisley pattern also was used.

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한.중 공동주택의 생활환경요인을 통한 단위평면 비교 연구 - 서울과 상하이 전통, 근대, 현대 공동주택 사례를 중심으로 - (A Comparative Study on the Apartment Unit Plans According to the Living Environment Elements of Housing in Korea and China - Focused on Apartment cases in Seoul and Shanghai -)

  • 양비;윤혜경;박현수
    • 한국실내디자인학회논문집
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    • 제19권2호
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    • pp.136-143
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    • 2010
  • This study aims to seek a direction of development in apartment interior planning method, considering residential condition and historical planning schemes in South Korea and China. In this study, South Korea and China's traditional housing and modern apartment unit was studied to identify environmental attributes of residence. For Korea, Banga, where upper class residents lived, and modern urban Hanok were chosen to be analyzed. For China, two types of housing wear studied: Sahapwon, original form of China housing, and Yinong house which is a typical Sanghai house. First, the elements of living environment in two major cities; Seoul and Sanghai was defined to analyze factors of traditional houses in both cities. Depending on those factors, relationship among traditional and modern housing types were compared and analyzed, focusing on unit plan case studies for a better understanding of living environment in South Korea and China. From this study, similarities and differences between apartment plans in Seoul and Shanghai was examined according to their residential style, surrounding natural environment and lifestyle factors. In Seoul's apartment, spacial composition and movement lines were mainly formed around the public space in Seoul, while public space of living and dining room was located at housing entrance area in the Shanghai's residential system, configuring narrow form of housing unit. In respect of the natural environment, the unit plan of rectangular form in Seoul was more efficient in day lighting and wind circulation than the unit plan of narrow form in Shanghai. It was also found that cultural differences of stand-up and seat life style influenced on the composition of unit plans in Seoul and Shanghai.n Apartment cases in Seoul and Shanghai.

자연유기체를 통한 산업제품 조형의 응용성에 대한 연구 - 제품디자인에 나타난 사례를 중심으로 - (A Study on the Application of Nature Organic Form for Industrial Products -Mainly around Examples of Product Design-)

  • 곽희준
    • 디자인학연구
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    • 제17권3호
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    • pp.91-100
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    • 2004
  • 자연은 끊임없이 신비한 산물들을 대량생산해내는 만물의 공장이며, 그 산물들은 끊임없이 변화하고 있다. 또한 자연은 인간이 살아가는 환경을 둘러싼 미적 아이디어를 끊임없이 제공한다. 그러므로 인간은 자연을 대상으로 시각적 관찰을 통해 표현하고자 하는 자연스런 충동에 따른 조형을 추구하게 된다. 자연에 대해 인간이 얻을 수 있는 미적 체험은 그 대상에 대하여 시각적으로 연구할 때, 연상에 따른 형상들을 의식적으로 떠올릴 수 있게 해주는 미학적 변형의 원천인 것이다. 수없이 변화된 자연물과 마찬가지로 의식적으로 경험되는 인 공의 산업 생산물은 자연물과 구조적, 형태적 질을 공유하며 조형적 균형을 위한 의미를 갖게 된다. 자연을 관찰하여 질서나 원리를 통해 디자인에 적용시키고자한 시도는 바우하우스 이후 디자인의 한 방법으로서 부분적으로 실천되어 왔지만, 자연에 대한 연구과정이 서로 분산된 영역에서 진행되어왔다. 최근에 이르러서 이러한 연구는 관련 분야간에 복합되는 입장에서 매우 중요시되고 있다. 따라서 자연유기체의 다양한 범주들을 본 연구에서는 단지 부분적으로 제품디자인 측면에서 고찰하지만, 종합적으로 디자인학적 조형성과 자연유기체의 조형학적 접근은 기본적으로 중요한 것이라 생각하여 본 소고에서 고찰해 보고자 한다.

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천연가스 유량 측정에서 헬름홀츠 자유에너지를 이용한 임계유동함수 계산 (Evaluation of Critical Flow Function by Using Helmholtz Free Energy for Natural Gas Flow Measurement)

  • 하영철;허재영
    • 대한기계학회논문집B
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    • 제37권12호
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    • pp.1167-1173
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    • 2013
  • 본 연구에서는 천연가스 유량 측정에서 2차 표준으로 사용되는 소닉노즐 뱅크 -12개 노즐 패키지로 구성-의 임계유동함수 계산 시간을 1초 이하로 단축하고자 하였다. 이를 위해 AGA 8-dc 상태방정식을 적용한 헬름홀츠 자유에너지를 유도하고 이로부터 적분 항이 없는 열역학 상태량 식을 도출하여 CFF 계산에 적용하였다. 그 결과 CFF 계산 시간이 기존 6.7초/12개에서 0.6초/12개로 크게 감소하는 것을 확인할 수 있었고 이 계산 시간은 가스 성분 수와 거의 무관함도 알 수 있었다. 또한 본 계산 결과의 정확도를 확인하기 위해 기존 CFF 국제비교연구의 결과와 비교한 결과 차이가 없음도 확인하였다.

Improvement of a Sulfolobus-E. coli Shuttle Vector for Heterologous Gene Expression in Sulfolobus acidocaldarius

  • Hwang, Sungmin;Choi, Kyoung-Hwa;Yoon, Naeun;Cha, Jaeho
    • Journal of Microbiology and Biotechnology
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    • 제25권2호
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    • pp.196-205
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    • 2015
  • A Sulfolobus-E. coli shuttle vector for an efficient expression of the target gene in S. acidocaldarius strain was constructed. The plasmid-based vector pSM21 and its derivative pSM21N were generated based on the pUC18 and Sulfolobus cryptic plasmid pRN1. They carried the S. solfataricus P2 pyrEF gene for the selection marker, a multiple cloning site (MCS) with C-terminal histidine tag, and a constitutive promoter of the S. acidocaldarius gdhA gene for strong expression of the target gene, as well as the pBR322 origin and ampicillin-resistant gene for E. coli propagation. The advantage of pSM21 over other Sulfolobus shuttle vectors is that it contains a MCS and a histidine tag for the simple and easy cloning of a target gene as well as one-step purification by histidine affinity chromatography. For successful expression of the foreign genes, two genes from archaeal origins (PH0193 and Ta0298) were cloned into pSM21N and the functional expression was examined by enzyme activity assay. The recombinant PH0193 was successfully expressed under the control of the gdhA promoter and purified from the cultures by His-tag affinity chromatography. The yield was approximately 1 mg of protein per liter of cultures. The enzyme activity measurements of PH0913 and Ta0298 revealed that both proteins were expressed as an active form in S. acidocaldarius. These results indicate that the pSM21N shuttle vector can be used for the functional expression of foreign archaeal genes that form insoluble aggregates in the E. coli system.

Adsorption Characteristics and Structure of 4,4'-Bis(mercaptomethyl)biphenyl on Silver by Surface-enhanced Raman Scattering and Density Functional Theory Calculations

  • Eom, So Young;Lee, Yu Ran;Kim, Hong Lae;Kwon, Chan Ho
    • Bulletin of the Korean Chemical Society
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    • 제35권3호
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    • pp.875-880
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    • 2014
  • Adsorption of 4,4'-bis(mercaptomethyl)biphenyl (44BMBP) on silver nanoparticles has been investigated by surface-enhanced Raman scattering (SERS) spectroscopy. In addition, the Raman spectra of 44BMBP in solid state and in basic condition have been obtained for comparative study to elicit the characteristics of adsorption. The observed Raman and SERS spectra were analyzed comparing with the normal modes and vibrational frequencies from density functional theory (DFT) calculations performed for the feasible structures of 44BMBP molecule. On the basis of excellent agreement between the calculated and the experimental results, the molecule is found to have both the cis- and trans-forms for the mercaptomethyl groups in the solid state as well as in the basic condition. In contrast, the molecule is found to be chemisorbed on the silver surface by forming two Ag-S linkages only in the cis-form but not in the trans-form due to the steric interruption, which indicates the parallel orientation of molecules on the surface. Particularly, the spectral features in the SERS spectra such as the absence of the C-H stretching band and enhancement for the out-of-plane skeletal modes are confirmatory for the parallel geometry through ${\pi}$ interaction between the phenyl rings and the metal surface, based on the electromagnetic surface selection rule.

Community Ecological Revaluation of Acer pseudosieboldianum and Carpinus cordata in the Natural Deciduous Forest

  • Kim, Ji Hong;Kang, Sung Kee;Lim, Seon Mi
    • Journal of Forest and Environmental Science
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    • 제32권1호
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    • pp.74-81
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    • 2016
  • Classified into sub-tree of the growth-form, Acer pseudosieboldianum and Carpinus cordata hardly reach the uppermost canopy with limited height growth potentiality in the natural deciduous forest. However, the two species usually dominate lower stories of the forest, playing an important role in overall ecological characteristics in the forest. Based on the vegetation data of 106 $20m{\times}20m$ sample plots in Mt. Jumbong area, this study was carried out to evaluate ecological constitution by several quantitative analysis so as to understand the mechanism of the natural deciduous forest. The results indicated that individuals of A. pseudosieboldianum and C. cordata were absent or few in overstory, but emerged the most dominant species in midstory and understory, providing adequate proof of the ecological importance. The comparison of indices of succession between presented and predicted values in midstory did not make much difference, suggesting that the species composition would not change much and come close to steady state in midstory and understory. The pair combination of species association noted that A. pseudosieboldianum had significant positive association with C. cordata, Quercus mongolica, and Tilia amurensis had significant positive association with A. pseudosieboldianum, A. pictum subsp. mono and Fraxinus mandshurica but negative association with F. rhynchophylla. Being compared with other major canopy tree species in the study forest, the target species of A. pseudosieboldianum and C. cordata had strong regeneration strategies, partially characterized by large number of saplings and pole sized trees and high ratio of live crown, which indicated high shade tolerance to survive in the limited amount of light under the canopy. Even though A. pseudosieboldianum and C. cordata do not reach and occupy the canopy layer mainly due to the inherent growth form, they would have highest competitive potentiality to prosper and dominate in the midstory of the natural deciduous forest.

Crystal Structure of Penicillin V Potassium Salt

  • Kim, Whan-Chul;Yi, Seung-Ho;Shin, Jung-Mi;Yoon, Tae-Sung
    • Bulletin of the Korean Chemical Society
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    • 제14권6호
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    • pp.713-717
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    • 1993
  • The crystal structure of the potassium salt of penicillin V has been studied by the X-ray crystallographic methods. Crystal data are as follows; potassium 3,3-dimethyl-7-oxo-6-phenoxyacetoamido-4-thia-1- azabicyclo[3.2.0]-heptane-2${\alpha}$-carboxylate, $K^+{\cdot}C_{16}H_{18}N_2O_5S^-$, $M_r$= 388.5, triclinic, Pl, a= 9.371 (1), b= 12.497 (2), c= 15.313 (2) ${\AA},\;{\alpha}= 93.74\;(2),\;{\beta}=99.32\;(1),\;{\gamma}=90.17\;(1)^{\circ},\;V=1765.7\;(2)\;{\AA}^3$, Z=4, $D_m=1.461\;gcm^{-1},\;{\lambda}(Cu\;K{\alpha})=1.5418\;{\AA},\;{\mu}=40.1\;cm^{-1}$, F(000)=808, T=296 K. The structure was solved by the heavy atom and difference Fourier methods with intensity data measured on an automated four-circle diffractometer. The structure was refined by the full-matrix least-squares method to a final R= 0.081 for 3563 observed $[I_0{\geq}2{\sigam}(I_0)]$ reflections. The four independent molecules assume different overall conformations with systematically different orientations of the phenyl groups although the penam moieties have the same closed conformations. There are intramolecular hydrogen bonds between the exocyclic amide nitrogen and phenoxy oxygen atoms. The penam moiety is conformationally very restricted although the carboxyl and exocyclic amide groups apparently have certain rotational degrees of freedom but the phenyl group is flexible about the ether bond despite the presence of the intramolecular N-H${\cdots}$O hydrogen bond. There are complicated pseudo symmetric relationships in the crystal lattice. The penam moieties are related by pseudo 20.5 screw axes and the phenyl groups by pseudo centers of symmetry. The potassium ions, related by both pseudo symmetries, form an infinite zigzag planar chain parallel to the b axis. Each potassium ion is coordinated to seven oxygen atoms in a severely distorted pentagonal bipyramid configuration, forming the infinite hydrophilic channels which in turn form the molecular stacks. Between these stacks, there are only lipophilic interactions involving the phenyl groups.