• Title/Summary/Keyword: Asymmetric flux

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A study on expression methods for structural aesthetics in modern fashion design - Focus on the architectural characteristics of Santiago Calatrava - (현대 구조적 패션디자인에 나타난 구조미의 표현방식에 대한 연구 - 산티아고 칼라뜨라바의 건축특성을 중심으로 -)

  • Lee, Yeonji;Um, Sohee
    • The Research Journal of the Costume Culture
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    • v.23 no.5
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    • pp.737-754
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    • 2015
  • The structural aesthetics of architecture are becoming an inspirational source for many fashion designers and have been reborn in structural fashion. This study planned to analyze the method of expression of structural aesthetics expressed in modern structural fashion design and the construction method to maximize such an effect on the basis of the construction characteristic of Santiago Calatrava as the representative architect of the structural aesthetic. According to the study, the structural aesthetics expressed in modern structural fashion design are as follows: 1) The symbolical formative aesthetic expressed by symbolical inference and analyzation; 2) the dynamic beauty of physic expressed by visual emphasis and dynamics; and 3) the asymmetric beauty of symmetry expressed by metastasis toward the boundary between balance and imbalance. In addition, to maximize structural aesthetics, we used repetition and a progressive technique based on rhythm, asymmetry, and incision-based variances, such as balance, polygon flux, and inference, and analyzation-based distortion as the structuring principle. The following expression methods for maximizing structural aesthetics were found: 1) symbolical and structural exaggeration of appearance; 2) detail technique expansion and material property diversification; and 3) the three-dimensional transformation of structure and shell expression. Structural fashion design was found to have maximized structural aesthetics by using such expression methods to secure artistic esthetics, destroy existing shapes and patterns, and create unique shapes.

Effect of Toluene Added to Casting Solution on Characteristic of Phase Inversion Polysulfone Membrane (상전환 공정에 의한 폴리설폰막의 제조에 있어 제막용액에 첨가된 톨루엔의 영향)

  • Choi, Seung-Rag;Park, So-Jin;Seo, Bum-Kyoung;Lee, Kune Woo;Han, Myeong-Jin
    • Applied Chemistry for Engineering
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    • v.19 no.6
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    • pp.633-639
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    • 2008
  • Polysulfone membranes were prepared via the phase inversion process. Toluene was added as a nonsolvent additive in the casting solution containing a mixture of polysulfone and n-methylpyrrolidone. When prepared via the diffusion-induced process using isopropanol as a precipitation nonsolvent, the solidified membranes revealed a similar asymmetric structure irrespective of the addition of toluene, presenting both a dense skin layer and a sponge-like support layer. The added toluene played a role of enhancing liquid-liquid phase separation of the casting solution, and skin layer thickness of a prepared membrane increased with toluene content in the casting solution. On membrane performance, the solute rejection showed a uniform behavior irrespective of the addition of toluene. However, in spite of the significant increase in dense skin layer thickness, the water permeation through the membrane prepared with 60 wt% toluene revealed five times as much flux, compared with that of the membrane prepared without toluene additive.

Preparation of Organic-inorganic Hybrid PES Membranes using Fe(II) Clathrochelate (Fe(II) clathrochelate을 이용한 유.무기 PES 복합막의 제조)

  • Jung, Bo Ram;Son, Yeji;Lee, Yong Taek;Kim, Nowon
    • Membrane Journal
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    • v.23 no.1
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    • pp.80-91
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    • 2013
  • Metal-templated condensation of cyclohexanedione dioxime and phenylboronic acid in the presence of Fe(II) sulfate heptahydrate proceeds cleanly in methanol to furnish the Fe(II) clathrochelate. An organic/inorganic hybrid membranes composed of Fe(II) clathrochelate and polyethersulfone was prepared by using phase inversion method. For membrane preparation, the Fe(II) clathrochelate was highly soluble (3~5 g/L) in DMF, NMP, and DMAc, which meets the requirements for the solubility of metal complexes in polar aprotic solvent used in membrane preparation. It was stable even in the presence of strong acids, such as trifluorosactic acid (pKa = 0.3). It was characterized by UV-vis spectroscopy, and their stability in solution phase studied in the presence of (i) strong acids or (ii) competing chelates. Organic/inorganic hybrid membranes were prepared with polyethersulfone, polyvinylpyrrolidone, p-toluenesulfonic acid, Fe(II) clathrochelate and DMF by using nonsolvent induced phase inversion method. The addition of Fe(II) clathrochelate leads increase of surface pore density, mean pore size and flux. We can obtain highly asymmetric membranes by addition of Fe(II) clathrochelate.

Study on the Pervaporation Characteristic of Water-alcohol Mixtures through Aromatic Polyetherimide Membranes : I. Pervaporation through Structure Change of Symmetric Dense and Asymmetric Structure Membranes (방향계 폴리에테르이미드막의 물-알콜 혼합액의 투과증발 특성에 관한 연구 : I.구조 변화에 따른 투과증발)

  • Kim, S.G.;Jegal, J.G.;Lee, K.-H.
    • Applied Chemistry for Engineering
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    • v.8 no.6
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    • pp.945-953
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    • 1997
  • Aromatic polyetherimide membranes were prepared by dry/wet phase inversion method and investigated regarding the pervaporation characteristic of water-alcohol mixtures by using the permselective property of imide group and the structure modification of skin layer of the membrane. The membrane selectivity increased with the reaction time of surface-modification, to some extent, and the density of top layer tends to increases with increasing the reaction time. In the case of dense membrane, the separation factor was 160 and 2000 for 90wt% ethanol mixture and 90wt% isopropanol solution, respectively, which implies that aromatic polyetherimide has a high permselectivity. The temperature dependence of permeation flux seems to follow an Arrhenius type at the temperature range of ($40^{\circ}C-70^{\circ}C$).

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Insertion Mutation in HMG-CoA Lyase Increases the Production Yield of MPA through Agrobacterium tumefaciens-Mediated Transformation

  • Dong, Yuguo;Zhang, Jian;Xu, Rui;Lv, Xinxin;Wang, Lihua;Sun, Aiyou;Wei, Dongzhi
    • Journal of Microbiology and Biotechnology
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    • v.26 no.11
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    • pp.1924-1932
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    • 2016
  • Mycophenolic acid (MPA) is an antibiotic produced by Penicillium brevicompactum. MPA has antifungal, antineoplastic, and immunosuppressive functions, among others. ${\beta}-Hydroxy-{\beta}-methylglutaryl-CoA$ (HMG-CoA) lyase is a key enzyme in the bypass metabolic pathway. The inhibitory activity of HMG-CoA lyase increases the MPA biosynthetic flux by reducing the generation of by-products. In this study, we cloned the P. brevicompactum HMG-CoA lyase gene using the thermal asymmetric interlaced polymerase chain reaction and gene walking technology. Agrobacterium tumefaciens-mediated transformation (ATMT) was used to insert a mutated HMG-CoA lyase gene into P. brevicompactum. Successful insertion of the HMG-CoA lyase gene was confirmed by hygromycin screening, PCR, Southern blot analysis, and enzyme content assay. The maximum MPA production by transformants was 2.94 g/l. This was 71% higher than wild-type ATCC 16024. Our results demonstrate that ATMT may be an alternative practical genetic tool for directional transformation of P. brevicompactum.

A Study on Water Uptake Behavior and Properties of Pervaporation PVA Membrane (투과증발 PVA 분리막의 물 흡수 거동 및 물성 연구)

  • 김광제;박인준;김동권;이수복
    • Membrane Journal
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    • v.5 no.2
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    • pp.74-80
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    • 1995
  • Asymmetric poly(vinyl alcohol) (PVA) membranes were prepared by varying the precipitation conditions of the phase inversion technique, and the influences of precipitation conditions on the water uptake of the membrane were investigate. The degree of water uptake of the membrane increased and reached a certain maximum value, as the precipitation time increased. However, it decreded after that. As the precipition temperauure became lower, the degree of water uptake increased more or less. The addition of a nonionic surfactant to the precipitaon solution was effective reducing the precipitation time by lowering the surface tension of the precipitation solution, but ig didn't change the maximum value of its own degree of water uptake. In addition, the relationship between the degree of water uptake and the separation characteristics and mechanical properies of the membrane were investigated. The selectivity factor of the membrane for pervaperation separation decreased, but the permeate flux increased, respectively, with increasing the degree of water uptake. The tensile strength and elongation of the membrane, respectively, increased to a maximum value with increasing the degree of water uptake, and then decreased abtuptly.

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Initial Rotor Polarity Detection of Single-phase Permanent Magnet Synchronous Motor Based on Virtual dq-axis (단상 영구자석 동기 전동기의 가상 dq축 기반 초기 회전자 자극 검출)

  • Seo, Sung-Woo;Hwang, Seon-Hwan;Lee, Ki-Chang
    • Journal of IKEEE
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    • v.24 no.4
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    • pp.1004-1010
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    • 2020
  • This paper proposes an initial rotor magnetic pole detection method for single-phase permanent magnet synchronous motors. The target motor cannot obtain position information based on the back emf in the low speed and stop state. Therefore, an open loop starting process is required, and in this process, initial rotor position information for low current and soft start is need. The proposed initial rotor magnetic pole detection algorithm considers the effect of asymmetric air- gap and magnetic flux. In addition, the high-frequency voltage signal injection and the offset voltage for accurate detection is used. As a result, the permanent magnet poles are is determined by acquiring the maximum value of the induced current using the virtual dq-axis.