• Title/Summary/Keyword: molecular attractions

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The Influence of Dielectric Constant on Ionic and Non-polar Interactions

  • Hwang, Kae-Jung;Nam, Ky-Youb;Kim, Jung-Sup;Cho, Kwang-Hwi;Kong, Seong-Gon;No, Kyoung-Tai
    • Bulletin of the Korean Chemical Society
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    • v.24 no.1
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    • pp.55-59
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    • 2003
  • This work is focused on analyzing ion-pair interactions and showing the effect of solvent induced inter-atomic attractions in various dielectric environments. To estimate the stability of ion-pairs, SCI-PCM ab initio MO calculations were carried out. We show that the solvent-induced attraction or ‘cavitation' energy of the ion-pair interactions in solution that arises mainly from the stabilization of the water molecules by the generation of an electrostatic field. In fact, even the strong electrostatic interaction characteristic of ion-pair interactions in the gas phase cannot overcome the destabilization or reorganization of the water molecules around solute cavities that arise from cancellation of the electrostatic field. The solvent environment, possibly supplemented by some specific solvent molecules, may help place the solute molecule in a cavity whose surroundings are characterized by an infinite polarizable dielectric medium. This behavior suggests that hydrophobic residues at a protein surface could easily contact the side chains of other nearby residues through the solvent environment, instead of by direct intra-molecular interactions.

Time Dependence of the Rheological Properties of the Solutions of Polyacrylontrile and Acrylonitrile-Itaconic Acid Copolymer in Dimethyl sulfoxide (아크릴 중합체 및 아크릴-이타코닉산 공중합체/ 디메틸술폭시드 용액의 유변학적 특성의 시간의존성)

  • 이남순
    • Textile Coloration and Finishing
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    • v.13 no.6
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    • pp.435-440
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    • 2001
  • This study investigates the rheological properties of in-situ polymerized solutions of polyacrylonitrile(PAN) and acrylonitrile(AN) -itaconic acid(IA) in dimethyl sulfoxide(DMSO) in terms of temperature, concentration, and time. The complex viscosity and storage modulus of the solutions were generally increased with elapsing time, which is ascribable to the three-dimensional pseudostructures formed by strong inter- or Intra-molecular attractions through Polar -CN and -COOH groups. The three-dimensional pseudonetworks would lead to relation of the acrylic solutions in long term. This was more noticeable at higher temperature within the temperature range examined. In the case of 20% solutions one can not observe lower Newtonian flow region in the viscosity curve. Disappearance of lower Newtonian flow region is indicative of heterogeneity of the solution system. Casson Plot of the viscosity data revealed that 20% solutions of PAN and AN-IA copolymer in DMSO clearly demonstrated positive yield stress, ascertaining formation of pseudostructures in the solution systems.

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Time Dependence of the Rheological Properties of the Solutions of Polyacrylontrile and Acrylonitrile-Itaconic Acid Copolymer in Dimethyl sulfoxide (아크릴 중합체 및 아크릴-이타코닉산 공중합체/디메틸술폭시드 용액의 유변학적 특성의 시간의존성)

  • Lee, Nam Sun
    • Textile Coloration and Finishing
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    • v.13 no.6
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    • pp.77-77
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    • 2001
  • This study investigates the rheological properties of in-situ polymerized solutions of polyacrylonitrile(PAN) and acrylonitrile(AN)-itaconic acid(IA) in dimethyl sulfoxide(DMSO) in terms of temperature, concentration, and time. The complex viscosity and storage modulus of the solutions were generally increased with elapsing time, which is ascribable to the three-dimensional pseudostructures formed by strong inter- or intra-molecular attractions through Polar -CN and -COOH groups. The three-dimensional pseudonetworks would lead to gelation of the acrylic solutions in long term. This was more noticeable at higher temperature within the temperature range examined. In the case of 20% solutions one can not observe lower Newtonian flow region in the viscosity curve. Disappearance of lower Newtonian flow region is indicative of heterogeneity of the solution system. Casson Plot of the viscosity data revealed that 20% solutions of PAN and AN-IA copolymer in DMSO clearly demonstrated positive yield stress, ascertaining formation of pseudostructures in the solution systems.

The Interaction Potential Functions in an Electrolyte Protein Solution

  • Jee, Nam-Yong;Kim, Jae-Jun
    • Macromolecular Research
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    • v.14 no.6
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    • pp.654-658
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    • 2006
  • Recent developments in equations of state for molecular fluids have demonstrated the feasibility of using the hard-sphere equation to describe the effects of repulsive forces in simple fluids. By including a suitable term for attractive forces, most conveniently a uniform background potential, the properties of bio-macromolecular interaction can be roughly calculated. However, the choice of the potential used in perturbed hard-sphere chain (PHSC) theory for describing the attractions between macromolecules is rather complicated. For hard-sphere chains, the prediction accuracy from each model strongly depends on the choice of potential function.

Molecular Linker Enhanced Assembly of CdSe/ZnS Core-Shell Quantum Dots (분자 끈을 활용한 CdSe/ZnS 양자 점의 향상된 배열)

  • Cho, Geun Tae;Lee, Jong Hyeon;Nam, Hye Jin;Jung, Duk Young
    • Korean Chemical Engineering Research
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    • v.46 no.6
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    • pp.1081-1086
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    • 2008
  • QDs-LEDs(quantum dot light emitting device) should contain well-organized arrays of QDs on an electron transport layer. Thin films of CdSe/ZnS core-shell QDs were successfully fabricated on $TiO_2$ substrates by using PDMS stamp and micro contact printing method. 2-Carboxyethylphosphonic acid(CAPO) and 1,6-hexanedithiol(HDT) were employed as molecular linkers in assembling CdSe/ZnS core-shell QDs with high-density and uniform array. The CAPO increased the binding strength between the QDs and the substrates, and the HDT induced the strong inter-particle attractions of assembled QDs. The assembling properties of QDs thin films were characterized by SEM, AFM, optical microscope and photoluminescence spectroscope(PL).

Haraldiophyllum hawaiiense sp. nov. (Delesseriaceae, Rhodophyta): a new mesophotic genus record for the Hawaiian Islands

  • Paiano, Monica O.;Huisman, John M.;Cabrera, Feresa P.;Spalding, Heather L.;Kosaki, Randall K.;Sherwood, Alison R.
    • ALGAE
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    • v.35 no.4
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    • pp.337-347
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    • 2020
  • Haraldiophyllum hawaiiense sp. nov. is described as a new mesophotic alga and a new genus record for the Hawaiian Islands. Six specimens were collected at a depth range of 81-93 m from Papahānaumokuākea Marine National Monument, and their morphology investigated, as well as molecular phylogenetic analyses of the plastidial ribulose-1,5-bisphosphate carboxylase-oxygenase large-subunit (rbcL) gene and a concatenated alignment of rbcL and nuclear large-subunit rRNA gene (LSU) sequences. Phylogenetic analyses supported H. hawaiiense sp. nov. as a distinct lineage within the genus Haraldiophyllum, and sister to a large clade containing the type species, H. bonnemaisonii, as well as H. crispatum and an undescribed European specimen. The six Hawaiian specimens were shown to be identical, but unique among other species of the genus as well as the recently segregated genus Neoharaldiophyllum, which comprises half of the species previously included in Haraldiophyllum. The vegetative morphology of H. hawaiiense sp. nov. resembles Neoharaldiophyllum udoense (formerly H. udoensis); however, no female or post-fertilization structures were found in the Hawaiian specimens to allow a more comprehensive comparison. The molecular phylogenies demonstrate that Haraldiophyllum is paraphyletic, suggesting either that the Myriogrammeae tribe includes undescribed genera, including Haraldiophyllum sensu stricto, or that Neoharaldiophyllum species should be transferred into the genus Haraldiophyllum. However, based on vegetative morphology and molecular analyses, and pending resolution of this taxonomic issue, the Hawaiian specimens are placed within the genus Haraldiophyllum. This new record for the Hawaiian Islands highlights the novel biodiversity from mesophotic depths, reaffirming the need for further investigation into the biodiversity of Mesophotic Coral Ecosystems.

Theory of Capillarity of Laplace and birth of Mathematical physics (라플라스 모세관이론과 수학물리학의 태동)

  • Lee, Ho-Joong
    • Journal for History of Mathematics
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    • v.21 no.3
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    • pp.1-30
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    • 2008
  • The success of Newton's Gravitational Theory has influenced the theory of capillarity, beginning in the early nineteenth century, by providing a major model of molecular attraction. He used the equation of the attraction of spheroids, which is expressed by second order partial differential equations, to utilize this analogy as the same kind of a particle's force, between gravitational, refractive force of light, and capillarity. The solution of the differential equation corresponds to the geometrical figure of the vessel and the contact angle which is made by the fluid. Unknown abstract functions $\varphi(f)$ represent interaction forces between molecules, giving their potential functions. By conducting several kinds of experimental conditions, it was found that the height of the ascending fluid in the tube is inversely proportional to the rayon of the tube or the distance of the plate. This model is an essential element in the theory of capillarity. Laplace has brought Newtonian mechanics to completion, which relates to the standard model of gravitational theory. Laplace-Young's equation of capillarity is applicable to minimal surfaces in mathematics, to surface tensional phenomena in physics, and to soap bubble experiments.

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A Study on Development of Experimental Contents Using 3-channel Multi-Image Playback Technique: Based on transparent OLED and dual layer display system (3채널 멀티 영상 재생 기법과 증강현실을 이용한 체험 콘텐츠 제작에 관한 연구: 투명 OLED 및 듀얼 레이어 디스플레이 시스템 기반)

  • Lee, Sang-Hyun
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.17 no.6
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    • pp.151-160
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    • 2017
  • Among the methods of developing tourist spots and culture as the experience contents, it is a common method to display high-quality video images on a large display, and it is necessary to make a special difference between the participant's active participation and the visual experience in other regions. In this paper, using the single molecular OLED and active type, the regional tourist spots blend transparent OLED dual-layer display systems with the extended image implementation and augmented interaction techniques to give the participants a real-world experience, such as directing to new experiences and beautiful sights. In this paper, additional images and UI layers are applied to the layers of the images to allow visitors to experience sightseeing information, weather, maps, accommodations, festivals and photo materials with image. In addition to the dual-layer system, it also added a multi-display system that additionally has one vertical 55-inch display on each side, adding to the experience the immersive experience and interface interlocking fun. By using transparent OLED, dual layer panel and 3-channel Multi-image playback technique, the augmented type experience contents which can experience the local attractions in Jeollanamdo province in Korea at all time without any limitation of time and space were developed.