• 제목/요약/키워드: Hydrogen bonding

검색결과 671건 처리시간 0.033초

Effects of Stock Characteristics on Paper Bulk

  • Lee, Jin-Ho;Park, Jong-Moon
    • 한국펄프종이공학회:학술대회논문집
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    • 한국펄프종이공학회 2006년도 PAN PACIFIC CONFERENCE vol.2
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    • pp.423-426
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    • 2006
  • Paper has fibers and fines network structure and it is strongly affected by interface bonding between fibers. Depending on the inter-fiber bonding, paper bulk is determined. Fines play an important roll in Campbell and consolidation effect through wet pressing and drying operations. Refined Sw-BKP, Hw-BKP and BCTMP fines were used to investigate the fines effect. Wet-web strength, breaking length, scattering coefficient, and hydrodynamic specific volume were measured. According to the result of experiments, chemical and morphological compositions of fines do not strongly affect to wet-web forming, but strongly affect to drying operations which form hydrogen bonding among fiber-fines-fiber matrixes. Paper bulk should be controlled by the extent of hydrogen bonding between fibers during drying operations.

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Temperature Dependent Self-Diffusion Coefficients of Valinomycin and the Potassium-Valinomycin Complex

  • Kim, Su-Deuk;Lee, Yun-Jung;Joo, Hyun-Hye;Ahn, Sang-Doo
    • 한국자기공명학회논문지
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    • 제12권1호
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    • pp.51-59
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    • 2008
  • Convection effect in liquids has been one of the main targets to be overcome in pulsed-field-gradient NMR measurements of self-diffusion coefficients since the temperature gradient along the sample tube generated by the heating and/or cooling process causes the effect, resulting in additional diffusion. It is known that the capillary is the most appropriate tube type for diffusion experiments at variable temperatures since the narrower tube suppresses convection effectively. For evaluating the properties of hydrogen bonding, diffusion coefficients of the $K^+$-complexed and free valinomycin in a micro tube have been determined at various temperatures. From the analysis of the obtained diffusion coefficient values, we could conclude that the intramolecular hydrogen bonding in both of the $K^+$ complexed and free valinomycin in a non-polar solvent is preserved over the observed temperature range, and the temperature dependence of hydrogen bonding is more pronounced in free valinomycin. It is also thought that there is no big change in the radius of the $K^+$-complexed as temperature is varied, and the ratio of overall radius, $r_{complex}/r_{free}$ is slightly decreased as temperature rises.

(第2報) 2-Chloro-1-Propanol 에 關하여 ((Part 2) 2-Chloro-1-Propanol)

  • 김호징;김순경
    • 대한화학회지
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    • 제5권1호
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    • pp.52-55
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    • 1961
  • Assuming an intramolecular hydrogen-bonding, computation has been made on the optical rotatory power of 2-Chloro-1-Propanol. The magnitude of the calculated rotation is in fair agreement with the measured value of Lucas (calculated value: 21.6. measured value: 17.39). The agreement supports the validity of the assumption concerning the hydrogen-bonding between O atom and Cl atom. The agreement in sign confirms the validity the Fischer projection formula given by Lucas.

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A New Empirical Potential Function and Its Application to Hydrogen Bonding

  • Kang, Young-Kee;Jhon, Mu-Shik
    • Bulletin of the Korean Chemical Society
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    • 제2권1호
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    • pp.8-11
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    • 1981
  • A new potential function based on spectroscopic results for diatomic molecules is presented and applied to the hydrogen bonding systems. The potential energy of interaction is supposed to have electrostatic, polarization, dispersion, repulsion and effective charge-transfer contributions. Estimates of the effective charge-transfer quantity have been made based on the average charge of the proton donor and the acceptor atoms. For dimers such as water, methanol, acetic acid and formic acid, the vibrational stretching frequencies and dimerization energies are calculated and dicussed in connection with Badger-Bauer rule.

X-선 회절로 얻은 수소결합의 결합거리 보정 방법: 중성자 회절결과와 결합원자가 방법 이용 (Correction Method of the Hydrogen Bond-Distance from X-ray Diffraction: Use of Neutron Data and Bond Valence Method)

    • 한국광물학회지
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    • 제16권1호
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    • pp.65-73
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    • 2003
  • 이 연구에서는 X-선 회절법으로 측정한 수소결합의 거리를 보정하는 두 가지 방법을 제시하였다 O…O 거리가 2.5 $\AA$ 이상인 수소결합의 경우는 저온에서 측정한 중성자 회절에 의한 수소결합 데이터를 이용하여 얻은 최적화 곡선 식 d(O-H)=exp((2.173-d(O…O))/0.138)+0.958을 이용하여 수소결합 거리를 보정한다. O…O 거리가 2.5 $\AA$ 이하의 짧은 수소결합의 경우는 결합원자가 최적화 방법(valence-least-squares)을 이용하는 것이 효과적이다. X-선 회절분석으로 얻은 긴 O…O 거리를 갖는 분자간 수소결합의 경우는 수소결합의 거리보정을 해주어야 한다.

Poly(2-ethyl-2-oxazoline)/poly(acrylic acid) 계의 수소결합 특성 및 이용

  • 김진희;장우진;구윤모
    • 한국생물공학회:학술대회논문집
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    • 한국생물공학회 2000년도 추계학술발표대회 및 bio-venture fair
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    • pp.644-647
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    • 2000
  • 본 연구에서는 pH 변화에 따른 poly(2-ethyl-2-oxazoline)[PEOx]과 poly(acrylic acid)[PAA]의 수소결합 특성을 고찰하였다. PEOx와 PAA는 산성 조건(pH 4.3이하)하에서 PAA의 수소와 PEOx의 산소간에 수소결합으로 안정한 복합체를 형성하여 침전하였다. PEOx와 PAA 혼합용액을 수성이상계에 적용하기 위한 최적 반응비는 질량비 1:1.5이었고, 이 고분자 혼합용액은 수소결합을 제거한 상태에서 dextran용액과 수성이상계를 형성하였다.

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The Effect of Hydrogen Plasma on Surface Roughness and Activation in SOI Wafer Fabrication

  • Park, Woo-Beom;Kang, Ho-Cheol;Sung, Man-Young
    • Transactions on Electrical and Electronic Materials
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    • 제1권1호
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    • pp.6-11
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    • 2000
  • The hydrogen plasma treatment of silicon wafers in the reactive ion-etching mode was studied for the application to silicon-on-insulator wafers which were prepared using the wafer bonding technique. The chemical reactions of hydrogen plasma with surface were used for both surface activation and removal of surface contaminants. As a result of exposure of silicon wafers to the plasma, an active oxide layer was found on the surface. This layer was rendered hydrophilic. The surface roughness and morphology were examined as functions of the plasma exposing time and power. In addition, the surface became smoother with the shorter plasma exposing time and power. The value of initial surface energy estimated by the crack propagation method was 506 mJ/㎡, which was up to about three times higher as compared to the case of conventional direct using the wet RCA cleaning method.

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수소결합에 의한 얇은 다중벽 탄소나노튜브의 자기조립 (Hydrogen Bonding-Driven Assembling of Thin Multiwalled Carbon Nanotubes)

  • 한중탁;김선영;우종석;이건웅
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2007년도 추계학술대회 논문집
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    • pp.426-427
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    • 2007
  • Here we describe the formation of a self-assembled film of thin multiwalled carbon Nanotubes(t-MWNT) modified with hydroxy groups through hydrogen peroxide treatment. Morphologies of t-MWNT films could be controlled by the various coating method, such as filtering, drop casting, spraying method, etc. The results show that on densification of the CNT suspension during drying, multiple hydroxy group-modified MWNTs can be self-assembled through strong surface hydrogen bond interaction while MWNTs usually exist an entangled state in the film. The interaction between t-MWNT was illustrated from Raman spectrum of spray coated films.

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Modulation of chromatic reversibility of polydiacetylene Langmuir Schafer (LS) films by cadmium ion Ad/desorption

  • Lee, Gil Sun;Kim, Tae Young;Ahn, Dong June
    • Journal of Industrial and Engineering Chemistry
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    • 제67권
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    • pp.312-315
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    • 2018
  • Although the reversibility of 10,12-pentacosadiynoic amino meta-acid(PCDA-mBzA) against temperature and pH was reported, the modulation of reversibility by ion adsorption at terminal functional group has not been investigated. In this work, we developed a simple method for modulating the reversibility of PCDA-mBzA films upon a thermal stimulus by cadmium ion adsorption inducing the breakage of the outer hydrogen bonding of two hydrogen bonds, which are responsible for the reversible properties of PCDA-mBzA. External reflection-Fourier transform infrared (ER-FTIR) analyses revealed that the hydrogen bonding between the carboxylic acid groups was broken through ion adsorption and only a single hydrogen bond between the amide groups remained in the PCDA-mBzA polymer. In addition, PCDA-mBzA films could recover their original property through cadmium ion desorption. These results present that the transition between reversibility and irreversibility can be modulated artificially simply through the adsorption and desorption of metal ions.