• 한국세라믹학회지
• /
• 제37권5호
• /
• pp.459-465
• /
• 2000

3CaO.3Al2O3.CaSO4(C4A3)clinker was prepared by solid state reaction and then its hydration property was investigated. C4A3 clinker was fired at various temperatures in the range of 700~135$0^{\circ}C$. The hydration of it was studied by XRD, DSC, Solid-state 27Al MAS NMR and SEM. According to the results, the Ca4A3 clinker was produced by reacting calcium aluminates with CaSO4 and Al2O3 and C4A3 was formed as a main phase after calcining at 120$0^{\circ}C$. The hydration products were mainly calcium monosulfoaluminate hydrate and Al(OH)3, and they were produced after 2hrs of hydration. However the hydration rate was about 74% at 3days.

• 광물과 암석
• /
• 제34권1호
• /
• pp.31-40
• /
• 2021

명목상의 무수 광물의 수소 원자는 격자의 결함에 존재하는 것으로 알려져 있지만, 나노 스케일 입자의 경우 입자 표면에 물과 수산기의 형태로 존재할 수 있다. 본 연구에서는 비정질 규산염 나노입자의 수소 원자 환경에 대한 정량 측정 방법으로서, 1H 고상 핵자기 공명(solid-state nuclear magnetic resonance, NMR) 분광분석의 실효성을 알아보고자 하였다. 온도와 습도가 조절되는 글러브 박스 내에서 NMR 로터에 패킹된 비정질 규산염 나노입자를 25%와 70 % 상대습도에서 2일에서 10일까지 동안 보관한 후 1H NMR 스펙트럼을 측정한 결과, 약간의 차이는 있었으나 큰 변화가 관찰되지 않았다. 이는 NMR 로터에 패킹된 시료의 수소 원자 환경이 외부 대기에 의해 거의 변화하지 않았음을 의미한다. 수화 시간에 따른 비정질 규산염 나노입자의 함수량은 약 10 % 범위에서 차이를 보이며, 이는 글러브 박스의 시간적, 공간적 습도 불균일성에 의한 것으로 생각된다. 1H NMR 스펙트럼의 정량 분석 결과, 수화 상대습도가 증가함에 따라 비정질 규산염 나노입자의 수소 원자 수 역시 선형적으로 증가하였다. 이와 같은 결과는 NMR 로터의 시료 밀폐 능력이 수화 환경을 보존하며, 대기 상대습도 변화에 따른 나노입자의 함수량 변화 측정에 적합함을 의미한다. 본 연구의 결과를 통해, 1H 고상 핵자기 공명 분광분석을 이용하여 나노 스케일의 명목상의 무수 광물의 표면적, 결정도가 습도에 따른 광물의 함수량 변화에 미치는 영향에 대한 체계적인 연구를 할 수 있을 것으로 기대된다.

• 한국자기공명학회논문지
• /
• 제12권2호
• /
• pp.96-102
• /
• 2008

Direct quantification of methanol in polymer electrolyte membrane (PEM) by solid-state nuclear magnetic resonance (NMR) spectroscopy was studied and the methanol concentrations in PEM produced by crossover and diffusion were compared. The error range of the quantification was not smaller than ${\pm}15%$ and the amount of the methanol crossed over in our direct methanol fuel cells (DMFCs) was less than the methanol diffused to PEM. The methanol concentration in the PEM of the DMFC operated at different current densities were equivalent.

• 한국자기공명학회논문지
• /
• 제13권1호
• /
• pp.1-6
• /
• 2009

Syndecan-4 cytoplasmic domain was tested to confirm the interactions with the bilayer membrane using $^{31}P$ solid-state NMR measurements. Syndecan-4 was known as a coreceptor with integrins in the cell adhesion. The syndecan-4 V region is not understood of its functional roles and tested its ability of the interaction with multilamellar vesicles. The $^{31}P$ powder pattern was dramatically changed and showed isotropic peak which imply the bilayer membrane changed its topology to the micelle-like structure. Especially, phosphatidylcholine membrane was affected this effect more than phosphatidylethanolamine membrane.

• Bulletin of the Korean Chemical Society
• /
• 제29권7호
• /
• pp.1369-1373
• /
• 2008

A stable twist boat conformation of thiane S-oxide 1a in solid state and in solution was unambiguously determined by single crystal X-ray crystallography and solution NMR analyses. On the contrary, the thiane Sdioxide 2 which was obtained from the oxidation of corresponding thiane S-oxide 1a was confirmed to adopt a regular chair conformation.

• 한국자기공명학회:학술대회논문집
• /
• 한국자기공명학회 2000년도 제17회 학술발표회
• /
• pp.39-39
• /
• 2000

• Bulletin of the Korean Chemical Society
• /
• 제22권8호
• /
• pp.925-928
• /
• 2001

• 한국자기공명학회논문지
• /
• 제12권2호
• /
• pp.81-88
• /
• 2008

Solid HETCOR (Hetero-Correlation) requires homo-dipolar decoupling between proton spins during the evolution and the mixing period in 2D-NMR. There are two different ways of achieving it with pulse sequences. One is based on the multiple pulse (MP) sequence where thousands of intense radio frequency (rf) pulses are used to remove the homo-dipolar interaction between protons. The other is utilizing the so-called Lee-Goldburg (LG) off-resonance scheme where a continuous rf-irradiation is used. In this report, the advantage of one technique to the other, is analyzed. LG version is evaluated better in S/N and easier in setup procedure with the same experimental time.

• 한국자기공명학회논문지
• /
• 제11권2호
• /
• pp.110-114
• /
• 2007

[ $^{31}P$ ] powder pattern spectra were measured to investigate the aspects of the interaction between the MLV (Multilamellar vesicle) and PMAP-23, a membrane of cathelicidin family and then CSAs(chemical shift anisotropy) were calculated to indentify the extent of perturbation of phospholipid mobility by the peptides. We found that acidic phospholipid interacts strongly with PMAP-23, and the analogues which modified to increase the amphipathic property showed that larger change of CSA. The analogue which introduced positive charge showed the same effects with amphipathic property.

• 분석과학
• /
• 제10권3호
• /
• pp.196-202
• /
• 1997

새로운 바나듐(V) 착물인 $(NH_4)_2[VO_2NTA]$를 합성한 후, 용액 및 고체핵자기공명분광법 및 X-선회절법으로 그 구조를 측정하였다. 그 결과 단사결정구조(space group=$P2_1/n$)의 이 착물의 단위세포는 4 착물을 가지고 있으며, 그 파라미터는 다음과 같다 : $a=6.923(1){\AA}$, $b=8.824(2){\AA}$, $c=19.218(11){\AA}$, ${\beta}=91.60(3)^{\circ}$, 용액 및 고체에서 이 착물의 $[VO_2NTA]^{2-}$ 이온은 시스-$VO_2$ 단위를 가진 찌그러진 팔면체 구조를 가지고 있음을 알 수 있었다.