• 분석과학
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• 제8권4호
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• pp.493-498
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• 1995

PAZO-6 is a new combined type liquid crystalline polymers (LCP) which has two types of mesogens combined non linearly. Ordering of branch mesogen azo group, in PAZO-6 is an important parameter to observe as well as the substitution effect on the backbone. The related small molecules sllch as monomers as well as the polymer itself are studied by solid state NMR techniques. Preliminary $^{13}C$ CP/MAS (cross polarization/ magic angle spinning) spectral results suggest that the azo groups in the monomers are not aligned with themselves. Azo groups in the monomers seem to be poorly ordered between well ordered p-phenylene terephthalate moeities. Similar disordering tendency of the azo group in PAZO-6 is deduced from the overall aromatic carbon peak positions which are not much different from those of the monomer.

• 한국세라믹학회지
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• 제40권5호
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• pp.434-440
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• 2003

초거대 자기 저항 물질인 페로브스카이트 L $a_{0.8}$C $a_{0.2}$Mn $O_3$의 분말을 졸-겔방법으로 제조하였다. Lanthanum(III), Calcium(II) 그리고 Manganese(III) 2,4-Pentanedionate를 Propionic acid와 methane떠 혼합용매를 사용하고 PEG (l5 wt%) 용액을 첨가 하여 안정한 졸용액을 합성하였고 FT-IR spectroscopy로 반응의 진행 정도를 관찰하였다. L $a_{0.8}$C $a_{0.2}$Mn $O_3$ 겔 분말에 대해 온도를 변화시키면서 열처리하여 FT-IR, CP/MAS $^{13}$C solid state NMR spectroscopy와 XRD등을 이용해 구조변화를 관찰하였다. 열분석은 TG/DTA로 측정하였으며, FE-SEM을 통해 입자크기와 균일도를 관찰하였고, 양이온 조성 비율을 알아보기 위해 ICP-AES를 측정하였다. 자성 특성을 규명하기 위해 VSM을 이용하여 자기 모멘트를 측정하였으며, 상자기성 에서 강자기성으로 전이되는 큐리온도( $T_{c}$)를 관찰하였다.

• 한국자기공명학회논문지
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• 제6권1호
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• pp.38-44
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• 2002

60% Pt on Vulcan XC-72 with similar Pt sizes to fuel cell grade Pt black was investigated by $\^$13/C nuclear magnetic resonance spectroscopy (NMR), cyclic voltammery (CV), transmission electron microscopy (TEM). Experiments were carried out on electrochemically cleaned samples as well as as-received. The TEM and CV results showed that the average particle sizes were changed by cleaning. However, the chemical shift （$\delta$$\_$G/） of $\^$13/C of $\^$13/CO absorbed on Pt surfaces did not show any appreciable variation with particle size change as did in Pt black. These results indicate that a combination of different analytic techniques is essential to understand the properties of the metal particle catalysts and that the presence of carbon black support strongly influences the NMR data, probably through metal-support interaction.

• Bulletin of the Korean Chemical Society
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• 제34권3호
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• pp.875-883
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• 2013

Ten new derivatives of 1,3-diazabicyclo[3.1.0]hex-3-enes linked via ether linkage to chalcones were synthesized and characterized by UV, FT-IR, $^1H$ NMR and $^{13}C$ NMR spectral techniques. The spectra of all synthesized compounds, confirmed structure-photochromic behavior relationships (SPBR) both in solution or in solid state by irradiation under UV light at 254 nm. In other efforts for first time photochromic behavior of ketoaziridines has been investigated.

• Bulletin of the Korean Chemical Society
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• 제32권1호
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• pp.77-82
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• 2011

A new high performance liquid chromatograpgy (HPLC) stationary phase that possesses an internal carbonyl functional group is synthesized by heterogeneous "graft from" method. This new stationary phase, poly (vinyl octadecanoate) grafted silica (Sil-2) is then characterized by different physico-chemical methods such as diffuse reflectance infrared fourier transform, suspension state $^1H$ NMR, solid state $^{13}C$ CP/MAS NMR, $^{29}Si$ CP/MAS NMR, elemental analysis and thermogravimetric analysis. Chromatographic properties of Sil-2 were evaluated under reversed phase condition by separating polycyclic aromatic hydrocarbons (PAHs) and comparing the chromatographic results with those on polymeric as well as monomeric octadecylated silica stationary phases.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2011년도 춘계학술대회 초록집
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• pp.146.2-146.2
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• 2011

Molecular behaviors and crystal structures of the binary hydrates of $CH_4$ and ethanol were identified by means of 13C solid-state NMR and powder XRD methods at various concentrations of ethanol. In addition, NMR peak areas were used to calculate cage occupancies for both guest species. Obtained results showed that more $CH_4$ molecules are captured into hydrate phase per unit mass of ethanol molecules because $CH_4$ molecule can occupy sII large cages more, and pure $CH_4$ hydrate can form more as well at lower ethanol concentrations. Even though tuning phenomenon was already reported for some aqueous hydrate promoters such as THF, aqueous ethanol solutions are found to play the same tuning role in the binary clathrate hydrates in this study.

• Macromolecular Research
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• 제15권7호
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• pp.633-639
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• 2007

A variety of NMR techniques were applied to the micro-chemical structural characterization of polyanilines prepared via an efficient synthetic method in a self-stabilized dispersion medium in which the polymerization was conducted in a heterogeneous organic/aqueous biphasic system without any stabilizers. Here, the monomer and growing polymer chain were shown to function simultaneously as a stabilizer, imparting compatibility for the dispersion of the organic phase, and as a form of flexible template in an aqueous reaction medium. Polymerizations predicated on this concept generated polyanilines with a low defect content: solution state $^{13}C-NMR$ and solid $^{13}CDD/CP/MAS$ spectroscopy indicated that the synthesized HCPANi and its soluble derivative, HCPANi-t-BOC, evidenced distinctly different NMR spectra with fewer side peaks, as compared to conventionally prepared PANis, and the complete structural assignments of the observed NMR peaks could be determined via the combination of both 1D and 2D techniques. Ortho-linked defects in HCPANi were estimated to be as low as 7%, as shown by a comparison of the integration of the carbonyl carbon resonance peaks.

• 공업화학
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• 제4권4호
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• pp.785-790
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• 1993

키틴의 글루코오스 단위에 메탄술폰산 존재하에서 아세트산 무수물, 프로피온산 무수물과 n-부틸산 무수물을 반응시켜 아세틸 키틴(AC), 프로피오닐 키틴(PC) 그리고 n-부티릴 키틴(BC) 등의 에스테르 형태를 갖는 개질화 키틴을 합성하였고 이들의 구조를 FT-IR과 solid state CP/MAS $^{13}C-NMR$ spectra로 확인하였다. 에스테르 형태의 키틴유도체는 대체로 키틴의 글루코오스 단위의 6번 탄소위치에 치환되었다. 유도체를 유기용매와 수용성 약산 유기용매에서 용해성을 검토하여 포름산에서 세 가지 유도체 모두 좋은 용해성을 나타냈고, 수용성 약산에서는 대부분의 유도체는 팽윤되는 것을 고찰할 수 있었다.

• 한국자기공명학회논문지
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• 제26권4호
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• pp.51-58
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• 2022

The baseline flattened NMR spectrum has been achieved by several methodologies including pulse manipulation with a series of phase cycling. The background signal inherent in the probe is also main source of baseline distortion both in solution and solid NMR. The simple direct polarization with 90° pulse flipping the magnetization from the z-axis onto the receiver coil requires the strong rf pulse enough to encompass the wide frequency range to excite the resonance of interest nuclei. Albeit the perfect polarization 90° pulse, the signal from the unwanted magnetic fields such as background signal can not be completely suppressed by suitable phase cycling. Moreover, slowly baseline wiggling signal from the low 𝛾 nuclei is not easy to eliminate with multiple pulse manipulation. So there is still need to contrive the new scheme for that purpose in an adroit manner. In this article new triple pulse excitation schemes for TIP and modified DEPTH pulse sequence are analytically examined in terms of arbitrary phase and flip angle of pulse. The suitable phase cycling for these pulse trains is necessary for the good sensitivity and resolution of the spectrum. It is observed that the ¹³C sensitivity TIP experiment is almost equal to the CP/MAS with modified DEPTH sequence, both of which are applicable to both solid and solution state NMR.

• 분석과학
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• 제17권2호
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• pp.173-179
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• 2004

Ethylene glycol의 polymerization-complex route를 통한 졸-겔 합성법으로 안정하고 균일한 barium titanate 분말 및 박막을 제조하였다. 출발 용액으로 킬레이팅 리간드인 acetylacetone을 barium과 titanium 용액에 치환시켜 합성한 복합 산화물 졸 용액을 사용했을 때 박막을 만들 수 있었다. 졸 용액의 입자 분포도는 안정한 gaussian 분포를 보였으며, $1100^{\circ}C$에서 열처리한 겔 분말의 입자 크기는 40~77 nm이었다. 열분석 및 FT-IR, $^{13}C$ CP/MAS NMR 스펙트라와 XRD 결과로부터 (Ba-Ti)-oxycarbonate 중간상을 거쳐 $BaTiO_3$ 분말이 형성됨을 알 수 있었다. Quartz에 스핀 코팅으로 제조한 박막은 치밀하고 균열 없는 미세 조직을 보였다. $1100^{\circ}C$에서 열처리한 박막 표면의 입자 크기는 220 nm였으며 치밀한 입자 성장을 관찰할 수 있었다.