• 한국자기공명학회논문지
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• 제14권2호
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• pp.134-143
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• 2010

We studied the hydrogen-bonded $TlH_2PO_4$ (TDP) ferroelectrics treated with the proton-beam bombardment. The TDP material was irradiated with 1-MeV proton beam at a dose of $10^{15}/cm^2$. In order to analyze the hydrogen environment in TDP, we carried out the $^1H$ high resolution nuclear magnetic resonance (NMR) - i.e., Combined Rotation And Multiple Pulse Spectroscopy (CRAMPS) measurement. The isotropic chemical shift of hydrogen indicates its displacive property is related to the $PO_4$ lattice deformation which occurs throughout the antiferroelectric-, the ferroelastic- and the paraelastic-phase transitions. The temperature dependence of $\sigma_{iso}$ reveals the electronic charge redistribution is induced by the proton-beam irradiation and the elastic property.

• 한국융합학회논문지
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• 제5권3호
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• pp.23-27
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• 2014

최근에 스마트폰과 디바이스의 무선충전에 대한 관심이 높아지고 있으며, 많은 기업들이 무선충전을 개발하고 있다. 무선충전은 앞으로 모바일기기뿐만 아니라 노트북 청소기 등 거의 모든 전자제품으로 적용 범위가 확대될 것이다. 무선충전 전기자동차도 올해 본격적으로 선을 보일 예정이다. 이렇듯 무선충전은 연관시장이 무궁무진하다. 세계 10대 유망기술에 포함되어 있는 무선충전은 매년 100% 이상 급성장할 전망이라고 한다. 하지만 그에 따라 존재하는 기술적 한계점과 인체 유해성에 대한 보안위협을 분석해 안전한 환경에서 사용할 수 있도록 해야 하고 각종 제도적 보안도 마련해야 한다. 무선충전에 대한 표준화와 보안대책요구사항은 체계적이지 않다. 본 논문은 모바일기기에서 자기공진방식의 무선충전의 보안 위협과 보안요구사항을 정의해 분석하고자 한다.

• 센서학회지
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• 제20권4호
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• pp.226-229
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• 2011

Label-free detection of biomolecular interactions was performed using BioFET(Biologically sensitive Field-Effect Transistor) and SPR(Surface Plasmon Resonance). Qualitative information on the immobilization of an anti-IgG and antibody-antigen interaction was gained using the SPR analysis system. The BioFET was used to explore the pI value of the protein and to monitor biomolecular interactions which caused an effective charge change at the gate surface resulting in a drain current change. The results show that the BioFET can be a useful monitoring tool for biomolecular interactions and is complimentary to the SPR system.

• Bulletin of the Korean Chemical Society
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• 제27권9호
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• pp.1297-1304
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• 2006

A systematic study of the structure, energetics and spectral characteristics of substituted aminoketenes $R(NH_2)$C=C=O (R = H, $CH_3$, $NH_2$, OH, $OCH_3$, CH=$CH_2$, C$\equiv$CH, CN, CHO, NO, $NO_2$) which are highly reactive and transient intermediates in synthesis has been conducted by ab initio calculations at the MP2/6- 31G*//MP2/6-31G* level. Twenty four stable isomers of the eleven substituted aminoketenes having dihedral angles $\phi NH_2\sim120{^{\circ}}$ and $60^{\circ}$ have been identified and their optimized geometries and energies obtained. Electrostatic and steric effects on the molecular geometries have been analyzed. While the $\pi$-acceptor groups lead to planar conformations, the electron-donor groups give rise to non-planar conformations. Isodesmic substituent stabilization energies relative to alkenes have been calculated and correlation with group electronegativities established. Role of induction effect by the substituent groups and resonance effects in charge distribution in the molecules has been analyzed. An analysis of the asymmetric stretching frequencies and intensities of the C=C=O group shows that affect of non-$\pi$ acceptor substituents on the frequency is determined by the field effect (F) and resonance effect (R) parameters, the calculated intensities I (km/mol.) are correlated to group electronegativities $x$ of the substituents by the relationship I = 640.2–100.1 $x$ (r = 0.92). The $\pi$-acceptor substituents increase the intensity which may be explained in terms of their delocalizing effect on the negative charge at the $C_{\beta}$ atom.

• 대한화학회지
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• 제17권4호
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• pp.247-255
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• 1973

$Li^{+},\;Na^{+},\;K^{+}, Ca^{2+},\;Ni^{2+},\;Al^{3+}$, 과 $F^{3+}$의 陽이온을 포화시킨 Wyoning montmorillonite에 acetone, methyl-ethyl ketone. diethyl ketone을 加熱用 i.r. gas cell 內에서 各各 다른 壓力아래 吸着시켜 $4000{\sim}1200cm^{-1}$에서spectra를 얻었다.두가지 형태의 C=O결합변화가$1713cm^{-1}$과 $1690cm^{-1}$ 나타났으며 이들은 陽이온의 水酸基 및 吸着水와 그리고 表面水酸基와 水素結合을 일으키는 결과로 나타났다. OH 吸收 spectra의 强度는 陽이온의 水酸基의 resonance 理論을 뒷받침해 주었다. coordinate bond를 일으키는 경향은 計算한 C=O기의 酸素의 formal charge의 크기와 잘 맞았다.

• 전력전자학회논문지
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• 제26권6호
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• pp.437-445
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• 2021

This paper proposes an operating frequency design method that limits the voltage applied to aload-side converter during the initial operation of a loosely coupled resonant dual-active bridge (LCR-DAB) converter and an initial operating strategy that applies it. The LCR-DAB converter uses two wireless power transfer coils instead of the high-frequency transformer of the general DAB converter. The wireless power coil has a physical distance of several tens of millimeter or more between the two coils; thus, the LCR-DAB converter is a bidirectional isolated power conversion system that can easily achieve high insulation performance. However, for the initial operation of the LCR-DAB, if the power-side converter is operated at the resonance frequency while the load-side converter is not operating, then a very high voltage due to resonance is applied to the load-side converter, thereby causing damage to the converter. Therefore, a method that can stably charge the DC link voltage of the secondary-side converter during the initial operation is needed. This paper proposes a method to initially charge the secondary-side DC link by operating the primary-side converter at a frequency with limited voltage gain rather than at a steady-state operating frequency. The validity of the proposed frequency design method and initial operating sequence is verified through simulation and experimentation of the 1 KW LCR-DAB converter.

• 대한화학회지
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• 제20권5호
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• pp.380-390
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• 1976

전자 공여체로서 할로겐으로 치환되어 있는 아니솔 유도체들(아니솔, 4-클로로아니솔, 2,3-디클로로 아니솔, 2-플루오로-4-클로로아니솔, 2-브로모-4-클로로아니솔, 2-요도드-4-클로로아니솔, 2-브로모 4,6-디클로로아니솔, 2-요오드-4,6-디클로로 아니솔, 2-요오드-2,4,6-드리클로로아니솔)을 쓰고 전자를 받아들이는 화합물로서는 요오드 또는 염화 요오드를 사용하여 그 사이에 생성되는 전하이동 착물에 관하여서 사염화탄소 또는 헥산을 용매계로 하여 연구하여 보았다. 연구한 결과로서 착물의 생성량이 벤젠고리의 2-치환 할로겐 원자의 Van der Waals 반경에 따라서 영향을 받음이 확인 되었으며 더 나아가서 전자 공여 화합물 분자의 입체적 배치 환경에 의하여서도 역시 영향을 받고 있음을 알 수 있었다. 이와 같은 경향은 클로로포름과의 착물 생성에서도 핵자기 공명분석법으로 확인될 수 있었다. 분광 분석법으로 얻은 착물 생성에 관한 데이터를 제시하였으며 벤젠고리에 치환된 2-할로겐 원자의 입체구조와의 상호관계를 논의하였다.

• 한국전자통신학회논문지
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• 제17권2호
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• pp.213-218
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• 2022

본 연구에서는 드론을 무선으로 충전할 수 있는 고효율 무선 전력 전송 송, 수신 코일 개발에 대한 기술을 소개한다. 드론 스테이션은 드론의 배터리를 충전하기 위해 배터리를 분리 할 필요 없이 무선으로 배터리를 충전할 수 있는 기능을 지원한다. 드론의 배터리를 최단 시간 내에 충전하기 위해서는 무선 충전 효율이 높아야 한다. 드론 스테이션의 무선 충전 효율을 높이기 위해 고효율 송, 수신 코일 제작 방법과 성능 측정 방법을 제시하였다. 송, 수신 코일은 드론의 비행에 방해가 되지 않도록 드론의 크기와 무게를 고려하여 PCB 기판을 이용해 제작하였다. 송, 수신 코일 사이의 거리가 40mm 이상 떨어진 거리에서 88% 이상의 효율을 구현하였다.

• 한국자기공명학회논문지
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• 제19권2호
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• pp.88-94
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• 2015

Bub1 is one of the spindle checkpoint proteins and plays a role in recruitment of the related proteins to kinetochore. Here, we studied the structural characteristic of the evolutionarily conserved 160 amino acid region in the N-terminus (hBub1 CD1), using Circular Dichroism (CD) and NMR. Our CD results showed that hBub1 CD1 is a highly helical protein and its structure was affected by pH: as pH was elevated to basic pH, the helical propensity increased. This could be related to the surface charge of the hBub1 CD1. However, the structural change did not largely depend on the salt concentration, though the thermal stability a little increased. The previous NMR analysis revealed that the hBub1 CD1 adopts eight helices, which is consistent with the CD result. Our result would be helpful for evaluating the molecular mechanism of the hBub1 CD1 and protein-protein interactions.

• 한국자기공명학회논문지
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• 제16권2호
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• pp.147-161
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• 2012

Human melanocortin-4 receptor (hMC4R) among MC-Rs, expressed in the brain, is in charge of the control on energy homeostasis and food intake. The structure and function of human MC4R have been studied to understand their essential function and roles. To investigate the structure and function, it is necessary to prepare sufficient amounts of proteins. However, their expression and purification is demanding and time-consuming due to their innate insoluble and toxic properties. The heterozygous mutations of hMC4R, exchange of Asp 90 to Asn located in second transmembrane, cause severe obesity in human. To obtain purified hMC4R wt-TM2 for structural studies, it was first over-expressed and purified by fast protein liquid chromatography (FPLC) and then solution NMR studies were performed to get high-resolution spectra. In here, we established optimized purification scheme to get more purified target peptide.