• 한국자기공명학회논문지
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• 제20권4호
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• pp.109-113
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• 2016

Resonance frequencies from the $^{113}Cd$ and $^{133}Cs$ nuclear magnetic resonance (NMR) spectra for the $CsCdBr_3$ single crystal were measured at varying temperatures by the static NMR method. The temperature-dependent changes of these frequencies are related to the changing structural geometry of the ${CdBr_6}^{4-}$ units, which affects the environment of $^{133}Cs$. The spin-lattice relaxation rates ($1/T_1$) for the $^{113}Cd$ and $^{133}Cs$ nuclei were measured in order to obtain detailed information about the dynamics of $CsCdBr_3$ crystals. The dominant relaxation mechanisms for $^{113}Cd$ and $^{133}Cs$ nuclei are direct single-phonon and Raman spin-phonon processes, respectively.

• 한국자기공명학회논문지
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• 제17권2호
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• pp.92-97
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• 2013

We study the electron spin resonance line-width (ESRLW) of $Fe^{3+}$ in crystalline $LiNbO_3$ ; the ESRLW is obtained using the projection operator method (POM) developed by Argyres and Sigel. The ESRLW is calculated to be axially symmetric about the c-axis and is analyzed by the spin Hamiltonian with an isotopic g factor at a frequency of 9.5 GHz. The ESRLW increases exponentially as the temperature increases, and the ESRLW is almost constant in the high-temperature region (T>8000 K). This kind of temperature dependence of the ESRLW indicates a motional narrowing of the spectrum when $Fe^{3+}$ ions substitute the $Nb^{5+}$ ions in an off-center position. It is clear from this feature that there are two different regions in the graph of the temperature dependence of the ESRLW.

• Journal of Magnetics
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• 제13권1호
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• pp.23-29
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• 2008

The magnetic and other physical characteristics of $Mn_xSi_{1-x}Te$ have been investigated by electron magnetic resonance (EMR), X-ray diffraction (XRD) and other experiments. $Mn_xSi_{1-x}Te$ is found to have corundum structure for manganese contents up to 10% and also to be ferromagnetic for temperatures below 80 K. While ferromagnetic resonance signal coexists with the usual paramagnetic resonance signal, invariance of the g-factor inferred from the electron paramagnetic resonance signals throughout all temperature ranges clearly confirms that the manganese ions are in the electronic 3d5 state. The temperature dependence of EMR line-width is the same as other diluted magnetic semiconductors. From the EMR signals relaxation times $T_2$ and $T_1$ of $Mn_xSi_{1-x}Te$ compounds are estimated to be about $4.4{\times}10^{-10}s$ and $9.3{\times}10^{-8}s$ respectively and are found to vary slightly with temperature or composition change. Exchange narrowing of the EMR line-width becomes dominant for the sample in which the substitution ratio, x = 30%. For one sample, in which x = 0.5%, spin glass-like behavior is indicated by EMR signals for temperatures lower than 60 K. This behavior may authentic for samples within a certain range of x.

• 한국자기공명학회:학술대회논문집
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• 한국자기공명학회 2002년도 International Symposium on Magnetic Resonance
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• pp.40-41
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• 2002

• 공업화학
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• 제35권4호
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• pp.335-340
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• 2024

본 논문에서는 UIO-66에 항체 기능성을 도입한 유무기 하이브리드 소재를 합성하고 이를 표면 플라즈몬 공명(surface plasmon resonance, SPR) 분석법에 접목하여 옥시토신과 같은 작은 분자를 검출하는 감도를 향상시키고자 하였다. 옥시토신은 암, 알츠하이머, 심부전증 진단에 중요한 생물학적 표지 펩타이드 분자로 알려져 있으며, 이를 수 펨토몰(femtomole, fM) 농도 수준까지 검출하기 위해 다공성이며 표면적이 우수한 metal organic frameworks 중 하나인 UiO-66-(COOH)₂ 소재를 신호증폭용으로 활용하면서 옥시토신에 특이적인 항체 페어를 이용하는 표면 샌드위치 분석법을 개발함으로써 선택성을 향상시키고자 하였다. 이를 위해 먼저 선정한 각 옥시토신 특이적 항체가 옥시토신에 대해 강하게 결합하는지 그리고 각 항체가 옥시토신의 서로 다른 결합사이트에 결합하는지를 실시간 SPR 분석법으로 확인하였다. 선정한 항체 중 한 개(예: anti-OXT [OTI5G4])를 SPR용 금 박막 칩 표면에 고정하고, 옥시토신을 흘려준 후, UiO-66-(COOH)₂에 컨쥬게이션된 다른 항체(예: anti-OXT[4G11])를 순차적으로 흘려주어 표면에 샌드위치 복합체(anti-OXT[OTI5G4]/옥시토신/UiO-66-(COOH)₂-anti-OXT[4G11])를 형성하였을 때 옥시토신 농도에 따라 SPR 신호가 변화하는 것을 실시간으로 모니터링하였다. 그 결과, UiO-66-(COOH)₂를 사용하지 않았을 때 대비 약 백만 배 이상 감도를 증폭시켜 약 10 fM까지 검출 가능함을 보여주었다.

• 한국전기전자재료학회논문지
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• 제17권1호
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• pp.46-51
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• 2004

The cause for the variation of the initial permeability according to the Co substitution of Ni-Zn ferrite used in the LC resonance filter for the power line communication is studied. The initial permeability decreases as the quantity of Co diminishes, and the saturation magnetization increases as the quantity increases. Because the sintering density and the microstructure of ferrite show little change, the variation of the initial permeability can't be explained by the density, microstructure nor the saturation magnetization factor. The magnetocrystalline anisotropy increases, similar with the saturation magnetization, as the quantity of Co increases. The increase of magnetocrystalline anisotropy value makes the domain wall energy grow, which leads to the decrease of the initial permeability, because there's linear law between the magnetocrystalline anisotropy and the domain wall energy. The resonance frequency to Co substitution moved to high frequency band, due to the close relationship with domain wall energy, Initial permeability decreaed a little with an increase of Co contents, but resonace frequency moved to high frequency band. as a result of that, when Co was added 0.05 mol, initial permeability and resonace frequency was 75 and 25 MHz respectively.

• 한국세라믹학회지
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• 제45권3호
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• pp.179-184
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• 2008

(40-x)BaO${\cdot}xFe_2O_3{\cdot}60P_2O_5$ glasses with $5{\leq}x{\leq}35mol%$ were investigated by ESR spectroscopy. Two resonances observed near g=2.0 and g=4.3. The line at g=4.3 disappeared with the increase of the $Fe_2O_3$ content. The resonance at $g{\approx}2.0$ displayed characteristic signal consisting of superposed extremely broad and narrow components. The broader one indicates the presence of the association of two or more $Fe^{3+}$ ions, antiferromagnetically and the narrow one is related to the microclusters involving iron ions. Temperature dependence of the ESR integrated intensity revealed short-range antiferromagnetic character for $x{\geq}15mol%$.

• Ocean Systems Engineering
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• 제10권3호
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• pp.317-332
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• 2020

This study examines the behaviors and properties of discharged liquid CO₂ from a long elastic pipe moving with a vessel for the oceanic CO₂ sequestration by considering pipe dynamics and vessel motions. The coupled vessel-pipe dynamic analysis for a typical configuration is done in the frequency and time domain using the ORCAFLEX program. The system's characteristics, such as vessel RAOs and pipe-axial-velocity transfer function, are identified by applying a broadband white noise wave spectrum to the vessel-pipe dynamic system. The frequency shift of the vessel's RAO due to the encounter-frequency effect is also investigated through the system identification method. Additionally, the time histories of the tip-of-pipe velocities, along with the corresponding discharged droplet size and Weber numbers, are generated for two different sea states. The comparison between the stiff non-oscillating pipe with the flexible oscillating pipe shows the effect of the vessel and pipe dynamics to the discharged CO₂ droplet size and Weber number. The pipe's axial-mode resonance is the leading cause of the fluctuation of the discharged CO₂ properties. The significant variation of the discharged CO₂ properties observed in this study shows the importance of considering the vessel-pipe motions when designing oceanic CO₂ sequestration strategy, including suitable sequestration locations, discharge rate, towing speed, and sea states.

• 한국자기공명학회논문지
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• 제21권2호
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• pp.67-71
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• 2017

At high temperature, the roles of $NH_4$ and $H_2O$ in $(NH_4)_2Fe(SO_4)_2{\cdot}6H_2O$ and $(NH_4)_2Zn(SO_4)_2{\cdot}6H_2O$ single crystals were investigated using a pulse NMR spectrometer. Temperature was shown to have a significant influence, causing changes in the deformation of $NH_4$ and $H_2O$. From the $^1H$ NMR and $^{14}N$ NMR spectrum, the forms of environment surrounding $^{14}N$ in $NH_4$ groups is more important than the loss of $H_2O$ groups. NMR studies indicate that $NH_4{^+}$ ions in Tutton salts play an important role in the changes of the crystal structure at high temperatures.

• Journal of Magnetics
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• 제11권2호
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• pp.95-97
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• 2006

The electron spin resonance signals of $Bi_xCa_{1-x}MnO_3$ have been acquired for two samples of x=0.15 and 0.22. ESR signal of the sample of x=0.15 clearly shows signal shape change into Dysonian with g-value shift at around 165 K so that the charge ordering temperature can be identified. The general features of ESR signal of the two samples well correlate with magnetic susceptibility measurement and also confirm the validity of former investigations.