• Proceedings of the Korean Vacuum Society Conference
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• 1999.07a
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• pp.56-56
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• 1999

수소화된 비정질 탄소(a-C:H0는 그 형성 조건에 따라서 여러 가지 다른 구조와 특성을 갖게 되며, 특히 DLC(diamond-like carbon)-FED(field emission display) 개발 면에서 중요하게 연구되고 있다. 본 연구에서는 a-C:H 박막을 PECVD(plasma-enhanced chemical vapor deposition) 방법으로 증착하고 주고 ESR 및 Raman 측정을 통하여 그 결과를 조사해 보았다. PECVD 증착가스는 CH4 가스를 사용하였다. 기판은 Corning 1737 glass를 사용하였고, 기판 온도는 32$0^{\circ}C$이었다. 증착 압력과 R>F. power는 각각 0.1-1 Torr 와 12-36 W 사이에서 변화되었다. ESR를 피하기 위하여, microwave power에 대한 ESR 신호 의존성을 측정하고 포화효과를 피하기 위한 Raman spectroscopy로 분석하였다. R.F.power가 증가할수록 증착속도는 0.06 nm/sec 정도까지 대체로 증가하였으나, pressure가 1 Torr 일때는 같은 R.F. power로써 증착이 일어나지 않는 경우도 발생하였다. 증착된 a-C:H 박막은 R.F.power가 증가할수록 스핀밀도의 증가가 두드러졌으며, 기타 증착가스 압력 등의 증착 조건에 따른 ESR 및 Raman 스펙트럼의 변화를 관찰하였다.

• Nuclear Engineering and Technology
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• v.32 no.3
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• pp.254-260
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• 2000

Electron spin resonance (ESR) spectroscopy was used to detect irradiated meat containing bones (chicken, pork and beef）, to investigate the effect of irradiation dose on the ESR signal intensity and to identify the stability of radicals under 9 weeks of storage. Chicken, pork and beef were irradiated with doses 0, 1, 3, 5 and 7 kGy at room temperature using a Co-60 irradiator. Bones were pieced and dried, which were placed in a quartz tube within an Electron paramagnetic resonance (EPR) spectrometer resonator cavity. The irradiated bone presented an asymmetric absorption in shape, different from that of a non-irradiated one. The signal intensity of smaller animals are lower than larger species. Variation was observed between samples of the same species depending on the calcification status of the bone. Moreover different irradiation doses produced different signal areas that make possible to estimate the absorbed dose of treated meat. The ESR signal stability after irradiation was stable in even after a 9 week storage at room temperature.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07a
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• pp.473-476
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• 2004

This study has investigated radiation degradation of low density polyethylene(LDPE). Samples were irradiated using a $Co^{60}\;\gamma-ray$ and ray up to 800 kGy at a dose rate of 5 kGy/hr in the presence of air atmosphere at room temperature. After irradiation, free radical measurement of LDPE has established by electron spin resonance(ESR). Then, each sample was stored for 2 weeks. ESR measurement showed that free radical concentration(FRC) was increased with radiation dose and changed from alkyl, allyl radical to peroxy radical with time.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.66 no.4
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• pp.213-218
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• 2017

The DC electrolytic capacitor for DC-link of power converter is widely used in various power electronic circuits and system application. Its functions include, DC Bus voltage stabilization, conduction of ripple current due to switching events, voltage smoothing, etc. Unfortunately, DC electrolytic capacitors are some of the weakest components in power electronics converters. Many papers have proposed different algorithms or diagnosis method to determinate the ESR and tan ${\delta}$ capacitance C for fault alarm system of the electrolytic capacitor. However, both ESR vary with frequency and temperature. Accurate knowledge of both parameters at the capacitors operating conditions is essential to achieve the best reference data of fault alarm. According to parameter analysis, the capacitance increases with temperature and the initial ESR decreases. Higher frequencies make the reference ESR with the initial ESRo value to decrease. Analysis results show that the proposed DC Bus electrolytic capacitor reference ESR model setting technique can be applied to advanced reference signal of capacitor diagnosis systems successfully.

• Journal of Magnetics
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• v.18 no.2
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• pp.173-177
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• 2013

Cantilever-detected high-frequency electron spin resonance (ESR) is a powerful method of sub-terahertz and terahertz ESR spectroscopy for a tiny magnetic sample at low temperature. In this technique, a small magnetization change associated with ESR transition is detected as deflection of a sample-mounted cantilever. So far, we have succeeded in ESR detection at 370 GHz using a commercial piezoresistive microcantilever. The spin sensitivity was estimated to ${\sim}10^{12}$ spins/gauss. In order to further increase the sensitivity, we adopt a fiber-optic-based detection system using a Fabry-Perot interferometer in place of piezoresistive system. Fabry-Perot cavity is formed between an optical-fiber end and microcantilever surface, and a change in the interference signal, corresponding to the cantilever deflection, is sensitively detected. This system is suitable for low-temperature and high-magnetic-field experiments because of its compact setup and less heat dissipation. In this study, performance of Fabry-Perot interferometer is evaluated, and its application to cantilever-detected ESR measurement is described.

• Pediatric Infection and Vaccine
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• v.23 no.1
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• pp.25-30
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• 2016

Purpose: We undertook this study to investigate discrepancies in C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) values, and variations following intravenous immunoglobulin (IVIG) therapy in Kawasaki disease (KD). Methods: A total of 123 KD patients were retrospectively enrolled. Patients were treated with IVIG 2 g/kg at 2 to 9 days after disease onset. We obtained white blood cell (WBC) count, percentage of neutrophils (% neutrophils), CRP, ESR, and N-terminal pro-brain natriuretic peptide (NT-proBNP) values before and 48 to 72 hours after IVIG treatment. Discrepancy was defined as $CRP{\geq}10mg/dL$ and ESR <50 mm/hr (Group 1), or CRP <10 mg/dL and $ESR{\geq}50mm/hr$ (Group 2). Results: Thirty-six of 123 subjects (29.2%) had a discrepancy: 25 (20.3%) in Group 1 and 11 (8.9%) in Group 2. In Group 1, 15 patients (60%) had fever for <5 days (early presenter) and 10 (40%) had fever for ${\geq}5days$ (late presenter). There were six early presenters (55%) and five late presenters (45%) in Group 2. Late presenters had higher ESR than early presenters ($34.3{\pm}21.0mm/hr$ vs. $26.3{\pm}19.3mm/hr$, P=0.029). After IVIG treatment, elevated WBC count, % neutrophils, CRP, and NT-proBNP levels normalized. In contrast, ESR increased from $37.4{\pm}21.9mm/hr$ to $48.0{\pm}22.7mm/hr$ (n=36, P=0.051). Conclusions: A discrepancy may be related to the duration of fever. Due to discrepancies in CRP and ESR values in acute KD, both should be measured to assess the degree of inflammatory activity before IVIG treatment. After IVIG treatment, the ESR should not be used as a marker of response to therapy in KD.

• Journal of Dairy Science and Biotechnology
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• v.28 no.2
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• pp.13-18
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• 2010

Electron Spin Resonance (ESR) spectroscopy has been used to detect the presence of radiation-induced free radicals in biological samples since the mid 1950s and to irradiate foods containing cellulose, crystalline sugar, and bone. Therefore, we analyzed the ESR spectrum of irradiated infant formula and its ingredients in this study. Samples were irradiated with 2 different radiation sources of $^{60}Co$ gamma rays and electron beams (EBs), and the absorbed doses were 0, 1, 3, 5, and 7 kGy. ESR measurements were performed under normal atmospheric conditions using a JEOL JES-FA100 spectrometer equipped with an X-band bridge. Irradiated infant formula showed anunsymmetrical spectrum ($g_1$=2.0050, $g_2$=2.0006); in contrast, non-irradiated samples showed asymmetrical spectrum. The ingredients of irradiated samples showed a multi-component ESR signal in glucose and lactose and a singlet-type spectrum in milk powder (g=2.0050). $R^2$ of the dose-response curve showed a fine linearity of over 0.95 across the entire sample. We also compared the spectra of identical samples irradiated with $^{60}Co$ gamma rays and EBs, because EBs can be used for food irradiation in foreign countries, although this is not permitted in Korea. However, we could not find any significant differences according to the types of radiation source. Thus, ESR spectroscopy can be used to detect irradiated infant formula and several types of primary ingredients in this formula.

• Economic and Environmental Geology
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• v.47 no.1
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• pp.17-27
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• 2014

We investigated space-time patterns of Quaternary fault activity of the Yangsan fault zone using ESR ages in the Samnam-myeon region, Ulsan, Korea. Some of fault gouge zones consist of well-defined bands which added to the older gouge band, indicative of reactivation. During addition of new bands, the older gouge band was inactive, which represents the type I faulting mode. ESR analyses of each band of the gouge zone allow us to construct history of fault movement. The entire fault gouge zones were reactivated by type III faulting mode giving us ESR ages of the lastest reactivation. ESR dates show temporal clustering into active and inactive periods analogous to historic and paleoseismic fault activities. ESR ages and dates of fault movements indicate migration of fault activities along the Yangsan Fault Zone. Segments of the Quaternary faults in the study area are branched in the south of Sangcheon site. The earliest record of activity in segmented faults is recorded from the western segment to the northern segment. Before 750~850 ka ago, the fault gouge zone from the western segment to the northern segment were active. At 750~850 ka ago, the fault gouge zone from the eastern segment to the northern segment were active. During 630~660 ka and 480~540 ka only the northern segment was active. After 340 ka ago, the fault gouge zone from the western segment to the northern segment were active again.

• Journal of the Korean Chemical Society
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• v.39 no.4
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• pp.237-243
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• 1995

The measurments of neutral semiquinone radicals, which were formed from the laser flash photolysis of anthraquinone (AQ) in the mixed solvents were carried out by the time resolved electron spin resonance (trESR) spectroscopy. The chemically induced dynamic electron polarization (CIDEP) spectra of the neutral semiquinone radical (AQH${\cdot}$) and semiquinone radical anion (AQ${\cdot}$-) were successively detected in the laser flash photolysis of AQ in the mixtures of 2-propanol (PrOH) and triethylamine (TEA). The neutral semiquinone radical was short-lived with the half-life of 0.8 ${\mu}sec$, whereas the semiquinone radical anion was relatively stable and then its cwESR could be observed. The rate constant of the spin-depolarization of semiquinone radical anion was $2.6{\times}10^5 sec^{-1}$ and the decay of the radical anion was the first order reaction with the rate constant of $3.0{\times}10^2\; sec^{-1}$. No CIDEP of semiquinone radical anion was observed in the mixture of PrOH and the lower concentration of TEA than 2 percent. The CIDEP spectrum of the neutral semiquinone radical was detected in the mixture of benzene and TEA with the half-life of 3.0 ${\mu}sec$. The neutral semiquinone radical could not be detected by cwESR. Neither CIDEP nor ESR absorption could be observed in PrOH, TEA or benzene only.

• Journal of the Korean Chemical Society
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• v.34 no.5
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• pp.404-412
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• 1990

The time resolved electron spin resonance spectroscopy are used to two measurement methods of chemically induced dynamic electron polarization (CIDEP) and absorption ESR. The spectra of the semiquinone radical anion were successively detected in the laser flash photolysis of anthraquinone in the mixtures of 2-propanol and triethylamine. The semiquinone radical anion was fairly stable and its cw ESR could be observed. The rate constant (T1$^{-1}$) of the spin-depolarization of polarized semiquinone radical anion was 2.6 ${\times}\;1-^5$ sec$^{-1}$ and the decay of the radical anion was the first order with the rate constant (K$_1}$) of 300.0 sec$^{-1}$. The intensity of CIDEP spectra increased with the increasing the microwave power, but the Torrey wiggles appeared following with decay curves.