• Bulletin of the Korean Chemical Society
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• 제8권2호
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• pp.111-114
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• 1987

Temperature-dependent, solution EPR spectra of two mixed-valence copper(II)-copper(I) complexes have been simulated by using modified Bloch equations. The transition probability for the intramolecular electron transfer is determined from the simulation. The transition probabilities have been fitted to the Arrhenius equation to derive the activation energies. The transition probability also varies according to the solvent used.

• 한국포장학회지
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• 제22권1호
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• pp.7-13
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• 2016

최근 식품이나 생활용품 등의 제조기술이 발전하면서 제품을 포장하는 포장재의 재질이 단일재질에서 복합재질로 바뀌는 추세이다. 이로 인한 포장폐기물의 효율적인 처리 및 감량을 위해서 이 연구에서는 잡자재를 제외한 EPR 대상 종이팩을 중심으로 재질구조 개선에 따른 경제성 측면과 환경성 측면에서의 기대효과를 예측하였다. 특히 종이팩 포장재의 재질구조에서 재활용이 어려운 포장재인 알루미늄이 첩합된 몸체의 재질구조를 개선했을 때의 기대효과를 예측하였다. 즉, 알루미늄 첩합 멸균팩을 실리카($SiO_x$)증착 필름으로 대체하였을 경우를 가정하여 예측하였다. 경제성 기대 효과는 2015년부터 2020년까지 2등급에서 1등급 개선 후 잡자재를 제외한 EPR 대상 종이팩의 경제성 기대효과는 약 19억원으로 예상되었으며, 온실가스 중 이산화탄소($CO_2$) 감축 기대효과를 중심으로 한 환경성 기대효과는 2등급에서 1등급 개선 후 잡자재를 제외한 EPR 대상 종이팩 개선 후 예상되는 온실가스 감축효과는 약 5.5천톤 $CO_2$으로 예상된다. 이 연구에서의 기대효과 분석은 가정에 의한 한계로 인해서 기대되어지는 예상효과보다 저평가되었지만, 정부의 지침이나 추진목표에 의한 예측치와 같은 기존 방식이 아닌 데이터 계산을 통한 새로운 접근 방식이라는 점에서 의의를 갖는다.

• 한국광물학회지
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• 제21권4호
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• pp.435-442
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• 2008

천연, 합성, 그리고 처리된 보석용 다이아몬에 대한 NMR과 EPR 실험을 수행하였다. 동일한 실험조건에서 비교적 짧은 100 분의 실험시간 동안에 얻어진 $^{13}C$ NMR 스펙트럼을 통해 천연과 합성다이아몬드, 처리된 다이아몬드와 처리되지 않은 다이아몬드, 그리고 고온고압 처리된 다이아몬드와 전자빔 처리된 다이아몬드가 각각 서로 구별될 수 있는 가능성을 확인하였다. 보석용 합성 다이아몬드는 촉매제로 흔히 사용되는 전이금속의 상자기성 영향으로 $^{13}C$ NMR의 선폭이 1.6 ppm 이상으로 얻어졌고, 보석용 천연 다이아몬드는 처리방법에 무관하게 그 선폭이 0.5 ppm 이하로 얻어졌다. 고온고압 처리된 보석용 천연 다이아몬드의 선폭(0.5 ppm)은 전자빔 처리된 다이아몬드의 선폭(0.2 ppm) 보다 두 배 이상 넓은 것으로 나타났다. 처리된 보석용 천연 다이아몬드의 $^{13}C$ NMR 신호 세기는 처리되지 않은 보석용 천연 다이아몬드의 신호 세기에 비해 10배 이상 높게 얻어졌다. EPR 스펙트럼을 이용해 얻은 각 다이아몬드의 상자기성 결함(전자)의 농도와의 상관성을 검토해 본 결과, $^{13}C$ NMR 신호의 상대적 세기는 각 시료들에 함유되어 있는 상자기성 전파의 농도에 비례하여 증가하지만 전자빔 처리된 다이아몬드의 경우는 예외임이 밝혀졌다. 이를 통해 전자빔 처리된 다이아몬드의 경우 NMR 신호의 세기를 정하는 인자로 상자기성 불순물 성분 이외에 격자 성분도 고려해야 됨을 알 수 있었다.

• 한국생산제조학회지
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• 제21권4호
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• pp.532-540
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• 2012

In this study, some considerations have been suggested in developing on-site techniques to evaluate the sensitization of stainless steels. Electrochemical potentiokinetic reactivation (EPR) technique is known to be a candidate tool for field applications since it enables quantitative assessment in reasonable test time, compared to oxalic etching (ditch) technique. The on-site application of the test method imposes additional restrictions on the selection of the test method (for example, minimum surface preparation requirement, insensitivity to testing temperature, etc.). The EPR and etching techniques have been compared in order to sensitization of stainless steel structures. It has been widely reported that the maximum sensitivity in the welded structure of stainless steel is shown at heat-affected zone (HAZ) than weldments with cast structure. In this work, sectioned weldments and external surfaces were investigated to reveal the degree of sensitization by the etching and the results were compared with those of EPR test. The EPR test showed little sensitivity to surface roughness and test temperature.

• Parasites, Hosts and Diseases
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• 제49권4호
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• pp.441-443
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• 2011

This survey was performed to investigate and compare egg positive rates (EPRs) of Enterobius vermicularis among preschool children in 3 Korean localities (Chuncheon-si, Inje-gun, and Paju-si) in 2008. A total of 7,048 preschool children were examined. Overall, the total EPR was 4.0%; the EPR was the highest in Chuncheon-si (5.6%), followed by Inje-gun (4.5%) and Paju-si (3.4%). The EPR of boys (4.9%) was higher than that of girls (3.1%). The EPR significantly increased with age, with the highest observed in 5~7-year-olds. These findings demonstrate that E. vermicularis infection is widely prevalent among preschool children in Chuncheon-si, Inje-gun, and Paju-si, Republic of Korea.

• 대한안전경영과학회지
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• 제13권4호
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• pp.193-199
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• 2011

In the past annual recycling obligation rate calculation of Extended Producer Responsibility (EPR) system, it was difficult to operate the system efficiently, because responsible producers passively participated in the scheme only bent on achieving annual obligation without long-term plan. Thus, a new scheme of long-term recycling obligation rate began to be established every five year from 2008 in order to give the basis for the notice of annual specific operation standard and recycling obligation, thereby helping responsible producers to make a preparation with a plan and giving expectation of active operation of the scheme. However, in the operation of long-term recycling target program, while the development of prediction models and the evaluation for existing items has been conducted in various ways, applications for a new target items and the evaluation are quite insufficient. Therefore, in this study, problems in implementing long-term recycling goal of new target items will be examined, and more objective and rational long-term recycling rate calculation and the operation standard will be proposed. Thus, the long-term recycling target will play a role as a pacemaker to steadily improve the recycling performance of target items, and responsible producers will be expected to increase the achievement with the realistic capacity.

• 대한안전경영과학회지
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• 제13권1호
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• pp.121-126
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• 2011

The provisions regarding the standard cost for recycling stated under the Extended Producer Responsibility (EPR) since 2002, include different and complicated obligatory steps to be taken on a variety of subject items regarding the collection, the transportation and the treatment, making the corporations face in their calculating and executing the standard cost. This study presents more objective calculation scope and standard for the purpose of efficient operation of the standard cost for recycling, in consideration of the general industry perception toward cost issue as well as domestic/overseas case studies regarding the standard cost for recycling. Besides, the study presents the checking items and the calculation contents per step to calculate the standard cost for recycling. Therefore, it is expected not only to be used as the objective standard to calculate the standard cost for recycling, but also to contribute to increasing the work efficiency in the following ongoing re-calculation process and to maintaining the consistent operation of the institution.

• Bulletin of the Korean Chemical Society
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• 제15권9호
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• pp.752-758
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• 1994

Several one-electron reduction products of ${\gamma}$(1,2)-[$H_nSiV_2W_{10}O_{40}]^{(6-n)-}$ were separated by precipitating or coprecipitating with diamagnetic host compounds at different pH. Mono-and diprotonated species, 1 and 2, in powder samples exhibit aPR spectra characteristic of a mononuclear oxovanadium species, indicating that the unpaired electron is trapped at one vanadium atom. The EPR spectrum of the unprotonated species 0 shows 15 parallel lines, indicating that the unpaired electron interacts equally with two vanadium atoms. While different species were precipitated depending upon the pH of the solution and the charge of the host anion, only one species 1' was formed in the frozen solutions at pH 3.2-4.7. The EPR spectrum of 1' indicates that the unpaired electron is trapped at one vanadium atom and 1/16 of the spin density is delocalized onto the second vanadium atom. The species 1' is probably another form of the monoprotonated species. The EPR spectra show that some of 2 transform into 1 and some of 0 transform into 1' in the solid state at low temperatures. It is suggested that proton transfer between the heteropolyanion and water molecues in the solid state is involved in these transformations.

• Bulletin of the Korean Chemical Society
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• 제15권6호
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• pp.465-468
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• 1994

The charge transfer compounds $(TTF)_4FeCl_3{\cdot}CH_3OH,\;(TTF)_4SbCl_4\;and\;(TTF)_5(SbBr_4)_2{\cdot}CH_3COCH_3$ were prepared from reactions of the TTF (tetrathiafulvalene) and metal halides. The compounds were characterized by spectroscopic (UV,IR, EPR and XPS) methods, magnetic susceptibility and electrical conductivity measurements. The d.c electrical conductivities of the pressed pellets are in the order of $10^{-1}-10^{-3} Scm^{-1}$, which lies in the range of semiconductor region at room temperature. It means that the partially ionized TTF has stacked in low-dimensional chain in each compound. Spectroscopic properties also indicate that TTF molecules are partially ionized and charge transfer has occurred from (TTF)n to Fe(III) center in $(TTF)_4FeCl_3{\cdot}CH_3OH$ whereas to the $-SbX_4^-$ entity in $(TTF)_4SbCl_4\;and\;(TTF)_5(SbBr_4)_2{\cdot}CH_3COCH_3$. The EPR g values are consistent with TTF radical formation and EPR linewidths suggest the delocalization of unpaired electrons along TTF stacks. A signal arised from metal (Fe and Sb) ions were not detected in EPR spectra, indicating that metal ion is in the diamagnetic state in each compound. The diamagnetic state was also examined by the magnetic susceptibility measurement. The magnetic properties reveal the significant interaction between the $TTF^+$ radical cations in the stacks. The oxidation state of metal ions was also investigated by XPS spectra.

• Nuclear Engineering and Technology
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• 제55권1호
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• pp.270-277
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• 2023

Exposure to ionizing radiation induces free radicals in human nails. These free radicals generate a radiation-induced signal (RIS) in electron paramagnetic resonance (EPR) spectroscopy. Compared with the RIS of tooth enamel samples, that in human nails is more affected by moisture and heat, but has the advantages of being sensitive to radiation and easy to collect. The fingernail as a biological sample is applicable in retrospective dosimetry in cases of localized hand exposure accidents. In this study, the dosimetric characteristics of fingernails were analyzed in fingernail clippings collected from Korean donors. The dose response, fading of radiation-induced and mechanically induced signals, treatment method for evaluation of background signal, minimum detectable dose, and minimum detectable mass were investigated to propose a fingernail-EPR dosimetry protocol. In addition, to validate the practicality of the protocol, blind and field experiments were performed in the laboratory and a non-destructive testing facility. The relative biases in the dose assessment result of the blind and field experiments were 8.43% and 21.68% on average between the reference and reconstructed doses. The results of this study suggest that fingernail-EPR dosimetry can be a useful method for the application of retrospective dosimetry in cases of radiological accidents.