• Nuclear Engineering and Technology
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• v.55 no.10
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• pp.3831-3843
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• 2023

The adsorption behaviour of Se(-II) onto granite and MX-80 bentonite in Ca-Na-Cl solutions has been studied utilizing adsorption experiments and surface complexation modelling. Adsorption kinetic experiments allude to steady-state adsorption periods after 7 days for granite and 14 days for MX-80 bentonite. Batch adsorption experiments were carried out to determine the influence that the physicochemical solution properties would have on Se(-II) adsorption behaviour. Adsorption of Se(-II) onto granite and MX-80 bentonite follows the trend of anionic adsorption, with a decrease in R_d values as the solution pH increased. There is also an ionic strength influence on the adsorption of Se(-II) onto granite with a decrease in the R_d value as the ionic strength increased. This effect is not found when observing Se(-II) adsorption onto MX-80 bentonite. Final experiments with a representative groundwater, determined that the adsorption of Se(-II) onto granite and MX-80 bentonite returned R_d values of (1.80 ± 0.10) m³·kg^-1 and (0.47 ± 0.38) m³·kg^-1, respectively. In support of the experiments, a surface complexation modelling approach has been employed to simulate the adsorption of Se(-II) onto granite and MX-80 bentonite, where it was determined that two different surface complexes, ≡S_Se^- and ≡SOH₂⁺_H₂ were capable of simulating Se(-II) adsorption behaviour.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.77.1-77.1
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• 2010

반도체 나노 결정은 크기와 모양에 따라 다른 광학적 전기적 성질을 보이는 독특한 특성 때문에 태양전지, 발광 다이오드, 레이저, 바이오메디컬 레이블링 등에 응용될 수 있는 저가격의 차세대 광전기 재료의 개발을 위한 구조체로 각광받고 있다. 최근에는 하나의 나노 결정에 type-II band offset을 가지는 두 개의 물질을 결합한 이종접합 나노 결정체의 연구가 활발하게 진행되고 있는데, 이는 나노 결정 내에서 빛에 의해 생성된 전하들을 공간적으로 분리해 낼 수 있는 장점을 가지고 있기 때문에 태양전지나 광촉매로의 응용에 매우 유용하다. 우리는 나노 결정과 고분자 하이브리드 태양전지의 제작에 있어서 성분과 type-II 이종접합 반도체 나노 결정의 영향을 조사하기 위하여 CdSe, CdTe, type-II CdTe/CdSe tetrapod을 합성하였다. CdSe tetrapod과 P3HT의 블렌딩에 의해 만들어진 태양전지는 AM 1.5, 100mW/$cm^2$ 조건에서 1.03%의 가장 높은 변환 효율, 그리고 415nm에서 43%의 IPCE를 나타내었다. 그리고 CdTe/CdSe type-II tetrapod 이종접합과 P3HT 블렌딩으로 만들어진 태양전지는 CdTe를 이용하여 만든 태양전지에 비해 4.4배의 변환효율과 3.9배의 단락전류를 나타내었다.

• Journal of the East Asian Society of Dietary Life
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• v.25 no.4
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• pp.631-642
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• 2015

The purpose of the study was to examine health status and mini nutritional assessment (MNA) according to self-esteem status of elderly in care hospital. The survey was carried out from $13^{th}$ to $31^{st}$ of September, 2014 in five care hospitals. Analysis was performed for 226 subjects. Evaluation criteria included demographics, clinical status, MNA, health-related quality of life (EQ-5D) and self-esteem. The SE I, SE II and SE III groups were divided by self-esteem scores. Data were analyzed one-way ANOVA, Duncan' multiple range test and Pearson's correlation using SPSS 15.0. Education level, religion, dental condition and medical endurance type were significantly different in all groups. Many elderly people were normal BMI ($20.94{\sim}21.67kg/m^2$). Self-esteem significantly increased in order of SE I, SE II and SE III. Mobility, usual activity and anxiety or depression were significantly different in all groups, and EQ-5D of SE II and SE III groups were significantly higher than that of SE I group. Comparison of MNA screening score in elderly patients was as follows : Score for food intake, psychological stress or acute disease, neuropsychological problems, pressure scores or skin ulcer, protein intake, mode of feeding, nutritional status and health status in SE I group were significantly lower than those of SE II and SE III groups. Mobility and drug intake of SE I group were significantly lower than those of SE III groups. Fruit and vegetable intake SE I group were significantly higher than those of SE II and SE III groups. MIS (Malnutrition Indicator Score) was significantly different among the SE I, SE II and SE III groups. We conclude that self-esteem score is positively correlated with protein intake, nutrition status, health status and MIS in elderly care hospital. To improve nutritional status of elderly in care hospitals, systematic nutrition management and self-esteem education program should be implemented.

• Journal of the Korean Ceramic Society
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• v.55 no.5
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• pp.510-514
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• 2018

Colloidal semiconductor quantum dots (QDs), because of the novel optical and electrical properties that stem from their three-dimensional confinement, have attracted great interest for their potential applications in such fields as bio-imaging, display, and opto-electronics. However, many semiconductors that can be exploited for QD applications contain toxic elements. Herein, we synthesized non-toxic ZnTe/ZnSe (core/shell) type-II QDs by pyrolysis method. Because of the unique type-II character of these QDs, their emission can range over an extended wavelength regime, showing photoluminescence (PL) from 450 nm to 580 nm. By optimizing the ZnSe shell growth condition, resulting ZnTe/ZnSe type-II QDs shows PL quantum yield up to ~ 25% with 35 nm PL bandwidth. Using a simple two step cation exchange reaction, we also fabricated ZnTe/ZnSe type-II QDs with absorption extended over the whole visible region. The visible-light sensitized heavy metal free ZnTe/ZnSe type-II QDs can be relevant for opto-electronic applications such as displays, light emitting diodes, and bio-imaging probes.

• Journal of the korean academy of Pediatric Dentistry
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• v.35 no.3
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• pp.389-398
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• 2008

The purpose of this study was to evaluate the effects of collagenase and esterase on dentin bond strength and nanoleakage. Resin composites were bonded to occlusal dentin of premolars with Single Bond 2(SB) and Clearfil SE Bond(SE). After the microtensile specimens were prepared and stored in PBS for 24 hours(I) or, PBS(II), collagenase(III), esterase(IV) solution for 4 weeks, the specimens were stained with silver nitrate solution. Microtensile bond strength(${\mu}TBS$) and silver penetration area were measured and, the results were as follows: 1. For group II, III, and IV, the bond strengths of SB were lower than those of SB(p<0.05). The bond strengths of SB II, III, and IV were lower than that of SB I(p<0.05). There was no difference among the bond strengths of SE $I{\sim}IV$ groups(p>0.05). 2. Silver penetration areas of SB were higher than those of SE for all storage groups(p<0.05). In SB and SE groups, there was no significant difference of silver penetration area among $I{\sim}IV$ groups(p>0.05). 3. SE I, II, and III showed inverse relationship between the bond strengths and the silver penetration areas(p<0.05).

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.27 no.3
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• pp.178-183
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• 2014

Recently, various type of nanomaterials such as nanorod, nanowire, nanotube and their core/shell nanostructures have attracted much attention in photocatalyst due to their unique properties. Among them, Type-II core/shell heterostructures have extensively studied because it has exhibited improved electrical and optical properties against their single-component nanostructure. Such structures are expected to offer high absorption efficiency and fast charge transport due to their stepwised energetic combination and large internal surface area. Thus, it has been considered as potential candidates for high efficient photocatalytic activity. In this work, we introduce a novel chemical conversion process to synthesize Type-II ZnO/ZnSe core/shell heterostructures. A plausible conversion mechanism to ZnO/ZnSe core/shell heterostructres was proposed based on SEM, XRD, TEM and XPS analysis. The ZnO/ZnSe heterostructures exhibited excellent photocatalytic activity toward the decomposition of RhB dye compared to the ZnO nanorod arrays due to enhanced light absorption and the type-II cascade band structure.

• Korean Journal of Environmental Agriculture
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• v.38 no.1
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• pp.47-53
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• 2019

BACKGROUND: This experiment was conducted to examine the effects of organic Se concentration and the number of foliar applications on growth characteristics and Se content in rice. METHODS AND RESULTS: A series of multiple foliar applications were performed at (1) 3 times (maximum tillering stage + booting stage + heading stage), (2) 4 times I (effective tillering stage + maximum tillering stage + booting stage + heading stage), (3) 4 times II (maximum tillering stage + booting stage + heading stage + grain filling stage) according to the development stage. Each set of the foliar application plots was treated with 0, 10, 20, 40, 60, 100 ppm of Se and with mixed pesticide ($P^*$ + Se 40 ppm) in which the treatment time was the same as that of the treatment 4 times II. The total cultivation period of rice was 184 days. Se contents in rice (brown rice, white rice) were analyzed by ICP. CONCLUSION: The number of grains per head tended to decrease with increasing concentrations of organic Se in all treatments. However, number of panicles per hill did not show statically significant differences between the 3 times and 4 times I treatments. The grain yield decreased with the 3 times and 4 times II, but there was no significant difference in 4 times I. Se content in brown rice was the highest at 100 ppm Se (5268.64) treatment and lowest at 10 ppm Se ($1269.19{\mu}g{\cdot}kg^{-1}$) treatment. Se content in the polished rice was the highest at 100 ppm Se (5047.33) treatment and lowest at 10 ppm Se ($885.05{\mu}g{\cdot}kg^{-1}$) treatment. The higher selenium was treated, the higher Se content was found in the rice (brown rice, polished rice).

• Nuclear Engineering and Technology
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• v.54 no.5
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• pp.1616-1622
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• 2022

Selenium has been identified as an element of interest for the safety assessment of a deep geological repository (DGR) for used nuclear fuel. In Canada, groundwaters at DGR depths in sedimentary rocks have been observed to have a high ionic strength. This paper examines the sorption behavior of Se(-II) onto illite, MX-80 bentonite, Queenston shale, and argillaceous limestone in Na-Ca-Cl solutions of varying ionic strength (0.1-6 mol/kgw (m)) and across a pH range of 4-9. Little ionic strength dependence for Se(-II) sorption onto all solids was observed except that sorption at high ionic strength (6 m) was generally slightly lower than sorption at low ionic strength (0.1 m). Illite and MX-80 exhibited the expected results for anion sorption, while shale and limestone exhibited more constant sorption across the pH range tested. A non-electrostatic surface complexation model successfully predicted sorption of Se(-II) onto illite and MX-80 using the formation of an inner-sphere surface complex and an outer-sphere surface complex. Optimized values for the formation reactions of these surface species were proposed.

• Journal of the Korean Vacuum Society
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• v.1 no.2
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• pp.244-253
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• 1992

BiSI, BiSI : Co, BiSeI 및 BiSeI : Co 단결정을 고순도의 성분원소와 8.6mole% 과잉의 Iodine를 투명석영관내에 넣고 진공봉입하여 합성한 ingot를 사용하여 수직 Bridgman 방법으로 성장시켰다. 성장된 단결정은 orthorhombic 구조였고, energy band 구 조는 간접전이형으로 293K에서 광학적 energy gap은 각각 1.590eV, 1.412eV, 1.282eV 및 1.249eV로 주어지며, energy gap의 온도의존성은 Varshni 방정식으로 잘 표현된다. Cobalt 를 첨가할 때 나타나는 불순물 광흡수 peak는 Td symmetry점에 위치한 Co2+, Co3+ ion의 energy 준위들 사이의 전자전이에 의해서 나타난다.

• Journal of the Korean Vacuum Society
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• v.6 no.1
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• pp.50-60
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• 1997

Undoped, cobalt-doped and erbium-doped $ZnAl_2S_4, ;ZnAl_2Se_4, ;CdAl_2S_4, ;and;CdAl_2Se_4$ single crystals were grown by the chemical transport reaction method. The crystal structures, the lattice constants, the optical energy gaps, and the photoluminescence properties of these single crystals were investigated. Also, the optical transition mechanisms by the impurities of cobalt and erbium were identified from these results.