• 분석과학
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• 제11권6호
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• pp.421-428
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• 1998

사용후핵연료의 화학특성을 규명하기 위하여 시료 중에 함유되어 있는 핵분열생성물 중 Zr을 분리, 정제하는 연구를 수행하였다. 우라늄과 핵분열생성물 대신 비방사성 금속이온들로 구성된 사용후핵연료 모의 용해용액을 시료로 사용하였다. 12 M HCl 용액으로 전처리한 Dowex $1{\times}8$ 음이온교환수지관에서 Ce, Nd, Cs, Rb, Ba, Sr, Ru, Rh, Pd, Ag 및 Cd을 용리시킨 후 5 M HCl 용액으로 Zr을 95% 이상 분리, 회수할 수 있었다. 용출액에 함유되어 있는 Zr 동위원소의 동중원소인 Mo을 제거하기 위하여 5 M HCl 용액으로 전처리한 Dowex $1{\times}8$ 음이온교환수지관에서 정제하였으며, 실제 PWR 사용후핵연료에 함유되어 있는 Zr 분리, 정제에 적용하여 질량분석한 결과 Mo 및 Sr에 의한 동중원소 영향이 나타나지 않았다.

• 한국한의학연구원논문집
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• 제1권1호
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• pp.209-244
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• 1995

The time therapy in oriental medicine is to reserch physiological activity and pathological variation with time, or time with disease. In that, this therapy is to research the development of disease, progress, diagnosis, treatment, and the meaning of preventive medicine. The theory of time therapy has been developed form heaven-human corresponding principle, and fourtimes of seasons is related with human life. After that, this theory affects in yin-yang five circle principle and organ-meridian match system. The independent development was formed later, but the origin has progressed for a logn times. in relation with time therapy, traditional acupuncture therory suggested five semen. In twenty century, the doctor rheinhold voll suggested energy exchange theory, this theory is based on time therapy, but has partial differance also too. His oppinion is this´ the energy present in the body has a circulation following the acupuncture teaching, i.e., the organs and their meridians are flooded in a certain sequence by this flowing energy. This maximum times of the organs are of physiologic and pathologic significance to man. In next time, we will discuss the indivisual theory in detail, and wil have comparison, and considering too.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2000년도 가을 학술발표회 논문집
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• pp.435-442
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• 2000

Batch test and column test were performed to develop the design factors for permeable reactive barriers(PRBs) against ammonium and heavy metals, Clinoptilolite, a kind of natural zeolites having excellent cation exchange capacity(CEC), was choosen for the reacting materials through the ion-exchange mechanism. In the batch test, the reactivity of clinoptilolite for ammonium, lead, and copper was examined varying the initial concentration of contaminants(ammonium: 20, 40, 80 ppm, heavy metals: 10, 20, 40 ppm) and the particle size of clinoptilolites(0-0.15, 0.42-0.85, 1-1.25 mm). The reactivity is increasing as the initial concentration decrease and particle size decrease. In the column test, the permeability and the reactivity of the specimens were examined using flexible-wall permeameter. Specimens were made of clinoptilolite and Jumunjin-sand with 20 : 80 weight ratio varying particle size of clinoptilolite. The maximum permeability(1${\times}$10$\^$-4/-5${\times}$10$\^$-5/cm/s) was achieved in the specimen made of 0.42-0.85 mm clinoptilolite and sand.

• 설비공학논문집
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• 제27권3호
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• pp.169-173
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• 2015

Recently, ground source heat pump (GSHP) systems have attracted much attention, according to the enhanced social demand of renewable energy. GSHP systems can achieve higher coefficient of performance than the conventional air-source heat pump systems by utilizing stable underground temperature. However, the initial cost of GSHP system is higher than that of the conventional systems, especially, in the small-size buildings. Therefore, it is necessary to develop small-size ground heat exchanger with low cost and quick installation. In this study, a unit-type ground heat exchanger was developed and heat exchange rate was calculated by the numerical simulation. As a result, 27.45 W/m of heat exchange rate was acquired in the condition of $0.5m{\times}0.2m{\times}2m$ unit.

• 안보군사학연구
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• 통권2호
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• pp.261-283
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• 2004

To build up the military strength based on information oriented armed forces, the Korean ministry of national defense (MND) promotes the defense CALS (Continuous Acquisition and Life cycle Support) initiative for the reductions of acquisition times, improvements of system qualities, and reductions of costs. These defense CALS activities are the major component of the underlying mid and long term defense digitization program and the ultimate goal of program is to bring a quick victory by providing real-time battlefield intelligence and the economical operations of the military. The concept of defense CALS is to automate the acquisition and disposition of defense systems throughout their life cycle. For implementing defense CALS, the technology for exchange and sharing CALS standard data that is created once and used many times should be considered. In order to develop an efficient CALS information exchange and sharing system, it is required to integrate distributed and heterogeneous data sources and provide systematic search tools for those data. In this study, we developed a content based search engine technology which is essential for the construction of integrated data environments. The developed technology provides the environment of sharing the CALS standard data such as SGML(Standard Generalized Markup Language) and STEP(Standard for The Exchange of Product model data). Utilizing this technology, users can find and access distributed and heterogeneous data sources without knowing its actual location.

• Nuclear Engineering and Technology
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• 제15권2호
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• pp.142-148
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• 1983

핵급물질에 함유된 미량 희토류윈소인 Sm, Eu, Gd, Dy를 개별 분리하기 위해 Dowex50W$\times$8 양이온교환수지와 $\alpha$-hydroxyisobutyric acid ($\alpha$-HIBA) 사이에서 분배계수를 측정하였다. 양이온교환수지를 이용하여 우라늄매질로부터 미량희토류원소를 군분리한 후 0.40M$\alpha$-HIBA용리액의 pH를 3.40에서 3.60까지 변화시키면서 개별분리하였다. Sm, Eu, Dy은 형광분석법으로 Gd은 비색법으로 정량하였으며 실험결과를 토대로하여 magnesium diuranate(yellow cake) 중의 Sm, Eu, Gd, Dy를 각각 정량하였다

• 공업화학
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• 제22권3호
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• pp.255-260
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• 2011

$K^{+}-{\beta}^{{\prime}{\prime}}$-alumina pellet를 이온교환 매체인 ammonium nitrate 수용액과 용융염으로 각각 이온교환하여, 고온형 PEMFC 전해질로 기대되는 무기소재인 $NH_4{^+}-{\beta}^{{\prime}{\prime}}$-alumina를 제조하였다. 고압반응기의 실험조건으로 온도는 130, 150, 170, $200^{\circ}C$ 에서, 시간은 2 h 간격으로 2 h에서 8 h까지 수열반응을 실시하였으며 이 때의 수용액의 농도는 5 M과 10 M을 사용하였다. 또한 $200^{\circ}C$의 가열기 위에서 ammonium nitrate를 완전히 녹여 용융염 상태의 ammonium nitrate를 이용하여 2 h 간격으로 2 h에서 8 h까지 이온교환을 실시하였다. 이온교환반응의 반복횟수에 따른 영향을 알아보기 위하여 재이온교환반응을 3차까지 반복해서 실험하였다. 이후 이온교환 된 $NH_4{^+}-{\beta}^{{\prime}{\prime}}$-alumina 구조체의 상 안정성, 이온교환율을 각각 X선 회절기(Rigaku Rint 2000, Japan)와 ICP-AES (Spectro, Modular EOP)를 사용하여 분석하였다.

• Journal of Magnetics
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• 제21권2호
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• pp.159-163
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• 2016

Antiferromagnet (AFM)/ferromagnet (FM) bilayer structures are widely used in the magnetic devices of sensor and memory applications, as AFM materials can induce unidirectional anisotropy of the FM material via exchange coupling. The strength of the exchange coupling is known to be sensitive to quality of the interface of the AFM/FM bilayers. In this study, we utilize proton irradiation to modify the interface structures and investigate its effect on the magnetic properties of AFM/FM structures, including the exchange bias and magnetic thermoelectric effect. The magnetic properties of IrMn/CoFeB structures with various IrMn thicknesses are characterized after they are exposed to a proton beam of 3 MeV and $1{\sim}5{\times}10^{14}ions/cm^2$. We observe that the magnetic moment is gradually reduced as the amount of the dose is increased. On the other hand, the exchange bias field and thermoelectric voltage are not significantly affected by proton irradiation. This indicates that proton irradiation has more of an influence on the bulk property of the FM CoFeB layer and less of an effect on the IrMn/CoFeB interface.

• 한국수소및신에너지학회논문집
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• 제33권1호
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• pp.28-37
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• 2022

In this study, we synthesized a poly(pheneylene oxide) (PPO)-based organic/inorganic composite membrane having silicotungstic acid (STA) for the development of an anion exchange membrane with excellent ionic conductivity and physicochemical stability. The organic/inorganic composite membranes were prepared by introducing different STA contents (0 wt%, 10 wt%, 30 wt%, and 50 wt%) into the quaternizaed(Q)-PPO matrix. The prepared anion exchange membranes were subjected to structural analysis by proton neclear magnetic resonance and Fourier transform infrared, and thermal behavior of membranes was confirmed by thermogravimetric analysis. Among the prepared composite membranes, the ion conductivity of Q-PPO/STA-50 (40.5 mS cm^-1) showed 1.46 times compared to that of the pristine membrane (27.6 mS cm^-1). Therefore, these results demonstrated that organic/inorganic composite membranes are promising candidates for application of anion exchange membranes.

• 대한수학회보
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• 제50권5호
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• pp.1711-1723
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• 2013

P. V$\acute{a}$mos called a ring R 2-good if every element is the sum of two units. The ring of all $n{\times}n$ matrices over an elementary divisor ring is 2-good. A (right) self-injective von Neumann regular ring is 2-good provided it has no 2-torsion. Some of the earlier results known to us about 2-good rings (although nobody so called at those times) were due to Ehrlich, Henriksen, Fisher, Snider, Rapharl and Badawi. We continue in this paper the study of 2-good rings by several authors. We give some examples of 2-good rings and their related properties. In particular, it is shown that if R is an exchange ring with Artinian primitive factors and 2 is a unit in R, then R is 2-good. We also investigate various kinds of extensions of 2-good rings, including the polynomial extension, Nagata extension and Dorroh extension.