• 분석과학
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• 제12권2호
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• pp.111-115
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• 1999

간접자외선흡광검출 이온크로마토그래피를 7가지 음이온($H_2PO_4^-$, $Cl^-$, $NO_2^-$, $NO_3^-$, $I^-$, $SO_4^{2-}$, $SCN^-$)분리에 적용하였다. 컬럼은 저용량의 강염기성 음이온 교환체를 가진 상용화된 TSK-guardgel QAE-SW (ca. 0.3 meq./g; 4.6 mm i.d${\times}$150 mm)를 사용하였다. 선택적이고 신속한 이온분리방법을 연구하기 위하여 naphthalene trisulfonic acid(NTS) 및 naphthalene disulfonic acid(NDS) 용리액에 대한 분리거동을 조사하였다. 더 나아가, 0.20 mM NTS 용리액에 5% 아세토리트릴을 첨가하여 음용수에 적용한 결과, 양이온과 음이온을 동시에 분리 할 수 있었다.

• 한국응용과학기술학회지
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• 제29권2호
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• pp.278-285
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• 2012

낮은 농도와 높은 농도의 염 용액에서 Poly(styrene sulfonic acid)(PSSA) 겔의 팽윤도에 대한 이온 특성화 효과를 ${SO_3}^-$와 페닐 고리의 수소결합을 통하여 조사하였다. 낮은 농도에서 PSSA 수화 겔의 수축 정도는 ${SO_3}^-$와 물 사이의 수소 결합에 대한 음이온의 불안정화 영향 때문에 음이온에서는 $SCN^-$<$Br^-$<$Cl^-$<$F^-$의 순서를 따랐다. 재 팽윤은 계에서 특별한 상호 작용이 있을 때 높은 농도에서 관찰되었다. 반면 양이온에서 PSSA 겔의 수축은 $Li^+$<$Na^+$<$K^+$<$Ca^{+2}$ 순서를 따랐다. $Ca^{+2}$ 이온에서의 큰 수축 효과는 이가 양이온(+2)에 의한 PSSA 겔의 물리적 가교 때문에 나타난 것으로 보인다. 양이온에서의 수축은 ${SO_3}^-$와 양이온 사이의 상호작용 정도에 비례하였다. PSSA의 팽윤에 대한 이온 특성화 효과는 ${SO_3}^-$와 페닐 고리의 수화 수소결합에 대한 이온의 영향 정도, 양이온과 ${\pi}$ 전자의 상호작용, 소수성 상호작용, 그리고 분산력 등이 복합적으로 작용하여 나타난다고 볼 수 있다.

• 대한화학회지
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• 제17권3호
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• pp.169-173
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• 1973

세자리 schiff base리간드로서 salicylidene amino-o-hydroxy benzene 은 salicylaldehyde와 o-amino phenol로서 합성하였으며 이 세자리 schiff base 리간드와 Mo(VI), Mo(V), Mo(IV) 및 Mo(III) 의 과산화상태의 몰리브덴 착물들의 반응으로 새로운 착물[Mo O$_2(H_2O)\;(C_{13}H_9O_2N)]$, [MoO Cl(H$_2O)(C_13H_9O_2N)]$, $[Mo(SCN)_2(H_2O)(C_{13}H_9O2_N)]$ 및 $[Mo(H_2O)_2 (C_{13}H_9O_2N)]_2O$들을 얻었다. 이들 착물에서 Mo(VI), Mo(V) 및 Mo(IV)착물들은 리간드와 몰리브덴의 mole비가 1:1인 착물로서 몰리브덴 이온은 6배위 팔면체로서 주어지나 Mo(III) 착물은 Mo-O-Mo의 산소 bridge bond를 갖는 poly nuclear 착물로서 mole비 1:1인 착물로 주어짐을 원소분석치와 자외선흡광도 및 적외선 spectra의 고찰로서 알아보았다.

• 한국정보통신학회논문지
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• 제22권6호
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• pp.922-928
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• 2018

최근 서비스 지향 사물인터넷 네트워킹 기술에 관한 다양한 연구가 진행 중이다. 이는 사물인터넷 환경이 특정 통일 지역 내에 자신의 서비스를 제공하기 위한 다양한 서비스 디바이스들이 공존하기 때문이다. 따라서 이런 네트워크 환경은 네트워크 구성에 있어 효율적인 데이터 전달 서비스를 제공하지 못한다. 또한 이런 사물인터넷 네트워크 환경에서 효율적 서비스 제공 위해 스스로 서비스를 인지하고 서비스 별 네트워크 구성 기법이 필요하다. 따라서 본 논문에서는 다양한 서비스 디바이스로 구성된 사물인터넷 환경에서 서비스 중심 네트워크 구성이 가능한 서비스 중심 자율-구성 네트워크 (Service Oriented Self-Construction Network (SO-SCN) 기법을 제안한다. 제안하는 기법은 서비스 제공 시 필요한 네트워크 오버헤드의 최소화와 함께 네트워크 수명을 연장 할 수 있는 방법이다. 특히, 실험을 통해서 제안한 기법이 단대단 데이터 발생률과 단대단 지연 측면에서 제안하는 기법의 성능이 우수함을 증명하였다.

• Journal of Electrochemical Science and Technology
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• 제8권2호
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• pp.107-114
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• 2017

Pseudo capacitors belong to one group of super capacitors which are consisted with non carbon based electrodes. As such, conducting polymers and metal oxide materials have been employed for pseudo capacitors. Conducting polymer based pseudo capacitors have received a great attention due to their interesting features such as flexibility, low cost and ease of synthesis. Much work has been done using liquid electrolytes for those pseudo capacitors but has undergone various drawbacks. It has now been realized the use of solid polymer electrolytes as an alternative. Among them gel polymer electrolytes (GPEs) are in a key place due to their high ambient temperature conductivities as well as suitable mechanical properties. In this study, composition of a polyacrylonitrile (PAN) based GPE was optimized and it was employed as the electrolyte in a pseudo capacitor having polypyrrole (PPy) electrodes. GPE was prepared using ethylene carbonate (EC), propylene carbonate (PC), sodium thiocyanate (NaSCN) and PAN as starting materials. The maximum room temperature conductivity of the GPE was $1.92{\times}10^{-3}Scm^{-1}$ for the composition 202.5 PAN : 500 EC : 500 PC : 35 NaSCN (by weight). Performance of the pseudo capacitor was investigated using Cyclic Voltammetry technique, Electrochemical Impedance Spectroscopy (EIS) technique and Continuous Charge Discharge (GCD) test. The single electrode specific capacity (Cs) was found out to be 174.31 F/g using Cyclic Voltammetry technique at the scan rate of 10 mV/s and within the potential window -1.2 V to 1.2 V. The same value obtained using EIS was about 84 F/g. The discharge capacity ($C_d$) was 69.8 F/g. The capacity fade over 1000 cycles was rather a low value of 4%. The results proved the suitability of the pseudo capacitor for improving the performance further.

• 대한화학회지
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• 제31권6호
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• pp.527-533
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• 1987

아쿠아옥소몰리브덴(IV) 삼합체와 티오시안산이온과의 착물생성반응에 대한 속도론적 연구를 분광광도법으로 행하였다. 이 반응의 관찰된 속도상수, $k_{obsd}$는 다음과 같이 주어진다. $k_{obsd}\;=\;{k_O + k_H[H^+]^2}(SCN^-) + k_r$. 이온세기가 2.30이고 온도가 25$^{\circ}$C일때 $k_f$ 와 $k_r$의 값은 각각 $(3.78 {\pm} 0.61) {\times} 10^{-4}M^{-1}s^{-1}$ 과 $(6.93 {\pm} 2.39) {\times} 10^{-4}s^{-1}$이다. 활성화파라미터는 ${\Delta}H^*\;=\;50.71{\pm}6.91 kJmol^{-1}$이고 ${\Delta}S^*\;=\;-121.65JK^{-1}mol^{-1}$이다. 이 반응의 메카니즘에 대하여 논의된다.

• Animal cells and systems
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• 제9권3호
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• pp.153-160
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• 2005

Most living organisms exhibit the circadian rhythm in their physiology and behavior. Recent identification of several clock genes in mammals has led to the molecular understanding of how these components generate and maintain the circadian rhythm. Many reports have implicated the photic induction of either mPer1 or mPer2 in the hypothalamic region called the suprachiasmatic nucleus (SCN) to phase shift the brain clock. It is now established that peripheral tissues other than the brain also express these clock genes and that the clock machinery in these tissues work in a similar way to the SCN clock. To determine the role of the two canonical clock genes, mPer1 and mPer2, in the peripheral clock shift, stable HEK293EcR cell lines that can be induced and stably express these proteins were prepared. By regulating the expression of these proteins, it could be shown that induction of the clock genes, either mPer1 or mPer2 alone is not sufficient to cause clock phase shifting in these cells. Our real-time PCR analysis on these cells indicates that the induction of mPER proteins dampens the expression of the clock-specific transcription factor mBmal1. Altogether, our present data suggest that mPer1 and mPer2 may not function in clock shift or take part in differential roles on the peripheral circadian clock.

• Molecules and Cells
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• 제40권7호
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• pp.450-456
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• 2017

Mammalian physiology and behavior are regulated by an internal time-keeping system, referred to as circadian rhythm. The circadian timing system has a hierarchical organization composed of the master clock in the suprachiasmatic nucleus (SCN) and local clocks in extra-SCN brain regions and peripheral organs. The circadian clock molecular mechanism involves a network of transcription-translation feedback loops. In addition to the clinical association between circadian rhythm disruption and mood disorders, recent studies have suggested a molecular link between mood regulation and circadian rhythm. Specifically, genetic deletion of the circadian nuclear receptor Rev-$erb{\alpha}$ induces mania-like behavior caused by increased midbrain dopaminergic (DAergic) tone at dusk. The association between circadian rhythm and emotion-related behaviors can be applied to pathological conditions, including neurodegenerative diseases. In Parkinson's disease (PD), DAergic neurons in the substantia nigra pars compacta progressively degenerate leading to motor dysfunction. Patients with PD also exhibit non-motor symptoms, including sleep disorder and neuropsychiatric disorders. Thus, it is important to understand the mechanisms that link the molecular circadian clock and brain machinery in the regulation of emotional behaviors and related midbrain DAergic neuronal circuits in healthy and pathological states. This review summarizes the current literature regarding the association between circadian rhythm and mood regulation from a chronobiological perspective, and may provide insight into therapeutic approaches to target psychiatric symptoms in neurodegenerative diseases involving circadian rhythm dysfunction.

• 약학회지
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• 제7권2_3호
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• pp.67-71
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• 1963

Studies the reaction mechanism and optimal reaction condition of the process of preparing sodium isocyanate, by means of heating of sodium carbonate and urea. Proposing, at the sametime, the quantitative analyzing method of sodium isocyanate in the presence of impurities of $Na_{2}CO_{3}$, urea and biuret. 1. Sodium isocyanate could be prepared by means of heating reaction of sodium carbonate and urea. 2. Adding urea into the heated sodium carbonate is reasonable. 3. Quantitative analysis of sodium isocyanate in the presence of impurities, $Na_{2}CO_{3}$, urea and biuret could be done by the following method:-adding nitrobarite solution into sample solution in order to remove $CO_{3}"$ and neutralize the solution, filtering off $BaCO_{3}$, and then precipitating isocyanate as a silver salt, filtering off AgNCO, and then, titrating remaining $AgNO_{3}$ with $NH_{4}SCN$, (indicator $FeNH_{4}(SO_{4})_{2})$/TEX>

• 대한의생명과학회지
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• 제11권4호
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• pp.493-501
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• 2005

Circadian rhythms, time on a scale of about 24 hours, are present in a number of organisms including animals, plants, and bacteria. The control of the biochemical, physiological and behavioral processes is regulated by endogenous clocks in the suprachiasmatic nucleus (SCN). At the core of this timing mechanism is molecular machinery that are present both in the brain and in the peripheral tissues throughout the body, and even in a single cultured cell. In this study, we performed two-dimensional gel electrophoresis to figure out any correlation between protein expression patterns and the requirement of two canonical clock proteins, either mPER1 or mPER2, by comparing global protein expression profiles in livers from wildtype or mPer1/mPer2 double mutant mice. We could identify several differentially expressed protein candidates with respect to time and genotypes. Further analysis of these candidate proteins in detail in vivo will lead us to the better understanding of how circadian clock functions in mammals.