• 대한화학회지
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• 제63권4호
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• pp.260-265
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• 2019

Alcohol dehydrogenase (ADH) (EC 1.1.1.1) was selected as the enzyme which will be immobilized on ultrafiltration membrane by fouling with different transmembrane pressure of 1, 2 and 3 bars. ADH will catalyze formaldehyde (CHOH) to methanol ($CH_3OH$) and simultaneously oxidized nicotinamide adenine dinucleotide (NADH) to $NAD^+$. The concentration of enzyme and pH are fixed at 0.1 mg/ml and pH 7.0 respectively. The objective of the study focuses on the effect of different transmembrane pressure (TMP) on enzyme immobilization in term of permeate flux, observed rejection, enzyme loading and fouling mechanism. The results showed that at 1 bar holds the lowest enzyme loading which is 1.085 mg while 2 bar holds the highest enzyme loading which is 1.357 mg out of 3.0 mg as the initial enzyme feed. The permeate flux for each TMP decreased with increasing cumulative permeate volume. The observed rejection is linearly correlated with the TMP where increase in TMP will cause a higher observed rejection. Hermia model predicted that at irreversible fouling with standard blocking dominates at TMP of 3 bar, while cake layer and intermediate blocking dominates at 1 and 2 bar respectively.

• 한국분말재료학회지
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• 제26권3호
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• pp.220-224
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• 2019

The aluminum (Al)/copper oxide (CuO) complex is known as the most promising material for thermite reactions, releasing a high heat and pressure through ignition or thermal heating. To improve the reaction rate and wettability for handling safety, nanosized primary particles are applied on Al/CuO composite for energetic materials in explosives or propellants. Herein, graphene oxide (GO) is adopted for the Al/CuO composites as the functional supporting materials, preventing a phase-separation between solvent and composites, leading to a significantly enhanced reactivity. The characterizations of Al/CuO decorated on GO(Al/CuO/GO) are performed through scanning electron microscopy, transmission electron microscopy, and energy dispersive X-ray spectroscopy mapping analysis. Moreover, the functional bridging between Al/CuO and GO is suggested by identifying the chemical bonding with GO in X-ray photoelectron spectroscopy analysis. The reactivity of Al/CuO/GO composites is evaluated by comparing the maximum pressure and rate of the pressure increase of Al/CuO and Al/CuO/GO. The composites with a specific concentration of GO (10 wt%) demonstrate a well-dispersed mixture in hexane solution without phase separation.

• 청정기술
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• 제10권1호
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• pp.37-45
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• 2004

본 연구는 섬유산업에서 많이 사용되고 있는 주요염료인 분산성, 반응성, 산성염료를 대상으로 일반적인 수질오염항목인 COD, T-N, TOC, color, SS, TDS, conductivity 등을 분석하여 각각의 염료용액의 성상을 비교 분석하였고, NF막을 투과시켰을 경우 투과 flux와 배제율이 염료용액 종류에 따라서 어떻게 다른 양상을 나타내는지를 연구하였다. 결과적으로, 염료종류별 화학적 성질 및 구조적인 차이에 의하여 염료용액의 용해도 및 유기물부하 등이 달라짐을 알 수 있었고, 특히, 분산성 염료와 반응성염료는 이들 화학적 성질의 차이가 매우 현격하게 달라서 투과 flux 감소현상과 유기물, color, 부유물 및 용존 고형물, 이온성 물질 등의 배제율이 다른 양상을 보임을 알 수 있었다. 반응성염료 용액은 분산성염료 용액에 비하여 투과 flux는 높지만, TDS의 배제율이 낮은 반면, 분산성염료 용액은 부유성 고형물 농도가 높아 투과 flux가 낮고, 유기물질의 배제율이 낮은 특성을 나타낸다.

• 대한불안의학회지
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• 제10권1호
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• pp.3-10
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• 2014

Reactive disorder is a group of diagnosis with a definitely known etiology and whose etiological factor is essential to the diagnosis. In DSM system, such reactive disorders are listed as adjustment disorder, acute stress disorder, brief psychotic disorder with marked stressor and posttraumatic stress disorder (PTSD). However, a growing number of individuals is suffering from a prolonged feeling of embitterment after exceptional negative life events and this condition could be diagnosed neither PTSD nor adjustment disorder nor depressive disorder in the context of DSM-IV diagnostic system. This clinical condition can be described as 'posttraumatic embitterment disorder' (PTED). PTED is a reactive disorder triggered by exceptional, though normal negative life events such as conflict in the workplace, unemployment, death of a relative, divorce, severe illness, or experience of loss or separation. The common feature of such events is that they are experienced as unjust, as a personal insult, accompanied by psychological violation of basic beliefs and values. The central psychopathological response pattern in PTED is a prolonged feeling of embitterment. In particular, the core emotion of embitterment can lead to the rejection of treatment. Therefore, "wisdom therapy" as a new treatment approach specifically designed for PTED has been developed. It is assumed that many patients suffering from PTED are often misunderstood and misdiagnosed. This review would help to introduce PTED into the clinical field in psychiatry.

• 분석과학
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• 제24권4호
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• pp.298-303
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• 2011

셀레늄은 인체의 필수영양소로써 환경에서 또한 많은 관심을 가지고 있는 원소이다. 셀레늄은 자연수에서 주로 +4가의 selenite ($SeO_3^{-2}$)와 +6가의 selenate ($SeO_4^{2-}$)로 용해되어 있는데, 이들의 독성 및 화학적 성질은 매우 다르다. 따라서 자연수에서 셀레늄의 거동을 이해하기 위해서는 이들 두 화학종을 분리하는 것이 필요하다. 기존에 알려진 알루미나 충전 컬럼과 이온크로마토그래피를 이용한 selenite와 selenate의 분리방법들은 silicate 때문에 자연수에 직접 적용하기가 곤란하였다. 따라서 마그네타이트가 용액의 pH에 따라 selenite와 selenate를 흡착하는 정도가 다르므로 마그네타이트가 충전된 컬럼을 이용하여 이들의 분리를 수행한 결과, 성공적으로 분리할 수 있었다. 아울러 자연수에 존재하는 다른 음이온들 중에서 silicate는 selenite의 흡착을 방해하므로 silicate의 농도를 고려하여 충분한 양의 마그네타이트를 사용하여야만 한다.

• 공업화학
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• 제31권2호
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• pp.164-171
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• 2020

석탄계 활성탄을 사용한 Reactive Red 120 (RR 120) 염료의 흡착특성을 활성탄의 양, pH, 초기농도, 접촉시간 및 온도를 흡착변수로 사용하여 조사하였다. 등온흡착평형관계는 Langmuir 식이 Freundlich 식보다 더 잘 맞았다. 흡착 메카니즘은 균일한 에너지 분포를 가진 단분자층 흡착이 우세하다고 판단되었다. 평가된 Langmuir 분리계수(R_L = 0.181~0.644)로부터 이 흡착공정이 효과적인 처리영역(R_L = 0~1)에 속하는 것을 알았다. Temkin 식과 Dubinin-Radushkevich 식에 의해 구한 흡착에너지는 각각 E = 15.31~7.12 J/mol과 B = 0.223~0.365 kJ/mol로 흡착공정은 모두 물리흡착(E < 20 J/mol, B < 8 kJ/mol)으로 나타났다. 흡착속도실험결과는 유사 1차 반응속도식에 잘 맞았다. CGAC에 대한 RR 120 염료의 흡착반응은 온도가 올라갈수록 자유에너지 변화값이 감소하였기 때문에 온도 증가와 함께 자발성이 높아지는 것으로 나타났다. 엔탈피 변화(12.747 kJ/mol)는 흡열반응임을 알려주었다. CGAC에 의한 RR 120의 흡착반응의 등량흡착열은 9.78~24.21 kJ/mol로 물리흡착(< 80 kJ/mol)임을 밝혔다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.667-667
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• 2013

Optimizing morphology of the front surface with three dimensional structures (3D) in solar cell is essential element for not only effectivelight harvesting but also carrier collection and separation without the cost burden in process. We designed a three-dimensionally ordered front surface with wet chemical etching. Wet chemical etching is a proper way to have three dimensional structures. The method efficiently transmits the incident light at the front surface to a Si absorber and has competitive price in manufacturing when comparing with reactive ion etching (RIE) to have three dimensional structures. This indicates that optimized front surface with three dimensional structures by wet chemical etching will bring effective light management in solar cells.

• 한국세라믹학회지
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• 제52권6호
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• pp.489-496
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• 2015

In this study, novel $Ag_2Se$ sensitized $TiO_2$ nanocomposites were prepared by facile sonochemical assisted synthesis method. The as-prepared products were characterized by X-ray diffraction (XRD), Scanning electron microscopy (SEM) with energy dispersive X-ray (EDX) analysis, transmission electron microscopy (TEM), and N2 adsorption BET analysis. The as-prepared $Ag_2Se/TiO_2$ nanocomposites simultaneously possessed great adsorptivity for organic dyes and efficient charge separation properties. In the decolorization of rhodamine B, a significant enhancement in the reaction rate was observed for the $Ag_2Se/TiO_2$ nanocomposite compared to the cases of using pure P25 or $TiO_2$. The sonocatalysis activity was higher due to the greater formation of reactive radicals, as well as to the increase of the active surface area of the $Ag_2Se/TiO_2$ nanocomposite.

• Parasites, Hosts and Diseases
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• 제50권2호
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• pp.181-183
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• 2012

The author reported previously on separation of the outer tegument of the spargana (plerocercoids of Spirometra mansoni) using high concentration of urea solution. To determine which layer of the tegument is separated by this method, an electron microscopic analysis has been processed in this study. It was confirmed that the basement layer of the tegument is separated from the parenchyme of the sparganum. In addition, the antigenicity of the separated outer tegument against the human sparganosis patient sera was evaluated. Numerous antigenic proteins, including 16 and 55 kDa proteins, were noticed in the separated tegument; however, there were no diagnostic 31/36 kDa molecules in this tegument. The molecules reactive with the patient sera in the tegument are to be characterized in future studies.

• 조명전기설비학회논문지
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• 제28권4호
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• pp.21-28
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• 2014

Daily use characteristics of apparent power supplied to distribution transformer can be separated into two different time zone of waking hours and sleeping hours. In sleeping hours, using amount of power is decreasing. The actual curve of power seemed to be quite similar to this kind of separation. Inserting a condenser into a circuit in each different time zone led to maximize power factor of the transformer. The compensating condenser's on/off time is controlled by hysteresis circuit utilizing op amp and power factor of the transformer was improved from 0.945 to 0.999. As a result, the average of current reduction was 2.53A per hour of transformer.