• Journal of Animal Environmental Science
• /
• v.18 no.2
• /
• pp.99-110
• /
• 2012

The purpose of the study is to collect basis data for to establish standard administrative processes of liquid fertilizer treatment. From this survey we could make out the key point of each step through a case of effective liquid manure treatment system in pig house. It is divided into six step; 1. piggery slurry management step, 2. Solid-liquid separation step, 3. liquid fertilizer treatment (aeration) step, 4. liquid fertilizer treatment (microorganism, recirculation and internal return) step, 5. liquid fertilizer treatment (completion) step, 6. land application step. From now on, standardization process of liquid manure treatment technologies need to be develop based on the six steps process.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.13 no.11
• /
• pp.5610-5614
• /
• 2012

Performance of catalyst was studied with various operating conditions for selective catalytic reduction of $NO_x$ with $NH_3$. It is confirmed that catalysts containing Mn and Cu have a good efficiency in the usage of oxygen by the $H_2$-TPR analysis. In the case of catalyst #1, $NO_x$ conversion was decrease with the increase of reaction temperature. But in the case of catalyst #2, $NO_x$ conversion was increased and then remained constant with the increase of reaction temperature. This phenomenon is due to the difference of the $NH_3$ oxidation of both catalysts.

• KSBB Journal
• /
• v.20 no.5 s.94
• /
• pp.338-340
• /
• 2005

Covalent modification of a protein with polyethylene glycol (PEG) has become one of the most widely used and well established drug enhancement strategies in the biopharmaceutical industry. The general benefits enjoyed by PEGylation, such as prolonged serum half-lives or reduced immunogenicity in vivo, are well known. By now the PEGylation process has been performed with purified proteins, and it is required to recover the desired PEGylate by a multi-step purification process. The ultimate aim of our research is to develop an integrated process of PEGylation and in vitro refolding starting with inclusion body material. For this, we investigated the feasibility that a protein could be PEGylated under a denaturing condition and also the PEGylated proteins could be refolded correctly. Using lipase as a model protein, we found that it was PEGylated in the presence of 8M urea and that the PEG molecules covalently attached to lipase did not appear to hinder its refolding.

• Polymer(Korea)
• /
• v.34 no.1
• /
• pp.52-57
• /
• 2010

The low viscous epoxy resin(bisphenol F) with carboxylic acid as the reductants was introduced for high performance and reliability in the ACA with a low melting point alloy filler system. The curing characteristics of the epoxy resin and temperature dependant viscosity characteristic of epoxy resin at the melting temperature of LMPA were investigated by dynamic mode of differential scanning calorimetry (DSC) and rheometer, respectively. Based on these thermo-rheological characteristics of epoxy resin and LMPA, the optimum process system was designed. In order to remove the oxide layer on the surface of LMPA particle, three different types of carboxyl acid-based reductant were added to the epoxy resin. The wetting angles were about $18^{\circ}$ for carboxypropyldisilioxane, and $20.3^{\circ}$ for the carboxy-2-methylethylsiloxane, respectively.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2008.11a
• /
• pp.209-209
• /
• 2008

$BaTiO_3$는 대표적인 강유전체 재료로서 적층형 세라믹 콘덴서 (MLCC), PTC thermistor, resonator 등 다양한 분야에서 사용되고 있다. $BaTiO_3$ 기본조성으로 하는 PTC 써미스터는 온도가 올라감에 따라 저황이 높아지는 특성을 가지고 있으며, 이러한 PTCR 특성은 작동되는 큐리온도에 따라 그 적용이 달라진다. PTCR 소자는 소결온도, 소결분위기, 불순물, 첨가제 등의 제조공정상의 인자들과 기공률, 결정립 크기 등이 복합적으로 작용해 PTCR 특성에 영향을 미치기 때문에 제조하기에 무척 까다로운 소자로 알려져 있다. 하지만 우수한 특성을 지닌 PTCR 소자를 제조하기 위하여 새로운 조성개발이 이루어지고 있으며, 전기적 특성 개선, 재현성 확보, 제조원가 절감 등의 측면에서 새로운 공정개발이 이루어지고 있다. 본 연구에서는 Sm을 첨가한 $BaTiO_3$계 재료의 PTCR 특성에 미치는 Ti/Ba ratio 등의 변화에 따른 영향을 조사하고 공기 중과 환원분위기 중에서 소결된 시편의 차이점과 재산화 처리에 따른 PTC 특성에 미치는 영향을 R-T 측정으로 고찰하였다. 본 조성은 환원 분위기에서 소결할 경우 그 미세구조는 Ti/Ba ratio비가 높을 때 grain size가 커져 상온 비저항을 낮출 수 있었다. Sm 첨가로 상온 비저항값은 낮출 수 있었으나 공기 중에서 재산화 처리하더라도 jumping ratio$(R_{max}/R_{25^{\circ}C})$는 Ti/Ba ratio와 거의 무관한 것으로 분석되었다.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2013.08a
• /
• pp.72.1-72.1
• /
• 2013

광촉매 활용 기술은 수질 및 대기 중의 난분해성 오염 물질 처리 등의 환경 분야에서부터 항균 및 초친수성 기능을 활용한 소재 분야, 그리고 태양광을 이용한 물분해 수소 제조 및 이산화탄소의 전환 등의 인공 광합성 연구 분야까지 그 응용분야가 대단히 넓은 기술이다. 본 강연에서는 이러한 광촉매의 반응 원리와 대표적인 응용분야인 환경 정화 분야 및 에너지 분야에서의 광촉매 기술의 활용, 그리고 현재 광촉매 관련 연구 분야의 주요 관심사 및 미래 성장을 위한 과제 등을 포괄적으로 다루고자 한다. 광촉매 반응은 반도체의 따간격 에너지 흡수에 따라 전자와 정공(+전하를 가진 전자와 같은 거동을 하는 입자)가 발생한 뒤에 일어나는 계면에서의 전자전달 반응을 기초한다. 발생한 정공과 전자는 각각 산화와 환원 반응을 유발하며 이러한 산화, 환원반응을 통해 다양한 분야로의 응용이 가능하다. 환경 정화 분야의 경우, 정공이 물 혹은 공기 속에 존재하는 수분과 반응하여 생성되는 OH 라디칼 ($OH{\cdot}$)의 강력한 산화력을 주로 이용하게 된다. OH 라디칼에 의한 다양한 난분해성 유기물질의 산화분해 반응을 활용하여 고도처리공정이 가능하게 되며, 수계 난분해성 유기오염물질의 제거뿐만 아니라 대기 중에 존재하는 VOCs, 악취물질 등의 분해도 가능하며, 아울러 바이러스나 박테리아와 같은 세균을 제거할 수 있는 것으로 알려져 있다. 한편, 물 분해 수소제조 및 이산화탄소의 전환과 같은 에너지 분야 응용의 경우, 전도대의 전자를 활용한 환원반응에 기초한다. 앞서 언급한 다양한 응용분야에서 활용될 수 있는 광촉매의 종류 또한 매우 다양하며, 이사화티탄(TiO2)는 대표적인 고효율 상용 광촉매이다. 아울러, 원하는 응용 분야에서의 광활성이 높은 새로운 광촉매의 제조 및 평가가 꾸준히 진행되고 있으며, 그 가운데 태양광의 가장 많은 영역을 차지하고 있는 가시광 활성을 갖는 광촉매 개발에 관한 연구가 활발히 수행되고 있다. 이에, 현재까지 개발된 다양한 가시광 광촉매 시스템에 대한 소개 및 각 광촉매 응용분야에서 최근 새롭게 대두되고 있는 이슈들에 대하여 중점적으로 고찰하고자 한다.

• Composites Research
• /
• v.34 no.5
• /
• pp.277-282
• /
• 2021

Graphene oxide can be reduced to graphene under supercritical fluid condition even without using a specific reducing agent or applying a high thermal process. In this study, a process for converting graphene oxide into graphene was studied under supercritical fluid conditions in methanol and ethanol solvents. When the structure of asprepared graphene was analyzed by using FE-SEM and XRD, the reduction of graphene oxide in supercritical fluid condition was more affected by the change of solvent than other variables such as concentration of graphene oxide and reaction time. The use of ethanol showed better results for the reduction than the use of methanol. The graphene prepared in this study was mixed with epoxy resin up to 20 wt.% to make composites, and the thermal conductivity of the composites were analyzed. Thermal conductivity of the composite increased proportionally with graphene loadings. The graphene prepared in supercritical ethanol condition was more effective on the thermal conductivity of the composite.

• Composites Research
• /
• v.34 no.2
• /
• pp.108-114
• /
• 2021

Graphene flakes are generally mass-produced by converting graphene oxide into reduced graphene oxide using chemical or thermal reduction. These graphene flakes can be stacked to form a free-standing graphene paper, which can be used for various applications. However, a graphene paper lacks stretchability, which hinders its application in stretchable devices. In this work, we introduced wrinkles in a graphene paper to make it stretchable. A graphene paper fabricated by vacuum-filtering a graphene dispersion was placed on a pre-stretched adhesive film. When the pre-stretched adhesive film returned to the original state, the graphene paper was wrinkled. The effect of the pre-stretching and wet condition of the graphene papers was experimentally investigated by using scanning electron microscopy. In addition, we observed the change of the period of the wrinkles in the graphene paper depending on the pre-stretching.

• Resources Recycling
• /
• v.28 no.6
• /
• pp.87-95
• /
• 2019

This study investigated the effect of process variables for smelting of recovery of valuable metal in the sludge generated from PCB. The moisture and organics in the sludge was removed by preteatment process. The phase equilibria and slag system was selected by thermodynamic phase calculation program and the process variable of pyro-metallurgical process such as reductant. Smelting temperature and holding time for a recovery of valuable metal was studied.

• Applied Chemistry for Engineering
• /
• v.26 no.1
• /
• pp.104-110
• /
• 2015

It is known that polymer concretes are 8~10 times more expensive than ordinary Portland cement concretes; therefore, in the production of polymer concrete products, it is very important to reduce the amount of polymer binders used because this occupies the most of the production cost of polymer concretes. In order to develop a technology for the reduction of polymer binders, smooth and spherical aggregates were prepared by the atomizing technology using the oxidation process steel slag (electric arc furnace slag, EAFS) and the reduction process steel slag (ladle furnace slag, LFS) generated by steel industries. A reduction in the amount of polymer binders used was expected because of an improvement in the workability of polymer concretes as a result of the ball-bearing effect and maximum filling effect in case the polymer concrete was prepared using the smooth and spherical atomized steel slag instead of the calcium carbonate (filler) and river sand (fine aggregate) that were generally used in polymer concretes. To investigate physical properties of the polymer concrete, specimens of the polymer concrete were prepared with various proportions of polymer binder and replacement ratios of the atomized reduction process steel slag. The results showed that the compressive strengths of the specimens increased gradually along with the higher replacement ratios of the atomized steel slag, but the flexural strength showed a different maximum strength depending on the addition ratio of polymer binders. In the hot water resistance test, the compressive strength, flexural strength, bulk density, and average pore diameter decreased; but the total pore volume and porosity increased. It was found that the polymer concrete developed in this study was able to have a 19% reduction in the amount of polymer binders compared with that of the conventional product because of the remarkable improvement in the workability of polymer concretes using the spherical atomized oxidation steel slag and atomized reduction steel slag instead of the calcium carbonate and river sand.