• Korean Chemical Engineering Research
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• v.55 no.1
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• pp.60-67
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• 2017

In this study, we performed surface modification of biodegradable microcrystalline cellulose (MCC) to use as a filler in polyethylene (PE) composite in food packaging application. We modified MCC surface with (3-trimethoxysilylpropyl)diethylenetriamine (TPDT) silane coupling agent, which has one primary amino group and two secondary amino groups per molecule, to introduce amino groups with a carbon dioxide adsorption capability in MCC. Effects of each of the reaction conditions such as amount of TPDT introduced, swelling time, reaction temperature, and reaction time on surface modification degree of MCC were investigated by changing a variety of above reaction conditions. The amount of TPDT grafted on MCC surface and formation of chemical bonds were confirmed by Fourier transform infrared spectroscopy (FT-IR), elemental analysis (EA), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA) and solid state $^{29}Si$ nuclear magnetic resonance (NMR) spectroscopy. We confirmed increase of grafted amount of TPDT on MCC with increasing reaction time, reaction temperature, and amount of introduced TPDT.

• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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• 1994.07a
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• pp.23-24
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• 1994

본 연구는 성숙과의 저장중에 세포벽분해효소가 세포벽을 분해해서 물성의 변화를 유발함으로 일어나는 과실의 연과가 품질과 저장성의 저하 뿐만 아니라 영양적, 경제적 손실을 초래한다는 점을 고려하여 대추의 성숙중에 일어나는 연화현상을 연구하고자 성숙에 따른 경도, 세포벽분해효소의 활성, 세포벽 다당류 pectin질, 비섬유성 중성당 및 조직의 변화를 조사하였다. 경도는 대추의 숙성에 따라 감소하였고, polygalacturonase와 $\beta$-galactosidase의 활성은 각각 변색기와 완숙기에 나타난 이후 급격히 증가하였다. 세포벽 다당류인 pectin질과 알칼리 지용성 hemicellulose는 완숙기가지 증가햐였으나 cellulose는 완숙기에 산가용성 hemicellulose와 cellulose를 제외한 세포벽 다당류의 함량은 다소 감소하였다. 대추의 세포벽 비섬유성 중성당으로 rhamnose, arabinose, xylose, mannose, galactose, glucose가 동정되었고, 성숙동안에 pectin질에서는 arabinose, mannose, galactose와 총 비섬유성 중성당의 함량이 감소하였고, 산가용성 hemicellulose에서는 xylose와 mannose가 뚜렸하게 증가하였으나 중성당은 변화없었으며, 알칼리 가용성 hemicellulose에서는 성숙에 따른 변화가 거의 없었다. pectin질의 경우 수용성 pectin, EDTA 용해성 pectin 및 총 pectin은 성숙중에 증가하는 경향이있으나 불용성 pectin은 감소하는 경향이였으며 과숙기에는 불용성 psctin EDTA용해성 pectin 및 총 pectin의 함량은 모두 현저히 감소하였다. 대추의 성숙중 조직에서는 pectin질로 구성된 중충의 붕괴현상이 뚜렸하게 나타났다.발이 절실히 필요한 실정이다. 이러한 배경으로 본 강연에서는 효소적갈변 저해제의 개발과 그들의 식품가공에의 적용 현환 및 화장품, 의약품으로의 응용에 대해 설명하고자 한다.L주에 비해 S주는 수정후 용과가 더 심하다. 9) 화분관의 행동은 수정력과 완전히 일치된다. 즉 L-selfing, $L{\times}L$, S-selfing, $S{\times}S$등의 부적법 수분에서는 화분관은 화주의 미중에서 정지되지만 $L{\times}S$, $S{\times}L$,에서는 수분 약 40-50분 후이면 화분관은 자방까지 도달된다. 10) S주는 웅본으로 오인되어 있지만 인위적법수분을 하면 수정력이나 화분관의 행동은 L주에서와 동일하다. 11) S화분은 완전하지만 L화분은 약 70%가 내용공허한 Adortive pollen 이다. 12) L화분중 나머지 30%도 S화분에 비해서 염색도가 낮은것이 많고 S화분 같이 농염되는 것은 극히 소수이다. 13) 본장물은 분화가 고도로 진행된 전형적인 이형예작물이여 마치 Dimorphism 에서 Dioecious 에로 이행되는 수가 있다는 것을 표시하는 증거가 되는 것 같다. 다소 높은 산소농도 3%~5% 이산화탄소 농도 5~8%에서 저장하는 것이 효과적일 것으로 판단되었다.철쭉군목으로 대표되나 군단이 하의 군목들은 다소 차이를 보이는 것으로 나타났다. 중간상인이론의 수정이 필요하다고 본다.가\ulcorner 본 논문에서는 표면적 형태에도 불구하고 [-wh]의미의 겹의문사는 병렬적 관계의 합성어가 아니라 내부구조를 지니지 않은 단순한 단어(minimal $X^{0}$ elements)로 가정한다. 즉, [+wh] 의미의 겹의문사는 동일한 구성요 소를 지닌 병렬적 합성어([

• Clean Technology
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• v.23 no.2
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• pp.121-132
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• 2017

The increase of greenhouse gases and the concern of global warming instigate the development and spread of renewable energy and hydrogen is considered one of the clean energy sources. Hydrogen is one of the most elements in the earth and exist in the form of fossil fuel, biomass and water. In order to use hydrogen for a clean energy source, the hydrogen production method should be eco-friendly and economic as well. There are two different hydrogen production methods: conventional thermal method using fossil fuel and renewable method using biomass and water. Steam reforming, autothermal reforming, partial oxidation, and gasification (using solid fuel) have been considered for hydrogen production from fossil fuel. When using fossil fuel, carbon dioxide should be separated from hydrogen and captured to be accepted as a clean energy. The amount of hydrogen from biomass is insignificant. In order to occupy noticeable portion in hydrogen industries, biomass conversion, especially, biological method should be sufficiently improved in a process efficiency and a microorganism cultivation. Electrolysis is a mature technology and hydrogen from water is considered the most eco-friendly method in terms of clean energy when the electric power is from renewable sources such as photovoltaic cell, solar heat, and wind power etc.

• Fire Science and Engineering
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• v.33 no.4
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• pp.140-151
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• 2019

It is to assess the indoor air quality of the chemical hazardous materials exposed to the fire after firefighters returned to the fire scene. The research subject randomly selected four fire stations located in Seoul, Korea. Two fire stations were set up as control groups after the return of the firefighting activities at the actual fire scene, and two other fire stations were set up as control groups to measure the air quality of the room at normal levels regardless of the action. We conducted 24-hour monitoring for all fire accidents that occurred in Seoul Metropolitan using fire safety map computer system. Also, indoor air quality was measured immediately after homecoming if the experiment group was to be dispatched due to an accident of intermediate or larger scale. 11 hazardous substance items such as fine dust, formaldehyde, volatile organic compounds, PAH, VCM, acidity, asbestos, CO₂, NO₂, O₃ were measured according to the process test method. Three of 11 types of harmful substances exceeded domestic and foreign standards, and one of them was found to be close to foreign standards. In particular, total volatile organic compounds, carbon dioxide and sulfuric acids were 2.5 times, 2.2 times and 1.1 times higher than the standard. Also, for formaldehyde and sulfuric acid, it was measured higher in the control group than in the case group. This findings could be used in policies to improve indoor air quality in the fire station of the Seoul Metropolitan Government.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.2
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• pp.217-222
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• 1999

A squid viscera oil contains a high content of EPA, DHA, and other valuable polyunsaturated fatty acids. The extractions of squid viscera oil by supercritical carbon dioxide both with/without $3\%$ (v/v) ethanol were performed in a semicontinuous flow extractor at 8.3 to 13.8 MPa and 25 to $50^{\circ}C$. When ethanol was added to $SC-CO_2$, the extraction ratio of lipid increased. The extracts contained high content of unsaturated oils like DHA and EPA. The highest extraction yield of lipid from squid viscera oil extracted by supercritical carbon dioxide was obtained at 12.4 MPa and $40^{\circ}C$ with/without entrainer. The main fatty acids of squid viscera oil extracted by supercritical carbon dioxide were myristric acid (14:0), palmitic acid (16:0), palmitoleic acid (16:1), oleic acid (18:1), arachidic acid (20:0), eicosapentaenoic acid (20:5), and docosahaxaenoic acid (22:6).

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.5
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• pp.17-25
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• 2016

In this study, the air quality of underground and overground railway stations was evaluated focusing on the degree of influence of the outside air quality. The measured components were particulate matter ($PM_{10}$), carbon dioxide ($CO_2$), carbon monoxide (CO), nitrogen dioxide ($NO_2$), formaldehyde (HCHO), ozone ($O_3$), total airborne bacteria (TAB), total volatile organic carbon (TVOC), and Radon (Rn), which are included in the maintenance standards and recommended standards of the Indoor Air Quality Management Act. Also, the indoor/outdoor concentration ratios of $PM_{10}$, $NO_2$, and $O_3$ were calculated to estimate the influence of the outdoor air quality. The concentrations of $PM_{10}$ HCHO, TVOC, $NO_2$, and Rn in the underground stations were found to be higher than those in the overground stations. These results indicate that the (present) generation of contaminants are caused by the indoor source of the underground station. The ozone concentration of the overground stations was higher than that of the underground stations, which indicates that the outdoor ozone concentration influenced that of the overground stations directly. Thus, methods of improving the IAQ should take into consideration the types of contamination.

• Journal of the Korean Wood Science and Technology
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• v.42 no.3
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• pp.309-317
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• 2014

Harvested wood products (HWP) are known as products from the tree such as sawn wood, plywood, particle board, structural lumber, wooden interior material, wooden furniture, and paper products. Because carbon is locked up in the HWP until eventual end-use of HWP, HWP played a role as the carbon storage which has the effect of stabilizing the concentration of carbon dioxide in the atmosphere. For these reasons, the suggestion that it must admit the carbon storage effect of HWP has been constantly raised. In 2011, the 17th session of the Conference of the Parties (COP) to the United Nations Framework Convention on Climate Change (UNFCCC) which was held in Durban, South Africa, assigned "Production Approach" which targets only the HWP producted by using round wood of domestic forestry as a official method for carbon accounting. Therefore, it is necessary that each country has to determine the half-life of wood in order to correspond to the discussions and negotiations between countries in the future and to develop an inventory of product-specific domestic wood. In this study, some countries' examples of the methods and conditions for determining half-life of HWP were investigated, and it was tried to derive the factor and methodology to determine half-life span of domestic HWP appropriately.

• Fire Science and Engineering
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• v.23 no.6
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• pp.1-9
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• 2009

In this study, the burning behaviours of five different kinds of carpet samples covered with nylon, PP (polypropylene), PTT (poly(trimethylene terephthalate)), wool fabric and NW (nylon and wool) were evaluated by using the cone calorimeter having a radiant flux of 50kW/$m^2$. And the combustion gas toxicity was evaluated according to KS F 2271 test method. As a result of the cone calorimeter test (KS F ISO 5660-1), nylon carpet samples were ignited most easily. In ignition ability or initial flammability, NW carpet samples showed the highest value. In heat release rate (HRR), fire intensity, PP carpet samples were larger than any other samples. Nylon carpet samples were the highest smoke production rate, while N/W carpet samples the lowest. The following were in mass loss rates: NW > wool > nylon > PP > PTT. CO (carbon monoxide) was one of the most toxic gases released from the combustion. PTT carpet samples gave rise to the highest CO concentration, while NW carpet samples the lowest. In addition, PP carpet samples caused the highest $CO_2$ (carbon dioxide) concentration, while NW carpet samples the lowest. Toxicity of the gas produced from carpet samples was determined by the mouse stop motion, and it resulted in the fact that the combustion gas of PTT carpet samples was more toxic than that of any other samples.

• Journal of the Korean Recycled Construction Resources Institute
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• v.9 no.2
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• pp.223-228
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• 2021

The final disposal method for asbestos building materials is to be landfilled at a designated waste landfill in accordance with the Waste Management Act. However, it is difficult to secure a domestic designated waste landfill site to landfill the entire amount of asbestos waste, which is expected to emit more than 400,000 ton/year by 2044. In this study, a detoxification treatment was performed on a ceiling tex with a density of 1.0 to 1.2g/cm³ containing 3 to 7% of chrysotile, and it was used as a reinforcing fiber for extruded panels. It was confirmed that asbestos components were detoxified through the reaction process using 30% oxalic acid and carbon dioxide, and it was recognized that these detoxifying properties were maintained even after extrusion molding. However, it was found that milling to a fiber size of less than 1mm for complete detoxification of asbestos resulted in a decrease in reinforcing performance. Therefore, in the case of using detoxified asbestos fibers in the extrusion molding process, it is considered desirable to add fibers with a length of 5mm or more to improve the reinforcing performance.

• Journal of the Korean Recycled Construction Resources Institute
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• v.10 no.1
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• pp.117-123
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• 2022

Recently, due to COV ID-19, many people are spending most of their time indoors. So, there is a rising interest on the indoor air quality in the field of building construction. The main sources for the indoor air pollution are human indoors activity, building materials, living supplies and the polluted air from outdoor. The Korean government has designated 17 indoor air pollutants including fine dust, total airborne bacteria, fungi and carbon dioxide, etc.. Most people are always exposed to assorted bacteria and molds in our daily life, because indoor environment for human, moderate temperature are humidity, it is favourable to the growth of most of bacteria and fungi. Pine needles have an antibacterial effect against bacteria and fungi. In this study, the antibacterial activity against bacteria and fungi was tested by cement matrix using pine needle extract. As a result, the cement matrix using pine needle extract showed antibacterial activities against bacteria, but in the case of fungi, it did not show antifungal activity.