• Food Science and Biotechnology
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• 제15권1호
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• pp.5-12
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• 2006

Degradation performance of environmentally friendly plastics that can be disintegrated by combination of sunlight, microbes in soil, and heat produced in landfills was evaluated for use in industries. Two multi-degradable master batches (MCC-101 and MCC-102 were manufactured, separately mixed with polyethylene using film molding machine to produce 0.025 mm thick films, and exposed to sunlight, microbes, and heat. Low- and high-density polyethylene (LDPE and HDPE) films containing MCC-101 and MCC-102 became unfunctional by increasing severe cleavage at the surface and showed high reduction in elongation after 40 days of exposure to ultraviolet light. LDPE and HDPE films showed significant physical degradation after 100 and 120 days, respectively, of incubation at $68{\pm}2^{\circ}C$. SEM images of films cultured in mixed mold spore suspension at $30^{\circ}C$ and 85% humidity for 30 days revealed accelerated biodegradation on film surfaces by the action of microbes. LDPE films containing MCC-l01 showed absorption of carbonyls, photo-sensitive sites, at $1710\;cm${-1}$ when exposed to light for 40 days, whereas those not exposed to ultraviolet light showed no absorption at the same frequency. MCC-101-based LDPE films showed much lower $M_w$ distribution after exposure to UV than its counterpart, due to agents accelerating photo-degradation contained in MCC-101.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.631-631
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• 2013

Battery has major drawbacks including its size and life expectancy, and environmental problem. As an alternative, energy harvesting is emerging as a potential solution to replace battery along with more energy-efficient IT devices. The idea of harnessing energy from our living environment is sustainable, semi-permanent, and eco-friendly. Also, unlike battery, energy harvester does not require much space to store energy. Therefore, energy harvesting can provide a better source of power for small, portable, and wireless devices. Among various ways of harvesting energy from our surroundings, triboelectricity is chosen due to its potential to be miniaturized, and efficient. Triboelectric effect occurs as two different materials with different polarity of charge separation come into contact through friction, and then become separated so that electric potential difference is achieved. In this research, such characteristic of triboelectricity is used as a way to convert ambient mechanical energy into electric energy.Series of recent researches have shown promising results that the triboelectric energy harvester can be simple and cost effective. However, sufficient electricity level required to operate mobile devices has not yet been achieved.In this research, our group focuses on the design and optimization of triboelectric energy harvesting device to enhance its output. By using maskless lithography to pattern Kapton film and silicon substrate, which is used as a mold for PDMS thin layer, and sputtering metal electrodes on each side, we fabricate and demonstrate different designs of triboelectric energy harvester that utilizes the contact electrification between a polymer thin film and a metal thin foil. In order to achieve optimized result, the output voltage and current are measured under diverse conditions, which include different surface structure and pattern, material, and the gap between layers.

• 한국약용작물학회지
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• 제24권3호
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• pp.183-190
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• 2016

Background: This study determined the effects of mulching, an environment friendly organic cultivation method, on antioxidant compound contents and growth in Codonopsis lanceolata, commonly known as Deodeok. Methods and Results: C. lanceolata was treated by mulching with several different methods (a non-woven fabric, biodegradable film, or rice husks) and also treated with hand weeding. A non-treatment plot was used as a control. The growth and levels of weed control in C. lanceolata were better in plants cultivated under mulching treatments (non-woven fabric, biodegradable film, and rice husks) than in those under non-mulching treatments (hand weeding and non-treatment). The contents of antioxidant compounds, such as total flavonoids, phenolics, and anthocyanins, were highest under the biodegradable film treatment, followed by the non-woven fabric treatment, rice husks treatment hand weeding, and non-treatment. There were identifiable differences in DPPH and ABTS activity in comparison to antioxidant compound content by solvent fractions. Mulching treatments resulted in higher DPPH scavenging activity in water and ethyl ether fractions and ABTS scavenging activity in n-butanol fractions than in other fractions, as opposed to hand weeding and non-treatment groups, although total activity of DPPH and ABTS did not increase with mulching treatments. Conclusions: Mulching C. lanceolata with biodegradable film and non-woven fabric is an effective method for improving plant growth and inhibiting the occurrence of weeds as well as for increasing antioxidant compound content and altering antioxidant activity.

• 한국콘텐츠학회논문지
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• 제15권2호
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• pp.177-186
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• 2015

본 논문은 21세기에 접어들어 다품종 소량생산으로 변화하고 있는 추세에 맞추어 가구디자인 분야가 이바지 할 수 있는 방향성을 3D프린팅을 이용한 가구디자인 제작 사례를 분석함으로써 제시하는 것에 목적을 두고 있다. 본 논문은 3D 프린팅으로 제작된 가구 및 조명의 사례를 3가지 분류로 분석하였다. 첫째 3D프린팅 방식과 재료의 연관성에 따른 분류, 둘째 3D프린팅 가구디자인의 8가지 조형적 특징에 따른 분류, 셋째 실용성, 사용성, 내구성에 따른 기존 가구디자인과 3D 프린팅 가구 디자인의 경쟁력 비교분석이다. 본 연구를 통해 얻어진 가구디자인 분야에서 3D 프린팅 기술이 가져다주는 경쟁력은 다음과 같다. 첫째, 개인 취향에 맞춘 다품종 소량생산이 가능하다. 둘째, 디지털을 통한 가구의 전송, 운송이 편리해 졌다. 셋째, 가구디자인 생산에 변혁을 가져다준다. 넷째, 3D 프린팅과 사물인터넷의 융합을 통해 스마트가구디자인 분야로의 발전 가능성이 있다. 다섯째, 지속가능한 친환경 가구디자인이 용이해진다.

• 산업경영시스템학회지
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• 제32권2호
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• pp.120-131
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• 2009

Most world-leading companies are aware that Environment and Health and Safety Issues are critical to the product quality and sustainable growth of their company. Environment-friendly efforts are seen in almost all aspects of business operations in an advanced nation. The Extended Producer Responsibility(EPR) and EU Directive on Waste Electric and Electronic Equipment(WEEE) attempt to tackle the growing quantity of WEEE by making producers responsible for the costs of the collection and recycling of their products at the End-of-Life(EOL). To implement the RFID-based integration system for EOL household electric appliances, such as washing machines and refrigerators, we analyzed the process of collecting, recovering, and recycling the EOL products returned from the distribution points. Furthermore, we proposed a soon-to-be process using the RFID-based integration system in the metropolitan recycling center(MRC). This soon-to-be process model is composed of RFID tags, readers, ALEs, applications and several devices. Through the introduction of the RFID-based integration system, we are expecting to see increasing traceability and real-time management for EOL products from customers, and also improvements in valuable reusable materials(VRM) produced from recycling processes.

• 접착 및 계면
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• 제14권3호
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• pp.135-145
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• 2013

환경친화형 반도체 봉지재로서 할로겐 화합물 등의 첨가형 난연제를 혼합하지 않고 자기소화성을 발현시키는 에폭시수지 조성물에 관해 연구하였다. 탄화수소계 방향족 공액이중결합의 구조를 갖는 에폭시수지와 페놀수지의 반응물에서 자기소화성을 갖는 낮은 연소열이 확인되었다. 본 연구에서는 탄화수소계 방향족 공액이중결합에 헤테로원자계 이중결합인 아조메틴기를 도입하여 더욱 낮은 연소열을 확인할 수 있었다. 낮은 연소열의 결과는 높은 반응열과 열전이온도 그리고 빠른 반응성과 관련이 있으며 아조메틴기의 헤테로원자 구조의 영향 때문으로 보인다.

• International Journal of Advanced Culture Technology
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• 제3권2호
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• pp.100-109
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• 2015

Environmental problems from petroleum-based plastic wastes have been rapidly increasing in recent years. The alternative solution is focus on the development of environmental friendly plastic derived from renewable resource. Poly(lactic acid) (PLA) is a biodegradable polymer synthesized from biomass having potential to replace the petroleum-based non-degradable polymers utilizations. PLA can be synthesized by two methods: (1) ring-opening of lactide intermediate and (2) direct polycondensation of lactic acid processes. The latter process has advantages on high yields and high purity of polymer products, materials handling and ease of process treatments. The polymerization process of PLA synthesis has been widely studied in a laboratory scale. However, the mass scale production using direct polycondensation of lactic acid has not been reported. We have investigated the kinetics and scale-up process of direct polycondensation method to produce PLA in a pilot scale. The order of reaction is 2 and activation energy of lactic acid to lactic acid oligomers is 61.58 kJ/mol. The pre-polymer was further polymerized in a solid state polymerization (SSP) process. The synthesized PLA from both the laboratory and pilot scales show the comparable properties such as melting temperature and molecular weight. The appearance of synthesized PLA is yellow-white solid powder.

• Composites Research
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• 제24권6호
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• pp.18-24
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• 2011

대기압 화염 플라즈마(APFP) 및 에폭시 실란(ES) 표면처리 한 실리카($V_f=40%$) 강화 고무복합재료의 기계적 특성에 대한 실험적 연구를 수행하였다. 고무복합재료의 인장강도는 평균 입자경이 감소할수록 크게 증가하였고, 평균 입자경 $2.2{\mu}m$일때, 기지(2.52MPa)에 비해 1.4배 증가하였다. 또한 APFP 및 EP의 처리로 인장강도가 각각 8.8~13.3%, 9.9~12.5% 향상되었다. 평균 입자경이 $26.6{\mu}m$일 때, 고무복합재료의 인장탄성율은 기지(0.88MPa)에 비해 2배 증가하였고, APFP 및 EP의 처리로 인장 탄성율이 각각 15.6~22.8%, 21.1~25.8% 증가되었다. 기존의 실란 커플링제 처리방법은 유기용제의 사용 등의 몇 가지 단점을 가지고 있지만, APFP 처리법은 기계적 특성을 향상시키는데 빠르고, 경제적이며 친환경적인 방법이라 판단된다.

• Transactions on Electrical and Electronic Materials
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• 제10권6호
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• pp.222-226
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• 2009

The objective of this study is to share multimedia contents included in existing digital devices and to solve the problems of an increase in installation fees and non-environmentally friendly interiors. This study designed a new digital signal transmitter and receiver using power line transmission and HDMI in order to solve the problems in the existing systems. The transmitter and receiver designed in this study used an AD9867BCPZ PLC chip in which the transmission came from digital signals originating in a PC, and the system architecture was configured so that the outputs signals were connected to a TV from the receiver. The experiment was implemented by adding a Video Test Generator, a USBPre external sound card, and Smaart Live 6 for analyzing the characteristics of the configured system. In the video test results, it was verified that communication was actively implemented, and the image quality showed a constant level from the measurement of the captured video. In the case of the sound, it was verified that more than 90% of the sound signals were normally transmitted and received from the examination of their phases and magnitudes. Thus, the performance of the system designed in this study was verified, which leads to the resolution of some of the problems found in current digital devices.

• 한국환경생태학회지
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• 제22권2호
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• pp.145-151
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• 2008

본 연구는 북한산국립공원 탐방로상 도입된 보행시설물에 대한 탐방객 평가를 통해 국립공원 탐방로의 효율적 유지관리를 위한 관련 기초 정보 제공을 목적으로 수행되었다. 이를 위해 북한산국립공원 도봉지구 탐방로를 이용한 탐방객 250명을 대상으로 응답자직접기입방식을 적용하여 설문조사를 실시하였다. 연구결과, 도봉 주능선 도봉지구에 설치된 6개의 보행 시설에 양적 질적 상태는 비교적 양호한 것으로 조사되었다. 목재데크 시설, 목재난간 시설, 돌깔기 시설이 기타 시설에 비해 경관조화성, 자원보전성, 이용편의성 측면에서 긍정적으로 평가되었다. 결국 국립공원에서의 보행시설물의 도입에 있어 친자연적인 소재의 도입은 필수적이며 자원보호와 탐방편의의 기능과 함께 경관조화라는 시각적 효과의 고려가 필요하다.