• Journal of the Korean Wood Science and Technology
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• 제46권2호
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• pp.189-201
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• 2018

Intumescent system is a highly effective flame retardant technology that takes advantage of the mechanism of foaming and carbonization. In order to materialize Intumescent system, it is necessary to use reinforcement material to improve the strength of the material. In this study, we used kenaf as a natural fiber to manufacture intumescent/EVA (ethylene vinyl acetate) composites to improve mechanical and flame retardant performance. Finally two materials with different particle shape are applied to one system. Therefore, the influence factors of the particles with different shapes on the composite material were analyzed based on the tensile test. For this purpose, we have used the tensile strength analysis model and confirmed that it can only act as a partial strength reinforcement due to weak binding force between the matrix and particles. In the combustion characteristics analysis using cone calorimeter and UL 94, the combustion characteristics were enhanced as the content of Intuemscent was increased. As the content of kenaf increased, combustion characteristics were strengthened and carbonization characteristics were weakened. Through the application of kenaf, it can be confirmed that elastic modulus improvement and combustion characteristics can be strengthened, which confirmed the possibility of development of environmentally friendly flame retardant materials.

• 전기학회논문지P
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• 제59권4호
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• pp.462-466
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• 2010

The purpose of this study is to evaluate the safety of a wire connector fabricated for the effective installation of a lighting fixture including its contact resistance, insulation resistance, withstanding voltage characteristics, etc., and to provide the basis for the analysis and judgment of PL(Product Liability) dispute by presenting a damage pattern due to a general flame and overcurrent. This study applied the Korean Standard (KS) for the incombustibility test of the connector using a general flame and performed an overcurrent characteristics test of the connector using PCITS (Primary Current Injection Test System). The contact resistance of the housing connector was measured using a high resistance meter and the insulation resistance was measured using a multimeter. In addition, a supply voltage of AC 1,500V for testing the withstanding voltage characteristics was applied to both ends of the connector. Measurement was performed on 5 specimens and the measured values were used as a basis for judgment. Since the connector is fabricated in the form of a housing, it can be connected and separated easily and has a structure that allows no foreign material to enter. In addition, since it has a structure that allows wires to be connected only when their polarity is identical, any misconnection that may occur during installation can be prevented. When the incombustibility test was performed by applying a general flame to the connector, it showed outstanding incombustibility characteristics and the blade and blade holder connected to the housing remained firmly secured even after the insulation sheath (PVC) was completely destroyed by fire. In addition, the mechanism of the damaged connecting wire showed a comparatively uniform carbonization pattern and it was found that some residual melted insulation material was attached to both ends. In the accelerated life test (ALT) to which approximately 500% of the rated current was applied, the connector damage proceeded in the order of white smoke generation, wire separation, spark occurrence and carbonization. That is, it could be seen that the connector damaged by overcurrent lost its own metallic color with traces of discoloration and carbonization. The contact resistance of the connector at a normal state was 2.164mV/A on average. The contact resistance measured after the high temperature test was 3.258mV/A. In addition, the insulation resistance after the temperature test was completed was greater than $10G\Omega$ and the withstanding voltage test result showed that no insulation breakdown occurred to all specimens showing stable withstanding voltage and insulation resistance characteristics.

• 공업화학
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• 제17권5호
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• pp.532-538
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• 2006

탄화 및 활성화 조건을 매개체로 여러 등급의 Polyacrylonitrile (PAN)계 ACF (ACF : Activated Carbon Fiber)를 제조하여 최적의 비표면적을 나타내는 활성화 공정을 알아보았고, 가장 큰 비표면적을 갖는 PAN계 ACF에 대한 표면특성 및 독성가스 등에 대한 흡착특성을 분석하였다. 시험결과 활성화 온도가 증가할수록 비표면적이 증가하고 탄화 온도가 감소할수록 비표면적이 감소하였고, $900^{\circ}C$로 15 min간 탄화한 후 $900^{\circ}C$로 30 min간 활성화 공정을 거친 ACF가 $1204m^2/g$의 가장 높은 비표면적을 나타내었고 요오드 및 테러용 독성가스에 대한 흡착 성능시험 결과 기존의 흡착제보다 우수하였다. 또한 선택적 흡착을 위한 기능성을 부여하기 위하여 기존의 금속염을 침적하는 방법을 대체하여 비교적 안정화된 금속나노입자(Ag, Pt, Cu, Pd)를 제조하여 첨착하였고 이에 대한 표면특성 및 $SO_{2}$에 대한 흡착특성을 분석하였다. 금속나노입자 첨착 ACF에 대한 $SO_{2}$ 흡착성능 시험결과 Ag, Pt, Cu 나노입자를 첨착한 ACF는 무첨착 ACF의 파과시간(326 sec)과 비교 할 때 크게 변함이 없었으나 Pd 나노입자를 첨착한 ACF는 파과시간이 925 sec로 $SO_{2}$ 흡착성능이 매우 우수함을 알 수 있었다.

• Carbon letters
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• 제28권
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• pp.24-30
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• 2018

Coke aggregates and carbon artifacts were produced to investigate the interactions of coke and pitch during the kneading process. In addition, the kneading ratio of the coke and binder pitch for the coke aggregates was controlled to identify the formation of voids and pores during carbonization at $900^{\circ}C$. Experiments and thermogravimetric analysis revealed that carbon yields were improved over the theoretical yield calculated by the weight loss of the coke and binder pitch; the improvement was due to the binding interactions between the coke particles and binder pitch by the kneading process. The true, apparent, and bulk densities fluctuated according to the kneading ratio. This study confirmed that an excessive or insufficient kneading ratio decreases the density with degradation of the packing characteristics. The porosity analysis indicated that formation of voids and pores by the binder pitch increased the porosity after carbonization. Image analysis confirmed that the kneading ratio affected the formation of the coke domains and the voids and pores, which revealed the relations among the carbon yields, density, and porosity.

• 공업화학
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• 제34권2호
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• pp.153-160
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• 2023

본 논문에서는 미이용 바이오매스로부터 바이오차를 생산하고 메틸렌블루 흡착 특성을 평가하였다. 바이오매스는 주로 셀룰로오스, 헤미셀룰로오스, 리그닌으로 구성되어 있으며 회분의 함량은 벌채부산물에서 가장 높았다. 탄화 온도가 증가할수록 탄화 수율은 감소하였으며, 수소와 산소 함량도 감소하였다. 반면, 탄소 함량은 증가하였다. 탄화 온도가 증가할수록 바이오차의 비표면적과 미세기공은 증가하였다. 바이오차 비표면적은 탄화 온도 600 ℃에서 가장 높았다(216.15~301.80 m² /g). 600 ℃에서 탄화한 바이오차를 이용하여 메틸렌블루 흡착 실험을 수행한 결과, 참나무, 벌채부산물, 사과 전정가지의 흡착 거동은 Freundlich model, 복숭아 전정가지는 Langmuir model에 적합하였다. 흡착 동역학에서 참나무와 복숭아 전정가지는 pseudo-first-order model, 벌채부산물과 사과 전정가지는 pseudo-second-order model에 적합하였다.

• 공업화학
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• 제34권6호
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• pp.608-612
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• 2023

탄소블록의 열전도도를 증가시키기 위하여 탄소블록 제조 공정 중 nano-diamond (ND)를 첨가하였다. 첨가된 ND는 탄화 과정에서 바인더 피치의 휘발로 인하여 생성된 탄소블록의 기공을 제어하였다. ND의 첨가는 코크스 및 바인더 피치의 혼련 공정에 추가하였으며, 성형, 탄화를 거쳐 탄소블록을 제조하였다. 첨가된 ND의 양이 증가할수록 탄소블록의 ND 비율이 증가하였다. 첨가된 ND는 탄화 과정에서 바인더 피치의 휘발로 인하여 발생하는 가스의 이동 통로 역할을 하여 탄소블록의 밀도를 높이고, 기공률을 감소시켰다. ND의 첨가를 통하여 높아진 밀도, 낮아진 기공률, ND의 높은 열전도도를 통하여 탄소블록의 열전도도를 향상시킬 수 있었다.

• 한국화재소방학회논문지
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• 제32권2호
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• pp.48-56
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• 2018

본 논문은 가속열화에 따른 IV절연전선 피복의 과전류 특성에 관한 연구이다. IV절연전선 피복의 절연열화를 위해 가속수명시험 모형 중 아레니우스 방정식을 이용한 가속열화실험을 진행하여 등가수명 0년, 10년, 20년, 30년, 40년 실험시료를 제작하였다. 그 후 실험시료 대상으로 허용전류 100%~500% 과전류를 인가하여 전선피복에서 최초 연기 및 탄화 발생시간을 측정하였고, 등가수명이 증가함에 따라 최초 연기 및 탄화 발생시간이 감소하는 것으로 나타났다. 세부적으로 과전류 270%에서 등가수명 0년을 기준으로 등가수명 40년의 전기화재 위험성이 3.2배 증가하였다. 또한, 과전류 255% 및 260% 인가 시 등가수명 40년에서만 탄화가 발생하여 가속열화에 따른 화재위험성이 비약적으로 증가하는 것으로 나타났다. 추가적으로 FT-IR과 SEM을 이용하여 IV절연전선 피복의 등가수명에 따른 특성 및 표면 변화의 차이를 확인하였다.

• 환경위생공학
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• 제22권1호
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• pp.17-27
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• 2007

This study was conducted the adsorption experiment way of organic wastewater (BOD, COD, TOC, T-N, T-P) by changing the carbonization temperature and the size of adsorbent to examine the adsorption capacity of Korean traditional charcoal which has similar characteristics to activated carbon of organic pollutants. Also, it was performed the basic experiment for pH and inorganic materials. As a result of observing Korean traditional charcoal with has the greatest inorganic contents which are the important factor of chemical adsorption. As the carbonization temperature was better high temperature charcoal than law temperature charcoal to adsorption capacity of pollutant and as the particle was minute (D size : $3.35mm{\sim}2.0mm$), it was most effective. The result of adsorption experiment of organic wastewater show that the elimination ratio of pollutants by bamboo high temperature charcoal was found as BOD(82.1%), COD(91.7%), TOC(52.4%), T-N(66.6%), T-P(83.2%) and it has most excellent adsorption capacity of organic pollutants.

• Carbon letters
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• 제10권4호
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• pp.329-334
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• 2009

In this work, the effect of carbon nanofibers (CNFs) addition on physicochemical characteristics of CNFs-reinforced epoxy matrix nanocomposites was studied. Poly(amide imide) solutions in dimethylformamide were electrospun into webs consisting of $250{\pm}50$ nm fibers which were used to produce CNFs through stabilization and carbonization processes. As a result, the CNFs with average diameter of $200{\pm}20$ nm were obtained after carbonization process. The nanocomposites with CNFs showed an improvement of thermal stability parameters and fracture toughness factors, compared to those of the specimen without CNFs, which could be probably attributed to the higher specific surface area and larger aspect ratio of CNFs, resulting in improving the mechanical interlocking in the nanocomposites. Also, the applied external loading can effectively transfer to CNFs because strong interactions are resulted between the epoxy matrix and the CNFs.

• 한국세라믹학회지
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• 제34권8호
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• pp.825-833
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• 1997

Silicon carbide films were deposited by low pressure chemical vapor deposition(LPCVD) using MTS(CH3SICl3) in hydrogen atmosphere on (100) Si substrate. To prevent the unstable interface from being formed on the substrate, the experiments were performed through three deposition processes which were the deposition on 1) as received Si, 2) low temperature grown SiC, and 3) carbonized Si by C2H2. The microstructure of the interface between Si substrates and SiC films was observed by SEM and the adhesion between Si substrates and SiC films was measured through scratch test. The SiC films deposited on the low temperature grown SiC thin films, showed the stable interfacial structures. The interface of the SiC films deposited on carbonized Si, however, was more stable and showed better adhesion than the others. In the case of the low temperature growth process, the optimum condition was 120$0^{\circ}C$ on carbonized Si by 3% C2H2, at 105$0^{\circ}C$, 5 torr, 10 min, showed the most stable interface. As a result of XRD analysis, it was observed that the preferred orientation of (200) plane was increased with Si carbonization. On the basis of the experimental results, the models of defect formation in the process of each deposition were compared.