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        검색결과 4,677

        1061.
        2017.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Microstructure, electric, and thermal properties of the Ta-Cu composite is evaluated for the application in electric contact materials. This material has the potential to be used in a medium for a high current range of current conditions, replacing Ag-MO, W, and WC containing materials. The optimized SPS process conditions are a temperature of 900oC for a 5 min holding time under a 30 MPa mechanical pressure. Comparative research is carried out for the calculated and actual values of the thermal and electric properties. The range of actual thermal and electric properties of the Ta-Cu composite are 50~300W/mk and 10~90 %IACS, respectively, according to the compositional change of the 90 to 10 wt% Ta-Cu system. The results related to the electric contact properties, suggest that less than 50 wt% of Ta compositions are possible in applications of electric contact materials.
        4,000원
        1062.
        2017.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study we manufacture a Ni-Cr-B-Si +WC/12Co composite coating layer on a Cu base material using a laser cladding (LC) process, and investigate the microstructural and mechanical properties of the LC coating and Ni electroplating layers (reference material). The initial powder used for the LC coating layer is a powder feedstock with an average particle size of 125 μm. To identify the microstructural and mechanical properties, OM, SEM, XRD, room and high temperature hardness, and wear tests are implemented. Microstructural observation of the initial powder and LC coating layer confirm the layer is composed mainly of γ-Ni phases and WC and Cr23C6 carbides. The measured hardness of the LC coating and Ni electroplating layers are 653 and 154 Hv, respectively. The hardness measurement from room up to high temperatures of 700°C result in a hardness decrease as the temperature increases, but the hardness of the LC coating layer is higher for all temperature conditions. Room temperature wear results show that the wear loss of the LC coating layer is 1/12 of the wear level of the Ni electroplating layer. The measured bond strength is also greater in the LC coating than the Ni electroplating.
        4,000원
        1063.
        2017.10 구독 인증기관·개인회원 무료
        제조물책임법은 제품의 제조, 설계, 표시상의 결함으로 인해 사용자의 생명이나 신체에 피해나 손실이 발생할 경우 제조물의 결함과 그로 인한 피해 사실이 입증되면 제조업자 등이 손해배상책임을 지게 하는 제도이다. 제조물책임법의 시행으로 기업은 제품의 안전성 확보와 만약에 발생할 수 있는 제품 사고를 대응하는 활동을 체계적으로 수립하는 노력이 필요하다. 그렇지만 실제로 기업이 제조물 책임 대응활동을 얼마나 체계적으로 예방하고 대응할 수 있는가를 확인할 수 있는 제도는 아직 미흡한 상태이다. 따라서 본 연구에서는 제조기업의 제조물책임 대응수준 평가제도 도입에 대한 소비자의 인식과 제도의 필요성을 조사하여 객관적이고 체계적인 평가제도로 도입할 수 있도록 연구결과를 기초자료로 제공하는데 목적이 있다.
        1064.
        2017.10 구독 인증기관·개인회원 무료
        The purpose of this research isto make improve productivity through process improvement without expensive capital investment in a small scale mold manufacturer. The target company which is selling sand mold casting products employs many foreigners, and 50% of factory workers worked by the periphery of a specific manufacturing sector were difficult to communicate smoothly on site. Also, the company has the customized production method which production and delivery time are constant each month. However, the company's situation is getting harder since the order volume of existing suppliers has decreased and profit has reduced. So, we decided that the company needs new customers and overseas markets in the long run but to improve the process without facility investment in the short term is important task. We improved the process, created the standard of work for foreign workers, and improved the working environment by eliminating the on-site risk factors that the staff could not perceive. The results were as follows. The productivity has improved by 1.5 times. Training by work standards has shortened the OJT time of new workers and efficient working methods have become standard. Improvement of the work environment has improved the job satisfaction of workers and enabled long-term service of workers in the mold industry where labor shortage is serious.
        1065.
        2017.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        As the consumption of wheat has increased recently, the number of people who have digestive problems resulting from gluten in wheat has also increased. Teff has an attractive nutritional profile, as it not only gluten-free but also high in dietary fiber, protein, iron, and calcium. Seven samples were prepared for this study. The quality characteristics of gluten-free noodles were evaluated based on pH, salinity, water absorption, turbidity, color, texture properties, tensile strength, and SEM. The pH value was the highest in TF100 with a pH of 6.66 and the lowest in the control with a pH of 6.42. Salinity showed no significant difference among all samples, and it ranged from 0.02~0.04% (p<0.05). Water absorption was the highest in TFX with a value of 66.11%, and the lowest in the control with a value of 44.81%. Turbidity showed no significant difference among all samples, and it ranged from 0.14~0.21 O.D. (p<0.05). While the lightness and yellowness values decreased with an increase in teff flour content, the redness value tended to decrease. The color difference value was the highest in the sample group without gluten. Based on the texture profile analysis, the hardness was highest in the control with a value of 46.74 N and lowest in TF100 with a value of 18.34 N. The springiness showed no significant difference among all samples. The cohesiveness was highest in the control with a value of 0.92 N. The chewiness decreased with an increase in teff flour content. Although the control with gluten had the highest tensile strength at 3.42 kg/cm2, TFX had considerable tensile strength at 2.30 kg/cm2. This study demonstrated the processability of gluten-free noodles using teff flour.
        4,000원
        1066.
        2017.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Palatability and texture analysis of nine Korean rice cultivars were investigated to select the most appropriate rice variety for the cooked-rice processing. The rice cultivars studied consisted of Samkwang, Seonpum, Wolbaek, Andabyeo, Dasan-1, Ilpum, Haiami, Jungsanggold and Chindle. They revealed the moisture, protein, amylose and starch contents of 10~12, 5~6, 12~19, and approximately 90%, respectively. Among the evaluated rice varieties, WB exhibited the lowest amylose content (12.7%) and Jungsanggold the next (17.2%). In the rapid-visco analyzer test, Jungsanggold, Chindle, Wolbaek and Seonpum revealed a low value of final and setback viscosities than other varieties. Using a toyo meter analyzer, Chindle, Haiami, Samkwang were selected as having high toyo palatability values, while Dasan-1, Wolbaek and Andabyeo revealed low values. Toughness and adhesiveness of all nine cooked rice varieties were highest in Jungsanggold, Chindle and Ilpum. Also, palatability of cooked rice was highest in the following order: Chindle (80.03) > Samkwang (76.21) > Jungsanggold (74.08). The results of this study suggest that Chindle may be effectively used to produce processed cooked rice.
        4,000원
        1067.
        2017.10 구독 인증기관·개인회원 무료
        국내 도로의 총 연장은 매년 증가하고 있으며, 도로의 노후화는 점차 높아지고 있다. 한국건설기술연구원에 따르면 20년 이상 노후된 도로 포장 중속국도는 ‘12년 기준 400km, 일반국도는 4,703km이며 ’22년에는 고속국도는 3,322km, 일반국도는 8,660km로 노후화에 따른 유지보수 대상 도로의 증가는 불가피한 설정이다. 따라서, 본 연구에서는 고성능 친환경 도로보수용 상온아스콘과 제조시스템의 개발에 관한 것으로 가장 기본이 될 수 있는 바인더의 개발하였다. 바인더의 개발단계에서 수용성바인더와 지용성바인더 두 가지를 를 바인더 선정을 위한 기초연구를 실시하였다. 기존의 도로보수용 상온아스콘의 보관사용을 위한 필수적인 첨가제인 가소제의 선정에 있어서 환경적으로 보다 무해한 재료를 사용하였다. 사용된 가소제의 역할을 하는 재료는 저 비등점 재료와 고 비등점 재료를 사용한다. 저 비등점과 고 비등점 가소제는 제품의 양생시간을 조절하기 위해서 사용되는 가소제의 역할을 하는 재료로서, 여름철과 겨울철에 따라서 사용량이 조절된다. 본 기소제는 연구과제의 개발단계의 두 가지 바인더에 공동으로 사용이 가능하다. 고성능의 제품 발현을 위해서 사용된 개질첨가제는 수용성 바인더와 지용성 바인더를 사용하였다. 이러한 개질첨가제는 혼합물을 제조할 때 여러 가지 방법을 사용하여 바인더 혹은 혼합물내에 분산성을 고려하여 투입방식을 달리하여 사용하였다. 국내 골재가 음이온으로 구성되어 있는 것을 감안하여 양이온유제를 사용하여 개발하였다. 양이온 유제를 사용한 제품의 골재와의 코팅테스트에서는 코팅율은 양호한 상태이었으나, 도로보수용으로 사용하기 위한 저장 및 보관을 위한 양생시간의 조절은 유화제로 조절하기에는 무리가 있어 단기간에 양생이 되는 현상이 발생되었다. 수용성 바인더를 이용한 도로보수용 상온아스콘의 저장 보관을 위해서 상기에서 언급한 두 가지의 가소제를 양생조절용으로 첨가하였으며 고성능을 부여하기 위해서 상기에서 언급한 수용성용의 개질첨가제를 사용하여 기초시험을 실시하였으나 포장지에 상온아스콘을 보관하는 과정에서 바인더에 함유된 수분이 포장지 내부에 유출되는 현상으로 포장지의 파손에 영향을 주는 결과를 초래하였다. 결과적으로 도로보수용 상온아스콘을 포장지에 보관하는 용도에는 수용성바인더는 부적합 한 결과를 나타냈다. 지용성 바인더는 골재의 종류와 상관없이 혼합성능이 우수하게 나타났다.또한 고성능을 부여하기 위한 개질첨가제와의 상용성도 우수한 것으로 판단되었으며, 포장지내의 보관 시 사소한 트러블도 발생되지 않아 바인더로서 적합한 것으로 판단된다.
        1068.
        2017.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        식물 및 동물성 단백질 유래 펩타이드 형태의 단백질 가수 분해물들은 항산화, 고혈압 완화, 면역조절, 진통완화 및 항균작용 등 생리활성이 있는 것으로 알려져 왔다. 본 연구는 연산오계란 단백질 가수 분해물을 Ultrafiltration를 이용하여 HDS(분획되지 않은 가수 분해물), 1 kDa, 5 kDa, 10 kDa, 50 kDa로 분획된 기능성 펩타이드의 DPPH radical scavenging activity, superoxide anion radical scavenging activity, hydroxyl radical scavenging activity 및 Fe2+ chelation ability을 평가하였다. 그 결 과 DPPH radical scavenging activity 최대값은 1 kDa(70.83 %), hydroxyl radical scavenging activity 최대값은 5 kDa (47.01 %), superoxide anion radical scavenging activity 최대값은 5 kDa(40.57 %), Fe2+ chelation ability 최대값은 5 kDa(29.87 %)로 나타났다. Ultrafiltration를 이용하여 fractionation된 단백질 가수 분해물의 항산화 저해 능력 IC50 평가하였다. 그 결과 HDS의 최대값은 superoxide anion radical scavenging activity(IC50, 5.42 mg/ml)이고, 1 kDa의 최대값은 Fe2+ chelation ability(IC50, 1.67 mg/ml)이고, 5 kDa의 최대값은 Fe2+ chelation ability(IC50, 2.09 mg/ml)이고, 10 kDa의 최대값은 Fe2+ chelation ability(IC50, 2.61 mg/ml)이고, 50 kDa의 최대값은 Fe2+ chelation ability(IC50, 4.53 mg/ml)이 다. 그러므로 본 연구 결과를 바탕으로 5 kDa를 이용하여 오계란 단백질에서 분획한 펩타이드는 항산 화 기능성 식품소재로서 활용할 가치가 높을 것으로 기대한다.
        4,000원
        1069.
        2017.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        내열성이 우수하며, 태양광 모듈의 유리 표면에 방담성(antifogging) 및 방오성(antifouling) 을 동시에 부여하여 효율을 향상시키기 위한 친수성 코팅액을 제조하기 위해 초친수성과 우수한 방담효 과를 나타내는 Tween 20과 데카플루오로부탄과 폴리에틸렌글리콜 성분으로 구성된 불소계면활성제 수 용액에 방오성 부여를 위하여 나노실리카를 분산하였다. 고온 처리에서 나노실리카의 함량에 따른 방담 효과는 모든 코팅액이 우수하였으나, 방오 효과는 나노실리카의 함량이 6 wt%일 때부터 나타났다. 불소 계면활성제의 함량이 증가할수록 초기 접촉각이 증가하며 방담 효과도 500회 wiping까지 잘 유지되었 다. 방오 효과 역시 불소계면활성제의 함량에 상관없이 우수하여 불소계면활성제의 적절한 첨가량은 0.1 wt%이상 이면 충분하였다. AFM 결과로부터 불소계면활성제가 0.1 wt%에서 0.3 wt%가 첨가된 경우 코팅 표면의 프랙탈구조가 확실히 나타나 방오성 향상에 기여하였다. 코팅된 유리의 투과도는 불소계면 활성제가 0.1 wt% 첨가된 TL-1의 경우가 가장 높았으며 더 많은 양의 불소계면활성제를 첨가할 경우 오히려 투과도 향상은 미미하였다. 이러한 결과는 앞의 AFM 결과에서 나타난 표면 조도가 높으며 프랙 탈구조 형성도 잘 일어난 TL-1 코팅액의 결과와 잘 일치하는 것이다.
        4,200원
        1070.
        2017.09 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        An optimum route to fabricate oxide dispersion strengthened ferritic superalloy with desired microstructure was investigated. Two methods of high energy ball milling or polymeric additive solution route for developing a uniform dispersion of Y2O3 particles in Fe-Cr-Al-Ti alloy powders were compared on the basis of the resulting microstructures. Microstructural observation revealed that the crystalline size of Fe decreased with increases in milling time, to values of about 15-20 nm, and that an FeCr alloy phase was formed. SEM and TEM analyses of the alloy powders fabricated by solution route using yttrium nitrate and polyvinyl alcohol showed that the nano-sized Y-oxide particles were well distributed in the Fe based alloy powders. The prepared powders were sintered at 1000 and 1100 oC for 30 min in vacuum. The sintered specimen with heat treatment before spark plasma sintering at 1100 oC showed a more homogeneous microstructure. In the case of sintering at 1100 oC, the alloys exhibited densified microstructure and the formation of large reaction phases due to oxidation of Al.
        4,000원
        1071.
        2017.09 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Surface morphology and optical properties such as transmittance and haze effect of glass etched by physical and chemical etching processes were investigated. The physical etching process was carried out by pen type sandblasting process with 15~20 μm dia. of Al2O3 media; the chemical etching process was conducted using HF-based mixed etchant. Sandblasting was performed in terms of variables such as the distance of 8 cm between the gun nozzle and the glass substrate, the fixed air pressure of 0.5bar, and the constant speed control of the specimen stage. The chemical etching process was conducted with mixed etching solution prepared by combination of BHF (Buffered Hydrofluoric Acid), HCl, and distilled water. The morphology of the glass surface after sandblasting process displayed sharp collision vestiges with nonuniform shapes that could initiate fractures. The haze values of the sandblasted glass were quantitatively acceptable. However, based on visual observation, the desirable Anti-Glare effect was not achieved. On the other hand, irregularly shaped and sharp vestiges transformed into enlarged and smooth micro-spherical craters with the subsequent chemical etching process. The curvature of the spherical crater increased distinctly by 60 minutes and decreased gradually with increasing etching time. Further, the spherical craters with reduced curvature were uniformly distributed over the etched glass surface. The haze value increased sharply up to 55 % and the transmittance decreased by 90 % at 60 minutes of etching time. The ideal haze value range of 3~7 % and transmittance value range of above 90 % were achieved in the period of 240 to 720 minutes of etching time for the selected concentration of the chemical etchant.
        4,000원
        1072.
        2017.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A self-propelled turner was developed to produce mushroom compost at low costs and high efficiency, and the uniformity of compost produced by an excavator, compost mixer, and self-propelled turner was compared. The material of the compost was mixed with rice straw and chicken manure at a dry weight ratio of 3:1. After the final turning, internal temperature distribution, water content of the compost pile, ash ratio, and uniformity of the compost pile were examined. After the compost was completed, the water content was 69.9 ± 0.54%, 72.1 ± 0.15%, and 74.5 ± 0.82%, respectively. The length of rice straw was 47.5 ± 15.4 cm, 24.9 ± 10.1 cm, and 31.0 ± 10.6 cm, respectively. The ash content in the dry weight of each compost was 25.0 ± 6.2%, 33.6 ± 4.2%, and 28.2 ± 1.1%, respectively. The deviation in the length of rice straw was affected by the linear velocity of the spinner in the compost mixer and the self-propelled turner, which were 21.5 m/sec and 9 m/sec, respectively. As a result, the most uniform mushroom compost was produced by the self-propelled turner.
        4,000원
        1073.
        2017.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 팽이버섯 수확 후 배지를 첨가하여 호밀 사일리지 제조 시 팽이버섯 수확 후 배지를 에너 지원으로서 사용하기 위하여 in vitro 반추위 발효실험이 수행되었다. 공시 사일리지는 출수기의 호밀 에 팽이버섯 수확 후 배지 첨가비율(0%, 20%, 40%, 60%)에 따라 제조하여 6주일간 발효시켰다. In vitro 배양액 제조를 위한 반추위액은 농후사료와 볏짚을 40:60의 비율로 급여한 반추위 cannula가 시 술된 Holstein 수소 2두로 부터 채취하였다. In vitro 실험은 발효시간대를 3, 6, 9, 12, 24 및 48시간 으로 설정하고, 각 처리구별로 3반복으로 발효특성과 건물소화율을 측정하였다. In vitro 배양액의 pH 는 발효시간이 길어짐에 따라 낮아지는 경향이었으며, 48시간 경과 시에는 버섯수확 후 배지 60% 첨가 구가 타 처리구에 비해 유의적(p<0.05)으로 낮았다. 미생물 성장율은 배양시간이 경과함에 따라 증가 하는 경향이었으며, 발효 48시간 경과 시에는 버섯수확 후 배지 20% 첨가구가 타 처리구에 비해 유의 적으로(p<0.05) 높았다. Gas발생량은 48시간 발효 시에 대조구가 타 처리구에 비해 유의적(p<0.05)으 로 높았다. 건물소화율은 버섯수확 후 배지의 첨가비율이 높을수록 높았는데, 발효 24시간 및 48시간에 는 R-60구가 처리구 중에서 가장 높았으며(p<0.05), 대조구에서는 전 발효기간 동안 건물소화율이 현 저히 낮은(p<0.05) 상태에 있었다. In vitro 반추위내 발효실험의 결과와 버섯수확 후 배지의 활용성을 고려할 때, 호밀사일리지 제조 시 팽이버섯 수확 후 배지 첨가비율을 원물기준으로 60%수준이 가장 긍 정적인 것으로 나타났다. 향후 대사시험이나 사양시험을 통하여 가축사료로써의 최적 대체 비율을 규명 해야 할 것으로 사료되는 바다.
        4,200원
        1074.
        2017.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study was to identify the observable symptoms of musculoskeletal disease from electronic components manufacturing workers who involved in many repetitive tasks and to provide the basic data for the prevention and management. The survey was conducted on 721 people from 15 April, 2013 to 17 May, 2013 by selfrecording type. The results of the study are as follows. First, symptom complaints based on different body parts are in following order, waist was 12.9%, shoulder was 10.5%, neck was 7.4%, hand/wrist/finger was 7.4%, leg/foot was 4.4%, arm/elbow was 2.8%, and 21.9% of the respondents showed symptoms in more than one body part. Sex, age, marital status, work experience, work intensity, and past accident experience were statistically significant. Second, in the job stress evaluation, all male and female workers were below the median of Korean workers in all of 8 categories. the higher the scores for lack of job autonomy, the higher the symptom complaints of musculoskeletal disease. In the case of patients complain observable symptoms of musculorskeletal disease, they should receive proper outpatient treatment, various programs such as stretching by body parts, setting up a desirable working posture, switching to cyclical work, should b developed as much as possible.
        4,000원
        1075.
        2017.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        As the global uncertainty of manufacturing has increased and the quality problem has become global, the recall has become a fatal risk that determines the durability of the company. In addition, as the convergence of PSS (product-service system) product becomes common due to the development of IT convergence technology, if the function of any part of hardware or software does not operate normally, there will be a problem in the entire function of PSS product. In order to manage the quality of such PSS products in a stable manner, a new approaches is needed to analyze and manage the hardware and software parts at the same time. However, the Fishbone diagram, FTA, and FMEA, which are widely used to interpret the current quality problem, are not suitable for analyzing the quality problem by considering the hardware and software at the same time. In this paper, a quality risk assessment model combining FTA and FMEA based on defect rate to be assessed daily on site to manage quality and fishbone diagram used in group activity to solve defective problem. The proposed FTA-FMEA based risk assessment model considers the system structure characteristics of the defect factors in terms of the relationship between hardware and software, and further recognizes and manages them as risk. In order to evaluate the proposed model, we applied the functions of ITS (intelligent transportation system). It is expected that the proposed model will be more effective in assessing quality risks of PSS products because it evaluates the structural characteristics of products and causes of defects considering hardware and software together.
        4,200원
        1076.
        2017.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Volatile organic compounds (VOCs) are a source of air pollution and are harmful to both human health and the environment. In this study, we fabricated polyurethane/rare earth (PU/RE) composite nanofibrous membranes via electrospinning with the aim of removing VOCs from air. The morphological structure of PU/RE nanofibrous mats were investigated using FE-SEM, EDX, and XRD experimental analyses. A certain amount of RE (up to 50 wt% compared to PU pellets) particles could be loaded on/into PU fibers. The PU nanofiber containing 50 wt% RE powder had the smallest fiber diameter of 356 nm; it also showed the highest VOCs absorption capacity compared with other composite membranes, having an absorption capacity about 3 times greater than pure PU nanofibers. In addition, all of the PU/RE nanofibrous membranes readily absorbed styrene the most, followed by xylene, toluene, benzene and chloroform. Therefore, the PU/RE nanofibrous membrane can play an important role in removing VOCs from the air, and its development prospects are impressive because they are emerging materials.
        4,000원
        1077.
        2017.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        요즘 건물 내에서의 생활이 많아진 현대인에게 실내공기의 질은 매우 중요한 개념이고, 새롭게 생각을 해 보아야 하는 문제이다. 실내공기의 질은 실내공기의 온도, 습도 등으로 결정이 된다. 그리고 실내공기 개선을 위해서는 에너지 소비 가 심하다는 단점이 있다. 그리하여, 전열교환을 이용하여 이러한 문제를 해결하려는 방법에 대한 연구가 활발히 이루어지고 있다. 따라서, 본 연구에서는 전열교환 분리막 적용을 위하여, poly(styrene-ethylene-butylene-styrene) 고분자에 친수성 치환기 인 암모늄을 도입하여 아민화된 SEBS 고분자를 합성하였고, 합성고분자에 대한 특성평가를 진행하였다. 암모늄을 도입하기 위하여 클로로메틸화 반응과 아민화 반응을 통하여 합성을 진행하였다. 결과적으로 합성고분자는 반응용제의 함량이 높아질 수록 함수율, 이온교환용량이 증가하였고, 전열교환 분리막에서 중요한 투습도 또한 증가함을 확인할 수 있었다.
        4,000원
        1078.
        2017.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        There has been much interest in recycling electronic wastes in order to mitigate environmental problems and to recover the large amount of constituent metals. Silver recovery from electronic waste is extensively studied because of environmental and economic benefits and the use of silver in fabricating nanodevices. Hydrometallurgical processing is often used for silver recovery because it has the advantages of low cost and ease of control. Research on synthesis recovered silver into nanoparticles is needed for application to transistors and solar cells. In this study, silver is selectively recovered from the by-product of electrodes. Silver precursors are prepared using the dissolution characteristics of the leaching solution. In the liquid reduction process, silver nanoparticles are synthesized under various surfactant conditions and then analyzed. The purity of the recovered silver is 99.24%, and the average particle size of the silver nanoparticles is 68 nm.
        4,000원
        1079.
        2017.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Fe3O4/Fe/graphene nanocomposite powder is synthesized by electrical wire explosion of Fe wire and dispersed graphene in deionized water at room temperature. The structural and electrochemical characteristics of the powder are characterized by the field-emission scanning electron microscopy, X-ray diffraction, Raman spectroscopy, field-emission transmission electron microscopy, cyclic voltammetry, and galvanometric discharge-charge method. For comparison, Fe3O4/Fe nanocomposites are fabricated under the same conditions. The Fe3O4/Fe nanocomposite particles, around 15-30 nm in size, are highly encapsulated in a graphene matrix. The Fe3O4/Fe/graphene nanocomposite powder exhibits a high initial charge specific capacity of 878 mA/g and a high capacity retention of 91% (798 mA/g) after 50 cycles. The good electrochemical performance of the Fe3O4/Fe/graphene nanocomposite powder is clearly established by comparison of the results with those obtained for Fe3O4/Fe nanocomposite powder and is attributed to alleviation of volume change, good distribution of electrode active materials, and improved electrical conductivity upon the addition of graphene.
        4,000원
        1080.
        2017.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, Fe-Cu-C alloy is sintered by spark plasma sintering (SPS). The sintering conditions are 60 MPa pressure with heating rates of 30, 60 and 9oC/min to determine the influence of heating rate on the mechanical and microstructure properties of the sintered alloys. The microstructure and mechanical properties of the sintered Fe-Cu-C alloy is investigated by X-ray diffraction (XRD) and field-emission scanning electron microscopy (FE-SEM). The temperature of shrinkage displacement is changed at 450oC with heating rates 30, 60, and 90oC/min. The temperature of the shrinkage displacement is finished at 650oC when heating rate 30oC/min, at 700oC when heating rate 60oC/min and at 800oC when heating rate 90oC/min. For the sintered alloy at heating rates of 30, 60, and 90oC/min, the apparent porosity is calculated to be 3.7%, 5.2%, and 7.7%, respectively. The hardness of the sintered alloys is investigated using Rockwell hardness measurements. The objective of this study is to investigate the densification behavior, porosity, and mechanical properties of the sintered Fe-Cu-C alloys depending on the heating rate.
        4,000원