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        검색결과 1,253

        321.
        2018.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        최근 우수한 유연성과 화학적 안정성 등을 가진 고분자 수지와 우수한 기계적 성질 등을 나타내는 무기 재료로 이루어진 나노 복합 시스템으로써 유-무기 하이브리드 코팅 필름에 관한 연구가 활발히 진행되고 있다. 아크릴레이트 단량체로써 사용된 o-phenylphenoxyethyl acrylate (OPPEA)는 1.576의 높은 굴절률을 나타내고, Bisphenol A ethoxylate diacrylate (BAEDA)는 굴절률은 낮지만 경화된 고분자의 경도를 향상시킨다. 또한, 무기 소재로써 사용된 지르코니아는 산화지르코늄으로써 우수한 내구성과 광학특성 등을 나타낸다. 본 연구에서는 광학 특성을 향상시키기 위한 목적으로 아크릴레이트 단량체 중 BAEDA의 함량을 조절하여 필름을 제조한 뒤 연필 경도계와 아베굴절계를 이용하여 광학 특성 변화를 확인하였고, UV-vis spectrophotometer을 이용해 투과도를 비교하여 최적의 조건을 확립하였다. 그리고 실란 커플링제인 γ-methacryloxypropyltrimethoxysilane (MPS)를 사용하여 지르코니아를 소수화 처리하여 아크릴레이트 단량체에 대한 분산성을 향상시키고, 개질 전후의 물에 대한 분산성 변화를 조사하여 물에 대한 친화력이 감소하였음을 확인하였고, FT-IR ATR spectrophotometer를 통해 MPS에 의해 도입된 1716 cm-1에서의 에스터 C=O 결합 peak의 존재를 통해 MPS에 의한 지르코니아 표면의 개질 반응이 진행되었음을 확인하였다. 또한, 지르코니아의 표면에 도입된 규소 원자의 존재는 X 선 형광법을 이용하여 확인하였다. 그리고 화학적으로 개질된 지르코니아를 아크릴레이트 단량체에 도입하여 광경화 필름을 제조하였을 때, 굴절률은 아크릴레이트 자체 필름보다 1.2% 향상되었음을 확인하였고, SEM/EDS mapping 분석을 통해 PET 필름에 코팅된 개질 후 지르코니아가 아크릴레이트 코팅층에 균일하게 분포되어 있음을 알 수 있었다.
        4,200원
        322.
        2018.09 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Nitrogen is a serious contaminant in natural gas because it decreases the energy density. The natural gas specification in South Korea requires a N2 content of less than 1 mol%. Thus, cost-effective N2 removal technology from natural gas is necessary, but until now the only option has been energy-intensive processes, e.g., cryogenic distillation. Using porous materials for the removal process would be beneficial for an efficient separation of CH4/N2 mixtures, but this still remains one of the challenges in modern separation technology due to the very similar size of the components. Among various porous materials, metal-organic frameworks (MOFs) present a promising candidate for the potential CH4/N2 separation material due to their unique structural flexibility. A MIL-53(Al), the most well-known flexible metal-organic framework, creates dynamic changes with closed pore (cp) transitions to open pores (ops), also called the ‘breathing’ phenomenon. We demonstrate the separation performance of CH4/N2 mixtures of MIL-53(Al) and its derivative MIL-53-NH2. The CH4/N2 selectivity of MIL- 53-NH2 is higher than pristine MIL-53(Al), suggesting a stronger CH4 interaction with NH2.
        4,000원
        323.
        2018.07 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A citric acid functionalized graphene oxide nanocomposite was successfully synthesized and the structure and morphology of the nanocatalyst were comprehensively characterized by Fourier transform infrared spectroscopy, energy-dispersive X-ray analysis, X-ray diffraction patterns, atomic force microscopy images, scanning electron microscopy images, transmission electron microscopy images, and thermogravimetric analysis. The application of this nanocatalyst was exemplified in an important condensation reaction to give imidazole derivatives in high yields and short reaction times at room temperature. The catalyst shows high catalytic activity and could be reused after simple work up and easy purification for at least six cycles without significant loss of activity, which indicates efficient immobilizing of citrate groups on the surface of graphene oxide sheets.
        4,000원
        324.
        2018.07 구독 인증기관·개인회원 무료
        Certification labeling is a system which confirms the quality and appropriateness of pr oducts according to the standard set. It is usually evaluated by the third party to assure being reliability. Certification labeling can be used as one of the important sources of i nformation when consumers evaluate the products. Especially, certification labeling gi ves customers trust and confidence about products because the label can be the signali ng that the quality of the products is good. Although certification labeling influences p urchase decision making, many consumers do not trust the labels because of insufficie nt information of certification and distrust in the certifications. As consumers are becoming increasingly concerned about environment and wellbeing, manufacturers are turning a convention product into the production of a sustain able product. Sustainable certification can be environmental cues to evaluate a sustain able product based on the categorization inference. The aim of this research is the inte raction effect among sustainable cues on purchase intention. Consumers tend to perceive organic label of products as high-price. Thus, although they concern environment and well-being, they tend to purchase conventional products more than an organic product. In addition, an organic label can have a positive influence on perceived risk, and then perceived risk may affect purchase intention. However, the product with organic label including traceability may have a negative impact on perceived risk. Therefore, perceived risk can mediate the relationship between the interaction between organic label of products and traceability and purchase intention.
        326.
        2018.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Two sewage treatment facilities were selected to identify odor emission characteristics, focusing on volatile organic compounds (VOCs) and sulfur compounds. The complex odor, 5 kinds of sulfur compounds and 23 kinds of VOCs were analyzed from gas and sludge storages. Hydrogen sulfide was detected in the highest concentration and had the highest odor quotient among the odorous compounds monitored in this study, demonstrating that the contribution of hydrogen sulfide to the complex odor reached up to 90%. For VOCs, the overall contribution to the complex odor was not critical but VOCs can sufficiently trigger an odorous sensation because the sum of the odor quotient reached up to 2.89.
        4,000원
        327.
        2018.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This paper is a review on the treatment of volatile organic compounds using absorbents. Volatile organic compounds (VOCs) are carbon-based compounds with a boiling point ranging from 50℃ to 250℃. VOCs have been considered as contributors of photochemical smog and global warming as well as hazards to human health. VOCs can be removed by a variety of methods, including those that are destructive (incineration, catalytic oxidation, and biodegradation) and non-destructive (adsorption, absorption, and condensation). The removal performance of VOCs in the gas phase is influenced by gas-liquid mass transfer and/or the microbial activity depending on VOC properties such as solubility, diffusivity, bioavailability, and toxicity. Since the usual processes for VOCs removal involve water as a VOC absorbent, it is necessary to improve the removal efficiency of hydrophobic VOCs. In addition, VOC removal processes do not appear to show consistently satisfactory performance due to transient high-strength VOC loading in practical fields. To increase the gas-liquid mass transfer of hydrophobic VOCs and to prevent the functional deterioration due to transient high loading, the use of nonaqueous phase VOC absorbents is a promising strategy. This review offers a critical overview of the types, properties, and the applications of the VOC absorbents, including liquid organic solvents, ionic liquids, and solid polymers. This paper also details the advantages by employing the VOC absorbents for the removal of hydrophobic VOCs in the integrated process, absorption and biodegradation coupling process. The challenges of and future perspectives on the development of efficient VOC removal processes using VOC absorbents are briefly discussed.
        6,600원
        328.
        2018.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was conducted in 2014 in the Gangjin area of Jeonnam province for the purpose of confirming the potential of Kenaf as an alternative feed crop of rice. The weather and soil conditions were favorable and there was no adverse effect on the growth of Kenaf. The amount of seeding was given at 10 kg, 15 kg and 20 kg. As the seeding volume increased, plant height and dry matter yield increased, and stem diameter and number of nodes decreased. The highest growth rate was observed between 75 and 90 days from the date of planting(p<0.05). As the growth progressed, stem rate increased and leaf rate decreased(p<0.05). Increased amount of seeding and growth resulted in decreased CP and TDN and increased ADF and NDF, which resulted in the decreased economic value of Kenaf as a feed crop. The result of increasing the use of organic fertilizer to 20 kg and 30 kg was similar to increasing the amount of seeding. As organic fertilizer usage increased, dry matter yield and growth rate improved(p<0.05).
        4,000원
        329.
        2018.06 구독 인증기관 무료, 개인회원 유료
        대형저서동물에서 우점하고 있는 갯지렁이류는 퇴적층의 유기물 섭취를 통하여 저질환경개선 에 중요한 역할을 한다. 본 연구에서는 최근 양식기술이 개발된 바위털갯지렁이를 이용하여 갯 벌 퇴적층의 유기물 제거효과를 검토하였다. 이를 위하여 입자특성이 다른 세종류의 저질환경 (S1: 강사질, S2: 해사질, S3: 니사질)에서 해수 및 퇴적층의 TOC를 측정하였다. 바위털갯지렁이 는 세종류의 입자특성에서 모두 유기물 제거효과를 나타내었으며, 입자가 클수록 제거율이 높 았다. 유기물 정화능력을 정량적으로 평가한 결과 바위털갯지렁이는 각 저질별로 강사질에서 3.9856 ppm g-1d-1, 해사질에서 2.8021 ppm g-1d-1, 그리고 니사질에서 28.1142 ppm g-1d-1의 제거능력을 나타내었다. 본 연구결과는 바위털갯지렁이가 다양한 저질에서 유기물 제거에 기 여하고 있음을 보여 주었다.
        4,000원
        330.
        2018.05 구독 인증기관·개인회원 무료
        Two different emitting compounds, 1-[1,1;3,1]Terphenyl-5-yl-6-(10-[1,1;3,1]terphenyl-5-ylanthracen-9-yl)-pyrene (TP-AP-TP) and Poly-phenylene vinylene derivative (PDY 132) were used to white OLED device. By incorporating adjacent blue and yellow emitting layers in a multi-layered structure, highly efficient white emission has been attained. The device was fabricated with a hybrid configuration structure: ITO/PEDOT (40 nm)/PDY-132 (8∼50 nm)/NPB (10 nm)/TP-AP-TP (30 nm)/Alq3 (20 nm)/LiF (1 nm)/Al (200 nm). After fixing TP-AP-TP thickness of 30 nm by evaporation, PDY-132 thickness varied with 8, 15, 35, and 50 nm by spin coating in device. The luminance efficiency of the white devices at 10 mA/cm2 were 2.93 cd/A∼6.55 cd/A. One of white devices showed 6.55 cd/A and white color of (0.290, 0.331).
        331.
        2018.05 구독 인증기관·개인회원 무료
        4-Methyl-7-(10-phenyl-anthracen-9-yl)-chromen-2-one (PhAC), 4-Methyl-7-(10-naphthalen-1-yl-anthracen-9-yl)-chromen-2-one (1-NAC), 4-Methyl-7-(10-naphthalen-2-yl-anthracen-9-yl)-chromen-2-one (2-NAC), and 7-Anthracen-9-yl-4-methyl-chromen-2-one (AC) were synthesized through Suzuki aryl-aryl coupling reaction. Four compounds were used as emitting layer (EMLs) in non-doped OLEDs with the following structures: ITO/2-TNATA (60 nm)/NPB (15 nm)/EMLs (35 nm)/Alq3 (20 nm)/LiF (1 nm)/Al (200 nm). Non-doped devices showed luminescence efficiency of 2.14, 2.07, 1.52, and 1.12 cd/A at a current density of 10 mA/cm2.
        332.
        2018.05 구독 인증기관·개인회원 무료
        New three emitting compounds, AK-1, AK-2 and AK-3 including diazocine moiety were synthesized through Suzuki-coupling reaction. Physical properties such as optical, electroluminescent properties were investigated. UV-visible spectrum of AK-1, AK-2 and AK-3 in film state showed maximum 392, 393 and 401 nm. PL spectrum of AK-1, AK-2 and AK-3 showed maximum emission wavelength of 472, 473 and 435 nm. Three compounds were used as EML in OLED device: ITO/2-TNATA (60 nm)/NPB (15 nm)/EML (35 nm)/Alq3 (20 nm)/LiF (1 nm)/Al (200 nm). AK-3 OLED device showed C.I.E value of (0.18, 0.26) and luminance efficiency of 0.51 cd/A at 10 mA/cm2. New derivatives including diazocine moiety were introduced as OLED emitting material and the EL efficiency was increased by the proper combination of core and side group.
        333.
        2018.05 구독 인증기관·개인회원 무료
        4-methyl-7-(10-(pyren-1-yl)anthracen-9-yl)-2H-chromen-2-one (PAC), 7,7’-(anthracene-9,10-diyl)bis(4- methyl-2H-chromen-2-one) (CAC), 7-Anthracen-9-yl-4-methyl-chromen-2-one(AC), and 7-(naphthalen-1-yl)-2Hchromen-2-one (NC) were synthesized through Suzuki aryl-aryl coupling reaction. Optical and electroluminescence (EL) properties were evaluated by UV-visible absorption, photoluminescence (PL) spectra, and EL devices. Synthesized compounds were used as an emitting layer (EML) in non-doped device with the following structures: ITO/2-TNATA (60 nm)/NPB (15 nm)/synthesized compounds (35 nm)/Alq3 (20 nm)/LiF (1 nm)/Al (200 nm). Non-doped devices showed luminance efficiency (L.E.) of 1.38, 1.03, 1.12, and 0.39 cd/A at a current density of 10 mA/cm2.
        334.
        2018.05 구독 인증기관·개인회원 무료
        7-(4-([1,1-biphenyl]-4-yl(9,9-dimethyl-9H-fluoren-2-yl)amino)phenyl)-4-methyl-2H-chromen-2-one (BPFA-C) including coumarin moiety was synthesized through Suzuki aryl-aryl coupling reaction. Optical and electrical properties were examined by UV-visible absorption spectra, PL spectra, and AC-2. UV-visible spectrum of BPFA-C in a film state showed maximum absorption wavelength of 367 nm. PL spectrum of BPFA-C show maximum emission wavelength of 511 nm. BPFA-C showed highly efficient luminescence property. EL spectrum of BPFA-C exhibited a maximum value of 504 nm and BPFA-C device provided luminescence efficiency of 4.59 cd/A, power efficiency of 3.17 lm/W, and CIE (x,y) of (0.25, 0.53) at a current density of 10 mA/cm².
        335.
        2018.05 구독 인증기관·개인회원 무료
        Current petrochemical product mainly comes from light olefin, such as ethylene and propylene. these olefins can be obtained as mixture form of olefin/paraffin, which is co-product of naphtha cracking process. However, the mixture of light olefin and paraffin is considerably difficult to separate because they have similar physicochemical properties such as density, boiling point, and molecular weight. Cryogenic distillation is currently utilized, but still suffered from high operating cost. Membrane separation with polyimide-based material is a promising alternative due to its lower energy cost and modular operation. Here, we synthesized composite membrane with metal-organic framework (MOF) based on polyimide exhibiting high permeability and selectivity in propylene/propane separation, as well as simple preparation and high stability.
        336.
        2018.05 구독 인증기관·개인회원 무료
        지표수 성상을 재현한 용액을 가압식 한외여과 시스템을 통하여 100 L/m²/h 정속 조건에서 전량 여과하였다. 공극 크기 0.05 μm의 한외여과 중공사막으로 구성된 가압식 모듈을 통해 휴민산(HA) 10 mg/L 용액과 알긴산 나트륨(SA) 10mg/L 용액, 그리고 이 두 용액에 실리카(SiO2) 입자 50 mg/L이 포함된 총 4가지 용액을 여과하였다. 여과 공정은 30분 여과 후 30초 역세와 30초 정세의 주기적 물리 세정과 병행하여 수행되었다. 실험 결과, HA와 SA 용액에 SiO2 입자가 존재하는 경우 파울링 속도는 다소 감소하였으며 특히 SA 여과에서 SiO2 입자 위에 형성된 SA 케이크층이 세정에 의해 SiO2 입자와 함께 탈착되어 물리세정에 의한 분리막 성능 회복이 크게 증가하는 것으로 나타났다.
        337.
        2018.05 구독 인증기관·개인회원 무료
        MOF는 높은 표면적, 균일한 공극, 크기를 가지는 새로운 클래스의 porous material 이다. MOF는 금속과 organic linker가 coordination 결합에 의해 연결되어 있고, 온도에 대한 강한 안정성을 나타내고, 높은 표면적 때문에 촉매, 분리, 개스저장 등 다양한 분야에 적용될 수 있는 잠재력이 풍부하다. MOF는 zeolite보다 높은 표면적을 가지고 작용기를 organic linker에 따라 쉽게 바꿀 수 있는 장점 때문에 최근에 많은 관심을 받게 되었다. 다양한 MOF가 합성되었고 CO2/N2 선택도, 흡착량, 수분과 산성가스에 대한 안정성이 분석되었다. 최종적으로 선택된 MOF는 폴리머와 결합하여 하이브리드 멤브레인을 만드는 데에 사용되었다.
        338.
        2018.05 구독 인증기관·개인회원 무료
        유기용매 나노여과(OSN, organic solvent nanofiltration) 분리막은 폴리이마이드(PI)나 폴리벤질이미디아졸(PBI)과 같은 특수 고분자의 개발, 상업화가 이루어지고 강한 유기용매에 견딜 수 있도록 가교를 통해 분리막의 내구성이 급격하게 향상되면서 저분자량의 합성, 정제 및 농축을 필요로하는 의약, 바이오, 식품산업에 획기적이고 효율적인 분리막 공정으로 주목 받고 있다. 하지만 여전히 고가의 고분자, 가교를 위한 복잡한 프로세스, 다량의 강한 용매 폐수 발생등 상업화를 이루는데 여러 가지 문제점들이 산재하고 있다. 본 연구는 기존 제막방식에서 벗어나 무독성의 용제를 사용하여 단일공정으로 유기용매 나노여과 분리막을 제막하고 그 특성을 연구하였다.