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        검색결과 4,677

        1361.
        2016.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        올레핀/파라핀 혼합 기체의 분리를 위한 올레핀 촉진 수송 분리막의 제조를 위해 amide 작용기를 가지며 glassy한 특성을 보이는 polyvinylpyrrolidone (PVP) 고분자를 분리막의 matrix로서 사용하였다. 분리막의 기체 투과 실험은 propylene 과 propane 50 : 50의 부피비로 혼합된 기체를 사용하였고, bubble meter와 gas chromatography를 사용해 투과도와 선택도를 측정하였다. 또한 SEM image와 FT-IR을 통해 막의 특성을 조사하였다. 100시간의 장시간 성능 측정 결과 선택도는 약 15, 투과도는 약 1.3 GPU 이상을 각각 유지하였다. 기존의 poly(2-ethyl-2-oxazoline) (POZ)/AgBF4/Al(NO3)3 분리막과 비교함으 로써, 고분자 matrix로서의 PVP 특성을 확인하였다.
        4,000원
        1362.
        2016.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        폴리카프로락톤(PCL)에 NaCl을 혼합한 용액을 블레이드법에 의하여 막형태로 제조한 후 NaCl을 추출하는 염출 법을 이용하여 조직공학적으로 사용할 3차원 다공망을 갖는 멤브레인 형태의 지지체를 제조하였다. 본 연구에서는 성형된 멤 브레인의 건조조건과, NaCl 입자의 크기, NaCl의 혼합량을 각각 다르게 하여 제조하였다. 별도로 제작한 고분자용액 공급장 치를 이용하여 PCL/클로로포름(CHCl3) 용액에 NaCl 입자가 균일하게 혼합된 용액을 유리판에 분주하여 필름 어플리케이터 를 사용하여 블레이드법에 의한 멤브레인을 제조하였다. 멤브레인 지지체에는 NaCl 입자에 의한 거대기공과 거대기공을 이 루는 구조벽에서는 CHCl3의 증발에 의한 미세기공이 함께 복합적으로 상호 연결되어 형성되었다.
        4,000원
        1363.
        2016.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The microstructural properties and electrical characteristics of sputtering films deposited with a Cu-Ga target are analyzed. The Cu-Ga target is prepared using the cold spray process and shows generally uniform composition distributions, as suggested by secondary ion mass spectrometer (SIMS) data. Characteristics of the sputtered Cu-Ga films are investigated at three positions (top, center and bottom) of the Cu-Ga target by X-ray diffraction (XRD), SIMS, 4-point probe and transmission electron microscopy (TEM) analysis methods. The results show that the Cu-Ga films are composed of hexagonal and unknown phases, and they have similar distributions of composition and resistivity at the top, center, and bottom regions of the Cu-Ga target. It demonstrates that these films have uniform properties regardless of the position on the Cu-Ga target. In conclusion, the cold spray process is expected to be a useful method for preparing sputter targets.
        4,000원
        1364.
        2016.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Niobium is one of the most important and rarest metals, and is used in the electronic and energy industries. However, it’s extremely high melting point and oxygen affinity limits the manufacture of Nb coating materials. Here, a Nb coating material is manufactured using a kinetic spray process followed by hot isotactic pressing to improve its properties. OM (optical microscope), XRD (X-ray diffraction), SEM (scanning electron microscopy), and Vickers hardness and EPMA (electron probe micro analyzer) tests are employed to investigate the macroscopic properties of the manufactured Nb materials. The powder used to manufacture the material has angular-shaped particles with an average particle size of 23.8 μm. The porosity and hardness of the manufactured Nb material are 0.18% and 221 Hv, respectively. Additional HIP is applied to the manufactured Nb material for 4 h under an Ar atmosphere after which the porosity decreases to 0.08% and the hardness increases to 253 Hv. Phase analysis after the HIP shows the presence of only pure Nb. The study also discusses the possibility of using the manufactured Nb material as a sputtering target.
        4,000원
        1365.
        2016.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was performed to develop and evaluate cookies prepared with various amounts (0 g, 12.5 g, 25 g and 37.5 g) of mealworm powder to serve as not only sports snacks but also for the general population as a new protein source. In the chromaticity of mealworm cookies, lightness and yellowness decreased whereas redness increased with more mealworm powder. The hardness of the mealworm cookies increased as more mealworm powder was added. In sensory evaluation, higher preference was shown with the measure of color, taste, and overall preference for mealworm cookies prepared with 50% mealworm powder (MP2). For the general composition of MP2, the moisture, carbohydrate, crude protein, crude fat and crude ash were higher compared with the control cookie. For the mineral contents of MP2, the contents of Ca (33.44 mg/100 g), P (225.13 mg/100 g), Mg (82.21 mg/100 g), Na (246.22 mg/100 g), and K (503.49 mg/100 g) were higher compared with the control cookie. The essential amino acids (valine, isoleucine, leucine, methionine, threonine, phenylalanine, and histidine) in MP2 were also higher compared with the control cookie. It was concluded that MP2 can be used as a new protein source for not only the maintenance of muscle but also for the prevention of muscle loss in old people.
        4,000원
        1366.
        2016.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A bulk-type Ta material is fabricated using the kinetic spray process and its microstructure and physical properties are investigated. Ta powder with an angular size in the range 9-37 μm (purity 99.95%) is sprayed on a Cu plate to form a coating layer. As a result, ~7 mm-sized bulk-type high-density material capable of being used as a sputter material is fabricated. In order to assess the physical properties of the thick coating layer at different locations, the coating material is observed at three different locations (surface, center, and interface). Furthermore, a vacuum heat treatment is applied to the coating material to reduce the variation of physical properties at different locations of the coating material and improve the density. OM, Vickers hardness test, SEM, XRD, and EBSD are implemented for analyzing the microstructure and physical properties. The fabricated Ta coating material produces porosity of 0.11~0.12%, hardness of 311~327 Hv, and minor variations at different locations. In addition, a decrease in the porosity and hardness is observed at different locations upon heat treatment.
        4,000원
        1367.
        2016.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Cu-Mn compacts are fabricated by the pulsed current activated sintering method (PCAS) for sputtering target application. For fabricating the compacts, optimized sintering conditions such as the temperature, pulse ratio, pressure, and heating rate are controlled during the sintering process. The final sintering temperature and heating rate required to fabricate the target materials having high density are 700oC and 80oC/min, respectively. The heating directly progresses up to 700oC with a 3 min holding time. The sputtering target materials having high relative density of 100% are fabricated by employing a uniaxial pressure of 60 MPa and a sintering temperature of 700oC without any significant change in the grain size. Also, the shrinkage displacement of the Cu-Mn target materials considerably increases with an increase in the pressure at sintering temperatures up to 700oC.
        4,000원
        1368.
        2015.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        In this study, the properties of Ag-coated TiO2 nanoparticles were observed, while varying the molar ratio of water and Ag+ for the surfactant and TiO2. According to the XRD results, each nanoparticle showed a distinctive diffraction pattern. The intensity of the respective peaks and the sizes of the nanoparticles increased in the order of AT1(R1 = 5)(33.3 nm), AT2 (R1 = 10)(38.1 nm), AT3(R1 = 20)(45.7 nm), AT4(R1 = 40)(48.6 nm) as well as AT5(R2 = 0.2, R3 = 0.5)(41.4 nm), AT6(R2 = 0.3, R3 = 1)(45.1 nm), AT7(R2 = 0.5, R3 = 1.5)(49.3 nm), AT8(R2 = 0.7, R3 = 2)(57.2 nm), which values were consistent with the results of the UV-Vis. spectrum. The surface resistance of the conductive pastes fabricated using the prepared Ag-coated TiO2 nanoparticles exhibited a range 7.0~9.0(274~328 μΩ/cm2) times that of pure silver paste(ATP)(52 μΩ/cm2).
        4,000원
        1369.
        2015.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was carried out for characterization of MIO synthesized in our laboratory by co-precipitation method and applied isotherm and kinetic models for adsorption properties. XRD analysis were conducted to find crystal structure of synthesized MIO. Further SEM and XPS analysis was performed before and after phosphate adsorption, and BET analysis for surface characterization. Phosphate stock solution was prepared by KH2PO4 for characterization of phosphate adsorption, and batch experiment was conducted using 50 ml conical tube. Langmuir and Freundlich models were applied based on adsorption equilibrium test of MIO by initial phosphate solution. Pseudo first order and pseudo second order models were applied for interpretation of kinetic model by temperature. Surface area and pore size of MIO were found 89.6 m2/g and 16 nm respectively. And, the determination coefficient (R2) value of Langmuir model was 0.9779, which was comparatively higher than that of Freundlich isotherm model 0.9340.
        4,000원
        1370.
        2015.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study investigates ventilation and processing methods for industrial facilities by analyzing the distribution chart and concentration of fine particles generated. Analyses of fine particles were conducted in crushing rooms, sorting room, Primary manufacturing room and packing room, where the concentration of 0.3~10.0 μm particles were measured for 10 minutes during processing of herb medicines. The result revealed that particles with sizes greater than or equal to PM2.685 took up most of the space, and the concentration of fine particles (PM10) was 1,672.24 μg/m3 in 1th crushing room, 3,144.7 μg/m3 in crushing 2nd room, 262.45 μg/m3 in sorting room, prior to processing (2,302.3 μg/m3 for Aralia continentails and 5,564.9 μg/m3 for Poria cocos), 4,656.5 μg/m3 in Primary manufacturing room, and 20,213.3 μg/m3 in packing room. The concentration of fine particles generated during manufacture of herb medicines was, in comparison to the standard of 150 μg/m3 established in the Indoor Air Quality Control Act, 1.7 to 135 times higher. High concentrations of fine particles were found in all rooms, except for packing, even with partial ventilation. Also, it can be inferred that adequate deodorization system may be required in order to control unpleasant herb odors. Through this study, it is recommended that the use of scrubbers and concealment may facilitate control of fine particles containment.
        4,000원
        1371.
        2015.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Many enterprises have been adopting management systems good enough for them and operating the schemes to have competitive edge better than their competitor. One of the finest systems that most companies have been selecting is ISO 14001. ISO 14001, environment management system, is widely known as advancing internal efficiency and productivity in the various industries. As a result, the number of companies that have adopted ISO 14001’s certification have been increasing continuously year by year since ISO 14000 standard was called in 1994s from ISO 18000 standard that originally used. The purpose of this study is to present that ISO 14001’s requirement execution influences on management performance in the small manufacturer. In order to carry out this research, we obtained 96 survey sheets and inspected ten assumptions based on the reliability, validity of the questionnaires. The results of regression analysis are summarized as follows; First, the three factors of ISO 14001 requirement, plan, implementation and operation and management consideration, have an important effect on the operational performance. Second, the three elements of ISO 14001 requirement, environment policy, implementation and operation and management consideration, affect to the financial performance significantly. Based on the results, it is sure that the companies that execute the factors of implementation and operation and management policy have a good performance to achieve operational and financial performance so that it is important to clarify the member’s role, authority and follow the procedure by a company’s process. Also, the truth shows CEO’s continuous will and periodical review of ISO 14001 influence on management performance as well.
        4,000원
        1372.
        2015.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        ISO 9001, quality management system, is widely known as advancing internal efficiency and productivity in various industry. As a result, the number of companies that have adopted ISO 9001’s certification have been increasing continuously year by year since ISO 9000’ family standard was published in 1987s. This fact shows that a lot of businesses are trying to get the accreditation for improving the competitiveness of quality. The purpose of this study is to present that ISO 9001’s certification motives affect to the requirement’s implementation and show that the execution of requirements influences on management performance in the small manufacturer. In order to carry out this research, we obtained 96 survey sheets and inspected twenty assumptions based on the reliability, validity of the questionnaires. The results of regression analysis are summarized as follows; First, the factors of certification motive influence on the requirement’s implementation except resources management. Second, the two elements of ISO 9001 requirement, resources management and product realization, have an important effect on the operational performance and financial performance considerably in the companies that choose the internal motive. Finally, the two requisites of ISO 9001 requirement, resources management and measurement, analysis and improvement, affect to the operational performance and financial performance significantly in the businesses that select the external motive. Based on the results, the companies that choose the internal motive have a good performance to execute the ISO 9001 requirements. Also, to implement the requirements of ISO 9001 is helpful for the companies to produce the operational and financial performance.
        4,000원
        1373.
        2015.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study attempted to find an efficient method for the preparation of high-purity galactooligosaccharides (HP-GOS) using β-galactosidase and yeast fermentation. GOS prepared using Lactozym 3000L showed the greatest enhancement in total GOS of the six β-galatosidases tested. GOS alone achieved 51% conversion of initial lactose. GOS production was enhanced by fermentation with commercial yeast (Saccharomyces cerevisiae); its concentration reached 71% after 36h fermentation with 8% yeast. Component sugar analysis with HPLC indicated that HP-GOS fermented with S. cerevisiae showed significantly increased levels of 4’/6’-galactosyllactose and total GOS as well as a significantly decreased glucose level. HP-GOS facilitated the growth of Lactobacillus sp. (L. acidophilus and L. casei) and Bifidobacterium sp. (B. longum and B. bifidum). In sum, high-purity GOS has been successfully produced through both an enzymatic process and yeast fermentation. GOS encourages the growth of bacteria such as Lactobacillus and Bifidobacterium that may be beneficial to human gastrointestinal health.
        4,000원
        1374.
        2015.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 이산화탄소와 석탄을 사용하여 합성가스 CO를 생산하는 실험을 수행하였다. CO 합성특성은 KOH 촉매를 사용한 화학적 활성화 방법에 의해 조사되었으며, 제조공정은 CO2 전환 반응에서 석탄과 활성화 촉매 비율, 가스 유량과 반응온도 등과 같은 실험변수들을 분석함으로서 최적화 되었다. KOH 촉매를 사용하지 않은 경우, 반응온도 950℃와 CO2 유량 300 cc/min에서 65% CO2 전 환율을 얻었으며, 반면에 촉매를 사용한 경우 같은 반응조건에서 98.1%의 전환율을 얻었다. 석탄의 활 성화촉매 반응물의 비(석탄 : KOH = 4 : 1)가 다른 반응물 비에 대해 더 좋은 CO2 전환율과 CO 선 택도 보여줌을 알 수 있었다.
        4,000원
        1375.
        2015.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 웰빙(well-being)으로 각광받고 있는 천연물 관련 연구에 무화과 추출물의 활용 가능 성을 확인하고자 다음의 연구를 수행하였다. 무화과를 세척 건조하여 알코올추출 방법으로 추출한 후, Column chromatography, G-Mass, IR, 1H-nmr 방법에 의하여 무화과 추출물의 이화학적 성질을 분석하 였으며, 무화과 추출물을 두피 제품에 적용하기 위하여 항균, 항진균에 대한 항균성을 조사하였다. 무화과 추출물의 이화학적 분석은 열매와 잎으로 나누어 분석하였으며, 두 부분 모두 비듬과 피부병 치료 효능을 가진 항균 및 항진균 효능이 있음을 알 수 있었다. 또한 무화과 추출물에 대한 항균성은 액체배지 희석법에 의해 분석하였다. 그리고 소비자의 구매 욕구를 충족시키고, 무화과의 산업화 타당성을 검토하기 위하여 무화과 추출물 함유 수제 투명 및 고형 비누를 제조하여 타당성을 검토하였다.
        4,900원
        1376.
        2015.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 높은 이산화탄소 분리성능을 가지는 폴리이미드의 제조를 위해 2,2-bis(3,4-carboxylphenyl) hexafluoropropane과 두종류의 아민인 2,3,5,6-tetramethyl-1,4-phenylenediamine, Poly(ethylene glycol) bis(3-aminopropyl) terminated을 이용하여 합성을 진행하였다. 합성된 고분자를 비용매 상전이법으로 비대칭 분리막을 제조하기 위하여 고분자의 용 해도 지수 추정 값과 비용매 상전이 계수 측정을 통해 용매를 선정하였고, 고분자 용액 점도 측정을 통해 분리막 제조를 위 한 도프용액 중의 고분자의 함량을 결정하여 질산리튬을 첨가제로 사용하여 최종적으로 분리막을 제조하였다. 제조된 평판형 비대칭 분리막은 전자주사현미경(SEM)을 통해 질산리튬과 휘발성 용매 함량에 변화에 따른 모폴로지의 변화를 확인하였으 며, 이의 변화에 따른 기체 투과도 변화를 확인하였다. 분리막 제조를 위한 도프용액 중의 휘발성 용매 함량이 작을수록 선택 도 변화가 없으면서 이산화탄소 투과도가 증가하는 것을 확인하였다.
        4,200원
        1377.
        2015.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        폴리설폰막 위에 친수성 고분자를 Layer-by-Layer법으로 코팅하여 복합막을 제조하였다. FE-SEM 분석을 통하여 복합막 표면과 기공 내 코팅층을 확인하였다. 또한 100 ppm NaCl 용액에 대한 복합막의 투과성능 평가를 실시하였다. 복합 막 제조를 위한 코팅 고분자는 PVSA, PEI, PAA, PSSA, PSSA_MA를 사용하였다. 폴리설폰막 표면에 8,000 ppm PAA (이 온세기 0.35) 수용액을 3분 동안 코팅한 뒤 10,000 ppm PEI 수용액을 4분 동안 코팅하였다. 그 결과 PAA-PEI 복합막의 투과 도는 101 LMH, 제거율은 66.7%로 가장 좋은 투과성능을 나타내었다. PAA-PEI 복합막의 투과성능은 도레이케미칼의 NE 4040-70 (투과도 = 30 LMH, 염 배제율 = 40~70%) 제품과 유사한 성능을 보여주는 우수한 투과 특성을 나타내었다.
        4,000원
        1378.
        2015.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        태양광 발전시스템은 태양복사에너지를 반도체의 광전효과를 이용하여 전기에너지로 직접 전환시키는 에너지변환 시스템이다. 태양전지의 내구성과 에너지변환율에 영향을 미치는 핵심소재로는 다층형 필름구조를 갖는 백시트를 들 수 있다. 대표적인 상용 백시트는 고내구성 poly(vinyl fluoride) (PVF) 필름이 중심축에 위치하고 가격저감을 위해 도입된 poly(ethylene terephthalate) (PET) 필름이 그 양쪽에 접합된 삼층구조로 구성된다. 하지만, PVF 필름의 높은 가격은 저렴한 고내구성 백시트 를 요구하는 시장상황을 반영하기 어렵게 한다. 이를 위한 해결책으로는 PVF 필름을 결정성 PET 필름으로 대체한 탄화수소계 백시트가 될 수 있다. 하지만, PET 필름의 본질적인 가수분해에 대한 취약성으로 인해, 추가적인 수분에 대한 배리어성 부여 는 필수적이다. 이를 위해 본 연구에서는 소수성 실리카 나노입자 분산기술을 활용한 수분차단성 폴리우레탄 접착제를 개발 코자 하였다. 개발된 접착제는 내부에 위치한 PET 필름으로의 수분침투를 약화시켜, 가수분해속도를 지연시킬 것이라 기대 되었다. 본 개념의 효용성을 확인하기 위해, 표준화된 온습도조건에 노출된 이후의 일반접착제와 수분차단성 접착제가 도입 된 백시트의 기계적 강도 및 시간당 태양전지성능 변화가 비교평가되었다.
        4,000원
        1379.
        2015.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        상업적으로 이용되는 폴리스티렌계 이온교환막은 제조 공정이 쉽고 간단하지만 막이 가지는 취성 때문에 내구성이 약하다는 단점을 가지고 있다. 이를 보완하기 위하여 친수성 그룹인 poly(ethylene glycol)을 곁사슬로 가지고 있는 poly(ethylene glycol)methyl ether methacrylate를 공중합시켜 음이온 교환막을 합성하였다. 지지체로는 내화학성 및 기계적 강도가 우수한 다 공성 PE 지지체를 사용하였고, 여기에 다양한 조성의 vinylbenzyl chloride, styrene, poly(ethylene glycol)methyl ether methacrylate, divinylbenzene, benzoyl peroxide를 녹인 단량체 용액을 지지체 기공에 채운 뒤 열중합 가교시켜 trimethylamine을 이 용하여 음이온 교환기를 도입해 세공충전 음이온 교환막을 합성하였다. 또한 poly(ethylene glycol)methyl ether methacrylate의 곁사슬 길이와 각 단량체가 차지하는 비율의 변화가 음이온 교환막의 전기화학적 특성에 미치는 영향을 알아보았다.
        4,000원
        1380.
        2015.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Porous thick film of alumina which is fabricated by freeze tape casting using a camphene-camphor-acrylate vehicle. Alumina slurry is mixed above the melting point of the camphene-camphor solvent. Upon cooling, the camphene- camphor crystallizes from the solution as particle-free dendrites, with the Al2O3 powder and acrylate liquid in the interdendritic spaces. Subsequently, the acrylate liquid is solidified by photopolymerization to offer mechanical properties for handling. The microstructure of the porous alumina film is characterized for systems with different cooling rate around the melting temperature of camphor-camphene. The structure of the dendritic porosity is compared as a function of ratio of camphene-camphor solvent and acrylate content, and Al2O3 powder volume fraction in acrylate in terms of the dendrite arm width.
        4,000원