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        검색결과 4,677

        301.
        2023.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The global demand for raw lithium materials is rapidly increasing, accompanied by the demand for lithiumion batteries for next-generation mobility. The batch-type method, which selectively separates and concentrates lithium from seawater rich in reserves, could be an alternative to mining, which is limited owing to low extraction rates. Therefore, research on selectively separating and concentrating lithium using an electrodialysis technique, which is reported to have a recovery rate 100 times faster than the conventional methods, is actively being conducted. In this study, a lithium ion selective membrane is prepared using lithium lanthanum titanate, an oxide-based solid electrolyte material, to extract lithium from seawater, and a large-area membrane manufacturing process is conducted to extract a large amount of lithium per unit time. Through the developed manufacturing process, a large-area membrane with a diameter of approximately 20 mm and relative density of 96% or more is manufactured. The lithium extraction behavior from seawater is predicted by measuring the ionic conductivity of the membrane through electrochemical analysis.
        4,000원
        302.
        2023.02 구독 인증기관 무료, 개인회원 유료
        3,000원
        303.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A turbo engine is used to improve engine volumetric efficiency by using the energy of exhaust gas with a device such as a turbocharger. Recently, it has been attracting attention as a solution for responding to environmental issues such as exhaust gas regulation, and its use is being expanded to gasoline and CNG engines as well as diesel engines. However, as electric and hydrogen vehicles enter the automotive market more rapidly, traditional turbo engines also confront many challenges. In this paper, to examine the current status and prospects of the turbo engine, we analyze the related patents in the turbo engine field applied to patent offices in seven major countries, including Korea, USA, China, Japan, Germany, France, and the European Union Patent Office, and analyze the patent application trend. Using ‘the pie’ system of Korea Institute of Science and Technology Information (KISTI), family patents were refined, patent application trends were diagnosed, and the technology and market competitiveness of major applicants were compared and analyzed. Even within the turbo engine market, where traditional automakers and turbocharger manufacturer participate, it was possible to examine the dynamic changes in the market through the analysis of technology and market competitiveness. The main companies leading the technology and market aspects and the companies specialized in the technology and market aspects were observed.
        4,000원
        304.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Recently, as interest in safe food and ingredient content has increased, the demand for highly concentrated health functional food that can be manufactured at home is increasing. Accordingly, in this study, we developed a galenic maker that can increase the extraction efficiency of herbal medicine(ginseng) ingredients and shorten the manufacturing time. After verifying the safety of the designed components through structural analysis and thermal flow analysis, the dimensions and shape of the galenic maker were determined. A prototype was produced based on the design process and the performance of the product was verified through extraction efficiency and ingredient analysis.
        4,000원
        305.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        There is a considerable amount of research on metal material product worker’s hearing loss caused by noise that comes from manufacturing process. A further investigation that characterizes the sound that comes from manufacturing process of metal material products. however. To do this, a noise management plan is needed. It should include a generated sound process from the main sources of disturbance at manufacturing process areas. And a soundproof measurement will identify the amount of noise reduction needed for a hearing-safe working environment. Finally, researchers in this study measured tests on the noise and the vibration process, and the noise caused by operations allowed for an investigation on the suitability of certain environmental conditions. Noise-related programs can be used to predict the noise distribution of the noise level characteristic. This can help identify and reduce the presence of sound interference through sound proofing measures.
        4,000원
        306.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Ion-beam irradiation(IB) on HfO2 surface induced high-performance liquidcrystal(LC) driving at a 1-V threshold with vertical alignment of liquid crystals(LC). The high-k materials Atomic layer deposition was used to obtain LC orientation on ultra thin and high-quality films of HfO2 layers. To analyze surface morphological transition of HfO2 which can act as physic alignment effect of LC, atomic force micro scopy images are employed with various IB intensities. The contact angle was measured to elucidate the mechanism of vertical alignment of LC on HfO2 with IB irradiation. Contact angle measurements show the surface energy changes via IB intensity increasing.
        4,000원
        307.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We investigate the austenite stability in nanocrystalline Fe-7%Mn-X%Mo (X = 0, 1, and 2) alloys fabricated by spark plasma sintering. Mo is known as a ferrite stabilizing element, whereas Mn is an austenite stabilizing element, and many studies have focused on the effect of Mn addition on austenite stability. Herein, the volume fraction of austenite in nanocrystalline Fe-7%Mn alloys with different Mo contents is measured using X-ray diffraction. Using a disk compressive test, austenite in Fe–Mn–Mo alloys is confirmed to transform into strain-induced martensite during plastic deformation by a disk d. The variation in austenite stability in response to the addition of Mo is quantitatively evaluated by comparing the k-parameters of the kinetic equation for the strain-induced martensite transformation.
        4,000원
        308.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The objective of this study is to assess the impact of spray drying conditions on medium-chain triglyceride (MCT) loading, solubility, and release of an MCT-loaded solid self-emulsifying system in a water-insoluble oily substance. MCT-loaded solid self-emulsifying systems are prepared by spray drying with SDS and calcium silicate. The effects of inlet temperature (60, 80, or 100oC) and feed solution composition (0, 10, 50, 90, or 100% ethanol) on physicochemical properties of MCT-loaded solid self-emulsifying systems are studied. The inlet temperature significantly affects the water solubility of MCT. Moreover, the feed solution composition significantly affects water solubility, release rate, and MCT loading. The MCT-loaded solid self-emulsifying system obtained at 60oC using 90% ethanol feed solution shows the best physicochemical properties among the synthesized products and exhibits better water solubility (4.43 ± 0.44 vs. 0 μg/mL) and release (94.4 ± 1.6 vs. 32.8 ± 7.4%, 60 min) than a commercial product. Furthermore, the MCT-loaded solid self-emulsifying system shows an excellent emulsion droplet size (approximately 230 nm).
        4,000원
        309.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        N-doped Na2Ti6O13@TiO2 (denoted as N-NTO@TiO2) composites are successfully synthesized using a simple two-step process: 1) ball-milling of TiO2 with Na2CO3 followed by heat treatment at 900oC; 2) mixing of the prepared Na2Ti6O13 with titanium isopropoxide and calcining with urea at 500oC. The prepared composites are characterized using XRD, SEM, TEM, FTIR, and BET. The N-NTO@TiO2 composites exhibit well-defined crystalline and anatase TiO2 with exposed {101} facets on the external surface. Moreover, dopant N atoms are uniformly distributed over a relatively large area in the lattice of the composites. Under visible light irradiation, ~51% of the aqueous methylene blue is photodegraded by N-NTO@TiO2 composites, which is higher than the values shown by other samples because of the coupling effects of the hybridization of NTO and TiO2, N-doping, and presence of anatase TiO2 with exposed {101} facets.
        4,000원
        310.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Lithium lanthanum titanium oxide (LLTO) is a promising ceramic electrolyte because of its high ionic conductivity at room temperature, low electrical conductivity, and outstanding physical properties. Several routes for the synthesis of bulk LLTO are known, in particular, solid-state synthesis and sol-gel method. However, the extremely low ionic conductivity of LLTO at grain boundaries is one of the major problems for practical applications. To diminish the grain boundary effect, the structure of LLTO is tuned to nanoscale morphology with structures of different dimensionalities (0D spheres, and 1D tubes and wires); this strategy has great potential to enhance the ion conduction by intensifying Li diffusion and minimizing the grain boundary resistance. Therefore, in this work, 0D spherical LLTO is synthesized using ultrasonic spray pyrolysis (USP). The USP method primarily yields spherical particles from the droplets generated by ultrasonic waves passed through several heating zones. LLTO is synthesized using USP, and the effects of each precursor and their mechanisms as well as synthesis parameters are analyzed and discussed to optimize the synthesis. The phase structure of the obtained materials is analyzed using X-ray diffraction, and their morphology and particle size are analyzed using field-emission scanning electron microscopy.
        4,000원
        311.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Thermal protection systems (TPS) are a group of materials that are indispensable for protecting spacecraft from the aerodynamic heating occurring during entry into an atmosphere. Among candidate materials for TPS, ceramic insulation materials are usually considered for reusable TPS. In this study, ceramic insulation materials, such as alumina enhanced thermal barrier (AETB), are fabricated via typical ceramic processing from ceramic fiber and additives. Mixtures of silica and alumina fibers are used as raw materials, with the addition of B4C to bind fibers together. Reaction-cured glass is also added on top of AETB to induce water-proof functionality or high emissivity. Some issues, such as the elimination of clumps in the AETB, and processing difficulties in the production of reusable surface insulation are reported as well.
        4,000원
        312.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study aimed to develop an optimal processing method for the production of apple-mango jelly for domestic suppliers, by analyzing the quality attributes of the jelly. According to the central composite design, a total of 11 experimental points were designed including the content of apple-mango juice (X1), and the sugar content (X2). The responses were analyzed including the color values (CIE Lab and color difference), physicochemical properties (water activity, sweetness, pH, and total acidity), and textural properties (hardness and gel strength). Regression analysis was conducted, except for total acidity, and showed no significant difference for all the experimental points (p<0.05). Quadratic model was derived for all responses with an R square value ranging from 0.8590 to 0.9978. Based on regression model, the appropriate mixing ratio of apple-mango jelly was found to be 31.11% of apple mango juice and 14.65% of sugar. Through this study, the possibility for developing jelly product using apple-mango was confirmed, and it is expected that these findings will contribute to the improvement of the agricultural industry.
        4,000원
        313.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Starfish are creatures that destroy marine ecosystems due to their high reproductive rate and predatory nature. Instead of mass incineration, this study attempted to utilize them as functional adsorbents to control odorous organic compounds. This waste starfishbased adsorbent showed a high aldehyde capture efficiency of 91.1%. The maximum specific surface area of the prepared waste starfish adsorbent was 2.19m2/g, and the adsorption amount was 101.66mg/g. Therefore, it was confirmed that the waste starfish had the ability to perform well as an adsorbent.
        4,000원
        314.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Manufacturing process mining performs various data analyzes of performance on event logs that record production. That is, it analyzes the event log data accumulated in the information system and extracts useful information necessary for business execution. Process data analysis by process mining analyzes actual data extracted from manufacturing execution systems (MES) to enable accurate manufacturing process analysis. In order to continuously manage and improve manufacturing and manufacturing processes, there is a need to structure, monitor and analyze the processes, but there is a lack of suitable technology to use. The purpose of this research is to propose a manufacturing process analysis method using process mining and to establish a manufacturing process mining system by analyzing empirical data. In this research, the manufacturing process was analyzed by process mining technology using transaction data extracted from MES. A relationship model of the manufacturing process and equipment was derived, and various performance analyzes were performed on the derived process model from the viewpoint of work, equipment, and time. The results of this analysis are highly effective in shortening process lead times (bottleneck analysis, time analysis), improving productivity (throughput analysis), and reducing costs (equipment analysis).
        4,000원
        315.
        2022.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Tin-antimony sulfide nanocomposites were prepared via hydrothermal synthesis and a N2 reduction process for use as a negative electrode in a sodium ion battery. The electrochemical energy storage performance of the battery was analyzed according to the tin-antimony composition. The optimized sulfides exhibited superior charge/discharge capacity (770 mAh g-1 at a current density of 100 mA g-1) and stable lifespan characteristics (71.2 % after 200 cycles at a current density of 500 mA g-1). It exhibited a reversible characteristic, continuously participating in the charge-discharge process. The improved electrochemical energy storage performance and cycle stability was attributed to the small particle size, by controlling the composition of the tin-antimony sulfide. By optimizing the tin-antimony ratio during the synthesis process, it did not deviate from the solubility limit. Graphene oxide also acts to suppress volume expansion during reversible electrochemical reaction. Based on these results, tin-antimony sulfide is considered a promising anode material for a sodium ion battery used as a medium-to-large energy storage source.
        4,000원
        316.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 비가열 떡 제조업체 3곳을 대상으로 원 재료, 제조설비 및 계절별 제조공정에 대한 미생물 오염 도를 분석하였고, 여름철 불림 시간에 따른 미생물 오염 도 및 불림 수 온도 조절을 통한 미생물 저감 효과를 확 인하고자 하였다. 3업체의 원재료 일반세균수는 2.69-5.08 log CFU/g 범위로 검출되었으나 제조공정 중 불림공정에 서 미생물 오염도가 급격히 증가함을 확인하였다. 계절에 따른 제조공정별 미생물 오염도 분석결과, 여름철 불림공 정에서 일반세균 및 대장균군이 7.01 및 3.96 log CFU/g 로 다른 계절에 비해 유의적으로 높게 나타났고, 이후 공 정에서도 높은 오염도를 유지하여 냉동공정에서 일반세균 이 6.24 log CFU/g로 법적인 기준을 초과하여 검출되었다. 여름철 불림 초기 수온은 19.1oC에서 불림 12시간 후 26.8oC까지 상승하였고, 불림시간에(3, 6, 9, 12 h) 따른 제조공정별 미생물 오염도 분석결과, 불림시간이 길어질수 록 미생물 오염도가 유의적으로 높게 나타났고, 불림 9시 간 이후부터 냉동공정의 일반세균 수치가 냉동식품의 법 적인 기준을 초과하여 검출되었다. 여름철 불림 수의 온 도 상승을 억제하기 위하여 얼음팩을 이용하여 불림 수온 을 조절한 결과, 불림 12시간까지 20.1oC로 유지되어 조 절 전보다 약 7oC가량 낮게 나타났다. 이에 따른 제조공 정별 미생물 오염도 분석결과, 3업체의 불림 12시간 이후 냉동공정 일반세균 평균값이 4.42 log CFU/g로 조절 전보 다 1.77 log CFU/g 감소한 것으로 확인되었다. 이상의 결 과로 볼 때, 안전한 비가열 냉동떡 생산을 위해서는 업체 에 맞는 불림시간 및 불림 수 온도조절 등의 선행요건 관 리기준 설정이 필요하며, 이러한 선행요건 관리기준의 적 용으로 비가열 냉동떡 제조 HACCP system의 안전성이 확립될 수 있을 것으로 판단되었다.
        4,200원
        317.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        목적 : 반응성 청색광차단 염료를 하이드로겔 콘택트렌즈에 화학적으로 고정시켰고, 제조된 콘택트렌즈의 청색 광차단 기능의 분석 및 첨가된 염료를 정량하고자 한다. 방법 : Vinyl sulfone-기반의 반응성 염료인 Reactive Orange 16 Dye를 다량의 알콜 작용기를 함유하는 하 이드로겔 콘택트렌즈에 화학적으로 결합시켰다. 콘택트렌즈의 청색광차단 특성 및 염료의 정량은 UV-vis spectrophotometer를 이용하여 확인하였다. 결과 : 청색광차단기능의 Reactive Orange 16 Dye가 성공적으로 하이드로겔 콘택트렌즈에 결합되었다. UV-vis spectra 분석을 통해 염료를 함유한 콘택트렌즈들이 우수한 청색광차단 기능을 보임을 확인하였다. Beer-Lambert의 법칙을 이용하여, 콘택트렌즈에 첨가된 Reactive Orange 16 Dye를 정량하였으며, 반응 염료 의 농도 조절을 통해, 콘택트렌즈의 청색광차단율을 조절할 수 있었다. 결론 : 본 연구에서는 청색광차단 기능의 반응성 염료를 하이드로겔 콘택트렌즈에 화학적 결합을 통해 고정시 키고, 청색광차단 기능을 분석하였다. 화학적 반응에서 청색광차단 염료의 농도가 증가할수록, 380~500 nm 사 이의 청색광 파장 영역에서의 차단 세기와 첨가된 염료의 양이 같이 증가함을 확인하였다. 대량생산이 가능한 청 색광차단 콘택트렌즈의 개발은 기능성 안광학의료기기 개발에 큰 역할을 할 것으로 기대된다.
        4,000원
        318.
        2022.11 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        For the selective catalytic reduction of NOx with ammonia (NH3-SCR), a V2O5WO3/TiO2 (VW/nTi) catalyst was prepared using V2O5 and WO3 on a nanodispersed TiO2 (nTi) support by simple impregnation process. The nTi support was dispersed for 0~3 hrs under controlled bead-milling in ethanol. The average particle size (D50) of nTi was reduced from 582 nm to 93 nm depending on the milling time. The NOx activity of these catalysts with maximum temperature shift was influenced by the dispersion of the TiO2. For the V0.5W2/nTi-0h catalyst, prepared with 582 nm nTi-0h before milling, the decomposition temperature with over 94 % NOx conversion had a narrow temperature window, within the range of 365-391 °C. Similarly, the V0.5W2/nTi-2h catalyst, prepared with 107 nm nTi-2h bead-milled for 2hrs, showed a broad temperature window in the range of 358~450 °C. However, the V0.5W2/Ti catalyst (D50 = 2.4 μm, aqueous, without milling) was observed at 325-385 °C. Our results could pave the way for the production of effective NOx decomposition catalysts with a higher temperature range. This approach is also better at facilitating the dispersion on the support material. NH3-TPD, H2-TPR, FT-IR, and XPS were used to investigate the role of nTi in the DeNOx catalyst.
        4,300원
        319.
        2022.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, the authors investigated the quality characteristics of convenient rice porridge made from powder (PR) and half-rice (HR) sized freeze-dried cooked rice using Samgwang and Jinsumi rice. The hydration properties of the freeze-dried cooked rice and the color, viscosity, spreadability, and sensory evaluation of porridge were measured. PR showed significantly higher water-binding capacity, solubility, and swelling power than HR for both varieties (p<0.05). As a result of the quality characteristic of the porridge, PR showed significantly higher lightness, redness, yellowness, viscosity, and spreadability than HR (p<0.05). Acceptance testing showed that HR had significantly better results for all acceptance attributes than PR (p<0.05). Jinsumi HR showed better consumer acceptance for taste, texture, and overall acceptability than Samgwang HR (p<0.05). Intensity evaluations of sensory properties revealed that the Samgwang PR was more spreadable but was less chewy than Samgwang HR. Furthermore, Jinsumi HR had higher transparency, greater spreadability, and a better cooked-rice odor and savory taste than Samgwang HR (p<0.05). These results confirm that convenient porridges can be produced using freezedried cooked rice.
        4,200원