Characteristics of plasma nitriding and nitrocarburizing for steam treated sintered steels were studied. Fe-0.8%C powder containing Ni, Cu were sintered at 112 and steamed at 52. Temperature of plasma nitriding and nitrocarburizing was varied from 50 to . Gas mixture of nitriding was set at : =80:20 (vol.%), but was added 1~2 vol.% for nitrocarburizing. Steam treatment for sintered steels brought not only the formation of oxide layer but also decarburizing near the surface. Decrease in hardness near the surface resulted from the formation of ferrite due to decarburizing. Thus, the low hardness was recovered not with plasma nitriding but with plasma nitrocarburixing. Wear resistance properties of steamed specimens and ni-trocarburized specimens were better than those of nitrided specimens according to the pin-on-disk wear test. On the other hand, the fatigue life of steamed specimen was shorter than that of nitrocaiburized specimen.

솔잎의 향기성분을 용매분획과 수증기증류법으로 분석한 결과는 다음과 같다. 솔잎을 hexane, ethyl acetate 및 ethanol로 연속적으로 추출하였을 때, 29종의 향기성분이 분리, 확인되었고, 주요 성분은 hydrocarbon이었다. hexane 추출에 의한 솔잎의 주요 향기성분은 α-pinene, β-thujene, trans-caryophyllene, β-cubebene 순으로 높게 나타났다. 솔잎을 hexane으로 추출한 잔사에 ethyl acetate를 가하여 향기 성분을 분석하였을 경우 추출된 향기성분은 α-cubebene, 3,6,9,12,15-petaoxanonadecan-1-ol, camphene, 순으로 높았고, 솔잎을 hexane 및 ethyl cetate로 추출한 잔사에 ethanol을 가하여 분석한 경우는 β-D4-tetrahydropyran, γ-cadinene, 3-ethyl-1,4-hexadiene, α-cubebene등이 주성분이었다. 솔잎을 수증기 증류하여 향기성분을 분석한 결과 44종의 성분이 분리, 확인되었고, hydrocarbon류가 주성분이었다. β-cubebene, trans-caryophyllene, 2-hexenal, T-muurolol, δ-cadinene 순이었다. 수증기 증류법에 의한 방법으로 추출 하였을 때 용매분획 추출시 보다 더 많은 성분이 검색되었고, 용매분획에 따라 추출되는 향기성분의 함량과 조성은 차이가 있었으며, 추출방법에 따라서도 향 기성분의 조성비가 다르게 나타났다.

수평관내 증기분무류의 응축열전달에 관하여 실험을 행하고 상당 Reynolds수를 근거로한 열전달효과와의 비교에서 그 결과를 요약하면 다음과 같다. 1. 관내 응축증기 분무류일 경우의 벽면전단응력의 식은 다음과 같이 쓸 수 있다. root(τ하(0)/τ하(0v))=1+1.46X 하(tt) 상(0.20). 2. 분무류의 응축열전달효과가 상당 Reynolds수에 의한 값보다 대체로 낮게 나타난 이유는 관내 반경 및 길이방향의 불균일한 액막형성에 의한 Reynolds수 측정값의 차이 때문이다. 3. 분무류의 응축열전달효과에 의한 N sub(u)의 값은 다음과 같다. N 하(u)=1.08×[σ 하(l) d/μ 하(l)/δ+(2.5/P 하(rl)) ln(y 하(i)/δ)]×τ 하(0)/ σ 하(l) 상(1/2)

미래사회가 지향하는 창의융합형 인재를 육성하기 위해 『택리지』를 중심으로 공동탐구토론에 기반한 STEAM 프로그램을 개발하였다. ‘함께ㆍ깊게ㆍ둥글게 읽기(함깊둥)’ 활동은 참여 교사와 학생의 융합적 역량을 신장시키고, 협업적이면서 지속 가능하게 이루어질 수 있는 프로그램이다. 『택리지』를 읽고, 스스로 발견하거나 함께 공유한 아이디어를 반복해서 고찰하는 과정을 통해 창의적인 아이디어를 생성할 수 있었다. 함깊둥 활동을 통해 얻게 된 아이디어는 교사의 융합 수업 설계와 학생의 연구 활동 수행에 적용되었다. 지리교사는『택리지』의 가거지 조건과 오늘날의 가거지 조건을 비교하고, 지리공간서비스를 활용하여 선정한 지역의 도시 내부구조를 분석하며, 거주 공간의 특성을 설명하는 지리 중심 융합 수업을 운영하였다. 학생들은 『택리지』에서 연구할 만한 가치가 있는 수학ㆍ과학적 문제와 지리학의 학문적 가치를 발견하고, 이를 학생 주도의 연구 활동에 응용하였다. 현재 STEAM 교육에서 인문학적 상상력과 예술적 감성을 길러줄 수 있는 인문ㆍ예술 계열의 역할이 교육계 안팎으로 주목을 받고 있다. 앞으로 융합교육의 중요성을 고려할 때, STEAM 교육에 더 관심을 가지고 우리나라의 미래교육을 준비하는 데 보다 적극적으로 임할 필요가 있다.

세계는 매일 빠른 속도로 발전하며 기존의 기술이 서로 융합하여 복합적인 모습으로 성장하고있다. 이에 기존의 문제해결 방법으로는 해결할 수 없는 다양한 문제가 야기되었으며, 유연하게 해결하기 위한 '창의적 사고'를 가진 인재가 중요시 되고 있다. 그리하여 융합형 인재를 양성하기 위해 과학, 수학, 엔지니어링, 기술 등을 접목한 STEM교육과 4개의 내용(Science, Technology, Engineering, Mathematics)에서 예술(Art)을 합친 STEAM교육에 대한 인식과 교육방법이 연구되기 시작했다. 2010년 한국에도 STEAM교육이 접목되었으나, 대학 입시 위주의 교육 풍토상 과학, 수학의 내용이 강조된 불균형적인 형태로 STEAM교육이 이루어지고 있어 흥미를 일으키기 어렵고 학생 스스로가 참여하고 생각할 수 있는 수업이 부족하다. 이에 본 연구는 '창의적 사고'를 배양하는 디자인씽킹(Design Thinking) 프로세스를 도입하여 문제해결 능력을 체득하고, 협업을 통해 나를 포함한 공동체를 이해하는 인성함양 STEAM교육을 개발하였다. 개발된 비즈니스 창업 프로그램은 창의· 인성교육에 스토리텔링을 입혀 참여학생의 흥미도를 높여 자발적 참여가 가능하게 개발된 프로그램이다. 2018년 4개 중·고등학교에 교육 실시 후 만족도와 효과성 사후 조사를 실시하였으며 긍정적인 효과를 나타내었다. 향후 미래 융합인재 양성교육에 알맞는 창의적 사고를 배양하고, 인성교육을 통해 사회에 속한 개인의 문제뿐만 아니라 협업과 분업을 통한 기초소양을 체득화 하는 것에 도움이 될 것으로 기대한다.

최근 들어 VR 산업의 성장을 위한 양질의 VR 콘텐츠에 대한 필요성이 꾸준히 제기되고 있다. 이에 본 연구는 VR 콘텐츠 중에서 가장 큰 주목을 받고 있는 VR 게임의 사용자의 관심요소에 대해 연구하였다. 연구 수행을 위해 스팀(STEAM)의 사용자 리뷰 데이터를 활용하였고 리뷰 데이터에 텍스트마이닝과 네트워크 분석을 적용한 결과 VR 게임 사용자의 관심요소는 '현존감', '1인칭 시점 게임', '청각적 요소', '상호작용' 으로 확인되었다. 본 연구는 양질의 VR 게임 개발을 위한 사용자 관점의 연구를 수행하고 사용자 관점의 연구를 리뷰을 통해 시도한 초기 연구라는 것에 대해 그 의의가 있다.

This study investigated the effects of pressurized steam-treated Corni Frutus (PSC) extract on osteoblast differentiation and osteoclast formation. The osteoblast differentiation effect of the extract was evaluated by measuring cellular alkaline phosphatase (ALP) activity, cell matrix ALP staining, alizarin Red S staining and von Kossa staining on proliferating MC3T3-E1 osteoblast cells. The results confirmed that ALP activity, cell matrix ALP staining, alizarin Red S staining and von Kossa staining were all increased as proliferation increased from 1 to 14 days, without cytotoxicity. The osteoclast formation effect of the PSC extract was evaluated by measuring the cellular tartrate-resistant acid phosphatase (TRAP) activity and cell matrix TRAP staining on receptor activator of nuclear factor kappa-B ligand (RANKL)-induced RAW264.7 osteoclast cells. Treating RAW264.7 cells with RANKL for 7 days increased matrix staining for TRAP and cellular TRAP activity. The PSC extract decreased these changes in a concentration-dependent manner. Therefore, PSC is expected to be a natural source for developing health functional foods and medicinal agents to prevent bone-related diseases, such as osteoporosis, by increasing osteoblast differentiation and reducing osteoclast activity.

The aim of this study was to investigate functional food material for the antioxidant and biological activities of untreated and steam-treated Corni fructus extracts in extraction solvents (through hot-water extraction, 50% ethanol extraction, and 50% methanol extraction). The yield of UCH (hot-water extract of untreated Corni fructus) was 47.45% and it was higher than those of extracts (13.20-27.18%) obtained by the other extraction methods. The total phenolic and flavonoid contents were 12.23 g/100 g (SCE, 50% ethanol extract of steam-treated Corni fructus) and 5.08 g/100 g (SCE), respectively, and the total sugar content was 71.32 g/100 g (SCH, hot-water extract of steam-treated Corni fructus). The main organic acid components of the extracts were oxalic acid, citric acid, malic acid, formic acid, and gallic acid. The DPPH and ABTS radical scavenging activities of SCE at 1,000 μg/mL were 72.37% and 43.15%, respectively. The ferric-reducing antioxidant power of SCE at 1,000 μg/mL was 689.49 μM. The extracts were investigated for their function in L-132, RAW 264.7, HeLa, and MCF-7 cell lines. The SCE performed better than the other extracts in terms of its protective effects against oxidative stress in L-132 cells and increased the production of NO. Further the SCE showed antitumor activities against HeLa and MCF-7 cancer cells. Therefore, the SCE extracts is a good functional food material for the prevention of woman disease. Therefore, in our study, the SCE extracts is good functional food material for the prevention of oxidant, immunological, and tumor related disease.

This study was conducted to compare the volatile flavor compounds of Artemisia annua L. after extraction by simultaneous steam distillation extraction (SDE) and solid-phase micro extraction (SPME) followed by gas chromatography-mass spectrometry (GC-MS) analysis. Via SDE and SPME processes, 79 (1,254.00 mg/kg) and 39 (488.74 mg/kg) compounds were identified respectively. The compounds extracted by SDE included 27 alcohols, 13 aldehydes, 22 hydrocarbons, 3 esters, 12 ketones, 1 oxide and 1 N-containing compound, on the other hand, using the SPME method, 7 alcohols, 5 aldehydes, 1 ester, 18 hydrocarbons, 7 ketones, and 1 oxide were extracted. The major volatile flavor compounds of Artemisia annua L. isolated by the two methods were caryophyllene oxide, -caryophyllene, camphor, -selinene, -muurolene, 1,8-cineol, (E)-pinocarveol and pinocarvone. β β γ The sesquiterpene named caryophyllene oxide was the most abundant volatile flavor compound with relative contents of 234.16 mg/kg and 195.44 mg/kg obtained by the SDE and SPME methods, respectively. Among the identified volatiles, sabinene, β-pinene, α-terpinene, γ-terpinene, yomogi alcohol, myrtenol, (Z)-nerolidol, p-cymen-8-ol and eugenol were detected by the SDE method only while (E)-anethole and α-cubebene were detected by the SPME method only. This study confirmed that the composition and contents of the volatile flavor compounds vary between different extraction methods. More volatile flavor compounds were identified using the SDE method than the SPME method.

Background : The major components in Astragalus membranaceus are isoflavonoids, triterpene and polysaccharides. Also, isoflavonoids was composed to aglycon and glucoside derivatives. In this study, we performed fermentation process (enzyme treatment) and steam processing (high temperature and pressure) to increase aglycon such as formononetin and calycosin. Methods and Results : The steam processing was performed at a lot of conditions, such as temperature (80, 100, 120℃) and time (30, 60 and 120 min). Fermentation processing carried out by A. membranaceus extract fermented with microorganisms which have high β -glucosidase activity (selection by esculin agar method) for detached glucose from isoflavonoids, converted to algycon. The isoflavonoids were analyzed using high pressure liquid chromatography (HPLC) in fermentation product of A. membranaceu extract by treated with steam processing at various conditions. As a result of β-glucosidase activity by pNP assay, we selected three strains, Pediococcus pentosaceus, Weissella cibaria and Saccharomyces cerevisiae. Isoflavone aglycon was the highest in fermentation product by S. cerevisiae for 3 days, but change of isoflavonoids was not observed in steam processing. The calycosin-glucoside and ononin were reduced in fermentation product of A. membranaceus extract, whereas calycosin and formononetin was increased. Conclusion : This results showed that isoflavone glycoside converted to isoflavone aglycon in A. membranaceus by fermentation process, it seems to be available for industrial use.

Background: Hot steaming is known to be effective in improving the biological activities of plant extracts by breaking down useful compounds to low molecular weight ones. Methods and Results: This study aimed to develop an optimal extraction and steam processing method for enhancing the low molecular ginsenoside contents of the adventitious roots culture of wild mountain ginseng. The total ginsenoside was optimally extracted when 70% EtOH was used at 50℃, whereas low molecule ginsenoside such as Rg2, Rh1, Rh4 and Rk1 could be extracted using 70% EtOH at 70℃. The adventitious roots culture of wild mountain ginseng is known to contain four major ginsenosides, i.e., Rb2, Rb1, Rg1 and Rd, however new ginsenosides Rg6, Rh4, Rg3, Rk1 and Rg5 were new abundantly obtaind after steam processing method was applied. The contents of total ginsenosides were the highest when thermal steam processing was conducted at 120℃ for 120 min. Unlike ginsenosides such as Rg1, Re, Rb1, Rc, Rb2, and Rh1, which decreased after steam processing, Rg3, Rk1, and Rg5 increased after thermal processing. Steam processing significanltly reduced the content of Rb1, increased that of Rg6 by about ten times than that in the adventitious roots culture of wild mountain ginseng. Conclusions: Our study showed that the optimal extraction and steam processing method increased the content of total ginsenosides and allowed the extraction of minor ginsenosides from major ones.

Depending on the steam pressure and temperature balance, it is possible to increase the power generation efficiency of the steam turbine by increasing the heat loss of the turbine by increasing the temperature and pressure. As the high temperature and high pressure increase, the boiler main steam amount is reduced by about 10%, but the increase rate of the heat drop is larger than the decrease rate of the steam flow rate, leading to improvement of power generation efficiency. Utilizing the US Department of Energy Steam Turbine Calculator, we calculated the electricity produced by steam temperature and pressure changes. In this study, the steam temperature was increased from 50℃ to 500℃ at the steam temperature of 20 kg/cm²×300℃, and increased by 10 kg/cm² at the pressure of 20 kg/cm² at the pressure of 60 kg/cm² to investigate the changes in electricity production. Electricity production increased with increasing temperature and pressure. The electricity production was increased by 40.11% at 40 kg/cm²×400℃ and 75.56% at 60 kg/cm²×500℃ compared to the standard condition of 20 kg/cm²×300℃ for comparison.

Energy can be reduced by reducing the exhaust gas temperature at the catalyst inlet and reducing or not using the amount of steam to reheat the exhaust gas. At this time, it is a method to improve the power generation efficiency by using the saved energy for power generation. When the exhaust gas temperature at the inlet of the catalytic reaction tower is operated at about 210℃, it is necessary to increase the temperature of the flue gas downstream of the bag filter at 165℃ to 45℃ to 210℃ required for the catalytic reaction. In the case of low temperature catalyst application, the temperature required for the catalytic reaction tower may be 185℃ and the temperature may be raised only 20℃. Therefore, the amount of steam for heating can be reduced. If the exhaust gas temperature of the bag filter inlet can be increased to 190℃, it can be combined with the low-temperature catalyst to reduce the energy consumed by removing exhaust gas ash. On the other hand, since the high-pressure steam is used as the heat source for reheating the exhaust gas, the reheating temperature is limited. According to such conditions, the exhaust gas temperature at the inlet of the catalytic reaction tower is often designed at about 200 to 220℃.

최근 중질유 사용 비중이 높아짐에 따라 정유 플랜트의 정제공정에서 질소성분에서 유래된 다량의 암모니아가 황 회수시설로 유입되어 관 부식등의 문제를 일으켜 암모니아의 효율적 제거에 관심이 증가하고 있다. 암모니아 제거공정 중 Steam stripping은 스팀을 사용하여 충진탑에서 다성분의 액체가 공급되어 충진물을 타고 내려가며 스팀은 탑 아래에서 올라가며 암모니아가 스팀과 함께 증발해나오는 공정이다. 스팀을 사용하여 제거효율을 높일 수 있고 부산물로 암모니아수를 확보하여 소각로, 발전소 탈질설비의 환원제로 사용하여 시설 운영비를 절감할 수 있는 장점으로 연구개발에 착수하였다. 플랜트에서 암모니아는 보통 저농도로 존재하기 때문에 저농도에서 암모니아를 제거하여 회수하는데 초점을 맞췄다. 고농도에서 암모니아를 회수하는 데는 어려움이 없지만, 저농도에서 암모니아를 회수하기에는 수많은 조건이 따른다. Feed농도와 탑내로 주입하는 스팀양과의 비율, 주입스팀양에 따른 컨덴서에서의 응축량과 recycle되는 성분의 비율, 스팀양과 제거율, 회수암모니아수의 관계등의 조건을 최적화시킬 필요가 있다. 본 연구에서는 저농도 조건에서 높은 제거효율과 고농도의 암모니아수를 회수하는 최적화된 연구에 관하여 보고하고자한다.

This study was conducted to develop radish as a food product for home meal replacement using superheated steam (SHS). Also, the change of quality characteristics was studied during their storage. The radish cuts were treated with SHS for 0, 3, 5, and 7 min, respectively, followed by complete drying at 80℃ for 6 hours. The results showed that radishes restored with mixed solution (drinking water:sugar:vinegar:salt=2:1:0.8:0.1) were harder than those restored with drinking water. All radishes were stored at 5, 10 and 15℃ for 56 days to investigate the changes of quality characteristics during the storage. Radishes in the control group, restored with drinking water and stored at 15℃, were spoiled after 7 days of storage. The radish in the experimental group did not show any change in the water content; except an increase on the first day of storage. The hardness of radish decreased with an increase in the storage period. It was found that microbial growth was inhibited due to low pH of the mixed solution, in which radishes of the experimental group were immerse.

The objective of this study was to investigate the effect of superheated steam (SHS) and high hydrostatic pressure (HHP) techniques on the improvement of the quality of Bulgogi product during manufacturing process. Bulgogi product was treated with four different cooking/treatment process: conventional cooking (CC), SHS cooking (SHS), CC and then HHP cooking (CC-HHP), and SHS and HHP cooking (SHS-HHP) samples. SHS treated product increased moisture content, and decreased crude protein. Additionally, hardness, gumminess and shear force values were significantly different among the samples (p<0.05). In safety experiment after 14 days of storage at refrigeration temperature indicated that the bacterial population was lower in the case of SHS-HHP as compared to CC-HHP. Changes in texture during the storage periods at 10℃ for SHS-HHP was lowest values with compared to the initial, while shear force values for both tended to decrease with increasing storage period. The TBA and VBN values for SHS-HHP increased to 0.48 (5℃)-1.68 (10℃) mg MD/kg and 25.14 (5℃)-45.14 (10℃) mg%, respectively after 15 days of storage. Overall, it was found that the combination of SHS and HHP reduced microbial growth, thus leading to improved product quality and sanitation.

인터넷 환경의 발달로 소비자들 사이에 상품정보에 대한 의견이 교환되기 시작하면서 다양한 형식의 온라인 리뷰들이 급속도로 생성되고 있다. 이러한 추세에 따라, 기업들은 온라인 리뷰들 을 분석하여 마케팅, 세일즈, 제품개발 등의 다양한 기업 활동에서 그 결과를 활용하려는 노력 을 진행하고 있다. 그러나 대표적인 경험재인 ‘게임’과 관련된 산업에서의 온라인 리뷰에 대한 연구는 매우 부족한 실정이다. 이에 본 연구는 머신러닝 모델을 활용하여 스팀(STEAM)게임의 커뮤니티 데이터를 분석하였다. 이를 통해 타 사용자의 게임 리뷰를 유용하다고 판단하는데 영 향을 미치는 요인을 분석하고, 리뷰의 유용성을 예측하는데 있어 가장 우수한 성능을 보인 모 델과 변수들을 도출하여 사용자의 충성도와 사용성을 증대시키기 위한 제안을 하고자 한다.

The purpose of this study was to evaluate the effect of superheated steam drying on physicochemical and microbial characteristics of Korean traditional actinidia (Actinidia arguta) leaves. Actinidia leaves were dried at steam temperature of 350℃ and oven temperature of 150℃ for 40-200 sec. Moisture content and water activity decreased with increasing the drying time, while color values including L, a, and b values and total color difference (ΔE) increased as drying time increased. The relationship between moisture content and water activity showed an exponential fit with high correlation vlaue (R2=0.9909). Total phenolics and flavonoids content and antioxidant activity such as DPPH radical scavenging activity, ABTS radical scavenging activity, and FRAP assay of dried actinidia leaves increased with increasing the drying time up to 160 sec, but dramatically decreased at drying of 200 sec. The numbers of total areobic bacteria of leaves was not detected at drying time over 120 sec and coliform of all the samples was not detected. As a results, the superheated steam was an very effective drying method of increase to the nutritional and sanitary quality of dried Korean traditional actinidia leaves.