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        검색결과 1,095

        64.
        2021.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, we investigate the effect of the duration of mechanical alloying on the microstructures and mechanical properties of ODS ferritic/martensitic steel. The Fe(bal.)-10Cr-1Mo pre-alloyed powder and Y2O3 powder are mechanically alloyed for the different mechanical alloying duration (0 to 40 h) and then constantly fabricated using a uniaxial hot pressing process. Upon increasing the mechanical alloying time, the average powder diameter and crystallite size increased dramatically. In the initial stages within 5 h of mechanical alloying, inhomogeneous grain morphology is observed along with coarsened carbide and oxide distributions; thus, precipitate phases are temporarily observed between the two powders because of insufficient collision energy to get fragmented. After 40 h of the MA process, however, fine martensitic grains and uniformly distributed oxide particles are observed. This led to a favorable tensile strength and elongation at room temperature and 650oC.
        4,000원
        65.
        2021.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        멤브레인 기반의 MBRWG (Membrane Bioreactor for Waste Gas) 처리기술은 폐가스 흐름에 대한 높은 선택성을 바탕으로 효과적인 생물학적 제거를 수행할 수 있다. MBRWG에는 몇 가지 잠재적 이점이 있는데, 이 중 가장 두드러진 점은 기상과 액상이 멤브레인 양쪽으로 명확히 분리되어 액상 내 생물막의 최적제어가 용이하고 이를 통해 효과적인 생분해와 생물막의 활성화를 도모할 수 있다는 것이다. MBRWG 처리기술은 특히 xylene 같은 소수성 독성 기체 성분 제거에 유리한데 이는 소수성 기체의 물질전달속도, 독성 및 제거율이 생물막 인근의 액상흐름 및 수분제어에 민감하게 변화하기 때문이다. MBRWG 처리에 쓰이는 다양한 멤브레인 중에서 PDMS-중공사막(hollow fiber)이 가장 높은 기체 물질 전달을 제공한다고 보고되었다. Capillary 형태도 중공사막형태에 비해 비표면적은 낮지만 비교적 활발한 연구가 진행되고 있다. 소수성 기체성분 제거 외에도 기존 생물학적 폐가스 처리 장치에서 배출된 잔류 기체 혼합물이나 먼지를 제거하기 위한 후단 공정에서 멤브레인 활용을 고려할 수 있다.
        4,000원
        67.
        2021.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        목적 : 본 연구의 목적은 노인의 건강 기능 장애를 평가하기 위한 측정 도구의 문항을 개발하는 예비연구이다. 방법: 연구 과정은 4단계로 구성된다. 1단계 문항 추출과정, 2단계 추출된 문항과 ICF 모델과의 연결, 3단계 인지 및 신체기능 평가 항목의 델파이 조사, 4단계 전문가 집단 대상 심층 인터뷰 조사 순서로 진행 되었다. 1단계에서는 중국, 일본, 한국 각 국의 패널조사를 사용하여 인지 및 신체 건강 관련 평가 항목 을 추출하였다. 사용된 패널조사는 중국의 2013년 China Health and Retirement Survey과 일본의 2013년 Japanese Study of Aging and Retirement, 한국의 2012년 Korean Longitudinal Study of Aging이다. 2단계에서는 세 명의 연구자가 추출된 문항과 ICF의 세부항목과 연결시켰으며 3단계에서는 10명의 델파이 패널 집단을 대상으로 델파이 조사를 적용하여 2단계 과정의 적합성을 조사하였다. 델파이 설문조사에 참여한 전문가 집단은 총 10명이며 2021년 5월 1일부터 2021년 6월 15일까지 이메일을 통해 진행하였다. 델파이 조사를 통해 평가 항목의 구성타당도, 안정도 값을 산출하였다. 이후, 전문가 집단 중 3명을 선정하여 집중 인터뷰를 시행하였다. 결과: 중국, 일본, 한국 각 나라의 패널조사 중 신체 및 인지와 관련된 67문항을 추출했다. 추출된 문항과 ICF모델의 세부항목과의 적합성을 검증하기 위한 델파이 설문조사 결과, 구성타당도(CVR) 값이 0.8 이 하인 9개의 문항이 삭제되었으며 안정도 산출값은 모두 0.5이하로 분석되었다. 최종 선정된 문항은 59 문항으로 인지 영역 13개, 기본적 일상생활활동영역 9개, 수단적 일상생활활동영역 9개, 기타 활동영역 23개, 신체기능영역 5개이다. 결론: 본 연구에서는 중국, 일본, 한국 동북아 세 나라의 패널조사를 기반으로 노인의 건강 기능평가를 위한 세부항목을 추출하고 타당도를 검증했다. 본 연구는 작업치료사의 관점에서 노인의 건강 기능을 평가하기 위해 평가항목을 추출했다는 데 의의가 있다. 본 연구를 통해 도출된 평가항목은 ICF 세부항목을 기반으로 노인의 건강 기능을 평가할 수 있는 평가도구 개발에 기초 자료로 사용될 수 있을 것이다.
        5,200원
        68.
        2021.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study investigated various levels of sodium nitrite and probiotics (SNPro) combination as an alternative to zinc oxide on the growth performance, immune response, intestinal microflora, and morphology of weaned pigs. One hundred and ninety-two weaned pigs (Landrace×Yorkshire×Duroc) with an average body weight of 6.51±0.15 kg were randomly assigned to four treatments(n=6) on the basis of their initial body weight. Experimental period was divided into phase 1 and 2 (each 14 days). The dietary treatments were: 1) Basal diet (control), 2) SNPro1 (control+0.01% SNPro), 3) SNPro2 (control+0.02% SNPro), 4) SNPro3 (control+0.03% SNPro). The average daily gain when SNPro was added to the diet was 288, 309, 319, 324 g in phase 1, 355, 387, 410, 407 g in phase 2 and 321, 348, 364, 366 g in the overall. The concentration of interleukin-8 and interleukin-10 in serum when SNPro was added to the diet were 15, 13.5, 13, 12.8 ng/ml and 165, 162, 155, 145 ng/ml (p<0.05) but toll-like receptor 4 and immunoglobulin G levels in serum were no significantly different. The colonization of Escherichia coli in the ileum and Salmonella spp. in the caecum were significantly decreased as SNPro level increased (p<0.05). However, the population of Lactobacillus spp. did not differ among the groups. Although villus height and villus height to crypt depth ratio were not significantly affected by the treatments, crypt depth in the jejunum was 599, 586, 615, 599 ㎛ as SNPro level increased (p<0.05). In conclusion, SNPro had beneficial effects on growth performance, immune response, intestinal microflora and morphology weaned pigs. Therefore, SNPro not only can be considered as an alternative for the pharmacological level of zinc oxide in weaning pigs but also ideal dietary SNPro level was 0.02%.
        4,000원
        69.
        2021.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was conducted to determine the effects of dietary protein level and supplementation of protease on growth performance, nutrient digestibility, gut microflora, intestinal morphology and fecal noxious gas emission in weanling pigs. A total of 240 weaned pigs (Landrace×Yorkshire×Duroc, 5.82±0.3 kg) were used during 4 weeks in 2 phases (days 0-14, phase 1; and days 15-28, phase 2) feeding program based on age and initial body weight. Pigs were allocated to 2×2 factorial arrangement, including 2 protein levels (HP, high protein; LP, low protein) and 2 protease levels (with or without protease). The average daily gain in the LP treatment (357 g/d) was increased rather than the HP treatment (339 g/d). A greater avarage daily gain was observed in dietary suppiemented protease treatment (358 vs 339 g/d). Average feed intake was greater in the LP treatment (544 g/d) rather than the HP treatment (530 g/d). A greater average daily feed intake was observed in dietary supplemented protease treatment (552 vs 523 g/d). Dry matter and crude protein digestibility were increased in dietary supplemented protease treatment (82.62% and 76.08%, respectively) rather than non-supplemented treatment (81.74% and 75.13%, respectively). Ileal Lactobacillus spp. count increased in dietary supplemented protease treatment (7.42 vs 7.32 log10CFU/g). Emission of H2S was decreased in the LP treatment (4.41 ppm) rather than HP treatment (4.78 ppm). Emission of NH3 was decreased in dietary supplemented protease treatment (10.43 ppm vs 11.76 ppm). In conclusion, the decrease of dietary protein level and supplementation of protease had beneficial effects on growth performance, nutrient digestibility, gut microflora, and noxious gas emission in weanling pigs.
        4,000원
        70.
        2021.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, the effect of forage sources in the total mixed ration (TMR) on in vitro goat rumen fermentation was investigated. Rice straw (RS), Italian ryegrass (IRG), timothy (TIM), and alfalfa (ALF) were used as forage sources. Each forage source was mixed with a commercial goat concentrate diet in the ratio of 1:1. Total 4 TMR were prepared. Rumen simulated in vitro fermentation using goat rumen fluid collected from the slaughterhouse was conducted until 72 th . For fermentation parameters, gas production (GP), volatile fatty acids (VFAs), and ammonia nitrogen (NH3-N) were examined. All assays were performed at 24 th , 48 th , and 72 th h of incubation individually. Contents of crude protein and non-fibrous carbohydrate were greater in the order of RS < IRG < TIM < ALF. Significant treatment effects were found in valerate and NH3-N at 24 th h of incubation (p<0.05). ALF showed the greatest contents of them and RS was the lowest. At 48 th incubation, a significant effect was detected at GP (p<0.05) and RS was greater than others. However, GP of RS was lower than others at 72 th . Significant effects on Total VFA, butyrate, and valerate productions were found at 72 th h of incubation (p<0.05). ALF showed the greatest production. Methane production from all treatments was not significantly different for each incubation time (p>0.05). The present study provided primary information on how goat rumen fermentation responds to different nutrient contents and forage sources of TMR. And the information could be used for the design or optimizing economical diet formulation for goats.
        4,000원
        75.
        2021.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study was to investigate the changes in the content of functional components and the antioxidant activity of cooked rice and porridge composed of selected grains. The results of the study showed that brown rice and oat contained considerable amounts of γ-oryzanol (78.099~238.566 mg/100 g). However, cooked rice showed a decreased content of the same. The highest content of γ-aminobutyric acid (GABA) was observed in brown rice from Samgwang. The contents of biotin in all samples also decreased in cooked rice compared to raw cereal grains. The highest content of total polyphenols and flavonoids were observed in Heukjinmi rice, and the highest radical scavenging activity was also found in this variety. The cooking process led to a decrease in the content of functional components including γ-oryzanol, GABA, biotin, polyphenols, and flavonoids versus the corresponding raw cereal grains. These results may be useful in the development and application of home meal replacements using cereal grains.
        4,000원
        76.
        2021.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Vegetable oils are a rich source of bioactive substances. Phytosterols in those have been known for many years for their properties for reducing blood cholesterol levels, as well as their other beneficial health effects. Phytosterols are triterpenes that are important structural components of plant cell membranes just as cholesterol does in animal cell membranes. The aim of this study was to provide consumers with information about phytosterol contents in vegetable oils in Korea market. The contents of major phytosterols (campesterol, stigmasterol, β-sitosterol) in 50 vegetable oils of 10 kinds (perilla oil, peanut oil, avocado oil, olive oil, pine nut oil, sesame oil, canola oil, coconut oil, grape seed oil, and sunflower oil) were analyzed by gas chromatography with flame ionization detector. The average contents of vegetable oils containing 5 or more samples were in the order of sesame oil (334.43 mg/100 g), perilla oil (262.16 mg/100 g), grape seed oil (183.71 mg/100 g), and olive oil (68.68 mg/100 g). Phytosterol content of sesame oil and perilla oil was high among vegetable oils.
        4,000원
        79.
        2020.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, chemical information on a total of 20 individual compounds was constructed to identify isoflavones from the previous reports related with used parts(seeds, leaves, stems, pods) and products of soybean(Glycine max L.). Through constructed library and UPLC-DAD-QToF/MS analysis, a total of 19 individual isoflavones including aglycones, glucosides, acetylglucosides and malonylglucosides as major compounds was identified and quantified from 14 selected soybean seeds. Among them, genistein 7-O-(2"-O-apiosyl)glucoside and genistein 7-O-(6"-O-apiosyl)glucoside(ambocin) were identified tentatively as novel compounds in soybean seeds. Besides, among malonylglucosides, glycitein 4'-O-(6''-O-malonyl)glucoside was estimated for the first time. Total isoflavone contents were distributed from 240.21 to 445.21(mg/100 g, dry matter) and 7-O-6''-O-malonylglucosides were composed of 77.8% on total isoflavone as well as genistein derivatives were confirmed as major class. It was considered importantly that the development of isoflavone-rich varieties was necessary to strengthen their effects such as anti-inflammation, anti-cancer and menopause mitigation. The qualitative and quantitative data presented precisely in this study could be help to select and breed isoflavone-rich varieties. Furthermore, their basic isoflavone profile is expected to be applied to estimate the change of isoflavone conjugates on bioavailability after soy food supplements.
        4,200원
        80.
        2020.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Deep learning models, which imitate the function of human brain, have drawn attention from many engineering fields (mechanical, agricultural, and computer engineering etc). The major advantages of deep learning in engineering fields can be summarized by objects detection, classification, and time-series prediction. As well, it has been applied into environmental science and engineering fields. Here, we compiled our previous attempts to apply deep learning models in water-environment field and presented the future opportunities.
        4,500원
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