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        검색결과 459

        81.
        2016.05 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Fluorine-doped tin oxide (FTO) nanoparticles have been successfully synthesized using ultrasonic spray pyrolysis. The morphologies, crystal structures, chemical bonding states, and electrochemical properties of the nanoparticles are investigated. The FTO nanoparticles show uniform morphology and size distribution in the range of 6-10 nm. The FTO nanoparticles exhibit excellent electrochemical performance with high discharge specific capacity and good cycling stability (620mA h g−1 capacity retention up to 50 cycles), as well as excellent high-rate performance (250 mA h g−1 at 700mAg−1) compared to that of commercial SnO2. The improved electrochemical performance can be explained by two main effects. First, the excellent cycling stability with high discharge capacity is attributed to the nano-sized FTO particles, which are related to the increased electrochemical active area between the electrode and electrolyte. Second, the superb high-rate performance and the excellent cycling stability are ascribed to the increased electrical conductivity, which results from the introduction of fluorine doping in SnO2. This noble electrode structure can provide powerful potential anode materials for high-performance lithiumion batteries.
        4,000원
        82.
        2016.05 구독 인증기관 무료, 개인회원 유료
        In our country, the number of coffee shops has steadily increased, reaching approximately 15,000 in 2013 from 1,254 in 2006. Adding to increase of coffee shops, customers' preference of roasted beans and extraction to ready-made coffee or instant coffee has lead to rapid expansion of roasted coffee market. In this study, a prototype of the ultrasonic automatic packer that is consist of coffee beans input device, coffee beans filling device, filter paper input device, vertical & horizontal ultrasonic sealing device, conveyor input device, input sealing device of outer packaging, cutting device, and control system besides related devices has been designed and produced.
        4,000원
        84.
        2016.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The aim of this study was to compare ultrasonic measured traits (Eye muscle area : EMA, backfat thickness : BF and marbling score : MS) of Hanwoo cows by months of age and periods around 1st calving. The data used in this study were taken 2,636 cows which were measured from 20 months old to 28 months old and within 5 months around 1st calving. According to comparison of cows' month of age, ultrasonic measured EMA, BF and MS were not significantly different between 21 months old and 26 months old, 21 months old and 25 months old and 23 months old and 27 months old, respectively. According to comparison of periods around 1st calving, ultrasonic measured EMA, BF and MS were not significantly different between -45 days and 30 days, -15 days and 75 days, -105 days and 90 days around 1st calving, respectively. The selection of cows could be possible based on the phenotypic ultrasonic measurement performance if the traits are measured between 23-month old and 25-month old and between - 15 days and 30 days around 1st calving.
        4,000원
        85.
        2015.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        수술 후 체액 저류는 췌십이지장절제술 후 발생할 수 있는 중요한 합병증 중 하나로 이로 인해 사망률과 재원 기간이 증가할 수도 있다. 초음파내시경 유도 하 배액은 췌장 가성낭종의 치료 방법 중 하나이며 최근에는 수술 후 발생한 체액 저류 치료에 있어서도 성공적인 사례들이 보고되고 있다. 60세 여성이 한 달 동안 4 kg의 체중감소와 5일 전 부터 발생한 황달을 주소로 내원하였다. 복부 전산화단층 촬영 및 내시경 역행성 담췌관 조영술을 이용한 조직검사를 통하여 총담관암이 진단되어 췌십이지장절제술을 시행하였고 수술 2주째 발열, 복통, 백혈구 증가의 임상증상을 보였다. 진단을 위해 시행한 복부 전산화단층촬영에서 소낭의 위오목에 체액저류가 증가하여 내시경적 배액술을 시행하였고 이후 합병증 없이 증상이 호전되었다. 국내에서는 아직 췌십이지장절제술 후 발생한 체액 저류를 내시 경적 배액으로 치료한 증례가 보고된 바 없기에 문헌 고찰과 함께 보고하는 바이다.
        4,000원
        86.
        2015.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Quantitative analysis of termites damage is important in terms of conservation and maintenance of wooden cultural heritage buildings, because termites makes cavities and decreases the section area of wooden structural members. The purpose of this study is to forecast the range and spread of termites damage in the wooden structural members by using ultrasonic pulse velocity method. Ultrasonic pulse velocity has been used as one of non-destructive test to analysis the internal defect by using difference velocity between medium material and cavity. This method would be effective to analysis termites damages. From the result of the ultrasonic velocity test, the loss rate of area effected by termites damage had a strong correlation with ultrasonic velocity. And it is possible to predict the loss rate of area from by termites damage by using regression equation in the case of structural member of fine tree.
        4,000원
        88.
        2015.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Target strength (TS) information is an important parameter that estimates the detection, distribution, and abundance of Aurelia aurita. In order to investigate the biological TS of jellyfish, some factors such as size (bell diameter), tilt angle, pulsation, and symbion should be known. In the ex situ TS measurements, the tilt angles and pulsation from synchronized swimming behavior of four live A. aurita (bell diameters in the air: 54.2 ~ 94.2 mm) were measured with the acoustic data at 70 kHz. The reduced target strength (RTS) of A. aurita was found to change ranged from 13.4 ~ 16.5 dB according to the incidence angles from –30° to 24°. When the change rate of bell diameter in the water was 0.2, the TS value showed a 7.2 dB change. These results could be utilized as an important data to understand the acoustic characteristic scattering of A. aurita.
        4,000원
        89.
        2015.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 강산성차아염소산수(SAHW)와 초음파(UW)를 병용한 조미오징어 반가공품의 미생물 오염도 저감 기술을 개발하고자 수행되었다. SAHW의 유효염소농도는 69.67 ± 0.58 ppm, ORP는 1071.33 ± 4.16 mV, pH는 2.79 ± 0.05이었다. 오징어 반가공품을 중량대비 20배의 SHS에 120분간 침지하였을 때 일반세균은 1.49 log CFU/g, 황색포도상구균은 1.32 log CFU/g 감소하였으며, 대장균은 검출한계 이하로 감소하였다. 오징어 반가공품 중량대비 10배의 SAHW에 120분간 침지한 경우, 일반세균은 2.69 log CFU/g, 황색포도상구균은 1.74 log CFU/g 감소하였으며, 20배의 SAHW에 120분간 침지한 경우, 일반세균은 3.62 log lCFU/g, 황색포도상구균은 3.22 log CFU/g 감소하였으며, 대장균은 검출되지 않아 SAHW가 같은 유효염소농도의 SHS보다 살균력이 높은 것을 알 수 있었다. SAHW 단독 처리만으로는 만족할 만한 미생물 저감효과를 얻을 수 없었기에 조미오징어 반가공품을 SAEW에 1차 침지 처리한 후, SAHW에 2차 침지 처리한 결과, 오징어 반가공품 중량 대비 20배의 SAEW로 60분 처리한 후, SAHW로 처리하였을 때는 중량대비 10배, 120분 처리, 중량대비 20배, 90분 처리로 일반세균수는 약 4.0 log CFU/g, 황색포도상구균은 규제치(log 2.0 CFU/g 이하) 이하로 감소하였으며 대장균은 검출되지 않았다. 초음파 세정기에 오징어 반가공품과 중량대비 20배의 TW, SHS, SAHW를 각각 넣어 UW 처리한 후 미생물 오염도를 조사한 결과, SAHW로 60분간 처리하였을 때 일반세균은 검출한계(< 1.00 log CFU/g) 이하로 감소하였으며 황색포도상구균은 규제치 이하로 감소하여 가장 좋은 저감효과를 나타내었다. 대장균의 경우, SAHW 10분간 처리로도 검출한계 이하로 감소하여 SAHW와 UW의 병용이 조미오징어 반가공품 미생물 저감화에 가장 효과가 좋은 것을 알 수 있었다.
        4,000원
        93.
        2015.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The effects of ultrasound and enzyme treatments on reducing sugar production from Korean 6-row barley Dahyang during the mashing process of brewing were studied. The concentration of reducing sugar produced by the traditional method was 41.5 mg/mL. The treatment of both the ultrasound at 400 W and amyloglucosidase (0.1 U/mL) increased the reducing sugar concentration produced in the mashing process by 15% compared to the traditional method. In addition, both treatments reduced the total mashing time from 115 min to 70 min. The combination of ultrasound and amyloglucosidase treatment increased the reducing sugar production yield by 17% during mashing, in comparison with the traditional method.
        4,000원
        94.
        2015.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, cobalt nanopowder is fabricated by sonochemical polyol synthesis and magnetic separation method. First, sonochemical polyol synthesis is carried out at 220oC for up to 120 minutes in diethylene glycol (C4H10O3). As a result, when sonochemical polyol synthesis is performed for 50 minutes, most of the cobalt precursor (Co(OH)2) is reduced to spherical cobalt nanopowder of approximately 100 nm. In particular, aggregation and growth of cobalt particles are effectively suppressed as compared to common polyol synthesis. Furthermore, in order to obtain finer cobalt nanopowder, magnetic separation method using magnetic property of cobalt is introduced at an early reduction stage of sonochemical polyol synthesis when cobalt and cobalt precursor coexist. Finally, spherical cobalt nanopowder having an average particle size of 22 nm is successfully separated.
        4,000원
        95.
        2014.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this report is to discuss the obtained findings gathered from ultrasound screenings of the liver. After running diagnostic tests health, screens were then conducted to analyze and compare the gained results. This data was then charted and used to strengthen our theorized hypothesis. From January 2013 to June 2013 a recorded 2906 people over the age of 20 visited Health Promotion Centers in various areas throughout Daejeon. Of those 2906 participants 1789 underwent screenings for abdominal ultrasonography; these participants as well as their ultrasound results were used as the bases of our study. For the establishment of our baseline and the comparison of our results, we gathered case-controlled studies from various reputable sources. Both the control and the experimental groups were tested to measure the following liver enzymes (AST, ALT, r-GTP, ALP, and etc.). Kidney functions were measured as well enzymes such as BUN, Creatinine, and Uric Acids levels were analyzed and recorded to see if any relationships existed between the levels documented in the liver and those in the kidneys. It was shown that the two primary causes of fat build up within the liver were significantly connected to obesity BMI(OR=4.14) and waist circumference(OR=3.88).
        4,000원
        96.
        2014.09 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        췌장 가성 낭종의 종격동 침범은 매우 드문 췌장염의 합병증이다. 췌장염 환자가 비전형적인 흉통이나, 호흡곤란, 삼킴곤란 등을 호소하면 이 질환을 의심해 봐야 한다. 종격동 췌장 가성 낭종은 심각한 합병증을 초래할 수 있으므로 빠른 진단과 적절한 처치가 중요하다. 비록 현재까지 제한적으로 시행된 시술이지만, 종격동 가성 낭종에서 초음파 내시경 유도 배액술은 기술적으로도 가능하고 외과 수술보다 덜 침습 적이며 효과적인 배액술이라 할 수 있다. 이러한 종격동 침범 가성 낭종의 치료를 위한 다양한 내시경 배액법의 효과와 안전성에 대한 추가적인 연구가 요구된다.
        4,000원
        97.
        2014.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Much research into fuel cells operating at a temperature below 800℃. is being performed. There are sig-nificant efforts to replace the yttria-stabilized zirconia electrolyte with a doped ceria electrolyte that has high ionic con-ductivity even at a lower temperature. Even if the doped ceria electrolyte has high ionic conductivity, it also shows highelectronic conductivity in a reducing environment, therefore, when used as a solid electrolyte of a fuel cell, the power-generation efficiency and mechanical properties of the fuel cell may be degraded. In this study, gadolinium-doped ceriananopowder with Al2O3 and Mn2O3 as a reinforcing and electron trapping agents were synthesized by ultrasonic pyrol-ysis process. After firing, their microstructure and mechanical and electrical properties were investigated and comparedwith those of pure gadolinium-doped ceria specimen.
        4,000원
        98.
        2014.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        초음파는 비가청영역에서 나는 사운드이며 일상생활에서는 들을 수 없다. 초음파는 22kHz 이상의 주파수를 말하며 또한 이러한 성분을 초음파 성분 HFCs(High Frequency components)라고 한다. 파도소리는 사람에게 안정감 과 알파파를 유도한다고 알려졌는데 이러한 이유는 파도소리에 초음파 성분이 매우 많다는 것이다. 이러한 초음 파가 파도소리와 합쳐질 때 쾌감을 주고 알파파 증가와 베타파가 감소하는 초고주파효과(hypersonic effect)라고 한다. 본 실험에서는 파도소리를 들려주면서 동시에 파도소리에 해당되는 초음파부분을 전자회로로 설계하여 인위적으로 파도소리의 초음파 성분과 유사하도록 제작하여 실험하였다. 뇌파는 8채널을 사용하여 Fp1, Fp2, F3, F4, T3, T4, O1, O2 의 총 8개 전극을 부착하였다. 뇌파에서는 집중이나 긴장이완 등이 나타날 때 알파파가 나타 나며 각성상태나 긴장상태 그리고 스트레스상태에서는 주로 베타파가 나타난다. 초음파 실험결과 연구대상자들 의 알파파가 증가하고 베타파가 감소하는 현상이 통계적으로 유의미하게 나타났으며 초고주파현상이 반영되는 결과가 나타났다.
        4,000원
        99.
        2014.06 구독 인증기관 무료, 개인회원 유료
        While Ardisia crenata Sims. recently has been used increasingly as an ornamental plant, It is endangered in natural forest. The optimum treatments of the various concentrations priming agents to improve seed viability and germination of A. crenata (ornamental plant) were also estimated. Germinability was significantly when the seeds of A. crenata was soaked in PEG solution at 15oC for 4 days, the optimum treatment for improving germination of A. crenata was observed when the tested seeds was soaked in −0.5 MPa of PEG solution in 92%. Overall results would be useful means for propagation and production of A. crenata.
        4,000원
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