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동기전동기의 안정된 운전을 위한 퍼지 부하각 제어 시스템에 관한 연구
이관태,김경엽,이준탁 동아대학교 정보기술연구소 2007 情報技術硏究所論文誌 Vol.14 No.2
The basic construction of a synchronous motor is four components ; a stator, a rotor, bearings, and either a generator(brushless) or a static exciter(brush-type). In case of driving in motor mode, full-out characteristics of synchronous motor occur as a result of instantaneous overload to stable synchronous motor performance. A synchronous motor has performance like a induction motor in first starting period, but does a constant slip afterward. If a DC current applies to a field coil near the synchronous velocity, a synchronizing torque appears to the field coil. However, the lack of synchronizing torque often leads to a load angle instability in full-in. The failure of full-in or the full-out take a fatal influence to a power ratio, and a stability of system. As a load angle of a synchronous motor is controlled with the DC current, it is possible to prevent from the hazardous situation which is referred to previously and drive a synchronous motor stably. In this paper, load angle is extracted with proposed method and as applying fuzzy control technology for u-processor PIC16F874 stable driving of Synchronous Motor is intended.
열가소성 Wood-Plastic Composites의 기계적 물성에 미치는 커플링제의 영향
윤태호,신경섭,황택성,이존태 공주대학교 자원재활용 신소재 연구센터 1999 1차년도 센터 성과집 Vol.1999 No.-
목분 충진제의 함량을 달리 하고 PE수지를 매티릭스로 하여 wood plastic composites(WPC)를 제조하였다. 또한 매트릭스와 충진제간의 계면결합력을 증가시키기 위하여 커플링제로 phthalic anhydride(PA)를 사용하였으며, 충진제의 충진률과 커플링제 처리가 복합재의 기계적 물성에 미치는 영향과 계면현상을 관찰하였다. 목분의 충진률 30wt%, PA커플링제농도 3wt%일 때 인장강도는 26.37MPa로 최대값을 나타내었으며, 이때 충격강도는 46.24J/m의 최대값을 나타냈다. 또한 WPC는 주사전자현미경 관찰을 통해서 커플링제의 처리농도의 증가에 따라 목분과 PE 수지와의 분산과 결합이 잘 이루어졌으을 확인할 수 있었다. Wood powder as reinforcing fillers and polyethylene as a matrix have been used for wood plastic composites(WPC). In preparing WPC, the coupling agent, phthalic anhy dride(PA) was used in order to increase the interfacial bonding force between matrix and fillers. In this study, the effect of wood powder, PA concentration on the mechanical properties and interfcial phenomena on the composites was eveluated. The tensile strength of 3wt% PA-treated composites reached its maximum value of 25.91 MPa when the wood powder content was 30wt%, and the mximum impact strength of PA-treated composites was 46.24H/m. SEM observation showed that wood powder was well dispersed and bonded well with PE matrix by increasing the coupling agent concentration.
Lee, Kyu Tae,Hong, Seongjin,Lee, Jung Suk,Chung, Kyu Hyuck,Hilscherov?, Klara,Giesy, John P,Khim, Jong Seong Ecomed 2013 Environmental science and pollution research inter Vol.20 No.12
<P>While the World Health Organization 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) equivalency factors are useful estimates of relative potencies of mixtures when conducting risk assessments, they are not useful when comparing the results of bioassays such as the H4IIE-luc to concentrations of TCDD equivalents calculated from instrumental analyses. Since there are thousands of dioxin-like compounds (DLCs), one use of screening assays is to determine if all of the aryl hydrocarbon receptor (AhR) active DLCs in a mixture have been accounted for in instrumental analyses. For this purpose, bioassay-specific relative potency (ReP) values are needed. RePs of 21 polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans, and dioxin-like polychlorinated biphenyls that exhibit effects mediated through the AhR were determined by use of the H4IIE-luc assay. Different values of RePs are derived, depending on the statistical, curve-fitting methods used to derive them from the dose-response relationships. Here, we discuss the various methods for deriving RePs from in vitro data and their assumptions and effects on values of RePs. Full dose-response curves of 2,3,7,8-TCDD and other representative DLCs were used to estimate effective concentrations at multiple points (e.g., EC20-50-80), which were then used to estimate ReP of each DLC to 2,3,7,8-TCDD.</P>
Optimization of Analytical Procedure for Hydrogen Cyanide in Mainstream Smoke
Lee, John-Tae,Kim, Hyo-Keun,Hwang, Keon-Joong,Jang, Gi-Chul,Lee, Jeong-Min,Kim, Ick-Joong The Korean Society of Tobacco Science 2007 한국연초학회지 Vol.29 No.2
Hydrogen cyanide(HCN), formed from pyrolysis of various nitrogenous compounds such as protein, amino acids and nitrate in tobacco, is present in both the particulate phase and vapor phase of cigarette smoke. Typically the determination of HCN in cigarette smoke has been done through colorimetric and electrochemical techniques, such as fluorescence spectrometry, UV-spectrophotometry (UV), continuous flow analyzer (CFA), capillary GC-ECD and ion chromatography (IC). Most of these techniques are known to be time-consuming and some of them lack specificity or sensitivity. The available results from both our laboratory and reported literatures for 2R4F Kentucky reference cigarette, smoked under ISO condition, show a relatively wide variation ranging from 100 to 120 ug/cig of HCN. Especially, the precision and accuracy of the analytical results of HCN tend to get worse in low tar cigarettes and under intense smoking condition. In this paper, a more optimized analytical methods than previous ones are suggested. This method shows lower detection limit and has improved precision and accuracy, so it is applicable for wide tar level cigarettes under intense smoking condition as well as under ISO smoking condition. Important features of this method are improved sample collection and quantification systems such as the number of trapping units, volume, temperature and type of trapping solution. To avoid volatilization loss of HCN in analyzing mainstream smoke, it is highly recommended that pH values of trapping solutions should be maintained over 11 and cold traps should be used in collecting mainstream smoke.
Lee, Seung-Hun,Kim, Ha-Young,Lee, Haeseung,Kim, Jong Wan,Lee, Yu-Ran,Chae, Myeong Ju,Oh, Sang-Ik,Kim, Jong Ho,Rhee, Man Hee,Kwon, Oh-Deog,Goo, Youn-Kyoung,Kim, Tae-Hwan,Geraldino, Paul John L,Kwak, Do BMJ Group Group Ltd 2018 The Veterinary record Vol.183 No.16
<P>This study evaluated the prevalence of <I>Eimeria</I> species, particularly <I>E bovis</I>, <I>E zuernii</I> and <I>E auburnensis</I> that are pathogenic to cattle, in faecal samples collected from cattle with diarrhoea reared in the Republic of Korea by using microscopy and PCR. In addition, the prevalence of <I>Eimeria</I> species was analysed according to age, type of cattle, region, season and nature of diarrhoea. Overall, <I>Eimeria</I> species were identified in 279 of the 1261 (22.1 per cent) faecal samples through microscopy, and statistical analysis revealed a lower prevalence in calves aged than three weeks or less and higher prevalence in cattle with haemorrhagic diarrhoea. Of the 279 microscopy-positive samples, <I>E bovis</I>, <I>E zuernii</I> and <I>E auburnensis</I> were identified in 100 (7.9 per cent), 83 (6.6 per cent) and 27 (2.1 per cent) faecal samples, respectively, by using PCR. To the authors' knowledge, this study is the first to apply PCR for epizootiology of bovine coccidiosis.</P>
증례 : 담관 낭종 환자에서 발생한 선종 기원의 조기 담관암 1예
이태승 ( Tae Seung Lee ),김해경 ( Hae Kyung Kim ),안홍민 ( Hong Min Ahn ),이우주 ( Uh Joo Lee ),최영철 ( Young Chul Choi ),전병민 ( Byung Min John ),박태일 ( Tae Il Park ),구진회 ( Jin Hoi Koo ) 대한소화기학회 2009 대한소화기학회지 Vol.54 No.1
Choledochal cyst is an uncommon premalignant anomaly. The morphology and pathogenesis of the premalignant lesion of cholangiocarcinoma arising from the choledochal cyst has not been well described. Herein, we report a rare case of bile duct adenoma arising from choledochal cyst with anomalous union of pancreaticobiliary duct (AUPBD). 50-year-old woman was admitted to our hospital with the complaint of epigastric pain. She had received common bile duct (CBD) exploration and choledocholithotomy and cholecystectomy 3 months earlier under the diagnosis of multiple CBD stones. Intraoperalive cholangiogram was not remarkable except CBD dilatation at that time. Endoscopic retrograde cholangiopancreatography revealed choledochal cyst with AUPBD and round filling defect which disappeared easily on the balloon cholaniogram. On magnetic resonance cholangiopancreatography, the filling defect was confirmed as 2 cm polypoid mass attached to the distal bile duct wall. At laparotomy, a soft whitish mass was palpable on the lower CBD. On histological examination, adenoma with focal carcinoma change arising from choledochal cyst was diagnosed. (Korean J Gastroenterol 2009;54:55-59)