http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Dynamic Symmetrical Components Analysis and Compensation for Unbalanced Distribution Systems
Woei-Luen Chen,Bing-Syuan Lin,Meng-Jie Wang 전력전자학회 2015 ICPE(ISPE)논문집 Vol.2015 No.6
The short circuit fault and the unbalanced three-phase loads are the common reasons causing unbalanced voltage distortion (UVD) in the distribution system. In the past, the decline in electric motor performance and life cycle was a well-known fact caused by UVD. However, the UVD deserves more attention in recent years due to the rapid growth of the wind power penetration in the distribution system. The wind power system operated under the UVD suffers not only the pulsation torque but also penetrates unbalanced current and consequently deteriorates the UVD of the distribution system. This paper presents an approach to dynamically resolve the symmetrical components from the three-phase instantaneous voltages in order to clarify the degree of the UVD for compensation. The vector representation for the symmetrical components involves the information of angular frequency into the steady-state phasor, which can push much of the complexity down on the controller design for compensating the UVD. A dynamic voltage restorer (DVR) is employed as a voltage compensator in the series path of the feeder for refining the percent voltage unbalance of the UVD. The impact of the UVD reduction on a grid-tied 3-kW squirrel cage induction generator (SCIG) shows the effectiveness of the proposed approach.
( Chia Chin Liu ),( Jeng Woei Lee ),( Tso Tsai Liu ),( Chih Hsun Yi ),( Chien Lin Chen ) 대한소화기기능성질환·운동학회(구 대한소화관운동학회) 2013 Journal of Neurogastroenterology and Motility (JNM Vol.19 No.3
Background/Aims Detailed characterization of the ultrastructural morphology of intercellular space in gastroesophageal reflux disease has not been fully studied. We aimed to investigate whether subtle alteration in intercellular space structure and tight junction proteins might differ among patients with gastroesophageal reflux disease. Methods Esophageal biopsies at 5 cm above the gastroesophageal junction were obtained from 6 asymptomatic controls, 10 patients with reflux symptoms but without erosions, and 18 patients with erosions. The biopsies were morphologically evaluated by transmission electron microscopy, and by using immunohistochemistry for tight junction proteins (claudin-1 and claudin-2 proteins). Results The expressions of tight junction proteins did not differ between asymptomatic controls and gastroesophageal reflux disease patients. In patients with gastroesophageal reflux disease, altered desmosomal junction morphology was only found in upper stratified squamous epithelium. Dilated intercellular space occurred only in upper stratified squamous epithelium and in patients with erosive esophagitis.Conclusions This study suggests that dilated intercellular space may not be uniformly present inside the esophageal mucosa and predom - inantly it is located in upper squamous epithelium. Presence of desmosomal junction alterations is associated with increased severity of gastroesophageal reflux disease. Besides dilated intercellular space, subtle changes in ultrastructural morphology of intercellular space allow better identification of inflamed esophageal mucosa relevant to acid reflux. (J Neurogastroenterol Motil 2013; 19:324-331)
Mathematical Analysis of the Parallel Packet Switch with a Sliding Window Scheme
Liu, Chia-Lung,Wu, Chin-Chi,Lin, Woei The Korea Institute of Information and Commucation 2007 Journal of communications and networks Vol.9 No.3
This work analyzes the performance of the parallel packet switch (PPS) with a sliding window (SW) method. The PPS involves numerous packet switches that operate independently and in parallel. The conventional PPS dispatch algorithm adopts a round robin (RR) method. The class of PPS is characterized by deployment of parallel low-speed switches whose all memory buffers run more slowly than the external line rate. In this work, a novel SW packet switching method for PPS, called SW-PPS, is proposed. The SW-PPS employs memory space more effectively than the existing PPS using RR algorithm. Under identical Bernoulli and bursty data traffic, the SW-PPS provided significantly improved performance when compared to PPS with RR method. Moreover, this investigation presents a novel mathematical analytical model to evaluate the performance of the PPS using RR and SW method. Under various operating conditions, our proposed model and analysis successfully exhibit these performance characteristics including throughput, cell delay, and cell drop rate.
Lu-Yen Chen,Jo-Ming Tseng,Chung-Hwei Su,Kuen-Yuan Chuang,Chun-Ping Lin,Shuh-Woei Yu 한국화학공학회 2012 Korean Journal of Chemical Engineering Vol.29 No.10
Tert-butyl(2-ethylhexyl)monoperoxy carbonate (TBEHC) 95 mass% is intrinsically a very unstable substance that can induce self-decomposition even under normal atmospheric condition. During storage, TBEHC 95mass%can release an enormous amount of heat if the temperature is higher than the recommended storage temperature, due to the self-accelerating reaction having been ignited. In this study, TBEHC 95mass% was tested by differential scanning calorimetry (DSC) under five heating rates (1, 2, 4, 6, and 8 oC/min) and four isothermal conditions (120, 125, 130,and 135 oC) to evaluate the basic kinetic and safety parameters of time to maximum rate (TMR), self-accelerating decomposition temperature (SADT), and temperature of no return (TNR). Under runaway reaction TBEHC 95 mass%releases a great quantity of heat. This study establishes an important guiding principle for related manufacturing processes worldwide.