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A Study on LPG Spray and Combustion Characteristics
이성욱(Lee Seang-wock),Nagashima Naoki,Kusaka Jin,Daisho Yasuhiro 한국자동차공학회 2002 한국자동차공학회 춘 추계 학술대회 논문집 Vol.2002 No.5_1
It has been recognized that alternative fuels such as Liquid Petroleum Gas (LPG) less polluting combustion characteristics than diesel fuel. Furthermore, engine performance is expected to be nearly equal to that of the diesel engine both in thermal efficiency and power output. However the properties of LPG are quite different from those of diesel fuel. Understanding the characteristics of LPG spray and evaporating processes are very important for developing efficient and low emission LPG engines optimized in fuel injection control and combustion processes. In this study, the LPG spray characteristics and evaporating processes were investigated using the Schlieren optical system and single-hole injectors in a constant volume chamber at room temperature. Also the characteristics of combustion were investigated using simultaneous visualization of OH radical and flames. The results show that the mixture moves along the impingement wall that reproduced the piston bowl and reaches in ignition spark plug. Also, OH fluorescence rises sharply and then decreases gradually when the combustion is carried out actively.
Clinical Characteristics of Esophageal Motility Disorders in Patients With Heartburn
( Satsuki Takahashi ),( Tomoaki Matsumura ),( Tatsuya Kaneko ),( Mamoru Tokunaga ),( Hirotaka Oura ),( Tsubasa Ishikawa ),( Ariki Nagashima ),( Wataru Shiratori ),( Naoki Akizue ),( Yuki Ohta ),( Atsu 대한소화기기능성질환·운동학회 2021 Journal of Neurogastroenterology and Motility (JNM Vol.27 No.4
Background/Aims Esophageal motility disorders (EMDs) contribute to the pathophysiology of gastroesophageal reflux disease. However, the causes of EMDs and their impact on gastroesophageal reflux disease-associated symptoms remain unknown. This study aims to elucidate clinical features associated with various types of EMDs in patients with heartburn symptoms. Methods Of the 511 patients who underwent high-resolution manometry, 394 who were evaluated for heartburn symptoms were examined. Patients subjected to high-resolution manometry were classified into 4 groups: outflow obstruction group, hypermotility group, hypomotility group, and normal motility group. Symptoms were evaluated using 3 questionnaires. Patient characteristics and symptoms for each EMD type were compared with those of the normal motility group. Results Of the 394 patients, 193 (48.9%) were diagnosed with EMDs, including 71 with outflow obstruction, 15 with hypermotility, and 107 with hypomotility. The mean dysphagia score was significantly higher in each of the 3 EMD groups compared with those with normal motility. The mean acid reflux and dyspepsia scores were significantly lower in the outflow obstruction group (P < 0.05). The mean body mass index and median Brinkman index were significantly higher in the hypermotility group (P = 0.001 and P = 0.018, respectively), whereas the mean diarrhea and constipation scores were significantly lower in the hypomotility group (P < 0.05). Conclusions The results of our study indicate that different EMDs have distinct characteristics. Cigarette smoking and high body mass index were associated with esophageal hypermotility. Assessment of the dysphagia symptom scores may help identify patients with EMDs. (J Neurogastroenterol Motil 2021;27:545-554)