目的:分析超声在重症患者不同部位下下腔静脉内径及塌陷指数中的应用价值。方法:选取2022年1月—2023年1月入住上饶市人民医院重症监护室(Intensive Care Unit,ICU)45例患者,超声监测患者剑突下及右侧腹腋中线图像,测量患者不同部位下...目的:分析超声在重症患者不同部位下下腔静脉内径及塌陷指数中的应用价值。方法:选取2022年1月—2023年1月入住上饶市人民医院重症监护室(Intensive Care Unit,ICU)45例患者,超声监测患者剑突下及右侧腹腋中线图像,测量患者不同部位下随着不同呼吸周期时下腔静脉内径,并计算下腔静脉塌陷指数(inferior vena cava collapsibility index,IVC-CI),分析其是否具有统计学上的相关性。结果:本研究共45例患者同时获得剑突下及右侧腹腋中线图像;吸气末、呼气末右侧腹腋中线位置的下腔静脉内径值均显著高于剑突下位置的下腔静脉内径值,差异均有统计学意义(P<0.05);吸气末与呼气末下剑突下及右侧腹腋中线位置的下腔静脉长径、下腔静脉短径、IVC-CI比较差异均无统计学意义(P>0.05);吸气末与呼气末状态下,剑突下下腔静脉长径、下腔静脉短径、IVC-CI与右侧腹腋中线位置的下腔静脉长径、下腔静脉短径、IVC-CI均显著正相关(P<0.05)。结论:不同呼吸状态下,不同部位下腔静脉长径、下腔静脉短径、IVC-CI具有良好的相关性,可互相替代测量,值得临床重视。展开更多
Nickel-based superalloys are widely employed in modern aircraft engines because of their excellent material characteristics, particularly in the fabrication of film cooling holes. However, the high machining requireme...Nickel-based superalloys are widely employed in modern aircraft engines because of their excellent material characteristics, particularly in the fabrication of film cooling holes. However, the high machining requirement of a large number of film cooling holes can be extremely challenging. The hybrid machining technique of tube electrode high-speed electrochemical discharge drilling (TEHECDD) has been considered as a promising method for the production of film cooling holes. Compared with any single machining process, this hybrid technique requires the removal of more complex machining by-products, including debris produced in the electrical discharge machining process and hydroxide and bubbles generated in the electrochemical machining process. These by-products significantly affect the machining efficiency and surface quality of the machined products. In this study, tube electrodes in different inner diameters are designed and fabricated, and the effects of inner diameter on the machining efficiency and surface quality of TEHECDD are investigated. The results show that larger inner diameters could effectively improve the flushing condition and facilitate the removal of machining by-products. Therefore, higher material removal efficiency, surface quality, and electrode wear rate could be achieved by increasing the inner diameter of the tube electrode. (C) 2015 The Authors. Production and hosting by Elsevier Ltd. on behalf of Chinese Society of Aeronautics and Astronautics.展开更多
基金the financial support provided by the National Natural Science Foundation of China (No. 51475237)the National High-Tech Research and Development Program of China (No. 2013AA040101)+1 种基金the Program for New Century Excellent Talents in University (No. NCET-12-0627) of Chinathe Funding of Jiangsu Innovation Program for Graduate Education (No. KYLX_0232) of China
文摘Nickel-based superalloys are widely employed in modern aircraft engines because of their excellent material characteristics, particularly in the fabrication of film cooling holes. However, the high machining requirement of a large number of film cooling holes can be extremely challenging. The hybrid machining technique of tube electrode high-speed electrochemical discharge drilling (TEHECDD) has been considered as a promising method for the production of film cooling holes. Compared with any single machining process, this hybrid technique requires the removal of more complex machining by-products, including debris produced in the electrical discharge machining process and hydroxide and bubbles generated in the electrochemical machining process. These by-products significantly affect the machining efficiency and surface quality of the machined products. In this study, tube electrodes in different inner diameters are designed and fabricated, and the effects of inner diameter on the machining efficiency and surface quality of TEHECDD are investigated. The results show that larger inner diameters could effectively improve the flushing condition and facilitate the removal of machining by-products. Therefore, higher material removal efficiency, surface quality, and electrode wear rate could be achieved by increasing the inner diameter of the tube electrode. (C) 2015 The Authors. Production and hosting by Elsevier Ltd. on behalf of Chinese Society of Aeronautics and Astronautics.
