期刊文献+
共找到2篇文章
< 1 >
每页显示 20 50 100
柴油机喷油嘴是喷油系统与燃烧室之间的关键接口 被引量:4
1
作者 D.potz W.CHRIST +1 位作者 B.DITTUS 陈卫群 《现代车用动力》 2004年第4期11-15,32,共6页
目前市场上有 3种不同的基本型燃油喷射系统 ,因此 ,必须针对不同的系统要求设计不同的喷油嘴。正因为如此 ,喷油嘴用途不同 ,其最高压力、有害容积以及摩擦分析的评定标准也不同。现在和未来的排放法规要求进一步大力改进柴油机喷油嘴... 目前市场上有 3种不同的基本型燃油喷射系统 ,因此 ,必须针对不同的系统要求设计不同的喷油嘴。正因为如此 ,喷油嘴用途不同 ,其最高压力、有害容积以及摩擦分析的评定标准也不同。现在和未来的排放法规要求进一步大力改进柴油机喷油嘴的座面和喷雾形状。采取适当措施 ,在几何形状、内部油道和喷雾形态之间作些改动可以使柴油机的性能得到改善。作为针阀体的精确几何特征 ,喷孔决定喷雾特征进而对柴油机的排放带来影响。喷油嘴的喷雾特征主要受喷孔微小形状的影响。通过喷孔的各项参数 (直径、长度、进油边缘形状、微观表面 )配合得到理想的燃油流动特性才能满足柴油机对喷雾的要求。作为针阀的精确几何尺寸 ,密封座面决定了喷油嘴的偏移特性和变化量。普通喷油嘴的密封线在工作期内会慢慢移向针阀顶端。相反 ,允许降低公差范围但要求完善的磨削和测量技术的新型喷油嘴ZHI和IRH的密封线却慢慢远离针阀顶端。密封线在规定寿命期内的这种移动 ,可以弥补喷油器零件或针阀体部件所造成的负面作用。即使在部分针阀升程的条件下 ,喷油嘴也必须确保每个喷孔的供油量一致。 展开更多
关键词 柴油机喷油嘴 喷油系统 燃烧室 接口
下载PDF
Surgical palliation of gastric outlet obstruction in advanced malignancy 被引量:2
2
作者 Brittany A potz Thomas J Miner 《World Journal of Gastrointestinal Surgery》 SCIE CAS 2016年第8期545-555,共11页
Gastric outlet obstruction(GOO) is a common problem associated with advanced malignancies of the upper gastrointestinal tract.Palliative treatment of patients' symptoms who present with GOO is an important aspect ... Gastric outlet obstruction(GOO) is a common problem associated with advanced malignancies of the upper gastrointestinal tract.Palliative treatment of patients' symptoms who present with GOO is an important aspect of their care.Surgical palliation of malignancy is defined as a procedure performed with the intention of relieving symptoms caused by an advanced malignancy or improving quality of life.Palliative treatment for GOO includes operative(open and laparoscopic gastrojejunostomy) and non-operative(endoscopic stenting) options.The performance status and medical condition of the patient,the extent of the cancer,the patients prognosis,the availability of a curative procedure,the natural history of symptoms of the disease(primary and secondary),the durability of the procedure,and the quality of life and life expectancy of the patient should always be considered when choosing treatment for any patient with advanced malignancy.Gastrojejunostomy appears to be associated with better long term symptom relief while stenting appears to be associated with lower immediate procedure related morbidity. 展开更多
关键词 SURGICAL PALLIATION Gastric outlet obstruction ADVANCED MALIGNANCY GASTROJEJUNOSTOMY Endoscopic STENTING
下载PDF
上一页 1 下一页 到第
使用帮助 返回顶部