This study represents the influence on exhaust performance by active muffler valve spring.The main experimental parameters were engine speeds and torsion coil spring constants in the active muffler.When the muffler va...This study represents the influence on exhaust performance by active muffler valve spring.The main experimental parameters were engine speeds and torsion coil spring constants in the active muffler.When the muffler valve spring has a low spring constant of k=0.75,the sound pressure level was low at the region of engine speed 2000 to 2500 r/min,and the velocity of exhaust gas was high at spring constant k=0.75.When the engine speed was under 1500 r/min,the mean concentration of CO was high in case without muffler valve.When the engine speed in the range of 1600 to 2600 r/min with spring constant k=0.75,the mean HC concentration showed the lowest value.Without muffler valve,the temperature in the muffler was higher than the case with muffler valve.This research represented that the performance of the active muffler valve spring constant k=0.75 was higher than that without muffler valve and valve spring constant k=0.70.Among the three cases of experimental condition,with a spring constant k=0.75,0.70 and without muffler valve,the exhaust performance was high in case active muffler valve spring constant k=0.70.展开更多
Forced dissociation of selectin-ligand bonds is crucial to such biological processes as leukocyte recruitment, thrombosis formation, as well as tumor metastasis. While
This article discussed how to improve constant force performance of the large capacity constant spring support hangers. Large deviations have been found between product testing results and theoretical calculations aft...This article discussed how to improve constant force performance of the large capacity constant spring support hangers. Large deviations have been found between product testing results and theoretical calculations after years of research and testing. The deviations mainly are caused by internal frictions inside the constant spring support hangers. By reducing or properly using internal frictions, consistent results between testing and theoretical calculation have been achieved. Based on product performance testing results recently, constant force performance of hangers has been improved greatly by adopting new methodology.展开更多
原子力显微镜(atomic force microscopy,AFM)在微纳米尺度力学测量领域有着广泛应用,其微悬臂梁探针的弹性常数是直接影响测量结果准确性的关键因素之一。弯曲法是标定微悬臂梁弹性常数的一类重要方法,基于弯曲标定原理提出了一种新的...原子力显微镜(atomic force microscopy,AFM)在微纳米尺度力学测量领域有着广泛应用,其微悬臂梁探针的弹性常数是直接影响测量结果准确性的关键因素之一。弯曲法是标定微悬臂梁弹性常数的一类重要方法,基于弯曲标定原理提出了一种新的技术实现方案,并研制了相应的标定系统。借助精密运动定位台使微悬臂梁接触超精密天平并产生弯曲,分别以天平和光杠杆机构同步测得接触力和梁的弯曲量,再根据胡克定律直接算得弹性常数。利用所研制的系统对多种型号的微悬臂梁进行了标定,实验结果表明该系统具有良好的准确性和重复性,测量相对标准差小于5%。展开更多
基金This work was supported by the Brain Korea 21 Projects,and the authors gratefully appreciate the support.
文摘This study represents the influence on exhaust performance by active muffler valve spring.The main experimental parameters were engine speeds and torsion coil spring constants in the active muffler.When the muffler valve spring has a low spring constant of k=0.75,the sound pressure level was low at the region of engine speed 2000 to 2500 r/min,and the velocity of exhaust gas was high at spring constant k=0.75.When the engine speed was under 1500 r/min,the mean concentration of CO was high in case without muffler valve.When the engine speed in the range of 1600 to 2600 r/min with spring constant k=0.75,the mean HC concentration showed the lowest value.Without muffler valve,the temperature in the muffler was higher than the case with muffler valve.This research represented that the performance of the active muffler valve spring constant k=0.75 was higher than that without muffler valve and valve spring constant k=0.70.Among the three cases of experimental condition,with a spring constant k=0.75,0.70 and without muffler valve,the exhaust performance was high in case active muffler valve spring constant k=0.70.
基金Supported by National Natural Science Foundation of China grants 30730032 and 10702075National Key Basic Research Foundation of China grant 2006CB910303+1 种基金National High Technology Research and Development Program of China grant 2007AA02Z306Chinese Academy of Sciences grant KJCX2-YW-L08
文摘Forced dissociation of selectin-ligand bonds is crucial to such biological processes as leukocyte recruitment, thrombosis formation, as well as tumor metastasis. While
文摘This article discussed how to improve constant force performance of the large capacity constant spring support hangers. Large deviations have been found between product testing results and theoretical calculations after years of research and testing. The deviations mainly are caused by internal frictions inside the constant spring support hangers. By reducing or properly using internal frictions, consistent results between testing and theoretical calculation have been achieved. Based on product performance testing results recently, constant force performance of hangers has been improved greatly by adopting new methodology.
文摘原子力显微镜(atomic force microscopy,AFM)在微纳米尺度力学测量领域有着广泛应用,其微悬臂梁探针的弹性常数是直接影响测量结果准确性的关键因素之一。弯曲法是标定微悬臂梁弹性常数的一类重要方法,基于弯曲标定原理提出了一种新的技术实现方案,并研制了相应的标定系统。借助精密运动定位台使微悬臂梁接触超精密天平并产生弯曲,分别以天平和光杠杆机构同步测得接触力和梁的弯曲量,再根据胡克定律直接算得弹性常数。利用所研制的系统对多种型号的微悬臂梁进行了标定,实验结果表明该系统具有良好的准确性和重复性,测量相对标准差小于5%。
