The vortex finder is essential in cyclone separators,significantly affecting separation performance via its diameter and insertion depth.The current study shows that as the insertion depth of the vortex finder increas...The vortex finder is essential in cyclone separators,significantly affecting separation performance via its diameter and insertion depth.The current study shows that as the insertion depth of the vortex finder increases,the separation efficiency initially increases and then decreases,and there exists a maximum point with which the corresponding insertion depth is the maximum efficiency insertion depth(SMEID).However,there are inconsistent conclusions in the existing literature regarding the maximum efficiency insertion depth and a lack of explanation for the flow field mechanism at the maximum efficiency insertion depth.This study examines the Stairmand type cyclone using 13μm silicon micro-powder,employing numerical simulation and cold mold experiments to explore the effects of the vortex finder's insertion depth and diameter on separation performance and flow field.The results indicate that the insertion depth has minimal impact on pressure drop.The maximum efficiency insertion depth of the vortex finder decreases as the diameter decreases and is independent of this insertion depth with respect to the inlet velocity.Analysis of the flow field reveals that the maximum efficiency insertion depth is essentially the result of a"competitive and synergistic"mechanism between the annular space separation capability and the separation space separation capability.展开更多
The correct method used in forest soil respiration measurement by Li-6400 is a premise of data quality control. According to the study in a larch plantation, collars should be inserted at 12 hours in advance to effici...The correct method used in forest soil respiration measurement by Li-6400 is a premise of data quality control. According to the study in a larch plantation, collars should be inserted at 12 hours in advance to efficiently reduce the influence of CO2 spring-out.Moreover, collar insertion depth substantially affected soil respiration measurement, i.e. when collar was shallowly inserted into soil,transversal gas diffusion and the CO2 re-spring-out caused by unstable collars in the measurement could lead to overestimating soil respiration rate; however, when collar was deeply inserted into soil, root respiration decline caused by root-cut and the most active respiratory of the surface soil separated by the inserted collars could lead to underestimating soil respiration rate. Furthermore, an error less than 5% could be guaranteed in typical sunny day if the target [CO2] was set to the mean value of ambient [CO2] in most time of the day, but it should be carefully set in early morning and late afternoon according to changing ambient [CO2]. This protocol of measurement is useful in real measurement.展开更多
Aiming at the conclusion that ＂there is no difference in efficacy between acupuncture and sham-acupuncture＂ in clinical research field of migraine in foreign countries in recent years, through the discussions on the...Aiming at the conclusion that ＂there is no difference in efficacy between acupuncture and sham-acupuncture＂ in clinical research field of migraine in foreign countries in recent years, through the discussions on the definition of sham acupuncture （placebo acupuncture）, the principles required to be obey in satisfactory placebo acupuncture, the definition, location, function as well as clinical results of shallow puncture, the authors probed into whether shallow puncture could be the control method of sham acupuncture （placebo acupuncture） in clinical research of acupuncture. It was demonstrated in the results that ＂acupuncture with minimal stimulation on skin superficial layer of meridian points or non-meridian points＂, the so-called control method of ＂sham acupuncture （placebo acupuncture）＂ excited holistic regulation of human body quite probably through ＂shallow puncture on cutaneous region of meridians＂ to achieve therapeutic effects. Hence, this method is not the appropriate control method of placebo acupuncture and cannot be the control method of sham acupuncture （placebo acupuncture） in clinical research of acupuncture. Therefore, it is naturally to repudiate the conclusion that ＂there is no difference in efficacy between acupuncture and sham acupuncture＂ in the research where this method is taken as the control of placebo acupuncture.展开更多
基金support from National Natural Science Foundation of China (grant Nos.21978322 and 21276274).
文摘The vortex finder is essential in cyclone separators,significantly affecting separation performance via its diameter and insertion depth.The current study shows that as the insertion depth of the vortex finder increases,the separation efficiency initially increases and then decreases,and there exists a maximum point with which the corresponding insertion depth is the maximum efficiency insertion depth(SMEID).However,there are inconsistent conclusions in the existing literature regarding the maximum efficiency insertion depth and a lack of explanation for the flow field mechanism at the maximum efficiency insertion depth.This study examines the Stairmand type cyclone using 13μm silicon micro-powder,employing numerical simulation and cold mold experiments to explore the effects of the vortex finder's insertion depth and diameter on separation performance and flow field.The results indicate that the insertion depth has minimal impact on pressure drop.The maximum efficiency insertion depth of the vortex finder decreases as the diameter decreases and is independent of this insertion depth with respect to the inlet velocity.Analysis of the flow field reveals that the maximum efficiency insertion depth is essentially the result of a"competitive and synergistic"mechanism between the annular space separation capability and the separation space separation capability.
基金National Natural Science Foundation of China (30300271),Program of Key Basic Research from Ministry of Science and Technology (2004CCA02700) and Sina-Japan cooperation project on larch forest study.
文摘The correct method used in forest soil respiration measurement by Li-6400 is a premise of data quality control. According to the study in a larch plantation, collars should be inserted at 12 hours in advance to efficiently reduce the influence of CO2 spring-out.Moreover, collar insertion depth substantially affected soil respiration measurement, i.e. when collar was shallowly inserted into soil,transversal gas diffusion and the CO2 re-spring-out caused by unstable collars in the measurement could lead to overestimating soil respiration rate; however, when collar was deeply inserted into soil, root respiration decline caused by root-cut and the most active respiratory of the surface soil separated by the inserted collars could lead to underestimating soil respiration rate. Furthermore, an error less than 5% could be guaranteed in typical sunny day if the target [CO2] was set to the mean value of ambient [CO2] in most time of the day, but it should be carefully set in early morning and late afternoon according to changing ambient [CO2]. This protocol of measurement is useful in real measurement.
基金Academy-rank research project of China Academy of Chinese Medical Sciences:ZZ 2006084
文摘Aiming at the conclusion that ＂there is no difference in efficacy between acupuncture and sham-acupuncture＂ in clinical research field of migraine in foreign countries in recent years, through the discussions on the definition of sham acupuncture （placebo acupuncture）, the principles required to be obey in satisfactory placebo acupuncture, the definition, location, function as well as clinical results of shallow puncture, the authors probed into whether shallow puncture could be the control method of sham acupuncture （placebo acupuncture） in clinical research of acupuncture. It was demonstrated in the results that ＂acupuncture with minimal stimulation on skin superficial layer of meridian points or non-meridian points＂, the so-called control method of ＂sham acupuncture （placebo acupuncture）＂ excited holistic regulation of human body quite probably through ＂shallow puncture on cutaneous region of meridians＂ to achieve therapeutic effects. Hence, this method is not the appropriate control method of placebo acupuncture and cannot be the control method of sham acupuncture （placebo acupuncture） in clinical research of acupuncture. Therefore, it is naturally to repudiate the conclusion that ＂there is no difference in efficacy between acupuncture and sham acupuncture＂ in the research where this method is taken as the control of placebo acupuncture.
