Mechanics effect of laser thermal stress is a new manufacturing technology, which uses thermal stress by high power laser acted on the surface of metal material to produce stress field. The technologies such as sheet ...Mechanics effect of laser thermal stress is a new manufacturing technology, which uses thermal stress by high power laser acted on the surface of metal material to produce stress field. The technologies such as sheet metal formation by laser thermal stress, measurement by laser scratching and measurement by XRD (X-ray diffraction) are formed based on mechanics effects of laser thermal stress. The mechanisms of sheet metal formation by laser thermal stress, measurement by laser scratching and measurement by XRD are analyzed, and the theory of photo-mechanics manufacturing and detecting technologies based on laser thermal stress is originally put forward, whose experiment is primitively researched, and the manufacturing theory by mechanics effects of laser thermal stress is established.展开更多
Based on the quark-gluon contents of nucleon and strongly believing that the force mediators,Pomeronand its counterpart in the conventional approach of Regge theory,for high energy diffractive process would be the ten...Based on the quark-gluon contents of nucleon and strongly believing that the force mediators,Pomeronand its counterpart in the conventional approach of Regge theory,for high energy diffractive process would be the tensorglueball and Odderon respectively,we discuss photo-production of vector meson φ off the deuteron at energy less than 3GeV in the QCD inspired model in which the quark gluon degrees of freedom and glueball,Odderon exchange are takeninto account.A calculation is performed for γ + D →φ + D,and the theoretical predictions of the differential crosssection dσ^(γD)) /dt,are presented and compared with available experimental data.Our QCD inspired model reproducesdata quite well in the whole range of the experimental measurements up to |t| ■0.4 GeV.Our results can be used toextract γn→φn data,which cannot be measured in experiment.展开更多
This paper presents an experimental investigation of effects of a kind of streamwise-grooved blade on the performance of an axial-flow fan. The flow field at 25% chord downstream from the trailing edge at hub was meas...This paper presents an experimental investigation of effects of a kind of streamwise-grooved blade on the performance of an axial-flow fan. The flow field at 25% chord downstream from the trailing edge at hub was measured using a 5-hole pressure probe at different mass-flow conditions. The fan performance of the groove blades was compared with that of the smooth blades. The measurement results indicate that： （ 1 ） the non-smooth blades increase mass flow of the fan at the same throttle conditions except a near stall condition; （2） the non-smooth blades reduce the relative total pressure loss in the rotor passage and increase the fan＇s total pressure rise at the test mass-flow conditions except the near stall condition; （3） Negative benefits are obtained at a near stall condition when the smooth blades are replaced by the non-smooth ones. The fan mass flow decreases 0.9% while the total-pressure rise decreases 2.4% at the near stall condition.展开更多
Many studies have shown that either the nearby astrophysical source or dark matter （DM） annihilation/decay can be used to explain the excess of high energy cosmic ray （CR） e^±which is detected by many experim...Many studies have shown that either the nearby astrophysical source or dark matter （DM） annihilation/decay can be used to explain the excess of high energy cosmic ray （CR） e^±which is detected by many experiments, such as PAMELA and AMS-02. Recently, the dark matter particle explorer （DAMPE） collaboration has reported its first result of the total CR e^± spectrum from 25 GeV to 4.6TeV with high precision. In this work, we study the DM annihilation and pulsar interpretations of this result. We show that the leptonic DM annihilation channels to r＋＇/＂-, 4p, 4＂/＇, and mixed charged lepton final states can well explain the DAMPE e^± spectrum. We also find that the mixed charged leptons channel would lead to a sharp drop structure at - TeV. However, the ordinary DM explanations have been almost excluded by the constraints from the observations of gamma-ray and CMB, unless some exotic DM models are introduced. In the pulsar scenario, we analyze 21 nearby known pulsars and assume that one of them dominantly contributes to the high energy CR e^± spectrum. Involving the constraint from the Fermi-LAT observation of the e^± anisotropy, we find that two pulsars could explain the DAMPE e^± spectrum. Our results show that it is difficult to discriminate between the DM annihilation and single pulsar explanations of high energy e^± with the current DAMPE result.展开更多
基金this research from the Scientific Research Fund of Jiangsu Polytechnic University(GrantNo.ZMF07020042)Fund of Jiangsu ProvincialKey Laboratory for Science and Technology of Photo-manufacroring (Grant No.GZ-1-02)the NaturalScience Foundation of the Jiangsu Higher EducationInstitutions of China( Grant No. 08KJB430002 ) is gratefully acknowledged.
文摘Mechanics effect of laser thermal stress is a new manufacturing technology, which uses thermal stress by high power laser acted on the surface of metal material to produce stress field. The technologies such as sheet metal formation by laser thermal stress, measurement by laser scratching and measurement by XRD (X-ray diffraction) are formed based on mechanics effects of laser thermal stress. The mechanisms of sheet metal formation by laser thermal stress, measurement by laser scratching and measurement by XRD are analyzed, and the theory of photo-mechanics manufacturing and detecting technologies based on laser thermal stress is originally put forward, whose experiment is primitively researched, and the manufacturing theory by mechanics effects of laser thermal stress is established.
基金Supported by National Natural Science Foundation of China under Grant Nos.10647002 and 10565001
文摘Based on the quark-gluon contents of nucleon and strongly believing that the force mediators,Pomeronand its counterpart in the conventional approach of Regge theory,for high energy diffractive process would be the tensorglueball and Odderon respectively,we discuss photo-production of vector meson φ off the deuteron at energy less than 3GeV in the QCD inspired model in which the quark gluon degrees of freedom and glueball,Odderon exchange are takeninto account.A calculation is performed for γ + D →φ + D,and the theoretical predictions of the differential crosssection dσ^(γD)) /dt,are presented and compared with available experimental data.Our QCD inspired model reproducesdata quite well in the whole range of the experimental measurements up to |t| ■0.4 GeV.Our results can be used toextract γn→φn data,which cannot be measured in experiment.
基金The authors would like to acknowledge National Natural Science Foundation of China for the support projects Grant No.50376002.
文摘This paper presents an experimental investigation of effects of a kind of streamwise-grooved blade on the performance of an axial-flow fan. The flow field at 25% chord downstream from the trailing edge at hub was measured using a 5-hole pressure probe at different mass-flow conditions. The fan performance of the groove blades was compared with that of the smooth blades. The measurement results indicate that： （ 1 ） the non-smooth blades increase mass flow of the fan at the same throttle conditions except a near stall condition; （2） the non-smooth blades reduce the relative total pressure loss in the rotor passage and increase the fan＇s total pressure rise at the test mass-flow conditions except the near stall condition; （3） Negative benefits are obtained at a near stall condition when the smooth blades are replaced by the non-smooth ones. The fan mass flow decreases 0.9% while the total-pressure rise decreases 2.4% at the near stall condition.
基金supported by the National Key Program for Research and Development(Grant No.2016YFA0400200)the National Natural Science Foundation of China(Grant Nos.U1738209,11475189,and 11475191)
文摘Many studies have shown that either the nearby astrophysical source or dark matter （DM） annihilation/decay can be used to explain the excess of high energy cosmic ray （CR） e^±which is detected by many experiments, such as PAMELA and AMS-02. Recently, the dark matter particle explorer （DAMPE） collaboration has reported its first result of the total CR e^± spectrum from 25 GeV to 4.6TeV with high precision. In this work, we study the DM annihilation and pulsar interpretations of this result. We show that the leptonic DM annihilation channels to r＋＇/＂-, 4p, 4＂/＇, and mixed charged lepton final states can well explain the DAMPE e^± spectrum. We also find that the mixed charged leptons channel would lead to a sharp drop structure at - TeV. However, the ordinary DM explanations have been almost excluded by the constraints from the observations of gamma-ray and CMB, unless some exotic DM models are introduced. In the pulsar scenario, we analyze 21 nearby known pulsars and assume that one of them dominantly contributes to the high energy CR e^± spectrum. Involving the constraint from the Fermi-LAT observation of the e^± anisotropy, we find that two pulsars could explain the DAMPE e^± spectrum. Our results show that it is difficult to discriminate between the DM annihilation and single pulsar explanations of high energy e^± with the current DAMPE result.
