Immature stages of 3 species of the tribe Ozophorini from China are described for the first time, they are Bryanellocoris orientalis Hidaka (3rd^5th instars), Primierus longispinus Zheng (4th^5th instars) and Vertoman...Immature stages of 3 species of the tribe Ozophorini from China are described for the first time, they are Bryanellocoris orientalis Hidaka (3rd^5th instars), Primierus longispinus Zheng (4th^5th instars) and Vertomannus brevicollum Zheng (4th^5th instars). Abrief study on fine structure of pale spots on head, pronotum and abdomen of 5th instar nymph of Bryanellocoris orientalis Hidaka was also given.展开更多
The effects of different yaw angles on the aerodynamic performance of city electric multiple units(EMUs)were investigated in a wind tunnel using a 1:16.8 scaled model.Pressure scanning valve and six-component box-type...The effects of different yaw angles on the aerodynamic performance of city electric multiple units(EMUs)were investigated in a wind tunnel using a 1:16.8 scaled model.Pressure scanning valve and six-component box-type aerodynamic balance were used to test the pressure distribution and aerodynamic force of the head car respectively from the 1.5-and 3-coach grouping city EMU models.Meanwhile,the effects of the yaw angles on the pressure distribution of the streamlined head as well as the aerodynamic forces of the train were analyzed.The experimental results showed that the pressure coefficient was the smallest at the maximum slope of the main shape-line.The side force coefficient and pressure coefficient along the head car cross-section were most affected by crosswind when the yaw angle was 55°,and replacing a 3-coach grouping with a 1.5-coach grouping had obvious advantages for wind tunnel testing when the yaw angle was within 24.2°.In addition,the relative errors of lift coefficient C_(L),roll moment coefficient C_(Mx),side force coefficient C_(S),and drag coefficient C_(D) between the 1.5-and 3-coach cases were below 5.95%,which all met the requirements of the experimental accuracy.展开更多
We have investigated the doping behavior of rare earth element holmium （Ho3＋） in ZnO semiconductor. The structural, microstructure, and magnetic properties of Zn1-xHoxO （x=0.0, 0.04, and 0.05） thin films deposite...We have investigated the doping behavior of rare earth element holmium （Ho3＋） in ZnO semiconductor. The structural, microstructure, and magnetic properties of Zn1-xHoxO （x=0.0, 0.04, and 0.05） thin films deposited on Si（100） substrate by thermal evaporation technique were studied. The ceramic targets were prepared by conventional solid state ceramic technique. The pallets used as target were final sintered at 900℃ in the presence of N2 atmosphere. The experimental results of X-ray diffraction （XRD） spectra, surface morphology, and magnetic properties show that the Ho3＋ doped ZnO thin films has a strong influence on the materials properties. The higher angle shift in peak position and most preferred （101） orientation were observed in XRD pattern. These spectra confirmed the substitution of Ho3＋ in ZnO lattice. The surface morphology and stoichiometry for both bulk and thin films were analyzed by scanning electron microscopy and energy dispersive spectroscopy. It was observed that grain size decreases with the increase of Ho3＋. Room temperature ferromagnetism was observed for Zn0.95Ho0.050 films. The ferromagnetism might be attributed to the substitution of Ho ions for Zn2＋ in ZnO lattices.展开更多
基金The project was supported by "Education Grant" of National Natural SciencesFoundation of China (No. 108)
文摘Immature stages of 3 species of the tribe Ozophorini from China are described for the first time, they are Bryanellocoris orientalis Hidaka (3rd^5th instars), Primierus longispinus Zheng (4th^5th instars) and Vertomannus brevicollum Zheng (4th^5th instars). Abrief study on fine structure of pale spots on head, pronotum and abdomen of 5th instar nymph of Bryanellocoris orientalis Hidaka was also given.
基金Project(2020YFA0710903) supported by the National Key R&D Program of ChinaProjects(2020zzts111, 2020zzts117)supported by the Graduate Student Independent Innovation Project of Central South University,ChinaProject(202037)supported by Transport Department of Hunan Province Technology Innovation Project,China。
文摘The effects of different yaw angles on the aerodynamic performance of city electric multiple units(EMUs)were investigated in a wind tunnel using a 1:16.8 scaled model.Pressure scanning valve and six-component box-type aerodynamic balance were used to test the pressure distribution and aerodynamic force of the head car respectively from the 1.5-and 3-coach grouping city EMU models.Meanwhile,the effects of the yaw angles on the pressure distribution of the streamlined head as well as the aerodynamic forces of the train were analyzed.The experimental results showed that the pressure coefficient was the smallest at the maximum slope of the main shape-line.The side force coefficient and pressure coefficient along the head car cross-section were most affected by crosswind when the yaw angle was 55°,and replacing a 3-coach grouping with a 1.5-coach grouping had obvious advantages for wind tunnel testing when the yaw angle was within 24.2°.In addition,the relative errors of lift coefficient C_(L),roll moment coefficient C_(Mx),side force coefficient C_(S),and drag coefficient C_(D) between the 1.5-and 3-coach cases were below 5.95%,which all met the requirements of the experimental accuracy.
文摘We have investigated the doping behavior of rare earth element holmium （Ho3＋） in ZnO semiconductor. The structural, microstructure, and magnetic properties of Zn1-xHoxO （x=0.0, 0.04, and 0.05） thin films deposited on Si（100） substrate by thermal evaporation technique were studied. The ceramic targets were prepared by conventional solid state ceramic technique. The pallets used as target were final sintered at 900℃ in the presence of N2 atmosphere. The experimental results of X-ray diffraction （XRD） spectra, surface morphology, and magnetic properties show that the Ho3＋ doped ZnO thin films has a strong influence on the materials properties. The higher angle shift in peak position and most preferred （101） orientation were observed in XRD pattern. These spectra confirmed the substitution of Ho3＋ in ZnO lattice. The surface morphology and stoichiometry for both bulk and thin films were analyzed by scanning electron microscopy and energy dispersive spectroscopy. It was observed that grain size decreases with the increase of Ho3＋. Room temperature ferromagnetism was observed for Zn0.95Ho0.050 films. The ferromagnetism might be attributed to the substitution of Ho ions for Zn2＋ in ZnO lattices.
