[Objective] The research aimed to study the meso-scale characteristics of a hail process in Linyi area. [Method] By comprehensively using MICAPS conventional observation data, automatic encryption ground station, MM5 ...[Objective] The research aimed to study the meso-scale characteristics of a hail process in Linyi area. [Method] By comprehensively using MICAPS conventional observation data, automatic encryption ground station, MM5 model product and Doppler weather radar data, a strong convective hail weather process which happened in Shandong Peninsula and southeast of Shandong on May 30, 2010 was analyzed. The circulation background and physical mechanism of strong convection weather occurrence, the features of meso- and micro-scale systems were discussed. Some occurrence and development rules of such weather were found. [Result] The strong convective weather was mainly affected by the cold vortex and translot. The high-altitude northwest airflow, low-level southwest airflow, dry and cold air at the high layer, warm and wet air at the low layer, forward-tilting trough caused the strong convective weather. The radar echo analysis showed that the radar echo in the process belonged to the typical multi-monomer windstorm echo, and the strong echo zone was in the forefront of echo. When the convection development was the strongest, the echo intensity reached 65 dBz, and the echo top height surpassed 11 km. As the development of windstorm monomer, the big-value zone of vertical liquid water content product had the jumping formation and disappearance. Moreover, there was obvious weak echo zone. The windstorm monomer moved to the southeast direction as the precipitation system. In the right front of monomer moving direction, there was hook echo feature. The evolution characteristics of radial speed field at the different elevation angles before and after the hail weather occurrence were analyzed. It was found that the radial speed field had some premonitory variations before the hail weather occurrence. Doppler radar product was used to improve the initial field of MM5 model, which could improve the forecast effect in the certain degree and the accuracy of short-time forecast and nowcasting. [Conclusion] The research accumulated the experience for the short-term forecast and nowcasting work of strong convective weather in future.展开更多
High-speed steel W18Cr4V is commonly used in industries such as blade and mould manufacturers because of its high level of hardness and toughness, red-hardness and resistance. Ion implantation is an effective method t...High-speed steel W18Cr4V is commonly used in industries such as blade and mould manufacturers because of its high level of hardness and toughness, red-hardness and resistance. Ion implantation is an effective method to improve the wear resistance of W18Cr4V. In our investigation, Ta and Ta+N ion implantation was performed on W18Cr4V high-speed steel. The surface properties after implantation were evaluated by measuring friction coefficients while the carbonyl phase of the surface was analyzed by X-ray diffraction analysis. It was found that the friction coefficients of the treated samples were much lower. Samples implanted with Ta+N had a lower friction coefficients than samples implanted only with Ta. This can be attributed to the formation of a new chemical compound, Fe7Ta3, on both surfaces. An even harder chemical compound, Fe2N, was formed on both surfaces of Ta+N implanted samples.展开更多
[Objective] The aim was to discuss dynamic conditions for one rare regional rainstorm. [Method] By using conventional material, ground encryption automatic station materials, wind profiling radar data and Doppler rada...[Objective] The aim was to discuss dynamic conditions for one rare regional rainstorm. [Method] By using conventional material, ground encryption automatic station materials, wind profiling radar data and Doppler radar data, strong precipitation and regional large rainstorm in Lingxi area on August 3, 2010, were expounded principal of heavy weather analysis. [Result] The precipitation process was the result of different scales and different height systems influenced by the southwest airflow in the edge of subtropical high, weak cold air penetrating southward before westerly trough and the easterly in the higher layer (10 km above); the instability of atmosphere structure was the premise of strong precipitation. Ground convergent, east storm with senior northwestern current interaction triggered the release of unstable energy; the southwest airstream in the edge of subtropical high provided water vapor supply. The duration of the precipitation was short and the intensity was large. Precipitation moved to certain direction, having typical mesoscale strong convection system. Strong precipitation fell in the same place as the convergence area of wind field. The place having next strong precipitation can be predicted based on the wind field convergence position along with the movement of time. Outline radar data and Doppler radar data contour line products can more accurately represent atmospheric vertical wind field structure. [Conclusion] The study provided certain references for the report of rainstorm.展开更多
文摘[Objective] The research aimed to study the meso-scale characteristics of a hail process in Linyi area. [Method] By comprehensively using MICAPS conventional observation data, automatic encryption ground station, MM5 model product and Doppler weather radar data, a strong convective hail weather process which happened in Shandong Peninsula and southeast of Shandong on May 30, 2010 was analyzed. The circulation background and physical mechanism of strong convection weather occurrence, the features of meso- and micro-scale systems were discussed. Some occurrence and development rules of such weather were found. [Result] The strong convective weather was mainly affected by the cold vortex and translot. The high-altitude northwest airflow, low-level southwest airflow, dry and cold air at the high layer, warm and wet air at the low layer, forward-tilting trough caused the strong convective weather. The radar echo analysis showed that the radar echo in the process belonged to the typical multi-monomer windstorm echo, and the strong echo zone was in the forefront of echo. When the convection development was the strongest, the echo intensity reached 65 dBz, and the echo top height surpassed 11 km. As the development of windstorm monomer, the big-value zone of vertical liquid water content product had the jumping formation and disappearance. Moreover, there was obvious weak echo zone. The windstorm monomer moved to the southeast direction as the precipitation system. In the right front of monomer moving direction, there was hook echo feature. The evolution characteristics of radial speed field at the different elevation angles before and after the hail weather occurrence were analyzed. It was found that the radial speed field had some premonitory variations before the hail weather occurrence. Doppler radar product was used to improve the initial field of MM5 model, which could improve the forecast effect in the certain degree and the accuracy of short-time forecast and nowcasting. [Conclusion] The research accumulated the experience for the short-term forecast and nowcasting work of strong convective weather in future.
文摘High-speed steel W18Cr4V is commonly used in industries such as blade and mould manufacturers because of its high level of hardness and toughness, red-hardness and resistance. Ion implantation is an effective method to improve the wear resistance of W18Cr4V. In our investigation, Ta and Ta+N ion implantation was performed on W18Cr4V high-speed steel. The surface properties after implantation were evaluated by measuring friction coefficients while the carbonyl phase of the surface was analyzed by X-ray diffraction analysis. It was found that the friction coefficients of the treated samples were much lower. Samples implanted with Ta+N had a lower friction coefficients than samples implanted only with Ta. This can be attributed to the formation of a new chemical compound, Fe7Ta3, on both surfaces. An even harder chemical compound, Fe2N, was formed on both surfaces of Ta+N implanted samples.
文摘[Objective] The aim was to discuss dynamic conditions for one rare regional rainstorm. [Method] By using conventional material, ground encryption automatic station materials, wind profiling radar data and Doppler radar data, strong precipitation and regional large rainstorm in Lingxi area on August 3, 2010, were expounded principal of heavy weather analysis. [Result] The precipitation process was the result of different scales and different height systems influenced by the southwest airflow in the edge of subtropical high, weak cold air penetrating southward before westerly trough and the easterly in the higher layer (10 km above); the instability of atmosphere structure was the premise of strong precipitation. Ground convergent, east storm with senior northwestern current interaction triggered the release of unstable energy; the southwest airstream in the edge of subtropical high provided water vapor supply. The duration of the precipitation was short and the intensity was large. Precipitation moved to certain direction, having typical mesoscale strong convection system. Strong precipitation fell in the same place as the convergence area of wind field. The place having next strong precipitation can be predicted based on the wind field convergence position along with the movement of time. Outline radar data and Doppler radar data contour line products can more accurately represent atmospheric vertical wind field structure. [Conclusion] The study provided certain references for the report of rainstorm.
