The waveform of the explosion shock wave under free-field air explosion is an extremely complex problem.It is generally considered that the waveform consists of overpressure peak,positive pressure zone and negative pr...The waveform of the explosion shock wave under free-field air explosion is an extremely complex problem.It is generally considered that the waveform consists of overpressure peak,positive pressure zone and negative pressure zone.Most of current practice usually considers only the positive pressure.Many empirical relations are available to predict overpressure peak,the positive pressure action time and pressure decay law.However,there are few models that can predict the whole waveform.The whole process of explosion shock wave overpressure,which was expressed as the product of the three factor functions of peak,attenuation and oscillation,was proposed in the present work.According to the principle of explosion similarity,the scaled parameters were introduced and the empirical formula was absorbed to form a mathematical model of shock wave overpressure.Parametric numerical simulations of free-field air explosions were conducted.By experimental verification of the AUTODYN numerical method and comparing the analytical and simulated curves,the model is proved to be accurate to calculate the shock wave overpressure under free-field air explosion.In addition,through the model the shock wave overpressure at different time and distance can be displayed in three dimensions.The model makes the time needed for theoretical calculation much less than that for numerical simulation.展开更多
为探究脱病毒种苗对果蔗的影响,本研究以广东黄皮果蔗为试验材料,进行了自留种、脱毒一代、脱毒二代果蔗种苗的田间性状和果汁品质的比较研究。结果表明,3种材料中,脱毒二代果蔗的田间生长状态最佳,与自留种和脱毒一代相比,其地上株高...为探究脱病毒种苗对果蔗的影响,本研究以广东黄皮果蔗为试验材料,进行了自留种、脱毒一代、脱毒二代果蔗种苗的田间性状和果汁品质的比较研究。结果表明,3种材料中,脱毒二代果蔗的田间生长状态最佳,与自留种和脱毒一代相比,其地上株高分别提高9.08%、5.80%(其中可食部分高度分别提高13.64%、7.19%),茎粗分别提高13.98%、9.71%,产量分别提高47.76%、63.72%(达到159.5 t hm^(-2)),出汁率分别提高3.64%、9.17%,蔗汁的总糖含量分别下降10.14%、12.73%;脱毒对果蔗蔗汁的密度、锤度和纤维含量无显著影响;脱毒苗第一代果蔗与自留种的产量和蔗汁品质无显著差异,脱毒组培苗作为第一代种苗可用于繁育脱毒果蔗种茎,3—4月份适宜移栽。因此,相对于一代组培苗,采用脱毒第二代种苗(脱毒第一代种苗种植收获的果蔗种茎)进行商品蔗种植效果更好,可促进果蔗田间生长,显著提高果蔗的产量。展开更多
基金partially sponsored by Foundation of PLA Rocket Force
文摘The waveform of the explosion shock wave under free-field air explosion is an extremely complex problem.It is generally considered that the waveform consists of overpressure peak,positive pressure zone and negative pressure zone.Most of current practice usually considers only the positive pressure.Many empirical relations are available to predict overpressure peak,the positive pressure action time and pressure decay law.However,there are few models that can predict the whole waveform.The whole process of explosion shock wave overpressure,which was expressed as the product of the three factor functions of peak,attenuation and oscillation,was proposed in the present work.According to the principle of explosion similarity,the scaled parameters were introduced and the empirical formula was absorbed to form a mathematical model of shock wave overpressure.Parametric numerical simulations of free-field air explosions were conducted.By experimental verification of the AUTODYN numerical method and comparing the analytical and simulated curves,the model is proved to be accurate to calculate the shock wave overpressure under free-field air explosion.In addition,through the model the shock wave overpressure at different time and distance can be displayed in three dimensions.The model makes the time needed for theoretical calculation much less than that for numerical simulation.
文摘为探究脱病毒种苗对果蔗的影响,本研究以广东黄皮果蔗为试验材料,进行了自留种、脱毒一代、脱毒二代果蔗种苗的田间性状和果汁品质的比较研究。结果表明,3种材料中,脱毒二代果蔗的田间生长状态最佳,与自留种和脱毒一代相比,其地上株高分别提高9.08%、5.80%(其中可食部分高度分别提高13.64%、7.19%),茎粗分别提高13.98%、9.71%,产量分别提高47.76%、63.72%(达到159.5 t hm^(-2)),出汁率分别提高3.64%、9.17%,蔗汁的总糖含量分别下降10.14%、12.73%;脱毒对果蔗蔗汁的密度、锤度和纤维含量无显著影响;脱毒苗第一代果蔗与自留种的产量和蔗汁品质无显著差异,脱毒组培苗作为第一代种苗可用于繁育脱毒果蔗种茎,3—4月份适宜移栽。因此,相对于一代组培苗,采用脱毒第二代种苗(脱毒第一代种苗种植收获的果蔗种茎)进行商品蔗种植效果更好,可促进果蔗田间生长,显著提高果蔗的产量。
