【目的】探索稻田施用有机肥对稻田节肢动物群落、捕食性天敌与水稻害虫的影响,是否会引起水稻重要害虫发生风险。【方法】2017-2018年连续2年种植单季稻,在稻田中施用有机肥(Rice paddy field used organic manure,RPOM),以常规施用化...【目的】探索稻田施用有机肥对稻田节肢动物群落、捕食性天敌与水稻害虫的影响,是否会引起水稻重要害虫发生风险。【方法】2017-2018年连续2年种植单季稻,在稻田中施用有机肥(Rice paddy field used organic manure,RPOM),以常规施用化肥稻田(Rice paddy field used chemical fertilizer,RPCF)为对照,调查RPOM与RPCF的土壤肥力、稻田水生昆虫、捕食性天敌总体、稻田蜘蛛、稻田捕食性昆虫(地上部分)、水稻害虫及捕食性天敌的补偿猎物等功能团的发生时间动态与相关性,计算物种益害比与个体数量益害比。【结果】土壤中的碱解氮、有效磷、全磷、全钾的含量为RPOM显著高于RPCF(P<0.05),全氮与有机质含量RPOM极显著高于RPCF(P<0.01)。RPCF中水生昆虫的个体数量明显低于RPOM。摇蚊与弹尾虫的总个体数量RPOM与RPCF没有显著差异。2017年在RPOM中采集到水稻害虫17种,887头;在RPCF中采集到水稻害虫18种,917头,群落相似系数0.86。2018年在RPOM中采集到水稻害虫13种,1226头,在RPCF中采集到水稻害虫15种,2035头,群落相似系数0.71。RPCF的害虫个体数量显著高于RPOM。2017年在RPOM中采集到捕食性天敌41种,总个体数量1316头,在RPCF中采集到捕食性天敌31种,总个体数量989头,群落相似性0.83,Bray-Curtis距离为0.15。2018年在RPOM稻田中采集到捕食性天敌41种,总个体数量1537头,在RPCF稻田中采集到捕食性天敌36种,总个体数量1031头,群落相似性0.78,Bray-Curtis距离为0.31。连续2年捕食性天敌的物种丰富度为RPOM明显高于RPCF,且在2018年差异极显著(P<0.01),个体数量RPOM显著高于RPCF(P<0.05)。个体数量益害比值,2017年RPOM为1.86,RPCF为1.09,RPOM明显高于RPCF,但无显著差异(P>0.05);2018年RPOM为1.64,RPCF为0.62,RPOM显著高于RPCF(P<0.05)。【结论】复合微生物菌肥明显提高稻田土壤肥力;对捕食性天敌补偿猎物的个体数量没有明显影响;降低水稻害虫功能团的�展开更多
SiO_(2)-particle reinforced silicon rubber composite(SP-RSRC)is a widely utilized material that offers shock absorption protection to various engineering structures in impact environments.This paper presents a compreh...SiO_(2)-particle reinforced silicon rubber composite(SP-RSRC)is a widely utilized material that offers shock absorption protection to various engineering structures in impact environments.This paper presents a comprehensive investigation of the mechanical behavior of SP-RSRC under various strain rates,employing a combination of experimental,theoretical,and numerical analyses.Firstly,quasi-static and dynamic compression tests were performed on SP-RSRC utilizing a universal testing machine and split Hopkinson pressure bar(SHPB)apparatus.Nonlinear stress-strain relationships of SP-RSRC were obtained for strain rates ranging from 1×10^(−3) to 3065 s^(−1).The results indicated that the composite showed evident strain rate sensitivity,along with nonlinearity.Then,a nonlinear visco-hyperelastic constitutive model was developed,consisting of a hyperelastic component utilizing the 3rd-order Ogden energy function and a viscous component employing a rate-dependent relaxation time scheme.The model accurately characterized the dynamic mechanical response of SP-RSRC,effectively mitigating the challenge of calibrating an excessive number of material parameters inherent in conventional viscoelastic models.Furthermore,the simplified rubber material(SRM)model,integrated within the LS-DYNA software,was chosen to depict the mechanical properties of SP-RSRC in numerical simulations.The parameters of the SRM model were further calibrated based on the strain-stress relationships of SP-RSRC,as predicted by the developed nonlinear visco-hyperelastic constitutive model.Finally,an inverse ballistic experiment using a single-stage air gun was conducted for SP-RSRC.Numerical simulations of SHPB experiments and the inverse ballistic experiment were then performed,and the reliability of the calibrated SRM model was verified by comparing the results of experiments and numerical simulations.This study offers a valuable reference for the utilization of SP-RSRC in the realm of impact protection.展开更多
文摘【目的】探索稻田施用有机肥对稻田节肢动物群落、捕食性天敌与水稻害虫的影响,是否会引起水稻重要害虫发生风险。【方法】2017-2018年连续2年种植单季稻,在稻田中施用有机肥(Rice paddy field used organic manure,RPOM),以常规施用化肥稻田(Rice paddy field used chemical fertilizer,RPCF)为对照,调查RPOM与RPCF的土壤肥力、稻田水生昆虫、捕食性天敌总体、稻田蜘蛛、稻田捕食性昆虫(地上部分)、水稻害虫及捕食性天敌的补偿猎物等功能团的发生时间动态与相关性,计算物种益害比与个体数量益害比。【结果】土壤中的碱解氮、有效磷、全磷、全钾的含量为RPOM显著高于RPCF(P<0.05),全氮与有机质含量RPOM极显著高于RPCF(P<0.01)。RPCF中水生昆虫的个体数量明显低于RPOM。摇蚊与弹尾虫的总个体数量RPOM与RPCF没有显著差异。2017年在RPOM中采集到水稻害虫17种,887头;在RPCF中采集到水稻害虫18种,917头,群落相似系数0.86。2018年在RPOM中采集到水稻害虫13种,1226头,在RPCF中采集到水稻害虫15种,2035头,群落相似系数0.71。RPCF的害虫个体数量显著高于RPOM。2017年在RPOM中采集到捕食性天敌41种,总个体数量1316头,在RPCF中采集到捕食性天敌31种,总个体数量989头,群落相似性0.83,Bray-Curtis距离为0.15。2018年在RPOM稻田中采集到捕食性天敌41种,总个体数量1537头,在RPCF稻田中采集到捕食性天敌36种,总个体数量1031头,群落相似性0.78,Bray-Curtis距离为0.31。连续2年捕食性天敌的物种丰富度为RPOM明显高于RPCF,且在2018年差异极显著(P<0.01),个体数量RPOM显著高于RPCF(P<0.05)。个体数量益害比值,2017年RPOM为1.86,RPCF为1.09,RPOM明显高于RPCF,但无显著差异(P>0.05);2018年RPOM为1.64,RPCF为0.62,RPOM显著高于RPCF(P<0.05)。【结论】复合微生物菌肥明显提高稻田土壤肥力;对捕食性天敌补偿猎物的个体数量没有明显影响;降低水稻害虫功能团的�
文摘SiO_(2)-particle reinforced silicon rubber composite(SP-RSRC)is a widely utilized material that offers shock absorption protection to various engineering structures in impact environments.This paper presents a comprehensive investigation of the mechanical behavior of SP-RSRC under various strain rates,employing a combination of experimental,theoretical,and numerical analyses.Firstly,quasi-static and dynamic compression tests were performed on SP-RSRC utilizing a universal testing machine and split Hopkinson pressure bar(SHPB)apparatus.Nonlinear stress-strain relationships of SP-RSRC were obtained for strain rates ranging from 1×10^(−3) to 3065 s^(−1).The results indicated that the composite showed evident strain rate sensitivity,along with nonlinearity.Then,a nonlinear visco-hyperelastic constitutive model was developed,consisting of a hyperelastic component utilizing the 3rd-order Ogden energy function and a viscous component employing a rate-dependent relaxation time scheme.The model accurately characterized the dynamic mechanical response of SP-RSRC,effectively mitigating the challenge of calibrating an excessive number of material parameters inherent in conventional viscoelastic models.Furthermore,the simplified rubber material(SRM)model,integrated within the LS-DYNA software,was chosen to depict the mechanical properties of SP-RSRC in numerical simulations.The parameters of the SRM model were further calibrated based on the strain-stress relationships of SP-RSRC,as predicted by the developed nonlinear visco-hyperelastic constitutive model.Finally,an inverse ballistic experiment using a single-stage air gun was conducted for SP-RSRC.Numerical simulations of SHPB experiments and the inverse ballistic experiment were then performed,and the reliability of the calibrated SRM model was verified by comparing the results of experiments and numerical simulations.This study offers a valuable reference for the utilization of SP-RSRC in the realm of impact protection.
