雷达系统可通过发射稀疏频谱波形(Sparse Frequency Waveform,SFW)克服同频窄带干扰问题,然而SFW通常具有较高的距离旁瓣,降低了弱小目标的检测性能。针对该问题,该文提出一种设计低距离旁瓣SFW的相位编码方法。该方法以联合最小化波形...雷达系统可通过发射稀疏频谱波形(Sparse Frequency Waveform,SFW)克服同频窄带干扰问题,然而SFW通常具有较高的距离旁瓣,降低了弱小目标的检测性能。针对该问题,该文提出一种设计低距离旁瓣SFW的相位编码方法。该方法以联合最小化波形功率谱密度均方差和距离旁瓣为准则建立目标函数,并提出一种基于快速傅里叶变换的循环迭代算法(Cycle Iterative Algorithm,CIA)求解目标函数获得最优相位编码波形。随后将该方法扩展至多输入多输出(Multiple-Input Multiple-Output,MIMO)雷达,设计一组具有良好自/互相关特性SFW的相位编码。该方法沿着使目标函数非递增的方向搜索,且无需求解共轭梯度,计算复杂度低,可快速设计并更新发射波形。仿真结果验证了该方法的有效性与灵活性。展开更多
Strawberry Fusarium wilt (SFW) is a systematic soil-borne disease caused by Fusarium oxysporum f.sp.fragaria (Fof),which infects the vascular bundles,blocking water and nutrient transport from roots to the aboveground...Strawberry Fusarium wilt (SFW) is a systematic soil-borne disease caused by Fusarium oxysporum f.sp.fragaria (Fof),which infects the vascular bundles,blocking water and nutrient transport from roots to the aboveground.It is a severe pathogen which spreads rapidly and destroys strawberry production.Finding a way to control this disease is of great scientific value and practical importance.In this study,three fungi were isolated from the vascular tissues of sick strawberries in the field.After DNA sequencing,they were identified as Fof,Aspergillus fumigatus and Trichoderma harzianum,respectively,among which the first two are pathogens and the third is a probiotic.All fungi were controlled by thiophanate-methyl (TM),a commercial fungicide.On PDA medium,20 mg·L^(-1)5-aminolevulinic acid (ALA),a natural non-protein amino acid,promoted T.harzianum proliferation,but inhibited Fof and A.fumigatus.In confrontation test,the growth of Fof or A.fumigatus was inhibited by T.harzianum and exogenous ALA promoted T.harzianum growth but significantly inhibited the pathogen growth.When three species of fungi were separately or combinedly inoculated on healthy strawberry plants,T.harzianum promoted plant growth and development while Fof or A.fumigatus caused growth retardation,where Fof directly caused leaf yellowing and plant wilting.When the plants inoculated with different fungus were treated with ALA,the results turned out that ALA alleviated SFW symptoms by bidirectionally promoting T.harzianum proliferation and inhibiting Fof and A.fumigatus.Thus,ALA might be used in comprehensively controlling SFW in strawberry industry.展开更多
基金funded by the Natural Science Foundation of China (Grant No.32172512)the Jiangsu Agricultural Science and Technology Innovation Fund[Grant No.CX(20)2023]+1 种基金the Jiangsu Special Fund for Frontier Foundation Research of Carbon Peaking and Carbon Neutralization (Grant No.BK20220005)a project funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions。
文摘Strawberry Fusarium wilt (SFW) is a systematic soil-borne disease caused by Fusarium oxysporum f.sp.fragaria (Fof),which infects the vascular bundles,blocking water and nutrient transport from roots to the aboveground.It is a severe pathogen which spreads rapidly and destroys strawberry production.Finding a way to control this disease is of great scientific value and practical importance.In this study,three fungi were isolated from the vascular tissues of sick strawberries in the field.After DNA sequencing,they were identified as Fof,Aspergillus fumigatus and Trichoderma harzianum,respectively,among which the first two are pathogens and the third is a probiotic.All fungi were controlled by thiophanate-methyl (TM),a commercial fungicide.On PDA medium,20 mg·L^(-1)5-aminolevulinic acid (ALA),a natural non-protein amino acid,promoted T.harzianum proliferation,but inhibited Fof and A.fumigatus.In confrontation test,the growth of Fof or A.fumigatus was inhibited by T.harzianum and exogenous ALA promoted T.harzianum growth but significantly inhibited the pathogen growth.When three species of fungi were separately or combinedly inoculated on healthy strawberry plants,T.harzianum promoted plant growth and development while Fof or A.fumigatus caused growth retardation,where Fof directly caused leaf yellowing and plant wilting.When the plants inoculated with different fungus were treated with ALA,the results turned out that ALA alleviated SFW symptoms by bidirectionally promoting T.harzianum proliferation and inhibiting Fof and A.fumigatus.Thus,ALA might be used in comprehensively controlling SFW in strawberry industry.
