Evidence for transmission of aphid-pathogenic fungi by migratory flight of Myzus persicae alates

The alates of the green peach aphid, Myzus persicae, were daily trapped from the air from late October through early January and carried to laboratory for determination of fungal infection by individually rearing them for 7 d on detached cabbage leaves in Petri dishes. Among 760 alates trapped, 266 (35%) were found carrying various fungal pathogens, 87.3% of them died due to mycosis during the first 3-day period of rearing and the rest died in the following two days. Most of the deaths of the alates were attributed to entomophthoralean fungi, taking 94.4%, and the rest were the hyphomycetous fungus Beauveria bassiana. Among the Entomophthorales-killed alates, P. neoaphidis took a proportion of 66.1%, Z. anhuiensis 22.6%, E. planchoniana 9.7%, and N. fresenii 1.6%, respectively. Two alates were found suffering from cross infection of two fungal species, i.e. P. neoaphidis with Z. anhuiensis and N. fresenii, respectively. The results represent the first report on transmission of aphid-pathogenic fungi by M. persicae alates through migratory flight.     

含慢变量双参数的非线性系统初值问题的奇摄动

研究含慢变量双参数的非线性系统初值问题的奇摄动,通过两参数量级的比较,揭示了初始层呈现的"层中层"现象,并利用对角化技巧,通过逐步逼近,证明了渐近解的一致有效性.     

Banach空间中一阶初值问题整体解的存在性

在紧型条件下研究了一般Banach空间中一阶微分方程初值问题整体解的存在性。利用非紧性测度的性质与凝聚映射的Sadovskii不动点定理， 获得了2个整体解的存在性结果。     

不对称倍压整流电路的S域分析

利用倍压整流电路的S域模型设计一种算法,详细推导不对称倍压整流电路的充电过程,导出定量计算电容器电压的数学表达式,利用所得表达式对对称,非对称倍压整流电路进行讨论,绘出了电容器电压充电曲线,并证明达到倍压目的所经历的充电周期数。     

论微重力弹-环状流转换的空隙率匹配模型

对基于微重力条件下,气／液两相弹状流滑移流率关系和光滑环状流动量平衡关系的弹-环状流转换空隙率匹配模型的解的特征,进行了深入分析．发现该模型具有双解、单解和无解三种情况．由此阐明了该模型难以正确预测微重力条件下气／液两相弹-环．状流转换条件的原因在于光滑环状流动量平衡关系的非客观性．     

20g钢断裂性质的研究

本文实验测试了预应变对20g钢断裂韧性的影响.在弹塑性有限元数值分析的基础上,讨论了裂纹尖端张开位移与最大应变间的关系及预应变量ε_p对临界断裂应变的影响.同时,在Rice-Tracey空穴扩张模型的基础上,探讨了裂纹前方空穴形成的原因及主裂纹扩展的条件,分析了预应变量ε_p对20g钢断裂性质的影响.     

非线性拟抛物方程解的熄灭

本文采用特征函数法与积分估计法研究两类非线性拟抛物方程的初边值问题解的熄灭问题,分别给出了其古典解与广义解熄灭的两种较为广泛的充分条件.     

强耦合抛物组解的整体存在性和不存在性

本文利用半群方法证明了一类强耦合非线抛物型方程组初边值问题的整体解存在性；用特征函数方法，给出了整体解不存在的一个充分条件。     

一类高阶多变量的非线性伪双曲方程组的周期边值问题与初值问题

本文利用能量积分估计Leray—Schauder不动点证明了一类高阶多变量的非线性伪双曲方程组的周期边值问题和初值问题广义解的存在性与唯一性.     

变幅等速肌力矩测试的前置效应及其机制

全幅或定幅等速肌力矩测试结果中某一时点的数据不能很好地反映运动实践中与该时点相对应的关节解剖位相的肌肉功能性态.变幅等速测试中由于起始角不同造成的肌肉收缩初长度各异是影响肌肉功能的重要因素,是一种前置效应.测试结束角不同不会产生显著影响.建议等速测试按不同技术动作、不同运动幅度、不同运动速度进行设计.