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371.
拟线性双曲型方程组的奇性 总被引:1,自引:0,他引:1
考虑一类拟线性退化特征双曲型方程组Cauchy问题,利用特征线法和局部延拓法证明了其经典解的整体存在性.结果表明,对于具退化特征双曲型方程组Cauchy问题在一定条件下存在整体经典解. 相似文献
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374.
考察一类描述吸引Bose Einstein凝聚(BEC)的二维阻尼Gross Pitaevskii(GP)方程iφt=-Δφ+|x|2φ-|φ|2φ+ia|φ|4φ,t≥0,x∈R2,a<0.借鉴文献(CommunMathPhys,1983,87:567~576.)关于经典Schr dinger方程研究的思想和结果,建立GP方程与一个经典的非线性数量场方程的对应关系,得到方程的整体解存在的一个充分条件. 相似文献
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376.
具功能反应的食饵与捕食者两种群模型的极限环 总被引:1,自引:0,他引:1
研究了具功能反应的食饵与捕食者两种群模型:{dx/dt=x(θ1 θ2x-θ3x^2-y),dy/dt=y(-1 x).讨论了该系统平衡点的性态,并证明了权限环的存在性与惟一性及其全局稳定性。 相似文献
377.
本文讨论了一类带记忆边界条件的半线性抛物型方程的爆破问题.利用上下解方法,结合积分估计本文给出了方程的解在有限时刻爆破或整体存在的充分条件,并证明了某些条件下解的爆破只能在边界上发生. 相似文献
378.
A grid-by-grid counting of interdecadal trend turning (ITT) of annual mean surface air temperature (SAT) and total precipitation at 67,359 terrestrial grids in the period 1951–2002 is presented. An analysis of the last ITTs of SAT and total precipitation in the period, in the context of both occurrence time and linear trends after the breakpoint, indicates that a warming trend has become highly significant across most of the world in the late 20th Century. Most terrestrial grids have recorded an ITT of total precipitation in either the 1970s or 1980s, and 45.7% of the terrestrial grids in the study have seen a decreasing trend in total annual precipitation after the breakpoint, with the remaining 54.3% having experienced an increasing trend. Basically, global terrestrial regions have experienced either an increasingly warm and dry climate or an increasingly warm and wet climate. An analysis of ITT of regional mean SAT and total precipitation in 22 regions shows the northern American continent has become increasingly warm and dry after the last inter-decadal breakpoint. Meanwhile, the African continent has become increasingly warm and wet, with both Europe and most of Asia having the same trend. Southern South America and the west of Australia have experienced an opposite trend in climate, becoming increasingly cold and wet. 相似文献
379.
Let K be a global quadratic ?eld, then every unrami?ed abelian extension of K is proved to be absolutely Galois when K is a number
?eld or under some natural conditions when K is a function ?eld. The absolute Galois group is also determined explicitly. 相似文献
380.
A grid-by-grid counting of interdecadal trend turning (ITT) of annual mean surface air temperature (SAT) and total precipitation at 67,359 terrestrial grids in the period 1951-2002 is presented. An analysis of the last ITTs of SAT and total precipitation in the period, in the context of both occurrence time and linear trends after the breakpoint, indicates that a warming trend has become highly significant across most reagent of the world in the late 20th Century. Most terrestrial grids have recorded an ITT of total precipitation in either the 1970s or 1980s, and 45.7% of the terrestrial grids in the study have seen a decreasing trend in total annual precipitation after the breakpoint, with the remaining 54.3% having experienced an increasing trend. Basically, global terrestrial regions have experienced either an increasingly warm and dry climate or an increasingly warm and wet climate. An analysis of ITT of regional mean SAT and total precipitation in 22 regions shows that the Northern American continent has become increasingly warm and dry after the last interdecadal breakpoint. Meanwhile, the African continent has become increasingly warm and wet, with both Europe and most of Asia having the same trend. Southern South America and the West of Australia have experienced an opposite trend in climate, becoming increasingly cold and wet. 相似文献