研究主部为热传导算子的拟线性抛物型方程Cauchy问题:ut=uxx+(u^n)x,(x,t)∈S=R×(0.∞),u(x,0)=δ(x),x∈R.在一维情形下源型解的存在性,唯一性,不存在性,解的渐近性和相似源型解等问题.在研究过程中,找到了一个n的临界值,即n0=3.当0≤n〈n0时,方程源型解存在且唯一;当n≥n0时,方程不存在源型解;当0≤n〈2时,方程的源型解在原点附近渐近行为恰似热传导方程的基本解;应用量纲分析技巧,证明了当且仅当n=2时,方程存在唯一相似源型解,并求出了其解析表达式.研究结果表明了这类抛物型方程对流项的存在对扩散项产生莺要影响的物理事实.
This paper is interested in the following equation ut=uxx+(u^n)x,with a measure as its initial conditions. If its initial datum is a Dirac measure, it is shown that there exists a critical value n = 3 such that the existence and uniqueness of solutions of the problems as 0 ≤ n 〈 3 and the nonexistence of solutions of the problems as n ≥ 3 are true respectively. The author also studies the asymptotic behavior of its solution near (0, 0) as 0 ≤ n 〈 2 and similarity source-type solutions to the problems as n = 2.