In this paper, we study the mean curvature flows of convex hypersurface in Euclidean spaces in two situations: n = 1 and n≥2. we use evolution equations of their first and second fundamental forms and the maximum principle to get somestructual results on the shape of Mω.Specifically, we prove the following theorems.Theoremâ… Suppose 7o is a closed convex curve.Then the solutionγ(,t) ofthe evolution equation with 7o as intial curve exists only at a finite timeinterval [0,ω) .Furthermore, as t→ω, the solutionγ(,t) converges to a piont.Theoremâ…¡Let n≥2 and M is a compact without boundary n -dimensional manifold, F0 is a smooth hypersurface immersion of Mn into Rn+1 , the intialsurface M0 is smooth,compact without boundary and with positive mean curvature, Suppose that Ft : Mn→Rn+1 be a one-parameter family of smooth hypersurface immersions in Euclidean space,Then the solution F(,t) of evolution equation(where H(p,t) and v(p,t) are the mean curvature and unitnormal at ( p,t ) on Mt respectively ) exists a maximal time interval 0≤t <ω<∞.Moreover as t→ω,F(,t) converges to a piont. Furthermore, ast→ω,maxMt |A|2 becomes unbounded.Theoremâ…¢The third fundamental form satisfies the evolution equation (?)/(?)t bij=â–³bij+2|A|2bij - 2HbijHjpglp-2gij|â–½H|2...
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