： We consider an approximation problem related to strongly irreducible operators, that is, does the direct sum of a strongly irreducible operator in B∞（Ω） and certain operator have a small compact perturbation wh...： We consider an approximation problem related to strongly irreducible operators, that is, does the direct sum of a strongly irreducible operator in B∞（Ω） and certain operator have a small compact perturbation which is a strongly irreducible operator in B∞（Ω）？ In this paper, we prove that the direct sum of any strongly irreducible operator in B∞（Ω） and certain biquasitriangular operator have small compact perturbations which are strongly irreducible operators in B∞（Ω）.展开更多
Let (X, ρ) be a metric space and ↓USCC(X) and ↓CC(X) be the families of the regions below all upper semi-continuous compact-supported maps and below all continuous compact-supported maps from X to I = [0,1], respec...Let (X, ρ) be a metric space and ↓USCC(X) and ↓CC(X) be the families of the regions below all upper semi-continuous compact-supported maps and below all continuous compact-supported maps from X to I = [0,1], respectively. With the Hausdorff-metric, they are topological spaces. In this paper, we prove that, if X is an infinite compact metric space with a dense set of isolated points, then (↓USCC(X), ↓CC(X)) ≈ (Q, c 0 ∪ (Q Σ)), i.e., there is a homeomorphism h:↓USCC(X) → Q such that h(↓CC(X)) = c 0 ∪ (Q Σ), where Q = [?1,1]ω, Σ = {(x n ) n∈? ∈ Q: sup|x n | < 1} and c 0 = {(x n ) n∈? ∈ Σ: lim n→+∞ x n = 0}. Combining this statement with a result in our previous paper, we have $$ ( \downarrow USCC(X), \downarrow CC(X)) \approx \left\{ \begin{gathered} (Q,c_0 \cup (Q\backslash \Sigma )), if the set of isolanted points is dense in X, \hfill \\ (Q,c_0 ),otherwise, \hfill \\ \end{gathered} \right. $$ if X is an infinite compact metric space. We also prove that, for a metric space X, (↓USCC(X), ↓CC(X)) ≈ (Σ, c 0) if and only if X is non-compact, locally compact, non-discrete and separable.展开更多
This paper is concerned with the blow-up solutions of the Gross-Pitaevskii equation. Using the concentration compact principle and the variational characterization of the corresponding ground state, we obtain the limi...This paper is concerned with the blow-up solutions of the Gross-Pitaevskii equation. Using the concentration compact principle and the variational characterization of the corresponding ground state, we obtain the limiting profile of blow-up solutions with critical mass in the corresponding weighted energy space. Moreover, we extend this result to small super-critical mass case by the variational methods and scaling technique.展开更多
XRD,SEM及MFM观察表明,Nd Fe B粉末压坯在液相烧结过程中同时存在两种影响主相晶粒取向度的机制:烧结过程中大颗粒吞并吸附在其表面的取向不良的小晶粒并择优长大,使磁体的取向度提高;在液相烧结过程中,被液相所包围的主相晶粒的自由转...XRD,SEM及MFM观察表明,Nd Fe B粉末压坯在液相烧结过程中同时存在两种影响主相晶粒取向度的机制:烧结过程中大颗粒吞并吸附在其表面的取向不良的小晶粒并择优长大,使磁体的取向度提高;在液相烧结过程中,被液相所包围的主相晶粒的自由转动,造成磁体的取向度降低。对于取向度较低的DP生坯,烧结中影响Nd Fe B磁体取向度的前一种机制是主导的;而对于取向度较高的振动RIP生坯,烧结过程中后一种机制起主导作用。展开更多
基金The Specialized Research Fund (20050183002) for the Doctoral Program of Higher Educationthe NNSF (10371049 and J0630104) of China.
文摘： We consider an approximation problem related to strongly irreducible operators, that is, does the direct sum of a strongly irreducible operator in B∞（Ω） and certain operator have a small compact perturbation which is a strongly irreducible operator in B∞（Ω）？ In this paper, we prove that the direct sum of any strongly irreducible operator in B∞（Ω） and certain biquasitriangular operator have small compact perturbations which are strongly irreducible operators in B∞（Ω）.
基金supported by National Natural Science Foundation of China (Grant No. 10471084)
文摘Let (X, ρ) be a metric space and ↓USCC(X) and ↓CC(X) be the families of the regions below all upper semi-continuous compact-supported maps and below all continuous compact-supported maps from X to I = [0,1], respectively. With the Hausdorff-metric, they are topological spaces. In this paper, we prove that, if X is an infinite compact metric space with a dense set of isolated points, then (↓USCC(X), ↓CC(X)) ≈ (Q, c 0 ∪ (Q Σ)), i.e., there is a homeomorphism h:↓USCC(X) → Q such that h(↓CC(X)) = c 0 ∪ (Q Σ), where Q = [?1,1]ω, Σ = {(x n ) n∈? ∈ Q: sup|x n | < 1} and c 0 = {(x n ) n∈? ∈ Σ: lim n→+∞ x n = 0}. Combining this statement with a result in our previous paper, we have $$ ( \downarrow USCC(X), \downarrow CC(X)) \approx \left\{ \begin{gathered} (Q,c_0 \cup (Q\backslash \Sigma )), if the set of isolanted points is dense in X, \hfill \\ (Q,c_0 ),otherwise, \hfill \\ \end{gathered} \right. $$ if X is an infinite compact metric space. We also prove that, for a metric space X, (↓USCC(X), ↓CC(X)) ≈ (Σ, c 0) if and only if X is non-compact, locally compact, non-discrete and separable.
基金supported by National Natural Science Foundation of China (Grant No. 10771151)Scientific Research Fund of Sichuan Provincial Education Department (Grant No. 2006A068)
文摘This paper is concerned with the blow-up solutions of the Gross-Pitaevskii equation. Using the concentration compact principle and the variational characterization of the corresponding ground state, we obtain the limiting profile of blow-up solutions with critical mass in the corresponding weighted energy space. Moreover, we extend this result to small super-critical mass case by the variational methods and scaling technique.
文摘XRD,SEM及MFM观察表明,Nd Fe B粉末压坯在液相烧结过程中同时存在两种影响主相晶粒取向度的机制:烧结过程中大颗粒吞并吸附在其表面的取向不良的小晶粒并择优长大,使磁体的取向度提高;在液相烧结过程中,被液相所包围的主相晶粒的自由转动,造成磁体的取向度降低。对于取向度较低的DP生坯,烧结中影响Nd Fe B磁体取向度的前一种机制是主导的;而对于取向度较高的振动RIP生坯,烧结过程中后一种机制起主导作用。
