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951.
DING Yong LU Shanzhen & ZHANG PuDepartment of Mathematics Beijing Normal University Beijing China Department of Information Computing Science Zhejiang Institute of Science Technology Hangzhou China 《中国科学A辑(英文版)》2004,47(1):83-95
In this paper the authors give the weighted weak L logL type estimates for a class of the higher order commutator generated by the Marcinkiewicz integral and a BMO function. In addition, the weak type norm inequalities for the Marcinkiewicz integral and its commutators with different weight functions are also discussed. 相似文献
952.
YongHuaLI HalBinKAN BingJunYU 《数学学报(英文版)》2004,20(3):569-576
In this paper, a special kind of partial algebras called projective partial groupoids is defined.It is proved that the inverse image of all projections of a fundamental weak regular ^*-semigroup under the homomorphism induced by the maximum idempotent-separating congruence of a weak regular ^*-semigroup has a projective partial groupoid structure. Moreover, a weak regular ^*-product which connects a fundamental weak regular ^*-semigroup with corresponding projective partial groupoid is defined and characterized. It is finally proved that every weak regular ^*-product is in fact a weak regular ^*-semigroup and any weak regular ^*-semigroup is constructed in this way. 相似文献
953.
JiongShengLI YongLiangPAN 《数学学报(英文版)》2004,20(5):803-806
We first apply non-negative matrix theory to the matrix K = D A, where D and A are the degree-diagonal and adjacency matrices of a graph G, respectively, to establish a relation on the largest Laplacian eigenvalue λ1 (G) of G and the spectral radius p(K) of K. And then by using this relation we present two upper bounds for λ1(G) and determine the extremal graphs which achieve the upper bounds. 相似文献
954.
Yong Su Shin 《Journal of Applied Mathematics and Computing》2004,15(1-2):201-210
We examine ak-configuration ${\mathbb{X}}$ in ?2 or ?3 whose minimal free resolution has a non-cancelable Betti number in the last free module. We also find partial answers to the question: which Artinian O-sequences are level or not? 相似文献
955.
Dynamics of split pulses in actively Q-switched fiber lasers are numerically investigated, and the mechanism that produces multipeak phenomena (MPP) is precisely illustrated. It is shown that the first transient pulse in a cavity is initiated by the quick switching of a Q-switching element, which actually injects part of the amplified spontaneous emission into the laser cavity in the form of a pulse. Then the multipeak structures are related to the evolution of the perturbation caused by the switching and are determined by the rise time of the switching and by conditions of photon density and population inversion. 相似文献
956.
265Bh(Z=107)同位素的首次观测 总被引:1,自引:0,他引:1
在兰州的重离子加速器上用26Mg离子束轰击243Am靶,产生了新同位素265Bh.通过观测新同位素265Bh和它的已知子核261Db和257Lr之间的α衰变的关联,实现了对新核素的鉴别.实验中使用了一套新建立的具有数个探测器对的转轮收集探测系统.将该系统用于特殊的母–子核搜索模式,从而大大减少了本底.共测得了8个265Bh的α衰变关联事件;同时4个已知核264Bh的衰变关联事件也被鉴别出来.实验测得265Bh的α衰变能量为(9.24±0.05)MeV,半衰期为0.94+0.70–0.31s. 相似文献
957.
VEGF expressed in glomerular podocytes, is known to increase vascular permeability to macromolecules. Angiotensin II can stimulate the release of VEGF, and the protective effects of angiotensin II antagonist against diabetic glomerular injury suggest that the angiotensin II-induced VEGF is an important pathogenetic mechanism in the development of proteinuria during diabetic nephropathy although this mechanism is not fully understood. In this study, the changes of VEGF expression was examined in the experimental diabetic nephropathy to determine whether these changes were modified by renoprotective intervention by blockers of angiotensin II receptors. The streptozotocin- induced diabetic rats were treated with L-158,809, a blocker of angiotensin II receptors, for 12 weeks. Age-matched rats with L-158,809 served as controls. RT-PCR and immunohistochemistry were used to assess and quantify gene and protein expression of VEGF. A progressive increase in urinary protein excretion was observed in diabetic rats. Glomerular VEGF expression was significantly higher in diabetic rats than in the control groups, with a significant reduction in glomerular VEGF expression and proteinuria in L-158,809- treated diabetic rats. VEGF mRNA was also significantly higher in diabetic kidneys than in the control groups, with a significant reduction in VEGF mRNA in L-158,809-treated diabetic kidneys. These results demonstrates that VEGF expression is significantly increased in diabetic podocytes, and angiotensin II receptor antagonist attenuated these changes in VEGF expression and prevented the development of proteinuria in vivo. Attenuation of increased VEGF expression in podocytes could contribute to the renoprotective effects of angiotensin II receptor antagonists in diabetic nephropathy. 相似文献
958.
A high-density array of vertically aligned ZnGa(2)O(4) nanowires has been synthesized on Si substrates via CVD of ZnO-Ga at 1000 degrees C consisting of a single-crystalline cubic spinel structure grown in a [111] direction and exhibiting strong photoluminescence and cathodoluminescence in the blue wavelength region. 相似文献
959.
Kang YS Lee HI Zhang Y Han YJ Yie JE Stucky GD Kim JM 《Chemical communications (Cambridge, England)》2004,(13):1524-1525
Highly ordered mesoporous materials constructed with integrated polymer-silica hybrid frameworks can be obtained via a one-step synthetic strategy using a mixture of polymer and silicate as the framework sources in the presence of a structure-directing agent. 相似文献
960.
Two-loop renormalization group equations in the standard model are recalculated. A new coefficient is found in the beta function of the quartic coupling and a class of gauge invariants is found to be absent in the beta functions of hadronic Yukawa couplings. The two-loop beta function of the Higgs mass parameter is presented in complete form. 相似文献