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901.
902.
预应力曲线梁的实用计算方法   总被引:3,自引:0,他引:3  
针对流动坐标系的特性,采用与预应力直线梁计算相类似的分析方法,推导出曲线梁预应力钢束空间分析的计算表达式,利用空间曲梁单元在任意空间荷载作用下的等效节点力表达式,得出了一种实用的预应力曲线梁数值分析方法,并编制了相应的分析计算程序。最后结合深圳市某一预应力混凝土曲线高架桥的分析,计算结果与实测值相吻合。  相似文献   
903.
We classify flat strict nearly Kähler manifolds with (necessarily) indefinite metric. Any such manifold is locally the product of a flat pseudo-Kähler factor of maximal dimension and a strict flat nearly Kähler manifold of split signature (2m, 2m) with m ≥ 3. Moreover, the geometry of the second factor is encoded in a complex three-form $zeta in Lambda^3 (mathbb{C}^m)^*We classify flat strict nearly K?hler manifolds with (necessarily) indefinite metric. Any such manifold is locally the product of a flat pseudo-K?hler factor of maximal dimension and a strict flat nearly K?hler manifold of split signature (2m, 2m) with m ≥ 3. Moreover, the geometry of the second factor is encoded in a complex three-form . The first nontrivial example occurs in dimension 4m = 12.   相似文献   
904.
We survey recent developments which led to the proof of the Benson-Gordon conjecture on Kähler quotients of solvable Lie groups. In addition, we prove that the Albanese morphism of a Kähler manifold which is a homotopy torus is a biholomorphic map. The latter result then implies the classification of compact aspherical Kähler manifolds with (virtually) solvable fundamental group up to biholomorphic equivalence. They are all biholomorphic to complex manifolds which are obtained as a quotient of $mathbb{C}^{n}We survey recent developments which led to the proof of the Benson-Gordon conjecture on K?hler quotients of solvable Lie groups. In addition, we prove that the Albanese morphism of a K?hler manifold which is a homotopy torus is a biholomorphic map. The latter result then implies the classification of compact aspherical K?hler manifolds with (virtually) solvable fundamental group up to biholomorphic equivalence. They are all biholomorphic to complex manifolds which are obtained as a quotient of mathbbCnmathbb{C}^{n} by a discrete group of complex isometries.  相似文献   
905.
    
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906.
    
One of the present authors defined the infinitesimal harmonictransformation in a Riemannian manifold. This paperis devoted to the study of the local and global geometryinfinitesimal harmonic transformations.  相似文献   
907.
    
Let M be a compact complex manifold containing an irreducible curve C such that M — C is Kähler; in this paper we study the link between some cohomological properties of C and the obstructions to the existence of a Kähler metric on the whole of M. In particular we get that, if M is not Kähler, then C is a $ left({partial + bar partial} right) $ –exact current, or there exists a positive current S of bidimension (1, 1) such that $ partial bar partial S = 0,,chi _C S = 0 $ and S + C is $ left({partial + bar partial} right) $ –exact. If C is a smooth rational curve, more precise results are given in connection with the normal bundle NC|M.  相似文献   
908.
    
A Boutet de Monvel type calculus is developed for boundary value problems on (possibly) noncompact manifolds. It is based on a class of weighted symbols and Sobolev spaces. If the underlying manifold is compact, one recovers the standard calculus. The following is proven:
  • 1 The algebra G of Green operators of order and type zero is a spectrally invariant Fréchet subalgebra of L(H), H a suitable Hilbert space, i. e.,
  • 2 Focusing on the elements of order and type zero is no restriction since there are order reducing operators within the calculus.
  • 3 There is a necessary and sufficient criterion for the Fredholm property of boundary value problems, based on the invertibility of symbols modulo lower order symbols, and
  • 4 There is a holomorphic functional calculus for the elements of G in several complex variables.
  相似文献   
909.
    
Operators on a manifold with (geometric) singularities are degenerate in a natural way. They have a principal symbolic structure with contributions from the different strata of the configuration. We study the calculus of such operators on the level of edge symbols of second generation, based on specific quantisations of the corner‐degenerate interior symbols, and show that this structure is preserved under composition (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献   
910.
    
In this paper, we can prove that any non‐degenerate strongly harmonic map ? from a compact Berwald manifold with nonnegative general Ricci curvature to a Landsberg manifold with non‐positive flag curvature must be totally geodesic, which generalizes the result of Eells and Sampson ([2]).  相似文献   
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