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51.
52.
LIN YaNan & WANG MinXiong School of Mathematical Sciences Xiamen University Xiamen China School of Mathematical Sciences Huaqiao University Quanzhou 《中国科学 数学(英文版)》2010,(4)
In this paper,we prove that if a triangulated category D admits a recollement relative to triangulated categories D' and D″,then the abelian category D/T admits a recollement relative to abelian categories D'/i(T) and D″/j(T) where T is a cluster tilting subcategory of D and satisfies i i (T) T,j j (T) T. 相似文献
53.
Zhaoming Zhang Christopher J. Howard Kevin S. Knight 《Journal of solid state chemistry》2007,180(6):1846-1851
The crystal structure of the A-site deficient perovskite Ln1/3NbO3 (Ln=Nd, Pr) at room temperature has been determined, for the first time, as orthorhombic in space group Cmmm using high-resolution neutron powder diffraction. Pertinent features are the alternation of unoccupied layers of A-sites and layers partly occupied by Ln cations, as well as out-of-phase tilting of the NbO6 octahedra around an axis perpendicular to the direction of the cation/vacancy ordering. The phase transition behaviour of Nd1/3NbO3 has also been studied in situ. This compound undergoes a continuous phase transition at around 650 °C to a tetragonal structure in space group P4/mmm due to the disappearance of the octahedral tilting. The analysis of spontaneous strains shows that this phase transition is tricritical in nature. 相似文献
54.
《Current Applied Physics》2014,14(1):46-52
The phase assemblage, crystal structure evolution and microwave dielectric response of (Ca0.5+xSr0.5−x)[(Al0.5Nb0.5)0.5Ti0.5]O3 ceramics (abbreviated as CSANT hereafter) are investigated. Single perovskite solid solution is formed in the CSANT ceramics in Sr-rich composition range of x < −0.05, however, Ca4Ti3O10-type layered perovskite phase begins to segregate after x = −0.05. The CSANT perovskites crystallized in Fm3m cubic symmetry in the composition range of x ≤ −0.2, however, as the Ca2+ content in A-site increased, the oxygen octahedral began to be anti-phase tilted at x = −0.1 and the crystal structure transited to P21/n pseudo-orthorhombic space group thereafter. The microwave dielectric response of the CSANT ceramics is elaborately discussed in terms of their crystallographic structure and chemical composition. When sintered at 1500 °C for 4 h, a dielectric constant ɛr of 52.5, a Qf product of 28000 GHz and a τf of +25.4 ppm/°C microwave dielectric ceramic can be obtained in the CSANT ceramics at x = 0.3. 相似文献
55.
XiaoJin Zhang 《中国科学 数学(英文版)》2012,55(6):1171-1178
We build a connection between iterated tilted algebras with trivial cluster tilting subcategories and tilted algebras of finite type.Moreover,all tilted algebras with cluster tilting subcategories are determined in terms of quivers.As a result,we draw the quivers of Auslander’s 1-Gorenstein algebras with global dimension 2 admitting trivial cluster tilting subcategories,which implies that such algebras are of finite type but not necessarily Nakayama. 相似文献
56.
Let A be a finite dimensional hereditary algebra over an algebraically closed field and A (m) be the mth replicated algebra of A. We prove that if T is a faithful almost complete tilting A (m)-module with pd A (m) T ≤ m, then T has exactly m + 1 indecomposable nonisomorphic complements with projective dimensions at most m. Moreover, we give an explicit distribution of the complements to T. 相似文献
57.
T. Pagnier C. Galven J.L. Fourquet M.P. Crosnier-Lopez 《Journal of solid state chemistry》2009,182(2):317-326
The crystal structure of the Ruddlesden-Popper layered perovskite Li2SrTa2O7 has been characterized at various temperatures between −185 and 300 °C by several techniques: X-ray and neutron powder diffraction, single crystal diffraction, transmission electron microscopy and Raman spectroscopy. The low temperature structure has been confirmed to be orthorhombic Cmcm with a small octahedra antiphase tilting (ΦΦ0) (ΦΦ0) inside the perovskite blocks. With temperature, the tilting progressively vanishes leading around 230 °C to a tetragonal symmetry (S.G. I4/mmm). This reversible phase transition, followed by X-ray and neutron thermodiffraction and thermal Raman measurements, is considered as of second order. An attribution of the Raman bands based on normal mode analysis is proposed. 相似文献
58.
代数表示理论是上个世纪七十年代初兴起的代数学的—个新的分支,而倾斜理论是研究代数表示理论的重要工具之一.本文主要对Dn型路代数倾斜模在其对应的AR-箭图上的结构特点进行研究.通过对Dn型路代数A的AR-箭图ΓA分析,证明了:Dn型路代数倾斜模T的—个必要条件是。〈T〉中至少有三个边缘点. 相似文献
59.
Exceptional Sequences Determined by their Cartan Matrix 总被引:1,自引:0,他引:1
We investigate complete exceptional sequences E=(E
1,¨,E
n
) in the derived category D
b
of finite-dimensional modules over a canonical algebra, equivalently in the derived category D
b
X of coherent sheaves on a weighted projective line, and the associated Cartan matrices C(E)=( [E
i
],[E
j
]). As a consequence of the transitivity of the braid group action on such sequences we show that a given Cartan matrix has at most finitely many realizations by an exceptional sequence E, up to an automorphism and a multi-translation (E
1,¨,E
n
)(E
1[i
1],¨,E
n
[i
n
]) of D
b
. Moreover, we determine a bound on the number of such realizations. Our results imply that a derived canonical algebra A is determined by its Cartan matrix up to isomorphism if and only if the Hochschild cohomology of A vanishes in nonzero degree, a condition satisfied if A is representation-finite. 相似文献
60.
Andrei Marcus 《Proceedings of the American Mathematical Society》2004,132(1):7-14
We establish Broué's abelian defect group conjecture for the alternating groups, using the Chuang-Rouquier theorem (proving this for the symmetric groups) and a descent result.