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991.
S. P. Wang L. J. Xu Z. H. Gao R. F. Wang 《Russian Journal of Coordination Chemistry》2010,36(10):786-792
A terbium p-methyl benzoate complex with 1,10-phenanthroline, [Tb(p-MBA)3(Phen)]2 (p-MBA = p-methyl benzoate and Phen = 1,10-phenanthroline), has been prepared and structurally characterized by X-ray diffraction. It crystallizes in triclinic system, space group P \(\bar 1\) with a = 12.8064(12), b = 13.3589(12), c = 19.8277(19) Å, α = 91.668(2)°, β = 97.775(2)°, γ = 106.312(2)°, C72H58N4O12Tb2, M r = 1489.06, V = 3217.6(5) Å3, Z = 2, ρ c = 1.537 g/cm3, μ(MoK α) = 2.246 mm?1, F(000) = 1488, the final R = 0.0622 and wR = 0.0962 for 14128 independent reflections with R int = 0.0843. It consists of two types of crystallographically independent dimeric molecules [Tb(p-MBA)3(Phen)]2 noted as [Tb-1] and [Tb-2]. In the dimeric molecule [Tb-1], each Tb(III) is eight-coordinated with one Phen molecule, two bridging carboxylate groups, and two bidentate chelating carboxylate groups, while in [Tb-2] each Tb(III) is eight-coordinated with one Phen molecule, four bridging carboxylate groups, and one bidentate chelating carboxylate group. The title complex shows intense green luminescence under UV light at room temperature. 相似文献
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该文利用辛空间上的子空间构造了一类新的d z析取矩阵,然后研究了如下排列问题:对于给定的整数m, r, s,ν, d, q 和辛空间F2ν q中的一个(m, s) 型子空间S, 这里ν+s≥ m>r≥2s-1≥1, d≥2,q 是一个素数的幂, 作者从S中找到d个(m-1, s-1) 型子空间H1,… Hd, 使包含在这些(m-1, s-1) 型子空间中的(r, s-1)型子空间个数达到最大. 然后利用这个排列的有关结论, 给出了一类pooling设计的紧界. 相似文献
997.
Yuanyuan Wang 《Communications in Nonlinear Science & Numerical Simulation》2012,17(10):3967-3978
In this article, by a nonstandard finite-difference (NSFD) scheme we study the dynamics of the delay differential equation with unimodal feedback. First, under three cases local stability of the equilibria is discussed according to Schur polynomial and Hopf bifurcation theory of discrete system. Then, the explicit algorithms for determining the direction of the Hopf bifurcation and the stability of the bifurcating periodic solutions are derived, using the normal form method and center manifold theorem. In Section 4, numerical example using Nicholson’s blowflies equation is provided to illustrate the theoretical results. Finally, it demonstrates significant superiority of nonstandard finite-difference scheme than Euler method under the means of describing approximately the dynamics of the original system. 相似文献
998.
A family ( X, B1 ), (X, B2 ), . . . , (X, Bq ) of q STS(v)s is a λ-fold large set of STS(v) and denoted by LSTS λ (v) if every 3-subset of X is contained in exactly λ STS(v)s of the collection. It is indecomposable and denoted by IDLSTS λ (v) if there does not exist an LSTS λ'(v) contained in the collection for any λ' λ. In this paper, we show that for λ = 5, 6, there is an IDLSTS λ (v) for v ≡ 1 or 3 (mod 6) with the exception IDLSTS6 (7). 相似文献
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Yichang MengShumin Zhang Xinzhan WangJuan Du Hongfei LiYanping Hao Xingliang Li 《Optics and Lasers in Engineering》2012,50(3):303-307
We have demonstrated an adjustable double-clad Yb3+-doped fiber laser using a double-pass Mach-Zehnder interferometer. The laser is adjustable over a range of 40 nm from 1064 nm to 1104 nm. By adjusting the state of the polarization controller, which is placed in the double-pass Mach-Zehnder interferometer, we obtained central lasing wavelengths that can be accurately tuned with controllable spacing between different tunable wavelengths. The laser has a side mode suppression ratio of 42 dB, the 3 dB spectral width is less than 0.2 nm, and the slope efficiencies at 1068 nm, 1082 nm and 1098 nm are 23%, 32% and 26%, respectively. In addition, we have experimentally observed tunable multi-wavelengths lasing output. 相似文献