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71.
DUAL RECIPROCITY HYBRID BOUNDARY NODE METHOD FOR THREE-DIMENSIONAL ELASTICITY WITH BODY FORCE 总被引:1,自引:0,他引:1
Combining Dual Reciprocity Method (DRM) with Hybrid Boundary Node Method (HBNM), the Dual Reciprocity Hybrid Boundary Node Method (DRHBNM) is developed for three-dimensional linear elasticity problems with body force. This method can be used to solve the elasticity problems with body force without domain integral, which is inevitable by HBNM. To demonstrate the versatility and the fast convergence of this method, some numerical examples of 3-D elasticity problems with body forces are examined. The computational results show that the present method is effective and can be widely applied in solving practical engineering problems. 相似文献
72.
Abed Al-Aziz Al-Quntar 《Journal of organometallic chemistry》2005,690(10):2504-2514
This article describes our recent methods for the synthesis of substituted vinylphosphonates by reacting 1-alkynylphosphnates with group (IV) complexes. cis-Vinylphosphonates, 1,3-butadienylphosphonates, 1-(hydroxymethyl)vinylphosphonates, 2-(hydroxymethyl)vinylphosphonates, (E) 3-oxo-1-alkenylphosphonates were produced as a result of the reactions between zirconium complexes and 1-alkynylphosphonates. On the other hand, titanium complexes afford 3-aminovinylphoshonates, 1,4-bis-phosphonates, and various other di- and tri-substituted vinylphosphonates. An evaluation of access of these recently synthesized vinylphosphonates as MMP-2 inhibitors has shown that certain compounds are very potent and promising. 相似文献
73.
The polycrystalline sample of layered compound FePS_3 has been investigated by using M?ssbauer spectroscopy (12K to 300K), magnetic susceptibility measurements, x-ray diffraction and FTIR spectroscopy. The antiferromagnetic order exists below T_N=120.5±1K. The M?ssbauer spectra below T_N indicate that the magnetization axis is perpendicular to the layer of FePS_3, and the divalent iron cations are in their high spin configurations. By fitting the hyperfine field parameters near the Néel temperature, we obtain information on the nature of magnetic interactions in the material. The results show that the magnetic coupling can be treated by the two-dimensional Ising model, and it can be interpreted on the basis of a crystal-field effect. 相似文献
74.
第二类变型Bessel函数Kn(z)在自变量趋于无穷时就是指数变小的,使用多项式逼近的方法求解往往误差很大.采用指数变换和J.P.Boyd的有理Chebyshev多项式计算第二类变型Bessel函数,得到了令人满意的在较大范围内有效的解. 相似文献
75.
Johan van Benthem 《Logica Universalis》2007,1(1):125-138
We prove new Lindstr?m theorems for the basic modal propositional language, and for some related fragments of first-order
logic. We find difficulties with such results for modal languages without a finite-depth property, high-lighting the difference
between abstract model theory for fragments and for extensions of first-order logic. In addition we discuss new connections
with interpolation properties, and the modal invariance theorem.
Mathematics Subject Classification (2000): Primary 03B45; Secondary 03C95 相似文献
76.
Chen Yongnian 《模糊系统与数学》1995,(1)
ANTIFUZZYVECTORSPACES(Ⅱ)ChenYongnian(DepartmentofMathematics,XinjiangNormalUniversity,830054,Xinjiang,P.R.China)ANTIFUZZYVECT... 相似文献
77.
调制不稳定性对级联放大光纤传输系统信噪比的影响 总被引:1,自引:0,他引:1
在考虑光纤损耗和级联放大器的情况下,推导了调制不稳定性的产生条件和增益的普适解析表达式,分析了调制不稳定性对信噪比的影响,给出了一个新的计算信噪比的表达式。 相似文献
78.
Rüdiger Schultz Leen Stougie Maarten H. van der Vlerk 《Mathematical Programming》1998,83(1-3):229-252
In this paper we present a framework for solving stochastic programs with complete integer recourse and discretely distributed right-hand side vector, using Gröbner basis methods from computational algebra to solve the numerous second-stage integer programs. Using structural properties of the expected integer recourse function, we prove that under mild conditions an optimal solution is contained in a finite set. Furthermore, we present a basic scheme to enumerate this set and suggest improvements to reduce the number of function evaluations needed. 相似文献
79.
B. Hannoyer A. A. M. Prince M. Jean R. S. Liu G. X. Wang 《Hyperfine Interactions》2006,167(1-3):767-772
Crystalline LiFePO4 has been synthesized using solid-state, spray pyrolysis, and wet chemical methods. The crystal parameters were obtained from Rietveld’s refinement methods of the X-ray diffraction patterns. A detailed investigation of the Fe valency carried out using Mössbauer spectroscopy at room temperature indicates that Fe is predominantly present in its bivalent state. 相似文献
80.
A. Paesano Jr. S. C. Zanatta S. N. De Medeiros L. F. CÓtica J. B. M. Da Cunha 《Hyperfine Interactions》2005,161(1-4):211-220
We have investigated the mechanosynthesis of gadolinium and yttrium iron garnets by high-energy ball-milling of α-Fe2O3 and Gd2O3 or α-Fe2O3 and Y2O3, respectively, followed by short thermal annealings conducted at moderate temperatures. The samples were characterized by X-ray diffraction and Mössbauer spectroscopy, in order to determine the influence of the milling time and annealing conditions on the final products. For as-milled samples of each rare-earth system, the results revealed the formation of perovskite phases, in relative amounts that depend on the milling time. The formation of garnet phases was observed in as-annealed samples treated at 1000°C for 2 h or 1100°C for 3 h, i.e., at very modest annealing requirements when compared with ordinary solid-state-reaction processes performed without previous high-energy milling. Also, the occurrence was verified of a milling time for which the relative amount of garnet phases formed by annealing was maximized. This time depends on the rare-earth composing the garnet phase and on the annealing temperature. 相似文献