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991.
研究了采用单点金刚石超精密车削加工技术(SPDT)加工多模调制曲面过程中的刀具轨迹优化方法,首先,分析了SPDT方法加工多模调制曲面的基本原理;其次,理论分析了平行弦双圆弧插补算法的基本原理,推导了插补误差计算公式。在此基础上,提出采用插补步长伸缩变化方式实现了插补误差的动态控制,并获得了完整的插补计算公式;最后,采用Matlab软件对该插补算法进行了实例仿真分析,并分别与直线插补算法和固定步长双圆弧插补算法进行了对比分析,结果表明,该方法能在保证插补允差的前提下最大程度的减少插补区间数,从而有助于提高加工效率和延长刀具寿命。该方法在调制靶金属模板的制备中获得了广泛应用。 相似文献
992.
平面八节点四边形理性元 总被引:2,自引:0,他引:2
推导平面八节点四边形理性有限元列式,采用具有直到四次多项式的平面问题的微分方程的解作为插值函数,算例结果表明平面八节点四边形理性有限元的有效性. 相似文献
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996.
Young-Woon Cho Kyung-Seok Kang Chanhyuk Jee Ji-Hyun Kim Dongju Jang 《Molecular Crystals and Liquid Crystals》2016,634(1):73-81
Polyamic acid (PAA) made from 3,3, 4,4-biphenyltetracarboxylic dianhydride and 4,4-diaminodiphenyl ether was synthesized and used as the backbone of nanoporous polyimide. Thermally labile polyethylene glycol (PEG) at 10, 20 or 30 wt% was introduced to the end group of PAA. Self-assembled PAA-b-PEG micelle-like nanoparticles could be formed as a result of amphiphilic characteristics of hydrophobic PAA and hydrophilic PEG. Thermal imidization and degradation of spin-coated amphiphilic PAA-b-PEG film were performed sequentially through one-step heat treatment to obtain polyimide film with nanopores. Pore sizes decreased with increasing amount of PEG block and their dielectric constants decreased from 2.71 ± 0.13 to 2.38 ± 0.11. 相似文献
997.
Sompong Dhompongsa Anchalee Kaewcharoen Attapol Kaewkhao 《Nonlinear Analysis: Theory, Methods & Applications》2006
Let E be a nonempty bounded closed convex separable subset of a reflexive Banach space X which satisfies the Domínguez–Lorenzo condition, i.e., an inequality concerning the asymptotic radius of a sequence and the Chebyshev radius of its asymptotic center. We prove that a multivalued nonexpansive mapping T:E→2X which is compact convex valued and such that T(E) is bounded and satisfies an inwardness condition has a fixed point. As a consequence, we obtain a fixed-point theorem for multivalued nonexpansive mappings in uniformly nonsquare Banach spaces which satisfy the property WORTH, extending a known result for the case of nonexpansive single-valued mappings. We also prove a common fixed point theorem for two nonexpansive commuting mappings t:E→E and T:E→KC(E) (where KC(E) denotes the class of all compact convex subsets of E) when X is a uniformly convex Banach space. 相似文献
998.
Carl Boor 《Advances in Computational Mathematics》2006,24(1-4):143-153
A lemma of Micchelli's, concerning radial polynomials and weighted sums of point evaluations, is shown to hold for arbitrary
linear functionals, as is Schaback's more recent extension of this lemma and Schaback's result concerning interpolation by
radial polynomials. Schaback's interpolant is explored.
Happy 60th and beyond, Charlie!
Mathematics subject classifications (2000) 41A05, 41A6. 相似文献
999.
The bulk crystal of LiSrBO3 (8.39 g) with a size of 21mm×20mm×15mm was grown by high temperature solution growth method. The relationship between growth habit and crystal structure was discussed. The transmission spectrum shows an UV absorption edge at about 300 nm. The melting temperature of this crystal was determined to be 942 ℃ by DTA-TG measurement. The band structure of the LiSrBO3 crystal was studied by means of the first principle method. An indirect band gap was found to be about 4.0 eV,and a low dielectric constant was estimated to be about 1.9 in terms of theoretical results. 相似文献
1000.
Schiff base N,N′-bis(salicylidene)-p-phenylenediamine (LH2) complexed with Pt(en)Cl2 and Pd(en)Cl2 provided [Pt(en)L]2 · 4PF6 (1) and Pd(Salen) (2) (Salen = N,N′-bis(salicylidene)-ethylenediamine), respectively, which were characterized by their elemental analysis, spectroscopic data and X-ray data. A solid complex obtained by the reaction of hexafluorobenzene (hfb) with the representative complex 1 has been isolated and characterized as 3 (1 · hfb) using UV–Vis, NMR (1H, 13C and 19F) data. A solid complex of hfb with a reported Zn-cyclophane 4 has also been prepared and characterized 5 (4 · hfb) for comparison with complex 3. The association of hfb with 1 and 4 has also been monitored using UV–Vis and luminescence data. 相似文献