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61.
Sławomir Rams 《manuscripta mathematica》2003,111(1):29-41
We study the geometry and codes of quartic surfaces with many cusps. We apply Gr?bner bases to find examples of various configurations
of cusps on quartics.
Received: 10 May 2002 / Revised version: 11 November 2002
Published online: 3 March 2003
Permanent address: Institute of Mathematics, Jagiellonian University, ul. Reymonta 4, 30-059 Kraków, Poland. e-mail: rams@mi.uni-erlangen.de,
rams@im.uj.edu.pl
Research partially supported by the Schwerpunktprogramm ``Global methods in complex geometry' of the Deutsche Forschungsgemeinschaft,
and by EAGER.
Mathematics Subject Classification (2000): 14J25, 14J17 相似文献
62.
Phenylene vinylene‐based electroluminescent polymers with electron transport block in the main chain
Honghao Sun Chongyu Mei Quanguo Zhou Ze Liu Dongge Ma Lixiang Wang Xiabin Jing Fosong Wang 《Journal of polymer science. Part A, Polymer chemistry》2006,44(11):3469-3478
We report a new route for the design of soluble phenylene vinylene (PV) based electroluminescent polymers bearing electron‐deficient oxadizole (OXD) and triazole (TZ) moieties in the main chains with the aryloxy linkage. Both series of the PV‐based polymers were prepared by Wittig reaction. By properly adjusting the OXD and/or TZ content through copolymerization, we can achieve an enhanced balance of hole‐ and electron injections, such that the device efficiency is significantly improved. Light‐emitting diodes fabricated from P1, P2, P3, P4, P5, P6, and P7 with the configuration of Indium–Tin Oxide (ITO)/Poly (styrene sulfonic acid) doped poly (ethylenedioxythiophene) (PEDOT)/polymer/Ca/Al, emit bright green light with the maximum peak around 500 nm. For the device using the optimal polymer (P4) as emitting layer, a maximum brightness of 1300 cd/m2 at 20 V and a maximum luminance efficiency of 0.325 cd/A can be obtained. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 3469–3478, 2006 相似文献
63.
64.
Zhicheng Xiao Ying Li Dongling Ma Linda S. Schadler Yvonne A. Akpalu 《Journal of Polymer Science.Polymer Physics》2006,44(7):1084-1095
Small‐angle light scattering (SALS) measurements were used to study the structure of titanium dioxide (TiO2)/low‐density polyethylene (LDPE) nanocomposites. The results showed that the scattering from LDPE crystalline structures and the scattering from TiO2 nanoparticles can be resolved and separated. It is shown that the independent effects of crystallization conditions and the presence of nanoparticle aggregates on the spherulitic structure of the LDPE matrix can be determined by analyzing the scattering patterns using the methods proposed. From the SALS results, we conclude that the nanoparticle surface chemistry affects both nucleation of spherulites and their structure particularly under rapid cooling conditions. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 1084–1095, 2006 相似文献
65.
We study the existence of positive solutions to the operator equation Lx = Nx, where L is a linear Fredholm mapping of index zero and N is a nonlinear operator. Using the properties of cones in Banach spaces and Leray-Schauder degree for completely continuous
operators, k-set contractions and condensing mappings, we obtain some refinements of the results established in [3] and [14].
Received: 9 July 2005; revised: 12 January 2006 相似文献
66.
物理插图能起到形象地再现物理情景,辅助解释物理原理的作用.现行人教版物理第二册(必修加选修),第十章“机械波”第一节的知识“波的形成和传播”是该章的重点,本节插图10-5“横波的形成”又是该节的教学重点.这幅插图用得好,直接为后面的波的图像教学及用图像解决问题打下坚实的基础. 相似文献
67.
Wang Binglin Ma Shiming Chian Jian Zong Huiqi Tang Quanyong 《Radiation Physics and Chemistry》1998,52(1-6):439-442
The radiation facility was made by Sulzer Company in Switzerland. The designed capacity is 3.7 × 1016Bq( 1MCi) and 12.21 × 1015Bq(330kCi)of Cobalt -60 source was loaded at the first phase. Current cobalt -60 source-loading is 2.4 × 1016Bq(650kCi). The equipment assembling and installation regulating and testing were completed at the end of 1988. The facility was put into commissioning in 1989. It operates 7000–8000 hours per year. The facility has been utilized to carry out many research work and irradiate many kinds of items. Lots of economical benefits have been gained since then. Now it is becoming a radiation processing model base in China. This paper summarized the strong and weak points of the design of the facility through in eight years' practice and analysed the economical benefits. 相似文献
68.
激光感生碰撞能量转移的四能级理论模型 总被引:6,自引:2,他引:4
首次考虑了两个中间态对激光感生碰撞能量转移的影响,发展了激光感生碰撞能量转移的四能级理论模型,推导出态振幅的运动方程,并给出碰撞截面的近似表达式,通过对Eu-Sr和Cs-Sr系统的数值计算表明,当频率差│ω21│大小和│ω43│可以相比时,利用三能级近似理论就难以获得令人满意的计算结果,而四能级理论模型则适合于任何情况下的激光感生碰能量转移。 相似文献
69.
Let (E, ¦·¦) be a uniformly convex Banach space with the modulus of uniform convexity of power type. Let be the convolution of the distribution of a random series inE with independent one-dimensional components and an arbitrary probability measure onE. Under some assumptions about the components and the smoothness of the norm we show that there exists a constant such that |{·<t}–{·+r<t}|r
q
, whereq depends on the properties of the norm. We specify it in the case ofL
spaces, >1. 相似文献
70.
Paweł Grochulski Zdzisław Wawrzak Zdzisław Gałdecki Antoinette Viger Suzy Coustal 《Journal of chemical crystallography》1990,20(5):429-432
The crystal structure of 18-cyanoprogesterone was determined by X-ray diffraction methods:P212121
a=7.436(2),b=11.322(2),c=22.642(2) Å. The structure was solved usingShelx-86. Final conventionalR=0.054.R
w
=0.051 for 1841 reflections. TheA ring has an intermediate sofa-half-chair conformation with asymmetry parameters C
s
/1
=11.0, C
2
3,4
=14.9. The steroid skeleton exhibits a flattening of theA ring relative to the rest of the molecule. The progesterone side chain has a typical conformation, and the C16-C17-C20-O20 torsion angle is –19.0(6)°. 相似文献