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1.
Designs, Codes and Cryptography - According to a magnific method due to I. Tamo and A. Barg, a class of polynomials over finite fields, called good polynomials, was introduced and used to construct...  相似文献   
2.
Inspired by the intriguing structures and remarkable activities of sesquiterpenoid dimers,12 new sesquiterpenoid dimers,artematrovirenolides A—D(1—4)and artematrolides S—Z(8—12),were isolated from the EtOAc fraction of Artemisia atrovirens through a bioactivity-guided approach.Their structures were elucidated by comprehensive spectroscopic data and absolute configuration was assigned based on single crystal X-ray diffraction data and ECD calculations.Structurally,all compounds are presumably formed via[4+2]cycloaddition involving three connecting model.Compounds 1—4 are four novel hetero-dimeric[4+2]Diels-Alder adducts dimerized from a rotundane-type unit and a guaiane-type monomer,and compounds 5—12 are eight new homo-dimeric[4+2]adducts derived from two guaianolide moieties.A putative biosynthetic pathway for compounds 1—4 was also proposed.Compounds 4,6,7,and 10 demonstrated moderate cytotoxicity against HepG2,SMMC-7721,and Huh7 cell lines with IC50 values ranging from 9.3 to 62.3μmol/L.Interestingly,compounds 5 and 11 manifested cytotoxicity with IC50 values of 13.6 and 12.8(HepG2),18.5 and 13.1(SMMC-7721),and 16.5 and 19.4μmol/L(Huh7),respectively,which were equivalent to the positive control,sorafenib.This investigation suggests that compounds 5 and 11 might be considered as potent antihepatoma candidates and deserve further structural modification and mechanism study.  相似文献   
3.
在水热条件下,合成了1个新的双核锌配合物[(ZnCl2)(PyBIm)]2(PyBIm=2-(4-pyridyl)benzimidazole)。该配合物为单斜晶系,P21/n空间群,晶胞参数a=0.774 51(4) nm,b=1.252 49(5) nm,c=1.315 96(7) nm,β=100.294(3)°,V=1.256 0(1) nm3,Z=2。结构分析表明,Zn被2个Cl原子和来自PyBIm配体的2个N原子配位,形成了1个变形四面体结构。在该配合物中,Zn…Zn距离为 0.709 4(5) nm,结构中存在π…π堆积和氢键作用。  相似文献   
4.
通过在同位旋相关量子分子动力学模型(IQMD)中引入同位旋依赖的动量相关作用和同位旋相关的Skyrme势,得到了改进的同位旋依赖的量子分子动力学模型,并用此模型分析和讨论了中能重离子碰撞中的同位旋分馏强度随入射道条件的演化.结果表明在中能重离子碰撞中各种入射道条件下同位旋依赖的动量相关作用和Skyrme势有着明显的同位旋效应,它们减弱了同位旋分馏的过程. 关键词: 同位旋分馏 同位旋相关的动量相关作用 同位旋相关的Skyrme势  相似文献   
5.
张永平  孙伟华  刘长安 《中国物理 B》2010,19(5):50512-050512
A visualization of Julia sets of the complex Henon map system with two complex variables is introduced in this paper.With this method,the optimal control function method is introduced to this system and the control and synchronization of its Julia sets are achieved.Control and synchronization of generalized Julia sets are also achieved with this optimal control method.The simulations illustrate the efficacy of this method.  相似文献   
6.
A numerical model for bilayer organic light-emitting diodes (OLEDs) has been developed on the basis of trappedcharge limited conduction. The dependences of the current density on the operation voltage, the thickness andtrap properties of the hole transport layer (HTL) and emission layer (EML) in bilayer OLEDs of the structure an-ode/HTL/EML/cathode have been numerically investigated. It has been found that, for given values of reduced trapdepth, total trap density, and carrier mobility of HTL and EML, there exists an optimum thickness ratio of HTL tothe sum of HTL and EML, by which a maximal current density, and hence maximal quantum efficiency and luminance,can be achieved. The current density decreases quickly with the mean trap density, and decreases nearly exponentiallywith the mean reduced trap depth.  相似文献   
7.
本文采用密度泛函理论方法,研究了氢气分子在硼取代富勒烯C19Bn+(n=0-3)表面的非解离吸附态、化学吸附态、及吸附态之间转换过渡态的结构和能量,得到了吸附态之间转换反应的势能面. 研究表明通过调整体系的离子化电荷可以调整吸附位点的电荷布居数,随着硼取代富勒烯离子化体系C19Bn+的吸氢活性位点电荷布居数增大,氢分子被极化的程度以及氢分子在材料表面的吸附能均逐渐增大,同时改变电荷布居数也对氢气分子在表面吸附态间转变势垒高度产生了量级为几个Kcal/mol的影响. 希望我们的研究能够对富勒烯储氢的进一步发展提供参考.  相似文献   
8.
采用溶胶-燃烧法合成了可用于固体氧化物燃料电池(SOFC)的新型固体电解质材料CaZr0.1Ti0.9O3。通过XRD、交流复阻抗等电化学方法对样品的结构、电导性能进行了表征,并考察了材料的烧结性能。结果表明,溶胶-燃烧法可以成功制备出具有良好烧结性能的CaZr0.1Ti0.9O3电解质粉末,1400℃下得到的烧结体的相对密度可达到95%。电性能测试表明CaZr0.1Ti0.9O3烧结体在中温范围内具有较高的氧离子电导率(σ800℃=2.24×10-3 S/cm)、低的电导活化能(0.89 eV);样品的导电性能受烧结温度的影响,合理的控制烧结温度对于获得导电性能优良的CaZr0.1Ti0.9O3电解质材料具有重要作用。  相似文献   
9.
A novel cadmium coordination polymer [Cdls(OH)4(SO4)4(L1)6(L2)12]n (HL1 = 1,2,3-1H-triazole, HL2 = 5-methyl-lH-tetrazole) has been synthesized and characterized by elemental analysis and single-crystal X-ray diffraction. The compound crystallizes in cubicI-43d space group with a = 21.5247(4), V = 9972.7(3) A3, Z = 4, Dc = 2.360 g/cm3, Mr = 3543.68, μ(MoKα) = 3.298 mm^-1, F(000) = 6696, the final R = 0.0340 and wR = 0.0992 for 1909 observed reflections (I 〉 2σ(I)). The compound contains two crystallographicatly independent Cd coordination centers linked up through one L1 and two L2 bridges. The structure displays an inorganic-organic hybrid cadmium coordination polymer.  相似文献   
10.
A class of shock-capturing Petrov–Galerkin finite element methods that use high-order non-oscillatory interpolations is presented for the one-dimensional compressible Euler equations. Modified eigenvalues which employ total variation diminishing (TVD), total variation bounded (TVB) and essentially non-oscillatory (ENO) mechanisms are introduced into the weighting functions. A one-pass Euler explicit transient algorithm with lumped mass matrix is used to integrate the equations. Numerical experiments with Burgers' equation, the Riemann problem and the two-blast-wave interaction problem are presented. Results indicate that accurate solutions in smooth regions and sharp and non-oscillatory solutions at discontinuities are obtainable even for strong shocks.  相似文献   
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