基数排序的非链式分配算法

本文提出了没有指针数据类型的程序设计语言中进行基数排序的基本思想,讨论了在微机上实现基数排序的算法,并把“分配”和“收集”合为一步进行,最后分析了时间和空间的复杂度。     

数学定理的抽象度

徐利治和张鸿庆在中提出了数学抽象度概念和抽象度分析法，这种分析法可以用于数学领域的各个分支，用来分析各种数学问题，本文研究如何给出数学定理的抽象度。     

关于李世荣的一个定理

本文使用文献[1]的结果,证明了下列定理:定理设G为有限群。假若G的非正规极大子群同阶类类数=2,则(1)若G可解,则|π(r_∞(G))|≤2。(2)若G不可解,则其中Z_2~3为G′φ(G)的极小正规子群,K可解,i=0,1,2,……     

加权复合算子在两类函数空间之间的序有界性北大核心CSCD

本文首先研究了加权复合算子W_(Φ,φ)(f):=Φfoφ的Hilbert-Schmidt性质与序有界性的对应关系.接着利用加权Dirichlet空间D^(q)_(β)(0相似文献   

Texture and Optical Studies of the Mesophases of Cyanocyclohexyl Cyclohexanes

Optical studies have been conducted as a function of temperature on two (CCH₃ and CCH₇) of the three odd members of the homologous series of the mesogen trans, trans-4′-alkyl-bicyclohexyl-4-carbonitrite. From birefringence studies the variation of the orientational order parameter ? P₂ ? with temperature of the two members has been determined. Texture studies have been conducted to identify hitherto unidentified phases. A comparative study of the temperature dependence of the refractive indices n _e, n _o , and ? P₂ ? of all the three members CCH₃, CCH₅, CCH₇ have been presented with a view to study the effect of increasing chain length. Comparison of the experimentally obtained ? P₂ ? values has been made with theoretical values predicted by the Maier-Saupe theory.     

Influence of Defects on First Order Structural Phase Transitions

The influence both of symmetry-breaking ("random local field") defects and of symmetry conserving ("random local transition temperature") ones on first order phase transitions is studied within the Landau theory. It is shown that an explicit account, for the elasticity effects, is important in the case of symmetry-breaking defects: the discontinuity of the order parameter at the transition increases due to the defects when the elasticity effects are taken into account but it decreases when they are neglected. For the symmetry-conserving defects, the account for the elasticity does not change the results qualitatively: the defects always diminish the discontinuity of the order parameter. The phase transition temperature always decreases due to the randomness induced by the two types of defects.     

Phase transformations in calcite from electrical impedance measurements

The phase transformation in calcite I-IV-V and calcite ? aragonite have been characterized by electrical impedance measurements at temperatures 600–1200°C and pressures 0.5–2.5?GPa in a piston cylinder apparatus. The bulk conductivity σ has been measured from Argand plots in the frequency range 10⁵–10^?2?Hz in an electric cell representing a coaxial cylindrical capacitor. The synthetic polycrystalline powder of CaCO₃ and natural crystals of calcite were used as starting materials. The transformation temperature T_c was identified from resistivity-temperature curves as a kink point of the activation energy. At pressure above 2?GPa in ordered phase calcite I, the activation energy E _σ is c. 1.05?eV, and in disordered phase calcite V E _σ is c. 0.75?eV. The pressure dependence of T_c for the rotational order–disorder transformation in calcite is positive for pressures <1?GPa and negative for pressures >1?GPa. The transformation boundary of calcite 1–IV is observed only during first heating in samples after a long annealing at low temperatures. The activation energy of calcite I???IV decreases gradually from 1.8 to 1.05?eV with the pressure increase from 0.5 to 2?GPa. The kinetics of calcite ? aragonite transformation has been monitored by measuring a time-variation of the electrical resistance of a calcite sample at 10³?Hz in the stability P-T field of aragonite. The variation of the impedance correlates with the degree of phase transformation, estimated from X-ray powder diffraction studies on quenched products of experiments. The kinetics of calcite ? aragonite transformation may be fitted to the Avrami kinetics with the exponent m???1–1.5.     

均匀腐蚀下管道可靠度及参数敏感度研究

分别采用一次二阶矩法和Monte-Carlo法对某存在均匀腐蚀的管道进行了可靠性分析,结果发现Monte-Carlo方法分析结果可靠度数值略低于一次二阶矩法;可靠性分析发现,虽然管道的平均应力始终小于屈服应力,但管道可靠度随着均匀腐蚀的发生呈现加速下降趋势,至运行20年可靠度仅为0.58,已经无法安全使用;管道可靠性参数分析发现,对管道可靠度影响最大的为壁厚,其次为材料强度性能,然后为材料的载荷状况,材料载荷对可靠度的影响程度取决于这种载荷对管道总体应力的贡献程度。     

33阶Steiner三连系及67阶Steiner三连系的构造

给出了“边矩阵”及“完全三分图”的定义,为了构造v=2t 1阶Steiner三连系,提出了基于图论理论的构造思路,证明了2t 1阶Steiner三连系的存在和构造的定理。介绍了33阶Steiner三连系和67阶Stein- er三连系的构作和计数。     

Observation of broken time-reversal symmetry with Andreev bound state tunneling spectroscopy

Quasiparticle (QP) planar tunneling spectroscopy is used to investigate the density of states (DoS) of YBa₂Cu₃O₇ (YBCO). Temperature, crystallographic orientation, doping, damage and magnetic field dependencies confirm that the observed zero-bias conductance peak (ZBCP) is an Andreev bound state (ABS), an intrinsic property of a d-wave superconducting order parameter (OP) at an interface. In zero applied field, the splitting of the ZBCP below 8 K confirms a near-surface phase transition into a superconducting state with spontaneously broken time-reversal symmetry (BTRS). Tunneling into the ABS provides a phase-sensitive spectroscopy that can be used to measure a variety of DoS properties in an unconventional superconductor.