扩张原理的粗集表示

粗集、模糊集均是处理不确定信息的数据分析工具,是数据挖掘的重要方法.由Zadeh首先提出的模糊扩张原理是模糊集理论的最基本的原理之一,粗集是通过上、下近似算子来发挥作用的.本文讨论扩张原理与粗集上近似之间的关系,证明了扩张原理可以表示成粗集上近似的形式,因此,扩张原理成了粗集与模糊集之间的桥梁.此外,借助粗集上、下近似算子的公理系统解决了扩张原理的反问题.     

新的Schiff碱-双(2,3-二甲氧基苯甲醛)缩联苯胺的合成与光谱研究

以2,3-二甲氧基苯甲醛和联苯胺为原料,在无水甲醇溶剂中合成了一种新的Schiff碱,收率为86.0%.反应的最佳条件是2,3-二甲氧基苯甲醛与联苯胺的比例为3:1,反应时间为1h,反应温度为30℃.这种新的Schiff碱结构利用IR和UV光谱表征.     

Modeling of failure characteristics of rectangular hard rock influenced by sample height-to-width ratios: A finite/discrete element approach

In the present study, a combined finite/element approach is used to analyze failure characteristics of a rectangular hard rock with different sample height-to-width ratios based on the uniaxial compression test. The objective of this paper is to illustrate the transitional mechanisms from shear fracture to extension failure of brittle rocks and the occurrence conditions of surface-parallel slabbing. Numerical results show that failure modes have experienced the shear, tension with shear and surface-parallel slabbing failure with the decrease of sample height-to-width ratios. It is seen from the simulation results that the shear band in larger height-to-width ratios is composed of an amount of extension meso-cracks that are parallel to the loading direction, and the slabbing failure tends to be the result of the accessible propagation of extension meso-cracks due to short sample height, which validate the essence of extension failure in hard rocks. The good agreement between simulation and laboratory testing also shows the practicability and advancement of a combined finite/discrete element approach.     

可拓神经网络模式识别对成品油的鉴别与测量

燃油存在“消耗量大”、“相对低质”、“前端缺少清洁”、“末端排放缺乏控制”四大问题, 我国的空气污染60%以上来自煤和油的燃烧,雾霾问题很大程度上取决于能源问题。快速准确地实现汽油、柴油、煤油等成品油的鉴别与测量,对于实施空气污染监测及治理具有重要意义。在精确地表征成品油种类信息的基础上,为了提高网络模型的识别效率,采用主成分分析方法将高维空间进行降维处理。对最常用的三维荧光光谱基于激发-发射矩阵(excitation-emission matrix, EEM)数据进行主成分分析以提取更精细、更深层的特征参量。分类过程中应用交叉验证的方法避免发生“过拟合”现象。设计鉴别和测量双重处理的神经网络,将神经网络模式识别结果反馈到浓度网络的输入端,与相对斜率、综合本底参数、相对荧光强度一起测量相应种类的浓度输出,利用可拓神经网络模式识别技术实现成品油的鉴别与测量。应用可拓神经网络方法实现成品油种类模式识别的平均识别率达到0.99,浓度平均回收率为0.95。模式识别平均耗时为2.5 s,仅为PARAFAC模型分析方法的48.5%。该方法显著提高了运算速度,且应用效果理想。需要指出的是,在分析诸如成品油、茶叶、农药等成分复杂的混合物时,应针对具体待测物制作相应的校正样本,用以确保分析的准确性与精度。     

Steady flow past a torus with aspect ratio less than 5

Steady flow past a torus with an aspect ratio less than 5 and its axis aligned with the flow is studied numerically by solving the steady, axisymmetric Navier–Stokes equations. The wake structure behind tori exhibits diverse behaviours. The detached recirculating zone on the axis, the attached recirculating zone, and the detached recirculating zone behind the torus tube may appear individually or concurrently, depending on the aspect ratio and the Reynolds number. A wake structure map is summarized based on the observed flow behaviours. Six flow regimes with different wake behaviours are identified and the corresponding flow regime map is plotted, which include the no-recirculating-zone regime, the single-detached-recirculating-zone regime, the single-attached-recirculating-zone regime, the two-recirculating-zone regime I, the two-recirculating-zone regime II, and the three-recirculating-zone regime. Over the range of aspect ratio 1.9<AR<2.4, the detached wake initially increases but then decreases in size with Reynolds number, and eventually disappears at Reynolds numbers beyond a critical value (depending on the aspect ratio). The underlying mechanisms of the onset and disappearance of the recirculating zones are discussed in terms of vorticity accumulation and base bleed. The recirculating zone first occurs when the maximum vorticity on the surface of the torus exceeds about 5. The detached recirculating zone on the axis of the torus disappears once the flow rate through the hole of the torus is beyond a certain threshold. In addition, the present results suggest that different transition modes to non-axisymmetric flow for tori with different aspect ratios reported in the literature may result from the wake structures prior to the transition.     

基于可拓变换的商业模式创新研究——以电动汽车商业模式创新为例

商业模式创新是企业本源的创新,是企业一切创新活动的基础和盈利的保障.目前,学术界和实业界对于商业模式创新仍然缺乏有效的方法和工具,在回顾商业模式相关文献的基础上,以电动汽车产业的商业模式创新为例,通过基元理论和可拓变换理论建立了流程化、形式化的商业模式创新方法.研究不仅丰富了商业模式理论,为商业模式创新提供了新的方法,同时对于丰富完善管理可拓工程理论也具有重要的意义.     

Asymmetric Schiff Base (N 2 O 3 ) Complexes as Ligands Towards Mn(II), Fe(III) and Co(II), Synthesis and Characterization

Heterobi- and tri-nuclear complexes [LMM'Cl] and [(LM) 2 M'](M=Ni or Cu and M'=Mn, Fe or Co) have been synthesised. The heteronuclear complexes were prepared by stepwise reactions using two mononuclear Ni(II) and Cu(II) complexes of the general formula [HLM]·1/2H 2 O, as ligands towards the metal ions, Mn(II), Fe(III) and Co(II). The asymmetrical pentadentate (N 2 O 3 ) Schiff-base ligands used were prepared by condensing acetoacetylphenol and ethylenediamine, molar ratio 1 1, to yield a half-unit compound which was further condensed with either salicylaldehyde or naphthaldehyde to yield the ligands H 3 L 1 and H 3 L 2 which possess two dissimilar coordination sites, an inner four-coordinate N 2 O 2 donor set and an outer three-coordinated O 2 O set. 1 H NMR and IR spectra indicate that the Ni(II) and Cu(II) ions are bonded to the inner N 2 O 2 sites of the ligands leaving their outer O 2 O sites vacant for further coordination. Different types of products were obtained according to the type of metal ion. These products differ in stoichiometry according to the type of ligand in the parent compound. Electronic spectra and magnetic moments indicate that the structures of the parent Ni(II) and Cu(II) complexes are square-planar while the geometry around Fe(III), Mn(II) and Co(II) in their products are octahedral as elucidated from IR, UV-visible, ESR, 1 H NMR, mass spectrometry and magnetic moments.     

Complex Salts Derived from the Reactions of Organotin(IV) with 6-Methylpyridine-2-Carboxaldehyde Phenylhydrazone: X-Ray Crystal Structure of BIS[6-Methylpyridine- 2-Carboxaldehydehydrazodium]- Tetrachlorodimethylstannate(IV)

Reactions of organotin(IV) chloride (Me 2 SnCl 2 , PhSnCl 3 and n -BuSnCl 3 ) with the Schiff base 6-methylpyridine-2-carboxaldehyde phenylhydrazone ( L ) result in the formation of organotin(IV) anionic complexes. Me 2 SnCl 2 reacts with L in dichloromethane to form [ L H + ] 2 [Me 2 SnCl 4 ] 2 m . X-ray structural analysis has been carried out on the complex salt bis[6-methylpyridine-2-carboxaldehydehydrazodium]tetra-chlorodimethylstannate(IV), [ L H + ] 2 [Me 2 SnCl 4 ] 2 m wherein the tin moieties exist as monomers. Reactions of PhSnC1 3 and n -BuSnCl 3 with L form the complexes [ L H + ] 2 [PhSnCl 5 ] 2 m and [ L H + ] 2 [ n- BuSnCl 5 ] 2 m . Compounds were also characterized by FTIR, 1 H and 13 C NMR spectroscopy.     

J-semicommutative环的性质

环冗称为J—semicommutative若对任意B,b∈R由ab=0可以推得aRb∈J（R）,这里J（R）是环R的Jacobson根．环R是J—semicommutative环当且仅当它的平凡扩张是J—semicommutative环当且仅当它的Don＇oh扩张是J—semicommutative环当且仅当它的Nagata扩张是,一semicommutative环当且仅当它的幂级数环是J—semicommutative环．若R／J（R）是semicommutative环,则可得到R是J-semicommutative环．本文进一步论证了如果,是环月的一个幂零理想,且R／I是J—semicommutative环,则R也是J-semicommutative环最后给出了J—semicommutative环与其他一些常见环的联系     

Base force element method of complementary energy principle for large rotation problems

Using the concept of the base forces, a new finite element method （base force element method, BFEM） based on the complementary energy principle is presented for accurate modeling of structures with large displacements and large rotations. First, the complementary energy of an element is described by taking the base forces as state variables, and is then separated into deformation and rotation parts for the case of large deformation. Second, the control equations of the BFEM based on the complementary energy principle are derived using the Lagrange multiplier method. Nonlinear procedure of the BFEM is then developed. Finally, several examples are analyzed to illustrate the reliability and accuracy of the BFEM.