Deformation Techniques for Sparse Systems

We exhibit a probabilistic symbolic algorithm for solving zero-dimensional sparse systems. Our algorithm combines a symbolic homotopy procedure, based on a flat deformation of a certain morphism of affine varieties, with the polyhedral deformation of Huber and Sturmfels. The complexity of our algorithm is cubic in the size of the combinatorial structure of the input system. This size is mainly represented by the cardinality and mixed volume of Newton polytopes of the input polynomials and an arithmetic analogue of the mixed volume associated to the deformations under consideration. Research was partially supported by the following grants: UBACyT X112 (2004–2007), UBACyT X847 (2006–2009), PIP CONICET 2461, PIP CONICET 5852/05, ANPCyT PICT 2005 17-33018, UNGS 30/3005, MTM2004-01167 (2004–2007), MTM2007-62799 and CIC 2007–2008.     

有界对称域的特征

We give a necessary and sufficient condition for a domain to be biholomorphic to a bounded symmetric domain.     

Volumetric, Electric, and Magnetic Properties of Thioxanthen-9-one in Aprotic Solvents as Revealed by High-Precision Densitometry, High-Accuracy Refractometry and Magnetic Susceptibility Measurements and by DFT Calculations

High-precision densitometry measurements of solutions of thioxanten-9-one (TX) in 1,4-dioxane, DMSO, toluene, and benzene have been obtained at 293.15, 303.15, 313.15, 323.15, 333.15, and 343.15K. The partial molar volumes of TX ( ) and the corresponding values at infinite dilution ( ) were determined. The partial molar expansibility ( ) of TX at infinite dilution in each solvent is temperature independent. Dynamic electronic polarizabilities of TX in each aprotic solvent were determined by the Singer–Garito approach. These values are in excellent concordance with the theoretical value for TX of 2.611×10⁻²³cm³ estimated here using DFT/B3LYP/6-311++G(d,p). The partial molar volumes of TX at infinite dilution were calculated and interpreted in terms of the Scale Particle Theory (SPT). The solvent influence on the partial molar volume of TX was found to be due mainly to cavity formation and intermolecular dispersion forces.     

Densities and Volumetric Properties of Binary Mixtures of Tetrahydrofuran with Some Aromatic Hydrocarbons at Temperatures from 278.15 to 318.15 K

The densities, ρ, of binary mixtures of tetrahydrofuran (THF) with benzene, toluene, o-xylene, m-xylene, p-xylene and mesitylene, including those of the pure liquids, were measured over the entire composition range at the temperatures (278.15, 283.15, 288.15, 293.15, 298.15, 303.15, 308.15, 313.15 and 318.15) K and atmospheric pressure. From the experimental data, the excess molar volume, V _m ^E, partial molar volumes, _m,1 ^∘ and _m,2 ^∘, and excess partial molar volumes, _m,1 ^∘E and _m,2 ^∘E, at infinite dilution were calculated. The V _m ^E values were found to be negative over the whole composition range for all of the mixtures and at each temperature studied, except for THF + mesitylene, which exhibits a sigmoid trend wherein V _m ^E changes sign from negative to positive as the concentration of THF in the mixture is increased, indicating the presence of specific interactions between THF and aromatic hydrocarbon molecules. The extent of negative deviations in the V _m ^E values follows the order: benzene > toluene > p-xylene > m-xylene > o-xylene > mesitylene. It is observed that the V _m ^E values depend upon the number and position of the methyl groups in these aromatic hydrocarbons.     

固体材料中原子核外价电子能态变化研究

研究了改变材料中价电子能态的方式问题,结果表明,温度、材料体积、外场和掺杂是改变材料内价电子能态的四种方式,指出,材料体积对价电子能态的影响主要表现在0 K时能带的形成;温度和外场对价电子能态的影响,主要体现在对价电子轨道运动能量的影响上;掺杂改变了晶格势场的分布,从而改变了价电子在晶格势场中的电势能,改变了价电子的能态.     

龙虎泡低渗透油田聚表二元复合驱实验研究

针对龙虎泡低渗透油田水驱开发效果差、采收率低等特点,开展了聚合物和表面活性剂二元复合驱在低渗透油藏适应性的室内评价实验.注入性实验表明,相对分子量为2 200万的FP-3聚合物注入渗透率46.45×10-3μm2的岩心未发生堵塞,具有良好的注入选择性及封堵选择性.驱油实验表明,聚合物和表面活性剂可分别提高低渗透岩心驱油效率10%和20%,且表面活性剂容易注入,可降低注入压力.在聚合物和表面活性剂不同段塞组合实验中,两者分段塞注入的方式优于单独注入表面活性剂或将两者混合后注入的方式,其中先注聚合物后注入表面活性剂的段塞组合方式最好,可提高采收率17.74%.因此,对于非均质性较弱的低渗透油田,可采用聚表二元复合驱技术,先注入聚合物降低储层的非均质性,后注入表面活性剂启动低渗区的剩余油.     

油藏分块数据组织与快速展示技术

利用三维可视化方式展示大型油藏需要耗费较长时间。针对此问题,引入"分块数据组织"的概念,设计油藏数据体分割与油藏分块数据组织的模式。结合Open Inventor设计并实现基于单个块体的油藏演变过程动态展示的功能,以油藏块体为基本单元,将油藏展示的任务分解成若干个块体展示的任务,提出油藏并行展示的方法。胜利油田埕岛区块和江苏油田陈堡区块的油藏展示结果表明,基于数据体分割、分块组织数据、并行展示等技术可以有效提高大型油藏展示的效率。     

郑州市自来水销售量预测研究

通过分析郑州市2006-2009年的自来水销售量,建立了郑州市自来水销售量的灰色模型GM（1,1）,并预测了今后几年郑州市的自来水销售量。     

盗伐、滥伐林木材积测算及定案研究

盗伐、滥伐林木材积数量是对案件定性、对行为人处罚的重要依据。目前材积测算的方法较多,相关法律法规对测算方法没有统一规定,导致同一案件出现多个测算结果。笔者采用案例研究、调查访问、模拟现场调查等方法,根据涉案林木的状态,分别对几种常用的测算方法的精度进行了比较研究,提出应根据不同案情确定材积测算方法;同一案情有多种测算方法时,应优先选用精度较高的方法,使测算结果具有唯一性,并经司法机关认可取得合法性。这样对盗伐、滥伐林木案件进行定案时可减少争议的出现,缩短办案时间,提高办理毁林案件的质量。     

立方格子导电球的有效介电常数的频率依赖性

利用Maxwell-Wagner模型,同时采用John Lam在磁流变体中研究磁导率的迭代方法,研究了电流变体中3种结构的立方格子导电球的有效介电常数与频率的依赖关系.结果发现,有效介电常数依赖于外加电场的频率,在高频条件下ω≥0.1-1 kHz,有效介电常数依赖于导电球与流体的介电常数比,而在低频或直流条件下,是电导率起主要作用.所得结果与相关实验结果基本吻合.