The law of the solution to a nonlinear hyperbolicSPDE

Let { _s,t ,(s,t ₊ ² } be a white noise on ₊ ² . We consider the hyperbolic stochastic partial differential equation {ie863-3} The purpose of this paper is to study the law of the solution to this equation. We analyze the existence and smoothness of the density using the tools of Malliavin Calculus. Finally we prove a large deviation principle on the space of continuous functions, for the family of probabilities obtained by perturbation of the noise in the equation.This work has been partially supported by the grant of the DGICYT No. PB 930052 and the EU Science project CT 910459.     

Where are the Sn atoms in LaSb2Snx, 0.1?x?∼0.75?

The composition range and (composite modulated) structure of compounds within the wide range non-stoichiometric LaSb₂Sn_x, 0.1?x?0.75, solid solution is carefully investigated via a combined electron diffraction, XRD and electron probe microanalysis study. Evidence for metastability of the LaSb₂Sn_x phase at the low x composition end of the solid solution is presented. Direct evidence is found for a reasonably (although by no means perfectly) well ordered Sn sub-structure which is, in general, mutually incommensurable with respect to a very well ordered underlying LaSb₂ sub-structure along both a and c directions. The overall (3+2)-d superspace group symmetry is given along with a discussion of the consequences as regards the arrangement of the Sn atoms. The Sn sub-structure c-axis cell dimension shows very little variation with composition x providing direct experimental evidence of the importance of Sn-Sn metallic bonding (along one-dimensional [001] Sn strings) for the stability of the phase.     

用θ-2θ型衍射仪测定溶液结构的新方法

叙述了用θ－２θ型Ｘ射线衍射仪精确测定电解质溶液结构的新实验技术。设计制作了具有恒温功能的超厚液体样品池，并建立了样品池窗口强度的校正方法。优化了液体Ｘ射线衍射数据和结构参数精细化的计算机程序，获得了非常令人满意的实验结果。由θ－２θ型Ｘ射线衍射仪精确测定的径向分布函数与θ－θ型衍射仪自由散射比较，表明ＤＲＦ分辨率有所提高。     

Effect of pressure on the adsorption and micelle formation of aqueous dodecyltrimethylammonium chloride solution-hexane system

The interfacial tension of aqueous dodecyltrimethylammonium chloride (DTAC) solution/hexane interface has been measured as a function of pressure at concentrations around the critical micelle concentration (CMC). The derivative of the interfacial tension with respect to pressure has been observed to change abruptly at the CMC as in the case of aqueous dodecylammonium chloride (DAC) solution-hexane system studied already. The volume changes associated with the adsorption of DTAC from its monomeric and micellar states have been calculated. The results have indicated that the micelle formation of surfactant is treated like the appearance of a new macroscopic phase in the system. It has also been concluded that the micelle solubilizing hexane bears resemblance to the adsorbed film in terms of the volume. The difference in the pressure dependence of the volume of micelle formation ^MW between DTAC and DAC has been attributed to a larger polar group of DTAC. The fact that the value of ^MW is larger than that estimated from the conductivity data has been explained by the solubilization of hexane into the micelle.     

Solute-solvent interactions in water-tert-butyl alcohol mixtures. VI. Enthalpies of solution for halo-para-substituted benzoates

Enthalpies of solution of sodium benzoate, potassium benzoate, and potassium halo-substituted benzoates are reported at 298.15°K in water and in nine water-tert-butyl alchol mixtures. Transfer enthalpies from water to the mixed solvent go through a maximum for about 0.055 mole fraction of alcohol. Additivity of ionic contributions in the enthalpies of transfer is verified. Substituent effects on the transfer enthalpies of benzoates are discussed in terms of size of the solutes and cohesion of the solvent mixtures. For Part V, see ref. 1.     

Solubility and Flory Huggins parameters of SBES, poly(styrene-b-butene/ethylene-b-styrene) triblock copolymer, determined by intrinsic viscosity

Solubility parameter and Flory Huggins interaction parameter of a triblock SBES have been obtained from intrinsic viscosity measurements. The solubility of the block copolymer in all solvents (methyl-cyclohexane, cyclohexane, cyclopentane, toluene and benzene) was found good except in the case of n-hexane. The results obtained are similar to other found in literature for SBR and SBS rubbers, and indicate that cyclohexane and cyclopentane and methylcyclohexane are the most compatible solvents for this kind of polymer.     

Subsolidus phase relations and crystal structure of compounds in the PrOx-CaO-CuO system

The subsolidus phase relations of the PrO_x-CaO-CuO pseudo-ternary system sintered at 950-1000°C have been investigated by X-ray powder diffraction. In this system, there exist one compound Ca₁₀Pr₄Cu₂₄O₄₁, one Ca₂Pr₂Cu₅O₁₀-based solid solution, seven three-phase regions and two two-phase regions. The crystal structures of Ca₁₀Pr₄Cu₂₄O₄₁ and Ca₂Pr₂Cu₅O₁₀-based solid solution have been determined. Compound Ca₁₀Pr₄Cu₂₄O₄₁ crystallizes in an orthorhombic cell with space group D_2h²⁰−Cccm, Z=4. Its lattice parameters are a=11.278(2) Å, b=12.448(3) Å and c=27.486(8) Å. The crystal structure of Ca₂Pr₂Cu₅O₁₀-based solid solution is an incommensurate phase based on the orthorhombic NaCuO₂ type subcell. The lattice parameters of the subcell of the Ca_2.4Pr_1.6Cu₅O₁₀ are a₀=2.8246(7) Å, b₀=6.3693(5) Å, c₀=10.679(1) Å, and those of the orthorhombic superstructure are with a=5a₀, b=b₀, c=5c₀. The Ca_2.4Pr_1.6Cu₅O₁₀ structure can also be determined by using a monoclinic supercell with space group C_2h⁵−P2₁/c, Z=4, a=5a₀, b=b₀, and β=104.79(1)° or 136.60(1)°, V=5a₀b₀c₀.     

A critical reappraisal of recent communications on the hydrodynamic characterization of silica (aerosil) hydrosols

Different results from recent communications on the hydrodynamic characterization of ultrasonicated silica (®Aerosil) hydrosols led to a critical reappraisal of the data.It can be concluded that the degree of dispersion achievable in pyrogenic (Aerosil) hydrosols by ultrasonication is highly sensitive to the detailed parameters of the dispersion process. Characterization in terms ofabsolute numbers of a limiting particle morphology, corresponding to minima of aggregate size, porosity and number of primary particles in the aggregate is not possible.The most straightforward approach for hydrodynamic characterization seems to be a combination of sedimentation and diffusion data.Other approaches using a combination of sedimentation and viscosity data underestimate the particle dimensions. Moreover, they are quite arbitrary since the final result depends upon the proper choice between several equations for fitting the viscosity concentration dependence; the most rigorous approach seems to be an extended Einstein equation which has recently been adapted to particle aggregates.     

Synthesis and characterization of new polyamides derived from di(4-cyanophenyl)isosorbide

New optically active polyamides were synthesized according to two ways: using a microwave-assisted polycondensation of an optically active isosorbide-derived diacylchloride with different aromatic diamines in NMP and using interfacial polymerization from an isosorbide-derived diamine with different diacylchlorides. The polymers are obtained with inherent viscosities in the range from 0.11 to 1.05 dL/g. The DSC and TGA measurements clearly demonstrate the high thermal stability of these polymers when considering the range of the melting points from 200 °C to 300 °C and the absence of decomposition till 350 °C.     

化学镀钴基合金镀液中钴的快速测定

研究了采用显色剂 苦胺酸偶氮变色酸对化学镀钴基合金镀液中钴含量进行测定的试验条件,在pH11的氨 氯化铵缓冲溶液中,钴与显色剂配合物的最大吸收峰在650nm波长处,钴(Ⅱ)在0～60μg/25ml范围内服从比耳定律,表观摩尔吸光系数为3.1×104L·mol-1·cm-1。该法测定钴的选择性好,在大量镍存在下,也能准确测定,对镀液样品进行了测定,相对标准偏差小于1%,结果满意。