Thermal Expansion Behavior of La1—xSrxMn1—yCoyO3—δ Perovskites

The thermal expansion behavior of La1-xSrxMn1-yCoyO3-δ (x=0.2-0.4, y=0.1-0.3) perovskites in air has been investigated. The average linear thermal expansion coefficients increased with increasing Sr content up to 40 mole fraction or Co content up to 30 mole fraction. The expansion is generally attributed to an increase in the average cation radius as some of the cations in the perovskite are reduced in valence when oxygen ions are removed from the structure.     

Effect of Cu concentration on the reactions between Sn-Ag-Cu solders and Ni

The reaction between the Sn-Ag-Cu solders and Ni at 250°C for 10 min and 25 h was studied. Nine different Sn-Ag-Cu solders, with the Ag concentration fixed at 3.9 wt.% and Cu concentrations varied between 0.0–3.0 wt.%, were used. When the reaction time was 10 min, the reactions strongly depended on the Cu concentration. At low-Cu concentrations (≦0.2 wt.%), only a continuous (Ni_1−xCu_x)₃Sn₄ layer formed at the interface. When the Cu concentration increased to 0.4 wt.%, a continuous (Ni_1−xCu_x)₃Sn₄ layer and a small amount of discontinuous (Cu_1−yNi_y)₆Sn₅ particles formed at the interface. When the Cu concentration increased to 0.5 wt.%, the amount of (Cu_1−yNi_y)₆Sn₅ increased and (Cu_1−yNi₆)₆Sn₅ became a continuous layer. Beneath this (Cu_1−yNi_y)₆Sn₅ layer was a very thin but continuous layer of (Ni_1−xCu_x)₃Sn₄. At higher Cu concentrations (0.6–3.0 wt.%), (Ni_1−xCu_x)₃Sn₄ disappeared, and only (Cu_1−yNi_y)₆Sn₅ was present. The reactions at 25 h also depended strongly on the Cu concentration, proving that the strong concentration dependence was not a transient phenomenon limited to a short reaction time. The findings of this study were rationalized using the Cu-Ni-Sn isotherm. This study shows that precise control over the Cu concentration in solders is needed to produce consistent results.     

Al-Cu-Fe QUASICRYSTALLINE PHASE FORMATION BY MECHANICAL ALLOYING

Al-Cu-Fe alloys were prepared from elemental powders in a high-energy planetary ball mill. A sequence of solid state reactions resulting in quasicrystal (QC) phase formation takes place during heating of the as-milled powder. These reactions were studied by both differential scanning calorimetry and x-ray diffraction methods. Mechanically alloyed powders were consolidated by cold and hot pressing, as well as by explosive compaction. After annealing at sufficiently high temperatures, the consolidated samples are single-phase QC, except the ones consolidated by explosion. The high reactivity of the as-milled alloys causes the appearance of high porosity of the consolidated samples after the annealing.     

纤维素的辐射裂解及其化学性质

纤维素经高能射线辐照,能产生一系列的化学和物理性质的变化。本文报道在不同剂量的~(60)Coγ射线辐照下,稻草中的水溶性糖、易水解糖、难水解糖,以及氨基酸、蛋白质等物质的化学变化;用辐射与加泡涨剂相结合的方法处理稻草,可以降低剂量、提高效应。     

Thermodynamic Aspects of Aromatic Hydrogenation

Aromatic hydrogenation is one of the important classes of hydrotreating reactions and its thermodynamics play a significant role in achieving the product specifications. This article comprehensively reviews the available experimental thermodynamic data as well as the methods to estimate the data for aromatic hydrogenation. The data indicate that aromatic hydrogenation reactions are thermodynamically more favorable at about 200°C-250°C and moderate pressures (3-5 MPa). Industrially, however, these reactions are carried out at 300°C-375°C to have reasonable kinetics. Hence there is a need for highly active catalysts, which can facilitate significant kinetics of hydrotreating reactions at around 200°C-250°C.     

Pu(OH)4(am)与碳酸根的配位行为研究

为了解在惰气环境Pu(OH)_4(am)与碳酸盐溶液中HCO^-₃，CO^2-₃的配位行为，考察了放置时间对Pu总浓度的影响；同时也考察了pH值、碳酸根总浓度变化对碳酸盐溶液中Pu的主要存在形态及溶解总浓度的影响。实验结果表明，HCO^-₃离子与Pu(OH)_4(am)生成[Pu(OH)₄(HCO₃)₂]^2-（lg K=-2.61±0.18, lgβ=54.25±0.18）或[Pu(OH)₂(CO₃)₂]^2-（lgK=-2.61±0.18, lgβ=46.91±0.18）；CO^2-₃离子与Pu(OH)_4(am）生成[Pu(OH)₄(CO₃)₂]^4-（lgK=-3.52±0.11, lgβ=53.33±0.11）。可能的配位反应方程式为： Pu(OH)_4(am)+2HCO^-₃ = [Pu(OH)₄(HCO₃)₂]^2-, Pu(OH)_4(am)+2HCO^-₃ =[Pu(OH)₂(CO₃)₂]^2-+2H₂O, Pu(OH)_4(am)+2CO^2-₃=[Pu(OH)₄(CO₃)₂]^4-。     

Profile-Based Linguistic Uniformity as a Generic Method for Comparing Language Varieties

In this text we present``profile-based linguistic uniformity', a methoddesigned to compare language varieties on thebasis of a wide range of potentiallyheterogeneous linguistic variables. In manyrespects a parallel can be drawn with currentmethods in dialectometry (for an overview, see,Nerbonne and Heeringa, 2001; Heeringa, Nerbonneand Kleiweg, 2002): in both casesdissimilarities between varieties on the basisof individual variables are summarized inglobal dissimilarities, and a series oflanguage varieties are subsequently clusteredor charted using multivariate techniques suchas cluster analysis or multidimensionalscaling. This global similarity between themethods makes it possible to compare them andto investigate the implications of notabledifferences. In this text we specifically focuson, and defend one characteristic of ourmethodology, its profile-based nature.     

溶液中微量甲基异丁基酮的分析方法

研究了微量甲异丁基酮在氟氧铌酸（H2NbOF5)及氟钽酸（H2TaF7)溶液中存在的形式，找到利用碘仿-硫代硫酸钠联合滴定的方法，来标定微量甲基异丁基酮在H2NbOF5及H2TaF7溶液中的含量，本方法在钽铌冶炼过程中操作简便易行且结果重现性好。     

Review of Arthur R. Jensen (2006)--Clocking the mind: Mental chronometry and individual differences.

Reviews the book Clocking the Mind: Mental chronometry and individual differences by Arthur Jensen (see record 2006-20276-000). Mental chronometry, as Arthur Jensen stresses, is the study of reaction time (RT) in its various guises, contexts, and applications. As with respect to much of experimental psychology (cognitive and other), there is a venerable past here lying in the background, providing a wide-ranging context in which to embed our current (that is, our 40-odd year) preoccupation with RT as a primary dependent measure in cognitive psychology. This recent book, Clocking the Mind: Mental Chronometry and Individual Differences (published by Elsevier), weds both differential psychology's concern with the measurement of individual differences in RT (e.g., Austin, Deary, Gibson, McGregor, & Dent, 1998) and experimental psychology's concern with "the effects of manipulating various external conditions on variation in the measurements of RT" (p. 1). The reader of this journal will most probably be more familiar with the latter use of RT in the literature, especially when embedded within such familiar experimental tasks as those tapping both Garner and Stroop effects (Pansky & Algom, 1999). The book should be perused with care in order to ensure the further profitable use of RT in both experimental and differential lines of research. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Kinetic Studies of the Thermal Decomposition of C60H2 in Solution

Thermal decomposition of C₆₀H₂ in C₆D₄Cl₂ solution at 236°C for 2 hours was shown to produce hydrogen as a product, the hydrogen production was successfully followed by NMR. In order to further explore the rule of thermal decomposition of C₆₀H₂, the dynamics of decomposition reaction was studied and the results showed this decomposition reaction accorded with first order reaction dynamical equation. The experiment temperature was ranged separately in 459K, 455K, 451K, and 446K.