斜对角2×2分块算子矩阵的二次数值半径不等式

本文研究了Hilbert空间上斜对角2×2分块有界算子矩阵■的二次数值半径不等式,应用非负实数的经典凸性不等式推广了A的二次数值半径不等式.     

因子上非线性混合三重积保持映射

设$\mathcal{A}$, $\mathcal{B}$是两个因子且$\dim\mathcal{A}>4$.本文证明了双射$\phi:\mathcal{A}\rightarrow\mathcal{B}$ 满足对所有的$A,B,C\in\mathcal A$有$\phi([A,B]\bullet C)=[\phi(A),\phi(B)]\bullet\phi(C)$当且仅当$\phi$是线性*-同构, 共轭线性*- 同构,负的线性*-同构, 负的共轭线性*-同构.     

A general class of inequalities with mixed means

Suppose (T, Σ, μ) is a space with positive measure,f: ? → ? is a strictly monotone continuous function, and &;(T) is the set of real μ-measurable functions onT. Letx(·) ∈ &;(T) andf ○x)(·) ∈L ₁(T,μ). Comparison theorems are proved for the means $\mathfrak{M}_{(T,{\mathbf{ }}\mu ,{\mathbf{ }}f)} (x( \cdot ))$ and the mixed means $\mathfrak{M}_{(T_1 ,{\mathbf{ }}\mu _1 ,{\mathbf{ }}f_1 )} (\mathfrak{M}_{(T_2 ,{\mathbf{ }}\mu _2 ,{\mathbf{ }}f_2 )} (x( \cdot )))$ these inequalities imply analogs and generalizations of some classical inequalities, namely those of Hölder, Minkowski, Bellman, Pearson, Godunova and Levin, Steffensen, Marshall and Olkin, and others. These results are a continuation of the author's studies.     

Bodies with similar projections

Aleksandrov's projection theorem characterizes centrally symmetric convex bodies by the measures of their orthogonal projections on lower dimensional subspaces. A general result proved here concerning the mixed volumes of projections of a collection of convex bodies has the following corollary. If is a convex body in whose projections on -dimensional subspaces have the same -dimensional volume as the projections of a centrally symmetric convex body , then the Quermassintegrals satisfy , for , with equality, for any , if and only if is a translate of . The case where is centrally symmetric gives Aleksandrov's projection theorem.

     

Theoretical studies of (d-p)ρ bonding,electronic spectra,and reactivities in homo- and heterometallic clusters: [Mo3- n W n X4(H2O)9]4+ ( X = O,S, Se,Te;n= 0-3)

Ab initio calculations with relativistic effective potentials have been carried out on 12 trinuclear molybdenum/tungsten cluster aqua ions [M₃X₄(H₂O)₉]^4– (M₃= Mo₃, W₃ for X = O, S, Se, Te; M₃=Mo₂W, MoW₂ for X = O, S). The electronic structures and bonding pictures of l-12 are discussed in terms of the delocalized and localized molecular orbitals as well as the Mulliken populations, natural populations, and Mayer bond orders. It is shown that the (d-p) bonding in the puckered six-membered ring of the [M₃(µ-X)₃] core arises from a closed continuous ring of three mutually adjacent localized (d-p-d) bonds with strong interactions. It is these three-centered two-electron (d-p-d) bonds that account for the unusual physicochemical properties and reactivities of these cluster compounds. The wavelengths and the assignment of electronic spectra have been given, and the relation between the wavelength shili and the (d-p) bonding is discussed, The reactivities of the ligand substitution reactions and two kinds of addition reactions as weil as some kinetic and redox properties of these compounds are briefly discussed by taking advantage of this Iocalization (d-p-d) a bonding picture.     

LaSrCo0.9B’0.1O4复合氧化物制备、氧化性能及表征

采用聚丙烯酰胺法制备了类钙钛矿LaSrCo_0.9B’_0.1O₄系列复合氧化物(B’= Mn、Fe、Ni、Cu)和LaSrCoO₄,并考察了对CO和C₃H₈催化氧化反应的活性,运用XRD、BET、TEM、TPD等方法对LaSrCo_0.9Ni_0.1O₄、LaSrCoO₄进行了表征.结果表明, LaSrCo_0.9Ni_0.1O₄和LaSrCoO₄都为四方K₂NiF₄型纳米材料. Ni的掺入提高了LaSrCoO₄的催化活性、O₂的吸附量和晶格畸变率,降低了平均晶粒度.     

Solute activity coefficients in dilute aqueous electrolyte mixtures. III. The ternary system HClO4+UO2(ClO4)2+H2O at 25°C

Isopiestic vapor pressure comparison measurements were conducted with the three-component system HClO₄+UO₂(ClO₄)₂+H₂O in the concentration range between I=0.05 and 1.9m. Analysis of the mixture composition and concentration dependence of the osmotic coefficients with the Scatchard neutral-electrolyte and ion-component methods and with the Pitzer ioncomponent methods gave equally satisfactory results. Prediction of the observed osmotic coefficients by two-component approximations was satisfactory, and the data agreed well with values estimated with a model based on the osmolal fraction. A fair concordance was also found between predicted solute activity coefficients from simple models and values derived from complete treatments which included interaction terms.     

Chemischer Transport fester Lösungen. 17 [1] Der Chemische Transport von ZnS und CdS mit Phosphor — die Mischphase ZnS:P

Chemical Vapor Transport of ZnS and CdS with Phosphorus — ZnS:P mixed Crystals The volality of ZnS and CdS is enlarged in the presence of Phosphorus vapor. This is due to the formation of PS(g). By means of chemical vapor transport (1000 → 900 °C) using phosphorous as transport agent ZnS:P mixed crystals (sphalerit type) have been prepared. Density measurements on these mixed crystals show that interstitial zinc atoms are the consequence of the substitution of sulfur by phophorus atoms.     

Mo2(O2CPh)6(PEt3)2, the second example of bridging Y11-02CR for dimolybdenum (III) compounds

From the reaction or Mo₂Cl₆(THF)₃ with excess of NaO₂CPh and PEt₃ in THF three types of crystals have been obtained and recrystallized in CH₂Cl₂. They are brown compound Mo₂(O₂CPh)₆(PEt₃)2·2CH₂Cl₂ (1), yellow-Mo₂(O₂CPb)₄ (2), and black Mo₄O₆(O₂CPh)₆(PEt₃)₂.CH₂Cl₂ (3). When a strict ratio of MO₂Cl₆(THF)₃:NaO₂CPh = 1:2 was applied, Mo₂(O₂CPh)₄(THF)₂, (4) was the only compound separated from the THF reaction mixture. Their structures have been determined by X-ray crystallography. There are three coordination modes of benzoate in 1: bridging ²-O₂CPh, bridging ¹-O₂CPh and terminal O₂CPh groups. Compound 2 is chemically well known, but was found to pack differently from the previously reported structure. Mo₄O₆(O₂CPh)₆(PEt₃)₂·CH₂C1₂ (3) is a mixed-valence Mo (IV, V) tetranuclear compound in a butterfly arrangement. A molecule of 4 is actually a MO₂(O₂CPh)₄ molecule with two THIF molecules axially coordinating to the molybdenum atoms. The crystallographic data for these compounds are as follows: 1, triclinicPl witha = 11.612(3) Å, b = 11.970(2) Å,c=12.135(3) Å,=95.55(2)°,=117.51(2)°,98.84(2)°,V=l450.8(7) ų,Z=1,R=0.0673, and R _w ,=0.0936; 2, monoclinicP2₁/n witha = 14,437(2) Å,b=5.6168(7) Å,c=15.979(3) Å,=93,93(l)°,V=1292.7(4) ų,Z=2,R=0.0217, and R_w=0.0352; 3, trigonal (hexagonal setting)R3¯ witha=28.83(4) Å,c=44.98(2) Å,V=323570(10) ų,Z=18,R=0.067, andwR2=0203; 4 monoclinicP2₁/c witha=9.456(4) Å,b=17.757(8) Å,c=10.887(3) Å,=109.63(2)°,V=1722(2)ų Z=2,R=0.0330, andR _w = 0.0451.     

几种尖晶石型氧化物纳米粉体的制备及气敏性

采用化学共沉淀法合成了４种尖晶石型复合氧化物ＭＦｅ２Ｏ４（Ｍ＝Ｃｕ＾２＋，Ｚｎ＾２＋，Ｃｄ＾２＋，Ｍｇ＾２＋），Ｘ射线粉末衍射分析，透射电镜及比表面测定等表征结果表明它们均具较大比表面积的纳米粉体，平均粒径〈５０ｎｍ，将样品做成厚膜型气敏元件，测定了其对乙炔，液化石油气，一氧化碳、氢气和乙醇等还原（可燃）性气体的气敏特性。