Band structure and atomic sum rules for x-ray dichroism
Corrections to the atomic orbital sum rule for circular magnetic x-ray dichroism in solids are derived using orthonormal LMTOs as a single-particle basis for electron band states.
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Library Design in Combinatorial Chemistry by Monte Carlo Methods
Strategies for searching the space of variables in combinatorial chemistry experiments are presented, and a random energy model of combinatorial chemistry experiments is introduced. The search strategies, derived by analogy with the computer modeling technique of Monte Carlo, effectively search the variable space even…
Electromigration of Single-Layer Clusters
Single-layer atom or vacancy clusters in the presence of electromigration are studied theoretically assuming an isotropic medium. A variety of distinctive behaviors distinguish the response in the three standard limiting cases of periphery diffusion (PD), terrace diffusion (TD), and evaporation-condensation (EC). A ge…
Colloidal gelation and non-ergodicity transitions
Within the framework of the mode coupling theory (MCT) of structural relaxation, mechanisms and properties of non-ergodicity transitions in rather dilute suspensions of colloidal particles characterized by strong short-ranged attractions are studied. Results building on the virial expansion for particles with hard cor…
X-ray magnetic circular dichroism spectra on the superparamagnetic transition metal-ion clusters [Mn12O12(CH3COO)16(H2O)24].2CH3COOH.4H2O (Mn12) and [Fe8O2(OH)12(tacn)6]Br8 9H2O (Fe8)
The first X-ray magnetic circular dichroism (XMCD) spectra on the title compounds are presented. In Mn12 the Mn(III) and Mn(IV) contributions are clearly apparent and evidence the opposite spin arrangement of the two ions. For Fe8 the typical two peak structure of Fe(III) compounds is found. Quantitative analysis yiel…
Search for incoherent tunnel fluctuations of the magnetisation in nanoparticles of artificial ferritin
The magnetic behaviour of nanoparticles of antiferromagnetic ferritin, with a mean Fe loading of 410 atoms per core, has been investigated by 57Fe Mossbauer absorption spectroscopy down to very low temperature (34mK). In previous experi- ments of frequency dependent magnetic susceptibility and magnetic noise performed…
On non-linear susceptibility in supercooled liquids
In this paper, we discuss theoretically the behaviour of the four-point non-linear susceptibility and its associated correlation length for supercooled liquids close to the mode-coupling instability temperature T c . We work in the theoretical framework of the glass transition as described by mean-field theory of diso…
Polymer-Supported (Salen)Mn Catalysts for Asymmetric Epoxidation: A Comparison between Soluble and Insoluble Matrices
This paper describes the synthesis of both soluble and insoluble polymer-supported chiral (salen)Mn complexes and their use in asymmetric epoxidation reactions. These studies were undertaken to establish whether high enantioselectivities could be achieved with a polymer-bound catalyst and if the complexes could be rec…
Near-Infrared Luminescence from Small Gold Nanocrystals
A novel photoluminescence is reported for small metal nanocrystals in the near-infrared region (1.1−1.6 μm). Near-infrared photoluminescence spectra were measured at room temperature for 1.1 and 1.7 nm Au nanocrystals using a 1.06 μm excitation source. This photoluminescence is attributed to sp to sp-like transitions,…
Preparation of Noble Metal Nanowires Using Hexagonal Mesoporous Silica SBA-15
We demonstrate a novel preparation method for the formation of metallic nanowires from gold, platinum, and silver using mesoporous silica SBA-15 as a template. SBA-15 controls the size and the growth direction of the nanowires and also prevents bulk aggregation of the metal. Nanowires can be isolated from the silica f…
Resistivity-volume expansion characteristics of carbon black-loaded polyethylene
The resistivity and volume expansion of carbon black (CB)/high-density polyethylene (HDPE) composite with different CB volume fractions at different temperatures were measured simultaneously. A model based on Meyer's theory is proposed to explain the positive temperature coefficient resistance (PTCR) effect. The relat…
Further study on double-melting endotherms of isotactic polypropylene
The origins of the single- and double-melting endotherms of isotactic polypropylene crystallized at different temperatures were studied carefully by differential scanning calorimetry, wide-angle X-ray diffraction, and small-angle X-ray scattering. The experimental data show that spontaneous crystallization occurs when…
Compatibilizing effect of diglycidyl ether of bisphenol-A in polymer blend system: Nylon 6 combined with poly(butyl acrylate) core and poly(methyl methacrylate) shell particles
A polymeric blend system of nylon 6 and a core–shell impact modifier was studied. The modifier had a poly(butyl acrylate) core and a poly(methyl methacrylate) (PMMA) shell compatibilized with an epoxy resin, diglycidyl ether of bisphenol-A (DGEBA). The compatibilization of DGEBA is achieved by the reaction of its glyc…
Graft copolymerization of acrylic acid onto guar gum
The graft copolymerization of acrylic acid (AA) onto guar gum (GOH) was carried out by a peroxydiphosphate (PDP)–silver(I) system. Grafting ratio, efficiency, add-on, and conversion increase upon increasing the concentration of PDP and acrylic acid, whereas they decrease upon increasing the concentration of guar gum.…
Synthesis of sulfhydryl chitin and its adsorption properties for heavy metal ions
This article discusses the preparation of the water-insoluble adsorbent sulfhydryl chitin (s-chitin), by treatment of the chitin with sulfhydryl acetic acid in the presence of sulfuric acid as a catalyst. Its structure was confirmed by elemental analysis, FTIR spectra analysis and near-IR spectra analysis. We also inv…
Study on compatibility of PP-STC blends functionalized by ultraviolet irradiation
To enhance the compatibility of polypropylene (PP) with sericite–tridymite–cristobalite (STC), polypropylene was irradiated by low-energy ultraviolet (UV) irradiation within 2.5 h to introduce the oxygen-containing groups onto the PP chains. From blending the UV-irradiated polypropylene with STC, the effects of the co…
Influence of diethanolamine (DEOA) on structure-property behavior of molded flexible polyurethane foams
In this study, the viscoelastic and morphological properties of molded foams were investigated to determine the influence of varying the concentration of diethanolamine (DEOA), a commercially utilized crosslinking agent. FTIR and WAXS analyses showed that DEOA had a disrupting effect on the bidentate hydrogen bonding…
Preparation of electrically conducting polypyrrole in oil/water microemulsion
Nanoscopic conducting polypyrrole powder was prepared in an oil/water microemulsion with FeCl3 as a dopant. Compared with solution and conventional emulsion polymerizations, a microemulsion polymerization system increases the yield of the resultant polypyrrole. The results of FTIR spectra and thermal analysis studies…
Effect of P(lLA-co-?CL) on the compatibility and crystallization behavior of PCL/PLLA blends
This article describes the compatibility of two semicrystalline polymers, poly(ε-caprolactone) (PCL) and poly(l-lactic acid) (PLLA). The compatibility of the PCL/PLLA blends was enhanced by the compatibilizing effect of the poly(l,l-lactide-co-ε-caprolactone) [P(lLA-co-εCL)]. A discussion details the effect of the con…
The ground state of Sr3Ru2O7 revisited; Fermi liquid close to a ferromagnetic instability
We show that single-crystalline Sr3Ru2O7 grown by a floating-zone technique is an isotropic paramagnet and a quasi-two dimensional metal as spin-triplet superconducting Sr2RuO4 is. The ground state is Fermi liquid with very low residual resistivity (3 micro ohm cm for in-plane currents) and a nearly ferromagnetic meta…