Materials Literature
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Chemical control over the size of nanoparticles is a prerequisite for their application. The synthesis of protective polymers having cyano or mercapto groups (e.g., MMS-NVP, see Figure) is reported, together with the influence of these polymers on the size and size distribution of gold nanoparticles synthesized by KBH…
Electrooptical and structural studies on self-assembled films composed of CdSe nanoparticles, poly( p -phenylene vinylene) (PPV), and different nonconjugated polyelectrolytes are reported. It is demonstrated by optical spectroscopy and X-ray reflectivity measurements that CdSe nanoparticles and PPV can successfully be…
Molecular dynamics (MD) simulations are used to study the static and dynamic properties of 2:1 layered silicates ion exchanged with alkyl-ammonium surfactants. These systems are in the form of oligomeric alkanes grafted by cationic groups on atomically smooth crystalline layers 10 Å thick and several microns wide. The…
A survey is given on recent research on “metal dusting” i.e. a catastrophic carburization or rather graphitization of metals and alloys occuring in carbonaceous atmospheres at carbon activities aC>1. The thermodynamics are explained, the mechanisms for iron, low and high alloy steels, nickel and Ni-base alloys are des…
We consider the approach to saturation for cubic and uniaxial polycrystalline, single-domain ferromagnets from the remanent state. For both cubic {111}- and {100}-easy systems we find that the coefficient \ensuremath{\beta} in the law $M(H)\underset{\stackrel{\ensuremath{\rightarrow}}{H}\ensuremath{\infty}}{\ensuremat…
Abstract The study of weathering and erosion processes requires the establishment of a mass balance of minerals from the soils towards the sedimentation area. This calls for the development of quantitative tools that can be applied to mixtures of finely divided and sometimes poorly crystallized minerals found in soils…
By studying the dynamics of the metastable magnetization of a statistical mechanical model we propose a switching mechanism of photoinduced magnetization. The equilibrium and nonequilibrium properties of the Blume-Capel (BC) model, which is a typical model exhibiting metastability, are studied by mean field theory and…
Using a Green's function approach, we investigate band structure effects in the BEEM current distribution in reciprocal space. In the elastic limit, this formalism provides a 'parameter free' solution to the BEEM problem. At low temperatures, and for thin metallic layers, the elastic approximation is enough to explain…
We present a Green's function approach based on a LCAO scheme to compute the elastic propagation of electrons injected from a STM tip into a metallic film. The obtained 2D current distribution in real and reciprocal space furnish a good representation of the elastic component of Ballistic Electron Emission Microscopy…
The relationship between amino acid sequence, three-dimensional structure and biological function of proteins is one of the most intensely pursued areas of molecular biology and biochemistry. In this context, the three-dimensional structure has a pivotal role, its knowledge being essential to understand the physical,…
The creep viscosity of chemical‐precursor‐derived silicon carbonitride (SiCN), which is known to remain predominantly amorphous at temperatures below 1400°C, was measured in the temperature range 1090‐1280°C. Experiments were done in uniaxial compression at constant loads in pure nitrogen atmosphere. The creep behavio…
Equilibrium phase relationships in the ZnO‐In 2 O 3 system were determined between 1100° and 1400°C using solid‐state reaction techniques and X‐ray diffractometry. In addition to ZnO and In 2 O 3 , nine homologous compounds, Zn k In 2 O k +3 (where k = 3, 4, 5, 6, 7, 9, 11, 13, and 15), were observed. Electrical condu…
Abstract Bis(3-triethoxysilylpropyl)tetrasulfide (TESPT) was found to affect the curing characteristics and the physical properties of styrene-butadiene (SBR) gum rubber and xin situ silica-filled SBR vulcanizates. Silica incorporated by the in situ sol-gel reaction of tetraethoxysilane with TESPT showed a much higher…
In freshwater environments such as river and stream bottoms, rocks and submerged vegetation are covered with a biological felt (also called a periphyton, microbial mat, biofilm, etc.) that is susceptible to calcification. Compilation of an extensive bibliography and our own observations have allowed the identification…
Random aliphatic-aromatic copolyesters synthesized from 1,4-butanediol, adipic acid, and terephthalic acid (BTA) have excellent thermal and mechanical properties and are biodegradable by mixed cultures (e.g., in compost). Over 20 BTA-degrading strains were isolated by using compost as a microbial source. Among these m…
Values of the transmittance T(s) and the phaseretardation D were recorded in situ at two angles duringthe growth of thin films of tantalum oxide, titanium oxide, andzirconium oxide for deposition angles theta(nu) in the range40 degrees -70 degrees . Column angles for the same films were determinedex situ from scanning…
This review is devoted to the description of recent experimental results concerning the nonlinear optical properties of semiconductor-doped glasses SDGs with particular emphasis on the regime in which the energy of the incident photon is smaller than the energy gap. A considerable theoretical and experimental effort h…
The anionic ruthenium cluster carbonylates [Ru6C(CO)16]2- or [H2Ru10(CO)25]2- interspersed with bis(triphenylphosphino)iminium counterions (PPN+) are incorporated from solution into the pores of MCM-41 mesoporous silica (3 nanometers in diameter), where they form tightly packed arrays. These arrays were shown by high-…
We present results based on local-spin-density calculations of a computational search for half-metallic (HM) antiferromagnetic (AFM) materials within the class of double-perovskite-structure oxides $\mathrm{La}{M}^{\ensuremath{'}}{M}^{\ensuremath{''}}{\mathrm{O}}_{3}$ that incorporate open-shell $3d$ (or $4d)$ transit…
Purification of single-shell nanotubes is essential if reliable information about their physical and chemical properties is to be obtained. Using the present synthetic techniques, samples typically contain 30% or more amorphous carbon and catalytic metal particle impurities. An extremely simple and efficient method of…