Materials Literature
按标题、摘要、年份、主题和来源检索公开元数据。结果保留作者、摘要、分类与原始来源链接。
The growth and dynamics of solid surfaces displays a multitude of power law relationships, which are often associated with geometric self-similarity. In many cases the mechanisms behind these power laws are comparatively trivial, and require little more than dimensional analysis for their derivation. The information o…
By employing a real-space formulation of the Kubo-Greenwood equation based on a Green's function embedding technique combined with the fully relativistic spin-polarized Korringa-Kohn-Rostoker method a detailed investigation of the electrical transport through atomic-scaled contacts between two Au(001) semi-infinite sy…
We present a detailed analytical and numerical analysis of the nuclear spin dynamics in parabolic quantum wells. The shallow potential of parabolic quantum wells permits substantial modification of the electronic wave function in small electric fields. The nuclear spin relaxation via the hyperfine interaction depends…
Tridentate/tetradentate Schiff base ligands L(1) and L(2), derived from the condensation of o-vanillin or pyridine-2-aldehyde with N,N-dimethylethylenediammine, react with nickel acetate or perchlorate salt and azide, cyanate, or thiocyanate to give rise to a series of dinuclear complexes of formulas [Ni(L(1))(micro(1…
This paper presents results of first-principles calculations of nuclear magnetic resonance (NMR) parameters: the chemical shielding tensor and the electric field gradient tensor, of some crystalline and amorphous sodium silicate systems. The calculations have been performed using the recently introduced gauge includin…
Rich populations of clusters have been observed after femtosecond laser ablation of bulk silicon in vacuum. Size and velocity distributions of the clusters as well as their charge states have been analyzed by reflectron time-of-flight mass spectrometry. An efficient emission of both neutral silicon clusters Sin (up to…
The simulation study on Frenkel pair creation in vanadium by L.A. Zepeda-Ruiz et al. (Phys. Rev. B 67, 134114, 2003) is criticized for its lack of reference to existing experimental work and for generally inadequate treatment of literature data. Hence, the validity of the ensuing discussion of various results (e.g. th…
From a multiple scale analysis, we find an analytic solution of spherical and cylindrical Poisson-Boltzmann theory for both a 1:2 (monovalent co-ions, divalent counter-ions) and a 2:1 (reversed situation) electrolyte. Our approach consists in an expansion in powers of rescaled curvature $1/(κa)$, where $a$ is the coll…
We report here the first synthesis of pure boron single-wall nanotubes by reaction of BCl 3 with H 2 over an Mg−MCM-41 catalyst with parallel, uniform diameter (36 ± 1 Å) cylindrical pores. The composition of the tubular structures observed in TEM was confirmed by electron energy loss spectroscopy, and the tubular geo…
Isotopic tracer and kinetic studies are used to probe the identity and reversibility of elementary steps required for H 2 O and CO 2 reforming of CH 4 on supported Pt clusters and to demonstrate a rigorous kinetic and mechanistic equivalence for CO 2 and H 2 O reforming, CH 4 decomposition, and water-gas shift reactio…
The flowerlike ZnO nanostructures, which consisted of swordlike ZnO nanorods, have been prepared by a cetyltrimethylammonium bromide (CTAB)-assisted hydrothermal process at low temperature (120 °C). The XRD pattern indicated that the flowerlike ZnO nanostructures were hexagonal. Furthermore, the SAED and HRTEM reveale…
A new circular position sensor based on giant magnetoresistances has been developed. The sensing film is an AgCo nanogranular thin film patterned in a circular Wheatstone bridge configuration. This alloy shows a high magnetoresistance (8%) at room temperature within the field generated by an NdFeB permanent magnet tha…
Multilayers of alternately adsorbing poly(allylamine) (PAH) and poly(acrylic acid) (PAA) of opposite charges on silica have been studied by the spin labeling technique, as a function of pH. The two polyelectrolytes have been labeled independently by a nitroxide free radical. Its electron paramagnetic resonance spectru…
A new carbon-13 NMR method is presented for the quantitative determination of monomer sequence distributions and average sequence lengths in propylene−1-butene copolymers. Complete carbon-13 NMR chemical shift assignment was finalized: the peaks corresponding to comonomeric sequence distributions are assigned in terms…
The local and intermediate structure of a simulated metal−metalloid glass-forming alloy is reported. The model, due to Kob and Andersen, has been the subject of considerable study in the context of the glass transition. In the A 75 B 25 mixture the low-temperature coordination polyhedra about the B (“metalloid”) parti…
We investigate, using small-angle neutron scattering (SANS), the polymer concentration fluctuations in a particular type of end-linked polystyrene gels, in the swollen state. These gels are obtained from the cross-linking of well-defined end-capped low-polydispersity chains end-linked through a trifunctional cross-lin…
Silica monoliths with ordered arrays of micrometer-scale columns were fabricated from polyacrylamide gel templates. The preparation of the template involves the charged comonomer, N-acryloyl glycine, and is controlled by an externally applied electric field. This approach gives rise to the self-organization of columna…
Abstract The thermal degradation and flame retardancy of poly(butylene terephthalate) (PBT) were studied with a focus on the effect of phosphorous compounds. Thermogravimetric analysis, pyrolysis/gas chromatography/mass spectrometry (Py/GC/MS), and elemental analysis were used to analyze the flame retardancy, which we…
Aerogels with the nominal composition ZrW 2 O 8 have been prepared by pore solvent exchange with liquid CO 2 followed by supercritical drying. These aerogels are amorphous and can be tailored to have extremely high surface areas. Thermal expansion is measured for the amorphous aerogel as well as the aerogel post therm…
Rohr oder Röhrchen? Entgegen früheren theoretischen Untersuchungen ergaben Dichtefunktionalrechnungen (B3LYP/6-31G*) an unterschiedlichen Nanoröhrenmodellen, dass SWCNTs mit O-, NH-, CH2- und SiH2-Addenden offene Strukturen gegenüber Dreiringen bevorzugen. Ferner sind in (8,0)-Zickzack-Nanoröhren die diagonalen C-C-Bi…