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。
Water vapor adsorption/desorption isotherms at 298 K and XRD measurements and nitrogen isotherms at 77 K before and after exposure to water vapor were determined on pure silica MCM-41 samples; samples had different pore widths and were prepared by different synthesis methods, including hydrothermal and room-temperatur…
Impregnation of hyper-cross-linked polystyrene (HPS) by either Co 2 (CO) 8 in 2-propanol or the [Co(DMF) 6 ] 2+ [Co(CO) 4 ] - 2 complex in dimethylformamide (DMF), followed by thermolysis at 200 °C, results in the formation of discrete Co nanoparticles. The concentration and characteristics of such nanoparticles were…
An effective photochemical route is reported here for size-controlled synthesis of nonaqueous colloidal gold particles in a highly polar and viscous medium, formamide in the presence of poly(vinylpyrrolidone). The effective photoreduction of AuCl 4 - in the nonaqueous system is attributed to the higher degree of disso…
The new biodegradable starch graft copolymer, starch- g -polycaprolactone (PCL), was synthesized by using the ring-opening graft polymerization of a ε-caprolactone (CL) monomer onto starch backbone. The grafting reactions were conducted with various starch/CL/water feed ratios to obtain starch- g -PCL copolymers with…
Steady-state luminescence spectroscopy and luminescence decay analysis have been employed to study the association of two rare earth ions (i.e., Eu 3+ and Tb 3+ ) with poly(ethylene glycol) in the absence and in the presence of 2,2‘-bipyridine, which acted as an antenna of near-UV radiation. Three different systems ha…
We previously demonstrated that metal nanoclusters ranging in size from 1 to 2 nm can be prepared within dendrimer templates. In this two-step synthesis, metal ions (for example, Cu 2+, Pd 2+, and Pt 2+ ) first partition into the interior of, for example, a hydroxyl-terminated poly(amidoamine) (PAMAM) dendrimer, and t…
Nanocomposite materials were prepared from an elastomeric medium-chain-length poly(hydroxyalkanoate) (Mcl-PHA) latex as semicrystalline matrix using a colloidal suspension of hydrolyzed cellulose whiskers as natural and biodegradable filler. After stirring, the preparations were cast and evaporated. High-performance m…
Mesoporous materials have been synthesized that are composed of hybrid frameworks in which inorganic and organic components have a fixed stoichiometry and are covalently bonded. The creation of UOFMN (unified organically functionalized mesoporous networks) materials incorporates concepts employed in the synthesis of M…
A theoretical study of Heisenberg exchange and double exchange interactions in iron–sulphur superclusters is presented. The clusters can play an important role in biological systems (proteins and enzymes) acting as so-called active centers. The cluster with valence 4+ can be modeled by four Fe(III) and two Fe(II) ions…
It is shown that fluids consisting of particles that interact with potentials containing an accessible hard core have elastic moduli at infinite frequency that are infinite in magnitude. A consequence of this is that such a fluid, at any density or temperature, is not viscoelastic as are all real fluids. The viscosity…
Raman spectroscopy of matrix-isolated, mass-selected Fe3 and Ag3 reveal that both are Jahn–Teller distorted triangular molecules. The observed spectrum of Ag3 can be accounted for adequately using an approximate Jahn–Teller potential truncated at the quadratic term [Wedum et al., J. Chem. Phys. 100, 6312 (1994)] with…
This paper describes the characterizations of structural and electrochemical properties of nanoparticle thin films derived by a one-step exchange−cross-linking−precipitation route. While there exists a stepwise layer-by-layer construction method, our motivation stems from seeking an alternative and simpler pathway to…
The superconducting proximity effect in single-walled carbon nanotubes connected to niobium electrodes was controlled with the use of nearby gates that tune the niobium-nanotube transparency. At 4.2 kelvin, when the transparency was tuned to be high, a dip in the low-bias differential resistance was observed, indicati…
p-type doping of molecular-beam-epitaxy grown layers of the diluted magnetic semiconductor Zn(1-x)MnxTe is achieved by using an active nitrogen cell. The strong interaction between the localized Mn spins and the holes deeply modifies the transport properties (metal-insulator transition, spin-dependent Hall effect). In…
The scaling behavior of cyclical surface growth (e.g. deposition/desorption), with the number of cycles n, is investigated. The roughness of surfaces grown by two linear primary processes follows a scaling behavior with asymptotic exponents inherited from the dominant process while the effective amplitudes are determi…
A large first-order magnetic phase transition in an organic radical, 1,3,5-trithia-2,4,6-triazapentalenyl, is described. The transition occurs with a wide thermal hysteresis loop over the temperature range 230 to 305 kelvin. The high-temperature phase is paramagnetic, and its structure consists of a uniform one-dimens…
Ferroelectric and paraelectric films deposited on dielectric and semiconductor substrates were studied at the frequency range 0.3-100 GHz and temperature interval 300-700 K in comparison with chemically equivalent bulk materials. A dielectric spectroscopy method helps to trace the change of dielectric polarization and…
Dynamical properties of bulk poly(propylene sulfide) (PPS) were investigated for a range of molar masses between 600 and 50 000 g/mol. The primary and secondary relaxation (α-relaxation and β-relaxation) were studied using dielectric spectroscopy. The local segmental relaxation (α-relaxation) and the chain backbone co…
Structures of water-insoluble complexes of polyethyleneimine (PEI) and fluorinated acids, varying in chain length from 4 to 16, were examined via contact angle measurements, X-ray diffraction, and infrared spectroscopy. The wettability of complex surfaces was shown to decrease with increasing chain length. The surface…
New heterobinucleating ligands for heme−Cu O2-reactivity studies feature a variably appended tridentate chelate {N,N-bis[2-(2-pyridyl)ethyl]amine} possessing an already established copper(I)/O2 chemistry. Reduced metal complexes have been synthesized and characterized. (3L)FeII (1a), a heme−Fe(II) empty-tether complex…