Materials Literature
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We describe and characterize a simple process for the fabrication of patterned materials on polychloromethylstyrene thin film surfaces under ambient conditions. Patterned deep UV exposure (approximately 60 mJcm(-2), 193 nm) efficiently oxidizes the surface C-Cl bonds of the polymer film, producing an aldehyde species…
The adsorption and chemical transformation of iodoethane were studied on a Si(100)-2×1 surface using multiple-internal reflection Fourier-transform infrared spectroscopy (MIR-FTIR). The C–H and Si–H stretch vibrations served as fingerprints of all surface transformations. Although ethyl groups are stable on the Si(100…
Polyelectrolytes functionalized with photoisomerizable azobenzene chromophores were multi-layered onto inorganic and metal surfaces, by the repeated adsorption from dilute aqueous solution, alternating between oppositely charged polymers. These layer-by-layer ionically self-assembled thin films were investigated for t…
We have studied the growth and the properties of (t)a-C:F films prepared by the deposition of mass separated 12C+ and 19F+ ions as a function of the F concentration. The films are always strongly F deficient due to the formation of volatile F2 and CFx molecules during the deposition process. A maximum F content of abo…
Porosity and acidity of molecular sieve Al-MCM-41 (ca. 30 A pore diameter) plays a crucial role in the synthesis of novel calix(4)pyrroles; for the first time, Al-MCM-41 has been used as a solid acid catalyst to produce a number of calix(4)pyrroles with good selectivity ad yields where zeolite HY (ca. 7.6 A pore diame…
Electrochemical evidence of H. produced by cavitation as the result of ultrasonic irradiation of an aqueous solution is presented.
An insulated nanotube wire is formed by the binary phase of layered tungsten disulphide and carbon nanotubes (shown in the HRTEM image) generated by the sulphidization of tungsten oxide coated multiwalled carbon nanotubes at 900 °C. Thermogravimetric analysis shows that the tungsten disulphide coat acts as an antioxid…
To gain insight into the molecular aspects of unfolding/refolding of enzymes from extremophilic organisms, we have used xylanase from an alkalophilic thermophilic Bacillus as the model system. Kinetics of denaturation/renaturation were monitored using intrinsic fluorescence studies. The protein fluorescence measuremen…
Structural and electronic properties of semiconductor binary microclusters ${A}_{m}{B}_{n}$ $(A,B=\mathrm{S}\mathrm{i},\mathrm{G}\mathrm{e},\mathrm{C})$ have been investigated using the B3LYP-DFT method in the range $s=m+n<~10.$ Full structural optimization and frequency analyses are performed with the basis of $6\…
A laterally segregated diffusion barrier was investigated for Cu metallization. In this scheme, the intended final structure is composed of two different barrier materials; one is the parent barrier layer (TiN, in our case) and the other (Al2O3, in this case) is segregated laterally along the grain boundaries of the p…
A polyimide that is designed to produce homeotropic liquid-crystal orientation is baked at high temperature and rubbed with a cotton cloth. It is found that the resulting pretilt angle of the liquid-crystal pentylcyanobiphenyl is continuously controllable from 0° to nearly 40°.
We present the model of a cylindrical pore with chains tethered by one end to its inner surface. The conformational and “quasistatic” (under low and medium shear rates) hydrodynamic properties of the system are studied. Since it was shown by other researchers that the density profile of the polymer layer is only sligh…
Co 0.2 Zn 0.8 Fe 2 O 4 nanoparticles have been synthesized by the coprecipitation method. Nanoparticles with average particle size of 5–∼65 nm were obtained by sintering the samples from 393 to 1173 K. Magnetic measurements show that samples with particle size ⩽13 nm are superparamagnetic above the blocking temperatur…
Porous silicon (PS) based metal/PS/p-Si structures with PS layer of different thickness were prepared on moderate- and high-resistivity substrates. Measurements of current–voltage (I–V) characteristics and impedance at various temperatures were used for the investigation of the electrical properties of these structure…
Defined porosity in the low-nanometer range is exhibited by easy-to-modify template materials, which can be prepared from mesoporous polystyrene monoliths. These are readily accessible by a mild hydrolysis reaction of a poly(styrene-b-lactic acid) precursor (see picture)
Density functional theories such as the Poniewierski–Stecki theory relate the elastic properties of \nnematic liquid crystals with their local liquid structure, i.e., with the direct correlation function \n~DCF! of the particles. We propose a way to determine the DCF in the nematic state from \nsimulations…
We have investigated the conductivity and photoconductivity response of undoped and Li-doped ZnGa2O4 epitaxial films grown using pulsed-laser deposition. A significant enhancement of the ultraviolet (UV) photoresponse is observed with Li doping that also correlates with an enhanced luminescent intensity. The wavelengt…
Hydrolysis of the new metallorganic precursor Fe(OBut)2(THF)2 followed by ultrasound and thermal treatment yielded either nanoparticles of γ-Fe2O3 or Fe3O4, depending on the process conditions. The samples have been characterised by X-ray powder diffraction, TEM, SEM, Mössbauer spectroscopy and magnetization measureme…
Fullerene-like CNx (x≈0.12) thin solid films were deposited by reactive magnetron sputtering of graphite in a nitrogen and argon discharge on cleaved NaCl and Si(001) substrates at 450 °C. As-deposited films consist of 5 nm diam CNx nano-onions with shell sizes corresponding to Goldberg polyhedra determined by high-re…
The field emission from aligned multiwalled carbon nanotubes prepared by thermal chemical vapor deposition of Fe-phthalocyanine is reported, with emphasis on the current–voltage characteristics and current fluctuation. By running of a pristine emitter at high current and/or voltage for a long time, the onset voltage i…