Materials Literature
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We study the Mott transition in Hubbard models with a degenerate band on different 3-dimensional lattices. While for a non-degenerate band only the half-filled system may exhibit a Mott transition, with degeneracy there can be a transition for any integer filling. We analyze the filling dependence of the Mott transiti…
Magnetization hysteresis loop $M(H)$ measurements performed on a single crystalline Ba$_{0.63}$K$_{0.37}$BiO$_3$ superconducting thick film reveal pronounced sample geometry dependence of the "second magnetization peak" (SMP), i.e. a maximum in the width of $M(H)$ occurring at the field $H_{\rm SMP}(T)$. In particular…
This paper presents a review of the phenomenon of interlayer exchange coupling in magnetic multilayers. The emphasis is put on a pedagogical presentation of the mechanism of the phenomenon, which has been successfully explained in terms of a spin-dependent quantum confinement effect. The theoretical predictions are di…
We describe how density-matrix renormalization group (DMRG) can be used to solve the full-CI problem in quantum chemistry. As an illustration of the potential of this method, we apply it to a paramagnetic molecule. In particular, we show the effect of various basis set, the scaling as the fourth power of the size of t…
We report a high-yield route to two-dimensional arrays (<400×400 μm2) of aligned C49Nx (x⩽1) nanofibers (<100 nm o.d.; <60 μm length), by pyrolyzing mixtures of ferrocene and melamine at 950–1050 °C under an Ar flow. The fibers exhibit unusual interlinked stacked-cone morphologies, ascribed to the…
Influence of oxygen pressure on the epitaxy, surface morphology, and optoelectronic properties has been studied in the case of ZnO thin films grown on sapphire (0001) by pulsed-laser deposition. Results of Rutherford backscattering and ion channeling in conjunction with atomic force microscopy clearly indicate that th…
The extent of flattening of poly(butyl methacrylate) (PBMA) latex film surfaces was determined using the atomic force microscopy (AFM) technique and compared with the extent of polymer chain migration between adjacent particles in the film, which was determined by the nonradiative energy transfer (NRET) method. The fi…
[structure: see text] An efficient and potential stepwise strategy involving the mixed sequence of Stille and Wittig-Horner reactions was used for the preparation of a polyene-substituted bis-porphyrin incorporating a bipyridine moiety.
A Fourier transform infrared spectroscopy investigation relative to clathrate forms of syndiotactic polystyrene (s-PS) with chlorinated organic compounds is presented. In particular, for 1,2-dichloroethane (DCE), 1,2-dichloropropane (DCP), and 1-chloropropane (CP), the absorption peaks which are modified as a result o…
Fluoropolymers exhibit a number of favorable properties such as high-temperature stability, chemical resistivity, and a low surface energy. However, the possibility to incorporate fluoropolymers into other materials is limited because of the low surface energy. Modification procedures such as radiation modification ca…
Single flat-elongated and helical lamellar crystals have been grown thermotropically in a main-chain nonracemic chiral liquid crystalline polymer that was synthesized from ( R )-(−)-4‘-{ω-[2-( p -hydroxy- o -nitrophenyloxy)-1-propyloxy]-1-nonyloxy}-4-biphenyl carboxylic acid, PET(R*)-9. The crystals possess the identi…
Photophysical properties of 10 substituted methoxybenzene or vinyl linked benzo-crown-ether−2,2‘-bipyridyl ruthenium(II) complexes are reported. The lifetimes of the excited triplet metal to ligand charge transfer states, 3 MLCT, of the complex ions are in the range 0.85 ± 0.12 μs with two exceptions where the lifetim…
The adsorption of calf thymus DNA to 45 Å nanoparticles of Cd(II)-rich CdS has been examined by photoluminescence spectroscopy as a function of temperature. The resulting van't Hoff plot suggests that the driving force for adsorption is entropy, and the enthalpic contribution to DNA−surface binding is slightly unfavor…
Several members of the RNase A superfamily are endowed with antitumor activity, showing selective cytotoxicity toward several tumor cell lines. One of these is onconase, the smallest member of the RNase A superfamily, which is at present undergoing phase III clinical trials. We report here the expression of recombinan…
Trivalent methyl and vinyl samarium derivatives supported by the calix-tetrapyrrole ligand system (Et 8 -calix-pyrrole)(R)Sm(μ 3 -Cl)[Li(THF)] 2 [Li(THF) 2 ] [R = Me ( 2a ), CH CH 2 ( 2b )] were prepared via reaction of (Et 8 -calix-pyrrole)(Cl)Sm[Li 2 (THF) 3 ] ( 1 ) with the corresponding organolithium reagent. Comp…
Five generations of carboxylate-functionalized poly(propyleneimine) dendrimers have been synthesized starting from a double Michael addition of amine-functionalized poly(propyleneimine) dendrimers to methyl acrylate followed by basic hydrolysis using LiOH in a water/methanol mixture. The dendritic compounds have been…
PbSe nanoparticles of about 12 nm in size have been prepared by a pulse sonoelectrochemical technique from an aqueous solution of sodium selenosulfate and lead acetate. The PbSe nanoparticles were characterized, using techniques such as transmission electron microscopy, X-ray diffraction, absorption spectroscopy, diff…
The connection between friction and jamming in granular media, molecular glasses, and complex fluids is explored. The paper first reviews the way friction is measured, the types of results that are observed, and what is known about the geometry of contacts between macroscopic surfaces. Then simple models for the origi…
Laser Raman spectroscopy (LRS), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), ultraviolet and visible diffuse reflectance spectroscopy (UV-DRS), and temperature-programmed reduction (TPR) are used to characterize a series of WO 3 /CeO 2 samples. The r…
The differences in the fluorescence behavior of a polyphenylene dendrimer with eight peryleneimides chromophores (1) and a single hexaphenylperyleneimide chromophore have been investigated at a single-molecule level through the combination of ultrasensitive fluorescence detection and microscopy.