Materials Literature
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Electrical failure of carbon nanotubes was investigated by obtaining I(V) data with a voltage ramp from a rope of multiwalled carbon nanotubes. Noncontact scanning force microscope images were obtained before and after each I(V) curve until electrical failure of the tube resulted. Following this procedure, it was poss…
Spherical morphology BN powders have been produced in a two-step process. The first step involves drying and partial nitridation of a H3BO3/H2O aerosol at 1000 °C with an ammonia/nitrogen gas stream followed by final nitridation at 1700 °C with ammonia.
The cross-linking low-dielectric-constant polymers benzocyclobutene (BCB) and perfluorocyclobutene (PFCB) are identified as film electrets with excellent charge stability, comparable to the members of the polytetrafluoroethylene family. BCB and PFCB films can be easily prepared on substrates by spin coating. The onset…
The simultaneous regulation of mechanical properties and permeability, for a new microcapsule based on the complexation of oligochitosan and alginate, is possible through control of the reaction conditions. Specifically, the results of mechanistic study have shown that the molar mass of the polyanion influences primar…
Recent years, Prof. Cheng Kaijia raised and developed a new electron theory based on the first principles, which is called as TFDC by researchers in China. The theory clearly exponnds the important role of boundary conditions of electron. It has been successfully applied and some valuable results have been obtained, w…
The elastomers of polyvinyl alcohol gel were made from the polyvinyl alcohol polymer, with boric acid added as a crosslinking agent, in the mixed solvent of dimethyl sulfoxide and water. From the experimental results, the viscosity of polyvinyl alcohol solution is found to increase not only with an increment of boric…
Structure and mechanical properties were studied for the binary blends of a linear low density polyethylene (LLDPE) (ethylene-1-hexene copolymer; density = 900 kg m−3) with narrow short chain branching distribution and a low density polyethylene (LDPE) which is characterized by the long chain branches. It was found by…
Ion exchange of Pd(II) ions into a nanostructured lyotropic liquid crystal network, followed by reduction with hydrogen gas, generates a polymer composite containing finely dispersed, catalytically active Pd nanoparticles 4−7 nm in diameter. Loss of order upon nanoparticle growth appears to be due to residual mobility…
We investigate a binary Lennard-Jones mixture with molecular dynamics simulations. We consider first a system cooled linearly in time with the cooling rate gamma. By varying gamma over almost four decades we study the influence of the cooling rate on the glass transition and on the resulting glass. We find for all inv…
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…