Materials Literature
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(Ba0.5Sr0.5)TiO3 thin films were prepared by ion beam sputtering from powder targets with (Ba+Sr)/Ti ratios ranging from 0.80 to 1.50. All of the perovskite (Ba,Sr)TiO3 films were single phase except for the film with a (Ba+Sr)/Ti ratio of 1.41. The dielectric constant values notably depended on the (Ba+Sr)/Ti ratio f…
A negative dielectric anisotropy cholesteric liquid crystal, oriented homeotropically in a wedged capacitance cell, was subjected to an applied electric field. The Freedericksz transition threshold voltage was found to depend on the local thickness of the sample, and was found to vanish at a thickness of order 3/2 P,…
The enhancement of acoustic caviation at a liquid-solid interface following laser-induced bubble formation is studied. The experiment results indicate that metastable ultramicroscopic bubbles formed on the solid surface cause a long-term ``memory effect'' on acoustic cavitation. By performing a double-pulse experiment…
Abstract The chemical crosslink density (CLD) and network structure of natural rubber (NR) vulcanizates, modified with phosphorylated cardanol prepolymer (PCP), have been studied by equilibrium swelling and other chemical methods. The PCP‐modified NR vulcanizates showed lower CLD, as compared to the unmodified NR samp…
Hydrofluoric acid solutions containing high concentrations of the ion NO+ produce an etchant capable of reproducibly generating a porous silicon layer on both single-crystal and polycrystalline silicon surfaces. Room-temperature photoluminescence from porous silicon that has been chemically etched in such solutions ha…
The concentration fluctuations induced in a semidilute polymer solution by shear flow are directly visualized for the first time. The spatial structure of the ``butterfly pattern'' observed by light scattering is elucidated, being the result of hydrodynamic rippling waves which have a distribution of tilt angles. The…
Abstract The crystalline structure of chitosan membranes made of a high degree of (90%) and low degree of (60%) deacetylated chitin by various regeneration processes was studied. The results of X‐ray and IR spectroscopy investigations testify that the type of crystalline structre, the degree of crystallinity, and the…
Components of the extracellular matrix are believed to guide both nerve cells and neurites to their targets during embryogenesis and, therefore, might be useful for controlling regeneration of nervous tissue in adults. To study the influence of extracellular conditions on neurite outgrowth and cell motility, PC12 cell…
This paper analyses instabilities on the cryolite/aluminium interface in an aluminium reduction cell. The simplified cell model is a finite rectangular tank containing the two fluid layers, and carrying a uniform normal current. The magnetic field is assumed to be a linear function of position. Several previous studie…
Systems that use light as a carrier of information \noffer the possibility of extremely \nhigh speed processing, transmission, and \nstorage of data. Many such photonic systems \nrequire high-performance nonlinear \noptical (NLO) materials (1, 2), particularly \nthose exhibiting second-order NL…
Previous high-resolution electron microscopy (HREM) observations of the carbon nanotubes have led to a "Russian doll" structural model that is based on hollow concentric cylinders capped at both ends. The structures of the carbon nanotubes and particles were characterized here by bulk physical and chemical property me…
The interaction of polymers with their environment depends largely on the functional groups they carry. Interfaces between different polymers or between polymers and other surfaces can be strengthened through the design of molecular interactions such as hydrogen bonding and through the control of polymer architecture.…
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” opt…
The thermal energy flux which a rf plasma delivers to a silicon surface has been studied by a calorimetric method. The energy flux appears to be proportional to the product of the average ion energy and the ion flux, which was calculated from the Bohm criterion using measured plasma parameters. Furthermore, the value…
The optical conductivity of high quality decagonal quasicrystals of ${\mathrm{Al}}_{65}$${\mathrm{Co}}_{17}$${\mathrm{Cu}}_{18}$ and ${\mathrm{Al}}_{62}$${\mathrm{Co}}_{15}$${\mathrm{Cu}}_{20}$${\mathrm{Si}}_{3}$ shows a strong anisotropy between the periodic and the quasiperiodic directions. We suggest that this is d…
A survey of the published data on the type of anchoring (homeotropic, planar or tilted) of nematic liquid crystals on Langmuir-Blodgett (LB) films of charged and dipolar amphiphiles, as a function of surface density of molecules and number of molecular layers in the film, reveals a complex and seemingly controversial…
The magnetic a and c axes are switched by applying high magnetic field in ${\mathrm{DyCu}}_{2}$ single crystal. The virgin state has the Ising axis along the a direction with the two-step metamagnetism but the Ising axis is switched to the c direction by applying the field higher than 13 T along the c axis. The recove…
It has recently been observed that a diblock copolymer melt can undergo a second microphase separation with increasing temperature. We use an equation-of-state description along with the random phase approximation to study the stability of the disordered system, and calculate the lower critical ordering temperature as…
Abstract Graft copolymerization of spiropyran‐containing methacrylate (SPMMA) and acrylamide (AM) onto the surface of a porous polymer membrane was carried out. The permeability of the graft membrane varied with ultraviolet (UV) ‐ or visible‐light irradiation. It was found that the change by UV‐light irradiation of th…
Diamond films are predominantly grown using approximately 1% of a hydrocarbon precursor in hydrogen gas. Hydrogen is generally believed to be necessary for the diamond thin-film growth process. However, hydrogen in varying amounts is inevitably incorporated in the growing diamond lattice, leading to structural defects…