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。
We present a theoretical investigation about the role played by spatial correlation among nuclei in the kinetics of first-order phase transitions. From the cluster expansion of the distribution functions in terms of the m-dots correlation functions, we obtain the equation which describes the kinetics in case of simult…
Heat treatment was performed on β‐SiC with different sintering additives in the temperature range 1873–2073 K, in both argon and nitrogen‐gas atmospheres. In the case of the specimens heat‐treated at 2073 K in argon, the weight loss was more than the total weight of the sintering additives, except for B,C‐doped β‐SiC.…
The coexistence of ferromagnetism and metallic conduction in doped manganites has long been explained by a double exchange model (ferromagnetic Kondo-lattice model) in which the ferromagnetic exchange arises from the carrier hopping. We evaluate the zero-temperature spin stiffness $D(0)$ and the Curie temperature ${T}…
The polaron-ordered structure of ${\mathrm{La}}_{1\ensuremath{-}x}{\mathrm{Sr}}_{x}{\mathrm{MnO}}_{3} (x\ensuremath{\cong}\frac{1}{8})$ has been reinvestigated to verify the previously proposed models. We found satellite reflections on the ${(0,k,l)}_{\mathrm{ortho}}$ and ${(1,k,l)}_{\mathrm{ortho}}$ reciprocal planes…
The characterization of ink jet dyes and inks printed onto paper surfaces is of importance for the development of ink jet ink formulations and for use in forensic science. Raman spectroscopy is an effective and informative probe for this purpose if problems associated with fluorescence are overcome. A comparison is ma…
Organic conductors based on the bis(ethylenedithio)tetraselenafulvalene(BETS) are of interest because they display not only superconducting and magnetic transitions but also, as recently reported, unprecedented superconductor to insulator transitions. Here is presented the electrical and magnetic properties for two se…
Abstract Diarylperfluorocyclopentenes having 2-isopropyl-5-phenylthiophene and 2-isopropyl-1-benzothiophene aryl groups underwent thermally reversible photochromism in solution. The photogenerated colored closed-ring isomers returned to the initial colorless open-ring isomers above 60 °C. The activation energies of th…
Abstract A unique catalyst, Au core and Pd shell bimetallic nanoparticles immobilized on porous silica exhibiting a considerable high activity for the hydrogenation of cyclohexene, was prepared via two steps composed of the sonochemical reduction method and the sol–gel process under a low temperature condition.
A range of 5,15-diphenylporphyrins with symmetric and unsymmetric substitution patterns were subjected to osmium tetroxide-mediated dihydroxylations. The resulting chlorins and bacteriochlorins present an important group of compounds for studying structure-activity relationships of photodynamic sensitizers. The regios…
The formation and restoration of defects by F2 laser irradiation with high laser fluence were investigated for modified silica glasses, and the results were compared with those by ArF excimer laser irradiation. F2 laser irradiation induced oxygen deficient centers (ODCs) and E′ centers via one-photon-absorption proces…
Abstract The fracture behavior of elastomers has been studied in the high speed region immediately above a transition region where a change in the nature of the fracture surface occurs. A video camera operating at up to 6000 frames/s was used to follow the progress of failure. The test pieces employed were of the pure…
This paper deals with regular arrays of macroscopic defects (focal conic domains) observed when a slab of lamellar phase is sandwiched between two substrates imposing different orientational anchorings. We report, in particular, detailed observations of the texture of a lyotropic lamellar phase in contact with a glass…
Macropore formation on medium doped p-type silicon with a doping density as high as [Na] = 1017 cm—3(ρ= 0.2 Ωcm) was observed for the first time. As this occurs only in presence of N,N-dimethylformamide and dimethylsulfoxide, it is assumed that the nature of the organic solvent plays an important role in the dissoluti…
Three series of dimer liquid crystals containing an aromatic and a cholesteryl mesogenic unit were synthesized and investigated The compounds within the series differ in the length of the spacer connecting the mesogenic groups. Two of the three series contain an aromatic mesogenic group that is connected to the spacer…
Various aromatic polybenzoxazole (PBO) films were prepared through the two-step silylation method by low-temperature solution polycondensation of trimethylsilyl-substituted bis(o-aminophenol)s with aromatic dicarboxylic acid chlorides yielding precursor poly(o-trimethylsiloxy-amide)s, followed by thermal cyclocondensa…
Sorption and desorption processes of cationic dyes occurring in single silica gel microparticles in an aqueous solution were kinetically studied by microcapillary manipulation/injection and microabsorption methods. The sorption and desorption rates of rhodamine 6G were limited by diffusion of the dye in the particle i…
The composition (% relative abundance) of the benthic diatom community was studied in the littoral zone (0–5 m) of the NW and E coasts of the brackish, non-tidal Gulf of Riga, in the Baltic Sea. The samples were collected concomitantly with measurements of sediment primary productivity and chlorophyll a during three c…
Abstract The control of crystallization is important at all processing stages of the PET bottle industry, from the manufacture of bottle resins to the fabrication of preforms and bottles. In this work, we sought to evaluate critically three methods of crystallinity measurement. We have used density, Differential Scann…
Consolidation of aqueous concentrated suspensions was used to shape alumina green bodies because it enabled us to obtain complex‐shape components with accurate sizes. A high state of alumina particle dispersion was achieved by using (HO) 2 C 6 H 2 (SO 3 Na) 2 (Tiron), which allowed us to obtain stable alumina suspensi…
Strong retardation of photovoltage transients has been observed in porous materials (meso- and nanoporous Si, sintered networks of TiO2 nanoparticles, porous Al oxide) excited by short laser pulse. It has been shown that the photovoltage is mainly determined by the slow carriers diffusion with different diffusion coef…