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。
The mechanical properties of Si 3 N 4 /SiC nanocomposite materials that contained nanosized intercrystalline SiC dispersions that originated from different starting powders and were made via different fabrication routes were studied in the temperature range of 1400°‐1550°C. The strength retained at 1400°C was between…
Excellent candidates for high remanent permanent magnets are nanoscaled composite materials consisting of soft magnetic $\ensuremath{\alpha}$-Fe grains embedded into a hard magnetic ${\mathrm{Nd}}_{2}{\mathrm{Fe}}_{14}\mathrm{B}$ environment. The magnetic properties of such permanent magnets sensitively depend on the…
The interaction of oxygen with the ordered Ni3Al (111) surface has been investigated in the temperature range from 300 to 1000 K using high-resolution electron-energy-loss spectroscopy (HREELS) and low-energy electron diffraction (LEED). The “2×2” LEED pattern of the clean Ni3Al (111) surface indicates a bulklike term…
Three-dimensional (3D) simulations of meso-phase formation in block copolymer melts under simple steady shear are performed in the framework of dynamic density-functional theory. The most stable ``perpendicular'' lamellar ordering is observed. The difference between 2D and 3D ordering in a model system is described. L…
Silver sulfide Ag 2 S nanocrystals have been synthesized in reverse micelles and coated with thioalkyl chains with different lengths. With short chains (≤C 8 ) and very long ones (≥C 16 ) the particles cannot be extracted from micelles. For short alkyl chains, this is due to disorder at the interface. For longer chain…
The fabrication of dense Si 3 N 4 /SiC nanocomposite materials that contained 2.5‐30 wt% SiC via gas‐pressure sintering and hot pressing was investigated. The SiC particles originated from admixed commercial SiC powders, SiCN powders produced by plasma synthesis, in situ reaction pyrolysis of carbon‐coated Si 3 N 4 pa…
X-ray-absorption fine-structure measurements from the Mn and La $K$ edges of samples of ${\mathrm{La}}_{1\ensuremath{-}x}{\mathrm{Ca}}_{x}{\mathrm{MnO}}_{3}$ $(x=\stackrel{\ensuremath{\rightarrow}}{0}1)$ are presented as a function of temperature. In the insulating state, distortions of the Mn-O environment are found…
For applications of carbon nanotubes in electronic components site-specific assembly of nanotubes onto patterned substrates is required. The Figure shows, as an example, a surface modification that favors attachment of nanotubes to an electrode (Au/Pd). The adsorbed nanotube (gray) has a partial surfactant shell and t…
Abstract The crystal structures of rare-earth metal sesquisulfides and some related compounds (Tm 5 S 7 , Tm 8 S 11 , Tm 15 S 22 ) of orthorhombic or monoclinic symmetry with the mirror plane perpendicular to the translation of 3.7 Å – 4.1 Å have been studied using an analysis of close-packed atomic nets. The cation a…
We have found that a film of amorphous selenium exposed to simultaneous action of two different (Kr+ and Ar+) lasers whose photon energies are on different sides of the optical band gap, crystallizes more slowly than the one exposed to only one of the above. A decisive role of the polarization of the two laser beams h…
In this paper the physical mechanisms and fundamental methods of obtaining nanometer-size atomic clusters in semiconductors are discussed, along with the possibility of controlling the properties of these clusters and those of the resulting cluster-containing materials. A number of electronic properties of semiconduct…
Acoustic cavitation generates very large localized pressures and temperatures, and thus provides a mechanism whereby physical and biological effects are produced in a high-intensity acoustic field. In this work, we studied the influence of the temporal form of a pressure pulse waveform on the destructive effects of tr…
Abstract Electrically conductive elastomer foams were prepared by in situ vapor phase copolymerization of pyrrole and N‐methylpyrrole within preformed polyurethane foams. The conductive polymer is formed within the dense polymer phase of the foam, and the conductivity of the composite foam ranged from 10 −1 to 10 −7 S…
The first report of the structural parameters of amorphous GaAs produced by ion implantation, as determined with extended x-ray absorption fine structure measurements, is presented herein. Relative to a crystalline sample, the nearest-neighbor bond length and Debye–Waller factor both increased for amorphized material.…
Three polyurethane elastomers (PU) containing different hard/soft (h/s) segment ratios were prepared. The PUs were characterized using Gel Permeation Chromatography (GPC), DSC, Wide Angle X-ray Diffraction (WAXD). Dynamic Mechanical Thermal Analysis (DMTA), and Stress-controlled rheometry. The surface properties were…
Abstract The results of an ab initio structure determination of a series of CuO powder samples are reported. It is shown that the thermal treatment affects the peak broadening and overlapping and determines the possibility to get the cell size and the atomic positions. It is also demonstrated that the highest level of…
Through the systematic addition of B, C, and Fe, additive effects on the stacking fault formation and the morphology of the particles formed during reaction synthesis of β‐SiC were investigated in the present study. The whisker content of the synthesized product and the formation mechanism of whiskers were closely rel…
Abstract Powder X‐ray diffraction and cryo electron diffraction techniques supported by computer simulations were used to determine the secondary structures of the series of heteropoly acid (HPA) compounds Cs x H 4‐ x PVMo 11 O 40 · n H 2 O (0≤ x ≤4). The structures of the caesium salts (2≤ x ≤4) are simple cubic with…
Folding and unfolding of atomic layers has been performed at step edges of graphite using a scanning tunneling microscope. The technique consists of modulating the distance or bias voltage between the microscope tip and the sample when scanning selected areas. Calculation of the energies involved in the manipulations…
Amorphous magnetostrictive films of the composition (Tb0.27Dy0.73)0.3Fe0.7 have been prepared by ion-beam sputtering. The films have been subjected to a subsequent heat treatment for 10 min at various temperatures. Annealing temperatures to 550 °C result in a significant enhancement of the magnetostriction while the m…