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 question as to how zeolites are able to hold tightly bound ions is answered. We show that zeolite frameworks can support whole bands of rigid unit modes (floppy modes) in k space and hence show that localized rigid unit modes can form within such frameworks that do not distort the constituent tetrahedra to any sig…
The width of the interface between two immiscible polymers, deuterated polystyrene and poly(methyl methacrylate), has been measured using neutron reflectivity as a function of the thickness of the deuterated polystyrene layer. A logarithmic dependence of interface width on film thickness is observed, characteristic of…
We investigate island formation during heteroepitaxial growth using an atomistic model that incorporates deposition, activated diffusion, and stress relaxation. For high misfit the system naturally evolves into a state characterized by a narrow island size distribution. The simulations indicate the existence of a stra…
The dissociative adsorption of hydrogen on Pd(100) has been studied by ab initio quantum dynamics and ab initio molecular dynamics calculations. Treating all hydrogen degrees of freedom as dynamical coordinates implies a high dimensionality and requires statistical averages over thousands of trajectories. An efficient…
We present a theory for the damping of layer-by-layer growth oscillations in molecular beam epitaxy. The surface becomes rough on distances larger than a layer coherence length which is substantially larger than the diffusion length. The damping time can be calculated by a comparison of the competing roughening and sm…
The electronic structure of the 4d transition-metal oxide PdO is investigated by photoemission (UPS and XPS), inverse photoemission (BIS; ), and electron energy loss spectroscopy in reflection geometry (REELS; primary energy, ). The valence band spectra are compared to recent theoretical ab initio band-structure calcu…
We have investigated the shear flow of a polydimethylsiloxane (PDMS) melt on a PDMS brush of well-controlled density. As the shear rate, γ̇, is increased, we show the existence of a slip transition from a weak slip regime, where the extrapolation length of the velocity profile, b , is a constant b 0 , to a strong one,…
Theoretical investigation of the magnetisation process in high-spin cluster is performed. The source of hysteresis is studied; magnetisation jumps on hysteresis loops of a cluster corresponding to intersections of energy levels are described theoretically. An analytical formula for the dependence of the height of a ju…
We present the results of a detailed study of the high‐pressure behavior of anorthite (CaAl 2 Si 2 O 8 ) between ambient pressure and 30 GPa under static conditions, using in situ Raman spectroscopy and energy‐dispersive X ray diffraction. On increasing pressure under hydrostatic conditions, the transition occurs firs…
We derive an explicit Hamiltonian for copying the basis up and down states of a quantum two-state system - a qubit - onto n "copy" qubits initially all prepared in the down state. In terms of spin components, for spin-1/2 particle spin states, the resulting Hamiltonian involves n- and (n+1)-spin interactions. The case…
The structure/electrical resistivity relationship in CB-loaded immiscible HIPS/LLDPE blends was studied. Effects of CB content and location, dispersed polymer phase size and shape, dispersed phase viscosity, and processing procedures were examined. The elongated dispersed phase in CB-containing blends is essential for…
Tensile mechanical properties of poly(aryl ether ether ketone) (PEEK) films showing different thermal histories have been investigated at room temperature to point out the main key microstructural features governing properties over a wide strain rate range, i.e., from 10−5 to 300 s−1. The strain rate sensitivity of th…
Cyclic voltammograms of pyrrole monomer and polypyrrole films prepared potentiostatically at 1.0 V versus an Ag/AgCl electrode have been examined. The insulating natural fibers, such as cotton, silk, and wool become electrically conducting when they are subjected to electrical treatment in the polymerizing solution of…
Ordering of Mn3+ and Mn4+ ions occurs in the rare earth manganates of the general composition Ln(1-x)A(x)MnO(3) (Ln rare earth, A = Ca, Sr). Such charge-ordering is associated with antiferromagnetic and insulating properties. This phenomenon is to be contrasted with the ferromagnetic metallic behavior that occurs when…
Plasma polymerization of silane compounds has been discussed for deposition of SiOx positron emission tomography (PET) films at room temperature. A mixture of tetramethoxysilane (TMOS) and oxygen containing 60 mol % O2 is a preferable raw material for SiOx formation by plasma polymerization. The deposited plasma polym…
Partial Contents: 1. Transformation of Dislocations. Dislocation Description of a Phase Transformation Front. 2. Dislocation Theory of Elastic Twinning. Twinning of Crystals: Principal Definitions. 3. Statics and Dynamics of Elastic Twinning. Discovery of Elastic Twinning. Verification of the Validity of the Static Th…
The mechanical behavior of films cast from sugar beet cellulose microfibrils was investigated through tensile tests. The obtaining of these microfibrils by chemical and mechanical treatments from the raw beet pulp is described. Depending on their purification level, individualization state, and moisture content, diffe…
The mechanical behavior of films cast from sugar beet cellulose microfibrils was investigated through tensile tests. The obtaining of these microfibrils by chemical and mechanical treatments from the raw beet pulp is described. Depending on their purification level, individualization state, and moisture content, diffe…
Hexagonal and cubic phases of manganese oxide mesoporous structures (MOMS) have been prepared by means of the oxidation of Mn(OH) 2 . The hexagonal MOMS materials form a hexagonal array of pores with an open porous structure, thick walls (1.7 nanometers), and exceptional thermal stability (1000°C). The walls of the me…
Mesoporous silica materials containing functionalized organic monolayers have been synthesized. Solid-state nuclear magnetic resonance suggests that a cross-linked monolayer of mercaptopropylsilane was covalently bound to mesoporous silica and closely packed on the surface. The relative surface coverage of the monolay…