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。
Potassium niobate (KNbO 3 ) ceramics are usually porous due to their poor sinterabilty under ordinary firing in air, although the single crystal exhibits a large amount of piezoelectricity. We found a marked improvement in the sinterability of KNbO 3 ceramics on substituting a small amount of Pb for K. However, the am…
Defect engineering to design for remanent polarization ( P r ) and coercive field ( E c ) in SrBi 2 Ta 2 O 9 (SBT) is proposed. Cation vacancies coupled with substituents or oxide vacancies are shown to play an essential role in determining the polarization properties. High-resolution neutron powder diffraction studie…
To reveal the influence of lattice defects on electrical conduction of bismuth titanate (Bi 4 Ti 3 O 12 : BIT), one of the bismuth layer structured ferroelectrics, changes in lattice parameters and weight by high-temperature annealing and the dependence of conductivity on oxygen partial pressure ( P o 2 ) were examine…
In the search for high-performance piezoelectrics, (1- y )(Na 0.5 K 0.5 )NbO 3 – y PbTiO 3 ( y ≤0.50) solid solution has been prepared using the spark-plasma-sintering method. Dielectric investigation reveals that both the ferroelectric phase transition temperatures and the peak value of the dielectric constant are st…
The review surveys synthetic approaches to spiro[1,4]oxazines belonging to one of the most promising classes of organic photochromes. The relationships between the structures of spirooxazines and their spectral properties as well as characteristics of thermal and photoinduced processes are considered. The bibliography…
Fine-grained dielectric ceramics, i.e., of 0.2 µm grain diameter, were obtained using Ca-doped BaTiO 3 powders consisting of particles 0.2 µm in diameter. The (Ba 1- x Ca x ) m TiO 3 ceramics ( x : 0–0.10, m : 1.003–1.009) showed a high dielectric constant and stable temperature dependence, which were provided by inte…
High-speed observations clearly show that though a collapsing cavitation bubble approaches its minimum size as a coherent single volume, it usually reappears in the first rebounding frame as a cloud of much smaller bubbles or as a highly distorted single volume. This paper explores two mechanisms that may be responsib…
The current status of research and development in the realm of physics and technology of collective ion acceleration in systems with a virtual cathode (VC) is reviewed. Three major acceleration methods and devices developed on their basis are considered: reflex triodes and their modifications, gas-filled vircators, an…
In this paper, spiral symmetry in cylindrical coordinate and general Bloch's theorem induced from it are discussed. This general Bloch's theorem is useful for considering the properties related to single-walled carbon nanotubes.
Two single-molecule magnets are coupled antiferromagnetically to form a supramolecule dimer. We study the coupling effect and tunneling process by means of the numerical exact diagonalization method, and apply them to the recently synthesized supramoleculer dimer [Mn4]2 The model parameters are calculated for the dime…
A Comment on the Letter by Granger et.al., Phys. Rev. Lett. 89, 135506 (2002).
The photophysical properties of a supramolecular donor-acceptor dyad consisting of an oligo(p-phenylenevinylene) unit and a perylene-diimide unit are described. The dyad is created by functionalising the two chromophores with quadruple hydrogen bonding 2-ureido-4[1H]-pyrimidinone units, which provide a high associatio…
With open-structure (nanoporous) oxidic solids, numerous distinct kinds of single-site catalysts may be precisely designed. Apart from serving as a means of generating a range of powerful new catalysts (especially for selective oxidations), in which well-defined active sites are carefully engineered, the detailed loca…
Disordered granular systems, at temperatures where charging effects are important, are studied, by means of an effective medium approximation. The intragrain charging energy leads to insulating behavior at low temperatures, with a well defined Coulomb gap. Non equilibrium effects can give rise to a zero temperature tr…
We demonstrate that GaMnAs films grown with As2 have excellent structural, electrical and magnetic properties, comparable or better than similar films grown with As4. Using As2, a Curie temperature of 112K has been achieved, which is slightly higher than the best reported to date. More significantly, films showing met…
The plastic deformation of a quasicrystal (QC) is ruled by singularities of its 'phonon' strain field and of its 'phason' strain field. In the framework of the topological theory of defects, and the QC being defined as an irrational subset of a high dimensional crystal, both types of defects appear as distinct compone…
In the book "Ferroelectric and Antiferroelectric Liquid Crystals" by S. T. Lagerwall, the concept "polar liquid crystals" is proposed for the concept earlier known as "ferroelectric liquid crystals", reserving the word "ferroelectric liquid crystals" for the case of "surface stabilization". Thus Lagerwall in this way,…
The dynamical properties of the high-density Ru(001)-(1$\times$1)-O phase has been investigated by a combined high-resolution electron energy loss spectroscopy and density functional theory study. Due to a strong static outward relaxation of the first Ru layer a soft Rayleigh phonon mode is expected. However, a Raylei…
The magnetoresistance in a series of Ga1-xMnxAs samples with 0.2 =< x =< 0.8 have been measured for three mutually orthogonal orientations of the external magnetic field. The anisotropy magnetoresistance decreases with increasing of the Mn content, which means that the magnetic disorder or defects scattering increases…
Fluorescent semiconductor nanocrystals (quantum dots) have the potential to revolutionize biological imaging, but their use has been limited by difficulties in obtaining nanocrystals that are biocompatible. To address this problem, we encapsulated individual nanocrystals in phospholipid block-copolymer micelles and de…