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 static dielectric constant $\ensuremath{\epsilon}$ of KTa${\mathrm{O}}_{3}$ has been measured from 4 to 300K and at pressures up to 26kbar. The temperature ${T}_{1}$ at which $\ensuremath{\epsilon}$ deviates from a Curie-Weiss law, attributed to quantum effects, is found to increase with increasing pressure with a…
The method of tight binding has been applied to calculate the energy band structure of the lithium fluoride crystal. As initial approximations to the ultimate self-consistent---field (SCF) calculations, two different overlapping atomic potentials were employed, one formed by a superposition of the potential of the neu…
We have observed strong anharmonic coupling between the pseudospin "tunneling" mode and an optical mode of ${\ensuremath{\beta}}_{2}$ symmetry in the paraelectric phase of cesium dihydrogen arsenate. At temperatures above ${T}_{c}=143$ \ifmmode^\circ\else\textdegree\fi{}K this interaction is manifest as an antiresonan…
Photoemission and secondary electron emission (SEE) measurements have been used to investigate the band structure of graphite. The energy distribution curves obtained from both types of measurements reveal identical features for those transitions to conduction-band states occurring up to 5 eV above the vacuum level. T…
Using both infrared and laser Raman techniques the low temperature vibrational spectra of KBH 4 , KBD 4 , NaBH 4 , and NaBD 4 have been recorded. The spectra of the external lattice vibrations are consistent with the following borohydride ion site symmetries: T d for potassium borohydride and D 2d for sodium borohydri…
Some electronic defects and the associated photoelectronic processes in Th${\mathrm{O}}_{2}$ are analyzed by utilizing the data from thermoluminescence (TL) and EPR measurements on a number of rare-earth-doped and undoped single crystals from various sources. (The EPR measurements were made by others.) Some fluorescen…
For the first time, phosphorescence has been observed from and clearly assigned to the molecular triplet of several metallophthalocyanine (Pc) molecules. The Pc's of Pt, Pd, Cu, Zn, and Cd have O–O bands in solution (77°K) at the extraordinarily low energies of 10 590, 10 100, 9390, 9150, and 9120 cm−1, respectively,…
Using a simple Hamiltonian of the tight-binding type, rigorous bounds are derived for the density of states of a tetrahedrally bonded solid. These include inner bounds which define a band gap between occupied and unoccupied states. The derivation uses only the assumed perfect coordination of nearest neighbors, and so…
The energy distribution and angular dependence of secondary electrons generated by the impact of 100–2000-eV electrons on He, N2, and O2 and by the impact of 500-eV electrons on Ne, Ar, Kr, Xe, H2, NO, CO, H2O, NH3, CH4, C2H2, and CO2 have been measured over the 4–200-eV range. The measurements were made in a crossed-…
Dispersion relations of phonons propagating along three symmetry directions in calcium oxide have been measured by the triple axis neutron spectrometer method. The experimental results have been interpreted in terms of a shell model showing that the electronic polarizability of both ions must be taken into considerati…
Measurements are reported of photoluminescence from three defect centres in diamond which have characteristic absorption and emission lines at 1.673 eV, 1.944 eV and 2.498 eV respectively. When excited with plane polarized light the emission from the 1.673 eV centre was found to be unpolarized in agreement with a cent…
In the system (${({\mathrm{V}}_{1\ensuremath{-}x}{\mathrm{Ti}}_{x})}_{2}{\mathrm{O}}_{3}$, the antiferromagnetic insulating phase is suppressed for $x>0.05$. The linear term in the heat capacity is very large ($\ensuremath{\gamma}=192\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}$ cal \ifmmode^\circ\else\…
Abstract The magnetic field at the site of the nuclei 152 Sm and 154 Sm in a ferrimagnetic Sm 6 Mn 23 probe has been measured by means of the perturbed angular correlation method after Coulomb excitation. The temperature dependence of the magnetic field has been investigated and compared with the results of macroscopi…
Un atome irradié par des photons non résonnants peut les absorber et réémettre virtuellement ; il est en quelque sorte "habillé" par les photons du champ électromagnétique dans lequel il est plongé. Nous montrons dans cet article comment les propriétés physiques d'un atome "habillé" par des photons optiques ou de radi…
The Boltzmann transport equation is solved taking into consideration the skew scattering of carriers in a magnetic semiconductor. The conductivity tensor is derived and used in the study of the spontaneous Hall effect. The effect of anisotropic scattering and spin-orbit interaction usually present in magnetic metals i…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTDependence of the glass transition temperature on heating rate and thermal historyCornelius T. Moynihan and Pedro B. MacedoCite this: J. Phys. Chem. 1971, 75, 21, 3379–3381Publication Date (Print):October 1, 1971Publication History Published online1 May 2002Published inissue…
Abstract Da katalytische Untersuchungen mit atomar verteilten Metallen neue experimentelle Methoden erforderlich machten, wird zunächst be‐richtet über die Methoden zur genauen Dosierung von Nickel‐ und Palladiumbelegungen Θ Me ≥ 10 −2 auf im Ultrahochvakuum hergestellten Kohlenstoffilmen sowie über das spezielle Mass…
Magnetic measurements were made of the systems (Cr 1.01 Sb) 1- x (Fe 1.22 Sb) x and (Cr 1.01 Sb) 1- x (Co 1.13 Sb) x . In both systems, ferromagnetism appeared in the intermediate range of x . In the (Cr, Fe)Sb system maximum of the spontaneous magnetization and the Curie temperature was found at x =0.6. However, the…
Abstract An approximate method is described for calculating electrostatic fields of rotational symmetry with arbitrary boundary conditions. The method is based on the computation of the surface charge density on the field forming electrodes. Successfully tested by well-known analytical solutions, the method is applied…
Piezoelectric lithium formate monohydrate crystallizes in the orthorhombic system with a tetramolecular unit cell of dimensions a = 6.504 (10), b = 9.989 (10), c = 4.856 (5) Å in the space group Pbn21. The crystal structure has been solved by vector superposition methods and refined to an R value of 10.3 % for 331 obs…