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。
Raman spectra of polycrystalline samples of CH3NH3PbC13 were studied at between 80 and 300 K. An assignment of most of the observed bands is proposed. The first-order phase transitions previously detected at 172 and 179K were characterized: The spectral evolution and the mechanism proposed are in agreement with the th…
The calibration constants that link the peak-shift measured with X-rays to the macroscopic stress acting on the material are termed X-ray elastic constants. These terms contain both material parameters such as the elastic stiffness or compliance terms and configurational parameters caused by the Miller indices of the…
The environment around Li in a ${\mathrm{LiAlSiO}}_{4}$ glass has been studied by neutron scattering with isotopic substitution of Li and reverse Monte Carlo modeling. Li atoms are found in distorted tetrahedral sites which are edge-linked with ${(\mathrm{S}\mathrm{i},\mathrm{A}\mathrm{l})\mathrm{O}}_{4}$ tetrahedra a…
The “living” free radical polymerization of styrene in the presence of 2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPO) affords low polydispersity polystyrene (PS). The thermal instability of the linkage of the TEMPO group of the PS, however, restricts the processing possibilities of the resin. Therefore, different method…
A method was developed for calculating range spectra of charged particles after passing through an inhomogeneous structure whose thickness was comparable to the range of the incident particles. It was shown that the spectra are strongly affected by the influence of multiple Coulomb scattering at interfaces parallel to…
It is established that variable-range hopping conduction takes place between states localized near the Fermi level in layered TlGaS 2 and TlInS 2 single crystals both along and across their natural layers in a constant electric field at T ⩽200 K. The densities of states near the Fermi level and the hopping distances a…
Core and valence band spectra were obtained from a PbO2 sample. The XPS data were collected with a VSW HA150 spectrometer equipped with a monochromatic Al Kα x-ray source and a multichannel detector. This report includes the Pb 4f, Pb 5d, Pb 4d, O 1s, C 1s, and valence band photoemission peaks. The XPS analysis showed…
The authors calculate the capacitance of a pair of power transformer winding disks containing wound-in-shields by means of a simple formula and by means of a detailed circuit model. In addition, experiments were performed to check the formula under various conditions such as changing the number of shield turns and att…
We have prepared monodisperse suspensions of nematic liquid crystal droplets in water. The droplets are stabilized by polyvinyl alcohol, a polymer that induces planar anchoring of the liquid crystal molecules at the surface of the droplets. The resultant particles exhibit strong optical anisotropy while having a spher…
Cyclic polarization of TiN electrodes in 6 M KOH at room temperature revealed relatively large anodic and cathodic overpotentials for water decomposition that depend on the surface structure of the material. Polished TiN electrodes also underwent a slow reaction during anodic polarization above the reversible potentia…
Abstract Biodegradation of various polyorganosiloxanes (about 30 substances) under the influence of several biotype bacteria strain (16 types) were studied. A special procedure of biodegradation and analytical methods of evaluation the degree of degradation were applied. It was found that nearly all polysiloxanes test…
Abstract The crystal structure of α -Cu 3 SbS 3 at 493 K and 403 K was determined from single crystal data. The high-temperature modification, which is stable above 394 K, crystallizes in the orthorhombic system, space group Pnma (No. 62), a = 7.808(1) Å, b = 10.252(2) Å, c = 6.587(2) Å, and Z = 4 ( T = 493 K). From s…
Raman spectra of Ca 3 (VO 4 ) 2 calcium orthovanadate ( R 3 c space group), a high temperature ferroelectric with T c = 1383 K, are analyzed up to 1483 K with a group theory approach and discussed in relation to Raman spectra of other compounds with the palmierite structure ( R 3̄ m space group). The ferroelectric-par…
Abstract We prepared three different water‐soluble chitosan derivatives by the acylation of chitosan with corresponding acid anhydrides. The extent of acylation was determined by using the electric conductivity method. All of the chitosan derivatives were soluble enough to examine the respective mltioxidant activity i…
Abstract A series of symmetrical diols were synthesised through ring‐opening of lactones with different ring sizes by alkane diamines in moderate to good yields. Ring‐opening of the dilactones glycolide and lactide with a diamine in equimolar amounts afforded symmetrical diols in quantitative yield. Aliphatic poly(est…
Agglomerated crystals of norfloxacin were prepared by a spherical crystallization technique using the ammonia diffusion system (ADS). This technique makes it possible to agglomerate amphoteric drugs like norfloxacin, which cannot be agglomerated by conventional procedures. When an ammonia-water solution of norfloxacin…
Abstract L‐lactide was bulk‐polymerized in the presence of various commercially available iron compounds. The polymerization temperature was in the range of 140 and 230 °C, the monomer to initiator/catalyst ratio varied between 100 and 10 000, and the polymerization time between 30 minutes and 24 hours. Iron oxides, i…
Abstract The electronic conductivity of gadolinia doped ceria (Ce 0.8 Gd 0.2 O 1.8 ) was measured as a function of oxygen activity (a O z =1 corresponding to a gas with oxygen partial pressure p O 2 = 1.013 bar) in the range from a O z ≈︁10 1 to a O 2 ≈︁10 −13 for temperatures between 600 and 750°C. The Hebb‐Wagner po…
Abstract The fine clay (<0.1 μm) fraction of a clayey soil (Vertisol) from Sardinia (Italy) was studied by means of X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, cation exchange capacity (CEC) and surface area measurements. Smectites were the dominant clay minerals both in the parent mate…
Symmetry corrections are added to a structural optimization at constant pressure in order to preserve the symmetry during the numerical relaxation of a structure. The enthalpy is minimized as a function of the electronic structure, the metric ${g}_{\mathrm{ij}}$, and the atomic positions. For the antiperovskite struct…