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。
A series of novel, unsymmetrically substituted metallo-phthalocyanines was synthesized, along with their symmetrically substituted analogs, and the effects of structure and metal substitution on their photophysical and photoredox properties were investigated. The macrocycles were synthesized using a mixed-condensation…
The electrical resistivity of polymer composites is studied as a function of temperature. The initial resistivity ρ of thermoplastic or thermoset containing a metallic filler is in the range of 1–10×10−2 Ω cm. Around the curing temperature of epoxies, the resistivity increases by eight to twelve orders of magnitude. F…
The mechanical behavior of reaction‐sintered alumina: 30 vol% calcium hexaluminate (Al 2 O 3 :CaAl 12 O 19, or A1 2 O 3 : CA 6 ) composites was evaluated using the indentation strength in bending technique. A composite in which the hexaluminate (CA 6 ) phase possessed a platelike morphology showed more‐pronounced R ‐c…
A gene located at 443 kilobases on the Escherichia coli chromosome (subsequently designated ribE) was expressed in a recombinant E. coli strain and was shown to code for the enzyme 6, 7-dimethyl-8-ribityllumazine synthase. The recombinant enzyme was purified to homogeneity. The protein is an icosahedral capsid of 60 s…
The kinetics and mechanism of transpassive dissolution of thin, sputter‐deposited Cr 2 O 3 films and passivated Cr were studied with in situ x‐ray near‐edge spectroscopy in 1 M H 2 SO 4 , borate buffer (pH 8.4), and 1 M NaOH. The onset potentials of the transpassive dissolution and the plateau potentials during galvan…
An isotropic high‐density graphite was used as a polarizable electrode of all‐solid state electric double‐layer capacitor using polyethylene oxide (PEO) or gel PEO electrolyte. The all‐solid‐state capacitor with high‐density graphite electrodes possesses higher differential capacity than the other flat electrodes in s…
Phonon modes of CdSe quantum dots in various glass matrices are investigated by Raman spectroscopy. The phonon energies are observed to be dependent on the host matrix as well as the quantum dot size. We have shown that the lattice contraction effect must be introduced to explain the observed differences of the phonon…
The microscale syntheses of Tetraphenylporphyrin, H 2 (TPP), and the corresponding metalloporphyrins Zn II (TPP) and Ni II (TPP) are reported. H 2 (TPP) is synthesized by the condensation of benzaldehyde and pyrrole, and the subsequent metallation of H 2 (TPP) is achieved with anhydrous Zn II Cl 2 or Ni II Cl 2 in DMF…
Using a pin‐on‐plate tribometer with the reciprocating motion of SiC against yttria‐doped tetragonal zirconia polycrystal (Y‐TZP) plates, the friction and wear of Y‐TZP ceramics were investigated as a function of grain size in dry N 2 at room temperature. The results showed that the overall wear resistance increased a…
It has been shown that the temperature behavior of dielectric permittivity ($\ensuremath{\varepsilon}$) in the isotropic phase of nematogens can be described in the same way as in critical binary solutions. Hence, using a relation with the critical exponent $\ensuremath{\varphi}=1\ensuremath{-}\ensuremath{\alpha}=0.5\…
Synergistic effects between erosion and corrosion processes on mild steel (MS) in an aqueous carbonate-bicarbonate solution were studied using electrochemical measurements from a rotating cylinder electrode (RCE) system. A rigorous basis for definition and measurement of the “pure” erosion rate and corrosion rate was…
RATIONALE AND OBJECTIVES: The authors compare in vivo transmetallation of three magnetic resonance contrast agents in humans in terms of their kinetic stability. METHODS: Blood and urine samples were taken before and after the intravenous injection of gadolinium (Gd)-HP-DO3A, Gd-DTPA, or Gd-DTPA-BMA at 0.1 mmol/kg to…
A new assessment of the thermodynamic properties of the stable phases of the Ni-Ti system is presented, based on the experimental thermochemical and phase diagram data from the literature. Suitable sublattice models are used to describe the non-stoichiometries of NiTi and Ni 3 Ti. The calculated phase diagram and the…
Using electron paramagnetic resonance two types of ${\mathrm{Ti}}^{3+}$-related centers are identified in BaTi${\mathrm{O}}_{3}$, which are attributed to ${\mathrm{Ti}}^{3+}$-${V}_{\mathrm{O}}$ and to ${\mathrm{Ti}}^{3+}$-${V}_{\mathrm{O}}$ associated with Na or K, respectively. This assignment is based on the chemica…
Abstract Calculations of electron inelastic mean free paths and stopping powers for several alkali halides (KF, KCl, KBr, and KI) and metal oxides (BeO, MgO, SiO 2 , and Al 2 O 3 ) have been performed in the 50 eV to 10 keV energy range. The complex dielectric formalism, improved to include the energy gap, was used fo…
In enteric bacteria, the hexitol galactitol (Gat) (formerly dulcitol) is taken up through enzyme II (II(Gat)) of the phosphoenolpyruvate-dependent phosphotransferase system (PTS), and accumulated as galactitol 1-phosphate (Gat1P). The gat genes involved in galactitol metabolism have been isolated from the wild-type is…
Abstract A well-characterized kaolinite has been hydrated in order to test the hypothesis that platey kaolinite will roll upon hydration. Kaolinite hydrates are prepared by repeated intercalation of kaolinite with potassium acetate and subsequent washing with water. On hydration, kaolinite plates roll along the major…
We have investigated the activation barriers and the intermediate paths of the transformation to cubic diamond and that to hexagonal diamond from graphite under pressure, allowing both atomic geometry and unit-cell shape to vary, in order to clarify the difference of the microscopic mechanisms between them. For this i…
Cuboid silsesquioxanes with appropriate side chains (see below; n = 4, 6, 11) provide a means of structuring soft matter with inorganic cores. These compounds combine material characteristics of polymer and low molecular mass liquid crystals.
The purpose of this work was to evaluate the effect of compositional modifications on the electrical properties of lead lanthanum zirconate stannate titanate (PLZST) ceramics, as well as to examine their electrically induced phasechange behavior. Variations in the Ti:Sn ratio were evaluated. Increased Ti 4+ content pr…