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 general discussion of the designs and functions of the silk structures spiders use to capture prey has not been attempted since the book of Witt et al (319). Knowledge has increased so greatly in the intervening years that complete coverage is now impossible in a review article. I have cited primarily more recent an…
Anisotropic gels were produced by photopolymerization of an oriented liquid-crystalline (LC) mixture containing LC diacrylates and conventional LC molecules. Gels produced in this way were clear and did not give rise to excess scattering of light. Upon application of an electric field across the gel, the system turned…
Grain growth kinetics and grain‐boundary segregation of 12Ce‐TZP and 2Y‐TZP, containing divalent to pentavalent cationic dopants, were studied. In all cases, normal grain growth follwing the parabolic growth relation was observed at higher temperatures. The mobility of grain boundaries was suppressed by the addition o…
Transient cavitation is a discrete phenomenon that relies on the existence of stabilized nuclei, or pockets of gas within a host fluid, for its genesis. A convenient descriptor for assessing the likelihood of transient cavitation is the threshold pressure, or the minimum acoustic pressure necessary to initiate bubble…
Pseudomonas aeruginosa PAO and 15 other strains of this species synthesized a polyester with 3-hydroxydecanoate as the main constituent (55 to 76 mol%) if the cells were cultivated in the presence of gluconate and if the nitrogen source was exhausted; 3-hydroxyhexanoate, 3-hydroxyoctanoate, and 3-hydroxydodecanoate we…
We demonstrate control of the optical coupling between a pair of planar waveguides by application of voltage to surface-stabilized ferroelectric liquid-crystal films between them. A prototype switch exhibited a response time of 200 μs and a 40:1 switching ratio.
Conducting and transparent thin films of tin oxide were prepared by the laser evaporation of an undoped powder-pressed polycrystalline tin oxide target onto unheated substrates. After characterizing these films, the results reveal that the films are highly oriented and with a grain size ∼0.2 μm. The nearly stoichiomet…
We report the successful fabrication of ZnSe p-n junction light-emitting diodes in which Li and Cl are used as p-type and n-type dopants, respectively.
Photochromism has been studied for irradiated type Ib diamonds which are then annealed above 1500 degrees C. This mainly involves H2 and H3 centres. When the samples are illuminated with light of wavelength shorter than 600 nm, absorption of H2 centres is reduced while that of H3 centres is enhanced. In the dark the p…
Hyperfine fields and electronic structures were calculated by the KKR method to investigate the effects of the X atom on the magnetic properties of Co 2 MnX. The obtained magnetic moments of Co or Mn sites in Co 2 MnX are in good agreement with the experimental ones. Though the obtained hyperfine fields on Co or Mn si…
The magnetic structure of the weak ferromagnet ludlamite, Fe3(PO4)2.4H2O, has been re-examined by both polarized and unpolarized neutron diffraction from single crystal samples of the mineral. The crystal structure has been refined from three dimensional data collected at 20 K, the unit cell being monoclinic, a=10.542…
The structural phase transitions occurring in the chain compounds (CH 3 ) 4 NMnCl 3 (TMMC) and (CH 3 ) 4 NCdCl 3 (TMCC) are studied through X-ray diffraction measurements. In both compounds, the existence of a new high-temperature orientationally disordered phase is established (phase I') with space group P6 3 /mmc an…
The nonlinear conductivity in orthorhombic and monoclinic TaS 3 has been measured as a function of temperature from the Peierls transition temperature down to 4.2 K in the electric field range 10 -2 -500 V cm -1 . At liquid-helium temperature a sharp increase in conductivity is measured in a very limited variation ran…
X-ray diffraction has been used to study the interlayer structure of fluid freely suspended liquid-crystal films versus film thickness. The observed scattering is described extremely well by a simple interlayer density model based on predicted layer fluctuation ${\mathrm{\ensuremath{\sigma}}}_{\mathit{i}}$ and tilt an…
The free energy and the static elastic constants of a hard-sphere glass are calculated using density functional theory. More specifically, Bennett's glass model is used where the packing fraction of random closed packing, eta RCP , is taken as an adjustable parameter. As regards the density functional, the modified we…
Luminescence decay curves have been measured for the Eu 3+ emission and Tb 3+ emission in the cubic crystals Cs 2 NaTb 1-x Eu x Cl 6 at 80 and 293 K using pulsed dye laser excitation into the 5 D 4 state of Tb 3+ and the 5 D 1 state of Eu 3+ . For excitation of Tb 3+ , efficient energy transfer occurs to the 5 D 0 sta…
The scaling equations which determine the master functions for the beta -relaxation process within the mode coupling theory of supercooled liquids are reformulated such that a direct numerical solution becomes possible. Tables are presented that allow an accurate derivation of the scaling function and susceptibilities…
We report the observation of saturation with chain length of the second hyperpolarizability of a series of long, well-defined, conjugated oligothiophenes. This saturation occurs at the same length as that of the band gap and of the polarizability, and is attributed to a saturation of the effective conjugation length.…
We have observed anomalously enhanced self- (tracer) diffusion in systems of polymerlike breakable micelles. We argue that it provides the first experimental realization of a random walk for which the second moment of the jump-size distribution fails to exist (``Levy flight''). The basic mechanism is the following: Du…
Using the transient hot-wire method, thermal conductivity and heat capacity per unit volume are measured for solid and liquid phases and glassy crystal states of cyclooctanol, and information is provided on the phase diagram under high pressure. A new solid phase (III) is detected and characterized as a normal crystal…