Materials Literature
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We have investigated the nonlinear surface impedance and two-tone intermodulation distortion of nine epitaxial YBa2Cu3O7-d films on MgO substrates, using stripline resonators, at frequencies f=2.3-11.2GHz and temperatures T=1.7K-Tc. The power dissipation decreased by up to one order of magnitude as the microwave elect…
Rod-, twinrod- and tetrapod-shaped CdS nanocrystals have been successfully prepared from the starting spherical CdS nanocrystals via a highly oriented solvothermal recrystallization technique. X-Ray powder diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy and high-resolution transmission…
The advent of structural genomics initiatives has led to a pressing need for high-throughput macromolecular structure determination. To accomplish this, new methods and inevitably new software must be developed to accelerate the process of structure solution. To minimize duplication of effort and to generate maintaina…
We study the pull-in voltage characteristics of several nanotube electromechanical switches, such as double-wall carbon nanotubes suspended over a graphitic ground electrode. We propose parametrized continuum models for three coupled energy domains: the elastostatic energy domain, the electrostatic energy domain and t…
Measured by ultra-slow scanning calorimetry and isothermal circular dichroism, human lung collagen monomers denature at 37 degrees C within a couple of days. Their unfolding rate decreases exponentially at lower temperature, but complete unfolding is observed even below 36 degrees C. Refolding of full-length, native c…
Recently, several studies have been carried out on sol–gel films for optical applications, mostly motivated by the quickness and low cost of the film preparation process. In order to preserve the coherence properties of the light, improvements in the current quality of such films are necessary as well as appropriated…
By direct imaging, we evaluate the relative stiffness of a hexagonal columnar mesophase induced by the self-organization of amphiphilic columnar supramolecules, both quantitatively and qualitatively, based on examination of the planar texture, and of defects contained therein. Quantitative measurement was performed by…
Abstract We synthesized some novel rigid NLO‐active maleimide copolymers bearing DR‐1 moieties ( PMPD , PHSD and PHND ). All copolymers exhibited high T g 's (190∼197 °C), good solubilities for common solvents and excellent film‐forming properties. Dependence of film thickness on the d 33 value for the poled copolymer…
An effective anchoring model for the patterned surface with bidirectional rubbing by atomic force microscope was proposed. The model was a simple additive function of two bidirectional anchoring contributions of the patterned surface, with consideration of higher-order terms of the anchoring function. The bistable swi…
GaN metal–oxide–semiconductor (MOS) capacitors were fabricated by using Ga oxide formed by photoelectrochemical oxidation of GaN. The electrical properties of the MOS structures as characterized by capacitance–voltage measurement were found to be dependent on the oxidation time and posttreatment. Positive flatband vol…
Vertically aligned carbon nanofibers (VACNFs) with vastly different spacing were grown by catalytically controlled dc glow discharge chemical vapor deposition. Both densely packed VACNFs and essentially isolated VACNFs were studied using scanning electron microscopy and x-ray energy dispersive spectroscopy. The morpho…
We have studied the local structure of GeSi nanocrystals embedded in SiO2 prepared by co-sputtering of Ge, Si, and SiO2 targets onto a Si(100) substrate. From Raman scattering, we conclude that the formation of the isotropic crystalline Ge phase starts at about 800 °C followed by the formation of a GeSi phase at highe…
1. We studied the distribution of epilithic diatoms in streams subjected to different degrees of human impact in order to evaluate their potential as bioindicators for environmental changes such as nutrient enrichment and acidification. 2. Three descriptors of the diatom assemblages were tested with respect to their p…
Novel higher-order mixed chelate complexes of lanthanide(III) have been synthesized, which contain 2,2′:6′,2-terpyridine (terpy, tridentate), 2,4-pentanedionate (acac, bidentate), and nitrate (NO3−, bidentate): general formula, [Ln(terpy)(acac)(NO3)2H2On]. Thirteen quaternary chelating complexes of the lanthanide seri…
The second-order susceptibilities in the ZnO films have been studied systemically. In very thin films, we observe an enhancement of second-order susceptibilities, which is larger than that of single-crystal ZnO. It was also observed that the second-order susceptibilities for ZnO films depend on the thickness but not o…
White-colored materials synthesized by a thermal annealing of milled GaN powders at 930 °C in a nitrogen atmosphere were identified to be monoclinic β-Ga2O3 nanowires by x-ray diffraction and scanning electron microscopy. High-resolution transmission electron microscopy revealed that these nanowires are single nanocry…
Electron-field-emission properties have been investigated systematically for carbon nanotubes (CNTs) fabricated on a metal tip. With a vacuum gap of 0.7 mm, the threshold field is as low as 0.7 V/μm and the current density approaches 10 mA/cm2 at an electronic field of 1.0 V/μm. The emission current is quite stable wi…
Carbon films whose hardness is comparable to diamond’s, but whose electrical conductivity is 19 orders of magnitude larger, have been discovered. The films were deposited onto silicon substrates by electron cyclotron resonance plasma sputtering. The bonding structure of the film was mainly sp2. The film consisted of s…
We report macroscopic synthesis of silica nanotubes by the sol–gel template method. A large number of silica nanotubes with small diameters (30–50 nm) were produced and were shaped into flakes successfully. Strong photoluminescence (PL) was observed in both as-grown and annealed nanotube flakes. The PL spectra have ma…
We have studied the magnetic-field-induced melting of the charge order in thin films of Pr0.5Ca0.5MnO3 (PCMO) films on SrTiO3 (STO) by X-ray diffraction, magnetization and transport measurement. At small thickness (25 nm) the films are under tensile strain and the low-temperature melting fields are of the order of 20…