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。
Siliceous mesostructured cellular foams (MCFs) with well-defined ultralarge mesopores and hydrothermally robust frameworks are described. The MCFs are templated by oil-in-water microemulsions and are characterized by small-angle X-ray scattering, nitrogen sorption, transmission electron microscopy, scanning electron m…
We present a model of the glass transition viewed as the agglomeration and growth of clusters forming a covalent network. The creation of new layers of atoms on the rims of the clusters is treated in a probabilistic way as a linear transformation (encoded in what is called a stochastic matrix ) of a vector whose compo…
The tris(phenyltin)-substituted tungstoantimonate(III) Cs6[(PhSn)3Na3(alpha-SbW9O33)2].20H2O (1) and the tetrakis-(phenyltin)-substituted tungstoarsenate(III) Na9[[(PhSn)2O]2H(alpha-AsW9O33)2].20H2O (2) have been prepared by reaction of phenyltin trichloride with Na9[alpha-SbW9O33].19.5H2O and Na9[alpha-AsW9O33].19.5H…
The crystal structure of Bacillus subtilis orotidine 5'-monophosphate (OMP) decarboxylase with bound uridine 5'-monophosphate has been determined by multiple wavelength anomalous diffraction phasing techniques and refined to an R-factor of 19.3% at 2.4 A resolution. OMP decarboxylase is a dimer of two identical subuni…
Pseudomonas sp. 61-3 (phbC::tet) strain, which is a phbCPs-disrupted mutant, accumulated a random copolymer consisting of (R)-3-hydroxybutyrate (3HB) and (R)-medium-chain-length 3-hydroxyalkanoate (3HA) units of 6-12 carbon atoms, but the 3HB fraction in the copolymer was less than 50 mol %, resulting in the formation…
The adsorption of pyridine, carbon dioxide (CO 2 ), and formic acid (HCOOH) on various types of surface sites of ZrO 2, vacant sites (for example: bare surface Zr 4+ O 2- ions), and those modified by terminal ( t -) and bridged ( b -) OH as well as t - and b -methoxy (OCH 3 ) groups, has been studied by infrared (IR)…
Orotidine 5'-phosphate decarboxylase produces the largest rate enhancement that has been reported for any enzyme. The crystal structure of the recombinant Saccharomyces cerevisiae enzyme has been determined in the absence and presence of the proposed transition state analog 6-hydroxyuridine 5'-phosphate, at a resoluti…
We prepared a stable and highly viscous suspension of cellulose microcrystals by postsulfating the HCl-hydrolyzed cellulose microcrystals. The neutralized suspension was isotropic and showed flow birefringence at low solid content (ca. <1%). At a solid content of approximately 2−3%, the suspension was still flowing bu…
Antiferromagnetic domains in an epitaxial thin film, LaFeO(3) on SrTiO(3)(100), were observed using a high-spatial-resolution photoelectron emission microscope with contrast generated by the large x-ray magnetic linear dichroism effect at the multiplet-split L edge of Fe. The antiferromagnetic domains are linked to 90…
Stoichiometric RMnO3 perovskites have been prepared in the widest range of R3+ ionic sizes, from PrMnO3 to ErMnO3. Soft-chemistry procedures have been employed; inert-atmosphere annealings were required to synthesize the materials with more basic R cations (R = Pr, Nd), in order to minimize the unwanted presence of Mn…
Thermoelectric (Peltier) heat pumps are capable of refrigerating solid or fluid objects, and unlike conventional vapor compressor systems, they can be miniaturized without loss of efficiency. More efficient thermoelectric materials need to be identified, especially for low-temperature applications in electronics and d…
We have resolved single-exponential relaxation dynamics of the 2-, 3-, and 4-electron-hole pair states in nearly monodisperse cadmium selenide quantum dots with radii ranging from 1 to 4 nanometers. Comparison of the discrete relaxation constants measured for different multiple-pair states indicates that the carrier d…
Ferromagnetism in manganese compound semiconductors not only opens prospects for tailoring magnetic and spin-related phenomena in semiconductors with a precision specific to III-V compounds but also addresses a question about the origin of the magnetic interactions that lead to a Curie temperature (T(C)) as high as 11…
The formation and crystal structure of a novel rare-earth compound series, R 3 Co 29 M 4 B 10 , have been investigated by electron microscopy, x-ray diffraction and Rietveld refinement. R 3 Co 29 M 4 B 10 can form for R = La, Ce, Pr, Nd, Sm, Gd, Ho, Tb, Er, Tm, Dy, Lu and M = Si, Al, Ge, and are isostructral with Nd 3…
The effects of range and geometry of a simple attractive square-well on the phase diagram of hard ellipsoids and hard spherocylinders is systematically studied using a simple van der Waals type theory. The orientational single particle distribution function is approximated using the Onsager trial function. The quantit…
This paper describes the growth of single crystals of Cr 4+ -doped Y 3 Ga 5 O 12 (YGG) and Y 3 Al 5 O 12 (YAG). Control of melt composition and post-growth annealing yields material that contains optimal concentrations of Cr 4+ ions in distorted tetrahedral sites normally occupied by Ga 3+ ions in YGG and Al 3+ ions i…
A tunnel junction based on the half-metallic oxide CrO 2 uses a native oxide barrier layer and a cobalt top electrode. The I : V characteristic is fitted to the Simmons model with = 0.76 eV and t = 2.0 nm. The magnetoresistance is positive with R / R = 1.0% at 77 K.
Samples with nominal compositions La 1.2 (Sr 1- x Ca x ) 1.8 Mn 2 O 7 ( x = 0.00, 0.25, 0.50, 0.65, 0.80 and 1.00) have been prepared and characterized by x-ray diffraction (XRD) and ac susceptibility techniques. Drastic changes in the XRD pattern and in the ac susceptibility versus temperature behaviour at x = 0.65 i…
Boron-doped diamond-like carbon (DLC) was prepared using an inductive radio-frequency Ar + C 2 H 2 + B 2 H 6 plasma-immersion ion-processing (PIIP) technique. The novel results show that B incorporation reduces the stress and that low-energy Ar-ion impingement suppresses the increase of the amount of hydrogen in the B…
Understanding the evolution of surface morphology or surface texture of molecular crystals by dissolution/etching may be useful in determining the dissolution mechanisms at the molecular level. In this study, partial dissolution tests were conducted on the (010) face of acetaminophen single crystals with selected solv…