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。
RATIONALE AND OBJECTIVES: Monochromatic quantitative computed tomography allows a nondestructive and quantitative measurement of gadolinium (Gd) concentration. This technique was used in the C6 rat glioma model to compare gadopentetate dimeglumine and gadobutrol. METHODS: Rats bearing late-stage gliomas received 2.5 m…
A “simple” catalyst of TaBr 5, NbBr 5, or NbBr 3 ·CH 3 O(CH 2 ) 2 OCH 3 is developed, which readily effects polycyclotrimerizations of α,ω-alkenediynes {HC⋮C(CH 2 ) m C⋮CH, m = 4−6 [ 1 ( m )]} at room temperature, giving hyperbranched poly(alkenephenylene)s [ hb -P 1 ( m )] with high molecular weights ( M w up to ∼270…
Commercially pure nickel-titanium powders were mechanically milled in a vertical attritor mill under protective atmosphere for various times from 10 to 24 hr. Products were then compacted and sintered at different temperatures for different times. Amorphization and interatomic phase formation were determined by X-ray…
Picolyl hydrazide ligands have two potentially bridging functional groups (micro-O, micro-N-N) and consequently can exist in different coordination conformers, both of which form spin-coupled polynuclear coordination complexes, with quite different magnetic properties. The complex [Cu(2)(POAP-H)Br(3)(H(2)O)] (1) invol…
The dynamics of ultrasound-induced cavitation bubbles situated in non-Newtonian liquids and near a rigid boundary are investigated experimentally by acoustic measurements and high-speed photography with up to 4 million frames/s. The non-Newtonian liquids consist of a 0.5% polyacrylamide (PAM) aqueous solution with a s…
Single-walled carbon nanotubes (SWNTs) were coated with silica by treating a mixture of a basic sodium silicate solution and a surfactant-stabilized suspension of SWNTs with EtOH. The SiO2−SWNTs were cast on solid substrates to form woven mats comprising a variety of unique nanostructures including loops, curls, inter…
An investigation of the ultrafast excited state dynamics of triporphyrin and hexaporphyrin arrays consisting of covalently linked Zn tetraphenylporphine (ZnTPP) and free base tetraphenylporphine (FbTPP) units is reported. The interchromophoric distance in the hexamers is of the order of 13 Å, while it varies from 26 t…
Abstract Potential and limits of dynamic mechanical analysis (DMA) as a tool for fracture resistance evaluation of isotactic polypropylenes and their polyolefin blends are presented. A minimum of information about the materials under investigation is a prerequisite to interpret the DMA traces in a right way. Although…
Formation and aggregation of photolytic gold nanoparticles at the surface of chitosan (CTO) films have been investigated. When thin films of chloroauric acid salt of CTO were irradiated with UV light in wet air at room temperature for 10 min, gold nanoparticles of approximately 10 nm size are formed at the film surfac…
Abstract A series of new polyimides was prepared by reacting 2,6‐diaminopyridine with various aromatic dianhydrides in DMF in 1 : 1 mole ratio. All the resulting polyimides were readily soluble in organic solvents such as dimethylformamide, N,N ‐dimethylacetamide, pyridine, m ‐cresol, THF, etc. They also show good fil…
Through layer-by-layer (LBL) assembly technique, iron oxide (Fe 3 O 4 ) nanoparticles coated by poly (diallyldimethylammonium chloride) (PDDA) and Preyssler-type polyoxometalates (NH 4 ) 14 NaP 5 W 30 O 110 ·31H 2 O (P 5 W 30 ) were alternately deposited on quartz and ITO substrates, and 4-aminobenzoic acid modified g…
A versatile crystal-growth simulation program, based on the Monte Carlo algorithm, is introduced. It enables the handling of any crystallographic orientation. The crystal is modeled by a set of molecular interactions, which are obtained from molecular mechanics calculations. The motherphase is parametrized by its bulk…
A series of trinuclear Cu(II)Ln(III)Cu(II) complexes with the bridging ligand 2,6-di(acetoacetyl)pyridine have been prepared by one-pot reaction with Cu(NO(3))(2).3H(2)O and Ln(NO(3))(3).nH(2)O in methanol. X-ray crystallographic studies for all the complexes indicate that two L(2)(-) ligands selectively sandwich two…
Reactivity, kinetic, and thermodynamic studies are reported for reactions of a rhodium(II) bimetalloradical with H(2), and with the methyl C-H bonds for a series of substrates CH(3)R (R = H, CH(3), OH, C(6)H(5)) using a m-xylyl diether tethered diporphyrin ligand. Bimolecular substrate reactions involving the intramol…
Abstract Polymer melt‐direct intercalation or exfoliation is a promising approach for the preparation of nanocomposites. The structure of nanoclay platelets in the nanocomposites depends not only on the properties of polymer matrix and nanoclay, but also on the operating conditions during processing. The objective of…
Polyelectrolyte multilayers with continuously variable amounts of ionizable weak acid functionality were prepared by blending ionizable and nonionizable polyelectrolytes in the deposition solutions. Diluting ionizable groups in this way yielded multilayers that were more structurally stable, shown by thickness and ato…
Calcium carbonate is an important and ubiquitous component of biological and geochemical systems. In this study, the surface chemistry of calcium carbonate with several trace atmospheric gases including HNO3, SO2, HCOOH, and CH3COOH is investigated with infrared spectroscopy. Adsorbed carbonic acid, H2CO3, is found to…
Here we review major breakthroughs in the rapidly developing research area of nanomaterial synthesis in supercritical fluids focusing on both the fundamental science and processing advantages in the application areas of separations, assembly and scale-up of synthesis. Density-tunable control of the solvation strength,…
We have utilized resonant x-ray diffraction at the Mn L(II,III) edges in order to directly compare magnetic and orbital correlations in Pr0.6Ca0.4MnO3. Comparing the widths of the magnetic and orbital diffraction peaks, we find that the magnetic correlation length exceeds that of the orbital order by nearly a factor o…
The pH-dependent loading and release behavior of small hydrophilic molecular probes in polyallylamine and hyaluronic acid multilayer films was investigated. These studies were carried out using the water-soluble dyes Indoine Blue and Chromotrope 2R, and their loading and release profiles were followed with UV−vis spec…