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。
The doping of the chemical vapor deposition (CVD)-diamond $(100):\mathrm{H}(2\ifmmode\times\else\texttimes\fi{}1)$ surface with B and N has been studied using the density-functional tight-binding method. In agreement with recent experimental results, B doping is found to lower the abstraction energies and remove diffu…
We present a microscopic model to understand the magnetoelectric and second-harmonic spectra of ${\mathrm{Cr}}_{2}{\mathrm{O}}_{3}$ and the interference effect between the magnetic $({\ensuremath{\chi}}^{m})$ and electric $({\ensuremath{\chi}}^{e})$ second-order optical polarizations. The spin-orbit interaction and th…
We study the depletion interaction between spherical particles of radius R immersed in a dilute solution of rigid rods of length L . The computed interaction potential is, within numerical accuracy, exact for any value of L / R . In particular we find that for L ∼ R , the depth of the depletion well is smaller than th…
Highly branched poly(ε-caprolactones) with novel and well-defined molecular architectures have been synthesized by the use of new multifunctional initiators. The ring-opening polymerization methods used to prepare these new structures allowed accurate control of molecular weight and narrow molecular weight distributio…
Transparent oxyfluoride glass-ceramics can provide a low- phonon energy fluoride environment for active rare earth ions while maintaining the durability, formability, and mechanical strength of an oxide glass. Fluorescence from RE doped samples indicate substantial partitioning into the fluoride crystals. Eu<SUP>3+</S…
We have established time–temperature transformation and continuous-heating transformation diagrams for poly(ether–ether–ketone) (PEEK) and PEEK/poly(ether–imide) (PEI) blends, in order to analyze the effects of relaxation control on crystallization. Similar diagrams are widely used in the field of thermosetting resins…
The effects of electron-electron interaction on properties of zigzag carbon nanotubes with caps at both ends are theoretically investigated by employing an extended Peierls-Hubbard model. The electron-electron interaction is treated within the frame of Hartree-Fock approximation. Then the electronic structures and opt…
The process of order-to-disorder transition (ODT) has been studied in a symmetric diblock copolymer AB and in an asymmetric miktoarm star block copolymer of the AB3 type. We find that the TODT depends on the ordering temperature just as the melting temperature in semicrystalline homopolymers depends on the crystalliza…
The melting behavior of poly(ethylene terephthalate co-1,4-cyclohexylene dimethylene terephthalate) [PET/CT] random copolyesters has been studied. The basis of this analysis was the triple melting behavior of PET homopolymers, which is commonly observed after a period of isothermal crystallization followed by linear h…
A first-principles study of the frequency-dependent second-harmonic generation (SHG) coefficients of various SiC polytypes $(2H$, $4H$, $15R$, $6H$, and $3C)$, a group spanning the complete range of ``hexagonality,'' was carried out. It uses a recently developed computational approach based on the self-consistent line…
The gene fgd, which codes for F420-dependent glucose-6-phosphate dehydrogenase (FGD), was cloned from Mycobacterium smegmatis, and its sequence was determined and analyzed. A homolog of FGD which has a very high similarity to the M. smegmatis FGD-derived amino acid sequence was identified in Mycobacterium tuberculosis…
ABA-type block copolymers of poly(trimethylene carbonate) with poly(ethylene glycol) (Mn 6820), PTMC-b-PEG-b-PTMC, were synthesized by the ring-opening polymerization of 1,3-dioxan-2-one (trimethylene carbonate) in the presence of poly-(ethylene glycol) with stannous octoate catalyst, and the copolymers with various c…
Two chalcone-derivative isomers, 4,4′-diaminochalcone (4DAC) and 3,3′-diaminochalcone (3DAC), were synthesized and used as monomers together with tetracarboxylic dianhydrides to prepare novel photosensitive polyimides that contain a chalcone moiety in the main chain. The polyimides were characterized and their photoch…
SrRuO 3 epitaxial thin films were prepared by pulsed laser deposition (PLD) under a range of growth conditions to study the impact of bombardment on properties. Growth conditions favoring energetic bombardment resulted in SrRuO3 films with expanded in-plane and out-of-plane lattice constants. In particular, SrRuO3 fil…
The gene encoding the Escherichia coli Class I fructose-1, 6-bisphosphate aldolase (FBP aldolase) has been cloned and the protein overproduced in high amounts. This gene sequence has previously been identified as encoding an E. coli dehydrin in the GenBanktrade mark database [gene dhnA; entry code U73760; Close and Ch…
Small-size, high-density, and vertical-ordering Ge quantum dots are observed in strained Si/Ge short-period superlattices grown on Si(001) at low growth temperature by molecular-beam epitaxy. The photoluminescence (PL) peak position, the strong PL at room temperature, and the high exciton binding energy suggest an ind…
The hydrothermal reactions of molybdenum oxide starting materials with iron(II) and iron(III) halides in the presence of 2,2‘-bipyridine have afforded the three related one-dimensional solid materials [MoO 4 {Fe(III)Cl(2,2‘-bpy)}] ( 1 ), [Mo 3 O 12 {Fe(III)(2,2‘-bpy)} 2 ]·0.25H 2 O ( 2 ), and [Mo 4 O 15 {Fe(III)(2,2‘-…
Flux into the glycolytic pathway of most cells is controlled via allosteric regulation of the irreversible, committing step catalyzed by ATP-dependent phosphofructokinase (PFK) (ATP-PFK; EC 2.7.1.11), the key enzyme of glycolysis. In some organisms, the step is catalyzed by PPi-dependent PFK (PPi-PFK; EC 2.7.1.90), wh…
A new type of optical filter is predicted theoretically and verified experimentally. The filter operates under guided-mode resonance conditions in a thin-film waveguide grating. A high-efficiency reflection filter response is produced at the Brewster angle at which TM reflection is classically prohibited. Low-reflecta…
The efforts to reduce NOx pollutants have stimulated a large interest in the understanding of the elementary processes for NO transformation on transition metal surfaces. Periodic density-functional calculations have been performed for the molecular and dissociative chemisorption of NO on Pd and Rh(100) and (111) surf…