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。
We demonstrate electrical electron spin injection via interband tunneling in ferromagnetic/nonmagnetic semiconductor Esaki diodes. An interband tunnel junction between ferromagnetic p+-(Ga,Mn)As and nonmagnetic n+-GaAs under reverse-bias allows spin-polarized tunneling of electrons from the valence band of (Ga,Mn)As t…
Seit den ersten Berichten über Übergangsmetallkomplexe mit Pinzetten-Liganden in den späten siebziger Jahren haben diese Systeme wegen der ungewöhnlichen Eigenschaften, die das Metallzentrum durch den Pinzetten-Liganden erhält, zunehmendes Interesse hervorgerufen. Typischerweise enthält ein solcher Ligand einen anioni…
Ferroelectric properties along the a(b) axis and c axis in single crystals of various bismuth layer-structured ferroelectrics (BLSFs) were investigated. By measuring saturated P-E hysteresis curves of BLSFs, values of the saturated remanent polarization and the coercive electric field were found to be related to the C…
Some methyl 4,6-O-benzylidene monosaccharides can act as strong low molecular weight gelators for various organic solvents. As they are accessible in a variety of homologues, each with a unique molecular architecture, they can be used for systematic studies of gelation phenomena. Structural details of their hydrogen-b…
Detailed studies of the temperature (5--350 K) and magnetic field variations (up to $H=50\mathrm{kOe})$ of the magnetization of CuO nanoparticles of nominal size range 37--6.6 nm are reported. These particles were synthesized by the sol-gel method in combination with high-temperature annealing, followed by structural…
Acetogenic bacteria contain acetyl-CoA synthase (ACS), an enzyme with two distinct nickel-iron-sulfur active sites connected by a tunnel through which CO migrates. One site reduces CO2 to CO, while the other synthesizes acetyl-CoA from CO, CoA, and the methyl group of another protein (CH3-CP). Rapid binding of CO2 and…
An ethylene−hexene copolymer, representative of many heterogeneous linear low-density polyethylenes (LLDPEs), has been shown to contain a dispersed minority phase (volume fraction ∼10 -2 ), which was manifested by departures from a Q -2 variation of the neutron scattering cross section at low Q values. After xylene ex…
The synthesis of DOTA tris(phenylmethyl) ester 2, a new monoreactive derivative of DOTA, is described. This versatile synthon can be easily coupled to compounds bearing an amino group and then deprotected to DOTA monoamide under mild and neutral conditions by catalytic hydrogenolysis. Accordingly, compound 2 has been…
Thin films containing nanometer-sized PrAlO 3 or NdAlO 3 crystals evenly dispersed in an amorphous Al 2 O 3 matrix were grown by chemical vapor deposition (CVD) of heterometal alkoxides, [Ln{Al(O Pr i ) 4 } 3 ( Pr i OH)] (Ln = Pr ( 1 ), Nd ( 2 )). The lanthanoid to aluminum ratio in the precursors, established by sing…
Silanization of glass surfaces by (3-glycidoxypropyl)trimethoxysilane (GPS) provided a surface-coupled layer of functional molecules for the subsequent reaction with aniline (An). The so-modified glass surface (the An−GPS−glass surface) was then subjected to oxidative graft polymerization of aniline. The composition a…
We describe the first structure determination of a type II citrate synthase, an enzyme uniquely found in Gram-negative bacteria. Such enzymes are hexameric and are strongly and specifically inhibited by NADH through an allosteric mechanism. This is in contrast to the widespread dimeric type I citrate synthases found i…
The thermoresponsive and pH-responsive intelligent copolymers of N -vinylformamide (NVF) and N -vinylisobutyramide (NVIBA), and their derivatives with primary amino groups, were synthesized. Hydrolysis of poly(NVF), poly(NVIBA), and poly(NVF- co -NVIBA) to obtain poly(vinylamine) [poly(VAm)] was carried out under acid…
Photoreactive decatungstates Na 4 W 10 O 32 and (nBu 4 N) 4 W 10 O 32 were heterogenized inside the silica network via a sol−gel technique, resulting in the Na 4 W 10 O 32 /SiO 2 (Na 1 ) and (nBu 4 N) 4 W 10 O 32 /SiO 2 (Q 1 ) composites. The physicochemical properties of as-synthesized composites were measured by UV…
Polyaniline base and polyaniline hydrobromide were reacted with bromine in aqueous medium. The content of bromine in the modified polymer increased with the amount of bromine introduced into the reaction mixture. The enhanced conductivity of polyaniline base after reaction with bromine was explained by the protonation…
The incorporation of cyclodextrin (CD) groups inside mesoporous silica frameworks was attempted using two methods: by the grafting of the CD groups into the channels of preformed mesoporous silica hosts and by the direct synthesis of CD-containing mesoporous materials by a one-step process. While the grafting procedur…
Due to phase separation in the silicate melt, the synthesis of fluorosmectites ([Na 0.5 ] inter [Mg 2.5 Li 0.5 ] oct [Si 4 ] tet O 10 F 2 ) from the melt without mechanical mixing yields an inhomogeneous material. Because of the solid solution capability of the 2:1 layer silicate structure, the nonuniformity in chemic…
Hard-particle packings have served as useful starting points to study the structure of diverse systems such as liquids, living cells, granular media, glasses, and amorphous solids. Howard Reiss has played a major role in helping to illuminate our understanding of hard-particle systems, which still offer scientists man…
[reaction--see text] For the gold-catalyzed phenol synthesis an intramolecular migration of the oxygen atom was proven. Several other late transition metals with d(8) configuration allow this conversion, providing evidence for Au(III) being a catalytically active species. On the other hand gold was still the most acti…
The two title trialkaline trioxoantimonates(III), tripotassium trioxoantimonate(III), K(3)[SbO(3)], (I), and tricaesium trioxoantimonate(III), Cs(3)[SbO(3)], (II), crystallize in the cubic Na(3)[AsS(3)] structure type in space group P2(1)3. The structures show discrete Psi-tetrahedral [SbO(3)](3-) anions with C(3v) po…
In the glass industry, the lifetime of many metallic parts in contact with molten glass is controlled mainly by high temperature corrosion which, as for aqueous solutions is governed by oxidation-reduction reactions: reduction of glass components counterbalances the oxidation of metallic components. Depending on the g…