Materials Literature
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The manganates La 0.80 Ca 0.20 MnO 3 , La 0.70 Ca 0.30 MnO 3 and La 0.70 Sr 0.30 MnO 3 exhibit the colossal magnetoresistive (CMR) effect. Total neutron diffraction was employed to yield information on both the average and local atomic structure of these disordered crystalline materials as a function of temperature. T…
We quantify the relationship between the atomic structures of the amorphous and the ordered and disordered crystalline phases of silica using neutron total scattering measurements to determine the local atomic configurations. The instantaneous local atomic arrangements of HP-tridymite and -cristobalite, both dynamical…
Grand canonical Monte Carlo molecular simulations have been carried out for adsorption of nitrogen at 77 K on square arrays of open and closed single-wall carbon nanotubes with diameters of 6−30 Å and nanotube separations of 4−30 Å. Exohedral spaces for arrays of closed nanotubes with small tube separations are microp…
The samarium(II) aryloxide complexes Sm(OAr) 2 (THF) 3 and [(C 5 Me 5 )Sm(μ-OAr)] 2 (Ar = C 6 H 2 t Bu 2 -2,6-Me-4) showed an extremely high activity for the ring-opening polymerization of ε-caprolactone (CL) and δ-valerolactone (VL). By using Sm(OAr) 2 (THF) 3 as an initiator, polyesters with very high molecular weig…
Six disaccharide amphiphiles were synthesized and their hydrogel-forming behavior was extensively studied. These amphiphiles were based on maltose and lactose. Since the gels formed from some of these systems showed the ability to “trap” water molecules upon gelation, these gels were described as “hydrogels”. When the…
The structural and magnetic properties of Mn5Ge3Cx films prepared at elevated substrate temperatures TS are investigated. In particular, films with x >= 0.5 and TS = 680 K exhibit a strongly enhanced Curie temperature TC = 440 K compared to Mn5Ge3 with TC = 304 K. Structural analysis of these films suggests that the c…
A method is presented for generating quasiregular arrays of nanometer-sized noble metal and metal oxide clusters on flat substrates by the use of a polymer template. The approach is of general applicability to other metals and various oxides. In the first step, polymeric micelles with a polar core were generated by di…
Results are presented of a detailed x-ray diffraction, Raman and thermal analysis study of the structural phase transitions in LiNH 4 SO 4 carried out in the temperature range 298-600 K. Either two or just one phase transition was recorded in the temperature range between 335 and 461 K, depending on the warming proces…
Low-temperature specific heat and magnetization measurements have been performed on the quantum spin system NH 4 CuCl 3 which has magnetization plateaus at one-quarter and three-quarters of the saturation magnetization. It is found that the present system undergoes three-dimensional magnetic ordering at T N = 1.3 K. I…
The magnetoelectric (ME) materials exhibit ferroelectric/ferrielectric/antiferroelectric properties in combination with ferromagnetic/ferrimagnetic/antiferromagnetic properties. Under the action of external magnetic field, such materials would show electric polarizations, while the external electric field would induce…
The yabJ gene in Bacillus subtilis is required for adenine-mediated repression of purine biosynthetic genes in vivo and codes for an acid-soluble, 14-kDa protein. The molecular mechanism of YabJ is unknown. YabJ is a member of a large, widely distributed family of proteins of unknown biochemical function. The 1.7-A cr…
The Ni atoms are deposited on the surface of the monodispersed Pd nanoparticles of 25 Å in size (magic number = 561) by reducing (CH3COO)2Ni·4H2O in 1-propanol under N2 at Ni/Pd molar ratios of 1/561 to 561/561 to obtain a series of Pd/Ni nanoparticles. The band structure of the Pd/Ni nanoparticles (Ni/Pd = 38/561) is…
High-resolution synchrotron X-ray and neutron powder diffraction techniques have been used to investigate the structural and magnetic phase transitions in two polycrystalline samples with nominal composition (Nd 0.5 Sr 0.5 )MnO 3 . The first sample separates into three coexisting macroscopic phases at low temperature:…
Cyclodextrins form inclusion complexes with iodine, which makes them candidates for iodine-sorption from nuclear waste gases. In model experiments it was shown that cyclodextrin-containing aqueous solutions and cross-linked cyclodextrin polymers were selective and effective iodine absorbers. Especially the α-cyclodext…
Properties of lead and its alloys processing of lead product application of lead lead in the environment.
Nanosized CdS clusters have been synthesized using polyester chains with a thiol end group as a covalently attached colloidal stabilizer. Clusters were grown through the reaction of thiourea with cadmium acetate, which was in competition with surface stabilization due to the tethered poly(caprolactone) (PCL) chains. T…
Simulations of the AC electrical characteristics of 2D square networks randomly filled with resistors or capacitors exhibit many features in common with experimental dielectric responses of solids. These include the `universal' fractional power law dispersions in permittivity and dielectric loss characterized by the C…
We present measurements of the transport spin polarization of Ni_xFe_{1-x} (0
While inert as bulk material, nanoscale gold particles dispersed on oxide supports exhibit a remarkable catalytic activity. Temperature-programmed reaction studies of the catalyzed combustion of CO on size-selected small monodispersed Au n ( n ≤ 20) gold clusters supported on magnesia, and first-principle simulations,…
In this paper we present and discuss the realization and optical characterization of porous silicon microcavities formed on p - -type doped substrates. We produce porous silicon microcavities with a very narrow bandwidth (5.5 nm) and a good ratio of the peak to background emission, reaching at the same time a high emi…