Materials Literature
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The preparation of biocolloids with organized enzyme-containing multilayer shells for exploitation as colloidal enzymatic nanoreactors is described. Urease multilayers were assembled onto submicrometer-sized polystyrene spheres by the sequential adsorption of urease and polyelectrolyte, in a predetermined order, utili…
We present large scale simulations of the diffusion constant $D$ of a random composite consisting of aligned platelets with aspect ratio $a/b>>1$ in a matrix (with diffusion constant $D_0$) and find that $D/D_0 = 1/(1+ c_1 x + c_2 x^2)$, where $x= a v_f/b$ and $v_f$ is the platelet volume fraction. We demonstrate that…
Dislocation core properties of Al with and without H impurities are studied using the Peierls-Nabarro model with parameters determined by ab initio calculations. We find that H not only facilitates dislocation emission from the crack tip but also enhances dislocation mobility dramatically, leading to macroscopically s…
We have used tight-binding molecular-dynamics simulations to investigate the role of point defects (vacancies and interstitials) on structural relaxation in amorphous silicon. Our calculations give unambiguous evidence that point defects can be defined in the amorphous solid, showing up as anomalies in the valence-cha…
Two different hot isostatic pressing cycles (HIPing) were investigated to synthesize bulk MgB2 samples: a "standard" cycle where a low vessel pressure is maintained while heating to the process temperature with a subsequent simultaneous pressure and temperature decrease and a new method - dense material cooling under…
Via batch process in an autoclave, we conducted foam processing on polypropylene (PP)/clay nanocomposite (PPCN) by using supercritical CO 2 as foaming agent under 10 MPa at 134.7 °C. Through transmission electron microscopy observation, the biaxial flow-induced alignment of clay particles along the cell boundary was i…
We present a mechanism for the compensation of N acceptors in ZnO through real-space multigrid electronic structure calculations within the local-density-functional approximation. We find that at low N doping levels using a normal ${\mathrm{N}}_{2}$ source, O vacancies are the main compensating donors for N acceptors,…
The presence of space charge in the polymeric insulation of high-voltage cables is thought to be correlated with electric breakdown. However, a direct link between molecular properties, space charge formation and eventual breakdown has still to be established. It is clear that both physical (e.g., conformational disor…
The structural properties, the static and relaxation dielectric coefficients $[{\ensuremath{\epsilon}}_{j}$ and ${\ensuremath{\epsilon}}_{j}(\ensuremath{\omega})$ $(j=\ensuremath{\Vert},\ensuremath{\perp})],$ the rotational diffusion constants ${D}_{\ensuremath{\perp}}$ and ${D}_{\ensuremath{\Vert}},$ the orientationa…
Electric-field-induced structural transition of a single crystal $\mathrm{Pb}({\mathrm{Zn}}_{1/3}{\mathrm{Nb}}_{2/3}){\mathrm{O}}_{3}\ensuremath{-}8%{\mathrm{PbTiO}}_{3}$ grown in the (001) direction was studied by use of Raman scattering spectroscopy. By comparing the changes in Raman spectra induced by the electric…
We demonstrate that elastic properties of cluster-assembled carbon films can be measured by surface Brillouin scattering. We have studied films with different nano- and mesostructures produced with different precursor cluster mass distributions. In particular, films showing very high and low surface roughness have bee…
The salts [18-crown-6-K](4)[Sn(4)Se(10)].5en and [18-crown-6-K](4)[Sn(4)Te(10)].3en.2THF were isolated upon addition of THF to the ethylenediamine (en) extracts of the alloys KSn(0.90)Se(1.93) and K(4)Sn(4)Te(10) that had been extracted in the presence of 18-crown-6 (1,4,7,10,13,16-hexaoxacyclooctadecane). The Sn(4)Te…
Dynamics of the spin system has been investigated in a ferromagnetic ${\mathrm{La}}_{0.7}{\mathrm{Ca}}_{0.3}{\mathrm{MnO}}_{3}$ film by means of a time-resolved pump-probe method. In a weak excitation condition, the relaxation time $\ensuremath{\tau}$ increases critically on approaching the critical temperature ${T}_{…
Positive magnetoresistance (MR) in ${\mathrm{La}}_{0.7}{\mathrm{Pb}}_{0.3}{\mathrm{MnO}}_{3}$ single crystals was observed between temperatures 4.2 and 50 K, in addition to the negative colossal magnetoresistance (CMR) at higher temperatures. The positive MR increases with temperature lowered and reaches $20%$ at $T=4…
Thickness inhomogeneities in thin films have a large influence on their optical transmission and reflection spectra. If not taken into account, this may lead to rather large calculated values for the absorption coefficient or the erroneous presence of an absorption-band tail, as well as to significant errors in the ca…
Incorporation and lattice migration of cesium in three apatites fluorapatite ${\mathrm{Ca}}_{10}({\mathrm{PO}}_{4}{)}_{6}{\mathrm{F}}_{2},$ lanthanum-fluorobritholite ${\mathrm{Ca}}_{4}{\mathrm{La}}_{6}({\mathrm{SiO}}_{4}{)}_{6}{\mathrm{F}}_{2}$ and lanthanum-oxyapatite ${\mathrm{Ca}}_{2}{\mathrm{La}}_{8}({\mathrm{SiO…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTPhosphorous Acid and Arsenious Acid as LigandsMaxim N. Sokolov, Alexander V. Virovets, Danil N. Dybtsev, Elena V. Chubarova, Vladimir P. Fedin, and Dieter FenskeView Author Information Institute of Inorganic Chemistry of the Russian Academy of Sciences, pr. Lavrentjeva…
We consider the electronic properties of layered molecular crystals of the type $\ensuremath{\theta}\ensuremath{-}{D}_{2}A$ where A is an anion and D is a donor molecule such as bis-(ethylenedithia-tetrathiafulvalene) (BEDT-TTF), which is arranged in the $\ensuremath{\theta}$-type pattern within the layers. We argue t…
The efficient reversible functionalization of the periphery of urea adamantyl poly(propylene imine) dendrimers with catalytic sites using noncovalent interactions is described. Phosphine ligands equipped with urea acetic groups, a binding motive complementary to that of the dendrimer host, have been prepared and assem…
The geometry of the multiple diffraction of a (001) silicon wafer in an x-ray powder diffractometer is elucidated. In particular, multiple diffraction occurs only when the sample is rotated (along the sample normal) to one of the specific azimuthal angles. A derivation based on analytical geometry is performed to obta…