Materials Literature
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Cavities or packing defects in proteins may generally be related with the dynamics and function of a protein. In the c-Myb R2 subdomain, its single cavity has been shown to be crucial for its DNA recognition. Cavities are also considered important in determining the pressure stability of a protein. In the present work…
In order to facilitate the large-scale preparation of active class II polyhydroxyalkanoate (PHA) synthase, we constructed a vector pT7-7 derivative that contains a modified phaC1 gene encoding a PHA synthase from Pseudomonas aeruginosa possessing six N-terminally fused histidine residues. Overexpression of this phaC1…
The orbital free ab initio molecular dynamics method is applied to study the static and dynamic structure of liquid Al near the triple point. The method uses a new kinetic energy functional, along with a local pseudopotential constructed within the same kinetic energy functional. The results obtained for the dynamic s…
Resonant behavior of the Raman process is predicted when the laser frequency is close to the orbital excitation energy of ${\mathrm{LaMnO}}_{3}$ at 2 eV. The incident photon creates a vibrationally excited self-trapped ``orbiton'' state from the orbitally ordered Jahn-Teller (JT) ground state. Trapping occurs by local…
Using first-principles total energy calculations, we found that the doping of Li into (6,0) nanotubes has no insertion barrier if the tube mouth is passivated. The diffusion barrier is extremely small inside the nanotube, and Li atoms prefer to reside along the tube axis. The reaction is strongly exothermic. The Li-Li…
We explored the effect of the ratio of bond length to excluded volume bead diameter, l0/d0, of simple bead–spring homopolymer chains on the resulting liquid structure of dense, monodisperse polymer melts. We conducted NVT molecular dynamics simulations of both bulk and planar confined polymer liquids. We find that bot…
The geometries, formation energies, and diffusion barriers of carbon point defects in silica (\ensuremath{\alpha}-quartz) have been calculated using a charge-self-consistent density-functional based nonorthogonal tight-binding method. It is found that bonded interstitial carbon configurations have significantly lower…
${\mathrm{NdNiO}}_{3}$ is studied by electron diffraction and by Raman scattering, and drastic changes are observed at the metal-insulator transition. These features are explained in the framework of a charge disproportionation of nickel, which is at variance from earlier results, but consistent with recent studies on…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTPreparing Carbon Nanotubes and Nested Fullerenes from Supercritical CO2 by a Chemical ReactionMenachem Motiei, Yaron Rosenfeld Hacohen, Jose Calderon-Moreno, and Aharon GedankenView Author Information Department of Chemistry, Bar-Ilan University Ramat-Gan, Israel 52900…
Direct evidence for a size effect in self-trapped exciton (STE) photoluminescence (PL) from silica-based nanoscale materials as compared with bulk type-III fused silica is obtained. Two kinds of mesostructures were tested: (1) silica nanoparticle composites with primary particle size of 7 and 15 nm, (2) ordered and di…
The wetting behavior of homopolymer on a chemically identical polymer brush is mathematically equivalent to the interaction between a pair of opposing brushes in a matrix of parent homopolymer. We examine both systems using self-consistent field theory (SCFT) with a new highly efficient and accurate algorithm. Our cal…
Two- and three-dimensional superlattices formed from a family of amine-stabilized gold nanoparticles were investigated by transmission electron microscopy and selected area diffraction studies. The samples were prepared by ligand-exchange reactions between a phosphine-stabilized 1.5 nm precursor and pentadecylamine an…
The mechanism of aerobic oxidation of aromatic and alkyl aromatic compounds using anthracene and xanthene, respectively, as a model compound was investigated using a phosphovanadomolybdate polyoxometalate, H(5)PV(2)Mo(10)O(40), as catalyst under mild, liquid-phase conditions. The polyoxometalate is a soluble analogue…
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,…