Materials Literature
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All of the electron paramagnetic resonance (EPR) and optical data relating to some of the basic nickel-related defects in diamond have been compared, as well as previously little considered information about the effects of spin–orbit coupling and the magnitude of the crystal field. New models are proposed for the EPR…
The perfect 60° glide dislocation in diamond serves as an example of how different aspects of dislocations can be modelled in an approach combining continuum elasticity theory with atomistic density-functional-based tight-binding calculations. After investigating the perfect 60° dislocation and its isolated Shockley p…
A method for improving crystallographic phases is presented that is based on the preferential occurrence of certain local patterns of electron density in macromolecular electron-density maps. The method focuses on the relationship between the value of electron density at a point in the map and the pattern of density s…
For biomedical and electronic applications, it is highly desirable to deposit smooth diamond films with crystal sizes in the nanoscale range. We present experimental results of chemical vapour deposition diamond growth from CH 4 with incremental substitution of H 2 with He or Ar gases; the concentrations of the inert…
The effects of dispersed aerosil nanoparticles on two of the phase transitions of the thermotropic liquid-crystal material 4-n-pentylphenylthiol-4(')-n-octyloxybenzoate (8;S5) have been studied using high-resolution x-ray diffraction techniques. The aerosils hydrogen bond together to form a gel which imposes a weak qu…
Optically active and water-processable poly( N -alkylanilines) ( N -PAAs), such as poly( N -methylaniline), poly( N -ethylaniline), and poly( N - n -propylaniline), were synthesized by chemical polymerization of the corresponding monomer in the presence of dextran sulfate (DSA). The resultant N -PAAs were doped and in…
A method that uses both Hartree−Fock and hybrid Hartree−Fock density functional methods at the 6-311+G(2df,p) basis set level is used to calculate the 19 F NMR chemical shifts for possible Al−F species in sodium aluminosilicate glasses. The accuracy of this method has been carefully checked by calculating 19 F NMR shi…
Oxidative inactivation is a common problem for enzymatic reactions that proceed via iron oxo intermediates. In an investigation of the inactivation of a viral prolyl-4-hydroxylase (26 kD), electrospray mass spectrometry (MS) directly shows the degree of oxidation under varying experimental conditions, but indicates th…
The energies and thermodynamic parameters of the elementary reactions involved in the gas-phase hydrolysis of silicon tetrachloride were studied using ab initio quantum chemical methods (up to MP4//MP2/6-311G(2d,2p)), density functional (B3LYP/6-311++G(2d,2p)), and G2(MP2) theories. The proposed mechanism of hydrolysi…
Calmodulin (CaM) regulates a variety of cellular processes by interacting with a large number of proteins in a Ca(2+)-dependent manner. Conformational flexibility plays a key role in CaM function, although the full extent and detailed features of this flexibility are not fully characterized. Here, the 1.75 A resolutio…
Diamond coatings on Co cemented tungsten carbide (WC-Co) hard metal tools are widely used for cutting non-ferrous metals. It is difficult to deposit diamond onto cutting tools, which generally have a complex geometry, using a single step growth process. This paper focuses on the deposition of polycrystalline diamond f…
The Raman spectra of several surfactants such as didodecyldimethylammonium bromide (DDAB), cetyltrimethylammonium bromide (CTAB), dimyristoylphosphatidylcholine (DMPC), cetylpyridinium chloride (CPC), dihexadecyl phosphate (DHP), and sodium laurate (NaL) have been investigated in the solid, multilayer, micellar, and m…
Following recent experiments leading to the assignment of a trigonal vacancy–nitrogen–hydrogen complex in single-crystal chemical vapour deposited diamond, we have employed first-principles density functional supercell and cluster techniques to examine the structure and properties of such a defect. We find that the tr…
Photochromic diarylethenes, which bear carboxyl groups at the ortho, meta, or para positions of both terminal phenyl groups, have been synthesized. The diarylethenes adopt linear chain structures as a result of hydrogen bonding in the crystalline phase, and the crystals exhibit photochromic properties. The absorption…
We report an electrospray ionisation multistage mass spectrometry (ESI-MSn) method that utilises molecular mass information for determination of sequence distribution and chemical structure of mass-selected macromolecules of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) biopolyester, PHBH. On the basis of ESI-MSn stud…
The organic−inorganic (O−I) hybrid networks were prepared from two types of O−I precursors: (a) alkoxysilane-end-capped oligomers (ASO) and (b) epoxy-functional silsesquioxane (SSQO) clusters (EC). ASO precursors were cross-linked by hydrolysis and condensation of alkoxysilane groups and the EC by the reaction of the…
We study a class of growth processes in which clusters evolve via exchange of particles. We show that depending on the rate of exchange there are three possibilities: (I) Growth---clusters grow indefinitely, (II) gelation---all mass is transformed into an infinite gel in a finite time, and (III) instant gelation. In r…
The preparation of ordered and arranged Si quantum dots using a SiO/SiO 2 superlattice approach is presented. The different processes of phase separation and crystallization are studied in detail by infrared (IR) absorption and photoluminescence (PL) spectroscopy for different annealing temperatures from 300 to 1100 °…
The slow dynamics for a colloidal suspension of particles interacting with a hard-core repulsion complemented by a short-ranged attraction is discussed within the frame of mode-coupling theory for ideal glass transitions for parameter points near a higher-order glass-transition singularity. The solutions of the equati…
Using the first-principles pseudopotential method, we have studied simultaneous isovalent and n-type doping in diamond. We show that Si induces fully occupied isovalent levels near the valence band maximum. The Si levels interact with N donor levels, making them much shallower. The donor transition energy level of the…