The Mechanism of Formation of Finely Dispersed Minerals on the Surface of Diamonds and the Application of Electrolysis Products of Water Systems for their Destruction

The composition of the surface of natural diamonds in interaction with kimberlite minerals and the aqueous phase in the depositand enriched ore is studied. The sequence and conditions for the formation of minerals on the surface of crystals under conditionsof processing of kimberlites have been determined. Confirmed the mechanism of hydrophilization of diamonds comprising crystallizationof hydroxides and oxides of iron as a mandatory initial stage. A method of destruction or subsequent dissolution of mineralsaggregates by the impact of electrolysis products of aqueous systems has been proposed, which allows to restore the hydrophobicityof diamonds. The use of electrochemically treated water in the froth separation cycle with high diamond recovery made it possibleto increase their recovery in the factory’s concentrate by 8.8%.

Peculiarities of quasicrystalline films formation processes on crystal surface under irradiation with proton-ion flows

Quasicrystalline film with densest package of atoms can be formed on a crystal surface under irradiating crystal surface with protonion flows at a certain ratio of atoms diameters of irradiated crystal and the ions of irradiating flow. Atom-free area of 1 Å order is formed. These are traps for protons from the irradiation stream, thus a quantum dot appears. Atomic package of quasicrystalline film is a package of equilateral Penrose rhombs and there are centers of atoms mass at the vertices. A mathematical relation is obtained that allows predicting radii of irradiation flux ions to form quasicrystalline film and select atomic composition of the obtained film with predetermined properties. Nanostructuring of materials is an entire family of physicochemical processes associated with proton transfer and their localization in crystal lattice and these include ion exchange, diffusion, and ion implantation. Ion and proton exchange can be considered an established universal method of surface modification technology [24– 26]. The case of implantation of protons into the structure of cluster systems formed on the surface of crystals is described in this paper. In this case, a quantum dot is formed in the cluster structure, which is a potential hole with quantized proton motion, wherein the radiation of quantum dot is in IR area of electromagnetic spectrum.

Calculation of the Stability and Reconstruction of the Crystal Surface within DFT-Calculations

The thin films’ surface is not perfect, so its properties and properties of the massive part of the film willdiffer significantly. Since a regularity in the formation of surface irregularities is observed, then the possibilitiesof computer modeling can be used to study such structures. To reproduce the surface of crystals with a NaClstructure, one can apply the same approaches in modeling properties as for metal oxides. The fundamentaldifference from the previous studies is in considering the structure in the direction (111), since such assumptionsallows to use a smaller simulation cell for computer calculations, which greatly speed them up. Approbation ofthe technique of repositioning the surface of lead sulfide thin films has been carried out.

Research on the Waterproof Properties of Lightweight Gypsum Materials

In this work, methods of introducing water-resistance to foamed gypsum were firstly adopted to investigate the influences of sulphoaluminate cement、redispersible latex powder and stearic acid emulsion on the mechanical strength、water absorption and softening coefficient. Scanning electron microscopy (SEM) was conducted to investigate microstructure of gypsum and phase composition of substances on plaster surface as well as the mechanisms. The result showed that sulphoaluminate cement reduced the water absorption of foamed gypsum, which decreases to 38.9% when dosage was 10%; Redispersible latex powder reduced the water absorption of foamed gypsum, which decreases to 35.6% when dosage was 5%; Stearic acid emulsion reduced the water absorption of foamed gypsum, which decreased to 30.1% when dosage was 3%; The combing use of sulphoaluminate cement、redispersible latex powder and stearic acid emulsion maked the water absorption decrease to 15.2% and the crystals became short and dense and a layer of organic hydrophobic membrane covered the surface of crystals and which makes gypsum less soluble and more suitable for use in humidity environment.

Synthesis and Structural Characterization of Zinc and Magnesium Doped Hydroxyapatite

Zn or Mg ions doped hydroxyapatite (HA) particles were successfully developed by introducing various concentration of Zn or Mg in the starting solution using wet chemical precipitation method and followed a hydrothermal treatment. The products were identified as HA by XRD and FTIR, and the precipitated particles had a rod-like morphology. All the products for Mg and Zn ions concentration in the preparation solution less than 40 mol% were identified as HA. Substitution of Mg and Zn in HA crystal would impair the crystallization of HA and significantly reduce the length of a, c values of HA unit cell, which clearly demonstrated that Mg or Zn ions were structurally incorporated into the apatite crystals, they were not just absorbed on the surface of crystals.

Rodlets associated with the cell wall and crystals of litter fungi

Crystals of calcium oxalate have been found associated with a series of basidiomycete hyphae. while the morphology of these crystals is quite variable, two forms have been commonly found in association with gymnospermous litter. Graustein et al. using SEM found star-shaped (druse-like) crystal conglomerates associated with Hysterangium crassum which they believed to be the result of oxalate secretion followed by precipitation on the surface of the hyphae. Another example of fungi forming druselike crystal aggregates on their hyphae was found in a basidiomycete wood rotting fungus in which the development of the crystals appeared to arise from within the hyphae. Examination of the material by SEM showed a sheath covering the surface of crystals supporting the internal origin of the oxalate crystals. In the present case litter fungi were collected in a mixed pine and fir forest 15 miles south of Nederland, Gilpin County, Colorado (Arnott no. 264). The fungi were fixed in the field in gluteraldehyde, treated with 3% glycerol and freeze fractured. Other specimens were stored dry or critical-point dried for study by SEM. The nature of the crystals was determined by chemical solubility, birefringence and x-ray analysis. The fungi are basidiomycetes.

Analysis of Domain-Size Distributions in Epitaxial Growth Using Leed Angular Profiles

Angular profiles of diffracted beams in surface-sensitive diffraction techniques can be used to establish the degree of order at the surface of crystals. Results are presented showing the sensitivity of such profiles to the growth mode of overlayer islands. A method is presented to incorporate the two-dimensional nature of the problem into the analysis and to extract finite-size effects from fundamental and superlattice beams.