Structure and properties of the crystalline-silicon-dioxide-based macroporous ceramics

Samples of macroporous ceramics based on crystalline silicon dioxide-(the pore diameter > 50 μm) with superficial membrane layers (the pore diameter 10–20 μm) are obtained. They meet the demands to porous materials for filtering. The samples based on the polydisperse powder of crystalline silicon dioxide with granulometric composition 100–315 μm, containing 11 wt % of silica-alumina binder, were formed under a pressure of 30 MPa; they demonstrated an optimal combination of porosity and mechanical strength. After thermal treatment the samples’ porosity came to ≈30%; the ultimate stress (compression) limit, to ≈35 MPa. It is shown that multilayer elements for filtering, with membrane layers formed of the silicon dioxide powder suspension, provide the water purification from iron impurity (from 1–2 mg/l and down to 0.3 mg/l, a sanitary standard). The elements for filtering with doubly deposited crystalline silica-based membrane layer (the particle size 10–50 μm) showed optimal combination of operation characteristics and the purity of water from iron. Original Russian Text ? A.I. Ratíko, A.I. Ivanets, T.A. Azarova, S.M. Azarov, 2008, published in Zashchita Metallov, 2008, Vol. 44, No. 2, pp. 217–222.     

Structural damage in ZnO bombarded by heavy ions

The effect of implantation parameters on damage build-up in ZnO bombarded with Bi and Er ions is studied by Rutherford backscattering/channelling spectrometry. The results show that the damage accumulation behaviour in ZnO is different dramatically from that in other semiconductors. In particular, a variation of implantation parameters, such as collision cascade density, sample temperature and ion flux, has only a minor influence on the damage accumulation in the crystal bulk for the case of such heavy ions. Moreover, an intermediate damage peak, between the surface and bulk defect peaks, is observed for all the irradiation conditions studied. The cascade density affects the behaviour of this intermediate peak with increasing ion dose.     

Electron-beam diagnosis of charged-particle beams with a rectangular cross section

Translated from Izmeritel'naya Tekhnika, No. 6, pp. 53–54, June, 1991.     

Monitoring the composition of the Cd<Subscript>1 − <Emphasis Type="Italic">z</Emphasis></Subscript>Zn<Subscript><Emphasis Type="Italic">z</Emphasis></Subscript>Te heteroepitaxial layers by spectroscopic ellipsometry

A hardware-software complex based on a spectroscopic ellipsometer integrated into a molecular beam epitaxy installation and destined to monitor the composition of the Cd_{1 − z} Zn _z Te alloy at small values of z is described. Methodical features of determination of the composition of growing layers by the spectra of ellipsometric parameters are considered. The procedure of determination of the composition by the absorption edge that allows measuring this parameter accurate to 1.2% is developed. Problems are considered the solutions of which will allow one to increase the resolution by the composition. In particular, maintaining a stable temperature during growth is required for this purpose.