Contact stability of C60 molecules on pure and doped (100) tungsten surface

The influence of the metal surface doping on the contact stability of adsorbed fullerene molecules at room temperature was observed for the first time. The C₆₀ fullerene molecules decompose at room temperature both on a pure (100)W surface and on a tungsten surface containing carbide (WC), while the presence of a surface silicide of the same stoichiometry (WSi) produces passivation of the metal surface, thus preventing the fullerene molecules from decomposition.     

Flux growth of single magnetic sublattice antiferromagnetic garnets Ca3 Fe2 Ge3 O12 and Ca3 Mn2 Ge3 O12

Magnetic single crystals garnets Ca₃ X₂ Ge₃ O₁₂ with X = Mn³⁺ or Fe³⁺ containing Ca²⁺ and Ge⁴⁺ are of great interest due to the rise of an antifer-romagnetic order in one definite octahedral site. The optimal conditions for obtaining single magnetic-sublattice garnets of large size (1 cm in diameter) have been analyzed. Two groups of solvents have been tested: Bi₂ O₃ or PbO based flux. The best results were obtained with PbO flux and starting composition : % Moles 44 PbO 1b 35 GeO₂ 1b 15 CaO 1b 6 X₂ O₃.     

Coadsorption of Oxygen and C60 Molecules on (100)Mo Surface

Auger-electron spectroscopy was used to study oxygen adsorption on C₆₀ molecules film on (100)Mo. It appeares that one monolayer of C₆₀ molecules does not completely protect metal substrate from oxidation, and one needs thin C₆₀ film with thickness of 2-3 ML for complete reduction of oxygen penetration to the substrate from gas phase.     

Conformations of satellite DNAs

X-ray fiber diffraction studies of satellite DNAs from Gecarcinus lateralis, Drosophila virilis and Mus musculus, all of which have highly repetitious base sequences but with different degrees of sequence complexity, reveal only classical polynucleotide duplex structures in contrast to some highly repetitious synthetic DNAs.     

Efficiency and mode discrimination of a linear array of square CO2 waveguide lasers phase-coupled by an intracavity spatialfilter

In this paper, we present a theoretical analysis of a linear array of square waveguide CO₂ lasers phase-coupled with an intracavity spatial filter. Using a Rigrod-like method, we calculate the efficiency of the device and analyze its capability to discriminate between the fundamental mode and the transverse modes of both the array and the individual square waveguide     

Videokeratoscope for accurate and detailed measurement of the cornea surface

A videokeratoscope based on the imaging of a gridlike pattern is introduced. Unlike conventional videokeratoscopes that rely on Placido disks, the new measurement principle allows an exact reconstruction of the surface and the display of fine details. The experimental instrument was tested on precision glass spheres; the maximum error of the height data was less than 3 microm. The sensitivity and the potential to resolve fine details were demonstrated with irregular surfaces of specially prepared contact lenses. Structures with height deviations of 0.1 microm are well identifiable. The eyes of 18 individuals were investigated, and fine structures were found on these cornea surfaces. Conventional videokeratoscopes do not resolve such detail.     

Biomimetic mineral-organic composite scaffolds with controlled internal architecture

Bone and cartilage generation by three-dimensional scaffolds is one of the promising techniques in tissue engineering. One approach is to generate histologically and functionally normal tissue by delivering healthy cells in biocompatible scaffolds. These scaffolds provide the necessary support for cells to proliferate and maintain their differentiated function, and their architecture defines the ultimate shape. Rapid prototyping (RP) is a technology by which a complex 3-dimensional (3D) structure can be produced indirectly from computer aided design (CAD). The present study aims at developing a 3D organic-inorganic composite scaffold with defined internal architecture by a RP method utilizing a 3D printer to produce wax molds. The composite scaffolds consisting of chitosan and hydroxyapatite were prepared using soluble wax molds. The behaviour and response of MC3T3-E1 pre-osteoblast cells on the scaffolds was studied. During a culture period of two and three weeks, cell proliferation and in-growth were observed by phase contrast light microscopy, histological staining and electron microscopy. The Giemsa and G?m?ri staining of the cells cultured on scaffolds showed that the cells proliferated not only on the surface, but also filled the micro pores of the scaffolds and produced extracellular matrix within the pores. The electron micrographs showed that the cells covering the surface of the struts were flattened and grew from the periphery into the middle region of the pores.     

On the synthesis of linear control systems with specified characteristics

The Popov invariants are used to define two matrices M_AB and K_AB, which describe the properties of a system $\text{x}\text{?}\text{= Ax + Bu}$ in a basis-independent form. Also a control system with state feedback K and nonsingular input transformation M, $\text{x}\text{?}\text{= (A ? BK)x + BMw = Fx + Gw}$, can be uniquely specified by the corresponding matrices M_FG and K_FG, which may be chosen arbitrarily with the only condition, that (F, G) must have the same unordered set of Kronecker invariants as (A, B). It is shown, how K and M are computed from M_AB, K_AB, M_FG and K_FG. Implications for pole assignment, minimal polynomial assignment and observer design are shown. Also a solution to the minimal realization problem is given, which results in M_AB, K_AB and the output relation y = Cx.