DLC (Diamond-like carbon) films are excellent in the physical characteristic or the mechanical properties. These are mainly used for the industrial materials. Additionally, DLC films have outstanding antithrombogenicity and good biocompatibility. Therefore DLC films are very expected as biomaterials.
In order to evaluate the blood compatibility of DLC films, the hemolytic of DLC films deposited on several kinds of polymeric materials (Silicone, Polycarbonate, Polyvinyl chloride) has been investigated. Test circuit of blood flow carried out the in-vitro test, and free hemoglobin was determined by colorimetric assay method. The physical and chemical properties of DLC films were estimated by Atomic force microscopy, Slip-test, Raman spectroscopy, and Xray photoelectron spectroscopy. The DLC films coating dramatically decreased the hemolytic of the all-polymeric samples. The effect of hemolytic is originated by the physical and chemical improvement of the polymeric surfaces and the reduction of friction.
DLC films are greatly expected as a means of the surface treatment of biomaterials.

抄録全体を表示

The stage-1 alkali metal-graphite intercalation compounds, MC₈ (M=K, Rb, Cs), were prepared from Grafoil, and then ternary compounds were obtained by additional intercalation of ammonia. The electrical conductivity of those compounds were determined. The conductivity of KC₈ decreased considerably along with ammoniation in the region of ammonia content, n_NH3/nK, less than 0.2. Similar behavior of conductivity change was also observed for RbC₈ for nNH₃ / n K≤ 0.4, except for slight decrease in the early stage up to nNH₃/nK=0.1. In contrast, the conductivity of CsC₈ decreased slightly by ammoniation in the region of nNH₃/nK≤0.6.

抄録全体を表示

Inter-laminar shear strengths (ILSSs) of two types of C/C composites and two types of Tyrannohex were measured as a function of strain rate. Charpy impact test machine can be used to measure ILSS for dynamic tensile loading in double notched configuration. ILSS of the unidirectional C/C composite was nearly constant at the strain rates ranging from 1.6×10^-5/s to 617/s, while that of cross-ply C/C composite increased with the rate. On the contrary, ILSSs of the both types of Tyrannohex decreased at the higher strain rates. For the unidirectional C/C composite, the crack propagation velocity could be measured using crack gages. The velocity of a crack which appeared between the double notches increased with the strain rate; 480m/s at 1.6×10^-5/s and 1, 400m/s, at 1.6×10^-1/s. The propagation veloc-ity of the crack at higher strain rates above 1.6×10^-1/s could not be measured, because the crack gages failed to respond to the crack propagation in velocity.

抄録全体を表示

Neutron sources and the consequent time-of-flight diffraction techniques provide the precise short-range structure.Recently mechanical alloying (MA) has been employed to synthesize various kinds of materials. The MA of graphite under Ar gas atmosphere transformed the hexagonal graphite into nano-structured graphite. In case of the mechanical alloying of the graphite under D₂ gas atmosphere, deuterium was absorbed by the solid-gas reaction. The radial distri-bution function RDF (γ) derived by neutron diffraction experiments informed us the location of deuterium in the nano-structured graphite. The short-range structure of lithium-graphite intercalation compound observed by neutron dif-fraction indicated the formation of metastable LiC_3.1 intercalation compound.

抄録全体を表示