Evaluation of protein adsorption on hydrogenated amorphous carbon films by surface plasmon resonance phenomenon

To develop an anti-thrombogenic coating, hydrogenated amorphous carbon (a-C:H) and related films were studied in terms of their protein adsorption during the initial process in thrombogenesis by surface plasmon resonance (SPR) phenomenon using a multilayer device consisting of an a-C:H layer on Au. Two a-C:H films with different hydrogen contents, a nitrogenated a-C:H (a-C:N:H) and a fluorinated amorphous carbon (a-C:F) film were prepared on the Au layer in the multilayer device. Human serum albumin (HSA) in a phosphor buffer (PB) was used as a protein. Na₂HPO₄·12H₂O, NaH₂PO₄·2H₂O and deionized water were mixed to coordinate PB. From the attenuation of reflected light, the SPR angle was determined to the angle at minimum reflection intensity. The observed behavior of the SPR angle indicated that HSA was adsorbed on all films. The SPR angle was analyzed to estimate the multilayer index of the HSA-adsorbed layer on each film. The HSA adsorption ability of both a-C:H and a-C:N:H films was similar, and the absorption ability of the a-C:F film was lower than that of the other films. Hence, the surface polarization dominates the adsorption ability of HSA on a-C:H films and related film.     

Friction anchor welding between Al alloy and Zn-coated steel using insert steel difference in the mechanism of friction anchor welding between the types of Zn coatings on Zn-coated steel

The lap joints of upper Al alloy sheets (1.0-mm-thick A5052) and lower Zn-coated steel sheets (1.2-mm-thick GI steel or GA steel) were welded using insert steel sheets (0.6-mm-thick SPCC) by a spot welding process with a tool having a spherical ceramic tip, i.e. ‘Friction Anchor Welding.’ As a result, straight (not-rugged) steel projections were formed in the Al alloy sheets for both the GI and GA, while steel projections were not formed for the GI, rugged steel projections were formed for the GA without the insert steel sheets. In addition, the tensile shear strength for the GI was greater than that for the GA. In other words, the tensile shear strengths reached about 3.9 kN/point for the GI and about 3.2 kN/point for the GA, which were greater than those of the welds without the insert steel sheets. On the other hand, the cross tensile strengths for the GI and GA were almost the same, which reached about 2.6 kN/point. Additionally, for the GI, the Zn layer on the GI steel sheet melted and was totally removed due to the pressure and heat caused by the rotating tool, which facilitated the welding between the SPCC and GI steel sheets. For the GA, however, the Zn-Fe layer on the GA steel sheet changed to a solid-liquid mixture and was not completely removed, which prevented the welding between the SPCC and GA steel sheets. Therefore, the thickness of the steel-steel welded region (i.e. the SPCC-GI or the SPCC-GA welded region) for the GI was greater than that for the GA. We estimated that the difference in this thickness is significantly related to the fracture mechanism during the tensile shear test and the cross tensile test.     

Fabrication of a Composite Varistor with Electrical Conductive Ni Filler and Electrostriction PNZST Matrix

A composite varistor was fabricated using Ni powder as conductive filler and PNZST antiferroelectric powder as electrostriction matrix. The composite is an electrical insulating material when an electrical field is not applied. When the electrical field was applied to the composite, the PNZST powder matrix was distorted. A conduction path was formed in the composite because of the distortion of the electrostriction matrix and thus the composite became a conductive material when the electrical field was applied. Composites using an Ni filler with 4-μm particle size and a PNZST matrix with 2-μm particle size showed a varistor property with volume fractions 33% and 37%; the nonlinearity coefficients of the composites were 3.85 and 3.82. The composites using an Ni filler with 40-μm particle size and a PNZST matrix with 2-μm particle size also showed varistor properties with volume fractions 50% and 53%, and nonlinearity coefficients of the composites were 3.65 and 3.12.     

Film designed for lubricative coated steel sheets

This paper reports on a film designed for lubricative coated steel sheets which has excellent die galling resistance even during conducting of continuous press forming under severe conditions. Our newly developed film whose self-crosslinked structure was formed with a silanol group can retain a high modulus even up to when a high temperature is attained and that it has excellent die galling resistance even during continuous press forming.     

Preparation of Transparent Conductive (ZnO)mIn2O3 Fine Powder by Gel-Combustion Reaction

A fine powder of (ZnO) _m In₂O₃ ( m =3, 4) was obtained by the self-combustion reaction, under firing at a furnace temperature of 350°C in a nitrogen atmosphere, of a gel prepared from a mixed zinc and indium nitrate aqueous solution peptized with citric acid. A (ZnO)₃In₂O₃ single-phase product was obtained when citric acid was substituted by glycine, because the combustion temperature of glycine mixture is >1260°C. The highest electrical conductivity, 0.2 S cm⁻¹, was obtained in a tin-substituted, transparent conducting (ZnO) _m In₂O₃ product, where m =3 and 4.     

Generation mechanism of polygonal wear of work rolls in a hot leveler and a countermeasure by dynamic absorbers

This paper deals with the polygonal deformation phenomena of work rolls in a reversible hot plate leveler. According to the measurements of deformed rolls and the vibration measurement, a simple model regarding the polygonal deformation as unstable vibration caused by time retardation accompanied by wear on the surfaces of the rolls is proposed. Also, the modal analysis is applied to a general system with time retardation accompanied by wear in order to obtain the equations of motion for each mode and to derive some important parameters. Furthermore, a countermeasure for the polygonal deformation by using dynamic absorbers is considered. The optimal design of a dynamic absorber mounted on a single degree-of-freedom system where the polygonal wear is generated is discussed by applying the optimal design procedure of a dynamic absorber for forced vibration to this self-excited vibration system. As a result, a design in which the system is perfectly stabilized is obtained. This result is applied to a hot leveler as a two degree-of-freedom system through the modal analysis. By numerical analysis, it is confirmed that the hot leveler changes into a perfectly stable system by two dynamic absorbers, and the polygonal wear is not generated at all.     

BAMO/NMMO Copolymer with Polyester Initiation

In order to improve of mechanical properties at low temperature region, 3,3-bis(azidomethyl)oxetan (BAMO), 3-nitratomethyl-3-methyloxetane (NMMO) and polyester (PE) copolymer were synthesized by using polyester initiator with boron trifluoride etherate. The molar ratio of each units in the BAMO/NMMO/PE copolymer was 7.4/2.6/0.39 according to the ¹H-NMR spectrum analysis and was almost exactly the same composition as the monomer fed (7/3/0.33). The relative composition of triad microstructures was same as theoretical value and they were randomly arranged. The PE, which was a replacement of 1,4-butanediol, acted as an excellent soft segment in the copolymer, and the glass transition point of the elastomer was 4.8 degrees lowered by the replacement. This effect was also verified in the mechanical properties of the composite propellant and the tensile elongation was increased from 15% to 40%percnt; at −40 °C.