Effective thickness of adsorbed polymer in a shear field

The effective thickness of the adsorbed polymer layer in a linear shear field was investigated theoretically. It is found that, when the shear strength is weaker than a certain critical value, distribution of segments perpendicular to the field is unaltered from that at equilibrium, but when the shear strength goes over the critical value, the distribution changes abruptly according to the nature of the adsorption.     

Conformational stability of poly(trimethylene sulphide)

CNDO/2 calculations with the spd basis set using the tight-binding approximation for polymers were performed on species of poly(trimethylene sulphide) (PTM3), assuming several typical molecular conformations. From the results of the calculations, the conformational stability of PTM3 is discussed in comparison with that of poly(trimethylene oxide) (POM3).     

Characterization of Cu(InxGa1−x)2Se3.5 thin films prepared by rf sputtering

Cu(In_xGa_1−x)₂Se_3.5 thin films were fabricated by rf sputtering from CuIn_xGa_1−xSe₂ and Na mixture target by controlling the mixture ratio. X-ray diffraction analyses show that the structure of Cu(In_xGa_1−x)₂Se_3.5, thin films is different from chalcopyrite structure: especially, CuIn₂Se_3.5 thin films have a defect chalcopyrite structure. The lattice parameters for Cu(In_xGa_1−x)₂Se_3.5 thin film are slightly smaller than those for CuIn_xGa_1−xSe₂ thin film and linearly decreased with increasing Ga content. The optical absorption coefficients for Cu(In_xGa_1−x)₂Se_3.5, thin films exceed 2 × 10⁴ cm⁻¹ in energy region above the fundamental band edge. The band gap for Cu(In_xGa_1−x)₂Se_3.5 thin films is larger than that for CuIn.Ga_1−x2Se₂ with the same Ga content and increased with increasing Ga content.     

Correlation of fasting blood glucose and haemoglobin A1c measured with an automated analyser

A subtype of glycohaemoglobin, haemoglobin (Hb) A_1c, in specimens of whole blood was assayed on a new automated analyser that makes use of high-pressure liquid chromatography. The analyser provided precise and reproducible values. The mean of the HbA_1c values was lower than that with an older instrument. The mean tended to increase with the age of the subjects, who were undergoing routine health examinations. No sex difference was found. When measurement was made 1 h after the subjects drank 50g of glucose, the value of HbA_1c was unaffected. Correlation was strong between the HbA_1c value and the fasting blood glucose value, which suggested that fasting blood glucose could be estimated from the HbA_1c value.     

A method of qualitative reasoning for model-based problem solving and its application to a nuclear plant

Model-based expert systems are expected to contribute to overcoming the difficulties of conventional rule-based systems. This paper describes the modeling of mechanical systems and a method of qualitative reasoning based on causal specifications. The causal specifications represent a component's local causal properties, following the principles for reusability and composability. It contributes to providing intuitive causal ordering of complex behavior originated in the combination of components, including inter-component negative feedback. A model of a system is represented by combining a set of local component models and global knowledge derived from general properties of the physical entity. This allows for reusable knowledge which is easy to describe. Furthermore, the method has been successfully applied to a nuclear power plant. Reasoning results were unambiguous and matched those obtained by domain experts.     

Effect of oxide addition on the sintering and high-temperature strength of Si3N4 containing Y2O3

The effect of oxide addition on the sintering behaviour and high-temperature strength of Si₃N₄ containing Y₂O₃ was studied at 0.1 to 30 MPa N₂ at 1600 to 2000° C. The addition of oxide, i.e. MgO, Al₂O₃, La₂O₃, or Nd₂O₃, was found to lower the densification temperature and increase the densification rate. The addition of Al₂O₃ or MgO reduced the strength of sintered materials at >1350° C. The addition of La₂O₃ or Nd₂O₃, on the other hand, did not affect high-temperature strength which remained equivalent to that of the material containing only Y₂O₃. These results indicate that the glassy phases in these systems are as refractory as that in the Si₃N₄-Y₂O₃.     

On creep test loading for soft polymers

The dead-weight loading speed in the creep test for soft polymers was investigated. The optimum dead-weight loading speed can be determined so as to assure instantaneous elastic deformation and, at the same time, also avoid dynamic effects. It is found that small dynamic effects are inevitable for soft polymers such as polypropylene even at optimum speed. The experimentally determined optimum dead-weight loading speed for polypropylene was 300 mm/min for 30 kg dead-weight at 16°C.     

Surface structures of solvent‐cast films prepared from poly(ethylene oxide)‐segmented nylons

The surface structures of three kinds of poly(ethylene oxide)‐segmented nylon (PEO‐Ny) films prepared by the solvent‐cast method were investigated with electron spectroscopy for chemical analysis (ESCA). The PEO‐Ny's used were high‐crystalline PEO‐segmented poly(iminosebacoyliminohexamethylene), low‐crystalline PEO‐segmented poly(iminosebacoylimino‐m‐xylene), and amorphous PEO‐segmented poly(iminoisophthaloyliminomethylene‐1,3‐cyclohexylenemethylene), and the PEO contents in the bulk polymers were approximately 10 wt %. The ESCA results showed that the PEO segment was enriched on the top surfaces of all the films, and the degrees of enrichment were different. The mechanism of the PEO enrichment was examined. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 10–16, 2002