Development of small bulge fatigue testing technique using small disk‐type specimen

A new fatigue testing technique, the small bulge fatigue (SBF) test using a small disk‐type specimen with flat and concave surfaces, was developed in this study. In the technique, a cyclic oil pressure could be alternatively applied to both specimen surfaces at the frequency of 10 Hz. After some verification tests for the displacement and strain measurements, type 316 austenitic stainless steel specimens were subjected to a preliminary test using this newly developed testing technique. As a result, the SBF test results (S‐N curve) were in good agreement with those of conventional fatigue tests by defining fatigue life as the number of cycles to the sudden drop in oil pressure because of fracture.     

Polymerization of 4-n-alkylstyrenes with typical Ziegler-Natta and metallocene catalysts

Polymerization of 4-n-alkylstyrenes (alkyl side group; methyl, ethyl, propyl and buthyl) was carried out with the η-C₅(CH₃)₅TiCl₃-methylaluminoxane (MAO) and TiCl₃-triethylaluminum (TEA) catalyst systems. When the η-C₅(CH₃)₅TiCl₃-MAO catalyst was used, the stereoregularity of resulting polymers markedly depended on the length of substituted alkyl groups, i.e., the catalyst gave highly syndiotactic poly(4-methylstyrene), but produced atactic polymers for the monomers with ethyl, propyl and buthyl substituents. On the other hand, all the poly(4-n-alkylstyrene)s obtained with the TiCl₃-TEA catalyst were highly isotactic. As a result, a large difference was observed in the thermal properties of polymers obtained between the two catalyst systems. Received: 6 September 1996/Accepted: 16 October 1996     

A knowledge representation and inference system for procedural law

KRIP-2 is a name of a software tool for building expert systems of a legal problem. It was developed to build an expert system for the Patent Law. Laws can be classified into the substantive laws and the procedural laws, and the Patent Law contains both of them. As these laws have different features, it is inconvenient to develop the knowledge base of these in the same knowledge representation. To develop a knowledge base of laws, a knowledge representation language KRIP/L was introduced. KRIP/L was an integration of the object oriented concept and extended Prolog, and has useful mechanisms to describe the phenomena occured in the legal problem. KRIP/L-2 is the second version of KRIP/L. KRIP-2 is an implementation of KRIP/L-2, and composed of some utility modules. KRIP-2 is implemented in Prolog, and an expert system for the Patent Law is developed in KRIP-2.     

Lithium–Iron Fluoride Battery with In Situ Surface Protection

Lithium–metal fluoride (MF) batteries offer the highest theoretical energy density, exceeding that of the sulfur–lithium cells. However, conversion‐type MF cathodes suffer from high resistance, small capacity utilization at room temperature, irreversible structural changes, and rapid capacity fading with cycling. In this study, the successful application of the approach to overcome such limitations and dramatically enhance electrochemical performance of Li–MF cells is reported. By using iron fluoride (FeF₂) as an example, Li–MF cells capable of achieving near‐theoretical capacity utilization are shown when MF is infiltrated into the carbon mesopores. Most importantly, the ability of electrolytes based on the lithium bis(fluorosulfonyl)imide (LiFSI) salt is presented to successfully prevent the cathode dissolution and leaching via in situ formation of a Li ion permeable protective surface layer. This layer forms as a result of electrolyte reduction/oxidation reactions during the first cycle of the conversion reaction, thus minimizing the capacity losses during cycling. Postmortem analysis shows the absence of Li dendrites, which is important for safer use of Li metal anodes. As a result, Li–FeF₂ cells demonstrate over 1000 stable cycles. Quantum chemistry calculations and postmortem analysis provide insights into the mechanisms of the passivation layer formation and the performance boost.     

Molten-Salt Synthesis and Characterization of Nickel-Doped Forsterite Nanocrystals

Nickel-doped forsterite (Ni²⁺:Mg₂SiO₄) nanocrystals have been synthesized by a facile molten-salt approach in the presence of NaCl and a surfactant (NP-7.5). The products were characterized by X-ray diffraction, transmission electron microscopy (TEM), high-resolution TEM, selected area electron diffraction (SAED), and luminescence spectra measurements. The crystal size could be controlled by tailoring the synthesis parameters. TEM, high-resolution TEM, and SAED results revealed the single crystalline character of Mg₂SiO₄ nanoparticles. A possible model for the growth of Ni²⁺:Mg₂SiO₄ nanocrystals was postulated. The obtained Ni²⁺:Mg₂SiO₄ nanocrystals show strong, super broad, near-infrared luminescence at room temperature. These doped Mg₂SiO₄ nanocrystals are promising gain mediums for super broadband optical amplification.     

Influence of structural organization on tensile properties in mesomorphic isotactic polypropylene

The effects of annealing on the structure and mechanical properties of mesomorphic isotactic polypropylene have been investigated using wide-angle and small-angle X-ray scattering and rheo-optics in addition to tensile tests. Young's modulus of mesomorphic phase was estimated to be 5 GPa using Takayanagi model. The α-crystallitic iPP prepared by annealing the quenched mesomorphic iPP was transparent because of the absence of spherulitic structure. It was found that the mechanical yielding of α-crystallitic iPP is dominated by the plastic flow of crystalline structural units whereas the yield process of α-spherulitic iPP quenched at 80 °C is caused by the fracture or fragmentation of crystalline structural units.     

Dynamic properties of an organic hybrid of chlorinated polyethylene and hindered phenol compound

The dynamic mechanical properties of hybrids of chlorinated polyethylene (CPE) and 3,9‐bis[1,1‐dimethyl‐2{β‐(3‐tert‐butyl‐4‐hydroxy‐5‐methylphenyl)propionyloxy}ethyl]‐2,4,8,10‐tetraoxaspiro[5,5]‐undecane (AO‐80) were investigated. The CPE/AO‐80 hybrids showed a novel relaxation in addition to the glass transition of CPE. The novel relaxation is attributed to the dissociation of intermolecular hydrogen bonds within the AO‐80–rich domain. The Payne effect, that is, the decrease of the storage modulus E′ with increasing strain amplitude and the appearance of a loss modulus E″ maximum at a strain of 0.6%, was observed for the CPE/AO‐80 hybrids. This result demonstrates that the AO‐80–rich domains within matrix polymer CPE form a network. The Payne effect is considered to be attributed to the mechanical disruption of segment–segment contacts at a sufficiently great strain. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1788–1793, 2001     

Extraction of the Mayer wave component in blood pressure from the instantaneous phase difference between electrocardiograms and photoplethysmograms

To analyze the human baroreflex function noninvasively, a beat-by-beat blood pressure signal is often measured by tonometry or plethysmogram using continuous blood pressure sensors. However, these sensors are too expensive and bulky to be used for home healthcare or telemedicine. On the other hand, it is well known that the pulse transmission time (PTT) is strongly correlated with the beat-by-beat blood pressure, especially in the Mayer wave-related frequency band (0.05–0.15 Hz). To obtain a new physiological parameter with a higher correlation with blood pressure in this band compared with that obtained using the PTT alone, we proposed the samephase temporal difference (SPTD) based on electrocardiogram and photoplethysmogram signals. By examining 94 healthy subjects using a combination of SPTD and conventional PTT, it was revealed that the correlation with blood pressure for 25 subjects could be improved using the SPTD instead of the PTT, by applying the criterion of the ratio of their powers. However, for 7 subjects, the correlation decreased.     

Hyphal surface architecture and cell morphology of Trichoderma reesei

The filamentous fungus Trichoderma reesei which is known to secrete high amounts of cellulolytic enzymes was found to produce a massive amount of fibrous material at the outer surface of the cell wall as observed by ultrahigh-resolution low-voltage scanning electron microscopy. Using transmission electron microscopy, the cell wall ornamentation of the hyper-cellulosic mutant PC-3-7 was found to be less massive and much thinner than for QM9414. A significant amount of fibrous material was produced in Avicel-grown cultures that were less abundant in glucose-grown cultures and Avicel was occasionally found entangled within the cell wall-associated fibrous layer.