The extent of strength in the club filters

In this paper we consider whether the minimal normal filter onP _κλ, the club filter, can have strong properties like saturation, pre-saturation, or cardinal preserving. We prove in a number of cases that the answer is no. In the case of saturation, Foreman and Magidor prove the answer is always no (except in the caseκ =λ = ℵ₁—and in this case saturation is known to be consistent). The first author was partially supported by NSF grant DMS-9626212.     

X-ray absorption fine-structure study on the fine structure of lutetium segregated at grain boundaries in fine-grained polycrystalline alumina

Local atomic structures around the Lu³⁺ ion in a 0.1?mol%?LuO_1.5-doped fine-grained Al₂O₃, in which the doped Lu³⁺ ions segregate to the grain boundaries, was characterized by Lu L₃-edge X-ray absorption fine structure. Structural parameters in LuO_1.5-doped Al₂O₃ were determined by a curve-fitting method, and the results showed that six O^2? ions coordinate with the Lu ion in LuO_1.5-doped Al₂O₃. In addition, it was also revealed that the Lu–O interatomic distance in Lu-doped Al₂O₃ was close to that in Lu₂O₃, which was about 19% longer than the Al–O interatomic distance in undoped Al₂O₃. The present results indicated that the local atomic structures around Lu in Al₂O₃ are close to that in Lu₂O₃. It is thus supposed that atomic distances between Al³⁺ and O^2? ions in the vicinity of Lu-segregated grain boundaries are shortened in comparison with that in undoped Al₂O₃. A first-principles molecular orbital calculation was performed for the [Al₂O₉]^?12 model cluster, and the shortening of the Al–O interatomic distance was found to have an effect of increasing the ionicity in Al³⁺ ions.     

Target Residues from the Interaction of Copper with 40MeV/u 40Ar Ions

Cross Sections and average forward recoil range FW were measured for target residues from the interaction of Cu with 40MeV/u ⁴⁰Ar ions using off-line y-ray spectroscopy.The mass yield distribution was obtained with assumption of charge distribution.The linear momentum transfer was calculated from FW values.A comparison with similar results of ¹²C+Cu and ²⁰Ne+Cu reactions indicates that the fractional linear momentum transfer,corresponding to central collisions,decreases with increasing projectile mass at the same energy per nucleon. However,the excitation energy of the composite system created from the collisions of Cu with ⁴⁰Ar ions reached the value of 5.3MeV /u and was higher than those from the collisions with ¹²C and ²⁰Ne ions.     

Stereospecific polymerization of 1‐hexene catalyzed by ansa‐metallocene/methylaluminoxane systems under high pressures

Stereospecific polymerization of 1‐hexene under high pressures (up to 1,000 MPa = ca. 10,000 atm) using metallocene/methylaluminoxane (MAO) catalysts was investigated. Several C₂‐symmetric ansa‐metallocenes, their meso‐isomers, and two C_s‐symmetric ansa‐metallocenes were employed as catalyst precursors. In the course of this study, novel C₂‐symmetric germylene‐bridged ansa‐metallocenes, (rac‐[Me₂Ge(η⁵‐C₅H‐2,3,5‐Me₃)₂MCl₂] (M = Zr, rac‐4a; M = Hf, rac‐4b), have been prepared. High pressures induced enhancement of the catalytic activity and the molecular weight of the polymers in most of the catalysts. The maximum of both the catalytic activity and the molecular weight of the polymers was mostly observed at 100–500 MPa in each catalyst, although the enhanced ratio was smaller than that observed for nonbridged metallocenes. Isospecificity of the C₂‐symmetric ansa‐metallocene catalysts was essentially maintained even under high pressure. Highly isotactic polyhexene ([mmmm] = 91.6%) with very high molecular weight (M_w = 2,360,000) was achieved by rac‐4b under 250 MPa. High pressures slightly decreased syndiotacticity when the C_s‐symmetric ansa‐metallocene, isopropylidene(1‐η⁵‐cyclopentadienyl)(9‐η⁵‐fluorenyl)zirconium dichloride 5, was employed. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 283–292, 1999     

Association Between Social Network and Physical Function in Community-Dwelling Older Adults in Japan

Objective: A poor social network and the decline of physical function are known to be critical risk factors for functional decline in older adults. The aim of this study was to investigate the relationships between social network and physical function in Japanese community-dwelling older adults. Methods: Participants were 339 adults aged 65 years or older (mean age : 73.0 years, women :70.2%), living independently in their communities. A self-reported questionnaire was used to assess social network on two different scales―the 6-item Lubben Social Network Scale (6LSNS) and frequency of contact with other people. Handgrip strength, knee extension strength, gait speed, Timed Up and Go Test (TUG) results, and 5-repetition chair stand test (CST) scores were used to determine physical function. A multiple regression analysis that adjusted for confounding factors was used to analyze the relationship between the social network scales and each physical function test. Results: According to the results of a multiple regression analysis, a high 6LSNS score was significantly associated with greater handgrip strength (B = 0.63, p = 0.03), faster CST (B = −0.23, p = 0.01), and faster TUG (B = −0.12, p = 0.03), and high frequency of contact was significantly associated with greater handgrip strength (B = 1.08, p = 0.01). Conclusions: Social network was associated with muscle strength and physical performance. Consequently, older adults with poor social networks require an assessment of physical function, since their physical functions have possibly deteriorated.     

A test of the new “integrated MO + MM” (IMOMM) method for the conformational energy of ethane and n-butane

Test calculations of the newly developed “Integrated Molecular Orbital + Molecular Mechanics” (IMOMM) method were performed for the optimized equilibrium and transition structures and energies of ethane and n-butane. In this method, the total energy of a large molecular system is expressed as a sum of the MO energy of the small “model” system and a modified MM energy of the “real” system, and full geometry optimization is carried out using the gradient of this total energy. Various schemes of partition of the system into the MO part and the MM part, including some not intended in the original design of the method, were examined and compared with the pure ab initio MO and the pure MM results. In most reasonable partition schemes, the IMOMM method can reproduce the pure ab initio and the pure MM geometries and energies quite well. © 1996 John Wiley & Sons, Inc.     

High preconcentration of ultra-trace metal ions by liquid–liquid extraction using water/oil/water emulsions as liquid surfactant membranes

A high preconcentration method by liquid–liquid extraction using liquid surfactant membranes was developed. The water-in-oil (w/o) emulsion containing dilute hydrochloric acid, 2-ethylhexyl hydrogen 2-ethylhexylphosphonate (PC-88A), liquid paraffin, and kerosene was used for the extraction. In a resulting volume of 1000 cm³ of an aqueous sample solution (pH 5.0) containing less than 1 mg of each metal ion, 2 cm³ of w/o emulsion droplets coated with sorbitan monooleate were dispersed. The analyte metal ions in the outer bulk aqueous phase were extracted into the organic phase to form a complex with PC-88A and successively back-extracted into the inner aqueous phase. The analytes in the resulting inner aqueous phase were determined subsequently by graphite furnace atomic absorption spectrometry applied as a detector. By this procedure, concentration factors of 570, 820, 750, 970, 860, and 880 were achieved for chromium(III), manganese(II), cobalt(II), nickel(II), copper(II), and cadmium(II), respectively, and also the respective detection limits (3σ) of 0.4, 20, 1.2, 18, 18, and 0.7 pg cm⁻³ were obtained.