Effects of Diphenyl Dichalcogenides on the Radical Polymerization of Diethynyl Disulfide Derivative

Radical reaction of bis(4-prop-2-ynyloxyphenyl) disulfide (1) with 2,2′-azobis(isobutyronitrile) as an initiator provided a polymer with dithioalkene units (2). The ¹H and ¹³C NMR spectra of 2 showed that 2 had mainly E-form dithioalkene structure. The radical reactions of 1 and diphenyl diselenide (3) or diphenyl ditelluride (5) were also carried out. At higher temperature than 70 °C, polymers were obtained with less amount of AIBN than in the case of the homopolymerization of 1. Addition of 3 or 5 in the reaction mixture appeared to promote the radical reaction. Moreover, the obtained structure has high contents of thio-seleno alkene or thio-telluro alkene than expected, which is due to difference of the chalcogen radical reactivity and difference of capture ability of the dichalcogenide.

Influence of fabrication conditions on the structural characteristics and the magnetic properties of FeAl2O4

We report a systematic evaluation of the magnetic properties of FeAl₂O₄ focusing on the relationship between the fabrication conditions and its structural characteristics, in order to improve ceramics processing in applications of this material. For this purpose, the most important factor to control is the inversion parameter, expressed as y in the (Fe_1−yAl_y)(Al_1−y/2Fe_y/2)₂O₄ composition, which is relatively high for the spinel aluminate of a transition metal. The magnetic properties of these samples all show the spin glass phenomenon at low temperatures, and the cusp temperature depends systematically on this y value. This means that the evaluation of these magnetic properties will be an effective way to predict some characteristics of product FeAl₂O₄. Additionally, this study found an anomaly in the structural and magnetic characteristics of FeAl₂O₄ fabricated at a low temperature. This is thought to originate in a tiny and a small amount of impurity. It will be key for discussing the quality of chemically synthesized FeAl₂O₄, which is typically produced at low temperatures.     

High pressure form of fluoride garnets Na3M2Li3F12 (M=Al & Fe)

The fluoride garnet, Na₃Fe₂Li₃F₁₂, transforms to a single phase with the cryolite (ordered perovskite) structure under 60 kb above 400°C. The lattice constants, a=5.338, b=5.498, c=7.666 Å and β=90.0°, are smaller than those of Na₃FeF₆, due to the substitution of Na for Li ions in the structure. The measurements of magnetic susceptibility and Mössbauer effect indicate that Fe ions are in the high spin trivalent state and in octahedral site. Na₃Al₂Li₃F₁₂, cryolithionite, decomposes to the cryolite and α-Li₃AlF₆ under high pressures examined.     

Synthesis and Properties of Cross-Linked Poly(vinylene-arsine)

Summary Cross-linked poly(vinylene-arsine)s (4) were synthesized by a free-radical terpolymerization of phenylacetylene (2), hexaphenylcyclohexaarsine (l), and p- or m-diethynylbenzene (p- or m-3) at different compositions in the presence of a catalytic amount of AIBN. The number-average molecular weights of the resulting polymers were a few thousands estimated by gel permeation chromatography (GPC) analysis. By gas chromatography (GC) analysis p-3 was found to be more reactive during the polymerization than m-3 and the resulting cross-linked polymer (p-4) showed lower solubility than that of m-4. The cross-linked poly(vinylene-arsine)s showed higher glass transition temperature in the measurement of differential scanning calorimetry (DSC) and more red-shifted emission in chloroform solution than that of the linear poly(vinylene-arsine). These properties could be tuned by varying the monomer feed ratio.     

Assessment of psychosocial stressors and maladjustment among foreign students of the University of the Ryukyus

Hormone replacement therapy: determinants of women's decisions. The purpose of this qualitative study was to explore the decision-making process used by menopausal women initiating or remaining on hormone replacement therapy (HRT), stopping HRT, or never starting HRT. Eight focus groups, composed of women reflecting these categories, were conducted. Four major themes or spheres of influence emerged as important in the women's decision-making process: the woman's internal influence--the interface between her perceptions and feelings including the symptoms of menopause, the benefits realized by HRT usage, and the experiences of negative side effects; interpersonal relationships, including the patient-physician relationship, family, friends and information networks; external influences, such as ageism and sexism; and consequences resulting from whichever treatment decision was chosen. A new concept was elucidated called "weighted influence" to underscore the dynamic interplay among the spheres. As information about HRT continues to grow and change, an understanding and application of these spheres of influence can assist physicians in engaging in a dialogue with their patients that allows individual evaluation and application of this new information.     

A hybrid particle swarm optimization for distribution state estimation

This paper proposes a hybrid particle swarm optimization (HPSO) for a practical distribution state estimation. The proposed method considers nonlinear characteristics of the practical equipment and actual limited measurements in distribution systems. The method can estimate load and distributed generation output values at each node by minimizing the difference between measured and calculated voltages and currents. The feasibility of the proposed method is demonstrated and compared with an original particle swarm optimization-based method on practical distribution system models. Effectiveness of the constriction factor approach of particle swarm optimization is also investigated. The results indicate the applicability of the proposed state estimation method to the practical distribution systems.