On a contact 3-structure

A contact 3-structure consists of three contact metric structures which satisfy the relation (2.1). On a product manifold of the real line and a manifold with a contact 3-structure, we can construct three almost Hermitian structures satisfying the quaternionic identities. From this view point we discuss a contact 3-structure. Owing to Hitchin's well known Lemma concerning to hyperk?hler structure (Lemma H), we show that a contact 3-structure is necessarily a Sasakian 3-structure. Received: 26 August 1999; in final form: 2 May 2000 / Published online: 4 May 2001     

Tip cleaning and sharpening processes for noncontact atomic force microscope in ultrahigh vacuum

Tip cleaning and sharpening processes for noncontact atomic force microscope (AFM) operated in ultrahigh vacuum (UHV) were carried out and evaluated by a scanning Auger microscope (SAM) with a field emission electron gun and a noncontact AFM in UHV combined with a scanning tunneling microscope and a field emission microscope. The cantilever used in this study was piezoresistive, which can be heated by passing a current through the resistive legs of the cantilever. As a pretreatment, the tip was irradiated with ultraviolet light in oxygen to remove carbon contaminants. It was heated at about 750°C to form a clean oxide layer in oxygen of 5×10⁻⁵ Torr in an SAM chamber. The desorption of the layer can make a remained tip apex sharper by heating under electron beam irradiation. A thermally oxidized layer was also eliminated by HF etching to sharpen the tip apex. The procedures are useful to obtain a well-defined Si tip suitable for a noncontact AFM.     

Flexible thermoelectric materials based on conducting polymers doped with silicone polymer electrolyte

Abstract

Novel conducting polymers doped with siloxane-based polyanion have been synthesized and their mechanical and thermoelectric properties were investigated. Free-standing properties and flexibility of these polymer films were compared with conducting polymers doped with conventional polyanion composed of carbon-carbon backbone. Thermoelectric properties were found to not be affected by the chemical structures of dopant polyanions.     

Preparation of ionic liquid-encapsulated polymer particles

Encapsulation of ionic liquid, 1-hexyl-3-methylimidazolium bis(trifluoromethane sulfonyl)amide ([Hmim][TFSA]), was carried out by microsuspension polymerization of ethylene glycol dimethacrylate (EGDM) utilizing the self-assembling of phase-separated polymer method, which had been proposed by us for the preparation of hollow polymer particles. After the optimization of the polymerization conditions, ionic liquid-encapsulated polymer particles, which have smooth surface morphology and a single hollow structure, were successfully prepared. Encapsulation efficiency of [Hmim][TFSA] was significantly improved from about 20–70 % by changing the shell polymer from polyEGDM homopolymer to poly(EGDM-butyl methacrylate) (50/50, w/w) copolymer, which was likely to have relatively low affinity for [Hmim][TFSA]. Additionally, ionic liquid-encapsulated polymer particles displaying ionic conductivity were successfully prepared using triethylene glycol dimethacrylate as divinyl monomer instead of EGDM.     

A Novel Estimation Method of the Distribution of Carboxyl Groups Within Copolymer Particles Using Isothermal Titration Calorimeter

Summary: A novel quantitative method using isothermal titration calorimeter (ITC) for the estimation of the distribution of carboxyl groups within polymer particles has been proposed. The method has been employed to clarify the difference in the distribution between the particles prepared by batch emulsion copolymerization of styrene and methacrylic acid under inefficient and efficient stirring conditions. At inefficient stirring, monomer was floating as a layer on the aqueous medium, whereas at efficient stirring, the monomer phase was dispersed as droplets. Under inefficient stirring, methacrylic acid (MAA) polymerized faster than styrene (S) due to a slower diffusion rate of S than MAA into the aqueous medium, while under efficient stirring, S and MAA copolymerized at similar rates. ITC measurement showed that under inefficient stirring, the carboxyl groups were distributed mainly in the center of the particles, and their number decreased toward the surface. On the other hand, under efficient stirring, carboxyl groups were distributed homogeneously inside the particle.