Adjacent track interference analysis of shielded perpendicular writers

In order to achieve high track density in perpendicular recording, write-field leakage from the main pole to adjacent tracks needs to be minimized. We used a 3-D finite-element method to investigate the optimal writer design, which minimizes fringing fields. We also confirmed the results using experimentally by studying adjacent track interference (ATI) on a spinstand. According to both modeling and experimental data, we found that ATI performance can be clearly improved with a wrap-around-shielded (WAS) writer while maintaining enough write-ability. In order to reduce the fringing field, a WAS having thick throat, high permeability and high saturated magnetic flux density was required. We also confirmed that variations of ATI performance due to flare length distributions can be effectively suppressed with the WAS writer.     

Nano-porous manganese oxide formed by self-assembled agglomeration of nanocrystallites

We synthesized specific nano-porous dendritic structures similar to cedar leaves of manganese oxides using pulsed laser ablation (PLA) process, with the potential for use as highly active nano-catalysts. The nano-porous structures were formed by self-assembled agglomeration of nanocrystallites without templates. Furthermore, the dendritic nano-porous manganese oxide as an electrocatalyst showed a significant decrease in overpotential on oxygen reduction in alkaline electrolyte.     

Synthesis and characterization of block copolymers by metal‐ and solvent‐free ring‐opening polymerization of cyclic carbonates initiated from PEG‐based surfactants

Ring‐opening polymerizations of trimethylene carbonate (TC) and 2,2‐dimethyltrimethylene carbonate (DTC) are initiated from hydroxyl‐terminated polyethylene glycol (PEG) and PEG‐based surfactants (Triton X‐100 or Triton X‐405) in the absence of any catalysts. The metal‐ and solvent‐free polymerizations proceed under melt at 150 °C, affording Triton X‐100‐block‐poly(TC) with M_n of 1400–5200 and Triton X‐100‐block‐poly(DTC) with M_n of 1800–7100 in excellent yields. The molecular weights and the comonomer composition of the resulting copolymers are controlled by the feed ratios of the monomers to the initiators, confirmed by gel permeation chromatography and ¹H NMR spectroscopy. The solubilities of the block copolymers composed of hydrophilic PEG segment and hydrophobic poly(TC) or poly(DTC) segment depend on both the compositions and the components. For example, Triton X‐100‐block‐poly (TC) (TC/EG = 9.5/9.5) and Triton X‐405‐block‐poly(TC) (TC/EG = 28/40, 46/40) milky suspend in water, while Triton X‐405‐block‐poly(TC) (TC/EG = 9.7/40) dissolves in water. A dynamic light scattering study reveals that the particle distribution of a copolymer, Triton X‐405‐block‐poly(TC) (TC/EG = 9.7/40) in water, has a monodisperse unimodal pattern ranging from 92 to 368 nm. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 1985–1996, 2006     

Classification of the binding modes in bovine serum albumin using terminally substituted alkane analogues.

With the fluorescence probe of 8-anilino-1-naphthalenesulfonate (ANS), the binding modes of terminally substituted alkane analogues (C(n)X; X = COOH, OH, CHO, NH(3), CONH(2)) to bovine serum albumin (BSA) were investigated using a competitive binding technique. The Scatchard plot of the fluorometric titration of BSA with ANS showed that the maximum binding number of ANS, n(max), was 3.81, with the binding constant, K(bnd), of 1.42 x 10(6) mol(-1) dm(3). The binding modes of C(n)X to BSA were analyzed based on the fluorometric titration of the ANS and BSA mixture with C(n)X. C(n)COOH completely displaced the ANS bound to BSA, whereas C(n)OH and C(n)CHO displaced only about 40% of the ANS bound to BSA. In contrast, C(n)NH(2) and C(n)CONH(2) displaced very little bound ANS. By comparing these results, we classified the binding modes of C(n)X to BSA into three types. Two of them are detectable with the ANS fluorescence and the remaining one is not detectable with the fluorescence.     

Bio‐reduction of Redox‐Sensitive Albumin Conjugates in FcRn‐Expressing Cells

Disulfide‐containing IgG‐, Fc‐, or albumin‐based prodrugs that rely on FcRn‐trafficking by endothelial cells for prolonged circulation in the body might be hampered by premature bio‐reduction processes during FcRn‐mediated recycling events. A detailed bio‐reduction analysis of redox‐sensitive albumin conjugates in two FcRn‐expressing cell lines has been performed. The obtained results indicate that the FcRn‐mediated recycling pathway is not (or is only poorly) bio‐reducing.     

Magnetoresistance in the magnetization reversal process of micropatterned Co wires

We measured the magnetoresistance (MR) and magnetization of Co wires of various widths in the range from 0.3 to 200 μm. The observed width dependence of some characteristics of MR is attributed to the change of the domain structure. As the width decreased below 1 μm, an abrupt jump appeared in the longitudinal MR. This can be interpreted as due to an abrupt reversal of the overall magnetization. The measured longitudinal MR was compared with the calculation in the Stoner–Wohlfarth model.     

Multi-nucleon transfer near the coulomb barrier induced by 32S and 34S

Neutron excess targets of ⁷⁶Ge, ^92,94,96Zr and ¹⁰⁰Mo have been bombarded with ³²S and ³⁴S at beam energies around the Coulomb barrier. Multi-nucleon transfer reactions involving 3p, 4p, 3pn, 4pn (projectile → target) and 3n, 4n, 6n (target → projectile) have been observed by measuring the corresponding back-scattered radioactive products like ²⁹Al, ²⁸Mg, ²⁸Al, ²⁷Mg, ³⁷S and ³⁸S. In some cases excitation functions and angular distributions have been measured.     

A study of the sintering effect on ultrafine silver particles by means of positron annihilation

Angular correlation curves of two-photon annihilation in ultrafine silver particles are shown to become similar to that of bulk silver with increasing degree of sintering.