Liquid crystal alignment properties of n-alkylsulphonylmethyl-substituted polyoxyethylenes

The liquid crystal (LC) alignment properties of LC cells fabricated with films of n-alkylsulphonylmethyl-substituted polyoxyethylenes (#S-PEO, #?=?4, 6, 7, 8 and 10), where # is the number of carbon atoms in the n-alkyl side groups having different n-alkyl chain length, were investigated as a function of the rubbing density. The LC cells made from unrubbed #S-PEO (# ≥8) films having more than eight carbon atoms in the n-alkyl side groups showed homeotropic LC alignment. The homeotropic LC alignment behaviour correlated well with the surface energy values of the unrubbed #S-PEO films; homeotropic LC alignment was observed when the surface energy values of the unrubbed #S-PEO films were smaller than about 21.62 mJ m^?2. The LC cells made from rubbed #S-PEO (# ≥7) films having more than seven carbon atoms with a rubbing density of 150 showed homeotropic LC alignment. It was also found that the tilt angle of the LCs on the rubbed #S-PEO films was affected not only by the n-alkyl chain length of the polymers, but also by the rubbing density, regardless of the surface energy value of the #S-PEO film.     

Plasma synthesis of nanosized W–Co composite powder followed by carburization with a methane–hydrogen mixture

Nanosized tungsten carbide and cobalt composite powder was synthesized by a two-step reaction via a thermal plasma process. Ammonium paratungstate (APT) and cobalt oxide were used as the precursors. The injected precursors were vaporized in the plasma flame and the subsequent reduction of the vaporized precursors produced uniformly mixed nanosized tungsten and cobalt composite powder. The subsequent carburization of this powder by CH₄–H₂ mixture resulted in the formation of nanosized WC–Co composite powder with a particle size <110 nm. This new method represents an alternative route that avoids the post-treatment required for the WC_1?x produced when methane was used for direct carburization in the powder production step.     

Some Theorems on the Rogers-Ramanujan Continued Fraction in Ramanujan's Lost Notebook

In his first two letters to G. H. Hardy and in his notebooks, Ramanujan recorded many theorems about the Rogers-Ramanujan continued fraction. In his lost notebook, he offered several further assertions. The purpose of this paper is to provide proofs for many of the claims about the Rogers-Ramanujan and generalized Rogers-Ramanujan continued fractions found in the lost notebook. These theorems involve, among other things, modular equations, transformations, zeros, and class invariants.     

Stress test for a technology credit guarantee fund based on survival analysis

A technology credit guarantee policy has been established to provide financial support to technology-based SMEs with a limited asset base. For an effective technology credit guarantee policy, risk management is essential. In this paper, we investigate a survival model that predicts start-up SMEs’ loan default probability at a given time based on technology attributes along with the economic environment and the firm’s characteristics at the time of the technology credit guarantee fund application. This, in turn, is used for the estimation of the technology fund risk along with a stress test. Our work is expected to contribute to reducing the risks associated with technology financing.     

Enhancement of cyclability using recombination reaction of Cu for Sn2Fe nanocomposite anode for lithium-ion batteries

A Sn₂Fe/C nanocomposite containing Cu was evaluated as an anode material for rechargeable lithium-ion batteries. The electrochemical reaction mechanism of this nanocomposite was examined by ex-situ X-ray diffraction and high resolution transmission electron microscopy. The Sn₂Fe/C nanocomposite containing Cu showed dramatically improved cycling performance. The enhanced cyclability of the Sn₂Fe/C nanocomposite containing Cu was attributed to both amorphization of the Sn₂Fe phase and a recombination reaction between Sn and Cu during the charging step.     

Chemical analysis of argon–oxygen decarburization slags in stainless steelmaking process by X‐ray fluorescence spectrometry

A quantitative analysis method of fluorine in the slags produced in the stainless argon–oxygen decarburization (AOD) process by X‐ray spectrometry was proposed employing direct analysis technique by pressed pellet. This research investigated the separate quantification of calcium fluoride and calcium oxide contained in AOD slags. X‐ray diffraction measurement was performed to identify the stable phase of fluorine compound, which is primarily present in the slags. The synthetic standards prepared in laboratory were used to construct the X‐ray fluorescence (XRF) calibration curves for F, Ca_tO, SiO₂, MgO, Al₂O₃ and Cr₂O₃, considering the matrix effects and line overlap corrections (t: total). The calibration curves were tested by the quantitative analysis of synthetic standards with satisfactory precision and accuracy. The proposed method might be an alternative solution to the problem with the simple and routine chemical analyses of calcium fluoride in AOD slags of stainless steelmaking process by XRF spectrometry. Copyright © 2010 John Wiley & Sons, Ltd.     

Selective addition of CXCR3+CCR4-CD4+ Th1 cells enhances generation of cytotoxic T cells by dendritic cells in vitro

Increasing importance is being given to the stimulation of Th1 response in cancer immunotherapy because its presence can shift the direction of adaptive immune responses toward protective immunity. Based on chemokine receptor expression, CXCR3⁺CCR4^-CD4⁺ T cells as Th1-type cells were investigated its capacity in monocyte-derived dendritic cell (DC) maturation and polarization, and induction of antigen specific cytotoxic T lymphocytes (CTL) in vitro. The levels of IL-4, IL-5 and IL-10 were decreased to the basal level compared with high production of IFN-γ, TNF-α, and IL-2 in CXCR3⁺CCR4^-CD4⁺ T cells stimulated with anti-CD3 and anti-CD28 antibodies. Co-incubation of activated CD4⁺ or CXCR3⁺CCR4^-CD4⁺ T cells with DC (CD4⁺/DC or CXCR3⁺CD4⁺/DC, respectively) particularly up-regulated IL-12 and CD80 expression compared with DC matured with TNF-α and LPS (mDC). Although there was no significant difference between the effects of the CXCR3⁺CCR4^-CD4⁺ and CD4⁺ T cells on DC phenotype expression, CXCR3⁺CD4⁺/DC in CTL culture were able to expand number of CD8⁺ T cells and increased frequencies of IFN-γ secreting cells and overall cytolytic activity against tumor antigen WT-1. These results demonstrated that the selective addition of CXCR3⁺CCR4^-CD4⁺ T cells to CTL cultures could enhance the induction of CTLs by DC in vitro, and implicated on a novel strategy for adoptive T cell therapy.     

Lithia formation mechanism in tin oxide anodes for lithium–ion rechargeable batteries

The lithia formation mechanism in tin oxide anode is investigated using electrochemical measurements and Auger spectroscopy. Based on the charge/discharge capacities for SnO electrode, the atomic ratio of Li to O in lithia is less than 2 at the discharge capacity of 400 mAh/g (～0.9 V). The derivative capacity plots show that the irreversible reaction occurs throughout the entire discharge to 0 V, and the atomic ratio of Li to O is about 1 at ～0.8 V and 2 at 0 V. Auger spectroscopy analysis also confirms that the atomic ratio of Li to O approaches to 2 only when discharged to 0 V. Thus, Li₂O appears to have formed at 0 V in the first discharge, not ～0.8 V as reported previously, such that the initial lithia composition is more like Li₂O₂.