Complexation of samarium ion with poly(acrylic acid) grafted onto polyethylene by radiation-induced method

Acrylic acid was graft-polymerized onto polyethylene powder by preirradiation method. The grafted powder (PE-g-AA) rapidaly adsorbed Sm^3? ion in high efficiency. The poly(acrylic acid) grafted to the surface region of PE acted as an effective chelating site for the relatively large Sm ion. The complex formation constant of Sm ion with PE-g-AA was much larger than those of Sm ion with poly(acrylic acid) and propionic acid and of Cu²⁺ ion with PE-g-AA.     

Strength design criteria for steel members at elevated temperatures

Design equations for structural steel members at elevated (fire) temperatures are evaluated through comparisons with nonlinear finite element simulations. The study includes comparative analyses of the American Institute of Steel Construction (AISC) and European Committee for Standardization (CEN) design provisions for laterally unsupported I-shaped columns, beams, and beam-columns at temperatures between ambient to 800 ^°C. The Eurocode 3 provisions are shown to predict the simulated finite element results within about 10%-20%. On the other hand, the AISC specification predicts strengths that are up to twice as large (unconservative) as the simulated results. The discrepancies are largest for members of intermediate slenderness and temperatures above 300 ^°C. Modifications to the AISC equations are proposed that provide improved accuracy with calculated strengths typically within 20%-30% of the simulated results. Limitations of the member-based assessments and future research and development needs for structural fire engineering are discussed.     

Evidence and a computational explanation of cultural differences in facial expression recognition.

Facial expressions are crucial to human social communication, but the extent to which they are innate and universal versus learned and culture dependent is a subject of debate. Two studies explored the effect of culture and learning on facial expression understanding. In Experiment 1, Japanese and U.S. participants interpreted facial expressions of emotion. Each group was better than the other at classifying facial expressions posed by members of the same culture. In Experiment 2, this reciprocal in-group advantage was reproduced by a neurocomputational model trained in either a Japanese cultural context or an American cultural context. The model demonstrates how each of us, interacting with others in a particular cultural context, learns to recognize a culture-specific facial expression dialect. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Positive charge generation due to species of hydrogen during NBTI phenomenon in pMOSFETs with ultra-thin SiON gate dielectrics

Negative bias temperature instability (NBTI) of pMOSFETs with ultra-thin SiON gate dielectrics was investigated. We focused our attention on the behavior of hydrogen atoms released from the interface under NBT stress. From the transient characteristics of pMOSFETs after NBT stresses were stopped, it was found that a portion (60%, in our case) of hydrogen atoms released by the NBT stress remain in a 1.85-nm-thick NO-oxynitride gate dielectric. The existence of the hydrogen in the gate dielectric was shown to lead to the generation of positive charges.     

Total sputtering yields of solids under MeV-energy Si ion bombardment

Total sputtering yields have been measured for SiO₂ and Cu targets bombarded with Si ions at an incident energy between 500 keV and 5.0 MeV using a quartz crystal microbalance technique. In order to measure total yields accurately, we have developed a beam modulation technique to avoid the effect of thermal drift. In the MeV energy range, an ion penetrates through thin SiO₂ and Cu targets and is implanted into a quartz crystal. Therefore, the thickness of these layers deposited on quartz crystals was carefully controlled to avoid damage of quartz crystal by incident ions. As a result, total sputtering yields of SiO₂ increased with incident Si ion energy, while those of the Cu target decreased. The total yields of the SiO₂ target were represented well by a power low of the electronic stopping power.     

Spatial ordering of self-organized InGaAs/AlGaAs quantum disks on GaAs (311)B substrates

We report the control of self-organization of In_xGa_1−xAs/AlGaAs quantum disks on GaAs (311)B surfaces using a novel technique based upon lithography-defined SiN dot arrays. A strained InGaAs island array selectively grown using the SiN dots provides periodic strain field. When the pitch of lateral ordering corresponds with the period of the strain field, self-organized quantum disks stacked on the InGaAs islands are precisely arranged just as the buried SiN dot array. The spacing of the array element is 250–300 nm (x = 0.3) and around 150 nm (x = 0.4). Vertical alignment by strain is achieved at a very thick (95 nm) separating layer. Characterization using atomic force microscopy reveals the size-fluctuation of disk is dramatically improved with spatial ordering.     

纺丝及纤维成形的机理(Ⅵ)

本文依据前报阐述的数学模拟法的基础方程式和解析方法,系统地讨论了在不同泵供量和纺丝速度的情况下,沿纺丝线的丝条温度和固化点的变化,以及沿纺丝线聚合物的纵向运动速度梯度、纤维的细化过程、纺丝张力和纺丝应力的分布,并对与以上有关的主要参数进行了列表归纳。     

Solution‐processed organic TFT array for active‐matrix LCDs on a plastic substrate

Abstract— Organic TFTs (OTFTs) have been developed with a novel solution‐processed gate insulator of poly(4‐vinylphenol) (PVP) with the addition of octadecyltrichloro‐silane (OTS) and a solution‐processed organo‐silver electrode/wire to improve the performance of an OTFT and to maked high‐throughput‐manufacturing process possible. Solution‐processed PVP has also employed for a buffer layer on a plastic substrate. The OTFT backplane with these solution‐based organic‐material technologies has been successfully applied to drive a 2.5‐in. QQVGA (160 × 120 pixels) AMLCD with a resolution of 79 dpi.     

Competitive binding of divalent cations to poly(α-hydroxyacrylic acid)

The competitive binding of divalent cations (Mg²⁺, Ca²⁺, Mn²⁺, Co²⁺, Ni²⁺, Cu²⁺ and Zn²⁺) on poly(α-hydroxyacrylic acid) (PHA) and poly(acrylic acid) (PAA) was investigated by equilibrium dialysis. In the Mg/Ca mixed system, binding selectivity for Ca²⁺ over Mg²⁺ was significantly higher in PHA than in PAA; this was attributed to coordination of α-OH groups on PHA to Ca²⁺. The binding ability and selectivity for the transition metal cations were almost the same for PHA and PAA at neutral pH, while PHA maintained appreciably higher degrees of binding than PAA in acidic solutions (pH about 3). This cation binding ability of PHA was ascribed to the lower pK_a value in the relevant pH region. © 1998 SCI.     

Studies on the Dehydrogenative Polymerizations of Monolignol β‐Glycosides. Part 1. Syntheses of Monolignol β‐glycosides, (E)‐Isoconiferin, (E)‐Isosyringin,and (E)‐Triandrin

Abstract

(E)‐4‐O‐Acetyl coniferyl alcohol was synthesized by the reduction of (E)‐4‐O‐acetyl ferulic acid with sodium borohydride and N,N‐dimethylchloromethylenium chloride in 80.2% yield. The glycosylation of (E)‐4‐O‐acetyl coniferyl alcohol with trichloroacetimidoyl 2,3,4,6‐tetra‐O‐pivaloyl‐α‐D‐glucopyranoside in the presence of BF₃-Et₂O in anhydrous CH₂Cl₂, followed by deacylation gave (E)‐isoconiferin in high yield. This synthetic method could be applied to the syntheses of other monolignol β‐glycosides. As a result, (E)‐isoconiferin, (E)‐isosyringin, and (E)‐triandrin were synthesized from vanillin, syringaldehyde, and p‐hydroxybenzaldehyde, respectively, by five reaction steps in high overall yield.