Silica aerogel–poly(ethylene‐co‐vinyl acetate) composite for transparent heat retention films

Poly(ethylene‐co‐vinyl acetate) (EVA) plastic films are widely used for solar coverings including photovoltaic modules and commercial greenhouse films, but are poor at controlling heat flow. In this work, silica aerogel (SA) nanogels were examined for preparing transparent heat retention EVA films that block far infrared spectra radiation to maintain heat, without compromising the optical performance of the films. SA nanogels were melt‐mixed using a mini twin‐screw extruder with EVA pellets to form SA/EVA composite, which were pressed into thin films with controlled thickness. The composite films were characterized in terms of optical properties using a variety of analytical methods including FTIR, UV–Vis spectroscopy, electron, confocal, and atomic force microscopy. Both thermicity and thermal conductivity of commercial and experimental SA/EVA films were measured. The results demonstrated that the SA/EVA films gave improved infrared retention compared to commercial thermal plastic films without compromising visible light transmission, showing the potential for this approach in next generation heat retention films. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2014 , 52, 927–935     

Study of reduction processes over cerium oxide surfaces with atomic hydrogen using ultra accelerated quantum chemical molecular dynamics

Ceria plays an important role in catalysis, due to its ability to store and release oxygen depending on the condition present in the catalyst environment. To analyze the role of ceria in catalytic reactions, it is necessary to know the details of the interaction of ceria surface with environmentally sensitive molecules. This study was conducted using ultra accelerated quantum chemical molecular dynamics. Its purpose was to investigate the reduction process of the (1 1 1) and (1 1 0) surfaces of ceria with atomic hydrogen as well as water desorption mechanisms from the surfaces. This simulation demonstrated that when a high-energy colliding hydrogen atoms are adsorbed on the ceria, it pulls up an O atom from the ceria surfaces and results in the formation of a H₂O molecule. This is the first dynamics simulation related to such reduction processes based on quantum chemistry.     

Amphiphilic liquid‐crystalline 4‐miktoarm star copolymers with a siloxane junction leading to cylindrically nanostructured templates for a siloxane‐based nanodot array

Well‐defined A₃B‐, A₂B₂‐, and AB₃‐type 4‐miktoarm star copolymers (M_n = 10,500–16,200, M_w/M_n = 1.16–1.18) consisting of poly(ethylene oxide) (PEO) and polymethacrylate bearing an azobenzene mesogen (PMA(Az)) as the arms and cyclotetrasiloxane as the core unit were synthesized using a combined route composed of a thiol‐ene click reaction and atom transfer radical polymerization. Microphase‐separated structures of the star copolymers in thin films with a thickness of approximately 100 nm were investigated by GISAXS and TEM. The A₃B‐type star‐(PEO)₃[PMA(Az)]₁ copolymer formed a more highly ordered PEO cylinder array with perpendicular alignment in the PMA(Az) matrix than that of the corresponding linear‐type block copolymer. The center‐to‐center distance of the PEO cylinders and the cylinder diameter were 13 and 4 nm, respectively. The highly ordered star‐(PEO)₃[PMA(Az)]₁ thin film was directly transferred to a siloxane‐based nanodot array by oxygen reactive ion etching. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 1175–1188     

One-step SFE-plus-C(18) selective extraction of low-polarity compounds,with lipid removal,from smoked fish and bovine milk

Co-extraction of lipid materials is the major source of interference in determinations of low-polarity compounds in many biological matrixes. "SFE-plus-C(18)", a recently developed supercritical fluid extraction method employing C(18) adsorbent in the extraction chamber, can enable selective extraction of low-polarity compounds in lipid-rich biological matrixes without a cleanup step. This study reports the application of the SFE-plus-C(18) method to the quantification of: 1. polycyclic aromatic hydrocarbons (PAH) in commercially purchased smoked fish; and 2. anti-cancer agents cyclophosphamide (CP) and suberoylanilide hydroxamic acid (SAHA) spiked into homogenized whole bovine milk.Over the course of SFE-plus-C(18)extraction, indigenous lipids are preferentially retained on the C(18) adsorbent. Compared with the conventional method, only 8-15% of the lipids in the smoked fish sample, and only 6-18% of the lipids in the milk sample, were co-extracted by SFE-plus-C(18). This reduction in the quantity of background lipids significantly improved chromatographic separations, retarded deterioration of the column, and dramatically improved the ability to quantify PAH present at trace levels in smoked fish by GC-MS. Using the SFE-plus-C(18) method, ten targeted PAH were detected in the range 9.5-13.5 ng g(-1) in the smoked fish sample. Compared with these levels, PAH extractions by use of conventional SFE gave values that were lower by 38-86%. Recoveries of CP and SAHA spiked into milk were close to 100% in both SFE-plus-C(18)and conventional SFE, where the lipid background during the chromatographic elution of CP and SAHA was not so severe.     

Nonparametric estimation of location parameter after a preliminary test on regression in the multivariate case

For a simple multivariate regression model, nonparametric estimation of the (vector of) intercept following a preliminary test on the regression vector is considered. Along with the asymptotic distribution of these estimators, their asymptotic bias and dispersion matrices are studied and allied efficiency results are presented.     

Observation of the effects of radially sheared electric fields on the suppression of turbulent vortex structures and the associated transverse loss in GAMMA 10

Vortexlike turbulent structures in hot-ion mode plasmas with several keV are observed in the case with a radially produced weak shear of electric fields E(r). However, a strong E(r) shear formation due to a high ion-confining potential phi(c) production clears up these vortices together with plasma-confinement improvement and disappearance of both drift-wave and turbulencelike Fourier spectral signals. These findings are based on three-time progress in phi(c) in comparison to phi(c) attained 1992-2002. The significant advance of phi(c) is well extended in line with proposed potential-formation physics scalings.     

Simultaneous observation of low temperature 4f-4f and 3d-3d emission spectra in a series of Cr(III)(ox)Ln(III) assembly

We report here the low temperature emission spectra in the heterometal dinuclear 3d-4f assembled molecular system [(acac)₂Cr^III(μ-ox)Ln^III(HBpz₃)₂] (Cr(ox)Ln:acac⁻=acetylacetonate, ox²⁻=oxalate, HBpz₃⁻=hydrotris(pyrazol-1-yl)borate; Ln=La, Nd, Ho, Er , Tm and Yb) in comparison with those of Na[Cr(acac)₂(ox)] and [(HBpz₃)₂Ln(μ-ox)Ln(HBpz₃)₂](Ln=Nd and Er). From 10 to 150 K the Cr(ox)Ln complexes show a broad emission band around 800 nm from the ²E state of Cr(III) moiety. At room temperature no ²E-⁴A₂ emission was observed in the Cr(ox)Ln except for the La and Lu complexes. On warming from 10 to 300 K rapid quenching of the ²E-⁴A₂ emission of Cr(III) is suggested to result from the energy transfer from Cr to Ln in the Cr(ox)Ln. The excitation spectra and the life-time were also measured with monitoring the 4f-4f emission peaks of the Cr(ox)Yb complex.