Improvement of n-type OTFT electrical stability by gold electrode modification

N-type organic thin film transistors (OTFT) containing modified gold electrodes have been fabricated to investigate the influence of the self assembled monolayer on the transistor characteristics. We report on the effect of drain/source modification by thiol derivatives on the performances, electrical parameters uniformity and electrical stability of C₆₀ transistors. In the literature, electrical instability is often attributed to organic semiconductor (OSC), OSC-insulator interface and insulator. We found here that OSC-metal interfaces affect dramatically the operational stability for bottom gate/bottom contact structure. These effects have been attributed to morphological evolution at the interface metal-OSC induced by the self-assembled monolayers.     

Measuring magnetic anisotropy with a rotatable ac electromagnet

Magnetic anisotropy of magnetic thin films was determined from a series of hysteresis loops measured via a rotatable alternate current (ac) electromagnet, the rotation angle of which could be continuously tuned at 360° with a high resolution. Co₂FeAl Heusler alloy films grown by molecular beam epitaxy were used to show the benefits of the method for measuring magnetic anisotropy.     

Self-assembled silver nanoislands formed on glass surface via out-diffusion for multiple usages in SERS applications

We demonstrate that silver nanoisland film self-assembled on the surface of silver-containing glass in the course of thermal processing in hydrogen is capable to detect 10⁻⁷ M concentration of rhodamine 6G in water using surface enhanced Raman spectroscopy (SERS) technique. The film can be multiply restored on the same glass substrate via annealing of the glass in hydrogen. We showed that the film can be self-assembled after as much as ten circles of the substrate cleaning followed by annealing. The proposed technique of the silver nanoisland film formation enables multiple usage of the same glass substrate in SERS experiments.     

The Effect of Drying Temperature on Physical Properties of Thin Gelatin Films

The molecular morphology of thin gelatin films, controlled through the casting temperature, was monitored by wide angle X-ray diffraction (WAXD) and differential scanning calorimetry (DSC). Gelatin films dried at lower temperatures had a markedly higher crystalline or helical structure with a slightly higher T_g and lower ΔC_p compared with hot dried films, which had a more coiled structure. The relationship between molecular morphology and gelatin-water interaction in terms of hydration behavior and water diffusivity was assessed using dynamic vapor sorption (DVS). The sorption capacity increased and the level of hysteresis decreased with increasing the degree of crystallinity. The difference in the aging behavior of the films was explained in terms of the difference between the glass transition and aging temperatures, (Tg – Ta).     

High-temperature ferromagnetism of Ni-doped PbPdO2 nanograin films synthesized by sol-gel spin-coating method

The single-phase Ni-doped PbPdO₂ films with a body-centered orthorhombic structure were synthesized by the sol-gel spin-coating method and an oxidation treatment. The films with a thickness of about 440 nm were found to have a nanograin structure and large amount of Pb vacancies. The valence states of Ni and Pd ions within the Ni-doped PbPdO₂ films were very close to 2+, while the Pb ions exhibited a mixed valence between 2+ and 4+. The existence of Pb vacancies and the low electronegativity of Pb²⁺ ion resulted in the increase of the valence of Pb ions. The analysis of the magnetic properties indicated that the magnetisms of the single-phase Ni-doped PbPdO₂ nanograin films were all composed of the ferromagnetism and the paramagnetism. The ferromagnetism enhanced with the calcination temperature increasing and could be retained up to 380 K. A carrier-mediated mechanism bridged to the bound magnetic polaron model based on the Pb vacancies, the doped Ni ions and the Pb ions with a valence higher than 2+ were used to explain the magnetic origin of these Ni-doped PbPdO₂ nanograin films.     

捣固焦炉装入煤水分的检测、调节与控制

针对攀钢钒煤化工厂焦炉用煤特点和捣固配合煤水分要求,采用煤调湿工艺并安装微波在线测水和加水控制装置,保证捣固炼焦配合煤水分波动在1%以内,稳定装入煤水分,为生产顺行提供保障。     

Fine limestone additions to regulate setting in high volume fly ash mixtures

High volume fly ash (HVFA) concrete mixtures are being considered more frequently due to their cost and sustainability advantages. While the long term performance of these HVFA concretes typically meets or exceeds that of conventional concretes, their early age performance is often characterized by excessive retardation of the hydration reactions, delayed setting times, and low strengths. Extending an HVFA mixture to a ternary blend that incorporates a fine limestone powder may provide a viable solution to these deficiencies, particularly the hydration retardation and setting issues. In this paper, a nano-limestone powder and two other limestone fillers of increasing median particle size (4.4 μm and 16.4 μm) are investigated for their propensity to accelerate early age reactions and reduce setting times in a Class C fly ash/cement blend. The fineness of the limestone has measurable effects on its efficacy in accelerating hydration and decreasing setting times. Companion specimens prepared with a fine silica powder suggest that the fine limestone may act favorably through both a physical and a chemical mechanism. Isothermal calorimetry and Vicat needle penetration measurements on pastes are accompanied by strength measurements on mortars, to verify that the limestone powder substitutions are not negatively impacting strength development. A linear relationship with a reasonable correlation is found to exist between 1 d and 7 d compressive strengths of mortars and their accompanying cumulative heat release values as determined using isothermal calorimetry.     

米糠固脂与棕榈硬脂混合应用于起酥油的研究

米糠固脂是米糠油冬化或分提获得的副产物。以3种具有不同固体脂肪含量(SFC)曲线的米糠固脂(RBS1、RBS2及RBS3)、棕榈硬脂(PS)为原料,按照米糠固脂与棕榈硬脂质量比40∶60进行二元混合制备起酥油,并以市售起酥油为参考,对混合体系的SFC、晶型、脂肪酸组成、微量营养素含量进行了分析。结果表明:由不同米糠固脂组成的二元混合体系差异不大,且与市售起酥油具有相似的SFC曲线;其棕榈酸、亚油酸含量较市售起酥油高,硬脂酸含量较市售起酥油低;体系表现为β'晶型;此外,二元混合体系中含有丰富的谷维素、植物甾醇,可丰富起酥油的营养特性。     

Absorption and reflection of infrared radiation by polymers in fire‐like environments

In large‐scale fires, the input of energy to burning materials occurs predominantly by radiative transfer. The in‐depth (rather than just surface) absorption of radiant energy by a polymer influences its ignition time and burning rate. The present investigation examines two methods for obtaining the absorption coefficient of polymers for infrared radiation from high‐temperature sources: a broadband method and a spectral method. Data on the total average broadband transmittance for 11 thermoplastics are presented (as are reflectance data), and the absorption coefficient is found to vary with thickness. Implications for modeling of mass loss experiments are discussed. Copyright © 2011 John Wiley & Sons, Ltd.     

防水透气膜水蒸气透过性能和不透水性在应对建筑结露问题的功用及性能测试

为合理把握防水透气膜的防水和透气性能,从结露现象的本质入手分析了防水透气膜在应对建筑结露问题的作用机制,并从试验测试和生产工艺的角度提出了防水透气膜的性能控制要点。