Color appearance of afterimages compared to the chromatic adaptation to illumination

The color appearance of negative afterimages was measured by the elementary color naming method, and the results were compared with those obtained by the two‐room technique. Twenty adapting stimuli were presented on a display sequentially. Subjects first assessed the color appearance of the stimuli. After looking at the adapting stimulus for 10 seconds, the subjects assessed color of the afterimage. Apparent hue of the afterimage was in general not opponent color to the adapting color. The relation between the adapting stimuli and the afterimages was analyzed by the angle difference Δθ, when apparent hues are expressed by the angles of the points on the polar diagram of the opponent color theory. The relation relationship of Δθ to the angle of the adapting color θ_ing was quite similar to the results obtained by the two‐room technique, implying that the chromatic adaptation shown by the afterimage also occurs in the brain rather than in the retina.     

Clarification of differences between variable achromatic color and variable chromatic color methods in the Helmholtz–Kohlrausch effect

The Helmholtz–Kohlrausch effect consists of two different approaches: the variable achromatic color (VAC) and variable chromatic color (VCC) methods. In this article the difficult conceptual difference between the methods is clarified using new explanations with their schematic figures. The concept of loci with various parameters on B / L or L / Y ratios is completely different between the two methods. The VCC method can determine perceived lightness values for achromatic and chromatic colors in the whole color space. The VAC method gives perceived lightness deviation between reference achromatic color and each of the various test chromatic colors both kept at the same Munsell Value. The VAC method can never give any information on equiperceived lightness to test chromatic colors. Despite the difference between the two methods, misuse of the VAC method is sometimes found for perceived lightness studies of various chromatic colors, because of its ease in observations. An example is shown for the L scale of OSA‐UCS. © 2006 Wiley Periodicals, Inc. Col Res Appl, 31, 146–155, 2006     

A multi-scale analysis of the effect of complex viscoelastic models on Listeria dynamics and adaptation in co-culture systems

Natural antimicrobials are of interest to replace traditional food decontamination methods: they are milder and maintain desirable sensory characteristics. However, efficacy can be affected by food structure/composition, thus structural effects in a co-culture pathogen/microflora system are investigated. Listeria was grown planktonically (liquid broth) or on a biphasic viscoelastic system, in monoculture with/without artificial nisin, or in co-culture with Lactococcus lactis (nisin/non-nisin producing). Microbial growth kinetics were monitored and advanced microscopy techniques were utilized to quantify cellular interactions and spatial organization. Microstructural effects are observed on the kinetics, with differences in monoculture/co-culture. Significant microscopic differences are observed in spatial organization and colony size. We are the first to observe changing growth location for all species in monoculture/co-culture, with differences in colony size/organization through stationary phase. This study provides insight into the environmental stress response/adaptation of Listeria grown on structured systems in response to L. lactis and natural antimicrobials.     

动态热力学分析法评估短纤维/橡胶复合材料界面粘合效果

采用动态热力学分析法评估短纤维／橡胶复合材料（SFRC）界面层的粘合效果。其基本原理为；使用动态热力学分析仪测定SFRC的损耗因子（tanδ），依据公式计算出表征材料界面粘合强度的参数α。试验结果表明。α值越大，材料的界面粘合效果越好，SFRC的拉伸强度、撕裂强度和耐磨性能也越好，但拉断伸长率减小。该方法具有操作简单、数据精确和周期短等优点。     

The effect of localized electric fields on the detection of dissolved sulfur species from Type 304 stainless steel using scanning electrochemical microscopy

This paper discusses a method for imaging localized sulfur concentrations dissolved from sulfide inclusions in Type 304 stainless steels. The method involves amperometric detection using the I⁻/I₃⁻ redox couple as a mediator for sulfide oxidation. The microelectrode current for I⁻ oxidation is amplified by chemical reduction of I₃⁻ to I⁻ by dissolved thiosulfate and/or H₂S. While galvanostatically inducing corrosion, an unexpected current inversion at the microelectrode was observed at higher sample current densities in close proximity to the area where sulfur was detected at lower sample current. In the article first describing this method, J. Electrochem. Soc. 147 (2000) 4120 did not observe this feature. It was found that the inverted feature resulted from the localized increase in the electric field at the corrosion site, shifting the potential of the microelectrode when positioned over the site. The electric field measurement is analogous to measurements performed using a scanning vibrating electrode technique (SVET). This paper presents the first known combination of localized electric fields and chemical detection for determining localized electrochemical activity at a corroding surface.     

基于熵权和灰色关联分析的评判方法优选油气田增产措施

采用基于熵权和灰关联分析的多因素综合评判方法对油气田增产措施进行优选,以熵权代替灰色关联分析中的权重,克服了人为赋值的主观性。文中首先对油气田增产措施的评价指标进行了分析,然后建立了相应的多因素综合评判理论模型,最后结合具体实例对该评判方法进行了检验。结果表明:该方法是切实可行的,具有很高的应用价值。     

Evaluation of assisting methods on fluidization of hydrophilic nanoagglomerates by monitoring moisture in the gas phase

Agglomerates of nanoparticles were fluidized conventionally and under the influence of assisting methods such as vibration and/or moving magnetic particles. The adsorption/desorption rate of moisture of fluidized hydrophilic nanopowders was monitored during humidification/drying of the powder in order to find their adsorption isotherms at room temperature and to evaluate the assisting methods. Adsorption isotherms were verified by a gravimetric method. The nanopowders studied were Degussa Aerosil^® 200 and Aerosil^® 90, which were chosen because of their different fluidization behaviors.The moisture level in the nitrogen gas used to fluidize the powders was monitored on-line by using humidity sensors upstream and downstream of the fluidized bed. Moisture was added to the fluidizing nitrogen by bubbling it through water. The amount of moisture adsorbed/desorbed by the powders was obtained by integration of the time dependant moisture concentration. It was found that when the bed of powder is assisted during fluidization, the mass transfer between the gas and the nanopowder, as measured by the amount of moisture adsorbed/desorbed, is larger than when the powder is conventionally fluidized. Vibration assistance was found to be more effective for Aerosil^® 200, an APF type nanopowder, but magnetic assistance was needed for Aerosil^® 90 in order to break down the very large agglomerates formed in this ABF nanopowder.     

Buoyancy effect on the ultrafiltration of PEG 10,000. Visualization by digital holographic interferometry

Digital holographic interferometry has been used to visualize the buoyancy effects on dead‐end ultrafiltration of PEG 10,000. Sets of experiments have been carried out with the membrane in different orientations (90^°, 180^°), using a feed concentration of PEG 10,000 ranging 5–12.5 kg/m³. These results were compared with those obtained in previous research with the cell placed in its natural position (0^°). The interferometric fringe patterns obtained in this research were very different from those obtained previously. Whereas at the 0^° position, an increasing number of interferometric fringes appeared parallel to the membrane surface at 90 and 180^° positions, the number of interference fringes was much lesser and, with the 180^° orientation, slightly curved protuberances appeared after a short period of time that, like big drops, fell downward from the membrane surface. The consequence is a decrease of the polarization layer and an enhancement of the membrane performance. © 2012 American Institute of Chemical Engineers AIChE J, 2012     

Non-shrinkage porous ceramics by In-situ hollow sphere method based on the Kirkendall effect of Al particle

The significant shrinkage of porous ceramics after sintering has produced a number of issues with their use and development. As a result, we proposed an in-situ hollow sphere method for producing non-shrinkage alumina porous ceramics. The obtained green samples were made up of Al₂O₃ and Al powders, with pores emerging inside the materials due to the Kirkendall effect of Al particles after sintering. The expansion of hollowing particles exactly offsets the shrinkage generated by sintering throughout the process. When 50 vol. % Al powder (10 µm) is added, the linear shrinkage rate of the sample after sintering at 1500 °C can reach −3.47 %, and its apparent porosity and flexural strength are 30.69 % and 44.03 MPa, respectively. According to approximate calculations, the pores formed by the oxidation of Al powder are smaller than the initial size of Al powder. This method suggests a novel approach for producing controlled shrinkage porous ceramics.     

Molecular insight into the effect of ion structure and interface behavior on the ammonia absorption by ionic liquids

Molecular dynamics simulations were performed to elucidate the roles of ion structure and interface behavior in absorption of gases (NH₃, N₂, H₂) by ILs (protic IL [Bim][Tf₂N] and conventional IL [Bmim][Tf₂N]). The results indicated that NH₃ compete with [Tf₂N]⁻ to interact with N3-H site of [Bim]⁺ cation, forming a strong N3 H∙∙∙N(NH₃) hydrogen bond with the energy of −79 kJ/mol, which is twice as much as the energy of the hydrogen bond between C2 H of [Bmim]⁺ and NH₃ (−33.2 kJ/mol). Moreover, there is a dramatic increase in the number density of cations near the IL-gas interface, resulting in the NH₃ molecules permeate into the bulk rapidly and effectively and achieving the high selective absorption of NH₃ to H₂ and N₂. Considering the inevitable trace water in the raw gases, the influence of water was studied and it was shown that trace water can enhance the absorption of NH₃ by [Bim][Tf₂N].     

A systematic study of solvent effect on the crystal habit of dirithromycin solvates by computer simulation

The crystal habits of five dirithromycin solvates were employed to unravel the solvent effect by using the modified attachment energy (AE) model. Solvents with different polarity and hydrogen bond donor/acceptor ability (acetone, 1-propanol, acetonitrile, water and cyclohexane) were studied. The good consistency between experimental results and predictions confirmed the applicability of modified AE model. Simulation results showed that all solvates underwent a change in morphological importance (MI) of crystal faces except for the cyclohexane trisolvate. A detailed analysis of the results indicated that the polar solvent had a stronger interaction with crystal face than the non-polar solvent due to the formation of hydrogen bond. Furthermore, crystals with similar structure in different solvents exhibited different aspect ratios. The computer-aided study approach in this work could be helpful to control the morphology of crystal by tailor-made solvents or additives.     

光电激发与均相催化降解可溶性染料水的研究

将太阳光照与电解共同作用于含可溶性催化剂和染料的均相体系，在光、电的激发下，体系的反应活性大大提高，染料的降解大大加速并最终分解为水和二氧化碳等无机分子，降解过程没有沉淀产生，实现了有机污染的一次性快速处理。这种光、电、催化剂协同作用处理有机污染的方法，提高了降解速度，简化了处理过程，有效地利用了太阳能，节约了电能，降低了处理成本，有可能成为一种在工业上行之有效的一次性快速处理有机污水的方法。     

The effect of ageing step elimination on the memory effect presented by Mg0.75Al0.25 hydrotalcites (HT) and their catalytic activity for cyanoethylation reaction

The absence of ageing step in the coprecipitation method leads to modification of textural and structural properties of Mg_0.75Al_0.25 hydrotalcites which are reflected in the “memory effect” and in the catalytic activity of these samples for cyanoethylation reaction between ethanol and acrylonitrile where the beta-ethoxypropionitrile is the prevailing reaction product. The solids were characterised by XRD, DRIFT, TEM and base sites determination by adsorption of molecules with different pK_a aiming to establish a correlation between structural characteristics and the catalytic activity.     

The comparative effect of a mixed urea,ammonium nitrate,ammonium sulphate granular formulation on the efficiency of N recovery by perennial ryegrass

The¹⁵N isotope was used to study the mode of action of individual nitrogen sources in a 30% urea:30% ammonium nitrate: 10% ammonium sulphate:30% filler (w/w) granular fertilizer for perennial ryegrass in a greenhouse pot experiment. The fertilizer consisted of two types of granules, one containing 80% urea and 20% filler and the second containing 48% ammonium nitrate (AN), 16% ammonium sulphate (AS) and 36% filler. In addition the effect of dolomite compared with silica as the filler was investigated on nitrogen recovery from the 30:30:10:30 formulation.Dolomite adversely affected the recovery of nitrate N from the system and evidence suggested that MgCO₃ was the active component. Granules containing dolomite resulted in a lower dry-matter yield than those containing silica, however the difference was not significant as nitrate contributed only 20% of the N in the formulation. AN gave the greatest DM yield and urea the lowest with AS being intermediate. The¹⁵N budget in shoots, roots and soil indicated that only 65% of the N from urea was recovered at the end of the experiment compared with 86% for AN and 91% for AS. The dry-matter yield of the 30:30:10:30 formulation using silica as the filler was intermediate between urea and AN; however, the apparent N recovery was significantly higher than expected from the sum of the individual components. The use of¹⁵N labelling indicated that using separate granules for ammonium N and urea the recovery of urea was improved by 11% in the triple N mixture when both AN and AS were present in the second granule compared to the recovery on its own. The enhanced recovery of urea appeared to be a function of AN and AS acting together as neither source in double combination with urea had any effect on urea N recovery.Urea enhanced the recovery of nitrate N by 10% but decreased the recovery of AS by 6% (in the 30:30:10:30 formulation) in comparison with the single sources on their own. The results indicate that interactions can occur between N sources even when they are physically separated by being in different granules.     

A study of evolved gas control and its effect on carbon yield during the activation of carbon fibres by controlled rate methods

The rate of evolution of CO₂ or CO was used to control the low temperature activation of carbon fibres in O₂ mixtures via a feedback loop operated by a PC and in-house software. The CO₂ or CO concentration was monitored by a mass spectrometer and its level kept constant by varying the O₂ concentration using mass flow controllers. Experiments were carried out at the same evolution rates for identical times at temperatures of 500–800 °C. It was found that the rate of carbon burn off was not constant and varied with the temperature, especially where the rate of CO₂ evolution was controlled. The proposed reason for this was the high temperature gas phase oxidation of CO. However, surface areas of up to 1500 m² g⁻¹ were produced by these methods and thermal runaway was avoided.     

Anisotropy of the grain size effect on the electrical resistivity of n-type Bi1.9Gd0.1Te3 thermoelectric textured by spark plasma sintering

Spark plasma sintering (SPS) was applied to prepare textured Bi_1.9Gd_0.1Te₃ compounds with various grain structures, tuned by changing in the sintering temperature. The grains forming ordered lamellar structure under texturing are elongated in plane oriented perpendicularly to SPS-pressing direction. As result, average grain size measured parallel to this direction and corresponding to fine-grained samples happened to be much less as compared to relevant size for perpendicular direction characteristic for coarse-grained samples. Anisotropy in electrical resistivity inherent for single crystal was found to be partially recovered in textured samples, i.e. resistivity measured along directions parallel or perpendicular to SPS-pressuring direction is different. Moreover, resistivity for both directions is increasing with decreasing in grain size or with decreasing in intergrain distance. Grain size effect on resistivity due to grain boundary scattering of electrons was found to be anisotropic, since the effect is observed for different ranges of change in average grain sizes.     

The effect of pH on bioremediation potential for the removal of direct violet textile dye by Aspergillus niger

Alkaline and acidic media have been used in the textile dye industry, depending on the fabric nature. The bioremoval of textile direct violet dye by Aspergillus niger fungal strain was studied. The effect of pH on dye bioremoval was investigated at a pH range from 2 to 11. The direct violet dye bioremoval reached maximum with 92.4%, 64.0%, 91.4%, and 62.3 % at pH values of 2, 3, 8, and 9, respectively, at 24 h of incubation. The percentages of removal rate after 72 h incubation were 98.9, 97.3, 94.0, 95.0, 97.0, and 97.3 at pH 2, 3, 6, 7, 8, and 9, respectively. The optimum pH values were 2, 3, 8, and 9 for direct dye removal. At the end of the experiments, the treatment with fungal strain could reduce COD value of synthetic dye solution by 76-91%. Pseudo first and second order kinetic models were applied to evaluate differences in the biosorption rates and uptakes of textile dye. Pre-equilibrium biosorption of direct violet dye onto fungus under different dye concentrations followed a pseudo second order kinetic model with a high degree of correlation coefficients (R² > 0.99), and the calculated values of q_e nearly matched the experimental values of textile dye during the biotreatment process.     

Preparation of hairy particles by grafting PEG onto the poly(styrene‐co‐maleic anhydride) surface and PEG effect on SiO2 nanoparticles adsorption

Hairy particles were prepared by immobilization of poly(ethylene glycol) (PEG) on the surface of poly(styrene‐co‐maleic anhydride) (poly(S‐co‐MA)) spheres. It was found that the carbonyl groups on the poly(S‐co‐MA) surface can be conveniently esterified with the hydroxyl groups of PEG. Chemical and morphological changes were analyzed by FT‐IR, TEM, and water contact angle. Results revealed that, with the immobilization of PEG, the morphology of poly(S‐co‐MA) turned from a smooth surface to a hairy‐like structure and the hydrophilicity of the polymer particles improved. In addition, berry‐like polymer/silica particles can be obtained by using the hairy particles as template. The PEG hairy chains show steric repulsion during the deposition of silica nanoparticles by in situ sol‐gel process. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Plausible guard effect on the active sites of heterogeneous Ziegler–Natta catalyst by coordinating monomers and growing polymer chains in the initial stage of propene polymerization

Investigation of propene polymerization by a modified stopped‐flow technique using TiCl₄/ethylbenzoate(EB)/MgCl₂ Ziegler–Natta catalyst with or without pretreating the catalyst with triethylaluminium (TEA) within an ultra‐short period (ca 1 s) was conducted to gain new understanding of the nature of active sites related to TEA in the early stage of polymerization. When the catalyst was pretreated by a cocatalyst, deactivation behaviour was clearly observed, even within an extremely short pretreatment period. In contrast, without pretreatment, the deactivation of active sites can be neglected within the polymerization period indicating that the activated Ti species might be protected from deactivation by TEA when monomer is present in the system. A plausible guard effect on the active sites by coordinating monomer and growing polymer chains in the initial stage of polymerization is proposed to account for this phenomenon. Copyright © 2004 Society of Chemical Industry