Effect of microstructure and fusion temperature on the electrical and optical properties of vanadate glasses

The electrical and optical properties of binary semiconducting oxide glasses containing 45 mol % V₂O₅ and 55 mol % GeO₂ fused and equilibrated at various temperatures (T ) in air were measured.T was varied over the range from 1000 to 1350° C. Their electrical and optical properties are shown to be sensitive to microstructure and melt temperature. We suggest that the change inT caused progressive microstructure changes of these glasses, which dramatically affected the electronic conductivity and the activation enthalpy for conduction.     

Spin glass behaviour in the Co2−xZnxTiO4 compound

A.c. susceptibility measurements were carried out on the disordered spinel system Co_2–x Zn _x TiO₄ (0<x<1) between 10 and 80 K. Our measurements show three peaks in the versus T curve for Co₂TiO₄ and CoZnTiO₄ compounds. In both compounds two peaks are very close to each other, indicating that the Néel and semi-spin glass temperatures are very close. A third peak indicates the presence of the semi-spin glass to spin glass transition. In Co_1.5Zn_0.5TiO₄ only one peak is observed which indicates spin glass ordering at 26 K. Furthermore, the A-site canting present in Co₂TiO₄ and CoZnTiO₄ has a collinear and magnetic structure, indicating strong A-B coupling. X-ray analysis indicated that compounds of the system Co₂Zn_xTiO₄ synthesized with cubic symmetry. From transport properties it was found that the activation energy and thermoelectric coefficient decrease with increasing concentration of Zn in the system. The mobility of the system calculated from infrared measurements is typically of the order of 10^–9cm²V^–1s^–1.     

A spectroscopic study of vanadium-phosphate glasses containing vanadium chloride

The optical properties of vanadium-phosphate glasses containing various amounts of (V₂O₅)₅₀(P₂O₅)_50–x (VCl₃) _x , wherex = 0.05, 0.06, 0.08 and 0.1, were measured as a function of VCl₃ content. It is found that by adding VCl₃ to the melt when the glass is formed, the added chlorine which acts as an oxidizing agent alters the ratio of concentration of vanadium ions and thus the absorption coefficient. Data on absorption in this study show that the power law,() =B() –E ₀) ⁿ / is best followed forn = 3, and the absorption is solely due to vanadium oxide. Furthermore, the infrared absorption spectra of this system were investigated in the wave number range 400 to 4600cm^–1. The addition of VCl₃ to the vanadium-phosphate glasses does not seem to introduce any new absorption band in this range as compared with the spectrum of a pure vanadium-phosphate glass. Furthermore, no significant difference in the absorption spectra was observed by annealing the V₂O₅-P₂O₅ glasses up to 200° C.     

Adhesion to skin

The failure energy of an adhesive bond can be factorized into two terms, one of which is a dimensionless loss function and the other, the true interfacial bonding energy, ₀. Experimental techniques have been developed to effect a separation of these two terms and thus measure ₀, but they are unsuitable for the pressure-sensitive adhesives used in surgical tapes and dressings. This is because these adhesives flow readily under load. This paper describes an extrapolation technique by which this problem can be resolved. Adhesive peel data are extrapolated both to zero peel velocity and zero load, to give a true threshold value for peeling energy which is independent of temperature. Values of ₀ are given for a natural-rubber based adhesive and substrates of glass and human skinin vivo. For glass ₀ = 28J m^–2 and for normal skin ₀ 14J m-2.     

钛合金叶片隔热烘漆的研制

以双酚A型环氧树脂为主要成膜物质,以氮化硼为功能填料,以丁醇醚化脲醛树脂为固化剂,并添加己二酸聚酯弹性体树脂改善其柔韧性、提高涂膜的机械性能,最终得到附着力强、耐热性好、隔热作用明显的飞机发动机叶片用防护涂料.     

Thermoelectric properties of SbNCa3 and BiNCa3 for thermoelectric devices and alternative energy applications

Thermoelectric properties of two antiperovskites SbNCa₃ and BiNCa₃ are calculated using first principles calculations. High values of Seebeck coefficients are observed for these materials. Electrical and thermal conductivities are also calculated. Increase in thermal conductivity and decrease in electrical conductivity are found with increasing temperature. The maximum values of thermal conductivity are 92×10¹⁴  W/m K s and 88×10¹⁴  W/m K s for SbNCa₃ and BiNCa₃ respectively at a temperature of 900 K. The peak values of 5×10²⁰/Ω m s and 5.2×10²⁰/Ω m s are achieved for n-type SbNCa₃ and BiNCa₃ respectively at a temperature of 300 K. Figure of merit is achieved for these materials at room temperature which shows that these materials can be useful for thermoelectric devices and alternative energy sources.     

Photochemical oxidation of fatty acid esters with and without chlorophyll

1. It has been confirmed that the principal products formed in the oxidation of methyl oleate by oxygen under a variety of conditions are predominantlytrans hydroperoxides. However no inversion of the double bond occurs in unoxidized oleate. Hence the conversion ofcis totrans double bonds and peroxide formation occur together in the same molecules.
2. The autoxidation of methyl linoleate at low temperature yields predominantlycis,trans conjugated hydroperoxides. Autoxidation at 25°C., oxidation catalyzed by visible light, or ultraviolet light and copper soap catalyzed oxidation at temperatures appreciably above 0°C., lead to the formation primarily oftrans,trans conjugated hydroperoxides. The inversion of the second double bond in this case appears to be independent of the peroxide-forming reactions.
3. The photochlorophyll oxidation of methyl linoleate leads to the formation of some unconjugated hydroperoxides, some of which containtrans double bonds.
4. Under all of the conditions employed in the present investigation, the oxidation of methyl oleate and linoleate led primarily to the formation of monomeric peroxides which retained most of the unsaturation of the parent compound.

     

Painting-91: a large scale database for computational painting categorization

Computer analysis of visual art, especially paintings, is an interesting cross-disciplinary research domain. Most of the research in the analysis of paintings involve medium to small range datasets with own specific settings. Interestingly, significant progress has been made in the field of object and scene recognition lately. A key factor in this success is the introduction and availability of benchmark datasets for evaluation. Surprisingly, such a benchmark setup is still missing in the area of computational painting categorization. In this work, we propose a novel large scale dataset of digital paintings. The dataset consists of paintings from 91 different painters. We further show three applications of our dataset namely: artist categorization, style classification and saliency detection. We investigate how local and global features popular in image classification perform for the tasks of artist and style categorization. For both categorization tasks, our experimental results suggest that combining multiple features significantly improves the final performance. We show that state-of-the-art computer vision methods can correctly classify 50 % of unseen paintings to its painter in a large dataset and correctly attribute its artistic style in over 60 % of the cases. Additionally, we explore the task of saliency detection on paintings and show experimental findings using state-of-the-art saliency estimation algorithms.     

Behavioral and physiological responses of cabbage looper,Trichoplusia ni (Hübner), to steam distillates from resistant versus susceptible soybean plants

Soybean plant volatiles, extracted as steam distillates, significantly affected the behavior and biology of the cabbage looper,Trichoplusia ni (Hübner) (Lepidoptera: Noctuidae). Distillates from the susceptible Davis variety attractedT. ni larvae and female adults, whereas those from resistant PI 227687 plants repelled them. When mixed in an artificial diet, steam distillates from PI 227687 plants caused mortality of first-instar larvae. Adults emerging from pupae topically treated with 5 g of such PI 227687 extractable showed developmental abnormalities. Larval feeding was significantly less on Davis leaves treated with PI 227687 volatiles as compared to solvent (acetone) or such Davis extractables. However, Davis volatiles on PI 227687 leaves did not increase larval feeding. HPLC analyses of steam distillates from susceptible Davis versus resistant PI 227687 indicated differences.     

Prediction of the viscosities of liquid mixtures by a group solution model

Group solution models of liquid mixtures have been used previously to predict thermodynamic properties of non-ideal systems. A model of this type has been developed which enables the viscosities of liquid mixtures to be predicted. The concept of an “ideal viscosity” is introduced, and allowance made for the interaction between the groups present and for the structural contributions of differing molecules. Predictions require a knowledge of only the viscosities of the pure components of a mixture. It has been tested for mixtures of alkanes, alcohols and water at 25°C, and gives good agreement with experiment. Experimental viscosities for ethanol/n-hexane, for n-propanol/water, and for four multi-component mixtures at 25°C are presented.