Identification and determination of hexachlorocyclopentadienyl-dibromocyclooctane (HCDBCO) in residential indoor air and dust: a previously unreported halogenated flame retardant in the environment

Hexachlorocyclopentadienyl-dibromocyclooctane (HCDBCO, CAS 51936-55-1) has been detected in residential indoor air and indoor dust in Ottawa, Canada. The positive identification of the chemical was based on the interpretation of the mass spectra of the chemical obtained under both electron impact and negative chemical ionization operation modes, as well as through the synthesis of this chemical. This is the first report on the presence of HCDBCO in the environment. Although the levels of HCDBCO in indoor dust, with a geometric mean of 2.7 ng g(-1) and a median of 2.0 ng g(-1) respectively, are generally low compared to those of polybrominated diphenyl ethers (PBDEs) and dechlorane plus, another recently detected flame retardant, high levels of HCDBCO were detected in several dust samples with a maximum level of 93,000 ng g(-1) which is 16 times higher than the maximum level of the structurally related dechlorane plus. On the other hand, levels of HCDBCO in indoor air, with a geometric mean of 70 pg m(-3) and a median of 92 pg m(-3), were higher than those of the major PBDE congeners. The maximum level of HCDBCO found in indoor air was 3000 pg m(-3). Structurally, HCDBCO belongs to a group of norbornane based halogenated flame retardants. The presence of HCDBCO in the indoor environment may raise awareness of the potential release of this and related flame retardants into the environment during the production and usage of products that contain them, and the potential implications of human exposure to these chemicals as people spend the majority of their time indoors in modern society.     

Greenways, blueways, skyways and other ways to a better London

“ Landscape planners are quick to criticise other professions for single-use planning, but we tend towards the same mistake when planning greenways and urban greenspace.” This proposition is illustrated by the great series of open space plans which was prepared for London between 1929 and 1976. It is then discussed from a theoretical standpoint with reference to Christopher Alexander, the ‘pattern analysis’ approach to landscape planning, and the author's 1991 report to the London Planning Advisory Committee, Towards a Green Strategy for London. The paper concludes that ‘greenway’ is an excellent marketing term, but that product diversification and product differentiation must take place. We need special varieties of greenway for special purposes. Brief Alexander-type patterns are outlined for seven varieties: parkway, blueway, paveway, glazeway, skyway, ecoway and cycleway.     

Transmission Electron Microscopy-Based Analysis of Electrically Conductive Surface Defects in Large Area GaSb Homoepitaxial Diodes Grown Using Molecular Beam Epitaxy

We investigate a mechanism causing shorting of large area GaSb diodes grown on GaSb substrates using molecular beam epitaxy (MBE). The source of these shorts is determined to be large crystallographic defects on the surface of the diodes that are formed around droplets of gallium ejected from the gallium Knudsen cells during MBE. The gallium droplets cause defects in the crystal structure, and, as the epitaxy continues, the gallium is incorporated into the surrounding material. The shape of the defects is pyramidal with a central void extending from the epi-surface to the gallium core. Processing a GaSb diode with these surface defects results in the top-side contact metal migrating into the defect and shorting the diode. This prevents realization of large area diodes that are critical to applications such as photovoltaics and detectors. The diodes in this study are electrically characterized and the defect formation mechanism is investigated using cross-section transmission electron microscopy and electron dispersive spectroscopy.     

Socially-Aware Multimedia Dissemination in Personal Mobile Networks

Wireless Personal Communications - Mobile multimedia entertainment is pervasive on mobile devices, leading people to access, store and disseminate a diversity of multimedia contents anytime and...     

Rotation moment invariants for recognition of symmetric objects.

In this paper, a new set of moment invariants with respect to rotation, translation, and scaling suitable for recognition of objects having N-fold rotation symmetry are presented. Moment invariants described earlier cannot be used for this purpose because most moments of symmetric objects vanish. The invariants proposed here are based on complex moments. Their independence and completeness are proven theoretically and their performance is demonstrated by experiments.     

手持设备中的散热增强型功率MOSFET

安森美半导体最近推出的μCool功率MOSFET系列,结合其领先的沟道式FET技术与高效散热紧凑型WDFN6封装设计.本文将集中讨论μCool系列的散热性能,并就几种典型应用来谈论.     

Theorizing gender in the face of social change: Is there anything essential about essentialism?

The authors examine how beliefs about the stability of the social hierarchy moderate the link between sexism and essentialist beliefs about gender and how the expression of essentialist beliefs might reciprocally affect the social structure. Studies 1 (N = 240) and 2 (N = 143) presented gender-based inequality as stable, changing, or changed. In both studies, sexism was positively associated with essentialism only among men and only when inequality was presented as changing. Study 3 (N = 552) explored the possible consequences of expressing essentialist theories for social change. Exposure to essentialist theories increased both men's and women's acceptance of inequality. Exposure further increased men's support for discriminatory practices and boosted their self-esteem. These patterns demonstrate that although essentialism is linked to prejudice, this link is itself not essential. Rather, essentialism may be invoked strategically to protect higher status when this is threatened by change and may be successful in so doing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Creativity and domain specificity: The effect of task type on multiple indexes of creative problem-solving.

This study addresses the issue of domain specificity within creativity by understanding the characteristics of creative tasks and how participants react to the task. Participants (N = 187) were given 1 of 3 realistic everyday problems to solve. The problems differed in terms of complexity, involvement, and problem-based efficacy. Problem solutions were evaluated on several measures of creativity. Results indicate that creativity was influenced by the type of problem solved and the measure of creativity used to evaluate the solution. Furthermore, these results were obtained after controlling for the effect of ability. Results imply that not all real-world problems are equivalent and that researchers need to investigate how reactions to different problems and the creativity index used may influence conclusions regarding creative problem solving. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Electropolymerization of N-methylanthranilic acid and spectroelectrochemical characterization of the formed film

The electropolymerization of N-methylanthranilic acid (NMAA) is reported in this paper. The monomer is substituted both at ortho- and N-position and, to the best of our knowledge, it has not been previously electropolymerized. Electropolymerization of NMAA was done on glassy carbon and optically transparent (indium) tin oxide electrodes. The obtained films, which are probably of an oligomeric nature (oligoNMMA), were characterized with cyclic voltammetry (CV), in situ UV–vis and Raman spectroscopy, ex situ FTIR spectroscopy and scanning electron microscopy (SEM).Our results show that NMAA can be electropolymerized as thin films in 1.0 M HClO₄, but the oxidation and reduction peak currents in the CVs indicate that the formed oligoNMAA films are thinner than poly(N-methylaniline) or poly(N-butylaniline) films prepared under similar conditions. The CV and UV–vis measurements confirm that oligoNMAA have three oxidation states like suggested in the redox scheme of substituted polyanilines. The Raman spectra of oligoNMAA also verify that more quinoid units are formed at higher potentials in accordance with the redox scheme. The ex situ FTIR measurement proves that covalently attached carboxylic acid groups are present in the film structure and attached to the oligoNMAA backbone.