Microstructure of (Fe0.2Co0.8)0.8(Fe2.38Co0.62O4): A Magnetic Oxidation Resistant Composite Formed by Coprecipitation

The metal–ferrite composite (Fe_0.2Co_0.8)_0.8(Fe_2.38Co_0.62O₄) has been studied by X-ray diffractometry measurements and high-resolution transmission electron microscopy. Spinel ferrite occurs in highly crystalline domains 100–150 nm in size, and the iron–cobalt alloy occurs in smaller and less-crystalline domains (10–20 nm). Both phases are heterogeneous in composition. The metal is embedded in the spinel phase, located near the edges, and overlaid by a poorly crystallized layer or misshapen regions containing small spinel crystals and amorphous phases. By annealing under vacuum up to 800°C, the misshapen regions disappear and the size of the metallic regions increases. The concentration of iron in the metallic regions decreases and their structure changes to face-centered cubic, while the spinel becomes enriched in iron.     

Boys don't write romance: the construcion of knowledge and social gender identities in english classrooms

Teachers have been under pressure in the United Kingdom to devise pedagogic strategies to raise boys' achievement. This article reviews the emergence of the concept of a 'setting' from within the sociocultural literature as the basis for considering the interaction between gender and learning. The second section reports findings from an empirical study of two teachers in one school who taught the same creative writing activity to their classes. The strategies in each classroom to improve boys' achievement in English varied, and involved mixed, gendered seating and single sex grouping. The strategies had unintended effects in terms of how subject knowledge was realised, and therefore what was available to learn and by whom. To demonstrate and explain these effects we illustrate how hegemonic representations of gender were reconstructed in each setting and present individual cases to illustrate students' experience of the settings. How settings mediate the interrelation between gender and learning at the interpersonal plane of analysis are discussed, and the reconstruction of knowledge and social gender identities at the personal plane.     

Evolution of the Pore Size Distribution in Final-Stage Sintering of Alumina Measured by Small-Angle X-ray Scattering

Small-angle X-ray scattering was used to follow the evolution of the pore size distribution during final-stage sintering of alumina and of alumina doped with 0.25 wt% magnesia. The volume-weighted (Guinier) results indicate that the effective size of the largest pores increases as the body goes from 97% to more than 99% dense. The surface-area-weighted (Porod) results show that the median size of the smallest pores decreases slightly over the same density range. Taken together, these data indicate that the pore size distribution becomes broader as final-stage densification proceeds. This was confirmed by a maximum entropy analysis, which was used to derive pore size distributions directly from the data. Finally, the evolution of the pore size distributions in alumina, with and without sintering aid, were compared.     

Measurement and Modelling of NO Fluxes on Maize and Wheat Crops During their Growing Seasons: Effect of Crop Management

Fertilized agricultural soils are a significant source of NO, a gas involved in tropospheric ozone formation. The aims of the research reported here were to measure NO fluxes over the length of the growing season of wheat and maize crops, and to build a model of soil NO emissions from arable land. Field experiments were carried out on a 1-ha field divided into two parts. The first one was cropped with wheat and harvested in late July, 2002, whereas the second part was sown with maize and harvested in October. The wheat and maize received 130 kg N ha⁻¹ and 140 kg N ha⁻¹, respectively. For each crop, NO fluxes were measured during 10 months every 2 weeks using manual closed chambers, and continuously with a wind tunnel immediately after nitrogen fertilization. Fertilizer application significantly affected NO emissions: the largest NO emissions were recorded a few days after nitrogen application. This delay depended on the kinetics of nitrogen incorporation in the soil, as influenced by rainfall. The emissions measured on the maize field (2.6% of the fertilizer amount applied) were more important than those on the wheat field (1.0% of the fertilizer amount applied), owing to differences in timing of nitrogen application, with respect to climate and crop growth. Relationships between soil nitrification rate and NO emission obtained from laboratory incubations, and experimental data appeared useful and relevant to predict NO emissions at the field-scale.     

Site‐specific Protein Cross‐Linking with Genetically Incorporated 3,4‐Dihydroxy‐L‐Phenylalanine

Come together right now with L ‐DOPA : Chemical cross‐linking is widely used to study protein–protein interactions. However, many cross‐linking agents suffer from low reactivity or selectivity. An efficient and selective reaction of site‐specific protein cross‐linking was achieved using genetically incorporated 3,4‐dihydroxy‐L ‐phenylalanine.

     

A Novel Flexible Hybrid Battery–Supercapacitor Based on a Self‐Assembled Vanadium‐Graphene Hydrogel

A novel flexible hybrid battery–supercapacitor device is proposed consisting of high specific surface area electrodes paired with an electrolyte, which contains a redox species that can exist in more than two oxidation states. The two initially equal half‐cells of the device consist of a reduced graphene oxide hydrogel which encapsulates vanadium ions, synthesized with a single‐step method. During charge, the oxidation state of the vanadium ions changes, resulting in two half‐cells with different potentials which considerably increases the energy density. The achieved maximum capacity of more than 225 mAh g^?1 is roughly eight times higher than that of comparable graphene hydrogel supercapacitors without vanadium content, but the potentiostatic charging time is only double. Operated as a supercapacitor, it retains 95% of the initial capacitance over 1000 cycles. As battery, the losses are more significant, retaining around 50% of the initial capacity. However, these losses during battery operation can be almost entirely restored by electric measures. The vanadium ion addition also improves the self‐discharge characteristics of the device. Moreover, the self‐discharge does not permanently damage the hybrid device since both half‐cells initially consist of the same vanadium graphene hydrogel and discharging resets it to initial conditions.     

Pore Sizes and Filtration Rates from Two Alumina Slips

The relationship between filtration rate and the resultant green body microstructure was examined for aqueous alumina slips cast at two different deflocculation states. The volume loading of both slips was 40%. Slip viscosities of 500 and 60 mPa·s were produced by different tetrasodium pyrophosphate additions. The filtration rate of these slips varied by a factor of 2; however, mercury porosimetry results showed the same average pore size for both samples. Single and multiple small-angle neutron scattering results showed the specimen cast with the higher-viscosity slip to possess a bimodal pore size distribution. The body cast with the low-viscosity slip showed unimodal porosity and, consequently, the filtration is attributed to the toroidal region between the packed particles. These results showed that mercury porosimetry does not provide a pore size that predicts filtration behavior of slips with different degrees of dispersion.     

"Planes, trains, automobiles--and tea sets: Extremely intense interests in very young children": Correction to DeLoache, Simcock, and Macari (2007).

Reports an error in "Planes, trains, automobiles--and tea sets: Extremely intense interests in very young children" by Judy S. DeLoache, Gabrielle Simcock and Suzanne Macari (Developmental Psychology, 2007[Nov], Vol 43[6], 1579-1586). The DOI for the supplemental materials was printed incorrectly. The correct DOI is as follows: http://dx.doi.org/10.1037/0012-1649.43.6.1579.supp. (The following abstract of the original article appeared in record 2007-16709-024.) Some normally developing young children show an intense, passionate interest in a particular category of objects or activities. The present article documents the existence of extremely intense interests that emerge very early in life and establishes some of the basic parameters of the phenomenon. Surveys and interviews with 177 parents revealed that nearly one third of young children have extremely intense interests. The nature of these intense interests is described, with particular focus on their emergence, commonalities in the content of the interests, and the reactions of other people to them. One of the most striking findings is a large gender difference: Extremely intense interests are much more common for young boys than for girls. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Is Perruchet’s dissociation between eyeblink conditioned responding and outcome expectancy evidence for two learning systems?

P. Perruchet (1985b) showed a double dissociation of conditioned responses (CRs) and expectancy for an airpuff unconditioned stimulus (US) in a 50% partial reinforcement schedule in human eyeblink conditioning. In the Perruchet effect, participants show an increase in CRs and a concurrent decrease in expectancy for the airpuff across runs of reinforced trials; conversely, participants show a decrease in CRs and a concurrent increase in expectancy for the airpuff across runs of nonreinforced trials. Three eyeblink conditioning experiments investigated whether the linear trend in eyeblink CRs in the Perruchet effect is a result of changes in associative strength of the conditioned stimulus (CS), US sensitization, or learning the precise timing of the US. Experiments 1 and 2 demonstrated that the linear trend in eyeblink CRs is not the result of US sensitization. Experiment 3 showed that the linear trend in eyeblink CRs is present with both a fixed and a variable CS–US interval and so is not the result of learning the precise timing of the US. The results are difficult to reconcile with a single learning process model of associative learning in which expectancy mediates CRs. (PsycINFO Database Record (c) 2010 APA, all rights reserved)