The base‐mediated higher‐order 8+3‐cycloaddition reactions of heptafulvenes or azaheptafulvenes with α‐halohydroxamates have been achieved under mild and metal‐free conditions. These reactions do not ...only provide a direct route for the synthesis of highly functionalized cycloheptatriene‐fused piperidinones and piperazinones in moderate to excellent yields, but they also enrich the chemistry of heptafulvenes and azaheptafulvenes. Furthermore, gram‐scale reactions and further derivatizations demonstrated the synthetic potential of these cycloaddition reactions.
Base‐mediated higher‐order 8+3‐cycloaddition reactions of heptafulvenes or azaheptafulvenes with α‐halohydroxamates were developed. This strategy produced a variety of cycloheptatriene‐fused piperidinone and piperazinone derivatives in moderate to excellent yields under mild conditions.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
The relationships between the processing parameters (i.e. laser specific energy, powder density, preheated temperature of substrate and types of substrate) and the structure characteristics of ...Ni-based WC composite coatings during laser induction hybrid rapid cladding (LIHRC) were investigated systematically. The results show that laser specific energy, cladding height and contact angle have a linear relation with powder density, as can provide the predictions of laser processing parameters according to the geometrical characteristics of a single laser track (i.e. cladding height, cladding width). Moreover, dilution of composite coating increases with the increasing of laser specific energy and the preheated temperature of substrate, while reduces with the increasing of powder density. The types of substrate also have an important effect on dilution of composite coating, as has a strong dependence on the thermophysical properties of substrate (i.e. melting point, resistivity and permeability).
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Forages and concentrates have consistently distinct patterns of fermentation in the rumen, with forages producing more methane (CH
) per unit of digested organic matter (OM) and higher acetate to ...propionate ratio than concentrates. A mechanism based on the Monod function of microbial growth has been proposed to explain the distinct fermentation pattern of forages and concentrates, where greater dilution rates and lower pH associated with concentrate feeding increase dihydrogen (H
) concentration through increasing methanogens growth rate and decreasing methanogens theoretically maximal growth rate, respectively. Increased H
concentration would in turn inhibit H
production, decreasing methanogenesis, inhibit H
-producing pathways such as acetate production via pyruvate oxidative decarboxylation, and stimulate H
-incorporating pathways such as propionate production. We examined the hypothesis that equalizing dilution rates in serial rumen cultures would result in a similar fermentation profile of a high forage and a high concentrate substrate. Under a 2 × 3 factorial arrangement, a high forage and a high concentrate substrate were incubated at dilution rates of 0.14, 0.28, or 0.56 h
in eight transfers of serial rumen cultures. Each treatment was replicated thrice, and the experiment repeated in two different months. The high concentrate substrate accumulated considerably more H
and formate and produced less CH
than the high forage substrate. Methanogens were nearly washed-out with high concentrate and increased their initial numbers with high forage. The effect of dilution rate was minor in comparison to the effect of the type of substrate. Accumulation of H
and formate with high concentrate inhibited acetate and probably H
and formate production, and stimulated butyrate, rather than propionate, as an electron sink alternative to CH
. All three dilution rates are considered high and selected for rapidly growing bacteria. The archaeal community composition varied widely and inconsistently. Lactate accumulated with both substrates, likely favored by microbial growth kinetics rather than by H
accumulation thermodynamically stimulating electron disposal from NADH into pyruvate reduction. In this study, the type of substrate had a major effect on rumen fermentation largely independent of dilution rate and pH.
A series of Ni/Fe electrodes have been prepared by electrodeposition of metal salt precursors on different substrates. The surface morphology, chemical composition and electrochemical characteristics ...of these electrodes were studied by various physico-chemical techniques such as X-ray Photoelectron Spectroscopy (XPS) and Scanning Electron Microscopy (SEM). The electrochemical properties of the electrodes were examined by steady-state polarization curves. First, the influence of features such as Ni/Fe composition and type of substrate for the oxygen evolution reaction (OER) were determined by electrochemical techniques in a conventional 3-electrodes cell. The overpotential for the OER is lower for the electrodes with the higher concentrations of Ni. The electrodes with a Ni/Fe composition of 75/25 wt.% electrodeposited on steel mesh and/or 75/25 and 50/50 wt.% on nickel foam result in the most active configurations for the OER. These electrodes were further tested as anodes for alkaline water electrolysis during at least 70 h. In order to understand their activity and stability, the used electrodes were also characterized by SEM and compared to the fresh electrodes. Among the compositions and substrates examined, the Ni50Fe50-Nf electrode exhibited the lowest overpotential (2.1 V) for the OER and the higher stability as anode in an alkaline water electrolysis cell.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
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•The magnesium phthalocyanine (MgPc) baesed Schottky diodes are fabricated using four inorganic semiconductor (n-GaAs, n-Si, p-InP, p-Si) by the spin-coating.•This study reviews the ...crucial effect of (p and n) type conductivity of different material substrates on the electrical parameters of organic MgPc Schottky diodes for the use in such organic microelectronics applications.
The magnesium phthalocyanine (MgPc) based Schottky diodes are fabricated using four inorganic semiconductors (n-GaAs, n-Si, p-InP, p-Si)by the spin-coating process at 2000rpm for 1min. Their microelectronic and photoelectrical parameters are investigated from the current-voltage I–V characteristics measurements at room temperature in dark and under light. The ln I–V plots, Cheung and Norde methods are used to extract the MgPc based Schottky diodes parameters in dark, including ideality factor (n), barrier height (Φb), series resistance (Rs) and the obtained values are compared. The MgPc/n-Si showed excellent n of 1.1 which is very closer to ideal Schottky diode behavior, high Фb of 0.98eV and low series resistance of 237.77Ω in contrast MgPc/p-Si showed non-ideal Schottky diode behavior with n of 2.42 and high series resistance of 1.92×103Ω. The MgPc/p-InP exhibited photovoltaic behavior with excellent JSC of 3.11×103mA/cm2 and a photosensitivity of 30.46. The I–V forward bias in log scale have been investigated to survey the dominated conduction mechanism. This study reviews thecrucial effect of (p and n) type conductivity substrates on the electrical parameters of organic MgPc Schottky diodes for the use in such organic photovoltaic applications.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
The purpose of this study was to describe the spatial distribution of Trichoptera larvae in an area of fragmented Cerrado. We used additive partitioning for evaluating the most representative scale ...in terms of beta diversity and identifying differences in the pattern of partitioning between land uses. Four hierarchical levels were considered (substrate type, stream, microbasin, and land use) in five partitions (entire community, common genera, rare genera, livestock activity (LA), and subsistence activity). The most representative scale for the entire community was microbasin (β3 = 25.71%), for rare genera it was land use (β4 = 37.5%) and for common genera it was type of substrate (β1 = 28.75%). The comparison among land uses showed that the presence of LA changed the pattern of the distribution of beta diversity.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
The study on the influence of various initial population densities, various substrate type and various organic matter content on Chironomus plumosus population were carried out. The strong influence ...of population density on larval tube numbers was found. The average tube holes numbers per individual were, as a rule, higher than 1.0 at low (4-5 individuals/20 square c, densities of larvae. These numbers were usually much lower than 1.0 at high (40-80 ind. per 20 square cm densities, what indicates strong competition between larvae at their higher densities
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