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This article reports on the use of Rasch modelling to develop and validate an instrument measuring self-efficacy in tutoring children in primary mathematics (SETcPM). In response to the literature on teacher efficacy, the 20-item instrument aims to inform teacher educators, and is designed for novice pre-service teachers (nPSTs) preparing to teach mathematics in primary school (grades 1–7, ages 6–13). To ensure that the tasks of teaching are imaginable for nPSTs, the instrument targets the core activity of teaching mathematics: helping a generic child with mathematics tasks. We propose that SETcPM is measurable for the intended population and represents a central part of self-efficacy in teaching mathematics (SETM). Understanding the initial SETcPM of novices and mapping its development over the course of their training programme can contribute to a better understanding of SETM, and allow teacher educators to tailor their support. 相似文献
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We consider a multidimensional diffusion X with drift coefficient b(α,Xt) and diffusion coefficient ?σ(β,Xt). The diffusion sample path is discretely observed at times tk=kΔ for k=1…n on a fixed interval [0,T]. We study minimum contrast estimators derived from the Gaussian process approximating X for small ?. We obtain consistent and asymptotically normal estimators of α for fixed Δ and ?→0 and of (α,β) for Δ→0 and ?→0 without any condition linking ? and Δ. We compare the estimators obtained with various methods and for various magnitudes of Δ and ? based on simulation studies. Finally, we investigate the interest of using such methods in an epidemiological framework. 相似文献
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Luiza-Andreea Tnase Oana-Viorela Nistor Gabriel-Dnu Mocanu Doina-Georgeta Andronoiu Adrian Cîrciumaru Elisabeta Botez 《Molecules (Basel, Switzerland)》2022,27(22)
Galactagogue herbs, also known as natural lactation adjuvants, are frequently used to stimulate breast milk production. Due to their antioxidant activity and phenolic content, anise (Pimpinella anisum L.) and fennel (Foeniculum vulgare L.) were chosen to increase the added value of zucchini (Cucurbita pepo L.) purees. At the same time, this work aimed to determine the influence of heat treatment on various characteristics of the final product. The phytochemical content, color parameters, and rheological and textural parameters of zucchini purees enriched with herbal aqueous extracts were determined after processing and after one week of storage (4 °C). In the case of antioxidant activity, samples registered a variation between 6.62 ± 1.71 and 38.32 ± 3.85 µM Trolox/g DW for the samples processed by steam convection. The total difference color parameter (ΔE) increased seven times after one week of storage compared to samples at T0. Fennel and anise aqueous extracts helped improve the rheological behavior of zucchini samples both by steam and hot air convection. This study may serve as a springboard for future investigations and clinical trials into the scientific validity and safety of ready-to-eat foods with special destinations. 相似文献
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Mastropietro TF Yadav YJ Szerb EI Talarico AM Ghedini M Crispini A 《Dalton transactions (Cambridge, England : 2003)》2012,41(29):8899-8907
The synthesis, crystal structure and luminescence properties of three cyclometalated Ir(III) complexes of general formula [(ppy)(2)Ir(pam)]X, where X = Cl(-) (1), PF(6)(-) (2), ClO(4)(-)(3), and pam = 2-picolylamine, are described. While 2 and 3 crystallize in a unique form, two pseudo-polymorphs, a solvated (1a) and a non-solvated (1b) species, have been observed for compound 1. 1a crystallizes in the monoclinic centrosymmetric space group P2(1)/c. On the contrary, 1b, 2 and 3 crystallize in the non-centrosymmetric space group P2(1)2(1)2(1) (1b) and Pca2(1) (2 and 3), respectively. All the crystalline supramolecular materials have been fully photophysically characterized. While 1 shows a bright blue-green emission in both solution and solvated crystalline state 1a, crystals of 1b, 2 and 3 show a significantly red shifted emission with respect to solution. Unexpectedly, and differently from 1a, mechanical stimuli-responsive colour and luminescence changes have been observed for 1b, 2 and 3. Upon mechanical grinding the colour of the crystalline solids changes from orange to yellow while the emission energy is partially (2 and 3) or completely (1b) converted from orange to green. The grinding-triggered colour and luminescence changes have been attributed to a crystal-to-amorphous phase conversion for all crystalline solids. 相似文献
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Adelina-Antonia Andelescu Dr. Benoît Heinrich Maria Angela Spirache Emilie Voirin Prof. Massimo La Deda Giuseppe Di Maio Dr. Elisabeta I. Szerb Dr. Bertrand Donnio Dr. Otilia Costisor 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(21):4850-4860
Blue–green luminescent terpyridine-containing PtII and ZnII complexes are reported. Equipped with lipophilic gallate units, which act as monodentate ancillary coordinating ligands and/or as anions, they display low-temperature mesomorphic properties (lamello-columnar and hexagonal mesophases for PtII and ZnII complexes, respectively). The mesomorphic properties were investigated by polarised optical microscopy, differential scanning calorimetry, thermogravimetric analysis and X-ray scattering of bulk materials and oriented thin films. The model of self-assembly into the lamello-columnar phase of the PtII complex has been described in detail. The optical properties of the complexes were investigated in the liquid and condensed liquid crystalline states, highlighting the delicate balance between the role of the metal in determining the type of excited state responsible for the emission, and the role of the ancillary ligand in driving intermolecular interactions for proper mesophase formation. 相似文献
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Horvath-Bordon E Riedel R Zerr A McMillan PF Auffermann G Prots Y Bronger W Kniep R Kroll P 《Chemical Society reviews》2006,35(10):987-1014
Besides temperature at one atmosphere, the applied pressure is another important parameter for influencing and controlling reaction pathways and final reaction products. This is relevant not only for the genesis of natural minerals, but also for synthetic chemical products and technological materials. The present critical review (316 references) highlights recent developments that utilise high pressures and high-temperatures for the synthesis of new materials with unique properties, such as high hardness, or interesting magnetic or optoelectronic features. Novel metal nitrides, oxonitrides as well as the new class of nitride-diazenide compounds, all formed under high-pressure conditions, are highlighted. Pure oxides and carbides are not considered here. Moreover, syntheses under high-pressure conditions require special equipment and preparation techniques, completely different from those used for conventional synthetic approaches at ambient pressure. Therefore, we also summarize the high-pressure techniques used for the synthesis of new materials on a laboratory scale. In particular, our attention is focused on reactive gas pressure devices with pressures between 1.2 and 600 MPa, multi-anvil apparatus at P < 25 GPa and the diamond anvil cell, which allows work at pressures of 100 GPa and higher. For example, some of these techniques have been successfully upgraded to an industrial scale for the synthesis of diamond and cubic boron nitride. 相似文献
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Ghiulendan Aptisa Fernando Benavente Victoria Sanz-Nebot Elisabeta Chirila José Barbosa 《Analytical and bioanalytical chemistry》2010,396(4):1571-1579
Modelling electrophoretic mobility as a function of pH can be simultaneously used for determination of ionization constants
and for rapid selection of the optimum pH for separation of mixtures of the modelled compounds. In this work, equations describing
the effect of pH on electrophoretic behaviour were used to investigate migration of a series of polyprotic amphoteric peptide
hormones between pH 2 and 12 in polybrene-coated capillaries. Polybrene (hexadimethrin bromide) is a polymer composed of quaternary
amines that is strongly adsorbed by the fused-silica inner surface, preventing undesired interactions between the peptides
and the inner capillary wall. In polybrene-coated capillaries the separation voltage must be reversed, because of the anodic
electroosmotic flow promoted by the polycationic polymer attached to the inner capillary wall. The possibility of using polybrene-coated
capillaries for determination of accurate ionization constants has been evaluated and the optimum pH for separation of a mixture
of the peptide hormones studied has been selected. Advantages and disadvantages of using bare fused-silica and polybrene-coated
capillaries for these purposes are discussed. 相似文献
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Marin Cernea Mihail Secu Corina Elisabeta Secu Mihaela Baibarac Bogdan S. Vasile 《Journal of nanoparticle research》2011,13(1):77-85
In this study, we report on the nanocrystalline powders of TiO2 and Fe-doped TiO2 (anatase and rutile phases) prepared by sol–gel method. The X-ray diffraction and Raman spectroscopy measurements indicated
the presence of anatase or rutile phase in nanopowders. TEM micrographs showed 10 and 112 nm average particle sizes for anatase
and rutile, respectively. Furthermore, their thermoluminescence properties were analyzed. 相似文献
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Marin Cernea Corina Elisabeta Secu Bogdan Stefan Vasile Mihail Secu 《Current Applied Physics》2013,13(1):137-141
Nanocrystalline Tm3+(5%)-doped BaTiO3 (BT-Tm) has been synthesized by the sol–gel method. The morphology, structure, and optical properties of powders and ceramics were characterized. The average grain size of the gel precursor annealed at 700 and 900 °C was 20 nm and 30 nm, respectively. These powders were single phase and crystallized with a cubic structure while the BT-Tm sintered ceramics were crystallized with the tetragonal BaTiO3 structure. The photoluminescence spectra showed typical transitions of Tm3+ ions and a structure consistent with the Tm3+ ions incorporation in the BaTiO3 crystalline lattice. Thermoluminescence peaks recorded at 300 °C (for annealed samples) or at 230 °C for the ceramic sample were assigned to the recombination of the Tm2+-electron traps located mainly at the surface of the nano-crystals or inside the microcrystals, respectively. 相似文献