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1.
Pavel P. Fedorov Alexander A. Alexandrov Valery V. Voronov Mariya N. Mayakova Alexander E. Baranchikov Vladimir K. Ivanov 《Journal of the American Ceramic Society》2021,104(6):2836-2848
Phase formation in the SrF2–LaF3 system was studied at temperatures ranging from 300°C to 450°C using nitrate flux. The solubility of LaF3 in SrF2 decreases with decreasing temperature. The equilibrium width of the solid solution region Sr1−xLaxF2+x at 400°C, it is 44.6 ± 0.4 mol% LaF3 (x = 0.446), at 350°C — 38.3 ± 0.7 mol% LaF3 (x = 0.383), and decreases almost to zero at 300°C. 相似文献
2.
Mariya Pachman 《Computers & Education》2012,58(1):100-110
This study explores younger and older adults learning of MS Publisher functionalities from a multimedia tutorial. Twenty younger and twenty three older adults assigned to a redundant (experimental) or non-redundant (control) condition were taught how to create a greeting card, while the results of their learning were assessed with immediate and delayed performance measures. While younger learners benefited from a non-redundant condition, older learners exhibited an opposite trend. Redundant condition was beneficial for their performance efficiency on a set of a transfer tasks, and their troubleshooting performance during the delayed session. From a cognitive load perspective, using a redundant text along with an audio narration overloads learner’s working memory by placing more strain on the visual pathway and not providing any additional cognitive advantage. From an environmental support standpoint and decreased processing resources view of cognitive aging, providing additional representational support helps reducing the task demands for older adults and results in better learning. The results have cognitive and practical implications for the design of multimedia learning environments for older adults. 相似文献
3.
One‐pot synthesis of {Mo6I8}4+‐doped polystyrene microspheres via a free radical dispersion copolymerisation reaction
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Natalya A Vorotnikova Mariya V Edeleva Olga G Kurskaya Konstantin A Brylev Alexander M Shestopalov Yuri V Mironov Andrew J Sutherland Olga A Efremova Michael A Shestopalov 《Polymer International》2017,66(12):1906-1912
Molybdenum octahedral clusters, when incorporated into an appropriate polymer matrix, are considered as promising agents for a range of biological applications. This work describes the one‐pot synthesis, morphology and cellular toxicity of nano‐sized polystyrene beads doped with luminescent cluster complexes [{Mo6X8}(NO3)6]2? (X = Cl, Br or I). Specifically, the particles were obtained by free radical dispersion copolymerisation of styrene and methacrylic acid or 4‐vinylpyridine in the presence of the cluster complexes. The effects of the cluster loading in the reaction mixture on both the content of the final material and number‐average molar mass of the copolymers were evaluated. © 2017 Society of Chemical Industry 相似文献
4.
The ice surface softening by friction is investigated considering the additive non-correlated fluctuations of the shear strain and stress, and the temperature. The premelting is construed by the Kelvin–Voigt equation for shear strain and by the relaxation equations of Landau–Khalatnikov type for shear stress and temperature. Taking into account the noises in these equations, the Langevin and Fokker–Planck equations are derived. Their analysis is based on the investigation of extrema of the distribution function, i.e., steady-state values of the shear strain using the Stratonovich interpretation. The phase diagrams are constructed, where the noises intensities and thermostat temperature determine the regions of ice, softened ice and their mixture (stick–slip rubbing). We present that domain of ice friction is bounded by relatively small background sliding block temperatures and fluctuation intensities of the stress and temperature. The ice film softens with growth of the stress noise intensity even at small thermostat temperatures. The friction force time series for all rubbing modes are calculated and compared with experimentally observed ones. 相似文献
5.
Mariya Kyulavska Rayna Bryaskova Dimitriya Bozukova Rosa Mateva 《Journal of Polymer Research》2014,21(6):1-14
Novel series of poly (CL–co–Pluronic) polymers were successfully synthesized in situ by ring-opening polymerization (ROP) of ε-caprolactam (ε-CL). The copolymerization was activated by new type macroactivators (MAs) based on hydroxyl-terminated poly (ethylene oxide)-poly (propylene oxide)-poly (ethylene oxide) [PEO-PPO-PEO] triblock copolymers, known under the trade name Pluronic®. Toluene-2,4-diisocyanate (TDI) was used to obtain the isocyanate-terminated Pluronic prepolymers. The corresponding MAs were synthesized in situ with an N-carbamoyllactam structure. As an initiator of the copolymerization processes was used sodium lactamate (NaCL). To confirm the influence over the copolymerization process, microstructure, composition and molecular weight of the polymeric products two new types MAs based on Pluronic (P123 and F68) have been varied from 2 to 10 wt.% (vs. the monomer ε-CL). The structure of the both Pluronic based macroactivators (MAs) and accordingly obtained two series poly (CL-co-Pluronic) polymers were confirmed by 1H NMR and FT-IR analyses. Additionally, the structure, molecular weight, physicomechanical behavior, thermal stability and morphology of the new synthesized poly (CL–co–Pluronic) polymers have been investigated by Differential Scanning Calorimetry (DSC), Wide-Angle X-ray Diffraction (WAXD), Thermogravimetric Analysis (TGA) and Scanning Electron Microscopy (SEM) analysis. 相似文献
6.
Jiji Abraham Krishnan Sidhardhan Sisanth Ajesh Kulamamvila Zachariah Hanna Joseph Mariya Soney C. George Nandakumar Kalarikkal Sabu Thomas 《应用聚合物科学杂志》2020,137(46):49429
Obtaining strong interfacial interaction between filler and polymer matrix is very crucial for the fabrication of polymer nanocomposites with superior performance. Present study is aimed to fabricate high performance styrene butadiene rubber (SBR) nanocomposites with imidazolium type ionic liquid modified multiwalled carbon nanotube (MWCNT). Ionic liquid facilitates the dispersion of MWCNT in rubber matrix and it is obvious from transmission electron microscopy images. Diffusion of toluene through SBR nanocomposite membranes has been investigated as a function of surface modified MWCNT (f-MWCNT) content to analyze the chain dynamics and filler-polymer interactions. O2 gas barrier effect of nanocomposites with special reference to the filler loading is explored. The substantial improvement in the barrier effect in presence of filler interpreted on the grounds of a theoretical model describing permeability of heterogeneous systems. Finally solvent sensing characteristics of prepared nanocomposites are also analyzed and it is observed that prepared nanocomposites can be used as a flexible solvent sensor. 相似文献
7.
Jasdeep S. Gill Vasileios Theofylaktopoulos Andreas Mitsios Sarah Houston Ahmed M. Hagag Adam M. Dubis Mariya Moosajee 《International journal of molecular sciences》2022,23(8)
Pathogenic mutations in USH2A are a leading cause of visual loss secondary to non-syndromic or Usher syndrome-associated retinitis pigmentosa (RP). With an increasing number of RP-targeted clinical trials in progress, we sought to evaluate the photoreceptor topography underlying patterns of loss observed on clinical retinal imaging to guide surrogate endpoint selection in USH2A retinopathy. In this prospective cross-sectional study, twenty-five patients with molecularly confirmed USH2A-RP underwent fundus autofluorescence (FAF), spectral-domain optical coherence tomography (SD-OCT) and adaptive optics scanning laser ophthalmoscopy (AOSLO) retinal imaging. Analysis comprised measurement of FAF horizontal inner (IR) and outer (OR) hyperautofluorescent ring diameter; SD-OCT ellipsoid zone (EZ) and external limiting membrane (ELM) width, normalised EZ reflectance; AOSLO foveal cone density and intact macular photoreceptor mosaic (IMPM) diameter. Thirty-two eyes from 16 patients (mean age ± SD, 36.0 ± 14.2 years) with USH2A-associated Usher syndrome type 2 (n = 14) or non-syndromic RP (n = 2) met the inclusion criteria. Spatial alignment was observed between IR-EZ and OR-ELM diameters/widths (p < 0.001). The IMPM border occurred just lateral to EZ loss (p < 0.001), although sparser intact photoreceptor inner segments were detected until ELM disruption. EZ width and IR diameter displayed a biphasic relationship with cone density whereby slow cone loss occurred until retinal degeneration reached ~1350 μm from the fovea, beyond which greater reduction in cone density followed. Normalised EZ reflectance and cone density were significantly associated (p < 0.001). As the strongest correlate of cone density (p < 0.001) and best-corrected visual acuity (p < 0.001), EZ width is the most sensitive biomarker of structural and functional decline in USH2A retinopathy, rendering it a promising trial endpoint. 相似文献
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9.
本文用离子交换法制备K+交换玻璃光波导元件,并在其表面固定纳米级敏感层酞菁铜(CuPc)薄膜,利用光波导气体检测系统对NO2气体进行测试.结果表明,该传感元件常温下对NO2等气体有快速、可逆的响应,并具有重现性好,灵敏度高等特点. 相似文献
10.
Maryam Moshkelani Mariya Marinova Michel Perrier Jean Paris 《Applied Thermal Engineering》2013,50(2):1427-1436
Incorporating a biorefinery unit to an operating Kraft pulping process has significant technological, economic and social advantages over the construction of a grassroot biorefinery. Also, the conversion of a Kraft mill from total pulp making to complete biorefinery can be done in a stepwise fashion and so give a company that envisages such transformation the opportunity to master the new technologies, evaluate options and develop an appropriate business plan. In all cases however, the road to conversion presents serious challenges. As components of the wood such as lignin or hemicelluloses are withdrawn from the Kraft pulp line, the heat production capacity from the recovery boiler where they are currently burnt is diminished. At the same time the operation of the added biorefinery unit increases the steam demand. In order to avoid fossil fuel dependency, the total site must be highly integrated and optimized. The application of an intensive and innovative energy optimization methodology to actual case studies has shown that the green, low GHG emissions biorefinery is feasible. The economics can be attractive for a site combining specialty wood pulp and bio-product, biomass gasification, power cogeneration and heat upgrading by optimally positioned and designed absorption heat cycles. The methodology has been applied to biorefining technologies for lignin and hemicelluloses extraction and valorisation, both technologies being coupled with gasification of wood residue. 相似文献