Search results for " conversion"
showing 10 items of 447 documents
Application of the reduced I-V Blaesser’s characteristics in predicting PV modules and cells conversion efficiency in medium and high insolation cond…
2017
Abstract The article presents theoretical foundations of application of the reduced I-V Blaesser’s characteristics in predicting a photovoltaic cell/module (PV) efficiency, together with calculation procedures. A detailed analysis of the error of this transformation method of characteristics was carried out. Its practical application in predicting efficiency of operation of various PV cells and modules in medium and high insulation conditions was demonstrated. The practical suitability of the presented method in early detection of ageing phenomena, such as, for example, absorber degradation taking place in PV modules, was demonstrated. The article was prepared on the basis of the results of…
How activator ion concentration affects spectroscopic properties on Ba4Y3F17: Er3+, Yb3+, a new perspective up-conversion material
2018
Abstract Ba4Y3F17 with Er3+ and Yb3+, a promising material for up-conversion luminescence, was synthesized. Excellent isomorphic capacity was detected. Low-temperature measurements show that erbium ions are incorporated in multiple lattice positions, which is inconsistent with the current model of Ba4Y3F17 crystal lattice structure. Activator ion concentration has a different impact on 4S3/2 and 4F9/2, states (for the green and red luminescence, respectively) depopulation. Energy transfer from Er3+ 4S3/2 state to Yb3+ is observed even at low temperature (15 K) while Er-Er cross-relaxation is observed from 120 K and above. Yb3+ concentration has a great impact to red-to-green up-conversion l…
Using of reflections for expansion of frequency tuning in a THz-band gyrotron
2017
Effect of delayed reflection on operation of a second-harmonic THz-band gyrotron is studied. Theoretical analysis, numerical calculations and experimental observations for the 0.394 THz FU CW IIB gyrotron are presented.
Models for supercontinuum generation beyond the slowly-varying-envelope approximation
2014
International audience; We show numerically that both the modified Korteweg–de Vries and the sine-Gordon models are conducive to the generation of supercontinua with spectral bandwidths of several octaves, when an intense short pulse is launched as the initial condition. These models beyond the slowly-varying-envelope approximation could play an important role in modeling supercontinuum generation in gas-filled hollow waveguides.
Tetrasubstituted Thieno[3,2- b]thiophenes as Hole-Transporting Materials for Perovskite Solar Cells
2019
Three hole-transporting materials (HTMs) were prepared following a straightforward synthetic route by cross-linking arylamine-based ligands with a simple thieno[3,2-b]thiophene (TbT) core. The novel HTMs were fully characterized with standard techniques to gain insight into their optical and electrochemical properties and were incorporated in solution-processed mesoporous (FAPbI3)0.85(MAPbBr3)0.15 perovskite-based solar cells. The similar molecular structure of the synthesized HTMs was leveraged to investigate the role that the bridging units between the conjugated TbT core and the peripheral arylamine units plays on their properties and thereby on the photovoltaic response. A remarkable po…
Supported Polyhedral Oligomeric Silsesquioxane-Based (POSS) Materials as Highly Active Organocatalysts for the Conversion of CO2
2018
Very high turnover numbers (TON) and productivity values up to 7875 and 740 respectively have been obtained for the conversion of CO2 into cyclic carbonates by using hybrid materials based on imidazolium modified polyhedral oligomeric silsesquioxanes (POSS-Imi) grafted on amorphous silica (SiO2) and mesostructured SBA-15. The heterogeneous organocatalysts were easily prepared via a straightforward synthetic procedure allowing to generate high local concentration spots of imidazolium active sites surrounding the POSS core. This synthetic procedure is also a promising approach for the design of a wide library of hybrid functional materials. The materials do not possess other co-catalytic spec…
Encapsulation of black mulberry microcuttings: studies on capsules and synthetic seeds
2017
The encapsulation technology for plant tissue culture can be an efficient tool to optimize the plant management systems and to preserve valuable plant germplasm. In this paper, two experiments were carried out to evaluate the encapsulation efficiency in mulberry (Morus nigra L.). In the first experiment, gel capsules were stored at 4°C for different times (0, 30, 90, 180 and 360 days). The highest percentage of shoot viability (82.5%) and regrowth (72.5%) was scored after 180 days of storage, with an average development of 2.5 shoots/capsule. The second experiment was aimed to point out an efficient protocol to turn the capsules of black mulberry in synthetic seeds ready to develop into who…
Production performance and economic traits of silkworms (Bombyx mori L., 1758) fed with mulberry tree leaves (Morus alba, var. Ichinose) significantl…
2019
Abstract Production performance of silkworm (Bombyx mori L., 1758) play a pivotal role in sericulture industry and good quality cocoon represents the economic driver of farms. Silkworms are monophagus insects and differences between cocoon characteristics may depend both on mulberry tree leaves quality as well as on genetic selection of hybrid lines. While a huge work was carried out to identify the best feeding sources to optimize yields, genetic types of silkworms with desirable production and economic traits were studied to a limited extent to date. This experimental feeding trial was carried out using a commercial variety of mulberry tree leaves (Morus alba var. Ichinose) to feed a tota…
Coordination nano-space as stage of hydrogen ortho–para conversion
2015
The ability to design and control properties of nano-sized space in porous coordination polymers (PCPs) would provide us with an ideal stage for fascinating physical and chemical phenomena. We found an interconversion of nuclear-spin isomers for hydrogen molecule H 2 adsorbed in a Hofmann-type PCP, {Fe(pz)[Pd(CN) 4 ]} (pz=pyrazine), by the temperature dependence of Raman spectra. The ortho (o)–para (p) conversion process of H 2 is forbidden for an isolated molecule. The charge density study using synchrotron radiation X-ray diffraction reveals the electric field generated in coordination nano-space. The present results corroborate similar findings observed on different systems and confirm …
Catalytic conversion of glucose to 5-hydroxymethylfurfural over biomass-based activated carbon catalyst
2020
Selective and efficient dehydration of glucose to 5-hydroxymethylfurfural (HMF) has been widely explored research problem recently, especially from the perspective of more sustainable heterogeneous catalysts. In this study, activated carbon was first produced from a lignocellulosic waste material, birch sawdust. Novel heterogeneous catalysts were then prepared from activated carbon by adding Lewis or Brønsted acid sites on the carbon surface. Prepared catalysts were used to convert glucose to HMF in biphasic water:THF system at 160 °C. The highest HMF yield and selectivity, 51% and 78%, respectively, were obtained in 8 h with a catalytic mixture containing both Lewis and Brønsted acid sites…