Active optical fibres for application in laser and broadband ASE sources

2012 ◽  
Vol 60 (4) ◽  
pp. 673-682 ◽  
Author(s):  
D. Dorosz ◽  
J. Dorosz ◽  
A. Zając ◽  
J. Żmojda ◽  
M. Kochanowicz
Keyword(s):  
Spectral Range ◽  
Luminescence Properties ◽  
Optical Fibres ◽  
Drawing Process ◽  
Technological Parameters ◽  
Current Trends ◽  
Doped Glasses ◽  
Glass Matrices ◽  
Technological Constraints ◽  
The Impact

Abstract The article brings into focus the present state of technology employing active fibres doped with rare earth (RE) ions for applications requiring power supply of several dozen watts and broadband ASE sources. Current trends in development of glasses and in construction of active fibres used in fibre sources of radiation within VIS-NIR range are presented. Technological constraints in the doping of fibre core glasses are discussed, with particular consideration of optimal RE concentration for technical applications. Characteristics of glasses are offered, and the glasses are used for manufacturing optical fibres with luminescence within the visible as well as near- and mid-infrared ranges. Also, requirements and luminescence properties concerning glasses co-doped with e.g. Nd3+/Yb3+,Tm3+/Ho3+ and Yb3+/Tb3+ are discussed. Results of research on the impact of technological parameters of glass matrices on luminescence properties of core glasses and optical fibres are quoted. For the doped glasses of which luminescence in a wide spectral range is desired, conditions for their processing into optical fibre systems are mentioned. Additionally, the impact of phonon energy in the glass on producing emission in a specified spectral range is analyzed. Furthermore, the article presents directions of technological studies to solve problems persisting in the phase of glass matrix design, as well as in determining the influence of fibre drawing process on the luminescence properties of core glasses and optical fibres, confirming the differences in luminescence stemming from the drawing process. Finally, some original designs of core glasses and active multicore fibre systems devised for construction of fibre radiation sources are presented.

scholarly journals Influence of Glass Composition on the Luminescence Mechanisms of CdSe Quantum Dot-Doped Glasses

2021 ◽  
Author(s):  
Wenke Li ◽  
Xiujian Zhao ◽  
Chao Liu ◽  
François-Xavier Coudert
Keyword(s):  
Quantum Dot ◽  
Atomic Structure ◽  
Density Functional ◽  
Glass Composition ◽  
Matrix Composition ◽  
Na2o Content ◽  
Cdse Quantum Dot ◽  
Doped Glasses ◽  
Glass Matrices ◽  
The Impact

<div> <div> <div> <p>In this work, we characterized the electronic structure of CdSe quantum dots embedded in a series of x Na2O, (1–x) SiO2 glass matrices (x = 0, 0.25, 0.33 and 0.5). We analyzed the impact of the glass matrix composition on both the atomic structure of the quantum dot (QD) and the QD/glass interface, as well as the luminescence mechanisms, using density functional theory (DFT) calculations. The increase of Na2O content in the glass matrices was found to promote the formation of Cd–O and Se–Na interfacial bonds, and disrupting the Cd–Se bonds network. In particular, we show that the glass composition directly affects the nature of the highest occupied molecular orbitals (HOMO). According to the atomic structure, the band gap distribution and the density of states calculation, we find that there is significant reconstruction of the QD, and that the picture sometimes proposed of a “pristine QD” surrounded by glass is not realistic. The introduction of CdSe QD significantly decreased the bandgap of the glass compared to pristine glasses, and the interfacial bonds greatly contributed to the frontier orbitals without forming midgap states. We propose a new energy diagram, quite different from the traditional model, to explain the luminescence of CdSe quantum dot- doped glasses, originating from the intrinsic emission of this hybrid system {QD + glass}. These results improve our understanding of the luminescence of CdSe quantum dot-doped glasses, explaining the reason for the poor quantum efficiency and broad emission linewidth compared with their colloidal counterparts. </p> </div> </div> </div>

scholarly journals Influence of Glass Composition on the Luminescence Mechanisms of CdSe Quantum Dot-Doped Glasses

2021 ◽  
Author(s):  
Wenke Li ◽  
Xiujian Zhao ◽  
Chao Liu ◽  
François-Xavier Coudert
Keyword(s):  
Quantum Dot ◽  
Atomic Structure ◽  
Density Functional ◽  
Glass Composition ◽  
Matrix Composition ◽  
Na2o Content ◽  
Cdse Quantum Dot ◽  
Doped Glasses ◽  
Glass Matrices ◽  
The Impact

<div> <div> <div> <p>In this work, we characterized the electronic structure of CdSe quantum dots embedded in a series of x Na2O, (1–x) SiO2 glass matrices (x = 0, 0.25, 0.33 and 0.5). We analyzed the impact of the glass matrix composition on both the atomic structure of the quantum dot (QD) and the QD/glass interface, as well as the luminescence mechanisms, using density functional theory (DFT) calculations. The increase of Na2O content in the glass matrices was found to promote the formation of Cd–O and Se–Na interfacial bonds, and disrupting the Cd–Se bonds network. In particular, we show that the glass composition directly affects the nature of the highest occupied molecular orbitals (HOMO). According to the atomic structure, the band gap distribution and the density of states calculation, we find that there is significant reconstruction of the QD, and that the picture sometimes proposed of a “pristine QD” surrounded by glass is not realistic. The introduction of CdSe QD significantly decreased the bandgap of the glass compared to pristine glasses, and the interfacial bonds greatly contributed to the frontier orbitals without forming midgap states. We propose a new energy diagram, quite different from the traditional model, to explain the luminescence of CdSe quantum dot- doped glasses, originating from the intrinsic emission of this hybrid system {QD + glass}. These results improve our understanding of the luminescence of CdSe quantum dot-doped glasses, explaining the reason for the poor quantum efficiency and broad emission linewidth compared with their colloidal counterparts. </p> </div> </div> </div>

Klára Buzássyová V Kontexte Sémantizácie Slovenskej Lexiky Cudzincom

2018 ◽  
Vol 69 (3) ◽  
pp. 616-625
Author(s):  
Jana Pekarovičová
Keyword(s):  
Foreign Language ◽  
Foreign Students ◽  
Summer School ◽  
European Language ◽  
Dynamic Changes ◽  
Language And Culture ◽  
Current Trends ◽  
Communication Needs ◽  
The Impact ◽  
Slovak Language

Abstract This paper deals with the characteristics of the scientific research of the renowned Slovak linguist Klára Buzássyová who – as a lecturer at the Studia Academica Slovaca summer school of Slovak language and culture – presented to foreign students the specifics of Slovak lexis and their function in speech within the context of intraand interlingual relationships. In her lectures, she helped students to see Slovak as a developped and modern Central European language which has its own genetic and typological properties and as a language capable of reacting to dynamic changes emerging from the communication needs of language users while respecting current trends in European language policy. Klára Buzássyová presented students with the latest results of her linguistic research and discussed the issues regarding the dynamics of vocabulary with an emphasis on the methods of wordformation, motivation, and the impact on the semantic and stylistic value of lexical units. Her papers, published in the Studia Academica Slovaca proceedings from 1980 to 2001 presented her scientific orientation and became an inspiration for the linguistic and didactic conception of Slovak as a foreign language in the context of the development of Slovak studies in Slovakia as well as abroad.

Peculiarities of tool material wear at polymeric composite blank cutting

2018 ◽  
Vol 2018 (7) ◽  
pp. 27-31
Author(s):  
Юрий Зубарев ◽  
Yuriy Zubarev ◽  
Александр Приемышев ◽  
Alexsandr Priyomyshev
Keyword(s):  
Tool Wear ◽  
Tool Material ◽  
Polymeric Composite ◽  
Physical Models ◽  
Technological Parameters ◽  
Tool Materials ◽  
Materials Used ◽  
The Impact ◽  
Material Wear

Tool materials used for polymeric composite blank machining, kinds of tool material wear arising at machining these blanks, and also the impact of technological parameters upon tool wear are considered. The obtained results allow estimating the potentialities of physical models at polymeric composite blanks cutting.

Designing a creative programming unit within the elementary school core curriculum

2020 ◽  
Author(s):  
Yumiko Murai ◽  
Ryohei Ikejiri ◽  
Yuhei Yamauchi ◽  
Ai Tanaka ◽  
Seiko Nakano
Keyword(s):  
Core Curriculum ◽  
Design Research ◽  
Empirical Studies ◽  
School Curriculum ◽  
Educational Design ◽  
Current Trends ◽  
Educational Design Research ◽  
Creative Learning ◽  
Uncertain Future ◽  
The Impact

Cultivating children’s creativity and imagination is fundamental to preparing them for an increasingly complex and uncertain future. Engaging in creative learning enables children to think independently and critically, work cooperatively, and take risks while actively engaging in problem solving. While current trends in education, such as maker movements and computer science education, are dramatically expanding children’s opportunities for engagement in creative learning, comparatively few empirical studies explore how creative learning can be integrated into the school curriculum. The educational design research described in this paper focuses on a curriculum unit that enables students to engage with creative learning through computer programming activities while meeting curriculum goals. The data provided in this paper were drawn from three classroom tryouts, the results of which were used to drive an iterative design process. This paper also shares several insights on the impact of creative learning in curriculum teaching.

scholarly journals Successive Harvests Modulate the Productive and Physiological Behavior of Three Genovese Pesto Basil Cultivars

Agronomy ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 560
Author(s):  
Luigi Formisano ◽  
Michele Ciriello ◽  
Christophe El-Nakhel ◽  
Marios C. Kyriacou ◽  
Youssef Rouphael
Keyword(s):  
Dry Matter ◽  
Co2 Assimilation ◽  
Stomatal Resistance ◽  
Matter Content ◽  
Dry Matter Content ◽  
Technological Parameters ◽  
Net Co2 Assimilation ◽  
Dry Biomass ◽  
Crop Cycle ◽  
The Impact

In the Italian culinary tradition, young and tender leaves of Genovese basil (Ocimum basilicum L.) are used to prepare pesto sauce, a tasty condiment that attracts the interest of the food processing industry. Like other leafy or aromatic vegetables, basil is harvested more than once during the crop cycle to maximize yield. However, the mechanical stress induced by successive cuts can affect crucial parameters associated with pesto processing (leaf/stem ratio, stem diameter, and dry matter). Our research accordingly aimed to evaluate the impact of successive harvests on three field-grown Genovese basil cultivars (“Aroma 2”, “Eleonora” and “Italiano Classico”) in terms of production, physiological behavior, and technological parameters. Between the first and second harvest, marketable fresh yield and shoot dry biomass increased by 148.4% and 172.9%, respectively; by contrast, the leaf-to-stem ratio decreased by 22.5%, while the dry matter content was unchanged. The increased fresh yield and shoot dry biomass at the second harvest derived from improved photosynthetic efficiency, which enabled higher net CO2 assimilation, Fv/Fm and transpiration as well as reduced stomatal resistance. Our findings suggest that, under the Mediterranean environment, “Italiano Classico” carries superior productive performance and optimal technological characteristics in line with industrial requirements. These promising results warrant further investigation of the impact successive harvests may have on the qualitative components of high-yielding basil genotypes with respect to consumer expectations of the final product.

Andrew Chien Speaks Out on the Impact of Current Trends in Architecture

2019 ◽  
Vol 47 (4) ◽  
pp. 17-22
Author(s):  
Marianne Winslett ◽  
Vanessa Braganholo
Keyword(s):  
Current Trends ◽  
The Impact

Tolstoy in a recipe

2014 ◽  
Vol 44 (4) ◽  
pp. 310-323 ◽  
Author(s):  
Ana Tominc
Keyword(s):  
Design Methodology ◽  
The Other ◽  
Food Culture ◽  
Content Type ◽  
Current Trends ◽  
New Middle Class ◽  
Cooking Shows ◽  
Local Construction ◽  
The Impact ◽  
The Relationship

Purpose – The purpose of this study is to demonstrate the impact of global celebrity chefs and their discourse about food on the genre of cookbooks in Slovenia. Design/methodology/approach – Focusing this discourse study on cookbook topics only, the analysis demonstrates the relationship between the aspirations of local celebrity chefs for the food culture represented globally by global celebrity chefs, such as Oliver, and the necessity for a local construction of specific tastes. While the central genre of TV celebrity chefs remains TV cooking shows, their businesses include a number of side products, such as cookbooks, which can be seen as recontexualisations of TV food discourse. Findings – Hence, despite this study being limited to analysis of cookbooks only, it can be claimed that the findings extend to other genres. The analysis shows that local chefs aspire to follow current trends, such as an emphasis on the local and sustainable production of food as well as enjoyment and pleasure in the form of a postmodern hybrid genre, while, on the other hand, they strive to include topics that will resonate locally, as they aim to represent themselves as the “new middle class”. Originality/value – Such an analysis brings new insights into the relationship between discourse and globalisation as well as discourse and food.

scholarly journals Thermographic Study of Chip Temperature in High-Speed Dry Milling Magnesium Alloys

2016 ◽  
Vol 7 (2) ◽  
pp. 86-92 ◽  
Author(s):  
Józef Kuczmaszewski ◽  
Ireneusz Zagórski ◽  
Piotr Zgórniak
Keyword(s):  
Temperature Measurement ◽  
Magnesium Alloys ◽  
High Speed ◽  
Machining Process ◽  
Dry Milling ◽  
Technological Parameters ◽  
Chip Temperature ◽  
Thermographic Study ◽  
On Chip ◽  
The Impact

Abstract This paper presents an overview of the state of knowledge on temperature measurement in the cutting area during magnesium alloy milling. Additionally, results of own research on chip temperature measurement during dry milling of magnesium alloys are included. Tested magnesium alloys are frequently used for manufacturing elements applied in the aerospace industry. The impact of technological parameters on the maximum chip temperature during milling is also analysed. This study is relevant due to the risk of chip ignition during the machining process.

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