Nauki Ścisłe i Przyrodnicze
https://repozytorium.ukw.edu.pl///handle/item/8
2024-03-19T03:28:28ZColor converters for white LEDs using liquid phase epitaxy growth method
https://repozytorium.ukw.edu.pl///handle/item/8146
Color converters for white LEDs using liquid phase epitaxy growth method
Markovskyi, Anton; Gorbenko, Vitaliy; Zorenko, Tetiana; Fedorov, A.; Zorenko, Yuriy
The development of innovative high-power lighting sources is urgently required to design and investigate the new high structural quality and high-temperature stable converters in the form of single crystals and single crystalline films. This research deals with the growth and investigation of structural, luminescence, and photoconversion properties (color coordinates, color temperature and color rendering index) of the single crystalline films of Ce3+ doped (Lu, Y, Tb, Gd)3Al5O12 garnets, grown using the Liquid Phase Epitaxy method onto undoped Y3Al5O12 substrates. The combination of Ce3+ doped Lu3Al5O12, Y3Al5O12, Tb3Al5O12, Gd2.9Lu0.1Al5O12 film converter with respective thickness with commercial blue LED allows for obtaining green-yellow-orange-emitting pc-WLEDs. The application of the mentioned film converters results in the formation of four basic trends on the color diagram depending on the thickness of the converter.
2024-01-01T00:00:00ZLuminescence and photoconversion properties of Ce-doped Ca3Sc2Si3O12 crystal
https://repozytorium.ukw.edu.pl///handle/item/8145
Luminescence and photoconversion properties of Ce-doped Ca3Sc2Si3O12 crystal
Shakhno, Anna; Gieszczyk, W.; Bilski, P.; Witkiewicz-Łukaszek, Sandra; Zorenko, Tetiana; Cieszko, Mieczysław; Szczepański, Zbigniew; Kotlov, A.; Zorenko, Yuriy
This work is dedicated to investigation of the luminescent properties of the prospective photoconversion material based on the crystal of Ce3+ doped Ca3Sc2Si3O12 (CSSG) garnet. The GSSG:Ce crystal was grown using the micro-pulling-down (μPD) method. The CSSG:Ce crystal exhibited an intensive photoluminescence (PL) emission band with two sub-bands peaked at 504 and 545 nm, corresponding to 5d-4f (2F5/2;7/2) transitions. Furthermore, we have investigated also the formation of cerium multicenters in the GSSG:Ce crystal using analyses of the structure of Ce3+ photoluminescence emission and excitation spectra under excitation of the luminescence of this crystal by synchrotron radiation. The formation of Ce3+-multicenters in CSSG:Ce garnet is caused by the local inhomogeneity of the dodecahedral sites of garnet lattice due to localization of the hetero-valent Sc3+ and Si4+ cations in the octahedral and tetrahedral positions of the garnet host. The existence of Ce3+ multicenters resulted in a significant enhancement of the Ce3+ emission band in the red range and improving the performance of conventional YAG:Ce phosphor. The next task of our work was to evaluate the possibility of application of the GSSG:Ce crystal as a light phosphor-converter (pc) for white light-emitting diodes (WLEDs). In the frame of this task, we have successfully developed a prototype of WLED by employing the CSSG:Ce crystal as a phosphor-converter (pc) with blue 450 emitting LED as well as investigated the color characteristics of this pc-WLED.
2024-01-01T00:00:00ZLeveraging Information and Communication Technologies in Forest Ecotourism: A Case Study from Poland
https://repozytorium.ukw.edu.pl///handle/item/8127
Leveraging Information and Communication Technologies in Forest Ecotourism: A Case Study from Poland
Kozłowska-Adamczak, Monika; Essing-Jelonkiewicz, Patrycja; Jezierska-Thole, Aleksandra
Ecotourism encompasses various forms of tourism which are implemented in accordance with the principles of sustainable development of the EU. They maintain a balance between the three pillars of sustainable development: economic development, sustainable use of natural resources, and respect for social and cultural values. Ecotourism in forests holds particular significance due to its ability to sustain the ecological, social, and economic integrity of these areas. Activities promoting access to forests focus on ensuring a safe and enriching experience for forest users while simultaneously conserving nature. In response to the needs of forest tourism and recreation enthusiasts, innovative developments and new information and communications technologies (ICTs) such as websites, web platforms, mobile apps, QR codes, and others are being introduced with increasing frequency. These technologies already have a wide range of applications in providing access to tourism information and services in other sectors of tourism management and are now supplanting conventional sightseeing information systems. This paper aims to present the activities currently underway in connection with the development of a new tourism and recreation offering in the forests owned by the State Treasury and managed by the State Forests National Forest Holding in Poland. The research involved conducting an environmental survey among representatives of all forest districts in Poland (n = 425). A questionnaire survey was created using the Microsoft Forms web-based programme and made available online to representatives of all State Forests’ forest districts in Poland participating in the Stay Overnight in the Forest programme. The scope of this paper covers the present day, with a primary focus on desk research and analysis of statistics and source materials pertaining to the period from 2007 to 2022, retrieved from internal documents and reports prepared by the General Directorate of the State Forests. The research demonstrated that technological innovations such as mobile apps, social media, websites, web portals, and YouTube TV, when employed for developing forest tourism and forest recreation in Poland, can contribute to the advancement of the forest’s non-productive role, namely, a social role and in particular, the tourism, leisure, and recreational function of the State Forests.
2024-01-01T00:00:00ZJudocy Uniwersytetu Kazimierza Wielkiego
https://repozytorium.ukw.edu.pl///handle/item/8036
Judocy Uniwersytetu Kazimierza Wielkiego
Pujszo, Ryszard
W książce zaprezentowano sylwetki sportowców związanych z uczelnią, począwszy od roku 1969 aż po rok 2010. Z przedstawionych biogramów dowiadujemy się o wyczynach sportowych, pasjach i planach ludzi sportu.
2012-01-01T00:00:00Z