137 research outputs found
Photonic nanojet mediated Raman enhancement: Vertical Raman mapping and simple ray matrix analysis
No full textA new method for enhancing the Raman scattering signal has emerged recently, based on dielectric enhancement. Especially promising is the dielectric method based on microspheres and photonic nanojet. In this paper, geometrical aspects and the influence of the incident beam parameters on Raman enhancement by silica microspheres were systematically investigated in three steps: by characterizing the incident beam using knife-edge method, performing horizontal and vertical Raman mapping imaging, and analyzing the results using ray transfer matrix analysis. Maps show a distinct enhancement (hotspot) area caused by the microsphere photonic nanojet and lens effect compared to a plain silicon substrate. Enhancement value on maps was the highest (5.7×) for 0.50 numerical aperture objective, when the incident beam size matched the microsphere diameter, and the focus of the incident beam was below the top of the sphere, so that the output beam focus was at the microsphere–substrate contact area. This geometrical configuration was confirmed as ideal by performing simple ray transfer matrix analysis. The ideal ranges of incident and output beam parameters match with the measured hotspot area. This three-step process and the usage of vertical Raman mapping have been, for the best of our knowledge, performed for the first time in such configuration. This research introduces a new way of investigating microsphere-assisted Raman enhancement, offers different approach to microsphere optics research, and improves current knowledge of the influence of the incident beam on the enhancement
Improving the research capabilities of four year old children in the center of science studies
No full textKvalifikācijas darbs: Četrgadīgu bērnu pētniecisko prasmju pilnveide dabas zinību mācību jomas centrā. Darba autore: Ivanda Balsa Darba zinātniskā vadītāja: profesore, Dr.paed. Maruta Sīle Pētījuma mērķis: Pētīt pētniecisko prasmju pilnveides iespējas dabas mācību jomas centrā četru gadu veciem bērniem. Pētījuma uzdevumi: 1.Analizēt zinātniskās teorijas par pētnieciskajām prasmēm, 2. Raksturot pētnieciskās prasmes četrgadīgiem bērniem, 3. Organizēt empīrisko pētījumu un pamatot metožu izvēli, 4. Analizēt empīriskā pētījuma iegūtos datus. Darba ietvaros tika organizēts un veikts empīriskais pētījums pirmsskolas izglītības iestādē “X” par pētniecisko prasmju pilnveides iespējām dabas zinību mācību jomā. Pētījumā piedalījās 15 bērni vecumā no 4 līdz 4,6 gadiem. Sākotnēji tika noteikts bērnu pētniecisko prasmju līmenis, pēc tam tika izstrādāti un aprobēti pedagoģiskie paņēmieni bērnu pētniecisko prasmju pilnveidei. Pēc izstrādātajām metodēm, kuru pamatā bija ievērot bērna iepriekšējā dzīves pieredzi, bērnu viedokļu noskaidrošana un grūtības pakāpes ievērošana atbilstoši vecumam, var secināt, ka bērnu pētnieciskās prasmes rezultātā ir uzlabojušās. Salīdzinājumā ar pētījuma sākuma datiem, kad 60% bērnu grupā bija zems un 40% bērnu bija vidējs pētniecisko prasmju līmenis, pētījuma noslēgumā 7% zems, 73% vidējs un 20% augsts līmenis. Kvalifikācijas darba apjoms: kvalifikācijas darba apjoms ir 45lpp. (neskaitot pielikumus), darbā izmantotas 7 tabulas, 5 attēli, 44 izmantotās literatūras avoti un 3 pielikumi. Atslēgas vārdi: pētniecība, prasme, četrgadnieks, bērns, dabaszinības, pirmsskola.Qualification work: Improving the research capabilities of four year old children, in the center of science studies. Author of the work: Ivanda Balsa Scientific supervisor: professor.Dr.paed. Maruta Sīle Aim of the research: To study the possibilities of improving research skills in the nature center for four-year-old children. Research tasks: •to analyze scientific theories about research skills, •to describe research skills for four-year-old children, •to organize research and justify the choice of methods, •analyze the obtained data. Volume of qualification work: the volume of qualification work is 45 pages. (excluding appendices), 7 tables, 5 figures, 44 references and 3 appendices were used in the work. Within the framework of the work, an empirical study was organized and conducted in the pre-school educational institution “X” on the possibilities of improving research skills in the field of natural sciences. The study involved 15 children aged 4 to 4.6 years. Initially, the level of children's research skills was determined, then methods were developed for the improvement of children's research skills in the field of natural sciences. According to the developed methods, which were based on taking into account the child's previous life experience, expressing the child's opinion and the degree of difficulty according to age, it can be concluded that the children's research skills have improved. Compared to the baseline data, 60% of the children in the group had a low level of research skills and 40% had a medium level of research skills, but at the end of the study 7% were low, 73% were medium, and 20% were high. Keywords: research, skill, four-year-old, child, natural sciences, preschoo
Nucleation of titania nanocrystals in silica titania waveguides
No full textSiO2(1−x)-TiO2(x) monomode waveguides at 632.8 nm, with x in the range 0.07–0.2 and thickness of
about 0.4 μm, were deposited on silica substrates by a dip-coating technique. Nucleation of TiO2 nanocrystals
and the growth of their size by thermal annealing up to 1300◦C were studied by waveguided Raman scattering in
the SiO2(0.8)-TiO2(0.2) composition. In the low frequency region (5–50 cm−1) of the VV and HV polarized Raman
spectra the symmetric and quadrupolar acoustic vibrations are observed. The mean size of the titania particles are
obtained from the frequencies of the Raman peaks. The results are compared with those obtained from the measure
of the linewidths in the X-ray diffraction spectra. Nanocrystals with a mean size in the range 4–20 nm are obtained
by thermal annealing in a corresponding range of 700–1300◦C
Raman study of gallium arsenide thin films.
No full textThe influence of deposition parameters on the structure of the gallium arsenide thin films was investigate Raman scattering. The study was based on the analysis of the first-order Raman spectra which allows for a differentiation between the amorphous component and crystallites of various sizes. The amorphous and crystalline volume fractions were calculated from the integrated intensities of the deconvoluted peaks. It was demonstrated that a transition occurs from mu-GaAs to a-GaAs for particular plasma conditions and substrate temperature. As a function of the deposition parameters the entire range from mostly microcrystalline to completely amorphous films can be obtained. These properties were consistent with the results obtained on the same samples by transmission high-energy electron diffraction and conventional transmission electron microscopy
Preparation and characterization of polycarbonate/multiwalled carbon nanotube nanocomposites
No full text
Raman scattering fron acoustical modes of silicon nanoparticles embedded in silica matrix
No full textDevelopment of social skills of 3-4-year-old children in a preschool educational institution.
No full textKvalifikācijas darba tēma – 3-4 gadus vecu bērnu sociālo prasmju attīstīšana pirmsskolas izglītības iestādē. Darba autors – Ivanda Lavrinoviča. Darba mērķis ir noteikt, kā rotaļnodarbības palīdz attīstīt sociālās prasmes 3 – 4 gadīgiem bērniem pirmsskolā. Kvalifikācijas darbs sastāv no 2 daļām. Pirmajā daļā aplūkots un pētīts sociālo prasmju teorētiskais apraksts, 3 - 4 gadīgu bērnu attīstības raksturojums pētāmās problēmas kontekstā, kā arī rotaļnodarbību teorētiskais aspekts un rotaļnodarbību nozīme sociālo prasmju attīstības veicināšanā. Otrajā, empīriskajā daļā, veikts pētījums par sociālo prasmju izpausmēm 3 - 4 gadīgiem bērniem un rotaļnodarbību nozīme sociālo prasmju attīstīšanai. Pētījums veikts, izmantojot pedagoģisko novērošanu un praktisko izmēģinājumdarbību, 15 pirmsskolas izglītības iestādes bērniem vecumā no 3 – 4 gadiem. Pētījuma rezultātā tika secināts, ka ikviena rotaļnodarbība attīsta bērnu sociālās prasmes, jo ikvienā rotaļnodarbībā ir integrēta kāda sociālās prasmes. Darbs sastāv no 27 lapas pusēm, 2 attēliem, 4 tabulām, 2 pielikumiem, izmantoti 18 literatūras avoti, izdarīti 5 secinājumi. Atslēgas vārdi: sociālās prasmes, socializācija, sociālo prasmju attīstība, sociālo prasmju nozīme. Ierobežotā darba apjoma un laika dēļ pētījuma bāze ir – 15 bērni, tāpēc darbs var kalpot par pamatu turpmāka pētījumu veikšanai, iekļaujot pētījumā vairāk bērnu un veicot pētījumu ilgākā laika periodā, kas pētījuma rezultātus padarītu pamatotākus.The subject of the qualification work - development of social skills of 3-4-year-old children in a preschool educational institution. Author - Ivana Lavrinoviča. The aim of the work - is to determine how play lessons help to develop social skills in 3–4-year-old children in preschool. The qualification work consists of 2 parts. The first part examines and studies the theoretical description of social skills, the characteristics of the development of 3–4-year-old children in the context of the researched problem, as well as the theoretical aspect of play lessons and the importance of play lessons in promoting the development of social skills. In the second, empirical part, a study was conducted on the manifestations of social skills in 3–4-year-old children and the importance of play lessons for the development of social skills. The research was conducted using pedagogical observation and practical trial activities in 15 preschool educational institutions for children aged 3-4 years. As a result of the study, it was concluded that every play lesson develops children's social skills, because every play lesson integrates some social skills. The work consists of 27 pages, 2 pictures, 4 tables, 2 appendices, 18 literary sources are used, 5 conclusions are drawn. Keywords: social skills, socialization, development of social skills, importance of social skills. Due to the limited size and time of work, the study base is limited to 15 children, so the work can serve as a basis for further studies, including more children in the study and conducting a study over a longer period that would make the results more reasonable
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