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REALIDADE VIRTUAL E GEOGRAFIA:O CASO DO GOOGLE CARDBOARD GLASSES PARA O ENSINO
摘要： A realidade virtual torna-se mais presente na vida das pessoas e suas aplica??es tem conquistado distintos segmentos, a exemplo do ensino em sala de aula. Essa inova??o tecnológica tem alto custo de implementa??o, carecendo de iniciativas de baixo custo para ampliar o acesso a um maior número de pessoas. O objetivo deste estudo é analisar a viabilidade do uso da tecnologia de realidade virtual como ferramenta didática para o ensino de Geografia. Como metodologia foi utilizado o Google Cardboard Glasses, junto a um smarthphone e o aplicativo CardBoard disponível na GooglePlaystore, vídeos 360o no YouTube e o Google StreetView. Dentre os resultados encontrados destacam-se uma maior imers?o do Google Earth 3D, disponível no CardBoard, em um ambiente tridimensional simulado da superfície terrestre; uma grande quantidade de lugares disponíveis no Google StreetView possibilitando à realiza??o de “trabalhos de campos virtuais”; e a possibilidade de, através dos vídeo 360o, inserir o aluno em fen?menos que n?o poderiam ser observados por fotos ou ambientes simulados até ent?o estáticos do Google Earth 3D. Foi possível perceber um enorme potencial da realidade virtual no ensino de Geografia, com alternativas de baixo custo permitindo ao professor e aos alunos, processos de ensino mais dinamicos e atrativos.
关键词： Ensino de geografia,Realidade virtual,Google Cardboard Glasses
更新于2025-09-04 15:30:14
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Optical characterization of nanostructured Ge1???xSnxSe2.5 (x?=?0, 0.3, 0.5) films
摘要： The paper reports the optical properties of thin films of nanostructured Ge1 ? xSnxSe2.5 (x = 0, 0.3, 0.5) glassy alloys. The glassy alloys of Ge1 ? xSnxSe2.5 (x = 0, 0.3, 0.5) were prepared using melt quenching method. Thin films of nanostructured Ge1 ? xSnxSe2.5 (x = 0, 0.3, 0.5) glassy alloys were prepared using physical vapor deposition method. The films were characterized using XRD, EDX and TEM, which confirmed the amorphous nature, composition and formation of nanorods in the samples. Absorption and transmission spectra of thin films were recorded in the spectral range 400–2500 nm to obtain energy band gap, refractive index, extinction coefficient, dielectric constant etc. Results show that refractive index increases while band gap decreases on increase of Sn content in the Ge–Se system. This is due to the increase in density of defect states within band gap. The values of Urbach energy support the obtained results.
关键词： Thin films,Nanostructured glasses,Optical properties,Band gap
更新于2025-09-04 15:30:14
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Effect of Er3+ on NaSrB glass: thermoluminescence and structural analysis
摘要： The present work reports the investigations on Er3+-doped sodium–strontium–borate glasses for their structural, optical and thermoluminescence (TL) properties. While the amorphous nature of the prepared glasses is confirmed by the powdered X-ray diffraction (XRD), some interesting features were found in the structure and Fourier-transform infrared (FTIR) studies such as the nanocrystallization and the presence of BO3 and BO4 structural units. Some physical parameters such as ion concentration, polaron radius, inter-nuclear distance, and field strength are calculated and analyzed. Optical band gap was found to be sensitive to the concentration of the dopants. TL glow curve exhibits a single peak but it shifts with variation in concentration of Er2O3. Calculation of kinetic parameters show that the prepared glasses exhibit second-order kinetics. The effective atomic number (Zeff) of prepared glasses is also calculated which indicates their suitability for application in radiation dosimetry.
关键词： thermoluminescence,sodium–strontium–borate glasses,optical properties,radiation dosimetry,Er3+-doped,structural analysis
更新于2025-09-04 15:30:14
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Stuctural, optical and radiation shielding properties of zinc boro-tellurite alumina glasses
摘要： In this work, boro-telluride glasses with additional zinc, aluminum, and alkali–alkaline modifiers have been synthesized using the melt-quenching–annealing method. Six glasses were fabricated with composition of [(60 ? x)B2O3–(10 + x)TeO2–10ZnO–10Al2O3–5Li2O–5MgO] all in mol% and x varied from 0, 10, 20, 30, 40 and 50. The aim of this work is to understand the effect of changing the main glass former from B2O3 → TeO2, to obtain new optical materials. To confirm the amorphous nature of these six glasses, X-ray diffraction was characterized for all six glasses from 10° to 80°. Optical absorption with wavelength range 200–800 nm in room temperature was measured, and the optical absorption coefficient α(λ) calculated to obtain the cutoff wavelength. In addition, gamma photons shielding features of the prepared K1–K6 glasses were evaluated by means of some essential parameters such as mass attenuation coefficients (μ/ρ) and effective atomic number (Zeff) at five energies between 0.356 and 1.33 MeV. No significant difference between the theoretical and simulation μ/ρ values was found. The effective atomic number results indiacte that as the TeO2 content increases, the photons’ attenuation increases. The number of interactions of gamma photons with K6 sample (which contains the maximum amount of TeO2) is relatively high (in comparison to the rest of the samples), which results in more attenuation and thus better shielding features for K6.
关键词： Effective atomic number,Mass attenuation coefficients,Gamma photons shielding,Boro-tellurite glasses,Optical materials
更新于2025-09-04 15:30:14
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PbO–Bi2O3–Ga2O3–BaO glass nanocomposites as promising materials for elastoopticity
摘要： A new type of elastooptic materials based on PbO–Bi2O3–Ga2O3–BaO glasses have been fabricated. The studies of piezooptical effect at 1150 nm He-Ne laser wavelength have shown that the elastoopticity is crucially dependent on the nanoparticle (NP) sizes. The optimal effect exists at NP concentration equal to about 25%. The principal role of the interfaces between the glass nanoparticles and photopolymer PVA matrices is found. The piezooptic effect has shown sensitivity to the temperature also. The obtained values of piezooptical coefficients are compared with other glasses.
关键词： piezooptics,oxide glasses,polymer nanocomposites
更新于2025-09-04 15:30:14
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Red-emission properties and crystallization behavior in Eu2O3-TeO2 glasses
摘要： Transparent glass of xEu2O3-(100-x)TeO2 binary system is obtained by using the melt-quenching method and especially studied for x = 5 in xEu2O3-(100-x)TeO2 composition. Optical properties such as transmission, excitation, and emission spectra of Eu2O3-TeO2 glass-ceramics are studied and carefully compared for the samples heated at di?erent temperatures. The one step heat-treatment a?ects the crystallinities as well as phase formation and yields cubic [Eu2Te6O15], orthorhombic [TeO2], and tetragonal [TeO2] phases depending on the heat treating temperature. Glass-ceramics of Eu3+-doped tetragonal [TeO2] shows stronger emission intensity at wavelength of 613 nm with an excitation wavelength of 394 nm compared with that from cubic [Eu2Te6O15] or Eu3+-doped orthorhombic [TeO2]. Enhancement of emission intensity in Eu3+-doped tetragonal [TeO2] is related to the local environment of Eu3+ ions substituted in tetragonal TeO2 lattice.
关键词： Tellurite glasses,Glass-ceramics,Optical property,Eu2Te6O15 crystal
更新于2025-09-04 15:30:14
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Effect of Tm3+ Sensitization to Ho3+ Doped GeO2-B2O3-BaF2-Al2O3-ZnO2-Na2O Glass on Spectral Properties
摘要： A series of Tm3+/Ho3+ sensitized 65GeO2-7BaF2-10B2O3-4Al2O3-4ZnO2-10Na2O glass samples were synthesized by using high temperature melting method. The spectral properties were systematically studied when Ho3+ concentration was 0.1, 0.3, 0.5 mol % and Tm2O3 changed from 0.3 to 2.5 mol %. Differential thermal analysis showed that ?T was higher than 190 oC, which illustrated this kind of matrix glass have better thermal stability. The absorption cross section peak height, free energy of Ho3+ from 5I8 to 5I7 and emission cross section were calculated according to Mc-Cumber theory. Under the excitation of 808 nm laser diode, fluorescence intensity at 1954 nm reached the highest value when the concentration of Ho3+ was 0.1 mol % and Tm3+ was 0.7 mol %. However the fluorescence intensity reduced greatly when Ho3+ concentration was 0.5 mol % and Tm3+ exceeded 1.5 mol %. The sensitized function and influence of different Tm3+/Ho3+ doped ion ratios on the spectral properties was studied.
关键词： Glasses,Growth from high temperature solutions,Rare earth compounds,Adsorption
更新于2025-09-04 15:30:14
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[IEEE 2018 IEEE 7th Global Conference on Consumer Electronics (GCCE) - Nara, Japan (2018.10.9-2018.10.12)] 2018 IEEE 7th Global Conference on Consumer Electronics (GCCE) - Proposal and Implementation of Personal Authentication Method by Visual Secret Sharing Scheme Using Smart Glasses
摘要： Personal authentication by password only is major, however it has some security risks. As a new approach to personal authentication, several methods by Visual Secret Sharing Scheme have been proposed. We propose a personal authentication method by Visual Secret Sharing Scheme using smart glasses, that improve the methods in previous studies. The method is secure against shoulder surfing, eavesdropping, and leakage of information from the server. Moreover, in the method, an encrypted one-time password is decrypted automatically. Furthermore, by it is conducting implementations and evaluation experiments, found that the method has high convenience in operating time, operability, and ease of learning operation.
关键词： smart glasses,security,Visual Secret Sharing Scheme,one-time password,personal authentication
更新于2025-09-04 15:30:14
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Synthesis of silver nanoparticles from bottom up approach on borophosphate glass and their applications as SERS, antibacterial and glass-based catalyst
摘要： In this paper, we report a facile, low cost synthesis and characterization of silver nanoparticles (AgNPs) on borophosphate glass by a two-step process involving a melting quenching technique and a post-annealing method. The structural, optical properties and several applications of silver-doped borophosphate glasses as a function of Al2O3 concentration are reported here. Micro Raman and infrared spectroscopies revealed that the addition of aluminium ions leads to depolymerization and the formation of phosphate-aluminium structures. Moreover, the addition of Al2O3 increases the glass transition temperature, improve the chemical stability, and the AgNPs remain ?rmly grafted (i.e., not released) when the glass surface is exposed to water. The presence of silver ions and metallic silver on glass surface was con?rmed by the X-ray photoelectron spectroscopy (XPS) and X-ray powder di?raction (XRD), respectively. The fabricated AgNPs have many advantages, such as low growth temperature and good uniform nanoparticle clusters over large areas, size-controlled, and easy to fabricate. Finally, the silver-doped glasses have proved to be an ideal substrate for highly e?cient SERS applications, antibacterial materials and great potential in catalysts.
关键词： Antimicrobial glass,Glass catalyst,Borophosphate glasses,SERS substrates,Silver nanoparticles
更新于2025-09-04 15:30:14
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Oxyfluoro-zinc-tellurite glasses – Part I: Predicting the elastic properties and glass transition temperature under the substitution of AlF3 by ZnO
摘要： An extensive study has been carried out to predict the elastic properties and glass transition temperature of oxyfluoro-zinc-tellurite (10-x)AlF3-xZnO-90TeO2 (1 ≤ x ≤ 9), (30-x)AlF3-xZnO-70TeO2 (5 ≤ x ≤ 25), (35-x)AlF3-xZnO-65TeO2 (10 ≤ x ≤ 30) and (40-x)AlF3-xZnO-60TeO2 (15 ≤ x ≤ 35) glass systems, for the first time. Changes in the elastic moduli, Poisson’s ratio and glass transition temperature due to the substitution of AlF3 by ZnO have been discussed in terms of molar volume, fractal bond connectivity, packing density and dissociation energy per unit volume of the glass. The correlation between theoretically calculated and experimentally measured elastic moduli and Poisson's ratio has also been studied on the basis of Makishima-Mackenzie’s theory and Rocherulle et al. model. The composition dependence of fractal bond connectivity suggested that the studied oxyfluoro-zinc-tellurite glasses have an intermediate dimensionality between three- and two-dimensional structures. Both AlF3 and ZnO are incorporated into the tellurite network as network modifiers. This results is the conversion of TeO4 trigonal bipyramids into TeO3+1 polyhedral and then to TeO3 trigonal pyramids through breaking of TeeOeTe linkages and creation of non-bridging oxygen atoms. In addition to this, both Makishima-Mackenzie's theory and Rocherulle et al. model appear to be applicable for all the investigated glass systems. The agreement between theoretical and experimental values of elastic moduli and Poisson's ratio is excellent for majority of the samples.
关键词： Rocherulle et al. model,Elastic properties,Makishima–Mackenzie’s theory,Oxyfluorotellurite glasses
更新于2025-09-04 15:30:14