Submitted by Rosivalda Pereira (mrs.pereira@ufma.br) on 2017-05-05T21:10:26Z No. of bitstreams: 1 MariaQueiroz.pdf: 2090669 bytes, checksum: c6260460d0519cea58bbd10d9c9f8334 (MD5) / Made available in DSpace on 2017-05-05T21:10:26Z (GMT). No. of bitstreams: 1 MariaQueiroz.pdf: 2090669 bytes, checksum: c6260460d0519cea58bbd10d9c9f8334 (MD5) Previous issue date: 2016-11-25 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Fundação de Amparo à Pesquisa e ao Desenvolvimento Científico e Tecnológico do Maranhão (FAPEMA) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPQ) / The Sm2O3-doped calcium borotellurite glasses studied in this research were synthesized by melt-quenching method, characterized according to their structural, thermal, spectroscopic and optical properties and analyzed as a function of TeO2 concentration. The analysis of the properties was performed by the following characterizations: X-ray diffraction, volumetric density, Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), optical absorption spectroscopy, differential thermal analysis (DTA), specific heat, refractive index, photoluminescence and lifetime decay. In addition, molar volume, optical band gap, electronic polarizability, number of ions per cubic centimeter, interionic distance, chromaticity, DE/DM ratio and orange/red ratio values were also evaluated. The results have showed that the increase of TeO2 concentration increased the volumetric density (~41%). The X-Ray spectra confirmed the amorphous nature of the samples. The Raman and FTIR results indicated the presence of the following structures: TeO3, TeO3+1, TeO4, BO3 and BO4. Moreover, the increase of nonbridging oxygen was confirmed. The increase of the TeO2 concentration decreased the specific heat and the glass transition temperature of the samples. The refractive index increased, due to an increase of density and electronic polarizability. The insertion of the doping agent was confirmed by the optical absorption spectra, which presented peaks characteristic of Sm3+ ions (most intense peak at ~402 nm). The emission intensity of the Sm3+ ions decreased (~2.2%) with the increase of TeO2 concentration. The chromaticity of the samples analyzed by CIE diagram showed small variation at x and y positions. However, under visual inspection, the variation of the emitted color was not observed. The emission intensity as a function of temperature, showed a decrease for all samples. The lifetime for the emission at ~598 nm also presented a reduction with the increase of TeO2 content, due to the increase of NBOs. Therefore, the synthesized materials present good properties, and finds their applications as potential candidate for optical devices, such as solid state lasers, Light-emitting diodes (LEDs), among others. / Os vidros cálcio boroteluretos dopados com Sm2O3 estudados neste trabalho foram sintetizados pelo método de fusão/resfriamento e caracterizados quanto às suas propriedades estruturais, térmicas, espectroscópicas e ópticas. Essas propriedades foram analisadas em função da concentração de TeO2. A análise das propriedades foi feita por meio das seguintes caracterizações: densidade volumétrica (método de Arquimedes), difração de raios-X, espectroscopia Raman, espectroscopia no infravermelho via transformada de Fourier (FTIR), espectroscopia de absorção óptica, análise térmica diferencial (DTA), calor específico, índice de refração, fotoluminescência e tempo de vida, além do cálculo dos valores de energia de band gap óptico, polarizabilidade eletrônica, número de íons por centímetro cúbico, distância interiônica, cromaticidade, razão dipolo elétrico/dipolo magnético (DE/DM) e razão laranja/vermelho. A densidade e o volume molar tiveram um aumento simultâneo devido ao aumento da massa molar do vidro. Os espectros de difratometria de raios-X mostraram que todas as amostras são amorfas e sem a presença de cristalitos. A temperatura de transição vítrea e o calor específico das amostras diminuíram com o aumento da concentração de TeO2. Os resultados de Raman e FTIR mostraram a presença das estruturas TeO3, TeO3+1, TeO4, BO3 e BO4.O índice de refração também teve um aumento, devido ao aumento da densidade e da polarizabilidade eletrônica. Por meio dos espectros de absorção óptica foi comprovada a inserção do dopante nas amostras, pois apresentam picos de absorção característicos do Sm3+, sendo o pico mais intenso em ~402 nm. A intensidade de emissão teve uma redução (~2,2%) com o aumento de TeO2. O tempo de vida para a emissão em ~598 nm também teve uma redução com o aumento da concentração de TeO2, devido ao aumento de oxigênios não-ligados (NBOs). A cromaticidade das amostras analisadas pelo diagrama CIE, mostrou uma pequena variação nas posições x e y, no entanto, sob inspeção visual não houve variação da cor emitida. Os resultados mostraram que o material sintetizado apresenta boas propriedades, com potencial para ser aplicado em dispositivos fotônicos, como lasers de estado sólido, lasers emissores de luz (LEDs), dentre outros.

Background. China is regulating the import, export, sale, and use of encryption technology in China. If any foreign company wants to develop or release a product in China, they need to report their use of any encryption technology to the Office of State Commercial Cryptography Administration (OSCCA) to gain approval. SM2, SM3, and SM4 are cryptographic standards published by OSCCA and are authorized to be used in China. To comply with Chinese cryptography laws organizations and companies may have to replace standard cryptographic algorithms in their systems with Chinese cryptographic algorithms, such as SM2, SM3, and SM4. It is important to know beforehand how the replacement of algorithms will impact performance to determine future system costs. Objectives. Perform a theoretical study and performance comparison of the standard cryptographic algorithms and Chinese Cryptographic algorithms. The standard cryptographic algorithms studied are RSA, ECDSA, SHA-256, and AES-128, and the Chinese cryptographic algorithms studied are SM2, SM3, and SM4. Methods. A literature analysis was conducted to gain knowledge and collect information about the selected cryptographic algorithms in order to make a theoretical comparison of the algorithms. An experiment was conducted to get measurements of how the algorithms perform and to be able to rate them. Results. The literature analysis provides a comparison that identifies design similarities and differences between the algorithms. The controlled experiment provides measurements of the metrics of the algorithms mentioned in objectives. Conclusions. The conclusions are that the digital signature algorithms SM2 and ECDSA have similar design and also similar performance. SM2 and RSA have fundamentally different designs, and SM2 performs better than RSA when generating keys and signatures. When verifying signatures, RSA shows comparable performance in some cases and worse performance in other cases. Hash algorithms SM3 and SHA-256 have many design similarities, but SHA-256 performs slightly better than SM3. AES-128 and SM4 have many similarities but also a few differences. In the controlled experiment, AES-128 outperforms SM4 with a significant margin. / Bakgrund. Kina reglerar import, export, försäljning och användning av krypteringsteknologi i Kina. Om ett utländskt företag vill utveckla eller släppa en produkt i Kina måste de rapportera sin användning av krypteringsteknologi till Office of State Commercial Cryptography Administration (OSCCA) för godkännande. SM2, SM3 och SM4 är kryptografiska standarder som lagligt får används i Kina. Organisationer och företag kan behöva byta ut krypteringsalgoritmerna i sina system till kinesiska krypteringsalgoritmer för att uppfylla kraven för de kinesiska lagarna. Det är därför viktigt att i förväg veta hur ersättningen av algoritmer kommer att påverka prestandan för att utvärdera framtida kostnader för systemet. Syfte. Genomföra en teoretisk studie och prestanda jämförelse av standard krypteringsalgoritmer och kinesiska krypteringsalgoritmer. De standard krypteringsalgoritmerna är RSA, ECDSA, SHA-256 och AES-128. De kinesiska krypteringsalgoritmerna är SM2, SM3 och SM4. Metod. En litteraturanalys har genomförts för att få en bättre förståelse av de valda algoritmerna. Ett experiment har genomförts för att samla mätvärden av de bestämda parametrarna och för att sedan kunna ranka mätvärdena. Resultat. Litteraturanalysen gav en jämförelse som identifierar likheter och skillnader mellan algoritmerna. Det kontrollerade experimentet gav mätvärden av parametrarna för algoritmerna nämnda i syftet. Slutsatser. Slutsatserna är att de digitala signatur-algoritmerna SM2 och ECDSA har liknade design och också liknade prestanda. SM2 och RSA har fundamentala skillnader i deras design, och SM2 har bättre prestanda vid nyckelgenerering samt signaturgenerering. Vid verifiering av signaturer så visar RSA likvärdig prestanda i vissa fall och sämre prestanda i andra fall. Hashfunktionerna SM3 och SHA-256 har också många likheter i sin design, men SHA-256 presterar lite bättre än SM3. AES-128 och SM3 har många design likheter men också några skillnader. I det kontrollerade experimentet så presterar AES-128 bättre än SM4 med stor marginal.