{"title":"The Nanostructure Zeolites MFI-Type ZSM5","authors":"L. Zoubida, Belarbi Hichem","doi":"10.5772/INTECHOPEN.77020","DOIUrl":"https://doi.org/10.5772/INTECHOPEN.77020","url":null,"abstract":"The development of new porous solids begins to provide effective and original solutions to the problems of pollution and sustainable development, and the challenge is to discover new performance of these materials. Among these materials are zeolites; however, one type has retained the attention since its discovery in 1972; this is zeolite-type ZSM-5, because of their particular properties in many industrial processes. These porous solids are characterized on the atomic scale by the existence of pores, distributed regularly in the matter and are likely to accommodate in their structures, gases, liquids, and solids for trap or temporarily store them. Only the average porosity of these zeolites constitutes an obstacle to the catalysis of cumbersome molecules that are well branched. To deflect this inaccessibility factor and trying to find a solution to this steric hindrance, the attention of the researchers was focused on using the surface properties of ZSM-5. It is well known that the efficiency and selectivity of a porous catalyst depends on its textural and structural characteristics and more precisely on the number of locations active on the external surface and the number of locations accessible through the porous system. The nanocrystallinity in the field of zeolites can be defined as a situation in which the physicochemical properties are largely determined by a larger number of atoms in the outer limit of crystallite. In this chapter, the work of several researchers who synthesized the ZSM5 in the field of nanostructures is presented. We find that, despite the different methods of synthesis, however, the field of nanostructures ZSM5 has been achieved. Certain parameters such as the concentration of mineral agent, the concentration of the structuring agent, and the duration of aging have a direct influence on the crystal size of the zeolites obtained. Different characterizations were used to identify the purity and size of the nanocrystals ZSM5.","PeriodicalId":108831,"journal":{"name":"Nanocrystals and Nanostructures","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122942511","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Nanograin Formation within Shear Bands in Cold-Rolled Titanium","authors":"Dengke Yang, Huimin Yang","doi":"10.5772/INTECHOPEN.76969","DOIUrl":"https://doi.org/10.5772/INTECHOPEN.76969","url":null,"abstract":"Microstructure evolution within the shear localization areas in a commercial titanium plate subjected to cold rolling was systematically investigated. A shear band with a width of approximately 25 μm was formed. The microstructure inside the shear band was mainly equiaxed nanograins with an average size of 70 nm. Transmission electron microscopy (TEM) observations revealed that the grain refinement inside the shear band was completely via a shear deformation-induced splitting and breakdown twin lamella process, instead of a nucleation and growth of new grains. The shear localization starts with the formation and multiplication of mechanical twins, which leads to the development of a twin/matrix lamellar structure aligned along the shear direction. The twin/ matrix lamellae subsequently undergo gradual splitting and transverse breakdown, giv ing rise to fine elongated subgrains. The continuing lath breakdown, in combination with grain lateral sliding and lattice rotations, ultimately leads to the formation of a mix of roughly equiaxed, nanosized (sub)grains within the center of macroscopic shear band at large strains.","PeriodicalId":108831,"journal":{"name":"Nanocrystals and Nanostructures","volume":"244 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115959529","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abel Roman, José Alberto Luna López, Álvaro DavidHernández de la Luz, E. G. Barojas, A. B. Lara, D. E. V. Valerdi, Miguel Ángel DomínguezJimenez
{"title":"Colloidal Solutions with Silicon Nanocrystals: Structural and Optical Properties","authors":"Abel Roman, José Alberto Luna López, Álvaro DavidHernández de la Luz, E. G. Barojas, A. B. Lara, D. E. V. Valerdi, Miguel Ángel DomínguezJimenez","doi":"10.5772/INTECHOPEN.74429","DOIUrl":"https://doi.org/10.5772/INTECHOPEN.74429","url":null,"abstract":"In this work, colloidal solutions with silicon nanoparticles using different solvents were synthetized. Structural, morphological and optical characterizations were realized, and these were studied. X-ray diffraction (XRD) was used to measure the diffractograms of the colloidal solutions, which are composed of silicon nanocrystals (Si-ncs), with an average size of approximately 3 nm, and a preferential crystalline orientation (311). Atomic force microscopy (AFM) images show that the morphology of silicon nanoparticles (Si-nps) is agglomerated in a big amount, which is corroborated by means of the roughness. On the other hand, high resolution transmission electronic microscopy (HRTEM) images show on average size of the Si-nc ranging from 1.5 to 10 nm, which depends on the solvent used. Also, different preferential crystalline orientations of the Si-nc such as (311), (220) and (111) were obtained. A correlation between the optical and structural properties was realized in colloidal solutions with silicon nanoparticles and different solvents.","PeriodicalId":108831,"journal":{"name":"Nanocrystals and Nanostructures","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130811174","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Coyopol-Solís, T. Diaz-Becerril, G. G. Salgado, S. A. Cabanas-Tay, L. Palacios-Huerta, A. Morales-Sánchez
{"title":"Synthesis and Luminescent Properties of Silicon Nanocrystals","authors":"A. Coyopol-Solís, T. Diaz-Becerril, G. G. Salgado, S. A. Cabanas-Tay, L. Palacios-Huerta, A. Morales-Sánchez","doi":"10.5772/INTECHOPEN.74286","DOIUrl":"https://doi.org/10.5772/INTECHOPEN.74286","url":null,"abstract":"Nowadays, study of silicon-based visible light-emitting devices has increased due to large-scale microelectronic integration. Since then different physical and chemical processes have been performed to convert bulk silicon (Si) into a light-emitting material. From discovery of Photoluminescence (PL) in porous Silicon by Canham, a new field of research was opened in optical properties of the Si nanocrystals (Si-NCs) embedded in a dielectric matrix, such as SRO (silicon-rich oxide) and SRN (silicon-rich nitride). In this respect, SRO films obtained by sputtering technique have proved to be an option for light-emitting capacitors (LECs). For the synthesis of SRO films, growth parameters should be considered; Si-excess, growth temperature and annealing temperature. Such parameters affect generation of radiative defects, distribution of Si-NCs and luminescent properties. In this chapter, we report synthesis, structural and luminescent properties of SRO monolayers and SRO/SiO2 multilayers (MLs) obtained by sputtering technique modifying Si-excess, thickness and thermal treatments.","PeriodicalId":108831,"journal":{"name":"Nanocrystals and Nanostructures","volume":"69 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115159258","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Twin Deformation Mechanisms in Nanocrystalline and Ultrafine-Grained Materials","authors":"N. Skiba","doi":"10.5772/INTECHOPEN.74978","DOIUrl":"https://doi.org/10.5772/INTECHOPEN.74978","url":null,"abstract":"The review of the theoretical models, which describes mechanisms of deformation twin- ning in nanocrystalline and ultrafine-grained materials, is presented. Realization of special mechanisms of nanoscale deformation twin generation at locally distorted grain bound- aries (GBs) in nanocrystalline and ultrafine-grained materials is observed. In particular, the micromechanisms of deformation twin formation occur through (1) the consequent emission of partial dislocations from GBs; (2) the cooperative emission of partial dislocations from GBs; and (3) the generation of multiplane nanoscale shear at GBs. The energy and stress characteristics of the deformation nanotwin generation at GBs in nanocrystalline and ultrafine-grained materials are calculated and analyzed. Competition between the twin generation mechanisms in nanocrystalline and ultrafine-grained materials is discussed.","PeriodicalId":108831,"journal":{"name":"Nanocrystals and Nanostructures","volume":"81 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126757420","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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