Atomic Structure
Mostrando 1-12 de 567 artigos, teses e dissertações.
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1. Study of rhombohedral tricalcium phosphate in hexagonal crystal structure family on the sample prepared by the sol-gel route and the effect of calcination temperature
Abstract The effect of the calcination temperature at 800 and 1000 °C on the stable formation of the tricalcium phosphate with rhombohedral structure in the system of the hexagonal crystal family was determined, while its precursor was made from limestone obtained from nature in the Lumajang district, Indonesia. The rhombohedral tricalcium phosphate samples
Cerâmica. Publicado em: 2023
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2. Silicon carbide hollow fiber membranes developed for the textile industry wastewater treatment
Abstract In order to reduce the impacts of the industrial effluent on the environment, silicon carbide hollow fiber membranes were prepared by the precipitation-immersion technique and sintered at 1450 and 1500 °C. The membranes were characterized by X-ray diffraction, their surface structure was characterized by scanning electron microscopy and atomic forc
Cerâmica. Publicado em: 2021-06
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3. EVALUATION OF THE CHEMICAL COMPOSITION AND STRUCTURE OF ASPHALTENES FROM THREE OFFSHORE BRAZILIAN BIODEGRADED HEAVY OILS
Asphaltenes fractions were extracted and purified from three heavy Brazilian oils. Their mass compositions of C, H, N, Ni and V were obtained from elemental analysis and S and O atomic percentages from EDS. The H/C ratios showed high degree of unsaturation, while the O atomic percentages indicated more pronounced biodegradation effects on two samples. Quanti
Quím. Nova. Publicado em: 2021-04
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4. ORBITALS IN GENERAL CHEMISTRY, PART II: MATHEMATICAL REALITIES
In Part II of a three-part series, we discuss two factors absent from textbooks of general chemistry that are important in a discussion of teaching orbitals. First, atomic orbitals are shown systematically to comprise algebraic formulae in coordinates of not one but four sets (spherical polar, paraboloidal, ellipsoidal, spheroconical coordinates). Each formu
Quím. Nova. Publicado em: 2021-03
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5. HPV infection - Screening, diagnosis and management of HPV-induced lesions
In Part II of a three-part series, we discuss two factors absent from textbooks of general chemistry that are important in a discussion of teaching orbitals. First, atomic orbitals are shown systematically to comprise algebraic formulae in coordinates of not one but four sets (spherical polar, paraboloidal, ellipsoidal, spheroconical coordinates). Each formu
Rev. Bras. Ginecol. Obstet.. Publicado em: 2021-03
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6. Hybrid Hydrogels Based on Polyethylene Glycol Bioconjugated with Silylated-Amyloidogenic Peptides
Hybrid-peptide hydrogel arrangements are a promising alternative to obtaining biocompatible structures at the nanoscopic scale. In this work, a new class of hybrid hydrogels was obtained through the sol-gel process based on the reaction between an amyloid-like octapeptide sequence [RF]4 (where R = arginine and F = phenylalanine) covalently bonded with glycin
J. Braz. Chem. Soc.. Publicado em: 2020-11
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7. VIBRATIONAL SPECTROSCOPIC INVESTIGATION AND MOLECULAR STRUCTURE OF A 5α-REDUCTASE INHIBITOR: FINASTERIDE
By way of Density Functional Theory (DFT)-based computational methods with commercially available software, the computational work of which about the molecular properties, the vibrational modes and vibrational frequencies of finasteride were accomplished for the first time. In order to gain a deeper and more thorough understanding of the molecular structure
Quím. Nova. Publicado em: 2020-05
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8. Pesquisas em políticas de comunicação em contextos de crise
By way of Density Functional Theory (DFT)-based computational methods with commercially available software, the computational work of which about the molecular properties, the vibrational modes and vibrational frequencies of finasteride were accomplished for the first time. In order to gain a deeper and more thorough understanding of the molecular structure
Intercom, Rev. Bras. Ciênc. Comun.. Publicado em: 2020-05
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9. Caracterização de termistores automotivos do tipo NTC
RESUMO Os termistores automotivos são eletrocerâmicas com características sensoras alojadas em estojos metálicos fixadas no radiador, que têm como função controlar a temperatura da água de resfriamento do motor. O objetivo deste trabalho foi caracterizar dois termistores comerciais aplicados em veículos automotores. Os termistores caracterizados for
Matéria (Rio J.). Publicado em: 25/11/2019
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10. HYBRID ATOMIC ORBITALS IN ORGANIC CHEMISTRY. PART 2: CRITIQUE OF PRACTICAL ASPECTS
The importance of hybrid atomic orbitals, in both general and organic chemistry, is reviewed. Every contemporary textbook of organic chemistry introduces the directed-valence (e.g. sp3, sp2, sp) model, but the suitability of these hybrid orbitals for use in the teaching of molecular structure has been increasingly questioned. Based on a critical survey of th
Quím. Nova. Publicado em: 26/08/2019
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11. Palladium Nanoparticles Supported on β-cyclodextrin Functionalised Poly(amido amine)s and their Application in Suzuki-Miyaura Cross-Coupling Reactions
Herein, the synthesis, characterization and catalytic application of an organic-inorganic, palladium (Pd)-containing hybrid material, poly(amidoamine)-cyclodextrin (Pd@PAAs-CD), is reported as an efficient catalyst for Suzuki-Miyaura coupling reactions. The structure of Pd@PAAs-CD was confirmed by Fourier transform infrared spectroscopy (FTIR), transmission
J. Braz. Chem. Soc.. Publicado em: 12/08/2019
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12. Obtenção de hydrochar a partir de carbonização hidrotérmica de cascas do fruto de Magonia pubescens A. St. Hil. Sapindaceae: Caracterização e avaliação em processo de adsorção
RESUMO A Carbonização hidrotermal (HTC) de cascas do fruto de Magonia pubescens A. St. Hil. Sapindaceae (Tingui do cerrado) é apresentada como uma proposta inédita na produção de hydrochars a partir de precursores de espécies do Cerrado Brasileiro, onde se verificou a influência da temperatura nas propriedades dos materiais obtidos. Os hyrochar obtid
Matéria (Rio J.). Publicado em: 10/06/2019