Listar Química por título
Mostrando ítems 170-189 de 360
-
Focos de Innovación 2024-2025
(2024-02-21)Es evidente que las transformaciones ambientales, sociales y económicas, que son necesarias para el desarrollo a nivel global, dependen de las soluciones novedosas que la ciencia, la tecnología y la innovación puedan ... -
Fotorreducción de dióxido de carbono usando TiO2 sensibilizado con trímeros de Co y Cu en medio acuoso
(2021-01-31)En la presente investigación, se evaluó el desempeño de dos fotocatalizadores de dióxido de titanio, uno sensibilizado con un trímero de cobre (Cu3(dpa)4Cl2) (dpa = 2,2 ́-dipiridilamina) y el otro con un trímero de cobalto ... -
From Ideality to Simplicity: A Robust and Affordable Hydrogen Reference Electrode
(2020-02-01)In electrochemistry, the concept of a reference electrode is fundamental. Introductory courses might mention the standard hydrogen electrode (SHE), its working principle, and its theoretical design; however, chances are ... -
Fundamentos de Química Orgánica
(1985)Este libro es una introducción a la Química Orgánica, para estudiantes de carreras médicas, Microbiología, Biología, Agricultura, Veterinaria. Llena un vacío entre textos escolares y libros de texto de la carrera de Química. -
Fungi with history: Unveiling the mycobiota of historic documents of Costa Rica
(2022-06-12)Through nondestructive techniques, we studied the physicochemical characteristics and mycobiota of five key historic documents from Costa Rica, including the Independence Act of Costa Rica from 1821. We determined that for ... -
Fusarium: more than a node or a foot-shaped basal cell
(2021)Recent publications have argued that there are potentially serious consequences for researchers in recognising distinct genera in the terminal fusarioid clade of the family Nectriaceae. Thus, an alternate hypothesis, namely ... -
Gaschromatographische Analyse des Samenfettes der mittelamerikanischen Fevillea Cordifolia (Cucurbitaceae)
(1992)The fat of the seeds of Fevillea cordifolia was extracted under exclusion of oxygen and light and then characterized by 13C-NMR in regard to the contained unsaturated acid moieties. The total fat was separated by HPLC to ... -
General Chemistry Without Orbitals
(2020)We illustrate the solutions of Schroedinger's equation for the hydrogen atom in coordinates of all four systems, and differentiate the applicability of orbitals in these four systems. We present reasons that future textbooks ... -
Germacranolides and other constituents from ageratzna species
(1988)The aerial parts of Ageratina anisochroma gave several thymol derivatives including five new ones, a hydroxypiperitol glucoside, some substituted benzyl benzoates and several germacranolides related to provincialin. From ... -
Germacranolides from Mikania guaco
(2001-03)Fourteen novel sesquiterpene lactones of the germacranolide type have been isolated from the aerial parts of Mikania guaco: six costunolide, two melampolide and six germacra-4-trans,10(14),11(13)-trien-12,6α-olide derivatives. ... -
Granular Activated Carbon Treatment May Result in Higher Predicted Genotoxicity in the Presence of Bromide
(2016-07-28)Certain unregulated disinfection byproducts (DBPs) are more of a health concern than regulated DBPs. Brominated species are typically more cytotoxic and genotoxic than their chlorinated analogs. The impact of granular ... -
Grids II: Aromatic Acidity and Basicity
(2021)The effect of substituents on the acidity of benzoic acids and basicity of anilines has been organized in grids to demonstrate the inductive and resonance effects. The relation between structure and pKa is emphasized ... -
Grids III: Hydrogen Bridges in Introductory Chemistry
(2021)Based on IUPAC recommendations for the definition of the hydrogen bond, a series of grids is presented to provide instructors of introductory chemistry courses with visual examples of H-bridged systems. The grids ... -
Guía de lectura de la Base de Datos para el Estudio de Inteligencia Tecnológica y Científica del Cannabidiol (CBD)
(2023)El Excel cuenta con 3 hojas, donde la primera corresponde a Artículos Científicos, la segunda a Patentes y la última a CIP detalle, las cuales son las siglas para Código Internacional de Patentes. De esta manera, en cada ... -
Guía de mediación pedagógica para aprendizajes comunitarios: comités de agua transfronte- rizos, Costa Rica - Nicaragua : pedagogía social, estrategias para la optimización del uso del agua para consumo humano en las comunidades de La Trocha e Isla Chica en los Chiles, Alajuela
(2021)El equipo de profesores y profesoras de la Universidad Nacional y la Universidad de Costa Rica que elaboró esta guía conforma el proyecto de extensión y acción social universitaria: “Pedagogía social: estrategias para la ... -
Harnessing titanium dioxide surface toward novel functional materials
(2015)The ever-increasing worldwide energy consumption has led the society to quest for novel and functional materials that can be used in the development of solar fuels to some extent lessen the dependence on fossil fuels. In ... -
Heliangolides from Viguiera sylvatica
(1989)The extract of the aerial parts of Viguiera sylvatica gave, in addition to known heliangolides, four new heliangolides related to 1-desoxyniveusin A and one to 11,13-dihydrofuroheliangolide as well as three guaianolides, ... -
Heterogeneous Water Oxidation: Surface Activity versus Amorphization Activation in Cobalt Phosphate Catalysts
(2015)Is water oxidation catalyzed at the surface or within the bulk volume of solid oxide materials? This question is addressed for cobalt phosphate catalysts deposited on inert electrodes, namely crystallites of pakhomovskyite ... -
High and low affinity sites of ferrihydrite for metal ion adsorption: Data and modeling of the alkaline-earth ions Be, Mg, Ca, Sr, Ba, and Ra
(2020-10-01)The alkaline-earth metal ion series comprises Be, Mg, Ca, Sr, Ba, and Ra. Calcium (Ca) and magnesium (Mg) are the most abundant alkaline-earth metal ions in nature and their interaction with the mineral surfaces of metal ... -
Homopropargyl alcohol 1,1-diphenylbut-3-yn-1-ol
(2018)The asymmetric unit of the title compound, C16H14O, contains one molecule with a central carbon atom having a distorted tetrahedral geometry made of a propargylic fragment, a hydroxy group and two aromatic rings. ...