Search results for "ion source"
showing 10 items of 337 documents
Revista electrónica de investigación y evaluación educativa
2014
Resumen basado en el de la publicación Título, resumen y palabras clave en inglés y español Se presenta una herramienta de consulta para investigadores y profesionales de la investigación social. Está compuesta de una selección de fuentes de información útiles clasificadas en cuatro grupos: catálogos, bases de datos, buscadores y páginas Web en Internet, e instrumentos para la comunicación con otros profesionales. Incluye una breve descripción de cada fuente de información y dirección electrónica necesaria para su localización. Valencia ESP
Letters in Arabic sent from the Nasrid Court. A diplomatic analysis
2018
El trabajo aplica las técnicas de la ciencia Diplomática a la correspondencia enviada desde la corte nazarí de Granada a monarcas y señores de los reinos de Aragón y Castilla. Por razones de coherencia y espacio, se centra únicamente en las misivas redactadas en árabe. El objetivo es establecer sus caracteres extrínsecos (tamaño y color del papel, tipo de letra, características del sello, presencia o no deʽalāma) e intrínsecos (manera de dirigirse al destinatario, manera de presentarse, saludos, tipo de datación tópica y crónica), comprobar si con el paso del tiempo hubo evolución en las fórmulas y si se refleja en éstas la categoría social de remitente y destinatario. Las fuentes empleadas…
Profiling of lipid species by normal-phase liquid chromatography, nanoelectrospray ionization, and ion trap–orbitrap mass spectrometry
2013
Detailed analysis of lipid species can be challenging due to their structural diversity and wide concentration range in cells, tissues, and biofluids. To address these analytical challenges, we devised a reproducible, sensitive, and integrated lipidomics workflow based on normal-phase liquid chromatography-Fourier transform mass spectrometry (LC-FTMS) and LC-ITMS(2) (ion trap tandem mass spectrometry) for profiling and structural analysis of lipid species. The workflow uses a normal-phase LC system for efficient separation of apolar and polar lipid species combined with sensitive and specific analysis powered by a chip-based nanoelectrospray ion source and a hybrid ion trap-orbitrap mass sp…
An electrospray ionization Fourier transform ion cyclotron resonance mass spectrometric study of the gas-phase stabilities and fragmentation ofN-alky…
2006
Five N-alkylated ammonium resorcarene derivatives, differing either in the nitrogen atom or in the lower rim alkyl chain, were studied using electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry. The main purpose was to clarify the fragmentation and the relative stabilities of the protonated molecules by collision-induced dissociation (CID) experiments. The results indicate that fragmentation of the upper rim alkyl amino substituents at the 2-position occurs readily. Variation in the gas-phase stabilities of these molecules was also observed. In addition, the proposed fragmentation pathways are depicted.
The cryogenic gas stopping cell of SHIPTRAP
2014
The overall efficiency of the Penning-trap mass spectrometer SHIPTRAP at GSI Darmstadt, employed for high-precision mass measurements of exotic nuclei in the mass region above fermium, is presently mostly limited by the stopping and extraction of fusion-evaporation products in the SHIPTRAP gas cell. To overcome this limitation a second-generation gas cell with increased stopping volume was designed. In addition, its operation at cryogenic temperatures leads to a higher gas density at a given pressure and an improved cleanliness of the helium buffer gas. Here, the results of experiments with a 219Rn recoil ion source are presented. An extraction efficiency of 74(3)% was obtained, a significa…
Cluster calibration in mass spectrometry: laser desorption/ionization studies of atomic clusters and an application in precision mass spectrometry.
2003
For accurate mass measurements and identification of atomic and molecular species precise mass calibration is mandatory. Recent studies with laser desorption/ionization and time-of-flight analysis of cluster ion production by use of fullerene and gold targets demonstrate the generation of atomic clusters for calibration purposes. Atomic ion results from the Penning trap mass spectrometer ISOLTRAP, in which a carbon cluster ion source has recently been installed, are presented as an application in the field of precision mass spectrometry.
El componente pragmático en los diccionarios: Implicaciones para la Lexicografía
2015
Dictionaries are a list of words, simple or complex, that are treated as entries (lexical items). It is usual to assert several components: the lemma or headword, named after its most neutral form, followed by an indication of the main inflections of its category: genre and number if they are names, syntactic class if they are verbs. Sometimes, indications of it are made in other aspects: etymology, pronunciation, marks of placement, area of use, register, frequency of use, etc.Among all the group, it is pointed out an area that grows daily, painstakingly, in lexicographic works: the pragmatic component. Most of the words are referential (names, verbs, adverbs), but others correspond to lan…
Measuring spectrally-resolved information transfer for sender- and receiver-specific frequencies
2020
AbstractInformation transfer, measured by transfer entropy, is a key component of distributed computation. It is therefore important to understand the pattern of information transfer in order to unravel the distributed computational algorithms of a system. Since in many natural systems distributed computation is thought to rely on rhythmic processes a frequency resolved measure of information transfer is highly desirable. Here, we present a novel algorithm, and its efficient implementation, to identify separately frequencies sending and receiving information in a network. Our approach relies on the invertible maximum overlap discrete wavelet transform (MODWT) for the creation of surrogate d…
Accuracy and Completeness of Drug Information in Wikipedia: A Comparison with Standard Textbooks of Pharmacology
2014
The online resource Wikipedia is increasingly used by students for knowledge acquisition and learning. However, the lack of a formal editorial review and the heterogeneous expertise of contributors often results in skepticism by educators whether Wikipedia should be recommended to students as an information source. In this study we systematically analyzed the accuracy and completeness of drug information in the German and English language versions of Wikipedia in comparison to standard textbooks of pharmacology. In addition, references, revision history and readability were evaluated. Analysis of readability was performed using the Amstad readability index and the Erste Wiener Sachtextforme…
Which new semantic for new shapes?
2006
There are two innovations which have drastically changed the building process: the operational continuity of the design and construction phases, and the software allowing not only the representation but also the autonomous creation of complex shapes never before thought of just because they could not be represented. This last innovation gave rise to a new design paradigm whose tools, according to their supporters, are the most advanced fields of mathematics and information science. Some ways of using these new possibilities gave rise to a radical, problematic, change in the relationship net between the designer’s intentions, the shapes through which they express them (invented or self-gener…