Search results for "oio"

Un esperimento sulla distribuzione di velocità degli elettroni in una valvola termoionica

2012

In questo lavoro è discusso un approccio sperimentale alla distribuzione di Maxwell- Bolzmann. A partire dallo studio delle caratteristiche I-V dei triodi a vuoto, si perviene, utilizzando un semplice modello, alla distribuzione di velocità degli elettroni emessi dal catodo dei dispositivi utilizzati. L’esperimento qui proposto può aiutare gli studenti a focalizzare l’attenzione sul concetto di distribuzione di velocità in un sistema di particelle, senza distrarli dalle difficoltà concettuali connesse alla complessità del fenomeno dell’emissione termoionica.

Distinct photodynamics of κ-N and κ-C pseudoisomeric iron(ii) complexes

2021

Two closely related FeII complexes with 2,6-bis(1-ethyl-1H-1,2,3-triazol-4yl)pyridine and 2,6-bis(1,2,3-triazol-5-ylidene)pyridine ligands are presented to gain new insights into the photophysics of bis(tridentate) iron(II) complexes. The [Fe(N^N^N)2]2+ pseudoisomer sensitizes singlet oxygen through a MC state with nanosecond lifetime after MLCT excitation, while the bis(tridentate) [Fe(C^N^C)2]2+ pseudoisomer possesses a similar 3MLCT lifetime as the tris(bidentate) [Fe(C^C)2(N^N)]2+ complexes with four mesoionic carbenes. Financial support from the Deutsche Forschungsge-meinschaft [DFG, Priority Program SPP 2102] "Light-controlled reactivity of metal complexes" (BA 4467/7-1, LO 714/11-1, …

Ryhmänohjauksen kehittäminen Voionmaan lukiossa

2005

Development of a coupled diffusion denuder system combined with gas chromatography/mass spectrometry for the separation and quantification of molecul…

2009

This study concerns the development of a coupled diffusion denuder system capable of separating and quantifying gaseous molecular iodine (I(2)) and two other highly reactive iodine species, ICl and HOI, which are collectively named activated iodine compounds (AIC). Both I(2) and AIC are key species in the atmospheric chemistry of iodine. 1,3,5-Trimethoxybenzene (1,3,5-TMB)- and alpha-cyclodextrin/(129)I(-) (alpha-CD/(129)I(-))-coated denuders proved to be suitable for the collection of gaseous AIC and I(2), respectively. The experimental collection efficiencies for AIC (tested as ICl) and I(2) agreed well with the theoretical values for gas flow rates in the range between 300 and 1800 mL mi…

Synthesis and radical polymerization of novel methacrylates with mesoionic 6-oxo-1,6-dihydropyrimidin-3-ium-4-olates as photosensitive components

2001

New polymerizable mesoionic 6-oxo-1,6-dihydropyrimidin-3-ium-4-olates 5a-f have been synthesized using tosylated 2-hydroxymethyl methacrylate and various thioureas and malonic acids. Radical polymerization of the mesoionic derivatives 5a, c, d, e with AIBN as initiator resulted in soluble polymers, which were used for the preparation of photosensitive films.

Iodomethane Oxidation by Dimethyldioxirane:  A New Route to Hypoiodous Acid and Iodohydrines

1999

The oxidation of iodomethane with dimethyldioxirane allows the generation of stable neutral solutions of hypoiodous acid in the absence of any trapping agent for iodide anion. Hypoiodous acid is trapped in situ by addition to representative olefins to give iodohydrines in good yields. The stereochemical study of the products shows the anti-stereospecific nature of the iodohydroxylation reaction.

Modelling molecular iodine emissions in a coastal marine environment: The link to new particle formation

2006

International audience; A model of iodine chemistry in the marine boundary layer (MBL) has been used to investigate the impact of daytime coastal emissions of molecular iodine (I2). The model contains a full treatment of gas-phase iodine chemistry, combined with a description of the nucleation and growth, by condensation and coagulation, of iodine oxide nano-particles. In-situ measurements of coastal emissions of I2 made by the broadband cavity ring-down spectroscopy (BBCRDS) and inductively coupled plasma-mass spectrometry (ICP/MS) techniques are presented and compared to long path differential optical absorption spectroscopy (DOAS) observations of I2 at Mace Head, Ireland. Simultaneous me…

Programas Educativos Universitarios Para Mayores: Evaluación de su Impacto en la Autopercepción del Apoyo Social y la Salud Mental

2015

Algunos estudios indican que los programas universitarios para mayores pueden tener un impacto positivo en la autopercepción del apoyo social y la salud de los participantes. Sin embargo, dichos estudios no evalúan estas variables con instrumentos de medida estandarizados y grupos de control dentro y fuera del programa. En el presente trabajo se utilizó un grupo experimental y dos grupos control que fueron evaluados en dos momentos con instrumentos estandarizados. Los resultados no confirmaron los efectos beneficiosos esperados de los programas. Es necesario seguir profundizando en esta línea de actuación y explorar el efecto de variables socioafectivas en estudios longitudinales. Some stud…

Σύμβολα, σημεῖα, ὁμοιώματα: ripensando l’incipit del De interpretatione

2021

This paper deals with the first lines of Aristotle’s De interpretatione. Starting from Lo Piparo’s (2003) authoritative reading, I try to show that symbolon does not mean either ‘symbol’ or ‘sign’ in the sense commonly ascribed to these words. On etimological grounds (see symballo), I suggest that symbolon means something as ‘mark’, ‘countresign’, i.e., a double-faced unity. In any case, symbolon establishes a symmetric relation between its relata: if A is symbolon of B, B is symbolon of A. On the contrary, semeion (i.e. ‘sign’, for example a tombstone on a grave) establishes an asymmetric relation between its relata: if A is semeion of B, B cannot be semeion of A. Lo Piparo thinks that Ari…

On the Way to Optoionics

2020

Discussions with Michael Grätzel, Ursula Röthlisberger, Robert A. Evarestov and Bettina V. Lotsch are gratefully acknowledged.