Search results for "linear"

Unveiling the Different Reactivity of Bent and Linear Three-Atom-Components Participating in [3 + 2] Cycloaddition Reactions

2021

The reactivity of a series of pairs of bent and linear three-atom-component (B-TACs and L-TACs) participating in [3 + 2] cycloaddition (32CA) reactions towards ethylene and electrophilic dicyanoethylene (DCE) have been studied within the Molecular Electron Density Theory. While the pseudodiradical structure of B-TACs changes to that of pseudoradical or carbenoid L-TACs upon dehydrogenation, zwitterionic B-TACs remain unchanged. Conceptual Density Functional Theory (CDFT) indices characterize five of the nine TACs as strong nucleophiles participating in polar reactions towards electrophilic ethylenes. The activation energies of the 32CA reactions with electrophilic DCE range from 0.5 to 22.0…

Parametri tecnologici allo stato plastico e dopo cottura

2011

Aperiodicity in finitely generated bi-ideals and bounded bi-ideals

2014

Disertācijā pētīts aperiodiskums divu vienpusēji bezgalīgu vārdu klašu – galīgi ģenerētu biideālu un ierobežotu bi-ideālu – kontekstā. Gan galīgi ģenerētus bi-ideālus, gan ierobežotus biideālus ir ērti uzdot, izmantojot bāzes virkni. Ierobežotu bi-ideālu gadījumā tiek nofiksēta galīga vārdu kopa, no kuras tiek uzģenerēta bāzes virkne. Savukārt galīgi ģenerētu bi-ideālu gadījumā bāzes virkne ir periodiska, līdz ar to var uzskatīt, ka ir dota galīga bāze. Efektīvā ģenerēšana un zināmie aperiodiskuma nosacījumi kalpo par motivāciju apskatīt galīgi ģenerētu bi-ideālu potenciālo pielietojumu kriptogrāfijā – aperiodisku gadījuma skaitļu ģenerēšanā. Savukārt, ierobežoti bi-ideāli ir galīgi ģenerēt…

Nonlinear optical properties of diaromatic stilbene, butadiene and thiophene derivatives

2021

Series of highly polar stilbene (1a–e), diphenylbutadiene (2a–c) and phenylethenylthiophene (3a–c) derivatives were prepared via Horner–Wadsworth–Emmons method with a view to produce new and efficient materials for second harmonic generation (SHG) in the solid-state. The single-crystal X-ray structures of compounds 1–3 reveal extensive polymorphism and a peculiar photodimerization of the 2-chloro-3,4-dimethoxy-4′-nitrostilbene derivative 1a to afford two polymorphs of tetra-aryl cyclobutane 4. The stilbene congeners 2-chloro-3,4-dimethoxy-4′-nitrostilbene (1a·non-centro), 5-bromo-2-hydroxy-3-nitro-4′-nitrostilbene (1b) and 4-dimethylamino-4′-nitrostilbene (1e), as well as 4′-fluoro-4′′-nitr…

Parabolic equations with nonlinear singularities

2011

Abstract We show the existence of positive solutions u ∈ L 2 ( 0 , T ; H 0 1 ( Ω ) ) for nonlinear parabolic problems with singular lower order terms of the asymptote-type. More precisely, we shall consider both semilinear problems whose model is { u t − Δ u + u 1 − u = f ( x , t ) in Ω × ( 0 , T ) , u ( x , 0 ) = u 0 ( x ) in Ω , u ( x , t ) = 0 on ∂ Ω × ( 0 , T ) , and quasilinear problems having natural growth with respect to the gradient, whose model is { u t − Δ u + ∣ ∇ u ∣ 2 u γ = f ( x , t ) in Ω × ( 0 , T ) , u ( x , 0 ) = u 0 ( x ) in Ω , u ( x , t ) = 0 on ∂ Ω × ( 0 , T ) , with γ > 0 . Moreover, we prove a comparison principle and, as an application, we study the asymptotic behav…

On the accuracy of three statistical softwares

2005

In this paper we compare the accuracy of three packages that are commonly used for statistical calculations: Excel of Microsoft, version XP Edition 2003, Statistica of Statsoft, version 6, and R, an open-source free software, available on the web, version 1.9.0. To assess the accuracy of each software in different statistical areas, we are going to use benchmarks expressly developed for this aim. The obtained results show a superiority of R in comparison with the other two softwares.

Study of supersymmetric signals with R-parity violation in ATLAS at LHC

2013

219 páginas. Tesis Doctoral del Departamento de Física Atómica, Molecular y Nuclear, de la Universidad de Valencia.

Über gemischte bindungen in der IV. hauptgruppe

1987

Abstract Reaction of Ph3SnLi with Ph2SiCl2 or Ph2GeCl2 at −78°C in THF yields (Ph3Sn)2SiPh2 (1) and (Ph3Sn)2GePh2 (2). The crystal structure of 1 (R = 0.075) exhibits SnSi distances of 257.2(4) and 257.9(5) pm, an SnSiSn angle of 118.5(2)°, and a central C3SnSiC2SnC3 molecular skeleton with symmetry close to C2. The geminal NMR coupling 2J(119Sn ⋯ 119Sn) in 1, and in a tri-, tetra- and pentastannane series shows a linear correlation to their respective non-bonded d(Sn ⋯ Sn) distances (I(t-Bu2Sn)4I: 20 Hz/496 pm; 1: 724 Hz/443 pm).

Authentication of the protected designation of origin horchata de Valencia through the chemometric treatment of mineral content

2010

Spanish horchata de chufa samples were authenticated based on the determination of mineral elements by inductively coupled plasma atomic emission spectrometry (ICP-OES) combined with different chemometric methods. The ability of multivariate analysis, such as principle components analysis (PCA), classification and regression trees (CARTs) and discriminant analysis (DA) were evaluated in order to achieve a correct sample classification. It was possible to clearly differentiate homemade and long-life commercial samples by all three methods and CART and DA provided an excellent tool to establish the growth origin of the tiger nuts. CART analysis employed the concentration of Mg to discriminate…

Global linear feedback control for the generalized Lorenz system

2006

Abstract In this paper we show how the chaotic behavior of the Chen system can be controlled via feedback technique. We design both a nonlinear feedback controller and a linear one which globally regulate the closed-loop system states to a given point. We finally show that our approach works also for the whole family of the generalized Lorenz system.