Search results for " Rotation"

Über die polymeranaloge bromierung von naturkautschuk und einige lösungseigensch aften des bromkautschuks. Über die molekularen konstanten von naturk…

1961

Naturkautschuk last sich in verdunnter Losung in Cyclohexan bromieren, wobei das Molekulargewicht entsprechend dem Bromgehalt zunimmt (polymeranaloge Umsetzung). Fur Bromkautschuk steigenden Bromgehalts wird Cyclohexan ein zunehmend schlechteres Losungsmittel, was sich in einer Abnahme des 2. osmotischen Virialkoeffizienten und einer Kontraktion des Molekulknauels zeigt. Dieses Ergebnis wird in quantitativer Ubereinstimmung durch Viskositats- und Lichtstreuungsmessungen erhalten. Cyclohexanlosungen von Bromkautschuk mit 43% Brom haben bei Zimmertemperatur einen Θ-Punkt. In diesem Zustand ist der Knauel 1,74mal groser als bei freier Drehbarkeit, in ziemlich guter Ubereinstimmung mit dem an a…

Absolute Configuration Determination of 2,3-Dihydro-1H,5H-pyrazolo[1,2-a]pyrazoles Using Chiroptical Methods at Different Wavelengths

2016

A correlation between the absolute configuration and chiroptical properties of nonracemic 1,6,7-trisubstituted 2,3-dihydro-1H,5H-pyrazolo[1,2-a]pyrazoles was studied. A series of 16 novel representatives were prepared by Cu-catalyzed [3 + 2] cycloadditions of racemic (Z)-2-benzylidene-5-oxopyrazolidin-2-ium-1-ides to tert-butyl (S)-(3-oxopent-4-yn-2-yl)carbamate, and their structures were determined by NMR, VCD, ECD, and X-ray diffraction. A clear correlation between the sign of specific rotation and configuration at position C(1) allows for easy determination of the absolute configuration of 1,6,7-trisubstituted 2,3-dihydro-1H,5H-pyrazolo[1,2-a]pyrazoles by ECD and NMR. While VCD, requirin…

ALIGNEMENT UNI ET TRIDIMENSIONNEL DE MOLÉCULES PAR IMPULSION LASER FEMTOSECONDE

2007

This thesis is devoted to the study of the alignment of linear and asymmetric top molecules generated by an intense laser pulse. In the case of short pulses with respect to molecular rotation, periodic alignment appears in field-free conditions after the extinction of the field. We study theoretically and experimentally the effects of intensity, temperature and polarization of the electric field on produced alignment. If the field is linearly polarized, the interaction leads to the alignment of the most polarizable axis of the molecule. If the field is elliptically polarized, the pulse can generate a simultaneous alignment of the three principal axes of inertia of an asymmetric top molecule…

Crop rotation, nitrogen fertilization and genotype effects on durum wheat productive characteristics

2004

A field trial was performed in 2000/01 and 2001/02 in the experimental farm “Sparacia” (Cammarata – AG – Sicily) in order to evaluate the qualitative and quantitative response of four varieties of durum wheat when grown after a legume crop (field pea) or in rotation with itself and when submitted to different N-fertilization levels: no fertilization (N0, control), 60 kg ha-1 (N 60, rate advised by the EC n. 2078/92 for the Sicilian territory) and 120 kg ha-1 (N 120, fertilization rate commonly used under the “traditional” cropping technique). In the first trial year, the fertilized trial expressed a better yield performance than the control, but in 2001/02, characterized by severe and prolo…

Microbial biomass carbon dynamics in a long-term tillage and crop rotation experiment under semiarid Mediterranean conditions

2015

Microbial biomass carbon (MBC) of soil is an important ecological indicator of nutrient cycling and soil fertility. In addition, it responds to the changes of soil fertility more rapidly than soil organic matter. The aim of the present work was to evaluate the effect of a long-term implementation of a conservative soil management strategy (No Tillage [NT]) compared to the inversion tillage (conventional tillage [CT]) on the soil MBC in a range of crops - continuous durum wheat (WW), wheat after fababean (FW) and faba bean after wheat (WF). MBC of NT plots was higher than CT. In addition, the content of MBC varied with sampling time during the growing season; this variation did not show a co…

Restrictive Factors for Micro-Company Growth in Latvia

2020

Every country is interested in entrepreneurship development as entrepreneurs form the basis for economic development, so academic researchers are looking for supportive and restrictive factors in business development. In Latvia, the majority of companies are micro and small enterprises. The aim of the paper is to investigate the restrictive factors related to the successful development of the company in Latvia, depending on the number of employees. Tasks of the research - evaluate the limiting factors influencing the development of micro-companies; find the most important factors that limit the involvement of employees and experienced managers in companies in the country, regions; compare t…

How Do Young People Cope with Job Flexibility?: Demographic and Psychological Antecendents of the Resistance to Accept a Job with Non-Preferred Flexi…

2002

La flexibilite est souvent vue comme condition necessaire a la survie des marches de travail nationaux et a celle des organisations dans un monde en rapide changement ou s’accroit la competition globale. Elle a adopte diverses formes tels les contrats a duree determinee, l’externalisation, les horaires flexibles, le temps partiel, les heures complementaires, le roulement fonctionnel. De plus, il a ete declare que la flexibilite organisationnelle se doit d’etre accompagnee d’une flexibilite personnelle. Quoi qu’il en soit, face aux nouvelles opportunites de travail, les gens different tant sur le plan de leurs preferences que sur celui de leur comportement. Le but de cette etude est d’identi…

The Jacobi-Maclaurin pattern and some of its physical applications

2005

Preparation of 2,3-seco-5α-cholestane-2,3-diol and 4α-methyl-2,3-seco-5α-cholestane-2,3-diol and its reactions with o-nitrophenyl selenocyanate

1984

The reaction of 2,3-seco-5 alpha-cholestane-2,3-diol and 4 alpha-methyl-2,3-seco-5 alpha-cholestane-2,3-diol with o-nitrophenyl selenocyanate was studied. The diols were synthesized from cholesterol.

Multiplicity results for asymmetric boundary value problems with indefinite weights

2004

We prove existence and multiplicity of solutions, with prescribed nodal properties, to a boundary value problem of the formu″+f(t,u)=0,u(0)=u(T)=0. The nonlinearity is supposed to satisfy asymmetric, asymptotically linear assumptions involving indefinite weights. We first study some auxiliary half-linear, two-weighted problems for which an eigenvalue theory holds. Multiplicity is ensured by assumptions expressed in terms of weighted eigenvalues. The proof is developed in the framework of topological methods and is based on some relations between rotation numbers and weighted eigenvalues.