Search results for "typpi"

N-(2,3,5,6-Tetrafluoropyridyl)sulfoximines : synthesis, X-ray crystallography, and halogen bonding

2020

In the presence of KOH, NH-sulfoximines react with pentafluoropyridine to give N-(tetrafluoropyridyl)sulfoximines (NTFP-sulfoximines) in moderate to excellent yields. Either a solution-based or a superior solvent-free mechanochemical protocol can be followed. X-Ray diffraction analyses of 26 products provided insight into the bond parameters and conformational rigidity of the molecular scaffold. In solid-state structures, sulfoximines with halo substituents on the S-bound arene are intermolecularly linked by C–X⋯O[double bond, length as m-dash]S (X = Cl, Br) halogen bonds. Hirshfeld surface analysis is used to assess the type of non-covalent contacts present in molecules. For mixtures of th…

Kutupesän ominaisuudet sekä mätimunien isotooppikoostumus kuteneiden taimenten (Salmo trutta) koon ja vaellusten arvioinnin työkaluna

2015

Taimen (Salmo trutta L.) on kasvu- ja elinkiertostrategioiltaan monipuolinen kalalaji. Se voi elää koko elinikänsä niin pienissä puroissa kuin suuremmissa joissa, käyden mahdollisella syönnösvaelluksella järvellä tai merellä. Eri alueilla eläessään ja ruokaillessaan taimen käyttää isotooppiselta koostumukseltaan hyvinkin erilaista ravintoa. Ravinnon mukana tulevien typen ja hiilen vakaiden isotooppien suhteet pystytään määrittämään kalan suomuista ja niiden perusteella voidaan melko luotettavasti päätellä, onko kyseinen yksilö käynyt syönnöksellä järvessä tai meressä vai viettänyt valtaosan ajastaan paikallisena yksilönä joessa. Myös taimenen mätimunista voidaan määrittää isotooppisuhteet. …

Sources of nitrous oxide and the fate of mineral nitrogen in subarctic permafrost peat soils

2022

Nitrous oxide (N2O) emissions from permafrost-affected terrestrial ecosystems have received little attention, largely because they have been thought to be negligible. Recent studies, however, have shown that there are habitats in the subarctic tundra emitting N2O at high rates, such as bare peat (BP) surfaces on permafrost peatlands. Nevertheless, the processes behind N2O production in these high-emission habitats are poorly understood. In this study, we established an in situ 15N-labeling experiment with two main objectives: (1) to partition the microbial sources of N2O emitted from BP surfaces on permafrost peatlands and (2) to study the fate of ammonium and nitrate in these soils and in …

Modelling phytoplankton in boreal lakes

2014

Microbial controls of greenhouse gas emissions from boreal lakes

2015

Maankäytön ja maaperäeläinten vaikutus ravinteiden ja torjunta-aineiden valuntaan peltomaasta

2011

Tehomaatalous pyrkii maksimoimaan maan tuottavuutta. Samalla se saattaa kuitenkin vaikuttaa negatiivisesti agroekosysteemien ravinnekiertoon ja maaperän rakenteeseen. Maaperäeläinten toiminnallisen monimuotoisuuden pieneneminen voi osaltaan heikentää maan ravinnekiertoa ja rakennetta. Tässä tutkimuksessa kasvatettiin mikrokosmoksissa vehnää ja verrattiin tehomaatalouskäytössä olleen maan ja laidunmaan kykyä pidättää ravinteita (N) ja torjunta-aineita (metributsiini) sekä tutkittiin, miten änkyrimadot ja lierot vaikuttavat ravinteiden ja torjunta-aineen valuntaan. Laidunmaa pidätti torjunta-ainetta paremmin kuin tehomaatalousmaa, mikä johtui lähinnä laidunmaan suuremmasta orgaanisen aineen p…

The Nature of Transannular Interactions in E4N4 and E82+ (E = S, Se)

2012

The electronic structures of tetrachalcogen tetranitrides, E4N4, and octachalcogen dications, E82+, and the nature of their intramolecular E···E interactions (E = S, Se) was studied with high-level theoretical methods. The results reveal that the singlet ground states of both systems have a surprisingly large correlation contribution which functions to weaken and therefore lengthen the cross-ring E–E bond. The observed correlation effects are primarily static in E4N4, whereas in E82+ the dynamic part largely governs the total correlation contribution. The presented description of bonding is the first that gives an all-inclusive picture of the origin of cross-ring interactions in E4N4 and E8…

Structures and EPR spectra of binary sulfur−nitrogen radicals from DFT calculations

2007

he scattered electron paramagnetic resonance (EPR) spectroscopic data for binary sulfur–nitrogen (S,N) radicals have been compiled and critically assessed.Many of these are inorganic rings or cages.For each species, possible equilibrium structures in the gas phase and the EPR hyperfine coupling (hfc) constants have been calculated with DFT using the B3LYP functional and basis sets of triple-ζ (or better) quality.Good agreement is obtained between calculated and measured values for the well characterized [S3N2]+radical dot, a planar π-radical for which the s-component of the orbitals is likely to be reasonably independent of minor geometrical changes between gas-phase and condensed-phase sta…

Electrochemical and Electronic Structure Investigations of the [S3N3]• Radical and Kinetic Modeling of the [S4N4]n/[S3N3]n (n = 0, −1) Interconversion

2009

Voltammetric studies of S4N4 employing both cyclic (CV) and rotating disk (RDE) methods in CH2Cl2 at a glassy carbon electrode reveal a one-electron reduction at −1.00 V (versus ferrocene/ferrocenium), which produces a second redox couple at −0.33 V, confirmed to be the electrochemically generated [S3N3]− by CV studies on its salts. Diffusion coefficients (CH2Cl2/0.4 M [nBu4N][PF6]) estimated by RDE methods: S4N4, 1.17 × 10−5 cm2 s−1; [S3N3]−, 4.00 × 10−6 cm2 s−1. Digital simulations of the CVs detected slow rates of electron transfer for both couples and allowed for a determination of rate constants for homogeneous chemical reaction steps subsequent to electron transfer. The common paramet…

The use of industrial waste materials for the simultaneous removal of ammonium nitrogen and phosphate from the anaerobic digestion reject water

2020

The European Union’s circular economy strategy aims to increase the recycling and re-use of products and waste materials. According to the strategy, the use of industry waste materials and side flows is required to be more effective. In this research, a chemical precipitation method to simultaneously remove ammonium and phosphate from the reject water of anaerobic digestion plant using calcined paper mill sludge and fly ash as a precipitant, was tested. Paper mill sludge is a waste material formed in the paper-making process, and fly ash is another waste material formed in the power plant. Objective of this research was to test whether these industrial waste streams could be used as low cos…