Sökning: "Hydroxide ion"

Visar resultat 16 - 20 av 43 avhandlingar innehållade orden Hydroxide ion.

1. 16. Quantum Chemical Modelling of Biomimetic Phosphoesterase Complexes

   Författare :Henrik Daver; Fahmi Himo; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

   Sammanfattning : Phosphoesterases are a class of enzymes that catalyze hydrolysis of phosphoester bonds. They facilitate the modification of nucleic acid sequences, as well as the breakdown of rest products of warfare agents and insecticides. In this thesis, three biomimetic complexes that perform the same tasks are studied using density functional theory. LÄS MER

3. 17. Aspects of optimizing pulp fibre properties for tissue and packaging materials

   Författare :Hafizur Rahman; Armando Cordova; Per Engstrand; Börje Norlin; Göran Bengtsson; Mittuniversitetet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

   Sammanfattning : To improve the competitive advantages of pulp fibre-based materials for tissue and packaging over fossil-based products, it is essential to increase knowledge of the selectivity of the cooking and the chemimechanical processes by optimizing the unit operations of impregnation, cooking and refining. A general goal in pulping processes is to achieve as efficient and even fibre separation as possible. LÄS MER

4. 18. The link between kraft cooking and bleaching : influence on ECF bleachabiblity and bleaching effluent parameters

   Författare :Magnus Björklund; []
   Nyckelord :;

   Sammanfattning : The link between kraft cooking and bleaching was investigated, with the focus on how cooking kappa number, cooking conditions and pre-bleaching stages influence ECF bleachability and environmental parameters in the bleaching effluent. In one part of the study standard cooking conditions were used to produce birch and spruce pulps of different kappa numbers and then we studied how the AOX in the ECF bleaching effluent was affected by oxygen delignification, and hot acid stages. LÄS MER

5. 19. Studies of the influence of ZSM-5 synthesis on activity and stability of Cu-ZSM-5 in leand NOx reduction

   Författare :Malin Berggrund; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; HC-SCR; Cu-ZSM-5; catalysis; propene; lean NOx reduction; hydrothermal stability;

   Sammanfattning : The growing concern about the global warming coupled with the increasing emissions of the greenhouse gas carbon dioxide, combined with the climbing oil price, drives the interest to more fuel efficient lean combustion engines for automotive applications. Such engines require new technical solutions for reduction of NOx in the exhaust gases, which are in excess oxygen, where a conventional three-way catalyst cannot be used to reduce NOx. LÄS MER

7. 20. Calculations of Reaction Mechanisms and Entropic Effects in Enzyme Catalysis

   Författare :Masoud Kazemi; Johan Åqvist; Per E. M. Siegbahn; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Enzyme catalysis; Entropy; Cytidine deamination; Ribosome; Peptidyl-tRNA hydrolysis; Peptide bond formation; Empirical valence bond method; Density functional theory; Biology with specialization in Structural Biology; Biologi med inriktning mot strukturbiologi; Biokemi; Biochemistry; Biology with specialization in Molecular Biotechnology; Biologi med inriktning mot molekylär bioteknik;

   Sammanfattning : Ground state destabilization is a hypothesis to explain enzyme catalysis. The most popular interpretation of it is the entropic effect, which states that enzymes accelerate biochemical reactions by bringing the reactants to a favorable position and orientation and the entropy cost of this is compensated by enthalpy of binding. LÄS MER