| 1. |
- Eckardt, Johanna, et al.
(author)
-
Long-term frozen storage of wheat bread and dough : Effect of time, temperature and fibre on sensory quality, microstructure and state of water
- 2013
-
In: Journal of Cereal Science. - : Elsevier BV. - 0733-5210 .- 1095-9963. ; 57:1, s. 125-133
-
Journal article (peer-reviewed)abstract
- The objective of this study was to determine effect of storage time, storage temperature and addition of fibre on sensory quality, state of water, microstructure and texture of bread and dough. Samples with and without fibre, were stored frozen for 2, 3.5 and 6 months at temperatures of -19, -16 and -8 °C as dough and bread. Sensory quality was evaluated by a trained analytical panel. Microstructure was analysed by light microscopy. Texture measurements were performed on bread, and the state of water was measured by differential scanning calorimetry. Bread without fibre stored as dough at -19 °C was the sample most like freshly baked bread. Sensory evaluation also confirmed that quality of the final bread was improved if samples were stored as dough compared to stored as bread. The microstructure had larger gaps between the starch and gluten phases when stored at warmer temperatures, due to retrogradation of starch, dehydration of gluten and water migration. DSC measurements showed that bread stored at -19 °C gained extra amount of freezable water, but lost ice after storage at -8 °C. Texture measurements showed that firmness increased with extended storage time. Bread stored at -8 °C had lowest quality in all measurements.
|
|
| 2. |
- Müller, Christian, et al.
(author)
-
Woven Electrochemical Transistors on Silk Fibers
- 2011
-
In: ADVANCED MATERIALS. - : John Wiley and Sons, Ltd. - 0935-9648 .- 1521-4095. ; 23:7, s. 898-
-
Journal article (peer-reviewed)abstract
- Woven electrochemical transistors on silk fibers from the silkworm Bombyx mori are demonstrated. This is achieved with carefully chosen electrolyte chemistry: electrically conducting silk fibers are produced by dyeing silk fibers with a conjugated polyelectrolyte and gating is accomplished by use of an electrolyte mixture composed of imidazolium-based ionic liquids.
|
|
| 3. |
- Seisenbaeva, Gulaim, et al.
(author)
-
Controlling precursor stability and evaporation through molecular design. Pseudo single source precursor approach to MOCVD SrTiO3 thin films
- 2011
-
In: Applied Surface Science. - : Elsevier BV. - 0169-4332. ; 257, s. 2281-2290
-
Journal article (peer-reviewed)abstract
- Strontium titanate SrTiO3 thin films have attracted interest as a possible gate dielectric material. Preparation of its high quality coatings is hindered by difference in volatility of the homometallic precursors - strontium beta-diketonates and titanium alkoxides. The only earlier known single-source precursor, a sec-alkoxide derivative Sr2Ti2(thd)(4)(OiPr)(8), has limited volatility. Bimetallic primary alkyl chain complexes, Sr4Ti2O(thd)(4)(OR)(10)(ROH)(2), R = Et, Pr-n, are stable and volatile, but possess a wrong composition. Highly volatile precursor Sr2Ti2(thd)(4)((OBu)-Bu-i)(8) has been prepared using an iso-alkoxide, combining proper ligand size with the sterical requirements, and characterized by multivariate evaporation analysis. Its evaporation is associated with complete decomposition into homometallic species, which, however, are evaporated in a single step. This permits to successfully use this novel precursor for SrTiO3 thin film deposition by DLI-MOCVD technique in a sufficiently broad established temperature range. Using optimized experimental conditions, 100 nm thick strontium titanate films with high permittivity have been successfully obtained on (100) Si. (C) 2010 Elsevier B.V. All rights reserved.
|
|
| 4. |
- Seisenbaeva, Gulaim, et al.
(author)
-
On the Reliability of Heteronuclear Precursors-Ligand Effects in the Li-MOCVD Synthesis of SrTiO3 Films
- 2011
-
In: Journal of Nanoscience and Nanotechnology. - : American Scientific Publishers. - 1533-4880 .- 1533-4899. ; 11, s. 8302-8308
-
Journal article (peer-reviewed)abstract
- Strontium titanate SrTiO3 thin films are highly perspective as gate dielectric material. Difference in volatility of the common homometallic precursors-strontium beta-diketonates and titanium alkoxides remains major hinder for preparation of high quality coatings based on this phase. An attractive alternative in its synthesis by MOCVD is provided by application of heterometallic mixed-ligand complexes, Sr2Ti2(beta-diket)(4)(OR)(8)(ROH)(x). Mass-spectrometric study reveals, however, that none of these species can be considered a true single-source precursor. The relative stability of the molecules in solution and the congruence of in-situ release of homometallic species on evaporation are, on the other hand, crucial for the quality of the produced films and are strongly influenced by the nature of alkoxide ligands, OR. The historically first discovered representative of this heterometallic family, a sec-alkoxide derivative Sr2Ti2(thd)(4)((OPr)-Pr-i)(8), is in fact unexpectedly unstable, transforming in solution into Sr2Ti(thd)(4)((OPr)-Pr-i)(4)((PrOH)-Pr-i), which explains difficulties in keeping the correct stoichiometry using isopropoxide precursor. The primary alkoxide complexes, Sr2Ti2(thd)(4)(OR)(8)(ROH)(2), R = Et, Pr-n are also unstable yielding Sr4Ti2(thd)(4)(OR)(8)(ROH)(2) on decomposition. The best solution stability and most uniform evaporation was observed for the iso-derivative, Sr2Ti2(thd)(4)((OBu)-Bu-i)(8), permitting to apply it in long term experiments under industrial process conditions. Present contribution provides detailed experimental comparison between and sec-and iso-alkoxide derivatives and sheds light on the influence of the ligand on molecular stability of a precursor and how it influences the quality of the derived oxide film, especially in relation to its electrophysical properties.
|
|
