Browse

You are looking at 1 - 10 of 88,552 items

Restricted access

Piotr Musznicki

Open access

Raumforschung und Raumordnung

Spatial Research and Planning

Open access

Dongyun Guo, Yang Ju, Chengju Fu, Zhixiong Huang and Lianmeng Zhang

Abstract

Zinc acetate was used as a starting material to prepare Zn-solutions from solvents and ligands with different boiling temperature. The ZnO thin films were prepared on Si(1 0 0) substrates by spin-coating method. The effect of baking temperature and boiling temperature of the solvents and ligands on their morphologies and orientation was investigated. The solvents and ligands with high boiling temperature were favorable for relaxation of mechanical stress to form the smooth ZnO thin films. As the solvents and ligands with low boiling temperature were used to prepare Zn-solutions, the prepared ZnO thin films showed (0 0 2) preferred orientation. As n-propanol, 2-methoxyethanol, 2-(methylamino)ethanol and monoethanolamine were used to prepare Zn-solutions, highly (0 0 2)-oriented ZnO thin films were formed by adjusting the baking temperature.

Open access

Diana C. G. A. Pinto, João M. P. Pereira and Artur M. S. Silva

Open access

Daniel W. Cranston, Sogol Jahanbekam and Douglas B. West

Abstract

The 1, 2, 3-Conjecture states that the edges of a graph without isolated edges can be labeled from {1, 2, 3} so that the sums of labels at adjacent vertices are distinct. The 1, 2-Conjecture states that if vertices also receive labels and the vertex label is added to the sum of its incident edge labels, then adjacent vertices can be distinguished using only {1, 2}. We show that various configurations cannot occur in minimal counterexamples to these conjectures. Discharging then confirms the conjectures for graphs with maximum average degree less than 8/3. The conjectures are already confirmed for larger families, but the structure theorems and reducibility results are of independent interest.

Open access

Francisca Lopes, Maria M. M. Santos and Rui Moreira

Open access

Bhawna Srivastava, Diwakar Mishra, Sunil Srivastav, Nobuo Suzuki and Ajai Srivastav

1,25(OH)2D3 Induced Alterations in Plasma Calcium, Inorganic Phosphate, Ultimobranhial Gland and Parathyroid Gland of the Garden Lizard, Calotes Versicolor

Garden lizards Calotes versicolor were procured and given daily intraperitoneal injections of 30 pmol of 1,25(OH)2 D3/50 g body wt for 30 days. Lizards were sacrificed on the 1st, 3rd, 5th, 10th, 15th and 30th day of the experiment. The plasma calcium levels of C. versicolor remain unaffected after day 1 following 1,25(OH)2D3 treatment. After day 3 the levels increase significantly which progresses up to day 10. Thereafter, the plasma calcium level tends to decrease on day 15 and the levels become normal at day 30. In 1,25(OH)2D3 injected lizards the plasma inorganic phosphate levels remain unaltered up to day 3. After day 5, the value increases significantly. This increase progresses up to day 15. On day 30, the levels become almost normal. The ultimobranchial gland exhibits hyperactivity following 5 day 1,25(OH)2D3 treatment which is expressed by an increase in the nuclear volume and weak staining response of the cytoplasm of ultimobranchial cells. After day 10, the nuclear volume is further increased and some of the cells are exhausted. Following 15 days 1,25(OH)2D3 treatment the nuclear volume records an increase and many degenerating cells are discerned. After day 30, the nuclear volume is almost normal, most cells seem to be recovered and only a few degenerating cells are noticed. After day 10 and day 15 following 1,25(OH)2D3 treatment, the parathyroid glands of C. versicolor show reduced chromaticity of nuclei and a progressive decrease in the nuclear volume of parathyroidal cells. On day 30, the nuclear volume tends to become normal and a few degenerating cells are observed.

Open access

L. Anteina, A. Gaidule and A. Zicmanis

Abstract

We report the preparation, characterization and exploitation of 1,3-dialkylimidazolium dimethyl phosphates. Condensation reactions of benzaldehyde with ethyl cyanoacetate and with malonic acid were performed in these ionic liquids either in absence or in presence of other catalysts. The effect of ionic liquid structure on the condensation reaction rates and yields was discussed

Open access

Andriy Tupys and Oleksandr Tymoshuk

Abstract

A simple method for the determination of Pd2+-ions using the azo dye 1-(5-benzylthiazol-2-yl)azonaphthalen-2-ol (or BnTAN) and toluene or chloroform as extraction media is proposed. The palladium(II) ion interacts with 1-(5-benzylthiazol-2-yl)azonaphthalen-2-ol creating a chelate complex. This compound was extracted into toluene and chloroform from the alkaline and acid aqueous solutions respectively. Obtained extracts showed absorbance maxima at 600 and 684 nm. Obedience to Beer’s law was established in the range of 0.261 to 0.850 μg mL−1 of Pd(II) and the molar absorptivity of the complex of 6.70 · 103 L mol−1 cm−1 was determined. Optimum reaction conditions for complexation, the effect of variables like time of heating and pH were studied. Detailed studies to check the Pd2+ : BnTAN – stoichiometric ratio were carried out. The method was successfully applied for the analysis of Pd(II) in details of electronic devices.