Photoluminescence properties of the red phosphor YInGe2O7:Eu3+

Eu3+-doped YInGe2O7 phosphors were prepared via a solid-state reaction with metal oxides and their excitation and emission spectra were measured at room temperature. The results showed that pure-phase YInGe2O7 could be obtained after firing at 1250 °C. The maximum photoluminescence intensity of YInGe2O7:Eu3+ phosphor was achieved when doped with 40 mol% Eu3+ ions. Compared with Y2O2S:0.05Eu3+, the Y0.60InGe2O7:Eu3+0.40 phosphor obtained showed intense red-emission lines at 616 nm, corresponding to forced electric dipole 5D0 → 7F2 transitions of Eu3+ under 394 nm light excitation. The International Commission on Illumination chromaticity coordinates of the phosphors (x = 0.644, y = 0.356) of Y0.60InGe2O7:Eu3+0.40 were close to National Television Standard Committee standard values. As such, the synthesized phosphors may find applications in near ultraviolet InGaN chip-based white light-emitting diodes. KEY WORDS: Optical materials, X-Ray diffraction, Luminescence, Solid state reaction Bull. Chem. Soc. Ethiop. 2013, 27(2), 315-319.DOI: http://dx.doi.org/10.4314/bcse.v27i2.1

Experiment study on the effect of iron ore sinter behavior with adding biomass

This paper focused on the effect of sinter behavior with biomass.The changes of the relevant performance indexes of this sinter behavior, emission laws of harmful gases in flue gas emissions and the mechanism of emission reduction was studied in this paper.The results showed that, when the biomass amount is 0,28 %, the sinter index can meet production requirement, the porosity of sinter increased by 18,5 %, the sinter reduction degree increased by 2,66 %, the SO2 emissions of harmful gases in the flue gas reduced by about 14 %, the amount of NOx about 19 % lower

Enhanced ductility of nanomaterials through cooperative dislocation emission from cracks and grain boundaries

An analytical model is established to explore the cooperative mechanism between the dislocation emission from cracks and grain boundaries driven by grain boundary sliding in deformed nanocrystalline materials. In our model, high local stress concentration nearby the crack actives grain boundary sliding which creates a wedge disclination dipole at the grain boundaries’ triple junctions. The grain size-dependent criterions for the dislocation emission from the crack tip and the grain boundary are respectively derived. Influences of grain boundary sliding and grain size on the cooperative mechanism are discussed. The results show that the dislocation emission from the grain boundary is activated ahead of that from the crack tip for small grain sizes. This can explain that grain boundary sliding can toughen the nanocrystalline materials even though it suppresses dislocation emission from cracks when their grain sizes are relative small, which is because the dislocation emission from grain boundaries is activated. With the increasing grain size, the main dislocation source may transform from grain boundaries to crack tips due to grain boundary sliding. Therefore, the ductility of nanomaterials with different grain sizes can be enhanced through the cooperative dislocation emission from cracks and grain boundaries

The Microvasculature of Human Infant Oral Mucosa Using Vascular Corrosion Casts and India Ink Injection II. Palate and Lip

The microvasculature of human hard and soft palate and lip originating from four infant males and six females, aged 6 months to 2 years was studied by scanning electron microscopy of vascular corrosion casts and light microscopy of India ink injected specimens. The capillary loops of the hard palate mucosa and vermilion border of the lips were found to be tall, numerous and consisted of primary, secondary and tertiary loops. Those of the soft palatal and labial mucosa were short, few in number and demonstrated a simple hair-pin shape originating directly from the subpapillary vascular network. It was concluded that the configuration of capillary loops is not only determined by the shape of the connective tissue papillae in the lamina propria but also influenced by the functional demands characteristic of the different areas of the oral mucosa

Antiproliferative and apoptotic effects of angelicin in highly invasive prostate cancer cells

Purpose: To demonstrate the anti-proliferative activity of angelicin against human prostate cancer (PC- 3) cells and to evaluate its mechanismMethods: MTT (3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide) assay was used to assess the anticancer activity (growth inhibition) of angelicin in PC-3 cells. Fluorescence microscopy using Hoechst  33258 staining and inverted phase microscopy was employed to evaluate the effect of angelicin on nuclear morphology. Flow cytometry, using propidium iodide, was employed to study cell cycle-related effects of angelicin. Apoptosis induction by angelicin was examined by annexin V/PI assay.Results: Angelicin induced potent growth inhibitory effects in human prostate cancer (PC-3) cells in a  dose-dependent manner. Angelicin-treated cells exhibited chromatin condensation which implied an early  apoptotic event. Inverted phase microscopy revealed that reduction of cell population occurred with increase in the angelicin dose. Flow cytometry results showed that angelicin induced cell cycle arrest in the sub-G1 phase. Angelicin induced both early and late apoptosis in PC-3 cells following a dose-dependent pattern.Conclusion: Angelicin inhibits the growth of PC-3 human prostate cancer cells in vitro by inducing early and late apoptosis, cell cycle arrest and chromatin condensation

Effect of microwave irradiation on reactivity of metallurgical coke in CO2 atmosphere

Influence of microwave irradiation on gasification behavior and crystallite parameters of coke samples was studied in this research. The results indicated that microwave irradiation have significant influence on the carbon structure and the reactivity of coke in CO2 atmosphere. The thermogravimetric results showed that the temperature of coke at different conversion rates of 10 %, 20 % and 30 % were reduced by 20 °C, 30 °C and 50 °C respectively. Simultaneously, microwave irradiation may lead to variation in lateral size and stacking height of crystallite and subsequently reduce the gasification reaction rate of coke in CO2 atmosphere