Fluorescence properties of full-color-emitting BCNO phosphors synthesized under different oxygen pressure

2014 ◽  
Vol 07 (05) ◽  
pp. 1450053 ◽  
Author(s):  
Feng Zhang ◽  
Weifeng Zhang ◽  
Guoqiang Li ◽  
Yachun Wang ◽  
Hua Yuan

The colorful BCNO phosphors comprised of boron, carbon, nitrogen, and oxygen atoms have been novelty synthesized by varying the environmental oxygen pressure without changing the compositions of the raw materials such as boric, urea, and poly-ethylene glycol. X-ray diffraction (XRD), fourier-transformed infrared (FTIR), and photoluminescence (PL) spectra were employed to characterize the effect of environmental oxygen pressure on the structure and PL properties of the synthesized phosphors. The results of their PL properties indicates that the emission color of these BCNO phosphors has been easily tailored for a large-range from violet to near-red regions through variations of the environmental oxygen pressure as prepared under the excitation of 365 nm. This provides a new approach to tailor the emitting colors.

2013 ◽  
Vol 718-720 ◽  
pp. 172-175
Author(s):  
Song Hua Kong ◽  
Mi Zhou ◽  
Xiao Feng Ye ◽  
Xin Qian

Poly(ethylene glycol) methyl ether-grafted-graphene oxide (GO) was synthesized by a coupling reaction and formed inclusion complexes (ICs) after selective threading of the mPEG segments of the GO-mPEG through the cavities of α-cyclodextrins (α-CDs) units. The polypseudorotaxane structures of the as-obtained hydrogels were confirmed by X-ray diffraction, TGA, DSC, and SEM. The complexation of the mPEG segments with α-CDs and the hydrogen-bond interaction between CDs resulted in the formation of supramolecular hybrid hydrogels with a strong network. The resultant hybrid hydrogels were found to be thermo-responsive, and could be applied as a promising drug delivery system.


2020 ◽  
Vol 16 ◽  
pp. 2929-2936
Author(s):  
Emese Gal ◽  
Luiza Gaina ◽  
Hermina Petkes ◽  
Alexandra Pop ◽  
Castelia Cristea ◽  
...  

This work describes an efficient, simple, and ecofriendly sonochemical procedure for the preparation of new α-(arylamino)acetonitrile derivatives C-substituted with phenothiazine or ferrocene units. The synthetic protocol is based on the Strecker reaction of a (hetero)aryl aldimine substrate with trimethylsilyl cyanide (TMSCN) in poly(ethylene glycol) (PEG) solution. The advantages of the sonochemical versus the conventional α-(arylamino)acetonitrile synthesis are the significantly shorter reaction time (30 min instead of 72 hours), the higher purity and the easier separation of the product that precipitated from the reaction mixture in crystalline form as depicted by scanning electron microscopy (SEM) analysis. The single crystal X-ray diffraction analysis disclosed the arrangement of the α-(arylamino)acetonitrile molecules in the aggregated crystalline state as a racemic mixture. The mutagenic/antimutagenic potential for three representative derivatives containing phenothiazinyl, ferrocenyl, and phenyl units, respectively, was evaluated by the Ames Salmonella/microsome test using S. typhimurium TA98 and TA100 strains with and without metabolic activation. The preliminary screening results pointed out that the C-(hetero)aryl-α-(arylamino)acetonitrile derivatives can be considered genotoxically safe and possibly antimutagenic.


2007 ◽  
Vol 15 (5) ◽  
pp. 389-393
Author(s):  
Hong Hao ◽  
Guozheng Liang ◽  
Junmin Zhao

The crystallization behaviour of poly(L-lactide) (PLLA) samples prepared in large-molecule solvents, such as poly(ethylene glycol) (PEG), was studied by differential scanning calorimetry (DSC) and X-ray diffraction. The results indicate that those samples recovered from large-molecule solvents exhibit higher crystallinity, non-isothermal crystallization temperature and faster crystallization rate than the ones crystallized in a small-molecule solvent. The crystallinity of samples from PLLA/PEG gel is about 73% measured by the DSC. The molar size of the solvent has a large influence on the formation of helical conformations and, thereby on the crystallization rate of PLLA in solution.


2013 ◽  
Vol 46 (6) ◽  
pp. 2369-2375 ◽  
Author(s):  
Hanako Asai ◽  
Kenta Fujii ◽  
Kengo Nishi ◽  
Takamasa Sakai ◽  
Koji Ohara ◽  
...  

Author(s):  
T. Hemalatha ◽  
S. Akilandeswari

Pure CuO nanoparticles and chemically-precipitated Poly Ethylene Glycol (PEG) used as a capping agent CuO nanocrystal continuum (0.1, 0.2, 0.3, 0.4, 0.5 gm) was anatomized for structural and morphological research using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and Field - Emission Scanning Electron Microscopy (FE-SEM). Their X-ray Diffraction (XRD) analysis manifested monoclinic crystallinity in pure and PEG-capped CuO nanorods, with an average crystallite size of 21.63nm and 13-16nm respectively. The morphological analysis revealed their structural conformation. The FT-IR spectrum affirmed the presence of Cu-O bonds. The optical property of the aforesaid nanorods was studied by UV-Visible reflectance (UV-Vis DRS). The UV analysis showed that all the capped products show signs of good optical quality in the UV region and also the absorption edge was blue shifted with a band gap of 1.85 eV for 0.4gm PEG capped as results of quantum confinement effect. The antibacterial properties of the as-prepared nanostructures investigated for various human pathogens using disc diffusion method. The result showed the significant antibacterial activity bothgram positiveandgram negativebacteria.


2020 ◽  
Vol 40 (4) ◽  
pp. 350-359
Author(s):  
Nesma Baa Belmessaoud ◽  
Naima Bouslah ◽  
Nabila Haddadine

AbstractIn this study we report on the preparation and characterization of biocomposites based on a sodium montmorillonite-ibuprofen (MtIb) hybrid and neat poly(ethylene glycol), neat sodium carboxymethylcellulose or poly(ethylene glycol)-carboxymethylcellulose blend 50/50 biocomposites as drug carriers. Ib, a poorly soluble drug, was first intercalated into sodium Mt and then the resulting hybrid was compounded with the different polymeric matrices. Ib incorporation efficiency in Mt was determined by UV-visible spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction and thermal analysis. Both X-ray diffraction and differential scanning calorimetric studies revealed that the intercalation of Ib between the clay layers induced amorphization of the drug. Differential scanning calorimetry and Fourier transform infrared spectroscopy revealed the development of strong interactions between Ib and the polymer matrix. A study of the release of Ib from the synthesized biocomposites in simulated intestinal fluid (pH 7.4) was investigated. To better understand the release mechanism of drug molecules from the different carriers, several kinetic models have been applied.


2021 ◽  
Vol 5 (2) ◽  
pp. 16
Author(s):  
Isabel Padilla ◽  
Maximina Romero ◽  
José I. Robla ◽  
Aurora López-Delgado

In this work, concentrated solar energy (CSE) was applied to an energy-intensive process such as the vitrification of waste with the aim of manufacturing glasses. Different types of waste were used as raw materials: a hazardous waste from the aluminum industry as aluminum source; two residues from the food industry (eggshell and mussel shell) and dolomite ore as calcium source; quartz sand was also employed as glass network former. The use of CSE allowed obtaining glasses in the SiO2-Al2O3-CaO system at exposure time as short as 15 min. The raw materials, their mixtures, and the resulting glasses were characterized by means of X-ray fluorescence, X-ray diffraction, and differential thermal analysis. The feasibility of combining a renewable energy, as solar energy and different waste for the manufacture of glasses, would highly contribute to circular economy and environmental sustainability.


Minerals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 232
Author(s):  
Pedro J. Sánchez-Soto ◽  
Eduardo Garzón ◽  
Luis Pérez-Villarejo ◽  
George N. Angelopoulos ◽  
Dolores Eliche-Quesada

In this work, an examination of mining wastes of an albite deposit in south Spain was carried out using X-ray Fluorescence (XRF), X-ray diffraction (XRD), particle size analysis, thermo-dilatometry and Differential Thermal Analysis (DTA) and Thermogravimetric (TG) analysis, followed by the determination of the main ceramic properties. The albite content in two selected samples was high (65–40 wt. %), accompanied by quartz (25–40 wt. %) and other minor minerals identified by XRD, mainly kaolinite, in agreement with the high content of silica and alumina determined by XRF. The content of Na2O was in the range 5.44–3.09 wt. %, being associated with albite. The iron content was very low (<0.75 wt. %). The kaolinite content in the waste was estimated from ~8 to 32 wt. %. The particle size analysis indicated values of 11–31 wt. % of particles <63 µm. The ceramic properties of fired samples (1000–1350 °C) showed progressive shrinkage by the thermal effect, with water absorption and open porosity almost at zero at 1200–1250 °C. At 1200 °C, the bulk density reached a maximum value of 2.38 g/cm3. An abrupt change in the phase evolution by XRD was found from 1150 to 1200 °C, with the disappearance of albite by melting in accordance with the predictions of the phase diagram SiO2-Al2O3-Na2O and the system albite-quartz. These fired materials contained as main crystalline phases quartz and mullite. Quartz was present in the raw samples and mullite was formed by decomposition of kaolinite. The observation of mullite forming needle-shape crystals was revealed by Scanning Electron Microscopy (SEM). The formation of fully densified and vitrified mullite materials by firing treatments was demonstrated.


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