Temperature measurements of the bluff body surface of a Swirl Burner using phosphor thermometry

Flames are often stabilised on bluff-bodies, yet their surface temperatures are rarely measured. This paper presents temperature measurements for the bluff body surface of the Cambridge/Sandia Stratified Swirl Burner. The flame is stabilized by a bluff body, designed to provide a series of turbulent premixed and stratified methane/air flames with a variable degree of swirl and stratification. Recently, modellers have raised concerns about the role of surface temperature on the resulting gas temperatures and the overall heat loss of the burner. Laser-induced phosphorescence is used to measure surface temperatures, with Mg4GeO6F:Mn as the excitation phosphor, creating a spatially resolved temperature map. Results show that the temperature of the bluff body is in the range 550-900 K for different operating conditions. The temperature distribution is strongly correlated with the degree of swirl and local equivalence ratio, reflecting the temperature distribution obtained in the gas phase. The overall heat loss represents only a small fraction (<0.5%) of the total heat load, yet the local surface temperature may affect the local heat transfer and gas temperatures. © 2014 The Combustion Institute.

Phosphor-conversion white light using InGaN ultraviolet laser diode

We fabricated a phosphor-conversion white light using an InGaN laser diode that emits 405 nm near-ultraviolet (n-UV) light and phosphors that emit in the blue and yellow regions when excited by the n-UV and blue light, respectively.The relationship of the luminous flux and the luminous efficacy of the white light with injection current was discussed. The luminous flux increased linearly with increasing current above the threshold of the laser diode, and at 80 mA injection current, the luminous flux and luminous efficacy were estimated to be 5.7 lm and 13 lm/w, respectively. The shift of the Commission International de I'Eclairage coordinates, color temperature, and color rendering index with current are very slight and negligible, which indicates that the blue and the yellow phosphors have an excellent stability and a highly stable white light can be obtained by this way. (c) 2008 American Institute of Physics.

An Efficient Nanocrystalline La2O3:Tm3+ Blue Phosphor for Field-Emission Displays with High Color Purity

Nanocrystalline Tm3+-doped La2O3 phosphors were prepared through a Pechini-type sol-gel process. X-ray diffraction, field-emission scanning electron microscopy, photoluminescence, and cathodoluminescence spectra were utilized to characterize the synthesized phosphors. Under the excitation of UV light (234 nm) and low-voltage electron beams (1-3 kV), the Tm3+-doped La2O3 phosphors show the characteristic emissions of Tm3+(D-1(2), (1)G(4)-F-3(4), H-3(6) transitions).

A multifunctional iridium carbazolyl orange phosphor for high performance two-element WOLED exploiting exciton-managed fluorescence/phosphorescence

By attaching a bulky, inductively electron-with drawing trifluoromethyl (CF3) group on the pyridyl ring of the rigid 2-[3(N-phenylcarbazolyl)]pyridine cyclometalated ligand, we successfully synthesized a new heteroleptic orange-emitting phosphorescent iridium(III) complex [Ir(L-1)(2)(acac)] 1 (HL1=5-trifluoromethyl-2-[3-(N-phenylcarbazolyl)]pyridine, Hacac = acetylacetone) in good yield.

Investigation on charge transfer bands of Ce4+ in Sr2CeO4 blue phosphor

Bulk and nano-materials Sr2CeO4 were prepared by solid-state reaction and sol-gel technique, respectively. Photoluminescence shows that luminescence has the characteristic of a ligand-to-metal charge transfer (CT) emission. Compared with bulk Sr2CeO4, the nano-material exhibits stronger emission intensity, longer decay time, and higher CT excitation energy. Three CT excitation peaks were observed in both bulk and nano samples.

Thermoluminescence characteristics of rare-earth-doped LiCaBO3 phosphor

LiCaBO3 was synthesized by high-temperature solid-state reaction. The influence of different rare earth dopants, i.e. Dy3+, Tb3+. TM3+ and Ce3+, on thermoluminescence (TL) of LiCaBO3 phosphor was discussed. We studied the TL properties and some dosimetric characteristics of Ce3+-activated LiCaBO3 phosphor in detail. The effect of the concentration of Ce3+ on TL was investigated, the result of which showed that the optimum Ce3+ concentration was 1 mol%. The TL kinetic parameters of LiCaBO3:0.01 Ce3+ were studied by computer glow curve deconvolution (CGCD) method.

Avidin conjugation to up-conversion phosphor NaYF4:Yb3+, Er3+ by the oxidation of the oligosaccharide chains

NaYF4:Yb3+, Er3+ nanoparticles were successfully prepared by a polyol process using diethyleneglycol (DEG) as solvent. After being functionalized with SiO2-NH2 layer, these NaYF4:Yb3+, Er3+ nanoparticles can conjugate with activated avidin molecules (activated by the oxidation of the oligosaccharide chain). The as-formed NaYF4:Yb3+, Er3+ nanoparticles, NaYF4:Yb3+, Er3+ nanoparticles functionalized with amino groups, avidin conjugated amino-functionalized NaYF4:Yb3+, Er3+ nanoparticles were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), atomic force microscopy (AFM), Fourier transform infrared (FT-IR), UV/Vis absorption spectra, and up-conversion luminescence spectra, respectively.

Structural and Bluish-White Luminescent Properties of Li+-Doped BPO4 as a Potential Environmentally Friendly Phosphor Material

Many efforts have been devoted to exploring novel luminescent materials that not contain expensive or toxic elements, or do not need a mercury vapor plasma source. In this paper, BPO4 and Li+-doped BPO4 powder samples were prepared by the Pechini-type sol-gel (PSG) process. The structure and optical properties of the resulting samples were characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, field emission scanning electron microscopy (FESEM), photoluminescence (PL) excitation and emission spectra, kinetic decay, and X-ray photoelectron spectra (XPS), respectively. It was found that PSG -derived Li+-doped BPO4 annealed at 960 degrees C exhibited bright bluish-white emission centered at 416 nm. The luminescence decay curves analysis indicates that each sample has two kinds of lifetimes (5.9 ns and 0.529 ms) and two types of kinetic decay behaviors which can be fitted into a single-exponential function and a double-exponential function, respectively.

Avidin conjugation to up-conversion phosphor NaYF4:Yb3+, Er3+ by the oxidation of the oligosaccharide chains

NaYF4:Yb3+, Er3+ nanoparticles were successfully prepared by a polyol process using diethyleneglycol (DEG) as solvent. After being functionalized with SiO2-NH2 layer, these NaYF4:Yb3+, Er3+ nanoparticles can conjugate with activated avidin molecules (activated by the oxidation of the oligosaccharide chain). The as-formed NaYF4:Yb3+, Er3+ nanoparticles, NaYF4:Yb3+, Er3+ nanoparticles functionalized with amino groups, avidin conjugated amino-functionalized NaYF4:Yb3+, Er3+ nanoparticles were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), atomic force microscopy (AFM), Fourier transform infrared (FT-IR), UV/Vis absorption spectra, and up-conversion luminescence spectra, respectively. The biofunctionalization of the NaYF4:Yb3+, Er3+ nanoparticles has less effect on their luminescence properties, i.e., they still show the up-conversion emission (from Er3+, with S-4(3/2) -> I-4(15/2) at similar to 540 nm and F-4(9/2) -> I-4(15/2) at similar to 653 nm), indicative of the great potential for these NaYF4:Yb3+, Er3+ nanoparticles to be used as fluorescence probes for biological system.

Sol-gel derived Y2O3 as an efficient bluish-white phosphor without metal activator ions

In this paper, Y2O3 powder phosphors without metal activators were successfully prepared by the sol-gel method. The obtained sample shows an intense bluish-white emission (ranging from 350 to 600 nm, centered at 416 nm) under a wide range of UV light excitation (235-400 nm). The chromaticity coordinates of the sample are x = 0.159, y = 0.097, and the quantum yield is as high as 64.6%, which is a high value among the phosphor family without metal activators. The luminescent mechanisms have been ascribed to the carbon impurities in the Y2O3 host.