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RITVA LINDBERG GORAN SUNDHOLM JOHAN SJö BLOM PETRI AHONEN ESKO I. KAUPPINEN 《Journal of Dispersion Science and Technology》2013,34(1-2):715-722
The zeta-potentials of silica, copper, platinum and gold particles have been measured as a function of pH. The isoelectric points were found to be at pH 3.0, 5.8, 3.0 and 3.5, respectively. In the pH range 3.0 to 5.8 copper and silica particles are oppositely charged and accordingly the coating of silica with copper particles could be demonstrated. In the case of gold and platinum the sign of the charge is such that direct adhesion to silica particles cannot be expected and this was also demonstrated in the case of platinum. 相似文献
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van Enk SJ 《Physical review letters》2000,84(4):789; author reply 790
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Electron spin resonance (ESR), thermoluminescence and photoluminescence studies in Eu2+ activated Sr5(PO4)3Cl phosphor are reported in this paper. The Sr5(PO4)3Cl:Eu2+ phosphor is twice as sensitive as the conventional CaSO4:Dy phosphor used in thermoluminescence dosimetry of ionizing radiations. It has a linear response, simple glow curve, emission peaking at 456 nm. The defect centers formed in the Sr5(PO4)3Cl:Eu2+phosphor are studied by using the technique of ESR. A dominant TL glow peak at 430 K with a smaller shoulder at 410 K is observed in the phosphor. ESR studies indicate the presence at three centers at room temperature. Step annealing measurements show a connection between one of the centers and the dominant glow peak at 430 K. The 430 K TL peak is well correlated with center I, which is tentatively identified as (PO4)2− radical. 相似文献
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ZnS:Cu nanophosphors were prepared by wet chemical methods and characterized by X-ray diffraction (XRD). The typical morphologies of the nanophosphors were investigated by scanning electron microscopy (SEM). The thermoluminescence (TL) properties of inorganically and organically passivated ZnS:Cu nanophosphors were investigated after γ-irradiation using a 60Co source at room temperature. The TL glow curve of capped ZnS:Cu showed variation in TL peak and intensity as the capping agent was changed. Amongst the synthesized samples the TL glow curve of SiO2 capped ZnS:Cu showed the highest TL intensity. It has been found that TL response of SiO2 capped ZnS:Cu is linear in the range 10-550 Gy. A discussion of the obtained results is also presented. 相似文献
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In this paper we report the combustion synthesis of trivalent rare-earth (RE3+ = Dy, Eu and Ce) activated Sr4Al2O7 phosphor. The prepared phosphors were characterized by the X-ray powder diffraction (XRD) and photoluminescence (PL) techniques. Photoluminescence emission peaks of Sr4Al2O7:Dy3+ phosphor at 474 nm and 578 nm in the blue and yellow region of the spectrum. The prepared Eu3+ doped phosphors were excited by 395 nm then we found that the characteristics emission of europium ions at 615 nm (5D0?7F2) and 592 nm (5D0?7F1). Photoluminescence (PL) peaks situated at wavelengths of 363 and 378 nm in the UV region under excitation at around 326 nm in the Sr4Al2O7:Ce3+ phosphor. 相似文献
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Copper doped zinc sulfide nanoparticles were prepared by chemical precipitation method. The size of the particles was varied by changing the concentration of capping agent. The XRD studies indicate that most of the samples are cubic in nature. The broadening of peaks tends to increase with increasing capping agent concentration showing decrease in particle size. The crystalline size computed using Scherrer formula is found to be in range of 3–10 nm. Absorption spectra show absorption edge in UV region. The edge was found to shift towards shorter wavelength as the capping agent concentration is increased. This indicates increased effective band gap and hence reduced particle size. The nanoparticle size has been estimated in the range 5–10 nm using effective mass approximation model. For electroluminescence (EL) study of ZnS:Cu nanocrystals, the EL cells were prepared by placing ZnS:Cu nanoparticles between SnO2 coated conducting glass plate and aluminum foil. Alternating voltage of various frequencies was applied and EL brightness (B) at different voltages (V) was measured and reported in this paper. 相似文献
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Douglas McHugh Sherry SJ Hu Neta Rimmerman Ana Juknat Zvi Vogel J Michael Walker Heather B Bradshaw 《BMC neuroscience》2010,11(1):44
Background
Microglia provide continuous immune surveillance of the CNS and upon activation rapidly change phenotype to express receptors that respond to chemoattractants during CNS damage or infection. These activated microglia undergo directed migration towards affected tissue. Importantly, the molecular species of chemoattractant encountered determines if microglia respond with pro- or anti-inflammatory behaviour, yet the signaling molecules that trigger migration remain poorly understood. The endogenous cannabinoid system regulates microglial migration via CB2 receptors and an as yet unidentified GPCR termed the 'abnormal cannabidiol' (Abn-CBD) receptor. Abn-CBD is a synthetic isomer of the phytocannabinoid cannabidiol (CBD) and is inactive at CB1 or CB2 receptors, but functions as a selective agonist at this Gi/o-coupled GPCR. N-arachidonoyl glycine (NAGly) is an endogenous metabolite of the endocannabinoid anandamide and acts as an efficacious agonist at GPR18. Here, we investigate the relationship between NAGly, Abn-CBD, the unidentified 'Abn-CBD' receptor, GPR18, and BV-2 microglial migration. 相似文献10.
M. S. Atone S. J. Dhoble S. V. Moharil S. M. Dhopte P. L. Muthal V. K. Kondawar 《辐射效应与固体损伤》2013,168(2):225-230
Abstract Photoluminescence and thermoluminescence in BaSO4:Eu is reported. In earlier works, divalent Eu has been studied in BaSO4. In the present work Eu was incorporated as in predominantly Eu3+ or Eu2+ form. It is shown that RE3+ ? RE2+ conversion or RE2+ ? RE+ conversion is not an integral part of gamma induced TL. Eu3+ ? Eu2+ conversion, on the other hand, may be important in UV induced TL. Low UV efficiency of this material is attributed to poor Eu3+ ? Eu2+ conversion. This is in quite contrast to the analogus material CaSO4: Eu. 相似文献