Luminescence of Eu2+ in sodium polyaluminates

The sodium polyaluminates were synthesized by a high temperature solid state method and the luminescence of Eu2+ in the sodium polyaluminates was studied. The results show that the structure of the system Na1+xMgxAl11-xO17 from x=0.1 to x=1.0 belongs to Na-beta-alumina and the structure of the system Na1.67-2xBaxMg0.67Al10.33O17 changes at about x equal to 0.30, when x is smaller than 0.30 the system forms the solid solution structure of Na-beta-alumina, when x is larger than 0.30 the system becomes the ordered structure of Ba-beta-alumina, correspondingly the emission peak position and the relative emission intensity of Eu2+ change with the changes of composition and structure of the system. There exist two kinds of the luminescent centers of high and low energies of Eu2+ in the matrix of Na-beta-alumina structure. New phosphor with Ba-beta-alumina structure, Na0.67Ba0.50Mg0.67Al10.33O17:Eu2+, was obtained.

The spectral properties of BaB8O13:Eu,Tb phosphors

The luminescence properties of BaB8O13:xEu,yTb phosphors which were synthesized in air atmosphere have been studied. The emissions of europium(III), terbium(III) and europium(II) have been observed in BaB8O13:xEu, yTb phosphors. Electron paramagnetic resonance (EPR) studies were carried out. The intensities of EPR peaks of europium(II) are increased if terbium(III) is increased in BaB8O13:Eu3+,yTb(3+) phosphors. So the valence state of europium is influenced by terbium(III). These phenomena can be explained by an electron transfer mechanism. We found a new kind of method to prepare trichromatic phosphor that two rare earth ions activated in a BaB8O13 matrix.

Luminescence properties of SrB4O7: Eu, Tb phosphors

In this paper, the luminescence properties of SrB4O7: xEu, yTb phosphors were investigated. The SrB4O7: xEu, yTb phosphors were first synthesized in air atmosphere, and the emission spectra of Eu2+, Eu3+ and Tb3+ ions have been observed in phosphors. We found that the relative intensity of the emission of Eu2+ ion in the same matrix are increased when Tb3+ is incorporated in SrB4O7:Eu phosphor. So the valence state of europium is influenced by terbium. These phenomena can be explained using an electron transfer theory.

Electron transfer between Eu3+ and Tb3+ in BaB4O7 matrix

The BaB4O7:Eu, Tb phosphors are first synthesized in air atmosphere. We investigate their luminescent properties, and find that europium(II) and europium(III) can coexist in the BaB4O7:Eu phosphor. We observed that the relative intensity of europium(II) is increased when terbium(III) is incorporated. The electron spin resonance (ESR) spectra are carried out. The intensity of ESR peaks corresponding to europium(II) is also increased when terbium(III) is increased, so the valency state of europium is influenced by terbium(III). We explain these phenomena by an electron transfer mechanism. (C) 1996 Academic Press, Inc.

COMPARATIVE-STUDY OF CA4Y6(SIO4)(6)O-A PHOSPHORS PREPARED BY SOL-GEL AND DRY METHODS (A=PB2+,EU3+, TB3+,DY3+)

Ca4Y6(SiO4)(6)O:A (A = Pb2+, Eu3+, Tb3+, Dy3+) phosphors have been prepared by two methods: the sol-gel method and the conventional dry method. The crystallization processes and the luminescence characteristics of the phosphors were studied, The sol-gel method features low-temperature formation of the phosphor, leading to successful preparation of Pb2+-activated phosphors which could not be prepared by the dry method at high temperature. The (4f)(8-)(4f)(7)(5d)(1) absorption band of Tb3+ and the charge-transfer (CT) band of Eu3+ have higher energies and narrower half-widths in the sol-gel-derived phosphors than in the phosphors prepared by the dry method, respectively. The Tb3+ and Dy3+ ions show stronger emission in the former than in the latter. Both the yellow-to-blue intensity ratio (Y:B) of Dy3+ and the red-to-orange intensity ratio (R:O) of Eu3+ in the sol-gel-derived phosphors are smaller than those for the phosphors derived by the dry method.

含硫、磷壳聚糖新衍生物的制备、结构与抑菌活性关系研究

由于化学农药和抗生素兽药残留问题严重影响着环境和人类健康，生物农药和兽药的开发迫在眉睫。壳聚糖无毒、无污染、可生物降解，已经成为这一方向研究热点。但是，目前对壳聚糖抑菌活性的研究大都集中于分子量和脱乙酰度对其活性的影响，而对壳聚糖衍生物的研究相对较少。本文制备了壳聚糖磺酰胺类、酰基异硫氰酸酯类和α-氨基烷基膦酸酯类共计40余种新型壳聚糖含硫、磷衍生物，研究了它们对6种真菌（棉花枯萎病菌、番茄早疫病菌、葡萄炭疽病菌、姜叶斑点病菌、黄瓜灰霉病菌、芦笋茎枯病）和4种细菌（大肠杆菌、绿脓杆菌、金黄色葡萄球菌、八叠球菌）的抑菌活性，结果发现，所有衍生物的抑菌活性均强于壳聚糖原料，其中4种新型衍生物对于真菌具有较强抑制活性，其抑制率大于或接近阳性对照武夷菌素；10余种衍生物对于细菌有较强的杀菌、抑菌活性，如4-HBSA(l)CMCS、4-HBSA(l)CSS等对四种细菌具有广谱性，效果接近甚至强于阳性对照诺氟沙星。 对影响因素、构效关系和机理进行了深入探讨。衍生物的分子量、浓度、溶解性、α-位C原子空间位阻、吸电子空间诱导效应、烷基链的增长、等因素变化均会对抑菌活性产生重大影响。

Effects of diet and body size on phosphorus utilization of Liza haematocheila T. & S.

A 21-d laboratory experiment was conducted to study, the phosphorus (P) utilization of two different diets by redlip mullet Liza haematocheila T. & S. Sand-filtered water in salinity 30 and temperature 25 degrees C was used. Twenty-nine fish individuals were divided into three groups: 11 to group 1 (G1) fed on diet 1, 11 to group 2 (G2) fed on diet 2, and 7 to contrast group. Diet 1 was a commercial feed, more valuable in nutrition than diet 2 that similar to natural detritus. The results show the intake phosphorus (IP) of G1 was significantly higher than that of G2, and both increased linearly with body size at a certain amount of diet. The retention phosphorus (RP) in fish of G1 was lower than G2. The relationship between retention phosphorus and body size was positive and stronger in G2. Significant difference in faecal phosphorus (FP) was found between G1 and G2. Body size significantly impacted the excretion phosphorus (EP) in G1 but G2. The loss of intake phosphor-us in G1 was 10.83-20.27 mg per g fish weight gain, higher than that in G2 for 6.63-9.56. Of the phosphor-us, about 10% was allocated into growth, 50% in faeces, and the rest lost in excretion. The main part of phosphorus was lost in faeces but excretion. The phosphorus budget of the fish could be described as 100IP = 7.40RP + 47.39FP + 36.63EP (Diet 1) or 100IP = 11.93RP + 56.64FP + 21.76EP (Diet 2).

Transfer and transport of phosphorus and silica in the turbidity maximum zone of the Changjiang estuary

The concentration of suspended particulate matter (SPM), sedimentation flux, and various forms of phosphorus and silica in turbidity maximum zone (TMZ) in the Changjiang (Yangtze) estuary was studied. Based on the budget of P and Si, their mass balances in the TMZ were calculated. Results show that the variation in concentration of dissolved inorganic silicon (DISi) was mainly controlled by seawater dilution, while that of dissolved inorganic phosphor-us (DIP) was considerably affected by the buffering of suspended matter and sediment. Our experiments showed that the sedimentation fluxes of SPM and particulate inorganic phosphorus (PIP), total particulate phosphorus (TPP), particulate inorganic silicon (PISi), and biological silicon (BSi) in the TMZ were 238.4 g m(-2) d(-1) and 28.3, 43.1, 79.0, 63.0 mg m(-2) d(-1), respectively. In addition, a simple method to estimate the ratio of resuspension of sediment in the TMZ was established, with which the rate in surface and bottom waters of the TMZ accounted for 55.7 and 66.1% of the total SPM, respectively, indicating that the sediment resuspension in the TMZ influenced significantly the mass balances of P and Si. Particulate adsorbed P (60.8%) and 35.5% of total particulate P discharged from the river were filtered and then deposited in the TMZ. The input flux of PIP from the river mouth was 55.9% of that of DIP, being important as biologically available P, while that of PISi was only 3.5% of DISi, showing that particulate adsorbed Si was much less important than particulate adsorbed P. (c) 2008 Elsevier Ltd. All rights reserved.

Thomson spectrometer-microchannel plate assembly calibration for MeV-range positive and negative ions, and neutral atoms

We report on the absolute calibration of a microchannel plate (MCP) detector, used in conjunction with a Thomson parabola spectrometer. The calibration delivers the relation between a registered count numbers in the CCD camera (on which the MCP phosphor screen is imaged) and the number of ions incident on MCP. The particle response of the MCP is evaluated for positive, negative, and neutral particles at energies below 1 MeV. As the response of MCP depends on the energy and the species of the ions, the calibration is fundamental for the correct interpretation of the experimental results. The calibration method and arrangement exploits the unique emission symmetry of a specific source of fast ions and atoms driven by a high power laser.

A RG-II type polysaccharide purified from Aconitum coreanum and their anti-inflammatory activity

Korean mondshood root polysaccharides (KMPS) isolated from the root of Aconitum coreanum (Lévl.) Rapaics have shown anti-inflammatory activity, which is strongly influenced by their chemical structures and chain conformations. However, the mechanisms of the anti-inflammatory effect by these polysaccharides have yet to be elucidated. A RG-II polysaccharide (KMPS-2E, Mw 84.8 kDa) was isolated from KMPS and its chemical structure was characterized by FT-IR and NMR spectroscopy, gas chromatography–mass spectrometry and high-performance liquid chromatography. The backbone of KMPS-2E consisted of units of [→6) -β-D-Galp (1→3)-β-L-Rhap-(1→4)-β-D-GalpA-(1→3)-β-D-Galp-(1→] with the side chain →5)-β-D-Arap (1→3, 5)-β-D-Arap (1→ attached to the backbone through O-4 of (1→3,4)-L-Rhap. T-β-D-Galp is attached to the backbone through O-6 of (1→3,6)-β-D-Galp residues and T-β-D-Ara is connected to the end group of each chain. The anti-inflammatory effects of KMPS-2E and the underlying mechanisms using lipopolysaccharide (LPS) - stimulated RAW 264.7 macrophages and carrageenan-induced hind paw edema were investigated. KMPS-2E (50, 100 and 200 µg/mL) inhibits iNOS, TLR4, phospho-NF-κB–p65 expression, phosphor-IKK, phosphor-IκB-α expression as well as the degradation of IκB-α and the gene expression of inflammatory cytokines (TNF-α, IL-1β, iNOS and IL-6) mediated by the NF-κB signal pathways in macrophages. KMPS-2E also inhibited LPS-induced activation of NF-κB as assayed by electrophorectic mobility shift assay (EMSA) in a dose-dependent manner and it reduced NF-κB DNA binding affinity by 62.1% at 200µg/mL. In rats, KMPS-2E (200 mg/kg) can significantly inhibit carrageenan-induced paw edema as ibuprofen (200 mg/kg) within 3 h after a single oral dose. The results indicate that KMPS-2E is a promising herb-derived drug against acute inflammation.

Effect of Substrate Temperature on the Structural and Luminescent Characteristics of RF-Magnetron-Sputtered ZnGa2O4:Dy3+ Thin Films

ZnGa2O4:Dy3+ phosphor thin films were deposited on quartz substrates by radio frequency rf magnetron sputtering and the effect of substrate temperature on its structural and luminescent properties was investigated. Polycrystalline film could be deposited even at room temperature. The crystalline behavior, Zn/Ga ratio, and surface morphology of the films were found to be highly sensitive to substrate temperature. Under UV illumination, the as-deposited films at and above 300°C gave white luminescence even without any postdeposition treatments. The photoluminescent PL emission can be attributed to the combined effect of multicolor emissions from the single luminescence center Dy3+ via host-sensitization. Maximum PL emission intensity was observed for the film deposited at 600°C, and the CIE chromaticity coordinates of the emission were determined to be x,y = 0.34, 0.31 .

Electrical and Optical Properties of Znga2o4 Thin Films Deposited By Pulsed Laser Deposition

ZnGa2O4 spinel is a promising new UV transparent electronic conductor. Enhancing the electrical conductivity of this potential oxide phosphor can make it a promising transparent conducting oxide. In this paper, we have investigated the effects of processing and doping on the conductivity of semiconducting ZnGa2O4, particularly thin films. Crystalline zinc gallate thin films have been deposited on fused quartz substrates employing the pulsed laser deposition (PLD) technique at room temperature for an oxygen partial pressure of 0.1 Pa (0.001mbar). The films were found to be UV transparent, the band gap of which shifted to 4.75eV on hydrogen annealing. The band gap of the oxygen stoichiometric bulk powder samples (4.55eV) determined from diffuse reflection spectrum (DRS) shifted to 4.81eV on reduction in a hydrogen atmosphere. The electrical conductivity improved when Sn was incorporated into the ZnGa2O4 spinel. The conductivity of ZnGa2O4:Sn thin films was further improved on reduction.

A study of the white electroluminescence in ZnS:Cu,Pr,Cl phosphors

The method of preparation of ZnS phosphors doped with praseodymium and copper is given. The electroluminescence (EL) spectrum of ZnS:Pr,Cl has two broad bands at 470 and 570 nm. ZnS:Cu,Pr,Cl gives white emission with spectral peaks at 470, 520, 570 and 640 nm. The EL spectra of both types of phosphor exhibit a conspicuous colour shift as the frequency of the excitation voltage is varied. Detailed investigations show that the relative intensities of spectral peaks are strongly dependent on the frequency of the excitation voltage. The colour shift is explained on the basis of the Schon-Klasens model.

Luminescence studies of strontium sulphide based phosphors for display applications

This thesis has focused on the synthesis and analysis of some important phosphors (nano, bulk and thin film) for display applications. ACTFEL device with SrS:Cu as active layer was also fabricated.Three bulk phosphors: SrS:Cu,CI; SrS:Dy,Cl; and SrS:Dy,Cu,Cl were synthesized and their structural, optical and electrical properties were investigated. Special emphasis was given to, the analysis of the role of defects and charge compensating centers, on the structural changes of the host and hence the luminance. A new model describing the sensitizing behaviour of Cu in SrS:Dy,Cu,Cl two component phosphor was introduced. It was also found that addition of NH4CI as flux in SrS:Cu caused tremendous improvement in the structural and luminescence properties.A novel technique for ACTFEL phosphor deposition at low temperature was introduced. Polycrystalline films of SrS:Cu,F were synthesized at low temperature by concomitant evaporation of host and dopant by electron beam evaporation and thermal evaporatin methods.Copper doped strontium sulphide nanophosphor was synthesized for the first time. Improvement in the luminescence properties was observed in the nanophosphor with respect to it' s bulk counterpart.

Effect of Ce3+ Ion on the X-Ray Induced Fluorescence Emission from CaS

The effect of Ce3+ on the fluorescence emission from CaS:Ce3+ phosphor is studied using X-ray excitation. Apart from the emission in the visible region, the phosphor also shows fluorescence emission in the ultraviolet region. Variation in wavelengths and intensities of these emissions due to change in dopant concentration is also analysed.