Gravimetric method for the determination of diclofenac in pharmaceutical preparations.

Science.gov (United States)

Tubino, Matthieu; De Souza, Rafael L

2005-01-01

A gravimetric method for the determination of diclofenac in pharmaceutical preparations was developed. Diclofenac is precipitated from aqueous solution with copper(II) acetate in pH 5.3 (acetic acid/acetate buffer). Sample aliquots had approximately the same quantity of the drug content in tablets (50 mg) or in ampules (75 mg). The observed standard deviation was about +/- 2 mg; therefore, the relative standard deviation (RSD) was approximately 4% for tablet and 3% for ampule preparations. The results were compared with those obtained with the liquid chromatography method recommended in the United States Pharmacopoeia using the statistical Student's t-test. Complete agreement was observed. It is possible to obtain more precise results using higher aliquots, for example 200 mg, in which case the RSD falls to 1%. This gravimetric method, contrary to what is expected for this kind of procedure, is relatively fast and simple to perform. The main advantage is the absolute character of the gravimetric analysis.

Luminescence detection of shellfish

International Nuclear Information System (INIS)

Sanderson, D.C.W.; Carmichael, L.A.; Spencer, J.Q.; Naylor, J.D.

1996-01-01

The Scottish Universities Research and Reactor Centre (SURRC) has been active in the development and application of luminescence techniques in the detection of irradiated foods, in support of UK legislation. Thermoluminescence (TL), photostimulated luminescence (PSL) and photo-transfer luminescence (PTTL) are radiation-specific phenomena which arise due to energy stored by trapped charge carriers following irradiation. The energy released following stimulation is accompanied by detectable luminescence. The TL method involves preparation of pure silicate extracts from the sample and subsequent TL analysis, whereas PSL uses stimulation by electromagnetic radiation (visible, or near visible wavelengths) thus avoiding heating the sample. (author)

Analysis of the thermal profiles and the charcoal gravimetric yield in three variations of rectangular brick

Energy Technology Data Exchange (ETDEWEB)

Oliveira, Rogerio Lima Mota de; Alves Junior, Edson; Mulina, Bruno Henrique Oliveira; Borges, Valerio Luiz; Carvalho, Solidonio Rodrigues de [Federal University of Uberlandia - UFU, MG (Brazil). School of Mechanical Engineering - FEMEC], e-mails: rogerio@mecanica.ufu.br, edson@mec.ufu.br, vlborges@mecanica.ufu.br, srcarvalho@mecanica.ufu.br

2010-07-01

Charcoal assumes a major role in Brazilian economic scenario. The procedure for obtaining charcoal consists in carbonization of wood at certain specific temperatures in kilns. This ancient process has a few joined technologies and the kilns for such practice do not have any control instruments, in their great majority, becoming dependent on the ability of its operators. However, in recent decades several studies have been developed to improve the practice as well as the equipment that involve and control the stages of charcoal production. In this sense, this work proposes the analysis of the thermal profiles and the gravimetric yield in three variations of a rectangular brick kiln called RAC220: traditional (without any type of instrumentation), instrumented with thermal sensors (RTD PT100) and adapted with gasifier. The goal is to correlate temperature, gravimetric yield and quality of the produced charcoal. Immediate analyses were performed to determine the amount of fixed carbon, volatile gases and ashes contents in charcoal. Through such measurement procedures, together with statistical analysis, the aim is to identify an important tool to reduce the time of charcoal production and also contributes to minimize losses and to increase the thermal efficiency of the production process. (author)

Characterization and Gravimetric Analysis of the Dissolved Quartz in the Conversion of Coal Fly Ash to Sodalite

International Nuclear Information System (INIS)

Mohd Hilmi Mohamed; Zainab Ramli

2012-01-01

Coal fly ash (CFA) is a waste product produced from the electrical power plant and hazardous towards the environment. However, the high composition of silica and alumina in the CFA makes it useful as raw materials in the zeolite synthesis. However, the presence of silica in the form of quartz in the CFA does not facilitate the transformation of CFA to zeolite at 100 degree Celsius and autogeneous pressure. In this study, CFA was converted to zeolites in various NaOH concentrations by microwave heating at various heating time. All synthesized product were characterized by X-ray diffraction (XRD), and gravimetric analysis. XRD has shown that quite pure sodalite in nano size has been formed as early as 15 minutes and increase with time. Prolong heating up to 45 minutes has reduced the content of quartz to ca 20 %. Gravimetric analysis performed on the liquor of the reaction showed that the dissolved silica decrease with increase of heating time indicating that most of the dissolved quartz is used up to form sodalite framework. Hence, quartz of CFA did help in enhancing the crystallinity of the formed sodalite after prolong heating. (author)

Efficient green luminescence of terbium oxalate crystals: A case study with Judd-Ofelt theory and single crystal structure analysis and the effect of dehydration on luminescence

Science.gov (United States)

Alexander, Dinu; Joy, Monu; Thomas, Kukku; Sisira, S.; Biju, P. R.; Unnikrishnan, N. V.; Sudarsanakumar, C.; Ittyachen, M. A.; Joseph, Cyriac

2018-06-01

Design and synthesis of Lanthanide based metal organic framework is a frontier area of research owing to their structural diversity enabling specific applications. The luminescence properties of rare earths, tuned by the structural features of Ln-MOFs are investigated extensively. Rare earth oxalates which can be synthesized in a facile method, ensuring the structural features of MOFs with excellent photoluminescence characteristics deserves much attention. This work is the first time report on the single crystal structure and Judd-Ofelt (JO) theoretical analysis - their correlation with the intense and sharp green luminescence of Terbium oxalate crystals. The intense green luminescence observed for Terbium oxalate crystals for a wide range of excitation from DUV to visible region despite the luminescence limiting factors are discussed. The absence of concentration quenching and lifting up of forbidden nature of f-f transitions, allowing direct excitation of Terbium ions is analysed with the help of JO theory and single crystal structure analysis. The JO analysis predicted the asymmetry of Terbium sites, allowing the electric dipole transitions and from the JO intensity parameters, promising spectroscopic parameters - emission cross section, branching ratio, gain band width and gain coefficient of the material were calculated. The single crystal structure analysis revealed the asymmetry of Tb sites and structure of Terbium oxalate is formed by the hydrogen bonded stacking of overlapped six Terbium membered rings connected by the oxalate ligands. The molecularly thick layers thus formed on the crystal surface are imaged by the atomic force microscopy. The presence of water channels in the structure and the effect of lattice water molecules on the luminescence intensity are also investigated.

Quantitative analysis of time-resolved infrared stimulated luminescence in feldspars

DEFF Research Database (Denmark)

Pagonis, Vasilis; Ankjærgaard, Christina; Jain, Mayank

2016-01-01

Time-resolved infrared-stimulated luminescence (TR-IRSL) from feldspar samples is of importance in the field of luminescence dating, since it provides information on the luminescence mechanism in these materials. In this paper we present new analytical equations which can be used to analyze TR-IR...

Measurement of Gd content in (U,Gd)O2 using thermal gravimetric analysis

International Nuclear Information System (INIS)

Kim, Keon Sik; Yang, Jae Ho; Kang, Ki Won; Song, Kun Woo; Kim, Gil Moo

2004-01-01

We propose a simple and precise method for measuring the Gd content in the (U,Gd)O 2 pellet by only measuring the weight variation of the pellet during thermal heat treatment in air. The (U,Gd)O 2 fuel pellets were oxidized at 475 deg. C, subsequently heat treated at 1300 deg. C, and then cooled to room temperature in air. The accompanying weight variations were measured using thermo gravimetric analysis (TGA). The measured weight variations were mathematically analyzed with reference to the successive phase reactions during the heat treatment. This method provides an advantage in that the rare-earth element content including Gd can be measured using relatively simple equipment such as an electric furnace and a balance

Luminescence nanothermometry

Science.gov (United States)

Jaque, Daniel; Vetrone, Fiorenzo

2012-07-01

The current status of luminescence nanothermometry is reviewed in detail. Based on the main parameters of luminescence including intensity, bandwidth, bandshape, polarization, spectral shift and lifetime, we initially describe and compare the different classes of luminescence nanothermometry. Subsequently, the various luminescent materials used in each case are discussed and the mechanisms at the root of the luminescence thermal sensitivity are described. The most important results obtained in each case are summarized and the advantages and disadvantages of these approaches are discussed.The current status of luminescence nanothermometry is reviewed in detail. Based on the main parameters of luminescence including intensity, bandwidth, bandshape, polarization, spectral shift and lifetime, we initially describe and compare the different classes of luminescence nanothermometry. Subsequently, the various luminescent materials used in each case are discussed and the mechanisms at the root of the luminescence thermal sensitivity are described. The most important results obtained in each case are summarized and the advantages and disadvantages of these approaches are discussed. This work was supported by the Universidad Autónoma de Madrid and Comunidad Autónoma de Madrid (Project S2009/MAT-1756), by the Spanish Ministerio de Educacion y Ciencia (MAT2010-16161) and by Caja Madrid Foundation.

Analysis of art objects by means of ion beam induced luminescence

International Nuclear Information System (INIS)

Quaranta, A; Dran, J C; Salomon, J; Pivin, J C; Vomiero, A; Tonezzer, M; Maggioni, G; Carturan, S; Mea, G Della

2006-01-01

The impact of energetic ions on solid samples gives rise to the emission of visible light owing to the electronic excitation of intrinsic defects or extrinsic impurities. The intensity and position of the emission features provide information on the nature of the luminescence centers and on their chemical environments. This makes ion beam induced luminescence (IBIL) a useful complement to other ion beam analyses, like PIXE, in the cultural heritage field in characterizing the composition and the provenience of art objects. In the present paper, IBIL measurements have been performed on inorganic pigments for underlying the complementary role played by IBIL in the analysis of artistic works. Some blue and red pigment has been presented as case study

Quantitative analysis of time-resolved infrared stimulated luminescence in feldspars

Energy Technology Data Exchange (ETDEWEB)

Pagonis, Vasilis, E-mail: vpagonis@mcdaniel.edu [McDaniel College, Physics Department, Westminster, MD 21157 (United States); Ankjærgaard, Christina [Soil Geography and Landscape Group & Netherlands Centre for Luminescence dating, Wageningen University, PO Box 47, 6700 AA Wageningen (Netherlands); Jain, Mayank [Center for Nuclear Technologies, Technical University of Denmark, DTU Risø Campus, Roskilde (Denmark); Chithambo, Makaiko L. [Department of Physics and Electronics, Rhodes University, PO BOX 94, Grahamstown 6140 (South Africa)

2016-09-15

Time-resolved infrared-stimulated luminescence (TR-IRSL) from feldspar samples is of importance in the field of luminescence dating, since it provides information on the luminescence mechanism in these materials. In this paper we present new analytical equations which can be used to analyze TR-IRSL signals, both during and after short infrared stimulation pulses. The equations are developed using a recently proposed kinetic model, which describes localized electronic recombination via tunneling between trapped electrons and recombination centers in luminescent materials. Recombination is assumed to take place from the excited state of the trapped electron to the nearest-neighbor center within a random distribution of luminescence recombination centers. Different possibilities are examined within the model, depending on the relative importance of electron de-excitation and recombination. The equations are applied to experimental TR-IRSL data of natural feldspars, and good agreement is found between experimental and modeling results.

Tandem Gravimetric and Volumetric Apparatus for Methane Sorption Measurements

Science.gov (United States)

Burress, Jacob; Bethea, Donald

Concerns about global climate change have driven the search for alternative fuels. Natural gas (NG, methane) is a cleaner fuel than gasoline and abundantly available due to hydraulic fracturing. One hurdle to the adoption of NG vehicles is the bulky cylindrical storage vessels needed to store the NG at high pressures (3600 psi, 250 bar). The adsorption of methane in microporous materials can store large amounts of methane at low enough pressures for the allowance of conformable, ``flat'' pressure vessels. The measurement of the amount of gas stored in sorbent materials is typically done by measuring pressure differences (volumetric, manometric) or masses (gravimetric). Volumetric instruments of the Sievert type have uncertainties that compound with each additional measurement. Therefore, the highest-pressure measurement has the largest uncertainty. Gravimetric instruments don't have that drawback, but can have issues with buoyancy corrections. An instrument will be presented with which methane adsorption measurements can be performed using both volumetric and gravimetric methods in tandem. The gravimetric method presented has no buoyancy corrections and low uncertainty. Therefore, the gravimetric measurements can be performed throughout an entire isotherm or just at the extrema to verify the results from the volumetric measurements. Results from methane sorption measurements on an activated carbon (MSC-30) and a metal-organic framework (Cu-BTC, HKUST-1, MOF-199) will be shown. New recommendations for calculations of gas uptake and uncertainty measurements will be discussed.

Analysis of luminescence from common salt (NaCl) for application to retrospective dosimetry

International Nuclear Information System (INIS)

Spooner, N.A.; Smith, B.W.; Williams, O.M.; Creighton, D.F.; McCulloch, I.; Hunter, P.G.; Questiaux, D.G.; Prescott, J.R.

2011-01-01

Thermoluminescence (TL), Optically-Stimulated Luminescence (OSL) and Infrared-Stimulated Luminescence (IRSL) emitted from a set of 19 salt (NaCl) samples were studied for potential application to retrospective dosimetry. TL emission spectra revealed intense TL emissions from most samples, centred on 590 nm; UV and blue emissions were also found. Significant thermally-induced sensitivity changes were observed and TL, OSL and IRSL growth curves were measured. Pulse anneal analysis was performed, as was quantitative imaging of the TL, OSL and IRSL to assess sample heterogeneity. Kinetic analysis found lifetimes at 20 °C of the 200 °C and 240 °C TL peaks to be 0.6 ka and 4 ka respectively; sufficient for application to retrospective dosimetry.

Synthesis of in-situ luminescent ZnS nanoparticles facile with CTAB micelles and their properties study

Energy Technology Data Exchange (ETDEWEB)

Shukla, Vaishali [Centre for Nanoscience, Central University of Gujarat, Gandhinagar (India); Singh, Man [School of Chemical Sciences, Central University of Gujarat, Gandhinagar, India Telephone: 079-23260210, fax: 079-23260076 (India)

2016-04-13

Currently, the development of micelles route is thrust area of research in nanoscience for the control particle size and remarkable properties through chemical co-precipitation method. A 0.9 mM aqueous CTAB micellar solution plays a role as capping agent in the homogeneous solution of 0.5 M ZnSO{sub 4} and 0.5 M Na{sub 2}S for synthesis, further precipitates purified with centrifugation in cold ethanol and millipore water to remove unreacted reagents and ionic salt particles. A resultant, white colored luminescent ZnS nanoparticle out with ∼95% yield is reported. The ZnS nanoparticles have been examined by their luminescence properties, optical properties and crystal structure. The mean particle size of ZnS nanoparticles is found to be ∼10 nm in various technical results and UV-absorption was 80 nm blue shifts moved from 345 nm (bulk material) to 265 nm, showing a quantum size impact. The X-ray diffraction (XRD) pattern shows the immaculate cubic phase. Photoluminescence (PL) investigates the recombination mechanism with blue emission from shallow electron traps at 490 nm in ZnS nanoparticles. An FTIR spectrum and Thermal gravimetric analysis (TGA) gives confirmation of CTAB – cationic surfactant on surface of ZnS nanoparticle as capping agent as well thermal stability of CTAB capped ZnS nanoparticles with respect to temperature.

Quantitative analysis of time-resolved infrared stimulated luminescence in feldspars

DEFF Research Database (Denmark)

Pagonis, Vasilis; Ankjærgaard, Christina; Jain, Mayank

2016-01-01

Time-resolved infrared-stimulated luminescence (TR-IRSL) from feldspar samples is of importance in the field of luminescence dating, since it provides information on the luminescence mechanism in these materials. In this paper we present new analytical equations which can be used to analyze TR-IR....... The equations are applied to experimental TR-IRSL data of natural feldspars, and good agreement is found between experimental and modeling results....

Gravimetric determination of beryllium in the presence of transition metals

International Nuclear Information System (INIS)

Morozova, S.S.; Nikitina, L.V.; Dyatlova, N.M.; Serebryakova, G.V.; Vol'nyagina, A.N.

1976-01-01

A new organic reagent, nitrolotrimethylphosphonic acid (H 6 L), is proposed for gravimetric determination of beryllium. This complexone forms with Be hardly soluble complexes in a wide pH range. The separated complex has a composition Be 5 (HL) 2 x10H 2 O. To elucidate the possibility of determining Be in the presence of transition metals, often accompanying beryllium in alloys, interaction of cations of these metals with H 6 L at different pH has been studied potentiometrically. It has been established that at pH=1.1 in the presence of masking reagent (diethylentriaminopentacetic acid) Be can be determined when zinc, copper, chromium, cobalt, nickel, iron, manganese and cadmium are present. Gravimetric method of determining Be with the help of H 6 L has been developed. The weight form is obtained by drying the precipitate which reduces considerably the time of analysis and the error of determination

A Comparative Analysis of Seismological and Gravimetric Crustal Thicknesses below the Andean Region with Flat Subduction of the Nazca Plate

Directory of Open Access Journals (Sweden)

Mario E. Gimenez

2009-01-01

Full Text Available A gravimetric study was carried out in a region of the Central Andean Range between 28∘ and 32∘ south latitudes and from 72∘ and 66∘ west longitudes. The seismological and gravimetrical Moho models were compared in a sector which coincides with the seismological stations of the CHARGE project. The comparison reveals discrepancies between the gravity Moho depths and those obtained from seismological investigations (CHARGE project, the latter giving deeper values than those resulting from the gravimetric inversion. These discrepancies are attenuated when the positive gravimetric effect of the Nazca plate is considered. Nonetheless, a small residuum of about 5 km remains beneath the Cuyania terrane region, to the east of the main Andean chain. This residuum could be gravimetrically justified if the existence of a high density or eclogitized portion of the lower crust is considered. This result differed from the interpretations from Project “CHARGE” which revealed that the entire inferior crust extending from the Precordillera to the occidental “Sierras Pampeanas” could be “eclogitized”. In this same sector, we calculated the effective elastic thickness (Te of the crust. These results indicated an anomalous value of Te = 30 km below the Cuyania terrane. This is further conclusive evidence of the fact that the Cuyania terrane is allochthonous, for which also geological evidences exist.

Comparison of gravimetric, creamatocrit and esterified fatty acid methods for determination of total fat content in human milk.

Science.gov (United States)

Du, Jian; Gay, Melvin C L; Lai, Ching Tat; Trengove, Robert D; Hartmann, Peter E; Geddes, Donna T

2017-02-15

The gravimetric method is considered the gold standard for measuring the fat content of human milk. However, it is labor intensive and requires large volumes of human milk. Other methods, such as creamatocrit and esterified fatty acid assay (EFA), have also been used widely in fat analysis. However, these methods have not been compared concurrently with the gravimetric method. Comparison of the three methods was conducted with human milk of varying fat content. Correlations between these methods were high (r(2)=0.99). Statistical differences (Pmethods. Overall, stronger correlation with lower mean (4.73g/L) and percentage differences (5.16%) was observed with the creamatocrit than the EFA method when compared to the gravimetric method. Furthermore, the ease of operation and real-time analysis make the creamatocrit method preferable. Copyright © 2016. Published by Elsevier Ltd.

Zirconium determination in refractories (gravimetric method)

International Nuclear Information System (INIS)

Capiotto, N.; Narahashi, Y.; Perish, C.G.; Souza, J.R.

1991-01-01

The zirconium determination in refractories is described, consisting in two separation methods for eliminating the interferences. The formatted product is calcined at 1100 0 C and determined gravimetrically as Zr P z 07. (author)

Luminescence in medical image science

Energy Technology Data Exchange (ETDEWEB)

Kandarakis, I.S., E-mail: kandarakis@teiath.gr

2016-01-15

Radiation detection in Medical Imaging is mostly based on the use of luminescent materials (scintillators and phosphors) coupled to optical sensors. Materials are employed in the form of granular screens, structured (needle-like) crystals and single crystal transparent blocks. Storage phosphors are also incorporated in some x-ray imaging plates. Description of detector performance is currently based on quality metrics, such as the Luminescence efficiency, the Modulation Transfer Function (MTF), the Noise Power Spectrum (NPS) and the Detective Quantum Efficiency (DQE) can be defined and evaluated. The aforementioned metrics are experimental evaluated for various materials in the form of screens. A software was designed (MINORE v1) to present image quality measurements in a graphical user interface (GUI) environment. Luminescence efficiency, signal and noise analysis are valuable tools for the evaluation of luminescent materials as candidates for medical imaging detectors. - Highlights: • Luminescence based medical imaging detectors. • Image science: MTF, NPS, DQE. • Phosphors screens light emission efficiency experimental evaluation. • Theoretical models for estimation of phosphor screen properties. • Software for medical image quality metrics.

Silica- and silylated europium-based luminescent hybrids: new analysis tools for biological environments

International Nuclear Information System (INIS)

Pereira Duarte, Adriana

2012-01-01

The association of the very interesting luminescence properties of the lanthanide chelates with the physicochemical properties of inorganic matrix such as silica is a promising way to obtain new probes or luminescent markers for biology analyses. In this idea, this work focuses on the preparation of new hybrid materials based on the grafting of new europium(III) complexes on silica nanoparticles. These europium complexes were developed in our group using bifunctional ligands containing both complexing and grafting sites. Intrinsic characteristic of the ligands gives us the ability to make a covalent bond between the material surface and the complex. Two different methodologies were used; the first one is the direct grafting reaction involving the complex and silica nanoparticles (i.e. dense or meso-porous particles). The second one is the Stoeber reaction, where the SiO 2 nanoparticles were prepared in presence of the europium complex. The last methodology has an additional difficult, because of the presence of silylated europium complex, it needs a closer control of the physicochemical conditions. The new organic-inorganic hybrid materials, obtained in this work, present an interesting luminescence behavior and this one is depending on the localization of the europium complex, i.e. on the surface or within the nanoparticles. In addition, the obtained hybrids present the nano-metric dimension and the complex is not leachable. Analyses were realized to describe the luminescence properties, beyond surface and structural characteristics. Initial results show that the new hybrids are promising candidates for luminescent bio-markers, particularly for the time-resolved analysis. (author) [fr

Uranyl fluoride luminescence in acidic aqueous solutions

International Nuclear Information System (INIS)

Beitz, J.V.; Williams, C.W.

1996-01-01

Luminescence emission spectra and decay rates are reported for uranyl species in acidic aqueous solutions containing HF or added NaF. The longest luminescence lifetime, 0.269 ± 0.006 ms, was observed from uranyl in 1 M HF + 1 M HClO 4 at 296 K and decreased with increasing temperature. Based on a luminescence dynamics model that assumes equilibrium among electronically excited uranyl fluoride species and free fluoride ion, this long lived uranyl luminescence in aqueous solution is attributed primarily to UO 2 F 2 . Studies on the effect of added LiNO 3 or Na 2 WO 4 ·2H 2 O showed relatively weak quenching of uranyl fluoride luminescence which suggests that high sensitivity determination of the UF 6 content of WF 6 gas should be feasible via uranyl luminescence analysis of hydrolyzed gas samples of impure WF 6

Novel gravimetric measurement technique for quantitative volume calibration in the sub-microliter range

International Nuclear Information System (INIS)

Liang, Dong; Zengerle, Roland; Steinert, Chris; Ernst, Andreas; Koltay, Peter; Bammesberger, Stefan; Tanguy, Laurent

2013-01-01

We present a novel measurement method based on the gravimetric principles adapted from the ASTM E542 and ISO 4787 standards for quantitative volume determination in the sub-microliter range. Such a method is particularly important for the calibration of non-contact micro dispensers as well as other microfluidic devices. The novel method is based on the linear regression analysis of continuously monitored gravimetric results and therefore is referred to as ‘gravimetric regression method (GRM)’. In this context, the regression analysis is necessary to compensate the mass loss due to evaporation that is significant for very small dispensing volumes. A full assessment of the measurement uncertainty of GRM is presented and results in a standard measurement uncertainty around 6 nl for dosage volumes in the range from 40 nl to 1 µl. The GRM has been experimentally benchmarked with a dual-dye ratiometric photometric method (Artel Inc., Westbrook, ME, USA), which can provide traceability of measurement to the International System of Units (SI) through reference standards maintained by NIST. Good precision (max. CV = 2.8%) and consistency (bias around 7 nl in the volume range from 40 to 400 nl) have been observed comparing the two methods. Based on the ASTM and ISO standards on the one hand and the benchmark with the photometric method on the other hand, two different approaches for establishing traceability for the GRM are discussed. (paper)

Providing long-term trend and gravimetric factor at Chandler period from superconducting gravimeter records by using Singular Spectrum Analysis along with its multivariate extension

Science.gov (United States)

Gruszczynska, M.; Rosat, S.; Klos, A.; Bogusz, J.

2017-12-01

In this study, Singular Spectrum Analysis (SSA) along with its multivariate extension MSSA (Multichannel SSA) were used to estimate long-term trend and gravimetric factor at the Chandler wobble frequency from superconducting gravimeter (SG) records. We have used data from seven stations located worldwide and contributing to the International Geodynamics and Earth Tides Service (IGETS). The timespan ranged from 15 to 19 years. Before applying SSA and MSSA, we had removed local tides, atmospheric (ECMWF data), hydrological (MERRA2 products) loadings and non-tidal ocean loading (ECCO2 products) effects. In the first part of analysis, we used the SSA approach in order to estimate the long-term trends from SG observations. We use the technique based on the classical Karhunen-Loève spectral decomposition of time series into long-term trend, oscillations and noise. In the second part, we present the determination of common time-varying pole tide (annual and Chandler wobble) to estimate gravimetric factor from SG time series using the MSSA approach. The presented method takes advantage over traditional methods like Least Squares Estimation by determining common modes of variability which reflect common geophysical field. We adopted a 6-year lag-window as the optimal length to extract common seasonal signals and the Chandler components of the Earth polar motion. The signals characterized by annual and Chandler wobble account for approximately 62% of the total variance of residual SG data. Then, we estimated the amplitude factors and phase lags of Chandler wobble with respect to the IERS (International Earth Rotation and Reference Systems Service) polar motion observations. The resulting gravimetric factors at the Chandler Wobble period are finally compared with previously estimates. A robust estimate of the gravimetric Earth response to the Chandlerian component of the polar motion is required to better constrain the mantle anelasticity at this frequency and hence the

Gravimetric gas determinations for volume calibration

International Nuclear Information System (INIS)

Gibbs, P.W.

1991-01-01

Gravimetric measurements of gases is one of the methods available for calibrating gas volumes. By inputting a known quantity of gas and measuring the resulting pressure and temperature, the system volume can be calculated using gas law principles. Historically, this method has been less accurate due to the difficulty in the mass determination. This difficulty comes from several sources. Two examples are the large tare weight of the gas container relative to the weight of gas and the external volume of the gas container relative to the standards. The application of a gravimetric gas determination to tank volume calibrations at the savannah River Site is discussed. Mass determinations on a 25,00 gram gas container were such that a 1500 gram quantity of gas was routinely determined to within ±0.2 gram at the 99% confidence level. In this paper the weighting design and the methods used to address the difficulties of the mass determination are detailed

Uncertainty Quantification and Global Sensitivity Analysis of Subsurface Flow Parameters to Gravimetric Variations During Pumping Tests in Unconfined Aquifers

Science.gov (United States)

Maina, Fadji Zaouna; Guadagnini, Alberto

2018-01-01

We study the contribution of typically uncertain subsurface flow parameters to gravity changes that can be recorded during pumping tests in unconfined aquifers. We do so in the framework of a Global Sensitivity Analysis and quantify the effects of uncertainty of such parameters on the first four statistical moments of the probability distribution of gravimetric variations induced by the operation of the well. System parameters are grouped into two main categories, respectively, governing groundwater flow in the unsaturated and saturated portions of the domain. We ground our work on the three-dimensional analytical model proposed by Mishra and Neuman (2011), which fully takes into account the richness of the physical process taking place across the unsaturated and saturated zones and storage effects in a finite radius pumping well. The relative influence of model parameter uncertainties on drawdown, moisture content, and gravity changes are quantified through (a) the Sobol' indices, derived from a classical decomposition of variance and (b) recently developed indices quantifying the relative contribution of each uncertain model parameter to the (ensemble) mean, skewness, and kurtosis of the model output. Our results document (i) the importance of the effects of the parameters governing the unsaturated flow dynamics on the mean and variance of local drawdown and gravity changes; (ii) the marked sensitivity (as expressed in terms of the statistical moments analyzed) of gravity changes to the employed water retention curve model parameter, specific yield, and storage, and (iii) the influential role of hydraulic conductivity of the unsaturated and saturated zones to the skewness and kurtosis of gravimetric variation distributions. The observed temporal dynamics of the strength of the relative contribution of system parameters to gravimetric variations suggest that gravity data have a clear potential to provide useful information for estimating the key hydraulic

Comparison of Potentiometric and Gravimetric Methods for Determination of O/U Ratio

International Nuclear Information System (INIS)

Farida; Windaryati, L; Putro Kasino, P

1998-01-01

Comparison of determination O/U ratio by using potentiometric and gravimetric methods has been done. Those methods are simple, economical and having high precision and accuracy. Determination O/U ratio for UO 2 powder using potentiometric is carried out by adopting the davies-gray method. This technique is based on the redox reaction of uranium species such as U(IV) and U(VI). In gravimetric method,the UO 2 power as a sample is calcined at temperature of 900 C, and the weight of the sample is measured after calcination process. The t-student test show that there are no different result significantly between those methods. However, for low concentration in the sample the potentiometric method has a highed precision and accuracy compare to the gravimetric method. O/U ratio obtained is 2.00768 ± 0,00170 for potentiometric method 2.01089 ± 0,02395 for gravimetric method

Luminescence dating

International Nuclear Information System (INIS)

Rieser, U.

2013-01-01

The luminescence techniques have evolved over the last 40 years to a powerful dating instrument in archaeology and geoscience. Depending on how the luminescence is stimulated, one distinguishes the phenomena of thermoluminescence (TL), optically stimulated luminescence (OSL) and infrared stimulated luminescence (IRSL). Each of these phenomena has its specific potential for dating various archaeological materials in the time range from medieval back to palaeolithic periods, or, speaking in geological terms, for dating of Holocene and late Pleistocene objects. The OSL and IRSL techniques are sometimes treated together as 'optical dating'. The luminescence techniques differ from other major dating techniques, such as 14 C, essentially by their applicability to inorganic materials, their wide age-range from about 100 years to more than 100,000 years and the kind of datable events which are the last exposure to heat or to light. (author). 10 refs., 3 figs.

Luminescence dating

International Nuclear Information System (INIS)

Rieser, U.

2009-01-01

The luminescence techniques have evolved over the last 40 years to a powerful dating instrument in archaeology and geoscience. Depending on how the luminescence is stimulated, one distinguishes the phenomena of thermoluminescence (TL), optically stimulated luminescence (OSL) and infrared stimulated luminescence (IRSL). Each of these phenomena has its specific potential for dating various archaeological materals in the time range from medieval back to palaeolithic periods, or, speaking in geological terms, for dating of Holocene and late Pleistocene objects. The OSL and IRSL techniques are sometimes treated together as 'optical dating'. The luminescence techniques differ from other major dating techniques, such as 14 C, essentially by their applicability to inorganic materials, their wide age-range from about 100 years to more than 100,000 years and the kind of datable events which are the last exposure to heat or to light. (author). 10 refs., 3 figs.

Luminescence dating

International Nuclear Information System (INIS)

Rieser, U.

2008-01-01

The luminescence techniques have evolved over the last 40 years to a powerful dating instrument in archaeology and geoscience. Depending on how the luminescence is stimulated, one distinguishes the phenomena of thermoluminescence (TL), optically stimulated luminescence (OSL) and infrared stimulated luminescence (IRSL). Each of these phenomena has its specific potential for dating various archaeological materals in the time range from medieval back to palaeolithic periods, or, speaking in geological terms, for dating of Holocene and late Pleistocene objects. The OSL and IRSL techniques are sometimes treated together as 'optical dating'. The luminescence techniques differ from other major dating techniques, such as 14 C, essentially by their applicability to inorganic materials, their wide age-range from about 100 years to more than 100,000 years and the kind of datable events which are the last exposure to heat or to light. (author). 10 refs., 3 figs

Luminescence dating

International Nuclear Information System (INIS)

Rieser, U.

2012-01-01

The luminescence techniques have evolved over the last 40 years to a powerful dating instrument in archaeology and geoscience. Depending on how the luminescence is stimulated, one distinguishes the phenomena of thermoluminescence (TL), optically stimulated luminescence (OSL) and infrared stimulated luminescence (IRSL). Each of these phenomena has its specific potential for dating various archaeological materials in the time range from medieval back to palaeolithic periods, or, speaking in geological terms, for dating of Holocene and late Pleistocene objects. The OSL and IRSL techniques are sometimes treated together as 'optical dating'. The luminescence techniques differ from other major dating techniques, such as 14 C, essentially by their applicability to inorganic materials, their wide age-range from about 100 years to more than 100,000 years and the kind of datable events which are the last exposure to heat or to light. (author). 10 refs., 3 figs.

Luminescence dating

International Nuclear Information System (INIS)

Rieser, U.

2009-01-01

The luminescence techniques have evolved over the last 40 years to a powerful dating instrument in archaeology and geoscience. Depending on how the luminescence is stimulated, one distinguishes the phenomena of thermoluminescence (TL), optically stimulated luminescence (OSL) and infrared stimulated luminescence (IRSL). Each of these phenomena has its specific potential for dating various archaeological materals in the time range from medieval back to palaeolithic periods, or, speaking in geological terms, for dating of Holocene and late Pleistocene objects. The OSL and IRSL techniques are sometimes treated together as 'optical dating'. The luminescence techniques differ from other major dating techniques, such as 14 C, essentially by their applicability to inorganic materials, their wide age-range from about 100 years to more than 100,000 years and the kind of datable events which are the last exposure to heat or to light. (author). 10 refs., 3 figs

Gravimetric Analysis of Bismuth in Bismuth Subsalicylate Tablets: A Versatile Quantitative Experiment for Undergraduate Laboratories

Science.gov (United States)

Davis, Eric; Cheung, Ken; Pauls, Steve; Dick, Jonathan; Roth, Elijah; Zalewski, Nicole; Veldhuizen, Christopher; Coeler, Joel

2015-01-01

In this laboratory experiment, lower- and upper-division students dissolved bismuth subsalicylate tablets in acid and precipitated the resultant Bi[superscript 3+] in solution with sodium phosphate for a gravimetric determination of bismuth subsalicylate in the tablets. With a labeled concentration of 262 mg/tablet, the combined data from three…

Combination volumetric and gravimetric sorption instrument for high accuracy measurements of methane adsorption

Science.gov (United States)

Burress, Jacob; Bethea, Donald; Troub, Brandon

2017-05-01

The accurate measurement of adsorbed gas up to high pressures (˜100 bars) is critical for the development of new materials for adsorbed gas storage. The typical Sievert-type volumetric method introduces accumulating errors that can become large at maximum pressures. Alternatively, gravimetric methods employing microbalances require careful buoyancy corrections. In this paper, we present a combination gravimetric and volumetric system for methane sorption measurements on samples between ˜0.5 and 1 g. The gravimetric method described requires no buoyancy corrections. The tandem use of the gravimetric method allows for a check on the highest uncertainty volumetric measurements. The sources and proper calculation of uncertainties are discussed. Results from methane measurements on activated carbon MSC-30 and metal-organic framework HKUST-1 are compared across methods and within the literature.

Luminescence and energy transfer

Energy Technology Data Exchange (ETDEWEB)

Blasse, G; Bleijenberg, K C; Powell, R C

1980-01-01

This paper deals with the luminescence of uranate centres in solids. The luminescence properties are influenced by the coordination number of the hexavalent uranium ion and by the crystallographic surroundings of the uranate centre. Transitions playing a role in the luminescence processes within the octahedral UO/sub 6//sup 6 -/ group are discussed using the results from both theoretical and experimental studies on another octahedral uranium complex: UF/sub 6/. The luminescence of the octahedral uranate group in oxidic compounds is discussed. Attention is paid to the vibrational structure, which is observed in the luminescence spectra at low temperatures and to the temperature quenching of the luminescence. The temperature quenching of the uranate luminescence in uranium-doped tungstates with ordered perovskite structure can be described in terms of a three state single configurational coordinate diagram. The complicated luminescence spectra of uranium-activated sodium fluoride (NaF-U) crystals have been unraveled using chemical variation of the crystal compositions and using site selective laser excitation techniques. Four different luminescent uranate centres have been observed in NaF-U. A model for the configurations of the luminescent centres has been deduced using the results from ionic conductivity experiments.

Mycotoxin metrology: Gravimetric production of zearalenone calibration solution

Science.gov (United States)

Rego, E. C. P.; Simon, M. E.; Li, Xiuqin; Li, Xiaomin; Daireaux, A.; Choteau, T.; Westwood, S.; Josephs, R. D.; Wielgosz, R. I.; Cunha, V. S.

2018-03-01

Food safety is a major concern for countries developing metrology and quality assurance systems, including the contamination of food and feed by mycotoxins. To improve the mycotoxin analysis and ensure the metrological traceability, CRM of calibration solution should be used. The production of certified mycotoxin solutions is a major challenge due to the limited amount of standard for conducting a proper purity study and due to the cost of standards. The CBKT project was started at BIPM and Inmetro produced gravimetrically one batch of zearelenone in acetronitrile (14.708 ± 0.016 μg/g, k=2) and conducted homogeneity, stability and value assignment studies.

WellReader: a MATLAB program for the analysis of fluorescence and luminescence reporter gene data.

Science.gov (United States)

Boyer, Frédéric; Besson, Bruno; Baptist, Guillaume; Izard, Jérôme; Pinel, Corinne; Ropers, Delphine; Geiselmann, Johannes; de Jong, Hidde

2010-05-01

Fluorescent and luminescent reporter gene systems in combination with automated microplate readers allow real-time monitoring of gene expression on the population level at high precision and sampling density. This generates large amounts of data for the analysis of which computer tools are missing to date. We have developed WellReader, a MATLAB program for the analysis of fluorescent and luminescent reporter gene data. WellReader allows the user to load the output files of microplate readers, remove outliers, correct for background effects and smooth and fit the data. Moreover, it computes biologically relevant quantities from the measured signals, notably promoter activities and protein concentrations, and compares the resulting expression profiles of different genes under different conditions. WellReader is available under a LGPL licence at http://prabi1.inrialpes.fr/trac/wellreader.

Development of an ultralow-light-level luminescence image analysis system for dynamic measurements of transcriptional activity in living and migrating cells.

Science.gov (United States)

Maire, E; Lelièvre, E; Brau, D; Lyons, A; Woodward, M; Fafeur, V; Vandenbunder, B

2000-04-10

We have developed an approach to study in single living epithelial cells both cell migration and transcriptional activation, which was evidenced by the detection of luminescence emission from cells transfected with luciferase reporter vectors. The image acquisition chain consists of an epifluorescence inverted microscope, connected to an ultralow-light-level photon-counting camera and an image-acquisition card associated to specialized image analysis software running on a PC computer. Using a simple method based on a thin calibrated light source, the image acquisition chain has been optimized following comparisons of the performance of microscopy objectives and photon-counting cameras designed to observe luminescence. This setup allows us to measure by image analysis the luminescent light emitted by individual cells stably expressing a luciferase reporter vector. The sensitivity of the camera was adjusted to a high value, which required the use of a segmentation algorithm to eliminate the background noise. Following mathematical morphology treatments, kinetic changes of luminescent sources were analyzed and then correlated with the distance and speed of migration. Our results highlight the usefulness of our image acquisition chain and mathematical morphology software to quantify the kinetics of luminescence changes in migrating cells.

A detailed gravimetric geoid from North America to Eurasia

Science.gov (United States)

Vincent, S. F.; Strange, W. E.; Marsh, J. G.

1972-01-01

A detailed gravimetric geoid of the United States, North Atlantic, and Eurasia, which was computed from a combination of satellite derived and surface gravity data, is presented. The precision of this detailed geoid is + or - 2 to + or - 3 m in the continents but may be in the range of 5 to 7 m in those areas where data is sparse. Comparisons of the detailed gravimetric geoid with results of Rapp, Fischer, and Rice for the United States, Bomford in Europe, and Heiskanen and Fischer in India are presented. Comparisons are also presented with geoid heights from satellite solutions for geocentric station coordinates in North America, the Caribbean, and Europe.

Combined Colorimetric and Gravimetric CMUT Sensor for Detection of Phenylacetone

DEFF Research Database (Denmark)

Mølgaard, Mathias Johannes Grøndahl; Laustsen, Milan; Thygesen, Ida Lysgaard

2017-01-01

The detection of phenylacetone is of interest as it is a common precursor for the synthesis of (meth)amphetamine. Resonant gravimetric sensors can be used to detect the mass and hereby the concentration of a gas while colorimetric arrays typically have an exceptional selectivity to the target...... analyte if the right colorimetric dyes are chosen. We present a sensor system consisting of a Capacitive Micromachined Ultrasonic Transducer (CMUT) and a colorimetric array for detection of phenylacetone. The CMUT is used as a resonant gravimetric gas sensor where the resonance frequency shift due to mass...

Modified method for zirconium or hafnium gravimetric determination with glycolic acid derivatives

International Nuclear Information System (INIS)

Barbieri, R.S.; Rocha, J.C.; Terra, V.R.; Marques Neto, A.

1989-01-01

The conditions for gravimetric determination of zirconium or hafnium by glicolic acid derivatives were studied by thermogravimetric analysis. The method utilized shown that after precipitation, washing and drying of precipitates at 150 0 C, the resulting solid was weighed in the form of [M{RCH(OH)COO} 4 ] (M = Zr,Hf;R = C 6 H 5 , β-C 10 H 7 ,p-BrC 6 H 4 ). (author) [pt

Determination of uranium by luminescent method (tablet variant)

International Nuclear Information System (INIS)

Sergeev, A.N.; Yufa, B.Ya.

1985-01-01

A new tablet variant of luminescent determination of uranium in rocks is developed. The analytical process includes the following operations: sample decomposition, uranium separation from luminescence quencher impurities, preparation of luminescent sample (tablet), photometry of the tablet. The method has two variants developed: the first one is characterized by a more hard decomposition, sample mass being 0.2 g; the second variant has a better detection limit (5x10 -6 %), the sample mass being 0.2-1 g. Procedures of the sample preparation for both variants of analysis are described

Gravimetric and volumetric approaches adapted for hydrogen sorption measurements with in situ conditioning on small sorbent samples

International Nuclear Information System (INIS)

Poirier, E.; Chahine, R.; Tessier, A.; Bose, T.K.

2005-01-01

We present high sensitivity (0 to 1 bar, 295 K) gravimetric and volumetric hydrogen sorption measurement systems adapted for in situ sample conditioning at high temperature and high vacuum. These systems are designed especially for experiments on sorbents available in small masses (mg) and requiring thorough degassing prior to sorption measurements. Uncertainty analysis from instrumental specifications and hydrogen absorption measurements on palladium are presented. The gravimetric and volumetric systems yield cross-checkable results within about 0.05 wt % on samples weighing from (3 to 25) mg. Hydrogen storage capacities of single-walled carbon nanotubes measured at 1 bar and 295 K with both systems are presented

Measuring intestinal fluid transport in vitro: Gravimetric method versus non-absorbable marker.

Science.gov (United States)

Whittamore, Jonathan M; Genz, Janet; Grosell, Martin; Wilson, Rod W

2016-04-01

The gut sac is a long-standing, widely used in vitro preparation for studying solute and water transport, and calculation of these fluxes requires an accurate assessment of volume. This is commonly determined gravimetrically by measuring the change in mass over time. While convenient this likely under-estimates actual net water flux (Jv) due to tissue edema. We evaluated whether the popular in vivo volume marker [(14)C]-PEG 4000, offers a more representative measure of Jvin vitro. We directly compared these two methods in five teleost species (toadfish, flounder, rainbow trout, killifish and tilapia). Net fluid absorption by the toadfish intestine based on PEG was significantly higher, by almost 4-fold, compared to gravimetric measurements, compatible with the latter under-estimating Jv. Despite this, PEG proved inconsistent for all of the other species frequently resulting in calculation of net secretion, in contrast to absorption seen gravimetrically. Such poor parallelism could not be explained by the absorption of [(14)C]-PEG (typically gravimetric method therefore remains the most reliable measure of Jv and we urge caution in the use of PEG as a volume marker. Copyright © 2016 Elsevier Inc. All rights reserved.

Near infrared spectrometry for faecal fat measurement: comparison with conventional gravimetric and titrimetric methods.

Science.gov (United States)

Benini, L; Caliari, S; Guidi, G C; Vaona, B; Talamini, G; Vantini, I; Scuro, L A

1989-01-01

This investigation was aimed at comparing a new method for measuring faecal fat excretion, carried out with a semi-automated instrument by using near infrared analysis (NIRA), with the traditional titrimetric (Van de Kamer) and gravimetric (Sobel) methods. Near infrared analysis faecal fat was assayed on the three day stool collection from 118 patients (68 chronic pancreatitis, 19 organic diseases of the gastrointestinal tract, 19 alcoholic liver disease, 12 functional gastrointestinal disorders). A strict linear correlation was found between NIRA and both the titrimetric (r = 0.928, p less than 0.0001) and the gravimetric (r = 0.971, p less than 0.0001) methods. On homogenised faeces, a mean coefficient of variation of 2.1 (SD 1.71)% was found. Before homogenisation (where a mean coefficient of variation of 7% was found) accurate results were obtained when the mean of five measurements was considered. In conclusion, the assay of faecal fat excretion by the near infrared reflessometry appears a simple, rapid and reliable method for measuring steatorrhoea. PMID:2583563

Methods of optical spectroscopy and luminescence in analysis of natural and waste waters

International Nuclear Information System (INIS)

Koryakin, A.V.; Gribovskaya, I.F.

1987-01-01

The actual problem of analytical control of the state of water contamination by heavy metals, biogenic substances, organic compounds, are considered. Methods for sampling, storage and preparation of samples for analysis, preparation of standard solutions are described. Some theoretical statements making it possible to improve certain techniques are given alongside with methods of atomic emission, atomic absorption and luminescence analysis of water (determination of microquantities of transition metals, lanthanides, actinides, etc). Methods for increase of sensitivity and reliability of the analysis, its rapidity are described

Analysis of the performance of interferometry, surface plasmon resonance and luminescence as biosensors and chemosensors

International Nuclear Information System (INIS)

Ince, R.; Narayanaswamy, R.

2006-01-01

Sensitivity, dynamic range and resolution have been calculated and compared from a range of analytes sensed in the literature using the techniques of interferometry, surface plasmon resonance (SPR) and luminescence. A detailed explanation of the physical and chemical/biological properties required of optical sensors is included along with the principle of operation of the sensors. Theoretical sensitivities of interferometry and SPR are also detailed along with parameters affecting these sensitivities. In the literature discussed in this review paper, the technique of luminescence, which relies intrinsically on 'labelling', offers the best resolutions for sensing of biomolecules (protein and DNA). Interference techniques offer the best resolutions for low molecular weight chemical liquids/vapours. Techniques which are 'label-free' are often desirable and it is demonstrated here that by combining the techniques of SPR with interferometry, it is possible to sense proteins with a resolution similar to that of luminescence. The future of chemo- and bio-sensing is discussed in terms of potential for multi-channel analysis, their continuous miniaturisation and their impending nanotechnology revolution

Microprobe analysis, iono- and photo-luminescence of Mn2+ activated ZnGa2O4 fibres

International Nuclear Information System (INIS)

Santos, N.F.; Fernandes, A.J.S.; Alves, L.C.; Sobolev, N.A.; Alves, E.; Lorenz, K.; Costa, F.M.; Monteiro, T.

2013-01-01

Cubic ZnGa 2 O 4 fibres have been grown by the laser floating zone technique with different pulling rates. In fibres activated with manganese ions, the room temperature photo- and iono-luminescence is dominated by an intense green emission which is observed by the naked eye. The green band is due to an overlap of the 4 T 1 → 6 A 1 intraionic transitions of the Mn 2+ ions in different sites in the gallate host. The fibres’ photoluminescence spectra have been found to be dependent on the excitation energy. Additionally, the intensity of the green photo- and iono-luminescence is strongly sensitive to the measurement temperature and proton irradiation time. Micro PIXE analysis was used in order to verify the homogeneous distribution of the Mn luminescence activators and determine its concentration as well as for verification of impurity contents that may have been incorporated during the fibres growth. The potential of ionoluminescence measurements for characterization of optical materials is discussed

40 CFR 1065.290 - PM gravimetric balance.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 32 2010-07-01 2010-07-01 false PM gravimetric balance. 1065.290... balance. (a) Application. Use a balance to weigh net PM on a sample medium for laboratory testing. (b) Component requirements. We recommend that you use a balance that meets the specifications in Table 1 of...

A gravimetric simplified method for nucleated marrow cell counting using an injection needle.

Science.gov (United States)

Saitoh, Toshiki; Fang, Liu; Matsumoto, Kiyoshi

2005-08-01

A simplified gravimetric marrow cell counting method for rats is proposed for a regular screening method. After fresh bone marrow was aspirated by an injection needle, the marrow cells were suspended in carbonate buffered saline. The nucleated marrow cell count (NMC) was measured by an automated multi-blood cell analyzer. When this gravimetric method was applied to rats, the NMC of the left and right femurs had essentially identical values due to careful handling. The NMC at 4 to 10 weeks of age in male and female Crj:CD(SD)IGS rats was 2.72 to 1.96 and 2.75 to 1.98 (x10(6) counts/mg), respectively. More useful information for evaluation could be obtained by using this gravimetric method in addition to myelogram examination. However, some difficulties with this method include low NMC due to blood contamination and variation of NMC due to handling. Therefore, the utility of this gravimetric method for screening will be clarified by the accumulation of the data on myelotoxicity studies with this method.

Computation of improved tidal parameters at the gravimetric station of Brasimone

Directory of Open Access Journals (Sweden)

P. Baldi

1997-06-01

Full Text Available Since 1991 a GWR superconducting gravimeter has been working in a laboratory at the Brasimone ENEA Research Centre, near Bologna (Italy, in the frame of an experimental program to verify Newton's law over distances of the order of 10-100 m. Owing to the aim of the experiment, the gravimeter was moved to different laboratories in the same area, but from August 1995 to date it has been working continuously in the same laboratory in the frame of the preliminary program of the Global Geodynamics Project. The site, belonging to a building of a dismissed nuclear power plant, is free from noise due to human activities, and is thus highly suitable for recording Earth tides. Starting from a set of gravimetric and atmospheric pressure data of high quality relative to 22 months of observation, we performed the tidal analysis using Eterna 3.2 software in order to compute amplitudes, gravimetric factors and phases of the main waves of the Tamura 1987 catalogue. The accuracy of the method adopted for the calibration of the gravimeter, the values of the principal waves and the result of the computation of atmospheric pressure admittance are described.

Luminescent beam stop

Energy Technology Data Exchange (ETDEWEB)

Bryant, Diane; Morton, Simon A.

2017-10-25

This disclosure provides systems, methods, and apparatus related to beam stops. In one aspect, a device comprises a luminescent material, a beam stop plate, and an optical fiber. The luminescent material is a parallelepiped having a first side and a second side that are squares and having a third side that is a rectangle or a square. The first side and the second side are perpendicular to the third side. The beam stop plate is attached to the first side of the luminescent material. The optical fiber has a first end and a second end, with the first end of the optical fiber attached to the third side of the luminescent material.

Interpretation of Gravimetric and Aeromagnetic Data of the Tecoripa Chart in Southeast Sonora, Mexico.

Science.gov (United States)

Martínez-Retama, S.; Montaño-Del Cid, M. A.

2015-12-01

The Tecoripa chart H12-D64 is located southeast of the state of Sonora, México, south of Arizona. The geology is represented by sedimentary rocks of the Ordovician and Triassic, volcanic rocks of the Upper Cretaceous and Tertiary, intrusive rocks from the Upper Cretaceous- Tertiary and sedimentary rocks of the Cenozoic. In this paper a gravimetric study was conducted to determine the configuration and depth of the basement and to develop a structural model of the subsurface. For this purpose a consistent gravimetric survey in 3 profiles was conducted. To complement this study, gravimetric data obtained by INEGI (96 gravimetric stations spaced every 4000 m) that correspond to a regional survey was also used. The two sets of data were corrected and processed with the WinGLink software. The profiles were then modeled using the Talwani method. 4 Profiles corresponding to the gravimetric survey and 5 data profiles from INEGI were modeled. Aeromagnetic data from the total field of Tecoripa chart were also processed. The digital information was integrated and processed by generating a data grid. Processes applied to data consisted of reduction to the pole, regional-residual separation and upward continuations. In general, the obtained structural models show intrusive bodies associated with well-defined high gravimetric and magnetic and low gravimetric and magnetic are associated with basins and sedimentary rocks. The obtained geological models show the basement represented by volcanic rocks of the Tarahumara Formation from the Upper Cretaceous which are in contact with sedimentary rocks from the Barranca Group from Upper Cretaceous and limestones from the Middle Ordovician. Both volcanic and sedimentary rocks are intruded by granodiorite- granite with ages of the Tertiary-Oligocene. Based on the superficial geology as well as in the configuration of the basement and the obtained structural model the existence of faults with NW-SE orientation that originate Horst and

Comparison of fine particle measurements from a direct-reading instrument and a gravimetric sampling method.

Science.gov (United States)

Kim, Jee Young; Magari, Shannon R; Herrick, Robert F; Smith, Thomas J; Christiani, David C

2004-11-01

Particulate air pollution, specifically the fine particle fraction (PM2.5), has been associated with increased cardiopulmonary morbidity and mortality in general population studies. Occupational exposure to fine particulate matter can exceed ambient levels by a large factor. Due to increased interest in the health effects of particulate matter, many particle sampling methods have been developed In this study, two such measurement methods were used simultaneously and compared. PM2.5 was sampled using a filter-based gravimetric sampling method and a direct-reading instrument, the TSI Inc. model 8520 DUSTTRAK aerosol monitor. Both sampling methods were used to determine the PM2.5 exposure in a group of boilermakers exposed to welding fumes and residual fuel oil ash. The geometric mean PM2.5 concentration was 0.30 mg/m3 (GSD 3.25) and 0.31 mg/m3 (GSD 2.90)from the DUSTTRAK and gravimetric method, respectively. The Spearman rank correlation coefficient for the gravimetric and DUSTTRAK PM2.5 concentrations was 0.68. Linear regression models indicated that log, DUSTTRAK PM2.5 concentrations significantly predicted loge gravimetric PM2.5 concentrations (p gravimetric PM2.5 concentrations was found to be modified by surrogate measures for seasonal variation and type of aerosol. PM2.5 measurements from the DUSTTRAK are well correlated and highly predictive of measurements from the gravimetric sampling method for the aerosols in these work environments. However, results from this study suggest that aerosol particle characteristics may affect the relationship between the gravimetric and DUSTTRAK PM2.5 measurements. Recalibration of the DUSTTRAK for the specific aerosol, as recommended by the manufacturer, may be necessary to produce valid measures of airborne particulate matter.

A study of luminescence and absorption spectra of GaP

International Nuclear Information System (INIS)

Mansour, H.M.M.; Abdel Wahab, S.M.

1994-08-01

Experimental luminescence and absorption spectra of GaP at room temperature are presented. A theoretical analysis has been performed on the luminescence and absorption spectra in GaP. The experimental data are in good agreement with the theoretical results. (author). 18 refs, 8 figs

Luminescent properties of terbium complexes with catecholamines and their application in analysis

International Nuclear Information System (INIS)

Kravchenko, T.B.; Bel'tyukova, S.V.; Kononenko, L.I.; Poluehktov, N.S.

1982-01-01

Tb complexing with a representative of catecholamines - adrenaline - is studied using the luminescence method. It is found, that the complexing takes place in alkaline medium (pH 12.0). To prevent from compound oxidation with air oxygen and to create the necessary pH in solution sodium borohydride is used. The highest luminescence intensity is achieved when the reaction occurs in aqueous-isopropanol solutions. It is established that in the complexes formed the ratio of components is the following: Tb:adrenaline=1:3. Luminescent properties of Tb complex with adrenaline are used to determine the latter. The least detectable amount of adrenaline constitutes 0.02 μg, the determination error does not exceed 5.5% [ru

Application of InSAR and gravimetric surveys for developing construction codes in zones of land subsidence induced by groundwater extraction: case study of Aguascalientes, Mexico

Directory of Open Access Journals (Sweden)

J. Pacheco-Martínez

2015-11-01

Full Text Available Interferometric Synthetic Aperture Radar (InSAR has become a valuable tool for surface deformation monitoring, including land subsidence associated with groundwater extraction. Another useful tools for studying Earth's surface processes are geophysical methods such as Gravimetry. In this work we present the application of InSAR analysis and gravimetric surveying to generate valuable information for risk management related to land subsidence and surface faulting. Subsidence of the city of Aguascalientes, Mexico is presented as study case. Aguascalientes local governments have addressed land subsidence issues by including new requirements for new constructions projects in the State Urban Construction Code. Nevertheless, the resulting zoning proposed in the code is still subjective and not clearly defined. Our work based on gravimetric and InSAR surveys is aimed for improving the subsidence hazard zoning proposed in the State Urban Code in a more comprehensive way. The study includes a 2007–2011 ALOS InSAR time-series analysis of the Aguascalientes valley, an interpretation of the compete Bouguer gravimetric anomaly of the Aguascalientes urban area, and the application of time series and gravimetric anomaly maps for improve the subsidence hazard zoning of Aguascalientes City.

Synthesis and luminescent properties of PEO/lanthanide oxide nanoparticle hybrid films

International Nuclear Information System (INIS)

Goubard, F.; Vidal, F.; Bazzi, R.; Tillement, O.; Chevrot, C.; Teyssie, D.

2007-01-01

In this study, we investigate the optical properties of lanthanide oxide nanoparticles dispersed in poly(ethylene oxide) (PEO) network as thermally stable polymeric films. The aim of this work is both to keep a good optical transparency in the visible domain and to obtain luminescent materials after incorporation of nanoparticles. For this purpose, we develop luminescent nanocrystals of oxides containing terbium ion as a doping element in Gd 2 O 3 . These sub-5-nm lanthanide oxides nanoparticles have been prepared by direct oxide precipitation in high-boiling polyalcohol solutions and characterized by luminescence spectroscopy. PEO/lanthanide oxide nanohybrid films are prepared by radical polymerization of poly(ethylene glycol) methacrylate after introduction of lanthanide oxide particles. As a first result; the obtained films present interesting luminescence properties with a very low lanthanide oxide content (up to 0.29 wt%). Furthermore, these films are still transparent and keep their original mechanical properties. Prior to describe the specific applications to optical use, we report here the dynamic mechanical analysis (DMA), X-ray diffraction (XRD) analysis, transmission electron microscopy (TEM), and luminescent properties of. nanohybrid films

Reduction Of Gravimetric Data Using An Integrated Computer ...

African Journals Online (AJOL)

The rigour of gravimetric data collection, and the non-availability of comprehensive data reduction software that takes care of local peculiarities, have always constituted hindrance to the application of the gravity method of geophysical studies. However, in recent time, the importance of the gravity method in mineral ...

Technical note: Comparison of metal-on-metal hip simulator wear measured by gravimetric, CMM and optical profiling methods

Science.gov (United States)

Alberts, L. Russell; Martinez-Nogues, Vanesa; Baker Cook, Richard; Maul, Christian; Bills, Paul; Racasan, R.; Stolz, Martin; Wood, Robert J. K.

2018-03-01

Simulation of wear in artificial joint implants is critical for evaluating implant designs and materials. Traditional protocols employ the gravimetric method to determine the loss of material by measuring the weight of the implant components before and after various test intervals and after the completed test. However, the gravimetric method cannot identify the location, area coverage or maximum depth of the wear and it has difficulties with proportionally small weight changes in relatively heavy implants. In this study, we compare the gravimetric method with two geometric surface methods; an optical light method (RedLux) and a coordinate measuring method (CMM). We tested ten Adept hips in a simulator for 2 million cycles (MC). Gravimetric and optical methods were performed at 0.33, 0.66, 1.00, 1.33 and 2 MC. CMM measurements were done before and after the test. A high correlation was found between the gravimetric and optical methods for both heads (R 2  =  0.997) and for cups (R 2  =  0.96). Both geometric methods (optical and CMM) measured more volume loss than the gravimetric method (for the heads, p  =  0.004 (optical) and p  =  0.08 (CMM); for the cups p  =  0.01 (optical) and p  =  0.003 (CMM)). Two cups recorded negative wear at 2 MC by the gravimetric method but none did by either the optical method or by CMM. The geometric methods were prone to confounding factors such as surface deformation and the gravimetric method could be confounded by protein absorption and backside wear. Both of the geometric methods were able to show the location, area covered and depth of the wear on the bearing surfaces, and track their changes during the test run; providing significant advantages to solely using the gravimetric method.

Characterization of the structure of the Salar de Atacama Basin through gravimetric profiles and interval velocity analysis.

Science.gov (United States)

Becerra, J.; Bascunan, S. A.; Maksymowicz, A.; Martínez, F.; Arriagada, C.

2017-12-01

The structure of the basins found in the Preandean Depression in the northern Central Andes has remained elusive, partly due to a poor understanding of the structural styles and stratigraphy beneath their surface. An independent approach to the multiple interpretations of seismic lines available is the analysis of 2D gravity profiles. An E-W profile was performed across the basin, closely matching the surficial trace of previous seismic lines. The profile shows three gravimetric lows, the most relevant being one beneath the Llano de la Paciencia- Cordillera de la Sal, comprised of deformed evaporitic and terrigenous deposits of Oligocene-Early Miocene age. The structure which bounds this gravity low has a steeper dip on its eastern side, bounding the eastern side of the Cordillera de la Sal, which is at odds with previous studies that interpreted its western contact with Cretaceous outcrops as the possible basin boundary. The 3-D analyses of seismic interval velocity data around the gravimetric survey reveal a major vertical contrast in the eastern portion of the profile, interpreted as the bottom of the evaporite successions, followed to the west by a complex, narrow and deep zone of low velocities. Westward, the Cretaceous rocks record higher velocities than its post-Paleocene counterparts, and an almost uniform increase in velocity with depth. The major gravity anomaly is closely related to the Cordillera de la Sal, which consists of an array of folds and reverse faults involving Oligocene to recent deposits. We propose that the faults which generated Oligocene extension are not at the western border of the basin, but around the Cordillera de la Sal, which is the result of Miocene inversion of the same system. Strike-slip deformation was also probably a major contributor in basin formation, as shown by the narrow yet deep shape of the depocenter.

Crumpled Nitrogen-Doped Graphene for Supercapacitors with High Gravimetric and Volumetric Performances.

Science.gov (United States)

Wang, Jie; Ding, Bing; Xu, Yunling; Shen, Laifa; Dou, Hui; Zhang, Xiaogang

2015-10-14

Graphene is considered a promising electrochemical capacitors electrode material due to its high surface area and high electrical conductivity. However, restacking interactions between graphene nanosheets significantly decrease the ion-accessible surface area and impede electronic and ionic transfer. This would, in turn, severely hinder the realization of high energy density. Herein, we report a strategy for preparation of few-layer graphene material with abundant crumples and high-level nitrogen doping. The two-dimensional graphene nanosheets (CNG) feature high ion-available surface area, excellent electronic and ion transfer properties, and high packing density, permitting the CNG electrode to exhibit excellent electrochemical performance. In ionic liquid electrolyte, the CNG electrode exhibits gravimetric and volumetric capacitances of 128 F g(-1) and 98 F cm(-3), respectively, achieving gravimetric and volumetric energy densities of 56 Wh kg(-1) and 43 Wh L(-1). The preparation strategy described here provides a new approach for developing a graphene-based supercapacitor with high gravimetric and volumetric energy densities.

Measurement of isotope abundance variations in nature by gravimetric spiking isotope dilution analysis (GS-IDA).

Science.gov (United States)

Chew, Gina; Walczyk, Thomas

2013-04-02

Subtle variations in the isotopic composition of elements carry unique information about physical and chemical processes in nature and are now exploited widely in diverse areas of research. Reliable measurement of natural isotope abundance variations is among the biggest challenges in inorganic mass spectrometry as they are highly sensitive to methodological bias. For decades, double spiking of the sample with a mix of two stable isotopes has been considered the reference technique for measuring such variations both by multicollector-inductively coupled plasma mass spectrometry (MC-ICPMS) and multicollector-thermal ionization mass spectrometry (MC-TIMS). However, this technique can only be applied to elements having at least four stable isotopes. Here we present a novel approach that requires measurement of three isotope signals only and which is more robust than the conventional double spiking technique. This became possible by gravimetric mixing of the sample with an isotopic spike in different proportions and by applying principles of isotope dilution for data analysis (GS-IDA). The potential and principle use of the technique is demonstrated for Mg in human urine using MC-TIMS for isotopic analysis. Mg is an element inaccessible to double spiking methods as it consists of three stable isotopes only and shows great potential for metabolically induced isotope effects waiting to be explored.

Terbium and dysprosium complexes luminescence at low temperatures

Energy Technology Data Exchange (ETDEWEB)

Meshkova, S B; Kravchenko, T B; Kononenko, L.I.; Poluehktov, N S [AN Ukrainskoj SSR, Odessa. Fiziko-Khimicheskij Inst.

1979-01-01

The variation is studied of the luminescence intensity of terbium and dysprosium complexes used in the analysis as solutions are cooled down to the liquid nitrogen temperature. Three groups of methods have been studied: observation of fluorescence of aqueous solutions, precipitate and extract suspensions in organic solvents. The brightest luminescence and greatest increase in luminescence intensity are observed at freezing of complex solvents with 1,2-dioxybenzene-3,5-disulfonic acid (DBSA) and iminodiacetic acid (IDA) and DBSA+EDTA, as well as in the case of benzene extracting of complexes with phenanthroline and salicylic acid. Otherwise the intensity increases 2-14-fold and for the complex of terbium with acetoacetic ester 36-fold.

Single photon detection and signal analysis for high sensitivity dosimetry based on optically stimulated luminescence with beryllium oxide

Science.gov (United States)

Radtke, J.; Sponner, J.; Jakobi, C.; Schneider, J.; Sommer, M.; Teichmann, T.; Ullrich, W.; Henniger, J.; Kormoll, T.

2018-01-01

Single photon detection applied to optically stimulated luminescence (OSL) dosimetry is a promising approach due to the low level of luminescence light and the known statistical behavior of single photon events. Time resolved detection allows to apply a variety of different and independent data analysis methods. Furthermore, using amplitude modulated stimulation impresses time- and frequency information into the OSL light and therefore allows for additional means of analysis. Considering the impressed frequency information, data analysis by using Fourier transform algorithms or other digital filters can be used for separating the OSL signal from unwanted light or events generated by other phenomena. This potentially lowers the detection limits of low dose measurements and might improve the reproducibility and stability of obtained data. In this work, an OSL system based on a single photon detector, a fast and accurate stimulation unit and an FPGA is presented. Different analysis algorithms which are applied to the single photon data are discussed.

Luminescence of water or ice as a new detection method for magnetic monopoles

Directory of Open Access Journals (Sweden)

Pollmann Anna Obertacke

2017-01-01

We present analysis techniques to use luminescence in neutrino telescopes and discuss experimental setups to measure the light yield of luminescence for the particular conditions in neutrino detectors.

Positron-Induced Luminescence

Science.gov (United States)

Stenson, E. V.; Hergenhahn, U.; Stoneking, M. R.; Pedersen, T. Sunn

2018-04-01

We report on the observation that low-energy positrons incident on a phosphor screen produce significantly more luminescence than electrons do. For two different wide-band-gap semiconductor phosphors (ZnS:Ag and ZnO:Zn), we compare the luminescent response to a positron beam with the response to an electron beam. For both phosphors, the positron response is significantly brighter than the electron response, by a factor that depends strongly on incident energy (0-5 keV). Positrons with just a few tens of electron-volts of energy (for ZnS:Ag) or less (for ZnO:Zn) produce as much luminescence as is produced by electrons with several kilo-electron-volts. We attribute this effect to valence band holes and excited electrons produced by positron annihilation and subsequent Auger processes. These results demonstrate a valuable approach for addressing long-standing questions about luminescent materials.

Simplified method for gravimetric determination of zirconium or hafnium with α-hydroxy carboxylic acids

International Nuclear Information System (INIS)

Barbieri, R.S.; Rocha, J.C.; Terra, V.R.; Marques Netto, A.

1989-01-01

The conditions for gravimetric determination of zirconium or hafnium by glicoloc acids derivatives were studied by thermogravimetric analysis. The method utilized shownd that after precipitation, washing and drying of precipitates at 150 o C, the resulting solid was weighed in the form of [M (RCH(OH)COO) 4 ] (M = Zr, Hf; R + C 6 H 5 , β-C 10 H 7 , p-BrC 6 H 4 ). (author)

Gravimetric and profilometric measurements of the ablation rates of photosensitive polymers at different wavelengths

International Nuclear Information System (INIS)

Dumont, Th.; Bischofberger, R.; Lippert, T.; Wokaun, A.

2005-01-01

The ablation rates of two polyimides (PMDA and DurimidTM) and one triazene polymer were studied by gravimetric (quartz microbalance) and profilometric (profilometer) methods at irradiation wavelengths of 193, 248 and 308 nm. The ablation rates determined by the two methods are discussed in the context of the absorption behavior of the materials. Furthermore, the consistence of the two experimental methods is discussed for the ablation rates of DurimidTM and the triazene polymer. The gravimetric measurements revealed a good correlation between the ablation rate and the absorption properties of the examined materials. The comparison of the gravimetric and the profilometric measurements suggest a significant mass removal, e.g. by formation of gaseous products, prior to the detection of changes in the surface morphology

Increasing lanthanide luminescence by use of the RETEL effect.

Science.gov (United States)

Leif, Robert C; Vallarino, Lidia M; Becker, Margie C; Yang, Sean

2006-08-01

Luminescent lanthanide complexes produce emissions with the narrowest-known width at half maximum; however, their significant use in cytometry required an increase in luminescence intensity. The companion review, Leif et al., Cytometry 2006;69A:767-778, described a new technique for the enhancement of lanthanide luminescence, the Resonance Energy Transfer Enhanced Luminescence (RETEL) effect, which increases luminescence and is compatible with standard slide microscopy. The luminescence of the europium ion macrocyclic complex, EuMac, was increased by employing the RETEL effect. After adding the nonluminescent gadolinium ion complex of the thenoyltrifluoroacetonate (TTFA) ligand or the sodium salt of TTFA in ethanol solution, the EuMac-labeled sample was allowed to dry. Both a conventional arc lamp and a time-gated UV LED served as light sources for microscopic imaging. The emission intensity was measured with a CCD camera. Multiple time-gated images were summed with special software to permit analysis and effective presentation of the final image. With the RETEL effect, the luminescence of the EuMac-streptavidin conjugate increased at least six-fold upon drying. Nuclei of apoptotic cells were stained with DAPI and tailed with 5BrdUrd to which a EuMac-anti-5BrdU conjugate was subsequently attached. Time-gated images showed the long-lived EuMac luminescence but did not show the short-lived DAPI fluorescence. Imaging of DNA-synthesizing cells with an arc lamp showed that both S phase and apoptotic cells were labeled, and that their labeling patterns were different. The images of the luminescent EuMac and fluorescent DAPI were combined to produce a color image on a white background. This combination of simple chemistry, instrumentation, and presentation should make possible the inexpensive use of the lanthanide macrocycles, Quantum Dyes, as molecular diagnostics for cytological and histopathological microscopic imaging. (c) 2006 International Society for Analytical

Luminescence from metals and insulators

International Nuclear Information System (INIS)

Crawford, O.H.

1985-01-01

The term luminescence is normally applied to light emission that is not explainable by the mechanisms discussed by the other speakers in this meeting. Specifically, it is not transition radiation, surface plasmon radiation, or bremsstrahlung. One normally thinks of luminescence as arising from one-electron transitions within a medium. This talk consists of an overview of luminescence from condensed matter under irradiation by either energetic particles or photons. The author begins with organic molecules, where luminescence is best understood, and then discusses inorganic insulators and metals. Finally, the dependence of yield upon projectile species and velocity is discussed, and predictions are made concerning the relative effectiveness of electrons, protons, and hydrogen atoms in exciting luminescence

A study on improvement of measurement capability for gravimetric flowmeter calibrator

International Nuclear Information System (INIS)

Lee, Dong Keun; Park, Jong Ho

2009-01-01

The calibration of flowmeter is a very important procedure to set up traceability from the national or international standards. The uncertainty of flow measurement defines reliability for measurement results. The uncertainty of gravimetric method combines uncertainties of each independent variable, including mass, time, water density, air density and the density of dead weight. In this study, it has been found that the uncertainties of mass and time measurement in the gravimetric method have dominant influence on the total measurement uncertainty. After improvements of a constant head tank and a diverter, the best measurement capability for K-water's calibration facility has been reached less than 0.1%.

Synthesis and luminescent properties of PEO/lanthanide oxide nanoparticle hybrid films

Energy Technology Data Exchange (ETDEWEB)

Goubard, F. [LPPI, Universite de Cergy-Pontoise, 5 Mail Gay-Lussac, Neuville-sur-Oise, 95031 Cergy-Pontoise cedex (France)]. E-mail: fabrice.goubard@u-cergy.fr; Vidal, F. [LPPI, Universite de Cergy-Pontoise, 5 Mail Gay-Lussac, Neuville-sur-Oise, 95031 Cergy-Pontoise cedex (France); Bazzi, R. [LPCML, Universite Lyon 1, 43 Bd. du 11 Novembre 1918, 69622 Villeurbanne (France); Tillement, O. [LPCML, Universite Lyon 1, 43 Bd. du 11 Novembre 1918, 69622 Villeurbanne (France); Nano-H, 23 rue Royal, 69001 Lyon (France); Chevrot, C. [LPPI, Universite de Cergy-Pontoise, 5 Mail Gay-Lussac, Neuville-sur-Oise, 95031 Cergy-Pontoise cedex (France); Teyssie, D. [LPPI, Universite de Cergy-Pontoise, 5 Mail Gay-Lussac, Neuville-sur-Oise, 95031 Cergy-Pontoise cedex (France)

2007-10-15

In this study, we investigate the optical properties of lanthanide oxide nanoparticles dispersed in poly(ethylene oxide) (PEO) network as thermally stable polymeric films. The aim of this work is both to keep a good optical transparency in the visible domain and to obtain luminescent materials after incorporation of nanoparticles. For this purpose, we develop luminescent nanocrystals of oxides containing terbium ion as a doping element in Gd{sub 2}O{sub 3}. These sub-5-nm lanthanide oxides nanoparticles have been prepared by direct oxide precipitation in high-boiling polyalcohol solutions and characterized by luminescence spectroscopy. PEO/lanthanide oxide nanohybrid films are prepared by radical polymerization of poly(ethylene glycol) methacrylate after introduction of lanthanide oxide particles. As a first result; the obtained films present interesting luminescence properties with a very low lanthanide oxide content (up to 0.29 wt%). Furthermore, these films are still transparent and keep their original mechanical properties. Prior to describe the specific applications to optical use, we report here the dynamic mechanical analysis (DMA), X-ray diffraction (XRD) analysis, transmission electron microscopy (TEM), and luminescent properties of. nanohybrid films.

The research of characteristic difference of selected frequency luminescence for desert sand

International Nuclear Information System (INIS)

Liu Chao; Wei Mingjian; Li Huhou

2011-01-01

The characters of selected frequency luminescence of four groups of samples from Badain Jaran desert are measured by BG2003 luminescence spectrograph. The measurement subjects include selected frequency optical stimulate luminescence spectrum, selected frequency thermoluminescence spectrum and the dose response curve. A double-peak map is obtained by the result from all groups of data and spectrum. The difference is emerged between each group. The optical stimulate luminescence and thermoluminescence is applied in the measurement process. The dispersion of photon count on every response wavelength is analyzed. Based on the analysis, a better result can be gained by selected frequency thermoluminescence. (authors)

Ion irradiation effect of alumina and its luminescence

Energy Technology Data Exchange (ETDEWEB)

Aoki, Yasushi; Yamamoto, Shunya; Naramoto, Hiroshi [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment; My, N T

1997-03-01

The luminescence spectra of single crystalline alpha-alumina and ruby which has 0.02% of Cr{sub 2}O{sub 3} as a impurity, induced by 200 keV He{sup +} and Ar{sup +} irradiation were measured at room temperature as a function of irradiation dose. The analysis of the measured spectra showed the existence of three main luminescence features in the wavelength region of 250 to 350 nm, namely anionic color centers, F-center at 411 nm and F{sup +}-center at 330 nm and a band observed around 315 nm. As alpha-alumina was irradiated with He{sup +}, F-center and F{sup +}-center luminescence grew and decayed, but the behaviors of those were different from each other. It seems that a concentration quenching occurred on the F-center luminescence in the dose range above 1x10{sup 14} He/cm{sup 2}. Furthermore, F-center luminescence was strongly suppressed in ruby, compared with that in alumina. On the other hand, the luminescence band around 315 nm appeared only in the early stage of irradiation and did not show its growth part. The dose dependent behavior was similar to that of Cr{sup 3+} emission at 695 nm (R-line) in ruby in both cases of He{sup +} and Ar{sup +} irradiation. Based on the experimental results mentioned above, the processes of defect formation and excitation in alumina in the early stage of ion irradiation will be discussed. (author)

Resonance-shifting luminescent solar concentrators

Energy Technology Data Exchange (ETDEWEB)

Giebink, Noel Christopher; Wiederrecht, Gary P.; Wasielewski, Michael R.

2018-01-23

An optical system and method to overcome luminescent solar concentrator inefficiencies by resonance-shifting, in which sharply directed emission from a bi-layer cavity into a glass substrate returns to interact with the cavity off-resonance at each subsequent reflection, significantly reducing reabsorption loss en route to the edges. In one embodiment, the system comprises a luminescent solar concentrator comprising a transparent substrate, a luminescent film having a variable thickness; and a low refractive index layer disposed between the transparent substrate and the luminescent film.

Feldspar, Infrared Stimulated Luminescence

DEFF Research Database (Denmark)

Jain, Mayank

2014-01-01

This entry primarily concerns the characteristics and the origins of infrared-stimulated luminescence in feldspars.......This entry primarily concerns the characteristics and the origins of infrared-stimulated luminescence in feldspars....

Comparison of gravimetric and spectrophotometric methods for the determination of O/U ratios in uranium oxides

International Nuclear Information System (INIS)

Esteban, Adolfo; Eppis, Maria Rosa

2004-01-01

One important parameter to specify in nuclear fuels is the oxygen-metal ratio; many tests were described in literature to determine it. Possibly, gravimetric methods are the most used and usually a good precision was obtained analysing sintered materials. However, the humidity sorbed in the samples and impurities affect these methods, especially in powders. On the other hand, the spectrophotometric methods determine oxygen-uranium ratio by measuring the absorbances of different ionic species in phosphoric acid. This technique is simply and is not affected by humidity and impurities. Owing to discrepancy in the results between both methods, it was carried out in our laboratory, a study on various gravimetric and spectrophotometric methods. Several assays and analysis were performed comparing test procedures, trying to obtain better precision and accuracy. This work presents the results obtained and the recommend procedure to use with sintered and unsintered materials

Time-resolved measurements of luminescence

Energy Technology Data Exchange (ETDEWEB)

Collier, Bradley B. [Department of Biomedical Engineering, 408 Mechanical Engineering Office Building, Spence Street, Texas A and M University, College Station, TX 77843 (United States); McShane, Michael J., E-mail: mcshane@tamu.edu [Department of Biomedical Engineering, 408 Mechanical Engineering Office Building, Spence Street, Texas A and M University, College Station, TX 77843 (United States); Materials Science and Engineering Program, 408 Mechanical Engineering Office Building, Spence Street, Texas A and M University, College Station, TX 77843 (United States)

2013-12-15

Luminescence sensing and imaging has become more widespread in recent years in a variety of industries including the biomedical and environmental fields. Measurements of luminescence lifetime hold inherent advantages over intensity-based response measurements, and advances in both technology and methods have enabled their use in a broader spectrum of applications including real-time medical diagnostics. This review will focus on recent advances in analytical methods, particularly calculation techniques, including time- and frequency-domain lifetime approaches as well as other time-resolved measurements of luminescence. -- Highlights: • Developments in technology have led to widespread use of luminescence lifetime. • Growing interest for sensing and imaging applications. • Recent advances in approaches to lifetime calculations are reviewed. • Advantages and disadvantages of various methods are weighed. • Other methods for measurement of luminescence lifetime also described.

Time-resolved measurements of luminescence

International Nuclear Information System (INIS)

Collier, Bradley B.; McShane, Michael J.

2013-01-01

Luminescence sensing and imaging has become more widespread in recent years in a variety of industries including the biomedical and environmental fields. Measurements of luminescence lifetime hold inherent advantages over intensity-based response measurements, and advances in both technology and methods have enabled their use in a broader spectrum of applications including real-time medical diagnostics. This review will focus on recent advances in analytical methods, particularly calculation techniques, including time- and frequency-domain lifetime approaches as well as other time-resolved measurements of luminescence. -- Highlights: • Developments in technology have led to widespread use of luminescence lifetime. • Growing interest for sensing and imaging applications. • Recent advances in approaches to lifetime calculations are reviewed. • Advantages and disadvantages of various methods are weighed. • Other methods for measurement of luminescence lifetime also described

Spectral luminescence and geochemistry of coral aragonite: Effects of whole-core treatment

NARCIS (Netherlands)

Nagtegaal, R.; Grove, C.A.; Kasper, S.; Zinke, J.; Brummer, G.J.A.

2012-01-01

Luminescent and geochemical properties of coral skeletons are increasingly used for time-series analysis to resolve past and ongoing changes in environmental and climatic conditions. Corals also contain non-skeletal matter which not only quenches luminescence but is also reported to compromise

Gravimetric determination of hafnium through its arsenate in carbide and boride of hafnium

International Nuclear Information System (INIS)

Rasulbekova, R.A.; Mamedov, I.A.

1976-01-01

A gravimetric method of determining hafnium through hydroarsenate has been recommended. The method differs from the known ones by its simplicity and by the recalculation coefficient which is more than by 50% smaller than that used in preparing a weight form of HfO 2 . Upon development of gravimetric determination of hafnium through hydro-and pyroarsenate, an investigation has been conducted with the aim to find some physico-chemical constants of hafnium hydroarsenate. The weighed amount of hafnium hydroarsenate is dissolved in sulphuric acid (2:5). The precipitate of hafnium hydroarsenate has been studied for recording infrared absorption spectra. Thermographic analysis of the precipitate has been performed. Thermogram reveals endothermal effect at 105 deg C and exothermal at 840 deg C. Water solubility of hafnium has been determined equal to 1.75x10 6 g mol/l. The corresponding solubility product of the precipitate has been calculated which is 2.1x10 -17 . It is shown that the method possesses certain selectivity, sufficient accuracy, and is rather fast. It has been established that determination can be performed in the presence of excess amounts of ions

Advantages and disadvantages of luminescence dosimetry

Energy Technology Data Exchange (ETDEWEB)

Olko, Pawel, E-mail: Pawel.Olko@ifj.edu.p [Institute of Nuclear Physics Polish Academy of Science (IFJ PAN), Krakow (Poland)

2010-03-15

Owing to their excellent dosimetric properties, luminescence detectors of ionizing radiation are now extensively applied in individual dosimetry services. The most frequently used personal dosemeters are based on Optically Stimulated Luminescence (OSL), radiophotoluminescence (RPL) or thermoluminescence (TL). Luminescence detectors have also found several applications in clinical dosimetry, especially around new radiation modalities in radiotherapy, such as Intensity Modulated Radiotherapy (IMRT) or ion beam radiotherapy. Requirements of luminescence detectors applied in individual and clinical dosimetry and some recent developments in luminescence of detectors and techniques leading to significant improvements of the functionality and accuracy of dosimetry systems are reviewed and discussed.

Linear least-squares method for global luminescent oil film skin friction field analysis

Science.gov (United States)

Lee, Taekjin; Nonomura, Taku; Asai, Keisuke; Liu, Tianshu

2018-06-01

A data analysis method based on the linear least-squares (LLS) method was developed for the extraction of high-resolution skin friction fields from global luminescent oil film (GLOF) visualization images of a surface in an aerodynamic flow. In this method, the oil film thickness distribution and its spatiotemporal development are measured by detecting the luminescence intensity of the thin oil film. From the resulting set of GLOF images, the thin oil film equation is solved to obtain an ensemble-averaged (steady) skin friction field as an inverse problem. In this paper, the formulation of a discrete linear system of equations for the LLS method is described, and an error analysis is given to identify the main error sources and the relevant parameters. Simulations were conducted to evaluate the accuracy of the LLS method and the effects of the image patterns, image noise, and sample numbers on the results in comparison with the previous snapshot-solution-averaging (SSA) method. An experimental case is shown to enable the comparison of the results obtained using conventional oil flow visualization and those obtained using both the LLS and SSA methods. The overall results show that the LLS method is more reliable than the SSA method and the LLS method can yield a more detailed skin friction topology in an objective way.

Gravimetric analysis and differential scanning calorimetric studies on glycerin-induced skin hydration.

Science.gov (United States)

Lee, Ae-Ri Cho; Moon, Hee Kyung

2007-11-01

A thermal gravimetric analysis (TGA) and a differential scanning calorimetry (DSC) were carried out to characterize the water property and an alteration of lipid phase transition of stratum corneum (SC) by glycerin. In addition, the relationship between steady state skin permeation rate and skin hydration in various concentrations of glycerin was investigated. Water vapor absorption-desorption was studied in the hairless mouse stratum corneum. Dry SC samples were exposed to different conc. of glycerin (0-50%) followed by exposure to dry air and the change in weight property was monitored over time by use of TGA. In DSC study, significant decrease in DeltaH of the lipid transition in 10% glycerin and water treated sample: the heat of lipid transition of normal, water, 10% glycerin treated SC were 6.058, 4.412 and 4.316 mJ/mg, respectively. In 10% glycerin treated SCs, the Tc of water shifts around 129 degrees C, corresponding to the weakly bound secondary water. In 40% glycerin treated SC, the Tc of water shifts to 144 degrees C corresponding to strongly bound primary water. There was a good correlation between the hydration property of the skin and the steady state skin flux with the correlation coefficient (r2=0.94). As the hydration increased, the steady state flux increased. As glycerin concentration increased, hydration property decreased. High diffusivity induced by the hydration effect of glycerin and water could be the major contributing factor for the enhanced skin permeation of nicotinic acid (NA).

Analysis of the luminescent spectra of Eu{sup 3+} in glasses

Energy Technology Data Exchange (ETDEWEB)

Jiang, Sha; Wei, Xiantao; Chen, Zhejia; Chen, Yonghu, E-mail: yhuchen@ustc.edu.cn; Yin, Min

2013-11-15

The spectroscopy properties of lanthanide ions in glasses differ remarkably from crystal and powder samples due to superposition of transitions from many ions with different local environments. Eu{sup 3+} ions were doped in lead–borosilicate and boro–tellurite glass samples to probe the structural information and to reveal their effects on the luminescent properties of lanthanide ions. Three emission peaks were observed for {sup 5}D{sub 0}→{sup 7}F{sub 0} transition, with peak energies linearly dependent on the excitation wavelengths, and correlation between the intensity ratio of {sup 5}D{sub 0}→{sup 7}F{sub 0} versus {sup 5}D{sub 0}→{sup 7}F{sub 2} and the width of {sup 7}F{sub 1} was observed. The former indicates that there are three subsets of Eu{sup 3+} sites in the samples, with {sup 7}F{sub 0} being pushed downwards by {sup 7}F{sub J} (J=2, 4, and 6) by crystal-field J-mixing, and the latter can be quantitatively modeled by the adaptation of the theoretical model of Wen et al. [Phys. Chem. Chem. Phys. 12, 9933 (2010)] to account for the corrections due to the inhomogeneous broadening of {sup 7}F{sub J} (J=0, and1) crystal-field levels. The methods explored here can be applied to study other glass hosts for luminescent materials. -- Highlights: • The quantitative analysis of Eu{sup 3+5}D{sub 0}→{sup 7}F{sub 0} emission spectra in glasses. • Improved data fitting with the modified CF splitting width calculation method. • Demonstration of the generality of the spectral analysis method in two glasses.

Study on the relationship of protease production and luminescence in Vibrio harveyi.

Science.gov (United States)

Nakayama, T; Nomura, N; Matsumura, M

2006-07-01

To demonstrate that Vibrio harveyi produces various types of toxins and how the production of those toxins is related with luminescence. Luminescence and toxicity of eight V. harveyi were evaluated. We demonstrated that all V. harveyi emitting luminescence were isolated from marine organisms and also showed that they were highly pathogenic when compared with culture collection V. harveyi based on cytotoxic assay test. On the contrary, V. harveyi isolated from shrimp farm showed no luminescence but showed high pathogenicity based on toxicity test. The effect of protease inhibitors on pathogenicity and luminescence was also investigated. We demonstrated that light emission of pathogenic V. harveyi remarkably decreased after addition of protease inhibitor. Furthermore, extracellular proteins from cell-free culture supernatant of luminescent and nonluminescent V. harveyi were compared using SDS-PAGE analysis. Results showed that there were differences in molecular weight and amount of proteins. Vibrio harveyi parasiting marine organisms have both luminescence and pathogenicity. Based on this study, luminescence and protease toxin activity in V. harveyi are related. Moreover, this paper clarified that V. harveyi produces various types of toxins. The current study demonstrated that V. harveyi produces two kinds of toxins, haemolysin and protease toxin. It may be clear roots of V. harveyi toxin.

Exciton luminescence in CdxMn1-xTe compounds

International Nuclear Information System (INIS)

Caraman, M.; Gashin, P.; Metelitsa, Snejana; Nicorici, Valentina; Nicorici, A.

2002-01-01

The Cd x Mn 1-x Te (0.5 7 W/cm 2 . The luminescence spectra were observed at 78 K. The results of the study had shown that the presence of relatively narrow luminescence peaks localized in the region of the fundamental absorption edge is characteristic for these spectra and for the majority of the crystals a wide maximum in the long wavelength region is observed. The luminescence maxima with an accuracy of ∼ 5 meV correspond to the resonance energy of the excitons of the state with n=1 determined from the absorption spectra. Hence, these maxima can be considered as exciton luminescence stimulated either by the excitons of the state n=1 or bounded to the exciton ionization centers. From the analysis of the absorption and exciton luminescence spectra one can make a conclusion about the fact that the homogeneity extent of the crystals decreases from CdTe to the compounds with x= 0.8 - 0.7 and slightly increases at the x decrease to 0.5. The exciton luminescence lines in CdTe and Cd 0.99 Mn 0.01 Te crystals is shifting by 7 - 10 meV relatively to the lines of free excitons absorption. This fact is explained by the fact that in these crystals, probably, excitons bounding to the lattice inherited defects with the binding energy of 7 - 10 meV participate in the luminescence. In the long wavelength region a wide peak is observed on which the impurity lines are not displayed. In the luminescence spectra of CdTe with 0.1%. As crystals three maxima at 1.51 eV, 1.46 eV and 1.42 eV are revealed. For pure CdTe the maximum at 1.4 eV is also revealed. These maxima are explained by the luminescence through the recombination levels localized at 0.46 eV. (authors)

Spectrophotometric, potentiometric, and gravimetric determination of lanthanides with peri-dihydroxynaphthindenone

International Nuclear Information System (INIS)

Hassan, S.S.M.; Mahmoud, W.H.

1982-01-01

Sensitive and reasonably selective methods are described for the spectrophotometric, potentiometric, and gravimetric determination of lanthanides using peri-dihydroxynaphthindenone as a novel chromogenic and precipitating reagent. The reagent forms a stable 1:2 (metal:reagent) type of complex with light lanthanides at pH 2-7 in 1:1 ethanol-water mixture. Low metal concentrations ( 4 L mol -1 cm -1 ) which obey Beer's law. Quantitative precipitation of the complexes from metal solutions of concentrations > 100 μg/mL permits both gravimetric quantitation by igniting the precipitates to the metal oxides and potentiometric titration of the excess reagent. Results with an average recovery of 98% (standard deviation 0.7%) are obtainable for 0.1 μg to 200 mg of all light lanthanides. Many foreign ions naturally occurring or frequently associated with lanthanides do not interfere or can be tolerated

Ion beam induced luminescence from diamond using an MeV ion microprobe

Energy Technology Data Exchange (ETDEWEB)

Bettiol, A.A.; Jamieson, D. N.; Prawer, S.; Allen, M.G. [Melbourne Univ., Parkville, VIC (Australia). School of Physics

1993-12-31

Analysis of the luminescence induced by a MeV ion beam offers the potential to provide useful information about the chemical properties of atoms in crystals to complement the information provided by more traditional Ion Beam Analysis (IBA) such as Rutherford Backscattering Spectrometry (RBS), ion channeling and Particle Induced X-ray Emission (PIXE). Furthermore, the large penetration depth of the MeV ion beam offers several advantages over the relatively shallow penetration of keV electrons typically employed in cathodoluminescence. An Ion Beam Induced Luminescence (IBIL) detection system was developed for the Melbourne microprobe that allows the spatial mapping of the luminescence signal along with the signals from RBS and PIXE. Homoepitaxial diamond growth has been studied and remarkable shifts in the characteristic blue luminescence of diamond towards the green were observed in the overgrowth. This has been tentatively identified as being due to transition metal inclusions in the epitaxial layers. 8 refs., 2 refs.

Ion beam induced luminescence from diamond using an MeV ion microprobe

Energy Technology Data Exchange (ETDEWEB)

Bettiol, A A; Jamieson, D N; Prawer, S; Allen, M G [Melbourne Univ., Parkville, VIC (Australia). School of Physics

1994-12-31

Analysis of the luminescence induced by a MeV ion beam offers the potential to provide useful information about the chemical properties of atoms in crystals to complement the information provided by more traditional Ion Beam Analysis (IBA) such as Rutherford Backscattering Spectrometry (RBS), ion channeling and Particle Induced X-ray Emission (PIXE). Furthermore, the large penetration depth of the MeV ion beam offers several advantages over the relatively shallow penetration of keV electrons typically employed in cathodoluminescence. An Ion Beam Induced Luminescence (IBIL) detection system was developed for the Melbourne microprobe that allows the spatial mapping of the luminescence signal along with the signals from RBS and PIXE. Homoepitaxial diamond growth has been studied and remarkable shifts in the characteristic blue luminescence of diamond towards the green were observed in the overgrowth. This has been tentatively identified as being due to transition metal inclusions in the epitaxial layers. 8 refs., 2 refs.

Principal and secondary luminescence lifetime components in annealed natural quartz

International Nuclear Information System (INIS)

Chithambo, M.L.; Ogundare, F.O.; Feathers, J.

2008-01-01

Time-resolved luminescence spectra from quartz can be separated into components with distinct principal and secondary lifetimes depending on certain combinations of annealing and measurement temperature. The influence of annealing on properties of the lifetimes related to irradiation dose and temperature of measurement has been investigated in sedimentary quartz annealed at various temperatures up to 900 deg. C. Time-resolved luminescence for use in the analysis was pulse stimulated from samples at 470 nm between 20 and 200 deg. C. Luminescence lifetimes decrease with measurement temperature due to increasing thermal effect on the associated luminescence with an activation energy of thermal quenching equal to 0.68±0.01eV for the secondary lifetime but only qualitatively so for the principal lifetime component. Concerning the influence of annealing temperature, luminescence lifetimes measured at 20 deg. C are constant at about 33μs for annealing temperatures up to 600 0 C but decrease to about 29μs when the annealing temperature is increased to 900 deg. C. In addition, it was found that lifetime components in samples annealed at 800 deg. C are independent of radiation dose in the range 85-1340 Gy investigated. The dependence of lifetimes on both the annealing temperature and magnitude of radiation dose is described as being due to the increasing importance of a particular recombination centre in the luminescence emission process as a result of dynamic hole transfer between non-radiative and radiative luminescence centres

Accuracy criteria recommended for the certification of gravimetric coal-mine-dust samplers

International Nuclear Information System (INIS)

Bowman, J.D.; Bartley, D.L.; Breuer, G.M.; Doemeny, L.J.; Murdock, D.J.

1984-07-01

Procedures for testing bias and precision of gravimetric coal-mine-dust sampling units are reviewed. Performance criteria for NIOSH certification of personal coal-mine dust samplers are considered. The NIOSH criterion is an accuracy of 25% at the 95% confidence interval. Size distributions of coal-mine-dust are discussed. Methods for determining size distributions are described. Sampling and sizing methods are considered. Cyclone parameter estimation is discussed. Bias computations for general sampling units are noted. Recommended procedures for evaluating bias and precision of gravimetric coal mine dust personal samplers are given. The authors conclude that when cyclones are operated at lower rates, the NIOSH accuracy criteria can be met

Silica-modified luminescent LaPO4 :Eu@LaPO4 @SiO2 core/shell nanorods: Synthesis, structural and luminescent properties.

Science.gov (United States)

Ansari, Anees A

2018-02-01

Monoclinic-type tetragonal LaPO 4 :Eu (core) and LaPO 4 :Eu@LaPO 4 (core/shell) nanorods (NRs) were successfully prepared using a urea-based co-precipitation process under ambient conditions. An amorphous silica layer was coated around the luminescent core/shell NRs via the sol-gel process to improve their solubility and colloidal stability in aqueous and non-aqueous media. The prepared nano-products were systematically characterized by X-ray diffraction pattern, transmission electron microscopy, energy dispersive X-ray analysis, and FTIR, UV/Vis, and photoluminescence spectroscopy to examine their phase purity, crystal phase, surface chemistry, solubility and luminescence characteristics. The length and diameter of the nano-products were in the range 80-120 nm and 10-15 nm, respectively. High solubility of the silica-modified core/shell/Si NRs was found for the aqueous medium. The luminescent core NRs exhibited characteristic excitation and emission transitions in the visible region that were greatly affected by surface growth of insulating LaPO 4 and silica layers due to the multiphonon relaxation rate. Our luminescence spectral results clearly show a distinct difference in intensities for core, core/shell, and core/shell/Si NRs. Highly luminescent NRs with good solubility could be useful candidates for a variety of photonic-based biomedical applications. Copyright © 2017 John Wiley & Sons, Ltd.

Paper-based biodetection using luminescent nanoparticles.

Science.gov (United States)

Ju, Qiang; Noor, M Omair; Krull, Ulrich J

2016-05-10

Point-of-care and in-field technologies for rapid, sensitive and selective detection of molecular biomarkers have attracted much interest. Rugged bioassay technology capable of fast detection of markers for pathogens and genetic diseases would in particular impact the quality of health care in the developing world, but would also make possible more extensive screening in developed countries to tackle problems such as those associated with water and food quality, and tracking of infectious organisms in hospitals and clinics. Literature trends indicate an increasing interest in the use of nanomaterials, and in particular luminescent nanoparticles, for assay development. These materials may offer attributes for development of assays and sensors that could achieve improvements in analytical figures of merit, and provide practical advantages in sensitivity and stability. There is opportunity for cost-efficiency and technical simplicity by implementation of luminescent nanomaterials as the basis for transduction technology, when combined with the use of paper substrates, and the ubiquitous availability of cell phone cameras and associated infrastructure for optical detection and transmission of results. Luminescent nanoparticles have been described for a broad range of bioanalytical targets including small molecules, oligonucleotides, peptides, proteins, saccharides and whole cells (e.g., cancer diagnostics). The luminescent nanomaterials that are described herein for paper-based bioassays include metal nanoparticles, quantum dots and lanthanide-doped nanocrystals. These nanomaterials often have broad and strong absorption and narrow emission bands that improve opportunity for multiplexed analysis, and can be designed to provide emission at wavelengths that are efficiently processed by conventional digital cameras. Luminescent nanoparticles can be embedded in paper substrates that are designed to direct fluid flow, and the resulting combination of technologies can offer

Gravimetric dust sampling for control purposes and occupational dust sampling.

CSIR Research Space (South Africa)

Unsted, AD

1997-02-01

Full Text Available Prior to the introduction of gravimetric dust sampling, konimeters had been used for dust sampling, which was largely for control purposes. Whether or not absolute results were achievable was not an issue since relative results were used to evaluate...

Method for the Collection, Gravimetric and Chemical Analysis of Nonvolatile Residue (NVR) on Surfaces

Science.gov (United States)

Gordon, Keith; Rutherford, Gugu; Aranda, Denisse

2017-01-01

Nonvolatile residue (NVR), sometimes referred to as molecular contamination is the term used for the total composition of the inorganic and high boiling point organic components in particulates and molecular films deposited on critical surfaces surrounding space structures, with the particulate and NVR contamination originating primarily from pre-launch operations. The "nonvolatile" suggestion from the terminology NVR implies that the collected residue will not experience much loss under ambient conditions. NVR has been shown to have a dramatic impact on the ability to perform optical measurements from platforms based in space. Such contaminants can be detected early by the controlled application of various detection techniques and contamination analyses. Contamination analyses are the techniques used to determine if materials, components, and subsystems can be expected to meet the performance requirements of a system. Of particular concern is the quantity of NVR contaminants that might be deposited on critical payload surfaces from these sources. Subsequent chemical analysis of the contaminant samples by infrared spectroscopy and gas chromatography mass spectrometry identifies the components, gives semi-quantitative estimates of contaminant thickness, indicates possible sources of the NVR, and provides guidance for effective cleanup procedures. In this report, a method for the collection and determination of the mass of NVR was generated by the authors at NASA Langley Research Center. This report describes the method developed and implemented for collecting NVR contaminants, and procedures for gravimetric and chemical analysis of the residue obtained. The result of this NVR analysis collaboration will help pave the way for Langley's ability to certify flight hardware outgassing requirements in support of flight projects such as Stratospheric Aerosol and Gas Experiment III (SAGE III), Clouds and the Earth's Radiant Energy System (CERES), Materials International

Comparison of gravimetric and gas chromatographic methods for assessing performance of textile materials against liquid pesticide penetration.

Science.gov (United States)

Shaw, Anugrah; Abbi, Ruchika

2004-01-01

Penetration of liquid pesticides through textile materials is a criterion for determining the performance of protective clothing used by pesticide handlers. The pipette method is frequently used to apply liquid pesticides onto textile materials to measure penetration. Typically, analytical techniques such as Gas Chromatography (GC) are used to measure percentage penetration. These techniques are labor intensive and costly. A simpler gravimetric method was developed, and tests were conducted to compare the gravimetric and GC methods of analysis. Three types of pesticide formulations and 4 fabrics were used for the study. Diluted pesticide formulations were pipetted onto the test specimens and percentage penetration was measured using the 2 methods. For homogeneous formulation, the results of the two methods were fairly comparable. However, due to the filtering action of the textile materials, there were differences in the percentage penetration between the 2 methods for formulations that were not homogeneous.

Seismic Moment and Recurrence using Luminescence Dating Techniques: Characterizing brittle fault zone materials suitable for luminescence dating

Science.gov (United States)

Tsakalos, E.; Lin, A.; Bassiakos, Y.; Kazantzaki, M.; Filippaki, E.

2017-12-01

During a seismic-geodynamic process, frictional heating and pressure are generated on sediments fragments resulting in deformation and alteration of minerals contained in them. The luminescence signal enclosed in minerals crystal lattice can be affected and even zeroed during such an event. This has been breakthrough in geochronological studies as it could be utilized as a chronometer for the previous seismic activity of a tectonically active area. Although the employment of luminescence dating has in some cases been successfully described, a comprehensive study outlining and defining protocols for routine luminescence dating applied to neotectonic studies has not been forthcoming. This study is the experimental investigation, recording and parameterization of the effects of tectonic phenomena on minerals luminescence signal and the development of detailed protocols for the standardization of the luminescence methodology for directly dating deformed geological formations, so that the long-term temporal behaviour of seismically active faults could be reasonably understood and modeled. This will be achieved by: a) identifying and proposing brittle fault zone materials suitable for luminescence dating using petrological, mineralogical and chemical analyses and b) investigating the "zeroing" potential of the luminescence signal of minerals contained in fault zone materials by employing experimental simulations of tectonic processes in the laboratory, combined with luminescence measurements on samples collected from real fault zones. For this to be achieved, a number of samples collected from four faults of four different geographical regions will be used. This preliminary-first step of the study presents the microstructural, and mineralogical analyses for the characterization of brittle fault zone materials that contain suitable minerals for luminescence dating (e.g., quartz and feldspar). The results showed that the collected samples are seismically deformed fault

Atomic-scale luminescence measurement and theoretical analysis unveiling electron energy dissipation at a p-type GaAs(110) surface

International Nuclear Information System (INIS)

Imada, Hiroshi; Miwa, Kuniyuki; Jung, Jaehoon; Shimizu, Tomoko K; Kim, Yousoo; Yamamoto, Naoki

2015-01-01

Luminescence of p-type GaAs was induced by electron injection from the tip of a scanning tunnelling microscope into a GaAs(110) surface. Atomically-resolved photon maps revealed a significant reduction in luminescence intensity at surface electronic states localized near Ga atoms. Theoretical analysis based on first principles calculations and a rate equation approach was performed to describe the perspective of electron energy dissipation at the surface. Our study reveals that non-radiative recombination through the surface states (SS) is a dominant process for the electron energy dissipation at the surface, which is suggestive of the fast scattering of injected electrons into the SS. (paper)

Novel lanthanide doped micro- and mesoporous solids. Characterization of ion-host-interactions, species distribution and luminescence properties using time-resolved luminescence spectroscopy

International Nuclear Information System (INIS)

Gessner, Andre

2010-12-01

In this work lanthanide-doped microporous zeolites, microporous-mesoporous hybrid materials and mesoporous silicates were investigated regarding their luminescence properties and the ion-host-interactions using time-resolved luminescence spectroscopy. Thereby, time-resolved emission spectra (TRES) provide information in the wavelength and time domain. For the analysis of the TRES a broad set of analytic methods was applied and thus a corresponding ''toolbox'' developed. Fitting of the luminescence decays was performed with a discrete number of exponentials and supported by luminescence decay times distributions. Time-resolved area normalized emission spectra (TRANES), an advancement of TRES, could be used for the determination of the number of emissive lanthanide species in porous materials for the first time. Calculation of the decay-associated spectra (DAS) allowed the correlation of spectral information with luminescence decay times and thus delivered the luminescence spectra of the different europium species. For europium(III) we could use in addition the time-dependent asymmetry ratio and spectral evolution of the 5 D 0 - 7 F 0 -transition with time to obtain further information about the distribution of the lanthanide ions in the host material. Luminescence decay times and spectra allowed conclusions on the number of OH-oscillators in and the symmetry of the first coordination sphere. For the microporous and microporous-mesoporous materials were found different lanthanide species, which were characterized by the above mentioned methods. These lanthanide species can be found on different positions in the host material. One position is located deep in the pore system. Here, lanthanide ions are hardly accessible for water and mainly coordinated by framework oxygens. This results in long luminescence decay times and distorted coordination spheres. The second position can be found near or on the outer surface or in the mesopores. Lanthanide ions located here, are

Gravimetric determination of the iodine number of carbon black

International Nuclear Information System (INIS)

Murphy, L.J. Jr.

1991-01-01

This paper discusses a gravimetric method for the determination of the iodine adsorption number of carbon black. It comprises determining the concentration of an accurately weighed iodine blank solution by adding a standardized titrant to the iodine solution until a titration endpoint is reached and determining the concentration of the iodine solution by accurately weighing the amount of the standardized titrant necessary to reach the endpoint, accurately weighing an amount of carbon black and adding an appropriate amount of an accurately weighed portion of the iodine solution, equilibrating the carbon black-iodine solution mixture, adding the standardized titrant to an accurately weighed portion of the supernatant from the carbon black-iodine mixture until a titration endpoint is reached and determining the concentration of the supernatant by accurately weighing the amount of the standardized titrant necessary to reach the endpoint, wherein the titration endpoint of the supernatant is obtained using an indicating and a reference electrode, and calculating the iodine adsorption number of the carbon black based on the gravimetrically determined concentration of the titrant, the iodine solution, and the supernatant

Quantitative luminescence imaging system

Science.gov (United States)

Erwin, David N.; Kiel, Johnathan L.; Batishko, Charles R.; Stahl, Kurt A.

1990-01-01

The QLIS images and quantifies low-level chemiluminescent reactions in an electromagnetic field. It is capable of real time nonperturbing measurement and simultaneous recording of many biochemical and chemical reactions such as luminescent immunoassays or enzyme assays. The system comprises image transfer optics, a low-light level digitizing camera with image intensifying microchannel plates, an image process or, and a control computer. The image transfer optics may be a fiber image guide with a bend, or a microscope, to take the light outside of the RF field. Output of the camera is transformed into a localized rate of cumulative digitalized data or enhanced video display or hard-copy images. The system may be used as a luminescent microdosimetry device for radiofrequency or microwave radiation, as a thermal dosimeter, or in the dosimetry of ultra-sound (sonoluminescence) or ionizing radiation. It provides a near-real-time system capable of measuring the extremely low light levels from luminescent reactions in electromagnetic fields in the areas of chemiluminescence assays and thermal microdosimetry, and is capable of near-real-time imaging of the sample to allow spatial distribution analysis of the reaction. It can be used to instrument three distinctly different irradiation configurations, comprising (1) RF waveguide irradiation of a small Petri-dish-shaped sample cell, (2) RF irradiation of samples in a microscope for the microscopie imaging and measurement, and (3) RF irradiation of small to human body-sized samples in an anechoic chamber.

Metal plasmon enhanced europium complex luminescence

International Nuclear Information System (INIS)

Liu Feng; Aldea, Gabriela; Nunzi, Jean-Michel

2010-01-01

The plasmon enhanced luminescence of a rare-earth complex Tris(6, 6, 7, 7, 8, 8, 8-heptafluoro-2, 2-dimethyl-3, 5-octanedionato) europium (Eu(fod) 3 ) was investigated. A polyvinyl alcohol (PVA) thin film was successfully adopted as a spacer to separate the Eu complex from the silver island film (SIF), and five-fold enhancement of the radiative decay rate of the Eu complex on SIF was demonstrated based on the luminescence intensity and lifetime measurement. Investigation of the distance dependent luminescence indicates that 7 nm is an optimal distance for SIF enhanced Eu luminescence. Plasmon enhanced rare-earth luminescence based on an organic film spacer would find potential applications in plasmon enhanced organic light emitting diode (OLED) devices.

Conversion efficiency of implanted ions by confocal micro-luminescence mapping

International Nuclear Information System (INIS)

Deshko, Y.; Huang, Mengbing; Gorokhovsky, A.A.

2013-01-01

We report on the further development of the statistical approach to determine the conversion efficiency of implanted ions into emitting centers and present the measurement method based on the confocal micro-luminescence mapping. It involves the micro-luminescence mapping with a narrow-open confocal aperture, followed by the statistical analysis of the photoluminescence signal from an ensemble of emitting centers. The confocal mapping method has two important advantages compared to the recently discussed aperture-free method (J. Lumin. 131 (2011) 489): it is less sensitive to errors in the laser spot size and has a well defined useful area. The confocal mapping has been applied to the Xe center in diamond. The conversion efficiency has been found to be about 0.28, which is in good agreement with the results of the aperture-free method. - Highlights: ► Conversion efficiency of implanted ions into emitting centers – statistical approach. ► Micro-luminescence mapping with open and narrow confocal aperture – comparison. ► Advantages of the confocal micro-luminescence mapping. ► Confocal micro-luminescence mapping has been applied to the Xe center in diamond. ► The conversion efficiency has been found to be about 0.28.

Determination of uranium in uranyl nitrate solutions of nuclear grade quality - Gravimetric method

International Nuclear Information System (INIS)

1990-01-01

This international Standard specifies a precise and accurate gravimetric method for determining the uranium content in uranyl nitrate product solutions of nuclear grade quality at concentrations above 100 g/l of uranium. Non-volatile impurities influence the accuracy of the method. Uranyl nitrate is converted into uranium octoxide (U 3 O 8 ) by ignition in air to constant mass at 900 deg. C ± 10 deg. C. Calculation of the uranium content in the sample using a gravimetric conversion factor which depends on the isotopic composition of the uranium. The isotopic composition is determined by mass spectrometry

Gravimetric study on the western edge of the Rio de La Plata craton

International Nuclear Information System (INIS)

Rame, G; Miro, R

2010-01-01

This work is about the gravimetric study on the western edge of the Rio de la Plata craton which belongs to the Gondwana fragment in the south of Brazil, Uruguay and central eastern of Argentina. The work consisted of a survey of 332 gravimetric and topographic stations extended from the western edge of the Sierra Chica de Cordoba up to 200 km east on the pampas. The gravity values observed (gobs) were obtained using a LaCoste §Rom berg gravimeter G-961 and 200T Sodin both with 0.01 mGal, referred to IGSN71 (International Gravity Standardization Net 1971) network

A gravimetric and an X-ray fluorescence method for the determination of rubidium in Rb2U(SO4)3

International Nuclear Information System (INIS)

Mudher, K.D.S.; Krishnan, K.; Jayadevan, N.C.

1993-01-01

Chemical characterization of rubidium uranium(IV) trisulfate, RB 2 U(SO 4 ) 3 , a new chemical assay standard for uranium requires accurate analysis of rubidium. A gravimetric and an X-ray fluorescence method (XRF) for the determination of rubidium in this compound are described. In the gravimetric method, rubidium is determined as Rb 2 Na[Co(NO 2 ) 6 ].H 2 O without separating uranium with a precision of the order of ±0.5%. In the XRF method, the concentration ratio of rubidium to uranium, C Rb /C U , is determined in the solid samples by the binary ratio method using calibration between intensity ratios (I Rb /I U ) and concentration ratios (C Rb /C U ). (author) 6 refs.; 2 figs.; 3 tabs

Investigation into scanning tunnelling luminescence microscopy

International Nuclear Information System (INIS)

Manson-Smith, S.K.

2001-01-01

This work reports on the development of a scanning tunnelling luminescence (STL) microscope and its application to the study of Ill-nitride semiconductor materials used in the production of light emitting devices. STL microscopy is a technique which uses the high resolution topographic imaging capabilities of the scanning tunnelling microscope (STM) to generate high resolution luminescence images. The STM tunnelling current acts as a highly localised source of electrons (or holes) which generates luminescence in certain materials. Light generated at the STM tunnelling junction is collected concurrently with the height variation of the tunnelling probe as it is scanned across a sample surface, producing simultaneous topographic and luminescence images. Due to the very localised excitation source, high resolution luminescence images can be obtained. Spectroscopic resolution can be obtained by using filters. Additionally, the variation of luminescence intensity with tunnel current and with bias voltage can provide information on recombination processes and material properties. The design and construction of a scanning tunnelling luminescence microscope is described in detail. Operating under ambient conditions, the microscope has several novel features, including a new type of miniature inertial slider-based approach motor, large solid-angle light collection optical arrangement and a tip-height regulation system which requires the minimum of operator input. (author)

Polymeric Luminescent Compositions Doped with Beta-Diketonates Boron Difluoride as Material for Luminescent Solar Concentrator

Science.gov (United States)

Khrebtov, A. A.; Fedorenko, E. V.; Reutov, V. A.

2017-11-01

In this paper we investigated polymeric luminescent compositions based on polystyrene doped with beta diketonates boron difluoride. Transparent films with effective absorption in the ultraviolet and blue regions of the spectrum were obtained. Polymeric luminescent compositions based on the mixture of dyes allow expanding the absorption region and increase the radiation shift. A luminescent solar concentrator consisting of a glass plate coated with such film can be used for photovoltaic window application.

Luminescence sensitivity changes in quartz

CERN Document Server

Wintle, A G

1999-01-01

In the luminescence dating of sedimentary or heated quartz, some heat treatment is usually applied to the sample immediately prior to the measurement of the optically stimulated luminescence. In this paper we report experiments on a 30,000-year-old sedimentary quartz, in which we use the luminescence response to a test dose to monitor the changes in sensitivity that are caused by holding the quartz at temperatures from 160 to 280 deg. C for times from 10 s to 22 h. For an optically bleached sample, the monitoring is by both optically stimulated luminescence and the 110 deg. C TL peak; both luminescence signals are shown to have the same sensitisation (i.e. activation energy) characteristics. For natural or laboratory irradiated samples only the 110 deg. C TL peak can be used; sensitivity increases of up to a factor of 1.3 and 3 are observed for the natural and laboratory irradiated aliquots, respectively. Up to four exponential components are used to deconvolve the sensitivity change data; the dominant compon...

Thermal and electron stimulated luminescence of natural bones, commercial hydroxyapatite and collagen.

Science.gov (United States)

Roman-Lopez, J; Correcher, V; Garcia-Guinea, J; Rivera, T; Lozano, I B

2014-01-01

The luminescence (cathodoluminescence and thermoluminescence) properties of natural bones (Siberian mammoth and adult elephant), commercial hydroxyapatite and collagen were analyzed. Chemical analyses of the natural bones were determined using by Electron Probe Micro-Analysis (EMPA). Structural, molecular and thermal characteristics were determined by X-ray Diffraction (XRD), Raman spectroscopy and Differential Thermal and Thermogravimetric analysis (DTA-TG). Cathodoluminescence (CL) spectra of natural bones and collagen showed similar intense broad bands at 440 and 490 nm related to luminescence of the tetrahedral anion [Formula: see text] or structural defects. A weaker luminescence exhibited at 310 nm could be attributed to small amount of rare earth elements (REEs). Four luminescent bands at 378, 424, 468 and 576 nm were observed in the commercial hydroxyapatite (HAP). Both natural bones and collagen samples exhibited natural thermoluminescence (NTL) with well-defined glow curves whereas that the induced thermoluminescence (ITL) only appears in the samples of commercial hydroxyapatite and collagen. Additional explanations for the TL anomalous fading of apatite, as a crucial difficulty performing dosimetry and dating, are also considered. Copyright © 2013 Elsevier B.V. All rights reserved.

Plasmon-enhanced optically stimulated luminescence

International Nuclear Information System (INIS)

Guidelli, E. J.; Baffa, O.; Ramos, A. P.

2015-10-01

Full text: Optically Stimulated Luminescence dosimeters (OSLD) have been largely used for personal, medical, and industrial radiation dosimetry. Developing highly sensitive and small-sized radiation detectors and dosimeters is essential for improving spatial resolution and consequently diagnosis quality and treatment efficacy in the case of applications in radiodiagnosis and radiation therapy, for instance. Conventional methods to improve the OSLD sensitivity consist of doping and co-doping the host materials with atoms of other elements, thereby increasing the amount of trapping and/or luminescent centers. Our group is researching on the use of the plasmon properties of noble metal nanoparticles to increase OSL intensity. Upon incidence of a light beam with appropriate resonant wavelengths, the oscillation of the free electrons at the nanoparticle surface originates the Localized Surface Plasmons (LSP) and the consequent plasmon resonance band. The interaction between the LSP and the surrounding luminescent material leads to new optical properties largely employed for enhancing several luminescent processes. Here we will show our results regarding the use of LSP to increase OSLD sensitivity. The interaction between the traps/luminescent centers and the plasmons depends on the distance between them, on the plasmon resonance band intensity and position, as well as on the surrounding medium. Therefore, the plasmon-enhanced luminescence is a promising tool to develop more sensitive and miniaturized OSLD. (Author)

Plasmon-enhanced optically stimulated luminescence

Energy Technology Data Exchange (ETDEWEB)

Guidelli, E. J.; Baffa, O. [Universidade de Sao Paulo, Faculdade de Filosofia, Ciencias e Letras de Ribeirao Preto, Departamento de Fisica, Av. Bandeirantes 3900, 14040-901 Ribeirao Preto, Sao Paulo (Brazil); Ramos, A. P., E-mail: ederguidelli@gmail.com [Universidade de Sao Paulo, Faculdade de Filosofia, Ciencias e Letras de Ribeirao Preto, Departamento de Quimica, Av. Bandeirantes 3900, 14040-901 Ribeirao Preto, Sao Paulo (Brazil)

2015-10-15

Full text: Optically Stimulated Luminescence dosimeters (OSLD) have been largely used for personal, medical, and industrial radiation dosimetry. Developing highly sensitive and small-sized radiation detectors and dosimeters is essential for improving spatial resolution and consequently diagnosis quality and treatment efficacy in the case of applications in radiodiagnosis and radiation therapy, for instance. Conventional methods to improve the OSLD sensitivity consist of doping and co-doping the host materials with atoms of other elements, thereby increasing the amount of trapping and/or luminescent centers. Our group is researching on the use of the plasmon properties of noble metal nanoparticles to increase OSL intensity. Upon incidence of a light beam with appropriate resonant wavelengths, the oscillation of the free electrons at the nanoparticle surface originates the Localized Surface Plasmons (LSP) and the consequent plasmon resonance band. The interaction between the LSP and the surrounding luminescent material leads to new optical properties largely employed for enhancing several luminescent processes. Here we will show our results regarding the use of LSP to increase OSLD sensitivity. The interaction between the traps/luminescent centers and the plasmons depends on the distance between them, on the plasmon resonance band intensity and position, as well as on the surrounding medium. Therefore, the plasmon-enhanced luminescence is a promising tool to develop more sensitive and miniaturized OSLD. (Author)

Precise and efficient evaluation of gravimetric quantities at arbitrarily scattered points in space

Science.gov (United States)

Ivanov, Kamen G.; Pavlis, Nikolaos K.; Petrushev, Pencho

2017-12-01

Gravimetric quantities are commonly represented in terms of high degree surface or solid spherical harmonics. After EGM2008, such expansions routinely extend to spherical harmonic degree 2190, which makes the computation of gravimetric quantities at a large number of arbitrarily scattered points in space using harmonic synthesis, a very computationally demanding process. We present here the development of an algorithm and its associated software for the efficient and precise evaluation of gravimetric quantities, represented in high degree solid spherical harmonics, at arbitrarily scattered points in the space exterior to the surface of the Earth. The new algorithm is based on representation of the quantities of interest in solid ellipsoidal harmonics and application of the tensor product trigonometric needlets. A FORTRAN implementation of this algorithm has been developed and extensively tested. The capabilities of the code are demonstrated using as examples the disturbing potential T, height anomaly ζ , gravity anomaly Δ g , gravity disturbance δ g , north-south deflection of the vertical ξ , east-west deflection of the vertical η , and the second radial derivative T_{rr} of the disturbing potential. After a pre-computational step that takes between 1 and 2 h per quantity, the current version of the software is capable of computing on a standard PC each of these quantities in the range from the surface of the Earth up to 544 km above that surface at speeds between 20,000 and 40,000 point evaluations per second, depending on the gravimetric quantity being evaluated, while the relative error does not exceed 10^{-6} and the memory (RAM) use is 9.3 GB.

Some technical details concerning a new method of gravimetric-seismic inversion

DEFF Research Database (Denmark)

Strykowski, Gabriel

1999-01-01

In this paper a number of technical details related to a new method of gravimetric-seismic inversion, which is still under development, are explained. Although the present contribution aims on providing general statements on how to formulate and solve complex gravimetric-seismic modeling; problems......, the inspiration comes from the practical modeling problems in the area of Jutland peninsula (Denmark). More specifically, the methodological aspects of the proposed inversion method are illustrated on a problem of 3D modeling of the intra crustal intrusion associated with the Silkeborg Gravity High. The existing...... refraction seismic profile locates the source of the anomaly in depths 10 km - 18 km. In an earlier publication, (Strykowski, 1998), and for the same test area, a method of complex geological stripping is described. The present contribution is a continuation of this paper in the direction of inversion...

Luminescence of LiH(D):Ru monocrystals

International Nuclear Information System (INIS)

Sabirzyanov, A.A.; Oparin, D.V.; Pilipenko, G.I.; Gavrilov, F.F.

1993-01-01

Luminescence of lithium hydride (deuteride) activated by ruthenium is recorded for the first time. The features connected with the structure and oscillations of the basic lattice are detected in luminescence spectrum. The qualitative model of luminescence spectrum is suggested

Time-resolved infrared stimulated luminescence signals in feldspars: Analysis based on exponential and stretched exponential functions

International Nuclear Information System (INIS)

Pagonis, V.; Morthekai, P.; Singhvi, A.K.; Thomas, J.; Balaram, V.; Kitis, G.; Chen, R.

2012-01-01

Time-resolved infrared-stimulated luminescence (TR-IRSL) signals from feldspar samples have been the subject of several recent experimental studies. These signals are of importance in the field of luminescence dating, since they exhibit smaller fading effects than the commonly employed continuous-wave infrared signals (CW-IRSL). This paper presents a semi-empirical analysis of TR-IRSL data from feldspar samples, by using a linear combination of exponential and stretched exponential (SE) functions. The best possible estimates of the five parameters in this semi-empirical approach are obtained using five popular commercially available software packages, and by employing a variety of global optimization techniques. The results from all types of software and from the different fitting algorithms were found to be in close agreement with each other, indicating that a global optimum solution has likely been reached during the fitting process. Four complete sets of TR-IRSL data on well-characterized natural feldspars were fitted by using such a linear combination of exponential and SE functions. The dependence of the extracted fitting parameters on the stimulation temperature is discussed within the context of a recently proposed model of luminescence processes in feldspar. Three of the four feldspar samples studied in this paper are K-rich, and these exhibited different behavior at higher stimulation temperatures, than the fourth sample which was a Na-rich feldspar. The new method of analysis proposed in this paper can help isolate mathematically the more thermally stable components, and hence could lead to better dating applications in these materials. - Highlights: ► TR-IRSL from four feldspars were analyzed using exponential and stretched exponential functions. ► A variety of global optimization techniques give good agreement. ► Na-rich sample behavior is different from the three K-rich samples. ► Experimental data are fitted for stimulation temperatures

Material for a luminescent solar concentrator

Science.gov (United States)

Andrews, L.J.

1984-01-01

A material for use in a luminescent solar concentrator, formed by ceramitizing the luminescent ion Cr/sup 3 +/ with a transparent ceramic glass containing mullite. The resultant material has tiny Cr/sup 3 +/-bearing crystallites dispersed uniformly through an amorphous glass. The invention combines the high luminescent efficiency of Cr/sup 3 +/ in the crystalline phase with the practical and economical advantages of glass technology.

Virulence of luminescent and non-luminescent isogenic vibrios towards gnotobiotic Artemia franciscana larvae and specific pathogen-free Litopenaeus vannamei shrimp.

Science.gov (United States)

Phuoc, L H; Defoirdt, T; Sorgeloos, P; Bossier, P

2009-04-01

This study was conducted to test the virulence of luminescent (L) and non-luminescent (NL) isogenic strains of Vibrio campbellii LMG21363, Vibrio harveyi BB120 (wild type) and quorum-sensing mutant strains derived from the wild type such as Vibrio harveyi BB152, BB170, MM30 and BB886. The NL strains could be obtained by culturing rifampicin-resistant luminescent strains in the dark under static condition. The virulence of the L and NL strains was tested in gnotobiotic Artemia franciscana larvae challenged with 10(4) CFU ml(-1) of bacteria. All luminescent isogenic tested strains showed higher virulence compared to the NL strains. The virulence of L and NL V. campbellii and V. harveyi BB120 was also tested in specific pathogen-free juvenile shrimp upon intramuscular injection with 10(6) CFU of bacteria. In contrast with Artemia, there was no significant difference in mortality between the groups challenged with L and NL strains (P > 0.05). The non-luminescent strains were not able to revert back to the luminescent state and quorum sensing did not influence this phenotypic shift. Luminescent Vibrio strains can switch to a non-luminescent state by culturing them in static conditions. The NL strains become less virulent as verified in Artemia. The luminescent state of Vibrio cells in a culture needs to be verified in order to assure maintenance of virulence.

Gravimetric preparation and characterization of primary reference solutions of molybdenum and rhodium.

Science.gov (United States)

Kaltenbach, Angela; Noordmann, Janine; Görlitz, Volker; Pape, Carola; Richter, Silke; Kipphardt, Heinrich; Kopp, Gernot; Jährling, Reinhard; Rienitz, Olaf; Güttler, Bernd

2015-04-01

Gravimetrically prepared mono-elemental reference solutions having a well-known mass fraction of approximately 1 g/kg (or a mass concentration of 1 g/L) define the very basis of virtually all measurements in inorganic analysis. Serving as the starting materials of all standard/calibration solutions, they link virtually all measurements of inorganic analytes (regardless of the method applied) to the purity of the solid materials (high-purity metals or salts) they were prepared from. In case these solid materials are characterized comprehensively with respect to their purity, this link also establishes direct metrological traceability to The International System of Units (SI). This, in turn, ensures the comparability of all results on the highest level achievable. Several national metrology institutes (NMIs) and designated institutes (DIs) have been working for nearly two decades in close cooperation with commercial producers on making an increasing number of traceable reference solutions available. Besides the comprehensive characterization of the solid starting materials, dissolving them both loss-free and completely under strict gravimetric control is a challenging problem in the case of several elements like molybdenum and rhodium. Within the framework of the European Metrology Research Programme (EMRP), in the Joint Research Project (JRP) called SIB09 Primary standards for challenging elements, reference solutions of molybdenum and rhodium were prepared directly from the respective metals with a relative expanded uncertainty associated with the mass fraction of U rel(w) methods required to assist with the preparation and as dissemination tools.

Uncertainty associated with assessing semen volume: are volumetric and gravimetric methods that different?

Science.gov (United States)

Woodward, Bryan; Gossen, Nicole; Meadows, Jessica; Tomlinson, Mathew

2016-12-01

The World Health Organization laboratory manual for the examination of human semen suggests that an indirect measurement of semen volume by weighing (gravimetric method) is more accurate than a direct measure using a serological pipette. A series of experiments were performed to determine the level of discrepancy between the two methods using pipettes and a balance which had been calibrated to a traceable standard. The median weights of 1.0ml and 5.0ml of semen were 1.03 g (range 1.02-1.05 g) and 5.11 g (range 4.95-5.16 g), respectively, suggesting a density for semen between 1.03g and 1.04 g/ml. When the containers were re-weighed after the removal of 5.0 ml semen using a serological pipette, the mean residual loss was 0.12 ml (120 μl) or 0.12 g (median 100 μl, range 70-300 μl). Direct comparison of the volumetric and gravimetric methods in a total of 40 samples showed a mean difference of 0.25ml (median 0.32 ± 0.67ml) representing an error of 8.5%. Residual semen left in the container by weight was on average 0.11 g (median 0.10 g, range 0.05-0.19 g). Assuming a density of 1 g/ml then the average error between volumetric and gravimetric methods was approximately 8% (p gravimetric measurement of semen volume. Laboratories may therefore prefer to provide in-house quality assurance data in order to be satisfied that 'estimating' semen volume is 'fit for purpose' as opposed to assuming a lower uncertainty associated with the WHO recommended method.

Luminescence of uranyl ion complexed with 2,6-pyridine dicarboxylic acid as ligand in acetonitrile medium. Observation of co-luminescence

Energy Technology Data Exchange (ETDEWEB)

Maji, Siuli; Kumar, Satendra; Sankaran, Kannan [Indira Ghandi Centre for Atomic Research, Tamil Nadu (India). Materials Chemistry Div.

2017-10-01

Luminescence from UO{sub 2}{sup 2+} (uranyl ion) complexed with 2,6-pyridine dicarboxylic acid (PDA) has been studied using acetonitrile (MeCN) as solvent between pH 1.0 and 6.0. The enhancement in luminescence intensity because of sensitization by PDA in the non-aqueous environment provided by the MeCN is found to be one order better than in aqueous medium. The luminescence is further enhanced by about four times following the addition of Y{sup 3+}; a process known as co-luminescence. This is the first study on co-luminescence of uranyl ion in its PDA complex. Lifetime studies indicate the presence of two species having different micro-environments. Formations of both intra and inter molecular complexes are believed to be responsible for enhancement due to co-luminescence.

Luminescence of uranyl ion complexed with 2,6-pyridine dicarboxylic acid as ligand in acetonitrile medium. Observation of co-luminescence

International Nuclear Information System (INIS)

Maji, Siuli; Kumar, Satendra; Sankaran, Kannan

2017-01-01

Luminescence from UO_2"2"+ (uranyl ion) complexed with 2,6-pyridine dicarboxylic acid (PDA) has been studied using acetonitrile (MeCN) as solvent between pH 1.0 and 6.0. The enhancement in luminescence intensity because of sensitization by PDA in the non-aqueous environment provided by the MeCN is found to be one order better than in aqueous medium. The luminescence is further enhanced by about four times following the addition of Y"3"+; a process known as co-luminescence. This is the first study on co-luminescence of uranyl ion in its PDA complex. Lifetime studies indicate the presence of two species having different micro-environments. Formations of both intra and inter molecular complexes are believed to be responsible for enhancement due to co-luminescence.

Comparison of Metal-on-Metal Hip Simulator Wear Measured by Gravimetric, CMM and Optical Profiling Methods

OpenAIRE

Alberts, Larry Russell; Martinez-Nogues, Vanesa; Cook, Richard; Maul, Christian; Bills, Paul J.; Racasan, Radu; Stolz, Martin; Wood, Robert J. K.

2018-01-01

Simulation of wear in artificial joint implants is critical for evaluating implant designs and materials. Traditional protocols employ the gravimetric method to determine the loss of material by measuring the weight of the implant components before and after various test intervals and after the completed test. However, the gravimetric method cannot identify the location, area coverage or maximum depth of the wear and it has difficulties with proportionally small weight changes in relatively h...

Erosion of water-based cements evaluated by volumetric and gravimetric methods.

Science.gov (United States)

Nomoto, Rie; Uchida, Keiko; Momoi, Yasuko; McCabe, John F

2003-05-01

To compare the erosion of glass ionomer, zinc phosphate and polycarboxylate cements using volumetric and gravimetric methods. For the volumetric method, the eroded depth of cement placed in a cylindrical cavity in PMMA was measured using a dial gauge after immersion in an eroding solution. For the gravimetric method, the weight of the residue of a solution in which a cylindrical specimen had been immersed was measured. 0.02 M lactic acid solution (0.02 M acid) and 0.1 M lactic acid/sodium lactate buffer solution (0.1 M buffer) were used as eroding solutions. The pH of both solutions was 2.74 and the test period was 24 h. Ranking of eroded depth and weight of residue was polycarboxylate>zinc phosphate>glass ionomers. Differences in erosion were more clearly defined by differences in eroded depth than differences in weight of residue. In 0.02 M acid, the erosion of glass ionomer using the volumetric method was effected by the hygroscopic expansion. In 0.1 M buffer, the erosion for polycarboxylate and zinc phosphate using the volumetric method was much greater than that using the gravimetric method. This is explained by cryo-SEM images which show many holes in the surface of specimens after erosion. It appears that zinc oxide is dissolved leaving a spongy matrix which easily collapses under the force applied to the dial gauge during measurement. The volumetric method that employs eroded depth of cement using a 0.1 M buffer solution is able to quantify erosion and to make material comparisons.

Receptor-Targeted Luminescent Silver Bionanoparticles

NARCIS (Netherlands)

Bunschoten, Anton; Chin, Patrick T.K.; Buckle, Tessa; Linden, van der Marte; Barendregt, Arjan; Verheijen, Marcel A.; Leeuwen, van Fijs W.B.

2016-01-01

Luminescent Ag nanoclusters (Ag-NC) provide the next generation in bionanoparticles, wherein the luminescence (650 nm) and large Stokes shift of these inorganic nanoclusters are favorable for biological imaging. By combining these characteristics with those of human serum albumin (HSA; a protein

Dating Last Interglacial Coastal Systems Using New Feldspar Luminescence Technologies

Science.gov (United States)

Lamothe, M.

2017-12-01

The recent explosion in new luminescence dating technologies offers new opportunities to explore Quaternary marine coastal facies and landforms. However, tectonic and climatic processes controlling the development of Pleistocene coastal lithosomes are commonly obscured by their poorly constrained geological age. Luminescence dating of feldspar probes one order of magnitude deeper into geological time than radiocarbon and more than 5 times the current age range of quartz optically-stimulated luminescence, routinely used in luminescence dating. However, feldspar luminescence stimulated by infrared photons (eg IRSL) is hampered by anomalous fading. Successful correction methods developed by us over the last 15 years did produce sound chronologies but the fading-corrected ages carried large uncertainties. New approaches initiated by other laboratories, mainly in Europe, have isolated high temperature post-IRSL luminescence as this signal seems to be only slightly affected by fading. However, the gain in stability seems to be lessened due to bleachibility issues, generating age overestimations. We developed a novel protocol known as post-isothermal IRSL dating (Pit-IR) that focuses on a dual system of luminescence signals, probing low (50C) and medium (225C) temperature IRSL signals following isothermal treatments of various intensities. These protocols have been tested on Last interglacial coastal sediments in strikingly different GIA contexts along the Atlantic coastal areas of SE USA as well as from Morocco, Brazil and LIG sites in the Mediterranean basin. A systematic analysis of these results would suggest that a) falling-stages sequences are more commonly preserved as the OSL/IRSL ages are preferentially dating from the end of the MIS5e high stand and b) MIS5a marine sediments may be detectable away from areas generally thought to be affected by peripheral bulge collapse.

Reflection measurements for luminescent powders

Science.gov (United States)

Kroon, R. E.

2018-04-01

Luminescent materials are useful in applications varying from lighting and display technologies to document security features and medical research, amongst many others. Measurement of the excitation range is an important consideration, and absorption bands are often determined from a decrease in the measured diffuse reflectance of the material using a ultraviolet-visible (UV-vis) spectrophotometer with an integrating sphere. Such a system may provide questionable results when used to measure the reflectance of a luminescence material, which is demonstrated for a Tb doped silica phosphor, because the system cannot differentiate between the reflected light and luminescence. It is shown that more reliable results are achieved for this phosphor by measuring the reflectance using a synchronous zero-offset scan in a fluorescence spectrometer equipped with an integrating sphere. This method is therefore recommended instead of traditional reflectance measurements using a UV-vis spectrophotometer for luminescent powders.

Near-Infrared Quantum Cutting Long Persistent Luminescence

OpenAIRE

Zou, Zehua; Feng, Lin; Cao, Cheng; Zhang, Jiachi; Wang, Yuhua

2016-01-01

By combining the unique features of the quantum cutting luminescence and long persistent luminescence, we design a new concept called ?near-infrared quantum cutting long persistent luminescence (NQPL)?, which makes it possible for us to obtain highly efficient (>100%) near-infrared long persistent luminescence in theory. Guided by the NQPL concept, we fabricate the first NQPL phosphor Ca2Ga2GeO7:Pr3+,Yb3+. It reveals that both the two-step energy transfer of model (I) and the one-step energy ...

Crustal thickness of Antarctica estimated using data from gravimetric satellites

Science.gov (United States)

Llubes, Muriel; Seoane, Lucia; Bruinsma, Sean; Rémy, Frédérique

2018-04-01

Computing a better crustal thickness model is still a necessary improvement in Antarctica. In this remote continent where almost all the bedrock is covered by the ice sheet, seismic investigations do not reach a sufficient spatial resolution for geological and geophysical purposes. Here, we present a global map of Antarctic crustal thickness computed from space gravity observations. The DIR5 gravity field model, built from GOCE and GRACE gravimetric data, is inverted with the Parker-Oldenburg iterative algorithm. The BEDMAP products are used to estimate the gravity effect of the ice and the rocky surface. Our result is compared to crustal thickness calculated from seismological studies and the CRUST1.0 and AN1 models. Although the CRUST1.0 model shows a very good agreement with ours, its spatial resolution is larger than the one we obtain with gravimetric data. Finally, we compute a model in which the crust-mantle density contrast is adjusted to fit the Moho depth from the CRUST1.0 model. In East Antarctica, the resulting density contrast clearly shows higher values than in West Antarctica.

Enhancing and quenching luminescence with gold nanoparticle films: the influence of substrate on the luminescent properties

International Nuclear Information System (INIS)

Guidelli, Eder José; Baffa, Oswaldo; Ramos, Ana Paula

2016-01-01

Gold nanoparticle (AuNP) films were sputtered over glass and aluminum substrates to enhance optically stimulated luminescence (OSL), a luminescent technique employed for radiation detection, from x-ray irradiated NaCl nanocrystals. The AuNP films deposited over glass led to enhanced-OSL emission, whereas the AuNP films deposited on aluminum substrates quenched the OSL emission. The enhanced-OSL intensity is proportional to the optical density of the film's plasmon resonance band at the stimulation wavelength. For the case of the AuNP/aluminum films, the luminescence quenching diminishes, and OSL intensity partially recovers upon increasing the distance between the AuNPs and the aluminum substrates, and between the luminescent nanocrystals and the AuNP films. These results suggest that plasmonic interactions between the emitter nanocrystals, the localized surface plasmons (LSP) of the AuNPs, and the substrate are responsible for the OSL enhancement and quenching. In this sense, the substrate dictates whether LSP relaxation occurs by radiative or non-radiative transisitions, leading to enhanced or quenched OSL, respectively. Therefore, besides showing that AuNP films can enhance and/or tune the sensitivity of luminescent radiation detectors, and demonstrating OSL as a new technique to investigate mechanisms of plasmon-enhanced luminescence, these results bring insights on how substrates strongly modify the optical properties of AuNP films. (paper)

Luminescence dating of Netherland's sediments

NARCIS (Netherlands)

Wallinga, J.; Davids, F.; Dijkmans, J.W.A.

2007-01-01

Over the last decades luminescence dating techniques have been developed that allow earth scientists to determine the time of deposition of sediments. In this contribution we revity: 1) the development of the methodology, 2) tests of the reliability of luminescence dating on Netherlands' sediments;

Luminescence enhancement of uranyl ion by benzoic acid in acetonitrile

International Nuclear Information System (INIS)

Satendra Kumar; Maji, S.; Joseph, M.; Sankaran, K.

2014-01-01

Uranyl ion is known for its characteristic green luminescence and therefore luminescence spectroscopy is a suitable technique for characterizing different uranyl species. In aqueous medium, luminescence of uranyl ion is generally weak due to its quenching by water molecules and therefore in order to enhance the luminescence of uranyl ion in aqueous medium, luminescence enhancing reagents such as H 3 PO 4 , H 2 SO 4 , HCIO 4 have been widely used. The other method to enhance the uranyl luminescence is by ligand sensitized luminescence, a method well established for lanthanides. In this work, luminescence of uranyl ion is found to be enhanced by benzoic acid in acetonitrile medium. In aqueous medium benzoic acid does not enhance the uranyl luminescence although it forms 1:1 and 1:2 complexes with uranyl ion. Luminescence spectra of uranyl benzoate revealed that enhancement is due to sensitization of uranyl luminescence by benzoate ions. UV-Vis spectroscopy has been utilized to characterize the specie formed in the in acetonitrile medium. UV-Vis spectroscopy along with luminescence spectra revealed that the specie to be tribenzoate complex of uranyl (UO 2 (C 6 H 5 COO) 3 ) - having D 3 h symmetry. (author)

Use of sulfoxides for extraction-gravimetric determination of niobium and tantalum

International Nuclear Information System (INIS)

Nikolaev, A.I.; Babkin, A.G.; Tkachenko, V.G.

1977-01-01

An extraction-gravimetrical technique has been developed for determination of niobium and tantalum. The technique permits simultaneous extraction of tantalum and its concentrating in the aqueous phase; the range of Ta concentrations determined is essentially wider than in case of the routine gravimetric methods. The technique is based upon the fact, that tantalum is extracted by sulfoxides from fluorine-sulphate solutions at lower concentration of Hf and at lower ratios between the volumes of organic and aqueous phases than niobium. Two subsequent extractions by 1M sulfoxide solutions provide for practically complete transfer of tantalum into the organic phase, whereas extraction of niobium is only 3-20%. Sufficient recovery of Ta and Nb from organic phases is provided by re-extraction by NH 4 F solution. The technique is suitable for niobium and tantalum determination at the ratios of their pentoxides from 1:100 to 100:1. The disturbing influence of Fe(3) is suppressed by reductions to Fe(2)

Gravimetric determination of uranium(VI) and thorium(IV) with substituted pyrazolones

International Nuclear Information System (INIS)

Arora, H.C.; Rao, G.N.

1981-01-01

4-Acylpyrazolones like 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone (PMBP), 1-phenyl-3-methyl-4-p-nitrobenzoyl-5-pyrazolone (PMNP) and 1-phenyl-3-methyl-4-(3,5 dinitrobenzoyl)-5-pyrazolone (PMDP) have been synthesized and developed as gravimetric reagents for the determination of U(VI) and Th(IV). Uranium(VI) is almost quantitatively precipitated with PMBP, PMNP, and PMDP at pH 2.20, 1.85 and 1.70 respectively. The pH values for the complete precipitation of thorium(IV) with PMBP, PMNP and PMDP are 2.90, 2.75 and 2.50 respectively. PMBP has proved to be an efficient ligand for gravimetric determination of U(VI) by direct weighing method after drying at 100 +- 10 deg C. The percentage relative error varies from 0.4 to 1.6 in the determination of U(VI) by this method. The effect of a number of interfering ions on the precipitation of U(VI) by PMBP has been reported. (author)

Recent developments in luminescent solar concentrators

Science.gov (United States)

van Sark, W. G. J. H. M.

2014-10-01

High efficiency photovoltaic devices combine full solar spectrum absorption and effective generation and collection of charge carriers, while commercial success depends on cost effectiveness in manufacturing. Spectrum modification using down shifting has been demonstrated in luminescent solar concentrators (LSCs) since the 1970s, as a cheap alternative for standard c-Si technology. LSCs consist of a highly transparent plastic plate, in which luminescent species are dispersed, which absorb incident light and emit light at a red-shifted wavelength, with high quantum efficiency. Material issues have hampered efficiency improvements, in particular re-absorption of light emitted by luminescent species and stability of these species. In this contribution, approaches are reviewed on minimizing re-absorption, which should allow surpassing the 10% luminescent solar concentrator efficiency barrier.

Review of present trends in luminescence research

International Nuclear Information System (INIS)

Williams, F.; Delaware Univ., Newark

1981-01-01

The difficulties of a comprehensive review of the broad and diverse branches of molecular and solid-state luminescence research are noted. This review is thus limited to selective topics. Some general concepts and trends are then introduced, including: luminescence excitation as a collective excitation of a many-body problem, encompassing in some cases the source and probe in its formulation; continuing trends towards extremal conditions of experiments and towards inhomogeneous and structured materials, from man-made superlattices to biological materials; and increased attention to applications of luminescence research to lamps, displays, solar devices and biological research. Representative recent and new specific research areas include: site selection spectroscopy and 'hole burning'; picosecond delayed coherent anti-Stokes Raman scattering; computer simulation of dynamical processes in luminescence; electron-hole expansion from the Fermi pressure of e-h plasmas; and hot electron phenomena and hot luminescence. Finally some pending problems in luminescence research, such as reconciling the configuration coordinate model and the electronic band theory and clarifying multi-phonon non-radiative processes, are discussed. (orig.)

Luminescence imaging of water during alpha particle irradiation

Science.gov (United States)

Yamamoto, Seiichi; Komori, Masataka; Koyama, Shuji; Toshito, Toshiyuki

2016-05-01

The luminescence imaging of water using the alpha particle irradiation of several MeV energy range is thought to be impossible because this alpha particle energy is far below the Cerenkov-light threshold and the secondary electrons produced in this energy range do not emit Cerenkov-light. Contrary to this consensus, we found that the luminescence imaging of water was possible with 5.5 MeV alpha particle irradiation. We placed a 2 MBq of 241Am alpha source in water, and luminescence images of the source were conducted with a high-sensitivity, cooled charge-coupled device (CCD) camera. We also carried out such imaging of the alpha source in three different conditions to compare the photon productions with that of water, in air, with a plastic scintillator, and an acrylic plate. The luminescence imaging of water was observed from 10 to 20 s acquisition, and the intensity was linearly increased with time. The intensity of the luminescence with the alpha irradiation of water was 0.05% of that with the plastic scintillator, 4% with air, and 15% with the acrylic plate. The resolution of the luminescence image of water was better than 0.25 mm FWHM. Alpha particles of 5.5 MeV energy emit luminescence in water. Although the intensity of the luminescence was smaller than that in air, it was clearly observable. The luminescence of water with alpha particles would be a new method for alpha particle detection and distribution measurements in water.

Luminescence imaging of water during alpha particle irradiation

Energy Technology Data Exchange (ETDEWEB)

Yamamoto, Seiichi, E-mail: s-yama@met.nagoya-u.ac.jp [Radiological and Medical Laboratory Sciences, Nagoya University Graduate School of Medicine (Japan); Komori, Masataka; Koyama, Shuji [Radiological and Medical Laboratory Sciences, Nagoya University Graduate School of Medicine (Japan); Toshito, Toshiyuki [Department of Proton Therapy Physics, Nagoya Proton Therapy Center, Nagoya City West Medical Center (Japan)

2016-05-21

The luminescence imaging of water using the alpha particle irradiation of several MeV energy range is thought to be impossible because this alpha particle energy is far below the Cerenkov-light threshold and the secondary electrons produced in this energy range do not emit Cerenkov-light. Contrary to this consensus, we found that the luminescence imaging of water was possible with 5.5 MeV alpha particle irradiation. We placed a 2 MBq of {sup 241}Am alpha source in water, and luminescence images of the source were conducted with a high-sensitivity, cooled charge-coupled device (CCD) camera. We also carried out such imaging of the alpha source in three different conditions to compare the photon productions with that of water, in air, with a plastic scintillator, and an acrylic plate. The luminescence imaging of water was observed from 10 to 20 s acquisition, and the intensity was linearly increased with time. The intensity of the luminescence with the alpha irradiation of water was 0.05% of that with the plastic scintillator, 4% with air, and 15% with the acrylic plate. The resolution of the luminescence image of water was better than 0.25 mm FWHM. Alpha particles of 5.5 MeV energy emit luminescence in water. Although the intensity of the luminescence was smaller than that in air, it was clearly observable. The luminescence of water with alpha particles would be a new method for alpha particle detection and distribution measurements in water.

Three years of high precision gravity measurements at the gravimetric station of Brasimone - Italy

Directory of Open Access Journals (Sweden)

G. Casula

1998-06-01

Full Text Available From August 1995 up to now, at the Enea Research Center of Brasimone, in the Italian Apennines between Bologna and Florence (Italy: 44º07'N, 11º.07'E, 890 m height, the superconducting gravimeter GWR model TT70 number T015 has been continuously recording the variation of the local gravity field, in the frame of the Global Geodynamics Project. The gravimetric laboratory, being a room of the disused nuclear power plant of Brasimone, is a very stable site, free from noise due to human activities. Data blocks of several months of continuous gravity records have been collected over a time span of three years, together with the meteorological data. The gravimeter has been calibrated at relative accuracy better than 0.3% with the aid of a mobile mass system, by imposed perturbations of the local gravity field and recording the gravimeter response. The results of this calibration technique were checked by two comparison experiments with absolute gravimeters performed during this period: the first, in May 1994 with the aid of the symmetrical rise and fall gravimeter of the Institute of Metrology Colonnetti of Turin, and the second in October 1997 involving an FG5 absolute gravimeter of the Institute de Physique du Globe of Strasbourg. The gravimeter signal was analysed to compute a high precision tidal model for Brasimone site. Starting from a set of gravimetric and atmospheric pressure data of high quality, relative to 46 months of observation, we performed the tidal analysis using Eterna 3.2 software to compute amplitudes, gravimetric factors and phases of the main waves of the Tamura catalogue. Finally a comparison experiment between two of the STS-1/VBB broadband seismometers of the MedNet project network and the gravity records relative to the Balleny Islands earthquake (March 25, 1998 were analysed to look for evidence of normal modes due to the free oscillations of the Earth.

Towards Luminescence Dating Of Mosaic Glass

Science.gov (United States)

Galli, A.; Martini, M.; Sibila, E.; Villa, I.

The possibility of dating archaeological glass by means of luminescent techniques has been investigated in recent years, despite the difficulties of this application, mainly linked to the amorphous structure of the material. We focused in particular on mosaic glass, after the encouraging results obtained on byzantine and medieval samples. Further studies were devoted to the comprehension of the luminescent mechanisms in silica glasses, and to the investigation of the relationships between luminescence, colouring or opacifier ions and crystalline phase of the vitreous matrix. The results of a study on the dosimetric characteristics of thermoluminescence (TL) and Optically Stimulated Luminescence (OSL) of a few medieval blue-green mosaic glasses from the San Lorenzo church (Milan) are presented, and the experimental protocols established to identify their suitability for dating are discussed.

Humidity and Gravimetric Equivalency Adjustments for Nephelometer-Based Particulate Matter Measurements of Emissions from Solid Biomass Fuel Use in Cookstoves

Science.gov (United States)

Soneja, Sutyajeet; Chen, Chen; Tielsch, James M.; Katz, Joanne; Zeger, Scott L.; Checkley, William; Curriero, Frank C.; Breysse, Patrick N.

2014-01-01

Great uncertainty exists around indoor biomass burning exposure-disease relationships due to lack of detailed exposure data in large health outcome studies. Passive nephelometers can be used to estimate high particulate matter (PM) concentrations during cooking in low resource environments. Since passive nephelometers do not have a collection filter they are not subject to sampler overload. Nephelometric concentration readings can be biased due to particle growth in high humid environments and differences in compositional and size dependent aerosol characteristics. This paper explores relative humidity (RH) and gravimetric equivalency adjustment approaches to be used for the pDR-1000 used to assess indoor PM concentrations for a cookstove intervention trial in Nepal. Three approaches to humidity adjustment performed equivalently (similar root mean squared error). For gravimetric conversion, the new linear regression equation with log-transformed variables performed better than the traditional linear equation. In addition, gravimetric conversion equations utilizing a spline or quadratic term were examined. We propose a humidity adjustment equation encompassing the entire RH range instead of adjusting for RH above an arbitrary 60% threshold. Furthermore, we propose new integrated RH and gravimetric conversion methods because they have one response variable (gravimetric PM2.5 concentration), do not contain an RH threshold, and is straightforward. PMID:24950062

Humidity and gravimetric equivalency adjustments for nephelometer-based particulate matter measurements of emissions from solid biomass fuel use in cookstoves.

Science.gov (United States)

Soneja, Sutyajeet; Chen, Chen; Tielsch, James M; Katz, Joanne; Zeger, Scott L; Checkley, William; Curriero, Frank C; Breysse, Patrick N

2014-06-19

Great uncertainty exists around indoor biomass burning exposure-disease relationships due to lack of detailed exposure data in large health outcome studies. Passive nephelometers can be used to estimate high particulate matter (PM) concentrations during cooking in low resource environments. Since passive nephelometers do not have a collection filter they are not subject to sampler overload. Nephelometric concentration readings can be biased due to particle growth in high humid environments and differences in compositional and size dependent aerosol characteristics. This paper explores relative humidity (RH) and gravimetric equivalency adjustment approaches to be used for the pDR-1000 used to assess indoor PM concentrations for a cookstove intervention trial in Nepal. Three approaches to humidity adjustment performed equivalently (similar root mean squared error). For gravimetric conversion, the new linear regression equation with log-transformed variables performed better than the traditional linear equation. In addition, gravimetric conversion equations utilizing a spline or quadratic term were examined. We propose a humidity adjustment equation encompassing the entire RH range instead of adjusting for RH above an arbitrary 60% threshold. Furthermore, we propose new integrated RH and gravimetric conversion methods because they have one response variable (gravimetric PM2.5 concentration), do not contain an RH threshold, and is straightforward.

Luminescent amine sensor based on europium(III) chelate.

Science.gov (United States)

Petrochenkova, Nataliya V; Mirochnik, Anatolii G; Emelina, Tatyana B; Sergeev, Alexander A; Leonov, Andrei A; Voznesenskii, Sergey S

2018-07-05

The effect of methylamine vapor on luminescence of Eu(III) tris-benzoylacetonate (I) immobilized in thin-layer chromatography plates has been investigated. It has been revealed that interaction of I with analyte vapor results in increase of the intensity of Eu(III) luminescence. The mechanism of the effect of methylamine vapors on intensification of the Eu(III) luminescence has been suggested using the data of IR spectroscopy and quantum chemistry calculations. The mechanism of luminescence sensitization consists in bonding of an analyte molecule with a water molecule into the coordination sphere of Eu(III). As a result, the bond of a water molecule with the luminescence centre weakens, rigid structural fragment including europium ion, water and methylamine molecules forms. The presence of such fragment must naturally promote decrease of influence of OH-vibrations on luminescence of the complex I. Copyright © 2018 Elsevier B.V. All rights reserved.

Visual estimation versus gravimetric measurement of postpartum blood loss: a prospective cohort study.

Science.gov (United States)

Al Kadri, Hanan M F; Al Anazi, Bedayah K; Tamim, Hani M

2011-06-01

One of the major problems in international literature is how to measure postpartum blood loss with accuracy. We aimed in this research to assess the accuracy of visual estimation of postpartum blood loss (by each of two main health-care providers) compared with the gravimetric calculation method. We carried out a prospective cohort study at King Abdulaziz Medical City, Riyadh, Saudi Arabia between 1 November 2009 and 31 December 2009. All women who were admitted to labor and delivery suite and delivered vaginally were included in the study. Postpartum blood loss was visually estimated by the attending physician and obstetrics nurse and then objectively calculated by a gravimetric machine. Comparison between the three methods of blood loss calculation was carried out. A total of 150 patients were included in this study. There was a significant difference between the gravimetric calculated blood loss and both health-care providers' estimation with a tendency to underestimate the loss by about 30%. The background and seniority of the assessing health-care provider did not affect the accuracy of the estimation. The corrected incidence of postpartum hemorrhage in Saudi Arabia was found to be 1.47%. Health-care providers tend to underestimate the volume of postpartum blood loss by about 30%. Training and continuous auditing of the diagnosis of postpartum hemorrhage is needed to avoid missing cases and thus preventing associated morbidity and mortality.

Silica nanoparticles with a substrate switchable luminescence

International Nuclear Information System (INIS)

Bochkova, O D; Mustafina, A R; Fedorenko, S V; Konovalov, A I

2011-01-01

Silica nanoparticles with visible (Tb and Ru doped), near IR (Yb doped) and dual visible-near IR luminescence (Ru-Yb doped) were obtained by reverse w/o microemulsion procedure. Plenty of luminescent complexes (from 4900 to 10000) encapsulated into each nanoparticle ensures the intensive luminescence of nanoparticles and their applicability as biomarkers. The silica surface decoration by definite anchor groups is the required step for the gaining to these nanoparticles marking and sensing functions. Thus covalent and non-covalent surface modification of these nanoparticles was developed to provide the binding with biotargets and sensing of anions. The dicationic surfactant coating of negatively charged Tb(III)-TCAS doped silica nanoparticles was chosen as the basis for the anion responsible system. The reversible insertion of the quenching anions (namely phenol red) into the surfactant based layer at the surface of luminescent nanoparticles switches off the Tb-centered luminescence. In turn the reversible reestablishment of the luminescence results from the competitive insertion of the non-quenching anions into the surfactant layer at the silica/water interface. The hydrophobic anions exemplified by dodecylsulfates versus hydrophilic ones (hydrophosphates) are preferable in the competition with phenol red anions.

Luminescence due to peptide linkage observed in L-cysteine molecules irradiated by infrared laser light

Energy Technology Data Exchange (ETDEWEB)

Tsujibayashi, Toru, E-mail: toru-t@cc.osaka-dent.ac.jp [Department of Physics, Osaka Dental University, 8-1 Kuzuha-hanazono, Hirakata, Osaka 573-1121 (Japan); Matsubara, Eiichi; Ichimiya, Masayoshi [Department of Physics, Osaka Dental University, 8-1 Kuzuha-hanazono, Hirakata, Osaka 573-1121 (Japan); Ohno, Nobuhito [Fundamental Electronics Research Institute, Osaka Electro-Communication University, 18-8 Hatsu-Cho, Neyagawa, Osaka 572-8530 (Japan)

2016-01-15

The sequence of amino acids in peptide chains consisting of proteins is the most fundamental information of living things. A direct and nondestructive method of reading is highly required as an alternative to the method based on the gene analysis. Luminescence detection is a very sensitive tool for investigating various materials. In order to find characteristic luminescence of each amino acid we study L-cysteine and L-tyrosine using UV laser of 3.36 eV with pulse duration of 1.5 ps. In addition to a common 2.66 eV band of the luminescence we have found 2.89 eV band for L-cysteine and 2.92 eV band for L-tyrosine. It can be interpreted that the side chain makes difference on the luminescence by affecting the peptide linkage or carbonyl group. - Highlights: • Luminescence from L-cysteine and L-tyrosine are studied. • Analyzing the luminescence enables to distinguish those two amino acids. • The lifetimes and the peak photon energies under UV laser excitation are presented.

Crustal thickness of Antarctica estimated using data from gravimetric satellites

Directory of Open Access Journals (Sweden)

M. Llubes

2018-04-01

Full Text Available Computing a better crustal thickness model is still a necessary improvement in Antarctica. In this remote continent where almost all the bedrock is covered by the ice sheet, seismic investigations do not reach a sufficient spatial resolution for geological and geophysical purposes. Here, we present a global map of Antarctic crustal thickness computed from space gravity observations. The DIR5 gravity field model, built from GOCE and GRACE gravimetric data, is inverted with the Parker–Oldenburg iterative algorithm. The BEDMAP products are used to estimate the gravity effect of the ice and the rocky surface. Our result is compared to crustal thickness calculated from seismological studies and the CRUST1.0 and AN1 models. Although the CRUST1.0 model shows a very good agreement with ours, its spatial resolution is larger than the one we obtain with gravimetric data. Finally, we compute a model in which the crust–mantle density contrast is adjusted to fit the Moho depth from the CRUST1.0 model. In East Antarctica, the resulting density contrast clearly shows higher values than in West Antarctica.

Quenching methods for background reduction in luminescence-based probe-target binding assays

Energy Technology Data Exchange (ETDEWEB)

Cai, Hong [Los Alamos, NM; Goodwin, Peter M [Los Alamos, NM; Keller, Richard A [Los Alamos, NM; Nolan, Rhiannon L [Santa Fe, NM

2007-04-10

Background luminescence is reduced from a solution containing unbound luminescent probes, each having a first molecule that attaches to a target molecule and having an attached luminescent moiety, and luminescent probe/target adducts. Quenching capture reagent molecules are formed that are capable of forming an adduct with the unbound luminescent probes and having an attached quencher material effective to quench luminescence of the luminescent moiety. The quencher material of the capture reagent molecules is added to a solution of the luminescent probe/target adducts and binds in a proximity to the luminescent moiety of the unbound luminescent probes to quench luminescence from the luminescent moiety when the luminescent moiety is exposed to exciting illumination. The quencher capture reagent does not bind to probe molecules that are bound to target molecules and the probe/target adduct emission is not quenched.

Dosimetry based on thermally and optically stimulated luminescence

International Nuclear Information System (INIS)

Agersnap Larsen, Niels

1999-01-01

Thermally Stimulated Luminescence (TL) and Optically Stimulated Luminescence (OSL) properties of quartz and α-Al 2 O 3 have been investigated. Anneling-induced OSL and TL sensitivity changes in quartz has been investigated by experiments and modelling. This study does not support a pre-dose effect to account for the observed annealing-induced sensitivity change. The experimental data indicates a more simple mechanism that involves alteration of the concentration of the defect centers. Results from modelling of removal or creation of defect centers comparing well with experimentally obtained data. Thermal quenching of luminescence for the main emission center, the F-center, in α-Al 2 O 3 :C has been investigated by analysing TL curves obtained at different heating rates. The thermal quenching dependence of luminescence is found to follow the classical Mott-Seitz expression. Basic investigations of OSL properties of αAl 2 O 3 :C, including: the thermal depth of the OSL traps, the temperature dependence of OSL, and the OSL stimulation spectra. Simultaneous measurements of TL and thermally stimulated conductivity (TSC) are presented for γ-irradiated αAl 2 O 3 :C. Activation energy analysis of the data reveals a superposition of several first-order TL and TSC peaks caused by release of charge carriers from a distribution of trapping states. Furthermore a description of an experimental method developed to determine the sign of the thermally released charge carriers has been presented. (au)

Uranyl(VI) luminescence spectroscopy at elevated temperatures

Energy Technology Data Exchange (ETDEWEB)

Steudtner, Robin; Franzen, Carola; Brendler, Vinzenz [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Div. Surface Processes; Haubitz, Toni [Brandenburg Univ. of Technology, Cottbus-Senftenberg (Germany)

2016-07-01

We studied the influence of temperature and ionic strength on the luminescence characteristics (band position, decay time and intensity) of the free uranyl ion (UO{sub 2}{sup 2+}) in acidic aqueous solution. Under the chosen conditions an increasing temperature reduced both intensity and luminescence decay time of the UO{sub 2}{sup 2+} luminescence, but the individual U(VI) emission bands did not change.

Sub-ppb level detection of uranium using ligand sensitized luminescence

International Nuclear Information System (INIS)

Kumar, Satendra; Maji, S.; Joseph, M.; Sankaran, K.

2015-01-01

Uranyl ion (UO 2 2+ ) is known to exhibit weak luminescence in aqueous medium due to poor molar absorptivity and low quantum yield. In order to enhance the luminescence of uranyl ion in aqueous medium, luminescence enhancing reagents such as H 3 PO 4 , H 2 SO 4 , HClO 4 have been widely used. Like lanthanides, uranyl luminescence can also be sensitized by using some organic ligands. Pyridine 2,6-dicarboxylic acid (PDA) has shown enhancement of luminescence of uranyl in aqueous medium. Enhancement in intensity is due to sensitization of uranyl luminescence by PDA. In order to see the effect of non-aqueous medium, in this work, luminescence of uranyl-PDA complex has been studied in acetonitrile medium. More than one order luminescence enhancement has been observed compared to UO 2 2+ - PDA complex in aqueous medium. The lifetime of uranyl luminescence of the complex in acetonitrile medium is 90 μs which is very high compared to 10 μs in aqueous medium, suggesting that the luminescence enhancement is a result of reduction in non-radiative decay channels in acetonitrile medium. The large enhancement of uranyl luminescence of uranyl-PDA complex in acetonitrile medium can be used for ultra-trace level detection of uranium. Linearity in the luminescence intensity has been observed over the uranium concentration range of 5 to 80 ppb and the detection limit calculated using the criterion of 3 σ is ~ 0.2 ppb. (author)

Comparison of neutron scattering, gravimetric and tensiometric methods for measuring soil water content in the field

International Nuclear Information System (INIS)

Jat, R.L.; Das, D.K.; Naskar, G.C.

1975-01-01

Water content of a sandy clay loam soil was measured by neutron scattering, gravimetric and tensiometric methods. Tensiometric measurement based on laboratory moisture retention curve gave comparatively higher moisture content than those obtained by other methods. No significant differences were observed among neutron meter, gravimetric and tensiometric measurement based on field calibration curve. Though for irrigation purposes all the methods can be used equally, use of tensiometric method with field calibration curve is suggested for easy and more accurate soil water content measurement where neutron meter is not available. (author)

Gravimetric Model of Quasigeoid in the Area of Slovakia

Directory of Open Access Journals (Sweden)

Juraj Papčo

2005-06-01

Full Text Available The gravimetric model of quasigeoid in the area of Slovakia was determined by using the revised and homogenised gravity mapping data in the scale of 1:25 000 from the area of Slovakia, and by using the mean Bouguer gravity anomalies with the resolution of 5´x7.5´ in the area 44°<φ<56° and 12°<λ<30° from abroad and by the digital terrain model DMR-2/ERTS89 with the resolution 3“ in the ellipsoidal latitude and 5“ in the ellipsoidal longitude from the area of Slovakia and the digital terrain model GTOPO30 with the resolution of 30“ in the ellipsoidal latitude and 30“ in the ellipsoidal longitude from abroad. The global part of the height anomaly was determined from the global geopotential model EGM96. The residual part of the height anomaly was determined by the Stokes integral formula. For the solution of the Stokes integra,l the Fast Fourier Transformation method in the spherical approximation was used. The gravimetric quasigeoid was tested by the GPS/levelling method using 46 points distributed on the area of Slovakia. The systematic trend of differences between height anomalies was rejected by the surface polynomial of second degree with 6 coefficients. The standard deviation after removing a systematic trend was 0.017 m

SrAl2O4:Eu2+ (1%) luminescence under UV, VUV and electron beam excitation

Science.gov (United States)

Nazarov, M.; Mammadova, S.; Spassky, D.; Vielhauer, S.; Abdullayeva, S.; Huseynov, A.; Jabbarov, R.

2018-01-01

This paper reports the luminescence properties of nanosized SrAl2O4:Eu2+ (1%) phosphors. The samples were prepared by combustion method at 600 °C, followed by annealing of the resultant combustion ash at 1000 °C in a reductive (Ar + H2) atmosphere. X-ray diffraction (XRD), photo luminescence (PL) and cathodoluminescence (CL) analysis and thermal stimulated luminescence (TSL) method were applied to characterize the phosphor. For the first time a peak at 375 nm was observed in CL spectra of SrAl2O4:Eu2+ (1%) nanophosphors. Luminescence excitation spectra analysis have shown that this peak is related to crystal defects. Also in TSL curve one strong peak was observed in the region above room temperature (T = 325 K), which is attributed to lattice defects, namely oxygen vacancies. A green LED was fabricated by the combination of the SrAl2O4:Eu2+ (1%) nanosized phosphor and a 365 nm UV InGaN chip.

Thermal treatment investigation of natural lizardite at the atmospheric pressure, based on XRD and differential thermal analysis/thermal gravimetric analysis methods

International Nuclear Information System (INIS)

Dabiri, R.; Karimi Shahraki, B.; Mollaei, H.; Ghaffari, M.

2009-01-01

Determination of stability limits, mineralogical changes and thermal reaction of serpentine minerals are very important for the investigation of magmatism, mechanism and depth of plates of subduction. During the subduction process, serpentine (Lizardite) minerals will release their water due to thermal reactions. This dehydration can play an important role in volcanism processes related to the subduction, In this study, serpentine minerals (Lizardite) collected from the Neyriz Ophiolite Complex were dehydrated under the constant atmospheric pressure. These mineralogical changes were determined by X-Ray diffraction and differential thermal analysis-thermal gravimetric analyses methods. This study shows natural lizardites that heated for about one hour is stable up to 550 d eg C . Dehydration reactions on lizardite started at approximately between 100 to 150 d eg C and dehydroxylation reactions started at approximately 550-690 d eg C . As a result of thermal reaction, the decomposition of lizardite will take place and then changes in to olivine (forsterite). Crystallization of olivine (forsterite) will start at 600 d eg C . This mineral is stable up to 700 d eg C and then crystallization of enstatite will start at 700 d eg C . During this dehydration and crystallization reaction, amorphous processes will start at 600 d eg C and some amount water and silica will release.

Apparatus for reducing solvent luminescence background emissions

Energy Technology Data Exchange (ETDEWEB)

Affleck, Rhett L. (Los Alamos, NM); Ambrose, W. Patrick (Los Alamos, NM); Demas, James N. (Charlottesville, VA); Goodwin, Peter M. (Jemez Springs, NM); Johnson, Mitchell E. (Pittsburgh, PA); Keller, Richard A. (Los Alamos, NM); Petty, Jeffrey T. (Los Alamos, NM); Schecker, Jay A. (Sante Fe, NM); Wu, Ming (Los Alamos, NM)

1998-01-01

The detectability of luminescent molecules in solution is enhanced by reducing the background luminescence due to impurity species also present in the solution. A light source that illuminates the solution acts to photolyze the impurities so that the impurities do not luminesce in the fluorescence band of the molecule of interest. Molecules of interest may be carried through the photolysis region in the solution or may be introduced into the solution after the photolysis region.

Optically stimulated luminescence (OSL) and some other luminescence images from granite slices exposed with radiations

International Nuclear Information System (INIS)

Hashimoto, T.; Notoya, S.; Ojima, T.; Hoteida, M.

1995-01-01

Optically stimulated luminescence (OSL) images of some X- and γ-irradiated granite slices were obtained using photon detection through a 570 nm bandpass filter with diode-laser excitation of 910 nm. Alternative photo-induced phosphorescence (PIP) images, which were colour photographed immediately after the sunlight exposure of slice samples, were also found to be helpful in the observation of the luminescence properties and to filter selection for OSL measurements. These OSL and PIP images were compared with some other colour luminescence images, including thermoluminescence images (TLCI) and after-glow images (AGCI). It was obvious that there exists a variety of coloured emissions derived mainly from feldspar constituents and these were found to be dependent on the geological history or metamorphism of the granites. (Author)

Structural features of the southern Tulum Fault System, western central Argentina, through gravimetric data and geomorphologic analyses

Science.gov (United States)

Rodríguez, Aixa I.; Christiansen, Rodolfo O.; Suvires, Graciela M.; Lince Klinger, Federico; Martinez, M. Patricia

2016-12-01

A gravimetric analysis over the Tulum Valley was made. This data was used to reveal the structural setting of the Tulum Fault System situated in the southeastern part of San Juan province in the arid western part of Argentina. This system is the boundary between two geological provinces, the eastern Precordillera Oriental and the Sierras Pampeanas Occidentales. Gravity data was processed using upward continuation and vertical derivative filters and all the results were compared with the geomorphological and the drainage systems maps of the area. Our assessment confirms the presence of two structures in the Pampeano basement with positive anomalies similar to those found in Valdivia and Barboza hills, two important depocenters with low gravimetric gradients separated by a zone with higher gravity anomalies than the depocenters to the east and west. In view of this, a structural map is proposed for the area. This system is important not only because it is the boundary between two geological provinces and has significance regarding regional tectonic issues but also because it controls the surface drainage, soils distribution and groundwater flow of the Tulum basin conditioning the land use distribution.

Precision gravimetric survey at the conditions of urban agglomerations

Science.gov (United States)

Sokolova, Tatiana; Lygin, Ivan; Fadeev, Alexander

2014-05-01

Large cities growth and aging lead to the irreversible negative changes of underground. The study of these changes at the urban area mainly based on the shallow methods of Geophysics, which extensive usage restricted by technogenic noise. Among others, precision gravimetry is allocated as method with good resistance to the urban noises. The main the objects of urban gravimetric survey are the soil decompaction, leaded to the rocks strength violation and the karst formation. Their gravity effects are too small, therefore investigation requires the modern high-precision equipment and special methods of measurements. The Gravimetry division of Lomonosov Moscow State University examin of modern precision gravimeters Scintrex CG-5 Autograv since 2006. The main performance characteristics of over 20 precision gravimeters were examined in various operational modes. Stationary mode. Long-term gravimetric measurements were carried at a base station. It shows that records obtained differ by high-frequency and mid-frequency (period 5 - 12 hours) components. The high-frequency component, determined as a standard deviation of measurement, characterizes the level of the system sensitivity to external noise and varies for different devices from 2 to 5-7 μGals. Midrange component, which closely meet to the rest of nonlinearity gravimeter drifts, is partially compensated by the equipment. This factor is very important in the case of gravimetric monitoring or observations, when midrange anomalies are the target ones. For the examined gravimeters, amplitudes' deviations, associated with this parameter may reach 10 μGals. Various transportation modes - were performed by walking (softest mode), lift (vertical overload), vehicle (horizontal overloads), boat (vertical plus horizontal overloads) and helicopter. The survey quality was compared by the variance of the measurement results and internal convergence of series. The measurement results variance (from ±2 to ±4 μGals) and its

Understanding of thermo-gravimetric analysis to calculate number of addends in multifunctional hemi-ortho ester derivatives of fullerenol

International Nuclear Information System (INIS)

Singh, Rachana; Goswami, Thakohari

2011-01-01

Test results for the applicability of existing thermo-gravimetric analysis (TGA) technique to ascertain average number of exohedral chemical attachment in a new class of fullerene dyads consisting of multiple hemi-ortho esters onto fullerenol is presented. Although the method is nicely applicable for higher fullerenol, but homogeneous phase products calculate lower number of addends, whereas, the hetero phase products indicate higher value. Lower value is attributed to either overlapping of thermal events or substituents effects and higher value is the contribution of tetra butyl ammonium hydroxide (TBAH) impurity used as phase transfer catalyst (PTC) in heterogeneous phase reactions. Presence of TBAH impurity is recognized through thermo-gravimetry mass spectrometry (TG-MS) measurement. Appropriate modification of test method to arrive at accurate and precise values of x (total mass contribution due to addends only) and y (total mass contribution due to fullerene plus char yield) are also reported. Successful use of two more different techniques, viz., electron-spray ionization mass spectrometry (ESI-MS) and X-ray photoelectron spectroscopy (XPS), supplement above results. Influences of fullerene and different substituents on thermal behavior of dyads are assessed.

Modern luminescence spectroscopy of minerals and materials

CERN Document Server

Gaft, Michael; Panczer, Gerard

2005-01-01

Luminescence Spectroscopy of Minerals and Materials presents an overview of the general concepts in luminescence spectroscopy as well as experimental methods and their interpretation. Special emphasis is laid on the fluorescence lifetime and the determination of time-resolved spectra. This method enables the exposure of new luminescence in minerals previously hidden by more intensive centers. Specialists in the fields of solid state physics, chemistry and spectroscopy will find a wealth of new information in this unique book.

Identifying drought response of semi-arid aeolian systems using near-surface luminescence profiles and changepoint analysis, Nebraska Sandhills.

Science.gov (United States)

Buckland, Catherine; Bailey, Richard; Thomas, David

2017-04-01

Two billion people living in drylands are affected by land degradation. Sediment erosion by wind and water removes fertile soil and destabilises landscapes. Vegetation disturbance is a key driver of dryland erosion caused by both natural and human forcings: drought, fire, land use, grazing pressure. A quantified understanding of vegetation cover sensitivities and resultant surface change to forcing factors is needed if the vegetation and landscape response to future climate change and human pressure are to be better predicted. Using quartz luminescence dating and statistical changepoint analysis (Killick & Eckley, 2014) this study demonstrates the ability to identify step-changes in depositional age of near-surface sediments. Lx/Tx luminescence profiles coupled with statistical analysis show the use of near-surface sediments in providing a high-resolution record of recent system response and aeolian system thresholds. This research determines how the environment has recorded and retained sedimentary evidence of drought response and land use disturbances over the last two hundred years across both individual landforms and the wider Nebraska Sandhills. Identifying surface deposition and comparing with records of climate, fire and land use changes allows us to assess the sensitivity and stability of the surface sediment to a range of forcing factors. Killick, R and Eckley, IA. (2014) "changepoint: An R Package for Changepoint Analysis." Journal of Statistical Software, (58) 1-19.

Luminescence enhancement in irradiated polyethylene

International Nuclear Information System (INIS)

Charlesby, A.; Owen, G.P.

1976-01-01

Results are presented for the luminescence decay in polyethylene following irradiation at liquid nitrogen temperature and its enhancement on application of an electric field. It is found that both the luminescence enhancement and its subsequent decay may be described by a model involving electron tunnelling from a monoenergetic trap distribution to the parent positive ion. The possible nature of the trap is briefly discussed. (author)

Dosimetry based on thermally and optically stimulated luminescence

Energy Technology Data Exchange (ETDEWEB)

Agersnap Larsen, Niels

1999-01-01

Thermally Stimulated Luminescence (TL) and Optically Stimulated Luminescence (OSL) properties of quartz and {alpha}-Al{sub 2}O{sub 3} have been investigated. Anneling-induced OSL and TL sensitivity changes in quartz has been investigated by experiments and modelling. This study does not support a pre-dose effect to account for the observed annealing-induced sensitivity change. The experimental data indicates a more simple mechanism that involves alteration of the concentration of the defect centers. Results from modelling of removal or creation of defect centers comparing well with experimentally obtained data. Thermal quenching of luminescence for the main emission center, the F-center, in {alpha}-Al{sub 2}O{sub 3}:C has been investigated by analysing TL curves obtained at different heating rates. The thermal quenching dependence of luminescence is found to follow the classical Mott-Seitz expression. Basic investigations of OSL properties of {alpha}Al{sub 2}O{sub 3}:C, including: the thermal depth of the OSL traps, the temperature dependence of OSL, and the OSL stimulation spectra. Simultaneous measurements of TL and thermally stimulated conductivity (TSC) are presented for {gamma}-irradiated {alpha}Al{sub 2}O{sub 3}:C. Activation energy analysis of the data reveals a superposition of several first-order TL and TSC peaks caused by release of charge carriers from a distribution of trapping states. Furthermore a description of an experimental method developed to determine the sign of the thermally released charge carriers has been presented. (au) 8 tabs., 59 ills., 90 refs.

Luminescence properties of the Sm-doped borate glasses

International Nuclear Information System (INIS)

Kindrat, I.I.; Padlyak, B.V.; Drzewiecki, A.

2015-01-01

The optical absorption and photoluminescence (emission and excitation) spectra as well as decay kinetics of a series of the Sm-doped glasses with Li 2 B 4 O 7 , LiKB 4 O 7 , CaB 4 O 7 , and LiCaBO 3 compositions were investigated and analysed. The Li 2 B 4 O 7 :Sm, LiKB 4 O 7 :Sm, CaB 4 O 7 :Sm, and LiCaBO 3 :Sm glasses of high optical quality have been obtained from the corresponding polycrystalline compounds in the air atmosphere, using a standard glass technology. On the basis of electron paramagnetic resonance (EPR) and optical spectra analysis it was shown that the samarium impurity is incorporated into the glass network as Sm 3+ (4f 5 , 6 H 5/2 ) ions, exclusively. All observed 4f – 4f transitions of the Sm 3+ centres in the optical absorption and luminescence spectra of the investigated glasses are identified. Most intense emission band of the Sm 3+ ions peaked about 598 nm ( 4 G 5/2 → 6 H 7/2 transition) is characterised by a single exponential decay with typical lifetime values, which depend on the basic glass composition as well as concentration and local structure of the Sm 3+ luminescence centres. The quantum efficiency has been evaluated for observed transitions of the Sm 3+ centres using obtained experimental lifetimes and radiative lifetimes calculated by Judd–Ofelt theory. The calculated high quantum efficiencies and measured quantum yields of luminescence show that the investigated borate glasses are perspective luminescence materials. Energy transfer from the Ce 3+ non-controlled impurity and intrinsic luminescence centres to the Sm 3+ centres has been observed. Peculiarities of the Sm 3+ local structure in the network of investigated glasses have been discussed based on the obtained spectroscopic results and structural data. - Highlights: • The Sm-doped Li 2 B 4 O 7 , LiKB 4 O 7 , CaB 4 O 7 , and LiCaBO 3 glasses of high quality were obtained. • EPR, optical absorption and luminescence spectra of Sm 3+ ions in obtained glasses were

Study of Polymeric Luminescent Blend (PC/PMMA) Doped with Europium Complex under Gamma-Iradiation

International Nuclear Information System (INIS)

Parra, D. F.

2006-01-01

Spectroscopic properties of blends formed by bisphenol-A polycarbonate (PC) and poly(methyl methacrylate) (PMMA) doped with europium in organic complex were studied. Polymeric luminescent blends are potential materials for many applications; however, little information has been reported concerning the stability under thermal and radiation conditions. Luminescent films were synthesized from europium thenoyltrifluoroacetonate at different concentrations doped in PC/PMMA blends. Films produced of the luminescent polymer blend were irradiated in a 60 C o source. Their luminescent properties, in the solid state, as well as, the thermal oxidative resistance after gamma irradiation was investigated. These systems were characterized by elemental analysis, thermogravimetry (TGA), differential scanning calorimetry (DSC) and infrared spectroscopy (FTIR). Based on TGA data, the thermal stability of PC/PMMA:(tta)3 system is higher than the polymer blend. The DSC results indicated that those new systems are chemically stables. The emission spectra of the Eu 3 +-tta complex doped in the PC/PMMA recorded at 298 and 77 K exhibited the characteristic bands arising from the 5 D 0 →7 F J transitions (J = 0-6). The luminescence intensity decreases with increasing of precursor concentration in the doped polymer obtained by chemical reaction. This result is different from that of samples obtained by physical method in melting doping. The blend was irradiated under ionizing radiation of 60 C o source. After irradiation of the luminescent films the physical properties of luminescence, thermal and oxidative stability were evaluated.(Fapesp and Cnpq financial support)

Study of the corrosion behavior of magnesium alloy weddings in NaCl solutions by gravimetric tests

Energy Technology Data Exchange (ETDEWEB)

Segarra, J. A.; Calderon, B.; Portoles, A.

2015-07-01

In this article, the corrosion behavior of commercial AZ31 welded plates in aqueous chloride media was investigated by means of gravimetric techniques and Neutral Salt Spray tests (NSS). The AZ31 samples tested were welded using Gas Tugsten Arc Welding (GTAW) and different filler materials. Material microstructures were investigated by optical microscopy to stablish the influence of those microstructures in the corrosion behavior. Gravimetric and NSS tests indicate that the use of more noble filler alloys for the sample welding, preventing the reduction of aluminum content in weld beads, does not imply a better corrosion behavior. (Author)

Photoluminescence, reddish orange long persistent luminescence and photostimulated luminescence properties of praseodymium doped CdGeO3 phosphor

International Nuclear Information System (INIS)

Jin, Yahong; Hu, Yihua; Chen, Li; Fu, Yinrong; Mu, Zhongfei; Wang, Tao; Lin, Jun

2014-01-01

Highlights: • A novel phosphor CdGeO 3 :Pr 3+ was synthesized successfully. • The persistent luminescence properties of CdGeO 3 :Pr 3+ were studied. • The photostimulated luminescence properties of CdGeO 3 :Pr 3+ were investigated. • The persistent and photostimulated luminescence mechanisms were discussed in detail. - Abstract: Praseodymium doped CdGeO 3 phosphors were prepared successfully by a conventional high temperature solid-state reaction method. It showed reddish orange long persistent luminescence (LPL) after the short UV-irradiation. The reddish orange photostimulated luminescence (PSL) was also observed upon near infrared stimulation at 980 nm after per-exposure into UV light. The origin of LPL and PSL was identified with the emission from Pr 3+ ions with the aid of traps in host lattice. The optimal concentration of Pr 3+ ions for the brightest photoluminescence (PL) emission and the best LPL characteristic were experimentally to be about 3% and 0.5 mol%, respectively. The trapping and de-trapping processes of charge carriers between shallower and deep traps were illustrated. A model was proposed on the basis of experimental results to study the mechanisms of LPL and PSL

A detailed gravimetric geoid of North America, the North Atlantic, Eurasia, and Australia

Science.gov (United States)

Marsh, J. G.

1973-01-01

A computer program was developed for the calculation of a goid based upon a combination of satellite and surface gravity data. A detailed gravimetric geoid of North America, the North Atlantic, Eurasia, and Australia was derived by using this program.

Comparison of the gravimetric, phenol red, and 14C-PEG-3350 methods to determine water absorption in the rat single-pass intestinal perfusion model.

Science.gov (United States)

Sutton, S C; Rinaldi, M T; Vukovinsky, K E

2001-01-01

This study was undertaken to determine whether the gravimetric method provided an accurate measure of water flux correction and to compare the gravimetric method with methods that employ nonabsorbed markers (eg, phenol red and 14C-PEG-3350). Phenol red,14C-PEG-3350, and 4-[2-[[2-(6-amino-3-pyridinyl)-2-hydroxyethyl]amino]ethoxy]-, methyl ester, (R)-benzene acetic acid (Compound I) were co-perfused in situ through the jejunum of 9 anesthetized rats (single-pass intestinal perfusion [SPIP]). Water absorption was determined from the phenol red,14C-PEG-3350, and gravimetric methods. The absorption rate constant (ka) for Compound I was calculated. Both phenol red and 14C-PEG-3350 were appreciably absorbed, underestimating the extent of water flux in the SPIP model. The average +/- SD water flux microg/h/cm) for the 3 methods were 68.9 +/- 28.2 (gravimetric), 26.8 +/- 49.2 (phenol red), and 34.9 +/- 21.9 (14C-PEG-3350). The (average +/- SD) ka for Compound I (uncorrected for water flux) was 0.024 +/- 0.005 min(-1). For the corrected, gravimetric method, the average +/- SD was 0.031 +/- 0.001 min(-1). The gravimetric method for correcting water flux was as accurate as the 2 "nonabsorbed" marker methods.

Cleavage Luminescence from Cleaved Indium Phosphide

International Nuclear Information System (INIS)

Dong-Guang, Li

2008-01-01

We outline the experiments performed to gain further information about the structure and properties of cleaved InP surfaces. The experiments involved detecting the luminescence produced after cleaving thin InP plates within a high vacuum, by a process of converting the luminescence to an electrical signal which could be amplified and measured accurately. The experimental results show that the detected luminescence durations from cleaved InP are usually only about 10μs. It is believed that this time represents the time of travel of the crack with the actual recombination time being much shorter. Strong signals could also be picked up from cleaved InP in air

Luminescent converter of neodymium laser radiation

International Nuclear Information System (INIS)

Ryba-Romanowski, W.; Golab, S.

1992-01-01

The new luminescent converter of neodymium laser radiation has been worked out. Activated inorganic compounds of ytterbium and erbium ions has been used as luminescent agent. The multi-component inorganic glass containing tellurium oxide as well as boron, sodium, magnesium and zinc oxides has been applied as a converter matrix

Gravimetric method for in vitro calibration of skin hydration measurements.

Science.gov (United States)

Martinsen, Ørjan G; Grimnes, Sverre; Nilsen, Jon K; Tronstad, Christian; Jang, Wooyoung; Kim, Hongsig; Shin, Kunsoo; Naderi, Majid; Thielmann, Frank

2008-02-01

A novel method for in vitro calibration of skin hydration measurements is presented. The method combines gravimetric and electrical measurements and reveals an exponential dependency of measured electrical susceptance to absolute water content in the epidermal stratum corneum. The results also show that absorption of water into the stratum corneum exhibits three different phases with significant differences in absorption time constant. These phases probably correspond to bound, loosely bound, and bulk water.

Separation and gravimetric determination of rare earths with N-(3-nitrobenzoyl), N-(3-tolyl) hydroxylamine

International Nuclear Information System (INIS)

Agrawal, Y.K.; Kapoor, H.L.

1977-01-01

The N-(3-nitrobenzoyl), N-(3-tolyl) hydroxylamine is used as a reagent for the separation and gravimetric determination of Ce 3+ , La 3+ , Pr 3+ , Nd 3+ , Sm 3+ and Gd 3+ . The optimum conditions of precipitation of these rare earths indicate that, by control of pH and judicious use of masking agents, these ions can be separated from, and determined gravimetrically among several other ions. Further, the stochiometric nature of the N-(3-nitrobenzoyl), N-(3-tolyl) hydroxylamine acid is advantageous for the direct determination by weighting of (C 14 H 11 N 2 O 4 ) 3 M complex without ignition to obtain oxides. These complexes are characterized by infrared spectra

Luminescence spectroscopy with synchrotron radiation: History, highlights, future

International Nuclear Information System (INIS)

Zimmerer, Georg

2006-01-01

Luminescence spectroscopy and the investigation of dynamical processes with synchrotron radiation (SR) started about 35 years ago in nearly all SR laboratories existing at that time. In the present paper, the pioneering experiments are particularly emphasized. The exciting development is illustrated presenting highlights for the whole period from the beginning to the present day. The highlights are taken from fields like exciton self-trapping, inelastic electron-electron scattering, optically stimulated desorption, cross luminescence, or probing of cluster properties with luminescence spectroscopic methods. More technological aspects play a role in present day's experiments, like quantum cutting in rare-earth-doped insulators. Promising two-photon excitation and light amplification experiments with SR will be included, as well as the first results obtained in a luminescence experiment with selective Vaccum ultraviolet-free electron laser excitation. Finally, a few ideas concerning the future development of luminescence spectroscopy with SR will be sketched

Gravimetric determination of cadmium with o-phenanthroline and iodide

International Nuclear Information System (INIS)

Yoshida, Hitoshi; Mizuno, Kazunori; Taga, Mitsuhiko; Hikime, Seiichiro

1976-01-01

Cadmium forms insoluble mixed ligand complex with o-phenanthroline and iodide ions. By using the complex a new gravimetric method for the determination of cadmium was investigated. The recommended analytical procedure is as follows: Adjust pH value of a solution containing 5 to 45 mg cadmium to 4 with 3 M acetic acid-sodium acetate buffer solution. Add over threefold moles of potassium iodide to the solution and heat to just before boiling. To the solution add 0.1% ascorbic acid solution and then 0.1 M o-phenanthroline solution drop by drop in excess with stirring, and cool the mixture to room temperature. Filter the precipitates and wash first with 0.01% potassium iodide solution and then with water. Dry the precipitates at 110 0 C for two hours and weigh as Cd(o-phen) 2 I 2 (I). The gravimetric factor of the complex for cadmium is 0.1547. Chemical composition of the precipitate is variable when o-phenanthroline is added less than twofold moles to cadmium. Adding the o-phenanthroline solution 2.4-fold moles against cadmium, the ternary complex (I) precipitates quantitatively. Though a large excess of iodide ion in the solution contaminated the precipitate, the contamination was avoided when precipitation was carryed out at high temperature and in the presence of ascorbic acid. By the presented procedure 5 to 45 mg of cadmium are determined with a standard deviation of 0 C. (JPN)

Chemisorptive luminescence on γ-irradiated magnesium oxide

International Nuclear Information System (INIS)

Breakspere, R.J.; Read, R.L.

1976-01-01

The intensity of a chemisorptive luminescence produced on MgO by oxygen at room temperature is increased by prior γ-irradiation of the MgO, under vacuum, before adsorption. This enhancement of the luminescence increases with radiation dose up to 1.9 x 10 6 rad and is attributed to the interaction between the F + sub (s) centres produced by the radiation and oxygen molecules arriving at the surface from the gas phase. In this work, the spectrum of the emitted luminescence could not be measured. (author)

Europium enabled luminescent nanoparticles for biomedical applications

Energy Technology Data Exchange (ETDEWEB)

Syamchand, S.S., E-mail: syamchand.ss@gmail.com; Sony, G., E-mail: emailtosony@gmail.com

2015-09-15

Lanthanide based nanoparticles are receiving great attention ought to their excellent luminescent and magnetic properties and find challenging biomedical applications. Among the luminescent lanthanide NPs, europium based NPs (Eu-NPs) are better candidates for immunoassay and imaging applications. The Eu-NPs have an edge over quantum dots (QDs) by means of their stable luminescence, long fluorescence lifetime, sharp emission peaks with narrow band width, lack of blinking and biocompatibility. This review surveys the synthesis and properties of a variety of Eu-NPs consolidated from different research articles, for their applications in medicine and biology. The exquisite luminescent properties of Eu-NPs are explored for developing biomedical applications such as immunoassay and bioimaging including multimodal imaging. The biomedical applications of Eu-NPs are mostly diagnostic in nature and mainly focus on various key analytes present in biological systems. The luminescent properties of europium enabled NPs are influenced by a number of factors such as the site symmetry, the metal nanoparticles, metal ions, quantum dots, surfactants, morphology of Eu-NPs, crystal defect, phenomena like antenna effect and physical parameters like temperature. Through this review we explore and assimilate all the factors which affect the luminescence in Eu-NPs and coil a new thread of parameters that control the luminescence in Eu-NPs, which would provide further insight in developing Eu-based nanoprobes for future biomedical prospects. - Highlights: • The review describes 14 major factors that influence the luminescence properties of europium enabled luminescent nanoparticles (Eu-NPs). • Surveys different types of europium containing nanoparticles that have been reported for their biomedical applications. • Eu-NPs are conveniently divided into four different categories, based on the type of the substrates involved. The four categories are (1) virgin Eu-substrate based NPs; (2

Europium enabled luminescent nanoparticles for biomedical applications

International Nuclear Information System (INIS)

Syamchand, S.S.; Sony, G.

2015-01-01

Lanthanide based nanoparticles are receiving great attention ought to their excellent luminescent and magnetic properties and find challenging biomedical applications. Among the luminescent lanthanide NPs, europium based NPs (Eu-NPs) are better candidates for immunoassay and imaging applications. The Eu-NPs have an edge over quantum dots (QDs) by means of their stable luminescence, long fluorescence lifetime, sharp emission peaks with narrow band width, lack of blinking and biocompatibility. This review surveys the synthesis and properties of a variety of Eu-NPs consolidated from different research articles, for their applications in medicine and biology. The exquisite luminescent properties of Eu-NPs are explored for developing biomedical applications such as immunoassay and bioimaging including multimodal imaging. The biomedical applications of Eu-NPs are mostly diagnostic in nature and mainly focus on various key analytes present in biological systems. The luminescent properties of europium enabled NPs are influenced by a number of factors such as the site symmetry, the metal nanoparticles, metal ions, quantum dots, surfactants, morphology of Eu-NPs, crystal defect, phenomena like antenna effect and physical parameters like temperature. Through this review we explore and assimilate all the factors which affect the luminescence in Eu-NPs and coil a new thread of parameters that control the luminescence in Eu-NPs, which would provide further insight in developing Eu-based nanoprobes for future biomedical prospects. - Highlights: • The review describes 14 major factors that influence the luminescence properties of europium enabled luminescent nanoparticles (Eu-NPs). • Surveys different types of europium containing nanoparticles that have been reported for their biomedical applications. • Eu-NPs are conveniently divided into four different categories, based on the type of the substrates involved. The four categories are (1) virgin Eu-substrate based NPs; (2

luminescence properties

Indian Academy of Sciences (India)

1Faculty of Science and Arts, Department of Chemistry, Bozok University, Yozgat 66900, Turkey. 2Faculty of Science, Department of Chemistry, Erciyes ... synthesized by the conventional solid-state reaction method, their crystal structures and luminescence properties were investigated. X-ray diffraction patterns (XRD) ...

Identifying well-bleached quartz using the different bleaching rates of quartz and feldspar luminescence signals

DEFF Research Database (Denmark)

Murray, A.S.; Thomsen, Kristina Jørkov; Masuda, N.

2012-01-01

When dating older sedimentary deposits using quartz, there are no unambiguous methods for identifying the presence of incomplete bleaching. Current statistical analysis of dose distributions depends entirely on the assumption that incomplete bleaching and mixing are the main causes of any excess...... dispersion in the distribution; the only existing way to test this assumption is using independent age control. Here we suggest a new approach to this question, based on the differential bleaching rates of quartz and feldspar luminescence signals. We first present data that confirm the differences...... in relative bleaching rates of quartz optically stimulated luminescence (OSL) and feldspar luminescence stimulated at 50 °C by infrared light (IR50) and feldspar luminescence stimulated at 290 °C by infrared light after a stimulation at 50 °C (pIRIR290), and use recently deposited samples to determine...

Luminescent properties of fluorophosphate glasses with lead chalcogenides molecular clusters

International Nuclear Information System (INIS)

Kolobkova, E.V.; Kukushkin, D.S.; Nikonorov, N.V.; Shakhverdov, T.A.; Sidorov, A.I.; Vasiliev, V.N.

2015-01-01

Fluorophosphate glasses containing lead, selenium, and sulfur exhibit an intense luminescence in the 400–620 nm spectral region when excited by the 240–420 nm radiation. This luminescence is due to the presence of (PbSe) n and/or (PbS) n molecular clusters in the glasses, which appear in the as-prepared glasses before quantum dots formation. The thermal treatment at temperatures less than the glass transition temperature results in the red-shift of the luminescence bands and in an increase in the luminescence intensity. Heating the thermally treated glass samples leads to the reversible thermal quenching of the luminescence. - Highlights: • Fluorophosphate glasses with Pb, Se, and S ions contain (PbSe) n or (PbS) n molecular clusters. • (PbSe) n and (PbS) n molecular clusters possess luminescence in the visible with UV excitation. • Heating the glass leads to the reversible thermal quenching of the luminescence

Luminescent polymethyl methacrylate modified by gamma radiation

International Nuclear Information System (INIS)

Morais, Guilherme F.; Forster, Pedro L.; Marchini, Leonardo G.; Lugao, Ademar B.; Parra, Duclerc F.

2011-01-01

Thin films of PMMA (polymethyl methacrylate) doped with luminescent complexes have been studied and developed for applications in advanced technologies. The problem of stability of these films is focused in this study. Films stabilization by reaction with fluorinated monomers is a recent study that aims to increase its luminescence properties for long time. The films were prepared by dilution of PMMA in chloroform with addition of europium complex, at proportion of 5% by weight of polymer. The luminescent polymer films were obtained by casting. Thin layer slides of the film were separated in three parts. One was reacted with fluorinated monomers (C 2 F 4 ) in closed reactor for 48 hours. A second part was reacted with C 2 F 4 after irradiation in gamma source at 5 kGy in simultaneous process. The last part was used as obtained. The luminescent polymer matrices were characterized using the techniques of infrared (FTIR) and thermogravimetry (TGA/DTG). Samples of the films were, in presence of fluorine monomers, exposed to ionizing radiation in dose of 5 kGy, for react with monomers in the doped polymer surface. In this case the effects of radiation were evaluated on the luminescent films. (author)

Zero-reabsorption doped-nanocrystal luminescent solar concentrators.

Science.gov (United States)

Erickson, Christian S; Bradshaw, Liam R; McDowall, Stephen; Gilbertson, John D; Gamelin, Daniel R; Patrick, David L

2014-04-22

Optical concentration can lower the cost of solar energy conversion by reducing photovoltaic cell area and increasing photovoltaic efficiency. Luminescent solar concentrators offer an attractive approach to combined spectral and spatial concentration of both specular and diffuse light without tracking, but they have been plagued by luminophore self-absorption losses when employed on practical size scales. Here, we introduce doped semiconductor nanocrystals as a new class of phosphors for use in luminescent solar concentrators. In proof-of-concept experiments, visibly transparent, ultraviolet-selective luminescent solar concentrators have been prepared using colloidal Mn(2+)-doped ZnSe nanocrystals that show no luminescence reabsorption. Optical quantum efficiencies of 37% are measured, yielding a maximum projected energy concentration of ∼6× and flux gain for a-Si photovoltaics of 15.6 in the large-area limit, for the first time bounded not by luminophore self-absorption but by the transparency of the waveguide itself. Future directions in the use of colloidal doped nanocrystals as robust, processable spectrum-shifting phosphors for luminescent solar concentration on the large scales required for practical application of this technology are discussed.

Synthesis and luminescent properties of a novel green-emitting Tb (Ⅲ) complex based on amino-modified fluorine silicone oil and isophorone diisocyanate

Science.gov (United States)

Hao, Haixia; Chu, Yang; Yu, Zhenjiang; Xie, Hongde; Seo, Hyo Jin

2017-10-01

The novel luminescent polymer-rare earth complexes, denoted as (PFSi-IPDI)-Tb(Ⅲ)-Phen, have been successfully synthesized and can be made into flexible films. Amino-modified fluorine silicone oil-isophorone diisocyanate (PFSi-IPDI) was used as the host macromolecular ligand, and 1, 10-Phenanthroline (Phen) as the secondary small-molecular co-ligand. The luminescent lanthanide complexes were characterized by fourier transform infrared (FITR), scanning electron microscope (SEM), thermogravimetric analysis (TGA). The luminescent properties were investigated through photoluminescence excitation (PLE) and emission (PL) spectroscopy. FTIR analysis verifies the successful preparation and integration of PFSi-IPDI to Tb3+. The comparatively uniform morphological structure can be observed in the images of SEM. The polymer-rare earth complexes display the typical luminescence emission peaks under the excitation wavelength of 330 nm. From the decay curve, the short lifetime (about 0.89 ms) is observed for (PFSi-IPDI)-Tb(Ⅲ)-Phen (0.6 mol/L). Moreover, these luminescent polymer-rare earth complexes possess superior thermal stability (T5 > 195 °C). All the interesting results suggest the potential application of the luminescent polymer-rare earth complexes in green-emitting luminescent materials under high temperature.

Intrinsic luminescence of un-doped borate glasses

International Nuclear Information System (INIS)

Kindrat, I.I.; Padlyak, B.V.; Drzewiecki, A.

2017-01-01

The nature of intrinsic luminescence in the un-doped borate glasses of different compositions has been investigated using spectroscopic methods including photoluminescence, optical absorption, electron paramagnetic resonance (EPR), and thermally stimulated luminescence (TSL). The un-doped borate glasses with Li 2 B 4 O 7 , LiKB 4 O 7 , CaB 4 O 7 , and LiCaBO 3 basic compositions were obtained from corresponding polycrystalline compounds in the air with usage the standard technology of glasses. Three different broad emission bands in the UV–Visible spectral range have been observed under different wavelength of photoexcitation. The luminescence kinetics of the observed emission bands have been registered and analysed. The nature and possible mechanisms of the intrinsic luminescence in the investigated borate glasses are considered and discussed based on the obtained results and referenced data.

Oxide/polymer nanocomposites as new luminescent materials

Science.gov (United States)

Vollath, D.; Szabó, D. V.; Schlabach, S.

2004-06-01

It is demonstrated that nanocomposites, consisting of an electrically insulating oxide core and PMMA coating exhibit strong luminescence. This luminescence is connected to the interface, where PMMA is bond via a carboxylate bonding to the surface. In this case, luminescence is originated at the carbonyl group of the coating polymer. With decreasing particle size, this emission shows a blue shift, following a law inversely the ones found for quantum confinement systems. For semi-conducting oxides, such as ZnO, this interface related emission is found additionally to quantum confinement phenomena.

Application of luminescence techniques in retrospective dosimetry

DEFF Research Database (Denmark)

Bøtter-Jensen, L.; Jungner, H.

1999-01-01

Luminescence signals measured from minerals within bricks or ceramic samples can provide information about the absorbed radiation dose. This feature has for several years been used in dating archaeological and geological samples and recently luminescence techniques have been intensively used far ...

Raman and luminescence spectroscopy of zirconium oxide with the use of the MOLE microprobe

International Nuclear Information System (INIS)

Doyle, T.E.; Alvarez, J.L.

1984-01-01

Raman and luminescence spectroscopy with the use of the MOLE microprobe has been used to characterize ZrO 2 originating from oxidized fuel-rod cladding in nuclear accidents. Micro-Raman analysis of samples from Three Mile Island Unit 2 and the Power Burst Facility identified tetragonal and cubic ZrO 2 . The tetragonal and cubic phases are high-temperature polymorphs of ZrO 2 and provide information about temperatures and hydrogen formation in the TMI-2 core. The data suggest that the tetragonal ZrO 2 in TMI-2 samples was stabilized by a crystallite size effect, whereas cubic ZrO 2 in PBF debris samples was stabilized by impurities. Luminescence was used to differentiate yttria-stabilized ZrO 2 ceramics and oxidized fuel-rod cladding in PBF debris samples. The ZrO 2 ceramics produced strong, sharp luminescence peaks which indicated the presence of titanium and yttria in the ZrO 2 . Oxidized fuel-rod cladding displayed no luminescence

Luminescence at the end of the tunnelling - Investigating charge transfer mechanisms and luminescence dating methods for feldspar minerals

NARCIS (Netherlands)

Kars, R.H.

2014-01-01

This thesis comprises analyses of mineral physics with an application in geology and archeology. The thesis contributes to the development of feldspar luminescence dating methods in order to extend the applicable age range of feldspar luminescence dating in the Quaternary (last 2.6 Ma). The research

A highly accurate absolute gravimetric network for Albania, Kosovo and Montenegro

Science.gov (United States)

Ullrich, Christian; Ruess, Diethard; Butta, Hubert; Qirko, Kristaq; Pavicevic, Bozidar; Murat, Meha

2016-04-01

The objective of this project is to establish a basic gravity network in Albania, Kosovo and Montenegro to enable further investigations in geodetic and geophysical issues. Therefore the first time in history absolute gravity measurements were performed in these countries. The Norwegian mapping authority Kartverket is assisting the national mapping authorities in Kosovo (KCA) (Kosovo Cadastral Agency - Agjencia Kadastrale e Kosovës), Albania (ASIG) (Autoriteti Shtetëror i Informacionit Gjeohapësinor) and in Montenegro (REA) (Real Estate Administration of Montenegro - Uprava za nekretnine Crne Gore) in improving the geodetic frameworks. The gravity measurements are funded by Kartverket. The absolute gravimetric measurements were performed from BEV (Federal Office of Metrology and Surveying) with the absolute gravimeter FG5-242. As a national metrology institute (NMI) the Metrology Service of the BEV maintains the national standards for the realisation of the legal units of measurement and ensures their international equivalence and recognition. Laser and clock of the absolute gravimeter were calibrated before and after the measurements. The absolute gravimetric survey was carried out from September to October 2015. Finally all 8 scheduled stations were successfully measured: there are three stations located in Montenegro, two stations in Kosovo and three stations in Albania. The stations are distributed over the countries to establish a gravity network for each country. The vertical gradients were measured at all 8 stations with the relative gravimeter Scintrex CG5. The high class quality of some absolute gravity stations can be used for gravity monitoring activities in future. The measurement uncertainties of the absolute gravity measurements range around 2.5 micro Gal at all stations (1 microgal = 10-8 m/s2). In Montenegro the large gravity difference of 200 MilliGal between station Zabljak and Podgorica can be even used for calibration of relative gravimeters

Analysis of thermal treatment effects upon optico-luminescent and scintillation characteristics of oxide and chalcogenide crystals

International Nuclear Information System (INIS)

Ryzhikov, Vladimir D.; Grinyov, Boris V.; Pirogov, Evgeniy N.; Galkin, Sergey N.; Nagornaya, Lyudmila L.; Bondar, Vladimir G.; Babiychuk, Inna P.; Krivoshein, Vadim I.; Silin, Vitaliy I.; Lalayants, Alexandr I.; Voronkin, Evgeniy F.; Katrunov, Konstantin A.; Onishchenko, Gennadiy M.; Vostretsov, Yuriy Ya.; Malyi, Pavel Yu.; Lisetskaya, Elena K.; Lisetskii, Longin N.

2005-01-01

This work has been aimed at analyzing the effects of various thermal treatment factors upon optical-luminescent, scintillation and other functional characteristics of complex oxide and chalcogenide crystals. The crystals considered in this work are scintillators with intrinsic (PWO, CWO, BGO), activator (GSO:Ce) or complex-defect ZnSe(Te) type of luminescence. Important factors of thermal treatment are not only the temperature and its variation with time, but also the chemical composition of the annealing medium, its oxidation-reduction properties

Luminescence and the light emitting diode the basics and technology of leds and the luminescence properties of the materials

CERN Document Server

Williams, E W; Pamplin, BR

2013-01-01

Luminescence and the Light Emitting Diode: The Basics and Technology of LEDS and the Luminescence Properties of the Materials focuses on the basic physics and technology of light emitting diodes (LEDS) and pn junction lasers as well as their luminescence properties. Optical processes in semiconductors and the useful devices which can be made are discussed. Comprised of 10 chapters, this book begins with an introduction to the crystal structure and growth, as well as the optical and electrical properties of LED materials. The detailed fabrication of the LED is then considered, along with the lu

Evaluation of the gravimetric tetraphenylarsonium method for the determination of Tc(VII)

International Nuclear Information System (INIS)

Pacer, R.A.

1980-01-01

Solubility losses in the gravimetric tetraphenylarsonium method for determining pertechnetate have been evaluated. Liquid scintillation counting was used to measure the β - activity of 99 Tc in the filtrate, and indicated solubility losses of about 1% in analyses yielding 40 to 50 mg of precipitate. The solubility product of (C 6 H 5 ) 4 AsTcO 4 is estimated to be (8.6 +- 0.2) x 10 -10 at room temperature (24 to 25 0 ), and Ksub(sp) for (C 6 H 5 ) 4 AsReO 4 at approximately 21 to 23 0 is estimated at (2.6 +- 0.3) x 10 -9 . Both values are satisfactory for gravimetric purposes, but to keep solubility losses within 1% at least 40 mg of (C 6 H 5 ) 4 AsTcO 4 or 80 mg of (C 6 H 5 ) 4 AsReO 4 should be obtained (assuming 20 ml of solution, 20 to 30% excess of precipitant, and 6 or 7 washes with 5-ml portions of distilled water). (author)

Praseodymium - A Competent Dopant for Luminescent Downshifting and Photocatalysis in ZnO Thin Films

Science.gov (United States)

Narayanan, Nripasree; Deepak, N. K.

2018-05-01

Highly transparent and conducting Zinc oxide (ZnO) thin films doped with Praseodymium (Pr) were deposited on glass substrates by using the spray pyrolysis method. The X-ray diffraction (XRD) analysis revealed the polycrystallinity of the deposited films with a hexagonal wurtzite structure, whereas the energy-dispersive X-ray spectroscopy (EDX) analysis confirmed the incorporation of Pr in the films. The optical energy gap decreased by Pr doping due to the merging of the conduction band with the impurity bands formed within the forbidden gap. The room temperature photoluminescence spectra of the Pr-doped film showed enhancement of visible emission, suggesting efficient luminescent downshifting. The photocatalytic activity of the Pr-doped films is higher than that of undoped films due to the effective suppression of the rapid recombination of the photo-generated electron-hole pairs. The impurity levels formed within the forbidden gap act as efficient luminescent centers and electron traps, which lead to luminescent downshifting and enhanced photocatalytic activity.

Ratiometric Time-Gated Luminescence Probe for Nitric Oxide Based on an Apoferritin-Assembled Lanthanide Complex-Rhodamine Luminescence Resonance Energy Transfer System.

Science.gov (United States)

Tian, Lu; Dai, Zhichao; Liu, Xiangli; Song, Bo; Ye, Zhiqiang; Yuan, Jingli

2015-11-03

Using apoferritin (AFt) as a carrier, a novel ratiometric luminescence probe based on luminescence resonance energy transfer (LRET) between a Tb(3+) complex (PTTA-Tb(3+)) and a rhodamine derivative (Rh-NO), PTTA-Tb(3+)@AFt-Rh-NO, has been designed and prepared for the specific recognition and time-gated luminescence detection of nitric oxide (NO) in living samples. In this LRET probe, PTTA-Tb(3+) encapsulated in the core of AFt is the energy donor, and Rh-NO, a NO-responsive rhodamine derivative, bound on the surface of AFt is the energy acceptor. The probe only emits strong Tb(3+) luminescence because the emission of rhodamine is switched off in the absence of NO. Upon reaction with NO, accompanied by the turn-on of rhodamine emission, the LRET from Tb(3+) complex to rhodamine occurs, which results in the remarkable increase and decrease of the long-lived emissions of rhodamine and PTTA-Tb(3+), respectively. After the reaction, the intensity ratio of rhodamine emission to Tb(3+) emission, I565/I539, is ∼24.5-fold increased, and the dose-dependent enhancement of I565/I539 shows a good linearity in a wide concentration range of NO. This unique luminescence response allowed PTTA-Tb(3+)@AFt-Rh-NO to be conveniently used as a ratiometric probe for the time-gated luminescence detection of NO with I565/I539 as a signal. Taking advantages of high specificity and sensitivity of the probe as well as its good water-solubility, biocompatibility, and cell membrane permeability, PTTA-Tb(3+)@AFt-Rh-NO was successfully used for the luminescent imaging of NO in living cells and Daphnia magna. The results demonstrated the efficacy of the probe and highlighted it's advantages for the ratiometric time-gated luminescence bioimaging application.

Luminescence properties of Yb:Nd:Tm:KY3F10 nanophosphor and thermal treatment effects

International Nuclear Information System (INIS)

Gomes, Laércio; Linhares, Horácio Marconi da Silva M.D.; Ichikawa, Rodrigo Uchida; Martinez, Luis Gallego; Ranieri, Izilda Marcia

2015-01-01

In this work, we present the spectroscopic properties of KY 3 F 10 (KY3F) nanocrystals activated with thulium and codoped with ytterbium and neodymium ions. The most important processes that lead to the thulium upconversion emissions in the blue region were identified. A time-resolved luminescence spectroscopy technique was employed to measure the luminescence decays and to determine the most important mechanisms involved in the upconversion process that populates 1 G 4 (Tm 3+ ) excited states. Analysis of the energy-transfer processes dynamics using selective pulsed-laser excitations in Yb:Nd:Tm, Nd:KY3F nanocrystals shows that the direct energy transfer from Nd 3+ to Tm 3+ ions is the mechanism responsible for the 78% of the blue upconversion luminescence in the Yb:Nd:Tm:KY3F when compared with the Yb:Nd:Tm:KY3F bulk crystal for an laser excitation at 802 nm. An investigation of the 1 G 4 level luminescence kinetic of Tm 3+ in Yb/Nd/Tm system revealed that the luminescence efficiency ( 1 G 4 ) starts with a very low value (0.38%) for the synthesized nanocrystal (as grown) and strongly increases to 97% after thermal treatment at 550 °C for 6 h under argon flow. As a consequence of the thermal treatment at T=550 °C, the contributions of the (Nd×Tm) (Up 1 ) and (Nd×Yb×Tm) (Up 2 ) upconversion processes to the 1 G 4 luminescence are 33% (Up 1 ) and 67% for Up 2 . Up 2 process represented by Nd 3+ ( 4 F 3/2 )→Yb 3+ ( 2 F 7/2 ) followed by Yb 3+ ( 2 F 5/2 )→Tm ( 3 H 4 )→Tm 3+ ( 1 G 4 ) was previously reported as the main mechanism to produce the blue luminescence in Yb:Nd:Tm:YLiF 4 and KY 3 F 10 bulk crystals. Results of X-ray diffraction analysis of nanopowder using the Rietveld method reveled that crystallite sizes remain unchanged (12–14 nm) after thermal treatments with T≤400 °C, while the 1 G 4 luminescence efficiency strongly increases from 0.38% (T=25 °C) to 12% (T=400 °C). Results shown that the Nd 3+ ions distribution has a concentration

Luminescence properties of the Sm-doped borate glasses

Energy Technology Data Exchange (ETDEWEB)

Kindrat, I.I. [University of Zielona Góra, Institute of Physics, Division of Spectroscopy of Functional Materials, 4a Szafrana Street, 65-516 Zielona Góra (Poland); Padlyak, B.V., E-mail: B.Padlyak@if.uz.zgora.pl [University of Zielona Góra, Institute of Physics, Division of Spectroscopy of Functional Materials, 4a Szafrana Street, 65-516 Zielona Góra (Poland); Vlokh Institute of Physical Optics, 23 Dragomanov Street, 79-005 Lviv (Ukraine); Drzewiecki, A. [University of Zielona Góra, Institute of Physics, Division of Spectroscopy of Functional Materials, 4a Szafrana Street, 65-516 Zielona Góra (Poland)

2015-10-15

The optical absorption and photoluminescence (emission and excitation) spectra as well as decay kinetics of a series of the Sm-doped glasses with Li{sub 2}B{sub 4}O{sub 7}, LiKB{sub 4}O{sub 7}, CaB{sub 4}O{sub 7}, and LiCaBO{sub 3} compositions were investigated and analysed. The Li{sub 2}B{sub 4}O{sub 7}:Sm, LiKB{sub 4}O{sub 7}:Sm, CaB{sub 4}O{sub 7}:Sm, and LiCaBO{sub 3}:Sm glasses of high optical quality have been obtained from the corresponding polycrystalline compounds in the air atmosphere, using a standard glass technology. On the basis of electron paramagnetic resonance (EPR) and optical spectra analysis it was shown that the samarium impurity is incorporated into the glass network as Sm{sup 3+} (4f{sup 5}, {sup 6}H{sub 5/2}) ions, exclusively. All observed 4f – 4f transitions of the Sm{sup 3+} centres in the optical absorption and luminescence spectra of the investigated glasses are identified. Most intense emission band of the Sm{sup 3+} ions peaked about 598 nm ({sup 4}G{sub 5/2} → {sup 6}H{sub 7/2} transition) is characterised by a single exponential decay with typical lifetime values, which depend on the basic glass composition as well as concentration and local structure of the Sm{sup 3+} luminescence centres. The quantum efficiency has been evaluated for observed transitions of the Sm{sup 3+} centres using obtained experimental lifetimes and radiative lifetimes calculated by Judd–Ofelt theory. The calculated high quantum efficiencies and measured quantum yields of luminescence show that the investigated borate glasses are perspective luminescence materials. Energy transfer from the Ce{sup 3+} non-controlled impurity and intrinsic luminescence centres to the Sm{sup 3+} centres has been observed. Peculiarities of the Sm{sup 3+} local structure in the network of investigated glasses have been discussed based on the obtained spectroscopic results and structural data. - Highlights: • The Sm-doped Li{sub 2}B{sub 4}O{sub 7}, LiKB{sub 4}O{sub 7}, Ca

Novel Mechano-Luminescent Sensors Based on Piezoelectric/Electroluminescent Composites

Directory of Open Access Journals (Sweden)

Yunzhang Fang

2011-04-01

Full Text Available A high-sensitivity mechano-luminescent sensor was fabricated on the basis of piezoelectric/electroluminescent composites. The working principle of this mechano-luminescent sensor was elucidated by analyzing the relationship between the piezoelectric-induced charges and the electroluminescent effects. When a stress is applied on the piezoelectric layer, electrical charges will be induced at both the top and bottom sides of the piezoelectric layer. The induced electrical charges will lead to a light output from the electroluminescent layer, thus producing a mechano-luminescence effect. By increasing the vibration strength or frequency applied, the mechano-luminescence output can be obviously enhanced. Mechano-luminescence sensors have potential in smart stress-to-light devices, such as foot-stress-distribution-diagnosis systems and dynamic-load-monitors for bridge hanging cables.

Cerenkov Luminescence Tomography for In Vivo Radiopharmaceutical Imaging

Directory of Open Access Journals (Sweden)

Jianghong Zhong

2011-01-01

Full Text Available Cerenkov luminescence imaging (CLI is a cost-effective molecular imaging tool for biomedical applications of radiotracers. The introduction of Cerenkov luminescence tomography (CLT relative to planar CLI can be compared to the development of X-ray CT based on radiography. With CLT, quantitative and localized analysis of a radiopharmaceutical distribution becomes feasible. In this contribution, a feasibility study of in vivo radiopharmaceutical imaging in heterogeneous medium is presented. Coupled with a multimodal in vivo imaging system, this CLT reconstruction method allows precise anatomical registration of the positron probe in heterogeneous tissues and facilitates the more widespread application of radiotracers. Source distribution inside the small animal is obtained from CLT reconstruction. The experimental results demonstrated that CLT can be employed as an available in vivo tomographic imaging of charged particle emitters in a heterogeneous medium.

Luminescent solar concentrator

Directory of Open Access Journals (Sweden)

Tugce Tosun

2015-07-01

Full Text Available Luminescent solar concentrator (LSC is a device that has luminescent molecules embedding or topping polymeric or glass waveguide to generate electricity from sunlight with a photovoltaic cell attachment. LSCs can be employed both in small and large scale projects, independent on the direction or angle of the surface with respect to the sun, promising more freedom for integration in urban environments compared to the traditional PV systems. The aim of the SEB&C PDEng project is to investigate the applicability of this innovative technology in the built environment and to bridge the gap of knowledge linking societal, design and technological aspects. The final goal is to exhibit potential application concepts of LSC developed by co-creative methods at SPARK campus which is a hub for open innovation in built environment. Necessity of a paradigm shift towards sustainable and smart cities came into being due to the significant increase in energy demand of the buildings. The challenge is to increase renewable sources in the energy mix while designing aesthetic environments. Thus, building integrated renewable energy technologies represent a great opportunity to help overcome this current challenge. Smart energy, energy efficiency and use of renewable sources are key aspects to be considered nowadays and many innovative technologies need further exploitation to be commercially viable, such as luminescent solar concentrator.

Estimation of the internal structure of Trans-Mexican volcanic belt by gravimetric data

International Nuclear Information System (INIS)

Flores R, J.H.

1994-01-01

The regional gravimetric data of Trans-Mexican volcanic belt and surroundings, has been analyzed in order to estimate the depth of its internal structure. The short profiles with N-S orientation give a model of four shells with an average depth in the rank 24, 34, 56 and 83 kilometers. Only the profiles included between 97 West degrees to 102 West degrees give a depth of crust larger than the rest of the profiles with the same orientation. This profiles are associated with that of the Valleys of Toluca, D.F. and Puebla where the maximum crust thickness was estimated. The 3 long profiles with S-W orientation, give a model of 3 shells. The tendency of the first shell has a cortical thickness of 38 kilometers in the latitude of 18 North degrees. This tendency to increase the depth in the crust is associated with the minimum gravimetric in the map of Bouguer anomaly. (Author)

Luminescence and circularly polarized luminescence of macrocyclic Eu(III) and Tb(III) complexes embedded in xerogel and sol-gel SiO2 glasses

International Nuclear Information System (INIS)

Morita, M.; Rau, D.; Kai, T.

2002-01-01

Luminescence, time-resolved luminescence, circularly polarized luminescence (CPL) and decay profiles of Ln(III)(15-crownether-5) (Ln=Ce, Sm, Eu, Tb) and Tb(III)-(R),(S)-cyclen derivative complexes doped in xerogel and sol-gel silica glasses are measured at temperatures down to 10 K to characterize luminescence properties and the electronic structure in the excited states. Luminescence spectral profiles and calculation of crystal field parameters (B 0 (2) ,B 2 (2) ) in the 5 D 0 → 7 F J (J=1,2) transition give evidence of the fact that the pentagonal and planar structure of Eu(III) (15-crownether-5) does hold in xerogel and sol-gel glasses prepared at temperatures below 100 deg. C. As annealing temperatures are increased from 80 deg. C to 750 deg. C, Eu(III) complexes in sol-gel glasses are found to decompose gradually to SiO 2 :Eu 3+ . Tb(III)-(R) and (S)-cyclen derivative complexes in xerogel reveal at room temperature and 10 K sharp CPL spectra with luminescence dissymmetry factors g lum =-0.1 and 0.1, respectively. These complexes doped in sol-gel glasses represent luminescence characteristics of rare earth ions encapsulated in the nano-porous host

Magnetometric and gravimetric surveys in fault detection over Acambay System

Science.gov (United States)

García-Serrano, A.; Sanchez-Gonzalez, J.; Cifuentes-Nava, G.

2013-05-01

In commemoration of the centennial of the Acambay intraplate earthquake of November 19th 1912, we carry out gravimetric and magnetometric surveys to define the structure of faults caused by this event. The study area is located approximately 11 km south of Acambay, in the Acambay-Tixmadeje fault system, where we performed two magnetometric surveys, the first consisting of 17 lines with a spacing of 35m between lines and 5m between stations, and the second with a total of 12 lines with the same spacing, both NW. In addition to these two lines we performed gravimetric profiles located in the central part of each magnetometric survey, with a spacing of 25m between stations, in order to correlate the results of both techniques, the lengths of such profiles were of 600m and 550m respectively. This work describes the data processing including directional derivatives, analytical signal and inversion, by means of which we obtain results of magnetic variations and anomaly traits highly correlated with those faults. It is of great importance to characterize these faults given the large population growth in the area and settlement houses on them, which involves a high risk in the security of the population, considering that these are active faults and cannot be discard earthquakes associated with them, so it is necessary for the authorities and people have relevant information to these problem.

Polymethylmethacrylate-based luminescent solar concentrators with bottom-mounted solar cells

International Nuclear Information System (INIS)

Zhang, Yi; Sun, Song; Kang, Rui; Zhang, Jun; Zhang, Ningning; Yan, Wenhao; Xie, Wei; Ding, Jianjun; Bao, Jun; Gao, Chen

2015-01-01

Graphical abstract: - Highlights: • Bottom-mounted luminescent solar concentrators on dye-doped plates were studied. • The mechanism of transport process was proposed. • The fabricated luminescent solar concentrator achieved a gain of 1.38. • Power conversion efficiency of 5.03% was obtained with cell area coverage of 27%. • The lowest cost per watt of $1.89 was optimized with cell area coverage of 18%. - Abstract: Luminescent solar concentrators offer an attractive approach to concentrate sunlight economically without tracking, but the narrow absorption band of luminescent materials hinders their further development. This paper describes bottom-mounted luminescent solar concentrators on dye-doped polymethylmethacrylate plates that absorb not only the waveguided light but also the transmitted sunlight and partial fluorescent light in the escape cone. A series of bottom-mounted luminescent solar concentrators with size of 78 mm × 78 mm × 7 mm were fabricated and their gain and power conversion efficiency were investigated. The transport process of the waveguided light and the relationship between the bottom-mounted cells were studied to optimize the performance of the device. The bottom-mounted luminescent solar concentrator with cell area coverage of 9% displayed a cell gain of 1.38, to our best knowledge, which is the highest value for dye-doped polymethylmethacrylate plate luminescent solar concentrators. Power conversion efficiency as high as 5.03% was obtained with cell area coverage of 27%. Furthermore, the bottom-mounted luminescent solar concentrator was found to have a lowest cost per watt of $1.89 with cell area coverage of 18%. These results suggested that the fabricated bottom-mounted luminescent solar concentrator may have a potential in low-cost building integrated photovoltaic application

Design, synthesis and characterization of a highly luminescent Eu-complex monomer featuring thenoyltrifluoroacetone and 5-acryloxyethoxymethyl-8-hydroxyquinoline

Energy Technology Data Exchange (ETDEWEB)

Xu Cunjin [State Key Laboratory of Chemical Engineering, Department of Chemical and Biochemical Engineering, Zhejiang University, Hangzhou 310027 (China); College of Material, Chemistry and Chemical Engineering, Hangzhou Normal University, Hangzhou 310036 (China); Li Bogeng, E-mail: bgli@zju.edu.cn [State Key Laboratory of Chemical Engineering, Department of Chemical and Biochemical Engineering, Zhejiang University, Hangzhou 310027 (China); Wan Jintao; Bu Zhiyang [State Key Laboratory of Chemical Engineering, Department of Chemical and Biochemical Engineering, Zhejiang University, Hangzhou 310027 (China)

2011-08-15

A multi-functional ligand, 5-acryloxyethoxymethyl-8-hydroxyquinoline (Hamq), was synthesized, which contained a polymerizable C=C double bond for the copolymerization with other vinyl monomers and acted as photon antenna able to transfer energy to Eu{sup 3+} ions effectively. The triplet state energy of Hamq was determined to be 22,370 cm{sup -1} via the phosphorescence spectra of Hamq and its gadolinium complex. The title complex monomer Eu(tta){sub 2}(amq) was prepared by coordination reaction of Hamq with europium isopropoxide and 2-thenoyltrifluoroacetone (Htta) in dry organic solvents under argon atmosphere and characterized by elemental analysis and IR spectrum. The photophysical properties of the complex were studied in detail with UV-vis, luminescence spectra, luminescence lifetime and quantum yield. The complex exhibited nearly monochromatic red emission at 612 nm, a remarkable luminescence quantum yield at room temperature (30.6%) upon ligand excitation and a long {sup 5}D{sub 0} lifetime (389 {mu}s), which indicated that the ligand Hamq could sensitize the luminescence of Eu(III) ion efficiently in Eu(tta){sub 2}(amq), resulting in a strong luminescence of its copolymer poly[MMA-co-Eu(TTA){sub 2}(amq)] under UV excitation. The excellent luminescence properties of the complex made it not only a promising light-conversion molecular device but also an excellent luminescent monomer. - Highlights: >iWe designed and synthesized a highly luminescent Eu-complex monomer. > Quantum yield and lifetime of the complex are 30.6% and 389 {mu}s, respectively. > Excellent luminescence of the complex made it an excellent luminescent monomer.

Kinetics of infrared stimulated luminescence from feldspars

DEFF Research Database (Denmark)

Jain, Mayank; Sohbati, Reza; Guralnik, Benny

2015-01-01

thermal and optical, of the infrared stimulated luminescence signal from feldspar. Based on the application of this model, it is concluded that different infra-red stimulated luminescence emissions (UV, blue, yellow and far-red) follow the same kinetics, and, therefore, involve participation of the same...

Process for obtaining luminescent glass layers

International Nuclear Information System (INIS)

Heindi, R.; Robert, A.

1984-01-01

Process for obtaining luminescent glass layers, application to the production of devices provided with said layers and to the construction of photoscintillators. The process comprises projecting onto a support, by cathodic sputtering, the material of at least one target, each target including silica and at least one chemical compound able to give luminescent centers, such as a cerium oxide, so as to form at least one luminescent glass layer of the said support. The layer or layers formed preferably undergo a heat treatment such as annealing in order to increase the luminous efficiency thereof. It is in this way possible to form a scintillating glass layer on the previously frosted entrance window of a photomultiplier in order to obtain an integrated photoscintillator

NaCl samples for optical luminescence dosimetry

International Nuclear Information System (INIS)

Catli, S.

2005-01-01

Optically stimulated luminescence (OSL) have been used broadly for luminescence dosimetry and dating. In many cases, it has been pointed out that the decay of the OSL do not generally behave according to a simple exponential function. In this study the Infra-red stimulated luminescence (IRSL) intensity from NaCl samples were experimentally measured. The decay curves for this sample were fitted to some functions and it is in good agreement with the function y = α + b exp(-cx). The IRSL decay curves from NaCl using different β-doses have been obtained and investigated their dose response

Application, advantages and limitations of high-density gravimetric surveys compared with three-dimensional geological modelling in dolomite stability investigations

OpenAIRE

Breytenbach, I J; Bosch, P J A

2011-01-01

The article discusses the nature of the gravimetric survey as applied and used in dolomite stability investigations on areas underlain by the Chuniespoort Group in South Africa. A short discussion is given on the gravimetric survey procedure along with its uses and alternative methods. Finally, two case studies illustrate the application of the method on a high-density survey grid spacing in comparison with three-dimensional geological modelling based on the lithology and karst weathering hor...

Luminescent polymethyl methacrylate modified by gamma radiation

Energy Technology Data Exchange (ETDEWEB)

Morais, Guilherme F. [Faculdade de Tecnologia de Sao Paulo (FATEC-ZL), Sao Paulo, SP (Brazil); Forster, Pedro L.; Marchini, Leonardo G.; Lugao, Ademar B.; Parra, Duclerc F., E-mail: dfparra@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

2011-07-01

Thin films of PMMA (polymethyl methacrylate) doped with luminescent complexes have been studied and developed for applications in advanced technologies. The problem of stability of these films is focused in this study. Films stabilization by reaction with fluorinated monomers is a recent study that aims to increase its luminescence properties for long time. The films were prepared by dilution of PMMA in chloroform with addition of europium complex, at proportion of 5% by weight of polymer. The luminescent polymer films were obtained by casting. Thin layer slides of the film were separated in three parts. One was reacted with fluorinated monomers (C{sub 2}F{sub 4}) in closed reactor for 48 hours. A second part was reacted with C{sub 2}F{sub 4} after irradiation in gamma source at 5 kGy in simultaneous process. The last part was used as obtained. The luminescent polymer matrices were characterized using the techniques of infrared (FTIR) and thermogravimetry (TGA/DTG). Samples of the films were, in presence of fluorine monomers, exposed to ionizing radiation in dose of 5 kGy, for react with monomers in the doped polymer surface. In this case the effects of radiation were evaluated on the luminescent films. (author)

On luminescence lifetimes in quartz

International Nuclear Information System (INIS)

Chithambo, M.L.; Galloway, R.B.

2000-01-01

In this paper we present results of investigations concerning the time dependence of luminescence emission relative to the time of stimulation in quartz. Measurements of time-resolved spectra were performed on a new versatile pulsed light emitting diode system using 525 nm stimulation, an 11 μs duration pulse, a repetition rate of 11 kHz and a 64 μs dynamic range. Effects on luminescence lifetime resulting from sample treatments such as optical stimulation, irradiation, and preheating, are reported

Fabrication of luminescent porous silicon with stain etches and evidence that luminescence originates in amorphous layers

Science.gov (United States)

Fathauer, R. W.; George, T.; Ksendzov, A.; Lin, T. L.; Pike, W. T.; Vasquez, R. P.; Wu, Z.-C.

1992-01-01

Simple immersion of Si in stain etches of HF:HNO3:H2O or NaNO2 in aqueous HF was used to produce films exhibiting luminescence in the visible similar to that of anodically-etched porous Si. All of the luminescent samples consist of amorphous porous Si in at least the near surface region. No evidence was found for small crystalline regions within these amorphous layers.

Experimental aspects of buoyancy correction in measuring reliable highpressure excess adsorption isotherms using the gravimetric method.

Science.gov (United States)

Nguyen, Huong Giang T; Horn, Jarod C; Thommes, Matthias; van Zee, Roger D; Espinal, Laura

2017-12-01

Addressing reproducibility issues in adsorption measurements is critical to accelerating the path to discovery of new industrial adsorbents and to understanding adsorption processes. A National Institute of Standards and Technology Reference Material, RM 8852 (ammonium ZSM-5 zeolite), and two gravimetric instruments with asymmetric two-beam balances were used to measure high-pressure adsorption isotherms. This work demonstrates how common approaches to buoyancy correction, a key factor in obtaining the mass change due to surface excess gas uptake from the apparent mass change, can impact the adsorption isotherm data. Three different approaches to buoyancy correction were investigated and applied to the subcritical CO 2 and supercritical N 2 adsorption isotherms at 293 K. It was observed that measuring a collective volume for all balance components for the buoyancy correction (helium method) introduces an inherent bias in temperature partition when there is a temperature gradient (i.e. analysis temperature is not equal to instrument air bath temperature). We demonstrate that a blank subtraction is effective in mitigating the biases associated with temperature partitioning, instrument calibration, and the determined volumes of the balance components. In general, the manual and subtraction methods allow for better treatment of the temperature gradient during buoyancy correction. From the study, best practices specific to asymmetric two-beam balances and more general recommendations for measuring isotherms far from critical temperatures using gravimetric instruments are offered.

Controlled fabrication of luminescent and magnetic nanocomposites

Science.gov (United States)

Ma, Yingxin; Zhong, Yucheng; Fan, Jing; Huang, Weiren

2018-03-01

Luminescent and magnetic multifunctional nanocomposite is in high demand and widely used in many scales, such as drug delivery, bioseparation, chemical/biosensors, and so on. Although lots of strategies have been successfully developed for the demand of multifunctional nanocomposites, it is not easy to prepare multifunctional nanocomposites by using a simple method, and satisfy all kinds of demands simultaneously. In this work, via a facile and versatile method, luminescent nanocrystals and magnetic nanoparticles were successfully synthesized through self-assembly under vigorous stirring and ultrasonic treatment. These multifunctional nanocomposites are not only water stable but also find wide application such as magnetic separation and concentration with a series of moderate speed, multicolor fluorescence at different emission wavelength, high efficiency of the excitation and emission, and so on. By changing different kinds of luminescent nanocrystals and controlling the amount of luminescent and magnetic nanoparticles, a train of multifunctional nanocomposites was successfully fabricated via a versatile and robust method.

Luminescence evolution from alumina ceramic surface before flashover under direct and alternating current voltage in vacuum

Energy Technology Data Exchange (ETDEWEB)

Su, Guo-Qiang; Wang, Yi-Bo; Song, Bai-Peng; Mu, Hai-Bao, E-mail: haibaomu@xjtu.edu.cn, E-mail: gjzhang@xjtu.edu.cn; Zhang, Guan-Jun, E-mail: haibaomu@xjtu.edu.cn, E-mail: gjzhang@xjtu.edu.cn [State Key Laboratory of Electrical Insulation and Power Equipment, School of Electrical Engineering, Xi’an Jiaotong University, Xi’an, Shaanxi 710049 (China); Li, Feng; Wang, Meng [Institute of Fluid Physics, China Academy of Engineering Physics, Mianyang, Sichuan 621900 (China)

2016-06-15

The luminescence evolution phenomena from alumina ceramic surface in vacuum under high voltage of direct and alternating current are reported, with the voltage covering a large range from far below to close to the flashover voltage. Its time resolved and spatial distributed behaviors are examined by a photon counting system and an electron-multiplying charge-coupled device (EMCCD) together with a digital camera, respectively. The luminescence before flashover exhibits two stages as voltage increasing, i.e., under a relative low voltage (Stage A), the luminescence is ascribed to radiative recombination of hetero-charges injected into the sample surface layer by Schottky effect; under a higher voltage (Stage B), a stable secondary electron emission process, resulting from the Fowler-Nordheim emission at the cathode triple junction (CTJ), is responsible for the luminescence. Spectrum analysis implies that inner secondary electrons within the surface layer of alumina generated during the SSEE process also participate in the luminescence of Stage B. A comprehensive interpretation of the flashover process is formulated, which might promote a better understanding of flashover issue in vacuum.

Determination of U, Th and K for optically stimulated luminescence dating by NAA

International Nuclear Information System (INIS)

Qin Yali; Chen Zhe; Wu Weiming

2010-01-01

Optically stimulated luminescence dating techniques have been widely used in northern Loess ancient soil series and recorded climate environment change, ancient earthquake, the ancients site and archaeology research. The determination of U, Th and K using neutron activation analysis (NAA) has been optimized for the samples related to OSL dating research. The procedure for determination of U, Th, K in loess have been fixed by using Miniature neutron source reactor. This procedure of NAA will provide a reliable data base for optically stimulated luminescence dating research. (authors)

Luminescence imaging using radionuclides: a potential application in molecular imaging

International Nuclear Information System (INIS)

Park, Jeong Chan; Il An, Gwang; Park, Se-Il; Oh, Jungmin; Kim, Hong Joo; Su Ha, Yeong; Wang, Eun Kyung; Min Kim, Kyeong; Kim, Jung Young; Lee, Jaetae; Welch, Michael J.; Yoo, Jeongsoo

2011-01-01

Introduction: Nuclear and optical imaging are complementary in many aspects and there would be many advantages when optical imaging probes are prepared using radionuclides rather than classic fluorophores, and when nuclear and optical dual images are obtained using single imaging probe. Methods: The luminescence intensities of various radionuclides having different decay modes have been assayed using luminescence imaging and in vitro luminometer. Radioiodinated Herceptin was injected into a tumor-bearing mouse, and luminescence and microPET images were obtained. The plant dipped in [ 32 P]phosphate solution was scanned in luminescence mode. Radio-TLC plate was also imaged in the same imaging mode. Results: Radionuclides emitting high energy β + /β - particles showed higher luminescence signals. NIH3T6.7 tumors were detected in both optical and nuclear imaging. The uptake of [ 32 P]phosphate in plant was easily followed by luminescence imaging. Radio-TLC plate was visualized and radiochemical purity was quantified using luminescence imaging. Conclusion: Many radionuclides with high energetic β + or β - particles during decay were found to be imaged in luminescence mode due mainly to Cerenkov radiation. 'Cerenkov imaging' provides a new optical imaging platform and an invaluable bridge between optical and nuclear imaging. New optical imaging probes could be easily prepared using well-established radioiodination methods. Cerenkov imaging will have more applications in the research field of plant science and autoradiography.

Judd-Ofelt analysis and temperature dependent upconversion luminescence of Er{sup 3+}/Yb{sup 3+} codoped Gd{sub 2}(MoO{sub 4}){sub 3} phosphor

Energy Technology Data Exchange (ETDEWEB)

Lu, Hongyu [Department of Physics, Harbin Institute of Technology, Harbin 150001 (China); Gao, Yachen [College of Electronic Engineering, Heilongjiang University, Harbin 150080 (China); Hao, Haoyue; Shi, Guang [Department of Physics, Harbin Institute of Technology, Harbin 150001 (China); Li, Dongyu [Department of Physics, Lingnan Normal University, Zhanjiang 524048 (China); Song, Yinglin [Department of Physics, Harbin Institute of Technology, Harbin 150001 (China); Wang, Yuxiao, E-mail: wangyx@hit.edu.cn [Department of Physics, Harbin Institute of Technology, Harbin 150001 (China); Zhang, Xueru, E-mail: xrzhang@hit.edu.cn [Department of Physics, Harbin Institute of Technology, Harbin 150001 (China)

2017-06-15

Although lanthanide doped luminescent materials have been extensively investigated, a quantitative analysis of how temperature affects upconversion luminescence is still incomplete. The Gd{sub 2}(MoO{sub 4}){sub 3}:Er{sup 3+}/Yb{sup 3+} phosphor is synthetized by sol-gel method. Based on the absorption spectra of Er{sup 3+} ions, J-O intensity parameters and radiative transition probabilities are computed to estimate the optical properties. In view of ion-phonon interaction, the phonon-assisted energy transfer and multiphonon relaxation are responsible for the temperature dependent luminescence. Additionally, cross relaxation probability for {sup 4}I{sub 11/2}+{sup 4}I{sub 11/2}→{sup 4}I{sub 15/2}+{sup 4}F{sub 7/2} is determined to be 240 s{sup −1} through quantitative simulation of ion-ion interaction. These meaningful results are of vital values for the field of laser crystal and optical temperature sensing.

Luminescence and radiocarbon dating of raised beach sediments, Bunger Hills, East Antarctica

International Nuclear Information System (INIS)

Augustinus, P.C.; Duller, G.A.T.

2002-01-01

Luminescence and radiocarbon dating of raised marine sediments from the Bunger Hills, East Antarctica, demonstrates that luminescence methods can be applied to such poorly bleached sediments as long as the luminescence behaviour of the sediments is understood. This is essential as the complete zeroing of the luminescence signal due to light exposure is required to allow an accurate age for the sediment accumulation. Unfortunately, independent checks on the luminescence ages are rare. In the present study, some independent age control is provided by AMS radiocarbon ages from shell obtained from and adjacent to the luminescence dated horizons, although the radiocarbon ages may suffer to some degree from variability in the marine reservoir effect. Application of the single aliquot luminescence technique to feldspar grains from the marine sediments demonstrated that the luminescence behaviour of the sediments was complex. For each sample, 18 replicate paleodose estimates were used to demonstrate whether the sediments were well bleached before deposition. Optically, well-bleached samples give younger luminescence ages, whilst poorly bleached samples often give excessively old ages compared to the associated radiocarbon-dated material. (author)

Geopotential coefficient determination and the gravimetric boundary value problem: A new approach

Science.gov (United States)

Sjoeberg, Lars E.

1989-01-01

New integral formulas to determine geopotential coefficients from terrestrial gravity and satellite altimetry data are given. The formulas are based on the integration of data over the non-spherical surface of the Earth. The effect of the topography to low degrees and orders of coefficients is estimated numerically. Formulas for the solution of the gravimetric boundary value problem are derived.

Magnetic-luminescent spherical particles synthesized by ultrasonic spray pyrolysis

International Nuclear Information System (INIS)

Michel, Norma L; Hirata, Gustavo A; Flores, Dora L

2015-01-01

The combination of magnetic and luminescent properties in a single particle system, opens-up a wide range of potential applications in biotechnology and biomedicine. In this work, we performed the synthesis of magnetic-luminescent Gd 2 O 3 :Eu 3+ @Fe 2 O 3 particles by ultrasonic spray pyrolysis performed in a tubular furnace. In order to achieve the composite formation, commercial superparamagnetic Fe 3 O 4 nanoparticles were coated with a luminescent Eu 3+ -doped Gd 2 O 3 shell in a low-cost one-step process. The spray pyrolysis method yields deagglomerated spherical shape magneto/luminescent particles. The photoluminescence spectra under UV excitation (λ Exc = 265 nm) of the magnetic Gd 2 O 3 :Eu 3+ @Fe 2 O 3 compound showed the characteristic red emission of Eu 3+ (λ Em = 612 nm). This magneto/luminescent system will find applications in biomedicine and biotechnology. (paper)

Luminescence Properties of Surface Radiation-Induced Defects in Lithium Fluoride

Science.gov (United States)

Voitovich, A. P.; Kalinov, V. S.; Martynovich, E. F.; Novikov, A. N.; Runets, L. P.; Stupak, A. P.

2013-11-01

Luminescence and luminescence excitation spectra are recorded for surface radiation-induced defects in lithium fluoride at temperatures of 77 and 293 K. The presence of three bands with relatively small intensity differences is a distinctive feature of the excitation spectrum. These bands are found to belong to the same type of defects. The positions of the peaks and the widths of the absorption and luminescence bands for these defects are determined. The luminescence decay time is measured. All the measured characteristics of these surface defects differ from those of previously known defects induced by radiation in the bulk of the crystals. It is found that the luminescence of surface defects in an ensemble of nanocrystals with different orientations is not polarized. The number of anion vacancies in the surface defects is estimated using the polarization measurements. It is shown that radiative scattering distorts the intensity ratios of the luminescence excitation bands located in different spectral regions.

New Nanomaterials and Luminescent Optical Sensors for Detection of Hydrogen Peroxide

Directory of Open Access Journals (Sweden)

Natalia A. Burmistrova

2015-10-01

Full Text Available Accurate methods that can continuously detect low concentrations of hydrogen peroxide (H2O2 have a huge application potential in biological, pharmaceutical, clinical and environmental analysis. Luminescent probes and nanomaterials are used for fabrication of sensors for H2O2 that can be applied for these purposes. In contrast to previous reviews focusing on the chemical design of molecular probes for H2O2, this mini-review highlights the latest luminescent nanoparticular materials and new luminescent optical sensors for H2O2 in terms of the nanomaterial composition and luminescent receptor used in the sensors. The nanomaterial section is subdivided into schemes based on gold nanoparticles, polymeric nanoparticles with embedded enzymes, probes showing aggregation-induced emission enhancement, quantum dots, lanthanide-based nanoparticles and carbon based nanomaterials, respectively. Moreover, the sensors are ordered according to the type of luminescent receptor used within the sensor membranes. Among them are lanthanide complexes, metal-ligand complexes, oxidic nanoparticles and organic dyes. Further, the optical sensors are confined to those that are capable to monitor the concentration of H2O2 in a sample over time or are reusable. Optical sensors responding to gaseous H2O2 are not covered. All nanomaterials and sensors are characterized with respect to the analytical reaction towards H2O2, limit of detection (LOD, analytical range, electrolyte, pH and response time/incubation time. Applications to real samples are given. Finally, we assess the suitability of the nanomaterials to be used in membrane-based sensors and discuss future trends and perspectives of these sensors in biomedical research.

Study of the liquid water luminescence induced by charged particles

International Nuclear Information System (INIS)

Rusu, Mircea; Stere, Oana; Haiduc, Maria; Caramete, Laurentiu

2004-01-01

Many observations suggested that liquid water (with impurities) could give a luminescence output when irradiated with charged particles. We investigate theoretical and practical possibility of detecting such luminescence. Preliminary results on this possibility are presented, and a layout of the device proposed for measuring luminescence is given. (authors)

The nature of unusual luminescence in natural calcite, CaCO3

Energy Technology Data Exchange (ETDEWEB)

Gaft, M.; Nagli, L.; Panczer, G.; Waychunas, G.; Porat, N.

2008-11-01

The unusual luminescence of particular varieties of natural pink calcite (CaCO{sub 3}) samples was studied by laser-induced time-resolved luminescence spectroscopy at different temperatures. The luminescence is characterized by intense blue emission under short-wave UV lamp excitation with an extremely long decay time, accompanied by pink-orange luminescence under long wave UV excitation. Our investigation included optical absorption, natural thermostimulated luminescence (NTL) and Laser-Induced Breakdown Spectroscopy (LIBS) studies. Two luminescence centers were detected: a narrow violet band, with {lambda}{sub max} = 412 nm, {Delta} = 45 nm, two decay components of {tau}{sub 1} = 5 ns and {tau}{sub 2} = 7.2 ms, accompanied by very long afterglow, and an orange emission band with {lambda}{sub max} = 595 nm, {Delta} = 90 nm and {tau} = 5 ns. Both luminescence centers are thermally unstable with the blue emission disappearing after heating at 500 C, and the orange emission disappearing after heating at different temperatures starting from 230 C, although sometimes it is stable up to 500 C in different samples. Both centers have spectral-kinetic properties very unusual for mineral luminescence, which in combination with extremely low impurity concentrations, prevent their identification with specific impurity related emission. The most likely explanation of these observations may be the presence of radiation-induced luminescence centers. The long violet afterglow is evidently connected with trapped charge carrier liberation, with their subsequent migration through the valence band and ultimate recombination with a radiation-induced center responsible for the unusual violet luminescence.

Analysis of green luminescent Tb3+:Ca4GdO(BO3)3 powder phosphor

International Nuclear Information System (INIS)

Vengala Rao, B.; Rambabu, U.; Buddhudu, S.

2007-01-01

This paper reports on the emission analysis of a green luminescent Tb 3+ :Ca 4 GdO(BO 3 ) 3 powder phosphor based on the measurements of excitation, emission and lifetimes. Besides this, we have also observed an intense green emission from this powder phosphor under an UV source. The emission transitions of ( 5 D 4 →7 F 3,4,5,6 ) with λ exci =257 nm have been measured. Particularly, the green emission transition ( 5 D 4 →7 F 5 ) at 553 nm has been found to be more prominent and intense. Such green strong emission displaying powder phosphor will find applications in the development of coated screens in certain electronic systems. Apart from the emission analysis of this phosphor, XRD, SEM and FTIR studies have also been carried out in order to understand the structural details of it

Flight testing of a luminescent surface pressure sensor

Science.gov (United States)

Mclachlan, B. G.; Bell, J. H.; Espina, J.; Gallery, J.; Gouterman, M.; Demandante, C. G. N.; Bjarke, L.

1992-01-01

NASA ARC has conducted flight tests of a new type of aerodynamic pressure sensor based on a luminescent surface coating. Flights were conducted at the NASA ARC-Dryden Flight Research Facility. The luminescent pressure sensor is based on a surface coating which, when illuminated with ultraviolet light, emits visible light with an intensity dependent on the local air pressure on the surface. This technique makes it possible to obtain pressure data over the entire surface of an aircraft, as opposed to conventional instrumentation, which can only make measurements at pre-selected points. The objective of the flight tests was to evaluate the effectiveness and practicality of a luminescent pressure sensor in the actual flight environment. A luminescent pressure sensor was installed on a fin, the Flight Test Fixture (FTF), that is attached to the underside of an F-104 aircraft. The response of one particular surface coating was evaluated at low supersonic Mach numbers (M = 1.0-1.6) in order to provide an initial estimate of the sensor's capabilities. This memo describes the test approach, the techniques used, and the pressure sensor's behavior under flight conditions. A direct comparison between data provided by the luminescent pressure sensor and that produced by conventional pressure instrumentation shows that the luminescent sensor can provide quantitative data under flight conditions. However, the test results also show that the sensor has a number of limitations which must be addressed if this technique is to prove useful in the flight environment.

Recent Advances on Luminescent Enhancement-Based Porous Silicon Biosensors.

Science.gov (United States)

Jenie, S N Aisyiyah; Plush, Sally E; Voelcker, Nicolas H

2016-10-01

Luminescence-based detection paradigms have key advantages over other optical platforms such as absorbance, reflectance or interferometric based detection. However, autofluorescence, low quantum yield and lack of photostability of the fluorophore or emitting molecule are still performance-limiting factors. Recent research has shown the need for enhanced luminescence-based detection to overcome these drawbacks while at the same time improving the sensitivity, selectivity and reducing the detection limits of optical sensors and biosensors. Nanostructures have been reported to significantly improve the spectral properties of the emitting molecules. These structures offer unique electrical, optic and magnetic properties which may be used to tailor the surrounding electrical field of the emitter. Here, the main principles behind luminescence and luminescence enhancement-based detections are reviewed, with an emphasis on europium complexes as the emitting molecule. An overview of the optical porous silicon microcavity (pSiMC) as a biosensing platform and recent proof-of-concept examples on enhanced luminescence-based detection using pSiMCs are provided and discussed.

Evaluation of real-time data obtained from gravimetric preparation of antineoplastic agents shows medication errors with possible critical therapeutic impact: Results of a large-scale, multicentre, multinational, retrospective study.

Science.gov (United States)

Terkola, R; Czejka, M; Bérubé, J

2017-08-01

Medication errors are a significant cause of morbidity and mortality especially with antineoplastic drugs, owing to their narrow therapeutic index. Gravimetric workflow software systems have the potential to reduce volumetric errors during intravenous antineoplastic drug preparation which may occur when verification is reliant on visual inspection. Our aim was to detect medication errors with possible critical therapeutic impact as determined by the rate of prevented medication errors in chemotherapy compounding after implementation of gravimetric measurement. A large-scale, retrospective analysis of data was carried out, related to medication errors identified during preparation of antineoplastic drugs in 10 pharmacy services ("centres") in five European countries following the introduction of an intravenous workflow software gravimetric system. Errors were defined as errors in dose volumes outside tolerance levels, identified during weighing stages of preparation of chemotherapy solutions which would not otherwise have been detected by conventional visual inspection. The gravimetric system detected that 7.89% of the 759 060 doses of antineoplastic drugs prepared at participating centres between July 2011 and October 2015 had error levels outside the accepted tolerance range set by individual centres, and prevented these doses from reaching patients. The proportion of antineoplastic preparations with deviations >10% ranged from 0.49% to 5.04% across sites, with a mean of 2.25%. The proportion of preparations with deviations >20% ranged from 0.21% to 1.27% across sites, with a mean of 0.71%. There was considerable variation in error levels for different antineoplastic agents. Introduction of a gravimetric preparation system for antineoplastic agents detected and prevented dosing errors which would not have been recognized with traditional methods and could have resulted in toxicity or suboptimal therapeutic outcomes for patients undergoing anticancer treatment. �

X-ray luminescent glasses

International Nuclear Information System (INIS)

Takahashi, T.; Yamada, O.

1981-01-01

X-ray luminescent glasses comprising a divalent cation such as an alkaline earth metal or other divalent cations such as pb, cd, or zn, and certain rare earth metaphosphates are suitable as vitreous, x-ray phosphors or x-ray luminescent glass fibers in an x-ray intensifying screen. The glasses have the composition n(Mo X p2o5)((1-y)tb2o3 X yce2o3 X 3p2o5) wherein N is greater than zero but less than or equal to 16, M is an alkaline earth metal or other divalent cation such as pb, cd, or zn, and Y is greater than or equal to zero but less than one

Fabrication and Spectral Properties of Wood-Based Luminescent Nanocomposites

Directory of Open Access Journals (Sweden)

Xianjun Li

2014-01-01

Full Text Available Pressure impregnation pretreatment is a conventional method to fabricate wood-based nanocomposites. In this paper, the wood-based luminescent nanocomposites were fabricated with the method and its spectral properties were investigated. The results show that it is feasible to fabricate wood-based luminescent nanocomposites using microwave modified wood and nanophosphor powders. The luminescent strength is in positive correlation with the amount of phosphor powders dispersed in urea-formaldehyde resin. Phosphors absorb UV and blue light efficiently in the range of 400–470 nm and show a broad band of bluish-green emission centered at 500 nm, which makes them good candidates for potential blue-green luminescent materials.

Determination of plutonium in pure plutonium nitrate solutions - Gravimetric method

International Nuclear Information System (INIS)

1987-01-01

This International Standard specifies a precise and accurate gravimetric method for determining the concentration of plutonium in pure plutonium nitrate solutions and reference solutions, containing between 100 and 300 g of plutonium per litre, in a nitric acid medium. The weighed portion of the plutonium nitrate is treated with sulfuric acid and evaporated to dryness. The plutonium sulfate is decomposed and formed to oxide by heating in air. The oxide is ignited in air at 1200 to 1250 deg. C and weighed as stoichiometric plutonium dioxide, which is stable and non-hygroscopic

K2SO4 and LiKSO4 crystals luminescence

International Nuclear Information System (INIS)

Charapiev, B.; Nurakhmetov, T.N.

2002-01-01

In the paper a nature of X-ray and tunnel luminescence in LiKSO 4 and Li 2 SO 4 ·H 2 O crystals are discussed. It is shown, that X-ray luminescence and Li 2 SO 4 ·H 2 O and LiKSO 4 appeals in the result of electrons recombination with auto-localized holes (SO 4 - ), and tunnel luminescence appeals at electrons transfer from ground state of electron center into hole center capture ground state. Under heating of irradiated crystal de-localized holes at recombination moment with electron capture centers are forming auto-localized excitons, which are disintegrating with photon emitting, and so X-ray luminescence spectrum and thermally induces luminescence peaks are coinciding. Nature of radiation appealing in LiKSO 4 at ultraviolet excitation is discussing

Time-resolved luminescence from quartz: An overview of contemporary developments and applications

Energy Technology Data Exchange (ETDEWEB)

Chithambo, M.L., E-mail: m.chithambo@ru.ac.za [Department of Physics and Electronics, Rhodes University, PO BOX 94, Grahamstown 6140 (South Africa); Ankjærgaard, C. [Soil Geography and Landscape Group, Wageningen University Netherlands Centre for Luminescence Dating, Droevendaalsesteeg 3, 6708 PB Wageningen, The Netherlands (Netherlands); Pagonis, V. [McDaniel College, Physics Department, Westminster, MD 21157 (United States)

2016-01-15

Time-resolved optical stimulation of luminescence has become established as a key method for measurement of optically stimulated luminescence from quartz, feldspar and α-Al{sub 2}O{sub 3}:C, all materials of interest in dosimetry. The aim of time-resolved optical stimulation is to separate in time the stimulation and emission of luminescence. The luminescence is stimulated from a sample using a brief light pulse and the emission monitored during stimulation in the presence of scattered stimulating light or after pulsing, over photomultiplier noise only. Although the use of the method in retrospective dosimetry has been somewhat limited, the technique has been successfully applied to study mechanisms in the processes leading up to luminescence emission. The main means for this has been the temperature dependence of the luminescence intensity as well as the luminescence lifetimes determined from time-resolved luminescence spectra. In this paper we review some key developments in theory and applications to quartz including methods of evaluating lifetimes, techniques of evaluating kinetic parameters using both the dependence of luminescence intensity and lifetime on measurement temperature, and of lifetimes on annealing temperature. We then provide an overview of some notable applications such as separation of quartz signals from a quartz–feldspar admixture and the utility of the dynamic throughput, a measure of luminescence measured as a function of the pulse width. The paper concludes with some suggestions of areas where further exploration would advance understanding of dynamics of luminescence in quartz and help address some outstanding problems in its application.

Luminescence properties of some food dye-stuffs

International Nuclear Information System (INIS)

Astanov, S.Kh.; Muminova, Z.A.; Urunov, R.G.

2004-01-01

The luminescence properties of the natural food dye-stuffs and vitamins in temperature range of 300-5.2 K are studied. On the basis of experimental data on quantum yields of the fluorescence, trans-cis-isomerization and luminescence of the molecular oxygen the main ways of the inactivation of electronic excitations in researching compounds have been defined. (author)

Method and apparatus for reducing solvent luminescence background emissions

Energy Technology Data Exchange (ETDEWEB)

Affleck, Rhett L. (Los Alamos, NM); Ambrose, W. Patrick (Los Alamos, NM); Demas, James N. (Charlottesville, VA); Goodwin, Peter M. (Jemez Springs, NM); Johnson, Mitchell E. (Pittsburgh, PA); Keller, Richard A. (Los Alamos, NM); Petty, Jeffrey T. (Los Alamos, NM); Schecker, Jay A. (Santa Fe, NM); Wu, Ming (Los Alamos, NM)

1998-01-01

The detectability of luminescent molecules in solution is enhanced by reducing the background luminescence due to impurity species also present in the solution. A light source that illuminates the solution acts to photolyze the impurities so that the impurities do not luminesce in the fluorescence band of the molecule of interest. Molecules of interest may be carried through the photolysis region in the solution or may be introduced into the solution after the photolysis region.

Offshore gravimetric and subsidence monitoring

Energy Technology Data Exchange (ETDEWEB)

Stenvold, Torkjell

2008-06-15

are discussed in Stenvold et al. (Chapter 2). A latitude dependence of the calibration scale factors of Scintrex gravimeters is shown for the first time. Chapter 5 contains the article 'Constraints on the in situ density of CO2 within the Utsira formation from time-lapse seafloor gravity measurements' by Nooner et al. (2007), published in the International Journal of Greenhouse Gas Control. In this article gravity measurements made on 30 seafloor stations above the CO2 bubble in 2002 and 2005 have been used to constrain the in-situ density of CO2 for models derived from seismic. The gravity responses of various numerical models are compared for the1999 to 2001 period. Note that time-lapse seismic for the 2002-2005 period was not available when this article was written. Chapter 6 contains the article 'Monitoring both gas production and CO2 injection at the Sleipner field using time-lapse gravimetry' by Alnes et al., submitted 29 February 2008 to Geophysics. This is a renewed analysis of the same gravity data as in the article by Nooner et al. (Chapter 5). Recently available 4D seismic, a more updated reservoir simulation model, and reprocessed gravity and pressure data give a new estimate of CO2 density. The observed gravity response between 2002 and 2005 from the underlying Ty Formation is shown for the first time. Chapter 7 contains the article 'Gravimetric monitoring of gas production from the Troll field' by Eiken et al., submitted 3 April 2008 to Geophysics. The gravity data is used to map and quantify water influx on Troll between 2002 and 2005. There is good agreement with well data and the amount of water influx agrees with material balance calculations. Chapter 8 contains the article 'Gravimetric monitoring of gas reservoir water influx' a combined flow- and gravity-modeling approach' by Stenvold et al., and was accepted for publication in January 2008 by Geophysics. It is to appear in an upcoming special section on

Experimental aspects of buoyancy correction in measuring reliable high-pressure excess adsorption isotherms using the gravimetric method

Science.gov (United States)

Nguyen, Huong Giang T.; Horn, Jarod C.; Thommes, Matthias; van Zee, Roger D.; Espinal, Laura

2017-12-01

Addressing reproducibility issues in adsorption measurements is critical to accelerating the path to discovery of new industrial adsorbents and to understanding adsorption processes. A National Institute of Standards and Technology Reference Material, RM 8852 (ammonium ZSM-5 zeolite), and two gravimetric instruments with asymmetric two-beam balances were used to measure high-pressure adsorption isotherms. This work demonstrates how common approaches to buoyancy correction, a key factor in obtaining the mass change due to surface excess gas uptake from the apparent mass change, can impact the adsorption isotherm data. Three different approaches to buoyancy correction were investigated and applied to the subcritical CO2 and supercritical N2 adsorption isotherms at 293 K. It was observed that measuring a collective volume for all balance components for the buoyancy correction (helium method) introduces an inherent bias in temperature partition when there is a temperature gradient (i.e. analysis temperature is not equal to instrument air bath temperature). We demonstrate that a blank subtraction is effective in mitigating the biases associated with temperature partitioning, instrument calibration, and the determined volumes of the balance components. In general, the manual and subtraction methods allow for better treatment of the temperature gradient during buoyancy correction. From the study, best practices specific to asymmetric two-beam balances and more general recommendations for measuring isotherms far from critical temperatures using gravimetric instruments are offered.

Ion beam induced luminescence of germano-silicate optical fiber preform

Energy Technology Data Exchange (ETDEWEB)

Jung, Hyunkyu; Kim, Jongyeol; Lee, Namho [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Kim, Youngwoong; Han, Wontaek [Gwangju Institute of Science and Technology, Gwangju (Korea, Republic of); Markovic, Nikola; Jaksic, Milko [Ruder Boskovic Institute, Zagred (Croatia)

2014-05-15

When an optical fiber is exposed to radiation, the attenuation (RIA, Radiation Induced Attenuation) in the optical fiber (OF) is increased because of the color centers which deteriorate the transmission property and generate the absorption loss. In order to understand the radiation induced defect, Ion Beam induced luminescence (IBIL) was introduced to investigate it. IBIL technique is to analyze IR/VIS/UV luminescence related to ion beam interaction with outer shell electrons involved in chemical bonds and structure defects of target atoms. So IBIL is sensitive to its chemical composition and has been used in analysis of material characterization, geological samples and cultural heritage objects. In silica material, four O atoms are surrounding one Si atom in tetrahedral coordination. In this study, the influence of Copper (Cu) and Cerium (Ce) dopants to germano silica core optical fibers were investigated under proton irradiation at RBI using Ion Beam induced luminescence (IBIL) method. To understand the radiation induced defect of optical fibers, IBIL were tested to a germano-silica core fiber under 2 MeV proton irradiation. Although a Cu or Ce dopant was not detected by IBIL technique, the relation between the amount of radiation and luminescence can be established. This experiment showed a potential technique of studying the effects and behavior of additive elements for silica core fiber. To increase the radiation resistance of optical fibers, further investigations are needed, i. e. the proper additives and its contents and an interaction mechanism between Ge-related defects and additives.

Ion beam induced luminescence of germano-silicate optical fiber preform

International Nuclear Information System (INIS)

Jung, Hyunkyu; Kim, Jongyeol; Lee, Namho; Kim, Youngwoong; Han, Wontaek; Markovic, Nikola; Jaksic, Milko

2014-01-01

When an optical fiber is exposed to radiation, the attenuation (RIA, Radiation Induced Attenuation) in the optical fiber (OF) is increased because of the color centers which deteriorate the transmission property and generate the absorption loss. In order to understand the radiation induced defect, Ion Beam induced luminescence (IBIL) was introduced to investigate it. IBIL technique is to analyze IR/VIS/UV luminescence related to ion beam interaction with outer shell electrons involved in chemical bonds and structure defects of target atoms. So IBIL is sensitive to its chemical composition and has been used in analysis of material characterization, geological samples and cultural heritage objects. In silica material, four O atoms are surrounding one Si atom in tetrahedral coordination. In this study, the influence of Copper (Cu) and Cerium (Ce) dopants to germano silica core optical fibers were investigated under proton irradiation at RBI using Ion Beam induced luminescence (IBIL) method. To understand the radiation induced defect of optical fibers, IBIL were tested to a germano-silica core fiber under 2 MeV proton irradiation. Although a Cu or Ce dopant was not detected by IBIL technique, the relation between the amount of radiation and luminescence can be established. This experiment showed a potential technique of studying the effects and behavior of additive elements for silica core fiber. To increase the radiation resistance of optical fibers, further investigations are needed, i. e. the proper additives and its contents and an interaction mechanism between Ge-related defects and additives

Study of the corrosion behavior of magnesium alloy weldings in NaCl solutions by gravimetric tests

Directory of Open Access Journals (Sweden)

Segarra, José A.

2015-09-01

Full Text Available In this article, the corrosion behavior of commercial AZ31 welded plates in aqueous chloride media was investigated by means of gravimetric techniques and Neutral Salt Spray tests (NSS. The AZ31 samples tested were welded using Gas Tugsten Arc Welding (GTAW and different filler materials. Material microstructures were investigated by optical microscopy to stablish the influence of those microstructures in the corrosion behavior. Gravimetric and NSS tests indicate that the use of more noble filler alloys for the sample welding, preventing the reduction of aluminum content in weld beads, does not imply a better corrosion behavior.En este artículo se ha investigado el comportamiento frente a la corrosión en medios acuosos salinos de chapas soldadas de aleación AZ31 mediante técnicas gravimétricas y ensayo en cámara de niebla salina. Las muestras estudiadas han sido soldadas mediante soldadura TIG (Tungsten Inert Gas y con diferentes materiales de aporte. En el estudio se ha empleado microscopía óptica para analizar la microestructura. Los ensayos de gravimetría y los ensayos de niebla salina indican que el empleo de materiales de aporte más nobles para soldar las muestras evitando la disminución del contenido en aluminio en los cordones, no implica un mejor comportamiento frente a la corrosión.

From plasmon-induced luminescence enhancement in gold nanorods to plasmon-induced luminescence turn-off: a way to control reshaping.

Science.gov (United States)

Molinaro, Céline; Marguet, Sylvie; Douillard, Ludovic; Charra, Fabrice; Fiorini-Debuisschert, Céline

2018-04-24

Two-photon luminescence (TPL) turn-off in small single gold nanorods (GNRs) exposed to increased resonant femtosecond laser excitation (800 nm wavelength, pulse energy density varying from 125 μJ cm-2 to 2.5 mJ cm-2) is investigated. The origin is shown to be a photo-induced decrease of the rod aspect ratio. This aspect ratio reduction could reasonably be assigned to gold atom diffusion away from the rod tips, where hot spots are localized. The two-photon luminescence signal can be recovered after a blue-shift of the incident excitation wavelength. No change in the excitation wavelength results in an out of resonance excitation of the rods and thus a reduced absorption, acting as feedback to stabilize the GNR shape and size. A theoretical analysis is presented evidencing limited thermal effects in the femtosecond regime for small nanoparticles, in good agreement with complementary topographic characterizations using scanning electron microscopy (SEM) and atomic force microscopy (AFM). We show finally that TPL reveals itself as a highly sensitive tool to follow tiny changes resulting from the photo-induced reshaping of GNRs.

Luminescent materials and their applications

CERN Document Server

Virk, Hardev Singh

2015-01-01

It is pertinent to note that Luminescence phenomenon has once again occupied a central stage with the announcement of Nobel Prize in October 2014 to three Japanese scientists. The discovery of Galium Nitride proved to be a revolutionary step forward in creation of Blue LEDs. With the advent of LED lamps we now have more long-lasting and more efficient alternatives to older light sources. The Volume under reference consists of 9 Chapters, written by experts in the area of Luminescent Materials. First 5 Chapters are contributed as Review Papers and the last 4 are based on Research Papers.Chapter

Cerium luminescence in nd0 perovskites

International Nuclear Information System (INIS)

Setlur, A.A.; Happek, U.

2010-01-01

The luminescence of Ce 3+ in perovskite (ABO 3 ) hosts with nd 0 B-site cations, specifically Ca(Hf,Zr)O 3 and (La,Gd)ScO 3 , is investigated in this report. The energy position of the Ce 3+ excitation and emission bands in these perovskites is compared to those of typical Al 3+ perovskites; we find a Ce 3+ 5d 1 centroid shift and Stokes shift that are larger versus the corresponding values for the Al 3+ perovskites. It is also shown that Ce 3+ luminescence quenching is due to Ce 3+ photoionization. The comparison between these perovskites shows reasonable correlations between Ce 3+ luminescence quenching, the energy position of the Ce 3+ 5d 1 excited state with respect to the host conduction band, and the host composition. - Graphical abstract: Ce 3+ decay times versus temperature for perovskites with nd 0 B-site cations.

Luminescence properties of tetravalent uranium in aqueous solution

International Nuclear Information System (INIS)

Kirishima, A.; Kimura, T.; Nagaishi, R.; Tochiyama, O.

2004-01-01

The luminescence spectra of U 4+ in aqueous solutions were observed in the UV-VIS region at ambient and liquid nitrogen temperatures. The excitation spectrum indicates that the luminescence is arising from the deexcitation of a 5f electron at the 1 S 0 level and no other emissions of U 4+ in aqueous solutions were detected for other f-f transitions. All the luminescence peaks were assigned to the transitions from 1 S 0 to lower 5f levels. To estimate the luminescence lifetime, luminescence decay curves were measured using time-resolved laser-induced fluorescence spectroscopy. At room temperature, the decay curve indicated that the lifetime was shorter than 20 ns. On the other hand, the frozen sample of U 4+ in aqueous solution at liquid nitrogen temperature showed the same emission spectrum as at room temperature and its lifetime was 149 ns in H 2 O system and 198 ns in D 2 O system. The longer lifetime at liquid nitrogen temperature made it possible to measure the spectrum of U 4+ at the concentration as low as 10 -6 M. The difference in the anion species (ClO 4 - , Cl - , SO 4 2- ) affected the structure of the emission spectrum to some extent. (orig.)

Nanostructured Ag-zeolite Composites as Luminescence-based Humidity Sensors

Science.gov (United States)

Dieu, Bjorn; Roeffaers, Maarten B.J.; Hofkens, Johan

2016-01-01

Small silver clusters confined inside zeolite matrices have recently emerged as a novel type of highly luminescent materials. Their emission has high external quantum efficiencies (EQE) and spans the whole visible spectrum. It has been recently reported that the UV excited luminescence of partially Li-exchanged sodium Linde type A zeolites [LTA(Na)] containing luminescent silver clusters can be controlled by adjusting the water content of the zeolite. These samples showed a dynamic change in their emission color from blue to green and yellow upon an increase of the hydration level of the zeolite, showing the great potential that these materials can have as luminescence-based humidity sensors at the macro and micro scale. Here, we describe the detailed procedure to fabricate a humidity sensor prototype using silver-exchanged zeolite composites. The sensor is produced by suspending the luminescent Ag-zeolites in an aqueous solution of polyethylenimine (PEI) to subsequently deposit a film of the material onto a quartz plate. The coated plate is subjected to several hydration/dehydration cycles to show the functionality of the sensing film. PMID:27911397

[Synthesis of reserve polyhydroxyalkanoates by luminescent bacteria].

Science.gov (United States)

Boiandin, A N; Kalacheva, G S; Rodicheva, E K; Volova, T G

2008-01-01

The ability of marine luminescent bacteria to synthesize polyesters of hydroxycarboxylic acids (polyhydroxyalkanoates, PHA) as reserve macromolecules was studied. Twenty strains from the collection of the luminescent bacteria CCIBSO (WDSM839) of the Institute of Biophysics, Siberian Branch, Russian Academy of Sciences, assigned to different taxa (Photobacterium leiognathi, Ph. phosphoreum, Vibrio harveyi, and V. fischeri) were analyzed. The most productive strains were identified, and the conditions ensuring high polymer yields in batch culture (40-70% of the cell dry mass weight) were determined. The capacity of synthesizing two- and three-component polymers containing hydroxybutyric acid as the main monomer and hydroxyvaleric and hydroxyhexanoic acids was revealed in Ph. leiognathi and V. harveyi strains. The results allow luminescent microorganisms to be regarded as new producers of multicomponent polyhydroxyalkanoates.

Comparison Of Metal Corrosion Inhibition By Gravimetric And Linear Polarization Resistance Methods

OpenAIRE

Banerji, Shankha

1992-01-01

Studies were conducted to evaluate the effectiveness of various dosages of the selected silicate and phosphate compounds applied for corrosion inhibition of cast iron, copper, lead, and galvanized steel specimens. The compounds selected for study were zinc polyphosphate (Calgon C-39), zinc orthophosphate (Virchem V-931), sodium metasilicate and glassy silicate. The effectiveness of these compounds for corrosion inhibition were studied under differing water quality conditions using gravimetric...

Influence of Nanosized Silicon Oxide on the Luminescent Properties of ZnO Nanoparticles

Directory of Open Access Journals (Sweden)

Vitaliy Shvalagin

2016-01-01

Full Text Available For practical use of nanosized zinc oxide as the phosphor its luminescence quantum yields should be maximized. The aim of this work was to enhance luminescent properties of ZnO nanoparticles and obtain high-luminescent ZnO/SiO2 composites using simpler approaches to colloidal synthesis. The luminescence intensity of zinc oxide nanoparticles was increased about 3 times by addition of silica nanocrystals to the source solutions during the synthesis of ZnO nanoparticles. Then the quantum yield of luminescence of the obtained ZnO/SiO2 composites is more than 30%. Such an impact of silica is suggested to be caused by the distribution of ZnO nanocrystals on the surface of silica, which reduces the probability of separation of photogenerated charges between the zinc oxide nanoparticles of different sizes, and as a consequence, there is a significant increase of the luminescence intensity of ZnO nanoparticles. This way of increasing nano-ZnO luminescence intensity facilitates its use in a variety of devices, including optical ultraviolet and visible screens, luminescent markers, antibacterial coatings, luminescent solar concentrators, luminescent inks for security printing, and food packaging with abilities of informing consumers about the quality and safety of the packaged product.

On the correlation between annealing and variabilities in pulsed-luminescence from quartz

International Nuclear Information System (INIS)

Chithambo, M.L.

2006-01-01

Properties of luminescence lifetimes in quartz related to annealing between 500 and 900 deg. C have been investigated. The luminescence was pulse-stimulated at 470nm from sets of granular quartz annealed at 500, 600, 700, 800, and 900 deg. C. The lifetimes decrease with annealing temperature from about 42 to 33μs when the annealing temperature is increased from 500 to 900 deg. C. Luminescence lifetimes are most sensitive to duration of annealing at 600 deg. C, decreasing from 40.2+/-0.7μs by as much as 7μs when the duration of annealing is changed from 10 to 60min. However, at 800-900 deg. C lifetimes are essentially independent of annealing temperature at about 33μs. Increasing the exciting beta dose causes an increase in the lifetimes of the stimulated luminescence in the sample annealed at 800 deg. C but not in those annealed at either 500 or 600 deg. C. The temperature-resolved distribution of luminescence lifetimes is affected by thermal quenching of luminescence. These features may be accounted for with reference to two principal luminescence centres involved in the luminescence emission process

Luminescence characteristics of dental ceramics for retrospective dosimetry: a preliminary study

International Nuclear Information System (INIS)

Bailiff, I.K.; Correcher, V.; Delgado, A.; Goksu, Y.; Huebner, S.

2002-01-01

Ceramic materials that are widely employed in dental prosthetics and repairs exhibit luminescent properties. Because of their use in the body, these materials are potentially of interest in situations where retrospective dosimetry for individuals is required but where monitoring was not planned. The luminescent properties of dental ceramics obtained in Germany, Spain and the UK were examined. Linear dose-response characteristics were obtained in the range <100 mGy to 10 Gy using thermoluminescence (TL), optically stimulated luminescence and infrared-stimulated luminescence measurement techniques. Measurements of time-resolved luminescence were also performed to examine the nature of the luminescence recombination under visible (470 nm) and IR (855 nm) stimulation. The results obtained by TL and optically stimulated techniques suggest that there may be deeper traps than previously observed in certain types of dental ceramic. Such traps may be less susceptible to optical and athermal fading than was reported in earlier studies. (author)

Luminescence dating at Rose cottage cave: a progress report

CSIR Research Space (South Africa)

Woodborne, S

1997-10-01

Full Text Available Deal with infrared-stimulated luminescence and thermoluminescence dates from Rose Cottage Cave in South Africa. Discrepancy between luminescence and radiocarbon dates; Concentration of radioactive elements in sediments before and after leaching...

Luminescence basic concepts, applications and instrumentation

CERN Document Server

Virk, Hardev Singh

2014-01-01

The word luminescence was first used by a German physicist, Eilhardt Wiedemann, in 1888. He also classified luminescence into six kinds according to the method of excitation. No better basis of classification is available today. He recognized photoluminescence, thermoluminescence, electroluminescence, crystalloluminescence, triboluminescence, and chemiluminescence. The designations are obvious, characterized by the prefix. This Volume consists of 9 Chapters, including 8 Review Papers and one Case Study. The first two papers are based on OLEDs. Organic light emitting diodes (OLEDs) have been th

Defect-Induced Luminescence of a Self-Activated Borophosphate Phosphor

Science.gov (United States)

Han, Bing; Liu, Beibei; Dai, Yazhou; Zhang, Jie

2018-05-01

A self-activated borophosphate phosphor Ba3BPO7 was prepared via typical solid-state reaction in thermal-carbon reduction atmosphere. The structural and luminescence properties were investigated using x-ray powder diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, and photoluminescence spectroscopy. Upon excitation with ultraviolet (UV) light, the as-prepared phosphor shows bright greenish-yellow emission with a microsecond-level fluorescence lifetime, which could result from the oxygen vacancies produced in the process of solid-state synthesis. The possible luminescence mechanism is proposed. Through the introduction of defects in the host, this work realizes visible luminescence in a pure borophosphate compound that does not contain any rare earth or transition metal activators, so it is helpful to develop defect-related luminescent materials in view of energy conservation and environmental protection for sustainable development.

Luminescent properties of terbium complex with phenylanthranilic acid

International Nuclear Information System (INIS)

Alakaeva, L.A.; Kalazhokova, I.A.; Naurzhanova, F.Kh.

1990-01-01

Existence of terbium luminescence reaction in complex with phenanthranilic acid (FAA) is ascertained. The optimal conditions of terbium complexing with FAA are found. The ratio of components in the complex is 1:1. The influence of foreign rare earth in terbium luminescence intensity in complex with FAA is studied

Doped luminescent materials and particle discrimination using same

Science.gov (United States)

Doty, F. Patrick; Allendorf, Mark D; Feng, Patrick L

2014-10-07

Doped luminescent materials are provided for converting excited triplet states to radiative hybrid states. The doped materials may be used to conduct pulse shape discrimination (PSD) using luminescence generated by harvested excited triplet states. The doped materials may also be used to detect particles using spectral shape discrimination (SSD).

Signal intensity analysis and optimization for in vivo imaging of Cherenkov and excited luminescence

Science.gov (United States)

LaRochelle, Ethan P. M.; Shell, Jennifer R.; Gunn, Jason R.; Davis, Scott C.; Pogue, Brian W.

2018-04-01

During external beam radiotherapy (EBRT), in vivo Cherenkov optical emissions can be used as a dosimetry tool or to excite luminescence, termed Cherenkov-excited luminescence (CEL) with microsecond-level time-gated cameras. The goal of this work was to develop a complete theoretical foundation for the detectable signal strength, in order to provide guidance on optimization of the limits of detection and how to optimize near real time imaging. The key parameters affecting photon production, propagation and detection were considered and experimental validation with both tissue phantoms and a murine model are shown. Both the theoretical analysis and experimental data indicate that the detection level is near a single photon-per-pixel for the detection geometry and frame rates commonly used, with the strongest factor being the signal decrease with the square of distance from tissue to camera. Experimental data demonstrates how the SNR improves with increasing integration time, but only up to the point where the dominance of camera read noise is overcome by stray photon noise that cannot be suppressed. For the current camera in a fixed geometry, the signal to background ratio limits the detection of light signals, and the observed in vivo Cherenkov emission is on the order of 100×  stronger than CEL signals. As a result, imaging signals from depths  <15 mm is reasonable for Cherenkov light, and depths  <3 mm is reasonable for CEL imaging. The current investigation modeled Cherenkov and CEL imaging of two oxygen sensing phosphorescent compounds, but the modularity of the code allows for easy comparison of different agents or alternative cameras, geometries or tissues.

Efficient and thermally stable red luminescence from nano-sized phosphor of Gd6MoO12:Eu3+

International Nuclear Information System (INIS)

Qin, Lin; Wei, Donglei; Huang, Yanlin; Kim, Sun Il; Yu, Young Moon; Seo, Hyo Jin

2013-01-01

A novel red-emitting nano-phosphor of Eu 3+ -doped Gd 6 MoO 12 was successfully synthesized by the Pechini method. The crystalline phase was confirmed by X-ray powder diffraction analysis. The morphology of the nano-phosphor was analyzed by scanning electron microscopy, indicating a good crystallization with particles smaller than 500 nm. The luminescence properties such as photoluminescence spectra and decay curves were investigated. The phosphors can be efficiently excited by near-ultraviolet (near-UV) light and exhibit a bright red luminescence around 613 nm ascribed to the forced electric dipole transition 5 D 0 → 7 F 2 of Eu 3+ ions. The thermal stabilities were investigated from the temperature-dependent luminescence decay curves (lifetimes) and spectra intensities. The luminescence properties in relation to applications in white light-emitting diodes (W-LEDs) such as the absolute luminescence quantum efficiency, excitation wavelength, and color coordinates were discussed. The Gd 6 MoO 12 :Eu 3+ nano-phosphor is a promising red-emitting candidate for the fabrication of W-LEDs with near-UV chips

Polarization memory of white luminescence of Ag nanoclusters dispersed in glass host.

Science.gov (United States)

Kuznetsov, A S; Tikhomirov, V K; Moshchalkov, V V

2012-09-10

A mechanism for white luminescence of Ag nanoclusters dispersed in oxyfluoride glass host has been revealed by studying a temperature dependence of its polarization memory. The spectral dependence of the polarization memory indicates the presence of a variety of Ag nanoclusters, particularly emitting in the blue, green and red. Temperature activated intercluster energy transfer has been found responsible for white luminescence. The means for increasing luminescence quantum yield have been suggested. This efficient white luminescence may be used in highly demanded devices, such as luminescent lamps, displays, color phosphors for LEDs, photovoltaic devices based on down shifting of solar spectrum.

Photometrically measured continuous personal PM(2.5) exposure: levels and correlation to a gravimetric method.

Science.gov (United States)

Lanki, Timo; Alm, Sari; Ruuskanen, Juhani; Janssen, Nicole A H; Jantunen, Matti; Pekkanen, Juha

2002-05-01

There is evidence that hourly variations in exposure to airborne particulate matter (PM) may be associated with adverse health effects. Still there are only few published data on short-term levels of personal exposure to PM in community settings. The objectives of the study were to assess hourly and shorter-term variations in personal PM(2.5) exposure in Helsinki, Finland, and to compare results from portable photometers to simultaneously measured gravimetric concentrations. The effect of relative humidity on the photometric results was also evaluated. Personal PM(2.5) exposures of elderly persons were assessed for 24 h every second week, resulting in 308 successful measurements from 47 different subjects. Large changes in concentrations in minutes after cooking or changing microenvironment were seen. The median of daily 1-h maxima was over twice the median of 24-h averages. There was a strong significant association between the two means, which was not linear. Median (95th percentile) of the photometric 24-h concentrations was 12.1 (37.7) and of the 24-h gravimetric concentrations 9.2 (21.3) microg/m3. The correlation between the photometric and the gravimetric method was quite good (R2=0.86). Participants spent 94.1% of their time indoors or in a vehicle, where relative humidity is usually low and thus not likely to cause significant effects on photometric results. Even outdoors, the relative humidity had only modest effect on concentrations. Photometers are a promising method to explore the health effects of short-term variation in personal PM(2.5) exposure.

Soft X-ray excited optical luminescence from functional organic materials

Energy Technology Data Exchange (ETDEWEB)

Sham, T.K., E-mail: tsham@uwo.ca

2015-10-01

Highlights: • Many functional organic materials convert X-ray energy into visible light. • The X-ray induced luminescence (XEOL) across an absorption edge can be site and excitation channel specific. • XEOL is composition, morphology, size and crystallinity dependent. • XEOL using the time structure of a synchrotron can reveal the decay and energy transfer dynamics of the sample. • The combined use of XEOL and XAS in the analysis of functional organic materials is illustrated. - Abstract: This brief report reviews some of the recent findings in the study of synchrotron based X-ray excited optical luminescence (XEOL) from representative organic light emitting device (OLED) and related functional organic materials. The systems of interest include Alq{sub 3}, aluminium tris(8-hydroxylquinoline); Ru(bipy){sub 3}{sup 2+}, tris-(2,2-bipyridine) ruthenium(II); Ir(bpy){sub 3}, tris(2-phenyl-bipyridine)iridium; PVK (poly(N-vinylcarbazole)) and [Au{sub 2}(dppe)(bipy)]{sup 2+}, a Au(I) polymer containing 1,2-bis(diphenylphosphino)ethane and the 4,40-bipyridyl ligands, as well as TBPe (2,5,8,11-tetra-tert-butylperylene) polyhedral crystals and fluorescein isothiocyanate (FITC) and FITC-labelled proteins. It is shown that tunable and pulsed X-rays from synchrotron light sources enable the detailed tracking of the optical properties of organic functional materials by monitoring the luminescence in both the energy and time domain as the excitation energy is scanned across an element-specific absorption edge. The use of XEOL and X-ray absorption spectroscopy (XAS) in materials analysis is illustrated.

A new and simple gravimetric method for determination of uranium

International Nuclear Information System (INIS)

Saxena, A.K.

1994-01-01

A new and simple gravimetric method for determining uranium has been described. Using a known quantity of uranyl nitrate as the test solution, an alcoholic solution of 2-amino-2-methyl 1:3 propanediol (AMP) was added slowly. A yellow precipitate was obtained which was filtered through ashless filter paper, washed with alcohol, dried and ignited at 800 degC for 4h. It gave a black powder as a product which was shown by X-ray diffraction to be U 3 O 8 . The percentage error was found in the range -0.09 to +0.89. (author). 8 refs., 1 tab

Luminescence and photosensitivity of PbI2 crystals

International Nuclear Information System (INIS)

Novosad, S.S.; Novosad, I.S.; Matviishin, I.M.

2002-01-01

One studied effect of temperature treatment and storage conditions on spectra features of PbI 2 crystals grown by the Bridgman-Stockbarger method from salt additionally purified by directed crystallization. Spectra of X-ray luminescence, photoluminescence and thermostimulated luminescence were investigated within 85-295 K temperature range under stationary X-ray excitation and emission of N 2 -laser. One studied photoelectret properties of those crystals under 85 K. Luminescence of PbI 2 crystals with maximum within 595 nm region observed following their thermal annealing under 475-495 K temperature and typical for near-the-surface section of specimens may be caused by oxygen-containing centres [ru

A luminescence imaging system based on a CCD camera

DEFF Research Database (Denmark)

Duller, G.A.T.; Bøtter-Jensen, L.; Markey, B.G.

1997-01-01

Stimulated luminescence arising from naturally occurring minerals is likely to be spatially heterogeneous. Standard luminescence detection systems are unable to resolve this variability. Several research groups have attempted to use imaging photon detectors, or image intensifiers linked...... to photographic systems, in order to obtain spatially resolved data. However, the former option is extremely expensive and it is difficult to obtain quantitative data from the latter. This paper describes the use of a CCD camera for imaging both thermoluminescence and optically stimulated luminescence. The system...

Luminescent microporous metal–organic framework with functional Lewis basic sites on the pore surface: Quantifiable evaluation of luminescent sensing mechanisms towards Fe{sup 3+}

Energy Technology Data Exchange (ETDEWEB)

Jin, Jun-Cheng [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the Ministry of Education, Shaanxi Key Laboratory of Physico-Inorganic Chemistry, College of Chemistry & Materials Science, Northwest University, Xi' an 710069 (China); Technology Promotion Center of Nano Composite Material of Biomimetic Sensor and Detecting Technology, Preparation and Application, Anhui Provincial Laboratory West Anhui University, Anhui 237012 (China); Guo, Rui-Li; Zhang, Wen-Yan [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the Ministry of Education, Shaanxi Key Laboratory of Physico-Inorganic Chemistry, College of Chemistry & Materials Science, Northwest University, Xi' an 710069 (China); Jiang, Chen [Technology Promotion Center of Nano Composite Material of Biomimetic Sensor and Detecting Technology, Preparation and Application, Anhui Provincial Laboratory West Anhui University, Anhui 237012 (China); Wang, Yao-Yu, E-mail: wyaoyu@nwu.edu.cn [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the Ministry of Education, Shaanxi Key Laboratory of Physico-Inorganic Chemistry, College of Chemistry & Materials Science, Northwest University, Xi' an 710069 (China)

2016-11-15

A systematic study has been conducted on a novel luminescent metal-organic framework, ([Zn(bpyp)(L-OH)]·DMF·2H{sub 2}O){sub n} (1), to explore its sensing mechanisms to Fe{sup 3+}. Structure analyses show that compound 1 exist pyridine N atoms and -OH groups on the pore surface for specific sensing of metal ions via Lewis acid-base interactions. On this consideration, the quenching mechanisms are studied and the processes are controlled by multiple mechanisms in which dynamic and static mechanisms are calculated, achieving the quantification evaluation of the quenching process. This work not only achieves the quantitative evaluation of the luminescence quenching but also provides certain insights into the quenching process, and the possible mechanisms explored in this work may inspire future research and design of target luminescent metal-organic frameworks (LMOFs) with specific functions. - Graphical abstract: A systematic study has been conducted on a novel luminescent metal-organic framework to explore its sensing mechanisms to Fe{sup 3+}. The quenching mechanisms are studied and the processes are controlled by multiple mechanisms in which dynamic and static mechanisms are calculated, achieving the quantification evaluation of the quenching process. - Highlights: • A novel porous luminescent MOF containing uncoordinated groups in interlayer channels was successfully synthesized. • The compound 1 can exhibit significant luminescent sensitivity to Fe{sup 3+}, which make its good candidate as luminescent sensor. • The corresponding dynamic and static quenching constants are calculated, achieving the quantification evaluation of the quenching process.

Methods of producing luminescent images

International Nuclear Information System (INIS)

Broadhead, P.; Newman, G.A.

1977-01-01

A method is described for producing a luminescent image in a layer of a binding material in which is dispersed a thermoluminescent material. The layer is heated uniformly to a temperature of 80 to 300 0 C and is exposed to luminescence inducing radiation whilst so heated. The preferred exposing radiation is X-rays and preferably the thermoluminescent material is insensitive to electromagnetic radiation of wavelength longer than 300 mm. Information concerning preparation of the luminescent material is given in BP 1,347,672; this material has the advantage that at elevated temperatures it shows increased sensitivity compared with room temperature. At temperatures in the range 80 to 150 0 C the thermoluminescent material exhibits 'afterglow', allowing the image to persist for several seconds after the X-radiation has ceased, thus allowing the image to be retained for visual inspection in this temperature range. At higher temperatures, however, there is negligible 'afterglow'. The thermoluminescent layers so produced are particularly useful as fluoroscopic screens. The preferred method of heating the thermoluminescent material is described in BP 1,354,149. An example is given of the application of the method. (U.K.)

Determination of molecular structures of aromatic hydrocarbons of crystal fractions of Noriysk crude by a series of luminescent-spectral methods

Energy Technology Data Exchange (ETDEWEB)

Ogloblina, A.I.; Alekseyeva, T.A.; Barabadze, Sh.Sh.; Melikadze, L.D.; Teplitskaya, T.A.

1979-01-01

The structure of crystalline aromatic hydrocarbons isolated from the high boiling fraction (540-560 degrees) of Noriysk crude was studied using methods of luminescent-spectral analysis. The individual composition of the crystalline aromatic hydrocarbons was analyzed by a combination of fine structure luminescent spectroscopy and spectrofluorimetric methods in frozen matrices using spectra of fluorescence, phosphorescence and excitation of luminescence. The composite method used at 77 K is very effective and allows detailed characteristics of the molar-group composition of complex mixtures of petroleum aromatic hydrocarbons to the point of identification of individual components.

Spatially-resolved measurement of optically stimulated luminescence and time-resolved luminescence

International Nuclear Information System (INIS)

Bailiff, I.K.; Mikhailik, V.B.

2003-01-01

Spatially-resolved measurements of optically stimulated luminescence (OSL) were performed using a two-dimensional scanning system designed for use with planar samples. The scanning system employs a focused laser beam to stimulate a selected area of the sample, which is moved under the beam by a motorised stage. Exposure of the sample is controlled by an electronic shutter. Mapping of the distribution of OSL using a continuous wave laser source was obtained with sub-millimeter resolution for samples of sliced brick, synthetic single crystal quartz, concrete and dental ceramic. These revealed sporadic emission in the case of brick or concrete and significant spatial variation of emission for quartz and dental ceramic slices. Determinations of absorbed dose were performed for quartz grains within a slice of modern brick. Reconfiguration of the scanner with a pulsed laser source enabled quartz and feldspathic minerals within a ceramic sample to be thinner region. about 6 nm from the extrapolation of themeasuring the time-resolved luminescence spectrum

Luminescence centers in bismuth orthogermanate

International Nuclear Information System (INIS)

Bordun, O.M.

2001-01-01

The luminescence and photoexcitation spectra of single crystals,ceramics,and thin films of Bi 4 Ce 3 O 1 2 are studied.The decomposition of the luminescence spectra into elementary components by the Alentsev-Fock method showed that they consist of three bands with maxima at 2.7,2.4,and 2.05 eV.The bands with maxima at 2.7 and 2.4 eV are assigned to the emission of self-trapped Frenkel excitons describing the excited state of a (BiO 6 ) 9- molecular ion. Emission bands with maxima at 2.0 5 eV are assigned to recombination on traps caused by structural defects

Luminescence properties of Y3Al5O12:Ce nanoceramics

International Nuclear Information System (INIS)

Zorenko, Yu.; Voznyak, T.; Gorbenko, V.; Zych, E.; Nizankovski, S.; Dan'ko, A.; Puzikov, V.

2011-01-01

Comparative analysis of the luminescent properties of Y 3 Al 5 O 12 :Ce (YAG:Ce) transparent optical ceramics (OS) with those of single crystal (SC) and single crystalline film (SCF) analogues has been performed under excitation by pulsed synchrotron radiation in the fundamental absorption range of YAG host. It has been shown that the properties of YAG:Ce OC are closer to the properties of the SCF counterpart, where Y Al antisite defects are completely absent, rather than to the properties of SC of this garnet with large concentration of Y Al antisite defects. At the same time, the luminescence spectra of YAG:Ce OC show weak emission bands in the 200-470 nm range related to Y Al antisite defects and charged oxygen vacancies (F + and F centers). YAG:Ce OS also possesses significantly larger contribution of slow components in the Ce 3+ luminescence decay under high-energy excitation in comparison with SC and SCF of this garnet due to the involvement of antisite defects, charged oxygen vacancies as well as boundaries of grains in the energy transfer processes from the host to the Ce 3+ ions.

A Radiation Dosimetry Method Using Pulsed Optically Stimulated Luminescence

International Nuclear Information System (INIS)

Akselrod, M.S.; McKeever, S.W.S.

1999-01-01

A method for the determination of absorbed radiation dose is described based on pulsed optically stimulated luminescence (POSL). The method relies upon the stimulation of an irradiated sample with a train of light pulses from a suitable light source (e.g. a laser) using a wavelength which is within the range of wavelengths corresponding to the radiation-induced optical absorption in the irradiated sample. The subsequent emitted light, due to the detrapping of trapped charges and their subsequent recombination with charge of the opposite sign, is synchronously detected in the period between each stimulation pulse. The total luminescence is summed over the desired number of stimulation pulses and this forms the measured POSL signal. By monitoring the emitted light only in the period between stimulation pulses one can reduce the optical filtering required to discriminate between the stimulation light and the emission light; in this way a high measurement efficiency, and, therefore, a high radiation sensitivity (luminescence intensity per unit absorbed dose) is achieved. Key parameters in the method are the intrinsic luminescence lifetime for the material being used as the luminescent detector, the width of the optical stimulation pulse, and the period between pulses. For optimum operation the measurement parameters should be such that both the pulse width and the time between pulses are much less than the luminescence lifetime. By appropriate choice of the power of the optical stimulation, the frequency of the stimulation pulses, and the total stimulation period, one can also re-measure the absorbed dose several times. In this way, a re-read capability is available with the procedure. The method is illustrated using light from a 2nd-harmonic Nd:YAG laser, with irradiated, anion-deficient aluminium oxide as the luminescent detector material. (author)

Luminescence from cavitation bubbles deformed in uniform pressure gradients

Science.gov (United States)

Supponen, Outi; Obreschkow, Danail; Kobel, Philippe; Farhat, Mohamed

2017-09-01

Presented here are observations that demonstrate how the deformation of millimetric cavitation bubbles by a uniform pressure gradient quenches single-collapse luminescence. Our innovative measurement system captures a broad luminescence spectrum (wavelength range, 300-900 nm) from the individual collapses of laser-induced bubbles in water. By varying the bubble size, driving pressure, and perceived gravity level aboard parabolic flights, we probed the limit from aspherical to highly spherical bubble collapses. Luminescence was detected for bubbles of maximum radii within the previously uncovered range, R0=1.5 -6 mm, for laser-induced bubbles. The relative luminescence energy was found to rapidly decrease as a function of the bubble asymmetry quantified by the anisotropy parameter ζ , which is the dimensionless equivalent of the Kelvin impulse. As established previously, ζ also dictates the characteristic parameters of bubble-driven microjets. The threshold of ζ beyond which no luminescence is observed in our experiment closely coincides with the threshold where the microjets visibly pierce the bubble and drive a vapor jet during the rebound. The individual fitted blackbody temperatures range between Tlum=7000 and Tlum=11 500 K but do not show any clear trend as a function of ζ . Time-resolved measurements using a high-speed photodetector disclose multiple luminescence events at each bubble collapse. The averaged full width at half-maximum of the pulse is found to scale with R0 and to range between 10 and 20 ns.

Luminescent micro- and nanofibers based on novel europium phthalate complex

Energy Technology Data Exchange (ETDEWEB)

Enculescu, M., E-mail: mdatcu@infim.ro [National Institute of Materials Physics, Multifunctional Materials and Structures, PO Box MG-7, 77125 Magurele-Bucharest (Romania); Preda, N.; Matei, E.; Enculescu, I. [National Institute of Materials Physics, Multifunctional Materials and Structures, PO Box MG-7, 77125 Magurele-Bucharest (Romania)

2012-09-14

We synthesized by wet chemical route a novel europium-potassium phthalate complex Eu{sup 3+}K{sup +}[(COO){sub 2}(C{sub 6}H{sub 4})]{sub 2}. The compound is a white powder insoluble in water. X-ray diffraction evaluation shows that we obtained a new crystalline compound with no traces of the starting materials (potassium hydrogen phthalate and europium chloride). Scanning electron microscopy reveals that the powder consists of fiber-shaped structures with sizes larger than 250 nm in diameter. Energy dispersive X-ray analysis proves that the compound has a 1:1 europium-potassium ratio. Fourier transform infrared spectroscopy confirms the presence of the phthalate in the new compound. Photoluminescence and cathodoluminescence measurements show that the fiber-shaped structures are intensely luminescent with emission bands corresponding to the {sup 5}D{sub 0} {yields} {sup 7}F{sub J} (J = 1-4) Eu (III) ion's transitions in the region between 580 nm and 700 nm, the most intense maximum being observed around 615 nm. Up-converted luminescence with a maximum at 315 nm was recorded. -- Highlights: Black-Right-Pointing-Pointer A new europium-potassium phthalate complex was synthesized by wet chemical route. Black-Right-Pointing-Pointer Fiber-shaped crystalline structures with sizes larger than 250 nm. Black-Right-Pointing-Pointer The most probable structure of the molecule is [C{sub 6}H{sub 4}(COO{sup -}){sub 2}]{sub 2} K{sup +}Eu{sup 3+}. Black-Right-Pointing-Pointer Intense luminescence due to Eu{sup 3+} ions {sup 5}D{sub 0} {yields} {sup 7}F{sub J} transitions. Black-Right-Pointing-Pointer Up-converted luminescence with a maximum at 315 nm was recorded.

Evaluation of a reconfigurable portable instrument for copper determination based on luminescent carbon dots.

Science.gov (United States)

Salinas-Castillo, Alfonso; Morales, Diego P; Lapresta-Fernández, Alejandro; Ariza-Avidad, María; Castillo, Encarnación; Martínez-Olmos, Antonio; Palma, Alberto J; Capitan-Vallvey, Luis Fermin

2016-04-01

A portable reconfigurable platform for copper (Cu(II)) determination based on luminescent carbon dot (Cdots) quenching is described. The electronic setup consists of a light-emitting diode (LED) as the carbon dot optical exciter and a photodiode as a light-to-current converter integrated in the same instrument. Moreover, the overall analog conditioning is simply performed with one integrated solution, a field-programmable analog array (FPAA), which makes it possible to reconfigure the filter and gain stages in real time. This feature provides adaptability to use the platform as an analytical probe for carbon dots coming from different batches with some variations in luminescence characteristics. The calibration functions obtained that fit a modified Stern-Volmer equation were obtained using luminescence signals from Cdots quenching by Cu(II). The analytical applicability of the reconfigurable portable instrument for Cu(II) using Cdots has been successfully demonstrated in tap water analysis.

f-state luminescence of lanthanide and actinide ions in solution

International Nuclear Information System (INIS)

Beitz, J.V.

1993-01-01

Detailed studies of the luminescence of aquated Am 3+ are presented in the context of prior lanthanide and actinide ion work. The luminescing state of aquated Am 3+ is confirmed to be 5 D l based on observed emission and excitation spectra. The luminescence lifetime of Am 3+ in H 2 O solution is (22 ± 3) ns and (155 ± 4) ns in D 2 O solution at 295 K. Judd-Ofelt transition intensity theory qualitatively describes the observed Am 3+ relative integrated fluorescence intensities. Recent luminescence studies on complexed trivalent f-element ions in solution are reviewed as to the similarities and differences between lanthanide ion 4f state and actinide ion 5f state properties

Tectonic evolution of the Paranoá basin: New evidence from gravimetric and stratigraphic data

Science.gov (United States)

Martins-Ferreira, Marco Antonio Caçador; Campos, José Eloi Guimarães; Von Huelsen, Monica Giannoccaro

2018-06-01

Field gravimetric and stratigraphic surveys were conducted with the aim to constraint the mechanisms responsible for the initiation of the Stenian-Tonian Paranoá basin, central Brazil, a subject not yet studied in detail. The Paranoá Group crops out in the external zone of the Brasília Belt, a Neoproterozoic orogen in the western margin of the São Francisco Craton. Detailed geological mapping confirmed the existence of a regional scale fault that controlled sedimentation of the Paranoá Group during the deposition of its basal formations, revealing important details about basin initiation and early evolution. Gravimetric modeling indicates the existence of paleorift structures beneath the Paranoá sequence in the study area. Results from both stratigraphic and gravimetric surveys show strong evidence of mechanical subsidence by faulting during basin initiation. Unsorted, angular, clasts cut by quartz veins and brecciated boulders present in the basal conglomerate, support this hypothesis. Basin initiation faults coincide with deeper paleorift faults and are thus interpreted as reactivations of the older Statherian Araí Rift. The reactivations favored an initial regime of mechanical subsidence, dominated by the development of epirogenic arches subsiding at different rates. Apart from faulting activity, the post-basal sequence presents no evidence of rift environment in the strict sense. Besides, the great lateral continuity and relatively constant thickness of facies, indicate that an initial mechanic subsidence rapidly gave way to flexural subsidence during subsequent stages of basin evolution. The Paranoá Group do not present reliable characteristics that would allow its strict classification as a passive margin. Its main stratigraphic characteristics, tectonic location and basement architecture, indicate that the Paranoá Group was deposited in a cratonic margin basin, and may have been either connected to a passive margin basin at times of sea level rise

Analysis of structure origin and luminescence properties of Yb(3+)-Er(3+) co-doped fluorophosphate glass.

Science.gov (United States)

Chen, Fangze; Jing, Xufeng; Wei, Tao; Wang, Fengchao; Tian, Ying; Xu, Shiqing

2014-08-14

The near infrared luminescence properties of Yb(3+)-Er(3+) co-doped fluorophosphate glasses have been investigated. The various effects on structure and 1.53 μm emission were analyzed as a function of Yb(3+) concentration. The energy transfer mechanism was proposed. High measured lifetime (10.75 ms), large effective full widths at half maximum (73.71 nm) and large gain per unit length (62.8 × 10(-)(24)cm(2)s) have been achieved in prepared glass. The present glass co-doped with 6mol% YbF3 and 2 mol% ErF3 showed magnificent luminescence properties for telecommunication application. Copyright © 2014 Elsevier B.V. All rights reserved.

The application of time-resolved luminescence spectroscopy to a remote uranyl sensor

International Nuclear Information System (INIS)

Varineau, P.T.; Duesing, R.; Wangen, L.E.

1991-01-01

Time resolved luminescence spectroscopy is an effective method for the determination of a wide range of uranyl concentrations in aqueous samples. We have applied this technique to the development of a remote sensing device using fiber optic cables coupled with a micro flow cell in order to probe for uranyl in aqueous samples. This sensor incorporates a Nafion membrane through which UO 2 2+ can diffuse in to a reaction/analysis chamber which holds phosphoric acid, a reagent which enhances the uranyl luminescence intensity and lifetime. With this device, anionic and fluorescing organic interferences could be eliminated, allowing for the determination of uranyl over a concentration range of 10 4 to 10 -9 M. 17 refs., 5 figs

Holographic patterning of luminescent photopolymer nanocomposites

International Nuclear Information System (INIS)

Sakhno, Oksana V.; Smirnova, Tatiana N.; Goldenberg, Leonid M.; Stumpe, Joachim

2008-01-01

Volume phase gratings in the photopolymerisable composites, containing luminescent nanoparticles have been fabricated for the first time. Nanoparticles of LaPO 4 , doped by Ce 3+ and Tb 3+ ions (the trade name is REN-X-green) with high luminescence quantum yield were used as a luminescent inorganic additive. The holographic gratings in such materials are formed as a result of the diffusion distribution of the nanoparticles during exposure of photopolymerisable composites to interference pattern. The influence of the pre-polymer formulation and the holographic patterning parameters on the grating formation is comprehensively investigated. The use of the optimised pre-polymer syrup containing two monomers with sufficiently different polymerisation rates allows fabrication of gratings with diffraction efficiency up to 80% at low optical losses (< 5%) (20 μm film thickness). To obtain maximum diffraction efficiency the intensity and the period of the interference pattern were optimised for each formulation. In addition maximum diffraction efficiency was achieved with the nanocomposites containing 30-32 wt.% of nanoparticles. On the other hand the highest possible modulation of the nanoparticles' concentration was obtained for the concentration of about 20 wt.%. In this case maximum ordering of the nanoparticles in the polymer matrix is achieved. The photoluminescence of the nanoparticles within the homogeneous polymer film and within the grating has been measured. The example application of the photopolymerisable composite containing luminescence inorganic nanoparticles in holographic security technology has been demonstrated

Analyte-triggered luminescence of Eu{sup 3+} ions encapsulated in Nafion membranes -preparation of hybrid materials from in membrane chemical reactions-

Energy Technology Data Exchange (ETDEWEB)

Aguilar-Sánchez, Rocío, E-mail: raguilar@ifuap.buap.mx [Depto. Química Analítica, Facultad de Ciencias Químicas, Benemérita Universidad Autónoma de Puebla, Puebla 72570 (Mexico); Zelocualtecatl-Montiel, Iván [Depto. Química Analítica, Facultad de Ciencias Químicas, Benemérita Universidad Autónoma de Puebla, Puebla 72570 (Mexico); Gálvez-Vázquez, María de Jesús [Depto. Química Analítica, Facultad de Ciencias Químicas, Benemérita Universidad Autónoma de Puebla, Puebla 72570 (Mexico); Instituto de Física, Benemérita Universidad Autónoma de Puebla, Apartado postal J-48, Puebla 72570 (Mexico); Silva-González, Rutilo [Instituto de Física, Benemérita Universidad Autónoma de Puebla, Apartado postal J-48, Puebla 72570 (Mexico)

2017-04-15

The possibility to perform chemical reactions inside polymer materials opens a unique opportunity to control and prepare materials for diverse solid-state applications. Based on the affinity of Eu{sup 3+} ions for oxygen functionalities, in this work we report the luminescence enhancement of Eu{sup 3+} ions inserted in Nafion membranes (Naf/Eu{sup 3+}) by in-situ complexing to oxalate. The formation of a europium-oxalate type complex enhances Eu{sup 3+} luminescence emission, which could be exploited for the construction of devices for oxalate sensing and the fabrication of highly luminescent materials. Possible analytical applications of Naf/Eu{sup 3+} membranes were evaluated by fluorescence spectroscopy through the linear response with concentration. The complex formation was followed by infrared spectroscopy and SEM-EDS analysis. - Highlights: • Luminescence enhancement by complexation of Eu{sup 3+} ions to oxalate inside Nafion. • Performance of chemical reactions inside Nafion/polymer membranes. • An easy and novel method to prepare luminescent solid devices. • Possibility to develop luminescent sensors by analyte-triggered optical response.

A cost-effective technique for integrating personal radiation dose assessment with personal gravimetric sampling

International Nuclear Information System (INIS)

Strydom, R.; Rolle, R.; Van der Linde, A.

1992-01-01

During recent years there has been an increasing awareness internationally of radiation levels in the mining and milling of radioactive ores, including those from non-uranium mines. A major aspect of radiation control is concerned with the measurement of radiation levels and the assessment of radiation doses incurred by individual workers. Current techniques available internationally for personnel monitoring of radiation exposures are expensive and there is a particular need to reduce the cost of personal radiation monitoring in South African gold mines because of the large labour force employed. In this regard the obvious benefits of integrating personal radiation monitoring with existing personal monitoring systems already in place in South African gold mines should be exploited. A system which can be utilized for this purpose is personal gravimetric sampling. A new cost-effective technique for personal radiation monitoring, which can be fully integrated with the personal gravimetric sampling strategy being implemented on mines, has been developed in South Africa. The basic principles of this technique and its potential in South African mines are described. 9 refs., 7 figs

Determination of uranium in coated fuel particle compact by potassium fluoride fusion-gravimetric method

International Nuclear Information System (INIS)

Ito, Mitsuo; Iso, Shuichi; Hoshino, Akira; Suzuki, Shuichi.

1992-03-01

Potassium fluoride-gravimetric method has been developed for the determination of uranium in TRISO type-coated fuel particle compact. Graphite matrix in the fuel compact is burned off by heating it in a platinum crucible at 850degC. The coated fuel particles thus obtained are decomposed by fusion with potassium fluoride at 900degC. The melt was dissolved with sulfuric acid. Uranium is precipitated as ammonium diuranate, by passing ammonia gas through the solution. The resulting precipitate is heated in a muffle furnace at 850degC, to convert uranium into triuranium octoxide. Uranium in the triuranium octoxide was determined gravimetrically. Ten grams of caoted fuel particles were completely decomposed by fusion with 50 g of potassium fluoride at 900degC for 3 hrs. Analytical result for uranium in the fuel compact by the proposed method was 21.04 ± 0.05 g (n = 3), and was in good agreement with that obtained by non-destructive γ-ray measurement method : 21.01 ± 0.07 g (n = 3). (author)

Luminescence properties of Yb:Nd:Tm:KY{sub 3}F{sub 10} nanophosphor and thermal treatment effects

Energy Technology Data Exchange (ETDEWEB)

Gomes, Laércio, E-mail: lgomes@ipen.br [Centro de Lasers e Aplicações, Instituto de Pesquisas Energéticas e Nucleares, IPEN-CNEN/SP, Butantã, P.O. Box 11049, São Paulo, SP o5422-970 (Brazil); Linhares, Horácio Marconi da Silva M.D. [Centro de Lasers e Aplicações, Instituto de Pesquisas Energéticas e Nucleares, IPEN-CNEN/SP, Butantã, P.O. Box 11049, São Paulo, SP o5422-970 (Brazil); Ichikawa, Rodrigo Uchida; Martinez, Luis Gallego [Departamento de Ciências dos Materiais, Instituto de Pesquisas Energéticas e Nucleares (Brazil); Ranieri, Izilda Marcia [Centro de Lasers e Aplicações, Instituto de Pesquisas Energéticas e Nucleares, IPEN-CNEN/SP, Butantã, P.O. Box 11049, São Paulo, SP o5422-970 (Brazil)

2015-01-15

In this work, we present the spectroscopic properties of KY{sub 3}F{sub 10} (KY3F) nanocrystals activated with thulium and codoped with ytterbium and neodymium ions. The most important processes that lead to the thulium upconversion emissions in the blue region were identified. A time-resolved luminescence spectroscopy technique was employed to measure the luminescence decays and to determine the most important mechanisms involved in the upconversion process that populates {sup 1}G{sub 4} (Tm{sup 3+}) excited states. Analysis of the energy-transfer processes dynamics using selective pulsed-laser excitations in Yb:Nd:Tm, Nd:KY3F nanocrystals shows that the direct energy transfer from Nd{sup 3+} to Tm{sup 3+} ions is the mechanism responsible for the 78% of the blue upconversion luminescence in the Yb:Nd:Tm:KY3F when compared with the Yb:Nd:Tm:KY3F bulk crystal for an laser excitation at 802 nm. An investigation of the {sup 1}G{sub 4} level luminescence kinetic of Tm{sup 3+} in Yb/Nd/Tm system revealed that the luminescence efficiency ({sup 1}G{sub 4}) starts with a very low value (0.38%) for the synthesized nanocrystal (as grown) and strongly increases to 97% after thermal treatment at 550 °C for 6 h under argon flow. As a consequence of the thermal treatment at T=550 °C, the contributions of the (Nd×Tm) (Up{sub 1}) and (Nd×Yb×Tm) (Up{sub 2}) upconversion processes to the {sup 1}G{sub 4} luminescence are 33% (Up{sub 1}) and 67% for Up{sub 2}. Up{sub 2} process represented by Nd{sup 3+} ({sup 4}F{sub 3/2})→Yb{sup 3+} ({sup 2}F{sub 7/2}) followed by Yb{sup 3+} ({sup 2}F{sub 5/2})→Tm ({sup 3}H{sub 4})→Tm{sup 3+} ({sup 1}G{sub 4}) was previously reported as the main mechanism to produce the blue luminescence in Yb:Nd:Tm:YLiF{sub 4} and KY{sub 3}F{sub 10} bulk crystals. Results of X-ray diffraction analysis of nanopowder using the Rietveld method reveled that crystallite sizes remain unchanged (12–14 nm) after thermal treatments with T≤400 °C, while the

Modeling the influence of silver nanoparticles on the f–f luminescence of the EuEDTA complex in the polyvinylpirrolidone polymer

Energy Technology Data Exchange (ETDEWEB)

Couto dos Santos, M.A., E-mail: marcoscouto@ufs.br [Departamento de Física, Universidade Federal de Sergipe/CCET, São Cristóvão, SE 49100-000 (Brazil); Malta, O.L. [Departamento de Química Fundamental, Universidade Federalde Pernambuco/CCEN, Cidade Universitária, Recife, PE 50670-901 (Brazil); Reisfeld, R. [The Hebrew University of Jerusalem, Chemistry Institute, E. Safra Campus, 91904 Jerusalem (Israel)

2016-02-15

A theoretical analysis on experimental results previously obtained on the influence of silver nanoparticles in a polyvinylpirrolidone (PVP) polymer film containing a trivalent europium complex with EDTA ligand is made. Depending on the excitation source (at 393 nm with a xenon lamp or at 532 nm with a focused diode laser) the characteristic Eu{sup 3+} luminescence is observed to be enhanced by factors between 5 and 50. The theoretical analysis presumes a migration process of the EuEDTA complex units towards the silver nanoparticles, during the synthesis of the composite samples, and subsequently the treatment of the competition between local high field gradient effects and Eu{sup 3+} ion to the silver nanoparticles energy transfer successfully accounts for the observed luminescence enhancement factors. - Highlights: • Unusual luminescence enhancement of EuEDTA–silver nanoparticles–polyvinylpyrrolidone is treated theoretically. • A migration process of the EuEDTA complex units towards the silver nanoparticles is assumed. • The local high field gradient effects successfully accounts for the observed unusual luminescence enhancement factor of 50.

A highly accurate method for determination of dissolved oxygen: Gravimetric Winkler method

International Nuclear Information System (INIS)

Helm, Irja; Jalukse, Lauri; Leito, Ivo

2012-01-01

Highlights: ► Probably the most accurate method available for dissolved oxygen concentration measurement was developed. ► Careful analysis of uncertainty sources was carried out and the method was optimized for minimizing all uncertainty sources as far as practical. ► This development enables more accurate calibration of dissolved oxygen sensors for routine analysis than has been possible before. - Abstract: A high-accuracy Winkler titration method has been developed for determination of dissolved oxygen concentration. Careful analysis of uncertainty sources relevant to the Winkler method was carried out and the method was optimized for minimizing all uncertainty sources as far as practical. The most important improvements were: gravimetric measurement of all solutions, pre-titration to minimize the effect of iodine volatilization, accurate amperometric end point detection and careful accounting for dissolved oxygen in the reagents. As a result, the developed method is possibly the most accurate method of determination of dissolved oxygen available. Depending on measurement conditions and on the dissolved oxygen concentration the combined standard uncertainties of the method are in the range of 0.012–0.018 mg dm −3 corresponding to the k = 2 expanded uncertainty in the range of 0.023–0.035 mg dm −3 (0.27–0.38%, relative). This development enables more accurate calibration of electrochemical and optical dissolved oxygen sensors for routine analysis than has been possible before.

Thermal dependence of luminescence lifetimes and radioluminescence in quartz

Energy Technology Data Exchange (ETDEWEB)

Pagonis, V., E-mail: vpagonis@mcdaniel.edu [McDaniel College, Physics Department, Westminster, MD 21157 (United States); Chithambo, M.L. [Department of Physics and Electronics, Rhodes University, PO BOX 94, Grahamstown 6140 (South Africa); Chen, R. [Raymond and Beverly Sackler School of Physics and Astronomy, Tel-Aviv University, Tel-Aviv 69978 (Israel); Chruścińska, A. [Institute of Physics, Nicholas Copernicus University, 87-100 Toruń (Poland); Fasoli, M. [Department of Materials Science, University of Milano-Bicocca, Via Cozzi 53, 20125 Milano (Italy); Li, S.H. [Department of Earth Sciences, The University of Hong Kong (Hong Kong); Martini, M. [Department of Materials Science, University of Milano-Bicocca, Via Cozzi 53, 20125 Milano (Italy); Ramseyer, K. [Institut für Geologie, Baltzerstrasse 1-3, 3012 Bern (Switzerland)

2014-01-15

During time-resolved optical stimulation experiments (TR-OSL), one uses short light pulses to separate the stimulation and emission of luminescence in time. Experimental TR-OSL results show that the luminescence lifetime in quartz of sedimentary origin is independent of annealing temperature below 500 °C, but decreases monotonically thereafter. These results have been interpreted previously empirically on the basis of the existence of two separate luminescence centers L{sub H} and L{sub L} in quartz, each with its own distinct luminescence lifetime. Additional experimental evidence also supports the presence of a non-luminescent hole reservoir R, which plays a critical role in the predose effect in this material. This paper extends a recently published analytical model for thermal quenching in quartz, to include the two luminescence centers L{sub H} and L{sub L}, as well as the hole reservoir R. The new extended model involves localized electronic transitions between energy states within the two luminescence centers, and is described by a system of differential equations based on the Mott–Seitz mechanism of thermal quenching. It is shown that by using simplifying physical assumptions, one can obtain analytical solutions for the intensity of the light during a TR-OSL experiment carried out with previously annealed samples. These analytical expressions are found to be in good agreement with the numerical solutions of the equations. The results from the model are shown to be in quantitative agreement with published experimental data for commercially available quartz samples. Specifically the model describes the variation of the luminescence lifetimes with (a) annealing temperatures between room temperature and 900 °C, and (b) with stimulation temperatures between 20 and 200 °C. This paper also reports new radioluminescence (RL) measurements carried out using the same commercially available quartz samples. Gaussian deconvolution of the RL emission spectra was

Phosphorescence quantum yield determination with time-gated fluorimeter and Tb(III)-acetylacetonate as luminescence reference

Energy Technology Data Exchange (ETDEWEB)

Penzkofer, A., E-mail: alfons.penzkofer@physik.uni-regensburg.de [Fakultät für Physik, Universität Regensburg, Universitätsstrasse 31, D-93053 Regensburg (Germany)

2013-03-29

Highlights: ► Procedure for absolute phosphorescence quantum yield measurement is described. ► Experimental setup for absolute luminescence quantum yield standard calibration. ► Tb(acac){sub 3} proposed as phosphorescence quantum yield reference standard. ► Luminescence quantum yield of Tb(acac){sub 3} in cyclohexane measured. ► Luminescence lifetime of Tb(acac){sub 3} in cyclohexane measured. - Abstract: Phosphorescence quantum yield measurements of fluorescent and phosphorescent samples require the use of time-gated fluorimeters in order to discriminate against the fluorescence contribution. As reference standard a non-fluorescent luminescent compound is needed for absolute phosphorescence quantum yield determination. For this purpose the luminescence behavior of the rare earth chelate terbium(III)-acetylacetonate (Tb(acac){sub 3}) was studied (determination of luminescence quantum yield and luminescence lifetime). The luminescence quantum yield of Tb(acac){sub 3} was determined by using an external light source and operating the fluorimeter in chemo/bioluminescence mode with a fluorescent dye (rhodamine 6G in methanol) as reference standard. A procedure is developed for absolute luminescence (phosphorescence) quantum yield determination of samples under investigation with a time-gated fluorimeter using a non-fluorescent luminescent compound of known luminescence quantum yield and luminescence lifetime.

Luminescence of Y2O2S-Eu3+ and Ln2O2S-Tb3+ films grown by the method of photostimulated epitaxy

International Nuclear Information System (INIS)

Maksimovskij, S.N.; Sidorov, P.P.; Sluch, M.I.

1990-01-01

Study of luminescence of Y 2 O 2 S-Eu 3+ (1) and La 2 O 2 S-Tb 3+ (2) films, grown from vapor phase by photostimulated epitaxy method is carried out. Spectroscopic analysis data showed that films(1) spectra contain narrow lines, relating to C 3V symmetry centre, and wider lines, relating to C S symmetry centre. Films(2) possess intensive luminescence in green spectral region, but luminescence lines are wider due to higher number of defects. As to production of film luminescent screens the method is shown to be promising

A problem in gravimetric method for the determination of rare earth elements as oxide after the fluoride separation

International Nuclear Information System (INIS)

Takada, Kunio

1979-01-01

For the gravimetric determination of lanthanum, it was precipitated as fluoride and converted to oxide by igniting (ca. 930 0 C) in a town gas flame. However, the oxidation of lanthanum fluoride by ignition was incomplete, the major part of the precipitate being converted to oxyfluoride (LaOF) and a mixture of oxide and oxyfluoride resulted. Therefore, analytical results were generally (5 -- 7)% higher than theoretically expected. The lanthanum fluoride became converted into the oxide by repeating ignition (ca. 1070 0 C) three times, each for (30 -- 40)min. However, the weight was lower than that of the corresponding sesquioxide, La 2 O 3 . Except for ytterbium and lutetium, gravimetric results as oxides for the other rare earth elements (Y, Pr, Nd, Sm, Eu and Gd) were higher than theoretical values. Therefore, the precipitation of the rare earth elements as fluoride and the subsequent determination as oxide by ignition of the fluoride could not be recommended as the gravimetric method for the rare earths. In order to obtain accurate results for major to minor amounts of the rare earth elements, an EDTA titration at pH 6 should be used after the dissolution of fluoride in acid, if the fluoride precipitation separation is involved. (author)

The use of cerium(IV) phosphate for the gravimetric determination and separation of cerium

International Nuclear Information System (INIS)

Masin, V.; Dolezal, J.

1978-01-01

A method for the gravimetric determination of cerium as Ce 3 (PO 4 ) 4 is described. Cerium can be separated from many metals in this form, as well as from permanganate and dichromate; the cerium separated can then be titrated with iron(II) solution. The method was verified for the determination of cerium in a rare earth concentrate. (Auth.)

Design and realization of the high-precision weighing systems as the gravimetric references in PTB's national water flow standard

International Nuclear Information System (INIS)

Engel, Rainer; Beyer, Karlheinz; Baade, Hans-Joachim

2012-01-01

PTB's ‘Hydrodynamic Test Field’, which represents a high-accuracy water flow calibration facility, serves as the national primary standard for liquid flow measurands. As the core reference device of this flow facility, a gravimetric standard has been incorporated, which comprises three special-design weighing systems: 300 kg, 3 tons and 30 tons. These gravimetric references were realized as a combination of a strain-gauge-based and an electromagnetic-force-compensation load-cell-based balance, each. Special emphasis had to be placed upon the dynamics design of the whole weighing system, due to the high measurement resolution and the dynamic behavior of the weighing systems, which are dynamically affected by mechanical vibrations caused by environmental impacts, flow machinery operation, flow noise in the pipework and induced wave motions in the weigh tanks. Taking into account all the above boundary conditions, the design work for the gravimetric reference resulted in a concrete foundation ‘rock’ of some 300 tons that rests on a number of vibration isolators. In addition to these passively operating vibration isolators, the vibration damping effect is enhanced by applying an electronic level regulation device. (paper)

Resonant gravimetric immunosensing based on capacitive micromachined ultrasound transducers

KAUST Repository

Viržonis, Darius

2014-04-08

High-frequency (40 MHz) and low-frequency (7 MHz) capacitive micromachined ultrasound transducers (CMUT) were fabricated and tested for use in gravimetric detection of biomolecules. The low-frequency CMUT sensors have a gold-coated surface, while the high-frequency sensors have a silicon nitride surface. Both surfaces were functionalized with bovine leukemia virus antigen gp51 acting as the antigen. On addition of an a specific antibody labeled with horseradish peroxidase (HRP), the antigen/antibody complex is formed on the surface and quantified by HRP-catalyzed oxidation of tetramethylbenzidine. It has been found that a considerably smaller quantity of immuno complex is formed on the high frequency sensor surface. In parallel, the loading of the surface of the CMUT was determined via resonance frequency and electromechanical resistance readings. Following the formation of the immuno complexes, the resonance frequencies of the low-frequency and high-frequency sensors decrease by up to 420 and 440 kHz, respectively. Finite element analysis reveals that the loading of the (gold-coated) low frequency sensors is several times larger than that on high frequency sensors. The formation of the protein film with pronounced elasticity and stress on the gold surface case is discussed. We also discuss the adoption of this method for the detection of DNA using a hybridization assay following polymerase chain reaction.

Thermally stimulated luminescence in ZnMoO{sub 4} crystals

Energy Technology Data Exchange (ETDEWEB)

Degoda, V.Ya.; Kogut, Ya.P.; Moroz, I.M. [Kyiv National Taras Shevchenko University, MSP 03680 Kyiv (Ukraine); Danevich, F.A. [Institute for Nuclear Research, MSP 03680 Kyiv (Ukraine)

2017-03-15

Thermally stimulated luminescence in ZnMoO{sub 4} crystals after X-ray irradiation at temperatures 8 K, 85 K and 295 K was studied. A theoretical model of crystal phosphor with three types of traps (shallow, phosphorescent and deep) is proposed. Simple analytic solutions of the kinetic equations system describing localized electrons on the traps and holes on recombination centres were obtained by using approximations accepted in the classic theories of crystal phosphors. Analytical curves describing thermally stimulated luminescence were obtained. A substantial effect of the different traps concentrations ratios on the thermally stimulated luminescence and conductivity peaks shapes is shown. A good agreement of the theoretical curves with the experimental data for the thermally stimulated luminescence peak at 114 K is obtained.

Influence of Nano sized Silicon Oxide on the Luminescent Properties of Zn O Nanoparticles

International Nuclear Information System (INIS)

Shvalagin, V.; Grodziuk, G.; Kurmach, M.; Granchak, V.; Sarapulova, O.; Sherstiuk, V.

2016-01-01

For practical use of nano sized zinc oxide as the phosphor its luminescence quantum yields should be maximized. The aim of this work was to enhance luminescent properties of Zn O nanoparticles and obtain high-luminescent Zn O/SiO 2 composites using simpler approaches to colloidal synthesis. The luminescence intensity of zinc oxide nanoparticles was increased about 3 times by addition of silica nano crystals to the source solutions during the synthesis of Zn O nanoparticles. Then the quantum yield of luminescence of the obtained Zn O/SiO 2 composites is more than 30%. Such an impact of silica is suggested to be caused by the distribution of Zn O nano crystals on the surface of silica, which reduces the probability of separation of photo generated charges between the zinc oxide nanoparticles of different sizes, and as a consequence, there is a significant increase of the luminescence intensity of Zn O nanoparticles. This way of increasing nano-Zn O luminescence intensity facilitates its use in a variety of devices, including optical ultraviolet and visible screens, luminescent markers, antibacterial coatings, luminescent solar concentrators, luminescent inks for security printing, and food packaging with abilities of informing consumers about the quality and safety of the packaged product.

Luminescence and luminescence quenching of Eu{sub 2}Mo{sub 4}O{sub 15}

Energy Technology Data Exchange (ETDEWEB)

Janulevicius, Matas; Grigorjevaite, Julija; Merkininkaite, Greta [Department of Analytical and Environmental Chemistry, Vilnius University, Naugarduko 24, LT-03225 Vilnius (Lithuania); Sakirzanovas, Simas [Department of Applied Chemistry, Vilnius University, Naugarduko 24, LT-03225 Vilnius (Lithuania); Katelnikovas, Arturas, E-mail: arturas.katelnikovas@chf.vu.lt [Department of Analytical and Environmental Chemistry, Vilnius University, Naugarduko 24, LT-03225 Vilnius (Lithuania)

2016-11-15

A polycrystalline Eu{sub 2}Mo{sub 4}O{sub 15} phosphor sample was prepared by high temperature solid state reaction. Phase purity and morphological features of the phosphor were investigated by X-ray diffraction and scanning electron microscopy, respectively. Reflectance spectra showed that the optical band gap of Eu{sub 2}Mo{sub 4}O{sub 15} is 2.95 eV. Phosphor emits intensive red light when excited with 394 and 465 nm radiation. Temperature dependent emission and luminescence lifetime measurements revealed that external and internal quantum yields decrease at the same rate and that luminescence quenches due to photoionization. The calculated external quantum yields for 394 and 465 nm excitation were 7.8% and 53.5%, respectively.

Time-Resolved Gravimetric Method To Assess Degassing of Roasted Coffee.

Science.gov (United States)

Smrke, Samo; Wellinger, Marco; Suzuki, Tomonori; Balsiger, Franz; Opitz, Sebastian E W; Yeretzian, Chahan

2018-05-30

During the roasting of coffee, thermally driven chemical reactions lead to the formation of gases, of which a large fraction is carbon dioxide (CO 2 ). Part of these gases is released during roasting while part is retained inside the porous structure of the roasted beans and is steadily released during storage or more abruptly during grinding and extraction. The release of CO 2 during the various phases from roasting to consumption is linked to many important properties and characteristics of coffee. It is an indicator for freshness, plays an important role in shelf life and in packaging, impacts the extraction process, is involved in crema formation, and may affect the sensory profile in the cup. Indeed, and in view of the multiple roles it plays, CO 2 is a much underappreciated and little examined molecule in coffee. Here, we introduce an accurate, quantitative, and time-resolved method to measure the release kinetics of gases from whole beans and ground coffee using a gravimetric approach. Samples were placed in a container with a fitted capillary to allow gases to escape. The time-resolved release of gases was measured via the weight loss of the container filled with coffee. Long-term stability was achieved using a customized design of a semimicro balance, including periodic and automatic zero value measurements and calibration procedures. The novel gravimetric methodology was applied to a range of coffee samples: (i) whole Arabica beans and (ii) ground Arabica and Robusta, roasted to different roast degrees and at different speeds (roast air temperatures). Modeling the degassing rates allowed structural and mechanistic interpretation of the degassing process.

Characterization and luminescent properties of Eu3+ doped Gd2Zr2O7 nanopowders

International Nuclear Information System (INIS)

Rabasovic, M.S.; Sevic, D.; Krizan, J.; Terzic, M.; Mozina, J.; Marinkovic, B.P.; Savic-Sevic, S.; Mitric, M.; Rabasovic, M.D.; Romcevic, N.

2015-01-01

Highlights: • Nanopowders Gd 2 Zr 2 O 7 doped by europium ions (Eu 3+ ) have been synthesized. • Their luminescence properties have been measured at room temperature. • The temporal evolution of laser induced phenomena are presented using time-resolved technique. • Lifetime analysis for luminescence bands in emission spectra has been done. - Abstract: Nanopowders based on gadolinium zirconium oxide (Gd 2 Zr 2 O 7 ) doped by europium ions (Eu 3+ ) were successfully prepared using a flame combustion method. This material is suitable for various optical devices. The structure of prepared materials has been confirmed and characterized using X-ray powder diffraction (XRD), scanning electron microscope (SEM) and photoluminescence (PL) techniques. The luminescence properties of synthesized nanopowders were characterized by emission spectra and luminescence lifetimes by using the streak camera system. PL spectra were obtained at three different excitation wavelengths (Optical Parametric Oscilator (OPO) at 360 nm, laser diode at 365 nm and Ar laser line at 514.5 nm). The strong emission lines at 611 nm and 630 nm corresponding to the 5 D 0 → 7 F 2 long lived transition could be used as a new red light source in optical devices

Piezoelectrically-induced stress-luminescence phenomenon in CaAl2O4:Eu2+

International Nuclear Information System (INIS)

Wei, Yongbin; Wu, Zheng; Jia, Yanmin; Liu, Yongsheng

2015-01-01

Piezoelectrically-induced stress-luminescence in the CaAl 2 O 4 :Eu 2+ was investigated. Blue light that was visible to the naked eye could be observed in the dark when a pulse force of ∼7.7 kN was applied to the sample. The intensity of the stress-luminescence strongly depended on the magnitude of the applied force during a pulse cycle. The intensity decreased with repetitive application of pulse stress and was completely recovered after irradiation with ultraviolet light. It is suggested that the stress-luminescence effect in CaAl 2 O 4 :Eu 2+ arises from the piezoelectrically-induced de-trapping of the charge carriers. A CaAl 2 O 4 :Eu 2+ ceramic that exhibits a stress-luminescence effect has potential applications in smart stress optically-sensing devices. - Highlights: • The strong induced stress-luminescence in CaAl 2 O 4 :Eu 2+ was observed. • The stress-luminescent intensity strongly depends on the magnitude of force. • The stress-luminescence could be completely recovered after the UV irradiation. • The strong stress-luminescent effect is potential in stress-light sensors

Density Imaging of Puy de Dôme Volcano by Joint Inversion of Muographic and Gravimetric Data

Science.gov (United States)

Barnoud, A.; Niess, V.; Le Ménédeu, E.; Cayol, V.; Carloganu, C.

2016-12-01

We aim at jointly inverting high density muographic and gravimetric data to robustly infer the density structure of volcanoes. We use the puy de Dôme volcano in France as a proof of principle since high quality data sets are available for both muography and gravimetry. Gravimetric inversion and muography are independent methods that provide an estimation of density distributions. On the one hand, gravimetry allows to reconstruct 3D density variations by inversion. This process is well known to be ill-posed and intrinsically non unique, thus it requires additional constraints (eg. a priori density model). On the other hand, muography provides a direct measurement of 2D mean densities (radiographic images) from the detection of high energy atmospheric muons crossing the volcanic edifice. 3D density distributions can be computed from several radiographic images, but the number of images is generally limited by field constraints and by the limited number of available telescopes. Thus, muon tomography is also ill-posed in practice.In the case of the puy de Dôme volcano, the density structures inferred from gravimetric data (Portal et al. 2016) and from muographic data (Le Ménédeu et al. 2016) show a qualitative agreement but cannot be compared quantitatively. Because each method has different intrinsic resolutions due to the physics (Jourde et al., 2015), the joint inversion is expected to improve the robustness of the inversion. Such joint inversion has already been applied in a volcanic context (Nishiyama et al., 2013).Volcano muography requires state-of-art, high-resolution and large-scale muon detectors (Ambrosino et al., 2015). Instrumental uncertainties and systematic errors may constitute an important limitation for muography and should not be overlooked. For instance, low-energy muons are detected together with ballistic high-energy muons, decreasing the measured value of the mean density closed to the topography.Here, we jointly invert the gravimetric and

Determination of uranium by a gravimetric-volumetric titration method

International Nuclear Information System (INIS)

Krtil, J.

1998-01-01

A volumetric-gravimetric modification of a method for the determination of uranium based on the reduction of uranium to U (IV) in a phosphoric acid medium and titration with a standard potassium dichromate solution is described. More than 99% of the stoichiometric amount of the titrating solution is weighed and the remainder is added volumetrically by using the Mettler DL 40 RC Memotitrator. Computer interconnected with analytical balances collects continually the data on the analyzed samples and evaluates the results of determination. The method allows to determine uranium in samples of uranium metal, alloys, oxides, and ammonium diuranate by using aliquot portions containing 30 - 100 mg of uranium with the error of determination, expressed as the relative standard deviation, of 0.02 - 0.05%. (author)

Nuclear fuel technology - Determination of uranium in uranyl nitrate solutions of nuclear grade quality - Gravimetric method

International Nuclear Information System (INIS)

2003-01-01

This International Standard specifies a precise and accurate gravimetric method for determining the mass fraction of uranium in uranyl nitrate solutions of nuclear grade quality containing more than 100 g/kg of uranium. Non-volatile impurities influence the accuracy of the method

Metal-enhanced luminescence: Current trend and future perspectives- A review

International Nuclear Information System (INIS)

Ranjan, Rajeev; Esimbekova, Elena N.; Kirillova, Maria A.; Kratasyuk, Valentina A.

2017-01-01

Optically enhanced biosensing strategies are prerequisites for developing miniature and highly sensitive multiplexed analytical platforms. Such smart biosensing systems are highly promising for use in the fields of biomedicine and environmental monitoring. Optical signal enhancement during bioassays is attributed to the complex opto-electronic interactions of incoming photonic signals at the nanomaterial interface. Research on the use of metals other than gold and silver for such purposes tends to extend the spectral window to observe luminescence enhancement effects. Such manifold increase in luminescence may be explained by the principles of plasmon coupling, directional emission led high collection efficiency, Rayleigh scattering and related opto-electronic events. The present review begins with a mechanistic description of important phenomena associated with metal-induced luminescence enhancement, particularly focusing on the origin of metal-enhanced luminescence. This review further analyses the hybrid nanostructure capabilities responsible for maintaining unique opto-electronic properties during bio-functionalisation. Current research trends in this area, future scope of this field for designing useful bioassays and concluding remarks are then discussed. - Highlights: • Nanomaterials significantly differ from their bulk counterparts. • Strong and pronounced photophysical effects at the metal surface provide opportunities for designing novel biosensors. • Metal-enhanced luminescence increases the quantum yield of luminescent reactions. • Under optimal conditions, plasmon coupling enhances the optical effects at the nanometal surface.

Metal-enhanced luminescence: Current trend and future perspectives- A review

Energy Technology Data Exchange (ETDEWEB)

Ranjan, Rajeev [Laboratory of Bioluminescent Biotechnologies, Department of Biophysics, Institute of Fundamental Biology and Biotechnology, Siberian Federal University, 79 Svobodny Prospect, Krasnoyarsk 660041 (Russian Federation); Esimbekova, Elena N., E-mail: esimbekova@yandex.ru [Laboratory of Bioluminescent Biotechnologies, Department of Biophysics, Institute of Fundamental Biology and Biotechnology, Siberian Federal University, 79 Svobodny Prospect, Krasnoyarsk 660041 (Russian Federation); Institute of Biophysics SB RAS, Federal Research Center “Krasnoyarsk Science Center SB RAS”, Akademgorodok 50/50, Krasnoyarsk 660036 (Russian Federation); Kirillova, Maria A. [Laboratory of Bioluminescent Biotechnologies, Department of Biophysics, Institute of Fundamental Biology and Biotechnology, Siberian Federal University, 79 Svobodny Prospect, Krasnoyarsk 660041 (Russian Federation); Kratasyuk, Valentina A. [Laboratory of Bioluminescent Biotechnologies, Department of Biophysics, Institute of Fundamental Biology and Biotechnology, Siberian Federal University, 79 Svobodny Prospect, Krasnoyarsk 660041 (Russian Federation); Institute of Biophysics SB RAS, Federal Research Center “Krasnoyarsk Science Center SB RAS”, Akademgorodok 50/50, Krasnoyarsk 660036 (Russian Federation)

2017-06-08

Optically enhanced biosensing strategies are prerequisites for developing miniature and highly sensitive multiplexed analytical platforms. Such smart biosensing systems are highly promising for use in the fields of biomedicine and environmental monitoring. Optical signal enhancement during bioassays is attributed to the complex opto-electronic interactions of incoming photonic signals at the nanomaterial interface. Research on the use of metals other than gold and silver for such purposes tends to extend the spectral window to observe luminescence enhancement effects. Such manifold increase in luminescence may be explained by the principles of plasmon coupling, directional emission led high collection efficiency, Rayleigh scattering and related opto-electronic events. The present review begins with a mechanistic description of important phenomena associated with metal-induced luminescence enhancement, particularly focusing on the origin of metal-enhanced luminescence. This review further analyses the hybrid nanostructure capabilities responsible for maintaining unique opto-electronic properties during bio-functionalisation. Current research trends in this area, future scope of this field for designing useful bioassays and concluding remarks are then discussed. - Highlights: • Nanomaterials significantly differ from their bulk counterparts. • Strong and pronounced photophysical effects at the metal surface provide opportunities for designing novel biosensors. • Metal-enhanced luminescence increases the quantum yield of luminescent reactions. • Under optimal conditions, plasmon coupling enhances the optical effects at the nanometal surface.

Luminescence imaging of water during proton-beam irradiation for range estimation

Energy Technology Data Exchange (ETDEWEB)

Yamamoto, Seiichi, E-mail: s-yama@met.nagoya-u.ac.jp; Okumura, Satoshi; Komori, Masataka [Radiological and Medical Laboratory Sciences, Nagoya University Graduate School of Medicine, Nagoya 461-8673 (Japan); Toshito, Toshiyuki [Department of Proton Therapy Physics, Nagoya Proton Therapy Center, Nagoya City West Medical Center, Nagoya 462-8508 (Japan)

2015-11-15

Purpose: Proton therapy has the ability to selectively deliver a dose to the target tumor, so the dose distribution should be accurately measured by a precise and efficient method. The authors found that luminescence was emitted from water during proton irradiation and conjectured that this phenomenon could be used for estimating the dose distribution. Methods: To achieve more accurate dose distribution, the authors set water phantoms on a table with a spot scanning proton therapy system and measured the luminescence images of these phantoms with a high-sensitivity, cooled charge coupled device camera during proton-beam irradiation. The authors imaged the phantoms of pure water, fluorescein solution, and an acrylic block. Results: The luminescence images of water phantoms taken during proton-beam irradiation showed clear Bragg peaks, and the measured proton ranges from the images were almost the same as those obtained with an ionization chamber. Furthermore, the image of the pure-water phantom showed almost the same distribution as the tap-water phantom, indicating that the luminescence image was not related to impurities in the water. The luminescence image of the fluorescein solution had ∼3 times higher intensity than water, with the same proton range as that of water. The luminescence image of the acrylic phantom had a 14.5% shorter proton range than that of water; the proton range in the acrylic phantom generally matched the calculated value. The luminescence images of the tap-water phantom during proton irradiation could be obtained in less than 2 s. Conclusions: Luminescence imaging during proton-beam irradiation is promising as an effective method for range estimation in proton therapy.

Luminescence imaging of water during proton-beam irradiation for range estimation

International Nuclear Information System (INIS)

Yamamoto, Seiichi; Okumura, Satoshi; Komori, Masataka; Toshito, Toshiyuki

2015-01-01

Purpose: Proton therapy has the ability to selectively deliver a dose to the target tumor, so the dose distribution should be accurately measured by a precise and efficient method. The authors found that luminescence was emitted from water during proton irradiation and conjectured that this phenomenon could be used for estimating the dose distribution. Methods: To achieve more accurate dose distribution, the authors set water phantoms on a table with a spot scanning proton therapy system and measured the luminescence images of these phantoms with a high-sensitivity, cooled charge coupled device camera during proton-beam irradiation. The authors imaged the phantoms of pure water, fluorescein solution, and an acrylic block. Results: The luminescence images of water phantoms taken during proton-beam irradiation showed clear Bragg peaks, and the measured proton ranges from the images were almost the same as those obtained with an ionization chamber. Furthermore, the image of the pure-water phantom showed almost the same distribution as the tap-water phantom, indicating that the luminescence image was not related to impurities in the water. The luminescence image of the fluorescein solution had ∼3 times higher intensity than water, with the same proton range as that of water. The luminescence image of the acrylic phantom had a 14.5% shorter proton range than that of water; the proton range in the acrylic phantom generally matched the calculated value. The luminescence images of the tap-water phantom during proton irradiation could be obtained in less than 2 s. Conclusions: Luminescence imaging during proton-beam irradiation is promising as an effective method for range estimation in proton therapy

Stimulation of Cysteine-Coated CdSe/ZnS Quantum Dot Luminescence by meso-Tetrakis (p-sulfonato-phenyl) Porphyrin

Science.gov (United States)

Parra, Gustavo G.; Ferreira, Lucimara P.; Gonçalves, Pablo J.; Sizova, Svetlana V.; Oleinikov, Vladimir A.; Morozov, Vladimir N.; Kuzmin, Vladimir A.; Borissevitch, Iouri E.

2018-02-01

Interaction between porphyrins and quantum dots (QD) via energy and/or charge transfer is usually accompanied by reduction of the QD luminescence intensity and lifetime. However, for CdSe/ZnS-Cys QD water solutions, kept at 276 K during 3 months (aged QD), the significant increase in the luminescence intensity at the addition of meso-tetrakis (p-sulfonato-phenyl) porphyrin (TPPS4) has been observed in this study. Aggregation of QD during the storage provokes reduction in the quantum yield and lifetime of their luminescence. Using steady-state and time-resolved fluorescence techniques, we demonstrated that TPPS4 stimulated disaggregation of aged CdSe/ZnS-Cys QD in aqueous solutions, increasing the quantum yield of their luminescence, which finally reached that of the fresh-prepared QD. Disaggregation takes place due to increase in electrostatic repulsion between QD at their binding with negatively charged porphyrin molecules. Binding of just four porphyrin molecules per single QD was sufficient for total QD disaggregation. The analysis of QD luminescence decay curves demonstrated that disaggregation stronger affected the luminescence related with the electron-hole annihilation in the QD shell. The obtained results demonstrate the way to repair aged QD by adding of some molecules or ions to the solutions, stimulating QD disaggregation and restoring their luminescence characteristics, which could be important for QD biomedical applications, such as bioimaging and fluorescence diagnostics. On the other hand, the disaggregation is important for QD applications in biology and medicine since it reduces the size of the particles facilitating their internalization into living cells across the cell membrane.

Influence of sample oxidation on the nature of optical luminescence from porous silicon

International Nuclear Information System (INIS)

Coulthard, I.; Antel, W. J. Jr.; Freeland, J. W.; Sham, T. K.; Naftel, S. J.; Zhang, P.

2000-01-01

Site-selective luminescence experiments were performed upon porous-silicon samples exposed to varying degrees of oxidation. The source of different luminescence bands was determined to be due to either quantum confinement in nanocrystalline silicon or defective silicon oxide. Of particular interest is the defective silicon-oxide luminescence band found at 2.1 eV, which was found to frequently overlap with a luminescence band from nanocrystalline silicon. Some of the historical confusion and debate with regards to the source of luminescence from porous silicon can be attributed to this overlap. (c) 2000 American Institute of Physics

Hormesis response of marine and freshwater luminescent bacteria to metal exposure

Directory of Open Access Journals (Sweden)

KAILI SHEN

2009-01-01

Full Text Available The stimulatory effect of low concentrations of toxic chemicals on organismal metabolism, referred to as hormesis, has been found to be common in the widely used luminescence bioassay. This paper aims to study the hormesis phenomenon in both marine and freshwater luminescent bacteria, named Photobacterium phosphorem and Vibrio qinghaiensis. The effects of Cu (II, Zn (II, Cd (II and Cr (VI on luminescence of these two bacteria were studied for 0 to 75 minutes exposure by establishing dose- and time-response curves. A clear hormesis phenomenon was observed in all four testing metals at low concentrations under the condition of luminescence assays.

Charged defects during alpha-irradiation of actinide oxides as revealed by Raman and luminescence spectroscopy

International Nuclear Information System (INIS)

Mohun, R.; Desgranges, L.; Léchelle, J.; Simon, P.; Guimbretière, G.; Canizarès, A.; Duval, F.; Jegou, C.; Magnin, M.; Clavier, N.; Dacheux, N.; Valot, C.; Vauchy, R.

2016-01-01

We have recently evidenced an original Raman signature of alpha irradiation-induced defects in UO 2 . In this study, we aim to determine whether the same signature also exists in different actinide oxides, namely ThO 2 and PuO 2 . Sintered UO 2 and ThO 2 were initially irradiated with 21 MeV He 2+ ions using a cyclotron device and were subjected to an in situ luminescence experiment followed by Raman analysis. In addition, a PuO 2 sample which had accumulated self-irradiation damage due to alpha particles was investigated only by Raman measurement. Results obtained for the initially white ThO 2 showed that a blue color appeared in the irradiated areas as well as luminescence signals during irradiation. However, Raman spectroscopic analysis showed the absence of Raman signature in ThO 2 . In contrast, the irradiated UO 2 and PuO 2 confirmed the presence of the Raman signature but no luminescence peaks were observed. The proposed mechanism involves electronic defects in ThO 2 , while a coupling between electronic defects and phonons is required to explain the Raman spectra for UO 2 and PuO 2 .

Amino-Functionalized Luminescent Metal-Organic Framework Test Paper for Rapid and Selective Sensing of SO2 Gas and Its Derivatives by Luminescence Turn-On Effect.

Science.gov (United States)

Wang, Meng; Guo, Lin; Cao, Dapeng

2018-03-06

Rapid and selective sensing of sulfur dioxide (SO 2 ) gas has attracted more and more attention because SO 2 not only causes environmental pollution but also severely affects the health of human beings. Here we report an amino-functionalized luminescent metal-organic framework (MOF) material (i.e., MOF-5-NH 2 ) and further investigate its sensing property for SO 2 gas and its derivatives as a luminescent probe. The results indicate that the MOF-5-NH 2 probe can selectively and sensitively sense SO 2 derivatives (i.e., SO 3 2- ) in real time by a luminescence turn-on effect with a lower detection limit of 0.168 ppm and a response time of less than 15 s. Importantly, the luminescence turn-on phenomenon can be observed by the naked eye. We also assembled MOF-5-NH 2 into a test paper to achieve the aim of portable detection, and the lower-limit concentration of the test paper for sensing SO 2 in real time was found to be about 0.05 ppm. Moreover, MOF-5-NH 2 also shows good anti-interference ability, strong luminescence stability, and reusability, which means that this material is an excellent sensing candidate. The amino functionalization may also provide a modification strategy to design luminescent sensors for other atmospheric pollutants.

Luminescence imaging of water during carbon-ion irradiation for range estimation

Energy Technology Data Exchange (ETDEWEB)

Yamamoto, Seiichi, E-mail: s-yama@met.nagoya-u.ac.jp; Komori, Masataka; Koyama, Shuji; Morishita, Yuki; Sekihara, Eri [Radiological and Medical Laboratory Sciences, Nagoya University Graduate School of Medicine, Higashi-ku, Nagoya, Aichi 461-8673 (Japan); Akagi, Takashi; Yamashita, Tomohiro [Hygo Ion Beam Medical Center, Hyogo 679-5165 (Japan); Toshito, Toshiyuki [Department of Proton Therapy Physics, Nagoya Proton Therapy Center, Nagoya City West Medical Center, Aichi 462-8508 (Japan)

2016-05-15

Purpose: The authors previously reported successful luminescence imaging of water during proton irradiation and its application to range estimation. However, since the feasibility of this approach for carbon-ion irradiation remained unclear, the authors conducted luminescence imaging during carbon-ion irradiation and estimated the ranges. Methods: The authors placed a pure-water phantom on the patient couch of a carbon-ion therapy system and measured the luminescence images with a high-sensitivity, cooled charge-coupled device camera during carbon-ion irradiation. The authors also carried out imaging of three types of phantoms (tap-water, an acrylic block, and a plastic scintillator) and compared their intensities and distributions with those of a phantom containing pure-water. Results: The luminescence images of pure-water phantoms during carbon-ion irradiation showed clear Bragg peaks, and the measured carbon-ion ranges from the images were almost the same as those obtained by simulation. The image of the tap-water phantom showed almost the same distribution as that of the pure-water phantom. The acrylic block phantom’s luminescence image produced seven times higher luminescence and had a 13% shorter range than that of the water phantoms; the range with the acrylic phantom generally matched the calculated value. The plastic scintillator showed ∼15 000 times higher light than that of water. Conclusions: Luminescence imaging during carbon-ion irradiation of water is not only possible but also a promising method for range estimation in carbon-ion therapy.

Luminescence imaging of water during carbon-ion irradiation for range estimation

International Nuclear Information System (INIS)

Yamamoto, Seiichi; Komori, Masataka; Koyama, Shuji; Morishita, Yuki; Sekihara, Eri; Akagi, Takashi; Yamashita, Tomohiro; Toshito, Toshiyuki

2016-01-01

Purpose: The authors previously reported successful luminescence imaging of water during proton irradiation and its application to range estimation. However, since the feasibility of this approach for carbon-ion irradiation remained unclear, the authors conducted luminescence imaging during carbon-ion irradiation and estimated the ranges. Methods: The authors placed a pure-water phantom on the patient couch of a carbon-ion therapy system and measured the luminescence images with a high-sensitivity, cooled charge-coupled device camera during carbon-ion irradiation. The authors also carried out imaging of three types of phantoms (tap-water, an acrylic block, and a plastic scintillator) and compared their intensities and distributions with those of a phantom containing pure-water. Results: The luminescence images of pure-water phantoms during carbon-ion irradiation showed clear Bragg peaks, and the measured carbon-ion ranges from the images were almost the same as those obtained by simulation. The image of the tap-water phantom showed almost the same distribution as that of the pure-water phantom. The acrylic block phantom’s luminescence image produced seven times higher luminescence and had a 13% shorter range than that of the water phantoms; the range with the acrylic phantom generally matched the calculated value. The plastic scintillator showed ∼15 000 times higher light than that of water. Conclusions: Luminescence imaging during carbon-ion irradiation of water is not only possible but also a promising method for range estimation in carbon-ion therapy.

Luminescence study of spodumene

International Nuclear Information System (INIS)

Isotani, S.; Fujii, A.T.; Antonini, R.; Pontuschka, W.M.; Rabani, S.R.; Furtado, W.W.

1990-02-01

A comparative study is made of the luminescence of five kinds of spodumene from Minas Gerais, Brazil, studied previously by optical absorption spectroscopy. Natural gemstones are used which, in the course of the experiments, were irradiated with X-rays. (L.C.) [pt

Silicon: electrochemistry and luminescence

NARCIS (Netherlands)

Kooij, Ernst Stefan

1997-01-01

The electrochemistry of crystalline and porous silicon and the luminescence from porous silicon has been studied. One chapter deals with a model for the anodic dissolution of silicon in HF solution. In following chapters both the electrochemistry and various ways of generating visible

Biosynthesis of myristic acid in luminescent bacteria

International Nuclear Information System (INIS)

Byers, D.M.

1987-01-01

In vivo pulse-label studies have demonstrated that luminescent bacteria can provide myritic acid (14:0) required for the synthesis of the luciferase substrate myristyl aldehyde. Luminescent wild type Vibrio harveyi incubated with [ 14 C] acetate in a nutrient-depleted medium accumulated substantial tree [ 14 C]fatty acid (up to 20% of the total lipid label). Radio-gas chromatography revealed that > 75% of the labeled fatty acid is 14:0. No free fatty acid was detected in wild type cells labeled prior to the development of bioluminescence in the exponential growth phase, or in a dark mutant of V. harveyi (mutant M17) that requires exogenous 14:0 for light emission. The preferential accumulation of 14:0 was not observed when wild type cells were labeled with [ 14 C]acetate in regular growth medium. Moreover, all V. harveyi strains exhibited similar fatty acid mass compositions regardless of the state of bioluminescence. Since earlier work has shown that a luminescence-related acyltransferase (defective in the M17 mutant) can catalyze the deacylation of fatty acyl-acyl carrier protein in vitro, the present results are consistent with a model in which this enzyme diverts 14:0 to the luminescence system during fatty acid biosynthesis. Under normal conditions, the supply of 14:0 by this pathway is tightly regulated such that bioluminescence development does not significantly alter the total fatty acid composition

Conversion of the luminescence of laser dyes in opal matrices to stimulated emission

International Nuclear Information System (INIS)

Alimov, O K; Basiev, T T; Orlovskii, Yu V; Osiko, V V; Samoilovich, M I

2008-01-01

The luminescence and laser characteristics of a synthetic opal matrix filled with organic dyes are studied upon excitation by nanosecond laser pulses. The appearance of stimulated emission in a partially ordered scattering medium is investigated. It is shown that if the luminescence spectrum of a dye (oxazine-17) is located far outside the photonic bandgap of the opal matrix, stimulated emission along a preferential direction in the (111) plane is observed when pumping exceeds a threshold even without an external optical cavity. The stimulated emission spectrum is considerably narrower than the luminescence spectrum and consists of several narrow lines located within the dye luminescence band. If the luminescence spectrum of a dye (rhodamine 6G) overlaps with the photonic bandgap of the opal matrix, a different picture is observed. The loss of radiation in the matrix leads to the red shift of the luminescence spectrum, while the stimulated emission as in the case of oxazine-17 lies is observed within the luminescence band. (active media, lasers, and amplifiers)

Time-resolved luminescence studies in hydrogen uranyl phosphate intercalated with amines

Energy Technology Data Exchange (ETDEWEB)

Novo, Joao Batista Marques [Departamento de Quimica, Universidade Federal do Parana, CP 19081, 81531-990 Curitiba-PR (Brazil)]. E-mail: jbmnovo@quimica.ufpr.br; Batista, Fabio Roberto [Departamento de Quimica, Universidade Federal do Parana, CP 19081, 81531-990 Curitiba-PR (Brazil); Cunha, Carlos Jorge da [Departamento de Quimica, Universidade Federal do Parana, CP 19081, 81531-990 Curitiba-PR (Brazil); Dias, Lauro Camargo Jr. [Departamento de Quimica, Universidade Federal do Parana, CP 19081, 81531-990 Curitiba-PR (Brazil); Teixeira Pessine, Francisco Benedito [Instituto de Quimica, Universidade Estadual de Campinas, CP 6154, 13084-971 Campinas-SP (Brazil)

2007-05-15

Time-resolved luminescence decays of intercalated compounds of hydrogen uranyl phosphate (HUP) with p-toluidinium (HUPPT), benzylaminium (HUPBZ), {alpha}-methylbenzylaminium (HUPMBZ) and hydroxylaminium (HUPHAM) were studied. The prepared compounds belong to the tetragonal P4/ncc space group and showed 00 l reflections shifted to lower angles relative to HUP, indicating that the intercalation increases the c parameter of the unit cell. The luminescence decays of the compounds with 100% of intercalation ratio (HUPHAM and HUPBZ) were analyzed by Global Analysis, assuming Lianos' stretched exponential as the model function, which can be applied to compounds with restricted geometry and mobile donor and quencher molecules. It was remarkable that the luminescence decays showed that the quenching of the emission of the uranyl ions by the intercalated protonated amines is not restricted by low dimensionality of the host uranyl phosphate, and that a diffusion mechanism occurs. Benzylaminium cation efficiently quenches the excited energy of the uranyl ions at close distance, but the long-range and long-lifetime quenching is hindered. A different situation is found in the case of the small hydroxylaminium cation, where the long distance diffusion of the species is fast, playing an important role in the quenching of the excited uranyl ions at longer times.

Time-resolved luminescence studies in hydrogen uranyl phosphate intercalated with amines

International Nuclear Information System (INIS)

Novo, Joao Batista Marques; Batista, Fabio Roberto; Cunha, Carlos Jorge da; Dias, Lauro Camargo Jr.; Teixeira Pessine, Francisco Benedito

2007-01-01

Time-resolved luminescence decays of intercalated compounds of hydrogen uranyl phosphate (HUP) with p-toluidinium (HUPPT), benzylaminium (HUPBZ), α-methylbenzylaminium (HUPMBZ) and hydroxylaminium (HUPHAM) were studied. The prepared compounds belong to the tetragonal P4/ncc space group and showed 00 l reflections shifted to lower angles relative to HUP, indicating that the intercalation increases the c parameter of the unit cell. The luminescence decays of the compounds with 100% of intercalation ratio (HUPHAM and HUPBZ) were analyzed by Global Analysis, assuming Lianos' stretched exponential as the model function, which can be applied to compounds with restricted geometry and mobile donor and quencher molecules. It was remarkable that the luminescence decays showed that the quenching of the emission of the uranyl ions by the intercalated protonated amines is not restricted by low dimensionality of the host uranyl phosphate, and that a diffusion mechanism occurs. Benzylaminium cation efficiently quenches the excited energy of the uranyl ions at close distance, but the long-range and long-lifetime quenching is hindered. A different situation is found in the case of the small hydroxylaminium cation, where the long distance diffusion of the species is fast, playing an important role in the quenching of the excited uranyl ions at longer times

Splitting of the luminescent excited state of the uranyl ion

International Nuclear Information System (INIS)

Flint, C.D.; Sharma, P.; Tanner, P.A.

1982-01-01

The luminescence spectra of some uranyl compounds has been studied. It has been proposed that the splitting of the luminescent excited state of the uranyl ion is due to a descent in symmetry experienced by the uranyl ion when it is placed in a crystal field. In recent years there has been developed a highly successful model of the electronic structure of the uranyl ion. In this paper the authors use this model to interpret the luminescence spectra of a variety of uranyl compounds

Sensitive luminescent determination of DNA using the terbium(III)-difloxacin complex

International Nuclear Information System (INIS)

Yegorova, Alla V.; Scripinets, Yulia V.; Duerkop, Axel; Karasyov, Alexander A.; Antonovich, Valery P.; Wolfbeis, Otto S.

2007-01-01

The interaction of the terbium-difloxacin complex (Tb-DFX) with DNA has been examined by using UV-vis absorption and luminescence spectroscopy. The Tb-DFX complex shows an up to 85-fold enhancement of luminescence intensity upon titration with DNA. The long decay times allow additional detection schemes like time-resolved measurements in microplate readers to enhance sensitivity by off-gating short-lived background luminescence. Optimal conditions are found at equimolar concentrations of Tb 3+ and DFX (0.1 or 1 μM) at pH 7.4. Under these conditions, the luminescence intensity is linearly dependent on the concentration of ds-DNAs and ss-DNA between 1-1500 ng mL -1 and 4.5-270 ng mL -1 , respectively. The detection limit is 0.5 ng mL -1 for ds-DNAs and 2 ng mL -1 for ss-DNA. The mechanism for the luminescence enhancement was also studied

Comparison of Glaciological and Gravimetric Glacier Mass Balance Measurements of Taku and Lemon Creek Glaciers, Southeast Alaska

Science.gov (United States)

Vogler, K.; McNeil, C.; Bond, M.; Getraer, B.; Huxley-Reicher, B.; McNamara, G.; Reinhardt-Ertman, T.; Silverwood, J.; Kienholz, C.; Beedle, M. J.

2017-12-01

Glacier-wide annual mass balances (Ba) have been calculated for Taku (726 km2) and Lemon Creek glaciers (10.2 km2) since 1946 and 1953 respectively. These are the longest mass balance records in North America, and the only Ba time-series available for Southeast Alaska, making them particularly valuable for the global glacier mass balance monitoring network. We compared Ba time-series from Taku and Lemon Creek glaciers to Gravity Recovery and Climate Experiment (GRACE) mascon solutions (1352 and 1353) during the 2004-2015 period to assess how well these gravimetric solutions reflect individual glaciological records. Lemon Creek Glacier is a challenging candidate for this comparison because it is small compared to the 12,100 km2 GRACE mascon solutions. Taku Glacier is equally challenging because its mass balance is stable compared to the negative balances dominating its neighboring glaciers. Challenges notwithstanding, a high correlation between the glaciological and gravimetrically-derived Ba for Taku and Lemon Creek glaciers encourage future use of GRACE to measure glacier mass balance. Additionally, we employed high frequency ground penetrating radar (GPR) to measure the variability of accumulation around glaciological sites to assess uncertainty in our glaciological measurements, and the resulting impact to Ba. Finally, we synthesize this comparison of glaciological and gravimetric mass balance solutions with a discussion of potential sources of error in both methods and their combined utility for measuring regional glacier change during the 21st century.

Novel and easy access to highly luminescent Eu and Tb doped ultra-small CaF2, SrF2 and BaF2 nanoparticles - structure and luminescence.

Science.gov (United States)

Ritter, Benjamin; Haida, Philipp; Fink, Friedrich; Krahl, Thoralf; Gawlitza, Kornelia; Rurack, Knut; Scholz, Gudrun; Kemnitz, Erhard

2017-02-28

A universal fast and easy access at room temperature to transparent sols of nanoscopic Eu 3+ and Tb 3+ doped CaF 2 , SrF 2 and BaF 2 particles via the fluorolytic sol-gel synthesis route is presented. Monodisperse quasi-spherical nanoparticles with sizes of 3-20 nm are obtained with up to 40% rare earth doping showing red or green luminescence. In the beginning luminescence quenching effects are only observed for the highest content, which demonstrates the unique and outstanding properties of these materials. From CaF 2 :Eu10 via SrF 2 :Eu10 to BaF 2 :Eu10 a steady increase of the luminescence intensity and lifetime occurs by a factor of ≈2; the photoluminescence quantum yield increases by 29 to 35% due to the lower phonon energy of the matrix. The fast formation process of the particles within fractions of seconds is clearly visualized by exploiting appropriate luminescence processes during the synthesis. Multiply doped particles are also available by this method. Fine tuning of the luminescence properties is achieved by variation of the Ca-to-Sr ratio. Co-doping with Ce 3+ and Tb 3+ results in a huge increase (>50 times) of the green luminescence intensity due to energy transfer Ce 3+ → Tb 3+ . In this case, the luminescence intensity is higher for CaF 2 than for SrF 2 , due to a lower spatial distance of the rare earth ions.

A luminescent nisin biosensor

Science.gov (United States)

Immonen, Nina; Karp, Matti

2006-02-01

Nisin is a lantibiotic, an antibacterial peptide produced by certain Lactococcus lactis strains that kills or inhibits the growth of other bacteria. Nisin is widely used as a food preservative, and its long-time use suggests that it can be generally regarded as safe. We have developed a method for determining the amount of nisin in food samples that is based on luminescent biosensor bacteria. Bacterial luciferase operon luxABCDE was inserted into plasmid pNZ8048, and the construct was transformed by electroporation into Lc. lactis strain NZ9800, whose ability to produce nisin has been erased by deletion of the gene nisA. The operon luxABCDE has been modified to be functional in gram-positive bacteria to confer a bioluminescent phenotype without the requirement of adding an exogenous substrate. In the plasmid pNZ8048, the operon was placed under control of the nisin-inducible nisA promoter. The chromosomal nisRK genes of Lc. lactis NZ9800 allow it to sense nisin in the environment and relay this signal via signal transduction proteins NisK and NisR to initiate transcription from nisA promoter. In the case of our sensor bacteria, this leads to production of luciferase and, thus, luminescence that can be directly measured from living bacteria. Luminescence can be detected as early as within minutes of induction. The nisin assay described here provides a detection limit in the sub-picogram level per ml, and a linear area between 1 - 1000 pg/ml. The sensitivity of this assay exceeds the performance of all previously published methods.

AgesGalore-A software program for evaluating spatially resolved luminescence data

International Nuclear Information System (INIS)

Greilich, S.; Harney, H.-L.; Woda, C.; Wagner, G.A.

2006-01-01

Low-light luminescence is usually recorded by photomultiplier tubes (PMTs) yielding integrated photon-number data. Highly sensitive CCD (charged coupled device) detectors allow for the spatially resolved recording of luminescence. The resulting two-dimensional images require suitable software for data processing. We present a recently developed software program specially designed for equivalent-dose evaluation in the framework of optically stimulated luminescence (OSL) dating. The software is capable of appropriate CCD data handling, parameter estimation using a Bayesian approach, and the pixel-wise fitting of functions for time and dose dependencies to the luminescence signal. The results of the fitting procedure and the equivalent-dose evaluation can be presented and analyzed both as spatial and as frequency distributions

Monocrystalline silicon photovoltaic luminescent solar concentrator with 4.2% power conversion efficiency

NARCIS (Netherlands)

Desmet, L.; Ras, A.J.M.; Boer, de D.K.G.; Debije, M.G.

2012-01-01

We report conversion efficiencies of experimental single and dual light guide luminescent solar concentrators. We have built several 5¿¿cm×5¿¿cm and 10¿¿cm×10¿¿cm luminescent solar concentrator (LSC) demonstrators consisting of c-Si photovoltaic cells attached to luminescent light guides of Lumogen

Gravimetric model of the Gastre trough, province of Chubut, Argentina; Modelo gravimetrico en la fosa de Gastre, provincia de Chubut, Argentina

Energy Technology Data Exchange (ETDEWEB)

Lince Klinger, F.; Nacif, S.; Martinez, M. P.; Gimenez, M. E.; Ruiz, F.; Alvarez, O.

2011-07-01

A gravimetric study of the Gastre trough in the Province of Chubut, to the southwest of the Canadon Asfalto basin, has allowed us to determine the geometry of its crystalline basement. Using filtering techniques we were able to map residual Bouguer anomalies, which show the heterogeneities situated within the upper crust, some of which are linked to recognised geological structures. The gravimetric minima in the residual Bouguer anomaly map are associated with graben-type basins, flanked by positive gravity values associated with alignments identified on the surface and with the overall topographic relief of the Gastre trough. After suitable treatment of the density values of the outcrops and seismic data we were able to construct a 2D density model, perpendicular to the trough, which indicated a depth of 3600 m. The importance of this study lies in the fact that it has been possible to arrive at a gravimetric characterization of the Gastre trough in the Canadon Asfalto basin sector, a potentially hydrocarbon-bearing area hitherto lacking in reliable data concerning its subsoil. (Author)

Luminescence from Ce in sol-gel SiO{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Kroon, R.E., E-mail: KroonRE@ufs.ac.za [Department of Physics, University of the Free State, IB51, Box 339, Bloemfontein 9300 (South Africa); Seed Ahmed, H.A.A.; Ntwaeaborwa, O.M. [Department of Physics, University of the Free State, IB51, Box 339, Bloemfontein 9300 (South Africa); Koao, L.F. [Department of Physics, University of the Free State (Qwaqwa Campus), Private Bag X13, Phuthaditjhaba 9866 (South Africa); Nagpure, I.M.; Gusowski, M.A. [Department of Physics, University of the Free State, IB51, Box 339, Bloemfontein 9300 (South Africa); Botha, J.R. [Department of Physics, Nelson Mandela Metropolitan University, Box 77000, Port Elizabeth 6031 (South Africa); Swart, H.C. [Department of Physics, University of the Free State, IB51, Box 339, Bloemfontein 9300 (South Africa)

2012-05-15

The sol-gel process provides an attractive low temperature alternative to the melt process for producing Ce-doped silica, but reports of the emission wavelength have not been consistent. In this paper, luminescence measurements using a variety of excitation methods, including cathodoluminescence not yet reported by other researchers, are compared and evaluated in the light of previously published data. Several papers report luminescence around 350 nm but emission near this wavelength was not found from our samples. This luminescence originates from Ce that has not yet been incorporated in the silica and is found in samples that have not undergone high temperature annealing. Our photoluminescence results from samples annealed in a reducing atmosphere suggest that emission from Ce incorporated in the silica lattice occurs near 455 nm, and some indication of the emission from Ce in amorphous clusters at 400 nm is also found. However, our results also confirm earlier indications that intrinsic defects in silica can create photoluminescence near both these wavelengths, which can make identification of the luminescence due to Ce difficult. Finally, it has been found that samples which have been annealed in air, and therefore display poor photoluminescence because most of the Ce occurs in the tetravalent form, are luminescent under electron beam excitation. It is suggested that during cathodoluminescence measurements Ce{sup 4+} ions capture electrons to form excited Ce{sup 3+} ions from which the luminescence originates.

Gravimetric and conductometric studies of the sedimentation kinetics in aqueous dispersions of kaoline

International Nuclear Information System (INIS)

Bulavyin, L.A.; Khrapatij, S.V.; Koval'chuk, V.Yi.; Klepko, V.V.; Lebovka, M.Yi.

2006-01-01

Using gravimetric and conductometric methods, the sedimentation kinetics in aqueous suspensions of Alekseev kaoline has been studied for pH value range from 4 to 10. It has been found that pH increasing leads to the decreasing of mean radii of flocks linearly. We found that sedimentation kinetics for intermediate pH values can be described by scaling equations that crossover time defined transition from a gravitational mechanism of deposition to the diffusion one

X-ray micro-modulated luminescence tomography (XMLT)

Science.gov (United States)

Cong, Wenxiang; Liu, Fenglin; Wang, Chao; Wang, Ge

2014-01-01

Imaging depth of optical microscopy has been fundamentally limited to millimeter or sub-millimeter due to strong scattering of light in a biological sample. X-ray microscopy can resolve spatial details of few microns deep inside a sample but contrast resolution is inadequate to depict heterogeneous features at cellular or sub-cellular levels. To enhance and enrich biological contrast at large imaging depth, various nanoparticles are introduced and become essential to basic research and molecular medicine. Nanoparticles can be functionalized as imaging probes, similar to fluorescent and bioluminescent proteins. LiGa5O8:Cr3+ nanoparticles were recently synthesized to facilitate luminescence energy storage with x-ray pre-excitation and subsequently stimulated luminescence emission by visible/near-infrared (NIR) light. In this paper, we propose an x-ray micro-modulated luminescence tomography (XMLT, or MLT to be more general) approach to quantify a nanophosphor distribution in a thick biological sample with high resolution. Our numerical simulation studies demonstrate the feasibility of the proposed approach. PMID:24663898

Gravimetric water distribution assessment from geoelectrical methods (ERT and EMI) in municipal solid waste landfill.

Science.gov (United States)

Dumont, Gaël; Pilawski, Tamara; Dzaomuho-Lenieregue, Phidias; Hiligsmann, Serge; Delvigne, Frank; Thonart, Philippe; Robert, Tanguy; Nguyen, Frédéric; Hermans, Thomas

2016-09-01

The gravimetric water content of the waste material is a key parameter in waste biodegradation. Previous studies suggest a correlation between changes in water content and modification of electrical resistivity. This study, based on field work in Mont-Saint-Guibert landfill (Belgium), aimed, on one hand, at characterizing the relationship between gravimetric water content and electrical resistivity and on the other hand, at assessing geoelectrical methods as tools to characterize the gravimetric water distribution in a landfill. Using excavated waste samples obtained after drilling, we investigated the influences of the temperature, the liquid phase conductivity, the compaction and the water content on the electrical resistivity. Our results demonstrate that Archie's law and Campbell's law accurately describe these relationships in municipal solid waste (MSW). Next, we conducted a geophysical survey in situ using two techniques: borehole electromagnetics (EM) and electrical resistivity tomography (ERT). First, in order to validate the use of EM, EM values obtained in situ were compared to electrical resistivity of excavated waste samples from corresponding depths. The petrophysical laws were used to account for the change of environmental parameters (temperature and compaction). A rather good correlation was obtained between direct measurement on waste samples and borehole electromagnetic data. Second, ERT and EM were used to acquire a spatial distribution of the electrical resistivity. Then, using the petrophysical laws, this information was used to estimate the water content distribution. In summary, our results demonstrate that geoelectrical methods represent a pertinent approach to characterize spatial distribution of water content in municipal landfills when properly interpreted using ground truth data. These methods might therefore prove to be valuable tools in waste biodegradation optimization projects. Copyright © 2016 Elsevier Ltd. All rights reserved.

Luminescence properties of isomeric and tautomeric lanthanide pyridinedicarboxylates

International Nuclear Information System (INIS)

Puntus, L.N.; Zolin, V.F.; Babushkina, T.A.; Kutuza, I.B.

2004-01-01

The luminescence and PMR spectra of europium salts of six isomers of 2,3-, 2,4-, 2,5-, 2,6-, 3,4-, and 3,5-pyridinedicarboxylic acids (PDA) had been studied. The distribution of the effective charge in the nearest surroundings of the Eu 3+ ion in these salts was evaluated from Stark splittings of electronic transitions. The values of relative integral intensities of electronic transitions 5 D 0 - 7 F J (J=0-4) in the luminescence spectra were reported. Compounds investigated were divided into three subgroups taking into account the details of the structure of the ligands and details of the luminescence spectra. The ligand coordination manners as well as the strength of interaction between lanthanide ion and ligands were confirmed by data of the PMR and IR spectroscopy

Lanthanide-doped luminescent nanomaterials from fundamentals to bioapplications

CERN Document Server

Chen, Xueyuan; Tu, Datao

2014-01-01

Lanthanide-Doped Luminescent Nanomaterials reviews the latest advances in the development of lanthanide-doped luminescent inorganic nanoparticles for potential bioapplications. This book covers the chemical and physical fundamentals of these nanoparticles, such as the controlled synthesis methodology, surface modification chemistry, optical physics, and their promising applications in diverse bioassays, with an emphasis on heterogeneous and homogeneous in-vitro biodetection of tumor biomarkers. This book is intended for those readers who are interested in systematically understanding the materials design strategy, optical behavior of lanthanide ions, and practical bioapplications of lanthanide nanoparticles. It primarily focuses on the interdisciplinary frontiers in chemistry, physics and biological aspects of luminescent nanomaterials. All chapters were written by scientists active in this field and for a broad audience, providing both beginners and advanced researchers with comprehensive information on the ...

Gravimetric Measurements of Filtering Facepiece Respirators Challenged With Diesel Exhaust.

Science.gov (United States)

Satish, Swathi; Swanson, Jacob J; Xiao, Kai; Viner, Andrew S; Kittelson, David B; Pui, David Y H

2017-07-01

Elevated concentrations of diesel exhaust have been linked to adverse health effects. Filtering facepiece respirators (FFRs) are widely used as a form of respiratory protection against diesel particulate matter (DPM) in occupational settings. Previous results (Penconek A, Drążyk P, Moskal A. (2013) Penetration of diesel exhaust particles through commercially available dust half masks. Ann Occup Hyg; 57: 360-73.) have suggested that common FFRs are less efficient than would be expected for this purpose based on their certification approvals. The objective of this study was to measure the penetration of DPM through NIOSH-certified R95 and P95 electret respirators to verify this result. Gravimetric-based penetration measurements conducted using polytetrafluoroethylene (PTFE) and polypropylene (PP) filters were compared with penetration measurements made with a Scanning Mobility Particle Sizer (SMPS, TSI Inc.), which measures the particle size distribution. Gravimetric measurements using PP filters were variable compared to SMPS measurements and biased high due to adsorption of gas phase organic material. Relatively inert PTFE filters adsorbed less gas phase organic material resulting in measurements that were more accurate. To attempt to correct for artifacts associated with adsorption of gas phase organic material, primary and secondary filters were used in series upstream and downstream of the FFR. Correcting for adsorption by subtracting the secondary mass from the primary mass improved the result for both PTFE and PP filters but this correction is subject to 'equilibrium' conditions that depend on sampling time and the concentration of particles and gas phase hydrocarbons. Overall, the results demonstrate that the use of filters to determine filtration efficiency of FFRs challenged with diesel exhaust produces erroneous results due to the presence of gas phase hydrocarbons in diesel exhaust and the tendency of filters to adsorb organic material. Published by

Luminescence from potassium feldspars stimulated by infrared and green light

DEFF Research Database (Denmark)

Duller, G.A.T.; Bøtter-Jensen, L.

1993-01-01

A series of experiments are reported which investigate stimulated luminescence from potassium feldspar. The aim is to provide a basic phenomenological description of the response of the material to stimulation by heat, infrared radiation (875 DELTA 80 nm) and a green light wavelength band from 5 15...... to 560 nm. Two conclusions are drawn: firstly it is suggested that the majority of the trapped charge responsible for the infrared stimulated luminescence signal does not give rise to a thermoluminescence signal, and secondly that a large traction of the two optically stimulated luminescence signals...

On the half-life of luminescence signals in dosimetric applications: A unified presentation

Science.gov (United States)

Pagonis, V.; Kitis, G.; Polymeris, G. S.

2018-06-01

Luminescence signals from natural and man-made materials are widely used in dosimetric and dating applications. In general, there are two types of half-lives of luminescence signals which are of importance to experimental and modeling work in this research area. The first type of half-life is the time required for the population of the trapped charge in a single trap to decay to half its initial value. The second type of half-life is the time required for the luminescence intensity to drop to half of its initial value. While there a handful of analytical expressions available in the literature for the first type of half-life, there are no corresponding analytical expressions for the second type. In this work new analytical expressions are derived for the half-life of luminescence signals during continuous wave optical stimulation luminescence (CW-OSL) or isothermal luminescence (ITL) experiments. The analytical expressions are derived for several commonly used luminescence models which are based on delocalized transitions involving the conduction band: first and second order kinetics, empirical general order kinetics (GOK), mixed order kinetics (MOK) and the one-trap one-recombination center (OTOR) model. In addition, half-life expressions are derived for a different type of luminescence model, which is based on localized transitions in a random distribution of charges. The new half-life expressions contain two parts. The first part is inversely proportional to the thermal or optical excitation rate, and depends on the experimental conditions and on the cross section of the relevant luminescence process. The second part is characteristic of the optical and/or thermal properties of the material, as expressed by the parameters in the model. A new simple and quick method for analyzing luminescence signals is developed, and examples are given of applying the new method to a variety of dosimetric materials. The new test allows quick determination of whether a set of

Integrated light in direct excitation and energy transfer luminescence

OpenAIRE

Chimczak, Eugeniusz

2007-01-01

Integrated light in direct excitation and energy transfer luminescence has been investigated. In the investigations reported here, monomolecular centers were taken into account. It was found that the integrated light is equal to the product of generation rate and time of duration of excitation pulse for both direct excitation and energy transfer luminescence.

Investigations on vertical crustal movements in the Venezuelan Andes by gravimetric methods

Science.gov (United States)

Drewes, H.

1978-01-01

A precise gravimetric network has been installed in the Venezuelan Andes to study eventual gravity changes due to vertical tectonic movements. The design and the measurements of the network are described and the accuracy is estimated. In the center of the region a local gravity network has been reobserved three times. The detected variations are discussed. In order to obtain a genuine statement as far as possible about the significance of observed gravity changes, requirements for the procedure of monitoring precise gravity networks are pointed out.

Hydrological characterisation of stalagmite dripwaters at Grotte de Villars, Dordogne, by the analysis of inorganic species and luminescent organic matter

Directory of Open Access Journals (Sweden)

A. Baker

2000-01-01

Full Text Available Five stalagmite drip-waters in the Grotte de Villars, Dordogne, have been monitored from early 1997 to early 1998, for variations in discharge, major inorganic species and dissolved luminescent organic matter. When compared to surface precipitation, each drip-water has a subtly different response, both in terms of discharge variability and lag time between surface precipitation and drip rate response. Calculated water excess is shown to be important in determining drip-water discharge; during periods of soil moisture deficit, drip-waters either show no response to surface precipitation, or in the case of one sample station, respond only to high intensity and/or high quantity precipitation events. All drip-waters have a large storage component to their flow. Four sample stations have a similar hydrochemical and luminescence response, although the precise timing and magnitude of the responses may vary between drip sources that are Drip-water conductivity reflects Ca-HCO3 variations and falls during late summer to autumn, which is inferred to result from increased calcite precipitation above the cave with enhanced degassing related to progressive drying of the aquifer. Drip-water magnesium (following removal of the marine aerosol component is just above detection limits and does not show strong seasonal variations. Variations in solution Pco2 occur, with a particularly strong increase in early 1997. The various chemical trends are observed at a number of different sites despite a pronounced variation between them in terms of total Ca-HCO3 mineralisation and Pco2. One sampling station of the five investigated had a different response to surface precipitation; drip discharge was more variable, with evidence of non-linear responses, and luminescence intensity exhibited a dilution response to drip rate. For this site, flow switching occurred at times of high rainfall, with a rapid discharge response less than 24 hours after rainfall. Luminescence

Thermal quenching of luminescence processes in feldspars

DEFF Research Database (Denmark)

Poolton, N.R.J.; Bøtter-Jensen, L.; Duller, G.A.T.

1995-01-01

, which display very different behaviour. The first involves the internal transitions of common transition metal ions. The second is typical of centres not displaying excited states within the band gap that are likely to arise from direct recombination between the conduction band and the ground state......The technique of optically stimulated luminescence has important uses in the dose evaluation of irradiated feldspars. The luminescence process involves the eviction of electrons from donor traps, charge transfer through the conduction band, and recombination at acceptor sites; each...

A luminescence lifetime assisted ratiometric fluorimeter for biological applications

Science.gov (United States)

Lam, Hung; Kostov, Yordan; Rao, Govind; Tolosa, Leah

2009-12-01

In general, the most difficult task in developing devices for fluorescence ratiometric sensing is the isolation of signals from overlapping emission wavelengths. Wavelength discrimination can be achieved by using monochromators or bandpass filters, which often lead to decreased signal intensities. The result is a device that is both complex and expensive. Here we present an alternative system—a low-cost standalone optical fluorimeter based on luminescence lifetime assisted ratiometric sensing (LARS). This paper describes the principle of this technique and the overall design of the sensor device. The most significant innovation of LARS is the ability to discriminate between two overlapping luminescence signals based on differences in their luminescence decay rates. Thus, minimal filtering is required and the two signals can be isolated despite significant overlap of luminescence spectra. The result is a device that is both simple and inexpensive. The electronic circuit employs the lock-in amplification technique for the signal processing and the system is controlled by an onboard microcontroller. In addition, the system is designed to communicate with external devices via Bluetooth.

Tetranuclear cluster-based Pb(II)-MOF: Synthesis, crystal structure and luminescence sensing for CS2

Science.gov (United States)

Dong, Yanli

2018-05-01

A new Pb(II) coordination polymer, namely [Pb2(bptc)(DMA)]n (1, H4bptc = biphenyl-3,3‧,5,5‧-tetracarboxylic acid, DMA = N, N‧- dimethylacetamide), has been synthesized by the combination of H4bptc with Pb(NO3)2 under solvothermal conditions. Single crystal X-ray diffraction analysis revealed that compound 1 features a 3D framework based on tetranuclear [Pb4(COO)6] subunits, and topological analysis revealed that compound represents a binodal (4, 8)-connected scu-type topological network with the point symbol of {416,612}{44,62}2. Luminescence studies indicated that 1 and 1' (1‧ represents the desolvated samples) showed intense yellow emissions. Significantly, 1‧ exhibited sensitive luminescence sensing for CS2 solvent molecules at a low concentration.

LUMINESCENT PROPERTIES OF SILICATE GLASSES WITH CERIUM IONS AND ANTIMONY

Directory of Open Access Journals (Sweden)

A. M. Klykova

2014-05-01

Full Text Available The paper deals with the results of an experimental study of luminescence excitation spectra and luminescence of silicate glasses containing cerium ions and antimony. The aim of this work was to study the features of the luminescence and the effect of UV irradiation and heat treatment on luminescence and the state of cerium ions and antimony in glass. We investigated glass system Na2O-ZnO-Al2O3-SiO2-NaF-NaBr with additives CeO2 and Sb2O3. Synthesis was carried out in platinum crucibles in the air at 14500C. The samples were polished glass plates with a thickness of 0.5-1 mm. UV irradiation was carried out with a mercury lamp having a wide range of radiation in the spectral range 240-390 nm. It was conducted in a Nabertherm muffle furnaces. Luminescence spectra and excitation spectra were measured using a spectrofluorimeter MPF-44A (PerkinElmer at the room temperature. Measured luminescence spectra were corrected in view of the spectral sensitivity of the photodetector for spectrofluorimeter. Adjustment of the excitation spectra for the spectral dependence of the intensity of the excitation source was not carried out. During the experiments it was found that in silicate glasses Sb3+ ions can exist in two energy states, which corresponds to a different environment with oxygen ions. Heat treatment of these glasses in an oxidizing atmosphere leads to an increase in ion concentration of Sb3+ ions with a greater amount of oxygen in the environment. In glasses containing antimony and cerium ions, ultraviolet irradiation causes a change in the valence of cerium ions and antimony, which is accompanied by luminescence quenching. Subsequent heat treatment of glass leads to the inverse processes and restore luminescence excitation spectra. The study of fluorescent properties of silicate glasses with cerium and antimony ions led to the conclusion of the practical significance of this work. Promising multifunctional materials can be created on the basis of

Nanoscale luminescent lanthanide-based metal–organic frameworks: properties, synthesis, and applications

Energy Technology Data Exchange (ETDEWEB)

Hu, Dongqin; Song, Yonghai; Wang, Li, E-mail: lwanggroup@aliyun.com [Jiangxi Normal University, Key Laboratory of Functional Small Organic Molecule, Ministry of Education, Key Laboratory of Chemical Biology, Jiangxi Province, College of Chemistry and Chemical Engineering (China)

2015-07-15

Nanoscale luminescent lanthanide-based metal–organic frameworks (NLLn-MOFs) possess superior optical and physical properties such as higher luminescent lifetime, quantum yield, high stability, high surface area, high agent loading, and intrinsic biodegradability, and therefore are regarded as a novel generation of luminescent material compared with bulk lanthanide-based metal–organic frameworks (Ln-MOFs). Traditional luminescent Ln-MOFs have been well studied; however, NLLn-MOFs taking the advantages of nanomaterials have attracted extensive investigations for applications in optical imaging in living cells, light-harvesting, and sensing. In this review, we provide a survey of the latest progresses made in developing NLLn-MOFs, which contains the fundamental optical features, synthesis, and their potential applications. Finally, the future prospects and challenges of the rapidly growing field are summarized.

Unique Chiral Interpenetrating d-f Heterometallic MOFs as Luminescent Sensors.

Science.gov (United States)

Wu, Zhi-Lei; Dong, Jie; Ni, Wei-Yan; Zhang, Bo-Wen; Cui, Jian-Zhong; Zhao, Bin

2015-06-01

One novel three-dimensional (3D) 3d-4f metal-organic framework (MOF), [TbZn(L)(CO3)2(H2O)]n (1) [HL = 4'-(4-carboxyphenyl)-2,2':6',2″-terpyridine], has been successfully synthesized and structurally characterized. Structural analysis shows that compound 1 features a unique chiral interpenetrating 3D framework for the first time. The resulting crystals of 1 are composed of enantiomers 1a (P41) and 1b (P43), as was clearly confirmed by the crystal structure and the corresponding circular dichroism (CD) analyses of eight randomly selected crystals. The investigations on CD spectra based on every single crystal clearly assigned the Cotton effect signals. The powder X-ray diffraction measurement of 1 after being immersed in common solvents reveals that 1 possess excellent solvent stability. Furthermore, luminescent studies imply that 1 displays highly selective luminescent sensing of aldehydes, such as formol, acetaldehyde, and propanal.

Polysiloxane-based luminescent elastomers prepared by thiol-ene "click" chemistry.

Science.gov (United States)

Zuo, Yujing; Lu, Haifeng; Xue, Lei; Wang, Xianming; Wu, Lianfeng; Feng, Shengyu

2014-09-26

Side-chain vinyl poly(dimethylsiloxane) has been modified with mercaptopropionic acid, methyl 3-mercaptopropionate, and mercaptosuccinic acid. Coordinative bonding of Eu(III) to the functionalized polysiloxanes was then carried out and crosslinked silicone elastomers were prepared by thiol-ene curing reactions of these composites. All these europium complexes could be cast to form transparent, uniform, thin elastomers with good flexibility and thermal stability. The networks were characterized by FTIR, NMR, UV/Vis, and luminescence spectroscopy as well as by scanning electron microscopy, thermogravimetric analysis, and X-ray photoelectron spectroscopy. The europium elastomer luminophores exhibited intense red light at 617 nm under UV excitation at room temperature due to the (5)D0 →(7)F2 transition in Eu(III) ions. The newly synthesized luminescent materials offer many advantages, including the desired mechanical flexibility. They cannot be dissolved or fused, and so they have potential for use in optical and electronic applications. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Characterization and luminescent properties of thermally annealed olivines

International Nuclear Information System (INIS)

Colin-Garcia, Maria; Correcher, Virgilio; Garcia-Guinea, Javier; Heredia-Barbero, Alejandro; Roman-Lopez, Jesus; Ortega-Gutierrez, Fernando; Negron-Mendoza, Alicia; Ramos-Bernal, Sergio

2013-01-01

Olivine is an iron-magnesium solid solution silicate (Mg,Fe) 2 SiO 4 and it is probably one of the most abundant mineral phase in the Solar System, it is present in the primitive carbonaceous meteorites (i.e Allende), and in ordinary chondritic meteorite, comets or terrestrial planets. The olivine grains in those bodies have been exposed to different radiation sources like UV, electrons, cosmic radiation, etc. Here, we explore the effect of ionizing and non ionizing radiation on the luminescence emission of the two well-characterised olivine samples from Mexico and Spain by means of cathodoluminescence and thermoluminescence. The analyses by X-ray dispersive energies in the scanning electron microscopy show differences between the samples in the amount of iron and magnesium and also show traces of rare elements. Olivine exhibits spectral cathodoluminescence emissions of low intensity, explained for the quenching of the luminescence of the iron, and sharp signals assigned as impurities. Cathodoluminescence and thermoluminescence glow curves of the natural, and UV induced olivine samples were obtained. Our results show that thermal treatments at 1100 °C change the mineral molecular structure and the luminescence properties of this mineral phase. These results confirm an active participation of physical factors influencing the luminescent properties of olivine. -- Highlights: ► Luminescent properties of two olivines samples (Mexican and Spanish) were explored. ► EDS show different iron and magnesium content and traces of rare elements on both. ► Olivine exhibits spectral CL emissions of low intensity due to the quenching of iron. ► Treatments at 1100 °C change the mineral structure and its response to UV radiation

Real-time luminescence from Al2O3 fiber dosimeters

International Nuclear Information System (INIS)

Polf, J.C.; Yukihara, E.G.; Akselrod, M.S.; McKeever, S.W.S.

2004-01-01

The real-time luminescence signal from Al 2 O 3 single crystal fibers, monitored during simultaneous irradiation and optical stimulation, was investigated using computer simulations and experimental measurements. Both radioluminescence (RL) and optically stimulated luminescence (OSL) signals were studied. The simulations were performed initially using a simple one-trap/one-recombination-center energy band model, and then extended to include shallow and deep electron traps as well. Real-time luminescence experiments were performed for different radiation dose rates and optical stimulation powers using periodic laser stimulation of the samples through a fiber optic cable, and the experimental results were compared with the predictions from the computer simulations. The luminescence signal was observed, both theoretically and experimentally, to increase from its initial value to a steady-state level. The steady-state RL and OSL levels were found to be dependent on dose rate, the steady-state level of the real-time OSL being independent of laser power. It was also shown that the total integrated absorbed dose throughout the irradiation period can be determined by correcting the real-time OSL signal for depletion caused by each laser stimulation pulse. The effects of the shallow and deep traps on the time-dependence of the real-time luminescence signal were studied comparing the experimental data from several Al 2 O 3 fibers known to have different trapping state concentrations. The additional traps were found to slow the response of the real-time luminescence such that the time to reach steady state was increased as the additional traps were added

Scintillation and optical stimulated luminescence of Ce-doped CaF2

International Nuclear Information System (INIS)

Yanagida, Takayuki; Fujimoto, Yutaka; Watanabe, Kenichi; Fukuda, Kentaro; Kawaguchi, Noriaki; Miyamoto, Yuka; Nanto, Hidehito

2014-01-01

Scintillation and optical stimulated luminescence of Ce 0.1–20% doped CaF 2 crystals prepared by Tokuyama Corp. were investigated. In X-ray induced scintillation spectra, luminescence due to Ce 3+ 5d–4f transition appeared around 320 nm with typically 40 ns decay time. By 241 Am 5.5 MeV α-ray irradiation, 0.1% doped one showed the highest scintillation light yield and the light yield monotonically decreased with Ce concentrations. Optically stimulated luminescence after X-ray irradiation was observed around 320 nm under 550 or 830 nm stimulation in all samples. As a result, intensities of optically stimulated luminescence were proportional to Ce concentrations. Consequently, scintillation and optically stimulated luminescence resulted to have a complementary relation in Ce-doped CaF 2 system. - Highlights: • Optical, scintillation, and OSL properties of Ce 0.1–20% doped CaF 2 were studied. • Scintillation light yield exhibited inverse proportionality to Ce concentrations. • OSL intensities showed proportionality to Ce concentrations. • Complementary relation of scintillation and OSL was experimentally confirmed

Determination of sulfate in thorium salts using gravimetric technique with previous thorium separation

International Nuclear Information System (INIS)

Silva, C.M. da; Pires, M.A.F.

1994-01-01

Available as short communication only. A simple analytical method to analyze sulfates in thorium salt, is presented. The method is based on the thorium separation as hydroxide. The gravimetric technique is used to analyze the sulfate in the filtered as barium sulfate. Using this method, the sulfate separation from thorium has been reach 99,9% yield, and 0,1% precision. This method is applied to thorium salts specifically thorium sulfate, carbonate and nitrate. (author). 5 refs, 2 tabs

The effect of thermal oxidation on the luminescence properties of nanostructured silicon.

Science.gov (United States)

Liu, Lijia; Sham, Tsun-Kong

2012-08-06

Herein is reported a detailed study of the luminescence properties of nanostructured Si using X-ray excited optical luminescence (XEOL) in combination with X-ray absorption near-edge structures (XANES). P-type Si nanowires synthesized via electroless chemical etching from Si wafers of different doping levels and porous Si synthesized using electrochemical method are examined under X-ray excitation across the Si K-, L(3,2) -, and O K-edges. It is found that while as-prepared Si nanostructures are weak light emitters, intense visible luminescence is observed from thermally oxidized Si nanowires and porous Si. The luminescence mechanism of Si upon oxidation is investigated by oxidizing nanostructured Si at different temperatures. Interestingly, the two luminescence bands observed show different response with the variation of absorption coefficient upon Si and O core-electron excitation in elemental silicon and silicon oxide. A correlation between luminescence properties and electronic structures is thus established. The implications of the finding are discussed in terms of the behavior of the oxygen deficient center (OCD) and non-bridging oxygen hole center (NBOHC). Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Study on the light-color mixing of rare earth luminescent materials for anti-counterfeiting application

Science.gov (United States)

Zhang, Jishu; Zhang, Yingzi; Tao, Jin; Zhu, Yanan

2018-04-01

In order to find out the light color mixing mechanism of rare earth luminescent materials used in anti-counterfeiting fibers, we prepared three kinds of rare earth luminescent materials according to RGB tri-primary color, and mixed it together to form different mixtures in certain proportion. The phase structures of the luminescent material monomers were measured by x-ray diffractometer. The photochromic properties of the luminescent materials were tested and analyzed by fluorescence spectrophotometer. The results show that the light color mixing was consistent with the blending principle of additive color, but not the same because of the photochromic properties of rare earth luminescent materials, and we explored the reasons in the light wavelength and intensity. It was found that the enhancement of the luminescence intensity of the mixture on account of the superimposing of luminescence.

Study of the luminescence properties of a natural amazonite

Energy Technology Data Exchange (ETDEWEB)

Correcher, V., E-mail: v.correcher@ciemat.es [CIEMAT, Av. Complutense 22, Madrid 28040 (Spain); Garcia-Guinea, J. [Museo Nacional de Ciencias Naturales, CSIC, C/Jose Gutierrez Abascal 2, Madrid 28006 (Spain)

2011-09-15

Most gemstones, being natural materials (silicates, carbonates, phosphates, etc.), exhibit luminescence emission. This property could be potentially employed for personal dosimetry in the case of radiation accident or radiological terrorism where conventional monitoring has not been established. We, herein, report on the thermoluminescence (TL), radioluminescence (RL) and infra-red stimulated luminescence (IRSL) response of a well-characterised natural amazonite (KAlSi{sub 3}O{sub 8}) that, due to its bright blue-green colour when polished, is used as a gemstone. The luminescence emission wavelengths, intensities and thermal kinetics of the amazonite luminescence curves reveal that the ultraviolet band measured on amazonite aliquots is similar to other common K-rich feldspars. On this basis, one can conclude (i) association between twinning and the UV-blue TL emission can be related to structural defects located in the twin-domain boundaries where ionic alkali-self-diffusion, irreversible water losses and irreversible dehydroxylation processes can be involved. (ii) Amazonite exhibits a complex structure with several planar defects (twinning and exsolution interphases which can hold hydroxyl groups, water molecules, etc.) and point defects (impurities, Na, Pb, Mn, etc.) that can act as luminescence centres, and in fact, green and red emissions are respectively associated with the presence of Mn and Fe impurities. Finally, (iv) the thermal stability tests performed on the TL emission of the amazonite confirm a continuum in the trap distribution, i.e. progressive changes in the glow curve shape, intensity and temperature position of the maximum peak.

The recombination channels of luminescence excitation in YAG:Yb single crystalline films

International Nuclear Information System (INIS)

Zakharko, Ya.M.; Luchechko, A.P.; Ubizskii, S.B.; Syvorotka, I.I.; Martynyuk, N.V.; Syvorotka, I.M.

2007-01-01

Absorption and emission spectra, luminescence decay kinetics and thermostimulated luminescence of X-ray irradiated YAG:Yb single crystalline films were studied. Two emission bands peaked at 420 and 488 nm have been detected in the investigated films. The strong thermal quenching of luminescence band at 488 nm was observed above 160 K. The influence of growth conditions and annealing in air on the lifetime of Yb 3+ ion excited state in the IR spectral region have been revealed. The recombination mechanisms of the f-f transition at Yb 3+ ion excitation, as well as the mechanism of lifetime shortening for the excited Yb 3+ luminescence have been discussed

Size-dependent abnormal thermo-enhanced luminescence of ytterbium-doped nanoparticles.

Science.gov (United States)

Cui, Xiangshui; Cheng, Yao; Lin, Hang; Huang, Feng; Wu, Qingping; Wang, Yuansheng

2017-09-21

Thermal quenching above 300 K is widely expected in photoluminescence. Luminescence quenching is usually ascribed to the non-radiative relaxation of excited electrons to the ground state of the activators, during which a high temperature always plays a role in pushing the excited electrons towards the quenching channels, leading to thermal quenching. For the lanthanide-doped nanoparticles, however, there is a special luminescence quenching channel that does not exist in their bulk counterparts, i.e., energy migration-induced surface quenching. Herein, a size-dependent abnormal thermal enhancement of luminescence in the temperature range of 300 K to 423 K in the ytterbium-doped fluoride nanoparticles is presented for the first time. Importantly, in this work, we originally demonstrate that the energy migration-induced surface quenching can be suppressed by increasing temperature, which results in the abnormal thermal enhancement of luminescence. According to the temperature-dependent X-ray diffraction and lifetime analyses, an underlying mechanism based on the effect of thermal lattice expansion on ytterbium-mediated energy migration is proposed. This new finding adds new insights to the size effect on the luminescent characteristics of nanoparticles, which could be utilized to construct some unique nanostructures, especially for many important temperature-related purposes, such as thermal sensing technology.

Iron control of the Vibrio fischeri luminescence system in Escherichia coli.

Science.gov (United States)

Dunlap, P V

1992-01-01

Iron influences luminescence in Vibrio fischeri; cultures iron-restricted for growth rate induce luminescence at a lower optical density (OD) than faster growing, iron-replete cultures. An iron restriction effect analogous to that in V. fischeri (slower growth, induction of luminescence at a lower OD) was established using Escherichia coli tonB and tonB+ strains transformed with recombinant plasmids containing the V. fischeri lux genes (luxR luxICDABEG) and grown in the presence and absence of the iron chelator ethylenediamine-di(o-hydroxylphenyl acetic acid) (EDDHA). This permitted the mechanism of iron control of luminescence to be examined. A fur mutant and its parent strain containing the intact lux genes exhibited no difference in the OD at induction of luminescence. Therefore, an iron-binding repressor protein apparently is not involved in iron control of luminescence. Furthermore, in the tonB and in tonB+ strains containing lux plasmids with Mu dI(lacZ) fusions in luxR, levels of beta-galactosidase activity (expression from the luxR promoter) and luciferase activity (expression from the luxICDABEG promoter) both increased by a similar amount (8-9 fold each for tonB, 2-3 fold each for tonB+) in the presence of EDDHA. Similar results were obtained with the luxR gene present on a complementing plasmid. The previously identified regulatory factors that control the lux system (autoinducer-LuxR protein, cyclic AMP-cAMP receptor protein) differentially control expression from the luxR and luxICDABEG promoters, increasing expression from one while decreasing expression from the other. Consequently, these results suggest that the effect of iron on the V. fischeri luminescence system is indirect.

Novel lanthanide doped micro- and mesoporous solids. Characterization of ion-host-interactions, species distribution and luminescence properties using time-resolved luminescence spectroscopy; Neuartige Lanthanoid-dotierte mikro- und mesoporoese Feststoffe. Charakterisierung von Ion-Wirt-Wechselwirkungen, Speziesverteilung und Lumineszenzeigenschaften mittels zeitaufgeloester Lumineszenzspektroskopie

Energy Technology Data Exchange (ETDEWEB)

Gessner, Andre

2010-12-15

In this work lanthanide-doped microporous zeolites, microporous-mesoporous hybrid materials and mesoporous silicates were investigated regarding their luminescence properties and the ion-host-interactions using time-resolved luminescence spectroscopy. Thereby, time-resolved emission spectra (TRES) provide information in the wavelength and time domain. For the analysis of the TRES a broad set of analytic methods was applied and thus a corresponding ''toolbox'' developed. Fitting of the luminescence decays was performed with a discrete number of exponentials and supported by luminescence decay times distributions. Time-resolved area normalized emission spectra (TRANES), an advancement of TRES, could be used for the determination of the number of emissive lanthanide species in porous materials for the first time. Calculation of the decay-associated spectra (DAS) allowed the correlation of spectral information with luminescence decay times and thus delivered the luminescence spectra of the different europium species. For europium(III) we could use in addition the time-dependent asymmetry ratio and spectral evolution of the {sup 5}D{sub 0}-{sup 7}F{sub 0}-transition with time to obtain further information about the distribution of the lanthanide ions in the host material. Luminescence decay times and spectra allowed conclusions on the number of OH-oscillators in and the symmetry of the first coordination sphere. For the microporous and microporous-mesoporous materials were found different lanthanide species, which were characterized by the above mentioned methods. These lanthanide species can be found on different positions in the host material. One position is located deep in the pore system. Here, lanthanide ions are hardly accessible for water and mainly coordinated by framework oxygens. This results in long luminescence decay times and distorted coordination spheres. The second position can be found near or on the outer surface or in the

Luminescence properties of KCl:Ag{sup -} crystals excited near the fundamental absorption edge

Energy Technology Data Exchange (ETDEWEB)

Kawai, Taketoshi, E-mail: buri@p.s.osakafu-u.ac.jp [Department of Physical Science, Graduate School of Science, Osaka Prefecture University, Gakuen-cho 1-1, Naka-ku, Sakai, Osaka 599-8531 (Japan); Hirai, Takeshi [Department of Physical Science, Faculty of Science and Engineering, Ritsumeikan University, Noji Higashi 1-1-1, Kusatsu, Shiga 525-8577 (Japan)

2012-02-15

Luminescence properties of KCl single crystals doped with Ag{sup -} centers have been investigated under various excitation energies around the fundamental absorption edge at low temperatures. Under the excitation at 6.89 eV, which is lower than the intrinsic exciton energy by 0.87 eV, the A Prime luminescence band due to the intraionic transition in the Ag{sup -} ion is dominantly observed at 2.91 eV. On the other hand, the excitation at 6.66 eV induces a broad luminescence band at 2.60 eV in addition to the A Prime luminescence band. From the comparison with the localized excitons in KCl:I crystals, the 2.60 eV luminescence band is attributed to the two-center type localized exciton related with the Ag{sup -} ion. The adiabatic potential energy surfaces of the excited states in the Ag{sup -} center and the localized exciton in KCl:Ag{sup -} are discussed. - Highlights: Black-Right-Pointing-Pointer We study the luminescence properties of KCl single crystals doped with Ag{sup -} ions. Black-Right-Pointing-Pointer The excitation around the absorption edge induces a broad luminescence at 2.60 eV. Black-Right-Pointing-Pointer The 2.60 eV luminescence is attributed to the exciton localized at the Ag{sup -} ion. Black-Right-Pointing-Pointer The localized exciton has the two-center type configuration of the relaxed exciton.

Simple and rapid measurement of α-rays on smear samples using air luminescence

International Nuclear Information System (INIS)

Takiue, M.

1980-01-01

The α-activity collected on smear samples has been measured indirectly using an air luminescence counting method and a liquid scintillation spectrometer. In this method, air luminescence, attributed to the fluorescence emitted by nitrogen molecules excited by α-rays in air, serves to detect α-rays. Thus, sample preparation and α-ray measurement are simple and rapid, and moreover, no radioactive waste solution is produced. Taking into account a low background and a counting efficiency between 10 and 20%, it is estimated that the detectable limit for α-ray measurement is about 1 x 10 -7 μCi/cm 2 for loose contamination. This method is convenient to use in the routine analysis of α-ray-emitting nuclides on smear paper. (author)

Luminescence evolution of porous GaN thin films prepared via UV-assisted electrochemical etching

International Nuclear Information System (INIS)

Cheah, S.F.; Lee, S.C.; Ng, S.S.; Yam, F.K.; Abu Hassan, H.; Hassan, Z.

2015-01-01

Porous gallium nitride (GaN) thin films with different surface morphologies and free carriers properties were fabricated from Si-doped GaN thin films using ultra-violet assisted electrochemical etching approach under various etching voltages. Fluctuation of luminescence signals was observed in the photoluminescence spectra of porous GaN thin films. Taking advantage of the spectral sensitivity of infrared attenuated total reflection spectroscopy on semiconductor materials, roles of free carriers and porous structure in controlling luminescence properties of GaN were investigated thoroughly. The results revealed that enhancement in luminescence signal is not always attained upon porosification. Although porosification is correlated to the luminescence enhancement, however, free carrier is the primary factor to enhance luminescence intensity. Due to unavoidable significant reduction of free carriers from Si-doped GaN in the porosification process, control of etching depth (i.e., thickness of porous layer formed from the Si-doped layer) is critical in fabricating porous GaN thin film with enhanced luminescence response. - Highlights: • Various pore morphologies with free carrier properties are produced by Si-doped GaN. • Free carriers are important to control the luminescence signal of porous GaN. • Enhancement of luminescence signal relies on the pore depth of Si-doped layer

Luminescence Properties of Self-Aggregating TbIII-DOTA-Functionalized Calix[4]arenes

Science.gov (United States)

Mayer, Florian; Tiruvadi Krishnan, Sriram; Schühle, Daniel T.; Eliseeva, Svetlana V.; Petoud, Stéphane; Tóth, Éva; Djanashvili, Kristina

2018-01-01

Self-aggregating calix[4]arenes carrying four DOTA ligands on the upper rim for stable complexation of paramagnetic GdIII-ions have already been proposed as MRI probes. In this work, we investigate the luminescence properties of TbIII-DOTA-calix[4]arene-4OPr containing four propyl-groups and compare them with those of the analogue substituted with a phthalimide chromophore (TbIII-DOTA-calix[4]arene-3OPr-OPhth). We show that, given its four aromatic rings, the calix[4]arene core acts as an effective sensitizer of Tb-centered luminescence. Substituents on the lower rim can modulate the aggregation behavior, which in turn determines the luminescence properties of the compounds. In solid state, the quantum yield of the phthalimide derivative is almost three times as high as that of the propyl-functionalized analogue demonstrating a beneficial role of the chromophore on Tb-luminescence. In solution, however, the effect of the phthalimide group vanishes, which we attribute to the large distance between the chromophore and the lanthanide, situated on the opposite rims of the calix[4]arene. Both quantum yields and luminescence lifetimes show clear concentration dependence in solution, related to the strong impact of aggregation on the luminescence behaviour. We also evidence the variability in the values of the critical micelle concentration depending on the experimental technique. Such luminescent calix[4]arene platforms accommodating stable lanthanide complexes can be considered valuable building blocks for the design of dual MR/optical imaging probes.

Determination of molybdenum by the gravimetric plumbate method (with the molybdenum content from 50 % and above)

International Nuclear Information System (INIS)

Stepin, V.V.; Kurbatova, V.I.; Fedorova, N.D.

1980-01-01

A gravimetric method of molybdenum determination in ferromolybdenum (Mo content from 50% and higher) after its dissolving in HNO 3 is developed. The method is based on Mo deposition in acetic acid solution in the form of molybdenum oxide lead after separation of Fe and other interfering elements with sodium hydroxide [ru

Thermally and optically stimulated luminescence of early medieval blue-green glass mosaics

Energy Technology Data Exchange (ETDEWEB)

Galli, A. E-mail: anna.galli@mater.unimib.it; Martini, M.; Montanari, C.; Sibilia, E

2004-12-01

The preliminary results of a study related to luminescent mechanisms in glass mosaic tesserae are presented. The samples came from a medieval glass deposit found during archaeological excavations in the S. Lorenzo Church in Milan. Energy Dispersive X-rays Fluorescence (EDXRF) measurements were performed to obtain information on the elemental composition of the materials. Thermally Stimulated Luminescence (TSL, both conventional and wavelength resolved) and Optically Stimulated Luminescence (OSL) analyses allowed to get information about traps and luminescence centres. The observed luminescence characteristics were close to that of quartz, showing the presence of an easy to bleach trap (300 deg. C, 1.95 eV) and of a hard to bleach trap (350 deg. C, 2.20 eV); charge transfer phenomena, involving the low-temperature peaks have been observed. There is a strong indication that the easy to bleach traps are responsible for both OSL and TSL emission at 300 deg. C.

Thermally and optically stimulated luminescence of early medieval blue-green glass mosaics

International Nuclear Information System (INIS)

Galli, A.; Martini, M.; Montanari, C.; Sibilia, E.

2004-01-01

The preliminary results of a study related to luminescent mechanisms in glass mosaic tesserae are presented. The samples came from a medieval glass deposit found during archaeological excavations in the S. Lorenzo Church in Milan. Energy Dispersive X-rays Fluorescence (EDXRF) measurements were performed to obtain information on the elemental composition of the materials. Thermally Stimulated Luminescence (TSL, both conventional and wavelength resolved) and Optically Stimulated Luminescence (OSL) analyses allowed to get information about traps and luminescence centres. The observed luminescence characteristics were close to that of quartz, showing the presence of an easy to bleach trap (300 deg. C, 1.95 eV) and of a hard to bleach trap (350 deg. C, 2.20 eV); charge transfer phenomena, involving the low-temperature peaks have been observed. There is a strong indication that the easy to bleach traps are responsible for both OSL and TSL emission at 300 deg. C

Optical stimulated luminescence (OSL) dating

International Nuclear Information System (INIS)

Banerjee, D.

1999-01-01

Since the pioneering work by Huntley et al. (1985), optical dating is being increasingly recognised as an important technique for establishing a time frame of deposition of sediments (Aitken, 1998). Optical dating differs from thermoluminescence (TL) dating in that visible/infrared light from lasers or LEDs (light-emitting-diodes) is used as a means of stimulation, in contrast to thermal stimulation. It has several advantages over TL dating: (i) the resetting of the OSL (optically stimulated luminescence) clock is more effective than that of TL clock; for sediments transported under water or in other situations where the sediment grains have undergone inhomogeneous bleaching, this property ensures that ages based on optical dating are generally more reliable than TL ages, (ii) the optical dating technique is non-destructive, and multiple readouts of the optical signal is possible; this feature has resulted in the development of single-aliquot and single-grain protocols (Murray and Wintle, 1999; Banerjee et al. 1999), (iii) the sample is not heated as in TL; thus, spurious luminescence is avoided and there is a significant reduction in blackbody radiation. Dating of materials which change phase on heating is also practical, and finally, (iv) thermal quenching of luminescence is negligible, allowing accurate estimation of kinetic parameters using standard techniques and providing access to deep OSL traps. This characteristic may be helpful in extending the limits of optical dating beyond the last 150 ka from a global point of view

An optically stimulated luminescence study of porcelain related to radiation dosimetry

DEFF Research Database (Denmark)

Poolton, N.R.J.; Bøtter-Jensen, L.; Jungner, H.

1995-01-01

Stokes and anti-Stokes shifted in energy. Glazing is shown in some cases to be considerably more sensitive as a radiation dosemeter than the main porcelain ceramic. By comparison with the properties of artifical phosphors, the principal luminescent matrix is identified as being Al2O3......This article describes the essential features regarding the photo-stimulated luminescence of porcelain: both the main ceramic and glazing materials are studied. In each case, radiation dose dependent signals are observed, superimposed on dose independent luminescence transitions that are both...

Determination of organophosphorus pesticides in water samples by using a new sensitive luminescent probe of Eu (III) complex

Energy Technology Data Exchange (ETDEWEB)

Azab, Hassan A., E-mail: azab2@yahoo.com; Anwar, Z.M.; Rizk, M.A.; Khairy, Gasser M.; El-Asfoury, M.H.

2015-01-15

This work describes the application of fluorescence for investigating the interactions of Eu(III)-TAN-1,10 phenanthroline (where TAN=4,4,4-Trifluoro-1-(2-naphthyl)-1,3-butanedione) with pesticides Chlorpyrifos, Malathion, Endosulfan, Heptachlor. The complex was synthesized and characterized by elemental analysis, FTIR, x-ray spectroscopy, solid fluorescence and thermal analysis. The results indicated that the composition of this complex is [Eu(TAN){sub 2}(Phen)(H{sub 2}O){sub 2}]Cl. The luminescence properties of the complex in different solvents and at different pH values have been investigated. The results show that the complex exhibits more efficient luminescence at pH=7.5. The interactions of Eu-complex with different pesticides (Chlorpyrifos, Malathion, Endosulfan, and Heptachlor) in aqueous medium have been investigated by fluorescence measurements. The luminescence intensity of the probe is quenched by Malathion and enhanced by (Endosulfan, Heptachlor, and Chlorpyrifos). Direct methods for the determination of the pesticides under investigation have been developed using the luminescence variations of the probe in solution. The detection limits are 0.47, 1.02, 0.66, 0.64 µmol/L for Chlorpyrifos, Endosulfan, Heptachlor, and Malathion, respectively. The binding constants and thermodynamic parameters of the pesticides with probe were evaluated. The emission quantum yield (QY=0.71) of Eu(III)-complex was determined using tris (2,2'-bipyridyl) dichlororuthenium(II) hexahydrate. A thermodynamic analysis showed that the reaction is spontaneous with negative ΔG. Effect of some relevant interferents on the detection of pesticides has been investigated. The new method was applied to the determination of the pesticides in different types of water samples (tap, river, and waste water). - Highlights: • A new luminescent probe of Eu (III) complex has been developed for sensing some organophosphorus pesticides. • Four guest pesticides Chlorpyrifos, Malathion

Determination of organophosphorus pesticides in water samples by using a new sensitive luminescent probe of Eu (III) complex

International Nuclear Information System (INIS)

Azab, Hassan A.; Anwar, Z.M.; Rizk, M.A.; Khairy, Gasser M.; El-Asfoury, M.H.

2015-01-01

This work describes the application of fluorescence for investigating the interactions of Eu(III)-TAN-1,10 phenanthroline (where TAN=4,4,4-Trifluoro-1-(2-naphthyl)-1,3-butanedione) with pesticides Chlorpyrifos, Malathion, Endosulfan, Heptachlor. The complex was synthesized and characterized by elemental analysis, FTIR, x-ray spectroscopy, solid fluorescence and thermal analysis. The results indicated that the composition of this complex is [Eu(TAN) 2 (Phen)(H 2 O) 2 ]Cl. The luminescence properties of the complex in different solvents and at different pH values have been investigated. The results show that the complex exhibits more efficient luminescence at pH=7.5. The interactions of Eu-complex with different pesticides (Chlorpyrifos, Malathion, Endosulfan, and Heptachlor) in aqueous medium have been investigated by fluorescence measurements. The luminescence intensity of the probe is quenched by Malathion and enhanced by (Endosulfan, Heptachlor, and Chlorpyrifos). Direct methods for the determination of the pesticides under investigation have been developed using the luminescence variations of the probe in solution. The detection limits are 0.47, 1.02, 0.66, 0.64 µmol/L for Chlorpyrifos, Endosulfan, Heptachlor, and Malathion, respectively. The binding constants and thermodynamic parameters of the pesticides with probe were evaluated. The emission quantum yield (QY=0.71) of Eu(III)-complex was determined using tris (2,2'-bipyridyl) dichlororuthenium(II) hexahydrate. A thermodynamic analysis showed that the reaction is spontaneous with negative ΔG. Effect of some relevant interferents on the detection of pesticides has been investigated. The new method was applied to the determination of the pesticides in different types of water samples (tap, river, and waste water). - Highlights: • A new luminescent probe of Eu (III) complex has been developed for sensing some organophosphorus pesticides. • Four guest pesticides Chlorpyrifos, Malathion, Endosulfan, and

Optical and luminescence properties of zinc oxide (Review)

Science.gov (United States)

Rodnyi, P. A.; Khodyuk, I. V.

2011-11-01

We generalize and systematize basic experimental data on optical and luminescence properties of ZnO single crystals, thin films, powders, ceramics, and nanocrystals. We consider and study mechanisms by which two main emission bands occur, a short-wavelength band near the fundamental absorption edge and a broad long-wavelength band, the maximum of which usually lies in the green spectral range. We determine a relationship between the two luminescence bands and study in detail the possibility of controlling the characteristics of ZnO by varying the maximum position of the short-wavelength band. We show that the optical and luminescence characteristics of ZnO largely depend on the choice of the corresponding impurity and the parameters of the synthesis and subsequent treatment of the sample. Prospects for using zinc oxide as a scintillator material are discussed. Additionally, we consider experimental results that are of principal interest for practice.

Optically stimulated luminescence dosimetry with gypsum wallboard (drywall)

International Nuclear Information System (INIS)

Thompson, J. W.; Burdette, K. E.; Inrig, E. L.; Dewitt, R.; Mistry, R.; Rink, W. J.; Boreham, D. R.

2010-01-01

Gypsum wallboard (drywall) represents an attractive target for retrospective dosimetry by optically stimulated luminescence (OSL) in the event of a radiological accident or malicious use of nuclear material. In this study, wallboard is shown to display a radiation-induced luminescence signal (RIS) as well as a natural background signal (NS), which is comparable in intensity to the RIS. Excitation and emission spectra show that maximum luminescence intensity is obtained for stimulation with blue light-emitting diodes (470 nm) and for detection in the ultraviolet region (290-370 nm). It is necessary to decrease the optical stimulation power dramatically in order to adequately separate the RIS from the interfering background signal. The necessary protocols are developed for accurately measuring the absorbed dose as low as 500 mGy and demonstrate that the RIS decays logarithmically with storage time, with complete erasure expected within 1-4 d. (authors)

Luminescent screens

International Nuclear Information System (INIS)

Lu, C.-I.

1982-01-01

Luminescent screens which are useful for such purposes as intensifying screens for radiographs are comprised of a support bearing a layer of finely divided particles of a phosphor dispersed in a cross-linked polymeric matrix formed by heat-curing of a coating composition comprising an unsaturated cross-linkable polymer, a polymerizable acrylic monomer, a thermoplastic polyurethane elastomer, and a heat-activatable polymerization initiator. The phosphor layer includes voids formed by evaporation of an evaporable component which is present in the coating composition from which such layer is formed. (author)

Synthesis of amorphous zirconium oxide with luminescent characteristics

International Nuclear Information System (INIS)

Barrera S, M.; Chavez G, M.; Soto E, A.M.; Velasquez O, C.; Garcia S, M.A.; Olvera T, L.; Rivera M, T.

2004-01-01

It was prepared zirconium oxide, ZrO 2 , by means of hydrolysis-condensation reactions (sol-gel method), using zirconium propoxide, Zr(C 3 H 7 O) 4 , as precursor and nitric acid, HNO 3 , as catalyst of the hydrolysis reaction. In this synthesis it was used a molar ratio water-alkoxide, r=n H2O /n Zr (C 3 H 7 0) 4 , high, similar to 200, so that the hydrolysis happens quickly and the nucleation and growth are completed in very little time. The solid was characterized with Ftir spectrophotometry, Differential thermal analysis (Dta), Thermal gravimetric analysis (T G), X-ray diffraction of powders, Scanning electron microscopy (Sem) and X-ray Dispersion energy (EDX). The ZrO 2 obtained by this way is amorphous even to 300 C and it consists of big aggregates. The amorphous ZrO 2 , presents thermoluminescent behavior, after it was irradiated with UV radiation and beta particles of 90 Sr/ 90 Y and it was thermally stimulated. (Author)

Dependence of the thermal influence on luminescence lifetimes from quartz on the duration of optical stimulation

International Nuclear Information System (INIS)

Chithambo, M.L.

2003-01-01

Time-resolved luminescence spectra may be measured from quartz at various stages of continuous optical stimulation in order to investigate properties of the spectra associated with the 'fast', 'medium', and 'slow' components of continuous optically stimulated luminescence (OSL). In this work, temperature related changes of luminescence lifetimes and luminescence intensity, both evaluated from time-resolved luminescence spectra recorded in the 'fast' 'medium' and 'slow' component regions of quartz OSL, have been investigated. The luminescence, stimulated at 525 nm, and measured at intervals between 20 deg. C and 200 deg. C reaches maximum intensity at 100 deg. C and decreases thereafter up to 200 deg. C, the maximum temperature of the investigations. Luminescence lifetimes, on the other hand, remain constant within 40±3 μs between 20 deg. C and 100 deg. C and then decrease down to about μs at 200 deg. C. The initial increase of luminescence intensity with temperature between 20 deg. C and 100 deg. C is discussed in terms of thermal assistance to luminescence stimulation. Beyond 100 deg. C, radiative recombination is affected by quenching of luminescence and reduction in luminescence lifetimes. The activation energy for thermal quenching was evaluated to be in the range 0.63±0.07 eV at all stimulation times and that of thermal assistance was evaluated to be about 0.06 eV for the 'fast' and 'medium' component regions and about 0.1 eV for the 'slow' component region of the OSL

Crack luminescence as an innovative method for detection of fatigue damage

Directory of Open Access Journals (Sweden)

R. Makris

2018-04-01

Full Text Available Conventional non-destructive testing methods for crack detection provide just a snapshot of fatigue crack evolution at a specific location in the moment of examination. The crack luminescence coating realizes a clear visibility of the entire crack formation. The coating consists of two layers with different properties and functions. The bottom layer emits light as fluorescence under UV radiation. The top layer covers the fluorescing one and prevents the emitting of light in case of no damage at the surface. Several different experiments show that due to the sensitive coating even the early stage of crack formation can be detected. That makes crack luminescence helpful for investigating the incipient crack opening behavior. Cracks can be detected and observed during operation of a structure, making it also very interesting for continuous monitoring. Crack luminescence is a passive method and no skilled professionals are necessary to detect cracks, as for conventional methods. The luminescent light is clearly noticeable by unaided eye observations and also by standard camera equipment, which makes automated crack detection possible as well. It is expected that crack luminescence can reduce costs and time for preventive maintenance and inspection.

Origin of green luminescence in hydrothermally grown ZnO single crystals

Energy Technology Data Exchange (ETDEWEB)

Čížek, J., E-mail: jakub.cizek@mff.cuni.cz; Hruška, P.; Melikhova, O.; Procházka, I. [Department of Low-Temperature Physics, Charles University in Prague, V Holešovičkách 2, CZ-180 00, Prague 8 (Czech Republic); Valenta, J. [Department of Chemical Physics and Optics, Charles University in Prague, Ke Karlovu 3, CZ-121 16, Prague 2 (Czech Republic); Novotný, M.; Bulíř, J. [Academy of Science of the Czech Republic, Institute of Physics, Na Slovance 2, CZ-182 21 Praha 8 (Czech Republic)

2015-06-22

Combining photoluminescence and positron annihilation studies of hydrothermally grown ZnO crystals with stoichiometry varied by controlled annealing enabled us to clarify the origin of green luminescence. It was found that green luminescence in ZnO has multiple origins and consists of a band at 2.3(1) eV due to recombination of electrons of the conduction band by zinc vacancy acceptors coupled with hydrogen and a band at 2.47(2) eV related to oxygen vacancies. The as-grown ZnO crystals contain zinc vacancies associated with hydrogen and exhibit a green luminescence at 2.3(1) eV. Annealing in Zn vapor removed zinc vacancies and introduced oxygen vacancies. This led to disappearance of the green luminescence band at 2.3(1) eV and appearance of a green emission at higher energy of 2.47(2) eV. Moreover, the color of the crystal was changed from colorless to dark red. In contrast, annealing of the as-grown crystal in Cd vapor did not remove zinc vacancies and did not cause any significant change of green luminescence nor change in coloration.

Origin of green luminescence in hydrothermally grown ZnO single crystals

International Nuclear Information System (INIS)

Čížek, J.; Hruška, P.; Melikhova, O.; Procházka, I.; Valenta, J.; Novotný, M.; Bulíř, J.

2015-01-01

Combining photoluminescence and positron annihilation studies of hydrothermally grown ZnO crystals with stoichiometry varied by controlled annealing enabled us to clarify the origin of green luminescence. It was found that green luminescence in ZnO has multiple origins and consists of a band at 2.3(1) eV due to recombination of electrons of the conduction band by zinc vacancy acceptors coupled with hydrogen and a band at 2.47(2) eV related to oxygen vacancies. The as-grown ZnO crystals contain zinc vacancies associated with hydrogen and exhibit a green luminescence at 2.3(1) eV. Annealing in Zn vapor removed zinc vacancies and introduced oxygen vacancies. This led to disappearance of the green luminescence band at 2.3(1) eV and appearance of a green emission at higher energy of 2.47(2) eV. Moreover, the color of the crystal was changed from colorless to dark red. In contrast, annealing of the as-grown crystal in Cd vapor did not remove zinc vacancies and did not cause any significant change of green luminescence nor change in coloration

Origin of green luminescence in hydrothermally grown ZnO single crystals

Science.gov (United States)

Čížek, J.; Valenta, J.; Hruška, P.; Melikhova, O.; Procházka, I.; Novotný, M.; Bulíř, J.

2015-06-01

Combining photoluminescence and positron annihilation studies of hydrothermally grown ZnO crystals with stoichiometry varied by controlled annealing enabled us to clarify the origin of green luminescence. It was found that green luminescence in ZnO has multiple origins and consists of a band at 2.3(1) eV due to recombination of electrons of the conduction band by zinc vacancy acceptors coupled with hydrogen and a band at 2.47(2) eV related to oxygen vacancies. The as-grown ZnO crystals contain zinc vacancies associated with hydrogen and exhibit a green luminescence at 2.3(1) eV. Annealing in Zn vapor removed zinc vacancies and introduced oxygen vacancies. This led to disappearance of the green luminescence band at 2.3(1) eV and appearance of a green emission at higher energy of 2.47(2) eV. Moreover, the color of the crystal was changed from colorless to dark red. In contrast, annealing of the as-grown crystal in Cd vapor did not remove zinc vacancies and did not cause any significant change of green luminescence nor change in coloration.

High-resolution light microscopy using luminescent nanoparticles.

Science.gov (United States)

Ohulchanskyy, Tymish Y; Roy, Indrajit; Yong, Ken-Tye; Pudavar, Haridas E; Prasad, Paras N

2010-01-01

This review presents recent progress in the development of the luminescent nanoparticles for confocal and multiphoton microscopy. Four classes of nanomaterials are discussed: (1) silica-based nanoparticles doped with fluorescent molecules, (2) gold nanoparticles, (3) semiconductor nanocrystals (quantum dots/rods), and (4) nanophosphors. Special considerations are given to recently developed imaging nanoprobes, such as (1) organically modified silica (ORMOSIL) nanoparticles doped with two-photon absorbing fluorophores, which exhibit aggregation-enhanced fluorescence (AEF), and (2) nanophosphors (ceramic nanoparticles containing luminescent lanthanoid ions). Advantages and disadvantages of every class of nanomaterials and their specific applications are briefly discussed.

Comparison of the gravimetric, phenol red, and 14C-PEG-3350 methods to determine water absorption in the rat single-pass intestinal perfusion model

OpenAIRE

Sutton, Steven C.; Rinaldi, M. T. S.; Vukovinsky, K. E.

2001-01-01

This study was undertaken to determine whether the gravimetric method provided an accurate measure of water flux correction and to compare the gravimetric method with methods that employ nonabsorbed markers (eg, phenol red and 14C-PEG-3350). Phenol red, 14C-PEG-3350, and 4-[2-[[2-(6-amino-3-pyridinyl)-2-hydroxyethyl]amino]ethoxy]-methyl ester, (R)-benzene acetic acid (Compound I) were co-perfused in situ through the jejunum of 9 anesthetized rats (single-pass intestinal perfusion [SPIP]). Wat...

Green and red luminescence in co-precipitation synthesized Pr:LuAG nanophosphor

Energy Technology Data Exchange (ETDEWEB)

Kumar, S. Arun; Kumar, K. Ashok; Gunaseelan, M.; Senthilselvan, J., E-mail: jsselvan@hotmail.com [Department of Nuclear Physics, University of Madras, Guindy Campus, Chennai–600 025, Tamil Nadu (India); Asokan, K. [Materials Science Group, Inter University Accelerator Centre, New Delhi-110067 (India)

2016-05-06

Pr:LuAG nanophosphor is an effective candidate in magnetic resonance imaging coupled positron emission tomography (MRI-PET) for medical imaging and scintillator applications. LuAG:Pr (0.05, 0.15 mol%) nanoscale ceramic powders were synthesized by co-precipitation method using urea as precipitant. Effect of antisite defect on structure and luminescence behavior was investigated. Pr:LuAG nanoceramic powders are found crystallized in cubic structure by high temperature calcination at 1400 °C and it shows antisite defect. HR-SEM analysis revealed spherically shaped Pr:LuAG nanoceramic particulate powders with ∼100 nm size. By the excitation at 450 nm, Pr:LuAG nanophosphor exhibit green to red luminescence in the wavelength range of 520 to 680 nm, which is originated from multiplet transition of Pr{sup 3+} ions.

Hydrothermal synthesis, characterization and luminescent ...

Indian Academy of Sciences (India)

Home; Journals; Bulletin of Materials Science; Volume 39; Issue 4. Hydrothermal synthesis, characterization and luminescent properties of lanthanide-doped NaLaF 4 nanoparticles. JIGMET LADOL HEENA KHAJURIA SONIKA KHAJURIA ... Keywords. Citric acid; X-ray diffraction; down-conversion emission; energy transfer.

Preparation, characterization and luminescence of nanocrystalline Y2O3:Ho

International Nuclear Information System (INIS)

Biljan, Tomislav; Gajovic, Andreja; Meic, Zlatko; Mestrovic, Ernest

2007-01-01

Nanocrystalline Y 2 O 3 :Ho was synthesized by solution combustion method with ethylene glycol as fuel. Material was characterized using powder X-ray diffraction and transmission electron microscopy (TEM). X-ray diffraction and TEM showed that the material is nanostructured. Luminescence properties were studied using Raman spectrometers with excitation in near infrared (NIR) and visible regions. The visible and NIR luminescence spectra of nanocrystalline Y 2 O 3 :Ho show some important differences from those of bulk material. The convenience of using Raman instruments for studying luminescence of lanthanide ions is demonstrated

Luminescent properties of LuPO4-Pr and LuPO4-Eu nanoparticles

International Nuclear Information System (INIS)

Vistovskyy, V.; Malyi, T.; Vas’kiv, A.; Chylii, M.; Mitina, N.; Zaichenko, A.; Gektin, A.; Voloshinovskii, A.

2016-01-01

Spectral-luminescence parameters of LuPO 4 -Eu and LuPO 4 -Pr nanoparticles of different sizes are studied upon excitation by the synchrotron radiation with photon energies 4–40 eV. Influence of the nanoparticle size on Eu 3+ and Pr 3+ impurity luminescence is analyzed for intracenter and recombination excitation. It is shown that the luminescence intensity of impurities in the case of recombination excitation significantly stronger decreases with decreasing of nanoparticle size compared to intracenter excitation. This feature is explained by the influence of thermalization length to nanoparticle size ratio on the recombination luminescence. Electron recombination luminescence inherent for LuPO 4 -Eu nanoparticles shows a weaker dependence on the nanoparticle size than the hole one in LuPO 4 -Pr nanoparticles. The difference between energy states of praseodymium impurity ions in nanoparticles of different sizes is revealed.

Luminescence Properties of Self-Aggregating TbIII-DOTA-Functionalized Calix[4]arenes

Directory of Open Access Journals (Sweden)

Florian Mayer

2018-01-01

Full Text Available Self-aggregating calix[4]arenes carrying four DOTA ligands on the upper rim for stable complexation of paramagnetic GdIII-ions have already been proposed as MRI probes. In this work, we investigate the luminescence properties of TbIII-DOTA-calix[4]arene-4OPr containing four propyl-groups and compare them with those of the analog substituted with a phthalimide chromophore (TbIII-DOTA-calix[4]arene-3OPr-OPhth. We show that, given its four aromatic rings, the calix[4]arene core acts as an effective sensitizer of Tb-centered luminescence. Substituents on the lower rim can modulate the aggregation behavior, which in turn determines the luminescence properties of the compounds. In solid state, the quantum yield of the phthalimide derivative is almost three times as high as that of the propyl-functionalized analog demonstrating a beneficial role of the chromophore on Tb-luminescence. In solution, however, the effect of the phthalimide group vanishes, which we attribute to the large distance between the chromophore and the lanthanide, situated on the opposite rims of the calix[4]arene. Both quantum yields and luminescence lifetimes show clear concentration dependence in solution, related to the strong impact of aggregation on the luminescence behavior. We also evidence the variability in the values of the critical micelle concentration depending on the experimental technique. Such luminescent calix[4]arene platforms accommodating stable lanthanide complexes can be considered valuable building blocks for the design of dual MR/optical imaging probes.

Circularly Polarized Luminescence from Inorganic Materials: Encapsulating Guest Lanthanide Oxides in Chiral Silica Hosts.

Science.gov (United States)

Sugimoto, Masumi; Liu, Xin-Ling; Tsunega, Seiji; Nakajima, Erika; Abe, Shunsuke; Nakashima, Takuya; Kawai, Tsuyoshi; Jin, Ren-Hua

2018-05-02

Recently, circularly polarized luminescence (CPL)-active systems have become a very hot and interesting subject in chirality- and optics-related areas. The CPL-active systems are usually available by two approaches: covalently combining a luminescent centre to chiral motif or associating the guest of luminescent probe to a chiral host. However, all the chiral components in CPL materials were organic, although the luminescent components were alternatively organics or inorganics. Herein, the first totally inorganic CPL-active system by "luminescent guest-chiral host" strategy is proposed. Luminescent sub-10 nm lanthanide oxides (Eu 2 O 3 or Tb 2 O 3 ) nanoparticles (guests) were encapsulated into chiral non-helical SiO 2 nanofibres (host) through calcination of chiral SiO 2 hybrid nanofibres, trapping Eu 3+ (or Tb 3+ ). These lanthanide oxides display circular dichroism (CD) optical activity in the ultraviolet wavelength and CPL signals around at 615 nm for Eu 3+ and 545 nm for Tb 3+ . This work has implications for inorganic-based CPL-active systems by incorporation of various luminescent guests within chiral inorganic hosts. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Construction of order mesoporous (Eu–La)/ZnO composite material and its luminescent characters

Energy Technology Data Exchange (ETDEWEB)

Bao, Na; Liu, Yu; Li, Zi-Wei [School of Chemistry & Environmental Engineering, Changchun University of Science and Technology, Changchun 130022 (China); Yu, Hui, E-mail: yh2001101@163.com [School of Chemistry & Environmental Engineering, Changchun University of Science and Technology, Changchun 130022 (China); Bai, Hao-tian [School of Chemistry & Environmental Engineering, Changchun University of Science and Technology, Changchun 130022 (China); Xia, Long, E-mail: xialong_aron@163.com [School of Materials Science and Engineering, Harbin Institute of Technology at Weihai, Weihai 264209 (China); Feng, Da-wei [Changchun University of Science and Technology Science Park, Changchun 130022 (China); Guangdong College of Business and Technology, Zhaoqing 526020 (China); Zhang, Hong-bo; Dong, Xiang-ting; Wang, Tian-yang; Han, Ji; Wu, Rong-yi; Zhang, Qi [School of Chemistry & Environmental Engineering, Changchun University of Science and Technology, Changchun 130022 (China)

2016-09-15

For the first time, the order mesoporous zinc oxide was synthesized by a soft template synthesis method. The Eu and La phosphate were introduced into the prepared mesoporous zinc oxide by the high temperature solid phase method, and got the mesoporous rare earth/zinc oxide composite materials. The luminescence characters of the materials were studied. The influences of La to Eu luminescent properties had been studied, and the optimum proportion of Eu and La was discussed. The influences of La and Eu to ZnO luminescence properties were also been studied. La phosphate had the large influence to Eu luminescent. ZnO had a strong emission peak at 469 nm, which overlapped with the {sup 7}F{sub 0}–{sup 5}D{sub 2} transition excitation peak of Eu at 465 nm. It indicated that the effective energy transfer happened between ZnO and Eu, which strongly enhanced the luminescence intensity of Eu. At the same time, the Eu and La phosphates could regulate the defect density of ZnO, which could regulate the luminescent intensity of ZnO, and realized the adjustment of luminescent color between green and red light.

A binder-free NiCo2O4 nanosheet/3D elastic N-doped hollow carbon nanotube sponge electrode with high volumetric and gravimetric capacitances for asymmetric supercapacitors.

Science.gov (United States)

Tong, Hao; Yue, Shihong; Lu, Liang; Jin, Fengqiao; Han, Qiwei; Zhang, Xiaogang; Liu, Jie

2017-11-09

To increase the volumetric and gravimetric capacitances of supercapacitors, a new class of electrode materials with high electrochemical activity and favorable structures is extremely desired. In this work, a hollow novel nitrogen-doped 3D elastic single-walled carbon nanotube sponge (NSCS) which is ultra lightweight with the lowest density of 0.8 mg cm -3 , and has a high open surface structure for electrolyte accessibility and excellent compressible properties as the electrode scaffold has been successfully fabricated by the pyrolysis method which could produce the carbon nanotube sponge easily on a large scale without high-cost and time-consuming processes. Moreover, a NiCo 2 O 4 nanosheet supported on the NSCS has been successfully fabricated. The highest volumetric and gravimetric capacitance of this electrode is 790 F cm -3 at 1.43 g cm -3 and 1618 F g -1 at 0.54 g cm -3 with excellent cycling stability. The density of NiCo 2 O 4 /NSCS electrode was adjusted by mechanical compression and the most favorable density of the film for both high volumetric and gravimetric capacitances obtained was 1.21 g cm -3 . The thick NiCo 2 O 4 /NSCS film of 72 μm has been fabricated at this favorable density, presenting both high volumetric and gravimetric capacitances of 597 F cm -3 and 1074 F g -1 at 1 A g -1 , respectively, indicating that the structure of the NSCS is extremely feasible for obtaining a thick film electrode with excellent volumetric and gravimetric capacitances. Furthermore, an asymmetric supercapacitor of NiCo 2 O 4 /NSCS//NGN/CNTs was fabricated, exhibiting a high gravimetric energy density of 47.65 W h kg -1 at 536 W kg -1 and a volumetric energy density of 33.44 W h L -1 at 376.16 W L -1 .

Device and method for luminescence enhancement by resonant energy transfer from an absorptive thin film

Science.gov (United States)

Akselrod, Gleb M.; Bawendi, Moungi G.; Bulovic, Vladimir; Tischler, Jonathan R.; Tisdale, William A.; Walker, Brian J.

2017-12-12

Disclosed are a device and a method for the design and fabrication of the device for enhancing the brightness of luminescent molecules, nanostructures, and thin films. The device includes a mirror, a dielectric medium or spacer, an absorptive layer, and a luminescent layer. The absorptive layer is a continuous thin film of a strongly absorbing organic or inorganic material. The luminescent layer may be a continuous luminescent thin film or an arrangement of isolated luminescent species, e.g., organic or metal-organic dye molecules, semiconductor quantum dots, or other semiconductor nanostructures, supported on top of the absorptive layer.

Spatially-resolved luminescence spectroscopy of CdSe quantum dots synthesized in ionic liquid crystal matrices

Energy Technology Data Exchange (ETDEWEB)

Magaryan, K.A., E-mail: xmagaros@gmail.com [Moscow State Pedagogical University, 29 Malaya Pirogovskaya Str., Moscow 119992 (Russian Federation); Mikhailov, M.A. [Moscow State Pedagogical University, 29 Malaya Pirogovskaya Str., Moscow 119992 (Russian Federation); Karimullin, K.R. [Moscow State Pedagogical University, 29 Malaya Pirogovskaya Str., Moscow 119992 (Russian Federation); Institute for Spectroscopy of RAS, 5 Fizicheskaya Str., Troitsk, Moscow 142190 (Russian Federation); E.K. Zavoyski Kazan Physical-Technical Institute of RAS, 10/7 Sibirski trakt Str., Kazan 420029 (Russian Federation); Knyazev, M.V.; Eremchev, I.Y. [Institute for Spectroscopy of RAS, 5 Fizicheskaya Str., Troitsk, Moscow 142190 (Russian Federation); Naumov, A.V. [Moscow State Pedagogical University, 29 Malaya Pirogovskaya Str., Moscow 119992 (Russian Federation); Institute for Spectroscopy of RAS, 5 Fizicheskaya Str., Troitsk, Moscow 142190 (Russian Federation); Vasilieva, I.A. [Moscow State Pedagogical University, 29 Malaya Pirogovskaya Str., Moscow 119992 (Russian Federation); Klimusheva, G.V. [Institute of Physics, NAS of Ukraine, 46 Prospect Nauki, Kiev 03028 (Ukraine)

2016-01-15

The paper is devoted to investigation of luminescence properties of new quantum dot (QD)-doped materials. We studied CdSe QDs (1.8 nm and 2.3 nm) grown inside of a liquid crystalline cadmium alcanoate matrix. Temperature dependence of parameters of fluorescence spectra obtained in a wide temperature range using epi-luminescence microscopy technique was analyzed. Spatially-resolved luminescence images were measured for the areas of the samples of 150×150 µm{sup 2}. Strong correlation between fluorescence spectra and sample structure was observed. - Highlights: • Glassy matrix with CdSe quantum dots inside fabricated in liquid crystalline mesophase. • Study of luminescence properties in a wide range of low temperatures. • Strong dependence of the luminescence spectra on spatial inhomogeneities. • Spatially-resolved luminescence imaging of quantum dots in liquid crystalline matrix.

Spatially-resolved luminescence spectroscopy of CdSe quantum dots synthesized in ionic liquid crystal matrices

International Nuclear Information System (INIS)

Magaryan, K.A.; Mikhailov, M.A.; Karimullin, K.R.; Knyazev, M.V.; Eremchev, I.Y.; Naumov, A.V.; Vasilieva, I.A.; Klimusheva, G.V.

2016-01-01

The paper is devoted to investigation of luminescence properties of new quantum dot (QD)-doped materials. We studied CdSe QDs (1.8 nm and 2.3 nm) grown inside of a liquid crystalline cadmium alcanoate matrix. Temperature dependence of parameters of fluorescence spectra obtained in a wide temperature range using epi-luminescence microscopy technique was analyzed. Spatially-resolved luminescence images were measured for the areas of the samples of 150×150 µm 2 . Strong correlation between fluorescence spectra and sample structure was observed. - Highlights: • Glassy matrix with CdSe quantum dots inside fabricated in liquid crystalline mesophase. • Study of luminescence properties in a wide range of low temperatures. • Strong dependence of the luminescence spectra on spatial inhomogeneities. • Spatially-resolved luminescence imaging of quantum dots in liquid crystalline matrix.

X-ray excited luminescence of polystyrene composites loaded with SrF{sub 2} nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Demkiv, T.M.; Halyatkin, O.O.; Vistovskyy, V.V. [Ivan Franko National University of Lviv, 8a Kyryla i Mefodiya St., 79005 Lviv (Ukraine); Hevyk, V.B. [Ivano-Frankivsk National Technical University of Oil and Gas, 15 Karpatska St., 76019 Ivano-Frankivsk (Ukraine); Yakibchuk, P.M. [Ivan Franko National University of Lviv, 8a Kyryla i Mefodiya St., 79005 Lviv (Ukraine); Gektin, A.V. [Institute for Scintillation Materials, NAS of Ukraine, 60 Lenina Ave, 61001 Kharkiv (Ukraine); Voloshinovskii, A.S. [Ivan Franko National University of Lviv, 8a Kyryla i Mefodiya St., 79005 Lviv (Ukraine)

2017-03-01

The polystyrene film nanocomposites of 0.3 mm thickness with embedded SrF{sub 2} nanoparticles up to 40 wt% have been synthesized. The luminescent and kinetic properties of the polystyrene composites with embedded SrF{sub 2} nanoparticles upon the pulse X-ray excitation have been investigated. The luminescence intensity of the pure polystyrene scintillator film significantly increases when it is loaded with the inorganic SrF{sub 2} nanoparticles. The film nanocomposites show fast (∼2.8 ns) and slow (∼700 ns) luminescence decay components typical for a luminescence of polystyrene activators (p-Terphenyl and POPOP) and SrF{sub 2} nanoparticles, respectively. It is revealed that the fast decay luminescence component of the polystyrene composites is caused by the excitation of polystyrene by the photoelectrons escaped from the nanoparticles due to photoeffect, and the slow component is caused by reabsorption of the self-trapped exciton luminescence of SrF{sub 2} nanoparticles by polystyrene.

Efficient and thermally stable red luminescence from nano-sized phosphor of Gd{sub 6}MoO{sub 12}:Eu{sup 3+}

Energy Technology Data Exchange (ETDEWEB)

Qin, Lin [Soochow University, College of Chemistry, Chemical Engineering and Materials Science (China); Wei, Donglei [Pukyong National University, Department of Physics and Interdisciplinary Program of Biomedical Engineering (Korea, Republic of); Huang, Yanlin [Soochow University, College of Chemistry, Chemical Engineering and Materials Science (China); Kim, Sun Il [Pukyong National University, Department of Physics and Interdisciplinary Program of Biomedical Engineering (Korea, Republic of); Yu, Young Moon [Pukyong National University, LED-Marin Convergence Technology R and BD Center (Korea, Republic of); Seo, Hyo Jin, E-mail: hjseo@pknu.ac.kr [Pukyong National University, Department of Physics and Interdisciplinary Program of Biomedical Engineering (Korea, Republic of)

2013-09-15

A novel red-emitting nano-phosphor of Eu{sup 3+}-doped Gd{sub 6}MoO{sub 12} was successfully synthesized by the Pechini method. The crystalline phase was confirmed by X-ray powder diffraction analysis. The morphology of the nano-phosphor was analyzed by scanning electron microscopy, indicating a good crystallization with particles smaller than 500 nm. The luminescence properties such as photoluminescence spectra and decay curves were investigated. The phosphors can be efficiently excited by near-ultraviolet (near-UV) light and exhibit a bright red luminescence around 613 nm ascribed to the forced electric dipole transition {sup 5}D{sub 0}{yields}{sup 7}F{sub 2} of Eu{sup 3+} ions. The thermal stabilities were investigated from the temperature-dependent luminescence decay curves (lifetimes) and spectra intensities. The luminescence properties in relation to applications in white light-emitting diodes (W-LEDs) such as the absolute luminescence quantum efficiency, excitation wavelength, and color coordinates were discussed. The Gd{sub 6}MoO{sub 12}:Eu{sup 3+} nano-phosphor is a promising red-emitting candidate for the fabrication of W-LEDs with near-UV chips.

Redox-induced reversible luminescence switching of cerium-doped upconversion nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Huang, Yanan [College of Sciences, Shanghai University, Shanghai 200444 (China); International Laboratory for Adaptive Bio-nanotechnology, Suzhou Institute of Nano-tech and Nano-bionics (SINANO), Chinese Academy of Science, Suzhou 215123 (China); Xiao, Qingbo, E-mail: qbxiao2011@sinano.ac.cn [International Laboratory for Adaptive Bio-nanotechnology, Suzhou Institute of Nano-tech and Nano-bionics (SINANO), Chinese Academy of Science, Suzhou 215123 (China); Wang, Jian [College of Sciences, Shanghai University, Shanghai 200444 (China); International Laboratory for Adaptive Bio-nanotechnology, Suzhou Institute of Nano-tech and Nano-bionics (SINANO), Chinese Academy of Science, Suzhou 215123 (China); Xi, Yonglan [Laboratory for Agricultural Wastes Treatment and Recycling Institute of Agricultural Resources and Environment, Jiangsu Academy of Agricultural Science, Nanjing 210014 (China); Li, Fujin [International Laboratory for Adaptive Bio-nanotechnology, Suzhou Institute of Nano-tech and Nano-bionics (SINANO), Chinese Academy of Science, Suzhou 215123 (China); Feng, Yamin [College of Sciences, Shanghai University, Shanghai 200444 (China); International Laboratory for Adaptive Bio-nanotechnology, Suzhou Institute of Nano-tech and Nano-bionics (SINANO), Chinese Academy of Science, Suzhou 215123 (China); Shi, Liyi [College of Sciences, Shanghai University, Shanghai 200444 (China); Lin, Hongzhen, E-mail: hzlin2010@sinano.ac.cn [International Laboratory for Adaptive Bio-nanotechnology, Suzhou Institute of Nano-tech and Nano-bionics (SINANO), Chinese Academy of Science, Suzhou 215123 (China)

2016-05-15

Smart upconversion nanophosphors (UCNPs) that can be reversibly switched between two or more luminescent states by certain external stimuli have attracted considerable attention due to their great potential in biological applications. Here we report for the first time a type of redox-switchable UCNPs by codoping NaGdF{sub 4}:Yb/Er nanorods with the redox-active Ce{sup 3+}/Ce{sup 4+} ion pairs. A reversible switching of their UC luminescence intensity was observed upon the variation of the surrounding redox environments. We show solid proof that the luminescence switching is caused by the tailoring of the NaGdF{sub 4} host crystal structure in response to changing redox state of the codoped cerium ions. A proof-of-concept example is further demonstrated by using these UCNPs for probing the dynamical variation of redox environments in biological tissues. - Highlights: • Synthesis of upconversion nanoparticles doped with Ce{sup 3+}/Ce{sup 4+} ions. • The precise and reversible modification of crystal structure by redox reactions. • Tuning the upconversion luminescence by tailoring the crystal structure.

Mechanism of band-edge luminescence in cuprous iodide single crystals

International Nuclear Information System (INIS)

Gao, Pan; Gu, Mu; Liu, Xi; Liu, Bo; Zheng, Yan-Qing; Shi, Er-Wei; Shi, Jun-Yan; Zhang, Guo-bin

2014-01-01

Highlights: • The luminescence properties of CuI crystals are influenced by the quality of the as-grown crystals. • The emission peaks of free-exciton and bound-exciton are observed in the CuI single crystals. • The ultrafast component luminescence is warranted to the donor-acceptor pair recombination. • The exciton absorption and electron excitation multiplication processes were observed in CuI. - Abstract: The photoluminescence spectra of CuI crystals using synchrotron radiation as an excitation light source were obtained at 60 K. The emission peaks at 405, 415, 420 and 443 nm were observed. The possible origins of these peaks were discussed by the temperature dependence of luminescence spectra for CuI material. Meanwhile, the photoluminescence spectra of CuI powder with different excitation intensity were measured and the ultrafast luminescence component of CuI crystals was warranted to be attributed to the recombination of donor acceptor pair. Furthermore, the excitation process was studied by measuring the photoluminescence excitation spectra of CuI crystals and powder

Direct determination of graphene quantum dots based on terbium-sensitized luminescence

Science.gov (United States)

Llorent-Martínez, Eulogio J.; Molina-García, Lucía; Durán, Gema M.; Ruiz-Medina, Antonio; Ríos, Ángel

2018-06-01

Graphene quantum dots (GQD) were determined in water samples using terbium-sensitized luminescence (TSL). Terbium ions complex with GQD due to the carboxylic groups that are usually present in these nanomaterials, increasing the luminescence signal of terbium. In Tb(III)-GQD complexes, GQD absorb energy at their characteristic excitation wavelength and transfer it to terbium ion, which emits at its particular emission wavelength. The analytical signal, measured at λexc = 257 nm and λem = 545 nm, increases proportionally to GQD concentration between 50 and 500 μg L-1. Under optimum conditions, the proposed method presents a detection limit of 15 μg L-1 and is selective to GQD in the presence of other nanomaterials of similar size. As GQD are highly water-soluble, they are potential contaminants in environmental or drinking waters water samples, and hence the method was applied to the analysis of different drinking waters which were the target samples for the application of the developed method.

Room-temperature luminescence decay of colloidal semiconductor quantum dots: Nonexponentiality revisited

Energy Technology Data Exchange (ETDEWEB)

Bodunov, Evgeny N. [Department of Physics, Petersburg State Transport University, St. Petersburg (Russian Federation); Danilov, Vladimir V. [Department of Physics, Petersburg State Transport University, St. Petersburg (Russian Federation); Vavilov State Optical Institute, St. Petersburg (Russian Federation); Panfutova, Anastasia S. [Vavilov State Optical Institute, St. Petersburg (Russian Federation); Simoes Gamboa, A.L. [Center of Information Optical Technologies, ITMO University, St. Petersburg (Russian Federation)

2016-04-15

While time-resolved luminescence spectroscopy is commonly used as a quantitative tool for the analysis of the dynamics of photoexcitation in colloidal semiconductor quantum dots, the interpretation of the virtually ubiquitous nonexponential decay profiles is frequently ambiguous, because the assumption of multiple discrete exponential components with distinct lifetimes for resolving the decays is often arbitrary. Here, an interpretation of the room-temperature luminescence decay of CdSe/ZnS semiconductor quantum dots in colloidal solutions is presented based on the Kohlrausch relaxation function. It is proposed that the decay can be understood by using the concept of Foerster resonance energy transfer (FRET) assuming that the role of acceptors of photoexcitation energy is played by high-frequency anharmonic molecular vibrations in the environment of the quantum dots. The term EVFRET (Electronic - Vibrational Foerster Resonance Energy Transfer) is introduced in order to unequivocally refer to this energy transfer process. (copyright 2016 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Raman scattering and luminescence of high-Tc superconducting oxides

International Nuclear Information System (INIS)

Eremenko, V.V.; Gnezdilov, V.P.; Fomin, V.I.; Fugol', I.Ya.; Samovarov, V.N.

1989-01-01

Raman and luminescence spectra of high-T c superconducting oxides are summarized, mainly YBa 2 Cu 3 O 7-σ and partly La 2-x Ba x CuO 4-σ . In raman spectra we succeeded to distinguish electron scattering to define the energy gap Δ in the superconducting state. The luminescence spectra are due to the emission of oxygen and interaction with conduction electrons. 70 refs.; 13 figs

X-Ray Absorption Near-Edge Structure (XANES) of Calcium L3,2 Edges of Various Calcium Compounds and X-Ray Excited Optical Luminescence (XEOL) Studies of Luminescent Calcium Compounds

International Nuclear Information System (INIS)

Ko, J. Y. Peter; Zhou Xingtai; Sham, T.-K.; Heigl, Franziskus; Regier, Tom; Blyth, Robert

2007-01-01

X-ray absorption at calcium L3,2 edges of various calcium compounds were measured using a high resolution Spherical Grating Monochromator (SGM) at the Canadian Light Source (CLS). We observe that each compound has its unique fine structure of L3,2 edges. This uniqueness is due to differences in local structure of compounds. We also performed (X-ray Excited Optical Luminescence) XEOL of selected luminescent calcium compounds to investigate their optical properties. XEOL is a photon-in-photon-out technique in which the optical luminescence that is excited by tunable x-rays from a synchrotron light source is monitored. Depending on excitation energy of the x-ray, relative intensities of luminescence peaks vary. Recent findings of the results will be presented here

Luminescence and scintillation properties of LuPO4-Ce nanoparticles

International Nuclear Information System (INIS)

Vistovskyy, V.; Malyy, T.; Pushak, A.; Vas’kiv, A.; Shapoval, A.; Mitina, N.; Gektin, A.; Zaichenko, A.; Voloshinovskii, A.

2014-01-01

Study of the spectral-luminescence parameters of LuPO 4 -Ce nanoparticles upon the excitation by X-ray quanta and synchrotron radiation with photon energies of 4–25 eV was performed. Nanoparticles with mean size about a=35 nm and nanoparticles with size less than 12 nm reveal the different structures of cerium centers. Luminescence efficiency of LuPO 4 -Ce nanoparticles of a 4 -Ce nanoparticles studied using synchrotron and X-ray excitation. • Different structure of Ce 3+ -centers has been revealed for LuPO 4 -Ce nanoparticles. • Luminescence of LuPO 4 -Ce with size less than 12 nm is strongly quenched upon the X-ray excitation

STUDIES ON BIOLUMINESCENCE : XVII. FLUORESCENCE AND INHIBITION OF LUMINESCENCE IN CTENOPHORES BY ULTRA-VIOLET LIGHT.

Science.gov (United States)

Harvey, E N

1925-01-20

1. Small dumps of the luminous cells of Mnemiopsis cannot readily be stimulated mechanically but will luminesce on treatment with saponin solution. Larger groups of luminous cells (such as are connected with two paddle plates) luminesce on mechanical stimulation. This suggests that mechanical stimulation to luminesce occurs chiefly through a nerve mechanism which has been broken up in the small dumps of luminous tissue. 2. The smallest bits of luminous tissue, even cells freed from the animal by agitation, that will pass through filter paper, lose their power to luminesce in daylight and regain it (at least partially) in the dark. 3. Luminescence of the whole animal and of individual cells is suppressed by near ultra-violet light (without visible light). 4. Inhibition in ultra-violet light is not due to stimulation (by the ultra-violet light) of the animal to luminesce, thereby using up the store of photogenic material. 5. Animals stimulated mechanically several times and placed in ultra-violet light show a luminescence along the meridians in the same positions as the luminescence that appears on stimulation. This luminescence in the ultra-violet or "tonic luminescence," is not obtained with light adapted ctenophores and is interpreted to be a fluorescence of the product of oxidation of the photogenic material. 6. Marked fluorescence of the luminous organ of the glowworm (Photuris) and of the luminous slime of Chatopterus may be observed in ultra-violet but no marked fluorescence of the luminous substances of Cypridina is apparent. 7. Evidence is accumulating to show a close relation between fluorescent and chemiluminescent substances in animals, similar to that described for unsaturated silicon compounds and the Grignard reagents.

Delayed luminescence in a multiparameter approach to evaluation and reduction of radiobiological risks

Science.gov (United States)

Grasso, Rosaria; Cammarata, Francesco Paolo; Minafra, Luigi; Marchese, Valentina; Russo, Giorgio; Manti, Lorenzo; Musumeci, Francesco; Scordino, Agata

2017-07-01

In the framework of the research project ETHICS "Pre-clinical experimental and theoretical studies to improve treatment and protection by charged particles" funded by the National Nuclear Physics Institute, Italy, we studied the phenomenon called delayed luminescence emitted by non-tumorigenic breast epithelial MCF10A cell line after proton irradiation at different doses (0.5, 2, 6, 9 Gy). The aim is to found possible correlations between delayed luminescence and in vitro damaging induced by ion irradiation. The first results of this research show that the delayed luminescence kinetics is proton dose dependent. An interesting correlation between delayed luminescence and clonogenic potential was observed.

Afterglow luminescence in sol-gel/Pechini grown oxide materials: persistence or phosphorescence process? (Conference Presentation)

Science.gov (United States)

Sontakke, Atul; Ferrier, Alban; Viana, Bruno

2017-03-01

Persistent luminescence and phosphorescence, both yields afterglow luminescence, but are completely different mechanisms. Persistent luminescence involves a slow thermal release of trapped electrons stored in defect states, whereas the phosphorescence is caused due to triplet to singlet transition [1,2]. Many persistent luminescence phosphors are based on oxide inorganic hosts, and exhibit long afterglow luminescence after ceasing the excitation. We observed intense and long afterglow luminescence in sol-gel/pechini grown inorganic oxides, and as a first interpretation thought to be due to persistence mechanism. However, some of these materials do not exhibit defect trap centers, and a detailed investigation suggested it is due to phosphorescence, but not the persistence. Phosphorescence is not common in inorganic solids, and that too at room temperature, and therefore usually misinterpreted as persistence luminescence [3]. Here we present a detailed methodology to distinguish phosphorescence from persistence luminescence in inorganic solids, and the process to harvest highly efficient long phosphorescence afterglow at room temperature. 1. Jian Xu, Setsuhisa Tanabe, Atul D. Sontakke, Jumpei Ueda, Appl. Phys. Lett. 107, 081903 (2015) 2. Sebastian Reineke, Marc A. Baldo, Scientific Reports, 4, 3797 (2014) 3. Pengchong Xue, Panpan Wang, Peng Chen, Boqi Yao, Peng Gong, Jiabao Sun, Zhenqi Zhang, Ran Lu, Chem. Sci. (2016) DOI: 10.1039/C5SC03739E

Plasmon-enhanced luminescence of Sm complex using silver nanoparticles in Polyvinyl Alcohol

Energy Technology Data Exchange (ETDEWEB)

Kaur, Gagandeep; Verma, R.K.; Rai, D.K. [Laser and Spectroscopy Laboratory, Department of Physics, Banaras Hindu University, India 221005 (India); Rai, S.B., E-mail: sbrai49@yahoo.co.in [Laser and Spectroscopy Laboratory, Department of Physics, Banaras Hindu University, India 221005 (India)

2012-07-15

Silver (Ag) nanoparticles (NPs) were prepared by laser ablation in water with an aim to enhance the luminescence of rare earth coordinated complex in polymer host. A fixed concentration of the complex containing Samarium (Sm), Salicylic acid (Sal) and 1, 10-phenanthroline (Phen) were combined with different concentrations of silver NPs in PolyVinyl Alcohol at room temperature. Absorption spectrum and XRD patterns of the sample show that the Sm(Sal){sub 3}Phen complex is accompanied by Ag NPs. The luminescence from the complex was recorded in the presence and absence of Ag NPs using two different excitation wavelengths viz. 400 and 355 nm. Of these, 400 nm radiation falls in the surface plasmon resonance of Ag NPs. It was found that the Ag NPs led to a significant enhancement in luminescence of the complex. Surprisingly, a high concentration of Ag NPs tends to quench the luminescence. - Highlights: Black-Right-Pointing-Pointer Sm complex with Ag nanoparticles in PVA was prepared at room temperature. Black-Right-Pointing-Pointer UV-vis absorption and XRD confirms the presence of Sm complex and Ag NPs. Black-Right-Pointing-Pointer Enhancement in luminescence of complex was observed with Ag NPs. Black-Right-Pointing-Pointer Coupling between radiative transitions of Sm and SPR of NPs enhances the emission. Black-Right-Pointing-Pointer The higher concentration of Ag NPs quenches the luminescence of the complex.

Features of the core-valence luminescence and electron energy band structure of A1-xCsxCaCl3 (A = K,Rb) crystals

International Nuclear Information System (INIS)

Chornodolskyy, Ya; Stryganyuk, G; Syrotyuk, S; Voloshinovskii, A; Rodnyi, P

2007-01-01

From luminescence spectroscopy of CsCaCl 3 , Rb 1-x Cs x CaCl 3 and K 1-x Cs x CaCl 3 crystals, we have found evidence for intrinsic and impurity core-valence luminescence due to the radiative recombination of valence electrons with the holes of intrinsic or impurity 5p Cs + core states. The structural similarity of core-valence luminescence spectra has been revealed for the A 1-x Cs x CaCl 3 (A = K,Rb) crystals investigated. The electron energy structure of the CsCaCl 3 crystal has been calculated using the pseudopotential approach taking into account the gradient corrections for the exchange-correlation energy. The calculated density of the electronic states of CsCaCl 3 has been compared with corresponding parameters obtained from the analysis of core-valence luminescence spectra

Luminescent Metal Nanoclusters for Potential Chemosensor Applications

Directory of Open Access Journals (Sweden)

Muthaiah Shellaiah

2017-12-01

Full Text Available Studies of metal nanocluster (M-NCs-based sensors for specific analyte detection have achieved significant progress in recent decades. Ultra-small-size (<2 nm M-NCs consist of several to a few hundred metal atoms and exhibit extraordinary physical and chemical properties. Similar to organic molecules, M-NCs display absorption and emission properties via electronic transitions between energy levels upon interaction with light. As such, researchers tend to apply M-NCs in diverse fields, such as in chemosensors, biological imaging, catalysis, and environmental and electronic devices. Chemo- and bio-sensory uses have been extensively explored with luminescent NCs of Au, Ag, Cu, and Pt as potential sensory materials. Luminescent bi-metallic NCs, such as Au-Ag, Au-Cu, Au-Pd, and Au-Pt have also been used as probes in chemosensory investigations. Both metallic and bi-metallic NCs have been utilized to detect various analytes, such as metal ions, anions, biomolecules, proteins, acidity or alkalinity of a solution (pH, and nucleic acids, at diverse detection ranges and limits. In this review, we have summarized the chemosensory applications of luminescent M-NCs and bi-metallic NCs.

Sequence and function of LuxO, a negative regulator of luminescence in Vibrio harveyi.

Science.gov (United States)

Bassler, B L; Wright, M; Silverman, M R

1994-05-01

Density-dependent expression of luminescence in Vibrio harveyi is regulated by the concentration of extracellular signal molecules (autoinducers) in the culture medium. A recombinant clone that restored function to one class of spontaneous dim mutants was found to encode a function required for the density-dependent response. Transposon Tn5 insertions in the recombinant clone were isolated, and the mutations were transferred to the genome of V. harveyi for examination of mutant phenotypes. Expression of luminescence in V. harveyi strains with transposon insertions in one locus, luxO, was independent of the density of the culture and was similar in intensity to the maximal level observed in wild-type bacteria. Sequence analysis of luxO revealed one open reading frame that encoded a protein, LuxO, similar in amino acid sequence to the response regulator domain of the family of two-component, signal transduction proteins. The constitutive phenotype of LuxO- mutants indicates that LuxO acts negatively to control expression of luminescence, and relief of repression by LuxO in the wild type could result from interactions with other components in the Lux signalling system.

Luminescence from hydrodynamic cavitation. Method and preliminary analysis

International Nuclear Information System (INIS)

Leighton, T.; Farhat, M.; Field, J.

2001-01-01

This report describes a photon-counting study of the cavitation luminescence produced by flow over a hydrofoil. The object was to obtain quantitative data on the number of photons emitted for various flow conditions and to study the link between the light output and the potential for cavitation damage. The flow experiments were performed in a cavitation tunnel capable of achieving flow velocities of up to ca. 50 m s -1 in the test sections. The experimental hydrofoil was a NACA 009 blade. Parameters varied were the flow velocity, the incident angle of the hydrofoil and the cavitation index. The results show that significant photon counts are recorded when leading edge cavitation takes place and U-shaped vortices (cavities) shed from the main cavity. The photon count increases dramatically as the flow velocity increases or the cavitation index is reduced. Departure from a Poisson distribution in the arrival times of photons at the detector may be related to the way vortices shed from the main cavity. Finally, there is a clear correlation between light output and the conditions which could cause cavitation damage. (author)

Luminescence from hydrodynamic cavitation. Method and preliminary analysis

Energy Technology Data Exchange (ETDEWEB)

Leighton, T.; Farhat, M.; Field, J. [and others

2001-06-01

This report describes a photon-counting study of the cavitation luminescence produced by flow over a hydrofoil. The object was to obtain quantitative data on the number of photons emitted for various flow conditions and to study the link between the light output and the potential for cavitation damage. The flow experiments were performed in a cavitation tunnel capable of achieving flow velocities of up to ca. 50 m s{sup -1} in the test sections. The experimental hydrofoil was a NACA 009 blade. Parameters varied were the flow velocity, the incident angle of the hydrofoil and the cavitation index. The results show that significant photon counts are recorded when leading edge cavitation takes place and U-shaped vortices (cavities) shed from the main cavity. The photon count increases dramatically as the flow velocity increases or the cavitation index is reduced. Departure from a Poisson distribution in the arrival times of photons at the detector may be related to the way vortices shed from the main cavity. Finally, there is a clear correlation between light output and the conditions which could cause cavitation damage. (author)

Direct and indirect dating of gypsum occurrences in deserts using luminescence methods

International Nuclear Information System (INIS)

Nagar, Y.C.; Juyal, N.; Singhyi, A.K.; Kocurek, G.; Wadhawan, S.K.

2005-01-01

In the present study we have made an attempt to directly date gypsum or provide indirect age estimate for gypsum formation through dating the associated sediments (quartz) using the luminescence dating technique. In the direct dating of gypsum, we explored the Optically Stimulated Luminescence (OSL) and Thermally Stimulated Luminescence (TL) behaviour of gypsum. The associated sediments (indirect dating) were dated using the traces of quartz extract from gypsum (concentration 0.1% ) and the underlying and overlying quartz sand in playa

Assessment of terbium (III) as a luminescent probe for the detection of tuberculosis biomarkers

International Nuclear Information System (INIS)

Bamogo, W.; Mugherli, L.; Banyasz, A.; Novelli-Rousseau, A.; Mallard, F.; Tran-Thi, T.-H.

2015-01-01

A detection method for nicotinic acid, a specific metabolite marker of Mycobacterium tuberculosis present in cultures and patients' breath, is studied in complex solutions containing other metabolites and in biological media such as urine, saliva and breath condensate. The method is based on the analysis of the luminescence increase of Tb 3+ complexes in the presence of nicotinic acid due to the energy transfer from the excited ligand to the lanthanide ion. It is shown that other potential markers found in M. tuberculosis culture supernatant, such as methyl phenylacetate, p-methyl anisate, methyl nicotinate and 2-methoxy biphenyl, can interfere with nicotinic acid via a competitive absorption of the excitation photons. A new strategy to circumvent these interferences is proposed with an upstream trapping of volatile markers preceding the detection of nicotinic acid in the liquid phase via the luminescence of Tb 3+ complexes. The cost of the method is evaluated and compared with the Xpert MTB/RIF test endorsed by the World Health Organization. - Highlights: • Nicotinic acid, a specific marker of M. tuberculosis, can be detected via luminescence. • The detection limit with a commercial phosphorimeter is 0.4 µmol·L -1 . • Other metabolites of M. tuberculosis can interfere via absorbed excitation light. • The interference can be removed via trapping of the most volatile metabolites. • A breath analysis procedure's cost is compared with the Xpert TBM/RIF test.

Assessment of terbium (III) as a luminescent probe for the detection of tuberculosis biomarkers

Energy Technology Data Exchange (ETDEWEB)

Bamogo, W. [CNRS, IRAMIS, UMR 3685 NIMBE/LEDNA, F-91191 Gif-sur-Yvette (France); Mugherli, L. [CEA, IRAMIS, UMR 3685 NIMBE/LEDNA, F-91191 Gif-sur-Yvette (France); Banyasz, A. [CNRS, IRAMIS, LIDyL/Laboratoire Francis Perrin, URA 2453, F-91191 Gif-sur-Yvette (France); Novelli-Rousseau, A.; Mallard, F. [BioMérieux SA, F-38000 Grenoble (France); Tran-Thi, T.-H., E-mail: thu-hoa.tran-thi@cea.fr [CNRS, IRAMIS, UMR 3685 NIMBE/LEDNA, F-91191 Gif-sur-Yvette (France)

2015-10-08

A detection method for nicotinic acid, a specific metabolite marker of Mycobacterium tuberculosis present in cultures and patients' breath, is studied in complex solutions containing other metabolites and in biological media such as urine, saliva and breath condensate. The method is based on the analysis of the luminescence increase of Tb{sup 3+} complexes in the presence of nicotinic acid due to the energy transfer from the excited ligand to the lanthanide ion. It is shown that other potential markers found in M. tuberculosis culture supernatant, such as methyl phenylacetate, p-methyl anisate, methyl nicotinate and 2-methoxy biphenyl, can interfere with nicotinic acid via a competitive absorption of the excitation photons. A new strategy to circumvent these interferences is proposed with an upstream trapping of volatile markers preceding the detection of nicotinic acid in the liquid phase via the luminescence of Tb{sup 3+} complexes. The cost of the method is evaluated and compared with the Xpert MTB/RIF test endorsed by the World Health Organization. - Highlights: • Nicotinic acid, a specific marker of M. tuberculosis, can be detected via luminescence. • The detection limit with a commercial phosphorimeter is 0.4 µmol·L{sup -1}. • Other metabolites of M. tuberculosis can interfere via absorbed excitation light. • The interference can be removed via trapping of the most volatile metabolites. • A breath analysis procedure's cost is compared with the Xpert TBM/RIF test.

Growth-morphology-luminescence correlation in ZnO-containing nanostructures synthesized in different media

Energy Technology Data Exchange (ETDEWEB)

Japic, Dajana [Laboratory for the Spectroscopy of the Materials, National Institute of Chemistry, Hajdrihova 19, 1001 Ljubljana (Slovenia); Antonio Paramo, J. [Department of Physics and Astronomy Texas Christian University, TCU Box 298840, Fort Worth, TX 76129 (United States); Marinsek, Marjan [Faculty of Chemistry and Chemical Technology, University of Ljubljana, Askerceva cesta 5, 1000 Ljubljana (Slovenia); Strzhemechny, Yuri M., E-mail: Y.Strzhemechny@tcu.edu [Department of Physics and Astronomy Texas Christian University, TCU Box 298840, Fort Worth, TX 76129 (United States); Crnjak Orel, Zorica, E-mail: zorica.crnjak.orel@ki.si [Laboratory for the Spectroscopy of the Materials, National Institute of Chemistry, Hajdrihova 19, 1001 Ljubljana (Slovenia); Centre of Excellence Polimat, Tehnoloski Park 24, 1000 Ljubljana (Slovenia)

2012-06-15

Zinc hydroxide particles were prepared by a two-step process employing zinc nitrate hexahydrate, urea, ethylene glycol, water and p-toluene-sulfonic acid monohydrate (p-TSA). We used different concentrations of the reactants as well as different volume ratios of the solvents. ZnO particles were obtained by thermal treatment of the reaction products at two different temperatures: 350 Degree-Sign C and 500 Degree-Sign C. The samples were characterized by scanning field emission electron microscopy (SEM), X-ray diffraction (XRD) spectroscopy, BET analysis, thermogravimetry (TG) analysis and photoluminescence (PL) spectroscopy. It was found that after the thermal treatment particles become smaller, with the p-TSA concentration strongly affecting the morphology of the particles. Luminescence properties of the samples probed by PL at 8 K and room temperature exhibited a remarkable correlation with specimens Prime nanomorphology. Luminescent features at {approx}2.0-2.2 eV, {approx}2.4-2.5 eV, {approx}2.65 eV, {approx}2.9 eV, {approx}3.0-3.1 eV and {approx}3.3 eV were observed in most specimens, although their relative intensity and temperature dependence were specific to an individual group of samples vis-a-vis their growth history and morphology. - Highlights: Black-Right-Pointing-Pointer ZnO-containing nanostructures grown by precipitation were investigated. Black-Right-Pointing-Pointer Samples' morphology can be carefully tailored via growth control parameters. Black-Right-Pointing-Pointer Strong dependence of optoelectronic properties on specimens' morphology was observed. Black-Right-Pointing-Pointer Efficient control of composition, morphology and luminescence via synthesis parameters.

Growth-morphology-luminescence correlation in ZnO-containing nanostructures synthesized in different media

International Nuclear Information System (INIS)

Japic, Dajana; Antonio Paramo, J.; Marinsek, Marjan; Strzhemechny, Yuri M.; Crnjak Orel, Zorica

2012-01-01

Zinc hydroxide particles were prepared by a two-step process employing zinc nitrate hexahydrate, urea, ethylene glycol, water and p-toluene-sulfonic acid monohydrate (p-TSA). We used different concentrations of the reactants as well as different volume ratios of the solvents. ZnO particles were obtained by thermal treatment of the reaction products at two different temperatures: 350 °C and 500 °C. The samples were characterized by scanning field emission electron microscopy (SEM), X-ray diffraction (XRD) spectroscopy, BET analysis, thermogravimetry (TG) analysis and photoluminescence (PL) spectroscopy. It was found that after the thermal treatment particles become smaller, with the p-TSA concentration strongly affecting the morphology of the particles. Luminescence properties of the samples probed by PL at 8 K and room temperature exhibited a remarkable correlation with specimens′ nanomorphology. Luminescent features at ∼2.0–2.2 eV, ∼2.4–2.5 eV, ∼2.65 eV, ∼2.9 eV, ∼3.0–3.1 eV and ∼3.3 eV were observed in most specimens, although their relative intensity and temperature dependence were specific to an individual group of samples vis-à-vis their growth history and morphology. - Highlights: ► ZnO-containing nanostructures grown by precipitation were investigated. ► Samples' morphology can be carefully tailored via growth control parameters. ► Strong dependence of optoelectronic properties on specimens' morphology was observed. ► Efficient control of composition, morphology and luminescence via synthesis parameters.

Anomalous enhancement of nanodiamond luminescence upon heating

Science.gov (United States)

Khomich, A. A.; Kudryavtsev, O. S.; Dolenko, T. A.; Shiryaev, A. A.; Fisenko, A. V.; Konov, V. I.; Vlasov, I. I.

2017-02-01

Characteristic photoluminescence (PL) of nanodiamonds (ND) of different origin (detonation, HPHT, extracted from meteorite) was studied in situ at high temperatures in the range 20-450 °C. Luminescence was excited using 473 nm laser and recorded in the range 500-800 nm. In contrast to decrease of point defect PL in bulk diamond with temperature, we found that the ND luminescence related to ND surface defects increases almost an order of magnitude upon heating to 200-250 °C. The observed effect reveals that water adsorbed on ND surfaces efficiently quenches PL; water desorption on heating leads to dramatic increase of the radiative de-excitation.

Luminescent Lanthanide Reporters for High-Sensitivity Novel Bioassays

Energy Technology Data Exchange (ETDEWEB)

Anstey, Mitchell R. [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Fruetel, Julia A. [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Foster, Michael E. [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Hayden, Carl C. [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Buckley, Heather L. [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Arnold, John [Sandia National Lab. (SNL-CA), Livermore, CA (United States)

2013-09-01

Biological imaging and assay technologies rely on fluorescent organic dyes as reporters for a number of interesting targets and processes. However, limitations of organic dyes such as small Stokes shifts, spectral overlap of emission signals with native biological fluorescence background, and photobleaching have all inhibited the development of highly sensitive assays. To overcome the limitations of organic dyes for bioassays, we propose to develop lanthanide-based luminescent dyes and demonstrate them for molecular reporting applications. This relatively new family of dyes was selected for their attractive spectral and chemical properties. Luminescence is imparted by the lanthanide atom and allows for relatively simple chemical structures that can be tailored to the application. The photophysical properties offer unique features such as narrow and non-overlapping emission bands, long luminescent lifetimes, and long wavelength emission, which enable significant sensitivity improvements over organic dyes through spectral and temporal gating of the luminescent signal.Growth in this field has been hindered due to the necessary advanced synthetic chemistry techniques and access to experts in biological assay development. Our strategy for the development of a new lanthanide-based fluorescent reporter system is based on chelation of the lanthanide metal center using absorbing chromophores. Our first strategy involves "Click" chemistry to develop 3-fold symmetric chelators and the other involves use of a new class of tetrapyrrole ligands called corroles. This two-pronged approach is geared towards the optimization of chromophores to enhance light output.

Luminescent properties of Al2O3: Tb powders

International Nuclear Information System (INIS)

Esparza G, A.E.; Garcia, M.; Falcony, C.; Azorin N, J.

2000-01-01

In this work the photo luminescent and cathode luminescent characteristics of aluminium oxide (Al 2 O 3 ) powders impurified with terbium (Tb) were studied for their use in dosimetry. The optical, structural, morphological characteristics of the powders as function of variation in the impurity concentration and the annealing temperature will be presented. As regards the optical properties of powders (photoluminescence and cathode luminescence) it was observed a characteristic emission associated with radiative transitions between electron energy levels of terbium, the spectra associated with this emission consists of several peaks associated with such transitions. In the structural and morphological characterization (X-ray diffraction and scanning electron microscopy) it was appreciated that in accordance the annealing temperature of powders is augmented it is evident the apparition of certain crystalline phases. The results show that this is a promissory material for radiation dosimetry. (Author)

Fiber-coupled Luminescence Dosimetry in Therapeutic and Diagnostic Radiology

DEFF Research Database (Denmark)

Andersen, Claus Erik

2011-01-01

. Some crystalline phosphors, such as carbon-doped aluminium oxide (Al2O3:C) have the ability to store charge produced in the crystal during irradiation. The stored charge may later be released by fiber-guided laser light under emission of so-called optically stimulated luminescence (OSL). The OSL signal......Fiber-coupled luminescence dosimetry is an emerging technology with several potentially attractive features of relevance for uses in therapeutic and diagnostic radiology: direct water equivalence (i.e. no significant perturbation of the radiation field in a water phantom or a patient), sub......-mm detector size, high dynamic range (below a mGy to several Gy), microsecond time resolution, and absence of electrical wires or other electronics in the dosimeter probe head. Fiber-coupled luminescence dosimetry systems typically consist of one or more small samples of phosphor, e.g. a mg of plastic...

Performance of a novel multiple-signal luminescence sediment tracing method

Science.gov (United States)

Reimann, Tony

2014-05-01

Optically Stimulated Luminescence (OSL) is commonly used for dating sediments. Luminescence signals build up due to exposure of mineral grains to natural ionizing radiation, and are reset when these grains are exposed to (sun)light during sediment transport and deposition. Generally, luminescence signals can be read in two ways, potentially providing information on the burial history (dating) or the transport history (sediment tracing) of mineral grains. In this study we use a novel luminescence measurement procedure (Reimann et al., submitted) that simultaneously monitors six different luminescence signals from the same sub-sample (aliquot) to infer the transport history of sand grains. Daylight exposure experiments reveal that each of these six signals resets (bleaches) at a different rate, thus allowing to trace the bleaching history of the sediment in six different observation windows. To test the feasibility of luminescence sediment tracing in shallow-marine coastal settings we took eight sediment samples from the pilot mega-nourishment Zandmotor in Kijkduin (South-Holland). This site provides relatively controlled conditions as the morphological evolution of this nourishment is densely monitored (Stive et al., 2013). After sampling the original nourishment source we took samples along the seaward facing contour of the spit that was formed from August 2011 (start of nourishment) to June 2012 (sampling). It is presumed that these samples originate from the source and were transported and deposited within the first year after construction. The measured luminescence of a sediment sample was interpolated onto the daylight bleaching curve of each signal to assign the Equivalent Exposure Time (EET) to a sample. The EET is a quantitative measure of the full daylight equivalent a sample was exposed to during sediment transport, i.e. the higher the EET the longer the sample has been transported or the more efficient it has been exposed to day-light during sediment

Synthesis and characterization of lanthanide-based luminescent nanoparticles: toward new bio-labels

International Nuclear Information System (INIS)

Lechevallier, Severine

2010-01-01

This work deals with the development of luminescent nanoparticles (NPs) suitable as bio-labels. Inorganic NPs have been synthesized, in which luminescent ion (Eu 3+ in most of cases) is substituting ions of the oxide host matrix. NPs of Ln(OH)CO 3 :Eu 3+ (Ln = Y or Gd), Ln 2 O 3 :Eu 3+ , Ln 2 O 2 S:Eu 3+ and SiO 2 :Eu 3+ have been characterized by the way of TGA, WAXS-XRD, TEM, IR and photoluminescence (PL) techniques. The controlled precipitation using urea as precipitating agent is the way chosen and optimized to obtain spherical and monodispersed in size (150±15 nm) NPs. These particles of amorphous lanthanide hydroxycarbonate can directly be used as luminescent bio-labels or after their conversion in oxide or oxi-sulfide. For the silica particles, the synthesis by aerosol pyrolysis has been used. The obtained particles are spherical with a main diameter of 350 nm. In a second step, the surface of the inorganic NPs has been modified, in order to graft amino-reactive functions. Several modification ways have been explored: with APTES (aminopropyltriethoxysilane), with TEOS (tetra-ethoxysilane) and then APTES, or with a TEOS/APTES mixture. The same characterizations techniques have been applied to the modified particles, and chemical analysis, solid state NMR and XPS. DLS and ζ-potential of the NPs dispersed in water have also been measured. These analyses have been completed by the evaluation of the number of accessible amine functions by coupling with FITC (fluorescein isothiocyanate). The direct modification of oxides (Y 2 O 3 or Gd 2 O 3 ) with APTES is the best way, and an homogenous layer of 1 nm with a high number of accessible amine can be graft. Finally, to move toward luminescent bio-labelling in biological medium, the luminescence of the NPs has been observed and analyzed using: - A spectro-fluorimeter, after their dispersion in water; - A fluorescence microscope, on glass slides, under broad band excitation; - A confocal microscope, under laser

GRAVIMETRIC-DETERMINATION OF THE WATER CONCENTRATION IN WHOLE-BLOOD, PLASMA AND ERYTHROCYTES AND CORRELATIONS WITH HEMATOLOGICAL AND CLINICOCHEMICAL PARAMETERS

NARCIS (Netherlands)

LIJNEMA, TH; HUIZENGA, [No Value; JAGER, J; MACKOR, AJ; GIPS, CH

1993-01-01

We have assessed gravimetric methods for determination of intravascular water, established whole blood-, plasma- and erythrocyte water reference values in a healthy volunteer group (n = 97, 48 females) and correlated these variables with 30 simultaneous hematological, clinicochemical and body

Structure and luminescent investigation of new Ln(III)-TTA complexes containing N-methyl-ε-caprolactam as ligand

Energy Technology Data Exchange (ETDEWEB)

Borges, Alex Santos, E-mail: alexb@ifes.edu.br [Coordenadoria de Química e Biologia, IFES, Vitória, ES 29040-780 (Brazil); Caliman, Ewerton Valadares [Coordenadoria de Engenharia Metalúrgica, IFES, Vitória, ES 29040-780 (Brazil); Dutra, José Diogo L. [Departamento de Química Fundamental, UFPE, Recife, PE 50590-470 (Brazil); Da Silva, Jeferson G. [Departamento de Farmácia, UFJF, Governador Valadares, MG 35010-17 (Brazil); Araujo, Maria Helena, E-mail: maria.araujo@pq.cnpq.br [Departamento de Química, UFMG, Belo Horizonte, MG 31270-901 (Brazil)

2016-02-15

The synthesis and photoluminescent properties of Ln(III)-TTA complexes (Ln=Eu(III) and Sm(III) ions; TTA=3-thenoyltrifluoroacetonate) with N-methyl-ε-caprolactam (NMC) are reported. The Ln complexes were characterized by elemental analysis, complexometric titration with EDTA and infrared spectroscopy. The molecular structures of the [Eu(TTA){sub 3}(NMC)(H{sub 2}O)] and [Sm(TTA){sub 3}(NMC)(H{sub 2}O)]·H{sub 2}O compounds were determined by single crystal X-ray crystallography. In these structures, the three TTA molecules are coordinated to the metal in anionic form as bidentate ligands, while the H{sub 2}O and NMC molecules are coordinated to the metal in neutral form as monodentated ligands. The coordination polyhedron around the Ln(III) atom can be described as square antiprismatic molecular geometry. The geometry of the [Eu(TTA){sub 3}(NMC)(H{sub 2}O)] complex was optimized with the Sparkle/RM1 model for Ln(III) complexes, allowing analysis of intramolecular energy transfer processes of the Eu(III) compound. The spectroscopic properties of the 4f{sup 6} intraconfigurational transitions of the Eu(III) complex were then studied experimentally and theoretically. The low value of emission quantum efficiency of {sup 5}D{sub 0} emitting level (η) of Eu(III) ion (ca. 36%) is due to the vibrational modes of the water molecule that act as luminescence quenching. In addition, the luminescence decay curves, the experimental intensity parameters (Ω{sub λ}), lifetimes (τ), radiative (A{sub rad}) and non-radiative (A{sub nrad}) decay rates, theoretical quantum yield (q{sub cal}) were also determined and discussed. - Highlights: • New Ln-TTA complexes with lactam were obtained and their luminescence investigated. • Jablonsky diagram for the Eu(III) complex shows the main channel for the IET process. • Data confirm the potentiality of the Eu(III) complex to produce red luminescence. • LUMPAC has provided useful information on the luminescence of the Eu

Piezoelectrically-induced stress-luminescence phenomenon in CaAl{sub 2}O{sub 4}:Eu{sup 2+}

Energy Technology Data Exchange (ETDEWEB)

Wei, Yongbin [Department of Physics, Zhejiang Normal University, Jinhua 321004 (China); Wu, Zheng, E-mail: wuzheng@zjnu.cn [College of Geography and Environmental Sciences, Zhejiang Normal University, Jinhua 321004 (China); Jia, Yanmin, E-mail: ymjia@zjnu.edu.cn [Department of Physics, Zhejiang Normal University, Jinhua 321004 (China); Liu, Yongsheng [Department of Physics, Shanghai University of Electric Power, Shanghai 200090 (China)

2015-10-15

Piezoelectrically-induced stress-luminescence in the CaAl{sub 2}O{sub 4}:Eu{sup 2+} was investigated. Blue light that was visible to the naked eye could be observed in the dark when a pulse force of ∼7.7 kN was applied to the sample. The intensity of the stress-luminescence strongly depended on the magnitude of the applied force during a pulse cycle. The intensity decreased with repetitive application of pulse stress and was completely recovered after irradiation with ultraviolet light. It is suggested that the stress-luminescence effect in CaAl{sub 2}O{sub 4}:Eu{sup 2+} arises from the piezoelectrically-induced de-trapping of the charge carriers. A CaAl{sub 2}O{sub 4}:Eu{sup 2+} ceramic that exhibits a stress-luminescence effect has potential applications in smart stress optically-sensing devices. - Highlights: • The strong induced stress-luminescence in CaAl{sub 2}O{sub 4}:Eu{sup 2+} was observed. • The stress-luminescent intensity strongly depends on the magnitude of force. • The stress-luminescence could be completely recovered after the UV irradiation. • The strong stress-luminescent effect is potential in stress-light sensors.

Cone Beam X-Ray Luminescence Tomography Imaging Based on KA-FEM Method for Small Animals.

Science.gov (United States)

Chen, Dongmei; Meng, Fanzhen; Zhao, Fengjun; Xu, Cao

2016-01-01

Cone beam X-ray luminescence tomography can realize fast X-ray luminescence tomography imaging with relatively low scanning time compared with narrow beam X-ray luminescence tomography. However, cone beam X-ray luminescence tomography suffers from an ill-posed reconstruction problem. First, the feasibility of experiments with different penetration and multispectra in small animal has been tested using nanophosphor material. Then, the hybrid reconstruction algorithm with KA-FEM method has been applied in cone beam X-ray luminescence tomography for small animals to overcome the ill-posed reconstruction problem, whose advantage and property have been demonstrated in fluorescence tomography imaging. The in vivo mouse experiment proved the feasibility of the proposed method.

Highly Selective Polypyrrole MIP-Based Gravimetric and Electrochemical Sensors for Picomolar Detection of Glyphosate

Directory of Open Access Journals (Sweden)

Zouhour Mazouz

2017-11-01

Full Text Available There is a global debate and concern about the use of glyphosate (Gly as an herbicide. New toxicological studies will determine its use in the future under new strict conditions or its replacement by alternative synthetic or natural herbicides. In this context, we designed biomimetic polymer sensing layers for the selective molecular recognition of Gly. Towards this end, complementary surface acoustic wave (SAW and electrochemical sensors were functionalized with polypyrrole (PPy-imprinted polymer for the selective detection of Gly. Their corresponding limits of detection were on the order of 1 pM, which are among the lowest values ever reported in literature. The relevant dissociation constants between PPy and Gly were estimated at [Kd1 = (0.7 ± 0.3 pM and Kd2 = (1.6 ± 1.4 µM] and [Kd1 = (2.4 ± 0.9 pM and Kd2 = (0.3 ± 0.1 µM] for electrochemical and gravimetric measurements, respectively. Quantum chemical calculations permitted to estimate the interaction energy between Gly and PPy film: ΔE = −145 kJ/mol. Selectivity and competitivity tests were investigated with the most common pesticides. This work conclusively shows that gravimetric and electrochemical results indicate that both MIP-based sensors are perfectly able to detect and distinguish glyphosate without any ambiguity.

Synthesis of yttrium silicate luminescent materials by sol-gel method

International Nuclear Information System (INIS)

Arkhipov, D.V.; Vasina, O.Yu.; Popovich, N.V.; Galaktionov, S.S.; Soshchin, N.P.

1996-01-01

Several yttrium-silicate composition with Y 2 O 3 content within 44-56% have been synthesized. it is ascertained that employment of sol-gel technique permits preparation of luminescent materials on yttrium silicate basis, which compare favourably with bath-produced specimens. The influence of phase composition of sol-gel phosphors on basic performance indices: intensity and luminescence spectrum, has been analyzed

Neutron dosimetry using optically stimulated luminescence

International Nuclear Information System (INIS)

Miller, S.D.; Eschbach, P.A.

1991-06-01

The addition of thermoluminescent (TL) materials within hydrogenous matrices to detect neutron-induced proton recoils for radiation dosimetry is a well-known concept. Previous attempts to implement this technique have met with limited success, primarily due to the high temperatures required for TL readout and the low melting temperatures of hydrogen-rich plastics. Research in recent years at Pacific Northwest laboratories (PNL) has produced a new Optically Stimulated Luminescence (OSL) technique known as the Cooled Optically Stimulated Luminescence (COSL) that offers, for the first time, the capability of performing extremely sensitive radiation dosimetry at low temperatures. In addition to its extreme sensitivity, the COSL technique offers multiple readout capability, limited fading in a one-year period, and the capability of analyzing single grains within a hydrogenous matrix. 4 refs., 10 figs

Blue-green luminescent CdZnSeS nanocrystals synthesized with activated alkyl thiol

International Nuclear Information System (INIS)

Xia Xing; Liu Zuli; Du Guihuan; Li Yuebin; Ma Ming; Yao Kailun

2012-01-01

Semiconductor nanocrystals with blue-green luminescence are potentially useful in various applications, but the preparation has not been easy compared to regular semiconductor nanocrystals with emission in the orange-red range. In this research alloyed CdZnSeS nanocrystals with luminescence covering the wavelength range from 430 to 560 nm are obtained by a one-step method with the assistance of alkyl thiol compound 1-dodecanethiol, which serves both as the sulfur source and surface ligand. The luminescence of CdZnSeS nanocrystals can be tuned from blue to green by altering the Cd:Zn molar ratio. Besides, the amount of 1-dodecanethiol in the reaction mixture can influence the emission wavelength by restricting the growth of nanocrystals. The dual control of both particle composition and size has enabled the tuning of luminescence to cover the blue-green spectral window. This research presents a convenient method to synthesize nanocrystals with tunable blue-green emission; these materials can be useful in advanced technologies such as photovoltaics, lighting and display. - Highlights: → Obtained blue-green luminescent nanocrystals by a one-step process. → Alkyl thiol used as a sulfur source and a surface stabilizer to control particle size. → Luminescence color of NCs could be easily tuned by changing their composition and particle size simultaneously.

New polymers containing BF2-benzoylacetonate groups. Synthesis, luminescence, excimer and exciplex formation

International Nuclear Information System (INIS)

Fedorenko, Elena V.; Mirochnik, Anatolii G.; Beloliptsev, Anton Yu.

2017-01-01

In the present study, a new synthetic method for the functionalization of polystyrene (PS) and (styrene-methyl methacrylate) copolymer has been developed. Using the new method, polymers containing BF 2 -benzoylacetonate groups have been obtained through double acylation by acetic anhydride with boron trifluoride. Luminescence of the produced polymers in solutions and films has been studied. Quantum yields of polymer solution luminescence are significantly higher than those of the low-molecular-weight analog – boron difluoride benzoylacetonate. For the polymer, in which styrene fragments are separated by methyl methacrylate groups, at low concentrations of the polymer in solution one observes the monomer luminescence of BF 2 -benzoylacetonate groups, while at high concentrations – the excimer luminescence. In case of PS-based polymers, in which BF 2 -benzoylacetonate groups and phenyl rings are not separated, in diluted solutions one observes the fluorescence of the intramolecular exciplexes, while at the concentration increase – the luminescence of intermolecular exciplexes. The ability of excimer formation is responsible for the increased photostability of the produced polymers. - Highlights: •Polymers containing BF 2 -benzoylacetonate groups have been synthesized. •Luminescence of the produced polymers in solutions and films has been studied. •Formation of excimers and exciplexes in solution has been revealed. •Formation of excimers in films increases their photostability.

Porous glasses as a host of luminescent materials, their applications and site selective determination

Energy Technology Data Exchange (ETDEWEB)

Reisfeld, Renata, E-mail: renata.reisfeld@mail.huji.ac.il [Institute of Chemistry, Hebrew University of Jerusalem, Givat-Ram, Jerusalem 91904 (Israel); Jasinska, Bozena [Institute of Physics, Maria Curie-Sklodowska University, Pl. M. Curie-Skłodowsskiej 1, 20-031 Lublin (Poland); Levchenko, Viktoria [Institute of Chemistry, Hebrew University of Jerusalem, Givat-Ram, Jerusalem 91904 (Israel); Gorgol, Marek [Institute of Physics, Maria Curie-Sklodowska University, Pl. M. Curie-Skłodowsskiej 1, 20-031 Lublin (Poland); Saraidarov, Tsiala; Popov, Inna [Institute of Chemistry, Hebrew University of Jerusalem, Givat-Ram, Jerusalem 91904 (Israel); Antropova, Tatiana [I. V. Grebenshchikov Institute of the Chemistry of Silicates, Russian Academy of Sciences, Nab. Makarova, 2, Liter B, Saint-Petersburg 199034 (Russian Federation); Rysiakiewicz-Pasek, Ewa [Institute of Physics, Wroclaw University of Technology, W. Wyspianskiego 27, 50-370 Wroclaw (Poland)

2016-01-15

The site selective distribution of pore sizes in pure porous glasses and glasses doped by a luminescent colorant is determined by luminescent spectroscopy, SEM, SAXS and PALS. The potential applications of the studied materials as environmental and biological sensors are outlined. We suggest how luminescent porous glasses doped by complexes of Gd can act as solid scintillators in tracing elementary particles like neutrino. - Highlights: • Porous glasses are a medium for large number of luminescent materials. • Size distribution of empty and filled pores is studied. • The validity of data obtained by different methods is analyzed.

Luminescence recognition of different organophosphorus pesticides by the luminescent Eu(III)-pyridine-2,6-dicarboxylic acid probe

Energy Technology Data Exchange (ETDEWEB)

Azab, Hassan A., E-mail: azab2@yahoo.com [Chemistry Department, Faculty of Science, Suez Canal University, Ismailia 41522 (Egypt); Duerkop, Axel [Institute of Analytical Chemistry, Chemo and Biosensors, Regensburg University, D-93040 Regensburg (Germany); Anwar, Z.M.; Hussein, Belal H.M.; Rizk, Moustafa A.; Amin, Tarek [Chemistry Department, Faculty of Science, Suez Canal University, Ismailia 41522 (Egypt)

2013-01-08

Highlights: Black-Right-Pointing-Pointer Europium (III) luminescence quenching has been used for sensing organophosphorous pesticides. Black-Right-Pointing-Pointer Four guest pesticides chlorfenvinphos, malathion, azinphos, and paraxon ethyl were used. Black-Right-Pointing-Pointer A sensitive rapid, cheap direct method for the determination of the pesticides has been developed. Black-Right-Pointing-Pointer The method was applied to the determination of the OPs in tap, river, mineral, and waste waters. - Abstract: Luminescence quenching of a novel long lived Eu(III)-pyridine-2,6-dicarboxylic acid probe of 1:2 stoichiometric ratio has been studied in 0.10 volume fraction ethanol-water mixture at pH 7.5 (HEPES buffer) in the presence of the organophosphorus pesticides chlorfenvinphos (P1), malathion (P2), azinphos (P3), and paraxon ethyl (P4). The luminescence intensity of Eu(III)-(PDCA){sub 2} probe decreases as the concentration of the pesticide increases. It was observed that the quenching due to P3 and P4 proceeds via both diffusional and static quenching processes. Direct methods for the determination of the pesticides under investigation have been developed using the luminescence quenching of Eu(III)-pyridine-2,6-dicarboxylic acid probe in solution. The linear range for determination of the selected pesticides is 1.0-35.0 {mu}M. The detection limits were 0.24-0.55 {mu}M for P3, P4, and P1 and 2.5 {mu}M for P2, respectively. The binding constants (K), and thermodynamic parameters of the OPs with Eu(III)-(PDCA){sub 2} were evaluated. Positive and negative values of entropy ({Delta}S) and enthalpy ({Delta}H) changes for Eu(III)-(PDCA){sub 2}-P1 ternary complex were calculated. As the waters in this study do not contain the above mentioned OPs over the limit detectable by the method, a recovery study was carried out after the addition of the adequate amounts of the organophosphorus pesticides under investigation.

Luminescence lifetimes in natural quartz annealed beyond its second phase inversion temperature

International Nuclear Information System (INIS)

Chithambo, M.L.

2015-01-01

The influence of annealing, irradiation dose, preheating and measurement temperature on luminescence lifetimes has been studied in quartz annealed at 1000 °C. The measurements were supplemented by studies on quartz annealed at 900 and 800 °C. Lifetimes increase with dose as well as with temperature and duration of annealing between 800 and 1000 °C. Preheating produces the same effect. The changes are accounted for in terms of hole-transfer from the non-radiative luminescence centre to and between radiative centres. The influence of measurement temperature on lifetimes depends on whether the stimulation is carried out from ambient to 200 °C or otherwise. This result is unlike that in quartz annealed at or below 500 °C where lifetimes are independent of the direction of heating. In particular, lifetimes decrease monotonically when measurements are made from 20 to 200 °C but not when recorded from 200 to 20 °C. The latter produces a pattern resembling that in quartz annealed up to 500 °C. The results are concluded as evidence of thermal effects on separate luminescence centres. In support of this, different values of the activation energy for thermal quenching were found for each supposed luminescence centre. The change of the corresponding luminescence intensity with temperature is also qualitatively consistent with this notion. - Highlights: • Luminescence lifetimes in natural quartz annealed beyond its second phase inversion temperature is reported. • Lifetimes increase with dose, annealing between 800 and 1000 °C, and preheating. • Lifetimes under stimulation temperature are affected by direction of heating. • Changes are accounted for in terms of hole-transfer luminescence centres.

Structural, optical, thermal and Photocatalytic properties of ZnO nanoparticles of Betel Leave by using Green synthesis method

Directory of Open Access Journals (Sweden)

S. Rajesh

2016-07-01

Full Text Available In this present study reports the green synthesis of zinc oxide nanoparticles using Betel leaf extracts and zinc acetate. The functionalization of ZnO particles through Betel leaf extract mediated bio reduction of ZnO was investigated through X-ray diffraction, Field emission scanning electron microscopy, photoluminescence, thermal gravimetric-differential thermal analysis, hexagonal shaped ZnO-nanoparticles  with  size  about  50 nm  were synthesized and characterized using X-ray diffraction analysis. The diameter of the nanoparticles in the range of 50 nm was found from scanning electron microscopy study. Photo luminescence study reveals the blue emission at 463nm respectively. hermal gravimetric-differential thermal analysis show that the observed at 480oC, indicating that no decomposition occurs above this temperature. The photocatalytic degradation of methylene blue dye was examined using ZnO nanoparticles under solar as well as ultra violet light irradiation of the MB dye. The  method  stands out primarily due to the fact that it is eco-friendly and shuts down the demerits of conventional  physical  and  chemical  methods. These particles are anticipated to have extensive applications in various industries.

Alternatives to the gravimetric method for quantification of diesel particulate matter near the lower level of detection.

Science.gov (United States)

Swanson, Jacob; Kittelson, David; Pui, David; Watts, Winthrop

2010-10-01

This paper is part of the Journal of the Air & Waste Management Association's 2010 special issue on combustion aerosol measurements. The issue is a combination of papers that synthesize and evaluate ideas and perspectives that were presented by experts at a series of workshops sponsored by the Coordinating Research Council that aimed to evaluate the current and future status of diesel particulate matter (DPM) measurement. Measurement of DPM is a complex issue with many stakeholders, including air quality management and enforcement agencies, engine manufacturers, health experts, and climatologists. Adoption of the U.S. Environmental Protection Agency 2007 heavy-duty engine DPM standards posed a unique challenge to engine manufacturers. The new standards reduced DPM emissions to the point that improvements to the gravimetric method were required to increase the accuracy and the sensitivity of the measurement. Despite these improvements, the method still has shortcomings. The objectives of this paper are to review the physical and chemical properties of DPM that make gravimetric measurement difficult at very low concentrations and to review alternative metrics and methods that are potentially more accurate, sensitive, and specific. Particle volatility, size, surface area, and number metrics are considered, as well as methods to quantify them. Although the authors believe that an alternative method is required to meet the needs of engine manufacturers, the methods reviewed in the paper are applicable to other areas where the gravimetric method detection limit is approached and greater accuracy and sensitivity are required. The paper concludes by suggesting a method to measure active surface area, combined with a method to separate semi-volatile and solid fractions to further increase the specificity of the measurement, has potential for reducing the lower detection limit of DPM and enabling engine manufacturers to reduce DPM emissions in the future.

Gravimetric determination of carbon in uranium-plutonium carbide materials

International Nuclear Information System (INIS)

Kavanaugh, H.J.; Dahlby, J.W.; Lovell, A.P.

1979-12-01

A gravimetric method for determining carbon in uranium-plutonium carbide materials was developed to analyze six samples simultaneously. The samples are burned slowly in an oxygen atmosphere at approximately 900 0 C, and the gases generated are passed through Schuetze's oxidizing reagent (iodine pentoxide on silica gel) to assure quantitative oxidation of the CO to CO 2 . The CO 2 is collected on Ascarite and weighed. This method was tested using a tungsten carbide reference material (NBS-SRM-276) and a (U,Pu)C sample. For 42 analyses of the tungsten carbide, which has a certified carbon content of 6.09%, an average value of 6.09% was obtained with a standard deviation of 0.01 7 % or a relative standard deviation of 0.28%. For 17 analyses of the (U,Pu)C sample, an average carbon content of 4.97% was found with a standard deviation of 0.01 2 % or a relative standard deviation of 0.24%

Novel Luminescent Multilayer Films Containing π-Conjugated Anionic Polymer with Electronic Microenvironment

Directory of Open Access Journals (Sweden)

Tianlei Wang

2016-09-01

Full Text Available Layered double hydroxides (LDHs, luminescent π-conjugated anionic polymer and montmorillonite (MMT were orderly assembled into luminescent multilayer films via layer-by-layer self-assembly method. The electronic microenvironment (EME, the structure of which is like a traditional capacitor, can be constructed by exfoliated LDHs or MMT nanosheets. In addition, the rigid inorganic laminated configuration can offer stable surroundings between the interlayers. As a result, we conclude that EME can extend the luminescent lifespans of multilayer films substantially, due to affecting relaxation times of π-conjugated anionic polymer. Consequently, because of the remarkable impact on better photoemission behaviors of luminescent π-conjugated anionic polymer, EME assembled by LDHs or MMT nanosheets have had high hopes attached to them. They are expected to have the potential for designing, constructing, and investigating novel light-emitting thin films.

Advances in luminescence instrument systems

DEFF Research Database (Denmark)

Bøtter-Jensen, L.; Bulur, E.; Duller, G.A.T.

2000-01-01

We report on recent advances in the development of luminescence measurement systems and techniques at Riso. These include: (1) optical stimulation units based on new-generation powerful blue light (470 nm) emitting diodes providing up to 28 mW/cm(2) for OSL measurements; (2) an infrared (830 nm...

Luminescence in Sulfides: A Rich History and a Bright Future

Directory of Open Access Journals (Sweden)

Philippe F. Smet

2010-04-01

Full Text Available Sulfide-based luminescent materials have attracted a lot of attention for a wide range of photo-, cathodo- and electroluminescent applications. Upon doping with Ce3+ and Eu2+, the luminescence can be varied over the entire visible region by appropriately choosing the composition of the sulfide host. Main application areas are flat panel displays based on thin film electroluminescence, field emission displays and ZnS-based powder electroluminescence for backlights. For these applications, special attention is given to BaAl2S4:Eu, ZnS:Mn and ZnS:Cu. Recently, sulfide materials have regained interest due to their ability (in contrast to oxide materials to provide a broad band, Eu2+-based red emission for use as a color conversion material in white-light emitting diodes (LEDs. The potential application of rare-earth doped binary alkaline-earth sulfides, like CaS and SrS, thiogallates, thioaluminates and thiosilicates as conversion phosphors is discussed. Finally, this review concludes with the size-dependent luminescence in intrinsic colloidal quantum dots like PbS and CdS, and with the luminescence in doped nanoparticles.

High-temperature peaks of thermostimulated luminescence in the ammonium halogens

International Nuclear Information System (INIS)

Kim, L.M.; Musenova, Eh.K.; Mukhamedrakhimov, K.U.

2003-01-01

The ammonium halogen crystals (AHC) are the close analogs of the alkali halogen crystals by the type of chemical bonds and crystal lattice structure. The ammonium halogen after irradiation by X-rays within 80-300 K range have two peaks of thermo-stimulation luminescence. Its maximums in dependence of anions type are in the 110-120 K and 170-180 K ranges. The first range is related with activation of auto-localized holes migration, and the second one - with the NH 3 + defects decay. Experimentally is established, that the pure ammonium halogens have memory about the previous irradiation at heating up to 300 K. After repeat irradiation the recombination luminescence high-temperature peak's shoulder is appearing. The second luminescence peak's shoulder revealing does not depend on the impurity center nature. It is known, that in the AHC there is the next thermo-stimulation luminescence peak within 340-360 K. The thermal annealing of this peak leads to the memory effect disappearance. So, the observing phenomenon is related with own defect of the matrix in the cation sublattice. Experimentally is established, that at a room temperature the AHC memorizing about previous irradiation during 20 h

Synthesis, crystal structure and luminescence properties of lanthanide coordination polymers with a new semirigid bridging thenylsalicylamide ligand

International Nuclear Information System (INIS)

Song, Xue-Qin; Wang, Li; Zhao, Meng-Meng; Wang, Xiao-Run; Peng, Yun-Qiao; Cheng, Guo-Quan

2013-01-01

Two new lanthanide coordination polymers based on a semirigid bridging thenylsalicylamide ligand ([Ln 2 L 3 (NO 3 ) 6 ]·(C 4 H 8 O 2 ) 2 ) ∞ were obtained and characterized by elemental analysis, X-ray diffraction, IR and TGA measurements. The two compounds are isostructure and possess one dimensional trapezoid ladder-like chain built up from the connection of isolated LnO 3 (NO 3 ) 3 polyhedra (distorted monocapped antisquare prism) through the ligand. The photoluminescence analysis suggest that there is an efficient ligand-to-Ln(III) energy transfer in Tb(III) complex and the ligand is an efficient “antenna” for Tb(III). From a more general perspective, the results demonstrated herein provide the possibility of controlling the formation of the desired lanthanide coordination structure to enrich the crystal engineering strategy and enlarge the arsenal for developing excellent luminescent lanthanide coordination polymers. - Graphical abstract: We present herein one dimensional lanthanide coordination polymers of a new semirigid exo-bidentate ligand which not only display interesting structures but also possess strong luminescence properties. Display Omitted - Highlights: • We present lanthanide coordination polymers of a new semirigid exo-bidentate ligand. • The lanthanide coordination polymers exhibit interesting structures. • The luminescent properties of Tb(III) complexes are discussed in detail

Ab initio calculations of cross luminescence materials

International Nuclear Information System (INIS)

Kanchana, V.

2016-01-01

Abintio calculations have been performed to study the structural, electronic, and optical properties of ABX 3 (A=alkali, B=alkaline-earth, and X=halide) compounds. The ground state properties are calculated using the pseudopotential method with the inclusion of van der Waals interaction, which we find inevitable in reproducing the experimental structure properties in alkali iodides because of its layered structure. All calculations were performed using the Full-Potential Linearized Augmented Plane Wave method. The band structures are plotted with various functionals and we find the newly developed Tran and Blaha modified Becke-Johnson potential to improve the band gap significantly. The optical properties such as complex dielectric function, refractive index, and absorption spectra are calculated which clearly reveal the optically isotropic nature of these materials though being structurally anisotropic, which is the key requirement for ceramic scintillators. Cross luminescence materials are very interesting because of its fast decay. One of the major criteria for the cross luminescence to happen is the energy difference between valence band and next deeper core valence band being lesser when compared to energy gap of the compound, so that radiative electronic transition may occur between valence band and core valence band. We found this criteria to be satisfied in all the studied compounds leading to cross luminescence except for KSrI 3 , RbSrI 3 . The present study suggest that among the six compounds studied, CsSrI 3 , CsMgCl 3 , CsCaCl 3 , and CsSrCl 3 compounds are cross luminescence materials, which is well explained from the band structure, optical properties calculations. Chlorides are better scintillators that iodides and CsMgCl 3 is found to be promising one among the studied compounds. Apart from these materials we have also discussed electronic structure and optical properties of other scintillator compounds. (author)

Process for producing a self luminescent material

Energy Technology Data Exchange (ETDEWEB)

Abe, E

1962-01-28

A self luminescent material is produced by a process comprising applying a hydroxide or fluoride of promethium-147 suspended in a medium of paraffinic acid to the surface of a fluorescent body. Promethium-147 decays with a half-life of 2.6 years and emits beta-rays but not alpha- and gamma-rays so that it is suitable for manufacturing self luminescent materials. A chloride of promethium-147 cannot be employed because its structure is destroyed by acids. Although fluorides and hydroxides of promethium-147 are difficult to mix with the fluorescent body material, they become mixable when paraffinic acids containing from 12 to 20 carbon atoms, (for example, steric acid, palmitic acid and margaric acid) are used as a medium. In embodiments, the self luminescent materials are prepared by either neutralization of a promethium-147 chloride solution having a specific radioactivity of 1.2 c/cc. with an ammonium hydroxide solution to form gelatinous hydroxide, or the reaction of a promethium-147 chloride solution with H/sub 2/SiF/sub 6/ by heating at 80/sup 0/C to form a fluoride of promethium-147. The products have a specific radioactivity of 8 to 12 mc/g. These products are suspended in vehicles of polystyrene and methacrylic resin to produce the self luminescent coating materials. Tests show that the initical brightness is comparatively high, the decreasing rate of brightness is small, no blackening effects by alpha-rays occur and costs are low. The brightness of the coating containing promethium-147 is 82-85 after 5 days, 100-105 after 100 days and 82-92 after 180 days. With respect to the coating containing radium the values are 31-70 after 5 days, 28-49 after 100 days and 19-31 after 180 days.

Luminescence properties of Ce3+ doped gadolinium-calcium-silicaborate glass scintillator

International Nuclear Information System (INIS)

Park, J.M.; Ha, D.H.; Kaewjeang, S.; Maghanemi, U.; Kothan, S.; Kaewkhao, J.; Kim, H.J.

2016-01-01

In this work, the Ce 3+ doped gadolinium-calcium-silicaborate glass scintillators of the composition ratio 25Gd 2 O 3 :10CaO:10SiO 2 :(55−x)B 2 O 3 :xCeF 3 , have been fabricated by using the melt-quenching technique. The doping concentration of the Ce 3+ was varied from 0.05 mol% to 2.5 mol%. The 4f-5d transition of the Ce 3+ allowed scintillation with a fast decay time. The absorption spectrum, X-ray induced emission spectrum, photo luminescence spectrum, laser luminescence spectrum and decay time of the scintillators were measured for studying the luminescence properties. From the X-ray induced emission spectrum result, we checked the trend between doping concentration and light yield. The laser induced luminescence spectrum was measured while changing the temperature from 300 K to 10 K. We also measured the decay time by using the laser excitation of the 0.15 mol% Ce 3+ doped glass scintillator. - Highlights: • Ce 3+ doped gadolinium-calcium-silicaborate glass scintillators were developed. • Glass is easily fabricated with large sizes and various doping materials. • The luminescence properties are studied by using various radiation sources. • The light yield and decay time were measured at low temperature. • One decay time component is found.

Temperature and Pressure Sensors Based on Spin-Allowed Broadband Luminescence of Doped Orthorhombic Perovskite Structures

Science.gov (United States)

Eldridge, Jeffrey I. (Inventor); Chambers, Matthew D. (Inventor)

2014-01-01

Systems and methods that are capable of measuring pressure or temperature based on luminescence are discussed herein. These systems and methods are based on spin-allowed broadband luminescence of sensors with orthorhombic perovskite structures of rare earth aluminates doped with chromium or similar transition metals, such as chromium-doped gadolinium aluminate. Luminescence from these sensors can be measured to determine at least one of temperature or pressure, based on either the intense luminescence of these sensors, even at high temperatures, or low temperature techniques discussed herein.

Luminescence properties of Nd3+-doped Y2O3 nanoparticles in organic media

International Nuclear Information System (INIS)

Cui, Xiaoxia; Hou, Chaoqi; Lu, Jiabao; Gao, Chao; Wei, Wei; Peng, Bo

2011-01-01

Nd 3+ -doped yttrium oxide nanoparticles (Y 2 O 3 :Nd) with cubic phase were obtained successfully by a glycine-nitrate solution combustion method. The results of Fourier transform infrared spectra (FTIR) showed that the -OH groups residing on the nanoparticles surfaces were reduced effectively by modifying with capping agent. The modified Y 2 O 3 :Nd nanoparticles displayed good monodispersity and excellent luminescence in N,N-dimethylformamide (DMF) solvent. Some optical parameters were calculated by Judd-Ofelt analysis based on absorption and fluorescence spectra. A relative large stimulated emission cross section, 1.7 x 10 -20 cm 2 , of the 4 F 3/2 → 4 I 11/2 transition was calculated. Theses results show that the modified Y 2 O 3 :Nd nanoparticles display good luminescence behavior in organic media. (orig.)

Development of a ratiometric time-resolved luminescence sensor for pH based on lanthanide complexes

International Nuclear Information System (INIS)

Liu Mingjing; Ye Zhiqiang; Xin Chenglong; Yuan Jingli

2013-01-01

Highlights: ► A lanthanide complex-based ratiometric luminescent pH sensor was developed. ► The sensor can luminously respond to pH in weakly acidic to neutral media. ► The sensor can be used for monitoring pH with time-resolved luminescence mode. ► The sensor can be also used for monitoring pH with absorbance mode. ► The utility of the sensor for the luminescent cell imaging was demonstrated. - Abstract: Time-resolved luminescence bioassay technique using lanthanide complexes as luminescent probes/sensors has shown great utilities in clinical diagnostics and biotechnology discoveries. In this work, a novel terpyridine polyacid derivative that can form highly stable complexes with lanthanide ions in aqueous media, (4′-hydroxy-2,2′:6′,2′′-terpyridine-6,6′′-diyl) bis(methylenenitrilo) tetrakis(acetic acid) (HTTA), was designed and synthesized for developing time-resolved luminescence pH sensors based on its Eu 3+ and Tb 3+ complexes. The luminescence characterization results reveal that the luminescence intensity of HTTA–Eu 3+ is strongly dependent on the pH values in weakly acidic to neutral media (pK a = 5.8, pH 4.8–7.5), while that of HTTA–Tb 3+ is pH-independent. This unique luminescence response allows the mixture of HTTA–Eu 3+ and HTTA–Tb 3+ (the HTTA–Eu 3+ /Tb 3+ mixture) to be used as a ratiometric luminescence sensor for the time-resolved luminescence detection of pH with the intensity ratio of its Tb 3+ emission at 540 nm to its Eu 3+ emission at 610 nm, I 540nm /I 610nm , as a signal. Moreover, the UV absorption spectrum changes of the HTTA–Eu 3+ /Tb 3+ mixture at different pHs (pH 4.0–7.0) also display a ratiometric response to the pH changes with the ratio of absorbance at 290 nm to that at 325 nm, A 290nm /A 325nm , as a signal. This feature enables the HTTA–Eu 3+ /Tb 3+ mixture to have an additional function for the pH detection with the absorption spectrometry technique. For loading the complexes into the

Luminescence properties of uranyl-acetate species

Energy Technology Data Exchange (ETDEWEB)

Brinkmann, Hannes; Moll, Henry [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Inst. of Resource Ecology; Stumpf, Thorsten [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Biogeochemistry

2017-06-01

Time-resolved laser-induced fluorescence spectroscopy (TRLFS) was applied to characterize uranium(VI)- acetate species based on their luminescence properties. In contrast to previous interpretations, no indications were detected for the existence of the 1: 3 complex.

Luminescence and energy transfer processes in rare earth compounds

International Nuclear Information System (INIS)

Vliet, J.P.M. van.

1989-01-01

In this thesis some studies are presented of the luminescence and energy transfer in compounds containing Eu 3+ , Pr 3+ and Gd 3+ ions. Ch. 2 deals with the energy migration in the system Gd 1 - xEu x(IO 3) 3. In ch 3 the luminescence properties of the Pr 3+ ion in the system La 1 - xPr xMgAl 1 10 1 9 are reported. Ch. 4 discusses the luminescence properties of alkali europium double tungstates and molybdates AEuW 20 8 and AEuMo 20 * (A + = alkali metal atom). The luminiscence and energy migration characteristics of the isostructural system LiGd 1 - xEu xF 4 and Gd 1 - xEu xNbO 4 are reported in ch. 5. In ch. 6 the mechanism of energy migration in (La,Gd)AlO 3 and (Gd,Eu)AlO 3 is discussed. Ch. 7 deals with the system Na 5(Gd,Eu) (WO 4) 4. In ch. 8 the luminescence and energy transfer properties of two europium tellurite anti-glass phases are reported. The two phases are Eu 1 . 7 9TeO x, which has a pseudotetragonal structure, and Eu 1 . 0 6TeO x, which has a monoclinic, ordered structure. (author). 201 refs.; 39 figs.; 8 tabs

Application of Quantum Dot nanocrystal in Luminescent solar concentrators

Science.gov (United States)

Bakhoda, Shokoufeh; Khalaji Assadi, Morteza; Ahmadi Kandjani, Sohrab; Kayiem, Hussain H. Al; Hussain Bhat, Aamir

2018-03-01

The basic design of luminescent solar concentrator is a transparent plate doped with an appropriate luminescent material (organic dyes, quantum dots), which is able to absorb sunlight (direct and diffuse), and then guides photons produced by photoluminescence to its narrow edges where they are converted by photovoltaic cells. Unfortunately, LSCs have suffered from numerous efficiency losses. Therefore, new luminescent species and novel approaches are needed for its practical application. This paper deals with investigation of nonhazardous, environmental friendly luminescent species include CuInS2/ZnS core/shell QDs. The CuInS2/ZnS QDs possess advantages of Stocks shift as large as more than 130 nm and high photoluminescence quantum yield of 80%. The paper presents the effect of large stock shift CuInS2/ZnS QDs on reducing the reabsorption losses in LSC by using experimental investigation. The LSC sheets were fabricated by dispersing CuInS2/ZnS QDs particles in a polymethylmethacrylate waveguide. A series of LSCs (dimension 4.0 cm × 3.0 cm × 0.3cm) with different CuInS2/ZnS QDs particles concentration (0.015 and 0.03 wt.%) were fabricated and their optical properties (absorptions/emissions) were characterized. The results show that the CuInS2/ZnS QDs-LSC provides a promising way for the reduction of reabsorption losses in LSCs.

[Evaluation of the AOAC 985.29 enzimic gravimetric method for determination of dietary fiber in oat and corn grains].

Science.gov (United States)

da Silva, Leila Picolli; Ciocca, Maria de Lourdes Santorio; Furlong, Eliana Badiale

2003-12-01

The precision attributes and use of the enzymatic-gravimetric method of Prosky et al. (1992) (AOAC 985.29) were evaluated using corn (BR 5202 Pampa) and oat (UFRGS 15) samples. The effect of laboratory batches carried out in different days were evaluated in six laboratory batches, using for each material one duplicate for total fiber (FT) determination, one duplicate for insoluble fiber (FI) determination and blank ones for FT and for FI (both in duplicate). In order to characterize repetitive aspects, five other FT and FI determinations added to each sample were evaluated, summing up 11 data. The low coefficients of variation in the first six batches were considered acceptable as an expression of expected total intralaboratory variation. The repetitive of the method was considered good for FT determinations (CVs gravimetric corrections varies with the kind of the sample and is especially influenced by the protein content.

Interactions between bicarbonate, potassium, and magnesium, and sulfur-dependent induction of luminescence in Vibrio fischeri.

Science.gov (United States)

Tabei, Yosuke; Era, Mariko; Ogawa, Akane; Morita, Hiroshi

2012-06-01

In spite of its central importance in research efforts, the relationship between seawater compounds and bacterial luminescence has not previously been investigated in detail. Thus, in this study, we investigated the effect of cations (Na(+) , K(+) , NH(4) (+) , Mg(2+) , and Ca(2+) ) and anions (Cl(-) , HCO(3) (-) , CO(3) (2-) , and NO(3) (-) ) on the induction of both inorganic (sulfate, sulfite, and thiosulfate) and organic (L-cysteine and L-cystine) sulfur-dependent luminescence in Vibrio fischeri. We found that HCO(3) (-) (bicarbonate) and CO(3) (2-) (carbonate), in the form of various compounds, had a stimulatory effect on sulfur-dependent luminescence. The luminescence induced by bicarbonate was further promoted by the addition of magnesium. Potassium also increased sulfur-dependent luminescence when sulfate or thiosulfate was supplied as the sole sulfur source, but not when sulfite, L-cysteine, or L-cystine was supplied. The positive effect of potassium was accelerated by the addition of magnesium and/or calcium. Furthermore, the additional supply of magnesium improved the induction of sulfite- or L-cysteine-dependent luminescence, but not the l-cystine-dependent type. These results suggest that sulfur-dependent luminescence of V. fischeri under nutrient-starved conditions is mainly controlled by bicarbonate, carbonate, and potassium. In addition, our results indicate that an additional supply of magnesium is effective for increasing V. fischeri luminescence. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Single fiber temperature probe configuration using anti-Stokes luminescence from Cr:GdAlO3

Science.gov (United States)

Eldridge, Jeffrey I.

2018-06-01

Single-photon excitation of anti-Stokes-shifted emission from a thermographic phosphor allows operation of a luminescence decay-based single fiber temperature probe with negligible interference from background fiber-generated Raman scattering. While single fiber probe configurations for luminescence-based fiber optic thermometers offer advantages of simple design, compactness, and superior emission light collection efficiency, their effective use has been limited by interference from Raman scattering in the fiber probe and excitation delivery fiber that produces distortion of the luminescence decay that follows the excitation pulse. The near elimination of interference by background fiber-generated Raman scattering was demonstrated by incorporating a Cr-doped GdAlO3 (Cr:GdAlO3) thermographic phosphor as the sensing element at the end of a single fiber luminescence decay-based thermometer and detecting anti-Stokes-shifted luminescence centered at 542 or 593 nm produced by 695 nm excitation. Measurements were performed using both silica (up to 1150 °C) and single-crystal YAG (up to 1200 °C) fiber-based thermometers. Selection of emission detection centered at 542 nm greatly benefited the YAG fiber probe measurements by practically eliminating detection of otherwise significant luminescence from Cr3+ impurities in the YAG fiber. For both the silica and YAG fiber probes, the relative benefit of adopting single-photon excitation of anti-Stokes-shifted luminescence was evaluated by comparison with results obtained by conventional 532 nm excitation of Stokes-shifted luminescence.

Evaluation of one-step luminescent cyanoacrylate fuming.

Science.gov (United States)

Khuu, Alicia; Chadwick, Scott; Spindler, Xanthe; Lam, Rolanda; Moret, Sébastien; Roux, Claude

2016-06-01

One-step luminescent cyanoacrylates have recently been introduced as an alternative to the conventional cyanoacrylate fuming methods. These new techniques do not require the application of a luminescent post-treatment in order to enhance cyanoacrylate-developed fingermarks. In this study, three one-step polymer cyanoacrylates: CN Yellow Crystals (Aneval Inc.), PolyCyano UV (Foster+Freeman Ltd.) and PECA Multiband (BVDA), and one monomer cyanoacrylate: Lumikit™ (Crime Scene Technology), were evaluated against a conventional two-step cyanoacrylate fuming method (Cyanobloom (Foster+Freeman Ltd.) with rhodamine 6G stain). The manufacturers' recommended conditions or conditions compatible with the MVC™ 1000/D (Foster+Freeman Ltd.) were assessed with fingermarks aged for up to 8 weeks on non-porous and semi-porous substrates. Under white light, Cyanobloom generally gave better development than the one-step treatments across the substrates. Similarly when viewed under the respective luminescent conditions, Cyanobloom with rhodamine 6G stain resulted in improved contrast against the one-step treatments except on polystyrene, where PolyCyano UV and PECA Multiband gave better visualisation. Rhodamine 6G post-treatment of one-step samples did not significantly enhance the contrast of any of the one-step treatments against Cyanobloom/rhodamine 6G-treated samples. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Luminescent Dinuclear Ruthenium Terpyridine Complexes with a Bis-Phenylbenzimidazole Spacer.

Science.gov (United States)

Mondal, Debiprasad; Biswas, Sourav; Paul, Animesh; Baitalik, Sujoy

2017-07-17

A conjugated bis-terpyridine bridging ligand, 2-(4-(2,6-di(pyridin-2-yl)pyridin-4-yl)phenyl)-6-(2-(4-(2,6-di(pyridin-2-yl)pyridin-4-yl)phenyl)-1H-benzo[d]imidazol-6-yl)-1H-benzo[d] imidazole (tpy-BPhBzimH 2 -tpy), was designed in this work by covalent coupling of 3,3'-diaminobenzidine and two 4'-(p-formylphenyl)-2,2':6',2″-terpyridine units to synthesize a new series of bimetallic Ru(II)-terpyridine light-harvesting complexes. Photophysical and electrochemical properties were modulated by the variation of the terminal ligands in the complexes. The new compounds were thoroughly characterized by 1 H NMR spectroscopy, high-resolution mass spectrometry, and elemental analysis. Absorption spectra of the complexes consist of very strong ligand-centered π-π* and n-π* transitions in the UV, metal-to-ligand, and intraligand charge transfer bands in the visible regions. Steady-state and time-resolved emission spectral measurements indicate that the complexes exhibit moderately intense luminescence at room temperature within the spectral domain of 653-687 nm having luminescence lifetimes in the range between 6.3 and 55.2 ns, depending upon terminal tridentate ligand and solvent. Variable-temperature luminescence measurements suggest substantial increase of the energy gap between luminescent 3 metal-to-ligand charge transfer state and nonluminescent 3 metal centered in the complexes compared to the parent [Ru(tpy) 2 ] 2+ . Each of the three bimetallic complexes exhibits only one reversible couple in the positive potential window with almost no detectable splitting corresponding to simultaneous oxidation of the two remote Ru centers. All the complexes possess a number of imidazole NH protons, which became sufficiently acidic upon metal ion coordination. By utilizing these NH protons, we thoroughly studied anion recognition properties of the complexes in pure organic as well as predominantly aqueous media through multiple optical channels and spectroscopic methods. Finally

Highly Water-Stable Lanthanide-Oxalate MOFs with Remarkable Proton Conductivity and Tunable Luminescence.

Science.gov (United States)

Zhang, Kun; Xie, Xiaoji; Li, Hongyu; Gao, Jiaxin; Nie, Li; Pan, Yue; Xie, Juan; Tian, Dan; Liu, Wenlong; Fan, Quli; Su, Haiquan; Huang, Ling; Huang, Wei

2017-09-01

Although proton conductors derived from metal-organic frameworks (MOFs) are highly anticipated for various applications including solid-state electrolytes, H 2 sensors, and ammonia synthesis, they are facing serious challenges such as poor water stability, fastidious working conditions, and low proton conductivity. Herein, we report two lanthanide-oxalate MOFs that are highly water stable, with so far the highest room-temperature proton conductivity (3.42 × 10 -3 S cm -1 ) under 100% relative humidity (RH) among lanthanide-based MOFs and, most importantly, luminescent. Moreover, the simultaneous response of both the proton conductivity and luminescence intensity to RH allows the linkage of proton conductivity with luminescence intensity. This way, the electric signal of proton conductivity variation versus RH will be readily translated to optical signal of luminescence intensity, which can be directly visualized by the naked eye. If proper lanthanide ions or even transition-metal ions are used, the working wavelengths of luminescence emissions can be further extended from visible to near infrared light for even wider-range applications. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Radiation-induced growth and isothermal decay of infrared-stimulated luminescence from feldspar

DEFF Research Database (Denmark)

Guralnik, Benny; Li, Bo; Jain, Mayank

2015-01-01

the growth and decay of laboratory-regenerated luminescence signals. Here we review a selection of common models describing the response of infrared stimulated luminescence (IRSL) of feldspar to constant radiation and temperature as administered in the laboratory. We use this opportunity to introduce...

Preparation, characterization, and luminescence properties of dysprosium perchlorate with MABA-Si and phen or dipy complexes as well as SiO{sub 2}@Dy(MABA-Si)L core-shell structure nanometermeter luminescent composites

Energy Technology Data Exchange (ETDEWEB)

Li, Wen-Xian, E-mail: nmglwx@163.com [College of Chemistry and Chemical Engineering, Inner Mongolia University, Hohhot 010021 (China); Zheng, Yu-Shan [Inner Mongolia Autonomous Region Product Quality Inspection Institute, Hohhot 010010 (China); Cao, Xiao-fang; Bai, Juan; Fu, Zhi-Fang; Bao, Jin-Rong; Li, Yi-Lian [College of Chemistry and Chemical Engineering, Inner Mongolia University, Hohhot 010021 (China)

2016-10-15

Two novel ternary rare earth complexes Dy(MABA-Si)·L{sub 2}(ClO{sub 4}){sub 3}·2H{sub 2}O (L= Phen or Dipy) were prepared using HOOCC{sub 6}H{sub 4}N(CONH(CH{sub 2}){sub 3}Si-(OCH{sub 2}CH{sub 3}){sub 3}){sub 2} which was abbreviated or denoted as MABA-Si. MABA-Si was the first ligand, L was the second ligand. The corresponding two SiO{sub 2}@Dy(MABA-Si)L nanometermeter luminescent composites were synthesized as well, and the silica spheres is the core, and the ternary rare earth complex Dy(MABA-Si)·L{sub 2}(ClO{sub 4}){sub 3}·2H{sub 2}O was the shell layer, who was abbreviated or denoted as Dy((MABA-Si)L). The ternary complexes have been characterized by element analysis, molar conductivity, IR spectra and {sup 1}HNMR spectra. The results showed that the chemical formula of the complex was Dy(MABA-Si)·L{sub 2}(ClO{sub 4}){sub 3}·2H{sub 2}O. The fluorescent spectra illustrated that the complexes displayed its characteristic luminescence in solid state, and the luminescence was superior than Dy{sup 3+}. The core-shell structure of SiO{sub 2}@Dy(MABA-Si)L nanometermeter luminescent composite was characterized by SEM, TEM and IR spectra. Based on the SEM photographs, the core-shell structure particles showed its regular microstructure including smooth surface, and good dispersity. The ternary complex coated on the mono-dispersed SiO{sub 2} spheres by self-assembly. The fluorescent spectra illustrated that the core-shell structure of SiO{sub 2}@Dy(MABA-Si)L nanometermeter luminescent composites exhibited stronger fluorescent than the ternary complexes. The fluorescence lifetime of the complexes and core-shell structure composites was measured as well.

Kinetic study of Tb/sup 3 +/(/sup 5/D/sub 3/) luminescence in phosphate glasses

Energy Technology Data Exchange (ETDEWEB)

Anisimov, V.A.; Dmitryuk, A.V.; Karapetyan, G.O.

1986-01-01

This paper presents precise determinations of the kinetics of terbium luminescence over a broad dynamic range, in order to refine the mechanism of concentration quenching of the Tb/sup 3 +/(/sup 5/D/sub 3/) luminescence in glasses. After establishing the mechanism of Tb/sup 3 +/(/sup 5/D/sub 3/) luminescence quenching by the iteration method, the authors determine the value of the parameter for an arbitrary concentration of the activator. Results of this study show that the mechanism of concentration quenching of luminescence is static dipole-dipole interaction of terbium ions.

First Release of Gravimetric Geoid Model over Saudi Arabia Based on Terrestrial Gravity and GOCE Satellite Data: KSAG01

Science.gov (United States)

Alothman, Abdulaziz; Elsaka, Basem

2016-04-01

A new gravimetric quasi-geoid, known as KSAG0, has been developed recently by Remove-Compute-Restore techniques (RCR), provided by the GRAVSOFT software, using gravimetric free air anomalies. The terrestrial gravity data used in this computations are: 1145 gravity field anomalies observed by ARAMCO (Saudi Arabian Oil Company) and 2470 Gravity measurements from BGI (Bureau Gravimétrique International). The computations were carried out implementing the least squares collocation method through the RCR techniques. The KSAG01 is based on merging in addition to the terrestrial gravity observations, GOCE satellite model (Eigen-6C4) and global gravity model (EGM2008) have been utilized in the computations. The long, medium and short wavelength spectrum of the height anomalies were compensated from Eigen-6C4 and EGM2008 geoid models truncated up to Degree and order (d/o) up to 2190. KSAG01 geoid covers 100 per cent of the kingdom, with geoid heights range from - 37.513 m in the southeast to 23.183 m in the northwest of the country. The accuracy of the geoid is governed by the accuracy, distribution, and spacing of the observations. The standard deviation of the predicted geoid heights is 0.115 m, with maximum errors of about 0.612 m. The RMS of geoid noise ranges from 0.019 m to 0.04 m. Comparison of the predicted gravimetric geoid with EGM, GOCE, and GPS/Levelling geoids, reveals a considerable improvements of the quasi-geoid heights over Saudi Arabia.

A series of new Eu/Tb mixed MOFs with tunable color luminescence

Energy Technology Data Exchange (ETDEWEB)

Luo, Ximing; He, Xingxiang; Shi, Jie; Cui, Chenhui; Xu, Yan [College of Chemistry and Chemical Engineering, State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing (China)

2018-01-17

Two isostructural lanthanide metal-organic frameworks [Ln-MOFs, Ln = Tb (1), Eu (8)] containing oxalic acid ligand with green, red luminescence were solvothermally synthesized. A series of Eu/Tb mixed MOFs (2-7), (C{sub 5}H{sub 6}N){sub 2}[Eu{sub x}Tb{sub 2-x}(H{sub 2}O){sub 2}(C{sub 2}O{sub 4}){sub 4}].2H{sub 2}O, were designed and obtained, which displayed highly tunable luminescence color by adjusting the excitation wavelength. Complexes 1-8 were characterized by IR, elemental analysis, ICP, powder XRD, and TG measurements. The quantum yields of the complexes 1-8 range from 6.89 to 4.15 %, whereas the fluorescence lifetime of 1-8 varies between 1.12 and 0.87 ms. Therefore, with the increase of the molar ratio of Eu, the quantum yields and fluorescence lifetime of the complexes 1-8 gradually decrease. (copyright 2018 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Development of a ratiometric time-resolved luminescence sensor for pH based on lanthanide complexes.

Science.gov (United States)

Liu, Mingjing; Ye, Zhiqiang; Xin, Chenglong; Yuan, Jingli

2013-01-25

Time-resolved luminescence bioassay technique using lanthanide complexes as luminescent probes/sensors has shown great utilities in clinical diagnostics and biotechnology discoveries. In this work, a novel terpyridine polyacid derivative that can form highly stable complexes with lanthanide ions in aqueous media, (4'-hydroxy-2,2':6',2''-terpyridine-6,6''-diyl) bis(methylenenitrilo) tetrakis(acetic acid) (HTTA), was designed and synthesized for developing time-resolved luminescence pH sensors based on its Eu(3+) and Tb(3+) complexes. The luminescence characterization results reveal that the luminescence intensity of HTTA-Eu(3+) is strongly dependent on the pH values in weakly acidic to neutral media (pK(a) = 5.8, pH 4.8-7.5), while that of HTTA-Tb(3+) is pH-independent. This unique luminescence response allows the mixture of HTTA-Eu(3+) and HTTA-Tb(3+) (the HTTA-Eu(3+)/Tb(3+) mixture) to be used as a ratiometric luminescence sensor for the time-resolved luminescence detection of pH with the intensity ratio of its Tb(3+) emission at 540 nm to its Eu(3+) emission at 610 nm, I(540 nm)/I(610 nm), as a signal. Moreover, the UV absorption spectrum changes of the HTTA-Eu(3+)/Tb(3+) mixture at different pHs (pH 4.0-7.0) also display a ratiometric response to the pH changes with the ratio of absorbance at 290 nm to that at 325 nm, A(290 nm)/A(325 nm), as a signal. This feature enables the HTTA-Eu(3+)/Tb(3+) mixture to have an additional function for the pH detection with the absorption spectrometry technique. For loading the complexes into the living cells, the acetoxymethyl ester of HTTA was synthesized and used for loading HTTA-Eu(3+) and HTTA-Tb(3+) into the cultured HeLa cells. The luminescence imaging results demonstrated the practical utility of the new sensor for the time-resolved luminescence cell imaging application. Copyright © 2012 Elsevier B.V. All rights reserved.

Bistable luminescence of trivalent rare-earth ions in crystals

International Nuclear Information System (INIS)

Sole, Jose Garcia; Ramirez O, Maria de la; Rodenas, Airan; Jaque, Daniel; Bausa, Luisa; Bettinelli, Marco; Speghini, Adolfo; Cavalli, Enrico; Ivleva, Lioudmila

2006-01-01

In this work, we have examined three new bistable systems based on the luminescence of three different crystals activated with trivalent rare earth ions. We have focussed our attention on Yb 3+ ions activators, for which the most relevant results are obtained. The first crystal, Sr 0.6 Ba 0.4 Nb 2 O 6 , is a ferroelectric material with a relatively low phase transition temperature (∼370 K), which provides bistability in the luminescence of Yb 3+ ions due to the thermal hysteresis associated with phase transition. The second crystal, LiNbO 3 , provides an intrinsic bistability in the luminescence of Yb 3+ ions, which is driven by changes in the excitation intensity. In the third crystal, NdPO 4 , a new mechanism of excitation intensity driven bistability is obtained when activated with Yb 3+ ions, due to a interplay between the Nd 3+ ↔Yb 3+ energy transfer and back transfer processes

Identification of yellow luminescence centers in Be-doped GaN through pressure-dependent studies

Science.gov (United States)