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Sample records for strong nir luminescence

  1. Dual mode NIR long persistent phosphorescence and NIR-to-NIR Stokes luminescence in La{sub 3}Ga{sub 5}GeO{sub 14}: Cr{sup 3+}, Nd{sup 3+} phosphor

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Yiling; Li, Yang, E-mail: msliyang@scut.edu.cn; Qin, Xixi; Chen, Ruchun; Wu, Dakun; Liu, Shijian; Qiu, Jianrong, E-mail: qjr@scut.edu.cn

    2015-11-15

    Recently, long persistent phosphors (LPPs) have been considered to be the most prominent candidates for biomedical applications. However, the LPPs suffer from a dramatic decrease in luminescence intensity after incorporation into the tissue. Therefore, it is very necessary to develop the more competitive LPPs and acquire the reproducible tissue imaging. Here, we propose and experimentally demonstrate an effective bifunctional La{sub 3}Ga{sub 5}GeO{sub 14}: Cr{sup 3+}, Nd{sup 3+} phosphor with the interesting characteristic of near-infrared long persistent phosphorescence and NIR-to-NIR Stokes luminescence. Cr{sup 3+} and Nd{sup 3+} ions are simultaneously selected as the emission centers in order to take advantage of the remarkable phosphorescence properties of Cr{sup 3+}, and the appropriate energy level characteristic of NIR-excitation band (808 nm) and NIR-emission (1064 nm), and the ability as the brilliant auxiliary to create more efficient defects of Nd{sup 3+}. The efficient dual-modal emission is, accordingly utilized to realize the convenient, high-resolution global detection and local imaging. - Highlights: • Dual mode phosphor with NIR long afterglow and NIR-to-NIR Stokes luminescence. • Increasing the persistent duration due to the codoping of Nd. • Avoiding the noteworthy overheating effect due to the strong absorption at 980 nm.

  2. Grassy Silica Nanoribbons and Strong Blue Luminescence

    Science.gov (United States)

    Wang, Shengping; Xie, Shuang; Huang, Guowei; Guo, Hongxuan; Cho, Yujin; Chen, Jun; Fujita, Daisuke; Xu, Mingsheng

    2016-09-01

    Silicon dioxide (SiO2) is one of the key materials in many modern technological applications such as in metal oxide semiconductor transistors, photovoltaic solar cells, pollution removal, and biomedicine. We report the accidental discovery of free-standing grassy silica nanoribbons directly grown on SiO2/Si platform which is commonly used for field-effect transistors fabrication without other precursor. We investigate the formation mechanism of this novel silica nanostructure that has not been previously documented. The silica nanoribbons are flexible and can be manipulated by electron-beam. The silica nanoribbons exhibit strong blue emission at about 467 nm, together with UV and red emissions as investigated by cathodoluminescence technique. The origins of the luminescence are attributed to various defects in the silica nanoribbons; and the intensity change of the blue emission and green emission at about 550 nm is discussed in the frame of the defect density. Our study may lead to rational design of the new silica-based materials for a wide range of applications.

  3. Transparent CuInS2/PMMA nanocomposites luminescent in the visible and NIR region

    International Nuclear Information System (INIS)

    Gugula, Krzysztof; Bredol, Michael

    2014-01-01

    Nanocomposites combining functional nanoparticles and transparent polymers allow for stabilization of filler properties over long periods of time while retaining transparency of the polymer matrix. Here we employ CuInS 2 /ZnS quantum dots (QDs), ternary visible- and NIR-emitting semiconductors as wavelength-tunable luminescent fillers. Luminescence in the near infrared (NIR) is of particular interest in medicine which allows deep penetration into human tissue enabling in vivo diagnostics and treatment, while visible emitters may serve as color converters in displays or lighting. To stabilize the optical properties of QDs and prevent agglomeration, polymethyl metacrylate (PMMA) was chosen as a matrix. These novel polymer nanocomposites (PNCs) show good optical properties and stability under ambient conditions, and can be easily deposited over large areas. High-quality QDs and hydrophobic functionalization with long-chain hydrocarbons are a prerequisite for embedding into a PMMA matrix. Transparent PNC films without visible scattering losses were obtained for 1 wt-% QD loading with respect to the polymer. Partial transparency is retained up to 10 wt-% QD loading and vanishes rapidly at higher loading. Luminescence properties increase up to 5 wt-% and then decrease rapidly due to QD agglomeration and reabsorption between adjacent particles. Potential applications include converter materials for medical applications, laser layers, displays and white LEDs. (orig.)

  4. Visible and NIR luminescence of nanocrystalline β-Ga2O3:Er3+ prepared by solution combustion synthesis

    International Nuclear Information System (INIS)

    Biljan, Tomislav; Gajovic, Andreja; Meic, Zlatko

    2008-01-01

    In this paper we report on facile solution combustion synthesis of erbium doped β-Ga 2 O 3 with urea as fuel. The product 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 of β-Ga 2 O 3 :Er are studied with excitation in near infrared (Nd:YAG laser at 1064 nm) and visible (argon laser at 514.5 nm). A strong NIR emission of Er 3+ in the window of minimal optical loss in silica based optical fibers, due to the 4 I 13/2 → 4 I 15/2 transition at 1.55 μm has been observed. Codoping with Yb 3+ significantly increases the intensity of that important emission

  5. Heterogeneously Nd3+ doped single nanoparticles for NIR-induced heat conversion, luminescence, and thermometry.

    Science.gov (United States)

    Marciniak, Lukasz; Pilch, Aleksandra; Arabasz, Sebastian; Jin, Dayong; Bednarkiewicz, Artur

    2017-06-22

    The current frontier in nanomaterials engineering is to intentionally design and fabricate heterogeneous nanoparticles with desirable morphology and composition, and to integrate multiple functionalities through highly controlled epitaxial growth. Here we show that heterogeneous doping of Nd 3+ ions following a core-shell design already allows three optical functions, namely efficient (η > 72%) light-to-heat conversion, bright NIR emission, and sensitive (S R > 0.1% K -1 ) localized temperature quantification, to be built within a single ca. 25 nm nanoparticle. Importantly, all these optical functions operate within the transparent biological window of the NIR spectral region (λ exc ∼ 800 nm, λ emi ∼ 860 nm), in which light scattering and absorption by tissues and water are minimal. We find NaNdF 4 as a core is efficient in absorbing and converting 808 nm light to heat, while NaYF 4 :1%Nd 3+ as a shell is a temperature sensor based on the ratio-metric luminescence reading but an intermediate inert spacer shell, e.g. NaYF 4 , is necessary to insulate the heat convertor and thermometer by preventing the possible Nd-Nd energy relaxation. Moreover, we notice that while temperature sensitivity and luminescence intensity are optically stable, increased excitation intensity to generate heat above room temperature may saturate the sensing capacity of temperature feedback. We therefore propose a dual beam photoexcitation scheme as a solution for possible light-induced hyperthermia treatment.

  6. Enhanced performance of dye-sensitized solar cells based on TiO{sub 2} with NIR-absorption and visible upconversion luminescence

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Li [Department of Chemistry, Harbin Institute of Technology, Harbin 150001 (China); Yulin, Yang, E-mail: ylyang@hit.edu.cn [Department of Chemistry, Harbin Institute of Technology, Harbin 150001 (China); Mi, Zhou; Ruiqing, Fan; LeLe, Qiu [Department of Chemistry, Harbin Institute of Technology, Harbin 150001 (China); Xin, Wang [Department of Chemistry, Harbin Institute of Technology, Harbin 150001 (China); Department of Food and Environmental Engineering, Heilongjiang, East University, Harbin 150086 (China); Lingyun, Zhang [Department of Chemistry, Harbin Institute of Technology, Harbin 150001 (China); School of Chemical Engineering, Northeast Dianli University, Jilin 132012 (China); Xuesong, Zhou; Jianglong, He [Department of Chemistry, Harbin Institute of Technology, Harbin 150001 (China)

    2013-02-15

    TiO{sub 2} with NIR-absorption and visible upconversion luminescence (UC-TiO{sub 2}) is prepared by a sol-gel method and calcined at 700 Degree-Sign C for 6 h. The material broadens the response region of dye sensitized solar cells (DSSCs) from an ultraviolet-visible region to the whole region of the solar spectrum. It shifts NIR sunlight to visible light which matches the strong absorbing region of the dye (N719). DSSCs based on UC-TiO{sub 2} achieved higher conversion efficiency than that on raw TiO{sub 2}. UC-TiO{sub 2} was mixed with commercial raw TiO{sub 2} as additive, and the short-circuit current density, open-circuit voltage and conversion efficiency of the DSSC reached to the optimum values 13.38 mA/cm{sup 2}, 0.78 V and 6.63% (AM1.5 global), comparing with the blank values: 7.99 mA/cm{sup 2}, 0.75 V and 4.07%, respectively. Also the mechanisms of upconversion by multiphoton absorption and energy transfer processes are interpreted in this paper. - Graphical abstract: By introducing TiO{sub 2} with NIR-absorption and visible up-conversion luminescence into DSSC, a signal reflection was explored from ultra-violet region to visible region, and to near-IR region. Highlights: Black-Right-Pointing-Pointer TiO{sub 2} with NIR-absorption and visible up-conversion luminescence (UC-TiO{sub 2}) was prepared by a sol-gel method. Black-Right-Pointing-Pointer A systematic characterization and analysis was carried out to discuss the mechanism. Black-Right-Pointing-Pointer A significantly enhanced performance of DSSC was explored by using UC-TiO{sub 2} as an additive.

  7. NIR Ratiometric Luminescence Detection of pH Fluctuation in Living Cells with Hemicyanine Derivative-Assembled Upconversion Nanophosphors.

    Science.gov (United States)

    Li, Haixia; Dong, Hao; Yu, Mingming; Liu, Chunxia; Li, Zhanxian; Wei, Liuhe; Sun, Ling-Dong; Zhang, Hongyan

    2017-09-05

    It is crucial for cell physiology to keep the homeostasis of pH, and it is highly demanded yet challenging to develop luminescence resonance energy transfer (LRET)-based near-infrared (NIR) ratiometric luminescent sensor for the detection of pH fluctuation with NIR excitation. As promising energy donors for LRET, upconversion nanoparticles (UCNPs) have been widely used to fabricate nanosensors, but the relatively low LRET efficiency limits their application in bioassay. To improve the LRET efficiency, core/shell/shell structured β-NaGdF 4 @NaYF 4 :Yb,Tm@NaYF 4 UCNPs were prepared and decorated with hemicyanine dyes as an LRET-based NIR ratiometric luminescent pH fluctuation-nanosensor for the first time. The as-developed nanosensor not only exhibits good antidisturbance ability, but it also can reversibly sense pH and linearly sense pH in a range of 6.0-9.0 and 6.8-9.0 from absorption and upconversion emission spectra, respectively. In addition, the nanosensor displays low dark toxicity under physiological temperature, indicating good biocompatibility. Furthermore, live cell imaging results revealed that the sensor can selectively monitor pH fluctuation via ratiometric upconversion luminescence behavior.

  8. Detection - NIR, Luminescence and Other Rapid Methods-Pit Falls and Opportunities

    International Nuclear Information System (INIS)

    Trudil, D.

    2007-01-01

    The proliferation of rapid, on-site biological detectors over the last 15 years has caused confusion within the user community and in some cases a diversion of resources. There remains no panacea; all systems have issues and no system provides the total answer. In 1995, with much enthusiasm, members of a US National Lab presented a mock-up of a hand held Biological Detector. This system, compared to a 'Tricorder' from science fiction, was envisioned to be available within 5 years. It would be able to scan a substance and within minutes provide an answer. Clearly that remains the goal of detector programs, but unfortunately science is the limiting factor. There are technologies, such as fluorescence and luminescence that provide minimally acceptable results when utilizing a defined bio-air sample. Many of these systems are also expensive, limiting their utility. But when these FLAPS, BARTS, BAWS, BioLerts and other are challenged with dirty or non-aerosol samples, they begin to have problems. With the relatively high cost of test kits, the significant number of potential hoax or negative samples; the issue of usefulness versus performance versus cost has further complicated the environment. Consequently, the utilization of cost effective, simple screening systems is needed for on site use. The current trend is to determine cost effective approaches to triage samples prior to in depth analysis. Therefore, a pH test, protein strip and Bioluminescence screen can indicate threat/non-threat prior to in-depth analysis. Experiences from 2001/2002 indicate over 90% of the first responder events are hoax related. Adapting the paradigm, screening out negatives become a priority. Near Infra Red (NIR) has been utilized in chemical agent detection and has been recently utilized to identify powders, salts, sugars and numerous potential hoax samples. The system is a non-destructive screening method that can be integrated with other technologies as a front end triage system

  9. Efficient NIR (near-infrared) luminescent ZnLn-grafted (Ln=Nd, Yb or Er) PNBE (Poly(norbornene))

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Lin; Feng, Hei-Ni; Fu, Guo-Rui; Li, Bao-Ning [School of Chemical Engineering, Shaanxi Key Laboratory of Degradable Medical Material, Northwest University, Xi’an 710069, Shaanxi (China); Lü, Xing-Qiang, E-mail: lvxq@nwu.edu.cn [School of Chemical Engineering, Shaanxi Key Laboratory of Degradable Medical Material, Northwest University, Xi’an 710069, Shaanxi (China); Wong, Wai-Kwok [Department of Chemistry, Hong Kong Baptist University, Waterloo Road, Kowloon Tong, Hong Kong (China); Jones, Richard A. [Department of Chemistry and Biochemistry, The University of Texas at Austin, 1 University Station A5300, Austin, TX 78712-0165 (United States)

    2017-06-15

    Through the ring-opening metathesis polymerization (ROMP) of norbornene (NBE) with each of allyl-containing complex monomers [Zn(L){sub 2}(µ{sub 1}-OAc)Ln(µ{sub 2}-OAc){sub 2}] (Ln=La, 1; Nd, 2; Yb, 3; Er, 4 or Gd, 5; HL=4-allyl-2-(1H-benzo[d]imidazol-2-yl)-6-methoxyphenol), a series of ZnLn-grafted polymers Poly([Zn(L){sub 2}(µ{sub 1}-OAc)Ln(µ{sub 2}-OAc){sub 2}]-co-NBE) with desired physical properties were obtained, respectively. Within near-infrared (NIR) luminescent polymers, Poly(3-co-NBE) endows an attractive quantum yield of 1.47% in solid state, and exhibits an effective prevention of high-concentration self-quenching. - Graphical abstract: Through grafting of [Zn(L){sub 2}(µ{sub 1}-OAc)Ln(µ{sub 2}-OAc){sub 2}] (Ln=Nd, 2; Yb, 3 or Er, 4) into PNBE with desired physical properties including NIR luminescence, Poly(3-co-NBE) exhibits an attractive quantum yield of 1.47% and an effective emitters' clustering prevention.

  10. NIR dual luminescence from an extended porphyrin. Spectroscopy, photophysics and theory.

    Science.gov (United States)

    Gourlaouen, Christophe; Daniel, Chantal; Durola, Fabien; Frey, Julien; Heitz, Valérie; Sauvage, Jean-Pierre; Ventura, Barbara; Flamigni, Lucia

    2014-05-22

    Spectroscopic and photophysical properties of an extended Zn porphyrin with fused bis(tetraazaanthracene) arms including a 2,9-diphenyl-1,10-phenanthroline incorporated in a polyether macrocycle are investigated in solvents of different polarity pointing to the presence of two emitting singlet excited states. The absorption and emission features are identified and ascribed, on the basis of solvent polarity dependence, to a π-π* and to a charge transfer (CT) state, respectively. Whereas the intraligand π-π* transition is assigned to the intense absorption observed at 442-455 nm, the CT states contribute to the bands at 521-525 nm and 472-481 nm. The theoretical analysis of the absorption spectrum confirms the presence of two strong bands centered at 536 and 437 nm corresponding to CT and π-π* states, respectively. Weak CT transitions are calculated at 657 and 486 nm. Two emission maxima are observed in toluene at 724 nm from a (1)π-π* state and at 800 nm from a (1)CT state, respectively. (1)CT bands shift bathochromically by increasing the solvent polarity whereas the energy of the (1)π-π band is less affected. Likewise, the emission yield and lifetime associated with the low energy (1)CT band are strongly affected by solvent polarity. This is rationalized by a (1)π-π* → (1)CT internal conversion driven by solvent polarity, this process being competitive with the (1)π-π* to ground state deactivation channel. Time resolved absorption spectra indicate the presence of two triplet states, a short-lived one (nanoseconds range) and a longer lived one (hundreds of microsecond range) ascribed to a (3)π-π* and a (3)CT, respectively. For them, a conversion mechanism similar to that of the singlet excited states is suggested.

  11. Two-step excitation structure changes of luminescence centers and strong tunable blue emission on surface of silica nanospheres

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Lei, E-mail: nanoyang@qq.com; Jiang, Zhongcheng; Dong, Jiazhang; Zhang, Liuqian [Hunan University, College of Materials Science and Engineering (China); Pan, Anlian, E-mail: anlian.pan@gmail.com; Zhuang, Xiujuan [Hunan University, Key Laboratory for Micro-Nano Physics and Technology of Hunan Province (China)

    2015-10-15

    We report a scheme for investigating two-step stimulated structure change of luminescence centers. Amorphous silica nanospheres with uniform diameter of 9–15 nm have been synthesized by Stöber method. Strong hydroxyl-related infrared-absorption band is observed in infrared spectrum. The surface hydroxyl groups exert great influence on the luminescent behavior of silica. They provide stable and intermediate energy states to accommodate excitation electrons. The existence of these surface states reduces the energy barrier of photochemical reactions, creating conditions for two-step excitation process. By carefully examining excitation and emission process, the nearest excitation band is absent in both optical absorption spectrum and excitation spectrum. This later generated state confirms the generation of new luminescence centers as well as the existence of photochemical reactions. Stimulated by different energies, two-step excitation process impels different photochemical reactions, prompting generation of different lattice defects on surface area of silica. Thereby, tunable luminescence is achieved. After thermal treatment, strong gap excitation band appears with the disappearance of strong surface excitation band. Strong blue luminescence also disappears. The research is significance to precise introducing structural defects and controlling position of luminescence peaks.

  12. Strongly luminescent monolayered MoS2 prepared by effective ultrasound exfoliation.

    Science.gov (United States)

    Štengl, Václav; Henych, Jiří

    2013-04-21

    Intense ultrasound in a pressurized batch reactor was used for preparation of monolayered MoS2 nanosheets from natural mineral molybdenite. Exfoliation of bulk MoS2 using ultrasound is an attractive route to large-scale preparation of monolayered crystals. To evaluate the quality of delamination, methods like X-ray diffraction, Raman spectroscopy and microscopic techniques (TEM and AFM) were employed. From single- or few-layered products obtained from intense sonication, MoS2 quantum dots (MoSQDs) were prepared by a one-pot reaction by refluxing exfoliated nanosheets of MoS2 in ethylene glycol under atmospheric pressure. The synthesised MoSQDs were characterised by photoluminescence spectroscopy and laser-scattering particle size analysis. Our easy preparation leads to very strongly green luminescing quantum dots.

  13. Efficient and selective singlet oxygen sensitized NIR luminescence of a neodymium(III) complex and its application in biological imaging

    Energy Technology Data Exchange (ETDEWEB)

    Lo, Wai-Sum [Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hong Kong Special Administrative Region (Hong Kong); Li, Hongguang [Department of Chemistry, Hong Kong Baptist University, Kowloon Tong, Hong Kong Special Administrative Region (Hong Kong); Law, Ga-Lai, E-mail: ga-lai.law@polyu.edu.hk [Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hong Kong Special Administrative Region (Hong Kong); Wong, Wing-Tak, E-mail: bcwtwong@polyu.edu.hk [Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hong Kong Special Administrative Region (Hong Kong); Wong, Ka-Leung, E-mail: klwong@hkbu.edu.hk [Department of Chemistry, Hong Kong Baptist University, Kowloon Tong, Hong Kong Special Administrative Region (Hong Kong)

    2016-01-15

    A responsive neodymium NIR emission ({sup 4}F{sub 3/2}→{sup 4}I{sub 11/2,} {sub 9/2}) was recorded upon binding with singlet oxygen (K{sub B}=1.79×10{sup 6} M{sup −1}) via the anthracene moiety. The motif ytterbium analog served as a negative control with no significant NIR enhancement/quenching with the addition of the same amount of singlet oxygen. Our complex was also found to react with {sup 1}O{sub 2} generated by a known photosensitizer TMPyP inside HeLa cells without inducing cell death and display no significant cytotoxicity. - Highlights: • A turn-on NIR-emissive {sup 1}O{sub 2} probe has been synthesized for potential biological applications. • It has a binding constant of 1.9×10{sup 6} M{sup −1} and the emission intensity has a 5-fold increase upon binding. • The probe was also found to quench singlet oxygen in vitro generated by known photosensitizer TMPyP.

  14. NIR to VIS frequency upconversion luminescence properties of Er{sup 3+}-doped YPO{sub 4} phosphors

    Energy Technology Data Exchange (ETDEWEB)

    Balakrishnaiah, R. [Department of Electronic Materials Engineering, Silla University, Busan 617-736 (Korea, Republic of); Department of Physics, Pukyong National University, Busan 608-737 (Korea, Republic of); Kim, Dong Woo [Department of Electronic Materials Engineering, Silla University, Busan 617-736 (Korea, Republic of); Yi, Soung Soo, E-mail: ssyi@silla.ac.k [Department of Electronic Materials Engineering, Silla University, Busan 617-736 (Korea, Republic of); Kim, Sung Hoon [Department of Engineering in Energy and Applied Chemistry, Silla University, Busan 617-736 (Korea, Republic of); Jang, Kiwan; Lee, Ho Sueb [Department of Physics, Changwon National University, Changwon 641-773 (Korea, Republic of); Moon, Byung Kee; Jeong, Jung Hyun [Department of Physics, Pukyong National University, Busan 608-737 (Korea, Republic of)

    2010-09-01

    Different concentrations of Er{sup 3+}-doped YPO{sub 4}:Er powder phosphors have been synthesized by the conventional solid state reaction method and are characterized by X-ray diffraction (XRD), field emission scanning electronic microscopy (FESEM), and upconversion emission measurements. An intense red emission band and a weak green emission band are observed under NIR excitation at 975 nm in case of samples with high dopant concentration while no upconversion emission was observed at lower Er{sup 3+} ion concentrations. The possible mechanisms involved in the upconversion process have been discussed in comparison to results with similar reported works.

  15. Bifunctional Zn(II)Ln(III) dinuclear complexes combining field induced SMM behavior and luminescence: enhanced NIR lanthanide emission by 9-anthracene carboxylate bridging ligands.

    Science.gov (United States)

    Palacios, María A; Titos-Padilla, Silvia; Ruiz, José; Herrera, Juan Manuel; Pope, Simon J A; Brechin, Euan K; Colacio, Enrique

    2014-02-03

    There were new dinuclear Zn(II)-Ln(III) complexes of general formulas [Zn(μ-L)(μ-OAc)Ln(NO3)2] (Ln(III) = Tb (1), Dy (2), Er (3), and Yb (4)), [Zn(μ-L)(μ-NO3)Er(NO3)2] (5), [Zn(H2O)(μ-L)Nd(NO3)3]·2CH3OH (6), [Zn(μ-L)(μ-9-An)Ln(NO3)2]·2CH3CN (Ln(III) = Tb (7), Dy (8), Er (9), Yb(10)), [Zn(μ-L)(μ-9-An)Yb(9-An)(NO3)3]·3CH3CN (11), [Zn(μ-L)(μ-9-An)Nd(9-An)(NO3)3]·2CH3CN·3H2O (12), and [Zn(μ-L)(μ-9-An)Nd(CH3OH)2(NO3)]ClO4·2CH3OH (13) prepared from the reaction of the compartmental ligand N,N',N″-trimethyl-N,N″-bis(2-hydroxy-3-methoxy-5-methylbenzyl)diethylenetriamine (H2L), with ZnX2·nH2O (X = NO3(-) or OAc(-)) salts, Ln(NO3)3·nH2O, and, in some instances, 9-anthracenecarboxylate anion (9-An). In all these complexes, the Zn(II) ions invariably occupy the internal N3O2 site whereas the Ln(III) ions show preference for the O4 external site, giving rise to a Zn(μ-diphenoxo)Ln bridging fragment. Depending on the Zn(II) salt and solvent used in the reaction, a third bridge can connect the Zn(II) and Ln(III) metal ions, giving rise to triple-bridged diphenoxoacetate in complexes 1-4, diphenoxonitrate in complex 5, and diphenoxo(9-anthracenecarboxylate) in complexes 8-13. Dy(III) and Er(III) complexes 2, 8 and 3, 5, respectively, exhibit field induced single molecule magnet (SMM) behavior, with Ueff values ranging from 11.7 (3) to 41(2) K. Additionally, the solid-state photophysical properties of these complexes are presented showing that ligand L(2-) is able to sensitize Tb(III)- and Dy(III)-based luminescence in the visible region through an energy transfer process (antenna effect). The efficiency of this process is much lower when NIR emitters such as Er(III), Nd(III), and Yb(III) are considered. When the luminophore 9-anthracene carboxylate is incorporated into these complexes, the NIR luminescence is enhanced which proves the efficiency of this bridging ligand to act as antenna group. Complexes 2, 3, 5, and 8 can be considered as dual materials

  16. NIR luminescent Er{sup 3+}/Yb{sup 3+} co-doped SiO{sub 2}-ZrO{sub 2} nanostructured planar and channel waveguides: Optical and structural properties

    Energy Technology Data Exchange (ETDEWEB)

    Cunha, Cesar dos Santos [Departamento de Quimica, Faculdade de Filosofia, Ciencias e Letras de Ribeirao Preto, Universidade de Sao Paulo, Av. Bandeirantes, 3900, 14040-901, Ribeirao Preto/SP (Brazil); Ferrari, Jefferson Luis [Grupo de Pesquisa em Quimica de Materiais - (GPQM), Departamento de Ciencias Naturais, Universidade Federal de Sao Joao Del Rei, Campus Dom Bosco, Praca Dom Helvecio, 74, 36301-160, Sao Joao Del Rei, MG (Brazil); Oliveira, Drielly Cristina de [Departamento de Quimica, Faculdade de Filosofia, Ciencias e Letras de Ribeirao Preto, Universidade de Sao Paulo, Av. Bandeirantes, 3900, 14040-901, Ribeirao Preto/SP (Brazil); Maia, Lauro June Queiroz [Grupo Fisica de Materiais, Instituto de Fisica, UFG, Campus Samambaia, Caixa Postal 131, 74001-970, Goiania/GO (Brazil); Gomes, Anderson Stevens Leonidas [Departamento de Fisica, Universidade Federal de Pernambuco, Cidade Universitaria, Recife/PE, 50670-901 (Brazil); Ribeiro, Sidney Jose Lima [Laboratorio de Materiais Fotonicos, Instituto de Quimica, UNESP, Caixa Postal 355, 14801-970, Araraquara/SP (Brazil); and others

    2012-09-14

    Optical and structural properties of planar and channel waveguides based on sol-gel Er{sup 3+} and Yb{sup 3+} co-doped SiO{sub 2}-ZrO{sub 2} are reported. Microstructured channels with high homogeneous surface profile were written onto the surface of multilayered densified films deposited on SiO{sub 2}/Si substrates by a femtosecond laser etching technique. The densification of the planar waveguides was evaluated from changes in the refractive index and thickness, with full densification being achieved at 900 Degree-Sign C after annealing from 23 up to 500 min, depending on the ZrO{sub 2} content. Crystal nucleation and growth took place together with densification, thereby producing transparent glass ceramic planar waveguides containing rare earth-doped ZrO{sub 2} nanocrystals dispersed in a silica-based glassy host. Low roughness and crack-free surface as well as high confinement coefficient were achieved for all the compositions. Enhanced NIR luminescence of the Er{sup 3+} ions was observed for the Yb{sup 3+}-codoped planar waveguides, denoting an efficient energy transfer from the Yb{sup 3+} to the Er{sup 3+} ion. Highlights: Black-Right-Pointing-Pointer Sol-gel high NIR luminescent nanostructured planar and channel waveguides. Black-Right-Pointing-Pointer Microstructured channels written by a femtosecond laser etching technique. Black-Right-Pointing-Pointer Transparent glass ceramic with rare earth-doped ZrO{sub 2} nanocrystals in a silica host. Black-Right-Pointing-Pointer Enhanced NIR luminescence, efficient energy transfer from the Yb{sup 3+} to the Er{sup 3+} ion. Black-Right-Pointing-Pointer New planar channel waveguides to be applied as EDWA in the C telecommunication band.

  17. Strongly luminescent InP/ZnS core-shell nanoparticles.

    Science.gov (United States)

    Haubold, S; Haase, M; Kornowski, A; Weller, H

    2001-05-18

    The wide-bandgap semiconducting material, zinc sulfide, has been coated on indium phosphide nanoclusters to a 1-2-Å thickness. The resulting InP-ZnS core-shell particle (as shown in the TEM image; scale 1 cm=5 nm) exhibits bright luminescence at room temperature with quantum efficiencies as high as 23 %. © 2001 WILEY-VCH Verlag GmbH, Weinheim, Fed. Rep. of Germany.

  18. Strongly Enhanced Free-Exciton Luminescence in Microcrystalline CsPbBr3 Films

    Science.gov (United States)

    Kondo, Shin-ichi; Kakuchi, Mitsugu; Masaki, Atsushi; Saito, Tadaaki

    2003-07-01

    The luminescence properties of CsPbBr3 films prepared via the amorphous phase by crystallization are dominated by free-exciton emission, and only a weak trace of emission due to trapped excitons was observed, in contrast to the case of bulk CsPbBr3 crystals. In particular, the films in the microcrystalline state show by more than an order of magnitude stronger free-exciton emission than in the polycrystalline state. The enhanced free-exciton emission is suggestive of excitonic superradiance.

  19. Water dispersible LiNdP{sub 4}O{sub 12} nanocrystals: New multifunctional NIR–NIR luminescent materials for bio-applications

    Energy Technology Data Exchange (ETDEWEB)

    Marciniak, L., E-mail: l.marciniak@int.pan.wroc.pl [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Okólna 2, 50-422 Wroclaw (Poland); Prorok, K.; Bednarkiewicz, A. [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Okólna 2, 50-422 Wroclaw (Poland); Department of Nanotechnology, Wroclaw Research Centre EIT+, Stabłowicka 147, 54-066 Wrocław (Poland); Kowalczyk, A. [Department of Nanotechnology, Wroclaw Research Centre EIT+, Stabłowicka 147, 54-066 Wrocław (Poland); Hreniak, D.; Strek, W. [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Okólna 2, 50-422 Wroclaw (Poland)

    2016-08-15

    The synthesis and luminescent properties of water colloidal solution of LiNdP{sub 4}O{sub 12} nanocrystals were presented together with demonstrations of their suitability for bio-imaging, remote nano-thermometry and hyperthermal therapy bio-applications. Due to efficient and photostable luminescence at 860 nm under ~808 nm excitation, NPs luminescence was measured in chicken breast at down to 30 mm depths. Moreover temperature dependent spectroscopic features were used in order to remotely measure the temperature of the local environment. Simultaneously, the most heavily Nd{sup 3+} doped NCs demonstrated intentional heating – under 1.5 W of excitation power at 800 nm, local 60 K photo-induced temperature rise was observed. The experimental confirmation of bioimaging of LiNdP{sub 4}O{sub 12} nanoparticles in HEK was presented.

  20. Unusual broadening of the NIR luminescence of Er{sup 3+}-doped Nb{sub 2}O{sub 5} nanocrystals embedded in silica host: Preparation and their structural and spectroscopic study for photonics applications

    Energy Technology Data Exchange (ETDEWEB)

    Aquino, Felipe Thomaz; Pereira, Rafael R. [Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Av. Bandeirantes, 3900, CEP 14040-901 Ribeirão Preto, SP (Brazil); Ferrari, Jefferson Luis [Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Av. Bandeirantes, 3900, CEP 14040-901 Ribeirão Preto, SP (Brazil); Grupo de Pesquisa em Química de Materiais – (GPQM), Departamento de Ciências Naturais, Universidade Federal de São João Del Rei, Campus Dom Bosco, Praça Dom Helvécio, 74, 36301-160 São João Del Rei, MG (Brazil); Ribeiro, Sidney José Lima [Laboratório de Materiais Fotônicos, Instituto de Química, UNESP, Caixa Postal 355, 14801-970 Araraquara, SP (Brazil); Ferrier, Alban; Goldner, Philippe [Chimie-Paristech, Laboratoire de Chimie de la Matière Condensée de Paris, CNRS-UMR 7574, UPMC Univ Paris 06, 11 Rue Pierre et Marie Curie, 75005 Paris (France); and others

    2014-10-15

    This paper reports on the preparation of novel sol-gel erbium-doped SiO{sub 2}-based nanocomposites embedded with Nb{sub 2}O{sub 5} nanocrystals fabricated using a bottom-up method and describes their structural, morphological, and luminescence characterization. To prepare the glass ceramics, we synthesized xerogels containing Si/Nb molar ratios of 90:10 up to 50:50 at room temperature, followed by annealing at 900, 1000, or 1100 °C for 10 h. We identified crystallization accompanying host densification in all the nanocomposites with orthorhombic (T-phase) or monoclinic (M-phase) Nb{sub 2}O{sub 5} nanocrystals dispersed in the amorphous SiO{sub 2} phase, depending on the niobium content and annealing temperature. A high-intensity broadband emission in the near-infrared region assigned to the {sup 4}I{sub 13/2} → {sup 4}I{sub 15/2} transition of the Er{sup 3+} ions was registered for all the nanocomposites. The shape and the bandwidth changed with the Nb{sub 2}O{sub 5} crystalline phase, with values achieving up to 81 nm. Er{sup 3+} ions were located mainly in Nb{sub 2}O{sub 5}-rich regions, and the complex structure of the different Nb{sub 2}O{sub 5} polymorphs accounted for the broadening in the emission spectra. The materials containing the T-phase, displayed higher luminescence intensity, longer {sup 4}I{sub 13/2} lifetime and broader bandwidth. In conclusion, these nanostructured materials are potential candidates for photonic applications like optical amplifiers and WDM devices operating in the S, C, and L telecommunication bands. - Highlights: • Rare earth doped Nb{sub 2}O{sub 5} nanocrystals prepared from a bottom-up approach. • Unusual broadband NIR emission in glass ceramic system. • Structural features tuning the luminescence properties. • Potential as optical amplifiers and WDM devices. • Photonic devices operating in the S, C, and L telecommunication.

  1. Strong band edge luminescence from InN films grown on Si substrates by electron cyclotron resonance-assisted molecular beam epitaxy

    International Nuclear Information System (INIS)

    Yodo, Tokuo; Yona, Hiroaki; Ando, Hironori; Nosei, Daiki; Harada, Yoshiyuki

    2002-01-01

    We observed strong band edge luminescence at 8.5-200 K from 200-880 nm thick InN films grown on 10 nm thick InN buffer layers on Si(001) and Si(111) substrates by electron cyclotron resonance-assisted molecular beam epitaxy. The InN film on the Si(001) substrate exhibited strong band edge photoluminescence (PL) emission at 1.814 eV at 8.5 K, tentatively assigned as donor to acceptor pair [DAP (α-InN)] emission from wurtzite-InN (α-InN) crystal grains, while those on Si(111) showed other stronger band edge PL emissions at 1.880, 2.081 and 2.156 eV, tentatively assigned as donor bound exciton [D 0 X(α-InN)] from α-InN grains, DAP (β-InN) and D 0 X (β-InN) emissions from zinc blende-InN (β-InN) grains, respectively

  2. New features of hot intraband luminescence for fast timing

    International Nuclear Information System (INIS)

    Omelkov, S.I.; Nagirnyi, V.; Vasil'ev, A.N.; Kirm, M.

    2016-01-01

    Intraband luminescence (IBL) is a prompt emission originating from the radiative intraband transitions of charge carriers during thermalisation. Despite its low intensity, IBL can hopefully enhance scintillation time resolution, for instance, in positron emission tomography. The continuous and structureless spectrum of IBL spans over the whole transparency region of a material. Exploiting a wide spectral sensitivity range of our instrumentation (0.77–10.6 eV), we have discovered a strong rise of IBL spectral yield in the NIR region in all studied compounds, which could not be explained within the available theoretical models of IBL. We have developed a new model attributing the NIR rise of the IBL spectrum to the phonon-assisted electron transitions within a single parabolic energy band, which yields a fair correspondence to our experimental data.

  3. New features of hot intraband luminescence for fast timing

    Energy Technology Data Exchange (ETDEWEB)

    Omelkov, S.I., E-mail: omelkovs@gmail.com [Institute of Physics, University of Tartu, W.Ostwaldi 1, Tartu 50411 (Estonia); Nagirnyi, V. [Institute of Physics, University of Tartu, W.Ostwaldi 1, Tartu 50411 (Estonia); Vasil' ev, A.N. [Skobeltsyn Institute of Nuclear Physics, M.V. Lomonosov Moscow State University, Moscow 119991 (Russian Federation); Kirm, M. [Institute of Physics, University of Tartu, W.Ostwaldi 1, Tartu 50411 (Estonia)

    2016-08-15

    Intraband luminescence (IBL) is a prompt emission originating from the radiative intraband transitions of charge carriers during thermalisation. Despite its low intensity, IBL can hopefully enhance scintillation time resolution, for instance, in positron emission tomography. The continuous and structureless spectrum of IBL spans over the whole transparency region of a material. Exploiting a wide spectral sensitivity range of our instrumentation (0.77–10.6 eV), we have discovered a strong rise of IBL spectral yield in the NIR region in all studied compounds, which could not be explained within the available theoretical models of IBL. We have developed a new model attributing the NIR rise of the IBL spectrum to the phonon-assisted electron transitions within a single parabolic energy band, which yields a fair correspondence to our experimental data.

  4. Violet-green excitation for NIR luminescence of Yb3+ ions in Bi2O3-B2O3-SiO2-Ga2O3 glasses.

    Science.gov (United States)

    Li, Weiwei; Cheng, Jimeng; Zhao, Guoying; Chen, Wei; Hu, Lili; Guzik, Malgorzata; Boulon, Georges

    2014-04-21

    60Bi(2)O(3)-20B(2)O(3)-10SiO(2)-10Ga(2)O(3) glasses doped with 1-9 mol% Yb(2)O(3) were prepared and investigated mainly on their violet-green excitation for the typical NIR emission of Yb(3+), generally excited in the NIR. Two violet excitation bands at 365 nm and 405 nm are related to Yb(2+) and Bi(3+). 465 nm excitation band and 480 nm absorption band in the blue-green are assigned to Bi(0) metal nanoparticles/grains. Yb-content-dependence of the excitation and absorption means that Bi(0) is the reduced product of Bi(3+), but greatly competed by the redox reaction of Yb(2+) ↔ Yb(3+). It is proved that the violet-green excitations result in the NIR emission of Yb(3+). On the energy transfer, the virtual level of Yb(3+)-Yb(3+) as well as Bi(0) dimers probably plays an important role. An effective and controllable way is suggested to achieve nano-optical applications by Bi(0) metal nanoparticles/grains and Yb(3+).

  5. 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.

  6. 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.

  7. Anodization of aluminium thin films on p{sup ++}Si and annihilation of strong luminescence from Al{sub 2}O{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Efeoglu, Hasan, E-mail: hefeoglu@atauni.edu.t [Atatuerk University, Faculty of Engineering, Department of Electrical and Electronics Engineering, 25240 Erzurum (Turkey); Karacali, Tevhit [Atatuerk University, Faculty of Engineering, Department of Electrical and Electronics Engineering, 25240 Erzurum (Turkey); Meral, Kadem; Erdogan, Ibrahim Y.; Onganer, Yavuz [Atatuerk University, Faculty of Sciences, Department of Chemistry, 25240 Erzurum (Turkey)

    2010-01-15

    Photoluminescence (PL) of Al{sub 2}O{sub 3} films obtained by anodization of thermally evaporated and annealed thin Al films on p{sup ++}Si in 0.3 M oxalic acid has been investigated. Thermal annealing at 200-950 deg. C under the dry nitrogen atmosphere was used for deactivation of luminescence centres. Luminescence from as grown films was broad and located at 425 nm. This luminescence reached to highest level after annealing at 600 deg. C. Maximum 10 min was required for full optical activation and prolonged annealing up to 4 h did not change the luminescence intensity. Because of deep levels, absorption band edge of as grown films was shifted to the lower energy which is 3.25 eV. Annealing above 800 deg. C reduced the PL intensity and this observation was correlated with the blue shift of band edge as the defects annealed out. Disappearing PL intensity and blue shift of band edge absorption after annealing at 950 deg. C was mainly attributed to the oxygen-related defects and partly to impurities that may be originated from oxalic acid. AFM results did not show any hexagonally ordered holes but uniformly distributed nanosized Al{sub 2}O{sub 3} clusters that were clearly seen. XRD measurements on as grown Al{sub 2}O{sub 3} showed only [1 1 0] direction of alpha phase. Debye-Scherer calculation for this line indicates that cluster size is 35.7 nm. XRD and AFM pictures suggest that nanocrystalline Al{sub 2}O{sub 3} are embedded in amorphous Al{sub 2}O{sub 3}.

  8. 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

  9. 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.

  10. 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

  11. 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.

  12. 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

  13. 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.

  14. The Exciton-Polariton Dispersion Law under the Action of Strong Pumping in the Region of the M-Band of Luminescence

    Science.gov (United States)

    Khadzhi, P. I.; Nad'kin, L. Yu.; Markov, D. A.

    2018-04-01

    The double-pulse interaction with excitons and biexcitons in semiconductors is studied theoretically. It is shown that the dispersion law of carrier wave has three branches under the action of a powerful pumping in the region of the M-band of luminescence. Values of parameters at which the dispersion law branches can intersect due to the degeneration of the exciton level energy have been found. The effect of a significant change in the force of coupling between the exciton and photon of a weak pulse with a change in the pumping intensity is predicted.

  15. Improving NIR snow pit stratigraphy observations by introducing a controlled NIR light source

    Science.gov (United States)

    Dean, J.; Marshall, H.; Rutter, N.; Karlson, A.

    2013-12-01

    Near-infrared (NIR) photography in a prepared snow pit measures mm-/grain-scale variations in snow structure, as reflectivity is strongly dependent on microstructure and grain size at the NIR wavelengths. We explore using a controlled NIR light source to maximize signal to noise ratio and provide uniform incident, diffuse light on the snow pit wall. NIR light fired from the flash is diffused across and reflected by an umbrella onto the snow pit; the lens filter transmits NIR light onto the spectrum-modified sensor of the DSLR camera. Lenses are designed to refract visible light properly, not NIR light, so there must be a correction applied for the subsequent NIR bright spot. To avoid interpolation and debayering algorithms automatically performed by programs like Adobe's Photoshop on the images, the raw data are analyzed directly in MATLAB. NIR image data show a doubling of the amount of light collected in the same time for flash over ambient lighting. Transitions across layer boundaries in the flash-lit image are detailed by higher camera intensity values than ambient-lit images. Curves plotted using median intensity at each depth, normalized to the average profile intensity, show a separation between flash- and ambient-lit images in the upper 10-15 cm; the ambient-lit image curve asymptotically approaches the level of the flash-lit image curve below 15cm. We hypothesize that the difference is caused by additional ambient light penetrating the upper 10-15 cm of the snowpack from above and transmitting through the wall of the snow pit. This indicates that combining NIR ambient and flash photography could be a powerful technique for studying penetration depth of radiation as a function of microstructure and grain size. The NIR flash images do not increase the relative contrast at layer boundaries; however, the flash more than doubles the amount of recorded light and controls layer noise as well as layer boundary transition noise.

  16. NIRS in Space?

    Science.gov (United States)

    Peterson, David L.; Condon, Estelle (Technical Monitor)

    2000-01-01

    Proponents of near infrared reflectance spectroscopy (NIRS) have been exceptionally successful in applying NIRS techniques to many instances of organic material analyses. While this research and development began in the 1950s, in recent years, stimulation of advancements in instrumentation is allowing NIRS to begin to find its way into the food processing systems, into food quality and safety, textiles and much more. And, imaging high spectral resolution spectrometers are now being evaluated for the rapid scanning of foodstuffs, such as the inspection of whole chicken carcasses for fecal contamination. The imaging methods are also finding their way into medical applications, such as the non-intrusive monitoring of blood oxygenation in newborns. Can these scientific insights also be taken into space and successfully used to measure the Earth's condition? Is there an analog between the organic analyses in the laboratory and clinical settings and the study of Earth's living biosphere? How are the methods comparable and how do they differ?

  17. Decoding vigilance with NIRS.

    Science.gov (United States)

    Bogler, Carsten; Mehnert, Jan; Steinbrink, Jens; Haynes, John-Dylan

    2014-01-01

    Sustained, long-term cognitive workload is associated with variations and decrements in performance. Such fluctuations in vigilance can be a risk factor especially during dangerous attention demanding activities. Functional MRI studies have shown that attentional performance is correlated with BOLD-signals, especially in parietal and prefrontal cortical regions. An interesting question is whether these BOLD-signals could be measured in real-world scenarios, say to warn in a dangerous workplace whenever a subjects' vigilance is low. Because fMRI lacks the mobility needed for such applications, we tested whether the monitoring of vigilance might be possible using Near-Infrared Spectroscopy (NIRS). NIRS is a highly mobile technique that measures hemodynamics in the surface of the brain. We demonstrate that non-invasive NIRS signals correlate with vigilance. These signals carry enough information to decode subjects' reaction times at a single trial level.

  18. Decoding vigilance with NIRS.

    Directory of Open Access Journals (Sweden)

    Carsten Bogler

    Full Text Available Sustained, long-term cognitive workload is associated with variations and decrements in performance. Such fluctuations in vigilance can be a risk factor especially during dangerous attention demanding activities. Functional MRI studies have shown that attentional performance is correlated with BOLD-signals, especially in parietal and prefrontal cortical regions. An interesting question is whether these BOLD-signals could be measured in real-world scenarios, say to warn in a dangerous workplace whenever a subjects' vigilance is low. Because fMRI lacks the mobility needed for such applications, we tested whether the monitoring of vigilance might be possible using Near-Infrared Spectroscopy (NIRS. NIRS is a highly mobile technique that measures hemodynamics in the surface of the brain. We demonstrate that non-invasive NIRS signals correlate with vigilance. These signals carry enough information to decode subjects' reaction times at a single trial level.

  19. Relative Contribution of nirK- and nirS- Bacterial Denitrifiers as Well as Fungal Denitrifiers to Nitrous Oxide Production from Dairy Manure Compost.

    Science.gov (United States)

    Maeda, Koki; Toyoda, Sakae; Philippot, Laurent; Hattori, Shohei; Nakajima, Keiichi; Ito, Yumi; Yoshida, Naohiro

    2017-12-19

    The relative contribution of fungi, bacteria, and nirS and nirK denirifiers to nitrous oxide (N 2 O) emission with unknown isotopic signature from dairy manure compost was examined by selective inhibition techniques. Chloramphenicol (CHP), cycloheximide (CYH), and diethyl dithiocarbamate (DDTC) were used to suppress the activity of bacteria, fungi, and nirK-possessing denitrifiers, respectively. Produced N 2 O were surveyed to isotopocule analysis, and its 15 N site preference (SP) and δ 18 O values were compared. Bacteria, fungi, nirS, and nirK gene abundances were compared by qPCR. The results showed that N 2 O production was strongly inhibited by CHP addition in surface pile samples (82.2%) as well as in nitrite-amended core samples (98.4%), while CYH addition did not inhibit the N 2 O production. N 2 O with unknown isotopic signature (SP = 15.3-16.2‰), accompanied by δ 18 O (19.0-26.8‰) values which were close to bacterial denitrification, was also suppressed by CHP and DDTC addition (95.3%) indicating that nirK denitrifiers were responsible for this N 2 O production despite being less abundant than nirS denitrifiers. Altogether, our results suggest that bacteria are important for N 2 O production with different SP values both from compost surface and pile core. However, further work is required to decipher whether N 2 O with unknown isotopic signature is mostly due to nirK denitrifiers that are taxonomically different from the SP-characterized strains and therefore have different SP values rather than also being interwoven with the contribution of the NO-detoxifying pathway and/or of co-denitrification.

  20. 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) ...

  1. 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

  2. The Intersection of CMOS Microsystems and Upconversion Nanoparticles for Luminescence Bioimaging and Bioassays

    Directory of Open Access Journals (Sweden)

    Liping Wei

    2014-09-01

    Full Text Available Organic fluorophores and quantum dots are ubiquitous as contrast agents for bio-imaging and as labels in bioassays to enable the detection of biological targets and processes. Upconversion nanoparticles (UCNPs offer a different set of opportunities as labels in bioassays and for bioimaging. UCNPs are excited at near-infrared (NIR wavelengths where biological molecules are optically transparent, and their luminesce in the visible and ultraviolet (UV wavelength range is suitable for detection using complementary metal-oxide-semiconductor (CMOS technology. These nanoparticles provide multiple sharp emission bands, long lifetimes, tunable emission, high photostability, and low cytotoxicity, which render them particularly useful for bio-imaging applications and multiplexed bioassays. This paper surveys several key concepts surrounding upconversion nanoparticles and the systems that detect and process the corresponding luminescence signals. The principle of photon upconversion, tuning of emission wavelengths, UCNP bioassays, and UCNP time-resolved techniques are described. Electronic readout systems for signal detection and processing suitable for UCNP luminescence using CMOS technology are discussed. This includes recent progress in miniaturized detectors, integrated spectral sensing, and high-precision time-domain circuits. Emphasis is placed on the physical attributes of UCNPs that map strongly to the technical features that CMOS devices excel in delivering, exploring the interoperability between the two technologies.

  3. On children's dyslexia with NIRS

    Science.gov (United States)

    Gan, Zhuo; Li, Chengjun; Gong, Hui; Luo, Qingming; Yao, Bin; Song, Ranran; Wu, Hanrong

    2003-12-01

    Developmental dyslexia is a kind of prevalent psychologic disease. Some functional imaging technologies, such as FMRI and PET, have been used to study the brain activities of dyslexics. NIRS is a kind of novel technology which is more and more widely being used for study of the cognitive psychology. However, there aren"t reports about the dyslexic research using NIRS to be found until now. This paper introduces a NIRS system of four measuring channels. Brain activities of dyslexic subjects and normal subjects during reading task were studied with the NIRS system. Two groups of subjects, the group of dyslexia and the group of normal, were appointed to perform two reading tasks. At the same time, their cortical activities were measured with the NIRS system. This experimental result indicates that the brain activities of the dyslexic group were significantly higher than the control group in BA 48 and that NIRS can be used for the study of human brain activity.

  4. 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)

  5. New luminescence measurement facilities in retrospective dosimetry

    DEFF Research Database (Denmark)

    Lapp, Torben; Jain, Mayank; Thomsen, Kristina Jørkov

    2012-01-01

    ), this facility has been used to measure natural doses in feldspar using the decaying NIR RL signal.Secondly, we present a method for mapping radiation field of the built-in 90Sr/90Y β-source and estimating grain-location specific dose-rates. This is important for the accuracy of single grain results, when......This paper gives a review of recent developments in luminescence measurement facilities on the Risø TL/OSL reader including radio-luminescence (RL), exo-electron and violet stimulation attachments, and a method for characterising and if necessary correcting for beta irradiation source non...... radiation field is spatially non-uniform across the sample area. We document the effect of this correction method and further investigate on the effect of lifting the source to achieve a better dose-rate uniformity.Finally we summarise two recently-developed novel facilities to help investigate (i) the time...

  6. 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....

  7. NIR annual report 1987

    International Nuclear Information System (INIS)

    1988-01-01

    The fourth annual report of the Niedersaechsisches Institut fuer Radiooekologie (NIR) is intended to describe the scientific work of the institute and its members in 1987. The central part of this publication are the fourteen reports on scientific activities, to be divided into four large categories: - Behaviour of tritium in the atmosphere and the soil - on this, important new knowledge was gained in 1987 in an experiment in Canada on the release of this substance; - Investigations in the radioecology of iodine 129, the dependence of its mobility in the soil on humus substances and microorganisms, and its enrichment in the human thyroid gland; - Establishment of transfer factors in the food chain for fission products like cesium 137, cesium 134 and strontium 90 - this being a field where exact knowledge has regained great importance after the accident at Chernobyl; - Aerosol-physical investigations: on the one hand, to obtain data on the propagation of nutrient aerosols and aerosols carrying harmful substances in areas with vegetation, and on the other hand to measure 'snow-out' and 'fog-out' coefficients. To this are added a number of papers on the stability of the decontamination substance for cesium 137 - ammonium-iron-hexacyanoferrate (AIHCF) - in the soil, on the translocation of cesium in apple-trees, and on the improvement of the analytics for uranium and plutonium in environmental specimens. (orig./MG) [de

  8. Microbeam facility at NIRS

    International Nuclear Information System (INIS)

    Sato, Yukio; Yamaguchi, Hiroshi

    2000-01-01

    Radiation biophysics or microdosimetry has suggested radiation effect mechanism. Full understanding of it has not yet been obtained. There are vast variety of events in physical, chemical and biological processes from at the time of irradiation to biological endpoints. Analysis of RBE-LET relation for biological endpoints like survival, mutation and transformation in cultured mammalian cells is still the leading subject to study the physical processes. The biological and repair processes have been studied phenomenologically through dose rate effect or fractionation experiment. Human genome project has accelerated biological sciences as a whole taking methodology of the molecular biology, where the mechanism is explained by molecules involved. We have thus to know entity and its (biological) function in every single process. Molecular biological approach in radiation biology has started and revealed several proteins being involved in the repair processes. Quantitative relation between phenomenological data like cell survivals and molecular processes, however, has been little known yet. A promising approach to fill this gap should be the study by microbeam, which enables us to see, for example, a deletion in chromosomal level by a single particle traverse of cell nucleus and may suggest possible molecular processes. Under this motivation we started feasibility study on installation of a microbeam port in our Tandem accelerator (5.1 MeV 4 He 2+ ). We have planned to adopt a lens focusing and a scanning system developed (by the Oxford microbeam Ltd) for the existing micro PIXE system in NIRS, which has basically achieved irradiation to a cell within a position resolution of 2 micrometer. There are two practical requirements, i.e. precise positioning and faster irradiation. These are described including research subjects planned. (author)

  9. Persistent luminescence nanothermometers

    Science.gov (United States)

    Martín Rodríguez, Emma; López-Peña, Gabriel; Montes, Eduardo; Lifante, Ginés; García Solé, José; Jaque, Daniel; Diaz-Torres, Luis Armando; Salas, Pedro

    2017-08-01

    Persistent phosphorescence nanoparticles emitting in the red and near-infrared spectral regions are strongly demanded as contrast nanoprobes for autofluorescence free bioimaging and biosensing. In this work, we have developed Sr4Al14O25:Eu2+, Cr3+, Nd3+ nanopowders that produce persistent red phosphorescence peaking at 694 nm generated by Cr3+ ions. This emission displays temperature sensitivity in the physiological temperature range (20-60 °C), which makes these nanoparticles potentially useful as fluorescence (contactless) nanothermometers operating without requiring optical excitation. Nd3+ ions, which act as shallow electron traps for the red Cr3+ persistent emission, also display infrared emission bands, extending the fluorescence imaging capability to the second biological window. This unique combination of properties makes these nanoparticles multifunctional luminescent probes with great potential applications in nanomedicine.

  10. Photo-, thermo- and optically stimulated luminescence of monoclinic zirconia

    Energy Technology Data Exchange (ETDEWEB)

    Kiisk, Valter, E-mail: valter.kiisk@ut.ee [Institute of Physics, University of Tartu, Ravila 14c, 50411 Tartu (Estonia); Puust, Laurits; Utt, Kathriin; Maaroos, Aarne; Mändar, Hugo [Institute of Physics, University of Tartu, Ravila 14c, 50411 Tartu (Estonia); Viviani, Erica; Piccinelli, Fabio [Department of Biotechnology, University of Verona, Strada Le Grazie 15, 37134 Verona (Italy); Saar, Rando; Joost, Urmas; Sildos, Ilmo [Institute of Physics, University of Tartu, Ravila 14c, 50411 Tartu (Estonia)

    2016-06-15

    We carried out a careful photoluminescence (PL) and thermoluminescence (TL) characterization of nominally pure monoclinic ZrO{sub 2} nanopowders subject to oxidative vs reductive annealing (up to 1450 °C). The two kinds of studied zirconia (sol-gel-prepared vs commercial powder) exhibited virtually identical 490 nm PL emission band and 280 nm PL excitation band with slight, but clearly detectable variations in the spectral shape. The TL glow peaks, recorded over the temperature range −100 to 300 °C, showed an interplay depending on the type and treatment of sample. There is a strong evidence that the −35 and 205 °C glow peaks are due to oxygen vacancies whereas the 5 °C glow peak may relate to oxygen interstitials and the 110 °C glow peak to surface defects. Although a number of distinct glow peaks emerge, the material still seems to contain a quasi-continuous distribution of trap depths. In comparison to TL, we also demonstrate effective optically stimulated luminescence (OSL) from this polymorph of ZrO{sub 2} under red and NIR illumination at ~1 W/cm{sup 2}. All traps responsible for the principal TL peaks were also found to be OSL-active, which widens the applied importance of the material.

  11. Annealing temperatures influence luminescence of YBO{sub 3}: Ce{sup 3+}, Yb{sup 3+} prepared by solvothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yue [Department of Physics, Northwest University, No. 229 Taibai North Road, Xi' an, Shaanxi, 710069 (China); Hu, Xiaoyun, E-mail: hxy3275@nwu.edu.cn [Department of Physics, Northwest University, No. 229 Taibai North Road, Xi' an, Shaanxi, 710069 (China); Zhan, Suchang; Sun, Xiao; Wang, Zhizhong; Miao, Tian; Miao, Hui [Department of Physics, Northwest University, No. 229 Taibai North Road, Xi' an, Shaanxi, 710069 (China); Fan, Jun [School of Chemical Engineering, Northwest University, No. 229 Taibai North Road, Xi' an, Shaanxi, 710069 (China)

    2014-08-01

    Near-infrared (NIR) quantum cutting (QC) YBO{sub 3}: Ce{sup 3+}, Yb{sup 3+} phosphors have been synthesized by solvothermal method with further heat treatment. The emission spectrum shows the Vis and NIR emission intensity of samples are both increasingly strong as annealing temperature rises when the annealing temperature is above 600 °C. Meanwhile the Vis emission of unannealed sample is observed. SEM images show that the sample annealed at different temperatures (200–900 °C) is mainly composed of nanosheets like potato chips, which is melt down granules after annealing treatment above 1000 °C.The crystal texture of all samples whether annealed or not is hexagonal through the analysis of XRD. The Raman and infrared spectrums indicate that the boron ions exist of BO{sub 4} units when the annealing temperature is above 600 °C. The infrared profile of unannealed sample shows that there are N–H units in the samples without annealing treatment. - Highlights: • The nanosheets like potato chips are synthesized by solvothermal method. • Annealing temperature is a great effect for luminescence of sample. • The boron ions exist of BO{sub 4} when the annealing temperature is above 600 °C, whose quantity determines the luminescent intensity. • According to the infrared profile of unannealed sample, there are N–H units, which are beneficial to the Vis emission.

  12. 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.

  13. Near-infrared (NIR) optogenetics using up-conversion system

    Science.gov (United States)

    Hososhima, Shoko; Yuasa, Hideya; Ishizuka, Toru; Yawo, Hiromu

    2015-03-01

    Non-invasive remote control technologies designed to manipulate neural functions for a comprehensive and quantitative understanding of the neuronal network in the brain as well as for the therapy of neurological disorders have long been awaited. Recently, it has become possible to optically manipulate the neuronal activity using biological photo-reactive molecules such as channelrhodopsin-2 (ChR2). However, ChR2 and its relatives are mostly reactive to visible light which does not effectively penetrate through biological tissues. In contrast, near-infrared (NIR) light penetrates deep into the tissues because biological systems are almost transparent to light within this so-called `imaging window'. Here we used lanthanide nanoparticles (LNPs), which are composed of rare-earth elements, as luminous bodies to activate channelrhodopsins (ChRs) since they absorb low-energy NIR light to emit high-energy visible light (up-conversion). Neuron-glioma-hybrid ND-7/23 cells were cultured with LNP(NaYF4:Sc/Yb/Er) particles (peak emission, 543 nm) and transfected to express C1V1 (peak absorbance, 539 nm), a chimera of ChR1 and VChR1. The photocurrents were generated in response to NIR laser light (976 nm) to a level comparable to that evoked by a filtered Hg lamp (530-550 nm). NIR light pulses also evoked action potentials in the cultured neurons that expressed C1V1. It is suggested that the green luminescent light emitted from LNPs effectively activated C1V1 to generate the photocurrent. With the optimization of LNPs, acceptor photo-reactive biomolecules and optics, this system could be applied to non-invasively actuate neurons deep in the brain.

  14. NIR detects, destroys insect pests

    International Nuclear Information System (INIS)

    McGraw, L.C.

    1998-01-01

    What’s good for Georgia peanuts may also be good for Kansas wheat. An electric eye that scans all food-grade peanuts for visual defects could one day do the same for wheat kernels. For peanuts, it’s a proven method for monitoring quality. In wheat, scanning with near-infrared (NIR) energy can reveal hidden insect infestations that lower wheat quality. ARS entomologists James E. Throne and James E. Baker and ARS agricultural engineer Floyd E. Dowell are the first to combine NIR with an automated grain-handling system to rapidly detect insects hidden in single wheat kernels

  15. 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.

  16. 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)

  17. Upconversion luminescence and blackbody radiation in tetragonal YSZ co-doped with Tm(3+) and Yb(3+).

    Science.gov (United States)

    Soares, M R N; Ferro, M; Costa, F M; Monteiro, T

    2015-12-21

    Lanthanide doped inorganic nanoparticles with upconversion luminescence are of utmost importance for biomedical applications, solid state lighting and photovoltaics. In this work we studied the downshifted luminescence, upconversion luminescence (UCL) and blackbody radiation of tetragonal yttrium stabilized zirconia co-doped with Tm(3+) and Yb(3+) single crystals and nanoparticles produced by laser floating zone and laser ablation in liquids, respectively. The photoluminescence (PL) and PL excitation (PLE) were investigated at room temperature (RT). PL spectra exhibit the characteristic lines in UV, blue/green, red and NIR regions of the Tm(3+) (4f(12)) under resonant excitation into the high energy (2S+1)LJ multiplets. Under NIR excitation (980 nm), the samples placed in air display an intense NIR at ∼800 nm due to the (1)G4→(3)H5/(3)H4→(3)H6 transitions. Additionally, red, blue/green and ultraviolet UCL is observed arising from higher excited (1)G4 and (1)D2 multiplets. The power excitation dependence of the UCL intensity indicated that 2-3 low energy absorbed photons are involved in the UCL for low power levels, while for high powers, the identified saturation is dependent on the material size with a enhanced effect on the NPs. The temperature dependence of the UCL was investigated for single crystals and targets used in the ablation. An overall increase of the integrated intensity was found to occur between 12 K and the RT. The thermally activated process is described by activation energies of 10 meV and 30 meV for single crystals and targets, respectively. For the NPs, the UCL was found to be strongly sensitive to pressure conditions. Under vacuum conditions, instead of the narrow lines of the Tm(3+), a wide blackbody radiation was detected, responsible for the change in the emission colour from blue to orange. This phenomenon is totally reversible when the NPs are placed at ambient pressure. The UCL/blackbody radiation in the nanosized material exhibits

  18. Co-precipitation synthesis and upconversion luminescence ...

    Indian Academy of Sciences (India)

    ... light: strong green (539 nm), weak red (670 nm) and near-infrared (760 nm). The upconversion luminescence is based on two-photon absorption by the energy transfer from the donor (Yb3+) to the acceptor (Ho3+). All the results indicate that ZrO2:Yb3+-Ho3+ phosphors could be a promising biological labelling material.

  19. Correlation of in vivo tumor response and singlet oxygen luminescence detection in mTHPC-mediated photodynamic therapy

    Directory of Open Access Journals (Sweden)

    Brian C. Wilson

    2015-01-01

    Full Text Available Excited-state singlet oxygen (1O2, generated during photodynamic therapy (PDT, is believed to be the primary cytotoxic agent with a number of clinically approved photosensitizers. Its relative concentration in cells or tissues can be measured directly through its near-infrared (NIR luminescence emission, which has correlated well with in vitro cell and in vivo normal skin treatment responses. Here, its correlation with the response of tumor tissue in vivo is examined, using the photosensitizer meso-tetrahydroxyphenylchlorin (mTHPC in an animal model comprising luciferase- and green fluorescent protein (GFP-transduced gliosarcoma grown in a dorsal window chamber. The change in the bioluminescence signal, imaged pretreatment and at 2, 5 and 9 d post treatment, was used as a quantitative measure of the tumor response, which was classified in individual tumors as "non", "moderate" and "strong" in order to reduce the variance in the data. Plotting the bioluminescence-based response vs the 1O2 counts demonstrated clear correlation, indicating that 1O2 luminescence provides a valid dosimetric technique for PDT in tumor tissue.

  20. 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

  1. 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)

  2. 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.

  3. Using Massive Multivariate NIRS Data in Ryegrass

    DEFF Research Database (Denmark)

    Edriss, Vahid; Greve-Pedersen, Morten; Jensen, Christian S

    2015-01-01

    Near infrared spectroscopy (NIRS) analytical techniques is a simple, fast and low cost method of high dimensional phenotyping compared to usual chemical techniques. To use this method there is no need for special sample preparation. The aim of this study is to use NIRS data to predict plant traits...... (e.g. dry matter, protein content, etc.) for the next generation. In total 1984 NIRS data from 995 ryegrass families (first cut) were used. The Absorption of radiation in the region of 960 – 1690 nm in every 2 nm distance produced 366 bins to represent the NIRS spectrum. The amount of genetic...

  4. Color-tunable up-conversion emission of luminescent-plasmonic, core/shell nanomaterials – KY{sub 3}F{sub 10}:Yb{sup 3+},Tm{sup 3+}/SiO{sub 2}-NH{sub 2}/Au

    Energy Technology Data Exchange (ETDEWEB)

    Runowski, Marcin, E-mail: runowski@amu.edu.pl

    2017-06-15

    Multifunctional luminescent-plasmonic KY{sub 3}F{sub 10}:Yb{sup 3+},Tm{sup 3+}/SiO{sub 2}-NH{sub 2}/Au nanomaterials were successfully obtained. The lanthanide-doped fluoride nanoparticles (NPs), synthesized under hydrothermal conditions exhibited bright blue up-conversion luminescence (λ{sub ex}=980 nm). Such lanthanide nanocrystals (20–40 nm) were coated with amine modified silica shell, forming core/shell nanostructures. Their surface was further uniformly covered with ultra-small gold NPs (4–7 nm). The as-prepared luminescent-plasmonic core/shell nanomaterials exhibited tunable up-conversion emission, due to the interactions between plasmonic and luminescent phases. The emission of Tm{sup 3+} ion was affected by the surface Au NPs, which exhibited strong plasmonic absorption in the visible range (450–650 nm). The increasing amount of the surface Au NPs, led to the significant alterations in a ratio of the Tm{sup 3+} emission bands. The NIR band ({sup 3}H{sub 4}→{sup 3}H{sub 6}) was unchanged, whereas the ratio and relative intensity of the bands in a visible range ({sup 1}G{sub 4}→{sup 3}H{sub 6} and {sup 1}G{sub 4}→{sup 3}F{sub 4}) was altered. This led to the significant change of the emission spectra shape and influenced color of emission, tuning it from bright blue to blue-violet. The products obtained were characterized by transmission electron microscopy (TEM), energy dispersive X-ray analysis (EDX), powder X-ray diffraction (XRD), UV–vis absorption spectroscopy and luminescence spectroscopy (excitation/emission spectra and luminescence decay curves).

  5. Persistent luminescence of transition metal (Co, Ni...)-doped ZnGa2O4 phosphors for applications in the near-infrared range

    Science.gov (United States)

    Pellerin, Morgane; Castaing, Victor; Gourier, Didier; Chanéac, Corinne; Viana, Bruno

    2018-02-01

    Persistent luminescence materials present many applications including security lighting and bio-imaging. Many progresses have been made in the elaboration of persistent luminescent nanoparticles suitable for the first NIR partial transparency window (650 - 950 nm). Moving to the second and third near-infrared partial transparency windows (1000 nm - 1800 nm) allows further reducing of scattering, absorption and tissue autofluorescence effects. In this work, we present the synthesis of Co2+ and Ni2+ doped zinc-gallate nanoparticles with broad emission covering the NIR-II range. Site occupancy, energy levels, optical features and persistent phenomena are presented.

  6. 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.

  7. Instrumentation and method for measuring NIR light absorbed in tissue during MR imaging in medical NIRS measurements

    Science.gov (United States)

    Myllylä, Teemu S.; Sorvoja, Hannu S. S.; Nikkinen, Juha; Tervonen, Osmo; Kiviniemi, Vesa; Myllylä, Risto A.

    2011-07-01

    Our goal is to provide a cost-effective method for examining human tissue, particularly the brain, by the simultaneous use of functional magnetic resonance imaging (fMRI) and near-infrared spectroscopy (NIRS). Due to its compatibility requirements, MRI poses a demanding challenge for NIRS measurements. This paper focuses particularly on presenting the instrumentation and a method for the non-invasive measurement of NIR light absorbed in human tissue during MR imaging. One practical method to avoid disturbances in MR imaging involves using long fibre bundles to enable conducting the measurements at some distance from the MRI scanner. This setup serves in fact a dual purpose, since also the NIRS device will be less disturbed by the MRI scanner. However, measurements based on long fibre bundles suffer from light attenuation. Furthermore, because one of our primary goals was to make the measuring method as cost-effective as possible, we used high-power light emitting diodes instead of more expensive lasers. The use of LEDs, however, limits the maximum output power which can be extracted to illuminate the tissue. To meet these requirements, we improved methods of emitting light sufficiently deep into tissue. We also show how to measure NIR light of a very small power level that scatters from the tissue in the MRI environment, which is characterized by strong electromagnetic interference. In this paper, we present the implemented instrumentation and measuring method and report on test measurements conducted during MRI scanning. These measurements were performed in MRI operating rooms housing 1.5 Tesla-strength closed MRI scanners (manufactured by GE) in the Dept. of Diagnostic Radiology at the Oulu University Hospital.

  8. Deep nirS amplicon sequencing of San Francisco Bay sediments enables prediction of geography and environmental conditions from denitrifying community composition.

    Science.gov (United States)

    Lee, Jessica A; Francis, Christopher A

    2017-12-01

    Denitrification is a dominant nitrogen loss process in the sediments of San Francisco Bay. In this study, we sought to understand the ecology of denitrifying bacteria by using next-generation sequencing (NGS) to survey the diversity of a denitrification functional gene, nirS (encoding cytchrome-cd 1 nitrite reductase), along the salinity gradient of San Francisco Bay over the course of a year. We compared our dataset to a library of nirS sequences obtained previously from the same samples by standard PCR cloning and Sanger sequencing, and showed that both methods similarly demonstrated geography, salinity and, to a lesser extent, nitrogen, to be strong determinants of community composition. Furthermore, the depth afforded by NGS enabled novel techniques for measuring the association between environment and community composition. We used Random Forests modelling to demonstrate that the site and salinity of a sample could be predicted from its nirS sequences, and to identify indicator taxa associated with those environmental characteristics. This work contributes significantly to our understanding of the distribution and dynamics of denitrifying communities in San Francisco Bay, and provides valuable tools for the further study of this key N-cycling guild in all estuarine systems. © 2017 Society for Applied Microbiology and John Wiley & Sons Ltd.

  9. Greenhouse cooling by NIR-reflection

    NARCIS (Netherlands)

    Hemming, S.; Kempkes, F.; Braak, van der N.; Dueck, T.A.; Marissen, A.

    2007-01-01

    Wageningen UR investigated the potential of several NIR-filtering methods to be applied in horticulture. In this paper the analysis of the optical properties of available NIR-filtering materials is given including a calculation method to quantify the energy reduction under these materials and to

  10. Recent Advance of Biological Molecular Imaging Based on Lanthanide-Doped Upconversion-Luminescent Nanomaterials

    Directory of Open Access Journals (Sweden)

    Yuanzeng Min

    2014-02-01

    Full Text Available Lanthanide-doped upconversion-luminescent nanoparticles (UCNPs, which can be excited by near-infrared (NIR laser irradiation to emit multiplex light, have been proven to be very useful for in vitro and in vivo molecular imaging studies. In comparison with the conventionally used down-conversion fluorescence imaging strategies, the NIR light excited luminescence of UCNPs displays high photostability, low cytotoxicity, little background auto-fluorescence, which allows for deep tissue penetration, making them attractive as contrast agents for biomedical imaging applications. In this review, we will mainly focus on the latest development of a new type of lanthanide-doped UCNP material and its main applications for in vitro and in vivo molecular imaging and we will also discuss the challenges and future perspectives.

  11. Near infrared and upconversion luminescence behaviour of Er3+/Yb3+ codoped boro-tellurite glasses

    Science.gov (United States)

    Maheshvaran, K.; Arunkumar, S.; Vijayakumar, R.; Marimuthu, K.

    2014-04-01

    The broadband NIR and upconversion luminescence behavior in a new series of Er3+/Yb3+ codoped TeO2-B2O3-SrO-BaO-Li2O-LiF glasses have been studied exciting at a wavelength of 980 nm using semiconductor laser. A broadband emission is observed from 1450 to 1650 nm with a full width at half maximum (FWHM) around 165 nm in 0.5wt% Yb3+ ion content E0.5YLTB glass. The radiative parameters such as transition probability (A), stimulated emission cross-section (σE), experimental and calculated branching ratios (βR), optical gain width (σp×FWHM) and radiative lifetime (τcal) have been calculated for the 4I13/2→4I15/2 NIR emission. Upconversion luminescence spectra of the prepared glasses have been studied and the ESA & ET processes have also been discussed and reported.

  12. 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

  13. 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

  14. [Induction and analysis for NIR features of frequently-used mineral traditional Chinese medicines].

    Science.gov (United States)

    Chen, Long; Yuan, Ming-Yang; Chen, Ke-Li

    2016-10-01

    In order to provide theoretical basis for the rapid identification of mineral traditional Chinese medicines(TCM) with near infrared (NIR)diffuse reflectance spectroscopy, Characteristic NIR spectra of 51 kinds of mineral TCMs were generalized and compared on the basis of the previous research, and the characteristic spectral bands were determined and analyzed by referring to mineralogical and geological literatures. It turned out that the NIR features of mineral TCMs were mainly at 8 000-4 000 cm ⁻¹ wavebands, which can be assigned as the absorption of water, -OH and[CO3 ²⁻] and so on. Absorption peaks of water has regularity as follows, the structure water and -OH had a combined peak which was strong and keen-edged around 7 000 cm ⁻¹, the crystal water had two strong peak around 7 000 cm ⁻¹ and 5 100 cm ⁻¹, and water only has a broad peak around 5 100 cm ⁻¹. Due to the differences in the crystal form and the contents of water in mineral TCMs, NIR features of water in mineral TCMs which could be used for identification were different. Mineral TCMs containing sulfate are rich in crystal water, mineral TCMs containing silicate generally had structure water, and mineral TCMs containing carbonate merely had a little of water, so it was reasonable for the use of NIR spectroscopy to classify mineral TCMs with anionic type. In addition, because of the differences in cationic type, impurities, crystal form and crystallinity, mineral TCMs have exclusive NIR features at 4 600-4 000 cm ⁻¹, which can be assigned as Al-OH, Mg-OH, Fe-OH, Si-OH,[CO3 ²⁻] and so on. Calcined mineral TCMs are often associated with water and main composition changes, also changes of the NIR features, which could be used for the monitoring of the processing, and to provide references for the quality control of mineral TCMs. The adaptability and limitation of NIR analysis for mineral TCMs were also discussed:the majority of mineral TCMs had noteworthy NIR features which could be

  15. Cr3+ and Cr4+ luminescence in glass ceramic silica

    International Nuclear Information System (INIS)

    Martines, Marco A.U.; Davolos, Marian R.; Jafelicci, Miguel Junior; Souza, Dione F. de; Nunes, Luiz A.O.

    2008-01-01

    This paper reports on the effect of glass ceramic silica matrix on [CrO 4 ] 4- and Cr 2 O 3 NIR and visible luminescence. Chromium-containing silica was obtained by precipitation from water-glass and chromium nitrate acid solution with thermal treatment at 1000 deg. C. From XRD results silica and silica-chromium samples are crystalline. The chromium emission spectrum presents two main broad bands: one in the NIR region (1.1-1.7μm) and other in the visible region (0.6-0.7μm) assigned to Cr 4+ and to Cr 3+ , respectively. This thermal treated glass ceramic silica-chromium sample stabilizes the [CrO 4 ] 4- where Cr 4+ substitutes for Si 4+ and also hexacoordinated Cr 3+ group probably as segregated phase in the system. It can be pointed out that luminescence spectroscopy is a powerful tool for detecting the two chromium optical centers in the glass ceramic silica

  16. Construction of Hierarchical Polymer Brushes on Upconversion Nanoparticles via NIR-Light-Initiated RAFT Polymerization.

    Science.gov (United States)

    Xie, Zhongxi; Deng, Xiaoran; Liu, Bei; Huang, Shanshan; Ma, Pingan; Hou, Zhiyao; Cheng, Ziyong; Lin, Jun; Luan, Shifang

    2017-09-13

    Photoinduced reversible addition-fragmentation chain transfer (RAFT) polymerization generally adopts high-energy ultraviolet (UV) or blue light. In combination with photoredox catalyst, the excitation light wavelength was extended to the visible and even near-infrared (NIR) region for photoinduced electron transfer RAFT polymerization. In this report, we introduce for the first time a surface NIR-light-initiated RAFT polymerization on upconversion nanoparticles (UCNPs) without adding any photocatalyst and construct a functional inorganic core/polymer shell nanohybrid for application in cancer theranostics. The multilayer core-shell UCNPs (NaYF 4 :Yb/Tm@NaYbF 4 :Gd@NaNdF 4 :Yb@NaYF 4 ), with surface anchorings of chain transfer agents, can serve as efficient NIR-to-UV light transducers for initiating the RAFT polymerization. A hierarchical double block copolymer brush, consisting of poly(acrylic acid) (PAA) and poly(oligo(ethylene oxide)methacrylate-co-2-(2-methoxy-ethoxy)ethyl methacrylate) (PEG for short), was grafted from the surface in sequence. The targeting arginine-glycine-aspartic (RGD) peptide was modified at the end of the copolymer through the trithiolcarbonate end group. After loading of doxorubicin, the UCNPs@PAA-b-PEG-RGD exhibited an enhanced U87MG cancer cell uptake efficiency and cytotoxicity. Besides, the unique upconversion luminescence of the nanohybrids was used for the autofluoresence-free cell imaging and labeling. Therefore, our strategy verified that UCNPs could efficiently activate RAFT polymerization by NIR photoirradiation and construct the complex nanohybrids, exhibiting prospective biomedical applications due to the low phototoxicity and deep penetration of NIR light.

  17. 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

  18. Hemodynamic Response to Interictal Epileptiform Discharges Addressed by Personalized EEG-fNIRS Recordings

    Science.gov (United States)

    Pellegrino, Giovanni; Machado, Alexis; von Ellenrieder, Nicolas; Watanabe, Satsuki; Hall, Jeffery A.; Lina, Jean-Marc; Kobayashi, Eliane; Grova, Christophe

    2016-01-01

    Objective: We aimed at studying the hemodynamic response (HR) to Interictal Epileptic Discharges (IEDs) using patient-specific and prolonged simultaneous ElectroEncephaloGraphy (EEG) and functional Near InfraRed Spectroscopy (fNIRS) recordings. Methods: The epileptic generator was localized using Magnetoencephalography source imaging. fNIRS montage was tailored for each patient, using an algorithm to optimize the sensitivity to the epileptic generator. Optodes were glued using collodion to achieve prolonged acquisition with high quality signal. fNIRS data analysis was handled with no a priori constraint on HR time course, averaging fNIRS signals to similar IEDs. Cluster-permutation analysis was performed on 3D reconstructed fNIRS data to identify significant spatio-temporal HR clusters. Standard (GLM with fixed HRF) and cluster-permutation EEG-fMRI analyses were performed for comparison purposes. Results: fNIRS detected HR to IEDs for 8/9 patients. It mainly consisted oxy-hemoglobin increases (seven patients), followed by oxy-hemoglobin decreases (six patients). HR was lateralized in six patients and lasted from 8.5 to 30 s. Standard EEG-fMRI analysis detected an HR in 4/9 patients (4/9 without enough IEDs, 1/9 unreliable result). The cluster-permutation EEG-fMRI analysis restricted to the region investigated by fNIRS showed additional strong and non-canonical BOLD responses starting earlier than the IEDs and lasting up to 30 s. Conclusions: (i) EEG-fNIRS is suitable to detect the HR to IEDs and can outperform EEG-fMRI because of prolonged recordings and greater chance to detect IEDs; (ii) cluster-permutation analysis unveils additional HR features underestimated when imposing a canonical HR function (iii) the HR is often bilateral and lasts up to 30 s. PMID:27047325

  19. Hemodynamic response to Interictal Epileptiform Discharges addressed by personalized EEG-fNIRS recordings

    Directory of Open Access Journals (Sweden)

    Giovanni ePellegrino

    2016-03-01

    Full Text Available Objective: We aimed at studying the hemodynamic response (HR to Interictal Epileptic Discharges (IEDs using patient-specific and prolonged simultaneous ElectroEncephaloGraphy (EEG and functional Near InfraRed Spectroscopy (fNIRS recordings. Methods: The epileptic generator was localized using Magnetoencephalography source imaging. fNIRS montage was tailored for each patient, using an algorithm to optimize the sensitivity to the epileptic generator. Optodes were glued using collodion to achieve prolonged acquisition with high quality signal. fNIRS data analysis was handled with no a priori constraint on HR time course, averaging fNIRS signals to similar IEDs. Cluster-permutation analysis was performed on 3D reconstructed fNIRS data to identify significant spatio-temporal HR clusters. Standard (GLM with fixed HRF and cluster-permutation EEG-fMRI analyses were performed for comparison purposes. Results: fNIRS detected HR to IEDs for 8/9 patients. It mainly consisted oxy-hemoglobin increases (7 patients, followed by oxy-hemoglobin decreases (6 patients. HR was lateralized in 6 patients and lasted from 8.5 to 30s. Standard EEG-fMRI analysis detected an HR in 4/9 patients (4/9 without enough IEDs, 1/9 unreliable result. The cluster-permutation EEG-fMRI analysis restricted to the region investigated by fNIRS showed additional strong and non-canonical BOLD responses starting earlier than the IEDs and lasting up to 30s. Conclusions: i EEG-fNIRS is suitable to detect the HR to IEDs and can outperform EEG-fMRI because of prolonged recordings and greater chance to detect IEDs; ii cluster-permutation analysis unveils additional HR features underestimated when imposing a canonical HR function iii the HR is often bilateral and lasts up to 30s.

  20. 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

  1. 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

  2. Plasma luminescence feedback control system for precise ultrashort pulse laser tissue ablation

    Science.gov (United States)

    Kim, Beop-Min; Feit, Michael D.; Rubenchik, Alexander M.; Gold, David M.; Darrow, Christopher B.; Marion, John E., II; Da Silva, Luiz B.

    1998-05-01

    Plasma luminescence spectroscopy was used for precise ablation of bone tissue without damaging nearby soft tissue using an ultrashort pulse laser. Strong contrast of the luminescence spectra between bone marrow and spinal cord provided the real time feedback control so bone tissue is selectively ablated while preserving the spinal cord.

  3. Luminescence properties of Si-containing porous matrix–PbS nanoparticle systems

    International Nuclear Information System (INIS)

    Tarasov, S. A.; Aleksandrova, O. A.; Lamkin, I. A.; Maksimov, A. I.; Maraeva, E. V.; Mikhailov, I. I.; Moshnikov, V. A.; Musikhin, S. F.; Nalimova, S. S.; Permyakov, N. V.; Spivak, Yu. M.; Travkin, P. G.

    2015-01-01

    The luminescence properties of systems that contain lead-sulfide nanoparticles deposited onto substrates fabricated from porous silicon, oxidized porous silicon, and porous (tin-oxide)–(silicon-oxide) layers are studied. It is shown that the structure and composition of the matrix induce a strong effect on the luminescence spectra of colloidal quantum dots, defining their emission wavelength

  4. 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.

  5. 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.

  6. 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;

  7. Magnetic nanosensor particles in luminescence upconversion capability.

    Science.gov (United States)

    Wilhelm, Stefan; Hirsch, Thomas; Scheucher, Elisabeth; Mayr, Torsten; Wolfbeis, Otto S

    2011-09-05

    Nanoparticles (NPs) exhibit interesting size-dependent electrical, optical, magnetic, and chemical properties that cannot be observed in their bulk counterparts. The synthesis of NPs (i.e., crystalline particles ranging in size from 1 to 100 nm) has been intensely studied in the past decades. Magnetic nanoparticles (MNPs) form a particularly attractive class of NPs and have found numerous applications such as in magnetic resonance imaging to visualize cancer, cardiovascular, neurological and other diseases. Other uses include drug targeting, tissue imaging, magnetic immobilization, hyperthermia, and magnetic resonance imaging. MNPs, due to their magnetic properties, can be easily separated from (often complex) matrices and manipulated by applying external magnetic field. Near-infrared to visible upconversion luminescent nanoparticles (UCLNPs) form another type of unusual nanoparticles. They are capable of emitting visible light upon NIR light excitation. Lanthanide-doped (Yb, Er) hexagonal NaYF₄ UCLNPs are the most efficient upconversion phosphors known up to now. The use of UCLNPs for in vitro imaging of cancer cells and in vivo imaging in tissues has been demonstrated. UCLNPs show great potential as a new class of luminophores for biological, biomedical, and sensor applications. We are reporting here on our first results on the combination of MNP and UCLNP technology within an ongoing project supported by the DFG and the FWF (Austria).

  8. Luminescence resonance energy transfer-based nucleic acid hybridization assay on cellulose paper with upconverting phosphor as donors.

    Science.gov (United States)

    Zhou, Feng; Noor, M Omair; Krull, Ulrich J

    2014-03-04

    A bioassay based on DNA hybridization on cellulose paper is a promising format for gene fragment detection that may be suited for in-field and rapid diagnostic applications. We demonstrate for the first time that luminescence resonance energy transfer (LRET) associated with upconverting phosphors (UCPs) can be used to develop a paper-based DNA hybridization assay with high sensitivity, selectivity and fast response. UCPs with strong green emission were synthesized and subsequently functionalized with streptavidin (UCP-strep). UCP-strep particles were immobilized on cellulose paper, and then biotinylated single-stranded oligonucleotide probes were conjugated onto the UCPs via streptavidin-biotin linkage. The UCPs served as donors that were LRET-paired with Cy3-labeled target DNA. Selective DNA hybridization enabled the proximity required for LRET-sensitized emission from Cy3, which was used as the detection signal. Hybridization was complete within 2 min, and the limit of detection of the method was 34 fmol, which is a significant improvement in comparison to an analogous fluorescence resonance energy transfer (FRET) assay based on quantum dots. The assay exhibited excellent resistance to nonspecific adsorption of noncomplementary short/long DNA and protein. The selectivity of the assay was further evaluated by one base pair mismatched (1BPM) DNA detection, where a maximum signal ratio of 3.1:1 was achieved between fully complementary and 1BPM samples. This work represents a preliminary but significant step for the development of paper-based UCP-LRET nucleic acid hybridization assays, which offer potential for lowering the limit of detection of luminescent hybridization assays due to the negligible background signal associated with optical excitation by near-infrared (NIR) light.

  9. 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

  10. 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.

  11. LUMINESCENCE DETERMINATION OF ETODOLAC

    Directory of Open Access Journals (Sweden)

    A. V. Yegorova

    2015-02-01

    Full Text Available A highly sensitive, simple and rapid method for determination of non-steroidal anti- inflammatory drug – etodolac (Et in washings from surfaces of pharmaceutical equipment have been proposed. The intensity of native luminescence of water-n-propanol solutions of etodolac (λex= 274 nm; λlum= 350 nm was used as the analytical signal. The calibration graph is linear in the concentration range 0.014-2.3 μg/ml, the limit of detection is 0.5 ng/ml.

  12. NIR: optimerer produktionen af gammeldags modnede sild

    DEFF Research Database (Denmark)

    Svensson, T.; Bro, Rasmus; Nielsen, Henrik Hauch

    2005-01-01

    Måling med nærinfrarødt (NIR) lys er et godt supplement til de nuværende metoder til at følge modningen af sild saltede i tønder. Det viser resultaterne af et forskningsprojekt udført i samarbejde mellem Lykkeberg A/S, Danmarks Fiskeriundersøgelser og Den Kgl Veterinær- og Landbohøjskole. Ved hjælp...... af avanceret matematik er det nemt og hurtigt at bestemme modningsgraden af sild direkte fra en NIR måling....

  13. Water soluble (Ln3+) doped nanoparticle: Retention of strong luminescence

    Science.gov (United States)

    Attar, Tarannum Vahid; Khandpekar, Mahendra M.

    2018-04-01

    This paper deals with the synthesis of hexagonal nanoparticles of LaF3: Nd, Ho (LFNH) in the presence of LaCl3.7H2O and NH4F by precipitation method using deionized water as solvent. The nanoparticles have a nearly hexagonal shape with cell parameters, a = b = 7.0980 AU and c = 7.2300 AU and confirms with the JCPDS standard card (32-0483) of pure LaF3 crystals. The TEM results show that the average sizes of these nanoparticles are 15nm which is consistent with the sizes obtained from XRD measurements. The SEM image shows uniform size distribution of the nanoparticles. Detection of Second harmonic generation (SHG) signal together with the presence of wide transparency window (UV studies) makes LFNH suitable for optoelectronic applications. The Photoluminescence of the nanocrystals has been observed by excitation and emission spectra. The peak at 629nm indicates red up conversion fluorescence useful in applications like bioimaging and biolabelling.

  14. 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.

  15. 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.

  16. 2D Vis/NIR correlation spectroscopy of cooked chicken meats

    Science.gov (United States)

    Liu, Yongliang; Chen, Yud-Ren; Ozaki, Yukihiro

    2000-03-01

    Cooking of chicken meats was investigated by the generalized two-dimensional visible/near-infrared (2D Vis/NIR) correlation spectroscopy. Synchronous and asynchronous spectra in the 400-700 nm visible region suggested that the 445 and 560 nm bands be ascribed to deoxymyoglobin and oxymyoglobin, and at least one of the 475, 520, and 585 nm bands is assignable to the denatured species (metmyoglobin). The asynchronous 2D NIR correlation spectrum showed that CH bands change their spectral intensities before the OH/NH groups during the cooking process, indicating that CH fractions are easily oxidized and degraded. In addition, strong correlation peaks were observed correlating the bands in the visible and NIR spectral regions.

  17. Luminescence dating in archaeology

    International Nuclear Information System (INIS)

    Wintle, A.G.

    2001-01-01

    Thermoluminescence (TL) dating is routinely applied to burnt lithic material. Simple fires are capable of enabling stones weighing a few hundred grams to reach 450 o C, thus zeroing the TL signal. TL dates have been obtained for Upper and Lower Paleolithic sites in Europe and the Near East. TL dating continues to be used for dating pottery and for authentification of ceramic works of art. Some recent studies report the use of optically stimulated luminescence (OSL) (also know as photoluminescence) for dating very small samples of quartz, e.g. from small pieces of pottery or frm metallurgical slag The major recent advance has been in the development of a reliable laboratory procedure for using the OSL signal from quartz to obtain the past radiation exposure. The quartz OSL signal is extremely sensitive to light and is reduced to a negligible level on exposure to direct sunlight for radionuclides during burial, signal to date san.sized quartz grains extracted from sediments, The OSL signal is stimulated by 470 nm light from emitting diodes and the detected using flirters centred on 340 nm A similar signal can be obtained from feldspar grain when are exposed to infrared wavelengths around 880 nm. The infrared stimulated luminescence (IRSL) signals is also rapidly depleted by exposure to sunlight, and dating of colluvial deposits from archaeological sites has been reported

  18. Monitoring of whey quality with NIR spectroscopy

    DEFF Research Database (Denmark)

    Kucheryavskiy, Sergey; Lomborg, Carina

    2015-01-01

    The possibility of using near-infrared (NIR) spectroscopy for monitoring of liquid whey quality parameters during protein production process has been tested. The parameters included total solids, lactose, protein and fat content. The samples for the experiment were taken from real industrial...

  19. Experimental radiation carcinogenesis is studies at NIRS

    International Nuclear Information System (INIS)

    Sado, Toshihiko

    1992-01-01

    Experimental radiation carcinogenesis studies conducted during the past decade at NIRS are briefly reviewed. They include the following: 1) Age dependency of susceptibility to radiation carcinogenesis. 2) Radiation-induced myeloid leukemia. 3) Mechanism of fractionated X-irradiation (FX) induced thymic lymphomas. 4) Significance of radiation-induced immunosuppression in radiation carcinogenesis in vivo. 5) Other ongoing studies. (author)

  20. Near Infrared-Emitting Cr3+/Eu3+ Co-doped Zinc Gallogermanate Persistence Luminescent Nanoparticles for Cell Imaging

    Science.gov (United States)

    Wang, Qiaoqiao; Zhang, Shuyun; Li, Zhiwei; Zhu, Qi

    2018-02-01

    Near infrared (NIR)-emitting persistent luminescent nanoparticles have been developed as potential agents for bioimaging. However, synthesizing uniform nanoparticles with long afterglow for long-term imaging is lacking. Here, we demonstrated the synthesis of spinel structured Zn3Ga2Ge2O10:Cr3+ (ZGGO:Cr3+) and Zn3Ga2Ge2O10:Cr3+,Eu3+ (ZGGO:Cr3+,Eu3+) nanoparticles by a sol-gel method in combination with a subsequent reducing atmosphere-free calcination. The samples were investigated via detailed characterizations by combined techniques of XRD, TEM, STEM, selected area electron diffraction, photoluminescence excitation (PLE)/photoluminescence (PL) spectroscopy, and temperature-dependent PL analysis. The single-crystalline nanoparticles are homogeneous solid solution, possessing uniform cubic shape and lateral size of 80-100 nm. Upon UV excitation at 273 nm, ZGGO:Cr3+,Eu3+ exhibited a NIR emission band at 697 nm (2E → 4A2 transition of distorted Cr3+ ions in gallogermanate), in the absence of Eu3+ emission. NIR persistent luminescence of the sample can last longer than 7200 s and still hold intense intensity. Eu3+ incorporation increased the persistent luminescence intensity and the afterglow time of ZGGO:Cr3+, but it did not significantly affect the thermal stability. The obtained ZGGO:Cr3+,Eu3+-NH2 nanoparticles possessed an excellent imaging capacity for cells in vitro.

  1. Anti-Stokes Luminescence in High Quality Quantum Wells

    Science.gov (United States)

    Vinattieri, A.; Bogani, F.; Miotto, A.; Ceccherini, S.

    1997-11-01

    We present a detailed investigation of the anti-Stokes (AS) luminescence which originates from exciton recombination when below gap excitation is used, in a set of high quality quantum well structures. We observe strong excitonic resonances in the AS signal as measured from photoluminescence and photoluminescence excitation spectra. We demonstrate that neither the electromagnetic coupling between the wells nor the morphological disorder can explain this up-conversion effect. Time-resolved luminescence data after ps excitation and fs correlation spectroscopy results provide clear evidence of the occurrence of a two-step absorption which is assisted by the exciton population resonantly excited by the first photon.

  2. Template-free synthesis and luminescent properties of hollow Ln:YOF (Ln = Eu or Er + Yb) microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Martinez-Castro, E. [Instituto de Ciencia de Materiales de Sevilla (CSIC-US), Americo Vespucio 49, Isla de La Cartuja, 41092 Sevilla (Spain); García-Sevillano, J.; Cussó, F. [Dpto. Física de Materiales, C-04, Universidad Autónoma de Madrid, Avda. Francisco Tomás y Valiente, 7, 28049 Madrid (Spain); Ocaña, M., E-mail: mjurado@icmse.csic.es [Instituto de Ciencia de Materiales de Sevilla (CSIC-US), Americo Vespucio 49, Isla de La Cartuja, 41092 Sevilla (Spain)

    2015-01-15

    Highlights: • Hollow lanthanide doped YOF spheres have been synthesised through a template-free procedure. • Strong red emissions are observed for Eu-doped spheres under UV illumination. • Concentration quenching of luminescence takes place in the spheres at very high Eu doping levels. • Bright red emission is observed for Er, Yb codoped spheres, making this matrix advantageous for biomedical imaging. - Abstract: A method for the synthesis of hollow lanthanide doped yttrium oxyfluoride (YOF) spheres in the micrometer size range with cubic structure based on the pyrolysis at 600 °C of liquid aerosols generated from aqueous solutions containing the corresponding rare earth chlorides and trifluoroacetic acid has been developed. This procedure, which has been used for the first time for the synthesis of YFO based materials, is simpler and advantageous when compared with other methods usually employed for the production of hollow spheres since it does not require the use of sacrificial templates. In addition, it is continuous, which is desirable because of practical reasons. The procedure is also suitable for doping the YOF spheres with europium cations resulting in down converting red phosphors when activated with UV light, or for co-doping with both Er{sup 3+} and Yb{sup 3+} giving rise to up-converting phosphors, which emit intense red light under near infrared (NIR) irradiation. Because of their optical properties and hollow architecture, the developed materials may find applications in optoelectronic devices and biotechnology.

  3. Thermo-luminescent dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Reither, M; Schorn, B; Schneider, E

    1981-01-01

    The development of paediatric radiology which began in the late 195O's has been characterised by the need to limit the dose of ionising radiation to which the child is subjected. The aim has been to keep radiation exposure as low as possible by the introduction of suitable techniques and by the development of new methods. It is therefore surprising that studies in dosimetry in the paediaytric age range have only been carried out in recent years. One reason for this may have been the fact that a suitable technique of measurement was not available at the time. The introduction of solid state dosimetry based on thermo-luminescence, first into radiotherapy (1968) and subsequently into radiodiagnosis, has made it possible to abandon the previously widely used ionisation chamber. The purpose of the present paper is to indicate the suitability of this form of dose measurement for paediatric radiological purposes and to stimulate its application in this field.

  4. 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.

  5. 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

  6. 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.

  7. 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)

  8. Cytochrome cd1-containing nitrite reductase encoding gene nirS as a new functional biomarker for detection of anaerobic ammonium oxidizing (Anammox) bacteria.

    Science.gov (United States)

    Li, Meng; Ford, Tim; Li, Xiaoyan; Gu, Ji-Dong

    2011-04-15

    A newly designed primer set (AnnirS), together with a previously published primer set (ScnirS), was used to detect anammox bacterial nirS genes from sediments collected from three marine environments. Phylogenetic analysis demonstrated that all retrieved sequences were clearly different from typical denitrifiers' nirS, but do group together with the known anammox bacterial nirS. Sequences targeted by ScnirS are closely related to Scalindua nirS genes recovered from the Peruvian oxygen minimum zone (OMZ), whereas sequences targeted by AnnirS are more closely affiliated with the nirS of Candidatus 'Kuenenia stuttgartiensis' and even form a new phylogenetic nirS clade, which might be related to other genera of the anammox bacteria. Analysis demonstrated that retrieved sequences had higher sequence identities (>60%) with known anammox bacterial nirS genes than with denitrifiers' nirS, on both nucleotide and amino acid levels. Compared to the 16S rRNA and hydrazine oxidoreductase (hzo) genes, the anammox bacterial nirS not only showed consistent phylogenetic relationships but also demonstrated more reliable quantification of anammox bacteria because of the single copy of the nirS gene in the anammox bacterial genome and the specificity of PCR primers for different genera of anammox bacteria, thus providing a suitable functional biomarker for investigation of anammox bacteria.

  9. Upconverting and NIR emitting rare earth based nanostructures for NIR-bioimaging

    Science.gov (United States)

    Hemmer, Eva; Venkatachalam, Nallusamy; Hyodo, Hiroshi; Hattori, Akito; Ebina, Yoshie; Kishimoto, Hidehiro; Soga, Kohei

    2013-11-01

    In recent years, significant progress was achieved in the field of nanomedicine and bioimaging, but the development of new biomarkers for reliable detection of diseases at an early stage, molecular imaging, targeting and therapy remains crucial. The disadvantages of commonly used organic dyes include photobleaching, autofluorescence, phototoxicity and scattering when UV (ultraviolet) or visible light is used for excitation. The limited penetration depth of the excitation light and the visible emission into and from the biological tissue is a further drawback with regard to in vivo bioimaging. Lanthanide containing inorganic nanostructures emitting in the near-infrared (NIR) range under NIR excitation may overcome those problems. Due to the outstanding optical and magnetic properties of lanthanide ions (Ln3+), nanoscopic host materials doped with Ln3+, e.g. Y2O3:Er3+,Yb3+, are promising candidates for NIR-NIR bioimaging. Ln3+-doped gadolinium-based inorganic nanostructures, such as Gd2O3:Er3+,Yb3+, have a high potential as opto-magnetic markers allowing the combination of time-resolved optical imaging and magnetic resonance imaging (MRI) of high spatial resolution. Recent progress in our research on over-1000 nm NIR fluorescent nanoprobes for in vivo NIR-NIR bioimaging will be discussed in this review.In recent years, significant progress was achieved in the field of nanomedicine and bioimaging, but the development of new biomarkers for reliable detection of diseases at an early stage, molecular imaging, targeting and therapy remains crucial. The disadvantages of commonly used organic dyes include photobleaching, autofluorescence, phototoxicity and scattering when UV (ultraviolet) or visible light is used for excitation. The limited penetration depth of the excitation light and the visible emission into and from the biological tissue is a further drawback with regard to in vivo bioimaging. Lanthanide containing inorganic nanostructures emitting in the near

  10. Radioecological studies in early period of NIRS

    International Nuclear Information System (INIS)

    Ichikawa, Ryushi

    2004-01-01

    Japanese tuna-fishing boat Fukuryumaru No.5 was exposed to heavy radioactive fallout due to the nuclear test explosion carried out by U.S.A. at Bikini Atoll of Marshal Islands in the central part of Pacific Ocean on March 1, 1954. Following this accident, radioactivity was detected in various environmental samples including rain, marine fishes and agricultural crops. Science Council of Japan organized the new research group of many scientists in the field of fisheries, agricultural, medical and biological studies and radiation protection studies. Government of Japan established National Institute of Radiological Sciences (NIRS) in 1957. In this Institute various radioecological studies have been carried out. In this paper, some of these radioecological studies carried out in early period of NIRS are described. (author)

  11. NIR spectroscopic properties of aqueous acids solutions.

    Science.gov (United States)

    Omar, Ahmad Fairuz; Atan, Hanafi; Matjafri, Mohd Zubir

    2012-06-15

    Acid content is one of the important quality attributes in determining the maturity index of agricultural product, particularly fruits. Despite the fact that much research on the measurement of acidity in fruits through non-destructive spectroscopy analysis at NIR wavelengths between 700 to 1,000 nm has been conducted, the same response towards individual acids is not well known. This paper presents NIR spectroscopy analysis on aqueous citric, tartaric, malic and oxalic solutions through quantitative analysis by selecting a set of wavelengths that can best be used to measure the pH of the solutions. The aquaphotomics study of the acid solutions has generated R² above 0.9 for the measurement of all acids. The most important wavelengths for pH are located at 918-925 nm and 990-996 nm, while at 975 nm for water.

  12. Agricultural applications of NIR reflectance and transmittance

    DEFF Research Database (Denmark)

    Gislum, René

    2009-01-01

    There has been a considerable increase in the use of near infrared (NIR) reflectance and transmittance spectroscopy technologies for rapid determination of quality parameters in agriculture, including applications within crop product quality, feed and food quality, manure quality, soil analyses etc....... As a result it was decided to arrange a seminar within the Nordic Association of Agricultural Scientists. This is a report of the meeting....

  13. Design and construction of a NIR spectrometer

    CERN Document Server

    Barcala-Riveira, J M; Fernandez-Marron, J L; Molero-Menendez, F; Navarrete-Marin, J J; Oller-Gonzalez, J C

    2003-01-01

    This document describes the design and construction of a NIR spectrometer based on an acoustic-optic tunable filter. The spectrometer will be used for automatic identification of plastics in domestic waste. The system works between 1200 and 1800 nm. Instrument is controlled by a personal computer. Computer receives and analyses data. A software package has been developed to do these tasks. (Author) 27 refs.

  14. NIRS database of the original research database

    International Nuclear Information System (INIS)

    Morita, Kyoko

    1991-01-01

    Recently, library staffs arranged and compiled the original research papers that have been written by researchers for 33 years since National Institute of Radiological Sciences (NIRS) established. This papers describes how the internal database of original research papers has been created. This is a small sample of hand-made database. This has been cumulating by staffs who have any knowledge about computer machine or computer programming. (author)

  15. Design and construction of a NIR spectrometer

    International Nuclear Information System (INIS)

    Barcala Riveira, J. M.; Fernandez Marron, J. L.; Alberdi Primicia, J.; Molero Menendez, F.; Navarrete Marin, J. J.; Oller Gonzalez, J. C.

    2003-01-01

    This document describes the design and construction of a NIR spectrometer based on an acoustic-optic tunable filter. The spectrometer will be used for automatic identification of plastics in domestic waste. The system works between 1200 and 1800 nm. Instrument is controlled by a personal computer. Computer receives and analyses data. A software package has been developed to do these tasks. (Author) 27 refs

  16. Spectroscopic investigation on europium doped heavy metal borate glasses for red luminescent application

    Energy Technology Data Exchange (ETDEWEB)

    Hegde, Vinod; Wagh, Akshatha; Kamath, Sudha D. [Manipal University, Department of Physics, Manipal Institute of Technology, Manipal (India); Hegde, Hemanth [Manipal University, Department of Chemistry, Manipal Institute of Technology, Manipal (India); Vishwanath, C.S.D. [Sri Venkateswara University, Department of Physics, Tirupati (India)

    2017-05-15

    The present study explores a new borate family glasses based on 10ZnO-5Na{sub 2}O-10Bi{sub 2}O{sub 3}-(75 - x) B{sub 2}O{sub 3}-xEu{sub 2}O{sub 3} (x = 0, 0.1, 0.5, 1, 1.5, 2, 3 mol%) composition, synthesized by rapid melt quench technique. Prepared glasses were subjected to the density and refractive index measurements and their values were used to calculate other physical properties of the glass matrix as a function of Eu{sup 3+} concentration. XRD confirmed amorphous nature of the glasses. FTIR spectra in the absorption mode were recorded in the 400-4000 cm{sup -1} region to identify different functional groups in the glass matrix. Deconvoluted FTIR spectra showed increase in BO{sub 4} units with rise in europium content which confirmed the 'network strengthener' role of europium ions by creating bridging oxygens (BOs). Optical properties were investigated for their luminescence behavior through various spectroscopic techniques such as UV-Vis-NIR absorption, excitation, emission, decay profiles, and color measurements at room temperature. Lasing properties of the glasses like total radiative life time, branching ratio, emission cross section, and optical gain were obtained from the calculated Judd-Ofelt (Ω{sub 2},Ω{sub 4}) intensity parameters. From the measured values of emission, cross sections, branching ratios, life times, strong photoluminescence features, and CIE chromaticity coordinates, 0.5 mol% of Eu{sup 3+} ions doped ZnNaBiB glasses showed optimum performance and are potential candidate for red light generation at 613 nm. (orig.)

  17. Towards NIRS-based hand movement recognition.

    Science.gov (United States)

    Paleari, Marco; Luciani, Riccardo; Ariano, Paolo

    2017-07-01

    This work reports on preliminary results about on hand movement recognition with Near InfraRed Spectroscopy (NIRS) and surface ElectroMyoGraphy (sEMG). Either basing on physical contact (touchscreens, data-gloves, etc.), vision techniques (Microsoft Kinect, Sony PlayStation Move, etc.), or other modalities, hand movement recognition is a pervasive function in today environment and it is at the base of many gaming, social, and medical applications. Albeit, in recent years, the use of muscle information extracted by sEMG has spread out from the medical applications to contaminate the consumer world, this technique still falls short when dealing with movements of the hand. We tested NIRS as a technique to get another point of view on the muscle phenomena and proved that, within a specific movements selection, NIRS can be used to recognize movements and return information regarding muscles at different depths. Furthermore, we propose here three different multimodal movement recognition approaches and compare their performances.

  18. Distraction decreases prefrontal oxygenation: A NIRS study.

    Science.gov (United States)

    Ozawa, Sachiyo; Hiraki, Kazuo

    2017-04-01

    When near-infrared spectroscopy (NIRS) is used to measure emotion-related cerebral blood flow (CBF) changes in the prefrontal cortex regions, the functional distinction of CBF changes is often difficult because NIRS is unable to measure neural activity in deeper brain regions that play major roles in emotional processing. The CBF changes could represent cognitive control of emotion and emotional responses to emotional materials. Supposing that emotion-related CBF changes in the prefrontal cortex regions during distraction are emotional responses, we examined whether oxygenated hemoglobin (oxyHb) decreases. Attention-demanding tasks cause blood flow decreases, and we thus compared the effects of visually paced tapping with different tempos, on distraction. The results showed that the oxyHb level induced by emotional stimulation decreased with fast-tempo tapping significantly more than slow-tempo tapping in ventral medial prefrontal cortex regions. Moreover, a Global-Local task following tapping showed significantly greater local-minus-global response time (RT) difference scores in the fast- and mid-tempo condition compared with those in the slow-tempo, suggesting an increased attentional focus, and decreased negative emotion. The overall findings indicate that oxyHb changes in a relatively long distraction task, as measured by NIRS, are associated with emotional responses, and oxyHb can be decreased by successfully performing attention-demanding distraction tasks. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Remote Estimation of Chlorophyll-a in Inland Waters by a NIR-Red-Based Algorithm: Validation in Asian Lakes

    Directory of Open Access Journals (Sweden)

    Gongliang Yu

    2014-04-01

    Full Text Available Satellite remote sensing is a highly useful tool for monitoring chlorophyll-a concentration (Chl-a in water bodies. Remote sensing algorithms based on near-infrared-red (NIR-red wavelengths have demonstrated great potential for retrieving Chl-a in inland waters. This study tested the performance of a recently developed NIR-red based algorithm, SAMO-LUT (Semi-Analytical Model Optimizing and Look-Up Tables, using an extensive dataset collected from five Asian lakes. Results demonstrated that Chl-a retrieved by the SAMO-LUT algorithm was strongly correlated with measured Chl-a (R2 = 0.94, and the root-mean-square error (RMSE and normalized root-mean-square error (NRMS were 8.9 mg∙m−3 and 72.6%, respectively. However, the SAMO-LUT algorithm yielded large errors for sites where Chl-a was less than 10 mg∙m−3 (RMSE = 1.8 mg∙m−3 and NRMS = 217.9%. This was because differences in water-leaving radiances at the NIR-red wavelengths (i.e., 665 nm, 705 nm and 754 nm used in the SAMO-LUT were too small due to low concentrations of water constituents. Using a blue-green algorithm (OC4E instead of the SAMO-LUT for the waters with low constituent concentrations would have reduced the RMSE and NRMS to 1.0 mg∙m−3 and 16.0%, respectively. This indicates (1 the NIR-red algorithm does not work well when water constituent concentrations are relatively low; (2 different algorithms should be used in light of water constituent concentration; and thus (3 it is necessary to develop a classification method for selecting the appropriate algorithm.

  20. 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.

  1. Pharmaceutical applications using NIR technology in the cloud

    Science.gov (United States)

    Grossmann, Luiz; Borges, Marco A.

    2017-05-01

    NIR technology has been available for a long time, certainly more than 50 years. Without any doubt, it has found many niche applications, especially in the pharmaceutical, food, agriculture and other industries due to its flexibility. There are a number of advantages over other existing analytical technologies we can list, for example virtually no need for sample preparation; usually NIR does not demand sample destruction and subsequent discard; NIR provides fast results; NIR does not require extensive operator training and carries small operating costs. However, the key point about NIR technology is the fact that it's more related to statistics than chemistry or, in other words, we are more concerned about analyzing and distinguishing features within the data than looking deep into the chemical entities themselves. A simple scan reading in the NIR range usually involves huge inflows of data points. Usually we decompose the signals into hundreds of predictor variables and use complex algorithms to predict classes or quantify specific content. NIR is all about math, especially by converting chemical information into numbers. Easier said than done. A NIR signal is a very complex one. Usually the signal responses are not specific to a particular material, rather, each grouṕs responses add up, thus providing low specificity of a spectral reading. This paper proposes a simple and efficient method to analyze and compare NIR spectra for the purpose of identifying the presence of active pharmaceutical ingredients in finished products using low cost NIR scanning devices connected to the internet cloud.

  2. Goldenphilicity: Luminescent gold compounds

    International Nuclear Information System (INIS)

    Sansores, L.E.

    2002-01-01

    In the solids and molecules different types of bonds are presented depending on the involved atoms, covalent bonds are common among elements of open shell, where more bond orbitals are filled than anti bond orbitals. It is expected that ionic bonds among closed shell atoms which have charges of opposite sign. Bonds type Van der Waals are presented among molecules which have a bipolar moment. It would not be expected bonds among zero charge species, or more generally with the same nominal charge and in any case the attractive forces would be very small. In fact it is expected that two metallic cations to be repelled each other. There recently is evidence that in organic or organometallic compounds could exist attractive interactions between two cations of the d 8 -d 10 -s 2 families. These bonds are weak but stronger than those of Van der Waals. They are compared with the hydrogen bonds. In this work it was reviewed some examples in which the goldenphilicity plays an important role in the luminescence that the gold complexes present. Examples of mono, bi and trinuclear and the structures that these organometallic compounds could take are examined. (Author)

  3. 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)

  4. 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...

  5. 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.

  6. <strong>Mini-project>

    DEFF Research Database (Denmark)

    Katajainen, Jyrki

    2008-01-01

    In this project the goal is to develop the safe * family of containers for the CPH STL. The containers to be developed should be safer and more reliable than any of the existing implementations. A special focus should be put on strong exception safety since none of the existing prototypes available...

  7. Luminescent lanthanide coordination polymers

    Energy Technology Data Exchange (ETDEWEB)

    Ma, L.; Evans, O.R.; Foxman, B.M.; Lin, W.

    1999-12-13

    One-dimensional lanthanide coordination polymers with the formula Ln(isonicotinate){sub 3}(H{sub 2}O){sub 2} (Ln = Ce, Pr, Nd, Sm, Eu, Tb; 1a-f) were synthesized by treating nitrate or perchlorate salts of Ln(III) with 4-pyridinecarboxaldehyde under hydro(solvo)thermal conditions. Single-crystal and powder X-ray diffraction studies indicate that these lanthanide coordination polymers adopt two different structures. While Ce(III), Pr(III), and Nd(III) complexes adopt a chain structure with alternating Ln-(carboxylate){sub 2}-Ln and Ln-(carboxylate){sub 4}-Ln linkages, Sm(III), Eu(III), and Tb(III) complexes have a doubly carboxylate-bridged infinite-chain structure with one chelating carboxylate group on each metal center. In both structures, the lanthanide centers also bind to two water molecules to yield an eight-coordinate, square antiprismatic geometry. The pyridine nitrogen atoms of the isonicotinate groups do not coordinate to the metal centers in these lanthanide(III) complexes; instead, they direct the formation of Ln(III) coordination polymers via hydrogen bonding with coordinated water molecules. Photoluminescence measurements show that Tb(isonicotinate){sub 3}(H{sub 2}O){sub 2} is highly emissive at room temperature with a quantum yield of {approximately}90%. These results indicate that highly luminescent lanthanide coordination polymers can be assembled using a combination of coordination and hydrogen bonds. Crystal data for 1a: monoclinic space group P2{sub 1}/c, a = 9.712(2) {angstrom}, b = 19.833(4) {angstrom}, c = 11.616(2) {angstrom}, {beta} = 111.89(3){degree}, Z = 4. Crystal data for 1f: monoclinic space group C2/c, a = 20.253(4) {angstrom}, b = 11.584(2) {angstrom}, c = 9.839(2) {angstrom}, {beta} = 115.64(3){degree}, Z = 8.

  8. Strong interactions

    International Nuclear Information System (INIS)

    Froissart, Marcel

    1976-01-01

    Strong interactions are introduced by their more obvious aspect: nuclear forces. In hadron family, the nucleon octet, OMEGA - decuplet, and quark triply are successively considered. Pion wave having been put at the origin of nuclear forces, low energy phenomena are described, the force being explained as an exchange of structure corresponding to a Regge trajectory in a variable rotating state instead of the exchange of a well defined particle. At high energies the concepts of pomeron, parton and stratons are introduced, pionization and fragmentation are briefly differentiated [fr

  9. 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

  10. 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

  11. 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.

  12. 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.

  13. Luminescence and structural study of porous silicon films

    Science.gov (United States)

    Xie, Y. H.; Wilson, W. L.; Ross, F. M.; Mucha, J. A.; Fitzgerald, E. A.; Macaulay, J. M.; Harris, T. D.

    1992-03-01

    A combination of photoluminescence, TEM, and Fourier transform IR spectroscopy is used to investigate the luminescence properties of 3-micron thick, strongly emitting, and highly porous silicon films. TEMs indicate that these samples have structures of predominantly 6-7-nm size clusters. In the as-prepared films, there is a significant concentration of Si-H bonds which is gradually replaced by Si-O bonds during prolonged aging in air. Upon optical excitation these films exhibit strong visible emission, peaking at about 690 nm. The excitation edge is shown to be emission-wavelength dependent, revealing the inhomogeneous nature of both the initially photoexcited and luminescing species. The correlation of the spectral and structural information suggest that the source of the large blue shift of the visible emission compared to the bulk Si bandgap energy is due to quantum confinement in the nanometer-size Si clusters.

  14. Toxicity Evaluation of Pig Slurry Using Luminescent Bacteria and Zebrafish

    Directory of Open Access Journals (Sweden)

    Wenyan Chen

    2014-07-01

    Full Text Available Biogas slurry has become a serious pollution problem and anaerobic digestion is widely applied to pig manure treatment for environmental protection and energy recovery. To evaluate environmental risk of the emission of biogas slurry, luminescent bacteria (Vibrio fischeri, larvae and embryos of zebrafish (Danio rerio were used to detect the acute and development toxicity of digested and post-treated slurry. Then the ability of treatment process was evaluated. The results showed that digested slurry displayed strong toxicity to both zebrafish and luminescent bacteria, while the EC50 for luminescent bacteria and the LC50 for larvae were only 6.81% (v/v and 1.95% (v/v respectively, and embryonic development was inhibited at just 1% (v/v. Slurry still maintained a high level of toxicity although it had been treated by membrane bioreactor (MBR, while the LC50 of larvae was 75.23% (v/v and there was a little effect on the development of embryos and V. fischeri; the results also revealed that the zebrafish larvae are more sensitive than embryos and luminescent bacteria to pig slurry. Finally, we also found the toxicity removal rate was higher than 90% after the treatment of MBR according to toxicity tests. In conclusion, further treatment should be used in pig slurry disposal or reused of final effluent.

  15. New laser design for NIR lidar applications

    Science.gov (United States)

    Vogelmann, H.; Trickl, T.; Perfahl, M.; Biggel, S.

    2018-04-01

    Recently, we quantified the very high spatio-temporal short term variability of tropospheric water vapor in a three dimensional study [1]. From a technical point of view this also depicted the general requirement of short integration times for recording water-vapor profiles with lidar. For this purpose, the only suitable technique is the differential absorption lidar (DIAL) working in the near-infrared (NIR) spectral region. The laser emission of most water vapor DIAL systems is generated by Ti:sapphire or alexandrite lasers. The water vapor absorption band at 817 nm is predominated for the use of Ti:sapphire. We present a new concept of transversely pumping in a Ti:Sapphire amplification stage as well as a compact laser design for the generation of single mode NIR pulses with two different DIAL wavelengths inside a single resonator. This laser concept allows for high output power due to repetitions rates up to 100Hz or even more. It is, because of its compactness, also suitable for mobile applications.

  16. 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.

  17. Hydrothermal synthesis, characterization and luminescent ...

    Indian Academy of Sciences (India)

    that nanoparticles have cylindrical shape and crystalline nature of nanoparticles was confirmed by SAED patterns. Down- conversion (DC) luminescent properties of doped NaLaF4 were also .... Figure 1 shows the XRPD patterns of undoped NaLaF4 and .... which can be assigned to the transitions from the 7F6 ground.

  18. A portable luminescence dating instrument

    DEFF Research Database (Denmark)

    Kook, M.H.; Murray, A.S.; Lapp, Torben

    2011-01-01

    We describe a portable luminescence reader suitable for use in remote localities in the field. The instrument weighs about 8kg and is based around a 30mm bialkali photomultiplier detecting signals through a glass filter centered on 340nm. Stimulation is by 470nm blue LEDs (24W in total) operating...

  19. 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...

  20. 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.

  1. 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.

  2. NIRS - Near infrared spectroscopy - investigations in neurovascular diseases

    DEFF Research Database (Denmark)

    Schytz, Henrik Winther

    2015-01-01

    The purpose of this thesis was to explore and develop methods, where continuous wave near infrared spectroscopy (CW-NIRS) can be applied in different neurovascular diseases, in order to find biological markers that are useful in clinical neurology. To develop a new method to detect changes...... tomography (133Xe-SPECT) and the corrected BFI value. It was concluded, that it was not possible to obtain reliable BFI data with the ICG CW-NIRS method. NIRS measurements of low frequency oscillations (LFOs) may be a reliable method to investigate vascular alterations in neurovascular diseases......, but this requires an acceptable LFOs variation between hemispheres and over time in the healthy brain. The second study therefore investigated day-to-day and hemispheric variations in LFOs with NIRS. It was shown that NIRS might be useful in assessing LFOs between hemispheres, as well as interhemispheric phase...

  3. Luminescence detection of phase transitions in crystals and nanoparticle inclusions

    International Nuclear Information System (INIS)

    Townsend, P. D.; Yang, B.; Wang, Y.

    2008-01-01

    Luminescence measurements are extremely sensitive to variations in structural environment and thus have the potential to probe distortions of fluorescence sites. Changes can be monitored via luminescence efficiency, emission spectra or excited state lifetimes and these factors are influenced by the local neighbourhood around the emission site, and therefore by structure, composition, pressure and temperature. A rarely exploited approach for condensed matter has been to use the changes in luminescence responses during heating or cooling of a material to provide a rapid survey to detect the presence of phase transitions. One can often differentiate between bulk and surface effects by contrasting results from radioluminescence for bulk responses, and cathodoluminescence or photoluminescence for surface effects. One expects that discontinuous changes in optical parameters occur during temperature changes through phase transitions of insulating materials. In practice, optical signals also exist from surface states of fullerenes and high temperature superconductors etc which identify the presence of structural or superconducting transitions. Numerous examples are cited which match standard documented transitions. Interestingly many examples show the host signals are strongly sensitive to impurity phase transitions from inclusions such as nanoparticles of water, N 2 , O 2 or CO 2 . Recent luminescence data reveal many examples of new transitions, hysteresis and irreversible changes. The signals equally respond to relaxations of a structure and surprisingly indicate that in some materials, such as SrTiO 3 or ZnO, ion implantation of the surface triggers relaxations and phase changes throughout the bulk of the material. Luminescence routes to detect phase transitions are powerful tools but have a tiny literature and so the subject is ideal for rapid exploitation and development. (Author)

  4. Standardization from a benchtop to a handheld NIR spectrometer using mathematically mixed NIR spectra to determine fuel quality parameters

    DEFF Research Database (Denmark)

    da Silva, Neirivaldo Cavalcante; Cavalcanti, Claudia Jessica; Honorato, Fernanda Araujo

    2017-01-01

    spectral responses of fuel samples (gasoline and biodiesel blends) from a high-resolution benchtop Frontier FT-NIR (PerkinElmer) spectrometer and a handheld MicroNIR™1700 (JDSU). These virtual standards can be created by mathematically mixing spectra from the pure solvents present in gasoline or diesel...... to the handheld MicroNIR using virtual standards as transfer samples...

  5. Diseno y construccion de un espectrometro NIR; Design and construction of a NIR spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Barcala Riveira, J M; Fernandez Marron, J L; Alberdi Primicia, J; Molero Menendez, F; Navarrete Marin, J J; Oller Gonzalez, J C

    2003-07-01

    This document describes the design and construction of a NIR spectrometer based on an acoustic-optic tunable filter. The spectrometer will be used for automatic identification of plastics in domestic waste. The system works between 1200 and 1800 nm. Instrument is controlled by a personal computer. Computer receives and analyses data. A software package has been developed to do these tasks. (Author) 27 refs.

  6. Insights on proximity effect and multiphoton induced luminescence from gold nanospheres in far field optical microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Borglin, Johan [Biomedical Photonics Group, Department of Chemistry and Molecular Biology, University of Gothenburg, Kemivägen 10, 412 96 Gothenburg (Sweden); Department of Physics, University of Gothenburg, Kemivägen 10, 412 96 Gothenburg (Sweden); Guldbrand, Stina [Department of Physics, University of Gothenburg, Kemivägen 10, 412 96 Gothenburg (Sweden); Evenbratt, Hanne [Pharmaceutical Technology, Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Kemigården 4, 412 96 Gothenburg (Sweden); Kirejev, Vladimir; Ericson, Marica B., E-mail: marica.ericson@chem.gu.se [Biomedical Photonics Group, Department of Chemistry and Molecular Biology, University of Gothenburg, Kemivägen 10, 412 96 Gothenburg (Sweden); Grönbeck, Henrik [Department of Applied Physics, Chalmers University of Technology, Kemivägen 9, 412 96 Gothenburg (Sweden)

    2015-12-07

    Gold nanoparticles can be visualized in far-field multiphoton laser-scanning microscopy (MPM) based on the phenomena of multiphoton induced luminescence (MIL). This is of interest for biomedical applications, e.g., for cancer diagnostics, as MPM allows for working in the near-infrared (NIR) optical window of tissue. It is well known that the aggregation of particles causes a redshift of the plasmon resonance, but its implications for MIL applying far-field MPM should be further exploited. Here, we explore MIL from 10 nm gold nanospheres that are chemically deposited on glass substrates in controlled coverage gradients using MPM operating in NIR range. The substrates enable studies of MIL as a function of inter-particle distance and clustering. It was shown that MIL was only detected from areas on the substrates where the particle spacing was less than one particle diameter, or where the particles have aggregated. The results are interpreted in the context that the underlying physical phenomenon of MIL is a sequential two-photon absorption process, where the first event is driven by the plasmon resonance. It is evident that gold nanospheres in this size range have to be closely spaced or clustered to exhibit detectable MIL using far-field MPM operating in the NIR region.

  7. Insights on proximity effect and multiphoton induced luminescence from gold nanospheres in far field optical microscopy

    International Nuclear Information System (INIS)

    Borglin, Johan; Guldbrand, Stina; Evenbratt, Hanne; Kirejev, Vladimir; Ericson, Marica B.; Grönbeck, Henrik

    2015-01-01

    Gold nanoparticles can be visualized in far-field multiphoton laser-scanning microscopy (MPM) based on the phenomena of multiphoton induced luminescence (MIL). This is of interest for biomedical applications, e.g., for cancer diagnostics, as MPM allows for working in the near-infrared (NIR) optical window of tissue. It is well known that the aggregation of particles causes a redshift of the plasmon resonance, but its implications for MIL applying far-field MPM should be further exploited. Here, we explore MIL from 10 nm gold nanospheres that are chemically deposited on glass substrates in controlled coverage gradients using MPM operating in NIR range. The substrates enable studies of MIL as a function of inter-particle distance and clustering. It was shown that MIL was only detected from areas on the substrates where the particle spacing was less than one particle diameter, or where the particles have aggregated. The results are interpreted in the context that the underlying physical phenomenon of MIL is a sequential two-photon absorption process, where the first event is driven by the plasmon resonance. It is evident that gold nanospheres in this size range have to be closely spaced or clustered to exhibit detectable MIL using far-field MPM operating in the NIR region

  8. 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

  9. 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

    carried out using a total of seven emission bands between 1.5 and 4.5 eV, and the behavior of these bands was examined as a function of the annealing temperature. An emission band at ∼3.44 eV (360 nm) was found to be strongly enhanced when the annealing temperature was increased to 500 °C, and this band underwent a significant reduction in intensity with further increase in temperature. Furthermore, a new emission band at ∼3.73 eV (330 nm) became apparent for annealing temperatures in the range 600–700 °C. These new experimental results are discussed within the context of the model presented in this paper. -- Highlights: • Analytical model for luminescence lifetimes in quartz with two luminescence centers. • Results from model are in agreement with published experimental data. • Describes variation of lifetimes with annealing and stimulation temperature. • New radioluminescence measurements fitted seven emission bands 1.5–4.5 eV.

  10. Synthesis and Features of Luminescent Bromo- and Iodohectorite Nanoclay Materials

    Directory of Open Access Journals (Sweden)

    Hellen Silva Santos

    2017-11-01

    Full Text Available The smectites represent a versatile class of clay minerals with broad usage in industrial applications, e.g., cosmetics, drug delivery, bioimaging, etc. Synthetic hectorite Na0.7(Mg5.5Li0.3[Si8O20](OH4 is a distinct material from this class due to its low-cost production method that allows to design its structure to match better the applications. In the current work, we have synthesized for the first time ever nanoclay materials based on the hectorite structure but with the hydroxyl groups (OH− replaced by Br− or I−, yielding bromohectorite (Br-Hec and iodohectorite (I-Hec. It was aimed that these materials would be used as phosphors. Thus, OH− replacement was done to avoid luminescence quenching by multiphonon de-excitation. The crystal structure is similar to nanocrystalline fluorohectorite, having the d001 spacing of 14.30 Å and 3 nm crystallite size along the 00l direction. The synthetic materials studied here show strong potential to act as host lattices for optically active species, possessing mesoporous structure with high specific surface area (385 and 363 m2 g−1 for Br-Hec and I-Hec, respectively and good thermal stability up to 800 °C. Both materials also present strong blue-green emission under UV radiation and short persistent luminescence (ca. 5 s. The luminescence features are attributed to Ti3+/TiIV impurities acting as the emitting center in these materials.

  11. 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.

  12. 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

  13. 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

  14. 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

  15. 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.

  16. 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.

  17. 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.

  18. Identifying irradiated flour by photo-stimulated luminescence technique

    International Nuclear Information System (INIS)

    Ros Anita Ahmad Ramli; Muhammad Samudi Yasir; Zainon Othman; Wan Saffiey Wan Abdullah

    2013-01-01

    Full-text: The photo-stimulated luminescence technique is recommended by European Committee for standardization for the detection food irradiation (EN 13751:2009). This study shows on luminescence technique to identify gamma irradiated five types of flour (corn flour, tapioca flour, wheat flour, glutinos rice flour and rice flour) at three difference dose levels in the range 0.2 - 1 kGy. The signal level is compare with two thresholds (700 and 5000). The majority of irradiated samples produce a strong signal above the upper threshold (5000 counts/ 60 s). All the control samples gave negative screening result while the signals below the lower threshold (700 counts/ 60s) suggest that the sample has not been irradiated. A few samples show the signal levels between the two thresholds (intermediate signals) suggest that further investigation. Reported procedure was also tested over 60 days, confirming the applicability and feasibility of proposed methods. (author)

  19. Handbook of luminescent semiconductor materials

    CERN Document Server

    Bergman, Leah

    2011-01-01

    Photoluminescence spectroscopy is an important approach for examining the optical interactions in semiconductors and optical devices with the goal of gaining insight into material properties. With contributions from researchers at the forefront of this field, Handbook of Luminescent Semiconductor Materials explores the use of this technique to study semiconductor materials in a variety of applications, including solid-state lighting, solar energy conversion, optical devices, and biological imaging. After introducing basic semiconductor theory and photoluminescence principles, the book focuses

  20. Electrostatic probes in luminescent discharges

    International Nuclear Information System (INIS)

    Cunha Raposo, C. da.

    1980-01-01

    A system to produce luminescent type plasma by continuos discharge and ionization by high frequency was constructed. The ionization was done in the air and in the argon under pressures from 3 to 10 mmHg. The parameters of a non magnetized collisional plasma and the parameters of a magnetized plasma such as, density, eletron temperature and potential, using a Langmuir probe with plane geometry, were determined. (M.C.K.) [pt

  1. Luminescence studies on phosphor screens

    International Nuclear Information System (INIS)

    Panayiotakis, G.; Nomikos, C.; Bakas, A.; Proimos, B.

    1994-01-01

    We report our results on x-ray phosphor screens prepared of some new materials focusing attention on their efficiency under fluoroscopy conditions, on optimization conditions and on comparisons among the various materials. All data are presented in absolute values. A theoretical model is presented, that takes into account the granular structure of the screens, permitting the explanation and prediction of the luminescence properties of the screens. (authors)

  2. Luminescence studies on phosphor screens

    Energy Technology Data Exchange (ETDEWEB)

    Panayiotakis, G; Nomikos, C; Bakas, A; Proimos, B [Medical Physics Department, University of Patras, 265 00 Patras, Greece (Greece)

    1994-12-31

    We report our results on x-ray phosphor screens prepared of some new materials focusing attention on their efficiency under fluoroscopy conditions, on optimization conditions and on comparisons among the various materials. All data are presented in absolute values. A theoretical model is presented, that takes into account the granular structure of the screens, permitting the explanation and prediction of the luminescence properties of the screens. (authors). 12 refs, 3 figs.

  3. Time domain functional NIRS imaging for human brain mapping.

    Science.gov (United States)

    Torricelli, Alessandro; Contini, Davide; Pifferi, Antonio; Caffini, Matteo; Re, Rebecca; Zucchelli, Lucia; Spinelli, Lorenzo

    2014-01-15

    This review is aimed at presenting the state-of-the-art of time domain (TD) functional near-infrared spectroscopy (fNIRS). We first introduce the physical principles, the basics of modeling and data analysis. Basic instrumentation components (light sources, detection techniques, and delivery and collection systems) of a TD fNIRS system are described. A survey of past, existing and next generation TD fNIRS systems used for research and clinical studies is presented. Performance assessment of TD fNIRS systems and standardization issues are also discussed. Main strengths and weakness of TD fNIRS are highlighted, also in comparison with continuous wave (CW) fNIRS. Issues like quantification of the hemodynamic response, penetration depth, depth selectivity, spatial resolution and contrast-to-noise ratio are critically examined, with the help of experimental results performed on phantoms or in vivo. Finally we give an account on the technological developments that would pave the way for a broader use of TD fNIRS in the neuroimaging community. Copyright © 2013 The Authors. Published by Elsevier Inc. All rights reserved.

  4. Designing and testing a wearable, wireless fNIRS patch.

    Science.gov (United States)

    Abtahi, Mohammadreza; Cay, Gozde; Saikia, Manob Jyoti; Mankodiya, Kunal

    2016-08-01

    Optical brain monitoring using near infrared (NIR) light has got a lot of attention in order to study the complexity of the brain due to several advantages as oppose to other methods such as EEG, fMRI and PET. There are a few commercially available functional NIR spectroscopy (fNIRS) brain monitoring systems, but they are still non-wearable and pose difficulties in scanning the brain while the participants are in motion. In this work, we present our endeavors to design and test a low-cost, wireless fNIRS patch using NIR light sources at wavelengths of 770 and 830nm, photodetectors and a microcontroller to trigger the light sources, read photodetector's output and transfer data wirelessly (via Bluetooth) to a smart-phone. The patch is essentially a 3-D printed wearable system, recording and displaying the brain hemodynamic responses on smartphone, also eliminates the need for complicated wiring of the electrodes. We have performed rigorous lab experiments on the presented system for its functionality. In a proof of concept experiment, the patch detected the NIR absorption on the arm. Another experiment revealed that the patch's battery could last up to several hours with continuous fNIRS recording with and without wireless data transfer.

  5. 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

  6. 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.)

  7. 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.

  8. Discuss on luminescence dose data analysis technology

    International Nuclear Information System (INIS)

    Ma Xinhua; Xiao Wuyun; Ai Xianyun; Shi Zhilan; Liu Ying

    2009-01-01

    This article describes the development of luminescence dose data measurement and processing technology. General design planning of luminescence dose data measurement and processing technology is put forward with the diverse demands. The emphasis is focused on dose data processing method, luminescence curve analysis method, using of network, mechanics of communication among computers, data base management system of individual dose in this paper. The main methods and skills used in this technology as well as their advantages are also discussed. And it offers general design references for development luminescence dose data processing software. (authors)

  9. NIRS inaugurated as IAEA Collaborating Centre. Its presence and function

    International Nuclear Information System (INIS)

    Yonekura, Yoshiharu; Watanabe, Naoyuki; Sakai, Kazuo; Kamada, Tadashi; Imai, Reiko; Fujibayashi, Yasuhisa; Nakane, Takeshi; Burkart, W.; Chhem, R.; Matsuura, Shojiro

    2010-01-01

    The feature article is the collection of documents commemorating the 2010 designation of National Institute of Radiological Sciences (NIRS) as one of International Atomic Energy Agency (IAEA) Collaborating Centres (CC) again, involving 4 introductory chapters containing 9 sections in total. The IAEA-CC concept, essentially for the 4-year project, started to globally give shape by designating 3 organizations in some countries in 2004, NIRS as a CC worked from 2006 and the present designation is the renewed one. There are 17 IAEA-CCs at present. The title of Chapter 1 of the article is the same as above title by NIRS President and of Chapter 2, ''IAEA-CC scheme'' by NIRS Senior Specialist/ professor of Gunma Pref. College of Health Sciences/ former IAEA staff. Chapter 3 entitled ''Research Development of Next Four Years in Three Collaboration Areas'', contains 3 topics of the very areas mainly responsible to the project, of biological effect and mechanism of low dose radiation by NIRS Director of Res. Center for Radiation Protection, IAEA-CC plan (radiotherapy) by the Director for Charged Particle Therapy, and IAEA-CC activity and research at Molecular Imaging Center by its Director. Chapter 4 entitled ''Expectation to NIRS'' contains four topics; Expectations for the reinforcement of collaboration with IAEA whose new priority is cancer control by the Japanese Ambassador Extraordinary and Plenipotentiary in Vienna; Welcoming NIRS to join IAEA-CC network (an interview with IAEA Deputy Director General and Head of Nuclear Sciences and Applications); Honoured to invite NIRS to establish a new partnership with IAEA (an interview with IAEA Director of Division of Human Health, Dept. of Nuclear Sciences and Applications); Expectation to NIRS in peaceful use of nuclear and radiation by President of the Nuclear Safety Research Association. (T.T.)

  10. Brain Functional Connectivity in MS: An EEG-NIRS Study

    Science.gov (United States)

    2015-10-01

    1 AWARD NUMBER: W81XWH-14-1-0582 TITLE: Brain Functional Connectivity in MS: An EEG -NIRS Study PRINCIPAL INVESTIGATOR: Heather Wishart...Functional Connectivity in MS: An EEG -NIRS Study 5b. GRANT NUMBER W81XWH-14-1-0582 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER Heather...electrical ( EEG ) and blood volume and blood oxygen-based (NIRS and fMRI) signals, and to use the results to help optimize blood oxygen level

  11. Identification of yellow luminescence centers in Be-doped GaN through pressure-dependent studies

    Science.gov (United States)

    Teisseyre, Henryk; Lyons, John L.; Kaminska, Agata; Jankowski, Dawid; Jarosz, Dawid; Boćkowski, Michał; Suchocki, Andrzej; Van de Walle, Chris G.

    2017-06-01

    Effective acceptor doping of wide-band-gap semiconductors is still an outstanding problem. Beryllium has been suggested as a shallow acceptor in GaN, but despite sporadic announcements, Be-induced p-type doping has never been practically realized. Be-doped GaN possesses two luminescence bands; one at 3.38 eV and a second near 2.2 eV at an energy close to that of the parasitic yellow luminescence often found in undoped GaN crystals. We have performed high hydrostatic pressure studies of bulk, Be-doped gallium nitride crystals using the diamond anvil cell technique. We observed a splitting of the yellow luminescence line under hydrostatic pressure into two components, one which is strongly dependent on applied pressure and another whose pressure dependence is more modest. Together with hybrid functional calculations, we attribute the strongly-varying component to the beryllium-oxygen complex. The second component of the yellow luminescence possesses very similar pressure behavior to the yellow luminescence observed in undoped samples grown by the same method, behavior which we find consistent with the CN acceptor. At higher pressure, we observe the vanishing of yellow luminescence and a rapid increase in luminescence intensity of the UV line. We explain this as the pressure-induced transformation of the Be-O complex from a highly localized state with large lattice relaxation to a delocalized state with limited lattice relaxation.

  12. 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.

  13. 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.

  14. The Effect of Motion Artifacts on Near-Infrared Spectroscopy (NIRS Data and Proposal of a Video-NIRS System

    Directory of Open Access Journals (Sweden)

    Masayuki Satoh

    2017-11-01

    Full Text Available Aims: The aims of this study were (1 to investigate the influence of physical movement on near-infrared spectroscopy (NIRS data, (2 to establish a video-NIRS system which simultaneously records NIRS data and the subject’s movement, and (3 to measure the oxygenated hemoglobin (oxy-Hb concentration change (Δoxy-Hb during a word fluency (WF task. Experiment 1: In 5 healthy volunteers, we measured the oxy-Hb and deoxygenated hemoglobin (deoxy-Hb concentrations during 11 kinds of facial, head, and extremity movements. The probes were set in the bilateral frontal regions. The deoxy-Hb concentration was increased in 85% of the measurements. Experiment 2: Using a pillow on the backrest of the chair, we established the video-NIRS system with data acquisition and video capture software. One hundred and seventy-six elderly people performed the WF task. The deoxy-Hb concentration was decreased in 167 subjects (95%. Experiment 3: Using the video-NIRS system, we measured the Δoxy-Hb, and compared it with the results of the WF task. Δoxy-Hb was significantly correlated with the number of words. Conclusion: Like the blood oxygen level-dependent imaging effect in functional MRI, the deoxy-Hb concentration will decrease if the data correctly reflect the change in neural activity. The video-NIRS system might be useful to collect NIRS data by recording the waveforms and the subject’s appearance simultaneously.

  15. 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.

  16. Compensation techniques in NIRS proton beam radiotherapy

    International Nuclear Information System (INIS)

    Akanuma, A.; Majima, H.; Furukawa, S.

    1982-01-01

    Proton beam has the dose distribution advantage in radiation therapy, although it has little advantage in biological effects. One of the best advantages is its sharp fall off of dose after the peak. With proton beam, therefore, the dose can be given just to cover a target volume and potentially no dose is delivered thereafter in the beam direction. To utilize this advantage, bolus techniques in conjunction with CT scanning are employed in NIRS proton beam radiation therapy planning. A patient receives CT scanning first so that the target volume can be clearly marked and the radiation direction and fixation method can be determined. At the same time bolus dimensions are calculated. The bolus frames are made with dental paraffin sheets according to the dimensions. The paraffin frame is replaced with dental resin. Alginate (a dental impression material with favorable physical density and skin surface contact) is now employed for the bolus material. With fixation device and bolus on, which are constructed individually, the patient receives CT scanning again prior to a proton beam treatment in order to prove the devices are suitable. Alginate has to be poured into the frame right before each treatments. Further investigations are required to find better bolus materials and easier construction methods

  17. Compensation techniques in NIRS proton beam radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Akanuma, A. (Univ. of Tokyo, Japan); Majima, H.; Furukawa, S.

    1982-09-01

    Proton beam has the dose distribution advantage in radiation therapy, although it has little advantage in biological effects. One of the best advantages is its sharp fall off of dose after the peak. With proton beam, therefore, the dose can be given just to cover a target volume and potentially no dose is delivered thereafter in the beam direction. To utilize this advantage, bolus techniques in conjunction with CT scanning are employed in NIRS proton beam radiation therapy planning. A patient receives CT scanning first so that the target volume can be clearly marked and the radiation direction and fixation method can be determined. At the same time bolus dimensions are calculated. The bolus frames are made with dental paraffin sheets according to the dimensions. The paraffin frame is replaced with dental resin. Alginate (a dental impression material with favorable physical density and skin surface contact) is now employed for the bolus material. With fixation device and bolus on, which are constructed individually, the patient receives CT scanning again prior to a proton beam treatment in order to prove the devices are suitable. Alginate has to be poured into the frame right before each treatments. Further investigations are required to find better bolus materials and easier construction methods.

  18. SHARK-NIR system design analysis overview

    Science.gov (United States)

    Viotto, Valentina; Farinato, Jacopo; Greggio, Davide; Vassallo, Daniele; Carolo, Elena; Baruffolo, Andrea; Bergomi, Maria; Carlotti, Alexis; De Pascale, Marco; D'Orazi, Valentina; Fantinel, Daniela; Magrin, Demetrio; Marafatto, Luca; Mohr, Lars; Ragazzoni, Roberto; Salasnich, Bernardo; Verinaud, Christophe

    2016-08-01

    In this paper, we present an overview of the System Design Analysis carried on for SHARK-NIR, the coronagraphic camera designed to take advantage of the outstanding performance that can be obtained with the FLAO facility at the LBT, in the near infrared regime. Born as a fast-track project, the system now foresees both coronagraphic direct imaging and spectroscopic observing mode, together with a first order wavefront correction tool. The analysis we here report includes several trade-offs for the selection of the baseline design, in terms of optical and mechanical engineering, and the choice of the coronagraphic techniques to be implemented, to satisfy both the main scientific drivers and the technical requirements set at the level of the telescope. Further care has been taken on the possible exploitation of the synergy with other LBT instrumentation, like LBTI. A set of system specifications is then flown down from the upper level requirements to finally ensure the fulfillment of the science drivers. The preliminary performance budgets are presented, both in terms of the main optical planes stability and of the image quality, including the contributions of the main error sources in different observing modes.

  19. HARDERSEN IRTF ASTEROID NIR REFLECTANCE SPECTRA V1.0

    Data.gov (United States)

    National Aeronautics and Space Administration — This dataset includes average near-infrared (NIR) reflectance spectra for 68 main-belt asteroids that were observed at the NASA Infrared Telescope Facility (IRTF),...

  20. NIRS Characterization of Paper Pulps to Predict Kappa Number

    Directory of Open Access Journals (Sweden)

    Ana Moral

    2015-01-01

    Full Text Available Rice is one of the most abundant food crops in the world and its straw stands as an important source of fibres both from an economic and an environmental point of view. Pulp characterization is of special relevance in works involving alternative raw materials, since pulp properties are closely linked to the quality of the final product. One of the analytical techniques that can be used in pulp characterization is near-infrared spectroscopy (NIRS. The use of NIRS has economic and technical advantages over conventional techniques. This paper aims to discuss the convenience of using NIRS to predict Kappa number in rice straw pulps produced under different conditions. We found that the resulting Kappa number can be acceptably estimated by NIRS, as the errors obtained with that method are similar to those found for other techniques.

  1. Toward Adaptation of fNIRS Instrumentation to Airborne Environments

    Science.gov (United States)

    Adamovsky, Grigory; Mackey, Jeffrey; Harrivel, Angela; Hearn, Tristan; Floyd, Bertram

    2014-01-01

    The paper reviews potential applications of functional Near-Infrared Spectroscopy (fNIRS), a well-known medical diagnostic technique, to monitoring the cognitive state of pilots with a focus on identifying ways to adopt this technique to airborne environments. We also discuss various fNIRS techniques and the direction of technology maturation of associated hardware in view of their potential for miniaturization, maximization of data collection capabilities, and user friendliness.

  2. Visible luminescence studies in the infrared multiphoton dissociation of 1,2-dichloro-1,1-difluoroethane

    Science.gov (United States)

    Pushpa, K. K.; Kumar, Awadesh; Naik, P. D.; Annaji Rao, K.; Parthasarathy, V.; Sarkar, S. K.; Mittal, J. P.

    1997-11-01

    A strong visible luminescence was observed in the CO 2 laser induced infrared multiphoton dissociation of 1,2-dichloro-1,1-difluoroethane. The emission observed between 350-750 nm is attributed to electronically excited carbene CF 2ClCH. The temporal profile of this luminescence was studied as a function of laser pulse duration, pulse energy, excitation frequency and substrate pressure. A suitable dissociation mechanism is presented considering various channels of IRMPD of this molecule.

  3. 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

  4. 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

  5. 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...

  6. 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 ...

  7. In vivo near infrared (NIRS) sensor attachment using fibrin bioadhesive

    Science.gov (United States)

    Macnab, Andrew; Pagano, Roberto; Kwon, Brian; Dumont, Guy; Shadgan, Babak

    2018-02-01

    Background: `Tisseel' (Baxter Healthcare, Deerfield, IL) is a fibrin-based sealant that is commonly used during spine surgery to augment dural repairs. We wish to intra-operatively secure a near infrared spectroscopy (NIRS) sensor to the dura in order to monitor the tissue hemodynamics of the underlying spinal cord. To determine if `Tisseel' sealant adversely attenuates NIR photon transmission. Methods: We investigated `Tisseel' in both an in vitro and in vivo paradigm. For in vitro testing, we used a 1 mm pathlength cuvette containing either air or `Tisseel' interposed between a NIR light source (760 and 850 nm) and a photodiode detector and compared transmittance. For in vivo testing, a continuous wave (760 and 850 nm) spatiallyresolved NIRS device was placed over the triceps muscle using either conventional skin apposition (overlying adhesive bandage) or bioadhesion with `Tisseel'. Raw optical data and tissue saturation index (TSI%) collected at rest were compared. Results: In-vitro NIR light absorption by `Tisseel' was very high, with transmittance reduced by 95% compared to air. In-vivo muscle TSI% values were 80% with conventional attachment and 20% using fibrin glue. Conclusion: The optical properties of `Tisseel' significantly attenuate NIR light during in-vitro transmittance and critically compromise photon transmission in-vivo.

  8. Epoch making NIRS studies seen through citation trends

    International Nuclear Information System (INIS)

    Dan, Ippeita

    2009-01-01

    Near-infrared spectroscopy (NIRS) studies through citation trends are investigated of literature concerning only the brain function measurement and its methodology together with NIRS principle, technological development, present state and future view. Investigation is conducted firstly for the survey of important author name of those concerned papers in Web of Science and Google Scholar with search words of NIRS, brain and optical topography as an option. Second, >100 papers of those authors citing any of them are picked up and their papers are ranked in accordance with Web of Science citation number, of which top-nineteen are presented here. Impact and epoch making papers are reviewed with explanations of: the establishment of measuring technology of cerebral blood flow change and subsequent brain function by NIRS; development with multi-channel detection; simultaneous measurement with other imaging modalities; examination of NIRS validity; spatial analysis of NIRS; and measurement of brain function. The highest times of citation are 1,238 of the paper by F. F. Jobsis in 'Science' (1977). It should be noted that 10 of top 19 papers are those by Japanese authors. However, review articles omitted in the present literature survey are mostly described by foreign authors: an effort to systemize the concerned fields might be required in this country. (K.T.)

  9. Microscopic modeling of photoluminescence of strongly disordered semiconductors

    International Nuclear Information System (INIS)

    Bozsoki, P.; Kira, M.; Hoyer, W.; Meier, T.; Varga, I.; Thomas, P.; Koch, S.W.

    2007-01-01

    A microscopic theory for the luminescence of ordered semiconductors is modified to describe photoluminescence of strongly disordered semiconductors. The approach includes both diagonal disorder and the many-body Coulomb interaction. As a case study, the light emission of a correlated plasma is investigated numerically for a one-dimensional two-band tight-binding model. The band structure of the underlying ordered system is assumed to correspond to either a direct or an indirect semiconductor. In particular, luminescence and absorption spectra are computed for various levels of disorder and sample temperature to determine thermodynamic relations, the Stokes shift, and the radiative lifetime distribution

  10. Cerenkov luminescence tomography based on preconditioning orthogonal matching pursuit

    Science.gov (United States)

    Liu, Haixiao; Hu, Zhenhua; Wang, Kun; Tian, Jie; Yang, Xin

    2015-03-01

    Cerenkov luminescence imaging (CLI) is a novel optical imaging method and has been proved to be a potential substitute of the traditional radionuclide imaging such as positron emission tomography (PET) and single-photon emission computed tomography (SPECT). This imaging method inherits the high sensitivity of nuclear medicine and low cost of optical molecular imaging. To obtain the depth information of the radioactive isotope, Cerenkov luminescence tomography (CLT) is established and the 3D distribution of the isotope is reconstructed. However, because of the strong absorption and scatter, the reconstruction of the CLT sources is always converted to an ill-posed linear system which is hard to be solved. In this work, the sparse nature of the light source was taken into account and the preconditioning orthogonal matching pursuit (POMP) method was established to effectively reduce the ill-posedness and obtain better reconstruction accuracy. To prove the accuracy and speed of this algorithm, a heterogeneous numerical phantom experiment and an in vivo mouse experiment were conducted. Both the simulation result and the mouse experiment showed that our reconstruction method can provide more accurate reconstruction result compared with the traditional Tikhonov regularization method and the ordinary orthogonal matching pursuit (OMP) method. Our reconstruction method will provide technical support for the biological application for Cerenkov luminescence.

  11. Luminescent lanthanide reporters: new concepts for use in bioanalytical applications

    International Nuclear Information System (INIS)

    Vuojola, Johanna; Soukka, Tero

    2014-01-01

    Lanthanides represent the chemical elements from lanthanum to lutetium. They intrinsically exhibit some very exciting photophysical properties, which can be further enhanced by incorporating the lanthanide ion into organic or inorganic sensitizing structures. A very popular approach is to conjugate the lanthanide ion to an organic chromophore structure forming lanthanide chelates. Another approach, which has quickly gained interest, is to incorporate the lanthanide ions into nanoparticle structures, thus attaining improved specific activity and a large surface area for biomolecule immobilization. Lanthanide-based reporters, when properly shielded from the quenching effects of water, usually express strong luminescence emission, multiple narrow emission lines covering a wide wavelength range, and exceptionally long excited state lifetimes enabling time-gated luminescence detection. Because of these properties, lanthanide-based reporters have found widespread applications in various fields of life. This review focuses on the field of bioanalytical applications. Luminescent lanthanide reporters and assay formats utilizing these reporters pave the way for increasingly sensitive, simple, and easily automated bioanalytical applications. (topical review)

  12. 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.

  13. 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

  14. 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.

  15. Luminescence detection of irradiated foods

    International Nuclear Information System (INIS)

    Sanderson, D.C.W.

    1990-01-01

    The need for forensic tests to identify irradiated foods has been widely recognised at a time of growing international trade in such products and impending changes in UK and EEC legislation to control the process. This paper outlines the requirements for and of such tests, and discusses recent developments in luminescence approaches aimed at meeting the needs of public analysts, retailers and consumers. Detecting whether or not food has been irradiated, and if so to what dose, is one of the challenges which food irradiation poses to the scientist. (author)

  16. Rupture luminescence from natural fibers

    Science.gov (United States)

    Li, W.; Haneman, D.

    1999-12-01

    Fibers of cotton and wool, and samples of paper, have been ruptured in tension in vacuum and in air, and give detectable luminescence in the visible range. All have a common emission peak at around 2.0 eV, which is ascribed to the deexcitation of states excited by the rupture of organic chain molecule bonds. Rubber bands give stronger emission in air, but no emission in vacuum, suggesting the material breaks only at weak interchain bonds. Mohair, cat, and horse hair also give emission in air. The phenomena reveal effects that would occur widely in nature.

  17. NIR-fluorescent dye doped silica nanoparticles for in vivo imaging, sensing and theranostic

    Science.gov (United States)

    Rampazzo, Enrico; Genovese, Damiano; Palomba, Francesco; Prodi, Luca; Zaccheroni, Nelsi

    2018-04-01

    The development of nanostructures devoted to in vivo imaging and theranostic applications is one of the frontier fields of research worldwide. In this context, silica nanoparticles (SiO2-NPs) offer unquestionable positive properties: silica is intrinsically non-toxic, several versatile and accessible synthetic methods are available and many variations are possible, both in terms of porosity and functionalization for delivery and targeting purposes, respectively. Moreover, the accumulation of several dyes within a single nanostructure offers remarkable possibilities to produce very bright and photostable luminescent nanosystems. Advancements in imaging technology, bioassay, fluorescent molecular probes have boosted the efforts to develop dye doped fluorescent SiO2-NPs, but despite this, only a quite limited set of systems are applicable in vivo. Herein we discuss selected examples that appeared in the literature between 2013-17, with imaging capabilities in vivo and characterized by a significant near infrared (NIR) fluorescence emission. We present here very promising strategies to develop SiO2-NPs for diagnostic and therapeutic applications—some of which are already in clinical trials—and the possibility to develop bio-erodable SiO2-NPs. We are convinced that all these findings will be the basis for the spread of SiO2-NPs into clinical use in the near future.

  18. NIRS-Based Hyperscanning Reveals Inter-brain Neural Synchronization during Cooperative Jenga Game with Face-to-Face Communication.

    Science.gov (United States)

    Liu, Ning; Mok, Charis; Witt, Emily E; Pradhan, Anjali H; Chen, Jingyuan E; Reiss, Allan L

    2016-01-01

    Functional near-infrared spectroscopy (fNIRS) is an increasingly popular technology for studying social cognition. In particular, fNIRS permits simultaneous measurement of hemodynamic activity in two or more individuals interacting in a naturalistic setting. Here, we used fNIRS hyperscanning to study social cognition and communication in human dyads engaged in cooperative and obstructive interaction while they played the game of Jenga™. Novel methods were developed to identify synchronized channels for each dyad and a structural node-based spatial registration approach was utilized for inter-dyad analyses. Strong inter-brain neural synchrony (INS) was observed in the posterior region of the right middle and superior frontal gyrus, in particular Brodmann area 8 (BA8), during cooperative and obstructive interaction. This synchrony was not observed during the parallel game play condition and the dialog section, suggesting that BA8 was involved in goal-oriented social interaction such as complex interactive movements and social decision-making. INS was also observed in the dorsomedial prefrontal cortex (dmPFC), in particular Brodmann 9, during cooperative interaction only. These additional findings suggest that BA9 may be particularly engaged when theory-of-mind (ToM) is required for cooperative social interaction. The new methods described here have the potential to significantly extend fNIRS applications to social cognitive research.

  19. Toward Rechargeable Persistent Luminescence for the First and Third Biological Windows via Persistent Energy Transfer and Electron Trap Redistribution.

    Science.gov (United States)

    Xu, Jian; Murata, Daisuke; Ueda, Jumpei; Viana, Bruno; Tanabe, Setsuhisa

    2018-05-07

    Persistent luminescence (PersL) imaging without real-time external excitation has been regarded as the next generation of autofluorescence-free optical imaging technology. However, to achieve improved imaging resolution and deep tissue penetration, developing new near-infrared (NIR) persistent phosphors with intense and long duration PersL over 1000 nm is still a challenging but urgent task in this field. Herein, making use of the persistent energy transfer process from Cr 3+ to Er 3+ , we report a novel garnet persistent phosphor of Y 3 Al 2 Ga 3 O 12 codoped with Er 3+ and Cr 3+ (YAG G:Er-Cr), which shows intense Cr 3+ PersL (∼690 nm) in the deep red region matching well with the first biological window (NIR-I, 650-950 nm) and Er 3+ PersL (∼1532 nm) in the NIR region matching well with the third biological window (NIR-III, 1500-1800 nm). The optical imaging through raw-pork tissues (thickness of 1 cm) suggests that the emission band of Er 3+ can achieve higher spatial resolution and more accurate signal location than that of Cr 3+ due to the reduced light scattering at longer wavelengths. Furthermore, by utilizing two independent electron traps with two different trap depths in YAG G:Er-Cr, the Cr 3+ /Er 3+ PersL can even be recharged in situ by photostimulation with 660 nm LED thanks to the redistribution of trapped electrons from the deep trap to the shallow one. Our results serve as a guide in developing promising NIR (>1000 nm) persistent phosphors for long-term optical imaging.

  20. Sensitivity of fNIRS to cognitive state and load

    Directory of Open Access Journals (Sweden)

    Frank Anthony Fishburn

    2014-02-01

    Full Text Available Functional near-infrared spectroscopy (fNIRS is an emerging low-cost noninvasive neuroimaging technique that measures cortical bloodflow. While fNIRS has gained interest as a potential alternative to fMRI for use with clinical and pediatric populations, it remains unclear whether fNIRS has the necessary sensitivity to serve as a replacement for fMRI. The present study set out to examine whether fNIRS has the sensitivity to detect linear changes in activation and functional connectivity in response to cognitive load, and functional connectivity changes when transitioning from a task-free resting state to a task. Sixteen young adult subjects were scanned with a continuous-wave fNIRS system during a 10-minute resting-state scan followed by a letter n-back task with three load conditions. Five optical probes were placed over frontal and parietal cortices, covering bilateral dorsolateral PFC (dlPFC, bilateral ventrolateral PFC (vlPFC, frontopolar cortex (FP, and bilateral parietal cortex. Activation was found to scale linearly with working memory load in bilateral prefrontal cortex. Functional connectivity increased with increasing n-back loads for fronto-parietal, interhemispheric dlPFC, and local connections. Functional connectivity differed between the resting state scan and the n-back scan, with fronto-parietal connectivity greater during the n-back, and interhemispheric vlPFC connectivity greater during rest. These results demonstrate that fNIRS is sensitive to both cognitive load and state, suggesting that fNIRS is well-suited to explore the full complement of neuroimaging research questions and will serve as a viable alternative to fMRI.

  1. 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)

  2. Microwave hydrothermal synthesis and upconversion luminescence ...

    Indian Academy of Sciences (India)

    2017-10-31

    Oct 31, 2017 ... properties such as blue emission around 480 nm and NIR emission near 800 nm [10 ... the low phonon energies of the fluoride compounds [13,14]. However, they are .... scanning electron microscope (SEM). The UC lumines-.

  3. 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.

  4. Near infrared and upconversion luminescence behaviour of Er{sup 3+}/Yb{sup 3+} codoped boro-tellurite glasses

    Energy Technology Data Exchange (ETDEWEB)

    Maheshvaran, K. [Department of Physics, Gandhigram Rural Institute - Deemed University, Gandhigram - 624302, India and Department of Physics, K.S. Rangasamy College of Technology, Trichengode - 637215 (India); Arunkumar, S., E-mail: mari-ram2000@yahoo.com; Vijayakumar, R., E-mail: mari-ram2000@yahoo.com; Marimuthu, K., E-mail: mari-ram2000@yahoo.com [Department of Physics, Gandhigram Rural Institute − Deemed University, Gandhigram - 624302 (India)

    2014-04-24

    The broadband NIR and upconversion luminescence behavior in a new series of Er{sup 3+}/Yb{sup 3+} codoped TeO{sub 2}-B{sub 2}O{sub 3}-SrO-BaO-Li{sub 2}O-LiF glasses have been studied exciting at a wavelength of 980 nm using semiconductor laser. A broadband emission is observed from 1450 to 1650 nm with a full width at half maximum (FWHM) around 165 nm in 0.5wt% Yb{sup 3+} ion content E0.5YLTB glass. The radiative parameters such as transition probability (A), stimulated emission cross-section (σ{sup E}), experimental and calculated branching ratios (β{sub R}), optical gain width (σ{sub p}×FWHM) and radiative lifetime (τ{sub cal}) have been calculated for the {sup 4}I{sub 13/2}→{sup 4}I{sub 15/2} NIR emission. Upconversion luminescence spectra of the prepared glasses have been studied and the ESA and ET processes have also been discussed and reported.

  5. 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.

  6. Estimation of Anthocyanin Content of Berries by NIR Method

    International Nuclear Information System (INIS)

    Zsivanovits, G.; Ludneva, D.; Iliev, A.

    2010-01-01

    Anthocyanin contents of fruits were estimated by VIS spectrophotometer and compared with spectra measured by NIR spectrophotometer (600-1100 nm step 10 nm). The aim was to find a relationship between NIR method and traditional spectrophotometric method. The testing protocol, using NIR, is easier, faster and non-destructive. NIR spectra were prepared in pairs, reflectance and transmittance. A modular spectrocomputer, realized on the basis of a monochromator and peripherals Bentham Instruments Ltd (GB) and a photometric camera created at Canning Research Institute, were used. An important feature of this camera is the possibility offered for a simultaneous measurement of both transmittance and reflectance with geometry patterns T0/180 and R0/45. The collected spectra were analyzed by CAMO Unscrambler 9.1 software, with PCA, PLS, PCR methods. Based on the analyzed spectra quality and quantity sensitive calibrations were prepared. The results showed that the NIR method allows measuring of the total anthocyanin content in fresh berry fruits or processed products without destroying them.

  7. Luminescence studies of rare earth doped dosimeters

    International Nuclear Information System (INIS)

    Karali, T.

    1999-10-01

    The main objective of this thesis has been to address the applications and fundamentals of thermoluminescence (TL) and to contribute to existing knowledge about TL mechanisms in materials which are applied as radiation dosimeters. This issue has been explored for a long time but the mechanisms lack completeness and certainty. TL, Radioluminescence (RL) and Radio-thermoluminescence (RLTL) measurements have been conducted on a high sensitivity TL spectrometer both at low (30-290 K) and high (25-400 deg. C) temperatures, and different heat treatments (furnace and laser) were conducted in order to study the possible impurity clustering which changes the TL spectra and efficiency of the dosimeters. Studies have been based on three different host structure, namely sulphate, borates and zircon. The spectra of calcium sulphate samples doped with Tm 3+ and Dy 3+ at different concentration were examined using TL, RL and RLTL. Similar procedures were applied to the borate samples. Modifications of the material by thermal treatments convert the state of dispersion of the rare earth ions between isolated, pair or defect clusters, which alter the dosimeter efficiency. In some cases, modified geometries are detectable by movement of the line emissions such as for quenched samples which are attributable to new microcrystal line phases. The study of co-doped samples showed unequivocal evidence of a glow peak displacement of the two dopants within a single sample. This result supports the new view that RE 3+ ions could form part of a complex defect acting as both charge trap and recombination centres. Pulsed laser heating with a UV laser changed the glow curve shape and lead to strong signals. The detailed mechanisms for this process are discussed. The RL and TL spectra of synthetic zircon crystals doped with different RE 3+ ions (Pr, Sm, Eu, Gd, Ho, Dy, Er, and Yb) and phosphorus are reported. Even though there is some intrinsic emission from the host lattice the major signals are

  8. 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

  9. Highly visible-light luminescence properties of the carboxyl-functionalized short and ultrashort MWNTs

    International Nuclear Information System (INIS)

    Luo Yongsong; Xia Xiaohong; Liang Ying; Zhang Yonggang; Ren Qinfeng; Li Jialin; Jia Zhijie; Tang Yiwen

    2007-01-01

    Luminescence of the short multiwalled carbon nanotubes (MWNTs) conjugated with carboxylic acid groups has been studied. The results show that the carboxyl-functionalized short MWNTs could emit luminescence and the emission peak appears at 500 nm with a corresponding optimal excitation wavelength centering at 310 nm. When the short MWNTs are filtered through 0.15 μm polytetrafluoroethylene (PTFE) membrane, the ultrashort MWNTs are obtained from the filtrate. An interesting feature for the ultrashort MWNTs is that the emission intensity is strengthened and the peak is slightly blue shifted to 460 nm. This result indicates that the luminescence properties of MWNTs are strongly affected by the tube length. After chemical oxidization cutting, defects and carboxylic acid groups at the tube end and/or sidewall can be produced; the more shorten of MWNTs, the better dispersion and carboxylic passivation of the nanotubes, and the more intense luminescence emissions. The broad emissions are logically attributed to the trapping of excitation energy by defect sites in the carboxyl-functionalized nanotube structure. - Graphical abstract: Luminescence of the short and ultrashort multiwalled carbon nanotubes (MWNTs) conjugated with carboxylic acid groups, which is logically attributed to the trapping of excitation energy by defect sites, has been studied

  10. 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.

  11. Calibration beads containing luminescent lanthanide ion complexes

    Science.gov (United States)

    The reliability of lanthanide luminescence measurements, by both flow cytometry and digital microscopy, will be enhanced by the availability of narrow-band emitting lanthanide calibration beads. These beads can also be used to characterize spectrographic instruments, including mi...

  12. 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.

  13. 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.

  14. Synthesis, crystal structure, theoretical study and luminescence ...

    Indian Academy of Sciences (India)

    and Material Engineering, Jiangnan University, Wuxi 214122, P. R. China. cChina-Australia Joint ... School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210093, P. R. China e-mail: ..... The title complex is luminescent.

  15. 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.

  16. NIR emission and Ce{sup 3+}–Nd{sup 3+} energy transfer in LaCaAl{sub 3}O{sub 7} phosphor prepared by combustion synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Pathak, A.A. [National Power Training Institute, South Ambazari Road, Nagpur 440022 (India); Talewar, R.A., E-mail: talewarrupesh@gmail.com [Physics Department, Shri Ramdeobaba College of Engineering and Management, Katol Road, Nagpur 440013 (India); Joshi, C.P. [Physics Department, Shri Ramdeobaba College of Engineering and Management, Katol Road, Nagpur 440013 (India); Moharil, S.V. [Department of Physics, Rashtrasant Tukadoji Maharaj Nagpur University, Nagpur 440010 (India)

    2016-11-15

    Near infrared (NIR) emitting phosphor, LaCaAl{sub 3}O{sub 7}:Ce{sup 3+},Nd{sup 3+} was synthesized by one step combustion synthesis and characterized with scanning electron microscope, photoluminescence emission, photoluminescence excitation spectra and fluorescence decay measurements. When excited with UV, the phosphor gives broadband emission at 410 nm, which corresponds to the allowed 5d→4f transition of Ce{sup 3+} ions and an intense NIR emissions in the range 800–1400 nm, which are assigned to the characteristic transitions from {sup 4}I{sub 9/2,11/2,13/2} states of Nd{sup 3+} ions. The dependences of visible and NIR emissions, decay lifetime and the energy transfer efficiency (η{sub ETE}) on dopant concentrations were investigated in detail. The luminescence spectra, both in visible (VIS) and NIR regions, and decay curves of Ce{sup 3+} have been measured to prove energy transfer (ET) from Ce{sup 3+} to Nd{sup 3+}. These results demonstrate the possibility for enhancing the photovoltaic conversion efficiency of c-Si solar cell by modifying the absorption and utilizing the UV part of the solar spectrum where the efficiency of c-Si solar cell is low.

  17. fNIRS-based brain-computer interfaces: a review

    Directory of Open Access Journals (Sweden)

    Noman eNaseer

    2015-01-01

    Full Text Available A brain-computer interface (BCI is a communication system that allows the use of brain activity to control computers or other external devices. It can, by bypassing the peripheral nervous system, provide a means of communication for people suffering from severe motor disabilities or in a persistent vegetative state. In this paper, brain-signal generation tasks, noise removal methods, feature extraction/selection schemes, and classification techniques for fNIRS-based BCI are reviewed. The most common brain areas for fNIRS BCI are the primary motor cortex and the prefrontal cortex. In relation to the motor cortex, motor imagery tasks were preferred to motor execution tasks since possible proprioceptive feedback could be avoided. In relation to the prefrontal cortex, fNIRS showed a significant advantage due to no hair in detecting the cognitive tasks like mental arithmetic, music imagery, emotion induction, etc. In removing physiological noise in fNIRS data, band-pass filtering was mostly used. However, more advanced techniques like adaptive filtering, independent component analysis, multi optodes arrangement, etc. are being pursued to overcome the problem that a band-pass filter cannot be used when both brain and physiological signals occur within a close band. In extracting features related to the desired brain signal, the mean, variance, peak value, slope, skewness, and kurtosis of the noised-removed hemodynamic response were used. For classification, the linear discriminant analysis method provided simple but good performance among others: support vector machine, hidden Markov model, artificial neural network, etc. fNIRS will be more widely used to monitor the occurrence of neuro-plasticity after neuro-rehabilitation and neuro-stimulation. Technical breakthroughs in the future are expected via bundled-type probes, hybrid EEG-fNIRS BCI, and through the detection of initial dips.

  18. [Advances of NIR spectroscopy technology applied in seed quality detection].

    Science.gov (United States)

    Zhu, Li-wei; Ma, Wen-guang; Hu, Jin; Zheng, Yun-ye; Tian, Yi-xin; Guan, Ya-jing; Hu, Wei-min

    2015-02-01

    Near infrared spectroscopy (NIRS) technology developed fast in recent years, due to its rapid speed, less pollution, high-efficiency and other advantages. It has been widely used in many fields such as food, chemical industry, pharmacy, agriculture and so on. The seed is the most basic and important agricultural capital goods, and seed quality is important for agricultural production. Most methods presently used for seed quality detecting were destructive, slow and needed pretreatment, therefore, developing one kind of method that is simple and rapid has great significance for seed quality testing. This article reviewed the application and trends of NIRS technology in testing of seed constituents, vigor, disease and insect pests etc. For moisture, starch, protein, fatty acid and carotene content, the model identification rates were high as their relative contents were high; for trace organic, the identification rates were low as their relative content were low. The heat-damaged seeds with low vigor were discriminated by NIRS, the seeds stored for different time could also been identified. The discrimination of frost-damaged seeds was impossible. The NIRS could be used to identify health and infected disease seeds, and did the classification for the health degree; it could identify parts of the fungal pathogens. The NIRS could identify worm-eaten and health seeds, and further distinguished the insect species, however the identification effects for small larval and low injury level of insect pests was not good enough. Finally, in present paper existing problems and development trends for NIRS in seed quality detection was discussed, especially the single seed detecting technology which was characteristic of the seed industry, the standardization of its spectral acquisition accessories will greatly improve its applicability.

  19. 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

  20. Dynamic Filtering Improves Attentional State Prediction with fNIRS

    Science.gov (United States)

    Harrivel, Angela R.; Weissman, Daniel H.; Noll, Douglas C.; Huppert, Theodore; Peltier, Scott J.

    2016-01-01

    Brain activity can predict a person's level of engagement in an attentional task. However, estimates of brain activity are often confounded by measurement artifacts and systemic physiological noise. The optimal method for filtering this noise - thereby increasing such state prediction accuracy - remains unclear. To investigate this, we asked study participants to perform an attentional task while we monitored their brain activity with functional near infrared spectroscopy (fNIRS). We observed higher state prediction accuracy when noise in the fNIRS hemoglobin [Hb] signals was filtered with a non-stationary (adaptive) model as compared to static regression (84% +/- 6% versus 72% +/- 15%).

  1. 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.)

  2. 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)

  3. 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)

  4. 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.

  5. Preparation and luminescence properties of LaPO{sub 4}:Er,Yb nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Ha-Kyun [Advanced Materials Division, Korea Research Institute of Chemical Technology, P.O. Box 107, Yuseong, Daejeon 305-600 (Korea, Republic of)]. E-mail: hakyun@krict.re.kr; Oh, Jae-Suk [Advanced Materials Division, Korea Research Institute of Chemical Technology, P.O. Box 107, Yuseong, Daejeon 305-600 (Korea, Republic of); Seok, Sang-Il [Advanced Materials Division, Korea Research Institute of Chemical Technology, P.O. Box 107, Yuseong, Daejeon 305-600 (Korea, Republic of); Lee, Tack-Hyuck [Department of Chemistry, Paichai University, Daejeon 302-735 (Korea, Republic of)

    2005-09-15

    For possible applications as optical amplification materials in telecommunications, LaPO{sub 4}:Er,Yb nanoparticles were synthesized in a solution system and their properties were investigated by various spectroscopic techniques. The prepared nanoparticles are single-phased and present the monazite structure, the particle size being about 5 nm with a narrow size distribution. Also, it was confirmed by EA and FT-IR analyses that the surface of nanoparticles is coated with the solvent molecules used in the synthesis reaction, which possibly prevents them from agglomerating. In the NIR region, the emission of the LaPO{sub 4}:Er particles is very weak due to an efficient quenching of the {sup 4}I{sub 13/2}{yields}{sup 4}I{sub 15/2} emission by the hydroxyl groups adsorbed on the surface of the nanoparticles. On the other hand, the co-doping of Yb{sup 3+} as a sensitizer in the nanoparticles resulted in the increase of the emission intensity at 1539 nm due to the effective energy transfer from Yb{sup 3+} to Er{sup 3+}. In addition, the synthesized nanoparticles have exhibited good dispersibility into a polymer matrix and effective luminescence in the NIR region.

  6. Syntheses, structures and luminescence properties of lanthanide coordination polymers with helical character

    International Nuclear Information System (INIS)

    Zhou Ruisha; Cui Xiaobing; Song Jiangfeng; Xu Xiaoyu; Xu Jiqing; Wang Tiegang

    2008-01-01

    A series of lanthanide coordination polymers, (Him) n [Ln(ip) 2 (H 2 O)] n [Ln=La(1), Pr(2), Nd(3) and Dy(4), H 2 ip=isophthalic acid, im=imidazole] and [Y 2 (ip) 3 (H 2 O) 2 ] n .nH 2 O (5), have been synthesized and characterized by elemental analyses, infrared (IR), ultraviolet-visible-near infrared (UV-Vis-NIR) and single-crystal X-ray diffraction analyses. The isostructural compounds 1-4 possess 3-D structures with three different kinds of channels. Compound 5 features a 2-D network making of two different kinds of quadruple-helical chains. Compounds 2 and 3 present the characteristic emissions of Pr(III) and Nd(III) ions in NIR region, respectively. Compound 4 shows sensitized luminescence of Dy(III) ions in visible region. - Graphical abstract: A series of lanthanide coodination polymers, (Him) n [Ln(ip) 2 (H 2 O)] n [Ln=La(1), Pr(2), Nd(3) and Dy(4)] and [Y 2 (ip) 3 (H 2 O) 2 ] n .nH 2 O (5), have been reported. The isostructural compounds 1-4 possess 3-D structures with three different kinds of channels. Compound 5 displays a 2-D network making of two kinds of quadruple-helical chains. Display Omitted

  7. Tunable Luminescent Carbon Nanospheres with Well-Defined Nanoscale Chemistry for Synchronized Imaging and Therapy.

    Science.gov (United States)

    Mukherjee, Prabuddha; Misra, Santosh K; Gryka, Mark C; Chang, Huei-Huei; Tiwari, Saumya; Wilson, William L; Scott, John W; Bhargava, Rohit; Pan, Dipanjan

    2015-09-01

    In this work, we demonstrate the significance of defined surface chemistry in synthesizing luminescent carbon nanomaterials (LCN) with the capability to perform dual functions (i.e., diagnostic imaging and therapy). The surface chemistry of LCN has been tailored to achieve two different varieties: one that has a thermoresponsive polymer and aids in the controlled delivery of drugs, and the other that has fluorescence emission both in the visible and near-infrared (NIR) region and can be explored for advanced diagnostic modes. Although these particles are synthesized using simple, yet scalable hydrothermal methods, they exhibit remarkable stability, photoluminescence and biocompatibility. The photoluminescence properties of these materials are tunable through careful choice of surface-passivating agents and can be exploited for both visible and NIR imaging. Here the synthetic strategy demonstrates the possibility to incorporate a potent antimetastatic agent for inhibiting melanomas in vitro. Since both particles are Raman active, their dispersion on skin surface is reported with Raman imaging and utilizing photoluminescence, their depth penetration is analysed using fluorescence 3D imaging. Our results indicate a new generation of tunable carbon-based probes for diagnosis, therapy or both. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. DSC, FT-IR, NIR, NIR-PCA and NIR-ANOVA for determination of chemical stability of diuretic drugs: impact of excipients

    Directory of Open Access Journals (Sweden)

    Gumieniczek Anna

    2018-03-01

    Full Text Available It is well known that drugs can directly react with excipients. In addition, excipients can be a source of impurities that either directly react with drugs or catalyze their degradation. Thus, binary mixtures of three diuretics, torasemide, furosemide and amiloride with different excipients, i.e. citric acid anhydrous, povidone K25 (PVP, magnesium stearate (Mg stearate, lactose, D-mannitol, glycine, calcium hydrogen phosphate anhydrous (CaHPO4 and starch, were examined to detect interactions. High temperature and humidity or UV/VIS irradiation were applied as stressing conditions. Differential scanning calorimetry (DSC, FT-IR and NIR were used to adequately collect information. In addition, chemometric assessments of NIR signals with principal component analysis (PCA and ANOVA were applied.

  9. Multi-functional bio-compatible luminescent apatite with fatty acid passivated nano silver covers and its theranostics potential

    Science.gov (United States)

    Asha, S.; Nimrodh Ananth, A.; Vanitha Kumari, G.; Prakash, B.; Jose, Sujin P.; Jothi Rajan, M. A.

    2017-09-01

    Europium doped hydroxyapatite (EDA) nanorods with linoleic acid passivated silver ions on their surfaces were synthesized using facile, one-step hydrothermal route. Annealing the samples at 250 °C resulted in formation of ultra-small silver (USS) nanoparticles on the surface by nucleation through diffusion process. EDA exhibited luminescence properties due to the presence of europium ions doped on the calcium sites of hydroxyapatite. These EDA nanorods exhibited a different luminescent behavior in the presence of silver ions and USS nanoparticles. This report also demonstrates excellent biocompatibility and cytotoxicity of EDA nanorods with silver ions towards fibroblast cell lines (F929) and breast cancer cells (MCF-7). Visible and near infra-red (NIR) emissions in EDA, induced by silver ions and USS nanoparticles makes it a potential system for deep tissue imaging applications. The arrangement of USS over the EDA was tunable and hence the selectivity and enhancement of the Eu3+ ions emission can also be tuned. The multifunctional properties of this system such as its active luminescence over a wide range, its cell proliferation towards normal cells and cytotoxicity towards cancer cells shows its potential for application in cancer theranostics.

  10. Influence of pulse-height discrimination threshold for photon counting on the accuracy of singlet oxygen luminescence measurement

    International Nuclear Information System (INIS)

    Lin, Huiyun; Chen, Defu; Wang, Min; Lin, Juqiang; Li, Buhong; Xie, Shusen

    2011-01-01

    Direct measurement of near-infrared (NIR) luminescence around 1270 nm is the golden standard of singlet oxygen ( 1 O 2 ) identification. In this study, the influence of pulse-height discrimination threshold on measurement accuracy of the 1 O 2 luminescence that is generated from the photoirradiation of meso-tetra (N-methyl-4-pyridyl) morphine tetra-tosylate (TMPyP) in aqueous solution was investigated by using our custom-developed detection system. Our results indicate that the discrimination threshold has a significant influence on the absolute 1 O 2 luminescence counts, and the optimal threshold for our detection system is found to be about − 41.2 mV for signal discrimination. After optimization, the derived triplet-state and 1 O 2 lifetimes of TMPyP in aqueous solution are found to be 1.73 ± 0.03 and 3.70 ± 0.04 µs, respectively, and the accuracy of measurement was further independently demonstrated using the laser flash photolysis technique

  11. Luminescence studies of molecular materials

    International Nuclear Information System (INIS)

    Miller, P.F.

    2000-01-01

    Molecular materials have been widely studied for their potential uses in novel semiconductor devices. They occupy the intellectually interesting area between molecular and bulk descriptions of matter, and as such often have unique and useful characteristics. The design and engineering of these structures is inter-disciplinary in its nature, embracing the fields of physics, electrical engineering and both synthetic and physical chemistry. In this thesis luminescence studies of molecular materials will be presented that probe the nature of the excited states in two promising semiconductor systems. Luminescence techniques provide a powerful and sensitive tool in the investigation of kinetic pathways of radiative and non-radiative emission from these samples. This is particularly appropriate here, as the materials being studied are of potential use in electroluminescent devices. The suitability of photoluminescence techniques comes from both the electroluminescence and photoluminescence sharing the same emitting state. The first class of material studied here is an organic semiconducting polymer, cyano-substituted polyphenylenevinylene (CN-PPV). Conjugated polymers combine semiconducting electronic properties with favourable processing properties and offer the possibility of tuning their optical and electronic properties chemically. The cyanosubstitution increases the electron affinity of the polymer backbone, facilitating electron injection in light-emitting diodes. The polymers are soluble in solvents such as toluene and chloroform due the presence of alkoxy sidegroups. CdSe semiconductor nanocrystals are the other class of material characterised in this work. Semiconductor nanocrystals exhibit interesting size-tunable optical properties due to the confinement of the electronic wave functions. Characterisation of samples produced by different synthetic routes has been carried out to demonstrate the advantages of a novel synthetic method in terms of physical and

  12. NIR monitoring of in-service wood structures

    Science.gov (United States)

    Michela Zanetti; Timothy G. Rials; Douglas Rammer

    2005-01-01

    Near infrared spectroscopy (NIRS) was used to study a set of Southern Yellow Pine boards exposed to natural weathering for different periods of exposure time. This non-destructive spectroscopic technique is a very powerful tool to predict the weathering of wood when used in combination with multivariate analysis (Principal Component Analysis, PCA, and Projection to...

  13. Developing and evaluating a multisite and multispecies NIR ...

    African Journals Online (AJOL)

    To elevate NIR from proof-of-concept to a pilot scale, a large multisite, multispecies calibration was developed over iterative cycles to: (1) determine whether KPY in eucalypts can be predicted from a single calibration independent of site and species, and (2) identify the potential limits of accuracy and precision. This paper ...

  14. Solar Energy Delivering Greenhouse with an Integrated NIR filter

    NARCIS (Netherlands)

    Sonneveld, P.J.; Swinkels, G.L.A.M.; Holterman, H.J.; Tuijl, van B.A.J.; Bot, G.P.A.

    2008-01-01

    The scope of this investigation is the design and development of a new type of greenhouse with an integrated filter for rejecting near infrared radiation (NIR) and a solar energy delivery system. Cooled greenhouses are an important issue to cope with the combination of high global radiation and high

  15. VIS/NIR imaging application for honey floral origin determination

    NARCIS (Netherlands)

    Minaei, Saeid; Shafiee, Sahameh; Polder, Gerrit; Moghadam-Charkari, Nasrolah; Ruth, van Saskia; Barzegar, Mohsen; Zahiri, Javad; Alewijn, Martin; Kuś, Piotr M.

    2017-01-01

    Nondestructive methods are of utmost importance for honey characterization. This study investigates the potential application of VIS-NIR hyperspectral imaging for detection of honey flower origin using machine learning techniques. Hyperspectral images of 52 honey samples were taken in

  16. TROPOMI and TROPI: UV/VIS/NIR/SWIR instruments

    NARCIS (Netherlands)

    Levelt, P.F.; Oord, G.H.J. van den; Dobber, M.; Eskes, H.; Weele, M. van; Veefkind, P.; Oss, R. van; Aben, I.; Jongma, R.T.; Landgraf, J.; Vries, J. de; Visser, H.

    2006-01-01

    TROPOMI (Tropospheric Ozone-Monitoring Instrument) is a five-channel UV-VIS-NIR-SWIR non-scanning nadir viewing imaging spectrometer that combines a wide swath (114°) with high spatial resolution (10 × 10 km 2). The instrument heritage consists of GOME on ERS-2, SCIAMACHY on Envisat and, especially,

  17. Tissue oxygenation and haemodynamics measurement with spatially resolved NIRS

    Science.gov (United States)

    Zhang, Y.; Scopesi, F.; Serra, G.; Sun, J. W.; Rolfe, P.

    2010-08-01

    We describe the use of Near Infrared Spectroscopy (NIRS) for the non-invasive investigation of changes in haemodynamics and oxygenation of human peripheral tissues. The goal was to measure spatial variations of tissue NIRS oxygenation variables, namely deoxy-haemoglobin (HHb), oxy-haemoglobin (HbO2), total haemoglobin (HbT), and thereby to evaluate the responses of the peripheral circulation to imposed physiological challenges. We present a skinfat- muscle heterogeneous tissue model with varying fat thickness up to 15mm and a Monte Carlo simulation of photon transport within this model. The mean partial path length and the mean photon visit depth in the muscle layer were derived for different source-detector spacing. We constructed NIRS instrumentation comprising of light-emitting diodes (LED) as light sources at four wavelengths, 735nm, 760nm, 810nm and 850nm and sensitive photodiodes (PD) as the detectors. Source-detector spacing was varied to perform measurements at different depths within forearm tissue. Changes in chromophore concentration in response to venous and arterial occlusion were calculated using the modified Lambert-Beer Law. Studies in fat and thin volunteers indicated greater sensitivity in the thinner subjects for the tissue oxygenation measurement in the muscle layer. These results were consistent with those found using Monte Carlo simulation. Overall, the results of this investigation demonstrate the usefulness of the NIRS instrument for deriving spatial information from biological tissues.

  18. Less transpiration and good quality thanks to NIR-screen

    NARCIS (Netherlands)

    Stanghellini, C.; Kempkes, F.L.K.; Hemming, S.; Jianfeng, D.

    2009-01-01

    Materials or additives for greenhouse cover that reflect or absorb a part of the NIR radiation can decrease the cooling requirement for the greenhouse and increase water use efficiency of the crop. By reducing the ventilation requirement, it might even decrease emissions of carbon dioxide from

  19. Efficient enhancement of bismuth NIR luminescence by aluminum and its mechanism in bismuth doped germanate laser glass

    DEFF Research Database (Denmark)

    Wang, L.P.; Tan, L.L.; Yue, Yuanzheng

    2016-01-01

    As a new member of laser glass family, bismuth-doped glasses have received rising interests due to the application of fiber amplifiers and laser sources in the new spectral range for the next-generation optical communication system. For practical application of the glasses, it must be considered ...

  20. Structural and luminescence studies on Dy{sup 3+} doped lead boro–telluro-phosphate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Selvi, S. [Department of Physics, Gandhigram Rural University, Gandhigram 624302 (India); Venkataiah, G. [Department of Physics, Sri Venkateswara University, Tirupati 517502 (India); Arunkumar, S.; Muralidharan, G. [Department of Physics, Gandhigram Rural University, Gandhigram 624302 (India); Marimuthu, K., E-mail: mari_ram2000@yahoo.com [Department of Physics, Gandhigram Rural University, Gandhigram 624302 (India)

    2014-12-01

    This paper reports results obtained on the structural and luminescence properties of Dy{sup 3+}doped lead boro−telluro-phosphate glasses prepared following the melt quenching technique. FTIR spectra exhibit the presence of B−O vibrations, P−O−P symmetric vibrations and Te−O stretching modes of TeO{sub 3} and TeO{sub 6} units. The metal–ligand bond was identified through UV−vis−NIR absorption spectra and to determine the band tailing parameter, direct and indirect band gap energy of the prepared glasses. The Judd−Ofelt (JO) intensity parameters (Ω{sub 2}, Ω{sub 4} and Ω{sub 6}), experimental and theoretical oscillator strengths were also determined and reported. Luminescence measurements were made to determine the transition probability (A), stimulated emission cross-section (σ{sub P}{sup E}) and branching ratio (β{sub R}) for the transitions that include {sup 4}F{sub 9/2}→{sup 6}H{sub 11/2}, {sup 6}H{sub 13/2} and {sup 6}H{sub 15/2} bands. The effect of Dy{sup 3+} ion concentration on the intensity ratio of yellow to blue emission bands has also been studied and reported. The lifetime corresponding to the {sup 4}F{sub 9/2} level of the title glasses has been found to decrease with the increase in Dy{sup 3+} ion concentration. The chromaticity coordinates (x,y) have been estimated from the luminescence spectra and the suitability of title glasses for white light applications has been analyzed using CIE chromaticity diagram. The variation of optical properties with the concentration of dysprosium oxide content in the glasses have been studied and reported.

  1. Structural and luminescence studies on Dy3+ doped lead boro-telluro-phosphate glasses

    Science.gov (United States)

    Selvi, S.; Venkataiah, G.; Arunkumar, S.; Muralidharan, G.; Marimuthu, K.

    2014-12-01

    This paper reports results obtained on the structural and luminescence properties of Dy3+doped lead boro-telluro-phosphate glasses prepared following the melt quenching technique. FTIR spectra exhibit the presence of B-O vibrations, P-O-P symmetric vibrations and Te-O stretching modes of TeO3 and TeO6 units. The metal-ligand bond was identified through UV-vis-NIR absorption spectra and to determine the band tailing parameter, direct and indirect band gap energy of the prepared glasses. The Judd-Ofelt (JO) intensity parameters (Ω2, Ω4 and Ω6), experimental and theoretical oscillator strengths were also determined and reported. Luminescence measurements were made to determine the transition probability (A), stimulated emission cross-section (σPE) and branching ratio (βR) for the transitions that include 4F9/2→6H11/2, 6H13/2 and 6H15/2 bands. The effect of Dy3+ ion concentration on the intensity ratio of yellow to blue emission bands has also been studied and reported. The lifetime corresponding to the 4F9/2 level of the title glasses has been found to decrease with the increase in Dy3+ ion concentration. The chromaticity coordinates (x,y) have been estimated from the luminescence spectra and the suitability of title glasses for white light applications has been analyzed using CIE chromaticity diagram. The variation of optical properties with the concentration of dysprosium oxide content in the glasses have been studied and reported.

  2. Luminescence investigation of Yb3+/Er3+ codoped single LiYF4 microparticle

    International Nuclear Information System (INIS)

    Gao, Wei; Zheng, Hairong; He, Enjie; Lu, Ying; Gao, Fangqi

    2014-01-01

    Tetragonal phase LiYF 4 :Yb 3+ /Er 3+ microparticles are synthesized via facile hydrothermal method. Single LiYF 4 microparticle is excited with IR laser at 980 nm in a confocal setup, and strong green and weak red emissions are observed. It is found that single LiYF 4 :Yb 3+ /Er 3+ microparticle with sub-structure presents stronger upconversion luminescence emission and smaller intensity ratio of red to green emission than that from LiYF 4 :Yb 3+ /Er 3+ microparticle with no sub-structure. The possible mechanism, the influence of particle size and the existence of EDTA on the upconversion luminescence emission are investigated. The current study suggests that the luminescence observation with single micropaticle can effectively avoid the influence of environment and neighbor particles, which is important for investigating the luminescence properties of micro- or nano-crystals and for extending their application. - Highlights: • Single LiYF 4 microparticle is excited with IR laser at 980 nm in a confocal setup, and strong green and weak red emissions are observed. • Single LiYF 4 microparticle with different morphology exhibits different fluorescence emission intensity and intensity ratio of red to green emission. • The possible mechanism, the influence of particle size and the existence of EDTA on the upconversion emission are investigated

  3. Sample and plume luminescence in fast heavy ion induced desorption

    International Nuclear Information System (INIS)

    Tuszynski, W.; Koch, K.; Hilf, E.R.

    1996-01-01

    The luminescence arising in 252 Cf-fission fragment induced desorption events has been measured using the time-correlated single photon counting technique. Photons emitted from the sample have been guided from a plasma desorption ion source to a photodetector by an optical fibre. Spectra and decay functions have been obtained using thin layers of Coronene or POPOP as samples. The results are strongly dependent on the acceleration field applied for ion extraction. Approximately 10 photons per fission fragment have been produced when applying no accelerating voltage. The results clearly show that these photons come from radiative electronic relaxations of molecules in the solid sample. Considerably more photons per fission fragment have been produced when applying a positive acceleration voltage. The intensity increases almost linearly for acceleration fields below 10 kV/cm and saturates at a nearly 10-fold higher value when compared to no acceleration. The intensity is also affected by the homogeneity of the accelerating field. These additional photons are attributed to radiative electronic relaxations of desorbed neutral molecules in the plume excited by inelastic collisions with accelerated positive ions. No additional photons have been observed when extracting negative ions. The negative ions produced do obviously not hit and/or excite desorbed neutral molecules, presumably due to their specific desorption characteristics. The experimental data have been analyzed by comparing with the cw and time-resolved sample luminescence obtained by optical excitation. The findings demonstrate that valuable information on ion-solid interactions, on specific desorption quantities and on processes in the plume can be obtained by measuring and analyzing the luminescence induced by the impact of high energy primary ions. (orig.)

  4. Luminescence spectra of lead tungstate, spodumene and topaz crystals

    International Nuclear Information System (INIS)

    Ramachandran, Vasuki

    2002-01-01

    A detailed set of thermoluminescence, cathodoluminescence and radioluminescence (TL, CLTL and RLTL) data of lead tungstate, Spodumene and Topaz have been reported for the first time over a wide temperature range from 25 to 500K. Lead tungstate (PbWO 4 ), a widely known scintillating material, gives TL glow peaks which are related to complex defect centres. Doping of this crystal with trivalent rare earth ions (La 3+ , Y 3+ ) reduces the slow component of the emission thereby making it more suitable for its applications. The pentavalent dopants on the other hand, enhance the green emission and quench the blue emission at temperatures 100K. The origin and the irradiation temperature definitely have an effect on the spectrum. No strong relationship could be derived from the dose dependence data. Two less studied minerals, Spodumene and Topaz have also been investigated with the luminescence techniques. The glow peak near 250degC is thought to have originated from Mn 2+ centres. As there are no ESR data available, the assignment of defect centres is rather difficult. Cr + acts as the quencher in green spodumene. Topaz had the same treatment as the other two sets of samples and the defect centre characterisation looks complex as each coloured sample gave different patterns of glow peaks. Cathodoluminescence whilst heating (CLTL) of all these samples showed some unusual features in the form of a luminescence intensity step which is believed to have originated from the presence of ice. Water, in nanoparticle size quantities, is present as a contaminant in the lattice and undergoes a phase transition at 170K from hexagonal to cubic structures. This phase change influences the luminescence efficiency of the host material and is reflected in the spectrum as a discontinuity in intensity. (author)

  5. Evaluation of combined near-IR spectroscopic (NIRS)-IVUS imaging as a means to detect lipid-rich plaque burden in human coronary autopsy specimens

    Science.gov (United States)

    Su, Jimmy L.; Grainger, Stephanie J.; Greiner, Cherry A.; Hendricks, Michael J.; Goode, Meghan M.; Saybolt, Matthew D.; Wilensky, Robert L.; Madden, Sean P.; Muller, James E.

    2016-02-01

    Intracoronary near-infrared spectroscopy (NIRS) can identify lipid in the coronary arteries, but lacks depth resolution. A novel catheter is currently in clinical use that combines NIRS with intravascular ultrasound (IVUS), which provides depth-resolved structural information via the IVUS modality. A measure designated as lipid-rich plaque burden (LRPB) has been proposed as a means to interpret the combined acoustic and optical information of NIRS-IVUS. LRPB is defined as the area created by the intersection of the NIRS lipid-rich arc with the corresponding IVUS-measured plaque burden. We determined the correlation in human coronary autopsy specimens between LRPB, a measure of lipid presence and extent available via intravascular imaging in patients, and the area of lipid-rich plaque as determined by the gold-standard of histology. Fifteen artery segments from 8 human autopsy hearts were imaged with the NIRS-IVUS system (TVC Imaging System, Infraredx Inc., Burlington, MA). Arteries were imaged in a specialty fixture that assured accurate co-registration between imaging and histology. The arteries were then fixed and divided into 2 mm blocks for histological staining. Pathological contouring of lipid-rich areas was performed on the stained thin sections for 54 lipid-rich blocks. Computation of LRPB was performed on transverse NIRS-IVUS frames corresponding to the histologic sections. The quantified LRPB was frequently higher than the lipid-rich plaque area determined by histology, because the region denoted by the EEL and lumen within the NIRS lipid-rich arc is not entirely comprised of lipid. Overall, a moderate to strong correlation (R = 0.73) was found between LRPB determined by NIRS-IVUS imaging and the lipid-rich plaque area determined by histology. LRPB, which can be measured in patients with NIRS-IVUS imaging, corresponds to the amount of lipid-rich plaque in a coronary artery. LRPB should be evaluated in prospective clinical trials for its ability to

  6. 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

  7. 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...

  8. 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

  9. 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

  10. Shape-controlled synthesis of NIR absorbing branched gold nanoparticles and morphology stabilization with alkanethiols

    International Nuclear Information System (INIS)

    Van de Broek, B; Frederix, F; Bonroy, K; Jans, H; Jans, K; Borghs, G; Maes, G

    2011-01-01

    Gold nanoparticles are ideal candidates for clinical applications if their plasmon absorption band is situated in the near infrared region (NIR) of the electromagnetic spectrum. Various parameters, including the nanoparticle shape, strongly influence the position of this absorption band. The aim of this study is to produce stabilized NIR absorbing branched gold nanoparticles with potential for biomedical applications. Hereto, the synthesis procedure for branched gold nanoparticles is optimized varying the different synthesis parameters. By subsequent electroless gold plating the plasmon absorption band is shifted to 747.2 nm. The intrinsic unstable nature of the nanoparticles' morphology can be clearly observed by a spectral shift and limits their use in real applications. However, in this article we show how the stabilization of the branched structure can be successfully achieved by exchanging the initial capping agent for different alkanethiols and disulfides. Furthermore, when using alkanethiols/disulfides with poly(ethylene oxide) units incorporated, an increased stability of the gold nanoparticles is achieved in high salt concentrations up to 1 M and in a cell culture medium. These achievements open a plethora of opportunities for these stabilized branched gold nanoparticles in nanomedicine.

  11. 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)

  12. 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)

  13. [In hospital and mid-term outcome of patients with NIR stent implantation: multicenter ESPORT-NIR registry].

    Science.gov (United States)

    Iñiguez, A; García, E; Seabra, R; Bordes, P; Bethencourt, A; Rigla, J

    2001-05-01

    Despite improvements in the results and techniques of catheter-based revascularization, few studies have evaluated the clinical results of the application of new stent designs. We describe the in-hospital and mid-term outcome of patients undergoing a stent NIR implantation. At least 1 Stent NIR was implanted in 1.004 patients (1.136 lesions) recruited from 50 centers in an international, multicenter, prospective, registry (Spain and Portugal NIR stent registry). Inclusion criteria were objective coronary ischemia related to a severe de novo lesion or first restenosis in native vessels with a reference diameter >= 2.75 mm. The primary end-point was the incidence of major adverse cardiac events within the first 7 months of follow-up. The mean age of the patients was 60 years and 82% were male. Angioplasty was indicated due to unstable angina in 61% of the cases. Stent implantation was successfully achieved in 99.6%. Clinical success (angiographic success without in-hospital major events) was achieved in 98.6% of patients. The rate of angiographic restenosis (> 50% stenosis narrowing) was 16% (CI 95%; 11.7-21.2). The accumulated major cardiac adverse event rate at seven months of follow-up was 8.7%: death (0.9%), acute myocardial infarction (1.2%) and target lesion revascularization (6.6%). In the wide setting of the population included in the ESPORT-NIR registry, stent NIR implantation was a highly effective therapy with a good mid-term clinical and angiographic outcome.

  14. 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)

  15. 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)

  16. Luminescence and structure of manganese(II) halogenides. Pt. 1

    International Nuclear Information System (INIS)

    Oelkrug, D.; Kempny, W.

    1976-01-01

    The luminescence decay times tau and luminescence intensities I of the mixed crystals Mnsub(x)Cdsub(1-x)Hal 2 (Hal = Bl, Br, J; x 6 -octahedra and of some compounds A 2 MnHal 4 (A = large cation) with unlinked MnHal 4 -tetrahedra were investigated between 4.2 K and 295 K. In Osub(h)-coordinated compounds tau decreases with increasing temperature, most strongly in the iodide namely by a factor of five. On the other hand I correspondingly increases to the same extent so that in all cases I x tau = const. That justifies the assumption of quantum yields independent of temperature with the ideal value of one. In Tsub(d)-coordinated compounds tau and I taken as such are constant in the whole temperature range. The Osub(h) - Tsub(d) contrast in tau and I is attributed to oscillator strengths either dependent on temperature or constant. In the case of MnHal 6 coordination the dependency on temperature may be expressed by the function ctgh(hνc/2kT), (νsub(J) = 80, νsub(Br) = 140, νsub(Cl) = 190 cm -1 ), νsup(Hal) very well corresponding with the mean value of the odd optical k = 0 phonons in the CdHal 2 lattice. (orig.) [de

  17. Agglomeration of Luminescent Porous Silicon Nanoparticles in Colloidal Solutions.

    Science.gov (United States)

    Herynková, Kateřina; Šlechta, Miroslav; Šimáková, Petra; Fučíková, Anna; Cibulka, Ondřej

    2016-12-01

    We have prepared colloidal solutions of clusters composed from porous silicon nanoparticles in methanol, water and phosphate-buffered saline (PBS). Even if the size of the nanoclusters is between 60 and 500 nm, due to their highly porous "cauliflower"-like structure, the porous silicon nanoparticles are composed of interconnected nanocrystals having around 2.5 nm in size and showing strong visible luminescence in the orange-red spectral region (centred at 600-700 nm). Hydrophilic behaviour and good solubility of the nanoclusters in water and water-based solutions were obtained by adding hydrogen peroxide into the etching solution during preparation and 16 min long after-bath in hydrogen peroxide. By simple filtration of the solutions with syringe filters, we have extracted smaller nanoclusters with sizes of approx. 60-70 nm; however, these nanoclusters in water and PBS solution (pH neutral) are prone to agglomeration, as was confirmed by zeta potential measurements. When the samples were left at ambient conditions for several weeks, the typical nanocluster size increased to approx. 330-400 nm and then remained stable. However, both freshly filtered and aged samples (with agglomerated porous silicon nanoparticles) of porous silicon in water and PBS solutions can be further used for biological studies or as luminescent markers in living cells.

  18. [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.

  19. 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

  20. 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.

  1. Shed a light of wireless technology on portable mobile design of NIRS

    Science.gov (United States)

    Sun, Yunlong; Li, Ting

    2016-03-01

    Mobile internet is growing rapidly driven by high-tech companies including the popular Apple and Google. The wireless mini-NIRS is believed to deserve a great spread future, while there is sparse report on wireless NIRS device and even for the reported wireless NIRS, its wireless design is scarcely presented. Here we focused on the wireless design of NIRS devices. The widely-used wireless communication standards and wireless communication typical solutions were employed into our NIRS design and then compared on communication efficiency, distance, error rate, low-cost, power consumption, and stabilities, based on the requirements of NIRS applications. The properly-performed wireless communication methods matched with the characteristics of NIRS are picked out. Finally, we realized one recommended wireless communication in our NIRS, developed a test platform on wireless NIRS and tested the full properties on wireless communication. This study elaborated the wireless communication methods specified for NIRS and suggested one implementation with one example fully illustrated, which support the future mobile design on NIRS devices.

  2. Mercaptosuccinic acid-coated NIR-emitting gold nanoparticles for the sensitive and selective detection of Hg2.

    Science.gov (United States)

    Xiong, Xiaodong; Lai, Xiaoqi; Liu, Jinbin

    2018-01-05

    A sensitive fluorescent detection platform for Hg 2+ was constructed based on mercaptosuccinic acid (MSA) coated near-infrared (NIR)-emitting gold nanoparticles (AuNPs). The thiolated mercaptosuccinic acid was employed as both reducing agent and surface coating ligand in a one-step synthesis of NIR-emitting AuNPs (MSA-AuNPs), which exhibited stable fluorescence with the maximum wavelength at 800nm and a wide range of excitation (220-650nm) with the maxima at 413nm. The MSA coated NIR-emitting AuNPs showed a rapid fluorescence quenching toward Hg 2+ over other metal ions with a limit of detection (LOD, 3δ) as low as 4.8nM. The sensing mechanism investigation revealed that the AuNPs formed aggregation due to the "recognition" of Hg 2+ from the MSA, and the resultant strong coupling interaction between Hg 2+ and Au (I) to further quench the fluorescence of the AuNPs, which synergistically resulted in a highly sensitive and selective fluorescence response toward Hg 2+ . This proposed strategy was also demonstrated the possibility to be used for Hg 2+ detection in water samples. Copyright © 2017. Published by Elsevier B.V.

  3. Mercaptosuccinic acid-coated NIR-emitting gold nanoparticles for the sensitive and selective detection of Hg2 +

    Science.gov (United States)

    Xiong, Xiaodong; Lai, Xiaoqi; Liu, Jinbin

    2018-01-01

    A sensitive fluorescent detection platform for Hg2 + was constructed based on mercaptosuccinic acid (MSA) coated near-infrared (NIR)-emitting gold nanoparticles (AuNPs). The thiolated mercaptosuccinic acid was employed as both reducing agent and surface coating ligand in a one-step synthesis of NIR-emitting AuNPs (MSA-AuNPs), which exhibited stable fluorescence with the maximum wavelength at 800 nm and a wide range of excitation (220-650 nm) with the maxima at 413 nm. The MSA coated NIR-emitting AuNPs showed a rapid fluorescence quenching toward Hg2 + over other metal ions with a limit of detection (LOD, 3δ) as low as 4.8 nM. The sensing mechanism investigation revealed that the AuNPs formed aggregation due to the "recognition" of Hg2 + from the MSA, and the resultant strong coupling interaction between Hg2 + and Au (I) to further quench the fluorescence of the AuNPs, which synergistically resulted in a highly sensitive and selective fluorescence response toward Hg2 +. This proposed strategy was also demonstrated the possibility to be used for Hg2 + detection in water samples.

  4. Automatic determination of moisture content in biofuels based on NIR-measurements; Automatisk fukthaltsbestaemning av biobraenslen med NIR-metoden

    Energy Technology Data Exchange (ETDEWEB)

    Berg, Magnus; Wiklund, Sven Erik [AaF-Process AB, Stockholm (Sweden); Karlsson, Mikael; Tryzell, Robert [Bestwood AB, Sundbyberg (Sweden)

    2005-07-01

    The determination of moisture content of biofuel is of large importance for the energy sector. The used methods for moisture determination are based on fuels samples taken from the bulk followed by drying and weighing. To be able to instead determine the moisture content based on a method with good accuracy and with a short response time would be a large improvement. Both for the fuel sampling and the following analysis there are Swedish standards but concerning the fuel sampling the standards are often not followed. The main reason is the difficulties to sample fuel samples from different depth from a delivery. This is one of the reasons that some plants have installed mechanical samplers but the investment cost for these is relatively high. The aim of this project was to investigate the use of the NIR-method for automatic moisture determination in biofuels. Within the project the NIR-method was used to determine the moisture content on withdrawn fuel samples, in addition the possibility to integrate the NIR-method in an automatic sampling system is also described. A large number of samples, in total over 200 samples, have been evaluated with the NIR-method and compared with the reference method, oven drying and gravimetric determination of moisture content. That the NIR-method can be used to determine moisture content in a number of well defined materials have previously been shown. In this report it has moreover been shown that the method can be used under the conditions at the fuel delivery station and for a large spectrum of biofuels. The accuracy that can be achieved with the NIR-method is in the same magnitude as the standard method, i.e. the reference method used for the measurements. Altogether this shows that the NIR-method is an interesting alternative for integration in an automatic measurement system for determination of fuel moisture content in biofuels. To be able to use the NIR-method for automatic determination of fuel moisture content at the

  5. Computational Pipeline for NIRS-EEG Joint Imaging of tDCS-Evoked Cerebral Responses-An Application in Ischemic Stroke.

    Science.gov (United States)

    Guhathakurta, Debarpan; Dutta, Anirban

    2016-01-01

    Transcranial direct current stimulation (tDCS) modulates cortical neural activity and hemodynamics. Electrophysiological methods (electroencephalography-EEG) measure neural activity while optical methods (near-infrared spectroscopy-NIRS) measure hemodynamics coupled through neurovascular coupling (NVC). Assessment of NVC requires development of NIRS-EEG joint-imaging sensor montages that are sensitive to the tDCS affected brain areas. In this methods paper, we present a software pipeline incorporating freely available software tools that can be used to target vascular territories with tDCS and develop a NIRS-EEG probe for joint imaging of tDCS-evoked responses. We apply this software pipeline to target primarily the outer convexity of the brain territory (superficial divisions) of the middle cerebral artery (MCA). We then present a computational method based on Empirical Mode Decomposition of NIRS and EEG time series into a set of intrinsic mode functions (IMFs), and then perform a cross-correlation analysis on those IMFs from NIRS and EEG signals to model NVC at the lesional and contralesional hemispheres of an ischemic stroke patient. For the contralesional hemisphere, a strong positive correlation between IMFs of regional cerebral hemoglobin oxygen saturation and the log-transformed mean-power time-series of IMFs for EEG with a lag of about -15 s was found after a cumulative 550 s stimulation of anodal tDCS. It is postulated that system identification, for example using a continuous-time autoregressive model, of this coupling relation under tDCS perturbation may provide spatiotemporal discriminatory features for the identification of ischemia. Furthermore, portable NIRS-EEG joint imaging can be incorporated into brain computer interfaces to monitor tDCS-facilitated neurointervention as well as cortical reorganization.

  6. 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...

  7. FT-NIR: A Tool for Process Monitoring and More.

    Science.gov (United States)

    Martoccia, Domenico; Lutz, Holger; Cohen, Yvan; Jerphagnon, Thomas; Jenelten, Urban

    2018-03-30

    With ever-increasing pressure to optimize product quality, to reduce cost and to safely increase production output from existing assets, all combined with regular changes in terms of feedstock and operational targets, process monitoring with traditional instruments reaches its limits. One promising answer to these challenges is in-line, real time process analysis with spectroscopic instruments, and above all Fourier-Transform Near Infrared spectroscopy (FT-NIR). Its potential to afford decreased batch cycle times, higher yields, reduced rework and minimized batch variance is presented and application examples in the field of fine chemicals are given. We demonstrate that FT-NIR can be an efficient tool for improved process monitoring and optimization, effective process design and advanced process control.

  8. Near-infrared spectroscopy (NIRS) in a piglet model

    DEFF Research Database (Denmark)

    Clausen, Nicola Groes; Spielmann, Nelly; Ringer, Simone K.

    2017-01-01

    Near-infrared spectroscopy (NIRS) in a piglet model: readings are influenced by the colour of the cover Clausen NG1,2, Spielmann N1,3, Weiss M1,3, Ringer SK4 1Children’s Research Center, University Children’s Hospital of Zurich, Switzerland; 2Department of Anaesthesiology and Intensive Care, Odense....... The rSO2 was measured by placing NIRS sensors in the supra glabellar region. In 12 animals sensors were covered with a uni-coloured pink (P) napkin and a turquoise (T) napkin in a random order (Setting A). In further 13 animals sensors were covered with blue-coloured surgical drape (SD) and a napkin...... with a reddish SantaClaus (SC) motive (Setting B). Uncovered (UC) baseline values were captured and measurements obtained for a period of three minutes. During measurements, the animals were kept in normoterm, normotensive, normoglycaemic and normoxic condition. Inspired oxygen fraction and ventilatory settings...

  9. NIR FRET Fluorophores for Use as an Implantable Glucose Biosensor

    Directory of Open Access Journals (Sweden)

    Majed DWEIK

    2008-12-01

    Full Text Available Development of an in vivo optical sensor requires the utilization of Near Infra Red (NIR fluorophores due to their ability to operate within the biological tissue window. Alexa Fluor 750 (AF750 and Alexa Fluor 680 (AF680 were examined as potential NIR fluorophores for an in vivo fluorescence resonance energy transfer (FRET glucose biosensor. AF680 and AF750 found to be a FRET pair and percent energy transfer was calculated. Next, the tested dye pair was utilized in a competitive binding assay in order to detect glucose. Concanavalin A (Con A and dextran have binding affinity, but in the presence of glucose, glucose displaces dextran due to its higher affinity to Con A than dextran. Finally, the percent signal transfer through porcine skin was examined. The results showed with approximately 4.0 mm porcine skin thickness, 1.98 % of the fluorescence was transmitted and captured by the detector.

  10. What's next in carbon ion radiotherapy at NIRS?

    International Nuclear Information System (INIS)

    Kamada, Tadashi

    2011-01-01

    Since its launch by the National Institute of Radiological Sciences (NIRS) in 1994, cancer therapy using heavy ion beams (carbon ion beams) has been used in approximately 5,500 patients. Accumulated clinical experience has identified certain types of malignant tumors that respond exclusively to this treatment. It has also been made clear that this therapy is capable of treating several other types of cancers safely in a relatively short period of time, effecting remission and/or cure without pain or discomfort in a few days or weeks. We can reasonably state that heavy ion radiotherapy has been established as a safe and effective treatment method. NIRS researchers are continuing to make every effort to develop more effective, efficient, and patient-friendly heavy ion irradiation systems. The result of this research and development is also expected to slash the attendant costs of heavy ion radiotherapy. (author)

  11. NIRS of body and tissues in growing rabbits fed diets with different fat sources and supplemented with Curcuma longa

    Directory of Open Access Journals (Sweden)

    Pier Giorgio Peiretti

    2013-06-01

    Full Text Available A portable Near Infrared Reflectance Spectroscopy (NIRS instrument was applied to 40 growing rabbits to determine body and tissue differences induced by experimental factors. The rabbits were examined at 2 live sites, in 7 warm carcass tissues and in longissimus dorsi muscle samples prepared in ethanol. For this purpose, the method was applied in a bi-factorial experiment concerning the dietary oil source (O (maize vs. palm oil and Curcuma longa (C supplementation (0 and 3 g/kg, respectively. Significant chemical differences emerged for palmitic, oleic and linoleic acids in the longissimus dorsi muscle due to the O factor and for linolenic acid due to the C factor. The NIRS spectra and chemical analyses were elaborated by the Partial Least Squares (PLS method, and the rsquares in cross-validation (R2cv were retained as measure of the unoriented differentiation between the levels of the planned factor for each landmark and fatty acid (FA profile. Multivariate PLS analysis of the FA muscular fat showed that the O factor induced strong differentiation (R2cv: 0.96, while less influence (0.33 was observed for the C factor. The model based on the NIRS radiation of the landmarks clearly shows the O factor effects, not only in the perirenal (0.90 and scapular (0.85 fats, but also in the belly (0.76, liver (0.73 and hind legs (0.72. Whereas the C effects were only expressed in the live animals (ears: 0.66 and abdominal wall: 0.58 and in post-mortem (liver: 0.60. It was concluded that a preliminary NIRS scan of the carcass and of live rabbits can point out the presence of intrinsic experimental effects concerning the lipid metabolism of polyunsaturated FA of the n-6 series (O factor and n-3 series (C factor.

  12. [The NIR spectra based variety discrimination for single soybean seed].

    Science.gov (United States)

    Zhu, Da-Zhou; Wang, Kun; Zhou, Guang-Hua; Hou, Rui-Feng; Wang, Cheng

    2010-12-01

    With the development of soybean producing and processing, the quality breeding becomes more and more important for soybean breeders. Traditional sampling detection methods for soybean quality need to destroy the seed, and does not satisfy the requirement of earlier generation materials sieving for breeding. Near infrared (NIR) spectroscopy has been widely used for soybean quality detection. However, all these applications were referred to mass samples, and they were not suitable for little or single seed detection in breeding procedure. In the present study, the acousto--optic tunable filter (AOTF) NIR spectroscopy was used to measure the single soybean seed. Two varieties of soybean were measured, which contained 60 KENJIANDOU43 seeds and 60 ZHONGHUANG13 seeds. The results showed that NIR spectra combined with soft independent modeling of class analogy (SIMCA) could accurately discriminate the soybean varieties. The classification accuracy for KENJIANDOU43 seeds and ZHONGHUANG13 was 100%. The spectra of single soybean seed were measured at different positions, and it showed that the seed shape has significant influence on the measurement of spectra, therefore, the key point for single seed measurement was how to accurately acquire the spectra and keep their representativeness. The spectra for soybeans with glossy surface had high repeatability, while the spectra of seeds with external defects had significant difference for several measurements. For the fast sieving of earlier generation materials in breeding, one could firstly eliminate the seeds with external defects, then apply NIR spectra for internal quality detection, and in this way the influence of seed shape and external defects could be reduced.

  13. Classification of maize kernels using NIR hyperspectral imaging

    DEFF Research Database (Denmark)

    Williams, Paul; Kucheryavskiy, Sergey V.

    2016-01-01

    NIR hyperspectral imaging was evaluated to classify maize kernels of three hardness categories: hard, medium and soft. Two approaches, pixel-wise and object-wise, were investigated to group kernels according to hardness. The pixel-wise classification assigned a class to every pixel from individual...... and specificity of 0.95 and 0.93). Both feature extraction methods can be recommended for classification of maize kernels on production scale....

  14. Relationship between muscle oxygenation by NIRS and blood lactate

    Energy Technology Data Exchange (ETDEWEB)

    Xu Guodong [School of Physical Education, Jianghan University, Hubei Wuhan 430056 (China); Mao Zongzhen; Ye Yanjie; Lv Kunru, E-mail: xguodong@wipe.edu.cn [School of Health Sciences, Wuhan Institute of Physical Education, Hubei Wuhan 430079 (China)

    2011-01-01

    The aim of the study was to investigate the relationship of muscle oxygenation in term of oxy-hemoglobin concentration change ({Delta}HbO{sub 2}) by NIRS and blood lactate (BLA) in local skeletal muscle and evaluate the capability of NIRS in the research of exercise physiology Twenty-three athlete in the national fin-swimming team took the increasing load training on the power bicycle while their {Delta}HbO{sub 2} and BLA were simultaneously recorded. The initial powers used in the training were set as 100 w for males and 40 w for females. During the experiment, the power kept constant for 3 min before each abrupt increment of 30 w until the limit of the athlete's capability. Statistical analysis and data visualization were performed. Following the increasing load training, {Delta}HbO{sub 2} step-likely increased in the phase of aerobic metabolism but linearly decreased in the phase of anaerobic metabolism. The variation tendency of BLA was the same as {Delta}HbO{sub 2} and the concurrency of crucial turning points between {Delta}HbO{sub 2} and BLA was revealed. This relationship between {Delta}HbO{sub 2} and BLA presented in the increasing load training suggested that {Delta}HbO{sub 2} might be capable for taking the place of the invasively measured parameter BLA. Considering that {Delta}HbO{sub 2} can be noninvasively measured by NIRS, {Delta}HbO{sub 2} has the potential in the evaluation of athletes' physiological function and training effect on the athletes and accordingly NIRS can be well used in this field.

  15. Relationship between muscle oxygenation by NIRS and blood lactate

    International Nuclear Information System (INIS)

    Xu Guodong; Mao Zongzhen; Ye Yanjie; Lv Kunru

    2011-01-01

    The aim of the study was to investigate the relationship of muscle oxygenation in term of oxy-hemoglobin concentration change (ΔHbO 2 ) by NIRS and blood lactate (BLA) in local skeletal muscle and evaluate the capability of NIRS in the research of exercise physiology Twenty-three athlete in the national fin-swimming team took the increasing load training on the power bicycle while their ΔHbO 2 and BLA were simultaneously recorded. The initial powers used in the training were set as 100 w for males and 40 w for females. During the experiment, the power kept constant for 3 min before each abrupt increment of 30 w until the limit of the athlete's capability. Statistical analysis and data visualization were performed. Following the increasing load training, ΔHbO 2 step-likely increased in the phase of aerobic metabolism but linearly decreased in the phase of anaerobic metabolism. The variation tendency of BLA was the same as ΔHbO 2 and the concurrency of crucial turning points between ΔHbO 2 and BLA was revealed. This relationship between ΔHbO 2 and BLA presented in the increasing load training suggested that ΔHbO 2 might be capable for taking the place of the invasively measured parameter BLA. Considering that ΔHbO 2 can be noninvasively measured by NIRS, ΔHbO 2 has the potential in the evaluation of athletes' physiological function and training effect on the athletes and accordingly NIRS can be well used in this field.

  16. 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

  17. Optimization of Temperature Sensing with Polymer-Embedded Luminescent Ru(II Complexes

    Directory of Open Access Journals (Sweden)

    Nelia Bustamante

    2018-02-01

    Full Text Available Temperature is a key parameter in many fields and luminescence-based temperature sensing is a solution for those applications in which traditional (mechanical, electrical, or IR-based thermometers struggle. Amongst the indicator dyes for luminescence thermometry, Ru(II polyazaheteroaromatic complexes are an appealing option to profit from the widespread commercial technologies for oxygen optosensing based on them. Six ruthenium dyes have been studied, engineering their structure for both photostability and highest temperature sensitivity of their luminescence. The most apt Ru(II complex turned out to be bis(1,10-phenanthroline(4-chloro-1,10-phenanthrolineruthenium(II, due to the combination of two strong-field chelating ligands (phen and a substituent with electron withdrawing effect on a conjugated position of the third ligand (4-Clphen. In order to produce functional sensors, the dye has been best embedded into poly(ethyl cyanoacrylate, due to its low permeability to O2, high temperature sensitivity of the indicator dye incorporated into this polymer, ease of fabrication, and excellent optical quality. Thermosensitive elements have been fabricated thereof as optical fiber tips for macroscopic applications (water courses monitoring and thin spots for microscopic uses (temperature measurements in cell culture-on-a-chip. With such dye/polymer combination, temperature sensing based on luminescence lifetime measurements allows 0.05 °C resolution with linear response in the range of interest (0–40 °C.

  18. 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

  19. Synergistically Enhanced Performance of Ultrathin Nanostructured Silicon Solar Cells Embedded in Plasmonically Assisted, Multispectral Luminescent Waveguides

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sung-Min; Dhar, Purnim; Chen, Huandong; Montenegro, Angelo; Liaw, Lauren; Kang, Dongseok; Gai, Boju; Benderskii, Alexander V.; Yoon, Jongseung

    2017-04-12

    Ultrathin silicon solar cells fabricated by anisotropic wet chemical etching of single-crystalline wafer materials represent an attractive materials platform that could provide many advantages for realizing high-performance, low-cost photovoltaics. However, their intrinsically limited photovoltaic performance arising from insufficient absorption of low-energy photons demands careful design of light management to maximize the efficiency and preserve the cost-effectiveness of solar cells. Herein we present an integrated flexible solar module of ultrathin, nanostructured silicon solar cells capable of simultaneously exploiting spectral upconversion and downshifting in conjunction with multispectral luminescent waveguides and a nanostructured plasmonic reflector to compensate for their weak optical absorption and enhance their performance. The 8 μm-thick silicon solar cells incorporating a hexagonally periodic nanostructured surface relief are surface-embedded in layered multispectral luminescent media containing organic dyes and NaYF4:Yb3+,Er3+ nanocrystals as downshifting and upconverting luminophores, respectively, via printing-enabled deterministic materials assembly. The ultrathin nanostructured silicon microcells in the composite luminescent waveguide exhibit strongly augmented photocurrent (~40.1 mA/cm2) and energy conversion efficiency (~12.8%) than devices with only a single type of luminescent species, owing to the synergistic contributions from optical downshifting, plasmonically enhanced upconversion, and waveguided photon flux for optical concentration, where the short-circuit current density increased by ~13.6 mA/cm2 compared with microcells in a nonluminescent medium on a plain silver reflector under a confined illumination.

  20. Comparison of temperature sensing of the luminescent upconversion and ZnCdS nanoparticles

    Science.gov (United States)

    Yanina, I. Yu.; Volkova, E. K.; Sagaidachnaya, E. A.; Konyukhova, J. G.; Kochubey, V. I.; Tuchin, V. V.

    2018-02-01

    The luminescence spectra of upconversion nanoparticles (UCNPs) and ZnCdS nanoparticles (ZnCdSNPs) were measured and analyzed in a wide temperature range: from room to human body and further to a hyperthermic temperature resulting in tissue morphology change. The results show that the luminescence signal of UCNPs and ZnCdSNPs placed within the tissue is reasonably good sensitive to temperature change and accompanied by phase transitions of lipid structures of adipose tissue. The most likely that the multiple phase transitions are associated with the different components of fat cells, such as phospholipids of cell membrane and lipids of fat droplets. In the course of fat cell heating, lipids of fat droplet first transit from a crystalline form to a liquid crystal form and then to a liquid form, which is characterized by much less scattering. The results of phase transitions of lipids were observed as the changes in the slope of the temperature dependence of the intensity of luminescence of the film with nanoparticles embedded into tissue. The obtained results confirm a high sensitivity of the luminescent UCNPs and ZnCdSNPs to the temperature variations within thin tissue samples and show a strong potential for the controllable tissue thermolysis.

  1. Investigation of cross talk in single grain luminescence measurements using an EMCCD camera

    International Nuclear Information System (INIS)

    Gribenski, Natacha; Preusser, Frank; Greilich, Steffen; Huot, Sebastien; Mittelstraß, Dirk

    2015-01-01

    Highly sensitive electron multiplying charges coupled devices (EMCCD) enable the spatial detection of luminescence emissions from samples and have a high potential in single grain luminescence dating. However, the main challenge of this approach is the potential effect of cross talk, i.e. the influence of signal emitted by neighbouring grains, which will bias the information recorded from individual grains. Here, we present the first investigations into this phenomenon when performing single grain luminescence measurements of quartz grains spread over the flat surface of a sample carrier. Dose recovery tests using mixed populations show an important effect of cross talk, even when some distance is kept between grains. This issue is further investigated by focusing just on two grains and complemented by simulated experiments. Creation of an additional rejection criteria based on the brightness properties of the grains is inefficient in selecting grains unaffected by their surroundings. Therefore, the use of physical approaches or image processing algorithms to directly counteract cross talk is essential to allow routine single grain luminescence dating using EMCCD cameras. - Highlights: • We have performed single grain OSL measurements using an EMCCD detector. • Individual equivalent dose cannot be accurately recovered from a mixed dose population. • Grains are influenced by signal emitted by their neighbours during the measurements. • Simulated data confirm the strong effect of this phenomenon. • Increasing the distance between grains or applying brightness criteria are inefficient.

  2. Ar 3p photoelectron sideband spectra in two-color XUV + NIR laser fields

    Science.gov (United States)

    Minemoto, Shinichirou; Shimada, Hiroyuki; Komatsu, Kazma; Komatsubara, Wataru; Majima, Takuya; Mizuno, Tomoya; Owada, Shigeki; Sakai, Hirofumi; Togashi, Tadashi; Yoshida, Shintaro; Yabashi, Makina; Yagishita, Akira

    2018-04-01

    We performed photoelectron spectroscopy using femtosecond XUV pulses from a free-electron laser and femtosecond near-infrared pulses from a synchronized laser, and succeeded in measuring Ar 3p photoelectron sideband spectra due to the two-color above-threshold ionization. In our calculations of the first-order time-dependent perturbation theoretical model based on the strong field approximation, the photoelectron sideband spectra and their angular distributions are well reproduced by considering the timing jitter between the XUV and the NIR pulses, showing that the timing jitter in our experiments was distributed over the width of {1.0}+0.4-0.2 ps. The present approach can be used as a method to evaluate the timing jitter inevitable in FEL experiments.

  3. The application of near infrared spectroscopy (NIR technique for

    Directory of Open Access Journals (Sweden)

    Sandor Barabassy

    2001-06-01

    Full Text Available The production of cow’s milk in Hungary fluctuates by 15-20 % annualy. Surplus milk is dried into powder and can also be converted to modified milk powders using techniques such as ultra filtration. From approximetely 20.000 tonnes, of all milk powder types, 3.000 tonnes, is converted using ultra filtration technology. Multivariable near infrared (NIR calibration was performed on powder mixtures of whole milk, skimmed milk, whey, retenate (protein concentrate and lactose for rapid fat, protein, lactose, water and ash content determination. More than 150 samples were prepared and measured in two NIRS labs (Scottish Agriculture College – SAC – Aberdeen and University of Horticulture and Food Science - UHFS – Budapest. The results obtained from the same samples were compared. The aims of the study were: 1. Rapid quantitative and qualitative determination of mixtures of milk powder products using NIR technique. 2. Comparison of the results achieved in Aberdeen (SAC and Budapest (UHFS institutes. The mass per cent varied between 0.0-2.8% for fat, 0.0-80% for protein, 6.6-100 % for lactose, 0.0-5.0 % for water and 0.0-8.0 % for ash. High correlation coefficients (0.97-0.99 were found for all five components.

  4. Joint attention studies in normal and autistic children using NIRS

    Science.gov (United States)

    Chaudhary, Ujwal; Hall, Michael; Gutierrez, Anibal; Messinger, Daniel; Rey, Gustavo; Godavarty, Anuradha

    2011-03-01

    Autism is a socio-communication brain development disorder. It is marked by degeneration in the ability to respond to joint attention skill task, from as early as 12 to 18 months of age. This trait is used to distinguish autistic from nonautistic. In this study Near infrared spectroscopy (NIRS) is being applied for the first time to study the difference in activation and connectivity in the frontal cortex of typically developing (TD) and autistic children between 4-8 years of age in response to joint attention task. The optical measurements are acquired in real time from frontal cortex using Imagent (ISS Inc.) - a frequency domain based NIRS system in response to video clips which engenders a feeling of joint attention experience in the subjects. A block design consisting of 5 blocks of following sequence 30 sec joint attention clip (J), 30 sec non-joint attention clip (NJ) and 30 sec rest condition is used. Preliminary results from TD child shows difference in brain activation (in terms of oxy-hemoglobin, HbO) during joint attention interaction compared to the nonjoint interaction and rest. Similar activation study did not reveal significant differences in HbO across the stimuli in, unlike in an autistic child. Extensive studies are carried out to validate the initial observations from both brain activation as well as connectivity analysis. The result has significant implication for research in neural pathways associated with autism that can be mapped using NIRS.

  5. Non-contact finger vein acquisition system using NIR laser

    Science.gov (United States)

    Kim, Jiman; Kong, Hyoun-Joong; Park, Sangyun; Noh, SeungWoo; Lee, Seung-Rae; Kim, Taejeong; Kim, Hee Chan

    2009-02-01

    Authentication using finger vein pattern has substantial advantage than other biometrics. Because human vein patterns are hidden inside the skin and tissue, it is hard to forge vein structure. But conventional system using NIR LED array has two drawbacks. First, direct contact with LED array raise sanitary problem. Second, because of discreteness of LEDs, non-uniform illumination exists. We propose non-contact finger vein acquisition system using NIR laser and Laser line generator lens. Laser line generator lens makes evenly distributed line laser from focused laser light. Line laser is aimed on the finger longitudinally. NIR camera was used for image acquisition. 200 index finger vein images from 20 candidates are collected. Same finger vein pattern extraction algorithm was used to evaluate two sets of images. Acquired images from proposed non-contact system do not show any non-uniform illumination in contrary with conventional system. Also results of matching are comparable to conventional system. We developed Non-contact finger vein acquisition system. It can prevent potential cross contamination of skin diseases. Also the system can produce uniformly illuminated images unlike conventional system. With the benefit of non-contact, proposed system shows almost equivalent performance compared with conventional system.

  6. IR and visible luminescence studies in the infrared multiphoton dissociation of 1,2-dibromo-1,1-difluoroethane

    Science.gov (United States)

    Pushpa, K. K.; Kumar, Awadhesh; Vatsa, R. K.; Naik, P. D.; Annaji Rao, K.; Mittal, J. P.; Parthasarathy, V.; Sarkar, S. K.

    1995-07-01

    The infrared multiphoton dissociation of 1,2-dibromo-1,1-difluoroethane gives rise to IR and visible luminescence. Vibrationally excited parent molecules dissociate via two primary channels yielding bromine and vibrationally excited HBr. The strong visible emission observed between 350 to 750 nm has been assigned to electronically excited carbene CF 2Br CH.

  7. 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.

  8. 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

  9. Concurrent fNIRS-fMRI measurement to validate a method for separating deep and shallow fNIRS signals by using multidistance optodes

    Science.gov (United States)

    Funane, Tsukasa; Sato, Hiroki; Yahata, Noriaki; Takizawa, Ryu; Nishimura, Yukika; Kinoshita, Akihide; Katura, Takusige; Atsumori, Hirokazu; Fukuda, Masato; Kasai, Kiyoto; Koizumi, Hideaki; Kiguchi, Masashi

    2015-01-01

    Abstract. It has been reported that a functional near-infrared spectroscopy (fNIRS) signal can be contaminated by extracerebral contributions. Many algorithms using multidistance separations to address this issue have been proposed, but their spatial separation performance has rarely been validated with simultaneous measurements of fNIRS and functional magnetic resonance imaging (fMRI). We previously proposed a method for discriminating between deep and shallow contributions in fNIRS signals, referred to as the multidistance independent component analysis (MD-ICA) method. In this study, to validate the MD-ICA method from the spatial aspect, multidistance fNIRS, fMRI, and laser-Doppler-flowmetry signals were simultaneously obtained for 12 healthy adult males during three tasks. The fNIRS signal was separated into deep and shallow signals by using the MD-ICA method, and the correlation between the waveforms of the separated fNIRS signals and the gray matter blood oxygenation level–dependent signals was analyzed. A three-way analysis of variance (signal depth×Hb kind×task) indicated that the main effect of fNIRS signal depth on the correlation is significant [F(1,1286)=5.34, pdeep and shallow signals, and the accuracy and reliability of the fNIRS signal will be improved with the method. PMID:26157983

  10. 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.

  11. Gold nanoparticles assisted surface enhanced Raman scattering and luminescence of Er{sup 3+} doped zinc–sodium tellurite glass

    Energy Technology Data Exchange (ETDEWEB)

    Ghoshal, S.K.; Awang, Asmahani, E-mail: asmahani_awang@yahoo.com; Sahar, M.R.; Arifin, R.

    2015-03-15

    Significant enhancements in Er{sup 3+} luminescence and Raman intensity mediated via surface plasmon resonance (SPR) of gold (Au) nanoparticles (NPs) embedded zinc–sodium tellurite glass are reported. The observed modifications in the physical and spectroscopic properties are ascribed to the alterations in the glass network. XRD pattern confirms the amorphous nature of prepared glass sample. UV–vis-NIR spectra reveal seven absorption bands. Surface plasmon band is evidenced around 626–630 nm. TEM images manifest the growth of non-spherical Au NPs with average diameter between ∼7.2 nm and 8.6 nm. The visible up-conversion (UC) emission for all samples under 779 nm excitation exhibits three bands centered at 503 nm (green), 546 (green) and 637 nm (red) ascribed to {sup 2}H{sub 11/2}→{sup 4}I{sub 15/2}, {sup 4}S{sub 3/2}→{sup 4}I{sub 15/2} and {sup 4}F{sub 9/2}→{sup 4}I{sub 15/2} transitions. Glass sample with 0.4 mol% Au displaying the highest luminescence intensity with enhancement factor of 3.85 and 3.56 for green bands, and 7.61 for the red band is ascribed to the NPs local field enhancement and energy transfer between rare earth (RE) ions and NPs. FTIR spectra show the vibration of ZnO{sub 4} bonds, Te-O bond in TeO{sub 3} (tp) and TeO{sub 4} (tbp) units and the hydroxyl groups. Raman spectra demonstrate the presence of Er-O and Zn-O bond, anti-symmetric vibrations of Te-O-Te bonds and stretching modes of non-bonded oxygen exists in TeO{sub 3} and TeO{sub 3+1} unit. The amplifications in Raman signals by a factor of 1.62, 1.58, 1.64, 1.68 and 1.69 corresponding to the peak centered at 262 cm{sup −1}, 382 cm{sup −1}, 521 cm{sup −1}, 670 cm{sup −1} and 725 cm{sup −1} are attributed to the contribution of a surface plasmon generating a strong, localized and secondary field. We assert that our glass compositions offer favorable potential to develop solid state lasers and other versatile nanophotonic devices. - Highlights: • Gold

  12. Multistate Luminescent Solar Concentrator "Smart" Windows

    NARCIS (Netherlands)

    Sol, Jeroen A.H.P.; Timmermans, Gilles H.; Breugel, van Abraham J.; Schenning, Albertus P.H.J.; Debije, Michael G.

    2018-01-01

    A supertwist liquid crystalline luminescent solar concentrator (LSC) "smart" window is fabricated which can be switched electrically between three states: one designed for increased light absorption and electrical generation (the "dark" state), one for transparency (the "light" state), and one for

  13. Luminescent Solar Concentrators with Fibre Geometry

    NARCIS (Netherlands)

    Edelenbosch, O.Y.; Fisher, M.; Patrignani, L.; Sark, W.G.J.H.M. van; Chatten, A.J.

    2013-01-01

    The potential of a fibre luminescent solar concentrator has been explored by means of both analytical and ray-tracing techniques. Coated fibres have been found to be more efficient than homogeneously doped fibres, at low absorption. For practical fibres concentration is predicted to be linear

  14. Co-precipitation synthesis and upconversion luminescence ...

    Indian Academy of Sciences (India)

    Introduction. Researches of rare-earth-doped upconversion (UC) materials as fluorescent labels, temperature-sensing probes, solid-state lasers and new generation television screens have recently started to be considered1,2 due to their enhanced luminescent properties induced by the small size. UC process is the gener-.

  15. 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

  16. Probing luminescence centers in Na rich feldspar

    DEFF Research Database (Denmark)

    Prasad, Amit Kumar; Lapp, Torben; Kook, Myung Ho

    2016-01-01

    our understanding of the luminescence mechanisms and recombination sites, in a sample of Na rich plagioclase feldspar (oligoclase). Both the UV and violet–blue emissions show resonant excitations arising from a distribution of energy levels. We propose, contrary to the general understanding...

  17. Studies of positron induced luminescence from polymers

    International Nuclear Information System (INIS)

    Xu, J.; Hulett, L.D. Jr.; Lewis, T.A.; Tolk, N.H.

    1994-01-01

    Light emission from polymers (anthracene dissolved in polystryrene) induced by low-energy positrons and electrons has been studied. Results indicate a clear difference between optical emissions under positron and electron bombardment. The positron-induced luminescence spectrum is believed to be generated by both collisional and annihilation processes

  18. Combustion synthesis and preliminary luminescence studies of ...

    Indian Academy of Sciences (India)

    The polycrystalline sample of LiBaPO4 : Tb3+ (LBPT) was successfully synthesized by solution combustion synthesis and studied for its luminescence characteristics. The thermoluminescence (TL) glow curve of LBPT material consists of two peaks at 204.54 and 251.21°C. The optimum concentration was 0.005 mol to ...

  19. 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

  20. Luminescence of porous silicon doped by erbium

    International Nuclear Information System (INIS)

    Bondarenko, V.P.; Vorozov, N.N.; Dolgij, L.N.; Dorofeev, A.M.; Kazyuchits, N.M.; Leshok, A.A.; Troyanova, G.N.

    1996-01-01

    The possibility of the 1.54 μm intensive luminescence in the silicon dense porous layers, doped by erbium, with various structures is shown. Low-porous materials of both porous type on the p-type silicon and porous silicon with wood-like structure on the n + type silicon may be used for formation of light-emitting structures

  1. ON THE DISTANCE OF THE MAGELLANIC CLOUDS USING CEPHEID NIR AND OPTICAL-NIR PERIOD-WESENHEIT RELATIONS

    International Nuclear Information System (INIS)

    Inno, L.; Bono, G.; Buonanno, R.; Genovali, K.; Matsunaga, N.; Caputo, F.; Laney, C. D.; Marconi, M.; Piersimoni, A. M.; Primas, F.; Romaniello, M.

    2013-01-01

    We present the largest near-infrared (NIR) data sets, JHKs, ever collected for classical Cepheids in the Magellanic Clouds (MCs). We selected fundamental (FU) and first overtone (FO) pulsators, and found 4150 (2571 FU, 1579 FO) Cepheids for Small Magellanic Cloud (SMC) and 3042 (1840 FU, 1202 FO) for Large Magellanic Cloud (LMC). Current sample is 2-3 times larger than any sample used in previous investigations with NIR photometry. We also discuss optical VI photometry from OGLE-III. NIR and optical-NIR Period-Wesenheit (PW) relations are linear over the entire period range (0.0 FU ≤ 1.65) and their slopes are, within the intrinsic dispersions, common between the MCs. These are consistent with recent results from pulsation models and observations suggesting that the PW relations are minimally affected by the metal content. The new FU and FO PW relations were calibrated using a sample of Galactic Cepheids with distances based on trigonometric parallaxes and Cepheid pulsation models. By using FU Cepheids we found a true distance moduli of 18.45 ± 0.02(random) ± 0.10(systematic) mag (LMC) and 18.93 ± 0.02(random) ± 0.10(systematic) mag (SMC). These estimates are the weighted mean over 10 PW relations and the systematic errors account for uncertainties in the zero point and in the reddening law. We found similar distances using FO Cepheids (18.60 ± 0.03(random) ± 0.10(systematic) mag (LMC) and 19.12 ± 0.03(random) ± 0.10(systematic) mag (SMC)). These new MC distances lead to the relative distance, Δμ = 0.48 ± 0.03 mag (FU, log P = 1) and Δμ = 0.52 ± 0.03 mag (FO, log P = 0.5), which agrees quite well with previous estimates based on robust distance indicators.

  2. Identifying irradiated flours by photo-stimulated luminescence technique

    Energy Technology Data Exchange (ETDEWEB)

    Ramli, Ros Anita Ahmad; Yasir, Muhamad Samudi [Faculty of Science and Technology, National University of Malaysia, Bangi, 43000 Kajang, Selangor (Malaysia); Othman, Zainon; Abdullah, Wan Saffiey Wan [Malaysian Nuclear Agency, Bangi 43000 Kajang, Selangor (Malaysia)

    2014-02-12

    Photo-stimulated luminescence (PSL) technique was used in this study to detect gamma irradiation treatment of five types of flours (corn, rice, tapioca, wheat and glutinous rice) at four different doses 0, 0.2, .05 and 1kGy. The signal level was compared with two threshold values (700 and 5000). With the exception of glutinous rice, all irradiated samples produced a strong signal above the upper threshold (5000 counts/60s). All control samples produced negative result with the signals below the lower threshold (700 counts/60s) suggesting that the samples have not been irradiated. Irradiated glutinous rice samples produced intermediate signals (700 - 5000 counts/60s) which were subsequently confirmed using calibrated PSL. The PSL signals remained stable after 90 days of storage. The findings of this study will be useful to facilitate control of food irradiation application in Malaysia.

  3. Luminescent properties of Mn"2"+ doped apatite nanophosphors

    International Nuclear Information System (INIS)

    Ravindranadh, K.; Rao, M. C.; Ravikumar, R. V. S. S. N.

    2016-01-01

    Nanophosphors have been extensively investigated during the last decade due to their various high-performance application potential such as lamp industry, radiation dosimetry, X-ray imaging and colour display. The synthesis of inorganic nanophosphors using both ionizing radiation (IR) or UV light represents very promising technological field. Alkaline earth nanophosphors gathered a lot of attention in past decades because they are considered to be excellent host materials. Transition-metal oxides are well known luminescent emitters in the visible spectral region. Mn"2"+ doped calcium-lithium hydroxyapatite (CLHA) nanophosphors were prepared by mechanochemical synthesis. The prepared samples were characterized by photoluminescence studies. Photoluminescence spectra of Mn"2"+ doped CLHA nanophosphors exhibited green and strong orange emission bands at 534, 577 nm respectively under the excitation wavelength of 365 nm. The CIE chromaticity coordinates were also calculated from emission spectra for Mn"2"+ doped CLHA nanophosphors.

  4. Luminescent properties of Mn2+ doped apatite nanophosphors

    Science.gov (United States)

    Ravindranadh, K.; Ravikumar, R. V. S. S. N.; Rao, M. C.

    2016-05-01

    Nanophosphors have been extensively investigated during the last decade due to their various high-performance application potential such as lamp industry, radiation dosimetry, X-ray imaging and colour display. The synthesis of inorganic nanophosphors using both ionizing radiation (IR) or UV light represents very promising technological field. Alkaline earth nanophosphors gathered a lot of attention in past decades because they are considered to be excellent host materials. Transition-metal oxides are well known luminescent emitters in the visible spectral region. Mn2+ doped calcium-lithium hydroxyapatite (CLHA) nanophosphors were prepared by mechanochemical synthesis. The prepared samples were characterized by photoluminescence studies. Photoluminescence spectra of Mn2+ doped CLHA nanophosphors exhibited green and strong orange emission bands at 534, 577 nm respectively under the excitation wavelength of 365 nm. The CIE chromaticity coordinates were also calculated from emission spectra for Mn2+ doped CLHA nanophosphors.

  5. Identifying irradiated flours by photo-stimulated luminescence technique

    International Nuclear Information System (INIS)

    Ramli, Ros Anita Ahmad; Yasir, Muhamad Samudi; Othman, Zainon; Abdullah, Wan Saffiey Wan

    2014-01-01

    Photo-stimulated luminescence (PSL) technique was used in this study to detect gamma irradiation treatment of five types of flours (corn, rice, tapioca, wheat and glutinous rice) at four different doses 0, 0.2, .05 and 1kGy. The signal level was compared with two threshold values (700 and 5000). With the exception of glutinous rice, all irradiated samples produced a strong signal above the upper threshold (5000 counts/60s). All control samples produced negative result with the signals below the lower threshold (700 counts/60s) suggesting that the samples have not been irradiated. Irradiated glutinous rice samples produced intermediate signals (700 - 5000 counts/60s) which were subsequently confirmed using calibrated PSL. The PSL signals remained stable after 90 days of storage. The findings of this study will be useful to facilitate control of food irradiation application in Malaysia

  6. Synthesis and luminescence properties of erbium silicate thin films

    International Nuclear Information System (INIS)

    Miritello, Maria; Lo Savio, Roberto; Iacona, Fabio; Franzo, Giorgia; Bongiorno, Corrado; Priolo, Francesco

    2008-01-01

    We have studied the structure and the room temperature luminescence of erbium silicate thin films deposited by rf magnetron sputtering. Films deposited on silicon oxide layers are characterized by good structural properties and excellent stability. The optical properties of these films are strongly improved by rapid thermal annealing processes performed in the range of temperature 800-1250 deg. C. In fact through the reduction of the defect density of the material, a very efficient room temperature photoluminescence at 1535 nm is obtained. We have also investigated the influence of the annealing ambient, by finding that treatments in O 2 atmosphere are significantly more efficient in improving the optical properties of the material with respect to processes in N 2 . Upconversion effects become effective only when erbium silicate is excited with high pump powers. The evidence that all Er atoms (about 10 22 cm -3 ) in erbium silicate films are optically active suggests interesting perspectives for optoelectronic applications of this material

  7. Photoinduced Effects in the ZnO Luminescence Spectra

    Science.gov (United States)

    Akopyan, I. Kh.; Labzovskaya, M. E.; Novikov, B. V.; Lisachenko, A. A.; Serov, A. Yu.; Filosofov, N. G.

    2018-02-01

    The effect of intense UV irradiation on the photoluminescence (PL) spectra of ZnO powders and nanocrystalline films obtained by atomic layer deposition (ALD) was investigated. At room temperature, the behavior of the spectra under continuous UV irradiation in multiple vacuum-atmosphere cycles was studied. The changes in the intensities of exciton radiation and radiation in the "green" band region, associated with the phenomena of oxygen photodesorption and photoadsorption, are discussed. In the temperature range of 5-300 K, the effect of strong UV irradiation on the near-edge luminescence spectrum of ZnO films was studied. The nature of a new line arising in the photoluminescence spectra of an irradiated film in the region of emission of bound excitons is discussed.

  8. Luminescent properties of Mn{sup 2+} doped apatite nanophosphors

    Energy Technology Data Exchange (ETDEWEB)

    Ravindranadh, K.; Rao, M. C., E-mail: raomc72@gmail.com [Department of Physics, Andhra Loyola College, Vijayawada-520 008 (India); Ravikumar, R. V. S. S. N. [Department of Physics, Acharya Nagarjuna University, Guntur-522 510 (India)

    2016-05-06

    Nanophosphors have been extensively investigated during the last decade due to their various high-performance application potential such as lamp industry, radiation dosimetry, X-ray imaging and colour display. The synthesis of inorganic nanophosphors using both ionizing radiation (IR) or UV light represents very promising technological field. Alkaline earth nanophosphors gathered a lot of attention in past decades because they are considered to be excellent host materials. Transition-metal oxides are well known luminescent emitters in the visible spectral region. Mn{sup 2+} doped calcium-lithium hydroxyapatite (CLHA) nanophosphors were prepared by mechanochemical synthesis. The prepared samples were characterized by photoluminescence studies. Photoluminescence spectra of Mn{sup 2+} doped CLHA nanophosphors exhibited green and strong orange emission bands at 534, 577 nm respectively under the excitation wavelength of 365 nm. The CIE chromaticity coordinates were also calculated from emission spectra for Mn{sup 2+} doped CLHA nanophosphors.

  9. Enhanced UV luminescence from InAlN quantum well structures using two temperature growth

    International Nuclear Information System (INIS)

    Zubialevich, Vitaly Z.; Sadler, Thomas C.; Dinh, Duc V.; Alam, Shahab N.; Li, Haoning; Pampili, Pietro; Parbrook, Peter J.

    2014-01-01

    InAlN/AlGaN multiple quantum wells (MQWs) emitting between 300 and 350 nm have been prepared by metalorganic chemical vapor deposition on planar AlN templates. To obtain strong room temperature luminescence from InAlN QWs a two temperature approach was required. The intensity decayed weakly as the temperature was increased to 300 K, with ratios I PL (300 K)/I PL (T) max up to 70%. This high apparent internal quantum efficiency is attributed to the exceptionally strong carrier localization in this material, which is also manifested by a high Stokes shift (0.52 eV) of the luminescence. Based on these results InAlN is proposed as a robust alternative to AlGaN for ultraviolet emitting devices. - Highlights: • InAlN quantum wells with AlGaN barriers emitting in near UV successfully grown using quasi-2T approach. • 1 nm AlGaN capping of InAlN quantum wells used to avoid In desorption during temperature ramp to barrier growth conditions. • Strong, thermally resilient luminescence obtained as a result of growth optimization. • Promise of InAlN as an alternative active region for UV emitters demonstrated

  10. 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.

  11. Soil organic carbon and particle sizes mapping using vis–NIR, EC and temperature mobile sensor platform

    DEFF Research Database (Denmark)

    Knadel, Maria; Thomsen, Anton Gårde; Schelde, Kirsten

    2015-01-01

    Soil organic carbon (SOC) is an important parameter in the climate change mitigation strategies and it is crucial for the function of ecosystems and agriculture. Particle size fractions affect strongly the physical and chemical properties of soil and thus also SOC. Conventional analyses of SOC...... predictive ability for SOC was obtained using a fusion of sensor data. The calibration models based on vis–NIR spectra and temperature resulted in RMSECV = 0.14% and R2 = 0.94 in Voulund1. In Voulund2, the combination of EC, temperature and spectral data generated a SOC model with RMSECV = 0.17% and R2 = 0...

  12. Testing strong interaction theories

    International Nuclear Information System (INIS)

    Ellis, J.

    1979-01-01

    The author discusses possible tests of the current theories of the strong interaction, in particular, quantum chromodynamics. High energy e + e - interactions should provide an excellent means of studying the strong force. (W.D.L.)

  13. Optical characterization of luminescent silicon nanocrystals embedded in glass matrices

    Energy Technology Data Exchange (ETDEWEB)

    Debieu, Olivier

    2008-12-16

    Interstellar dust in nebulae and in the Diffuse Interstellar Medium (DISM) of galaxies contains a component which exhibits efficient visible-near infrared luminescence ranging from 500 to 1000 nm, known as Extended Red Emission (ERE). Silicon nanocrystals (nc-Si) are discussed as possible carriers of the ERE. We employed the accelerator facilities of the Institute of Solid State Physics of the University of Jena to implant Si ions into fused silica windows. An excess concentration of silicon atoms is thus produced in the host SiO{sub 2} matrix which, by applying an annealing at 1100 C, condensates to silicon nanoparticles and crystallizes. Although the condensation and crystallization occur after an annealing of one minute,10, 15 the samples were annealed during one hour in order to well-passivate the nc-Si, that means, to reduce effectively the number of Si-dangling bonds at the nc-Si surface that are efficient non-radiative recombination centers. 10, 16 Upon excitation with UV light, most of our nc-Si/SiO{sub 2} samples revealed strong PL. We implanted into our luminescent nc-Si/SiO{sub 2} systems other atomic elements, as for instance magnesium and calcium, which form silicates if their oxide is combined with SiO{sub 2}. The purpose is to simulate the conditions for silicates containing nc-Si. In order to understand the effect of the incorporation of foreign atoms on the PL properties of our nc-Si/SiO{sub 2} systems, we proceeded to similar experiments with Er and Ge. As has been demonstrated by several authors, 17, 18 the presence of nc-Si in a glass matrix enhances considerably the emission of Er{sup 3+} ions at 1.536{mu}m. At the same time, the PL of nc-Si is considerably quenched. Since the solubility of Er in crystalline silicon is about 2 orders of magnitude lower than in SiO{sub 2}, the optically active Er{sup 3+} ions are believed to be localized outside the nc-Si core, demonstrating that ions present in the host SiO{sub 2} matrix influence the PL

  14. Thermally stimulated luminescence and photoluminescence ...

    Indian Academy of Sciences (India)

    2012-01-13

    Jan 13, 2012 ... red to ultraviolet, which depends on the crystal structure of host materials ..... to strong anisotropic nature of the fine structure (fs) transi- tion(s), other .... 39 2065. Pan Shilie, Wu Yicheng, Fu Peizhen, Zhang Guochun, Li Zhihua,.

  15. Unclonable Security Codes Designed from Multicolor Luminescent Lanthanide-Doped Y2O3 Nanorods for Anticounterfeiting.

    Science.gov (United States)

    Kumar, Pawan; Nagpal, Kanika; Gupta, Bipin Kumar

    2017-04-26

    The duplicity of important documents has emerged as a serious problem worldwide. Therefore, many efforts have been devoted to developing easy and fast anticounterfeiting techniques with multicolor emission. Herein, we report the synthesis of multicolor luminescent lanthanide-doped Y 2 O 3 nanorods by hydrothermal method and their usability in designing of unclonable security codes for anticounterfeiting applications. The spectroscopic features of nanorods are probed by photoluminescence spectroscopy. The Y 2 O 3 :Eu 3+ , Y 2 O 3 :Tb 3+ , and Y 2 O 3 :Ce 3+ nanorods emit hypersensitive red (at 611 nm), strong green (at 541 nm), and bright blue (at 438 nm) emissions at 254, 305, and 381 nm, respectively. The SEM and TEM/HRTEM results reveal that these nanorods have diameter and length in the range of 80-120 nm and ∼2-5 μm, respectively. The two-dimensional spatially resolved photoluminescence intensity distribution in nanorods is also investigated by using confocal photoluminescence microscopic technique. Further, highly luminescent unclonable security codes are printed by a simple screen printing technique using luminescent ink fabricated from admixing of lanthanide doped multicolor nanorods in PVC medium. The prospective use of these multicolor luminescent nanorods provide a new opportunity for easily printable, highly stable, and unclonable multicolor luminescent security codes for anti-counterfeiting applications.

  16. Present status of the NIRS-ECR ion source for the HIMAC

    International Nuclear Information System (INIS)

    Kitagawa, A.; Matsushita, H.; Shibuya, S.

    1995-01-01

    The present status of NIRS-ECR ion source for the Heavy Ion Medical Accelerator in Chiba (HIMAC) at National Institute of Radiological Sciences (NIRS) is reported. The beam intensity of the NIRS-ECR was increased by modifications on the magnetic field structure, chamber cooling system, vacuum conductance and the extraction configuration. The output current of Ar 6+ reached 365 eμA after improvements. The good stability, easy operation, and good reproducibility were realized. (author)

  17. SPORT: A new sub-nanosecond time-resolved instrument to study swift heavy ion-beam induced luminescence - Application to luminescence degradation of a fast plastic scintillator

    Science.gov (United States)

    Gardés, E.; Balanzat, E.; Ban-d'Etat, B.; Cassimi, A.; Durantel, F.; Grygiel, C.; Madi, T.; Monnet, I.; Ramillon, J.-M.; Ropars, F.; Lebius, H.

    2013-02-01

    We developed a new sub-nanosecond time-resolved instrument to study the dynamics of UV-visible luminescence under high stopping power heavy ion irradiation. We applied our instrument, called SPORT, on a fast plastic scintillator (BC-400) irradiated with 27-MeV Ar ions having high mean electronic stopping power of 2.6 MeV/μm. As a consequence of increasing permanent radiation damages with increasing ion fluence, our investigations reveal a degradation of scintillation intensity together with, thanks to the time-resolved measurement, a decrease in the decay constant of the scintillator. This combination indicates that luminescence degradation processes by both dynamic and static quenching, the latter mechanism being predominant. Under such high density excitation, the scintillation deterioration of BC-400 is significantly enhanced compared to that observed in previous investigations, mainly performed using light ions. The observed non-linear behaviour implies that the dose at which luminescence starts deteriorating is not independent on particles' stopping power, thus illustrating that the radiation hardness of plastic scintillators can be strongly weakened under high excitation density in heavy ion environments.

  18. Enhanced surface structuring by ultrafast XUV/NIR dual action

    Czech Academy of Sciences Publication Activity Database

    Jakubczak, Krzysztof; Mocek, Tomáš; Chalupský, Jaromír; Lee, G.H.; Kim, T.K.; Park, S.B.; Nam, Ch. H.; Hájková, Věra; Toufarová, Martina; Juha, Libor; Rus, Bedřich

    2011-01-01

    Roč. 13, č. 5 (2011), s. 1-12 ISSN 1367-2630 R&D Projects: GA AV ČR KAN300100702; GA MŠk(CZ) LC528; GA MŠk LA08024; GA ČR GC202/07/J008 Grant - others:AV ČR(CZ) M100100911 Institutional research plan: CEZ:AV0Z10100523 Keywords : XUV beam * ultrafast NIR laser pulses * high-order harmonics * laser-induced periodic surface structures Subject RIV: BH - Optics, Masers, Lasers Impact factor: 4.177, year: 2011 http://iopscience.iop.org/1367-2630/13/5/053049

  19. Correlations between in situ denitrification activity and nir-gene abundances in pristine and impacted prairie streams

    International Nuclear Information System (INIS)

    Graham, David W.; Trippett, Clare; Dodds, Walter K.; O'Brien, Jonathan M.; Banner, Eric B.K.; Head, Ian M.; Smith, Marilyn S.; Yang, Richard K.; Knapp, Charles W.

    2010-01-01

    Denitrification is a process that reduces nitrogen levels in headwaters and other streams. We compared nirS and nirK abundances with the absolute rate of denitrification, the longitudinal coefficient of denitrification (i.e., K den , which represents optimal denitrification rates at given environmental conditions), and water quality in seven prairie streams to determine if nir-gene abundances explain denitrification activity. Previous work showed that absolute rates of denitrification correlate with nitrate levels; however, no correlation has been found for denitrification efficiency, which we hypothesise might be related to gene abundances. Water-column nitrate and soluble-reactive phosphorus levels significantly correlated with absolute rates of denitrification, but nir-gene abundances did not. However, nirS and nirK abundances significantly correlated with K den , as well as phosphorus, although no correlation was found between K den and nitrate. These data confirm that absolute denitrification rates are controlled by nitrate load, but intrinsic denitrification efficiency is linked to nirS and nirK gene abundances. - Denitrification efficiency best correlated to nirS and nirK gene abundances.

  20. A novel CXCR4-targeted near-infrared (NIR) fluorescent probe (Peptide R-NIR750) specifically detects CXCR4 expressing tumors.

    Science.gov (United States)

    Santagata, Sara; Portella, Luigi; Napolitano, Maria; Greco, Adelaide; D'Alterio, Crescenzo; Barone, Maria Vittoria; Luciano, Antonio; Gramanzini, Matteo; Auletta, Luigi; Arra, Claudio; Zannetti, Antonella; Scala, Stefania

    2017-05-31

    C-X-C chemokine receptor 4 (CXCR4) is over-expressed in multiple human cancers and correlates with tumor aggressiveness, poor prognosis and increased risk for distant metastases. Imaging agents for CXCR4 are thus highly desirable. We developed a novel CXCR4-targeted near-infrared (NIR) fluorescent probe (Peptide R-NIR750) conjugating the new developed CXCR4 peptidic antagonist Peptide R with the NIR fluorescent dye VivoTag-S750. Specific CXCR4 binding was obtained in cells overexpressing human CXCR4 (B16-hCXCR4 and human melanoma cells PES43), but not in CXCR4 low expressing cells (FB-1). Ex vivo evaluation demonstrated that PepR-NIR750 specifically detects B16-hCXCR4-derived subcutaneous tumors and lung metastases. Fluorescence Molecular Tomography (FMT) in vivo imaging was performed on mice carrying subcutaneous CHO and CHO-CXCR4 tumors. PepR-NIR750 accumulates only in CXCR4-positive expressing subcutaneous tumors. Additionally, an intense NIR fluorescence signal was detected in PES43-derived lung metastases of nude mice injected with PepR-NIR750 versus mice injected with VivoTag-S750. With a therapeutic intent, mice bearing PES43-derived lung metastases were treated with Peptide R. A the dramatic reduction in PES43-derived lung metastases was detected through a decrease of the PepR-NIR750 signal. PepR-NIR750 is a specific probe for non-invasive detection of human high CXCR4-expressing tumors and metastatic lesion and thus a valuable tool for cancer molecular imaging.

  1. 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.

  2. Luminescence induced by electrons outside zinc oxide nanoparticles driven by intense terahertz pulse trains

    International Nuclear Information System (INIS)

    Nagai, Masaya; Aono, Shingo; Ashida, Masaaki; Kawase, Keigo; Irizawa, Akinori; Isoyama, Goro

    2017-01-01

    We investigated the behaviours of electrons from ZnO nanoparticles via a strong terahertz field. Luminescence from ZnO nanoparticles and surrounding nitrogen molecules was observed when the nanoparticles were irradiated with a terahertz free-electron laser (FEL). These excitations arose from the collision of electrons released via field electron emission with the ZnO nanoparticles and neighbouring nitrogen molecules. The strong excitation frequency dependence of the luminescence reflected the kinetic energy and trajectory of electrons outside the nanoparticles. We also observed spectral changes in the luminescence during macropulses of the FEL, even though the carrier lifetime of the nanoparticles was shorter than the interval between the micropulses. These changes were caused by the nanoparticles becoming charged due to electron emission, resulting in the electrons being re-emitted outside the nanoparticles. The electrons outside the nanoparticles were accelerated more efficiently by the terahertz field than the electrons inside the nanoparticles, and thus the motion of these exterior electrons provided a new excitation path. (paper)

  3. 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

  4. Luminescence properties of a nanoporous freshwater diatom.

    Science.gov (United States)

    Goswami, Bondita; Choudhury, Amarjyoti; Buragohain, Alak K

    2012-01-01

    Freshwater diatom frustules show special optical properties. In this paper we observed luminescence properties of the freshwater diatom Cyclotella meneghiniana. To confirm the morphological properties we present scanning electron microscopy (SEM) images. X-ray diffraction (XRD) studies were carried out to visualize the structural properties of the frustules, confirming that silica present in diatom frustules crystallizes in an α-quartz structure. Study of the optical properties of the silica frustules of diatoms using ultra-violet-visible (UV-vis) spectroscopy and photoluminescence spectroscopy confirmed that the diatom C. meneghiniana shows luminescence in the blue region of the electromagnetic spectrum when irradiated with UV light. This property of diatoms can be exploited to obtain many applications in day-to-day life. Also, using time-resolved photoluminescence spectroscopy (TRPL) it was confirmed that this species of diatom shows bi-exponential decay. Copyright © 2011 John Wiley & Sons, Ltd.

  5. The double luminescence of Color Centers

    International Nuclear Information System (INIS)

    Baldacchini, Giuseppe

    2015-01-01

    An experiment on the luminescence of Color Centers (CCs) carried out in 1987 at the ENEA Laboratories in Frascati had a negative result, but subsequent investigations showed that it was not a failure but rather a discovery of a new phenomenon. Since the coming of lasers, CCs in alkali halides have been successfully used as optically active materials, in particular FA Centers. One of these centers, well known for its medium infrared laser emission at 77 K, cooled further to 2 K emitted in the near infrared and without laser effect. Further investigations showed that the double luminescence was a fundamental property unknown until that time. This important discovery was achieved in Frascati because of the existence since 1973 of a solid and extensive expertise in the field of CCs, which continued over time and later on applied to the modern miniaturized photonic devices [it

  6. 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.

  7. 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.

  8. 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.

  9. Suppression of concentration quenching of Er-related luminescence in Er-doped GaN

    International Nuclear Information System (INIS)

    Chen Shaoqiang; Tomita, Shigeo; Kudo, Hiroshi; Akimoto, Katsuhiro; Dierre, Benjamin; Lee, Woong; Sekiguchi, Takashi

    2010-01-01

    Erbium-doped GaN with different doping concentrations were grown by ammonia-source molecular beam epitaxy. The intra-4f-shell transitions related green luminescence were observed by both photoluminescence (PL) and cathodoluminescence (CL) measurements. It was found that concentration quenching of Er-related luminescence was observed in PL measurements while not in CL measurements. The different excitation and relaxation processes are suggested as the cause of the concentration quenching characteristics between PL and CL. The strong Er-related CL intensity in highly doped GaN demonstrates that high energy excitation is a promising approach to suppress the concentration quenching in Er-doped GaN.

  10. 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)

  11. Thermally stimulated luminescence of KDP activated crystals

    International Nuclear Information System (INIS)

    Tagaeva, B.S.

    2005-01-01

    The aim of this work is the study of recombination luminescence pure and doped by the ions Tl, Se, Pb and Cu of crystals double potassium phosphates (KDP) at irradiation by X-rays. It is established that in the given crystals mechanisms for under-threshold defect formation are realize. The impurity ions results the basic crystal light sum redistribution in the TL peaks. Explanations for some phenomena are given. (author)

  12. Thermal History Using Microparticle Trap Luminescence

    Science.gov (United States)

    2012-06-01

    the size and shape of bacterial or viral agents and dispersed in a burst vessel . After the test, luminescence from the microparticles is measured to...platinum resistor sputtered on 1 nm adhesion layer of chrome, in turn on a 200nm LPCVD nitride; silicon wet -etching makes this a platform suspended...increased to 500°C until combustion occurred (- 7 min). The remaining powder was collected, crushed in a agate mortar, and annealed (typically at 900

  13. 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.

  14. Broadband luminescence in liquid-solid transition

    CERN Document Server

    Achilov, M F; Trunilina, O V

    2002-01-01

    Broadband luminescence (BBL) intensity behavior in liquid-solid transition in polyethyleneglycol-600 has been established. Oscillation of BBL intensity observed in liquid-polycrystal transition are not found to observed in liquid-amorphous solid transition. It is shown that application of the theory of electron state tails to interpretation of BBL spectral properties in liquids demands restriction. BBL spectroscopy may be applied for optimization of preparation of polymers with determined properties. (author)

  15. Ag2O dependent up-conversion luminescence properties in Tm3+/Er3+/Yb3+ co-doped oxyfluorogermanate glasses

    International Nuclear Information System (INIS)

    Hu, Yuebo; Qiu, Jianbei; Song, Zhiguo; Zhou, Dacheng

    2014-01-01

    Up-conversion (UC) luminescence properties of Ag/Tm 3+ /Er 3+ /Yb 3+ co-doped oxyfluorogermanate glasses have been studied to assess the effective role of silver nanoparticles as a sensitizer for Tm 3+ and Er 3+ ions. The X-ray diffraction patterns obtained in this work do not reveal any crystalline phase in the glass. However, the absorption spectra reveal that surface plasmons resonance band of Ag undergoes a distinct split with two maxima and a very broad absorption peak with a background that extends toward the near infrared (NIR) with the increasing of Ag 2 O added concentration. Transmission electron microscope images confirm that silver nanoparticles have been precipitated from matrix glasses and show their distribution, size, and shapes. In addition, changes in UC luminescence intensity of four emission bands 476, 524, 546, and 658 nm corresponding to 1 G 4 → 3 H 6 (Tm 3+ ), ( 2 H 11/2 , 4 S 3/2 ) → 4 I 15/2 (Er 3+ ), and 4 F 9/2 → 4 I 15/2 (Er 3+ ) transitions, respectively, as a function of silver addition to the base composition have been measured under 980 nm excitation. It is confirmed that Ag 2 O added concentration plays an important role in increasing the UC luminescence intensity; however, further increase in Ag 2 O added concentration reduces the intensity

  16. 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.

  17. 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)

  18. Infrared and NIR Raman spectroscopy in medical microbiology

    Science.gov (United States)

    Naumann, Dieter

    1998-04-01

    FTIR and FT-NIR Raman spectra of intact microbial cells are highly specific, fingerprint-like signatures which can be used to (i) discriminate between diverse microbial species and strains, (ii) detect in situ intracellular components or structures such as inclusion bodies, storage materials or endospores, (iii) detect and quantify metabolically released CO2 in response to various different substrate, and (iv) characterize growth-dependent phenomena and cell-drug interactions. The characteristic information is extracted from the spectral contours by applying resolution enhancement techniques, difference spectroscopy, and pattern recognition methods such as factor-, cluster-, linear discriminant analysis, and artificial neural networks. Particularly interesting applications arise by means of a light microscope coupled to the spectrometer. FTIR spectra of micro-colonies containing less than 103 cells can be obtained from colony replica by a stamping technique that transfers micro-colonies growing on culture plates to a special IR-sample holder. Using a computer controlled x, y- stage together with mapping and video techniques, the fundamental tasks of microbiological analysis, namely detection, enumeration, and differentiation of micro- organisms can be integrated in one single apparatus. FTIR and NIR-FT-Raman spectroscopy can also be used in tandem to characterize medically important microorganisms. Currently novel methodologies are tested to take advantage of the complementary information of IR and Raman spectra. Representative examples on medically important microorganisms will be given that highlight the new possibilities of vibrational spectroscopies.

  19. MEMS-based microspectrometer technologies for NIR and MIR wavelengths

    International Nuclear Information System (INIS)

    Schuler, Leo P; Milne, Jason S; Dell, John M; Faraone, Lorenzo

    2009-01-01

    Commercially manufactured near-infrared (NIR) instruments became available about 50 years ago. While they have been designed for laboratory use in a controlled environment and boast high performance, they are generally bulky, fragile and maintenance intensive, and therefore expensive to purchase and maintain. Micromachining is a powerful technique to fabricate micromechanical parts such as integrated circuits. It was perfected in the 1980s and led to the invention of micro electro mechanical systems (MEMSs). The three characteristic features of MEMS fabrication technologies are miniaturization, multiplicity and microelectronics. Combined, these features allow the batch production of compact and rugged devices with integrated intelligence. In order to build more compact, more rugged and less expensive NIR instruments, MEMS technology has been successfully integrated into a range of new devices. In the first part of this paper we discuss the UWA MEMS-based Fabry-Perot spectrometer, its design and issues to be solved. MEMS-based Fabry-Perot filters primarily isolate certain wavelengths by sweeping across an incident spectrum and the resulting monochromatic signal is detected by a broadband detector. In the second part, we discuss other microspectrometers including other Fabry-Perot spectrometer designs, time multiplexing devices and mixed time/space multiplexing devices. (topical review)

  20. Use of FT-NIR Spectroscopy for Bovine Colostrum Analysis

    Directory of Open Access Journals (Sweden)

    P. Navrátilová

    2006-01-01

    Full Text Available Fourier transformation near infrared spectroscopy (FT-NIR in combination with partial least squares (PLS method were used to determine the content of total solids, fat, non-fatty solids, lactose and proteins in bovine colostrum. Spectra of 90 samples were measured in the reflectance mode with a transflectance cuvette in the 10000-4000 cm-1 spectral ranges with 100 scans. Calibration was performed and statistical values of correlation coefficients (R and standard error of calibration values (SEC were computed for total solids (0.986 and 0.919, respectively, fat (0.997 and 0.285, respectively, non-fatty solids (0.995 and 0.451, respectively, lactose (0.934 and 0.285, respectively and protein (0.999 and 0.149, respectively. The calibration models developed were verified by cross validation. It follows from the study that FT-NIR spectroscopy can be used to determine the components of bovine colostrum.

  1. 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 ...

  2. Abortion: Strong's counterexamples fail

    DEFF Research Database (Denmark)

    Di Nucci, Ezio

    2009-01-01

    This paper shows that the counterexamples proposed by Strong in 2008 in the Journal of Medical Ethics to Marquis's argument against abortion fail. Strong's basic idea is that there are cases--for example, terminally ill patients--where killing an adult human being is prima facie seriously morally...

  3. Strong Langmuir turbulence

    International Nuclear Information System (INIS)

    Goldman, M.V.

    1984-01-01

    After a brief discussion of beam-excited Langmuir turbulence in the solar wind, we explain the criteria for wave-particle, three-wave and strong turbulence interactions. We then present the results of a numerical integration of the Zakharov equations, which describe the strong turbulence saturation of a weak (low-density) high energy, bump-on-tail beam instability. (author)

  4. 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

  5. Strongly luminescent monolayered MoS2 prepared by effective ultrasound exfoliation

    Czech Academy of Sciences Publication Activity Database

    Štengl, Václav; Henych, Jiří

    2013-01-01

    Roč. 5, č. 8 (2013), s. 3387-3394 ISSN 2040-3364 Institutional support: RVO:61388980 Keywords : 2-dimensional nanosheets * graphene analogs * quantum dots * photoluminescence * nanotubes Subject RIV: CA - Inorganic Chemistry Impact factor: 6.739, year: 2013

  6. 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.

  7. Luminescence investigation of Yb{sup 3+}/Er{sup 3+} codoped single LiYF{sub 4} microparticle

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Wei; Zheng, Hairong, E-mail: hrzheng@snnu.edu.cn; He, Enjie; Lu, Ying; Gao, Fangqi

    2014-08-01

    Tetragonal phase LiYF{sub 4}:Yb{sup 3+}/Er{sup 3+} microparticles are synthesized via facile hydrothermal method. Single LiYF{sub 4} microparticle is excited with IR laser at 980 nm in a confocal setup, and strong green and weak red emissions are observed. It is found that single LiYF{sub 4}:Yb{sup 3+}/Er{sup 3+} microparticle with sub-structure presents stronger upconversion luminescence emission and smaller intensity ratio of red to green emission than that from LiYF{sub 4}:Yb{sup 3+}/Er{sup 3+} microparticle with no sub-structure. The possible mechanism, the influence of particle size and the existence of EDTA on the upconversion luminescence emission are investigated. The current study suggests that the luminescence observation with single micropaticle can effectively avoid the influence of environment and neighbor particles, which is important for investigating the luminescence properties of micro- or nano-crystals and for extending their application. - Highlights: • Single LiYF{sub 4} microparticle is excited with IR laser at 980 nm in a confocal setup, and strong green and weak red emissions are observed. • Single LiYF{sub 4} microparticle with different morphology exhibits different fluorescence emission intensity and intensity ratio of red to green emission. • The possible mechanism, the influence of particle size and the existence of EDTA on the upconversion emission are investigated.

  8. Prediction of pH and color in pork meat using VIS-NIR Near-infrared Spectroscopy (NIRS

    Directory of Open Access Journals (Sweden)

    Elton Jhones Granemann FURTADO

    2018-06-01

    Full Text Available Abstract The potential of near-infrared spectroscopy (NIRS to predict the physicochemical characteristics of the porcine longissimus dorsi (LD muscle was evaluated in comparison to the standard methods of pH and color for meat quality analysis compared to the pH results with Colorimeter and pH meter. Spectral information from each sample (n = 77 was obtained as the average of 32 successive scans acquired over a spectral range from 400 - 2498 nm with a 2 - nm gap for calibration and validation models. Partial least squares (PLS regression was used for each individual model. An R2 and a residual predictive deviation (RPD of 0.67/1.7, 0.86/2, and 0.76/1.9 were estimated for color parameters L*, a *, and b*, respectively. Final pH had an R2 of 0.67 and a RPD of 1.6. NIRS showed great potential to predict color parameter a * of porcine LD muscle. Further studies with larger samples should help improve model quality.

  9. Visible and NIR image fusion using weight-map-guided Laplacian ...

    Indian Academy of Sciences (India)

    Ashish V Vanmali

    fusion perspective, instead of the conventional haze imaging model. The proposed ... Image dehazing; Laplacian–Gaussian pyramid; multi-resolution fusion; visible–NIR image fusion; weight map. 1. .... Tan's [8] work is based on two assumptions: first, images ... responding colour image, since NIR can penetrate through.

  10. Determination of Aluminium Content in Aluminium Hydroxide Formulation by FT-NIR Transmittance Spectroscopy

    DEFF Research Database (Denmark)

    Lai, Xuxin; Zheng, Yiwu; Søndergaard, Ib

    2007-01-01

    A method for determining the aluminium content of an aluminium hydroxide suspension using near infrared (NIR) transmittance spectroscopy has been developed. Inductively coupled plasma-atomic emission spectroscopy (ICP-AES) was used as reference method. The factors influencing the NIR analysis...... aluminium content in aluminium hydroxide suspension. (c) 2007 Elsevier Ltd. All rights reserved....

  11. A New Framework for the Assessment of Cerebral Hemodynamics Regulation in Neonates Using NIRS

    NARCIS (Netherlands)

    Caicedo, Alexander; Alderliesten, Thomas; Naulaers, Gunnar; Lemmers, Petra; van Bel, Frank; Van Huffel, Sabine

    2016-01-01

    We present a new framework for the assessment of cerebral hemodynamics regulation (CHR) in neonates using near-infrared spectroscopy (NIRS). In premature infants, NIRS measurements have been used as surrogate variables for cerebral blood flow (CBF) in the assessment of cerebral autoregulation (CA).

  12. The role of cell hydration in realization of biological effects of non-ionizing radiation (NIR).

    Science.gov (United States)

    Ayrapetyan, Sinerik

    2015-09-01

    The weak knowledge on the nature of cellular and molecular mechanisms of biological effects of NIR such as static magnetic field, infrasound frequency of mechanical vibration, extremely low frequency of electromagnetic fields and microwave serves as a main barrier for adequate dosimetry from the point of Public Health. The difficulty lies in the fact that the biological effects of NIR depend not only on their thermodynamic characteristics but also on their frequency and intensity "windows", chemical and physical composition of the surrounding medium, as well as on the initial metabolic state of the organism. Therefore, only biomarker can be used for adequate estimation of biological effect of NIR on organisms. Because of the absence of such biomarker(s), organizations having the mission to monitor hazardous effects of NIR traditionally base their instruction on thermodynamic characteristics of NIR. Based on the high sensitivity to NIR of both aqua medium structure and cell hydration, it is suggested that cell bathing medium is one of the primary targets and cell hydration is a biomarker for NIR effects on cells and organisms. The purpose of this article is to present a short review of literature and our own experimental data on the effects of NIR on plants' seeds germination, microbe growth and development, snail neurons and heart muscle, rat's brain and heart tissues.

  13. Single seed NIR as a fast method to predict germination ability in Pak Choi

    DEFF Research Database (Denmark)

    Gislum, René; Deleuran, Lise Christina; Olesen, Merete Halkjær

    2012-01-01

    Single seed NIR has further been tested to determine the applicability for prediction of seed viability in radish (Raphanus sativus L.) seeds and spinach (Spinacia oleracea L.) seeds. The studies show the possibility of using NIR spectroscopy in a seed separating process in the future, provided...

  14. Synthesis, characterization and optical properties of a high NIR reflecting yellow inorganic pigment: Mo6+ doped Y2Ce2O7 as a cool colorant

    International Nuclear Information System (INIS)

    Vishnu, V.S.; Reddy, M.L.P.

    2010-01-01

    Full text: Pigments possessing the ability to confer high solar reflectance have received considerable attention in recent years. The inorganic class of NIR reflective pigments are mainly metal oxides and are primarily employed in two applications: (i) visual camouflage and (ii) reducing heat build up. More than half of the solar radiation consists of near-infrared radiation (52%), the remaining being 43% visible light and 5% ultraviolet radiation. Over heating due to solar radiation negatively affects comfort in the built environment and contributes substantially to electrical consumption for air conditioning and release of green house gases. A pigment which has strong reflections in the NIR region (780-2500 nm) can be referred to as a 'cool' pigment. However, most of the NIR reflective inorganic pigments particularly yellow (eg. cadmium yellow, lead chromate, chrome titanate yellow etc.) contain toxic metals and hence their consumption is being limited. Replacing them with environmentally benign cool pigments that absorb less NIR radiation can yield coatings similar in color, but with higher NIR reflectance. A new class of yellow inorganic pigments possessing high near-infrared reflectance (above 90% at 1100 nm), having the general formula Y 2 Ce 2-x Mo x O 7+δ (x ranges from 0 to 0.5) were synthesized by traditional solid state route. The synthesized samples were characterized by powder X-ray diffraction, Scanning Electron Microscopy, UV-Vis-NIR Diffuse Reflectance Spectroscopy, CIE 1976Lab color scales and TG/DTA analysis. XRD analysis reveals the existence of a major cubic fluorite phase for the pigment samples. The diffuse reflectance analysis of the pigments shows a significant shift in the absorption edge towards higher wavelengths (from 410 nm to 506 nm) for the molybdenum doped samples in comparison with the parent compound. The band gap of the designed pigments changes from 3.01 to 2.44 eV and displays colors varying from ivory white to yellow. The

  15. Annealing time dependent up-conversion luminescence enhancement in magnesium–tellurite glass

    Energy Technology Data Exchange (ETDEWEB)

    Amjad, Raja J., E-mail: rajajunaid25@gmail.com [Advanced Optical Material Research Group, Faculty of Science, Universiti Teknologi Malaysia, Skudai, Johor bahru 81310 (Malaysia); Centre for Solid State Physics, University of the Punjab, QAC, Lahore 54590 (Pakistan); Sahar, M.R.; Ghoshal, S.K.; Dousti, M.R. [Advanced Optical Material Research Group, Faculty of Science, Universiti Teknologi Malaysia, Skudai, Johor bahru 81310 (Malaysia); Riaz, S. [Centre for Solid State Physics, University of the Punjab, QAC, Lahore 54590 (Pakistan); Samavati, A.R.; Arifin, R. [Advanced Optical Material Research Group, Faculty of Science, Universiti Teknologi Malaysia, Skudai, Johor bahru 81310 (Malaysia); Naseem, S. [Centre for Solid State Physics, University of the Punjab, QAC, Lahore 54590 (Pakistan)

    2013-04-15

    Silver nanoparticles (NPs) embedded Er{sup 3+} ions doped magnesium–tellurite glasses are prepared using melt quenching technique. Heat treatment with different time intervals above the glass transition temperature is applied in order to reduce the silver ions (Ag{sup +}) to silver NPs (Ag{sup o}). The transmission electron microscopy (TEM), differential thermal analyses (DTA), UV–vis-NIR absorption spectroscopy and photoluminescence (PL) spectroscopy are used to examine annealing time dependent structural and optical properties. The characteristics temperatures such as glass transition temperature (T{sub g}), crystallization temperature (T{sub c}) and melting temperature (T{sub m}) obtained from DTA for an as prepared sample are 322 °C, 450 °C and 580 °C, respectively. TEM image clearly shows the homogeneous distribution of silver NPs with an average diameter ∼12 nm. The observed localized surface plasmon resonance (LSPR) band is evidenced at 534 nm. Furthermore, the infrared to visible frequency up-conversion (UC) emission under 786 nm excitation exhibits three emission bands centered at 532 nm, 554 nm and 634 nm corresponding to {sup 2}H{sub 11/2}→{sup 4}I{sub 15/2}, {sup 4}S{sub 3/2}→{sup 4}I{sub 15/2} and {sup 4}F{sub 9/2}→{sup 4}I{sub 15/2} transitions of Er{sup 3+}, respectively. Intensity of all the bands is found to enhance by increasing the annealing time up to 24 h. However, further increase in the annealing time duration (∼40 h) reduces the intensity. Enhancement in the luminescence intensity is understood in terms of the local field effect of the silver NPs whereas the quenching is attributed to the energy transfer from Er{sup 3+} ions to silver NPs. -- Highlights: ► Er{sup 3+}-doped silver NPs embedded magnesium–tellurite glasses are prepared. ► TEM confirms the successful precipitation of spherical NPs by heat treatment (HT). ► Luminescence is enhanced due to the growth of NPs after HT up to 24 h. ► With HT>24 h (40 h

  16. 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

  17. Intrinsic and defect related luminescence in double oxide films of Al–Hf–O system under soft X-ray and VUV excitation

    Energy Technology Data Exchange (ETDEWEB)

    Pustovarov, V.A., E-mail: vpustovarov@bk.ru [Ural Federal University, 19 Mira Street, 620002 Yekaterinburg (Russian Federation); Smirnova, T.P.; Lebedev, M.S. [Nikolaev Institute of Inorganic Chemistry, Siberian Branch of Russian Academy of Science, Novosibirsk 630090 (Russian Federation); Gritsenko, V.A. [Institute of Semiconductor Physics, Siberian Branch of Russian Academy of Sciences, Novosibirsk 630090 (Russian Federation); Novosibirsk National Research University, 2 Pirogova Street, 630090 Novosibirsk (Russian Federation); Kirm, M. [Institute of Physics, University of Tartu, 14c Ravila, 50411 Tartu (Estonia)

    2016-02-15

    Low temperature time-resolved luminescence spectra in the region of 2.5–9.5 eV under soft X-ray excitation as well as time-resolved luminescence excitation spectra in the UV–VUV region (3.7–12 eV) of solid solutions Al{sub x}Hf{sub y}O{sub 1−x−y} thin films were investigated. The values of x and Al/Hf ratio were determined from X-ray photoelectron srectroscopy data. Hafnia films and films mixed with alumina were grown in a flow-type chemical vapor deposition reactor with argon as a carrier gas. In addition, pure alumina films were prepared by the atomic layer deposition method. A strong emission band with the peak position at 4.4 eV and with the decay time in the μs-range was revealed for pure hafnia films. The emission peak at 7.74 eV with short nanosecond decay kinetics was observed in the luminescence spectra for pure alumina films. These emission bands were ascribed to the radiative decay of self-trapped excitons (an intrinsic luminescence) in pure HfO{sub 2} and Al{sub 2}O{sub 3} films, respectively. Along with intrinsic host emission, defect related luminescence bands with a larger Stokes shift were observed. In the emission spectra of the solid solution films (x=4; 17; 20 at%) the intrinsic emission bands are quenched and only the luminescence of defects (an anion vacancies) was observed. Based on transformation of the luminescence spectra and ns-luminescence decay kinetics, as well as changes in the time-resolved luminescence and luminescence excitation spectra, the relaxation processes in the films of solid solution are discussed. - Highlights: • Low temperature time−resolved PL spectra were studied in a broad range (1.5−9.5 eV). • We carried out a luminescent control of point defects (anion vacancies) and self−trapped excitons. • We observed photoluminescence of excitons bound on defects. • We observed changes of photoluminescence properties with varying ratio components.

  18. Linear regression models and k-means clustering for statistical analysis of fNIRS data.

    Science.gov (United States)

    Bonomini, Viola; Zucchelli, Lucia; Re, Rebecca; Ieva, Francesca; Spinelli, Lorenzo; Contini, Davide; Paganoni, Anna; Torricelli, Alessandro

    2015-02-01

    We propose a new algorithm, based on a linear regression model, to statistically estimate the hemodynamic activations in fNIRS data sets. The main concern guiding the algorithm development was the minimization of assumptions and approximations made on the data set for the application of statistical tests. Further, we propose a K-means method to cluster fNIRS data (i.e. channels) as activated or not activated. The methods were validated both on simulated and in vivo fNIRS data. A time domain (TD) fNIRS technique was preferred because of its high performances in discriminating cortical activation and superficial physiological changes. However, the proposed method is also applicable to continuous wave or frequency domain fNIRS data sets.

  19. Strong intrinsic motivation

    OpenAIRE

    Dessi, Roberta; Rustichini, Aldo

    2015-01-01

    A large literature in psychology, and more recently in economics, has argued that monetary rewards can reduce intrinsic motivation. We investigate whether the negative impact persists when intrinsic motivation is strong, and test this hypothesis experimentally focusing on the motivation to undertake interesting and challenging tasks, informative about individual ability. We find that this type of task can generate strong intrinsic motivation, that is impervious to the effect of monetary incen...

  20. Bitcoin Meets Strong Consistency

    OpenAIRE

    Decker, Christian; Seidel, Jochen; Wattenhofer, Roger

    2014-01-01

    The Bitcoin system only provides eventual consistency. For everyday life, the time to confirm a Bitcoin transaction is prohibitively slow. In this paper we propose a new system, built on the Bitcoin blockchain, which enables strong consistency. Our system, PeerCensus, acts as a certification authority, manages peer identities in a peer-to-peer network, and ultimately enhances Bitcoin and similar systems with strong consistency. Our extensive analysis shows that PeerCensus is in a secure state...

  1. Strong gravity and supersymmetry

    International Nuclear Information System (INIS)

    Chamseddine, Ali H.; Salam, A.; Strathdee, J.

    1977-11-01

    A supersymmetric theory is constructed for a strong f plus a weak g graviton, together with their accompanying massive gravitinos, by gaugin the gradel 0Sp(2,2,1)x 0Sp(2,2,1) structure. The mixing term between f and g fields, which makes the strong graviton massive, can be introduced through a spontaneous symmetry-breaking mechanism implemented in this note by constructing a non-linear realization of the symmetry group

  2. Nanoparticules multifonctionnelles de vanadate dopées aux terres rares : Marqueurs luminescents, détecteurs d'oxydant et agent de contraste pour l'imagerie à résonance magnétique

    OpenAIRE

    Schoeffel , Markus

    2012-01-01

    Multimodal imaging techniques are of great interest due to the wealth of information they provide. This thesis is devoted to the development and characterization of nanoparticles which can be applied as luminescent probes, for oxidant detection and as contrast agents in magnetic resonance imaging. The work is based on previous studies on Y0.6Eu0.4VO4 nanoparticles which show strong, non-blinking and stable luminescence. Time and space resolved optical oxidant detection is feasible after rever...

  3. 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

  4. 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)

  5. 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).

  6. 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.

  7. 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.

  8. Nanodiamonds and silicon quantum dots: ultrastable and biocompatible luminescent nanoprobes for long-term bioimaging.

    Science.gov (United States)

    Montalti, M; Cantelli, A; Battistelli, G

    2015-07-21

    Fluorescence bioimaging is a powerful, versatile, method for investigating, both in vivo and in vitro, the complex structures and functions of living organisms in real time and space, also using super-resolution techniques. Being poorly invasive, fluorescence bioimaging is suitable for long-term observation of biological processes. Long-term detection is partially prevented by photobleaching of organic fluorescent probes. Semiconductor quantum dots, in contrast, are ultrastable, fluorescent contrast agents detectable even at the single nanoparticle level. Emission color of quantum dots is size dependent and nanoprobes emitting in the near infrared (NIR) region are ideal for low back-ground in vivo imaging. Biocompatibility of nanoparticles, containing toxic elements, is debated. Recent safety concerns enforced the search for alternative ultrastable luminescent nanoprobes. Most recent results demonstrated that optimized silicon quantum dots (Si QDs) and fluorescent nanodiamonds (FNDs) show almost no photobleaching in a physiological environment. Moreover in vitro and in vivo toxicity studies demonstrated their unique biocompatibility. Si QDs and FNDs are hence ideal diagnostic tools and promising non-toxic vectors for the delivery of therapeutic cargos. Most relevant examples of applications of Si QDs and FNDs to long-term bioimaging are discussed in this review comparing the toxicity and the stability of different nanoprobes.

  9. Plasmon-resonant nanorods as multimodal agents for two-photon luminescent imaging and photothermal therapy

    Science.gov (United States)

    Huff, Terry B.; Hansen, Matthew N.; Tong, Ling; Zhao, Yan; Wang, Haifeng; Zweifel, Daniel A.; Cheng, Ji-Xin; Wei, Alexander

    2007-02-01

    Plasmon-resonant gold nanorods have outstanding potential as multifunctional agents for image-guided therapies. Nanorods have large absorption cross sections at near-infrared (NIR) frequencies, and produce two-photon luminescence (TPL) when excited by fs-pulsed laser irradiation. The TPL signals can be detected with single-particle sensitivity, enabling nanorods to be imaged in vivo while passing through blood vessels at subpicomolar concentrations. Furthermore, cells labeled with nanorods become highly susceptible to photothermal damage when irradiated at plasmon resonance, often resulting in a dramatic blebbing of the cell membrane. However, the straightforward application of gold nanorods for cell-specific labeling is obstructed by the presence of CTAB, a cationic surfactant carried over from nanorod synthesis which also promotes their nonspecific uptake into cells. Careful exchange and replacement of CTAB can be achieved by introducing oligoethyleneglycol (OEG) units capable of chemisorption onto nanorod surfaces by in situ dithiocarbamate formation, a novel method of surface functionalization. Nanorods with a dense coating of methyl-terminated OEG chains are shielded from nonspecific cell uptake, whereas nanorods functionalized with folate-terminated OEG chains accumulate on the surface of tumor cells overexpressing their cognate receptor, with subsequent delivery of photoinduced cell damage at low laser fluence.

  10. A beam energy measurement system at NIRS-930 cyclotron

    International Nuclear Information System (INIS)

    Hojo, S.; Honma, T.; Sakamoto, Y.; Miyahara, N.; Okada, T.; Komatsu, K.; Tsuji, N.; Yamada, S.

    2005-01-01

    A beam energy measurement system employing a set of capacitive probes has been developed at NIRS-930 cyclotron. Principle of the measurement is applying a modified-TOF method, so that the two proves are installed at one of the straight section in the beam transport line. Usually they are separated about 5.8 m, which is equivalent to the almost final path length of the beam extracted in the cyclotron. In the measurement, two beam signals are superimposed by adjusting a position of the downstream-probe along the beam direction with watching an oscilloscope screen roughly. In order to determine the beam energy accurately the signals are processed by MCA with suitable electric module. (author)

  11. Rapid NIR determination of alkyl esters in virgin olive oil

    International Nuclear Information System (INIS)

    Cayuela, J.A.

    2017-01-01

    The regulation of The European Union for olive oil and olive pomace established the limit of 35 mg·kg-1 for fatty acids ethyl ester contents in extra virgin olive oils, from grinding seasons after 2016. In this work, predictive models have been established for measuring fatty acid ethyl and methyl esters and to measure the total fatty acid alkyl esters based on near infrared spectroscopy (NIRS), and used successfully for this purpose. The correlation coefficients from the external validation exercises carried out with these predictive models ranged from 0.84 to 0.91. Different classification tests using the same models for the thresholds 35 mg·kg-1 for fatty acid ethyl esters and 75 mg·kg-1 for fatty acid alkyl esters provided success percentages from 75.0% to 95.2%. [es

  12. Measurement of quadriceps endurance by fNIRS

    Science.gov (United States)

    Erdem, Devrim; Şayli, Ömer; Karahan, Mustafa; Akin, A.

    2006-02-01

    In this paper, the changes in muscle deoxygenation trends during a sustained isometric quadriceps (chair squat/half squat) endurance exercise were evaluated among twelve male subjects and the relationship between muscle oxygenation and endurance times was investigated by means of functional near-infrared spectroscopy (fNIRS). Neuromuscular activation and predictions of muscle performance decrements during extended fatiguing task was investigated by means of surface electromyography (sEMG). The results of the study showed that in the subjects who maintained exercise longer than five minutes (group 1), mean Hb recovery time (33 [sec.]) was 37.4% less than the others (group 2, 52.7 [sec.]). Also mean HbO II decline amplitude (2.53 [a.u.] in group 1 and 2.07 [a.u.] in group 2) and oxy decline amplitude (8.4 [a.u.] in group 1 and 3.04 [a.u.] in group 2) in the beginning of squat exercise are found to be 22.6% and 176.9% bigger in these group. For the EMG parameters, mean slope of MNF and MDF decline are found to be 57.5% and 42.2% bigger in magnitude in group 2 which indicates higher degree of decrement in mean and median frequencies although their mean squat duration time is less. This indicates higher index of fatigue for this group. It is concluded that training leads to altered oxygenation and oxygen extraction capability in the exercising muscle and investigated fNIRS parameters could be used for endurance evaluation.

  13. Luminescence variations in europium-doped silicon-substituted hydroxyapatite nanobiophosphor via three different methods

    Energy Technology Data Exchange (ETDEWEB)

    Thang, Cao Xuan; Pham, Vuong-Hung, E-mail: vuong.phamhung@hust.edu.vn

    2015-07-15

    Highlights: • Europium doped silicon-substituted hydroxyapatite was synthesized by wet chemical synthesis method. • Morphology of nanoparticles depended on the synthesized method. • Photoluminescence intensity of the sample increases with the increasing of Si substitutions, Eu dopants and thermal annealing. - Abstract: This paper reports the first attempt for the synthesis of europium-doped Si-substituted hydroxyapatite (HA) nanostructure to achieve strong and stable luminescence of nanobiophosphor, particularly, by addition of different Eu dopants, Si substitutions, and application of optimum annealing temperatures of up to 1000 °C. The nanobiophosphor was synthesized by the coprecipitation, microwave, and hydrothermal methods. The nanoparticles demonstrated a nanowire to a spindle-like morphology, which was dependent on the method of synthesis. The photoluminescence (PL) intensity of the sample increases with the increase in Si substitutions and Eu dopants. The luminescent nanoparticles also showed the typical luminescence of Eu{sup 3+} centered at 610 nm, which was more efficient for the annealed Eu-doped Si-HA nanoparticles than for the as-synthesized nanoparticles. Among the different synthesis methods, the hydrothermal method reveals the best light emission represented by high PL intensity and narrow PL spectra. These results suggest the potential application of Eu-doped Si-HA in stable and biocompatible nanophosphors for light emission and nanomedicine.

  14. 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

  15. 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)

  16. Filtering natural light at the greenhouse covering - better greenhouse climate and higher production by filtering out NIR?

    NARCIS (Netherlands)

    Hemming, S.; Kempkes, F.; Braak, van der N.; Dueck, T.A.; Marissen, A.

    2006-01-01

    Wageningen UR investigated the potentials of several NIR-filtering methods to be applied in Dutch horticulture. NIR-filtering can be done by the greenhouse covering or by internal or external moveable screens. The objective of this investigation was to quantify the effect of different NIR-filtering

  17. Synthesis of high luminescent carbon nanoparticles

    Science.gov (United States)

    Gvozdyuk, Alina A.; Petrova, Polina S.; Goryacheva, Irina Y.; Sukhorukov, Gleb B.

    2017-03-01

    In this article we report an effective and simple method for synthesis of high luminescent carbon nanodots (CDs). In our work as a carbon source sodium dextran sulfate (DS) was used because it is harmless, its analogs are used in medicine as antithrombotic compounds and blood substitutes after hemorrhage. was used as a substrate We investigated the influence of temperature parameters of hydrothermal synthesis on the photoluminescence (PL) intensity and position of emission maxima. We discovered that the PL intensity can be tuned by changing of synthesis temperature and CD concentration.

  18. Circularly polarized luminescence of syndiotactic polystyrene

    Science.gov (United States)

    Rizzo, Paola; Abbate, Sergio; Longhi, Giovanna; Guerra, Gaetano

    2017-11-01

    Syndiotactic polystyrene (s-PS) films, when crystallized from the amorphous state by temporary sorption of non-racemic guest molecules (like carvone) not only exhibit unusually high optical activity, both in the UV-Visible and Infrared ranges, but also present circularly polarized luminescence (CPL) with high dissymmetry ratios (g = ΔI/I values in the range 0.02-0.03). Experimental evidences provide support, rather than to the usual molecular circular dichroism, to a supramolecular chiral optical response being extrinsic to the site of photon absorption and emission, possibly associated with a helical morphology of s-PS crystallites.

  19. Luminescent properties of praseodymium in some fluorides

    International Nuclear Information System (INIS)

    Potapov, A.S.; Rodnyj, P.A.; Mikhrin, S.B.; Magunov, I.R.

    2005-01-01

    Influence of diverse factors on efficiency of the Pr 3+ cascade emission in BaF 2 : Pr and SrAlF 5 : Pr. The effect of the environment of the luminescence center on the mutual position of the lowest 5d and the 4f level 1 S 0 of Pr 3+ ion is considered. PrF 3 clustering in BaF 2 is observed at a high praseodymium concentration. The promising potential of magnesium as a charge compensator for praseodymium in SrAlF 5 is demonstrated [ru

  20. Luminescent solar concentrators with fiber geometry.

    Science.gov (United States)

    Edelenbosch, Oreane Y; Fisher, Martyn; Patrignani, Luca; van Sark, Wilfried G J H M; Chatten, Amanda J

    2013-05-06

    The potential of a fibre luminescent solar concentrator has been explored by means of both analytical and ray-tracing techniques. Coated fibres have been found to be more efficient than homogeneously doped fibres, at low absorption. For practical fibres concentration is predicted to be linear with fibre length. A 1 m long, radius 1 mm, fibre LSC doped with Lumogen Red 305 is predicted to concentrate the AM1.5 g spectrum up to 1100 nm at normal incidence by ~35 x. The collection efficiency under diffuse and direct irradiance in London has been analysed showing that, even under clear sky conditions, in winter the diffuse contribution equals the direct.

  1. Research Update: Luminescence in lead halide perovskites

    Directory of Open Access Journals (Sweden)

    Ajay Ram Srimath Kandada

    2016-09-01

    Full Text Available Efficiency and dynamics of radiative recombination of carriers are crucial figures of merit for optoelectronic materials. Following the recent success of lead halide perovskites in efficient photovoltaic and light emitting technologies, here we review some of the noted literature on the luminescence of this emerging class of materials. After outlining the theoretical formalism that is currently used to explain the carrier recombination dynamics, we review a few significant works which use photoluminescence as a tool to understand and optimize the operation of perovskite based optoelectronic devices.

  2. Optically stimulated luminescence dating of rock surfaces

    DEFF Research Database (Denmark)

    Sohbati, Reza

    There are many examples of rock surfaces, rock art and stone structures whose ages are of great importance to the understanding of various phenomena in geology, climatology and archaeology. Optically stimulated luminescence (OSL) dating is a well-established chronological tool that has successfully...... to include the effects of the environmental dose rate. By fitting the model to the dose-depth variation from a single clast, four events (two light exposures of different durations each followed by a burial period) in the history of a single cobble are identified and quantified. However, the use of model...

  3. 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

  4. Covalently Assembled NIR Nanoplatform for Simultaneous Fluorescence Imaging and Photodynamic Therapy of Cancer Cells

    NARCIS (Netherlands)

    Liu, Kai; Liu, Xiaomin; Zeng, Qinghui; Zhang, Youlin; Tu, Langping; Liu, Tao; Kong, Xianggui; Wang, Yinghui; Cao, Feng; Lambrechts, Saskia A. G.; Aalders, Maurice C. G.; Zhang, Hong

    2012-01-01

    A highly efficient multifunctional nanoplatform for simultaneous upconversion luminescence (UCL) Imaging and photodynamic therapy has been developed on the basis of selective energy transfer from multicolor luminescent NaYF4:Yb3+,Er3+ upconversion nanoparticles (UCNPs) to photosensitizers (PS).

  5. Covalently assembled NIR nanoplatform for simultaneous fluorescence imaging and photodynamic therapy of cancer cells

    NARCIS (Netherlands)

    Liu, K.; Liu, X.; Zeng, Q.; Zhang, Y.; Tu, L.; Liu, T.; Kong, X.; Wang, Y.; Cao, F.; Lambrechts, S.A.G.; Aalders, M.C.G.; Zhang, H.

    2012-01-01

    A highly efficient multifunctional nanoplatform for simultaneous upconversion luminescence (UCL) imaging and photodynamic therapy has been developed on the basis of selective energy transfer from multicolor luminescent NaYF4:Yb3+,Er3+ upconversion nanoparticles (UCNPs) to photosensitizers (PS).

  6. Spectroscopy and enhanced frequency upconversion in Nd3+-Yb3+ codoped TPO glasses: energy transfer and NIR to visible upconverter

    Science.gov (United States)

    Azam, Mohd; Rai, Vineet Kumar; Mohanty, Deepak Kumar

    2017-09-01

    TeO2-Pb3O4 (TPO) glasses codoped with Nd3+ and Yb3+ ions have been fabricated by conventional melting technique. The absorption, emission and excitation spectra of the samples have been recorded. The optical band gap in both the doped/codoped glasses is found to be ˜3.31 eV. Judd-Ofelt analysis has been carried out by using the absorption spectrum of 0.8 mol% Nd3+ doped glass to determine the radiative properties viz radiative transition probabilities, branching ratios, radiative lifetimes, quality factor and emission cross sections of some emitting levels for Nd3+ ions. The radiative transition probability for the 4G7/2 → 4I9/2 transition (˜1926 Hz) is found to be maximum compared to other 4G5/2 → 4I9/2 (˜1622 Hz) and 4F5/2 → 4I9/2 (˜865 Hz) transitions. Upconversion (UC) luminescence of the samples has been examined by the 980 nm CW diode laser excitation. Effect of addition of Yb3+ ions in the Nd3+ doped glasses on UC emission intensity has been discussed. The UC emission intensity corresponding to the green, red and NIR bands in the codoped glass has been enhanced by ˜17, ˜12 and ˜42 times as compared to that of the Nd3+ singly doped glass. The quantum efficiency for the 4G7/2 level is found to be ˜32%. The nephelauxetic ratio, bonding parameter and covalency of Nd3+ ions have been found positive which represents the covalent bonding between Nd3+ ion and oxygen atom. The colour tunability from yellowish-green to dominant green region has been obtained in the optimized codoped TPO glass.

  7. Strongly interacting Fermi gases

    Directory of Open Access Journals (Sweden)

    Bakr W.

    2013-08-01

    Full Text Available Strongly interacting gases of ultracold fermions have become an amazingly rich test-bed for many-body theories of fermionic matter. Here we present our recent experiments on these systems. Firstly, we discuss high-precision measurements on the thermodynamics of a strongly interacting Fermi gas across the superfluid transition. The onset of superfluidity is directly observed in the compressibility, the chemical potential, the entropy, and the heat capacity. Our measurements provide benchmarks for current many-body theories on strongly interacting fermions. Secondly, we have studied the evolution of fermion pairing from three to two dimensions in these gases, relating to the physics of layered superconductors. In the presence of p-wave interactions, Fermi gases are predicted to display toplogical superfluidity carrying Majorana edge states. Two possible avenues in this direction are discussed, our creation and direct observation of spin-orbit coupling in Fermi gases and the creation of fermionic molecules of 23Na 40K that will feature strong dipolar interactions in their absolute ground state.

  8. A strong comeback

    International Nuclear Information System (INIS)

    Marier, D.

    1992-01-01

    This article presents the results of a financial rankings survey which show a strong economic activity in the independent energy industry. The topics of the article include advisor turnover, overseas banks, and the increase in public offerings. The article identifies the top project finance investors for new projects and restructurings and rankings for lenders

  9. From Antenna to Assay: Lessons Learned in Lanthanide Luminescence

    Energy Technology Data Exchange (ETDEWEB)

    Moore, Evan; Samuel, Amanda; Raymond, Kenneth

    2008-09-25

    these chromophores as a tool to guide ligand design. Additionally we have investigated chiral IAM ligands that yield Tb(III) complexes possessing both high quantum yield values and strong circularly polarized luminescence (CPL) activity. To efficiently sensitize Eu(III) emission, we have utilized ligands based on the 1-hydroxypyridin-2-one (1,2-HOPO) chelate, which are remarkable since they combine both excellent photophysical properties in addition to exceptional aqueous stabilities. A more compete understanding of this chromophore has been achieved by combining low temperature phosphorescence measurements with the same TD-DFT approach used with the IAM system. Also, Eu(III) complexes with strong CPL activity have been obtained through preparation of chiral 1,2-HOPO ligands. Using the unique spectroscopic properties of Eu(III), we have also undertaken the kinetic analysis of radiative and non-radiative decay pathways for a series of complexes, which has highlighted the importance of the metal ion symmetry on the ensuing photophysical properties. Lastly, the commercial development of a Tb-IAM compound that offers improved performance in the common HTRF platform and has the potential to vastly improve the sensitivity of measurements carried out using this technique is presented.

  10. 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

  11. ZnO Luminescence and scintillation studied via photoexcitation, X-ray excitation, and gamma-induced positron spectroscopy

    Science.gov (United States)

    Ji, J.; Colosimo, A. M.; Anwand, W.; Boatner, L. A.; Wagner, A.; Stepanov, P. S.; Trinh, T. T.; Liedke, M. O.; Krause-Rehberg, R.; Cowan, T. E.; Selim, F. A.

    2016-08-01

    The luminescence and scintillation properties of ZnO single crystals were studied by photoluminescence and X-ray-induced luminescence (XRIL) techniques. XRIL allowed a direct comparison to be made between the near-band emission (NBE) and trap emissions providing insight into the carrier recombination efficiency in the ZnO crystals. It also provided bulk luminescence measurements that were not affected by surface states. The origin of a green emission, the dominant trap emission in ZnO, was then investigated by gamma-induced positron spectroscopy (GIPS) - a unique defect spectroscopy method that enables positron lifetime measurements to be made for a sample without contributions from positron annihilation in the source materials. The measurements showed a single positron decay curve with a 175 ps lifetime component that was attributed to Zn vacancies passivated by hydrogen. Both oxygen vacancies and hydrogen-decorated Zn vacancies were suggested to contribute to the green emission. By combining scintillation measurements with XRIL, the fast scintillation in ZnO crystals was found to be strongly correlated with the ratio between the defect luminescence and NBE. This study reports the first application of GIPS to semiconductors, and it reveals the great benefits of the XRIL technique for the study of emission and scintillation properties of materials.

  12. Detecting infrared luminescence and non-chemical signaling of living cells: single cell mid-IR spectroscopy in cryogenic environments

    Science.gov (United States)

    Pereverzev, Sergey

    2017-02-01

    Many life-relevant interaction energies are in IR range, and it is reasonable to believe that some biochemical reactions inside cells can results in emission of IR photons. Cells can use this emission for non-chemical and non-electrical signaling. Detecting weak infrared radiation from live cells is complicated because of strong thermal radiation background and absorption of radiation by tissues. A microfluidic device with live cells inside a vacuum cryogenic environment should suppress this background, and thereby permit observation of live cell auto-luminescence or signaling in the IR regime. One can make IR-transparent windows not emitting in this range, so only the cell and a small amount of liquid around it will emit infrared radiation. Currently mid-IR spectroscopy of single cells requires the use of a synchrotron source to measure absorption or reflection spectra. Decreasing of thermal radiation background will allow absorption and reflection spectroscopy of cells without using synchrotron light. Moreover, cell auto-luminescence can be directly measured. The complete absence of thermal background radiation for cryogenically cooled samples allows the use IR photon-sensitive detectors and obtaining single molecule sensitivity in IR photo-luminescence measurements. Due to low photon energies, photo-luminescence measurements will be non-distractive for pressures samples. The technique described here is based upon US patent 9366574.

  13. 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.

  14. Highly Sensitive Luminescence Assessment of Bile Acid Using a Balofloxacin-Europium(III) Probe in Micellar Medium

    International Nuclear Information System (INIS)

    Cai, Huan; Zhao, Fang; Si, Hailin; Zhang, Shuaishuai; Wang, Chunchun; Qi, Peirong

    2012-01-01

    A novel and simple method of luminescence enhancement effect for the determination of trace amounts of bile acid was proposed. The procedure was based on the luminescence intensity of the balofloxacin-europium(III) complex that could be strongly enhanced by bile acid in the presence of sodium dodecyl benzene sulfonate (SDBS). Under the optimum conditions, the enhanced luminescence intensity of the system exhibited a good linear relationship with the bile acid concentration in the range 5.0 Χ 10 -9 - 7.0 Χ 10 -7 mol L -1 with a detection limit of 1.3 Χ 10 -9 mol L.1 (3σ). The relative standard deviation (RSD) was 1.7% (n = 11) for 5.0 Χ 10 -8 mol L -1 bile acid. The applicability of the method to the determination of bile acid was demonstrated by investigating the effect of potential interferences and by analyzing human serum and urine samples. The possible enhancement mechanism of luminescence intensity in balofloxacin-europium(III)-bile acid-SDBS system was also discussed briefly

  15. Study on feasibility of determination of glucosamine content of fermentation process using a micro NIR spectrometer.

    Science.gov (United States)

    Sun, Zhongyu; Li, Can; Li, Lian; Nie, Lei; Dong, Qin; Li, Danyang; Gao, Lingling; Zang, Hengchang

    2018-08-05

    N-acetyl-d-glucosamine (GlcNAc) is a microbial fermentation product, and NIR spectroscopy is an effective process analytical technology (PAT) tool in detecting the key quality attribute: the GlcNAc content. Meanwhile, the design of NIR spectrometers is under the trend of miniaturization, portability and low-cost nowadays. The aim of this study was to explore a portable micro NIR spectrometer with the fermentation process. First, FT-NIR spectrometer and Micro-NIR 1700 spectrometer were compared with simulated fermentation process solutions. The R c 2 , R p 2 , RMSECV and RMSEP of the optimal FT-NIR and Micro-NIR 1700 models were 0.999, 0.999, 3.226 g/L, 1.388 g/L and 0.999, 0.999, 1.821 g/L, 0.967 g/L. Passing-Bablok regression method and paired t-test results showed there were no significant differences between the two instruments. Then the Micro-NIR 1700 was selected for the practical fermentation process, 135 samples from 10 batches were collected. Spectral pretreatment methods and variables selection methods (BiPLS, FiPLS, MWPLS and CARS-PLS) for PLS modeling were discussed. The R c 2 , R p 2 , RMSECV and RMSEP of the optimal GlcNAc content PLS model of the practical fermentation process were 0.994, 0.995, 2.792 g/L and 1.946 g/L. The results have a positive reference for application of the Micro-NIR spectrometer. To some extent, it could provide theoretical supports in guiding the microbial fermentation or the further assessment of bioprocess. Copyright © 2018. Published by Elsevier B.V.

  16. Luminescence optically stimulated: theory and applications

    International Nuclear Information System (INIS)

    Rivera M, T.; Azorin N, J.

    2002-01-01

    The thermally stimulated luminescence (Tl) has occupied an important place in the Solid state physics (FES) by the flexibility of the phenomena, mainly for its applications in the fields of Radiation Physics (FR) and Medical Physics (MF). The reason of this phenomena lies in the fact of the electrons release by the action of heat. Under that same reason, it can be used the action of another stimulant agent for releasing the trapped electrons in the metastable states (EM), this agent is the light which has the same effect that the heat, giving as result the production of light photons at using light in the visible spectra, of different wavelength that the excitation light. This phenomena is called Luminescence optically stimulated (LOE). The LOE has a great impact in the Solid State Physics (FES), dating and now in the use of the phenomena as a dosimetric method, alternate to the Tl, for its use in the ionizing and non-ionizing radiations fields. (Author)

  17. Nervous control of photophores in luminescent fishes.

    Science.gov (United States)

    Zaccone, Giacomo; Abelli, Luigi; Salpietro, Lorenza; Zaccone, Daniele; Macrì, Battesimo; Marino, Fabio

    2011-07-01

    Functional studies of the autonomic innervation in the photophores of luminescent fishes are scarce. The majority of studies have involved either the stimulation of isolated photophores or the modulatory effects of adrenaline-induced light emission. The fish skin is a highly complex organ that performs a wide variety of physiological processes and receives extensive nervous innervations. The latter includes autonomic nerve fibers of spinal sympathetic origin having a secretomotor function. More recent evidence indicates that neuropeptide-containing nerve fibers, such as those that express tachykinin and its NK1 receptor, neuropeptide Y, or nitric oxide, may also play an important role in the nervous control of photophores. There is no anatomical evidence that shows that nNOS positive (nitrergic) neurons form a population distinct from the secretomotor neurons with perikarya in the sympathetic ganglia. The distribution and function of the nitrergic nerves in the luminous cells, however, is less clear. It is likely that the chemical properties of the sympathetic postganglionic neurons in the ganglia of luminescent fishes are target-specific, such as observed in mammals. Copyright © 2010 Elsevier GmbH. All rights reserved.

  18. Field detection of CO and CH4 by NIR 2f modulation laser spectroscopy

    Directory of Open Access Journals (Sweden)

    A Khorsandi

    2011-12-01

    Full Text Available   A novel compact fiber-coupled NIR system based on a DFB diode laser source is employed as a portable and sensitive gas sensor for trace detection of combustion pollutant molecules. We demonstrate the performance of such an NIR gas sensor by tracing the absorption lines of CO and CH4 using 2f-WMS technique at moderate temperature of T ~ 600°C in the recuperator channel of an industrial furnace provided by Mobarakeh steel company. This measurement shows the excellent sensitivity of the applied NIR gas sensor to the on-line and in-situ monitoring of such molecular species.

  19. Fluorescence enhancing under UV-NIR simultaneous-excitation in ZnS:Cu,Mn phosphors

    Directory of Open Access Journals (Sweden)

    L. J. Xie

    2012-12-01

    Full Text Available The fluorescence properties of a long-lasting phosphor, ZnS:Cu,Mn was studied for the first time under simultaneously excitation of both UV and NIR light. Up to 20% fluorescence enhancement of the phosphor was observed. In the present simultaneously-excitation process, broad-band NIR light was absorbed and converted to visible photons via a single-photon upconversion path. We propose that a novel kind of spectral-conversion material with the unique ability to simultaneously convert both UV and NIR photons can be developed and is promising in the application of enhancing the EQE of solar cells.

  20. The Development of Novel Near-Infrared (NIR Tetraarylazadipyrromethene Fluorescent Dyes

    Directory of Open Access Journals (Sweden)

    Young-Tae Chang

    2013-05-01

    Full Text Available Novel structures of an near-infrared (NIR tetraarylazadipyrromethene (aza-BODIPY series have been prepared. We designed the core structure containing two amido groups at the para-position of the aromatic rings. The amido group was incorporated to secure insensitivity to pH and to ensure a bathochromic shift to the NIR region. Forty members of aza-BODIPY compounds were synthesized by substitution of the acetyl group with commercial amines on the alpha bromide. The physicochemical properties and photostability were investigated and the fluorescence emission maxima (745~755 nm were found to be in the near infrared (NIR range of fluorescence.

  1. Pure zero-dimensional Cs4PbBr6 single crystal rhombohedral microdisks with high luminescence and stability.

    Science.gov (United States)

    Zhang, Haihua; Liao, Qing; Wu, Yishi; Chen, Jianwei; Gao, Qinggang; Fu, Hongbing

    2017-11-08

    Zero-dimensional (0D) perovskite Cs 4 PbBr 6 has been speculated to be an efficient solid-state emitter, exhibiting strong luminescense on achieving quantum confinement. Although several groups have reported strong green luminescence from Cs 4 PbBr 6 powders and nanocrystals, doubts that the origin of luminescence comes from Cs 4 PbBr 6 itself or CsPbBr 3 impurities have been a point of controversy in recent investigations. Herein, we developed a facile one-step solution self-assembly method to synthesize pure zero-dimensional rhombohedral Cs 4 PbBr 6 micro-disks (MDs) with a high PLQY of 52% ± 5% and photoluminescence full-width at half maximum (FWHM) of 16.8 nm. The obtained rhombohedral MDs were high quality single-crystalline as demonstrated by XRD and SAED patterns. We demonstrated that Cs 4 PbBr 6 MDs and CsPbBr 3 MDs were phase-separated from each other and the strong green emission comes from Cs 4 PbBr 6 . Power and temperature dependence spectra evidenced that the observed strong green luminescence of pure Cs 4 PbBr 6 MDs originated from direct exciton recombination in the isolated octahedra with a large binding energy of 303.9 meV. Significantly, isolated PbBr 6 4- octahedra separated by a Cs + ion insert in the crystal lattice is beneficial to maintaining the structural stability, depicting superior thermal and anion exchange stability. Our study provides an efficient approach to obtain high quality single-crystalline Cs 4 PbBr 6 MDs with highly efficient luminescence and stability for further optoelectronic applications.

  2. [Outlier sample discriminating methods for building calibration model in melons quality detecting using NIR spectra].

    Science.gov (United States)

    Tian, Hai-Qing; Wang, Chun-Guang; Zhang, Hai-Jun; Yu, Zhi-Hong; Li, Jian-Kang

    2012-11-01

    Outlier samples strongly influence the precision of the calibration model in soluble solids content measurement of melons using NIR Spectra. According to the possible sources of outlier samples, three methods (predicted concentration residual test; Chauvenet test; leverage and studentized residual test) were used to discriminate these outliers respectively. Nine suspicious outliers were detected from calibration set which including 85 fruit samples. Considering the 9 suspicious outlier samples maybe contain some no-outlier samples, they were reclaimed to the model one by one to see whether they influence the model and prediction precision or not. In this way, 5 samples which were helpful to the model joined in calibration set again, and a new model was developed with the correlation coefficient (r) 0. 889 and root mean square errors for calibration (RMSEC) 0.6010 Brix. For 35 unknown samples, the root mean square errors prediction (RMSEP) was 0.854 degrees Brix. The performance of this model was more better than that developed with non outlier was eliminated from calibration set (r = 0.797, RMSEC= 0.849 degrees Brix, RMSEP = 1.19 degrees Brix), and more representative and stable with all 9 samples were eliminated from calibration set (r = 0.892, RMSEC = 0.605 degrees Brix, RMSEP = 0.862 degrees).

  3. Near-infrared spectroscopy (NIRS evaluation and regional analysis of Chinese faba bean (Vicia faba L.

    Directory of Open Access Journals (Sweden)

    Jiaojiao Wang

    2014-02-01

    Full Text Available To analyze the nutritional composition of faba bean (Vicia faba L. seed, estimation models were developed for protein, starch, oil, and total polyphenol using near infrared spectroscopy (NIRS. Two hundred and forty-four samples from twelve producing regions were measured in both milled powder and intact seed forms. Partial least squares (PLS regression was applied for model development. The model based on ground seed powder was generally superior to that based on the intact seed. The optimal seed powder-based models for protein, starch, and total polyphenol had coefficients of correlation (r2 of 0.97, 0.93 and 0.89, respectively. The relationship between nutrient contents and twelve producing areas was determined by two-step cluster analysis. Three distinct groupings were obtained with region-constituent features, i.e., Group 1 of high oil, Group 2 of high protein, and Group 3 of high starch as well as total polyphenol. The clustering accuracy was 79.5%. Moreover, the nutrition contents were affected by seeding date, longitude, latitude, and altitude of plant location. Cluster analysis revealed that the differences in the seed were strongly influenced by geographical factors.

  4. Strong Electroweak Symmetry Breaking

    CERN Document Server

    Grinstein, Benjamin

    2011-01-01

    Models of spontaneous breaking of electroweak symmetry by a strong interaction do not have fine tuning/hierarchy problem. They are conceptually elegant and use the only mechanism of spontaneous breaking of a gauge symmetry that is known to occur in nature. The simplest model, minimal technicolor with extended technicolor interactions, is appealing because one can calculate by scaling up from QCD. But it is ruled out on many counts: inappropriately low quark and lepton masses (or excessive FCNC), bad electroweak data fits, light scalar and vector states, etc. However, nature may not choose the minimal model and then we are stuck: except possibly through lattice simulations, we are unable to compute and test the models. In the LHC era it therefore makes sense to abandon specific models (of strong EW breaking) and concentrate on generic features that may indicate discovery. The Technicolor Straw Man is not a model but a parametrized search strategy inspired by a remarkable generic feature of walking technicolor,...

  5. 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

  6. Plasmons in strong superconductors

    International Nuclear Information System (INIS)

    Baldo, M.; Ducoin, C.

    2011-01-01

    We present a study of the possible plasmon excitations that can occur in systems where strong superconductivity is present. In these systems the plasmon energy is comparable to or smaller than the pairing gap. As a prototype of these systems we consider the proton component of Neutron Star matter just below the crust when electron screening is not taken into account. For the realistic case we consider in detail the different aspects of the elementary excitations when the proton, electron components are considered within the Random-Phase Approximation generalized to the superfluid case, while the influence of the neutron component is considered only at qualitative level. Electron screening plays a major role in modifying the proton spectrum and spectral function. At the same time the electron plasmon is strongly modified and damped by the indirect coupling with the superfluid proton component, even at moderately low values of the gap. The excitation spectrum shows the interplay of the different components and their relevance for each excitation modes. The results are relevant for neutrino physics and thermodynamical processes in neutron stars. If electron screening is neglected, the spectral properties of the proton component show some resemblance with the physical situation in high-T c superconductors, and we briefly discuss similarities and differences in this connection. In a general prospect, the results of the study emphasize the role of Coulomb interaction in strong superconductors.

  7. 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

  8. 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.

  9. 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.

  10. Luminescence properties of calcium doped zinc oxide nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    El Mir, L., E-mail: Lassaad.ElMir@fsg.rnu.tn [Al Imam Mohammad Ibn Saud Islamic University (IMSIU), College of Sciences, Department of Physics, Riyadh 11623 (Saudi Arabia); Laboratory of Physics of Materials and Nanomaterials Applied at Environment (LaPhyMNE), Gabes University, Faculty of Sciences in Gabes, Gabes (Tunisia)

    2017-06-15

    Aerogel nanopowder of calcium-doped zinc oxide (ZnO:Ca) was synthesized by modified sol-gel method. In this process, hydrolyses was slowly released and followed by a thermal drying in supercritical conditions or ethyl alcohol. The obtained nanopowder was characterized by various techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Cathodoluminescence (CL) and photoluminescence (PL). XRD data showed that Ca-doped ZnO sample has a hexagonal wurtzite structure with a slight distortion of ZnO lattice and no extra secondary phases, suggesting the substitution of Ca ions in the ZnO structure. SEM micrograph shows spherical microparticles having a rough porous fine-grained. From TEM micrograph, the samples are composed by single particles having an inhomogeneous size distribution, with most of them having a dimension in the range between 20 and 50 nm. This powder presents a strong photoluminescence band in the visible range. From photoluminescence excitation (PLE) the energy position of the obtained PL band depends on the wavelength of excitation. The luminescence results are also confirmed by cathodoluminescence technique and suggests the presence of photo-active centers in ZnO:Ca as deduced from new published works for visible photo-activated gas sensors and photo-catalysis of dyes degradation. We hope that this work provides some answers to the scientific community concerning the effect of doping in the creation of optical active centers in ZnO, promising for many technological applications.

  11. A pH-responsive molecular switch with tricolor luminescence.

    Science.gov (United States)

    Ahn, Hyungmin; Hong, Jaewan; Kim, Sung Yeon; Choi, Ilyoung; Park, Moon Jeong

    2015-01-14

    We developed a new ratiometric pH sensor based on poly(N-phenylmaleimide) (PPMI)-containing block copolymer that emits three different fluorescent colors depending on the pH. The strong solvatochromism and tautomerism of the PPMI derivatives enabled precise pH sensing for almost the entire range of the pH scale. Theoretical calculations have predicted largely dissimilar band gaps for the keto, enol, and enolate tautomers of PPMI owing to low-dimensional conjugation effects. The tunable emission wavelength and intensity of our sensors, as well as the reversible color switching with high-luminescent contrast, were achieved using rational molecular design of PPMI analogues as an innovative platform for accurate H(+) detection. The self-assembly of block copolymers on the nanometer length scale was particularly highlighted as a novel prospective means of regulating fluorescence properties while avoiding the self-quenching phenomenon, and this system can be used as a fast responsive pH sensor in versatile device forms.

  12. Mitochondrial respiratory complex I probed by delayed luminescence spectroscopy

    Science.gov (United States)

    Baran, Irina; Ionescu, Diana; Privitera, Simona; Scordino, Agata; Mocanu, Maria Magdalena; Musumeci, Francesco; Grasso, Rosaria; Gulino, Marisa; Iftime, Adrian; Tofolean, Ioana Teodora; Garaiman, Alexandru; Goicea, Alexandru; Irimia, Ruxandra; Dimancea, Alexandru; Ganea, Constanta

    2013-12-01

    The role of mitochondrial complex I in ultraweak photon-induced delayed photon emission [delayed luminescence (DL)] of human leukemia Jurkat T cells was probed by using complex I targeting agents like rotenone, menadione, and quercetin. Rotenone, a complex I-specific inhibitor, dose-dependently increased the mitochondrial level of reduced nicotinamide adenine dinucleotide (NADH), decreased clonogenic survival, and induced apoptosis. A strong correlation was found between the mitochondrial levels of NADH and oxidized flavin mononucleotide (FMNox) in rotenone-, menadione- and quercetin-treated cells. Rotenone enhanced DL dose-dependently, whereas quercetin and menadione inhibited DL as well as NADH or FMNox. Collectively, the data suggest that DL of Jurkat cells originates mainly from mitochondrial complex I, which functions predominantly as a dimer and less frequently as a tetramer. In individual monomers, both pairs of pyridine nucleotide (NADH/reduced nicotinamide adenine dinucleotide phosphate) sites and flavin (FMN-a/FMN-b) sites appear to bind cooperatively their specific ligands. Enhancement of delayed red-light emission by rotenone suggests that the mean time for one-electron reduction of ubiquinone or FMN-a by the terminal Fe/S center (N2) is 20 or 284 μs, respectively. All these findings suggest that DL spectroscopy could be used as a reliable, sensitive, and robust technique to probe electron flow within complex I in situ.

  13. Optical and Thermal Stability of Oligofluorene/Rubber Luminescent Blend.

    Science.gov (United States)

    Barbosa, Camila G; Faez, Roselena; Péres, Laura O

    2016-09-01

    This paper proposes to obtain homogeneous and stable blends of oligo(9,9-dioctylfluorene)-co-phenylene (OF), a conjugated oligomer with strong tendency of formation of excimers in the solid state, and nitrile rubber (NBR). This rubber protection reduces the formation of polymer excimers in the films. The fluorene oligomer was synthesized via Suzuki reaction and incorporated in the nitrile rubber. The films were formed by spin coating and casting techniques on the proportions of 1, 5, 10, 20 and 50 % (w/w) of OF in the nitrile rubber (NBR). The structural, optical and thermal properties of the films were evaluated with infrared, UV-Vis, fluorescence and thermogravimetry, respectively. The nitrile rubber proved to be essential for the preparation of homogeneous and stable films, since it was not possible to obtain films with only fluorene using the above-mentioned techniques. Furthermore, luminescent properties of OF are unchanged and the excimers formation in the solid state decrease suggesting the efficiency of nitrile rubber as the matrix for making films.

  14. Preparation of carbon quantum dots based high photostability luminescent membranes.

    Science.gov (United States)

    Zhao, Jinxing; Liu, Cui; Li, Yunchuan; Liang, Jiyuan; Liu, Jiyan; Qian, Tonghui; Ding, Jianjun; Cao, Yuan-Cheng

    2017-06-01

    Urethane acrylate (UA) was used to prepare carbon quantum dots (C-dots) luminescent membranes and the resultants were examined with FT-IR, mechanical strength, scanning electron microscope (SEM) and quantum yields (QYs). FT-IR results showed the polyurethane acrylate (PUA) prepolymer -C = C-vibration at 1101 cm -1 disappeared but there was strong vibration at1687cm -1 which was contributed from the-C = O groups in cross-linking PUA. Mechanical strength results showed that the different quantity of C-dots loadings and UV-curing time affect the strength. SEM observations on the cross-sections of the membranes are uniform and have no structural defects, which prove that the C-dots are compatible with the water-soluble PUA resin. The C-dot loading was increased from 0 to 1 g, the maximum tensile stress was nearly 2.67 MPa, but the tensile strain was decreased from 23.4% to 15.1% and 7.2% respectively. QYs results showed that the C-dots in the membrane were stable after 120 h continuous irradiation. Therefore, the C-dots photoluminescent film is the promising material for the flexible devices in the future applications. Copyright © 2016 John Wiley & Sons, Ltd.

  15. Desiccants for retrospective dosimetry using optically stimulated luminescence (OSL)

    International Nuclear Information System (INIS)

    Geber-Bergstrand, Therése; Bernhardsson, Christian; Christiansson, Maria; Mattsson, Sören; Rääf, Christopher L.

    2015-01-01

    Optically stimulated luminescence (OSL) was used to test different kinds of desiccants for their potential use in retrospective dosimetry. Desiccants are used for the purpose of absorbing liquids and can be found in a number of items which may be found in the immediate environment of a person, including hand bags, drug packages, and the vehicles of rescue service teams. Any material exhibiting OSL properties suitable for retrospective dosimetry is a useful addition to the existing dosimetry system available in emergency preparedness. Eleven kinds of desiccants were investigated in order to obtain an overview of the fundamental OSL properties necessary for retrospective dosimetry. Measurements were made using a Risø TL/OSL reader and irradiations were achieved with the 90 Sr/ 90 Y source incorporated in the reader. Several of the desiccants exhibited promising properties as retrospective dosemeters. Some of the materials exhibited a strong as-received signal, i.e. without any laboratory irradiation, but the origin of this signal has not yet been established. The minimum detectable dose ranged from 8 to 450 mGy for ten of the materials and for one material (consisting of natural clay) the minimum detectable dose was 1.8 Gy. - Highlights: • Desiccants can be used as fortuitous dosemeters using OSL. • The minimum detectable dose for processed desiccants range from 8 to 450 mGy. • The minimum detectable dose for natural clay was 1.8 Gy

  16. Optical and luminescence properties of hydrogenated amorphous carbon

    International Nuclear Information System (INIS)

    Rusli

    1996-03-01

    In this thesis, the optical and luminescence properties of hydrogenated amorphous carbon(a - C:H) thin films deposited using a Plasma Enhanced Chemical Vapour Deposition (PECVD) system are studied. A photoluminescence (PL) measuring system with a wavelength range of 300nm to 900nm, used for the above study, has been set up as a main part of the research. Firstly, a simple yet powerful method developed to solve for the optical constants and thickness of a - C : H deposited on Si is presented. This is followed by an investigation into the optical properties of band gap modulated a - C : H thin films superlattice structures. a - C : H films, obtained from a wide range of deposition conditions, are then characterised in terms of their optical absorption, infrared absorption, Raman scattering, fraction of sp 2 to sp 3 bondings and unpaired electron spin density. Their PL characteristics, such as the peak emission energy, spectral bandwidth, quantum efficiency, fatigue and polarisation memory are investigated in relation to their microstructure. The results, taken together with those obtained from photoconductivity study and electric field quenching of PL, are used to understand the origin of the strong PL in a - C : H. Preliminary work on a - C : H electroluminescent celbis also presented. (author)

  17. Luminescence and Luminescence Quenching of K2Bi(PO4)(MoO4):Eu3+ Phosphors with Efficiencies Close to Unity.

    Science.gov (United States)

    Grigorjevaite, Julija; Katelnikovas, Arturas

    2016-11-23

    A very good light emitting diode (LED) phosphor must have strong absorption, high quantum efficiency, high color purity, and high quenching temperature. Our synthesized K 2 Bi(PO 4 )(MoO 4 ):Eu 3+ phosphors possess all of the mentioned properties. The excitation of these phosphors with the near-UV or blue radiation results in a bright red luminescence dominated by the 5 D 0 → 7 F 2 transition at ∼615 nm. Color coordinates are very stable when changing Eu 3+ concentration or temperature in the range of 77-500 K. Furthermore, samples doped with 50% and 75% Eu 3+ showed quantum efficiencies close to 100% which is a huge benefit for practical application. Temperature dependent luminescence measurements showed that phosphor performance increases with increasing Eu 3+ concentration. K 2 Eu(PO 4 )(MoO 4 ) sample at 400 K lost only 20% of the initial intensity at 77 K and would lose half of the intensity only at 578 K. Besides, the ceramic disks with thicknesses of 0.33 and 0.89 mm were prepared from K 2 Eu(PO 4 )(MoO 4 ) powder, and it turned out that they efficiently converted the radiation of 375 nm LED to the red light. The conversion of 400 nm LED radiation to the red light was not complete; thus, the light sources with various tints of purple color were obtained. The combination of ceramic disks with 455 nm LED yielded the light sources with tints of blue color due to the low absorption of ceramic disk in this spectral range. In addition, these phosphors possess a very unique emission spectra; thus, they could also be applied in luminescent security pigments.

  18. 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

  19. 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

  20. 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)

  1. 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...

  2. 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

  3. 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...

  4. Container Verification Using Optically Stimulated Luminescence

    International Nuclear Information System (INIS)

    Tanner, Jennifer E.; Miller, Steven D.; Conrady, Matthew M.; Simmons, Kevin L.; Tinker, Michael R.

    2008-01-01

    Containment verification is a high priority for safeguards containment and surveillance. Nuclear material containers, safeguards equipment cabinets, camera housings, and detector cable conduit are all vulnerable to tampering. Even with a high security seal on a lid or door, custom-built hinges and interfaces, and special colors and types of finishes, the surfaces of enclosures can be tampered with and any penetrations repaired and covered over. With today's technology, these repairs would not be detected during a simple visual inspection. Several suggested solutions have been to develop complicated networks of wires, fiber-optic cables, lasers or other sensors that line the inside of a container and alarm when the network is disturbed. This results in an active system with real time evidence of tampering but is probably not practical for most safeguards applications. A more practical solution would be to use a passive approach where an additional security feature was added to surfaces which would consist of a special coating or paint applied to the container or enclosure. One type of coating would incorporate optically stimulated luminescent (OSL) material. OSL materials are phosphors that luminesce in proportion to the ionizing radiation dose when stimulated with the appropriate optical wavelengths. The OSL fluoresces at a very specific wavelength when illuminated at another, very specific wavelength. The presence of the pre-irradiated OSL material in the coating is confirmed using a device that interrogates the surface of the enclosure using the appropriate optical wavelength and then reads the resulting luminescence. The presence of the OSL indicates that the integrity of the surface is intact. The coating itself could be transparent which would allow the appearance of the container to remain unchanged or the OSL material could be incorporated into certain paints or epoxies used on various types of containers. The coating could be applied during manufacturing

  5. Detection of food irradiation with luminescence methods

    International Nuclear Information System (INIS)

    Anderle, H.

    1997-06-01

    Food irradiation is applied as method for the preservation of foods, the prevention of food spoilage and the inhibition of food-borne pathogens. Doses exceeding 10 kGy (10 kJ/kg) are not recommended by the WHO. The different legislation requires methods for the detection and the closimetry of irradiated foods. Among the physical methods based on the radiation-induced changes in inorganic, nonhygroscopic crystalline solids are thermoluminescence (TL), photostimulated luminescence (PSL) and lyoluminescence (LL) measurement. The luminescence methods were tested on natural minerals. Pure quartz, feldspars, calcite, aragonite and dolomite of known origin were irradiated, read out and analyzed to determine the influence of luminescence-activators and deactivators. Carbonate minerals show an orange-red TL easily detectable by blue-sensitive photomultiplier tubes. TIL-inactive carbonate samples may be identified by a lyoluminescence method using the reaction of trapped irradiation-generated charge carriers with the solvent during crystal-lattice breakup. The fine-ground mineral is dissolved in an alkaline complexing agent/chemiluminescence sensitizer/chemiluminescence catalyst (EDTA/luminol/hemin) reagent mixture. The TL and PSL of quartz is too weak to contribute a significant part for the corresponding signals in polymineral dust. Alkali and soda feldspar show intense TL and PSL. The temperature maxima in the TL glow curves allow a clear distinction. PSL does not give this additional information, it suffers from bleaching by ambient light and requires light-protection. Grain disinfestated with low irradiation doses (500 Gy) may not identified by both TL and PSL measurement. The natural TL of feldspar particles may be overlap with the irradiation-induced TL of other minerals. As a routine method, irradiated spices are identified with TL measurement. The dust particles have to be enriched by heavy-liquid flotation and centrifugation. The PSL method allows a clear

  6. Epitaxial growth of hetero-Ln-MOF hierarchical single crystals for domain- and orientation-controlled multicolor luminescence 3D coding capability

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Mei; Zhu, Yi-Xuan; Wu, Kai; Chen, Ling; Hou, Ya-Jun; Yin, Shao-Yun; Wang, Hai-Ping; Fan, Ya-Nan [MOE Laboratory of Bioinorganic and Synthetic Chemistry, Lehn Institute of Functional Materials, School of Chemistry, Sun Yat-Sen University, Guangzhou (China); Su, Cheng-Yong [MOE Laboratory of Bioinorganic and Synthetic Chemistry, Lehn Institute of Functional Materials, School of Chemistry, Sun Yat-Sen University, Guangzhou (China); State Key Laboratory of Applied Organic Chemistry, Lanzhou University, Lanzhou (China)

    2017-11-13

    Core-shell or striped heteroatomic lanthanide metal-organic framework hierarchical single crystals were obtained by liquid-phase anisotropic epitaxial growth, maintaining identical periodic organization while simultaneously exhibiting spatially segregated structure. Different types of domain and orientation-controlled multicolor photophysical models are presented, which show either visually distinguishable or visible/near infrared (NIR) emissive colors. This provides a new bottom-up strategy toward the design of hierarchical molecular systems, offering high-throughput and multiplexed luminescence color tunability and readability. The unique capability of combining spectroscopic coding with 3D (three-dimensional) microscale spatial coding is established, providing potential applications in anti-counterfeiting, color barcoding, and other types of integrated and miniaturized optoelectronic materials and devices. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  7. Epitaxial Growth of Hetero-Ln-MOF Hierarchical Single Crystals for Domain- and Orientation-Controlled Multicolor Luminescence 3D Coding Capability.

    Science.gov (United States)

    Pan, Mei; Zhu, Yi-Xuan; Wu, Kai; Chen, Ling; Hou, Ya-Jun; Yin, Shao-Yun; Wang, Hai-Ping; Fan, Ya-Nan; Su, Cheng-Yong

    2017-11-13

    Core-shell or striped heteroatomic lanthanide metal-organic framework hierarchical single crystals were obtained by liquid-phase anisotropic epitaxial growth, maintaining identical periodic organization while simultaneously exhibiting spatially segregated structure. Different types of domain and orientation-controlled multicolor photophysical models are presented, which show either visually distinguishable or visible/near infrared (NIR) emissive colors. This provides a new bottom-up strategy toward the design of hierarchical molecular systems, offering high-throughput and multiplexed luminescence color tunability and readability. The unique capability of combining spectroscopic coding with 3D (three-dimensional) microscale spatial coding is established, providing potential applications in anti-counterfeiting, color barcoding, and other types of integrated and miniaturized optoelectronic materials and devices. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Epitaxial growth of hetero-Ln-MOF hierarchical single crystals for domain- and orientation-controlled multicolor luminescence 3D coding capability

    International Nuclear Information System (INIS)

    Pan, Mei; Zhu, Yi-Xuan; Wu, Kai; Chen, Ling; Hou, Ya-Jun; Yin, Shao-Yun; Wang, Hai-Ping; Fan, Ya-Nan; Su, Cheng-Yong

    2017-01-01

    Core-shell or striped heteroatomic lanthanide metal-organic framework hierarchical single crystals were obtained by liquid-phase anisotropic epitaxial growth, maintaining identical periodic organization while simultaneously exhibiting spatially segregated structure. Different types of domain and orientation-controlled multicolor photophysical models are presented, which show either visually distinguishable or visible/near infrared (NIR) emissive colors. This provides a new bottom-up strategy toward the design of hierarchical molecular systems, offering high-throughput and multiplexed luminescence color tunability and readability. The unique capability of combining spectroscopic coding with 3D (three-dimensional) microscale spatial coding is established, providing potential applications in anti-counterfeiting, color barcoding, and other types of integrated and miniaturized optoelectronic materials and devices. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  9. Comparing the analytical performances of Micro-NIR and FT-NIR spectrometers in the evaluation of acerola fruit quality, using PLS and SVM regression algorithms.

    Science.gov (United States)

    Malegori, Cristina; Nascimento Marques, Emanuel José; de Freitas, Sergio Tonetto; Pimentel, Maria Fernanda; Pasquini, Celio; Casiraghi, Ernestina

    2017-04-01

    The main goal of this study was to investigate the analytical performances of a state-of-the-art device, one of the smallest dispersion NIR spectrometers on the market (MicroNIR 1700), making a critical comparison with a benchtop FT-NIR spectrometer in the evaluation of the prediction accuracy. In particular, the aim of this study was to estimate in a non-destructive manner, titratable acidity and ascorbic acid content in acerola fruit during ripening, in a view of direct applicability in field of this new miniaturised handheld device. Acerola (Malpighia emarginata DC.) is a super-fruit characterised by a considerable amount of ascorbic acid, ranging from 1.0% to 4.5%. However, during ripening, acerola colour changes and the fruit may lose as much as half of its ascorbic acid content. Because the variability of chemical parameters followed a non-strictly linear profile, two different regression algorithms were compared: PLS and SVM. Regression models obtained with Micro-NIR spectra give better results using SVM algorithm, for both ascorbic acid and titratable acidity estimation. FT-NIR data give comparable results using both SVM and PLS algorithms, with lower errors for SVM regression. The prediction ability of the two instruments was statistically compared using the Passing-Bablok regression algorithm; the outcomes are critically discussed together with the regression models, showing the suitability of the portable Micro-NIR for in field monitoring of chemical parameters of interest in acerola fruits. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. Strongly intensive quantities

    International Nuclear Information System (INIS)

    Gorenstein, M. I.; Gazdzicki, M.

    2011-01-01

    Analysis of fluctuations of hadron production properties in collisions of relativistic particles profits from use of measurable intensive quantities which are independent of system size variations. The first family of such quantities was proposed in 1992; another is introduced in this paper. Furthermore we present a proof of independence of volume fluctuations for quantities from both families within the framework of the grand canonical ensemble. These quantities are referred to as strongly intensive ones. Influence of conservation laws and resonance decays is also discussed.

  11. Strong-coupling approximations

    International Nuclear Information System (INIS)

    Abbott, R.B.

    1984-03-01

    Standard path-integral techniques such as instanton calculations give good answers for weak-coupling problems, but become unreliable for strong-coupling. Here we consider a method of replacing the original potential by a suitably chosen harmonic oscillator potential. Physically this is motivated by the fact that potential barriers below the level of the ground-state energy of a quantum-mechanical system have little effect. Numerically, results are good, both for quantum-mechanical problems and for massive phi 4 field theory in 1 + 1 dimensions. 9 references, 6 figures

  12. Quantitative interpretations of Visible-NIR reflectance spectra of blood.

    Science.gov (United States)

    Serebrennikova, Yulia M; Smith, Jennifer M; Huffman, Debra E; Leparc, German F; García-Rubio, Luis H

    2008-10-27

    This paper illustrates the implementation of a new theoretical model for rapid quantitative analysis of the Vis-NIR diffuse reflectance spectra of blood cultures. This new model is based on the photon diffusion theory and Mie scattering theory that have been formulated to account for multiple scattering populations and absorptive components. This study stresses the significance of the thorough solution of the scattering and absorption problem in order to accurately resolve for optically relevant parameters of blood culture components. With advantages of being calibration-free and computationally fast, the new model has two basic requirements. First, wavelength-dependent refractive indices of the basic chemical constituents of blood culture components are needed. Second, multi-wavelength measurements or at least the measurements of characteristic wavelengths equal to the degrees of freedom, i.e. number of optically relevant parameters, of blood culture system are required. The blood culture analysis model was tested with a large number of diffuse reflectance spectra of blood culture samples characterized by an extensive range of the relevant parameters.

  13. Learning word order at birth: A NIRS study

    Directory of Open Access Journals (Sweden)

    Silvia Benavides-Varela

    2017-06-01

    Full Text Available In language, the relative order of words in sentences carries important grammatical functions. However, the developmental origins and the neural correlates of the ability to track word order are to date poorly understood. The current study therefore investigates the origins of infants’ ability to learn about the sequential order of words, using near-infrared spectroscopy (NIRS with newborn infants. We have conducted two experiments: one in which a word order change was implemented in 4-word sequences recorded with a list intonation (as if each word was a separate item in a list; list prosody condition, Experiment 1 and one in which the same 4-word sequences were recorded with a well-formed utterance-level prosodic contour (utterance prosody condition, Experiment 2. We found that newborns could detect the violation of the word order in the list prosody condition, but not in the utterance prosody condition. These results suggest that while newborns are already sensitive to word order in linguistic sequences, prosody appears to be a stronger cue than word order for the identification of linguistic units at birth.

  14. 2003-2004 ACADEMIC TRAINING PROGRAMME: Y. NIR

    CERN Multimedia

    Françoise Benz

    2004-01-01

    ACADEMIC TRAINING Françoise Benz tel. 73127 academic.training@cern.ch 22, 23, 24, 25 and 26 March LECTURE SERIES From 11:00 to 12:00 hrs Main Auditorium bldg. 500 on 22, 24, 25 and 26 March TH Auditorium bldg 4 on 23 March Neutrinos Y. NIR, Weizmann Institute of Science, Rehovot, Israel The Standard Model predicts that the neutrinos are massless and do not mix. Generic extensions of the Standard Model predict that neutrinos are massive (but, very likely, much lighter than the charged fermions). Therefore, the search for neutrino masses and mixing tests the Standard Model and probes new physics. Measurements of various features of the fluxes of atmospheric, solar and, more recently, reactor neutrinos have provided evidence for neutrino oscillations and therefore for neutrino masses and mixing. These results have significant theoretical implications: new physics exists, and its scale can be estimated. There are interesting lessons for grand unified theories and for models of extra dimensions. T...

  15. NIRS report concerning the cyclotron usages. FY 2000

    International Nuclear Information System (INIS)

    2001-07-01

    This report describes the National Institute of Radiological Sciences (NIRS) cyclotron usages concerning of: Operation and improvement-development of the cyclotrons in 2000 (total 1,302 hr operation, development of the insulating septum, renewal of the magnetic channel and radiofrequency (RF) pre-amplifier, and improvement of the magnetic interference); Development of neutron detectors in the cosmic environment (the phoswich detector, low-pressure proportional counter, bubble dosimeter and new type phoswich detector); Development of detectors of charged particle components in the cosmic radiation (Liulin-4J and position sensitive silicon detector); Measurement of the energy and angular distribution of secondary electrons from water vapor with heavy-ion impact; Phase II clinical trials of proton beam therapy for ophthalmological tumors (34 patients in 1996-2000 and survival rate 100% within 3 years); Application of cyclotrons for RI production (mainly, 11 C, 13 N, 15 O and 18 F for basic and clinical PET); Studies on the spread-out peak of proton beam (for radiotherapy); and Related materials to above (details). (N.I.)

  16. Learning word order at birth: A NIRS study.

    Science.gov (United States)

    Benavides-Varela, Silvia; Gervain, Judit

    2017-06-01

    In language, the relative order of words in sentences carries important grammatical functions. However, the developmental origins and the neural correlates of the ability to track word order are to date poorly understood. The current study therefore investigates the origins of infants' ability to learn about the sequential order of words, using near-infrared spectroscopy (NIRS) with newborn infants. We have conducted two experiments: one in which a word order change was implemented in 4-word sequences recorded with a list intonation (as if each word was a separate item in a list; list prosody condition, Experiment 1) and one in which the same 4-word sequences were recorded with a well-formed utterance-level prosodic contour (utterance prosody condition, Experiment 2). We found that newborns could detect the violation of the word order in the list prosody condition, but not in the utterance prosody condition. These results suggest that while newborns are already sensitive to word order in linguistic sequences, prosody appears to be a stronger cue than word order for the identification of linguistic units at birth. Copyright © 2017. Published by Elsevier Ltd.

  17. New NIR Absorbing DPP-based Polymer for Thick Organic Solar Cells

    KAUST Repository

    Oklem, Gulce; Song, Xin; Toppare, Levent; Baran, Derya; Gunbas, Gorkem

    2018-01-01

    infrared region (NIR) for better photon harvesting in organic solar cells. It has been shown that copolymers compromising diketopyrrolopyrrole based acceptors and simple donors (thiophene or furan) achieve absorption maximum around 800 nm

  18. Optofluidic interferometry chip designs of differential NIR absorbance based sensors for identification and quantification of electrolytes

    NARCIS (Netherlands)

    Steen, Gerrit W.; Wexler, Adam D.; Offerhaus, Herman L.

    2014-01-01

    Design and optimization of integrated photonic NIR absorbance based sensors for identification and quantification of aqueous electrolytes was performed by simulation in MATLAB and Optodesigner. Ten designs are presented and compared for suitability.

  19. Near-infrared spectroscopy (NIRS) as a new tool for neuroeconomic research

    Science.gov (United States)

    Kopton, Isabella M.; Kenning, Peter

    2014-01-01

    Over the last decade, the application of neuroscience to economic research has gained in importance and the number of neuroeconomic studies has grown extensively. The most common method for these investigations is fMRI. However, fMRI has limitations (particularly concerning situational factors) that should be countered with other methods. This review elaborates on the use of functional Near-Infrared Spectroscopy (fNIRS) as a new and promising tool for investigating economic decision making both in field experiments and outside the laboratory. We describe results of studies investigating the reliability of prototype NIRS studies, as well as detailing experiments using conventional and stationary fNIRS devices to analyze this potential. This review article shows that further research using mobile fNIRS for studies on economic decision making outside the laboratory could be a fruitful avenue helping to develop the potential of a new method for field experiments outside the laboratory. PMID:25147517

  20. Near Infrared Spectroscopy (NIRS) for the determination of the milk fat fatty acid profile of goats.

    Science.gov (United States)

    Núñez-Sánchez, N; Martínez-Marín, A L; Polvillo, O; Fernández-Cabanás, V M; Carrizosa, J; Urrutia, B; Serradilla, J M

    2016-01-01

    Milk fatty acid (FA) composition is important for the goat dairy industry because of its influence on cheese properties and human health. The aim of the present work was to evaluate the feasibility of NIRS reflectance (oven-dried milk using the DESIR method) and transflectance (liquid milk) analysis to predict milk FA profile and groups of fats in milk samples from individual goats. NIRS analysis of milk samples allowed to estimate FA contents and their ratios and indexes in fat with high precision and accuracy. In general, transflectance analysis gave better or similar results than reflectance mode. Interestingly, NIRS analysis allowed direct prediction of the Atherogenicity and Thrombogenicity indexes, which are useful for the interpretation of the nutritional value of goat milk. Therefore, the calibrations obtained in the present work confirm the viability of NIRS as a fast, reliable and effective analytical method to provide nutritional information of milk samples. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. Rapid analysis of hay attributes using NIRS. Final report, Task II alfalfa supply system

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-10-24

    This final report provides technical information on the development of a near infrared reflectance spectroscopy (NIRS) system for the analysis of alfalfa hay. The purpose of the system is to provide consistent quality for processing alfalfa stems for fuel and alfalfa leaf meal products for livestock feed. Project tasks were to: (1) develop an NIRS driven analytical system for analysis of alfalfa hay and processed alfalfa products; (2) assist in hiring a qualified NIRS technician and recommend changes in testing equipment necessary to provide accurate analysis; (3) calibrate the NIRS instrument for accurate analyses; and (4) develop prototype equipment and sampling procedures as a first step towards development of a totally automated sampling system that would rapidly sample and record incoming feedstock and outbound product. An accurate hay testing program was developed, along with calibration equations for analyzing alfalfa hay and sun-cured alfalfa pellets. A preliminary leaf steam calibration protocol was also developed. 7 refs., 11 figs., 10 tabs.

  2. Interference Tolerant Functional Near Infrared Spectrometer (fNIRS) for Cognitive State Monitoring

    Data.gov (United States)

    National Aeronautics and Space Administration — Measuring hemoglobin concentration changes in the brain with Functional Near Infrared Spectroscopy (fNIRS) is a promising technique for monitoring cognitive state...

  3. Acrylamide inverse miniemulsion polymerization: in situ, real-time monitoring using nir spectroscopy

    Directory of Open Access Journals (Sweden)

    M. M. E. Colmán

    2014-12-01

    Full Text Available In this work, the ability of on-line NIR spectroscopy for the prediction of the evolution of monomer concentration, conversion and average particle diameter in acrylamide inverse miniemulsion polymerization was evaluated. The spectral ranges were chosen as those representing the decrease in concentration of monomer. An increase in the baseline shift indicated that the NIR spectra were affected by particle size. Multivariate partial least squares calibration models were developed to relate NIR spectra collected by the immersion probe with off-line conversion and polymer particle size data. The results showed good agreement between off-line data and values predicted by the NIR calibration models and these latter were also able to detect different types of operational disturbances. These results indicate that it is possible to monitor variables of interest during acrylamide inverse miniemulsion polymerizations.

  4. Monitoring tissue oxygen availability with near infrared spectroscopy (NIRS) in health and disease

    DEFF Research Database (Denmark)

    Boushel, Robert Christopher; Langberg, H; Olesen, J

    2001-01-01

    , brain and connective tissue, and more recently it has been used in the clinical setting to assess circulatory and metabolic abnormalities. Quantitative measures of blood flow are also possible using NIRS and a light-absorbing tracer, which can be applied to evaluate circulatory responses to exercise......Near infrared spectroscopy (NIRS) is becoming a widely used research instrument to measure tissue oxygen (O2) status non-invasively. Continuous-wave spectrometers are the most commonly used devices, which provide semi-quantitative changes in oxygenated and deoxygenated hemoglobin in small blood...... vessels (arterioles, capillaries and venules). Refinement of NIRS hardware and the algorithms used to deconvolute the light absorption signal have improved the resolution and validity of cytochrome oxidase measurements. NIRS has been applied to measure oxygenation in a variety of tissues including muscle...

  5. PAT: From Western solid dosage forms to Chinese materia medica preparations using NIR-CI.

    Science.gov (United States)

    Zhou, Luwei; Xu, Manfei; Wu, Zhisheng; Shi, Xinyuan; Qiao, Yanjiang

    2016-01-01

    Near-infrared chemical imaging (NIR-CI) is an emerging technology that combines traditional near-infrared spectroscopy with chemical imaging. Therefore, NIR-CI can extract spectral information from pharmaceutical products and simultaneously visualize the spatial distribution of chemical components. The rapid and non-destructive features of NIR-CI make it an attractive process analytical technology (PAT) for identifying and monitoring critical control parameters during the pharmaceutical manufacturing process. This review mainly focuses on the pharmaceutical applications of NIR-CI in each unit operation during the manufacturing processes, from the Western solid dosage forms to the Chinese materia medica preparations. Finally, future applications of chemical imaging in the pharmaceutical industry are discussed. Copyright © 2015 John Wiley & Sons, Ltd.

  6. [Real-time detection of quality of Chinese materia medica: strategy of NIR model evaluation].

    Science.gov (United States)

    Wu, Zhi-sheng; Shi, Xin-yuan; Xu, Bing; Dai, Xing-xing; Qiao, Yan-jiang

    2015-07-01

    The definition of critical quality attributes of Chinese materia medica ( CMM) was put forward based on the top-level design concept. Nowadays, coupled with the development of rapid analytical science, rapid assessment of critical quality attributes of CMM was firstly carried out, which was the secondary discipline branch of CMM. Taking near infrared (NIR) spectroscopy as an example, which is a rapid analytical technology in pharmaceutical process over the past decade, systematic review is the chemometric parameters in NIR model evaluation. According to the characteristics of complexity of CMM and trace components analysis, a multi-source information fusion strategy of NIR model was developed for assessment of critical quality attributes of CMM. The strategy has provided guideline for NIR reliable analysis in critical quality attributes of CMM.

  7. Novel self-assembled sandwich nanomedicine for NIR-responsive release of NO

    Science.gov (United States)

    Fan, Jing; He, Qianjun; Liu, Yi; Ma, Ying; Fu, Xiao; Liu, Yijing; Huang, Peng; He, Nongyue; Chen, Xiaoyuan

    2015-01-01

    A novel sandwich nanomedicine (GO-BNN6) for near-infrared (NIR) light responsive release of nitric oxide (NO) has been constructed by self-assembling of graphene oxide (GO) nanosheets and a NO donor BNN6 through the π-π stacking interaction. GO-BNN6 nanomedicine has an extraordinarily high drug loading capacity (1.2 mg BNN6 per mg GO), good thermal stability, and high NIR responsiveness. The NO release from GO-BNN6 can be easily triggered and effectively controlled by adjusting the switching, irradiation time and power density of NIR laser. The intracellular NIR-responsive release of NO from GO-BNN6 nanomedicine causes a remarkable anti-cancer effect. PMID:26568270

  8. Anterior temporal artery tap to identify systemic interference using short-separation NIRS measurements

    DEFF Research Database (Denmark)

    Sood, Mehak; Jindal, Utkarsh; Chowdhury, Shubhajit Roy

    2015-01-01

    that are also affected by tDCS. An approach may be to use short optode separations to measure systemic hemodynamic fluctuations occurring in the superficial layers which can then be used as regressors to remove the systemic contamination. Here, we demonstrate that temporal artery tap may be used to better...... of neural activity is possible with a measure of cerebral hemoglobin oxygenation using near-infrared spectroscopy (NIRS). In principal accordance, NIRS can capture the hemodynamic response to tDCS but the challenge remains in removing the systemic interference occurring in the superficial layers of the head...... identify systemic interference using this short-separation NIRS. Moreover, NIRS-EEG joint-imaging during anodal tDCS was used to measure changes in mean cerebral haemoglobin oxygen saturation (rSO2) along with changes in the log-transformed mean-power of EEG within 0.5 Hz-11.25 Hz. We found that percent...

  9. Optical spectroscopy and luminescence properties of Ho3+ doped zinc fluorophosphate (ZFP) glasses for green luminescent device applications

    Science.gov (United States)

    Reddy Prasad, V.; Damodaraiah, S.; Ratnakaram, Y. C.

    2018-04-01

    Ho3+ doped zinc fluorophosphate (ZFP) glasses with molar chemical compositions, (60-x) NH4H2PO4+20ZnO+10BaF2+10NaF+xHo2O3 (where x = 0.1, 0.3, 0.5, 1.0 and 1.5 mol%) were prepared by melt quenching technique. These glasses were characterized through physical, structural, optical, excitation, luminescence and decay curve analysis. From the absorption spectra, spectral intensities (fexp and fcal), Judd-Ofelt intensity parameters (Ω2, Ω4 and Ω6), radiative transition probabilities (AT), radiative lifetimes (τR) and branching ratios (βR) were evaluated for all Ho3+ doped ZFP glass matrices. From the photoluminescence spectra, peak stimulated emission cross-sections (σP) were calculated for all Ho3+ doped ZFP glasses. The Ho3+ doped ZFP glasses show strong green emission at 545 nm and red emission at 656 nm under excitation, 450 nm. The measured lifetimes (τmeas) of (5S2)5F4 level of Ho3+ doped ZFP glasses were obtained from decay profiles. The CIE color coordinates of Ho3+ doped ZFP glasses were calculated from emission spectra and 1.0 mol% of Ho3+ doped ZFP glass matrix gives green emission. Hence, these results confirm that the Ho3+ doped ZFP glasses could be considered as a promising candidate for visible green laser applications.

  10. Design and development of a blood vessel localization system using a Nir viewer; Diseno y desarrollo de un sistema de localizacion de vasos sanguineos mediante Visor NIR

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez R, A.; Plascencia C, L. E.; Cordova F, T.; Padilla R, N., E-mail: angelicahr@fisica.ugto.mx [Universidad de Guanajuato, 37150 Leon, Guanajuato (Mexico)

    2017-10-15

    In addition to the multiple applications of ionizing radiation in clinical diagnosis there is the possibility of using another part of the electromagnetic spectrum such as near infrared (Nir). This paper presents the design and construction of a Nir Biosensor in a range between 800 and 900 nm, which allows the visualization of blood vessels for the venepuncture procedure with the aim of reducing the trauma of venous access to patients of all ages. The possibility that the device is used in the location of venous ulcers as an alternative to veno grams obtained by X-rays is also explored. (Author)

  11. Strongly disordered superconductors

    International Nuclear Information System (INIS)

    Muttalib, K.A.

    1982-01-01

    We examine some universal effects of strong non-magnetic disorder on the electron-phonon and electron-electron interactions in a superconductor. In particular we explicitly take into account the effect of slow diffusion of electrons in a disordered medium by working in an exact impurity eigenstate representation. We find that the normal diffusion of electrons characterized by a constant diffusion coefficient does not lead to any significant correction to the electron-phonon or the effective electron-electron interactions in a superconductor. We then consider sufficiently strong disorder where Anderson localization of electrons becomes important and determine the effect of localization on the electron-electron interactions. We find that due to localization, the diffusion of electrons becomes anomalous in the sense that the diffusion coefficient becomes scale dependent. This results in an increase in the effective electron-electron interaction with increasing disorder. We propose that this provides a natural explanation for the unusual sensitivity of the transition temperature T/sub c/ of the high T/sub c/ superconductors (T/sub c/ > 10 0 K) to damage effects

  12. Strong Coupling Holography

    CERN Document Server

    Dvali, Gia

    2009-01-01

    We show that whenever a 4-dimensional theory with N particle species emerges as a consistent low energy description of a 3-brane embedded in an asymptotically-flat (4+d)-dimensional space, the holographic scale of high-dimensional gravity sets the strong coupling scale of the 4D theory. This connection persists in the limit in which gravity can be consistently decoupled. We demonstrate this effect for orbifold planes, as well as for the solitonic branes and string theoretic D-branes. In all cases the emergence of a 4D strong coupling scale from bulk holography is a persistent phenomenon. The effect turns out to be insensitive even to such extreme deformations of the brane action that seemingly shield 4D theory from the bulk gravity effects. A well understood example of such deformation is given by large 4D Einstein term in the 3-brane action, which is known to suppress the strength of 5D gravity at short distances and change the 5D Newton's law into the four-dimensional one. Nevertheless, we observe that the ...

  13. Synthesis of mixed ligand europium complexes: Verification of predicted luminescence intensification

    International Nuclear Information System (INIS)

    Lima, Nathalia B.D.; Silva, Anderson I.S.; Gonçalves, Simone M.C.; Simas, Alfredo M.

    2016-01-01

    Mixed ligand europium complexes are predicted to be more luminescent than what would be expected from their corresponding repeating ligand compounds according to a conjecture recently advanced by our research group; a conjecture that has already been validated for strongly luminescent europium complexes. In this article, we seek to further verify the validity of this conjecture for complexes which are much more symmetric, and which thus display lower levels of luminescence. Accordingly, we synthesized complexes Eu(DBM) 3 (L) 2 , and all novel mixed ligand combinations Eu(DBM) 3 (L,L') with L and L' equal to DBSO, PTSO, and TPPO. The syntheses were carried out via displacement reactions from the starting complex Eu(DBM) 3 (H 2 O) 2 , passing through the intermediates Eu(DBM) 3 (L) 2 and finally, by displacement of L by L', arriving at Eu(DBM) 3 (L,L'). The ligands L obey the following order of displacement TPPO>PTSO>DBSO>H 2 O, which had been previously described by our group. In the present article, we further show that this displacement order could have been predicted by Sparkle/RM1 thermochemical calculations. Subsequently, we determined the radiative decay rates, A rad , for all six compounds by photophysical measurements. As expected, results show that the measured A rad values for all novel mixed ligand complexes are larger than the average of the A rad values for the corresponding repeating ligand coordination compounds. In conclusion, the present article does broaden the scope of our conjecture, which enunciates that an increase in the diversity of ligands around the europium ion tends to intensify the luminescence. - Highlights: • Mixed ligand europium complexes are predicted to be more luminescent than repeating ligand ones. • Radiative decay rates increase with structural coordination asymmetry. • The non-ionic ligands displacement order in substitution reactions is TPPO>PTSO>DBSO>H 2 O. • Sparkle/RM1 correctly predicts the

  14. A new network of faint calibration stars from the near infrared spectrometer (NIRS) on the IRTS

    Science.gov (United States)

    Freund, Minoru M.; Matsuura, Mikako; Murakami, Hiroshi; Cohen, Martin; Noda, Manabu; Matsuura, Shuji; Matsumoto, Toshio

    1997-01-01

    The point source extraction and calibration of the near infrared spectrometer (NIRS) onboard the Infrared Telescope in Space (IRTS) is described. About 7 percent of the sky was observed during a one month mission in the range of 1.4 micrometers to 4 micrometers. The accuracy of the spectral shape and absolute values of calibration stars provided by the NIRS/IRTS were validated.

  15. Suitability of faecal near-infrared reflectance spectroscopy (NIRS) predictions for estimating gross calorific value

    Energy Technology Data Exchange (ETDEWEB)

    De la Roza-Delgado, B.; Modroño, S.; Vicente, F.; Martínez-Fernández, A.; Soldado, A.

    2015-07-01

    A total of 220 faecal pig and poultry samples, collected from different experimental trials were employed with the aim to demonstrate the suitability of Near Infrared Reflectance Spectroscopy (NIRS) technology for estimation of gross calorific value on faeces as output products in energy balances studies. NIR spectra from dried and grounded faeces samples were analyzed using a Foss NIRSystem 6500 instrument, scanning over the wavelength range 400-2500 nm. Validation studies for quantitative analytical models were carried out to estimate the relevance of method performance associated to reference values to obtain an appropriate, accuracy and precision. The results for prediction of gross calorific value (GCV) of NIRS calibrations obtained for individual species showed high correlation coefficients comparing chemical analysis and NIRS predictions, ranged from 0.92 to 0.97 for poultry and pig. For external validation, the ratio between the standard error of cross validation (SECV) and the standard error of prediction (SEP) varied between 0.73 and 0.86 for poultry and pig respectively, indicating a sufficiently precision of calibrations. In addition a global model to estimate GCV in both species was developed and externally validated. It showed correlation coefficients of 0.99 for calibration, 0.98 for cross-validation and 0.97 for external validation. Finally, relative uncertainty was calculated for NIRS developed prediction models with the final value when applying individual NIRS species model of 1.3% and 1.5% for NIRS global prediction. This study suggests that NIRS is a suitable and accurate method for the determination of GCV in faeces, decreasing cost, timeless and for convenient handling of unpleasant samples.. (Author)

  16. Association of Concurrent fNIRS and EEG Signatures in Response to Auditory and Visual Stimuli.

    Science.gov (United States)

    Chen, Ling-Chia; Sandmann, Pascale; Thorne, Jeremy D; Herrmann, Christoph S; Debener, Stefan

    2015-09-01

    Functional near-infrared spectroscopy (fNIRS) has been proven reliable for investigation of low-level visual processing in both infants and adults. Similar investigation of fundamental auditory processes with fNIRS, however, remains only partially complete. Here we employed a systematic three-level validation approach to investigate whether fNIRS could capture fundamental aspects of bottom-up acoustic processing. We performed a simultaneous fNIRS-EEG experiment with visual and auditory stimulation in 24 participants, which allowed the relationship between changes in neural activity and hemoglobin concentrations to be studied. In the first level, the fNIRS results showed a clear distinction between visual and auditory sensory modalities. Specifically, the results demonstrated area specificity, that is, maximal fNIRS responses in visual and auditory areas for the visual and auditory stimuli respectively, and stimulus selectivity, whereby the visual and auditory areas responded mainly toward their respective stimuli. In the second level, a stimulus-dependent modulation of the fNIRS signal was observed in the visual area, as well as a loudness modulation in the auditory area. Finally in the last level, we observed significant correlations between simultaneously-recorded visual evoked potentials and deoxygenated hemoglobin (DeoxyHb) concentration, and between late auditory evoked potentials and oxygenated hemoglobin (OxyHb) concentration. In sum, these results suggest good sensitivity of fNIRS to low-level sensory processing in both the visual and the auditory domain, and provide further evidence of the neurovascular coupling between hemoglobin concentration changes and non-invasive brain electrical activity.

  17. NIR techniques create added values for the pellet and biofuel industry.

    Science.gov (United States)

    Lestander, Torbjörn A; Johnsson, Bo; Grothage, Morgan

    2009-02-01

    A 2(3)-factorial experiment was carried out in an industrial plant producing biofuel pellets with sawdust as feedstock. The aim was to use on-line near infrared (NIR) spectra from sawdust for real time predictions of moisture content, blends of sawdust and energy consumption of the pellet press. The factors varied were: drying temperature and wood powder dryness in binary blends of sawdust from Norway spruce and Scots pine. The main results were excellent NIR calibration models for on-line prediction of moisture content and binary blends of sawdust from the two species, but also for the novel finding that the consumption of electrical energy per unit pelletized biomass can be predicted by NIR reflectance spectra from sawdust entering the pellet press. This power consumption model, explaining 91.0% of the variation, indicated that NIR data contained information of the compression and friction properties of the biomass feedstock. The moisture content model was validated using a running NIR calibration model in the pellet plant. It is shown that the adjusted prediction error was 0.41% moisture content for grinded sawdust dried to ca. 6-12% moisture content. Further, although used drying temperatures influenced NIR spectra the models for drying temperature resulted in low prediction accuracy. The results show that on-line NIR can be used as an important tool in the monitoring and control of the pelletizing process and that the use of NIR technique in fuel pellet production has possibilities to better meet customer specifications, and therefore create added production values.

  18. Multivariate NIR studies of seed-water interaction in Scots Pine Seeds (Pinus sylvestris L.)

    OpenAIRE

    Lestander, Torbjörn

    2003-01-01

    This thesis describes seed-water interaction using near infrared (NIR) spectroscopy, multivariate regression models and Scots pine seeds. The presented research covers classification of seed viability, prediction of seed moisture content, selection of NIR wavelengths and interpretation of seed-water interaction modelled and analysed by principal component analysis, ordinary least squares (OLS), partial least squares (PLS), bi-orthogonal least squares (BPLS) and genetic algorithms. The potenti...

  19. Measurement of soluble solids content in watermelon by Vis/NIR diffuse transmittance technique*

    OpenAIRE

    Tian, Hai-qing; Ying, Yi-bin; Lu, Hui-shan; Fu, Xia-ping; Yu, Hai-yan

    2007-01-01

    Watermelon is a popular fruit in the world with soluble solids content (SSC) being one of the major characteristics used for assessing its quality. This study was aimed at obtaining a method for nondestructive SSC detection of watermelons by means of visible/near infrared (Vis/NIR) diffuse transmittance technique. Vis/NIR transmittance spectra of intact watermelons were acquired using a low-cost commercially available spectrometer operating over the range 350~1000 nm. Spectra data were analyz...

  20. Luminescent Afterglow Behavior in the M2Si5N8: Eu Family (M = Ca, Sr, Ba

    Directory of Open Access Journals (Sweden)

    Koen Van den Eeckhout

    2011-05-01

    Full Text Available Persistent luminescent materials are able to emit light for hours after being excited. The majority of persistent phosphors emit in the blue or green region of the visible spectrum. Orange- or red-emitting phosphors, strongly desired for emergency signage and medical imaging, are scarce. We prepared the nitrido-silicates Ca2Si5N8:Eu (orange, Sr2Si5N8:Eu (reddish, Ba2Si5N8:Eu (yellowish orange, and their rare-earth codoped variants (R = Nd, Dy, Sm, Tm through a solid state reaction, and investigated their luminescence and afterglow properties. In this paper, we describe how the persistent luminescence is affected by the type of codopant and the choice and ratio of the starting products. All the materials exhibit some form of persistent luminescence, but for Sr2Si5N8:Eu,R this is very weak. In Ba2Si5N8:Eu the afterglow remains visible for about 400 s, and Ca2Si5N8:Eu,Tm shows the brightest and longest afterglow, lasting about 2,500 s. For optimal persistent luminescence, the dopant and codopant should be added in their fluoride form, in concentrations below 1 mol%. A Ca3N2 deficiency of about 5% triples the afterglow intensity. Our results show that Ba2Si5N8:Eu(,R and Ca2Si5N8:Eu(,R are promising persistent phosphors for applications requiring orange or red light.

  1. Effects of nanostructuring on luminescence properties of SrS:Ce,Sm phosphor: An experimental and phenomenological study

    Science.gov (United States)

    Yazdanmehr, Mohsen; Sadeghi, Hossein; Tehrani, Masoud Kavosh; Hashemifar, Seyed Javad; Mahdavi, Mohammad

    2018-01-01

    In this work, we employ various experimental techniques to illustrate the effects of nanostructuring on improvement of the luminescence properties of the polycrystalline SrS co-activated by cerium and samarium dopants (SrS : Ce , Sm). The nano and microstructure SrS : Ce , Sm powders were synthesized by the co-precipitation and solid state diffusion methods, respectively, followed by the spark plasma sintering (SPS) process to densify powders into pellet shape. It is observed that the photo-luminescence (PL), radio-luminescence (RL), and optically stimulated luminescence (OSL) emission intensity of the nanostructure samples are significantly improved with respect to the microstructure samples. Moreover, by using an accurate photomultiplier tube, we measured the CW-OSL decay curves of the samples to demonstrate much higher and faster sensitivity of the nanostructure SrS : Ce , Sm for in-flight and online OSL radiation dosimetry. The obtained absorption and emission spectra are used for phenomenology of the electronic band structure of the SrS : Ce , Sm micro and nano-phosphors inside the band gap. The proposed phenomenological electronic structures are then used to clarify the role of Ce3+ and Sm3+ localized energy levels in the luminescence properties of the nano and microstructure samples. It is argued that electronic transitions from the 2T2g state of Ce3+ and the 4G5/2 state of Sm3+ have strong contribution to the PL and RL emission spectra, while in the OSL mechanism, the Sm3+ 4G5/2 state is mainly responsible for electrons trapping.

  2. 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

  3. Bright white upconversion luminescence from Er3+/Tm3+/Yb3+-doped titanate-based glasses prepared by aerodynamic levitation method

    Science.gov (United States)

    Zhang, Minghui; Yu, Jianding; Jiang, Wan; Liu, Yan; Ai, Fei; Wen, Haiqin; Jiang, Meng; Yu, Huimei; Pan, Xiuhong; Tang, Meibo; Gai, Lijun

    2017-10-01

    Aerodynamic levitation method was employed to prepare Er3+/Tm3+/Yb3+-doped titanate-based glasses. DTA results show that the glass performs high thermal stability with the glass transition temperature of 799 °C. The interaction among rare earth ions has been discussed by adjusting the relative concentration. Er3+ ions can quench the upconversion luminescence of Tm3+ ions. Tm3+ ions play a strong role in quenching the emissions of Er3+ and Tm3+ when the content of Tm3+ ions is greater than or equal 0.05. From the view of the ratio of red emission to green emission, Tm3+ ions can improve the red emission of Er3+ ions to some extent in contrast with the green emissions of Er3+ ions. 980 nm incident laser can be efficiently absorbed by Yb3+ ions. The relative intensity of red, green, and blue upconversion luminescence has been tuned to obtain white light. The composition with white upconversion luminescence of the color coordinate (0.291, 0.3292) has been found. Moreover, white upconversion luminescence mechanism is a two-photon process of ET, ESA, and cooperative sensitization. Rare earth ions doped titanate-based glasses with bright upconversion luminescence perform potential applications in color display, back light, et al.

  4. Detection of irradiated food using photostimulated luminescence

    International Nuclear Information System (INIS)

    Malec-Czechowska, K.; Stachowicz, W.

    2005-01-01

    Detection of irradiated spices, dried mushrooms and flavour blends using photostimulated luminescence (PSL) is presented. PSL measurements were carried out as described in standard PN-EN 13751. A lower threshold (T 1 700 counts/60s) and an upper threshold (T 2 = 5000 counts/60s) were used to classify the sample. PSL intensities below the threshold were classified as from non-irradiated samples and PSL signals above the upper threshold were regarded from irradiated samples. Signal levels between the two thresholds were classified as intermediate, showing that further investigations are necessary. The PSL tests were carried out at Institute Nutritional Physiology, Federal Research Centre for Nutrition in Karlsruhe with a SURRAC PPSL Iradiated food screening system (SURRAC, Glasgow, UK). (author)

  5. Delayed Luminescence and Biophotons from Biological Materials

    Science.gov (United States)

    Knoesel, Ernst; Hann, Patrick; Garzon, Maria; Pfeiffer, Erik; Lofland, Samuel

    2008-03-01

    There has recently been increased interest in the field of biophotonics, since it is a non-invasive technique. Many biological systems, such as yeast, bacteria, leaves, seeds, and algae display the unusual phenomenon of a weak, delayed luminescence on the timescale of seconds to minutes after transient illumination. It is also observed that the time decay of the biophotonic emission is not exponential, even after the delay, and that there can be oscillations in intensity with time, which depend on the duration of the illumination. Results from two types of yeast, i.e. bread yeast, and saccharomyces, as well as those from several types of algae are presented. Possible mechanisms for the source of the ultraweak photon emission are discussed.

  6. Sono-luminescence and nuclear fusion

    International Nuclear Information System (INIS)

    Seife, Ch.; Hilgenfeldt, S.; Lohse, D.

    2002-01-01

    This article presents multi-bubble and single-bubble luminescence. Since long scientists have known that ultra-sound waves could trigger the formation of bubbles in water (phenomenon called cavitation) but in 1930, for the first time experiments showed that these bubbles could emit light in particular conditions. In 1989 F. Gaitan succeeded in trapping a single bubble by using stationary ultra-sound waves, this bubble was exploding 20.000 times per second according to the frequency of the wave while emitting a series of flashes of light. Some scientists thought that the gas inside the bubble could reach very high values of temperature and pressure, and proposed the possibility of nuclear fusion to explain the excess of neutrons that has been evidenced in a cavitation experiment with deuterated acetone. The last part of this article describes the controversy triggered by the article describing this experiment, that was published by 'Science' in march 2002. (A.C.)

  7. Metal luminescence in a bright disintegrated prominence

    International Nuclear Information System (INIS)

    Yakovkin, N.A.; Zel'dina, M.Yu.; Rakhubovskij, A.S.; AN Ukrainskoj SSR, Kiev. Glavnaya Astronomicheskaya Observatoriya)

    1975-01-01

    It is found that Na, Mg, Ca, Sc, Ti, Fe, Sr, and Ba contents in a protuberance relative to the hydrogen content is about the same as in photosphere and chromosphere (except for the Na abundance). The metals are in the state of single ionization with the exception of calcium [Ca ++ ] approximately [Ca + ], strontium [Sr ++ ] = 0.5 [Sr + ], and barium [Ba ++ ] = 6Ba + , whose secondary ionization occurs from metastable states by Lsub(α)-emission in the protuberance. The Lsub(α)-emission ionizes neutral iron as well. Primary ionization of remaining metals is performed by the solar near ultraviolet. Luminescence in metal lines is provided by the photosphere emission scattering, and only H and KCa + lines are excited by electron impacts

  8. Detection of irradiated prawns by photostimulated luminescence

    International Nuclear Information System (INIS)

    Chen, Susu; Saito, Kimie; Hagiwara, Shoji; Todoriki, Setsuko; Nakajima, Mitsutoshi

    2011-01-01

    The purpose of this study was to investigate how photostimulated luminescence (PSL) can be applied to verify whether prawns have been irradiated by analyzing their intestinal tracts. Prawns from five different locations which were irradiated at doses of 1 kGy of γ-radiations were analyzed using the Japanese model PSL system. The results showed that the integrated photon counts of all the irradiated samples exceeded the upper threshold value (T 2 =4000 counts/90 s), whereas those of the non-irradiated samples were blew than the lower threshold value (T 1 =1000 counts/90 s). Moreover, using the other parameters which were decrease of intensity after optically stimulation and increase of intensity by optically stimulation, a clear difference was observed between non-irradiated and 1 kGy irradiated samples. Therefore, the Japanese model PSL system can be used as a screening method for detecting irradiated prawns by analyzing their intestinal tracts. (author)

  9. Luminescence properties of lustre decorated majolica

    Science.gov (United States)

    Galli, A.; Martini, M.; Sibilia, E.; Padeletti, G.; Fermo, P.

    Luminescence measurements have been performed on several Italian Renaissance ceramic shards produced in central Italy, as well as on some others from Hispano-Moresque and Fatimid periods. The aim of this study was the characterisation of the raw materials used to manufacture lustre decorated majolica. At first, the thermoluminescence (TL) dating of all ceramic bodies was performed, because the shards lacked sure chronological attribution, having been provided by private collectors, or found during emergency restoration works or archaeological surveys. To characterise the defects and the recombination centers of the different components of the ceramics (ceramic body, glaze, glaze, and lustre), radioluminescence (RL) measurements have been performed on samples representative of each historical period. The dating results are reported, as well as the preliminary RL results.

  10. Luminescent solar concentrators utilizing stimulated emission.

    Science.gov (United States)

    Kaysir, Md Rejvi; Fleming, Simon; MacQueen, Rowan W; Schmidt, Timothy W; Argyros, Alexander

    2016-03-21

    Luminescent solar concentrators (LSCs) are an emerging technology that aims primarily to reduce the cost of solar energy, with great potential for building integrated photovoltaic (PV) structures. However, realizing LSCs with commercially viable efficiency is currently hindered by reabsorption losses. Here, we introduce an approach to reducing reabsorption as well as improving directional emission in LSCs by using stimulated emission. Light from a seed laser (potentially an inexpensive laser diode) passes through the entire area of the LSC panel, modifying the emission spectrum of excited dye molecules such that it is spectrally narrower, at wavelengths that minimize reabsorption to allow net gain in the system, and directed towards a small PV cell. A mathematical model, taking into account thermodynamic considerations, of such a system is presented which identifies key parameters and allows evaluation in terms of net effective output power.

  11. Sol–gel synthesis and luminescence of undoped and Mn-doped zinc orthosilicate phosphor nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    El Ghoul, J., E-mail: ghoultn@yahoo.fr [Laboratoire de Physique des Matériaux et des Nanomatériaux Appliquée à l’Environnement, Faculté des Sciences de Gabès, Cité Erriadh Manara Zrig, 6072 Gabès (Tunisia); El Mir, L. [Laboratoire de Physique des Matériaux et des Nanomatériaux Appliquée à l’Environnement, Faculté des Sciences de Gabès, Cité Erriadh Manara Zrig, 6072 Gabès (Tunisia); Al Imam Mohammad Ibn Saud Islamic University (IMSIU), College of Sciences, Departement of Physics, Riyadh 11623 (Saudi Arabia)

    2014-04-15

    Zn{sub 2}SiO{sub 4} and Zn{sub 2}SiO{sub 4}:Mn particles embedded in SiO{sub 2} host matrix prepared by sol gel method under supercritical conditions of ethyl alcohol in two steps. Were prepared by a simple solid-phase reaction under natural atmosphere at 1200 °C after the incorporation of ZnO and ZnO:Mn nanoparticles, respectively, in silica monolith. In the case of SiO{sub 2}/Zn{sub 2}SiO{sub 4} nanocomposite, the powder with an average particle size of 80 nm shows a strong luminescence band centred at around 760 nm in the visible range. In addition, the PL spectrum for the SiO{sub 2}/Zn{sub 2}SiO{sub 4}:Mn nanocomposite showed that a dominant peak at 525 nm appeared, which originated from the {sup 4}T{sub 1}–{sup 6}A{sub 1} transitions of Mn{sup 2+} ions. The luminescence properties of nanocomposites were characterized by emission and excitation spectra as well their dependencies of upon temperature and power excitation density. -- Highlights: • The Synthesis of Zn{sub 2}SiO{sub 4} nanocomposites. • Structural and optical characterizations of Zn{sub 2}SiO{sub 4} and Zn{sub 2}SiO{sub 4}:Mn nanocomposites. • The willemite α-Zn{sub 2}SiO{sub 4} structure was formed to the heat treatment temperature 1200 °C. • The powder exhibits a nanometric size. • Strong bands of luminescence have appeared.

  12. 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.

  13. 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.

  14. Fluorescence detection of glutathione and oxidized glutathione in blood with a NIR-excitable cyanine probe

    Science.gov (United States)

    Liu, Chang-hui; Qi, Feng-pei; Wen, Fu-bin; Long, Li-ping; Liu, Ai-juan; Yang, Rong-hua

    2018-04-01

    Cyanine has been widely utilized as a near infrared (NIR) fluorophore for detection of glutathione (GSH). However, the excitation of most of the reported cyanine-based probes was less than 800 nm, which inevitably induce biological background absorption and lower the sensitivity, limiting their use for detection of GSH in blood samples. To address this issue, here, a heptamethine cyanine probe (DNIR), with a NIR excitation wavelength at 804 nm and a NIR emission wavelength at 832 nm, is employed for the detection of GSH and its oxidized form (GSSG) in blood. The probe displays excellent selectivity for GSH over GSSG and other amino acids, and rapid response to GSH, in particular a good property for indirect detection of GSSG in the presence of enzyme glutathione reductase and the reducing agent nicotinamideadenine dinucleotide phosphate, without further separation prior to fluorescent measurement. To the best of our knowledge, this is the first attempt to explore NIR fluorescent approach for the simultaneous assay of GSH and GSSG in blood. As such, we expect that our fluorescence sensors with both NIR excitation and NIR emission make this strategy suitable for the application in complex physiological systems.

  15. Heterologous expression of the Aspergillus nidulans regulatory gene nirA in Fusarium oxysporum.

    Science.gov (United States)

    Daboussi, M J; Langin, T; Deschamps, F; Brygoo, Y; Scazzocchio, C; Burger, G

    1991-12-20

    We have isolated strains of Fusarium oxysporum carrying mutations conferring a phenotype characteristic of a loss of function in the regulatory gene of nitrate assimilation (nirA in Aspergillus nidulans, nit-4 in Neurospora crassa). One of these nir- mutants was successfully transformed with a plasmid containing the nirA gene of A. nidulans. The nitrate reductase of the transformants is still inducible, although the maximum activity is lower than in the wild type. Single and multiple integration events were found, as well as a strict correlation between the presence of the nirA gene and the Nir+ phenotype of the F. oxysporum transformants. We also investigated how the A. nidulans structural gene (niaD) is regulated in F. oxysporum. Enzyme assays and Northern experiments show that the niaD gene is subject to nitrate induction and that it responds to nitrogen metabolite repression in a F. oxysporum genetic background. This indicates that both the mechanisms of specific induction, mediated by a gene product isofunctional to nirA, and nitrogen metabolite repression, presumably mediated by a gene product isofunctional to the homologous gene of A. nidulans, are operative in F. oxysporum.

  16. 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.

  17. Thermo-optical properties of optically stimulated luminescence in feldspars

    DEFF Research Database (Denmark)

    Poolton, N.R.J.; Bøtter-Jensen, L.; Johnsen, O.

    1995-01-01

    Optically stimulated luminescence processes in feldspars are subject to competing thermal enhancement and quenching processes: this article describes the thermal enhancement effects for orthoclase, albite and plagioclase feldspars. It is demonstrated that certain lattice vibrational modes can be ...

  18. 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.

  19. Examination of the picture properties of luminescence memory foils

    International Nuclear Information System (INIS)

    Ewert, U.; Heine, S.; Nockemann, C.; Stade, J.; Tillack, G.R.; Wessel, H.; Zscherpel, U.; Mattis, A.

    1995-01-01

    Luminescence memory foils are a new medium for radiography without films. They are known by the name of image plates or digital memory foils. The suitability of such systems for industrial radiography is examined. (orig.) [de

  20. Negative luminescence and devices based on this phenomenon

    International Nuclear Information System (INIS)

    Ivanov-Omskii, V. I.; Matveev, B. A.

    2007-01-01

    Recent publications concerned with infrared emitters whose electrical modulation results in absorption of radiation detected as negative luminescence are reviewed. The main properties of the devices based on this phenomenon are analyzed

  1. Negative luminescence and devices based on this phenomenon

    Energy Technology Data Exchange (ETDEWEB)

    Ivanov-Omskii, V I; Matveev, B. A. [Russian Academy of Sciences, Ioffe Physicotechnical Institute (Russian Federation)], E-mail: bmat@iropt3.ioffe.rssi.ru

    2007-03-15

    Recent publications concerned with infrared emitters whose electrical modulation results in absorption of radiation detected as negative luminescence are reviewed. The main properties of the devices based on this phenomenon are analyzed.

  2. Renewable energy : better luminescent solar panels in prospect

    NARCIS (Netherlands)

    Debije, M.G.

    2015-01-01

    Devices known as luminescent solar concentrators could find use as renewable-energy generators, but have so far been plagued by a major light-reabsorption effect. A new study offers a promising route to tackling this problem

  3. LIGO: The strong belief

    CERN Multimedia

    Antonella Del Rosso

    2016-01-01

    Twenty years of designing, building and testing a number of innovative technologies, with the strong belief that the endeavour would lead to a historic breakthrough. The Bulletin publishes an abstract of the Courier’s interview with Barry Barish, one of the founding fathers of LIGO.   The plots show the signals of gravitational waves detected by the twin LIGO observatories at Livingston, Louisiana, and Hanford, Washington. (Image: Caltech/MIT/LIGO Lab) On 11 February, the Laser Interferometer Gravitational-Wave Observatory (LIGO) and Virgo collaborations published a historic paper in which they showed a gravitational signal emitted by the merger of two black holes. These results come after 20 years of hard work by a large collaboration of scientists operating the two LIGO observatories in the US. Barry Barish, Linde Professor of Physics, Emeritus at the California Institute of Technology and former Director of the Global Design Effort for the Internat...

  4. Strongly interacting Higgs bosons

    International Nuclear Information System (INIS)

    Appelquist, T.; Bernard, C.

    1980-01-01

    The sensitivity of present-energy weak interactions to a strongly interacting heavy-Higgs-boson sector is discussed. The gauged nonlinear sigma model, which is the limit of the linear model as the Higgs-boson mass goes to infinity, is used to organize and catalogue all possible heavy-Higgs-boson effects. As long as the SU(2)/sub L/ x SU(2)/sub R/ symmetry of the Higgs sector is preserved, these effects are found to be small, of the order of the square of the gauge coupling times logarithms (but not powers) of the Higgs-boson mass divided by the W mass. We work in the context of a simplified model with gauge group SU(2)/sub L/; the extension to SU(2)/sub L/ x U(1) is briefly discussed

  5. Influence of excitonic effects on luminescence quantum yield in silicon

    Energy Technology Data Exchange (ETDEWEB)

    Sachenko, A.V.; Kostylyov, V.P.; Vlasiuk, V.M. [V. Lashkaryov Institute of Semiconductor Physics, NAS of Ukraine, 41 prospect Nauky, 03028 Kyiv (Ukraine); Sokolovskyi, I.O., E-mail: isokolovskyi@mun.ca [V. Lashkaryov Institute of Semiconductor Physics, NAS of Ukraine, 41 prospect Nauky, 03028 Kyiv (Ukraine); Department of Physics and Physical Oceanography, Memorial University of Newfoundland, St. John' s, NL, A1B 3X7 Canada (Canada); Evstigneev, M. [Department of Physics and Physical Oceanography, Memorial University of Newfoundland, St. John' s, NL, A1B 3X7 Canada (Canada)

    2017-03-15

    Nonradiative exciton lifetime in silicon is determined by comparison of the experimental and theoretical curves of bulk minority charge carriers lifetime on doping and excitation levels. This value is used to analyze the influence of excitonic effects on internal luminescence quantum yield at room temperature, taking into account both nonradiative and radiative exciton lifetimes. A range of Shockley-Hall-Reed lifetimes is found, where excitonic effects lead to an increase of internal luminescence quantum yield.

  6. 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

  7. Optical and luminescent properties of the lead and barium molybdates

    Energy Technology Data Exchange (ETDEWEB)

    Spassky, D.A. E-mail: dima@opts.phys.msu.ru; Ivanov, S.N.; Kolobanov, V.N.; Mikhailin, V.V.; Zemskov, V.N.; Zadneprovski, B.I.; Potkin, L.I

    2004-12-01

    Time-resolved luminescence as well as excitation and reflectivity spectra of the oriented lead and barium molybdate single crystals were studied using synchrotron radiation. Features in reflectivity spectra in the fundamental absorption region were analyzed. The contribution of electronic states of lead cation to the formation of the bandgap in PbMoO{sub 4} is supposed. The role of lead states in the intrinsic luminescence of PbMoO{sub 4} is discussed.

  8. 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.

  9. 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.

  10. [Determination of Chloride Salt Solution by NIR Spectroscopy].

    Science.gov (United States)

    Zhang, Bin; Chen, Jian-hong; Jiao, Ming-xing

    2015-07-01

    Determination of chloride salt solution by near infrared spectrum plays a very important role in Biomedicine. The near infrared spectrum analysis of Sodium chloride, potassium chloride, calcium chloride aqueous solution shows that the concentration change of chloride salt can affect hydrogen bond, resulting in the variation of near infrared spectrum of water. The temperature influence on NIR spectrum has been decreased by choosing reasonable wavelength range and the wavelength where the temperature effects are zero (isosbestic point). Chlorine salt prediction model was established based on partial least squares method and used for predicting the concentration of the chlorine ion. The impact on near infrared spectrum of the cation ionic radius, the number of ionic charge, the complex effect of ionic in water has also discussed in this article and the reason of every factor are analysed. Experimental results show that the temperature and concentration will affect the near-infrared spectrum of the solution, It is found that the effect of temperature plays the dominant role at low concentrations of chlorine salt; rather, the ionic dominates at high concentration. Chloride complexes are formed in aqueous solution, It has an effect on hydrogen bond of water combining with the cations in chlorine salt solution, Comparing different chloride solutions at the same concentration, the destruction effects of chloride complexes and catnions on the hydrogen bond of water increases in the sequences: CaCl2 >NaCl>KC. The modeling result shows that the determination coefficients (R2) = 99.97%, the root mean square error of cross validation (RM- SECV) = 4.51, and the residual prediction deviation (RPD) = 62.7, it meets the daily requirements of biochemical detection accuracy.

  11. Cost Effective Process Monitoring using UV-VIS-NIR Spectroscopy

    International Nuclear Information System (INIS)

    Cipiti, B.; McDaniel, M.; Bryan, S.; Pratt, S.

    2015-01-01

    UV-VIS-NIR Spectroscopy is a simple and inexpensive measurement technology which has been proposed for process monitoring applications at reprocessing plants. The purpose of this work was to examine if spectroscopy could replace more costly analytical measurements to reduce the safeguards burden to the operator or inspector. Recognizing that the higher measurement uncertainty of spectroscopy makes it unsuited for the accountability tanks, the approach instead was to focus on replacing mass spectrometry for random samples that are taken in a plant. The Interim Inventory Verification and Short Inventory Verification (IIV/SIV) at the Rokkasho Reprocessing Plant utilize random sampling of internal process vessels and laboratory measurement using Isotope Dilution Mass Spectrometry (IDMS) to account for plutonium on a timely basis. These measurements are time-consuming, and the low uncertainty may not always be required. For this work, modelling was used to examine if spectroscopy could be used without adversely affecting the safeguards of the plant. The Separation and Safeguards Performance Model (SSPM), developed at Sandia National Laboratories, was utilized to examine the replacement of IDMS measurements with spectroscopy. Modeling results showed that complete replacement of IDMS with spectroscopy lowered the detection probability for diversion by an unacceptable amount. However, partial replacement (only for samples from vessels with low plutonium content) did not adversely affect the detection probability. This partial replacement covers roughly half of the twenty or so sampling points used for the IIV/SIVA cost-benefit analysis was completed to determine the cost savings that this approach can provide based on lower equipment costs, maintenance, and reduction of analysts' time. This work envisions working with the existing sampling system and performing the spectroscopic measurements in the analytical laboratory, but future work could examine incorporating

  12. Investigation of blue luminescence in Mg-doped nonpolar a-plane GaN

    International Nuclear Information System (INIS)

    Kim, Hogyoung; Song, Keun Man

    2014-01-01

    The temperature-dependent optical characteristics of blue luminescence (BL) band in Mg-doped nonpolar a-plane GaN films were investigated using photoluminescence (PL) measurements. For the sample with the highest Cp 2 Mg/TMGa ([Mg]/[Ga]) molar ratio, the BL band was shown to have two distinct peaks, one at about 2.95 eV and the other at about 2.75 eV, which were associated with the donor–acceptor pair (DAP) transitions between the one shallow Mg acceptor level and the two different deep donor levels. In contrast, a single broad BL band was observed for all other samples. Strong potential fluctuations caused by high compensation level in the sample with the highest [Mg]/[Ga] molar ratio might localize the carriers related to the 2.75 eV band, leading to the different emission characteristics in BL band as compared to other samples. -- Highlights: • The temperature-dependent optical characteristics of blue luminescence (BL) in Mg-doped nonpolar a-plane GaN were investigated using photoluminescence (PL) measurements. • At the highest [Mg]/[Ga] molar ratio, the BL was observed to have two distinct peaks at low temperatures. • The BL was associated with the one shallow Mg acceptor level and the two different Mg-related deep donor levels. • Strong potential fluctuations caused by high compensation level might localize the carriers

  13. Investigation of blue luminescence in Mg-doped nonpolar a-plane GaN

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hogyoung [Department of Optometry, Seoul National University of Science and Technology, Seoul 139-743 (Korea, Republic of); Song, Keun Man, E-mail: skmmec@gmail.com [Korea Advanced Nano Fab Center, Suwon, Gyeonggi 443-770 (Korea, Republic of)

    2014-01-15

    The temperature-dependent optical characteristics of blue luminescence (BL) band in Mg-doped nonpolar a-plane GaN films were investigated using photoluminescence (PL) measurements. For the sample with the highest Cp{sub 2}Mg/TMGa ([Mg]/[Ga]) molar ratio, the BL band was shown to have two distinct peaks, one at about 2.95 eV and the other at about 2.75 eV, which were associated with the donor–acceptor pair (DAP) transitions between the one shallow Mg acceptor level and the two different deep donor levels. In contrast, a single broad BL band was observed for all other samples. Strong potential fluctuations caused by high compensation level in the sample with the highest [Mg]/[Ga] molar ratio might localize the carriers related to the 2.75 eV band, leading to the different emission characteristics in BL band as compared to other samples. -- Highlights: • The temperature-dependent optical characteristics of blue luminescence (BL) in Mg-doped nonpolar a-plane GaN were investigated using photoluminescence (PL) measurements. • At the highest [Mg]/[Ga] molar ratio, the BL was observed to have two distinct peaks at low temperatures. • The BL was associated with the one shallow Mg acceptor level and the two different Mg-related deep donor levels. • Strong potential fluctuations caused by high compensation level might localize the carriers.

  14. Phase transformation, morphology evolution and luminescence property variation in Y2O3: Eu hollow microspheres

    International Nuclear Information System (INIS)

    Wang, Qin; Guo, Jing; Jia, Wenjing; Liu, Baocang; Zhang, Jun

    2012-01-01

    Highlights: ► We report a general and facile method for the synthesis of Y 2 O 3 : Eu hollow microspheres. ► This method may be of great significance in the synthesis of many other hollow spherical materials. ► Phase, morphology and luminescence property were found to be strongly dependent on temperature and pH. ► The evolution process under various temperatures and pH values were discussed. ► The sample shows a strong red emission under short UV irradiation, and the lifetime is determined to be 7.0 ms. - Abstract: Y 2 O 3 : Eu hollow microspheres with average size of 500–600 nm have been successfully synthesized via a solvothermal method in the presence of sodium citrate as surfactant followed by a subsequent heat treatment process. High polymer F127(EO 106 PO 70 EO 106 ) served as a soft template in the formation of as prepared hollow microspheres. It is found that the pH values and the reaction temperature are two crucial factors in determining the phase, morphology and luminescence properties of the Y 2 O 3 : Eu hollow microspheres. Morphology evolution can be achieved by changing the pH and the reaction temperature. The properties of the Eu 3+ -doped Y 2 O 3 : Eu nanocrystals were characterized by XRD, FE-SEM, HR-TEM and UV–vis spectroscopy.

  15. Novel Sr{sub 2}LuF{sub 7}–SiO{sub 2} nano-glass-ceramics: Structure and up-conversion luminescence

    Energy Technology Data Exchange (ETDEWEB)

    Yanes, A.C.; Castillo, J. del, E-mail: fjvargas@ull.edu.es; Luis, D.; Puentes, J.

    2016-02-15

    Novel transparent nano-glass-ceramics comprising RE-doped Sr{sub 2}LuF{sub 7} nanocrystals have been obtained by thermal treatment of precursor sol–gel glasses. The precipitated Sr{sub 2}LuF{sub 7} nanocrystals with sizes from 4.5 to 11.5 nm, confirmed by X-Ray Diffraction and Transmission Electron Microscopy images, show a cubic phase structure. The luminescent features of Eu{sup 3+} ions, used as structural probes, evidence the distribution of RE ions into the fluoride nanocrystals. Under 980 nm laser excitation, intense UV, vis and NIR up-conversion emissions were observed and studied in Yb{sup 3+}–Tm{sup 3+}, Yb{sup 3+}–Er{sup 3+} and Yb{sup 3+}–Ho{sup 3+} co-doped nano-glass-ceramics. These results suggest considering these nano-glass-ceramics for potential optical applications as high efficient UV up-conversion materials in UV solid state lasers, infrared tuneable phosphors and photonic integrated devices. - Highlights: • Novel sol-gel glass-ceramics with RE{sup 3+}-Sr{sub 2}LuF{sub 7} doped nanocrystals were obtained. • Eu{sup 3+} probe ion was used to distinguish between amorphous and crystalline environments. • The incorporation of an important fraction of RE ions into nanocrystals was confirmed. • Under 980 nm excitation, intense UV-vis-NIR up-conversion emissions were observed.

  16. Luminescence of Er3+ doped double lead halide crystals under X-ray, UV, VIS and IR excitation

    Science.gov (United States)

    Serazetdinov, A. R.; Smirnov, A. A.; Pustovarov, V. A.; Isaenko, L. I.

    2017-09-01

    Er3+ doped double lead halide crystals incorporate a number of properties making them interesting for practical use in light conducting materials. X-ray excited luminescence (XRL) spectra, photoluminescence (PL) spectra in region of 1.5-3.5 eV, photoluminescence excitation (PLE) spectra (2.75-5 eV) and anti-stokes luminescence (ASL) spectra were measured at room temperature in KPb2Cl5 (KPC) and RbPb2Br5 (RPB) matrices doped with Er3+ (1%) ions and in KPC doped with Er3++ Yb3+ ions(1:3 ratio concentration). Intraconfigurational f→f transitions are observed in Er3+ ions in most of the cases. The concrete spectrum form is strongly dependent on the excitation energy. Under 980 nm excitation upper Er3+ levels are excited, showing upconversional processes. In case of 313 nm (UV) and 365 nm (VIS) excitation self trapped exciton luminescence was detected in RPB crystal. Additional Yb3+ doping ions strongly increase quantum yield under 980 nm excitation and this doping cause insignificant influence on quantum yield under VIS or UV excitation.

  17. Strong-interaction nonuniversality

    International Nuclear Information System (INIS)

    Volkas, R.R.; Foot, R.; He, X.; Joshi, G.C.

    1989-01-01

    The universal QCD color theory is extended to an SU(3) 1 direct product SU(3) 2 direct product SU(3) 3 gauge theory, where quarks of the ith generation transform as triplets under SU(3)/sub i/ and singlets under the other two factors. The usual color group is then identified with the diagonal subgroup, which remains exact after symmetry breaking. The gauge bosons associated with the 16 broken generators then form two massive octets under ordinary color. The interactions between quarks and these heavy gluonlike particles are explicitly nonuniversal and thus an exploration of their physical implications allows us to shed light on the fundamental issue of strong-interaction universality. Nonuniversality and weak flavor mixing are shown to generate heavy-gluon-induced flavor-changing neutral currents. The phenomenology of these processes is studied, as they provide the major experimental constraint on the extended theory. Three symmetry-breaking scenarios are presented. The first has color breaking occurring at the weak scale, while the second and third divorce the two scales. The third model has the interesting feature of radiatively induced off-diagonal Kobayashi-Maskawa matrix elements

  18. John Strong (1941 - 2006)

    CERN Multimedia

    Wickens, F

    Our friend and colleague John Strong was cruelly taken from us by a brain tumour on Monday 31st July, a few days before his 65th birthday John started his career working with a group from Westfield College, under the leadership of Ted Bellamy. He obtained his PhD and spent the early part of his career on experiments at Rutherford Appleton Laboratory (RAL), but after the early 1970s his research was focussed on experiments in CERN. Over the years he made a number of notable contributions to experiments in CERN: The Omega spectrometer adopted a system John had originally developed for experiments at RAL using vidicon cameras to record the sparks in the spark chambers; He contributed to the success of NA1 and NA7, where he became heavily involved in the electronic trigger systems; He was responsible for the second level trigger system for the ALEPH detector and spent five years leading a team that designed and built the system, which ran for twelve years with only minor interventions. Following ALEPH he tur...

  19. Stirring Strongly Coupled Plasma

    CERN Document Server

    Fadafan, Kazem Bitaghsir; Rajagopal, Krishna; Wiedemann, Urs Achim

    2009-01-01

    We determine the energy it takes to move a test quark along a circle of radius L with angular frequency w through the strongly coupled plasma of N=4 supersymmetric Yang-Mills (SYM) theory. We find that for most values of L and w the energy deposited by stirring the plasma in this way is governed either by the drag force acting on a test quark moving through the plasma in a straight line with speed v=Lw or by the energy radiated by a quark in circular motion in the absence of any plasma, whichever is larger. There is a continuous crossover from the drag-dominated regime to the radiation-dominated regime. In the crossover regime we find evidence for significant destructive interference between energy loss due to drag and that due to radiation as if in vacuum. The rotating quark thus serves as a model system in which the relative strength of, and interplay between, two different mechanisms of parton energy loss is accessible via a controlled classical gravity calculation. We close by speculating on the implicati...

  20. 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