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Sample records for co-operative downconversion luminescence

  1. Spectroscopic studies and downconversion luminescence in OH{sup −}-free Pr{sup 3+}–Yb{sup 3+} co-doped low-silica calcium aluminosilicate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Borrero-González, L.J., E-mail: borrero.luis@gmail.com [Instituto de Física de São Carlos, Universidade de São Paulo, CP 369, 13560-970, São Carlos, SP (Brazil); Nunes, L.A.O. [Instituto de Física de São Carlos, Universidade de São Paulo, CP 369, 13560-970, São Carlos, SP (Brazil); Carmo, J.L.; Astrath, F.B.G.; Baesso, M.L. [Departamento de Física, Universidade Estadual de Maringá, Av. Colombo, 5790, 87020-900 Maringá, PR (Brazil)

    2014-01-15

    We report on spectroscopic studies and downconversion luminescence in OH{sup −}-free Pr{sup 3+}–Yb{sup 3+} co-doped low-silica calcium aluminosilicate glasses (LSCAS). The dependencies of the visible to near-infrared emissions, photoacoustic signals, luminescence decay times and energy transfer efficiencies from Pr{sup 3+}→Yb{sup 3+} on the doped Yb{sub 2}O{sub 3} concentration were investigated. The results confirmed the occurrence of downconversion processes in the examined samples, followed by a back-energy transfer mechanism from the Yb{sup 3+}:{sup 2}F{sub 5/2} level to the Pr{sup 3+}:{sup 1}G{sub 4} level, from where the multiphonon relaxations through the {sup 1}G{sub 4},{sup 3}F{sub 4}→{sup 3}H{sub 4} transitions occurred. The photoacoustic data provided evidence of the energy transfer that resulted in heat generation in the sample, confirming the observations provided by the luminescence data. The energy transfer mechanisms that are involved in the Pr{sup 3+}:Yb{sup 3+} co-doped LSCAS glasses are discussed. -- Highlights: • We report on spectroscopic studies and downconversion luminescence in OH{sup −}-free Pr{sup 3+}–Yb{sup 3+} co-doped low-silica calcium aluminosilicate glasses. • The dependencies of downconversion properties and photoacoustic signals on the Yb{sub 2}O{sub 3} concentration provided new insights on energy transfer Pr{sup 3+}→Yb{sup 3+}. • The results confirmed the occurrence of downconversion, followed by a back-energy transfer mechanism Yb{sup 3+}→Pr{sup 3+} and multiphonon relaxations in Pr{sup 3+}.

  2. Multifunctional nanomesoporous materials with upconversion (in vivo) and downconversion (in vitro) luminescence imaging based on mesoporous capping UCNPs and linking lanthanide complexes

    Science.gov (United States)

    Sun, Lining; Ge, Xiaoqian; Liu, Jinliang; Qiu, Yannan; Wei, Zuwu; Tian, Bo; Shi, Liyi

    2014-10-01

    A series of new multifunctional nanomesoporous materials based on upconversion nanophosphors NaYF4:Yb,Tm@NaGdF4 (UCNPs) and lanthanide complexes were designed and synthesized through mesoporous capping UCNPs nanophosphors and linking lanthanide (Ln) complexes. The obtained UCNPs@mSiO2-Ln(dbm)4 (Ln = Eu, Sm, Er, Nd, Yb) materials can achieve downconversion and upconversion luminescence to show multicolor emission (covering the spectral region from 450 nm to 1700 nm) under visible-light excitation and 980 nm excitation, respectively. In addition, low cytotoxicity and good biocompatibility was found as determined by methyl thiazolyl tetrazolium assay, and the nanomesoporous materials were successfully applied to cell imaging in vitro based on Eu3+ luminescence (under 405 nm excitation) and small animal imaging based on Tm3+ luminescence (under 980 nm excitation). The doped Gd3+ ion endows the nanomesoporous materials UCNPs@mSiO2-Ln(dbm)4 with effective T1 signal enhancement, which affords them as potential magnetic resonance imaging (MRI) contrast agents. Therefore, our results may provide more exciting opportunities for multimodal bioimaging and multifunctional applications.A series of new multifunctional nanomesoporous materials based on upconversion nanophosphors NaYF4:Yb,Tm@NaGdF4 (UCNPs) and lanthanide complexes were designed and synthesized through mesoporous capping UCNPs nanophosphors and linking lanthanide (Ln) complexes. The obtained UCNPs@mSiO2-Ln(dbm)4 (Ln = Eu, Sm, Er, Nd, Yb) materials can achieve downconversion and upconversion luminescence to show multicolor emission (covering the spectral region from 450 nm to 1700 nm) under visible-light excitation and 980 nm excitation, respectively. In addition, low cytotoxicity and good biocompatibility was found as determined by methyl thiazolyl tetrazolium assay, and the nanomesoporous materials were successfully applied to cell imaging in vitro based on Eu3+ luminescence (under 405 nm excitation) and small

  3. Up- and Downconversion Luminescence Properties of Nd3+ Ions Doped in Bi2O3–BaO–B2O3 Glass System

    Directory of Open Access Journals (Sweden)

    R. Ruamnikhom

    2014-01-01

    Full Text Available Physical, optical, and luminescence properties of Nd3+ ions in bismuth barium borate glass system were studied. The glasses prepared by a melt quenching method were doped at various Nd2O3 concentrations in compositions (40-xB2O3 : 40Bi2O3 : 20BaO : xNd2O3 (where x = 0.00, 0.50, 1.00, 1.50, 2.00, and 2.50 in mol%. Luminescence properties of the glasses were studied under two excitations of 585 and 750 nm for downconversion. From both excitations, the results show emission bands in NIR region corresponding to the transitions between 4F3/2 → 4I9/2 (900 nm, 4F3/2 → 4I11/2 (1,060 nm, and 4F3/2 → 4I13/2 (1,345 nm. The luminescence intensity obtained with 585 nm excitation was stronger than 750 nm, with the strongest NIR emission at 1,060 nm. The upconversion emission spectrum exhibits strong fluorescence bands in the UV region at 394 nm (λex=591 nm. The processes are associated with excited state absorption (ESA from 4F3/2 level to 4D3/2 level and it is the radiative decay from the 4D3/2 to ground levels (4D3/2 → 4I13/2 which are responsible for the emission at 394 nm.

  4. Tunable ultraviolet/visible to near-infrared down-conversion luminescence in the Er3+, Yb3+ co-doped (Y0.88La0.09Zr0.03)2O3 transparent ceramics

    Science.gov (United States)

    Hu, Yue; Shahid, Muhammad; Pan, Wei

    2017-10-01

    Herein, we report an efficient ultraviolet/visible to near-infrared (NIR) down-conversion luminescence phenomenon in transparent Er3+, Yb3+ co-doped (Y0.88La0.09Zr0.03)2O3 ceramics. Almost fully densified (Y0.88La0.09Zr0.03)2O3 transparent ceramic has been prepared by vacuum sintering at 1800 °C with different contents of Er3+ and Yb3+ elements. The intensity ratio of Yb3+: 2F5/2 → 2F7/2 emission (∼1000 nm) to the Er3+: 4I13/2 → 4I15/2 emission (∼1550 nm) has been tuned by adjusting the excitation wavelength. Phonon-assist quantum cutting from the 4G11/2 level of Er3+ with two energy transfer (ET) processes to Yb3+ has been determined, which enhances the Yb3+ emission around the wavelength of 1000 nm. It is found that when one photon around 379 nm is absorbed, two photons around 1000 nm will be emitted, and hence the quantum efficiency is estimated to be ∼182% in this transparent ceramics. The mechanism of the visible to near-infrared (NIR) down-conversion luminescence in the Er3+, Yb3+ co-doped (Y0.88La0.09Zr0.03)2O3 ceramics has been discussed.

  5. 下转换发光粉Y2O3/Sm3+在染料敏化太阳能电池中的应用%The Application of Down-conversion Luminescent powder Y2O3/Sm3+ in Dye-sensitized Solar Cells

    Institute of Scientific and Technical Information of China (English)

    王江丽; 林建明; 吴季怀; 兰章; 范乐庆; 黄韵防; 唐子颖

    2011-01-01

    Y2O3/Sm3+ down-conversion luminescent powder was synthesized by a method of precipitation,its structure was characterized by X-ray diffraction. Also, its excitation and emission spectra were presented. Owing to the character of down-conversion, Y2O3/Sm3+ down-conversion luminucent powder was introduced into TiO2 film in dye-sensitized solar cell (DSSC). As a luminescence medium, Y2O3/Sm3+ down-conversion luminescent improves the light harvesting via a conversion luminescence process and increases the photocurrent and the photovoltage. When the TiO2 electrode was doped by 3% Y2O3/Sm3+ ,the cell light-to-electric conversion efficiency was improved from 5. 049% to 5. 940%.%采用沉淀法制备了Y2O3/Sm3+下转换发光粉,利用x射线衍射、荧光光谱对其进行了表征,并利用该发光粉具有下转换发光的特点将其应用于染料敏化太阳能电池(DSSC).结果表明,Y2O3/Sm3+下转换发光粉可以增加电池对太阳光的吸收范围,提高电池的光电流和光电压.研究了掺杂量对电池性能的影响,当掺杂量为3%时,光电转换效率从5.049%提高到5.94%,表明了其是一种有效提高光电转换效率的方法.

  6. Influence of Er3+/Yb3+ concentration ratio on the down-conversion and up-conversion luminescence and lifetime in GdVO4:Er3+/Yb3+ microcrystals

    Directory of Open Access Journals (Sweden)

    Gavrilović T.V.

    2015-01-01

    Full Text Available In this paper, we studied the effects of Er3+/Yb3+ concentration ratio on structural, morphological and luminescence properties of GdVO4:Er3+/Yb3+ green phosphors prepared by a high-temperature solid state method. The samples with different concentrations (between 0.5 to 2 mol% of dopant Er3+ emitting ions and different concentrations (between 5 to 20 mol% of sensitizer ions (Yb3+ were studied. The phosphors were characterized by the X-ray diffraction (XRD, scanning electron microscopy (SEM and photoluminescence spectroscopy. For all samples, XRD diffraction patterns confirmed a formation of a pure GdVO4 phase, while the SEM showed that the materials are comprised of chunks of deformed particles with an average diameter ranging from approximately 2 μm to 8 μm. Both, down-conversion and up-conversion emission spectra of GdVO4:Er3+/Yb3+ samples, under near UV and IR excitations, exhibit two strong emission bands in the green spectral region at 525 nm and 552 nm wavelengths corresponding to 2H11/2 →4I15/2 and 4S3/2 → 4I15/2 electronic transitions of Er3+ ions. The intensity of the green emission was changed by changing the Er3+/Yb3+ concentration ratio. This dual-mode luminescence makes these materials ideal as green phosphors for a wide variety of applications in the fields of bioanalysis and biomedical. [Projekat Ministarstva nauke Republike Srbije, br. 45020 i br. 172056

  7. Quantum frequency downconversion experiment

    CERN Document Server

    Takesue, Hiroki

    2010-01-01

    We report the first quantum frequency downconversion experiment. Using the difference frequency generation process in a periodically poled lithium niobate waveguide, we successfully observed the phase-preserved frequency downconversion of a coherent pulse train with an average photon number per pulse of $<$1, from the 0.7-$\\mu$m visible wavelength band to the 1.3-$\\mu$m telecom band. We expect this technology to become an important tool for flexible photonic quantum networking, including the realization of quantum repeater systems over optical fiber using atom-photon entanglement sources for the visible wavelength bands.

  8. Co-operatives and Normative Control

    DEFF Research Database (Denmark)

    Bregn, Kirsten; Jagd, Søren

    1992-01-01

    This paper explores the conditions for applying normative control in co-operatives. For normative control to be effective two conditions are found particularly important: Individuals must be morally involved and the organization must have a system of making it possible to link common norms...... and individual action. If these conditions are not fulfilled, as may be the case in many co-operatives, normative control cannot be expected to work. The problems of normative control in co-operatives may then not be caused by the use of normative control as such, but may instead be a problem of securing...... the conditions necessary for normative control. This is illustrated by a case study of control in a Danish producers co-operative. The analysis of the case study leads to the hypothesis of a paradox of normative control in co-operatives: The need of information tends to be greater in co-operatives comparet...

  9. List of co-operating Herbaria

    NARCIS (Netherlands)

    NN,

    1949-01-01

    As was pointed out in the first instalment, the management of Flora Malesiana acknowledge collaborating and co-operating institutions; for this purpose a distinction was made between collaborators and co-operators. The former take an active part in the composition of the work (by revising certain fa

  10. Making Co-Operative Ideas Work

    Science.gov (United States)

    Arnold, Phil

    2013-01-01

    Reddish Vale Technology College was the first co-operative trust in England. The democratic and co-operative nature of the experiment mean that students have gained a greater voice in the organisation of the school. As a result, new social enterprises, environmental interventions, connections with the community and with the wider co-operative…

  11. International co-operation in astronomy

    NARCIS (Netherlands)

    Minnaert, Marcel Gilles Jozef

    1955-01-01

    Scientific co-operation between the nations is found already in Antiquity and the Middle Ages and has proved a strong stimulus to the development of astronomy. Different forms of modern international co-operation in astronomy may be distinguished: (1) co-ordinated observations at widely separated st

  12. Agricultural Productivity, Co-Operatives and Organisational ...

    African Journals Online (AJOL)

    Agricultural Productivity, Co-Operatives and Organisational Innovations: A Case of ... productivity and increase farmers' income by bringing financial services closer. ... of Kimuli Agricultural Marketing Co-operative Society (AMCOS) and Muungano ... Also, coffee farmers were able to innovate a new structure for harmonising ...

  13. The Shanghai Co-operation Organisation

    DEFF Research Database (Denmark)

    Hansen, Flemming Splidsboel

    New regional organisations are always interesting to follow as they will tell us more about the things that make or break this type of co-operation. Originally established as “The Shanghai Five” in 1996, The Shanghai Co-operation Organisation (SCO) has been successful at reducing tension between ...

  14. Co-operatives and Normative Control

    DEFF Research Database (Denmark)

    Bregn, Kirsten; Jagd, Søren

    1992-01-01

    This paper explores the conditions for applying normative control in co-operatives. For normative control to be effective two conditions are found particularly important: Individuals must be morally involved and the organization must have a system of making it possible to link common norms...... to other organizations because of the special features of co-operative organizations: use of normative control, democratic decision-making, and decentralized organizational structure. On the other hand, however, there may be strong barriers in co-operatives against creating a sufficient information system....

  15. Experiments with calibrated digital sideband separating downconversion

    CERN Document Server

    Morgan, Matthew A

    2010-01-01

    This article reports on the first step in a focused program to re-optimize radio astronomy receiver architecture to better take advantage of the latest advancements in commercial digital technology. Specifically, an L-Band sideband-separating downconverter has been built using a combination of careful (but ultimately very simple) analog design and digital signal processing to achieve wideband downconversion of an RFI-rich frequency spectrum to baseband in a single mixing step, with a fixed-frequency Local Oscillator and stable sideband isolation exceeding 50 dB over a 12 degree C temperature range.

  16. Transnational Research Co-operation: Opportunities and Challenges for transnational research co-operation

    DEFF Research Database (Denmark)

    participated this workpackage. The objectives of this workpackage relates to the facilitation of transnational research co-operation among Science Shops and development of concepts and procedures for co-operation between the International Science Shop Network Living Knowledge’s members, on community based...... for transnational co-operation like: an investigation/project concerning the driving forces behind urban development,or a co-operation in the field of wastewater reuse and minimization of wastewater loads and discharge, or a service page (internet) to search for potential partners. The governmental institutions...... of pollution • Dioxin leakage from incinerators • Nuclear power • Transport • Energy and climate • GMO • Environmental conditions in communities • Cleaner production • Environmental impact of human activities • Common international Science Shop database • Comparative studies of Science Shop projects...

  17. Laser-induced down-conversion parameters of singly and doubly doped ZnS phosphors

    Indian Academy of Sciences (India)

    H S Bhatti; Rajesh Sharma; N K Verma

    2005-09-01

    Singly and doubly doped ZnS phosphors have been synthesized using flux method. Laser-induced photoluminescence has been observed in ZnS-doped phosphors when these were excited by the pulsed UV N2 laser radiation. Due to down-conversion phenomenon, fast phosphorescence emission in the visible region is recorded in milliseconds time domain for ZnS:Mn while in the case of ZnS:Mn:killer (Fe, Co and Ni) the lifetime reduces to microseconds time domain. Experimentally observed luminescent emission parameters of excited states such as, lifetimes, trap-depth values and decay constants have been reported here at room temperature. The high efficiency and fast recombination times observed in doped ZnS phosphors make these materials very attractive for optoelectronic applications.

  18. Co-Operation: The Antidote to Isolated Misery

    Science.gov (United States)

    Jones, Sarah

    2013-01-01

    This is a case study demonstrating the impact the co-operative movement has had on one co-operative school in south-west England. Lipson Co-operative Academy in Plymouth was one of the first schools to convert to become a co-operative school in 2009. The article has been co-written by members of the Academy and focuses on three transformational…

  19. International solar energy research co-operation

    Energy Technology Data Exchange (ETDEWEB)

    Lund, P.; Peippo, K.; Konttinen, P. [Helsinki Univ. of Technology, Otaniemi (Finland). Advanced Energy Systems

    1998-10-01

    Finland has participated in several IEA activities during 1996-97. HUT coordinates the activities, but practical participation in collaborative actions take place both in industrial companies and research organisations. Neste Ltd has directly participated in several tasks and information of results has been disseminated more widely to Finnish industries and organisations. Co-operation projects covered here are: (1) IEA Photovoltaic Power Systems Task 1 `Information dissemination`, (2) IEA Photovoltaic Power Systems Task 3 `Use of Photovoltaic systems in Stand Alone and Island Applications`, (3) IEA Photovoltaic Power Systems Task 7 `Photovoltaics in built environment`, (4) IEA Solar Heating and Cooling Program Task 16 `Photovoltaics in buildings` and (5) IEA Working Group `Materials in Solar Thermal Collectors`

  20. Luminescence Instrumentation

    DEFF Research Database (Denmark)

    Jain, Mayank; Bøtter-Jensen, Lars

    2014-01-01

    This chapter gives an introduction to instrumentation for stimulated luminescence studies, with special focus on luminescence dating using the natural dosimeters, quartz and feldspars. The chapter covers basic concepts in luminescence detection, and thermal and optical stimulation, and reference...

  1. Luminescence in germania-silica fibers in a 1-2 μm region

    Science.gov (United States)

    Borshchevskaia, N. A.; Katamadze, K. G.; Kulik, S. P.; Klyamkin, S. N.; Chuvikov, S. V.; Sysolyatin, A. A.; Tsvetkov, S. V.; Fedorov, M. V.

    2017-08-01

    We analyze the origins of the luminescence in germania-silica fibers with high germanium concentration (about 30 mol. % GeO2) in the region 1-2 {\\mu}m with a laser pump at the wavelength 532 nm. We show that such fibers demonstrate the high level of luminescence which unlikely allows the observation of photon triplets, generated in a third-order spontaneous parametric down-conversion process in such fibers. The only efficient approach to the luminescence reduction is the hydrogen saturation of fiber samples, however, even in this case the level of residual luminescence is still too high for three-photon registration.

  2. Romanian-Danish Environmental Co-operation. Co-operation development 1993-1998

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-08-01

    The Danish Ministry of Environment and Energy has, since 1991, through the Danish Environmental Support Fund, contributed towards protecting the environment and nature in Central and Eastern European countries and has helped to limit regional as well as global pollution. The Romanian Ministry of Waters, Forests and Environmental Protection and the Danish Ministry of Environment and Energy initiated the co-operation in 1993 and an official Agreement was signed in 1994. This publication describes the co-operation between the two countries in the field of the environment in the hope that this will give both the general public of Romania and the international community a better understanding of the work being accomplished. It also gives an overview of the 19 projects developed within this framework, which has a total Danish grant of DKK 77.9 million. (au)

  3. Improving livestock production through co-operative societies

    Directory of Open Access Journals (Sweden)

    M.A. Umaru

    2013-03-01

    Full Text Available This paper reviews the positive role livestock Co-operatives can play in enhancing animal production. Livestock Co-operative Societies such as those for Artificial insemination, Dairy, Beef and Poultry production have been discussed. The paper also dwells on the benefits derivable from such organisations. The practice of Co-operative Societies in livestock production has been applied by different countries in different livestock sub-sectors. This paper concludes that establishing such Co-operatives will significantly improve livestock production in Nigeria.

  4. Co-operative groups in their environments : a population-ecological model for co-operative membership and performance

    OpenAIRE

    Lasowski, Ophir

    2010-01-01

    The aim of this work is to develop an alternative evolutionary approach to assessing the performance of co-operative organizations. The focus of investigation is turned to the co-operative organization as a group of members in a market environment containing non-members. Significant unique features of the co-operative organization is illustrated at first. After reviewing historical aspects of evolution theories and their positioning in biology, economic and social sciences, alternative notion...

  5. Success parameters for housing co-operatives in South Africa

    Directory of Open Access Journals (Sweden)

    Jimoh Richard

    2012-12-01

    Full Text Available The roles of the various governments have been the driving force of the housing co-operatives in those countries due to the tremendous support received. The implication is that the housing co-operatives in any country cannot do it alone without the support of government in areas such as having legislation and policies, providing support services and embarking on regular education and training. The need to explore the housing co-operatives in South Africa with a view to determine the successes recorded over the years becomes imperative in order to advance strategies that will ensure virile and sustainable housing co-operatives. Results revealed that a lack of understanding exists as a result of inadequate information among government officials responsible for housing delivery and the public in the application of co-operative housing as a delivery approach. Also, inadequate training of co-operative members in leadership positions lead to a lack of administrative and management capabilities in the processes and operations of housing co-operatives. A pragmatic approach should be adopted so that legislation and policies that are beneficial to the housing co-operatives be enacted.

  6. Absolute measurement of detector quantum efficiency using parametric downconversion.

    Science.gov (United States)

    Rarity, J G; Ridley, K D; Tapster, P R

    1987-11-01

    We show that a parametric downconversion crystal emitting angle resolved coincident photon pairs can be used to measure the absolute quantum efficiency of a photon counting detection system. We have measured the quantum efficiency of a silicon avalanche photodiode, operated in Geiger mode, as a function of operating voltage and compare this to results obtained using a conventional method.

  7. Efficient fiber coupling of down-conversion photon pairs

    CERN Document Server

    Dragan, A

    2004-01-01

    We develop and apply an effective analytic theory of a non-collinear, broadband type-I parametric down-conversion to study a coupling efficiency of the generated photon pairs into single mode optical fibers. We derive conditions necessary for highly efficient coupling for single and double type-I crystal producing polarization entangled states of light. We compare the obtained approximate analytic expressions with the exact numerical solutions and discuss the results for a case of BBO crystals.

  8. Revisiting non-degenerate parametric down-conversion

    Indian Academy of Sciences (India)

    Joseph Akeyo Omolo

    2008-12-01

    The quantum dynamics of a two-mode non-resonant parametric down-conversion process is studied by recasting the time evolution equations for the basic operators in an equivalent spin equation form with simpler exact solutions for a pump field with harmonic time dependence. Expectation values of suitable operators for studying important features such as squeezing and quantum revivals are presented in simple forms.

  9. White Light Emission Through Downconversion of Terbium and Europium Doped CeF3 Nanophosphors.

    Science.gov (United States)

    Varun, S; Kalra, Mohit; Gandhi, Mayuri

    2015-09-01

    CeF3 nanophosphors have been extensively investigated in recent years for lighting and numerous bio-applications. Downconversion emissions in CeF3:Eu(3+)/Tb(3+) phosphors were studied with the objective of attaining a white light emitting composition, by means of a simple co-precipitation method. The material was characterized by X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM), Fourier Transform Infrared Spectroscopy (FT-IR) and Photoluminescence (PL). Uniformly distributed nanoparticles were obtained with an average particle size range of 8-10 nm. Various studies were undertook utilizing different doping concentrations and respective fluorescence studies were carried out to optimize dopant concentrations while achieving maximum luminescence intensity. From PL results, it was observed that the efficient energy transfers from the donor to the acceptor ions. Different concentrations of Tb(3+), Eu(3+) were doped in order to achieve a white light emitting phosphor for UV-based Light Emitting Diodes (LEDs). The nanoparticles showed characteristic emission of respective dopants (Eu(3+), Tb(3+)) when excited at the 4f → 5d transition of Ce(3+). The chromaticity coordinates for CeF3 doped with Eu(3+) and Tb(3+) were calculated and an emission very close to white light was observed.

  10. Upcrowding energy co-operatives - Evaluating the potential of crowdfunding for business model innovation of energy co-operatives.

    Science.gov (United States)

    Dilger, Mathias Georg; Jovanović, Tanja; Voigt, Kai-Ingo

    2017-08-01

    Practice and theory have proven the relevance of energy co-operatives for civic participation in the energy turnaround. However, due to a still low awareness and changing regulation, there seems an unexploited potential of utilizing the legal form 'co-operative' in this context. The aim of this study is therefore to investigate the crowdfunding implementation in the business model of energy co-operatives in order to cope with the mentioned challenges. Based on a theoretical framework, we derive a Business Model Innovation (BMI) through crowdfunding including synergies and differences. A qualitative study design, particularly a multiple-case study of energy co-operatives, was chosen to prove the BMI and to reveal barriers. The results show that although most co-operatives are not familiar with crowdfunding, there is strong potential in opening up predominantly local structures to a broader group of members. Building on this, equity-based crowdfunding is revealed to be suitable for energy co-operatives as BMI and to accompany other challenges in the same way. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. 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.

  12. China and CERN renew their Co-operation Agreement

    CERN Multimedia

    2004-01-01

    Dr. Liu Yanhua, Chinese Vice Minister of Science and Technology, and Dr. Robert Aymar, Director-General of CERN, sign a new Co-operation Agreement between the Government of the People's Republic of China and CERN. During his visit to CERN on 17 February, Liu Yanhua, Vice Minister of Science and Technology of the People's Republic of China, signed a new Co-operation Agreement with the Laboratory. The Agreement, which is valid for a period of five years and renewable, lays down the framework for the development of scientific and technological co-operation between CERN and China. This includes China's participation, as a non-Member State, in CERN's research projects as well as its main programmes. Robert Aymar and Liu Yanhua underlined that this Agreement will provide an excellent framework for close co-operation on the LHC Programme and Grid and accelerator technologies. Scientific co-operation between China and CERN is nothing new, as Chinese physicists already took part in the LEP experiments. Today, CERN's C...

  13. New co-operation agreement between CERN and JINR

    CERN Multimedia

    CERN Bulletin

    2010-01-01

    CERN Director-General Rolf Heuer (left) and JINR Director Alexei Sissakian (right). On Thursday 28 January, CERN Director-General Rolf Heuer and JINR Director Alexei Sissakian signed a new enlarged co-operation agreement to continue and enhance the scientific and technical co-operation of the two institutes in the field of high-energy physics. CERN and JINR have a long and successful history of collaboration extending back to the earliest days of their existence. The first informal meeting on international co-operation in the field of high-energy accelerators took place at CERN in 1959. It was attended by senior scientists from the United States, the USSR (including JINR) and CERN. Both JINR and CERN have played the role of a bridge between East and West for decades, contributing to the development of international scientific co-operation. In 1992 JINR signed a co-operation agreement with CERN that included an important number of protocols covering JINR’s participation in the construction of th...

  14. Co-operativity in a nanocrystalline solid-state transition

    Science.gov (United States)

    White, Sarah L.; Smith, Jeremy G.; Behl, Mayank; Jain, Prashant K.

    2013-12-01

    Co-operativity is a remarkable phenomenon mostly seen in biology, where initial reaction events significantly alter the propensity of subsequent reaction events, giving rise to a nonlinear tightly regulated synergistic response. Here we have found unique evidence of atomic level co-operativity in an inorganic material. A thousand-atom nanocrystal (NC) of the inorganic solid cadmium selenide exhibits strong positive co-operativity in its reaction with copper ions. A NC doped with a few copper impurities becomes highly prone to be doped even further, driving an abrupt transition of the entire NC to the copper selenide phase, as manifested by a strongly sigmoidal response in optical spectroscopy and electron diffraction measurements. The examples presented here suggest that cooperative phenomena may have an important role in the solid state, especially in the nucleation of new chemical phases, crystal growth, and other materials’ transformations.

  15. Co-operativity in a nanocrystalline solid-state transition.

    Science.gov (United States)

    White, Sarah L; Smith, Jeremy G; Behl, Mayank; Jain, Prashant K

    2013-01-01

    Co-operativity is a remarkable phenomenon mostly seen in biology, where initial reaction events significantly alter the propensity of subsequent reaction events, giving rise to a nonlinear tightly regulated synergistic response. Here we have found unique evidence of atomic level co-operativity in an inorganic material. A thousand-atom nanocrystal (NC) of the inorganic solid cadmium selenide exhibits strong positive co-operativity in its reaction with copper ions. A NC doped with a few copper impurities becomes highly prone to be doped even further, driving an abrupt transition of the entire NC to the copper selenide phase, as manifested by a strongly sigmoidal response in optical spectroscopy and electron diffraction measurements. The examples presented here suggest that cooperative phenomena may have an important role in the solid state, especially in the nucleation of new chemical phases, crystal growth, and other materials' transformations.

  16. Cyberethics and co-operation in the information society.

    Science.gov (United States)

    Fuchs, Christian; Bichler, Robert M; Raffl, Celina

    2009-12-01

    The task of this paper is to ground the notion of cyberethics of co-operation. The evolution of modern society has resulted in a shift from industrial society towards informational capitalism. This transformation is a multidimensional shift that affects all aspects of society. Hence also the ethical system of society is penetrated by the emergence of the knowledge society and ethical guidelines for the information age are needed. Ethical issues and conflicts in the knowledge society are connected to topics of ecological and social sustainability. For information ethics and cyberethics, the sustainable design of society, social, and socio-technological systems is important. In this context the notions of sustainability and co-operation are discussed. Based on these categories, the approach of cyberethics of co-operation can be theoretically grounded.

  17. Photonic downconversion for coherent phase-modulated radio-over-fiber links using free-running local oscillator

    DEFF Research Database (Denmark)

    Caballero Jambrina, Antonio; Zibar, Darko; Schäffer, Christian G.

    2011-01-01

    A digital coherent receiver employing photonic downconversion is presented and experimentally demonstrated for phase-modulated radio-over-fiber optical links. Photonic downconversion adds additional advantages to optical phase modulated links by allowing demodulation of signals with RF carrier...

  18. SMEs and their co-operation with academia.

    Science.gov (United States)

    Antoine, Jean Michel; Strömqvist, Mats

    2005-01-01

    Co-operation between SMEs and Academia can be a win-win situation when each partner understands the constraints of the other. SMEs are often leaders in innovation; therefore more ready to share interest in research. They are flexible and dynamic. They need a short feed-back to sustain their co-operation. Academia is often more long-term oriented and more question- than answer-oriented. A code of conduct can ease the relationship because it can anticipate the potential problems.

  19. Experimental preparation of Werner state via spontaneous parametric down-conversion

    CERN Document Server

    Zhang, Y S; Li, C F; Guo, G C; Zhang, Yong-Sheng; Huang, Yun-Feng; Li, Chuan-Feng; Guo, Guang-Can

    2002-01-01

    We present an experiment of preparing Werner state via spontaneous parametric down-conversion and controlled decoherence of photons in this paper. In this experiment two independent BBO (beta-barium borate) crystals are used to produce down-conversion light beams, which are mixed to prepare Werner state.

  20. Modal spectrum in spontaneous parametric down-conversion with noncollinear phase matching

    CSIR Research Space (South Africa)

    Zhang, Y

    2014-06-01

    Full Text Available We investigate the effect of the down-conversion angle between the signal and idler beams in spontaneous parametric down-conversion on the bandwidth of the modal spectrum (Schmidt number) of the down-converted quantum state. For this purpose, we...

  1. Energy transfer mechanism for downconversion in the (Pr3+, Yb3+) couple

    NARCIS (Netherlands)

    Van Wijngaarden, J.T.; Scheidelaar, S.; Vlugt, T.J.H.; Reid, M.F.; Meijerink, A.

    2010-01-01

    Downconversion of one visible photon into two infrared photons has been reported for the lanthanide ion couple (Pr3+, Yb3+) in a variety of host lattices. The mechanism responsible for downconversion is controversial and has been reported to be either a two-step energy transfer process (via two firs

  2. Military co-operation with South Caucasus countries / Rafal Seniuch

    Index Scriptorium Estoniae

    Seniuch, Rafal

    2003-01-01

    Ettekanne Poola ja Lõuna-Kaukaasia vabariikide vahelisest sõjalis-poliitilisest koostööst 22.-23. septembrini 2003 Vilniuses toimunud seminaril "South Caucasus: making the best use of external assistance for stability building and for co-operation with NATO"

  3. Aid Distribution and Co-operation in Unequal Communities

    NARCIS (Netherlands)

    Exelle, D' B.; Berg, van den M.M.

    2012-01-01

    We study the influence of economic inequality on co-operation and aid distribution in community-based development schemes. For this, we organized a field experiment in which community members contributed to a collective effort to attract aid. We find that devolving aid distribution to community repr

  4. Military co-operation with South Caucasus countries / Rafal Seniuch

    Index Scriptorium Estoniae

    Seniuch, Rafal

    2003-01-01

    Ettekanne Poola ja Lõuna-Kaukaasia vabariikide vahelisest sõjalis-poliitilisest koostööst 22.-23. septembrini 2003 Vilniuses toimunud seminaril "South Caucasus: making the best use of external assistance for stability building and for co-operation with NATO"

  5. International technical co-operation for a safer world

    Energy Technology Data Exchange (ETDEWEB)

    Velez Ocon, C. (International Atomic Energy Agency, Vienna, Austria)

    1982-01-01

    Among the various technologies available today, those related to energy and energy production are of paramount importance since, without energy, all programmes and models for development, regardless of their scope or soundness, represent only exercises in wishful thinking. Efforts to promote international technical co-operation in the field of energy seldom make headlines in the world. Typically, such co-operation - in which the provision of assistance plays a fundamental role - proceeds slowly, and its results only become manifest many years later. It is, however, an indispensable part of the global effort to narrow the technological gap. For the International Atomic Energy Agency, the furtherance of technical co-operation in the nuclear field is a primary objective, and this role is clearly defined in the organization's statute. The Agency contributes to the transfer of nuclear technology in many ways. It plays the important role of an intermediary between Member States in the transfer of experience, information, materials and equipment. The Agency's activity in the fields of technical co-operation and technical assistance is described in this article.

  6. Impact of Co-Operative Learning Strategies in English

    Science.gov (United States)

    Singaravelu, G.

    2010-01-01

    The study illuminates the effectiveness of Co-operative Learning Strategies in learning English Grammar for the learners at secondary level. Cooperative Learning is particularly beneficial for any student learning as a second language. It promotes peer interaction, which helps the development of language and the learning of concepts with content.…

  7. Electrification co-operatives bring new light to rural Tanzania

    Energy Technology Data Exchange (ETDEWEB)

    Ilskog, Elisabeth E-mail: elisabeth.ilskog@af.se; Kjellstroem, B. E-mail: bjorn@kjellstrom.se; Gullberg, Monica E-mail: monica.gullberg@af.se; Katyega, Maneno E-mail: mkatyega@tanesco.co.tz; Chambala, William E-mail: uecco@bushlink.co.tz

    2005-07-01

    One possibility to accelerate the progress of rural electrification in developing countries could be to form independent electrification co-operatives that are allowed to generate and distribute electric power and set their own tariffs. This approach has been successfully tried in the village Urambo, located about 80 km west of Tabora in Tanzania. The co-operative was formed in 1993 and started regular operation in 1994 with 67 consumers. The co-operative received initial financial support for rehabilitation of a diesel power plant and some other investments. The national utility TANESCO has provided technical support and training for operators and an accountant. Despite a tariff more than 15 times higher than in the nearby town Tabora that is served by TANESCO, the number of consumers in Urambo has been growing and reached 241 in October 2002. About 70% of the supplied electricity in 2002 was used by households, 15% in businesses, 12% in institutions and public buildings and approximately 3% for street lighting. The reliability of the supply has improved from 80% in 1994, to 97% during 2002. The experiences must be considered as very promising. Several more electrification co-operatives have been formed in Tanzania and are looking for financing for the necessary initial investments.

  8. On-the-fly decoding luminescence lifetimes in the microsecond region for lanthanide-encoded suspension arrays

    Science.gov (United States)

    Lu, Yiqing; Lu, Jie; Zhao, Jiangbo; Cusido, Janet; Raymo, Françisco M.; Yuan, Jingli; Yang, Sean; Leif, Robert C.; Huo, Yujing; Piper, James A.; Paul Robinson, J.; Goldys, Ewa M.; Jin, Dayong

    2014-05-01

    Significant multiplexing capacity of optical time-domain coding has been recently demonstrated by tuning luminescence lifetimes of the upconversion nanoparticles called ‘τ-Dots’. It provides a large dynamic range of lifetimes from microseconds to milliseconds, which allows creating large libraries of nanotags/microcarriers. However, a robust approach is required to rapidly and accurately measure the luminescence lifetimes from the relatively slow-decaying signals. Here we show a fast algorithm suitable for the microsecond region with precision closely approaching the theoretical limit and compatible with the rapid scanning cytometry technique. We exploit this approach to further extend optical time-domain multiplexing to the downconversion luminescence, using luminescence microspheres wherein lifetimes are tuned through luminescence resonance energy transfer. We demonstrate real-time discrimination of these microspheres in the rapid scanning cytometry, and apply them to the multiplexed probing of pathogen DNA strands. Our results indicate that tunable luminescence lifetimes have considerable potential in high-throughput analytical sciences.

  9. AN EFFICIENT IMPLEMENTATION ARCHITECTURE FOR WIDE-BAND DIGITAL DOWNCONVERSION

    Institute of Scientific and Technical Information of China (English)

    Gao Zhicheng; Xiao Xianci

    2001-01-01

    The wide-band digital receiving systems require digital downconversion(DDC) with high data rate and short tuning time in order to intercept the narrow-band signals within broad tuning bandwidth. But these requirements can not be met by the commercial DDC. In this paper an efficient implementation architecture is presented. It combines the flexibility of DFT tuning with the efficiency of the polyphase filter bank decomposition. By first decimating the data prior to filtering and mixing, this architecture gives a better solution to the mismatch between the lower hardware speed and high data rate. The computer simulations show the feasibility of this processing architecture.

  10. Spatial antibunching of photons with parametric down-conversion

    CERN Document Server

    Nogueira, W A T; Pádua, S; Monken, C H

    2002-01-01

    The theoretical framework behind a recent experiment by Nogueira et al. [Phys. Rev. Lett. 86, 4009 (2001)] of spatial antibunching in a two-photon state generated by collinear type II parametric down-conversion is presented. The fourth-order quantum correlation function is evaluated and shown to violate the classical Schwarz-type inequality, ensuring that the field does not have a classical analog. We expect these results to be useful in the rapidly growing fields of quantum imaging and quantum information.

  11. Cross-border mergers between agricultural co-operatives -a governance perspective

    DEFF Research Database (Denmark)

    Nilsson, Jerker; Madsen, Ole Øhlenschlæger

    that the driving force behind a crossbordermerger is the top management teams of the co-operatives, and these persons have onlyweak connections to the co-operative societies, and limited knowledge about the socialnetworks within the memberships. These observations imply that there are some challenges tocross......A merger between agricultural co-operatives involves two merger processes - one concerningthe two co-operative business firms and the other concerning the two co-operative societies,i.e., the ownership organisations. These two merger processes are mutually dependent. If amerger involves co-operatives......-border mergers between agricultural co-operatives....

  12. BANKING SYSTEM STABILITY: COMMERCIAL AND CO-OPERATIVE BANKS

    Directory of Open Access Journals (Sweden)

    Dumitru-Cristian OANEA

    2014-04-01

    Full Text Available Commercial banks and co-operative banks are credit institutions, but there are some differences between the main operations proceeded by each of them. Based on these specific characteristics, we want to identify the manner in which financial crisis affected their activity. As we all know, the financial crisis had a major impact in the United States, the “natal” country of the crisis, because great banks such as Lehman Brothers or Merrill Lynch have bankrupted. Even if the Romanian banking system was not affected by such catastrophic situations, surely the financial crisis had a significant impact on it. This topic is worth to be analysed, because we would be able to identify the risk differences between these two types of business: commercial banks versus co-operative banks.

  13. International co-operation in the field of wind energy

    Energy Technology Data Exchange (ETDEWEB)

    Wolff, J. [VTT Energy, Espoo (Finland)

    1998-10-01

    The use of wind energy is expanding rapidly worldwide. At the end of 1996 over 6000 MW was installed and the annual increase has during the last years exceeded 1000 MW. The development is also reaching more and more countries. In order to maintain technical and commercial development international co-operation is needed to secure cost-effectiveness, reliability and safety of the technology. International recommendations, harmonisation and standardisation is promoted by several international organizations like IEA, IEC and the classification organisations

  14. Signal co-operation between integrins and other receptor systems.

    Science.gov (United States)

    Streuli, Charles H; Akhtar, Nasreen

    2009-03-15

    The multicellular nature of metazoans means that all cellular processes need to be tuned by adhesive interactions between cells and their local microenvironment. The spatial organization of cells within tissues requires sophisticated networks of extracellular signals to control their survival and proliferation, movements and positioning, and differentiated function. These cellular characteristics are mediated by multiple inputs from adhesion systems in combination with soluble and developmental signals. In the present review we explore how one class of adhesion receptor, the integrins, co-operate with other types of receptor to control diverse aspects of cell fate. In particular we discuss: (i) how beta3 and beta1 integrins work together with growth factors to control angiogenesis; (ii) how alpha6beta4 integrin co-operates with receptor tyrosine kinases in normal epithelial function and cancer; (iii) the interplay between beta1 integrins and EGF (epidermal growth factor) receptor; (iv) signal integration connecting integrins and cytokine receptors for interleukins, prolactin and interferons; and (v) how integrins and syndecans co-operate in cell migration.

  15. Harmonic entanglement in a degenerate parametric down-conversion

    Energy Technology Data Exchange (ETDEWEB)

    Tesfa, Sintayehu [Physics Department, Addis Ababa University, PO Box 1176, Addis Ababa (Ethiopia)], E-mail: sint_tesfa@yahoo.com

    2008-03-28

    A detailed study of the harmonic entanglement and two-mode squeezing of radiation generated in a degenerate parametric down-conversion process when the cavity is coupled to a two-mode vacuum reservoir is presented. It is found that there is a quadrature entanglement between the harmonically related fundamental and residual pump modes where the superimposed radiation exhibits a higher degree of two-mode squeezing. It turns out that the two-mode squeezing can exist when there is no entanglement, since the correlations leading to these phenomena are essentially different. It is also shown that the more the external pumping radiation is down-converted by the nonlinear crystal, the stronger the entanglement and intensity of the two-mode radiation would be; this condition is not generally true for squeezing.

  16. Unity-Efficiency Parametric Down-Conversion via Amplitude Amplification

    Science.gov (United States)

    Niu, Murphy Yuezhen; Sanders, Barry C.; Wong, Franco N. C.; Shapiro, Jeffrey H.

    2017-03-01

    We propose an optical scheme, employing optical parametric down-converters interlaced with nonlinear sign gates (NSGs), that completely converts an n -photon Fock-state pump to n signal-idler photon pairs when the down-converters' crystal lengths are chosen appropriately. The proof of this assertion relies on amplitude amplification, analogous to that employed in Grover search, applied to the full quantum dynamics of single-mode parametric down-conversion. When we require that all Grover iterations use the same crystal, and account for potential experimental limitations on crystal-length precision, our optimized conversion efficiencies reach unity for 1 ≤n ≤5 , after which they decrease monotonically for n values up to 50, which is the upper limit of our numerical dynamics evaluations. Nevertheless, our conversion efficiencies remain higher than those for a conventional (no NSGs) down-converter.

  17. Multimode Spontaneous Parametric Down-Conversion in the Lossy Medium

    CERN Document Server

    Chrapkiewicz, Radoslaw

    2009-01-01

    We study the process of multimode Spontaneous Parametric Down--Conversion (SPDC) in the lossy, one dimensional waveguide. We propose a description using first order Correlation Functions (CF) in the fluorescence fields, as a very fruitful and easy approach providing us with a complete information about the final multimode state. We formulate the equation of the evolution of the multimode CF along the crystal using four characteristic length scales. We solve it analytically in the one mode case and numerically in the multimode case. We capture simultaneous effects of three wave mixing with ultrashort pump, linear propagation and attenuation, and we are able to divide the evolution into three stages and predict it qualitatively. We find that losses do not destroy the quantum properties of SPDC but stabilize the final state.

  18. Radial modal dependence of the azimuthal spectrum after parametric down-conversion

    CSIR Research Space (South Africa)

    Zhang, Y

    2014-01-01

    Full Text Available The radial degrees of freedom of the biphoton states that are produced in spontaneous parametric down-conversion (SPDC) in the Laguerre-Gaussian (LG) basis are investigated, theoretically and experimentally. We calculated the theoretical azimuthal...

  19. Healthcare technology co-operatives: Innovative about innovation.

    Science.gov (United States)

    Heron, Nicola M; Tindale, Wendy B

    2014-01-01

    The paper provides an introduction to the National Institute for Health Research Devices for Dignity Healthcare Technology Co-operative. Embedded within the NHS, Devices for Dignity identifies areas of unmet clinical need and translates these into research and development projects to develop new medical technologies. It addresses the needs of people living with long-term conditions, helping them to live more dignified and independent lives. Through partnerships with patients, universities, the NHS and industry, Devices for Dignity has developed an innovation methodology for successful medical technology innovation.

  20. Interfacing a quantum dot with a spontaneous parametric down-conversion source

    Science.gov (United States)

    Huber, Tobias; Prilmüller, Maximilian; Sehner, Michael; Solomon, Glenn S.; Predojević, Ana; Weihs, Gregor

    2017-09-01

    Quantum networks require interfacing stationary and flying qubits. These flying qubits are usually nonclassical states of light. Here we consider two of the leading source technologies for nonclassical light, spontaneous parametric down-conversion and single semiconductor quantum dots. Down-conversion delivers high-grade entangled photon pairs, whereas quantum dots excel at producing single photons. We report on an experiment that joins these two technologies and investigates the conditions under which optimal interference between these dissimilar light sources may be achieved.

  1. Photonic Downconversion and Optically Controlled Reconfigurable Antennas in mm-waves Wireless Networks

    DEFF Research Database (Denmark)

    da Costa, I. F.; Rodríguez Páez, Juan Sebastián; Vegas Olmos, Juan José

    2016-01-01

    We report on optically controlled antennas and photonic downconversion for mm-wave wireless communication applications. Experimental results demonstrate a transmission of 1.25 Gb/s using 28 and 38GHz frequency bands......We report on optically controlled antennas and photonic downconversion for mm-wave wireless communication applications. Experimental results demonstrate a transmission of 1.25 Gb/s using 28 and 38GHz frequency bands...

  2. EDITORIAL: Co-operation by Mutual Transfer of Manuscripts

    Science.gov (United States)

    Müller-Krumbhaar, H.

    2002-12-01

    Co-operation among scientifically qualified journals is essential for providing authors with a proper wide audience in the interest of the progress of sciences. The reviewing process of a scientifically qualified paper occasionally comes to the conclusion that the manuscript might be more suitable for a different journal than the one to which it was originally submitted. The author might be inclined to agree to such a transfer of his/her manuscript to a different journal, if the original submission date of the manuscript would be maintained ant the related materials transmitted as well. In order to facilitate this transfer of papers between The European Physical Journal and Europhysics Letters, the Editors-in-Chief of these journals have come to an agreement for the transfer of suitable manuscripts from one journal to another journal that should avoid unnecessary publication delays. Other journals published in Europe may join this co-operation. In case of such an intended transfer of a submitted manuscript, the editor of the journal who has received the manuscript asks the author for his agreement and contacts the editor of the other journal. He sends him the manuscript and related material from the reviewing process. The final decision on the manuscript publication stays the with then editor of the journal to which the manuscript is transferred, who can either make his decision on the basis of the existing reports or ask for complementary reports.

  3. Rhadinovirus host entry by co-operative infection.

    Directory of Open Access Journals (Sweden)

    Clara Lawler

    2015-03-01

    Full Text Available Rhadinoviruses establish chronic infections of clinical and economic importance. Several show respiratory transmission and cause lung pathologies. We used Murid Herpesvirus-4 (MuHV-4 to understand how rhadinovirus lung infection might work. A primary epithelial or B cell infection often is assumed. MuHV-4 targeted instead alveolar macrophages, and their depletion reduced markedly host entry. While host entry was efficient, alveolar macrophages lacked heparan - an important rhadinovirus binding target - and were infected poorly ex vivo. In situ analysis revealed that virions bound initially not to macrophages but to heparan⁺ type 1 alveolar epithelial cells (AECs. Although epithelial cell lines endocytose MuHV-4 readily in vitro, AECs did not. Rather bound virions were acquired by macrophages; epithelial infection occurred only later. Thus, host entry was co-operative - virion binding to epithelial cells licensed macrophage infection, and this in turn licensed AEC infection. An antibody block of epithelial cell binding failed to block host entry: opsonization provided merely another route to macrophages. By contrast an antibody block of membrane fusion was effective. Therefore co-operative infection extended viral tropism beyond the normal paradigm of a target cell infected readily in vitro; and macrophage involvement in host entry required neutralization to act down-stream of cell binding.

  4. Sixteen Years of International Co-operation. The OECD/NEA Co-operative Programme on Decommissioning

    Energy Technology Data Exchange (ETDEWEB)

    Menon, S.; Valencia, L.

    2002-02-25

    The Co-operative Programme on Decommissioning under the administration of the Radioactive Waste Management Committee of the OECD Nuclear Energy Agency (NEA) has recently completed sixteen years of operation. The Programme, which is essentially an information exchange programme between decommissioning projects, came into being in 1985. It has grown from an initial 10 decommissioning projects from 7 countries to 39 projects from 14 countries today. From purely information exchange to start with, the Programme has, in later years, been functioning as a voice for the collective expression of views of the implementers of nuclear decommissioning. During the first sixteen years of the operation of the Co-operative Programme, nuclear decommissioning has grown from local specialist activities within projects to a competitive commercial industry. By the dismantling and release from regulatory control of over a dozen diverse nuclear facilities, the Programme has been able to demonstrate in practice, that nuclear decommissioning can be performed safely both for the workers and the public, and that this can be done at reasonable costs in an environmentally friendly fashion. During the recent years, discussions and work within the Co-operative Programme, specially within some of the Task Groups, have had/are having effects and repercussions not just in the field of nuclear decommissioning, but can possibly affect activities and regulations in other industries. This paper describes how the Programme and its activities and procedures have evolved over the years and indicate the directions of developments in the organization and execution of decommissioning projects. Finally, it gives a brief overview of the achievements of the Cooperative Programme and visualizes future developments in the field of nuclear decommissioning.

  5. The Effectiveness of Structured Co-Operative Teaching and Learning in Greek Primary School Classrooms

    Science.gov (United States)

    Kaldi, Stavroula; Filippatou, Diamanto; Anthopoulou, Barbara

    2014-01-01

    This study focuses upon the effectiveness of structured co-operative group work on primary school students, aged between 8.5 and 9.5 years old, regarding their content knowledge, attitudes towards co-operative group work, experiential learning and open-ended curriculum as well as students' social and learning behaviour during co-operative group…

  6. The Effectiveness of Structured Co-Operative Teaching and Learning in Greek Primary School Classrooms

    Science.gov (United States)

    Kaldi, Stavroula; Filippatou, Diamanto; Anthopoulou, Barbara

    2014-01-01

    This study focuses upon the effectiveness of structured co-operative group work on primary school students, aged between 8.5 and 9.5 years old, regarding their content knowledge, attitudes towards co-operative group work, experiential learning and open-ended curriculum as well as students' social and learning behaviour during co-operative group…

  7. The Architecture of Co-operation: A Project for organizing collective creativity

    NARCIS (Netherlands)

    Borra, B.

    2014-01-01

    The Architecture of Co-operation investigates the relationship between the collective subject and urban form through co-operation as means of production. The point is how individuals can organize co-operation today for the city as a project and what could be the role of architects into this process.

  8. Protocol to co-operation agreement with Iran

    CERN Document Server

    2001-01-01

    A Co-operation Agreement between CERN and Iran will be signed in the coming weeks within the framework of the decisions taken by the Committee of Council and Council in June 1989. In view of implementing this Agreement, a Protocol between CERN and the International Scientific Meetings Office of the Ministry of Science of the Islamic Republic of Iran has been drawn up. It concerns the participation of scientific Institutions of Iran in the CMS Collaboration where CERN is acting on behalf of this Collaboration. This Protocol incorporates the agreement between CMS and ISMO on the Iranese contribution. It does not involve any financial commitment for CERN. The Protocol mainly addresses the status of the Iranese scientists at CERN, the supply by ISMO of the support tables for CMS, as well as the usual provisions concerning delivery and customs, guarantees, responsibilities, intellectual property and disputes. This Protocol is submitted to the Finance Committee for information.

  9. Co-operating for gold open access without APCs

    Directory of Open Access Journals (Sweden)

    Martin Paul Eve

    2015-03-01

    Full Text Available While article processing charges (APCs are emerging as a key way in which existing publishers can adapt to gold open access (OA, this mode is problematic in many ways. Considering the existing subscription publication ecosystem as a risk/cost-pooling mechanism leads to the conclusion that APCs are a concentration of risk that may come with damaging institutional consequences, particularly in the humanities disciplines. Consortial and co-operative modes of funding gold OA, however, do not come with these drawbacks but are susceptible to ‘free riders’. In this article, the theoretical backdrop to these models is addressed and the range of current offerings evaluated. Noting that classical economic incentives do not seem to operate in a world of inter-library loans, the article ends with a description of the model that is being implemented for the 'Open Library of Humanities' initiative, funded by the Andrew W Mellon Foundation.

  10. Co-operative Principle of Conversation and Humor in English

    Institute of Scientific and Technical Information of China (English)

    付岚

    2012-01-01

    Language humor is a usual phenomenon in human communication. It is an interdisciplinary subject connected with a wide range of learning. Up to now, a great deal of research has been done from the viewpoint of psychology and sociology. In the field of linguistics, some explorations have already been made in regard to its semantic and rhetorical aspects, but due attention has not been paid to it in pragmatics in that in everyday verbal communication, humorous utterances are easy to enjoy but hard to define. Apart from its capability of laughter-making, language humor is more often than not, produced to implicitly perform some communicative functions, not achievable by explicit expressions. This the - sis, based on the fruitful studies of humor, attempts to investigate the mechanisms of English humor from the perspective of a new theory 一 Co- operative Principle.

  11. New Zealand signs up to co-operate with CERN

    CERN Multimedia

    Patrice Loïez

    2003-01-01

    On 4 December 2003 a Memorandum of Understanding (MoU) between CERN and the government of New Zealand was signed in the presence of Peter Hamilton, New Zealand's ambassador to Switzerland. This MoU concerns the further development of scientific and technical co-operation in high-energy particle physics between Ernest Rutherford's birthplace and CERN, which now hosts one of the world's most ambitious scientific endeavours, the Large Hadron Collider (LHC).    In anticipation of the MoU, two New Zealand universities (the University of Auckland and the University of Canterbury in Christchurch) have already joined the CMS collaboration to work on pixel detectors, where they can benefit from the expertise of the pixel group at the Paul Scherrer Institute. These detectors are not only valuable in high-energy particle physics, but also serve medical applications.

  12. Signature of the Co-operation Agreement between CERN and JINR, Dubna concerning Scientific and Technical Co-operation in High-Energy Physics

    CERN Multimedia

    Maximilien Brice

    2010-01-01

    On Thursday 28 January, CERN Director-General Rolf Heuer and JINR Director Alexei Sissakian signed a new enlarged co-operation agreement to continue and enhance the scientific and technical co-operation of the two institutes in the field of high-energy physics.

  13. Giant frequency down-conversion of the dancing acoustic bubble

    Science.gov (United States)

    Deymier, P. A.; Keswani, M.; Jenkins, N.; Tang, C.; Runge, K.

    2016-11-01

    We have demonstrated experimentally the existence of a giant frequency down-conversion of the translational oscillatory motion of individual submillimeter acoustic bubbles in water in the presence of a high frequency (500 kHz) ultrasonic standing wave. The frequency of the translational oscillations (~170 Hz) is more than three orders of magnitude smaller than that of the driving acoustic wave. We elucidate the mechanism of this very slow oscillation with an analytical model leading to an equation of translational motion of a bubble taking the form of Mathieu’s equation. This equation illuminates the origin of the giant down conversion in frequency as arising from an unstable equilibrium. We also show that bubbles that form chains along the direction of the acoustic standing wave due to radiation interaction forces exhibit also translation oscillations that form a spectral band. This band extends approximately from 130 Hz up to nearly 370 Hz, a frequency range that is still at least three orders of magnitude lower than the frequency of the driving acoustic wave.

  14. Energy Technology Initiatives - Implementation Through Multilateral Co-operation

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2010-07-15

    New technologies will be critical in addressing current global energy challenges such as energy security. More must be done, however, to push forward the development and deployment of the technologies we need today and will need in the future. Government leaders have repeatedly underlined the crucial role of industry and businesses in advancing energy technologies and the importance of strong collaboration among all stakeholders to accelerate technology advances. To attain these goals, increased co-operation between industries, businesses and government energy technology research is indispensable. The public and private sectors must work together, share burdens and resources, while at the same time multiplying results and outcomes. The 42 multilateral technology initiatives (Implementing Agreements) supported by the IEA are a flexible and effective framework for IEA member and non-member countries, businesses, industries, international organisations and non-government organisations to research breakthrough technologies, to fill existing research gaps, to build pilot plants, to carry out deployment or demonstration programmes -- in short to encourage technology-related activities that support energy security, economic growth and environmental protection. This publication highlights the significant accomplishments of the IEA Implementing Agreements.

  15. Maternal-fetal resource allocation: co-operation and conflict.

    Science.gov (United States)

    Fowden, A L; Moore, T

    2012-11-01

    Pregnancy is generally a co-operative interaction between mother and fetus in which the evolutionary genetic interests of both benefit from production of healthy offspring. While this view is largely supported by empirical data, Kinship Theory predicts that mother and fetus will disagree over the optimum level of maternal investment that maximises their respective fitnesses. This conflict will be more evident with polyandrous than monogamous mating systems, when resources are scarce and in late gestation when the fetus is growing maximally, particularly if conceptus mass is large relative to maternal mass. As the site of nutrient transfer, the placenta is pivotal in the tug-of-war between mother and fetus over resource allocation. It responds to both fetal signals of nutrient demand and maternal signals of nutrient availability and, by adapting its phenotype, regulates the distribution of available resources. These adaptations involve changes in placental size, morphology, transport characteristics, metabolism and hormone bioavailability. They are mediated by key growth regulatory, endocrine and nutrient supply genes responsive to mismatches between nutrient availability and the fetal genetic drive for growth. Indeed, evolution of genomic imprinting and placental secretion of hormones are believed to have been driven by maternal-fetal conflict over resource allocation. Although many of the specific mechanisms involved still have to be identified, the placenta confers optimal fitness on the offspring for its developmental environment by balancing conflict and cooperation in the allocation of resources through generation of nutrient transport phenotypes specific to the prevailing nutritional conditions and/or fetal genotype.

  16. Energy transfer mechanisms in Tb{sup 3+}, Yb{sup 3+} codoped Y{sub 2}O{sub 3} downconversion phosphor

    Energy Technology Data Exchange (ETDEWEB)

    Yuan Junlin; Zhao Jingtai; Zhang Zhijun; Chen Haohong; Yang Xinxin [Shanghai Institute of Ceramics, Chinese Academy of Sciences, 1295 Dingxi Road, Shanghai 200050 (China); Zeng Xiaoyan [Institute of Solid State Physics, Chinese Academy of Sciences, PO Box 1129, Hefei 230031 (China)], E-mail: jtzhao@mail.sic.ac.cn

    2008-05-21

    Tb{sup 3+} and Yb{sup 3+} co-activated luminescent material that can cut one photon of around 483 nm into two NIR photons of around 1000 nm could be used as a downconversion luminescent convertor in front of crystalline silicon solar cell panels to reduce thermalization loss of the solar cell. The Tb{sup 3+} {yields} Yb{sup 3+} energy transfer mechanisms in the UV-blue region in Y{sub 2}O{sub 3} phosphor were studied by PL excitation spectra and time-resolved luminescence, from which the charge transfer mechanism and the cooperative transfer mechanism were identified. Tb{sup 3+} ions in the 4f{sup 7}5d{sup 1} state relax down to the {sup 5}D{sub 4} level and cooperatively transfer energy to two Yb{sup 3+} ions, which is followed by the emission of two photons ({lambda} {approx} 1000 nm). It was found in the (Y{sub 0.79}Tb{sub 0.01}Yb{sub 0.20}){sub 2}O{sub 3} sample that 37% of the Tb{sup 3+} ions at the {sup 5}D{sub 4} level transfer energy to two neighbouring Yb{sup 3+} ions by the cooperative energy transfer mechanism Tb{sup 3+} ({sup 5}D{sub 4}) {yields} 2Yb{sup 3+} ({sup 2}F{sub 5/2}). Unfortunately, the high Yb{sup 3+} concentration leads to severe concentration quenching that significantly reduces the external quantum efficiency. Moreover, the energy of the Tb{sup 3+} 4f{sup 7}5d{sup 1} state can also be lost non-radiatively or transferred to the Yb{sup 3+} {sup 2}F{sub 5/2} state via the charge transfer state Tb{sup 4+}-Yb{sup 2+}. In conclusion, RE{sup 3+} (RE = Ce, Pr, Tb) with strong absorption in the UV region is not an appropriate sensitizer of Tb{sup 3+} in Tb{sup 3+}-Yb{sup 3+} codoped downconversion phosphor.

  17. Down-conversion IM-DD RF photonic link utilizing MQW MZ modulator.

    Science.gov (United States)

    Xu, Longtao; Jin, Shilei; Li, Yifei

    2016-04-18

    We present the first down-conversion intensity modulated-direct detection (IM-DD) RF photonic link that achieves frequency down-conversion using the nonlinear optical phase modulation inside a Mach-Zehnder (MZ) modulator. The nonlinear phase modulation is very sensitive and it can enable high RF-to-IF conversion efficiency. Furthermore, the link linearity is enhanced by canceling the nonlinear distortions from the nonlinear phase modulation and the MZ interferometer. Proof-of-concept measurement was performed. The down-conversion IM-DD link demonstrated 28dB improvement in distortion levels over that of a conventional IM-DD link using a LiNbO3 MZ modulator.

  18. Digital coherent receiver employing photonic downconversion for phase modulated radio-over-fibre links

    DEFF Research Database (Denmark)

    Zibar, Darko; Caballero Jambrina, Antonio; Guerrero Gonzalez, Neil

    2009-01-01

    A digital coherent receiver employing photonic downconversion is presented and experimentally demonstrated for phase-modulated radio-over-fibre optical links. The receiver is capable of operating at frequencies exceeding the bandwidth of electrical analog-to-digital converter by using photonic...... downconversion to translate the high-frequency input RF signal to the operating frequency range of the analog-to-digital converter. First, using linear digital demodulation scheme we measure SFDR of the link at microwave frequency of 5 GHz. Thereafter, successful signal demodulation of 50 Mbit/s binary phase...... shift keying (BPSK) modulated data signal at 5 GHz RF carrier frequency is experimentally demonstrated by using an analog-to-digital converter with only 1 GHz bandwidth. We successfully demonstrate signal demodulation, using the proposed digital coherent receiver with photonic downconversion, after 40...

  19. New passive decoy-state quantum key distribution with thermal distributed parametric down-conversion source

    Science.gov (United States)

    Wei, Jie; Zhang, Chun-Hui; Wang, Qin

    2017-02-01

    We present a new scheme on implementing the passive quantum key distribution with thermal distributed parametric down-conversion source. In this scheme, only one-intensity decoy state is employed, but we can achieve very precise estimation on the single-photon-pulse contribution by utilizing those built-in decoy states. Moreover, we compare the new scheme with other practical methods, i.e., the standard three-intensity decoy-state BB84 protocol using either weak coherent states or parametric down-conversion source. Through numerical simulations, we demonstrate that our new scheme can drastically improve both the secure transmission distance and the key generation rate.

  20. “Co-operative identity†: A theoretical concept for economic analysis of practical co-operation dynamics

    OpenAIRE

    Szabo, Gabor G.

    2007-01-01

    Farmers’ problems and co-ordination of agricultural activities cannot be solved simply by EU and/or government support, or by private market co-ordination institutions. Emerging producer groups and co-operatives seem vital in achieving bargaining power. Theoretically, and according to Western European (Dutch, Danish etc.) and US practical experience, one of the major important private institutions that can strengthen producers and help co-ordinate (agricultural) chains is the co-operative e...

  1. 'Part of the solution': Developing sustainable energy through co-operatives and learning

    Science.gov (United States)

    Duguid, Fiona C. B.

    After five years of development, WindShare Co-operative in Toronto, Ontario became the first urban wind turbine in North America and the first co-operatively owned and operated wind turbine in Canada. The development of WindShare Co-operative has spurred the growth of a green energy co-operative sector in Ontario. This study, which included 27 interviews and a focus group with members of WindShare Co-operative, focuses on the roles of community-based green energy co-operatives in advancing sustainable energy development and energy literacy. Sustainable energy development is firmly rooted in the triple bottom line of environmental, social and economic success, and green energy co-operatives can be a way to help achieve those successes. Green energy co-operatives are structures for providing renewable energy generation or energy conservation practices, both of which have important environmental impacts regarding climate change and pollution levels. Co-operative structures are supported by processes that include local ownership, democracy, participation, community organizing, learning and social change. These processes have a significant social impact by creating a venue for people to be directly involved in the energy industry, by involving learning through participation in a community-based organization, and by advancing energy literacy within the membership and the general public. In regards to the economic impacts, green energy co-operatives foster a local economy and local investment opportunities, which have repercussions regarding building expertise within Ontario's green energy and co-operative development future, and more generally, captures members' interest because they have a direct stake in the co-operative. This thesis shows that green energy co-operatives, like WindShare, play an important role in advancing sustainable energy development, energy literacy and the triple bottom line. Members of WindShare expressed resounding feelings of pride, efficacy

  2. Understanding the influence of nanoenvironment on luminescence of rare-earth ions

    Indian Academy of Sciences (India)

    Pushpal Ghosh; Amitava Patra

    2005-11-01

    This paper presents an overview of the recent results on upconversion and photoluminescence of rare-earth ions in nanoenvironments. The role of the rare-earth ion concentration, crystal size and crystal phase on the up- and downconversion emission of rare-earth ions in oxide nanocrystals and their underlying mechanisms are discussed. It is also found that the luminescence lifetime of the excited state rare-earth ions is sensitive to the particle crystalline phase and size. The analysis suggests that the modifications of radiative and nonradiative relaxation mechanisms are due to local symmetry structure of the host lattice and crystal size respectively.

  3. Downconversion in Pr{sup 3+}–Yb{sup 3+} co-doped ZBLA fluoride glasses

    Energy Technology Data Exchange (ETDEWEB)

    Maalej, O. [Institut des Molécules et Matériaux du Mans, UMR CNRS 6283, Université du Maine, Av. O. Messiaen, 72085 Le Mans cedex 09 (France); Laboratoire de Chimie Inorganique, Université de Sfax, Faculté des Sciences de Sfax, BP 1171, 3000 Sfax (Tunisia); Boulard, B., E-mail: brigitte.boulard@univ-lemans.fr [Institut des Molécules et Matériaux du Mans, UMR CNRS 6283, Université du Maine, Av. O. Messiaen, 72085 Le Mans cedex 09 (France); Dieudonné, B. [Institut des Molécules et Matériaux du Mans, UMR CNRS 6283, Université du Maine, Av. O. Messiaen, 72085 Le Mans cedex 09 (France); Ferrari, M. [Institute of Photonics and Nanotechnology (CNR), CSMFO Lab., Via alla Cascata 56/C Povo, 38123 Trento (Italy); Dammak, M. [Laboratoire de Physique Appliquée, Groupe des Matériaux Luminescents, Université de Sfax, Faculté des Sciences de Sfax, BP 1171, 3000 Sfax (Tunisia); Dammak, M. [Laboratoire de Chimie Inorganique, Université de Sfax, Faculté des Sciences de Sfax, BP 1171, 3000 Sfax (Tunisia)

    2015-05-15

    Fluorozirconate ZBLA glasses with molar composition 57ZrF{sub 4}–34BaF{sub 2}–5LaF{sub 3}–4AlF{sub 3}–0.5PrF{sub 3}–xYbF{sub 3} (from x=0 to 10) were synthesized to evaluate the rate of the conversion of visible photons into infrared photons. The emission spectra in the near infrared (NIR) at 950–1100 nm and the luminescence decays in the visible and NIR indicate an energy transfer from Pr{sup 3+} to Yb{sup 3+} upon blue excitation of Pr{sup 3+} at 440 nm. The energy transfer efficiency increases with Yb{sup 3+} concentration to reach 86% with 0.5Pr{sup 3+}–10Yb{sup 3+} co-doping (in mol%). However, the quenching of the Yb{sup 3+} emission strongly reduces the efficiency of the downconversion process: the decay time values decrease from 600 µs (x=0.5 mol%) to 85 µs (x=10 mol%). - Highlights: • We synthesized 0.5Pr{sup 3+}–xYb{sup 3+} co-doped ZBLA glasses (from x=0 to 10 mol %). • Photoluminescence of Yb{sup 3+} was observed at 980 nm under blue excitation. • Time resolved measurements have been performed in the visible and near infrared. • Energy transfer efficiency from Pr{sup 3+} to Yb{sup 3+} reaches 86% in 0.5 Pr{sup 3+}–10Yb{sup 3+} glass.

  4. Fourth-Order Interference in Femtosecond Spontaneous Parametric Down-Conversion

    Institute of Scientific and Technical Information of China (English)

    JIANG Yun-Kun; SHI Bao-Sen; LI Jian; FAN Xiao-Feng; GUO Guang-Can

    2000-01-01

    We report a fourth-order interference experiment in which pairs of photons are produced in spontaneous parametric down-conversion pumped by femtosecond pulses interfere in a Hong-Ou-Mandel interferometer. The visibilityof the interference is (64±4)%, exceeding the bound of 50% predicted by classical interference theory.

  5. Microwave photonic frequency down-conversion link based on intensity and phase paralleled modulation

    Science.gov (United States)

    Li, Jingnan; Wang, Yunxin; Wang, Dayong; Du, Haozheng; Zhou, Tao; Zhong, Xin; Yang, Dengcai; Li, Hongli

    2016-01-01

    A photonic microwave down-conversion approach is proposed and experimentally demonstrated based on a Mach-Zehnder modulator paralleled with a phase modulator. The incident radio frequency signal and the local oscillator signal are feed to the MZM and PM, respectively, and these two modulated optical signals interfere in the coupler. The useless higher-order sidebands are removed by a tunable optical band-pass filter. The principle of microwave frequency down-conversion is analyzed theoretically, the MZM and PM paralleled frequency down-conversion system is built. Then the performance of system is tested, and the experimental results show that the spurious-free dynamic range achieves 104.8 dB:Hz2/3. Compared to the conventional MZM-MZM cascaded system, the SFDR has been improved by 16 dB. The MZM and PM paralleled frequency down-conversion system can balance the intensity of the two coherent beams easily, and only single DC bias is needed. The proposed method possesses simple structure and high dynamic range.

  6. A Quantized Analog Delay for an ir-UWB Quadrature Downconversion Autocorrelation Receiver

    NARCIS (Netherlands)

    Bagga, S.; Zhang, L.; Serdijn, W.A.; Long, J.R.; Busking, E.B.

    2005-01-01

    A quantized analog delay is designed as a requirement for the autocorrelation function in the quadrature downconversion autocorrelation receiver (QDAR). The quantized analog delay is comprised of a quantizer, multiple binary delay lines and an adder circuit. Being the foremost element, the quantizer

  7. Simulating spontaneous parametric down-conversion using classical light: Conference paper

    CSIR Research Space (South Africa)

    Zhang, Y

    2014-08-01

    Full Text Available We present a simple way of simulating Spontaneous parametric down-conversion (SPDC) by modulating a classical laser beam with two spatial light modulators (SLM) through a back projection setup. This system has the advantage of having very high...

  8. Observation of Image Transfer and Phase Conjugation in Stimulated Down-Conversion

    CERN Document Server

    Souto-Ribeiro, P H; Almeida, M P; Huguenin, J A; Dos Santos, B C; Khoury, A Z

    2001-01-01

    We observe experimentally the transfer of angular spectrum and image formation in the process of stimulated parametric down-conversion. Images and interference patterns can be transferred either from the pump or the auxiliary laser beams to the stimulated down-converted one. The stimulated field propagates as the complex conjugate of the auxiliary laser. The phase conjugation is observed through intensity pattern measurements.

  9. Experimental verification of high spectral entanglement for pulsed waveguided spontaneous parametric down-conversion

    DEFF Research Database (Denmark)

    Avenhaus, M.; Chekhova, M. V.; Krivitsky, Leonid

    2009-01-01

    We study the spectral properties of spontaneous parametric down-conversion (SPDC) in a periodically poled waveguided structure of potassium-titanyl-phosphate (KTP) crystal pumped by ultrashort pulses. Our theoretical analysis reveals a strongly entangled and asymmetric structure of the two...

  10. Two-Photon Interference with the Type Ⅱ Spontaneous Parametric Down-Conversion

    Institute of Scientific and Technical Information of China (English)

    江云坤; 史保森; 李剑; 段开敏; 范晓锋; 郭光灿

    2001-01-01

    The two-photon polarized entangled state is generated from the type Ⅱ spontaneous parametric down-conversion pumped by a femtosecond pulse. The two-photon interference is observed in the Hong-Ou-Mandel interferometer. The high visibility of the interference is restored with narrow band interference filters placed in front of the detectors.

  11. Using Critical Problem Solving to Plan Inter-Organisational Co-operation in e-Customs

    NARCIS (Netherlands)

    Ponisio, M.L.; Eck, van P.A.T.; Riemens, L.

    2008-01-01

    The purpose of this paper is to present a systematic approach to plan assessment of electronic co-operation between customs organisations of different countries (e-Customs). Thorough assessment is of paramount importance, as co-operation in electronic networks usually requires considerable up-front

  12. Comparative study on membership legislation in Canadian and Chinese agricultural co-operative laws

    Institute of Scientific and Technical Information of China (English)

    CHU Zhihong; GUO Xiangyu

    2007-01-01

    For centuries, groups of people desiring to supply themselves with goods, to market their products, or to obtain services of various kinds on a co-operative basis, have made increasing use of co-operative associations to achieve these purposes. During the period, legislation designed especially for the incorporation and conduct of such associations has been enacted by different counties.Since a co-operative is established and carried on by and for the use of its members, this essay makes a comparison between Canadian and Chinese co-operative laws in terms of membership in the aspects of qualifications, rights and obligations and withdrawal of membership, so as to probe the function of co-operative legislation and find some enlightment from it.

  13. 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....

  14. Regulatory and Legal Provision of Trans-border Co-operation of Industrial Enterprises

    Directory of Open Access Journals (Sweden)

    Kuzmin Oleh Ye.

    2013-12-01

    Full Text Available The goal of the article lies in the study of regulatory and legal provision of trans-border co-operation of enterprises. Having analysed scientific works of many scientists and considered a significant number of regulatory and legal acts, the authors systemised the component elements of the legal provision of trans-border co-operation of enterprises and showed a hierarchical connection between them. In the result of the study the article presents a rather complete system of regulatory and legal provision of trans-border co-operation of enterprises and provides a complete list of regulatory and legal acts directed at regulation of such a co-operation. The prospects of further studies in this direction are development of proposals on improvement of the existing regulatory and legal base of Ukraine in the sphere of trans-border co-operation and development of efficient ways of development of trans-border co-operation of enterprises. Urgency of the study is confirmed by the fact that development of trans-border co-operation of enterprises can become a real tool of facilitation of faster entering of Ukraine into European economic environment.

  15. Ideological leaning and praxis of housing co-operatives in South Africa: Matters arising

    Directory of Open Access Journals (Sweden)

    Richard Jimoh

    2013-06-01

    Full Text Available Social movements came about as a result of dissatisfaction felt by society from the status quo. They present their grievances through demonstrations, strikes, riots, occupation of land, boycott of business or by the development of social and economic alternatives such as self-help schemes or saving clubs. In South Africa, people join housing co-operatives because it takes a long time to wait for the Reconstruction Development Project (RDP houses promised by the Government. The leaning of 5 housing co-operatives was examined within the context of ideology and praxis that are components of triad model. This was done through multi-case study whereby the chairpersons of the housing co-operatives were interviewed using structured interview format. Findings from the study indicated that all the housing co-operatives were not open and voluntary; also, the housing co-operatives were not administered the same way. In all, efforts were put in by the housing co-operatives in engendering the ideology of co-operatives on one hand and the government on the other hand in providing the necessary subsidy so that the gap in the housing deficit could be bridged since this fitted its policy on housing. 

  16. Efficient frequency downconversion at the single photon level from the red spectral range to the telecommunications C-band.

    Science.gov (United States)

    Zaske, Sebastian; Lenhard, Andreas; Becher, Christoph

    2011-06-20

    We report on single photon frequency downconversion from the red part of the spectrum (738 nm) to the telecommunications C-band. By mixing attenuated laser pulses with an average photon number per pulse telecommunications wavelengths.

  17. Success and failure of firms' innovation co-operations: The role of intermediaries and reciprocity

    DEFF Research Database (Denmark)

    Cantner, U.; Meder, A.; Wolf, T.

    2011-01-01

    attempts to fill this gap by investigating the possible presence of two problems in co-operation: the lack of intermediation and of reciprocity. Based on data gathered for firms in two German regions and one French region, we find that the success of co-operation projects depends on the perceived...... importance, rather than on the perceived quality, of intermediate actors. Hence, the major problem for intermediating suitable partners is more related to communication than it is a programmatic issue. Trust and reciprocity in co-operation between firms is found to be relevant ex-post in the sense of being...

  18. Proceedings of International Symposium on Energy Co-operation in North East Asia

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-06-01

    This proceedings are for the International Symposium on Energy Co-operation in North-East Asia, organized by Korea Energy Economics Institute, Institute of Energy Economics, Japan, and United Nations Economic and Social Commission for Asia and the Pacific, held on June 2001 at Sheraton Walker Hill Hotel in Seoul, Korea. The major themes discussed are following: 1.Energy Profile, Outlook and Perspectives on Regional Co-operation in Northeast Asia 2.Future Challenges in the Energy Sector in Northeast Asia 3.Perspectives of Energy Co-operation in Northeast Asia.

  19. Developing Cultural Tourism Through Cross-Sector Co-operation: Evidence from the West of Ireland

    OpenAIRE

    Mottiar, Ziene; Quinn, Bernadette; Ryan, Theresa

    2016-01-01

    Studies of co-operative activity in the tourism literature focus largely on linkages between tourism firms and little has been done to examine co-operation between tourism firms and those in other sectors. Yet the inter-dependency that exits between tourism and other sectors in product development is clearly apparent. One such example is in the production of cultural tourism where co-operation between the cultural and tourism sectors is a necessity. This paper reports on the findings of a pro...

  20. Co-operation agreement between the European Organization for Nuclear Research (CERN) and the Government of People's Republic of Bangladesh concerning Education, Scientific and Technical Co-operation in High-Energy Physics

    CERN Document Server

    2014-01-01

    Co-operation agreement between the European Organization for Nuclear Research (CERN) and the Government of People's Republic of Bangladesh concerning Education, Scientific and Technical Co-operation in High-Energy Physics

  1. Coordination polymer core/shell structures: Preparation and up/down-conversion luminescence.

    Science.gov (United States)

    Li, Bingmei; Xu, Hualan; Xiao, Chen; Shuai, Min; Chen, Weimin; Zhong, Shengliang

    2016-10-01

    Coordination polymer (CP) core-shell nanoparticles with Gd-based CP (GdCP) as core and Eu-based CP (EuCP) as shell have been successfully prepared. Allantoin was employed as the organic building block without the assistance of any template. The composition, size and structure of the core-shell nanospheres were well characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray (EDX), powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FT-IR), thermo-gravimetric analysis (TG). Results show that the resultant cores are uniform nanospheres with diameter of approximately 45nm, while the diameters of the core-shell nanospheres are increased to approximately 60nm. The core-shell products show enhanced luminescence efficiency than the core under 980nm laser excitation and decreased down-conversion luminescence when excited at 394nm.

  2. Optical temperature sensing based on the luminescence from YAG:Pr transparent ceramics

    Science.gov (United States)

    Hu, Song; Lu, Chunhua; Liu, Xiaoxia; Xu, Zhongzi

    2016-10-01

    The YAG:Pr transparent ceramic was fabricated using a conventional solid-state reactive method to explore its possible application in optical thermometry. Photoluminescence and temperature-dependent luminescence were elaborately investigated under 452 nm excitation. The ceramic showed two intrinsic emission bands at 488 and 594 nm, which were attributed to characteristic Pr3+: 3P0 → 3H4 and 3P1 → 3H6 transitions, respectively. Down-conversion emissions from the two thermally coupled excited states of Pr3+ were recorded in the temperature range of 293-593 K. The Boltzmann distribution theory was adopted to interpret the temperature-dependent luminescence of Pr3+. The temperature sensitivity exhibited an increasing trend with the increase of temperature, typically, 0.0025 K-1 at 593 K. The results indicated that the present ceramic was a promising candidate for optical temperature sensor.

  3. 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.

  4. Solvency and Performance of French Wineries in Times of Declining Sales: Co-operatives and Corporations

    Directory of Open Access Journals (Sweden)

    Francis Declerck

    2012-12-01

    Full Text Available The paper assesses the ability of French wineries to prevail over the crisis of French wine in the years 2000. Corporations are distinguished from co-operatives:Over the 2000-2006 period in spite of sales fluctuations, French wineries did not increase their financial debt level substantially. Such result supports the traditional static trade-off theory (TOT. Co-operatives were able to absorb part of the impact of the wine crisis at the expense of their members, in increasing account payables to member. Corporations have not increased trade account payables to vine growers.In the mid-2000s, the French wine crisis has not been strong enough to shake the financial structure of co-operatives and corporations. But co-operatives look more affected. However, sales of French wines dropped a lot more in 2009 and financial data are not yet available to observe the consequences.

  5. Organization for security and co-operation in Europe mission to Georgia / Joe McDonagh

    Index Scriptorium Estoniae

    McDonagh, Joe

    2003-01-01

    22.-23. septembrini 2003 Vilniuses toimunud seminaril "South Caucasus: making the best use of external assistance for stability building and for co-operation with NATO" esitatud ettekanne OSCE missiooni tegevusest Gruusias

  6. Organization for security and co-operation in Europe mission to Georgia / Joe McDonagh

    Index Scriptorium Estoniae

    McDonagh, Joe

    2003-01-01

    22.-23. septembrini 2003 Vilniuses toimunud seminaril "South Caucasus: making the best use of external assistance for stability building and for co-operation with NATO" esitatud ettekanne OSCE missiooni tegevusest Gruusias

  7. A study of personality of leader and style of his co-operation in sporting command

    Directory of Open Access Journals (Sweden)

    Smolar I.I.

    2012-12-01

    Full Text Available The personality features of leader of sporting command and style of his co-operation are considered. The problems of adjusting and optimization of co-operation of leader and other players of command are selected in achievement of the set team purpose. 37 skilled sportsmen-handballers took part in research. An informal structure is exposed in commands, leaders and followers are certain. The quantitative indexes of personality features of leader, follower of sporting command are certain. Style of co-operation of leader and follower (prevailing and goodwill and quality is exposed personalities which will be realized by them in a sporting command. It is set that in interpersonality co-operation a leader will realize dominant style, and follower equal will realize dominant and benevolent styles.

  8. Shariah Governance Framework For Islamic Co-Operatives As An Integral Social Insitution In Malaysia

    OpenAIRE

    Muhammad Issyam Itam; Rusni bt Hasan; Syed Musa Alhabshi

    2017-01-01

    In Malaysia, Islamic cooperatives are recognized as providers of some form of Islamic financial service similar to Islamic Banks and Takaful Operators. An Islamic Co-operative refers to a co-operative conducting activities and businesses based on Shariah principles. Being a non-banking financial institution, its main objective is to enhance social economic welfare of its members. As a form of captive social institution, it enables the less economically privileged members of society to pool re...

  9. Structural changes in the development of European co-operative societes

    OpenAIRE

    Josefina FERNÁNDEZ GUADAÑO

    2006-01-01

    In spite of the wealth of experience which co-operative societies now have behind them, they have not gained uniform recognition across Europe. Supranational authorities such as the European Commission, the UN and the ILO have highlighted the important contribution made by co-operative societies in the creation of employment and in the mobilization of resources particularly at the local level. For several years now, however, two different tendencies in the development of the European...

  10. Competition and Co-operation between Stock Exchanges in Europe - Legal Aspects and Challenges

    DEFF Research Database (Denmark)

    Sørensen, Karsten Engsig; Clausen, Nis Jul

    2002-01-01

    The article analysis why and how European Stock Exchanges enters into alliances. On the background of alliances as Norex, Euronext and the planned iX the different areas and types of co-operation is discussed.......The article analysis why and how European Stock Exchanges enters into alliances. On the background of alliances as Norex, Euronext and the planned iX the different areas and types of co-operation is discussed....

  11. Local and Sustainable Food Supply: The Role of European Retail Consumer Co-operatives

    Directory of Open Access Journals (Sweden)

    Martin Hingley

    2012-03-01

    Full Text Available  This paper investigates the rationale for local and sustainable food systems and retailer co-operatives as their entry points within local conditions. Emphasis is on localised food networks and connection between socially as well as environmentally sustainable production, distribution and consumption. Investigated is the premise that co-operative organisational structures, for reasons of their long-term socially responsible origins are at the forefront of development of local and sustainable food systems and are thereby in a position to offer a specific contribution to market development. Two key research questions are proposed: Firstly, is there a pre-determination of co-operatives to issues of sustainable and local food sourcing given the historical and practical context of their ethical/socially responsible and stakeholder-based business model? Secondly, do co-ops express support for re-localising food systems and what contribution do they make concerning sustainable food and their relationships with local food suppliers? The method of investigation is through a two country retailer co-operative sector analysis and comparison (Finland and Italy. The enquiry is qualitative and exploratory in nature in the form of an embedded, multiple case design. The paper makes practical and theoretical contribution to knowledge concerning interpretation of ‘localness’ in food, the role of co-operatives and the co-operative ethos in sustainable food systems and the development of the local food economy. Results of the study show a positive relationship between co-operative ethos and (social sustainability in local food, but the de-centralised nature of retailer co-operation also provides a barrier to replication of good practice.

  12. Characterization of a Spontaneous Parametric Downconversion Source for Use in Single Photon Tests of Quantum Mechanics

    Science.gov (United States)

    Alexander, Preston; McDonld, Jackson; Harrington, Jason; Smith, R. Seth

    2014-03-01

    During the past year, a quantum optics laboratory was constructed and tested at Francis Marion University. A spontaneous parametric downconversion source was used to create pairs of correlated photons for use in single photon tests of quantum mechanics. Photons from a spontaneous parametric downconversion source were detected with single photon counting modules that were purchased through the Advanced Laboratory Physics Association (ALPHA). The effect of pump polarization on the output intensity was studied. Coincidences between pairs of correlated photons were counted and plotted as a function of the angle between the single photon detectors, in order to perform a test of Conservation of Momentum. The laboratory will be used to perform single photon tests of quantum mechanics, including the Grangier experiment, single photon interference, quantum state measurement, and tests of local realism.

  13. Efficient antireflective downconversion Er{sup 3+} doped ZnO/Si thin film

    Energy Technology Data Exchange (ETDEWEB)

    Elleuch, R. [Laboratoire Géoressouces, Matériaux, Environnement et Changements Globaux, Faculté des Sciences de Sfax, Université de Sfax, 3018 Sfax (Tunisia); Salhi, R. [Laboratoire de Chimie Industrielle, École Nationale d' Ingénieur de Sfax, Université de Sfax, 3038 Sfax (Tunisia); Al-Quraishi, S.I. [King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Deschanvres, J.-L. [Laboratoire des Matériaux et du Génie Physique, 3 Parvis Louis Néel, BP 257, 38016 Grenoble (France); Maâlej, R., E-mail: ramzi.maalej@fss.rnu.tn [Laboratoire Géoressouces, Matériaux, Environnement et Changements Globaux, Faculté des Sciences de Sfax, Université de Sfax, 3018 Sfax (Tunisia)

    2014-05-01

    This study is an investigation of the potential of Er doped ZnO thin films for downconversion photons and an antireflective layer when placed in front of the silicon solar cells. We optimized the properties of the film with appropriate deposition conditions on Si (111) substrate by aerosol assisted chemical vapor deposition (AACVD) process. An enhancement of both crystallinity and optical response was achieved in the case of film doped with 2.504 at.% Er{sup 3+}. A low reflectance and high refractive index of the film were obtained at around 632 nm. Downconversion process was also reached for this film under visible excitation to near-infrared (NIR) 980 nm photons useful for Si solar cell.

  14. Producing high fidelity single photons with optimal brightness via waveguided parametric down-conversion

    OpenAIRE

    Laiho K.; Cassemiro K.N.; Silberhorn C.

    2009-01-01

    Parametric down-conversion (PDC) offers the possibility to control the fabrication of non-Gaussian states such as Fock states. However, in conventional PDC sources energy and momentum conservation introduce strict frequency and photon number correlations, which impact the fidelity of the prepared state. In our work we optimize the preparation of single-photon Fock states from the emission of waveguided PDC via spectral filtering. We study the effect of correlations via photon number resolving...

  15. Monte Carlo study of PbSe quantum dots as the fluorescent material in luminescent solar concentrators.

    Science.gov (United States)

    Wilton, S R; Fetterman, M R; Low, J J; You, Guanjun; Jiang, Zhenyu; Xu, Jian

    2014-01-13

    In this paper, Monte Carlo simulations were performed to determine the potential efficiencies of luminescent solar concentrator (LSC) systems using PbSe quantum dots (QDs) as the active fluorescent material. The simulation results suggest that PbSe QD LSCs display good absorption characteristics, but yield limited LSC power conversion efficiency due to self-absorption and down-conversion loss. It is proposed that the self-absorption loss can be reduced by utilizing Förster resonance energy transfer between two different sizes of PbSe QDs, yielding pronounced improvement in the optical efficiency of LSCs.

  16. On-the-fly decoding luminescence lifetimes in the microsecond region for lanthanide-encoded suspension arrays

    Science.gov (United States)

    Lu, Yiqing; Lu, Jie; Zhao, Jiangbo; Cusido, Janet; Raymo, Françisco M; Yuan, Jingli; Yang, Sean; Leif, Robert C.; Huo, Yujing; Piper, James A.; Paul Robinson, J; Goldys, Ewa M.; Jin, Dayong

    2014-01-01

    Significant multiplexing capacity of optical time-domain coding has been recently demonstrated by tuning luminescence lifetimes of the upconversion nanoparticles called ‘τ-Dots’. It provides a large dynamic range of lifetimes from microseconds to milliseconds, which allows creating large libraries of nanotags/microcarriers. However, a robust approach is required to rapidly and accurately measure the luminescence lifetimes from the relatively slow-decaying signals. Here we show a fast algorithm suitable for the microsecond region with precision closely approaching the theoretical limit and compatible with the rapid scanning cytometry technique. We exploit this approach to further extend optical time-domain multiplexing to the downconversion luminescence, using luminescence microspheres wherein lifetimes are tuned through luminescence resonance energy transfer. We demonstrate real-time discrimination of these microspheres in the rapid scanning cytometry, and apply them to the multiplexed probing of pathogen DNA strands. Our results indicate that tunable luminescence lifetimes have considerable potential in high-throughput analytical sciences. PMID:24796249

  17. Preparation and Characterization of Downconversion Luminescent LaVO4: Tm3+ , Yb3+ and Tm3+ /Yb3+ Nanosheets

    Directory of Open Access Journals (Sweden)

    M. Zahedifar

    2012-03-01

    Full Text Available Tm3+ , Yb3+  and Tm3+ /Yb3+  doped LaVO4 nanostructures were synthe- sized for the first time by using the hydrothermal method with the aid of La(CH3CO23 as  lanthanum source in presence of oleic acid as surfactant. The products were characterized by X-ray diffraction (XRD, scanning electron microscopy (SEM, transmission electron microscopy (TEM, photoluminescence (PL spectroscopy and UV– Vis diffuse reflectance spectroscopy. Besides, the effects of activator concentration and sensitizer on the emission intensity were investi- gated. The PL spectrum revealed that the emission intensity decreases with increase in the concentration of Tm3+ , while adding Yb3+ as sensi- tizer causes the emission intensity to increase. The LaVO4: Tm3+ /Yb3+   may possibly have potential application in enhancing the conversion efficiency of dye-sensitized solar cells by increasing the absorption of dyes.

  18. The co-operative model as a means of stakeholder management: An exploratory qualitative analysis

    Directory of Open Access Journals (Sweden)

    Darrell Hammond

    2016-11-01

    Full Text Available The South African economy has for some time been characterised by high unemployment, income inequality and a skills mismatch, all of which have contributed to conflict between business, government and labour. The co-operative model of stakeholder management is examined as a possible mitigating organisational form in this high-conflict environment. International experience indicates some success with co-operative models but they are not easy to implement effectively and face severe obstacles. Trust and knowledge sharing are critical for enabling a co-operative model of stakeholder management, which requires strong governance and adherence to strict rules. The model must balance the tension between optimisation of governance structures and responsiveness to members' needs. Furthermore, support from social and political institutions is necessary. We find barriers to scalability which manifest in the lack of depth of business skills, negative perception of the co-operative model by external stakeholders, government ambivalence, and a lack of willingness on the part of workers to co-operate for mutual benefit.

  19. Co-operation between patient organisations and the drug industry in Finland.

    Science.gov (United States)

    Hemminki, Elina; Toiviainen, Hanna K; Vuorenkoski, Lauri

    2010-04-01

    The aim of the study was to investigate the co-operation between patient organizations and the drug industry in Finland prior to critical discussions on the topic. The data were gathered by a questionnaire survey of 85 patient organisations (response rate 65%, n = 55) and 20 drug firms (response rate 100%) in 2003, and by interviewing 13 organisations and surveying their web-pages and other documents in 2004. In the surveys, half of the patient organisations and 80% of the drug firms considered co-operation important. Most (71%) organisations reported financial support from the drug industry. Most organisations and drug firms had experienced problems. Common problems for organisations were too little or too unpredictable support from industry, and threats to independence and objectivity. Drug firms frequently mentioned unclear rules of co-operation. The patient organisation interviews exhibited similar themes and findings to those found in the surveys, revealing the complexity and importance of co-operation in organisation activities, and the variation between organisations. This case study from Finland showed that co-operation between patient organizations and the drug industry was common, many-sided and not usually transparent. The close connections between patient organizations and commercial companies, particularly drug firms, raise several policy issues and the need for action.

  20. O espaço da cooperativa "amigos do meio ambiente": cooperativa de trabalho ou cooperfraude? "Friends of the environment" co-operative: work co-operative or fraud co-operative?

    Directory of Open Access Journals (Sweden)

    Shirla Patrícia Weber Sterchile

    2011-06-01

    Full Text Available O presente artigo é resultado de pesquisa acadêmica que tem como objeto de estudo-pesquisa "A forma de existir e de ser da Cooperativa dos Agentes Ambientais de Santa Helena 'Amigos do Meio Ambiente' e sua imbricação na Usina de Beneficiamento de Resíduos Sólidos do município de Santa Helena-PR". Verificando o cotidiano profissional, o descontentamento de trabalhadores catadores de matérias recicláveis, o incentivo do gestor municipal para a instalação da usina e a formação da cooperativa, aliado aos postulados do capitalismo, em sua fase tardia, propusemos desconstruir e reconstruir o movimento do objeto em questão a partir da pesquisa teórica e empírica. Para coletar os dados utilizando a técnica de gravação, recorremos à análise documental e à observação. Após esse processo descrevemos e analisamos os conteúdos presentes. Concluímos em nosso estudo-pesquisa, que a Cooperativa - "Amigos do Meio Ambiente", é uma "cooperfraude", legitimada pelo Estado, que suprime os princípios do cooperativismo e exime o capital da raiz da exploração da força de trabalhoThis article resulted from a research aiming at "The form of existence and being of the Co-operative of Environmental Agents from St. Helena - 'Friends of the Environment' - and its imbrication in the Processing Plant of Solid Waste in the city of Santa Helena-PR". Checking the professional practice, the dissatisfaction of workers who collect recycling materials and the City Hall's encouragement to install the plant and to form the Co-operative, together with the tenets of capitalism in its late stage, we proposed to deconstruct and reconstruct the motion of the object studied from the empirical research. After analyzing our data we concluded that the "Friends of the Environment" Co-operative is a "fraud co-operative" legitimized by the State, that suppressed the principles of co-operativism and exempted the capital from the root of exploitation of the workforce

  1. Lanthanide NIR luminescence for telecommunications, bioanalyses and solar energy conversion

    Institute of Scientific and Technical Information of China (English)

    Jean-Claude; G.; Bünzli; V.

    2010-01-01

    Present-day advanced technologies heavily rely on the exciting magnetic and spectroscopic properties of lanthanide ions. In particular, their ability to generate well-characterized and intense near-infrared (NIR) luminescence is exploited in any modern fiber-optic telecommunication network. In this feature article, we first summarize the whereabouts underlying the design of highly luminescent NIR molecular edifices and materials. We then focus on describing the main trends in three applications related to this spectral range: telecommunications, biosciences, and solar energy conversion. In telecommunications, efforts concentrate presently on getting easily processable polymer-based waveguide amplifiers. Upconversion nanophosphors emitting in the visible after NIR excitation are now ubiquitous in many bioanalyses while their application to bio-imaging is still in its early stages; however, highly sensitive NIR-NIR systems start to be at hand for both in vitro and in vivo imaging, as well as dual probes combining magnetic resonance and optical imaging. Finally, both silicon-based and dye-sensitized solar cells benefit from the downconversion and upconversion capabilities of lanthanide ions to harvest UV and NIR solar light and to boost the overall quantum efficiency of these next-generation devices.

  2. Model of the co-operative trade alliance for independent retail networks in Czech Republic

    Directory of Open Access Journals (Sweden)

    Marek Záboj

    2011-01-01

    Full Text Available The main objective of the contribution is proposal of the model of co-operative trade alliance for independent trade alliances with fast-moving consumer goods (FMCG in Czech Republic. Reason of the choice of this topic is sustain of variety of retail formats in Czech market in connection with position small and medium sized trade firms in comparison with transnational trade chains. Independent trade firms face to much bigger competitors operating supermarkets and hypermarkets, namely not even in size of sales area, width and depth of the assortment but also in possibility of negotiation of more profitable trade conditions with their suppliers. Effort of these independent trade firms, which operate mostly just in local or maximally regional market, is then mutual co-operation in form of consumer co-operatives, associations, alliances and networks. These groupings then mainly through common trade negotiation and purchase get for much more advantageous delivery and payment conditions from their suppliers. Besides they can participate in mutual financing of using of promotion instruments. Partial aim of the paper is investigation of opinion and willingness of Czech trade alliances with FMCG to utilize the opportunity of mutual co-operation in common trade alliance. Next partial goal is identification of the factors affecting formation of joint co-operative grouping and its structure, eventually definition of entry conditions which should be fulfilled by individual members.The system approach will be used to realize the given objective. This approach appears as the most suitable in consideration of anticipated structure and character of supposed model. The result will be then proposal of model of mutual co-operation between individual trade alliances.

  3. NATO, Libya operations and intelligence co-operation – a step forward?

    DEFF Research Database (Denmark)

    Svendsen, Adam David Morgan

    2011-01-01

    developments can be opened up for some further analysis, forming the main focus of this article. Ultimately, this article concludes that, over time and albeit while gradual, we have seen what can be regarded as ‘a step forward’ in co-operative intelligence activities in Libya. Although several pressing......"With the ‘fall’ of Tripoli towards the end of August 2011, it has become increasingly apparent that the intelligence co-operation witnessed in Libya during the NATO campaign performed an increasingly important role in realizing operational and strategic ‘successes’. These recent intelligence...

  4. SSI`s International Development Co-operation (SIUS). Annual report 1998

    Energy Technology Data Exchange (ETDEWEB)

    Szendroe, G.; Grapengiesser, S.; Johansson, Gunnar

    1999-04-01

    SSI`s International Development Co-operation (SIUS), the Swedish program for radiation protection work in Central and Eastern Europe, has since its start in 1992 been granted SEK 109 million by the Swedish government. The projects are accessed, planned and performed in close co-operation with partner organisations in Eastern Europe. This report presents the financial status and a summary of the projects, their status and distribution over the countries and project areas. The presentation is updated as of December 1998

  5. Controllable Frequency Entanglement via Auto-Phase-Matched Spontaneous Parametric Down-Conversion

    CERN Document Server

    Walton, Z D; Sergienko, A V; Saleh, B E A; Teich, M C; Walton, Zachary D.; Booth, Mark C.; Sergienko, Alexander V.; Saleh, Bahaa E.A.; Teich, Malvin C.

    2003-01-01

    A new method for generating entangled photons with controllable frequency correlation via spontaneous parametric down-conversion (SPDC) is presented. The method entails initiating counter-propagating SPDC in a single-mode nonlinear waveguide by pumping with a pulsed beam perpendicular to the waveguide. The method offers several advantages over other schemes, including the ability to generate frequency-correlated photon pairs regardless of the dispersion characteristics of the system. Numerical evidence demonstrates the improvement provided by this source in the special case of frequency-correlated two-photon states.

  6. Dispersion-based control of modal characteristics for parametric down-conversion in a multimode waveguide

    CERN Document Server

    Karpinski, Michal; Banaszek, Konrad

    2011-01-01

    We report generation of near-infrared photon pairs in fundamental spatial modes via type-II spontaneous parametric down-conversion in a periodically poled potassium titanyl phosphate nonlinear waveguide supporting multiple transverse modes. This demonstrates experimentally a versatile scheme for complete control over the spatial characteristics of the produced nonclassical light based on careful exploitation of intermodal dispersion. The down-converted photons are characterized by the measurement of the beam quality factors in the heralded regime. Their indistinguishability is verified by the preparation of a polarization-entangled two-photon state shown to violate Bell's inequality.

  7. Control of photon correlations in type II parametric down-conversion

    CERN Document Server

    Andrews, R; Pike, Edward Roy; Sarkar, S; Sarkar, Sarben

    2005-01-01

    In this paper we describe theoretically quantum control of temporal correlations of entangled photons produced by collinear type II spontaneous parametric down-conversion. We examine the effect of spectral phase modulation of the signal or idler photons arriving at a 50/50 beam splitter on the temporal shape of the entangled-photon wave packet . The coincidence count rate is calculated analytically for photon pairs in terms of the modulation depth applied to either the signal or idler beam with a spectral phase filter. It is found that the two-photon coincidence rate can be controlled by varying the modulation depth of the spectral filter.

  8. Ring-shaped spectra of parametric down-conversion and entangled photons that never meet

    CERN Document Server

    Spasibko, Kirill; Murzina, Tatiana; Leuchs, Gerd; Chekhova, Maria

    2016-01-01

    We report on the observation of an unusual type of parametric down-conversion. In the regime where collinear degenerate emission is in the anomalous range of group-velocity dispersion, its spectrum is restricted in both angle and wavelength. Detuning from exact collinear-degenerate phasematching leads to a ring shape of the wavelength-angular spectrum, suggesting a new type of spatiotemporal coherence and entanglement of photon pairs. By imposing a phase varying in a specific way in both angle and wavelength, one can obtain an interesting state of an entangled photon pair, with the two photons being never at the same point at the same time.

  9. Control of photon correlations in type II parametric down-conversion

    Energy Technology Data Exchange (ETDEWEB)

    Andrews, R [Department of Physics, University of the West Indies, St Augustine (Trinidad and Tobago); Joseph, A T [Department of Physics, University of the West Indies, St Augustine (Trinidad and Tobago); Pike, E R [Department of Physics, King' s College London, Strand, London WC2R 2LS (United Kingdom); Sarkar, Sarben [Department of Physics, King' s College London, Strand, London WC2R 2LS (United Kingdom)

    2005-12-01

    In this paper we describe theoretically quantum control of temporal correlations of entangled photons produced by collinear type II spontaneous parametric down-conversion. We examine the effect of spectral phase modulation of the signal or idler photons arriving at a 50/50 beam splitter on the temporal shape of the entangled-photon wavepacket. The coincidence count rate is calculated analytically for photon pairs in terms of the modulation depth applied to either the signal or idler beam with a spectral phase filter. It is found that the two-photon coincidence rate can be controlled by varying the modulation depth of the spectral filter.

  10. Measurement of precision oscillator phase noise using the two-oscillator coherent down-conversion technique

    Science.gov (United States)

    Pagnanelli, Christopher J.; Cashin, William F.

    1992-01-01

    The characterization of precision frequency standard phase noise and spurious outputs is addressed, using the two-oscillator coherent downconversion technique. Focus is on techniques for making accurate measurements of phase noise and spurious outputs within 100 KHz of a carrier. Significant sources of measurement error related to hardware design problems and inadequate measurement procedures are discussed: measurement errors resulting from system noise sources, phase-locked loop effects, and system bandwidth limitations. In addition, methods and design considerations for minimizing the effects of such errors are presented. Analytic discussions and results are supplemented with actual test data and measurements made using measurement hardware developed at the Ball Corporation, Efratom Division.

  11. Proposal for generating a two-photon added coherent state via down-conversion with a single crystal

    Energy Technology Data Exchange (ETDEWEB)

    Kalamidas, Demetrios [Institute for Ultrafast Spectroscopy and Lasers, City College of the City University of New York, 138th Street and Convent Avenue, New York, NY 10031 (United States); Gerry, Christopher C. [Department of Physics and Astronomy, Lehman College, City University of New York, Bronx, NY 10468-1589 (United States)], E-mail: christopher.gerry@lehman.cuny.edu; Benmoussa, Adil [Department of Physics and Astronomy, Lehman College, City University of New York, Bronx, NY 10468-1589 (United States)

    2008-03-10

    Zavatta et al. [A. Zavatta, S. Viciani, M. Bellini, Science 306 (2004) 660; A. Zavatta, S. Viciani, M. Bellini, Phys. Rev. A 72 (2006) 023820], using parametric down-conversion, have carried out experiments to conditionally generate a single-photon added coherent state. In this Letter, we propose an extension of their method in order to generate the two-photon added coherent state, and point the way toward generating m-photon added coherent states for m>2, all using only one down-conversion crystal.

  12. Effects of a Co-operative Learning Strategy on Ninth-Graders' Understanding of Human Nutrition.

    Science.gov (United States)

    Soyibo, Kola; Evans, Hermel G.

    2002-01-01

    Looks at the effect of teaching strategies on a group's attitude toward biology and understanding human nutrition. Used an experimental group that participated in co-operative learning and a control group taught using the lecture method. Involves ninth graders (n=156) from two high schools in Jamaica. (Author/YDS)

  13. Effects of a Co-operative Learning Strategy on Ninth-Graders' Understanding of Human Nutrition.

    Science.gov (United States)

    Soyibo, Kola; Evans, Hermel G.

    2002-01-01

    Looks at the effect of teaching strategies on a group's attitude toward biology and understanding human nutrition. Used an experimental group that participated in co-operative learning and a control group taught using the lecture method. Involves ninth graders (n=156) from two high schools in Jamaica. (Author/YDS)

  14. Using Peer Teaching to Support Co-Operative Learning in Undergraduate Pharmacology

    Science.gov (United States)

    Depaz, Iris; Moni, Roger W.

    2008-01-01

    We report findings from the second phase of a study of co-operative, group-based assessment in Pharmacology for second-year undergraduates at The University of Queensland, Australia. Students (n = 285) enrolled in the 2006 Bachelor of Science degree program completed a group-based assessment task (weighted 10% of their course). Blended teaching…

  15. Cartalk 2000: development of a co-operative ADAS based on vehicle-to-vehicle communication

    NARCIS (Netherlands)

    Morsink, P.L.J.; Hallouzi, R.; Dagli, I.; Cseh, C.; Schäfers, L.; Nelisse, M.W.; Bruin, D. de

    2003-01-01

    Advanced Driver Assistance Systems (ADAS) benefit from using vehicle-to-vehicle communication. In the 5th framework EC project CarTALK2000 co-operative ADAS are designed, tested and evaluated with respect to increasing traffic safety, efficiency and driving comfort. Communication based longitudinal

  16. Evaluation of bilateral and multilateral defence co-operation and assistance / Najaf Gambarov

    Index Scriptorium Estoniae

    Gambarov, Najaf

    2003-01-01

    Ettekanne Aserbaidžaani sõjalis-poliitilisest koostööst välisriikide relvajõududega ja rahvusvaheliste organisatsioonidega 22.-23. septembrini 2003 Vilniuses toimunud seminaril "South Caucasus: making the best use of external assistance for stability building and for co-operation with NATO"

  17. Evaluation of bilateral and multilateral defence co-operation and assistance / Arthur Aghabekyan

    Index Scriptorium Estoniae

    Aghabekyan, Arthur

    2003-01-01

    Ettekanne Armeenia sõjalis-poliitilisest koostööst välisriikidega ja osalemisest rahvusvahelistes sõjalistes koostööprogrammides 22.-23. septembrini 2003 Vilniuses toimunud seminaril "South Caucasus: making the best use of external assistance for stability building and for co-operation with NATO"

  18. Shariah Governance Framework For Islamic Co-Operatives As An Integral Social Insitution In Malaysia

    Directory of Open Access Journals (Sweden)

    Muhammad Issyam Itam

    2017-01-01

    Full Text Available In Malaysia, Islamic cooperatives are recognized as providers of some form of Islamic financial service similar to Islamic Banks and Takaful Operators. An Islamic Co-operative refers to a co-operative conducting activities and businesses based on Shariah principles. Being a non-banking financial institution, its main objective is to enhance social economic welfare of its members. As a form of captive social institution, it enables the less economically privileged members of society to pool resources as a cooperative. Malaysia is spearheading the Islamic banking and finance industry globally by having in place a proper and well-designed legal and regulatory framework for Islamic Financial Institutions, which includes the area of Shariah governance. However, the Shariah governance framework for the Islamic Co-operative in Malaysia is still in its infancy stage. In this paper, this area will be given focus and properly highlighted. Later, comparison will be made with the Shariah governance framework for the Islamic financial institutions. This paper will conclude that the requirements with regard to Shariah governance for the Islamic Co-operative are flexible and not as strict as required for the Islamic financial institutions.

  19. Introduction of co-operative learning to Grade 4 learners in some ...

    African Journals Online (AJOL)

    Erna Kinsey

    The nature of co-operative learning among Grade 4 learners who, for the first time, were confronted with a task-based ... we accept the working definition of Masithela and Steyn (1999:23), .... space it is not possible to describe all the events.

  20. Members' Preferences for Co-operative Structures: An Experimental Conjoint Study

    NARCIS (Netherlands)

    Kalogeras, N.; Lans, van der I.A.; Pennings, J.M.E.; Dijk, van G.

    2004-01-01

    Abstract As market conditions change rapidly in the 21st century, questions arise concerning how the organizational structures of co-operatives (co-ops) can meet the challenges that these new conditions pose. This paper introduces a framework to structure marketing co-ops (MCs) based on members¿

  1. The VEL and VANLA environmental co-operatives as field laboratories

    NARCIS (Netherlands)

    Stuiver, M.; Ploeg, van der J.D.; Leeuwis, C.

    2003-01-01

    This article describes the Nutrient Management Project of the environmental co-operatives VEL and VANLA as a field laboratory. A field laboratory is defined as a heterogeneous collection of inter-linked scientific studies performed by several actors within a specific field, but – as in normal labora

  2. Microcredit management in Ghana : development of co-operative credit unions among the Dagaaba

    NARCIS (Netherlands)

    Gheneti, Yeshanew

    2007-01-01

    "This thesis focuses on the historical development, the organizational management and the role of credit unions among the Dagaaba in the Upper West Region of Ghana. Co-operative credit unions are well-established financial institutions, with a capacity to mobilize local savings and provide microcred

  3. Jamming Transition of Point-To Traffic Through Co-Operative Mechanisms

    Science.gov (United States)

    Fang, Jun; Qin, Zheng; Chen, Xiqun; Xu, Zhaohui

    2012-11-01

    We study the jamming transition of two-dimensional point-to-point traffic through co-operative mechanisms (DCM) using computer simulation. We propose two decentralized co-operative mechanisms CM which are incorporated into the point-to-point traffic models: stepping aside (CM-SA) and choosing alternative routes (CM-CAR). Incorporating CM-SA is to prevent a type of ping-pong jumps from happening when two objects standing face-to-face want to move in opposite directions. Incorporating CM-CAR is to handle the conflict when more than one object competes for the same point in parallel update. We investigate and compare four models mainly from fundamental diagrams, jam patterns and the distribution of co-operation probability. It is found that although it decreases the average velocity a little, the CM-SA increases the critical density and the average flow. Despite increasing the average velocity, the CM-CAR decreases the average flow by creating substantially vacant areas inside jam clusters. We investigate the jam patterns of four models carefully and explain this result qualitatively. In addition, we discuss the advantage and applicability of decentralized co-operation modeling.

  4. [SUPPORT, CO-OPERATIVE EDUCATION PROGRAMMES, PRAGMATIC CODE OF ETHICS: A CLINICAL APPROACH OF EXECUTIVE TRAINING].

    Science.gov (United States)

    Cabaret, Véronique

    2016-01-01

    This article aims at introducing an educational sequence completed at l'Institut de Formation des Cadres de Santé (IFCS) at the CHRU in Lille in France, entitled "training project and educational project" present in the "training duties" module whose goal is to generate students'knowledge through co-operative education programmes. By creating this innovative sequence, the educational aim is to use the Institut ground as a ground of learning, associated with the various internship grounds, in order to get the most of co-operative education programmes. Besides, in a pragmatic code of ethics in training, the teaching staff draw their inspiration from a clinical approach of executive training: they regard students as true protagonists in a co-operative plan created for them, wishing to design it with them using their words. Thus, students are brought to criticize the IFCS educational project and debate it with the trainers who have built it. Each partner tries to understand the Other, being aware of their being different. By contributing every year to rewriting the educational project which directly concerns them, students build their professional positions as health executives. They play an active role in co-operative education programmes just like IFCS outside partners.

  5. Using Peer Teaching to Support Co-Operative Learning in Undergraduate Pharmacology

    Science.gov (United States)

    Depaz, Iris; Moni, Roger W.

    2008-01-01

    We report findings from the second phase of a study of co-operative, group-based assessment in Pharmacology for second-year undergraduates at The University of Queensland, Australia. Students (n = 285) enrolled in the 2006 Bachelor of Science degree program completed a group-based assessment task (weighted 10% of their course). Blended teaching…

  6. Environmental Engineering Education (E3) in the Gulf Co-Operation Countries

    Science.gov (United States)

    Jassim, Majeed; Coskuner, Gulnur

    2007-01-01

    The six members of the Gulf Co-operation Countries (GCC)--Bahrain, Kuwait, Oman, Qatar, Saudi Arabia and the United Arab Emirates--are facing enormous environmental challenges associated with rapid urbanisation and industrialisation, especially in the last three decades, due to its role as a global hydrocarbon energy centre. None of these…

  7. Evaluation of bilateral and multilateral defence co-operation and assistance / Najaf Gambarov

    Index Scriptorium Estoniae

    Gambarov, Najaf

    2003-01-01

    Ettekanne Aserbaidžaani sõjalis-poliitilisest koostööst välisriikide relvajõududega ja rahvusvaheliste organisatsioonidega 22.-23. septembrini 2003 Vilniuses toimunud seminaril "South Caucasus: making the best use of external assistance for stability building and for co-operation with NATO"

  8. Evaluation of bilateral and multilateral defence co-operation and assistance / Arthur Aghabekyan

    Index Scriptorium Estoniae

    Aghabekyan, Arthur

    2003-01-01

    Ettekanne Armeenia sõjalis-poliitilisest koostööst välisriikidega ja osalemisest rahvusvahelistes sõjalistes koostööprogrammides 22.-23. septembrini 2003 Vilniuses toimunud seminaril "South Caucasus: making the best use of external assistance for stability building and for co-operation with NATO"

  9. A mixture of "cheats" and "co-operators" can enable maximal group benefit.

    Directory of Open Access Journals (Sweden)

    R Craig MaClean

    Full Text Available Is a group best off if everyone co-operates? Theory often considers this to be so (e.g. the "conspiracy of doves", this understanding underpinning social and economic policy. We observe, however, that after competition between "cheat" and "co-operator" strains of yeast, population fitness is maximized under co-existence. To address whether this might just be a peculiarity of our experimental system or a result with broader applicability, we assemble, benchmark, dissect, and test a systems model. This reveals the conditions necessary to recover the unexpected result. These are 3-fold: (a that resources are used inefficiently when they are abundant, (b that the amount of co-operation needed cannot be accurately assessed, and (c the population is structured, such that co-operators receive more of the resource than the cheats. Relaxing any of the assumptions can lead to population fitness being maximized when cheats are absent, which we experimentally demonstrate. These three conditions will often be relevant, and hence in order to understand the trajectory of social interactions, understanding the dynamics of the efficiency of resource utilization and accuracy of information will be necessary.

  10. Evaluation of Georgian military co-operation with partner countries and institutions / George Manjgaladze

    Index Scriptorium Estoniae

    Manjgaladze, George

    2003-01-01

    Ettekanne Gruusia sõjalis-poliitilisest koostööst välisriikide relvajõudude ja rahvusvaheliste organisatsioonidega, sh NATO-ga 22.-23. septembrini 2003 Vilniuses toimunud seminaril "South Caucasus: making the best use of external assistance for stability building and for co-operation with NATO"

  11. Beyond Public and Private: A Framework for Co-operative Higher Education

    Directory of Open Access Journals (Sweden)

    Mike Neary

    2017-07-01

    Full Text Available Universities in the UK are increasingly adopting corporate governance structures, a consumerist model of teaching and learning, and have the most expensive tuition fees in the world (McGettigan, 2013; OECD, 2015. This article discusses collaborative research that aimed to develop and define a conceptual framework of knowledge production grounded in co-operative values and principles. The main findings are outlined relating to the key themes of our research: knowledge, democracy, bureaucracy, livelihood, and solidarity. We consider how these five ‘catalytic principles’ relate to three identified routes to co-operative higher education (conversion, dissolution, or creation and argue that such work must be grounded in an adequate critique of labour and property, i.e. the capital relation. We identify both the possible opportunities that the latest higher education reform in the UK affords the co-operative movement as well as the issues that arise from a more marketised and financialised approach to the production of knowledge (HEFCE, 2015. Finally, we suggest ways that the co-operative movement might respond with democratic alternatives that go beyond the distinction of public and private education.

  12. Evaluation of Georgian military co-operation with partner countries and institutions / George Manjgaladze

    Index Scriptorium Estoniae

    Manjgaladze, George

    2003-01-01

    Ettekanne Gruusia sõjalis-poliitilisest koostööst välisriikide relvajõudude ja rahvusvaheliste organisatsioonidega, sh NATO-ga 22.-23. septembrini 2003 Vilniuses toimunud seminaril "South Caucasus: making the best use of external assistance for stability building and for co-operation with NATO"

  13. Missing--The People's Voice: Organisation for Economic Co-Operation and Development

    Science.gov (United States)

    Pike, Patricia

    2014-01-01

    Sustainable development in education for future economic growth has always been a global focal point for non-governmental agencies across the world. This article highlights the extensive work the Organisation for Economic Co-operation Development (OECD) has achieved over time, constructing contemporary society as we know it today, continually…

  14. Financial Instruments and Conflicts of Interest: Application to French Agricultural Co-operatives

    Directory of Open Access Journals (Sweden)

    Francis Declerck

    2015-11-01

    Agricultural co-operatives' governance and economic projects are often misunderstood by external financial investors. The risk of conflicts of interest plays a role in these misunderstandings in the way retained earnings, returns to agricultural products brought by co-op member and returns to equity capital. Such risks are identified and answers are proposed.

  15. Co-operative learning and adaptive instruction in a mathematics curriculum

    NARCIS (Netherlands)

    Terwel, J.; Herfs, P.G.P.; Mertens, E.H.M.; Perrenet, J.Chr.

    1994-01-01

    The AGO 12 to 16 Project (the acronym AGO stands for the Dutch equivalent of 'Adaptive Instruction and Co-operative Learning') seeks to develop and evaluate a mathematics curriculum which is suitable for mixed-ability groups in secondary education. The research questions we will address here are, fi

  16. Luminescence techniques: Instrumentation and methods

    DEFF Research Database (Denmark)

    Bøtter-Jensen, L.

    1997-01-01

    This paper describes techniques, instruments and methods used in luminescence dating and environmental dosimetry in many laboratories around the world. These techniques are based on two phenomena - thermally stimulated luminescence and optically stimulated luminescence. The most commonly used...... luminescence stimulation and detection techniques are reviewed and information is given on recent developments in instrument design and on the stale of the art in luminescence measurements and analysis. (C) 1998 Elsevier Science Ltd. All rights reserved....

  17. A HYBRID APPROACH FOR NODE CO-OPERATION BASED CLUSTERING IN MOBILE AD HOC NETWORKS

    Directory of Open Access Journals (Sweden)

    C. Sathiyakumar

    2013-01-01

    Full Text Available A Mobile Ad-Hoc Network (MANET is termed as a set of wireless nodes which could be built with infrastructure less environment where network services are afforded by the nodes themselves. In such a situation, if a node refuses to co-operate with other nodes, then it will lead to a considerable diminution in throughput and the network operation decreases to low optimum value. Mobile Ad hoc Networks (MANETs rely on the collaboration of nodes for packet routing ahead. Nevertheless, much of the existing work in MANETs imagines that mobile nodes (probably possessed by selfish users will pursue prearranged protocols without variation. Therefore, implementing the co-operation between the nodes turn out to be an significant issue. The previous work described a secured key model for ad hoc network with efficient node clustering based on reputation and ranking model. But the downside is that the co-operation with the nodes is less results in a communication error. To enhance the security in MANET, in this work, we present a hybrid approach, build a node co-operation among the nodes in MANET by evaluating the weightage of cooperativeness of each node in MANET. With the estimation of normal co-operative nodes, nodes are restructured on its own (self. Then clustering is made with the reorganized nodes to form a secured communication among the nodes in the MANET environment. The Simulation of the proposed Hybrid Approach for Node Cooperation based Clustering (HANCC work is done for varying topology, node size, attack type and intensity with different pause time settings and the performance evaluations are carried over in terms of node cooperativeness, clustering efficiency, communication overhead and compared with an existing secured key model. Compared to an existing secured key model, the proposed HANCC performance is 80-90% high.

  18. Understanding mechanisms of enzyme co-operativity: The importance of not being at equilibrium

    Directory of Open Access Journals (Sweden)

    María Luz Cárdenas

    2015-03-01

    Full Text Available The discovery at the end of the 1950s and the beginning of the 1960s that there were enzymes like threonine deaminase and aspartate transcarbamoylase that failed to follow the expected hyperbolic behaviour predicted by the Michaelis–Menten equation, raised several questions and induced the development of mechanisms to explain this peculiar behaviour. At that time it was already known that the binding of oxygen to haemoglobin did not follow a hyperbolic curve, but a sigmoidal one, and it was thought that a similar situation probably existed for enzymes with sigmoidal kinetics. In other words, the observed kinetic behaviour was a consequence of co-operativity in the substrate binding. Two main models were postulated: those of Monod, Wyman and Changeux in 1965 and of Koshland, Némethy and Filmer in 1966. Both consider that the different conformations are in equilibrium and that there is a rapid equilibrium in the binding, which implies that co-operativity could only exist if there is more than one substrate binding site per enzyme molecule, that is, if the enzyme is an oligomer. What about monomeric enzymes, could they show kinetic co-operativity? Yes, but only through mechanisms that imply the existence of enzyme conformations that are not in equilibrium, and have different kinetic parameters. There are, in fact, very few examples of monomeric enzymes showing kinetic co-operativity with a natural substrate. The case of “glucokinase” (hexokinase D or hexokinase IV, a monomeric enzyme with co-operativity with respect to glucose, will be discussed.

  19. Development of digital sideband separating down-conversion for Yuan-Tseh Lee Array

    Science.gov (United States)

    Li, Chao-Te; Kubo, Derek; Cheng, Jen-Chieh; Kuroda, John; Srinivasan, Ranjani; Ho, Solomon; Guzzino, Kim; Chen, Ming-Tang

    2016-07-01

    This report presents a down-conversion method involving digital sideband separation for the Yuan-Tseh Lee Array (YTLA) to double the processing bandwidth. The receiver consists of a MMIC HEMT LNA front end operating at a wavelength of 3 mm, and sub-harmonic mixers that output signals at intermediate frequencies (IFs) of 2-18 GHz. The sideband separation scheme involves an analog 90° hybrid followed by two mixers that provide down-conversion of the IF signal to a pair of in-phase (I) and quadrature (Q) signals in baseband. The I and Q baseband signals are digitized using 5 Giga sample per second (Gsps) analog-to-digital converters (ADCs). A second hybrid is digitally implemented using field-programmable gate arrays (FPGAs) to produce two sidebands, each with a bandwidth of 1.6 GHz. The 2 x 1.6 GHz band can be tuned to cover any 3.6 GHz window within the aforementioned IF range of the array. Sideband rejection ratios (SRRs) above 20 dB can be obtained across the 3.6 GHz bandwidth by equalizing the power and delay between the I and Q baseband signals. Furthermore, SRRs above 30 dB can be achieved when calibration is applied.

  20. Observation of elliptical rings in Type-I spontaneous parametric down-conversion

    CERN Document Server

    Guilbert, Hannah E; Gauthier, Daniel J

    2015-01-01

    We investigate the transverse spatial profile of down-converted light produced by noncollinear, degenerate, Type-I spontaneous parametric down-conversion in two types of nonlinear crystals. We find that the pattern produced by one crystal, beta barium borate (BBO), produces a circular down-conversion pattern while the other crystal, bismuth triborate (BiBO) produces an elliptical pattern. We show this difference is due to the angle-independent refractive index experienced by the daughter photons in BBO, while they experience an angle-dependent refractive index in BiBO. We image the transverse spatial profile of the generated light to determine the eccentricity produced by each crystal and develop a model to explain our observation. Among other things, this model predicts that there is a wavelength for which the eccentricity from BiBO is nearly zero. Finally, we discuss how the elliptical ring pattern produced in BiBO potentially affects polarization entanglement for experimental setups that collect biphotons ...

  1. Folded down-conversion mixer for a 60 GHz receiver architecture in 65-nm CMOS technology

    Institute of Scientific and Technical Information of China (English)

    Najam Muhammad AMIN; Zhi-gong WANG‡; Zhi-qun LI

    2014-01-01

    We present the design of a folded down-conversion mixer which is incorporated at the final down-conversion stage of a 60 GHz receiver. The mixer employs an ac-coupled current reuse transconductance stage. It performs well under low supply voltages, and is less sensitive to temperature variations and process spread. The mixer operates at an input radio frequency (RF) band ranging from 10.25 to 13.75 GHz, with a fixed local oscillator (LO) frequency of 12 GHz, which down-converts the RF band to an intermediate frequency (IF) band ranging from dc to 1.75 GHz. The mixer is designed in a 65 nm low power (LP) CMOS process with an active chip area of only 0.0179 mm2. At a nominal supply voltage of 1.2 V and an IF of 10 MHz, a maximum voltage conversion gain (VCG) of 9.8 dB, a double sideband noise figure (DSB-NF) of 11.6 dB, and a linearity in terms of input 1 dB compression point (Pin,1dB) of−13 dBm are measured. The mixer draws a current of 5 mA from a 1.2 V supply dissipating a power of only 6 mW.

  2. Advanced synchronous luminescence system

    Science.gov (United States)

    Vo-Dinh, Tuan

    1997-01-01

    A method and apparatus for determining the condition of tissue or otherwise making chemical identifications includes exposing the sample to a light source, and using a synchronous luminescence system to produce a spectrum that can be analyzed for tissue condition.

  3. Structured luminescence conversion layer

    Science.gov (United States)

    Berben, Dirk; Antoniadis, Homer; Jermann, Frank; Krummacher, Benjamin Claus; Von Malm, Norwin; Zachau, Martin

    2012-12-11

    An apparatus device such as a light source is disclosed which has an OLED device and a structured luminescence conversion layer deposited on the substrate or transparent electrode of said OLED device and on the exterior of said OLED device. The structured luminescence conversion layer contains regions such as color-changing and non-color-changing regions with particular shapes arranged in a particular pattern.

  4. Digital coherent detection of multi-gigabit 40 GHz carrier frequency radio-over-fibre signals using photonic downconversion

    DEFF Research Database (Denmark)

    Caballero Jambrina, Antonio; Zibar, Darko; Tafur Monroy, Idelfonso

    2010-01-01

    Detection of high-speed radio signals is a challenge for next generation radio-over-fibre links, requiring high bandwidth and linearity in the receiver. By using photonic downconversion in a coherent receiver, detection of high bit-rate 16-QAM signals, up to 4 Gbit/s, at a 40 GHz carrier frequency...

  5. Quantum spatial correlations in high-gain parametric down-conversion measured by means of a CCD camera

    DEFF Research Database (Denmark)

    Jedrkiewicz, O.; Brambilla, E.; Bache, Morten

    2006-01-01

    We consider travelling-wave parametric down-conversion in the high-gain regime and present the experimental demonstration of the quantum character of the spatial fluctuations in the system. In addition to showing the presence of sub-shot noise fluctuations in the intensity difference, we demonstr...

  6. NATO, Libya operations and intelligence co-operation – a step forward?

    DEFF Research Database (Denmark)

    Svendsen, Adam David Morgan

    2011-01-01

    "With the ‘fall’ of Tripoli towards the end of August 2011, it has become increasingly apparent that the intelligence co-operation witnessed in Libya during the NATO campaign performed an increasingly important role in realizing operational and strategic ‘successes’. These recent intelligence...... developments can be opened up for some further analysis, forming the main focus of this article. Ultimately, this article concludes that, over time and albeit while gradual, we have seen what can be regarded as ‘a step forward’ in co-operative intelligence activities in Libya. Although several pressing...... difficulties have been present, and have had various impacts at different junctures of interactivity, the ‘problems’ encountered have not completely overwhelmed either operationally or strategically all of the diverse participants involved in Libya." - Abstract from journal....

  7. Cross-border Co-operation and Policy Networks in West Africa

    DEFF Research Database (Denmark)

    Trémolières, Marie; Walther, Olivier

    policy networks, showing that borders have notable and diverse impacts on exchanges of information and the relative power of networks. The report then analyses a range of regional indicators of co-operation potential, visually demonstrating that borders can also affect the ability of sub-regions within......This publication examines how policy actors involved in cross-border co-operation contribute to the regional integration process in West Africa. It uses a pioneering methodology, known as social network analysis, to visualise the formal and informal relationships between actors involved in cross-border...... West Africa to develop cross-border initiatives in a number of ways. Combining these two analyses with the perceptions of regional policy makers as to which border areas they consider as priorities for regional integration, the publication concludes with the analytical foundations for more effective...

  8. Power corrupts co-operation: cognitive and motivational effects in a double EEG paradigm.

    Science.gov (United States)

    Kanso, Riam; Hewstone, Miles; Hawkins, Erin; Waszczuk, Monika; Nobre, Anna Christina

    2014-02-01

    This study investigated the effect of interpersonal power on co-operative performance. We used a paired electro-encephalogram paradigm: pairs of participants performed an attention task, followed by feedback indicating monetary loss or gain on every trial. Participants were randomly allocated to the power-holder, subordinate or neutral group by creating different levels of control over how a joint monetary reward would be allocated. We found that power was associated with reduced behavioural accuracy. Event-related potential analysis showed that power-holders devoted less motivational resources to their targets than did subordinates or neutrals, but did not differ at the level of early conflict detection. Their feedback potential results showed a greater expectation of rewards but reduced subjective magnitude attributed to losses. Subordinates, on the other hand, were asymmetrically sensitive to power-holders' targets. They expected fewer rewards, but attributed greater significance to losses. Our study shows that power corrupts balanced co-operation with subordinates.

  9. Cross-Border Governance: Balancing Formalized and Less Formalized Co-Operations

    Directory of Open Access Journals (Sweden)

    Kristina Zumbusch

    2015-07-01

    Full Text Available The paper analyses cross-border co-operation with regard to its degree of formalization. Herewith, the focus is not on single cross-border organizations, but on the encompassing governance systems in the respective regions. That means that the specific combination of differently organized cross-border arrangements is analyzed. Cross-border governance systems are facing multiple governance challenges which ask either for a certain degree of institutionalization or for more informal solutions. Based on an empirical comparison of the two experienced, but differently organized, cross-border regions in Europe the Lake Constance Region and the Upper-Rhine Region, the paper illustrates that the organizational variation of cross-border governance systems show specific patterns. From these findings, first arguments are deduced for balancing formalized and more informal co-operations in cross-border governance systems.

  10. Enhanced 1G 4 emission in NaLaF 4: Pr 3+, Yb 3+ and charge transfer in NaLaF 4: Ce 3+, Yb 3+ studied by fourier transform luminescence spectroscopy

    Science.gov (United States)

    van der Kolk, E.; Ten Kate, O. M.; Wiegman, J. W.; Biner, D.; Krämer, K. W.

    2011-05-01

    A high resolution luminescence study of NaLaF 4: 1%Pr 3+, 5%Yb 3+ and NaLaF 4: 1%Ce 3+, 5%Yb 3+ in the UV to NIR spectral range using a InGaAs detector and a fourier transform interferometer is reported. Although the Pr 3+( 3P 0 → 1G 4), Yb 3+( 2F 7/2 → 2F 5/2) energy transfer step takes place, significant Pr 3+1G 4 emission around 993, 1330 and 1850 nm is observed. No experimental proof for the second energy transfer step in the down-conversion process between Pr 3+ and Yb 3+ can be given. In the case of NaLaF 4: Ce 3+, Yb 3+ it is concluded that the observed Yb 3+ emission upon Ce 3+ 5d excitation is the result of a charge transfer process instead of down-conversion.

  11. Some like to join, others to deliver. An econometric analysis of farmers’ relationships with agricultural co-operatives

    NARCIS (Netherlands)

    Gardebroek, C.; Pascucci, S.

    2010-01-01

    In many European countries, farmers are a member of a processing or marketing co-operative, and most of these farmers also deliver their products to that co-operative. However, an extensive dataset of Italian farmers shows that not all members deliver to their co-op, and that there are also non-memb

  12. Institutional and scientific co-operation, networking and capacity building in the field of food safety and quality

    NARCIS (Netherlands)

    Boekel, van M.A.J.S.; Meerdink, G.; Banati, D.; Marvin, H.J.P.; Kuiper, H.A.; Houtman, C.B.

    2002-01-01

    This paper explains the situation in Hungary and The Netherlands regarding scientific co-operation, networking and capacity building in the field of food quality and safety. Specific details are given about institutional co-operation including exchanges between staff and students, collaborative proj

  13. Reactions of Spanish Agricultural Co-operatives to Collective Globalization: Ideal Discourse Types

    OpenAIRE

    Entrena Durán, Francisco; Moyano Estrada, Eduardo

    2005-01-01

    The main objective of this article is to build up a typology of the ideological discourses which guide and legitimize the different, and often mutually contradictory, reactions of Spanish agricultural co-operatives to the process of ever-increasing socio-economical globalization in which they are immersed. In accordance with this typology, in which we have followed a criterion similar to Max Weber's, we distinguish four ideal ideological discourse types. These go along a continuum from those ...

  14. Civil-military relations and co-operation in Kosovo 1999 to 2001

    OpenAIRE

    2003-01-01

    Co-operation between civil society actors and military personnel is increasingly common in humanitarian missions since the early 1990s. However the interaction has led to varying degrees of friction between both groups, at times lessening the coordination and efficiency of the civil-military relationship. Existing theories of civilmilitary relations are largely based upon the relationship between the military and their civilian government, and have not been tested within the relationships exp...

  15. A novel model for extending international co-operation in science and education

    Institute of Scientific and Technical Information of China (English)

    DE BOER Sirp J.; QIU Ji-zhen(邱济真)

    2004-01-01

    In September 1994 the University of Twente, the Netherlands, and Zhejiang University, China, decided to cooperate in the field of science, education and management. After several visits of delegations from both sides it was considered worthwhile to explore further opportunities for mutual cooperation. The directors of international cooperation on each side jointly commissioned a project to investigate the potential in a systematic way and to establish further contacts where appropriate. This paper reports on the results of the research cum matching project.To reveal promising matches between multiple departments of both academic institutions a matching model for universities was designed. The study was carried out along two parallel lines. In the research line the theoretical framework was developed into a model for international university co-operation. Moreover, an analysis was carried out on internal, external and cultural aspects resulting in a set of thirty four influencing factors.In the matching line a total of seventy interviews were held in order to identify promising matches between units at both universities. This line resulted in eleven promising matches for further co-operation.The novel model appeared useful in analyzing the variety of factors and in developing matches between both universities. In the further implementation of the model the issues of "level of co-operation" and "top-down versus bottom-up" need to be addressed in more detail.

  16. Co-operative versus independent transport of different cargoes by Kinesin-1.

    Science.gov (United States)

    Hammond, Jennetta W; Griffin, Kelly; Jih, Gloria T; Stuckey, Jeanne; Verhey, Kristen J

    2008-05-01

    Kinesin motors drive the intracellular transport of multiple cargoes along microtubule tracks; yet, how kinesins discriminate among their many potential cargoes is unknown. We tested whether Kinesin-1 cargoes compete, co-operate or are transported independently of each other. We focused on Kinesin-1 cargoes that bind directly to the kinesin light chain (KLC) subunit, namely the c-Jun NH(2)-terminal kinase-interacting proteins (JIPs) 1 and 3, Kidins220/ARMS and PAT1. Overexpression of individual cargo proteins in differentiated CAD cells resulted in mislocalization of the endogenous protein but had no effect on localization of other cargo proteins to neurite tips. Thus, while transport of distinct cargoes is saturable, they do not compete with each other. Interestingly, we found that low expression of JIP1 or JIP3 enhanced the transport of the other JIP to neurite tips. Moreover, JIP1 and JIP3 require each other for transport. Co-operative transport is due to an interaction between JIP1 and JIP3 as well as distinct binding sites on the KLC tetratricopeptide repeat (TPR) bundle: the TPR groove binds to C-terminal residues of JIP1, whereas the TPR surface binds to internal residues in JIP3. Formation of a JIP1/JIP3/KLC complex is necessary for efficient JIP1 or JIP3 transport in neuronal cells. Thus, JIP scaffolding proteins are transported in a co-operative manner, despite the independent transport of other Kinesin-1 cargoes.

  17. Down conversion luminescence behavior of Er and Yb doped Y2O3 phosphor

    Directory of Open Access Journals (Sweden)

    Sadhana Agrawal

    2014-10-01

    Full Text Available We have studied downconversion luminescence behaviour of Y2O3 phosphor doped with Er 1 mol% and 1 mol% of Yb. The sample was prepared by modified solid state reaction method. Using inorganic material like (Y2O3, Flux Calcium Fluoride (CaF2 and Er2O3 as well as Yb2O3 with molar ratio 1 mol% of dopant. The prepared phosphor sample was characterized using Powder X-Ray Diffraction (PXRD, Field Emission Gun Scanning Electron Microscopy (FEGSEM, High Resolution Transmission Electron Microscopy (HRTEM, Photoluminescence (PL, Thermoluminescence (TL and CIE techniques. The obtained sample shows an intense greenish-white emission (ranging from 350 to 600 nm, centered at 565 nm under a wide range of UV light excitation (220–400 nm.

  18. Hydrothermal synthesis, characterization and luminescent properties of lanthanide-doped NaLaF$_4$ nanoparticles

    Indian Academy of Sciences (India)

    JIGMET LADOL; HEENA KHAJURIA; SONIKA KHAJURIA; HAQ NAWAZ SHEIKH

    2016-08-01

    Nanoparticles of sodium lanthanum (III) fluoride-doped and co-doped with Eu$^{3+}/Tb$^{3+}$ were prepared by the hydrothermal method using citric acid as structure-directing agent. Structural aspects and optical properties of synthesized nanoparticles were studied by powder X-ray diffraction (XRPD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), selected area electron diffraction (SAED), energy-dispersive X-ray spectra (EDS), particle size by dynamic light scattering (DLS), Fourier transform infrared (FTIR) spectrum and photoluminescence (PL) techniques. Nanoparticles consist of well-crystallized hexagonal phase and the average crystallite size for undoped and doped-NaLaF$_4$ nanoparticles are in the range of 20–22 nm. TEM images show that nanoparticles have cylindrical shape and crystalline nature of nanoparticles was confirmed by SAED patterns. Downconversion(DC) luminescent properties of doped NaLaF4 were also investigated and impact of co-doping has been explored.

  19. Enhancing Heralding Efficiency and Biphoton Rate in Type-I Spontaneous Parametric Down-Conversion

    CERN Document Server

    Guilbert, Hannah E

    2014-01-01

    The nonlinear optical process of spontaneous parametric down-conversion (SPDC) is widely studied for applications in quantum information science due to its ability to produce two photons that can be entangled in many degrees of freedom. For applications in quantum communication, two metrics of this process are particularly important: heralding efficiency and total joint rate. Here, we derive expressions for both quantities for a variety of different beam geometries and frequencies. We pay specific attention to the spectrum of both biphotons and individual photons. We reveal the underlying mechanisms responsible for the spectral shape and show they differ for different geometries and frequencies. We then use these spectra to calculate heralding efficiency and joint count rate and examine how each of these metrics changes with different geometries, frequencies, and spectral filtering and beam parameters. Interestingly, we find very high heralding efficiencies are achievable for collinear geometries, while nonco...

  20. Lattice topology and spontaneous parametric down-conversion in quadratic nonlinear waveguide arrays

    CERN Document Server

    Leykam, Daniel; Sukhorukov, Andrey A; Desyatnikov, Anton S

    2015-01-01

    We analyze spontaneous parametric down-conversion in various experimentally feasible 1D quadratic nonlinear waveguide arrays, with emphasis on the relationship between the lattice's topological invariants and the biphoton correlations. Nontrivial topology results in a nontrivial "winding" of the array's Bloch waves, which introduces additional selection rules for the generation of biphotons. These selection rules are in addition to, and independent of existing control using the pump beam's spatial profile and phase matching conditions. In finite lattices, nontrivial topology produces single photon edge modes, resulting in "hybrid" biphoton edge modes, with one photon localized at the edge and the other propagating into the bulk. When the single photon band gap is sufficiently large, these hybrid biphoton modes reside in a band gap of the bulk biphoton Bloch wave spectrum. Numerical simulations support our analytical results.

  1. Lattice topology and spontaneous parametric down-conversion in quadratic nonlinear waveguide arrays

    Science.gov (United States)

    Leykam, Daniel; Solntsev, Alexander S.; Sukhorukov, Andrey A.; Desyatnikov, Anton S.

    2015-09-01

    We analyze spontaneous parametric down-conversion in various experimentally feasible one-dimensional quadratic nonlinear waveguide arrays, with emphasis on the relationship between the lattice's topological invariants and the biphoton correlations. Nontrivial topology results in a nontrivial "winding" of the array's Bloch waves, which introduces additional selection rules for the generation of biphotons, independent of existing control using the pump beam's spatial profile and phase-matching conditions. In finite lattices, nontrivial topology produces single-photon edge modes, resulting in "hybrid" biphoton edge modes, with one photon localized at the edge and the other propagating into the bulk. When the single-photon band gap is sufficiently large, these hybrid biphoton modes reside in a band gap of the bulk biphoton Bloch wave spectrum. Numerical simulations support our analytical results.

  2. Antireflective downconversion ZnO:Er3+,Yb3+ thin film for Si solar cell applications

    Science.gov (United States)

    Elleuch, R.; Salhi, R.; Deschanvres, J.-L.; Maalej, R.

    2015-02-01

    Hexagonal wurtzite phased ZnO:Er3+/Yb3+ thin films with various Yb concentrations were deposited on Si(111) substrate by Aerosol Assisted Chemical Vapor Deposition process. Post-annealed films at 1000 °C in air atmosphere showed a crystallinity enhancement. Yb3+ (4F7/2 → 4F5/2) 1000 nm emission increased with the increase of Yb3+ concentration emanating from an Er-Yb energy transfer. The reflectance percentage of 12% was achieved in the [250-1000 nm] range, and the refractive index of 1.97 was obtained for 632 nm wavelength. These results suggest that the (3 mol. % Er, 9 mol. % Yb) codoped film is a highly efficient antireflective downconversion layer for enhancing Si solar cell efficiency.

  3. High-Fidelity Down-Conversion Source for Secure Communications Using On-Demand Single Photons

    Science.gov (United States)

    Roberts, Tony

    2015-01-01

    AdvR, Inc., has built an efficient, fully integrated, waveguide-based source of spectrally uncorrelated photon pairs that will accelerate research and development (R&D) in the emerging field of quantum information science. Key to the innovation is the use of submicron periodically poled waveguides to produce counter propagating photon pairs, which is enabled by AdvR's patented segmented microelectrode poling technique. This novel device will provide a high brightness source of down-conversion pairs with enhanced spectral properties and low attenuation, and it will operate in the visible to the mid-infrared spectral region. A waveguide-based source of spectrally and spatially pure heralded photons will contribute to a wide range of NASA's advanced technology development efforts, including on-demand single photon sources for high-rate spaced-based secure communications.

  4. Parameter Estimation with Entangled Photons Produced by Parametric Down-Conversion

    Science.gov (United States)

    Cable, Hugo; Durkin, Gabriel A.

    2010-01-01

    We explore the advantages offered by twin light beams produced in parametric down-conversion for precision measurement. The symmetry of these bipartite quantum states, even under losses, suggests that monitoring correlations between the divergent beams permits a high-precision inference of any symmetry-breaking effect, e.g., fiber birefringence. We show that the quantity of entanglement is not the key feature for such an instrument. In a lossless setting, scaling of precision at the ultimate "Heisenberg" limit is possible with photon counting alone. Even as photon losses approach 100% the precision is shot-noise limited, and we identify the crossover point between quantum and classical precision as a function of detected flux. The predicted hypersensitivity is demonstrated with a Bayesian simulation.

  5. A TR-UWB Downconversion Autocorrelation Receiver for Wireless Body Area Network

    Directory of Open Access Journals (Sweden)

    Islam SMRiazul

    2009-01-01

    Full Text Available Low power UWB receiver architecture is proposed for a Wireless Body Area Network (WBAN. This receiving technology is a synergy of existing downconversion-based narrowband rejection mechanism in RF front end and signal processing in frequency domain. Frequency components of converted and filtered UWB pulses are separated into real and imaginary parts, independently correlated and effectively combined to achieve an improved output Signal to noise ratio (SNR. An extensive mathematical analysis has been performed to formulate the close-form expressions for SNRs in order to compare system performances toward favorable BER under BPSK modulation scheme. Analysis shows that optimal rotation of coordination plays an important role for the enhancement of receiving SNR which is further confirmed by computer simulation. A wide range of link level simulation (LLS urges that the proposed system is more power efficient in higher-order modulation (HOM schemes. Transmitted Reference (TR scheme has been considered as the basis for wideband communication.

  6. Entanglement, coherence, and redistribution of quantum resources in double spontaneous down-conversion processes

    Science.gov (United States)

    Bruschi, David Edward; Sabín, Carlos; Paraoanu, Gheorghe Sorin

    2017-06-01

    We study the properties of bisqueezed tripartite Gaussian states created by two spontaneous parametric down-conversion processes that share a common idler. We give a complete description of the quantum correlations across all partitions, as well as of the genuine multipartite entanglement, obtaining analytical expressions for most of the quantities of interest. We find that the state contains genuine tripartite entanglement, in addition to the bipartite entanglement among the modes that are directly squeezed. We also investigate the effect of homodyne detection of the photons in the common idler mode, and analyze the final reduced state of the remaining two signal modes. We find that this measurement leads to a conversion of the coherence of the two signal modes into entanglement, a phenomenon that can be regarded as a redistribution of quantum resources between the modes. The applications of these results to quantum optics and circuit quantum electrodynamics platforms are also discussed.

  7. Parameter estimation with entangled photons produced by parametric down-conversion.

    Science.gov (United States)

    Cable, Hugo; Durkin, Gabriel A

    2010-07-01

    We explore the advantages offered by twin light beams produced in parametric down-conversion for precision measurement. The symmetry of these bipartite quantum states, even under losses, suggests that monitoring correlations between the divergent beams permits a high-precision inference of any symmetry-breaking effect, e.g., fiber birefringence. We show that the quantity of entanglement is not the key feature for such an instrument. In a lossless setting, scaling of precision at the ultimate "Heisenberg" limit is possible with photon counting alone. Even as photon losses approach 100% the precision is shot-noise limited, and we identify the crossover point between quantum and classical precision as a function of detected flux. The predicted hypersensitivity is demonstrated with a Bayesian simulation.

  8. Optical down-conversion in doped ZnSe:Tb3+ nanocrystals.

    Science.gov (United States)

    Das, Sandip; Mandal, Krishna C

    2013-02-07

    Rare earth (RE) Tb(3+)-doped high quality ZnSe nanocrystals (NCs) were synthesized by a facile chemical hot-injection method. ZnSe:Tb(3+) nanocrystals exhibited broadband absorption below the first excitonic absorption peak. Photoluminescence spectra showed Tb(3+) emission lines in the visible spectral window at room temperature when excited by UV radiation below the band-edge of the host ZnSe nanocrystals. Our experimental results indicate optical down-conversion in these Tb(3+)-doped Zn-chalcogenide nanocrystals via energy migration from host ZnSe to the Tb(3+) dopant. The host-dopant energy transfer mechanism for this ZnSe:Tb(3+) nanocrystal system is correlated with the emission spectra.

  9. Efficient ultraviolet-blue to near-infrared downconversion in Bi-Dy-Yb-doped zeolites

    Science.gov (United States)

    Bai, Zhenhua; Fujii, Minoru; Hasegawa, Takashi; Imakita, Kenji; Mizuhata, Minoru; Hayashi, Shinji

    2011-11-01

    Ultraviolet-blue to near-infrared (NIR) downconversion is investigated for the Dy3+-Yb3+ couple in zeolites by steady-state and time-resolved photoluminescence (PL) spectra, and PL excitation spectra. Upon excitation of the 4F9/2 level of Dy3+, NIR quantum cutting could occur through a two-step energy transfer from one Dy3+ ion to two neighbouring Yb3+ ions via an intermediate level. The energy transfer efficiency from the 4F9/2 level is estimated to be 42%, and the intrinsic PL quantum efficiency of Yb3+ emission reaches 54%. The findings may have potential application in enhancing the energy efficiency of silicon-based solar cells.

  10. Parametric down-conversion photon pair source on a nanophotonic chip

    CERN Document Server

    Guo, Xiang; Schuck, Carsten; Jung, Hojoong; Cheng, Risheng; Tang, Hong X

    2016-01-01

    Quantum photonic chips, which integrate quantum light sources alongside active and passive optical elements, as well as single photon detectors, show great potential for photonic quantum information processing and quantum technology. Mature semiconductor nanofabrication processes allow for scaling such photonic integrated circuits to on-chip networks of increasing complexity. Second order nonlinear materials are the method of choice for generating photonic quantum states in the overwhelming part of linear optic experiments using bulk components but integration with waveguide circuitry on a nanophotonic chip proved to be challenging. Here we demonstrate such an on-chip parametric down-conversion source of photon pairs based on second order nonlinearity in an Aluminum nitride microring resonator. We show the potential of our source for quantum information processing by measuring high-visibility antibunching of heralded single photons with nearly ideal state purity. Our down conversion source operates with high ...

  11. Linear-in-dB Variable-Gain Downconversion Mixer for Zero Intermediate Frequency Receivers

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    In-phase/quadrature (I/Q) mismatch is a key problem in zero intermediate frequency (ZIF) receiver architectures. Although integration and careful layout can alleviate I/Q mismatch, circuit and system level calibrations are also needed due to process variations and variable operating conditions. The amplitude imbalance between I/Q channels was calibrated using a modified R-2R ladder to achieve fine linear-in-dB variable gain. A downconversion mixer working in the 2.4-GHz band was developed for a wireless local area network (WLAN) ZIF receiver using 0.25-μm complementary metal-oxide semiconductor (CMOS). The two-stage mixer configuration relaxes the tradeoff between noise and linearity. Experimental results verify the fine linear-in-dB variable conversion gain of the mixer, which can also be used as part of an automatic gain control (AGC) loop.

  12. Pure down-conversion photons through sub-coherence-length domain engineering

    Science.gov (United States)

    Graffitti, Francesco; Kundys, Dmytro; Reid, Derryck T.; Brańczyk, Agata M.; Fedrizzi, Alessandro

    2017-09-01

    Photonic quantum technology relies on efficient sources of coherent single photons, the ideal carriers of quantum information. Heralded single photons from parametric down-conversion can approximate on-demand single photons to a desired degree, with high spectral purities achieved through group-velocity matching and tailored crystal nonlinearities. Here we propose crystal-nonlinearity-engineering techniques with sub-coherence-length domains. We first introduce a combination of two existing methods: a deterministic approach with coherence-length domains and probabilistic domain-width annealing. We then show how the same deterministic domain-flip approach can be implemented with sub-coherence-length domains. Both of these complementary techniques create highly pure photons, outperforming previous methods, in particular for short nonlinear crystals matched to femtosecond lasers.

  13. Parameter Estimation with Entangled Photons Produced by Parametric Down-Conversion

    Science.gov (United States)

    Cable, Hugo; Durkin, Gabriel A.

    2010-01-01

    We explore the advantages offered by twin light beams produced in parametric down-conversion for precision measurement. The symmetry of these bipartite quantum states, even under losses, suggests that monitoring correlations between the divergent beams permits a high-precision inference of any symmetry-breaking effect, e.g., fiber birefringence. We show that the quantity of entanglement is not the key feature for such an instrument. In a lossless setting, scaling of precision at the ultimate "Heisenberg" limit is possible with photon counting alone. Even as photon losses approach 100% the precision is shot-noise limited, and we identify the crossover point between quantum and classical precision as a function of detected flux. The predicted hypersensitivity is demonstrated with a Bayesian simulation.

  14. Producing high fidelity single photons with optimal brightness via waveguided parametric down-conversion.

    Science.gov (United States)

    Laiho, K; Cassemiro, K N; Silberhorn, Ch

    2009-12-07

    Parametric down-conversion (PDC) offers the possibility to control the fabrication of non-Gaussian states such as Fock states. However, in conventional PDC sources energy and momentum conservation introduce strict frequency and photon number correlations, which impact the fidelity of the prepared state. In our work we optimize the preparation of single-photon Fock states from the emission of waveguided PDC via spectral filtering. We study the effect of correlations via photon number resolving detection and quantum interference. Our measurements show how the reduction of mixedness due to filtering can be evaluated. Interfering the prepared photon with a coherent state we establish an experimentally measured fidelity of the produced target state of 78%.

  15. Luminescence from Porous Silicon

    Directory of Open Access Journals (Sweden)

    A. Gupta

    1998-01-01

    Full Text Available Recent observations of photoluminescene (PL and electroluminescence (EL from poroussilicon (PS have prompted many theoretical and experimental studies. Bulk crystalline Si is anindirect band gap material in which .recombination is dominated by non-radiative processes.Therefore, it cannot be used as light-emitting component in Si circuits. PS is a new material formed byanodisation ofsingle crystal Si wafers in hydro fluoric (liF solution. Luminescence from this materialis being explored for technological applications all over the world. The mechanism of luminescence isstill not well-understood. Several models have been proposed but still the facts about the strong lightemission at room temperature are unknown. This paper presents a review of the fabrication process andstudies on luminescent properties of PS. A hybrid model based on quantum confinement of carriers inthe nanometer size Si crystallites having a large number of surface states is suggested to explain theobserved properties.

  16. Celebrating Co-operation among Saskatchewan’s Libraries: The Multitype Library Board, 1996-2016

    Directory of Open Access Journals (Sweden)

    Michael Shires

    2016-03-01

    Full Text Available Saskatchewan’s Multitype Library Board (MLB celebrates its 20th anniversary in 2016. It was established under the passage of the provincial government’s The Libraries Co- operation Act in 1996 to facilitate the co-operative development of the multitype library system in Saskatchewan. This legislation is unique in Canada. The MLB is a Minister of Education Advisory Board and it provides a forum to promote and facilitate co-operation among over 320 public libraries in 10 provincial systems, 25 post-secondary libraries, 755 school libraries, several special libraries, and other information providers. Major milestones of the MLB include helping to eliminate the Provincial Sales Tax on library subscriptions, establishing a provincial digitization plan, and creating a cross-sector database licensing program that has resulted in a projected value of 14.8 million dollars to Saskatchewan users in 2014. The development of the MLB and the impact of the programs it has initiated will be discussed, and recommendations for developing a collaborative initiative will be provided. Le Multitype Library Board (MLB de Saskatchewan fête son 20e anniversaire en 2016. Il était établi sous l’Acte The Libraries Co-operation du parti Libéral en 1996 pour faciliter le développement coopératif du système de bibliothèque Multitype en Saskatchewan. Cette législation est unique au Canada. Le MLB est un comité consultatif du ministère de l’Éducation et il fournit un forum pour promouvoir et faciliter la coopération entre plus de 320 bibliothèques publiques dans dix systèmes provinciaux, 25 bibliothèques postsecondaires, 755 bibliothèques scolaires, plusieurs bibliothèques spéciales, et d’autres fournisseurs d’informations. Les étapes importantes du MLB comprennent, à aider à éliminer les taxes de vente provinciale sur les abonnements aux bibliothèques, à établir un plan provincial de numérisation, et à créer un programme de licence

  17. Implementing agreement on a co-operative program on inertial fusion energy

    Energy Technology Data Exchange (ETDEWEB)

    Latkowski, J; Hogan, W; Meier, W

    2000-01-04

    The Programme to be carried out by the Contracting Parties within the framework of this Agreement shall consist of co-operative research, development, demonstrations and exchanges of information regarding inertial fusion energy (IFE). This shall include: (1) Nuclear Technology, (2) Fusion Materials, (3) Environment, Safety and Economics, (4) Laser Drivers, (5) Ion Beam Drivers and Beam/Plasma Interactions, (6) Target Production, Injection and Tracking, (7) Fusion Diagnostics, (8) Driver/Plasma Interactions, (9) Fast Ignition and (10) Power Plant Design Studies. Annexes to this agreement will describe specific tasks in each area.

  18. CCD Luminescence Camera

    Science.gov (United States)

    Janesick, James R.; Elliott, Tom

    1987-01-01

    New diagnostic tool used to understand performance and failures of microelectronic devices. Microscope integrated to low-noise charge-coupled-device (CCD) camera to produce new instrument for analyzing performance and failures of microelectronics devices that emit infrared light during operation. CCD camera also used to indentify very clearly parts that have failed where luminescence typically found.

  19. 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 luminescenc

  20. 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

  1. Silicon: electrochemistry and luminescence

    NARCIS (Netherlands)

    Kooij, Ernst Stefan

    2001-01-01

    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 luminescenc

  2. Efficient THZ Source Based on Cascaded Optical Down-Conversion in Orientation-Patterned GaAs Structures

    Science.gov (United States)

    2008-11-20

    structured nonlinear optical materials , GaAs, optical THz generation, cavity-enhanced, nonlinear-optical frequency down-conversion, quasi-phasematched...Many nonlinear optical materials are relatively transparent at THz frequencies below lowest phonon resonance (e.g. at 8 THz for GaAs and 5 THz for... optical materials : both collinear (forward and backward) and noncollinear phase matching was used to generate broadly tunable, 20-190cm-1 (0.6-5.7 THz

  3. Analytical Method for Energy Spectra and Eigenstates in the Process of k-Photon Down-Conversion with Quantized Pump

    Institute of Scientific and Technical Information of China (English)

    Li Jia-Hua; CHEN Ai-Xi; WANG Wen-Yi

    2003-01-01

    In this paper, using the arguments of Wu et al. [Phys. Rev. Lett. 86 (2001) 2200] we analytically discussthe energy spectra and corresponding eigenstates for the process of k-photon down-conversion with quantized pump ina high-Q cavity by the aid of the computer programme. Remarkably, it is also shown that such a method can be usedfor solving numerically the equations in a much simpler manner than the previous ones.

  4. Wigner representation for experiments on quantum cryptography using two-photon polarization entanglement produced in parametric down-conversion

    Energy Technology Data Exchange (ETDEWEB)

    Casado, A [Departamento de Fisica Aplicada III, Escuela Superior de Ingenieros, Universidad de Sevilla, 41092 Sevilla (Spain); Guerra, S [Centro Asociado de la Universidad Nacional de Educacion a Distancia de Las Palmas de Gran Canaria (Spain); Placido, J [Departamento de Fisica, Universidad de Las Palmas de Gran Canaria (Spain)], E-mail: acasado@us.es

    2008-02-28

    In this paper, the theory of parametric down-conversion in the Wigner representation is applied to Ekert's quantum cryptography protocol. We analyse the relation between two-photon entanglement and (non-secure) quantum key distribution within the Wigner framework in the Heisenberg picture. Experiments using two-qubit polarization entanglement generated in nonlinear crystals are analysed in this formalism, along with the effects of eavesdropping attacks in the case of projective measurements.

  5. Power corrupts co-operation: cognitive and motivational effects in a double EEG paradigm

    Science.gov (United States)

    Kanso, Riam; Hewstone, Miles; Hawkins, Erin; Waszczuk, Monika; Nobre, Anna Christina

    2014-01-01

    This study investigated the effect of interpersonal power on co-operative performance. We used a paired electro-encephalogram paradigm: pairs of participants performed an attention task, followed by feedback indicating monetary loss or gain on every trial. Participants were randomly allocated to the power-holder, subordinate or neutral group by creating different levels of control over how a joint monetary reward would be allocated. We found that power was associated with reduced behavioural accuracy. Event-related potential analysis showed that power-holders devoted less motivational resources to their targets than did subordinates or neutrals, but did not differ at the level of early conflict detection. Their feedback potential results showed a greater expectation of rewards but reduced subjective magnitude attributed to losses. Subordinates, on the other hand, were asymmetrically sensitive to power-holders’ targets. They expected fewer rewards, but attributed greater significance to losses. Our study shows that power corrupts balanced co-operation with subordinates. PMID:23160813

  6. Co-operation and conflict in a hospital: interprofessional differences in perception and management of conflicts.

    Science.gov (United States)

    Skjørshammer, M

    2001-02-01

    This article presents a case study of a Norwegian hospital, analysing how health professionals manage conflicts related to work co-operation. Altogether, 29 health professionals working in the hospital were interviewed, and data was analysed according to a grounded theory approach. When in conflict, health professionals seem to use three major approaches to handling the situation: avoidance, forcing and negotiation, and usually in that order. Avoidance behaviour or suppression is the most common reaction to an emerging conflict. If the use of power does not re-establish a balance between the participants, one negotiates. These conflict styles seem to be determined by two major factors: the perceived interdependence between parties and the perceived urgency of doing something about the situation. Nurses and physicians in particular seem to differ considerably in their perception of what is a conflict and when to do something about it. Such differences in perceptions and the extensive use of avoidance represent important challenges to managers and clinical leaders when it comes to advancing interprofessional co-operation.

  7. Military Training and Education: an Opportunity for V4 Co-Operation

    Directory of Open Access Journals (Sweden)

    Milan ŠUPLATA

    2015-03-01

    Full Text Available The Visegrad Group needs success stories if its defence co-operation is to develop. The recent differences between Poland and the rest of the region, as well as the closing window of opportunity to improve interoperability through the ISAF mission, make the hunger for concrete examples of co-operation even more urgent. Education and training projects are not only comparatively easily to implement in terms of time and money, but also represent a way of bringing the region’s civilian and military leaders closer together in terms of strategic thinking. Regional defence collaboration is also one of the ways to materialize NATO’s Smart Defence agenda. For the whole region, the way to keep Visegrad defence cooperation alive is not straightforward and certain, but it is likely to prove rewarding in the long term. It presents not only a chance to keep the whole region better prepared militarily, but also to build a more cohesive strategic awareness, thanks to intensive communication at all levels.

  8. Broadband down-conversion through the co-contribution of simultaneous energy transfer from Eu{sup 3+/2+} to Yb{sup 3+} and CTS absorption of Yb{sup 3+}

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Huiyun; Ye, Song, E-mail: yesong@tongji.edu.cn; Li, Song; Liu, Tianhua; Lin, Jian; Wang, Deping

    2015-11-05

    The europium (Eu) and ytterbium (Yb) co-doped SiO{sub 2}–Al{sub 2}O{sub 3}–MF{sub 2} (M = Ca, Sr) oxyfluoride glasses were prepared by the melting-quenching method, in which the partial reduction of Eu{sup 3+} ions during high temperature fabrication in air atmosphere was explained by optical basicity model. In this system, the near-infrared emission of Yb{sup 3+} at 974 nm can be observed upon the excitation of both Eu{sup 3+} and Eu{sup 2+}, as well as charge transfer state absorption of Yb{sup 3+}. The steady and time-resolved luminescence spectra measurements were carried out to further prove the energy transfer from Eu{sup 3+/2+} ions to Yb{sup 3+}. Based on the measured luminescence decay of Eu{sup 3+} and Eu{sup 2+}, the energy transfer efficiency and the quantum efficiency are much higher in the glass containing SrF{sub 2} due to the efficient energy transfer from both Eu{sup 3+} and Eu{sup 2+} to Yb{sup 3+}. - Highlights: • Partial reduction of Eu{sup 3+} to Eu{sup 2+} in silicate glass in air was obtained. • Simultaneous energy transfer from Eu{sup 3+/2+} to Yb{sup 3+} was proved. • Contribution of CTS absorption of Yb{sup 3+} to down-conversion was confirmed. • The distribution of Eu{sup 3+/2+} in glass matrix at different sites was discussed. • The influence of local non-uniform of glass on quantum efficiency was discussed.

  9. Low-noise quantum frequency down-conversion of indistinguishable photons (Conference Presentation)

    Science.gov (United States)

    Kambs, Benjamin; Kettler, Jan; Bock, Matthias; Becker, Jonas; Arend, Carsten; Jetter, Michael; Michler, Peter; Becher, Christoph

    2016-04-01

    Single-photon sources based on quantum dots have been shown to exhibit almost ideal properties such as high brightness and purity in terms of clear anti-bunching as well as high two-photon interference visibilities of the emitted photons, making them promising candidates for different quantum information applications such as quantum computing, quantum communication and quantum teleportation. However, as most single-photon sources also quantum dots typically emit light at wavelengths of electronic transitions within the visible or the near infrared range. In order to establish quantum networks with remote building blocks, low-loss single photons at telecom wavelengths are preferable, though. Despite recent progress on emitters of telecom-photons, the most efficient single-photon sources still work at shorter wavelengths. On that matter, quantum frequency down-conversion, being a nonlinear optical process, has been used in recent years to alter the wavelength of single photons to the telecom wavelength range while conserving their nonclassical properties. Characteristics such as lifetime, first-order coherence, anti-bunching and entanglement have been shown to be conserved or even improved due to background suppression during the conversion process, while the conservation of indistinguishability was yet to be shown. Here we present our experimental results on quantum frequency down-conversion of single photons emitted by an InAs/GaAs quantum dot at 903.6 nm following a pulsed excitation of a p-shell exciton at 884 nm. The emitted fluorescence photons are mixed with a strong pump-field at 2155 nm inside a periodically poled lithium niobate ridge waveguide and converted to 1557 nm. Common issues of a large background due to Raman-scattered pump-light photons spectrally overlapping with the converted single photons could largely be avoided, as the pump-wavelength was chosen to be fairly longer than the target wavelength. Additional narrowband spectral filtering at the

  10. Twenty Years of Co-operation between Spain and France: Friends, Partners or Allies?

    Directory of Open Access Journals (Sweden)

    Laia Mestres i Camps

    2006-11-01

    Full Text Available The progress made in the relations between France and Spain at the 18th Spanish- French Summit, held in Paris on 10 November 2005, demonstrate that relations between France and Spain are passing through a good moment, and at the same time it allows us to go deeper into the analysis of the co-operation between these two neighbours over the past twenty years. This article aims to examine the evolution of relations between Spain and France, which must administer a dense bilateral agenda as neighbours and anothermultilateral agenda as European partners. In other words, it will analyse the extent to which French-Spanish relations can become a balanced, stable alliance.

  11. Caffeinated coffee enhances co-operative behavior in the Mixed Motive Game in healthy volunteers.

    Science.gov (United States)

    Tse, Wai S; Chan, Chi Choi S; Shiu, Shun Yan K; Chung, Pik Yee A; Cheng, Shuk Han

    2009-02-01

    Caffeinated drinks are commonly consumed in social gatherings. However, their effects on social behavior remain unclear. The present study examined the effects of caffeinated coffee on antidepressant-related co-operative behavior. Seventy-seven low-caffeine users took part in a randomized, double-blind, cross-over study of single dose of caffeinated coffee (150 mg caffeine) and decaffeinated coffee (9 mg caffeine) with at least a 3-day washout period. In each session, participants were asked to imagine a fictitious person and play the Mixed Motive Game with that person 45 min after coffee consumption. Heart rate, blood pressure, and state moods were measured at baseline and at 45 min post-coffee consumption. After caffeinated coffee, participants exhibited significantly higher blood pressure. They also allocated significantly fewer scores to themselves and sent significantly more sadness message during the game. These results suggest that caffeinated coffee may help to improve social support and depressive symptoms.

  12. Out-of-hours palliative care provided by GP co-operatives: availability, content and effect of transferred information

    Directory of Open Access Journals (Sweden)

    Deliens Luc

    2009-01-01

    Full Text Available Abstract Background Out-of-hours GP care in England, Denmark and the Netherlands has been reorganised and is now provided by large scale GP co-operatives. Adequate transfer of information is necessary in order to assure continuity of care, which is of major importance in palliative care. We conducted a study to assess the availability, content and effect of information transferred to the GP co-operatives. Methods Cross-sectional exploratory study of all palliative care phone calls during a period of one year to a GP co-operative. Results The total number of phone calls about patients who needed palliative care was 0.75% of all calls to the GP co-operative. Information was transferred by GPs on 25.5% of palliative care patient calls, and on 12% of palliative care patient calls from residential care homes. For terminally ill patients the number of information transfers increased to 28.9%. When information was transferred, the content consisted mainly of clinical data. Information about the diagnosis and current problems was transferred in more than 90% of cases, information about the patient's wishes in 45% and information about the patient's psychosocial situation in 30.5% of cases. A home visit was made after 53% of the palliative care calls. When information was transferred, fewer patients were referred to a hospital. Conclusion GPs frequently fail to transfer information about their palliative care patients to the GP co-operatives. Locums working at the GP co-operative are thus required to provide palliative care in complex situations without receiving adequate information GPs should be encouraged and trained to make this information available to the GP co-operatives.

  13. Luminescence dating of Netherlands’ sediments

    OpenAIRE

    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 review: 1) the development of the methodology; 2) tests of the reliability of luminescence dating on Netherlands’ sediments; and 3) geological applications of the method in the Netherlands. Our review shows that optically stimulated luminescence dating of quartz grains using the single aliquot regenerative dose method yi...

  14. Sweden's Co-operation with Eastern Europe in Radiation Safety 2011

    Energy Technology Data Exchange (ETDEWEB)

    Dassen, Lars van; Andersson, Sarmite; Bejarano, Gabriela; Chirman, Inessa; Delalic, Zlatan; Ekblad, Christer; Karlberg, Olof; Klasen, Haakan; Olsson, Kjell; Sandberg, Viviana; Stenberg, Tor; Turner, Roland; Wickman, Barbro

    2012-11-01

    In 2011, the Swedish Radiation Safety Authority implemented co-operation projects in Russia, Ukraine, Georgia, Lithuania and Moldova, based on instructions from the Swedish Government and agreements with the European Union and the Swedish International Development Co-operation Agency, SIDA. The projects aim at achieving a net contribution to radiation safety (including nuclear safety, nuclear security, waste management, nonproliferation as well as radiation protection and emergency preparedness) for the benefit of the host countries and the international community as well as Sweden. This report gives an overview of all the projects implemented in 2011. The project managers from SSM are the cornerstones of our successful work, but all the efforts and dedication by staff members of the facilities and authorities in the mentioned countries are indispensable for the long-term positive outcomes. This report is meant to serve as a detailed account regarding SSM's efforts as part of the Swedish international activities, on which Sweden will report to the Nuclear Security Summit in Seoul. The parties to the G-8 Global Partnership have in June 2011 extended the Global Partnership for ten more years, till 2022. Other international frameworks, such as the UNSC Resolution 1540, remain a vibrant instrument by which UN Member States can exchange information on security concerns and request assistance from each other. The projects that SSM implements in Moldova and Georgia have a reference to the aims and purposes of the UNSC Resolution 1540. Much work has been done in the fields of nuclear security and safety, but there are still lots of issues that need to be taken care of. As such, SSM will continue to do its part for nuclear safety and security at the international level, along the lines and priorities set by our Government.

  15. Luminescent properties of aluminum hydride

    Energy Technology Data Exchange (ETDEWEB)

    Baraban, A.P.; Gabis, I.E.; Dmitriev, V.A. [Saint-Petersburg State University, Department of Physics, Saint-Petersburg 198504 (Russian Federation); Dobrotvorskii, M.A., E-mail: mstislavd@gmail.com [Saint-Petersburg State University, Department of Physics, Saint-Petersburg 198504 (Russian Federation); Kuznetsov, V.G. [Saint-Petersburg State University, Department of Physics, Saint-Petersburg 198504 (Russian Federation); Matveeva, O.P. [National Mineral Resources University, Saint Petersburg 199106 (Russian Federation); Titov, S.A. [Petersburg State University of Railway Transport, Saint-Petersburg 190031 (Russian Federation); Voyt, A.P.; Elets, D.I. [Saint-Petersburg State University, Department of Physics, Saint-Petersburg 198504 (Russian Federation)

    2015-10-15

    We studied cathodoluminescence and photoluminescence of α-AlH{sub 3}– a likely candidate for use as possible hydrogen carrier in hydrogen-fueled vehicles. Luminescence properties of original α-AlH{sub 3} and α-AlH{sub 3} irradiated with ultraviolet were compared. The latter procedure leads to activation of thermal decomposition of α-AlH{sub 3} and thus has a practical implementation. We showed that the original and UV-modified aluminum hydride contain luminescence centers ‐ structural defects of the same type, presumably hydrogen vacancies, characterized by a single set of characteristic bands of radiation. The observed luminescence is the result of radiative intracenter relaxation of the luminescence center (hydrogen vacancy) excited by electrons or photons, and its intensity is defined by the concentration of vacancies, and the area of their possible excitation. UV-activation of the dehydrogenation process of aluminum hydride leads to changes in the spatial distribution of the luminescence centers. For short times of exposure their concentration increases mainly in the surface regions of the crystals. At high exposures, this process extends to the bulk of the aluminum hydride and ends with a decrease in concentration of luminescence centers in the surface region. - Highlights: • Aluminum hydride contains hydrogen vacancies which serve as luminescence centers. • The luminescence is the result of radiative relaxation of excited centers. • Hydride UV-irradiation alters distribution and concentration of luminescence centers.

  16. Wound care in primary health care: district nurses' needs for co-operation and well-functioning organization.

    Science.gov (United States)

    Friman, Anne; Klang, Birgitta; Ebbeskog, Britt

    2010-01-01

    Most patients with leg- and foot ulcers are managed within non-institutional care. The aim of this study was to investigate the district nurses' wound management, including wound appearance, assignment of responsibility, guidelines for wound treatment and co-operation with other professional groups. The study has a descriptive quantitative approach. Data was collected using a wound registration form and a questionnaire. The selection of participants was made by random sampling. District nurses (n = 26) in five health-care centers situated in central Stockholm and two of its suburbs, participated in the study. The results show that the wound appearance is dominated by traumatic wounds. Approximately 40% of the wounds were not medically diagnosed. The area of responsibility of different professional groups was not defined and guidelines for wound treatment were mostly lacking. The decision about wound management was generally made by the district nurse. Co-operation with the general practitioner was lacking and when a consultation with dermatologist was required, the routines concerning referral were undefined. Co-operation with the assistant nurses consisted of redressing the wounds in home care. Interprofessional co-operation was regarded as important for wound healing. The paper provides insights into the district nurses' wound management and co-operation in wound care.

  17. GENERATION OF COMPLEMENTARY CODES AND DOUBLY CO-OPERATIVE TERNARY SEQUENCES AND THEIR COMPARITIVE STUDY IN AMBIGUITY DOMAIN

    Directory of Open Access Journals (Sweden)

    K. SRIHARI RAO,

    2011-03-01

    Full Text Available Pulse coding and linear frequency modulation in analog or discrete form are widely used in radar systems for pulse compression to achieve high range resolution. Such coded waveforms are detected by a threshold detector after matched filtering. Complementary codes, which use multiple binary sequences exhibit the most desirable characteristics, so that they achieve perfect side lobe cancellation.Here generation of complementary codes is presented whose sum of autocorrelation functions is double the length of the sequence for zero shift and zero for other shifts and pairs of doubly co-operative ternary sequences which are co-operative not only in the utocorrelation domain but also in the signal domain is presented. Theenergy efficiency of the sequences is found as unity or 100%. The hoice of the selection of the sequence in the case of complementary sequences is restricted to a few number of sequences where as in doubly co-operative sequences, the choice is broader. This is due to the property of the co-operative sequence is slightly relaxedfrom complementary codes as side lobe is relaxed to ±1 from zero in the case of complementary codes. The radar ambiguity function epresents the output of the matched filter used by the radar esigners which provides information about how different waveforms may be suitable for various radar applications. The behaviour of complementary sequences and doubly co-operative sequences is studied in ambiguity domain.

  18. New luminescent materials and filters for Luminescent Solar Concentrators

    NARCIS (Netherlands)

    De Boer, D.K.G.; Ronda, C.R.; Keur, W.C.; Meijerink, A.

    2012-01-01

    In a Luminescent Solar Concentrator (LSC), short-wavelength light isconverted by a luminescent material into long-wavelength light, which is guided towards a photovoltaic cell. In principle, an LSC allows for high concentration, but in practice this is prevented by lossmechanisms like limited sunlig

  19. Synthesis and Downconversion Emission Property of Yb2O3:Eu3+ Nanosheets and Nanotubes

    Directory of Open Access Journals (Sweden)

    Chao Qian

    2013-01-01

    Full Text Available Ytterbium oxide (Yb2O3 nanocrystals with different Eu3+ (1%, 2%, 5%, and 10% doped concentrations were synthesized by a facile hydrothermal method, subsequently by calcination at 700°C. The crystal phase, size, and morphology of prepared samples were characterized by X-ray diffraction (XRD and transmission electron microscopy (TEM. The results show that the as-prepared Yb2O3 nanocrystals with sheet- and tube-like shape have cubic phase structure. The Eu3+ doped Yb2O3 nanocrystals were revealed to have good down conversion (DC property and intensity of the DC luminescence can be modified by Eu3+ contents. In our experiment the 1% Eu3+ doped Yb2O3 nanocrystals showed the strongest DC luminescence among the obtained Yb2O3 nanocrystals.

  20. Effect of co-operative fuzzy c-means clustering on estimates of three parameters AVA inversion

    Indian Academy of Sciences (India)

    Rajesh R Nair; Suresh Ch Kandpal

    2010-04-01

    We determine the degree of variation of model fitness,to a true model based on amplitude variation with angle (AVA)methodology for a synthetic gas hydrate model,using co-operative fuzzy c-means clustering,constrained to a rock physics model.When a homogeneous starting model is used,with only traditional least squares optimization scheme for inversion,the variance of the parameters is found to be comparatively high.In this co-operative methodology,the output from the least squares inversion is fed as an input to the fuzzy scheme.Tests with co-operative inversion using fuzzy c-means with damped least squares technique and constraints derived from empirical relationship based on rock properties model show improved stability,model fitness and variance for all the three parameters in comparison with the standard inversion alone.

  1. 租税行政の国際的動向 : 協力的コンプライアンス(Co-operative Compliance)の意義と課題

    OpenAIRE

    宮崎, 綾望

    2015-01-01

    This article analyzes the Co-operative Compliance approach under Japanese tax law. OECD published "Co-operative Compliance : A FRAMEWORK - FROM ENHANCED RELATIONSHIP TO CO-OPERATIVE COMPLIANCE 2013." Within the Co-operative Compliance approach, large taxpayers and revenue bodies base their relationship on mutual understanding and trust. This report suggests that many countries have developed Co-operative Compliance. But, some commentators have questioned Co-operative Compliance and equality b...

  2. 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;

  3. Power dependence of upconversion luminescence

    NARCIS (Netherlands)

    Pollnau, Markus; Güdel, H.U.

    Spectroscopic data are of essential value for understanding the excitation mechanisms in luminescent and laser materials. Special attention has been devoted to the investigation of upconversion-induced luminescence, partly because of the availability of near-infrared pump sources for the excitation

  4. Danish environmental support fund for Eastern Europe. Co-operation development 1991-1996 and programme priority areas

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-08-01

    The publication gives an account of environmental co-operation between Denmark and 12 countries in Eastern Europe. The basis of co-operation is a country programme, describing present and future priority areas in the recipient countries, as an expression of common understanding between the Danish Environmental Protection Agency and the Ministry of Environment in the recipient countries. The publication also describe the environmental efforts made in 1991-1996 under the Danish Environmental Support Fund for Eastern Europe (DESF) administered by the DEPA. (au)

  5. Co-operation in Collection Development : Summary of the Meeting of the Division of Collection Development, Prague, July 1999

    Directory of Open Access Journals (Sweden)

    Ann Wade

    1999-05-01

    Full Text Available Bernard Naylor gave a summary of some important milestones leading up to the present situation in library co-operation in the UK. From 1979 to 1986 three reports from the UK Library and Information Services Council on the future development of libraries had been published. The reports had argued for a cross sectoral approach to any attempts at co-operation, for a regional focus, and for local information plans. The reports also emphasized that all planning involved participation both from the top/down and from the bottom/up. All reports had made clear that only limited funds would be available for future planning.

  6. Co-operation at work: a process-oriented perspective on joint activity in inter-organizational relations.

    Science.gov (United States)

    Wehner, T; Clases, C; Bachmann, R

    2000-07-01

    In this paper the authors present a conceptual framework for analysing co-operation between organizations as a situated process, highlighting co-operation, co-ordination and co-construction as different modes of joint activity. Within this framework, the analysis of unexpected events becomes a crucial issue. The analytic power of reconstructing the (psycho-) logics of unexpected events in inter-organizational relations will be demonstrated in the presentation of selected outcomes of a research project on the dynamics of producer-supplier relationships in the German automobile industry. Also in this empirical part, the significance of trust and confidence in inter-organizational relations will be reflected.

  7. 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.

  8. High-performance alternating current field-induced chromatic-stable white polymer electroluminescent devices employing a down-conversion layer

    Energy Technology Data Exchange (ETDEWEB)

    Xia, Yingdong; Chen, Yonghua; Smith, Gregory M. [Center for Nanotechnology and Molecular Materials, Department of Physics, Wake Forest University, Winston-Salem, NC 27105 (United States); Sun, Hengda; Yang, Dezhi [State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Nie, Wanyi; Li, Yuan; Huang, Wenxiao [Center for Nanotechnology and Molecular Materials, Department of Physics, Wake Forest University, Winston-Salem, NC 27105 (United States); Ma, Dongge [State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Carroll, David L., E-mail: carroldl@wfu.edu [Center for Nanotechnology and Molecular Materials, Department of Physics, Wake Forest University, Winston-Salem, NC 27105 (United States)

    2015-05-15

    In this work, a high-performance alternating current (AC) filed-induced chromatic-stable white polymer electroluminescence (WFIPEL) device was fabricated by combining a fluorophor Poly(9,9-dioctylfluorene) (PFO)-based blue device with a yellow down-conversion layer (YAG:Ce). A maximum luminance of this down-conversion FIPEL device achieves 3230 cd m{sup −2}, which is 1.41 times higher than the device without the down-conversion layer. A maximum current efficiency and power efficiency of the down-conversion WFIPEL device reach 19.7 cd A{sup −1} at 3050 cd m{sup −2} and 5.37 lm W{sup −1} at 2310 cd m{sup −2} respectively. To the best of our knowledge, the power efficiency is one of the highest reports for the WFIPEL up to now. Moreover, Commison Internationale de L’Eclairage (CIE) coordinates of (0.28, 0.30) is obtained by adjusting the thickness of the down-conversion layer to 30 μm and it is kept stable over the entire AC-driven voltage range. We believe that this AC-driven, down-conversion, WFIPEL device may offer an easy way towards future flat and flexible lighting sources. - Highlights: • A high-performance AC filed-induced chromatic-stable white polymer electroluminescence (WFIPEL) device was fabricated. • A maximum luminance, current efficiency, and power efficiency achieves 3230 cd m{sup −2}, 19.7 cd A{sup −1}, and 5.37 lm W{sup −1}, respectively. • The power efficiency is one of the highest reports for the WFIPEL up to now. • The EL spectrum kept very stable over the entire AC-driven voltage range.

  9. Digital coherent detection of multi-gigabit 40 GHz carrier frequency radio-over-fiber signals using photonic downconversion

    DEFF Research Database (Denmark)

    Caballero Jambrina, Antonio; Zibar, Darko; Tafur Monroy, Idelfonso

    Detection of high speed radio signals is a challenge for next generation radio-over-fiber links, requiring high bandwidth and linearity in the receiver. By using photonic downconversion in a coherent receiver, it is possible to detect signals exceeding the electrical bandwidth of the receiver......, by performing the mixing of the radio signal with a free-running local oscillator in the optical domain. In this paper we present the experimental emonstration of high bitrate 16-QAM signal detection, up to 4 Gb/s, at 40 GHz carrier frequency, using low bandwidth electronics....

  10. Down-conversion photoluminescence sensitizing plasmonic silver nanoparticles on ZnO nanorods to generate hydrogen by water splitting photochemistry

    Energy Technology Data Exchange (ETDEWEB)

    Kung, Po-Yen; Huang, Li-Wen; Shen, Tin-Wei; Wang, Wen-Lin; Su, Yen-Hsun [Department of Materials Science and Engineering, National Cheng Kung University, Tainan, Taiwan (China); Lin, Melody I. [Department of Physics, University of California, Berkeley, California, 94720 (United States)

    2015-01-12

    Silver nanoparticles fabricated onto the surface of the ZnO nanorods form the photoanode and generate photoelectric current due to surface plasmon resonance, which serves as anode electrodes in photoelectrochemical hydrogen production. In order to increase the absorption spectrum of photoanode, organic pigments were utilized as photo-sensitizers to generate down-conversion photoluminescence to excite surface plasmon resonances of silver nanoparticles. The way of using light to carry the energy in electronic scattering regime runs the system for the enhancement of solar water splitting efficiency. It was significantly tuned in environmentally sustainable applications for power generation and development of alternative energy.

  11. W-band OFDM Radio-over-Fiber system with power detector for vector signal down-conversion.

    Science.gov (United States)

    Lin, Chun-Ting; Wu, Meng-Fan; Ho, Chun-Hung; Li, Che-Hao; Lin, Chi-Hsiang; Huang, Hou-Tzu

    2015-06-01

    This Letter proposes a W-band OFDM RoF system at 103.5 GHz employing power detector to support vector signal down-conversion. Additional RF tone is generated and transmitted from central office to replace the local oscillator at a wireless receiver. With a proper frequency gap and power ratio between the RF tone and the OFDM-modulated signal, the impact from signal-to-signal beating interference can be minimized. The data rate can achieve a 40 Gbps 16 QAM OFDM signal over 25 km fiber and 2 m wireless transmission.

  12. Stored Luminescence Computed Tomography

    CERN Document Server

    Cong, Wenxiang; Wang, Ge

    2013-01-01

    The phosphor nanoparticles made of doped semiconductors, pre-excited by well-collimated X-ray radiation, were recently reported for their light emission upon NIR light stimulation. The characteristics of X-ray energy storage and NIR stimulated emission is highly desirable to design targeting probes and improve molecular and cellular imaging. Here we propose stored luminescence computed tomography (SLCT), perform realistic numerical simulation, and demonstrate a much-improved spatial resolution in a preclinical research context. The future opportunities are also discussed along this direction.

  13. Luminescent macrocyclic lanthanide complexes

    Science.gov (United States)

    Raymond, Kenneth N [Berkeley, CA; Corneillie, Todd M [Campbell, CA; Xu, Jide [Berkeley, CA

    2012-05-08

    The present invention provides a novel class of macrocyclic compounds as well as complexes formed between a metal (e.g., lanthanide) ion and the compounds of the invention. Preferred complexes exhibit high stability as well as high quantum yields of lanthanide ion luminescence in aqueous media without the need for secondary activating agents. Preferred compounds incorporate hydroxy-isophthalamide moieties within their macrocyclic structure and are characterized by surprisingly low, non-specific binding to a variety of polypeptides such as antibodies and proteins as well as high kinetic stability. These characteristics distinguish them from known, open-structured ligands.

  14. SECURITY CO-OPERATION IN THE SOUTHERN AFRICAN DEVELOPMENT COMMUNITY: INSIGHTS FROM THE NEW INSTITUTIONALISM

    Directory of Open Access Journals (Sweden)

    Anthoni Van Nieuwkerk

    2011-08-01

    Full Text Available This article focuses on the institutional dimensions of security cooperationas it manifests in the Southern African Development Community(SADC. As the quotations above suggest, security co-operation, as part of a biggerproject of regional integration, is not obvious. Indeed, should southern Africansbelieve their politicians when the latter claim that SADC is ‘forging ahead’ on theroad to formal integration? Slabbert is not convinced. Not only academics, but civilsociety increasingly question its raison d’ etre. For many, it is unclear whether orhow SADC provides human security to the people of the region. Instead, SADCmembers’ positions on the key regional challenges (trade, growth and development,security and stability are driven by national interest rather than regional interest – asrealists argue, national interests (a must-have are hard and measurable; regional cooperation(often a nice-to-have is hard to measure. Or should we accept a regionalconsciousness shaped by a shared historical experience – a problematic assumption?

  15. Concentrating on Solar Power in a Trans-Mediterranean Renewable Energy Co-Operation

    Science.gov (United States)

    Trieb, F.; Kronshage, S.; Knies, G.

    2004-12-01

    Combining the large demand of clean electricity in Europe (EU) with the large potential of solar electricity generation from concentrating solar power stations (CSP) in the Middle East and North Africa (MENA) can provide both climate protection and development for both regions and lead to environmental, economical and social sustainability. The presentation will address the concept of solar cogeneration of electricity and desalted water and the scope of generating clean power for MENA and Europe while providing large quantities of freshwater for the MENA countries. Costs and benefits of the concept will be quantified, and the first steps to realisation within the Trans-Mediterranean Renewable Energy Co-Operation TREC are presented. After running through the technology learning curve within about 10-15 years, concentrated solar electricity will be generated at a cost of roughly 4 ct/kWh. Importing solar power from North Africa to Europe, will add 1 ct/kWh, thus being competitive with new fuel fired plants. The total initial support of about 1 billion € needed to trigger CSP market introduction and to achieve forever low electricity costs in the EU and MENA, equals 25 % of the German annual coal subsidies, 1 month of EU agronomic-subsidies or 1 day of US military expenses and could be provided in form of public investment, soft loans or feed-in guaranties like the German Renewable Energy Act.

  16. Co-operative Scheduled Energy Aware Load-Balancing technique for an Efficient Computational Cloud

    Directory of Open Access Journals (Sweden)

    T R V Anandharajan

    2011-03-01

    Full Text Available Cloud Computing in the recent years has been taking its evolution from the scientific to the non scientific and commercial applications. Power consumption and Load balancing are very important and complex problem in computational Cloud. A computational Cloud differs from traditional high-performance computing systems in the heterogeneity of the computing nodes, as well as the communication links that connect the different nodes together. Load Balancing is a very important component in the commodity services based cloud computing. There is a need to develop algorithms that can capture this complexity yet can be easily implemented and used to solve a wide range of load-balancing scenarios in a Data and Computing intensive applications. In this paper, we propose to find the best EFFICIENT cloud resource by Co-operative Power aware Scheduled Load Balancing solution to the Cloud load-balancing problem. The algorithm developed combines the inherent efficiency of the centralized approach, energy efficient and the fault-tolerant nature of the distributed environment like Cloud.

  17. Co-operative Wireless Intrusion Detection System Using MIBs From SNMP

    Directory of Open Access Journals (Sweden)

    Ashvini Vyavhare

    2012-03-01

    Full Text Available In emerging technology of Internet, security issues are becoming more challenging. In case of wired LAN it is somewhat in control, but in case of wireless networks due to exponential growth in attacks, it has made difficult to detect such security loopholes. Wireless network security is being addressed using firewalls, encryption techniques and wired IDS (Intrusion Detection System methods. But the approaches which were used in wired network were not successful in producing effective results for wireless networks. It is so because of features of wireless network such as open medium, dynamic changing topology, cooperative algorithms, lack of centralized monitoring and management point, and lack of a clear line of defense etc. So, there is need for new approach which will efficiently detect intrusion in wireless network. Efficiency can be achieved by implementing distributive, co-operative based, multi-agent IDS. The proposed system supports all these three features. It includes mobile agents for intrusion detection which uses SNMP (Simple network Management Protocol and MIB (Management Information Base variables for mobile wireless networks

  18. Effect of Oral Midazolam Premedication on Children's Co-operation Before General Anesthesia in Pediatric Dentistry.

    Science.gov (United States)

    Kaviani, Nasser; Shahtusi, Mina; Haj Norousali Tehrani, Maryam; Nazari, Sara

    2014-09-01

    Premedication is expedient in reducing the psychological trauma from recalling the unpleasant pre-anesthetic phases, hence, inducing a trouble-free anesthesia. This study aimed to determine the effectiveness of oral midazolam in co-operation of the subjects before general anesthesia and in recalling the pre-anesthetic phases, performed on children candidate for dental treatment under general anesthesia. In this prospective clinical trial study, 62 healthy non-cooperative children, candidate for dental treatment under general anesthesia, were randomly divided into study and control groups. The children received 20ml orange juice, 20 minutes before starting the anesthesia. The juice of the test group contained 0.5mg/kg of midazolam and that of the control group included no medication. The induction and the maintenance process of anesthesia were similar in both groups. The manner of subjects when separated from parents, their cooperation during intravenous catheterization, and recalling the pre-anesthetic events were recorded. Data were analyzed by adopting chi-square and Mann-Whitney tests. Most of the children in the test group had a comfortable separation from parents, restful IV catheterization and 90% of the subjects did not recall the pre-anesthetic events. Under the circumstances of this study, it could be concluded that 0.5mg/kg oral midazolam premedication is effective for comfortable separation of children from parents and restful IV catheterization and also forgetting the pre-anesthetic events.

  19. UEFA and the European Union: From Confrontation to Co-operation?

    Directory of Open Access Journals (Sweden)

    Borja García

    2007-12-01

    Full Text Available This article investigates the relationship between UEFA, as European football’s governing body, and the EU. It assesses the evolution of UEFA as a football governing body since the Bosman ruling (1995 until current initiatives such as the rules on locally-trained players (2005-2006. The paper traces the evolution of UEFA’s reactions to the increasing involvement of EU institutions in football matters, with special focus on the regulation of the players’ market. It is argued that UEFA’s attitude towards the EU has changed in the last ten years. Whilst the EU was seen as a threat for UEFA in 1995, it is now considered a ‘long term strategic partner’. Two main reasons can be identified for UEFA’s evolution. First and foremost, UEFA has been forced to accept the primacy of European law and its application to the activities of football organisations. UEFA has had no option but to adapt to the impact of European law and policies on its activities. This has lead to a relationship of ‘supervised’ autonomy between UEFA and the EU institutions. Second, UEFA’s strategic vision to preserve its own position within the governance structures of football. UEFA has tried to enhance its legitimacy within football’s governing structures by engaging in policy co-operation with EU authorities. This paper draws almost entirely on empirical research conducted through elite interviews and the review of official documents.

  20. A Distributed and Co-Operative Approach To Botnet Detection Using Gossip Protocol

    Directory of Open Access Journals (Sweden)

    Manoj Rameshchandra Thakur

    2012-07-01

    Full Text Available Bots, in recent times, have posed a major threat to enterprise networks. With the distributed nature of the way in which botnets operate, the problems faced by enterprises have become acute. A bot is a programme that operates as an agent for a user and runs automated tasks over the internet, at a much higher rate than would be possible for a human alone. A collection of bots in a network, used for malicious purposes, is referred to as a botnet. In this paper we suggested a distributed, co-operative approach towards detecting botnets is a given network which is inspired by the gossip protocol. Each node in a given network runs a standalone agent that computes a suspicion value for that node after regular intervals. Each node in the network exchanges its suspicion values with every other node in the network at regular intervals. The use of gossip protocol ensures that if a node in the network is compromised, all other nodes in the network are informed about it as soon as possible. Each node also ensures that at any instance, by means of the gossip protocol, it maintains the latest suspicion values of all the other nodes in the network.

  1. Japanese lunar robotics exploration by co-operation with lander and rover

    Indian Academy of Sciences (India)

    Takashi Kubota; Yasuharu Kunii; Yoji Kuroda

    2005-12-01

    Unmanned mobile robots for surface exploration of the Moon or planets have been extensively studied and developed.A lunar rover is expected to travel safely in a wide area and explore in detail. Japanese lunar robotics exploration is under study to conduct an unmanned geological survey in the vicinity of central peaks of impact craters for investigation of the sub-surface materials.This will give us the key information to study the lunar inner structure and understand the Moon ’s origin and evolution as well as to investigate the evolution of magma ocean and later igneous processes.To carry out the geological exploration in the central peak,lander and rover co-operative exploration is proposed.The working group has been conducting feasibility study of advance technologies.This paper addresses an overview of lunar exploration with lander and rover and also enumerates future technologies to be established. The rover R&D group has developed an innovative science micro rover with a new mobility system and a lightweight manipulator.The design and implementation of a science rover for the near future lunar missions requiring long traverses and scientific observations are described and some experimental results are presented.

  2. Prevention of Co-operative Black Hole attack in Manet on DSR protocol using Cryptographic Algorithm

    Directory of Open Access Journals (Sweden)

    G.Vennila

    2014-10-01

    Full Text Available The Mobile ad-hoc network (MANET is a collection of wireless mobile node in which each node can communicate with other node without use of predefined infrastructure. Currently, a lot of efficient protocols have been proposed for MANET. All of these efficient Routing protocols are depends only conviction and supportive environment. Conversely, the networks are more vulnerable to various kinds of routing attacks with the presence of malicious nodes. Black hole attack is one of network layer attack. In this attack, A malicious node make use of routing protocol to advertise itself that has a shortest path to reach destination, drops at the cost of original routing packets. In our work, the proposed algorithm is used to secure the DSR protocol. This will help to improve the performance of Mobile Ad hoc network due to the attack. There are several prevention mechanisms to eliminate the Black Hole attack in MANET. The aim of the paper is to provide better prevention of Co-operative Black hole attack in MANET and how it affects the performance metrics in terms of throughput and delay of the network by comparing the network performance with and without black hole nodes.

  3. Eu2+ activated persistent luminescent materials

    NARCIS (Netherlands)

    Dutczak, D.A.

    2013-01-01

    This thesis deals with luminescence and persistent luminescence of Eu2+ activated materials and aims at unraveling the mechanism behind the persistent luminescence, in particular the role of Dy3+ in the physical process leading to persistent luminescence. The second aim of this thesis is the

  4. Optoelectronic down-conversion by four-wave mixing in a highly nonlinear fiber for millimeter-wave and THz phase-locking

    CERN Document Server

    Rolland, Antoine; Brunel, Marc; Alouini, Mehdi

    2014-01-01

    Optoelectronic down-conversion of a THz optical beatnote to a RF intermediate frequency is performed with a standard Mach-Zehnder modulator followed by a zero dispersion-slope fiber. The two interleaved optical spectra obtained by four-wave mixing are shown to contain more than 75 harmonics enabling to conveniently recover the phase noise of a beatnote at 770 GHz at around 500 MHz. This four-wave mixing down-conversion technique is implemented in a two-frequency solid-state laser in order to directly phase-lock its 168 GHz beatnote to a 10 MHz local oscillator.

  5. Pr3+,Yb3+共掺YPO4下转换材料的制备及其转光效率%Downconversion Materials Preparation and The Research of Conversion Efficiency in Pr3+ , Yb3+ Co-doped YPO4

    Institute of Scientific and Technical Information of China (English)

    李开宇; 王如志; 曲铭浩; 张影; 严辉

    2012-01-01

    Pr3+ , Yb3+ co-doped YPO4 downconversion phosphor powders were prepared by solid state reaction. When excitation at 450 nm, the effects of different Yb3+ mole fractions (0% , 1% , 2% ,4% ,20% ,30% ) on the conversion efficiency are studied. Results shows that because of the difference of energy transfer efficiency between Pr3+ and Yb3+ , the samples with various Yb3+ doping concentrations have different fluorescence intensity. It is also found that the energy transfer process of the downconversion luminescence in samples is Pr3+ ;3P0-Yb3+:2F5/2 +2F5/2. From photoluminescence spectra measurement, the optimal doping mole fraction of Yb3* is 2%. The results indicate that Pr3+ , Yb3+ co-doped YPO4 downconversion phosphor is a kind of potential material which may be used to improve the solar cell efficency.%采用固相反应法制备了Pr3+,Yb3共掺杂的YPO4下转换发光粉体,并在450 nm光激发条件下,研究了Yb3+不同摩尔分数(0%,1%,2%,4%,20%,30%)对转光效率的影响.结果表明:不同Yb3+浓度的样品,其荧光峰强度不同,这可能是由于Pr3+ -Yb3之间Yb3+浓度不同存在能量传递效率差异的原因.研究也发现了样品的下转换发光,其能量传递过程为:Pr3+∶3P0→Yb3+∶2F5/2+2F5/2.荧光光谱测试结果表明,Yb3+的最佳掺杂摩尔分数为2%.Pr3+,Yb3+共掺杂的YPO4材料在提高太阳能电池光电转换效率方面具有潜在的应用.

  6. Student Perceptions of Social Learning Space: Designing and Implementing a Co-Operative Assessment Task in Pharmacology

    Science.gov (United States)

    Moni, Roger W.; Depaz, Iris; Lluka, Lesley J.

    2008-01-01

    We report findings from a case study of co-operative, group-based assessment in Pharmacology for second-year undergraduates at The University of Queensland, Australia. Students enrolled in the 2005 Bachelor of Science and 2006 Bachelor of Pharmacy degree programs, were early users of the university's new Collaborative Teaching and Learning Centre…

  7. Manual of electric power conservation. Residential co-operatives buildings; Manual de conservacao de energia eletrica. Condominios residenciais

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1993-01-01

    Procedures to electric power consumption optimization, and energy conservation on residential co-operative buildings are presented. Lighting consumption profiles, lamps and its lighting characteristic table, internal program to energy conservation, some information about energy consumption optimization, water consumption, energy costs, performance evaluation and safety patterns on electric plants are discussed. 25 figs., 5 tabs.

  8. A Co-operative Inquiry Into Generating, Describing, and Transforming Knowledge About De-escalation Practices in Mental Health Settings

    DEFF Research Database (Denmark)

    Berring, Lene Lauge; Hummelvoll, Jan Kåre; Pedersen, Liselotte

    2016-01-01

    De-escalation is concerned with managing violent behaviour without resorting to coercive measures. Co-operative Inquiry provided the conceptual basis for generating knowledge regarding de-escalation practices in acute mental health care settings. The research included service users and staff...

  9. Is the Ownership Structure Model a Decisive Determinant of Co-Operatives' Financial Success? A Financial Assessment

    NARCIS (Netherlands)

    Kalogeras, N.; Pennings, J.M.E.; Kuikman, J.; Doumpos, M.

    2011-01-01

    Abstract. In this paper, the financial/ownership structures of agribusiness co-operatives (co-ops) are analyzed in order to examine whether new co-op models perform better than the more traditional ones. The assessment procedure introduces a new financial decision-aid approach, which is based on dat

  10. The Effect of Interviewer Experience, Attitudes, Personality and Skills on Respondent Co-operation with Face-to-Face Surveys

    Directory of Open Access Journals (Sweden)

    Annette Jäckle

    2012-12-01

    Full Text Available This paper examines the role of interviewers' experience, attitudes, personality traits and inter-personal skills in determining survey co-operation, conditional on contact. We take the perspective that these characteristics influence interviewers' behaviour and hence influence the doorstep interaction between interviewer and sample member. Previous studies of the association between doorstep behaviour and co-operation have not directly addressed the role of personality traits and inter-personal skills and most have been based on small samples of interviewers. We use a large sample of 842 face-to-face interviewers working for a major survey institute and analyse co-operation outcomes for over 100,000 cases contacted by those interviewers over a 13-month period. We find evidence of effects of experience, attitudes, personality traits and inter-personal skills on co-operation rates. Several of the effects of attitudes and inter-personal skills are explained by differences in experience, though some independent effects remain. The role of attitudes, personality and skills seems to be greatest for the least experienced interviewers.

  11. Student Perceptions of Social Learning Space: Designing and Implementing a Co-Operative Assessment Task in Pharmacology

    Science.gov (United States)

    Moni, Roger W.; Depaz, Iris; Lluka, Lesley J.

    2008-01-01

    We report findings from a case study of co-operative, group-based assessment in Pharmacology for second-year undergraduates at The University of Queensland, Australia. Students enrolled in the 2005 Bachelor of Science and 2006 Bachelor of Pharmacy degree programs, were early users of the university's new Collaborative Teaching and Learning Centre…

  12. Towards co-operative governance in the development and implementation of cross-sectoral policy: water policy as an example

    CSIR Research Space (South Africa)

    MacKay, HM

    2004-01-01

    Full Text Available to be established on the ground, and not just considered as some form of laudable principle. One of the most important steps in moving towards operational co-operative governance is the identification and agreement, by all the relevant and affected sectors...

  13. Managing technical-institutional design processes: some strategic lessons from environmental co-operatives in the Netherlands

    NARCIS (Netherlands)

    Roep, D.; Ploeg, van der J.D.; Wiskerke, J.S.C.

    2003-01-01

    In this paper the case of the environmental co-operatives VEL and VANLA is reviewed in terms of coevolving technical and institutional change and the strategic lessons to be learned for a pro-active management of such complex technical-institutional design processes. Facing the many-sided crisis in

  14. Eu2+ activated persistent luminescent materials

    OpenAIRE

    Dutczak, D.A.

    2013-01-01

    This thesis deals with luminescence and persistent luminescence of Eu2+ activated materials and aims at unraveling the mechanism behind the persistent luminescence, in particular the role of Dy3+ in the physical process leading to persistent luminescence. The second aim of this thesis is the preparation and characterization of persistent luminescence phosphors emitting at different colors, especially yellow and red, where there is a need for better afterglow materials. A range of aluminates, ...

  15. The Use of Relationship Marketing in Developing Network and Co-operative links within Tourism Product Marketing Groups (PMG’s

    OpenAIRE

    Gorman, Catherine

    2006-01-01

    Co-operative marketing groups are common in tourism, particularly in the case of destination marketing. Destination tourism marketing groups offer a diverse range of tourism products and experiences which complement each other and are delineated by a specific geographical parameter. Tourism product marketing groups offer similar tourism products or services and through a co-operative approach focus on an identified target markets. Co-operative marketing can make greater impact in terms of...

  16. Luminescence decay of porous silicon

    Science.gov (United States)

    Chen, X.; Uttamchandani, D.; Sander, D.; O'Donnell, K. P.

    1993-04-01

    The luminescence decay pattern of porous silicon samples prepared by electrochemical etching is characterised experimentally by a non-exponential profile, a strong dependence on temperature and an absence of spectral diffusion. We describe this luminescence as carrier-dopping-assisted recombination. Following the correlation function approach to non-dispersive transport developed by Scher and co-workers [Physics Today 41 (1991) 26], we suggest a simple derivation of analytical functions which accurately describes the anomalous luminescence decay of porous silicon, and show that this model includes exponential and Kohlrausch [Pogg. Ann. Phys. 119 (1863) 352] (stretched-exponential) relaxations as special cases.

  17. Temperature lags of luminescence measurements in a commercial luminescence reader

    Energy Technology Data Exchange (ETDEWEB)

    Kitis, George [Aristotle University of Thessaloniki, Nuclear Physics Laboratory, 54124 Thessaloniki (Greece); Kiyak, Nafiye G. [ISIK University, Faculty of Science and Arts, Physics Department, Sile, 34980 Istanbul (Turkey); Polymeris, George S., E-mail: gspolymeris@ankara.edu.tr [Ankara University, Institute of Nuclear Sciences, Beşevler, 06100 Ankara (Turkey)

    2015-09-15

    The temperature recorded in thermoluminescence and optically stimulated luminescence equipments is not the temperature of the sample but that of the heating element on which the thermocouple is attached. Depending upon the rate of heating, a temperature difference appears between the samples and the heating element, termed as temperature lag, which could have serious effects on the curve shapes and trapping parameters. In the present work the temperature lag effect is studied in a newly developed luminescence equipment measuring both thermoluminescence and optically stimulated luminescence. It is found that the temperature lag could be large for heating rates above 2 K/s and it is strongly dependent upon the sample holder. A simple approximation method is proposed in order to both predict as well as correct for temperature lag effects in luminescence measurements.

  18. Luminescent and Non-Luminescent Solar Concentrators: Challenges andd Progress

    NARCIS (Netherlands)

    De Boer, D.K.G.

    2012-01-01

    Luminescent concentrators would allow for high concentration if losses by reabsorption and escape could be minimized. We present new phosphors and filters that facilitate this. Another type of lightguide-based concentrators, diffraction-based, is discussed as well.

  19. Luminescent and Non-Luminescent Solar Concentrators: Challenges andd Progress

    NARCIS (Netherlands)

    De Boer, D.K.G.

    2012-01-01

    Luminescent concentrators would allow for high concentration if losses by reabsorption and escape could be minimized. We present new phosphors and filters that facilitate this. Another type of lightguide-based concentrators, diffraction-based, is discussed as well.

  20. Luminescent hyperbolic metasurfaces

    Science.gov (United States)

    Smalley, J. S. T.; Vallini, F.; Montoya, S. A.; Ferrari, L.; Shahin, S.; Riley, C. T.; Kanté, B.; Fullerton, E. E.; Liu, Z.; Fainman, Y.

    2017-01-01

    When engineered on scales much smaller than the operating wavelength, metal-semiconductor nanostructures exhibit properties unobtainable in nature. Namely, a uniaxial optical metamaterial described by a hyperbolic dispersion relation can simultaneously behave as a reflective metal and an absorptive or emissive semiconductor for electromagnetic waves with orthogonal linear polarization states. Using an unconventional multilayer architecture, we demonstrate luminescent hyperbolic metasurfaces, wherein distributed semiconducting quantum wells display extreme absorption and emission polarization anisotropy. Through normally incident micro-photoluminescence measurements, we observe absorption anisotropies greater than a factor of 10 and degree-of-linear polarization of emission >0.9. We observe the modification of emission spectra and, by incorporating wavelength-scale gratings, show a controlled reduction of polarization anisotropy. We verify hyperbolic dispersion with numerical simulations that model the metasurface as a composite nanoscale structure and according to the effective medium approximation. Finally, we experimentally demonstrate >350% emission intensity enhancement relative to the bare semiconducting quantum wells.

  1. Core-shell-like Y2O3:[(Tb3+-Yb3+), Li+]/CdZnS heterostructure synthesized by super-close-space sublimation for broadband down-conversion.

    Science.gov (United States)

    Wu, Xiaojie; Zhang, Zhenzhong; Meng, Fanzhi; Yu, Yingning; Han, Lin; Liu, Xiaojuan; Meng, Jian

    2014-05-07

    Combination with semiconductors is a promising approach to the realization of broadband excitation of light conversion materials based on rare earth compounds, to boost the energy efficiency of silicon solar cells. Cd(1-x)Zn(x)S is a wide bandgap semiconductor with large exciton binding energy. By changing its composition, the bandgap of Cd(1-x)Zn(x)S can be tuned to match the absorption of trivalent lanthanide (Ln) ions, which makes it a competent energy donor for the Ln(3+)-Yb(3+) couple. In this work, we designed a clean route to a broadband down-converter based on a core-shell-like Y2O3:[(Tb(3+)-Yb(3+)), Li(+)]/Cd0.81Zn0.19S (CdZnS) heterostructure. By hot-pressing and subsequent annealing of a Y2O3:[(Tb(3+)-Yb(3+)), Li(+)]/CdZnS mixture, highly pure CdZnS was sublimated and deposited on the Y2O3:[(Tb(3+)-Yb(3+)), Li(+)] grains while maintaining the original composition of the precursor. The CdZnS shell acted as a light absorber and energy donor for the Tb(3+)-Yb(3+) quantum cutting couple. Because the use of solvents was avoided during the formation of the heterostructures, few impurities were incorporated into the samples, and the non-radiative transition was therefore markedly suppressed. The Y2O3:[(Tb(3+)-Yb(3+)), Li(+)]/CdZnS heterostructures possess strong near-infrared (NIR) luminescence from Yb(3+). Broadband down-conversion to the Yb(3+) NIR emission was obtained in a wide range of 250-650 nm.

  2. Lanthanide-based luminescence biolabelling.

    Science.gov (United States)

    Sy, Mohamadou; Nonat, Aline; Hildebrandt, Niko; Charbonnière, Loïc J

    2016-04-14

    Luminescent lanthanide complexes display unrivalled spectroscopic properties, which place them in a special category in the luminescent toolbox. Their long-lived line-like emission spectra are the cornerstones of numerous analytical applications ranging from ultrasensitive homogeneous fluoroimmunoassays to the study of molecular interactions in living cells with multiplexed microscopy. However, achieving such minor miracles is a result of years of synthetic efforts and spectroscopic studies to understand and gather all the necessary requirements for the labels to be efficient. This feature article intends to survey these criteria and to discuss some of the most important examples reported in the literature, before explaining in detail some of the applications of luminescent lanthanide labels to bioanalysis and luminescence microscopy. Finally, the emphasis will be put on some recent applications that hold great potential for future biosensing.

  3. Detrimental nonlocality in luminescence measurements

    Science.gov (United States)

    Pluska, Mariusz; Czerwinski, Andrzej

    2017-08-01

    Luminescence studies are used to investigate the local properties of various light-emitting materials. A critical issue of these studies is presented that the signals often lack all advantages of luminescence-studies of high locality, and may originate from an extended spatial region of even a few millimeters in size or the whole sample, i.e., places other than intended for investigation. This is a key problem for research and development in photonics. Due to this nonlocality, information indicating defects, irregularities, nonuniformities and inhomogeneities is lost. The issue refers to typical structures with a strong built-in electric field. Such fields exist intentionally in most photonic structures and occur unintentionally in many other materials investigated by applied physics. We reveal [using test samples prepared with focused ion beam (FIB) on an AlGaAs/GaAs laser heterostructure with an InGaAs quantum well (QW)] that nonlocality increases at low temperatures. This is contrary to the widely expected outcome, as low-temperature luminescence measurements are usually assumed to be free from disturbances. We explain many effects observed due to nonlocality in luminescence studies and prove that separation of the investigated area by focused ion beam milling is a practical solution enabling truly local luminescence measurements. All conclusions drawn using the example of cathodoluminescence are useful for other luminescence techniques.

  4. Design and implementation of co-operative control strategy for hybrid AC/DC microgrids

    Science.gov (United States)

    Mahmud, Rasel

    This thesis is mainly divided in two major sections: 1) Modeling and control of AC microgrid, DC microgrid, Hybrid AC/DC microgrid using distributed co-operative control, and 2) Development of a four bus laboratory prototype of an AC microgrid system. At first, a distributed cooperative control (DCC) for a DC microgrid considering the state-of-charge (SoC) of the batteries in a typical plug-in-electric-vehicle (PEV) is developed. In DC microgrids, this methodology is developed to assist the load sharing amongst the distributed generation units (DGs), according to their ratings with improved voltage regulation. Subsequently, a DCC based control algorithm for AC microgrid is also investigated to improve the performance of AC microgrid in terms of power sharing among the DGs, voltage regulation and frequency deviation. The results validate the advantages of the proposed methodology as compared to traditional droop control of AC microgrid. The DCC-based control methodology for AC microgrid and DC microgrid are further expanded to develop a DCC-based power management algorithm for hybrid AC/DC microgrid. The developed algorithm for hybrid microgrid controls the power flow through the interfacing converter (IC) between the AC and DC microgrids. This will facilitate the power sharing between the DGs according to their power ratings. Moreover, it enables the fixed scheduled power delivery at different operating conditions, while maintaining good voltage regulation and improved frequency profile. The second section provides a detailed explanation and step-by-step design and development of an AC/DC microgrid testbed. Controllers for the three-phase inverters are designed and tested on different generation units along with their corresponding inductor-capacitor-inductor (LCL) filters to eliminate the switching frequency harmonics. Electric power distribution line models are developed to form the microgrid network topology. Voltage and current sensors are placed in the proper

  5. Estimation of luminescence lifetime in frequency domain

    Institute of Scientific and Technical Information of China (English)

    Zhang Fu-Jun; Xu Zheng; Zhao Su-Ling; Lou Zhi-Dong; Yang Sheng-Yi; Xu Xu-Rong

    2006-01-01

    Absorption is the origin of luminescence. But it must be noticed that the lifetime of luminescence might reversely influence the rate of absorption. In this paper, it is reported that the luminescence intensity of copper and manganese changes with the driving frequency at constant voltage. The variation of luminescent intensity depends only on the lifetime of luminescence but not on the type of quenching or other factors. Generally the rate of absorption is dominantly determined by the material property and the lifetime of luminescence centres, the absorption of shorter lifetime centre will be larger than that of the longer lifetime centre at the same excited condition.

  6. Temperature-controlled down-conversion luminescence behavior of Eu(3)(+) -doped transparent MF2 (M = Ba, Ca, Sr) glass ceramics.

    Science.gov (United States)

    Zhou, B; E, C Q; Bu, Y Y; Meng, L; Yan, X H; Wang, X F

    2017-03-01

    Eu(3)(+) -doped transparent glass ceramics containing MF2 (M = Ba, Ca, Sr) nanocrystals were fabricated using a melt-quenching method, and the resulting structures were studied using X-ray diffraction. Levels (5) D1 and (5) D0 of Eu(3)(+) ions were verified as thermally coupled levels using the fluorescence intensity ratio method. The fluorescence intensity ratios, optical temperature sensitivity and thermal quenching ratios of the transparent glass ceramics were studied as a function of temperature. With an increase in temperature, the relative sensitivity (SR ) decreased sharply at first, then slowly increased, before finally decreasing. The minimum SR values of GCBaF2 (GCB), GCCaF2 (GCC) and GCSrF2 (GCS) were 2.8 × 10(-4) , 0.8 × 10(-4) and 1.9 × 10(-)(4)  K(-1) at 360, 269 and 319 K, respectively. Glass ceramics with an intense emission intensity can be used to convert the measured spectrum into temperature and may have an important role in temperature detectors. Copyright © 2016 John Wiley & Sons, Ltd.

  7. Bimodal Imaging Using Neodymium Doped Gadolinium Fluoride Nanocrystals with Near-Infrared to Near-Infrared Downconversion Luminescence and Magnetic Resonance Properties

    OpenAIRE

    Mimun, L. Christopher; Ajithkumar, Gangadharan; Pokhrel, Madhab; Yust, Brian G.; Elliott, Zak G.; Pedraza, Francisco; Dhanale, Ashish; Tang, Liang; Lin, Ai-Ling; Dravid, Vinayak P.; Sardar, Dhiraj K.

    2013-01-01

    Here we report the synthesis, characterization and application of a multifunctional surface functionalized GdF3:Nd3+ nanophosphor that exhibits efficient near infrared (NIR) fluorescence as well as magnetic properties, which can be utilized for bimodal imaging in medical applications. The nanoparticles are small with an average size of 5 nm and form stable colloids that last for several weeks without settling, enabling the use for several biomedical and photonic applications. Their excellent ...

  8. Instant luminescence chronologies? High resolution luminescence profiles using a portable luminescence reader

    OpenAIRE

    Bateman, M. D.; Stein, S.; Ashurst, R.A.; Selby, K.

    2015-01-01

    Establishing a robust chronology is fundamental to most palaeoenvironmental studies. However, the number and positioning of dated points is critical. Using a portable luminescence reader, it is possible to rapidly generate high resolution down core relative age profiles. Profiles of portable luminescence data from two coastal dunes were evaluated and compared with the results of particle size analysis, stratigraphy, and an independent historical chronology. Results show that, even in young sa...

  9. Regional higher education co-operation: a research proposal to compare the Baltic Sea and the Black Sea regions

    Directory of Open Access Journals (Sweden)

    Stefan Ewert

    2011-12-01

    Full Text Available While the Baltic Sea Region is considered to be a pioneer region in the development of regional integration and identity, the Black Sea Region is regarded to be a laggard in terms of regionali¬zation and region building. My paper summarizes the role of regional higher education co-operation in the Baltic Sea regionalization process in theory and analyzes the empirical background of these assumptions. Yet, inasmuch an evaluation of the regions` status as a pioneer is possible only in a comparative perspective, I propose to compare the Black Sea and the Baltic Sea Region regarding their higher education networks systematically. My paper asks for the transferability of arguments in favor of a strong regional higher education co-operation in the Baltic Sea Region since the 1990s to today’s situation of the Black Sea Region. It concludes with some fundamental considerations on a comparative research project.

  10. Nanophotonics and nanochemistry: controlling the excitation dynamics for frequency up- and down-conversion in lanthanide-doped nanoparticles.

    Science.gov (United States)

    Chen, Guanying; Yang, Chunhui; Prasad, Paras N

    2013-07-16

    Nanophotonics is an emerging science dealing with the interaction of light and matter on a nanometer scale and holds promise to produce new generation nanophosphors with highly efficient frequency conversion of infrared (IR) light. Scientists can control the excitation dynamics by using nanochemistry to produce hierarchically built nanostructures and tailor their interfaces. These nanophosphors can either perform frequency up-conversion from IR to visible or ultraviolet (UV) or down-conversion, which results in the IR light being further red shifted. Nanophotonics and nanochemistry open up numerous opportunities for these photon converters, including in high contrast bioimaging, photodynamic therapy, drug release and gene delivery, nanothermometry, and solar cells. Applications of these nanophosphors in these directions derive from three main stimuli. Light excitation and emission within the near-infrared (NIR) "optical transparency window" of tissues is ideal for high contrast in vitro and in vivo imaging. This is due to low natural florescence, reduced scattering background, and deep penetration in tissues. Secondly, the naked eye is highly sensitive in the visible range, but it has no response to IR light. Therefore, many scientists have interest in the frequency up-conversion of IR wavelengths for security and display applications. Lastly, frequency up-conversion can convert IR photons to higher energy photons, which can then readily be absorbed by solar materials. Current solar devices do not use abundant IR light that comprises almost half of solar energy. In this Account, we present our recent work on nanophotonic control of frequency up- and down-conversion in fluoride nanophosphors, and their biophotonic and nanophotonic applications. Through nanoscopic control of phonon dynamics, electronic energy transfer, local crystal field, and surface-induced non-radiative processes, we were able to produce new generation nanophosphors with highly efficient frequency

  11. Inter-Firm Co-Operative Strategies In The Context Of Discontinuous Technological Change. The Case Of The Uk Optical Communications Systems Industry

    NARCIS (Netherlands)

    S. Spedale-Latimer (Simona)

    2002-01-01

    textabstractAt times of discontinuous technological change co-operation represents a viable strategy for both incumbents and new-entrants, provided that the choice of co-operation is consistent with the firm's business strategy (market-pull vs. technology-push) and with its degree of organizational

  12. Inter-Firm Co-Operative Strategies In The Context Of Discontinuous Technological Change. The Case Of The Uk Optical Communications Systems Industry

    NARCIS (Netherlands)

    S. Spedale-Latimer (Simona)

    2002-01-01

    textabstractAt times of discontinuous technological change co-operation represents a viable strategy for both incumbents and new-entrants, provided that the choice of co-operation is consistent with the firm's business strategy (market-pull vs. technology-push) and with its degree of organizational

  13. Co-operation between employee and management to increase productivity: : a case study of Mobil Producing Nigeria Unlimited

    OpenAIRE

    Okafor, Oluchi

    2013-01-01

    Laurea University of Applied Sciences Abstract Laurea Leppävaara Bachelor’s Degree Programme in Business Management Okafor Oluchi Co-operation between employee and management to increase productivity: a case study of Mobil Producing Nigeria Unlimited. The purpose of this thesis is to carry out research on the effect of the management and employee relationship on productivity in an organization. This thesis project uses Mobil producing Nigeria Unlimited, a subsidiary of Exx...

  14. Climate protection in Germany`s bilateral development co-operation with the People`s Republic of China

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, A.

    1996-12-31

    For globally sustainable development to be achieved, three concerns are central: productive economic growth, social justice and ecological sustainability. Development co-operation supports the realisation of these three goals in partner countries by helping to alleviate poverty, promote economic growth through private-sector development and protect vital natural resources. The aim of globally sustainable development can only be achieved if industrial countries too implement necessary reforms and structural adjustments at every level. Co-operation efforts with partners must therefore be complemented by coherent policies at home. This is a matter of credibility, but also of developmental far-sightedness. Internal reforms in the industrial countries secure financial leeway for their providing foreign assistance in the longer term. Environmental and resource protection as a focal point of Germany`s development co-operation with the PRC aims to preserve vital natural resources, shape economic development in their partner countries in an ecologically sound manner and put China in a position to participate in global endeavours to protect the environment. Climate protection measures figure prominently in this area. This is justified given China`s share of global CO{sub 2} emissions and the potential for energy-saving measures and measures to increase power intensity. This potential is derived primarily from the possibility of using energy-efficient technologies, increasing the relatively low energy prices and making use of renewable sources of energy.

  15. Detecting the origin of luminescence in Er3+-doped hexagonal Nasub>1.5sub>Gdsub>1.5sub>Fsub>6sub> phosphors.

    Science.gov (United States)

    Wang, Xiangfu; Bu, Yanyan; Yan, Xiaohong; Cai, Peiqing; Wang, Jing; Qin, Lin; Vu, Thiquynh; Seo, Hyo Jin

    2016-11-15

    Understanding site-selective fluorescence is one of valuable importance for spectrum modulation. In this Letter, we observed the existence of two non-equivalent Gd-activated crystallographic sites in an Er3+-doped hexagonal Nasub>1.5sub>Gdsub>1.5sub>Fsub>6sub> phosphor. It is proved that two green emissions from the Ssub>3/2sub>4 level separately originate from the Gd1 (540 nm) and Na2/Gd2 (550-555 nm) crystallographic sites, and the 657 nm red emission from the Fsub>9/2sub>4 level only originates from Na2/Gd2 site through using the time-resolved luminescence spectra. The 142.2% absolute enhancement of the red emission is realized through the synergistic effect of ultraviolet downconversion and infrared upconversion induced by the 370 nm and 1.54 μm dual-mode excitation.

  16. Enhanced photoelectric conversion efficiency of dye sensitized solar cells via the incorporation of one dimensional luminescent BaWO4:Eu(3+) nanowires.

    Science.gov (United States)

    Wang, Yuping; Qu, Yang; Pan, Kai; Wang, Guofeng; Li, Yadong

    2016-09-25

    One dimensional hierarchical BaWO4:Eu(3+) nanowires have been prepared via a hydrothermal method for the first time. The obtained BaWO4:Eu(3+) nanowires are not only a promising down-conversion luminescence material, but also can be used to improve the efficiency of dye sensitized solar cells, resulting an efficiency of 7.66%, which is a noticeable enhancement of 15% compared to the cell without BaWO4:Eu(3+) nanowires. We suggest that the enhancement of the efficiencies of the TiO2-BaWO4:Eu(3+) composite cells was mainly related to the light scattering of BaWO4:Eu(3+).

  17. Higher-order spontaneous parametric down-conversion with back-propagating idler using a submicron poled KTP waveguide

    Science.gov (United States)

    Bashkansky, Mark; Pruessner, Marcel W.; Vurgaftman, Igor; Kim, Mijin; Reintjes, J.

    2016-05-01

    Spontaneous parametric downconversion (SPDC) using periodically poled nonlinear optical crystals under the quasiphase- matching condition has found wide use in quantum optics. High efficiencies and good coupling to single-mode fibers resulted from using channel waveguides in crystals. It is often desirable to have a very narrow bandwidth for the signal and idler photons, but under the typical operating conditions, phase matching dictates the bandwidth of the SPDC to be of the order of inversion on the wavelength scale is required. In this work, we experimentally demonstrate SPDC in one-dimensional KTP-based waveguides with sub-micron poling for forward and backward interactions. Some of the spectral features of the generated light are accounted for by mode coupling theory in periodically poled waveguides but other features are as yet not explained.

  18. Telecom-band two-photon Michelson interferometer using frequency entangled photon pairs generated by spontaneous parametric down-conversion

    Science.gov (United States)

    Yoshizawa, Akio; Fukuda, Daiji; Tsuchida, Hidemi

    2014-02-01

    We demonstrate a telecom-band fiber-optic two-photon Michelson interferometer using near-degenerate and collinear photon pairs with frequency entanglement. For spontaneous parametric down-conversion (SPDC), a continuous-wave laser diode pumps a periodically poled lithium niobate waveguide. Two threshold single-photon detectors record coincidence counts to observe two-photon interference and evaluate the correlation function. Multi-pair emission events are inevitable in SPDC and photon pairs without frequency entanglement are unintentionally registered as coincidence counts. In the demonstrated experiment, a mixture of photon pairs with and without frequency entanglement is present. The effects of such a mixed state on the correlation function are experimentally investigated. Two-photon interference of photon pairs without frequency entanglement is also measured for comparison.

  19. Entanglement and nonclassicality in four-mode Gaussian states generated via parametric down-conversion and frequency up-conversion

    Science.gov (United States)

    Arkhipov, Ievgen I.; Peřina, Jan, Jr.; Haderka, Ondřej; Allevi, Alessia; Bondani, Maria

    2016-09-01

    Multipartite entanglement and nonclassicality of four-mode Gaussian states generated in two simultaneous nonlinear processes involving parametric down-conversion and frequency up-conversion are analyzed assuming the vacuum as the initial state. Suitable conditions for the generation of highly entangled states are found. Transfer of the entanglement from the down-converted modes into the up-converted ones is also suggested. The analysis of the whole set of states reveals that sub-shot-noise intensity correlations between the equally-populated down-converted modes, as well as the equally-populated up-converted modes, uniquely identify entangled states. They represent a powerful entanglement identifier also in other cases with arbitrarily populated modes.

  20. Heralded quantum repeater based on the scattering of photons off single emitters using parametric down-conversion source.

    Science.gov (United States)

    Song, Guo-Zhu; Wu, Fang-Zhou; Zhang, Mei; Yang, Guo-Jian

    2016-06-28

    Quantum repeater is the key element in quantum communication and quantum information processing. Here, we investigate the possibility of achieving a heralded quantum repeater based on the scattering of photons off single emitters in one-dimensional waveguides. We design the compact quantum circuits for nonlocal entanglement generation, entanglement swapping, and entanglement purification, and discuss the feasibility of our protocols with current experimental technology. In our scheme, we use a parametric down-conversion source instead of ideal single-photon sources to realize the heralded quantum repeater. Moreover, our protocols can turn faulty events into the detection of photon polarization, and the fidelity can reach 100% in principle. Our scheme is attractive and scalable, since it can be realized with artificial solid-state quantum systems. With developed experimental technique on controlling emitter-waveguide systems, the repeater may be very useful in long-distance quantum communication.

  1. Efficient light harvesting by photon downconversion and light trapping in hybrid ZnS nanoparticles/Si nanotips solar cells.

    Science.gov (United States)

    Huang, Chun-Ying; Wang, Di-Yan; Wang, Chun-Hsiung; Chen, Yung-Ting; Wang, Yaw-Tyng; Jiang, You-Ting; Yang, Ying-Jay; Chen, Chia-Chun; Chen, Yang-Fang

    2010-10-26

    A hybrid colloidal ZnS nanoparticles/Si nanotips p-n active layer has been demonstrated to have promising potential for efficient solar spectrum utilization in crystalline silicon-based solar cells. The hybrid solar cell shows an enhancement of 20% in the short-circuit current and approximately 10% in power conversion efficiency compared to its counterpart without integrating ZnS nanoparticles. The enhancement has been investigated by external quantum efficiency, photoluminescence excitation spectrum, photoluminescence, and reflectance to distinct the role of ZnS quantum dots for light harvesting. It is concluded that ZnS nanoparticles not only act as frequency downconversion centers in the ultraviolet region but also serve as antireflection coating for light trapping in the measured spectral regime. Our approach is ready to be extended to many other material systems for the creation of highly efficient photovoltaic devices.

  2. Third-order spontaneous parametric down-conversion in thin optical fibers as a photon-triplet source

    Energy Technology Data Exchange (ETDEWEB)

    Corona, Maria [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, apdo. postal 70-543, DF 04510 Mexico City (Mexico); Departamento de Optica, Centro de Investigacion Cientifica y de Educacion Superior de Ensenada, Apartado Postal 2732, BC 22860 Ensenada (Mexico); Garay-Palmett, Karina; U' Ren, Alfred B. [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, apdo. postal 70-543, DF 04510 Mexico City (Mexico)

    2011-09-15

    We study the third-order spontaneous parametric down-conversion (TOSPDC) process, as a means to generate entangled photon triplets. Specifically, we consider thin optical fibers as the nonlinear medium to be used as the basis for TOSPDC in configurations where phase matching is attained through the use of more than one fiber transverse modes. Our analysis in this paper, which follows from our earlier paper [Opt. Lett. 36, 190-192 (2011)], aims to supply experimentalists with the details required in order to design a TOSPDC photon-triplet source. Specifically, our analysis focuses on the photon triplet state, on the rate of emission, and on the TOSPDC phase-matching characteristics for the cases of frequency-degenerate and frequency nondegenerate TOSPDC.

  3. Fluorescent MoS2 Quantum Dots: Ultrasonic Preparation, Up-Conversion and Down-Conversion Bioimaging, and Photodynamic Therapy.

    Science.gov (United States)

    Dong, Haifeng; Tang, Songsong; Hao, Yansong; Yu, Haizhu; Dai, Wenhao; Zhao, Guifeng; Cao, Yu; Lu, Huiting; Zhang, Xueji; Ju, Huangxian

    2016-02-10

    Small size molybdenum disulfide (MoS2) quantum dots (QDs) with desired optical properties were controllably synthesized by using tetrabutylammonium-assisted ultrasonication of multilayered MoS2 powder via OH-mediated chain-like Mo-S bond cleavage mode. The tunable up-bottom approach of precise fabrication of MoS2 QDs finally enables detailed experimental investigations of their optical properties. The synthesized MoS2 QDs present good down-conversion photoluminescence behaviors and exhibit remarkable up-conversion photoluminescence for bioimaging. The mechanism of the emerging photoluminescence was investigated. Furthermore, superior (1)O2 production ability of MoS2 QDs to commercial photosensitizer PpIX was demonstrated, which has great potential application for photodynamic therapy. These early affording results of tunable synthesis of MoS2 QDs with desired photo properties can lead to application in fields of biomedical and optoelectronics.

  4. Entanglement and nonclassicality in four-mode Gaussian states generated via parametric down-conversion and frequency up-conversion

    Science.gov (United States)

    Arkhipov, Ievgen I.; Peřina Jr., Jan; Haderka, Ondřej; Allevi, Alessia; Bondani, Maria

    2016-01-01

    Multipartite entanglement and nonclassicality of four-mode Gaussian states generated in two simultaneous nonlinear processes involving parametric down-conversion and frequency up-conversion are analyzed assuming the vacuum as the initial state. Suitable conditions for the generation of highly entangled states are found. Transfer of the entanglement from the down-converted modes into the up-converted ones is also suggested. The analysis of the whole set of states reveals that sub-shot-noise intensity correlations between the equally-populated down-converted modes, as well as the equally-populated up-converted modes, uniquely identify entangled states. They represent a powerful entanglement identifier also in other cases with arbitrarily populated modes. PMID:27658508

  5. High dynamic range microwave photonic down-conversion based on dual-parallel Mach-Zehnder modulator

    Science.gov (United States)

    Li, Hongli; Wang, Yunxin; Wang, Dayong; Rong, Lu; Jia, Yupeng; Li, Jingnan; Zhong, Xin; Yang, Dengcai; Zhou, Tao

    2016-10-01

    In order to enhance conversion efficiency and spurious free dynamic range of microwave photonic link, we present a microwave photonic down-conversion system based on an integrated dual-parallel Mach Zehnder modulator (DPMZM) and microwave photonic filter. The principle of frequency down conversion is analyzed. We demonstrate the conversion efficiency of system through theoretical derivation and simulation. The performance of the microwave photonic link is tested experimentally. It is found that the spurious free dynamic range of the proposed method is up to 102.5dB/Hz2/3 and the conversion efficiency is up to -22.01dB. The integrated dual-parallel Mach-Zehnder modulator link can serve as a good alternative to improve the conversion efficiency and spurious free dynamic range.

  6. Turning on the Light: Lessons from Luminescence

    Science.gov (United States)

    O'Hara, Patricia B.; Engelson, Carol; St. Peter, Wayne

    2005-01-01

    Some of the processes by which light is emitted without a simultaneous change in temperature are discussed and is classified as luminescence or cold light. Luminescent processes include triboluminescence, fluorescence, phosphorescence, chemiluminescence, and bioluminescence.

  7. The Contribution Of Co-Operative Education In The Growing Of Talent In South Africa: A Qualitative Phenomenological Exploration

    Directory of Open Access Journals (Sweden)

    Thomas Groenewald

    2003-11-01

    Full Text Available Organisational talent is internationally regarded a key success factor in a competitive world and is continuously challenged. In South Africa, the Apartheid heritage further presents major challenges regarding developmental opportunities of talented people. Co-operative education presents, as structured educational strategy that progressively integrates academic study with learning through productive work experiences, itself as a means to grow the talent of the South African people. As result of the inadequate practice of co-operative education and a fair amount of associated resistance, ‘classical’ literature is reviewed. The literature review further identifies the core properties of co-operative education and the study has attempted to distil the core principles of a phenomenological research design. The specific ‘phenomena’ which the research focused on are existing joint ventures between Higher Education institutions and business enterprises aimed at educating people and growing talent. Selections of the voices of the research participants are presented in this article. Although the present study identifies several shortcomings regarding the practice of co-operative education, it pioneers the notion that the growing of talent can be enhanced through a co-operative education strategy. OpsommingOrganisatoriese talent word internasionaal beskou as ’n sleutelfaktor in ’n kompeterende wêreld en word dus voortdurend aan uitdagings onderwerp. In Suid Afrika stel die nagevolge van Apartheid grootskaalse uitdagings ten opsigte van die ontwikkelings moontlikhede van talentvolle mense. Koöperatiewe onderwys bied, as gestruktureerde opvoedkundige strategie wat progressief akademiese leer met produktiewe werkservaring integreer, ’n geleentheid om die talent van Suid-Afrikaners op te bou. ‘Klasieke’ literatuur word weegegee ten einde die ontoereikende beoefening van koöperatiewe onderwys en ’n gepaartgaande redelike mate van

  8. 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...

  9. Method of measuring luminescence of a material

    Science.gov (United States)

    Miller, Steven D.

    2015-12-15

    A method of measuring luminescence of a material is disclosed. The method includes applying a light source to excite an exposed material. The method also includes amplifying an emission signal of the material. The method further includes measuring a luminescent emission at a fixed time window of about 10 picoseconds to about 10 nanoseconds. The luminescence may be radio photoluminescence (RPL) or optically stimulated luminescence (OSL).

  10. Self absorption in luminescent solar concentrators

    NARCIS (Netherlands)

    Krumer, Z.

    2014-01-01

    Luminescent solar concentrators are photovoltaic devices made of thin transparent material, in which luminescent particles are dispersed. The incident light enters the device through its large facets and is subsequently absorbed by the luminescent particles, which re-emit it whilst changing its dire

  11. A luminescent nanocrystal stress gauge

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Charina; Koski, Kristie; Olson, Andrew; Alivisatos, Paul

    2010-10-25

    Microscale mechanical forces can determine important outcomes ranging from the site of material fracture to stem cell fate. However, local stresses in a vast majority of systems cannot be measured due to the limitations of current techniques. In this work, we present the design and implementation of the CdSe/CdS core/shell tetrapod nanocrystal, a local stress sensor with bright luminescence readout. We calibrate the tetrapod luminescence response to stress, and use the luminescence signal to report the spatial distribution of local stresses in single polyester fibers under uniaxial strain. The bright stress-dependent emission of the tetrapod, its nanoscale size, and its colloidal nature provide a unique tool that may be incorporated into a variety of micromechanical systems including materials and biological samples to quantify local stresses with high spatial resolution.

  12. Micro-modulated luminescence tomography

    CERN Document Server

    Cong, Wenxiang; Wang, Chao; Wang, Ge

    2013-01-01

    Imaging depth of optical microscopy has been fundamentally limited to millimeter or sub-millimeter due to light scattering. X-ray microscopy can resolve spatial details of few microns deeply inside a sample but the contrast resolution is still 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 the subsequently stimulated luminescence emission by visible/near-infrared (NIR) light. In this paper, we suggest a micro-modulated luminescence tomography (MLT) approach to quantify a nanophosphor distribution in a thick biological sample with high resolution. Our numerical simulation studies demonst...

  13. Quantitative luminescence imaging system

    Science.gov (United States)

    Batishko, C. R.; Stahl, K. A.; Fecht, B. A.

    The goal of the Measurement of Chemiluminescence project is to develop and deliver a suite of imaging radiometric instruments for measuring spatial distributions of chemiluminescence. Envisioned deliverables include instruments working at the microscopic, macroscopic, and life-sized scales. Both laboratory and field portable instruments are envisioned. The project also includes development of phantoms as enclosures for the diazoluminomelanin (DALM) chemiluminescent chemistry. A suite of either phantoms in a variety of typical poses, or phantoms that could be adjusted to a variety of poses, is envisioned. These are to include small mammals (rats), mid-sized mammals (monkeys), and human body parts. A complete human phantom that can be posed is a long-term goal of the development. Taken together, the chemistry and instrumentation provide a means for imaging rf dosimetry based on chemiluminescence induced by the heat resulting from rf energy absorption. The first delivered instrument, the Quantitative Luminescence Imaging System (QLIS), resulted in a patent, and an R&D Magazine 1991 R&D 100 award, recognizing it as one of the 100 most significant technological developments of 1991. The current status of the project is that three systems have been delivered, several related studies have been conducted, two preliminary human hand phantoms have been delivered, system upgrades have been implemented, and calibrations have been maintained. Current development includes sensitivity improvements to the microscope-based system; extension of the large-scale (potentially life-sized targets) system to field portable applications; extension of the 2-D large-scale system to 3-D measurement; imminent delivery of a more refined human hand phantom and a rat phantom; rf, thermal and imaging subsystem integration; and continued calibration and upgrade support.

  14. 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

  15. Multicolored luminescent CdS nanocrystals

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The observation of efficient blue, green, orange and red luminescence from CdS nanocrystals made by using a reverse micelle method was reported. The blue luminescence about 480 nm is attributed to the radiative recombination of electron-hole pairs.The red luminescence around 650 nm is due to the radiative recombination of the exciton trapped in the nanocrystal surface defect states. The combination of different portion of band-edge emission and surface trap state emission results in green and orange luminescence for the nanocrystals. The CdS nanocrystals with efficient multicolored luminescence may find potential application in full color displays and biolabelings.

  16. Efficient dual mode multicolor luminescence in a lanthanide doped hybrid nanostructure: a multifunctional material.

    Science.gov (United States)

    Singh, S K; Singh, A K; Rai, S B

    2011-07-08

    The present work deals with inorganic-organic hybrid nanostructures capable of producing intense visible emission via upconversion (UC), downconversion (DC), and energy transfer (ET) processes which show the potential of the material as a luminescent solar collector (LSC), particularly to improve the efficiency of silicon solar cells. To achieve this, Gd2O3:Yb3+/Er3+ phosphor (average particle size∼35 nm) and a Eu(DBM)3Phen organic complex have been synthesized separately and then the hybrid structure has been developed using a simple mixing procedure. Intense UC emission (in the red, green, and blue regions) due to Er3+ is observed on near infrared (976 nm) excitation which shows color tunability with input pump power. In contrast, intense red emission of Eu3+ is observed on ultaviolet (UV) (355 nm) excitation. The feasibility of energy transfer from Er3+ ions to Eu3+ ions has also been noted. These excellent optical properties are retained even if the particles of the hybrid nanostructure are dispersed in liquid medium, which also makes it suitable for security ink purposes.

  17. Analysis on the Load Carrying Mechanism Integrated as Heterogeneous Co-operative Manipulator in a Walking Wheelchair

    Science.gov (United States)

    Rajay Vedaraj, I. S.; Jain, Ritika; Rao, B. V. A.

    2014-07-01

    After industrial robots came into existence during 1960, the technology of robotics with the design and analysis of robots in various forms in industries as well as in domestic applications were developed. Nowadays, along with the automotive sector the robots are producing a great impact in the form of quality and production rate to register their existence reliable in various other sectors also. Robotic technology has undergone various phase translations from being tortured as humanoids to the present day manipulators. Depending upon the various forms of its existence, robot manipulators are designed as serial manipulators and parallel manipulators. Individually both types can be proved effective though both have various drawbacks in design and the kinematic analysis. The versatility of robots can be increased by making them work in an environment where the same work volume is shared by more than one manipulator. This work volume can be identified as co-operative work volume of those manipulators. Here the interference of manipulators in the work volume of other manipulators is possible and is made obstacle free. The main advantage of co-operative manipulators is that when a number of independent manipulators are put together in a cooperative work envelope the efficiency and ability to perform tasks is greatly enhanced. The main disadvantage of the co-operative manipulators lies in the complication of its design even for a simple application, in almost all fields. In this paper, a cooperative design of robot manipulators to work in co-operative work environment is done and analysed for its efficacy. In the industrial applications when robotic manipulators are put together in more numbers, the trajectory planning becomes the tough task in the work cell. Proper design can remove the design defects of the cooperative manipulators and can be utilized in a more efficient way. In the proposed research paper an analysis is made on such a type of cooperative manipulator

  18. LTI system order reduction approach based on asymptotical equivalence and the Co-operation of biology-related algorithms

    Science.gov (United States)

    Ryzhikov, I. S.; Semenkin, E. S.; Akhmedova, Sh A.

    2017-02-01

    A novel order reduction method for linear time invariant systems is described. The method is based on reducing the initial problem to an optimization one, using the proposed model representation, and solving the problem with an efficient optimization algorithm. The proposed method of determining the model allows all the parameters of the model with lower order to be identified and by definition, provides the model with the required steady-state. As a powerful optimization tool, the meta-heuristic Co-Operation of Biology-Related Algorithms was used. Experimental results proved that the proposed approach outperforms other approaches and that the reduced order model achieves a high level of accuracy.

  19. European tendencies and co-operation in the field of ITS systems - national achievements and challenges in Hungary

    Science.gov (United States)

    Lindenbach, Ágnes

    2016-06-01

    The article presents the role of intelligent transport systems/services related to the implementation of the essential European and Hungarian transport policy objectives. The `ITS Directive' will provide a framework for the tasks/works to be performed in the forthcoming years within the priority areas of ITS. The European Commission published regulations / specifications for the priority actions in the form of delegated acts defining the tasks/responsibilities of Member States. Regional/European co-operation for Hungary started after the EU-accession of the country. Hungary was an active partner within the European CONNECT and EasyWay projects, currently Hungary is a member of the CROCODILE consortium.

  20. The biaxial nonlinear crystal BiB3O6 as a polarization entangled photon source using non-collinear type-II parametric down-conversion

    CERN Document Server

    Halevy, A; Dovrat, L; Eisenberg, H S; Becker, P; Bohatý, L

    2011-01-01

    We describe the full characterization of the biaxial nonlinear crystal BiB3O6 (BiBO) as a polarization entangled photon source using non-collinear type-II parametric down-conversion. We consider the relevant parameters for crystal design, such as cutting angles, polarization of the photons, effective nonlinearity, spatial and temporal walk-offs, crystal thickness and the effect of the pump laser bandwidth. Experimental results showing entanglement generation with high rates and a comparison to the well investigated beta-BaB2O4 (BBO) crystal are presented as well. Changing the down-conversion crystal of a polarization entangled photon source from BBO to BiBO enhances the generation rate as if the pump power was increased by more than three times. Such an improvement is currently required for the generation of multiphoton entangled states.

  1. The biaxial nonlinear crystal BiB₃O₆ as a polarization entangled photon source using non-collinear type-II parametric down-conversion.

    Science.gov (United States)

    Halevy, A; Megidish, E; Dovrat, L; Eisenberg, H S; Becker, P; Bohatý, L

    2011-10-10

    We describe the full characterization of the biaxial nonlinear crystal BiB₃O₆ (BiBO) as a polarization entangled photon source using non-collinear type-II parametric down-conversion. We consider the relevant parameters for crystal design, such as cutting angles, polarization of the photons, effective nonlinearity, spatial and temporal walk-offs, crystal thickness and the effect of the pump laser bandwidth. Experimental results showing entanglement generation with high rates and a comparison to the well investigated β-BaB₂O₄ (BBO) crystal are presented as well. Changing the down-conversion crystal of a polarization entangled photon source from BBO to BiBO enhances the generation rate as if the pump power was increased by 2.5 times. Such an improvement is currently required for the generation of multiphoton entangled states.

  2. Measurement of SFDR and noise in EDF amplified analog RF links using all-optical down-conversion and balanced receivers

    Science.gov (United States)

    Middleton, Charles; Borbath, Michael; Wyatt, Jeff; DeSalvo, Richard

    2008-04-01

    Optical down-conversion techniques have become an increasingly popular architecture to realize Multi-band Enterprise Terminals (MET), Synthetic Aperture Radar (SAR), Optical Arbitrary Waveform Generation (OAWG), RF Channelizers and other technologies that need rapid frequency agile tunability in the microwave and millimeter RF bands. We describe recent SFDR, NF, Gain, and Noise modeling and measurements of Erbium-doped-fiber amplified analog RF optical links implementing all-optical down-conversion and balanced photodiode receivers. We describe measurements made on our newly designed extensive test-bed utilizing a wide array of high powered single and balanced photodiodes, polarization preserving output LN modulators, EAMs, LIMs, tunable lasers, EDFAs, RF Amplifiers, and other components to fully characterize direct and coherent detection techniques. Additionally, we compare these experimental results to our comprehensive MATLAB system modeling and optimization software tools.

  3. Four-mode continuous-variables entangled state:generation from beam splitter, a parametric down-conversion and a polarizer

    Institute of Scientific and Technical Information of China (English)

    Kuang Mai-Hua; Ma Shan-Jun; Liu Dong-Mei; Wang Shu-Jing

    2009-01-01

    We introduce a new kind of four-mode continuous variable entangled state in Fock space. The completeness relation and the partly nonorthonormal property of such a state are proven. The scheme to generate this state is presented by combining a symmetrical beamsplitter, a parametric down-conversion and a polarizer. After making a single-mode quadrature amplitude measurement, the remaining three modes are kept in entanglement. And its applications are also discussed.

  4. 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...

  5. Controlling plasmon-enhanced luminescence

    NARCIS (Netherlands)

    Mertens, H.

    2007-01-01

    Plasmons are collective oscillations of the free electrons in a metal or an ionized gas. Plasmons dominate the optical properties of noble-metal nanoparticles, which enables a variety of applications. This thesis focuses on plasmon-enhanced luminescence of silicon quantum dots (Si QDs) and optically

  6. High efficiency white luminescence in Tm{sup 3+}/Er{sup 3+}/Yb{sup 3+} tri-doped oxyfluoride glass ceramic microsphere pumped by 976 nm laser

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Jing; Huang, Yantang, E-mail: huangyantang@fzu.edu.cn; Wu, Tianjiao; Huang, Yu; Zhang, Peijin

    2015-01-15

    In this paper, transparent Tm{sup 3+}/Er{sup 3+}/Yb{sup 3+} tri-doped oxyfluoride glass ceramic samples containing LaF{sub 3} nanocrystals were prepared by a melt quenching method, and were subsequently fabricated into transparent microspheres with handles. A new method to study the luminescent properties of Tm{sup 3+}/Er{sup 3+}/Yb{sup 3+} tri-doped oxyfluoride glass ceramic was proposed, which was using the biconical tapered fiber-microsphere coupled structure. The structure has characteristics of low excitation optical power, easy preparation and convenient testing. We obtained strong white light including the blue (471 nm), green (523 nm and 544 nm) and red (651 nm) emission under the excitation of a 976 nm laser diode (LD) and the relationship of the luminous flux of white light versus pump power simultaneously. In addition, the up-conversion (UC) luminescence mechanism of rare earth (RE) ions and the reason of high luminescence efficiency in our experiment were also explained. The white light obtained by UC of 976 nm laser has more advantages than that by down-conversion of blue light. It may be applied in many fields such as background light, lighting, etc. - Highlights: • A new method to study the luminescent properties of glass materials is proposed. • The white light was obtained by up-conversion of 976 nm laser. • The mechanism of up-conversion luminescence was clearly explained. • The advantages of the white luminescence excited by 976 nm were reported.

  7. On observation of the downconversion mechanism in Er{sup 3+}/Yb{sup 3+} co-doped tellurite glass using thermal and optical parameters

    Energy Technology Data Exchange (ETDEWEB)

    Figueiredo, M.S.; Santos, F.A. [Universidade Federal da Grande Dourados, Faculdade de Ciências Exatas e Tecnologias, Dourados, MS (Brazil); Yukimitu, K.; Moraes, J.C.S. [Universidade Estadual Paulista, UNESP, Departamento de Física e Química, Av. Brasil, 56, 15385-000 Ilha Solteira, SP (Brazil); Nunes, L.A.O. [Instituto de Física de São Carlos, Universidade de São Paulo, CP 369, 13560-970 São Carlos, SP (Brazil); Andrade, L.H.C. [Grupo de Espectroscopia Óptica e Fototérmica, Universidade Estadual de Mato Grosso do Sul, Cidade Universitária de Dourados, CP 351, Dourados, MS (Brazil); Lima, S.M., E-mail: smlima@uems.br [Grupo de Espectroscopia Óptica e Fototérmica, Universidade Estadual de Mato Grosso do Sul, Cidade Universitária de Dourados, CP 351, Dourados, MS (Brazil)

    2015-01-15

    In this work we report the observed downconversion (DC) mechanism in Er{sup 3+}/Yb{sup 3+}-codoped tellurite glasses (in mol%, 80TeO{sub 2}–10Li{sub 2}O–10TiO{sub 2}). The samples were synthesized by the conventional melt-quenching method and then studied using optical spectroscopy and thermal lens spectroscopy (TLS). These characterizations enabled investigation of the radiative and nonradiative processes involved in energy transfer from erbium to ytterbium. The visible Er{sup 3+} fluorescence intensities decreased as a function of the Yb{sup 3+} concentration, and there was a corresponding increase in the ytterbium emission at around 980 nm. Simultaneously, there was a reduction in the heat-generated due nonradiative decays (∼21%) when ytterbium was added. This temperature change was measured by TLS measurements and the results corroborate with the indicated by spectroscopic interpretation. - Highlights: • Energy transfer from erbium to ytterbium in tellurite glass. • ∼56% of cross-relaxation efficiency from Er{sup 3+} to Yb{sup 3+}. • Downconversion effect in tellurite glasses. • Downconversion effect observation by thermal lens spectroscopy.

  8. All-optical frequency downconversion technique utilizing a four-wave mixing effect in a single semiconductor optical amplifier for wavelength division multiplexing radio-over-fiber applications.

    Science.gov (United States)

    Kim, Hyoung-Jun; Song, Jong-In

    2012-03-26

    An all-optical frequency downconversion utilizing a four-wave mixing effect in a single semiconductor optical amplifier (SOA) was experimentally demonstrated for wavelength division multiplexing (WDM) radio-over-fiber (RoF) applications. Two WDM optical radio frequency (RF) signals having 155 Mbps differential phase shift keying (DPSK) data at 28.5 GHz were simultaneously down-converted to two WDM optical intermediate frequency (IF) signals having an IF frequency of 4.5 GHz by mixing with an optical local oscillator (LO) signal having a LO frequency of 24 GHz in the SOA. The bit-error-rate (BER) performance of the RoF up-links with different optical fiber lengths employing all-optical frequency downconversion was investigated. The receiver sensitivity of the RoF up-link with a 6 km single mode fiber and an optical IF signal in an optical double-sideband format was approximately -8.5 dBm and the power penalty for simultaneous frequency downconversion was approximately 0.63 dB. The BER performance showed a strong dependence on the fiber length due to the fiber dispersion. The receiver sensitivity of the RoF up-link with the optical IF signal in the optical single-sideband format was reduced to approximately -17.4 dBm and showed negligible dependence on the fiber length.

  9. CASE STUDIES OF CROSS-BORDER CO-OPERATION IN EUROPEAN TOURISM – PERSPECTIVES AND CHALLENGES FOR THE CROSS-BORDER REGION BUCOVINA/OBLAST TSCHERNIWZI

    OpenAIRE

    HEIKE BÄHRE

    2016-01-01

    The article focuses on success factors and management models in destination management for cross-border co-operation in tourism. The method is based on literature research, case-studies in European cross-border-regions and descriptive.

  10. Information transfer to out-of-hours co-operatives: a survey of general practitioners' views in relation to palliative patients.

    LENUS (Irish Health Repository)

    Kiely, Fiona

    2013-12-01

    In Ireland, weekend and night medical cover for community based patients is largely provided by general practice co-operatives. Doctors working in this service do not have direct access to patients\\' medical records which challenges continuity of care.

  11. New Opportunities for Lanthanide Luminescence

    Institute of Scientific and Technical Information of China (English)

    Jean-Claude G. Bünzli; Steve Comby; Anne-Sophie Chauvin; Caroline D. B. Vandevyver

    2007-01-01

    Trivalent lanthanide ions display fascinating optical properties. The discovery of the corresponding elements and their first industrial uses were intimately linked to their optical properties. This relationship has been kept alive until today when many high-technology applications of lanthanide-containing materials such as energy-saving lighting devices, displays, optical fibers and amplifiers, lasers, responsive luminescent stains for biomedical analyses and in cellulo sensing and imaging, heavily rely on the brilliant and pure-color emission of lanthanide ions. In this review we first outlined the basics of lanthanide luminescence with emphasis on f-f transitions, the sensitization mechanisms, and the assessment of the luminescence efficiency of lanthanide-containing emissive molecular edifices. Emphasis was then put on two fast developing aspects of lanthanide luminescence: materials for telecommunications and light emitting diodes, and biomedical imaging and sensing. Recent advances in NIR-emitting materials for plastic amplifiers and waveguides were described, together with the main solutions brought by researchers to minimize non-radiative deactivation of excited states. The demonstration in 1999 that erbium tris(8-hydroxyquinolinate) displayed a bright green emission suitable for organic light emitting diodes (OLEDs) was followed by realizing that in OLEDs, 25% of the excitation energy leads to singlet states and 75% to triplet states. Since lanthanide ions are good triplet quenchers, they now also play a key role in the development of these lighting devices. Luminescence analyses of biological molecules are among the most sensitive analytical techniques known. The long lifetime of the lanthanide excited states allows time-resolved spectroscopy to be used, suppressing the sample autofluorescence and reaching very low detection limits. Not only visible lanthanide sensors are now ubiquitously provided in medical diagnosis and in cell imaging, but the

  12. An analysis of educators' views on their effectiveness to use group work as a co-operative learning strategy / Mary M. Seshabela

    OpenAIRE

    Seshabela, Mary M

    2004-01-01

    The study was undertaken to analyse educator's views on their effectiveness in using group work as a co-operative learning strategy. Specifically the study aims to: To determine through literature the nature of group work as a co-operative learning strategy. To find out views of educators in their effectiveness of using group work as a teaching strategy. The investigation involved 208 educators from middle and secondary schools in Themba District. Close and open ended que...

  13. A new co-operative inversion strategy via fuzzy clustering technique applied to seismic and magnetotelluric data

    Science.gov (United States)

    Thong Kieu, Duy; Kepic, Anton

    2015-04-01

    Geophysical inversion produces very useful images of earth parameters; however, inversion results usually suffer from inherent non-uniqueness: many subsurface models with different structures and parameters can explain the measurements. To reduce the ambiguity, extra information about the earth's structure and physical properties is needed. This prior information can be extracted from geological principles, prior petrophysical information from well logs, and complementary information from other geophysical methods. Any technique used to constrain inversion should be able to integrate the prior information and to guide updating inversion process in terms of the geological model. In this research, we have adopted fuzzy c-means (FCM) clustering technique for this purpose. FCM is a clustering method that allows us to divide the model of physical parameters into a few clusters of representative values that also may relate to geological units based on the similarity of the geophysical properties. This exploits the fact that in many geological environments the earth is comprised of a few distinctive rock units with different physical properties. Therefore FCM can provide a platform to constrain geophysical inversion, and should tend to produce models that are geologically meaningful. FCM was incorporated in both separate and co-operative inversion processing of seismic and magnetotelluric (MT) data with petrophysical constraints. Using petrophysical information through FCM assists the inversion to build a reliable earth model. In this algorithm, FCM plays a role of guider; it uses the prior information to drive the model update process, and also forming an earth model filled with rocks units rather than smooth transitions when the boundary is in doubt. Where petrophysical information from well logs or core measurement is not locally available the cluster petrophysics may be solved for in inversion as well if some knowledge of how many distinctive geological exist. A

  14. 3 July 2007 - Ambassador A. Navarro Llanos, Permanent Representative of the Republic of Bolivia to the United Nations Office and other international organisations in Geneva signing a Co-operation Agreement concerning Scientific and Technical Co-operation in High-Energy Physics with CERN Director General R. Aymar.

    CERN Multimedia

    Maximilien Brice

    2007-01-01

    3 July 2007 - Ambassador A. Navarro Llanos, Permanent Representative of the Republic of Bolivia to the United Nations Office and other international organisations in Geneva signing a Co-operation Agreement concerning Scientific and Technical Co-operation in High-Energy Physics with CERN Director General R. Aymar.

  15. 1 November 2012 - Signature of the Co-operation Agreement between the Administrative Department of Science, Technology and Innovation (COLCIENCIAS) of Colombia and the European Organization for Nuclear Research (CERN) concerning Scientific and Technical Co-operation in High-Energy Physics and related technologies by CERN Director-General R. Heuer, witnessed by Ambassador of Colombia to Switzerland C. Turbay Quintero.

    CERN Multimedia

    Maximilien Brice

    2012-01-01

    1 November 2012 - Signature of the Co-operation Agreement between the Administrative Department of Science, Technology and Innovation (COLCIENCIAS) of Colombia and the European Organization for Nuclear Research (CERN) concerning Scientific and Technical Co-operation in High-Energy Physics and related technologies by CERN Director-General R. Heuer, witnessed by Ambassador of Colombia to Switzerland C. Turbay Quintero.

  16. Co-operation Agreement between the Ministry of Science, Technology and Environment of the Republic of Cuba (CITMA) and CERN concerning The Further Development of Scientific and Technical Co-operation

    CERN Document Server

    2003-01-01

    In the framework of the CERN collaboration with Latin America, co-operation agreements have been established with Argentina, Brazil, Colombia, Chile, Mexico and Peru. They have made possible a growing participation by Latin American particle physicists in the CERN programme, which has important potential for the future. The Cuban particle physics community is highly motivated and relatively advanced, both scientifically and technologically, since many of its members have been trained in installations of the former Soviet Union, many of which now participate in CERN's cooperation with Russia. In addition, Cuba has a good number of experienced computer scientists. A group from the Cuban Institute CEADEN (Centro de Aplicaciones Tecnológicas y Desarollo Nuclear) has recently been accepted unanimously into the ALICE collaboration, with agreed contributions to off-line software and Grid middlewave. Additional Cuban contributions to show controls, data acquisition and testing electronics for the Silicon drift decte...

  17. Luminescent Solar Concentrators – a low cost photovoltaics alternative

    NARCIS (Netherlands)

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

    2013-01-01

    The development and current status of luminescent solar concentrators is reviewed. These solar concentrators generally consist of transparent polymer sheets doped with luminescent species; presently mainly organic dye molecules are used as luminescent species, however semiconductor nanocrystals are

  18. Luminescent Solar Concentrators – a low cost photovoltaics alternative

    NARCIS (Netherlands)

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

    2013-01-01

    The development and current status of luminescent solar concentrators is reviewed. These solar concentrators generally consist of transparent polymer sheets doped with luminescent species; presently mainly organic dye molecules are used as luminescent species, however semiconductor nanocrystals

  19. Investigation into scanning tunnelling luminescence microscopy

    CERN Document Server

    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 provi...

  20. Broadband down-conversion based near infrared quantum cutting in Eu{sup 2+}–Yb{sup 3+} co-doped SrAl{sub 2}O{sub 4} for crystalline silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Tai, Yuping, E-mail: yupingtai@126.com [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry (Ministry of Education), College of Chemistry & Materials Science, Northwest University, Xi’an 710069 (China); Zheng, Guojun, E-mail: zhengguojun88@126.com [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry (Ministry of Education), College of Chemistry & Materials Science, Northwest University, Xi’an 710069 (China); Wang, Hui, E-mail: huiwang@nwu.edu.cn [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry (Ministry of Education), College of Chemistry & Materials Science, Northwest University, Xi’an 710069 (China); National Key Laboratory of Photoelectric Technology and Functional Materials Culture Base, National Photoelectric Technology and Functional Materials & Application of International Science and Technology Cooperation Base, Institute of Photonics & Photon-Technology, Northwest University, Xi' an 710069 (China); Bai, Jintao, E-mail: baijt@nwu.edu.cn [National Key Laboratory of Photoelectric Technology and Functional Materials Culture Base, National Photoelectric Technology and Functional Materials & Application of International Science and Technology Cooperation Base, Institute of Photonics & Photon-Technology, Northwest University, Xi' an 710069 (China)

    2015-03-15

    Near infrared (NIR) quantum cutting involving the down conversion of an absorbed visible photon to emission of two NIR photons was achieved in SrAl{sub 2}O{sub 4}:0.01Eu{sup 2+}, xYb{sup 3+} (x=0, 1, 2, 5, 10, 20, 30 mol%) samples. The photoluminescence properties of samples in visible and NIR regions were measured to verify the energy transfer (ET) from Eu{sup 2+} to Yb{sup 3+}. The results demonstrated that Eu{sup 2+} was an efficient sensitizer for Yb{sup 3+} in the SrAl{sub 2}O{sub 4} host lattice. According to Gaussian fitting analysis and temperature-dependent luminescence experiments, the conclusion was drawn that the cooperative energy transfer (CET) process dominated the ET process and the influence of charge transfer state (CTS) of Yb{sup 3+} could be negligible. As a result, the high energy transfer efficiency (ETE) and quantum yield (QY) have been acquired, the maximum value approached 73.68% and 147.36%, respectively. Therefore, this down-conversion material has potential application in crystalline silicon solar cells to improve conversion efficiency. - Graphical abstract: Near infrared quantum cutting was achieved in Eu{sup 2+}–Yb{sup 3+} co-doped SrAl{sub 2}O{sub 4} samples. The cooperative energy transfer process dominated energy transfer process and high energy transfer efficiency was acquired. - Highlights: • The absorption spectrum of Eu{sup 2+} ion is strong in intensity and broad in bandwidth. • The spectra of Eu{sup 2+} in SrAl{sub 2}O{sub 4} lies in the strongest region of solar spectrum. • The cooperative energy transfer (CET) dominated the energy transfer process. • The domination of CET is confirmed by experimental analysis. • SrAl{sub 2}O{sub 4}:Eu{sup 2+},Yb{sup 3+} show high energy transfer efficiency and long lifetime.

  1. Developments in luminescence measurement techniques

    DEFF Research Database (Denmark)

    Thomsen, Kristina Jørkov; Bøtter-Jensen, L.; Denby, Phil M.

    2006-01-01

    We report on our continuing investigation and development of new measurement facilities for use in irradiation, optical stimulation and luminescence signal detection; these facilities have potential application to all forms of luminescence-based retrospective dosimetry, and are particularly...... intended for use with the Riso TL/OSL reader. We have investigated the potential of new more powerful blue (455 nm) and green (530nm) LEDs, and of gated counting combined with pulsed stimulation light techniques using conventional LEDs. Measurement of time-resolved OSL has resulted in a method of real......; both types are very stable and reproducible. Other recent developments include the modification of a Riso reader to measure both thermally and optically stimulated electrons (TSE and OSE) from granular or chip phosphors. (c) 2006 Elsevier Ltd. All rights reserved....

  2. 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...... retrospective assessment of accident doses received by the population after a nuclear accident. The development of new luminescence techniques after the Chernobyl accident has considerably improved the sensitivity and precision in the evaluation of accident doses. This paper reviews the development work...

  3. 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

  4. Microprocessor, Setx, Xrn2, and Rrp6 co-operate to induce premature termination of transcription by RNAPII.

    Science.gov (United States)

    Wagschal, Alexandre; Rousset, Emilie; Basavarajaiah, Poornima; Contreras, Xavier; Harwig, Alex; Laurent-Chabalier, Sabine; Nakamura, Mirai; Chen, Xin; Zhang, Ke; Meziane, Oussama; Boyer, Frédéric; Parrinello, Hugues; Berkhout, Ben; Terzian, Christophe; Benkirane, Monsef; Kiernan, Rosemary

    2012-09-14

    Transcription elongation is increasingly recognized as an important mechanism of gene regulation. Here, we show that microprocessor controls gene expression in an RNAi-independent manner. Microprocessor orchestrates the recruitment of termination factors Setx and Xrn2, and the 3'-5' exoribonuclease, Rrp6, to initiate RNAPII pausing and premature termination at the HIV-1 promoter through cleavage of the stem-loop RNA, TAR. Rrp6 further processes the cleavage product, which generates a small RNA that is required to mediate potent transcriptional repression and chromatin remodeling at the HIV-1 promoter. Using chromatin immunoprecipitation coupled to high-throughput sequencing (ChIP-seq), we identified cellular gene targets whose transcription is modulated by microprocessor. Our study reveals RNAPII pausing and premature termination mediated by the co-operative activity of ribonucleases, Drosha/Dgcr8, Xrn2, and Rrp6, as a regulatory mechanism of RNAPII-dependent transcription elongation.

  5. The Relationship between journalists and PR practitioners in Romania – Somewhere in between co-operation and conflict

    Directory of Open Access Journals (Sweden)

    Cristina COMAN

    2009-01-01

    Full Text Available One constant idea emerges from all of the studies regarding the relationship between journalists and PR practitioners: this relationship is a complex and ambiguous one. It is quite obvious that both participants aim at holding control over the production and distribution of information; despite this aim, it is certain that none of the two can develop a monopoly over such a process. The inter-dependency between the actors involved in this game is based on the interest in mutual co-operation showed by each of the participants. This very study stands for the fact that by means of the values they referred to, the Romanian journalists and PR professionals express attitudes that are similar to those of their colleagues from other countries where these two professions have a longer tradition behind.

  6. Use of KPIs to Regulate Co-operation and to Improve Intercompany Benchmarking in the Construction Industry

    DEFF Research Database (Denmark)

    Bohnstedt, Kristian Ditlev

    2013-01-01

    With the aim to investigate whether it can fairly be assumed that the prequalification and selection of co-operators via Key Performance Indicators (KPI) provide increased odds in favour of success, a study on contractors consisting of benchmark results from The Benchmark Centre for the Danish...... Construction Sector and financial statements has been accomplished. Through a comparative analysis based on detected correlations between economy and KPIs, it is explained how these factors are linked. The research showed that the use of KPIs has motivated companies to improve their competitive ability, thus...... their ability to become prequalified. It also showed that the use of KPIs (e.g. quality, timeliness, economy, customer satisfaction and accident rates) for selection and prequalification improves the probability of success in the building process as highly rated KPIs have a positive linear relationship...

  7. The ACCEND program: a combined BS and MS program in environmental engineering that includes co-operative work experience.

    Science.gov (United States)

    Bishop, P L; Keener, T C; Kukreti, A R; Kowel, S T

    2004-01-01

    Environmental engineering education has rapidly expanded in recent years and new teaching methods are needed. Many professionals and educators believe that a MS degree in environmental engineering should be the minimum in order to practice the profession, along with practical training. This paper describes an innovative program being offered at the University of Cincinnati that combines an integrated BS in civil engineering and an MS in environmental engineering with extensive practical co-operative education (co-op) experience, all within a five-year period. The program includes distance learning opportunities during the co-op periods. The result is a well-trained graduate who will receive higher pay and more challenging career opportunities, and who will have developed professionalism and maturity beyond that from traditional engineering programs.

  8. Investigation of the Possibilities for Interdisciplinary Co-operation by the Use of Knowledge-based System

    Directory of Open Access Journals (Sweden)

    Ágnes Szeghegyi

    2007-08-01

    Full Text Available Each problem always originates from constraints. The decision is a response tothe challenges by the environment. In order to chose appropriate decision supporttechniques the structural complexity of the problem has to be determined. The aim of theapplication of knowledge based systems is to obtain decision support. In this paper theapplication of the system ‘Doctus’ is illustrated and exemplified in connection withprocessing the problem of the potential co-operation between the industrial companies andinstitutes of higher education. The analysis was carried out by the application of inductiveand deductive inference procedures taking into account the requirements of the companiesand the abilities and skills of the higher educational institutions. The assessment of theresults obtained may generate further dilemmas for the solution of which appropriateknowledge bases can be brought about or the already existing ones have to be refined.

  9. Luminescence properties of a Fibonacci photonic quasicrystal.

    Science.gov (United States)

    Passias, V; Valappil, N V; Shi, Z; Deych, L; Lisyansky, A A; Menon, V M

    2009-04-13

    An active one-dimensional Fibonacci photonic quasi-crystal is realized via spin coating. Luminescence properties of an organic dye embedded in the quasi-crystal are studied experimentally and compared to theoretical simulations. The luminescence occurs via the pseudo-bandedge mode and follows the dispersion properties of the Fibonacci crystal. Time resolved luminescence measurement of the active structure shows faster spontaneous emission rate, indicating the effect of the large photon densities available at the bandedge due to the presence of critically localized states. The experimental results are in good agreement with the theoretical calculations for steady-state luminescence spectra.

  10. Eu2+ luminescence in strontium aluminates

    OpenAIRE

    Dutczak, D.; Juestel, T.; Ronda, C.; Meijerink, A.|info:eu-repo/dai/nl/075044986

    2015-01-01

    The luminescence properties of Eu2+ doped strontium aluminates are reported and reviewed for a variety of aluminates, viz. SrAl12O19, SrAl4O7, Sr4Al14O25, SrAl2O4 and Sr3Al2O6. The aim of the research is to investigate the role of local coordination and covalency of the aluminate host lattice, related to the Sr/Al ratio, on the optical properties of the Eu2+ ion. The UV and VUV excited luminescence spectra as well as luminescence decay curves were recorded to characterize the luminescence pro...

  11. Photon Luminescence of the Moon

    Science.gov (United States)

    Wilson, T.L.; Lee, K.T.

    2009-01-01

    Luminescence is typically described as light emitted by objects at low temperatures, induced by chemical reactions, electrical energy, atomic interactions, or acoustical and mechanical stress. An example is photoluminescence created when photons (electromagnetic radiation) strike a substance and are absorbed, resulting in the emission of a resonant fluorescent or phosphorescent albedo. In planetary science, there exists X-ray fluorescence induced by sunlight absorbed by a regolith a property used to measure some of the chemical composition of the Moon s surface during the Apollo program. However, there exists an equally important phenomenon in planetary science which will be designated here as photon luminescence. It is not conventional photoluminescence because the incoming radiation that strikes the planetary surface is not photons but rather cosmic rays (CRs). Nevertheless, the result is the same: the generation of a photon albedo. In particular, Galactic CRs (GCRs) and solar energetic particles (SEPs) both induce a photon albedo that radiates from the surface of the Moon. Other particle albedos are generated as well, most of which are hazardous (e.g. neutrons). The photon luminescence or albedo of the lunar surface induced by GCRs and SEPs will be derived here, demonstrating that the Moon literally glows in the dark (when there is no sunlight or Earthshine). This extends earlier work on the same subject [1-4]. A side-by-side comparison of these two albedos and related mitigation measures will also be discussed.

  12. Solid-matrix luminescence analysis

    Energy Technology Data Exchange (ETDEWEB)

    Hurtubise, R.J.

    1993-01-15

    Several interactions with lumiphors adsorbed on filter paper were elucidated from experiments with moisture, modulus and heavy-atom salts. The data were interpreted using static and dynamic quenching models, heavy-atom theory, and a theory related to the modulus of paper. With cyclodextrin-salt matrices, it was shown that 10% [alpha]-cyclodextrin/NaCl was very effective for obtaining strong room-temperature fluorescence and moderate room-temperature phosphorescence from adsorbed stereoisomeric tetrols. Extensive photophysical information was obtained for the four tetrols on 10% [alpha]-cyclodextrin/NaCl. The photophysical information acquired was used to develop a method for characterizing two of the tetrols. Work with model compounds adsorbed on deuterated sodium acetate showed that C-H vibrations in the undeuterated sodium acetate were not responsible for the deactivation of the excited triplet state in the model phosphors investigated. A considerable amount of solution luminescence and solid-matrix luminescence data were compared. The most important finding was that in several cases the room-temperature solid-matrix luminescence quantum yields were greater than the solution low-temperature quantum yield values.

  13. dREAM co-operates with insulator-binding proteins and regulates expression at divergently paired genes.

    Science.gov (United States)

    Korenjak, Michael; Kwon, Eunjeong; Morris, Robert T; Anderssen, Endre; Amzallag, Arnaud; Ramaswamy, Sridhar; Dyson, Nicholas J

    2014-08-01

    dREAM complexes represent the predominant form of E2F/RBF repressor complexes in Drosophila. dREAM associates with thousands of sites in the fly genome but its mechanism of action is unknown. To understand the genomic context in which dREAM acts we examined the distribution and localization of Drosophila E2F and dREAM proteins. Here we report a striking and unexpected overlap between dE2F2/dREAM sites and binding sites for the insulator-binding proteins CP190 and Beaf-32. Genetic assays show that these components functionally co-operate and chromatin immunoprecipitation experiments on mutant animals demonstrate that dE2F2 is important for association of CP190 with chromatin. dE2F2/dREAM binding sites are enriched at divergently transcribed genes, and the majority of genes upregulated by dE2F2 depletion represent the repressed half of a differentially expressed, divergently transcribed pair of genes. Analysis of mutant animals confirms that dREAM and CP190 are similarly required for transcriptional integrity at these gene pairs and suggest that dREAM functions in concert with CP190 to establish boundaries between repressed/activated genes. Consistent with the idea that dREAM co-operates with insulator-binding proteins, genomic regions bound by dREAM possess enhancer-blocking activity that depends on multiple dREAM components. These findings suggest that dREAM functions in the organization of transcriptional domains. © The Author(s) 2014. Published by Oxford University Press on behalf of Nucleic Acids Research.

  14. When a business isn’t a business: law and the political in the history of the United Kingdom’s co-operative movement

    Directory of Open Access Journals (Sweden)

    Tara Mulqueen

    2012-05-01

    Full Text Available Contemporary efforts to develop and promote co-operatives and the social economy confront a tension in the competing and often conflicting aims to achieve commercial sustainability in a capitalist market while also promoting social transformation. Through a review of the historical experience of institutionalization in the Co-operative Movement in the United Kingdom, this article attempts to generate insights into these tensions. Despite being seen as unpolitical, co-operatives can be understood as political at the level of re-shaping sociality through co-operative practice. Although the similarity between co-operatives and joint-stock companies produces ambiguities within the movement, this does not in itself detract from the co-operative project. It is argued that the codification of co-operatives in law as bodies corporate constitutes the closure of the political aspect of co-operation and reinforces and gives consequence to the misconception of co-operatives as primarily commercial entities. Los esfuerzos por desarrollar y promover las cooperativas y la economía social se enfrentan a un conflicto entre los objetivos contrapuestos de lograr la sostenibilidad comercial en un mercado capitalista, a la vez que se promueve una transformación de la sociedad. Realizando una revisión de la experiencia histórica de la institucionalización del movimiento cooperativista en el Reino Unido, este artículo pretende analizar estas tensiones. A pesar de ser apolíticas, las cooperativas se pueden entender como un elemento político por su intento de reformular la sociedad. Aunque la similitud entre cooperativas y sociedades anónimas produce ambigüedades dentro del movimiento cooperativista, esto no va, por sí mismo, en detrimento del proyecto de cooperación. Se argumenta que, al contemplar en la legislación a las cooperativas como personas jurídicas, se acaba con el aspecto político de las cooperativas. A su vez, esto refuerza y termina con la

  15. Highly improved upconversion luminescence in NaGd(WO₄)₂:Yb³⁺/Tm³⁺ inverse opal photonic crystals.

    Science.gov (United States)

    Wang, Yunfeng; Xu, Wen; Cui, Shaobo; Xu, Sai; Yin, Ze; Song, Hongwei; Zhou, Pingwei; Liu, Xiaoyan; Xu, Lin; Cui, Haining

    2015-01-28

    The upconversion luminescence (UCL) of rare earth (RE) ions doped nanomaterials has attracted extensive interest because of its wide and great potential applications. However, the lower UCL efficiency is still an obstacle for real applications. Photonic modulation is a novel way to improve the efficiency of UCL. In this work, NaGd(WO4)2:Yb(3+)/Tm(3+) inverse opal photonic crystals (IOPCs) were fabricated through the polymethylmethacrylate (PMMA) template and the modification of the IOPC structure on the emission spectra and dynamics of Tm(3+) ions was systemically studied. It is interesting to observe that in the IOPCs, the high-order UCL (1)D2-(3)H6/(3)F4 was relatively enhanced. At the same time, the local thermal effect induced by laser irradiation was suppressed. Furthermore, the overall intensity ratio of visible UCL to near-infrared (NIR) down-conversion luminescence (DCL) was 2.8-8 times improved than that of the grinded reference (REF) and independent of the photonic stop band (PSB). The studies on UCL dynamics indicated that the nonradiative transition rate of Tm(3+) was considerably suppressed. The facts above indicated that in the IOPCs the UCL efficiency of Tm(3+) was largely improved due to the periodic macroporous structure.

  16. Decision making and co-operation between stakeholders within the process of sick leave. A case study in a Danish municipality

    DEFF Research Database (Denmark)

    Johansen, Kristina; Andersen, John Sahl; Mikkelsen, Sigurd;

    2011-01-01

    The study addresses how recent reforms of the Sickness Benefit Act in Denmark are put into practice. A single case study embedded with five subunits of analysis based on "real life" cases has been conducted in a Danish municipality. Five "sick-listed" citizens and their respective municipal case...... manager and general practitioner (GP) were interviewed. Two key persons within the municipality were interviewed as background informants. The GPs and case managers ability to co-operate was hampered by lack of time, frequent staff turnover, lack of financial resources, and low accessibility....... The motivation for co-operation was low due to low status of social medical issues, lack of feedback and lack of trust. The co-operation was characterized by sequential task integration. The stakeholders encountered difficulties when reciprocal task integration was needed. The decision making was affected...

  17. Luminescence of thermally altered human skeletal remains

    NARCIS (Netherlands)

    Krap, Tristan; Nota, Kevin; Wilk, Leah; van de Goot, Frank; Ruijter, Jan; Duijst, Wilma; Oostra, Roelof Jan

    2017-01-01

    Literature on luminescent properties of thermally altered human remains is scarce and contradictory. Therefore, the luminescence of heated bone was systemically reinvestigated. A heating experiment was conducted on fresh human bone, in two different media, and cremated human remains were recovered

  18. Violet stimulated luminescence: geo- or thermochronometer?

    DEFF Research Database (Denmark)

    Ankjærgaard, Christina; Guralnik, Benny; Porat, N.

    2015-01-01

    The method of quartz optically stimulated luminescence (OSL) dating is widely used, but generally limited to the past ~0.1 million years (Ma) due to early saturation of the desired signal. Violet stimulated luminescence (VSL) of quartz has previously been shown as a promising alternative...

  19. 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

  20. Spectral Characterization of a Novel Luminescent Organogel

    Science.gov (United States)

    Waguespack, Yan; White, Shawn R.

    2007-01-01

    The spectroscopic-based luminescence experiments were designed to expose the students to various concepts of single-triplet excited states, electron spin, vibrational relaxation, fluorescence-phosphorescence lifetimes and quenching. The students were able to learn about luminescence spectra of the gel and have the experience of synthesizing a…

  1. 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

  2. Violet stimulated luminescence: geo- or thermochronometer?

    DEFF Research Database (Denmark)

    Ankjærgaard, Christina; Guralnik, Benny; Porat, N.;

    2015-01-01

    The method of quartz optically stimulated luminescence (OSL) dating is widely used, but generally limited to the past ~0.1 million years (Ma) due to early saturation of the desired signal. Violet stimulated luminescence (VSL) of quartz has previously been shown as a promising alternative...

  3. Time-resolved luminescence from quartz

    NARCIS (Netherlands)

    Chithambo, M.L.; Ankjærgaard, C.; Pagonis, V.

    2016-01-01

    Time-resolved optical stimulation of luminescence has become established as a key method for measurement of optically stimulated luminescence from quartz, feldspar and α-Al2O3:C, all materials of interest in dosimetry. The aim of time-resolved optical stimulation is to separ

  4. 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...

  5. Luminescence of thermally altered human skeletal remains.

    Science.gov (United States)

    Krap, Tristan; Nota, Kevin; Wilk, Leah S; van de Goot, Franklin R W; Ruijter, Jan M; Duijst, Wilma; Oostra, Roelof-Jan

    2017-07-01

    Literature on luminescent properties of thermally altered human remains is scarce and contradictory. Therefore, the luminescence of heated bone was systemically reinvestigated. A heating experiment was conducted on fresh human bone, in two different media, and cremated human remains were recovered from a modern crematory. Luminescence was excited with light sources within the range of 350 to 560 nm. The excitation light was filtered out by using different long pass filters, and the luminescence was analysed by means of a scoring method. The results show that temperature, duration and surrounding medium determine the observed emission intensity and bandwidth. It is concluded that the luminescent characteristic of bone can be useful for identifying thermally altered human remains in a difficult context as well as yield information on the perimortem and postmortem events.

  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

    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...... of these processes is, in general, thermally dependent, and leads either to enhancement or quenching of the luminescence with increasing temperature. Previous studies have measured the combined thermal activation characteristics of all three processes, and show a strong dependence on stimulation energy....... In this article, an initial attempt is made to isolate only the recombination part of the luminescence cycle, and determine its thermal characteristics separately. A Variety of luminescence transitions are examined in a range of both alkali and plagioclase feldspars; three distinct emission types are identified...

  7. Metal plasmon enhanced europium complex luminescence

    Energy Technology Data Exchange (ETDEWEB)

    Liu Feng [Department of Chemistry, Queen' s University, 90 Bader Lane, Kingston, Ontario, K7L 3N6 (Canada); Aldea, Gabriela [Department of Chemistry, Queen' s University, 90 Bader Lane, Kingston, Ontario, K7L 3N6 (Canada); Petru Poni Institute of Macromolecular Chemistry Iasi, Aleea Grigore Ghica Voda 41A, 700487 Iasi (Romania); Nunzi, Jean-Michel, E-mail: nunzijm@queensu.c [Department of Chemistry, Queen' s University, 90 Bader Lane, Kingston, Ontario, K7L 3N6 (Canada)

    2010-01-15

    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){sub 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.

  8. Simulating Single-Photon Sources Based on Backward-Wave Spontaneous Parametric Down-Conversion in a Periodically Poled KTP Waveguide

    Directory of Open Access Journals (Sweden)

    Shukhin A.A.

    2015-01-01

    Full Text Available The properties of the backward-wave spontaneous parametric down-conversion (SPDC in a periodically poled potassium titanyl phosphate (KTP waveguide are studied in the context of creating narrowband heralded sources of single-photon states. The effective index of refraction and spatial profile of different waveguide modes, efficiency of different SPDC processes and purity of heralded photons are calculated numerically for a given waveguide. Compared to the usual co-propagating SPDC, spectral narrowing of the backward-wave SPDC was observed as should be expected. Generation biphoton states in backward-wave regime is experimentally observed in two-photon detection scheme.

  9. Luminescence of carbon nanotube bulbs

    Institute of Scientific and Technical Information of China (English)

    LI ChuanGang; WU DeHai; WANG KunLin; WEI JinQuan; WEI BingQing; ZHU HongWei; WANG ZhiCheng; LUO JianBin; LIU WenJin; ZHENG MingXin

    2007-01-01

    Carbon nanotube (CNT) bulbs made of decimeter-scale double-walled carbon nanotube (DWCNT) strands and films were fabricated and their luminescence properties, including the lighting efficiency, voltage-current relation and thermal stability were investigated. The results show that the DWCNT bulb has a comparable spectrum of visible light with tungsten bulb and its average efficiency is 40% higher than that of a tungsten filament at the same temperature (1400-2300 K). The nanotube filaments show both resistance and thermal stability over a large temperature region. No obvious damage was found for a nanotube bulb illuminating at 2300 K for more than 24 hours in vacuum.

  10. Towards broad range and highly efficient down-conversion of solar spectrum by Er{sup 3+}-Yb{sup 3+} co-doped nano-structured glass-ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez, V.D.; Mendez-Ramos, J. [Departamento de Fisica Fundamental y Experimental, Electronica y Sistemas, Universidad de La Laguna, E-38206 La Laguna, Tenerife (Spain); Tikhomirov, V.K.; Moshchalkov, V.V. [INPAC-Institute for Nanoscale Physics and Chemistry, Katholieke Universiteit Leuven (Belgium); Yanes, A.C. [Departamento de Fisica Basica, Universidad de La Laguna, E-38206 La Laguna, Tenerife (Spain)

    2010-10-15

    The efficiency of semiconductor solar cells could be greatly increased by down-conversion processes, which efficiently split incident solar photons into couples of photons with energy over the bandgap. Here, we show new down-conversion mechanisms in Er{sup 3+}-Yb{sup 3+} co-doped glass-ceramics, where the ions are hosted by fluoride nanoparticles embedded in silica glass. By this means, 350-550 nm photons, absorbed by Er{sup 3+} ions, generate pairs of photons at the range of 650-1550 nm, emitted by Er{sup 3+} and Yb{sup 3+}, with a quantum efficiency approaching the maximum of 200%. (author)

  11. Optical thermometry based on luminescence behavior of Dy{sup 3+}-doped transparent LaF{sub 3} glass ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Bu, Y.Y. [Nanjing University of Posts and Telecommunications, College of Electronic Science and Engineering, Nanjing (China); Nanjing University of Posts and Telecommunications, College of Science, Nanjing (China); Cheng, S.J.; Wang, X.F. [Nanjing University of Posts and Telecommunications, College of Electronic Science and Engineering, Nanjing (China); Key Laboratory of Radio Frequency and Micro-Nano Electronics of Jiangsu Province, Nanjing, Jiangsu (China); Yan, X.H. [Nanjing University of Posts and Telecommunications, College of Electronic Science and Engineering, Nanjing (China); Key Laboratory of Radio Frequency and Micro-Nano Electronics of Jiangsu Province, Nanjing, Jiangsu (China); Nanjing University of Aeronautics and Astronautics, College of Science, Nanjing (China)

    2015-11-15

    Dy{sup 3+}-doped transparent LaF{sub 3} glass ceramics were fabricated, and its structures of resulting glass ceramics are studied by the X-ray diffraction and transmission electron microscopy. Optical temperature sensing of the resulting glass ceramics in the temperature range from 298 to 523 K is studied based on the down-conversion luminescence of Dy{sup 3+} ion. By using fluorescence intensity ratio method, the {sup 4}I{sub 15/2} and {sup 4}F{sub 9/2} of Dy{sup 3+} ions are verified as thermally coupled levels. A minimum S{sub R} = 1.16 x 10{sup -4} K{sup -1} is obtained at T = 294 K. By doping Eu{sup 3+} ion, the overall emission color of Eu{sup 3+}-Dy{sup 3+} co-doped transparent glass ceramics can be tuned from white to yellow with the temperature increase through energy transfer between Eu{sup 3+} and Dy{sup 3+}. Additionally, the thermal stability of the Dy{sup 3+} single-doped transparent glass ceramics becomes higher after doping Eu{sup 3+} ion. (orig.)

  12. Zika virus evades interferon-mediated antiviral response through the co-operation of multiple nonstructural proteins in vitro

    Science.gov (United States)

    Wu, Yaoxing; Liu, Qingxiang; Zhou, Jie; Xie, Weihong; Chen, Cheng; Wang, Zefang; Yang, Haitao; Cui, Jun

    2017-01-01

    Type I interferon (IFN) serves as the first line of defense against invading pathogens. Inhibition of IFN-triggered signaling cascade by Zika virus (ZIKV) plays a critical role for ZIKV to evade antiviral responses from host cells. Here we demonstrate that ZIKV nonstructural proteins NS1, NS4B and NS2B3 inhibit the induction of IFN and downstream IFN-stimulated genes through diverse strategies. NS1 and NS4B of ZIKV inhibit IFNβ signaling at TANK-binding kinase 1 level, whereas NS2B-NS3 of ZIKV impairs JAK–STAT signaling pathway by degrading Jak1 and reduces virus-induced apoptotic cell death. Furthermore, co-operation of NS1, NS4B and NS2B3 further enhances viral infection by blocking IFN-induced autophagic degradation of NS2B3. Hence, our study reveals a novel antagonistic system employing multiple ZIKV nonstructural proteins in restricting the innate antiviral responses. PMID:28373913

  13. Co-operative mineralization and protein self-assembly in amelogenesis: silica mineralization and assembly of recombinant amelogenins in vitro.

    Science.gov (United States)

    Fowler, Christabel E; Beniash, Elia; Yamakoshi, Yasuo; Simmer, James P; Margolis, Henry C

    2006-05-01

    An amorphous silica mineralization technique was used to produce inorganic/protein composites to elucidate the structure and mechanism of formation of amelogenin assemblies, which may play an important role in regulating enamel structure during the initial stages of amelogenesis. Full-length recombinant amelogenins from mouse (rM179) and pig (rP172) were investigated along with key degradation products (rM166 and native P148) lacking the hydrophilic C terminus found in parent molecules. The resulting products were examined using transmission electron microscopy and/or small-angle X-ray scattering. Using protein concentrations of 0.1-3 mg ml-1, large monodisperse spheres of remarkably similar mean diameters were observed using rM179 (124+/-4 nm) and rP172 (126+/-7 nm). These spheres also exhibited 'internal structure', comprising nearly spherical monodisperse particles of approximately 20 nm in diameter. In the presence of rM166, P148, and bovine serum albumin (control), large unstructured and randomly shaped particles (250-1000 nm) were observed. Without added protein, large dense spherical particles of silica (mean approximately 500 nm) lacking internal structure were produced. These findings demonstrate that full-length amelogenins have the ability to form higher-order structures, whereas amelogenins that lack the hydrophilic C terminus do not. The results also suggest that full-length amelogenin can guide the formation of organized mineralized structures through co-operative interactions between assembling protein and forming mineral.

  14. Sympathetic control of skeletal muscle function: possible co-operation between noradrenaline and neuropeptide Y in rabbit jaw muscles.

    Science.gov (United States)

    Grassi, C; Deriu, F; Roatta, S; Santarelli, R; Azzena, G B; Passatore, M

    1996-07-19

    Stimulation of the cervical sympathetic nerve at 10/s increases by 12.9 +/- 0.7% peak tension of maximal twitches in the directly stimulated jaw muscles and markedly depresses (41.6 +/- 1.3%) the tonic vibration reflex (TVR) elicited in the same muscles by vibration of the mandible. Both effects are not significantly influenced by administration of beta-adrenoceptor antagonists. When both alpha- and beta-adrenergic receptors are blocked, sympathetic stimulation induces a very small increase in twitch tension (3.8 +/- 0.7%), while no detectable change in the TVR is observed. Close arterial injection of alpha 1-adrenoceptor agonist phenylephrine mimics the effects induced by sympathetic stimulation on twitch tension and TVR, dose-dependently. The noradrenaline co-transmitter neuropeptide Y also produces a long-lasting, dose-dependent increase in the twitch tension which is unaffected by blockade of adrenergic receptors as well as of the neuromuscular junctions. Contribution of neuropeptide Y to the sympathetically-induced reduction of the stretch reflex is not clearly demonstrated. These data suggest that co-operation between noradrenaline and neuropeptide Y may be effective in determining sympathetic modulation of skeletal muscle function.

  15. A Cytotoxic, Co-operative Interaction Between Energy Deprivation and Glutamate Release From System xc− Mediates Aglycemic Neuronal Cell Death

    Directory of Open Access Journals (Sweden)

    Trista L. Thorn

    2015-11-01

    Full Text Available The astrocyte cystine/glutamate antiporter (system xc− contributes substantially to the excitotoxic neuronal cell death facilitated by glucose deprivation. The purpose of this study was to determine the mechanism by which this occurred. Using pure astrocyte cultures, as well as, mixed cortical cell cultures containing both neurons and astrocytes, we found that neither an enhancement in system xc− expression nor activity underlies the excitotoxic effects of aglycemia. In addition, using three separate bioassays, we demonstrate no change in the ability of glucose-deprived astrocytes—either cultured alone or with neurons—to remove glutamate from the extracellular space. Instead, we demonstrate that glucose-deprived cultures are 2 to 3 times more sensitive to the killing effects of glutamate or N-methyl-D-aspartate when compared with their glucose-containing controls. Hence, our results are consistent with the weak excitotoxic hypothesis such that a bioenergetic deficiency, which is measureable in our mixed but not astrocyte cultures, allows normally innocuous concentrations of glutamate to become excitotoxic. Adding to the burgeoning literature detailing the contribution of astrocytes to neuronal injury, we conclude that under our experimental paradigm, a cytotoxic, co-operative interaction between energy deprivation and glutamate release from astrocyte system xc− mediates aglycemic neuronal cell death.

  16. Effect of Oral Midazolam Premedication on Children’s Co-operation Before General Anesthesia in Pediatric Dentistry

    Science.gov (United States)

    Kaviani, Nasser; Shahtusi, Mina; Haj Norousali Tehrani, Maryam; Nazari, Sara

    2014-01-01

    Statement of the Problem: Premedication is expedient in reducing the psychological trauma from recalling the unpleasant pre-anesthetic phases, hence, inducing a trouble-free anesthesia. Purpose: This study aimed to determine the effectiveness of oral midazolam in co-operation of the subjects before general anesthesia and in recalling the pre-anesthetic phases, performed on children candidate for dental treatment under general anesthesia. Materials and Method: In this prospective clinical trial study, 62 healthy non-cooperative children, candidate for dental treatment under general anesthesia, were randomly divided into study and control groups. The children received 20ml orange juice, 20 minutes before starting the anesthesia. The juice of the test group contained 0.5mg/kg of midazolam and that of the control group included no medication. The induction and the maintenance process of anesthesia were similar in both groups. The manner of subjects when separated from parents, their cooperation during intravenous catheterization, and recalling the pre-anesthetic events were recorded. Data were analyzed by adopting chi-square and Mann-Whitney tests. Results: Most of the children in the test group had a comfortable separation from parents, restful IV catheterization and 90% of the subjects did not recall the pre-anesthetic events. Conclusion: Under the circumstances of this study, it could be concluded that 0.5mg/kg oral midazolam premedication is effective for comfortable separation of children from parents and restful IV catheterization and also forgetting the pre-anesthetic events. PMID:25191661

  17. A Cytotoxic, Co-operative Interaction Between Energy Deprivation and Glutamate Release From System xc- Mediates Aglycemic Neuronal Cell Death.

    Science.gov (United States)

    Thorn, Trista L; He, Yan; Jackman, Nicole A; Lobner, Doug; Hewett, James A; Hewett, Sandra J

    2015-01-01

    The astrocyte cystine/glutamate antiporter (system xc(-)) contributes substantially to the excitotoxic neuronal cell death facilitated by glucose deprivation. The purpose of this study was to determine the mechanism by which this occurred. Using pure astrocyte cultures, as well as, mixed cortical cell cultures containing both neurons and astrocytes, we found that neither an enhancement in system xc(-) expression nor activity underlies the excitotoxic effects of aglycemia. In addition, using three separate bioassays, we demonstrate no change in the ability of glucose-deprived astrocytes--either cultured alone or with neurons--to remove glutamate from the extracellular space. Instead, we demonstrate that glucose-deprived cultures are 2 to 3 times more sensitive to the killing effects of glutamate or N-methyl-D-aspartate when compared with their glucose-containing controls. Hence, our results are consistent with the weak excitotoxic hypothesis such that a bioenergetic deficiency, which is measureable in our mixed but not astrocyte cultures, allows normally innocuous concentrations of glutamate to become excitotoxic. Adding to the burgeoning literature detailing the contribution of astrocytes to neuronal injury, we conclude that under our experimental paradigm, a cytotoxic, co-operative interaction between energy deprivation and glutamate release from astrocyte system xc(-) mediates aglycemic neuronal cell death.

  18. Functional silk: colored and luminescent.

    Science.gov (United States)

    Tansil, Natalia C; Koh, Leng Duei; Han, Ming-Yong

    2012-03-15

    Silkworm silk is among the most widely used natural fibers for textile and biomedical applications due to its extraordinary mechanical properties and superior biocompatibility. A number of physical and chemical processes have also been developed to reconstruct silk into various forms or to artificially produce silk-like materials. In addition to the direct use and the delicate replication of silk's natural structure and properties, there is a growing interest to introduce more new functionalities into silk while maintaining its advantageous intrinsic properties. In this review we assess various methods and their merits to produce functional silk, specifically those with color and luminescence, through post-processing steps as well as biological approaches. There is a highlight on intrinsically colored and luminescent silk produced directly from silkworms for a wide range of applications, and a discussion on the suitable molecular properties for being incorporated effectively into silk while it is being produced in the silk gland. With these understanding, a new generation of silk containing various functional materials (e.g., drugs, antibiotics and stimuli-sensitive dyes) would be produced for novel applications such as cancer therapy with controlled release feature, wound dressing with monitoring/sensing feature, tissue engineering scaffolds with antibacterial, anticoagulant or anti-inflammatory feature, and many others.

  19. Solid-surface luminescence analysis

    Energy Technology Data Exchange (ETDEWEB)

    Hurtubise, R.J.

    1991-01-01

    We have characterized several interactions that are very important in solid-matrix luminescence. With silica gel chromatoplates and filter paper, simple equations were derived for calculating the individual contributions to the percent decrease in luminescence due to either moisture or to a quenching gas. For sodium acetate as a solid matrix and p-aminobenzoate as a model compound, it was concluded that p-aminobenzoate was incorporated into the crystal structure of sodium acetate, and the triplet energy was lost be skeletal vibrations in sodium acetate. Also, with the same system is was shown that p-aminobenzoate did not undergo rotational relaxation, and thus rotational processes did not contribute to the deactivation of the triplet state. Several results were obtained from model compounds adsorbed on filter paper under different temperature and humidity conditions and with a variety of heavy atoms present. Fundamental photophysical equations were used in calculating several basic parameters that revealed information on rate processes and how the absorbed energy was distributed in an adsorbed lumiphor. The most important advancement with filter paper was the development of equations that relate phosphorescence parameters of adsorbed phosphors to the Young's modulus of filter paper. These equations are based on a fundamental theory that relates the hydrogen-bonding network of paper to the modulus of paper.

  20. Upconversion luminescence in Yb 3+-doped yttrium aluminum garnets

    Science.gov (United States)

    Xu, Xiaodong; Zhao, Zhiwei; Song, Pingxin; Jiang, Benxue; Zhou, Guoqing; Xu, Jun; Deng, Peizhen; Bourdet, Gilbert; Christophe Chanteloup, Jean; Zou, Ji-Ping; Fulop, Annabelle

    2005-03-01

    In this paper, we present results on upconversion luminescence performed on Yb 3+-doped yttrium aluminum garnets under 940 nm excitation. The upconversion luminescence was ascribed to Yb 3+ cooperative luminescence and the presence of rare earth impurity ions. The cooperative luminescence spectra as a function of Yb concentration were measured and the emission intensity variation with Yb concentration was discussed. Yb 3+ energy migration quenched the cooperative luminescence of Yb:YAG crystals with doping level over 15 at%.

  1. Advanced research workshop "South Caucasus : making the best use of external assistance for stability building and for co-operation with NATO"

    Index Scriptorium Estoniae

    2003-01-01

    Leedu Kaitseministeeriumi poolt 22.-23. septembrini 2003 Vilniuses korraldatud seminaril "South Caucasus: making the best use of external assistance for stability building and for co-operation with NATO" arutati, kas ja kuidas on Lõuna-Kaukaasia regioonis võimalik rakendada Balti riikide julgeolekualase koostöö kogemusi

  2. Advanced research workshop "South Caucasus : making the best use of external assistance for stability building and for co-operation with NATO"

    Index Scriptorium Estoniae

    2003-01-01

    Leedu Kaitseministeeriumi poolt 22.-23. septembrini 2003 Vilniuses korraldatud seminaril "South Caucasus: making the best use of external assistance for stability building and for co-operation with NATO" arutati, kas ja kuidas on Lõuna-Kaukaasia regioonis võimalik rakendada Balti riikide julgeolekualase koostöö kogemusi

  3. Managing the Co-operation-Competition Dilemma in R&D Alliances : A Multiple Case Study in the Advanced Materials Industry

    NARCIS (Netherlands)

    Faems, Dries; Janssens, Maddy; Van Looy, Bart

    2010-01-01

    Generating value in R&D alliances requires intensive and fine-grained interaction between collaborating partners. At the same time, more intensive co-operation increases the risk of competitive abuse of the R&D alliance by one or more partners. In this study, we explore how managers address the fund

  4. Luminescence Properties of a Fibonacci Photonic Quasicrystal

    CERN Document Server

    Passias, Vasilios; Shi, Zhou; Deych, Lev; Lisyansky, Alexander; Menon, Vinod M

    2008-01-01

    We report the realization of an active one-dimensional Fibonacci photonic quasi-crystal via spin coating. Manipulation of the luminescence properties of an organic dye embedded in the quasi-crystal is presented and compared to theoretical simulations. The luminescence occurs via the pseudo-bandedge mode and follows the dispersion properties of the Fibonacci crystal. Time resolved luminescence measurement of the active structure shows faster spontaneous emission rate, indicating the effect of the large photon densities available at the bandedge due to the presence of critically localized states. The experimental results are in excellent agreement with the theoretical calculations.

  5. Laser-induced down-conversion and infrared phosphorescence emissivity of novel ligand-free perovskite nanomaterials

    Science.gov (United States)

    Ahmed, M. A.; Khafagy, Rasha M.; El-sayed, O.

    2014-03-01

    For the first time, standalone and ligand-free series of novel rare-earth-based perovskite nanomaterials are used as near infrared (NIR) and mid infrared (MIR) emitters. Nano-sized La0.7Sr0.3M0.1Fe0.9O3; where M = 0, Mn2+, Co2+ or Ni2+ were synthesized using the flash auto-combustion method and characterized using FTIR, FT-Raman, SEM and EDX. Photoluminescence spectra were spontaneously recorded during pumping the samples with 0.5 mW of green laser emitting continuously at 532 nm. La0.7Sr0.3FeO3 (where M = 0) did not result in any infrared emissivity, while intense near and mid infrared down-converted phosphorescence was released from the M-doped samples. The released phosphorescence greatly shifted among the infrared spectral region with changing the doping cation. Ni2+-doped perovskite emitted at the short-wavelength near-infrared region, while Mn2+ and Co2+-doped perovskites emitted at the mid-wavelength infrared region. The detected laser-induced spontaneous parametric down-conversion phosphorescence (SPDC) occurred through a two-photon process by emitting two NIR or MIR photons among a cooperative energy transfer between the La3+ cations and the M2+ cations. Combining SrFeO3 ceramic with both a rare earth cation (RE3+) and a transition metal cation (Mn2+, Co2+ or Ni2+), rather than introducing merely RE3+ cations, greatly improved and controlled the infrared emissivity properties of synthesized perovskites through destroying their crystal symmetry and giving rise to asymmetrical lattice vibration and the nonlinear optical character. The existence of SPDC in the M2+-doped samples verifies their nonlinear character after the absence of this character in La0.7Sr0.3FeO3. Obtained results verify that, for the first time, perovskite nanomaterials are considered as nonlinear optical crystals with intense infrared emissivity at low pumping power of visible wavelengths, which nominates them for photonic applications and requires further studies regarding their lasing

  6. Japan-Australia Co-operative Program on research and development of technology for the management of high level radioactive wastes: phase II (1990-1995)

    Energy Technology Data Exchange (ETDEWEB)

    Banba, Tsunetaka [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Hart, K.P. [eds.

    1996-05-01

    The major activities associated with Japan-Australia Co-operative Program were the preparation, characterization and subsequent testing of both Cm-doped Synroc containing PW-4b simulated waste and Cm-doped single-phase zirconolite and perovskite, and the initiation of studies on naturally-occurring zirconolites to study the long-term durability of this mineral phase over geological time. The preparation of the Cm-doped samples was carried out in JAERI`s WASTEF facility at Tokai, with technical information and assistance provided by ANSTO where necessary. The experiments were designed to induce accelerated radiation damage in Synroc samples that would correspond to periods of Synroc storage of up to 100,000 years. The results are of considerable importance in evaluating the potential of the Synroc process as a means of dealing with HLW waste streams and represent a significant contribution to the understanding of the ability of Synroc to immobilize HLW elements. Overall the Phase II Co-operative Program has continued the excellent co-operative working relationship between the staff at the two institutions, and provided a better understanding of the potential advantages and limitations of Synroc as a second generation waste form. The work has shown the need for additional studies to be carried out on the effect of the levels of Cm-doping on the Cm leach rate, extension of natural analogue studies to define the geological conditions under which zirconolite is stable and development of models to provide long-term predictions of releases of HLW elements from Synroc under a range of repository conditions. It is strongly recommended that the program carried out in Phase II of the Co-operative Agreement be extended for a further three years to allow additional information on the above areas to be collected and reported in a document providing an overview of the Co-operative Program and recommendations on HLW management strategies. (J.P.N.).

  7. Directed evolution of Tau class glutathione transferases reveals a site that regulates catalytic efficiency and masks co-operativity.

    Science.gov (United States)

    Axarli, Irine; Muleta, Abdi W; Vlachakis, Dimitrios; Kossida, Sophia; Kotzia, Georgia; Maltezos, Anastasios; Dhavala, Prathusha; Papageorgiou, Anastassios C; Labrou, Nikolaos E

    2016-03-01

    A library of Tau class GSTs (glutathione transferases) was constructed by DNA shuffling using the DNA encoding the Glycine max GSTs GmGSTU2-2, GmGSTU4-4 and GmGSTU10-10. The parental GSTs are >88% identical at the sequence level; however, their specificity varies towards different substrates. The DNA library contained chimaeric structures of alternated segments of the parental sequences and point mutations. Chimaeric GST sequences were expressed in Escherichia coli and their enzymatic activities towards CDNB (1-chloro-2,4-dinitrobenzene) and the herbicide fluorodifen (4-nitrophenyl α,α,α-trifluoro-2-nitro-p-tolyl ether) were determined. A chimaeric clone (Sh14) with enhanced CDNB- and fluorodifen-detoxifying activities, and unusual co-operative kinetics towards CDNB and fluorodifen, but not towards GSH, was identified. The structure of Sh14 was determined at 1.75 Å (1 Å=0.1 nm) resolution in complex with S-(p-nitrobenzyl)-glutathione. Analysis of the Sh14 structure showed that a W114C point mutation is responsible for the altered kinetic properties. This was confirmed by the kinetic properties of the Sh14 C114W mutant. It is suggested that the replacement of the bulky tryptophan residue by a smaller amino acid (cysteine) results in conformational changes of the active-site cavity, leading to enhanced catalytic activity of Sh14. Moreover, the structural changes allow the strengthening of the two salt bridges between Glu(66) and Lys(104) at the dimer interface that triggers an allosteric effect and the communication between the hydrophobic sites.

  8. Amino acid catalyzed bulk-phase gelation of organoalkoxysilanes via a transient co-operative self-assembly.

    Science.gov (United States)

    Shen, Shukun; Hu, Daodao; Sun, Peipei; Zhang, Xiaoru; Parikh, Atul N

    2009-10-15

    We report acceleration in the rate of bulk phase gelation of an organoalkoxysilane, 3-methacryloxypropyltrimethoxysilane (MAPTMS), in the presence of an amphiphilic additive, N-phenyl glycine (NPG). The MAPTMS gelation occurs within 30 min in the presence of 0.5 wt % NPG, which took several months in the absence of NPG. Using a combination of ATR-FT IR, (29)Si NMR, (1)H NMR, viscosity analysis, SEM, UV-vis, and pi-A isotherm measurements, we elucidate the molecular-level details of the structural changes during NPG-catalyzed MPTMS gelation rate. On the basis of these results, we propose a gelation mechanism in which a transient cooperative self-assembly process fosters hydrolysis and retards early condensation thereby promoting the formation of extended three-dimensionally cross-linked gels. Specifically, the amphiphilic character of the hydrolysis product of MAPTMS, consisting of a hydrophobic tail R = -CH(2)CH(2)CH(2)O(CO)C(CH(3)) horizontal lineCH(2) and a hydrophilic Si-OH headgroup, promotes micelle formation at high MAPTMS/water ratio. NPG readily inserts within these micelles thus retarding the topotactic condensation of silanols at the micellar surface. This in turn allows for a more complete hydrolysis of Si-OCH(3) groups prior to condensation in MAPTMS. With increased silanol concentration at the micellar periphery, a delayed condensation phase initiates. This formation of a covalently bonded Si-O-Si framework (and possibly also the formation of the methanol byproduct) likely destabilizes the micellar motif thus promoting its transformation into condensed mesophases (e.g., lamellar microstructure) upon gelation. Because of the generality of this transient and co-operative organic-inorganic self-assembly between hydrolyzed amphiphilic organoalkoxysilanes and surfactant-like amino acid additives, we envisage applications in controlling bulk phase gelation of many chain-substituted organoalkoxysilanes.

  9. How to create more supportive supervision for primary healthcare: lessons from Ngamiland district of Botswana: co-operative inquiry group

    Directory of Open Access Journals (Sweden)

    Oathokwa Nkomazana

    2016-06-01

    Full Text Available Background: Supportive supervision is a way to foster performance, productivity, motivation, and retention of health workforce. Nevertheless there is a dearth of evidence of the impact and acceptability of supportive supervision in low- and middle-income countries. This article describes a participatory process of transforming the supervisory practice of district health managers to create a supportive environment for primary healthcare workers. Objective: The objective of the study was to explore how district health managers can change their practice to create a more supportive environment for primary healthcare providers. Design: A facilitated co-operative inquiry group (CIG was formed with Ngamiland health district managers. CIG belongs to the participatory action research paradigm and is characterised by a cyclic process of observation, reflection, planning, and action. The CIG went through three cycles between March 2013 and March 2014. Results: Twelve district health managers participated in the inquiry group. The major insights and learning that emerged from the inquiry process included inadequate supervisory practice, perceptions of healthcare workers’ experiences, change in the managers’ supervision paradigm, recognition of the supervisors’ inadequate supervisory skills, and barriers to supportive supervision. Finally, the group developed a 10-point consensus on what they had learnt regarding supportive supervision. Conclusion: Ngamiland health district managers have come to appreciate the value of supportive supervision and changed their management style to be more supportive of their subordinates. They also developed a consensus on supportive supervision that could be adapted for use nationally. Supportive supervision should be prioritised at all levels of the health system, and it should be adequately resourced.

  10. Effect of Oral Midazolam Premedication on Children’s Co-operation Before General Anesthesia in Pediatric Dentistry

    Directory of Open Access Journals (Sweden)

    Nasser Kaviani

    2014-09-01

    Full Text Available Statement of the Problem: Premedication is expedient in reducing the psychological trauma from recalling the unpleasant pre-anesthetic phases, hence, inducing a trouble-free anesthesia. Purpose: This study aimed to determine the effectiveness of oral midazolam in co-operation of the subjects before general anesthesia and in recalling the pre-anesthetic phases, performed on children candidate for dental treatment under general anesthesia. Materials and Method: In this prospective clinical trial study, 62 healthy non-cooperative children, candidate for dental treatment under general anesthesia, were randomly divided into study and control groups. The children received 20ml orange juice, 20 minutes before starting the anesthesia. The juice of the test group contained 0.5mg/kg of midazolam and that of the control group included no medication. The induction and the maintenance process of anesthesia were similar in both groups. The manner of subjects when separated from parents, their cooperation during intravenous catheterization, and recalling the pre-anesthetic events were recorded. Data were analyzed by adopting chi-square and Mann-Whitney tests. Results: Most of the children in the test group had a comfortable separation from parents, restful IV catheterization and 90% of the subjects did not recall the pre-anesthetic events. Conclusion: Under the circumstances of this study, it could be concluded that 0.5mg/kg oral midazolam premedication is effective for comfortable separation of children from parents and restful IV catheterization and also forgetting the pre-anesthetic events.

  11. Nanocrystals for luminescent solar concentrators.

    Science.gov (United States)

    Bradshaw, Liam R; Knowles, Kathryn E; McDowall, Stephen; Gamelin, Daniel R

    2015-02-11

    Luminescent solar concentrators (LSCs) harvest sunlight over large areas and concentrate this energy onto photovoltaics or for other uses by transporting photons through macroscopic waveguides. Although attractive for lowering solar energy costs, LSCs remain severely limited by luminophore reabsorption losses. Here, we report a quantitative comparison of four types of nanocrystal (NC) phosphors recently proposed to minimize reabsorption in large-scale LSCs: two nanocrystal heterostructures and two doped nanocrystals. Experimental and numerical analyses both show that even the small core absorption of the leading NC heterostructures causes major reabsorption losses at relatively short transport lengths. Doped NCs outperform the heterostructures substantially in this critical property. A new LSC phosphor is introduced, nanocrystalline Cd(1-x)Cu(x)Se, that outperforms all other leading NCs by a significant margin in both small- and large-scale LSCs under full-spectrum conditions.

  12. Luminescent Lariat Aza-Crown Ether

    Directory of Open Access Journals (Sweden)

    Burkhard König

    2010-03-01

    Full Text Available Lariat ethers are interesting recognition motifs in supramolecular chemistry. The synthesis of a luminescent lariat ether with triglycol chain by azide–alkyne (Huisgen cycloaddition is presented.

  13. 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.

  14. 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...... of rock surfaces is successfully tested by application to two different quartz-rich rock types (sandstone and quartzite). Together with the measurement of infrared stimulated luminescence (IRSL) signals as a function of depth into the surface of different granites it is clear that both OSL and IRSL can....... Based on the studies of residual luminescence as a function of depth into a rock surface discussed above, a model is developed that relates this increase in residual luminescence to the exposure time. The model is then further developed using the quartz OSL signal from buried quartzite cobbles...

  15. 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...... retrospective assessment of accident doses received by the population after a nuclear accident. The development of new luminescence techniques after the Chernobyl accident has considerably improved the sensitivity and precision in the evaluation of accident doses. This paper reviews the development work......, especially on optically stimulated luminescence methods for retrospective assessment of accident doses carried out at Riso National Laboratory in collaboration with the University of Helsinki as part bf a joint European Union research project. We demonstrate that doses lower than 100 mGy can be measured from...

  16. Orbital surveys of solar stimulated luminescence

    Science.gov (United States)

    Hemphill, W. R.; Theisen, A. F.; Tyson, R. M.; Granata, J. S.

    The Fraunhofer line discriminator (FLD) is an electro-optical device for imaging natural and manmade materials which have been stimulated to luminesce by the sun. An airborne FLD has been used to detect geochemically stressed vegetation, drought-stressed agricultural crops, industrial and residential pollution effluents, marine oil seeps, phosphate rock, uranium-bearing sandstone, and bioluminescent ocean plankton. Three-dimensional perspective plots of excitation and emission spectra, measured with a laboratory spectrometer, graphically depict similarities and differences in luminescence properties between sample materials. The laboratory data also include luminescence intensities at six Fraunhofer lines in the visible and near-infrared regions of the electromagnetic spectrum. Both the airborne and laboratory data suggest the feasibility of delineating and monitoring at least some of these luminescing materials from orbital altitude, such as a test flight aboard the Space Shuttle using an improved third-generation FLD.

  17. 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...

  18. 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

  19. 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)

  20. Co-operative agreements and the EU Water Framework Directive in conjunction with the Common Agricultural Policy

    Science.gov (United States)

    Heinz, I.

    2008-05-01

    This paper discusses the significance of voluntary arrangements for the water and agricultural policies in the European Union. The current implementation of the European Water Framework Directive (WFD) and the reform of the Common Agricultural Policy (CAP) require new approaches in water management. As many case studies have shown, co-operative agreements (CAs) between water companies, farmers and authorities can help to reduce environmental pressures on water bodies. The main reasons for that are: i) water companies are ready to advise and financially support farmers in changing production methods; ii) changes of farming practices are tailored to the site-specific requirements; iii) farmers and water companies are interested in minimising the costs and environmental pressures as they benefit, for example, from modernization of farming methods, and reductions in cost of water treatment, and iv) voluntarily agreed commitments to change farming practices are often stricter than statutory rules. Moreover, precautionary rather than remedial measures are preferred. Tackling diffuse pollution is one of the main concerns of the WFD. CAs can enhance the cost-effectiveness of actions within the programmes of measures so that good water status is achieved by 2015. In CAs all relevant stakeholders, located in catchment areas of agricultural usage, can be involved. Thus, they can help to foster integrated water resources management. In particular, disproportionate costs of changing farming practices can be identified. With regard to the recent CAP reform, financial support for farmers will be linked to compliance with environmental standards and further commitments. This concerns both direct payments and agri-environmental programmes. The experience gained in CAs can provide information on best agricultural practices. Informed farmers are more ready to meet environmental requirements. Because CAs implement the most cost-effective changes in farming practice, it can be assumed

  1. Co-operative agreements and the EU Water Framework Directive in conjunction with the Common Agricultural Policy

    Directory of Open Access Journals (Sweden)

    I. Heinz

    2007-06-01

    Full Text Available This paper discusses the significance of voluntary arrangements for the water and agricultural policies in the European Union. The current implementation of the European Water Framework Directive (WFD and the reform of the Common Agricultural Policy (CAP require new approaches in water management. As many case studies have shown, co-operative agreements (CAs between water companies, farmers and authorities can help to reduce environmental pressures on water bodies. The main reasons for that are: i water companies are ready to advise and financially support farmers in changing production methods; ii changes of farming practices are tailored to the site-specific requirements; iii farmers and water companies are interested in minimising the costs and environmental pressures as they benefit, for example, from modernization of farming methods, and reductions in cost of water treatment, and iv voluntarily agreed commitments to change farming practices are often stricter than statutory rules. Moreover, precautionary rather than remedial measures are preferred. Tackling diffuse pollution is one of the main concerns of the WFD. CAs can enhance the cost-effectiveness of actions within the programmes of measures so that good water status is achieved by 2015. In CAs all relevant stakeholders, located in catchment areas of agricultural usage, can be involved. Thus, they can help to foster integrated water resources management. In particular, disproportionate costs of changing farming practices can be identified. With regard to the recent CAP reform, financial support for farmers will be linked to compliance with environmental standards and further commitments. This concerns both direct payments and agri-environmental programmes. The experience gained in CAs can provide information on best agricultural practices. Informed farmers are more ready to meet environmental requirements. Because CAs implement the most cost-effective changes in farming practice, it

  2. Gendered experiences of conflict and co-operation in heterosexual relations of Somalis in exile in Gothenburg, Sweden.

    Science.gov (United States)

    Aden, A S; Dahlgren, L; Tarsitani, G

    2004-01-01

    Political upheaval and poverty at home has been forcing many Somalis to immigrate. These immigrants do not only leave their physical house, families, relatives, loved ones, friends, but also familiarities, culture, customs, and often they do end up in no man's land being between their own and new home culture. Available reports suggest that there are about 15,000 Somalis in Sweden and their majority came here from late 1989 to 1996. About one third these immigrants live in and around the city of Gothenburg. This paper explores and describes gendered experiences of conflict and co-operation in heterosexual relations of Somalis in exile in Gothenburg, Sweden. A qualitative sociological in-depth interviews with 6 women and 7 men was performed during May 1999 to January 2000. A follow up focus group interviews with 10 people (2 women and 8 men) was also carried on. The results show that both the Somali culture and Muslim religion do not support the children being taught sex education in schools or the names of the sex organs being pronounced other than to be used as metaphors. The girls, unlike their age group males, experience a very painful and terrifying process during childhood in which their self-esteem is downgraded by means of serious degrading traditional active violence such as female genital mutilation and visible virginity control. The narratives tell stories in which Somali women are degraded and expected to obey in situations characterised by their man's arbitrariness. They are subject to a very extensive form of social control, which is especially pronounced on issues regarding sexuality. Their integrity as women is, consequently set aside. When Somali refugees came to Sweden some of them came to adopt much of the modern lifestyle and cultural norm systems, preferable young people and some of the females. Relating to a new culture with its new expectations on the norm obedience also created changes in self-esteem. Exile situation tends to generate

  3. Co-operative agreements and the EU Water Framework Directive in conjunction with the Common Agricultural Policy

    Directory of Open Access Journals (Sweden)

    I. Heinz

    2008-05-01

    Full Text Available This paper discusses the significance of voluntary arrangements for the water and agricultural policies in the European Union. The current implementation of the European Water Framework Directive (WFD and the reform of the Common Agricultural Policy (CAP require new approaches in water management. As many case studies have shown, co-operative agreements (CAs between water companies, farmers and authorities can help to reduce environmental pressures on water bodies. The main reasons for that are: i water companies are ready to advise and financially support farmers in changing production methods; ii changes of farming practices are tailored to the site-specific requirements; iii farmers and water companies are interested in minimising the costs and environmental pressures as they benefit, for example, from modernization of farming methods, and reductions in cost of water treatment, and iv voluntarily agreed commitments to change farming practices are often stricter than statutory rules. Moreover, precautionary rather than remedial measures are preferred. Tackling diffuse pollution is one of the main concerns of the WFD. CAs can enhance the cost-effectiveness of actions within the programmes of measures so that good water status is achieved by 2015. In CAs all relevant stakeholders, located in catchment areas of agricultural usage, can be involved. Thus, they can help to foster integrated water resources management. In particular, disproportionate costs of changing farming practices can be identified. With regard to the recent CAP reform, financial support for farmers will be linked to compliance with environmental standards and further commitments. This concerns both direct payments and agri-environmental programmes. The experience gained in CAs can provide information on best agricultural practices. Informed farmers are more ready to meet environmental requirements. Because CAs implement the most cost-effective changes in farming practice, it

  4. An activatable, polarity dependent, dual-luminescent imaging agent with a long luminescence lifetime.

    Science.gov (United States)

    Rood, Marcus T M; Oikonomou, Maria; Buckle, Tessa; Raspe, Marcel; Urano, Yasuteru; Jalink, Kees; Velders, Aldrik H; van Leeuwen, Fijs W B

    2014-09-04

    In this proof-of-concept study, a new activatable imaging agent based on two luminophores and two different quenching mechanisms is reported. Both partial and total activation of the luminescence signal can be achieved, either in solution or in vitro. Bond cleavage makes the compound suitable for luminescence lifetime imaging.

  5. A thermo-responsive supramolecular organogel: dual luminescence properties and luminescence conversion induced by Cd(2+).

    Science.gov (United States)

    Ma, Xinxian; Zhang, Jinjin; Tang, Ning; Wu, Jincai

    2014-12-14

    A simple dual luminescent acylhydrazone-functionalized benzimidazole derivative (L) was blended with ethylene glycol affording a thermo-responsive green-light-emitting supramolecular gel (G-gel). This G-gel can convert to a blue-light-emitting gel (B-gel) by strongly increasing the luminescence of the benzimidazole moiety upon addition of one equivalent of Cd(2+).

  6. Constructing Interfacial Energy Transfer for Photon Up- and Down-Conversion from Lanthanides in a Core-Shell Nanostructure.

    Science.gov (United States)

    Zhou, Bo; Tao, Lili; Chai, Yang; Lau, Shu Ping; Zhang, Qinyuan; Tsang, Yuen Hong

    2016-09-26

    We report a new mechanistic strategy for controlling and modifying the photon emission of lanthanides in a core-shell nanostructure by using interfacial energy transfer. By taking advantage of this mechanism with Gd(3+) as the energy donor, we have realized efficient up- and down-converted emissions from a series of lanthanide emitters (Eu(3+) , Tb(3+) , Dy(3+) , and Sm(3+) ) in these core-shell nanoparticles, which do not need a migratory host sublattice. Moreover, we have demonstrated that the Gd(3+) -mediated interfacial energy transfer, in contrast to energy migration, is the leading process contributing to the photon emission of lanthanide dopants for the NaGdF4 @NaGdF4 core-shell system. Our finding suggests a new direction for research into better control of energy transfer at the nanometer length scale, which would help to stimulate new concepts for designing and improving photon emission of the lanthanide-based luminescent materials.

  7. Thou should not know too much. When lack of information promotes co-operative behaviour. The case of oil-fields in Wyoming, Oklahoma and Texas

    Energy Technology Data Exchange (ETDEWEB)

    Hassler, B.

    1997-12-31

    Proper assumptions of information levels are of vital importance in all kinds of analysis of interdependent decision-making. In most cases the rule is; the more information the better. In this paper, however, it is shown that such is not always the case. Lack of information can enhance resource utilisation of resources, when the problem of co-operation is of a Prisoner`s dilemma type, and when iteration of the interaction game is unlikely. The case of oil-fields in the United States has been chosen as an empirical example of the latter. Optimal drilling procedures tend to be chosen more often the less the drillers know about the resource characteristics. This outcome is explained by the structure of the decision-making problem, where low levels of information render it advantageous to choose co-operative strategies 16 refs, 4 figs

  8. Theoretical Foundations of the Web: Cognition, Communication, and Co-Operation. Towards an Understanding of Web 1.0, 2.0, 3.0

    Directory of Open Access Journals (Sweden)

    Robert Bichler

    2010-02-01

    Full Text Available Currently, there is much talk of Web 2.0 and Social Software. A common understanding of these notions is not yet in existence. The question of what makes Social Software social has thus far also remained unacknowledged. In this paper we provide a theoretical understanding of these notions by outlining a model of the Web as a techno-social system that enhances human cognition towards communication and co-operation. According to this understanding, we identify three qualities of the Web, namely Web 1.0 as a Web of cognition, Web 2.0 as a Web of human communication, and Web 3.0 as a Web of co-operation. We use the terms Web 1.0, Web 2.0, Web 3.0 not in a technical sense, but for describing and characterizing the social dynamics and information processes that are part of the Internet.

  9. The Realization of Command Channel-Mechanism in a System for Human to Human Interaction and Co-operative%人人交互与协作系统中命令通道机制的实现

    Institute of Scientific and Technical Information of China (English)

    田友胜; 侯义斌

    2000-01-01

    The concept of command channel-mechanism has been introduced into the command channelmechanism system for human to human interaction and co-operative over the Internet/Intranet.A new type of interaction and co-operative environment has been built up.This paper discusses the running mechanism and software realization of the command channel.

  10. 警检配合与侦查监督%Co-operation between the Police and the Procurator and the Investigation Supervision

    Institute of Scientific and Technical Information of China (English)

    周标龙

    2012-01-01

    The Criminal Procedure Law of China stipulates that the police and the procurator should co-operate with each other and that the procurator supervises the investigating activities by the police. However there exists contradiction between the "co- operation" and the "supervision".. if the co-operation between the police and the procurator is strengthened, the function of su- pervision to the investigative power will be weakened; if the supervision to the investigative power is strengthened, the co-oper- ation between the police and the procurator will not work well. We ought to design a mode of relationship between the police and the procurator that the police and the procurator co-operate with each other intensely in order to complete the mission of crime control. At the same , it's necessary to strengthen the checking mechanism to the investigation power of the police.%我国刑事诉讼法规定公安机关与检察机关应当互相配合,同时规定检察机关对公安机关侦查活动进行监督。然而,警检配合与侦查监督具有矛盾性:加强警检配合会削弱侦查监督;加强侦查监督则会使警检难以相互配合。我国应以提高对犯罪的有效追诉为目标构建相互配合与协作的警检关系。同时,应当完善侦查权制约机制以防止侦查权的滥用。

  11. H.S.H. Prince Radu of Hohenzollern-Veringen, Special Representative of the Romanian Government for Integration, Co-operation and Sustainable Development

    CERN Multimedia

    Maximilien Brice

    2002-01-01

    H.S.H. Prince Radu of Hohenzollern-Veringen, Special Representative of the Romanian Government for Integration, Co-operation and Sustainable Development (third from left) with (left to right) Florian Ciolacu (Romanian Mission in Geneva), Cornel Comsa (personal adviser to the Prince), Sorin Ilie (CERN), Calin Alexa (ATLAS), Iosif Legrand (Caltech/CMS), Mihaela Gheata (ALICE), Andrei Gheata (ALICE), and Sorin Zgura (ALICE).

  12. Frequency down-conversion of 637 nm light to the telecommunication band for non-classical light emitted from NV centers in diamond.

    Science.gov (United States)

    Ikuta, Rikizo; Kobayashi, Toshiki; Yasui, Shuto; Miki, Shigehito; Yamashita, Taro; Terai, Hirotaka; Fujiwara, Mikio; Yamamoto, Takashi; Koashi, Masato; Sasaki, Masahide; Wang, Zhen; Imoto, Nobuyuki

    2014-05-05

    We demonstrate a low-noise frequency down-conversion of photons at 637 nm to the telecommunication band at 1587 nm by the difference frequency generation in a periodically-poled lithium niobate. An internal conversion efficiency of the converter is estimated to be 0.44 at the maximum which is achieved by a pump power of 0.43 W, whereas a rate of internal background photons caused by the strong cw pump laser is estimated to be 9 kHz/mW within a bandwidth of about 1 nm. By using the experimental values related to the intrinsic property of the converter, and using the intensity correlation and the average photon number of a 637 nm input light pulse, we derive the intensity correlation of a converted telecom light pulse. Then we discuss feasibility of a single-photon frequency conversion to the telecommunication band for a long-distance quantum communication based on NV centers in diamond.

  13. Strengthening the Radiation Protection System in Cuba (SRPS - Cuba). A co-operation project between Cuban and Swedish institutions, February 2001 - June 2003

    Energy Technology Data Exchange (ETDEWEB)

    Avila, Rodolfo; Larsson, Carl-Magnus; Prendes, Miguel; Zerquera, Juan Tomas

    2004-02-01

    This project results from the co-operation between a number of Cuban and Swedish institutions. It started in February 2001 and ended in June 2003 and was made possible thanks to the contributions of the Swedish International Development Co-operation Agency (SIDA), the Centro de Proteccion e Higiene de las Radiaciones, Cuba (CPHR), and the Swedish Radiation Protection Authority (SSI). The overall objective was to strengthen the radiation protection system in Cuba, and in this way contribute with the control and reduction of risks to man and the environment from exposures to ionizing radiation. The project focused on four priority areas: 1) Protection of workers and patients exposed to radiation in radiation practices; 2) Preparedness for response to an emergency situation; 3) Environmental radiological protection; and, 4) Exposure to radiation in areas with high levels of natural radioactivity. The present report summarizes the findings of the whole project period, providing an overview of the overall achievements, as well as listing its deliverables. The results of an evaluation of the project, conducted during the final workshop, are also included. The report ends with a list of generic and specific conclusions and recommendations for implementation of the project's achievements and for further development of co-operation.

  14. 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...

  15. “Not Just an Apartment Building”: Residents’ Quality of Life in a Social Housing Co-operative

    Directory of Open Access Journals (Sweden)

    Angela Eileen Wisniewski

    2010-01-01

    Full Text Available The objective of this study was to examine the impact that two social housing complexes have had on their residents' quality of life. These two complexes, known as Tannery Court Co-operative Ltd., target a specific segment of the affordable housing market: non-elderly singles. A mixed-methods approach was used to assess the quality of life of residents. The data collection strategy used semi-structured interviews conducted with the help of a questionnaire. A total of 43 interviews were completed at the two building sites. Analysis of interview and questionnaire data identified six areas of improvement in residents' quality of life. These are life in general (an overarching dimension, housing (the focus of the Tannery Court intervention, neighbourhood (including safety and appearance, food, self-confidence (an enabling dimension for future development of projects and goals among the residents, and financial situation (a key dimension because of its multiple impacts on other aspects of life. / L'objectif de cette recherche était d'évaluer l'impact des deux complexes de logements coopératifs Tannery Court sur la qualité de vie des résidants. Ces complexes ciblent un segment particulier du marché du logement social, les célibataires d'âge actif et vivant en deçà du seuil de la pauvreté. Cette étude utilise une méthodologie mixte pour évaluer la situation et la qualité de vie des résidants. La stratégie de cueillette de données s'appuie sur des entrevues semi-dirigées effectuées à l'aide d'un questionnaire. Au total, nous avons complété 43 entrevues. Six aspects de la qualité de vie se sont améliorés de façon significative. Il s'agit de la vie en général (une dimension globale, le logement (l'objectif premier visé par l'équipe de Tannery Court, le quartier de résidence (dimensions importantes de la localisation d'un complexe comme la sécurité et l'apparence la confiance en soi (une dimension clé pour le d

  16. 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

  17. Luminescence kinetics of phosphors after excitation by electron beam

    OpenAIRE

    Ваганов, Виталий; Полисадова, Елена Фёдоровна; Мархабаева, А. А.

    2016-01-01

    The luminescence decay of industrial phosphors based on yttrium-aluminum garnet has beeninvestigated at the excitation by an electron beam. The ratio of slow and fast component amplitude in the kinetics of luminescence decay was estimated. It is shown that the luminescence decay time depends on the composition of the phosphor. The luminescence decay time can be used for analysis of the phosphors, to determine their quality.

  18. Progress in phosphors and filters for luminescent solar concentrators

    OpenAIRE

    De Boer, D.K.G.; Broer, D. J.; Debije, M.G.; Keur, W.; Meijerink, A.|info:eu-repo/dai/nl/075044986; Ronda, R.C.; Verbunt, P.P.C.

    2012-01-01

    Luminescent solar concentrators would allow for high concentration if losses by reabsorption and escape could be minimized. We introduce a phosphor with close-to-optimal luminescent properties and hardly any reabsorption. A problem for use in a luminescent concentrator is the large scattering of this material; we discuss possible solutions for this. Furthermore, the use of broad-band cholesteric filters to prevent escape of luminescent radiation from this phosphor is investigated both experim...

  19. Time-resolved luminescence spectra of porous Si

    OpenAIRE

    Miyoshi, Tadaki; Lee, Kyu-Seok; Aoyagi, Yoshinobu

    1992-01-01

    Time-resolved luminescence spectra of porous Si were measured under an N_2 laser excitation. The luminescence shows a nonexponential decay with an initial time constant of less than 5 ns and more than 200 ns for the secondary decay. The luminescence is considered to be associated with localized states, which are probably conduction and valence sublevels in Si microstructures.

  20. Progress in phosphors and filters for luminescent solar concentrators

    NARCIS (Netherlands)

    de Boer, D.K.G.; Broer, D.J.; Debije, M.G.; Keur, W.; Meijerink, A.; Ronda, R.C.; Verbunt, P.P.C.

    2012-01-01

    Luminescent solar concentrators would allow for high concentration if losses by reabsorption and escape could be minimized. We introduce a phosphor with close-to-optimal luminescent properties and hardly any reabsorption. A problem for use in a luminescent concentrator is the large scattering of

  1. Progress in phosphors and filters for luminescent solar concentrators

    NARCIS (Netherlands)

    De Boer, D.K.G.; Broer, D.J.; Debije, M.G.; Keur, W.C.; Meijerink, A.; Ronda, C.R.; Verbunt, P.P.C.

    2012-01-01

    Luminescent solar concentrators would allow for high concentration if losses by reabsorption and escape could be minimized. We introducea phosphor with close-to-optimal luminescent properties and hardlyany reabsorption. A problem for use in a luminescent concentrator isthe large scattering of this

  2. Progress in phosphors and filters for luminescent solar concentrators

    NARCIS (Netherlands)

    De Boer, D.K.G.; Broer, D.J.; Debije, M.G.; Keur, W.C.; Meijerink, A.; Ronda, C.R.; Verbunt, P.P.C.

    2012-01-01

    Luminescent solar concentrators would allow for high concentration if losses by reabsorption and escape could be minimized. We introducea phosphor with close-to-optimal luminescent properties and hardlyany reabsorption. A problem for use in a luminescent concentrator isthe large scattering of this m

  3. Luminescence engineering in plasmonic meta-surfaces

    CERN Document Server

    Roy, Tapashree; Zheludev, Nikolay I

    2016-01-01

    Photoluminescence is a phenomenon of significant interest due to its wide range of technological applications in plasmonics, nanolasers, spasers, lasing spasers, loss compensation and gain in metamaterials, and luminescent media. Nanostructured materials are known to have very different luminescence characteristics to bulk samples or planar films. Here we show that by engineering a nanostructured meta-surface, we can choose the position of photoluminescence absorption and emission lines of thin gold films. The nanostructuring also aids to strong enhancement of the emission from gold, by a factor of 76 in our experiments. This enhancement is determined by the relative position of the engineered absorption and emission lines to the exciting laser wavelength and the intrinsic properties of the constituent material. These luminescence-engineered materials combined with a resonant material, as in the lasing spaser, or with the power of reconfigurable metamaterials promise huge potential as tunable nanoscale light ...

  4. Luminescence properties of dilute bismide systems

    Energy Technology Data Exchange (ETDEWEB)

    Breddermann, B., E-mail: benjamin.breddermann@physik.uni-marburg.de [Faculty of Physics, Philipps-Universität Marburg, 35032 Marburg (Germany); Bäumner, A.; Koch, S.W.; Ludewig, P.; Stolz, W.; Volz, K. [Faculty of Physics, Philipps-Universität Marburg, 35032 Marburg (Germany); Hader, J.; Moloney, J.V. [Nonlinear Control Strategies Inc, 3542 N. Geronimo Ave., Tucson, AZ 85705 (United States); Broderick, C.A.; O' Reilly, E.P. [Tyndall National Institute, Lee Maltings, Dyke Parade, Cork (Ireland); Department of Physics, University College Cork, Cork (Ireland)

    2014-10-15

    Systematic photoluminescence measurements on a series of GaBi{sub x}As{sub 1−x} samples are analyzed theoretically using a fully microscopic approach. Based on sp{sup 3}s{sup ⁎} tight-binding calculations, an effective k·p model is set up and used to compute the band structure and dipole matrix elements for the experimentally investigated samples. With this input, the photoluminescence spectra are calculated using a systematic microscopic approach based on the semiconductor luminescence equations. The detailed theory-experiment comparison allows us to quantitatively characterize the experimental structures and to extract important sample parameters. - Highlights: • Measurement of photoluminescence spectra of a home grown series of dilute bismides. • Fully microscopic calculation of luminescence spectra from detailed band structure. • Quantitative experiment-theory comparison of luminescence spectra. • Thorough understanding of optoelectronic properties of dilute bismide material system. • Promising perspectives for the development of new device applications.

  5. Luminescent iridium complexes for detection of molybdate.

    Science.gov (United States)

    Castillo, Carmen E; Davies, David L; Klair, Anne-K Duhme; Singh, Kuldip; Singh, Shalini

    2012-01-14

    Reactions of [Ir(C^N)(2)Cl](2) [HC^N = 2-(3-R-phenyl)pyridine, 2-(3-R-phenylpyrazole) R = H, Me] with Me(2)-phencat give luminescent complexes [Ir(C^N)(2)(Me(2)-phencat)][PF(6)] (Me(2)-2a, b, c)[PF(6)]. Deprotection of the methoxy groups with BBr(3) is problematic as simultaneous bromination of the cyclometallated phenyl groups occurs. However, deprotection of Me(2)-phencat with BBr(3) followed by complexation with [Ir(C^N)(2)Cl](2) gives luminescent complexes [Ir(C^N)(2)(H(2)-phencat)][PF(6)] (H(2)-3a, c)[PF(6)], which are luminescent sensors for molybdate.

  6. Spectral luminescence analysis of amniotic fluid

    Science.gov (United States)

    Slobozhanina, Ekaterina I.; Kozlova, Nataly M.; Kasko, Leonid P.; Mamontova, Marina V.; Chernitsky, Eugene A.

    1997-12-01

    It is shown that the amniotic fluid has intensive ultra-violet luminescence caused by proteins. Along with it amniotic fluid radiated in the field of 380 - 650 nm with maxima at 430 - 450 nm and 520 - 560 nm. The first peak of luminescence ((lambda) exc equals 350 nm; (lambda) em equals 430 - 440 nm) is caused (most probably) by the presence in amniotic fluid of some hormones, NADH2 and NADPH2. A more long-wave component ((lambda) exc equals 460 nm; (lambda) em equals 520 - 560 nm) is most likely connected with the presence in amniotic fluid pigments (bilirubin connected with protein and other). It is shown that intensity and maximum of ultra-violet luminescence spectra of amniotic fluid in normality and at pathology are identical. However both emission spectra and excitation spectra of long-wave ((lambda) greater than 450 nm) luminescence of amniotic fluid from pregnant women with such prenatal abnormal developments of a fetus as anencephaly and spina bifida are too long-wave region in comparison with the norm. Results of research testify that spectral luminescent analysis of amniotic fluid can be used for screening of malformations of the neural tube. It is very difficult for a practical obstetrician to reveal pregnant women with a high risk of congenital malformations of the fetus. Apart from ultrasonic examination, cytogenetic examination of amniotic fluid and defumination of concentrations of alpha-fetoprotein and acetylcholin-esterases in the amniotic fluid and blood plasma are the most widely used diagnostic approaches. However, biochemical and cytogenetic diagnostic methods are time-consuming. In the present work spectral luminescence properties of the amniotic fluid are investigated to determine spectral parameters that can be used to reveal pregnant women with a high risk of congenital malformations of their offsprings.

  7. Optically stimulated luminescence in retrospective dosimetry

    DEFF Research Database (Denmark)

    Bøtter-Jensen, L.; Murray, A.S.

    2002-01-01

    Since the beginning of the 1990s the exploration of optically stimulated luminescence (OSL) in retrospective accident dosimetry has driven an intensive investigation and development programme at Riso into measurement facilities and techniques. This paper reviews some of the outcomes of this progr......Since the beginning of the 1990s the exploration of optically stimulated luminescence (OSL) in retrospective accident dosimetry has driven an intensive investigation and development programme at Riso into measurement facilities and techniques. This paper reviews some of the outcomes...

  8. Progress in phosphors and filters for luminescent solar concentrators.

    Science.gov (United States)

    de Boer, Dick K G; Broer, Dirk J; Debije, Michael G; Keur, Wilco; Meijerink, Andries; Ronda, Cees R; Verbunt, Paul P C

    2012-05-07

    Luminescent solar concentrators would allow for high concentration if losses by reabsorption and escape could be minimized. We introduce a phosphor with close-to-optimal luminescent properties and hardly any reabsorption. A problem for use in a luminescent concentrator is the large scattering of this material; we discuss possible solutions for this. Furthermore, the use of broad-band cholesteric filters to prevent escape of luminescent radiation from this phosphor is investigated both experimentally and using simulations. Simulations are also used to predict the ultimate performance of luminescent concentrators.

  9. Combined up conversion, down conversion and down shifting photo-luminescence of low cost erbium-ytterbium co-doped porous silicon produced by stain etching

    Energy Technology Data Exchange (ETDEWEB)

    Diaz-Herrera, B. [Departamento de Fisica Basica, Universidad de La Laguna (ULL), Avenida Astrofisico Francisco Sanchez, 2, 38206 La Laguna, S/C de Tenerife (Spain); Linsun Power Technology (Quanzhou) Corp. Ltd. Co., Economic Development Zone, Jinjiang 362200, Fujian (China); Jimenez-Rodriguez, E. [Departamento de Fisica Basica, Universidad de La Laguna (ULL), Avenida Astrofisico Francisco Sanchez, 2, 38206 La Laguna, S/C de Tenerife (Spain); Gonzalez-Diaz, B. [Departamento de Fisica Basica, Universidad de La Laguna (ULL), Avenida Astrofisico Francisco Sanchez, 2, 38206 La Laguna, S/C de Tenerife (Spain); Instituto Tecnologico y de Energias Renovables, S.A. (ITER), Poligono Industrial de Granadilla, S/N, E38600, Granadilla de Abona (Spain); Montesdeoca-Santana, A. [Departamento de Fisica Basica, Universidad de La Laguna (ULL), Avenida Astrofisico Francisco Sanchez, 2, 38206 La Laguna, S/C de Tenerife (Spain); Velazquez, J.J. [Departamento de Fisica Fundamental y Experimental, Electronica y Sistemas, Avenida Astrofisico Francisco Sanchez, 2, 38206 La Laguna, S/C de Tenerife (Spain); Guerrero-Lemus, R., E-mail: rglemus@ull.es [Departamento de Fisica Basica, Universidad de La Laguna (ULL), Avenida Astrofisico Francisco Sanchez, 2, 38206 La Laguna, S/C de Tenerife (Spain); Fundacion de Estudios de Economia Aplicada, Programa Focus-Abengoa de Energia y Cambio Climaticoi, Jorge Juan 46, 28001 Madrid (Spain)

    2011-07-01

    In this work, erbium and ytterbium have been incorporated into luminescent porous silicon (PS) layers by simple impregnation of the PS substrate with a saturated nitrate solution of erbium and ytterbium. The photoluminescence of the co-doped rare earth layers have been evaluated. The doping process has been designed for its potential in silicon-based solar cell production, with the aim to improve the Shockley-Queisser limit with a reasonable cost effective method for the industry, which implies a significant enhancement of the efficiency under non-concentrated sunlight irradiation. The temperature and annealing time of the doping process were selected according to industry standards in order to ease a trial adoption. The composition was analyzed by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy in order to characterize the doping profile. Different up-conversion and down-conversion contributions from the rare earths in the visible and IR were detected, together with the down shifting effect of the stain etched PS. There is no evidence of energy transference between the PS matrix and the rare earths.

  10. Similarities and differences of doctor-patient co-operated evidence-based medical record of treating digestive system diseases with integrative medicine compared with traditional medical records

    Institute of Scientific and Technical Information of China (English)

    Bo Li; Wen-Hong Shao; Yan-Da Li; Ying-Pan Zhao; Qing-Na Li; Zhao Yang; Hong-Cai Shang

    2016-01-01

    Objective: To establish the model of doctor-patient cooperated record, based on the concepts of narrative evidence-based medicine and related theories on Doctor-Patient Co-operated Evidence-Based Medical Record. Methods: We conducted a literature search from Pubmed, following the principles of narrative evidence-based medicine, and refer to the advice of experts of digestive system and EBM in both traditional Chinese medicine and Western medicine. Result: This research is a useful attempt to discuss the establishment of doctor-patient co-operated evidence-based medical record guided by narrative evidence-based medicine. Conclusion:Doctor-patient co-operated medical record can become a key factor of the curative effect evaluation methodology system of integrated therapy of tradition Chinese medicine and Western medicine on spleen and stomach diseases.%遵循叙事循证医学理念,咨询中西医消化内科及循证医学专家,凝练医患共建式病历的理论,建立医患共建式病历的范本,对比医患共建式病历与传统病历记录的不同,分析医患共建式病历的优缺点。思考与展望:医患共建式病历有可能成为中西医合作治疗脾胃病疗效评价方法学体系的一个要素。

  11. Co-operation between Large Enterprises (LE’s and SME’s: an Approach to Overcome the Stage Internationalization Process

    Directory of Open Access Journals (Sweden)

    Eurico Brilhante Dias

    2014-12-01

    Full Text Available Many companies are using their networks in order to overcome psychic distance – liability of foreignness – and liability of outsidership; and networks at domestic markets can be a base in which SMEs can find a lever to get a rapid internationalization process. Regarding this topic has been developed a case study in the Polish market, where a local retailer (“Biedronka” owned by a Portuguese group (“Jerónimo Martins” is offering Portuguese products. In order to apply a constructivist methodology, using the case study method, five SMEs where selected in order to understand if co-operation between these companies and a LE (Large Enterprise would be a way in order to overcome the liability of foreignness and the liability of outsidership. It was also our purpose the understanding of which are the main issues that promote insidership and also the promotion of a rapid internationalization. Our conclusions have shown a LE as a source of institutional and market-specific knowledge, and regarding this last type of knowledge, as source of opportunities, and also how a SME with internationalization knowledge, an international focus and adaptation skills (in order to adapt products and prices can introduce in a co-operative international venture, in far psychic markets, the ingredients needed to get a successful and rapid entry in a foreign market. Trust as a resource, accumulated during lasting relationships in the domestic market, has been shown as a basic requirement to develop these co-operative approaches in international markets.

  12. Extensive co-operation between the Epstein-Barr virus EBNA3 proteins in the manipulation of host gene expression and epigenetic chromatin modification.

    Directory of Open Access Journals (Sweden)

    Robert E White

    Full Text Available Epstein-Barr virus (EBV is able to drive the transformation of B-cells, resulting in the generation of lymphoblastoid cell lines (LCLs in vitro. EBV nuclear proteins EBNA3A and EBNA3C are necessary for efficient transformation, while EBNA3B is dispensable. We describe a transcriptome analysis of BL31 cells infected with a series of EBNA3-knockout EBVs, including one deleted for all three EBNA3 genes. Using Affymetrix Exon 1.0 ST microarrays analysed with the MMBGX algorithm, we have identified over 1000 genes whose regulation by EBV requires one of the EBNA3s. Remarkably, a third of the genes identified require more than one EBNA3 for their regulation, predominantly EBNA3C co-operating with either EBNA3B, EBNA3A or both. The microarray was validated by real-time PCR, while ChIP analysis of a selection of co-operatively repressed promoters indicates a role for polycomb group complexes. Targets include genes involved in apoptosis, cell migration and B-cell differentiation, and show a highly significant but subtle alteration in genes involved in mitosis. In order to assess the relevance of the BL31 system to LCLs, we analysed the transcriptome of a set of EBNA3B knockout (3BKO LCLs. Around a third of the genes whose expression level in LCLs was altered in the absence of EBNA3B were also altered in 3BKO-BL31 cell lines.Among these are TERT and TCL1A, implying that EBV-induced changes in the expression of these genes are not required for B-cell transformation. We also identify 26 genes that require both EBNA3A and EBNA3B for their regulation in LCLs. Together, this shows the complexity of the interaction between EBV and its host, whereby multiple EBNA3 proteins co-operate to modulate the behaviour of the host cell.

  13. H.S.H. Prince Radu of Hohenzollern-Veringen, Special Representative of the Romanian Government for Integration, Co-operation and Sustainable Development

    CERN Multimedia

    Maximilien Brice

    2002-01-01

    H.S.H. Prince Radu of Hohenzollern-Veringen, Special Representative of the Romanian Government for Integration, Co-operation and Sustainable Development, is seen here visiting Microcosm, CERN's on-site exhibition centre. Photo 01: H.S.H. Prince Radu of Hohenzollern-Veringen (right) with his personal adviser Cornel Comsa inside Microcosm's full-scale model of a six-metre section of the LHC. Photos 04-06: H.S.H. Prince Radu of Hohenzollern-Veringen with Emma Sanders from ETT Division.

  14. A European union (EU) co-operation program: Integral, innovative, industrial product design and development, I3PD(2) and project led education (PLE)

    DEFF Research Database (Denmark)

    Nielsen, Sven Hvid

    2007-01-01

    Aalborg University's project-organised and problem-oriented studies were introduced Thirty-three years ago. The experience since then has proved this to be an important innovation in higher education. The primary aim is to teach young people, students to become useful members for industry...... and society. Other primary objectives are to ensure high-quality research and education and to enhance technology transfer and to stimulate industry-university partnerships within the EU and stimulate Inter-University co-operation programmes. In this project we are focusing on the importance of curriculum...

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

    Science.gov (United States)

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

    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.

  16. Structural changes and relaxations monitored by luminescence.

    Science.gov (United States)

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

    2013-01-01

    Luminescence data have often been used to study imperfections and to characterize lattice distortions because the signals are sensitive to changes of structure and composition. Previous studies have included intentionally added probe ions such as rare earth ions to sense distortions in local crystal fields caused by modified structural environments. An under-exploited extension of this approach was to use luminescence to monitor crystalline phase changes. A current overview of this new and powerful technique shows that continuous scanning of the sample temperatures immediately offered at least three types of signatures for phase transitions. Because of high sensitivity, luminescence signals were equally responsive to structural changes from inclusions and nanoparticles. These coupled to the host material via long-range interactions and modified the host signals. Two frequently observed examples that are normally overlooked are from nanoparticle inclusions of water and CO2. Examples also indicated that phase transitions were detected in more diverse materials such as superconductors and fullerenes. Finally, luminescence studies have shown that in some crystalline examples, high dose ion implantation of surface layers could induce relaxations and/or structural changes of the entire underlying bulk material. This was an unexpected result and therefore such a possibility has not previously been explored. However, the implications for ion implication are significant and could be far more general than the examples mentioned here.

  17. Thermal History Using Microparticle Trap Luminescence

    Science.gov (United States)

    2012-06-01

    34 2008 IEEE/ LEOS Optical MEMS and Nanophotonics Conference, Freiburg Germany, August 2008, pp. 64- 65. 3. J. R. Hazelton, E. G. Yukihara, M. W. Blair...A.J.J. , Prokic, M. and Brouwer , J.C., 2006. Optically and thermally stimulated luminescence characteristics of MgO:Tb3+. Radiat. Prot. Dosim. 119

  18. 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...

  19. Optically stimulated luminescence techniques in retrospective dosimetry

    DEFF Research Database (Denmark)

    Bøtter-Jensen, L.; Murray, A.S.

    2001-01-01

    Optically stimulated luminescence signals from natural quartz and feldspar are now used routinely in dating geological and archaeological materials. More recently they have also been employed in accident dosimetry, i.e. the retrospective assessment of doses received as a result of a nuclear...

  20. Dehydration-induced luminescence in clay minerals

    Science.gov (United States)

    Coyne, L. M.; Lahav, N.; Lawless, J. G.

    1981-01-01

    Reports of triboluminescent phenomena in organic crystalline materials prompted a search for related processes in clay minerals. The reported extensive mechanical distortion produced on freezing and drying of montmorillonite was particularly interesting because of studies of condensation reactions in a wet/dry cycled reaction sequence. The discovery of an unusual luminescent process in several clay minerals is reported and its characteristics are described.

  1. Optically stimulated luminescence dating of young sediments

    DEFF Research Database (Denmark)

    Madsen, A.T.; Murray, A.S.

    2009-01-01

    Optically stimulated luminescence (OSL) dating of young (< 1000 years) sediments is used increasingly in a wide variety of late-Holocene studies as a mean of establishing contemporary sedimentation rates or the timing of sediment deposition. This paper provides a summary of the basic principles o...

  2. Modeling Light Propagation in Luminescent Media

    Science.gov (United States)

    Sahin, Derya

    This study presents physical, computational and analytical modeling approaches for light propagation in luminescent random media. Two different approaches are used, namely (i) a statistical approach: Monte-Carlo simulations for photon transport and (ii) a deterministic approach: radiative transport theory. Both approaches account accurately for the multiple absorption and reemission of light at different wavelengths and for anisotropic luminescence. The deterministic approach is a generalization of radiative transport theory for solving inelastic scattering problems in random media. We use the radiative transport theory to study light propagation in luminescent media. Based on this theory, we also study the optically thick medium. Using perturbation methods, a corrected diffusion approximation with asymptotically accurate boundary conditions and a boundary layer solution are derived. The accuracy and the efficacy of this approach is verified for a plane-parallel slab problem. In particular, we apply these two approaches (MC and radiative transport theory) to model light propagation in semiconductor-based luminescent solar concentrators (LSCs). The computational results for both approaches are compared with each other and found to agree. The results of this dissertation present practical and reliable techniques to use for solving forward/inverse inelastic scattering problems arising in various research areas such as optics, biomedical engineering, nuclear engineering, solar science and material science.

  3. Probing luminescence from nonspherical bubble collapse

    NARCIS (Netherlands)

    Ohl, Claus-Dieter

    2002-01-01

    The luminescence from single laser produced cavitation bubbles for varying degrees of asphericity is investigated temporally, spatially, and spectrally. The degree of asphericity is controlled with an adjustable rigid boundary near the bubble. Temporally, single and multiple light emission events ha

  4. Luminescence from Erbium Oxide Grown on Silicon

    Science.gov (United States)

    2002-01-01

    H9.14 Luminescence from erbium oxide grown on silicon E. Nogales’, B. Mrndez , J.Piqueras’, R.Plugaru2 , J. A. Garcfa3 and T. J. Tate4 ’ Universidad ... Complutense de Madrid, Dpto. Ffsica de Materiales, 28040 Madrid, Spain.2Inst. of Microtechnology, Bucharest, Romania.3Universidad del Pais Vasco, Dpto

  5. Energy transfer in Tb3+,Yb3+ codoped Lu2O3 near-infrared downconversion nanophosphors

    Institute of Scientific and Technical Information of China (English)

    LI Li; WEI Xiantao; CHEN Yonghu; GUO Changxin; YIN Min

    2012-01-01

    Tb3+ and Yb3+ codoped Lu2O3 nanophosphors were synthesized by the reverse-strike co-precipitation method.The obtained Lu2O3:Tb3+,Yb3+ nanophosphors were characterized by X-ray diffraction (XRD) and photoluminescence (PL) spectra.The XRD results showed that all the prepared nanophosphors could be readily indexed to pure cubic phase of Lu2O3 and indicated good crystallinity.The Tb3+→Yb3+ energy transfer mechanisms in the UV-blue region in Lu2O3 nanophosphors were investigated.The experimental results showed that the strong visible emission around 543 nm from Tb3+ (5D4→7F5) and near-infrared (NIR) emission around 973 nm from Yb3+ (2F5/2→2F7/2) of LuzO3:Tb3+,Yb3+ nanophosphors were observed under ultraviolet light excitation,respectively.Tb3+ could be effectively excited up to its 4f75d1 state and relaxed down to the 5D4 level,from which the energy was transferred cooperatively to two neighboring Yb3+.The Yb3+concentration dependent luminescent properties and lifetimes of both the visible and NIR emissions were also studied.The lifetime of the visible emission decreased with the increase of Yb3+ concentration,verifying the efficient energy transfer from the Tb3+to the Yb3+.Cooperative energy transfer (CET) from Tb3+ to Yb3+ was discussed as a possible mechanism for the near-infrared emission.When doped concentrations were 1 mol.% Tb3+ and 2 mol.% Yb3+,the intensity of NIR emission was the strongest.

  6. Protocol to the 2001 Co-Operation Agreement between the European Organization For Nuclear Research (CERN) and the Ministry of Science, Technology and Development of the Republic of Serbia

    CERN Document Server

    2001-01-01

    On 8 June 2001, on the basis of the mandate given by Council in 1989 to the Director-General to enter into Co-operation Agreements following a defined text model, CERN and the Government of the Republic of Serbia have entered into a Co-operation Agreement on the further development of scientific and technical co-operation in high-energy physics. As usual, the concrete implementation of the Co-operation Agreement is foreseen to take place through the conclusion of Protocols. Agreement has now been reached on the text of a Protocol concerning the Serbian participation in the CMS Collaboration. Annex I to the Protocol, which defines the technical specification of the Serbian contribution, is still under preparation. Although the Protocol contains no concrete financial commitment by CERN, pending a decision by the Committee of Council on procedures for agreements and protocols, the Management proposes that the Finance Committee takes note of the text of the Protocol.

  7. Co-operation agreement between the European Organization for Nuclear Research (CERN) and the Hachemite Kingdom of Jordan and the Synchrotron-Light for Experimental Science and Applications in the Middle East (SESAME)

    CERN Document Server

    2004-01-01

    Co-operation agreement between the European Organization for Nuclear Research (CERN) and the Hachemite Kingdom of Jordan and the Synchrotron-Light for Experimental Science and Applications in the Middle East (SESAME)

  8. Cooperation Agreement between the European Organization for Nuclear Research (CERN) and The Qatar Foundation for Education, Science and Community Development concerning Scientific and Technical Co-operation in High Energy Physics

    CERN Document Server

    2016-01-01

    Cooperation Agreement between the European Organization for Nuclear Research (CERN) and The Qatar Foundation for Education, Science and Community Development concerning Scientific and Technical Co-operation in High Energy Physics

  9. Synthesis and characterization of Ho{sup 3+}-doped strontium titanate downconversion nanocrystals and its application in dye-sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Li, Y.Y. [Department of Inorganic Nonmetallic Materials Engineering, Dalian Polytechnic University, Dalian 116034 (China); Liaoning Provincial College Key Laboratory of New Materials and Material Modification, Dalian Polytechnic University, Dalian 116034 (China); Hao, H.S., E-mail: beike1952@163.com [Department of Inorganic Nonmetallic Materials Engineering, Dalian Polytechnic University, Dalian 116034 (China); Liaoning Provincial College Key Laboratory of New Materials and Material Modification, Dalian Polytechnic University, Dalian 116034 (China); Qin, L. [National Engineering Research Center of Seafood, Dalian Polytechnic University, Dalian 116034 (China); Wang, H.L.; Nie, M.Q.; Hu, Z.Q.; Gao, W.Y.; Liu, G.S. [Department of Inorganic Nonmetallic Materials Engineering, Dalian Polytechnic University, Dalian 116034 (China); Liaoning Provincial College Key Laboratory of New Materials and Material Modification, Dalian Polytechnic University, Dalian 116034 (China)

    2015-02-15

    Highlights: • A new downconversion (DC) nanocrystal (SrTiO{sub 3}:Ho{sup 3+}) was synthesized. • The effect of SrTiO{sub 3}:Ho{sup 3+} as a photoanode in DSSCs was investigated. • SrTiO{sub 3}:Ho{sup 3+} absorb ultraviolet light and downconvert it to visible light. • DC SrTiO{sub 3}:Ho{sup 3+} as a photoanode achieve the higher photoelectric conversion efficiency. - Abstract: Ho{sup 3+}-doped strontium titanate (SrTiO{sub 3}:Ho{sup 3+}) downconversion (DC) nanocrystals are synthesized by the solid state interaction of titanium dioxide, strontium nitrate, holmium oxide and sodium chloride and then used as a photoanode in dye-sensitized solar cells (DSSCs) to investigate the effect of DC nanocrystals in DSSCs. Differential thermal analysis, X-ray diffraction, scanning electronic microscope, energy dispersive spectroscopy and Brunauer-Emmet-Teller analysis confirmed the formation of cubic structured SrTiO{sub 3}:Ho{sup 3+} nanocrystals with diameters of 40-400 nm, pore size of ∼45 nm, sintering temperature of 950 °C. The photofluorescence and UV-Vis absorption spectra of the SrTiO{sub 3}:Ho{sup 3+} nanocrystals revealed strong emission intensity and visible light absorption when doped content of holmium oxide was between 1 wt% and 3 wt%. Compared with the pure SrTiO{sub 3} photoanode, SrTiO{sub 3}:Ho{sup 3+} DC photoanode showed a greater photovoltaic efficiency. The photoelectric conversion efficiency (η) of the DSSCs with a SrTiO{sub 3}:Ho{sup 3+} photoanode doped with 1 wt% holmium oxide was 59% higher than that with a pure SrTiO{sub 3} photoanode. This phenomenon could be explained by SrTiO{sub 3}:Ho{sup 3+} nanocrystals’ ability to absorb ultraviolet light and downconvert it to visible light, which extends spectral response range of DSSC to the ultraviolet region and increased the short-circuit current density (Jsc) of DSSCs.

  10. Japan-Australia co-operative program on research and development of technology for the management of high level radioactive wastes. Final report 1985 to 1998

    Energy Technology Data Exchange (ETDEWEB)

    Hart, K.; Vance, E.; Lumpkin, G. [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia); Mitamura, H.; Banba, T. [Japan Atomic Energy Research Inst. Tokai, Ibaraki (Japan)

    1998-12-01

    The overall aim of the Co-operative Program has been to promote the exchange of information on technology for the management of High-Level Wastes (HLW) and to encourage research and development relevant to such technology. During the 13 years that the Program has been carried out, HLW management strategies have matured and developed internationally, and Japan has commenced construction of a domestic reprocessing and vitrification facility for HLW. The HLW management strategy preferred is a national decision. Many countries are using vitrification, direct disposal of spent fuel or a combination of both to handle their existing wastes whereas others have deferred the decision. The work carried out in the Co-operative Program provides strong scientific evidence that the durability of ceramic waste forms is not significantly affected by radiation damage and that high loadings of actinide elements can be incorporated into specially designed ceramic waste forms. Moreover, natural minerals have been shown to remain as closed systems for U and Th for up to 2.5 b y. All of these results give confidence in the ability of second generation waste forms, such as Synroc, to handle future waste arisings that may not be suitable for vitrification 87 refs., 15 tabs., 22 figs.

  11. Learning from the Co-operative Institutional Model: How to Enhance Organizational Robustness of Third Sector Organizations with More Pluralistic Forms of Governance

    Directory of Open Access Journals (Sweden)

    Keith Taylor

    2015-08-01

    Full Text Available Third sector organizations are oftentimes seen as contributing to a robust civil society. Yet the dominant modes of third sector organizational governance often adhere to a unitary orientation. The over-reliance on unitary modes of governance introduces two challenges: first, organizational stakeholders are kept from utilizing participatory mechanisms that would enable them to act as societal intermediaries, and; second, these organizations may underperform due to the artificial separation of stakeholders from participating in governance. This paper addresses calls to widen our knowledge by translating theory into practice through a discussion about the efficacy of pluralistic governance. The co-operative enterprise in introduced to focus analyses on pluralist modes of stakeholder governance. A specific co-operative’s governance structure and practice is introduced—Choctaw Electric Co-operative—through an archival analyses of secondary media accounts of a stakeholder-led reform initiative in rural Oklahoma. The Ostrom Design Principles—a diagnostic used to assess institutional robustness—are applied to demonstrate the shortsightedness of unitary governance, and highlight the potential benefits of pluralistic stakeholder engagement. Knowledge is widened in two ways: first, empirical analyses of co-operative enterprise may provide for significant insights and innovations in third sector governance, and; second proper systems of pluralistic governance exhibit enormous capacity to better orient the firm toward better serving the stakeholder base, improving performance and institutional robustness, while empowering stakeholders as societal intermediaries.

  12. Planning of biogas plants. A question of co-operation and negotiation; Planering av biogasanlaeggningar. En fraaga om samverkan och foerhandling

    Energy Technology Data Exchange (ETDEWEB)

    Khan, Jamil

    2003-04-01

    During the last years there has been an increased interest in Sweden to build biogas reactors. The planning of a biogas plant brings about the need for co-operation between a variety of actors. Furthermore, there are a number of different issues that need to be dealt with. To build a biogas plant is thus a rather complicated thing to do. The aim of this report is to increase the knowledge about the processes that precede a decision to build a biogas plant, in order to try to facilitate the planning of future projects. The report is based on case studies of the planning of two biogas plants in Sweden and the empirical material consists of interviews with key persons as well as written documents. In the study, three parallel processes are identified and analysed, which are all crucial to carry through a project. These are the project planning process, the political process and the application process. The most important result of the study is that there is not only one way to carry through a project and that the choice of strategy depends on the character of the project and the different questions that need to be handled. Examples of other results are: the importance of an early and continuous dialogue with the political leadership, the necessity to build an organisation for the co-operation between key actors and that the project leaders should be flexible and open to changes in the project throughout the planning process.

  13. 内镜黏膜切除术的配合体会%Experiences of nursing co-operation during Endoscopic Submucosal Dissection (ESD)

    Institute of Scientific and Technical Information of China (English)

    姜素峰; 韩树堂

    2011-01-01

    目的 探讨内镜黏膜切除术时护理配合治疗.方法 术前给患者心理指导和术前常规准备,并备好各种治疗器械,术中配合术者操作,术后做好健康教育预防并发症的发生.结果 58例胃肠道侧向发育型肿瘤均经内镜切除,成功率100%.结论护士能否在术前、术中和术后做好配合影响内镜下侧向发育型肿瘤切除术的效果.%Objective To explore the role of nursing cooperation during endoscopic submucosal dissection (ESD). Methods Psychological counseling and regular preparation were carried out pre- operationally, co- operation with the operator was done during endoscopic submucosal dissection (ESD), and health education was given to prevent the complications. Results Totally 58 cases of laterally spreading tumor (LST) were resected by endoscopic submucosal dissection (ESD), the successful rate was 100%. Conclusion Whether nursing co-operation was performed skillfully in perioperative period influenced the effects of endoscopic submucosal dissection of laterally spreading tumor (LST).

  14. Intrinsic disorder in the partitioning protein KorB persists after co-operative complex formation with operator DNA and KorA.

    Science.gov (United States)

    Hyde, Eva I; Callow, Philip; Rajasekar, Karthik V; Timmins, Peter; Patel, Trushar R; Siligardi, Giuliano; Hussain, Rohanah; White, Scott A; Thomas, Christopher M; Scott, David J

    2017-08-30

    The ParB protein, KorB, from the RK2 plasmid is required for DNA partitioning and transcriptional repression. It acts co-operatively with other proteins, including the repressor KorA. Like many multifunctional proteins, KorB contains regions of intrinsically disordered structure, existing in a large ensemble of interconverting conformations. Using NMR spectroscopy, circular dichroism and small-angle neutron scattering, we studied KorB selectively within its binary complexes with KorA and DNA, and within the ternary KorA/KorB/DNA complex. The bound KorB protein remains disordered with a mobile C-terminal domain and no changes in the secondary structure, but increases in the radius of gyration on complex formation. Comparison of wild-type KorB with an N-terminal deletion mutant allows a model of the ensemble average distances between the domains when bound to DNA. We propose that the positive co-operativity between KorB, KorA and DNA results from conformational restriction of KorB on binding each partner, while maintaining disorder. © 2017 The Author(s).

  15. 9 May 2008 - Signature of the Protocol to the co-operation agreement dated 21 January 2006 between King Abdulaziz City for Science and Technology (KACST) on behalf of the Government of the Kingdom of Saudi Arabia, represented by M. I. Al-Suwaiyel and the European Organization for Nuclear Research (CERN), represented by R. Aymar, concerning the further development of scientific and technical co-operation in high-energy physics

    CERN Multimedia

    Maximilien Brice

    2008-01-01

    9 May 2008 - Signature of the Protocol to the co-operation agreement dated 21 January 2006 between King Abdulaziz City for Science and Technology (KACST) on behalf of the Government of the Kingdom of Saudi Arabia, represented by M. I. Al-Suwaiyel and the European Organization for Nuclear Research (CERN), represented by R. Aymar, concerning the further development of scientific and technical co-operation in high-energy physics

  16. Theory of filtered type-II parametric down-conversion in the continuous-variable domain: Quantifying the impacts of filtering

    Science.gov (United States)

    Christ, Andreas; Lupo, Cosmo; Reichelt, Matthias; Meier, Torsten; Silberhorn, Christine

    2014-08-01

    Parametric down-conversion (PDC) forms one of the basic building blocks for quantum optical experiments. However, the intrinsic multimode spectral-temporal structure of pulsed PDC often poses a severe hindrance for the direct implementation of the heralding of pure single-photon states or, for example, continuous-variable entanglement distillation experiments. To get rid of multimode effects narrowband frequency filtering is frequently applied to achieve a single-mode behavior. A rigorous theoretical description to accurately describe the effects of filtering on PDC, however, is still missing. To date, the theoretical models of filtered PDC are rooted in the discrete-variable domain and only account for filtering in the low-gain regime, where only a few photon pairs are emitted at any single point in time. In this paper we extend these theoretical descriptions and put forward a simple model, which is able to accurately describe the effects of filtering on PDC in the continuous-variable domain. This developed straightforward theoretical framework enables us to accurately quantify the tradeoff between suppression of higher-order modes, reduced purity, and lowered Einstein-Podolsky-Rosen entanglement, when narrowband filters are applied to multimode type-II PDC.

  17. Dispersion-tolerant two-photon Michelson interferometer using telecom-band frequency-entangled photon pairs generated by spontaneous parametric downconversion

    Science.gov (United States)

    Yoshizawa, Akio; Fukuda, Daiji; Tsuchida, Hidemi; Yamamoto, Noritsugu

    2015-05-01

    The chromatic group velocity dispersion tolerance of a fiber-optic two-photon interferometer is characterized for telecom-band photon pairs that are frequency entangled. Two indium-gallium-arsenide single-photon detectors are used to record the coincidence counts. A single-wavelength laser diode continuously pumps a periodically poled lithium niobate waveguide of 1-mm length. For near-degenerate spontaneous parametric downconversion, it generates wideband entangled collinear photon pairs. The spectral width of 115.8 nm is centered at 1550 nm. It is restricted by the performance of the single-photon detectors whose efficiency is poor beyond 1610 nm. Using a Michelson interferometer, two-photon interference signals are recorded with and without frequency entanglement. The frequency-entangled photon pairs are found to exhibit dispersion-tolerant two-photon interference, even though the two paths through the interferometer have different group velocity dispersion. The observed two-photon interference signal has a correlation time of 42.7 fs, in good agreement with calculations for a 115.8-nm spectral width. For comparison, results are also presented for photon pairs lacking frequency entanglement.

  18. Improved efficiency for nanopillar array of c-Si photovoltaic by down-conversion and anti-reflection of quantum dots

    Science.gov (United States)

    Lin, Chien-chung; Chen, Hsin-Chu; Han, Hau-Vei; Tsai, Yu-Lin; Chang, Chia-Hua; Tsai, Min-An; Kuo, Hao-Chung; Yu, Peichen

    2012-02-01

    Improvement of efficiency for crystalline silicon (c-Si) with nanopillar arrays (NPAs) solar cell was demonstrated by deployment of CdS quantum dots (QDs). The NPAs was fabricated by colloidal lithography of self-assembled polystyrene (PS) nanospheres with a 600 nm in size and reactive-ion etching techniques, and then a colloidal CdS QDs with a concentration of 5 mg/mL was spun on the surface of c-Si with NPAs solar cell. Under a simulated one-sun condition, the device with CdS QDs shows a 33% improvement of power conversion efficiency, compared with the one without QDs. Additionally, we also found that the device with CdS QDs shows a 32% reduction in electrical resistance, compared with the one without QDs solar cell, under an ultraviolet (UV) light of 355nm illumination. This reduced electrical resistance can directly contribute to our fill-factor (FF) enhancement. For further investigation, the excitation spectrum of photoluminescence (PL), absorbance spectrum, current-voltage (I-V) characteristics, reflectance and external quantum efficiency (EQE) of the device were measured and analyzed. Based on the spectral response and optical measurement, we believe that CdS QDs not only have the capability for photon down-conversion in ultraviolet region, but also provide extra antireflection capability.

  19. ZnCuInS/ZnSe/ZnS Quantum Dot-Based Downconversion Light-Emitting Diodes and Their Thermal Effect

    Directory of Open Access Journals (Sweden)

    Wenyan Liu

    2015-01-01

    Full Text Available The quantum dot-based light-emitting diodes (QD-LEDs were fabricated using blue GaN chips and red-, yellow-, and green-emitting ZnCuInS/ZnSe/ZnS QDs. The power efficiencies were measured as 14.0 lm/W for red, 47.1 lm/W for yellow, and 62.4 lm/W for green LEDs at 2.6 V. The temperature effect of ZnCuInS/ZnSe/ZnS QDs on these LEDs was investigated using CIE chromaticity coordinates, spectral wavelength, full width at half maximum (FWHM, and power efficiency (PE. The thermal quenching induced by the increased surface temperature of the device was confirmed to be one of the important factors to decrease power efficiencies while the CIE chromaticity coordinates changed little due to the low emission temperature coefficients of 0.022, 0.050, and 0.068 nm/°C for red-, yellow-, and green-emitting ZnCuInS/ZnSe/ZnS QDs. These indicate that ZnCuInS/ZnSe/ZnS QDs are more suitable for downconversion LEDs compared to CdSe QDs.

  20. Luminescence chronology of a second millenium BCE settlement near Porbandar on the Gujarat coast, India

    Digital Repository Service at National Institute of Oceanography (India)

    Gaur, A.S.; Thomas, P.J.; Vora, K.H.; Sundaresh

    ) and optically stimulated luminescence (OSL) dating of two potshards. The obtained luminescence ages are found to be in agreement with other archaeological findings. The implications of the luminescence ages on the maritime history of the area and the cultural...

  1. Luminescence of Au(I)-thiolate complex affected by solvent

    Science.gov (United States)

    Yang, Lina; Cao, Yuanjie; Chen, Juan; Sun, Zhihu; Yao, Tao; Jiang, Yong; Wei, Shiqiang

    2017-08-01

    This work presents a study on the correlation between luminescence property of Au(I)-SR (SR: thiolate) complexes and solvent polarity. Luminescent [Au15(SR)14-16]+ complexes were synthesized in the weakly polar solvent of toluene, while the non-luminescent [Au7(SR)6]+ species were obtained by the same synthesis method in the polar solvent of ethanol. The dependence of luminescence intensity on the mixed solvent with various toluene/ethanol ratios was also explored. It is proposed that the luminescence of Au(I)-SR complexes originates from the aggregation of the bilayer supramolecular structures induced by the weakly polar solvent. This aggregation strengthens the intra and intercomplex aurophilic Au(I)···Au(I) interactions and subsequently enhances the luminescence intensity of the complexes.

  2. Recent progress in biomedical applications of persistent luminescence nanoparticles.

    Science.gov (United States)

    Wang, Jie; Ma, Qinqin; Wang, Yingqian; Shen, Haijing; Yuan, Quan

    2017-05-18

    Persistent luminescence nanoparticles (PLNPs) are an emerging group of promising luminescent materials that can remain luminescent after the excitation ceases. In the past decade, PLNPs with intriguing optical properties have been developed and their applications in biomedicine have been widely studied. Due to the ultra-long decay time of persistent luminescence, autofluorescence interference in biosensing and bioimaging can be efficiently eliminated. Moreover, PLNPs can remain luminescent for hours, making them valuable in bio-tracing. Also, persistent luminescence imaging can guide cancer therapy with a high signal-to-noise ratio (SNR) and superior sensitivity. Briefly, PLNPs are demonstrated to be a newly-emerging class of functional materials with unprecedented advantages in biomedicine. In this review, we summarized recent advances in the preparation of PLNPs and the applications of PLNPs in biosensing, bioimaging and cancer therapy.

  3. Luminescence studies on europium-strontium phthalate system.

    Science.gov (United States)

    Yang, Limin; Zhao, Ying; Su, Yunlan; Wu, Jinguang

    2002-11-01

    New lanthanide luminescence materials were prepared. The main component lanthanide chelates generally need a relatively high content of rare earth. Inorganic luminescence materials only need low rare earth concentration using doped method. Similarly, lanthanide chelates can be added to complex matrix by doped method. In this way, low rare earth concentration emission was successful in the lanthanide chelates system as well. The influence of europium ion concentration on luminescence intensities was discussed. When the europium ion weight in the complex is only about 0.6%, the sample exhibits good luminescence properties. The fluorescence, Fourier transform infrared spectra, micro-Raman and electron spin resonance spectra of the samples were measured. And a possible luminescence mechanism was suggested by the inorganic doped mechanism and the luminescence of lanthanide complexes together.

  4. Phosphate modulated luminescence in lanthanum vanadate nanorods- Catechin, polyphenolic ligand

    Science.gov (United States)

    Tamilmani, Vairapperumal; Nair, Balachandran Unni; Sreeram, Kalarical Janardhanan

    2017-08-01

    Rare earth orthovanadates and phosphates offer a very high opportunity for fabrication of nanoscale devices that exploit their luminescence properties. Optimization of luminescence by way of modulation of size, shape, structure, and morphology has been an area of study for several researchers. There has been a debate as to whether doped orthophosphate or orthovanadate is better luminescent material as both are chemically similar. It has been reported earlier that catechin hydrate can play the role of a structure director and thus influence the luminescence properties of orthovanadates. In this work, a catechin modulated the synthesis of Eu-doped lanthanum orthophosphate by phosphate substitution into vanadate host lattice is reported. A mechanistic understanding of the luminescence changes in LaMO4 has been proposed. During the substitution of V with P, catechin modulates the structure between 1D nanorods and nanowires. The host crystal structure, shape, and size influence the luminescence properties in doped LaMO4.

  5. New luminescence measurement facilities in retrospective dosimetry

    DEFF Research Database (Denmark)

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

    2012-01-01

    thermoelectrically cooled NIR sensitive PMT (detection window peak at 855 nm, FWHM 27 nm). Software and electronics have been modified to allow standard TL and OSL measurements in the same sequence as RL measurements. Together with a new bleaching source based on a high-power UV LED (395 nm; 700 mW/cm2......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......-uniformity.We first describe improvements to the existing RL option to allow near infra-red detection (NIR) during irradiation by the built-in 90Sr/90Y beta source. The RL optical signal is collected by a liquid light guide through an F34-901 interference filter and detection is based on a dedicated...

  6. 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.

  7. 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...... determined the depositional age of a wide variety of fine-grained sediments, from several years to several hundred thousands of years. However, there is no routine OSL dating method applicable to larger clasts such as cobbles, boulders and other rock surfaces. Here the application of quartz OSL to the dating...... of rock surfaces is successfully tested by application to two different quartz-rich rock types (sandstone and quartzite). Together with the measurement of infrared stimulated luminescence (IRSL) signals as a function of depth into the surface of different granites it is clear that both OSL and IRSL can...

  8. 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.

  9. Materials for luminescent greenhouse solar collectors.

    Science.gov (United States)

    Levitt, J A; Weber, W H

    1977-10-01

    Luminescent greenhouse solar collectors are potentially useful for concentrating sunlight onto photovoltaic power cells. Measurements of the performance of small-scale collectors made of two commercially available materials (Owens-Illinois ED2 neodymium-doped laser glass and rhodamine 6G-doped plastic) are presented. The results are encouraging, but they indicate a need for further spectral sensitization and for reduced matrix loss coefficient. The measurements with monochromatic illumination agree with the predictions of a mathematical model developed to take account of reemission following the absorption of luminescence. Under solar illumination, the model predicts photon flux concentrations of about 15 for optimized full-scale collectors made of the materials studied and concentrations of 110 for reasonably improved glass.

  10. Modeling and simulation of luminescence detection platforms.

    Science.gov (United States)

    Salama, Khaled; Eltoukhy, Helmy; Hassibi, Arjang; El-Gamal, Abbas

    2004-06-15

    Motivated by the design of an integrated CMOS-based detection platform, a simulation model for CCD and CMOS imager-based luminescence detection systems is developed. The model comprises four parts. The first portion models the process of photon flux generation from luminescence probes using ATP-based and luciferase label-based assay kinetics. An optics simulator is then used to compute the incident photon flux on the imaging plane for a given photon flux and system geometry. Subsequently, the output image is computed using a detailed imaging sensor model that accounts for photodetector spectral response, dark current, conversion gain, and various noise sources. Finally, signal processing algorithms are applied to the image to enhance detection reliability and hence increase the overall system throughput. To validate the model, simulation results are compared to experimental results obtained from a CCD-based system that was built to emulate the integrated CMOS-based platform.

  11. Luminescent lanthanide chelates and methods of use

    Science.gov (United States)

    Selvin, Paul R.; Hearst, John

    1997-01-01

    The invention provides lanthanide chelates capable of intense luminescence. The celates comprise a lanthanide chelator covalently joined to a coumarin-like or quinolone-like sensitizer. Exemplary sensitzers include 2- or 4-quinolones, 2- or 4-coumarins, or derivatives thereof e.g. carbostyril 124 (7-amino-4-methyl-2-quinolone), coumarin 120 (7-amino-4-methyl-2-coumarin), coumarin 124 (7-amino-4-(trifluoromethyl)-2-coumarin), aminomethyltrimethylpsoralen, etc. The chelates form high affinity complexes with lanthanides, such as terbium or europium, through chelator groups, such as DTPA. The chelates may be coupled to a wide variety of compounds to create specific labels, probes, diagnostic and/or therapeutic reagents, etc. The chelates find particular use in resonance energy transfer between chelate-lanthanide complexes and another luminescent agent, often a fluorescent non-metal based resonance energy acceptor. The methods provide useful information about the structure, conformation, relative location and/or interactions of macromolecules.

  12. Luminescence from Tube-Arrest Bubbles in Pure Glycerin

    Institute of Scientific and Technical Information of China (English)

    陈岐岱; 王龙

    2004-01-01

    Single transient cavitation bubble with luminescence has been generated in pure glycerin by using the ‘tube arrest'method. The analyses of high-speed photograph and light emission data suggest that the light emission would be a single bubble sonoluminescence. The luminescence pulse width is observed to wry from sub-nanosecond to about 30 ns. The width and intensity of luminescence pulses increases with the height of the liquid column height and decreases with the liquid temperature.

  13. 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.

  14. Luminescence spectra and kinetics of disordered solid solutions

    DEFF Research Database (Denmark)

    Klochikhin, A.; Reznitsky, A.; Permogorov, S.;

    1999-01-01

    We have studied both theoretically and experimentally the luminescence spectra and kinetics of crystalline, disordered solid solutions after pulsed excitation. First, we present the model calculations of the steady-state luminescence band shape caused by recombination of excitons localized in the......-time limit at excitation below the exciton mobility edge. At excitation by photons with higher energies the diffusion of electrons can account for the observed behavior of the luminescence. [S0163-1829(99)11419-X]....

  15. 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)

  16. Thermally stimulated luminescence of urine salts

    Science.gov (United States)

    Bordun, O.; Drobchak, O.

    2008-05-01

    The thermally stimulated luminescence (TSL) of normal and pathological urine was studied. The presence of pathological salts leads to extinguishing of TSL intensity and to the appearance of additional stripes with maxima nearly 118 and 205K, except of characteristic stripes with the maxima nearly 173 and 260K. TSL stripes depend on urine constituents. The comparison of TSL intensity of normal and pathological urine is carried out and energies of thermal activation are determined for most intensive TSL stripes.

  17. Intrinsic luminescence of alkali silicate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Arbuzov, V.I.; Grabovskis, V.Y.; Tolstoi, M.N.; Vitol, I.K.

    1986-09-01

    This study obtains additional information on L centers and their role in electron excitation and intrinsic luminescence of a whole series. (Li, Na, K, Rb, and Cs) of alkali silicate glasses. The authors compare the features of the interaction with radiation of specimens of glass and crystal of a similar chemical composition, since silicates of alkali metals can be obtained in both the glassy and crystalline states.

  18. Eu2+ luminescence in strontium aluminates

    NARCIS (Netherlands)

    Dutczak, D.; Juestel, T.; Ronda, C.; Meijerink, A.

    2015-01-01

    The luminescence properties of Eu2+ doped strontium aluminates are reported and reviewed for a variety of aluminates, viz. SrAl12O19, SrAl4O7, Sr4Al14O25, SrAl2O4 and Sr3Al2O6. The aim of the research is to investigate the role of local coordination and covalency of the aluminate host lattice,

  19. Liquid Contact Luminescence from Semiconductor Laser Materials

    Science.gov (United States)

    1997-01-09

    Luminescence - Diagnostic As a diagnostic tool, LCL can provide much useful information about the quality of the epitaxial wafer prior to laser fabrication . In...diagnostic tool, LCL can provide a variety of useful information about the quality of the epitaxial wafer prior to laser fabrication . Temporal...the quality of the epitaxial laser wafer prior to laser fabrication . It is a quick, inexpensive, and non- destructive process that measures a variety

  20. Exciton luminescence in BaFCl crystal

    Energy Technology Data Exchange (ETDEWEB)

    Radzhabov, E

    1998-05-01

    The luminescence spectra and decay characteristics of both 5.45 and 3.4 eV bands in BaFCl oxygen-free crystals were investigated at 5-300 K temperature range using vacuum ultraviolet excitation as well as X-ray excitation. The similarities with excitons in alkali halides allow us to consider both excitons in BaFCl as on-center excitons and strong off-center excitons.

  1. Spectral converters and luminescent solar concentrators

    CERN Document Server

    Scudo, Petra F; Fusco, Roberto

    2009-01-01

    In this paper we present a comprehensive theoretical description of molecular spectral converters in the specific context of Luminescent Solar Concentrators (LSCs). The theoretical model is an extension to a three-level system interacting with a solar radiation bath of the standard quantum theory of atomic radiative processes. We derive the equilibrium equations of the conversion process and provide specific examples of application of this principle to the development of solar concentration devices.

  2. Eu2+ luminescence in strontium aluminates

    NARCIS (Netherlands)

    Dutczak, D.; Juestel, T.; Ronda, C.; Meijerink, A.

    2015-01-01

    The luminescence properties of Eu2+ doped strontium aluminates are reported and reviewed for a variety of aluminates, viz. SrAl12O19, SrAl4O7, Sr4Al14O25, SrAl2O4 and Sr3Al2O6. The aim of the research is to investigate the role of local coordination and covalency of the aluminate host lattice, relat

  3. Luminescence of erbium ions in tellurite glasses

    Energy Technology Data Exchange (ETDEWEB)

    Savikin, Alexander P.; Grishin, Igor A.; Sharkov, Valery V.; Budruev, Andrei V., E-mail: budruev@gmail.com

    2013-11-15

    Optical characteristics of new generation of tellurite glasses having high stability against crystallization have been studied. As the initial reagents for the glasses synthesis on the base of tellurium oxide (TeO{sub 2}) there were used such oxides as WO{sub 3}, MoO{sub 3}, La{sub 2}O{sub 3}, Li{sub 2}CO{sub 3}, ZnO—Bi{sub 2}O{sub 2}CO{sub 3} and active components such as high purity Er{sub 2}O{sub 3}, Yb{sub 2}O{sub 3}, ErF{sub 3} and YbF{sub 3}. Intensities of luminescence at 1.53 µm of the erbium ions were determined after excitation at 975 nm. Experimental data obtained have shown the possibility to use the studied glasses doped by Er{sup 3+} and Yb{sup 3+} as active elements for fiber and integrated optics. - Graphical abstract: In contrast to the case of ZBLAN glass the TeO{sub 2}–WO{sub 3} (Er{sup 3+}) glass has bright intensity of luminescence at 1.53 µm for erbium ions that should be caused by excitation at 975 nm. Experimental data obtained have shown the possibility to use the studied glasses doped by Er{sup 3+} and Yb{sup 3+} as active elements for fiber and integrated optics. Display Omitted - Highlights: • We examined changes in growth of luminescence in doubly-doped tellurite glasses. • We found that luminescence grows in two orders by using Er{sup 3+} and Yb{sup 3+} at 1.53 μm. • We see possibility to use those glasses as active elements for integrated optics.

  4. Cerenkov luminescence imaging of medical isotopes

    OpenAIRE

    Ruggiero, Alessandro; Holland, Jason P.; Lewis, Jason S.; Grimm, Jan

    2010-01-01

    The development of novel multimodality imaging agents and techniques represents the current frontier of research in the field of medical imaging science. However, the combination of nuclear tomography with optical techniques has yet to be established. Here, we report the use of the inherent optical emissions from the decay of radiopharmaceuticals for Cerenkov luminescence imaging (CLI) of tumors in vivo and correlate the results with those obtained from concordant immuno-PET studies.

  5. Luminescent probes for optical in vivo imaging

    Science.gov (United States)

    Texier, Isabelle; Josserand, Veronique; Garanger, Elisabeth; Razkin, Jesus; Jin, Zhaohui; Dumy, Pascal; Favrot, Marie; Boturyn, Didier; Coll, Jean-Luc

    2005-04-01

    Going along with instrumental development for small animal fluorescence in vivo imaging, we are developing molecular fluorescent probes, especially for tumor targeting. Several criteria have to be taken into account for the optimization of the luminescent label. It should be adapted to the in vivo imaging optical conditions : red-shifted absorption and emission, limited overlap between absorption and emission for a good signal filtering, optimized luminescence quantum yield, limited photo-bleaching. Moreover, the whole probe should fulfill the biological requirements for in vivo labeling : adapted blood-time circulation, biological conditions compatibility, low toxicity. We here demonstrate the ability of the imaging fluorescence set-up developed in LETI to image the bio-distribution of molecular probes on short times after injection. Targeting with Cy5 labeled holo-transferrin of subcutaneous TS/Apc (angiogenic murine breast carcinoma model) or IGROV1 (human ovarian cancer) tumors was achieved. Differences in the kinetics of the protein uptake by the tumors were evidenced. IGROV1 internal metastatic nodes implanted in the peritoneal cavity could be detected in nude mice. However, targeted metastatic nodes in lung cancer could only be imaged after dissection of the mouse. These results validate our fluorescence imaging set-up and the use of Cy5 as a luminescent label. New fluorescent probes based on this dye and a molecular delivery template (the RAFT molecule) can thus be envisioned.

  6. Ion beam induced luminescence of materials

    CERN Document Server

    Brooks, R

    2001-01-01

    luminescence dead zone at the domain walls. Neodymium-yttrium-aluminium garnet (Nd:YAG) was examined and the spectra measured as a function of temperature to show the evolution of intensity of the narrow line emission from the Nd rare earth. Shifts and changes in the intrinsic UV band in the YAG material were also apparent. Thin films of alumina grown on silica on a silicon substrate, along with some that contained copper nanoclusters were also examined. TRIM software was used to model the rate of excitation within the different layers of the material for the various implant energies and to identify the source of the luminescence profile observed in each case. Evidence of thin film interference fringes was apparent in the spectra by fringe patterns modulated onto the luminescence signal as a function of wavelength and film thickness. Analysis of an alkali feldspar material using IBL, and combined with work done using RL and CL experiments, showed a shift towards lower wavelengths of the main red/IR band with ...

  7. Economic and cultural correlates of subjective wellbeing in countries using data from the Organisation for Economic Co-Operation and Development (OECD).

    Science.gov (United States)

    Gaygisiz, Esma

    2010-06-01

    The correlations among indicators of objective well-being, cultural dimensions, and subjective well-being were investigated using Organisation for Economic Co-operation and Development (OECD) data from 35 countries. The subjective well-being measures included life satisfaction as well as six positive and six negative indexes of experience. Positive and negative experience scores were subjected to principal component analysis, and two positive experience components (labeled as "positive experiences" and "time management") and two negative experience components (labeled as "pain, worry, and sadness" and "anger and boredom") were extracted. Objective well-being included economic indicators, education, and health. The cultural variables included Hofstede's and Schwartz's cultural dimensions, national Big Five personality scores, and national IQs. High life satisfaction was positively related to Gross Domestic Product, life expectancy, education, individualism, affective and intellectual autonomy, egalitarianism, and conscientiousness, whereas low life satisfaction was related to unemployment, unequal income distribution, power distance, masculinity uncertainty avoidance, embeddedness, hierarchy, and neuroticism.

  8. FBH1 co-operates with MUS81 in inducing DNA double-strand breaks and cell death following replication stress

    DEFF Research Database (Denmark)

    Fugger, Kasper; Chu, Wai Kit; Haahr, Peter

    2013-01-01

    The molecular events occurring following the disruption of DNA replication forks are poorly characterized, despite extensive use of replication inhibitors such as hydroxyurea in the treatment of malignancies. Here, we identify a key role for the FBH1 helicase in mediating DNA double-strand break...... formation following replication inhibition. We show that FBH1-deficient cells are resistant to killing by hydroxyurea, and exhibit impaired activation of the pro-apoptotic factor p53, consistent with decreased DNA double-strand break formation. Similar findings were obtained in murine ES cells carrying...... disrupted alleles of Fbh1. We also show that FBH1 through its helicase activity co-operates with the MUS81 nuclease in promoting the endonucleolytic DNA cleavage following prolonged replication stress. Accordingly, MUS81 and EME1-depleted cells show increased resistance to the cytotoxic effects...

  9. Task 9: deployment of photovoltaic technologies: co-operation with developing countries. Sources of financing for PV-based rural electrification in developing countries

    Energy Technology Data Exchange (ETDEWEB)

    Parker, W. [Institute for Sustainable Power, Highlands Ranch, CO (United States); Syngellakis, K. [IT Power Ltd, The Manor house, Chineham (United Kingdom); Shanker, A. [Innovation Energie Developpement, IED, Francheville (France)

    2004-05-15

    This report for the International Energy Agency (IEA) made by Task 9 of the Photovoltaic Power Systems (PVPS) programme takes a look at how PV-based rural electrification in developing countries can be financed. The objective of Task 9 is to increase the overall rate of successful deployment of PV systems in developing countries through increased co-operation and information exchange. This document provides an introduction to PV project financing, including funding sources available, strategies and planning needed to secure the necessary financial resources for the deployment of PV technologies in developing and transitional economies. Topics discussed include risk analysis and the barriers to financing, sources of financing, considerations and variables that influence financing decisions and the process for securing financing. Various forms of international and national financing are looked at, as are the factors influencing financing decisions.

  10. The co-operative performance of a hydrated salt assisted sponge like P(VDF-HFP) piezoelectric generator: an effective piezoelectric based energy harvester.

    Science.gov (United States)

    Adhikary, Prakriti; Garain, Samiran; Mandal, Dipankar

    2015-03-21

    We have prepared hydrated salt filler assisted sponge like P(VDF-HFP) micro-porous electroactive films to fabricate a high performance flexible piezoelectric generator (FPG). These FPGs deliver up to 8 V of open circuit voltage under external stress and also generate enough power to turn on at least fifteen commercial blue light emitting diodes (LEDs) instantly. Furthermore, capacitors have been successfully charged by repeated finger touches indicating the potential of the FPGs to be used as self-powered devices where different types of mechanical vibrations can be applied. The high performance of FPGs might be attributed to the co-operative contribution from the porous electret structure and electroactive nature of the P(VDF-HFP) film, as they also enhance the dielectric permittivity. This approach is simple, cost-effective, and well-suited for large-scale fabrication of high-performance FPGs.

  11. Rupture of the aorta following road traffic accidents in the United Kingdom 1992-1999. The results of the co-operative crash injury study.

    Science.gov (United States)

    Richens, D; Kotidis, K; Neale, M; Oakley, C; Fails, A

    2003-02-01

    The true incidence and survivability of blunt traumatic aortic rupture following road traffic accidents in the UK is unclear. The objective of this study was to determine the extent of blunt traumatic aortic rupture in the UK after road traffic accidents and the conditions under which it occurs. Data for the study was obtained from the Co-operative Crash Injury Study database. Road traffic accidents that happened between 1992 and 1999 and included in the Co-operative Crash Injury Study database were retrospectively investigated. A total of 8285 vehicles carrying 14,435 occupants were involved in 7067 accidents. There were 132 cases of blunt traumatic aortic rupture, of which the scene survival was 9% and the overall mortality was 98%. Twenty-one percent of all fatalities had blunt traumatic aortic rupture (130/613). Twenty-nine percent were due to frontal impacts and 44% were due to side impacts. Twelve percent of the blunt traumatic aortic rupture cases in frontal vehicle impacts were wearing seat belts and had airbag protection and 19% had no restraint mechanism. The Equivalent Test Speed of the accident vehicles, (where equivalent test speed provides an estimate of the vehicle impact severity and not an estimate of the vehicle speed at the time of the accident), ranged from 30 to 110 km/h in frontal impacts and from 15 to 82 km/h in side impacts. Blunt traumatic aortic rupture carries a high mortality and occurred in 21% of car occupant deaths in this sample of road traffic accidents. Impact scenarios varied but were most common from the side. The use of an airbag or seat belt does not eliminate risk. The injury can occur at low severity impacts particularly in side impact. Copyright 2002 Elsevier Science B.V.

  12. Frequency Up- and Down-conversions in Two-mode Cavity%两模腔中的参量上转换和下转换

    Institute of Scientific and Technical Information of China (English)

    李斌; 冯勋立; 张智明

    2011-01-01

    提出了一种通过建立双线性二次哈密顿量在量子腔中实现参量上转换和下转换的方案.通常在非线性过程中,介质本身不参与能量的净交换,但光波频率可以发生转换的作用称为参量转换作用.此方案建立在一个四能级原子同时与两经典场和两量子场相互作用的基础上,理论属于非线性光学四波混频范畴.将原子制备在合适的能级上,经典光场与相应的能级发生共振,而同时量子光场与相应的能级产生大失谐相互作用,在强相互作用区域内,原子和腔场失耦合,进而实现腔模的参量转换.根据所制备初始能级的不同以及光场激发能级的差异,分别实现了参量上转换和参量下转换.在利用参量下转换制备压缩算符后,对实验的可行性进行了讨论,并且给出了理论值.结果表明:在级联三能原子中采用一个级联双光子过程代替了原来的两个偶极禁戒跃迁间的经典驱动,可以保证高的不同频率之间的转换效率,并且用于光的量子操控和量子信息处理.%A scheme was proposed to construct bilinear and quadratic Hamiltonians for frequency up-and down-conversions in cavity quantum electrodynamics (QED).Generally,in nonlinear optics,the interaction that the energe swaps between different optic modes without atomic transition is named frequency conversion.The proposed scheme was based on the interactions of a single four-level atom simultaneously with two classical driving fields and a two-mode cavity field,which is in the domain of four-wave mixing.By initially preparing the atom in a suitable state,each pump light was resonant with its transition,and two quantum modes were large tune to the other two transition,respectively,In the strong laser regime,the atomic degrees of freedom could be decoupled from the cavity degrees of freedom and the frequency conversion could be realized for the cavity modes.Due to the different initial states and

  13. Radiation induced luminescence processes in c-BN

    DEFF Research Database (Denmark)

    Trinkler, L.; Berzina, B.; Benabdesselam, M.

    2004-01-01

    Spectral properties of cubic boron nitride have been studied using methods of photoluminescence (PL), X-ray excited luminescence (XL), thermoluminescence (TL) and optically stimulated luminescence. It is found that emission of cubic boron nitride is presented by 4 subbands, their relative yield...

  14. Electroluminescent apparatus having a structured luminescence conversion layer

    Science.gov (United States)

    Krummacher, Benjamin Claus [Sunnyvale, CA

    2008-09-02

    An apparatus such as a light source is disclosed which has an OLED device and a structured luminescence conversion layer disposed on the substrate or transparent electrode of said OLED device and on the exterior of said OLED device. The structured luminescence conversion layer contains color-changing and non-color-changing regions arranged in a particular pattern.

  15. Luminescence imaging using radionuclides: a potential application in molecular imaging

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jeong Chan [Department of Molecular Medicine, School of Medicine, Kyungpook National University, Daegu 700-422 (Korea, Republic of); Il An, Gwang [Molecular Imaging Research Center, Korea Institute of Radiological and Medical Sciences, Seoul 139-706 (Korea, Republic of); Park, Se-Il [Department of Molecular Medicine, School of Medicine, Kyungpook National University, Daegu 700-422 (Korea, Republic of); Oh, Jungmin [Korea Basic Science Institute Chuncheon Center, Gangwon-do 200-701 (Korea, Republic of); Kim, Hong Joo [Department of Physics and Energy Science, Kyungpook National University, Daegu 702-710 (Korea, Republic of); Su Ha, Yeong; Wang, Eun Kyung [Department of Molecular Medicine, School of Medicine, Kyungpook National University, Daegu 700-422 (Korea, Republic of); Min Kim, Kyeong; Kim, Jung Young [Molecular Imaging Research Center, Korea Institute of Radiological and Medical Sciences, Seoul 139-706 (Korea, Republic of); Lee, Jaetae [Department of Nuclear Medicine, School of Medicine, Kyungpook National University, Daegu 700-422 (Korea, Republic of); Welch, Michael J. [Department of Radiology, Washington University School of Medicine, St. Louis, MO 63110 (United States); Yoo, Jeongsoo, E-mail: yooj@knu.ac.k [Department of Molecular Medicine, School of Medicine, Kyungpook National University, Daegu 700-422 (Korea, Republic of)

    2011-04-15

    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 [{sup 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 {beta}{sup +}/{beta}{sup -} particles showed higher luminescence signals. NIH3T6.7 tumors were detected in both optical and nuclear imaging. The uptake of [{sup 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 {beta}{sup +} or {beta}{sup -} 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.

  16. Anomalous propagation of luminescence through bulk n-InP

    CERN Document Server

    Luryi, Serge; Subashiev, Arsen; Chen, Zhichao

    2010-01-01

    Implementation of a semiconductor as a scintillator with a lattice-matched surface photo-diode for radiation detection requires efficient luminescence collection. Low and heavily doped bulk n-InP has been studied to optimize luminescence transmission via photon recycling.

  17. Effects of Preparation on Luminescent Characterization of Porous Silicon

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Porous silicon samples are prepared by pulse electrochemical-etching and DC electrochemical-etching. The effects of different preparation methods on luminescent characterization of porous silicon are investigated. Compared with DC electrochemical-etching, pulse electrochemical-etching produces the porous silicon characterized by a more even surface, a stronger luminescence and a PL blue shift to a certain degree.

  18. Polarization-independent filters for luminescent solar concentrators

    NARCIS (Netherlands)

    De Boer, D.K.G.; Lin, C.W.; Giesbers, M.P.; Cornelissen, H.J.; Debije, M.G.; Verbunt, P.P.C.; Broer, D.J.

    2011-01-01

    The efficiency of Luminescent Solar Concentrators could be greatly enhanced by the use of wavelength-selective filters, since they reduce the amount of luminescent light lost. To accomplish this, polarization-independent filters have been made by combining layers of cholesteric liquid crystals,

  19. Luminescent Processes Elucidated by Simple Experiments on ZnS.

    Science.gov (United States)

    Schwankner, R.; And Others

    1981-01-01

    Describes some impurity-related optical properties of semiconductors, with special emphasis on the luminescence of zinc sulfide (ZnS). Presents and interprets five experiments using a ZnS screen, ultraviolet lamp, transparent Dewar liquid nitrogen, and a helium/neon gas base. Includes application of luminescence measurements to archaeology. (SK)

  20. Ultrashort pulse laser microsurgery system with plasma luminescence feedback control

    Energy Technology Data Exchange (ETDEWEB)

    Kim, B.M.; Feit, M.D.; Rubenchik, A.M.; Gold, D.M.; Darrow, C.B.; Da Silva, L.B.

    1997-11-10

    Plasma luminescence spectroscopy was used for precise ablation of bone tissue during ultrashort pulse laser (USPL) micro-spinal surgery. Strong contrast of the luminescence spectra between bone marrow and spinal cord provided the real time feedback control so that only bone tissue can be selectively ablated while preserving the spinal cord.

  1. Photostimulated luminescence properties of Eu2+ -doped barium aluminate phosphor.

    Science.gov (United States)

    He, Quanlong; Qiu, Guangyu; Xu, Xuhui; Qiu, Jianbei; Yu, Xue

    2015-03-01

    An intense green photostimulated luminescence in BaAl2 O4 :Eu(2+) phosphor was prepared. The thermoluminescence results indicate that there are at least three types of traps (T1 , T2 , T3 ) with different trap depths in BaAl2 O4 :Eu(2+) phosphor according to the bands located at 327, 361 and 555 K, respectively, which are closely associated with the phosphor's long persistent luminescence and photostimulated luminescence properties. In addition, as a novel optical read-out form, a photostimulated persistent luminescence signal can be repeatedly obtained in BaAl2 O4 :Eu(2+) phosphor. This shows that re-trapping of the electron released from a deep trap plays an important role in photostimulated persistent luminescence.

  2. On the relationship between luminescence excitation spectra and feldspar mineralogy

    DEFF Research Database (Denmark)

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

    1996-01-01

    Feldspar minerals can be used as naturally occurring radiation dosemeters, with dose assessment commonly using luminescence techniques. Since many feldspars contain radioactive K-40, knowledge of the mineralogy of the luminescent samples being measured is of high importance. Most feldspars contain...... more than trace amounts of highly luminescent Fe3+ impurities, and this article examines the relationship between features of the luminescence excitation spectrum of this ion with sample mineralogy. It is demonstrated that there is a near linear correspondence between the plagioclase feldspar...... groups. The results are compared with properties of the excitation spectra dose-dependent optically stimulated luminescence (OSL) in order to compare the chemical environment of the OSL donor defect, and the isolated Fe3+ centres....

  3. Visible luminescence of dysprosium ions in oxyhalide lead borate glasses

    Science.gov (United States)

    Pisarska, Joanna; Żur, Lidia; Pisarski, Wojciech A.

    2011-08-01

    Visible luminescence of Dy 3+ ions in oxyhalide lead borate glasses was examined. Luminescence spectra show two intense bands at 480 nm and 573 nm due to 4F 9/2 → 6H 15/2 (blue) and 4F 9/2 → 6H 13/2 (yellow) transitions of Dy 3+. Luminescence decays from 4F 9/2 state and yellow-to-blue luminescence intensity ratios (Y/B) were analysed with PbX 2 (X = F, Cl) content. An introduction of PbX 2 to the borate glass results in the increasing of 4F 9/2 lifetime and the decreasing of yellow-to-blue luminescence intensity ratio, which is due to reduction of covalency between Dy 3+ and O 2-/X - ions.

  4. Spectroscopic characteristic of conical bubble luminescence

    Institute of Scientific and Technical Information of China (English)

    Chen Qi-Dai; Fu Li-Min; Ai Xi-Cheng; Zhang Jian-Ping; Wang Long

    2005-01-01

    The conical bubble sonoluminescence (CBSL) from the collapse of the bubble was observed in an improved Utube apparatus. The emitted light energy of a single CBSL flash was measured to be ~ 1.4mJ. The pulse width was about 100μs. The spectra of luminescence were continuum superimposed with the spectral bands from the excitedstate C2, CN and CH. The CBSL provides a link between the light emission of the single-bubble and the multi-bubble sonoluminescence (SBSL and MBSL).

  5. 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

    2013-05-01

    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 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.

  6. Polyethylene terephthalate thin films; a luminescence study

    Science.gov (United States)

    Carmona-Téllez, S.; Alarcón-Flores, G.; Meza-Rocha, A.; Zaleta-Alejandre, E.; Aguilar-Futis, M.; Murrieta S, H.; Falcony, C.

    2015-04-01

    Polyethylene Terephthalate (PET) films doped with Rare Earths (RE3+) have been deposited on glass by spray pyrolysis technique at 240 °C, using recycled PET and (RE3+) chlorides as precursors. Cerium, terbium, dysprosium and europium were used as dopants materials, these dopants normally produce luminescent emissions at 450, 545, 573 and 612 nm respectively; the doped films also have light emissions at blue, green, yellow and red respectively. All RE3+ characteristic emissions were observed at naked eyes. Every deposited films show a high transmission in the visible range (close 80% T), films surfaces are pretty soft and homogeneous. Films thickness is around 3 μm.

  7. Near-Field Enhanced Negative Luminescent Refrigeration

    Science.gov (United States)

    Chen, Kaifeng; Santhanam, Parthiban; Fan, Shanhui

    2016-08-01

    We consider a near-field enhanced negative luminescent refrigeration system made of a polar material supporting surface-phonon polariton resonances and a narrow-band-gap semiconductor under a reverse bias. We show that in the near-field regime, such a device yields significant cooling power density and a high efficiency close to the Carnot limit. In addition, the performance of our system still persists even in the presence of strong nonidealities such as Auger recombination and sub-band-gap thermal radiation from free carriers.

  8. Eu(2+) luminescence in strontium aluminates.

    Science.gov (United States)

    Dutczak, D; Jüstel, T; Ronda, C; Meijerink, A

    2015-06-21

    The luminescence properties of Eu(2+) doped strontium aluminates are reported and reviewed for a variety of aluminates, viz. SrAl12O19, SrAl4O7, Sr4Al14O25, SrAl2O4 and Sr3Al2O6. The aim of the research is to investigate the role of local coordination and covalency of the aluminate host lattice, related to the Sr/Al ratio, on the optical properties of the Eu(2+) ion. The UV and VUV excited luminescence spectra as well as luminescence decay curves were recorded to characterize the luminescence properties of the investigated aluminates. The emission of Eu(2+) ions varies over a wide spectral range, from ultraviolet (UV) to red, for the series of aluminates. The variation in emission color can be related to the crystal-field splitting of the 5d levels and the covalent interaction with the surrounding oxygen anions. In the least covalent material, viz. SrAl12O19:Eu(2+), narrow line emission due to the (6)P7/2-(8)S7/2 transition occurs at 4 K, indicating that the 4f(6)5d excited state is situated above the (6)P7/2(4f(7)) excited state around 360 nm. The most alkaline material, viz. Sr3Al2O6:Eu(2+) is the most covalent host and exhibits several d-f emission bands in the yellow to red spectral range due to the Eu(2+) ions located on different crystallographic Sr(2+) sites. The Eu(2+) emission spectra in the other aluminates confirm the trend that with increasing Sr/Al ratio the Eu(2+) emission shifts to longer wavelengths. Interesting differences are observed for the Eu(2+) from different crystallographic sites which cannot always be related with apparent differences in the first oxygen coordination sphere. The discussion gives insight into how in a similar class of materials, strontium aluminates, the emission color of Eu(2+) can be tuned over a wide spectral region.

  9. Chemically engineered persistent luminescence nanoprobes for bioimaging

    Science.gov (United States)

    Lécuyer, Thomas; Teston, Eliott; Ramirez-Garcia, Gonzalo; Maldiney, Thomas; Viana, Bruno; Seguin, Johanne; Mignet, Nathalie; Scherman, Daniel; Richard, Cyrille

    2016-01-01

    Imaging nanoprobes are a group of nanosized agents developed for providing improved contrast for bioimaging. Among various imaging probes, optical sensors capable of following biological events or progresses at the cellular and molecular levels are actually actively developed for early detection, accurate diagnosis, and monitoring of the treatment of diseases. The optical activities of nanoprobes can be tuned on demand by chemists by engineering their composition, size and surface nature. This review will focus on researches devoted to the conception of nanoprobes with particular optical properties, called persistent luminescence, and their use as new powerful bioimaging agents in preclinical assays. PMID:27877248

  10. 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.

  11. Ion beam luminescence of Nd:YAG

    Energy Technology Data Exchange (ETDEWEB)

    Khanlary, M. [Science and Technology, Pevensey Building, University of Sussex, Brighton BN1 9QH (United Kingdom); Department of Physics, Imam Khomeini International University, Qazvin, Iran (Iran, Islamic Republic of); Hole, D.E. [Science and Technology, Pevensey Building, University of Sussex, Brighton BN1 9QH (United Kingdom); Townsend, P.D. [Science and Technology, Pevensey Building, University of Sussex, Brighton BN1 9QH (United Kingdom)]. E-mail: p.d.townsend@sussex.ac.uk

    2005-01-01

    Luminescence recorded during ion beam implantation of Nd:YAG has proved valuable in sensing structural and local crystal field changes caused by waveguide fabrication in this laser material. The relative line intensities from Nd are sensitive to excitation rate and so the spectra differ strongly between H{sup +} and H2+ excitation, with further changes in the examples using He{sup +} and N{sup +} ions. The overall intensities are reduced at lower temperatures, as well as showing variations in relative line patterns. Some suggestions of component lines and weak broad bands are offered in terms of trace rare earth and other impurities.

  12. Optically Stimulated Luminescence Fundamentals and Applications

    CERN Document Server

    McKeever, Stephen

    2011-01-01

    The book discusses advanced modern applications of optically stimulated luminescence including the appropriate fundamentals of the process. It features major chapters on the use of OSL in space radiation dosimetry, medical physics, personnel dosimetry, security, solid-state physics and other related applications. In each case, the underlying theory is discussed on an as-needed basis for a complete understanding of the phenomena, but with an emphasis of the practical applications of the technique. After an introductory chapter, Chapters 2 to 6 cover basic theory and practical aspects, personal

  13. Research Update: Luminescence in lead halide perovskites

    Science.gov (United States)

    Srimath Kandada, Ajay Ram; Petrozza, Annamaria

    2016-09-01

    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.

  14. 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

  15. International Economic Co-operation

    NARCIS (Netherlands)

    J. Tinbergen (Jan)

    1945-01-01

    textabstractSeries ‘Elseviers Economische Bibliotheek’, No.4, Elsevier, Amsterdam, 1945, 208 p. In Spanish: La Cooperación Económica Internacional, Biblioteca de la Ciencia Económica, Madrid, 1952, 186 p. 2nd, complete revised edition, 1954, Elsevier, 191 p.

  16. Luminescent DNA- and agar-based membranes.

    Science.gov (United States)

    Leones, R; Fernandes, M; Ferreira, R A S; Cesarino, I; Lima, J F; Carlos, L D; Bermudez, V de Zea; Magon, C J; Donoso, J P; Silva, M M; Pawlicka, A

    2014-09-01

    Luminescent materials containing europium ions are investigated for different optical applications. They can be obtained using bio-macromolecules, which are promising alternatives to synthetic polymers based on the decreasing oil resources. This paper describes studies of the DNA- and Agar-europium triflate luminescent membranes and its potential technological applications are expanded to electroluminescent devices. Polarized optical microscopy demonstrated that the samples are birefringent with submicrometer anisotropy. The X-ray diffraction analysis revealed predominantly amorphous nature of the samples and the atomic force microscopy images showed a roughness of the membranes of 409.0 and 136.1 nm for the samples of DNA10Eu and Agar1.11Eu, respectively. The electron paramagnetic resonance spectra of the DNA(n)Eu membranes with the principal lines at g ≈ 2.0 and g ≈ 4.8 confirmed uniform distribution of rare earth ions in a disordered matrix. Moreover, these strong and narrow resonance lines for the samples of DNA(n)Eu when compared to the Agar(n)Eu suggested a presence of paramagnetic radicals arising from the DNA matrix. The emission spectra suggested that the Eu3+ ions occupy a single local environment in both matrices and the excitation spectra monitored around the Eu emission lines pointed out that the Eu3+ ions in the Agar host were mainly excited via the broad band component rather than by direct intra-4f(6) excitation, whereas the opposite case occurred for the DNA-based sample.

  17. Novel luminescent nanoparticles for DNA detection

    Science.gov (United States)

    Dong, Ling; Yang, Zhihua; Zhang, Yi; Zhu, Yanyu; Wang, Lun; Wang, Leyu

    2010-05-01

    Highly luminescent LaF 3:Ce 3+/Tb 3+ nanocrystals were successfully prepared and surface functionalized via Layer-by-Layer technology. These as-prepared nanocrystals are highly resistant to photobleaching and pretty dispersible in aqueous solution. Due to the efficient luminescence quenching of the nanocrystals by nucleic acids, a facile fluorescence quenching method was developed for the detection of trace amount of nucleic acids. Under optimal conditions, the fluorescence intensity was proportional to the DNA concentration over the range of 0.60-25.0 μg mL -1 for calf thymus DNA (ct-DNA) and 0.60-30.0 μg mL -1 for herring sperm DNA (hs-DNA), respectively. The corresponding detection limit is 0.21 μg mL -1 for ct-DNA and 0.31 μg mL -1 for hs-DNA, respectively. The results indicated that the reported method is simple and rapid with wide linear range. Also, the recovery and relative standard deviation of this method are reasonable and satisfactory.

  18. Biological Activities of a Thai Luminescent Mushroom

    Directory of Open Access Journals (Sweden)

    Jiraporn BURAKORN

    2015-06-01

    Full Text Available Wild fruit bodies of luminescent mushrooms were collected from wood stumps over a period covering August to October 2011 in the Kosumpisai forest, Mahasarakham province, in the Northeast of Thailand. A study of the morphological and genetic characteristics of the luminescent mushroom suggested that it was Neonothopanus nimbi KS. The fruiting bodies and mycelium of Neonothopanus nimbi KS were assayed for their antimicrobial activities, antifungal activity, inhibitory activity against avian influenza H5N1 neuraminidase (NA, and anticancer activity, using organic solvent extracts. The results showed that only the methanol extract of mycelia was effective against Bacillus sphaericus, with the widest inhibition zone of 11.66±2.71 mm, but this was not effective against the other 3 bacteria (Pseudomonas aeruginosa, Serratia marcescens, and Escherichia coli. On the other hand, all of the fruit body extracts were inactive against all four bacteria. The ethylacetate extract of mycelia inhibited the NCI-H187 small lung cancer cell line, KB oral cavity cancer cell line, and the MCF7 breast cancer cell line, including Magnaporthe grisea and Curvularia lunata. The methanol extract of mycelia inhibited the KB oral cavity cell cancer cell line, Magnaporthe grisea, and Curvularia lunata at 96.66, 95.32 and 95.41 %, respectively. The results imply that polar extracts of mycelia are a resource of bioactive compounds, whereas extracts of fruit bodies have less inhibitory activity against cancer, phytopathogenic-fungi and H5N1 neuraminidase.

  19. Decreasing luminescence lifetime of evaporating phosphorescent droplets

    Science.gov (United States)

    van der Voort, D. D.; Dam, N. J.; Sweep, A. M.; Kunnen, R. P. J.; van Heijst, G. J. F.; Clercx, H. J. H.; van de Water, W.

    2016-12-01

    Laser-induced phosphorescence has been used extensively to study spray dynamics. It is important to understand the influence of droplet evaporation in the interpretation of such measurements, as it increases luminescence quenching. By suspending a single evaporating n-heptane droplet in an acoustic levitator, the properties of lanthanide-complex europium-thenoyltrifluoroacetone-trioctylphosphine oxide (Eu-TTA-TOPO) phosphorescence are determined through high-speed imaging. A decrease was found in the measured phosphorescence decay coefficient (780 → 200 μs) with decreasing droplet volumes (10-9 → 10-11 m3) corresponding to increasing concentrations (10-4 → 10-2 M). This decrease continues up to the point of shell-formation at supersaturated concentrations. The diminished luminescence is shown not to be attributable to triplet-triplet annihilation, quenching between excited triplet-state molecules. Instead, the pure exponential decays found in the measurements show that a non-phosphorescent quencher, such as free TTA/TOPO, can be attributable to this decay. The concentration dependence of the phosphorescence lifetime can therefore be used as a diagnostic of evaporation in sprays.

  20. Co-operation, Competition and Crowding: A Discrete Framework Linking Allee Kinetics, Nonlinear Diffusion, Shocks and Sharp-Fronted Travelling Waves

    Science.gov (United States)

    Johnston, Stuart T.; Baker, Ruth E.; McElwain, D. L. Sean; Simpson, Matthew J.

    2017-01-01

    Invasion processes are ubiquitous throughout cell biology and ecology. During invasion, individuals can become isolated from the bulk population and behave differently. We present a discrete, exclusion-based description of the birth, death and movement of individuals. The model distinguishes between individuals that are part of, or are isolated from, the bulk population by imposing different rates of birth, death and movement. This enables the simulation of various co-operative or competitive mechanisms, where there is either a positive or negative benefit associated with being part of the bulk population, respectively. The mean-field approximation of the discrete process gives rise to 22 different classes of partial differential equation, which can include Allee kinetics and nonlinear diffusion. Here we examine the ability of each class of partial differential equation to support travelling wave solutions and interpret the long time behaviour in terms of the individual-level parameters. For the first time we show that the strong Allee effect and nonlinear diffusion can result in shock-fronted travelling waves. We also demonstrate how differences in group and individual motility rates can influence the persistence of a population and provide conditions for the successful invasion of a population. PMID:28195135