First-principles calculations of the crystal structures, phase transition, and elastic properties of EuS have been carried out with the plane-wave pseudopotential density functional theory method. The calculated value...First-principles calculations of the crystal structures, phase transition, and elastic properties of EuS have been carried out with the plane-wave pseudopotential density functional theory method. The calculated values are in very good agreement with experimental data as well as some of the existing model calculations. The dependence of the elastic constants, the aggregate elastic modulus, and the elastic anisotropy on pressure have been investigated. Moreover, the variation of the Poisson's ratio, Debye temperature, and the compressional and shear elastic wave velocities with pressure have been investigated for the first time. Through the quasi-harmonic Debye model, the thermal expansions, heat capacities, Grneisen parameters and Debye temperatures dependence on the temperature and pressure are obtained in the pressure range from 0 GPa to 60 GPa and temperature range from 0 K to 800 K.展开更多
Eu( Ⅲ ) can be utilized as an indirect electrochemical probe to investigate the interaction of bio-molecules such as DOPA and Dopamine with Ca( Ⅱ ) in vitro. The interaction of DOPA and Dopamine with Eu( Ⅲ )...Eu( Ⅲ ) can be utilized as an indirect electrochemical probe to investigate the interaction of bio-molecules such as DOPA and Dopamine with Ca( Ⅱ ) in vitro. The interaction of DOPA and Dopamine with Eu( Ⅲ )-Eu( Ⅱ ) redox pair was investigated by electrochemical techniques. Both the neurotransmitters are structurally related and undergo interaction with Eu (Ⅲ ). Eu ( Ⅲ ) coordinates with DOPA and Dopamine through five-member chelate tings via carboxylic oxygen and amino nitrogen. The electrode kinetic parameters viz, transfer coefficient (αna), diffusion coefficient (D), forward heterogeneous rate constant ( k^0 fh) were evaluated for Eu( Ⅲ )-DOPA/Eu( Ⅲ )-Dopamine. The results obtained were used to investigate the nature of interaction of Eu (Ⅲ) with muhi-donor biomolecules. The possible mechanism was also proposed.展开更多
To explore the kinetic adsorption under continuous and nonequilibrium states, an integration of continuous measurement and adsorption platform kinetics method was proposed, which was initially called the ICM-AP kineti...To explore the kinetic adsorption under continuous and nonequilibrium states, an integration of continuous measurement and adsorption platform kinetics method was proposed, which was initially called the ICM-AP kinetics method, and a corresponding kinetic adsorption experimental method was developed. Adsorption experiments of europium(Eu) on Ca-bentonite,Na-bentonite, and the D231 cation exchange resin were performed using the ICM-AP kinetics method and continuous measurements. Because the kinetic experimental results observed in this study were different from those of traditional batch adsorption data, pseudo-first-order or pseudo-second-order kinetic models were unsuitable for fitting the experimental data.Hence, a liquid membrane diffusion(LMD) model was developed based on the assumption of simultaneous adsorption/desorption to discuss the mechanism of kinetic adsorption. The kinetic adsorption mechanism was also studied by using XPS.The results indicated that the proposed adsorption model can fit the experimental data more suitably, and the adsorption/desorption behaviors of Eu on bentonite and the D231 resin were simultaneously observed, suggesting that the adsorption kinetics of Eu(Ⅲ) was mainly dominated by hydrated Eu(Ⅲ) ions on the liquid membrane.展开更多
Nanocrystalline Gd3Ga5O12:Eu3+ with cubic phase was prepared by a urea homogeneous precipitation method. X-ray diffraction (XRD), field emission scanning electron microscopy (SEM), Fourier transform infrared spectrosc...Nanocrystalline Gd3Ga5O12:Eu3+ with cubic phase was prepared by a urea homogeneous precipitation method. X-ray diffraction (XRD), field emission scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), thermo-gravimetric and differential thermal analysis (TG-DTA) and photoluminescence spectra were used to characterize the samples. The effects of the initial solution pH value and urea content on the structure of the sample were studied. The XRD results show that pure phase Gd3Ga5O12 can be obtained at pH =6 and pH =8 of the initial solution. The average crystallite size can be calculated as in the range of 24~33 nm. The average crystallite size decreases with increasing molar ratio of urea to metal ion. The results of excitation spectra and emission spectra show that the emission peaks are ascribed to 5D0→7FJ transitions of Eu3+, and the magnetic dipole transition originated from 5D0 →7F1 of Eu3+ is the strongest; the broad excitation bands belong to change transfer band of Eu?O and the host absorption of Gd3Ga5O12. An efficient energy transfer occurs from Gd3+ to Eu3+.展开更多
Y2O3:Eu3+ phosphors were synthesized by the surface diffusion method (SDM). X-ray diffractometry (XRD), scanning electron microscopy (SEM), and energy dispersive spectrometry (EDS) were used to characterize the struct...Y2O3:Eu3+ phosphors were synthesized by the surface diffusion method (SDM). X-ray diffractometry (XRD), scanning electron microscopy (SEM), and energy dispersive spectrometry (EDS) were used to characterize the structure, morphology and component of Y2O3:Eu3+ phosphors. The photoluminescent (PL) properties were also investigated. The results reveal that the PL intensity of Y2O3:Eu3+ phosphors prepared by the surface diffusion method (SDM) is much higher than that prepared by homogeneous co-precipitation. The luminescence efficiency of the sample (Y0.997, Eu0.003)2O3 prepared by the SDM is almost 1.9 times that by homogeneous co-precipitation. The concentration of Eu3+ in the phosphor Y2O3:Eu3+ prepared by the surface diffusion can be reduced greatly owing to the activator, Eu3+ ions, distributing mainly in the outer layer of the phosphors where the photon generation process occurs.展开更多
As a data protection legislation with the dual objectives of market regulation and government supervision,the EU General Data Protection Regulation(GDPR)is designed to promote the cultivation of a market for data ele⁃...As a data protection legislation with the dual objectives of market regulation and government supervision,the EU General Data Protection Regulation(GDPR)is designed to promote the cultivation of a market for data ele⁃ments and to regulate the data processing subjects'behaviour.The civil legal norms to participate in the data market regulation are introduced,and a right-protected mode with the obligation norms of data controllers as the core is started by GDPR.However,from the perspective of GDPR's global enforcement effectiveness,as an export-orientated global standard and protection framework,the power regulation model of the EU's single digital market is facing the in⁃novative incentives of data market expansion and the tension of human rights protection.A more modest and moderate data governance regulation model has been opened by a new round of the EU digital market regulation.The legal sce⁃narios transition and digital platforms regulation more fit the regulatory demand and development goals of global digital economy development.The EU's determination to enhance the global digital market share and competitiveness is dem⁃onstrated.For China,the impact and security risks of the new round should be evaluated carefully,drawing on the ex⁃perience of the technical standpoint and institutional framework and regulatory rules of the EU digital market regula⁃tion,providing the regulatory models and Chinese solutions to respond to the EU digital market regulation,and enhanc⁃ing Chinese institutional discourse and rule-making leadership in the global digital economy.展开更多
(Gd,Lu)_(2)O_(3)∶Eu scintillation ceramics have promising applications in the high-energy X-ray imaging.Eu0.1Gd0.6Lu1.3O3 nano-powders with pure phase were prepared from the precursor calcined at 1050℃for 4 h by the...(Gd,Lu)_(2)O_(3)∶Eu scintillation ceramics have promising applications in the high-energy X-ray imaging.Eu0.1Gd0.6Lu1.3O3 nano-powders with pure phase were prepared from the precursor calcined at 1050℃for 4 h by the co-precipitation method.Using the synthesized nano-powders as initial material,Eu_(0.1)Gd_(0.6)Lu_(1.3)O_(3)ceramics were fabri-cated by vacuum pre-sintering at different temperatures for 2 h and hot isostatic pressing(HIP)at 1750℃for 3 h in ar-gon.The influence of pre-sintering temperature on the microstructure,optical and luminescence properties was investi-gated.The Eu_(0.1)Gd_(0.6)Lu_(1.3)O_(3)ceramics pre-sintered at 1625℃for 2 h combined with HIP post-treatment show the high-est in-line transmittance of 75.2%at 611 nm.The photoluminescence(PL)and X-ray excited luminescence(XEL)spectra of the Eu_(0.1)Gd_(0.6)Lu_(1.3)O_(3)transparent ceramics demonstrate a strong red emission peak at 611 nm due to the^(5)D_(0)→^(7)F_(2) transition of Eu^(3+).The PL,PLE and XEL intensities of the HIP post-treated Eu_(0.1)Gd_(0.6)Lu_(1.3)O_(3)ceramics show a trend of first ascending and then descending with the increase of pre-sintering temperature.The thermally stimulated lumines-cence(TSL)curve of the HIP post-treated Eu_(0.1)Gd_(0.6)Lu_(1.3)O_(3)ceramics presents one high peak at 178 K and two peaks with lower intensities at 253 K and 320 K.The peak at 320 K may be related to oxygen vacancies,and the lumines-cence peak at 178 K is related to defects caused by the valence state changes of Eu^(3+)ions.展开更多
A type of red luminescent Sr3Al2O6:Eu2+, Dy3+ phosphor powder is synthesised by sol-gel-combustion processing, with metal nitrates used as the source of metal ions and citric acid as a chelating agent of metal ions...A type of red luminescent Sr3Al2O6:Eu2+, Dy3+ phosphor powder is synthesised by sol-gel-combustion processing, with metal nitrates used as the source of metal ions and citric acid as a chelating agent of metal ions. By tracing the formation process of the sol-gel, it is found that it is necessary to reduce the amount of NO3 by dropping ethanol into the solution for forming a stable and homogeneous sol-gel. Thermogravimetric and Differential Scanning Calorimeter Analysis, x-ray diffractionmeter, scanning electron microscopy and photoluminescence spectroscopy are used to investigate the luminescent properties of the as-synthesised Sr3A1206:Eu2+, Dy3+. The results reveal that the Sr3Al2O6 crystallises completely when the combustion ash is sintered at 1250℃. The excitation and the emission spectra indicate that the excitation broadband lies mainly in a visible range and the phosphors emit a strong light at 618 nm under the excitation of 472 nm. The afterglow of (Sr0.94Eu0.03Dy0.03)3Al2O6 phosphors sintered at 1250℃ lasts for over 1000 s when the excited source is cut off.展开更多
Agriculture is a basic industry related to national economy and people’s livelihood,and is also the cornerstone of national economic development. European Union(EU) is the second largest exporter of agricultural prod...Agriculture is a basic industry related to national economy and people’s livelihood,and is also the cornerstone of national economic development. European Union(EU) is the second largest exporter of agricultural products in the world,and its agricultural production change has international influence. In this paper,starting from two angles of EU agricultural development scale and target,development stage of its agricultural production is explored,and development and evolution causes of EU agriculture are analyzed: efficiency and benefit targets cause change of EU agricultural management model; change of agricultural product supply-demand pattern leads the evolution of EU agricultural development idea; the reflection of agricultural development target impels the transformation of EU agricultural development. On this basis,the below conclusions are obtained: agricultural development could evolve according to the changes of economic and social conditions; it is a necessary requirement of promoting internal market stability and international market harmony to actively use agricultural support policies adapting to agricultural development at each stage; it is an important measurement of impelling agricultural modernization process to promote innovation of agricultural management model and development of market integration; it is an inevitable road of realizing sustainable development of agriculture to develop ecological agriculture and emphasize equal development of agriculture and countryside. On this basis,it could provide the reference for agricultural development of China based on EU agricultural development experience.展开更多
γ-LiAlO2:Eu3+(Eu3+:LAO) phosphor was obtained by gel combustion method using LiNO3,Al(NO3)3·9H2O,Eu(NO3)3·6H2O and citric acid as raw materials.The structure,morphology and luminescence were chara...γ-LiAlO2:Eu3+(Eu3+:LAO) phosphor was obtained by gel combustion method using LiNO3,Al(NO3)3·9H2O,Eu(NO3)3·6H2O and citric acid as raw materials.The structure,morphology and luminescence were characterized by means of X-ray diffraction (XRD),scanning electron microscopy (SEM),photoluminescence (PL).The results demonstrated that the phosphor was pure-phase of flaky tetragonal crystal system with a mean size of around 1 μm.The strongest excitation peak was at 254 nm,belonging to the broadband excitation and the maximum emission peak was at 613 nm,corresponding to the 5D0→7F2 transition of Eu3+.Luminous intensity is closely related to the calcination temperature and doping concentration of Eu3+.展开更多
The establishment and rapid rise of the European Union (EU) have increasingly made Europe an independent force. Objectively, the enlargement of both the EU and NATO has speeded up the process of European integration, ...The establishment and rapid rise of the European Union (EU) have increasingly made Europe an independent force. Objectively, the enlargement of both the EU and NATO has speeded up the process of European integration, and "One important link of Russia’s diplomacy展开更多
SrAl 2O 4∶Eu was adopted as main phase to prepare the ceramic pumping cavity material with ultraviolet(UV) converting function in order to match with laser absorption spectra. The relationship between SrAl 2O 4∶...SrAl 2O 4∶Eu was adopted as main phase to prepare the ceramic pumping cavity material with ultraviolet(UV) converting function in order to match with laser absorption spectra. The relationship between SrAl 2O 4∶Eu powder processing and fluorescence effect was studied. The glass material with lower refractive index was added to the SrAl 2O 4∶Eu based ceramics. The diffusive reflectivity and the influence of fluorescence effect on reflection spectra of the ceramics were investigated. Some experimental results can be used for evaluating technical feasibility of the SrAl 2O 4∶Eu based ceramics used for laser reflectors.展开更多
Long-lasting SrAl2O4∶Eu, Dy phosphor was successfully prepared from a mesoporous precursor. The precursor was synthesized by templating method using nonionic Polyethylene Oxide (PEO) as surfactants, which was proved ...Long-lasting SrAl2O4∶Eu, Dy phosphor was successfully prepared from a mesoporous precursor. The precursor was synthesized by templating method using nonionic Polyethylene Oxide (PEO) as surfactants, which was proved by TG-DTG, X-Ray Diffraction (XRD) and Transmission Electron Microscopy (TEM) analysis. The analysis results indicated that regular cylindrical-to-hexagonal shaped pores with several nanometers were obtained. The structure and morphology of the SrAl2O4∶Eu, Dy phosphor by templating method was characterized by XRD and Scanning Electron Microscopy (SEM). The XRD results showed that a pure SrAl2O4 phase formed at 900 ℃ by templating method. The SEM morphologies of the obtained phosphors prepared by templating synthesis were uniform and porous multicrystalline with average diameter size of 5 μm. The broad-band UV-excited SrAl2O4∶Eu, Dy phosphor derived from a mosoporous precursor was observed at λmax=515 nm due to the transitions from the 4f65d1 to the 4f7 configurations of Eu2+ ion. The main excitation and emission intensity of the phosphor with this method were stronger than that obtained by solid state reaction method. And the obtained long-lasting phosphor with this method revealed a better afterglow compared to the phosphor prepared through solid state reaction method.展开更多
If managed properly, the shipbuilding industry could have a high multiplication effect. This is why it is often considered as the key industry in economic development in many national economies, especially those in tr...If managed properly, the shipbuilding industry could have a high multiplication effect. This is why it is often considered as the key industry in economic development in many national economies, especially those in transition. The three major players in the global shipbuilding industry are South Korea, China and Japan. Europe is positioned forth, but its market share is decreasing rapidly. This is also the case with the Croatian shipbuilding industry. This paper aims to critique the level of adaptability of Croatian shipyards to the rapidly changing environment of global industry. It also relates the question of survival and sustainable development of Croatian shipbuilding and strategic positioning of European shipbuilders. The results of this research had shown that without clusterizing the shipbuilding industry at EU integration level, and not at national levels, Europe will soon loose the struggle for market position improvement or even maintenance to the far more organized Asian rivals. Findings regarding the Croatian shipbuilding industry indicate the absence of a viable strategy on the national level. Furthermore, the paper tries to prove that success will be based on the possibility and will of Croatian shipbuilders to form strong collaborations mad business networks with subcontractors and other institutions. This should not be limited only at national level, but should incorporate different kinds of EU shipbuilding consortiums and clusters as well as other forms of strategic alliances.展开更多
Since George W. Bush assumed the presidency in early 2001, a tense situation had occurred in the relationships among world big powers. In the aftermath of September 11,significant improvement has been made in Sino-U.S...Since George W. Bush assumed the presidency in early 2001, a tense situation had occurred in the relationships among world big powers. In the aftermath of September 11,significant improvement has been made in Sino-U.S. and Russia-U. S. relations. In the meantime, corresponding changes have taken place in EU-U. S.and Russia-China relations.展开更多
The aim of the article is to analyze the challenges of developing business in Poland in old and new EU policy fields For the last two decades, Polish policy of business operations has been implemented at a national le...The aim of the article is to analyze the challenges of developing business in Poland in old and new EU policy fields For the last two decades, Polish policy of business operations has been implemented at a national level largely on the basis of the aims pursued by the European Union, which influence the modernization of the state in regards to economic progress, infrastructure development and technological advancement. Such provisions were included, for instance, in the new and last cohesion policy prospect for the period of 2014-2020. One of the goals of this article is to present a model of functioning and development of business in Poland, taking into account the strategies of the European Union in the period 2014-2020. In this article I made attempts to answer the following questions: What is the level of impact exerted upon Polish business by new policies introduced by the EU? Is the introduction of new EU policies significant for the development of business in Poland? Or does it cause its partial destruction that impedes the development of companies, especially small- and medium-sized enterprises, which significantly contribute to the increase and development of GDP in Poland and in most member states of the EU? Is the functioning of business in Poland dependent on new EU policies and new legal regulations introduced by decision-makers at the national level?展开更多
Land property in the post socialist countries was rebuilt in the beginning of the 1990s. The process went in different way in all of the post-socialist countries. The result of the privatization of agricultural land w...Land property in the post socialist countries was rebuilt in the beginning of the 1990s. The process went in different way in all of the post-socialist countries. The result of the privatization of agricultural land was a fragmented, direct or indirect smallholder ownership structure in most of the new member states of the EU. The land, partly or totally was given back to the owners and inheritors of land reforms following the war. It means that considerable proportion of the land is cultivated by tenants, the fragmented estate structure decreases the efficiency and the increasing rental fees further destroy the profitability and competitiveness of farming. Regarding to the competitiveness of agriculture, Poland showed a developing tendency after the accession, but Hungary suffers from serious problems. Applying descriptive statistics between the changes of land use and land ownership during the research relation analysis, emphasizing the effect in competitiveness of the land price and a land rent, the paper tries to identify the main differences and similarities in land use and property structure, and their effects on the agricultural competitiveness based on the FADN data base, since 2004-2007.展开更多
In the past three years from 2015 through 2017, Europe has been confronted by the multiple challenges of terror attacks, Greek debt crisis, strains caused by a massive influx of migrants, Brexit and the America First ...In the past three years from 2015 through 2017, Europe has been confronted by the multiple challenges of terror attacks, Greek debt crisis, strains caused by a massive influx of migrants, Brexit and the America First Policy of US President Trump. These tensions are generating strong pressures to rebuild the EU. In France, the ambitious centrist Emmanuel Macron at the age of 39, staved off the challenge of the far right Marine Le Pen to win a crushing victory in the May 2017 presidential election. Macron has been dubbed the third transformative president in the footsteps of Charles de Gaulle and Fran?ois Mitterrand. Macron afterwards laid out his vision for rebuilding the EU in a speech at the Sorbonne in Paris. In the German federal election, the CDU/CSU, led by Angela Merkel, plunged to 33% of the vote and its coalition partner the center-left SPD, suffered a historic defeat with only 22%. The xenophobic nationalist Alternative for Germany conversely rose to become the third largest party in the Bundestag with 94 seats and 12.6%. But after many twists and turns, the Macron-Merkel ship has set sail in quest of an “annus mirabilis” that will herald a new age in 2018.展开更多
基金V. ACKNOWLEDGMENTS This work was supported by the National Natural Science Foundation of China (No.40804034 and No.11304141), the Natural Science Foundation of the Education Department of Henan Province of China (No.2011B140014), the Program for the Science and Technology Department of Henan Province of China (No. 112102310641), and the Program for Innovative Research Team (in Science and Technology) in University of Henan Province (No.13IRTSTHN020).
文摘First-principles calculations of the crystal structures, phase transition, and elastic properties of EuS have been carried out with the plane-wave pseudopotential density functional theory method. The calculated values are in very good agreement with experimental data as well as some of the existing model calculations. The dependence of the elastic constants, the aggregate elastic modulus, and the elastic anisotropy on pressure have been investigated. Moreover, the variation of the Poisson's ratio, Debye temperature, and the compressional and shear elastic wave velocities with pressure have been investigated for the first time. Through the quasi-harmonic Debye model, the thermal expansions, heat capacities, Grneisen parameters and Debye temperatures dependence on the temperature and pressure are obtained in the pressure range from 0 GPa to 60 GPa and temperature range from 0 K to 800 K.
基金Foundation ite m:Project supported by DST(SP/S1/F03/98)
文摘Eu( Ⅲ ) can be utilized as an indirect electrochemical probe to investigate the interaction of bio-molecules such as DOPA and Dopamine with Ca( Ⅱ ) in vitro. The interaction of DOPA and Dopamine with Eu( Ⅲ )-Eu( Ⅱ ) redox pair was investigated by electrochemical techniques. Both the neurotransmitters are structurally related and undergo interaction with Eu (Ⅲ ). Eu ( Ⅲ ) coordinates with DOPA and Dopamine through five-member chelate tings via carboxylic oxygen and amino nitrogen. The electrode kinetic parameters viz, transfer coefficient (αna), diffusion coefficient (D), forward heterogeneous rate constant ( k^0 fh) were evaluated for Eu( Ⅲ )-DOPA/Eu( Ⅲ )-Dopamine. The results obtained were used to investigate the nature of interaction of Eu (Ⅲ) with muhi-donor biomolecules. The possible mechanism was also proposed.
基金This work was supported by the Natural Science Foundation of the Jiangxi Province,China(No.20202BABL203004)Opening Project of the State Key Laboratory of Nuclear Resources and Environment(East China University of Technology)(No.2022NRE23)Opening Project of the Jiangxi Province Key Laboratory of Polymer Micro/Nano Manufacturing and Devices(No.PMND202101).
文摘To explore the kinetic adsorption under continuous and nonequilibrium states, an integration of continuous measurement and adsorption platform kinetics method was proposed, which was initially called the ICM-AP kinetics method, and a corresponding kinetic adsorption experimental method was developed. Adsorption experiments of europium(Eu) on Ca-bentonite,Na-bentonite, and the D231 cation exchange resin were performed using the ICM-AP kinetics method and continuous measurements. Because the kinetic experimental results observed in this study were different from those of traditional batch adsorption data, pseudo-first-order or pseudo-second-order kinetic models were unsuitable for fitting the experimental data.Hence, a liquid membrane diffusion(LMD) model was developed based on the assumption of simultaneous adsorption/desorption to discuss the mechanism of kinetic adsorption. The kinetic adsorption mechanism was also studied by using XPS.The results indicated that the proposed adsorption model can fit the experimental data more suitably, and the adsorption/desorption behaviors of Eu on bentonite and the D231 resin were simultaneously observed, suggesting that the adsorption kinetics of Eu(Ⅲ) was mainly dominated by hydrated Eu(Ⅲ) ions on the liquid membrane.
基金financially supported by the Science and Technology Research Project of Department of Education of Liaoning Province,China(No.L2011063)
文摘Nanocrystalline Gd3Ga5O12:Eu3+ with cubic phase was prepared by a urea homogeneous precipitation method. X-ray diffraction (XRD), field emission scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), thermo-gravimetric and differential thermal analysis (TG-DTA) and photoluminescence spectra were used to characterize the samples. The effects of the initial solution pH value and urea content on the structure of the sample were studied. The XRD results show that pure phase Gd3Ga5O12 can be obtained at pH =6 and pH =8 of the initial solution. The average crystallite size can be calculated as in the range of 24~33 nm. The average crystallite size decreases with increasing molar ratio of urea to metal ion. The results of excitation spectra and emission spectra show that the emission peaks are ascribed to 5D0→7FJ transitions of Eu3+, and the magnetic dipole transition originated from 5D0 →7F1 of Eu3+ is the strongest; the broad excitation bands belong to change transfer band of Eu?O and the host absorption of Gd3Ga5O12. An efficient energy transfer occurs from Gd3+ to Eu3+.
基金Project(2007CB613607) supported by the National Basic Research Program of China
文摘Y2O3:Eu3+ phosphors were synthesized by the surface diffusion method (SDM). X-ray diffractometry (XRD), scanning electron microscopy (SEM), and energy dispersive spectrometry (EDS) were used to characterize the structure, morphology and component of Y2O3:Eu3+ phosphors. The photoluminescent (PL) properties were also investigated. The results reveal that the PL intensity of Y2O3:Eu3+ phosphors prepared by the surface diffusion method (SDM) is much higher than that prepared by homogeneous co-precipitation. The luminescence efficiency of the sample (Y0.997, Eu0.003)2O3 prepared by the SDM is almost 1.9 times that by homogeneous co-precipitation. The concentration of Eu3+ in the phosphor Y2O3:Eu3+ prepared by the surface diffusion can be reduced greatly owing to the activator, Eu3+ ions, distributing mainly in the outer layer of the phosphors where the photon generation process occurs.
基金The special project of Anhui Philosophy and Social Science Planning Project(AHSKXZX2021D03)。
文摘As a data protection legislation with the dual objectives of market regulation and government supervision,the EU General Data Protection Regulation(GDPR)is designed to promote the cultivation of a market for data ele⁃ments and to regulate the data processing subjects'behaviour.The civil legal norms to participate in the data market regulation are introduced,and a right-protected mode with the obligation norms of data controllers as the core is started by GDPR.However,from the perspective of GDPR's global enforcement effectiveness,as an export-orientated global standard and protection framework,the power regulation model of the EU's single digital market is facing the in⁃novative incentives of data market expansion and the tension of human rights protection.A more modest and moderate data governance regulation model has been opened by a new round of the EU digital market regulation.The legal sce⁃narios transition and digital platforms regulation more fit the regulatory demand and development goals of global digital economy development.The EU's determination to enhance the global digital market share and competitiveness is dem⁃onstrated.For China,the impact and security risks of the new round should be evaluated carefully,drawing on the ex⁃perience of the technical standpoint and institutional framework and regulatory rules of the EU digital market regula⁃tion,providing the regulatory models and Chinese solutions to respond to the EU digital market regulation,and enhanc⁃ing Chinese institutional discourse and rule-making leadership in the global digital economy.
文摘(Gd,Lu)_(2)O_(3)∶Eu scintillation ceramics have promising applications in the high-energy X-ray imaging.Eu0.1Gd0.6Lu1.3O3 nano-powders with pure phase were prepared from the precursor calcined at 1050℃for 4 h by the co-precipitation method.Using the synthesized nano-powders as initial material,Eu_(0.1)Gd_(0.6)Lu_(1.3)O_(3)ceramics were fabri-cated by vacuum pre-sintering at different temperatures for 2 h and hot isostatic pressing(HIP)at 1750℃for 3 h in ar-gon.The influence of pre-sintering temperature on the microstructure,optical and luminescence properties was investi-gated.The Eu_(0.1)Gd_(0.6)Lu_(1.3)O_(3)ceramics pre-sintered at 1625℃for 2 h combined with HIP post-treatment show the high-est in-line transmittance of 75.2%at 611 nm.The photoluminescence(PL)and X-ray excited luminescence(XEL)spectra of the Eu_(0.1)Gd_(0.6)Lu_(1.3)O_(3)transparent ceramics demonstrate a strong red emission peak at 611 nm due to the^(5)D_(0)→^(7)F_(2) transition of Eu^(3+).The PL,PLE and XEL intensities of the HIP post-treated Eu_(0.1)Gd_(0.6)Lu_(1.3)O_(3)ceramics show a trend of first ascending and then descending with the increase of pre-sintering temperature.The thermally stimulated lumines-cence(TSL)curve of the HIP post-treated Eu_(0.1)Gd_(0.6)Lu_(1.3)O_(3)ceramics presents one high peak at 178 K and two peaks with lower intensities at 253 K and 320 K.The peak at 320 K may be related to oxygen vacancies,and the lumines-cence peak at 178 K is related to defects caused by the valence state changes of Eu^(3+)ions.
基金Project supported by the Key Research Project of Science and Technology of Shanxi, Shanxi Province, China (Grant No 2007031141)the Natural Science Foundation of Shanxi Province, China (Grant No 2007011061)the Scientific Research Foundation of the Higher Education Institutions of Shanxi Province, China (Grant No 20080012)
文摘A type of red luminescent Sr3Al2O6:Eu2+, Dy3+ phosphor powder is synthesised by sol-gel-combustion processing, with metal nitrates used as the source of metal ions and citric acid as a chelating agent of metal ions. By tracing the formation process of the sol-gel, it is found that it is necessary to reduce the amount of NO3 by dropping ethanol into the solution for forming a stable and homogeneous sol-gel. Thermogravimetric and Differential Scanning Calorimeter Analysis, x-ray diffractionmeter, scanning electron microscopy and photoluminescence spectroscopy are used to investigate the luminescent properties of the as-synthesised Sr3A1206:Eu2+, Dy3+. The results reveal that the Sr3Al2O6 crystallises completely when the combustion ash is sintered at 1250℃. The excitation and the emission spectra indicate that the excitation broadband lies mainly in a visible range and the phosphors emit a strong light at 618 nm under the excitation of 472 nm. The afterglow of (Sr0.94Eu0.03Dy0.03)3Al2O6 phosphors sintered at 1250℃ lasts for over 1000 s when the excited source is cut off.
文摘Agriculture is a basic industry related to national economy and people’s livelihood,and is also the cornerstone of national economic development. European Union(EU) is the second largest exporter of agricultural products in the world,and its agricultural production change has international influence. In this paper,starting from two angles of EU agricultural development scale and target,development stage of its agricultural production is explored,and development and evolution causes of EU agriculture are analyzed: efficiency and benefit targets cause change of EU agricultural management model; change of agricultural product supply-demand pattern leads the evolution of EU agricultural development idea; the reflection of agricultural development target impels the transformation of EU agricultural development. On this basis,the below conclusions are obtained: agricultural development could evolve according to the changes of economic and social conditions; it is a necessary requirement of promoting internal market stability and international market harmony to actively use agricultural support policies adapting to agricultural development at each stage; it is an important measurement of impelling agricultural modernization process to promote innovation of agricultural management model and development of market integration; it is an inevitable road of realizing sustainable development of agriculture to develop ecological agriculture and emphasize equal development of agriculture and countryside. On this basis,it could provide the reference for agricultural development of China based on EU agricultural development experience.
基金Funded by Southwest University of Technology (No.08zx0103)
文摘γ-LiAlO2:Eu3+(Eu3+:LAO) phosphor was obtained by gel combustion method using LiNO3,Al(NO3)3·9H2O,Eu(NO3)3·6H2O and citric acid as raw materials.The structure,morphology and luminescence were characterized by means of X-ray diffraction (XRD),scanning electron microscopy (SEM),photoluminescence (PL).The results demonstrated that the phosphor was pure-phase of flaky tetragonal crystal system with a mean size of around 1 μm.The strongest excitation peak was at 254 nm,belonging to the broadband excitation and the maximum emission peak was at 613 nm,corresponding to the 5D0→7F2 transition of Eu3+.Luminous intensity is closely related to the calcination temperature and doping concentration of Eu3+.
文摘The establishment and rapid rise of the European Union (EU) have increasingly made Europe an independent force. Objectively, the enlargement of both the EU and NATO has speeded up the process of European integration, and "One important link of Russia’s diplomacy
文摘SrAl 2O 4∶Eu was adopted as main phase to prepare the ceramic pumping cavity material with ultraviolet(UV) converting function in order to match with laser absorption spectra. The relationship between SrAl 2O 4∶Eu powder processing and fluorescence effect was studied. The glass material with lower refractive index was added to the SrAl 2O 4∶Eu based ceramics. The diffusive reflectivity and the influence of fluorescence effect on reflection spectra of the ceramics were investigated. Some experimental results can be used for evaluating technical feasibility of the SrAl 2O 4∶Eu based ceramics used for laser reflectors.
基金the National Natural Science Foundation of China (20376009)
文摘Long-lasting SrAl2O4∶Eu, Dy phosphor was successfully prepared from a mesoporous precursor. The precursor was synthesized by templating method using nonionic Polyethylene Oxide (PEO) as surfactants, which was proved by TG-DTG, X-Ray Diffraction (XRD) and Transmission Electron Microscopy (TEM) analysis. The analysis results indicated that regular cylindrical-to-hexagonal shaped pores with several nanometers were obtained. The structure and morphology of the SrAl2O4∶Eu, Dy phosphor by templating method was characterized by XRD and Scanning Electron Microscopy (SEM). The XRD results showed that a pure SrAl2O4 phase formed at 900 ℃ by templating method. The SEM morphologies of the obtained phosphors prepared by templating synthesis were uniform and porous multicrystalline with average diameter size of 5 μm. The broad-band UV-excited SrAl2O4∶Eu, Dy phosphor derived from a mosoporous precursor was observed at λmax=515 nm due to the transitions from the 4f65d1 to the 4f7 configurations of Eu2+ ion. The main excitation and emission intensity of the phosphor with this method were stronger than that obtained by solid state reaction method. And the obtained long-lasting phosphor with this method revealed a better afterglow compared to the phosphor prepared through solid state reaction method.
文摘If managed properly, the shipbuilding industry could have a high multiplication effect. This is why it is often considered as the key industry in economic development in many national economies, especially those in transition. The three major players in the global shipbuilding industry are South Korea, China and Japan. Europe is positioned forth, but its market share is decreasing rapidly. This is also the case with the Croatian shipbuilding industry. This paper aims to critique the level of adaptability of Croatian shipyards to the rapidly changing environment of global industry. It also relates the question of survival and sustainable development of Croatian shipbuilding and strategic positioning of European shipbuilders. The results of this research had shown that without clusterizing the shipbuilding industry at EU integration level, and not at national levels, Europe will soon loose the struggle for market position improvement or even maintenance to the far more organized Asian rivals. Findings regarding the Croatian shipbuilding industry indicate the absence of a viable strategy on the national level. Furthermore, the paper tries to prove that success will be based on the possibility and will of Croatian shipbuilders to form strong collaborations mad business networks with subcontractors and other institutions. This should not be limited only at national level, but should incorporate different kinds of EU shipbuilding consortiums and clusters as well as other forms of strategic alliances.
文摘Since George W. Bush assumed the presidency in early 2001, a tense situation had occurred in the relationships among world big powers. In the aftermath of September 11,significant improvement has been made in Sino-U.S. and Russia-U. S. relations. In the meantime, corresponding changes have taken place in EU-U. S.and Russia-China relations.
文摘The aim of the article is to analyze the challenges of developing business in Poland in old and new EU policy fields For the last two decades, Polish policy of business operations has been implemented at a national level largely on the basis of the aims pursued by the European Union, which influence the modernization of the state in regards to economic progress, infrastructure development and technological advancement. Such provisions were included, for instance, in the new and last cohesion policy prospect for the period of 2014-2020. One of the goals of this article is to present a model of functioning and development of business in Poland, taking into account the strategies of the European Union in the period 2014-2020. In this article I made attempts to answer the following questions: What is the level of impact exerted upon Polish business by new policies introduced by the EU? Is the introduction of new EU policies significant for the development of business in Poland? Or does it cause its partial destruction that impedes the development of companies, especially small- and medium-sized enterprises, which significantly contribute to the increase and development of GDP in Poland and in most member states of the EU? Is the functioning of business in Poland dependent on new EU policies and new legal regulations introduced by decision-makers at the national level?
文摘Land property in the post socialist countries was rebuilt in the beginning of the 1990s. The process went in different way in all of the post-socialist countries. The result of the privatization of agricultural land was a fragmented, direct or indirect smallholder ownership structure in most of the new member states of the EU. The land, partly or totally was given back to the owners and inheritors of land reforms following the war. It means that considerable proportion of the land is cultivated by tenants, the fragmented estate structure decreases the efficiency and the increasing rental fees further destroy the profitability and competitiveness of farming. Regarding to the competitiveness of agriculture, Poland showed a developing tendency after the accession, but Hungary suffers from serious problems. Applying descriptive statistics between the changes of land use and land ownership during the research relation analysis, emphasizing the effect in competitiveness of the land price and a land rent, the paper tries to identify the main differences and similarities in land use and property structure, and their effects on the agricultural competitiveness based on the FADN data base, since 2004-2007.
文摘In the past three years from 2015 through 2017, Europe has been confronted by the multiple challenges of terror attacks, Greek debt crisis, strains caused by a massive influx of migrants, Brexit and the America First Policy of US President Trump. These tensions are generating strong pressures to rebuild the EU. In France, the ambitious centrist Emmanuel Macron at the age of 39, staved off the challenge of the far right Marine Le Pen to win a crushing victory in the May 2017 presidential election. Macron has been dubbed the third transformative president in the footsteps of Charles de Gaulle and Fran?ois Mitterrand. Macron afterwards laid out his vision for rebuilding the EU in a speech at the Sorbonne in Paris. In the German federal election, the CDU/CSU, led by Angela Merkel, plunged to 33% of the vote and its coalition partner the center-left SPD, suffered a historic defeat with only 22%. The xenophobic nationalist Alternative for Germany conversely rose to become the third largest party in the Bundestag with 94 seats and 12.6%. But after many twists and turns, the Macron-Merkel ship has set sail in quest of an “annus mirabilis” that will herald a new age in 2018.