Quantum cutting downconversion by cooperative energy transfer from Bi^(3+) to Yb^(3+) in Y_2O_3 phosphor

Bi3＋ and Yb3＋ codoped cubic Y2O3 phosphors are prepared by pechini sol-gel method. Strong near-infrared （NIR） emission around 980 nm from Yb3＋ （2F5/2＋2 F7/2） is observed under ultraviolet light excitation. A broad excitation band ranging from 320 to 360 nm, owing to the 6s2→6s6p transition of Bi3＋ ions, is recorded when the Yb3＋ emission is monitored, which suggests a very efficient energy transfer from Bi3＋ ions to Yb3＋ ions. The Yb3＋ concentration dependences of both the Bi3＋ and the Yb3＋ emissions are investigated. The decay curve of Bi3＋ emission under the excitation of 355 nm pulse laser is used to explore the Bi3＋ →＋Yb3＋ energy transfer process. Cooperative energy transfer （CET） is discussed as a possible mechanism for the near-infrared emission.

Cooperative energy transfer in Eu^(3+),Yb^(3+) codoped Y_2O_3 phosphor

Under 980 nm laser excitation,red emission(5D0-7FJ(J=0,1,2)) of Eu3+ was observed in cubic Y2O3 codoped with Eu3+ and Yb3+.The dependence of the upconverted emission on doping concentration and laser power was studied.Yb3+ emission around 1000 nm(2F5/2-2F7/2) was reported upon excitation of Eu3+ ions.The decay curves of 5DJ(J=0,2) emission of Eu3+ under excitation of 266 nm pulse laser were examined to investigate the Eu3+→Yb3+ energy transfer process.Cooperative energy transfer process was discussed as the...

Energy Cooperation between BRICS Countries(Ⅰ)

The economic rise of the BRICS countries(Brazil, Russia, India, China and South Africa) is closely tied to global energy politics and their increased consumption of global energy. Energy cooperation is one of the main forces behind the development of BRICS. Looking forward, energy concerns will undoubtedly remain an important influencing force for the BRICS, shaping their domestic politics and international relations. The pursuit of oil and gas(China, India, and South Africa) to support economic development and the search for stable petroleum markets(Brazil and Russia) have shaped BRICS relations with other countries and regions. This article is trying to elaborate on the reasons why BRICS Energy cooperation is beneficial for its members; also, this article regards the main challenges hindering cooperation, analyzes BRICS energy cooperation through the use of SWOT analysis and muses potential strategic points for BRICS countries up until 2050.

Research on Deepening Energy Cooperation between China and Countries along the Belt and Road

Promoting broader and deeper international energy cooperation is an important part of China’s energy development under the new development paradigm of“dual-circulation.”The proposal and practice of the Belt and Road Initiative(BRI)cooperation have encouraged closer energy cooperation between China and countries along the Belt and Road.Energy cooperation has become one of the areas with the fastest growth and the most remarkable achievements in the BRI construction,which has made an important contribution to the realization of China’s energy development with high quality under open conditions.To accelerate higher levels and more sustainable development of energy cooperation between China and the countries along the Belt and Road,it is necessary to further improve energy policy coordination mechanisms,widen the breadth and depth of energy facilities connectivity,promote unimpeded energy trade,and actively undertake innovative modes of financial support for energy cooperation as well as lay a sound social foundation for people-to-people bonds.

Speech on the Opening Ceremony of European Union-China "Energy Cooperation Industry Conference

Ladies, Gentlemen, Friends: Today, I feel greatly honoured to have opportunity to attend European Union-China《Energy Cooperation Industry Conference cosponsored by China State Science and Technology Commission and European Union of Federalists, held in Beijing. On this occasion, please allow me on behalf of the Ministry of Electric Power, People’s Republic of China, to express thanks for China State Science

INTERNATIONAL COOPERATION PROMOTES HIGH ENERGY PHYSICS' DEVELOPMENT IN CHINA——A talk at the 17th International Symposium on Lepton-Photon Interactions (LP'95)

This article first presents an overview of the Internationa] Symposium on Lepton-Photon Interactions (LP’95) and briefly introduce Chinese research achievements in the discipline. It highlights the necessity and importance of international cooperation in the HEP community of the world.

Near-infrared downconversion in Eu^(2+) and Pr^(3+) co-doped KSrPO_4 phosphor

A novel near-infrared （NIR） downconversion （DC） phosphor KSrPO4：Eu2＋, Pr3＋ is synthesized by the conventional high temperature solid-state reaction. The Eu2＋ acts as an efficient sensitizer for Pr3＋ in the KSrPO4 host. With broad- band near-ultraviolet light excitation induced by the 4f→5d transition of Eu2＋, the characteristic NIR emission of Pr3＋, peaking at 974 nm and 1019 nm due to 3po →1G4 and 1G4→3H4 transitions, is generated as a result of the energy transfer from Eu2＋ to Pr3＋. The luminescence spectra in both the visible and the NIR regions and the decay lifetime curves of Eu2＋ prove the energy transfer from Eu2＋ to Pr3＋. This Eu2＋ and Pr3＋ co-doped KSrPO4 phosphor may be a promising candidate to modify the spectral mismatch behavior of crystalline solar cells and sunlight.

Personalized real-time pricing for efficient and fair demandresponse in energy cooperatives and highly competitive flexibility markets

This paper contributes to the well-known challenge of active user participation in demand side management(DSM).In DSM, there is a need for modern pricing mechanisms that will be able to effectively incentivize selfishly behaving users in modifying their energy consumption pattern towards system-level goals like energy efficiency.Three generally desired properties of DSM algorithms are: user satisfaction, energy cost minimization and fairness.In this paper, a personalized real-time pricing(P-RTP) mechanism design framework is proposed that fairly allocates the energy cost reduction only to the users that provoke it.Thus, the proposed mechanism achieves significant reduction of the energy cost without sacrificing at all the welfare(user satisfaction)of electricity consumers.The business model that the proposed mechanism envisages is highly competitive flexibility market environments as well as energy cooperatives.

Prospect for strategic minerals exploration and development,investment environment and cooperation in Mozambique

Mozambique is an essential country in the Belt and Road Initiative,and it is also to cooperation between China and with Africa in energy resources.It is located in the critical node of the“East Africa Channel”and close to the“African Twin Ocean Railway”,which is an important strategic position.Mozambique has abundant mineral resources and vast reserves of advantageous minerals.The natural gas reserves of Mozambique ranked second in Africa.It also has world--class scale graphite and rich iron,gold,copper,niobium-tantalum and other resources.In recent years,the mining industry in this country has been rising and attracting many foreign companies to invest,including international mining giants such as Vale,Rio Tinto and large mining enterprises of China.This paper systematically studies the mineral resources endowment,exploration and development situations of natural gas,graphite,titanium-zircon placer deposits,niobium-tantalum,gold,iron and other strategic minerals in Mozambique,comprehensively analyzes the mining investment environment and the current situation of exploration and development of Chinese enterprises in Mozambique,and replans four safeguard areas of strategic mineral resources in critical short supply.Mozambique generally has good prospects of mining investment and a stable foundation for cooperation with China.Chinese enterprises can focus on oil and natural gas,graphite,titanium,zirconium,niobium,tantalum,and iron,which complement the needs of China,expand the mining capacity cooperation,and improve the ability to secure strategic mineral resources supply.

China-Arab Energy Cooperation: Construct new Energy Silk Road

It is an important part of the Belt and Road initiative that Chinaand Arab countries to strengthen energy cooperation and jointlybuild the energy Silk Road. China-Arab has made remarkable progressin energy cooperation, especially in the fields of oil and gascooperation and new energy cooperation. China and Arab countriesare also strengthening strategic docking, promoting energytransition and cooperation in the field of new energy, and workingto form a clean energy production and modern energy consumptionsystem. China and Arab countries should deepenenergy cooperation by taking their complementary advantages,improve the docking mechanism of energy cooperation, promotecooperation in the whole energy industry chain, and avoid geopoliticalrisks through co-development. In the future, the energytransition will also bring great opportunities for deepening China-Arab energy cooperation. At the same time, political and economicrisks will still be an important challenge for China-Arabenergy cooperation. However, the sound political foundationbetween China and Arab countries is the long-term advantage ofChina-Arab energy cooperation.

ComplexTrans-Global Rail-Road Transportation System Economical and Clustered Individual and Individualised Public Transport also Prevents the Spread of Covid 19

Land transport can no longer meet the requirements.European transport can be described by these words−crowded motorways and cities,dangerous emissions,ubiquitous traffic accidents,delays,expensive railways.Solutions are being sought to transfer a large part of passengers and especially freight transport to(high-speed)rail,and efforts are moving towards electromobility,car-sharing,5G-connectivity,autonomous driving,MaaS(Mobility as a Service)-coordinated transport or hyperloop-type solutions.However,all these solutions have additional challenges and limitations.Solutions are not being searched where they really exist-in the mutual adaptation of road and rail vehicles and their deep cooperation.The ComplexTrans project shows that simply adapting the dimensions and functions of road and rail vehicles can eliminate(or at least significantly reduce)all the problems of existing land transport.The main features of the ComplexTrans system are sufficient parking spaces,reduction of urban and non-urban congestion,electric vehicles with unlimited range and cheaper than standard cars,cheaper and more accessible battery charging,“autonomous ride”,solving the overlap between passenger and freight rail transport and making it self-financing,transferring intercity freight transport to rail,replacing part of continental air transport and many others.The cost-effective and clustered individual transport and individualised public transport of the ComplexTrans system also bring very significant reductions in the risk of transmission of covid-19 and other contagious diseases during transport.

Energy transfer in Tb^(3+),Yb^(3+) codoped Lu_2O_3 near-infrared downconversion nanophosphors

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 Lu2O3：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.

Cooperative Spectrum Sensing Algorithms Based on Correlation Matrix in Cognitive Radio Networks

Cooperative energy spectrum sensing has been widely applied in cognitive radio （CR） networks. In this paper, two cooperative sensing algorithms based on the received signals＇ correlation matrix were proposed. The first proposed algorithm made use of both diagonal elements and non-diagonal elements in the cooperative scheme. In the second algorithm, when the sensing station can obtain the information of the channel gains between the primary user and the sensing nodes, the weighted linear model can be adopted to improve the sensing performance. This paper analyzed the effectiveness of these two proposed coopera- tive algorithms and demonstrated that they can considerably improve the sensing performance compared with the traditional linear cooperative sensing algorithms. Simulation results showed that the sensing performance can be significantly enhanced by using the proposed algorithms, especially when the number of cooperative nodes is large.

The potential of energy cooperation between China and Australia under the Belt and Road Initiative

While there is a proliferation of studies on China’s Belt and Road Initiative(BRI),there is a gap in the literature in terms of an exploration of the costs and benefits from the perspective of the energy sector,in both the areas of sectoral development and energy transition.This paper uses Australia as a case study.The paper is the first to quantify the impact of the BRI in the energy sector,and the analysis informs the current debates on the BRI in Australia.We find that energy cooperation under the BRI enhances the performance of energy companies,but the Chinese energy investment in Australia faces mounting challenges.We suggest some areas for cooperation and such cooperation could be extended to third countries.Amid the increasing trade and political tensions,the two countries need continued,level-headed discussions and debates about the potential cooperation areas at all levels.

Protecting China’s Energy Interests in the Middle East

In recent years,due to the political unrest in the Middle East,partnership on energy between China and Arab countries has been developing with fluctuations.Although oil and gas trade grew steadily as usual,cooperation in downstream industries,which was affected by the upheavals in the Middle East,was not entirely successful.Regarding energy issues,cooperation between China and the Middle East is the mainstream as China needs oil and gas from the Middle East and the Middle East needs the Chinese market,which is the foundation for bilateral cooperation.As long as the two sides make joint efforts,there must be a breakthrough in energy partnership.

China’s Energy Cooperation with Middle East Oil-producing Countries

China is rich in coal, but insufficient in petroleum and gas. The energy shortage is not a general shortage but a structural imbalance. In recent years, China's dependence on foreign oil supplies keeps increasing to meet the needs of China's rapid economic growth. China's top leadership, for this goal, has committed itself to energy diplomacy and vigorously promoted China's energy cooperation with Middle East oil-producing countries. In the current conditions, carrying out energy cooperation with the Middle East oil-producing countries is inevitable and beneficial to China’s security. China and the Middle East oil-producing countries have maintained friendly and cooperative relations: mutual political, economic complementarities and cultural fusion, which create a favorable environment for cooperation for extracting and removing the Middle East oil. As for the problems and difficulties exposed in carrying out energy cooperation in the Middle East, China should bravely face them and seriously resolve them.

Celanese Joins U.S.-China Energy Cooperation Program as Founding Management Board Member

Celanese Corporation has become a foundingcorporate member of the U.S.-China EnergyCooperation Program (ECP) and joined theentity’s founding management board.Celaneseannounced on December 23rd,2009.This reaffirms the company’s commitmentto environmentally sustainable growth inChina,the company’s fastest-growingregion.The mission of ECP,a private-sectorinitiated,managed and financedorganization,is to facilitate the adoption

Efficient near-infrared quantum cutting by Ce^(3+)-Yb^(3+) couple in GdBO_3 phosphors

Ce3＋ and Yb3＋ co-activated GdBO3 phosphors were prepared by a conventional solid-state reaction method. X-ray powder diffraction, photoluminescent spectra and decay curves were used to characterize their structural and luminescent properties. An efficient near-infrared （NIR） quantum cutting （QC） from the phosphors was observed, which involved the emission of two low-energy NIR photons （around 971 nm） from an absorbed ultra-violet （UV） photon at 358 nm via a cooperative energy transfer （CET） from Ce3＋ to Yb3＋ ions. The theoretical quantum efficiency was calculated and the maximum efficiency approached up to 164% before reaching the critical concentration quenching threshold. Our results demonstrated that these phosphors might find potential application in improving the efficiency of silicon based solar cells.