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.

Energy efficiency enhancement of two-way amplifier forward relaying with channel estimation error

In order to save energy consumption of two-way amplifier forward(AF) relaying with channel estimation error, an energy efficiency enhancement scheme is proposed in this work. Firstly, through the analysis of two-way AF relaying mode with channel estimation error, the resultant instantaneous SNRs at end nodes is obtained. Then, by using a high SNR approximation, outage possibility is acquired and its simple closed-form expression is represented. Specially, for using the energy resource more efficiently, a low-complexity power allocation and transmission mode selection policy is proposed to enhance the energy efficiency of two-way AF relay system. Finally, relay priority region is identified in which cooperative diversity energy gain can be achieved. The computer simulations are presented to verify our analytical results, indicating that the proposed policy outperforms direct transmission by an energy gain of 3 dB at the relative channel estimation error less than 0.001. The results also show that the two-way AF relaying transmission loses the two-way AF relaying transmission loses its superiority to direct transmission in terms of energy efficiency when channel estimation error reaches 0.03.

Energy Efficiency Analysis of Cellular Networks with Cooperative Relays via Stochastic Geometry

Cooperative relaying is a promising technology that can improve the spectral and energy efficiency of cellular networks. However, the deployed relays consume a lot of energy and system resources. To improve the energy efficiency of the relay-assisted cellular networks, this paper considers the use of energy harvesting(EH) on relay nodes. A random sleeping strategy is also introduced in macro base stations(MBS) as a possible method to reduce energy consumption. In this paper, an analytical model is proposed to investigate the energy efficiency of cellular networks with EH relays and sleep mode strategy. Numerical results confirm a significant energy efficiency gain of the proposed networks comparing to the cellular networks with non-EH relays and MBSs without sleep mode strategy. The effects of the density and transmit power of MBSs on energy efficiency are also given through simulations.

The Belt and Road Initiatives and China＇s International Energy Cooperation： Progress, Mechanisms, and Recommendations

China＇s international energy cooperation and energy security are important parts of The Belt and Road initiatives. China and the countries along the Belt and Road continue to promote cooperation, actively use the existing bilateral and multilateral cooperation mechanisms to promote the regional and inter-regional energy cooperation. Countries along the Belt and Road are rich in oil and gas resources; their demand on the diversification of export meet with the diversification demand on imports of consumption countries; and their oil refining and chemical technology as well as construction capacity is weak, which provides a lot of new opportunities in cooperation for Chinese enterprises. However, the energy cooperation of Chinese enterprises are also facing some challenges in the complex environment of energy cooperation, the interference of big powers, non-traditional security threats, and energy policy factors. Finally, the paper puts forward the strategic thinking of China＇s international energy cooperation under the new situation.

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.

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.

The Opportunities, Challenges and Countermeasures of Energy Cooperation between China and Kazakhstan under the Background of ＂One Belt and One Road＂

Relative to countries such as Russia, the United States, and Europe, China has only recently occupied a place in the energy sector in Kazakhstan. However, after 10 years of hard work, China has come to the fore and the fierce energy competition in Kazakhstan has become an important energy trading partner of Central Asian countries. Therefore, we can learn a lot of experience and lessons from our emphasis on cooperation with China＇s energy trade and research in Central Asian countries. Against the backdrop of fierce international energy competition and the deep implementation of the ＂One Belt and One Road＂ initiative, it is like a double-edged sword for energy trade cooperation between China and Central Asian countries, problem. How China seizes opportunities, resolves challenges, and further deepens pragmatic cooperation in the energy sector with Central Asian countries so as to better protect the country＇ s energy security is a very real issue.

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

Bulgaria,Boosting Energy Cooperation with China——Interview with Deputy Minister Yaneva,Ministry of Economy and Energy,the Republic of Bulgaria

Deputy Minister Yaneva of Economy and Energy,the Republic of Bul- garia,a nice lady with outstanding talents,headed a delegation of Bulgaria to visit China in late June,for the participation at the 13th Bulgarian-Chi- nese Intergovernmental Commission for Economic,Trade,Scientific and Technical Cooperation.As an important instrument,the Joint Commission played a significant role in promoting the overall development of the bilat- eral economic relations. China's Foreign Trade interviewed Deputy Minister Yaneva and she gave very constructive suggestions on promoting the bilateral economic and trade cooperation between the two countries,especially in the area of energy cooperation.The following is a written interview with Deputy Min- ister Yaneva.

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.

Optimization of sensing time and cooperative user allocation for OR-rule cooperative spectrum sensing in cognitive radio network

In order to improve the throughput of cognitive radio(CR), optimization of sensing time and cooperative user allocation for OR-rule cooperative spectrum sensing was investigated in a CR network that includes multiple users and one fusion center. The frame structure of cooperative spectrum sensing was divided into multiple transmission time slots and one sensing time slot consisting of local energy detection and cooperative overhead. An optimization problem was formulated to maximize the throughput of CR network, subject to the constraints of both false alarm probability and detection probability. A joint optimization algorithm of sensing time and number of users was proposed to solve this optimization problem with low time complexity. An allocation algorithm of cooperative users was proposed to preferentially allocate the users to the channels with high utilization probability. The simulation results show that the significant improvement on the throughput can be achieved through the proposed joint optimization and allocation algorithms.

Strategy of Oil and Gas Cooperation in the Belt and Road Initiative

Over the past two decades, as the main battlefield of China's international energy cooperation, countries along the Belt and Road have had good foundations in the foreign investment. Through China's efforts to build the Belt and Road, energy cooperation has enjoyed first-mover advantages. Looking ahead, the countries along the Belt and Road are predicted to enjoy a promising future in energy cooperation because of their abundant energy resources, their role as complements to China's economic development, and their vast amounts of cooperation potential. At the same time, we are also keenly aware that there are a number of risks caused by geopolitics, policy changes, price fluctuations and legal compliance in energy cooperation among the countries along the Belt and Road. Moreover, it is urgent for Chinese enterprises to enhance their international capabilities. In this context, it is necessary to further maintain and make full use of their first-mover advantages and play a guiding and demonstrating role. Enterprises should actively adapt to new changes, while the government should make progress in policy coordination, facility connectivity, unimpeded trade, financed integration and people-to-people bonds, so as to keep deepening international energy cooperation and to build an energy silk road and a community with a shared future for energy.

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.

The Belt and Road Initiatives and China-GCC Relations

Gulf Cooperation Council （GCC） countries are the main countries of the West Asia, they are rich in oil and natural gas, and very important in the world political and economic arena. In recent years, the trade volume between China and six GCC countries has been rising. The paper analyzes the importance and the prospect of China-GCC Free Trade Area negotiations. The two sides should take positive action to further close dialogue mechanism between the two sides, restart the negotiations on the free trade zone between China and GCC countries as soon as possible, and reach a win-win agreement.

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.

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.

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.

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...

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.