China＇s cormaaunications industry is an important part of the electronic information industry, and plays a significant role in the national informatization process. In 2006, China issued its National Plans for Medium...China＇s cormaaunications industry is an important part of the electronic information industry, and plays a significant role in the national informatization process. In 2006, China issued its National Plans for Medium and Long-term Development of Science and Technology （2006-2020） （NPMLDST）. Since 2006, there has been a rapid increase in the number of citations of China＇s interna- tional papers in the field of communications. In accordance with the goals listed in the NPMLDST, China needs to over- take several competitors by 2020 to be among the top five countries in the field of natural science field. By comparing two Essential Science Indicators （ESI） （i.e., the total number of citations and the number of citations per paper） for China and other countries, China＇s annual growth rate is found to exceed that of other influential countries in the field of sci- ence and technology, and exhibits evident growth-type characteristics. Besides, our study also shows that the short- age of high-quality academic papers in China is the main obstacle to improving the impact of China＇s academic publications.展开更多
We investigate the average Level Crossing Rate （LCR） and Average Fading Duration （AFD） of multiuser single relay co- operation wireless uplinks over independent and non-identically distributed （i.ni.d） Ray- leig...We investigate the average Level Crossing Rate （LCR） and Average Fading Duration （AFD） of multiuser single relay co- operation wireless uplinks over independent and non-identically distributed （i.ni.d） Ray- leigh fading channels. We first present the statistical analyses of the first-hop equivalent envelope. Then, we investigate the LCR and AFD of an equivalent end-to-end envelope, and present the closed-form solutions to LCR and AFD, which are given with integral forms. Finally, we derive the Laplace approximations of LCR and AFD as well as the upper and lower bounds. The numerical results of LCR show that the upper bound is tight. For multi user systems with different number of mobile users, the analyses indicate that the LCRs are approximately the same at the low level of the envelope. envelope However, there are at the high level of the reasonable differences among the curves of LCRs. Due to that fact that AFD is the inverse function of LCR, the results for AFD are the opposite.展开更多
Quantum computation requires coherently controlling the evolutions of qubits.Usually,these manipulations are implemented by precisely designing the durations(such as theπ-pulses)of the Rabi oscillations and tunable i...Quantum computation requires coherently controlling the evolutions of qubits.Usually,these manipulations are implemented by precisely designing the durations(such as theπ-pulses)of the Rabi oscillations and tunable interbit coupling.Relaxing this requirement,herein we show that the desired population transfers between the logic states can be deterministically realized(and thus quantum computation could be implemented)both adiabatically and non-adiabatically,by performing the duration-insensitive quantum manipulations.Our proposal is specifically demonstrated with the surface-state of electrons floating on the liquid helium,but could also be applied to the other artificially controllable systems for quantum computing.展开更多
基金supported by National High-tech R&D Program of China (863 Program) under Grant No.2011AA01A206
文摘China＇s cormaaunications industry is an important part of the electronic information industry, and plays a significant role in the national informatization process. In 2006, China issued its National Plans for Medium and Long-term Development of Science and Technology （2006-2020） （NPMLDST）. Since 2006, there has been a rapid increase in the number of citations of China＇s interna- tional papers in the field of communications. In accordance with the goals listed in the NPMLDST, China needs to over- take several competitors by 2020 to be among the top five countries in the field of natural science field. By comparing two Essential Science Indicators （ESI） （i.e., the total number of citations and the number of citations per paper） for China and other countries, China＇s annual growth rate is found to exceed that of other influential countries in the field of sci- ence and technology, and exhibits evident growth-type characteristics. Besides, our study also shows that the short- age of high-quality academic papers in China is the main obstacle to improving the impact of China＇s academic publications.
基金supported by the Natural Science Foundation of China under Grant No.61261015the 973 Project under Grant No.2013CB329104+4 种基金the National Natural Science Foundation of China under Grants No. 61071090,No. 61171093the Key Projects under GrantsNo. 2011ZX03005-004-003, No. BK2011027the China Postdoctoral Science Foundation under Grant No. 2012M521105Research Fund for the Doctoral Program of Higher Educationof China under Grant No. 20113223110001the project 11KJA510001 and PAPD
文摘We investigate the average Level Crossing Rate （LCR） and Average Fading Duration （AFD） of multiuser single relay co- operation wireless uplinks over independent and non-identically distributed （i.ni.d） Ray- leigh fading channels. We first present the statistical analyses of the first-hop equivalent envelope. Then, we investigate the LCR and AFD of an equivalent end-to-end envelope, and present the closed-form solutions to LCR and AFD, which are given with integral forms. Finally, we derive the Laplace approximations of LCR and AFD as well as the upper and lower bounds. The numerical results of LCR show that the upper bound is tight. For multi user systems with different number of mobile users, the analyses indicate that the LCRs are approximately the same at the low level of the envelope. envelope However, there are at the high level of the reasonable differences among the curves of LCRs. Due to that fact that AFD is the inverse function of LCR, the results for AFD are the opposite.
基金supported by the National Natural Science Foundation of China(Grant Nos.90921010 and 11174373)the National FundamentalResearch Program of China(Grant No.2010CB-923104)+1 种基金the National Research Foundation and Ministry of Education,Singapore(Grant No.WBS:R-710-000-008-271)the 2013 Doctoral Innovation funds of Southwes tJiaotong University and the Fundamental Research Funds for the Central Universities
文摘Quantum computation requires coherently controlling the evolutions of qubits.Usually,these manipulations are implemented by precisely designing the durations(such as theπ-pulses)of the Rabi oscillations and tunable interbit coupling.Relaxing this requirement,herein we show that the desired population transfers between the logic states can be deterministically realized(and thus quantum computation could be implemented)both adiabatically and non-adiabatically,by performing the duration-insensitive quantum manipulations.Our proposal is specifically demonstrated with the surface-state of electrons floating on the liquid helium,but could also be applied to the other artificially controllable systems for quantum computing.
