The aim of this paper is to give direct and converse theorems for the approximation by using a discretely defined method Ln (see D. H. Mache [10], which is a modification of the Lagrange operator. Furthermore we obtai...The aim of this paper is to give direct and converse theorems for the approximation by using a discretely defined method Ln (see D. H. Mache [10], which is a modification of the Lagrange operator. Furthermore we obtain with a matrix construction technique (see M. D. Ye and D. X. Zhou [11]) a Lagrange-type operator n, for which we get a characterization for Lipschitz functions by the approximation rate of these methods.展开更多
Pollutant gases emitted from the civil jet are doing more and more harm to the environ- ment with the rapid development of the global commercial aviation transport. Low environmental impact has become a new requiremen...Pollutant gases emitted from the civil jet are doing more and more harm to the environ- ment with the rapid development of the global commercial aviation transport. Low environmental impact has become a new requirement for aircraft design. In this paper, estimation method for emis- sion in aircraft conceptual design stage is improved based on the International Civil Aviation Orga- nization (ICAO) aircraft engine emissions databank and the polynomial curve fitting methods. The greenhouse gas emission (CO2 equivalent) per seat per kilometer is proposed to measure the emis- sions. An approximate sensitive analysis and a multi-objective optimization of aircraft design for tradeoff between greenhouse effect and direct operating cost (DOC) are performed with five geom- etry variables of wing configuration and two flight operational parameters. The results indicate that reducing the cruise altitude and Mach number may result in a decrease of the greenhouse effect but an increase of DOC. And the two flight operational parameters have more effects on the emissions than the wing configuration. The Pareto-optimal front shows that a decrease of 29.8% in DOC is attained at the expense of an increase of 10.8% in greenhouse gases.展开更多
In this paper, we propose certain different design ideas on a novel topic in quantum cryptography — quantum operation sharing(QOS). Following these unique ideas, three QOS schemes, the "HIEC"(The scheme who...In this paper, we propose certain different design ideas on a novel topic in quantum cryptography — quantum operation sharing(QOS). Following these unique ideas, three QOS schemes, the "HIEC"(The scheme whose messages are hidden in the entanglement correlation), "HIAO"(The scheme whose messages are hidden with the assistant operations) and "HIMB"(The scheme whose messages are hidden in the selected measurement basis), have been presented to share the single-qubit operations determinately on target states in a remote node. These schemes only require Bell states as quantum resources. Therefore, they can be directly applied in quantum networks, since Bell states are considered the basic quantum channels in quantum networks. Furthermore, after analyse on the security and resource consumptions, the task of QOS can be achieved securely and effectively in these schemes.展开更多
By using poled-polymer/silicon slot waveguides in the active region and the Pockels effect of the poled-polymer,we propose a kind of Mach-Zehnder interferometer(MZI) electro-optic(EO) switch operated at 1 550 nm.Struc...By using poled-polymer/silicon slot waveguides in the active region and the Pockels effect of the poled-polymer,we propose a kind of Mach-Zehnder interferometer(MZI) electro-optic(EO) switch operated at 1 550 nm.Structural parameters are optimized for realizing normal switching function.Dependencies of switching characteristics on the slot waveguide parameters are investigated.For the silicon strip with dimension of 170 nm×300 nm,as the slot width varies from 50 nm to 100 nm,the switching voltage can be as low as 1.0 V with active region length of only 0.17–0.35 mm,and the length of the whole device is only about 770–950 μm.The voltage-length product of this switching structure is only 0.17–0.35 V·mm,and it is at least 19–40 times smaller than that of the traditional polymer MZI EO switch,which is 6.69 V·mm.Compared with our previously reported MZI EO switches,this switch exhibits some superior characteristics,including low switching voltage,compact device size and small wavelength dependency.展开更多
基金The second author is supported by the Alexander von Humboldt-Stiftung.
文摘The aim of this paper is to give direct and converse theorems for the approximation by using a discretely defined method Ln (see D. H. Mache [10], which is a modification of the Lagrange operator. Furthermore we obtain with a matrix construction technique (see M. D. Ye and D. X. Zhou [11]) a Lagrange-type operator n, for which we get a characterization for Lipschitz functions by the approximation rate of these methods.
基金supported by the Fundamental Research Funds for the Central Universities (NUAA NN2012071)China Postdoctoral Science Foundation (2011M500919)
文摘Pollutant gases emitted from the civil jet are doing more and more harm to the environ- ment with the rapid development of the global commercial aviation transport. Low environmental impact has become a new requirement for aircraft design. In this paper, estimation method for emis- sion in aircraft conceptual design stage is improved based on the International Civil Aviation Orga- nization (ICAO) aircraft engine emissions databank and the polynomial curve fitting methods. The greenhouse gas emission (CO2 equivalent) per seat per kilometer is proposed to measure the emis- sions. An approximate sensitive analysis and a multi-objective optimization of aircraft design for tradeoff between greenhouse effect and direct operating cost (DOC) are performed with five geom- etry variables of wing configuration and two flight operational parameters. The results indicate that reducing the cruise altitude and Mach number may result in a decrease of the greenhouse effect but an increase of DOC. And the two flight operational parameters have more effects on the emissions than the wing configuration. The Pareto-optimal front shows that a decrease of 29.8% in DOC is attained at the expense of an increase of 10.8% in greenhouse gases.
基金supported by the National Natural Science Foundation of China(Grant Nos.61272057,61572081 and 61502200)Beijing Higher Education Young Elite Teacher Project(Grant Nos.YETP0475and YETP0477)+2 种基金the Natural Science Foundation of Guangdong Province(Grant No.2014A030310245)the Fundamental Research Funds for the Central Universities(Grant No.21615313)the Youth Foundation of Heilongjiang University from January,2016
文摘In this paper, we propose certain different design ideas on a novel topic in quantum cryptography — quantum operation sharing(QOS). Following these unique ideas, three QOS schemes, the "HIEC"(The scheme whose messages are hidden in the entanglement correlation), "HIAO"(The scheme whose messages are hidden with the assistant operations) and "HIMB"(The scheme whose messages are hidden in the selected measurement basis), have been presented to share the single-qubit operations determinately on target states in a remote node. These schemes only require Bell states as quantum resources. Therefore, they can be directly applied in quantum networks, since Bell states are considered the basic quantum channels in quantum networks. Furthermore, after analyse on the security and resource consumptions, the task of QOS can be achieved securely and effectively in these schemes.
基金supported by the National Natural Science Foundation of China(Nos.61107021,61177027 and 61077074)the Ministry of Education of China(Nos.20110061120052 and 20120061130008)the Science and Technology Department of Jilin Province of China(No.20130522161JH)
文摘By using poled-polymer/silicon slot waveguides in the active region and the Pockels effect of the poled-polymer,we propose a kind of Mach-Zehnder interferometer(MZI) electro-optic(EO) switch operated at 1 550 nm.Structural parameters are optimized for realizing normal switching function.Dependencies of switching characteristics on the slot waveguide parameters are investigated.For the silicon strip with dimension of 170 nm×300 nm,as the slot width varies from 50 nm to 100 nm,the switching voltage can be as low as 1.0 V with active region length of only 0.17–0.35 mm,and the length of the whole device is only about 770–950 μm.The voltage-length product of this switching structure is only 0.17–0.35 V·mm,and it is at least 19–40 times smaller than that of the traditional polymer MZI EO switch,which is 6.69 V·mm.Compared with our previously reported MZI EO switches,this switch exhibits some superior characteristics,including low switching voltage,compact device size and small wavelength dependency.