In this paper,a model with two mutual learning neural networks named Tree Parity Machine(TPM) is firstly introduced,as well as its cryptographic property of weight synchronization with that of chaos cryptography is co...In this paper,a model with two mutual learning neural networks named Tree Parity Machine(TPM) is firstly introduced,as well as its cryptographic property of weight synchronization with that of chaos cryptography is comparatively discussed. A full empirical study on the stability and security of the TPM weight synchronization is conducted in detail. Then two improvement methods for the weight synchronization are proposed. Experiment results show that the improved TPM synchronization model can be efficiently against the third party attack. At last,a lightweight TPM-based key management scheme is proposed for TinySec on wireless sensor networks,which is full implemented on the Mica2 node and the performance test result is acceptable.展开更多
A new detector array characterized by compact structure and large solid-angle coverage was designed for radioactive ion beam(RIB)experiments and measuring multi-particle correlations.A Monte Carlo simulation was perfo...A new detector array characterized by compact structure and large solid-angle coverage was designed for radioactive ion beam(RIB)experiments and measuring multi-particle correlations.A Monte Carlo simulation was performed to explore the effects of beam drifts in different directions and distances on the angular distribution of the Rutherford scattering,as measured by the detector array.The results indicate that when the beam drift distance is less than 2.0 mm,the symmetry of the detector array can maintain a count error of less than 5%.This confirms the property of the detector array for RIB experiments.Furthermore,the simulation was validated through the elastic scattering angular distributions of 6;7 Li measured by the detector array in 6;7Li t209 Bi experiments at different energies.展开更多
Employing the method which can be used to demonstrate the infinite conservation laws for the standard Kortewegde Vries （KdV） equation, we prove that the variable-coeFficient KdV equation under the Painlevé test...Employing the method which can be used to demonstrate the infinite conservation laws for the standard Kortewegde Vries （KdV） equation, we prove that the variable-coeFficient KdV equation under the Painlevé test condition also possesses the formal conservation laws.展开更多
Refs 1 and 2 provide the definition of the concepts of‘potential infinity’(poi)and actual infinity(aci);Ref 3 discusses and verifies that poi and aci are a pair of contradictory opposites without intermediate(p,-p)....Refs 1 and 2 provide the definition of the concepts of‘potential infinity’(poi)and actual infinity(aci);Ref 3 discusses and verifies that poi and aci are a pair of contradictory opposites without intermediate(p,-p).The second part of this paper,i.e.,§2,further discusses the manners in which a variable x approaches infinitely to its limit x0 using the poi and aci methods and concludes that,in any system compatible with both poi and aci, the two approaching manners are also a pair of contradictory opposites without intermediate (A,-A).Finally,on the basis of this conclusion,we reexamine the fundamental question of Leibniz’s Secant and Tangent Lines in calculus and the limit theory and offer our analysis and raise new questions.展开更多
From the perspective of potential infinity (poi) and actual infinity, Ref [4] has confirmed that poi and aci are in 'unmediated opposition' (P,﹁P ) whether in ZFC or not; it has further been proved that the m...From the perspective of potential infinity (poi) and actual infinity, Ref [4] has confirmed that poi and aci are in 'unmediated opposition' (P,﹁P ) whether in ZFC or not; it has further been proved that the manners in which a variable infinitely approaches its limit also satisfy the law of intermediate exclusion. With these results as theoretical bases, this paper attempts to provide an accurate and strict logical-mathematical interpretation of the incompatibility of Leibniz's secant and tangent lines in the medium logic system from the perspective of logical mathematics.展开更多
In order to study the effect of tensor force,we plan to perform a(p,d)reaction with a 400–1600 Me V proton beam on the RIBLL2 at Lanzhou.Based on the experimental conditions of RIBLL2,a Monte Carlo method is used to ...In order to study the effect of tensor force,we plan to perform a(p,d)reaction with a 400–1600 Me V proton beam on the RIBLL2 at Lanzhou.Based on the experimental conditions of RIBLL2,a Monte Carlo method is used to simulate(p,d)reaction process.The distributions of primary beam and scattered deuterons are given on the target and at the F1,F2,F3,and F4 positions.Considering the yield of the deuteron,to separate the produced deuteron from the background particles,the target thickness is optimized.To obtain a clear particle identification spectrum by time of flight(TOF)and energy loss(?E),the distance between the two detectors,as well as the energy and timing resolution of detectors are simulated.As a result,the distance between F2 and F4 is fit for that of TOF.After taking into account the particle distribution at F4,both sizes of Multi-Wire Drift Chamber,namely MWDC2 and MWDC3,are selected to be 50 mm×50 mm.展开更多
A two-band Hamiltonian for β-graphyne is derived by the k·p method.The energy dispersions around the Dirac points are analytically obtained depending on the relative amplitude of the hopping terms t_(1)/t_(2),an...A two-band Hamiltonian for β-graphyne is derived by the k·p method.The energy dispersions around the Dirac points are analytically obtained depending on the relative amplitude of the hopping terms t_(1)/t_(2),and the Dirac cones are elliptical when -2t_(1)/t_(2)j.This interesting feature is useful for direction-dependent wave filter devices.展开更多
Abstract： Ref [5] provides a logical-mathematical explanation of the incompatibility ofLeibniz＇s secant and tangent lines in medium logic. However, the expression （＊）（△y/△x） ismeaningful and dy/dx is the tang...Abstract： Ref [5] provides a logical-mathematical explanation of the incompatibility ofLeibniz＇s secant and tangent lines in medium logic. However, the expression （＊）（△y/△x） ismeaningful and dy/dx is the tangent slope） derived from ⑦ and ⑧ in §4 of Ref [5] is unimaginablewithin the framework of two-valued logic, why shouldn＇t the same conflicting concluslon be reached in the medium logic calculus？ This paper has subjected these questions to careful logical analysis, and approached them from the perspective of logical mathematics. As the two approaches have led to the identical conclusion, the paper thereby rigorously and thoroughlv answers these questions.展开更多
Effects ofΛΛω−tensor coupling on the spin symmetry ofΛspectra inΛ−nucleus systems are studied using relativistic mean-field theory.Taking 12C+Λas an example,it is found that the tensor coupling enlarges the spin...Effects ofΛΛω−tensor coupling on the spin symmetry ofΛspectra inΛ−nucleus systems are studied using relativistic mean-field theory.Taking 12C+Λas an example,it is found that the tensor coupling enlarges the spin−orbit splittings ofΛby a factor of 5 but has a negligible effect on the wave functions ofΛ.Similar conclusions are observed in otherΛ−nuclei,including ^(16)O+Λ,^(40)Ca+Λand ^(208)Pb+Λ.It is indicated that the spin symmetry in anti-lambda-nucleus systems is still a good approximation irrespective of the tensor coupling.展开更多
The third-order nonlinear optical properties of water-soluble Cu Se nanocrystals are studied in the near infrared range of 700-980 nm using a femtosecond pulsed laser by the Z-scan technique. It is observed that the n...The third-order nonlinear optical properties of water-soluble Cu Se nanocrystals are studied in the near infrared range of 700-980 nm using a femtosecond pulsed laser by the Z-scan technique. It is observed that the nonlinear optical response of Cu Se nanocrystals is sensitively dependent on the excitation wavelength and exhibits the enhanced nonlinearity compared with other selenides such as ZnSe and CdSe. The W-shaped Z-scan trace, a mixture of the reversed saturated absorption and saturated absorption, is observed near the plasmon resonance band of Cu Se nanocrystals, which is attributed to the state-filling of free carriers generated by copper vacancies (self-doping effect) of Cu Se nanocrystals as well as the hot carrier thermal effect upon intense femtosecond laser excitation. The large nonlinear optical response and tunable plasmonic band make Cu Se nanocrystals promising materials for applications in ultra-fast all-optical switching devices as well as nonlinear nanosensors.展开更多
Ubiquitous sensors, devices, networks, and information are paving the way to smart cities in which computation and intelligence are pervasive. This enables reliable, relevant intormation and services to he accessible ...Ubiquitous sensors, devices, networks, and information are paving the way to smart cities in which computation and intelligence are pervasive. This enables reliable, relevant intormation and services to he accessible to all people. Smart objects, homes, hospitals, manufacturing, and systerns will eventually be present in every city.展开更多
This paper proposes a content addres sable storage optimization method, VDeskCAS, for desktop virtualization storage based disaster backup storage system. The method implements a blocklevel storage optimization, by em...This paper proposes a content addres sable storage optimization method, VDeskCAS, for desktop virtualization storage based disaster backup storage system. The method implements a blocklevel storage optimization, by employing the algorithms of chunking image file into blocks, the blockffmger calculation and the block dedup li cation. A File system in Use Space （FUSE） based storage process for VDeskCAS is also introduced which optimizes current direct storage to suit our content addressable storage. An interface level modification makes our system easy to extend. Experiments on virtual desktop image files and normal files verify the effectiveness of our method and above 60% storage volume decrease is a chieved for Red Hat Enterprise Linux image files. Key words： disaster backup; desktop virtualization; storage optimization; content addressable storage展开更多
As the number of Virtual Machines(VMs) consolidated on single physical server increases with the rapid advance of server hardware,virtual network turns complex and frangible.Modern Network Security Engines(NSE) are in...As the number of Virtual Machines(VMs) consolidated on single physical server increases with the rapid advance of server hardware,virtual network turns complex and frangible.Modern Network Security Engines(NSE) are introduced to eradicate the intrusions occurring in the virtual network.In this paper,we point out the inadequacy of the present live migration implementation,which hinders itself from providing transparent VM relocation between hypervisors equipped with Network Security Engines(NSE-H).This occurs because the current implementation ignores VM-related Security Context(SC) required by NSEs embedded in NSE-H.We present the CoM,a comprehensive live migration framework,for NSE-H-based virtualization computing environment.We built a prototype system on Xen hypervisors to evaluate our framework,and conduct experiments under various realistic application environments.The results demonstrate that our solution successfully fixes the inadequacy of the present live migration implementation,and the performance overhead is negligible.展开更多
We demonstrate a highly compact third-order elliptical micro-ring add-drop filter based on a silicon-on-insulator wafer. The elliptical micro-ring resonator has a major radius of 6μm （minor radius of 4.112μm） and ...We demonstrate a highly compact third-order elliptical micro-ring add-drop filter based on a silicon-on-insulator wafer. The elliptical micro-ring resonator has a major radius of 6μm （minor radius of 4.112μm） and a large free spectral range of 18 nm. Experimental results show a box-like channel dropping response, which has a 3 dB bandwidth of -2.7nm, high out-of-band signal rejection of around 40dB and a very low drop loss （〈0.5dB）. Simulation agrees well with the experiments. The footprint of the whole chip is only 0.0003mm2.展开更多
A variable-coemcient Kadomtsev-Petviashvili equation is investigated. The Painlev6 analysis leads to its explicit Painlevd-integrable conditions. An auto-Backlund transformation and the bilinear form are presented via...A variable-coemcient Kadomtsev-Petviashvili equation is investigated. The Painlev6 analysis leads to its explicit Painlevd-integrable conditions. An auto-Backlund transformation and the bilinear form are presented via the truncated Painlev6 expansion and symbolic computation. Several families of new analytic solutions arepresented, including the soliton-like and periodic solutions.展开更多
Ferromagnetism in the one-dimensional Hubbard model with the next-nearest-neighbor hopping is explored by using the exact-diagonalization method in a small cluster and the equation-of-motion method in the thermodynami...Ferromagnetism in the one-dimensional Hubbard model with the next-nearest-neighbor hopping is explored by using the exact-diagonalization method in a small cluster and the equation-of-motion method in the thermodynamic limit with electron density n = 3/2. With these two complementary methods, it is found that an intermediate value of the next-nearest- neighbor hopping amplitude tl tends to stabilize the fully polarized ferromagnetic state under the condition that the on-site coulomb interaction U is sufficiently large in our model. The ground-state phase diagram of the model is presented in the tl-U plane.展开更多
A four-channel integrated optical wavelength de-multiplexer is experimentally illustrated on a silicon-on-insulator （SO1） substrate. With the aid of cascaded micro-ring resonators, the whole performance of the wavel...A four-channel integrated optical wavelength de-multiplexer is experimentally illustrated on a silicon-on-insulator （SO1） substrate. With the aid of cascaded micro-ring resonators, the whole performance of the wavelength de- multiplexer is improved, such as 3 dB bandwidth and channel crosstalk. Based on the transform matrix theory, a four-channel wavelength de-multiplexer with average channel spacing 4.5±0.5 nm （3 dB bandwidth - 2 ± 0.5 nm） is demonstrated at telecommunication bands. For each channel, the extinction at the adjacent channel is below -39dB and the out-of-band rejection ratio is up to 40dB. The channel dropping loss is below 5dB in the five FSR spectral response periods （near 100 nm）.展开更多
We propose a new scheme of realizing spin-polarized currents in a double quantum dot system.In the presence of Rashba spin-orbit coupling interactions and different Zeeman splittings of each quantum dot,the currents a...We propose a new scheme of realizing spin-polarized currents in a double quantum dot system.In the presence of Rashba spin-orbit coupling interactions and different Zeeman splittings of each quantum dot,the currents are spin-polarized.The polarization can be controlled by tuning the strength of Rashba spin-orbit coupling and external magnetic fields,which can produce nearly 100%spin-polarized currents.Furthermore,we explain and analyze the mechanism of the strongly spin-polarized currents.Lastly we give two phase diagrams to display our results.展开更多
We study theoretically the plasmon excitations in a two-dimensional electron gas （2DEG） with spin-orbit interactions （SOIs） embedded in a （11n） crystallographic plane. We demonstrate that the energy spectra and ...We study theoretically the plasmon excitations in a two-dimensional electron gas （2DEG） with spin-orbit interactions （SOIs） embedded in a （11n） crystallographic plane. We demonstrate that the energy spectra and dielectric functions between the 2DEGs embedded in different crystallographic planes can be related by a unitary transformation. Using the unitary transformation, we find that the anisotropy of plasmon excitations and the directional plasmon filtering （DPF） can be tuned by changing the strengths of SOIs in the high-index planes. There are two advantageous directions [110] and [nn2] for plasmon propagation. Moreover, the anisotropy and the DPF can be smeared out by tuning the strength ratio α/β between the Rashba SOI and the Dresselhaus SOI.展开更多
基金supported by the following funds:the Open Fund of the State Key Laboratory of Software Development Environment under Grant No.SKLSDE- 2009KF-2-01Beihang University, the National Basic Research Program of China (973 Program) under Grant No. 2005CB321901 and No.2010CB328106-3+1 种基金the Natural Science Foundation of China under Grant No.60773115the Open Fund of the Zhejiang Provincial Key Laboratory of Information Security
文摘In this paper,a model with two mutual learning neural networks named Tree Parity Machine(TPM) is firstly introduced,as well as its cryptographic property of weight synchronization with that of chaos cryptography is comparatively discussed. A full empirical study on the stability and security of the TPM weight synchronization is conducted in detail. Then two improvement methods for the weight synchronization are proposed. Experiment results show that the improved TPM synchronization model can be efficiently against the third party attack. At last,a lightweight TPM-based key management scheme is proposed for TinySec on wireless sensor networks,which is full implemented on the Mica2 node and the performance test result is acceptable.
基金the National Natural Science Foundation of China(Nos.11635015,U1832130,and 11975040)the State Key Laboratory of Software Development Environment(SKLSDE-2020ZX-16)+1 种基金the Continuous Basic Scientific Research Project(No.WDJC-2019-13)the Leading Innovation Project(Nos.LC192209000701 and LC202309000201).
文摘A new detector array characterized by compact structure and large solid-angle coverage was designed for radioactive ion beam(RIB)experiments and measuring multi-particle correlations.A Monte Carlo simulation was performed to explore the effects of beam drifts in different directions and distances on the angular distribution of the Rutherford scattering,as measured by the detector array.The results indicate that when the beam drift distance is less than 2.0 mm,the symmetry of the detector array can maintain a count error of less than 5%.This confirms the property of the detector array for RIB experiments.Furthermore,the simulation was validated through the elastic scattering angular distributions of 6;7 Li measured by the detector array in 6;7Li t209 Bi experiments at different energies.
基金Supported by the Key Project of Chinese Ministry of Education under Grant No 106033, the National Natural Science Foundation of China under Grant Nos 60372095 and 60772023, Open Fund of the State Key Laboratory of Software Development Environment under Grant No SKLSDE-07-001, Beijing University of Aeronautics and Astronautics, the National Basic Research Programme of China under Grant No 2005CB321901, the Green Path Programme of Air Force of the Chinese People＇s Liberation Army, the Cheung Kong Scholars Programme of the Ministry of Education of China and Li Ka Shing Foundation of Hong Kong.
文摘Employing the method which can be used to demonstrate the infinite conservation laws for the standard Kortewegde Vries （KdV） equation, we prove that the variable-coeFficient KdV equation under the Painlevé test condition also possesses the formal conservation laws.
基金Supported by the Open Fund of the State Key Laboratory of Software Development Environment(SKLSDE-2011KF-04)Supported by the Beihang University and by the National High Technology Research and Development Program of China(863 Program)(2009AA043303)
文摘Refs 1 and 2 provide the definition of the concepts of‘potential infinity’(poi)and actual infinity(aci);Ref 3 discusses and verifies that poi and aci are a pair of contradictory opposites without intermediate(p,-p).The second part of this paper,i.e.,§2,further discusses the manners in which a variable x approaches infinitely to its limit x0 using the poi and aci methods and concludes that,in any system compatible with both poi and aci, the two approaching manners are also a pair of contradictory opposites without intermediate (A,-A).Finally,on the basis of this conclusion,we reexamine the fundamental question of Leibniz’s Secant and Tangent Lines in calculus and the limit theory and offer our analysis and raise new questions.
基金Supported by the Open Fund of the State Key Laboratory of Software Development Environment(SKLSDE-2011KF-04)Supported by the National High Technology Research and Development Program of China (863 Program)(2009AA043303)
文摘From the perspective of potential infinity (poi) and actual infinity, Ref [4] has confirmed that poi and aci are in 'unmediated opposition' (P,﹁P ) whether in ZFC or not; it has further been proved that the manners in which a variable infinitely approaches its limit also satisfy the law of intermediate exclusion. With these results as theoretical bases, this paper attempts to provide an accurate and strict logical-mathematical interpretation of the incompatibility of Leibniz's secant and tangent lines in the medium logic system from the perspective of logical mathematics.
基金Supported by National Natural Science Foundation of China(Nos.11475013,11035007 and 11175011)State Key Laboratory of Software Development Environment(No.SKLSDE-2014ZX-08)+1 种基金Fundamental Research Funds for the Central Universitiesthe Key Laboratory of High Precision Nuclear Spectroscopy,Institute of Modern Physics,Chinese Academy of Sciences
文摘In order to study the effect of tensor force,we plan to perform a(p,d)reaction with a 400–1600 Me V proton beam on the RIBLL2 at Lanzhou.Based on the experimental conditions of RIBLL2,a Monte Carlo method is used to simulate(p,d)reaction process.The distributions of primary beam and scattered deuterons are given on the target and at the F1,F2,F3,and F4 positions.Considering the yield of the deuteron,to separate the produced deuteron from the background particles,the target thickness is optimized.To obtain a clear particle identification spectrum by time of flight(TOF)and energy loss(?E),the distance between the two detectors,as well as the energy and timing resolution of detectors are simulated.As a result,the distance between F2 and F4 is fit for that of TOF.After taking into account the particle distribution at F4,both sizes of Multi-Wire Drift Chamber,namely MWDC2 and MWDC3,are selected to be 50 mm×50 mm.
基金Supported by State Key Laboratory of Software Development Environment under Grant Nos SKLSDE-2013ZX-28 and SKLSDE-2013ZX-21the National Natural Science Foundation of China under Grant Nos 10974011 and 11174022the Innovation Foundation of BUAA for PhD Graduates under Grant No 30-2194.
文摘A two-band Hamiltonian for β-graphyne is derived by the k·p method.The energy dispersions around the Dirac points are analytically obtained depending on the relative amplitude of the hopping terms t_(1)/t_(2),and the Dirac cones are elliptical when -2t_(1)/t_(2)j.This interesting feature is useful for direction-dependent wave filter devices.
文摘Abstract： Ref [5] provides a logical-mathematical explanation of the incompatibility ofLeibniz＇s secant and tangent lines in medium logic. However, the expression （＊）（△y/△x） ismeaningful and dy/dx is the tangent slope） derived from ⑦ and ⑧ in §4 of Ref [5] is unimaginablewithin the framework of two-valued logic, why shouldn＇t the same conflicting concluslon be reached in the medium logic calculus？ This paper has subjected these questions to careful logical analysis, and approached them from the perspective of logical mathematics. As the two approaches have led to the identical conclusion, the paper thereby rigorously and thoroughlv answers these questions.
基金by the National Basic Research Program of China under Grant No 2007CB815000the National Natural Science Foundation of China under Grant Nos 11005004,10947013,and 10975008+2 种基金the State Key Laboratory of Software Development Environment under Grant No SKLSDE-2011ZX-18the Southwest University Initial Research Foundation Grant to Doctor(No SWU109011)the Fundamental Research Funds for the Central Universities under Grant No XDJK2010B007.
文摘Effects ofΛΛω−tensor coupling on the spin symmetry ofΛspectra inΛ−nucleus systems are studied using relativistic mean-field theory.Taking 12C+Λas an example,it is found that the tensor coupling enlarges the spin−orbit splittings ofΛby a factor of 5 but has a negligible effect on the wave functions ofΛ.Similar conclusions are observed in otherΛ−nuclei,including ^(16)O+Λ,^(40)Ca+Λand ^(208)Pb+Λ.It is indicated that the spin symmetry in anti-lambda-nucleus systems is still a good approximation irrespective of the tensor coupling.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11274302,11474276 and 11674240
文摘The third-order nonlinear optical properties of water-soluble Cu Se nanocrystals are studied in the near infrared range of 700-980 nm using a femtosecond pulsed laser by the Z-scan technique. It is observed that the nonlinear optical response of Cu Se nanocrystals is sensitively dependent on the excitation wavelength and exhibits the enhanced nonlinearity compared with other selenides such as ZnSe and CdSe. The W-shaped Z-scan trace, a mixture of the reversed saturated absorption and saturated absorption, is observed near the plasmon resonance band of Cu Se nanocrystals, which is attributed to the state-filling of free carriers generated by copper vacancies (self-doping effect) of Cu Se nanocrystals as well as the hot carrier thermal effect upon intense femtosecond laser excitation. The large nonlinear optical response and tunable plasmonic band make Cu Se nanocrystals promising materials for applications in ultra-fast all-optical switching devices as well as nonlinear nanosensors.
文摘Ubiquitous sensors, devices, networks, and information are paving the way to smart cities in which computation and intelligence are pervasive. This enables reliable, relevant intormation and services to he accessible to all people. Smart objects, homes, hospitals, manufacturing, and systerns will eventually be present in every city.
基金the Hi-tech Research and Development Program of China，the National Natural Science Foundation of China，the Beijing Natural Science Foundation，the Fundamental Research Funds for the Central Universities，the Fund of the State Key Laboratory of Software Development Environment
文摘This paper proposes a content addres sable storage optimization method, VDeskCAS, for desktop virtualization storage based disaster backup storage system. The method implements a blocklevel storage optimization, by employing the algorithms of chunking image file into blocks, the blockffmger calculation and the block dedup li cation. A File system in Use Space （FUSE） based storage process for VDeskCAS is also introduced which optimizes current direct storage to suit our content addressable storage. An interface level modification makes our system easy to extend. Experiments on virtual desktop image files and normal files verify the effectiveness of our method and above 60% storage volume decrease is a chieved for Red Hat Enterprise Linux image files. Key words： disaster backup; desktop virtualization; storage optimization; content addressable storage
基金supported by State Key Laboratory of Software Development Environment under Grant No. SKLSDE-2009ZX-02China Aviation Science Fund under Grant No.20081951National High Technical Research and Development Program of China (863 Program) under Grant No.2007AA01Z183
文摘As the number of Virtual Machines(VMs) consolidated on single physical server increases with the rapid advance of server hardware,virtual network turns complex and frangible.Modern Network Security Engines(NSE) are introduced to eradicate the intrusions occurring in the virtual network.In this paper,we point out the inadequacy of the present live migration implementation,which hinders itself from providing transparent VM relocation between hypervisors equipped with Network Security Engines(NSE-H).This occurs because the current implementation ignores VM-related Security Context(SC) required by NSEs embedded in NSE-H.We present the CoM,a comprehensive live migration framework,for NSE-H-based virtualization computing environment.We built a prototype system on Xen hypervisors to evaluate our framework,and conduct experiments under various realistic application environments.The results demonstrate that our solution successfully fixes the inadequacy of the present live migration implementation,and the performance overhead is negligible.
基金Supported by the National High Technology Research and Development Program of China under Grant No 2015AA016904the National Key Research and Development Plan of China under Grant No 2016YFB0402502the National Natural Science Foundation of China under Grant No 61275065
文摘We demonstrate a highly compact third-order elliptical micro-ring add-drop filter based on a silicon-on-insulator wafer. The elliptical micro-ring resonator has a major radius of 6μm （minor radius of 4.112μm） and a large free spectral range of 18 nm. Experimental results show a box-like channel dropping response, which has a 3 dB bandwidth of -2.7nm, high out-of-band signal rejection of around 40dB and a very low drop loss （〈0.5dB）. Simulation agrees well with the experiments. The footprint of the whole chip is only 0.0003mm2.
基金Supported by the National Natural Science Foundation of China under Grant Nos 60772023 and 60372095, the Key Project of the Ministry of Education of China under Grant No 106033, the Open Fund of the State Key Laboratory of Software Development Environment under Grant No SKLSDE-07-001, the National Key Basic Research Special Foundation of China under Grant No 2005CB321901, and the Specialized Research Fund for the Doctoral Programme of Higher Education of China under Grant No 20060006024.
文摘A variable-coemcient Kadomtsev-Petviashvili equation is investigated. The Painlev6 analysis leads to its explicit Painlevd-integrable conditions. An auto-Backlund transformation and the bilinear form are presented via the truncated Painlev6 expansion and symbolic computation. Several families of new analytic solutions arepresented, including the soliton-like and periodic solutions.
基金supported by the State Key Laboratory of Software Development Environment,China(Grant No.SKLSDE-2013ZX-21)the National Natural Science Foundation of China(Grant No.50971011)the Beijing Natural Science Foundation,China(Grant No.1102025)
文摘Ferromagnetism in the one-dimensional Hubbard model with the next-nearest-neighbor hopping is explored by using the exact-diagonalization method in a small cluster and the equation-of-motion method in the thermodynamic limit with electron density n = 3/2. With these two complementary methods, it is found that an intermediate value of the next-nearest- neighbor hopping amplitude tl tends to stabilize the fully polarized ferromagnetic state under the condition that the on-site coulomb interaction U is sufficiently large in our model. The ground-state phase diagram of the model is presented in the tl-U plane.
基金Supported by the National High Technology Research and Development Program of China under Grant No 2015AA016904the National Key Research and Development Plan of China under Grant No 2016YFB0402502the National Natural Science Foundation of China under Grant No 61275065
文摘A four-channel integrated optical wavelength de-multiplexer is experimentally illustrated on a silicon-on-insulator （SO1） substrate. With the aid of cascaded micro-ring resonators, the whole performance of the wavelength de- multiplexer is improved, such as 3 dB bandwidth and channel crosstalk. Based on the transform matrix theory, a four-channel wavelength de-multiplexer with average channel spacing 4.5±0.5 nm （3 dB bandwidth - 2 ± 0.5 nm） is demonstrated at telecommunication bands. For each channel, the extinction at the adjacent channel is below -39dB and the out-of-band rejection ratio is up to 40dB. The channel dropping loss is below 5dB in the five FSR spectral response periods （near 100 nm）.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11174022 and 11274195the NCET Program of MOE under Grant No NCET-11-0774+1 种基金the Fundamental Research Funds for the Central Universities,the National Basic Research Program of China under Grants No 2011CB606405the State Key Laboratory of Software Development Environment under Grant No SKLSDE-2013ZX-21.
文摘We propose a new scheme of realizing spin-polarized currents in a double quantum dot system.In the presence of Rashba spin-orbit coupling interactions and different Zeeman splittings of each quantum dot,the currents are spin-polarized.The polarization can be controlled by tuning the strength of Rashba spin-orbit coupling and external magnetic fields,which can produce nearly 100%spin-polarized currents.Furthermore,we explain and analyze the mechanism of the strongly spin-polarized currents.Lastly we give two phase diagrams to display our results.
文摘We study theoretically the plasmon excitations in a two-dimensional electron gas （2DEG） with spin-orbit interactions （SOIs） embedded in a （11n） crystallographic plane. We demonstrate that the energy spectra and dielectric functions between the 2DEGs embedded in different crystallographic planes can be related by a unitary transformation. Using the unitary transformation, we find that the anisotropy of plasmon excitations and the directional plasmon filtering （DPF） can be tuned by changing the strengths of SOIs in the high-index planes. There are two advantageous directions [110] and [nn2] for plasmon propagation. Moreover, the anisotropy and the DPF can be smeared out by tuning the strength ratio α/β between the Rashba SOI and the Dresselhaus SOI.
