Nonlinear behaviors are investigated for a structure coupled with a nonlinear energy sink. The structure is linear and subject to a harmonic excitation, modeled as a forced single-degree-of-freedom oscillator. The non...Nonlinear behaviors are investigated for a structure coupled with a nonlinear energy sink. The structure is linear and subject to a harmonic excitation, modeled as a forced single-degree-of-freedom oscillator. The nonlinear energy sink is modeled as an oscillator consisting of a mass,a nonlinear spring, and a linear damper. Based on the numerical solutions, global bifurcation diagrams are presented to reveal the coexistence of periodic and chaotic motions for varying nonlinear energy sink mass and stiffness. Chaos is numerically identified via phase trajectories, power spectra,and Poincaré maps. Amplitude-frequency response curves are predicted by the method of harmonic balance for periodic steady-state responses. Their stabilities are analyzed.The Hopf bifurcation and the saddle-node bifurcation are determined. The investigation demonstrates that a nonlinear energy sink may create dynamic complexity.展开更多
Point-of-interest(POI) recommendation is a popular topic on location-based social networks(LBSNs).Geographical proximity,known as a unique feature of LBSNs,significantly affects user check-in behavior.However,most of ...Point-of-interest(POI) recommendation is a popular topic on location-based social networks(LBSNs).Geographical proximity,known as a unique feature of LBSNs,significantly affects user check-in behavior.However,most of prior studies characterize the geographical influence based on a universal or personalized distribution of geographic distance,leading to unsatisfactory recommendation results.In this paper,the personalized geographical influence in a two-dimensional geographical space is modeled using the data field method,and we propose a semi-supervised probabilistic model based on a factor graph model to integrate different factors such as the geographical influence.Moreover,a distributed learning algorithm is used to scale up our method to large-scale data sets.Experimental results based on the data sets from Foursquare and Gowalla show that our method outperforms other competing POI recommendation techniques.展开更多
Mathematical models for burden descending process have been applied to obtain whole burden structures in blast furnace,whereas the accuracy of those burden descent models has not been sufficiently investigated.Special...Mathematical models for burden descending process have been applied to obtain whole burden structures in blast furnace,whereas the accuracy of those burden descent models has not been sufficiently investigated.Special evaluation method based on timeline burden profiles was established to quantitatively evaluate the error between experimental and modeled burden structures.Four existing burden descent models were utilized to describe the burden structure of a 1/20 scaled warm blast furnace.Input modeling conditions including initial burden profile,descending volumes in each time interval,and normalized descending velocity distribution were determined via special image processing technology.Modeled burden structures were evaluated combined with the published experimental data.It is found that all the models caught the main profile of the burden structure.Furthermore,the improved nonuniform descent model（Model IV）shows the highest level of precision especially when burden descends with unstable velocity distribution tendency.Meanwhile,the traditional nonuniform descent model（Model III）may also be desirable to model the burden descending process when the burden descending velocity presents a linear tendency.Finally,the uniform descent model（Model I）might be the first option for roughly predicting burden structure.展开更多
A push-out test program was designed and conducted to study the meso-scale behavior of mortaraggregate interface for concrete after elevated temperatures ranging from 20℃ to 600℃ with the concept of modeled concrete...A push-out test program was designed and conducted to study the meso-scale behavior of mortaraggregate interface for concrete after elevated temperatures ranging from 20℃ to 600℃ with the concept of modeled concrete （MC） and modeled recycled aggregate concrete （MRAC）. The MCs and MRACs were designed with different strength grade of mortar and were exposed to different elevated temperatures. Following that the specimens were cooled to room temperature and push-out tests were conducted. Failure process and mechanical behaviors were analyzed based on failure modes, residual load-displacement curves, residual peak loads and peak displacements. It is found that failure modes significantly depended on specimen type, the elevated temperature and the strength grade of mortar. For MC, major cracks started to propagate along the initial cracks caused by elevated temperatures at about 80% of residual peak load. For MRAC, the cracks appeared at a lower level of load with the increasing elevated temperatures. The cracks connected with each other, formed a failure face and the specimens were split into several parts suddenly when reaching the residual peak load. Residual load-displacement curves of different specimens had similarities in shape. Besides, effect of temperatures and strength grade of mortar on residual peak load and peak displacement were analyzed. For MC and MRAC with higher strength of new hardened mortar, the residual peak load kept constant when the temperature is lower than 400℃ and dropped by 43.5% on average at 600℃. For MRAC with lower strength of new hardened mortar, the residual peak load began to reduce when the temperatures exceeded 200℃ and reduced by 27.4% and 60.8% respectively at 400℃ and 600℃. The properties of recycled aggregate concrete （RAC） may be more sensitive to elevated temperatures than those of natural aggregate concrete （NAC） due to the fact that the interracial properties of RAC are lower than those of NAC, and are deteriorated at lower temperatures.展开更多
The creep effect of suspensions in electro-dynamic loudspeakers was modeled based on fractional order derivatives.The fractional standard linear solid（FSLS） model was presented by substituting the Abel dashpot for N...The creep effect of suspensions in electro-dynamic loudspeakers was modeled based on fractional order derivatives.The fractional standard linear solid（FSLS） model was presented by substituting the Abel dashpot for Newton dashpot in Standard Linear Solid（SLS） model.The electrical impedance as well as the transfer function between diaphragm displacement and input voltage of the two tested midrange loudspeakers was measured by Klippel laser analyzer system,and the model parameters were identified by the least-mean-square method.By comparing the fitting results of FSLS model with the other two classical models- 4 Parameter Logarithmic model and SLS model,the results show that the FSLS model can rightly predict the frequency dependent compliance loss factor and yield higher accuracy for modeling the creep effect in loudspeaker suspensions.展开更多
Although the goal of traditional text summarization is to generate summaries with diverse information, most of those applications have no explicit definition of the information structure. Thus, it is difficult to gene...Although the goal of traditional text summarization is to generate summaries with diverse information, most of those applications have no explicit definition of the information structure. Thus, it is difficult to generate truly structure-aware summaries because the information structure to guide summarization is unclear. In this paper, we present a novel framework to generate guided summaries for product reviews. The guided summary has an explicitly defined structure which comes from the important aspects of products. The proposed framework attempts to maximize expected aspect satisfaction during summary generation. The importance of an aspect to a generated summary is modeled using Labeled Latent Dirichlet Allocation. Empirical experimental results on consumer reviews of cars show the effectiveness of our method.展开更多
A novel and accurate method is proposed to extract the intrinsic elements of the GaN high-electron-mobility transistor（HEMT） switch.The new extraction method is verified by comparing the simulated S-parameters with ...A novel and accurate method is proposed to extract the intrinsic elements of the GaN high-electron-mobility transistor（HEMT） switch.The new extraction method is verified by comparing the simulated S-parameters with the measured data over the 5-40 GHz frequency range.The percentage errors E（ij） within 3.83% show the great agreement between the simulated S-parameters and the measured data.展开更多
A lumped parameter-rigid elastic coupled dynamic model of two-stage planetary gears for a hybrid car is established through the inter-stage coupled method,in which the supports of the ring gear of planet set Ⅱ are re...A lumped parameter-rigid elastic coupled dynamic model of two-stage planetary gears for a hybrid car is established through the inter-stage coupled method,in which the supports of the ring gear of planet set Ⅱ are represented as an elastic foundation with radial and tangential uniform distributed stiffness,and the ring gear of planet set Ⅱ is modeled as an elastic continuum body. The natural frequencies based on the eigenvalue problem of dynamic model of planetary transmission are solved and the associated vibration modes are discussed. The rules are revealed which are the influences of the ring gear elastic supports stiffness and rim thickness on natural frequencies of planetary transmission. The theoretical analysis indicates that the vibration modes of planetary transmission with thin-walled ring gear on elastic supports are classified into seven types: Ⅰ/Ⅱ stage coupled rotational mode,Ⅰ stage translational mode,Ⅰ stage planet mode,Ⅱ stage translational mode,Ⅱ stage degenerate planet mode,Ⅱ stage distinct planet mode and purely ring gear mode. For each vibration mode, its properties are summarized. The numerical solutions show that the elastic supports stiffness and rim thickness of the ring gear of planet set Ⅱ have different influences on natural frequencies.展开更多
The differential cross section for an electron Raman scattering process in a semiconductor GaAs/AlGaAs double quantum well wire is calculated,and expressions for the electronic states are presented.The system is model...The differential cross section for an electron Raman scattering process in a semiconductor GaAs/AlGaAs double quantum well wire is calculated,and expressions for the electronic states are presented.The system is modeled by considering T = 0 K and also with a single parabolic conduction band,which is split into a subband system due to the confinement.The gain and differential cross-section for an electron Raman scattering process are obtained.In addition,the emission spectra for several scattering configurations are discussed,and interpretations of the singularities found in the spectra are given.The electron Raman scattering studied here can be used to provide direct information about the efficiency of the lasers.展开更多
The central dogma of molecular biology describes the flow of genetic information from DNA via RNA to protein and duplication from ancestral to descendent DNA（Crick,1958）.However,the genetic information could not be ...The central dogma of molecular biology describes the flow of genetic information from DNA via RNA to protein and duplication from ancestral to descendent DNA（Crick,1958）.However,the genetic information could not be quantified and mathematically modeled.So it differs from the“information”formulated by Shannon and used in information and coding theories（Shannon,1949）.展开更多
Muscles show a surprisingly large variety of functions when they mechanically respond to different environmental requests. However, the in vivo workloop studies distinguish well only four patterns of skeletal muscles,...Muscles show a surprisingly large variety of functions when they mechanically respond to different environmental requests. However, the in vivo workloop studies distinguish well only four patterns of skeletal muscles, producing positive, negative, almost zero and zero net works, that qualifies them respectively as motors, brakes, struts, and springs. While much effort of comparative biologists has been done in searching for muscle design patterns, no fundamental concepts underlying such four primary patterns were established. In this interdisciplinary study, continuum mechanics is applied to the problem of muscle structure in relation to function. The known ability of a powering muscle as whole to be tuned via natural (resonant) frequency to the efficient locomotion is now modeled through the non-linear elastic muscle moduli, controlling both the contraction frequency and velocity. When incorporated in activated skeletal and cardiac (striated) muscles via the mechanical similarity between loaded and reaction forces, further exploration of elastic force patterns (borrowed from solid state physics) yields an explicit rationalization for currently known locomotor muscle patterns. Besides explanation of the origin of allometric exponents derived for leg muscles in animals adapted to fast running and wing muscles in flying birds, the skeletal and cardiac muscles are patterned through the primary and secondary high power activities. Further applications are expected to be useful in designing of artificial muscles and modeling living and extinct animals.展开更多
Background： To our knowledge, there is little study on the interaction between nutrient availability and molecular structure changes induced by different processing methods in dairy cattle. The objective of this stud...Background： To our knowledge, there is little study on the interaction between nutrient availability and molecular structure changes induced by different processing methods in dairy cattle. The objective of this study was to investigate the effect of heat processing methods on interaction between nutrient availability and molecular structure in terms of functional groups that are related to protein and starch inherent structure of oat grains with two continued years and three replication of each year.Method： The oat grains were kept as raw（control） or heated in an air-draft oven（dry roasting： DO） at 120 °C for 60 min and under microwave irradiation（MIO） for 6 min. The molecular structure features were revealed by vibrational infrared molecular spectroscopy.Results： The results showed that rumen degradability of dry matter, protein and starch was significantly lower（P 〈0.05） for MIO compared to control and DO treatments. A higher protein α-helix to β-sheet and a lower amide I to starch area ratio were observed for MIO compared to DO and/or raw treatment. A negative correlation（-0.99, P 〈 0.01）was observed between α-helix or amide I to starch area ratio and dry matter. A positive correlation（0.99, P 〈 0.01） was found between protein β-sheet and crude protein.Conclusion： The results reveal that oat grains are more sensitive to microwave irradiation than dry heating in terms of protein and starch molecular profile and nutrient availability in ruminants.展开更多
We investigate the decoy state quantum key distribution via the atmosphere channels. We consider the efficient decoy state method with one-signal state and two-decoy states. Our results show that the decoy state metho...We investigate the decoy state quantum key distribution via the atmosphere channels. We consider the efficient decoy state method with one-signal state and two-decoy states. Our results show that the decoy state method works even in the channels with fluctuating transmittance. Nevertheless, the key generation rate will be dra-matically decreased by atmosphere turbulence, which sheds more light on the characterization of atmosphere turbulence in realistic free-space based quantum key distributions.展开更多
In this work, new plain and composite high-energy solitons of the cubic–quintic Swift–Hohenberg equation were numerically found. Starting from a composite pulse found by Soto-Crespo and Akhmediev and changing some p...In this work, new plain and composite high-energy solitons of the cubic–quintic Swift–Hohenberg equation were numerically found. Starting from a composite pulse found by Soto-Crespo and Akhmediev and changing some parameter values allowed us to find these high energy pulses. We also found the region in the parameter space in which these solutions exist. Some pulse characteristics, namely, temporal and spectral profiles and chirp, are presented. The study of the pulse energy shows its independence of the dispersion parameter but its dependence on the nonlinear gain. An extreme amplitude pulse has also been found.展开更多
Optical gains of type-Ⅱ In Ga As/Ga As Bi quantum wells（QWs） with W, N, and M shapes are analyzed theoretically for near-infrared laser applications. The bandgap and wave functions are calculated using the self-con...Optical gains of type-Ⅱ In Ga As/Ga As Bi quantum wells（QWs） with W, N, and M shapes are analyzed theoretically for near-infrared laser applications. The bandgap and wave functions are calculated using the self-consistent k·p Hamiltonian, taking into account valence band mixing and the strain effect. Our calculations show that the M-shaped type-Ⅱ QWs are a promising structure for making 1.3 um lasers at room temperature because they can easily be used to obtain 1.3 um for photoluminescence with a proper thickness and have large wave-function overlap for high optical gain.展开更多
基金supported by the National Natural Science Foundation of China (Grants 11402151 and 11572182)
文摘Nonlinear behaviors are investigated for a structure coupled with a nonlinear energy sink. The structure is linear and subject to a harmonic excitation, modeled as a forced single-degree-of-freedom oscillator. The nonlinear energy sink is modeled as an oscillator consisting of a mass,a nonlinear spring, and a linear damper. Based on the numerical solutions, global bifurcation diagrams are presented to reveal the coexistence of periodic and chaotic motions for varying nonlinear energy sink mass and stiffness. Chaos is numerically identified via phase trajectories, power spectra,and Poincaré maps. Amplitude-frequency response curves are predicted by the method of harmonic balance for periodic steady-state responses. Their stabilities are analyzed.The Hopf bifurcation and the saddle-node bifurcation are determined. The investigation demonstrates that a nonlinear energy sink may create dynamic complexity.
基金supported by National Key Basic Research Program of China(973 Program) under Grant No.2014CB340404National Natural Science Foundation of China under Grant Nos.61272111 and 61273216Youth Chenguang Project of Science and Technology of Wuhan City under Grant No. 2014070404010232
文摘Point-of-interest(POI) recommendation is a popular topic on location-based social networks(LBSNs).Geographical proximity,known as a unique feature of LBSNs,significantly affects user check-in behavior.However,most of prior studies characterize the geographical influence based on a universal or personalized distribution of geographic distance,leading to unsatisfactory recommendation results.In this paper,the personalized geographical influence in a two-dimensional geographical space is modeled using the data field method,and we propose a semi-supervised probabilistic model based on a factor graph model to integrate different factors such as the geographical influence.Moreover,a distributed learning algorithm is used to scale up our method to large-scale data sets.Experimental results based on the data sets from Foursquare and Gowalla show that our method outperforms other competing POI recommendation techniques.
基金Item Sponsored by National Natural Science Foundation of China(61290325)
文摘Mathematical models for burden descending process have been applied to obtain whole burden structures in blast furnace,whereas the accuracy of those burden descent models has not been sufficiently investigated.Special evaluation method based on timeline burden profiles was established to quantitatively evaluate the error between experimental and modeled burden structures.Four existing burden descent models were utilized to describe the burden structure of a 1/20 scaled warm blast furnace.Input modeling conditions including initial burden profile,descending volumes in each time interval,and normalized descending velocity distribution were determined via special image processing technology.Modeled burden structures were evaluated combined with the published experimental data.It is found that all the models caught the main profile of the burden structure.Furthermore,the improved nonuniform descent model（Model IV）shows the highest level of precision especially when burden descends with unstable velocity distribution tendency.Meanwhile,the traditional nonuniform descent model（Model III）may also be desirable to model the burden descending process when the burden descending velocity presents a linear tendency.Finally,the uniform descent model（Model I）might be the first option for roughly predicting burden structure.
文摘A push-out test program was designed and conducted to study the meso-scale behavior of mortaraggregate interface for concrete after elevated temperatures ranging from 20℃ to 600℃ with the concept of modeled concrete （MC） and modeled recycled aggregate concrete （MRAC）. The MCs and MRACs were designed with different strength grade of mortar and were exposed to different elevated temperatures. Following that the specimens were cooled to room temperature and push-out tests were conducted. Failure process and mechanical behaviors were analyzed based on failure modes, residual load-displacement curves, residual peak loads and peak displacements. It is found that failure modes significantly depended on specimen type, the elevated temperature and the strength grade of mortar. For MC, major cracks started to propagate along the initial cracks caused by elevated temperatures at about 80% of residual peak load. For MRAC, the cracks appeared at a lower level of load with the increasing elevated temperatures. The cracks connected with each other, formed a failure face and the specimens were split into several parts suddenly when reaching the residual peak load. Residual load-displacement curves of different specimens had similarities in shape. Besides, effect of temperatures and strength grade of mortar on residual peak load and peak displacement were analyzed. For MC and MRAC with higher strength of new hardened mortar, the residual peak load kept constant when the temperature is lower than 400℃ and dropped by 43.5% on average at 600℃. For MRAC with lower strength of new hardened mortar, the residual peak load began to reduce when the temperatures exceeded 200℃ and reduced by 27.4% and 60.8% respectively at 400℃ and 600℃. The properties of recycled aggregate concrete （RAC） may be more sensitive to elevated temperatures than those of natural aggregate concrete （NAC） due to the fact that the interracial properties of RAC are lower than those of NAC, and are deteriorated at lower temperatures.
文摘The creep effect of suspensions in electro-dynamic loudspeakers was modeled based on fractional order derivatives.The fractional standard linear solid（FSLS） model was presented by substituting the Abel dashpot for Newton dashpot in Standard Linear Solid（SLS） model.The electrical impedance as well as the transfer function between diaphragm displacement and input voltage of the two tested midrange loudspeakers was measured by Klippel laser analyzer system,and the model parameters were identified by the least-mean-square method.By comparing the fitting results of FSLS model with the other two classical models- 4 Parameter Logarithmic model and SLS model,the results show that the FSLS model can rightly predict the frequency dependent compliance loss factor and yield higher accuracy for modeling the creep effect in loudspeaker suspensions.
基金supported by the National Natural Science Foundation of China under Grant Nos.60973104 and 60803075with the aid of a grant from the International Development Research Center,Ottawa,Canada IRCI Project
文摘Although the goal of traditional text summarization is to generate summaries with diverse information, most of those applications have no explicit definition of the information structure. Thus, it is difficult to generate truly structure-aware summaries because the information structure to guide summarization is unclear. In this paper, we present a novel framework to generate guided summaries for product reviews. The guided summary has an explicitly defined structure which comes from the important aspects of products. The proposed framework attempts to maximize expected aspect satisfaction during summary generation. The importance of an aspect to a generated summary is modeled using Labeled Latent Dirichlet Allocation. Empirical experimental results on consumer reviews of cars show the effectiveness of our method.
文摘A novel and accurate method is proposed to extract the intrinsic elements of the GaN high-electron-mobility transistor（HEMT） switch.The new extraction method is verified by comparing the simulated S-parameters with the measured data over the 5-40 GHz frequency range.The percentage errors E（ij） within 3.83% show the great agreement between the simulated S-parameters and the measured data.
基金Innovation Funded Project of Fujian Province,China(No.2015C0030)Natural Science Foundation of Guangdong Province,China(No.S2013020013855)
文摘A lumped parameter-rigid elastic coupled dynamic model of two-stage planetary gears for a hybrid car is established through the inter-stage coupled method,in which the supports of the ring gear of planet set Ⅱ are represented as an elastic foundation with radial and tangential uniform distributed stiffness,and the ring gear of planet set Ⅱ is modeled as an elastic continuum body. The natural frequencies based on the eigenvalue problem of dynamic model of planetary transmission are solved and the associated vibration modes are discussed. The rules are revealed which are the influences of the ring gear elastic supports stiffness and rim thickness on natural frequencies of planetary transmission. The theoretical analysis indicates that the vibration modes of planetary transmission with thin-walled ring gear on elastic supports are classified into seven types: Ⅰ/Ⅱ stage coupled rotational mode,Ⅰ stage translational mode,Ⅰ stage planet mode,Ⅱ stage translational mode,Ⅱ stage degenerate planet mode,Ⅱ stage distinct planet mode and purely ring gear mode. For each vibration mode, its properties are summarized. The numerical solutions show that the elastic supports stiffness and rim thickness of the ring gear of planet set Ⅱ have different influences on natural frequencies.
文摘The differential cross section for an electron Raman scattering process in a semiconductor GaAs/AlGaAs double quantum well wire is calculated,and expressions for the electronic states are presented.The system is modeled by considering T = 0 K and also with a single parabolic conduction band,which is split into a subband system due to the confinement.The gain and differential cross-section for an electron Raman scattering process are obtained.In addition,the emission spectra for several scattering configurations are discussed,and interpretations of the singularities found in the spectra are given.The electron Raman scattering studied here can be used to provide direct information about the efficiency of the lasers.
基金supported by the National Natural Science Foundation of China (31372222)the Key Research Project of the National Natural Science Foundation of China (91531302)
文摘The central dogma of molecular biology describes the flow of genetic information from DNA via RNA to protein and duplication from ancestral to descendent DNA（Crick,1958）.However,the genetic information could not be quantified and mathematically modeled.So it differs from the“information”formulated by Shannon and used in information and coding theories（Shannon,1949）.
文摘Muscles show a surprisingly large variety of functions when they mechanically respond to different environmental requests. However, the in vivo workloop studies distinguish well only four patterns of skeletal muscles, producing positive, negative, almost zero and zero net works, that qualifies them respectively as motors, brakes, struts, and springs. While much effort of comparative biologists has been done in searching for muscle design patterns, no fundamental concepts underlying such four primary patterns were established. In this interdisciplinary study, continuum mechanics is applied to the problem of muscle structure in relation to function. The known ability of a powering muscle as whole to be tuned via natural (resonant) frequency to the efficient locomotion is now modeled through the non-linear elastic muscle moduli, controlling both the contraction frequency and velocity. When incorporated in activated skeletal and cardiac (striated) muscles via the mechanical similarity between loaded and reaction forces, further exploration of elastic force patterns (borrowed from solid state physics) yields an explicit rationalization for currently known locomotor muscle patterns. Besides explanation of the origin of allometric exponents derived for leg muscles in animals adapted to fast running and wing muscles in flying birds, the skeletal and cardiac muscles are patterned through the primary and secondary high power activities. Further applications are expected to be useful in designing of artificial muscles and modeling living and extinct animals.
基金supported by grants from the Prairie Oat Grower Association(POGA)Natural Sciences and Engineering Research Council of Canada(NSERC-federal government)Ministry of Agriculture Strategic Research Chair(PY)Program
文摘Background： To our knowledge, there is little study on the interaction between nutrient availability and molecular structure changes induced by different processing methods in dairy cattle. The objective of this study was to investigate the effect of heat processing methods on interaction between nutrient availability and molecular structure in terms of functional groups that are related to protein and starch inherent structure of oat grains with two continued years and three replication of each year.Method： The oat grains were kept as raw（control） or heated in an air-draft oven（dry roasting： DO） at 120 °C for 60 min and under microwave irradiation（MIO） for 6 min. The molecular structure features were revealed by vibrational infrared molecular spectroscopy.Results： The results showed that rumen degradability of dry matter, protein and starch was significantly lower（P 〈0.05） for MIO compared to control and DO treatments. A higher protein α-helix to β-sheet and a lower amide I to starch area ratio were observed for MIO compared to DO and/or raw treatment. A negative correlation（-0.99, P 〈 0.01）was observed between α-helix or amide I to starch area ratio and dry matter. A positive correlation（0.99, P 〈 0.01） was found between protein β-sheet and crude protein.Conclusion： The results reveal that oat grains are more sensitive to microwave irradiation than dry heating in terms of protein and starch molecular profile and nutrient availability in ruminants.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11574400,U1304613,11204197,11204379 and 11074244the National Basic Research Program of China under Grant No 2011CBA00200the Doctor Foundation of the Ministry of Education of China under Grant No 20113402110059
文摘We investigate the decoy state quantum key distribution via the atmosphere channels. We consider the efficient decoy state method with one-signal state and two-decoy states. Our results show that the decoy state method works even in the channels with fluctuating transmittance. Nevertheless, the key generation rate will be dra-matically decreased by atmosphere turbulence, which sheds more light on the characterization of atmosphere turbulence in realistic free-space based quantum key distributions.
基金FCT(Fundacao para a Ciência e Tecnologia)for supporting this work through the Project UID/CTM/50025/2013
文摘In this work, new plain and composite high-energy solitons of the cubic–quintic Swift–Hohenberg equation were numerically found. Starting from a composite pulse found by Soto-Crespo and Akhmediev and changing some parameter values allowed us to find these high energy pulses. We also found the region in the parameter space in which these solutions exist. Some pulse characteristics, namely, temporal and spectral profiles and chirp, are presented. The study of the pulse energy shows its independence of the dispersion parameter but its dependence on the nonlinear gain. An extreme amplitude pulse has also been found.
基金Supported by the National Basic Research Program of China under Grant No 2014CB643902the Key Program of Natural Science Foundation of China under Grant No 61334004+3 种基金the National Natural Science Foundation of China under Grant No 61404152the Strategic Priority Research Program of the Chinese Academy of Sciences under Grant No XDA5-1the Foundation of National Laboratory for Infrared Physics,the Key Research Program of the Chinese Academy of Sciences under Grant No KGZDEW-804the Creative Research Group Project of Natural Science Foundation of China under Grant No 61321492
文摘Optical gains of type-Ⅱ In Ga As/Ga As Bi quantum wells（QWs） with W, N, and M shapes are analyzed theoretically for near-infrared laser applications. The bandgap and wave functions are calculated using the self-consistent k·p Hamiltonian, taking into account valence band mixing and the strain effect. Our calculations show that the M-shaped type-Ⅱ QWs are a promising structure for making 1.3 um lasers at room temperature because they can easily be used to obtain 1.3 um for photoluminescence with a proper thickness and have large wave-function overlap for high optical gain.
