Four kinds of Au nanorods（NRs）with different aspect ratios are designed to adjust the relationship between resonance energy level of longitudinal（L）and transverse（T）modes.During the femto-second Z-scan experimen...Four kinds of Au nanorods（NRs）with different aspect ratios are designed to adjust the relationship between resonance energy level of longitudinal（L）and transverse（T）modes.During the femto-second Z-scan experiments,huge saturable absorption phenomena are observed while the energy level T is located between one to two times of the energylevel L.This means that the energy may transfer between longitudinal and transverse energylevels in the same and/or different Au NRs.It effectively depresses the production of revised saturated absorption and increases the saturable absorption efficiency.This method is significant for the preparation of high-efficiency saturable absorption devices.展开更多
The four-level model of laser-induced collisional energy transfer （LICET） for the ion-ion collision system is established based on the time-dependent SchrSdinger equation for the electron dynamics, through which the...The four-level model of laser-induced collisional energy transfer （LICET） for the ion-ion collision system is established based on the time-dependent SchrSdinger equation for the electron dynamics, through which the equations of motion of the probability amplitudes and cross section of the collision system are obtained. Numerical calculations are performed for the Ca＋ Sr＋ system, with the results showing that the peak of the LICET spectrum appears at a resonant frequency of the transfer laser. The magnitude of the obtained collision cross section is in the order of 10-16 cm2, and is comparable to that obtained in atomic systems, which indicates the validity of the established four-level model.展开更多
It is important to select suitable parameters of a submerged entry nozzle （SEN） for optimizing the flow and temperature patterns in a mold. The effect of SEN design on the mould level stability, meniscus steel flow ...It is important to select suitable parameters of a submerged entry nozzle （SEN） for optimizing the flow and temperature patterns in a mold. The effect of SEN design on the mould level stability, meniscus steel flow velocity, and heat transfer of the mold of a medium thin slab caster was studied by means of 1：1 water modeling and industrial testing. The advantages of a 2-port SEN compared with a 3-port SEN are the following： more optimal flow patterns with a lower mold level fluctuation and a lower meniscus steel flow velocity; proper powder consumption without slag bears due to a reasonable liquid powder thickness. The argon flow rate can be reduced and the mold average heat flux and temperature near the edges of the copper plate are reduced. At a casting speed of 2.5 m·min^-1, the mold level fluctuation lies within ＋5 mm. In addition, soft cooling of the steel shell in the mold is realized, which is suitable for casting crack susceptible steel grades.展开更多
Register transfer level mapping (RTLM) algorithm for technology mapping at RT level is presented,which supports current design methodologies using high level design and design reuse.The mapping rules implement a sou...Register transfer level mapping (RTLM) algorithm for technology mapping at RT level is presented,which supports current design methodologies using high level design and design reuse.The mapping rules implement a source ALU using target ALU.The source ALUs and the target ALUs are all represented by the general ALUs and the mapping rules are applied in the algorithm.The mapping rules are described in a table fashion.The graph clustering algorithm is a branch and bound algorithm based on the graph formulation of the mapping algorithm.The mapping algorithm suits well mapping of regularly structured data path.Comparisons are made between the experimental results generated by 1 greedy algorithm and graphclustering algorithm,showing the feasibility of presented algorithm.展开更多
The effect of delay time on photoelectron spectra and state populations of a four-level ladder K2 molecule is investigated by a pump1–pump2–probe pulse via the time-dependent wave packet approach. The periodical mot...The effect of delay time on photoelectron spectra and state populations of a four-level ladder K2 molecule is investigated by a pump1–pump2–probe pulse via the time-dependent wave packet approach. The periodical motion of the wave packet leads to the periodical change of the photoelectron spectra. The Autler–Townes triple splitting appears at zero delay time, double splitting appears at nonzero delay time between pump1 and pump2 pulses, and no splitting appears at nonzero delay time between pump2 and probe pulses. The periodical change of the state populations with the delay time may be due to the coupling effect between the two pulses. It is found that the selectivity of the state populations may be attained by regulating the delay time. The results can provide an important basis for realizing the optical control of molecules experimentally.展开更多
By doping red dye 4 dicyanomethylene 2 ( tert butyl) 6 methyl 4H pyran(DCJTB) in the tris (8 hydroxyquinolinato) metal Mq 3(where M = Al, Ga, In) chelate complexes, a series of red dopant organic light ...By doping red dye 4 dicyanomethylene 2 ( tert butyl) 6 methyl 4H pyran(DCJTB) in the tris (8 hydroxyquinolinato) metal Mq 3(where M = Al, Ga, In) chelate complexes, a series of red dopant organic light emitting diodes with different doping concentrations have been fabricated. The electroluminescence efficiency of these red diodes with a DCJTB doped Mq 3 emitting layer is found to be decreased markedly with the increasing of doping concentration. Electroluminescence characteristics of these devices are studied in terms of energy levels matching of red dopant with the host materials and carrier transporting layers.展开更多
We discuss the dynamics of a three-level V-type atom driven simultaneously by a cavity photon and microwave field by examining the atomic population evolution. Owing to the coupling effect of the cavity photon, period...We discuss the dynamics of a three-level V-type atom driven simultaneously by a cavity photon and microwave field by examining the atomic population evolution. Owing to the coupling effect of the cavity photon, periodical oscillation of the population between the two upper states and the ground state takes place, which is the well-known vacuum Rabi oscillation. Meanwhile, the population exchange between the upmost level and the middle level can occur due to the driving action of the external microwave field. The general dynamic behavior is the superposition of a fast and a slow periodical oscillation under the cooperative and competitive effect of the cavity photon and the microwave field. Numerical results demonstrate that the time evolution of the population is strongly dependent on the atom-cavity coupling coefficient g and Rabi frequency Ωe that reflects the intensity of the external microwave field. By modulating the two parameters g and Ωe, a large number of population transfer behaviors can be achieved.展开更多
To evaluate the reliability of a landslide in a reservoir, the universal transfer coefficient method, which is popularized by the Chinese standard, is adopted as performance function in this study for： （1） common d...To evaluate the reliability of a landslide in a reservoir, the universal transfer coefficient method, which is popularized by the Chinese standard, is adopted as performance function in this study for： （1） common deterministic method stability evaluation; （2） reliability evaluation based on a Monte Carlo method; （3） comparison of landslide reliability under different water levels and under different correlation coefficients between soil shear strength parameters （c, Φ）, respectively with mean, standard deviation, reliability coefficient and failure probability. This article uses the Bazimen （八字门） landslide, which is located at the outlet of Xiangxi （香溪） River in the Three Gorges Reservoir, as an example to evaluate its stability and reliability under different water levels with two-dimensional deterministic and probabilistic methods. With the assumption that constant mean and normal distributed shear strength parameters （c, Φ）, correlation coefficient c, Φ=-1 based reliability analysis, compared with c, Φ=0 and 1, indicates obviously more increase of reliability index and lower standard deviation as water levels rise. To the case of a certain water level, c, Φ=-1 does not have constantly positive or negative effects on landslide reliability compared with c, Φ=0 or 1, but is associated with water level. Whereas the safety factor Fs by deterministic method, which is almost the same value as corresponding mean of safety factor from probabilistic analysis, will increase slightly as water level increases.展开更多
[ Objective] To extract non-specific transfer factors （TFs） from goose spleens and to detect the activity of the extracts. [Methodl The non-specific TFs were extracted crudely from goose spleens using the dialysis m...[ Objective] To extract non-specific transfer factors （TFs） from goose spleens and to detect the activity of the extracts. [Methodl The non-specific TFs were extracted crudely from goose spleens using the dialysis method, and the effects of the extracts on immunity were studied. [ Result] The extracts of goose TFs were transparent, light yellow and non-toxic. The extracts were at pH 6.72 and did not contain higher molecular weight proteins. The concentration of minor polypeptides was 23.78 ug/ml. The results of immunization test showed that the level of antibodies was higher in the geese inoculated with the inactivated vaccine against infections serositis and the extracts of TFs than in the control geese injected with normal saline. In addition, the level of antibodies was significantly higher in the geese only inoculated with inactivated vaccine than in the control geese. The results showed that the extracts of TFs from goose spleens could enhance immunity to a certain extent. [ Conclusion] The study pro- vides a theoretical basis and technical reference for further researches on the biological activity of non-specific TFs from goose spleens as well as for application of the extracts.展开更多
In this paper, a two level finite difference scheme of Crank-Nicholson type is constructed and used to numerically investigate nonlinear temperature distribution in biological tissues described by bioheat transfer equ...In this paper, a two level finite difference scheme of Crank-Nicholson type is constructed and used to numerically investigate nonlinear temperature distribution in biological tissues described by bioheat transfer equation of Pennes’ type. For the equation under consideration, the thermal conductivity is either depth-dependent or tem-perature-dependent, while blood perfusion is temperature-dependent. In both cases of depth- dependent and temperature-dependent thermal conductivity, it is shown that blood perfusion decreases the temperature of the living tissue. Our numerical simulations show that neither the localization nor the magnitude of peak tempera-ture is affected by surface temperature;however, the width of peak temperature increases with surface temperature.展开更多
The problem of optimal aeroassisted symmetric transfer between elliptical orbits is concerned.The complete trajectory is assumed as consisting of two impulsive velocity changes at the beginning and the end of an inter...The problem of optimal aeroassisted symmetric transfer between elliptical orbits is concerned.The complete trajectory is assumed as consisting of two impulsive velocity changes at the beginning and the end of an interior atmospheric subarc,where the vehicle is controlled via the lift coefficient and thrust.The corresponding dynamic equations are built and bounded controls are considered.For the purpose of optimization computation,the equations are normalized.In order to minimize the total fuel consumption,the geocentric radius of initial elliptical transfer orbital perigee and controls during atmospheric flight should all be optimized.It is an optimal control problem which involves additional parameter optimization.To solve the problem,a two-level optimization method denoted by ＂genetic algorithm ＋ Gauss pseudospectral method＂ is adopted：the genetic algorithm is used for parameter optimization and the Gauss pseudospectral method is used for optimal control problems.The flow chart of simulation is given.On this basis,the issue of more realistic modeling with two finite-thrust subarcs in the nonatmospheric part of the trajectory is simultaneously addressed.The orbital transfer problem is transformed to three continuous optimal control problems,and the constraints at different times are given,which are respectively solved by using the Gauss pseudospectral method.The obtained numerical results indicate that the optimal thrust control is of bangbang type.The minimum-fuel trajectory in the atmosphere consists of aeroglide,aerocruise and aeroglide.They are compared with the results of pure impulsive model,and the conclusions that a significant fuel saving will be achieved by synergetic maneuver are drawn.展开更多
In this paper, we focus on the design of irregular QC-LDPC code based multi-level coded modulation(MLCM) scheme by jointly optimizing the component code rate and the degree distribution of the irregular QC-LDPC compon...In this paper, we focus on the design of irregular QC-LDPC code based multi-level coded modulation(MLCM) scheme by jointly optimizing the component code rate and the degree distribution of the irregular QC-LDPC component code. Firstly, the sub-channel capacities of MLCM systems is analyzed and discussed, based on which the optimal component code rate can be obtained. Secondly, an extrinsic information transfer chart based two-stage searching algorithm is proposed to find the good irregular QC-LDPC code ensembles with optimal component code rates for their corresponding sub-channels. Finally, by constructing the irregular QC-LDPC component codes from the designed ensembles with the aim of possibly enlarging the girth and reducing the number of the shortest cycles, the designed irregular QC-LDPC code based 16QAM and 64QAM MLCM systems can achieve 0.4 dB and 1.2 dB net coding gain, respectively, compared with the recently proposed regular QC-LDPC code based 16QAM and 64QAM MLCM systems.展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos 11404410 and 11504105the Hunan Provincial Natural Science Foundation under Grant No 2016JJ3140
文摘Four kinds of Au nanorods（NRs）with different aspect ratios are designed to adjust the relationship between resonance energy level of longitudinal（L）and transverse（T）modes.During the femto-second Z-scan experiments,huge saturable absorption phenomena are observed while the energy level T is located between one to two times of the energylevel L.This means that the energy may transfer between longitudinal and transverse energylevels in the same and/or different Au NRs.It effectively depresses the production of revised saturated absorption and increases the saturable absorption efficiency.This method is significant for the preparation of high-efficiency saturable absorption devices.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 10674036 and 10774033)Program of Excellent Team in Harbin Institute of Technology,China
文摘The four-level model of laser-induced collisional energy transfer （LICET） for the ion-ion collision system is established based on the time-dependent SchrSdinger equation for the electron dynamics, through which the equations of motion of the probability amplitudes and cross section of the collision system are obtained. Numerical calculations are performed for the Ca＋ Sr＋ system, with the results showing that the peak of the LICET spectrum appears at a resonant frequency of the transfer laser. The magnitude of the obtained collision cross section is in the order of 10-16 cm2, and is comparable to that obtained in atomic systems, which indicates the validity of the established four-level model.
文摘It is important to select suitable parameters of a submerged entry nozzle （SEN） for optimizing the flow and temperature patterns in a mold. The effect of SEN design on the mould level stability, meniscus steel flow velocity, and heat transfer of the mold of a medium thin slab caster was studied by means of 1：1 water modeling and industrial testing. The advantages of a 2-port SEN compared with a 3-port SEN are the following： more optimal flow patterns with a lower mold level fluctuation and a lower meniscus steel flow velocity; proper powder consumption without slag bears due to a reasonable liquid powder thickness. The argon flow rate can be reduced and the mold average heat flux and temperature near the edges of the copper plate are reduced. At a casting speed of 2.5 m·min^-1, the mold level fluctuation lies within ＋5 mm. In addition, soft cooling of the steel shell in the mold is realized, which is suitable for casting crack susceptible steel grades.
文摘Register transfer level mapping (RTLM) algorithm for technology mapping at RT level is presented,which supports current design methodologies using high level design and design reuse.The mapping rules implement a source ALU using target ALU.The source ALUs and the target ALUs are all represented by the general ALUs and the mapping rules are applied in the algorithm.The mapping rules are described in a table fashion.The graph clustering algorithm is a branch and bound algorithm based on the graph formulation of the mapping algorithm.The mapping algorithm suits well mapping of regularly structured data path.Comparisons are made between the experimental results generated by 1 greedy algorithm and graphclustering algorithm,showing the feasibility of presented algorithm.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11704178 and 11764041)the Scientific Research Fund of Hunan Provincial Education Department,China(Grant No.15B204)
文摘The effect of delay time on photoelectron spectra and state populations of a four-level ladder K2 molecule is investigated by a pump1–pump2–probe pulse via the time-dependent wave packet approach. The periodical motion of the wave packet leads to the periodical change of the photoelectron spectra. The Autler–Townes triple splitting appears at zero delay time, double splitting appears at nonzero delay time between pump1 and pump2 pulses, and no splitting appears at nonzero delay time between pump2 and probe pulses. The periodical change of the state populations with the delay time may be due to the coupling effect between the two pulses. It is found that the selectivity of the state populations may be attained by regulating the delay time. The results can provide an important basis for realizing the optical control of molecules experimentally.
文摘By doping red dye 4 dicyanomethylene 2 ( tert butyl) 6 methyl 4H pyran(DCJTB) in the tris (8 hydroxyquinolinato) metal Mq 3(where M = Al, Ga, In) chelate complexes, a series of red dopant organic light emitting diodes with different doping concentrations have been fabricated. The electroluminescence efficiency of these red diodes with a DCJTB doped Mq 3 emitting layer is found to be decreased markedly with the increasing of doping concentration. Electroluminescence characteristics of these devices are studied in terms of energy levels matching of red dopant with the host materials and carrier transporting layers.
基金supported by the National Natural Science Foundation of China(Grant Nos.11434017 and 11374357)the National Basics Research Program of China(Grant No.2013CB632704)
文摘We discuss the dynamics of a three-level V-type atom driven simultaneously by a cavity photon and microwave field by examining the atomic population evolution. Owing to the coupling effect of the cavity photon, periodical oscillation of the population between the two upper states and the ground state takes place, which is the well-known vacuum Rabi oscillation. Meanwhile, the population exchange between the upmost level and the middle level can occur due to the driving action of the external microwave field. The general dynamic behavior is the superposition of a fast and a slow periodical oscillation under the cooperative and competitive effect of the cavity photon and the microwave field. Numerical results demonstrate that the time evolution of the population is strongly dependent on the atom-cavity coupling coefficient g and Rabi frequency Ωe that reflects the intensity of the external microwave field. By modulating the two parameters g and Ωe, a large number of population transfer behaviors can be achieved.
基金supported by the German Federal Ministry of Education and Research (BMBF)
文摘To evaluate the reliability of a landslide in a reservoir, the universal transfer coefficient method, which is popularized by the Chinese standard, is adopted as performance function in this study for： （1） common deterministic method stability evaluation; （2） reliability evaluation based on a Monte Carlo method; （3） comparison of landslide reliability under different water levels and under different correlation coefficients between soil shear strength parameters （c, Φ）, respectively with mean, standard deviation, reliability coefficient and failure probability. This article uses the Bazimen （八字门） landslide, which is located at the outlet of Xiangxi （香溪） River in the Three Gorges Reservoir, as an example to evaluate its stability and reliability under different water levels with two-dimensional deterministic and probabilistic methods. With the assumption that constant mean and normal distributed shear strength parameters （c, Φ）, correlation coefficient c, Φ=-1 based reliability analysis, compared with c, Φ=0 and 1, indicates obviously more increase of reliability index and lower standard deviation as water levels rise. To the case of a certain water level, c, Φ=-1 does not have constantly positive or negative effects on landslide reliability compared with c, Φ=0 or 1, but is associated with water level. Whereas the safety factor Fs by deterministic method, which is almost the same value as corresponding mean of safety factor from probabilistic analysis, will increase slightly as water level increases.
基金funded by the Innovation Fund Project for College Students of Rongchang Campus of Southwest University,Chongqing Basic Research program ( 2008BB5243)the Fundamental Research Funds for the Central Universities( XDJK2010C093)
文摘[ Objective] To extract non-specific transfer factors （TFs） from goose spleens and to detect the activity of the extracts. [Methodl The non-specific TFs were extracted crudely from goose spleens using the dialysis method, and the effects of the extracts on immunity were studied. [ Result] The extracts of goose TFs were transparent, light yellow and non-toxic. The extracts were at pH 6.72 and did not contain higher molecular weight proteins. The concentration of minor polypeptides was 23.78 ug/ml. The results of immunization test showed that the level of antibodies was higher in the geese inoculated with the inactivated vaccine against infections serositis and the extracts of TFs than in the control geese injected with normal saline. In addition, the level of antibodies was significantly higher in the geese only inoculated with inactivated vaccine than in the control geese. The results showed that the extracts of TFs from goose spleens could enhance immunity to a certain extent. [ Conclusion] The study pro- vides a theoretical basis and technical reference for further researches on the biological activity of non-specific TFs from goose spleens as well as for application of the extracts.
文摘In this paper, a two level finite difference scheme of Crank-Nicholson type is constructed and used to numerically investigate nonlinear temperature distribution in biological tissues described by bioheat transfer equation of Pennes’ type. For the equation under consideration, the thermal conductivity is either depth-dependent or tem-perature-dependent, while blood perfusion is temperature-dependent. In both cases of depth- dependent and temperature-dependent thermal conductivity, it is shown that blood perfusion decreases the temperature of the living tissue. Our numerical simulations show that neither the localization nor the magnitude of peak tempera-ture is affected by surface temperature;however, the width of peak temperature increases with surface temperature.
基金supported by the National High Technology Research and Development Program of China(863Program)(2011AA0469)
文摘The problem of optimal aeroassisted symmetric transfer between elliptical orbits is concerned.The complete trajectory is assumed as consisting of two impulsive velocity changes at the beginning and the end of an interior atmospheric subarc,where the vehicle is controlled via the lift coefficient and thrust.The corresponding dynamic equations are built and bounded controls are considered.For the purpose of optimization computation,the equations are normalized.In order to minimize the total fuel consumption,the geocentric radius of initial elliptical transfer orbital perigee and controls during atmospheric flight should all be optimized.It is an optimal control problem which involves additional parameter optimization.To solve the problem,a two-level optimization method denoted by ＂genetic algorithm ＋ Gauss pseudospectral method＂ is adopted：the genetic algorithm is used for parameter optimization and the Gauss pseudospectral method is used for optimal control problems.The flow chart of simulation is given.On this basis,the issue of more realistic modeling with two finite-thrust subarcs in the nonatmospheric part of the trajectory is simultaneously addressed.The orbital transfer problem is transformed to three continuous optimal control problems,and the constraints at different times are given,which are respectively solved by using the Gauss pseudospectral method.The obtained numerical results indicate that the optimal thrust control is of bangbang type.The minimum-fuel trajectory in the atmosphere consists of aeroglide,aerocruise and aeroglide.They are compared with the results of pure impulsive model,and the conclusions that a significant fuel saving will be achieved by synergetic maneuver are drawn.
基金supported by National Natural Science Foundation of China(No.61571061)
文摘In this paper, we focus on the design of irregular QC-LDPC code based multi-level coded modulation(MLCM) scheme by jointly optimizing the component code rate and the degree distribution of the irregular QC-LDPC component code. Firstly, the sub-channel capacities of MLCM systems is analyzed and discussed, based on which the optimal component code rate can be obtained. Secondly, an extrinsic information transfer chart based two-stage searching algorithm is proposed to find the good irregular QC-LDPC code ensembles with optimal component code rates for their corresponding sub-channels. Finally, by constructing the irregular QC-LDPC component codes from the designed ensembles with the aim of possibly enlarging the girth and reducing the number of the shortest cycles, the designed irregular QC-LDPC code based 16QAM and 64QAM MLCM systems can achieve 0.4 dB and 1.2 dB net coding gain, respectively, compared with the recently proposed regular QC-LDPC code based 16QAM and 64QAM MLCM systems.
