In this paper, we investigate a two electronic level system with vibrational modes coupled to a Brownian oscillator bath. The difference frequency generation （DFG） signals and sum frequency generation （SFG） signal...In this paper, we investigate a two electronic level system with vibrational modes coupled to a Brownian oscillator bath. The difference frequency generation （DFG） signals and sum frequency generation （SFG） signals are calculated. It is shown that, for the same model, the SFG signals are more sensitive than the DFG signals to the changes of the vibrational modes of the electronic two-level system. Because the SFG conversion efficiency can be improved by using the time-delay method, the findings in this paper predict that the SFG spectrum may probe the changes of the microstructure more effectively.展开更多
The performance of a cellular location system based on received signal strength difference （RSSD） is investigated. In the cellular location system, each mobile station needs to measure the signal strength transmitte...The performance of a cellular location system based on received signal strength difference （RSSD） is investigated. In the cellular location system, each mobile station needs to measure the signal strength transmitted by surrounding base stations, and sends its measurements to the service base station. Using the strength difference between the service base station and neighboring base stations, the position of a mobile station is estimated. The related Cramer-Rao lower bound （CRLB） on the location error of this method was derived, and numerical simulations are made to discuss the influences of the number of base stations, correlation coefficient of shadowing attenuation, and cell radius on CRLB. The results show that the CRLB is positively correlated with the standard deviation of shadowing attenuation and cell radius, but negatively correlated with the number of base stations and the correlation coefficient of shadowing attenuation. In addition, the CRLB results obtained in this paper were compared with those of the cellular location system based on received signal strength （RSS） measurements, which reveals that the former is more tight.展开更多
Acute hemorrhagic anemia can decrease blood flow and oxygen supply to brain, and affect its physiological function. While detecting changes in brain function in patients with acute hemorrhagic anemia is helpful for pr...Acute hemorrhagic anemia can decrease blood flow and oxygen supply to brain, and affect its physiological function. While detecting changes in brain function in patients with acute hemorrhagic anemia is helpful for preventing neurological complications and evaluating therapeutic effects, clinical changes in the nervous systems of these patients have not received much attention. In part, this is because current techniques can only indirectly detect changes in brain function following onset of anemia, which leads to lags between real changes in brain function and their detection.展开更多
Topological insulating states in 2-dimensional(2D)materials are ideal systems to study different types of quantized response signals due to their in gap metallic states.Very recently,the quantum spin Hall effect was d...Topological insulating states in 2-dimensional(2D)materials are ideal systems to study different types of quantized response signals due to their in gap metallic states.Very recently,the quantum spin Hall effect was discovered in monolayer TalrTe Via the observation of quantized longitudinal conductance that rarely exists in other 2D topological insulators.The nontrivial Z_(2)topological charges can exist at both charge neutrality point and the van Hove singularity point with correlation-effect-induced bandgap.On the basis of this model 2D material,we studied the switch of quantized signals between longitudinal conductance and transversal Hall conductance via tuning external magnetic field.In Z_(2)topological phase of monolayer TalrTe_(4),the zero Chern number can be understood as 1-1=O from the double band inversion from spinup and spin-down channels.After applying a magnetic field perpendicular to the plane,the Zeeman split changes the band order for one branch of the band inversion from spin-up and spin-down channels,along with a sign charge of the Berry phase.Then,the net Chern number of 1-1=0 is tuned to 1+1=2 or-1-1=-2 depending on the orientation of the magnetic field.The quantized signal not only provides another effective method for the verification of topological state in monolayer TalrTe_(4)but also offers a strategy for the utilization of the new quantum topological states based on switchable quantized responses.展开更多
A 3.5 times PLL clock frequency multiplier for low voltage different signal （LVDS） driver is presented. A novel adaptive charge pump can automatically switch the loop bandwidth and a voltage-controlled oscillator （...A 3.5 times PLL clock frequency multiplier for low voltage different signal （LVDS） driver is presented. A novel adaptive charge pump can automatically switch the loop bandwidth and a voltage-controlled oscillator （VCO） is designed with the aid of frequency ranges reuse technology. The circuit is implemented using 1st Silicon 0.25 μm mixed-signal complementary metal-oxide-semiconductor （CMOS） process. Simulation results show that the PLL clock frequency multiplier has very low phase noise and very short capture time .展开更多
We compared efficiencies of different PMD compensation feedback methods against transmission signal bandwidth, including NRZ, RZ, CRZ format under various duty cycles. We found that the critical factor determining the...We compared efficiencies of different PMD compensation feedback methods against transmission signal bandwidth, including NRZ, RZ, CRZ format under various duty cycles. We found that the critical factor determining the efficiency of PMD compensation is not the modulation format, but the spectral bandwidth of the transmission signal.展开更多
基金Supported by the National Natural Science Foundation of China under Grant No. 61078065, Natural Science Foundation of Ningbo City under Grant No. 2008A61009, and K.C. Wong Magna Foundation in Ningbo University
文摘In this paper, we investigate a two electronic level system with vibrational modes coupled to a Brownian oscillator bath. The difference frequency generation （DFG） signals and sum frequency generation （SFG） signals are calculated. It is shown that, for the same model, the SFG signals are more sensitive than the DFG signals to the changes of the vibrational modes of the electronic two-level system. Because the SFG conversion efficiency can be improved by using the time-delay method, the findings in this paper predict that the SFG spectrum may probe the changes of the microstructure more effectively.
基金The National Natural Science Foundationof China (No.60472089)Southwest Jiaotong University Young Stuff Startup Research Project (No.2007Q134)
文摘The performance of a cellular location system based on received signal strength difference （RSSD） is investigated. In the cellular location system, each mobile station needs to measure the signal strength transmitted by surrounding base stations, and sends its measurements to the service base station. Using the strength difference between the service base station and neighboring base stations, the position of a mobile station is estimated. The related Cramer-Rao lower bound （CRLB） on the location error of this method was derived, and numerical simulations are made to discuss the influences of the number of base stations, correlation coefficient of shadowing attenuation, and cell radius on CRLB. The results show that the CRLB is positively correlated with the standard deviation of shadowing attenuation and cell radius, but negatively correlated with the number of base stations and the correlation coefficient of shadowing attenuation. In addition, the CRLB results obtained in this paper were compared with those of the cellular location system based on received signal strength （RSS） measurements, which reveals that the former is more tight.
基金supported by the Science and Technology Project of Shenzhen,No.JCY20120613170958482the First Affiliated Hospital of Shenzhen University Breeding Program,No.2012015
文摘Acute hemorrhagic anemia can decrease blood flow and oxygen supply to brain, and affect its physiological function. While detecting changes in brain function in patients with acute hemorrhagic anemia is helpful for preventing neurological complications and evaluating therapeutic effects, clinical changes in the nervous systems of these patients have not received much attention. In part, this is because current techniques can only indirectly detect changes in brain function following onset of anemia, which leads to lags between real changes in brain function and their detection.
基金supported by the Foundation from Liaoning Province(grant no.XLYC2203080)the National Natural Science Foundation of China(grant nos.52271016 and 52188101)the National Key R&D Program of China(grant no.2021YFB3501503)。
文摘Topological insulating states in 2-dimensional(2D)materials are ideal systems to study different types of quantized response signals due to their in gap metallic states.Very recently,the quantum spin Hall effect was discovered in monolayer TalrTe Via the observation of quantized longitudinal conductance that rarely exists in other 2D topological insulators.The nontrivial Z_(2)topological charges can exist at both charge neutrality point and the van Hove singularity point with correlation-effect-induced bandgap.On the basis of this model 2D material,we studied the switch of quantized signals between longitudinal conductance and transversal Hall conductance via tuning external magnetic field.In Z_(2)topological phase of monolayer TalrTe_(4),the zero Chern number can be understood as 1-1=O from the double band inversion from spinup and spin-down channels.After applying a magnetic field perpendicular to the plane,the Zeeman split changes the band order for one branch of the band inversion from spin-up and spin-down channels,along with a sign charge of the Berry phase.Then,the net Chern number of 1-1=0 is tuned to 1+1=2 or-1-1=-2 depending on the orientation of the magnetic field.The quantized signal not only provides another effective method for the verification of topological state in monolayer TalrTe_(4)but also offers a strategy for the utilization of the new quantum topological states based on switchable quantized responses.
基金Supported by the National Key Pre-Research Project of China (413010701-3)
文摘A 3.5 times PLL clock frequency multiplier for low voltage different signal （LVDS） driver is presented. A novel adaptive charge pump can automatically switch the loop bandwidth and a voltage-controlled oscillator （VCO） is designed with the aid of frequency ranges reuse technology. The circuit is implemented using 1st Silicon 0.25 μm mixed-signal complementary metal-oxide-semiconductor （CMOS） process. Simulation results show that the PLL clock frequency multiplier has very low phase noise and very short capture time .
文摘We compared efficiencies of different PMD compensation feedback methods against transmission signal bandwidth, including NRZ, RZ, CRZ format under various duty cycles. We found that the critical factor determining the efficiency of PMD compensation is not the modulation format, but the spectral bandwidth of the transmission signal.
