As an important parameter in the single airborne passive locating system, the rate of phase difference change contains range information of the radio emitter. Taking single carrier sine pulse signals as an example, th...As an important parameter in the single airborne passive locating system, the rate of phase difference change contains range information of the radio emitter. Taking single carrier sine pulse signals as an example, this article illustrates the principle of passive location through measurement of rates of phase difference change and analyzes the structure of measurement errors. On the basis of the Cramér-Rao lower bound (CRLB), an algorithm associated with time-chips is proposed to determine the rates of pha...展开更多
In the process of microemulsion flooding,microemulsion phase state may be affected by the adsorption of core and the distribution of oil and water,and the upper phase,the middle phase or the lower phase microemulsion ...In the process of microemulsion flooding,microemulsion phase state may be affected by the adsorption of core and the distribution of oil and water,and the upper phase,the middle phase or the lower phase microemulsion will appear.Accurate description of microemulsion phase state and quantitative discrimination of equilibrium phase composition are of great theoretical value and research significance for the design of microemulsion flooding system and improving the recovery efficiency of microemulsion.Therefore,in this paper,microemulsion phase model is deeply studied.Aiming at the difficulty of solving the existing Hand model and the unknown parameters of the improved HLD-NAC model,we introduce the binodal curve range parameter D and the asymmetric migration degree parameter B,and establish a new phase behavior description method of the binodal curve,the two-phase plait point lines and the III-phase node line.Then the phase discrimination programming of microemulsion was carried out,and the change laws of phase number,phase type and mass fraction of equilibrium phases of any microemulsion system under different salinity were revealed.The results show that the simulation results of microemulsions accord with the salinity scanning law,and can accurately identify the complex microemulsion phase states.展开更多
Optical phase transfer via fiber optics is the most effective method for optical frequency standard comparison on the scale below thousands of kilometers.However,the monotonic phase discrimination range of conventiona...Optical phase transfer via fiber optics is the most effective method for optical frequency standard comparison on the scale below thousands of kilometers.However,the monotonic phase discrimination range of conventional optical phase-locked loops is limited,and link delays restrict the control bandwidth,which makes it a challenge to achieve a continuously reliable optical link.This paper presents an event-timing-based phase detection method that overcomes the monotonic phase discrimination range limitation of conventional phase-locked loops through dual-edge timestamp recording,achieving an optical phase measurement resolution on the order of 10 attoseconds.With such a technique,we established a 7-segment-cascaded optical link over 1402km of commercial fiber while sharing dense wavelength division multiplexing(DWDM)channels with live telecom traffic.The system maintained continuous operation for 11.7 days without phase cycle slips despite encountering 15 km aerial fiber noise up to 21000 rad^(2)·Hz^(−1)·km^(−1)at 1 Hz.Relative instabilities of the link are 3.7×10^(−15)at 1 s and 3.9×10^(−20)at 100000 s.展开更多
The measurement of two-phase velocities in bubble flows using laser Doppler velocimetry(LDV)is studied.The key to the problem is to differentiate the LDV signals from bubbles and tracers,based on which the two-phase v...The measurement of two-phase velocities in bubble flows using laser Doppler velocimetry(LDV)is studied.The key to the problem is to differentiate the LDV signals from bubbles and tracers,based on which the two-phase velocities can be characterized.In this study,two experiments are carried out.Firstly,the bubble-chain experiment is performed to investigate the optical response of bubble surface and the corresponding LDV signal.The optical response shows that the light received by the LDV detector is dominated by the reflection component,which is similar to specular reflection to some extent.There are three typical patterns of signals of large bubbles passing through the measurement volume,all of which are with high amplitude and saturated.Then,the upward-flow experiment is conducted to study the statistical characteristics of large bubbles as well as micro tracers and micro bubbles.The results show that the amplitude of signal of millimeter bubbles is about an order of magnitude larger than that of tracers or micro bubbles.Based on this significant difference of the amplitude,we propose a phase discrimination method to distinguish two-phase signals.The capability of the proposed method is tested in a complex bubble flow,and its reliability is verified by bubble tracking velocimetry(BTV)technology.展开更多
基金Aeronautical Science Foundation of China (2007ZC53030)
文摘As an important parameter in the single airborne passive locating system, the rate of phase difference change contains range information of the radio emitter. Taking single carrier sine pulse signals as an example, this article illustrates the principle of passive location through measurement of rates of phase difference change and analyzes the structure of measurement errors. On the basis of the Cramér-Rao lower bound (CRLB), an algorithm associated with time-chips is proposed to determine the rates of pha...
基金financially supported by Northeast Petroleum University Talent Introduction Scientific Research Start-Up Foundation Project“dynamic characterization and prediction method of phase behavior of microemulsion flooding”National Natural Science Foundation of China under grant No.12002083Nature Science Foundation of Heilongjiang Province(LH2020E013)
文摘In the process of microemulsion flooding,microemulsion phase state may be affected by the adsorption of core and the distribution of oil and water,and the upper phase,the middle phase or the lower phase microemulsion will appear.Accurate description of microemulsion phase state and quantitative discrimination of equilibrium phase composition are of great theoretical value and research significance for the design of microemulsion flooding system and improving the recovery efficiency of microemulsion.Therefore,in this paper,microemulsion phase model is deeply studied.Aiming at the difficulty of solving the existing Hand model and the unknown parameters of the improved HLD-NAC model,we introduce the binodal curve range parameter D and the asymmetric migration degree parameter B,and establish a new phase behavior description method of the binodal curve,the two-phase plait point lines and the III-phase node line.Then the phase discrimination programming of microemulsion was carried out,and the change laws of phase number,phase type and mass fraction of equilibrium phases of any microemulsion system under different salinity were revealed.The results show that the simulation results of microemulsions accord with the salinity scanning law,and can accurately identify the complex microemulsion phase states.
基金supported by the National Key Research and Development Program of China(Grant No.2020YFC2200103)the Shandong Provincial Natural Science Foundation(Grant Nos.ZR2022LLZ006 and ZR2022LLZ011)+1 种基金the Innovation Program for Quantum Science and Technology(Grant Nos.2021ZD0300904 and 2021ZD0300903)the Key R&D Plan of Shandong Province(Grant No.2023CXPT105)。
文摘Optical phase transfer via fiber optics is the most effective method for optical frequency standard comparison on the scale below thousands of kilometers.However,the monotonic phase discrimination range of conventional optical phase-locked loops is limited,and link delays restrict the control bandwidth,which makes it a challenge to achieve a continuously reliable optical link.This paper presents an event-timing-based phase detection method that overcomes the monotonic phase discrimination range limitation of conventional phase-locked loops through dual-edge timestamp recording,achieving an optical phase measurement resolution on the order of 10 attoseconds.With such a technique,we established a 7-segment-cascaded optical link over 1402km of commercial fiber while sharing dense wavelength division multiplexing(DWDM)channels with live telecom traffic.The system maintained continuous operation for 11.7 days without phase cycle slips despite encountering 15 km aerial fiber noise up to 21000 rad^(2)·Hz^(−1)·km^(−1)at 1 Hz.Relative instabilities of the link are 3.7×10^(−15)at 1 s and 3.9×10^(−20)at 100000 s.
基金Project supported by the State Key Program of National Natural Science of China(Grant No.91852204)supported by the Program of State Key Laboratory of Marine Equipment(Grant No.SKLMEA-K201910).
文摘The measurement of two-phase velocities in bubble flows using laser Doppler velocimetry(LDV)is studied.The key to the problem is to differentiate the LDV signals from bubbles and tracers,based on which the two-phase velocities can be characterized.In this study,two experiments are carried out.Firstly,the bubble-chain experiment is performed to investigate the optical response of bubble surface and the corresponding LDV signal.The optical response shows that the light received by the LDV detector is dominated by the reflection component,which is similar to specular reflection to some extent.There are three typical patterns of signals of large bubbles passing through the measurement volume,all of which are with high amplitude and saturated.Then,the upward-flow experiment is conducted to study the statistical characteristics of large bubbles as well as micro tracers and micro bubbles.The results show that the amplitude of signal of millimeter bubbles is about an order of magnitude larger than that of tracers or micro bubbles.Based on this significant difference of the amplitude,we propose a phase discrimination method to distinguish two-phase signals.The capability of the proposed method is tested in a complex bubble flow,and its reliability is verified by bubble tracking velocimetry(BTV)technology.
