We present a theoretical scheme for broadband multi-channel quantum noise suppression and phase-sensitive modulation of continuous variables in a coupled resonant system with quantum entanglement properties.The effect...We present a theoretical scheme for broadband multi-channel quantum noise suppression and phase-sensitive modulation of continuous variables in a coupled resonant system with quantum entanglement properties.The effects of different coupling strengths,pumping power in suppressing quantum noise and controlling the width of quantum interference channels are analyzed carefully.Furthermore,quantum noise suppression at quadrature amplitude is obtained with phase-sensitive modulation.It shows that the entanglement strength of the output field and the quantum noise suppression effect can be enhanced significantly by a strong pumping filed due to interaction of pumping light with the nonlinear crystal.The full width at half maxima(FWHM)of the noise curve at the resonant peak(△=0 MHz)is broadened up to 2.17 times compared to the single cavity.In the strong coupling resonant system,the FWHM at △=0 MHz(△=±3.1 MHz)is also broadened up to 1.27(3.53)times compared to the weak coupling resonant system case.The multi-channel quantum interference creates an electromagnetically induced transparent-like line shape,which can be used to improve the transmission efficiency and stability of wave packets in quantum information processing and quantum memory.展开更多
提出基于布里渊光时域反射(Brillouin optic time domain reflectometer,BOTDR)分布式检测技术与解调信号的光缆隐蔽性缺陷识别方法,识别检测光缆隐蔽性缺陷。在生产阶段将光纤植入多股碳纤维导线复合芯内部作为传感器,依据BOTDR技术与...提出基于布里渊光时域反射(Brillouin optic time domain reflectometer,BOTDR)分布式检测技术与解调信号的光缆隐蔽性缺陷识别方法,识别检测光缆隐蔽性缺陷。在生产阶段将光纤植入多股碳纤维导线复合芯内部作为传感器,依据BOTDR技术与光时域反射(optic time domain reflectometer,OTDR)技术原理,构建关于碳纤维导线光缆隐蔽性检测的分布式传感系统,利用光纤对温度、应力、传播损耗的高精度感知,多维度地分析碳纤维导线光缆的隐蔽性缺陷及位置分布,实现光缆的隐蔽性缺陷识别。利用morlet小波解调布里渊散射信号,提取包络信息,去除信号噪声,采用列文伯格-马夸尔特算法,拟合布里渊散射谱数据,精确估计最优Brillouin频移量参数,提升整体缺陷识别精度。实验证明:该方法可以准确地对光缆的隐蔽性缺陷进行表征,实现多股碳纤维导线光缆隐蔽性缺陷的快速、有效识别,促进碳纤维导线光缆更好地应用于增容、大跨越等工程中。展开更多
Robust and fast fat suppression is a challenge in balanced steady-state free precession （SSFP） magnetic resonance imaging. Although single-acquisition phase-sensitive SSFP can provide fat-suppressed images in short ...Robust and fast fat suppression is a challenge in balanced steady-state free precession （SSFP） magnetic resonance imaging. Although single-acquisition phase-sensitive SSFP can provide fat-suppressed images in short scan time, phase errors, especially spatially-dependent phase shift, caused by a variety of factors may result in misplacement of fat and water voxels. In this paper, a novel phase correction algorithm was used to calibrate those phase errors during image reconstruction. This algorithm corrects phase by region growing, employing both the magnitude and the phase information of image pixels. Phantom and in vivo imagings were performed to validate the technique. As a result, excellent fat-suppressed images were acquired by using single-acquisition phase-sensitive SSFP with phase correction.展开更多
Objective:Late gadolinium enhancement(LGE) patterns of cardiovascular magnetic resonance (CMR) relying on PSIR(phase-sensitive inversion recovery sequence) techniques had been used to determine the characteristics of ...Objective:Late gadolinium enhancement(LGE) patterns of cardiovascular magnetic resonance (CMR) relying on PSIR(phase-sensitive inversion recovery sequence) techniques had been used to determine the characteristics of LGE in apical hypertrophic cardiomyopathy(ApHCM). Methods:Forty patients pure ApHCM[age,(60.2±10.4) years,31 men]were enrolled.LGE images were acquired using PSIR,and analyzed using a 17-segment model.Summing the LGE areas in all short axis slices yielded the total volume of late enhancement,which was subsequently presented as a proportion of total LV myocardium(%LGE).Results:Mean maximal apical wall thickness was(17.9±2.3) mm,and mean left ventricular(LV) ejection fraction was(67.7±8.0)%.LGE was detected in 130 segments of 30 patients(75.0%),occupying(4.9±5.5)% of LV myocardium.LGE was mainly detected at the junction between left and right ventricles in 12(30%) and at the apex in 28(70%),although LGE-positive areas were widely distributed,and not limited to the apex.Focal LGE at the non-hypertrophic LV segments was found in some ApHCM patients,even without LGE of hypertrophied apical segments.Conclusions:LGE was frequently observed not only in the thickened apex of the heart but also in other LV segments,irrespective of the presence or absence of hypertrophy.The simple presence of LGE on CMR was not representative of adverse prognosis in this population.展开更多
A phase-sensitive optical time domain reflectometer （φ-OTDR） based on a 120°-phase-difference Michelson in- terferometer is proposed. The Michelson interferometer with arm difference of 4m is used to test the ...A phase-sensitive optical time domain reflectometer （φ-OTDR） based on a 120°-phase-difference Michelson in- terferometer is proposed. The Michelson interferometer with arm difference of 4m is used to test the phase difference between the Rayleigh scattering from two sections of the fiber. A new demodulation method called the inverse transmission matrix demodulation scheme is utilized to demodulate the distributed phase from the backward scattering along the long fiber, The experimental results show that the 120°-phase-difference inter- ferometer φ-OTDR can detect the phase along the 3km fiber, and the acoustic signal within the whole human hearing range of 20 Hz-20 kHz is reproduced accurately and quickly.展开更多
Objective:To determine the deference between phase sensitive magnetic resonance(MR) imaging and magnitude reconstruction to detect infracted myocardium.Methods:Twenty patients(16 men;4 women;mean age,56 years),experie...Objective:To determine the deference between phase sensitive magnetic resonance(MR) imaging and magnitude reconstruction to detect infracted myocardium.Methods:Twenty patients(16 men;4 women;mean age,56 years),experienced Q-wave myocardial infarction 2 weeks earlier were examined with a 3.0-T MR system 10 minutes after administration of 0.1 mmol/kg body weight gadobenate dimeglumine.To determine the optimal TI,a TI scout sequence was used.A segmented 2D IR true fast imaging with steady-state precession(trueFISP) sequence that produces both phase-sensitive and magnitude-reconstructed images were used at TI values of 200-600 msec(TI values were varied in 100-msec steps) and at optimal TI(mean value,330 msec).Contrast- noise ratios(CNRs) of normal and infarcted myocardium and the area of infarcted myocardium were determined.Two-tailed unpaired sample Student t test was used to compare CNRs,and area of infarction.Results:MMean CNR phase-sensitive and magnitude-reconstructed images at optimal TI(mean value,330 msec) were 6.2,and 6.1,respectively.For a TI of 200 msec,CNR values were 5.5,and 4.2,respectively;for TI of 600 msec,CNR values were 5.8 and 4.3,respectively.Area of infarcted myocardium was underestimated on magnitude-reconstruction images(P = 0.002-0.03) for short TI values(ie.,200 msec) but not on phase sensitive reconstructed when compared with IR tureFISP images obtained at optimal TI.Conclusions: LPhase-sensitive image reconstruction results in reduced need for precise choice of TI and more consistent image quality.展开更多
We study the colour-locked twin-noisy-field correlation effects in the fifth-order nonlinear susceptibility of ultrafast polarization beats in a cascade four-level system. More importantly, the fifth-order phase-sensi...We study the colour-locked twin-noisy-field correlation effects in the fifth-order nonlinear susceptibility of ultrafast polarization beats in a cascade four-level system. More importantly, the fifth-order phase-sensitive heterodyne detection of ultrafast polarization beats has been exploited. The fifth-order nonlinear optical response can be controlled and modified through the colour-locked correlation of twin noisy fields. Thus, this method with the phase dispersion information is a good way to measure the real and imaginary parts of the fifth-order nonlinear susceptibility.展开更多
基金Project supported by National Natural Science Foundation of China(Grant Nos.11704053 and 52175531)the Science and Technology Research Program of Chongqing Municipal Education Commission(Grant No.KJQN201800629)。
文摘We present a theoretical scheme for broadband multi-channel quantum noise suppression and phase-sensitive modulation of continuous variables in a coupled resonant system with quantum entanglement properties.The effects of different coupling strengths,pumping power in suppressing quantum noise and controlling the width of quantum interference channels are analyzed carefully.Furthermore,quantum noise suppression at quadrature amplitude is obtained with phase-sensitive modulation.It shows that the entanglement strength of the output field and the quantum noise suppression effect can be enhanced significantly by a strong pumping filed due to interaction of pumping light with the nonlinear crystal.The full width at half maxima(FWHM)of the noise curve at the resonant peak(△=0 MHz)is broadened up to 2.17 times compared to the single cavity.In the strong coupling resonant system,the FWHM at △=0 MHz(△=±3.1 MHz)is also broadened up to 1.27(3.53)times compared to the weak coupling resonant system case.The multi-channel quantum interference creates an electromagnetically induced transparent-like line shape,which can be used to improve the transmission efficiency and stability of wave packets in quantum information processing and quantum memory.
文摘提出基于布里渊光时域反射(Brillouin optic time domain reflectometer,BOTDR)分布式检测技术与解调信号的光缆隐蔽性缺陷识别方法,识别检测光缆隐蔽性缺陷。在生产阶段将光纤植入多股碳纤维导线复合芯内部作为传感器,依据BOTDR技术与光时域反射(optic time domain reflectometer,OTDR)技术原理,构建关于碳纤维导线光缆隐蔽性检测的分布式传感系统,利用光纤对温度、应力、传播损耗的高精度感知,多维度地分析碳纤维导线光缆的隐蔽性缺陷及位置分布,实现光缆的隐蔽性缺陷识别。利用morlet小波解调布里渊散射信号,提取包络信息,去除信号噪声,采用列文伯格-马夸尔特算法,拟合布里渊散射谱数据,精确估计最优Brillouin频移量参数,提升整体缺陷识别精度。实验证明:该方法可以准确地对光缆的隐蔽性缺陷进行表征,实现多股碳纤维导线光缆隐蔽性缺陷的快速、有效识别,促进碳纤维导线光缆更好地应用于增容、大跨越等工程中。
基金Project partially supported by the National Natural Science Foundation of China (Grant Nos 10527003 and 60672104)the State Key Development Program for Basic Research of China (Grant No 2006CB705700-05)+1 种基金Joint Research Foundation of Beijing Education Committee (Grant No SYS100010401)Beijing Natural Science Foundation (Grant No 3073019)
文摘Robust and fast fat suppression is a challenge in balanced steady-state free precession （SSFP） magnetic resonance imaging. Although single-acquisition phase-sensitive SSFP can provide fat-suppressed images in short scan time, phase errors, especially spatially-dependent phase shift, caused by a variety of factors may result in misplacement of fat and water voxels. In this paper, a novel phase correction algorithm was used to calibrate those phase errors during image reconstruction. This algorithm corrects phase by region growing, employing both the magnitude and the phase information of image pixels. Phantom and in vivo imagings were performed to validate the technique. As a result, excellent fat-suppressed images were acquired by using single-acquisition phase-sensitive SSFP with phase correction.
基金Supported by Haikou Key Science and Technology Project (2012-075)Haikou Science and Technology Planning Project(2009-049-1)Science and Technology Fund of Haikou Health Bureau(2010-SWY-13-058)
文摘Objective:Late gadolinium enhancement(LGE) patterns of cardiovascular magnetic resonance (CMR) relying on PSIR(phase-sensitive inversion recovery sequence) techniques had been used to determine the characteristics of LGE in apical hypertrophic cardiomyopathy(ApHCM). Methods:Forty patients pure ApHCM[age,(60.2±10.4) years,31 men]were enrolled.LGE images were acquired using PSIR,and analyzed using a 17-segment model.Summing the LGE areas in all short axis slices yielded the total volume of late enhancement,which was subsequently presented as a proportion of total LV myocardium(%LGE).Results:Mean maximal apical wall thickness was(17.9±2.3) mm,and mean left ventricular(LV) ejection fraction was(67.7±8.0)%.LGE was detected in 130 segments of 30 patients(75.0%),occupying(4.9±5.5)% of LV myocardium.LGE was mainly detected at the junction between left and right ventricles in 12(30%) and at the apex in 28(70%),although LGE-positive areas were widely distributed,and not limited to the apex.Focal LGE at the non-hypertrophic LV segments was found in some ApHCM patients,even without LGE of hypertrophied apical segments.Conclusions:LGE was frequently observed not only in the thickened apex of the heart but also in other LV segments,irrespective of the presence or absence of hypertrophy.The simple presence of LGE on CMR was not representative of adverse prognosis in this population.
基金Supported by the National Natural Science Foundation of China under Grant Nos U0934001 and 11076028the Science and Technology Commission of Shanghai Municipality under Grant Nos 11DZ1140202 and 13XD1425400the Pudong New Area Science and Technology Development Fund of China under Grant No PKJ2012-D04
文摘A phase-sensitive optical time domain reflectometer （φ-OTDR） based on a 120°-phase-difference Michelson in- terferometer is proposed. The Michelson interferometer with arm difference of 4m is used to test the phase difference between the Rayleigh scattering from two sections of the fiber. A new demodulation method called the inverse transmission matrix demodulation scheme is utilized to demodulate the distributed phase from the backward scattering along the long fiber, The experimental results show that the 120°-phase-difference inter- ferometer φ-OTDR can detect the phase along the 3km fiber, and the acoustic signal within the whole human hearing range of 20 Hz-20 kHz is reproduced accurately and quickly.
基金supported by Haikou Key Science and Technology Project (2012-075)Haikou Science and Technology Planning Project(2009-049-1)Science and Technology Fund of Haikou Health Bureau(2010-SWY-13-058)
文摘Objective:To determine the deference between phase sensitive magnetic resonance(MR) imaging and magnitude reconstruction to detect infracted myocardium.Methods:Twenty patients(16 men;4 women;mean age,56 years),experienced Q-wave myocardial infarction 2 weeks earlier were examined with a 3.0-T MR system 10 minutes after administration of 0.1 mmol/kg body weight gadobenate dimeglumine.To determine the optimal TI,a TI scout sequence was used.A segmented 2D IR true fast imaging with steady-state precession(trueFISP) sequence that produces both phase-sensitive and magnitude-reconstructed images were used at TI values of 200-600 msec(TI values were varied in 100-msec steps) and at optimal TI(mean value,330 msec).Contrast- noise ratios(CNRs) of normal and infarcted myocardium and the area of infarcted myocardium were determined.Two-tailed unpaired sample Student t test was used to compare CNRs,and area of infarction.Results:MMean CNR phase-sensitive and magnitude-reconstructed images at optimal TI(mean value,330 msec) were 6.2,and 6.1,respectively.For a TI of 200 msec,CNR values were 5.5,and 4.2,respectively;for TI of 600 msec,CNR values were 5.8 and 4.3,respectively.Area of infarcted myocardium was underestimated on magnitude-reconstruction images(P = 0.002-0.03) for short TI values(ie.,200 msec) but not on phase sensitive reconstructed when compared with IR tureFISP images obtained at optimal TI.Conclusions: LPhase-sensitive image reconstruction results in reduced need for precise choice of TI and more consistent image quality.
基金Project supported by the National Natural Science Foundation of China(Grant Nos60308002and60678005)the Foundation for the Author of National Excellent Doctoral Dissertation of China(Grant No200339)+2 种基金the Foundation for Key Program of Ministry of Education,China(Grant No105156)the Fok Ying-Tong Education Foundation for Young Teachers in the Higher Education Institutions of China(Grant No101061)the Specialized Research Fund for the Doctoral Program of Higher Education of China(Grant No20050698017)
文摘We study the colour-locked twin-noisy-field correlation effects in the fifth-order nonlinear susceptibility of ultrafast polarization beats in a cascade four-level system. More importantly, the fifth-order phase-sensitive heterodyne detection of ultrafast polarization beats has been exploited. The fifth-order nonlinear optical response can be controlled and modified through the colour-locked correlation of twin noisy fields. Thus, this method with the phase dispersion information is a good way to measure the real and imaginary parts of the fifth-order nonlinear susceptibility.
