The aberration in the received acoustic field and the Doppler shift in the forward scattered field are simultaneously induced when a submerged target crosses the source–receiver line.Formulations for the two variatio...The aberration in the received acoustic field and the Doppler shift in the forward scattered field are simultaneously induced when a submerged target crosses the source–receiver line.Formulations for the two variations are developed upon an ideal forward scattering configuration.Both the field aberration and the Doppler shift are expressed as functions of the same argument—the target motion time.An experimental validation was carried out in a tank,in which the continuous wave was transmitted.The field aberration and the Doppler shift were extracted from the collected data by the simple Hilbert transform and a hybrid technique,respectively.The measured aberration and Doppler shift agree with the theoretical results.Simultaneous detection outputs are beneficial to enhance the reliability on target detection by providing both the aberrations in the received acoustic field and the Doppler shift in the forward scattered field.展开更多
Maximum likelihood(ML) noncoherent block detection techniques are investigated for block-coded MPSK modulation in cooperative decode-and-forward relay systems over slow fading channels.A decision-directed iterative Vi...Maximum likelihood(ML) noncoherent block detection techniques are investigated for block-coded MPSK modulation in cooperative decode-and-forward relay systems over slow fading channels.A decision-directed iterative Viterbi algorithm(IVA) is derived for a suboptimal ML noncoherent detection.Simulation results show that the IVA can approach the error performances of the exhaustive detection method but at a lower complexity.展开更多
This study aims to examine the explicit solution for calculating the Average Run Length(ARL)on the triple exponentially weighted moving average(TEWMA)control chart applied to autoregressive model(AR(p)),where AR(p)is ...This study aims to examine the explicit solution for calculating the Average Run Length(ARL)on the triple exponentially weighted moving average(TEWMA)control chart applied to autoregressive model(AR(p)),where AR(p)is an autoregressive model of order p,representing a time series with dependencies on its p previous values.Additionally,the study evaluates the accuracy of both explicit and numerical integral equation(NIE)solutions for AR(p)using the TEWMA control chart,focusing on the absolute percentage relative error.The results indicate that the explicit and approximate solutions are in close agreement.Furthermore,the study investigates the performance of exponentially weighted moving average(EWMA)and TEWMA control charts in detecting changes in the process,using the relative mean index(RMI)as a measure.The findings demonstrate that the TEWMA control chart outperforms the EWMA control chart in detecting process changes,especially when the value ofλis sufficiently large.In addition,an analysis using historical data from the SET index between January 2024 and May 2024 and historical data of global annual plastic production,the results of both data sets also emphasize the superior performance of the TEWMA control chart.展开更多
This paper introduces a new modulation and direct detection scheme of optical phase shift keying (PSK) which is simple and practical in fiber optical communication. A phase modulator is used to modulate a continuous w...This paper introduces a new modulation and direct detection scheme of optical phase shift keying (PSK) which is simple and practical in fiber optical communication. A phase modulator is used to modulate a continuous wave (CW) laser source and return-to-zero (RZ) signal that is changed from the initial transmitting information is used to control a phase modulator to form a optical PSK signal. In the receiver terminal, just add a signal delayed a half of one bit to itself so that the initial information can be restored.展开更多
A phase shift demodulation technique based on subtraction capable of measuring 0.03 phase degree limit between sinusoidal signals is presented in this paper. A self-gain module and a practical subtracter act the kerne...A phase shift demodulation technique based on subtraction capable of measuring 0.03 phase degree limit between sinusoidal signals is presented in this paper. A self-gain module and a practical subtracter act the kernel parts of the phase shift demodulation system. Electric signals in different phases are used to verify the performance of the system. In addition, a new designed optical source, laser fiber differential source （LFDS）, capable of generating mini phase is used to further verify the system reliability. R-square of 0.99997 in electric signals and R-square of 0.99877 in LFDS are achieved, and 0.03 degree measurement limit is realized in experiments. Furthermore, the phase shift demodulation system is applied to the fluorescence phase based oxygen sensors to realize the fundamental function. The experimental results reveal that a good repetition and better than 0.02% oxygen concentration measurement accuracy are realized. In addition, the phase shift demodulation system can be easily integrated to other applications.展开更多
Despite advances in the multicolor luminescence of Ce-activated materials,achieving efficient and stable near-ultraviolet(n-UV)emission remains a critical challenge.On the basis of structural rigidity engineering,a sm...Despite advances in the multicolor luminescence of Ce-activated materials,achieving efficient and stable near-ultraviolet(n-UV)emission remains a critical challenge.On the basis of structural rigidity engineering,a small Stokes shift(△S=0.53 eV)of Ce in microwave-hydrothermally synthesized NaSrY(PO_(4))_(2)(NSYP)nanophosphors is achieved,addressing this shortage.The internal quantum efficiency reaches as high as 98.5%(λ_(ex)=325 nm)along with superior thermostability(78%intensity retention at 423 K)andexceptional solvent resistance(82%after 10 days of immersion).The optimal nanomaterial is used as a scintillation screen for X-ray imaging,achieving a high spatial resolution of 11.0 Ip/mm and clear imaging of measured objects,rivaling a commercial scintillator(Cst:TI).A high relative sensitivity(S_(R-max)=0.94(%)-K^(-1))is achieved for excitation intensity ratio(EIR)technology-based opticall thermometry.This work presents fascinating applications in X-ray imaging and optical thermometry for n-UV-emittingl nanophosphors.These findings also highlight the critical role of host structure in designing high-quality Ce-activated optical materials.展开更多
The investigation of a novel thermal neutron detector is developed to fulfill the requirements of the high intensity power diffractometer （HIPD） at the Chinese Spallation Neutron Source （CSNS）. It consists of two ...The investigation of a novel thermal neutron detector is developed to fulfill the requirements of the high intensity power diffractometer （HIPD） at the Chinese Spallation Neutron Source （CSNS）. It consists of two layers of 6LiF/ZnS（Ag） scintillators, two layers of crossed WLSF arrays, several multi-anode photo multiplier tubes （MA-PMT）, and the matching readout electronics. The neutron detection efficiency of the scintilltors, the light transportation ability of the WLSF, and the spatial linearity of the readout electronics are measured and discussed in this paper. It shows that the sandwich structure and the compact readout electronics could fulfill the needs of the HIPD. A prototype with a 10 cm×10 cm sensitive area has been constructed to further study the characteristics of the neutron scintillator detector.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.11174235 and 61571366)
文摘The aberration in the received acoustic field and the Doppler shift in the forward scattered field are simultaneously induced when a submerged target crosses the source–receiver line.Formulations for the two variations are developed upon an ideal forward scattering configuration.Both the field aberration and the Doppler shift are expressed as functions of the same argument—the target motion time.An experimental validation was carried out in a tank,in which the continuous wave was transmitted.The field aberration and the Doppler shift were extracted from the collected data by the simple Hilbert transform and a hybrid technique,respectively.The measured aberration and Doppler shift agree with the theoretical results.Simultaneous detection outputs are beneficial to enhance the reliability on target detection by providing both the aberrations in the received acoustic field and the Doppler shift in the forward scattered field.
基金supported by the National Natural Science Foundation of China(61302095,61401165)the Natural Science Foundation of Fujian Province of China(2014J01243,2014J05076,2015J01262)the Huaqiao University Science Foundation(13Y0384)
文摘Maximum likelihood(ML) noncoherent block detection techniques are investigated for block-coded MPSK modulation in cooperative decode-and-forward relay systems over slow fading channels.A decision-directed iterative Viterbi algorithm(IVA) is derived for a suboptimal ML noncoherent detection.Simulation results show that the IVA can approach the error performances of the exhaustive detection method but at a lower complexity.
基金the National Science,Research and Innovation Fund(NSRF)King Mongkuts University of Technology North Bangkok under contract no.KMUTNB-FF-68-B-08.
文摘This study aims to examine the explicit solution for calculating the Average Run Length(ARL)on the triple exponentially weighted moving average(TEWMA)control chart applied to autoregressive model(AR(p)),where AR(p)is an autoregressive model of order p,representing a time series with dependencies on its p previous values.Additionally,the study evaluates the accuracy of both explicit and numerical integral equation(NIE)solutions for AR(p)using the TEWMA control chart,focusing on the absolute percentage relative error.The results indicate that the explicit and approximate solutions are in close agreement.Furthermore,the study investigates the performance of exponentially weighted moving average(EWMA)and TEWMA control charts in detecting changes in the process,using the relative mean index(RMI)as a measure.The findings demonstrate that the TEWMA control chart outperforms the EWMA control chart in detecting process changes,especially when the value ofλis sufficiently large.In addition,an analysis using historical data from the SET index between January 2024 and May 2024 and historical data of global annual plastic production,the results of both data sets also emphasize the superior performance of the TEWMA control chart.
文摘This paper introduces a new modulation and direct detection scheme of optical phase shift keying (PSK) which is simple and practical in fiber optical communication. A phase modulator is used to modulate a continuous wave (CW) laser source and return-to-zero (RZ) signal that is changed from the initial transmitting information is used to control a phase modulator to form a optical PSK signal. In the receiver terminal, just add a signal delayed a half of one bit to itself so that the initial information can be restored.
基金This work was supported by the National Natural Science Foundation of China （61475085）, Science and Technology Development Project of Shandong Province （2014GGX101007）, and the Fundamental Research Funds of Shandong University （2014YQ011）.
文摘A phase shift demodulation technique based on subtraction capable of measuring 0.03 phase degree limit between sinusoidal signals is presented in this paper. A self-gain module and a practical subtracter act the kernel parts of the phase shift demodulation system. Electric signals in different phases are used to verify the performance of the system. In addition, a new designed optical source, laser fiber differential source （LFDS）, capable of generating mini phase is used to further verify the system reliability. R-square of 0.99997 in electric signals and R-square of 0.99877 in LFDS are achieved, and 0.03 degree measurement limit is realized in experiments. Furthermore, the phase shift demodulation system is applied to the fluorescence phase based oxygen sensors to realize the fundamental function. The experimental results reveal that a good repetition and better than 0.02% oxygen concentration measurement accuracy are realized. In addition, the phase shift demodulation system can be easily integrated to other applications.
基金supported by the Yunnan Fundamental Research Project(No.202401AS070128)the Yunnan Doctoral Student Service Industry Scientific Research and Innovation Cultivation Project(Nos.FWCY-BSPY2024028 and FWCYBSPY2024027)the National Natural Science Foundation of China(Nos.22165031 and 62475248).
文摘Despite advances in the multicolor luminescence of Ce-activated materials,achieving efficient and stable near-ultraviolet(n-UV)emission remains a critical challenge.On the basis of structural rigidity engineering,a small Stokes shift(△S=0.53 eV)of Ce in microwave-hydrothermally synthesized NaSrY(PO_(4))_(2)(NSYP)nanophosphors is achieved,addressing this shortage.The internal quantum efficiency reaches as high as 98.5%(λ_(ex)=325 nm)along with superior thermostability(78%intensity retention at 423 K)andexceptional solvent resistance(82%after 10 days of immersion).The optimal nanomaterial is used as a scintillation screen for X-ray imaging,achieving a high spatial resolution of 11.0 Ip/mm and clear imaging of measured objects,rivaling a commercial scintillator(Cst:TI).A high relative sensitivity(S_(R-max)=0.94(%)-K^(-1))is achieved for excitation intensity ratio(EIR)technology-based opticall thermometry.This work presents fascinating applications in X-ray imaging and optical thermometry for n-UV-emittingl nanophosphors.These findings also highlight the critical role of host structure in designing high-quality Ce-activated optical materials.
基金Supported by National Natural Science Foundation of China(11175257)Key Laboratory of Neutron Detection and Electronics of Dongguan Municipality
文摘The investigation of a novel thermal neutron detector is developed to fulfill the requirements of the high intensity power diffractometer （HIPD） at the Chinese Spallation Neutron Source （CSNS）. It consists of two layers of 6LiF/ZnS（Ag） scintillators, two layers of crossed WLSF arrays, several multi-anode photo multiplier tubes （MA-PMT）, and the matching readout electronics. The neutron detection efficiency of the scintilltors, the light transportation ability of the WLSF, and the spatial linearity of the readout electronics are measured and discussed in this paper. It shows that the sandwich structure and the compact readout electronics could fulfill the needs of the HIPD. A prototype with a 10 cm×10 cm sensitive area has been constructed to further study the characteristics of the neutron scintillator detector.
