We propose and experimentally demonstrate a novel Raman-based distributed fiber-optics temperature sensor(RDTS) for improving the temperature measurement accuracy and engineering applicability. The proposed method is ...We propose and experimentally demonstrate a novel Raman-based distributed fiber-optics temperature sensor(RDTS) for improving the temperature measurement accuracy and engineering applicability. The proposed method is based on double-ended demodulation with a reference temperature and dynamic dispersion difference compensation method, which can suppress the effect of local external physics perturbation and intermodal dispersion on temperature demodulation results. Moreover, the system can omit the pre-calibration process by using the reference temperature before the temperature measurement. The experimental results of dispersion compensation indicate that the temperature accuracy optimizes from 5.6°C to 1.2°C, and the temperature uncertainty decreases from 16.8°C to 2.4°C. Moreover, the double-ended configuration can automatically compensate the local external physics perturbation of the sensing fiber, which exhibits a distinctive improvement.展开更多
Lead sulfide(PbS)colloidal quantum dot(CQD)photodiodes integrated with silicon-based readout integrated circuits(ROICs)offer a promising solution for the next-generation short-wave infrared(SWIR)imaging technology.Des...Lead sulfide(PbS)colloidal quantum dot(CQD)photodiodes integrated with silicon-based readout integrated circuits(ROICs)offer a promising solution for the next-generation short-wave infrared(SWIR)imaging technology.Despite their potential,large-size CQD photodiodes pose a challenge due to high dark currents resulting from surface states on nonpassivated(100)facets and trap states generated by CQD fusion.In this work,we present a novel approach to address this issue by introducing double-ended ligands that supplementally passivate(100)facets of halidecapped large-size CQDs,leading to suppressed bandtail states and reduced defect concentration.Our results demonstrate that the dark current density is highly suppressed by about an order of magnitude to 9.6 nA cm^(2) at -10 mV,which is among the lowest reported for PbS CQD photodiodes.Furthermore,the performance of the photodiodes is exemplary,yielding an external quantum efficiency of 50.8%(which corresponds to a responsivity of 0.532 A W^(-1))and a specific detectivity of 2.5×10^(12) Jones at 1300 nm.By integrating CQD photodiodes with CMOS ROICs,the CQD imager provides high-resolution(640×512)SWIR imaging for infrared penetration and material discrimination.展开更多
The distribution network exhibits complex structural characteristics,which makes fault localization a challenging task.Especially when a branch of the multi-branch distribution network fails,the traditional multi-bran...The distribution network exhibits complex structural characteristics,which makes fault localization a challenging task.Especially when a branch of the multi-branch distribution network fails,the traditional multi-branch fault location algorithm makes it difficult to meet the demands of high-precision fault localization in the multi-branch distribution network system.In this paper,the multi-branch mainline is decomposed into single branch lines,transforming the complex multi-branch fault location problem into a double-ended fault location problem.Based on the different transmission characteristics of the fault-traveling wave in fault lines and non-fault lines,the endpoint reference time difference matrix S and the fault time difference matrix G were established.The time variation rule of the fault-traveling wave arriving at each endpoint before and after a fault was comprehensively utilized.To realize the fault segment location,the least square method was introduced.It was used to find the first-order fitting relation that satisfies the matching relationship between the corresponding row vector and the first-order function in the two matrices,to realize the fault segment location.Then,the time difference matrix is used to determine the traveling wave velocity,which,combined with the double-ended traveling wave location,enables accurate fault location.展开更多
For uniform tube inner coating of non-conductive thin films, the double-ended coaxial magnetron pulsed plasma (DCMPP) method was investigated. In this study, coating of TiN and TiO2 was performed. It was clearly shown...For uniform tube inner coating of non-conductive thin films, the double-ended coaxial magnetron pulsed plasma (DCMPP) method was investigated. In this study, coating of TiN and TiO2 was performed. It was clearly shown that the extended anode effect was strongly influenced by the electric resistance of the coated thin films on the inner surface of an insulator tube. Additionally, high frequency (100 kHz) was better for relatively high plasma density. On the other hand, in the case of titanium oxide deposition, negative ion productions drastically decrease the deposition rate and the shifting velocity of plasma main position for coated TiO2 films.展开更多
The DC grid technology of multi-power supply and multi-drop-point power reception is an effective solution for large-scale renewable energy integration into the power grid.Line-commutated converter-Voltage source conv...The DC grid technology of multi-power supply and multi-drop-point power reception is an effective solution for large-scale renewable energy integration into the power grid.Line-commutated converter-Voltage source converter(LCC-VSC)power grids are one of the more important developmental directions of the future power grid that have occured in recent years.But the multi-terminal high voltage direct current system has the problems of inconsistent boundary characteristics,inconsistent control,and fault response characteristics,which puts higher requirements on the protection scheme.Thus,a completely new protection principle is proposed in this paper.Firstly,the fault characteristics of distributed capacitance current are analyzed.The reactive power calculated by the distribution parameters of different frequencies is different.Subsequently,the fault characteristics of DC reactive power are analyzed,and a DC reactive power extraction algorithm is proposed.The polarity of the multi-band DC reactive power is used to construct the protection scheme.Finally,the LCC-VSC power grid model verifies the correctness and superiority of the proposed protection scheme.The proposed scheme uses DC reactive power instead of fault current to solve the long delay problem caused by distributed capacitance.Compared with the prior art,the proposed solution is not affected by distributed capacitance and has a stronger anti-interference ability(600Ω+10 dB+1 ms).展开更多
The micro-electromechanical system(MEMS)infrared thermopile is the core working device of modern information detection systems such as spectrometers,gas sensors,and remote temperature sensors.We presented two differen...The micro-electromechanical system(MEMS)infrared thermopile is the core working device of modern information detection systems such as spectrometers,gas sensors,and remote temperature sensors.We presented two different structures of MEMS infrared thermopiles based on suspended film structures.They both deposited silicon nitride over the entire surface as a passivated absorber layer in place of a separate absorber zone,and the thermocouple strip was oriented in the same direction as the temperature gradient.The same MEMS preparation process was used and finally two different structures of the thermopile were characterized separately for testing to verify the impact of our design on the detector.The test results show that the circular and double-ended symmetrical thermopile detectors have responsivities of 27.932 V/W and 23.205 V/W,specific detectivities of 12.1×10^(7) cm·Hz^(1/2)·W^(-1) and 10.1×10^(7) cm·Hz^(1/2)·W^(-1),and response time of 26.2 ms and 27.06 ms,respectively.In addition,rectangular double-ended symmetric thermopile has a larger field of view than a circular thermopile detector,but is not as mechanically stable as a circular thermopile.展开更多
基金supported by the National Natural Science Foundation of China (NSFC) (Nos. 61527819 and 61875146)the Research Project by Shanxi Scholarship Council of China (Nos. 2016-036 and 2017-052)+2 种基金the Key Science and Technology Research Project Based on Coal of Shanxi Province (No. MQ2014-09)the Program for the Outstanding Innovative Teams of Higher Learning Institutions of Shanxithe Program for Sanjin Scholar
文摘We propose and experimentally demonstrate a novel Raman-based distributed fiber-optics temperature sensor(RDTS) for improving the temperature measurement accuracy and engineering applicability. The proposed method is based on double-ended demodulation with a reference temperature and dynamic dispersion difference compensation method, which can suppress the effect of local external physics perturbation and intermodal dispersion on temperature demodulation results. Moreover, the system can omit the pre-calibration process by using the reference temperature before the temperature measurement. The experimental results of dispersion compensation indicate that the temperature accuracy optimizes from 5.6°C to 1.2°C, and the temperature uncertainty decreases from 16.8°C to 2.4°C. Moreover, the double-ended configuration can automatically compensate the local external physics perturbation of the sensing fiber, which exhibits a distinctive improvement.
基金National Natural Science Foundation of China,Grant/Award Numbers:U22A2083,62204091,62374068National Key Research and Development Program of China,Grant/Award Number:2021YFA0715502+5 种基金Key R&D program of Hubei Province,Grant/Award Number:2021BAA014Innovation Project of Optics Valley Laboratory,Grant/Award Numbers:OVL2021BG009,OVL2023ZD002Exploration Project of Natural Science Foundation of Zhejiang Province,Grant/Award Number:LY23F040005Fund for Innovative Research Groups of the Natural Science Foundation of Hubei Province,Grant/Award Number:2020CFA034Fund from Science,Technology and Innovation Commission of Shenzhen Municipality,Grant/Award Numbers:GJHZ20210705142540010,GJHZ20220913143403007China Postdoctoral Science Foundation,Grant/Award Numbers:2021M691118,2022M711237,2022M721243,2023T160244。
文摘Lead sulfide(PbS)colloidal quantum dot(CQD)photodiodes integrated with silicon-based readout integrated circuits(ROICs)offer a promising solution for the next-generation short-wave infrared(SWIR)imaging technology.Despite their potential,large-size CQD photodiodes pose a challenge due to high dark currents resulting from surface states on nonpassivated(100)facets and trap states generated by CQD fusion.In this work,we present a novel approach to address this issue by introducing double-ended ligands that supplementally passivate(100)facets of halidecapped large-size CQDs,leading to suppressed bandtail states and reduced defect concentration.Our results demonstrate that the dark current density is highly suppressed by about an order of magnitude to 9.6 nA cm^(2) at -10 mV,which is among the lowest reported for PbS CQD photodiodes.Furthermore,the performance of the photodiodes is exemplary,yielding an external quantum efficiency of 50.8%(which corresponds to a responsivity of 0.532 A W^(-1))and a specific detectivity of 2.5×10^(12) Jones at 1300 nm.By integrating CQD photodiodes with CMOS ROICs,the CQD imager provides high-resolution(640×512)SWIR imaging for infrared penetration and material discrimination.
基金This work was funded by the project of State Grid Hunan Electric Power Research Institute(No.SGHNDK00PWJS2210033).
文摘The distribution network exhibits complex structural characteristics,which makes fault localization a challenging task.Especially when a branch of the multi-branch distribution network fails,the traditional multi-branch fault location algorithm makes it difficult to meet the demands of high-precision fault localization in the multi-branch distribution network system.In this paper,the multi-branch mainline is decomposed into single branch lines,transforming the complex multi-branch fault location problem into a double-ended fault location problem.Based on the different transmission characteristics of the fault-traveling wave in fault lines and non-fault lines,the endpoint reference time difference matrix S and the fault time difference matrix G were established.The time variation rule of the fault-traveling wave arriving at each endpoint before and after a fault was comprehensively utilized.To realize the fault segment location,the least square method was introduced.It was used to find the first-order fitting relation that satisfies the matching relationship between the corresponding row vector and the first-order function in the two matrices,to realize the fault segment location.Then,the time difference matrix is used to determine the traveling wave velocity,which,combined with the double-ended traveling wave location,enables accurate fault location.
文摘For uniform tube inner coating of non-conductive thin films, the double-ended coaxial magnetron pulsed plasma (DCMPP) method was investigated. In this study, coating of TiN and TiO2 was performed. It was clearly shown that the extended anode effect was strongly influenced by the electric resistance of the coated thin films on the inner surface of an insulator tube. Additionally, high frequency (100 kHz) was better for relatively high plasma density. On the other hand, in the case of titanium oxide deposition, negative ion productions drastically decrease the deposition rate and the shifting velocity of plasma main position for coated TiO2 films.
基金supported by the National Natural Science Foundation of China-State Grid Joint Fund for Smart Grid(No.U2066210).
文摘The DC grid technology of multi-power supply and multi-drop-point power reception is an effective solution for large-scale renewable energy integration into the power grid.Line-commutated converter-Voltage source converter(LCC-VSC)power grids are one of the more important developmental directions of the future power grid that have occured in recent years.But the multi-terminal high voltage direct current system has the problems of inconsistent boundary characteristics,inconsistent control,and fault response characteristics,which puts higher requirements on the protection scheme.Thus,a completely new protection principle is proposed in this paper.Firstly,the fault characteristics of distributed capacitance current are analyzed.The reactive power calculated by the distribution parameters of different frequencies is different.Subsequently,the fault characteristics of DC reactive power are analyzed,and a DC reactive power extraction algorithm is proposed.The polarity of the multi-band DC reactive power is used to construct the protection scheme.Finally,the LCC-VSC power grid model verifies the correctness and superiority of the proposed protection scheme.The proposed scheme uses DC reactive power instead of fault current to solve the long delay problem caused by distributed capacitance.Compared with the prior art,the proposed solution is not affected by distributed capacitance and has a stronger anti-interference ability(600Ω+10 dB+1 ms).
基金This work was supported in part by the National Natural Science Foundation of China(Grant No.51935011)Innovative Research Group Project of National Science Foundation of China(Grant No.51821003)+1 种基金Fund for Shanxi“1331 Project”Key Subject Construction,Key Research and Development Project of Shanxi Province(Grant Nos.202102030201001 and 202102030201009)Key Special Project of Science and Technology of Shanxi Province(Grant No.202201030201004).
文摘The micro-electromechanical system(MEMS)infrared thermopile is the core working device of modern information detection systems such as spectrometers,gas sensors,and remote temperature sensors.We presented two different structures of MEMS infrared thermopiles based on suspended film structures.They both deposited silicon nitride over the entire surface as a passivated absorber layer in place of a separate absorber zone,and the thermocouple strip was oriented in the same direction as the temperature gradient.The same MEMS preparation process was used and finally two different structures of the thermopile were characterized separately for testing to verify the impact of our design on the detector.The test results show that the circular and double-ended symmetrical thermopile detectors have responsivities of 27.932 V/W and 23.205 V/W,specific detectivities of 12.1×10^(7) cm·Hz^(1/2)·W^(-1) and 10.1×10^(7) cm·Hz^(1/2)·W^(-1),and response time of 26.2 ms and 27.06 ms,respectively.In addition,rectangular double-ended symmetric thermopile has a larger field of view than a circular thermopile detector,but is not as mechanically stable as a circular thermopile.
