流化床反应器(Fluidized bed reactor,FBR)是以液相和固相的两相混合为特征,固相颗粒通过向下或向上的循环流实现流态化的一类生物反应器,在废水处理领域有较好的发展前景.本文主要介绍了FBR的研究现状,重点综述了FBR的新发展,包括分离...流化床反应器(Fluidized bed reactor,FBR)是以液相和固相的两相混合为特征,固相颗粒通过向下或向上的循环流实现流态化的一类生物反应器,在废水处理领域有较好的发展前景.本文主要介绍了FBR的研究现状,重点综述了FBR的新发展,包括分离固体产物、逆流流化床、与生物膜结合、与各种生物电化学系统结合以及厌氧-好氧工艺组合等新方向.展开更多
We report a high-stability ultrafast ultraviolet(UV)laser source at 352 nm by exploring an all-fiber,all-polarizationmaintaining(all-PM),Yb-doped femtosecond fiber laser at 1060 nm.The output power,pulse width,and opt...We report a high-stability ultrafast ultraviolet(UV)laser source at 352 nm by exploring an all-fiber,all-polarizationmaintaining(all-PM),Yb-doped femtosecond fiber laser at 1060 nm.The output power,pulse width,and optical spectrum width of the fiber laser are 6 W,244 fs,and 17.5 nm,respectively.The UV ultrashort pulses at a repetition rate of 28.9 MHz are generated by leveraging single-pass second-harmonic generation in a 1.3-mm-long BiB_(3)O_(6)(BIBO)and sum frequency generation in a 5.1-mm-long BIBO.The maximum UV output power is 596 mW.The root mean square error of the output power of UV pulses is 0.54%.This laser,with promising stability,is expected to be a nice source for frontier applications in the UV wavelength window.展开更多
This research interprets the background of Jinzhou section of the Peking-Mukden Railway,and puts forward 65 heritages as cases based on the scope definition and investigation.After the data collection,processing,and v...This research interprets the background of Jinzhou section of the Peking-Mukden Railway,and puts forward 65 heritages as cases based on the scope definition and investigation.After the data collection,processing,and visualization,the database composed of 9 sub-databases,with B/S architecture mode,is constructed based on SQL server platform.The ArcGIS tool is used to analyze the distribution of the heritages,including spatial distribution characteristics,spatial agglomeration,and spatial equilibrium.“Image and model information database”and“text attribute information database”is used to analyze the architectural ontology features.The conclusions are drawn as follows:1)The integral distribution has the characteristics of“cohesion”,while the 5 medium types of heritages show obvious and different directions.2)The overall pattern of spatial agglomeration is characterized by high cohesion with a single high agglomeration point as the core.The low agglomeration area shows a point-line-point pattern.3)The integral heritages and three main types of buildings differ in distribution,and the equilibrium is low.The architectural ontology analysis shows that the image information can be used as the basis for ontology characteristics analysis,architectural form and style judgment,and architectural functional space analysis.展开更多
In this work,we present a high-power,high-repetition-rate,all-fiber femtosecond laser system operating at 1.5μm.This all-fiber laser system can deliver femtosecond pulses at a fundamental repetition rate of 10.6 GHz ...In this work,we present a high-power,high-repetition-rate,all-fiber femtosecond laser system operating at 1.5μm.This all-fiber laser system can deliver femtosecond pulses at a fundamental repetition rate of 10.6 GHz with an average output power of 106.4 W–the highest average power reported so far from an all-fiber femtosecond laser at 1.5μm,to the best of our knowledge.By utilizing the soliton-effect-based pulse compression effect with optimized pre-chirping dispersion,the amplified pulses are compressed to 239 fs in an all-fiber configuration.Empowered by such a high-power ultrafast fiber laser system,we further explore the nonlinear interaction among transverse modes LP01,LP11 and LP21 that are expected to potentially exist in fiber laser systems using large-mode-area fibers.The intermodal modulational instability is theoretically investigated and subsequently identified in our experiments.Such a high-power all-fiber ultrafast laser without bulky free-space optics is anticipated to be a promising laser source for applications that specifically require compact and robust operation.展开更多
Objective:To investigate the efficacy of in-phase and quadrature(IQ)demodulation in electronic fetal heart rate monitoring(EFM)to reduce false reports of fetal heart rate(FHR)doubling or halving.Methods:This is a pros...Objective:To investigate the efficacy of in-phase and quadrature(IQ)demodulation in electronic fetal heart rate monitoring(EFM)to reduce false reports of fetal heart rate(FHR)doubling or halving.Methods:This is a prospective cohort study.A total of 263 full-term pregnant women who delivered at Peking University Shenzhen Hospital between August 2019 and July 2020 were prospectively enrolled in the study.FHR monitoring began when the cervix was dilated to 2-3 cm and continued until delivery.Raw fetal Doppler audio signals and internal and external cardiotocography curves from internal electrode monitoring,EFM with conventional demodulation(external),and EFM with IQ demodulation(external)were acquired to compare FHR doubling and halving time.In cohort 1,FHR was compared between IQ demodulation and conventional demodulation.In cohort 2,FHR was compared between IQ demodulation,conventional demodulation,and internal FHR monitoring.Count data were statistically analyzed using the Chi-squared test,and measurement data were statistically analyzed usingt-test for correlation coefficients,and Bland-Altman analysis for concordance ranges.Results:To compare IQ demodulation and conventional demodulation,225 pregnant women were monitored for a total of 835,870 seconds.The beat-to-beat interval of FHRs in raw fetal Doppler audio signals was used as the reference.The results showed a doubling time of 3401 seconds(0.407%,3401/835,870)and a halving time of 2918 seconds(0.349%,2918/835,870)with conventional demodulation,compared to 241 seconds(0.029%,241/835,870)and 589 seconds(0.070%,589/835,870),respectively,with IQ demodulation.IQ demodulation reduced FHR doubling by approximately 93%(3160/3401)and FHR halving by approximately 80%(2329/2918)compared to conventional demodulation(P<0.01).Conclusion:EFM with IQ demodulation significantly reduces false FHR doubling and halving,with an efficacy similar to that of internal FHR monitoring.展开更多
在电池管理系统中,二阶Thevenin等效电路模型是一种广泛应用的锂离子电池模型,合理的RC环节可以准确地描述电池的动态特性。电池模型的具体参数一般通过递推最小二乘法(recursive least square,RLS)在特定工况下辨识得到。直接采用RLS...在电池管理系统中,二阶Thevenin等效电路模型是一种广泛应用的锂离子电池模型,合理的RC环节可以准确地描述电池的动态特性。电池模型的具体参数一般通过递推最小二乘法(recursive least square,RLS)在特定工况下辨识得到。直接采用RLS算法进行参数辨识通常无法得到2个有效的RC环节参数,使得电池模型精度与适用性存在一定局限性。针对该问题,文中设计一种新型复合参数辨识工况,并基于此工况提出一种融合约束因子的递推最小二乘法用于电池建模。该方案同时参考2种具有代表性的工况数据,可同时获得SOC-OCV曲线及各荷电状态(stateofcharge,SOC)下电池模型的参数。经验证,该方案构造的电池模型在全SOC周期内,对不同电流的工况适应性较强,SOC估算精度较高。展开更多
文摘流化床反应器(Fluidized bed reactor,FBR)是以液相和固相的两相混合为特征,固相颗粒通过向下或向上的循环流实现流态化的一类生物反应器,在废水处理领域有较好的发展前景.本文主要介绍了FBR的研究现状,重点综述了FBR的新发展,包括分离固体产物、逆流流化床、与生物膜结合、与各种生物电化学系统结合以及厌氧-好氧工艺组合等新方向.
基金partially supported by the National Natural Science Foundation of China(NSFC)(Nos.62375087,12374304,U1609219,and 62235014)the NSFC Development of National Major Scientific Research Instrument(No.61927816)+3 种基金the Mobility Programme of the Sino-German(No.M-0296)the Introduced Innovative Team Project of Guangdong Pearl River Talents Program(No.2021ZT09Z109)the Natural Science Foundation of Guangdong Province(No.2021B1515020074)the Science and Technology Project of Guangdong(No.2020B1212060002)。
文摘We report a high-stability ultrafast ultraviolet(UV)laser source at 352 nm by exploring an all-fiber,all-polarizationmaintaining(all-PM),Yb-doped femtosecond fiber laser at 1060 nm.The output power,pulse width,and optical spectrum width of the fiber laser are 6 W,244 fs,and 17.5 nm,respectively.The UV ultrashort pulses at a repetition rate of 28.9 MHz are generated by leveraging single-pass second-harmonic generation in a 1.3-mm-long BiB_(3)O_(6)(BIBO)and sum frequency generation in a 5.1-mm-long BIBO.The maximum UV output power is 596 mW.The root mean square error of the output power of UV pulses is 0.54%.This laser,with promising stability,is expected to be a nice source for frontier applications in the UV wavelength window.
基金National Natural Science Foundation of China(Grant No.52078107).
文摘This research interprets the background of Jinzhou section of the Peking-Mukden Railway,and puts forward 65 heritages as cases based on the scope definition and investigation.After the data collection,processing,and visualization,the database composed of 9 sub-databases,with B/S architecture mode,is constructed based on SQL server platform.The ArcGIS tool is used to analyze the distribution of the heritages,including spatial distribution characteristics,spatial agglomeration,and spatial equilibrium.“Image and model information database”and“text attribute information database”is used to analyze the architectural ontology features.The conclusions are drawn as follows:1)The integral distribution has the characteristics of“cohesion”,while the 5 medium types of heritages show obvious and different directions.2)The overall pattern of spatial agglomeration is characterized by high cohesion with a single high agglomeration point as the core.The low agglomeration area shows a point-line-point pattern.3)The integral heritages and three main types of buildings differ in distribution,and the equilibrium is low.The architectural ontology analysis shows that the image information can be used as the basis for ontology characteristics analysis,architectural form and style judgment,and architectural functional space analysis.
基金NSFC Development of National Major Scientific Research Instrument(61927816)the Introduced Innovative Team Project of Guangdong Pearl River Talents Program(2021ZT09Z109)+6 种基金the Natural Science Foundation of Guangdong Province(2021B1515020074)the Mobility Programme of the Sino-German(M-0296)the Double First Class Initiative(D6211170)the Guangdong Key Research and Development Program(2018B090904003)the National Natural Science Foundation of China(NSFC)(U1609219)the Science and Technology Project of Guangdong(2020B1212060002)the Key R&D Program of Guangzhou(202007020003).
文摘In this work,we present a high-power,high-repetition-rate,all-fiber femtosecond laser system operating at 1.5μm.This all-fiber laser system can deliver femtosecond pulses at a fundamental repetition rate of 10.6 GHz with an average output power of 106.4 W–the highest average power reported so far from an all-fiber femtosecond laser at 1.5μm,to the best of our knowledge.By utilizing the soliton-effect-based pulse compression effect with optimized pre-chirping dispersion,the amplified pulses are compressed to 239 fs in an all-fiber configuration.Empowered by such a high-power ultrafast fiber laser system,we further explore the nonlinear interaction among transverse modes LP01,LP11 and LP21 that are expected to potentially exist in fiber laser systems using large-mode-area fibers.The intermodal modulational instability is theoretically investigated and subsequently identified in our experiments.Such a high-power all-fiber ultrafast laser without bulky free-space optics is anticipated to be a promising laser source for applications that specifically require compact and robust operation.
基金Shenzhen Science and Technology Innovation Commission(JCYJ20180228162311024)。
文摘Objective:To investigate the efficacy of in-phase and quadrature(IQ)demodulation in electronic fetal heart rate monitoring(EFM)to reduce false reports of fetal heart rate(FHR)doubling or halving.Methods:This is a prospective cohort study.A total of 263 full-term pregnant women who delivered at Peking University Shenzhen Hospital between August 2019 and July 2020 were prospectively enrolled in the study.FHR monitoring began when the cervix was dilated to 2-3 cm and continued until delivery.Raw fetal Doppler audio signals and internal and external cardiotocography curves from internal electrode monitoring,EFM with conventional demodulation(external),and EFM with IQ demodulation(external)were acquired to compare FHR doubling and halving time.In cohort 1,FHR was compared between IQ demodulation and conventional demodulation.In cohort 2,FHR was compared between IQ demodulation,conventional demodulation,and internal FHR monitoring.Count data were statistically analyzed using the Chi-squared test,and measurement data were statistically analyzed usingt-test for correlation coefficients,and Bland-Altman analysis for concordance ranges.Results:To compare IQ demodulation and conventional demodulation,225 pregnant women were monitored for a total of 835,870 seconds.The beat-to-beat interval of FHRs in raw fetal Doppler audio signals was used as the reference.The results showed a doubling time of 3401 seconds(0.407%,3401/835,870)and a halving time of 2918 seconds(0.349%,2918/835,870)with conventional demodulation,compared to 241 seconds(0.029%,241/835,870)and 589 seconds(0.070%,589/835,870),respectively,with IQ demodulation.IQ demodulation reduced FHR doubling by approximately 93%(3160/3401)and FHR halving by approximately 80%(2329/2918)compared to conventional demodulation(P<0.01).Conclusion:EFM with IQ demodulation significantly reduces false FHR doubling and halving,with an efficacy similar to that of internal FHR monitoring.
文摘在电池管理系统中,二阶Thevenin等效电路模型是一种广泛应用的锂离子电池模型,合理的RC环节可以准确地描述电池的动态特性。电池模型的具体参数一般通过递推最小二乘法(recursive least square,RLS)在特定工况下辨识得到。直接采用RLS算法进行参数辨识通常无法得到2个有效的RC环节参数,使得电池模型精度与适用性存在一定局限性。针对该问题,文中设计一种新型复合参数辨识工况,并基于此工况提出一种融合约束因子的递推最小二乘法用于电池建模。该方案同时参考2种具有代表性的工况数据,可同时获得SOC-OCV曲线及各荷电状态(stateofcharge,SOC)下电池模型的参数。经验证,该方案构造的电池模型在全SOC周期内,对不同电流的工况适应性较强,SOC估算精度较高。
