This paper, first, presents the main points of national policies and regulations, and a series of technical standards concerning legal metrological units, and bries the importance and urgency of using legal metrologic...This paper, first, presents the main points of national policies and regulations, and a series of technical standards concerning legal metrological units, and bries the importance and urgency of using legal metrological unit in the seismological system. Secondly, it examined the present situation in using legal metrological unit by checking six selected kinds of Seismological periodicals against national standard and provided in the form of tables typical error-correcting examples in using legal metrological unit for the responsibles (authors) and editorial departments.Finally,based on statistic, it analysed the causes for the existing problems and offered proposals for emphasizing the use of legal metrological units in the seismological system.展开更多
The line width(often synonymously used for critical dimension,CD)is a crucial parameter in integrated circuits.To accurately control CD values in manufacturing,a reasonable CD reference material is required to calibra...The line width(often synonymously used for critical dimension,CD)is a crucial parameter in integrated circuits.To accurately control CD values in manufacturing,a reasonable CD reference material is required to calibrate the corresponding instruments.We develop a new reference material with nominal CDs of 160 nm,80 nm,and 40 nm.The line features are investigated based on the metrological scanning electron microscope which is developed by the National Institute of Metrology(NIM)in China.Also,we propose a new characterization method for the precise measurement of CD values.After filtering and leveling the intensity profiles,the line features are characterized by the combination model of the Gaussian and Lorentz functions.The left and right edges of CD are automatically extracted with the profile decomposition and k-means algorithm.Then the width of the two edges at the half intensity position is regarded as the standard CD value.Finally,the measurement results are evaluated in terms of the sample,instrument,algorithm,and repeatability.The experiments indicate efficiency of the proposed method which can be easily applied in practice to accurately characterize CDs.展开更多
This Study investigated the effect of metrological factors variations between eastern and western foothills on olive oil quality in northern West Bank. Samples were collected from two villages: Assera A1 Shamalia (l...This Study investigated the effect of metrological factors variations between eastern and western foothills on olive oil quality in northern West Bank. Samples were collected from two villages: Assera A1 Shamalia (locates on Western foothills) and Bet Dagan (Locates on Eastern foothills). Differences in metrological factors and harvesting times between the two villages cause differences in olive oil quality and higher content of stigmastadiene in Bet Dagan than Assera olive oil. The higher monthly averages of minimum and maximum temperatures of Bet Dagan cause the increase of Stigmastadiene content of olive oil. While the higher amount of precipitation in Assera; cause higher quality and quantity of produced olive oil in Assera compared to Bet Dagan. The lower relative humidity and longer day hours; in Assera village enhances higher amounts of olive oil accumulation and better quality as this is the favorable conditions for olive oil formation. The compression between Cuba, Crete, Spain and Italy olive oil quality with Palestinian olive oil quality, we found that Palestinian olive oil shows good competition quality parameters for acidity and peroxide values according to the international olive oil council limits compared with these countries olive oil acidity and peroxide values.展开更多
With the rapid development of China’s economy and society,under the existing economic system,measurement work is of great significance to promote market development and improve people’s living standards.The quality ...With the rapid development of China’s economy and society,under the existing economic system,measurement work is of great significance to promote market development and improve people’s living standards.The quality evaluation of testing work is an important means to ensure the accuracy of measurement.Based on the analysis of several factors affecting the quality of measurement work,this paper takes the ionizing radiation monitoring quality as an example,and makes a concrete exposition on the evaluation and analysis of the quality of metrological verification work.展开更多
It is well known that the solar tracking systems can increase the efficiency of the photovoltaic (PV) panel by about 30 percent. However, these systems require precise control of their components, mainly of the equipm...It is well known that the solar tracking systems can increase the efficiency of the photovoltaic (PV) panel by about 30 percent. However, these systems require precise control of their components, mainly of the equipment’s used for the measurement of energy. In this paper, a metrology analysis is conducted, through of the results obtained by Sunflower prototype. The Sunflower is a solar tracking system developed by H. J. Loschi. A tracking system through a microcontrolled timing logic, sending commands to a linear actuator that moves the system. The deductions, based on in research trials, confirms that the Sunflower prototype is more efficient in relation to fixed PV panels, it is possible to observe the difference in the efficiency of 31%, with a variation of ±0.8% (that depends the solar irradiation). The main purpose of this paper is to attest to the quality of the measurements carried out during the performance tests of the Sunflower prototype, evaluating the uncertainty of measurements collected through the measurements equipment, and, introducing methods to minimize uncertainties of measurement equipment in the PV systems.展开更多
Using scientific metrological method,this paper analyzed all literature published by top 4 marketing periodicals( JCR,JM,JMR,and MS) in 2009- 2013. It is intended to find out hot issues and frontier topics of current ...Using scientific metrological method,this paper analyzed all literature published by top 4 marketing periodicals( JCR,JM,JMR,and MS) in 2009- 2013. It is intended to find out hot issues and frontier topics of current marketing research through cluster analysis of key words,get to know cooperation and exchange of organizations through analysis of organization cooperative network,explore new topics of marketing researches with the aid of analysis of abrupt change words,and explore evolution path and development rules of marketing researches through co-citation network analysis.展开更多
As the most precise viscous vacuum gauge,the spinning rotor gauge is widely used in the aerospace,nuclear,semiconductor,and other fields because of its excellent accuracy and chemical inertness.Herein,a metrological-g...As the most precise viscous vacuum gauge,the spinning rotor gauge is widely used in the aerospace,nuclear,semiconductor,and other fields because of its excellent accuracy and chemical inertness.Herein,a metrological-grade spinning rotor vacuum gauge is developed,and its performance is evaluated.It can be used for international comparison of vacuum standards and construction of national vacuum measurement traceability and transmission systems.This paper presents the design of a single-degree-of-freedom permanent magnet-biased rotor suspension system,a high-speed rotary stepper drive system,a rotational angular velocity determination system,a lateral damping system,and a transducer in detail.The change in residual drag is less than 0.49%after 50 minutes of start-up.There is good consistency and linearity in the range of 9.1727×10^(−5)Pa to 1.2081 Pa.展开更多
Objective To provide new ideas for the effective treatment of many serious diseases and to solve many major medical problems faced by mankind.Methods In this paper,the invention patents in the field of stem cells in C...Objective To provide new ideas for the effective treatment of many serious diseases and to solve many major medical problems faced by mankind.Methods In this paper,the invention patents in the field of stem cells in China from 2010 to 2020 were taken as the research object,and the technology status quo in the field of stem cells was analyzed to predict the future development direction through quantitative analysis method.Results and Conclusion The development of stem cell technology in China is in a period of growth with great potential.Therefore,it is necessary to strengthen the ability of Chinese universities to combine production,education and research.Nowadays,the hotspots in stem cell technology are using culture medium to improve cell proliferation ability,production efficiency,and to induce differentiated cells.Meanwhile,the production efficiency of embryonic stem cells should be improved,and the immunomodulatory effect of embryonic stem cells can be exerted to screen drugs.Besides,the function of hematopoietic stem cells should be enhanced and apply mesenchymal cells in therapy.Since the potential technological gaps are the improvement of therapy,induced differentiation and efficiency of pluripotent stem cells,the improvement of progenitor cell proliferation and the control of cost,we should strengthen R&D investment in culture medium,embryonic stem cells and other technical fields,and achieve the purpose of reducing R&D costs and improving R&D efficiency.展开更多
Atomic nonlinear interferometry has wide applications in quantum metrology and quantum information science.Here we propose a nonlinear time-reversal interferometry scheme with high robustness and metrological gain bas...Atomic nonlinear interferometry has wide applications in quantum metrology and quantum information science.Here we propose a nonlinear time-reversal interferometry scheme with high robustness and metrological gain based on the spin squeezing generated by arbitrary quadratic collective-spin interaction,which could be described by the Lipkin–Meshkov–Glick(LMG)model.We optimize the squeezing process,encoding process,and anti-squeezing process,finding that the two particular cases of the LMG model,one-axis twisting and two-axis twisting outperform in robustness and precision,respectively.Moreover,we propose a Floquet driving method to realize equivalent time reverse in the atomic system,which leads to high performance in precision,robustness,and operability.Our study sets a benchmark for achieving high precision and high robustness in atomic nonlinear interferometry.展开更多
Recently,deep learning has yielded transformative success across optics and photonics,especially in optical metrology.Deep neural networks (DNNs) with a fully convolutional architecture (e.g.,U-Net and its derivatives...Recently,deep learning has yielded transformative success across optics and photonics,especially in optical metrology.Deep neural networks (DNNs) with a fully convolutional architecture (e.g.,U-Net and its derivatives) have been widely implemented in an end-to-end manner to accomplish various optical metrology tasks,such as fringe denoising,phase unwrapping,and fringe analysis.However,the task of training a DNN to accurately identify an image-to-image transform from massive input and output data pairs seems at best naive,as the physical laws governing the image formation or other domain expertise pertaining to the measurement have not yet been fully exploited in current deep learning practice.To this end,we introduce a physics-informed deep learning method for fringe pattern analysis (PI-FPA) to overcome this limit by integrating a lightweight DNN with a learning-enhanced Fourier transform profilometry (Le FTP) module.By parameterizing conventional phase retrieval methods,the Le FTP module embeds the prior knowledge in the network structure and the loss function to directly provide reliable phase results for new types of samples,while circumventing the requirement of collecting a large amount of high-quality data in supervised learning methods.Guided by the initial phase from Le FTP,the phase recovery ability of the lightweight DNN is enhanced to further improve the phase accuracy at a low computational cost compared with existing end-to-end networks.Experimental results demonstrate that PI-FPA enables more accurate and computationally efficient single-shot phase retrieval,exhibiting its excellent generalization to various unseen objects during training.The proposed PI-FPA presents that challenging issues in optical metrology can be potentially overcome through the synergy of physics-priors-based traditional tools and data-driven learning approaches,opening new avenues to achieve fast and accurate single-shot 3D imaging.展开更多
Holevo bound plays an important role in quantum metrology as it sets the ultimate limit for multi-parameter estimations,which can be asymptotically achieved.Except for some trivial cases,the Holevo bound is implicitly...Holevo bound plays an important role in quantum metrology as it sets the ultimate limit for multi-parameter estimations,which can be asymptotically achieved.Except for some trivial cases,the Holevo bound is implicitly defined and formulated with the help of weight matrices.Here we report the first instance of an intrinsic Holevo bound,namely,without any reference to weight matrices,in a nontrivial case.Specifically,we prove that the Holevo bound for estimating two parameters of a qubit is equivalent to the joint constraint imposed by two quantum Cramér–Rao bounds corresponding to symmetric and right logarithmic derivatives.This weightless form of Holevo bound enables us to determine the precise range of independent entries of the mean-square error matrix,i.e.,two variances and one covariance that quantify the precisions of the estimation,as illustrated by different estimation models.Our result sheds some new light on the relations between the Holevo bound and quantum Cramer–Rao bounds.Possible generalizations are discussed.展开更多
We present a quantitative measurement of the horizontal component of the microwave magnetic field of a coplanar waveguide using a quantum diamond probe in fiber format.The measurement results are compared in detail wi...We present a quantitative measurement of the horizontal component of the microwave magnetic field of a coplanar waveguide using a quantum diamond probe in fiber format.The measurement results are compared in detail with simulation,showing a good consistence.Further simulation shows fiber diamond probe brings negligible disturbance to the field under measurement compared to bulk diamond.This method will find important applications ranging from electromagnetic compatibility test and failure analysis of high frequency and high complexity integrated circuits.展开更多
Quantum multi-parameter estimation has recently attracted increased attention due to its wide applications, with a primary goal of designing high-precision measurement schemes for unknown parameters. While existing re...Quantum multi-parameter estimation has recently attracted increased attention due to its wide applications, with a primary goal of designing high-precision measurement schemes for unknown parameters. While existing research has predominantly concentrated on time-independent Hamiltonians, little has been known about quantum multi-parameter estimation for time-dependent Hamiltonians due to the complexity of quantum dynamics. This work bridges the gap by investigating the precision limit of multi-parameter quantum estimation for a qubit in an oscillating magnetic field model with multiple unknown frequencies. As the well-known quantum Cramer–Rao bound is generally unattainable due to the potential incompatibility between the optimal measurements for different parameters, we use the most informative bound instead which is always attainable and equivalent to the Holevo bound in the asymptotic limit. Moreover, we apply additional Hamiltonian to the system to engineer the dynamics of the qubit. By utilizing the quasi-Newton method, we explore the optimal schemes to attain the highest precision for the unknown frequencies of the magnetic field, including the simultaneous optimization of initial state preparation, the control Hamiltonian and the final measurement. The results indicate that the optimization can yield much higher precisions for the field frequencies than those without the optimizations. Finally,we study the robustness of the optimal control scheme with respect to the fluctuation of the interested frequencies, and the optimized scheme exhibits superior robustness to the scenario without any optimization.展开更多
The aim of this study is to evaluate the uncertainty of 2πα and 2πβ surface emission rates using the windowless multiwire proportional counter method.This study used the Monte Carlo method (MCM) to validate the co...The aim of this study is to evaluate the uncertainty of 2πα and 2πβ surface emission rates using the windowless multiwire proportional counter method.This study used the Monte Carlo method (MCM) to validate the conventional Guide to the Expression of Uncertainty in Measurement (GUM) method.A dead time measurement model for the two-source method was established based on the characteristics of a single-channel measurement system,and the voltage threshold correction factor measurement function was indirectly obtained by fitting the threshold correction curve.The uncertainty in the surface emission rate was calculated using the GUM method and the law of propagation of uncertainty.The MCM provided clear definitions for each input quantity and its uncertainty distribution,and the simulation training was realized with a complete and complex mathematical model.The results of the surface emission rate uncertainty evaluation for four radioactive plane sources using both methods showed the uncertainty’s consistency E_(n)<0.070 for the comparison of each source,and the uncertainty results of the GUM were all lower than those of the MCM.However,the MCM has a more objective evaluation process and can serve as a validation tool for GUM results.展开更多
Action plan on establishing standards and metrology system for dual carbon goals released Recently,the National Development and Reform Commission,the State Administration for Market Regulation(SAMR),and the Ministry o...Action plan on establishing standards and metrology system for dual carbon goals released Recently,the National Development and Reform Commission,the State Administration for Market Regulation(SAMR),and the Ministry of Ecology and Environment jointly issued the Action Plan on Further Strengthening the Construction of Standards and Metrology System for Carbon Peak and Neutrality(2024-2025).展开更多
Radiotherapy is the most widely applied oncologic treatment modality utilizing ionizing radiation. A high degree of accuracy, reliability and reproducibility is required for a successful treatment outcome. Measurement...Radiotherapy is the most widely applied oncologic treatment modality utilizing ionizing radiation. A high degree of accuracy, reliability and reproducibility is required for a successful treatment outcome. Measurement using ionization chamber is a prerequisite for absorbed dose determination for external beam radiotherapy. Calibration coefficient is expressed in terms of air kerma and absorbed dose to water traceable to Secondary Standards Dosimetry Laboratory. The objective of this work was to evaluate the level of accuracy of ionization chamber used for clinical radiotherapy beam determination. Measurement and accuracy determination were carried out according to IAEA TRS 398 protocol. Clinical farmers type ionization chamber measurement and National Reference standard from Secondary Standards Dosimetry Laboratory were both exposed to cobalt-60 beam and measurement results compared under the same environmental conditions. The accuracy level between National Reference Standard and clinical radiotherapy standard was found to be −1.92% and −2.02% for air kerma and absorbed dose to water respectively. To minimize the effect of error and maximize therapeutic dose during treatment in order to achieve required clinical outcome, calibration factor was determined for air kerma (Nk) as 49.7 mGy/nC and absorbed dose to water ND, as 52.9 mGy/nC. The study established that radiotherapy beam measurement chain is prone to errors. Hence there is a need to independently verify the accuracy of radiation dose to ensure precision of dose delivery. The errors must be accounted for during clinical planning by factoring in calibration factor to minimize the systematic errors during treatment, and thereby providing enough room to achieve ±5% dose delivery to tumor target as recommended by ICRU.展开更多
文摘This paper, first, presents the main points of national policies and regulations, and a series of technical standards concerning legal metrological units, and bries the importance and urgency of using legal metrological unit in the seismological system. Secondly, it examined the present situation in using legal metrological unit by checking six selected kinds of Seismological periodicals against national standard and provided in the form of tables typical error-correcting examples in using legal metrological unit for the responsibles (authors) and editorial departments.Finally,based on statistic, it analysed the causes for the existing problems and offered proposals for emphasizing the use of legal metrological units in the seismological system.
基金supported by the National Key Research and Development Program of China(Grant No.2020YFF0218403)the Basic Scientific Research Operating Fund of NIM(Grant No.AKYZD2007-1)。
文摘The line width(often synonymously used for critical dimension,CD)is a crucial parameter in integrated circuits.To accurately control CD values in manufacturing,a reasonable CD reference material is required to calibrate the corresponding instruments.We develop a new reference material with nominal CDs of 160 nm,80 nm,and 40 nm.The line features are investigated based on the metrological scanning electron microscope which is developed by the National Institute of Metrology(NIM)in China.Also,we propose a new characterization method for the precise measurement of CD values.After filtering and leveling the intensity profiles,the line features are characterized by the combination model of the Gaussian and Lorentz functions.The left and right edges of CD are automatically extracted with the profile decomposition and k-means algorithm.Then the width of the two edges at the half intensity position is regarded as the standard CD value.Finally,the measurement results are evaluated in terms of the sample,instrument,algorithm,and repeatability.The experiments indicate efficiency of the proposed method which can be easily applied in practice to accurately characterize CDs.
文摘This Study investigated the effect of metrological factors variations between eastern and western foothills on olive oil quality in northern West Bank. Samples were collected from two villages: Assera A1 Shamalia (locates on Western foothills) and Bet Dagan (Locates on Eastern foothills). Differences in metrological factors and harvesting times between the two villages cause differences in olive oil quality and higher content of stigmastadiene in Bet Dagan than Assera olive oil. The higher monthly averages of minimum and maximum temperatures of Bet Dagan cause the increase of Stigmastadiene content of olive oil. While the higher amount of precipitation in Assera; cause higher quality and quantity of produced olive oil in Assera compared to Bet Dagan. The lower relative humidity and longer day hours; in Assera village enhances higher amounts of olive oil accumulation and better quality as this is the favorable conditions for olive oil formation. The compression between Cuba, Crete, Spain and Italy olive oil quality with Palestinian olive oil quality, we found that Palestinian olive oil shows good competition quality parameters for acidity and peroxide values according to the international olive oil council limits compared with these countries olive oil acidity and peroxide values.
文摘With the rapid development of China’s economy and society,under the existing economic system,measurement work is of great significance to promote market development and improve people’s living standards.The quality evaluation of testing work is an important means to ensure the accuracy of measurement.Based on the analysis of several factors affecting the quality of measurement work,this paper takes the ionizing radiation monitoring quality as an example,and makes a concrete exposition on the evaluation and analysis of the quality of metrological verification work.
文摘It is well known that the solar tracking systems can increase the efficiency of the photovoltaic (PV) panel by about 30 percent. However, these systems require precise control of their components, mainly of the equipment’s used for the measurement of energy. In this paper, a metrology analysis is conducted, through of the results obtained by Sunflower prototype. The Sunflower is a solar tracking system developed by H. J. Loschi. A tracking system through a microcontrolled timing logic, sending commands to a linear actuator that moves the system. The deductions, based on in research trials, confirms that the Sunflower prototype is more efficient in relation to fixed PV panels, it is possible to observe the difference in the efficiency of 31%, with a variation of ±0.8% (that depends the solar irradiation). The main purpose of this paper is to attest to the quality of the measurements carried out during the performance tests of the Sunflower prototype, evaluating the uncertainty of measurements collected through the measurements equipment, and, introducing methods to minimize uncertainties of measurement equipment in the PV systems.
基金Supported by Project of National Natural Science Foundation(71273102)Fundamental Research Funds for the Central Universities(2012RW004)
文摘Using scientific metrological method,this paper analyzed all literature published by top 4 marketing periodicals( JCR,JM,JMR,and MS) in 2009- 2013. It is intended to find out hot issues and frontier topics of current marketing research through cluster analysis of key words,get to know cooperation and exchange of organizations through analysis of organization cooperative network,explore new topics of marketing researches with the aid of analysis of abrupt change words,and explore evolution path and development rules of marketing researches through co-citation network analysis.
文摘As the most precise viscous vacuum gauge,the spinning rotor gauge is widely used in the aerospace,nuclear,semiconductor,and other fields because of its excellent accuracy and chemical inertness.Herein,a metrological-grade spinning rotor vacuum gauge is developed,and its performance is evaluated.It can be used for international comparison of vacuum standards and construction of national vacuum measurement traceability and transmission systems.This paper presents the design of a single-degree-of-freedom permanent magnet-biased rotor suspension system,a high-speed rotary stepper drive system,a rotational angular velocity determination system,a lateral damping system,and a transducer in detail.The change in residual drag is less than 0.49%after 50 minutes of start-up.There is good consistency and linearity in the range of 9.1727×10^(−5)Pa to 1.2081 Pa.
文摘Objective To provide new ideas for the effective treatment of many serious diseases and to solve many major medical problems faced by mankind.Methods In this paper,the invention patents in the field of stem cells in China from 2010 to 2020 were taken as the research object,and the technology status quo in the field of stem cells was analyzed to predict the future development direction through quantitative analysis method.Results and Conclusion The development of stem cell technology in China is in a period of growth with great potential.Therefore,it is necessary to strengthen the ability of Chinese universities to combine production,education and research.Nowadays,the hotspots in stem cell technology are using culture medium to improve cell proliferation ability,production efficiency,and to induce differentiated cells.Meanwhile,the production efficiency of embryonic stem cells should be improved,and the immunomodulatory effect of embryonic stem cells can be exerted to screen drugs.Besides,the function of hematopoietic stem cells should be enhanced and apply mesenchymal cells in therapy.Since the potential technological gaps are the improvement of therapy,induced differentiation and efficiency of pluripotent stem cells,the improvement of progenitor cell proliferation and the control of cost,we should strengthen R&D investment in culture medium,embryonic stem cells and other technical fields,and achieve the purpose of reducing R&D costs and improving R&D efficiency.
基金Project supported by the National Key R&D Program of China (Grant No.2023YFA1407600)the National Natural Science Foundation of China (Grant Nos.12275145,92050110,91736106,11674390,and 91836302)。
文摘Atomic nonlinear interferometry has wide applications in quantum metrology and quantum information science.Here we propose a nonlinear time-reversal interferometry scheme with high robustness and metrological gain based on the spin squeezing generated by arbitrary quadratic collective-spin interaction,which could be described by the Lipkin–Meshkov–Glick(LMG)model.We optimize the squeezing process,encoding process,and anti-squeezing process,finding that the two particular cases of the LMG model,one-axis twisting and two-axis twisting outperform in robustness and precision,respectively.Moreover,we propose a Floquet driving method to realize equivalent time reverse in the atomic system,which leads to high performance in precision,robustness,and operability.Our study sets a benchmark for achieving high precision and high robustness in atomic nonlinear interferometry.
基金funded by National Key Research and Development Program of China (2022YFB2804603,2022YFB2804604)National Natural Science Foundation of China (62075096,62205147,U21B2033)+7 种基金China Postdoctoral Science Foundation (2023T160318,2022M711630,2022M721619)Jiangsu Funding Program for Excellent Postdoctoral Talent (2022ZB254)The Leading Technology of Jiangsu Basic Research Plan (BK20192003)The“333 Engineering”Research Project of Jiangsu Province (BRA2016407)The Jiangsu Provincial“One belt and one road”innovation cooperation project (BZ2020007)Open Research Fund of Jiangsu Key Laboratory of Spectral Imaging&Intelligent Sense (JSGP202105)Fundamental Research Funds for the Central Universities (30922010405,30921011208,30920032101,30919011222)National Major Scientific Instrument Development Project (62227818).
文摘Recently,deep learning has yielded transformative success across optics and photonics,especially in optical metrology.Deep neural networks (DNNs) with a fully convolutional architecture (e.g.,U-Net and its derivatives) have been widely implemented in an end-to-end manner to accomplish various optical metrology tasks,such as fringe denoising,phase unwrapping,and fringe analysis.However,the task of training a DNN to accurately identify an image-to-image transform from massive input and output data pairs seems at best naive,as the physical laws governing the image formation or other domain expertise pertaining to the measurement have not yet been fully exploited in current deep learning practice.To this end,we introduce a physics-informed deep learning method for fringe pattern analysis (PI-FPA) to overcome this limit by integrating a lightweight DNN with a learning-enhanced Fourier transform profilometry (Le FTP) module.By parameterizing conventional phase retrieval methods,the Le FTP module embeds the prior knowledge in the network structure and the loss function to directly provide reliable phase results for new types of samples,while circumventing the requirement of collecting a large amount of high-quality data in supervised learning methods.Guided by the initial phase from Le FTP,the phase recovery ability of the lightweight DNN is enhanced to further improve the phase accuracy at a low computational cost compared with existing end-to-end networks.Experimental results demonstrate that PI-FPA enables more accurate and computationally efficient single-shot phase retrieval,exhibiting its excellent generalization to various unseen objects during training.The proposed PI-FPA presents that challenging issues in optical metrology can be potentially overcome through the synergy of physics-priors-based traditional tools and data-driven learning approaches,opening new avenues to achieve fast and accurate single-shot 3D imaging.
基金Project supported by the Key-Area Research and Development Program of Guangdong Province of China(Grant Nos.2020B0303010001 and SIQSE202104).
文摘Holevo bound plays an important role in quantum metrology as it sets the ultimate limit for multi-parameter estimations,which can be asymptotically achieved.Except for some trivial cases,the Holevo bound is implicitly defined and formulated with the help of weight matrices.Here we report the first instance of an intrinsic Holevo bound,namely,without any reference to weight matrices,in a nontrivial case.Specifically,we prove that the Holevo bound for estimating two parameters of a qubit is equivalent to the joint constraint imposed by two quantum Cramér–Rao bounds corresponding to symmetric and right logarithmic derivatives.This weightless form of Holevo bound enables us to determine the precise range of independent entries of the mean-square error matrix,i.e.,two variances and one covariance that quantify the precisions of the estimation,as illustrated by different estimation models.Our result sheds some new light on the relations between the Holevo bound and quantum Cramer–Rao bounds.Possible generalizations are discussed.
基金Project supported by the National Key Research and Development Program of China (Grant No.2021YFB2012600)。
文摘We present a quantitative measurement of the horizontal component of the microwave magnetic field of a coplanar waveguide using a quantum diamond probe in fiber format.The measurement results are compared in detail with simulation,showing a good consistence.Further simulation shows fiber diamond probe brings negligible disturbance to the field under measurement compared to bulk diamond.This method will find important applications ranging from electromagnetic compatibility test and failure analysis of high frequency and high complexity integrated circuits.
基金Project supported by the National Natural Science Foundation of China (Grant No. 12075323)。
文摘Quantum multi-parameter estimation has recently attracted increased attention due to its wide applications, with a primary goal of designing high-precision measurement schemes for unknown parameters. While existing research has predominantly concentrated on time-independent Hamiltonians, little has been known about quantum multi-parameter estimation for time-dependent Hamiltonians due to the complexity of quantum dynamics. This work bridges the gap by investigating the precision limit of multi-parameter quantum estimation for a qubit in an oscillating magnetic field model with multiple unknown frequencies. As the well-known quantum Cramer–Rao bound is generally unattainable due to the potential incompatibility between the optimal measurements for different parameters, we use the most informative bound instead which is always attainable and equivalent to the Holevo bound in the asymptotic limit. Moreover, we apply additional Hamiltonian to the system to engineer the dynamics of the qubit. By utilizing the quasi-Newton method, we explore the optimal schemes to attain the highest precision for the unknown frequencies of the magnetic field, including the simultaneous optimization of initial state preparation, the control Hamiltonian and the final measurement. The results indicate that the optimization can yield much higher precisions for the field frequencies than those without the optimizations. Finally,we study the robustness of the optimal control scheme with respect to the fluctuation of the interested frequencies, and the optimized scheme exhibits superior robustness to the scenario without any optimization.
文摘The aim of this study is to evaluate the uncertainty of 2πα and 2πβ surface emission rates using the windowless multiwire proportional counter method.This study used the Monte Carlo method (MCM) to validate the conventional Guide to the Expression of Uncertainty in Measurement (GUM) method.A dead time measurement model for the two-source method was established based on the characteristics of a single-channel measurement system,and the voltage threshold correction factor measurement function was indirectly obtained by fitting the threshold correction curve.The uncertainty in the surface emission rate was calculated using the GUM method and the law of propagation of uncertainty.The MCM provided clear definitions for each input quantity and its uncertainty distribution,and the simulation training was realized with a complete and complex mathematical model.The results of the surface emission rate uncertainty evaluation for four radioactive plane sources using both methods showed the uncertainty’s consistency E_(n)<0.070 for the comparison of each source,and the uncertainty results of the GUM were all lower than those of the MCM.However,the MCM has a more objective evaluation process and can serve as a validation tool for GUM results.
文摘Action plan on establishing standards and metrology system for dual carbon goals released Recently,the National Development and Reform Commission,the State Administration for Market Regulation(SAMR),and the Ministry of Ecology and Environment jointly issued the Action Plan on Further Strengthening the Construction of Standards and Metrology System for Carbon Peak and Neutrality(2024-2025).
文摘Radiotherapy is the most widely applied oncologic treatment modality utilizing ionizing radiation. A high degree of accuracy, reliability and reproducibility is required for a successful treatment outcome. Measurement using ionization chamber is a prerequisite for absorbed dose determination for external beam radiotherapy. Calibration coefficient is expressed in terms of air kerma and absorbed dose to water traceable to Secondary Standards Dosimetry Laboratory. The objective of this work was to evaluate the level of accuracy of ionization chamber used for clinical radiotherapy beam determination. Measurement and accuracy determination were carried out according to IAEA TRS 398 protocol. Clinical farmers type ionization chamber measurement and National Reference standard from Secondary Standards Dosimetry Laboratory were both exposed to cobalt-60 beam and measurement results compared under the same environmental conditions. The accuracy level between National Reference Standard and clinical radiotherapy standard was found to be −1.92% and −2.02% for air kerma and absorbed dose to water respectively. To minimize the effect of error and maximize therapeutic dose during treatment in order to achieve required clinical outcome, calibration factor was determined for air kerma (Nk) as 49.7 mGy/nC and absorbed dose to water ND, as 52.9 mGy/nC. The study established that radiotherapy beam measurement chain is prone to errors. Hence there is a need to independently verify the accuracy of radiation dose to ensure precision of dose delivery. The errors must be accounted for during clinical planning by factoring in calibration factor to minimize the systematic errors during treatment, and thereby providing enough room to achieve ±5% dose delivery to tumor target as recommended by ICRU.