In fundamental theories of physics, the dynamical equations all have time inversion invariance. Except for the evolution of some simple system which has realistic inverse processes, but for a slightly more complicated...In fundamental theories of physics, the dynamical equations all have time inversion invariance. Except for the evolution of some simple system which has realistic inverse processes, but for a slightly more complicated system, the evolution processes are irreversible. This is the problem of arrow of time, which is always warmly debated. In different point of view, we find there may have some conceptual misunderstanding in the controversy: 1) The realization of an inverse process does not mean the time of the system goes backward. 2) The principles of relativity and covariance are the constraints to physical laws, but not constraints to specific solutions. The equations must be covariant, but the solutions are not definitely symmetric. 3) Time is a global property of the universe, which is a measurement of the evolution process of the universe. The internal time of a matter system reflecting its internal evolution speed also takes this cosmic time as a unified background and standard of measurement. 4) The universe has a unified cosmic time T and a cosmic space related to this cosmic time. They are objective and absolute. 5) The eigensolution of a spinor is a critical state losing time concept, which responses the interaction of environment with some uncertainty, then the evolution process of the world is not uniquely determined. 6) The non-uniqueness of the evolution process means that the inverse process is absent. So for a world including spinors, the evolution is essentially irreversible. In this paper, according to the widely accepted principles and direct calculations of transformation, we reveal the misunderstandings in the usual controversy, and then give more natural and reasonable explanations for structure of space-time and arrow of time.展开更多
When we study Lorentz transformation in the framework of quantum gauge theory of gravity, we will find that the vacuum gravitational gauge field will be changed under gravitational gauge transformation, which will cha...When we study Lorentz transformation in the framework of quantum gauge theory of gravity, we will find that the vacuum gravitational gauge field will be changed under gravitational gauge transformation, which will change the structure of the physical space-time and cause clock dilation effect. The study in this paper provides us with new insights to understand the essential and intrinsic relation between special relativity and general relativity. It provides us with a new way to unify special relativity and general relativity.展开更多
FePt granular films were prepared by direct current facing-target magnetron sputtering system onto glass substrates and subsequently in-situ annealed in vacuum. Vibrating sample magnetometer, X-ray diffraction and sca...FePt granular films were prepared by direct current facing-target magnetron sputtering system onto glass substrates and subsequently in-situ annealed in vacuum. Vibrating sample magnetometer, X-ray diffraction and scanning probe microscope were applied to study the magnetic properties, microstructures, morphologies and domain structures of the samples. （FePt）27Ti73 bilayer films were fabricated at various conditions to investigate the effect of Ti on FePt grains. The results show that without Ti matrix layer, FePt films deposited onto the glass substrates are fcc disordered; with addition of Ti matrix layer, FePt/Ti films form a ternary （FePt）27Ti73 alloy possessing fcc and L10 （111） mixed texture. FePt/（FePt）27Ti73 films with perfectly ordered L10（111） structure and unique magnetic properties can be obtained at Ti thickness of 35nm and substrate temperature of 250℃. The maximum coercivity is more than 240kA/m and the squareness ratio is more than 0.9. The obtained results suggest that the granular FePt/（FePt）27Ti73 films can be applicable to ultrahigh-density magnetic recording media.展开更多
Surgical site infections(SSIs)are the most common healthcare-related infections in patients with lung cancer.Constructing a lung cancer SSI risk prediction model requires the extraction of relevant risk factors from l...Surgical site infections(SSIs)are the most common healthcare-related infections in patients with lung cancer.Constructing a lung cancer SSI risk prediction model requires the extraction of relevant risk factors from lung cancer case texts,which involves two types of text structuring tasks:attribute discrimination and attribute extraction.This article proposes a joint model,Multi-BGLC,around these two types of tasks,using bidirectional encoder representations from transformers(BERT)as the encoder and fine-tuning the decoder composed of graph convolutional neural network(GCNN)+long short-term memory(LSTM)+conditional random field(CRF)based on cancer case data.The GCNN is used for attribute discrimination,whereas the LSTM and CRF are used for attribute extraction.The experiment verified the effectiveness and accuracy of the model compared with other baseline models.展开更多
In this paper, a new observation equation of non-Gaussian frequency selective fading Bell Labs layered space time （BLAST） architecture system is proposed, which is used for frequency selective fading channels and no...In this paper, a new observation equation of non-Gaussian frequency selective fading Bell Labs layered space time （BLAST） architecture system is proposed, which is used for frequency selective fading channels and non-Gaussian noise in an application environment of BLAST system. With othogonal matrix triangularization （QR decomposition） of the channel matrix, the static observation equation of frequency selective fading BLAST system is transformed into a dynamic state space model, and then the particle filter is used for space-time layered detection. Making the full use of the finite alphabet of the digital modulation communication signal, the optimal proposal distribution can be chosen to produce particle and update the weight. Incorporated with current method of reducing error propagation, a new space-time layered detection algorithm is proposed. Simulation result shows the validity of the proposed algorithm.展开更多
Shallow surface wave methods are mostly used for investigation of the surface velocity structure in environmental and engineering geophysics in non-desert areas. For the special geological features of the Takelamagan ...Shallow surface wave methods are mostly used for investigation of the surface velocity structure in environmental and engineering geophysics in non-desert areas. For the special geological features of the Takelamagan Desert area, we use the multi-channel analysis of surface wave （MASW） method to process multi-channel shallow surface wave records to determine the near surface velocity structure in the desert area. We also process, analyze, and compare the surface waves in many-trace records extracted from the oil exploration shot gathers in the area. We show that the MASW method can determine detailed shallow velocity structure in desert areas and the many-trace records can be used to get detailed deep geological structure. The combination of the two different datasets can obtain the exact velocity structure upper 60 m depth in the survey area.展开更多
TiCoTi granular films were prepared by DC facing-target magnetron sputtering system onto glass substrates and subsequently in situ annealing in vacuum. Structural of Ti (t nm)/Co (40 nm)/Ti (t nm) films were investiga...TiCoTi granular films were prepared by DC facing-target magnetron sputtering system onto glass substrates and subsequently in situ annealing in vacuum. Structural of Ti (t nm)/Co (40 nm)/Ti (t nm) films were investigated in detail, which shows that the majority Co nanograins are formed as the hexagonal-close-packed (HCP) structure. Vibrating sample magnetometer (VSM) and scanning probe microscope (SPM) were applied to study the magnetic properties, morphologies and domain structures of these samples. It has been found that the structure and magnetic properties of the Ti/Co/Ti films depend strongly on the Ti layer thickness. The out-of-plane coercivities (Hc) of the film is maximum about 78.8 kA·m-1 when t=5 nm with annealing at 300 ℃; the distributing of grains of the sample is uniformity; and the average size of particles is about 13 nm. The obtained results suggest that this system is perpendicular anisotropy and might be applicable to perpendicular magnetic recording media.展开更多
Introduction:Traditional dietary surveys are timeconsuming,and manual recording may lead to omissions.Improvement during data collection is essential to enhance accuracy of nutritional surveys.In recent years,large la...Introduction:Traditional dietary surveys are timeconsuming,and manual recording may lead to omissions.Improvement during data collection is essential to enhance accuracy of nutritional surveys.In recent years,large language models(LLMs)have been rapidly developed,which can provide text-processing functions and assist investigators in conducting dietary surveys.Methods:Thirty-eight participants from 15 families in the Huangpu and Jiading districts of Shanghai were selected.A standardized 24-hour dietary recall protocol was conducted using an intelligent recording pen that simultaneously captured audio data.These recordings were then transcribed into text.After preprocessing,we used GLM-4 for prompt engineering and chain-of-thought for collaborative reasoning,output structured data,and analyzed its integrity and consistency.Model performance was evaluated using precision and F1 scores.Results:The overall integrity rate of the LLMbased structured data reached 92.5%,and the overall consistency rate compared with manual recording was 86%.The LLM can accurately and completely recognize the names of ingredients and dining and production locations during the transcription.The LLM achieved 94%precision and an F1 score of 89.7%for the full dataset.Conclusion:LLM-based text recognition and structured data extraction can serve as effective auxiliary tools to improve efficiency and accuracy in traditional dietary surveys.With the rapid advancement of artificial intelligence,more accurate and efficient auxiliary tools can be developed for more precise and efficient data collection in nutrition research.展开更多
This paper focuses on the design of an impact-resistant protective structure for an ejection flight data recording and emergency tracking system.To ensure that the protective structure possesses excellent impact resis...This paper focuses on the design of an impact-resistant protective structure for an ejection flight data recording and emergency tracking system.To ensure that the protective structure possesses excellent impact resistance and energy absorption performance under the design constraints of light weight and miniaturization,a preliminary design of the impact-resistant protective structure is achieved by adopting a thin-walled shell with a periodic perforation pattern based on the analysis of protective theory and design principles.A parametric study of the structure through axial compression simulations indicate that the structure exhibits superior energy absorption when subjected to lower impact velocities,larger wall thicknesses,and moderate hole diameters.A multi-objective optimization for structural dimensions is conducted to maximize specific energy absorption and minimize peak crushing force.The performance of the impact-resistant structure is validated with a numerical model by analyzing the stress distribution and acceleration of the circuit board.The results show that the optimized structure reduces the peak stress by 15%and the maximum acceleration by 44%.展开更多
Fe100-xPtx(x=30at.%-60at.%) nanocomposite films were deposited on natural-oxidized Si(100) substrates by magnetron sputtering. The as-deposited films were annealed between 373 and 1073 K. In situ X-ray diffraction sho...Fe100-xPtx(x=30at.%-60at.%) nanocomposite films were deposited on natural-oxidized Si(100) substrates by magnetron sputtering. The as-deposited films were annealed between 373 and 1073 K. In situ X-ray diffraction shows that the FePt nanocomposite films undergo a phase transformation from a disordered FCC phase to an ordered L10 phase between 673 and 773 K. The coercivity is 306 kA·m-1 whiles the average grain sizes is about 10 nm in the optimized FePt alloy film sample annealed at 673 K. The adjustable coercivity and fine grain size suggest that this FePt nanocomposites system is suitable as recording media at extremely high areal density.展开更多
We examine the space-time structure of particle-emitting source and two-pion interferometry in a smoothed hydrodynamic model with fluctuating initial conditions. An equation of state with a crossover transition betwee...We examine the space-time structure of particle-emitting source and two-pion interferometry in a smoothed hydrodynamic model with fluctuating initial conditions. An equation of state with a crossover transition between quark-gluon plasma and hadronic gas is adopted in the description of the system evolution. We find that the fluctuating initial conditions lead to inhomogeneous particle-emitting sources. The interferometry results of Rs and Ro indicate that both the source size and the duration of pion emission decrease when the freeze-out temperature increases. The values of Ro/Rs obtained by our simulated two-pion interferometry are consistent with the previous results of smoothed particle hydrodynamics, and smaller than those calculated in usual hydrodynamic models.展开更多
目的利用大语言模型(Large Language Model,LLM)进行电子病历文本结构化,验证LLM在文本结构化方面的优越性。方法采用百度的文心一言,依据优化后的提示语,通过Python调用LLM应用程序编程接口的方式进行电子病历文本结构化,从而得到结构...目的利用大语言模型(Large Language Model,LLM)进行电子病历文本结构化,验证LLM在文本结构化方面的优越性。方法采用百度的文心一言,依据优化后的提示语,通过Python调用LLM应用程序编程接口的方式进行电子病历文本结构化,从而得到结构化特征。将提取无误的特征数与提取出的所有特征数之比定为提取准确度,用以评价LLM进行文本结构化的性能。结果对100份脑卒中患者的电子病历进行文本结构化,按病历统计,平均电子病历文本的每份提取准确度为98.7%,精准度为97.5%,召回率为98.9%;按特征词统计,所有特征词的平均提取准确度、精准度和召回率分别为98.7%、96.4%和98.6%;按特征大类统计,症状、既往史、用药和诊断结果的提取准确度分别为99.3%、98.0%、98.8%和100%。结论利用LLM进行电子病历文本结构化具有可行性,百度的文心一言在电子病历文本结构化中具有优越性。展开更多
文摘In fundamental theories of physics, the dynamical equations all have time inversion invariance. Except for the evolution of some simple system which has realistic inverse processes, but for a slightly more complicated system, the evolution processes are irreversible. This is the problem of arrow of time, which is always warmly debated. In different point of view, we find there may have some conceptual misunderstanding in the controversy: 1) The realization of an inverse process does not mean the time of the system goes backward. 2) The principles of relativity and covariance are the constraints to physical laws, but not constraints to specific solutions. The equations must be covariant, but the solutions are not definitely symmetric. 3) Time is a global property of the universe, which is a measurement of the evolution process of the universe. The internal time of a matter system reflecting its internal evolution speed also takes this cosmic time as a unified background and standard of measurement. 4) The universe has a unified cosmic time T and a cosmic space related to this cosmic time. They are objective and absolute. 5) The eigensolution of a spinor is a critical state losing time concept, which responses the interaction of environment with some uncertainty, then the evolution process of the world is not uniquely determined. 6) The non-uniqueness of the evolution process means that the inverse process is absent. So for a world including spinors, the evolution is essentially irreversible. In this paper, according to the widely accepted principles and direct calculations of transformation, we reveal the misunderstandings in the usual controversy, and then give more natural and reasonable explanations for structure of space-time and arrow of time.
文摘When we study Lorentz transformation in the framework of quantum gauge theory of gravity, we will find that the vacuum gravitational gauge field will be changed under gravitational gauge transformation, which will change the structure of the physical space-time and cause clock dilation effect. The study in this paper provides us with new insights to understand the essential and intrinsic relation between special relativity and general relativity. It provides us with a new way to unify special relativity and general relativity.
基金Project(10274018) supported by the National Natural Science Foundation of China project(Z200102) supported the KeyFoundation of Hebei Normal University project(2002116) supported the Foundation Education Department of of Hebei Provin
文摘FePt granular films were prepared by direct current facing-target magnetron sputtering system onto glass substrates and subsequently in-situ annealed in vacuum. Vibrating sample magnetometer, X-ray diffraction and scanning probe microscope were applied to study the magnetic properties, microstructures, morphologies and domain structures of the samples. （FePt）27Ti73 bilayer films were fabricated at various conditions to investigate the effect of Ti on FePt grains. The results show that without Ti matrix layer, FePt films deposited onto the glass substrates are fcc disordered; with addition of Ti matrix layer, FePt/Ti films form a ternary （FePt）27Ti73 alloy possessing fcc and L10 （111） mixed texture. FePt/（FePt）27Ti73 films with perfectly ordered L10（111） structure and unique magnetic properties can be obtained at Ti thickness of 35nm and substrate temperature of 250℃. The maximum coercivity is more than 240kA/m and the squareness ratio is more than 0.9. The obtained results suggest that the granular FePt/（FePt）27Ti73 films can be applicable to ultrahigh-density magnetic recording media.
基金the Special Project of the Shanghai Municipal Commission of Economy and Information Technology for Promoting High-Quality Industrial Development(No.2024-GZL-RGZN-02011)the Shanghai City Digital Transformation Project(No.202301002)the Project of Shanghai Shenkang Hospital Development Center(No.SHDC22023214)。
文摘Surgical site infections(SSIs)are the most common healthcare-related infections in patients with lung cancer.Constructing a lung cancer SSI risk prediction model requires the extraction of relevant risk factors from lung cancer case texts,which involves two types of text structuring tasks:attribute discrimination and attribute extraction.This article proposes a joint model,Multi-BGLC,around these two types of tasks,using bidirectional encoder representations from transformers(BERT)as the encoder and fine-tuning the decoder composed of graph convolutional neural network(GCNN)+long short-term memory(LSTM)+conditional random field(CRF)based on cancer case data.The GCNN is used for attribute discrimination,whereas the LSTM and CRF are used for attribute extraction.The experiment verified the effectiveness and accuracy of the model compared with other baseline models.
文摘In this paper, a new observation equation of non-Gaussian frequency selective fading Bell Labs layered space time （BLAST） architecture system is proposed, which is used for frequency selective fading channels and non-Gaussian noise in an application environment of BLAST system. With othogonal matrix triangularization （QR decomposition） of the channel matrix, the static observation equation of frequency selective fading BLAST system is transformed into a dynamic state space model, and then the particle filter is used for space-time layered detection. Making the full use of the finite alphabet of the digital modulation communication signal, the optimal proposal distribution can be chosen to produce particle and update the weight. Incorporated with current method of reducing error propagation, a new space-time layered detection algorithm is proposed. Simulation result shows the validity of the proposed algorithm.
文摘Shallow surface wave methods are mostly used for investigation of the surface velocity structure in environmental and engineering geophysics in non-desert areas. For the special geological features of the Takelamagan Desert area, we use the multi-channel analysis of surface wave （MASW） method to process multi-channel shallow surface wave records to determine the near surface velocity structure in the desert area. We also process, analyze, and compare the surface waves in many-trace records extracted from the oil exploration shot gathers in the area. We show that the MASW method can determine detailed shallow velocity structure in desert areas and the many-trace records can be used to get detailed deep geological structure. The combination of the two different datasets can obtain the exact velocity structure upper 60 m depth in the survey area.
基金This work was financially supported by the National Natural Science Foundation of China (No.10274018) and the Foundation of Hebei Provincial Education Department (No.2002116).
文摘TiCoTi granular films were prepared by DC facing-target magnetron sputtering system onto glass substrates and subsequently in situ annealing in vacuum. Structural of Ti (t nm)/Co (40 nm)/Ti (t nm) films were investigated in detail, which shows that the majority Co nanograins are formed as the hexagonal-close-packed (HCP) structure. Vibrating sample magnetometer (VSM) and scanning probe microscope (SPM) were applied to study the magnetic properties, morphologies and domain structures of these samples. It has been found that the structure and magnetic properties of the Ti/Co/Ti films depend strongly on the Ti layer thickness. The out-of-plane coercivities (Hc) of the film is maximum about 78.8 kA·m-1 when t=5 nm with annealing at 300 ℃; the distributing of grains of the sample is uniformity; and the average size of particles is about 13 nm. The obtained results suggest that this system is perpendicular anisotropy and might be applicable to perpendicular magnetic recording media.
基金Supported by the Ministry of Finance of the People’s Republic of China from 2022 to 2024(grant number 102393220020070000016).
文摘Introduction:Traditional dietary surveys are timeconsuming,and manual recording may lead to omissions.Improvement during data collection is essential to enhance accuracy of nutritional surveys.In recent years,large language models(LLMs)have been rapidly developed,which can provide text-processing functions and assist investigators in conducting dietary surveys.Methods:Thirty-eight participants from 15 families in the Huangpu and Jiading districts of Shanghai were selected.A standardized 24-hour dietary recall protocol was conducted using an intelligent recording pen that simultaneously captured audio data.These recordings were then transcribed into text.After preprocessing,we used GLM-4 for prompt engineering and chain-of-thought for collaborative reasoning,output structured data,and analyzed its integrity and consistency.Model performance was evaluated using precision and F1 scores.Results:The overall integrity rate of the LLMbased structured data reached 92.5%,and the overall consistency rate compared with manual recording was 86%.The LLM can accurately and completely recognize the names of ingredients and dining and production locations during the transcription.The LLM achieved 94%precision and an F1 score of 89.7%for the full dataset.Conclusion:LLM-based text recognition and structured data extraction can serve as effective auxiliary tools to improve efficiency and accuracy in traditional dietary surveys.With the rapid advancement of artificial intelligence,more accurate and efficient auxiliary tools can be developed for more precise and efficient data collection in nutrition research.
基金supported by the Shanghai Central Guidance Science and Technology Development Fund[YDZX20233100004008].
文摘This paper focuses on the design of an impact-resistant protective structure for an ejection flight data recording and emergency tracking system.To ensure that the protective structure possesses excellent impact resistance and energy absorption performance under the design constraints of light weight and miniaturization,a preliminary design of the impact-resistant protective structure is achieved by adopting a thin-walled shell with a periodic perforation pattern based on the analysis of protective theory and design principles.A parametric study of the structure through axial compression simulations indicate that the structure exhibits superior energy absorption when subjected to lower impact velocities,larger wall thicknesses,and moderate hole diameters.A multi-objective optimization for structural dimensions is conducted to maximize specific energy absorption and minimize peak crushing force.The performance of the impact-resistant structure is validated with a numerical model by analyzing the stress distribution and acceleration of the circuit board.The results show that the optimized structure reduces the peak stress by 15%and the maximum acceleration by 44%.
基金This work was financially supported by the National Science Fund for Distinguished Young Scholars and the National Natural Science Foundation of China (No. 50325209, 50232030).
文摘Fe100-xPtx(x=30at.%-60at.%) nanocomposite films were deposited on natural-oxidized Si(100) substrates by magnetron sputtering. The as-deposited films were annealed between 373 and 1073 K. In situ X-ray diffraction shows that the FePt nanocomposite films undergo a phase transformation from a disordered FCC phase to an ordered L10 phase between 673 and 773 K. The coercivity is 306 kA·m-1 whiles the average grain sizes is about 10 nm in the optimized FePt alloy film sample annealed at 673 K. The adjustable coercivity and fine grain size suggest that this FePt nanocomposites system is suitable as recording media at extremely high areal density.
基金Supported by National Natural Science Foundation of China (10775024)Foundation of Theoretical Nuclear Physics Center of National Laboratory of Heavy Ion Accelerator of Lanzhou
文摘We examine the space-time structure of particle-emitting source and two-pion interferometry in a smoothed hydrodynamic model with fluctuating initial conditions. An equation of state with a crossover transition between quark-gluon plasma and hadronic gas is adopted in the description of the system evolution. We find that the fluctuating initial conditions lead to inhomogeneous particle-emitting sources. The interferometry results of Rs and Ro indicate that both the source size and the duration of pion emission decrease when the freeze-out temperature increases. The values of Ro/Rs obtained by our simulated two-pion interferometry are consistent with the previous results of smoothed particle hydrodynamics, and smaller than those calculated in usual hydrodynamic models.
文摘采用手工阅读分析肺结节病历的方式容易产生实体遗漏和提取特征效率低下问题。为方便医生做肺结节病历的研究,基于ERNIE 2.0模型,对肺结节病历中有医学研究价值的疾病、异常检测结果、直径等实体进行抽取,处理成结构化文本,便于医生进行相关检索、统计与研究。实验结果表明,该模型具有深度剖析知识增强语义能力,具有更丰富的语料库,相较于固定规则,可以理解相对复杂的语义,有一定的泛化性,效果提升显著,F1值可达94%,优于BiLSTM(Bidirectional Long-Short Term Memory)和BERT模型的结果。
文摘目的利用大语言模型(Large Language Model,LLM)进行电子病历文本结构化,验证LLM在文本结构化方面的优越性。方法采用百度的文心一言,依据优化后的提示语,通过Python调用LLM应用程序编程接口的方式进行电子病历文本结构化,从而得到结构化特征。将提取无误的特征数与提取出的所有特征数之比定为提取准确度,用以评价LLM进行文本结构化的性能。结果对100份脑卒中患者的电子病历进行文本结构化,按病历统计,平均电子病历文本的每份提取准确度为98.7%,精准度为97.5%,召回率为98.9%;按特征词统计,所有特征词的平均提取准确度、精准度和召回率分别为98.7%、96.4%和98.6%;按特征大类统计,症状、既往史、用药和诊断结果的提取准确度分别为99.3%、98.0%、98.8%和100%。结论利用LLM进行电子病历文本结构化具有可行性,百度的文心一言在电子病历文本结构化中具有优越性。
