In this paper, a photoelectric signal obtained scheme via equator triangle pattern engraved on rotor is discussed and the mathematic model is deduced in the case which is deflexion between rotor axis and the coordinat...In this paper, a photoelectric signal obtained scheme via equator triangle pattern engraved on rotor is discussed and the mathematic model is deduced in the case which is deflexion between rotor axis and the coordinate frame of case. The deflexion error and coupling error under the situation are analyzed. Finally, three methods of engraving based on the spherical triangle pattern are presented. The error models of various methods are built up and the simulation curves are provided respectively. We have done the primary experiments on the surface of rotor using this method. It can be seen from the enlarged figures that the rim of the pattern is smooth and the demand of sensor resolution is satisfied by and large. The results of study supply reference for signal obtaining.展开更多
Herman Melville(1819-1891) is one of the famous writers in the history of American and world literature. Moby Dick is one of the masterpieces of Melville, and it is also his most famous ocean works in his late life. M...Herman Melville(1819-1891) is one of the famous writers in the history of American and world literature. Moby Dick is one of the masterpieces of Melville, and it is also his most famous ocean works in his late life. Moby Dick describes a story on Captain Ahab took revenge on white whale. This paper will discuss Captain Ahab's paranoid personality, and reveal how Melville reflected in the works: coexistence between human and nature. A brief description will be provided for the writer's life and his works, and then I will discuss Captain Ahab's paranoid personality through his whaling capturing process. Then, I will discuss obtaining principles of Captain Ahab, Mate Starbuck, Crew Ishmael, and reveal the Captain's tragic causes and reflected thinking. Finally, I will make a conclusion only if people adopt right obtaining principles to natural resources, could we live with nature altogether.展开更多
In the strap-down TV guidance system, the line-of-sight（LOS） rate can not be obtained frora the measured information, the math platform to select missile attitude information must be set up. The LOS rate selecting m...In the strap-down TV guidance system, the line-of-sight（LOS） rate can not be obtained frora the measured information, the math platform to select missile attitude information must be set up. The LOS rate selecting models based on the missile attitude angle and the rate gyro are set up, the influencing factor and the extracting precision of LOS rate are emulated and analyzed.展开更多
Utilization of the shift operator to represent Euler polynomials as polynomials of Appell type leads directly to its algebraic properties, its relations with powers sums;may be all its relations with Bernoulli polynom...Utilization of the shift operator to represent Euler polynomials as polynomials of Appell type leads directly to its algebraic properties, its relations with powers sums;may be all its relations with Bernoulli polynomials, Bernoulli numbers;its recurrence formulae and a very simple formula for calculating simultaneously Euler numbers and Euler polynomials. The expansions of Euler polynomials into Fourier series are also obtained;the formulae for obtaining all π<sup>m</sup> as series on k<sup>-m</sup> and for expanding functions into series of Euler polynomials.展开更多
“Obtaining” verbs depict a person taking temporary possession of an object. They signal an event of the transferring of one thing from its original owner to a potential possessor. Based on theories of Cognitive Sema...“Obtaining” verbs depict a person taking temporary possession of an object. They signal an event of the transferring of one thing from its original owner to a potential possessor. Based on theories of Cognitive Semantics, this paper intends to probe into the semantic features of English “obtaining” verbs and the different profiles, background frames entailed in different words, hoping to shed light on the further study of the syntactic performance of this category of verbs.展开更多
Objective This study aimed to explore the mechanism of obtaining yang from yin in Yougui pill against aging based on network pharmacology and molecular docking technology.Methods The active components and targets of Y...Objective This study aimed to explore the mechanism of obtaining yang from yin in Yougui pill against aging based on network pharmacology and molecular docking technology.Methods The active components and targets of Yougui Pill were obtained by searching the Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform(TCMSP)database and the Bioinformatics Analysis Tool for Molecular mechANism of Traditional Chinese Medicine(BATMEN-TCM)database,and kidney deficiency syndrome-related targets were obtained in the Symptom Mapping(SymMap)Database,a traditional Chinese medicine(TCM)syndrome correlation database.The protein–protein interaction(PPI)network was constructed by using the STRING11.5 database.Then,we used CytoScape3.9.0 software to construct the network of TCM–active components–potential targets,and the core TCM components and core targets of Yougui Pill for the treatment of kidney deficiency were obtained.The function analysis of Gene Ontology(GO)and Kyoto Encyclopedia of Genes and Genomes(KEGG)signaling pathway enrichment analysis were performed in the Database for Annotation,Visualization,and Integrated Discovery(DAVID).Finally,preliminary verification was performed with the help of molecular docking technology.Results A total of 147 active components of 9 drugs of Yougui Pill(Fuzi[Aconiti Lateralis Radix Praeparata],Shudihaung[Rehmanniae Radix Praeparata],Gouqi[Lycii Fructus],Shanyao[Rhizoma Dioscoreae],Shanzhuyu[Corni Fructus],Tusizi[Cuscutae Semen],Danggui[Angelicae Sinensis Radix],Duzhong[Eucommiae Cortex],Lujiaojiao[Cervi Cornus Colla])were obtained,corresponding to 233 targets.A total of 2,235targets related to kidney deficiency syndrome and 43 potential therapeutic targets were obtained after the intersection.The core TCM components mainly included quercetin,kaempferol,diosgenin,β-carotene,etc.The core targets involved Trp53(Tp53),Akt1,Pparg,Nr3c1,App,Casp8,Mapk1,Cav1,and Ctnnb1.A total of 27biological processes,10 cellular components,and 11 molecular functions were obtained by gene function enrichment analysis,mainly related to the regulation of gene expression,cell apoptosis and proliferation,and the response to estrogen.A total of 51 KEGG signaling pathways,mainly involving a variety of cancer pathways,apoptosis pathways,longevity regulation pathways,etc.Conclusion Yougui Pill can play a role in preventing and treating kidney deficiency syndrome through multiple targets and pathways.展开更多
The quest for sustainable energy solutions has intensified the search for alternative feedstocks that can supplement or replace fossil fuels. Obtaining fuels or chemicals through the conversion of renewable biomass is...The quest for sustainable energy solutions has intensified the search for alternative feedstocks that can supplement or replace fossil fuels. Obtaining fuels or chemicals through the conversion of renewable biomass is a promising candidate [1,2]. Some noblemetal-based (e.g., Pt, Pd and Rh) catalysts exhibit significant catalytic activity to the conversion reaction of these biomass.展开更多
The degree of polarization (DOP) ellipsoid can be used as either feedback or feedforward signal for automatic polarization mode dispersion compensation. We have realized the experiment for obtaining DOP ellipsoid from...The degree of polarization (DOP) ellipsoid can be used as either feedback or feedforward signal for automatic polarization mode dispersion compensation. We have realized the experiment for obtaining DOP ellipsoid from 100 sampling data of output states of polarization using particle swarm optimization (PSO) as ellipsoid data fitting algorithm. It was shown that the PSO algorithm was powerful for ellipsoid data fitting with high precision within 250 ms.展开更多
In this letter, a thin slab of glass is used as Fabry-Perot etalon inside a cavity of a continuous wave （CW） Nd：YAG laser to change the behavior of its output longitudinal modes. The slab etalon is used as tuning e...In this letter, a thin slab of glass is used as Fabry-Perot etalon inside a cavity of a continuous wave （CW） Nd：YAG laser to change the behavior of its output longitudinal modes. The slab etalon is used as tuning element when it turns around the laser cavity axis. Two simultaneous longitudinal modes with a relatively wide tuning range from 5.83 MHz to 0,02 THz are obtained when the Nd：YAG laser is operated at moderate output power of about 120 roW. The mode structure of this configuration is modeled and simulated. Computer-generated diagrams are also presented schematically and compared with the experimental results.展开更多
Stem cells play a crucial role in maintaining tissue regenerative capacity and homeostasis.However,mechanisms associated with stem cell senescence require further investigation.In this study,we conducted a proteomic a...Stem cells play a crucial role in maintaining tissue regenerative capacity and homeostasis.However,mechanisms associated with stem cell senescence require further investigation.In this study,we conducted a proteomic analysis of human dental pulp stem cells(HDPSCs)obtained from individuals of various ages.Our findings showed that the expression of NUP62 was decreased in aged HDPSCs.We discovered that NUP62 alleviated senescence-associated phenotypes and enhanced differentiation potential both in vitro and in vivo.Conversely,the knocking down of NUP62 expression aggravated the senescence-associated phenotypes and impaired the proliferation and migration capacity of HDPSCs.Through RNA-sequence and decoding the epigenomic landscapes remodeled induced by NUP62 overexpression,we found that NUP62 helps alleviate senescence in HDPSCs by enhancing the nuclear transport of the transcription factor E2F1.This,in turn,stimulates the transcription of the epigenetic enzyme NSD2.Finally,the overexpression of NUP62 influences the H3K36me2 and H3K36me3 modifications of anti-aging genes(HMGA1,HMGA2,and SIRT6).Our results demonstrated that NUP62 regulates the fate of HDPSCs via NSD2-dependent epigenetic reprogramming.展开更多
Aiming at the problems of low detection efficiency and difficult positioning of traditional steel surface defect detection methods,a lightweight steel surface defect detection model based on you only look once version...Aiming at the problems of low detection efficiency and difficult positioning of traditional steel surface defect detection methods,a lightweight steel surface defect detection model based on you only look once version 7(YOLOv7)is proposed.First,a cascading style sheets(CSS)block module is proposed,which uses more lightweight operations to obtain redundant information in the feature map,reduces the amount of computation,and effectively improves the detection speed.Secondly,the improved spatial pyramid pooling with cross stage partial convolutions(SPPCSPC)structure is adopted to ensure that the model can also pay attention to the defect location information while predicting the defect category information,obtain richer defect features.In addition,the convolution operation in the original model is simplified,which significantly reduces the size of the model and helps to improve the detection speed.Finally,using efficient intersection over union(EIOU)loss to focus on high-quality anchors,speed up convergence and improve positioning accuracy.Experiments were carried out on the Northeastern University-defect(NEU-DET)steel surface defect dataset.Compared with the original YOLOv7 model,the number of parameters of this model was reduced by 40%,the frames per second(FPS)reached 112,and the average accuracy reached 79.1%,the detection accuracy and speed have been improved,which can meet the needs of steel surface defect detection.展开更多
In this article the deficiency of "production function method" widely usedin present appraisal of land value in our country is analysed, and the application of theoret-ical method of deriving urban datum lan...In this article the deficiency of "production function method" widely usedin present appraisal of land value in our country is analysed, and the application of theoret-ical method of deriving urban datum land value by "Rent-Profit Ratio Method", whichmight be used for reference in the fields of land administration performed by city govern-ments, the programmes of urban planning formulated by planning departments and fur-ther performing the study of land economics, is proposed.展开更多
This report describes a new method, the self-searching method, to find cigenrays in an ocean where there is a three-dimensional sound speed perturbation blob on a uniform sound speed background. Compared with the trad...This report describes a new method, the self-searching method, to find cigenrays in an ocean where there is a three-dimensional sound speed perturbation blob on a uniform sound speed background. Compared with the traditional shooting method, this method can reduce the number of ray calculations by about two orders of magnitude, and an eigcnray can be found by computer program without manual intervention.展开更多
A method for the inversion of the transmission losses for the bottom reflection loss is proposed on the basis of the theory of the smooth- averaged sound field. The procedure of the inversion is based on the criterion...A method for the inversion of the transmission losses for the bottom reflection loss is proposed on the basis of the theory of the smooth- averaged sound field. The procedure of the inversion is based on the criterion of the least square error in the transmission losses between calculation and measurement. By using the Gauss - Newton iterative approach, the non - linear least square aloqrithm is equivalent to solving a sequence of lineared least square problems. The physical causes of the instability of the inversion problem are discussed and the stability is improved by means of the Levenberg- Marquardt method. Both numerical simulations with noise and experimental results show that the inversion for the bottom reflection loss of small grazing angle has high precision and the certain perturbation in the measured transmission losses does not lead to serious deviation in the inversion result of the bottom reflection loss.展开更多
Short-duration heavy rainfall(SHR),as delineated by the National Meteorological Center of the China Me-teorological Administration,is characterized by hourly rainfall amounts no less than 20.0 mm.SHR is one of the mos...Short-duration heavy rainfall(SHR),as delineated by the National Meteorological Center of the China Me-teorological Administration,is characterized by hourly rainfall amounts no less than 20.0 mm.SHR is one of the most common convective weather phenomena that can cause severe damage.Short-range forecasting of SHR is an important part of operational severe weather prediction.In the present study,an improved objective SHR forecasting scheme was developed by adopting the ingredients-based methodology and using the fuzzy logic approach.The 1.0°×1.0°National Centers for Environmental Prediction(NCEP)final analysis data and the ordinary rainfall(0.1-19.9 mm h-1)and SHR observational data from 411 stations were used in the improved scheme.The best lifted index,the total precipitable water,the 925 hPa specific humidity(Q 925),and the 925 hPa divergence(DIV 925)were selected as predictors based on objective analysis.Continuously distributed membership functions of predictors were obtained based on relative frequency analysis.The weights of predictors were also objectively determined.Experiments with a typhoon SHR case and a spring SHR case show that the main possible areas could be captured by the improved scheme.Verification of SHR forecasts within 96 hours with NCEP global forecasts 1.0°×1.0°data initiated at 08:00 Beijing Time during the warm seasons in 2015 show the results were improved from both deterministic and probabilistic perspectives.This study provides an objectively feasible choice for short-range guidance forecasts of SHR.The scheme can be applied to other convective phenomena.展开更多
This essay studies the phenomenon of‘obtaining of qi’in acupuncture.Combined with clinical practice,the authors think that it was a habitual misunderstanding in the past to equate‘needling sensation’to ‘obtaining...This essay studies the phenomenon of‘obtaining of qi’in acupuncture.Combined with clinical practice,the authors think that it was a habitual misunderstanding in the past to equate‘needling sensation’to ‘obtaining of qi’in acupuncture practice.The two concepts are different and are related with each other.The authors have also classified the phenomenon of‘obtaining of qi’according to its depth in the skin layer. Based on the research achievements in neuroscience,the authors propose the study on‘catching’the specific cerebrations,so as to reveal the essence of‘obtaining of qi’.展开更多
From the hypotheses that the position-representation of a physical state is the Fourier transform of its momentum-representation and that the timerepresentation is the inverse Fourier transform of its energy-represent...From the hypotheses that the position-representation of a physical state is the Fourier transform of its momentum-representation and that the timerepresentation is the inverse Fourier transform of its energy-representation, we are able to obtain the Planck relation E = hν , the de Broglie relation p = h /λ , the Dirac fundamental commutation relation, the Schr?dinger equations, the Heisenberg uncertainty principle in quantum mechanics, and the annihilation/creation of a photon from excitation/de-excitation of an atom following Bohr.展开更多
文摘In this paper, a photoelectric signal obtained scheme via equator triangle pattern engraved on rotor is discussed and the mathematic model is deduced in the case which is deflexion between rotor axis and the coordinate frame of case. The deflexion error and coupling error under the situation are analyzed. Finally, three methods of engraving based on the spherical triangle pattern are presented. The error models of various methods are built up and the simulation curves are provided respectively. We have done the primary experiments on the surface of rotor using this method. It can be seen from the enlarged figures that the rim of the pattern is smooth and the demand of sensor resolution is satisfied by and large. The results of study supply reference for signal obtaining.
文摘Herman Melville(1819-1891) is one of the famous writers in the history of American and world literature. Moby Dick is one of the masterpieces of Melville, and it is also his most famous ocean works in his late life. Moby Dick describes a story on Captain Ahab took revenge on white whale. This paper will discuss Captain Ahab's paranoid personality, and reveal how Melville reflected in the works: coexistence between human and nature. A brief description will be provided for the writer's life and his works, and then I will discuss Captain Ahab's paranoid personality through his whaling capturing process. Then, I will discuss obtaining principles of Captain Ahab, Mate Starbuck, Crew Ishmael, and reveal the Captain's tragic causes and reflected thinking. Finally, I will make a conclusion only if people adopt right obtaining principles to natural resources, could we live with nature altogether.
文摘In the strap-down TV guidance system, the line-of-sight（LOS） rate can not be obtained frora the measured information, the math platform to select missile attitude information must be set up. The LOS rate selecting models based on the missile attitude angle and the rate gyro are set up, the influencing factor and the extracting precision of LOS rate are emulated and analyzed.
文摘Utilization of the shift operator to represent Euler polynomials as polynomials of Appell type leads directly to its algebraic properties, its relations with powers sums;may be all its relations with Bernoulli polynomials, Bernoulli numbers;its recurrence formulae and a very simple formula for calculating simultaneously Euler numbers and Euler polynomials. The expansions of Euler polynomials into Fourier series are also obtained;the formulae for obtaining all π<sup>m</sup> as series on k<sup>-m</sup> and for expanding functions into series of Euler polynomials.
文摘“Obtaining” verbs depict a person taking temporary possession of an object. They signal an event of the transferring of one thing from its original owner to a potential possessor. Based on theories of Cognitive Semantics, this paper intends to probe into the semantic features of English “obtaining” verbs and the different profiles, background frames entailed in different words, hoping to shed light on the further study of the syntactic performance of this category of verbs.
基金Jiangxi University of Traditional Chinese Medicine Schoollevel Postgraduate Innovation Special Funds for Funding Projects(School Word[2023]No.33)Jiangxi Province Traditional Chinese Medicine Young and Middle-aged Backbone Talent Training Program(Third Batch)Project(Gan Traditional Chinese Medicine Science and Education[2021]No.4)。
文摘Objective This study aimed to explore the mechanism of obtaining yang from yin in Yougui pill against aging based on network pharmacology and molecular docking technology.Methods The active components and targets of Yougui Pill were obtained by searching the Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform(TCMSP)database and the Bioinformatics Analysis Tool for Molecular mechANism of Traditional Chinese Medicine(BATMEN-TCM)database,and kidney deficiency syndrome-related targets were obtained in the Symptom Mapping(SymMap)Database,a traditional Chinese medicine(TCM)syndrome correlation database.The protein–protein interaction(PPI)network was constructed by using the STRING11.5 database.Then,we used CytoScape3.9.0 software to construct the network of TCM–active components–potential targets,and the core TCM components and core targets of Yougui Pill for the treatment of kidney deficiency were obtained.The function analysis of Gene Ontology(GO)and Kyoto Encyclopedia of Genes and Genomes(KEGG)signaling pathway enrichment analysis were performed in the Database for Annotation,Visualization,and Integrated Discovery(DAVID).Finally,preliminary verification was performed with the help of molecular docking technology.Results A total of 147 active components of 9 drugs of Yougui Pill(Fuzi[Aconiti Lateralis Radix Praeparata],Shudihaung[Rehmanniae Radix Praeparata],Gouqi[Lycii Fructus],Shanyao[Rhizoma Dioscoreae],Shanzhuyu[Corni Fructus],Tusizi[Cuscutae Semen],Danggui[Angelicae Sinensis Radix],Duzhong[Eucommiae Cortex],Lujiaojiao[Cervi Cornus Colla])were obtained,corresponding to 233 targets.A total of 2,235targets related to kidney deficiency syndrome and 43 potential therapeutic targets were obtained after the intersection.The core TCM components mainly included quercetin,kaempferol,diosgenin,β-carotene,etc.The core targets involved Trp53(Tp53),Akt1,Pparg,Nr3c1,App,Casp8,Mapk1,Cav1,and Ctnnb1.A total of 27biological processes,10 cellular components,and 11 molecular functions were obtained by gene function enrichment analysis,mainly related to the regulation of gene expression,cell apoptosis and proliferation,and the response to estrogen.A total of 51 KEGG signaling pathways,mainly involving a variety of cancer pathways,apoptosis pathways,longevity regulation pathways,etc.Conclusion Yougui Pill can play a role in preventing and treating kidney deficiency syndrome through multiple targets and pathways.
文摘The quest for sustainable energy solutions has intensified the search for alternative feedstocks that can supplement or replace fossil fuels. Obtaining fuels or chemicals through the conversion of renewable biomass is a promising candidate [1,2]. Some noblemetal-based (e.g., Pt, Pd and Rh) catalysts exhibit significant catalytic activity to the conversion reaction of these biomass.
基金This work was supported by the National Natural Science Foundation of China (No. 60072042 and 60377026), the National "863" High Technology Project of China (No. 2001AA122041 and 2003AA311070), and Corporative Building Project of Beijing Educational Committee (No. XK100130437).
文摘The degree of polarization (DOP) ellipsoid can be used as either feedback or feedforward signal for automatic polarization mode dispersion compensation. We have realized the experiment for obtaining DOP ellipsoid from 100 sampling data of output states of polarization using particle swarm optimization (PSO) as ellipsoid data fitting algorithm. It was shown that the PSO algorithm was powerful for ellipsoid data fitting with high precision within 250 ms.
文摘In this letter, a thin slab of glass is used as Fabry-Perot etalon inside a cavity of a continuous wave （CW） Nd：YAG laser to change the behavior of its output longitudinal modes. The slab etalon is used as tuning element when it turns around the laser cavity axis. Two simultaneous longitudinal modes with a relatively wide tuning range from 5.83 MHz to 0,02 THz are obtained when the Nd：YAG laser is operated at moderate output power of about 120 roW. The mode structure of this configuration is modeled and simulated. Computer-generated diagrams are also presented schematically and compared with the experimental results.
基金supported by the National Natural Science Foundation of China(32171347)the Foundation of Leading Talents from Shanghai Health Commission(2022XD038)+1 种基金Training Program for Research Physicians in Innovation,the Funda-mental Research Funds for the Central Universities(YG2023QNA23)Transforma-tion from shanghai hospital development center(SHDC2022CRD002).
文摘Stem cells play a crucial role in maintaining tissue regenerative capacity and homeostasis.However,mechanisms associated with stem cell senescence require further investigation.In this study,we conducted a proteomic analysis of human dental pulp stem cells(HDPSCs)obtained from individuals of various ages.Our findings showed that the expression of NUP62 was decreased in aged HDPSCs.We discovered that NUP62 alleviated senescence-associated phenotypes and enhanced differentiation potential both in vitro and in vivo.Conversely,the knocking down of NUP62 expression aggravated the senescence-associated phenotypes and impaired the proliferation and migration capacity of HDPSCs.Through RNA-sequence and decoding the epigenomic landscapes remodeled induced by NUP62 overexpression,we found that NUP62 helps alleviate senescence in HDPSCs by enhancing the nuclear transport of the transcription factor E2F1.This,in turn,stimulates the transcription of the epigenetic enzyme NSD2.Finally,the overexpression of NUP62 influences the H3K36me2 and H3K36me3 modifications of anti-aging genes(HMGA1,HMGA2,and SIRT6).Our results demonstrated that NUP62 regulates the fate of HDPSCs via NSD2-dependent epigenetic reprogramming.
基金supported by the National Natural Science Foundation of China(No.62103298)the Natural Science Foundation of Hebei Province(No.F2018209289)。
文摘Aiming at the problems of low detection efficiency and difficult positioning of traditional steel surface defect detection methods,a lightweight steel surface defect detection model based on you only look once version 7(YOLOv7)is proposed.First,a cascading style sheets(CSS)block module is proposed,which uses more lightweight operations to obtain redundant information in the feature map,reduces the amount of computation,and effectively improves the detection speed.Secondly,the improved spatial pyramid pooling with cross stage partial convolutions(SPPCSPC)structure is adopted to ensure that the model can also pay attention to the defect location information while predicting the defect category information,obtain richer defect features.In addition,the convolution operation in the original model is simplified,which significantly reduces the size of the model and helps to improve the detection speed.Finally,using efficient intersection over union(EIOU)loss to focus on high-quality anchors,speed up convergence and improve positioning accuracy.Experiments were carried out on the Northeastern University-defect(NEU-DET)steel surface defect dataset.Compared with the original YOLOv7 model,the number of parameters of this model was reduced by 40%,the frames per second(FPS)reached 112,and the average accuracy reached 79.1%,the detection accuracy and speed have been improved,which can meet the needs of steel surface defect detection.
文摘In this article the deficiency of "production function method" widely usedin present appraisal of land value in our country is analysed, and the application of theoret-ical method of deriving urban datum land value by "Rent-Profit Ratio Method", whichmight be used for reference in the fields of land administration performed by city govern-ments, the programmes of urban planning formulated by planning departments and fur-ther performing the study of land economics, is proposed.
文摘This report describes a new method, the self-searching method, to find cigenrays in an ocean where there is a three-dimensional sound speed perturbation blob on a uniform sound speed background. Compared with the traditional shooting method, this method can reduce the number of ray calculations by about two orders of magnitude, and an eigcnray can be found by computer program without manual intervention.
基金The Project Supported by National Natural Science Fundation of China
文摘A method for the inversion of the transmission losses for the bottom reflection loss is proposed on the basis of the theory of the smooth- averaged sound field. The procedure of the inversion is based on the criterion of the least square error in the transmission losses between calculation and measurement. By using the Gauss - Newton iterative approach, the non - linear least square aloqrithm is equivalent to solving a sequence of lineared least square problems. The physical causes of the instability of the inversion problem are discussed and the stability is improved by means of the Levenberg- Marquardt method. Both numerical simulations with noise and experimental results show that the inversion for the bottom reflection loss of small grazing angle has high precision and the certain perturbation in the measured transmission losses does not lead to serious deviation in the inversion result of the bottom reflection loss.
基金Key R&D Program of Xizang Autonomous Region(XZ202101ZY0004G)National Natural Science Foundation of China(U2142202)+1 种基金National Key R&D Program of China(2022YFC3004104)Key Innovation Team of China Meteor-ological Administration(CMA2022ZD07)。
文摘Short-duration heavy rainfall(SHR),as delineated by the National Meteorological Center of the China Me-teorological Administration,is characterized by hourly rainfall amounts no less than 20.0 mm.SHR is one of the most common convective weather phenomena that can cause severe damage.Short-range forecasting of SHR is an important part of operational severe weather prediction.In the present study,an improved objective SHR forecasting scheme was developed by adopting the ingredients-based methodology and using the fuzzy logic approach.The 1.0°×1.0°National Centers for Environmental Prediction(NCEP)final analysis data and the ordinary rainfall(0.1-19.9 mm h-1)and SHR observational data from 411 stations were used in the improved scheme.The best lifted index,the total precipitable water,the 925 hPa specific humidity(Q 925),and the 925 hPa divergence(DIV 925)were selected as predictors based on objective analysis.Continuously distributed membership functions of predictors were obtained based on relative frequency analysis.The weights of predictors were also objectively determined.Experiments with a typhoon SHR case and a spring SHR case show that the main possible areas could be captured by the improved scheme.Verification of SHR forecasts within 96 hours with NCEP global forecasts 1.0°×1.0°data initiated at 08:00 Beijing Time during the warm seasons in 2015 show the results were improved from both deterministic and probabilistic perspectives.This study provides an objectively feasible choice for short-range guidance forecasts of SHR.The scheme can be applied to other convective phenomena.
基金supported by a grant from National Basic Research Program of China(973 Program,No. 2006GB504505)
文摘This essay studies the phenomenon of‘obtaining of qi’in acupuncture.Combined with clinical practice,the authors think that it was a habitual misunderstanding in the past to equate‘needling sensation’to ‘obtaining of qi’in acupuncture practice.The two concepts are different and are related with each other.The authors have also classified the phenomenon of‘obtaining of qi’according to its depth in the skin layer. Based on the research achievements in neuroscience,the authors propose the study on‘catching’the specific cerebrations,so as to reveal the essence of‘obtaining of qi’.
文摘From the hypotheses that the position-representation of a physical state is the Fourier transform of its momentum-representation and that the timerepresentation is the inverse Fourier transform of its energy-representation, we are able to obtain the Planck relation E = hν , the de Broglie relation p = h /λ , the Dirac fundamental commutation relation, the Schr?dinger equations, the Heisenberg uncertainty principle in quantum mechanics, and the annihilation/creation of a photon from excitation/de-excitation of an atom following Bohr.
