The 21 cm radiation of neutral hydrogen provides crucial information for studying the early universe and its evolution.To advance this research,countries have made significant investments in constructing large lowfreq...The 21 cm radiation of neutral hydrogen provides crucial information for studying the early universe and its evolution.To advance this research,countries have made significant investments in constructing large lowfrequency radio telescope arrays,such as the Low Frequency Array and the Square Kilometre Array Phase 1 Low Frequency.These instruments are pivotal for radio astronomy research.However,challenges such as ionospheric plasma interference,ambient radio noise,and instrument-related effects have become increasingly prominent,posing major obstacles in cosmology research.To address these issues,this paper proposes an efficient signal processing method that combines wavelet transform and mathematical morphology.The method involves the following steps:Background Subtraction:Background interference in radio observation signals is eliminated.Wavelet Transform:The signal,after removing background noise,undergoes a two-dimensional discrete wavelet transform.Threshold processing is then applied to the wavelet coefficients to effectively remove interference components.Wavelet Inversion:The processed signal is reconstructed using wavelet inversion.Mathematical Morphology:The reconstructed signal is further optimized using mathematical morphology to refine the results.Experimental verification was conducted using solar observation data from the Xinjiang Observatory and the Yunnan Observatory.The results demonstrate that this method successfully removes interference signals while preserving useful signals,thus improving the accuracy of radio astronomy observations and reducing the impact of radio frequency interference.展开更多
In this work, the growth kinetics of MX （M - metal, X - C/N） nanoprecipitates in type 347H austenitic steel was systematically studied. To investigate the coarsening behavior and the growth mechanism of MX carbonitr...In this work, the growth kinetics of MX （M - metal, X - C/N） nanoprecipitates in type 347H austenitic steel was systematically studied. To investigate the coarsening behavior and the growth mechanism of MX carbonitrides during long-term aging, experiments were performed at 700, 800, 850, and 900℃ for different periods （1, 24, 70, and 100 h）. The precipitation behavior of carbonitrides in specimens subjected to various aging conditions was explored using carbon replicas and transmission electron microscopy （TEM） observations. The corresponding sizes ofMX carbonitrides were measured. The results demonstrates that MX carbonitrides precipitate in type 347H austenitic steel as Nb（C,N）. The coarsening rate constant is time-independent; however, an increase in aging temperature results in an increase in coarsening rate of Nb（C,N）. The coarsening process was analyzed according to the calculated diffusion activation energy of Nb（C,N）. When the aging temperature was 800-900℃, the mean activation energy was 294 kJ·mol -1, and the coarsening behavior was controlled primarily by the diffusion of Nb atoms.展开更多
Severe insulin resistance has been linked to some of the most globally prevalent disorders,such as diabetes mellitus,nonalcoholic fatty liver disease,polycystic ovarian syndrome,and hypertension.Hereditary severe insu...Severe insulin resistance has been linked to some of the most globally prevalent disorders,such as diabetes mellitus,nonalcoholic fatty liver disease,polycystic ovarian syndrome,and hypertension.Hereditary severe insulin resistance syndrome(H-SIRS)is a rare disorder classified into four principal categories:primary insulin receptor defects,lipodystrophies,complex syndromes,and obesity-related H-SIRS.Genes such as INSR,AKT2,TBC1D4,AGPAT2,BSCL2,CAV1,PTRF,LMNA,PPARG,PLIN1,CIDEC,LIPE,PCYT1A,MC4R,LEP,POMC,SH2B1,RECQL2,RECQL3,ALMS1,PCNT,ZMPSTE24,PIK3R1,and POLD1 have been linked to H-SIRS.Its clinical features include insulin resistance,hyperglycemia,hyperandrogenism,severe dyslipidemia,fatty liver,abnormal topography of adipose tissue,and low serum leptin and adiponectin levels.Diagnosis of H-SIRS is based on the presence of typical clinical features associated with the various H-SIRS forms and the identification of mutations in H-SIRS-linked genes by genetic testing.Diet therapy,insulin sensitization,exogenous insulin therapy,and leptin replacement therapy have widely been adopted to manage H-SIRS.The rarity of H-SIRS,its highly variable clinical presentation,refusal to be tested for genetic mutations by patients’family members who are not severely sick,unavailability of genetic testing,and testing expenses contribute to the delayed or underdiagnoses of H-SIRS.Early diagnosis facilitates early management of the condition,which results in improved glycemic control and delayed onset of diabetes and other complications related to severe insulin resistance.The use of updated genetic sequencing technologies is recommended,and long-term studies are required for genotype–phenotype differentiation and formulation of diagnostic and treatment protocols.展开更多
基金funded by the National Key Research and Development Program’s intergovernmental International Science and Technology Innovation Cooperation project,titled Remote Sensing and Radio Astronomy Observation of Space Weather in Low and Middle Latitudes(project number:2022YFE0140000)Supported by International Partnership Program of Chinese Academy of Sciences,grant No.114A11KYSB20200001。
文摘The 21 cm radiation of neutral hydrogen provides crucial information for studying the early universe and its evolution.To advance this research,countries have made significant investments in constructing large lowfrequency radio telescope arrays,such as the Low Frequency Array and the Square Kilometre Array Phase 1 Low Frequency.These instruments are pivotal for radio astronomy research.However,challenges such as ionospheric plasma interference,ambient radio noise,and instrument-related effects have become increasingly prominent,posing major obstacles in cosmology research.To address these issues,this paper proposes an efficient signal processing method that combines wavelet transform and mathematical morphology.The method involves the following steps:Background Subtraction:Background interference in radio observation signals is eliminated.Wavelet Transform:The signal,after removing background noise,undergoes a two-dimensional discrete wavelet transform.Threshold processing is then applied to the wavelet coefficients to effectively remove interference components.Wavelet Inversion:The processed signal is reconstructed using wavelet inversion.Mathematical Morphology:The reconstructed signal is further optimized using mathematical morphology to refine the results.Experimental verification was conducted using solar observation data from the Xinjiang Observatory and the Yunnan Observatory.The results demonstrate that this method successfully removes interference signals while preserving useful signals,thus improving the accuracy of radio astronomy observations and reducing the impact of radio frequency interference.
基金the China National Funds for Distinguished Young Scientists (No.51325401)the National High Technology Research and Development Program of China (No.2015AA042504)the National Natural Science Foundation of China (No.51474156) for financial support
文摘In this work, the growth kinetics of MX （M - metal, X - C/N） nanoprecipitates in type 347H austenitic steel was systematically studied. To investigate the coarsening behavior and the growth mechanism of MX carbonitrides during long-term aging, experiments were performed at 700, 800, 850, and 900℃ for different periods （1, 24, 70, and 100 h）. The precipitation behavior of carbonitrides in specimens subjected to various aging conditions was explored using carbon replicas and transmission electron microscopy （TEM） observations. The corresponding sizes ofMX carbonitrides were measured. The results demonstrates that MX carbonitrides precipitate in type 347H austenitic steel as Nb（C,N）. The coarsening rate constant is time-independent; however, an increase in aging temperature results in an increase in coarsening rate of Nb（C,N）. The coarsening process was analyzed according to the calculated diffusion activation energy of Nb（C,N）. When the aging temperature was 800-900℃, the mean activation energy was 294 kJ·mol -1, and the coarsening behavior was controlled primarily by the diffusion of Nb atoms.
基金supported by the National Natural Science Foundation of China(No.8217033609,81770880,81800788,and 81970762)the Science&Technology Department of Hunan Province(China)(No.2020SK2080,and 2015JC3012)Changsha Science&Technology(China)(No.k1906019,and kq1901118).
文摘Severe insulin resistance has been linked to some of the most globally prevalent disorders,such as diabetes mellitus,nonalcoholic fatty liver disease,polycystic ovarian syndrome,and hypertension.Hereditary severe insulin resistance syndrome(H-SIRS)is a rare disorder classified into four principal categories:primary insulin receptor defects,lipodystrophies,complex syndromes,and obesity-related H-SIRS.Genes such as INSR,AKT2,TBC1D4,AGPAT2,BSCL2,CAV1,PTRF,LMNA,PPARG,PLIN1,CIDEC,LIPE,PCYT1A,MC4R,LEP,POMC,SH2B1,RECQL2,RECQL3,ALMS1,PCNT,ZMPSTE24,PIK3R1,and POLD1 have been linked to H-SIRS.Its clinical features include insulin resistance,hyperglycemia,hyperandrogenism,severe dyslipidemia,fatty liver,abnormal topography of adipose tissue,and low serum leptin and adiponectin levels.Diagnosis of H-SIRS is based on the presence of typical clinical features associated with the various H-SIRS forms and the identification of mutations in H-SIRS-linked genes by genetic testing.Diet therapy,insulin sensitization,exogenous insulin therapy,and leptin replacement therapy have widely been adopted to manage H-SIRS.The rarity of H-SIRS,its highly variable clinical presentation,refusal to be tested for genetic mutations by patients’family members who are not severely sick,unavailability of genetic testing,and testing expenses contribute to the delayed or underdiagnoses of H-SIRS.Early diagnosis facilitates early management of the condition,which results in improved glycemic control and delayed onset of diabetes and other complications related to severe insulin resistance.The use of updated genetic sequencing technologies is recommended,and long-term studies are required for genotype–phenotype differentiation and formulation of diagnostic and treatment protocols.
