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Linear Correlations between Peak Frequency of Gyrosynchrotron Spectrum and Photosphere Magnetic Fields

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Chinese Journal of Astronomy and Astrophysics 2007年第4期7卷 487-495页

作者： ai-hua zhou Jian-Ping Li Purple Mountain Observatory Chinese Academy of Sciences Nanjing 210008

The gyrosynchrotron spectra are computed in a nonuniform magnetic field case, taking into account the self- and gyroresonance absorption. It is found that the peak frequency νp of the gyrosynchrotron spectrum systematically increases with the increasing photosphere magnetic field strength B0 and increasing viewing angle θ. It is also found for the first time that there are good positive linear correlations between νp and B0, and between log νp and log θ, with linear correlation coefficient 0.99 between νp and B0 and 0.95 between log νp and log θ. We apply the correlations to analyze two burst events observed with OVSA and find that the evolution tendencies of the photosphere magnetic field strength B0 estimated from the above expression are comparable with the observational results of SOHO/MDI. We also give a comparison of the diagnostic results of coronal magnetic field strength in both uniform and nonuniform source models.

关键词： Sun: flare - sun: radio emission - Sun: magnetic field

Study of temporal evolution of emission spectrum in a steeply rising submillimeter burst

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Research in Astronomy and Astrophysics 2016年第1期16卷 67-72页

作者： Jian-Ping Li ai-hua zhou Xin-Dong Wang Key Laboratory of Dark Matter and Space Astronomy Chinese Academy of Sciences Nanjing 210008 China Purple Mountain Observatory Chinese Academy of Sciences Nanjing 210008 China School of Public Administration Hohai University Nanjing 210098 China

The temporal evolution of a spectrum during a steeply rising submillimeter（THz） burst that occurred on 2003 November 2 was investigated in detail for the first *** show that the flux density of the THz spectrum increased steeply with frequency above 200 *** average rising rates reached a value of 235 sfu GHz^（-1）（corresponding to spectral index α of 4.8） during the *** flux densities reached about 4 000 and 70 000 sfu at 212 and 405 GHz at the maximum phase,*** emissions at 405 GHz maintained such a continuous high level that they largely exceeded the peak values of the microwave（MW） spectra during the main *** studies suggest that only energetic electrons with a low-energy cutoff of~ 1 MeV and number density of ~ 10~6-10~8 cm^（-3） can produce such a strong and steeply rising THz component via gyrosynchrotron radiation based on numerical simulations of burst spectra in the case of a nonuniform magnetic *** electron number density N,derived from our numerical fits to the THz temporal evolution spectra,increased substantially from 8 ×10~6 to 4 × 10~8 cm^（-3）,i.e.,the N value increased 50 times during the rise *** the decay phase it decreased to 7 ×10~7 cm^（-3）,i.e.,it decreased by about five times from the maximum *** total electron number decreased an order of magnitude from the maximum phase to the decay ***,the variation in amplitude of N is only about one time in the MW emission source during this burst,and the total electron number did not decrease but increased by about 20%during the decay ***,we find that the THz source radius decreased by about 24%while the MW source radius,on the contrary,increased by 28%during the decay phase.

关键词： Sun: submillimeter burst -- Sun: energetic electrons -- Sun: radio source size

Diagnostics from three rising submillimeter bursts

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Research in Astronomy and Astrophysics 2016年第2期16卷 97-104页

作者： ai-hua zhou Jian-Ping Li Xin-Dong Wang Key Laboratory of Dark Matter and Space Astronomy Chinese Academy of Sciences Purple Mountain Observatory Chinese Academy of Sciences School of Public Administration Hohai University

In this paper we investigate three novel rising submillimeter （THz） bursts that occurred sequen- tially in Super Active Region NOAA 10486. The average rising rate of the flux density above 200 GHz is only 20 sfu GHz-1 （corresponding to spectral index α of 1.6） for the THz spectral components of the 2003 October 28 and November 4 bursts, but it attained values of 235 sfu GHz-1 （α = 4.8） in the 2003 November 2 burst. The steeply rising THz spectrum can be produced by a population of highly relativistic electrons with a low-energy cutoff of 1 MeV, but it only requires a low-energy cutoff of 30 keV for the two slowly rising THz bursts, via gyrosynchrotron （GS） radiation based on our numerical simulations of burst spectra in the magnetic dipole field case. The electron density variation is much larger in the THz source than in the microwave （MW） source. It is interesting that the THz source radius decreased by 20%-50% during the decay phase for the three events, but the MW source increased by 28% for the 2003 November 2 event. In the paper we will present a formula that can be used to calculate the energy released by ultrarel- ativistic electrons, taking the relativistic correction into account for the first time. We find that the energy released by energetic electrons in the THz source exceeds that in the MW source due to the strong GS radi- ation loss in the THz range, although the modeled THz source area is 3-4 orders smaller than the modeled MW source one. The total energies released by energetic electrons via the GS radiation in radio sources are estimated, respectively, to be 5.2 × 10^33, 3.9 × 10^33 and 3.7 × 10^32 erg for the October 28, November 2 and 4 bursts, which are 131, 76 and 4 times as large as the thermal energies of 2.9 × 10^31, 2.1 × 10^31 and 5.2 × 10^31 erg estimated from soft X-ray GOES observations.

关键词： Sun submillimeter emission -- Sun energetic electrons -- Sun radio source environment

Maximum flux density of the gyrosynchrotron spectrum in a nonuniform source

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Chinese Journal of Astronomy and Astrophysics 2009年第4期9卷 475-484页

作者： ai-hua zhou Rong-Chuan Wang Cheng-Wen Shao Purple Mountain Observatory Chinese Academy of Sciences Nanjing 210008 China Graduate University of Chinese Academy of Sciences Beijing 100049 China

The maximum flux density of a gyrosynchrotron radiation spectrum in a magnetic diploe model with self absorption and gyroresonance is calculated. Our calculations show that the maximum flux density of the gyrosynchrotron spectrum increases with increasing low-energy cutoff, number density, input depth of energetic electrons, magnetic field strength and viewing angle, and with decreasing energy spectral index of energetic electrons, number density and temperature of thermal electrons. It is found that there are linear correlations between the logarithms of the maximum flux density and the above eight parameters with correlation coefficients higher than 0.91 and fit accuracies better than 10%. The maximum flux density could be a good indicator of the changes of these source parameters. In addition, we find that there are very good positive linear correlations between the logarithms of the maximum flux density and peak frequency when the above former five parameters vary respectively. Their linear correlation coefficients are higher than 0.90 and the fit accuracies are better than 0.5%.

关键词： Sun flare-Sun radio emission-Sun maximum flux

Learnware:small models do big

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Science China(Information Sciences) 2024年第1期67卷 39-50页

作者： Zhi-hua zhou Zhi-Hao TAN National Key Laboratory for Novel Software Technology Nanjing University

There are complaints about current machine learning techniques such as the requirement of a huge amount of training data and proficient training skills,the difficulty of continual learning,the risk of catastrophic forgetting,and the leaking of data privacy/*** research efforts have been focusing on one of those concerned issues separately,paying less attention to the fact that most issues are entangled in *** prevailing big model paradigm,which has achieved impressive results in natural language processing and computer vision applications,has not yet addressed those issues,whereas becoming a serious source of carbon *** article offers an overview of the learnware paradigm,which attempts to enable users not to need to build machine learning models from scratch,with the hope of reusing small models to do things even beyond their original purposes,where the key ingredient is the specification which enables a trained model to be adequately identified to reuse according to the requirement of future users who know nothing about the model in advance.

关键词： artificial intelligence machine learning learnware

Paleogene integrative stratigraphy,biotas,and paleogeographical evolution of the Qinghai-Tibetan Plateau and its surrounding areas

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Science China Earth Sciences 2024年第4期67卷 1290-1325页

作者： Jia LIU ai SONG Lin DING Tao SU Zhekun zhou CAS Key Laboratory of Tropical Forest Ecology Xishuangbanna Tropical Botanical GardenChinese Academy of SciencesMengla 666303China State Key Laboratory of Palaeobiology and Stratigraphy Nanjing Institute of Geology and PalaeontologyChinese Academy of SciencesNanjing 210008China Institute of Paleontology Yunnan UniversityKunming 650500China State Key Laboratory of Tibetan Plateau Earth System Environment and Resources(TPESER)Institute of Tibetan Plateau ResearchChinese Academy of SciencesBeijing 100101China

The Paleogene is a crucial period when terrestrial and marine ecosystems recovered from major disruptions and gradually approached their modern *** the Qinghai-Tibetan Plateau and its surrounding regions,the Paleogene also represents a significant phase of tectonic evolution in the Qinghai-Tibetan Plateau-Himalaya orogeny,reorganization of Asian climates,and evolution of *** to limitations in research conditions and understanding,there are still many controversies regarding stratigraphic divisions in the Qinghai-Tibetan Plateau and its surrounding *** recent years,extensive studies on sedimentary petrology,magnetostratigraphy,and isotope dating have been conducted in the *** fossils have been discovered and reported,contributing to a more systematic understanding of *** studies have laid a solid foundation for the comprehensive investigation of the stratigraphy,biotas and paleogeographic evolution of the Qinghai-Tibetan Plateau and its surrounding regions during the *** this paper,we integrate recent research on fossils,isotopic dating,magnetostratigraphy,and geochemistry to refine the stratigraphic divisions and correlation framework of different tectonic units in the region,building upon previous *** the Second Tibetan Plateau Scientific Expedition and Research,the knowledge of Paleogene floras has gradually *** paper discusses the biostratigraphic significance of extinct and newly appeared taxa based on the latest dating results of these plant *** new understanding of fossil species such as the“Eucalyptus”and Arecaceae establishes connections between the Paleogene flora of the Qinghai-Tibetan region and the biotas of Gondwana,specifically Oceania and South *** evolutionary history of key taxa near the Yarlung Zangbo suture zone indicates that the collision between the Indian and Eurasian plates occurred approximately 65-54 *** reconstructions,based o

关键词： Qinghai-Tibetan Plateau Fossils Biostratigraphy Paleoenvironment Paleogeography Paleogene

Cellular strategies to induce immune tolerance after liver transplantation:Clinical perspectives

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World Journal of Gastroenterology 2024年第13期30卷 1791-1800页

作者： ai-Wei zhou Jing Jin Yuan Liu Department of Liver Surgery Renji Hospital Affiliated to Shanghai Jiao Tong University School of MedicineShanghai 200127China Department of Nursing Renji Hospital Affiliated to Shanghai Jiao Tong University School of MedicineShanghai 200127China Department of Liver Transplantation Shanghai Immune Therapy InstituteShanghai 200127China

Liver transplantation(LT)has become the most efficient treatment for pediatric and adult end-stage liver disease and the survival time after transplantation is becoming longer due to the development of surgical techniques and perioperative ***,long-term side-effects of immunosuppressants,like infection,metabolic disorders and malignant tumor are gaining more *** tolerance is the status in which LT recipients no longer need to take any immunosuppressants,but the liver function and intrahepatic histology maintain *** approaches to achieve immune tolerance after transplantation include spontaneous,operational and induced *** first two means require no specific intervention but withdrawing immunosuppressant gradually during *** clinical factors or biomarkers so far could accurately predict who are suitable for immunosuppressant withdraw after *** the understanding to the underlying mechanisms of immune tolerance,many strategies have been developed to induce tolerance in LT *** strategy is one of the most promising methods for immune tolerance induction,including chimerism induced by hematopoietic stem cells and adoptive transfer of regulatory immune *** safety and efficacy of various cell products have been evaluated by prospective preclinical and clinical trials,while obstacles still exist before translating into clinical ***,we will summarize the latest perspectives and concerns on the clinical application of cellular strategies in LT recipients.

关键词： Cellular therapy Induced tolerance Liver transplantation Regulatory T cells Regulatory dendritic cells

Characterization of cerebrovascular changes in Alzheimer's disease mice by photoacoustic imaging

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Journal of Innovative Optical Health Sciences 2024年第6期17卷 29-40页

作者： Xi Li Zhongyang Zhang hua Shi Feifan zhou Key Laboratory of Biomedical Engineering of Hainan Province School of Biomedical Engineering Hainan University Sanya 572025P.R.China

The cerebral vasculature plays a significant role in the development of Alzheimer's disease(AD),however,the specific association between them remains *** this paper,based on the benefits of photoacoustic imaging(Pai),including label-free,high-resolution,in vivo imaging of vessels,we investigated the structural changes of cerebral vascular in wild-type(WT)mice and AD mice at different ages,analyzed the characteristics of the vascular in different brain regions,and correlated vascular characteristics with cognitive *** results showed that vascular density and vascular branching index in the cortical and frontal regions of both WT and AD mice decreased with ***,vascular lacunarity increased with age,and the changes in vascular structure were more pronounced in AD *** trend of vascular dysfunction aligns with the worsening cognitive dysfunction as the disease ***,we utilized in vivo Pai to analyze the changes in vascular structure during the progression of AD,elucidating the spatial and temporal correlation with cognitive impairment,which will provide more intuitive data for the study of the correlation between cerebrovascular and the development of AD.

关键词： Photoacoustic imaging Alzheimer's disease cerebrovascular vascular network cognitive impairment.

Epigenetic silencing schlafen-11 sensitizes esophageal cancer to ATM inhibitor

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World Journal of Gastrointestinal Oncology 2024年第5期16卷 2060-2073页

作者： Jing zhou Mei-Ying Zhang ai-ai Gao Cheng Zhu Tao He James G Herman Ming-zhou Guo School of Medicine NanKai UniversityTianjin 300071China Department of Gastroenterology and Hepatology The First Medical CenterChinese PLA General HospitalBeijing 100853China Departments of Pathology Characteristic Medical Center of The Chinese People’s Armed Police ForceTianjin 300162China The Hillman Cancer Center University of Pittsburgh Cancer InstitutePittsburghPA 15213United States National Key Laboratory of Kidney Diseases Chinese PLA General HospitalBeijing 100853China

BACKGROUND Targeting DNA damage response(DDR)pathway is a cutting-edge *** has been reported that Schlafen-11(SLFN11)contributes to increase chemosensitivity by participating in ***,the detailed mechanism is *** To investigate the role of SLFN11 in DDR and the application of synthetic lethal in esophageal cancer with SLFN11 *** To reach the purpose,eight esophageal squamous carcinoma cell lines,142 esophageal dysplasia(ED)and 1007 primary esophageal squamous cell carcinoma(ESCC)samples and various techniques were utilized,including methylationspecific polymerase chain reaction,CRISPR/Cas9 technique,Western blot,colony formation assay,and xenograft mouse *** Methylation of SLFN11 was exhibited in 9.15%of(13/142)ED and 25.62%of primary(258/1007)ESCC cases,and its expression was regulated by promoter region ***11 methylation was significantly associated with tumor differentiation and tumor size(both P<0.05).However,no significant associations were observed between promoter region methylation and age,gender,smoking,alcohol consumption,TNM stage,or lymph node *** DNA damaged model induced by low dose cisplatin,SLFN11 was found to activate non-homologous end-joining and ATR/CHK1 signaling pathways,while inhibiting the ATM/CHK2 signaling *** silencing of SLFN11 was found to sensitize the ESCC cells to ATM inhibitor(AZD0156),both in vitro and in *** SLFN11 is frequently methylated in human *** of SLFN11 is sensitive marker of ATM inhibitor in ESCC.

关键词： Schlafen-11 Esophageal squamous cell carcinoma DNA methylation Synthetic lethality AZD0156