Effective motors are crucial for driving astronomical telescopes,especially for those operating in Antarctica,where the harsh environment and operating conditions,including extreme low temperature,ice/snow accumulatio...Effective motors are crucial for driving astronomical telescopes,especially for those operating in Antarctica,where the harsh environment and operating conditions,including extreme low temperature,ice/snow accumulation,low power consumption,and unattended operation,introduce challenges to the design and development of motor drives.We present the design of a permanent magnet synchronous motor suitable for this environment,conducting a quantitative analysis on the impacts of cryogenic conditions on lubricant performance,differential thermal contraction of metallic components,and remanent flux density of neodymium iron boron(N52)permanent magnets.We also implement a labyrinth seal structure,combined with silicone sealing rings,to mitigate ice crystal intrusion risks.Finite element analysis and laboratory tests demonstrate a maximum torque output of 25 Nm.This kind of motor is used in the Antarctic 15 cm Near Infrared Telescope at Dome A,Antarctica.Operation data shows a total encoder feedback error of 0.0678"for the telescope control system with 15"s^(−1)tracking speed at−56.79°C.These results comprehensively validate the high reliability and precision of the motor under the extreme conditions of the polar environment.展开更多
Astronomical site selection work is very hard.Unmanned technologies are important trends and solutions.We present a relatively easy method to plan a high reliability site selection which can extend the time from site ...Astronomical site selection work is very hard.Unmanned technologies are important trends and solutions.We present a relatively easy method to plan a high reliability site selection which can extend the time from site deployment to returning for maintaining by unmanned confirming the site.First,we redefine the reliability of a site selection deployment with the parameter of the trusty time,which means when we must return,and which can be relatively easy for estimating.The redefinition makes the reliability parameter as a Bayesian probability,and can be obtained by estimating besides testing,which makes the evaluation of each device's reliability much easier.Then we use block diagram tools in the Matlab Simulink software to construct structure diagram,and to link each component with relations of parallel,serial,protection,and so on.This makes the whole reliability value can be calculated at the time when we design or plan a site selection.We applied this concept and method in an actual site selection in Lenghu,Qinghai Province,China.The survey practice reveals its effectiveness and simpleness.展开更多
Artificial Intelligence(AI)is an interdisciplinary research field with widespread applications.It aims at developing theoretical,methodological,technological,and applied systems that simulate,enhance,and assist human ...Artificial Intelligence(AI)is an interdisciplinary research field with widespread applications.It aims at developing theoretical,methodological,technological,and applied systems that simulate,enhance,and assist human intelligence.Recently,notable accomplishments of artificial intelligence technology have been achieved in astronomical data processing,establishing this technology as central to numerous astronomical research areas such as radio astronomy,stellar and galactic(Milky Way)studies,exoplanets surveys,cosmology,and solar physics.This article systematically reviews representative applications of artificial intelligence technology to astronomical data processing,with comprehensive description of specific cases:pulsar candidate identification,fast radio burst detection,gravitational wave detection,spectral classification,and radio frequency interference mitigation.Furthermore,it discusses possible future applications to provide perspectives for astronomical research in the artificial intelligence era.展开更多
The Qaidam Basin,as the largest inland basin within the Tibetan Plateau,has accumulated more than 10,000 m of Cenozoic continental sediments.It serves as a crucial research area for documenting Cenozoic climate change...The Qaidam Basin,as the largest inland basin within the Tibetan Plateau,has accumulated more than 10,000 m of Cenozoic continental sediments.It serves as a crucial research area for documenting Cenozoic climate changes and plateau uplift processes in the Asian interior.Additionally,the basin holds vast reserves of oil and gas resources,making high-resolution drilling data invaluable for studying paleoclimate.In this study,the longsequence lacustrine deposits of JS1 drill core across the Shizigou Formation in the Yiliping Depression at the western center of the basin were studied,aiming to establish an astronomical timescale for the Shizigou Formation and investigate the characteristics of paleoclimatic changes during the late Miocene to the Pliocene for the Asian interior.The analysis was carried out using high-resolution natural gamma ray(GR)data sequences,employing techniques such as spectral analysis,filtering,and wavelet analysis in cyclostratigraphy.The results indicated the presence of a stable Milankovitch orbital signal was perfectly recorded in the Shizigou Formation,primarily influenced by eccentricity cycles,with weaker obliquity and precession cycles.Using the stable and continuous 405 ka eccentricity cycle in astronomical tuning,a"floating"astronomical timescale with a duration of 6.1 Ma for the Yiliping depression's Shizigou Formation has been established.With reference to previously established stratigraphic age anchor points,an absolute astronomical timescale(2.5-8.6 Ma)has been ultimately provided for the Shizigou Formation.Simultaneously,a clear 100 ka short eccentricity cycle record has been identified during the Pliocene(5.3-2.5 Ma),which corresponds in time with the aridification within the basin during this Pliocene period.In addition,a comparison of the Pliocene natural gamma ray curve of the Qaidam Basin with global ice volume variations indicated that the basin's aridification was influenced by global cooling,with eccentricity-modulated precession cycles controlling solar radiation and subsequently affecting the evolution of lakes in the arid region of Inner Asia.展开更多
A continuous terrestrial succession was recovered from the Songke-2(SK-2)borehole in the Songliao Basin,Northeastern China.This borehole provides a unique material for further research on the continental paleoclimate ...A continuous terrestrial succession was recovered from the Songke-2(SK-2)borehole in the Songliao Basin,Northeastern China.This borehole provides a unique material for further research on the continental paleoclimate during Cretaceous greenhouse period,following a series of achievements of the Songke-1(SK-1)core.In this study,thorium(Th)logging data were chosen as a paleoclimate proxy to conduct a detailed cyclostratigraphic analysis.The Th series varies quasi-periodically;power spectra and evolutionary fast Fourier transformation(FFT)analysis reveal significant cycles in the Quantou(K2 q),Qingshankou(K2 qn),Yaojia(K2 y)and Nenjiang(K2 n)formations.The ratio of cycle wavelengths in these stratigraphic units is approximately 20:5:2:1,corresponding to long orbital eccentricity(405 kyr),short orbital eccentricity(100 kyr),obliquity(37 kyr),and precession cycles(22.5 kyr and 18.4 kyr).The durations of the K2 n,K2 y,K2 qn and K2 q are estimated as 6.97,1.83,5.30 and 4.52 Myr,respectively,based on the constructed^18.62 Myr"floating"astronomical time scale(ATS).Comparison of the durations between the SK-1 s and SK-2 boreholes exhibits a slight difference of 0.06 Myr and 0.459 Myr for K2 qn and K2 y.Nevertheless,our ATS of K2 n supports the chronostratigraphic frame constructed by the CA-ID-TIMS data of the SK-1 s borehole.This new"floating"ATS provides precise numerical ages for stratigraphic boundaries,biozones and geological events in the Songliao Basin,and can serve as a basis for correlation of strata and events between marine and terrestrial systems.展开更多
One of the clocks that record the Earth history is(quasi-) periodic astronomical cycles.These cycles influence the climate that can be ultimately stored in sedimentary rocks.By cracking these(quasi-) periodic sediment...One of the clocks that record the Earth history is(quasi-) periodic astronomical cycles.These cycles influence the climate that can be ultimately stored in sedimentary rocks.By cracking these(quasi-) periodic sedimentation signals,high resolution astronomical time scale(ATS) can be obtained.Paleoclimate proxies are widely used to extract astronomical cycles.However different proxies may respond differently to astronomical signals and nonastronomical noises including tectonics,diagenesis,and measurement error among others.Astronomical time scale constructed based on a single proxy where its signal-to-noise ratio is low may have uncertainty that is difficult to evaluate but can be revealed by utilizing other proxies.Here,we test eight astronomical age models using two astrochro no logical methods from four paleoclimate proxies(i.e.,color reflection L~* and b~*,natural gamma radiation,and bulk density) from the Turonian to the Coniacian of the Cretaceous Period at the Demerara Rise in the equatorial Atlantic.The two astrochronological methods are time calibration using long eccentricity bandpass filtering(E1 bandpass) and tracking the long eccentricity from evolutive harmonic analysis(tracking EHA).The statistical mean and standard deviation of four age models from the four proxies are calculated to construct one integrated age model with age uncertainty in each method.Results demonstrate that extracting astronomical signals from multiple paleoclimate proxies is a valid method to estimate age model uncertainties.Anchored at the Cenomanian/Turonian boundary with an age of 93.9 ± 0.15 Ma from biostratigraphy,the ages for CC11/CC12(calcareous nannofossil zones),Turonian/Coniacian(CC12/CC13),CC13/CC14,and Coniacian/Santonian boundaries are 91.25±0.20 Ma,89.87±0.20 Ma,86.36±0.33 Ma,and 86.03±0.32 Ma in E1 bandpass method,compared with 91.17±0.36 Ma,89.74±0.38 Ma,86.13±1.31 Ma,and 85.80±1.33 Ma respectively in tracking EHA method.These results are consistent with previous studies within error and provide a reliable estimation of uncertainties of the ages.展开更多
Sediments in the Liushagang Formation of Late Eocene form a group of key hydrocarbon play fairways in the Beibuwan Basin,South China Sea.As an important reservoir-forming combination,the Liushagang Formation consists ...Sediments in the Liushagang Formation of Late Eocene form a group of key hydrocarbon play fairways in the Beibuwan Basin,South China Sea.As an important reservoir-forming combination,the Liushagang Formation consists of deltaic siliciclastic and show clear sedimentary cyclicity.According to paleontology research and stratigraphic correlation,the boundary between Liushagang Formation(Els)and Weizhou Formation(Ewz)is regarded as the Eocene-Oligocene boundary.The oxygen isotope dating for well cores from the top of the first Member of Liushagang Formation(Els1)and the bottom of the third Member of Weizhou Formation(Ewz3)give an isochron age of 35.2 Ma.Here,we use GR logging data as a paleoenvironmental proxy to conduct a detailed cyclostratigraphic study of the Els1 in the Bailian Sag,Fushan Depression.Power spectra,evolutionary fast Fourier transformation and wavelet analysis all reveal significant sedimentary cycles in Els1.The ratios of cycle wavelengths in these stratigraphic units are 21?5?2.8?1.2?1,and are interpreted as Milankovitch cycles of 400 ka and 96 ka eccentricity,52 ka obliquity,22ka and 19 ka precession cycles,respectively.An astronomical time scale is established by tuning filtered 96 ka eccentricity cycles to a target curve of Well L2 in the Bailian Sag.Based on regional stratigraphic framework,combined with seismic,cores and logging data,the HST of the first member of the Liushagang Formation(Els1)delta in Well L2 was divided into six parasequence sets named Ps1-Ps6.According to the spectrum analysis by Simple Lomb periodogram from PAST program packages,the sediment accumulation rate of each parasequence sets first increased and then decreased as time went by.The sediment accumulation rate of Ps4 reached the maximum(0.127 m/ka)during the most prosperous period of delta prograding.Finally,the duration of each period of parasequence sets and more accurate geological age were calculated on the basis of sediment accumulation rate.The ages of each depth are precisely estimated and provide new constraints on the Late Eocene.展开更多
We installed two sets of Astronomical Site Monitoring Systems(ASMSs)at Lijiang Observatory(GMG),for the running of the 2.4-meter Lijiang optical telescope(LJT)and the 1.6-meter Multi-channel Photometric Survey Telesco...We installed two sets of Astronomical Site Monitoring Systems(ASMSs)at Lijiang Observatory(GMG),for the running of the 2.4-meter Lijiang optical telescope(LJT)and the 1.6-meter Multi-channel Photometric Survey Telescope(Mephisto).The Mephisto is under construction.The ASMS has been running on robotic mode since 2017.The core instruments:Cloud Sensor,All-Sky Camera and AutonomousDIMM that are developed by our group,together with the commercial Meteorological Station and Sky Quality Meter,are combined into the astronomical optical site monitoring system.The new Cloud Sensor's Cloud-Clear Relationship is presented for the first time,which is used to calculate the All-Sky cloud cover.We designed the Autonomous-DIMM located on a tower,with the same height as LJT.The seeing data have been observed for a full year.ASMS's data for the year 2019 are also analysed in detail,which are valuable to observers.展开更多
Based on the developed distributed model for calculating astronomical solar radiation (ASR), monthly ASR with a resolution of 1 km×1 km for the rugged terrains of Yellow River Basin was calculated, with DEM data ...Based on the developed distributed model for calculating astronomical solar radiation (ASR), monthly ASR with a resolution of 1 km×1 km for the rugged terrains of Yellow River Basin was calculated, with DEM data as the general characterization of terrain. This model gives an all-sided consideration on factors that influence the ASR. Results suggest that (1) Annual ASR has a progressive decrease trend from south to north; (2) the magnitude order of seasonal ASR is: summer>spring>autumn>winter; (3) topographical factors have robust effect on the spatial distribution of ASR, particularly in winter when a lower sun elevation angle exists; (4) the ASR of slopes with a sunny exposure is generally 2 or 3 times that of slopes with a shading exposure and the extreme difference of ASR for different terrains is over 10 times in January; (5) the spatial differences of ASR are relatively small in summer when a higher sun elevation angle exists and the extreme difference of ASR for different terrains is only 16% in July; and (6) the sequence of topographical influence strength is: winter>autumn>spring>summer.展开更多
The reflecting Schmidt plate system of the large sky area multi-object fiberspectroscopic telescope (LAMOST) serves active optical correction with a reflecting surface ofsegmented mirror. An azimuth-altitude mounting ...The reflecting Schmidt plate system of the large sky area multi-object fiberspectroscopic telescope (LAMOST) serves active optical correction with a reflecting surface ofsegmented mirror. An azimuth-altitude mounting is adopted with two self-aligning ball bearings foraltitude axis and hydrostatic bearings for azimuth. With static and modal analyses, finite elementmodeling of the full Schmidt plate system is discussed. Conventional seismic response spectrum hasbeen adapted for particular application for telescope engineering before a seismic response spectrumanalysis is performed, and results have confirmed that the design of the reflecting Schmidt platemanifests good performance and can survive the seismic intensity of up to 7 magnitude specified bytechnical requirements.展开更多
Astronomical cross-matching is a basic method for aggregating the observational data of different wavelengths. By data aggregation, the properties of astronomical objects can be understood comprehensively. Aiming at d...Astronomical cross-matching is a basic method for aggregating the observational data of different wavelengths. By data aggregation, the properties of astronomical objects can be understood comprehensively. Aiming at decreasing the time consumed on I/O operations, several improved methods are introduced, including a processing flow based on the boundary growing model, which can reduce the database query operations; a concept of the biggest growing block and its determination which can improve the performance of task partition and resolve data-sparse problem; and a fast bitwise algorithm to compute the index numbers of the neighboring blocks, which is a significant efficiency guarantee. Experiments show that the methods can effectively speed up cross-matching on both sparse datasets and high-density datasets.展开更多
The Hanjiang Formation of Langhian age （middle Miocene） in the Pearl River Mouth Basin （PRMB）, South China Sea consists of deltaic siliciclastic and neritic shelf carbonate rhythmic alternations, which form one of...The Hanjiang Formation of Langhian age （middle Miocene） in the Pearl River Mouth Basin （PRMB）, South China Sea consists of deltaic siliciclastic and neritic shelf carbonate rhythmic alternations, which form one of the potential reservoirs of the basin. To improve stratigraphic resolutions for hydrocarbon prospecting and exploration in the basin, the present study undertakes spectral analysis of high-resolution natural gamma-ray （NGR） well-logging record to determine the dominant frequency components and test whether Milankovitch orbital signals are recorded in rhythmic successions. Analytical results indicate the orbital cycles of precession （~19 ka and ~23 ka）, obliquity （-41 ka）, and eccentricity （~100 ka and --405 ka）, which provide the strong evidence for astronomically driven climate changes in the rhythmic alternation successions. Within biochronological constraint, a high-resolution astronomical timescale was constructed through the astronomical tuning of the NGR record to recent astronomically calculated variation of Earth＇s orbit. The astronomically tuned timescale can be applied to calculate astronomical ages for the geological events and bioevents recognized throughout the period. The first downhole occurrences of foraminifers Globorotalia peripheroronda and Globigerinoides sicanus are dated at 14.546 Ma and 14.919 Ma, respectively, which are slightly different from earlier estimates in the South China Sea. When compared with the global sea-level change chart, the astronomical estimate for the sequences recognized based on microfossil distributions have the same end time but the different initiation time. This is probably due to the local or regional tectonic activities superimposed on eustatic rise which postponed the effect of global sea-level rising. Astronomical timescale also resolves the depositional evolution history for the Langhian Stage （middle Miocene） with a variation that strongly resembles that of Earth＇s orbital eccentricity predicted from 13.65 Ma to 15.97 Ma. We infer that the main factor controlling the variability of the sedimentation rate in the Hanjiang Formation is related to the ^-405-ka-period eccentricity.展开更多
Astronomical knowledge entities,such as celestial object identifiers,are crucial for literature retrieval and knowledge graph construction,and other research and applications in the field of astronomy.Traditional meth...Astronomical knowledge entities,such as celestial object identifiers,are crucial for literature retrieval and knowledge graph construction,and other research and applications in the field of astronomy.Traditional methods of extracting knowledge entities from texts face numerous challenging obstacles that are difficult to overcome.Consequently,there is a pressing need for improved methods to efficiently extract them.This study explores the potential of pre-trained Large Language Models(LLMs)to perform astronomical knowledge entity extraction(KEE)task from astrophysical journal articles using prompts.We propose a prompting strategy called PromptKEE,which includes five prompt elements,and design eight combination prompts based on them.We select four representative LLMs(Llama-2-70B,GPT-3.5,GPT-4,and Claude 2)and attempt to extract the most typical astronomical knowledge entities,celestial object identifiers and telescope names,from astronomical journal articles using these eight combination prompts.To accommodate their token limitations,we construct two data sets:the full texts and paragraph collections of 30 articles.Leveraging the eight prompts,we test on full texts with GPT-4and Claude 2,on paragraph collections with all LLMs.The experimental results demonstrate that pre-trained LLMs show significant potential in performing KEE tasks,but their performance varies on the two data sets.Furthermore,we analyze some important factors that influence the performance of LLMs in entity extraction and provide insights for future KEE tasks in astrophysical articles using LLMs.Finally,compared to other methods of KEE,LLMs exhibit strong competitiveness in multiple aspects.展开更多
To improve the efficiency of the attribute reduction, we present an attribute reduction algorithm based on background knowledge and information entropy by making use of background knowledge from research fields. Under...To improve the efficiency of the attribute reduction, we present an attribute reduction algorithm based on background knowledge and information entropy by making use of background knowledge from research fields. Under the condition of known background knowledge, the algorithm can not only greatly improve the efficiency of attribute reduction, but also avoid the defection of information entropy partial to attribute with much value. The experimental result verifies that the algorithm is effective. In the end, the algorithm produces better results when applied in the classification of the star spectra data.展开更多
An astronomical observatory is the core component of any astronomical research facility that connects astronomers with their lab: the Cosmos. The research quality of an astronomical facility is rooted in the precision...An astronomical observatory is the core component of any astronomical research facility that connects astronomers with their lab: the Cosmos. The research quality of an astronomical facility is rooted in the precision of data, collected by its observatory. For optimal performance, an observatory is sited while considering certain astronomical, environmental, geological and social parameters. This study aims to identify the potential sites in Pakistan for locating an optical-astronomical observatory using the Multicriteria Decision Analysis(MCDA) technique. The study uses the Analytic Hierarchy Process(AHP) for deriving the influence weights of nine evaluation criteria: Photometric Night Fraction;Night-time Sky Brightness;Sky Transparency;Aerosol Concentration;Altitude;Terrain Slope;Accessibility;Seismic Vulnerability;and Landuse/Land Cover. On the basis of experts’ opinions and previous studies, the evaluation criteria have been ordered in two possible preference sequences for identifying their influence weights with respect to each other for taking part in MCDA. Consequently, the process of MCDA identified certain areas with respect to each preference sequence, whereas some areas were found to be suitable according to both preference sequences. The study synchronizes the required eclectic data into an evaluation matrix that augments the process of astronomical site selection. In the future, this study will be useful for astronomical societies and for furthering astronomical research in the country.展开更多
The late Permian(Lopingian)was a crucial climate transition period from the late Paleozoic Ice Age to the early Triassic of exceptionally high temperatures.However,the origins of the third-order sea-level changes duri...The late Permian(Lopingian)was a crucial climate transition period from the late Paleozoic Ice Age to the early Triassic of exceptionally high temperatures.However,the origins of the third-order sea-level changes during the Lopingian Epoch remain unclear.Here,we presented astronomically calibrated gamma-ray(GR)log and non-U GR(computed gamma ray or CGR)curves from the clastic and carbonate successions of well GFD-1 in the Pingle Depression of South China for studying the sea-level oscillations during the Lopingian.Spectral analyses of the 405 kyr-calibrated GR and CGR time data revealed periodicities close to about 405,about 100,about 44.2,about 35.1,about 21,and about 17.5 kyr,supporting the existence of Milankovitch forcing in the sedimentary records.A high-resolution astronomical time scale and high-resolution sedimentation rate curve of the Lopingian from well GFD-1 were constructed by cyclostratigraphic analysis.The eccentricity and obliquity amplitude modulation cycles suggested long periodicities of about 2.4 and about 1.2 myr,respectively.In the Wuchiapingian greenhouse of the Lopingian,the about 2.4 myr eccentricity oscillation controlled‘weak’glacio-eustasy and/or aquifer eustatic changes related to the global third-order sea-level changes and that a lowstand(W2)was initiated by an eccentricity oscillation minimum.In contrast,during the Changhsingian,which exhibited a cooling event,an about 1.2 myr obliquity cycle was probably strong,with the sea-level records highlighting the link between the‘icehouse’sea-level lowering(C2 and C1)and the obliquity nodes.Moreover,dynamic sedimentary noise model as an indicator of sea-level showed local third-order sea-level variations,the coevolution trends in the orbital power,global and local sea-level changes,and sedimentation rate had significant implications for establishing the global nature and synchronicity of these million-year-scale eustatic records and reconstructing the temporal depositional history at a regional scale.In addition,the volcanism and tectonism that continued into the early-middle Wuchiapingian probably led to a series of climate changes that drove the hydrological cycles not paced by the Milankovitch cycles.展开更多
Fine-grained lacustrine sedimentation controlled by astronomical cycles remains a research weakness in sedimentology studies,as most studies have concentrated on how astronomical cycles affect the normal lacustrine fi...Fine-grained lacustrine sedimentation controlled by astronomical cycles remains a research weakness in sedimentology studies,as most studies have concentrated on how astronomical cycles affect the normal lacustrine fine-grained sedimentation,but how they affect the lacustrine fine-grained event sedimen-tation has been rarely studied.Therefore,this work researched the characteristics of event sedimentation by systematically observing the cores from 30 cored wells in the Shahejie Formation of the Dongying Sag at a depth of over 1800 m,with more than 4000 thin sections being authenticated and over 1000 whole rocks being analyzed by X-ray diffraction(XRD).The research object was the Chunshang Sub-member of Upper Es_(4) in the Fanye 1 well,as it had the most comprehensive analysis data and underwent the most continuous coring.We divided astronomical cycles into different orders and made corresponding curves using the gamma-ray(GR)curve,spectral analysis,power spectrum estimation,and module extreme values,there were 6 long eccentricity periods,22 short eccentricity periods,65.5 obliquity cycles,and 110.5 precession cycles in this sub-member.On this basis,this study analyzed the control of astronomical cycles on the lacustrine fine-grained event sedimentation,and the research shows deposits were developed by slide-slump,turbidities,hyperpycnites,and tempestites in the Chunshang Sub-member of the Upper Es_(4),with higher long eccentricity,the monsoon climate contributes to the formation of storm currents,while with lower long eccentricity,the surface deposits are severely eroded by rivers and rainfalls,thus developing the slide-slump,turbidities,and hyperpycnites.The relationship between the lacustrine fine-grained event sedimentation and astronomical cycles was studied in this case study,which can promote research on fine-grained sedimentary rocks in genetic dynamics and boost the theoretical and disciplinary development in fine-grained sedimentology.展开更多
With the application of advanced astronomical technologies, equipments and methods all over the world, astronomical observations cover the range from radio, infrared, visible light, ultraviolet, X-ray and gamma-ray ba...With the application of advanced astronomical technologies, equipments and methods all over the world, astronomical observations cover the range from radio, infrared, visible light, ultraviolet, X-ray and gamma-ray bands, and enter into the era of full wavelength astronomy. How to effectively integrate data from different ground- and space-based observation equipments, different observers, different bands and different observation times, requires data fusion technology. In this paper we introduce a cross-match tool that is developed in the Python language, is based on the PostgreSQL database and uses Q3C as the core index, facilitating the cross-match work of massive astronomical data. It provides four different cross- match functions, namely： （I） cross-match of the custom error range; （II） cross-match of catalog errors; （III） cross-match based on the elliptic error range; （IV） cross-match of the nearest neighbor algorithm. The resulting cross-matched set provides a good foundation for subsequent data mining and statistics based on multiwavelength data. The most advantageous aspect of this tool is a user-oriented tool applied locally by users. By means of this tool, users can easily create their own databases, manage their own data and cross- match databases according to their requirements. In addition, this tool is also able to transfer data from one database into another database. More importantly, it is easy to get started with the tool and it can be used by astronomers without writing any code.展开更多
This article discusses the development of astronomical tables in ancient China based on the calendrical chapter titled“Lü-li zhi”律曆志(Monograph on harmonics and calendrical astronomy)in official histories.Aft...This article discusses the development of astronomical tables in ancient China based on the calendrical chapter titled“Lü-li zhi”律曆志(Monograph on harmonics and calendrical astronomy)in official histories.After surveying various types of astral scientific tables in ancient China and their layouts,this paper discusses the characteristics and adoption of“licheng”立成tables,a specific kind of pick-up table that seems to have come into use in the Sui period(581–618)and to have been widespread from the Tang period(618–907)onward.The emergence of licheng tables relates largely to the internal development of ancient Chinese astronomy,but they were also probably inspired by auspicial tables and foreign astronomical tables.By comparing tables recorded in the“Lü-li zhi”and the existing licheng tables,we find that most licheng were deleted during the compilation of“Lü-li zhi”to reduce the number of volumes.Moreover,this paper discusses several common solutions used to compress the size of tables in“Lü-li zhi.”The adoption of licheng tables into the ancient Chinese astral sciences and the reformatting of them in“Lü-li zhi”give us a different perspective for understanding the development of ancient Chinese astronomical tables and the compilation of the calendrical portion of official histories.展开更多
We will introduce the construction and design of a new simultaneous three-channel multicolor CCD photometer.This photometer has been mounted on the 1.2 m telescope at Jilin Astronomical Observatory,and is applied to s...We will introduce the construction and design of a new simultaneous three-channel multicolor CCD photometer.This photometer has been mounted on the 1.2 m telescope at Jilin Astronomical Observatory,and is applied to study space debris,gamma-ray burst afterglows,asteroids and other rapidly variable objects.As one of the ground follow-up telescopes of the Chinese-French Space-based multi-band astronomical Variable Objects Monitor(SVOM)mission,it appears very essential to evaluate the performance of the photometry system of this photometer,which can achieve simultaneous imaging within a field of view of 21’.5×21’.5,21’.5×21’.5 and21’.3×21’.3 in the Sloan Digital Sky Survey(SDSS)g’,r’,i’bands,respectively.Photometric calibrations were carried out by using plenty of SDSS standard stars,and the relationship between the photometric system and the Johnson-Bessel filter system was also studied.The results of the performance evaluation from observing open cluster M67 are presented.展开更多
基金supported by the Space Debris Resear-ch Project,China(KJSP2020010102)the NationalKey R&D Program of China(2022YFC2807300).
文摘Effective motors are crucial for driving astronomical telescopes,especially for those operating in Antarctica,where the harsh environment and operating conditions,including extreme low temperature,ice/snow accumulation,low power consumption,and unattended operation,introduce challenges to the design and development of motor drives.We present the design of a permanent magnet synchronous motor suitable for this environment,conducting a quantitative analysis on the impacts of cryogenic conditions on lubricant performance,differential thermal contraction of metallic components,and remanent flux density of neodymium iron boron(N52)permanent magnets.We also implement a labyrinth seal structure,combined with silicone sealing rings,to mitigate ice crystal intrusion risks.Finite element analysis and laboratory tests demonstrate a maximum torque output of 25 Nm.This kind of motor is used in the Antarctic 15 cm Near Infrared Telescope at Dome A,Antarctica.Operation data shows a total encoder feedback error of 0.0678"for the telescope control system with 15"s^(−1)tracking speed at−56.79°C.These results comprehensively validate the high reliability and precision of the motor under the extreme conditions of the polar environment.
基金supported by the Investigation of Technological Infrastructure Resources(No.2023FY101101)the National Natural Science Foundation of China(NSFC)(No.11073027 and No.12373104)。
文摘Astronomical site selection work is very hard.Unmanned technologies are important trends and solutions.We present a relatively easy method to plan a high reliability site selection which can extend the time from site deployment to returning for maintaining by unmanned confirming the site.First,we redefine the reliability of a site selection deployment with the parameter of the trusty time,which means when we must return,and which can be relatively easy for estimating.The redefinition makes the reliability parameter as a Bayesian probability,and can be obtained by estimating besides testing,which makes the evaluation of each device's reliability much easier.Then we use block diagram tools in the Matlab Simulink software to construct structure diagram,and to link each component with relations of parallel,serial,protection,and so on.This makes the whole reliability value can be calculated at the time when we design or plan a site selection.We applied this concept and method in an actual site selection in Lenghu,Qinghai Province,China.The survey practice reveals its effectiveness and simpleness.
基金This work is supported by National Key R&D Program of China No.2021YFC2203502 and 2022YFF0711502the National Natural Science Foundation of China(NSFC)(12173077 and 12003062)+5 种基金the Tianshan Innovation Team Plan of Xinjiang Uygur Autonomous Region(2022D14020)the Tianshan Talent Project of Xinjiang Uygur Autonomous Region(2022TSYCCX0095)the Scientific Instrument Developing Project of the Chinese Academy of Sciences,Grant No.PTYQ2022YZZD01China National Astronomical Data Center(NADC)the Operation,Maintenance and Upgrading Fund for Astronomical Telescopes and Facility Instruments,budgeted from the Ministry of Finance of China(MOF)and administrated by the Chinese Academy of Sciences(CAS)Natural Science Foundation of Xinjiang Uygur Autonomous Region(2022D01A360).
文摘Artificial Intelligence(AI)is an interdisciplinary research field with widespread applications.It aims at developing theoretical,methodological,technological,and applied systems that simulate,enhance,and assist human intelligence.Recently,notable accomplishments of artificial intelligence technology have been achieved in astronomical data processing,establishing this technology as central to numerous astronomical research areas such as radio astronomy,stellar and galactic(Milky Way)studies,exoplanets surveys,cosmology,and solar physics.This article systematically reviews representative applications of artificial intelligence technology to astronomical data processing,with comprehensive description of specific cases:pulsar candidate identification,fast radio burst detection,gravitational wave detection,spectral classification,and radio frequency interference mitigation.Furthermore,it discusses possible future applications to provide perspectives for astronomical research in the artificial intelligence era.
基金supported by the Second Tibetan Plateau Scientific Expedition(STEP)program(2019QZKK0704)the National Natural Science Foundation of China(grant number 42272029)the"Light of West China"Program of the Chinese Academy of Sciences(xbzglzb2022025).
文摘The Qaidam Basin,as the largest inland basin within the Tibetan Plateau,has accumulated more than 10,000 m of Cenozoic continental sediments.It serves as a crucial research area for documenting Cenozoic climate changes and plateau uplift processes in the Asian interior.Additionally,the basin holds vast reserves of oil and gas resources,making high-resolution drilling data invaluable for studying paleoclimate.In this study,the longsequence lacustrine deposits of JS1 drill core across the Shizigou Formation in the Yiliping Depression at the western center of the basin were studied,aiming to establish an astronomical timescale for the Shizigou Formation and investigate the characteristics of paleoclimatic changes during the late Miocene to the Pliocene for the Asian interior.The analysis was carried out using high-resolution natural gamma ray(GR)data sequences,employing techniques such as spectral analysis,filtering,and wavelet analysis in cyclostratigraphy.The results indicated the presence of a stable Milankovitch orbital signal was perfectly recorded in the Shizigou Formation,primarily influenced by eccentricity cycles,with weaker obliquity and precession cycles.Using the stable and continuous 405 ka eccentricity cycle in astronomical tuning,a"floating"astronomical timescale with a duration of 6.1 Ma for the Yiliping depression's Shizigou Formation has been established.With reference to previously established stratigraphic age anchor points,an absolute astronomical timescale(2.5-8.6 Ma)has been ultimately provided for the Shizigou Formation.Simultaneously,a clear 100 ka short eccentricity cycle record has been identified during the Pliocene(5.3-2.5 Ma),which corresponds in time with the aridification within the basin during this Pliocene period.In addition,a comparison of the Pliocene natural gamma ray curve of the Qaidam Basin with global ice volume variations indicated that the basin's aridification was influenced by global cooling,with eccentricity-modulated precession cycles controlling solar radiation and subsequently affecting the evolution of lakes in the arid region of Inner Asia.
基金supported by the National Natural Science Foundation of China(41790451,41925010,and 41688103)National Key R&D Program of China(2019YFC0605403)the subject development project of RIPED(yjkt2019-3).
文摘A continuous terrestrial succession was recovered from the Songke-2(SK-2)borehole in the Songliao Basin,Northeastern China.This borehole provides a unique material for further research on the continental paleoclimate during Cretaceous greenhouse period,following a series of achievements of the Songke-1(SK-1)core.In this study,thorium(Th)logging data were chosen as a paleoclimate proxy to conduct a detailed cyclostratigraphic analysis.The Th series varies quasi-periodically;power spectra and evolutionary fast Fourier transformation(FFT)analysis reveal significant cycles in the Quantou(K2 q),Qingshankou(K2 qn),Yaojia(K2 y)and Nenjiang(K2 n)formations.The ratio of cycle wavelengths in these stratigraphic units is approximately 20:5:2:1,corresponding to long orbital eccentricity(405 kyr),short orbital eccentricity(100 kyr),obliquity(37 kyr),and precession cycles(22.5 kyr and 18.4 kyr).The durations of the K2 n,K2 y,K2 qn and K2 q are estimated as 6.97,1.83,5.30 and 4.52 Myr,respectively,based on the constructed^18.62 Myr"floating"astronomical time scale(ATS).Comparison of the durations between the SK-1 s and SK-2 boreholes exhibits a slight difference of 0.06 Myr and 0.459 Myr for K2 qn and K2 y.Nevertheless,our ATS of K2 n supports the chronostratigraphic frame constructed by the CA-ID-TIMS data of the SK-1 s borehole.This new"floating"ATS provides precise numerical ages for stratigraphic boundaries,biozones and geological events in the Songliao Basin,and can serve as a basis for correlation of strata and events between marine and terrestrial systems.
基金.This study was supported by NSF CAREERaward to Stephen R.Meyers (EAR-1151438)partially supported by the NSF Grant with No.1835717
文摘One of the clocks that record the Earth history is(quasi-) periodic astronomical cycles.These cycles influence the climate that can be ultimately stored in sedimentary rocks.By cracking these(quasi-) periodic sedimentation signals,high resolution astronomical time scale(ATS) can be obtained.Paleoclimate proxies are widely used to extract astronomical cycles.However different proxies may respond differently to astronomical signals and nonastronomical noises including tectonics,diagenesis,and measurement error among others.Astronomical time scale constructed based on a single proxy where its signal-to-noise ratio is low may have uncertainty that is difficult to evaluate but can be revealed by utilizing other proxies.Here,we test eight astronomical age models using two astrochro no logical methods from four paleoclimate proxies(i.e.,color reflection L~* and b~*,natural gamma radiation,and bulk density) from the Turonian to the Coniacian of the Cretaceous Period at the Demerara Rise in the equatorial Atlantic.The two astrochronological methods are time calibration using long eccentricity bandpass filtering(E1 bandpass) and tracking the long eccentricity from evolutive harmonic analysis(tracking EHA).The statistical mean and standard deviation of four age models from the four proxies are calculated to construct one integrated age model with age uncertainty in each method.Results demonstrate that extracting astronomical signals from multiple paleoclimate proxies is a valid method to estimate age model uncertainties.Anchored at the Cenomanian/Turonian boundary with an age of 93.9 ± 0.15 Ma from biostratigraphy,the ages for CC11/CC12(calcareous nannofossil zones),Turonian/Coniacian(CC12/CC13),CC13/CC14,and Coniacian/Santonian boundaries are 91.25±0.20 Ma,89.87±0.20 Ma,86.36±0.33 Ma,and 86.03±0.32 Ma in E1 bandpass method,compared with 91.17±0.36 Ma,89.74±0.38 Ma,86.13±1.31 Ma,and 85.80±1.33 Ma respectively in tracking EHA method.These results are consistent with previous studies within error and provide a reliable estimation of uncertainties of the ages.
基金Projects(41472084,41172123) supported by the National Natural Science Foundation of China
文摘Sediments in the Liushagang Formation of Late Eocene form a group of key hydrocarbon play fairways in the Beibuwan Basin,South China Sea.As an important reservoir-forming combination,the Liushagang Formation consists of deltaic siliciclastic and show clear sedimentary cyclicity.According to paleontology research and stratigraphic correlation,the boundary between Liushagang Formation(Els)and Weizhou Formation(Ewz)is regarded as the Eocene-Oligocene boundary.The oxygen isotope dating for well cores from the top of the first Member of Liushagang Formation(Els1)and the bottom of the third Member of Weizhou Formation(Ewz3)give an isochron age of 35.2 Ma.Here,we use GR logging data as a paleoenvironmental proxy to conduct a detailed cyclostratigraphic study of the Els1 in the Bailian Sag,Fushan Depression.Power spectra,evolutionary fast Fourier transformation and wavelet analysis all reveal significant sedimentary cycles in Els1.The ratios of cycle wavelengths in these stratigraphic units are 21?5?2.8?1.2?1,and are interpreted as Milankovitch cycles of 400 ka and 96 ka eccentricity,52 ka obliquity,22ka and 19 ka precession cycles,respectively.An astronomical time scale is established by tuning filtered 96 ka eccentricity cycles to a target curve of Well L2 in the Bailian Sag.Based on regional stratigraphic framework,combined with seismic,cores and logging data,the HST of the first member of the Liushagang Formation(Els1)delta in Well L2 was divided into six parasequence sets named Ps1-Ps6.According to the spectrum analysis by Simple Lomb periodogram from PAST program packages,the sediment accumulation rate of each parasequence sets first increased and then decreased as time went by.The sediment accumulation rate of Ps4 reached the maximum(0.127 m/ka)during the most prosperous period of delta prograding.Finally,the duration of each period of parasequence sets and more accurate geological age were calculated on the basis of sediment accumulation rate.The ages of each depth are precisely estimated and provide new constraints on the Late Eocene.
基金the National Natural Science Foundation of China(NSFC,Grant Nos.11991051,11203073,11573067,11873092 and 11803087)the CAS“Light of West China”Program(No.Y8XB018001)。
文摘We installed two sets of Astronomical Site Monitoring Systems(ASMSs)at Lijiang Observatory(GMG),for the running of the 2.4-meter Lijiang optical telescope(LJT)and the 1.6-meter Multi-channel Photometric Survey Telescope(Mephisto).The Mephisto is under construction.The ASMS has been running on robotic mode since 2017.The core instruments:Cloud Sensor,All-Sky Camera and AutonomousDIMM that are developed by our group,together with the commercial Meteorological Station and Sky Quality Meter,are combined into the astronomical optical site monitoring system.The new Cloud Sensor's Cloud-Clear Relationship is presented for the first time,which is used to calculate the All-Sky cloud cover.We designed the Autonomous-DIMM located on a tower,with the same height as LJT.The seeing data have been observed for a full year.ASMS's data for the year 2019 are also analysed in detail,which are valuable to observers.
基金Major State Basic Research Development Program of ChinaNo.G19990436-01 No.G20000779
文摘Based on the developed distributed model for calculating astronomical solar radiation (ASR), monthly ASR with a resolution of 1 km×1 km for the rugged terrains of Yellow River Basin was calculated, with DEM data as the general characterization of terrain. This model gives an all-sided consideration on factors that influence the ASR. Results suggest that (1) Annual ASR has a progressive decrease trend from south to north; (2) the magnitude order of seasonal ASR is: summer>spring>autumn>winter; (3) topographical factors have robust effect on the spatial distribution of ASR, particularly in winter when a lower sun elevation angle exists; (4) the ASR of slopes with a sunny exposure is generally 2 or 3 times that of slopes with a shading exposure and the extreme difference of ASR for different terrains is over 10 times in January; (5) the spatial differences of ASR are relatively small in summer when a higher sun elevation angle exists and the extreme difference of ASR for different terrains is only 16% in July; and (6) the sequence of topographical influence strength is: winter>autumn>spring>summer.
基金This project is supported by National Key Project of China
文摘The reflecting Schmidt plate system of the large sky area multi-object fiberspectroscopic telescope (LAMOST) serves active optical correction with a reflecting surface ofsegmented mirror. An azimuth-altitude mounting is adopted with two self-aligning ball bearings foraltitude axis and hydrostatic bearings for azimuth. With static and modal analyses, finite elementmodeling of the full Schmidt plate system is discussed. Conventional seismic response spectrum hasbeen adapted for particular application for telescope engineering before a seismic response spectrumanalysis is performed, and results have confirmed that the design of the reflecting Schmidt platemanifests good performance and can survive the seismic intensity of up to 7 magnitude specified bytechnical requirements.
基金Supported by National Natural Science Foundation of China (No.10978016)Natural Science Foundation of Tianjin (No. 08JCZDJC19700)Key Technologies Research and Development Program of Tianjin (No.09ZCKFGX00400)
文摘Astronomical cross-matching is a basic method for aggregating the observational data of different wavelengths. By data aggregation, the properties of astronomical objects can be understood comprehensively. Aiming at decreasing the time consumed on I/O operations, several improved methods are introduced, including a processing flow based on the boundary growing model, which can reduce the database query operations; a concept of the biggest growing block and its determination which can improve the performance of task partition and resolve data-sparse problem; and a fast bitwise algorithm to compute the index numbers of the neighboring blocks, which is a significant efficiency guarantee. Experiments show that the methods can effectively speed up cross-matching on both sparse datasets and high-density datasets.
基金supported by Australian Research Council discovery grant(DP0770938 to ZQC)National Science and Technology Major Project (2011ZX05001-001-006)
文摘The Hanjiang Formation of Langhian age （middle Miocene） in the Pearl River Mouth Basin （PRMB）, South China Sea consists of deltaic siliciclastic and neritic shelf carbonate rhythmic alternations, which form one of the potential reservoirs of the basin. To improve stratigraphic resolutions for hydrocarbon prospecting and exploration in the basin, the present study undertakes spectral analysis of high-resolution natural gamma-ray （NGR） well-logging record to determine the dominant frequency components and test whether Milankovitch orbital signals are recorded in rhythmic successions. Analytical results indicate the orbital cycles of precession （~19 ka and ~23 ka）, obliquity （-41 ka）, and eccentricity （~100 ka and --405 ka）, which provide the strong evidence for astronomically driven climate changes in the rhythmic alternation successions. Within biochronological constraint, a high-resolution astronomical timescale was constructed through the astronomical tuning of the NGR record to recent astronomically calculated variation of Earth＇s orbit. The astronomically tuned timescale can be applied to calculate astronomical ages for the geological events and bioevents recognized throughout the period. The first downhole occurrences of foraminifers Globorotalia peripheroronda and Globigerinoides sicanus are dated at 14.546 Ma and 14.919 Ma, respectively, which are slightly different from earlier estimates in the South China Sea. When compared with the global sea-level change chart, the astronomical estimate for the sequences recognized based on microfossil distributions have the same end time but the different initiation time. This is probably due to the local or regional tectonic activities superimposed on eustatic rise which postponed the effect of global sea-level rising. Astronomical timescale also resolves the depositional evolution history for the Langhian Stage （middle Miocene） with a variation that strongly resembles that of Earth＇s orbital eccentricity predicted from 13.65 Ma to 15.97 Ma. We infer that the main factor controlling the variability of the sedimentation rate in the Hanjiang Formation is related to the ^-405-ka-period eccentricity.
基金supported by the National Natural Science Foundation of China(NSFC,Grant Nos.12273077,72101068,12373110,and 12103070)National Key Research and Development Program of China under grants(2022YFF0712400,2022YFF0711500)+2 种基金the 14th Five-year Informatization Plan of Chinese Academy of Sciences(CAS-WX2021SF-0204)supported by Astronomical Big Data Joint Research Centerco-founded by National Astronomical Observatories,Chinese Academy of Sciences and Alibaba Cloud。
文摘Astronomical knowledge entities,such as celestial object identifiers,are crucial for literature retrieval and knowledge graph construction,and other research and applications in the field of astronomy.Traditional methods of extracting knowledge entities from texts face numerous challenging obstacles that are difficult to overcome.Consequently,there is a pressing need for improved methods to efficiently extract them.This study explores the potential of pre-trained Large Language Models(LLMs)to perform astronomical knowledge entity extraction(KEE)task from astrophysical journal articles using prompts.We propose a prompting strategy called PromptKEE,which includes five prompt elements,and design eight combination prompts based on them.We select four representative LLMs(Llama-2-70B,GPT-3.5,GPT-4,and Claude 2)and attempt to extract the most typical astronomical knowledge entities,celestial object identifiers and telescope names,from astronomical journal articles using these eight combination prompts.To accommodate their token limitations,we construct two data sets:the full texts and paragraph collections of 30 articles.Leveraging the eight prompts,we test on full texts with GPT-4and Claude 2,on paragraph collections with all LLMs.The experimental results demonstrate that pre-trained LLMs show significant potential in performing KEE tasks,but their performance varies on the two data sets.Furthermore,we analyze some important factors that influence the performance of LLMs in entity extraction and provide insights for future KEE tasks in astrophysical articles using LLMs.Finally,compared to other methods of KEE,LLMs exhibit strong competitiveness in multiple aspects.
基金Supported by the National Natural Science Foundation of China（No. 60573075）, the National High Technology Research and Development Program of China （No. 2003AA133060） and the Natural Science Foundation of Shanxi Province （No. 200601104）.
文摘To improve the efficiency of the attribute reduction, we present an attribute reduction algorithm based on background knowledge and information entropy by making use of background knowledge from research fields. Under the condition of known background knowledge, the algorithm can not only greatly improve the efficiency of attribute reduction, but also avoid the defection of information entropy partial to attribute with much value. The experimental result verifies that the algorithm is effective. In the end, the algorithm produces better results when applied in the classification of the star spectra data.
文摘An astronomical observatory is the core component of any astronomical research facility that connects astronomers with their lab: the Cosmos. The research quality of an astronomical facility is rooted in the precision of data, collected by its observatory. For optimal performance, an observatory is sited while considering certain astronomical, environmental, geological and social parameters. This study aims to identify the potential sites in Pakistan for locating an optical-astronomical observatory using the Multicriteria Decision Analysis(MCDA) technique. The study uses the Analytic Hierarchy Process(AHP) for deriving the influence weights of nine evaluation criteria: Photometric Night Fraction;Night-time Sky Brightness;Sky Transparency;Aerosol Concentration;Altitude;Terrain Slope;Accessibility;Seismic Vulnerability;and Landuse/Land Cover. On the basis of experts’ opinions and previous studies, the evaluation criteria have been ordered in two possible preference sequences for identifying their influence weights with respect to each other for taking part in MCDA. Consequently, the process of MCDA identified certain areas with respect to each preference sequence, whereas some areas were found to be suitable according to both preference sequences. The study synchronizes the required eclectic data into an evaluation matrix that augments the process of astronomical site selection. In the future, this study will be useful for astronomical societies and for furthering astronomical research in the country.
基金This work was supported by a National Natural Science Foundation of China(Grant No.91958210)the Government Finance Level II Project(No.DD20190083)‘the 13th Five-Year Plan’National Science and Technology Major Project(No.2016ZX05034001-003).
文摘The late Permian(Lopingian)was a crucial climate transition period from the late Paleozoic Ice Age to the early Triassic of exceptionally high temperatures.However,the origins of the third-order sea-level changes during the Lopingian Epoch remain unclear.Here,we presented astronomically calibrated gamma-ray(GR)log and non-U GR(computed gamma ray or CGR)curves from the clastic and carbonate successions of well GFD-1 in the Pingle Depression of South China for studying the sea-level oscillations during the Lopingian.Spectral analyses of the 405 kyr-calibrated GR and CGR time data revealed periodicities close to about 405,about 100,about 44.2,about 35.1,about 21,and about 17.5 kyr,supporting the existence of Milankovitch forcing in the sedimentary records.A high-resolution astronomical time scale and high-resolution sedimentation rate curve of the Lopingian from well GFD-1 were constructed by cyclostratigraphic analysis.The eccentricity and obliquity amplitude modulation cycles suggested long periodicities of about 2.4 and about 1.2 myr,respectively.In the Wuchiapingian greenhouse of the Lopingian,the about 2.4 myr eccentricity oscillation controlled‘weak’glacio-eustasy and/or aquifer eustatic changes related to the global third-order sea-level changes and that a lowstand(W2)was initiated by an eccentricity oscillation minimum.In contrast,during the Changhsingian,which exhibited a cooling event,an about 1.2 myr obliquity cycle was probably strong,with the sea-level records highlighting the link between the‘icehouse’sea-level lowering(C2 and C1)and the obliquity nodes.Moreover,dynamic sedimentary noise model as an indicator of sea-level showed local third-order sea-level variations,the coevolution trends in the orbital power,global and local sea-level changes,and sedimentation rate had significant implications for establishing the global nature and synchronicity of these million-year-scale eustatic records and reconstructing the temporal depositional history at a regional scale.In addition,the volcanism and tectonism that continued into the early-middle Wuchiapingian probably led to a series of climate changes that drove the hydrological cycles not paced by the Milankovitch cycles.
基金supported by the Study on Astronomical Stratigraphic Period of Lacustrine Shale and High Resolution Sedimentary Cycle in Logging(41872166)of the National Natural Science Foundation of China and the Exploration and Development Research Institute,Shengli Oilfield Company,SINOPEC.
文摘Fine-grained lacustrine sedimentation controlled by astronomical cycles remains a research weakness in sedimentology studies,as most studies have concentrated on how astronomical cycles affect the normal lacustrine fine-grained sedimentation,but how they affect the lacustrine fine-grained event sedimen-tation has been rarely studied.Therefore,this work researched the characteristics of event sedimentation by systematically observing the cores from 30 cored wells in the Shahejie Formation of the Dongying Sag at a depth of over 1800 m,with more than 4000 thin sections being authenticated and over 1000 whole rocks being analyzed by X-ray diffraction(XRD).The research object was the Chunshang Sub-member of Upper Es_(4) in the Fanye 1 well,as it had the most comprehensive analysis data and underwent the most continuous coring.We divided astronomical cycles into different orders and made corresponding curves using the gamma-ray(GR)curve,spectral analysis,power spectrum estimation,and module extreme values,there were 6 long eccentricity periods,22 short eccentricity periods,65.5 obliquity cycles,and 110.5 precession cycles in this sub-member.On this basis,this study analyzed the control of astronomical cycles on the lacustrine fine-grained event sedimentation,and the research shows deposits were developed by slide-slump,turbidities,hyperpycnites,and tempestites in the Chunshang Sub-member of the Upper Es_(4),with higher long eccentricity,the monsoon climate contributes to the formation of storm currents,while with lower long eccentricity,the surface deposits are severely eroded by rivers and rainfalls,thus developing the slide-slump,turbidities,and hyperpycnites.The relationship between the lacustrine fine-grained event sedimentation and astronomical cycles was studied in this case study,which can promote research on fine-grained sedimentary rocks in genetic dynamics and boost the theoretical and disciplinary development in fine-grained sedimentology.
基金funded by the National Key Basic Research Program of China (2014CB845700)the National Natural Science Foundation of China (NSFC, Grant Nos. 61272272, 11178021 and 11033001)NSFC-Texas A&M University Joint Research Program (No. 11411120219)
文摘With the application of advanced astronomical technologies, equipments and methods all over the world, astronomical observations cover the range from radio, infrared, visible light, ultraviolet, X-ray and gamma-ray bands, and enter into the era of full wavelength astronomy. How to effectively integrate data from different ground- and space-based observation equipments, different observers, different bands and different observation times, requires data fusion technology. In this paper we introduce a cross-match tool that is developed in the Python language, is based on the PostgreSQL database and uses Q3C as the core index, facilitating the cross-match work of massive astronomical data. It provides four different cross- match functions, namely： （I） cross-match of the custom error range; （II） cross-match of catalog errors; （III） cross-match based on the elliptic error range; （IV） cross-match of the nearest neighbor algorithm. The resulting cross-matched set provides a good foundation for subsequent data mining and statistics based on multiwavelength data. The most advantageous aspect of this tool is a user-oriented tool applied locally by users. By means of this tool, users can easily create their own databases, manage their own data and cross- match databases according to their requirements. In addition, this tool is also able to transfer data from one database into another database. More importantly, it is easy to get started with the tool and it can be used by astronomers without writing any code.
文摘This article discusses the development of astronomical tables in ancient China based on the calendrical chapter titled“Lü-li zhi”律曆志(Monograph on harmonics and calendrical astronomy)in official histories.After surveying various types of astral scientific tables in ancient China and their layouts,this paper discusses the characteristics and adoption of“licheng”立成tables,a specific kind of pick-up table that seems to have come into use in the Sui period(581–618)and to have been widespread from the Tang period(618–907)onward.The emergence of licheng tables relates largely to the internal development of ancient Chinese astronomy,but they were also probably inspired by auspicial tables and foreign astronomical tables.By comparing tables recorded in the“Lü-li zhi”and the existing licheng tables,we find that most licheng were deleted during the compilation of“Lü-li zhi”to reduce the number of volumes.Moreover,this paper discusses several common solutions used to compress the size of tables in“Lü-li zhi.”The adoption of licheng tables into the ancient Chinese astral sciences and the reformatting of them in“Lü-li zhi”give us a different perspective for understanding the development of ancient Chinese astronomical tables and the compilation of the calendrical portion of official histories.
基金Supported by the National Natural Science Foundation of China。
文摘We will introduce the construction and design of a new simultaneous three-channel multicolor CCD photometer.This photometer has been mounted on the 1.2 m telescope at Jilin Astronomical Observatory,and is applied to study space debris,gamma-ray burst afterglows,asteroids and other rapidly variable objects.As one of the ground follow-up telescopes of the Chinese-French Space-based multi-band astronomical Variable Objects Monitor(SVOM)mission,it appears very essential to evaluate the performance of the photometry system of this photometer,which can achieve simultaneous imaging within a field of view of 21’.5×21’.5,21’.5×21’.5 and21’.3×21’.3 in the Sloan Digital Sky Survey(SDSS)g’,r’,i’bands,respectively.Photometric calibrations were carried out by using plenty of SDSS standard stars,and the relationship between the photometric system and the Johnson-Bessel filter system was also studied.The results of the performance evaluation from observing open cluster M67 are presented.
