Finding the electromagnetic （EM） counterpart of binary compact star merger, especially the binary neutron star （BNS） merger, is critically important for gravitational wave （GW） astronomy, cosmology and fundament...Finding the electromagnetic （EM） counterpart of binary compact star merger, especially the binary neutron star （BNS） merger, is critically important for gravitational wave （GW） astronomy, cosmology and fundamental physics. On Aug. 17, 2017, Advanced LIGO and Fermi/GBM independently triggered the first BNS merger, GW170817, and its high energy EM counterpart, GRB 170817A, respectively, resulting in a global observation campaign covering gamma-ray, X-ray, UV, optical, IR, radio as well as neutrinos. The High Energy X-ray telescope （HE） onboard Insight-HXMT （Hard X-ray Modulation Telescope） is the unique high-energy gamma-ray telescope that monitored the entire GW localization area and especially the optical counterpart （SSS17a/AT2017gfo） with very large collection area （M000 cm2） and microsecond time resolution in 0.2-5 MeV. In addition, Insight-HXMT quickly implemented a Target of Opportunity （TOO） observation to scan the GW localization area for potential X-ray emission from the GW source. Although Insight-HXMT did not detect any significant high energy （0.2-5 MeV） radiation from GW170817, its observation helped to confirm the unexpected weak and soft nature of GRB 170817A. Meanwhile, Insight-HXMT/HE provides one of the most stringent constraints （-10-7 to 104 erg/cm2/s） for both GRB170817A and any other possible precursor or extended emissions in 0.2-5 MeV, which help us to better understand the properties of EM radiation from this BNS merger. Therefore the observation of Insight-HXMT constitutes an important chapter in the full context of multi-wavelength and multi-messenger observation of this historical GW event.展开更多
In this paper we present the enhanced X-ray Timing and Polarimetry mission—eXTP. eXTP is a space science mission designed to study fundamental physics under extreme conditions of density, gravity and magnetism. The m...In this paper we present the enhanced X-ray Timing and Polarimetry mission—eXTP. eXTP is a space science mission designed to study fundamental physics under extreme conditions of density, gravity and magnetism. The mission aims at determining the equation of state of matter at supra-nuclear density, measuring effects of QED, and understanding the dynamics of matter in strong-field gravity. In addition to investigating fundamental physics, eXTP will be a very powerful observatory for astrophysics that will provide observations of unprecedented quality on a variety of galactic and extragalactic objects. In particular, its wide field monitoring capabilities will be highly instrumental to detect the electro-magnetic counterparts of gravitational wave sources.The paper provides a detailed description of:(1) the technological and technical aspects, and the expected performance of the instruments of the scientific payload;(2) the elements and functions of the mission, from the spacecraft to the ground segment.展开更多
As China’s first X-ray astronomical satellite, the Hard X-ray Modulation Telescope (HXMT), which was dubbed as Insight-HXMT after the launch on June 15, 2017, is a wide-band(1-250 ke V) slat-collimator-based X-ray as...As China’s first X-ray astronomical satellite, the Hard X-ray Modulation Telescope (HXMT), which was dubbed as Insight-HXMT after the launch on June 15, 2017, is a wide-band(1-250 ke V) slat-collimator-based X-ray astronomy satellite with the capability of all-sky monitoring in 0.2-3 Me V. It was designed to perform pointing, scanning and gamma-ray burst(GRB)observations and, based on the Direct Demodulation Method (DDM), the image of the scanned sky region can be reconstructed.Here we give an overview of the mission and its progresses, including payload, core sciences, ground calibration/facility, ground segment, data archive, software, in-orbit performance, calibration, background model, observations and some preliminary results.展开更多
Conversational large language models(LLMs)such as ChatGPT and GPT-4 have recently exhibited remarkable capabilities across various domains,capturing widespread attention from the public.To facilitate this line of rese...Conversational large language models(LLMs)such as ChatGPT and GPT-4 have recently exhibited remarkable capabilities across various domains,capturing widespread attention from the public.To facilitate this line of research,in this paper,we report the development of MOSS,an open-sourced conversational LLM that contains 16 B parameters and can perform a variety of instructions in multi-turn interactions with humans.The base model of MOSS is pre-trained on large-scale unlabeled English,Chinese,and code data.To optimize the model for dialogue,we generate 1.1 M synthetic conversations based on user prompts collected through our earlier versions of the model API.We then perform preference-aware training on preference data annotated from AI feedback.Evaluation results on real-world use cases and academic benchmarks demonstrate the effectiveness of the proposed approaches.In addition,we present an effective practice to augment MOSS with several external tools.Through the development of MOSS,we have established a complete technical roadmap for large language models from pre-training,supervised fine-tuning to alignment,verifying the feasibility of chatGPT under resource-limited conditions and providing a reference for both the academic and industrial communities.Model weights and code are publicly available at https://github.com/OpenMOSS/MOSS.展开更多
In vivo fluorescence imaging in the second near-infrared window(NIR-II)has been considered as a promising technique for visualizing mammals.However,the definition of the NIR-II region and the mechanism accounting for ...In vivo fluorescence imaging in the second near-infrared window(NIR-II)has been considered as a promising technique for visualizing mammals.However,the definition of the NIR-II region and the mechanism accounting for the excellent performance still need to be perfected.Herein,we simulate the photon propagation in the NIR region(to 2340 nm),confirm the positive contribution of moderate light absorption by water in intravital imaging and perfect the NIR-II window as 900–1880 nm,where 1400–1500 and 1700–1880 nm are defined as NIR-IIx and NIR-IIc regions,respectively.Moreover,2080–2340 nm is newly proposed as the third near-infrared(NIR-III)window,which is believed to provide the best imaging quality.The wide-field fluorescence microscopy in the brain is performed around the NIRIIx region,with excellent optical sectioning strength and the largest imaging depth of intravital NIR-II fluorescence microscopy to date.We also propose 1400 nm long-pass detection in off-peak NIR-II imaging whose performance exceeds that of NIR-IIb imaging,using bright fluorophores with short emission wavelength.展开更多
We report a frequency-multiplexing method for multi-beam photon-counting light detection and ranging(Li DAR),where only one single-pixel single-photon detector is employed to simultaneously detect the multibeam echoes...We report a frequency-multiplexing method for multi-beam photon-counting light detection and ranging(Li DAR),where only one single-pixel single-photon detector is employed to simultaneously detect the multibeam echoes.In this frequency-multiplexing multi-beam Li DAR,each beam is from an independent laser source with different repetition rates and independent phases.As a result,the photon counts from different beams could be discriminated from each other due to the strong correlation between the laser pulses and their respective echo photons.A 16-beam Li DAR system was demonstrated in three-dimensional laser imaging with 16 pulsed laser diodes at 850 nm and one single-photon detector based on a Si-avalanche photodiode.This frequencymultiplexing method can greatly reduce the number of single-photon detectors in multi-beam Li DAR systems,which may be useful for low-cost and eye-safe Li DAR applications.展开更多
The effects of forced flows at different velocities on microstructure and solute distribution during the directional solidification of Sn-10 wt% Bi alloys under a simultaneous imposition of a transverse static magneti...The effects of forced flows at different velocities on microstructure and solute distribution during the directional solidification of Sn-10 wt% Bi alloys under a simultaneous imposition of a transverse static magnetic field(TSMF) and an external direct current(DC) have been investigated experimentally and numerically. The experimental results show that the solid-liquid interface will gradually become sloping with the increase of the forced flow velocity when the thermoelectric magnetic convection(TEMC)dominates the forced flow at solidification front. However, the interface will gradually become planar as the flow velocity further increases when the electromagnetic convection(EMC) dominates the forced flow. Moreover, when the flow velocity gradually increases, the primary dendrite spacing decreases from384 to 105 μm accordingly. The simulation results show that the solute distribution at the two sides of the sample can be significantly changed by the forced flow at solidification front. The rejected solute will be unidirectionally transported to one side of the sample along the TEMC(a low-velocity forced flow),thereby causing the formation of a sloping interface. However, the rejected solute will be returned back along the EMC(a higher-velocity force flow), which results in a planar interface. Furthermore, the solute content at the two sides of the sample under the forced flows at different velocities was measured. The results are in good agreement with the simulation results, which shows that the solute content difference between the two sides of the sample reaches the maximum when a 0.5 T TSMF is applied, while the solute content difference decreases to zero with a simultaneous application of a 0.5 T TSMF and a 1.6 × 10~5 A/m^2 external DC.展开更多
Photoelectrochemical(PEC) cells involved with semiconductor electrodes can simultaneously absorb solar energy and perform chemical reactions, which are considered as an attractive strategy to produce renewable and cle...Photoelectrochemical(PEC) cells involved with semiconductor electrodes can simultaneously absorb solar energy and perform chemical reactions, which are considered as an attractive strategy to produce renewable and clean hydrogen energy. Sb_(2)Se_(3) has been widely investigated in constructing PEC photocathodes benefitting of its low toxicity, suitable band gap, superior optoelectronic properties, and outstanding photocorrosion stability. We first present a brief overview of basic concepts and principles of PEC water splitting as well as a comparison between Sb_(2)Se_(3) and other numerous candidates. Then the material characteristics and preparation methods of Sb_(2)Se_(3) are introduced. The development of Sb_(2)Se_(3)-based photocathodes in PEC water splitting with various architectures and engineering efforts(i.e., absorber engineering, interfaces engineering, co-catalyst engineering and tandem engineering) to improve solar-to-hydrogen(STH) efficiency are highlighted. Finally, we debate the possible future directions to further explore the researching fields of Sb_(2)Se_(3)-based photocathodes with a strongly positive outlook in PEC processed solar hydrogen production.展开更多
Horizontal starch gel electrophoresis was used to investigate genetic structures of four populations (Dandong, Rizhao, Ningbo and Guangzhou) of redlip mullet (Chelon haematocheilus). Fourteen loci of ten enzymes (G3PD...Horizontal starch gel electrophoresis was used to investigate genetic structures of four populations (Dandong, Rizhao, Ningbo and Guangzhou) of redlip mullet (Chelon haematocheilus). Fourteen loci of ten enzymes (G3PDH, IDHP, LAP, LDH, MDH, MPI, PGDH, PGM, SDH, and SOD) were identified. The proportions of polymorphic loci varied from 0.07 to 0.14. The average observed and expected heterozygosities ranged from 0.02 to 0.05 and from 0.02 to 0.04 respectively among the 4 populations. The average number of efficient alleles of each locus varied from 1.02 to 1.06. The genetic distance among populations was from 0.0004 to 0.0021. The genetic distances between Dandong, Rizhao and Ningbo populations were small, while those between Guangzhou population and other three populations were relatively high. The result indicated the possible divergence of redlip mullet between the South China Sea and the other sea areas of China due to geographic isolation.展开更多
A new preparation method of near-net-shape 6.5 wt% Si high silicon steel sheets was proposed by combining composite electrodeposition(CED) and diffusion annealing under magnetic field. The obtained sheets were charact...A new preparation method of near-net-shape 6.5 wt% Si high silicon steel sheets was proposed by combining composite electrodeposition(CED) and diffusion annealing under magnetic field. The obtained sheets were characterized by scanning electron microscopy, energy dispersive spectrometry, analytical balance and a silicon steel material measurement system. The results show that the surface morphology,the elemental distribution, the cathode current efficiency and the silicon content of coatings were obviously influenced by the micro and macro magnetohydrodynamics(MHD) flows under magnetic field.With the effect of magnetic field, the silicon particles content of coatings showed an increasing trend and the diffusion process showed that an approximately uniform 6.5 wt% silicon steel sheet has been successfully obtained. The magnetism measurement showed that the high silicon steel sheet has the lower iron loss, and the iron loss further decreased under magnetic field. The new method proposed in this article,which is more environmentally friendly and low energy consumption, is feasible to prepare high silicon steel sheets.展开更多
基金supported by the National Program on Key Research and Development Project(Grant No.2016YFA0400800)from the Ministry of Science and Technology of China(MOST)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB23040400)the Hundred Talent Program of Chinese Academy of Sciences,the National Natural Science Foundation of China(Grant Nos.11233001,11503027,11403026,11473027,and11733009)
文摘Finding the electromagnetic （EM） counterpart of binary compact star merger, especially the binary neutron star （BNS） merger, is critically important for gravitational wave （GW） astronomy, cosmology and fundamental physics. On Aug. 17, 2017, Advanced LIGO and Fermi/GBM independently triggered the first BNS merger, GW170817, and its high energy EM counterpart, GRB 170817A, respectively, resulting in a global observation campaign covering gamma-ray, X-ray, UV, optical, IR, radio as well as neutrinos. The High Energy X-ray telescope （HE） onboard Insight-HXMT （Hard X-ray Modulation Telescope） is the unique high-energy gamma-ray telescope that monitored the entire GW localization area and especially the optical counterpart （SSS17a/AT2017gfo） with very large collection area （M000 cm2） and microsecond time resolution in 0.2-5 MeV. In addition, Insight-HXMT quickly implemented a Target of Opportunity （TOO） observation to scan the GW localization area for potential X-ray emission from the GW source. Although Insight-HXMT did not detect any significant high energy （0.2-5 MeV） radiation from GW170817, its observation helped to confirm the unexpected weak and soft nature of GRB 170817A. Meanwhile, Insight-HXMT/HE provides one of the most stringent constraints （-10-7 to 104 erg/cm2/s） for both GRB170817A and any other possible precursor or extended emissions in 0.2-5 MeV, which help us to better understand the properties of EM radiation from this BNS merger. Therefore the observation of Insight-HXMT constitutes an important chapter in the full context of multi-wavelength and multi-messenger observation of this historical GW event.
基金support of the Chinese Academy of Sciences through the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDA15020100)support by ASI, under the dedicated eXTP agreements and agreement ASI-INAF (Grant No. 2017-14-H.O.)+3 种基金by INAF and INFN under project REDSOXsupport from the Deutsche Zentrum für Luft- und Raumfahrt, the German Aerospce Center (DLR)support of Science Centre (Grant No. 2013/10/M/ST9/00729)support from MINECO (Grant No. ESP2017-82674-R) and FEDER funds
文摘In this paper we present the enhanced X-ray Timing and Polarimetry mission—eXTP. eXTP is a space science mission designed to study fundamental physics under extreme conditions of density, gravity and magnetism. The mission aims at determining the equation of state of matter at supra-nuclear density, measuring effects of QED, and understanding the dynamics of matter in strong-field gravity. In addition to investigating fundamental physics, eXTP will be a very powerful observatory for astrophysics that will provide observations of unprecedented quality on a variety of galactic and extragalactic objects. In particular, its wide field monitoring capabilities will be highly instrumental to detect the electro-magnetic counterparts of gravitational wave sources.The paper provides a detailed description of:(1) the technological and technical aspects, and the expected performance of the instruments of the scientific payload;(2) the elements and functions of the mission, from the spacecraft to the ground segment.
基金project funded by China National Space Administration(CNSA)and the Chinese Academy of Sciences(CAS)support from the National Key Research and Development Program of China(Grant No.2016YFA0400800)+1 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant Nos.XDA04010202,XDA04010300,and XDB23040400)the National Natural Science Foundation of China(Grant Nos.U1838201,and U1838102).
文摘As China’s first X-ray astronomical satellite, the Hard X-ray Modulation Telescope (HXMT), which was dubbed as Insight-HXMT after the launch on June 15, 2017, is a wide-band(1-250 ke V) slat-collimator-based X-ray astronomy satellite with the capability of all-sky monitoring in 0.2-3 Me V. It was designed to perform pointing, scanning and gamma-ray burst(GRB)observations and, based on the Direct Demodulation Method (DDM), the image of the scanned sky region can be reconstructed.Here we give an overview of the mission and its progresses, including payload, core sciences, ground calibration/facility, ground segment, data archive, software, in-orbit performance, calibration, background model, observations and some preliminary results.
基金supported by the National Natural Science Foundation of China(No.62022027).
文摘Conversational large language models(LLMs)such as ChatGPT and GPT-4 have recently exhibited remarkable capabilities across various domains,capturing widespread attention from the public.To facilitate this line of research,in this paper,we report the development of MOSS,an open-sourced conversational LLM that contains 16 B parameters and can perform a variety of instructions in multi-turn interactions with humans.The base model of MOSS is pre-trained on large-scale unlabeled English,Chinese,and code data.To optimize the model for dialogue,we generate 1.1 M synthetic conversations based on user prompts collected through our earlier versions of the model API.We then perform preference-aware training on preference data annotated from AI feedback.Evaluation results on real-world use cases and academic benchmarks demonstrate the effectiveness of the proposed approaches.In addition,we present an effective practice to augment MOSS with several external tools.Through the development of MOSS,we have established a complete technical roadmap for large language models from pre-training,supervised fine-tuning to alignment,verifying the feasibility of chatGPT under resource-limited conditions and providing a reference for both the academic and industrial communities.Model weights and code are publicly available at https://github.com/OpenMOSS/MOSS.
基金This work was supported by the National Natural Science Foundation of China(61975172,82001874,and 21974104)Fundamental Research Funds for the Central Universities(2020-KYY-511108-0007)Natural Science Foundation of Zhejiang Province(LR17F050001).
文摘In vivo fluorescence imaging in the second near-infrared window(NIR-II)has been considered as a promising technique for visualizing mammals.However,the definition of the NIR-II region and the mechanism accounting for the excellent performance still need to be perfected.Herein,we simulate the photon propagation in the NIR region(to 2340 nm),confirm the positive contribution of moderate light absorption by water in intravital imaging and perfect the NIR-II window as 900–1880 nm,where 1400–1500 and 1700–1880 nm are defined as NIR-IIx and NIR-IIc regions,respectively.Moreover,2080–2340 nm is newly proposed as the third near-infrared(NIR-III)window,which is believed to provide the best imaging quality.The wide-field fluorescence microscopy in the brain is performed around the NIRIIx region,with excellent optical sectioning strength and the largest imaging depth of intravital NIR-II fluorescence microscopy to date.We also propose 1400 nm long-pass detection in off-peak NIR-II imaging whose performance exceeds that of NIR-IIb imaging,using bright fluorophores with short emission wavelength.
基金National Natural Science Foundation of China(11621404,11774095,11804099)Shanghai Basic Research Project(18JC1412200)Program of Introducing Talents of Discipline to Universities(B12024)
文摘We report a frequency-multiplexing method for multi-beam photon-counting light detection and ranging(Li DAR),where only one single-pixel single-photon detector is employed to simultaneously detect the multibeam echoes.In this frequency-multiplexing multi-beam Li DAR,each beam is from an independent laser source with different repetition rates and independent phases.As a result,the photon counts from different beams could be discriminated from each other due to the strong correlation between the laser pulses and their respective echo photons.A 16-beam Li DAR system was demonstrated in three-dimensional laser imaging with 16 pulsed laser diodes at 850 nm and one single-photon detector based on a Si-avalanche photodiode.This frequencymultiplexing method can greatly reduce the number of single-photon detectors in multi-beam Li DAR systems,which may be useful for low-cost and eye-safe Li DAR applications.
基金financially supported by the National Key Research and Development Program of China (No.2016YFB0301401)the National Natural Science Foundation of China (No.U1732276)+1 种基金the Science and Technology Commission of Shanghai Municipality (Key Project Nos.13JC1402500 and 15520711000)the Independent Research and Development Project of State Key of Advanced Special Steel,Shanghai University (Nos.SKLASS2015-Z021 and SELF-2014-02)
文摘The effects of forced flows at different velocities on microstructure and solute distribution during the directional solidification of Sn-10 wt% Bi alloys under a simultaneous imposition of a transverse static magnetic field(TSMF) and an external direct current(DC) have been investigated experimentally and numerically. The experimental results show that the solid-liquid interface will gradually become sloping with the increase of the forced flow velocity when the thermoelectric magnetic convection(TEMC)dominates the forced flow at solidification front. However, the interface will gradually become planar as the flow velocity further increases when the electromagnetic convection(EMC) dominates the forced flow. Moreover, when the flow velocity gradually increases, the primary dendrite spacing decreases from384 to 105 μm accordingly. The simulation results show that the solute distribution at the two sides of the sample can be significantly changed by the forced flow at solidification front. The rejected solute will be unidirectionally transported to one side of the sample along the TEMC(a low-velocity forced flow),thereby causing the formation of a sloping interface. However, the rejected solute will be returned back along the EMC(a higher-velocity force flow), which results in a planar interface. Furthermore, the solute content at the two sides of the sample under the forced flows at different velocities was measured. The results are in good agreement with the simulation results, which shows that the solute content difference between the two sides of the sample reaches the maximum when a 0.5 T TSMF is applied, while the solute content difference decreases to zero with a simultaneous application of a 0.5 T TSMF and a 1.6 × 10~5 A/m^2 external DC.
基金supported by the National Natural Science Foundation of China(No.62074102)Natural Science Foundation of Guangdong Province(2020A1515010805)China+1 种基金the Key Project of Department of Education of Guangdong Province(No.2018KZDXM059)Chinathe Science and Technology plan project of Shenzhen(20200812000347001,JCYJ20190808153409238)China。
文摘Photoelectrochemical(PEC) cells involved with semiconductor electrodes can simultaneously absorb solar energy and perform chemical reactions, which are considered as an attractive strategy to produce renewable and clean hydrogen energy. Sb_(2)Se_(3) has been widely investigated in constructing PEC photocathodes benefitting of its low toxicity, suitable band gap, superior optoelectronic properties, and outstanding photocorrosion stability. We first present a brief overview of basic concepts and principles of PEC water splitting as well as a comparison between Sb_(2)Se_(3) and other numerous candidates. Then the material characteristics and preparation methods of Sb_(2)Se_(3) are introduced. The development of Sb_(2)Se_(3)-based photocathodes in PEC water splitting with various architectures and engineering efforts(i.e., absorber engineering, interfaces engineering, co-catalyst engineering and tandem engineering) to improve solar-to-hydrogen(STH) efficiency are highlighted. Finally, we debate the possible future directions to further explore the researching fields of Sb_(2)Se_(3)-based photocathodes with a strongly positive outlook in PEC processed solar hydrogen production.
文摘Horizontal starch gel electrophoresis was used to investigate genetic structures of four populations (Dandong, Rizhao, Ningbo and Guangzhou) of redlip mullet (Chelon haematocheilus). Fourteen loci of ten enzymes (G3PDH, IDHP, LAP, LDH, MDH, MPI, PGDH, PGM, SDH, and SOD) were identified. The proportions of polymorphic loci varied from 0.07 to 0.14. The average observed and expected heterozygosities ranged from 0.02 to 0.05 and from 0.02 to 0.04 respectively among the 4 populations. The average number of efficient alleles of each locus varied from 1.02 to 1.06. The genetic distance among populations was from 0.0004 to 0.0021. The genetic distances between Dandong, Rizhao and Ningbo populations were small, while those between Guangzhou population and other three populations were relatively high. The result indicated the possible divergence of redlip mullet between the South China Sea and the other sea areas of China due to geographic isolation.
基金financial support of the National Key Research and Development Program of China(No.2016YFB0300401)the Science and Technology Commission of Shanghai Municipality(Key Project No.13JC1402500,15520711000)the Independent Research and Development Project of State Key of Advanced Special Steel,Shanghai University(Nos.SKLASS2015-Z021 and SELF-2014-02)
文摘A new preparation method of near-net-shape 6.5 wt% Si high silicon steel sheets was proposed by combining composite electrodeposition(CED) and diffusion annealing under magnetic field. The obtained sheets were characterized by scanning electron microscopy, energy dispersive spectrometry, analytical balance and a silicon steel material measurement system. The results show that the surface morphology,the elemental distribution, the cathode current efficiency and the silicon content of coatings were obviously influenced by the micro and macro magnetohydrodynamics(MHD) flows under magnetic field.With the effect of magnetic field, the silicon particles content of coatings showed an increasing trend and the diffusion process showed that an approximately uniform 6.5 wt% silicon steel sheet has been successfully obtained. The magnetism measurement showed that the high silicon steel sheet has the lower iron loss, and the iron loss further decreased under magnetic field. The new method proposed in this article,which is more environmentally friendly and low energy consumption, is feasible to prepare high silicon steel sheets.
