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New Vacuum Solar Telescope Achieves Narrowband Infrared Solar Imaging Observation at He I 10830 A

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Research in Astronomy and Astrophysics 2024年第5期24卷 76-84页

作者： Wei-Jie Meng Fang-yu Xu Zhen-yu Jin yunnan Observatories Chinese Academy of SciencesKunming 650011China yunnan Key Laboratory of Solar Physics and Space Science Kunming 650216China University of Chinese Academy of Sciences Beijing 100049China

The near-infrared imaging channel constitutes a crucial component of the multichannel high-resolution imaging system of the New Vacuum Solar Telescope(NVST). We have successfully achieved high-resolution, narrowband imaging of the chromosphere using He I 10830 A triplet within this channel, which significantly enhances the imaging observation capabilities of NVST. This paper provides a concise overview of the optical system associated with the near-infrared imaging channel, detailing data processing procedures and presenting several observed images. Leveraging a high-resolution image reconstruction algorithm, we were able to generate a narrowband image near the diffraction limit at 10830 A with a temporal resolution of less than 10 s.

关键词： instrumentation detectors-instrumentation high angular resolution-Sun chromosphere-Sun infrared

Dual-objective two-photon microscope for volumetric imaging of dense scattering biological samples by bidirectional excitation and collection

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Photonics Research 2024年第6期12卷 1351-1361页

作者： MUyuE ZHAI JING yu YANHUI HU HANG yu bEICHEN XIE YI yu DAWEI LI AIMIN WANG HEPING CHENG National biomedical Imaging Center College of Future TechnologyPeking UniversityBeijing 100871China Research Unit of Mitochondria in brain Diseases Chinese Academy of Medical SciencesPKU-Nanjing Institute of Translational MedicineNanjing 211500China beijing Transcend Vivoscope biotech Beijing 100085China College of Engineering Peking UniversityBeijing 100871China Academy for Advanced Interdisciplinary Studies Peking UniversityBeijing 100871China Center for Quantitative biology Peking UniversityBeijing 100871China School of Electronics Peking UniversityBeijing 100871China State Key Laboratory of Advanced Optical Communication System and Networks Peking UniversityBeijing 100871China

Full view observation throughout entire specimens over a prolonged period is crucial when exploring the physiological functions and system-level ***-photon microscopy(MPM)has been widely employed for such purposes owing to its deep penetration ***,the current MPM struggles with balancing the imaging depth and quality while avoiding photodamage for the exponential increasement of excitation power with the imaging ***,we present a dual-objective two-photon microscope(Duo-2P),characterized by bidirectional two-photon excitation and fluorescence collection,for long-duration volumetric imaging of dense scattering ***-2P effectively doubles the imaging depth,reduces the total excitation energy by an order of magnitude for samples with a thickness five times the scattering length,and enhances the signal-to-noise ratio up to 1.4 *** these advantages,we acquired volumetric images of a 380-μm suprachiasmatic nucleus slice for continuous 4-h recording at a rate of 1.67 s/volume,visualized the calcium activities over 4000 neurons,and uncovered their state-switching *** conclude that Duo-2P provides an elegant and powerful means to overcome the fundamental depth limit while mitigating photodamages for deep tissue volumetric imaging.

关键词： excitation overcome exponential

New speckle pattern interferometry for precise in situ deformation measurements

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Chinese Optics Letters 2024年第1期22卷 34-40页

作者：章如月 yu Fu 缪泓 CAS Key Laboratory of Mechanical behavior and Design of Materials Department of Modern MechanicsUniversity of Science and Technology of ChinaHefei 230027China Shenzhen Key Laboratory of Intelligent Optical Measurement and Detection College of Physics and Optoelectronic EngineeringShenzhen UniversityShenzhen 518060China

A new electronic speckle pattern interferometry method is proposed to realize in situ deformation *** feature of the method is the combination of a high-speed camera and multiple laser Doppler vibrometers(LDVs)for synchronous *** high-speed camera is used to record and select effective interferograms,while the LDVs are used to measure the rigid body displacement caused by vibrations.A series of effective interferograms with known shifted phase values are obtained to calculate the deformation *** experimental results show that the method performs well in measuring static and dynamic deformations with high accuracy in vibrating environments.

关键词： speckle pattern interferometry laser Doppler vibrometers in situ deformation measurements

Numerical simulations of Atlantic meridional overturning circulation(AMOC)from OMIP experiments and its sensitivity to surface forcing

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Journal of Oceanology and Limnology 2024年第2期42卷 454-467页

作者： Xiaowei WANG Yongqiang yu State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics(LASG) Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China University of Chinese Academy of Sciences Beijing 100049China

Atlantic meridional overturning circulation(AMOC)plays an important role in transporting heat meridionally in the Earth’s climate system and is also a key metrical tool to verify oceanic general circulation *** OMIP(Ocean Model Intercomparison Project phase 1 and 2)simulations with LICOM3(version 3 of the LASG/IAP Climate System Ocean Model)developed at the State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics(LASG),Institute of Atmospheric Physics(IAP),are compared in this *** simulations well reproduce the fundamental characteristics of the AMOC,but the OMIP1 simulation shows a significantly stronger AMOC than the OMIP2 *** the LICOM3 configurations are identical between these two experiments,any differences between them must be attributed to the surface forcing *** analysis suggests that sea surface salinity(SSS)differences should be mainly responsible for the enhanced AMOC in the OMIP1 simulation,but sea surface temperature(SST)also play an unignorable role in modulating *** the North Atlantic,where deep convection occurs,the SSS in OMIP1 is more saline than that in *** find that in the major region of deep convection,the change of SSS has more significant effect on density than the change of *** a result,the SSS was more saline than that in OMIP2,leading to stronger deep convection and subsequently intensify the *** conduct a series of numerical experiments with LICOM3,and the results confirmed that the changes in SSS have more significant effect on the strength of AMOC than the changes in SST.

关键词： oceanic general circulation model(OGCM) Atlantic meridional overturning(AMOC) surface forcing deep convection

The Logarithmic Sobolev Inequality for a Submanifold in Manifolds with Nonnegative Sectional Curvature

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Chinese Annals of Mathematics,Series b 2024年第3期45卷 487-496页

作者： Chengyang YI yu ZHENG School of Mathematical Sciences East China Normal UniversityShanghai 200241China

The authors prove a sharp logarithmic Sobolev inequality which holds for compact submanifolds without boundary in Riemannian manifolds with nonnegative sectional curvature of arbitrary dimension and *** the Michael-Simon Sobolev inequality,this inequality includes a term involving the mean *** extends a recent result of brendle with Euclidean setting.

关键词： Logarithmic Sobolev inequality Nonnegative sectional curvature Submanifold

State-of-the-art on the anchorage performance of rock bolts subjected to shear load

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International Journal of Coal Science & Technology 2024年第1期11卷 1-30页

作者： yu Chen Haodong Xiao School of Civil Engineering Sun Yat-sen UniversityZhuhai519082China

Rock bolts are extensively utilized in underground engineering as a means of offering support and stability to rock masses in tunnels,mines,and other underground *** environments of high ground stress,faults or weak zones can frequently arise in rock formations,presenting a significant challenge for engineering and potentially leading to underground engineering *** bolts serve as a crucial structural element for the transmission of tensile stress and are capable of withstanding shear loads to prevent sliding of weak zones within rock ***,a complete understanding of the behavior of rock bolts subjected to shear loads is *** paper presents a state-of-the-art review of the research progress of rock bolts subjected to shear load in three categories:experiment,numerical simulation,and analytical *** review focuses on the research studies and developments in this area since the 1970s,providing a comprehensive overview of numerous factors that influence the anchorage performance of rock *** factors include the diameter and angle of the rock bolt installation,rock strength,grouting material,bolt material,borehole diameter,rock bolt preload,normal stress,joint surface roughness and joint expansion *** paper reviews the improvement of mechanical parameter setting in numerical simulation of rock bolt ***,it delves into the optimization of the analytical model concerning rock bolt shear theory,approached from the perspectives of both Elastic foundation beam theory coupled with Elastoplasticity theory and Structural mechanic *** significance of this review lies in its ability to provide insights into the mechanical behavior of rock *** paper also highlights the limitations of current research and guidelines for further research of rock bolts.

关键词： Rock bolt Shear load Shear test Numerical simulation Analytical model

Global precipitation change during the Holocene:a combination of records and simulations

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Frontiers of Earth Science 2024年第1期18卷 112-126页

作者： Wangting YE yu LI Key Laboratory of Western China᾽s Environmental Systems(Ministry of Education) College of Earth and Environmental SciencesCenter for Hydrologic Cycle and Water Resources in Arid RegionLanzhou UniversityLanzhou 730000China

Precipitation can shape our climate both in the present and the *** though we have made significant advances in studying the mechanisms of millennial-scale climate changes through high-resolution records,we still cannot quantitatively characterize the global spatiotemporal precipitation variations within the ***,we developed a new approach to integrating data from 349 globally distributed records and climate models to reconstruct regional and global precipitation patterns over the last 12000 *** results reveal that precipitation reconstructions can be divided into monsoon-driven and westerly driven *** results suggest that an arid climate was experienced in the late glacial and early Holocene epoch(~12−7.4 cal ka bP),attaining a middle Holocene optimum(~7.4−3.5 cal ka bP),and drier after the middle *** to our reconstructions,the global precipitation reconstruction increased from the early Holocene until 3.8 cal ka bP and then subsequently *** addition,our reconstructions better reproduce the low-frequency events and extreme precipitation at the millennial scale in the hemispheres,but the performance of the reconstructions in the equatorial Pacific and the Southern Hemisphere of Africa and the Americas is *** resolution of the record and the simulation capability of the climate model remain important means to improve our understanding of past climate change.

关键词： Holocene equatorial glacial

Nonsolvable Groups with Three Nonlinear Irreducible Character Codegrees

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Chinese Annals of Mathematics,Series b 2024年第2期45卷 173-178页

作者： Dongfang YANG yu ZENG Department of Mathematics Changshu Institute of TechnologyChangshu 215500JiangsuChina

For an irreducible characterχof a?nite group G,the codegree ofχis de-?ned as|G:ker(χ)|/χ(1).In this paper,the authors determine?nite nonsolvable groups with exactly three nonlinear irreducible character codegrees,... 详细信息

关键词： Character codegree Nonsolvable group

Persistent Variations in the East Asian Trough from March to April and the Possible Mechanism

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Advances in Atmospheric Sciences 2024年第4期41卷 737-753,I0002-I0004页

作者： Shui yu Jianqi SUN Nansen-Zhu International Research Center Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China College of Earth and Planetary Sciences University of Chinese Academy of SciencesBeijing 100049China

The East Asian trough(EAT)profoundly influences the East Asian spring *** this study,the relationship of the EATs among the three spring months is *** analysis shows that the variation in March EAT is closely related to that of April *** empirical orthogonal function(EEOF)analysis also confirms the co-variation of the March and April *** positive/negative EEOF1 features the persistent strengthened/weakened EAT from March to *** investigation indicates that the variations in EEOF1 are related to a dipole sea surface temperature(SST)pattern over the North Atlantic and the SST anomaly over the tropical Indian *** dipole SST pattern over the North Atlantic,with one center east of Newfoundland Island and another east of bermuda,could trigger a Rossby wave train to influence the EAT in March−*** SST anomaly over the tropical Indian Ocean can change the Walker circulation and influence the atmospheric circulation over the tropical western Pacific,subsequently impacting the southern part of the EAT in March−*** the SST factors,the Northeast Asian snow cover could change the regional thermal conditions and lead to persistent EAT anomalies from March to *** three impact factors are generally independent of each other,jointly explaining large variations in the EAT ***,the signals of the three factors could be traced back to February,consequently providing a potential prediction source for the EAT variation in March and April.

关键词： spring East Asian trough sea surface temperature snow cover