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Optical system for extremely large spectroscopic survey telescope

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Science China(Physics,Mecha.ics & Astronomy) 2024年第7期67卷 158-174页

作者： ding-qiang Su Hua Bai Xiangyan Yuan Xiangqun Cui Key Laboratory of the Ministry of Education School of Astronomy and Space ScienceNanjing UniversityNanjing 210023China Nanjing Institute of Astronomical Optics and Technology(NIAOT) Chinese Academy of SciencesNanjing 210042China University of Chinese Academy of Sciences Nanjing 211135China School of Astronomy and Space Science University of Chinese Academy of SciencesBeijing 101408China

This article presents research work on a spectroscopic survey *** idea is as follows:for such a telescope,a pure reflecting optical system is designed,which should ha.e an aperture and a field of view(FOV)both as large as possible and excellent image quality,and then a strip lensm(lens-prism)atmospheric dispersion corrector(S-ADC)is added,only for correcting the atmospheric *** the fund limitation and the simplicity of scaling up,some 12-m telescopes are designed as ***,Korsch,and Meinel put forward the four-mirror Nasmyth systems I and II,which are used in this *** of 1.5°,2°,and 2.5°are *** all systems,the image qualities are *** the S-ADC relaxes the optical glass size restriction,this 12-m telescope with a FOV of 2.5°can be magnified in proportion to a 16-m *** etendue(from Frenchétendue)and focal surface will now be the largest in the *** such a telescope,a pure reflecting optical system can also be obtained.A subsequent coudésystem is designed with excellent image quality.

关键词： telescopes spectroscopic survey

Compliance motion control of the hydraulic dual-arm manipulator with adaptive mass estimation of unknown object

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Frontiers of Mecha.ical Engineering 2024年第1期19卷 35-52页

作者： Bolin SUN Min CHENG Ruqi ding Bing XU State Key Laboratory of Mecha.ical Transmissions Chongqing UniversityChongqing 400044China Key Laboratory of Conveyance and Equipment(Ministry of Education) East China Jiaotong UniversityNanchang 330013China State Key Laboratory of Fluid Power and Mecha.ronic Systems Zhejiang UniversityHangzhou 310027China

Given the limited operating ability of a single robotic arm,dual-arm collaborative operations ha.e become increasingly *** with the electrically driven dual-arm manipulator,due to the unknown heavy load,difficulty in measuring contact forces,and control complexity during the closed-cha.n object transportation task,the hydraulic dual-arm manipulator(HDM)faces more difficulty in accurately tracking the desired motion trajectory,which may cause object deformation or even *** overcome this problem,a compliance motion control method is proposed in this paper for the *** mass parameter of the unknown object is obtained by using an adaptive method based on velocity *** to the difficulty in obtaining the actual internal force of the object,the pressure signal from the pressure sensor of the hydraulic system is used to estimate the contact force at the end-effector(EE)of two hydraulic manipulators(HMs).Further,the estimated contact force is used to calculate the actual internal force on the ***,a compliance motion controller is designed for HDM closed-cha.n *** position and internal force errors of the object are reduced by the feedback of the position,velocity,and internal force errors of the object to achieve the effect of the compliance motion of the HDM,i.e.,to reduce the motion error and internal force of the *** required velocity and force at the EE of the two HMs,including the position and internal force errors of the object,are inputted into separate position *** addition,the position controllers of the two individual HMs are designed to enable precise motion control by using the virtual decomposition control ***,comparative experiments are carried out on a hydraulic dual-arm test *** proposed method is validated by the experimental results,which demonstrate improved object position accuracy and reduced internal force.

关键词： hydraulic dual-arm manipulator compliance motion control unknown object adaptive mass estimation nonlinear control

Distributed Fault Estimation for Nonlinear Systems With Sensor Saturation and Deception Attacks Using Stocha.tic Communication Protocols

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IEEE/CAA Journal of Automatica Sinica 2024年第8期11卷 1865-1876页

作者： Weiwei Sun Xinci Gao Lusong ding Xiangyu Chen Institute of Automation Qufu Normal UniversityQufu 273165China

This paper is aimed at the distributed fault estimation issue associated with the potential loss of actuator efficiency for a type of discrete-time nonlinear systems with sensor *** the distributed estimation structure under consideration,an estimation center is not necessary,and the estimator derives its information from itself and neighboring nodes,which fuses the state vector and the measurement *** an effort to cut down data conflicts in communication networks,the stocha.tic communication protocol(SCP)is employed so tha. the output signals from sensors can be ***,a recursive security estimator scheme is created since attackers randomly inject malicious signals into the selected *** this basis,sufficient conditions for a fault estimator with less conservatism are presented which ensure an upper bound of the estimation error covariance and the mean-square exponential boundedness of the estimating ***,a numerical example is used to show the reliability and effectiveness of the considered distributed estimation algorithm.

关键词： Actuator fault deception attacks distributed estimation sensor saturation stocha.tic communication protocol(SCP).

A review on g-C_(3)N_(4)decorated with silver for photocatalytic energy conversion

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Chinese Chemical Letters 2024年第2期35卷 187-196页

作者： Ziyu Pan Wufan ding ha.chun Chen ha.dong Ji Eco-environment and Resource Efficiency Research Laboratory School of Environment and EnergyPeking University Shenzhen Graduate SchoolShenzhen 518055China

Artificial photocatalytic energy conversion is considered as the most potential strategy for solving the increasingly serious energy crisis and environmental pollution problems by directly capturing solar ***,high efficiency photocatalyst ha. drawn significant research attention in recent *** to the excellent electronic,optical,structural,and physicochemical performances,silver-based g-C_(3)N_(4)ha.e become promising *** review empha.izes the recent progresses and cha.lenges on g-C_(3)N_(4)decorated with silver for photocatalytic energy *** extensive use of g-C_(3)N_(4)decorated with silver in diverse photocatalytic reactions,including hydrogen evolution,pollutant degradation and carbon dioxide reduction,is also fully *** addition,we propose the perspectives of g-C_(3)N_(4)decorated with silver on photocatalytic *** hope tha. this review will shed some light on the photocatalytic energy conversion of g-C_(3)N_(4)decorated with silver.

关键词： g-C_(3)N_(4) Silver-modified g-C_(3)N_(4) Photocatalytic energy conversion H_(2)evolution Pollutant degradation CO_(2)reduction

Development of porphyrin-based fluorescent sensors and sensor arrays for saccha.ide recognition

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Chinese Chemical Letters 2024年第2期35卷 16-23页

作者： Yubin ding Jiaxin Wang Ruinan Wang Yongshu Xie Department of Chemistry College of SciencesNanjing Agricultural UniversityNanjing 210095China Sha.gha. Key Laboratory of Functional Materials Chemistry Key Laboratory for Advanced Materials and Institute of Fine ChemicalsSchool of Chemistry and Molecular EngineeringEast China University of Science & TechnologyShanghai 200237China

Saccha.ide sensing is a very meaningful research topic as saccha.ides are involved in many biological ***,it is cha.lenging to design molecular sensors for saccha.ides because this family of compounds is hydromimetic in aqueous solutions and sha.es a similar chemical *** this review,research progress in the development of porphyrin-based saccha.ide sensors is described with representative *** focus on using porphyrin as the signal reporter because porphyrins exhibit unique advantages in high chemical stability,long emission wavelength,and multiple structural modification *** literature results ha.e been classified into mainly two sections according to the general working principles of the porphyrin sensor *** the first section,recognition unit,design strategy and sensing performance of traditional porphyrin-based selective saccha.ide sensors are *** in the second section,development of porphyrin-based sensor arrays for pattern recognition of saccha.ides ha. been *** through the design strategy and sensing performance of reported achievements,it is reasonable to anticipate a bright future for designing practical porphyrin-based saccha.ide sensors.

关键词： Porphyrin Saccha.ide Fluorescent sensing Selective sensing Pattern recognition

Numerical analysis of geosynthetic-reinforced embankment performance under moving loads

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Journal of Rock Mecha.ics and Geotechnical Engineering 2024年第2期16卷 682-696页

作者： Xuanming ding Jinqiao Zha. Qiang Ou Jianfei Liu College of Civil Engineering Chongqing UniversityChongqing400045China Key Laboratory of New Technology for Construction of Cities in Mountain Area Chongqing UniversityChongqing400045China China United Engineering Corporation Limited Hangzhou310052China

The performance of geosynthetic-reinforced embankments under traffic moving loads is always a hotspot in the geotechnical engineering field.A three-dimensional(3D)model of a geosynthetic-reinforced embankment without drainage consolidation was established using the finite element software *** this model,the traffic loads were simulated by two moving loads of rectangular pattern,and their amplitude,range,and moving speed were realized by a Fortran *** embankment fill was simulated by an equivalent linear viscoelastic model,which can reflect its *** geogrid was simulated by the truss element,and the geocell was simulated by the membrane *** elements were utilized to weaken the boundary effect caused by the model geometry at the *** of the established numerical model was conducted by comparing the predicted deformations in the cross-section of the geosynthetic-reinforced embankment with those from the existing *** this basis,the dynamic stress and strain distribution in the pavement structure layer of the geosynthetic-reinforced embankment under a moving load was also ***,a parametric study was conducted to examine the influences of the different types of reinforcement,overload,and the moving load velocity on the geosynthetic-reinforced embankment.

关键词： Geosynthetic-reinforced layer Numerical model Moving load Embankment Deformation Stress

Effect of hot isostatic pressure on the microstructure and tensile properties of γ'-strengthened superalloy fabricated through induction-assisted directed energy deposition

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International Journal of Minerals,Metallurgy and Materials 2024年第5期31卷 1089-1097页

作者： Jianjun Xu ha.lin ding Xin Lin Feng Liu Analytical&Testing Center Northwestern Polytechnical UniversityXi’an 710072China State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi’an 710072China

The microstructure cha.acteristics and strengthening mecha.ism of Inconel738LC(IN-738LC) alloy prepared by using induction-assisted directed energy deposition(IDED) were elucidated through the investigation of samples subjected to IDED under 1050℃ preheating with and without hot isostatic pressing(HIP,1190℃,105 MPa,and 3 h).Results show tha. the as-deposited sample mainly consisted of epitaxial columnar crystals and inhomogeneously distributed γ’ pha.es in interdendritic and dendritic core *** HIP,grain morphology cha.ged negligibly,whereas the size of the γ’ pha.e became increasingly *** further heat treatment(HT,1070℃,2 h + 845℃,24 h),the γ’ pha.e in the as-deposited and HIPed samples presented a bimodal size distribution,whereas tha. in the as-deposited sample showed a size tha. remained *** comparison of tensile properties revealed tha. the tensile strength and uniform elongation of the HIP + HTed sample increased by 5% and 46%,respectively,due to the synergistic deformation of bimodal γ’pha.es,especially large cubic γ’ ***,the relationship between pha.e transformations and plastic deformations in the IDEDed sample was discussed on the basis of generalized stability theory in terms of the trade-off between thermodynamics and kinetics.

关键词： directed energy deposition Ni-based superalloys high-temperature preheating hot isostatic pressing microstructure tensile properties

Long way up:rethink diseases in light of pha.e separattion and pha.e transition

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Protein & Cell 2024年第7期15卷 475-492页

作者： Mingrui ding Weifan Xu Gaofeng Pei Pilong Li State Key Laboratory of Membrane Biology&Frontier Research Center for Biological Structure School of Life SciencesTsinghua UniversityBeijing 100084China Tsinghua-Peking Center for Life Sciences Beijing 100084China NuPha.e Therapeutics Beijing 100083China

Biomolecular condensation, driven by multivalency, serves as a fundamental mecha.ism within cells, facilitating the formation of distinct compartments, including membraneless organelles tha. play essential roles in various cellular processes. Perturbations in the delicate equilibrium of condensation, whether resulting in gain or loss of pha.e separation, ha.e robustly been associated with cellular dysfunction and physiological disorders. As ongoing research endeavors wholeheartedly embrace this newly acknowledged principle, a transformative shift is occurring in our comprehension of disease. Consequently, significant strides ha.e been made in unraveling the profound relevance and potential causal connections between abnormal pha.e separation and various diseases. This comprehensive review presents compelling recent evidence tha. highlight the intricate associations between aberrant pha.e separation and neurodegenerative diseases, cancers, and infectious diseases. Additionally, we provide a succinct summary of current efforts and propose innovative solutions for the development of potential therapeutics to combat the pathological consequences attributed to aberrant pha.e separation.

关键词： multivalency compartments aberant pha.e separation therapeutics gain or loss of pha.e separation diseases

A new mixed type crack propagation criterion in sha.e reservoirs

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Petroleum 2024年第1期10卷 85-92页

作者： Muru ding Zhirong Jin Yanjun Zha.g Jinghong Hu Beijing Key Laboratory of Unconventional Natural Gas Geology Evaluation and Development Engineering China University of Geosciences Sinopec Jiangsu Oil Field Branch Oil & Gas Technology Research Institute Changqing Oilefiled CompanyPetroChina

Hydraulic fracturing is a mainstream technology for unconventional oil and gas reservoirs development all over the world. How to use this technology to achieve high-level oil and gas resource extraction and how to form complex fracture networks as hydrocarbon transportation cha.nels in tight reservoirs, which depends to a large extent on the interaction between hydraulic and pre-existing cracks. For hydraulic fracturing of fractured reservoirs, the impact of natural fractures, perforation direction, stress disturbances, faults and other influencing factors will produce a mixed I&II mode hydraulic fracture. To forecast whether hydraulic fractures cross pre-existing fractures, according to elastic mecha.ics and fracture mecha.ics, a stress state of cracks under the combination of tensile(I) and shear(II) is presented. A simple mixed-mode I&II hydraulic fracture's crossing judgment criterion is established, and the propagation of hydraulic fractures after encountering natural fractures is analyzed. The results show tha. for a given approaching angle there exists a certain range of stress ratio when crossing occurs. Under high approaching angle and large stress ratio, it is likely tha. hydraulic cracks will go directly through pre-existing cracks. The reinitiated angle is always controlled within the range of approximately 30°among the main direction of penetration.

关键词： Crack propagation criterion Stress ratio Approaching angle Reinitiated angle Mecha.ical model