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System design and validation of Queqiao-2 lunar relay co.munication satellite

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中国空间科学技术(中英文) 2024年第05期 23-39页

作者： ZHANG Lihua XIONG Liang SUN Ji CHEN Luojing XIAO Chuan ZHOU Wenyan WANG Yong LIU Wangwang GUAN Yifeng CHEN Tao YU Xiaochuan XU Jin CHEN Guohui CAO Xiaoping DFH Satellite co. Ltd. beijing Institute of spacecraft System Engineering beijing Institute of co.trol Engineering Academy of Space Information Systems

In order to provide relay co.munication supports for future Chinese lunar exploration program, Queqiao-2 relay co.munication satellite was ***-2 can perform scientific observations with three kinds of scientific instruments on *** system design of Queqiao-2,including mission orbit and transfer orbit design, co.figuration and layout design, housekeeping and information flow design, power supply and distribution design, GNC and propulsion system design, co.munication links design, etc.,was acco.plished through co.prehensive tradeoff and evaluation on technical maturity, availability, schedule, co.t, and so *** a view to reducing development risk, both the platform and relay co.munication payloads were developed based on significant heritage from previous Queqiao relay satellite and other relevant ***-2 features flexible system architecture to support multiple frequencies, modulations, data rates and software reco.figurations to meet new user *** to a successful launch on March 20,2024,by means of 5 orbit maneuvers, Queqiao-2 was inserted into a highly elliptical frozen mission orbit around the moon with a 24h period on *** on-orbit tests and calibrations, Queqiao-2 has possessed the capacity to provide reliable relay co.munication services to multiple lunar exploration missions, as well as the capacity to perform scientific *** the support of Queqiao-2,Chang′e-6 achieved its ambitious mission goal to co.lect and return samples from the moon′s mysterious far *** the meanwhile, Queqiao-2 has also paved the way for the following Chinese lunar exploration missions including Chang′e-7 and Chang′*** design life time of Queqiao-2 is more than 8 *** from flexibility and extensibility of relay co.munication system design, it is co.venient to provide relay co.munication services for future lunar exploration missions of both China and other *** addition, innovative

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Early-stage latent thermal failure of single-crystal Ni-rich layered cathode

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Journal of Energy Chemistry 2024年第9期96卷 578-587页

作者： Xiao Han Ruoyu Xu Yan Li Yang Ding Manchen Zhang Bo Wang Xiaoxing Ke Manling Sui Pengfei Yan beijing Key Laboratory of Microstructure and Property of Solids Faculty of Materials and ManufacturingBeijing University of TechnologyBeijing 100124China Watt Laboratory Central Research InstituteHuawei Technologies Co.LTDShenzhen 518129GuangdongChina

High nickel co.tent worsens the thermal stability of layered cathodes for lithium-ion batteries,raising safety co.cerns for their *** understanding the thermal failure process can offer valuable guidance for material optimization on thermal stability and new opportunities in monitoring battery thermal runaway(TR).Herein,this work co.prehensively investigates the thermal failure process of a single-crystal nickel-rich layered cathode and finds that the latent thermal failure starts at∼120℃far below the TR temperature(225℃).During this stage of heat accumulation,sequential structure transition is revealed by atomic resolution electron microsco.y,which follows the layered→cation mixing layered→LiMn_(2)O_(4)-type spinel→disordered spinel→rock *** progression occurs as a result of the co.tinuous migration and densification of transition metal *** transition generates gaseous oxygen,initially co.fined within the isolated closed pores,thereby not showing any thermal failure phenomena at the *** temperature leads to pore growth and co.lescence,and eventually to the formation of open pores,causing oxygen gas release and weight loss,which are the typical TR *** highlight that latent thermal instability occurs before the macro-level TR,suggesting that suppressing phase transitions caused by early thermal instability is a crucial direction for material *** findings can also be used for early warning of battery thermal runaway.

关键词： Thermal runaway Nickel-rich layered cathode Transmission electron microsco.y Lithium-ion battery Phase transition

Vibration co.trol of the Rail Grinding Vehicle with Abrasive Belt Based on Structural Optimization and Lightweight Design

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Chinese Journal of Mechanical Engineering 2024年第3期37卷 311-337页

作者： Wengang Fan Shuai Zhang Zhiwei Wu Yi Liu Jiangnan Yu School of Mechanical Electronic and Control EngineeringBeijing Jiaotong UniversityBeijing 100044China Key Laboratory of Vehicle Advanced manufacturing Measuring and Control TechnologyMinistry of EducationBeijing 100044China China Railway Materials Operation and Maintenance Technology co. LtdBeijing 100036China

As a new grinding and maintenance technology,rail belt grinding shows significant advantages in many applications The dynamic characteristics of the rail belt grinding vehicle largely determines its grinding performance and service *** order to explore the vibration co.trol method of the rail grinding vehicle with abrasive belt,the vibration response changes in structural optimization and lightweight design are respectively analyzed through transient response and random vibration simulations in this ***,the transient response simulation analysis of the rail grinding vehicle with abrasive belt is carried out under operating co.ditions and non-operating ***,the vibration co.trol of the grinding vehicle is implemented by setting vibration isolation elements,optimizing the structure,and increasing ***,in order to further explore the dynamic characteristics of the rail grinding vehicle,the random vibration simulation analysis of the grinding vehicle is carried out under the co.dition of the horizontal irregularity of the American AAR6 ***,by replacing the Q235 steel frame material with 7075 aluminum alloy and LA43M magnesium alloy,both vibration co.trol and lightweight design can be achieved *** results of transient dynamic response analysis show that the acceleration of most positions in the two working co.ditions exceeds the standard value in GB/T 17426-1998 *** optimizing the structure of the grinding vehicle in three ways,the average vibration acceleration of the whole car is reduced by about 55.1%from 15.6 m/s^(2) to 7.0 m/s^(2).The results of random vibration analysis show that the grinding vehicle with Q235 steel frame does not meet the safety co.ditions of 3σ.By changing frame material,the maximum vibration stress of the vehicle can be reduced from 240.7 MPa to 160.0 MPa and the weight of the grinding vehicle is reduced by about 21.7%from 1500 kg to 1175 *** modal analysis results indic

关键词： Vibration co.trol Dynamic characteristics Structural optimization Lightweight design Modal analysis

Occurrence and vertical distribution of aluminum and rare earths in weathered crust elution-deposited rare earth ore:Effect of soil solution pH and clay minerals

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Journal of Rare Earths 2024年第7期42卷 1394-1402,I0007页

作者： Jiaxin Pan Longsheng Zhao Zheng Li Xiaowei Huang Zongyu Feng Jun Chen National Engineering Research Center for Rare Earth China GRINM Group Co.Ltd.Beijing100088China School of Metallurgical and Eco.ogical Engineering University of Science and Technology Beijing(USTB)Beijing100083China GRIREM Hi–Tech co. Ltd.Langfang065201China GRIREM Advanced Materials co. Ltd.Beijing100088China GRIMAT Engineering Institute co. Ltd.Beijing101407China

Weathered crust elution-deposited rare earth ore is crucial source of medium and heavy rare earths,with in-situ leaching being the most co.mon mining *** high co.tents of impurity of aluminum in the leach solution are a significant challenge for the subsequent enrichment process of rare earths.A co.prehensive understanding of the occurrences and vertical distribution of aluminum and rare earths within typical vertical profiles can provide valuable insights into entire design of the in-situ *** paper improves a five-step sequential extraction method to analyze the occurrence and vertical distribution of rare earths and aluminum in vertical profiles from Chongzuo and *** results demonstrate that soil solution pH is the main factor affecting the vertical distribution of ionexchangeable rare *** samples have distinct areas of enrichment for ion-exchangeable rare earths or ***-exchangeable rare earths are primary co.centrated in the middle and lower parts of the ore layer(4-13 m in Chongzuo,14-22 m in Longyan),while the ion-exchangeable aluminum is mainly enriched in the upper part of the ore layer(1-5 m in Chongzuo,and 2-14 m in Longyan).The vertical distribution of inorganic hydroxy aluminum is likely influenced by the micromorphology and particle size of the clay *** inorganic hydroxy aluminum co.centration in Chongzuo samples decreases co.tinuously from 415.65 to 120.95 mg/kg with increasing sampling depth,whereas the co.centration in Longyan samples(110.55-171.27 mg/kg)is almost independence with sampling *** results provide direct guidance for the entire design of the injection well depth and the leaching parameters,thereby inhibiting the leaching of impurity of aluminum and lower the co.sumption of leaching agent.

关键词： Weathered crust elution-deposited rare earth ore Sequential extraction Occurrence Aluminum Rare earth elements

Effects of deformation temperatures on microstructures,aging behaviors and mechanical properties of Mg-Gd-Er-Zr alloys fabricated by hard-plate rolling

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Journal of Magnesium and Alloys 2024年第6期12卷 2345-2359页

作者： Ke Liu Dalong Hu Feng Lou Zijian Yu Shubo Li Xian Du Wenbo Du Faculty of Materials and manufacturing Beijing University of TechnologyBeijing 100124China

In this investigation,a high-strength Mg-12Gd-1.0Er-0.5Zr(wt.%)alloy sheet was produced by hot extrusion(HE)and subsequent hard-plate rolling(HPR)at different *** results indicate that the microstructures of these final-rolled sheets are inhomogeneous,mainly including co.rse deformed grains and dynamic recrystallized(DRXed)grains,and the volume fraction of these co.rse deformed grains increases as the rolling temperature ***,more DRXed grains can be found in R-385℃sheet,resulting in a smaller average grain size and weaker basal texture,while the biggest grains and the highest strong basal texture are present in R-450℃*** of dynamic precipitation ofβphases which are mainly determined by the rolling temperature are present in these sheets,and its precipitation can co.sume the co.tent of Gd solutes in the *** a result,the lowest number density ofβphase in R-450℃sheet is beneficial to modify the age hardening ***,the R-450℃sheet displays the best age hardening response because of a severe traditional precipitation ofβ’(more)andβH/βM(less)precipitates,resulting in a sharp improvement in strength,*** tensile strength(UTS)of∼518±17 MPa and yield strength(YS)of∼438±18 ***,the elongation(EL)of this sheet reduces greatly,and its value is∼2.7±0.3%.By co.trasting,the EL of the peak-aging R-385℃sheet keeps better,changing from∼4.9±1.2%to∼4.8±1.4%due to a novel dislocation-induced chain-like precipitate which is helpful to keep good balance between strength and ductility.

关键词： Mg-Gd-Er-Zr sheets Age hardening response Precipitates Mechanical properties

Solidification behaviour and hot cracking susceptibility of a novel Ni-based superalloy

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Journal of Iron and Steel Research International 2024年第4期31卷 956-966页

作者： Yue Chen Shao-min Lv Xing-fei Xie Xiao-can Wen Jng-long Qu Jin-hui Du High-Temperature Materials Institute China Iron and Steel Research Institute Group Co.Ltd.Beijing 100081China beijing GAONA Materials and Technology co. Ltd.Beijing 100081China Sichuan CISRI-GAONA Forging co. Ltd.Deyang 610000SichuanChina

A novel Ni-based superalloy GH4151,with a γ′ volume fraction of about 55%and a service temperature capability up to 8oo oC,was *** to the different co.ling co.ditions of various regions during the solidification of ingots,significant co.ling rate variations may lead to the occurrence of hot *** scanning laser microsco.e was utilised to investigate the solidification process and phase precipitation behaviour of the GH4151 under wide range co.ling *** characteristics of L→γ transformation were analysed,and the growth rates of at each stage were *** segregation behaviour was predicted using the Scheil equation,and the predicted results match well with the experimental *** sensitivity co.fficient for hot cracking was modified,and cracking sensitivity co.fficient values for the alloy under different co.ling rates were co.puted,revealing that the alloy is most susceptible to hot cracking at 10℃/min co.ling ***,co.trolling the co.ling rate can reduce the possibility of hot cracking in ingot.

关键词： Ni-based superalloy Solidification behaviour In-situ observation Clyne and Davies's criterion:Hot cracking susceptibility

Preparation and Rheological Characterization of Long Chain Branching Polyglyco.ide

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Chinese Journal of Polymer Science 2024年第8期42卷 1177-1184页

作者： Wei-Lin Liu Ming-Fu Lyu Heng-Yuan Zhang Jian-Ye Liu Shi-Jun Zhang beijing University of Chemical Technology Beijing 100029China SINOPEC(beijing)Research Institute of Chemical Industry co. Ltd.Beijing 100013China

The long chain branching(LCB)polyglyco.ide(PGA)was successfully prepared by the successive reactions of the terminal hydroxyl groups of PGA with triglycidyl isocyanurate(TGIC)and pyromellitic dianhydride(PMDA).The influence of LCB produced by functional group reaction on rheological and crystallization behavior was studied and discussed through linear rheology,uniaxial elongation and DSC(differential scanning calorimetry).The much higher visco.ity and the more notable strain hardening behavior of modified PGA indicates the LCB with high degree of entanglements are *** melt strength of PGA is finally improved greatly and can make su re that the supercritical co.(2)foaming can be carried out successfully.

关键词： Polyglyco.ide(PGA) Long chain branching(LCB) Rheology

Tungsten separation behavior on preparation of high-purity cerium by co.bined vacuum gravity sedimentation-directional solidification

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Journal of Rare Earths 2024年第6期42卷 1182-1186,I0007页

作者： Dongwei Zhang Wenli Lu Minglei Xu Dehong Chen Xiaowei Zhang Chuang Yu Wensheng Yang Ruifeng Dong Zhiqiang Wang Liguo Han Zengdong Pang GRIREM Hi-Tech co. Ltd.Langfang065201China National Engineering Research Center for Rare Earth China GRINM Group Co.Ltd.Beijing100088China GRIREM Advanced Materials co. Ltd.Beijing100088China

In light of the difficult removal of harmful impurity tungsten(W)in Ce metal,in this paper a co.bined vacuum gravity sedimentation-directional solidification method was innovatively designed and the W separation behavior was *** reducing the electron beam power instantly and gradually at reduction rates of 1,3 and 5 kW/min,it is found that W is enriched at the bottom of ingots as the melt *** enrichment effect is much better than that of single purification method and the enrichment degree increases as the beam reduction rate decreases,attributed to the k0(W)>1 andρ(W)>ρ(Ce).Overall,the minimum co.tent of W impurity can decrease from 630 to 0.1 ppm at the top of the ingot,and the purity of Ce increases from 99.932 wt%to 99.995 wt%by this co.bined ***,this paper provides a new method for the removal of high density and low evaporation co.fficient impurities in low vapor pressure rare earth metals.

关键词： Cerium Electron beam melting Directional solidification Gravity sedimentation Rare earths

State of the art in movement around a remote point:a review of remote center of motion in robotics

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Frontiers of Mechanical Engineering 2024年第2期19卷 1-28页

作者： Wuxiang ZHANG Zhi WANG Ke MA Fei LIU Pengzhi CHENG Xilun DING School of Mechanical Engineering and Automation Beihang UniversityBeijing 100191China Ningbo Institute of Technology Beihang UniversityNingbo 315832China Intelligent Aerospace manufacturing Engineering Technology co. Ltd.Beijing 100191China

The co.cept of remote center of motion(RCM)is pivotal in a myriad of robotic applications,enco.pa-ssing areas such as medical robotics,orientation devices,and exoskeletal *** efficacy of RCM technology is a determining factor in the success of these robotic *** paper offers an exhaustive review of RCM technologies,elaborating on their various methodologies and practical *** delves into the unique characteristics of RCM across different degrees of freedom(DOFs),aiming to distill their fundamental *** addition,this paper categorizes RCM approaches into two primary classifications:design based and co.trol *** are further organized acco.ding to their respective DOFs,providing a co.cise summary of their co.e *** upon the understanding of RCM’s versatile capabilities,this paper then transitions to an in-depth exploration of its applications across diverse robotic *** this review,we critically analyze the existing research challenges and issues that are inherently present in both RCM methodologies and their *** discussion is intended to serve as a guiding framework for future research endeavors and practical deployments in related areas.

关键词： remote center of motion mechanism robotics medical robot orientation device exoskeleton