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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

Challenges and Opportunities of Sub-6 GHz Integrated Sensing and co.munications for 5G-Advanced and Beyond

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Chinese Journal of Electronics 2024年第2期33卷 323-325页

作者： Yuhong HUANG China Mobile Research Institute China Mobile co.munications group co. Ltd

The integrated sensing and co.munications(ISAC) technology has been perceived as a key feature of5G-Advanced and beyond mobile co.munication networks. co.pared with sensing in millimeter-wave bands, sensing at sub-6 GHz band is an exceptional incentive to promote the industrialization process of ISAC due to its inco.parable advantages in industrial development, especially for intelligent transportation and smart drone networks. This paper elaborates on the top challenges of sub-6 GHz ISAC technologies, as well as the potential solutions to improve the sensing capability.

关键词： Electric potential Millimeter wave technology Transportation Mobile co.munication Sensors Millimeter wave co.munication Drones

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

Fabricating functionally graded Fe-Cr-co.permanent magnetic alloys via laser powder bed fusion

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Journal of Iron and Steel Research International 2024年第3期31卷 729-737页

作者： Ya-zhou He Ya-qing Hou Peng Shen Hao Zhang Dong Zhou Hang Su Central Iron and Steel Research Institute co. Ltd.Beijing 100081China Material Digital R&D Center China Iron and Steel Research Institute Group Co.Ltd.Beijing 100081China

Laser powder bed fusion(LPBF)in-situ alloying technology offers the possibility to co.struct gradient materials with varied structures and *** graded Fe-Cr-co.permanent magnetic alloys were fabricated by LPBF and in-situ alloying mixed powders of Fe,Cr,and co.*** effects of different Fe,Cr and co.co.tents on the microstructure,magnetic properties and hardness of Fe-Cr-co.alloys prepared by LPBF were *** as-built Fe-Cr-co.alloys present a single body-centered-cubic phase and have a homogeneous distribution of *** mechanical properties and magnetic properties of the co.positionally graded sample show a gradient *** the increase in Cr co.tent,the Vickers hardness of the sample increases,and the saturation magnetization of the sample *** optimal magnetic properties in an isotropic state are given as co.rcivity HcB=21.65 kA/m,remanence Br=0.70 T and energy product(BH)_(max)=5.35 kJ/m^(3),which are co.parable to or higher than the reported magnetic properties in an isotropic state prepared by traditional powder *** in-situ alloying technology has the potential to further explore Fe-Cr-co.magnetic materials,such as those co.sisting of multiple or more co.stituent elements,and to maximize the co.positional flexibility of magnetic materials.

关键词： Fe-Cr-co.alloy Laser powder bed fusion In-situ alloying Functional material Magnetic property

Sludge co.position and characteristics shaped microbial co.munity and further determined process performance: A study on full-scale thermal hydrolysis-anaerobic digestion processes

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Journal of Environmental Sciences 2024年第3期137卷 96-107页

作者： Wei Liu Chenxiang Sun Wei Li Tianle Li Zhan Chen Jiawei Wang Zhengran Ren Xianghua Wen School of Environment Tsinghua UniversityBeijing 100084China Jinneng Holding group DatongShanxi 037000China Research and Development Center Beijing Drainage Group Co.Ltd.Beijing 100124China Beijing Dabeinong Science and Technology group co. Ltd.Beijing 100080China

Anaerobic digestion (AD) with thermal hydrolysis (TH) pretreatment is a promising process for excess sludge treatment,while there lacks of the knowledge from full-scale process about the impact of sludge co.position and characteristics on microbial co.munity and *** sludge physiochemical indices,microbial co.munity and performance data of four full-scale TH-AD plants were characterized,and their relationships was *** four plants were operated under almost similar total organic loading rate (OLR)but their methanogenesis performance differentiate into two groups,namely superior group(SupG) and the inferior group (Inf G).In both groups,TH effectively solubilized particulate organic co.pounds,meanwhile raised the ammonia nitrogen (NH_(4)^(+)-N) and volatile fatty acid (VFA) *** with the Sup G,thermal hydrolyzed sludge of Inf G had higher level of VFAs,NH_(4)^(+)-N and total chemical oxygen demand (t co.),which showed higher inhibition effect on microbes,leading to a co.munity with lower diversity,lower abundance of carbohydrate degrading functional guild,higher protein degrading one,and methanogens that adapted to limited substrates,and further declined the methane production ***,it was reco.mended that OLR alone was not sufficient for co.trolling the system in design and operation,the co.centration of VFAs,NH_(4)^(+)-N and t co. should be equally *** higher co.centration,together with the higher abundance of Defluviitoga and Proteiniphilum were reco.mended as indicators for inferior running *** results proposed that microbial co.munities played a role of bridge between environmental factors and performance,provided implications for engineering eco.ogy and operational regulation for full-scale sludge TH-AD process.

关键词： Thermal hydrolysis Anaerobic digestion Microbial co.munity Full-scale

Precipitation evolution and properties of Cu-15Ni-8Sn alloys via Al microalloying during ageing

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Rare Metals 2024年第10期43卷 5216-5228页

作者： Wei Luo Li-Jun Peng Xu-Jun Mi Hao-Feng Xie Yi-Cheng Cao Shu-Hui Huang State Key Laboratory of Nonferrous Metals and Processes GRINM Group Co.Ltd. GRIMAT Engineering Institute co. Ltd. General Research Institute for Nonferrous Metals School of Materials Science and Engineering South China University of Technology

Studies have shown that microalloying Cu-Ni-Sn alloys using Al inhibits disco.tinuous precipitation reactions;however,the mechanism has not been investigated ***,this study explored the properties and precipitation evolution of Cu-15Ni-8Sn alloys without and with 1 wt%Al（Cu-15Ni-8Sn-1Al） during ageing at 500℃ through X-ray diffraction （XRD）,scanning electron microsco.y and high-angle annular dark-field scanning transmission electron *** results revealed that in Cu-15Ni-8Sn alloy,DO22ordering first occurred after spinodal deco.position,subsequently transitioning to an L12ordering phase,during which the disco.tinuous precipitates gradually nucleated at the grain boundaries and formed *** alloy hardness increased sharply with ordering and then decreased rapidly after reaching its peak value,due to the dominance of the disco.tinuous precipitation ***,the DO22ordered phase did not appear during the ageing of Cu-15Ni-8Sn-1Al alloy,and a Ni3(Alx,Sn1-x) intermetallic co.pound with L12structure was formed,co.suming Ni and Sn atoms,thereby significantly suppressing the disco.tinuous precipitation reaction and improving the stability during prolonged *** tensile strength （yield strength） of Cu-15Ni-8Sn and Cu-15Ni-8Sn-1Al alloys at peak hardness were 855 （755） and 936 MPa （892 MPa）,respectively,and their main strengthening mechanisms were solid solution strengthening and precipitation *** addition of 1 wt% Al effectively improved the precipitation strengthening effect of Cu-Ni-Sn alloys but severely decreased the ductility.

关键词： Al addition Cu-15Ni-8Sn Precipitation sequence Strengthening mechanism

Mechanism of a dual-phase Ti-Nb alloy exhibiting near-linear elastic deformation

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Rare Metals 2024年第5期43卷 2282-2289页

作者： Yan Guo Wang Ding Wen Ma Shun Guo Hao-Dong Meng Nian-Yao Xu School of Automotive Engineering Changzhou Institute of TechnologyChangzhou 213032China School of Materials Science and Engineering Jiangsu UniversityZhenjiang 212013China Youke Publishing co. LtdChina Grinm Group Co.LtdBeijing 100088China

In this work,the underlying mechanism responsible for the near-linear elastic deformation behavior of a dual-phase Ti-Nb alloy co.sisting of β and α'' phase with large reco.erable strain was systematically *** on in situ synchrotron X-ray diffraction(SXRD)analyses,it was found that besides intrinsic elastic deformation,a slight reversible β-α'' stress-induced martensitic(SIM)transformation,which proceeded in a co.secutive mode under the retarding effect of micro-defects,took place during the near-linear elastic *** unloading,a small amount of residual macrosco.ic strain remained in the specimen due to the inco.plete reverse α''→β transformation on *** high near-linear elastic deformability of the co.d drawing(CD)Ti-Nb alloy has been revealed to be attributed to the co.pling actions of intrinsic elasticity as well as the co.secutive and reversible β-α'' SIM *** research may co.tribute to a new avenue for the design and development of novel dual-phase Ti-based alloys with desirable elastic deformability.

关键词： Titanium alloys Dual-phase Near-linear elastic deformation Martensitictransformation

Observer-based robust high-order fully actuated attitude autopilot design for spinning glide-guided projectiles

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Defence Technology（防务技术） 2024年第4期34卷 282-294页

作者： Wei Wang Yuchen Wang Shiwei Chen Yongcang Guo Zhongjiao Shi School of Aerospace Engineering Beijing Institute of TechnologyBeijing 10081China Northwest Industries group co. Ltd.Xi'an 710043China

This paper investigates the design of an attitude autopilot for a dual-channel co.trolled spinning glideguided projectile(SGGP),addressing model uncertainties and external *** on fixed-time stable theory,a disturbance observer with integral sliding mode and adaptive techniques is proposed to mitigate total disturbance effects,irrespective of initial *** introducing an error integral signal,the dynamics of the SGGP are transformed into two separate seco.d-order fully actuated ***,employing the high-order fully actuated approach and a parametric approach,the nonlinear dynamics of the SGGP are recast into a co.stant linear closed-loop system,ensuring that the projectile's attitude asymptotically tracks the given goal with the desired *** the proposed co.posite co.trol framework,the ultimately uniformly bounded stability of the closed-loop system is rigorously demonstrated via the Lyapunov *** of the effectiveness of the proposed attitude autopilot design is provided through extensive numerical simulations.

关键词： Spinning glide-guided projectile Attitude co.trol Sliding mode disturbance observer Fixed-time stable theory High-order fully actuated approach

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