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Mechanism of local solidification time variations with melt rate during vacuum arc remelting process of 8Cr4Mo4V high-strength steel

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Journal of Iron and Steel Research(International) 2024年第2期31卷 377-388页

作者： Tao Pan Hong-chun Zhu Zhou-hua jiang hua-bing Li Rui zhang Hao Feng School of Metallurgy Northeastern UniversityShenyang110819LiaoningChina State Key Laboratory of Rolling and Automation Northeastern UniversityShenyang110819LiaoningChina

A 2D axisymmetric numerical model was established to investigate the variations of molten pool with different melt rates during the vacuum arc remelting of 8Cr4Mo4V high-strength steel,and the ingot growth was simulated by dynamic mesh techniques.The results show that as the ingot grows,the molten pool profile changes from shallow and flat to V-shaped,and both the molten pool depth and the mushy width increase.Meanwhile,the variation of both the molten pool shape and the mushy width melt rate is clarified by the thermal equilibrium analysis.As melt rate increases,both the molten pool depth and the mushy width increase.It is caused by the increment in sensible heat stored in the ingot due to the limitation of the cooling capacity of the mold.The nonlinear increment in sensible heat leads to a nonlinear increase in the mushy width.In addition,as melt rate increases,the local solidification time(LST)of ingot decreases obviously at first and then increases.When melt rate is controlled in a suitable range,LST is the lowest and the secondary dendrite arm spacing of the ingot is the smallest,which can effectively improve the compactness degree of 8Cr4Mo4V high-strength steel.

关键词： 8Cr4Mo4V high-strength steel Vacuum arc remelting process Melt rate Molten pool Local solidification time

PACS gene family-related neurological diseases: limited genotypes and diverse phenotypes

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World Journal of Pediatrics 2024年第1期20卷 82-91页

作者： Han zhang Kai Gao Shuang Wang Yue-hua zhang Zhi-Xian Yang Ye Wu Yu-Wu jiang Department of Pediatrics Peking University First Hospital.No.1 Xi'an Men StreetWest DistrictBeijing 100034China Bejing Key Laboratory of Molecular Diagnosis and Study on Pediatric Genetic Diseases BeijingChina Children Epilepsy Center Peking University First HospitalBeijingChina Key Laboratory for Neuroscience Ministry of Education/National Health and Family Planning CommissionPeking UniversityBeijingChina Center of Epilepsy Beijing Institute for Brain DisordersBeijingChina

Background The PACS gene family has been demonstrated to be related to intracellular vesicular trafficking.The phenotypic manifestations caused by the pathogenic variants of PACS include epilepsy,intellectual disability/developmental delay,and malformations,such as facial abnormalities.Methods We identified seven new cases with pathogenic or likely pathogenic PACS variants using next-generation sequencing.Detailed information obtained from these patients was analyzed along with that obtained from previously reported patients.Results With the inclusion of the newly diagnosed cases in this study,103 cases with PACS gene family-related neurological diseases were reported,of which 43 were PACS2-related cases and the remaining were PACSI-related cases.Most patients had seizures,which have been reported to be effectively controlled by several types of anti-seizure medications(ASMs).The most efficacious and frequently prescribed ASMs included sodium valproate(43.3%,13/30),oxcarbazepine/carbamazepine(26.7%,8/30),and levetiracetam(20%,6/30).Almost all patients had intellectual disability/developmental delay.The most common pathogenic missense variants were PACSI p.Arg203Trp and PACS2 p.Glu209Lys.In addition,we report a patient carrying a likely pathogenic copy number variation(CNV)(de novo heterozygous deletion of chr14:105821380-106107443,286 kilobase,destroyed part of the furin-binding region domain and the protein structure after it)with more severe and refractory late-onset epilepsy.Conclusions The clinical phenotypes of the different PACS heterozygous missense variants were similar.The pathogenic variant sites of PACSI and PACS2 were quite limited but located in different regions.A CNV destroying part of the PACS2 gene might also be pathogenic.These findings may provide an important clue for further functional studies on the pathogenic mechanism of neurological disorders related to the PACS gene family.

关键词： Developmental delay Epilepsy Intellectual disability PACSI PACS2

Part-Whole Relational Few-Shot 3D Point Cloud Semantic Segmentation

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Computers, Materials & Continua 2024年第3期78卷 3021-3039页

作者： Shoukun Xu Lujun zhang Guangqi jiang Yining hua Yi Liu School of Computer Science and Artificial Intelligence Aliyun School of Big Data and School of SoftwareChangzhou UniversityChangzhou213164China Department of Computer Science University of AberdeenKing’s CollegeAberdeenAB243FXUK

This paper focuses on the task of few-shot 3D point cloud semantic segmentation.Despite some progress,this task still encounters many issues due to the insufficient samples given,e.g.,incomplete object segmentation and inaccurate semantic discrimination.To tackle these issues,we first leverage part-whole relationships into the task of 3D point cloud semantic segmentation to capture semantic integrity,which is empowered by the dynamic capsule routing with the module of 3D Capsule Networks(CapsNets)in the embedding network.Concretely,the dynamic routing amalgamates geometric information of the 3D point cloud data to construct higher-level feature representations,which capture the relationships between object parts and their wholes.Secondly,we designed a multi-prototype enhancement module to enhance the prototype discriminability.Specifically,the single-prototype enhancement mechanism is expanded to the multi-prototype enhancement version for capturing rich semantics.Besides,the shot-correlation within the category is calculated via the interaction of different samples to enhance the intra-category similarity.Ablation studies prove that the involved part-whole relations and proposed multi-prototype enhancement module help to achieve complete object segmentation and improve semantic discrimination.Moreover,under the integration of these two modules,quantitative and qualitative experiments on two public benchmarks,including S3DIS and ScanNet,indicate the superior performance of the proposed framework on the task of 3D point cloud semantic segmentation,compared to some state-of-the-art methods.

关键词： Few-shot point cloud semantic segmentation CapsNets

On the Pathwise Uniqueness of Solutions of One-dimensional Reflected Stochastic Differential Equations with Jumps

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Acta Mathematicae Applicatae Sinica 2024年第1期40卷 149-163页

作者： hua zhang School of Statistics and Data Science&Key Laboratory of Data Science in Finance and Economics Jiangxi University of Finance and EconomicsNanchang330013China

In this paper, we are concerned with the problem of the pathwise uniqueness of one-dimensional reflected stochastic differential equations with jumps under the assumption of non-Lipschitz continuous coefficients whose... 详细信息

关键词： reflected diffusion processes with jumps pathwise uniqueness local time Meyer It?'s formula

Research on the design method for uniform wear of shield cutters in sand-pebble strata

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Deep Underground Science and Engineering 2024年第2期3卷 216-230页

作者： Jinxun zhang Bo Li Guihe Wang Yusheng jiang hua jiang Minglun Yin Zhengyang Sun Beijing Urban Construction Group Co. Ltd.BeijingChina China University of Geosciences BeijingChina China University of Mining and Technology BeijingChina

During shield tunneling in highly abrasive formations such as sand–pebble strata,nonuniform wear of shield cutters is inevitable due to the different cutting distances.Frequent downtimes and cutter replacements have become major obstacles to long-distance shield driving in sand–pebble strata.Based on the cutter wear characteristics in sand–pebble strata in Beijing,a design methodology for the cutterhead and cutters was established in this study to achieve uniform wear of all cutters by the principle of frictional wear.The applicability of the design method was verified through three-dimensional simulations using the engineering discrete element method.The results show that uniform wear of all cutters on the cutterhead could be achieved by installing different numbers of cutters on each trajectory radius and designing a curved spoke with a certain arch height according to the shield diameter.Under the uniform wear scheme,the cutter wear coefficient is greatly reduced,and the largest shield driving distance is increased by approximately 47%over the engineering scheme.The research results indicate that the problem of nonuniform cutter wear in shield excavation could be overcome,thereby providing guiding significance for theoretical innovation and construction of long-distance shield excavation in highly abrasive strata.

关键词： cutter wear EDEM model long-distance shield driving sand-pebble stratum shield tunnel uniform wear design method

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Harnessing cytokine-induced killer cells to accelerate diabetic wound healing: an approach to regulating post-traumatic inflammation

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Regenerative Biomaterials 2024年第2期3卷 88-99页

作者： Yixi Yang Cheng zhang Yuan jiang Yijun He iawei Cai Lin Liang Zhaohuan Chen Sicheng Pan Chu hua Keke Wu Le Wang Zhiyong zhang Translational Research Centre of Regenerative Medicine and 3D Printing of Guangzhou Medical University Guangdong Province Engineering Research Center for Biomedical EngineeringState Key Laboratory of Respiratory DiseaseDepartment of Orthopaedic SurgeryMedical Technology and Related Equipment Research for Spinal Injury TreatmentCity Key LaboratoryThe Third Affliated Hospital of Guangzhou Medical UniversitySchool of Biomedical EngineeringGuangzhou MedicalUniversityGuangzhouGuangdong510150P.R.China Department of Osteoarthropathy and Sports Medicine Panyu Central HospitalGuangzhou 511400P.R.China

Impaired immunohomeostasis in diabetic wounds prolongs infiammation and cytokine dysfunction,thus,delaying or pre-venting wound-surface healing.Extensive clinical studies have been conducted on cytokine-induced killer(CIK)cells recently,as they can be easily proliferated using a straightforward,inex-pensive protocol.Therefore,the function of CIK cells in regulat-ing inflammatory environments has been drawing attention for clinical management.Throughout the current investigation,we discovered the regenerative capacity of these cells in the chal-lenging environment of wounds that heal poorly due to diabe-tes.We demonstrated that the intravenous injection of CIK cells can re-establish a proregenerative inflammatory microenviron-ment.promote larizationand.ultimatel accelerateskin healing in diabetic mice.The results indicated that CIK cell treatment affects macrophage polarization and restores the function regenerative cells under hyperglycemic conditions.This novel cellular therapy offers a promising intervention for clinical applic tions through specific inflammatory regulation functions.

关键词： macrophage diabetic wound post-traumatic inflammation cytokine-induced killer cells vascularization

Electrocatalytic performance of CNTs/graphene composited rare earth phthalocyanines(M=La,Y,Yb,Sc)

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Journal of Rare Earths 2024年第2期42卷 323-333,I0004页

作者： Tingting jiang Caixia Ou Luyi Wang Jun Chen Sydorov Dmytro Qian zhang Jintian Luo hua Wang jiangxi Key Laboratory of Power Batteries and Materials Faculty of Materials Metallurgy and ChemistryJiangxi University of Science and TechnologyGanzhou341000China Joint Department of Electrochemical Energy Systems Institute of Bioorganic Chemistry and PetrochemistryNational Academy of Sciences of Ukraine38A VernadskyAveKiev03142Ukraine Guangdong Jiana Energy Technology Co. Ltd.Qingyuan511500China

In this study,a class of rare earth composite sandwich phthalocyanines(MPcs,M=La,Y,Yb,Sc) were prepared and compounded with graphene and carbon nanotubes to obtain MPc/Gr and MPc/CNTs composites.The electrocatalytic behaviors of MPc/Gr and MPc/CNTs electrodes were further investigated.The results show that the central rare earth metal has a large influence on the electrocatalytic performance.For the MPcs/Gr samples,ScPc with the smallest ionic radius and molecular size can be more uniformly dispersed in graphene,and the hydrogen precipitation overpotential of ScPc/Gr electrode is514 mV,corresponding to a Tafel slope of 148 mV/dec,with better electrocatalytic performance than other rare earth metal phthalocyanines.As for the MPc/CNTs composites,LaPc,which has the largest ionic radius and molecular size,is more uniformly dispersed on the surface of CNTs,so that the LaPc/CNT electrode exhibits the best LSV performance with the smallest corresponding Tafel slope(176 mV/dec).The main reason is the different binding modes of MPcs molecules in Gr and CNTs.When rare earth phthalocyanine is combined with layered graphene,the smallest size of rare earth phthalocyanine(ScPc)is more easily embedded in the graphene layer,resulting in better homogeneity of the composite,larger effective contact area and better electrocatalytic performance.In contrast,when rare earth phthalocyanine is bound to carbon nanotubes in a tubular structure,it is mainly bound by attaching to the surface or being entangled by the carbon nanotubes.In this case,the rare-earth phthalocyanine molecules(LaPc)with larger layer spacing can provide more contact area with CNTs,forming a more uniform and effective composite,which eventually provides more active sites and better electrocatalytic performance.

关键词： Electrocatalysis Rare earth phthalocyanines Graphene(Gr) Carbon nanotubes(CNTs) Composite

Effects of NO_(2) and SO_(2) on the secondary organic aerosol formation fromβ-pinene photooxidation

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Journal of Environmental Sciences 2024年第2期136卷 151-160页

作者： Xiangyu Zang Zhaoyan zhang Yingqi Zhao Gang Li hua Xie Weiqing zhang Guorong Wu Xueming Yang Ling jiang zhang Dayu School of Chemistry Dalian University of TechnologyDalian 116024China State Key Laboratory of Molecular Reaction Dynamics Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023China University of Chinese Academy of Sciences Beijing 100049China Department of Chemistry School of ScienceSouthern University of Science and TechnologyShenzhen 518055China

Elucidating the effects of anthropogenic pollutants on the photooxidation of biogenic volatile organic compounds is crucial to understanding the fundamental mechanisms of secondary organic aerosol(SOA)formation.Here,the impacts of NO_(2)and SO_(2)on SOA formation from the photooxidation of a representative monoterpene,β-pinene,were investigated by a number of laboratory studies.The results indicated NO_(2)enhanced the SOA mass concentrations and particle number concentrations under both low and highβ-pinene conditions.This could be rationalized that the increased O_(3)concentrations upon the NO_(x)photolysis was helpful for the generation of more amounts of O_(3)-oxidized products,which accelerated the SOA nucleation and growth.Combing with NO_(2),the promotion of the SOA yield by SO_(2)was mainly reflected in the increase of mass concentration,which might be due to the elimination of the newly formed particles by the initially formed particles.The observed low oxidation degree of SOA might be attributed to the fast growth of SOA,resulting in the uptake of less oxygenated gas-phase species onto the particle phase.The present findings have important implications for SOA formation affected by anthropogenic–biogenic interactions in the ambient atmosphere.

关键词： Secondary organic aerosol Volatile organic compound Anthropogenic pollutant Beta-pinene Photooxidation

Wireless Positioning:Technologies,Applications,Challenges,and Future Development Trends

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Computer Modeling in Engineering & Sciences 2024年第5期139卷 1135-1166页

作者： Xingwang Li hua Pang Geng Li Junjie jiang Hui zhang Changfei Gu Dong Yuan School of Physics and Electronic Information Engineering University of Henan PolytechnicJiaozuo454000China Jiaozuo Key Laboratory of Crow-Sensing Network Jiaozuo454000China Institute of Mining Engineering Guizhou Institute of TechnologyGuiyang550003China Coal Supervision Department Panzhou Energy BureauPanzhou553599China

The development of the fifth-generation(5G)mobile communication systems has entered the commercialization stage.5G has a high data rate,low latency,and high reliability that can meet the basic demands of most industries and daily life,such as the Internet of Things(IoT),intelligent transportation systems,positioning,and navigation.The continuous progress and development of society have aroused wide concern.Positioning accuracy is the core demand for the applications,especially in complex environments such as airports,warehouses,supermarkets,and basements.However,many factors also affect the accuracy of positioning in those environments,for example,multipath effects,non-line-of-sight,and clock synchronization errors.This paper provides a comprehensive review of the existing works about positioning for the future wireless network and discusses its key techniques and algorithms,as well as the current development and future directions.We first outline the current traditional positioning technologies and algorithms,which are discussed and analyzed with the relevant literature.In addition,we also discuss application scenarios for wireless localization.By comparing different positioning systems,the challenges and future development directions of existing wireless positioning systems are prospected.

关键词： 5G wireless positioning reconfigurable intelligent surface Internet of Vehicles