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Effects of minor Nd and Er additions on the precipitation evolution and dynamic recrystallization behavior of Mg-6.0Zn-0.5Mn alloy

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Journal of Magnesium and Alloys 2021年第3期9卷 840-852页

作者： Bin-Jiang Lv Sen Wang tie-wei xu Feng Guo School of Mechanical and Automotive Engineering Qingdao University of Technology266520China Key Lab of industrial Fluid Energy Conservation and Pollution Control Qingdao University of Technology266520China

A new wrought magnesium(Mg)alloy based on Mg-6.0Zn-0.5Mn(ZM60)is developed,which performs excellent combination of high tensile yield strength and good *** investigate the effects of micro-alloying on dynamic precipitation,dynamic recrystallization(DRX)and mechanical properties of ZM60 *** co-addition of minor(0.6 wt%)neodymium(Nd)and(0.3 wt%)erbium(Er)can accelerate the twinning and DRX process of ZM60 alloy at the initial compression deformation *** dynamic precipitation process is also accelerated due to Nd and Er *** accumulation disappears and a higher density of rodβ_(1) precipitates and some thick β_(2) precipitates in matrix and fine twins,which inhibits the growth of DRX grains in compressed ZM60-0.6Nd-0.3Er *** as-extruded ZM60-0.6Nd-0.3Er alloy has a yield strength(YS)of 245.8 MPa,ultimate tensile strength(UTS)of 347.2 MPa and elongation(EL)of 16.3%.The yield strength and tensile strength are improved via minor Nd and Er additions due to fine complete DRX grains,second phase particles and high density of *** grain refinement,weakened reserved working hardening and weakened basal fiber texture improve the elongation of ZM60-0.6Nd-0.3Er alloy.

关键词： Nd and Er Hot deformation Dynamic precipitation Dynamic recrystallization Texture

Machine learning-based performance predictions for steels considering manufacturing process parameters:a review

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Journal of Iron and Steel Research International 2024年第7期31卷 1555-1581页

作者： wei Fang Jia-xin Huang tie-xu Peng Yang Long Fu-xing Yin Tianjin Key Laboratory of Materials Laminating Fabrication and Interface Control Technology School of Materials Science and EngineeringHebei University of TechnologyTianjin 300132China Institute of New Materials Guangdong Academy of ScienceGuangzhou 510651GuangdongChina

Steels are widely used as structural materials,making them essential for supporting our lives and ***,further improving the comprehensive properties of steel through traditional trial-and-error methods becomes challenging due to the continuous development and numerous processing parameters involved in steel *** address this challenge,the application of machine learning methods becomes crucial in establishing complex relationships between manufacturing processes and steel *** review begins with a general overview of machine learning methods and subsequently introduces various performance predictions in steel *** classification of performance pre-diction was used to assess the current application of machine learning model-assisted *** important issues,such as data source and characteristics,intermediate features,algorithm optimization,key feature analysis,and the role of environmental factors,were summarized and *** insights will be beneficial and enlightening to future research endeavors in this field.

关键词： Steel Manufacturing process Machine learning Performance prediction Algorithm

Macroscopic model and statistical model to characterize electromagnetic information of a digital coding metasurface

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National Science Review 2024年第03期11卷 159-171页

作者： Rui Wen Shao Jun wei Wu Zheng Xing Wang Hui xu Han Qing Yang Qiang Cheng tie Jun Cui Institute of Electromagnetic Space Southeast University State Key Laboratory of Millimeter Waves Southeast University Peng Cheng Laboratory Pazhou Laboratory(Huangpu)

A digital coding metasurface is a platform connecting the digital space and electromagnetic wave space, and has therefore gained much attention due to its intriguing value in reshaping wireless channels and realizing new communication architectures. Correspondingly, there is an urgent need for electromagnetic information theory that reveals the upper limit of communication capacity and supports the accurate design of metasurface-based communication systems. To this end, we propose a macroscopic model and a statistical model of the digital coding metasurface. The macroscopic model uniformly accommodates both digital and electromagnetic aspects of the meta-atoms and predicts all possible scattered fields of the digital coding metasurface based on a small number of simulations or measurements. Full-wave simulations and experimental results show that the macroscopic model is feasible and accurate. A statistical model is further proposed to correlate the mutual coupling between meta-atoms with covariance and to calculate the entropy of the equivalent currents of digital coding metasurface. These two models can help reconfigurable intelligent surfaces achieve more accurate beamforming and channel estimation, and thus improve signal power and coverage. Moreover, the models will encourage the creation of a precoding codebook in metasurface-based direct digital modulation systems, with the aim of approaching the upper limit of channel capacity. With these two models, the concepts of current space and current entropy, as well as the analysis of information loss from the coding space to wave space, is established for the first time, helping to bridge the gap between the digital world and the physical world, and advancing developments of electromagnetic information theory and new-architecture wireless systems.

关键词： electromagnetic information theory current entropy current space digital coding metasurface macroscopic model statistical model

Rupture of a giant jejunal mesenteric cystic lymphangioma misdiagnosed as ovarian torsion: A case report

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World Journal of Clinical Cases 2024年第4期12卷 847-852页

作者： Jing xu tie-Feng Lv Department of Hepatopathy Hangzhou Xixi HospitalHangzhou 310023Zhejiang ProvinceChina

BACKGROUND Cystic lymphangioma is a rare benign tumor that affects the lymphatic *** lymphangiomas in the small bowel are extremely *** SUMMARY We present a 21-year-old female patient who complained of abdominal *** diagnosis of ovarian torsion was suspected after abdominopelvic unenhanced computed tomography and ultrasound revealed a large cyst in contact with the bladder,ovary,and *** patient underwent emergency laparotomy per-formed by gynecologists,but it was discovered that the cystic tumor originated from the *** surgeons were then called in to perform a *** examination confirmed the diagnosis of cystic lymphangioma of the *** patient had an uneventful postoperative *** Mesenteric lymphangiomas can cause abdominal pain,and imaging techniques can help determine their characteristics,location,and *** surgical excision and pathological examination are considered the standard treatment and diagnostic method.

关键词： Rupture Jejunum Mesenteric cystic lymphangioma Ovarian torsion Surgical excision Pathological examination Case report

A real-time intelligent lithology identification method based on a dynamic felling strategy weighted random forest algorithm

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Petroleum Science 2024年第2期21卷 1135-1148页

作者： tie Yan Rui xu Shi-Hui Sun Zhao-Kai Hou Jin-Yu Feng School of Petroleum Engineering Northeast Petroleum UniversityDaqing163318HeilongjiangChina Sanya Offshore Oil&Gas Research Institute Northeast Petroleum UniversitySanya572025HainanChina

Real-time intelligent lithology identification while drilling is vital to realizing downhole closed-loop drilling. The complex and changeable geological environment in the drilling makes lithology identification face many challenges. This paper studies the problems of difficult feature information extraction,low precision of thin-layer identification and limited applicability of the model in intelligent lithologic identification. The author tries to improve the comprehensive performance of the lithology identification model from three aspects: data feature extraction, class balance, and model design. A new real-time intelligent lithology identification model of dynamic felling strategy weighted random forest algorithm(DFW-RF) is proposed. According to the feature selection results, gamma ray and 2 MHz phase resistivity are the logging while drilling(LWD) parameters that significantly influence lithology identification. The comprehensive performance of the DFW-RF lithology identification model has been verified in the application of 3 wells in different areas. By comparing the prediction results of five typical lithology identification algorithms, the DFW-RF model has a higher lithology identification accuracy rate and F1 score. This model improves the identification accuracy of thin-layer lithology and is effective and feasible in different geological environments. The DFW-RF model plays a truly efficient role in the realtime intelligent identification of lithologic information in closed-loop drilling and has greater applicability, which is worthy of being widely used in logging interpretation.

关键词： Intelligent drilling Closed-loop drilling Lithology identification Random forest algorithm Feature extraction

Soft coarse-grained particle model for particle-fluid systems

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Particuology 2024年第1期84卷 178-193页

作者： Yanhao Ye Ji xu wei Ge State Key Laboratory of Multiphase Complex Systems Institute of Process EngineeringChinese Academy of SciencesBeijing100190China School of Chemical Engineering University of Chinese Academy of SciencesBeijing100049China Innovation Academy for Green Manufacture Chinese Academy of SciencesBeijing100190China

By modeling a group of neighboring real particles as a single coarse-grained particle(CGP),discrete particle method(DPM)is now capable of simulating industrial-scale particle-fluid ***,a systematic approach to determine the CGP properties and develop their interaction models is still lacking,which casts uncertainty on the predictivity of the *** this study,collisions between predefined particle groups are analyzed to construct kernel functions for modeling the CGPs and then the model parameters are determined by equating the statistical properties of the CGPs and the real particles in the physical process *** approach is implemented for homogeneous cooling of granular gas,then demonstrated effective in simulating experimental fluidized beds.

关键词： Coarse-grain(CG) Discrete particle method(DPM) Fluidized bed Multi-scale simulation

Hawking-Page transition and the dual relations of anti-de Sitter black holes surrounded by dark energy in general dimensions

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Communications in Theoretical Physics 2024年第7期76卷 94-104页

作者： Zhang Xin xu wei School of Mathematics and Physics China University of GeosciencesWuhan 430074China

Recently,a dual relation T_(0)(n+1)=T_(HP)(n)between the minimum temperature(T_(0)(n+1))black hole phase and the Hawking-Page transition(T_(HP)(n))black hole phase in two successive dimensions was introduced by wei et al(2020 ***.D10210411);this was reminiscent of the anti-de Sitter/conformal field theory(AdS/CFT)correspondence,as the Hawking-Page transition temperature could be treated as the temperature of the dual physical quantity on the boundary and the latter corresponds to that in the *** this paper,we discuss the Hawking-Page transition and the dual relations in Ads black holes surrounded by dark energy in general *** findings reveal the occurrence of the Hawking-Page transition between the thermal AdS radiation and thermodynamically stable large AdS black holes,in both the spacetime surrounded by phantom dark energy and the spacetime surrounded by quintessence dark *** discuss the effects of the phantom dark energy and quintessence dark energy on the Hawking-Page transition *** the dual relation in particular,it works well for the case of an AdS black holes surrounded by phantom dark *** the case of an Ads black hole surrounded by quintessence dark energy,the dual relation should be modified under an open assumption that the state parameter and the density parameter of the quintessence dark energy depend on the dimensions of the spacetime.

关键词： Hawking-Page transition dark energy black hole thermodynamics

An accurate and efficient space-time Galerkin spectral method for the subdiffusion equation

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Science China Mathematics 2024年第10期67卷 2387-2408页

作者： wei Zeng Chuanju xu School of Mathematical Sciences and Fujian Provincial Key Laboratory of Mathematical Modeling and High Performance Scientific Computing Xiamen UniversityXiamen 361005China

In this paper, we design and analyze a space-time spectral method for the subdiffusion ***, we are facing two difficulties. The first is that the solutions of this equation are usually singular near the initial time. Consequently, traditional high-order numerical methods in time are inefficient. The second obstacle is that the resulting system of the space-time spectral approach is usually large and time-consuming to solve. We aim at overcoming the first difficulty by proposing a novel approach in time, which is based on variable transformation techniques. Suitable ψ-fractional Sobolev spaces and a new variational framework are introduced to establish the well-posedness of the associated variational problem. This allows us to construct our space-time spectral method using a combination of temporal generalized Jacobi polynomials(GJPs) and spatial Legendre polynomials. For the second difficulty, we propose a fast algorithm to effectively solve the resulting linear system. The fast algorithm makes use of a matrix diagonalization in space and QZ decomposition in time. Our analysis and numerical experiments show that the proposed method is exponentially convergent with respect to the polynomial degrees in both space and time directions, even though the exact solution has very limited regularity.

关键词： subdiffusion equations variable transformation Ψ-Sobolev spaces well-posedness space-time Galerkin spectral method error estimate fast algorithm

Stable,intense supercontinuum light generation at 1 kHz by electric field assisted femtosecond laser filamentation in air

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Light(Science & Applications) 2024年第2期13卷 354-365页

作者： Yaoxiang Liu Fukang Yin tie-Jun Wang Yuxin Leng Ruxin Li Zhizhan xu See Leang Chin State Key Laboratory of High Field Laser Physics Shanghai Institute of Optics and Fine Mechanics and CAS Center for Excellence in Ultra-intense Laser ScienceChinese Academy of SciencesShanghaiChina Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijingChina Centre d’Optique Photonique et Laser(COPL)and Département de physiquede génie physique et d’optiqueUniversitéLavalQuébecQuébecCanada

Supercontinuum(SC)light source has advanced ultrafast laser spectroscopy in condensed matter science,biology,physics,and *** to the frequently used photonic crystal fibers and bulk materials,femtosecond laser filamentation in gases is damage-immune for supercontinuum generation.A bottleneck problem is the strong jitters from filament induced self-heating at kHz repetition rate *** demonstrated stable kHz supercontinuum generation directly in air with multiple mJ level pulse *** was achieved by applying an external DC electric field to the air plasma *** pointing jitters of the 1 kHz air filament induced SC light were reduced by more than 2 *** stabilized high repetition rate laser filament offers the opportunity for stable intense SC generation and its applications in air.

关键词： intense repetition light