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Effect of directional solidification process on microstructure and stress rupture property of a hot corrosion resistant single crystal superalloy

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China Foundry 2019年第1期16卷 8-13页

作者： Liang Luo Cheng-bo Xiao Jing-yang Chen Qing Li sheng-long dai Science and Technology on Advanced High Temperature Structural Materials Laboratory Beijing Institute of Aeronautical MaterialsBeijing 100095China

The influences of different directional solidification processes, i.e., the high rate solidification(HRS) and liquid metal cooling(LMC), on microstructure and stress rupture property of DD488 alloy were investigated. The DD488 alloy was directional solidified by both HRS and LMC processes. The microstructure and stress rupture properties at 980 ℃/250 MPa were investigated by using optical microscopy(OM), scanning electron microscopy(SEM), electron microprobe analyzer(EPMA), transmission electron microscopy(TEM) and stress rupture testing. The results indicated that the LMC process refined the primary dendrite arm and decreased the microporosity volume fraction and solidification segregations of Cr and Co in as-cast DD488 alloy. After standard heat treatment of 1,260 ℃/4 h, AC(air cooling) + 1,080 ℃/4 h, AC + 870 ℃/24 h, AC, the γ′ morphology in LMC alloy was more cuboidal than that in HRS alloy, and the γ′ volume fraction of LMC alloy was higher than that of HRS alloy. The stress rupture life at 980 ℃/250 MPa of HRS alloy was 76.8 h, and it increased to 110.0 h in LMC al oy. The LMC process increased the stress rupture life due to the higher γ′ volume fraction, more perfect rafting structure and finer interfacial dislocation networks.

关键词： DD488 superalloy liquid metal cooling high rate solidification microstructure property

Effect of pressurizing speed on filling behavior of gradual expansion structure in low pressure casting of ZL205A alloy

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China Foundry 2018年第4期15卷 276-282页

作者： Shan-guang Liu Chuan-biao Luo Guo-ai Li Wen-lin Gao Zheng Lu sheng-long dai Beijing Institute of Aeronautical Materials Beijing 100095China

The mold filling behavior of gradual expansion structure in low pressure casting was studied by two phase flow model using the Volume of Fluid method, and was verified by water simulation with a Plexiglas mold. To get smooth mold filling process and provide a guide for the pressurizing speed design in the producing practice, the mathematical model with the pressurizing speed, expansion angle and height of the gradual expansion structure was established. For validation experiments, ZL205 A alloy castings were produced under two different pressurizing speeds. Weibull probability plots were used to assess the fracture mechanisms under different pressurizing speeds. Mechanical properties of ZL205 A alloy were applied to assess the entrainment of oxide film. The results show that the filling process of a gradual expansion structure in a low pressure casting can be divided into the spreading stage and filling stage by gate velocity. The gate velocity continues to increase in the gradual expansion structure, and increases with the increase of pressurizing speed or expansion angle. Under the effect of the falling fluid raised by the jet flow along the sidewall, the fluid velocity decreases in the jet zone from ingate to free surface. As such, oxide film entrainment does not occur when the gate velocity is greater than the critical velocity, andthe gate velocity no longer reflects the real state of the free surface. The scatter of the mechanical properties is strongly affected by the entrainment of oxide films.

关键词： low pressure casting two phase flow water simulation oxide film ZL205A alloy

Analysis of PAX6 gene in a Chinese aniridia family

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Chinese Medical Journal 2006年第16期119卷 1400-1402页

作者： ZHU Hai-yan WU Ling-qian PAN Qian LIANG De-sheng long Zhi-gao dai He-ping XIA Kun XIA Jia-hui National Laboratory of Medical Genetics Xiangya Hospital Central South University Changsha 410078 China

Aniridia is a dominantly inherited eye anomaly characterized by the near or complete absence of the iris with an incidence of approximately 1：80 000.1 Other ocular complications include glaucoma, cataract, and optic nerve hypoplasia. Aniridia can occur by itself, showing an autosomal dominant inheritance, or as part of the WAGR syndrome （Wilm＇s tumor, aniridia, genitourinary abnormalities, and mental retardation）.2 The PAX6 gene, a transcriptional regulator, is of high homology in many kinds of animal, which involves in ocular morphogenesis3 and responsible for aniridia.＂ It is located on chromosome 11p13 and consists of 14 exons with the initiation codon in exon 4 and the termination codon in exon 13. The PAX6 protein has an unusual structure with two DNA-binding domains,

关键词： aniridia PAX6 frameshift mutation

Approach from the laboratory to the field: New strategies in the control of mosquito-borne infectious diseases

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Science China Life Sciences 2025年第1期68卷 303-305页

作者： Ziqian Xu Lianpan dai Jun Liu National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases (NITFID) National Institute for Viral Disease Control and PreventionChinese Center for Disease Control and Prevention CAS Key Laboratory of Pathogen Microbiology and Immunology Institute of MicrobiologyChinese Academy of Sciences

Vector-borne viruses, transmitted among humans and animal hosts through bites of vectors such as mosquitoes and ticks,pose a great and ongoing threat to public health and biosafety(Yang et al., 2022).Among them, dengue virus-induced epidemics, have dramatically increased worldwide in recent decades. The report released by the World Health Organization(WHO) at the end of 2023 showed that dengue epidemic globally surged in2023, with the number of reported cases nearing a historical peak.

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Glutamatergic CYLD deletion leads to aberrant excitatory activity in the basolateral amygdala:association with enhanced cued fear expression

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Neural Regeneration Research 2025年第11期20卷 3259-3272页

作者： Huidong Li Faqin Li Zhaoyi Chen Erwen Wu Xiaoxi dai Danni Li Haojie An Shiyi Zeng Chunyan Wang Li Yang Cheng long School of Life Sciences South China Normal UniversityGuangzhouGuangdong ProvinceChina School of Life Sciences Guangzhou UniversityGuangzhouGuangdong ProvinceChina Guangdong Provincial Key Laboratory of Major Obstetric Diseases The Third Affiliated Hospital of Guangzhou Medical UniversityGuangzhouGuangdong ProvinceChina South China Normal University-Panyu Central Hospital Joint Laboratory of Translational Medical Research Panyu Central HospitalGuangzhouGuangdong ProvinceChina

Neuronal activity,synaptic transmission,and molecular changes in the basolateral amygdala play critical roles in fear ***(CYLD)is a deubiquitinase that negatively regulates the nuclear factor kappa-B *** is well studied in non-neuronal cells,yet underinvestigated in the brain,where it is highly *** studies have shown involvement of CYLD in the remodeling of glutamatergic synapses,neuroinflammation,fear memory,and anxiety-and autism-like ***,the precise role of CYLD in glutamatergic neurons is largely ***,we first proposed involvement of CYLD in cued fear *** next constructed transgenic model mice with specific deletion of Cyld from glutamatergic *** results show that glutamatergic CYLD deficiency exaggerated the expression of cued fear in only male ***,loss of CYLD in glutamatergic neurons resulted in enhanced neuronal activation,impaired excitatory synaptic transmission,and altered levels of glutamate receptors accompanied by over-activation of microglia in the basolateral amygdala of male ***,our study suggests a critical role of glutamatergic CYLD in maintaining normal neuronal,synaptic,and microglial *** may contribute,at least in part,to cued fear expression.

关键词： basolateral amygdala cued fear expression cylindromatosis deubiquitinase glutamate receptor 1 glutamatergic neuron microglial activation N-methyl-D-aspartate receptor 1 neuronal activation synaptic transmission

Emerging trends in the selective production of value-added aromatics

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Science China Chemistry 2025年第1期68卷 15-20页

作者： Yuchao Wu Houliang dai Weisheng Yang Yaxing Li Lichen Liu Petrochemical Research Institute Company Limited China National Petroleum Corporation Engineering Research Center of Advanced Rare Earth Materials Department of Chemistry Tsinghua University

1 Introduction Aromatics (mainly benzene, toluene, and xylenes, BTX) are essential intermediates in the chemical industry. They are employed in the synthesis of a broad spectrum of chemicals and materials, e.g., various polymers, plastics, resins, solvents, dyes, pharmaceuticals [1]. The manufacturing pathway of BTX mainly includes petroleum reforming of naphtha, coal-to-aromatics, methanol-to-aromatics [2].

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Research status and prospects of the fractal analysis of metal material surfaces and interfaces

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International Journal of Minerals,Metallurgy and Materials 2025年第1期32卷 20-38页

作者： Qinjin dai Xuefeng Liu Xin Ma Shaojie Tian Qinghe Cui Beijing Advanced Innovation Center for Materials Genome Engineering University of Science and Technology BeijingBeijing 100083China Beijing Laboratory of Metallic Materials and Processing for Modern Transportation University of Science and Technology BeijingBeijing 100083China Laboratory for Advanced Materials Processing of Ministry of Education University of Science and Technology BeijingBeijing 100083China School of Mechanical and Electrical Engineering Xinjiang Institute of EngineeringUrumqi 830023China

As a mathematical analysis method,fractal analysis can be used to quantitatively describe irregular shapes with self-similar or self-affine *** analysis has been used to characterize the shapes of metal materials at various scales and *** methods make it difficult to quantitatively describe the relationship between the regular characteristics and properties of metal material surfaces and ***,fractal analysis can be used to quantitatively describe the shape characteristics of metal materials and to establish the quantitative relationships between the shape characteristics and various properties of metal *** the perspective of two-dimensional planes and three-dimensional curved surfaces,this paper reviews the current research status of the fractal analysis of metal precipitate interfaces,metal grain boundary interfaces,metal-deposited film surfaces,metal fracture surfaces,metal machined surfaces,and metal wear *** relationship between the fractal dimensions and properties of metal material surfaces and interfaces is *** from three perspectives of fractal analysis,namely,research scope,image acquisition methods,and calculation methods,this paper identifies the direction of research on fractal analysis of metal material surfaces and interfaces that need to be *** is believed that revealing the deep influence mechanism between the fractal dimensions and properties of metal material surfaces and interfaces will be the key research direction of the fractal analysis of metal materials in the future.

关键词： metal material surfaces and interfaces fractal analysis fractal dimension homogeneity

A Multi-Objective Particle Swarm Optimization Algorithm Based on Decomposition and Multi-Selection Strategy

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Computers, Materials & Continua 2025年第1期82卷 997-1026页

作者： Li Ma Cai dai Xingsi Xue Cheng Peng School of Computer Science Shaanxi Normal UniversityXi’an710119China Fujian Provincial Key Laboratory of Big Data Mining and Applications Fujian University of TechnologyFuzhou350118China Information Construction and Management Center and Institute of Artificial Intelligence and Educational New Productivity Ningxia Normal UniversityGuyuan756099China

The multi-objective particle swarm optimization algorithm(MOPSO)is widely used to solve multi-objective optimization *** the article,amulti-objective particle swarm optimization algorithmbased on decomposition and multi-selection strategy is proposed to improve the search ***,two update strategies based on decomposition are used to update the evolving population and external archive,***,a multiselection strategy is *** first strategy is for the subspace without a non-dominated *** the neighbor particles,the particle with the smallest penalty-based boundary intersection value is selected as the global optimal solution and the particle far away fromthe search particle and the global optimal solution is selected as the personal optimal solution to enhance global *** second strategy is for the subspace with a non-dominated *** the neighbor particles,two particles are randomly selected,one as the global optimal solution and the other as the personal optimal solution,to enhance local *** third strategy is for Pareto optimal front(PF)discontinuity,which is identified by the cumulative number of iterations of the subspace without non-dominated *** the subsequent iteration,a new probability distribution is used to select from the remaining subspaces to ***,an adaptive inertia weight update strategy based on the dominated degree is designed to further improve the search ***,the proposed algorithmis compared with fivemulti-objective particle swarm optimization algorithms and five multi-objective evolutionary algorithms on 22 test *** results show that the proposed algorithm has better performance.

关键词： Multi-objective optimization multi-objective particle swarm optimization decomposition multi-selection strategy

退火温度对多向锻造Ti-6Al-4V合金显微组织演变和拉伸行为的影响

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Transactions of Nonferrous Metals Society of China 2024年第6期34卷 1864-1877页

作者：刘石双蔡建明周毅曹京霞张旺峰戴圣龙黄旭曹春晓中国航发北京航空材料研究院先进钛合金重点实验室北京100095

为调节Ti−6Al−4V锻件显微组织和力学性能,进行一系列退火处理。结果表明:锻态和退火态组织均呈现由等轴初生α相(αp)和转变β相(βt)组成的双态组织。随着退火温度的升高,次生α相(αs)从β相中析出。组织中没有明显的织构,晶体取向均... 详细信息

为调节Ti−6Al−4V锻件显微组织和力学性能,进行一系列退火处理。结果表明:锻态和退火态组织均呈现由等轴初生α相(αp)和转变β相(βt)组成的双态组织。随着退火温度的升高,次生α相(αs)从β相中析出。组织中没有明显的织构,晶体取向均匀分布。同时,强度呈先增大后减小的变化趋势,而塑性没有明显的变化。在860℃退火处理时,由于析出的细小αs相含量较高,合金具有强度和塑性的良好匹配。所有断口表面均包含大量韧窝,为典型的韧性断裂特征。在断口附近发现微裂纹、微孔洞和扭结αp/αl相(等轴αp相和片层α相)特征。

关键词： Ti−6Al−4V锻件退火温度显微组织演变次生α相拉伸性能韧性断裂