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Grain-refining and strengthening mechanisms of bulk ultrafine grained CP-Ti processed by L-ECAP and MDF

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Journal of Materials Science & Technology 2021年第24期83卷 196-207页

作者： peng-cheng zhao Guang-Jian Yuan Run-Zi Wang Bo Guan Yun-Fei Jia Xian-cheng Zhang Shan-Tung Tu Key Laboratory of Pressure Systems and Safety Ministry of EducationSchool of Mechanical and Power EngineeringEast China University of Science and TechnologyShanghai200237China National Engineering Research Center for Magnesium Alloys Chongqing UniversityChongqing400044China

The microstructural evolution and mechanical properties of ultrafine-grained(UFG)CP-Ti after an innovative large-volume equal channel angular pressing(L-ECAP)and multi-directional forging(MDF)were systematically examined using monotonic tensile tests combined with transmission electron microscope(TEM)and electron backscatter diffraction(EBSD)*** refined and homogeneous microstructures were achieved after L-ECAP(8-pass and 12-pass)and MDF(2-cycle and 3-cycle),respectively,where the grain size distribution conformed to lognormal *** grain refinement of450℃L-ECAP is dominated by dynamic recrystallization(DRX)and dynamic recovery(DRV),while that of MDF is dominated by *** iron impurities promote recrystallization by pinning-induced dislocation accumulation so that DRX is prone to occur at iron segregation regions during *** monotonic tensile results show that the strain hardening rate of CP-Ti increases with the decrease of grain size,while the continuous strain hardening ability *** relationship between the average grain size and yield strength is in accordance with Hall-Petch ***,the individual strengthening mechanisms were quantitatively examined by the modified *** results indicate that the strengthening contribution of dislocation accumulation to yield strength is greater than that of grain refinement.

关键词： Equal channel angular pressing Multi-directional forging Ultrafine grain Recrystallization Strain hardening Hall-Petch relation

Spacelike Framed Curves with Lightlike Components and Singularities of Their Evolutes and Focal Surfaces in Minkowski 3-space

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Acta Mathematica Sinica,English Series 2024年第6期40卷 1521-1532页

作者： peng cheng LI Dong He PEI Xin zhao School of Mathematics and Statistics Northeast Normal UniversityChangchun 130024P.R.China Department of Mathematics Harbin Institute of TechnologyWeihai 264209P.R.China School of Mathematics and Statistics Qingdao UniversityQingdao 266071P.R.China

In this paper,we define the evolute and focal surface of a spacelike framed curve with lightlike components in Minkowski *** is a generalization of the previous results of regular spacelike curves,since singularities are allowed in the original spacelike curves studied by spacelike framed curves with lightlike ***,we show a new geometric invariant to characterise singularities of the focal ***,the classification theorem and recognition theorem for the singularities of the focal surface in generic are also given.

关键词： Evolutes focal surfaces spacelike framed curves singularities

Machining dynamics and chatters in micro-milling:A critical review on the state-of-the-art and future perspectives

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Chinese Journal of Aeronautics 2024年第7期37卷 59-80页

作者： Qingshun BAI peng WANG Kai cheng Liang zhao Yabo ZHANG School of Mechanical and Electrical Engineering Harbin Institute of TechnologyHarbin 150001China Department of Mechanical and Aerospace Engineering Brunel University LondonUxbridge UB83PHUK

Micro-milling technology is widely applied in micro manufacturing,particularly for the fabrication of miniature and micro ***,the chatters and machining dynamics related issues in micro-milling are often the main challenges restricting its machining quality and *** research works have rendered that the machining dynamics and chatters in micro-milling are more complex compared with the conventional macro-milling process,likely because of the size effect and rigidity of the micro-milling system including the tooling,workpiece,process variables,materials involved,and the high-speed milling machines,and further their collective dynamic ***,in this paper,the state of the art focusing on micro-milling chatters and dynamics related issues over the past years are comprehensively and critically reviewed to provide some insights for potential researchers and ***,typical applications and the problems caused by the machining dynamics and chatters in micro-milling have been put forward in this ***,the research on the underlying micro-cutting mechanics and dynamics,stability analysis,chatters detection,and chatter suppression are summarized ***,the underlying scientific and technological challenges are discussed particularly against typical precision engineering ***,the possible future directions and trends in research and development of micro-milling have been discussed.

关键词： Micro-milling Machining dynamics Micro-cutting mechanics Stability lobe diagram(SLD) Chatters suppression Digital twin

Partial flow blockage analysis of the hottest fuel assembly in SNCLFR-100 reactor core

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Nuclear Science and Techniques 2018年第1期29卷 110-117页

作者： Kang-Li Shi Shu-Zhou Li Xi-Lin Zhang peng-cheng zhao Hong-Li Chen School of Nuclear Science and Technology University of Science and Technology of China

In this paper, we perform an unprotected partial flow blockage analysis of the hottest fuel assembly in the core of the SNCLFR-100 reactor, a 100 MW_(th) modular natural circulation lead-cooled fast reactor, developed by University of Science and Technology of China. The flow blockage shall cause a degradation of the heat transfer between the fuel assembly and the coolant potentially,which can eventually result in the clad fusion. An analysis of core blockage accidents in a single assembly is of great significance for LFR. Such scenarios are investigated by using the best estimation code RELAP5. Reactivity feedback and axial power profile are considered. The crosssectional fraction of blockage, axial position of blockage,and blockage-developing time are discussed. The cladding material failure shall be the biggest challenge and shall be a considerable threat for integrity of the fuel assembly if the cross-sectional fraction of blockage is over 94%. The blockage-developing time only affects the accident progress. The consequence will be more serious if the axial position of a sudden blockage is closer to the core *** method of analysis procedure can also be applied to analyze similar transient behaviors of other fuel-type reactors.

关键词： Transient analysis Flow blockage LFR Natural circulation RELAP5 code

Analysis of destructive effect of Zn on carbon brick and way of Zn into carbon brick

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Journal of Iron and Steel Research International 2024年第6期31卷 1344-1354页

作者： peng-bo Liu Shu-sen cheng Yu-qing Xue Xiao-man cheng zhao Liu University of Science and Technology Beijing Beijing 100083China Ministry of Ironmaking Shangdong Taishan Steel Group Co.Ltd.Taian 271000ShandongChina

The service life of a blast furnace depends largely on the degree of damage to the carbon brick in the *** brick and ramming material in the hearth of a 1780 m3 blast furnace after shutdown were sampled and *** was found that the substances in the cracks of the carbon brick near and above the taphole were ZnO and Zn_(2)SiO_(4),whereas the substances in the cracks of the carbon brick below the taphole were *** reaction of Zn with CO,SiO_(2),and Fes generates ZnO,Zn_(2)SiO_(4),and ZnS,resulting in volume expansion,which is an important reason for the cracking of carbon ***,several obvious Zn vapor flow channels were found in the ramming material,through which Zn vapor could enter the carbon brick,causing damage to the carbon *** the compactness of the ramming material is beneficial to preventing Zn vapor from entering the carbon brick through the voids in the ramming material,reducing the destructive effect of Zn on the carbon brick and further extending the service life of the blast furnace.

关键词： Zn Blast furnace Carbon brick Ramming material Crack

Comparisons of Infrared Colors and Emission-line Intensities between Two types of Seyfert 2 Galaxies

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Chinese Journal of Astronomy and Astrophysics 2002年第5期2卷 408-418页

作者： Lin-peng cheng, Yong-Heng zhao and Jian-Yan WeiNational Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 National Astronomical Observatories CAS NAOC Beijing China

We study the relation between the infrared colors, [OIII] emission lines, gaseous absorbing column density (NH),and the detectability of the polarized (hidden) broad-line region (HBLR) in a large sample of 75 Seyfert 2 galaxies (Sy2s). From the indicators of star-formation activity, f60/f100 and LFIR/LB, we find some evidence that the Sy2s without HBLR show higher star-formation activities than those with HBLR, in agreement with previous prediction. Also, we confirm that the HBLR Sy2s tend to have a larger luminosity ratio of the core to the host galaxy, suggesting that the HBLR Sy2s display more powerful AGN activity. However, the level of obscuration found in previous papers is nearly indistinguishable between the two types of Sy2s. The results support the statement that the non-HBLR Sy2s, with a weaker core component and a stronger star-formation activity component, are intrinsically different from the HBLR Sy2s, which are Sy1 systems with a hidden powerful AGN core and a low star-formation activity. The indications are that the non-HBLR Sy2s might be at an earlier evolutionary phase than the HBLR Sy2s.

关键词： galaxies: active - galaxies: Seyfert - polarization - star formation

Reoxidation of liquid steel and evolution of inclusions during protective atmosphere electroslag remelting of Ce-containing heat-resistant stainless steel

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Journal of Iron and Steel Research International 2024年第8期31卷 1923-1935页

作者： Yu zhao cheng-bin Shi Shijun Wang peng Ren Jing Li State Key Laboratory of Advanced Metallurgy University of Science and Technology Beijing(USTB)Beijing 100083China

The evolution of Ce-containing inclusions and its correlation with the reoxidation of liquid steel during protective atmosphere electroslag remelting(ESR)of heat-resistant steel were *** reoxidation of liquid steel took place during the ESR,resulting in the oxygen pickup from 0.0014 to 0.0053 wt.%.The inclusions in the consumable electrode,liquid metal pool and remelted ingot are Ce_(2)O_(2)S and Ce_(2)O,inclusions *** inclusions in the remelted ingot are originated from three ways:(I)the original inclusions from the electrode;(Il)the newly formed Ce_(2)O_(2)S and Ce_(2)O_(3) inclusions in the liquid metal pool by reoxidation remaining still in remelted ingot;(IlI)the newly generated Ce2O2S and Ce_(2)O_(3) inclusions during cooling and solidification of liquid *** relative proportions of Ce_(2)O_(3) inclusions in liquid metal pool and remelted ingot are 41% and 76.5%,*** inclusions ranging from 2 to 5μm in the remelted ingot take up 55%,followed by the inclusions smaller than 2μm(43%of total inclusions).The number proportion of the Ce_(2)0,inclusions in the liquid metal pool which were removed by floating up into slag is 1.96×10-5%.

关键词： Non-metallic inclusion Electroslag remelting Rare earth cerium Reoxidation Inclusion evolution

HIF-1α signaling: Essential roles in tumorigenesis and implications in targeted therapies

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Genes & Diseases 2024年第1期11卷 234-251页

作者： Yan zhao cheng Xing Yating Deng Can Ye Hongling peng Department of Hematology The Second Xiangya HospitalCentral South UniversityChangshaHunan 410011China Hunan Key Laboratory of Tumor Models and Individualized Medicine The Second Xiangya HospitalCentral South UniversityChangshaHunan 410011China Hunan Engineering Research Center of Cell Immunotherapy for Hematopoietic Malignancies The Second Xiangya HospitalCentral South UniversityChangshaHunan 410011China

The hypoxic microenvironment is an essential characteristic of most malignant ***,hypoxia-inducible factor-1 alpha(HIF-1a)is a key regulatory factor of cellular adaptation to hypoxia,and many critical pathways are correlated with the biological activity of organisms via *** the intra-tumoral hypoxic environment,HIF-1αis highly expressed and contributes to the malignant progression of tumors,which in turn results in a poor prog-nosis in ***,it has been indicated that HiF-1αinvolves in various critical pro-cesses of life events and tumor development via regulating the expression of HiF-1a target genes,such as cell proliferation and apoptosis,angiogenesis,glucose metabolism,immune response,therapeutic resistance,*** from solid tumors,accumulating evidence has re-vealed that HiF-1αis also closely associated with the development and progression of hemato-logical malignancies,such as leukemia,lymphoma,and multiple *** inhibition of HiF-1a can facilitate an increased sensitivity of patients with malignancies to relevant ther-apeutic *** the review,we elaborated on the basic structure and biological functions of HIF-1a and summarized their current role in various *** is expected that they will have future potential fortargeted therapy.

关键词： Angiogenesis Hematological malignancies Hypoxia-inducible factor-1 alpha(HIF-1α) Immune escape Targeted therapy

Structured Multi-Head Attention Stock Index Prediction Method Based Adaptive Public Opinion Sentiment Vector

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Computers, Materials & Continua 2024年第1期78卷 1503-1523页

作者： cheng zhao Zhe peng Xuefeng Lan Yuefeng Cen Zuxin Wang School of Economics Zhejiang University of TechnologyHangzhouChina College of Management Zhejiang University of TechnologyHangzhouChina Informatization Office Zhejiang University of TechnologyHangzhouChina School of Information and Electronic Engineering Zhejiang University of Science&TechnologyHangzhouChina School of Economics and Management Universiti Putra MalaysiaDaerah PetalingNegeri SelangorMalaysia

The present study examines the impact of short-term public opinion sentiment on the secondary market,with a focus on the potential for such sentiment to cause dramatic stock price fluctuations and increase investment *** quantification of investment sentiment indicators and the persistent analysis of their impact has been a complex and significant area of *** this paper,a structured multi-head attention stock index prediction method based adaptive public opinion sentiment vector is *** proposedmethod utilizes an innovative approach to transform numerous investor comments on social platforms over time into public opinion sentiment vectors expressing complex *** then analyzes the continuous impact of these vectors on the market through the use of aggregating techniques and public opinion data via a structured multi-head attention *** experimental results demonstrate that the public opinion sentiment vector can provide more comprehensive feedback on market sentiment than traditional sentiment polarity ***,the multi-head attention mechanism is shown to improve prediction accuracy through attention convergence on each type of input information *** absolute percentage error(MAPE)of the proposedmethod is 0.463%,a reduction of 0.294% compared to the benchmark attention ***,the market backtesting results indicate that the return was 24.560%,an improvement of 8.202% compared to the benchmark *** results suggest that themarket trading strategy based on thismethod has the potential to improve trading profits.

关键词： Public opinion sentiment structured multi-head attention stock index prediction deep learning