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Different thermal fatigue behaviors between gray cast iron and vermicular graphite cast iron

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China Foundry 2022年第3期19卷 245-252页

作者： gui-quan wang Zhong-li Liu Yan-xiang Li Xiang Chen School of Nuclear Equipment and Nuclear Engineering Yantai UniversityYantai 264005ShandongChina School of Materials Science and Engineering Tsinghua UniversityBeijing 100084China Key Laboratory for Advanced Materials Processing Technology Ministry of EducationTsinghua UniversityBeijing 100084China

The initiation and propagation of thermal fatigue cracks in gray cast iron and vemicular graphite cast iron were investigated by Uddeholm method to reveal the complex thermal fatigue behaviors of cast *** of thermal fatigue behaviors of gray cast iron and vemicular graphite cast iron were observed and *** is found that the observed differences are related to the combination of graphite morphology and the oxidization of *** oxidized matrix is observed in gray cast iron due to its large specific surface *** brittle oxidized matrix facilitates the propagation of microcracks along the oxidization *** contrast,the radial microcracks are formed in vermicular graphite at the edge of graphite due to fewer oxidization *** indicates that the thermal fatigue resistance of gray cast iron is dominated by graphite content and morphology while that of vermicular graphite cast iron strongly relates to the strength of the matrix.

关键词： thermal fatigue gray cast iron vermicular graphite cast iron oxidization cracking propagation

Effect of FeSi additive in dual-chamber sample cup on thermal analysis characteristic values and vermiculating rate of compacted graphite iron

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China Foundry 2024年第1期21卷 91-100页

作者： De-quan Shi Ze-yu Liu gui-li Gao Yi-cheng Feng School of Materials and Chemistry University of Shanghai for Science and TechnologyShanghai 200093China School of Materials Science and Chemical Engineering Harbin University of Science&TechnologyHarbin 150040China School of Mechanical and Energy Engineering Shanghai Technical Institute of Electronics and InformationShanghai 201411China

Thermal analysis plays a key role in the online inspection of molten iron *** solidification process of molten iron can be reflected by thermal analysis curves,and silicon is one of important elements affecting the solidification of molten *** this study,FeSi75 was added in one chamber of the dual-chamber sample cup,and the influences of FeSi75 additive on the characteristic values of thermal analysis curves and vermiculating rate were *** results show that with the increase of FeSi75,the start temperature of austenite formation TALfirstly decreases and then increases,but the start temperature of eutectic growth TSEF,the lowest eutectic temperature TEU,temperature at maximum eutectic reaction rate TEM,and highest eutectic temperature TERkeep always an *** temperature at final solidification point TEShas little *** FeSi75 additive has different influences on the vermiculating rate of molten iron with different vermiculation,and the vermiculating rate increases for lower vermiculation molten iron while decreases for higher *** to the thermal analysis curves obtained by a dual-chamber sample cup with 0.30wt.%FeSi75 additive in one chamber,the vermiculating rate of molten iron can be evaluated by comparing the characteristic values of these *** time differenceΔtERcorresponding to the highest eutectic temperature TERhas a closer relationship with the vermiculating rate,and a parabolic regression curve between the time differenceΔtERand vermiculating rateηhas been obtained within the range of 65%to 95%,which is suitable for the qualified melt.

关键词： FeSi75 additive characteristic value vermiculating rate thermal analysis compacted graphite iron

Fuzzy neural network analysis on gray cast iron with high tensile strength and thermal conductivity

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China Foundry 2019年第3期16卷 190-197页

作者： gui-quan wang Xiang Chen Yan-xiang Li School of Materials Science and Engineering Tsinghua University Beijing 100084 China Key Laboratory for Advanced Materials Processing Technology Ministry of Education Beijing 100084 China

To develop a high performance gray cast iron with high tensile strength and thermal conductivity, multivariable analysis of microstructural effects on properties of gray cast iron was performed. The concerned parameters consisted of graphite content, maximum graphite length, primary dendrite percentage and microhardness of the matrix. Under the superposed influence of various parameters, the relationships between thermal conductivity and structural characteristics become irregular, as well as the effects of graphite length on the strength. An adaptive neuro-fuzzy inference system was built to link the parameters and properties. A sensitivity test was then performed to rank the relative impact of parameters. It was found that the dominant parameter for tensile strength is graphite content, while the most relative parameter for thermal conductivity is maximum graphite length. The most effective method to simultaneously improve the tensile and thermal conductivity of gray cast iron is to reduce the carbon equivalent and increase the length of graphite flakes.

关键词： high performance gray cast iron fuzzy neural network tensile strength thermal conductivity

A survey on facial image deblurring

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Computational Visual Media 2024年第1期10卷 3-25页

作者： Bingnan wang Fanjiang Xu quan Zheng Institute of Software Chinese Academy of SciencesBeijing100190China University of Chinese Academy of Sciences Beijing100049China

When a facial image is blurred,it significantly affects high-level vision tasks such as face *** purpose of facial image deblurring is to recover a clear image from a blurry input image,which can improve the recognition accuracy,***,general deblurring methods do not perform well on facial ***,some face deblurring methods have been proposed to improve performance by adding semantic or structural information as specific priors according to the characteristics of the facial *** this paper,we survey and summarize recently published methods for facial image deblurring,most of which are based on deep ***,we provide a brief introduction to the modeling of image ***,we summarize face deblurring methods into two categories:model-based methods and deep learning-based ***,we summarize the datasets,loss functions,and performance evaluation metrics commonly used in the neural network training *** show the performance of classical methods on these datasets and metrics and provide a brief discussion on the differences between model-based and learning-based ***,we discuss the current challenges and possible future research directions.

关键词： facial image deblurring model-based deep learning-based semantic or structural prior

Strong shock propagation for the finite-source circular blast in a confined domain

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Applied Mathematics and Mechanics(English Edition) 2024年第6期45卷 1071-1084页

作者： Qihang MA Kaileong CHONG Bofu wang quan ZHOU Shanghai Key Laboratory of Mechanics in Energy Engineering Shanghai Institute of Applied Mathematics and MechanicsSchool of Mechanics and Engineering ScienceShanghai UniversityShanghai 200072China Shanghai Institute of Aircraft Mechanics and Control Shanghai 200092China

The circular explosion wave produced by the abrupt discharge of gas from a high-temperature heat source serves as a crucial model for addressing explosion phenomena in compressible *** reflection of the primary shock and its propagation within a confined domain are studied both theoretically and numerically in this *** the assumption of strong shock,the scaling law governing propagation of the main shock is *** dimensionless frequency of reflected shock propagation is associated with the confined *** numerical simulation for the circular explosion problem in a confined domain is performed for *** the influence of confinement,the principal shock wave systematically undergoes reflection within the domain until it weakens,leading to the non-monotonic attenuation of kinetic energy in the explosion fireball and periodic oscillations of the fireball volume with a certain *** simulation results indicate that the frequency of kinetic energy attenuation and the volume oscillation of the explosive fireball align consistently with the scaling law.

关键词： explosion confinement main shock frequency

Casting process design and practice for coolant pump impeller in AP1000 nuclear power station

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China Foundry 2020年第2期17卷 173-177页

作者： Ping Zhao Zhong-li Liu gui-quan wang Peng Liu College of Materials Science and Engineering Qingdao University of Science&TechnologyQingdao 266044China School of Nuclear Equipment and Nuclear Engineering Yantai UniversityYantai 264005China Institute of Metal Research Chinese Academy of ScienceShenyang 110016China

The coolant pump impeller casting is the only rotating component in the nuclear island of an AP1000 nuclear power station, and is required to have a 60-year service time, which requires advanced materials and processing technologies to guarantee. In this paper, the casting process was studied, designed and modified by means of numerical simulation. The gating system was distributed symmetrically and the runner diameter was a little bigger for avoiding sand wash and turbulence;the feeding system focused on the solution of blades feeding, as some parts of which should reach Severity Level 1 radioactive testing standard. Therefore, upper and lower plates cooperating with chillers acted as feeding method besides additional 2-3 times thickness;in addition, lowering sand core strength, decreasing pouring temperature and increasing dimension allowance would be adopted to avoid crack defects. Finally, the pilot impeller was cast. The results show that the casting process design is reasonable, as the liquid rises very smoothly when pouring, and no volume defects are found by means of 100% radioactive testing. Based on this casting process, 16 coolant pump impellers have been successfully produced and delivered to customers.

关键词： AP1000 coolant pump impeller casting process

Effects of alloying elements on thermal conductivity of pearlitic gray cast iron

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Journal of Iron and Steel Research(International) 2019年第9期26卷 1022-1030页

作者： gui-quan wang Xiang Chen Yan-xiang Li Yuan Liu Hua-wei Zhang Zhong-li Liu School of Materials Science and Engineering Tsinghua UniversityBeijing 100084China School of Nuclear Equipment and Nuclear Engineering Yantai UniversityYantai 264005ShandongChina Key Laboratory for Advanced Materials Processing Technology Tsinghua UniversityBeijing 100084China

A quantitative model is proposed to describe the thermal conductivity of alloyed pearlitic gray cast iron. The model is built by combining the computational thermodynamics and effective medium theory. The volume fractions and concentrations of precipitated phases in as-cast structure are estimated in consideration of partial and para-equilibrium. The conductivity of alloyed ferrite is calculated, taking into account the electronic and vibrational contributions of alloying elements. The model provides a good agreement with microstructure analysis and measured thermal conductivity. The influence of common alloying elements was discussed from the viewpoint of precipitation of phases and scattering of alloying atoms. This model can also be used as a numerical tool for designing the pearlitic gray cast irons with high thermal conductivity and high tensile strength.

关键词： Thermal conductivity Thermodynamic model Gray cast iron Alloying element

Rheological Behaviors of Polymers with Nanoparticles Tethered at Each End

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Chinese Journal of Polymer Science 2024年第3期42卷 400-406,I0009页

作者： Song-Qi Zhang Wen-Qing wang Jia-Ping Lin Li-quan wang Shanghai Key Laboratory of Advanced Polymeric Materials Key Laboratory for Ultrafine Materials of Ministry of EducationSchool of Materials Science and EngineeringEast China University of Science and TechnologyShanghai 200237China

The polymer with nanoparticles tethered at each end is a unique model for unraveling the effect of chain ends on the polymer dynamics. We investigated the rheological behavior of this kind of polymer by using nonequilibrium molecular dynamics simulation. The effect of polymer lengths and nanoparticle radii on the complex moduli and viscosity was examined. The dependence of complex moduli on the frequency becomes less pronounced as the polymer is short or the nanoparticle is large. The shear thinning behavior was revealed for these systems, and the scaling exponent of complex viscosity with respect to the frequency was found to change from-1/2 to-3/4 as the polymer shortens or the nanoparticle enlarges. The rheological behavior was further explained by analyzing the mean square distance of nanoparticles. The simulation results were compared with the existing experimental finding, showing an agreement. The work provides information for understanding the chain end effect on polymer rheology.

关键词： Polymer rheology Modulus Viscosity Molecular dynamics

Association between luteinizing hormone level decrease on the triggering day and pregnancy outcome for in vitro fertilization/intracytoplasmic sperm injection patients following gonadotropin-releasing hormone antagonist protocol: a retrospective cohor

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生殖与发育医学(英文) 2024年第1期08卷 8-17页

作者： Li Qing-Fang Tang Min-Yue wang gui-quan Chen Xi-Jing Feng Guo-Fang Zhu Yi-Min Women’s Hospital School of Medicine 3. Zhejiang University 4. 1 Xueshi Road 5. Hangzhou 310006 6. China

Objective: Optimal luteinizing hormone (LH) levels forin vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) patients following the gonadotropin-releasing hormone (GnRH) antagonist protocol remain controversial. This study aimed to estimate the association between serum LH levels on the triggering day (LHLOT) and clinical pregnancy outcomes in IVF/ICSI patients following the GnRH antagonist ***: We enrolled 4743 IVF/ICSI cycles using flexible or fixed GnRH antagonist protocols between January 2017 and June 2021. The patients were stratified into four groups according to the LHLOT quartiles (Q1–Q4). Each group was further divided into two subgroups according to the median basal LH/LHLOT. The main outcomes were clinical pregnancy, birth, and miscarriage rates. Secondary outcomes were oocyte yield, number of MII, fertilized oocytes (2PN), and high-quality ***: Serum LHLOT levels were negatively correlated with oocyte yield and the numbers of MII, 2PN, and high-quality embryos. Reproductive outcomes were compared among the different quartiles and subgroups. The absolute difference in the clinical pregnancy rates between the Q4 and Q1 groups was 6.4% (47.2%vs. 40.8%,P 3.04 and ≤3.04 were 32.7% and 48.6% (P 2.14 and ≤2.14 were 50.2% and 41.9%, respectively (P <0.05). The greater the decrease in LH levels, the lower the oocyte maturation rate across all ***: According to the LHLOT quartiles, the Q1 of serum LHLOT <1.43 IU/L may result in a higher number of oocytes but reduced oocyte maturation and lower clinical pregnancy rates. A decrease in LH levels by approximately 2.14 to 3.04 times compared to basal LH levels may lead to higher clinical pregnancy rates in IVF/ICSI patients following the GnRH antagonist protocol.

关键词： GnRH antagonist IVF/ICSI Luteinizing hormone Ovarian stimulation Reproductive outcomes