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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 quality.Different solidification process of molten iron can be reflected by thermal analysis curves,and silicon is one of important elements affecting the solidification of molten iron.In 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 investigated.The 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 increase.The temperature at final solidification point TEShas little change.The 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 one.According 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 curves.The 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

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Effect of Cu content on microstructures and mechanical properties of ADI treated by twostep austempering process

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China Foundry 2019年第3期16卷 168-176页

作者： Peng-yue yi Er-jun Guo Li-ping Wang yi-cheng feng Chang-liang Wang School of Material Science and Engineering Harbin University of Science and Technology

The effect of Cu content on the microstructures and mechanical properties (yield strength, ultimate tensile strength, impact energy, fracture toughness) of austempering ductile iron (ADI) treated by two-step austempering process were investigated. High Cu content in nodular cast irons leads to a significant volume fraction of retained austenite in the iron after austempering treatment, but the carbon content of austenite decreases with the increasing of Cu content. Moreover, austenitic stability reaches its maximum when the Cu content is 1.4% and then drops rapidly with further increase of Cu. The ultimate tensile strength and yield strength of the ADI firstly increases and then decreases with increasing the Cu content. The elongation keeps constant at 6.5% as the Cu content increases from 0.2% to 1.4%, and then increases rapidly to 10.0% with further increase Cu content to 2.0%. Impact toughness is enhanced with Cu increasing at first, and reaches a maximum 122.9 J at 1.4% Cu, then decreases with the further increase of Cu. The fracture toughness of ADI shows a constant increase with the increase of Cu content. The influencing mechanism of Cu on austempered ductile iron (ADI) can be classified into two aspects. On the one hand, Cu dissolves into the matrix and functions as solid solution strengthening. On the other hand, Cu reduces solubility of C in austenite and contributes more stable retained austenite.

关键词： Cu-alloyed ADI two-step austempering process mechanical properties austenite stability

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Microstructure and mechanical properties of twostep Cu-alloyed ADI treated by different second step austempering temperatures and times

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China Foundry 2019年第5期16卷 342-351页

作者： Peng-yue yi Er-jun Guo Li-ping Wang yi-cheng feng Chang-liang Wang School of Material Science and Engineering Harbin University of Science and Technology

Austempering ductile iron (ADI) is an attractive material due to its excellent comprehensive mechanical properties. However, the deficit in elongation and toughness always threatens its security application. Two-step austempering process is an effective way to improve elongation and toughness simultaneously. In the present work, the influence of the amount, morphology and distribution of ferrite and austenite on mechanical properties of ADI under different second-step austempering parameters has been analyzed. Results show that the amount of austenite and its carbon content decrease with increasing of second-step temperature. Carbide begins to precipitate as second-step austempering temperature reaches 380 °C. These factors together influence the mechanical properties of two-step Cu-alloyed ADI. Impact energy and fracture toughness are strongly affected by second-step austempering temperature, and are dramatically decreased with increase of second-step austempering temperature. Elongation remains constant when the second-step temperature is below 360 °C, and then it is rapidly decreased with further increase of second-step temperature. Strength is slightly influenced by second-step temperature. Ferrite morphology is not influenced by second-step austempering duration, while blocky retained austenite size is slightly decreased with the increasing of second-step austempering time. The amount of retained austenite is decreased while the carbon content of retained austenite is increased with the extending of second-step austempering time. The substructure of austenite is transformed from dislocation to twin when second-step austempering time exceeds 60 min. Strength and elongation are improved slightly with extending of second-step time. Impact energy and fracture toughness initially decrease with the extending of second-step time, and then remain constant when the time is longer than 60 min. This is a result of austenite content decreasing and carbon content of austenite increasing. The second-step austempering time

关键词： two-step austempering process Cu-alloyed ADI microstructure mechanical properties fracture toughness

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Constitutive equation and hot processing maps of Al-5Ti-1B master alloy

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Rare Metals 2018年第8期37卷 668-674页

作者： Fu-Wei Kang Jie Zhou Zhi-Wei Wang Xue-Min Zhang yi-cheng feng Er-Jun Guo School of Materials Science and Engineering Harbin Universityof Science and Technology Harbin 150040 China Harbin Dong An Engine Group Corporation Ltd. Aviation Industry Corporation of China Harbin 150066 China

The isothermal compression tests of A1-5Ti- 1B master alloy were conducted on the thermal mechanical simulator Gleeble-1500D at the deformation temperature range of 300-450 ℃,the strain rate range of 0.01- 10.00 s^-l, and the engineering strain of 50 %. The effects of deformation temperatures and strain rates on the flow stress were analyzed by the true stress-true strain curves. The result indicates that the flow stress increases with the increase of strain rate, while it decreases with the increase of temperature. The hot deformation activation energy of A1-5Ti-IB master alloy is calculated to be 250.9 kJ.mol^-1, and the constitutive equation is established as ε=1.97 x lO^19[sinh（O.O15δ）^11.14exp（-250.9/RT）, and the validity of this constitutive equation is verified. Based on dynamic material model （DMM） criterion, the hot processing map of AI-5Ti-1B master alloy is obtained. The optimum hot extrusion conditions are determined as deformation temperature of 400℃ and strain rate of 1.00 s^-1, and the flow instability only appears at the temperature range of 300-340℃ at the base of the hot processing map.

关键词： Al-5Ti-1B master alloy Flow stress Constitutive equation Hot processing map

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Microstructure,mechanical properties and fracture behavior of a new WE43 alloy

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Rare Metals 2021年第8期40卷 2197-2205页

作者： Gui-Long Jia Li-Ping Wang yi-cheng feng Er-Jun Guo Yan-Hong Chen Chang-Liang Wang School of Materials Science and Engineering Harbin University of Science and TechnologyHarbin150040China

The microstructures,mechanical properties and fracture behaviors of a new WE43 alloy(Mg-4 Y-1.6 Nd-2 Sm-0.5 Zr)were investigated.The microstructure of the as-cast alloy includes a Mg matrix,Mg_(41)Sm_(5),Mg_(41)Nd_(5)and Mg_(24)Y_(5)eutectic phases,as well asβ-phase.After an optimal solution treatment,the eutectic phases are almost completely dissolved;only a few spots of blocky Mg-Y compounds remain at grain boundaries.After an aging treatment,a large amount ofβ’-phases are dispersed and precipitated at the grain interior,which provides good comprehensive mechanical properties of the alloy,particularly in the under-aged state.The tensile strength is up to290 MPa,the yield strength reaches 209 MPa,and the elongation is slightly improved.Furthermore,the fracture behaviors of the studied alloy in different states significantly differ.In addition,a comparison of mechanical properties of the new WE43,traditional WE43 and other modified WE43 alloys is presented.

关键词： Mg-Y-Nd-Sm-Zr Microstructure Mechanical properties Fracture behavior Heat treatment

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Coarse-fine joint target parameter estimation method based on AN-RSC in OFDM passive radar

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Journal of Systems Engineering and Electronics 2024年第2期35卷 339-349页

作者： WANG Chujun WAN Xianrong yi Jianxin cheng feng School of Electronic Information Wuhan UniversityWuhan 430072China

In this paper,we study the accuracy of delay-Doppler parameter estimation of targets in a passive radar using orthogonal frequency division multiplexing(OFDM)signal.A coarse-fine joint estimation method is proposed to achieve better estimation accuracy of target parameters without excessive computational burden.Firstly,the modulation symbol domain(MSD)method is used to roughly estimate the delay and Doppler of targets.Then,to obtain high-precision Doppler estimation,the atomic norm(AN)based on the multiple measurement vectors(MMV)model(MMV-AN)is used to manifest the signal sparsity in the continuous Doppler domain.At the same time,a reference signal compensation(RSC)method is presented to obtain highprecision delay estimation.Simulation results based on the OFDM signal show that the coarse-fine joint estimation method based on AN-RSC can obtain a more accurate estimation of target parameters compared with other algorithms.In addition,the proposed method also possesses computational advantages compared with the joint parameter estimation.

关键词： passive radar orthogonal frequency division multiplexing(OFDM)signal atomic norm(AN) parameter estimation

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Microstructure,wear and friction behavior of CoCrAITaY-xCNTs composite coatings deposited by laser-induction hybrid cladding

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Rare Metals 2024年第4期43卷 1815-1827页

作者： Sheng-feng Zhou Yu Long Yan-Liang yi cheng Deng Lian-Xi Hu Institute of Advanced Wear & Corrosion Resistant and Functional Materials Jinan University Wuhan National Laboratory for Optoelectronics (WNLO) Huazhong University of Science and Technology MOE Key Laboratory of New Processing Technology for NonFerrous Metals and Materials Guangxi Key Laboratory of Processing for Non-Ferrous Metals and Featured Materials Guangxi University School of Mechatronics Engineering Guangdong Polytechnic Normal University School of Materials Science and Engineering Harbin Institute of Technology

To improve the wear performance of CoCrAlYTa coating,part of the carbon nanotubes（CNTs）chemically reacted with Ta to form reinforcement phase（TaC）,while the other CNTs were retained as lubrication phase.Subsequently,the CoCrAlYTa-xCNTs（x=0,1,2,and 4;wt%） composite coatings were prepared by laserinduction hybrid cladding（LIHC）,and the microstructure and wear resistance of coatings were systematically analyzed.Results show that the coatings are mainly composed of TaC,y-（Co,Cr） and β-（Co,Cr）Al.As the CNTs content increases from 0 wt% to 4 wt%,the volume fraction of TaC increases from 13.11 vol% to 16.12 vol%.Meanwhile,the nano-hardness of γ-（Co,Cr） and β-（Co,Cr）Al are improved from 7.49 and 9.72 to 9.36 and 11.19 GPa,respectively.As a result,the microhardness of coating increases from HV536.25 to HV 738.16,the wear rate decreases from32.4 × 10-3to 6.1 × 10-3mg·m-1,and the average friction coefficient decreases from 0.55 to 0.44.The good wear performance of the coating is attributed to the formation of TaC and the existence of remained CNTs lubricant film.

关键词： Carbon nanotube MCrAlY coating Friction and wear performance Laser-induction hybrid cladding

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Diagnosis and therapy of tacrolimus toxicity in a liver transplant recipient during COVID-19 treatment

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Hepatobiliary & Pancreatic Diseases International 2024年第3期23卷 326-330页

作者： feng Zhu yi-Ming Wang Ming Ni Yuan Liang Jie-Hui Huang Xue-Hao Wang feng cheng Ling Lu Hepatobiliary Center The First Affiliated Hospital of Nanjing Medical UniversityKey Laboratory of Liver TransplantationChinese Academy of Medical SciencesNHC Key Laboratory of Liver TransplantationResearch Unit of Liver Transplantation and Transplant ImmunologyChinese Academy of Medical SciencesNanjing 210000China Department of Respiratory and Critical Care Medicine Wuxi Fifth People’s HospitalWuxi 214000China Jiangsu Key Laboratory of Cancer Biomarkers Prevention and TreatmentCollaborative Innovation Center for Cancer Personalized MedicineNanjing Medical UniversityNanjing 210000China

To the Editor:SARS-CoV-2,the pathogen responsible for the pandemic of coronavirus disease 2019(COVID-19),has had profound impacts on human health,and its antagonist Paxlovid is a commonly used treatment option[1].However,treatment selection for immunosuppressed patients,such as liver recipients,remains uncertain due to potential drug interactions and the risk of immunosuppressant dosage adjustment,which can cause liver injury[2].

关键词： dosage treatment antagonist

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Casual associations between blood metabolites and colon cancer

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World Journal of Gastrointestinal Oncology 2024年第5期16卷 1995-2005页

作者： Ke-Yue Hu yi-Quan cheng Zhi-Long Shi Fu-Peng Ren Gang-feng Xiao Department of Hematology and Oncology Ningbo No.2 HospitalNingbo 315000Zhejiang ProvinceChina

BACKGROUND Limited knowledge exists regarding the casual associations linking blood metabolites and the risk of developing colorectal cancer.AIM To investigate causal associations between blood metabolites and colon cancer.METHODS The study utilized a two-sample Mendelian randomization(MR)analysis to investigate the causal impact of 486 blood metabolites on colorectal cancer.The primary method of analysis used was the inverse variance weighted model.To further validate the results several sensitivity analyses were performed,including Cochran's Q test,MR-Egger intercept test,and MR robust adjusted profile score.These additional analyses were conducted to ensure the reliability and robustness of the findings.RESULTS After rigorous selection for genetic variation,486 blood metabolites were included in the MR analysis.We found Mannose[odds ratio(OR)=2.09(1.10-3.97),P=0.024],N-acetylglycine[OR=3.14(1.78-5.53),P=7.54×10^(-8)],X-11593-O-methylascorbate[OR=1.68(1.04-2.72),P=0.034],1-arachidonoylglycerophosphocholine[OR=4.23(2.51-7.12),P=6.35×10^(-8)]and 1-arachidonoylglycerophosphoethanolamine 4[OR=3.99(1.17-13.54),P=0.027]were positively causally associated with colorectal cancer,and we also found a negative causal relationship between Tyrosine[OR=0.08(0.01-0.63),P=0.014],Urate[OR=0.25(0.10-0.62),P=0.003],N-acetylglycine[0.73(0.54-0.98),P=0.033],X-12092[OR=0.89(0.81-0.99),P=0.028],Succinylcarnitine[OR=0.48(0.27-0.84),P=0.09]with colorectal cancer.A series of sensitivity analyses were performed to confirm the rigidity of the results.CONCLUSION This study showed a causal relationship between 10 blood metabolites and colorectal cancer,of which 5 blood metabolites were found to be causal for the development of colorectal cancer and were confirmed as risk factors.The other five blood metabolites are protective factors.

关键词： Metabolites Colon cancer Mendelian randomization Genome-wide association studies Casual

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Leflunomide: A versatile additive for defect reduction, enhanced optoelectronic properties and environmental stability of perovskite films

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Nano Research 2024年第4期17卷 2628-2637页

作者： Dingyue Sun Ming Peng Taijin Wang Longju yi Shizuo Zhang feng Liu Gary J.cheng The Institute of Technological Sciences Wuhan UniversityWuhan 430072China School of Power and Mechanical Engineering Wuhan UniversityWuhan 430072China School of Industrial Engineering Purdue UniversityWest LafayetteIN 47906USA

The development of perovskite photoelectric devices with excellent performance is largely dependent on the defects in the perovskite films.To address this issue,a specific drug,leflunomide(LF,C_(12)H_(9)F_(3)N_(2)O_(2)),was incorporated into the perovskite to reduce defects and improve its photoelectric properties.It is believed that the C=O bond on LF molecule can interact with the uncoordinated Pb2+of the perovskite,thereby reducing non-radiative recombination.This novel approach of incorporating LF into perovskite films has the potential to revolutionize the development of high-performance perovskite photoelectric devices.The trifluoromethyl functional(–CF_(3))group on LF can form a protective layer on the surface of the perovskite film,shielding it from water erosion.Moreover,LF can be utilized to alter the nucleation position of perovskite,thus minimizing the number of defects and optimizing the film quality.Consequently,the LF-doped perovskite film displays low trap density and high photoelectric performance.The LF-doped perovskite film showed a trap density of 8.28×10^(11),which is notably lower than the 2.04×10^(12) of the perovskite film without LF.The responsivity and detectivity of the LF-doped perovskite photodetector were 0.771 A/W and 2.81×10^(11) Jones,respectively,which are much higher than the 0.23 A/W and 1.06×10^(10) Jones of the LF-undoped perovskite photodetector.Meanwhile,the LF-doped photodetector maintained an initial photocurrent of 86%after 30 days of storage in air,indicating drastically increased environmental stability.This strongly suggests that LF is an effective additive for perovskites utilized in optoelectronic devices with high performance.

关键词： leflunomide additive engineering defect passivation perovskite

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