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06Cr23Ni13不锈钢的热压缩本构方程及热加工图

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材料热处理学报 2024年第1期45卷 193-199,208页

作者：叶梦元李俊琛权伟李尚霖杜小平西安汉唐分析检测有限公司陕西西安710200 兰州理工大学材料科学与工程学院甘肃兰州730050

利用Gleeble-3500热模拟试验机研究了06Cr23Ni13不锈钢在变形温度为850~1250℃及应变速率为0.01~10 s-1条件下的热变形软化行为。结果表明:当应变速率相同时,随着变形温度的升高,06Cr23Ni13不锈钢的流变应力减小;而当变形温度相同时,流... 详细信息

利用Gleeble-3500热模拟试验机研究了06Cr23Ni13不锈钢在变形温度为850~1250℃及应变速率为0.01~10 s-1条件下的热变形软化行为。结果表明:当应变速率相同时,随着变形温度的升高,06Cr23Ni13不锈钢的流变应力减小;而当变形温度相同时,流变应力值随着应变速率的增大而增大。根据Arrhenius模型构建并验证了06Cr23Ni13不锈钢的本构方程。基于动态材料模型理论绘制了06Cr23Ni13不锈钢在大变形量(ε=0.6)下的热加工图。由06Cr23Ni13不锈钢的热加工图可知在变形温度为1100~1250℃、应变速率为0.01~0.05 s-1的高温低应变区域内,能量耗散率η值可高达0.37~0.44,属于易加工区域,是最佳的热加工窗口。

关键词： 06Cr23Ni13不锈钢热压缩流变应力本构方程热加工图

低价锆氧化物Zr_(3)O的结构、热力学和弹性性质第一性原理研究

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Transactions of Nonferrous Metals Society of China 2024年第3期34卷 952-965页

作者：周虹伶陈莉君杨晓玲刘许旸孙超栾佰峰重庆大学材料科学与工程学院轻合金材料国际合作联合实验室沈阳材料科学国家研究中心重庆400044 重庆大学航空航天学院重庆400044 中国核动力研究设计院反应堆燃料及材料重点实验室成都610213 重庆大学机械传动国家重点实验室重庆400044

采用第一性原理系统地研究3种Zr_(3)O晶形(空间群分别为R3c(斜方六面体)、R32(斜方六面体)和P6322(六面体))的晶格动力学及其与温度相关的热力学和力学性质。计算得到的3种Zr_(3)O晶形的晶体结构参数与实验结果一致。此外,证明3种Zr_(3)... 详细信息

采用第一性原理系统地研究3种Zr_(3)O晶形(空间群分别为R3c(斜方六面体)、R32(斜方六面体)和P6322(六面体))的晶格动力学及其与温度相关的热力学和力学性质。计算得到的3种Zr_(3)O晶形的晶体结构参数与实验结果一致。此外,证明3种Zr_(3)O结构在动力学和热力学上均具有稳定性。获得了3种Zr_(3)O晶形在0~1500 K温度范围内的熵、焓、吉布斯自由能、比热容、热膨胀系数和弹性模量等性质。发现3种Zr_(3)O晶形在0K时的相对稳定性顺序为Zr_(3)O(R3c)>Zr_(3)O(R32)>Zr_(3)O(P6_(3)22);然而,在50 K时Zr_(3)O(R3c)转变成Zr_(3)O(R32),在540K时转变为Zr_(3)O(P6_(3)22)。相较于其他2种Zr_(3)O相,Zr_(3)O(R32)表现出更优越的力学性能。

关键词：第一性原理 Zr_(3)O 晶格动力学热力学性质弹性模量

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选区激光熔化430不锈钢成形工艺优化

材料热处理学报 2024年第2期45卷 112-119页

作者：卢康明李俊琛赵梦雨方政予程煜刚兰州理工大学材料科学与工程学院甘肃兰州730050 有色金属先进加工与再利用国家重点实验室甘肃兰州730050

研究了选区激光熔化(SLM)430不锈钢线-面-体的成形质量与工艺参数之间的关系。设计了单熔道、多道搭接以及块体成形试验,分析了SLM过程中缺陷形成的原因,以致密度为评价指标,确定SLM430不锈钢的最佳成形参数。结果表明:高功率低扫描速... 详细信息

研究了选区激光熔化(SLM)430不锈钢线-面-体的成形质量与工艺参数之间的关系。设计了单熔道、多道搭接以及块体成形试验,分析了SLM过程中缺陷形成的原因,以致密度为评价指标,确定SLM430不锈钢的最佳成形参数。结果表明:高功率低扫描速度有利于获得连续均匀的单熔道形貌,当激光功率为200 W、扫描速度为800 mm/s时,熔道宽度分布均匀。多道搭接的结果显示表面粗糙度随扫描间距的增加先降低后升高,扫描间距为0.08 mm时粗糙度最小,为3.88μm,表面成形质量最佳。通过正交试验分析,发现3种因素对块体成形件相对致密度影响的显著性排序为:扫描速度>激光功率>扫描间距;相对致密度随扫描速度的增大而减小;随着激光功率和扫描间距的增加,相对致密度呈现先升高后降低的趋势;最终确定SLM 430不锈钢的最佳成形工艺参数组合为激光功率200 W、扫描速度600 mm/s、扫描间距0.08 mm,该参数下成形件相对致密度达99.56%。

关键词： 430不锈钢选区激光熔化(SLM) 单熔道多道搭接工艺优化

Vision-based survey method for extraordinary loads on buildings

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Frontiers of Structural and Civil Engineering 2024年第6期18卷 815-831页

作者： Yang li jun chen Pengcheng WANG College of Civil Engineering Tongji UniversityShanghai 200092China China United Engineering Co.Ltd. Hangzhou 310052China State Key Laboratory of Disaster Reduction in Civil Engineering Tongji UniversityShanghai 200092China Shanghai Key Laboratory of Engineering Structure Safety Shanghai Research Institute of Building Sciences Co.Ltd.Shanghai 200032China

The statistical modeling of extraordinary loads on buildings has been stagnant for decades due to the laborious and error-prone nature of existing survey methods,such as questionnaires and verbal *** study proposes a new vision-based survey method for collecting extraordinary load data by automatically analyzing surveillance *** this purpose,a crowd head tracking framework is developed that integrates crowd head detection and reidentification models based on convolutional neural networks to obtain head trajectories of the crowd in the survey *** crowd head trajectories are then analyzed to extract crowd quantity and velocities,which are the essential factors for extraordinary *** survey areas with frequent crowd movements during temporary events,the equivalent dynamic load factor can be further estimated using crowd velocity to consider dynamic effects.A crowd quantity investigation experiment and a crowd walking experiment are conducted to validate the proposed survey *** experimental results prove that the proposed survey method is effective and accurate in collecting load data and reasonable in considering dynamic effects during extraordinary *** proposed survey method is easy to deploy and has the potential to collect substantial and reliable extraordinary load data for determining design load on buildings.

关键词： load survey extraordinary load live load object detection multiple-object tracking

A modern survey method for determining live loads based on multi-source and open-access data on the Internet

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Frontiers of Structural and Civil Engineering 2024年第8期18卷 1135-1147页

作者： Chi XU jun chen Jie li School of Civil Engineering Tongji UniversityShanghai 200092China The State Key Laboratory on Disaster Reduction in Civil Engineering Tongji UniversityShanghai 200092China

Sufficient survey data are required to describe the stochastic behaviors of live ***,due to manual and on-site operation required by traditional survey methods,traditional surveys face challenges like occupant resistance,high costs,and long implementation *** study proposes a new survey method to access live load data online and *** samples are acquired from multi-source,open-access and dynamically updated data on the *** change intervals,geometrical dimensions and object quantities are obtained from transaction information,building attributes and virtual reality models on real estate websites,*** object weights are collected from commodity information on e-commerce *** integration of the aforementioned data allows for the extraction of necessary statistics to describe a live load *** proposed method is applied to a live load survey in China,covering 20040 m^(2),with around 90000 samples acquired for object weights and load *** survey results reveal that about 70%−80%of the amplitude statistics are attributable to 1/6 of the total object types.

关键词： live load online survey method data acquisition data integration

Mathematical modeling of flow field in slab continuous casting mold considering mold powder and solidified shell with high temperature quantitative measurement

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Journal of Iron and Steel Research(International) 2022年第3期29卷 445-461页

作者： Yi-bo liu Jian Yang Chao Ma Tao Zhang Fu-bin Gao Tai-quan li jun-li chen State Key Laboratory of Advanced Special Steel School of Materials Science and EngineeringShanghai UniversityShanghai200444China Technology Center HBIS Handan Iron and Steel Group Co.Ltd.Handan56015HebeiChina

Optimization of mathematical model of flow field in slab continuous casting mold was performed by means of industrial measurement and mathematical *** rod deflection method was used to quantitatively measure the velocities near the mold surface at high *** measurement results were compared with the simulation results of three mathematical models at different argon gas flow rates of 6,10 and 14 L min^(−1).The model 1 neglects the mold powder layer,thermal effect and solidified *** model 2 only considers the influence of mold powder *** model 3 considers the influence of mold powder layer,thermal effect and solidified shell on the flow *** all three models,the diameter of argon bubbles obeys Rosin-Rammler distribution fitted according to the experimental data of others’previous *** increasing the argon gas flow rate,the velocity of liquid steel near the mold surface *** model 1 seriously underestimates the shear stress of liquid steel near the mold surface,and its calculation results show higher velocity near the mold surface,lower turbulent kinetic energy and wider distribution of argon gas bubbles in the *** simulation results of model 2 only considering the viscous resistance of the mold powder layer to liquid steel makes the velocity near the surface lower than the measurement results *** calculated velocities near the mold surface with model 3 are in best agreement with the measured results,showing the reasonable spatial distribution range of argon bubbles in the mold and the moderate turbulent kinetic *** the present conditions,the best argon gas flow rate is 10 L min^(−1) due to the moderate velocity near the mold surface,the appropriate distribution of argon gas bubbles in the mold and the smallest fluctuation amplitude on the mold surface.

关键词： Flow field Mold powder layer Solidified shell Rosin-Rammler distribution Mathematical modeling Rod deflection method

Older liver grafts from donation after circulatory death are associated with impaired survival and higher incidence of biliary non-anastomotic structure

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Hepatobiliary & Pancreatic Diseases International 2023年第6期22卷 577-583页

作者： Tian Shen Shan-Hua Zheng jun chen Zhi-Sheng Zhou Meng-Fan Yang Xiang-Yan liu jun-li chen Shu-Sen Zheng Xiao Xu Department of Hepatobiliary and Pancreatic Surgery Shulan(Hangzhou)HospitalHangzhou 310022China Division of Hepatobiliary Pancreatic Surgery The First Affiliated HospitalZhejiang University School of MedicineHangzhou 310003China Key Laboratory of Integrated Oncology and Intelligent Medicine of Zhejiang Province Department of Hepatobiliary and Pancreatic SurgeryAffiliated Hangzhou First People’s HospitalZhejiang University School of MedicineHangzhou 310006China China liver Transplant Registry Hangzhou 310003China NHC Key Laboratory of Combined Multi-organ Transplantation Hangzhou 310003China Institute of Organ Transplantation Zhejiang UniversityHangzhou 310003China

Background:Grafts from older donors after circulatory death were associated with inferior outcome in liver transplants in the *** it has seemed to remain controversial in the last decade,as a result of modified clinical protocols,selected recipients,and advanced technology of organ perfusion and *** present study aimed to examine the impact of older donor age on complications and survival of liver transplant using grafts from donation after circulatory death(DCD).Methods:A total of 944 patients who received DCD liver transplantation from 2015 to 2020 were included and divided into two groups:using graft from older donor(aged≥65 years,n=87)and younger donor(agelied to eliminate selection ***:A progressively increased proportion of liver transplants with grafts from older donors was observed from 1.68%to 15.44%during the study *** well-balanced older donor(n=79)and younger donor(n=79)were 1:1 *** were significantly more episodes of biliary nonanastomotic stricture(NAS)in the older donor group than the younger donor group[15/79(19.0%)vs.6/79(7.6%);P=0.017].The difference did not reach statistical significance regarding early allograft dysfunction(EAD)and primary non-function(PNF).Older livers had a trend toward inferior 1-,2-,3-year graft and overall survival compared with younger livers,but these differences were not statistically significant(63.1%,57.6%,57.6%vs.76.9%,70.2%,67.7%,P=0.112;64.4%,58.6%,58.6%vs.76.9%,72.2%,72.2%,P=0.064).The only risk factor for poor survival was ABO incompatible transplant(P=0.008)in the older donor *** the subgroup of ABO incompatible cases,it demonstrated a significant difference in the rate of NAS between the older donor group and the younger donor group[6/8(75.0%)vs.3/14(21.4%);P=0.014].Conclusions:Transplants with grafts from older donors(aged≥65 years)after circulatory death are more frequently associated with inferior outcome com

关键词： Older donor liver transplantation Survival Biliary stricture Donation after circulatory death

Prognostic implication of early posttransplant hypercholesterolemia in liver transplantation for patients with hepatocellular carcinoma

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Hepatobiliary & Pancreatic Diseases International 2023年第3期22卷 228-238页

作者： Rong-li Wei Guang-Han Fan chen-Zhi Zhang Kang-chen chen Wen-Hui Zhang Chang-Biao li Si-Yi Dong jun-li chen Sun-Bin ling Shu-Sen Zheng Xiao Xu Department of Hepatobiliary and Pancreatic Surgery The Center for Integrated Oncology and Precision MedicineAffiliated Hangzhou First People’s HospitalZhejiang University School of MedicineHangzhou 310006China Department of Hepatobiliary and Pancreatic Surgery The First Affiliated HospitalZhejiang University School of MedicineHangzhou 310003China Institute of Organ Transplantation Zhejiang UniversityHangzhou 310003China National Center for Healthcare Quality Management in liver Transplant Hangzhou 310003China Department of Hepatobiliary and Pancreatic Surgery Shulan(Hangzhou)HospitalHangzhou 310022China

Background: Hyperlipidemia is a common complication after liver transplantation(LT) and develops mostly in the early posttransplant period. Recently, some studies have reported a positive correlation between hyperlipidemia and favorable prognosis in patients with hepatocellular carcinoma(HCC) undergoing hepatectomy. This study aimed to evaluate the possibility of predicting prognosis in HCC patients receiving LT by early posttransplant dyslipidemia. Methods: From January 2015 to December 2017, a total of 806 HCC patients from China liver Transplant Registry database were retrospectively enrolled. The prognostic relevance of early posttransplant hypertriglyceridemia or hypercholesterolemia was examined using survival analysis, and subgroup analysis was implemented based on LT criteria. Results: Early posttransplant hypercholesterolemia(EPHC) was independently inversely associated with the risk of recurrence [hazard ratio(HR) = 0.630;P = 0.022], but was not significantly correlated with the mortality. However, early posttransplant hypertriglyceridemia was not related to prognosis. Intriguingly, with further classification, we found that borderline EPHC(B-EPHC), instead of significant EPHC, was a predictor of lower risk for both recurrence(HR = 0.504;P = 0.006) and mortality(HR = 0.511;P = 0.023). Compared with non-EPHC patients, B-EPHC patients achieved significantly superior 1-year and 3-year tumor-free survival(89.6% and 83.7% vs. 83.8% and 72.7% respectively;P = 0.023), and 1-year and 3-year overall survival(95.8% and 84.8% vs. 94.6% and 77.6% respectively;P = 0.039). In the subgroup analysis, BEPHC remained an independent predictor of better prognosis in patients beyond Milan criteria and those within Hangzhou criteria;whereas there was no significant relationship between B-EPHC and prognosis in patients within Milan criteria and those beyond Hangzhou criteria. More interestingly, patients beyond Milan criteria but within Hangzhou criteria were identified as the c

关键词： liver transplantation Hepatocellular carcinoma Hypercholesterolemia Prognosis

Phosphorylated cellulose nanofibers establishing reliable ion-sieving barriers for durable lithium-sulfur batteries

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Journal of Energy Chemistry 2024年第5期92卷 619-628页

作者： Zihao li Pengsen Qian Hongyang li He Xiao jun chen Gaoran li School of Materials Science and Engineering Nanjing University of Science and TechnologyNanjing 210094JiangsuChina National Forestry and Grassland Administration Key Laboratory of Plant Fiber Functional Materials Fuzhou 350108FujianChina

The shuttle effect is among the most characteristic and formidable challenges in the pursuit of high-performance lithium-sulfur(li-S)***,phosphorylated cellulose nanofibers(pCNF)are intentionally engineered to establish an ion-sieving barrier against polysulfide shuttling and thereby improve battery *** phosphorylation,involving the grafting of phosphate groups onto the cellulose backbone,imparts an exceptional electronegativity that repels the polysulfide anions from penetrating through the ***,the electrolyte wettability and li^(+)transfer can be significantly promoted by the polar nature of pCNF and the facile li^(+)*** such,rational ion management is realized,contributing to enhanced reversibility in both sulfur and lithium *** a result,li-S cells equipped with the self-standing pCNF separator demonstrate outstanding long-term cyclability with a minimum fading rate of 0.013%per cycle over 1000 cycles at 1 C,and a decent areal capacity of 5.37 mA h cm^(-2) even under elevated sulfur loading of 5.0 mg cm^(-2) and limited electrolyte of 6.0 mL g^(-1).This work provides a facile and effective pathway toward the well-tamed shuttle effect and highly durable li-S batteries.

关键词： lithium-sulfur batteries Cellulose Phosphorylation Ion-sieving Shuttle effect