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npj Computational Materials 2019年第1期5卷 442-453页

作者： Yangyiwei Yang Olav Ragnvaldsen Yang bai Min Yi bai-Xiang xu Mechanics of Functional Materials Division Institute of Materials ScienceTechnische Universität Darmstadt64287 DarmstadtGermany Department of Materials Science and Engineering Norwegian University of Science and Technology7491 TrondheimNorway State Key Laboratory of Mechanics and Control of Mechanical Structures&Key Laboratory for Intelligent Nano Materials and Devices of Ministry of Education&College of Aerospace Engineering Nanjing University of Aeronautics and Astronautics(NUAA)210016 NanjingChina

During selective laser sintering(SLS),the microstructure evolution and local temperature variation interact mutually.Application of conventional isothermal sintering model is thereby insufficient to describe SLS.In this work,we construct our model from entropy level,and derive the non-isothermal kinetics for order parameters along with the heat transfer equation coupled with microstructure evolution.Influences from partial melting and laser-powder interaction are also addressed.We then perform 3D finite element non-isothermal phase-field simulations of the SLS single scan.To confront the high computation cost,we propose a novel algorithm analogy to minimum coloring problem and manage to simulate a system of 200 grains with grain tracking algorithm using as low as 8 non-conserved order parameters.Specifically,applying the model to SLS of the stainless steel 316L powder,we identify the influences of laser power and scan speed on microstructural features,including the porosity,surface morphology,temperature profile,grain geometry,and densification.We further validate the first-order kinetics of the transient porosity during densification,and demonstrate the applicability of the developed model in predicting the linkage of densification factor to the specific energy input during SLS.

关键词： microstructure isothermal kinetics

Diabetes mellitus in patients with type 1 autoimmune pancreatitis at diagnosis and after corticosteroid therapy

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Hepatobiliary & Pancreatic Diseases International 2024年第4期23卷 393-398页

作者： Mei-Zi Li Tao Guo Yun-Lu Feng Sheng-Yu Zhang Xiao-Yin bai Xi Wu Kai xu Ai-Ming Yang Department of Gastroenterology State Key Laboratory of Complex Severe and Rare DiseasesPeking Union Medical College HospitalPeking Union Medical College and Chinese Academy of Medical SciencesBeijing 100730China Department of Radiology Peking Union Medical College HospitalPeking Union Medical College and Chinese Academy of Medical SciencesBeijing 100730China

Background:A high prevalence of diabetes mellitus(DM)coexisting with autoimmune pancreatitis(AIP)is observed.However,evidence on the circumstances under which corticosteroid therapy(CST)for AIP improves or worsens DM is scarce.This study aimed to demonstrate and identify predictors of DM control under the influence of CST.Methods:Patients diagnosed with type 1 AIP were enrolled from a prospectively maintained cohort and were classified into three groups according to the chronology in which AIP and DM were diagnosed:pre-existing DM(pDM),concurrent DM(cDM),and non-DM(nDM).The responses of DM to CST were assessed when corticosteroid was ceased or tapered to a maintenance dose and classified as‘improvement’and‘non-improvement’(including‘no change’and‘exacerbation’).Results:Among 101 patients with type 1 AIP,52(51.5%)patients were complicated with DM at the time of AIP diagnosis,with 36 patients in the cDM group and 16 patients in the pDM group.The incidences of diffuse pancreatic swelling(72.2%)and pancreatic body/tail involvement(91.7%)were significantly higher in the cDM group than in both the pDM and nDM groups.Of the 52 patients with DM,CST was administered in 48 cases.Multivariate logistic analysis identified that elevated serum gamma-glutamyl transferase(GGT)level at AIP diagnosis[odds ratio(OR)=0.032,95%confidence interval(CI):0.003-0.412,P=0.008]and pancreatic atrophy after CST(OR=0.027,95%CI:0.003-0.295,P=0.003)were negatively associated with DM control improvement.Conclusions:Patients with diffuse pancreatic swelling and pancreatic body/tail involvement in pancreatitis tended to be complicated with cDM at AIP diagnosis.CST exerted a beneficial effect on the clinical course of DM in nearly half of the AIP patients complicated with DM at diagnosis,particularly in those without elevated serum GGT levels at diagnosis and who did not experience pancreatic atrophy after CST.

关键词： Type 1 autoimmune pancreatitis Diabetes mellitus Corticosteroid therapy Predictive factor Pancreatic atrophy

Clinical efficacy and pathological outcomes of transanal endoscopic intersphincteric resection for low rectal cancer

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World Journal of Gastrointestinal Oncology 2024年第3期16卷 933-944页

作者： Zhi-Wen xu Jing-Tao Zhu Hao-Yu bai xue-Jun Yu Qing-Qi Hong Jun You Department of Gastrointestinal Oncology Surgery The First Affiliated Hospital of Xiamen UniversitySchool of MedicineXiamen UniversityXiamen 361000Fujian ProvinceChina

BACKGROUND Transanal endoscopic intersphincteric resection(ISR)surgery currently lacks sufficient clinical research and reporting.AIM To investigate the clinical effectiveness of transanal endoscopic ISR,in order to promote the clinical application and development of this technique.METHODS This study utilized a retrospective case series design.Clinical and pathological data of patients with lower rectal cancer who underwent transanal endoscopic ISR at the First Affiliated Hospital of Xiamen University between May 2018 and May 2023 were included.All patients underwent transanal endoscopic ISR as the surgical approach.We conducted this study to determine the perioperative recovery status,postoperative complications,and pathological specimen charac-teristics of this group of patients.RESULTS This study included 45 eligible patients,with no perioperative mortalities.The overall incidence of early complications was 22.22%,with a rate of 4.44%for Clavien-Dindo grade≥III events.Two patients(4.4%)developed anastomotic leakage after surgery,including one case of grade A and one case of grade B.Postoperative pathological examination confirmed negative circumferential resection margins and distal resection margins in all patients.The mean distance between the tumor lower margin and distal resection margin was found to be 2.30±0.62 cm.The transanal endoscopic ISR procedure consistently yielded high quality pathological specimens.CONCLUSION Transanal endoscopic ISR is safe,feasible,and provides a clear anatomical view.It is associated with a low incidence of postoperative complications and favorable pathological outcomes,making it worth further research and application.

关键词： Intersphincteric resection Transanal Rectal cancer Complications Endoscopic

Voltage-driven charge-mediated fast 180 degree magnetization switching in nanoheterostructure at room temperature

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npj Computational Materials 2017年第1期3卷 137-145页

作者： Min Yi Hongbin Zhang bai-Xiang xu Department of Materials and Earth Sciences Technische Universitat Darmstadt64287 DarmstadtGermany

Voltage-driven 180°magnetization switching without electric current provides the possibility for revolutionizing the spintronics.We demonstrated the voltage-driven charge-mediated 180°magnetization switching at room temperature by combining firstprinciples calculations and temperature-dependent magnetization dynamics simulation.The electric field(E)-induced interface charge is found to allow a giant modulation of the magnetic anisotropy(K)of the nanomagnet.Particularly K is revealed to vary linearly with respect to E and the epitaxial strain.Magnetization dynamics simulations using the so-obtained K show that both inplane and perpendicular 180°switching can be achieved by E pulses.The temperature effect renders the 180°switching as probability events.Statistical analysis indicates a fast(around 4 ns)and low-error-probability 180°switching achievable at room temperature by controlling the magnitude of E and the pulse width.The study inspires the rational design of miniaturized nanoscale spintronic devices where thermal fluctuation has a great impact.

关键词： magnetization charge render

Respiratory manifestations in amyloidosis

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Chinese Medical Journal 2005年第24期118卷 2027-2033页

作者： xu Ling CAI bai-qiang ZHONG xu ZHU Yuan-jue Department of Respiratory Medicine Peking Union Medical CollegeHospital Peking Union Medical College Chinese Academy ofMedical Sciences Beijing 100730 China

Background Amyloidosis is a collection of diseases in which different proteins are deposited. Amyloid deposits occur in systemic and organ-limited forms. In both systemic and localized forms of the disease, lung can he involved. The aim of this study was to explore the different respiratory manifestations of amyloidosis. Methods Chest radiology, clinical presentations, bronchoscopic/laryngoscopic findings and lung function data of 59 patients with amyloidosis involving respiratory tract collected during January 1986 to March 2005, were analysed. Results Of the 16 cases with localized respiratory tract amyloidosis, 8 had the lesions in the trachea and the bronchi, 2 in the larynx and the trachea, 5 in the larynx and/or the pharynx, and 1 in the lung parenchyma. Of 43 systemic amyloidosis with respiratory tract involvement, 3 had the lesions in bronchi, 13 in lung parenehyma, 33 in pleura, 8 in mediastina, 1 in nose and 1 in pharynx. Chest X-rays were normal in most cases of tracheobronchial amyloidosis. CT, unlike chest X-rays, showed irregular luminal narrowing, airway wall thickening with calcifications and soft tissue shadows in airway lumen. Localized lung parenchymal amyloidosis presented as multiple nodules. Multiple nodular opacities, patch shadows and reticular opacities were the main radiological findings in systemic amyloidosis with lung parenchymal involvement. In pleural amyloidosis, pleural effusions and pleural thickening were detected. Mediastinal and/or hilar adenopathy were also a form of lung involvement in systemic amyloidosis. The major bronehoseopie findings of tracheobronchial amyloidosis were narrowing of airway lumen, while nodular, ＇ tumour like＇ or ＇ bubble like＇ masses, with missing or vague cartilaginous rings, were detected in about half of the patients. Conclusions Localized respiratory tract amyloidosis mostly affects the trachea and the bronchi. Chest X-rays are not sensitive to detect these lesions. Systemic amyloidosis often involves lung parenchyma and the pleura. Open lung b

关键词： amyloiclosis trachea bronchus lung pleural effusion

Instrumented oscillographic study on impact toughness of an axle steel DZ2 with different tempering temperatures

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International Journal of Minerals,Metallurgy and Materials 2024年第7期31卷 1590-1598页

作者： Shuo Liu Peng Zhang Bin Wang Kaizhong Wang Zikuan xu Fangzhong Hu Xin bai Qiqiang Duan Zhefeng Zhang Shi-changxu Innovation Center for Advanced Materials Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China School of Materials Science and Engineering University of Science and Technology of ChinaShenyang 110016China Technology Center Ma'anshan Iron and Steel Co.Ltd.Ma'anshan 243000China

Compared with the conventional Charpy impact test method,the oscillographic impact test can help in the behavioral analysis of materials during the fracture process.In this study,the trade-off relationship between the strength and toughness of a DZ2 axle steel at various tempering temperatures and the cause of the improvement in impact toughness was evaluated.The tempering process dramatically influenced carbide precipitation behavior,which resulted in different aspect ratios of carbides.Impact toughness improved along with the rise in tempering temperature mainly due to the increase in energy required in impact crack propagation.The characteristics of the impact crack propagation process were studied through a comprehensive analysis of stress distribution,oscilloscopic impact statistics,fracture morphology,and carbide morphology.The poor impact toughness of low-tempering-temperature specimens was attributed to the increased number of stress concentration points caused by carbide morphology in the small plastic zone during the propagation process,which resulted in a mixed distribution of brittle and ductile fractures on the fracture surface.

关键词： axle steel DZ2 tempering process impact toughness oscillographic impact test impact crack propagation carbides

An efficient adaptive finite element method algorithm with mass conservation for analysis of liquid face seals

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2014年第3期15卷 172-184页

作者： Xiayg-kai MENG Shao-xian bai xu-dong PENG Institute of Chemical Process Machinery Zhejiang University of Technology Hangzhou 310032 China

研究目的:为液体润滑端面密封空化问题的数值模拟提供一种高效精确的计算方法。创新要点:1.采用流线迎风SUPG有限元法求解具有对流扩散特征的控制方程;2.针对未知量的互补关系提出了一种高效的数值迭代技术;3.提供了针对润滑液膜空化问... 详细信息

研究目的:为液体润滑端面密封空化问题的数值模拟提供一种高效精确的计算方法。创新要点:1.采用流线迎风SUPG有限元法求解具有对流扩散特征的控制方程;2.针对未知量的互补关系提出了一种高效的数值迭代技术;3.提供了针对润滑液膜空化问题的网格自适应技术。重要结论:1.相比文献算法,本文算法具有计算速度快,计算精度高的优点;2.空化区域和大压力梯度区域的计算网格得到加密。

关键词：空化有限元法端面密封流线迎风伽辽金法SUPG法质量守恒

Single-cluster electronics using metallic clusters:Fabrications,regulations,and applications

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Nano Research 2024年第1期17卷 65-78页

作者： Caiyun Wei Wei xu Shurui Ji Ruiyun Huang Junyang Liu Wenqiu Su Jie bai Jiale Huang Wenjing Hong State Key Laboratory of Physical Chemistry of Solid Surfaces National Engineering Research Centre of Chemicals for Electronic ManufacturingCollege of Chemistry and Chemical Engineering&Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province(IKKEM)Xiamen UniversityXiamen 361005China

Metallic clusters,ranging from 1 to 2 nm in size,have emerged as promising candidates for creating nanoelectronic devices at the single-cluster level.With the intermediate quantum properties between metals and semiconductors,these metallic clusters offer an alternative pathway to silicon-based electronics and organic molecules for miniaturized electronics with dimensions below 5 nm.Significant progress has been made in studies of single-cluster electronic devices.However,a clear guide for selecting,synthesizing,and fabricating functional single-cluster electronic devices is still required.This review article provides a comprehensive overview of single-cluster electronic devices,including the mechanisms of electron transport,the fabrication of devices,and the regulations of electron transport properties.Furthermore,we discuss the challenges and future directions for single-cluster electronic devices and their potential applications.

关键词： single-cluster junctions electronic properties electron transport metallic clusters structure regulation

Effect of chemical regulators on the recovery of leaf physiology,dry matter accumulation and translocation,and yield-related characteristics in winter wheat following dry-hot wind

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Journal of Integrative Agriculture 2024年第1期23卷 108-121页

作者： Yanan xu Yue Wu Yan Han Jiqing Song Wenying Zhang Wei Han Binhui Liu Wenbo bai Institute of Environment and Sustainable Development in Agriculture Chinese Academy of Agricultural SciencesBeijing 100081China Institute of Dryland Farming Research Hebei Academy of Agriculture and Forestry SciencesHengshui 053000China Shandong General Station of Agricultural Technology Extension Jinan 250100China

Dry-hot wind stress causes losses in wheat productivity in major growing regions worldwide,especially winter wheat in the Huang-Huai-Hai Plain of China,and both the occurrence and severity of such events are likely to increase with global climate change.To investigate the recovery of physiological functions and yield formation using a new noncommercial chemical regulator(NCR)following dry-hot wind stress,we conducted a three-year field experiment(2018-2021)with sprayed treatments of tap water(control),monopotassium phosphate(CKP),NCR at both the jointing and flowering stages(CFS),and NCR only at the jointing stage(FSJ)or flowering stage(FSF).The leaf physiology,biomass accumulation and translocation,grain-filling process,and yield components in winter wheat were assessed.Among the single spraying treatments,the FSJ treatment was beneficial for the accumulation of dry matter before anthesis,as well as larger increases in the maximum grain-filling rate and mean grain-filling rate.The FSF treatment performed better in maintaining a high relative chlorophyll content as indicated by the SPAD value,and a low rate of excised leaf water loss in flag leaves,promoting dry matter accumulation and the contribution to grain after anthesis,prolonging the duration of grain filling,and causing the period until the maximum grain-filling rate reached earlier.The CFS treatment was better than any other treatments in relieving the effects of dry-hot wind.The exogenous NCR treatments significantly increased grain yields by 12.45-18.20% in 2018-2019,8.89-13.82% in 2019-2020,and 8.10-9.00% in 2020-2021.The conventional measure of the CKP treatment only increased grain yield by 6.69% in 2020-2021.The CFS treatment had the greatest mitigating effect on yield loss under dry-hot wind stress,followed by the FSF and FSJ treatments,and the CKP treatment only had a minimal effect.In summary,the CFS treatment could be used as the main chemical control measure for wheat stress resistance and yield stability in areas with a high incidence of dry-

关键词： preparation stress foliar spraying grain-filling remobilization