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Dynamic recrystallization mechanism of as-cast nickel base superalloy N10276 during primary hot working

Journal of Iron and Steel Research(International) 2023年第4期30卷 825-837页

作者： xin-chao Wang Yan Wang Xiao-jie lian Mei Xu Li-feng Hou Ying-hui Wei College of Materials Science and Engineering Taiyuan University of TechnologyTaiyuan 030024ShanxiChina State Key Laboratory of Advanced Stainless Steel Materials Taiyuan Iron and Steel(Group)Co.Ltd.Taiyuan 030003ShanxiChina Technology Center Shanxi Taiyuan Stainless Steel Co.Ltd.Taiyuan 030003ShanxiChina

The dynamic recrystallization(DRX)mechanism of as-cast nickel base superalloy N10276 during primary hot working was investigated by compression tests at temperatures of 1000–1200℃ and strain rates between 0.01 and 10 s^(-1).Optical microscopy,scanning electron microscopy,electron backscattered diffraction technique and transmission electron microscopy were used to characterize the evolution of microstructure.At higher deformation temperature or lower strain rate,the true stress–true strain curves exhibit the characteristic of a peak stress followed by a steady state flow stress under large strains,confirming the occurrence of DRX.The degree of DRX increases with elevating deformation temperature.With the progress of DRX,low angle grain boundaries gradually decrease,while high angle grain boundaries increase continuously.Microstructure studies have shown that discontinuous dynamic recrystallization is the main recrystallization mechanism.Since there are few original grain boundaries and twin boundaries,and lack of second phase particles for particle stimulated nucleation,geometrically necessary boundaries are formed as supplementary nucleation sites through sub-grain boundary rotation and deformation twin boundaries.The annealing twins dominated by Σ3 grain boundaries are generated in large quantities during the growth of recrystallized grains.

关键词： Dynamic recrystallization mechanism As-cast superalloy N10276 Primary hot working Twin

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Optimal multi-degree reduction of C-Bezier surfaces with constraints

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Frontiers of Information Technology & Electronic Engineering 2017年第12期18卷 2009-2016页

作者： lian ZHOU xin-hui LIN Hong-yan ZHAO Jun CHEN Department of Mathematics Shanghai Maritime University Zhejiang Institute of Economics and Trade College of Fundamental Studies Shanghai University of Engineering Science Faculty of Science Ningbo University of Technology

本文提出了一种在L_2范数下C-Bézier曲面带约束条件的降多阶逼近最优方法。利用C-Bézier基函数的转换矩阵,得到了降阶曲面控制顶点的显式矩阵表示。结合指定的边界约束条件,该法利用于对分片连续曲面或细分子曲面同时降多阶逼近,所得... 详细信息

本文提出了一种在L_2范数下C-Bézier曲面带约束条件的降多阶逼近最优方法。利用C-Bézier基函数的转换矩阵,得到了降阶曲面控制顶点的显式矩阵表示。结合指定的边界约束条件,该法利用于对分片连续曲面或细分子曲面同时降多阶逼近,所得到的系列降阶曲面整体上保持G^1连续。数值实验表明该方法的优质高效。

关键词： C-Bézier曲面降阶边界约束

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Medical services for sports injuries and illnesses in the Beijing 2022 Olympic Winter Games

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World Journal of Emergency Medicine 2022年第6期13卷 459-466页

作者： Peng-da Han Ding Gao Jie Liu Jing Lou Si-jia Tian Hui-xin Lian Sheng-mei Niu Lu-xi Zhang Yong Wang Jin-jun Zhang Emergence Medical Service Group for Beijing 2022 Olympic Winter Games Beijing Emergency Medical CenterBeijing 100031China Department of General Surgery Beijing Tongren HospitalCapital Medical UniversityBeijing 100730China Games Services Department Beijing Organizing Committee for the 2022 Olympic and Paralympic Winter GamesBeijing100041China

BACKGROUND:Beijing 2022 Olympic Winter Games was the second Games held amid the COVID-19 pandemic.To a certain extent,it has altered the way sporting activities operate.There is a lack of knowledge on injury risk and illness occurrence in elite winter sport athletes amid the COVID-19 pandemic.This study aimed to describe the incidence of injuries and illnesses sustained during the XXIV Olympic Winter Games in Beijing from February 4 to 20,2022.METHODS:We recorded the daily number of injuries and illnesses among athletes reported by Beijing 2022 medical staff in the polyclinic,medical venues,and ambulance.We calculated injury and illness incidence as the number of injuries or illnesses occurring during competition or training,respectively,with incidence presented as injuries/illnesses per 100 athlete-days.RESULTS:In total,2,897 athletes from 91 nations experienced injury or illness.Beijing 2022 medical staff reported 326 injuries and 80 illnesses,equaling 11.3 injuries and 2.8 illnesses per 100 athletes over the 17-day period.Altogether,11%of the athletes incurred at least one injury and nearly 3%incurred at least one illness.The number of injured athletes was highest in the skating sports(n=104),followed by alpine skiing(n=53),ice track(n=37),freestyle skiing(n=36),and ice hockey(n=35),and was the lowest in the Nordic skiing disciplines(n=20).Of the 326 injuries,14(4.3%)led to an estimated absence from training or competition of more than 1 week.A total of 52 injured athletes were transferred to hospitals for further care.The number of athletes with illness(n=80)was the highest for skating(n=33)and Nordic skiing(n=22).A total of 50 illnesses(62.5%)were admitted to the department of dentistry/ophthalmology/otolaryngology,and the most common cause of illness was other causes,including preexisting illness and medicine(n=52,65%).CONCLUSION:Overall,11%of athletes incurred at least one injury during the Games,which is similar to the findings during the Olympic Winter Games in 2014 and 2018.Regarding illness,2%of athlet

关键词： Injuries Illnesses Olympic Winter Games Emergency medical service

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Existence of multiple solutions for the laminar flow in a porous channel with suction at both slowly expanding and contracting walls

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International Journal of Minerals,Metallurgy and Materials 2011年第4期18卷 494-501页

作者： xin-hui Si lian-cunZheng xin-xin Zhang Ying Chao Applied Science School University of Science and Technology Beijing Beijing 100083 China Department of Mechanical Engineering University of Science and Technology Beijing Beijing 100083 China Chemical Defense Institute of the PLA Beijing 102205 China

The asymptotic behavior of solutions of a similarity equation for the laminar flow in a porous channel with suction at both expanding and contracting walls has been obtained by using a singular perturbation method. However, in the matching process, this solution neglects exponentially small terms. To take into account these exponentially small terms, a method involving the inclusion of exponentially small terms in a perturbation series was used to find two of the solutions analytically. The series involving the exponentially small terms and expansion ratio predicts dual solutions. Furthermore, the result indicates that the expansion ratio has much important influence on the solutions.

关键词： laminar flow porous channels multiple solutions singular perturbation method

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Experimental Study on Vortex-Induced Vibration of Marine Riser Model with Coupling Interference Effect Under Combined Internal and External Flow

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中国海洋工程:英文版 2023年第4期37卷 673-684页

作者： REN Xiao-hui LI Peng CHEN xin WANG Ye-shuo LIU Zhen HAO lian-hong WANG Yu HUANG Yi-jie College of Architecture and Civil Engineering Shandong University of Science and TechnologyQingdao 266590China Qingdao Key Laboratory of Marine Civil Engineering Materials and Structures Qingdao 266590China School of Petroleum Engineering China University of Petroleum(East China)Qingdao 266580China

A partition model of interference efficiency was constructed to study the coupling interference effect under combined internal and external flow.The concept of“internal flow efficiency”,“velocity ratio”and“interference efficiency”were introduced to quantify the effect of internal flow and interference,and reveal the coupling mechanism among internal flow,external flow and interference effect.The results showed that the dynamic response of risers under variable angles was significantly different after considering the effect of internal flow.When the external flow velocity was smaller than 0.25 m/s,the vibration of risers was promoted by the internal flow.With the increase of external flow velocity,the effect of internal flow was weakened and the dynamic response of riser mainly depended on the external flow and interference effect.Under the effect of different internal flow,the interference efficiency had similar change trend.The interference effect amplified the complex secondary flow effect inside the riser,making the dynamic response of riser complex and random.In this paper,the overlap area and subdivision criterion of interference effect were constructed within the range of experimental velocity ratio,and the change curve of interference efficiency was obtained with an average meaning,which may have important practical meaning.

关键词： marine riser vortex-induced vibration internal flow interference effect interference efficiency internal flow efficiency

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“Charging”the cigarette butt:heteroatomic porous carbon nanosheets with edge-induced topological defects for enhanced oxygen evolution performance

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Frontiers of Chemical Science and Engineering 2023年第11期17卷 1755-1764页

作者： Qing-hui Kong Xian-Wei Lv Jin-Tao Ren Hao-Yu Wang xin-lian Song Feng Xu Zhong-Yong Yuan School of Materials Science and Engineering Smart Sensing Interdisciplinary Science CenterNankai UniversityTianjin 300350China Tianjin Workstation Technology Center of Shanghai Tobacco Group Co.Ltd.Tianjin 300163China Key Laboratory of Advanced Energy Materials Chemistry(Ministry of Education) Nankai UniversityTianjin 300071China

Owing to the complexity of electron transfer pathways,the sluggish oxygen evolution reaction process is defined as the bottleneck for the practical application of Zn-air batteries.In this effort,metal nanoparticles(Co,Ni,Fe,etc.)encapsulated within nitrogen-doped carbon materials with abundant edge sites were synthesized by one-step pyrolysis treatment using cigarette butts as raw materials,which can drastically accelerate the overall rate of oxygen evolution reaction by facilitating the adsorption of oxygenated intermediates by the edge-induced topological defects.The prepared catalyst of nitrogen-doped carbon porous nanosheets loaded with Co nanoparticles(Co@NC-500)exhibits enhanced catalytic activity toward oxygen evolution reaction,with a low overpotential of 350 mV at the current density of 10 mA·cm^(-2).Furthermore,the Zn-air battery assembled with Co@NC-500 catalyst demonstrates a desirable performance affording an open-circuit potential of 1.336 V and power density of 33.6 mW·cm^(-2),indicating considerable practical application potential.

关键词： oxygen evolution reaction porous carbon nanosheets Co nanoparticles edge-induced topological defects Zn-air batteries

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Contrast-enhanced ultrasound as a valuable imaging modality for characterizing testicular lesions

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Asian Journal of Andrology 2022年第2期24卷 201-206页

作者： Jie Yu xin-hui Jiang lian-Fang Du Min Bai Zhao-Jun Li Qiu-Sheng Shi Qi Jiang Fan Li Department of Ultrasound Shanghai General HospitalShanghai Jiao Tong University School of MedicineShanghai 201620China Department of Medical Ultrasound Shanghai Baoshan Hospital of Integrated Traditional Chinese and Western MedicineShanghai 201999China Department of Urology Shanghai General HospitalShanghai Jiao Tong University School of MedicineShanghai 200080China

Contrast-enhanced ultrasound(CEUS)is a new form of ultrasound(US)that can dynamically display microvessels in a highly sensitive manner.The purpose of this study was to investigate the efficacy of CEUS for characterizing testicular lesions in comparison with conventional US.Forty-seven patients with testicular lesions were enrolled.The histopathology results revealed that 31 cases were neoplastic(11 cases of seminomas,8 nonseminomatous germ cell tumors,8 lymphomas,2 Leydig cell tumors,and 2 nonspecific tumors),and 16 cases were nonneoplastic(8 cases of infarctions,3 epidermoid cysts,and 5 inflammation).The indicators of shallow lobulated morphology and cystic-solid echogenicity on conventional US were suggestive of germ cell tumors.More indicators on CEUS were found to be useful for characterizing testicular lesions.All the neoplastic lesions showed hyperenhancement on CEUS.Moreover,germ cell tumors presented with heterogeneous enhancement(73.7%,14/19),a twisted blood vessel pattern,rapid wash-in and wash-out,and peripheral rim hyperenhancement signs.Lymphoma was characterized by nonbranching linear vessel patterns(87.5%,7/8),rapid wash-in and slow wash-out.In nonneoplastic lesions,infarction and epidermoid cysts showed no enhancement,and abscesses were observed with marginal irregular enhancement.The sensitivity,specificity,and accuracy of CEUS for differentiating between neoplastic and nonneoplastic lesions were 100%,93.8%,and 97.9%,respectively,and these values were higher than those for conventional US(90.3%,62.5%,and 80.9%,respectively).CEUS can sensitively reflect the microvascular perfusion in testicular lesions and offers high accuracy for characterizing them.

关键词： characterization contrast-enhanced ultrasound diagnosis testicular neoplasms ultrasound

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Combined therapy versus anti-vascular endothelial growth factor monotherapy for polypoidal choroidal vasculopathy： a Meta-analysis

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International Journal of Ophthalmology(English edition) 2017年第8期10卷 1280-1289页

作者： Long-hui Han Li-Fei Yuan Xu liang xin Jia Ming-lian Zhang Hebei Provincial Eye Institute Hebei Provincial Eye HospitalXingtai 054001 Hebei Province China Tianjin Eye Hospital Tianjin 300020 China

AIM： To evaluate the efficacy and safety of anti-vascular endothelial growth factor （VEGF） combined with photodynamic therapy （PDT） versus anti-VEGF monotherapy for polypoidal choroidal vasculopathy （PCV）. METHODS： We conducted a Meta-analysis of 9 studies to compare the efficacy and safety between combined therapy and anti-VEGF monotherapy for PCV. The programs of RevMan 5.3 and Stata 12.0 were used to analyze data. RESULTS： The best corrected visual acuity （BCVA） in combined therapy group were significantly better than those of anti-VEGF monotherapy group at 6, 24 and 36mo, with pooled weighted means differences （WMDs） of 0.12 （0.06, 0.18）, 0.25 （0.12, 0.38） and 0.28 （0.13, 0.43）, respectively. The central retinal thickness （CRT） reductions in combined therapy group were higher than that in anti- VEGF monotherapy group at 1, 3, 6 and 9mo, with pooled WMDs of 63.90 （20.41, 107.38）, 33.47 （4.69, 62.24）, 30.57 （0.12, 60.01） and 28.00 （2.51, 53.49）, respectively. The regression rate of polyps in combined therapy group was much higher than that in anti-VEGF monotherapy group [RD： 0.47 （0.26, 0.68）; P〈0.0001]. The adverse event retinal hemorrhage did not differ significantly between the two groups. CONCLUSION： Our findings clearly document that anti- VEGF combined with PDT is a more effective therapy for PCV compared with anti-VEGF monotherapy. Furthermore, combined therapy does not increase the incidence of retinal hemorrhage.

关键词： vascular endothelial growth factor photodynamic therapy polypoidal choroidal vasculopathy

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Treponema pallidum-specific antibody expression for the diagnosis of different stages of syphilis

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Chinese Medical Journal 2013年第2期126卷 206-210页

作者： SUN Ran LAI Di-hui REN Rong-xin lian Shi ZHANG Hai-ping Department of Dermatology and Venereology Xuanwu HospitalCapital Medical Universitw Beiiing 100053 China Department of Dermatology and Venereology Chinese Academyof Medical Sciences and Peking Union Medical College Beijing100730 China Department of Dermatology and Venereology Capital MedicalUniversity Beijing 100069 China

Background Tp15, Tp17, Tp45, and Tp47 are outer-membrane proteins found in Treponema pallidum, the etiologic agent of syphilis. These proteins are potent antigens and are potential markers for the serological detection of syphilis. The present study analyzed antibodies to these protein antigens （TP-IgM and TP-IgG） in human serum and investigated the expression of these antibodies during different stages of syphilis. Methods Serum samples were collected from 69 subjects （male 45, female 24） diagnosed with syphilis and analyzed by Western blotting for the expression of IgM and IgG against the four protein antigens. Expression levels of the target antibodies were compared during the same stage of syphilis as well as between different stages of this disease. Results In subjects with primary syphilis, the positive rate of Tp45 IgM was higher than that of other TP-IgM. Tp15 IgM was detected only in subjects with tertiary syphilis. Similarly, the seroprevalence of Tp45 IgG in primary syphilis was higher than for other TP-IgG. No target TP-IgM was detected in subjects with latent syphilis. In subjects with secondary syphilis, the expression level of Tp15 IgG （138.73±20.16） was higher than for other target TP-IgG. In subjects with tertiary syphilis, all target TP-IgG were detected. In subjects with tertiary or latent syphilis, the expression levels of Tp45 IgG （121.33±11.04 and 110.10±40.19, respectively） were higher than those of other target TP-IgG. The expression levels of all Tp-lgM were similar before or after anti-syphilis treatment. In comparison, the expression levels of all TP-IgG decreased compared with the pre-treatment levels, and this decrease was statistically significant （both P 〈0.05） for Tp17 IgG and Tp47 IgG. Conclusions After Treponema pallidum infection, Tp45 IgM appeared first and Tp15 IgM occurred during later stages. The positive rates of all TP-IgG increased with the duration of this disease. Anti-syphilis treatment reduced the expression levels of Tp17 IgG and Tp47 IgG. Larger-scale studies are re

关键词： Treponema pallidum Western blotting, syphilis

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Three new pyrrole alkaloids from the endophytic fungus Albifimbria viridis

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Natural Products and Bioprospecting 2022年第1期12卷 51-55页

作者： Pan-Pan Wei Jia-Cheng Ji Xu-Jun Ma Zheng-hui Li Hong-lian Ai xin-Xiang Lei Ji-Kai Liu School of Pharmaceutical Sciences South-Central University for NationalitiesWuhan 430074People’s Republic of China

Three new pyrrole alkaloids albifipyrrols A-C(1-3),were isolated from the endophytic fungus Albifimbria viridis col-lected from the Chinese medicinal plant.Their structures were elucidated by extensive NMR and HRESIMS spectro-metric analyses.All compounds were evaluated for immunosuppressive activity.Fortunately,compound 2 exhibits certain inhibition specifically against the LPS-induced proliferation of B lymphocyte cells with IC50 value 16.16μM.

关键词： Pyrrole alkaloids Coptis chinensis Endophytic fungus Albifimbria viridis Immunosuppressive activity

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