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Positive Solutions for Asymptotically Linear Cone-Degenerate Elliptic Equations

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Chinese Annals of Mathematics,Series B 2022年第5期43卷 685-718页

作者： hua CHEN Peng LUO Shuying tian School of Mathematics and Statistics Wuhan UniversityWuhan 430072China School of Mathematics and Statistics Central China Normal UniversityWuhan 430079China Department of Mathematics School of ScienceWuhan University of TechnologyWuhan 430070China

In this paper,the authors study the asymptotically linear elliptic equation on manifold with conical singularities-ΔBu+λu=a(z)f(u),u≥0 in R+N,where N=n+1≥3,λ>0,z=(t,x_(1),…,x_(n)),and ΔB=(t■t)^(2)+■^(2)x_(1)+…+■^(2)x_(n).Combining properties of cone-degenerate operator,the Pohozaev manifold and qualitative properties of the ground state solution for the limit equation,we obtain a positive solution under some suitable conditions on a and f.

关键词： Asymptotically linear Pohozaev identity Cone degenerate elliptic operators

Traditional investigation and management for recurrent hemarthrosis after total knee arthroplasty: A case report

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World Journal of Clinical Cases 2020年第10期8卷 1966-1972页

作者： Xiao Geng Yang Li Xuan He Hua Tian Orthopedic Department Peking University Third HospitalBeijing 100191China

BACKGROUND Recurrent hemarthrosis is a rare complication of total knee arthroplasty,and only a few cases have been reported;hence,it is hard to establish comprehensive diagnosis and treatment guidelines.We here report a case of recurrent hemarthrosis after total knee arthroplasty,and briefly review the literature.CASE SUMMARY A 50-year-old man,with a history of hypertension,presented to the Orthopedic Department of our hospital for non-traumatic acute left knee pain and swelling associated with a warmth sensation 14 mo after total knee arthroplasty.Investigations(ultrasound,aspiration,and arthroscopy)and managements(nonsurgical,arthroscopy and open exploration)were performed,and the clinical effects of these interventions were analyzed separately.Clinical evidence indicates that the cause of this case was rupture of a pseudoaneurysm of the medial superior genicular artery.CONCLUSION The present case indicated that angiography is essential in cases of hemarthrosis after TKA;arthroscopy may not always be adequate as it may not provide a clear view;and traditional open exploration is still effective and sometimes necessary.

关键词： Total knee arthroplasty Recurrent hemarthrosis Arthroscopy Open exploration Case report

Role of reactive oxygen species in epithelial-mesenchymal transition and apoptosis of human lens epithelial cells

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International Journal of Ophthalmology(English edition) 2023年第12期16卷 1935-1941页

作者： Rui-hua Jing Cong-Hui Hu tian-tian Qi Bo Ma Department of Ophthalmology the Second Affiliated Hospital of Xi’an Jiaotong UniversityXi’an 710004Shaanxi ProvinceChina Department of Ophthalmology the First Affiliated Hospital of Xi’an Jiaotong UniversityXi’an 710061Shaanxi ProvinceChina

AIM:To investigate the role of reactive oxygen species(ROS)in epithelial–mesenchymal transition(EMT)and apoptosis of human lens epithelial cells(HLECs).METHODS:Flow cytometry was used to assess ROS production after transforming growth factorβ2(TGF-β2)induction.Apoptosis of HLECs after H_(2)O_(2) and TGF-β2 interference with or without ROS scavenger N-acetylcysteine(NAC)were assessed by flow cytometry.The corresponding protein expression levels of the EMT markerα-smooth muscle actin(α-SMA),the extracellular matrix(ECM),marker fibronectin(Fn),and apoptosis-associated proteins were detected by using Western blotting in the presence of an ROS scavenger(NAC).Wound-healing and Transwell assays were used to assess the migration capability of HLECs.RESULTS:TGF-β2 stimulates ROS production within 8h in HLECs.Additionally,TGF-β2 induced HLECs cell apoptosis,EMT/ECM synthesis protein markers expression,and pro-apoptotic proteins production;nonetheless,NAC treatment prevented these responses.Similarly,TGF-β2 promoted HLECs cell migration,whereas NAC inhibited cell migration.We further determined that although ROS initiated apoptosis,it only induced the accumulation of the EMT markerα-SMA protein,but not COL-1 or Fn.CONCLUSION:ROS contribute to TGF-β2-induced EMT/ECM synthesis and cell apoptosis of HLECs;however,ROS alone are not sufficient for EMT/ECM synthesis.

关键词： human lens epithelial cells epithelial-mesenchymal transition transforming growth factorβ2 reactive oxygen species apoptosis

Modelling and analysis of metal flowing behaviors in constraining ring rolling of tapered ring with thin wall and three high ribs

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Chinese Journal of Aeronautics 2023年第6期36卷 476-492页

作者： Lin hua Duanyang tian Xinghui HAN Wuhao ZhuaNG Hubei Key Laboratory of Advanced Technology for Automotive Components Wuhan University of TechnologyWuhan 430070China Hubei Longzhong Laboratory Xiangyang 441000China School of Automotive Engineering Wuhan University of TechnologyWuhan 430070China

Tapered ring with thin wall and three high ribs(TRTWTHR),showing complicated geometry(wall thickness is less than 4 mm and rib height exceeds 20 mm),is extensively utilized to fabricate the critical structural parts of aerospace equipment such as spacecraft cabin,rocket body and fuel tank because of light weight and high carrying capacity.How to fabricate TRTWTHR with high performance is a critical problem that aerospace area needs to solve.In this work,constraining ring rolling(CRR)technique is first adopted to form TRTWTHR.However.unreasonable metal streamlines(UMS)and uncoordinated growth of three ribs easily occur in CRR of TRTWTHR,which makes the forming quality of TRTWTHR difficult to be controlled.Faced with this difficulty,an analytical model that can predict UMS and the height of three ribs in CRR of TRTWTHR is established so as to guide the process design of CRR.Subsequently,the reliability of the established analytical model and the feasibility of CRR of TRTWTHR are confirmed by FE simulation and experiment.Then,using the established analytical model,the window of UMS occurring relevant to the tapered angle of TRTWTHR and the location of the rib of middle end is developed.Finally,three uncoordinated growth modes among three ribs are found when the width of three ribs is identical and UMS do not occur,and the mechanisms of three uncoordinated growth modes are revealed.

关键词： Analytical model Constraining ring rolling Growth of three ribs Metal streamlines Tapered ring with thin wall and three high ribs

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机器人辅助人工髋膝关节置换手术是必然趋势

中华医学杂志 2022年第1期102卷 4-8页

作者：田华北京大学第三医院骨科骨与关节精准医学教育部工程研究中心北京100191

人工髋、膝关节置换是骨科领域最成功的手术之一,能有效缓解疼痛、矫正畸形和改善功能,从而提高患者整体生活质量。尽管髋、膝关节置换是目前治疗晚期髋、膝疾患的常规手术,但依然存在着术后肢体不等长、脱位或不稳定、跛行和不明原因... 详细信息

人工髋、膝关节置换是骨科领域最成功的手术之一,能有效缓解疼痛、矫正畸形和改善功能,从而提高患者整体生活质量。尽管髋、膝关节置换是目前治疗晚期髋、膝疾患的常规手术,但依然存在着术后肢体不等长、脱位或不稳定、跛行和不明原因疼痛等并发症。这些并发症的发生很大程度上与假体安放的位置相关。机器人辅助进行髋、膝关节置换手术的优势不仅在于术前可进行三维手术规划,而且手术过程中机械臂能够辅助完美实现术前规划,避免了人为误差。目前的关节置换机器人依然存在着不能进行个性化手术规划、手术时间长效率低、价格昂贵等问题,但相信在人工智能加持和算法的不断优化下,人工关节置换机器人将会越来越精准化、智能化和微创化,这是关节外科未来发展的必然趋势。

关键词：关节成形术机器人辅助手术髋关节置换术膝关节置换术

An innovative constraining ring rolling process for manufacturing conical rings with thin sterna and high ribs

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Chinese Journal of Aeronautics 2022年第8期35卷 324-339页

作者： Duanyang tian Xinghui HAN Lin hua Xuan HU Hubei Key Laboratory of Advanced Technology for Automotive Components Wuhan University of TechnologyWuhan 430070 China School of Automotive Engineering Wuhan University of TechnologyWuhan 430070China

Conical rings with thin sterna and high ribs(CRTSHR)are key bearing-load parts of aerospace equipment,which are required to be manufactured with high performance and efficiency.Traditional ring rolling is the most preferred method for manufacturing high-performance ring parts,but it can hardly achieve the forming of CRTSHR due to the extreme geometry of CRTSHR.To solve this difficulty,an innovative constraining ring rolling process(CRR)is proposed in this paper to manufacture CRTSHR.To evaluate the proposed CRR and reveal its deformation behaviors,a thermomechanical coupled FE model for CRR of CRTSHR is established.Then,the experiment for CRR of CRTSHR is performed on a modified ring rolling machine,which proves that CRR of CRTSHR is feasible and the established FE model is reliable.Based on the reliable FE model,the metal flow mode in deformed CRTSHR is analyzed,and the deformation characteristics such as the stress state,strain distribution and the evolution of power parameters in CRR of CRTSHR are revealed.Finally,the influences of key parameters such as the friction factor between ring and molds,the diameter of idle roll and the feed velocity of idle roll on CRR of CRTSHR are investigated by FE simulation.

关键词： Conical rings with thin sterna and high ribs Deformation characteristics FE simulation Metal flow Ring rolling

Diagnosis and Design Improvement of the Internal Flow Field in an Automotive Cooling Fan Based on Boundary Vorticity Dynamics, Part Ⅰ: Blade Profile Scaling and Rotation

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Journal of Thermal Science 2022年第6期31卷 2411-2423页

作者： PENG Zhigang OUYANG hua WU Yadong tian Jie School of Mechanical Engineering Shanghai Jiao Tong UniversityShanghai 200240China Shanghai Brose Electric Motors Company Limited Shanghai 201801China

To optimize the aerodynamic performance of the automobile cooling fan(ACF), the internal flow field of the original fan was numerically simulated. According to the theory of boundary vorticity dynamics(BVD), the distribution laws of the boundary vorticity flux(BVF) on the blade surface and the circumferential vorticity(CV) at the wake plane of the fan were analyzed, and the underlying various negative factors, such as vortex shedding, separated flow and complicated secondary flow, on the fan blade surface and its dynamic source were diagnosed. Combined with the velocity triangle theory, the mathematical relationship between the BVF diagnosis and the geometrical characteristics of the blade profile(hereinafter referred to as profile) is used to guide the design improvement of the blade. The analysis found that at the same speed, the extension and rotation of the profile could match a smaller input torque at the same flow rate and pressure rise, thereby improving the efficiency of the fan. The test results confirmed the above conclusion. The peak efficiency of the improved fan has been increased by 2.3%, and the aerodynamic performance in the low-flow-rate has been improved. The conclusion of the study shows the applicability of the BVD theory in the diagnosis and design improvement of ACF internal flow.

关键词： boundary vorticity flux automotive cooling fan design improvement blade profile

Modal Analysis of Axial Compressor Tip Rotating Instability under Varying Operating Conditions

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Journal of Thermal Science 2023年第4期32卷 1345-1356页

作者： LI Tao WU Yadong tian Jie OUYANG hua School of Mechanical Engineering Shanghai Jiao Tong UniversityShanghai200240China Engineering Research Centre of Gas Turbine and Civil Aero Engine Ministry of EducationShanghai Jiao Tong UniversityShanghai200240China

The full annulus numerical research was performed on a low-speed compressor rotor to investigate the rotating instability in the tip region.The frequency spectra show the existence of rotating instability at narrow stable operating range.With the decrease of flow rate,31 cells of flow disturbance can be found in the instantaneous flow field.The distribution of vortex suggests that the circumferential propagation of the interaction between tip leakage vortex and adjacent blade brings about these cells.The dynamic mode decomposition(DMD)method and spatial discrete Fourier transform(SDFT)were applied to obtain the circumferential mode features,and the results indicate that the rotating instability is associated with the 31 cells of flow disturbance.Then the DMD method was further applied on the pressure data from a circle and an annulus domain,so as to extract different mode components with the corresponding spatial structures,frequencies and amplitudes.The results suggest that DMD modes can display the flow feature and explore the evolution of each instability source in the tip flow field.

关键词： axial compressor rotating instability flow structure circumferential mode dynamic mode decomposition

Study of DDT and its derivatives DDD, DDE adsorption and degradation over Fe-SBA-15 at low temperature

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Journal of Environmental Sciences 2012年第3期24卷 536-540页

作者： Hailin Wang Hua Tian Zhengping Hao Research Center for Eco-Environmental Sciences Chinese Academy of SciencesBeijing 100085China Institute of Physics and Chemistry Chinese Academy of SciencesBeijing 100190China

Mesoporous SBA-15 with different Fe2O3 loading were synthesized by an in-situ coating progress for removals of dichlorodiphenyl- trichloroethane （DDT） and its derivatives, i.e., 1,1-dichloro-2,2-bis-（p-chlorophenyl）ethane （DDD） and 1,1-dichloro-2,2-bis-（4-chloro -phenyl） ethane （DDE）. The results from XRD （X-ray diffractometer）, TEM （transmission electron microscopy） indicated that the iron could be well dispersed on SBA-15 within 6 wt.% Fe2O3 loading. Nitrogen adsorption-desorption tests indicated that the synthesized materials were characterized by ordered meso-structure, high surface area and large pore volume. DDTs were removed from aqueous media in 12-hr treatment and high removal efficiency of DDTs was achieved at over 94%. DDTs could be completely degraded at 350°C under the existence of SBA-15 with 4 wt.% Fe2O3 loading. The final degradation products of DDT were dichlorobenzophenone （DCB） and bis-（4-chloro-phenyl） methane （DDM）, suggesting a complete dechlorination from trichloromethyl.

关键词： DDTs SBA-15 iron adsorption catalytic dechlorination