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Design method and experimental study of a cathode tool with an extremely high leveling ratio for electrochemical machining of blisk

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Chinese Journal of Aeronautics 2024年第4期37卷 593-608页

作者： Moqi SHEN Jia LIU Jingtao WANG di zhu College of Mechanical and Electrical Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China

To obtain final parts with the desired dimensional accuracy and repeatability via electrochemical machining(ECM), the machining process must enter an ECM balanced state. However,for the ECM processing of blisk, a key component of aerospace engines, the surface of the blade blank often has an uneven allowance distribution due to the narrow passage of the cascade. It is difficult to remedy this issue in subsequent processing steps, which is necessary to ensure the dimensional accuracy and repeatability of the final blade profile. To solve this problem, electrolytic machining must be preceded by electrolytic shaping, which requires cathode tools with large leveling ratios to quickly homogenize the blank surface of the blade. In this study, to obtain a cathode tool with an extremely high leveling ratio, a design method based on the variation in the electrode gap in the non-equilibrium electrolytic state is proposed, and a dissolution model based on the nonequilibrium state is established. In this design method, the allowance on the blank to be machined is first divided into many discrete allowances with the normal direction. The initial machining clearance, feed rate, and total machining time are then calculated using classical ECM equilibrium state theory based on the maximum allowance. Meanwhile, the point coordinates of the cathode tool at maximum allowance can be determined. The non-equilibrium model can then be used to calculate the relative coordinate positions corresponding to the remaining discrete allowances. Finally, the entire cathode tool profile is designed. Simulations, fundamental experiments, and blisk unit workpiece experiments were carried out to validate the design approach. In the simulated processing of the plane workpiece, the leveling ratio of the cathode tool designed by the proposed method(0.77)was 83% higher than that of the cathode tool designed using the traditional method. The simulation results were confirmed by processing experiments. In the machining of blisk unit workpieces with compl

关键词： Electrochemical machining(ECM) Non-equilibrium machining Large leveling ratios Cathode design Finite element simulation Blisk

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Silencing of Jumonji domain-containing 1C inhibits the osteogenic differentiation of bone marrow mesenchymal stem cells via nuclear factor-κB signaling

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World Journal of Stem Cells 2024年第2期16卷 151-162页

作者： Jing-Yi Li Ting-Ting Wang Li Ma Yu Zhang di zhu Department of Medical Cosmetology Beijing Tiantan HospitalCapital Medical UniversityBeijing 100070China Department of General Gerontology The First Affiliated Hospital of Zhengzhou UniversityZhengzhou 450052Henan ProvinceChina Department of Plastic Surgery China-Japan Friendship HospitalBeijing 100029China Senior Department of Hematology The Fifth Medical CentreGeneral Hospital of Chinese People’s Liberation ArmyBeijing 100071China Department of Orthopaedic Surgery Beijing Tiantan HospitalCapital Medical UniversityBeijing 100070China

BACKGROUND Osteoporosis is a common metabolic bone disorder induced by an imbalance between osteoclastic activity and osteogenic activity.During osteoporosis,bone mesenchymal stem cells(BMSCs)exhibit an increased ability to differentiate into adipocytes and a decreased ability to differentiate into osteoblasts,resulting in bone loss.Jumonji domain-containing 1C(JMJD1C)has been demonstrated to suppress osteoclastogenesis.AIM To examine the effect of JMJD1C on the osteogenesis of BMSCs and the potential underlying mechanism.METHODS BMSCs were isolated from mouse bone marrow tissues.Oil Red O staining,Alizarin red staining,alkaline phosphatase staining and the expression of adipo-genic and osteogenic-associated genes were assessed to determine the differen-tiation of BMSCs.Bone marrow-derived macrophages(BMMs)were incubated with receptor activator of nuclear factor-kappaΒligand to induce osteoclast differentiation,and osteoclast differen-tiation was confirmed by tartrate-resistant acid phosphatase staining.Other related genes were measured via reverse transcription coupled to the quantitative polymerase chain reaction and western blotting.Enzyme-linked immunosorbent assays were used to measure the levels of inflammatory cytokines,including tumor necrosis factor alpha,interleukin-6 and interleukin-1 beta.RESULTS The osteogenic and adipogenic differentiation potential of BMSCs isolated from mouse bone marrow samples was evaluated.JMJD1C mRNA and protein expression was upregulated in BMSCs after osteoblast induction,while p-nuclear factor-κB(NF-κB)and inflammatory cytokines were not significantly altered.Knockdown of JMJD1C repressed osteogenic differentiation and enhanced NF-κB activation and inflammatory cytokine release in BMSCs.Moreover,JMJD1C expression decreased during BMM osteoclast differentiation.CONCLUSION The JMJD1C/NF-κB signaling pathway is potentially involved in BMSC osteogenic differentiation and may play vital roles in the pathogenesis of osteoporosis.

关键词： Osteoporosis Mesenchymal stem cells Osteogenesis Jumonji domain-containing 1C Nuclear factor-κB

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Bioinspired Stretchable MXene Deformation-Insensitive Hydrogel Temperature Sensors for Plant and Skin Electronics

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Research 2024年第1期2023卷 389-401页

作者： Jun Wu Yinghui Li Shengshun Duan Zhehan Wang Xu Jing Yucheng Lin di zhu Wei Lei Qiongfeng Shi Li Tao Joint International Research Laboratory of Information display and Visualization School of Electronic Science and EngineeringSoutheast UniversityNanjingJiangsu 210096China School of Materials Science and Engineering Southeast UniversityNanjingJiangsu 210096China Center of 2D Materials and Devices Southeast UniversityNanjingJiangsu 210096China

Temperature sensing is of high value in the wearable healthcare,robotics/prosthesis,and noncontact physiological monitoring.However,the common mechanic deformation,including pressing,bending,and stretching,usually causes undesirable feature size changes to the inner conductive network distribution of temperature sensors,which seriously influences the accuracy.Here,inspired by the transient receptor potential mechanism of biological thermoreceptors that could work precisely under various skin contortions,we propose an MXene/Clay/poly(N-isopropylacrylamide)(PNIPAM)(MCP)hydrogel with high stretchability,spike response,and deformation insensitivity.The dynamic spike response is triggered by the inner conductive network transformation from the 3-dimensional structure to the 2-dimensional surface after water being discharged at the threshold temperature.The water discharge is solely determined by the thermosensitivity of PNIPAM,which is free from mechanical deformation,so the MCP hydrogels can perform precise threshold temperature(32℃)sensing under various deformation conditions,i.e.,pressing and 15%stretching.As a proof of concept,we demonstrated the applications in plant electronics for the real-time surface temperature monitoring and skin electronics for communicating between human and machines.Our research opens venues for the accurate temperature-threshold sensation on the complicated surface and mechanical conditions.

关键词： stretching proof precise

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A pilot study of the differentiated landscape of peripheral blood mononuclear cells from children with incomplete versus complete Kawasaki disease

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World Journal of Pediatrics 2024年第2期20卷 189-200页

作者： Shu-Na Sun Yan Zhou Xing Fu Yuan-Zheng Zheng Cao Xie Guo-You Qin Fang Liu Chen Chu Feng Wang Cheng-Long Liu Qing-Tong Zhou De-Hua Yang di zhu Ming-Wei Wang Yong-Hao Gui Children's Hospital of Fudan University National Children's Medical CenterShanghai 201102China The National Center for Drug Screening Shanghai Institute of Materia MedicaChinese Academy of SciencesShanghai 201203China Accuramed Technology(Shanghai)Ltd. Shanghai 200233China School of Pharmacy Fudan UniversityShanghai 201203China School of Public Health Fudan UniversityShanghai 200032China Department of Pharmacology School of Basic Medical SciencesFudan UniversityShanghai 200032China Research Center for Deepsea Bioresources Sanya 572025China Department of Chemistry School of ScienceThe University of TokyoTokyo 113-0033Japan School of Pharmacy Hainan Medical UniversityHaikou 570288China

Kawasaki disease(KD)is a disorder of immune responses.The prevalence of KD among 100,000 children aged 0-4 years was 71.9-110.0 in China,170.9-194.9 in Korea,and 18.1-21.3 in the USA[1].The most severe complication of KD is coronary artery lesions(CALs),including coronary dilatation and coronary aneurysms,which may even lead to myocardial ischemia,myocardial infarction,and sudden death.

关键词： coronary ischemia differentiated

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Flow field design and experimental investigation of electrochemical machining on blisk

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Chinese Journal of Aeronautics 2022年第8期35卷 295-303页

作者： Jianwei GUO Dong zhu di zhu College of Mechanical and Electrical Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China

Flow field is a crucial factor to influence the stability and surface quality in the electrochemical machining(ECM)of blisks.A four-way flow mode was proposed to eliminate mixing regions of electrolyte at the leading and tailing edges.Two flow field models were described separately in this report:a W-shaped flow mode and a four-way flow mode.The flow field was analyzed through a finite element method.The results showed that,in comparison with the W-shaped flow mode,the distribution of electrolyte flow was more uniformed and the mixed region in the flow channel was improved.The pressure of the leading and tailing edges inlets was optimized,and optimal pressure of 0.6 MPa was determined.In addition,verification experiments were performed,and the results showed that the stability,efficiency,and quality of the profiles of the blisk blade manufactured by ECM were enhanced in the new flow mode.

关键词： Blisk Electrochemical machining Electrolyte Flow field Surface quality

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Improving profile accuracy and surface quality of blisk by electrochemical machining with a micro inter-electrode gap

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Chinese Journal of Aeronautics 2023年第4期36卷 523-537页

作者： Jingtao WANG Zhengyang XU di zhu College of Mechanical and Electrical Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China

Electrochemical machining(ECM)has emerged as an important option for manufacturing the blisk.The inter-electrode gap(IEG)distribution is an essential parameter for the blisk precise shap-ing process in ECM,as it affects the process stability,profile accuracy and surface quality.Larger IEG leads to a poor localization effect and has an adverse influence on the machining accuracy and surface quality of blisk.To achieve micro-IEG(ding/trailing edges was limited to within 91 ***-pared with the currently-established process,the profile accuracy of the blade’s concave and convex profiles was improved by 50.5%and 53.3%,respectively.The surface quality was improved by 53.2%and 50.9%,respectively.Additionally,the machined surface was covered with small corrosion pits and weak attacks of the grain boundary due to selective dissolution.Some electrolytic products were dispersed on the machined surface,and their components were mainly composed of the carbide and oxide products of Ti and Nb elements.The results indicate that the variable-parameters strategy is effective for achieving a tiny IEG in blisk ECM,which can be used in engineering practice.

关键词： Electrochemical machining Blisk IEG Machining quality Surface quality

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Cobalt-Catalyzed Enantioselective Ring-Opening Reactions of Oxa- and Aza-bicyclic Alkenes with Alkenylboronic Acids

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Chinese Journal of Chemistry 2022年第2期40卷 190-194页

作者： di zhu Yongmei Zhao Qinglei Chong Fanke Meng State Key Laboratory of Heavy Oil Processing College of ScienceChina University of PetroleumBeijing 102249China State Key Laboratory of Organometallic Chemistry Center for Excellence in Molecular SynthesisShanghai Institute of Organic ChemistryChinese Academy of Sciences345 Lingling RoadShanghai 200032China

Catalytic enantioselective ring-opening of oxa-and aza-bicyclic alkenes with readily available accessible alkenylboronic acids,promoted by a chiral phosphine-Co complex,is reported.Such a process represents the unprecedented Co-catalyzed introduction of various alkenyl groups onto the oxa-and aza-bicyclic alkenes,affording a wide range of multisubstituted functionalized cyclohexenes in up to 98%yield and 99.5:0.5 er.

关键词： Cobalt Ring-opening Enantioselective catalysis Bicyclic alkene Alkenylboron

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Design and optimization of electrolyte flow fields in electrochemical machining of cross-channel array with tool vibration

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Chinese Journal of Aeronautics 2022年第4期35卷 461-472页

作者： Yan LIU Jia LIU di zhu Hao WANG College of Mechanical and Electrical Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China

A metallic interconnect plate with a flow channel array is one of the most important elements in a solid oxide fuel cell(SOFC). Electrochemical machining(ECM) is considered to be an adoptable technology for fabricating flow channels in an interconnect plate on account of its efficiency and low cost. With respect to the traditional electrolyte flow mode in ECM cross-channel array, the electrolyte usually flows from one side to the opposite side of the rectangular processing area. However, obvious flow marks are typically formed at the bottom of channels perpendicular to the flow. According to multiphysical simulation analysis, the low electrolyte velocity in the channels perpendicular to the flow leads to uneven distribution of electrolyte products. To improve the uniformity of the flow field, two new electrolyte flow modes, “two-in and two-out” and “three-in and one-out”, are proposed. By adding one or two additional electrolyte inlets to the sides of the traditional flow field, the electrolyte flow velocity in the channels perpendicular to the traditional flow will be increased. Corresponding simulations and experiments were performed and the results showed that the “three-in and one-out” flow mode can produce a flatter bottom surface for the cross-channel array. Parameter optimization experiments for the preferred flow mode were undertaken and the optimal flow field parameters were determined.

关键词： Cross-channel array Dynamic simulation Electrochemical machining Flow field Interconnect plate

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Electrochemical drilling of small holes by regulating in real-time the electrolyte flowrate in multiple channels

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Chinese Journal of Aeronautics 2022年第5期35卷 470-483页

作者： Jinxing LUO Xiaolong FANG Tao YANG di zhu National Key Laboratory of Science and Technology on Helicopter Transmission Nanjing University of Aeronautics and AstronauticsNanjing 210016China Jiangsu Key Laboratory of Precision and Micro-Manufacturing Technology Nanjing University of Aeronautics and AstronauticsNanjing 210016China

Electrochemical drilling(ECD)provides an alternative technique for drilling multiple small holes in difficult-to-machine materials in numerous industrial applications such as for aeroengines.The value and fluctuation of electrolyte flowrate can seriously affect the machining stability and hole quality in ECD.In particular,when drilling multiple holes,the distribution and fluctuations of the electrolyte flowrate in each channel could influence the uniformity of the electrolyte flowrate among multiple tube electrodes,thereby affecting the machining stability and the maximum feed rate.Thus,an eight-channel flow control system was developed to measure and regulate in real time the electrolyte flowrate supplied into each individual tube electrode.This paper proposes ECD of small holes with real-time flowrate control to improve the uniformity of electrolyte flowrate in each tube electrode and reduce the fluctuations in the electrolyte flowrate.In single-hole drilling,when the electrolyte flowrate was regulated in real time,the hole quality and machining stability were considerably better than without regulation.This is because the electrolyte flowrate remains basically constant,which stabilizes the flow field.Moreover,by considering the hole profile,it was found that an electrolyte flowrate of 200.0 m L/min can be acceptable for ECD of small holes.When the eight-channel flow control system was used in multiple-hole drilling,the uniformity of the electrolyte flowrate in each tube electrode was obviously improved,which led to a more stable process.Additionally,the maximum feed rate can attain 2.40 mm/min in multiple-hole drilling.Based on these findings,a matrix(5×32)of multiple small holes was successfully fabricated with a satisfactory diameter consistency,as the machining stability and machining efficiency had been enhanced.

关键词： Electrochemical drilling Small holes Electrolyte flowrate Real-time regulation Machining stability

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Investigation of anode shaping process during co-rotating electrochemical machining of convex structure on inner surface

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Chinese Journal of Aeronautics 2023年第7期36卷 489-504页

作者： Shuofang ZHOU Dengyong WANG Wenjian CAO di zhu College of Mechanical and Electrical Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China Jiangsu Key Laboratory of Precision and Micro-Manufacturing Technology Nanjing 210016China

A novel co-rotating electrochemical machining method is proposed for fabricating convex structures on the inner surface of a revolving part.The electrodes motion and material removal method of co-rotating electrochemical machining are different from traditional electrochemical machining.An equivalent kinematic model is established to analyze the novel electrodes motion,since the anode and cathode rotate in the same direction while the cathode simultaneously feeds along the line of centres.According to the kinematic equations of the electrodes and Faraday’s law,a material removal model is established to simulate the evolution of the anode profile in co-rotating electrochemical machining.The simulation results indicate that the machining accuracy of the convex structure is strongly affected by the angular velocity ratio and the radius of the cathode tool.An increase of the angular velocity ratio can improve the machining accuracy of a convex structure.A small difference in the radius of the cathode tool will cause changes in the shape of the sidewalls of the convex structure.The width of the cathode window affects only the width of the convex structure and the inclination a of the sidewall.A relation between the width of the cathode window and the width of the convex structure was obtained.The formation process for a convex structure under electrochemical dissolution was revealed.Based on the simulation results,the optimal angular velocity ratio and cathode radius were selected for an experimental verification,and 12 convex structures were simultaneously fabricated on the inner surface of a thin-walled revolving part.The experimental results are in good agreement with the simulation results,which verifies the correctness of the theoretical analysis.Therefore,inner surface co-rotating electrochemical machining is an effective method for fabricating convex structures on the inner surface of a revolving part.

关键词： Convex structure forming process Co-rotating motion Current density Electrochemical machining Revolving part

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