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Accuracy evaluation for in-situ machining reference points binocular measurement based on credibility probability

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Chinese Journal of Aeronautics 2024年第1期37卷 472-486页

作者： Binchao YU Wei LIU Yanze ZHANG Dazhi MA Zhenyuan JIA Yi YUE Jiabo ZHANG key laboratory for precision and non-traditional machining Technology of the ministry of education Dalian University of TechnologyDalian 116024China Beijing Spacecrafts China Academy of Space TechnologyBeijing 100081China

Passive binocular measurement systems are being increasingly utilized in the in-situ industries of automobiles,aviation,and aerospace,etc.due to their excellent qualities of accuracy,efficiency,and cost performance.Whereas the barrier of evaluating the accuracy of measured objects resulted from the unequal equivalent focal length and quantization of pixels,has limited their further development and application of high requirements for in-situ machining,e.g.,the measurement of machining reference points for the positioning of robotic drilling in aerospace manufacturing.In this paper,an accuracy evaluation method is proposed to address the problem.Firstly,the unequal equivalent focal length is considered to improve the accuracy of 3D reconstruction.Next,the credibility probability model is developed to calculate the probability of the observed error in the public view of the binocular measurement system and indicates the direction of improvement.Finally,the in-situ experiment is carried out to validate the method within the effective public view range of 300 mm×300 mm.The experiment results show that the RMSs of observed errors are superior to 0.035 mm,and the credibility probabilities are all higher than 0.91;the maximum 3D reconstruction accuracy improvement is 60.3%,with the error reduced from 0.078 mm to 0.031 mm.

关键词： Aerospace manufacturing Binocular vision Credibility probability Pixel quantization Unequal equivalent focal length

Damage mechanisms during lapping and mechanical polishing CdZnTe wafers

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Rare Metals 2010年第3期29卷 276-279页

作者： LI Yan,KANG Renke,GAO Hang,and WU Dongjiang key laboratory for precision and non-traditional machining Technology (ministry of education),Dalian University of Technology,Dalian 116024,China key laboratory for precision and non-traditional machining Technology (ministry of education) Dalian University of Technology Dalian China

CdZnTe wafers were machined by lapping and mechanical polishing processes,and their surface and subsurface damages were investigated.The surface damages are mainly induced by three-body abrasive wear and embedded abrasive wear during lapping process.A new damage type,which is induced by the indentation of embedded abrasives,is found in the subsurface.When a floss pad is used to replace the lapping plate during machining,the surface damage is mainly induced by two-body abrasive and three-body abrasive wear,and the effect of embedded abrasives on the surface is greatly weakened.Moreover,this new damage type nearly disappears on the subsurface.

关键词： lapping mechanical polishing wafers surface subsurface abrasive

3D Evaluation Method of Cutting Surface Topography of Carbon / Phenolic (C/Ph) Composite

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Journal of Wuhan University of Technology(Materials Science) 2011年第3期26卷 459-463页

作者：周鹏 key laboratory for precision and non-traditional machining Technology of ministry of education Dalian University of Technology

3D evaluation method of cutting surface topography for C/Ph composites was established.The cutting surface was measured by Talyscan 150,using 3D non-contact measurement.Through the results of 2D and 3D roughness evaluating for C/Ph composite and Duralumin,the 2D evaluation method of the cutting surface topography of C/Ph composite loses a lot of information,the characteristics of the surface topography of C/Ph composite can be comprehensively and authentically evaluated only by 3D evaluation method.Furthermore,3D amplitude and spatial parameters were adopted to evaluate the surface.The results show that： the topography of the C/Ph composite is anisotropic,there are more valleys in the machined surface of C/Ph than that of duralumin,and there are not obvious feeding textures for C/Ph,which indicates the machining mechanism is different from the metal.In conclusion,the topography of the C/Ph composite cutting surface is anisotropic;the cutting surface of C/Ph composite needs 3D evaluation method.

关键词： C/Ph composite surface topography 3D evaluation method

Mechanism of nanoparticle aggregation in gas-liquid microfluidic mixing

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Chinese Chemical Letters 2024年第4期35卷 376-381页

作者： Hongxia Li Xiyang Wang Du Qiao Jiahao Li Weiping Zhu Honglin Li key laboratory for precision&non-traditional machining Technology of ministry of education Dalian University of TechnologyDalian 116023China Shanghai key laboratory of New Drug Design School of PharmacyEast China University of Science and TechnologyShanghai 200237China

Using gas-liquid segmented micromixers to prepare nanoparticles that have a homogeneous particle size, controllable shape, and monodispersity advantages. Although nanoparticle aggregation within a microfluid has been shown to be affected by the shear effect, the shear effect triggering conditions in gasliquid two-phase flow is unclear and the aggregation behavior of nanoparticles under the shear effect is difficult to predict, resulting in uncontrollable physical and chemical properties of nanoparticle aggregates. In this study, a numerical simulation of nanoparticle aggregation in gas-liquid two-phase flow under the shear effect is performed using the CFD-DEM method. Then, the effects of total flow rate,gas-liquid two-phase flow ratio, and particle volume fraction on particle aggregation were analyzed to achieve control of particle aggregation shape and size. Meanwhile, the triggering mechanism of the shear effect and the mechanism of the shear effect on the aggregation of nanoparticles were clarified. The results show that increasing the total flow rate or decreasing the gas-liquid two-phase flow rate ratio can induce the shear effect, which reduces the particle aggregation size and makes the morphology tend to be spherical. Moreover, increasing the particle volume fraction, and total flow rate or decreasing the gas-liquid two-phase flow rate ratio also increases the number of particle collisions and induce interparticle adhesion. Hence, particle adhesion and the shear effect compete with each other and together affect particle aggregation.

关键词： Microfluidic Gas-liquid segmented micromixer Nanoparticle aggregation Shear effect Numerical calculation

Microfluidic separation of particles by synergistic effect of geometry-induced hydrodynamics and magnetic field

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Chinese Chemical Letters 2024年第2期35卷 380-385页

作者： Du Qiao Hongxia Li Weiping Zhu Lili Zhu Danyang Zhao Honglin Li key laboratory for precision & non-traditional machining Technology of ministry of education Dalian University of TechnologyDalian 116023China Shanghai key laboratory of New Drug Design School of PharmacyEast China University of Science and TechnologyShanghai 200237China Lingang Lab Shanghai 200031China

Microfluidic combined with magnetic field have been demonstrated to be the promising solutions for fast and low-damage particles separation.However,the difficulties in the precise layout of magnets and accurate prediction of particle trajectories lead to under and over separation of target particles.A novel particle separation lab-on-chip(LOC)prototype integrated with microstructures and micropolar arrays is designed and characterized.Meanwhile,a numerical model for the separation of magnetic particles by the synergistic effect of geometry-induced hydrodynamics and magnetic field is constructed.The effect of geometry and magnetic field layout on particle deflection is systematically analyzed to implement accurate prediction of particle trajectories.It is found that the separation efficiency of magnetic particles increased from 50.2%to 91.7%and decreased from 88.6%to 85.7%in the range of depth factors from 15µm to 27µm and width factors from 30µm to 60µm,respectively.In particular,the combined effect of the offset distance of permanent magnets and the distance from the main flow channel exhibits a significant difference from the conventional perception.Finally,the developed LOC prototype was generalized for extension to arbitrary systems.This work provides a new insight and robust method for the microfluidic separation of magnetic particles.

关键词： Microfluidic Particle separation Synergistic effect Hydrodynamics Magnetic field Numerical calculation

Ultrafast micro/nano-manufacturing of metastable materials for energy

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National Science Review 2024年第4期11卷 283-298页

作者： Xiaoya Cui Yanchang Liu Yanan Chen School of Materials Science and Engineering Key Laboratory of Advanced Ceramics and Machining Technology(Ministry of Education) and Tianjin Key Laboratory of Composite and Functional MaterialsTianjin University ministry of education key laboratory of Protein Sciences School of Life SciencesTsinghua University

The structural engineering of metastable nanomaterials with abundant defects has attracted much attention in energy-related fields. The high-temperature shock(HTS) technique, as a rapidly developing and advanced synthesis strategy, offers significant potential for the rational design and fabrication of high-quality nanocatalysts in an ultrafast, scalable, controllable and eco-friendly way. In this review, we provide an overview of various metastable micro-and nanomaterials synthesized via HTS, including single metallic and bimetallic nanostructures, high entropy alloys, metal compounds(e.g. metal oxides) and carbon nanomaterials. Note that HTS provides a new research dimension for nanostructures, i.e. kinetic modulation. Furthermore, we summarize the application of HTS—as supporting films for transmission electron microscopy grids—in the structural engineering of 2D materials, which is vital for the direct imaging of metastable materials. Finally, we discuss the potential future applications of high-throughput and liquid-phase HTS strategies for non-equilibrium micro/nano-manufacturing beyond energy-related fields.It is believed that this emerging research field will bring new opportunities to the development of nanoscience and nanotechnology in both fundamental and practical aspects.

关键词： high-temperature shock technique defect engineering metastable phase kinetic modulation non-equilibrium micro/nano-manufacturing

Research on Discharging Mechanism of Powder Mixed EDM

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武汉理工大学学报 2006年第S2期28卷 417-422页

作者： WANG Yuangang ZHAO Fuling (key laboratory for precision and non.traditional machining Technology of ministry of education,Dalian University of Technology,Dalian 116024,China key laboratory for precision and non-traditional machining Technology of ministry of education Dalian University of TechnologyDalian 116024China

This paper presents investigations on discharging mechanism in powder mixed EDM.By analyzing the inception, growth of electrical tree and the ignition of discharges in liquid filled gap,the whole discharging process is proposed.It is explored that the reason of modification of ignition behaves by adding fine particle powders of metal or semiconductor to the working liquid.

关键词： PMEDM electrical tree discharge breakdown mechanism

Large area mold fabrication for the nanoimprint lithography using electron beam lithography

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Science China(Technological Sciences) 2010年第1期53卷 248-252页

作者： CHU JinKui1,2,MENG FanTao1,2,HAN ZhiTao1,2 & GUO Qing1,2 1 key laboratory for Micro/Nano Technology and System of Liaoning Province,Dalian University of Technology,Dalian 116024,China 2 key laboratory for precision and non-traditional machining Technology of ministry of education,Dalian University of Technology,Dalian 116024,China key laboratory for Micro/Nano Technology and System of Liaoning Province Dalian University of Technology Dalian China key laboratory for precision and non-traditional machining Technology of ministry of education Dalian University of Technology Dalian China

The mold fabrication is a critical issue for the development of nanoimprint lithography as an effective low-cost and mass production process.This paper describes the fabrication process developed to fabricate the large area nanoimprint molds on the silicon wafers.The optimization of e-beam exposure dose and pattern design is presented.The overlayer process is developed to improve the field stitching accuracy of e-beam exposure,and around 10 nm field stitching accuracy is obtained.By means of the optimization of the e-beam exposure dose,pattern design and overlayer process,large area nanoimprint molds having dense line structures with around 10 nm field stitching accuracy have been fabricated.The fabricated mold was used to imprint commercial imprinting resist.

关键词： nanoimprint lithography mold fabrication electron beam lithography

Selective type II TRK inhibitors overcome xDFG mutation mediated acquired resistance to the second-generation inhibitors selitrectinib and repotrectinib

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Acta Pharmaceutica Sinica B 2024年第2期14卷 517-532页

作者： Shuang Xiang Xiaoyun Lu International Cooperative laboratory of traditional Chinese Medicine Modernization and Innovative Drug Discovery of Chinese ministry of education(MOE) Guangdong Provincial Key Laboratory of New Drug Design and EvaluationGuangzhou City Key Laboratory of Precision Chemical Drug DevelopmentSchool of PharmacyJinan UniversityGuangzhou 510632China

Neurotrophic receptor kinase(NTRK) fusions are actionable oncogenic drivers of multiple pediatric and adult solid tumors,and tropomyosin receptor kinase(TRK) has been considered as an attractive therapeutic target for "pan-cancer" harboring these fusions.Currently,two generations TRK inhibitors have been developed.The representative second-generation inhibitors selitrectinib and repotrectinib were designed to overcome clinic acquired resistance of the first-generation inhibitors larotrectinib or entrectinib resulted from solvent-front and gatekeeper on-target mutations.However,xDFG(TRKAG667C/A/S,homologous TRKCG696C/A/S) and some double mutations still confer resistance to selitrectinib and repotrectinib,and overcoming these resistances represents a major unmet clinical need.In this review,we summarize the acquired resistance mechanism of the first-and second-generation TRK inhibitors,and firstly put forward the emerging selective type Ⅱ TRK inhibitors to overcome xDFG mutations mediated resistance.Additionally,we concluded our perspectives on new challenges and future directions in this field.

关键词： NTRK fusions TRK kinase Clinical resistance xDFG mutations Selective type II inhibitors