The increasing demand for high-end equipment in crucial sectors such as aerospace,aeronautics, energy, power, information and electronics continues growing. However, the manufacturing of such advanced equipment poses ...The increasing demand for high-end equipment in crucial sectors such as aerospace,aeronautics, energy, power, information and electronics continues growing. However, the manufacturing of such advanced equipment poses significant challenges owing to high-level requirements for loading, transmission, conduction, energy conversion, and stealth. These challenges are amplified by complex structures, hard-to-cut materials, and strict standards for surface integrity and precision. To overcome these barriers in high-end equipment manufacturing, high-performance manufacturing(HPM) has emerged as an essential solution.This paper firstly discusses the key challenges in manufacturing technology and explores the essence of HPM, outlining a quantitative relationship between design and manufacturing.Subsequently, a generalized framework of HPM is proposed, accompanied by an in-depth exploration of the foundational elements and criteria. Ultimately, the feasible approaches and enabling technologies, supported by the analysis of two illustrative case studies are demonstrated. It is concluded that HPM is not just a precision and computational manufacturing framework with a core focus on multiparameter correlation in design, manufacturing, and service environments. It also represents a performance-geometry-integrated manufacturing framework for an accurate guarantee of the optimal performance.展开更多
Workpiece rotational grinding is widely used in the ultra-precision machining of hard and brittle semiconductor materials,including single-crystal silicon,silicon carbide,and gallium arsenide.Surface roughness and sub...Workpiece rotational grinding is widely used in the ultra-precision machining of hard and brittle semiconductor materials,including single-crystal silicon,silicon carbide,and gallium arsenide.Surface roughness and subsurface damage depth(SDD)are crucial indicators for evaluating the surface quality of these materials after grinding.Existing prediction models lack general applicability and do not accurately account for the complex material behavior under grinding conditions.This paper introduces novel models for predicting both surface roughness and SDD in hard and brittle semiconductor materials.The surface roughness model uniquely incorporates the material’s elastic recovery properties,revealing the significant impact of these properties on prediction accuracy.The SDD model is distinguished by its analysis of the interactions between abrasive grits and the workpiece,as well as the mechanisms governing stress-induced damage evolution.The surface roughness model and SDD model both establish a stable relationship with the grit depth of cut(GDC).Additionally,we have developed an analytical relationship between the GDC and grinding process parameters.This,in turn,enables the establishment of an analytical framework for predicting surface roughness and SDD based on grinding process parameters,which cannot be achieved by previous models.The models were validated through systematic experiments on three different semiconductor materials,demonstrating excellent agreement with experimental data,with prediction errors of 6.3%for surface roughness and6.9%for SDD.Additionally,this study identifies variations in elastic recovery and material plasticity as critical factors influencing surface roughness and SDD across different materials.These findings significantly advance the accuracy of predictive models and broaden their applicability for grinding hard and brittle semiconductor materials.展开更多
Recently,rapid and cost-effective additive manufacturing solutions for lightweight aluminum alloys with excellent high-temperature mechanical properties have been increasingly in demand.In this study,we combined laser...Recently,rapid and cost-effective additive manufacturing solutions for lightweight aluminum alloys with excellent high-temperature mechanical properties have been increasingly in demand.In this study,we combined laser-arc hybrid additive manufacturing with solution and artificial aging treatments to achieve Al-Zn-Mg-Cu alloy with favorable high-temperature strength via microstructure control.Hydrogen pores became the major defect in the as-deposited and heat-treated specimens.The continuous distribution of eutectics with hard-brittle characteristics at the grain boundaries was destructed following heat treat-ment.High-densityηprecipitates were uniformly dispersed in the heat-treated Al-Zn-Mg-Cu alloy,whereas appeared coarsened and dissolved at 473 K,owing to the rapid diffusion of Zn and Mg.The average 0.2%yield strength(318±16 MPa)and ultimate tensile strength(362±20 MPa)at 473 K af-ter heat treatment were enhanced by approximately 58%and 51%,respectively,compared to those of the as-deposited specimen.In addition,theηprecipitates contributed to lattice distortions and strain fields,which prevented dislocation motion and increased slip deformation resistance at high temper-atures.The as-deposited specimen exhibited intergranular fracture at 473 K,with cracks preferring to propagate along the aggregated eutectics.However,crack propagation proceeded in the sections with more pores in the heat-treated specimen.Our approach may provide a valid option for achieving alu-minum alloys with excellent high-temperature mechanical properties.展开更多
Water dissolution ultraprecision continuous polishing is a nontraditional machining method specifically designed for water-soluble crystals.The aim of this study is primarily to reduce the surface roughness for small ...Water dissolution ultraprecision continuous polishing is a nontraditional machining method specifically designed for water-soluble crystals.The aim of this study is primarily to reduce the surface roughness for small sizes from an experimental standpoint.A trajectory uniformity simulation analysis is carried out for a consistent material removal.A material removal model is developed based on the water dissolution principle and kinematic analysis.Numerical simulations of single-and multiple-water-core polishing trajectories are performed to explore the influences of the processing parameters such as movement form,number of water cores,speed ratio,polishing time,and period ratio on the material removal uniformity.The material removal rate is calculated according to the Preston equation.The trajectory density nonuniformity is utilized to evaluate the global uniformity of the trajectory distributions and optimize the processing parameters for a better material removal uniformity.Verification experiments are conducted on a large-size ultraprecision continuous polisher using a typical potassium dihydrogen phosphate(KDP)crystal with a water-soluble structure.The edge collapse is improved from 51.499μm to 1.477μm by trajectory uniformity optimization.The changing trends of line profile variations in the validation experiment and simulation are similar.An ultrasmooth surface of a 180 mm×180 mm KDP crystal with a surface roughness root mean square of 1.718 nm is obtained after water dissolution ultraprecision continuous polishing.This study provides a comprehensive method for evaluation of material removal uniformity,which is valuable for the realization of high-quality machining for water-soluble crystals.展开更多
As one of the most important terminals in machining, cutting tools have been widely used for components manufacturing in aerospace and other industries. The quality of these components and processing efficiency are cl...As one of the most important terminals in machining, cutting tools have been widely used for components manufacturing in aerospace and other industries. The quality of these components and processing efficiency are closely linked to the performance of cutting tools. Therefore, it is essential and critical to inspect the cutting tools and monitor the condition during the stage of manufacturing and machining. This review aims to discuss and summarize the key problems, methods,and techniques from the perspective of the tool geometric and the physical quantities measurement,including machine vision, physical sensors and data processing. It is worth mentioning that we focus on the topic of precision measurement methods and discuss universal solutions by identifying the common characteristics of the measured quantities. Eventually, the challenges and future trends for the development of in-depth research and practical applications are concluded. The research and application of precise measurement techniques for geometric and physical quantities will better promote the development of intelligent manufacturing.展开更多
SiC_(f)/SiC ceramic matrix composites(SiC_(f)/SiC composites)are difficult to drill small holes due to their heterogeneity,high hardness,and low electrical conductivity.In order to solve the difficulties of poor quali...SiC_(f)/SiC ceramic matrix composites(SiC_(f)/SiC composites)are difficult to drill small holes due to their heterogeneity,high hardness,and low electrical conductivity.In order to solve the difficulties of poor quality and low efficiency when drilling small holes,a novel femtosecond laser rotary drilling(FLRD)technique is proposed.Beam kinematic paths and experimental studies were carried out to analyze the effects of processing parameters on the drilling results in the two-step drilling process.In the through-hole drilling stage,the material removal rate increases with increasing laser power,decreasing feed speed and decreasing pitch.As for the finishing stage of drilling,the exit diameter increased with increasing laser power and decreasing feed speed.The drilling parameters were selected by taking the processing efficiency of through-hole and the quality of finished hole as the constraint criteria.Holes with a diameter of 500μm were drilled using FLRD in 3 mm thick SiC_(f)/SiC composites with a drilling time<150 s.The hole aspect ratio was 6,the taper<0.2°,and there was no significant thermal damage at the orifice or the wall of the hole.The FLRD provides a solution for precision machining of small holes in difficult-to-machine materials by offering the advantages of high processing quality and short drilling times.展开更多
Trochoidal milling is known for its advantages in machining difficult-to-machine materials as it facilitates chip removal and tool cooling.However,the conventional trochoidal tool path presents challenges such as lowe...Trochoidal milling is known for its advantages in machining difficult-to-machine materials as it facilitates chip removal and tool cooling.However,the conventional trochoidal tool path presents challenges such as lower machining efficiency and longer machining time due to its time-varying cutter-workpiece engagement angle and a high percentage of non-cutting tool paths.To address these issues,this paper introduces a parameter-variant trochoidal-like(PVTR)tool path planning method for chatter-free and high-efficiency milling.This method ensures a constant engagement angle for each tool path period by adjusting the trochoidal radius and step.Initially,the nonlinear equation for the PVTR toolpath is established.Then,a segmented recurrence method is proposed to plan tool paths based on the desired engagement angle.The impact of trochoidal tool path parameters on the engagement angle is analyzed and coupled this information with the milling stability model based on spindle speed and engagement angle to determine the desired engagement angle throughout the machining process.Finally,several experimental tests are carried out using the bull-nose end mill to validate the feasibility and effectiveness of the proposed method.展开更多
Due to the high hardness and low fracture toughness of the single crystal silicon(SCS),it is highly susceptible to microscopic cracks and subsurface damage during processing.In this paper,we propose to adjust the mech...Due to the high hardness and low fracture toughness of the single crystal silicon(SCS),it is highly susceptible to microscopic cracks and subsurface damage during processing.In this paper,we propose to adjust the mechanical properties of SCS by cold plasma jet,and systematically investigate the influences of the plasma on material deformation and damage mechanisms by nanoscratch tests.The results indicate that the plasma can increase the critical normal force for the plastic-brittle(P-B)conversion of SCS.Compared with the ordinary nanoscratch test,the critical force for P-B conversion of plasma-assisted scratching at 1μm/s can increase from 43.6 to 66.4 mN.Increasing the scratching speed under ordinary conditions can enhance the plastic deformability of SCS to some extent,but its effect is not as effective as that of plasma;in addition,the increased scratching speed causes the shear bands(SBs)to lack time to propagate,so the quantity of SBs under plasma-assisted scratching at 10μm/s is reduced compared to 1μm/s.From subsurface damage topographies,the highly localized amorphous SBs cause the generation of subsurface cracks.The cold plasma can alleviate cracks on the scratched subsurface of SCS by introducing multiple SBs and stacking faults.This paper may provide a novel strategy for high-efficiency and low-damage ultra-precision machining of hard and brittle materials.展开更多
The double-sided lapping process is extensively employed in the manufacturing of wafers,optical windows,and seal rings due to its high efficiency and ability to achieve precise flatness.However,limited research has ex...The double-sided lapping process is extensively employed in the manufacturing of wafers,optical windows,and seal rings due to its high efficiency and ability to achieve precise flatness.However,limited research has explored the thickness uniformity among different workpieces after double-sided lapping,and the underlying mechanism remains unclear.To address the demand for higher precision,this paper first analyzed the relative kinematic model between the workpiece and the lapping plate to clarify the causes of thickness variations among workpieces after double-sided lapping.Subsequently,a finite element method(FEM)model was developed to account for the pressure distribution on the workpiece surfaces at the initial stage of the process.The results indicate that the number of workpieces influences the final thickness variation.Then,various sets of thin copper plates with different thicknesses were lapped,and the findings revealed that five copper plates processed simultaneously exhibited more uniform thickness compared to the three plates.The experimental results align well with the theoretical analysis.Ultimately,a thickness variation of less than 6μm was achieved on five copper plates measuringΦ100×2.9 mm.This study presents a comprehensive analysis of the mechanisms influencing thickness uniformity in the double-sided lapping process and provides practical guidelines for optimizing the process to achieve stringent precision standards in industrial applications.展开更多
Leveraging surface texturing to realize significant friction reduction at contact interfaces has emerged as a preferred technique among tribology experts,boosting tribological energy efficiency and sustainability.This...Leveraging surface texturing to realize significant friction reduction at contact interfaces has emerged as a preferred technique among tribology experts,boosting tribological energy efficiency and sustainability.This review systematically demonstrates optimization strategies,advanced manufacturing methods,typical applications,and outlooks of technical challenges toward surface texturing for friction reduction.Firstly,the lubricated contact models of microtextures are introduced.Then,we provide a framework of state-of-the-art research on synergistic friction optimization strategies of microtexture structures,surface treatments,liquid lubricants,and external energy fields.A comparative analysis evaluates the strengths and weaknesses of manufacturing techniques commonly employed for microtextured surfaces.The latest research advancements in microtextures in different application scenarios are highlighted.Finally,the challenges and directions of future research on surface texturing technology are briefly addressed.This review aims to elaborate on the worldwide progress in the optimization,manufacturing,and application of microtexture-enabled friction reduction technologies to promote their practical utilizations.展开更多
Modern industrial equipment is increasingly characterized by miniaturization,integration,and high performance,necessitating the production of complex structural parts with exceptionally high internal surface quality.D...Modern industrial equipment is increasingly characterized by miniaturization,integration,and high performance,necessitating the production of complex structural parts with exceptionally high internal surface quality.Direct manufacturing often leads to high internal surface roughness,which traditional finishing and measuring methods cannot adequately address due to the decreasing size and increasing complexity of internal structures.This is especially true for components like pipes with large aspect ratios,extremely small deep holes,multi-stage bends,cross pipes,and array holes.To meet the high-performance manufacturing demands of these parts,advanced internal surface finishing and roughness measurement technologies have gained significant attention.This review focuses on the challenges and solutions related to internal surface parts with various apertures and complex structures.Internal surface finishing methods are categorized into mechanical finishing,fluid-based finishing,and energy-field-based finishing based on their characteristics.Roughness measurement technologies are divided into tool-probing and non-probing methods.The principles,required equipment,and key parameters of each finishing and measurement approach are discussed in detail.Additionally,the advantages and limitations of these methods are summarized,and future trends are forecasted.This paper serves as a comprehensive guide for researchers and engineers aiming to enhance the internal surface quality of complex structure parts.展开更多
Atomic surfaces are strictly required by high-performance devices of diamond.Nevertheless,diamond is the hardest material in nature,leading to the low material removal rate(MRR)and high surface roughness during machin...Atomic surfaces are strictly required by high-performance devices of diamond.Nevertheless,diamond is the hardest material in nature,leading to the low material removal rate(MRR)and high surface roughness during machining.Noxious slurries are widely used in conventional chemical mechanical polishing(CMP),resulting in the possible pollution to the environment.Moreover,the traditional slurries normally contain more than four ingredients,causing difficulties to control the process and quality of CMP.To solve these challenges,a novel green CMP for single crystal diamond was developed,consisting of only hydrogen peroxide,diamond abrasive and Prussian blue(PB)/titania catalyst.After CMP,atomic surface is achieved with surface roughness Sa of 0.079 nm,and the MRR is 1168 nm·h^(-1).Thickness of damaged layer is merely 0.66 nm confirmed by transmission electron microscopy(TEM).X-ray photoelectron spectroscopy,electron paramagnetic resonance and TEM reveal that·OH radicals form under ultraviolet irradiation on PB/titania catalyst.The·OH radicals oxidize diamond,transforming it from monocrystalline to amorphous atomic structure,generating a soft amorphous layer.This contributes the high MRR and formation of atomic surface on diamond.The developed novel green CMP offers new insights to achieve atomic surface of diamond for potential use in their high-performance devices.展开更多
High-performance devices usually have curved surfaces, requiring high accuracy of shape and low surface roughness. It is a challenge to achieve high accuracies for form and position on a device with low surface roughn...High-performance devices usually have curved surfaces, requiring high accuracy of shape and low surface roughness. It is a challenge to achieve high accuracies for form and position on a device with low surface roughness. However, due to the unique nonlinear rheology, magnetorheological fluids with hard abrasives are widely applied in ultra-precision surface finishing. Compared with conventional mechanical finishing, magnetorheological finishing displays obviously advantages, such as high precision shape of machined surface, low surface roughness and subsurface damage, and easy control for finishing processes. However, finishing performance depends on various factors, e.g. volume fraction and distribution of magnetic particles, types of hard abrasives and additives, strength of magnetic field, finishing forms. Therefore, a comprehensive review on related works is essential to understand the state-of-the-art of magnetorheological finishing and beneficial to inspire researchers to develop lower cost, higher machining accuracy and efficient approaches and setups, which demonstrates a significant guidance for development of high-performance parts in fields of aerospace, navigation and clinical medicine etc. This review starts from the rheological property of magnetorheological fluids, summarizing dynamically nonlinear rheological properties and stable finishing approaches. Then, the effect of components in magnetorheological fluids is discussed on finishing performance, consisting of magnetic particles, carrier fluid, additives and abrasives. Reasonable configuration of magnetorheological fluids, and different magnetorheological finishing methods are presented for variously curved surfaces. In addition, the current finishing forms and future directions are also addressed in this review.展开更多
Advanced photovoltaics,such as ultra-flexible perovskite solar cells(UF-PSCs),which are known for their lightweight design and high power-to-mass ratio,have been a long-standing goal that we,as humans,have continuousl...Advanced photovoltaics,such as ultra-flexible perovskite solar cells(UF-PSCs),which are known for their lightweight design and high power-to-mass ratio,have been a long-standing goal that we,as humans,have continuously pursued.Unlike normal PSCs fabricated on rigid substrates,producing high-efficiency UF-PSCs remains a challenge due to the difficulty in achieving full coverage and minimizing defects of metal halide perovskite(MHP)films.In this study,we utilized Al_(2)O_(3) nanoparticles(NPs)as an inorganic surface modifier to enhance the wettability and reduce the roughness of poly-bis(4-phenyl)(2,4,6-trimethylphenyl)amine simultaneously.This approach proves essentials in fabricating UF-PSCs,enabling the deposition of uniform and dense MHP films with full coverage and fewer defects.We systematically investigated the effect of Al_(2)O_(3) NPs on film formation,combining simulation with experiments.Our strategy not only significantly increases the power conversion efficiency(PCE)from 11.96%to 16.33%,but also promotes reproducibility by effectively addressing the short circuit issue commonly encountered in UF-PSCs.Additionally,our UF-PSCs demonstrates good mechanical stability,maintaining 98.6%and 79.0%of their initial PCEs after 10,000 bending cycles with radii of 1.0 and 0.5 mm,respectively.展开更多
Surrogate models offer an efficient approach to tackle the computationally intensive evaluation of performance functions in reliability analysis.Nevertheless,the approximations inherent in surrogate models necessitate...Surrogate models offer an efficient approach to tackle the computationally intensive evaluation of performance functions in reliability analysis.Nevertheless,the approximations inherent in surrogate models necessitate the consideration of surrogate model uncertainty in estimating failure probabilities.This paper proposes a new reliability analysis method in which the uncertainty from the Kriging surrogate model is quantified simultaneously.This method treats surrogate model uncertainty as an independent entity,characterizing the estimation error of failure probabilities.Building upon the probabilistic classification function,a failure probability uncertainty is proposed by integrating the difference between the traditional indicator function and the probabilistic classification function to quantify the impact of surrogate model uncertainty on failure probability estimation.Furthermore,the proposed uncertainty quantification method is applied to a newly designed reliability analysis approach termed SUQ-MCS,incorporating a proposed median approximation function for active learning.The proposed failure probability uncertainty serves as the stopping criterion of this framework.Through benchmarking,the effectiveness of the proposed uncertainty quantification method is validated.The empirical results present the competitive performance of the SUQ-MCS method relative to alternative approaches.展开更多
Fatigue properties are crucial for critical aero-engine components in extreme serviceenvironments,which are significantly affected by surface integrity(SI)indexes(especially surface topography,residual stressσ_(res),...Fatigue properties are crucial for critical aero-engine components in extreme serviceenvironments,which are significantly affected by surface integrity(SI)indexes(especially surface topography,residual stressσ_(res),and microhardness)after machining processes.Normal-direction ultrasonic vibration-assisted face grinding(ND-UVAFG)has advantages in improving the machinability of Inconel 718,but there is a competitive relationship between higher compressiveσ_(res)and higher surface roughness R_(a)in affecting fatigue strength.The lack of a quantitative relationship between multiple SI indexes and fatigue strength makes theindeterminacy of a regulatory strategy for improving fatigue properties.In this work,a model of fatigue strength(σ_f)_(sur)considering multiple SI indexes was developed.Then,high-cycle fatigue tests were carried out on Inconel 718 samples with different SI characteristics,and the influence of ND-UVAFG process parameters on SI was analyzed.Based on SI indexes data,the(σ_f)_(sur)distribution in the grinding surface layer for ND-UVAFG Inconel 718 samples was determined using the developed model,and then the fatigue crack initiation(FCI)sites were furtherpredicted.The predicted FCI sites corresponded well with the experimental results,therebyverifying this model.A strategy for improving the fatigue life was proposed in this work,which was to transfer the fatigue source from the machined surface to the bulk material by controlling the SI indexes.Finally,a critical condition of SI indexes that FCI sites appeared on the surface or in bulk material was given by fitting the predicted results.According to the critical condition,an SI field where FCI sites appeared in the bulk material could be obtained.In this field,thefatigue life of Inconel 718 samples could be improved by approximately 140%.展开更多
It is a challenge to polish the interior surface of an additively manufactured component with complex structures and groove sizes less than 1 mm.Traditional polishing methods are disabled to polish the component,meanw...It is a challenge to polish the interior surface of an additively manufactured component with complex structures and groove sizes less than 1 mm.Traditional polishing methods are disabled to polish the component,meanwhile keeping the structure intact.To overcome this challenge,small-grooved components made of aluminum alloy with sizes less than 1 mm were fabricated by a custom-made printer.A novel approach to multi-phase jet(MPJ)polishing is proposed,utilizing a self-developed polisher that incorporates solid,liquid,and gas phases.In contrast,abrasive air jet(AAJ)polishing is recommended,employing a customized polisher that combines solid and gas phases.After jet polishing,surface roughness(Sa)on the interior surface of grooves decreases from pristine 8.596μm to 0.701μm and 0.336μm via AAJ polishing and MPJ polishing,respectively,and Sa reduces 92%and 96%,correspondingly.Furthermore,a formula defining the relationship between linear energy density and unit defect volume has been developed.The optimized parameters in additive manufacturing are that linear energy density varies from 0.135 J mm^(-1)to 0.22 J mm^(-1).The unit area defect volume achieved via the optimized parameters decreases to 1/12 of that achieved via non-optimized ones.Computational fluid dynamics simulation results reveal that material is removed by shear stress,and the alumina abrasives experience multiple collisions with the defects on the heat pipe groove,resulting in uniform material removal.This is in good agreement with the experimental results.The novel proposed setups,approach,and findings provide new insights into manufacturing complex-structured components,polishing the small-grooved structure,and keeping it unbroken.展开更多
The transistor-inspired Droplet-based Electricity Generator(DEG)significantly enhances the energy collection efficiency from single-position droplets.However,the design of the DEG arrays combining high output performa...The transistor-inspired Droplet-based Electricity Generator(DEG)significantly enhances the energy collection efficiency from single-position droplets.However,the design of the DEG arrays combining high output performance and large-scale integration under multi-position droplet impacts remains a challenge.Inspired by the unique structure of the honeycomb,we developed an Independent-Cell Droplet-based Electricity Generator(IC-DEG)array that allows for high-efficiency and stable droplet energy harvesting under multi-position droplet impacts.Each independent cell is a transistor-inspired Tubular Droplet-based Electricity Generator(T-DEG),which ensures the high electrical output of the IC-DEG array.The honeycomb-like arrangement improves the space utilization,accelerates the detachment of droplets,and avoids electrical interference among independent cells,all of which further enhance the IC-DEG array performance.The average peak open-circuit voltage of the IC-DEG array is 265.2 V,and 96.6%of peak voltages exceed 200 V,almost double that of a traditional planar array.Moreover,the average droplet detachment time of the IC-DEG array is 44.8 ms,41.4%shorter than the traditional planar array.The enhanced performance of the IC-DEG array is further demonstrated by the high speed of charging capacitors and the capability of driving electronic devices.This study provides a promising design concept for large-scale droplet energy harvesting devices.展开更多
Double-sided lapping is an precision machining method capable of obtaining high-precision surface.However,during the lapping process of thin pure copper substrate,the workpiece will be warped due to the influence of r...Double-sided lapping is an precision machining method capable of obtaining high-precision surface.However,during the lapping process of thin pure copper substrate,the workpiece will be warped due to the influence of residual stress,including the machining stress and initial residual stress,which will deteriorate the flatness of the workpiece and ultimately affect the performance of components.In this study,finite element method(FEM)was adopted to study the effect of residual stress-related on the deformation of pure copper substrate during double-sided lapping.Considering the initial residual stress of the workpiece,the stress caused by the lapping and their distribution characteristics,a prediction model was proposed for simulating workpiece machining deformation in lapping process by measuring the material removal rate of the upper and lower surfaces of the workpiece under the corresponding parameters.The results showed that the primary cause of the warping deformation of the workpiece in the doublesided lapping is the redistribution of initial residual stress caused by uneven material removal on the both surfaces.The finite element simulation results were in good agreement with the experimental results.展开更多
Polymer nanowire(NW)organic field-effect transistors(OFETs)integrated on highly aligned large-area flexible substrates are candidate structures for the development of high-performance flexible electronics.This work pr...Polymer nanowire(NW)organic field-effect transistors(OFETs)integrated on highly aligned large-area flexible substrates are candidate structures for the development of high-performance flexible electronics.This work presents a universal technique,coaxial focused electrohydrodynamic jet(CFEJ)printing technology,to fabricate highly aligned 90-nm-diameter polymer arrays.This method allows for the preparation of uniformly shaped and precisely positioned nanowires directly on flexible substrates without transfer,thus ensuring their electrical properties.Using indacenodithiophene-co-benzothiadiazole(IDT-BT)and poly(9,9-dioctylfluorene-co-benzothiadiazole)(F8-BT)as example materials,5 cm^(2) arrays were prepared with only minute size variations,which is extremely difficult to do using previously reported methods.According to 2D-GIXRD analysis,the molecules inside the nanowires mainly adopted face-onπ-stacking crystallite arrangements.This is quite different from the mixed arrangement of thin films.Nanowire-based OFETs exhibited a high average hole mobility of 1.1 cm^(2) V^(−1) s^(−1) and good device uniformity,indicating the applicability of CFEJ printing as a potential batch manufacturing and integration process for high-performance,scalable polymer nanowire-based OFET circuits.This technique can be used to fabricate various polymer arrays,enabling the use of organic polymer semiconductors in large-area,high-performance electronic devices and providing a new path for the fabrication of flexible displays and wearable electronics in the future.展开更多
文摘The increasing demand for high-end equipment in crucial sectors such as aerospace,aeronautics, energy, power, information and electronics continues growing. However, the manufacturing of such advanced equipment poses significant challenges owing to high-level requirements for loading, transmission, conduction, energy conversion, and stealth. These challenges are amplified by complex structures, hard-to-cut materials, and strict standards for surface integrity and precision. To overcome these barriers in high-end equipment manufacturing, high-performance manufacturing(HPM) has emerged as an essential solution.This paper firstly discusses the key challenges in manufacturing technology and explores the essence of HPM, outlining a quantitative relationship between design and manufacturing.Subsequently, a generalized framework of HPM is proposed, accompanied by an in-depth exploration of the foundational elements and criteria. Ultimately, the feasible approaches and enabling technologies, supported by the analysis of two illustrative case studies are demonstrated. It is concluded that HPM is not just a precision and computational manufacturing framework with a core focus on multiparameter correlation in design, manufacturing, and service environments. It also represents a performance-geometry-integrated manufacturing framework for an accurate guarantee of the optimal performance.
基金supported by the National Key Research and Development Program of China(2022YFB3605902)the National Natural Science Foundation of China(52375411,52293402)。
文摘Workpiece rotational grinding is widely used in the ultra-precision machining of hard and brittle semiconductor materials,including single-crystal silicon,silicon carbide,and gallium arsenide.Surface roughness and subsurface damage depth(SDD)are crucial indicators for evaluating the surface quality of these materials after grinding.Existing prediction models lack general applicability and do not accurately account for the complex material behavior under grinding conditions.This paper introduces novel models for predicting both surface roughness and SDD in hard and brittle semiconductor materials.The surface roughness model uniquely incorporates the material’s elastic recovery properties,revealing the significant impact of these properties on prediction accuracy.The SDD model is distinguished by its analysis of the interactions between abrasive grits and the workpiece,as well as the mechanisms governing stress-induced damage evolution.The surface roughness model and SDD model both establish a stable relationship with the grit depth of cut(GDC).Additionally,we have developed an analytical relationship between the GDC and grinding process parameters.This,in turn,enables the establishment of an analytical framework for predicting surface roughness and SDD based on grinding process parameters,which cannot be achieved by previous models.The models were validated through systematic experiments on three different semiconductor materials,demonstrating excellent agreement with experimental data,with prediction errors of 6.3%for surface roughness and6.9%for SDD.Additionally,this study identifies variations in elastic recovery and material plasticity as critical factors influencing surface roughness and SDD across different materials.These findings significantly advance the accuracy of predictive models and broaden their applicability for grinding hard and brittle semiconductor materials.
基金support from the National Natural Science Foundation of China(No.52175291)the Natural Science Foundation of Liaoning Province(No.2022-YGJC-22).
文摘Recently,rapid and cost-effective additive manufacturing solutions for lightweight aluminum alloys with excellent high-temperature mechanical properties have been increasingly in demand.In this study,we combined laser-arc hybrid additive manufacturing with solution and artificial aging treatments to achieve Al-Zn-Mg-Cu alloy with favorable high-temperature strength via microstructure control.Hydrogen pores became the major defect in the as-deposited and heat-treated specimens.The continuous distribution of eutectics with hard-brittle characteristics at the grain boundaries was destructed following heat treat-ment.High-densityηprecipitates were uniformly dispersed in the heat-treated Al-Zn-Mg-Cu alloy,whereas appeared coarsened and dissolved at 473 K,owing to the rapid diffusion of Zn and Mg.The average 0.2%yield strength(318±16 MPa)and ultimate tensile strength(362±20 MPa)at 473 K af-ter heat treatment were enhanced by approximately 58%and 51%,respectively,compared to those of the as-deposited specimen.In addition,theηprecipitates contributed to lattice distortions and strain fields,which prevented dislocation motion and increased slip deformation resistance at high temper-atures.The as-deposited specimen exhibited intergranular fracture at 473 K,with cracks preferring to propagate along the aggregated eutectics.However,crack propagation proceeded in the sections with more pores in the heat-treated specimen.Our approach may provide a valid option for achieving alu-minum alloys with excellent high-temperature mechanical properties.
基金Supported by National Key Research and Development Program of China(Grant No.2023YFB4603602)High-Quality Development Project(Grant No.TC220H05S-007)。
文摘Water dissolution ultraprecision continuous polishing is a nontraditional machining method specifically designed for water-soluble crystals.The aim of this study is primarily to reduce the surface roughness for small sizes from an experimental standpoint.A trajectory uniformity simulation analysis is carried out for a consistent material removal.A material removal model is developed based on the water dissolution principle and kinematic analysis.Numerical simulations of single-and multiple-water-core polishing trajectories are performed to explore the influences of the processing parameters such as movement form,number of water cores,speed ratio,polishing time,and period ratio on the material removal uniformity.The material removal rate is calculated according to the Preston equation.The trajectory density nonuniformity is utilized to evaluate the global uniformity of the trajectory distributions and optimize the processing parameters for a better material removal uniformity.Verification experiments are conducted on a large-size ultraprecision continuous polisher using a typical potassium dihydrogen phosphate(KDP)crystal with a water-soluble structure.The edge collapse is improved from 51.499μm to 1.477μm by trajectory uniformity optimization.The changing trends of line profile variations in the validation experiment and simulation are similar.An ultrasmooth surface of a 180 mm×180 mm KDP crystal with a surface roughness root mean square of 1.718 nm is obtained after water dissolution ultraprecision continuous polishing.This study provides a comprehensive method for evaluation of material removal uniformity,which is valuable for the realization of high-quality machining for water-soluble crystals.
基金co-supported by the National Key Research and Development Project of China (No. 2018YFA0703304)the National Natural Science Foundation of China (Nos. 52125504, 92148301, 52090053)。
文摘As one of the most important terminals in machining, cutting tools have been widely used for components manufacturing in aerospace and other industries. The quality of these components and processing efficiency are closely linked to the performance of cutting tools. Therefore, it is essential and critical to inspect the cutting tools and monitor the condition during the stage of manufacturing and machining. This review aims to discuss and summarize the key problems, methods,and techniques from the perspective of the tool geometric and the physical quantities measurement,including machine vision, physical sensors and data processing. It is worth mentioning that we focus on the topic of precision measurement methods and discuss universal solutions by identifying the common characteristics of the measured quantities. Eventually, the challenges and future trends for the development of in-depth research and practical applications are concluded. The research and application of precise measurement techniques for geometric and physical quantities will better promote the development of intelligent manufacturing.
基金the support of the Xingliao Talent Program of Liaoning Province(No.XLYC2001004)the High Level Talents Innovation Plan of Dalian(No.2020RD02)the Fundamental Research Funds for the Central Universities(No.DUT22LAB501).
文摘SiC_(f)/SiC ceramic matrix composites(SiC_(f)/SiC composites)are difficult to drill small holes due to their heterogeneity,high hardness,and low electrical conductivity.In order to solve the difficulties of poor quality and low efficiency when drilling small holes,a novel femtosecond laser rotary drilling(FLRD)technique is proposed.Beam kinematic paths and experimental studies were carried out to analyze the effects of processing parameters on the drilling results in the two-step drilling process.In the through-hole drilling stage,the material removal rate increases with increasing laser power,decreasing feed speed and decreasing pitch.As for the finishing stage of drilling,the exit diameter increased with increasing laser power and decreasing feed speed.The drilling parameters were selected by taking the processing efficiency of through-hole and the quality of finished hole as the constraint criteria.Holes with a diameter of 500μm were drilled using FLRD in 3 mm thick SiC_(f)/SiC composites with a drilling time<150 s.The hole aspect ratio was 6,the taper<0.2°,and there was no significant thermal damage at the orifice or the wall of the hole.The FLRD provides a solution for precision machining of small holes in difficult-to-machine materials by offering the advantages of high processing quality and short drilling times.
基金supported by the National Natural Science Foundation of China(Grant Nos.U22A20202 and 52275477).
文摘Trochoidal milling is known for its advantages in machining difficult-to-machine materials as it facilitates chip removal and tool cooling.However,the conventional trochoidal tool path presents challenges such as lower machining efficiency and longer machining time due to its time-varying cutter-workpiece engagement angle and a high percentage of non-cutting tool paths.To address these issues,this paper introduces a parameter-variant trochoidal-like(PVTR)tool path planning method for chatter-free and high-efficiency milling.This method ensures a constant engagement angle for each tool path period by adjusting the trochoidal radius and step.Initially,the nonlinear equation for the PVTR toolpath is established.Then,a segmented recurrence method is proposed to plan tool paths based on the desired engagement angle.The impact of trochoidal tool path parameters on the engagement angle is analyzed and coupled this information with the milling stability model based on spindle speed and engagement angle to determine the desired engagement angle throughout the machining process.Finally,several experimental tests are carried out using the bull-nose end mill to validate the feasibility and effectiveness of the proposed method.
基金Supported by National Natural Science Foundation of China(Grant No.52475430)the Fundamental Research Funds for the Central Universities(Grant No.DUT23YG118).
文摘Due to the high hardness and low fracture toughness of the single crystal silicon(SCS),it is highly susceptible to microscopic cracks and subsurface damage during processing.In this paper,we propose to adjust the mechanical properties of SCS by cold plasma jet,and systematically investigate the influences of the plasma on material deformation and damage mechanisms by nanoscratch tests.The results indicate that the plasma can increase the critical normal force for the plastic-brittle(P-B)conversion of SCS.Compared with the ordinary nanoscratch test,the critical force for P-B conversion of plasma-assisted scratching at 1μm/s can increase from 43.6 to 66.4 mN.Increasing the scratching speed under ordinary conditions can enhance the plastic deformability of SCS to some extent,but its effect is not as effective as that of plasma;in addition,the increased scratching speed causes the shear bands(SBs)to lack time to propagate,so the quantity of SBs under plasma-assisted scratching at 10μm/s is reduced compared to 1μm/s.From subsurface damage topographies,the highly localized amorphous SBs cause the generation of subsurface cracks.The cold plasma can alleviate cracks on the scratched subsurface of SCS by introducing multiple SBs and stacking faults.This paper may provide a novel strategy for high-efficiency and low-damage ultra-precision machining of hard and brittle materials.
基金Supported by the Liaoning Provincial Natural Science Foundation(Grant No.2023-MSBA-008)Unveiling and Commanding Program of Liaoning Province(Grant No.2022JH1/10800080)the Fundamental Research Funds for the Central Universities(Grant No.DUT24MS008).
文摘The double-sided lapping process is extensively employed in the manufacturing of wafers,optical windows,and seal rings due to its high efficiency and ability to achieve precise flatness.However,limited research has explored the thickness uniformity among different workpieces after double-sided lapping,and the underlying mechanism remains unclear.To address the demand for higher precision,this paper first analyzed the relative kinematic model between the workpiece and the lapping plate to clarify the causes of thickness variations among workpieces after double-sided lapping.Subsequently,a finite element method(FEM)model was developed to account for the pressure distribution on the workpiece surfaces at the initial stage of the process.The results indicate that the number of workpieces influences the final thickness variation.Then,various sets of thin copper plates with different thicknesses were lapped,and the findings revealed that five copper plates processed simultaneously exhibited more uniform thickness compared to the three plates.The experimental results align well with the theoretical analysis.Ultimately,a thickness variation of less than 6μm was achieved on five copper plates measuringΦ100×2.9 mm.This study presents a comprehensive analysis of the mechanisms influencing thickness uniformity in the double-sided lapping process and provides practical guidelines for optimizing the process to achieve stringent precision standards in industrial applications.
基金the National Natural Science Foundation of China(Award No.07120016)support by the Dalian University of Technology(DUT)(Award Nos.82232022,82232043,and DUT22LAB404)AVIC Shenyang Aircraft Company(Award No.12020641 and 12020642)。
文摘Leveraging surface texturing to realize significant friction reduction at contact interfaces has emerged as a preferred technique among tribology experts,boosting tribological energy efficiency and sustainability.This review systematically demonstrates optimization strategies,advanced manufacturing methods,typical applications,and outlooks of technical challenges toward surface texturing for friction reduction.Firstly,the lubricated contact models of microtextures are introduced.Then,we provide a framework of state-of-the-art research on synergistic friction optimization strategies of microtexture structures,surface treatments,liquid lubricants,and external energy fields.A comparative analysis evaluates the strengths and weaknesses of manufacturing techniques commonly employed for microtextured surfaces.The latest research advancements in microtextures in different application scenarios are highlighted.Finally,the challenges and directions of future research on surface texturing technology are briefly addressed.This review aims to elaborate on the worldwide progress in the optimization,manufacturing,and application of microtexture-enabled friction reduction technologies to promote their practical utilizations.
基金the financial supports from National Key R&D Program of China(No.2022YFB3403301)the Funds for International Cooperation and Exchange of the National Natural Science Foundation of China(No.52311530080)。
文摘Modern industrial equipment is increasingly characterized by miniaturization,integration,and high performance,necessitating the production of complex structural parts with exceptionally high internal surface quality.Direct manufacturing often leads to high internal surface roughness,which traditional finishing and measuring methods cannot adequately address due to the decreasing size and increasing complexity of internal structures.This is especially true for components like pipes with large aspect ratios,extremely small deep holes,multi-stage bends,cross pipes,and array holes.To meet the high-performance manufacturing demands of these parts,advanced internal surface finishing and roughness measurement technologies have gained significant attention.This review focuses on the challenges and solutions related to internal surface parts with various apertures and complex structures.Internal surface finishing methods are categorized into mechanical finishing,fluid-based finishing,and energy-field-based finishing based on their characteristics.Roughness measurement technologies are divided into tool-probing and non-probing methods.The principles,required equipment,and key parameters of each finishing and measurement approach are discussed in detail.Additionally,the advantages and limitations of these methods are summarized,and future trends are forecasted.This paper serves as a comprehensive guide for researchers and engineers aiming to enhance the internal surface quality of complex structure parts.
基金financial support from the National Key Research and Development Program of China(2018YFA0703400)the Fundamental Research Funds for the Provincial Universities of Zhejiang(GK239909299001021)+1 种基金the Ninth China Association for Science and Technology Youth Talent Lift Project Support Plan(KYZ015324002)the Changjiang Scholars Program of Chinese Ministry of Education。
文摘Atomic surfaces are strictly required by high-performance devices of diamond.Nevertheless,diamond is the hardest material in nature,leading to the low material removal rate(MRR)and high surface roughness during machining.Noxious slurries are widely used in conventional chemical mechanical polishing(CMP),resulting in the possible pollution to the environment.Moreover,the traditional slurries normally contain more than four ingredients,causing difficulties to control the process and quality of CMP.To solve these challenges,a novel green CMP for single crystal diamond was developed,consisting of only hydrogen peroxide,diamond abrasive and Prussian blue(PB)/titania catalyst.After CMP,atomic surface is achieved with surface roughness Sa of 0.079 nm,and the MRR is 1168 nm·h^(-1).Thickness of damaged layer is merely 0.66 nm confirmed by transmission electron microscopy(TEM).X-ray photoelectron spectroscopy,electron paramagnetic resonance and TEM reveal that·OH radicals form under ultraviolet irradiation on PB/titania catalyst.The·OH radicals oxidize diamond,transforming it from monocrystalline to amorphous atomic structure,generating a soft amorphous layer.This contributes the high MRR and formation of atomic surface on diamond.The developed novel green CMP offers new insights to achieve atomic surface of diamond for potential use in their high-performance devices.
基金funded by the National Key Research and Development Program of China (2018YFA0703400)the Young Scientists Fund of the National Natural Science Foundation of China (52205447)+2 种基金Changjiang Scholars Program of Chinese Ministry of Educationthe Xinghai Science Funds for Distinguished Young Scholars at Dalian University of Technologythe Collaborative Innovation Center of Major Machine Manufacturing in Liaoning。
文摘High-performance devices usually have curved surfaces, requiring high accuracy of shape and low surface roughness. It is a challenge to achieve high accuracies for form and position on a device with low surface roughness. However, due to the unique nonlinear rheology, magnetorheological fluids with hard abrasives are widely applied in ultra-precision surface finishing. Compared with conventional mechanical finishing, magnetorheological finishing displays obviously advantages, such as high precision shape of machined surface, low surface roughness and subsurface damage, and easy control for finishing processes. However, finishing performance depends on various factors, e.g. volume fraction and distribution of magnetic particles, types of hard abrasives and additives, strength of magnetic field, finishing forms. Therefore, a comprehensive review on related works is essential to understand the state-of-the-art of magnetorheological finishing and beneficial to inspire researchers to develop lower cost, higher machining accuracy and efficient approaches and setups, which demonstrates a significant guidance for development of high-performance parts in fields of aerospace, navigation and clinical medicine etc. This review starts from the rheological property of magnetorheological fluids, summarizing dynamically nonlinear rheological properties and stable finishing approaches. Then, the effect of components in magnetorheological fluids is discussed on finishing performance, consisting of magnetic particles, carrier fluid, additives and abrasives. Reasonable configuration of magnetorheological fluids, and different magnetorheological finishing methods are presented for variously curved surfaces. In addition, the current finishing forms and future directions are also addressed in this review.
基金supported by the National Natural Science Foundation of China(22005043,52272193)the National Key Research and Development Program of China(2019YFA0709102 and 2020YFA0714502)+1 种基金the Liaoning Revitalization Talents Program(XLYC2007038,XLYC2008032)the Fundamental Research Funds for the Central Universities(DUT22LAB602,DUT22GJ201).
文摘Advanced photovoltaics,such as ultra-flexible perovskite solar cells(UF-PSCs),which are known for their lightweight design and high power-to-mass ratio,have been a long-standing goal that we,as humans,have continuously pursued.Unlike normal PSCs fabricated on rigid substrates,producing high-efficiency UF-PSCs remains a challenge due to the difficulty in achieving full coverage and minimizing defects of metal halide perovskite(MHP)films.In this study,we utilized Al_(2)O_(3) nanoparticles(NPs)as an inorganic surface modifier to enhance the wettability and reduce the roughness of poly-bis(4-phenyl)(2,4,6-trimethylphenyl)amine simultaneously.This approach proves essentials in fabricating UF-PSCs,enabling the deposition of uniform and dense MHP films with full coverage and fewer defects.We systematically investigated the effect of Al_(2)O_(3) NPs on film formation,combining simulation with experiments.Our strategy not only significantly increases the power conversion efficiency(PCE)from 11.96%to 16.33%,but also promotes reproducibility by effectively addressing the short circuit issue commonly encountered in UF-PSCs.Additionally,our UF-PSCs demonstrates good mechanical stability,maintaining 98.6%and 79.0%of their initial PCEs after 10,000 bending cycles with radii of 1.0 and 0.5 mm,respectively.
基金supported by the National Key Research and Development Program of China(No.2023YFB3406900)the National Natural Science Foundation of China(No.52075068).
文摘Surrogate models offer an efficient approach to tackle the computationally intensive evaluation of performance functions in reliability analysis.Nevertheless,the approximations inherent in surrogate models necessitate the consideration of surrogate model uncertainty in estimating failure probabilities.This paper proposes a new reliability analysis method in which the uncertainty from the Kriging surrogate model is quantified simultaneously.This method treats surrogate model uncertainty as an independent entity,characterizing the estimation error of failure probabilities.Building upon the probabilistic classification function,a failure probability uncertainty is proposed by integrating the difference between the traditional indicator function and the probabilistic classification function to quantify the impact of surrogate model uncertainty on failure probability estimation.Furthermore,the proposed uncertainty quantification method is applied to a newly designed reliability analysis approach termed SUQ-MCS,incorporating a proposed median approximation function for active learning.The proposed failure probability uncertainty serves as the stopping criterion of this framework.Through benchmarking,the effectiveness of the proposed uncertainty quantification method is validated.The empirical results present the competitive performance of the SUQ-MCS method relative to alternative approaches.
基金support from the National Science Fund of China(52325506)the National Science and Technology Major Project(2017-VII-0002-0095)Fundamental Research Funds for the Central Universities(DUT22LAB501)。
文摘Fatigue properties are crucial for critical aero-engine components in extreme serviceenvironments,which are significantly affected by surface integrity(SI)indexes(especially surface topography,residual stressσ_(res),and microhardness)after machining processes.Normal-direction ultrasonic vibration-assisted face grinding(ND-UVAFG)has advantages in improving the machinability of Inconel 718,but there is a competitive relationship between higher compressiveσ_(res)and higher surface roughness R_(a)in affecting fatigue strength.The lack of a quantitative relationship between multiple SI indexes and fatigue strength makes theindeterminacy of a regulatory strategy for improving fatigue properties.In this work,a model of fatigue strength(σ_f)_(sur)considering multiple SI indexes was developed.Then,high-cycle fatigue tests were carried out on Inconel 718 samples with different SI characteristics,and the influence of ND-UVAFG process parameters on SI was analyzed.Based on SI indexes data,the(σ_f)_(sur)distribution in the grinding surface layer for ND-UVAFG Inconel 718 samples was determined using the developed model,and then the fatigue crack initiation(FCI)sites were furtherpredicted.The predicted FCI sites corresponded well with the experimental results,therebyverifying this model.A strategy for improving the fatigue life was proposed in this work,which was to transfer the fatigue source from the machined surface to the bulk material by controlling the SI indexes.Finally,a critical condition of SI indexes that FCI sites appeared on the surface or in bulk material was given by fitting the predicted results.According to the critical condition,an SI field where FCI sites appeared in the bulk material could be obtained.In this field,thefatigue life of Inconel 718 samples could be improved by approximately 140%.
基金the National Key Research and Development Program of China(2018YFA0703400)the Young Scientists Fund of the National Natural Science Foundation of China(52205447)Changjiang Scholars Program of the Chinese Ministry of Education。
文摘It is a challenge to polish the interior surface of an additively manufactured component with complex structures and groove sizes less than 1 mm.Traditional polishing methods are disabled to polish the component,meanwhile keeping the structure intact.To overcome this challenge,small-grooved components made of aluminum alloy with sizes less than 1 mm were fabricated by a custom-made printer.A novel approach to multi-phase jet(MPJ)polishing is proposed,utilizing a self-developed polisher that incorporates solid,liquid,and gas phases.In contrast,abrasive air jet(AAJ)polishing is recommended,employing a customized polisher that combines solid and gas phases.After jet polishing,surface roughness(Sa)on the interior surface of grooves decreases from pristine 8.596μm to 0.701μm and 0.336μm via AAJ polishing and MPJ polishing,respectively,and Sa reduces 92%and 96%,correspondingly.Furthermore,a formula defining the relationship between linear energy density and unit defect volume has been developed.The optimized parameters in additive manufacturing are that linear energy density varies from 0.135 J mm^(-1)to 0.22 J mm^(-1).The unit area defect volume achieved via the optimized parameters decreases to 1/12 of that achieved via non-optimized ones.Computational fluid dynamics simulation results reveal that material is removed by shear stress,and the alumina abrasives experience multiple collisions with the defects on the heat pipe groove,resulting in uniform material removal.This is in good agreement with the experimental results.The novel proposed setups,approach,and findings provide new insights into manufacturing complex-structured components,polishing the small-grooved structure,and keeping it unbroken.
基金supported by the National Key R&D Program of China(2022YFB4602401)the National Natural Science Foundation of China(52075071).
文摘The transistor-inspired Droplet-based Electricity Generator(DEG)significantly enhances the energy collection efficiency from single-position droplets.However,the design of the DEG arrays combining high output performance and large-scale integration under multi-position droplet impacts remains a challenge.Inspired by the unique structure of the honeycomb,we developed an Independent-Cell Droplet-based Electricity Generator(IC-DEG)array that allows for high-efficiency and stable droplet energy harvesting under multi-position droplet impacts.Each independent cell is a transistor-inspired Tubular Droplet-based Electricity Generator(T-DEG),which ensures the high electrical output of the IC-DEG array.The honeycomb-like arrangement improves the space utilization,accelerates the detachment of droplets,and avoids electrical interference among independent cells,all of which further enhance the IC-DEG array performance.The average peak open-circuit voltage of the IC-DEG array is 265.2 V,and 96.6%of peak voltages exceed 200 V,almost double that of a traditional planar array.Moreover,the average droplet detachment time of the IC-DEG array is 44.8 ms,41.4%shorter than the traditional planar array.The enhanced performance of the IC-DEG array is further demonstrated by the high speed of charging capacitors and the capability of driving electronic devices.This study provides a promising design concept for large-scale droplet energy harvesting devices.
基金National Key Research and Development Program of China(Grant No.2018YFA0702900)Science Challenge Project of China(Grant No.TZ2016006)National Natural Science Foundation of China(Grant No.51975096)。
文摘Double-sided lapping is an precision machining method capable of obtaining high-precision surface.However,during the lapping process of thin pure copper substrate,the workpiece will be warped due to the influence of residual stress,including the machining stress and initial residual stress,which will deteriorate the flatness of the workpiece and ultimately affect the performance of components.In this study,finite element method(FEM)was adopted to study the effect of residual stress-related on the deformation of pure copper substrate during double-sided lapping.Considering the initial residual stress of the workpiece,the stress caused by the lapping and their distribution characteristics,a prediction model was proposed for simulating workpiece machining deformation in lapping process by measuring the material removal rate of the upper and lower surfaces of the workpiece under the corresponding parameters.The results showed that the primary cause of the warping deformation of the workpiece in the doublesided lapping is the redistribution of initial residual stress caused by uneven material removal on the both surfaces.The finite element simulation results were in good agreement with the experimental results.
基金This research was supported by the National Key R&D Program of China(Grant No.2018YFA0703200,D.W.)National Natural Science Foundation of China(51975104 and 62074138,D.W.52003274,Z.Z.)+2 种基金the Fundamental Research Funds for the Central Universities(DUT22LAB405,DUT22QN227)Defense Industrial Technology Development Program(JCKY2020204B004)Ningbo Institute of Dalian University of Technology.The 2D-GIXRD data were obtained at 1W1A,Beijing Synchrotron Radiation Facility.The authors gratefully acknowledge the assistance of researchers of the Diffuse X-ray Scattering Station during the experiments.Special thanks are due to Dr.Cai Rui in the Instrumental Analysis Center of Dalian University of Technology for assistance with AFM analysis.
文摘Polymer nanowire(NW)organic field-effect transistors(OFETs)integrated on highly aligned large-area flexible substrates are candidate structures for the development of high-performance flexible electronics.This work presents a universal technique,coaxial focused electrohydrodynamic jet(CFEJ)printing technology,to fabricate highly aligned 90-nm-diameter polymer arrays.This method allows for the preparation of uniformly shaped and precisely positioned nanowires directly on flexible substrates without transfer,thus ensuring their electrical properties.Using indacenodithiophene-co-benzothiadiazole(IDT-BT)and poly(9,9-dioctylfluorene-co-benzothiadiazole)(F8-BT)as example materials,5 cm^(2) arrays were prepared with only minute size variations,which is extremely difficult to do using previously reported methods.According to 2D-GIXRD analysis,the molecules inside the nanowires mainly adopted face-onπ-stacking crystallite arrangements.This is quite different from the mixed arrangement of thin films.Nanowire-based OFETs exhibited a high average hole mobility of 1.1 cm^(2) V^(−1) s^(−1) and good device uniformity,indicating the applicability of CFEJ printing as a potential batch manufacturing and integration process for high-performance,scalable polymer nanowire-based OFET circuits.This technique can be used to fabricate various polymer arrays,enabling the use of organic polymer semiconductors in large-area,high-performance electronic devices and providing a new path for the fabrication of flexible displays and wearable electronics in the future.
