Long-period fiber gratings have the advantages of small size,corrosion resistance,anti-electro-magnetic interference,and high sensitivity,making them widely used in biomedicine,the power industry,and aerospace.This pa...Long-period fiber gratings have the advantages of small size,corrosion resistance,anti-electro-magnetic interference,and high sensitivity,making them widely used in biomedicine,the power industry,and aerospace.This paper develops a long-period fiber grating sensor based on periodic microchannels.First,a series of linear structures were etched in the cladding of a single-mode fiber by femtosecond laser microma-chining.Then,the laser-modified region was selectively eroded by selective chemical etching to obtain the periodic microchannel structure.Finally,the channels were filled with polydimethylsiloxane(PDMS)to im-prove the spectral quality.The experimental results show that the sensor has good sensitivity in the measure-ment of various parameters such as temperature,stress,refractive index(RI),and bending.It has a temperat-ure sensitivity of−55.19 pm/℃,a strain sensitivity of−3.19 pm/με,a maximum refractive index sensitivity of 540.28 nm/RIU,and a bending sensitivity of 2.65 dB/m^(-1).All of the measurement parameters show good lin-ear responses.The sensor has strong application prospects in the field of precision measurement and sensing.展开更多
While laser surface texturing(LST)is a promising manufacturing technique for surface functionalization,simultaneously realizing high precision and high efficiency in the LST of complex curved surface is challenging,du...While laser surface texturing(LST)is a promising manufacturing technique for surface functionalization,simultaneously realizing high precision and high efficiency in the LST of complex curved surface is challenging,due to continuously varied geometries of laser-matter incidence.In the present work,we propose a novel manufacturing system of 7-axis on-the-fly LST for complex curved surface,based on the integrated synchronization of 5-axis linkage motion platform with 2-axis galvanometer.Specifically,the algorithm for decomposing spatial texture trajectory on curved surface into low-frequency and high-frequency parts is established,based on which the kinematic model of synchronized 7-axis system is developed to derive the motion of each axis in both 5-axis linkage motion platform and 2-axis galvanometer simultaneously.Subsequently,the synchronized 7-axis LST system is experimentally realized,including the setup of mechanical stages integrated with optical path,the configuration of numerical control unit,and the development of processing software.Finally,case study of 7-axis on-the-fly LST of freeform aluminum surface is performed,and the advantages in terms of processing efficiency and texturing accuracy over 5-axis linkage LST are demonstrated.The correlation of reduced following errors between mechanical stages with the promoted performance of curved surface texturing by the 7-axis on-the-fly LST is further analyzed.Current work provides a feasible solution for establishing the manufacturing system for high performance LST of complex curved surface.展开更多
To mill fine and well-defined micro-dimpled structures,a machining manner of spiral trajectory tool reciprocating motion,where the tool repeats the process of‘feed milling–retract–cutting feed–feed milling again’...To mill fine and well-defined micro-dimpled structures,a machining manner of spiral trajectory tool reciprocating motion,where the tool repeats the process of‘feed milling–retract–cutting feed–feed milling again’along the spiral trajectory,was proposed.From the kinematics analysis,it is found that the machining quality of micro-dimpled structures is highly dependent on the machining trajectory using spiral trajectory tool reciprocating motion.To reveal this causation,simulation modelling and experimental studies were carried out.A simulation model was developed to quantitatively and qualitatively investigate the influence of the trajectory discretization strategies(constant-angle and constant-arc length)and parameters(discrete angle,discrete arc length,and pitch)on surface texture and residual height of micro-dimpled structures.Subsequently,micro-dimpled structures were milled under different trajectory discretization strategies and parameters with spiral trajectory tool reciprocating motion.A comprehensive comparison between the milled results and simulation analysis was made based on geometry accuracy,surface morphology and surface roughness of milled dimples.Meanwhile,the errors and factors affecting the above three aspects were analyzed.The results demonstrate both the feasibility of the established simulation model and the machining capability of this machining way in milling high-quality micro-dimpled structures.Spiral trajectory tool reciprocating motion provides a new machining way for milling micro-dimpled structures and micro-dimpled functional surfaces.And an appropriate machining trajectory can be generated based on the optimized trajectory parameters,thus contributing to the improvement of machining quality and efficiency.展开更多
Thin-walled metal parts with functional micro-featured surface have broad application prospects in the fields of resistance reduction,noise reduction,etc.In this study,a novel micro-rolling&incremental sheet formi...Thin-walled metal parts with functional micro-featured surface have broad application prospects in the fields of resistance reduction,noise reduction,etc.In this study,a novel micro-rolling&incremental sheet forming hybrid process(μR-ISF)is proposed to fabricate thin-walled metal parts with microgroove arrays.An analytical model which relates the rolling force and microgroove depth in the micro-rolling stage was first established.Then,the formation mechanism of microgroove morphology during both micro-rolling stage and macro-shape forming stage are investigated.After the micro-grooved sheet being incrementally formed,a significant reduction(between 21%to nearly 60%)is occurred in the depth of both transverse and longitudinal grooves compared to the flat sheet.Meanwhile,the width of transverse grooves decreases slightly by about 10%on average,while the width of longitudinal microgrooves increases significantly by more than 30%on average.After micro-rolling,85°{102}tensile twins appear on the micro-grooved sheet and the percentage of 65°{112}compressive twins increases.After incremental forming,the percentage of low-angle grain boundaries and the density of geometrically necessary dislocations in the formed part increase significantly,and the grain size distribution becomes more uniform.The present work provides a new strategy for the fabrication of 3D metal thin-walled components with surface micro-features.展开更多
This study presents a comprehensive optimization and comparative analysis of thermoelectric(TE)infrared(IR)detec-tors using Bi_(2)Te_(3) and Si materials.Through theoretical modeling and numerical simulations,we explo...This study presents a comprehensive optimization and comparative analysis of thermoelectric(TE)infrared(IR)detec-tors using Bi_(2)Te_(3) and Si materials.Through theoretical modeling and numerical simulations,we explored the impact of TE mate-rial properties,device structure,and operating conditions on responsivity,detectivity,noise equivalent temperature difference(NETD),and noise equivalent power(NEP).Our study offers an optimally designed IR detector with responsivity and detectivity approaching 2×10^(5) V/W and 6×10^(9) cm∙Hz^(1/2)/W,respectively.This enhancement is attributed to unique design features,includ-ing raised thermal collectors and long suspended thin thermoelectric wire sensing elements embedded in low thermal conductivity organic materials like parylene.Moreover,we demonstrate the compatibility of Bi_(2)Te_(3)-based detector fabrication pro-cesses with existing MEMS foundry processes,facilitating scalability and manufacturability.Importantly,for TE IR detectors,zT/κemerges as a critical parameter contrary to conventional TE material selection based solely on zT(where zT is the thermoelec-tric figure of merit andκis the thermal conductivity).展开更多
Gravimetric resonant-inspired biosensors have attracted increasing attention in industrial and point-ofcare applications,enabling label-free detection of biomarkers such as DNA and antibodies.Capacitive micromachined ...Gravimetric resonant-inspired biosensors have attracted increasing attention in industrial and point-ofcare applications,enabling label-free detection of biomarkers such as DNA and antibodies.Capacitive micromachined ultrasonic transducers(CMUTs)are promising tools for developing miniaturized highperformance biosensing complementary metal–oxide–silicon(CMOS)platforms.However,their operability is limited by inefficient functionalization,aggregation,crosstalk in the buffer,and the requirement for an external high-voltage(HV)power supply.In this study,we aimed to propose a CMUTs-based resonant biosensor integrated with a CMOS front–end interface coupled with ethylene–glycol alkanethiols to detect single-stranded DNA oligonucleotides with large specificity.The topography of the functionalized surface was characterized by energy-dispersive X-ray microanalysis.Improved selectivity for onchip hybridization was demonstrated by comparing complementary and non-complementary singlestranded DNA oligonucleotides using fluorescence imaging technology.The sensor array was further characterized using a five-element lumped equivalent model.The 4 mm^(2) application-specific integrated circuit chip was designed and developed through 0.18 lm HV bipolar-CMOS-double diffused metal–oxide–silicon(DMOS)technology(BCD)to generate on-chip 20 V HV boosting and to track feedback frequency under a standard 1.8 V supply,with a total power consumption of 3.8 mW in a continuous mode.The measured results indicated a detection sensitivity of 7.943×10^(-3) lmol·L^(-1)·Hz^(-1) over a concentration range of 1 to 100 lmol·L^(-1).In conclusion,the label-free biosensing of DNA under dry conditions was successfully demonstrated using a microfabricated CMUT array with a 2 MHz frequency on CMOS electronics with an internal HV supplier.Moreover,ethylene–glycol alkanethiols successfully deposited self-assembled monolayers on aluminum electrodes,which has never been attempted thus far on CMUTs,to enhance the selectivity of bio-functionalization.The findings of this study indicate the possibility of full-on-chip DNA biosensing with CMUTs.展开更多
Electrochemical micromachining （EMM） technology for fabricating micro structures is presented in this article. By applying ultra short pulses, dissolution of a workpiece can be restricted to the region very close to...Electrochemical micromachining （EMM） technology for fabricating micro structures is presented in this article. By applying ultra short pulses, dissolution of a workpiece can be restricted to the region very close to the electrode. First, an EMM system for meeting the requirements of the EMM process is established. Second, sets of experiments is carried out to investigate the influence of some of the predominant electrochemical process parameters such as electrical parameters, feed rate, electrode geometry features and electrolyte composition on machining quality, especially the influences of pulse on time on shape precision and working end shape of electrode on machined surface quality. Finally, after the preliminary experiments, a complex microstructure with good shape precision and surface quality is successfully obtained.展开更多
By using LPCVD SiO 2 and poly silicon as sacrificial layer and cantilever respectively,a poly silicon micromachined RF MEMS(radio frequency microelectronic mechanical system) switch is fabricated.During the fabrica...By using LPCVD SiO 2 and poly silicon as sacrificial layer and cantilever respectively,a poly silicon micromachined RF MEMS(radio frequency microelectronic mechanical system) switch is fabricated.During the fabrication process,the stress of poly silicon is released to prevent poly silicon membrane from bending,and the issue of compatibility between RF switch and IC process technology is also resolved.The low residual tensile stress poly silicon cantilever is obtained by the optimization.The switch is tested,and the preliminary test results show:the pull down voltage is 89V,and the switch speed is about 5μs.The switch provides the potential to build a new fully monolithic integrated RF MEMS for radar and communications applications.展开更多
A micromachined vertical cavity tunable filter with AlGaAs/GaAs distributed Bragg reflector is presented.This filter can be electrostatic tuning over a range of 28nm with an applied voltage of 7V.
A piezoresistive silicon accelerometer fabricated by a selective,self-stopping porous silicon (PS) etching method using an epitaxial layer for movable microstructures is described and analyzed.The technique is capable...A piezoresistive silicon accelerometer fabricated by a selective,self-stopping porous silicon (PS) etching method using an epitaxial layer for movable microstructures is described and analyzed.The technique is capable of constructing a microstructure precisely.PS is used as a sacrificial layer,and releasing holes are etched in the film.TMAH solution with additional Si powder and (NH_4)_2S_2O_8 is used to remove PS through the small releasing holes without eroding uncovered Al.The designed fabrication process is full compatible with standard CMOS process.展开更多
Novel 2×2 torsion-mirror optical switch arrays are fabricated by using the mixed micromachining based on the surface and bulk silicon microelectronics,then are investigated electromechanically in applied direct a...Novel 2×2 torsion-mirror optical switch arrays are fabricated by using the mixed micromachining based on the surface and bulk silicon microelectronics,then are investigated electromechanically in applied direct and alternating electric fields.When the thickness of the elastic torsion beams suspending the aluminum coated polysilicon micro-mirrors of the switches in the arrays is about 1μm,the electrostatic yielding voltages for driving the mirrors to achieve their ON-state are in the range of 270～290V,and the minimum holding voltages for mirrors ON-state are found as 55V or so.Theoretical analysis manifests that the yielding voltage is more sensitive to beam thickness than other design parameters do about the torsion-mirror switch structures.The lifetime can reach 10 8 times.The estimated shortest switching time of the switches at least lasts for less than 2ms.The force analysis on the two kinds of new fiber self-holding structures integrated monolithically in the chip of the optical switch arrays indicates that the structures can feature self-fixing and self-aligning of optical fibers.展开更多
A novel into-plane rotating rnicromirror actuated by a hybrid electrostatic driving structure is presented. The hybrid driving structure is made up of a planar plate drive and a vertical comb drive. The device is fabr...A novel into-plane rotating rnicromirror actuated by a hybrid electrostatic driving structure is presented. The hybrid driving structure is made up of a planar plate drive and a vertical comb drive. The device is fabricated in SOI substrate by using a bulk-and-surface mixed silicon micromachining process. As demonstrated by experiment, the novel driving structure can actuate the mirror to achieve large-range continuous rotation as well as spontaneous 90°rotation induced by the pull-in effect. The continuous rotating range of the micromirror is increased to about 46° at an increased yielding voltage. The measured yielding voltages of the mirrors with torsional springs of 1 and 0.5μm in thickness are 390 - 410V and 140 - 160V, respectively. The optical insertion loss has also been measured to be --1.98dB when the mirror serves as an optical switch.展开更多
The fabrication and simulation of an electromagnetic microrelay are presented based on micro electromechanical systems (MEMS) technique.The microrelay dimensions of about 4mm×4mm×0 5mm are fabricated with t...The fabrication and simulation of an electromagnetic microrelay are presented based on micro electromechanical systems (MEMS) technique.The microrelay dimensions of about 4mm×4mm×0 5mm are fabricated with the common technique of micromachining.Compared with the traditional relays,a planar coil is substituted for a solenoid coil to favor the MEMS fabrication.Moreover,a bi supporter cantilever beam with high sensitivity is fabricated to act as the movable electrode of the microrelay.Theoretical calculations and simulations are also carried out with respect to the electromagnetic force yielded by the exciting electromagnetic coil.The structure and parameters concerning the electromagnetic microrelay can be optimized using the results.展开更多
Research on micro-machines is becoming popular.In this paper,the electric driving behavior of liquid metal columns in confining channel was studied.When the electric field was applied,the liquid metal near the negativ...Research on micro-machines is becoming popular.In this paper,the electric driving behavior of liquid metal columns in confining channel was studied.When the electric field was applied,the liquid metal near the negative electrode became flat,longer.The NaOH electrolyte(1.0 mol/L)could flow from the positive electrode to the negative electrode from a small space above the liquid metal column.Besides,the length and volume of the liquid metal would affect its motion and deformation behavior.Both cylindrical liquid column(R=5 mm,L=5 cm)and linear liquid column(R=5 mm,L=40 cm)exhibit deformable movements,which are similar to the bionic movements of earthworms.The electrically driven liquid metal in closed systems could provide a theoretical basis for droplet actuation in microtubes.It has a very wide application prospect in the field of micro-drive machines.展开更多
Light carries linear momentum and can therefore exert a radiation force on the objects that it encounters. This established fact enabled optical manipulation of micro/nano-sized objects, as well as macroscopic objects...Light carries linear momentum and can therefore exert a radiation force on the objects that it encounters. This established fact enabled optical manipulation of micro/nano-sized objects, as well as macroscopic objects such as solar sails, among many other important applications. While these efforts benefit from the average value of light’s linear momentum, in this article, we propose exploiting the temporal variation of light’s linear momentum to achieve an oscillatory force of microNewton amplitude and picosecond period. We validate our proposal by analytical calculations and time domain simulations of Maxwell’s equations in the case of a high-index quarter-wave slab irradiated by a terahertz plane electromagnetic wave. In particular, we show that for plane wave terahertz light of electric field amplitude 5000 V/m and frequency 4.8 THz, an oscillatory radiation pressure of amplitude 1.8 × 10<sup>-4</sup> N/m<sup>2</sup> and 0.1 ps period can be achieved.展开更多
The application of surface textures has been employed to improve the tribological performance of various mechanical components. Various techniques have been used for the application of surface textures such as micro-d...The application of surface textures has been employed to improve the tribological performance of various mechanical components. Various techniques have been used for the application of surface textures such as micro-dimple arrays, but the fabrication of such arrays on cylindrical inner surfaces remains a challenge. In this study, a dry-film photoresist is used as a mask during through-mask electrochemical micromachining to successfully prepare micro-dimple arrays with dimples 94 lm in diameter and 22.7 lm deep on cylindrical inner surfaces, with a machining time of 9 s and an applied voltage of 8 V. The versatility of this method is demonstrated, as are its potential low cost and high efficiency. It is also shown that for a fixed dimple depth, a smaller dimple diameter can be obtained using a combination of lower current density and longer machining time in a passivating sodium nitrate electrolyte.展开更多
The trend towards miniaturization has increased dramatically over the last decade, especially within the fields concerned with bioengineering, microelectronics, and aerospace. Micromillin8 is among the principal manu-...The trend towards miniaturization has increased dramatically over the last decade, especially within the fields concerned with bioengineering, microelectronics, and aerospace. Micromillin8 is among the principal manu- facturing processes which have allowed the development of components possessing micrometric dimensions, being used to the manufacture of both forming tools and the final product. The aim of this work is to present the principal aspects related to this technology, with emphasis on the work material requirements, tool ma- terials and geometry, cutting forces and temperature, quality of the finished product, process modelling and monitoring and machine tool requirements. It can be noticed that size effect possesses a relevant role with regard to the selection of both work material （grain size） and tooling （edge radius）. Low forces and temper- ature are recorded during micromillin8, however, the specific cutting force may reach high values because of the ploughing effect observed as the uncut chip thickness is reduced. Finally, burr formation is the principal concern with regard to the quality of the finished part.展开更多
Optical waveguides are far more than mere connecting elements in integrated optical systems and circuits.Benefiting from their high optical confinement and miniaturized footprints,waveguide structures established base...Optical waveguides are far more than mere connecting elements in integrated optical systems and circuits.Benefiting from their high optical confinement and miniaturized footprints,waveguide structures established based on crystalline materials,particularly,are opening exciting possibilities and opportunities in photonic chips by facilitating their on-chip integration with different functionalities and highly compact photonic circuits.Femtosecond-laser-direct writing(FsLDW),as a true three-dimensional(3D)micromachining and microfabrication technology,allows rapid prototyping of on-demand waveguide geometries inside transparent materials via localized material modification.The success of FsLDW lies not only in its unsurpassed aptitude for realizing 3D devices but also in its remarkable material-independence that enables cross-platform solutions.This review emphasizes FsLDW fabrication of waveguide structures with 3D layouts in dielectric crystals.Their functionalities as passive and active photonic devices are also demonstrated and discussed.展开更多
Micro-optical electromechanical systems(MOEMS)combine the merits of micro-electromechanical systems(MEMS)and micro-optics to enable unique optical functions for a wide range of advanced applications.Using simple exter...Micro-optical electromechanical systems(MOEMS)combine the merits of micro-electromechanical systems(MEMS)and micro-optics to enable unique optical functions for a wide range of advanced applications.Using simple external electromechanical control methods,such as electrostatic,magnetic or thermal effects,Si-based MOEMS can achieve precise dynamic optical modulation.In this paper,we will briefly review the technologies and applications of Si-based MOEMS.Their basic working principles,advantages,general materials and micromachining fabrication technologies are introduced concisely,followed by research progress of advanced Si-based MOEMS devices,including micromirrors/micromirror arrays,micro-spectrometers,and optical/photonic switches.Owing to the unique advantages of Si-based MOEMS in spatial light modulation and high-speed signal processing,they have several promising applications in optical communications,digital light processing,and optical sensing.Finally,future research and development prospects of Si-based MOEMS are discussed.展开更多
A high friction coefficient and a low wear rate of contacted surfaces are essential elements to friction pairs between the stator and the rotor in ultrasonic motors. It has been shown that surface textures have a sign...A high friction coefficient and a low wear rate of contacted surfaces are essential elements to friction pairs between the stator and the rotor in ultrasonic motors. It has been shown that surface textures have a significant effect on improving the tribological performance of friction pairs.In this paper, microgroove arrays are introduced to the stator surface for improving the tribological performance of friction pairs between the stator and the rotor in ultrasonic motors. Microgrooves were fabricated on a phosphor bronze surface by through-mask electrochemical micromachining（TMEMM）. Parameters, namely, the electrolyte inlet pressure, applied voltage, pulse duty cycle,and frequency, were varied to investigate their influences on the dimensions and morphology of the microgrooves. Results showed that the width and depth of the microgrooves were strongly affected by the applied voltage and frequency, while the morphology of the microgrooves was dependent on the electrolyte inlet pressure and the pulse duty cycle. Compared with a smooth surface, the friction coefficient increased from 0.245 to 0.334 and less abrasion was obtained when a surface was textured with microgrooves of which the width and depth were 185.6 and 57.6 lm,respectively. Microgroove arrays might play an important role in enhancing the performance of ultrasonic motors.展开更多
文摘Long-period fiber gratings have the advantages of small size,corrosion resistance,anti-electro-magnetic interference,and high sensitivity,making them widely used in biomedicine,the power industry,and aerospace.This paper develops a long-period fiber grating sensor based on periodic microchannels.First,a series of linear structures were etched in the cladding of a single-mode fiber by femtosecond laser microma-chining.Then,the laser-modified region was selectively eroded by selective chemical etching to obtain the periodic microchannel structure.Finally,the channels were filled with polydimethylsiloxane(PDMS)to im-prove the spectral quality.The experimental results show that the sensor has good sensitivity in the measure-ment of various parameters such as temperature,stress,refractive index(RI),and bending.It has a temperat-ure sensitivity of−55.19 pm/℃,a strain sensitivity of−3.19 pm/με,a maximum refractive index sensitivity of 540.28 nm/RIU,and a bending sensitivity of 2.65 dB/m^(-1).All of the measurement parameters show good lin-ear responses.The sensor has strong application prospects in the field of precision measurement and sensing.
基金the support by the Harbin Manufacturing Science and Technology Innovation Talent Project(No.2023CXRCGD035)the Open Research Foundation of State Key Laboratory of Digital Manufacturing Equipment and Technology in Huazhong University of Science and Technology,China(No.IMETKF2023012).
文摘While laser surface texturing(LST)is a promising manufacturing technique for surface functionalization,simultaneously realizing high precision and high efficiency in the LST of complex curved surface is challenging,due to continuously varied geometries of laser-matter incidence.In the present work,we propose a novel manufacturing system of 7-axis on-the-fly LST for complex curved surface,based on the integrated synchronization of 5-axis linkage motion platform with 2-axis galvanometer.Specifically,the algorithm for decomposing spatial texture trajectory on curved surface into low-frequency and high-frequency parts is established,based on which the kinematic model of synchronized 7-axis system is developed to derive the motion of each axis in both 5-axis linkage motion platform and 2-axis galvanometer simultaneously.Subsequently,the synchronized 7-axis LST system is experimentally realized,including the setup of mechanical stages integrated with optical path,the configuration of numerical control unit,and the development of processing software.Finally,case study of 7-axis on-the-fly LST of freeform aluminum surface is performed,and the advantages in terms of processing efficiency and texturing accuracy over 5-axis linkage LST are demonstrated.The correlation of reduced following errors between mechanical stages with the promoted performance of curved surface texturing by the 7-axis on-the-fly LST is further analyzed.Current work provides a feasible solution for establishing the manufacturing system for high performance LST of complex curved surface.
基金co-supported the National Natural Science Foundation of China(No.52235010)the Heilongjiang Postdoctoral Fund(No.LBH-Z22136)the New Era Longjiang Excellent Master and Doctoral Dissertation Fund(No.LJYXL2022-057).
文摘To mill fine and well-defined micro-dimpled structures,a machining manner of spiral trajectory tool reciprocating motion,where the tool repeats the process of‘feed milling–retract–cutting feed–feed milling again’along the spiral trajectory,was proposed.From the kinematics analysis,it is found that the machining quality of micro-dimpled structures is highly dependent on the machining trajectory using spiral trajectory tool reciprocating motion.To reveal this causation,simulation modelling and experimental studies were carried out.A simulation model was developed to quantitatively and qualitatively investigate the influence of the trajectory discretization strategies(constant-angle and constant-arc length)and parameters(discrete angle,discrete arc length,and pitch)on surface texture and residual height of micro-dimpled structures.Subsequently,micro-dimpled structures were milled under different trajectory discretization strategies and parameters with spiral trajectory tool reciprocating motion.A comprehensive comparison between the milled results and simulation analysis was made based on geometry accuracy,surface morphology and surface roughness of milled dimples.Meanwhile,the errors and factors affecting the above three aspects were analyzed.The results demonstrate both the feasibility of the established simulation model and the machining capability of this machining way in milling high-quality micro-dimpled structures.Spiral trajectory tool reciprocating motion provides a new machining way for milling micro-dimpled structures and micro-dimpled functional surfaces.And an appropriate machining trajectory can be generated based on the optimized trajectory parameters,thus contributing to the improvement of machining quality and efficiency.
基金This work is supported by the National Natural Science Foundation of China(Nos.51975328,52275348)Taishan Scholar Project of Shandong Province(No.tsqn202306006)Youth Innovation Technology Support Program of Shandong Provincial Universities(No.2022KJ041).
文摘Thin-walled metal parts with functional micro-featured surface have broad application prospects in the fields of resistance reduction,noise reduction,etc.In this study,a novel micro-rolling&incremental sheet forming hybrid process(μR-ISF)is proposed to fabricate thin-walled metal parts with microgroove arrays.An analytical model which relates the rolling force and microgroove depth in the micro-rolling stage was first established.Then,the formation mechanism of microgroove morphology during both micro-rolling stage and macro-shape forming stage are investigated.After the micro-grooved sheet being incrementally formed,a significant reduction(between 21%to nearly 60%)is occurred in the depth of both transverse and longitudinal grooves compared to the flat sheet.Meanwhile,the width of transverse grooves decreases slightly by about 10%on average,while the width of longitudinal microgrooves increases significantly by more than 30%on average.After micro-rolling,85°{102}tensile twins appear on the micro-grooved sheet and the percentage of 65°{112}compressive twins increases.After incremental forming,the percentage of low-angle grain boundaries and the density of geometrically necessary dislocations in the formed part increase significantly,and the grain size distribution becomes more uniform.The present work provides a new strategy for the fabrication of 3D metal thin-walled components with surface micro-features.
基金supported by the National Science Foundation (NSF)under grant number CBET-2110603.
文摘This study presents a comprehensive optimization and comparative analysis of thermoelectric(TE)infrared(IR)detec-tors using Bi_(2)Te_(3) and Si materials.Through theoretical modeling and numerical simulations,we explored the impact of TE mate-rial properties,device structure,and operating conditions on responsivity,detectivity,noise equivalent temperature difference(NETD),and noise equivalent power(NEP).Our study offers an optimally designed IR detector with responsivity and detectivity approaching 2×10^(5) V/W and 6×10^(9) cm∙Hz^(1/2)/W,respectively.This enhancement is attributed to unique design features,includ-ing raised thermal collectors and long suspended thin thermoelectric wire sensing elements embedded in low thermal conductivity organic materials like parylene.Moreover,we demonstrate the compatibility of Bi_(2)Te_(3)-based detector fabrication pro-cesses with existing MEMS foundry processes,facilitating scalability and manufacturability.Importantly,for TE IR detectors,zT/κemerges as a critical parameter contrary to conventional TE material selection based solely on zT(where zT is the thermoelec-tric figure of merit andκis the thermal conductivity).
基金supported by the National Key Research and Development Program of China(2022YFB3205400)the National Natural Science Foundation of China(52275570)+1 种基金the Postdoctoral Innovation Talents Support Program(BX20230288)the Postdoctoral Science Foundation of Shaanxi Province(2018BSHEDZZ08).
文摘Gravimetric resonant-inspired biosensors have attracted increasing attention in industrial and point-ofcare applications,enabling label-free detection of biomarkers such as DNA and antibodies.Capacitive micromachined ultrasonic transducers(CMUTs)are promising tools for developing miniaturized highperformance biosensing complementary metal–oxide–silicon(CMOS)platforms.However,their operability is limited by inefficient functionalization,aggregation,crosstalk in the buffer,and the requirement for an external high-voltage(HV)power supply.In this study,we aimed to propose a CMUTs-based resonant biosensor integrated with a CMOS front–end interface coupled with ethylene–glycol alkanethiols to detect single-stranded DNA oligonucleotides with large specificity.The topography of the functionalized surface was characterized by energy-dispersive X-ray microanalysis.Improved selectivity for onchip hybridization was demonstrated by comparing complementary and non-complementary singlestranded DNA oligonucleotides using fluorescence imaging technology.The sensor array was further characterized using a five-element lumped equivalent model.The 4 mm^(2) application-specific integrated circuit chip was designed and developed through 0.18 lm HV bipolar-CMOS-double diffused metal–oxide–silicon(DMOS)technology(BCD)to generate on-chip 20 V HV boosting and to track feedback frequency under a standard 1.8 V supply,with a total power consumption of 3.8 mW in a continuous mode.The measured results indicated a detection sensitivity of 7.943×10^(-3) lmol·L^(-1)·Hz^(-1) over a concentration range of 1 to 100 lmol·L^(-1).In conclusion,the label-free biosensing of DNA under dry conditions was successfully demonstrated using a microfabricated CMUT array with a 2 MHz frequency on CMOS electronics with an internal HV supplier.Moreover,ethylene–glycol alkanethiols successfully deposited self-assembled monolayers on aluminum electrodes,which has never been attempted thus far on CMUTs,to enhance the selectivity of bio-functionalization.The findings of this study indicate the possibility of full-on-chip DNA biosensing with CMUTs.
基金National Natural Science Foundation of China (50635040)National High-tech Research and Development Program (2009AA04Z302)Jiangsu Provincial Natural Science Foundation (BK2008043)
文摘Electrochemical micromachining （EMM） technology for fabricating micro structures is presented in this article. By applying ultra short pulses, dissolution of a workpiece can be restricted to the region very close to the electrode. First, an EMM system for meeting the requirements of the EMM process is established. Second, sets of experiments is carried out to investigate the influence of some of the predominant electrochemical process parameters such as electrical parameters, feed rate, electrode geometry features and electrolyte composition on machining quality, especially the influences of pulse on time on shape precision and working end shape of electrode on machined surface quality. Finally, after the preliminary experiments, a complex microstructure with good shape precision and surface quality is successfully obtained.
文摘By using LPCVD SiO 2 and poly silicon as sacrificial layer and cantilever respectively,a poly silicon micromachined RF MEMS(radio frequency microelectronic mechanical system) switch is fabricated.During the fabrication process,the stress of poly silicon is released to prevent poly silicon membrane from bending,and the issue of compatibility between RF switch and IC process technology is also resolved.The low residual tensile stress poly silicon cantilever is obtained by the optimization.The switch is tested,and the preliminary test results show:the pull down voltage is 89V,and the switch speed is about 5μs.The switch provides the potential to build a new fully monolithic integrated RF MEMS for radar and communications applications.
文摘A micromachined vertical cavity tunable filter with AlGaAs/GaAs distributed Bragg reflector is presented.This filter can be electrostatic tuning over a range of 28nm with an applied voltage of 7V.
文摘A piezoresistive silicon accelerometer fabricated by a selective,self-stopping porous silicon (PS) etching method using an epitaxial layer for movable microstructures is described and analyzed.The technique is capable of constructing a microstructure precisely.PS is used as a sacrificial layer,and releasing holes are etched in the film.TMAH solution with additional Si powder and (NH_4)_2S_2O_8 is used to remove PS through the small releasing holes without eroding uncovered Al.The designed fabrication process is full compatible with standard CMOS process.
文摘Novel 2×2 torsion-mirror optical switch arrays are fabricated by using the mixed micromachining based on the surface and bulk silicon microelectronics,then are investigated electromechanically in applied direct and alternating electric fields.When the thickness of the elastic torsion beams suspending the aluminum coated polysilicon micro-mirrors of the switches in the arrays is about 1μm,the electrostatic yielding voltages for driving the mirrors to achieve their ON-state are in the range of 270～290V,and the minimum holding voltages for mirrors ON-state are found as 55V or so.Theoretical analysis manifests that the yielding voltage is more sensitive to beam thickness than other design parameters do about the torsion-mirror switch structures.The lifetime can reach 10 8 times.The estimated shortest switching time of the switches at least lasts for less than 2ms.The force analysis on the two kinds of new fiber self-holding structures integrated monolithically in the chip of the optical switch arrays indicates that the structures can feature self-fixing and self-aligning of optical fibers.
文摘A novel into-plane rotating rnicromirror actuated by a hybrid electrostatic driving structure is presented. The hybrid driving structure is made up of a planar plate drive and a vertical comb drive. The device is fabricated in SOI substrate by using a bulk-and-surface mixed silicon micromachining process. As demonstrated by experiment, the novel driving structure can actuate the mirror to achieve large-range continuous rotation as well as spontaneous 90°rotation induced by the pull-in effect. The continuous rotating range of the micromirror is increased to about 46° at an increased yielding voltage. The measured yielding voltages of the mirrors with torsional springs of 1 and 0.5μm in thickness are 390 - 410V and 140 - 160V, respectively. The optical insertion loss has also been measured to be --1.98dB when the mirror serves as an optical switch.
文摘The fabrication and simulation of an electromagnetic microrelay are presented based on micro electromechanical systems (MEMS) technique.The microrelay dimensions of about 4mm×4mm×0 5mm are fabricated with the common technique of micromachining.Compared with the traditional relays,a planar coil is substituted for a solenoid coil to favor the MEMS fabrication.Moreover,a bi supporter cantilever beam with high sensitivity is fabricated to act as the movable electrode of the microrelay.Theoretical calculations and simulations are also carried out with respect to the electromagnetic force yielded by the exciting electromagnetic coil.The structure and parameters concerning the electromagnetic microrelay can be optimized using the results.
基金Natural Science Foundation of Chongqing(Grant Nos.cstc2019jcyj-msxmX0788,cstc2020jcyj-msxmX0925)Science and Technology Research Program of Chongqing Municipal Education Commission China(Grant Nos.KJQN201901342,KJQN202001317).
文摘Research on micro-machines is becoming popular.In this paper,the electric driving behavior of liquid metal columns in confining channel was studied.When the electric field was applied,the liquid metal near the negative electrode became flat,longer.The NaOH electrolyte(1.0 mol/L)could flow from the positive electrode to the negative electrode from a small space above the liquid metal column.Besides,the length and volume of the liquid metal would affect its motion and deformation behavior.Both cylindrical liquid column(R=5 mm,L=5 cm)and linear liquid column(R=5 mm,L=40 cm)exhibit deformable movements,which are similar to the bionic movements of earthworms.The electrically driven liquid metal in closed systems could provide a theoretical basis for droplet actuation in microtubes.It has a very wide application prospect in the field of micro-drive machines.
文摘Light carries linear momentum and can therefore exert a radiation force on the objects that it encounters. This established fact enabled optical manipulation of micro/nano-sized objects, as well as macroscopic objects such as solar sails, among many other important applications. While these efforts benefit from the average value of light’s linear momentum, in this article, we propose exploiting the temporal variation of light’s linear momentum to achieve an oscillatory force of microNewton amplitude and picosecond period. We validate our proposal by analytical calculations and time domain simulations of Maxwell’s equations in the case of a high-index quarter-wave slab irradiated by a terahertz plane electromagnetic wave. In particular, we show that for plane wave terahertz light of electric field amplitude 5000 V/m and frequency 4.8 THz, an oscillatory radiation pressure of amplitude 1.8 × 10<sup>-4</sup> N/m<sup>2</sup> and 0.1 ps period can be achieved.
基金supported by the Joint Funds of the National Natural Science Foundation of China and Guangdong Province(No.U1134003)
文摘The application of surface textures has been employed to improve the tribological performance of various mechanical components. Various techniques have been used for the application of surface textures such as micro-dimple arrays, but the fabrication of such arrays on cylindrical inner surfaces remains a challenge. In this study, a dry-film photoresist is used as a mask during through-mask electrochemical micromachining to successfully prepare micro-dimple arrays with dimples 94 lm in diameter and 22.7 lm deep on cylindrical inner surfaces, with a machining time of 9 s and an applied voltage of 8 V. The versatility of this method is demonstrated, as are its potential low cost and high efficiency. It is also shown that for a fixed dimple depth, a smaller dimple diameter can be obtained using a combination of lower current density and longer machining time in a passivating sodium nitrate electrolyte.
文摘The trend towards miniaturization has increased dramatically over the last decade, especially within the fields concerned with bioengineering, microelectronics, and aerospace. Micromillin8 is among the principal manu- facturing processes which have allowed the development of components possessing micrometric dimensions, being used to the manufacture of both forming tools and the final product. The aim of this work is to present the principal aspects related to this technology, with emphasis on the work material requirements, tool ma- terials and geometry, cutting forces and temperature, quality of the finished product, process modelling and monitoring and machine tool requirements. It can be noticed that size effect possesses a relevant role with regard to the selection of both work material （grain size） and tooling （edge radius）. Low forces and temper- ature are recorded during micromillin8, however, the specific cutting force may reach high values because of the ploughing effect observed as the uncut chip thickness is reduced. Finally, burr formation is the principal concern with regard to the quality of the finished part.
基金financial support from National Natural Science Foundation of China(No.61775120).
文摘Optical waveguides are far more than mere connecting elements in integrated optical systems and circuits.Benefiting from their high optical confinement and miniaturized footprints,waveguide structures established based on crystalline materials,particularly,are opening exciting possibilities and opportunities in photonic chips by facilitating their on-chip integration with different functionalities and highly compact photonic circuits.Femtosecond-laser-direct writing(FsLDW),as a true three-dimensional(3D)micromachining and microfabrication technology,allows rapid prototyping of on-demand waveguide geometries inside transparent materials via localized material modification.The success of FsLDW lies not only in its unsurpassed aptitude for realizing 3D devices but also in its remarkable material-independence that enables cross-platform solutions.This review emphasizes FsLDW fabrication of waveguide structures with 3D layouts in dielectric crystals.Their functionalities as passive and active photonic devices are also demonstrated and discussed.
基金supported by the National Natural Science Foundation of China under Grant No.61975016the Science and Technology Project of Guangdong(2020B010190001)+2 种基金Natural Science Foundation of Beijing Municipality(1212013 and Z190006)Beijing Municipal Science&Technology Commission,Administrative Commission of Zhongguancun Science Park No.Z211100004821009Cultivation Project for Basic Research and Innovation of Yanshan University No.2021LGQN021.
文摘Micro-optical electromechanical systems(MOEMS)combine the merits of micro-electromechanical systems(MEMS)and micro-optics to enable unique optical functions for a wide range of advanced applications.Using simple external electromechanical control methods,such as electrostatic,magnetic or thermal effects,Si-based MOEMS can achieve precise dynamic optical modulation.In this paper,we will briefly review the technologies and applications of Si-based MOEMS.Their basic working principles,advantages,general materials and micromachining fabrication technologies are introduced concisely,followed by research progress of advanced Si-based MOEMS devices,including micromirrors/micromirror arrays,micro-spectrometers,and optical/photonic switches.Owing to the unique advantages of Si-based MOEMS in spatial light modulation and high-speed signal processing,they have several promising applications in optical communications,digital light processing,and optical sensing.Finally,future research and development prospects of Si-based MOEMS are discussed.
基金supported by the National Basic Research Program of China (973 Program,No.2015CB057502)the Fundamental Research Funds for the Central Universities (No.NZ2016106)
文摘A high friction coefficient and a low wear rate of contacted surfaces are essential elements to friction pairs between the stator and the rotor in ultrasonic motors. It has been shown that surface textures have a significant effect on improving the tribological performance of friction pairs.In this paper, microgroove arrays are introduced to the stator surface for improving the tribological performance of friction pairs between the stator and the rotor in ultrasonic motors. Microgrooves were fabricated on a phosphor bronze surface by through-mask electrochemical micromachining（TMEMM）. Parameters, namely, the electrolyte inlet pressure, applied voltage, pulse duty cycle,and frequency, were varied to investigate their influences on the dimensions and morphology of the microgrooves. Results showed that the width and depth of the microgrooves were strongly affected by the applied voltage and frequency, while the morphology of the microgrooves was dependent on the electrolyte inlet pressure and the pulse duty cycle. Compared with a smooth surface, the friction coefficient increased from 0.245 to 0.334 and less abrasion was obtained when a surface was textured with microgrooves of which the width and depth were 185.6 and 57.6 lm,respectively. Microgroove arrays might play an important role in enhancing the performance of ultrasonic motors.
