Microbridge testing is used to measure the Young's modulus and residual stresses of metallic films.Nickel film microbridges with widths of several hundred microns are fabricated by Microelectromechanical Systems.I...Microbridge testing is used to measure the Young's modulus and residual stresses of metallic films.Nickel film microbridges with widths of several hundred microns are fabricated by Microelectromechanical Systems.In order to measure the mechanical properties of nickel film microbridges,special shaft structure is designed to solve the problem of getting the load--deflection curves of metal film microbridge by Nanoin--denter XP system with normal Berkovich probe.Theoretical analysis of the micro--bridge load--deflection curve is proposed to evaluate the Young's modulus and residual stress of the films simultaneously.The calculated results based on the experimental measurements show that the average Young's modulus and residual stress are around 190GPa and 175MPa respectively,while the Young's modulus measured by Nano-hardness method on nickel film with silicon substrate is 186.8±7.34GPa.展开更多
Bioactive ceramics have been used in bone tissue repair and regeneration.However,because of the complex in vivo osteogenesis process,long cycle,and difficulty of accurately tracking,the mechanism of interaction betwee...Bioactive ceramics have been used in bone tissue repair and regeneration.However,because of the complex in vivo osteogenesis process,long cycle,and difficulty of accurately tracking,the mechanism of interaction between materials and cells has yet to be fully understood,hindering its development.The ceramic microbridge micro-fluidic chip system may solve the problem and provide an in vitro method to simulate the microenvironment in vivo.Nevertheless,the complex microenvironment parameters of the chip system need to be studied in detail.Computer simulation bionics can provide clues for the setting of microenvironment parameters.This study used a computational bionic model to simulate the bone growth process in the presence of immune-related factors.The osteoblast differentiation of mesenchymal stem cells of calcium phosphate ceramics in a macrophage-dominated immune microenvironment was studied using a microfluidic chip system.The computational biomimetic model and microfluidic chip findings were basically consistent with the reported results of the animal experiments.These findings suggest that studying the osteogenic behavior of calcium phosphate ceramics using a microfluidic chip model is feasible.The method model provided in this study can be extended to other biomaterials,providing a viable path for their research and evaluation.展开更多
Based on Ginzburg-Landau theory,we investigate the electromagnetic properties of two-band superconductors with broken time-reversal symmetry.We propose an apparatus of a superconducting ring integrated with a microbri...Based on Ginzburg-Landau theory,we investigate the electromagnetic properties of two-band superconductors with broken time-reversal symmetry.We propose an apparatus of a superconducting ring integrated with a microbridge structure to probe the peculiar topological excitations in the chiral system.The phase difference of two order parameters in the superconductor satisfies the double sine-Gordon equation,and a linear relationship between the phase difference at the two ends of the junction and the total magnetic flux in the ring can be obtained.Then with the Josephson current-phase relation,we establish the dependence of the circulating current and magnetic flux on the applied external magnetic field.Our results show that this single-junction system will exhibit the irreversible behaviors and two different types of fractional flux transitions can clearly manifest the time-reversal symmetry breaking in two-component superconductors.展开更多
In order to balance the compressive stress of a silicon dioxide film and compose a steady MEMS structure, a silicon-rich silicon nitride film with tensile stress is deposited by plasma enhanced chemical vapor depositi...In order to balance the compressive stress of a silicon dioxide film and compose a steady MEMS structure, a silicon-rich silicon nitride film with tensile stress is deposited by plasma enhanced chemical vapor deposition process. Accurately measuring the thermal conductivity of the film is highly desirable in order to design, simulate and optimize MEMS devices. In this paper, a Si02/SixNy bimaterial microbridge structure is presented to measure the thermal conductivity of the silicon-rich silicon nitride film by single steady-state measurement. The thermal conductivity is extracted as 3.25 W/（m-K）. Low thermal conductivity indicates that the silicon-rich silicon nitride film can still be utilized as thermally insulating material in thermal sensors although its thermal conductivity is slightly larger than the values reported in literature.展开更多
A Cr film with a 75 nm thickness sputtered on a Si substrate was used to fabricate microbridge and microcantilever samples with the MEMS （microelectromechanical system） technique. The profile of the buckled beams wa...A Cr film with a 75 nm thickness sputtered on a Si substrate was used to fabricate microbridge and microcantilever samples with the MEMS （microelectromechanical system） technique. The profile of the buckled beams was measured by using the interference technique with white light and fitted with a theoretical result. The uniform residual strain in the bridge samples was deduced from the variation of buckling amplitude with the beam length. On the other hand, the gradient residual strain was determined from the deflection profile of the cantilever. The residual uniform and gradient strain in the Cr film are about 4.96×10^-3 and 4.2967×10^-5, respectively.展开更多
A novel micromechanical bridge-shaped voltage-controlled oscillator with high Q value was fabricated. The core of this kind of oscillators is an electrothermally excited and piezoresistively detected micromechanical b...A novel micromechanical bridge-shaped voltage-controlled oscillator with high Q value was fabricated. The core of this kind of oscillators is an electrothermally excited and piezoresistively detected micromechanical bridge resonator. Its resonance frequency can be adjusted by changing the DC voltage applied to the Wheatstone bridge. Theoretical analysis and experimental data show that its resonance frequency is linear with the square of the DC voltage. The linearity is better than 0.16% and the adjustable frequency range excels 17.15%.展开更多
基金This work was supported by the National Key Fundamental Research and Development Program(No.G1999033103),The measurements were conducted at the State Key Laboratory of Nonlinear Mechanics(LNM),Institute of Mechanics,Chinese Academy of Sciences.
文摘Microbridge testing is used to measure the Young's modulus and residual stresses of metallic films.Nickel film microbridges with widths of several hundred microns are fabricated by Microelectromechanical Systems.In order to measure the mechanical properties of nickel film microbridges,special shaft structure is designed to solve the problem of getting the load--deflection curves of metal film microbridge by Nanoin--denter XP system with normal Berkovich probe.Theoretical analysis of the micro--bridge load--deflection curve is proposed to evaluate the Young's modulus and residual stress of the films simultaneously.The calculated results based on the experimental measurements show that the average Young's modulus and residual stress are around 190GPa and 175MPa respectively,while the Young's modulus measured by Nano-hardness method on nickel film with silicon substrate is 186.8±7.34GPa.
基金supported by the National key research and development programs of China:2022YFC2405800Beijing Natural Science Foundation:L234022supported by China NMPA Research on performance and safety evaluation of innovative biomaterial medical devices:RS2024X004.
文摘Bioactive ceramics have been used in bone tissue repair and regeneration.However,because of the complex in vivo osteogenesis process,long cycle,and difficulty of accurately tracking,the mechanism of interaction between materials and cells has yet to be fully understood,hindering its development.The ceramic microbridge micro-fluidic chip system may solve the problem and provide an in vitro method to simulate the microenvironment in vivo.Nevertheless,the complex microenvironment parameters of the chip system need to be studied in detail.Computer simulation bionics can provide clues for the setting of microenvironment parameters.This study used a computational bionic model to simulate the bone growth process in the presence of immune-related factors.The osteoblast differentiation of mesenchymal stem cells of calcium phosphate ceramics in a macrophage-dominated immune microenvironment was studied using a microfluidic chip system.The computational biomimetic model and microfluidic chip findings were basically consistent with the reported results of the animal experiments.These findings suggest that studying the osteogenic behavior of calcium phosphate ceramics using a microfluidic chip model is feasible.The method model provided in this study can be extended to other biomaterials,providing a viable path for their research and evaluation.
文摘Based on Ginzburg-Landau theory,we investigate the electromagnetic properties of two-band superconductors with broken time-reversal symmetry.We propose an apparatus of a superconducting ring integrated with a microbridge structure to probe the peculiar topological excitations in the chiral system.The phase difference of two order parameters in the superconductor satisfies the double sine-Gordon equation,and a linear relationship between the phase difference at the two ends of the junction and the total magnetic flux in the ring can be obtained.Then with the Josephson current-phase relation,we establish the dependence of the circulating current and magnetic flux on the applied external magnetic field.Our results show that this single-junction system will exhibit the irreversible behaviors and two different types of fractional flux transitions can clearly manifest the time-reversal symmetry breaking in two-component superconductors.
基金supported by the National Natural Science Foundation of China(No.61076110)the Zhejiang Key Discipline of Instrument Science and Technology(No.JL130101)
文摘In order to balance the compressive stress of a silicon dioxide film and compose a steady MEMS structure, a silicon-rich silicon nitride film with tensile stress is deposited by plasma enhanced chemical vapor deposition process. Accurately measuring the thermal conductivity of the film is highly desirable in order to design, simulate and optimize MEMS devices. In this paper, a Si02/SixNy bimaterial microbridge structure is presented to measure the thermal conductivity of the silicon-rich silicon nitride film by single steady-state measurement. The thermal conductivity is extracted as 3.25 W/（m-K）. Low thermal conductivity indicates that the silicon-rich silicon nitride film can still be utilized as thermally insulating material in thermal sensors although its thermal conductivity is slightly larger than the values reported in literature.
基金supported by the National Natural Sci-ence Foundation of China (No. 10402023)
文摘A Cr film with a 75 nm thickness sputtered on a Si substrate was used to fabricate microbridge and microcantilever samples with the MEMS （microelectromechanical system） technique. The profile of the buckled beams was measured by using the interference technique with white light and fitted with a theoretical result. The uniform residual strain in the bridge samples was deduced from the variation of buckling amplitude with the beam length. On the other hand, the gradient residual strain was determined from the deflection profile of the cantilever. The residual uniform and gradient strain in the Cr film are about 4.96×10^-3 and 4.2967×10^-5, respectively.
基金This work supported by the National Natural Science Foundation of China(Grant No.60036016)by National 863 Project of China under Grant No.2001AA313090.
文摘A novel micromechanical bridge-shaped voltage-controlled oscillator with high Q value was fabricated. The core of this kind of oscillators is an electrothermally excited and piezoresistively detected micromechanical bridge resonator. Its resonance frequency can be adjusted by changing the DC voltage applied to the Wheatstone bridge. Theoretical analysis and experimental data show that its resonance frequency is linear with the square of the DC voltage. The linearity is better than 0.16% and the adjustable frequency range excels 17.15%.
