A novel continuous-flow PCR chip adopting self-heating, passive-cooling mode to realize the DNA fragments amplification was presented. Using the ANSYS finite element analysis, the temperature distribution of the chip ...A novel continuous-flow PCR chip adopting self-heating, passive-cooling mode to realize the DNA fragments amplification was presented. Using the ANSYS finite element analysis, the temperature distribution of the chip is simulated and analyzed.The optimal size of the chip is 30×22 mm2, the roundabout micro-channel is the 90 μm width, 40 μm depth. Two micro-heater with the nickel-chrome alloy material film are formed on the side of silicon belonging to denaturation and renaturation zones needed for PCR reaction, and two adiabatic structures with groove on side of silicon by anisotropy etching. By the mode of heating local zones at single side, three wider constant temperature zones could be formed, which are 60 ℃,72 ℃,95 ℃ and suitable for PCR,and the temperature-difference could be restricted in less than 5 ℃.展开更多
Some optical fiber hydrophones, such as PGC Mach-Zehnder Interferometer, have a birefringence of single mode optical fibers which induce signal fading. Especially, if two optical beams from the optical arms are orthog...Some optical fiber hydrophones, such as PGC Mach-Zehnder Interferometer, have a birefringence of single mode optical fibers which induce signal fading. Especially, if two optical beams from the optical arms are orthogonal, the interferomic signal can’t be detected at all. Here a new method is introduced. This is to translate the detected phase difference into a linearly polarized angle, then detect it, so that polarization inducing signal fading will be avoided. In theory, this problem is solved. Furthermore, the effect on measurement results from optical source fluctuation becomes little when using the polarization technique.展开更多
During the last two decades, III-nitride-based quantum dots(QDs) have attracted great attentions for optoelectronic applications due to their unique electronic properties. In this paper, we first present an overview o...During the last two decades, III-nitride-based quantum dots(QDs) have attracted great attentions for optoelectronic applications due to their unique electronic properties. In this paper, we first present an overview on the techniques of fabrication for III-nitride-based QDs. Then various optoelectronic devices such as QD lasers, QD light-emitting diodes(LEDs), QD infrared photodetectors(QDIPs) and QD intermediate band(QDIB) solar cells(SCs) are discussed. Finally, we focus on the future research directions and how the challenges can be overcome.展开更多
For the first time an anti-shock packaging model of an acoustic-vibration sensor system has been designed by using the shocking isolation principle. The finite element analysis has been applied for design and simulati...For the first time an anti-shock packaging model of an acoustic-vibration sensor system has been designed by using the shocking isolation principle. The finite element analysis has been applied for design and simulation of the model. The effects of Young’s modulus of anti-shock rubber on naturally occurring frequencies of the combination of rubber and an acoustic sensor chip were analyzed. The displacement of the acoustic sensor chip is loaded with force. The results of static analysis and harmonic analysis show that while increasing Young’s modulus of anti-chock rubber, the first five natural frequencies of the package body also increases. Yet the displacement of the acoustic sensor chip around the resonant frequency decreases. The results of static and transient analysis show that the displacement of the acoustic sensor chip decreases with the increase of Young’s modulus of anti-chock rubber being loaded with either transient force or static force at the bottom of the combination of rubber and acoustic sensor chip.展开更多
In this paper the design and implementation of sixth-order lowpass elliptic switched-capacitor filter( SCF) for interface circuit of Micro-Electro-Mechanical System( MEMS) sensor are presented. This work aims to lower...In this paper the design and implementation of sixth-order lowpass elliptic switched-capacitor filter( SCF) for interface circuit of Micro-Electro-Mechanical System( MEMS) sensor are presented. This work aims to lower total harmonic distortion( THD) without deteriorating other performances. After system design in Simulink,the filter is realized in transistor level and finally fabricated in Central Semiconductor Manufacturing Corporation( CSMC) 0.5 μm metal-oxide-semiconductor( CMOS) technology. Typical measured results are: it operates with 25: 1 clock-to-corner frequency ratio and a 10 k Hz maximum corner frequency. The maximum passband ripple is about 0.49 d B and the minimum stopband rejection is 40 d B for the temperature from-20 ℃to 80 ℃. For the 250 k Hz clock frequency setting,given the 1 k Hz,- 8 d BVrms input signal,the measured worst case THD is-64 d B. The active area of the chip is 2.8 mm2 with 8 pads. The analog power dissipation is10 m W from a 5 V power supply.展开更多
Flexible self-cleaning surface-enhanced Raman scattering(SERS)sensors are highly desirable for the detection of various environmental pollutants,including volatile organic compounds(VOCs).However,achieving sensitive d...Flexible self-cleaning surface-enhanced Raman scattering(SERS)sensors are highly desirable for the detection of various environmental pollutants,including volatile organic compounds(VOCs).However,achieving sensitive detection without labeling and ensuring efficient cyclic use remain significant challenges.Herein,we introduce a direct approach to create a versatile Ni_(3)S_(2)/MoS_(2)@Ag@PDMS(PDMS=polydimethylsiloxane)composite SERS substrate using chemical vapor deposition technology.The produced substrate shows outstanding performance,offering extremely low detection sensitivity(1.0×10^(−12)M 4-aminobenzenethiol)and high enhancement factors(approximately 107).The interactions between the rod-shaped Ni_(3)S_(2)/MoS_(2)@Ag heterostructure and the molecules facilitate the transfer of charge,resulting in an increased electric field enhancement of the exciton resonance.This has the dual benefit of providing a self-cleaning effect and enhancing SERS efficiency.Importantly,the substrate enables sensitive detection of VOCs gas molecules without the need for labels,achieving a minimum detectable concentration as low as 1 ppm for o-dichlorobenzene,due to the preconcentration effect of PDMS.Theoretical calculations further explain the combined effect of electromagnetic and chemical enhancement in this composite substrate.By utilizing the developed visual SERS barcode,quick multiple detection and analysis of mixtures can be accomplished.This flexible and versatile SERS technique has significant potential for on-site detection and analysis of environmental pollutants,opening the doors for the development of a wearable in-situ SERS sensing platform.展开更多
Boron nitride nanotube(BNNT) films were synthesized by combining ball milling and thermal chemical vapor deposition(CVD) using nano-Fe3O4 as a catalyst. The as-produced BNNTs have a bamboo-like structure and have ...Boron nitride nanotube(BNNT) films were synthesized by combining ball milling and thermal chemical vapor deposition(CVD) using nano-Fe3O4 as a catalyst. The as-produced BNNTs have a bamboo-like structure and have a diameter in the range of 50~200 nm with an average length of more than 40 mm.Moreover, BNNT nanojunction structures were synthesized. The structure and morphology of the BNNTs were characterized by XRD, SEM, TEM and HRTEM. The possible growth mechanism of BNNTs and BNNT nanojunction structures were proposed. Though the BNNT films were observed, out of our expectation,BNNTs with thin tube wall and small average diameter have not been achieved, and this could be mainly ascribed to the aggregation of the nanoparticle catalyst, resulting in greater catalyst particles during the process of BNNT growth. This result will provide a promising approach to obtain the desired shape of BNNTs and produce branched junctions of BNNTs.展开更多
A micro direct methanol fuel cell(μDMFC) is suitable for use in notebook computers,mobile phones,and other digital products.To resolve the poor mass-transport efficiency problem in the anode flow channel,this paper p...A micro direct methanol fuel cell(μDMFC) is suitable for use in notebook computers,mobile phones,and other digital products.To resolve the poor mass-transport efficiency problem in the anode flow channel,this paper presents an N-inputs-N-outputs parallel flow pattern with rectangular convexes to reinforce methanol mass transport and reduce concentration polarization.The simulation results show that the N-inputs-N-outputs parallel flow channels with the rectangle convexes improve the performance.μDMFCs,which have four anode flow patterns,are fabricated using MEMS(microelectromechanical systems) technology.The experimental results show that the μDMFC with the rectangle convexes has a performance better than previously reported systems,and has a peak power density of 19.96 mW/cm2.The simulation and experimental results are in good agreement.展开更多
4H-SiC based metal-semiconductor-metal (MSM) photodetectors with diverse spacing were designed, fabricated, and characterized, in which nickel Schottky contacts were needed. Current-voltage and spectral responsivity m...4H-SiC based metal-semiconductor-metal (MSM) photodetectors with diverse spacing were designed, fabricated, and characterized, in which nickel Schottky contacts were needed. Current-voltage and spectral responsivity measurements were carried out at room temperature. The fabricated 4 μm-spacing device showed a very low dark current (0.25 pA at 5 V bias voltage), a typical responsivity of 0.103 A/W at 20 V, and a peak re-sponse wavelength at 290 nm. The fabricated devices held a high DUV to visible re-jection ratio of >103.展开更多
This paper proposes a novel bubble model to analyze drag reduction. The relationship between the slip length and air bubble height is discussed. The numerical relationship between the surface contact angle and slip le...This paper proposes a novel bubble model to analyze drag reduction. The relationship between the slip length and air bubble height is discussed. The numerical relationship between the surface contact angle and slip length is obtained using the solid-liquid contact ratio in the Cassie equation. The surface drag reduction ratio i~:creases by 40~ at low velocities when the solid liquid contact ratio decreases from 90% to i0%. An experimental setup to study liquid/solid friction drag is reported. The drag reduction ratio for the superhydrophobic surface tested experimentally is 30^-35~ at low velocities. These results are skailar to the simulation results obtained at low velocities.展开更多
A fourth-order low-distortion low-pass sigma-delta (∑△) modulator is presented for micro-machined inertial sensors. The proposed single-loop single-bit feedback modulator is optimized with a feed-forward path to d...A fourth-order low-distortion low-pass sigma-delta (∑△) modulator is presented for micro-machined inertial sensors. The proposed single-loop single-bit feedback modulator is optimized with a feed-forward path to decrease the nonlinearities and power consumption. The IC is implemented in a standard 0.6 μm CMOS technology and operates at a sampling frequency of 3.846 MHz. The chip area is 2.12 mm^2 with 23 pads. The experimental results indicate a signal-to-noise ratio (SNR) of 100 dB and dynamic range (DR) of 103 dB at an oversampling rate (OSR) of 128 with the input signal amplitude of-3.88 dBFS at 9.8 kHz; the power consumption is 15 raW at a 5 V supply.展开更多
The wettability of boron nitride nanotube (BNNT) films was modified using a combination of pulsed and continuous wave (CW) mode plasma. The combined mode effectively modified the wettability of BNNT films and kept the...The wettability of boron nitride nanotube (BNNT) films was modified using a combination of pulsed and continuous wave (CW) mode plasma. The combined mode effectively modified the wettability of BNNT films and kept the nanostructures intact. The BNNT films changed from superhydrophobic to superhydrophilic after combined mode treatment at 600 W min. In contrast, the contact angle controllable decreased linearly in a controllable way with increasing energy input before eventually becoming superhydrophilic after 1000 W min of CW mode treatment. A high concentration of graft functional groups formed, along with point defects. More point defects formed when using combined modes and higher energy input. Mainly amine functional groups were grafted by combined mode plasma, while the CW mode plasma led to more formation of amide and imine on the BNNTs. Research into controllable wettability and selection of grafted functional groups should enable promising applications of BNNTs in composites and biology in the future.展开更多
A single-loop fourth-order sigma-delta(ΣΔ) interface circuit for a closed-loop micromachined accelerometer is presented.Two additional electronic integrators are cascaded with the micromachined sensing element to ...A single-loop fourth-order sigma-delta(ΣΔ) interface circuit for a closed-loop micromachined accelerometer is presented.Two additional electronic integrators are cascaded with the micromachined sensing element to form a fourth-order loop filter.The three main noise sources affecting the overall system resolution of aΣΔaccelerometer, mechanical noise,electronic noise and quantization noise,are analyzed in detail.Accurate mathematical formulas for electronic and quantization noise are established.The ASIC is fabricated in a 0.5μm two-metal two-poly n-well CMOS process.The test results indicate that the mechanical noise and electronic noise are 1μg/(Hz)^(1/2) and 8μV/(Hz)^(1/2) respectively,and the theoretical models of electronic and quantization noise agree well with the test and simulation results.展开更多
Differential capacitive detection has been widely used in the displacement measurement of the proof mass of vibratory gyroscopes, but it did not achieve high resolutions in angle detection of rotational gyroscopes due...Differential capacitive detection has been widely used in the displacement measurement of the proof mass of vibratory gyroscopes, but it did not achieve high resolutions in angle detection of rotational gyroscopes due to restrictions in structure, theory, and interface circuitry. In this paper, a differential capacitive detection structure is presented to measure the tilt angle of the rotor of a novel rotational gyroscope. A mathematical model is built to study how the structure's capacitance changes with the rotor tilt angles. The relationship between differential capacitance and structural parameters is analyzed, and preliminarily optimized size parameters are adopted. A lownoise readout interface circuit is designed to convert differential capacitance changes to voltage signals. Rate table test results of the gyroscope show that the smallest resolvable tilt angle of the rotor is less than 0.47(0.00013?),and the nonlinearity of the angle detection structure is 0.33%, which can be further improved. The results indicate that the proposed detection structure and the circuitry are helpful for a high accuracy of the gyroscope.展开更多
Hydrogen evolution reaction(HER)catalytic electrodes under actual working conditions show interesting mass transfer behaviors at solid(electrode)/liquid(electrolyte)/gas(hydrogen)three-phase interfaces.These behaviors...Hydrogen evolution reaction(HER)catalytic electrodes under actual working conditions show interesting mass transfer behaviors at solid(electrode)/liquid(electrolyte)/gas(hydrogen)three-phase interfaces.These behaviors are essential for forming a continuous and effective physical contact region between the electrolyte and the electrode and require further detailed understanding.Here,a case study on 1 T-2 H phase molybdenum disulfide(Mo S_(2))/carbon fiber paper(CFP)catalytic electrodes is performed.Rapid gas-liquid mass transfer at the interface for enhancing the working area stability and capillarity for increasing the electrode working area is found.The real scenario,wherein the energy utilization efficiency of the as-prepared non-noble metal catalytic electrode exceeds that of the noble metal catalytic electrode,is disclosed.Specifically,a fluid dynamics model is developed to investigate the behavior mechanism of hydrogen bubbles from generation to desorption on the catalytic electrode surface with different hydrophilic and hydrophobic properties.These new insights and theoretical evidence on the non-negligible three-phase interface behaviors will identify opportunities and motivate future research in high-efficiency,stability,and low-cost HER catalytic electrode development.展开更多
The analyses of MEMS gyroscope interface circuit on thermal noise, 1/f noise and phase noise are made in this paper. A closed-loop differential driving circuit and a low-noise differential detecting circuit based on t...The analyses of MEMS gyroscope interface circuit on thermal noise, 1/f noise and phase noise are made in this paper. A closed-loop differential driving circuit and a low-noise differential detecting circuit based on the high frequency modulation are designed to limit the noise. The interface chip is implemented in a standard0.5 μm CMOS process. The test results show that the resolution of sensitive capacity can reach to 6.47×10^(-20) F at the bandwidth of 60 Hz. The measuring range is ± 200°/s and the nonlinearity is 310 ppm. The output noise density is 5.8°/(h·(Hz)^(1/2)). The angular random walk(allen-variance) is 0.092°/h^(1/2) and the bias instability is 2.63°/h.展开更多
Aligned silica nanowire arrays and silica microflowers were fabricated using boron as the catalyst and under the flow N2 gas. The obtained product had no catalyst contamination. And silica nanowires had long lengths o...Aligned silica nanowire arrays and silica microflowers were fabricated using boron as the catalyst and under the flow N2 gas. The obtained product had no catalyst contamination. And silica nanowires had long lengths of a few hundreds. The growth of nanowire arrays and microflowers was explained using mechanism. Parallel-plate capacitors using silica nanowire mat as the dielectric were fabricated. The silica nanowire capacitor shows a specific capacitance of 0.24 n F/cm~2 at the frequency of 100 Hz. The capacitor is not monotone changing with the frequency. The measurement of mechanical properties shows that the tunneling current increases along with an increase in bending angle of the capacitor.展开更多
基金the National Natural Science Foundation of China(Grant No.60576047)
文摘A novel continuous-flow PCR chip adopting self-heating, passive-cooling mode to realize the DNA fragments amplification was presented. Using the ANSYS finite element analysis, the temperature distribution of the chip is simulated and analyzed.The optimal size of the chip is 30×22 mm2, the roundabout micro-channel is the 90 μm width, 40 μm depth. Two micro-heater with the nickel-chrome alloy material film are formed on the side of silicon belonging to denaturation and renaturation zones needed for PCR reaction, and two adiabatic structures with groove on side of silicon by anisotropy etching. By the mode of heating local zones at single side, three wider constant temperature zones could be formed, which are 60 ℃,72 ℃,95 ℃ and suitable for PCR,and the temperature-difference could be restricted in less than 5 ℃.
文摘Some optical fiber hydrophones, such as PGC Mach-Zehnder Interferometer, have a birefringence of single mode optical fibers which induce signal fading. Especially, if two optical beams from the optical arms are orthogonal, the interferomic signal can’t be detected at all. Here a new method is introduced. This is to translate the detected phase difference into a linearly polarized angle, then detect it, so that polarization inducing signal fading will be avoided. In theory, this problem is solved. Furthermore, the effect on measurement results from optical source fluctuation becomes little when using the polarization technique.
文摘During the last two decades, III-nitride-based quantum dots(QDs) have attracted great attentions for optoelectronic applications due to their unique electronic properties. In this paper, we first present an overview on the techniques of fabrication for III-nitride-based QDs. Then various optoelectronic devices such as QD lasers, QD light-emitting diodes(LEDs), QD infrared photodetectors(QDIPs) and QD intermediate band(QDIB) solar cells(SCs) are discussed. Finally, we focus on the future research directions and how the challenges can be overcome.
基金Sponsored by the Creativity Ability Fund Project for Cadreman of General Provincial University of Heilongjiang(Grant No.1053G033).
文摘For the first time an anti-shock packaging model of an acoustic-vibration sensor system has been designed by using the shocking isolation principle. The finite element analysis has been applied for design and simulation of the model. The effects of Young’s modulus of anti-shock rubber on naturally occurring frequencies of the combination of rubber and an acoustic sensor chip were analyzed. The displacement of the acoustic sensor chip is loaded with force. The results of static analysis and harmonic analysis show that while increasing Young’s modulus of anti-chock rubber, the first five natural frequencies of the package body also increases. Yet the displacement of the acoustic sensor chip around the resonant frequency decreases. The results of static and transient analysis show that the displacement of the acoustic sensor chip decreases with the increase of Young’s modulus of anti-chock rubber being loaded with either transient force or static force at the bottom of the combination of rubber and acoustic sensor chip.
基金Sponsored by the Fundamental Research Funds for the Central Universities(Grant No.HIT.NSRIF.2013040)
文摘In this paper the design and implementation of sixth-order lowpass elliptic switched-capacitor filter( SCF) for interface circuit of Micro-Electro-Mechanical System( MEMS) sensor are presented. This work aims to lower total harmonic distortion( THD) without deteriorating other performances. After system design in Simulink,the filter is realized in transistor level and finally fabricated in Central Semiconductor Manufacturing Corporation( CSMC) 0.5 μm metal-oxide-semiconductor( CMOS) technology. Typical measured results are: it operates with 25: 1 clock-to-corner frequency ratio and a 10 k Hz maximum corner frequency. The maximum passband ripple is about 0.49 d B and the minimum stopband rejection is 40 d B for the temperature from-20 ℃to 80 ℃. For the 250 k Hz clock frequency setting,given the 1 k Hz,- 8 d BVrms input signal,the measured worst case THD is-64 d B. The active area of the chip is 2.8 mm2 with 8 pads. The analog power dissipation is10 m W from a 5 V power supply.
基金the financial support by State Key Laboratory of Urban Water Resource and Environment(Harbin Institute of Technology)(No.2022TS19)Funding for School-level Research Projects of Yancheng Institute of Technology(No.xjr2021055).
文摘Flexible self-cleaning surface-enhanced Raman scattering(SERS)sensors are highly desirable for the detection of various environmental pollutants,including volatile organic compounds(VOCs).However,achieving sensitive detection without labeling and ensuring efficient cyclic use remain significant challenges.Herein,we introduce a direct approach to create a versatile Ni_(3)S_(2)/MoS_(2)@Ag@PDMS(PDMS=polydimethylsiloxane)composite SERS substrate using chemical vapor deposition technology.The produced substrate shows outstanding performance,offering extremely low detection sensitivity(1.0×10^(−12)M 4-aminobenzenethiol)and high enhancement factors(approximately 107).The interactions between the rod-shaped Ni_(3)S_(2)/MoS_(2)@Ag heterostructure and the molecules facilitate the transfer of charge,resulting in an increased electric field enhancement of the exciton resonance.This has the dual benefit of providing a self-cleaning effect and enhancing SERS efficiency.Importantly,the substrate enables sensitive detection of VOCs gas molecules without the need for labels,achieving a minimum detectable concentration as low as 1 ppm for o-dichlorobenzene,due to the preconcentration effect of PDMS.Theoretical calculations further explain the combined effect of electromagnetic and chemical enhancement in this composite substrate.By utilizing the developed visual SERS barcode,quick multiple detection and analysis of mixtures can be accomplished.This flexible and versatile SERS technique has significant potential for on-site detection and analysis of environmental pollutants,opening the doors for the development of a wearable in-situ SERS sensing platform.
基金supported by the National Natural Science Funds of China (No. 61404036)the National Basic Research Program of China (No. 2012CB934104)the Fundamental Research Funds for the Central Universities (Nos. HIT.NSRIF. 2015039, 01508536)
文摘Boron nitride nanotube(BNNT) films were synthesized by combining ball milling and thermal chemical vapor deposition(CVD) using nano-Fe3O4 as a catalyst. The as-produced BNNTs have a bamboo-like structure and have a diameter in the range of 50~200 nm with an average length of more than 40 mm.Moreover, BNNT nanojunction structures were synthesized. The structure and morphology of the BNNTs were characterized by XRD, SEM, TEM and HRTEM. The possible growth mechanism of BNNTs and BNNT nanojunction structures were proposed. Though the BNNT films were observed, out of our expectation,BNNTs with thin tube wall and small average diameter have not been achieved, and this could be mainly ascribed to the aggregation of the nanoparticle catalyst, resulting in greater catalyst particles during the process of BNNT growth. This result will provide a promising approach to obtain the desired shape of BNNTs and produce branched junctions of BNNTs.
基金supported by the National Natural Science Foundation of China (60806037 and 61076105)the National High-Tech Research & Development Program of China (2006AA04Z353)+1 种基金the Natural Science Research Innovation Foundation of the Harbin Institute of Technology (HIT. NSRIF. 2009008)the Key Laboratory Opening Funding of Key Laboratory of Micro-Systems and Micro-Structures Manufacturing of the Ministry of Education (HIT. KLOF. 2009003)
文摘A micro direct methanol fuel cell(μDMFC) is suitable for use in notebook computers,mobile phones,and other digital products.To resolve the poor mass-transport efficiency problem in the anode flow channel,this paper presents an N-inputs-N-outputs parallel flow pattern with rectangular convexes to reinforce methanol mass transport and reduce concentration polarization.The simulation results show that the N-inputs-N-outputs parallel flow channels with the rectangle convexes improve the performance.μDMFCs,which have four anode flow patterns,are fabricated using MEMS(microelectromechanical systems) technology.The experimental results show that the μDMFC with the rectangle convexes has a performance better than previously reported systems,and has a peak power density of 19.96 mW/cm2.The simulation and experimental results are in good agreement.
文摘4H-SiC based metal-semiconductor-metal (MSM) photodetectors with diverse spacing were designed, fabricated, and characterized, in which nickel Schottky contacts were needed. Current-voltage and spectral responsivity measurements were carried out at room temperature. The fabricated 4 μm-spacing device showed a very low dark current (0.25 pA at 5 V bias voltage), a typical responsivity of 0.103 A/W at 20 V, and a peak re-sponse wavelength at 290 nm. The fabricated devices held a high DUV to visible re-jection ratio of >103.
文摘This paper proposes a novel bubble model to analyze drag reduction. The relationship between the slip length and air bubble height is discussed. The numerical relationship between the surface contact angle and slip length is obtained using the solid-liquid contact ratio in the Cassie equation. The surface drag reduction ratio i~:creases by 40~ at low velocities when the solid liquid contact ratio decreases from 90% to i0%. An experimental setup to study liquid/solid friction drag is reported. The drag reduction ratio for the superhydrophobic surface tested experimentally is 30^-35~ at low velocities. These results are skailar to the simulation results obtained at low velocities.
基金supported by the National Natural Science Foundation of China(No.61204121)
文摘A fourth-order low-distortion low-pass sigma-delta (∑△) modulator is presented for micro-machined inertial sensors. The proposed single-loop single-bit feedback modulator is optimized with a feed-forward path to decrease the nonlinearities and power consumption. The IC is implemented in a standard 0.6 μm CMOS technology and operates at a sampling frequency of 3.846 MHz. The chip area is 2.12 mm^2 with 23 pads. The experimental results indicate a signal-to-noise ratio (SNR) of 100 dB and dynamic range (DR) of 103 dB at an oversampling rate (OSR) of 128 with the input signal amplitude of-3.88 dBFS at 9.8 kHz; the power consumption is 15 raW at a 5 V supply.
基金supported by the National Basic Research Program of China (2012CB934104)the National Natural Science Foundation of China (61071037)
文摘The wettability of boron nitride nanotube (BNNT) films was modified using a combination of pulsed and continuous wave (CW) mode plasma. The combined mode effectively modified the wettability of BNNT films and kept the nanostructures intact. The BNNT films changed from superhydrophobic to superhydrophilic after combined mode treatment at 600 W min. In contrast, the contact angle controllable decreased linearly in a controllable way with increasing energy input before eventually becoming superhydrophilic after 1000 W min of CW mode treatment. A high concentration of graft functional groups formed, along with point defects. More point defects formed when using combined modes and higher energy input. Mainly amine functional groups were grafted by combined mode plasma, while the CW mode plasma led to more formation of amide and imine on the BNNTs. Research into controllable wettability and selection of grafted functional groups should enable promising applications of BNNTs in composites and biology in the future.
基金supported by the National High Technology Research and Development Program of China(No.2008AA042201).
文摘A single-loop fourth-order sigma-delta(ΣΔ) interface circuit for a closed-loop micromachined accelerometer is presented.Two additional electronic integrators are cascaded with the micromachined sensing element to form a fourth-order loop filter.The three main noise sources affecting the overall system resolution of aΣΔaccelerometer, mechanical noise,electronic noise and quantization noise,are analyzed in detail.Accurate mathematical formulas for electronic and quantization noise are established.The ASIC is fabricated in a 0.5μm two-metal two-poly n-well CMOS process.The test results indicate that the mechanical noise and electronic noise are 1μg/(Hz)^(1/2) and 8μV/(Hz)^(1/2) respectively,and the theoretical models of electronic and quantization noise agree well with the test and simulation results.
基金Project supported by the National Natural Basic Research Program(973)of China(No.2012CB934104)the National Natural Science Foundation of China(No.61071037)the Natural Science Foundation of Heilongjiang Province,China(No.F201418)
文摘Differential capacitive detection has been widely used in the displacement measurement of the proof mass of vibratory gyroscopes, but it did not achieve high resolutions in angle detection of rotational gyroscopes due to restrictions in structure, theory, and interface circuitry. In this paper, a differential capacitive detection structure is presented to measure the tilt angle of the rotor of a novel rotational gyroscope. A mathematical model is built to study how the structure's capacitance changes with the rotor tilt angles. The relationship between differential capacitance and structural parameters is analyzed, and preliminarily optimized size parameters are adopted. A lownoise readout interface circuit is designed to convert differential capacitance changes to voltage signals. Rate table test results of the gyroscope show that the smallest resolvable tilt angle of the rotor is less than 0.47(0.00013?),and the nonlinearity of the angle detection structure is 0.33%, which can be further improved. The results indicate that the proposed detection structure and the circuitry are helpful for a high accuracy of the gyroscope.
基金supported by the National Natural Science Foundation of China(No.62004051)the Natural Science Foundation of Heilongjiang province(No.LH2020F013)+1 种基金the China Postdoctoral Science Fund(No.2020M670909)the Heilongjiang Postdoctoral Science Fund(No.LBH-Z19017)。
文摘Hydrogen evolution reaction(HER)catalytic electrodes under actual working conditions show interesting mass transfer behaviors at solid(electrode)/liquid(electrolyte)/gas(hydrogen)three-phase interfaces.These behaviors are essential for forming a continuous and effective physical contact region between the electrolyte and the electrode and require further detailed understanding.Here,a case study on 1 T-2 H phase molybdenum disulfide(Mo S_(2))/carbon fiber paper(CFP)catalytic electrodes is performed.Rapid gas-liquid mass transfer at the interface for enhancing the working area stability and capillarity for increasing the electrode working area is found.The real scenario,wherein the energy utilization efficiency of the as-prepared non-noble metal catalytic electrode exceeds that of the noble metal catalytic electrode,is disclosed.Specifically,a fluid dynamics model is developed to investigate the behavior mechanism of hydrogen bubbles from generation to desorption on the catalytic electrode surface with different hydrophilic and hydrophobic properties.These new insights and theoretical evidence on the non-negligible three-phase interface behaviors will identify opportunities and motivate future research in high-efficiency,stability,and low-cost HER catalytic electrode development.
基金supported by the National Natural Science Foundation of China(No.61204121)the National Hi-Tech Research and Development Program of China(No.2013AA041107)the Fundamental Research Funds for the Central Universities(No.HIT.NSRIF.2013040)
文摘The analyses of MEMS gyroscope interface circuit on thermal noise, 1/f noise and phase noise are made in this paper. A closed-loop differential driving circuit and a low-noise differential detecting circuit based on the high frequency modulation are designed to limit the noise. The interface chip is implemented in a standard0.5 μm CMOS process. The test results show that the resolution of sensitive capacity can reach to 6.47×10^(-20) F at the bandwidth of 60 Hz. The measuring range is ± 200°/s and the nonlinearity is 310 ppm. The output noise density is 5.8°/(h·(Hz)^(1/2)). The angular random walk(allen-variance) is 0.092°/h^(1/2) and the bias instability is 2.63°/h.
基金Project supported by the National Basic Research Program of China (No. 2012CB934104), the National Natural Science Foundation of China (No. 61474034), the Natural Science Foundation of Heilongjiang Province of China (No. F201418), and the Fundamental Research Funds for the Central Universities, China (Nos. HIT.NSRIF. 2014040 and HIT.NSRIF.2013040)
基金financially supported by the National Natural Science Foundation of China (No. 61404036)the National Basic Research Program of China (No. 2012CB934104)+1 种基金the Fundamental Research Funds for the Central Universities (Nos. HIT. NSRIF.2015039, 01508536)State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology (No. 2016 TS 06)
文摘Aligned silica nanowire arrays and silica microflowers were fabricated using boron as the catalyst and under the flow N2 gas. The obtained product had no catalyst contamination. And silica nanowires had long lengths of a few hundreds. The growth of nanowire arrays and microflowers was explained using mechanism. Parallel-plate capacitors using silica nanowire mat as the dielectric were fabricated. The silica nanowire capacitor shows a specific capacitance of 0.24 n F/cm~2 at the frequency of 100 Hz. The capacitor is not monotone changing with the frequency. The measurement of mechanical properties shows that the tunneling current increases along with an increase in bending angle of the capacitor.