We present a new analytical model for electrostatically actuated microbeams to explore the size effect by using the modified couple stress theory and the minimum total potential energy principle. A material length sca...We present a new analytical model for electrostatically actuated microbeams to explore the size effect by using the modified couple stress theory and the minimum total potential energy principle. A material length scale parameter is introduced to represent the size-dependent characteristics of microbeams. This model also accounts for the nonlinearities associated with the mid-plane stretching force and the electrostatical force. Numerical analysis for microbeams with clamped-clamped and cantilevered conditions has been performed. It is found that the intensity of size effect is closely associated with the thickness of the microbeam,and smaller beam thickness displays stronger size effect and hence yields smaller deffection and larger pull-in voltage. When the beam thickness is comparable to the material length scale parameter,the size effect is significant and the present theoretical model including the material length scale parameter is adequate for predicting the static behavior of microbeam-based MEMS.展开更多
Non-spherical of rotor was described with solution method. Electrostatically suspended gyroscope＇s hollow spherical rotor＇s structure was presented. The simulative analysis of static deformation, dynamic deformation...Non-spherical of rotor was described with solution method. Electrostatically suspended gyroscope＇s hollow spherical rotor＇s structure was presented. The simulative analysis of static deformation, dynamic deformation and synthesize deformation of rotor under different working conditions using the finite element software were carried out. Its deformation law and volume were obtained. The structural parameters of the rotor were optimized. The value of pressure required when the rotor was machined was calculated. The analysis has important theoretical reference value to the design for hollow spherical rotor in electrostatically suspended gyroscope.展开更多
The aggregation behavior of a cationic fluorescence probe 10-（4,7,10,13,16-pentaoxa- 1-azacyclooctadecylmethyl）anthracen-9-ylmethyl dodecanoate （1） was observed and studied by a fluorescence methodology in acidic ...The aggregation behavior of a cationic fluorescence probe 10-（4,7,10,13,16-pentaoxa- 1-azacyclooctadecylmethyl）anthracen-9-ylmethyl dodecanoate （1） was observed and studied by a fluorescence methodology in acidic and neutral conditions. By using the Py scale, differences between simple aggregates and micelles have been discussed. The stability of simple aggregates was discussed in terms of hydrophobic interaction and electrostatic repulsion. The absence of excimer emission of the anthrancene moiety of probe 1 in neutral condition was attributed to the photoinduced electron transfer mechanism instead of photodimerization.展开更多
The electrostatically self-assembly method is getting strategically important to prepare multilayer thin films. With careful choice of component materials, this method should allow for the preparation of multilayer th...The electrostatically self-assembly method is getting strategically important to prepare multilayer thin films. With careful choice of component materials, this method should allow for the preparation of multilayer thin films with a variety of excellent technological properties. Ti02/PSS multilayer thin films with ordered structure were prepared by electrostatic self-assembly method. UV-Vis-NIR spectrophotometer, X-ray photoelectron spectroscopy (XPS), and atom force microscopy (AFM) were used to characterize the structure and performance of the multilayer films. Because electrostatically self-assembly method allows molecular-level control over the film composition and thickness, this paper studied the responding depth of photocatalytic activity of Ti02 self-assembled films in detail.展开更多
A micromachined electrostatically suspended gyroscope(MESG)based on UV-LIGA microfabrication process was introduced.By close-loop control,the suspended rotor is kept in null position and through the torque rebalance l...A micromachined electrostatically suspended gyroscope(MESG)based on UV-LIGA microfabrication process was introduced.By close-loop control,the suspended rotor is kept in null position and through the torque rebalance loop,in which the output control voltages reflects the input angular velocity,a dual-axis input angular velocity can be measured simultaneously.First,the system model of MESG was established by dynamic analysis based on the torque analysis.Then,the rebalance loop under ideal condition is designed using modern control technique.The performance of the designed decoupling rebalance loop was compared with that of conventional proportional integral differential(PID)rebalance loop combined with the compensation loop.In order to realize the decoupling of the output voltages,a compensated decoupling matrix and its difference equation were presented and realized by a digital decoupling method employing digital signal processor(DSP).It was confirmed that the controller could realize the complete decoupling and improve the performance of the gyroscope,which includes merits of fast response speed,low overshoot and good dynamic performance,as the simulation results shown.At last,the circuit and digital realization scheme were given.展开更多
For the electrostatically suspended gyro （ESG） with solid rotor, because the equatorial photoelectric sensor won＇t sense the equatorial marking line and output the correct damping control information when the nutat...For the electrostatically suspended gyro （ESG） with solid rotor, because the equatorial photoelectric sensor won＇t sense the equatorial marking line and output the correct damping control information when the nutation angle is small, the active damping with equatorial marking line will bring considerable error. The passive damping method by applying strong DC magnetic field requires too much time. So an active damping method by longitude marking lines is proposed to fulfill the fine damping for solid ESG rotor. The shape of rotor marking lines and the principle of fine damping are introduced. The simulation results prove that this fine damping method can effectively solve the problem of damping error introduced by active damping with equatorial marking line. The estimating resuits for damping time indicate that the fine damping time is less than 10 percent of passive damping time.展开更多
The coaggregating behavior of the cationic kinetic probe P16;with different types of surfactants are in complete agreement with predictions based on the newly proposed ESAg concept.
A research on the electrostatic torques in the electrostatically suspended gyroscope (ESG) that uses the mass-unbalance modulation (MUM) scheme (MUM-ESG) to sense the direction of the rotor's spinning axis is pres...A research on the electrostatic torques in the electrostatically suspended gyroscope (ESG) that uses the mass-unbalance modulation (MUM) scheme (MUM-ESG) to sense the direction of the rotor's spinning axis is presented here. Spherical harmonic functions are used to describe the asphericity of the rotor and the electrodes. Rotational matrix theory in quantum mechanics is utilized to transform the description of the rotor's asphericity from the rotor-fixed frame into the cavity-fixed frame. And the principle of the virtual displacement is applied to find out the electrostatic torques acting on the rotor. Analytical expressions of the electrostatic torques indicate that there are only three kinds of factors need to be considered when looking for the electrostatic torques in the MUM-ESG. The factors are the asphericity of the rotor, the eccentric rotation of the rotor, and the coupling between the rotor's translational displacement and asphericity. An intuitionistic explanation for the electrostatic torque that comes of the rotor's eccentric rotation is presented also. The effects of these conclusions should be tested and verified in the future experiments and applications.展开更多
Hydr hobie一lipophilic interactions(HLI)will start to bri about the formationof simple aggregates(Ag,s)and eoa egates(CoAg,s)from neutral organie moleeuleswhich possess at least onefl ble chain with more than seven eH...Hydr hobie一lipophilic interactions(HLI)will start to bri about the formationof simple aggregates(Ag,s)and eoa egates(CoAg,s)from neutral organie moleeuleswhich possess at least onefl ble chain with more than seven eHZ grou ,1,2 at theeritieala egate eoncentration展开更多
The average aggregate number(N)of electrostatically stabilized aggregate(ESAg)composed of oppositely-charged long-chain molecules,i.e., sodium ω-[α-(nathphyl)ethoxyl]undecanoate(FP^-)and cetyltrimethyl ammonium chlo...The average aggregate number(N)of electrostatically stabilized aggregate(ESAg)composed of oppositely-charged long-chain molecules,i.e., sodium ω-[α-(nathphyl)ethoxyl]undecanoate(FP^-)and cetyltrimethyl ammonium chloride(CTAC),in aqueous solution at 25℃ has been measured to be 11 to 16 in the CTAC-concentration range of 11×10^(-5) M to 30×10^(-5) M at a fixed FP- concentration of 1.0×10^(-5)M by the photon counting method.展开更多
文摘We present a new analytical model for electrostatically actuated microbeams to explore the size effect by using the modified couple stress theory and the minimum total potential energy principle. A material length scale parameter is introduced to represent the size-dependent characteristics of microbeams. This model also accounts for the nonlinearities associated with the mid-plane stretching force and the electrostatical force. Numerical analysis for microbeams with clamped-clamped and cantilevered conditions has been performed. It is found that the intensity of size effect is closely associated with the thickness of the microbeam,and smaller beam thickness displays stronger size effect and hence yields smaller deffection and larger pull-in voltage. When the beam thickness is comparable to the material length scale parameter,the size effect is significant and the present theoretical model including the material length scale parameter is adequate for predicting the static behavior of microbeam-based MEMS.
基金supported by the Shandong Province Scientific Research Fund Project of Binzhou University under Grant No. BZXYLG200704
文摘Non-spherical of rotor was described with solution method. Electrostatically suspended gyroscope＇s hollow spherical rotor＇s structure was presented. The simulative analysis of static deformation, dynamic deformation and synthesize deformation of rotor under different working conditions using the finite element software were carried out. Its deformation law and volume were obtained. The structural parameters of the rotor were optimized. The value of pressure required when the rotor was machined was calculated. The analysis has important theoretical reference value to the design for hollow spherical rotor in electrostatically suspended gyroscope.
基金Project supported by the National Natural Science Foundation of China （No. 20272078） and Shanghai Municipal Science and Technology Commission （No. 03JC14083）.
文摘The aggregation behavior of a cationic fluorescence probe 10-（4,7,10,13,16-pentaoxa- 1-azacyclooctadecylmethyl）anthracen-9-ylmethyl dodecanoate （1） was observed and studied by a fluorescence methodology in acidic and neutral conditions. By using the Py scale, differences between simple aggregates and micelles have been discussed. The stability of simple aggregates was discussed in terms of hydrophobic interaction and electrostatic repulsion. The absence of excimer emission of the anthrancene moiety of probe 1 in neutral condition was attributed to the photoinduced electron transfer mechanism instead of photodimerization.
基金the National Natural ScienceFoundation of China(No.59982002) Foundation of National Key Lab.of Advanced Metal Materials.
文摘The electrostatically self-assembly method is getting strategically important to prepare multilayer thin films. With careful choice of component materials, this method should allow for the preparation of multilayer thin films with a variety of excellent technological properties. Ti02/PSS multilayer thin films with ordered structure were prepared by electrostatic self-assembly method. UV-Vis-NIR spectrophotometer, X-ray photoelectron spectroscopy (XPS), and atom force microscopy (AFM) were used to characterize the structure and performance of the multilayer films. Because electrostatically self-assembly method allows molecular-level control over the film composition and thickness, this paper studied the responding depth of photocatalytic activity of Ti02 self-assembled films in detail.
基金Sponsored by the Pre-weapons Research Fund(Grant No.9140A09020706JW0314)New Teacher Research Fund for the Doctoral Program of HigherEducation of China(Grant No.200802481026)
文摘A micromachined electrostatically suspended gyroscope(MESG)based on UV-LIGA microfabrication process was introduced.By close-loop control,the suspended rotor is kept in null position and through the torque rebalance loop,in which the output control voltages reflects the input angular velocity,a dual-axis input angular velocity can be measured simultaneously.First,the system model of MESG was established by dynamic analysis based on the torque analysis.Then,the rebalance loop under ideal condition is designed using modern control technique.The performance of the designed decoupling rebalance loop was compared with that of conventional proportional integral differential(PID)rebalance loop combined with the compensation loop.In order to realize the decoupling of the output voltages,a compensated decoupling matrix and its difference equation were presented and realized by a digital decoupling method employing digital signal processor(DSP).It was confirmed that the controller could realize the complete decoupling and improve the performance of the gyroscope,which includes merits of fast response speed,low overshoot and good dynamic performance,as the simulation results shown.At last,the circuit and digital realization scheme were given.
文摘For the electrostatically suspended gyro （ESG） with solid rotor, because the equatorial photoelectric sensor won＇t sense the equatorial marking line and output the correct damping control information when the nutation angle is small, the active damping with equatorial marking line will bring considerable error. The passive damping method by applying strong DC magnetic field requires too much time. So an active damping method by longitude marking lines is proposed to fulfill the fine damping for solid ESG rotor. The shape of rotor marking lines and the principle of fine damping are introduced. The simulation results prove that this fine damping method can effectively solve the problem of damping error introduced by active damping with equatorial marking line. The estimating resuits for damping time indicate that the fine damping time is less than 10 percent of passive damping time.
文摘 The coaggregating behavior of the cationic kinetic probe P16;with different types of surfactants are in complete agreement with predictions based on the newly proposed ESAg concept.
基金National Defense Pre-research Foundation of China(No.51409060104JW0307)
文摘A research on the electrostatic torques in the electrostatically suspended gyroscope (ESG) that uses the mass-unbalance modulation (MUM) scheme (MUM-ESG) to sense the direction of the rotor's spinning axis is presented here. Spherical harmonic functions are used to describe the asphericity of the rotor and the electrodes. Rotational matrix theory in quantum mechanics is utilized to transform the description of the rotor's asphericity from the rotor-fixed frame into the cavity-fixed frame. And the principle of the virtual displacement is applied to find out the electrostatic torques acting on the rotor. Analytical expressions of the electrostatic torques indicate that there are only three kinds of factors need to be considered when looking for the electrostatic torques in the MUM-ESG. The factors are the asphericity of the rotor, the eccentric rotation of the rotor, and the coupling between the rotor's translational displacement and asphericity. An intuitionistic explanation for the electrostatic torque that comes of the rotor's eccentric rotation is presented also. The effects of these conclusions should be tested and verified in the future experiments and applications.
文摘Hydr hobie一lipophilic interactions(HLI)will start to bri about the formationof simple aggregates(Ag,s)and eoa egates(CoAg,s)from neutral organie moleeuleswhich possess at least onefl ble chain with more than seven eHZ grou ,1,2 at theeritieala egate eoncentration
文摘The average aggregate number(N)of electrostatically stabilized aggregate(ESAg)composed of oppositely-charged long-chain molecules,i.e., sodium ω-[α-(nathphyl)ethoxyl]undecanoate(FP^-)and cetyltrimethyl ammonium chloride(CTAC),in aqueous solution at 25℃ has been measured to be 11 to 16 in the CTAC-concentration range of 11×10^(-5) M to 30×10^(-5) M at a fixed FP- concentration of 1.0×10^(-5)M by the photon counting method.
