Preparation and Electrochemical Characteristics of Three-dimensional Manganese Oxide Micro-supercapacitor Electrode

In order to increase the electrode surface area and enhance the charge storage capacity, we study the micro electro mechanical system technology to fabricate three-dimensional high aspect ratio micro-electrode structure based on glass. The anodic constant potential method is employed to deposit manganese oxide as electroactive substances on the micro-electrode surface. Cyclic voltammetry and constant current charge-discharge method are both used to prepare electrode electrochemical performance testing, with a two-dimensional electrode without structure for comparison. Experimental results show that three-dimensional elec- trode structure can effectively enhance the charge storage capacity. At 1.0 mA/cm2 charge- discharge density, the three-dimensional electrode shows a capacitance of 17.88 mF/cm2, seven times higher than the two-dimensional electrode.

NEW ROD-SHAPED ULTRASONIC MICROMOTOR AND ITS DRIVING PRINCIPLE

A new rod-shaped traveling wave ultrasonic micromotor is developed. In the micromotor, five pieces of piezoelectric ceramics clamped by two metal cylinders are used as its stator. The driving principle of the rodshaped ultrasonic motor is simulated. The stator structure and the position to lay these piezoelectric ceramics are calculated to improve the electro mechanical conversion efficiency. A flexible rotor is designed to reduce the radial slip between the stator and the rotor, and to improve the motor efficiency. The prototype motor and its micror driver are tested. The motor is 9 mm in out-diameter, 15 mm in length and 3.2 g in weight. When the motor operates with the first bending frequency （72 kHz） of the stator, its maximal rotational speed and the torque reach 520 r/rain and 4.5 mN · m. Results show that the motor has good stability. The speed fluctuation is controlled within 3% by the frequency automatic tracking technique.

Real-Time, Automatic and Wireless Bridge Monitoring System Based on MEMS Technology

Currently, the monitoring of bridges in China heavily relies on manual operation, which has several major problems. It generally takes a very long time to complete an inspection process on bridges. The manual data is sometimes unreliable or even wrong in the case of careless operation. The inspection activity itself is dangerous for inspectors, e.g., bridges are located in the sea or river. Some semi-automatic monitoring methods are recently employed, but they are either very expensive or do not work properly. Therefore, the traditional bridge monitoring process becomes an increasing challenge for bridge operators. In this paper, a real-time and automatic bridge monitoring system is presented to meet the bridge monitoring needs, and MEMS （Micro Electro Mechanical Systems） are the key building block in this system. By using the MEMS-based sensors, it is much more efficient and accurate in monitoring bridges with the measurement of inclination, acceleration, displacement, moisture, temperature, stress and other data.

运用研磨和化学机械抛光技术制备高品质的石英薄膜

石英薄膜的质量是决定各种石英基底的微纳器件品质高低的关键所在。阐述如何运用研磨和化学机械抛光CMP(Chemical&Mechanical Polishing)技术获得高品质石英薄膜的方法。由于石英属于高硬度材料,选用金刚石研磨液和球墨铸铁研磨盘对石英衬底进行研磨,以获得较高的研磨速率和较好的研磨后的表面粗糙度。在石英CMP中,采用特殊的"两步抛"工艺,对衬底进行抛光。第一步粗抛抛光液采用金刚石颗粒直径为0.3μm的研磨液与SiO2颗粒直径为50 nm的抛光液相混合,第二步精抛只采用SiO2的抛光液。实验结果表明,采用上述技术,可以获得高品质的石英薄膜,厚度为(25.1±3.2)μm,表面粗糙度约为0.89 nm(RMS)。

Robust fault detection filter and its application in MEMS-based INS/GPS

Since any disturbance and fault may lead to significant performance degradation in practical dynamical systems,it is essential for a system to be robust to disturbances but sensitive to faults.For this purpose,this paper proposes a robust fault-detection filter for linear discrete time-varying systems.The algorithm uses H∞ estimator to minimize the worst possible amplification from disturbances to estimate errors,and H_ index to maximize the minimum effect of faults on the residual output of the filter.This approach is applied to the MEMS-based INS/GPS.And simulation results show that the new algorithm can reduce the effect of unknown disturbances and has a high sensitivity to faults.

Preparation and characterization of three-dimensional micro-electrode for micro-supercapacitor based on inductively coupled plasma reactive etching technology

The capacity of supercapacitor charge storage depends on the size of the electrode surface area and the active material on the electrodes.To enhance the charge storage capacity with a reduced volume,silicon is used as the electrode material,and three-dimensional electrode structure is prepared to increase the electrode surface area on the footprint area by inductively coupled plasma reactive etching(ICP) techniques.The anodic constant current deposition method is employed to deposit manganese oxide on the electrode surface as the electroactive material.For comparison,samples without slot are prepared with a two-dimensional electrode.Scanning Electron Microscopy(SEM) and Energy Dispersive Spectroscopy(EDS) are used to characterize the surface morphology of the electrode structure and the deposited electroactive material.Electrochemical properties of the electrode are characterized by the cyclic voltammetry(CV) and the constant current charge-discharge method.Experimental results show that our approach can effectively increase the electrode surface area with more electroactive substances,and hence can increase storage capacity of the micro-supercapacitor.

Noise estimation and filtering method of MEMS gyroscope based on EMMAP

Aiming at the problems of low measurement accuracy,uncertainty and nonlinearity of random noise of the micro electro mechanical system(MEMS)gyroscope,a gyroscope noise estimation and filtering method is proposed,which combines expectation maximum(EM)with maximum a posterior(MAP)to form an adpative unscented Kalman filter(UKF),called EMMAP-UKF.According to the MAP estimation principle,a suboptimal unbiased MAP noise statistical estimation model is constructed.Then,EM algorithm is introduced to transform the noise estimation problem into the mathematical expectation maximization problem,which can dynamically adjust the variance of the observed noise.Finally,the estimation and filtering of gyroscope random drift error can be realized.The performance of the gyro noise filtering method is evaluated by Allan variance,and the effectiveness of the method is verified by hardware-in-the-loop simulation.

Integration of Strain Sensors on Additively Manufactured Implantable Devices

The development of personalized healthcare is rapidly growing thanks to the support of low-power electronics,advanced fabrication processes and secured data transmission protocols.Long-acting drug delivery systems able to sustain the release of therapeutics in a controllable manner can provide several advantages in the treatment of chronic diseases.Various systems under development control drug release from an implantable reservoir via concentration driven diffusion through nanofluidic membranes.Given the high drug concentration in the reservoir,an inward osmotic fluid transport occurs across the membrane,which counters the outward diffusion of drugs.The resulting osmotic pressure buildup may be sufficient to cause the failure of implants with associated risks to patients.Confidently assessing the osmotic pressure buildup requires testing in vivo.Here,using metal and polymer AM(additive manufacturing)processes,we designed and developed implantable drug reservoirs with embedded strain sensors to directly measure the osmotic pressure in drug delivery implants in vitro and in vivo.

Study on Energy Stored in Thin Layers of MEMS Ultrasonic Resonance Separator

The particles suspending in liquid suffer acoustical radiation force from ultrasonic field. The force may cause particles movement and has special advantage to separate particles from liquid in Micro Electro Mechanical Systems （MEMS）. It is important to improve the energy stored in liquid layer so as to increase separation ability for decreasing drive demand in MEMS. Resonance may hugely increase the magnitude and generally be employed in micro separator. The summits of admittance spectrum show the resonance frequencies. It may come from resonance in one layer or multi layers in micro separator. This paper studies the difference of energy stored in layers at each rein frequency. It provides the way to select the most effect separation frequency other than admittance spectrum.

RF MEMS Based Reconfigurable Rectangular Slotted Self Similar Antenna

Wireless communication systems which require flexibility and reconfigurability in antenna systems faces main problems like antenna performance, size, weight and cost. A wide band Frequency Reconfigurable Rectangular Slotted Self Similar Antenna has been proposed in this paper. The rectangular slotted patch is repeated for two iterations at different scales and is separated by means of Radio Frequency Micro Electro Mechanical Systems (RF MEMS) switches in order to provide reconfigurability. The antenna can operate in three frequency bandsi.e. K-band, Ku-band and Ka-band by altering the states of RF MEMS switches. To avoid fringing effects and to improve antenna performance, quarter wavelength (λ/4) spacing is required between the antenna and the ground plane. However, a Reconfigurable Antenna requires different λ/4 spacing which is difficult to achieve using a common ground plane. So the Frequency Reconfigurable antenna is integrated with high impedance surface (HIS) like Electronic Band Gap (EBG) structures to suppress standing waves and surface waves with a unified profile thickness of 1.75 mm. The overall dimension of the proposed antenna along with RF MEMS Switch, feed element and HIS is about 8 mm × 8 mm × 1.75 mm. The simulated results of the proposed antenna reveal enhancement in antennas performance like Voltage Standing Wave Ratio (VSWR), Front to Back Ratio (FBR) and bandwidth when it is placed over HIS EBG. Also the radiation patterns of the proposed antenna when placed over EBG shows the suppression of side lobe and backward radiation.

基于MEMS加速度计的强振动记录黑匣子的设计

设计基于MEMS加速度传感器的一种强震记录黑匣子,采用SOC系列C8051F005型单片机对MEMS加速度传感器的输出信号进行A/D转换,记录该设备安装点位所经受的强振加速度值,并通过LCD16032显示一分钟内的振动加速度峰值。该系统具有体积小、安装与操作方便、免维护等特性。

Modeling and Simulation of MOEMS Gyroscope Based on TE-TM Mode Converter

A novel structure design of micro optic electro mechanical system（MOEMS）gyroscope is presented in this paper.The structure combining surface acoustic wave（SAW）sensor,optical waveguide diffractive component,electro-optical modulator etc.is integrated on a LiNbO3 substrate as the gyroscope for sensing rotating angular velocity,and an optical readout device is added on the traditional SAW typed TE-TM mode converter as the detecting device.The principles of the MOEMS are discussed in the paper,and simulation result shows that there would be apparent advantages of higher precision and stronger anti-vibration capacity.

From MEMS to NEMS： Smart Chips with Senses and Muscles

The last half-century was transformed by the electronic revolution that essentially reproduced the human brain and its computing capacity on a chip. But over time, scientists have realized that something was missing to give life, so to speak, to the small chip with a brain： One needed to awaken its senses and develop its muscles! This challenge was solved through MEMS （micro electro mechanical systems）. Indeed, MEMS today are equipped with the sense of sight, smell, hearing, taste and touch through microsensors. They are also capable of physical exertion through small muscles called microactuators. These new capabilities open wide fields of imagination and important specific applications.

Application of Novel Rotation Angular Model for 3D Mouse System Based on MEMS Accelerometers

A new scheme is proposed to model 3D angular motion of a revolving regular object with miniature, low-cost micro electro mechanical systems(MEMS) accelerometers(instead of gyroscope),which is employed in 3D mouse system.To sense 3D angular motion,the static property of MEMS accelerometer,sensitive to gravity acceleration,is exploited.With the three outputs of configured accelerometers,the proposed model is implemented to get the rotary motion of the rigid object.In order to validate the effectiveness of the proposed model,an input device is developed with the configuration of the scheme.Experimental results show that a simulated 3D cube can accurately track the rotation of the input device.The result indicates the feasibility and effectiveness of the proposed model in the 3D mouse system.

Computer Aided Modeling for a Miniature Silicon-on-Insulator MEMS Piezoresistive Pressure Sensor

The silicon-on-insulator diaphragm structure is a combined structure of the silicon dioxide and silicon layer. This work presents a new method to estimate the deflection response of silicon with that of a silicon-on-insulator （SOI） diaphragm structure, based on the burst pressure design approach. It also evaluates the output voltage of the diaphragm under two different conditions, flipped and un-flipped. The new modified analytical model developed and presented in this paper for describing the load deflection of SOI diaphragm is able to predict the deflection accurately when compared with the results obtained by finite element analysis CoventorWare~.