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In China, there are nearly 100,000 earth and rock-filled dams, which are essential water conservancy facilities for agricultural irrigation, food security, flood controlling, and power generation and so on. The periodically deformation monitoring for those dams are the key criterion to evaluate their safety. However, traditional surveying technologies such as levelling, total station and GNSS and some inner sensors (like fibers) for continuous real-time monitoring are costly and require large amounts of human resources.In this paper, we evaluate the ability of the currently operating X-band and C-band SAR sensors on dam deformation monitoring and propose a conversion parameter to retrieve the dam consolidation settlement. According to the earth and rock-filled dam post-construction settlement mechanism, a dam settles due to the compaction effect of filling earth in the dam. While in SAR geometry, only the line-of-sight projection of the slope surface deformation is visible along the radar beam. In order to convert the deformation from SAR geometry to real 3D geometry, we proposed a method for converting the dam post-construction deformation from SAR light of sight to vertical direction, based on the geometrical parameters of the dam and the SAR sensor.The experiments by both simulated and real cases in the Gongming reservoir of Shenzhen city in china are utilized to compare the deformation monitoring capability of various SAR sensors with different resolutions and to demonstrate the applicability of deformation conversion method. The simulation results show that the foreshortening of the slope greatly affects the slope deformation retrieval, for the small earth-rock filled dams with axis being parallel to the SAR heading direction, the conversion parameter between two slopes of dam maybe differ than 2~3 times. The real experiments, by both the differential interferogram and time series analysis, based on TSX, CSK and Sentinel-1 data in Shenzhen Gongming reservoir show that the high-resolution data have more precise results. The time series analysis of multi-SAR data from 2017 to 2021 are used to show full processing of the dam post-construction settlement. For the small dam which is nearly 30 meters high and 200 meters long, With the 1~3 meters resolution of TSX and CSK data, we can retrieve the dam settlement from both the cross-section profile and the axis section profile. The Sentinel TOPS data sets with low resolution cannot fully retrieve the dam settlement and the results are underestimated.

Supplemental material, sj-pdf-2-imr-10.1177_03000605221111275 for Changes in plasma IRAK-M in patients with prediabetes and its relationship with related metabolic indexes: a cross-sectional study by Xiaomin Xie, Guirong Bai, Li Zhang, Huili Liu, Dan Qiang and Ling Li in Journal of International Medical Research

The natural evolution of urban forms over time is a key issue in urban morphology. With the rapid development of 7quantitative analytical tools and new urban data, new research potential has emerged. This study attempts to develop an analytical framework for evaluating the urban maturation process. Using street blocks as the analytical unit, this study integrates the spatial design network analysis (sDNA), Spacematrix, Points-of-Interests (POIs), and Open Street Map (OSM) in the geographical information system (GIS) to calculate the urban maturation index in the context of big data. Shanghai, a metropolitan city with a long urbanisation history and a series of new towns, was selected as the case study. The validation of this new index was first achieved by comparing this maturation index between several districts located in the city centre and suburban new towns. Insights in this direction would help generate new urban design guidance for creating vibrant urban places. This study also aimed to introduce new quantitative thinking into the previously qualitative and intuition-based fields of urban morphology and urban design.

Epidermal growth factor (EGF) has various important physiological functions, which it exerts by binding to the epidermal growth factor receptor (EGFR). Reports show that EGF expression is strongly correlated with the occurrence and development of many types of tumour. To date, however, the relationship between EGF/EGFR and the occurrence and development of thyroid carcinoma remains unclear.In the current study, we investigated this phenomenon using human anaplastic thyroid carcinoma cell lines (SUN-80).The results indicated that EGF triggered the EGFR-mediated intracellular signalling pathway, including signal transducers and activators of transcription 1/3/5 (STAT1/3/5) and protein kinase B (AKT) in a time- and dose-dependent manner. In addition, results from EGF-induced EGFR internalization and co-localization analyses showed that clathrin, Rab5/7, and EEA1 play critical roles in the intracellular trafficking of EGF/EGFR. Interestingly, EGF triggered EGFR translocation into the nucleus, while nuclear-localized EGFR affected cell cycle distribution, thereby significantly promoting the ration of S phase. Overall, these findings indicated that nuclear EGFR exerts biological activity and physiological functions, including changing cell cycle, which in turn promotes proliferation and migration of SUN-80 cells.These findings lay a foundation for further explorations seeking to understand the biological effects of the EGF/EGFR system on the occurrence and development of thyroid cancer.

In order to overcome the imbalance of cells in series lithium-ion battery pack, this paper proposes a new switched equalization and its FSM control method. N-MOSFETs and P-MOSFETs are used to build the switch array of the equalization. The Buck-Boost circuit including a super capacitor is used to achieve the energy balance in cells. The equalization strategy based on FSM describes the principle of switched equalization. And paper provides switching conditions in states of FSM. The major losses are also analyzed. Finally, with SIMULINK toolbox, a simulation model including 6 series batteries is built. And the simulation results verify the validity of the switched equalization and its FSM control strategy.

The process of dispensing gel above the silicon chip aimed at protecting chip surface and bonding wire is one of the most critical steps in the production of highly accurate low-pressure sensor modules. Numerous research efforts focused on the influences of dispensing process parameters, configuration and mechanical behavior of cured gel on the performance of sensors, while few concerns were taken on the air bubbles formed in protection gel that adversely influence the sensitivity and zero-drift in full temperature range. In this research, a series of hydrostatic fluid-element based 3D models in consideration of different positions and various diameters of gas bubble were conducted to explore this phenomenon. Results show that the existence of gas bubble brings in an extra load and changes the pressure distribution on the sensing membrane of the chip, which will result in zero-drift and sensitivity variation of packaged sensors. The influence degree is closely correlated with the position and size of gas bubble in protection gel. An experiment was conducted to verify the simulation, the results fit well. Due to the random distribution of bubble it is almost impossible to design signal modulation circuits to compensate for voltage drift in mass production. Therefore, in practical production, the gas bubble should be avoided especially in the region close to the sensing membrane of sensor chip.

An increasing number of technologies for MEMS require large-scale integration of heterogeneous components from a donor substrate to a wide range of surfaces. These routes require the ability to direct the placement of devices or components that are too small, too fragile, and too numerous to economically handle by conventional pick-and-place technologies. Possible solutions therefore include self-assembly and new approaches based on adhesion to elastomeric stamps. We introduce a commercially available PDMS (polydimethylsiloxane) rubber (Sylgard 184, Dow Corning). It can grab micro objects from donor substrate and print them to a variety of substrates without specially designed surface chemistry or separate adhesive layers, such as cured surface or flexible substrate. Based on fracture mechanics, whether the PDMS stamp can pick up the component or not depends on the strain energy release rate and interface toughness. On the other hand, viscoelasticity of PDMS plays an important role in the process of transfer printing. Dynamic Measurment Analysis (DMA) method is a main tool to study viscoelasticity of a variety of materials. As is well-known, polymers tend to show elasticity and viscocity at the same time and PDMS is no exception as a kind of rubber. Through DMA experiment we can observe the relationship between storage modulus, loss modulus, etc. and frequency at which the force is loaded on the material. Further more, we can obtain the material constitutive relation. PDMS is a bi-component rubber, prepolymer and curing agent mixed in varying proportions owning different capabilities, accordingly they have different effects in the process of transfer printing. In this article, we have prepared two different proportions of PDMS to conduct DMA experiment to study their viscoelasticity and their effect on transfer printing. According to what have been mentioned above, adhesion between the PDMS stamp and the components (i.e., Van der waals forces ) depends on strain energy release rate and interface toughness. Therefore, we adopt simulation method to study the relationship between the two different proportions of PDMS and their effect on transfer printing. Different proportions of PDMS have different viscoelastic parameters, so they have different constitutive laws. Through the results obtained from simulation we can obviously observe their different properties. The combination of DMA experiment and simulation helps us to conduct the process of transfer printing successfully. Material possess characteristics of viscoelasticity has complex mechanical behaviors, and making their constitutive relation clear will play a more and more important role in variety of micro processes apart from transfer printing.

Wearable electronics have been fashionable in recent years due to the rapid development of Micro-electromechanical Systems (MEMS) technology. Accelerometer, gyroscope and magnetometer are the most popular MEMS-based sensors, and they are widely available in smartphones, tablets, handheld devices and wearable products. However, they are not robust enough for wearable applications. The magnetometer is easily suffered from perturbation because of magnetic disturbance caused by surrounding hard-iron and soft-iron sources from indoor environments. The gyroscope is limited by various error sources that affect long-term and short-term performance, such as bias instability, scale factor and the angle random walk respectively. In this paper, we analyze the influence of surrounding magnetic disturbance on magnetometer output, and the gyroscope output drifting with time. Then, a method is proposed to rapidly calibrate the magnetometer and eliminate error of gyroscope. The Kalman filter algorithm is used during data fusing. In the final, the experiments are implemented using our proposed method and the results show that the accuracy has improved greatly

Although MEMS (Micro Electro-Mechanical System) pressure sensor has been a considerably mature technology and successfully applied in various fields, Packaging is still a major challenge. For the application in harsh environment such as electrolysis, polarization, particulate contamination, corrosion, stiction and excessive heat dissipation, usually, the oil-filled isolated packaging strategy with a steel corrugated diaphragm would be used. Packaging effects of corrugated diaphragm characteristics and volume expansion of oil on sensor performance were studied by some researchers, while, previous researches simply focused on the corrugated plate or just considered the oil as an elastic material without the coupling effect between them. In this paper, a fluid-solid coupling model with the oil as a compressible fluid being simulated by the hydrostatic fluid element was established. The geometric features of corrugated diaphragm and the compression performance of oil were taken into consideration. The results show that more waves, smaller volume of oil would be preferred, and for a low pressure range, almost several kilopascal, the volume is the dominant factor for given specific oil. In order to verify the accuracy of the simulation method, an experiment was conducted, and a special-designed ceramic cubic can be attached around the pressure chip to decrease the oil volume. The output data of packaged modules were recorded under the temperature range from −40°C to 125°C, The trend of data is in good agreement with the prediction of simulation model. This simulating method can be an excellent tool for the research and development of similar packaged sensor.

Accidental falls are frequent and dangerous events for the elderly population, which can result into serious injury or fracture of bones especially hip bone injury or other joint fractures. There are several methods for detecting falls of elderly, such as camera-based, personal emergency response System (PERS), and wearable sensor-based. However, the camera-based method is limited by instrumented spaces and the PERS is suffer from inability to give an alarm after a fall. The wearable sensor-based fall detection is not limited to instrumented spaces, moreover, it is easily to detect the falls through tracking the kinematic information about the monitored person. In this paper, a wearable Micro-electromechanical Systems (MEMS)-based sensors module is designed for fall detection including one three-axis accelerometer, one three-axis gyroscope and one three-axis magnetometer. However, falls from activities of daily living (ADL) make it difficult to distinguish real falls from certain fall-like activities such as sitting down quickly and jumping. An approach is proposed using attitude angles to reduce false falls through tests of static postures and dynamic transitions. Meanwhile, the proposed method has real-time response and high computation efficiency.

With fast growing application of solar photovoltaic (PV) technology, its reliability is being studied extensively. Note that the photovoltaic inverter is considered as the weakest link of a PV system. This paper, therefore, gives a review on reliability of the grid-connected photovoltaic inverter. The discussion mainly focus on two typical kinds of vulnerable inverter components, i.e., DC-capacitors and insulated gate bipolar transistor switches. The intent of this review is to provide a clear picture of reliability research in photovoltaic inverters. Finally, attempts are made to highlight the direction for future research.

A bi-directional isolated Cuk equalizer for the energy bus-based equalization network is presented in this paper. The battery side is isolated from the bus side by two isolated capacitors. A synchronous approach for Cuk equalizer is used to improve equalization efficiency. The equalization efficiency can achieve above 90% in a wide range of equalization power. The operating principle, steady-state analysis and derivation of synchronous conditions have been made to show the merits of the equalization scheme. The validity of this equalization scheme and synchronous conditions has been verified by experiments.

In this paper, a multi-sensor system in package (SiP) is designed for the safety monitoring of the heavy machinery. The multi-sensor is made up of several parts, including strain gauge array, acceleration sensor, temperature sensor, and a pair of ultrasonic detector and actuator. Strain gauge array in a certain pattern is used to monitor the strain and stress level at some critical positions of the heavy machinery. At the same time, the acceleration sensor is used to examine the status of the vibration and monitors possible events such as impact or shock, providing the needed data for loading monitoring and liability, while the ultrasonic detector/actuator is adapted to detect the crack formed within the parts of the heavy machinery for those easy-to-fail parts. All parts of the system are integrated on a special flexible substrate with micro vias, through which the signal transmission and electrical interconnection among all devices are achieved. Besides, the total system is fixed at the heavy machinery through the flexible substrate, so that a real-time safety monitoring for the important parts of the heavy machinery can be accomplished, even when the heavy machinery is at work. The system is powered by two methods. For the lower power devices like the strain gauges, some materials in the system with the property of piezoelectricity can supply the energy for them, while for the larger ones such as the ultrasonic detectors, wire is needed. Apart from those listed above, wireless transmission devices are also included in the system so that the signal can be sent and received. The system prototype has been made and it is expected that the module will be integrated into the internet of things, a service network good for maintaining and servicing of engineering product systems in the field.

Design and implementation is critically important for micro electro mechanical systems (MEMS) based devices, modules. As a typical instance, modern attitude and heading reference systems (AHRS) generally use Kalman Filter to integrate gyroscopes with some other augmenting sensors, such as accelerometers and magnetometers, so as to provide a long term stable orientation solution. While warpage of printed circuit board (PCB) induced by initial installation error or thermal deflection may result in non-orthogonality and misalignment of MEMS devices, similar to inner inter-axis alignment error of multi-axis MEMS device, consequently output values of MEMS devices are unable to reflect the actual angular velocity, acceleration and magnetic field intensity, etc. These physical quantities obtained in the body frame cannot be transformed into the local level frame exactly, so that the accuracy of attitude and heading reference system cannot be guaranteed during the long time Kalman filtering process. This paper deals with the warpage of a micro AHRS composed of the low-cost inertial and magnetic sensors. Experimental results show that thermal cycling has a significant impact on the accuracy of AHRS. A warpage model of PCB based on thermomechanics is developed. Then the non-orthogonality and misalignment matrices induced by thermal deflection are obtained. A body/local level frame transformation matrix is used to study that mechanical parameters (orthogonalization and alignment parameters) are not independent of temperature and time during operation. The most important concern is that this accumulated error is unbounded in time. We analyze the interactions between MEMS device and its application to system so as to guarantee the accuracy of AHRS. Experiments and simulation results are consistent with what we envisage before.

In this paper, we investigate the influence of warpage on the state estimation of the gyro-free IMU. A configuration-optimized gyro-free IMU is designed for investigation. Four triaxial MEMS accelerometers with specified configuration are used in order to directly determine the magnitude and sign of the angular velocity without integration. An optimized configuration geometry is presented to increase the observability of the body motion since the performance of the gyro-free IMU is affected by the configuration geometry of the distributed accelerometers. An effective unscented Kalman filter (UKF) is applied to estimate the system state. The mechatronic implementation of the distributed accelerometers consists of four triaxial MEMS accelerometers, each mounted on a separate board. The warpage model of the board based on thermal stress is built and developed. The main assumptions of this model are that the material of the board is FR4 which is widely used in Printed Circuit Board (PCB) and accelerometers are all rigid. Temperature is set within operating temperature ranging from −40°C to +85°C. We analyze the board warpage induced by thermal stress at −40°C, room temperature (+25°C) and +85°C. Then the position and sensing direction errors of each accelerometer are obtained from the simulation results respectively. Consequently, the board state is robustly estimated by the applied UKF. The results show that warpage induces errors to state estimation of a gyro-free IMU.

The mechanism of resonant frequency shift of MEMS gyroscope subjected to environment temperature change was investigated comprehensively in this paper, and its computational model was set up based on certain assumptions. Taking the structure of MEMS gyroscope as an example using the finite element method, firstly, the authors derived the simplified M-C-K dynamic model. Then, thermal stress and the thermal deformation of the model were calculated within temperature range from -40°Cto 120°C, and the regions of maximum value of thermal stress and thermal deformation were selected in the regions between anchors and driving spring beams. Finally, the analysis of modes was implemented under varying temperature ranging from -40°C to 120°C, and the relation between resonant frequency shift and temperature change was given at the reference temperature of 20°C. The results showed that the driving resonant frequency decreased while the resonant sensing frequency fluctuated in certain value when the environment temperature increased, which indicated that frequency shift was greatly dependent on thermal stress of the driving spring beams that suspended the driving comb structure.

The process of dispensing gel above the silicon chip aimed at protecting chip surface and bonding wire is one of the most critical steps in the production of highly accurate low-pressure sensor modules. Numerous research efforts focused on the influences of dispensing process parameters, configuration and mechanical behavior of cured gel on the performance of sensors, while few concerns were taken on the air bubbles formed in cured gel induced by inappropriate technology control that adversely influence the zero offset in full temperature range and sensitivity. In this paper, the packaged modules of sensor chip attached on the ceramic substrate were chosen as the subject investigated, a series of hydrostatic fluid-element based 2D models in consideration of different positions and various diameters of air bubbles were conducted to explore this phenomenon. The simulation results showed that the inflation of bubble and elevated air pressure give rise to extra load on the sensing membrane, and this phenomenon becomes more evident as the initial distance between bubble and sensing element becomes shorter and the original diameter becomes larger. Even for the case of smallest diameter and farest distance, the maximum output variation could be 0.5% for a pressure point, this is still unacceptable for the production of high-precision and reliable low pressure sensors. So a vaccumizing process between the dispensing and curing processes could be preferred.

The thermal effect on performance of micromachined hemispherical vibratory gyroscope subjected to environment temperature change was investigated comprehensively in this paper. Firstly, the structure and principle of typical micromachined hemispherical gyroscope were introduced, and its advantages over other micromachined gyroscopes were demonstrated Taking a typical micromachined hemispherical gyroscope as a model, then, the analysis of modes was implemented under varying environment temperature ranging from −40°C to 120°C, and the relation between resonant frequency shift and temperature change was given based on the reference temperature of 20°C. The results showed that all order resonant frequencies decreased when environment temperature increased, and the high order frequency shifted more than the low order frequency. Finally, the reference state was chosen when the micromachined hemispherical gyroscope was driven at the driving resonant frequency and at room temperature of 20°C, and the sensing vibration amplitude presented the angular rate output. The sensing vibration amplitudes were calculated with the angular rate input from 0/s to π/s and environment temperature changing from −40°C to 120°C, and it concluded that temperature change can seriously degrade the angular rate output.

In this paper, simulation model for the response time of micro flow sensor using COMSOL Multiphysics is presented. The detailed structure of the micro flow sensor chip is considered in the simulation model. What's more, the temperature dependencies of physical properties of air are defined to improve the model precision. The model takes into consideration the transient conduction and convection between the sensor structure and fluid region. The effects of mass flow rate, thermistor position, input power and depth of flow channel on the response time of the micro flow sensor are investigated in detail. The effect of air relative humidity on the response time of the micro flow sensor is also studied. The results show the geometry parameters are the main factors that affect the response time.

This paper presents a method to calculate the air damping coefficient and the quality factor value in MEMS gyroscope at different cavity pressures. Taking the structure of MEMS gyroscope as an example, firstly, the authors derived the simplified M-C-K dynamic model. Then, the elements of mass matrix and stiffness matrix were calculated based on certain assumptions, especially the air damping coefficient with the theory of slide-film damping and squeeze-film damping. Finally, with relative elements of mass, damping and stiffness matrix, we obtained the quality factors Qs in the driving direction and the sensing direction at different cavity pressures. The results showed that the quality factors Qs both in the driving direction and the sensing direction increase with the decrease of the cavity pressure, and the quality factor Q in the driving direction is much bigger than that in the sensing direction.