Highly sensitive digital optical sensor with large measurement range based on the dual-microring resonator with waveguide-coupled feedback

We propose a novel high-performance digital optical sensor based on the Mach-Zehnder interferential effect and the dual-microring resonators with the waveguide-coupled feedback. The simulation results show that the sensitivity of the sensor can be orders of magnitude higher than that of aconventional sensor, and high quality factor is not critical in it. Moreover, by optimizing the length of the feedback waveguide to be equal to the perimeter of the ring, the measurement range of the proposed sensor is twice as much as that of the conventional sensor in the weak coupling case.

Theoretical and experimental assessment of a novel method to establish the complete measurement range of the calorimeter and its limit of detection and quantification

For determining the accuracy of a calorimeter over the instrument’s entire measuring range,a novel method has been established.For this new approach,(a)benzoic acid(C_(6)H_(5)CO_(2)H) as a certified reference material(CRM),(b)SiO_(2) and(c)a mixture of CRM benzoic acid and SiO_(2) have been used.To illustrate the essential difference between 1)the novel analytical method for control of the entire measurement range and 2)the calorimeter calibration,both applications of benzoic acid(BA)have been demonstrated.An experimental result showed that BA was successfully used to check the whole calorimeter measurement range.The results also showed that the same new method was successfully applied to determine the limit of detection and quantification.A new instrument testing process and a new measurement technique have thus been established.In this way,the cost of using CRM to control the accuracy of measuring the entire measuring range of the calorimeter,as shown in this paper,is minimized.The requirements of the ISO/IEC 17025:2017 standard are satisfied.ISO/IEC 17025:2017,together with ISO 9001:2015(quality management systems),ISO 14001:2015(relate to environmental protection)and ISO45001:2018(occupational safety),constitute an integrated quality system by which a testing laboratory may also accredit.

MLSI-RT: memorize LOS range measurements identified residual test location algorithm and performance analysis

The dominant error source of mobile terminal location in wireless sensor networks （WSNs） is the non-line-of-sight （NLOS） propagation error. Among the algorithms proposed to mitigate the influence of NLOS propagation error, residual test （RT） is an efficient one, however with high computational complexity （CC）. An improved algorithm that memorizes the light of sight （LOS） range measurements （RMs） identified memorize LOS range measurements identified residual test （MLSI-RT） is presented in this paper to address this problem. The MLSI-RT is based on the assumption that when all RMs are from LOS propagations, the normalized residual follows the central Chi-Square distribution while for NLOS cases it is non-central. This study can reduce the CC by more than 90%.

Tracking method based on separation and combination of the measurements for radar and IR fusion system

A new distributed fusion method of radar/infrared （IR） tracking system based on separation and combination of the measurements is proposed by analyzing the influence of rate measurement. The rate information separated from the radar measurements together with measurements of IR form a pseudo vector of IR, and the corresponding filter is designed. The results indicate that the method not only makes a great improvement to the local tracker＇s performance, but also improves the global tracking precision efficiently.

Measurement of Refractive Index Ranging from 1.42847 to 2.48272 at 1064 nm Using a Quasi-Common-Path Laser Feedback System

Wavelength 1064 nm is one of the most widely used laser wavelengths in industries and science. The high-precision measurement of the refractive index of optical materials at 1064 nm is significant for improving the optical design. We study the direct measurement of refractive index at 1064nm of lasers, including cMcium fluoride （CaF2）, fused silica and zinc selenide （ZnSe）, whose refractive indices cover a large range from 1.42847 to 2.48272. The measurement system is built based on the quasi-common-path Nd：YAG laser feedback interferometry. The thickness can be measured simultaneously with the refractive index. The results demonstrate that the system has absolute uncertainties of ~10-5 and ~10-4 mm in refractive index and thickness measurement, respectively.

Multi-parameter identification of gratings measurement by Experimental Ray Tracing

A simple method for measuring grating groove density as well as its position and orientation is proposed based on the idea of ERT(Experimental Ray Tracing).Conventional methods only measure grating groove density with accuracy limited by its rotary stage and goniometer.The method proposed in the paper utilizes linear guides which could be calibrated to much higher accuracy.It is applicable to gratings of arbitrary surface profile or mosaic of a group of various gratings.Various measurement error sources are simulated by the Monte Carlo method and the results show high accuracy capability of grating parameters identification.A verification testing is performed.The accuracy dependency on main configuration parameters is evaluated.A method to expand measurement range by double wavelength is also discussed.

Method of Predicting Water Content in Crude Oil Based on Measuring Range Automatic Switching

Water content in output crude oil is hard to measure precisely because of wide range of dielectric coefficient of crude oil caused by injected dehydrating and demulsifying agents.The method to reduce measurement error of water content in crude oil proposed in this paper is based on switching measuring ranges of on-line water content analyzer automatically.Measuring precision on data collected from oil field and analyzed by in-field operators can be impressively improved by using back propogation （BP） neural network to predict water content in output crude oil.Application results show that the difficulty in accurately measuring water-oil content ratio can be solved effectively through this combination of on-line measuring range automatic switching and real time prediction,as this method has been tested repeatedly on-site in oil fields with satisfactory prediction results.

Combining Cubic Spline Interpolation and Fast Fourier Transform to Extend Measuring Range of Reflectometry

The reflectometry is a common method used to measure the thickness of thin films. Using a conventional method,its measurable range is limited due to the low resolution of the current spectrometer embedded in the reflectometer.We present a simple method, using cubic spline interpolation to resample the spectrum with a high resolution,to extend the measurable transparent film thickness. A large measuring range up to 385 m in optical thickness is achieved with the commonly used system. The numerical calculation and experimental results demonstrate that using the FFT method combined with cubic spline interpolation resampling in reflectrometry, a simple,easy-to-operate, economic measuring system can be achieved with high measuring accuracy and replicability.

Wide measurement range and high sensitivity spongy MWCNT/polydimethylsiloxane pressure sensor based on a single-electrode enhanced triboelectric nanogenerator

Flexible pressure sensors have broad application prospects,such as human motion monitoring and personalized recognition.However,their applicability is limited by complex structures,low output performance,low sensitivity,and narrow measurement range.In this study,we report a single-electrode spongy triboelectric sensor(SSTS)mainly composed of spongy composite multi-walled carbon nanotubes/polydimethylsiloxane(MWCNT/PDMS)film and conductive fabric,which can simultaneously generate contact electrification and electrostatic induction coupling in a single-electrode contact-separation mode.The SSTS combines the triboelectric effect,properties of doping material,and spongy porous structure(soft sugar as a sacrificial template).An SSTS with an MWCNT content of 10 wt%and a porosity of 64%exhibits high sensitivity,a wide measurement range,and excellent linearity.It also displays two sensitivity regions(slopes):1.324 V/kPa from 1.5 to 28 kPa in the low-pressure range and 0.096 V/kPa from 28 to 316.5 kPa in the high-pressure range,with linearities of 0.980 and 0.979,respectively.Furthermore,the SSTS delivers a high-performance output and high stability,thus enhancing the monitoring of hand pressure changes,human movement,personalized spatial recognition,and other detection tasks.This new strategy for human motion monitoring shows great potential in the healthcare fields,sports rehabilitation,and human-computer interactions.

Recent Development of Dielectric Elastomer Transducers and Potential Applications

Power generation using dielectric elastomer transducers is cheap, light, stackable, easy to install, and highly efficient. Also, since the dielectric elastomer transducer is an actuator developed into an artificial muscle, if the DE motor is further developed, it might be possibly be able to drive a vehicle. Efficient robot driving, various industrial machines and the use of dielectric elastomer sensors to optimize the driving may also help solve the above problems from the perspective of eco-driving. This paper describes the latest level of development of dielectric elastomers, their main problems and solutions to these problems, and their potential applications. The possibilities and concrete plans for building local global smart cities (including local generation power for local consumption), efficient transportation, and environmental monitoring systems utilizing dielectric elastomers are also discussed.

A survey on sensor localization

Localization is one of the fundamental problems in wireless sensor networks （WSNs）, since locations of the sensor nodes are critical to both network operations and most application level tasks. Although the GPS based localization schemes can be used to determine node locations within a few meters, the cost of GPS devices and non-availability of GPS signals in confined environments prevent their use in large scale sensor networks. There exists an extensive body of research that aims at obtaining locations as well as spatial relations of nodes in WSNs without requiring specialized hardware and/or employing only a limited number of anchors that are aware of their own locations. In this paper, we present a comprehensive survey on sensor localization in WSNs covering motivations, problem formulations, solution approaches and performance summary. Future research issues will also be discussed.

Photonic-assisted approach for instantaneous microwave frequency measurement with tunable range by using Mach-Zehnder interferometers

A novel photonic-assisted approach to microwave frequency measurement is proposed and experimentally demonstrated. The proposed scheme is based on the frequency-to-power mapping with different transmis- sion responses. A polarizer is used in one output branch of a phase modulator to simultaneously implement phase modulation and intensity modulation. Owing to the complementary nature of the transmission re- sponses and the Mach-Zehnder interferometers （MZIs）, this scheme theoretically provides high resolution and tunable measurement range. The measurement errors in the experimental results can be kept within 0.2 GHz over a freauencv ranee from 0.1 to 5.3 GHz.

Deep Sea AUV Navigation Using Multiple Acoustic Beacons

Navigation is a critical requirement for the operation of Autonomous Underwater Vehicles（AUVs）.To estimate the vehicle position,we present an algorithm using an extended Kalman filter（EKF） to integrate dead-reckoning position with acoustic ranges from multiple beacons pre-deployed in the operating environment.Owing to high latency,variable sound speed multipath transmissions and unreliability in acoustic measurements,outlier recognition techniques are proposed as well.The navigation algorithm has been tested by the recorded data of deep sea AUV during field operations in a variety of environments.Our results show the improved performance over prior techniques based on position computation.

A Range Adjusted Measure of Super-Efficiency in Integer-Valued Data Envelopment Analysis with Undesirable Outputs

DEA(data envelopment analysis) models can be divided into two groups: Radial DEA and non-radial DEA, and the latter has higher discriminatory power than the former. The range adjusted measure(RAM) is an effective and widely used non-radial DEA approach. However, to the best of our knowledge, there is no literature on the integer-valued super-efficiency RAM-DEA model,especially when undesirable outputs are included. We first propose an integer-valued RAM-DEA mode with undesirable outputs and then extend this model to an integer-valued super-efficiency RAM-DEA model with undesirable outputs. Compared with other DEA models, the two novel models have many advantages: 1) They are non-oriented and non-radial DEA models, which enable decision makers to simultaneously and non-proportionally improve inputs and outputs;2) They can handle integer-valued variables and undesirable outputs, so the results obtained are more reliable;3) The results can be easily obtained as it is based on linear programming;4) The integer-valued super-efficiency RAM-DEA model with undesirable outputs can be used to accurately rank efficient DMUs. The proposed models are applied to evaluate the efficiency of China’s regional transportation systems(RTSs) considering the number of transport accidents(an undesirable output). The results help decision makers improve the performance of inefficient RTSs and analyze the strengths of efficient RTSs.

Integrated Computer Aided Shoe-Making System

Shoemaking is one of the areas where CAD/CAM application is rapidly increasing.This paper introduces an integrated computer aided shoemaking system including human foot measuring,last (wooden model)measuring,last CAD/CAM and pattern CAD/CAM.The project was supported by the 7th national economical 5 year plan.High technologies,suh as digital image processing,pattern rcognition,advanced geometrical modeling and a series of sophisticated equipments and devices are ap- plied in this integrated system.Parts of the system have become commercial products.

Feedforward Control for Wind Turbine Load Reduction with Pseudo-LIDAR Measurement

A gain-scheduled feedforward controller, based on pseudo-LIDAR （light detection and ranging） wind speed measurement, is designed to augment the baseline feedback controller for wind turbine＇s load reduction in above rated operation. The pseudo-LIDAR measurement data are generated from a commercial software- Bladed using a designed sampling strategy. The nonlinear wind turbine model has been simplified and linearised at a set of equilibrium operating points. The feedforward controller is firstly developed based on a linearised model at an above rated wind speed, and then expanded to the full above rated operational envelope by employing gain scheduling strategy. The combined feedforward and baseline feedback control is simulated on a 5MW industrial wind turbine model. Simulation studies demonstrate that the proposed control strategy can improve the rotor and tower load reduction performance for large wind turbines.

Nested microring resonator with a doubled free spectral range for sensing application

The microring resonator has received increas- ing attention in the optical sensing application because of its micro-size, optical property, and high sensitivity. An additional waveguide is commonly used to change the output spectra in the early research on microring resonators. In this study, we proposed a nested microring resonator that doubles the free spectral range （FSR） compared with the conventional single microring. This structure improved the sensing property as the FSR in the filter output spectra could be considered as a measurement range in the microring sensor. Moreover, the parameters including the coupling coefficient of the three coupling sections, length of the U-bend waveguide, and effective index of a waveguide were tested and carefully selected to optimize the sensing properties. The relationship between these parameters and the output spectra was demonstrated. With linear sensitivity, the structure has a good potential in sensing application.

Porous fiber paper and 3D patterned electrodes composed high-sensitivity flexible piezoresistive sensor for physiological signal monitoring

The research on flexible pressure sensors has drawn widespread attention in recent years,especially in the fields of health care and intelligent robots.In practical applications,the sensitivity of sensors directly affects the precision and integrity of weak pressure signals.Here,a pressure sensor with high sensitivity and a wide measurement range composed of porous fiber paper and 3D patterned electrodes is proposed.Multi-walled carbon nanotubes with excellent conductivity were evenly sprayed on the fiber paper to form the natural spatial conducting networks,while the copper-deposited polydimethylsiloxane films with micropyramids array were used as electrodes and flexible substrates.Increased conducting paths between electrodes and fibers can be obtained when high-density micro-pyramids fall into the porous structures of the fiber paper under external pressure,thereby promoting the pressure sensor to show an ultra-high sensitivity of 17.65 kPa^(-1)in the pressure range of 0–2 kPa,16 times that of the device without patterned electrodes.Besides,the sensor retains a high sensitivity of 2.06 kPa^(-1)in an ultra-wide measurement range of 150 kPa.Moreover,the sensor can detect various physiological signals,including pulse and voice,while attached to the human skin.This work provides a novel strategy to significantly improve the sensitivity and measurement range of flexible pressure sensors,as well as demonstrates attractive applications in physiological signal monitoring.

Fabrication of a Flexible Electric Skin Using a Bionic Cell and Study of Its Sensing Ability

Imitating the structure and function of the Pacinian corpuscle in the human body,a Bionic Cell(BC)with a liquid core was designed and made with polyvinylidene fluoride(PVDF),and an Electronic Skin(ES)sensor was successfully obtained by embedding the BCs into silicone rubber.The passive sensing ability of the ES for surface vibration pressure was measured.The results showed that the ES could detect waveform,frequency,amplitude and other parameters of the surface,and it exhibited not only a high sensitivity of 0.46563 fc/Pa,but also a large pressure measurement range of 0.6 Pa–6014 Pa.A falling real object impact experiment was carried out,and the results indicated that the ES output charge was linearly related to the falling height of the object and logarithmically related to the mass of the object.Then,a crawling insect experiment and human pulse experiment were performed to study the perception ability of the ES to irregular pressure.Due to its special structure,simple fabrication process,and high sensitivity wide measurement range,the ES fabricated in this paper is expected to be used as robot skin with tactile perception ability in the near future.