A portable and high-resolution optomechanical accelerometer employing a deformable grating-based micro-electro-mechanical system (MEMS) interferometer is presented in this Letter. The movable reflective mirror of realized by low-frequency vertical sensing structure with three-dimensional (3D)-spring construction, which, to the best our knowledge, first proposed fabricated work. All components sensor are packaged metal case compact size 4 cm×6 cm×3.15 cm. micrometer-scale springs permit...

Conventional cross-correlation is commonly used in the estimation of spectral shift for optical frequency-domain reflectometry (OFDR) based distributed sensing. However, potential errors cases relatively large shifts have severely limited sensing dynamic range. We report a modified longest common substring algorithm that exploits two-dimensional image processing more accurate estimation. Theoretical study conventional conducted, which reveals quantitatively underlying mechanism emergence...

High-sensitivity accelerometry has historically been employed to explore Earth sciences and advance resource-related industries, such as petroleum exploitation. The devices capable of measurements, however, traditionally involve precise mechanical structures consequent large dimensions. In this article, combined by micromechanical systems grating-assisted interferometry, a closed-loop optical accelerometer with nano-g (ng) sensitivity is developed for microseismic observations. order lower...

Optical sensing techniques are well-known for electromagnetic immunity and thus have been widely considered in high-performance vibration sensors such as accelerometers seismometers. In the progress of miniaturization, however, force feedback control has rarely developed due to associated complexity optical loops. Aiming further explore application interferometry geophysics, a force-rebalanced micro-optics accelerometer is this work. This device operates relying on grating-based MEMS...

A low-carbon economy is the most important requirement to realize high-quality integrated development of Yangtze River Delta. Utilizing following models: a super-efficiency slacks-based measure model, spatio-temporal correlation bivariate LISA spatial econometric and geographically weighted random forest this study measured urban industrial eco-efficiency (IEE) then analyzed its influencing effects on carbon emission in Delta from 2000 2017. The factors included intensity, association type,...

Comprehensive human development is the ultimate goal of achieving a happy life and creating sustainable social development. This study examines 31 provinces in China as research object, constructs an evaluation index system for comprehensive three dimensions (human–nature, human–society, human–human), analyzes spatio-temporal evolution patterns. Barrier regression analyses are used to identify main drivers levels different regions. The results show that: (1) China’s level has been on rise...

Traditional seismometers and gravimeters normally have large volumes entail high manufacturing costs. Aiming at the miniaturization of such geophysical instruments, a portable Micro-electro-mechanical Systems (MEMS) accelerometer applicable to seismic-grade measurements is fabricated characterized in this work. This operating on deformable grating-based MEMS interferometer, where new out-of-plane sensing chip employing double layers 10 μm-thickness spring first proposed. The...

This work presents design, fabrication and experimental demonstration of a high-resolution optical Micro-Electro-Mechanical Systems (MEMS) accelerometer applicable to microseismic observations. device employs deformable grating based interferometer transduce tiny accelerations into variations light intensity. A low-frequency Z-axis-sensitive MEMS sensing structure, which has three-dimensional (3D)-suspension is fabricated serve as the element. The mechanical modules are both assembled...

In distributed fiber-optic sensing based on optical frequency domain reflectometry (OFDR), Doppler shifts due to the changes of disturbances during one sweep period introduce demodulation errors that accumulate along both distance and time, impairing performance. Here, we report dynamic strain using Doppler-shift-immune phase-sensitive OFDR frequency-tracking spectrum-zooming with ultra-weak reflection array. Theoretical study has been carried out introduction mismatch coefficient, unveiling...

In distributed fiber-optic sensing based on optical frequency domain reflectometry (OFDR), Doppler shifts due to the changes of disturbances during one sweep period introduce demodulation errors that accumulate along both distance and time, impairing performance. Here, we report dynamic strain using Doppler-shift-immune phase-sensitive OFDR frequency-tracking spectrum-zooming with an ultra-weak reflection array. A theoretical study has been carried out introduction mismatch coefficient,...

Grating-assisted optical interferometry is advantageous for high integration and electromagnetic immunity thus powerful developing microscale accelerometers with sensitivity. However, the intensity of interferometric signal normally sinusoidal respect to phase difference, resulting in imperfect linearity limited dynamic range. To combat this enhance utility seismic applications, a digital closed-loop detection system force feedback first equipped micro-electromechanical (MEMS) resonance...

The paper expounds the special properties of nanomaterials, introduces melt blown nonwovens and advantages nanomaterials composites, summarizes methods incorporating nanoparticles into webs at home aboard advantages, disadvantages different methods, finally, new method we taking in study result our study. results show that activated carbon is good distributed on meltblown nonwoven particles embedded within fiber.

In this work, the rare-earth element is doped into GEL/P(AA/AM) hydrogels system based on chemical bonding. The stimuli-response, deformation of responding to application direct current electric field, has been first studied using high speed camera and microscope with digital speckle correlation method (DSCM). It was shown that displacement increases increasing field intensity more sensitive then non-doped hydrogels. direction generated along direction, while in hydrogels, formation against...

Bottom dead center repeat precision is the key evaluation standard of high-speed press, it’s an important index to judge production level and technical level. Use model RM-7201 testing apparatus measure bottom press at different conditions, find out laws according test result. These findings may helpful in proving correctness analysis control B.D.C press. Provide practical guidance basis improve structure precision.