ABSTRACT Microwave heating is a booming technology in the food industry that has gained attention for its outstanding benefits. However, problem of uneven remains persistent challenge practical applications. To solve this problem, study presents novel microwave method improves uniformity by generating rotating electric field. unlike traditional methods, it does not rely on physical rotation. illustrate succinctly, structure with three center‐symmetric coupling slots was designed. The cyclic...

Electrical impedance tomography (EIT) is a promising visualization measurement technique to reconstruct media distribution in region of interest (ROI) through measurements on its boundary. In this paper, two-to-four-terminal mode proposed for two-terminal EIT system take advantage the four-terminal imaging mechanism. Using mode, data are acquired using system, whereas mechanism based mode. To realize mapping formulas from two- and vice versa derived. A novel method decrease ill...

A straight-line-type Sagnac optic fiber acoustic sensing system is proposed in this paper to adopt the application needs of no man’s plateau borderline for monitoring mechanical invasion. The interference loop replaced by a straight-line and 1 × 2 coupler, length shortened close 50%. influences delay on are analyzed theory calculation simulation optimal lengths were decided. experiment was set, wound into titanium alloy cylinder compose element. Experimental results show that has good...

An improved acoustic pick-up is presented to enhance the sensing sensitivity of straight line-type Sagnac fiber optic system. A hollow elastomer cylinder introduced into system, and optical tightly wound around construct pick-up. The theoretical analysis was finished, it showed that will bring in an extra phase change let difference increase almost order. correspondingly. titanium alloy elastic designed manufactured. experiment system built, a sinusoidal signal used as sound source. tests...

An all-fiber temperature sensor employing intentional refractive index modulation is experimentally demonstrated. The consists of four sections polarization maintaining fiber (FPMF) sandwiched between multi-mode (MMF). stress region two fibers (PMFs) aligned and then anti-clockwise rotates one PMF in 10 deg angles while the other keeps still. Finally, discharge proceeds. remaining PMFs are fusion spliced with same method. Then prepared FPMF-MMF structure connected to 3 dB coupler construct a...

This paper proposes a fiber optic Fabry-Perot (F-P) strain sensing system using non-scan correlation demodulation applied to the health monitoring of pressurized water reactor's fuel assembly structures. The structural design and mechanism analysis sensor were carried out, transfer model from sheet gauge was established. After fabrication installation, static tests have been conducted, results indicate that can accurately measure microstrain with sensitivity up 12.6 nm/με at high temperature...

To solve the problem of multiple sound recognition in application Sagnac optical fiber acoustic sensing system, a multi-source synchronous algorithm was proposed, which combined VMD (variational modal decomposition) and MFCC (Mel-frequency cepstral coefficient algorithm) to pre-process photoacoustic signal, uses BP neural network recognize signal. The analysis feature extraction theory signal based on algorithms were presented. system program design completed network. Signal acquisition...

We propose a new Fourier transform spectrometer based on programmable microelectromechanical systems (MEMS) micro-mirror and an improved Michelson interferometer.The principle of the is theoretically analyzed.A signal acquisition unit experimental set-up are designed.The spectrum polychromatic light source obtained at slantwise reflector angle 0.238 • .The analyzed by this system within near infrared.The results show that spectral accuracy less than 3 nm, signal-to-noise ratio (SNR) 18...

小尺寸目标跟踪是视觉跟踪中的难题。该文首先指出了均值移动小尺寸目标跟踪算法中的两个主要问题：算法跟踪中断和丢失跟踪目标。然后，论文给出了相应的解决方法。对传统Parzen窗密度估计法加以改进，并用于对候选目标区域的直方图进行插值处理，较好地解决了算法跟踪中断问题。论文采用Kullback-Leibler距离作为目标模型和候选目标之间的新型相似性度量函数，并推导了其相应的权值和新位置计算公式，提高了算法的跟踪精度。多段视频序列的跟踪实验表明，该文提出的算法可以有效地跟踪小尺寸目标，能够成功跟踪只有612个像素的小目标，跟踪精度也有一定提高。

Abstract Measuring the vibration displacement of fuel pin is crucial for determining level and monitoring condition assembly. A miniaturized sensor based on fiber Fabry–Perot (F–P) was designed fabricated, overall cylindrical dimensions encapsulated F–P were 30 mm × 6.5 mm. Its working principle, characteristics, structure parameters analyzed in detail. Experimental results showed that measurement range displacements up to approximately 1250 μm humid environment. And root mean squared error...

Backscatter noise is a key limiting factor in the performance of resonant fiber optic gyroscopes. To enhance accuracy gyroscopes, gyroscope system based on sideband locking technology proposed. In this scheme, two tunable semiconductor lasers independently provide clockwise and counterclockwise optical paths. An phase-locked loop employed to achieve independent subharmonic phase output lights, with their frequency difference equaling one free spectral range (FSR). By applying sinusoidal...

A new pickup structure was introduced and modified to improve the resolution of linear Sagnac optical fiber acoustic sensing system. The maximum strains corresponding material, diameter, wall thickness, height pickups were analyzed by simulation. An aluminum cylinder with a diameter 110 mm, thickness 3 120 mm chosen as basic pickup. four-groove vertical width 80 horizontal 20 sensitivity experiments showed that average peak-to-peak increased 215.54% 106.806 mV/Pa. improved can be applied in...

Heterodyne dual-frequency laser interference displacement measurement has been widely applied in the precision mechanical systems. A signal modulation circuit with four-phase quadrant-square wave output was proposed to improve sensitivity of detection differential system. front-end photoelectric conversion circuit, mixing waveform and fourway quadrantal square shaping are designed manufactured. testing platform built laboratory test finished. The speed system reach 3<i>m/s</i>, frequency...

Human Activity Recognition (HAR) has attracted much attention due to the application in consumer electronics. To address shortcomings of existing HARs, such as no identification, privacy leakage, battery maintenance, low accuracy, and few recognized activities, we have proposed new bound-RFID HARs. Firstly, devised body RFID skeleton sense human activity by collecting tag response records node, which form dataset suitable for a benchmark. Secondly, propose data standardization solve problem...

Multimodal wireless networks are that offer multiple functionalities realized on the same infrastructure. In this paper, we consider a multimodal network has two modes of operation: communication mode, when is used as traditional network, and surveillance distributed sensor can detect illegal intrusion by detecting changes in propagation environment caused intruder. We address problem consisting nodes: develop multi-sensor model for received signal parameters interest derive detector capable...

ABSTRACT This paper presents a non-scanning Fourier transform spectrometer based on micro-electronic mechanical system micro-mirrors and single detector. The fundamental principle key parameters of this were analyzed in detail. Theoretical analysis showed that, when the dip angle slantwise mirror is 0.38713°, resolution 9.7 nm (at 1350 nm). Experiments demonstrated spectra less than 10 nm, wavelength deviation ∼1.5 signal-to-noise ratio higher 30 dB intensity at peak 0.4%.

In this paper, we investigate effects of several design parameters, including turn number and unit cell size, on the stopband performance rectangular spiral EBG structure by HFSS. The results conventional are compared. addition, is applied into microstrip antenna. It demonstrated that gain FBR improved.

The proposal of global energy interconnection improves the complexity power grid operation and increases possibility fault occurrence, so diagnosis has become a more urgent need. In this paper, two kinds common faults in distribution network are analyzed, classification models these proposed. One is model transmission line network. types determined by inputting transient signal characteristics into rough neural other to use decision tree identify characteristic parameters transformer after...

Fiber optic acoustic sensing system based on Sagnac interference is widely used in the field of perimeter security. However, sensitivity response varies drastically with frequency, which has become a bottleneck limiting development photoacoustic technology. An elastic structure proposed to improve consistency at different frequencies. The optical fiber pickup was optimized by finite element analysis, Solidworks and Comsol. Simulation results show that designed titanium alloy-based...

The photoacoustic sensor system based on Sagnac interference has extensive applications in perimeter security. Among them, the demand for synchronization recognition of multiple acoustic sources and integrated utilization becomes key to expand its application field. By focusing multi-source recognition, a lightweight optical-acoustic signal algorithm that can be carried by an embedded was studied. collected signals were extracted through preprocessing, Fast Fourier Transform (FFT), Mel...

Based on the coupled mode theory by using reversely recursive transmission matrix method, switching characteristics of λ/4 phase-shifted fiber grating and influence introducing chirp have been numerically studied when reflection facet is taken into consideration. The results show: for coherent superposition strengthening, it can reduce threshold energy grating, but contrast will decline; with introduction negative in be greatly improved, increase; positive further reduced, hysteresis loop...