Polyimide Humidity Integrated Sensor Fabricated Using the MEMS Process

This paper reports on the fabrication and sensing characteristics of Polyimide-based humidity sensor,based on that,a new integrated circuit of humidity measurement has been designed.It is a novel capacitive-type systems on a chip structure using the MEMS process.The results show that the new sensor presents sensing characteristics over a humidity range from 10%～70% RH at 20℃,and the sensor is able to fabricated together with ICs technology.The result shows that integration of humidity sensor with integrated circuit of humidity measurement is considerably easier when they are built in sensing groove.The appeal of a new structure like this brings the possibility of applications that would require the flexibility of simple screen printing.

Integrated sensor based on acoustics-electricity-mechanics coupling effect for wireless passive gas detection

Integrated sensor combines multiple sensor functions into a single unit,which has the advantages of miniaturization and better application potential.However,limited by the sensing platforms of the sensor and the selectivity of the sensitive film,there are still challenges to realize multi-component gas detection in one unit.Herein,a principle integration method is proposed to achieve the multi-component gas detection based on the acoustics-electricity-mechanics coupling effect.The electrical and mechanical properties of the Bi_(2)S_(3)nanobelts materials in different atmospheres indicate the possibility of realizing the principle integration.At the same time,the surface acoustic wave(SAW)sensor as a multivariable physical transducer can sense both electrical and mechanical properties.Upon exposure to 10 ppm NO_(2),NH_(3),and their mixtures,the integrated SAW gas sensor shows a 4.5 kHz positive frequency shift(acoustoelectric effect),an 11 kHz negative frequency shift(mechanics effects),and a reduced 4 kHz negative frequency shift(acoustics-electricity-mechanics coupling effect),respectively.Moreover,we realize wireless passive detection of NO_(2)and NH_(3)based on the SAW sensor.Our work provides valuable insights that can serve as a guide to the design and fabrication of single sensors offering multi-component gas detection via different gas sensing mechanisms.

Intelligent Deep Learning Enabled Wild Forest Fire Detection System

The latest advancements in computer vision and deep learning(DL)techniques pave the way to design novel tools for the detection and monitoring of forestfires.In this view,this paper presents an intelligent wild forestfire detec-tion and alarming system using deep learning(IWFFDA-DL)model.The pro-posed IWFFDA-DL technique aims to identify forestfires at earlier stages through integrated sensors.The proposed IWFFDA-DL system includes an Inte-grated sensor system(ISS)combining an array of sensors that acts as the major input source that helps to forecast thefire.Then,the attention based convolution neural network with bidirectional long short term memory(ACNN-BLSTM)model is applied to examine and identify the existence of danger.For hyperpara-meter tuning of the ACNN-BLSTM model,the bacterial foraging optimization(BFO)algorithm is employed and thereby enhances the detection performance.Finally,when thefire is detected,the Global System for Mobiles(GSM)modem transmits messages to the authorities to take required actions.An extensive set of simulations were performed and the results are investigated interms of several aspects.The obtained results highlight the betterment of the IWFFDA-DL techni-que interms of various measures.

A STUDY OF THE PIEZOELECTRIC PROPERTIES OF GaAs

The origin of the piezoelectric effect of GaAs is discussed in some detail.TheGa atoms are negatively charged and As atoms positively charged.The piezoelectric con-stant tensors for arbitrarily oriented GaAs have been obtained.It is verified that for nor-mal stress when the GaAs samples are oriented in the 〈111〉 direction the maximumpiezoelectric effect occurs.As far as the piezoelectric properties and fabrication technologyare concerned,〈100〉 oriented GaAs substratcs are fit for the force sensors.

Optimizing the design of GaAs/AlGaAs thin-film waveguides for integrated mid-infrared sensors

Optical simulations of GaAs/AlGaAs thin-film waveguides were performed for investigating the dependence of the modal behavior on waveguide geometry and the resulting analytical sensitivity. Simulations were performed for two distinct mid-infrared wavelengths, thereby demonstrating the necessity of individually designed waveguide structures for each spectral regime of interest. Hence, the modal behavior, sensitivity, and intensity of the evanescent field were investigated via modeling studies at 1600 and 1000 cm^(-1), thereby confirming the utility of such simulations for designing mid-infrared sensors based on thin-film waveguide technology.

Robust and low-cost interrogation technique for integrated photonic biochemical sensors based on Mach–Zehnder interferometers

We describe and experimentally demonstrate a measuring technique for Mach–Zehnder interferometer(MZI)based integrated photonic biochemical sensors. Our technique is based on the direct measurement of phase changes between the arms of the MZI, achieved by signal modulation on one of the arms of the interferometer together with pseudoheterodyne detection, and it allows us to avoid the use of costly equipment such as tunable light sources or spectrum analyzers. The obtained output signal is intrinsically independent of wavelength, power variations, and global thermal variations, making it extremely robust and adequate for use in real conditions. Using a silicon-on-insulator MZI, we demonstrate the real-time monitoring of refractive index variations and achieve a detection limit of 4.1 × 10^(-6)refractive index units(RIU).