About Instruments Today No. 237


Mr. Tim F. Lin, Chairman of Sanlien Technology Education Foundation – Never Let a Good Crisis Go to Waste.

Claire Lin

Smart Dust Technology and Application Observation

Special Issue Introduction of “Smart Dust Technology and Application Observation”

Yung-Yu Chen

Indium Oxide Nanobrick Based and Smart Phone Operated Portable Semiconductor Type Ozone Gas Sensor

Tzu-Hsuan Hsu, Cheng-Bin Hung, Da-Fu Wang, Wei-Chung Su, Yang-Che Sun, Cheng-En Liu, Heh-Nan Lin

This work describes the synthesis of highly O3 sensitive indium oxide nanobricks and the construction of a smart phone operated portable semiconductor type gas sensor. The indium oxide nanobricks are synthesized by a low-cost chemical process. Under UV-activated sensing, a resistance change sensitivity of 22.7 ppm-1 and a lowest detection limit of 1 ppb for O3 sensing are obtained. The sensitivity is around 8 ppm-1 for NO2 and the sensitivity ratio is around 1:0.35. The sensitivities are significantly lower for other gases. The gas sensor is deployed in an air quality monitoring station for machine learning. The chip resistance, the temperature, and the relative humidity are taken as the input values, and the station concentrations the target values. An artificial neural network algorithm has been developed to predict the concentration. A coefficient of determination R2 of 0.48 has been obtained when using 1 O3 + 0.54 NO2 as the target concentration.

A Tuned Mass Damper Based Micromechanical Mass Sensor

Wen-Ruei Du, Jia-Ren Liu, Ting-Yi Chen, Wei-Chang Li

Micromechanical resonators, of which their resonance frequencies change in response to environmental perturbations, could be used as sensors. To date, Resonant-type sensors are the most widely adopted sensing mechanism in numerous application fields, including mass sensors, force sensors, electrometers, etc. Compared to regular micromechanical sensing devices, i.e., cantilever beam resonators, this article uses a tuned-mass-damper-based resonator for mass sensing applications to achieve higher sensitivity. This article is organized as follows: (1) physical models,(2) measurement set-up, and (3) measurement results.

Application of NO Gas Sensor with Circuit Module

Chun-Wei Chiu, Ray-Hua Horng

Due to the development of Internet of Things (IoT), there is a large demand for various types of sensors, among which gas sensors are also one of them. The nitric oxide gas sensor developed in our lab is a semiconductor gas sensor, which has the advantages of high response, fast response, low cost and small size. Nitric oxide is mostly used in environmental monitoring, mainly from the emissions of automobiles and factories, and low concentration of nitric oxide can also detect asthma, and if it can be measured at low concentration, it can be used in medical applications, which will have a significant impact on the healthcare industry. The general semiconductor process for the production of the sensor, you need to use semiconductor measurement equipment to measure the electrical changes, the laboratory has developed a sensing circuit module, greatly reducing the size of the measurement machine and low cost, so that it can be placed in different venues, without space constraints to the actual environment of the test, in addition to reducing the size of the measurement results also have an advantage.

Investigation and Characterization of Methanol Gas Sensor for the ZnO Nanostructures with Adsorbed Au Nanoparticles

Yen-Lin Chu, Wei-Hong Li, Sheng-Joue Young

High-density and well-aligned zinc oxide (ZnO) nanostructures and adsorbed gold (Au) nanoparticles grown on indium tin oxide (ITO) glass substrates were used as gas materials. Through a simple hydrothermal method and at different deposition times of the DC sputtering system (0 s、30 s), the nanorod (NR) arrays adsorbed by Au nanoparticles were successfully grown on the substrate to produce gas-sensing devices. Through instrument analysis [scanning electron microscope (SEM), energy-dispersive spectroscopy (EDS), X-ray diffraction (XRD), photoluminescence (PL), transmission electron microscopy (TEM)], the surface morphology of nanostructure, crystallinity of the material, optical property, and distribution of element content were observed, confirming the successful adsorption of Au nanoparticles on the nanostructure. In the device section, the response values of ZnO nanorods with or without Au nanoparticles adsorption to 1000 ppm methanol were 63% and 41%, respectively, and showed good characteristics at operating temperature of 150 °C and methanol concentration of 1000 ppm. This further confirms that Au nanoparticles can not only effectively improve the sensitivity of the sensor but also enhance the stability of the sensing device.

Design of Microelectromechanical Heater Thermal Analysis Simulation and Verification

Bo-Ming Huang, Yu-Jen Hsiao

Microheaters are developed for higher conversion rates of input power to operating heat, lower energy consumption, faster response times, precise temperature control and in smaller size. This research mainly focuses on the design and manufacture of a micro-heaters combined with bottom heating and gas sensing applications. Along with the main purpose of analyzing energy consumption, temperature distribution and using this component for development and simulation. Simulation comparison of 4 heating electrodes with different geometric designs are compared for less energy consumption design and are developed using micro-electromechanical technology processes.


A Novel Gas-prism Applied on the Inspection of Gas Refractive-index

Hsing-Min Tu, An-Chi Wei, Jyh-Rou Sze

In this research, we present a new system for real-time inspection of gas refractive-index. The system combines with an optical prism to measure the refraction by the deviation angle. A Shack-Hartmann wavefront sensor is also used in this system to analyze the wavefront change resulting from the different refractive indexes of gas. In this system, we use a plane wave as a light source to collaborate with the wavefront sensor. Also, the system applies a single-light-path design which is easier for adjustment or calibrations.

The Secrets of Improving Image Quality of Remote Sensing Satellites Unboxing the Only Large-diameter Aspherical Lens in Taiwan

Po-Li Chen, Claire Lin, Chong-Lun Wei, Tzu-Yu Chuang