scholarly journals The Multisensor Array Based on Grown-On-Chip Zinc Oxide Nanorod Network for Selective Discrimination of Alcohol Vapors at Sub-ppm Range

Sensors ◽  
2019 ◽  
Vol 19 (19) ◽  
pp. 4265 ◽  
Author(s):  
Anton Bobkov ◽  
Alexey Varezhnikov ◽  
Ilya Plugin ◽  
Fedor S. Fedorov ◽  
Vanessa Trouillet ◽  
...  

We discuss the fabrication of gas-analytical multisensor arrays based on ZnO nanorods grown via a hydrothermal route directly on a multielectrode chip. The protocol to deposit the nanorods over the chip includes the primary formation of ZnO nano-clusters over the surface and secondly the oxide hydrothermal growth in a solution that facilitates the appearance of ZnO nanorods in the high aspect ratio which comprise a network. We have tested the proof-of-concept prototype of the ZnO nanorod network-based chip heated up to 400 °C versus three alcohol vapors, ethanol, isopropanol and butanol, at approx. 0.2–5 ppm concentrations when mixed with dry air. The results indicate that the developed chip is highly sensitive to these analytes with a detection limit down to the sub-ppm range. Due to the pristine differences in ZnO nanorod network density the chip yields a vector signal which enables the discrimination of various alcohols at a reasonable degree via processing by linear discriminant analysis even at a sub-ppm concentration range suitable for practical applications.

Sensors ◽  
2021 ◽  
Vol 21 (6) ◽  
pp. 2110
Author(s):  
Ensaf Mohammed Al-Khalqi ◽  
Muhammad Azmi Abdul Hamid ◽  
Naif H. Al-Hardan ◽  
Lim Kar Keng

For highly sensitive pH sensing, an electrolyte insulator semiconductor (EIS) device, based on ZnO nanorod-sensing membrane layers doped with magnesium, was proposed. ZnO nanorod samples prepared via a hydrothermal process with different Mg molar ratios (0–5%) were characterized to explore the impact of magnesium content on the structural and optical characteristics and sensing performance by X-ray diffraction analysis (XRD), atomic force microscopy (AFM), and photoluminescence (PL). The results indicated that the ZnO nanorods doped with 3% Mg had a high hydrogen ion sensitivity (83.77 mV/pH), linearity (96.06%), hysteresis (3 mV), and drift (0.218 mV/h) due to the improved crystalline quality and the surface hydroxyl group role of ZnO. In addition, the detection characteristics varied with the doping concentration and were suitable for developing biomedical detection applications with different detection elements.


2013 ◽  
Vol 750-752 ◽  
pp. 253-258
Author(s):  
Li Rong Yang ◽  
Jun Cong Wei ◽  
Li Zhang ◽  
Hai Bin Chen

Well-aligned ZnO nanorod arrays on Chaleted Sol-Gel-Derived ZnO thin films was achieved at a temperature of 90°C by a surfactant-assisted soft chemical approach. The nanorod arrays were characterized by XRD, SEM, XPS, and UV-Vis absorbance spectra. The ZnO nanorod arrays are wurtzite crystal stuctures preferentially orienting in the direction of the c-axis and ZnO nanorods are grown verticallyon the substrate. The XPS analysis shows the Zn:O ratio of ZnO nanorod arrays near is 1:1. The UV-Vis absorbance spectra indicate that ZnO nanorod arrays have absorption of visible-light as well as ultraviolet-light. Therefore, the ZnO nanorods may be good candidates for visible-light photocatalysis materials from the viewpoint of practical applications.


RSC Advances ◽  
2019 ◽  
Vol 9 (18) ◽  
pp. 10117-10123 ◽  
Author(s):  
Parisa Fakhri ◽  
Babak Amini ◽  
Roohollah Bagherzadeh ◽  
Mohammad Kashfi ◽  
Masoud Latifi ◽  
...  

A novel hybrid piezoelectric structure based on electrospun PVDF NFs and vertically grown ZnO nanorods is presented as a promising nanogenerator to convert mechanical movement more efficiently into electricity for practical applications.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Kanako Saito ◽  
Yuri Ota ◽  
Dieter M. Tourlousse ◽  
Satoko Matsukura ◽  
Hirotsugu Fujitani ◽  
...  

AbstractDroplet microfluidics has emerged as a powerful technology for improving the culturing efficiency of environmental microorganisms. However, its widespread adoption has been limited due to considerable technical challenges, especially related to identification and manipulation of individual growth-positive droplets. Here, we combined microfluidic droplet technology with on-chip “fluorescent nucleic acid probe in droplets for bacterial sorting” (FNAP-sort) for recovery of growth-positive droplets and droplet microdispensing to establish an end-to-end workflow for isolation and culturing of environmental microbes. As a proof-of-concept, we demonstrate the ability of our technique to yield high-purity cultures of rare microorganisms from a representative complex environmental microbiome. As our system employs off-the-shelf commercially available equipment, we believe that it can be readily adopted by others and may thus find widespread use toward culturing the high proportion of as-of-yet uncultured microorganisms in different biomes.


Actuators ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 30
Author(s):  
Pornthep Preechayasomboon ◽  
Eric Rombokas

Soft robotic actuators are now being used in practical applications; however, they are often limited to open-loop control that relies on the inherent compliance of the actuator. Achieving human-like manipulation and grasping with soft robotic actuators requires at least some form of sensing, which often comes at the cost of complex fabrication and purposefully built sensor structures. In this paper, we utilize the actuating fluid itself as a sensing medium to achieve high-fidelity proprioception in a soft actuator. As our sensors are somewhat unstructured, their readings are difficult to interpret using linear models. We therefore present a proof of concept of a method for deriving the pose of the soft actuator using recurrent neural networks. We present the experimental setup and our learned state estimator to show that our method is viable for achieving proprioception and is also robust to common sensor failures.


2021 ◽  
Vol 15 (2) ◽  
pp. 024113
Author(s):  
Hoi Kei Chiu ◽  
Tadas Kartanas ◽  
Kadi L. Saar ◽  
Carina Mouritsen Luxhøj ◽  
Sean Devenish ◽  
...  

2020 ◽  
Vol 20 (6) ◽  
pp. 3512-3518
Author(s):  
Saleh Khan ◽  
Xiao-He Liu ◽  
Xi Jiang ◽  
Qing-Yun Chen

Highly efficient and effective porous ZnO nanorod arrays were fabricated by annealing ZnO nanorod arrays grown on a substrate using a simple hydrothermal method. The annealing had a positive effect on the nanorod morphology, structure and optical properties. The porosity was closely related to the annealing temperature. After heating at 450 °C, pores appeared on the nanorods. It was demonstrated that the porosity could be exploited to improve the visible light absorption of ZnO and reduce the bandgap from 3.11 eV to 2.99 eV. A combination of improved charge separation and transport of the heat-treated ZnO thus led to an increase in the photoelectrochemical properties. At an irradiation intensity of 100 mW/cm−2, the photocurrent density of the porous nanorod array was approximately 1.3 mA cm−2 at 1.2 V versus Ag/AgCl, which was five times higher than that of the ZnO nanorods. These results revealed the synthesis of promising porous ZnO nanorods for photoelectrochemical applications.


CrystEngComm ◽  
2017 ◽  
Vol 19 (41) ◽  
pp. 6085-6088 ◽  
Author(s):  
Amany Ali ◽  
DongBo Wang ◽  
JinZhong Wang ◽  
ShuJie Jiao ◽  
FengYun Guo ◽  
...  

The ultraviolet luminescence of ZnO nanorods was greatly enhanced through introducing an AlN buffer layer.


Author(s):  
Jing Jin ◽  
Hua Fang ◽  
Ian Daly ◽  
Ruocheng Xiao ◽  
Yangyang Miao ◽  
...  

The common spatial patterns (CSP) algorithm is one of the most frequently used and effective spatial filtering methods for extracting relevant features for use in motor imagery brain–computer interfaces (MI-BCIs). However, the inherent defect of the traditional CSP algorithm is that it is highly sensitive to potential outliers, which adversely affects its performance in practical applications. In this work, we propose a novel feature optimization and outlier detection method for the CSP algorithm. Specifically, we use the minimum covariance determinant (MCD) to detect and remove outliers in the dataset, then we use the Fisher score to evaluate and select features. In addition, in order to prevent the emergence of new outliers, we propose an iterative minimum covariance determinant (IMCD) algorithm. We evaluate our proposed algorithm in terms of iteration times, classification accuracy and feature distribution using two BCI competition datasets. The experimental results show that the average classification performance of our proposed method is 12% and 22.9% higher than that of the traditional CSP method in two datasets ([Formula: see text]), and our proposed method obtains better performance in comparison with other competing methods. The results show that our method improves the performance of MI-BCI systems.


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