Considering metal oxide nanoparticles as important technological materials, authors provide a comprehensive review of researches on metal oxide nanoparticles, their synthetic strategies, and techniques, nanoscale physicochemical properties, defining specific industrial applications in the various fields of applied nanotechnology. This work expansively reviews the recent developments of semiconducting metal oxide gas sensors for environmental gases including CO2, O2, O3, and NH3; highly toxic gases including CO, H2S, and NO2; combustible gases such as CH4, H2, and liquefied petroleum gas; and volatile organic compounds gases. The gas sensing properties of different metal oxides nanoparticles towards specific target gases have been individually discussed. Promising metal oxide nanoparticles for sensitive and selective detection of each gas have been identified. This review also categorizes metal oxides sensors by analyte gas and also summarizes the major techniques and synthesis strategies used in nanotechnology. Additionally, strategies, sensing mechanisms and related applications of semiconducting metal oxide materials are also discussed in detail. Related applications are innumerable trace to ultratrace-level gas sensors, batteries, magnetic storage media, various types of solar cells, metal oxide nanoparticles applications in catalysis, energy conversion, and antennas (including microstrip and patch-type optically transparent antennas), rectifiers, optoelectronic, and electronics.

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Metal oxide nanoparticles and their applications in nanotechnology

Graphene nanoribbon based terahertz antenna on polyimide substrate

Graphene is an ideal 2D material system bridging electronic and photonic devices. It also breaks the fundamental speed and size limits by electronics and photonics, respectively. Graphene offers multiple functions of signal transmission, emission, modulation, and detection in a broad band, high speed, compact size, and low loss. Here, we have a brief view of graphene based functional devices at microwave, terahertz, and optical frequencies. Their fundamental physics and computational models were discussed as well.

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Graphene based functional devices: A short review

In this paper, we have presented the simulation results of a rectangular microstrip patch antenna at terahertz (THz) frequency ranging from 0.7 to 0.85 THz. THz electromagnetic wave can permit more densely packed communication links with increased security of communication transmission. The simulated results such as gain, radiation efficiency and 10 dB impedance bandwidth of rectangular microstrip patch antenna at THz frequencies without shorting post configuration are 3.497 dB, 55.71% and 17.76%, respectively, whereas with shorting post configuration, corresponding parameters are 3.502 dB, 55.88% and 17.27%. The simulation has been performed by using CST Microwave Studio, which is a commercially available electromagnetic simulator based on the method of finite difference time domain technique.

Rectangular Microstirp Patch Antenna Design at THz Frequency for Short Distance Wireless Communication Systems

Recent advancement of communication system requires low cost, minimal weight, low profile and high-performance antenna to execute the demand of the future realization. A high gain novel microstrip patch antenna design is proposed, based on the photonic crystal for terahertz (THz) spectral band applications. This antenna is mounted on polyimide substrate that employs Photonic Band Gap (PBG) crystal and the Gain of 7.934 dB, Directivity 8.612 dBi and VSWR close to unity at resonant frequency of 0.6308 THz. The proposed antenna model is compared with homogeneous polyimide substrate structure based microstrip patch antenna and analyzed the radiation characteristics. Moreover, the performance of designed antenna is investigated with different PBG cylindrical distance, PBG hole radius, curvature radius of patch and substrate heights. The projected design antenna has a bandwidth of 36.25 GHz and −10 dB impedance with operating frequency range varying from 0.6152 THz to 0.6514 THz, hence it can be utilized for detection of explosive and material characterization applications.

Design and analysis of novel microstrip patch antenna on photonic crystal in THz

Analysis and design of optically transparent antenna on photonic band gap structures

An optically transparent microstrip patch antenna is designed and its radiation characteristics are analyzed in 706 - 794 GHz band. Terahertz communication systems offer advantages such as broad bandwidth, low transmit power, secured wireless communication and compactness. It has applications in various fields like hidden object detection, imaging and sensing. In the proposed antenna, transparent conducting indium tin oxide thin film is used as a radiating patch and a ground plane material. The entire antenna structure is optically transparent in the visible spectrum region. The proposed antenna is simulated using Ansoft – HFSS, a finite element method (FEM) based electromagnetic solver.

Investigations on Indium Tin Oxide Based Optically Transparent Terahertz E-shaped Patch Antenna

Aim: The aim of this study was to evaluate and to compare the clinical efficacy of two compounds (hydrochloric acid and phosphoric acid) in microabrasion in terms of degree of stain removal (DSR) and improvement of appearance for the different severities of dental fluorosis. The mean time and number of applications required by the two experimental compounds were also compared. Methodology: Children between the age group of 9–14 years with dental fluorosis to two or more fluorozed anterior permanent teeth were included in the study. The Dean's Fluorosis Index was used to classify each tooth, and they were randomly selected into mild (Group I), moderate (Group II), and severe (Group III) groups of fluorosis. Ten teeth from each of these groups were randomly allotted for undergoing microabrasion using 18% HCl with pumice and other 10 teeth using 37% phosphoric acid with pumice. Colored preoperative and postoperative photographs were taken for each patient and analyzed for improvement in appearance and DSR. Time and number of applications and parent–patient response with both the compounds were also recorded. The results were tabulated and statistically analyzed. Results: The results of the present study showed that a nonsignificant difference existed in DSR and improvement in appearance between the two compounds of microabrasion for all the three degrees of dental fluorosis. Significantly lesser time was taken by HCl in mild and moderate fluorosis. Significantly lesser number of applications was required with HCl for moderate fluorosis. Nonsignificant difference existed for parent-patient response with both the compounds for all the severities of dental fluorosis. Conclusion: 18% HCl with pumice and 37% phosphoric acid with pumice both can be used for microabrasion for all the severities of dental fluorosis. The time and number of applications using HCl were lesser; therefore, it should be preferred over H3PO4 for all the severities of fluorosis.

Clinical efficacy of hydrochloric acid and phosphoric acid in microabrasion technique for the treatment of different severities of dental fluorosis: An in vivo comparison

Siddharth Anand

Papers

Graphene nanoribbon based terahertz antenna on polyimide substrate

Analysis and design of optically transparent antenna on photonic band gap structures

Investigations on Indium Tin Oxide Based Optically Transparent Terahertz E-shaped Patch Antenna

Clinical efficacy of hydrochloric acid and phosphoric acid in microabrasion technique for the treatment of different severities of dental fluorosis: An in vivo comparison

Comparative evaluation of antimicrobial potential of ginger, garlic and cinnamon extracts against streptococcus mutans and lactobacillus acidophilus.