Fabrication and calibration of nanostructured Vanadium-doped ZnO-based micromachined sensor with superior sensitive for underwater acoustic measurement

Author(s):  
Wei Gao ◽  
Yu Zhang ◽  
Bing he Ma ◽  
Jian Luo ◽  
Jinjun Deng

Abstract A high-performance micromachined piezoelectric sensor based nanostructured Vanadium-doped Zinc oxide (ZnO) film with air-backing has been developed and characterized for underwater acoustic application. The sensing cell with a low foot-print of 2.0 mm × 2.0 mm is fabricated by MEMS technology using a ZnO-on-SOI process platform. An optimal ratio of piezoelectric coefficient to the relative permittivity is obtained about 6.3 in the Zn0.98V0.02O sensing cell, improving by an order of magnitude compared with other notable piezoelectric films, plays a mainly dominant role in the enhanced piezoelectric response. Calibrations in the standard underwater instrument have demonstrated that the presented sensor could achieve an acoustic pressure sensitivity of −165 ± 2 dB (Ref. 1 V/μPa) over a bandwidth 10 Hz to 10 kHz, outperforming the same kind of reported devices. The maximum non-linearity is no more than 0.3% and the sensitivity variation is no more than ± 0.7 dB in the temperature range from 10℃ to 50 ℃ indicating a better stability and higher reliability. The proposed sensor with a superior acoustic sensitivity gives a great application potential in underwater acoustic measurements.

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Santu Bera ◽  
Sarah Guerin ◽  
Hui Yuan ◽  
Joseph O’Donnell ◽  
Nicholas P. Reynolds ◽  
...  

AbstractRealization of a self-assembled, nontoxic and eco-friendly piezoelectric device with high-performance, sensitivity and reliability is highly desirable to complement conventional inorganic and polymer based materials. Hierarchically organized natural materials such as collagen have long been posited to exhibit electromechanical properties that could potentially be amplified via molecular engineering to produce technologically relevant piezoelectricity. Here, by using a simple, minimalistic, building block of collagen, we fabricate a peptide-based piezoelectric generator utilising a radically different helical arrangement of Phe-Phe-derived peptide, Pro-Phe-Phe and Hyp-Phe-Phe, based only on proteinogenic amino acids. The simple addition of a hydroxyl group increases the expected piezoelectric response by an order of magnitude (d35 = 27 pm V−1). The value is highest predicted to date in short natural peptides. We demonstrate tripeptide-based power generator that produces stable max current >50 nA and potential >1.2 V. Our results provide a promising device demonstration of computationally-guided molecular engineering of piezoelectricity in peptide nanotechnology.


Actuators ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 62
Author(s):  
Ilia Uvarov ◽  
Pavel Shlepakov ◽  
Artem Melenev ◽  
Kechun Ma ◽  
Vitaly Svetovoy ◽  
...  

Microfluidic devices providing an accurate delivery of fluids at required rates are of considerable interest, especially for the biomedical field. The progress is limited by the lack of micropumps, which are compact, have high performance, and are compatible with standard microfabrication. This paper describes a micropump based on a new driving principle. The pump contains three membrane actuators operating peristaltically. The actuators are driven by nanobubbles of hydrogen and oxygen, which are generated in the chamber by a series of short voltage pulses of alternating polarity applied to the electrodes. This process guaranties the response time of the actuators to be much shorter than that of any other electrochemical device. The main part of the pump has a size of about 3 mm, which is an order of magnitude smaller in comparison with conventional micropumps. The pump is fabricated in glass and silicon wafers using standard cleanroom processes. The channels are formed in SU-8 photoresist and the membrane is made of SiNx. The channels are sealed by two processes of bonding between SU-8 and SiNx. Functionality of the channels and membranes is demonstrated. A defect of electrodes related to the lift-off fabrication procedure did not allow a demonstration of the pumping process although a flow rate of 1.5 µl/min and dosage accuracy of 0.25 nl are expected. The working characteristics of the pump make it attractive for the use in portable drug delivery systems, but the fabrication technology must be improved.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Amir Muhammad Afzal ◽  
In-Gon Bae ◽  
Yushika Aggarwal ◽  
Jaewoo Park ◽  
Hye-Ryeon Jeong ◽  
...  

AbstractHybrid organic–inorganic perovskite materials provide noteworthy compact systems that could offer ground-breaking architectures for dynamic operations and advanced engineering in high-performance energy-harvesting optoelectronic devices. Here, we demonstrate a highly effective self-powered perovskite-based photodiode with an electron-blocking hole-transport layer (NiOx). A high value of responsivity (R = 360 mA W−1) with good detectivity (D = 2.1 × 1011 Jones) and external quantum efficiency (EQE = 76.5%) is achieved due to the excellent interface quality and suppression of the dark current at zero bias voltage owing to the NiOx layer, providing outcomes one order of magnitude higher than values currently in the literature. Meanwhile, the value of R is progressively increased to 428 mA W−1 with D = 3.6 × 1011 Jones and EQE = 77% at a bias voltage of − 1.0 V. With a diode model, we also attained a high value of the built-in potential with the NiOx layer, which is a direct signature of the improvement of the charge-selecting characteristics of the NiOx layer. We also observed fast rise and decay times of approximately 0.9 and 1.8 ms, respectively, at zero bias voltage. Hence, these astonishing results based on the perovskite active layer together with the charge-selective NiOx layer provide a platform on which to realise high-performance self-powered photodiode as well as energy-harvesting devices in the field of optoelectronics.


2021 ◽  
Author(s):  
Sara Reichenbach ◽  
Benjamin Kromoser ◽  
Philipp Preinstorfer ◽  
Tobias Huber

<p>With the building industry being one of the main sources of carbon dioxide emission worldwide and concrete being the main construction material, new strategies have to be developed to reduce the carbon footprint thereof. The use of high-performance materials in structural concrete, as for example textile-reinforced concrete (TRC), seems to allow for a reduction of the resource consumption and the carbon emissions. The present paper addresses potential applications of TRC examining the global warming potential (GWP) of a rail platform barrier. The resource consumption is depicted in a parametrical study in terms of the necessary component height and reinforcement area considering both the serviceability limit state (SLS) as well as the ultimate limit state (ULS). The results clearly indicate an achievable reduction of the GWP during construction when using textile reinforcement made of high-performance fibres. Furthermore, an analysis of the European market was conducted to prove the availability of this new reinforcement type. </p>


2012 ◽  
Vol 81 ◽  
pp. 65-74 ◽  
Author(s):  
Jacopo Iannacci ◽  
Giuseppe Resta ◽  
Paola Farinelli ◽  
Roberto Sorrentino

MEMS (MicroElectroMechanical-Systems) technology applied to the field of Radio Frequency systems (i.e. RF-MEMS) has emerged in the last 10-15 years as a valuable and viable solution to manufacture low-cost and very high-performance passive components, like variable capacitors, inductors and micro-relays, as well as complex networks, like tunable filters, reconfigurable impedance matching networks and phase shifters, and so on. The availability of such components and their integration within RF systems (e.g. radio transceivers, radars, satellites, etc.) enables boosting the characteristics and performance of telecommunication systems, addressing for instance a significant increase of their reconfigurability. The benefits resulting from the employment of RF-MEMS technology are paramount, being some of them the reduction of hardware redundancy and power consumption, along with the operability of the same RF system according to multiple standards. After framing more in detail the whole context of RF MEMS technology, this paper will provide a brief introduction on a typical RF-MEMS technology platform. Subsequently, some relevant examples of lumped RF MEMS passive elements and complex reconfigurable networks will be reported along with their measured RF performance and characteristics.


Holzforschung ◽  
2018 ◽  
Vol 73 (1) ◽  
pp. 117-130 ◽  
Author(s):  
Vebi Mimini ◽  
Vasken Kabrelian ◽  
Karin Fackler ◽  
Hubert Hettegger ◽  
Antje Potthast ◽  
...  

AbstractThe bulk use of renewable polymers is currently largely limited to cellulose and, less significantly, hemicelluloses. Technical lignins are only applied in novel materials to a rather limited extent, although bulk lignin utilization is a worldwide research object. Native lignins, which belong to the second or third most abundant biopolymers of terrestrial plants, are mostly used in the form of technical lignins from wood pulping processes; they are employed in low-performance sectors or simply burnt for the generation of energy. Technical lignins are available in huge quantities and have a large application potential, mainly in areas where their aromatic nature is of relevance. This review presents the state of the art of foamed lignin-based polymers (lignofoams) as high-performance insulation materials. In the focus of this presentation are the fundamental foaming principles and influential agents that have an improvement potential concerning the matrix interactions between technical lignins (including lignosulfonates) and a copolymer in foam composites. The different approaches for foam preparation are critically compared. In general, the reviewed papers disclose that the lignin part in foams should be less than 37%. There are significant difficulties to improve the properties of lignofoams, and thus intensive research is needed to find better formulations and new technologies.


2020 ◽  
Author(s):  
Tuan Pham

Chest X-rays have been found to be very promising for assessing COVID-19 patients, especially for resolving emergency-department and urgent-care-center overcapacity. Deep-learning (DL) methods in artificial intelligence (AI) play a dominant role as high-performance classifiers in the detection of the disease using chest X-rays. While many new DL models have been being developed for this purpose, this study aimed to investigate the fine tuning of pretrained convolutional neural networks (CNNs) for the classification of COVID-19 using chest X-rays. Three pretrained CNNs, which are AlexNet, GoogleNet, and SqueezeNet, were selected and fine-tuned without data augmentation to carry out 2-class and 3-class classification tasks using 3 public chest X-ray databases. In comparison with other recently developed DL models, the 3 pretrained CNNs achieved very high classification results in terms of accuracy, sensitivity, specificity, precision, F1 score, and area under the receiver-operating-characteristic curve. AlexNet, GoogleNet, and SqueezeNet require the least training time among pretrained DL models, but with suitable selection of training parameters, excellent classification results can be achieved without data augmentation by these networks. The findings contribute to the urgent need for harnessing the pandemic by facilitating the deployment of AI tools that are fully automated and readily available in the public domain for rapid implementation.


2020 ◽  
Author(s):  
Marcus H. Hansen ◽  
Anita T. Simonsen ◽  
Hans B. Ommen ◽  
Charlotte G. Nyvold

AbstractBackgroundRapid and practical DNA-sequencing processing has become essential for modern biomedical laboratories, especially in the field of cancer, pathology and genetics. While sequencing turn-over time has been, and still is, a bottleneck in research and diagnostics, the field of bioinformatics is moving at a rapid pace – both in terms of hardware and software development. Here, we benchmarked the local performance of three of the most important Spark-enabled Genome analysis toolkit 4 (GATK4) tools in a targeted sequencing workflow: Duplicate marking, base quality score recalibration (BQSR) and variant calling on targeted DNA sequencing using a modest hyperthreading 12-core single CPU and a high-speed PCI express solid-state drive.ResultsCompared to the previous GATK version the performance of Spark-enabled BQSR and HaplotypeCaller is shifted towards a more efficient usage of the available cores on CPU and outperforms the earlier GATK3.8 version with an order of magnitude reduction in processing time to analysis ready variants, whereas MarkDuplicateSpark was found to be thrice as fast. Furthermore, HaploTypeCallerSpark and BQSRPipelineSpark were significantly faster than the equivalent GATK4 standard tools with a combined ∼86% reduction in execution time, reaching a median rate of ten million processed bases per second, and duplicate marking was reduced ∼42%. The called variants were found to be in close agreement between the Spark and non-Spark versions, with an overall concordance of 98%. In this setup, the tools were also highly efficient when compared execution on a small 72 virtual CPU/18-node Google Cloud cluster.ConclusionIn conclusion, GATK4 offers practical parallelization possibilities for DNA sequence processing, and the Spark-enabled tools optimize performance and utilization of local CPUs. Spark utilizing GATK variant calling is several times faster than previous GATK3.8 multithreading with the same multi-core, single CPU, configuration. The improved opportunities for parallel computations not only hold implications for high-performance cluster, but also for modest laboratory or research workstations for targeted sequencing analysis, such as exome, panel or amplicon sequencing.


2010 ◽  
Vol 4 (2) ◽  
pp. 110-116 ◽  
Author(s):  
Kiwamu Ashida ◽  
◽  
Shizuka Nakano ◽  
Jaehyuk Park ◽  
Jun Akedo

Many micro-scale devices have been developed by applying micro-electro-mechanical systems (MEMS) technology, but MEMS production facilities are large and costly, making it difficult to develop small numbers of trial devices. The novel on-demand MEMS device production system we developed applies two major concepts – that of the microfactory and the introduction of non-MEMS processes in microfabrication. These two concepts have made manufacturing more ecological, economical, agile, and flexible through downsizing, forming an automated production line by connecting standardized unit-processing cells, each of which has a desktop process, a part transfer robot, and a standardized connection interface. These enable any process cell to be connected in any sequence that the target product requires. Four unit-process cells were developed – the micropress cell for fabricating microstructures from thin sheet metal and the miniature aerosol deposition (AD) process cell for fabricating high-performance piezoelectric (PZT) ceramics actuators. The feasibility of the on-demand MEMS production system was demonstrated by the fabrication of a MEMS-like micromirror scanner, proving the potential of on-demand MEMS production in diversified small-lot production.


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