Detection Device Research Articles

Inorganic Semiconductor-Based Flexible UV Photodetector Arrays Achieved by Specific Flip-Chip Bonding.

In recent years, flexible UV photodetectors (PDs) with complex environmental adaptability and great wearability have attracted the attention of researchers worldwide. Wide bandgap inorganic semiconductor materials with excellent optoelectronic properties and mechanical stability are key functional materials for UV PD devices. However, the high temperature processing and inherent brittleness limit the further application of high-quality inorganic semiconductors in the field of flexible optoelectronics. In this work, we develop a specific flip-chip bonding fabrication technique that utilizes high-temperature treated inorganic semiconductor materials for high-performance flexible UV detection devices. Leveraging this technique, a 7 × 7 pixel flexible UV photodetector array (UV-FPDA) device based on a vertical architecture Mg-doped ZnO/NiO (Mg:ZnO/NiO) heterojunction transistor is built. The UV-FPDAs exhibit a high responsivity of 75.8 A/W and an outstanding detectivity of 8.5 × 1012 Jones. Besides, the UV-FPDAs also demonstrate excellent bending stability. Furthermore, the photoresponse characteristics of each pixel are trained and learned by an artificial neural network to achieve clear imaging of UV light information. Our results provide a new pathway for the application of inorganic semiconductors in the field of high-performance flexible UV photodetection.

Sodium alginate supramolecular nanofibers in synergy with surface crack engineering to prepare tough and highly sensitive hydrogels

Soft and wet hydrogels often struggle to achieve both toughness and high sensitivity simultaneously, limiting their usefulness in flexible devices. To tackle this challenge, we devised a strategy that combines supramolecular sodium alginate nanofibers, utilizing Zr4+ as physical crosslinkers, with surface crack engineering via the micro-phase separation of polyaniline, to create a physically and chemically dual crosslinked polyacrylamide (PAM)/sodium alginate (SA)/polyaniline (PANI) hydrogel with exceptional toughness and high sensitivity. Owing to the supramolecular sodium alginate nanofibers, the dual crosslinked hydrogel exhibited a tensile strength of 0.391 MPa, an elongation at break of 568.9 %, and a toughness of 1.020 MJ/m3. The in-situ polymerized polyaniline layer, confined within the dense network, introduced micro-cracks onto the hydrogel surface, resulting in a high gauge factor of 11.4 for the fabricated hydrogel. Furthermore, integrating this hydrogel into a triboelectric nanogenerator transformed it into self-powered sensors capable of detecting external forces and generating various signals without power supply. These findings suggest that the developed hydrogel held great potential in diverse fields, including human motion detection, human-machine interaction, and wearable electronic devices.

An all-in-one smartphone-assisted ratiometric fluorescent device for visual and quantitative detection of glutathione

The daily consumption of foods abundant in Glutathione (GSH) can be supplemented to maintain the homeostasis of GSH in human health and alleviate pathologies resulting from abnormal GSH levels. The fluorescence-based visual determination of GSH has gradually attracted the attention of researchers due to its robust performance and versatile implementation. However, the current GSH visual strategy primarily relies on variations in fluorescence intensity at a single emission wavelength, which poses challenges for naked-eye and portable readout, as well as distorted signals caused by complex matrix effects in real samples. Herein, a ratiometric fluorescence sensor based on carbon dots (CDs) combined with an all-in-one 3D-printed smartphone-based device was successfully developed for low-cost, visual and rapid detection of GSH without the need for an external excitation light source. The ratiometric fluorescent materials were synthesized by conjugating blue carbon dots (B-CDs) with yellow carbon dots (Y-CDs) through the utilization of selected Cu2+ ions. The resulting mechanism demonstrated that the coordination interaction between Cu2+ and residual aromatic amino groups in Y-CDs (Y-CDs-Cu2+) contributed to a newly emitted peak at 580 nm, thereby inducing fluorescence resonance energy transfer from B-CDs to Y-CDs-Cu2+. A linear correlation was found between GSH concentrations and R/B values in the range of 10–100 μM, with a limit of detection observed at 4.8 μM. By utilizing this portable device in combination with RGB analysis, the quantitative detection of GSH can be achieved even in complex food matrices such as tomatoes and grapes. The universality of this all-in-one device was further validated by pre-spraying CDs onto a paper strip for visual measurement of GSH. This work offers a portable, visual, and accessible approach to evaluating food safety and nutrition, thereby demonstrating significant economic value and holding profound implications for human health.

Enhanced CRISPR/Cas-Based Immunoassay through Magnetic Proximity Extension and Detection.

Clustered regularly interspaced short palindromic repeats (CRISPR)/Cas-associated systems have recently emerged as a focal point for developing next-generation molecular diagnosis, particularly for nucleic acid detection. However, the detection of proteins is equally critical across diverse applications in biology, medicine, and the food industry, especially for diagnosing and prognosing diseases like cancer, Alzheimer's and cardiovascular conditions. Despite recent efforts to adapt CRISPR/Cas systems for protein detection with immunoassays, these methods typically achieved sensitivity only in the femtomolar to picomolar range, underscoring the need for enhanced detection capabilities. To address this, we developed CRISPR-AMPED, an innovative CRISPR/Cas-based immunoassay enhanced by magnetic proximity extension and detection. This approach combines proximity extension assay (PEA) with magnetic beads that converts protein into DNA barcodes for quantification with effective washing steps to minimize non-specific binding and hybridization, therefore reducing background noise and increasing detection sensitivity. The resulting DNA barcodes are then detected through isothermal nucleic acid amplification testing (NAAT) using recombinase polymerase amplification (RPA) coupled with the CRISPR/Cas12a system, replacing the traditional PCR. This integration eliminates the need for thermocycling and bulky equipment, reduces amplification time, and provides simultaneous target and signal amplification, thereby significantly boosting detection sensitivity. CRISPR-AMPED achieves attomolar level sensitivity, surpassing ELISA by over three orders of magnitude and outperforming existing CRISPR/Cas-based detection systems. Additionally, our smartphone-based detection device demonstrates potential for point-of-care applications, and the digital format extends dynamic range and enhances quantitation precision. We believe CRISPR-AMPED represents a significant advancement in the field of protein detection.

STOCHASTIC FIRE BRIGADE INTERVENTION MODEL

The article is a continuation of a previously published paper, which, based on an analysis of availableglobal literature, provides an overview of firefighting operational models. It outlines the conceptof a stochastic model, which was implemented in the Aamks software to assess the fire risk ofbuildings, developed several years ago and systematically further expanded at the Fire University.It consists of four main time modules: the time of notifying about a fire, the time from receivinginformation about an incident until the moment of dispatch, the time of arriving at the sceneof the incident and the time from the moment of arrival to the moment of starting firefightingactivities. Their majority were determined in a probabilistic way, while some of them, such asthe fire monitoring notification system and selected elements of the final stage, were assessed ina deterministic way. The paper discusses methods of their estimation, particularly in terms ofthe used data. The developed model consists of two main action phases, each subdivided intosmaller stages, the sum of which gives the time taken to undertake extinguishing actions. Thistime is presented as a probability distribution. The first phase, i.e. the notification of the incident,is variable and depends on the equipment of the building with detection devices. As a result of thevariability of the first phase of action, three different but invariable paths have been identified. Theresults in the form of extinguishing action times, along with the probabilities for each variant, arepresented in three result tables at the end of the article.

Development of aptamer-based lateral flow devices for rapid detection of SARS-CoV-2 S protein and uncertainty assessment

The outbreak and spread of COVID-19 have highlighted the urgent need for early diagnosis of SARS-CoV-2. Nucleic acid testing as an authoritative tool, is cumbersome, time-consuming, and easy to cross-infect, while the available antibody self-testing kits are deficient in sensitivity and stability. In this study, we developed competitive aptamer-based lateral flow devices (Apt-LFDs) for the quantitative detection of SARS-CoV-2 spike (S) protein. Molecular docking simulation was used to analyze the active binding sites of the aptamer to S protein, guiding complementary DNA (cDNA) design. Then a highly efficient freezing strategy was applied for the conjugation of gold nanoparticles (AuNPs) and DNA probes. Under optimal conditions, the linear range of the constructed Apt-LFDs was 0.1–1 μg/mL, and the limit of detection (LOD) was 51.81 ng/mL. The cross-reactivity test and stability test of the Apt-LFDs showed good specificity and reliability. The Apt-LFDs had recoveries ranging from 89.45 % to 117.12 % in pharyngeal swabs. Notably, the uncertainty of the analytical result was evaluated using a “bottom-up” approach. At a 95 % confidence level, the uncertainty report of (453.37±54.86) ng/mL with k = 2 was yielded. Overall, this study provides an important reference for the convenient and reliable detection of virus proteins based on LFDs.

Quantitative Risk Assessment of an Oil-Gas-Hydrogen-Electricity Integrated Energy Station in China.

This paper presents a quantitative risk assessment (QRA) study of an oil-gas-hydrogen-electricity integrated energy station in China. A comprehensive assessment of the station was made in terms of consequences and risks, respectively. Consequence analysis shows that the severity of hazardous chemical leakage accidents in the station is in the order of natural gas, hydrogen, gasoline, and diesel fuel, especially in the liquefied natural gas (LNG) and compressed natural gas (CNG) storage tank areas, which may cause major accidents in the event of leakage. The results of the risk assessment showed that the individual and societal risks of the integrated oil-gas-hydrogen-electricity energy station exceeded the risk acceptance criteria. Moreover, the catastrophic rupture of LNG and CNG storage tanks is the main cause of the unacceptable risk. Additional mitigation measures for them, mainly including the installation of emergency manual shut-off valves, the installation of combustible gas detection and alarm devices, and pressure relief protection devices, can effectively reduce the risk to an acceptable level.

Insights into the Mechanisms of Single-Photon and Two-Photon Excited Surface Enhanced Fluorescence by Submicrometer Silver Particles.

Surface enhanced fluorescence (SEF) based on noble metal nanoparticles is an effective means to achieve high sensitivity in fluorescence detection. Currently, the physical mechanism behind enhanced fluorescence is not fully understood. This paper measures the fluorescence signals of Dihydroporphyrin f methyl ether (CPD4) under both single-photon and two-photon excitation based on submicrometer silver particles with rough morphologies, achieving enhancement factors of 34 and 45 times, respectively. On this basis, by combining the radiative field characteristics produced by the silver particles, a stimulated radiation model of molecules is established to elucidate the changes in the molecular photophysical process when influenced by silver particles. Moreover, the fluorescence lifetime of the molecules was measured, showing that the presence of silver particles induces an increase in the molecular radiative decay rate, causing the fluorescence lifetime to decay from 3.8 ns to 3 ns. The results indicate that the fluorescence enhancement primarily originates from the submicrometer silver particles' enhancement effect on the excitation light. Additionally, the fluorescence signal emitted by the molecules couples with the silver particles, causing the local surface plasmon resonances generated by the silver particles to also emit light signals of the same frequency. Under the combined effect, the fluorescence of the molecules is significantly enhanced. The findings provide a theoretical foundation for understanding the fluorescence enhancement mechanism of silver particles, adjusting the enhancement effect, and developing enhanced fluorescence detection devices based on submicrometer silver particles, holding significant practical importance.

Design and Performance Evaluation of an In Situ Online Soil Electrical Conductivity Sensor Prototype Based on the High-Performance Integrated Chip AD5941

Soil electrical conductivity has an important influence on the growth and development of plants. The existing real-time soil electrical conductivity detection device is affected by temperature, inconvenient to use, expensive, etc.; therefore, based on the classical four-terminal method of soil electrical conductivity detection principle, in this study, we aim to improve the limitations of the constant current source, selecting the high-performance integrated chip AD5941, optimizing the detection circuit and probe structure, improving the achievability of the detection circuit, and designing a type of in situ on-line real-time access to a soil electrical conductivity detection device, and improve the detection accuracy by temperature compensation. In this paper, dynamic performance, steady state performance, radial sensitivity range, and calibration test are carried out for the soil electrical conductivity detection prototype. The test results show that the dynamic response speed of the prototype is less than 50 ms, the steady state error is not more than ±2%, and the radial measurement sensitivity range is 8~10 cm. A comparison with the commercial sensor shows that the linear fit of the two measurements reaches 0.9995, and the absolute error ranges from −61.40 µS/cm to 23.90 µS/cm, with a relative error range of −1.94~1.86%. It shows that the performance of the two sensors is comparable, but the quality/price ratio of the prototype is much higher than that of the commercialized product. In this study, it is demonstrated that a high-precision, low-cost, and easy-to-use in situ online soil electrical conductivity detection device can be provided for agricultural and forestry production.

Early-Stage Prototype Assessment of Cost-Effective Non-Intrusive Wearable Device for Instant Home Fetal Movement and Distress Detection: A Pilot Study.

Clinical fetal monitoring devices can only be operated by medical professionals and are overly costly, prone to detrimental false positives, and emit radiation. Thus, highly accurate, easily accessible, simplified, and cost-effective fetal monitoring devices have gained an enormous interest in obstetrics. In this study, a cost-effective and user-friendly wearable home fetal movement and distress detection device is developed and assessed for early-stage design progression by facilitating continuous, comfortable, and non-invasive monitoring of the fetus during the final trimester. The functionality of the developed prototype is mainly based on a microcontroller, a single accelerometer, and a specialized fetal phonocardiography (fPCG) acquisition board with a low-cost microphone. The developed system is capable of identifying fetal movement and monitors fetal heart rhythm owing to its considerable sensitivity. Further, the device includes a Global System for Mobile Communication (GSM)-based alert system for instant distress notifications to the mother, proxy, and emergency services. By incorporating digital signal processing, the system achieves zero false negatives in detecting fetal movements, which was validated against an open-source database. The acquired results clearly substantiated the efficacy of the fPCG acquisition board and alarm system, ensuring the prompt identification of fetal distress.

Assessment of NavVis VLX and BLK2GO SLAM Scanner Accuracy for Outdoor and Indoor Surveying Tasks

The Simultaneous Localization and Mapping (SLAM) scanner is an easy and portable Light Detection and Ranging (LiDAR) data acquisition device. Its main output is a 3D point cloud covering the scanned scene. Regarding the importance of accuracy in the survey domain, this paper aims to assess the accuracy of two SLAM scanners: the NavVis VLX and the BLK2GO scanner. This assessment is conducted for both outdoor and indoor environments. In this context, two types of reference data were used: the total station (TS) and the static scanner Z+F Imager 5016. To carry out the assessment, four comparisons were tested: cloud-to-cloud, cloud-to-mesh, mesh-to-mesh, and edge detection board assessment. However, the results of the assessments confirmed that the accuracy of indoor SLAM scanner measurements (5 mm) was greater than that of outdoor ones (between 10 mm and 60 mm). Moreover, the comparison of cloud-to-cloud provided the best accuracy regarding direct accuracy measurement without manipulations. Finally, based on the high accuracy, scanning speed, flexibility, and the accuracy differences between tested cases, it was confirmed that SLAM scanners are effective tools for data acquisition.

Application of optical homogeneity detection technology in glass quality control based on visual inspection technology

Abstract Glass is an advanced material with a wide range of applications. Improving the quality of glass products supports and promotes various industries. This paper discusses the streaks affecting the quality of glass products and focuses on implementing optical homogeneity detection technology for glass. Based on the relationship between optical homogeneity and mechanical properties, this detection technology analyzes the causes of streaks in the production process of glass products and deduces the causes for the streak characteristics through the discussion of the working principle of the homogeneity detection technology, the detection device, the detection steps and the use of technology. In this study, visual inspection technology is introduced into the optical homogeneity inspection technology instead of the traditional manual inspection method, which can make the inspection results faster and more accurate and can find a quick and effective solution to the streaks.

The research and development of an IoT device for early detection of fire and explosion risks and monitoring air quality in computer labs

The research and development of an IoT device for early detection of fire and explosion risks and monitoring air quality in computer labs

Design of an electronic device for detection of exhaled gas concentration

Design of an electronic device for detection of exhaled gas concentration

Research on wheat broken rate and impurity rate detection method based on DeepLab-EDA model and system construction

The broken rate and impurity rate of wheat are important indicators for assessing the quality of combine harvester operations. In view of the overlapping, occlusion and dense adhesion between the scattered grains during the operation of the combine harvester, it is difficult to obtain the grain crushing characteristics and impurity mass, which leads to low detection accuracy. In this paper, a method for detecting wheat broken rate and impurity rate based on DeepLab-EDA semantic segmentation model was proposed, and a detection system was built. In the detection system, an image acquisition device was designed and developed based on the principle of electromagnetic vibration, and the deep learning model was deployed in the embedded processor. Through the human–computer interaction interface design, the online processing and analysis of wheat image data and the display of the detection results of broken rate and impurity rate were realized. Comparative experiments with traditional semantic segmentation models showed that the MIoU, MP and MR of the DeepLab-EDA model were 89.41 %, 95.97 % and 94.83 %, respectively, representing improvements of 9.94%, 7.41%, and 7.52% over the baseline model, and indicating a significant enhancement in the accurate identification and segmentation of broken grain and impurities. Based on this, indoor group matching experiments were conducted with three groups of broken rate and impurity rate levels set at 0.5%, 1.5%, and 2.5%, showing the average errors of 7.54% and 6.30% for broken rate and impurity rate detection systems, respectively. Furthermore, the detection device was installed under the grain outlet of the GM80 combine harvester for field experiments, which showed average errors of 13.32% and 9.77% for wheat broken rate and impurity rate, respectively. The effectiveness and accuracy of the wheat broken rate and impurity rate detection system meet the requirements, which can provide a data basis for intelligent control of combine harvester operation parameters by the operator.

Demonstration of microwave single-shot quantum key distribution

Security of modern classical data encryption often relies on computationally hard problems, which can be trivialized with the advent of quantum computers. A potential remedy for this is quantum communication which takes advantage of the laws of quantum physics to provide secure exchange of information. Here, quantum key distribution (QKD) represents a powerful tool, allowing for unconditionally secure quantum communication between remote parties. At the same time, microwave quantum communication is set to play an important role in future quantum networks because of its natural frequency compatibility with superconducting quantum processors and modern near-distance communication standards. To this end, we present an experimental realization of a continuous-variable QKD protocol based on propagating displaced squeezed microwave states. We use superconducting parametric devices for generation and single-shot quadrature detection of these states. We demonstrate unconditional security in our experimental microwave QKD setting. The security performance is shown to be improved by adding finite trusted noise on the preparation side. Our results indicate feasibility of secure microwave quantum communication with the currently available technology in both open-air (up to ~ 80 m) and cryogenic (over 1000 m) conditions.

A handheld electrochemical bacterial sensor based on multifunctional composite hydrogels and DNA biomimetic nanowalls for accurate detection of Porphyromonas gingivalis

Porphyromonas gingivalis (Pg) is not merely one of the important periodontal pathogens, but also exhibits a profound and intimate connection with various systemic diseases, such as cancer, cardiovascular disease, and Alzheimer’s disease. Hence, a handheld electrochemical bacterial sensor (Hebs) is developed for point-of-care testing of Pg in saliva based on an enhanced personal glucose meter platform. In the Hebs, a novel multifunctional composite hydrogel (MFCHgel) is prepared with outstanding conductivity, electrical activity, adhesion and modifiability. In particular, its superior adhesion effectively addresses the inherent issue of electrode-modified material being prone to detachment while ensuring excellent conductivity, which is extremely beneficial for the stability of biosensor. In addition, by assembling DNA biomimetic nanowalls (DBNWs), the surface negative charge and steric hindrance of Pg are enhanced significantly, leading to a remarkable improvement in the electrical impedance response of Pg. Based on their cooperation, the Hebs is capable of effectively detecting Pg within the range of 10 to 1 × 107 CFU/mL, with an impressive limit of detection as low as 6 CFU/mL. Significantly, Hebs exhibits remarkable accuracy in analyzing 40 clinical saliva samples and offers distinct advantages in terms of time consumption and portability as compared to the ELISA kit. This work successfully develops a Hebs for point-of-care testing of Pg, thereby presenting a novel perspective for the advancement of portable bacterial detection devices.

Deep Learning-Based Intelligent Detection Device for Insulation Pull Rod Defects

Deep Learning-Based Intelligent Detection Device for Insulation Pull Rod Defects

A lantern-shaped fluorescent probe based on viologen/polyoxometalate for the detection of Ag+ in beverages and daily necessities

A lantern-shaped viologen/polyoxometalate (POM)-based compound [NiII(MSBP)2(H2O)2]·(β-Mo8O26)·H2O (Ni-POM) (MSBP = 1-(4-Methanesulfonyl-benzyl)-[4,4']bipyridinyl-1-ium) was successfully synthesized by a hydrothermal method for the efficient detection of Ag+. A strong affinity between Ag+ and SO in the viologen component of the Ni-POM structure made them interact, which led to blue fluorescence quenching. In the concentration range of 0.1–4 μM, a strong linear relationship was observed between the Ag+concentration and the fluorescence intensity ratio of Ni-POM, and the limit of detection (LOD) was 20.4 nM. Considering the widespread presence of Ag+ in various water sources, daily necessities and food preservatives, the utilization of Ni-POM for detecting the concentration of Ag+ in real samples (water, daily necessities and beverages) was proved to be highly effective. Moreover, a remarkable recovery rate ranging from 95.70 % to 103.60 % was achieved, indicating that the monitoring results of practical samples were satisfactory. A fluorescent ink based on Ni-POM was designed for the purpose of information confidentiality. More importantly, the hydrogel intelligent device for visual detection of Ag+ was developed, which could realize visual real-time on-site quantitative detection of Ag+ concentration in beverages and daily necessities. Therefore, Ni-POM provides an effective platform for the development of visually quantitative detection of Ag+ in food and daily necessities.

Optical Interferometric Device for Rapid and Specific Detection of Biological Cells.

Here, we report a rapid and accurate optical method for detecting cells from liquid samples in a label-free manner. The working principle of the method is based on the interference of parts of a conical laser beam, coming from a single-mode optical fiber directly, and reflected from a flat glass surface. The glass is functionalized by antibodies against the cells to be detected from the liquid sample. Cells bound to that surface modify the reflected beam, and hence, change the resulting interference pattern, too. By registering and interpreting the variation in the image, the presence of cells from the sample can be detected. As for a demonstration, cell suspensions from a U937 cell line were used in glass chambers functionalized by antibodies (TMG6-5 (mIgG1)) to which the cells specifically bind. The limit of detection (LOD) of the method was also estimated. This proof-of-concept setup offers a cost-effective and easy-to-use way of rapid and specific detection of any type of cells (including pathogens) from suspensions (e.g., body fluids). The possible portability of the device predicts its applicability as a rapid test in clinical diagnostics.