Wendong Zhang

Chongqing Normal University | CNU · College of Chemistry

This paper delves into enhancing the performance of ScAlN-based Piezoelectric Micromachined Ultrasonic Transducers (PMUTs) through the implementation of Polydimethylsiloxane (PDMS) acoustic lenses. The PMUT, encapsulated in PDMS, underwent thorough characterization through the utilization of an industry-standard hydrophone calibration instrument. T...

The exploration of ocean depend heavily on effective underwater communication. There is significant promise in the study and development of high-performance sensors tailored specifically for underwater communications. This work presents a high-performance sensor utilizing a scandium-doped aluminum nitride (Sc <sub xmlns:mml="http://www.w3.org/1998/...

Purpose Human-induced marine environmental noise, such as commercial shipping and seismic exploration, is concentrated in the low-frequency range. Meanwhile, low-frequency sound signals can achieve long-distance propagation in water. To meet the requirements of long-distance underwater detection and communication, this paper aims to propose an micr...

Real-time DOA (direction of arrival) estimation of surface or underwater targets is of great significance to the research of marine environment and national security protection. When conducting real-time DOA estimation of underwater targets, it can be difficult to extract the prior characteristics of noise due to the complexity and variability of t...

The miniaturization of low-frequency marine underwater acoustic detection systems presents new requirements for 3-D vector hydrophones. Inspired by fish lateral lines, we have introduced a biomimetic 3-D vector hydrophone. It features a microstructure with a monolithically integrated four-beam central block and cilium, capable of detecting underwat...

For the issue of significant noise in the collected bearing fault signals, a new bearing fault diagnosis model based on mutual mapping of signals and images (MMSI) and sparse representation (SR) denoising is proposed. Firstly, the fault signal is divided into several segments with the same number of sampling points, and then arrange these segments...

This paper presents the design and development of a high-resolution 3D ultrasound imaging system based on a 1 × 256 piezoelectric ring array, achieving an accuracy of 0.1 mm in both ascending and descending modes. The system achieves an imaging spatial resolution of approximately 0.78 mm. A 256 × 32 cylindrical sensor array and a digital phantom of...

Ultrasound is a powerful and versatile technology that has been applied extensively in medicine and scientific research. The development of miniature underwater robots focuses on achieving specific tasks, such as surveys and inspections in confined spaces. However, traditional sonar has limited use in micro underwater robots due to its large size a...

The main frequency band of the radiated signals from ships is 20-500Hz, and also the main working frequency band of the Micro-Electro-Mechanical-System ( MEMS ) vector hydrophone. To improve sensitivity in this frequency band, this paper presents a nested package structure, which encapsulates the sensitive sections of the vector hydrophone with a m...

In this paper, we propose an improved bandwidth matching layer using boron nitride/polydimethylsiloxane (BN/PDMS) 0-3 composites to achieve superior electrical insulation and transmission performance for underwater capacitive micromachined ultrasonic transducer (CMUT) sensor. This innovation addresses the limitations of traditional quarter-waveleng...

Heart sound auscultation is the most important technique physicians use to examine cardiovascular diseases. Doctors use their clinical experience combined with listening to the patient’s first heart sound (S1), second heart sound (S2), and heart murmurs during auscultation to conduct preliminary screening for cardiovascular diseases. However, docto...

A pulse‐driven electrochemical synaptic transistor for supersensitive and ultrafast biosensor is proposed. image

This article investigates a robust path-following control problem of multiple autonomous vehicles along an implicit elliptical curve. At the kinematic level, by formulating a novel coordinated error in terms of projective arc length instead of relative distance, a new distributed guidance law is developed for multiple vehicles evolving along a geom...

A novel breast ultrasound tomography system based on a circular array of capacitive micromechanical ultrasound transducers (CMUT) has broad application prospects. However, the images produced by this system are not suitable as input for the training phase of the super-resolution (SR) reconstruction algorithm. To solve the problem, this paper propos...

High sensitivity and fast response are the figures of merit for benchmarking commercial sensors. Due to the advantages of intrinsic signal amplification, bionic ability, and mechanical flexibility, electrochemical transistors (ECTs) have recently gained increasing popularity in constructing various sensors. In the current work, we have proposed a p...

Coordinated enclosing of quadrotors for a ground moving-target is a promising enabler for exploring, self-localizing as well as autonomously navigating under challenging environments. For this purpose, this article addresses a robust coordinated target encircling control problem of networked quadrotors without the reliance on target speed and accel...

For the bearing fault diagnosis in small sample cases, a new model for signal denoising and entropy feature fusion (EFF) based on the wild horse optimizer (WHO) optimized variational mode decomposition (VMD) and correlation coefficient weight threshold (CCWT) is proposed (WHO–VMD–CCWT–EFF). For signal denoising, we first take the power spectrum ent...

Breast cancer histopathological image automatic classification can reduce pathologists workload and provide accurate diagnosis. However, one challenge is that empirical datasets are usually imbalanced, resulting in poorer classification quality compared with conventional methods based on balanced datasets. The recently proposed bilateral branch net...

The complex and variable ocean environment introduces complex noise to the signal received by microelectromechanical systems (MEMS) vector hydrophones, which seriously affects target location. To improve the detection efficiency and broaden the application range of vector hydrophone, this paper proposed a novel modified Wavelet packet de-noising me...

This paper investigates a novel GPS-free collaborative elliptical circumnavigation control for multiple non-holonomic vehicles, where two realistic issues — achieving a higher efficiency observation and saving the energy expenditures during cooperation are involved. By defining a novel coordinated error relative to neighboring arc length, under the...

In this work, capacitive micro-machined ultrasonic transducers (CMUTs) were developed into comb-like shapes, to make these comb-like shaped structures work for sensing in-plane vibrations of ultrasonic guided waves. On this basis, an analytical small-signal model, which is mainly a combination of the forced vibration theory and the simplified paral...

In this work, the fabrication process and the gas sensing performance toward n-butanol of urchin-like Au decorated SnO2/Fe2O3 (Au at SnO2/Fe2O3 microspheres were presented in detail. The hierarchical SnO2/Fe2O3 structure was constructed by using Fe2O3 microspheres as a precursor and combining with in-suit growth of SnO2 micropillars on their surfac...

Photoacoustic sensor has become a research hotspot in the field of acoustic sensing in recent years due to its high sensitivity and anti-electromagnetic interference. A novel high-Q grooved silica waveguide acoustic sensor (GSWAS) is proposed, which is etched and filled the Polydimethylsiloxane (PDMS) above the waveguide coupling region. The Q fact...

Purpose This paper aims to solve the problem that strong noise interference seriously affects the direction of arrival (DOA) estimation in complex underwater acoustic environment. In this paper, a combined noise reduction algorithm and micro-electro-mechanical system (MEMS) vector hydrophone DOA estimation algorithm based on singular value decompos...

dots (QDs) modified MOF-derived hollow In2O3 (WS2 QDs@In2O3) heterostructure were documented. The proposed gas sensor based on WS2 QDs@In2O3 hollow hexagonal prisms was simple, sensitive, cost-effective and worked at room temperature (25 ± 2 ◦C). The response value of 3 wt% WS2 QDs@In2O3 (W3In) towards 100 ppm NO2 could reach to 2034, which was an...

Because of its adaptive interfacial property, soft sensors/actuators can be used to perform more delicate tasks than their rigid counterparts. However, plant epidermis with a waxy cuticle layer challenges stable and high-fidelity non-invasive electrophysiology since the conventional electrodes are invasive, easily detached from plants, and require...

The design of a highly effective isopropanol gas sensor with high response and trace detection capability is extremely important for environmental surveillance and human health. Here, novel flower-like PtOx@ZnO/In2O3 hollow microspheres were prepared by a three-step approach. The hollow structure was composed of an In2O3 shell inside and layered Zn...

Ship noise observation is of great significance to marine environment research and national defense security. Acoustic stealth technology makes a variety of ship noise significantly reduced, which is a new challenge for marine noise monitoring. However, there are few high spatial gain detection methods for low-noise ship monitoring. Therefore, a hi...

With advances in new materials and technologies, there has been increasing research focused on flexible sensors. However, in most flexible pressure sensors made using new materials, it is challenging to achieve high detection sensitivity across a wide pressure range. Although traditional silicon-based sensors have good performance, they are not for...

Existing cooperative enclosing outcomes are primarily conducted relying on continuous transmission flow among agents, and transient specifications are not explicitly incorporated into the design, which may consume a large amount of communication resources and violate the preset transient constraints. To address abovementioned issues, by resorting t...

Vector hydrophone is the core equipment of underwater acoustic detection. Aiming at the problem of low sensitivity and short detection distance of existing vector hydrophone. In this paper, a hollow mushroom-like cilia sensitive structure is designed to optimize the hydrophone sensitive unit. The optimal size of the hollow mushroom-like cilia MEMS...

SnS2/ZnS microflower structures were synthesized by one-step hydrothermal method. The microflower structures with different components were obtained after calcinating SnS2/ZnS in air atmosphere. The influence of calcination temperature on the components and gas-sensing properties of microflower structures was investigated by X-ray diffractometry (X...

In light of a need for low-frequency, high sensitivity and broadband cardiac murmur signal detection, the present work puts forward an integrated MEMS-based heart sound sensor with a hollow concave ciliary micro-structure. The advantages of a hollow MEMS structure, in contrast to planar ciliated micro-structures, are that it reduces the ciliated ma...

Marine acoustic sensors can detect underwater acoustic information. The cilium micro-electro-mechanical system (MEMS) vector hydrophone (CVH) is the core component of the ocean noise measurement system. The performance of the CVH, especially its self-noise, has received widespread attention. In this paper, we propose a solution to improve the perfo...

It is well known that acoustic emission (AE) signals, generated by external impacts or damages such as crack initiation, mainly propagate in the form of Lamb waves in plate-like structures. In this work, MEMS-based resonant capacitive micro-machined ultrasonic transducers (CMUTs), which are designed for sensing out-of-plane displacements, have been...

In the past two decades, capacitive micro-machined ultrasonic transducers (CMUTs) have been greatly explored for applications in structural health monitoring (SHM), however, relevant theories about their broadband sense have not been investigated systematically. Therefore, the broadband CMUTs have been specifically developed from the aspects of the...

A slot microring resonator acoustic sensor (MRAS) using the PDMS package was proposed to achieve ultra-high sensitivity acoustic detection. The acoustic detection principle of the sensor is analyzed theoretically, the structural parameters are optimized and the performance of the sensor is verified by simulation. The simulation results show that th...

Graphene nanoflakes (GNFs), with intriguing zigzag edge magnetism, have great potential for the application in high-speed and low-power nanoelectronics and spintronics. However, scattering from edge defects can substantially degrade this novel edge magnetism. Precisely controlled growth of GNFs with zigzag edges on dielectric substrates to suppress...

The study of impedance matching between a transducer and its working medium is an important part of acoustic transducer design. The traditional quarter wavelength matching (Q-matching) scheme is not suitable for broadband capacitive micromachined ultrasonic transducers. To mitigate this issue, a 0–3 composite broadband matching layer based on polyd...

As a widely clinical detection method, ultrasonography (US) has been applied to the diagnosis of breast cancer. In this paper, the multi-element synthetic aperture focusing (M-SAF) is applied to the ring array of breast ultrasonography (US) imaging, which addresses the problem of low imaging quality due to the single active element for each emissio...

In order to improve the imaging quality of capacitive micromachined ultrasonic transducer (CMUT) sparse array, the authors propose an imaging strategy combining multi-element synthetic transmit aperture (MSTA) imaging mode and compressed sensing (CS) framework. The imaging strategy consists of four steps: First, use the genetic algorithm (GA) to sp...

With the rapid development and wide application of Micro-Electro-Mechanical System (MEMS) vector hydrophones, it is of higher requirement for the estimation method of direction of arrival (DOA) for a single vector hydrophone in complex environments. Although many classical methods for DOA estimation have been proposed in this field, the DOA estimat...

Photocatalytic CO2 reduction is mainly inspired by natural photosynthesis, which could convert CO2 into high value-added fuels or chemicals through the role of catalysts. However, the photocatalysis efficiency of the currently developed catalysts is far from meeting the actual needs due to the low efficiency of charge separation and energy transfer...

To acquire high-quality electrocardiogram (ECG) signals, traditional Ag/AgCl wet electrodes used together with conductive gel can effectively reduce electrode–skin interface impedance (EII) in a short term. However, their weaknesses of poor flexibility and instability can no longer meet the long-term monitoring requirements of intelligent wearable...

MEMS ciliary vector hydrophone is used for underwater low-frequency acoustic signal testing, but it is limited by mutual inhibition of bandwidth and sensitivity. A crossed-circle bionic vector hydrophone is proposed in this paper. It uses two circular structures to increase receiving area of sound waves and improve sensitivity. At the same time, it...

Triboelectric Hydrogel Sensor Networks In article number 2204803, Hulin Zhang, Jun Chen, and co‐workers construct a body area sensor network based on edible triboelectric hydrogel sensors, which can realize the recognition of multiple motion patterns of infants with the assistance of deep learning algorithms. Moreover, an application is also develo...

The biomedical acoustic signal plays an important role in clinical non-invasive diagnosis. In view of the deficiencies in early diagnosis of cardiovascular diseases, acoustic properties of S1 and S2 heart sounds are utilized. In this paper, we propose an integrated concave cilium MEMS heart sound sensor. The concave structure enlarges the area for...

Morphology control and noble-metal modification have become effective ways to improve the gas sensing performances of mixed-metal-oxide sensors. In this study, ZnSnO3 nanocube structures with different morphologies were synthesized via combining NaOH-assisted dissolution and a calcination process, and they were then modified with various amounts of...

Infants are physically vulnerable and cannot express their feelings. Continuous monitoring and measuring the biomechanical pressure to which an infant body is exposed remains critical to avoid infant injury and illness. Here, a body area sensor network comprising edible triboelectric hydrogel sensors for all‐around infant motion monitoring is repor...

An acoustic sensor packaged with polydimethylsiloxane (PDMS) film sandwich structure is proposed in this paper. The sensor uses a flat glass with a square hole in the middle as the substrate structure. The cavity length of the microfiber knot resonator (MKR) is significantly changed by the applied acoustic pressure, which is ultimately manifested a...

Although computer-aided diagnosis (CAD) have shown excellent performance in Breast cancer (BC) histopathological image, it commonly requires a high-level network, and the recognition efficiency is frequently unsatisfied due to the complex structure of histopathological image. In this study, a ten-layers convolutional neural network (CNN) model call...

Breast cancer is regarded as the leading killer of women today. The early diagnosis and treatment of breast cancer is the key to improving the survival rate of patients. A method of breast cancer histopathological images recognition based on deep semantic features and gray level co-occurrence matrix (GLCM) features is proposed in this paper. Taking...

A novel hydrazine electrochemical sensor with superior sensing capabilities was fabricated by using electrodepositing gold nanoparticles (AuNPs) on the surface of MIL-53 (Fe, Ni) MOFs–derived nanostructures on nickel foam (NF) supporter by solvothermal method. The crystal phase, morphology structure, surface elemental composition and chemical state...

Pathological examination is the gold standard for breast cancer diagnosis. The recognition of histopathological images of breast cancer has attracted a lot of attention in the field of medical image processing. In this paper, on the base of the Bioimaging 2015 dataset, a two-stage nuclei segmentation strategy, that is, a method of watershed segment...

In this paper, a mixed sources dimension reduction Multiple Signal Classification (MUSIC) localization algorithm suitable for Micro-Electro-Mechanical System (MEMS) vector hydrophone linear arrays is proposed, which reduces the two-dimensional search to one-dimensional local search. Firstly, the Lagrangian function is constructed by quadratic optim...

Development of highly sensitive toluene gas sensor is desirable but challenging for both indoor air quality monitoring and medical diagnosis. Herein, we proposed to design Au nanoparticles (NPs) decorated MOF-derived NiO/In2O3 hollow microspheres as efficient sensing materials for toluene detection. Benefiting from the structural merits and synerge...

The establishment of vascularization is the basic prerequisite for the survival and functionalization of three-dimensional (3 D) tissue-engineered constructs. The application of hydrogel to tissue regeneration has promoted the research and development of regenerative medicine. In this study, we fabricated the composite scaffold composed of gelatin...

Based on the high sensitivity and miniaturization advantages of MEMS vector hydrophone, we proposed and designed a monolithic integrated micro-array vector hydrophone composed of multiple sensor units. The theoretical model shows that the micro-array can improve the structural sensitivity and output signal-to-noise ratio while eliminating the probl...

Back Cover: In article number 2100643 by Shengbo Sang and co‐workers, a paper‐based sensing array with layered structure and high sensitivity is prepared by using a writing method which is applied to graphic pressure sensing and distance position detection. Because many scenarios require a safe distance to be maintained, particularly under the infl...

A self-contained MEMS vector hydrophone with a scalar–vector integrated design is proposed in this paper. Compared with traditional MEMS vector hydrophones, this design solves the problem of ambiguity in the port and starboard during orientation, and also realizes the self-contained storage of acoustic signals. First, the sensor principle and struc...

Capacitive micromachined ultrasound transducers (CMUTs) have broad application prospects in medical imaging, flow monitoring, and nondestructive testing. CMUT arrays are limited by their fabrication process, which seriously restricts their further development and application. In this paper, a vacuum-sealed device for medical applications is introdu...

The exploration of marine resources has become an essential part of the development of marine strategies of various countries. MEMS vector hydrophone has great application value in the exploration of marine resources. However, existing MEMS vector hydrophones have a narrow frequency bandwidth and are based on rigid substrates, which are not easy to...

Ultrasound computed tomography (USCT) has become a useful means of breast cancer imaging detection. In this paper, a novel breast ultrasound tomography system based on capacitive micromachined ultrasonic transducer (CMUT) linear arrays is built. Implementation method of parallel beam filtered back-projection algorithm in the background of USCT is d...

Detecting low-frequency underwater acoustic signals can be a challenge for marine applications. Inspired by the notably strong response of the auditory organs of pectis jellyfish to ultralow frequencies, a kind of otolith-inspired vector hydrophone (OVH) is developed, enabled by hollow buoyant spheres atop cilia. Full parametric analysis is perform...

Hydrophones are one of the main sensors for underwater acoustic signal detection, and their positioning accuracy is closely related to their sensitivity. However, in practice, hydrophones need to work in different depths of water environment. The ciliated MEMS vector hydrophone has a four-beam structure and has a certain anti-interference ability a...

Aiming at the low sensitivity of traditional stethoscope and the application value of electronic stethoscope in the early diagnosis of cardiovascular diseases, in this paper,a bionic electronic stethoscopes based on MEMS technology is designed. The feasibility of micro-structure of MEMS electronic sensor is verified by theoretical analysis and fini...

The Sn doped BiOCl (BOC-Sn) nanosheets photocatalyst was fabricated by a one-step chemical precipitate method using BiCl3 and SnCl4•5H2O as precursors. The as-fabricated BOC-Sn was applied to the photocatalytic purification of toluene. The microstructures and physicochemical properties of the samples were systematically characterized by XRD, SEM, T...

As an emerging cancer treatment strategy, photothermal therapy (PTT) is precise, controllable, minimally invasive, low cost and less toxic side effects, thus photothermal transduction agents have been extensively investigated in recent years. Noble metal nanomaterials with unique localized surface plasmon resonance (LSPR) effects are particularly s...

Capacitive micromachined ultrasonic transducers (CMUTs) have been indispensable owing to their resonance characteristics in the MHz frequency range. However, the inferior pressure sensitivity and linearity of traditional CMUTs themselves cannot meet the actual demands of micro-pressure measurements. In this paper, two novel CMUTs are proposed for t...

In order to meet the requirements of having a small structure, a wide frequency band, and high sensitivity for acoustic signal measurement, an acoustic sensor based on a silicon-based grooved microring resonator is proposed. In this paper, the effective refractive index method and the finite element method are used to analyze the optical characteri...

Paper-based flexible pressure sensors have received extensive attention owing to their recoverability and accessibility. In this study, we proposed a graphical pressure sensor array with multilayered structure. A simple writing method was adopted to realize the adsorption of sensitive materials on the fiber structure of cellulose paper. Pressure se...

Silicon nano-film is essential for the rapidly developing fields of nanoscience and flexible electronics, due to its compatibility with the CMOS process. Viscoelastic PDMS material can adhere to Si, SiO2, and other materials via intermolecular force and play a key role in flexible electronic devices. Researchers have studied many methods of transfe...