Design and 3D FEM Analysis of a Flexible Piezoelectric Micromechanical Ultrasonic Transducer Based on Sc-Doped AlN Film.

In this paper, a flexible piezoelectric micromachined ultrasonic transducer (PMUT) based on Scandium (Sc)-doped Aluminum Nitride (AlN) film was designed and modeled by the three-dimensional finite element method (3D-FEM). The resonant frequency of 218.1 kHz was reported. It was noticeable that a high effective electromechanical coupling coefficient (k2eff) of 1.45% was obtained when a combination of a flexible PI and a thin Si layer was used as the PMUT supporting structure layer. Compared with a pure Si supporting layer counterpart, the coupling coefficient had been improved by 110.68%. Additionally, the increase of Sc doping concentration in AlN film further enhanced the device electromechanical coupling coefficient and resulted in an improvement for transmitting/receiving sensitivity of the proposed flexible PMUT. When the doping concentration of Sc reached 30%, the emission sensitivity was as large as 1.721 µm/V, which was 2.86 times greater than that of conventional AlN film-based PMUT. The receiving sensitivity was found to be 2.11 V/KPa, which was as high as 1.23 times the performance of an undoped device. Furthermore, the bending simulation result showed that the proposed flexible PMUT device can maintain a good mechanical stability when the bending radius is greater than 1.5 mm. The simulation of sound field characteristics demonstrated that the flexible PMUT based on AlScN could receive stable sound pressure signals under the bending radius of 1.5 cm.

A Novel Transfer Function Based Ring-Down Suppression System for PMUTs.

In this paper, a novel ring-down suppression system based on transfer function is proposed for the first time to suppress the ring-down time and decrease the blind area of PMUTs (Piezoelectric Micromachined Ultrasonic Transducers). This suppression system includes a transfer function and a simple P (proportion) controller, which can reduce the ring-down time without degrading any performances of PMUTs. The transfer function serves as a virtual PMUT device, feeding its output into the P controller; then, the P controller generates a suppression signal to the actual PMUT device. The ring-down time of a 115-kHz PMUT array is demonstrated to be reduced by up to 93% through the suppression system. In addition, the P controller has been experimentally optimized, reducing the blind area of the PMUT array by about 40%. Moreover, a low ring-down PMUTs system design guideline is established, which is practical and straightforward for industrial scenarios. Finally, the system can be easily integrated into ASIC (Application Specific Integrated Circuit).

Rapidly screening of α-glucosidase inhibitors from Dioscorea opposita Thunb. peel based on rGO@Fe3O4 nanocomposites microreactor.

Present study aimed to immobilise the α-glucosidase on suitable supports to construct enzymatic microreactors and their subsequent applicability in efficient inhibitor screening from the Chinese Yam (Dioscorea opposita Thunb.) peel. A type of lamellar and porous composites (rGO@Fe3O4) were synthesised with a facile one-step solvothermal method and employed as carriers to construct enzymatic microreactors for screening α-glucosidase ligand from the Chinese Yam peel in league with the high performance liquid chromatography and mass spectrometry (HPLC-MS). The immobilisation amount of α-glucosidase on rGO@Fe3O4 under the optimised conditions was about 40 µg α-glucosidase/mg carriers. Furthermore, the binding capacities of screened inhibitors, 2,4-dimethoxy-6,7-dihydroxyphenanthrene and batatasin I, were 35.6 and 68.2%, respectively. Hence, considering their high screening efficiency and excellent magnetic separation ability, these as-prepared nanocomposite consisting of rGO and Fe3O4 may be potential supports for the enzyme (such as α-glucosidase) immobilisation for rapid α-glucosidase inhibitors screening from the diverse nature resources.

[Effects of Lidocaine on the Rho/ROCK Signal Transduction of the Posterior Basilar Artery in Rabbit SAH].

OBJECTIVE: To observe the expression of Rho/Rho-associated kinase (ROCK) signaling pathway in the basilar artery and the effect of lidocaine on this signaling pathway after subarachnoid hemorrhage (SAH) in rabbits. METHODS: 24 New Zealand white rabbits were randomly divided into sham operation (sham) group, SAH group, and occipital cisterna lidocaine (CD) group. There were 8 rabbits in each group. Intracisternal injection of non-anticoagulant autologous arterial blood (1 mL/kg) were applied to SAH group and CD group animals to establish SAH model, sham normal saline group was injected with 37 ℃ physiological saline (1 mL/kg); after 30 min, CD group was injected with 0.3 mL 2% lidocaine cisterna, SAH group and sham group were injected with saline. After 72 h, food intake and neurologic function damage were measured. The expressions of Rho associated kinase 2 (ROCK2) and myosin light chain (MLC) and calmodulin (CaM) protein in the basilar artery were measured by Western blot. The ROCK2 and MLC and CaM gene expressions were measured by using real-time quantitative PCR. RESULTS: Compared with sham group, reduced food intake, various degrees of neurological impairment, increased ROCK2 mRNA and protein expressions in basal artery, and decreased MLC and CaM expressions were observed in SAH group and CD group (P<0.05). Compared with the SAH group, there was no statistically significant difference in diet intake and neurological damage in the CD group (P>0.05); the mRNA and protein expressions of ROCK2 in the basilar artery decreased, and the expressions of MLC and CaM increased (P<0.05). CONCLUSION: Intracisternal injection of lidocaine may inhibit the transmission of Rho/ROCK signal in the basilar artery and reduce the basilar artery smooth muscle contraction after SAH.

Underwater drag-reducing effect of superhydrophobic submarine model.

To address the debates on whether superhydrophobic coatings can reduce fluid drag for underwater motions, we have achieved an underwater drag-reducing effect of large superhydrophobic submarine models with a feature size of 3.5 cm × 3.7 cm × 33.0 cm through sailing experiments of submarine models, modified with and without superhydrophobic surface under similar power supply and experimental conditions. The drag reduction rate reached as high as 15%. The fabrication of superhydrophobic coatings on a large area of submarine model surfaces was realized by immobilizing hydrophobic copper particles onto a precross-linked polydimethylsiloxane (PDMS) surface. The pre-cross-linking time was optimized at 20 min to obtain good superhydrophobicity for the underwater drag reduction effect by investigating the effect of pre-cross-linking on surface wettability and water adhesive property. We do believe that superhydrophobic coatings may provide a promising application in the field of drag-reducing of vehicle motions on or under the water surface.

[Prevention Effect of Thymosin-alpha1 Aganist Early Ventilator-associated Pneumonia in Patients with Mechanical Ventilation].

OBJECTIVE: To investigate the preventive effects of thymosin-alpha1 against early ventilator-associated pneumonia (VAP) in the patients with mechanical ventilation. METHODS: Fifty two patients with expectancy of mechanical ventilation over 48 h were divided into routine therapy group (n=26) and thymosin therapy group (n= 26) in random. The patients in routine therapy group were given intensive care unit (ICU) conventional treatment, and the patients in thymosin therapy group were given thymosin treatment additionally (1.6 mg subcutaneous injection, qd X 7 d). The incidence and occurrence time of VAP were observed, and the time of mechanical ventilation and ICU stay were recorded. The levels of CD3+, CD4+, CD4+ /CD8+ T lymphocyte, CD14+ mononuclear cell human leukocyte antigens-DR (CD14+ HLA-DR) and procalcitonin (PCT) were detected before mechanical ventilation and at the 3d and 7th d after mechanical ventilation. RESULTS: The base line including the level of immunologic function had no difference between the two groups (P>0.05). The incidence of VAP in thymosin therapy group was lower than that in routine therapy group, but it was not significant difference (P>0.05). The durations of machine ventilation and ICU stay in thymosin therapy group were shorter than those in routine therapy group (P<0.05). The occurrence time of VAP in thymosin therapy group was significantly later than that in routine therapy group (P<0.05). At the 3rd and 7th d after mechanical ventilation, thymosin therapy group achived higher levels of CD3+, CD4+, CD4+ /CD8+ T lymphocyte and CD14+ HLA-DR than routine therapy group did (P<0.05). CONCLUSION: Thymosinal may be able to improve immunologic function and prevent the incidence of early VAP in the patients with mechanical ventilation.

Multifunctional Co(0.85)Se-Fe(3)O(4) nanocomposites: controlled synthesis and their enhanced performances for efficient hydrogenation of p-nitrophenol and adsorbents.

A new kind of multifunctional Co0.85 Se-Fe3 O4 nanocomposites is synthesized by loading Fe3 O4 nanoparticles (NPs) with a size of about 5 nm on the surface of Co0.85 Se nanosheets under hydrothermal conditions without using any surfactant or structure-directing agents. The Co0.85 Se-Fe3 O4 nanocomposite exhibits remarkable catalytic performance for hydrogenation of p-nitrophenol (4-NP) at room temperature and good adsorption behavior for methylene blue trihydrate in water. This nanocomposite also shows a high specific surface area and magnetic separation capability for recyclable utilization. The enhanced performances both in catalysis and adsorption are better than either individual component of Co0.85 Se nanosheets or Fe3 O4 nanoparticles, demonstrating the possibility for designing new multifunctional nanocomposites with improved performances for catalysis, adsorbents, and other applications.

[The effect of Xuebijing injection on immune regulation in SIRS patients].

OBJECTIVE: To investgate the effect of Xuebijing Injection on immune regulation in patients with systemic inflammatory response syndrome (SIRS). METHODS: 56 SIRS patients admitted to the ICU of Guizhou Provincial Hospital from January 2013 to December 2013 were included in this study. The patients were randomly divided into a control (C) and a treatment (T) group. Patients in C group received routine treatment; while patients in T group received additional Xuebijing Injection 50 mL Bid. The following indicators were recorded and compared between the two groups before and 4 and 7 days after treatments: CD4+, CD8+, CD4+/CD8+, monocytes CD14+/human leukocyte antigen-DR (HLA-DR), score of acute physiology and chronic health evaluation II (APACHE II), heart rate, white blood cells, body temperature, respiration rate, and MODS (7 d after treatment only). RESULTS: No differences were found between the two groups before treatments (P > 0.05). T Group had higher levels of CD4+, CD8, CD4+/CD8+ and monocytes CD14+/HLA-DR than C group at 4 and 7 d after treatments (P < 0.05). T group also had higher levels of improvement in vital indicators compared with C group (P < 0.05). No significant difference in incidence of multiple organ dysfunction syndrome (MODS) was found between the two groups (P > 0.05). CONCLUSION: Xuebijing Injection can regulate immune function of patients with SIRS.

Ablation for malignant liver tumor using high-intensity focused ultrasound and radio-frequency: A meta-analysis.

BACKGROUND: Primary liver cancer is a major health issue, so finding the most effective treatment is vital. OBJECTIVE: The present meta-analysis compares high-intensity focused ultrasound (HIFU) to radiofrequency (RF) ablation for primary liver cancer treatment. METHODS: PubMed, MEDLINE, CNKI, VIP, and Wanfang were used to search for English and Chinese papers. After carefully confirming data completeness and applying inclusion and exclusion criteria, RevMan 5.3 was used to evaluate the included literature. Data analysis utilized a fixed-effects model for heterogeneity between 0.1 and 0.5. RESULTS: The meta-analysis included 304 patients: 119 had HIFU and 185 RF ablation. For primary liver cancer, HIFU and RF ablation were equally efficacious (odds ratio 1.02, 95% confidence interval [0.54, 1.92]). Overall survival, disease-free survival, and complications at 1, 2, and 3 years were not significantly different (odds ratio 0.72, 95% confidence range [0.04, 12.79], P= 0.82). CONCLUSION: The meta-analysis shows no significant difference in efficacy, long-term survival rates, or complication rates between HIFU and RF ablation for primary liver cancer, but more large-scale, high-quality randomized clinical trials are needed to prove their equivalence. Both therapy strategies seem promising, but additional information is needed to determine their respective merits.

Improved Performance of Acoustically Actuated Magnetoelectric Antenna with FeGa/FeGaB Bilayer.

Acoustically actuated magnetoelectric (ME) antennas utilize acoustic wave resonance to complete the process of receiving and transmitting signals, which promotes the development of antenna miniaturization technology. This paper presents a bilayer magnetostrictive/AlN ME laminated antenna. The proposed laminated antenna uses the FeGa/FeGaB bilayer materials as magnetostrictive materials, which combine the advantages of soft magnetic properties of FeGa and the low loss of FeGaB. First, multiphysics modeling and analysis are performed for the proposed ME laminated antenna by finite element method (FEM). The positive/inverse ME effects and the influences of the volume ratio of the FeGa/FeGaB bilayer on the antenna performance are studied. The results show that the output voltage and ME coefficient of the FeGa/FeGaB bilayer magnetostrictive material with a volume ratio of 1:1 are 3.97 times and 195.8% higher than that of the single FeGaB layer, respectively. The eddy current loss is 52.08% lower than that of single-layer FeGa. According to the surface equivalence principle, the far-field radiation process is simulated. The results show that the gain of the ME antenna is 15 dB larger than that of the same-size micro-loop antenna, and the gain of the ME antenna is about -44.9 dB. The improved performance and magnetic tunability of the proposed bilayer magnetostrictive materials make ME antennas excellent candidates for portable devices and implantable medical devices.

Endocytosis efficiency and targeting ability by the cooperation of nanoparticles.

Cooperative wrapping of nanoparticles (NPs) with small sizes is an important pathway for the uptake of NPs by cell membranes. However, the cooperative wrapping efficiency and the effects of NPs' rigidity remain ambiguous. With the aid of computer simulations, we show that the complete wrapping mechanism of cooperative endocytosis is that the aggregation of NPs leads to greater wrapping forces than the single NP case, which triggers the increase of the wrapping degree and in turn further increases the wrapping forces until they are finally fully taken up. The effects of the NP size, initial distance, interaction strength, arrangement and stiffness on cooperative endocytosis were systematically studied. The cooperative wrapping efficiency increases as the NP radius increases. Hexagonal close packed NPs have the highest internalization efficiency. When the interactions are strong, softer NPs exhibit higher endocytosis efficiency. We further propose two strategies by combining NPs with different wrapping properties for targeting applications. By combining two NPs decorated with different types of ligands, the combination NPs can only be fully endocytosed by the cell membrane with two cognate types of receptors and adhere to the normal cell membrane with only one type of receptor. We also design composite NPs using a large NP non-covalently decorated with several small NPs. By harnessing the competition between the ligand-receptor interactions and the excluded volume interactions between the small NPs and the lipid membrane, the composite NPs have targeting ability towards the cancer cell membrane. The design concept of combining NPs with different wrapping properties for drug targeting applications may be very promising in biomedicine.

Correction: Teng et al. Efficacy Assessment of Phage Therapy in Treating Staphylococcus aureus-Induced Mastitis in Mice. Viruses 2022, 14, 620.

In the original publication [...].

Stepped-Tube Backside Cavity Piezoelectric Ultrasound Transducer Based on Sc0.2AI0.8N Thin Films.

This paper presents a novel piezoelectric micromachined ultrasonic transducer (PMUT) with theoretical simulation, fabrication, and testing. Conventional methods using a PCB or an external horn to adjust the PMUT acoustic field angle are limited by the need for transducer size. To address this limitation, the stepped-tube (expanded tube) backside cavity PMUT has been proposed. The stepped-tube PMUT and the tube PMUT devices have the same membrane structure, and the acoustic impedance matching of the PMUT is optimized by modifying the boundary conditions of the back cavity structure. The acoustic comparison experiments show that the average output sound pressure of the stepped-tube backside cavity PMUT has increased by 17%, the half-power-beam-width (θ-3db) has been reduced from 55° to 30° with a reduction of 45%, and the side lobe level signal is reduced from 147 mV to 66 mV. In addition, this work is fabricated on an eight-inch wafer. The process is compatible with standard complementary metal oxide semiconductor (CMOS), conditions are stable, and the cost is controllable, plus it facilitates the batch process. These conclusions suggest that the stepped-tube backside cavity PMUT will bring new, effective, and reliable solutions to ranging applications.

Whole-exome sequencing revealed novel genetic alterations in patients with tetralogy of Fallot.

Background: The most prevalent cyanotic congenital heart disease (CHD) phenotype is tetralogy of Fallot (TOF). Rare genetic variations have been identified as significant risk factors for CHD. Thus, this research sought to identify the pathogenic variations and molecular etiologies of TOF. Methods: This study employed whole-exome sequencing (WES) and Sanger sequencing to identify pathogenic variations in DNA samples from patients with TOF. The pathogenicity of the variations was predicted using an in-silico approach. Results: We enrolled 17 patients with TOF in this study. Among these patients, 14 had mutations in TOF-related genes, including GJB2, TBX15, CTNS, SPINK1, GATA6, PRIMOL, GDF15, SLC17A9, AIFM1, FOXC2, KLF13, ABCA4, CPA6, FKBP10, ASPA, SBF1, HBA2, IGLL1, GNE, and KLHL10. We also gathered WES data from three participants without TOF, who comprised the control group, but no variations were found in the indicated genes. Further analysis showed that the patients with FKBP10 and GNE variants had more serious clinical symptoms. Sanger sequencing confirmed that the two variants were heterozygous in TOF patients. Conclusions: We identified several genetic variants associated with TOF and confirmed that FKBP10 and GNE variants were associated with TOF severity. The findings of this study help researchers and clinicians on genetic counseling with the verification of the potential of WES in detecting TOF and help implement early interventions for patients with TOF.

Miniature Ultrasonic Spatial Localization Module in the Lightweight Interactive.

The advancement of spatial interaction technology has greatly enriched the domain of consumer electronics. Traditional solutions based on optical technologies suffers high power consumption and significant costs, making them less ideal in lightweight implementations. In contrast, ultrasonic solutions stand out due to their lower power consumption and cost-effectiveness, capturing widespread attention and interest. This paper addresses the challenges associated with the application of ultrasound sensors in spatial localization. Traditional ultrasound systems are hindered by blind spots, large physical dimensions, and constrained measurement ranges, limiting their practical applicability. To overcome these limitations, this paper proposes a miniature ultrasonic spatial localization module employing piezoelectric micromechanical ultrasonic transducers (PMUTs). The module is comprised of three devices each with dimension of 1.2 mm × 1.2 mm × 0.5 mm, operating at a frequency of around 180 kHz. This configuration facilitates a comprehensive distance detection range of 0-800 mm within 80° directivity, devoid of blind spot. The error rate and failure range of measurement as well as their relationship with the SNR (signal-to-noise ratio) are also thoroughly investigated. This work heralds a significant enhancement in hand spatial localization capabilities, propelling advancements in acoustic sensor applications of the meta-universe.

Next-generation sequencing technology for the diagnosis of Pneumocystis pneumonia in an immunocompetent female: A case report.

BACKGROUND: Pneumocystis pneumonia (PCP) is a serious fungal infection usually seen in patients with human immunodeficiency virus, and it is more frequently found and has a high fatality rate in immunocompromised people. Surprisingly, it rarely occurs in immunocompetent patients. However, the clinical diagnosis of this pathogen is made more difficult by the difficulty of obtaining accurate microbiological evidence with routine tests. This case reports a PCP patient with normal immune function who was diagnosed through next-generation sequencing (NGS). CASE SUMMARY: A 23-year-old female who had no special disease in the past was admitted to the hospital with a persistent fever and cough. Based on the initial examination results, the patient was diagnosed with bipulmonary pneumonia, and empirical broad-spectrum antibiotic therapy was administered. However, due to the undetermined etiology, the patient's condition continued to worsen. She was transferred to the intensive care unit because of acute respiratory failure. After the diagnosis of Pneumocystis jirovecii infection through NGS in bronchoalveolar lavage fluid and treatment with trimethoprim/sulfamethoxazole and caspofungin, the patient gradually recovered and had a good prognosis. CONCLUSION: This case emphasizes that, for patients with normal immune function the possibility of PCP infection, although rare, cannot be ignored. NGS plays an important role in the diagnosis of refractory interstitial pneumonia and acute respiratory failure.

Development of a colloidal gold immunochromatographic strip with enhanced signal for the detection of bovine parvovirus.

Bovine parvovirus (BPV) is a pathogen responsible for respiratory and digestive tract symptoms in calves and abortion and stillbirth in pregnant cows. In this study, we developed a colloidal gold immunochromatographic (GICG) strip with an enhanced signal for detecting BPV according to the double-antibody sandwich principle and an enzyme-based signal amplification system to amplify the signal. This system utilizes horseradish peroxidase reacting with a substrate solution containing 3,3',5,5'-tetramethylbenzidine and dextran sulfate to obtain insoluble blue products on the test and control lines. We optimized different reaction conditions, including the amount of monoclonal antibodies (mAbs), pH of the colloidal gold solution, coating solution, blocking solution, sample pad treatment solution, antibody concentration in the control line, and antibody concentration in the detection line. The sensitivity of the signal-enhanced GICG strip showed that the minimum amount for detecting BPV was 102 TCID50, 10 times higher than that of the traditional GICG strip. The results of the specificity test showed that the signal-enhanced GICG strip had no cross-reactivity with BRV, BVDV, or BRSV. The results of the repeatability test showed that the coefficient of variation between and within batches was less than 5%, showing good repeatability. Moreover, for validation, PCR and the signal-enhanced GICG strip were used to detect 280 clinical bovine fecal samples. The concordance rate compared with PCR was 99.29%. Hence, the developed strip exhibited high sensitivity and specificity for the detection of BPV. Therefore, this strip could be a rapid, convenient, and effective method for the diagnosis of BPV infection in the field.

A miniaturized transit-time ultrasonic flowmeter based on ScAlN piezoelectric micromachined ultrasonic transducers for small-diameter applications.

Transit-time ultrasonic flowmeters (TTUFs) are among the most widely used devices for flow measurements. However, traditional TTUFs are usually based on a bulk piezoelectric transducer, which limits their application in small-diameter channels. In this paper, we developed a miniaturized TTUF based on scandium-doped aluminum nitride (ScAlN) piezoelectric micromachined ultrasonic transducers (PMUTs). The proposed TTUF contains two PMUT-based transceivers and a π-type channel. The PMUTs contain 13 × 13 square cells with dimensions of 2.8 × 2.8 mm2. To compensate for the acoustic impedance mismatch with liquid, a layer of polyurethane is added to the surface of the PMUTs as a matching layer. The PMUT-based transceivers show good transmitting sensitivity (with 0.94 MPa/V surface pressure) and receiving sensitivity (1.79 mV/kPa) at a frequency of 1 MHz in water. Moreover, the dimensions of the π-type channel are optimized to achieve a measurement sensitivity of 82 ns/(m/s) and a signal-to-noise ratio (SNR) better than 15 dB. Finally, we integrate the fabricated PMUTs into the TDC-GP30 platform. The experimental results show that the developed TTUF provides a wide range of flow measurements from 2 to 300 L/h in a channel of 4 mm diameter, which is smaller than most reported channels. The accuracy and repeatability of the TTUF are within 0.2% and 1%, respectively. The proposed TTUF shows great application potential in industrial applications such as medical and chemical applications.

Nondestructive Wafer Level MEMS Piezoelectric Device Thickness Detection.

This paper introduces a novel nondestructive wafer scale thin film thickness measurement method by detecting the reflected picosecond ultrasonic wave transmitting between different interfacial layers. Unlike other traditional approaches used for thickness inspection, this method is highly efficient in wafer scale, and even works for opaque material. As a demonstration, we took scandium doped aluminum nitride (AlScN) thin film and related piezoelectric stacking layers (e.g. Molybedenum/AlScN/Molybdenum) as the case study to explain the advantages of this approach. In our experiments, a laser with a wavelength of 515 nm was used to first measure the thickness of (1) a single Molybdenum (Mo) electrode layer in the range of 100-300 nm, and (2) a single AlScN piezoelectric layer in the range of 600-1000 nm. Then, (3) the combined stacking layers were measured. Finally, (4) the thickness of a standard piezoelectric composite structure (Mo/AlScN/Mo) was characterized based on the conclusions and derivation extracted from the aforementioned sets of experiments. This type of standard piezoelectric composite has been widely adopted in a variety of Micro-electromechanical systems (MEMS) devices such as the Piezoelectric Micromachined Ultrasonic Transducer (PMUT), the Film Bulk Acoustic Resonator (FBAR), the Surface Acoustic Wave (SAW) and more. A comparison between measurement data from both in-line and off-line (using Scanning Electron Microscope) methods was conducted. The result from such in situ 8-inch wafer scale measurements was in a good agreement with the SEM data.

Development of MEMS Airflow Volumetric Flow Sensing System with Single Piezoelectric Micromachined Ultrasonic Transducer (PMUT) Array.

Compared to conventional ultrasonic flowmeters using multiple transducers, this paper reports, for the first time, an airflow volumetric flowmeter using a signal PMUT array to measure the flow rate in a rectangular pipe. The PMUT around 200 kHz is selected to fit the system requirements. All PMUT elements on this single array are then electrically grouped into transmitter and receiver. In order to minimize the crosstalk signal between transmitter and receiver, a phase shift signal is applied at the transmitter to reduce the amplitude of the crosstalk signal by 87.8%, hence, the resultant high sensing resolution. Based on the analog signal extracted from the single PMUT array, a complete flow sensing system is built by using the cross-correlation method and cosine interpolation, whereby the change in flow rate is reflected by the time of flight difference (dTof) recorded at the receiver. Meanwhile, the acoustic path self-calibration is realized by using multiple echoes. Compared with the previously reported MEMS flowmeters with dual or multiple PMUT devices, this paper proposes a single PMUT array flow sensing system, which is able to measure the flow rate changes up to 4 m3/h. With the implementation of a single device, the problem of ultrasound device/reflector misalignment during system setup is completely eradicated.