Research on data diagnosis method of acoustic array sensor device based on spectrogram

Acoustic array sensor device for partial discharge detection is widely used in power equipment inspection with the advantages of non-contact and precise positioning compared with partial discharge detection methods such as ultrasonic method and pulse current method.However,due to the sensitivity of the acoustic array sensor and the influence of the equipment operation site interference,the acoustic array sensor device for partial discharge type diagnosis by phase resolved partial discharge(PRPD)map might occasionally presents incorrect results,thus affecting the power equipment operation and maintenance strategy.The acoustic array sensor detection device for power equipment developed in this paper applies the array design model of equal-area multi-arm spiral with machine learning fast fourier transform clean(FFT-CLEAN)sound source localization identification algorithm to avoid the interference factors in the noise acquisition system using a single microphone and conventional beam forming algorithm,improves the spatial resolution of the acoustic array sensor device,and proposes an acoustic array sensor device based on the acoustic spectrogram.The analysis and diagnosis method of discharge type of acoustic array sensor device can effectively reduce the system misjudgment caused by factors such as the resolution of the acoustic imaging device and the time domain pulse of the digital signal,and reduce the false alarm rate of the acoustic array sensor device.The proposed method is tested by selecting power cables as the object,and its effectiveness is proved by laboratory verification and field verification.

Research on characteristics of acoustic signal of typical partial discharge models

The pulse current method,acoustic and ultrasonic partial discharge(PD)detection,and voiceprint PD detection are commonly used detection methods for the PD detection of power equipment.To study the characteristics of PD signals of typical discharge models based on the principles of the above three detection methods,an acoustic detection experimental system consisting of a needle-tip model and a surface model was built.Acoustic tests were carried out on needle-tip models with different curvature radii and surface discharge models with different lengths of conductive paste.The experimental results showed that acoustic and ultrasonic PD detection and voiceprint PD detection exhibited different sensitivities to the needle-tip discharge models,and the combination of acoustic and ultrasonic PD and voiceprint PD detection was more beneficial for the comprehensive detection of cable PD signals.Based on voiceprint recognition technology,this study drew FFT(Fast Fourier Transformation)diagrams of different types of PD acoustic signals and analyzed the differences in the ultrasonic signal frequency distribution.The frequency band of the voiceprint PD signal of the needle-tip discharge models was concentrated in the range 17-27 kHz,and the frequency band of the voiceprint PD signal of the conductive paste discharge models was concentrated in the range 20-25 kHz.The measurement of voiceprint PD signals in these frequency bands were strengthened when the PD of a cable was detected on-site,which provides the basis for the use of the cable model for on-site PD detection.

3D spiral channels combined with flexible micro-sieve for high-throughput rare tumor cell enrichment and assay from clinical pleural effusion samples

The sieving and enrichment of rare tumor cells from large-volume pleural effusion(PE)samples is a promising technique for cell-based lung tumor diagnosis and drug tests,which features high throughput and recovery,purification,as well as viability rates of rare target cells as the prerequisites for high sensitivity,specificity,and accuracy of tumor cell analysis.In this paper,we propose a three-dimensional(3 D)sieving method for rare tumor cell enrichment,which effectively eliminates the"dead zones"in traditional two-dimensional(2 D)cell filters with a dimension-raising strategy to satisfy the requirements mentioned above.The prototype device was combined with a funnel-shaped holder,a flexible micropore membrane in the middle,and a3 D spiral fluid channel covered on the membrane as a three-layer ice-creaming cone composite structure.Driven by gravity alone,the device performed as follows:(1)20-fold throughput compared with the 2 D commercial planee hich was up to 20 mL/min for a threefold dilution of whole blood sample;(2)high recovery rates of 84.5%±21%,86%±25%,83%±14%for 100,1000,and 10000 cells/mL,respectively,in 30 mL phosphate buffer saline(PBS)sample,and a 100%positive detection rate in the case of≤5 A549 cells in 1 mL PBS;(3)a typical purification rate of 85.5%±9.1%;and(4)a viability rate of>93%.In the demonstration application,this device effectively enriched rare target cells from large volumes(>25 mL)of clinical pleural effusions.The following results indicated that tumor cells were easy-to-discover in the enriched PE samples,and the proliferation capability of purified cells was(>4.6 times)significantly stronger than that of unprocessed cells in the subsequent 6-day culture.The above evaluation indicates that the proposed easily reproducible method for the effective execution of rare cell enrichments and assays is expected to become a practical technique for clinical cell-based tumor diagnosis.

SERS devices with "hedgehog-like" nanosphere arrays for detection of trace pesticides

The development of surface-enhanced Raman scattering(SERS)devices for detection of trace pesticides has attracted more and more attention.In this work,a large-area self-assembly ap-proach assisted with reactive ion etching(RIE)is proposed for preparing SERS devices consisting of Ag-covered"hedgehog-like"nanosphere arrays(Ag/HLNAs).Such a SERS device has an enhancement factor of 2.79×107,a limit of detection(LOD)up to 10-12 M for Rhodamine 6G(R6G)analytes,and a relative standard deviation(RSD)smaller than 10%,demonstrating high uniformity.Besides,for pesticide detections,the device achieves an LOD of 10-s M for thiram molecules.It indicates that the proposed SERS device has a promising opportunity in detecting toxic organic pesticides.

Directional surface plasmon polariton scattering by single low-index dielectric nanoparticles:simulation and experiment

Directionally scattered surface plasmon polaritons(SPPs)promote the efficiency of plasmonic devices by limiting the energy within a given spatial domain,which is one of the key issues to plasmonic devices.Benefitting from the magnetic response induced in high-index dielectric nanoparticles,unidirectionally scattered SPPs have been achieved via interference between electric and magnetic resonances excited in the particles.Yet,as the magnetic response in low-index dielectric nanoparticles is too weak,the directionally scattered SPPs are hard to detect.In this work,we demonstrate forward scattered SPPs in single low-index polystyrene(PS)nanospheres.We numerically illustrate the excitation mechanism of plasmonic induced electric and magnetic multipole modes,as well as their contributions to forward SPP scattering of single PS nanospheres.We also simulate the SPP scattering field distribution obtaining a forward-to-backward scattering intensity ratio of 50.26:1 with 1μm PS particle.Then the forward scattered SPPs are experimentally visualized by Fourier transforming the real-space plasmonic imaging to k-space imaging.The forward scattered SPPs from low-index dielectric nanoparticles pave the way for SPP direction manipulation by all types of nanomaterials.

piRT-IFC:Physics-informed real-time impedance flow cytometry for the characterization of cellular intrinsic electrical properties

Real-time transformation was important for the practical implementation of impedance flow cytometry.The major obstacle was the time-consuming step of translating raw data to cellular intrinsic electrical properties(e.g.,specific membrane capacitance C_(sm) and cytoplasm conductivityσ_(cyto)).Although optimization strategies such as neural network-aided strategies were recently reported to provide an impressive boost to the translation process,simultaneously achieving high speed,accuracy,and generalization capability is still challenging.To this end,we proposed a fast parallel physical fitting solver that could characterize single cells’C_(sm)andσ_(cyto)within 0.62 ms/cell without any data preacquisition or pretraining requirements.We achieved the 27000-fold acceleration without loss of accuracy compared with the traditional solver.Based on the solver,we implemented physics-informed real-time impedance flow cytometry(piRT-IFC),which was able to characterize up to 100,902 cells’C_(sm) andσ_(cyto)within 50 min in a real-time manner.Compared to the fully connected neural network(FCNN)predictor,the proposed real-time solver showed comparable processing speed but higher accuracy.Furthermore,we used a neutrophil degranulation cell model to represent tasks to test unfamiliar samples without data for pretraining.After being treated with cytochalasin B and N-Formyl-Met-Leu-Phe,HL-60 cells underwent dynamic degranulation processes,and we characterized cell’s C_(sm)andσ_(cyto)using piRT-IFC.Compared to the results from our solver,accuracy loss was observed in the results predicted by the FCNN,revealing the advantages of high speed,accuracy,and generalizability of the proposed piRT-IFC.

From the teapot effect to tap-triggered self-wetting: a 3D self-driving sieve for whole blood filtration

Achieving passive microparticle filtration with micropore membranes is challenging due to the capillary pinning effect of the membranes.Inspired by the teapot effect that occurs when liquid(tea)is poured from a teapot spout,we proposed a tap-triggered self-wetting strategy and utilized the method with a 3D sieve to flter rare cells.First,a 3D-printed polymer tap-trigger microstructure was implemented.As a result,the 3μm micropore membrane gating threshold(the pressure needed to open the micropores)was lowered from above 3000 to 80 Pa by the tap-trigger microstructure that facilated the liquid leakage and spreading to self-wet more membrane area in a positive feedback loop.Then,we implemented a 3D cone-shaped cell sieve with tap-trigger microstructures.Driven by gravity,the sieve performed at a high throughput above 20 mL/min(DPBS),while the micropore size and porosity were 3μm and 14.1%,respectively.We further filtered leukocytes from whole blood samples with the proposed new 3D sieve,and the method was compared with the traditional method of leukocyte isolation by chemically removing red blood cells.The device exhibited comparable leukocyte purity but a higher platelet removal rate and lower leukocyte simulation level,facilitating downstream single-cell analysis.The key results indicated that the tap-triggered self-wetting strategy could significantly improve the performance of passive microparticle filtration.

Si nanowire Bio-FET for electrical and label-free detection of cancer cell-derived exosomes

Exosomes are highly important in clinical diagnosis due to their high homology with their parental cells.However,conventional exosome detection methods still face the challenges of expensive equipment,low sensitivity,and complex procedures.Field effect transistors(FETs)are not only the most essential electronic component in the modern microelectronics industry but also show great potential for biomolecule detection owing to the advantages of rapid response,high sensitivity,and label-free detection.In this study,we proposed a Si nanowire field-effect transistor(Si-NW Bio-FET)device chemically modified with specific antibodies for the electrical and label-free detection of exosomes.The Si-NW FETs were fabricated by standard microelectronic processes with 45 nm width nanowires and packaged in a polydimethylsiloxane(PDMS)microfluidic channel.The nanowires were further modified with the specific CD63 antibody to form a Si-NW Bio-FET.The use of the developed Si-NW Bio-FET for the electrical and labelfree detection of exosomes was successfully demonstrated with a limit of detection(LOD)of 2159 particles/mL.In contrast to other technologies,in this study,Si-NW Bio-FET provides a unique strategy for directly quantifying and realtime detecting exosomes without labeling,indicating its potential as a tool for the early diagnosis of cancer.

Theoretical and experimental analysis of second order Bragg resonance of 45° TFG and its fiber laser application

We report the observation of second order Bragg resonance(2 nd-OBG) produced by tilted fiber gratings(TFGs) fabricated using phase mask UV inscription.The theoretical analysis has revealed that the generation of high order Bragg resonance of gratings is induced by a square-shape refractive index profile,which is caused by over-saturated UV exposure.In the experiment,we have studied the TFGs with different tilt angles under over-saturated UV exposure,in which all gratings have showed the 2 nd-OBR,and the larger tilt angle of the grating has the stronger 2 nd-OBR.When the tilt angle of the grating is-45°,the Bragg resonance exhibits very strong polarization dependence,because the 2 nd-OBR wavelength is located within the polarizing bandwidth of 45° TFG.Finally,we have demonstrated an erbium-doped fiber laser with> 99.9% degree of polarization,and,by applying mechanical stretching on the grating,a wavelength tunable laser output has been achieved.The output laser shows ~0.2 dB amplitude variation within 1 h continuous monitoring of the laser.