With the growing global demand for energy,deep underground salt caverns are emerging as a potential solution for large-scale energy storage.In this study,multistage cyclic loading tests were conducted on rock salt at ...With the growing global demand for energy,deep underground salt caverns are emerging as a potential solution for large-scale energy storage.In this study,multistage cyclic loading tests were conducted on rock salt at different temperatures in combination with real-time acoustic emission(AE)monitoring.The results show that the cumulative AE count increases stepwise with increasing cyclic stress.The peak frequency is concentrated primarily in the medium-frequency range,exhibiting a band distribution across low-,medium-,and high-frequency ranges.As the temperature increases,the proportion of low-frequency signals decreases from 14.32%to 5.76%,whereas the proportion of medium-frequency signals increases from 85.48%to 94.1%.The proportion of high-frequency signals remains relatively constant between 0.1%and 0.2%.The amplitude-count relationship of the AE signals demonstrates a strong negative power-law correlation.Furthermore,with increasing temperature,the negative power-law exponent of the amplitude gradually decreases,with the b value decreasing from 1.096 to 0.837 and the a value decreasing from 7.4871 to 6.6982.Under all four temperature conditions,the dominant failure mode in rock salt is tensile cracking.However,as the temperature increases,the proportion of tensile cracks decreases from 88.59%to 75.12%,whereas the proportion of shear cracks at 80℃is nearly double that at 20℃.This finding indicates that as the temperature increases,the ductility of the material increases,and the crack propagation mode shifts from tensile to shear.This research provides valuable insights for the design and stability assessment of salt cavern reservoirs for deep underground energy storage systems.展开更多
To investigate the long-term stability of soft-hard interbedded rock masses with initial damage induced by earthquakes and periodic drying and wetting,this study prepared samples with different initial damage through ...To investigate the long-term stability of soft-hard interbedded rock masses with initial damage induced by earthquakes and periodic drying and wetting,this study prepared samples with different initial damage through cyclic loading and unloading(CLU)experiments followed by cyclic drying and wetting(CDW)experiments,and finally conducted creep experiments.The study analyzed the effects of initial damage on creep mechanical behavior,crack evolution,and explored failure precursor information,revealing the damage failure mechanisms.The results show that the structural characteristics of the rock mass control its macroscopic failure mode.Initial damage promotes microcrack development,influences the fracture mode,and increases the proportion of high-frequency(200−280 kHz)acoustic emission events during creep.Meanwhile,initial damage exacerbates creep characteristics,increasing the creep rate,shortening total creep failure time,and reducing long-term strength.The damage failure is attributed to:the generation of internal cracks and pores in the rock caused by CLU;mineral hydrolysis and expansion-contraction due to CDW,resulting in weakened intergranular cementation;and full development of cracks and pores under creep stress.Additionally,the deformation difference coefficient and the coefficient of variation of RA/AF values can serve as precursor indicators for creep failure.展开更多
To enhance speech emotion recognition capability,this study constructs a speech emotion recognition model integrating the adaptive acoustic mixup(AAM)and improved coordinate and shuffle attention(ICASA)methods.The AAM...To enhance speech emotion recognition capability,this study constructs a speech emotion recognition model integrating the adaptive acoustic mixup(AAM)and improved coordinate and shuffle attention(ICASA)methods.The AAM method optimizes data augmentation by combining a sample selection strategy and dynamic interpolation coefficients,thus enabling information fusion of speech data with different emotions at the acoustic level.The ICASA method enhances feature extraction capability through dynamic fusion of the improved coordinate attention(ICA)and shuffle attention(SA)techniques.The ICA technique reduces computational overhead by employing depth-separable convolution and an h-swish activation function and captures long-range dependencies of multi-scale time-frequency features using the attention weights.The SA technique promotes feature interaction through channel shuffling,which helps the model learn richer and more discriminative emotional features.Experimental results demonstrate that,compared to the baseline model,the proposed model improves the weighted accuracy by 5.42%and 4.54%,and the unweighted accuracy by 3.37%and 3.85%on the IEMOCAP and RAVDESS datasets,respectively.These improvements were confirmed to be statistically significant by independent samples t-tests,further supporting the practical reliability and applicability of the proposed model in real-world emotion-aware speech systems.展开更多
The tire acoustic cavity resonance(TACR)noise is a significant source of the structure-borne noise inside a vehicle in the low-frequency range.This paper studies the noise dissipation effect of porous materials in red...The tire acoustic cavity resonance(TACR)noise is a significant source of the structure-borne noise inside a vehicle in the low-frequency range.This paper studies the noise dissipation effect of porous materials in reducing the TACR noise,an attempt to clarify the acoustic reduction mechanism and improve the accompanying vehicle interior noise level.A numerical model of a simplified tire cavity with rigid boundaries and acoustic excitation is established and further validated by the experiment.The effects of porous parameters on TACR frequency and sound pressure are then investigated and compared.The result reveals that the most influential material parameters are the porosity and material volume.It is also shown that the effectiveness of porous material in the mitigation of noise originates from the curliness of the material,which results in much larger acoustic impedance near the excitation position.Therefore,the sound absorption performance of the cavity attached with porous material proves to be excellent compared to that of the porous material itself.For further studying the damping effects of structural coupling,the flexible boundary of the tire tread is introduced.The results show that the porosity,material volume and structural loss factor of the tread all play important roles in reducing TACR noise.展开更多
We investigate the null tests of cosmic accelerated expansion by using the baryon acoustic oscillation(BAO)data measured by the dark energy spectroscopic instrument(DESI)and reconstruct the dimensionless Hubble parame...We investigate the null tests of cosmic accelerated expansion by using the baryon acoustic oscillation(BAO)data measured by the dark energy spectroscopic instrument(DESI)and reconstruct the dimensionless Hubble parameter E(z)from the DESI BAO Alcock-Paczynski(AP)data using Gaussian process to perform the null test.We find strong evidence of accelerated expansion from the DESI BAO AP data.By reconstructing the deceleration parameter q(z) from the DESI BAO AP data,we find that accelerated expansion persisted until z■0.7 with a 99.7%confidence level.Additionally,to provide insights into the Hubble tension problem,we propose combining the reconstructed E(z) with D_(H)/r_(d) data to derive a model-independent result r_(d)h=99.8±3.1 Mpc.This result is consistent with measurements from cosmic microwave background(CMB)anisotropies using the ΛCDM model.We also propose a model-independent method for reconstructing the comoving angular diameter distance D_(M)(z) from the distance modulus μ,using SNe Ia data and combining this result with DESI BAO data of D_(M)/r_(d) to constrain the value of r_(d).We find that the value of r_(d),derived from this model-independent method,is smaller than that obtained from CMB measurements,with a significant discrepancy of at least 4.17σ.All the conclusions drawn in this paper are independent of cosmological models and gravitational theories.展开更多
In the field of rock engineering,the influence of water is a dynamic process that exhibits varying effects over time and across different locations.To further understand how water influences the mechanical properties ...In the field of rock engineering,the influence of water is a dynamic process that exhibits varying effects over time and across different locations.To further understand how water influences the mechanical properties and acoustic emission(AE)behavior of rocks,this study conducted uniaxial compression experiments on sandstones with varying degrees of wetting under both natural conditions and water-chemical environments.In addition,the study combined AE equipment with digital image correlation(DIC)to monitor the entire failure process.Using the sliding window algorithm,the variation in the variance of AE characteristic parameters during the process of sandstone loading to failure is analyzed from the perspective of critical slowing down.This analysis enables the effective identification of the early warning signal before failure.The experimental findings suggest that an increase in wetting height results in a gradual decrease in peak stress,accompanied by a concomitant increase in the percentage of shear cracks.The characteristic parameters,including energy,amplitude,and ringing count,all exhibit critical slowing phenomena.The waveform of AE characteristic parameters of the same sample is similar,and the mutation time of the precursor signal is roughly the same.All signals appear in the irreversible plastic deformation stage of microcrack initiation.The integration of critical slowing down theory and the b-value early warning method facilitates a more comprehensive evaluation of the stability of rock mass,thereby significantly enhancing the efficiency and safety of disaster prevention measures.展开更多
During deep coal mining,an instability failure of coal usually occurs under the combined effect of initial damage and triaxial cyclic loading and unloading(TCLU).Therefore,this study investigated the impact of initial...During deep coal mining,an instability failure of coal usually occurs under the combined effect of initial damage and triaxial cyclic loading and unloading(TCLU).Therefore,this study investigated the impact of initial damage on mechanical behavior and acoustic emission(AE)characteristics of coal under TCLU.Initial damage variables(IDVs)of coal specimens were quantified using preloading,followed by TCLU experiments to assess the deformation,energy distribution,and fracture development.The results revealed that the increase in IDVs significantly reduced the structural integrity of coal specimens,increased the cumulative irreversible strain,and enhanced the dissipated energy owing to microfracture expansion.Moreover,AE monitoring showed earlier activation of fractures and a higher occurrence of large-scale rupture events of coal specimens with high IDVs,which correlated with decreasing AE b values(reflecting the different scales of fracture within specimens)and increasing S values(reflecting the AE activity within specimens).Additionally,computed tomography analysis revealed intensified fracture networks and increasing three-dimensional fractal dimensions of coal specimens with higher IDVs.Finally,the coupling effect of TCLU and initial damage on the weakening mechanism of coal was investigated.Initial damage significantly reduced the structural integrity of coal by increasing the number of weak planes within coal specimens,contributing to the earlier activation and rapid expansion of fractures at low stress levels under TCLU and eventually accelerating the weakening process of coal.This study provides a scientific basis and theoretical support for the prevention and control of dynamic disasters in deep coal mining.展开更多
In recent years,acoustic logic gates has attracted growing interest in acoustics due to their promising applications in acoustic communication and signal processing.For practical implementation,these logic gates must ...In recent years,acoustic logic gates has attracted growing interest in acoustics due to their promising applications in acoustic communication and signal processing.For practical implementation,these logic gates must operate over a certain bandwidth to ensure reliable performance.However,current experimental realizations have predominantly been confined to single-frequency or narrowband operation,leaving their broadband capabilities largely unverified.To address this gap,we present both numerical and experimental demonstrations of three basic acoustic logic gates(OR,NOT,and AND)using a phased unit cell composed of a central channel flanked by two arrays of semicircular cavities.By leveraging phase modulation of the unit cells and linear interference of sound,we achieve these logic operations with a uniform threshold of I_(t)=0.25.Remarkably,the measured fractional bandwidths(bandwidth relative to center frequency)reach approximately 111.5%(OR),37.2%(NOT),and 48.5%(AND),demonstrating ultra-broadband functionality.The proposed logic gates combine exceptional bandwidth with structural simplicity,offering significant potential for applications in acoustic computing,information processing,and integrated acoustic systems.展开更多
While reinforcement learning-based underwater acoustic adaptive modulation shows promise for enabling environment-adaptive communication as supported by extensive simulation-based research,its practical performance re...While reinforcement learning-based underwater acoustic adaptive modulation shows promise for enabling environment-adaptive communication as supported by extensive simulation-based research,its practical performance remains underexplored in field investigations.To evaluate the practical applicability of this emerging technique in adverse shallow sea channels,a field experiment was conducted using three communication modes:orthogonal frequency division multiplexing(OFDM),M-ary frequency-shift keying(MFSK),and direct sequence spread spectrum(DSSS)for reinforcement learning-driven adaptive modulation.Specifically,a Q-learning method is used to select the optimal modulation mode according to the channel quality quantified by signal-to-noise ratio,multipath spread length,and Doppler frequency offset.Experimental results demonstrate that the reinforcement learning-based adaptive modulation scheme outperformed fixed threshold detection in terms of total throughput and average bit error rate,surpassing conventional adaptive modulation strategies.展开更多
We predict high-velocity magnetic domain wall(DW)motion driven by out-of-plane acoustic spin in surface acoustic waves(SAWs).We demonstrate that the SAW propagating at a 30-degree angle relative to the x-axis of a 128...We predict high-velocity magnetic domain wall(DW)motion driven by out-of-plane acoustic spin in surface acoustic waves(SAWs).We demonstrate that the SAW propagating at a 30-degree angle relative to the x-axis of a 128∘Y-LiNbO_(3) substrate exhibits uniform out-of-plane spin angular momentum.This acoustic spin triggers the DW motion at a velocity exceeding 50 m/s in a way that is similar to the spin-transfer-torque effect.This phenomenon highlights the potential of acoustic spin in enabling rapid DW displacement,offering an innovative approach to developing energy-efficient spintronic devices.展开更多
1.Challenges Thermoacoustic instability in combustors arises from the interaction between sound waves and unsteady heat release,commonly found in systems like gas turbines and aeroengines.This instability leads to und...1.Challenges Thermoacoustic instability in combustors arises from the interaction between sound waves and unsteady heat release,commonly found in systems like gas turbines and aeroengines.This instability leads to undesirable consequences such as structural damage and performance deterioration.The challenge lies in predicting and mitigating these instabilities due to the complex interplay of various physical phenomena like acoustic propagation,turbulent flow,and combustion chemistry,which are summarized in detail in Aimee S.Morgans and Dong Yang's published article.展开更多
Decorative construction typically accounts for 20–50%of total project costs.China introduces energy-saving panels,primarily composed of sand particles,to reduce its energy consumption.Most importantly,it has the abil...Decorative construction typically accounts for 20–50%of total project costs.China introduces energy-saving panels,primarily composed of sand particles,to reduce its energy consumption.Most importantly,it has the ability to efficiently resolve intricate acoustic issues with remarkable speed and convenience.This study focuses on sand-based energy-saving panels,which efficiently address complex acoustic issues while reducing energy consumption.Using Delany-Bazley empirical models and acoustic simulation software(Zorba,INSUL),four surface treatments(Plain-P,SA1,PF,SA2)were compared to optimize room acoustics.Results show that plain sand spray(Plain-P)exhibits the highest sound absorption capacity,with a noise reduction coefficient(NRC)of 0.85 and a sound absorption coefficient exceeding 0.9 in high frequencies.Simulation of rooms with sand-based wall coatings confirms its environmental friendliness and adaptability to curved surfaces,arched ceilings,and special-shaped walls.The results demonstrate that empirical models and simulation together improve the approach to studying acoustic parameters like sound absorption through sound impedance and propagation coefficient.Additionally,the material expresses excellent sound insulation,with an average transmission loss(TL)of approximately 70.71 dB.This research highlights the overlooked potential of sand-based materials,providing a practical solution for energy-efficient and acoustically optimized interior design,specifically emphasising a method that has not been paid much attention to.展开更多
Techniques for manipulating nanodroplets lie at the core of numerous miniaturized systems in chemical and biological research endeavors.In this study,we introduce a versatile methodology for calculating the acoustic v...Techniques for manipulating nanodroplets lie at the core of numerous miniaturized systems in chemical and biological research endeavors.In this study,we introduce a versatile methodology for calculating the acoustic vortex field,integrating hybrid wave equation principles with ray acoustics.This approach demonstrates remarkable consistency between simulated results and experimental observations.Importantly,both theoretical analysis and experimental validation confirm that particles whose diameters match the wavelength(Mie particles)can be effectively trapped within a focused acoustic vortex field,rotating in circular trajectories centered at the vortex center.This research significantly expands the scope of acoustic vortex manipulation for larger particles and introduces a novel implementation strategy with potential applications in targeted drug delivery for clinical adjuvant therapy.展开更多
Ultrasound neuromodulation is a powerful tool for brain investigation and holds great promise for treating brain diseases.However,due to the heterogeneous acoustic properties of skulls,existing ultrasound neuromodulat...Ultrasound neuromodulation is a powerful tool for brain investigation and holds great promise for treating brain diseases.However,due to the heterogeneous acoustic properties of skulls,existing ultrasound neuromodulation faces the challenge of severe transcranial acoustic attenuation.To overcome such limitations,we report an implantable bio-chip for visible and controllable mi-crowave-induced transcranial acoustic generation(MI-tAG).The bio-chip is soft,flexible,and biocompatible,with a thickness of 3mm,making it suitable for human intracranial implantation.The constituted fluid channels can cover an area of 50 mm×60 mm,enabling widefield neuronstimulation.The particles filled in the fluid channels have both high microwave absorption.ensuring efficient ultrasound generation,and magnetism,allowing noncontact and flexible ma-nipulation by external magnetic fields.The experimental results demonstrate that the optimal MI-tAG can be realized by the combination of particles arranged in a linear pattern and corre-sponding illumination via a linearly polarized microwave.Stability evaluation indicates that the particles can maintain a consistent acoustic intensity without degradation for at least seven days.The results of in vitro and in vivo experiments show that the MII-tAG can manipulate ultrasound sources and visibly locate them in real time.This study provides a potential innovative approach for future ultrasound neuromodulation,inspiring the development of more useful methods to advance brain research.This study introduces a promising innovative approach for transcranial acoustic generation,potentially inspiring the development of more effective methods for ad-vancing ultrasound neuromodulation.展开更多
This study explores a sensitivity analysis method based on the boundary element method(BEM)to address the computational complexity in acoustic analysis with ground reflection problems.The advantages of BEM in acoustic...This study explores a sensitivity analysis method based on the boundary element method(BEM)to address the computational complexity in acoustic analysis with ground reflection problems.The advantages of BEM in acoustic simulations and its high computational cost in broadband problems are examined.To improve efficiency,a Taylor series expansion is applied to decouple frequency-dependent terms in BEM.Additionally,the SecondOrder Arnoldi(SOAR)model order reduction method is integrated to reduce computational costs and enhance numerical stability.Furthermore,an isogeometric sensitivity boundary integral equation is formulated using the direct differentiation method,incorporating Cauchy principal value integrals and Hadamard finite part integrals to handle singularities.The proposed method improves the computational efficiency,and the acoustic sensitivity analysis provides theoretical support for further acoustic structure optimization.展开更多
[Objective] The aim was to study the effects of different acoustic frequency of insect sound （IS） and insect-music mixed sound （MS） treatment on the growth of 6 kinds of vegetables.[Method] The insect acoustic gro...[Objective] The aim was to study the effects of different acoustic frequency of insect sound （IS） and insect-music mixed sound （MS） treatment on the growth of 6 kinds of vegetables.[Method] The insect acoustic group,insect-music mixed group and normal control group were designed to determine the related indices of 6 kinds of vegetables in unified management regularly.[Result] After different acoustic frequency treatment,besides soybean plant height,dry root weight of cabbage and greengrocery,there was significant difference of plant height,fresh weight and dry weight between the other vegetables and control.Under acoustic frequency treatment,the growth situations of six kinds of vegetables were better than control.In the growth period,acoustic frequency treatment could promote height growth （except soybean） and edible part yield.[Conclusion] Both of IS and MS could promote the plant growth,but their effects had difference.展开更多
A type of combined optical fiber interferometric acoustic emission sensor is proposed. The sensor can be independent on the laser source and make light interference by matching the lengths of two arms,so it can be use...A type of combined optical fiber interferometric acoustic emission sensor is proposed. The sensor can be independent on the laser source and make light interference by matching the lengths of two arms,so it can be used to monitor the health of large structure. Theoretical analyses indicate that the system can be equivalent to the Michelson interferometer with two optical fiber loop reflectors,and its sensitivity has been remarkably increased because of the decrease of the losses of light energy. PZT is powered by DC regulator to control the operating point of the system,so the system can accurately detect feeble vibration which is generated by ultrasonic waves propagating on the surface of solid. The amplitude and the frequency of feeble vibration signal are obtained by detecting the output light intensity of interferometer and using Fourier transform technique. The results indicate that the system can be used to detect the acoustic emission signals by the frequency characteristics.展开更多
基金supported by the Major Research Development Program of Hubei Province,China(Grant Nos.2022BAA093 and 2022BAD163)the Open Research Fund of the State Key Laboratory of Geomechanics and Geotechnical Engineering,Institute of Rock and Soil Mechanics,Chinese Academy of Sciences(Grant No.SKLGME023008).
文摘With the growing global demand for energy,deep underground salt caverns are emerging as a potential solution for large-scale energy storage.In this study,multistage cyclic loading tests were conducted on rock salt at different temperatures in combination with real-time acoustic emission(AE)monitoring.The results show that the cumulative AE count increases stepwise with increasing cyclic stress.The peak frequency is concentrated primarily in the medium-frequency range,exhibiting a band distribution across low-,medium-,and high-frequency ranges.As the temperature increases,the proportion of low-frequency signals decreases from 14.32%to 5.76%,whereas the proportion of medium-frequency signals increases from 85.48%to 94.1%.The proportion of high-frequency signals remains relatively constant between 0.1%and 0.2%.The amplitude-count relationship of the AE signals demonstrates a strong negative power-law correlation.Furthermore,with increasing temperature,the negative power-law exponent of the amplitude gradually decreases,with the b value decreasing from 1.096 to 0.837 and the a value decreasing from 7.4871 to 6.6982.Under all four temperature conditions,the dominant failure mode in rock salt is tensile cracking.However,as the temperature increases,the proportion of tensile cracks decreases from 88.59%to 75.12%,whereas the proportion of shear cracks at 80℃is nearly double that at 20℃.This finding indicates that as the temperature increases,the ductility of the material increases,and the crack propagation mode shifts from tensile to shear.This research provides valuable insights for the design and stability assessment of salt cavern reservoirs for deep underground energy storage systems.
基金Project(U22A20603)supported by the National Natural Science Foundation of ChinaProject(2023YFC3008300)supported by the National Key Research and Development Program of China。
文摘To investigate the long-term stability of soft-hard interbedded rock masses with initial damage induced by earthquakes and periodic drying and wetting,this study prepared samples with different initial damage through cyclic loading and unloading(CLU)experiments followed by cyclic drying and wetting(CDW)experiments,and finally conducted creep experiments.The study analyzed the effects of initial damage on creep mechanical behavior,crack evolution,and explored failure precursor information,revealing the damage failure mechanisms.The results show that the structural characteristics of the rock mass control its macroscopic failure mode.Initial damage promotes microcrack development,influences the fracture mode,and increases the proportion of high-frequency(200−280 kHz)acoustic emission events during creep.Meanwhile,initial damage exacerbates creep characteristics,increasing the creep rate,shortening total creep failure time,and reducing long-term strength.The damage failure is attributed to:the generation of internal cracks and pores in the rock caused by CLU;mineral hydrolysis and expansion-contraction due to CDW,resulting in weakened intergranular cementation;and full development of cracks and pores under creep stress.Additionally,the deformation difference coefficient and the coefficient of variation of RA/AF values can serve as precursor indicators for creep failure.
基金supported by the National Natural Science Foundation of China under Grant No.12204062the Natural Science Foundation of Shandong Province under Grant No.ZR2022MF330。
文摘To enhance speech emotion recognition capability,this study constructs a speech emotion recognition model integrating the adaptive acoustic mixup(AAM)and improved coordinate and shuffle attention(ICASA)methods.The AAM method optimizes data augmentation by combining a sample selection strategy and dynamic interpolation coefficients,thus enabling information fusion of speech data with different emotions at the acoustic level.The ICASA method enhances feature extraction capability through dynamic fusion of the improved coordinate attention(ICA)and shuffle attention(SA)techniques.The ICA technique reduces computational overhead by employing depth-separable convolution and an h-swish activation function and captures long-range dependencies of multi-scale time-frequency features using the attention weights.The SA technique promotes feature interaction through channel shuffling,which helps the model learn richer and more discriminative emotional features.Experimental results demonstrate that,compared to the baseline model,the proposed model improves the weighted accuracy by 5.42%and 4.54%,and the unweighted accuracy by 3.37%and 3.85%on the IEMOCAP and RAVDESS datasets,respectively.These improvements were confirmed to be statistically significant by independent samples t-tests,further supporting the practical reliability and applicability of the proposed model in real-world emotion-aware speech systems.
基金Supported by National Natural Science Foundation of China(Grant No.51675021).
文摘The tire acoustic cavity resonance(TACR)noise is a significant source of the structure-borne noise inside a vehicle in the low-frequency range.This paper studies the noise dissipation effect of porous materials in reducing the TACR noise,an attempt to clarify the acoustic reduction mechanism and improve the accompanying vehicle interior noise level.A numerical model of a simplified tire cavity with rigid boundaries and acoustic excitation is established and further validated by the experiment.The effects of porous parameters on TACR frequency and sound pressure are then investigated and compared.The result reveals that the most influential material parameters are the porosity and material volume.It is also shown that the effectiveness of porous material in the mitigation of noise originates from the curliness of the material,which results in much larger acoustic impedance near the excitation position.Therefore,the sound absorption performance of the cavity attached with porous material proves to be excellent compared to that of the porous material itself.For further studying the damping effects of structural coupling,the flexible boundary of the tire tread is introduced.The results show that the porosity,material volume and structural loss factor of the tread all play important roles in reducing TACR noise.
基金supported in part by the National Key Research and Development Program of China (Grant No.2020YFC2201504)the National Natural Science Foundation of China (Grant Nos.12588101 and 12535002)。
文摘We investigate the null tests of cosmic accelerated expansion by using the baryon acoustic oscillation(BAO)data measured by the dark energy spectroscopic instrument(DESI)and reconstruct the dimensionless Hubble parameter E(z)from the DESI BAO Alcock-Paczynski(AP)data using Gaussian process to perform the null test.We find strong evidence of accelerated expansion from the DESI BAO AP data.By reconstructing the deceleration parameter q(z) from the DESI BAO AP data,we find that accelerated expansion persisted until z■0.7 with a 99.7%confidence level.Additionally,to provide insights into the Hubble tension problem,we propose combining the reconstructed E(z) with D_(H)/r_(d) data to derive a model-independent result r_(d)h=99.8±3.1 Mpc.This result is consistent with measurements from cosmic microwave background(CMB)anisotropies using the ΛCDM model.We also propose a model-independent method for reconstructing the comoving angular diameter distance D_(M)(z) from the distance modulus μ,using SNe Ia data and combining this result with DESI BAO data of D_(M)/r_(d) to constrain the value of r_(d).We find that the value of r_(d),derived from this model-independent method,is smaller than that obtained from CMB measurements,with a significant discrepancy of at least 4.17σ.All the conclusions drawn in this paper are independent of cosmological models and gravitational theories.
基金support from the National Natural Science Foundation of China(Grant Nos.52104207 and 52374214)the Shandong Provincial Youth Innovation Team Development Program for Higher Education Institutions(Grant No.2023KJ305).
文摘In the field of rock engineering,the influence of water is a dynamic process that exhibits varying effects over time and across different locations.To further understand how water influences the mechanical properties and acoustic emission(AE)behavior of rocks,this study conducted uniaxial compression experiments on sandstones with varying degrees of wetting under both natural conditions and water-chemical environments.In addition,the study combined AE equipment with digital image correlation(DIC)to monitor the entire failure process.Using the sliding window algorithm,the variation in the variance of AE characteristic parameters during the process of sandstone loading to failure is analyzed from the perspective of critical slowing down.This analysis enables the effective identification of the early warning signal before failure.The experimental findings suggest that an increase in wetting height results in a gradual decrease in peak stress,accompanied by a concomitant increase in the percentage of shear cracks.The characteristic parameters,including energy,amplitude,and ringing count,all exhibit critical slowing phenomena.The waveform of AE characteristic parameters of the same sample is similar,and the mutation time of the precursor signal is roughly the same.All signals appear in the irreversible plastic deformation stage of microcrack initiation.The integration of critical slowing down theory and the b-value early warning method facilitates a more comprehensive evaluation of the stability of rock mass,thereby significantly enhancing the efficiency and safety of disaster prevention measures.
基金supported by the National Key R&D Program of China(Grant No.2022YFC3004704)the National Natural Science Foundation of China(Grant No.52174166)Graduate Research and Innovation Foundation of Chongqing,China(Grant No.CYB23031),which were gratefully acknowledged.
文摘During deep coal mining,an instability failure of coal usually occurs under the combined effect of initial damage and triaxial cyclic loading and unloading(TCLU).Therefore,this study investigated the impact of initial damage on mechanical behavior and acoustic emission(AE)characteristics of coal under TCLU.Initial damage variables(IDVs)of coal specimens were quantified using preloading,followed by TCLU experiments to assess the deformation,energy distribution,and fracture development.The results revealed that the increase in IDVs significantly reduced the structural integrity of coal specimens,increased the cumulative irreversible strain,and enhanced the dissipated energy owing to microfracture expansion.Moreover,AE monitoring showed earlier activation of fractures and a higher occurrence of large-scale rupture events of coal specimens with high IDVs,which correlated with decreasing AE b values(reflecting the different scales of fracture within specimens)and increasing S values(reflecting the AE activity within specimens).Additionally,computed tomography analysis revealed intensified fracture networks and increasing three-dimensional fractal dimensions of coal specimens with higher IDVs.Finally,the coupling effect of TCLU and initial damage on the weakening mechanism of coal was investigated.Initial damage significantly reduced the structural integrity of coal by increasing the number of weak planes within coal specimens,contributing to the earlier activation and rapid expansion of fractures at low stress levels under TCLU and eventually accelerating the weakening process of coal.This study provides a scientific basis and theoretical support for the prevention and control of dynamic disasters in deep coal mining.
基金Project supported by the National Natural Science Foundation of China(Grant No.12174159)。
文摘In recent years,acoustic logic gates has attracted growing interest in acoustics due to their promising applications in acoustic communication and signal processing.For practical implementation,these logic gates must operate over a certain bandwidth to ensure reliable performance.However,current experimental realizations have predominantly been confined to single-frequency or narrowband operation,leaving their broadband capabilities largely unverified.To address this gap,we present both numerical and experimental demonstrations of three basic acoustic logic gates(OR,NOT,and AND)using a phased unit cell composed of a central channel flanked by two arrays of semicircular cavities.By leveraging phase modulation of the unit cells and linear interference of sound,we achieve these logic operations with a uniform threshold of I_(t)=0.25.Remarkably,the measured fractional bandwidths(bandwidth relative to center frequency)reach approximately 111.5%(OR),37.2%(NOT),and 48.5%(AND),demonstrating ultra-broadband functionality.The proposed logic gates combine exceptional bandwidth with structural simplicity,offering significant potential for applications in acoustic computing,information processing,and integrated acoustic systems.
基金funding from the National Key Research and Development Program of China(No.2018YFE0110000)the National Natural Science Foundation of China(No.11274259,No.11574258)the Science and Technology Commission Foundation of Shanghai(21DZ1205500)in support of the present research.
文摘While reinforcement learning-based underwater acoustic adaptive modulation shows promise for enabling environment-adaptive communication as supported by extensive simulation-based research,its practical performance remains underexplored in field investigations.To evaluate the practical applicability of this emerging technique in adverse shallow sea channels,a field experiment was conducted using three communication modes:orthogonal frequency division multiplexing(OFDM),M-ary frequency-shift keying(MFSK),and direct sequence spread spectrum(DSSS)for reinforcement learning-driven adaptive modulation.Specifically,a Q-learning method is used to select the optimal modulation mode according to the channel quality quantified by signal-to-noise ratio,multipath spread length,and Doppler frequency offset.Experimental results demonstrate that the reinforcement learning-based adaptive modulation scheme outperformed fixed threshold detection in terms of total throughput and average bit error rate,surpassing conventional adaptive modulation strategies.
基金supported by the National Key Research and Development Program of China(Grant No.2022YFE0103300)the open research fund of Songshan Lake Materials Laboratory(Grant No.2023SLABFN26)the Natural Science Foundation of Hubei Province(Grant No.2022CFA088)。
文摘We predict high-velocity magnetic domain wall(DW)motion driven by out-of-plane acoustic spin in surface acoustic waves(SAWs).We demonstrate that the SAW propagating at a 30-degree angle relative to the x-axis of a 128∘Y-LiNbO_(3) substrate exhibits uniform out-of-plane spin angular momentum.This acoustic spin triggers the DW motion at a velocity exceeding 50 m/s in a way that is similar to the spin-transfer-torque effect.This phenomenon highlights the potential of acoustic spin in enabling rapid DW displacement,offering an innovative approach to developing energy-efficient spintronic devices.
文摘1.Challenges Thermoacoustic instability in combustors arises from the interaction between sound waves and unsteady heat release,commonly found in systems like gas turbines and aeroengines.This instability leads to undesirable consequences such as structural damage and performance deterioration.The challenge lies in predicting and mitigating these instabilities due to the complex interplay of various physical phenomena like acoustic propagation,turbulent flow,and combustion chemistry,which are summarized in detail in Aimee S.Morgans and Dong Yang's published article.
基金supported by China Scholarship Counsil(CSC)(grant number:202206935003)Shanxi Province Nature and Science(grant number:202203021222098).
文摘Decorative construction typically accounts for 20–50%of total project costs.China introduces energy-saving panels,primarily composed of sand particles,to reduce its energy consumption.Most importantly,it has the ability to efficiently resolve intricate acoustic issues with remarkable speed and convenience.This study focuses on sand-based energy-saving panels,which efficiently address complex acoustic issues while reducing energy consumption.Using Delany-Bazley empirical models and acoustic simulation software(Zorba,INSUL),four surface treatments(Plain-P,SA1,PF,SA2)were compared to optimize room acoustics.Results show that plain sand spray(Plain-P)exhibits the highest sound absorption capacity,with a noise reduction coefficient(NRC)of 0.85 and a sound absorption coefficient exceeding 0.9 in high frequencies.Simulation of rooms with sand-based wall coatings confirms its environmental friendliness and adaptability to curved surfaces,arched ceilings,and special-shaped walls.The results demonstrate that empirical models and simulation together improve the approach to studying acoustic parameters like sound absorption through sound impedance and propagation coefficient.Additionally,the material expresses excellent sound insulation,with an average transmission loss(TL)of approximately 70.71 dB.This research highlights the overlooked potential of sand-based materials,providing a practical solution for energy-efficient and acoustically optimized interior design,specifically emphasising a method that has not been paid much attention to.
基金Project supported by the National Key R&D Program of China(Grant No.2023YFE0201900)。
文摘Techniques for manipulating nanodroplets lie at the core of numerous miniaturized systems in chemical and biological research endeavors.In this study,we introduce a versatile methodology for calculating the acoustic vortex field,integrating hybrid wave equation principles with ray acoustics.This approach demonstrates remarkable consistency between simulated results and experimental observations.Importantly,both theoretical analysis and experimental validation confirm that particles whose diameters match the wavelength(Mie particles)can be effectively trapped within a focused acoustic vortex field,rotating in circular trajectories centered at the vortex center.This research significantly expands the scope of acoustic vortex manipulation for larger particles and introduces a novel implementation strategy with potential applications in targeted drug delivery for clinical adjuvant therapy.
基金supported by the National Key R&D Program of China under grant 2023YFF0715303in part by the National Natural Science Foundation of China under Grant Nos.62305148,62105140,62022037,and 61775028+2 种基金in part by the Department of Science and Technology of Guangdong Province under Grant Nos.2019ZT08Y191 and 2022B1212010003in part by the Shenzhen Science and Technology Program under Grant Nos.JCYJ20220530114010023,RCJC20231211090039066,20231116104616001,KQTD20190929172743294,JCYJ20230807093105010,RCBS20231211090802011in part by the Startup Grant from Southern University of Science and Technology under Grant No.PDJH2021C008.
文摘Ultrasound neuromodulation is a powerful tool for brain investigation and holds great promise for treating brain diseases.However,due to the heterogeneous acoustic properties of skulls,existing ultrasound neuromodulation faces the challenge of severe transcranial acoustic attenuation.To overcome such limitations,we report an implantable bio-chip for visible and controllable mi-crowave-induced transcranial acoustic generation(MI-tAG).The bio-chip is soft,flexible,and biocompatible,with a thickness of 3mm,making it suitable for human intracranial implantation.The constituted fluid channels can cover an area of 50 mm×60 mm,enabling widefield neuronstimulation.The particles filled in the fluid channels have both high microwave absorption.ensuring efficient ultrasound generation,and magnetism,allowing noncontact and flexible ma-nipulation by external magnetic fields.The experimental results demonstrate that the optimal MI-tAG can be realized by the combination of particles arranged in a linear pattern and corre-sponding illumination via a linearly polarized microwave.Stability evaluation indicates that the particles can maintain a consistent acoustic intensity without degradation for at least seven days.The results of in vitro and in vivo experiments show that the MII-tAG can manipulate ultrasound sources and visibly locate them in real time.This study provides a potential innovative approach for future ultrasound neuromodulation,inspiring the development of more useful methods to advance brain research.This study introduces a promising innovative approach for transcranial acoustic generation,potentially inspiring the development of more effective methods for ad-vancing ultrasound neuromodulation.
基金supported by the Shanxi Scholarship Council of China(Grant No.2023-036)the Natural Science Foundation of Shanxi Province(Grant No.202303021222020).
文摘This study explores a sensitivity analysis method based on the boundary element method(BEM)to address the computational complexity in acoustic analysis with ground reflection problems.The advantages of BEM in acoustic simulations and its high computational cost in broadband problems are examined.To improve efficiency,a Taylor series expansion is applied to decouple frequency-dependent terms in BEM.Additionally,the SecondOrder Arnoldi(SOAR)model order reduction method is integrated to reduce computational costs and enhance numerical stability.Furthermore,an isogeometric sensitivity boundary integral equation is formulated using the direct differentiation method,incorporating Cauchy principal value integrals and Hadamard finite part integrals to handle singularities.The proposed method improves the computational efficiency,and the acoustic sensitivity analysis provides theoretical support for further acoustic structure optimization.
基金Supported by Important Project of Science and Technology of Zhejiang Province(2008C12056)~~
文摘[Objective] The aim was to study the effects of different acoustic frequency of insect sound （IS） and insect-music mixed sound （MS） treatment on the growth of 6 kinds of vegetables.[Method] The insect acoustic group,insect-music mixed group and normal control group were designed to determine the related indices of 6 kinds of vegetables in unified management regularly.[Result] After different acoustic frequency treatment,besides soybean plant height,dry root weight of cabbage and greengrocery,there was significant difference of plant height,fresh weight and dry weight between the other vegetables and control.Under acoustic frequency treatment,the growth situations of six kinds of vegetables were better than control.In the growth period,acoustic frequency treatment could promote height growth （except soybean） and edible part yield.[Conclusion] Both of IS and MS could promote the plant growth,but their effects had difference.
基金the Fundamental Research Foundation of Harbin Engineering University, (grant number HEUF 04017)
文摘A type of combined optical fiber interferometric acoustic emission sensor is proposed. The sensor can be independent on the laser source and make light interference by matching the lengths of two arms,so it can be used to monitor the health of large structure. Theoretical analyses indicate that the system can be equivalent to the Michelson interferometer with two optical fiber loop reflectors,and its sensitivity has been remarkably increased because of the decrease of the losses of light energy. PZT is powered by DC regulator to control the operating point of the system,so the system can accurately detect feeble vibration which is generated by ultrasonic waves propagating on the surface of solid. The amplitude and the frequency of feeble vibration signal are obtained by detecting the output light intensity of interferometer and using Fourier transform technique. The results indicate that the system can be used to detect the acoustic emission signals by the frequency characteristics.
