To tackle the issue of notch frequency and center frequency drift of the L(0,1)mode guided wave in ultra⁃sonic guided wave⁃based stress monitoring of prestressed steel strands,a method using higher⁃order mode plateau ...To tackle the issue of notch frequency and center frequency drift of the L(0,1)mode guided wave in ultra⁃sonic guided wave⁃based stress monitoring of prestressed steel strands,a method using higher⁃order mode plateau fre⁃quencies is adopted.First,the correlation between group velocity peaks and phase velocities at these plateau frequen⁃cies is analyzed.This analysis establishes a quantitative rela⁃tionship between phase velocity and stress in the steel strand,providing a theoretical foundation for stress monitor⁃ing.Then the two⁃dimensional Fourier transform is em⁃ployed to separate wave modes.Dynamic programming techniques are applied in the frequency⁃velocity domain to extract higher⁃order modes.By identifying the group veloc⁃ity peaks of these separated higher⁃order modes,the plateau frequencies of guided waves are determined,enabling indi⁃rect measurement of stress in the steel strand.To validate this method,finite element simulations are conducted under three scenarios.Results show that the higher⁃order modes of transient signals from three different positions can be ac⁃curately extracted,leading to successful cable stress moni⁃toring.This approach effectively circumvents the issue of guided wave frequency drift and improves stress monitoring accuracy.Consequently,it significantly improves the appli⁃cation of ultrasonic guided wave technology in structural health monitoring.展开更多
BACKGROUND Adrenocortical oncocytoma is a rare,mostly benign,nonfunctional tumor that is typically detected incidentally.Its diagnosis is challenging because of the absence of distinctive imaging characteristics,neces...BACKGROUND Adrenocortical oncocytoma is a rare,mostly benign,nonfunctional tumor that is typically detected incidentally.Its diagnosis is challenging because of the absence of distinctive imaging characteristics,necessitating pathological validation.CASE SUMMARY We present a case report of a 35-year-old woman with an adrenal mass located on the left side,where endoscopic ultrasound-guided fine-needle aspiration(EUSFNA)was performed after comprehensive diagnostic assessment.Our results are consistent with those of previously documented cases regarding tumor demographics and anatomical location.Given the limited number of reports on this condition,long-term follow-up is crucial to enhance our understanding of its prognosis.CONCLUSION For patients with adrenocortical oncocytoma,EUS-FNA can enables collection of preoperative tissue specimens leading to suitable treatment strategies.展开更多
Multi-layer riveted structures are widely applied to aircraft.During the service,cracks may appear within these structures due to stress concentration of the riveted holes.The guided wave monitoring has been proved to...Multi-layer riveted structures are widely applied to aircraft.During the service,cracks may appear within these structures due to stress concentration of the riveted holes.The guided wave monitoring has been proved to be an effective tool to deal with this problem.However,there is a lack of understanding of the wave propagation process across such kinds of structures.This study proposes a piezoelectric guided wave simulation method to reveal the propagation of guided waves in multi-layer riveted structures.Effects of pretension force,friction coefficient,and cracks that might influence wave characteristics are studied.The guided wave simulation data is compared with the experimental results and the results verify the simulation model.Then the guided wave propagation in a more complex long-beam butt joint structure is further simulated.展开更多
Using periodic refractive index perturbations,the Brillouin zone is folded,transforming the guided modes in a metasurface into guided resonances with arbitrarily high quality-factors.The incorporation of phase change ...Using periodic refractive index perturbations,the Brillouin zone is folded,transforming the guided modes in a metasurface into guided resonances with arbitrarily high quality-factors.The incorporation of phase change materials within the metasurface enables dynamic modulation of the guided modes.The system’s symmetry ensures a polarization-independent response under normal incidence.Furthermore,the metasurface exhibits excellent sensing performance,demonstrating its potential for advanced photonic applications.展开更多
Dear Editor,Barry et al.'s study[1],“Physician Attitudes About Ultrasound‐Guided Procedures,”investigates clinicians'views on ultra-sound‐guided interventions and their openness to technological advancemen...Dear Editor,Barry et al.'s study[1],“Physician Attitudes About Ultrasound‐Guided Procedures,”investigates clinicians'views on ultra-sound‐guided interventions and their openness to technological advancements.The group surveyed 116 physicians and found that a majority(57.5%)disagreed that there was a steep learning curve for ultrasound‐guided procedures,and 85%felt confident in identifying anatomical structures under ultrasound.Attitudes toward supplemental software were mixed,though 55.4%sup-ported real‐time 3D reconstruction.Notably,physicians without formal training were significantly more receptive to additional software(p=0.0389).Radiologists perceived greater procedural complexity and were less enthusiastic about technological aids.These findings highlight a paradox:Ultrasound is perceived as accessible,but untrained clinicians may rely on technology to compensate for skill gaps.The study underscores the impor-tance of addressing training disparities and leveraging innova-tion to enhance procedural safety and efficiency.展开更多
Correction to:Neuroscience Bulletin https://doi.org/10.1007/s12264-025-01371-x In this article the affiliation"Department of Circuit Theory,Faculty of Electrical Engineering,Czech Technical University in Prague,M...Correction to:Neuroscience Bulletin https://doi.org/10.1007/s12264-025-01371-x In this article the affiliation"Department of Circuit Theory,Faculty of Electrical Engineering,Czech Technical University in Prague,Member of the Epilepsy Research Centre Prague-EpiReC Consortium,Prague,Czechia"should only be assigned to Radek Janca and Petr Jezdik.It is removed from the authors:Jiri Hammer,Michaela Kajsova,Adam Kalina,Petr Marusic,and Kamil Vlcek.展开更多
Enhancing website security is crucial to combat malicious activities,and CAPTCHA(Completely Automated Public Turing tests to tell Computers and Humans Apart)has become a key method to distinguish humans from bots.Whil...Enhancing website security is crucial to combat malicious activities,and CAPTCHA(Completely Automated Public Turing tests to tell Computers and Humans Apart)has become a key method to distinguish humans from bots.While text-based CAPTCHAs are designed to challenge machines while remaining human-readable,recent advances in deep learning have enabled models to recognize them with remarkable efficiency.In this regard,we propose a novel two-layer visual attention framework for CAPTCHA recognition that builds on traditional attention mechanisms by incorporating Guided Visual Attention(GVA),which sharpens focus on relevant visual features.We have specifically adapted the well-established image captioning task to address this need.Our approach utilizes the first-level attention module as guidance to the second-level attention component,incorporating two LSTM(Long Short-Term Memory)layers to enhance CAPTCHA recognition.Our extensive evaluation across four diverse datasets—Weibo,BoC(Bank of China),Gregwar,and Captcha 0.3—shows the adaptability and efficacy of our method.Our approach demonstrated impressive performance,achieving an accuracy of 96.70%for BoC and 95.92%for Webo.These results underscore the effectiveness of our method in accurately recognizing and processing CAPTCHA datasets,showcasing its robustness,reliability,and ability to handle varied challenges in CAPTCHA recognition.展开更多
In complex environments such as high dynamics and weak signals,a satellite signal compensation method based on prefabricated trajectory assistance and an improved adaptive Kalman filter is proposed for a 155 mm differ...In complex environments such as high dynamics and weak signals,a satellite signal compensation method based on prefabricated trajectory assistance and an improved adaptive Kalman filter is proposed for a 155 mm differential rotating rear-body control-guided projectile to address the situation of satellite signal flickering and loss in projectile navigation systems due to environmental limitations.First,establish the system state and measurement equation when receiving satellite signals normally.Second,a seven-degree-of-freedom external ballistic model is constructed,and the ideal trajectory output from the ballistic model is used to provide the virtual motion state of the projectile,which is input into a filter as a substitute observation when satellite signals are lost.Finally,an adaptive Kalman filter(AKF)is designed,the proposed adaptive Kalman filter can accurately adjust the estimation error covariance matrix and Kalman gain in real-time based on information covariance mismatch.The simulation results show that compared to the classical Kalman filter,it can reduce the average positioning error by more than 38.21%in the case of short-term and full-range loss of satellite signals,providing a new idea for the integrated navigation of projectiles with incomplete information under the condition of satellite signal loss.展开更多
Fatigue damage is a primary contributor to the failure of composite structures,underscoring the critical importance of monitoring its progression to ensure structural safety.This paper introduces an innovative approac...Fatigue damage is a primary contributor to the failure of composite structures,underscoring the critical importance of monitoring its progression to ensure structural safety.This paper introduces an innovative approach to fatigue damage monitoring in composite structures,leveraging a hybrid methodology that integrates the Whale Optimization Algorithm(WOA)-Backpropagation(BP)neural network with an ultrasonic guided wave feature selection algorithm.Initially,a network of piezoelectric ceramic sensors is employed to transmit and capture ultrasonic-guided waves,thereby establishing a signal space that correlates with the structural condition.Subsequently,the Relief-F algorithm is applied for signal feature extraction,culminating in the formation of a feature matrix.This matrix is then utilized to train the WOA-BP neural network,which optimizes the fatigue damage identification model globally.The proposed model’s efficacy in quantifying fatigue damage is tested against fatigue test datasets,with its performance benchmarked against the traditional BP neural network algorithm.The findings demonstrate that the WOA-BP neural network model not only surpasses the BP model in predictive accuracy but also exhibits enhanced global search capabilities.The effect of different sensor-receiver path signals on the model damage recognition results is also discussed.The results of the discussion found that the path directly through the damaged area is more accurate in modeling damage recognition compared to the path signals away from the damaged area.Consequently,the proposed monitoring method in the fatigue test dataset is adept at accurately tracking and recognizing the progression of fatigue damage.展开更多
Genome rearrangement is an important process that leads to genetic diversity,including mutation-related insertions,deletions,or inversions in the genome[1,2].
Legendre polynomial method is well-known in modeling acoustic wave characteristics.This method uses for the mechanical displacements a single polynomial expansion over the entire sandwich layers.This results in a limi...Legendre polynomial method is well-known in modeling acoustic wave characteristics.This method uses for the mechanical displacements a single polynomial expansion over the entire sandwich layers.This results in a limitation in the accuracy of the field profile restitution.Thus,it can deal with the guided waves in layered sandwich only when the material properties of adjacent layers do not change significantly.Despite the great efforts regarding this issue in the literature,there remain open questions.One of them is:“what is the exact threshold of contrasting material properties of adjacent layers for which this polynomial method cannot correctly restitute the roots of guided waves?”We investigated this numerical issue using the calculated guided phase velocities in 0°/φ/0°-carbon fibre reinforced plastics(CFRP)sandwich plates with gradually increasing angleφ.Then,we approached this numerical problem by varying the middle layer thickness h90°for the 0°/90°/0°-CFRP sandwich structure,and we proposed an exact thickness threshold of the middle layer for the Legendre polynomial method limitations.We showed that the polynomial method fails to calculate the quasi-symmetric Lamb mode in 0°/φ/0°-CFRP whenφ>25°.Moreover,we introduced a new Lamb mode so-called minimum-group-velocity that has never been addressed in literature.展开更多
The visual noise of each light intensity area is different when the image is drawn by Monte Carlo method.However,the existing denoising algorithms have limited denoising performance under complex lighting conditions a...The visual noise of each light intensity area is different when the image is drawn by Monte Carlo method.However,the existing denoising algorithms have limited denoising performance under complex lighting conditions and are easy to lose detailed information.So we propose a rendered image denoising method with filtering guided by lighting information.First,we design an image segmentation algorithm based on lighting information to segment the image into different illumination areas.Then,we establish the parameter prediction model guided by lighting information for filtering(PGLF)to predict the filtering parameters of different illumination areas.For different illumination areas,we use these filtering parameters to construct area filters,and the filters are guided by the lighting information to perform sub-area filtering.Finally,the filtering results are fused with auxiliary features to output denoised images for improving the overall denoising effect of the image.Under the physically based rendering tool(PBRT)scene and Tungsten dataset,the experimental results show that compared with other guided filtering denoising methods,our method improves the peak signal-to-noise ratio(PSNR)metrics by 4.2164 dB on average and the structural similarity index(SSIM)metrics by 7.8%on average.This shows that our method can better reduce the noise in complex lighting scenesand improvethe imagequality.展开更多
To the Editor:Living donor liver transplantation continues to be a widely ac-cepted treatment for end-stage liver diseases[1].However,biliary complications remain a significant challenge,attributable to both surgical ...To the Editor:Living donor liver transplantation continues to be a widely ac-cepted treatment for end-stage liver diseases[1].However,biliary complications remain a significant challenge,attributable to both surgical and nonsurgical factors.These complications include bile leakage,biliary stricture,and choledocholithiasis,with a reported incidence of biliary stricture in pediatric living donor liver recip-ients ranging from 10%to 35%[2].Commonly employed thera-peutic approaches for biliary complications are endoscopic retro-grade cholangiopancreatography(ERCP),percutaneous transhepatic cholangioscopic lithotomy(PTCSL),and surgery,with ERCP often being the preferred initial treatment.展开更多
Coronaviruses are single-stranded,positive-sense RNA enveloped viruses that have posed a significant threat to human health over the past few decades,particularly severe acute respiratory syndrome coronavirus(SARS-CoV...Coronaviruses are single-stranded,positive-sense RNA enveloped viruses that have posed a significant threat to human health over the past few decades,particularly severe acute respiratory syndrome coronavirus(SARS-CoV),Middle East respiratory syndrome coronavirus(MERS-CoV),and SARS-CoV-2.These viruses have caused widespread infections and fatalities,with profound impacts on global economies,social life,and public health systems.Due to their broad host range in natural settings and the consequent high potential for zoonotic spillover events,a thorough investigation of the common viral mechanisms and the identification of druggable targets for pan-coronavirus antiviral development are of utmost importance.展开更多
In the process of launching guided projectile under the conventional system, it is difficult to effectively obtain the precise navigation parameters of the projectile in the high dynamic environment. Aiming at this pr...In the process of launching guided projectile under the conventional system, it is difficult to effectively obtain the precise navigation parameters of the projectile in the high dynamic environment. Aiming at this problem, this paper describes a new system of guided ammunition based on tail spin reduction. After analyzing the mechanism of the ammunition's tail spin reduction, a navigation method of large scale difference tail control simple guided ammunition based on speed constraint is proposed. In this method,the corresponding navigation constraints can be carried out by combining the rotation speed state of the ammunition itself, and the optimal solution of navigation parameters during the flight of the missile can be obtained by Extended Kalman Filter(EKF). Finally, the performance of the proposed method was verified by the simulation environment, and the hardware-in-the-loop simulation test and flight test were carried out to verify the performance of the method in the real environment. The experimental results show that the proposed method can achieve the optimal estimation of navigation parameters for simple guided ammunition with large-scale difference tail control. Under the conditions of simulation test and hardware-in-loop simulation test, the position and velocity errors calculated by the method in this paper converged. Under the condition of flight test, the spatial average error calculated by the method described in this paper is 6.17 m, and the spatial error of the final landing point is 3.50 m.Through this method, the accurate acquisition of navigation parameters in the process of projectile launching is effectively realized.展开更多
基金The National Natural Science Foundation of China(No.52278303).
文摘To tackle the issue of notch frequency and center frequency drift of the L(0,1)mode guided wave in ultra⁃sonic guided wave⁃based stress monitoring of prestressed steel strands,a method using higher⁃order mode plateau fre⁃quencies is adopted.First,the correlation between group velocity peaks and phase velocities at these plateau frequen⁃cies is analyzed.This analysis establishes a quantitative rela⁃tionship between phase velocity and stress in the steel strand,providing a theoretical foundation for stress monitor⁃ing.Then the two⁃dimensional Fourier transform is em⁃ployed to separate wave modes.Dynamic programming techniques are applied in the frequency⁃velocity domain to extract higher⁃order modes.By identifying the group veloc⁃ity peaks of these separated higher⁃order modes,the plateau frequencies of guided waves are determined,enabling indi⁃rect measurement of stress in the steel strand.To validate this method,finite element simulations are conducted under three scenarios.Results show that the higher⁃order modes of transient signals from three different positions can be ac⁃curately extracted,leading to successful cable stress moni⁃toring.This approach effectively circumvents the issue of guided wave frequency drift and improves stress monitoring accuracy.Consequently,it significantly improves the appli⁃cation of ultrasonic guided wave technology in structural health monitoring.
文摘BACKGROUND Adrenocortical oncocytoma is a rare,mostly benign,nonfunctional tumor that is typically detected incidentally.Its diagnosis is challenging because of the absence of distinctive imaging characteristics,necessitating pathological validation.CASE SUMMARY We present a case report of a 35-year-old woman with an adrenal mass located on the left side,where endoscopic ultrasound-guided fine-needle aspiration(EUSFNA)was performed after comprehensive diagnostic assessment.Our results are consistent with those of previously documented cases regarding tumor demographics and anatomical location.Given the limited number of reports on this condition,long-term follow-up is crucial to enhance our understanding of its prognosis.CONCLUSION For patients with adrenocortical oncocytoma,EUS-FNA can enables collection of preoperative tissue specimens leading to suitable treatment strategies.
文摘Multi-layer riveted structures are widely applied to aircraft.During the service,cracks may appear within these structures due to stress concentration of the riveted holes.The guided wave monitoring has been proved to be an effective tool to deal with this problem.However,there is a lack of understanding of the wave propagation process across such kinds of structures.This study proposes a piezoelectric guided wave simulation method to reveal the propagation of guided waves in multi-layer riveted structures.Effects of pretension force,friction coefficient,and cracks that might influence wave characteristics are studied.The guided wave simulation data is compared with the experimental results and the results verify the simulation model.Then the guided wave propagation in a more complex long-beam butt joint structure is further simulated.
基金supported by the National Natural Science Foundation of China(Grant No.12347101).
文摘Using periodic refractive index perturbations,the Brillouin zone is folded,transforming the guided modes in a metasurface into guided resonances with arbitrarily high quality-factors.The incorporation of phase change materials within the metasurface enables dynamic modulation of the guided modes.The system’s symmetry ensures a polarization-independent response under normal incidence.Furthermore,the metasurface exhibits excellent sensing performance,demonstrating its potential for advanced photonic applications.
文摘Dear Editor,Barry et al.'s study[1],“Physician Attitudes About Ultrasound‐Guided Procedures,”investigates clinicians'views on ultra-sound‐guided interventions and their openness to technological advancements.The group surveyed 116 physicians and found that a majority(57.5%)disagreed that there was a steep learning curve for ultrasound‐guided procedures,and 85%felt confident in identifying anatomical structures under ultrasound.Attitudes toward supplemental software were mixed,though 55.4%sup-ported real‐time 3D reconstruction.Notably,physicians without formal training were significantly more receptive to additional software(p=0.0389).Radiologists perceived greater procedural complexity and were less enthusiastic about technological aids.These findings highlight a paradox:Ultrasound is perceived as accessible,but untrained clinicians may rely on technology to compensate for skill gaps.The study underscores the impor-tance of addressing training disparities and leveraging innova-tion to enhance procedural safety and efficiency.
文摘Correction to:Neuroscience Bulletin https://doi.org/10.1007/s12264-025-01371-x In this article the affiliation"Department of Circuit Theory,Faculty of Electrical Engineering,Czech Technical University in Prague,Member of the Epilepsy Research Centre Prague-EpiReC Consortium,Prague,Czechia"should only be assigned to Radek Janca and Petr Jezdik.It is removed from the authors:Jiri Hammer,Michaela Kajsova,Adam Kalina,Petr Marusic,and Kamil Vlcek.
基金supported by the National Natural Science Foundation of China(Nos.U22A2034,62177047)High Caliber Foreign Experts Introduction Plan funded by MOST,and Central South University Research Programme of Advanced Interdisciplinary Studies(No.2023QYJC020).
文摘Enhancing website security is crucial to combat malicious activities,and CAPTCHA(Completely Automated Public Turing tests to tell Computers and Humans Apart)has become a key method to distinguish humans from bots.While text-based CAPTCHAs are designed to challenge machines while remaining human-readable,recent advances in deep learning have enabled models to recognize them with remarkable efficiency.In this regard,we propose a novel two-layer visual attention framework for CAPTCHA recognition that builds on traditional attention mechanisms by incorporating Guided Visual Attention(GVA),which sharpens focus on relevant visual features.We have specifically adapted the well-established image captioning task to address this need.Our approach utilizes the first-level attention module as guidance to the second-level attention component,incorporating two LSTM(Long Short-Term Memory)layers to enhance CAPTCHA recognition.Our extensive evaluation across four diverse datasets—Weibo,BoC(Bank of China),Gregwar,and Captcha 0.3—shows the adaptability and efficacy of our method.Our approach demonstrated impressive performance,achieving an accuracy of 96.70%for BoC and 95.92%for Webo.These results underscore the effectiveness of our method in accurately recognizing and processing CAPTCHA datasets,showcasing its robustness,reliability,and ability to handle varied challenges in CAPTCHA recognition.
基金funded by the National Natural Science Foundation of China (Grant No. 62471048)Open Fund Project of Beijing Key Laboratory of High Dynamic Navigation TechnologyKey Laboratory Fund Project of Modern Measurement and Control Technology, Ministry of Education
文摘In complex environments such as high dynamics and weak signals,a satellite signal compensation method based on prefabricated trajectory assistance and an improved adaptive Kalman filter is proposed for a 155 mm differential rotating rear-body control-guided projectile to address the situation of satellite signal flickering and loss in projectile navigation systems due to environmental limitations.First,establish the system state and measurement equation when receiving satellite signals normally.Second,a seven-degree-of-freedom external ballistic model is constructed,and the ideal trajectory output from the ballistic model is used to provide the virtual motion state of the projectile,which is input into a filter as a substitute observation when satellite signals are lost.Finally,an adaptive Kalman filter(AKF)is designed,the proposed adaptive Kalman filter can accurately adjust the estimation error covariance matrix and Kalman gain in real-time based on information covariance mismatch.The simulation results show that compared to the classical Kalman filter,it can reduce the average positioning error by more than 38.21%in the case of short-term and full-range loss of satellite signals,providing a new idea for the integrated navigation of projectiles with incomplete information under the condition of satellite signal loss.
基金funded by the Key Program of the National Natural Science Foundation of China(U2341235)Youth Fund for Basic Research Program of Jiangnan University(JUSRP123003)+2 种基金Postgraduate Research&Practice Innovation Program of Jiangsu Province(SJCX23_1237)the National Key R&D Program of China(2018YFA0702800)Key Technologies R&D Program of CNBM(2023SJYL01).
文摘Fatigue damage is a primary contributor to the failure of composite structures,underscoring the critical importance of monitoring its progression to ensure structural safety.This paper introduces an innovative approach to fatigue damage monitoring in composite structures,leveraging a hybrid methodology that integrates the Whale Optimization Algorithm(WOA)-Backpropagation(BP)neural network with an ultrasonic guided wave feature selection algorithm.Initially,a network of piezoelectric ceramic sensors is employed to transmit and capture ultrasonic-guided waves,thereby establishing a signal space that correlates with the structural condition.Subsequently,the Relief-F algorithm is applied for signal feature extraction,culminating in the formation of a feature matrix.This matrix is then utilized to train the WOA-BP neural network,which optimizes the fatigue damage identification model globally.The proposed model’s efficacy in quantifying fatigue damage is tested against fatigue test datasets,with its performance benchmarked against the traditional BP neural network algorithm.The findings demonstrate that the WOA-BP neural network model not only surpasses the BP model in predictive accuracy but also exhibits enhanced global search capabilities.The effect of different sensor-receiver path signals on the model damage recognition results is also discussed.The results of the discussion found that the path directly through the damaged area is more accurate in modeling damage recognition compared to the path signals away from the damaged area.Consequently,the proposed monitoring method in the fatigue test dataset is adept at accurately tracking and recognizing the progression of fatigue damage.
基金supported by grants(92168103,32171417,2019CXJQ01)from the National Nature Science Foundation of China,Shanghai Municipal GovernmentPeak Disciplines(Type IV)of Institutions of Higher Learning in Shanghai.
文摘Genome rearrangement is an important process that leads to genetic diversity,including mutation-related insertions,deletions,or inversions in the genome[1,2].
基金supported by the National Natural Science Foundation of China(Grant No.12102131).
文摘Legendre polynomial method is well-known in modeling acoustic wave characteristics.This method uses for the mechanical displacements a single polynomial expansion over the entire sandwich layers.This results in a limitation in the accuracy of the field profile restitution.Thus,it can deal with the guided waves in layered sandwich only when the material properties of adjacent layers do not change significantly.Despite the great efforts regarding this issue in the literature,there remain open questions.One of them is:“what is the exact threshold of contrasting material properties of adjacent layers for which this polynomial method cannot correctly restitute the roots of guided waves?”We investigated this numerical issue using the calculated guided phase velocities in 0°/φ/0°-carbon fibre reinforced plastics(CFRP)sandwich plates with gradually increasing angleφ.Then,we approached this numerical problem by varying the middle layer thickness h90°for the 0°/90°/0°-CFRP sandwich structure,and we proposed an exact thickness threshold of the middle layer for the Legendre polynomial method limitations.We showed that the polynomial method fails to calculate the quasi-symmetric Lamb mode in 0°/φ/0°-CFRP whenφ>25°.Moreover,we introduced a new Lamb mode so-called minimum-group-velocity that has never been addressed in literature.
基金supported by the National Natural Science(No.U19A2063)the Jilin Provincial Development Program of Science and Technology (No.20230201080GX)the Jilin Province Education Department Scientific Research Project (No.JJKH20230851KJ)。
文摘The visual noise of each light intensity area is different when the image is drawn by Monte Carlo method.However,the existing denoising algorithms have limited denoising performance under complex lighting conditions and are easy to lose detailed information.So we propose a rendered image denoising method with filtering guided by lighting information.First,we design an image segmentation algorithm based on lighting information to segment the image into different illumination areas.Then,we establish the parameter prediction model guided by lighting information for filtering(PGLF)to predict the filtering parameters of different illumination areas.For different illumination areas,we use these filtering parameters to construct area filters,and the filters are guided by the lighting information to perform sub-area filtering.Finally,the filtering results are fused with auxiliary features to output denoised images for improving the overall denoising effect of the image.Under the physically based rendering tool(PBRT)scene and Tungsten dataset,the experimental results show that compared with other guided filtering denoising methods,our method improves the peak signal-to-noise ratio(PSNR)metrics by 4.2164 dB on average and the structural similarity index(SSIM)metrics by 7.8%on average.This shows that our method can better reduce the noise in complex lighting scenesand improvethe imagequality.
文摘To the Editor:Living donor liver transplantation continues to be a widely ac-cepted treatment for end-stage liver diseases[1].However,biliary complications remain a significant challenge,attributable to both surgical and nonsurgical factors.These complications include bile leakage,biliary stricture,and choledocholithiasis,with a reported incidence of biliary stricture in pediatric living donor liver recip-ients ranging from 10%to 35%[2].Commonly employed thera-peutic approaches for biliary complications are endoscopic retro-grade cholangiopancreatography(ERCP),percutaneous transhepatic cholangioscopic lithotomy(PTCSL),and surgery,with ERCP often being the preferred initial treatment.
基金supported by the Key Research and Development Program,Ministry of Science and Technology of the People’s Republic of China(Nos.2023YFC2606500,2023YFE0206500).
文摘Coronaviruses are single-stranded,positive-sense RNA enveloped viruses that have posed a significant threat to human health over the past few decades,particularly severe acute respiratory syndrome coronavirus(SARS-CoV),Middle East respiratory syndrome coronavirus(MERS-CoV),and SARS-CoV-2.These viruses have caused widespread infections and fatalities,with profound impacts on global economies,social life,and public health systems.Due to their broad host range in natural settings and the consequent high potential for zoonotic spillover events,a thorough investigation of the common viral mechanisms and the identification of druggable targets for pan-coronavirus antiviral development are of utmost importance.
基金supported by the Natural Science Foundation of Beijing Municipality(Grant No.4212003)the Crossdisciplinary Collaboration Project of Beijing Municipal Science and Technology New Star Program(Grant No.202111)。
文摘In the process of launching guided projectile under the conventional system, it is difficult to effectively obtain the precise navigation parameters of the projectile in the high dynamic environment. Aiming at this problem, this paper describes a new system of guided ammunition based on tail spin reduction. After analyzing the mechanism of the ammunition's tail spin reduction, a navigation method of large scale difference tail control simple guided ammunition based on speed constraint is proposed. In this method,the corresponding navigation constraints can be carried out by combining the rotation speed state of the ammunition itself, and the optimal solution of navigation parameters during the flight of the missile can be obtained by Extended Kalman Filter(EKF). Finally, the performance of the proposed method was verified by the simulation environment, and the hardware-in-the-loop simulation test and flight test were carried out to verify the performance of the method in the real environment. The experimental results show that the proposed method can achieve the optimal estimation of navigation parameters for simple guided ammunition with large-scale difference tail control. Under the conditions of simulation test and hardware-in-loop simulation test, the position and velocity errors calculated by the method in this paper converged. Under the condition of flight test, the spatial average error calculated by the method described in this paper is 6.17 m, and the spatial error of the final landing point is 3.50 m.Through this method, the accurate acquisition of navigation parameters in the process of projectile launching is effectively realized.
