Decoupling coefficients of dilatational wave for Biot's dynamic equation and its Green's functions in frequency domain

Green＇s functions for Blot＇s dynamic equation in the frequency domain can be a highly useful tool for the investigation of dynamic responses of a saturated porous medium. Its applications are found in soil dynamics, seismology, earthquake engineering, rock mechanics, geophysics, and acoustics. However, the mathematical work for deriving it can be daunting. Green＇s functions have been presented utilizing an analogy between the dynamic thermoelasticity and the dynamic poroelasticity in the frequency domain using the u-p formulation. In this work, a special term ＂decoupling coefficient＂ for the decomposition of the fast and slow dilatational waves is proposed and expressed to present a new methodology for deriving the poroelastodynamic Green＇s functions. The correct- ness of the solution is demonstrated by numerically comparing the current solution with Cheng＇s previous solution. The separation of the two waves in the present methodology allows the more accurate evaluation of Green＇s functions, particularly the solution of the slow dilatational wave. This can be advantageous for the numerical implementation of the boundary element method （BEM） and other applications.

Analysis of Second-Harmonic Generation of Low-Frequency Dilatational Lamb Waves in a Two-Layered Composite Plate

We analyze the effect of second-harmonic generation（SHG） of primary Lamb wave propagation in a two-layered composite plate, and then investigate the influence of interfacial properties on the said effect at low frequency. It is found that changes in the interfacial properties essentially affect the dispersion relation and then the maximum cumulative distance of the double-frequency Lamb wave generated. This will remarkably influence the efficiency of SHG. To overcome the complications arising from the inherent dispersion and multimode natures in analyzing the SHG effect of Lamb waves, the present work focuses on the analysis of the SHG effect of low-frequency dilatational Lamb wave propagation. Both the numerical analysis and finite element simulation indicate that the SHG effect of low-frequency dilatational Lamb wave propagation is found to be much more sensitive to changes in the interfacial properties than primary Lamb waves. The potential of using the SHG effect of low-frequency dilatational Lamb waves to characterize a minor change in the interfacial properties is analyzed.

THE ELASTIC FIELD CASED BY TWO INCLUSIONS WITH UNI- FORM DILATATIONAL EIGENSTRAINS IN DISSIMILAR MEDIA

The displacement and the stress states cased by single inclusion are achieved from the fundamental solutions such as nuclei of strain in bimaterals. The elastic field induced by multiple inclusions in dissimilar media could be found from the superstition of that of individual precipitate. In this paper, the effect of the planner interface with parameters of depth from the interface, both pairs of elastic moduli and also shapes of the inclusion are also given, which are of great significance in physical applications.

超声辅助与纤维支气管镜辅助经皮扩张气管切开术的对比研究

目的探讨超声辅助经皮扩张气管切开术的应用价值。方法回顾性分析2020年12月~2022年12月在甘肃省人民医院重症医学科行经皮扩张气管切开术患者56例,均经口气管插管后呼吸机辅助呼吸,根据不同的辅助方式分为超声辅助(超声组)31例和纤维支气管镜辅助(纤维支气管镜组)25例。结果与纤维支气管镜组比较,超声组术中氧合指数(PaO_(2)/FiO_(2))增高[(157.3±19.2)mmHg vs.(145.4±22.8)mmHg,t=2.117,P=0.039],分钟通气(MV)量增高[(7.3±0.8)L/min vs.(6.1±0.7)L/min,t=5.278,P<0.001],动脉血二氧化碳分压(PCO_(2))降低[(39.1±4.8)mmHgvs.(44.3±5.6)mmHg,t=-3.709,P<0.001],术后出血例数减少[0例vs.4例,χ^(2)=5.246,P=0.022]。结论超声组较纤维支气管镜组行经皮扩张气管切开术手术并发症少,安全性高。

经鼓室口咽鼓管球囊扩张术的疗效及咽鼓管功能的影响

目的探讨经鼓室口咽鼓管球囊扩张(balloon dilatation Eustachian tuboplasty,BET)联合腺样体消融术对慢性分泌性中耳炎(chronic secretory otitis media,CSOM)患儿的疗效及咽鼓管功能的影响。方法选取2020年6月~2022年12月间在中山市小榄人民医院就诊的CSOM患儿82例作为研究对象,采用随机数字表法分为对照组和观察组,每组41例。对照组接受腺样体消融术+鼓膜切开置管术治疗,观察组接受腺样体消融术+鼓膜切开置管术+BET术。比较两组手术相关指标及住院时间、临床症状、咽鼓管功能、临床疗效及随访6个月并发症及复发情况。结果两组术中出血量比较,差异无统计学意义(P>0.05),与对照组相比,观察组手术时间更长,住院时间更短(P<0.05)。与对照组相比,观察组中耳积液消失时间、耳鸣消失时间、鼓膜愈合时间、听力恢复时间均更短(P<0.05)。与治疗前相比,治疗后两组咽鼓管评分(Eustachian tube score,ETS)升高、咽鼓管功能障碍评分量表(Eustachian tube dysfunction questionnaire-7,ETDQ-7)评分降低(P<0.05),观察组ETS评分高于对照组,ETDQ-7评分则低于对照组(P<0.05)。观察组临床总有效率高于对照组,差异具有统计学意义(P<0.05)。两组并发症发生率比较,差异无统计学意义(14.63%vs.9.76%,P>0.05),与对照组相比,观察组复发率更低,差异具有统计学意义(21.95%vs.2.44%,P<0.05)。结论经鼓室口BET联合腺样体消融术有助于提高CSOM患儿的临床疗效,改善咽鼓管功能,促进术后恢复,减少复发率,且并发症发生率低。

Failure transition of shear-to-dilation band of rock salt under triaxial stresses

Great potential of underground gas/energy storage in salt caverns seems to be a promising solution to support renewable energy.In the underground storage method,the operating cycle unfortunately may reach up to daily or even hourly,which generates complicated pressures on the salt cavern.Furthermore,the mechanical behavior of rock salt may change and present distinct failure characteristics under different stress states,which affects the performance of salt cavern during the time period of full service.To reproduce a similar loading condition on the cavern surrounding rock mass,the cyclic triaxial loading/unloading tests are performed on the rock salt to explore the mechanical transition behavior and failure characteristics under different confinement.Experimental results show that the rock salt samples pre-sent a diffused shear failure band with significant bulges at certain locations in low confining pressure conditions(e.g.5 MPa,10 MPa and 15 MPa),which is closely related to crystal misorientation and grain boundary sliding.Under the elevated confinement(e.g.20 MPa,30 MPa and 40 MPa),the dilation band dominates the failure mechanism,where the large-size halite crystals are crushed to be smaller size and new pores are developing.The failure transition mechanism revealed in the paper provides additional insight into the mechanical performance of salt caverns influenced by complicated stress states.

Response letter to “Acute cholangitis: Does malignant biliary obstruction vs choledocholithiasis etiology change the outcomes?” with imaging aspects

Radiological imaging findings may contribute to the differentiation of malignant biliary obstruction from choledocholithiasis in the etiology of acute cholangitis.

Percutaneous dilatational tracheostomy for ICU patients with severe brain injury

Objective： To sum up our experience in percutaneous dilatational tracheostomy （PDT） in ICU patient with severe brain injury. Methods： Between November 2011 and April 2014, PDTs were performed on 32 severe brain injury patients in ICU by a team of physicians and intensivists. The success rate, efficacy, safety, and complications including stomal infection and bleeding, paratracheal insertion, pneumothorax, pneumomediastinum, tracheal laceration, as well as clinically significant tracheal stenosis were carefully monitored and recorded respectively. Results： The operations took 4-15 minutes （mean 9.1 minutes±4.2 minutes）. Totally 4 cases suffered from complications in the operations： 3 cases of stomal bleeding, and 1 case of intratracheal bloody secretion, but none required intervention. Paratracheal insertion,pneumothorax, pneumomediastinum, tracheal laceration, or clinically significant tracheal stenosis were not found in PDT patients. There was no procedure-related death occurring during or after PDT. Conclusion： Our study demonstrats that PDT is a safe, highly effective, and minimally invasive procedure. The appropriate sedation and airway management perioperatively help to reduce complication rates. PDT should be performed or supervised by a team of physicians with extensive experience in this procedure, and also an intensivist with experience in difficult airway management.

Thermodynamic prediction of martensitic transformation temperature in Fe-C-X(X=Ni,Mn,Si,Cr)systems with dilatational coefficient model

Martensitic transformation is significant to strengthen steels,but its thermodynamic prediction is restricted to simple systems due to lacking multicomponent interaction parameters.The driving forces of martensitic transformation can be divided into chemical and non-chemical driving forces.The magnetic parameters are carefully optimized because it affects the magnetic Gibbs free energy of austenite and ferrite,and have big impact on the chemical driving force.The dilatational strain energy provides major contribution to non-chemical driving force,thus the integrated-models for dilatational coefficient are constructed in a wide composition and temperature range based on the experimental dilatational data.It expands the scope of application of thermodynamic model and improved prediction accuracy of martensitic transformation temperature(M_(s)).The prediction error reaches 5.6%for Fe-C-X(X=Ni,Mn,Si,Cr)and6.5%for Fe-C-Mn-Si-X(X=Cr,Ni)steels.

Mechanical response and dilatancy characteristics of deep marble under different stress paths:A sight from energy dissipation

Dilatancy is a fundamental volumetric growth behavior observed during loading and serves as a key index to comprehending the intricate nonlinear behavior and constitutive equation structure of rock.This study focuses on Jinping marble obtained from the Jinping Underground Laboratory in China at a depth of 2400 m.Various uniaxial and triaxial tests at different strain rates,along with constant confining pressure tests and reduced confining pressure tests under different confining pressures were conducted to analyze the mechanical response and dilatancy characteristics of the marble under four stress paths.Subsequently,a new empirical dilatancy coefficient is proposed based on the energy dissipation method.The results show that brittle failure characteristics of marble under uniaxial compression are more obvious with the strain rate increasing,and plastic failure characteristics of marble under triaxial compression are gradually strengthened.Furthermore,compared to the constant confining pressure,the volume expansion is relatively lower under unloading condition.The energy dissipation is closely linked to the process of dilatancy,with a rapid increase of dissipated energy coinciding with the beginning of dilatancy.A new empirical dilatancy coefficient is defined according to the change trend of energy dissipation rate curve,of which change trend is consistent with the actual dilatancy response in marble under different stress paths.The existing empirical and theoretical dilatancy models are analyzed,which shows that the empirical dilatancy coefficient based on the energy background is more universal.

Numerical modelling of post-failure behaviors of coal specimens

A modelling approach consisting of best-fit relations to estimate the post-yield strength parameters is presented for simulating post-peak behavior beyond the point of residual strength of coal pillars having different w/h ratios.The model was developed based on back-analysis of the complete stress-strain behavior of specimens belonging to six different Indian coal seams with different w/h ratios of 0.5 e13.5.It was found that the simultaneous degradation of the cohesion and friction angle of the Mohr-Coulomb rock material characterizes the post-peak strength behavior of the rock.The resulting expressions are simplistic as they require parameters that can be easily determined using uniaxial and triaxial compression results.Eventually,the developed model was validated by simulating the triaxial tests of coal specimens with different sizes under varying confining stresses and comparing its findings with the published test results.The study showed that its implementation in the numerical model could reproduce laboratory-observed mechanical response,deformation behavior,and failure mechanism very closely.

Convolution-Transformer for Image Feature Extraction

This study addresses the limitations of Transformer models in image feature extraction,particularly their lack of inductive bias for visual structures.Compared to Convolutional Neural Networks(CNNs),the Transformers are more sensitive to different hyperparameters of optimizers,which leads to a lack of stability and slow convergence.To tackle these challenges,we propose the Convolution-based Efficient Transformer Image Feature Extraction Network(CEFormer)as an enhancement of the Transformer architecture.Our model incorporates E-Attention,depthwise separable convolution,and dilated convolution to introduce crucial inductive biases,such as translation invariance,locality,and scale invariance,into the Transformer framework.Additionally,we implement a lightweight convolution module to process the input images,resulting in faster convergence and improved stability.This results in an efficient convolution combined Transformer image feature extraction network.Experimental results on the ImageNet1k Top-1 dataset demonstrate that the proposed network achieves better accuracy while maintaining high computational speed.It achieves up to 85.0%accuracy across various model sizes on image classification,outperforming various baseline models.When integrated into the Mask Region-ConvolutionalNeuralNetwork(R-CNN)framework as a backbone network,CEFormer outperforms other models and achieves the highest mean Average Precision(mAP)scores.This research presents a significant advancement in Transformer-based image feature extraction,balancing performance and computational efficiency.

TSCND:Temporal Subsequence-Based Convolutional Network with Difference for Time Series Forecasting

Time series forecasting plays an important role in various fields, such as energy, finance, transport, and weather. Temporal convolutional networks (TCNs) based on dilated causal convolution have been widely used in time series forecasting. However, two problems weaken the performance of TCNs. One is that in dilated casual convolution, causal convolution leads to the receptive fields of outputs being concentrated in the earlier part of the input sequence, whereas the recent input information will be severely lost. The other is that the distribution shift problem in time series has not been adequately solved. To address the first problem, we propose a subsequence-based dilated convolution method (SDC). By using multiple convolutional filters to convolve elements of neighboring subsequences, the method extracts temporal features from a growing receptive field via a growing subsequence rather than a single element. Ultimately, the receptive field of each output element can cover the whole input sequence. To address the second problem, we propose a difference and compensation method (DCM). The method reduces the discrepancies between and within the input sequences by difference operations and then compensates the outputs for the information lost due to difference operations. Based on SDC and DCM, we further construct a temporal subsequence-based convolutional network with difference (TSCND) for time series forecasting. The experimental results show that TSCND can reduce prediction mean squared error by 7.3% and save runtime, compared with state-of-the-art models and vanilla TCN.

Dilation,discrimination and Uhlmann's theorem of link products of quantum channels

We establish the Stinespring dilation theorem of the link product of quantum channels in two different ways,discuss the discrimination of quantum channels,and show that the distinguishability can be improved by self-linking each quantum channel n times as n grows.We also find that the maximum value of Uhlmann's theorem can be achieved for diagonal channels.

An improved deep dilated convolutional neural network for seismic facies interpretation

With the successful application and breakthrough of deep learning technology in image segmentation,there has been continuous development in the field of seismic facies interpretation using convolutional neural networks.These intelligent and automated methods significantly reduce manual labor,particularly in the laborious task of manually labeling seismic facies.However,the extensive demand for training data imposes limitations on their wider application.To overcome this challenge,we adopt the UNet architecture as the foundational network structure for seismic facies classification,which has demonstrated effective segmentation results even with small-sample training data.Additionally,we integrate spatial pyramid pooling and dilated convolution modules into the network architecture to enhance the perception of spatial information across a broader range.The seismic facies classification test on the public data from the F3 block verifies the superior performance of our proposed improved network structure in delineating seismic facies boundaries.Comparative analysis against the traditional UNet model reveals that our method achieves more accurate predictive classification results,as evidenced by various evaluation metrics for image segmentation.Obviously,the classification accuracy reaches an impressive 96%.Furthermore,the results of seismic facies classification in the seismic slice dimension provide further confirmation of the superior performance of our proposed method,which accurately defines the range of different seismic facies.This approach holds significant potential for analyzing geological patterns and extracting valuable depositional information.

Gastroesophageal reflux following peroral endoscopic myotomy for achalasia:Bumps in the road to success

Achalasia can significantly impair the quality of life.The clinical presentation typically includes dysphagia to both solids and liquids,chest pain,and regurgitation.Diagnosis can be delayed in patients with atypical presentations,and they might receive a wrong diagnosis,such as gastroesophageal reflux disease(GERD),owing to overlapping symptoms of both disorders.Although the cause of achalasia is poorly understood,its impact on the motility of the esophagus and gastroesophageal junction is well established.Several treatment modalities have been utilized,with the most common being surgical Heller myotomy with concomitant fundoplication and pneumatic balloon dilatation.Recently,peroral endoscopic myotomy(POEM)has gained popularity as an effective treatment for achalasia,despite a relatively high incidence of GERD occurring after treatment compared to other modalities.The magnitude of post-POEM GERD depends on its definition and is influenced by patient and procedure-related factors.The longterm sequelae of post-POEM GERD are yet to be determined,but it appears to have a benign course and is usually manageable with clinically available modalities.Identifying risk factors for post-POEM GERD and modifying the POEM procedure in selected patients may improve the overall success of this technique.

KGTLIR:An Air Target Intention Recognition Model Based on Knowledge Graph and Deep Learning

As a core part of battlefield situational awareness,air target intention recognition plays an important role in modern air operations.Aiming at the problems of insufficient feature extraction and misclassification in intention recognition,this paper designs an air target intention recognition method(KGTLIR)based on Knowledge Graph and Deep Learning.Firstly,the intention recognition model based on Deep Learning is constructed to mine the temporal relationship of intention features using dilated causal convolution and the spatial relationship of intention features using a graph attention mechanism.Meanwhile,the accuracy,recall,and F1-score after iteration are introduced to dynamically adjust the sample weights to reduce the probability of misclassification.After that,an intention recognition model based on Knowledge Graph is constructed to predict the probability of the occurrence of different intentions of the target.Finally,the results of the two models are fused by evidence theory to obtain the target’s operational intention.Experiments show that the intention recognition accuracy of the KGTLIRmodel can reach 98.48%,which is not only better than most of the air target intention recognition methods,but also demonstrates better interpretability and trustworthiness.

Preliminary exploration of animal models of congenital choledochal cysts

BACKGROUND Various animal models have been used to explore the pathogenesis of choledochal cysts(CCs),but with little convincing results.Current surgical techniques can achieve satisfactory outcomes for treatment of CCs.Consequently,recent studies have focused more on clinical issues rather than basic research.Therefore,we need appropriate animal models to further basic research.AIM To establish an appropriate animal model that may contribute to the investigation of the pathogenesis of CCs.METHODS Eighty-four specific pathogen-free female Sprague-Dawley rats were randomly allocated to a surgical group,sham surgical group,or control group.A rat model of CC was established by partial ligation of the bile duct.The reliability of the model was confirmed by measurements of serum biochemical indices,morpho-logy of common bile ducts of the rats as well as molecular biology experiments in rat and human tissues.RESULTS Dilation classified as mild(diameter,≥1 mm to<3 mm),moderate(≥3 mm to<10 mm),and severe(≥10 mm)was observed in 17,17,and 2 rats in the surgical group,respectively,while no dilation was observed in the control and sham surgical groups.Serum levels of alanine aminotransferase,aspartate aminotrans-ferase,total bilirubin,direct bilirubin,and total bile acids were significantly elevated in the surgical group as compared to the control group 7 d after surgery,while direct bilirubin,total bilirubin,and gamma-glutamyltransferase were further increased 14 d after surgery.Most of the biochemical indices gradually decreased to normal ranges 28 d after surgery.The protein expression trend of signal transducer and activator of transcription 3 in rat model was consistent with the human CC tissues.CONCLUSION The model of partial ligation of the bile duct of juvenile rats could morphologically simulate the cystic or fusiform CC,which may contribute to investigating the pathogenesis of CC.

Polyneuropathy, organomegaly, endocrinopathy, M-protein, skin changes syndrome with dilated cardiomyopathy: A case report

BACKGROUND Polyneuropathy,organomegaly,endocrinopathy,M-protein,skin changes(POEMS)syndrome is a rare paraneoplastic syndrome that encompass multiple systems.The most common clinical symptoms of POEMS syndrome are pro-gressive sensorimotor polyneuropathy,organ enlargement,endocrine disorders,darkening skin,a monoclonal plasma cell proliferative disorder,and lymph node hyperplasia.The organomegaly consists of hepatosplenomegaly and/or lym-phadenopathy;cases of cardiomyopathy are rare.Diagnoses are often delayed because of the atypical nature of the syndrome,exposing patients to possibly severe disability.Therefore,identifying atypical symptoms can improve the prognosis and quality of life among POEMS syndrome patients.lenalidomide and dexamethasone.CONCLUSION When patients with cardiomyopathy have systemic manifestations such as numb limbs and darkening skin,the POEMS syndrome is the most possible diagnosis.

Assessing the range of blasting-induced cracks in the surrounding rock of deeply buried tunnels based on the unified strength theory

Blasting-induced cracks in the rock surrounding deeply buried tunnels can result in water gushing and rock mass collapse,posing significant safety risks.However,previous theoretical studies on the range of blasting-induced cracks often ignore the impact of the in-situ stress,especially that of the intermediate principal stress.The particle displacement−crack radius relationship was established in this paper by utilizing the blasthole cavity expansion equation,and theoretical analytical formulas of the stress−displacement relationship and the crack radius were derived with unified strength theory to accurately assess the range of cracks in deep surrounding rock under a blasting load.Parameter analysis showed that the crushing zone size was positively correlated with in-situ stress,intermediate principal stress,and detonation pressure,whereas negatively correlated with Poisson ratio and decoupling coefficient.The dilatancy angle-crushing zone size relationship exhibited nonmonotonic behavior.The relationships in the crushing zone and the fracture zone exhibited opposite trends under the influence of only in-situ stress or intermediate principal stress.As the in-situ stress increased from 0 to 70 MPa,the rate of change in the crack range and the attenuation rate of the peak vibration velocity gradually slowed.