BACKGROUND The discrepancy between endoscopic biopsy pathology and the overall pathology of gastric low-grade intraepithelial neoplasia(LGIN)presents challenges in developing diagnostic and treatment protocols.AIM To ...BACKGROUND The discrepancy between endoscopic biopsy pathology and the overall pathology of gastric low-grade intraepithelial neoplasia(LGIN)presents challenges in developing diagnostic and treatment protocols.AIM To develop a risk prediction model for the pathological upgrading of gastric LGIN to aid clinical diagnosis and treatment.METHODS We retrospectively analyzed data from patients newly diagnosed with gastric LGIN who underwent complete endoscopic resection within 6 months at the First Medical Center of Chinese People’s Liberation Army General Hospital between January 2008 and December 2023.A risk prediction model for the pathological progression of gastric LGIN was constructed and evaluated for accuracy and clinical applicability.RESULTS A total of 171 patients were included in this study:93 patients with high-grade intraepithelial neoplasia or early gastric cancer and 78 with LGIN.The logistic stepwise regression model demonstrated a sensitivity and specificity of 0.868 and 0.800,respectively,while the least absolute shrinkage and selection operator(LASSO)regression model showed sensitivity and specificity values of 0.842 and 0.840,respectively.The area under the curve(AUC)for the logistic model was 0.896,slightly lower than the AUC of 0.904 for the LASSO model.Internal validation with 30%of the data yielded AUC scores of 0.908 for the logistic model and 0.905 for the LASSO model.The LASSO model provided greater utility in clinical decision-making.CONCLUSION A risk prediction model for the pathological upgrading of gastric LGIN based on white-light and magnifying endoscopic features can accurately and effectively guide clinical diagnosis and treatment.展开更多
The isolated fracture-vug systems controlled by small-scale strike-slip faults within ultra-deep carbonate rocks of the Tarim Basin exhibit significant exploration potential.The study employs a novel training set inco...The isolated fracture-vug systems controlled by small-scale strike-slip faults within ultra-deep carbonate rocks of the Tarim Basin exhibit significant exploration potential.The study employs a novel training set incorporating innovative fault labels to train a U-Net-structured CNN model,enabling effective identification of small-scale strike-slip faults through seismic data interpretation.Based on the CNN faults,we analyze the distribution patterns of small-scale strike-slip faults.The small-scale strike-slip faults can be categorized into NNW-trending and NE-trending groups with strike lengths ranging 200–5000 m.The development intensity of small-scale strike-slip faults in the Lower Yingshan Member notably exceeds that in the Upper Member.The Lower and Upper Yingshan members are two distinct mechanical layers with contrasting brittleness characteristics,separated by a low-brittleness layer.The superior brittleness of the Lower Yingshan Member enhances the development intensity of small-scale strike-slip faults compared to the upper member,while the low-brittleness layer exerts restrictive effects on vertical fault propagation.Fracture-vug systems formed by interactions of two or more small-scale strike-slip faults demonstrate larger sizes than those controlled by individual faults.All fracture-vug system sizes show positive correlations with the vertical extents of associated small-scale strike-slip faults,particularly intersection and approaching fracture-vug systems exhibit accelerated size increases proportional to the vertical extents.展开更多
The three-dimensional(3D)geometry of a fault is a critical control on earthquake nucleation,dynamic rupture,stress triggering,and related seismic hazards.Therefore,a 3D model of an active fault can significantly impro...The three-dimensional(3D)geometry of a fault is a critical control on earthquake nucleation,dynamic rupture,stress triggering,and related seismic hazards.Therefore,a 3D model of an active fault can significantly improve our understanding of seismogenesis and our ability to evaluate seismic hazards.Utilising the SKUA GoCAD software,we constructed detailed seismic fault models for the 2021 M_(S)6.4 Yangbi earthquake in Yunnan,China,using two sets of relocated earthquake catalogs and focal mechanism solutions following a convenient 3D fault modeling workflow.Our analysis revealed a NW-striking main fault with a high-angle SW dip,accompanied by two branch faults.Interpretation of one dataset revealed a single NNW-striking branch fault SW of the main fault,whereas the other dataset indicated four steep NNE-striking segments with a left-echelon pattern.Additionally,a third ENE-striking short fault was identified NE of the main fault.In combination with the spatial distribution of pre-existing faults,our 3D fault models indicate that the Yangbi earthquake reactivated pre-existing NW-and NE-striking fault directions rather than the surface-exposed Weixi-Qiaohou-Weishan Fault zone.The occurrence of the Yangbi earthquake demonstrates that the reactivation of pre-existing faults away from active fault zones,through either cascade or conjugate rupture modes,can cause unexpected moderate-large earthquakes and severe disasters,necessitating attention in regions like southeast Xizang,which have complex fault systems.展开更多
Superconducting radio-frequency(SRF)cavities are the core components of SRF linear accelerators,making their stable operation considerably important.However,the operational experience from different accelerator labora...Superconducting radio-frequency(SRF)cavities are the core components of SRF linear accelerators,making their stable operation considerably important.However,the operational experience from different accelerator laboratories has revealed that SRF faults are the leading cause of short machine downtime trips.When a cavity fault occurs,system experts analyze the time-series data recorded by low-level RF systems and identify the fault type.However,this requires expertise and intuition,posing a major challenge for control-room operators.Here,we propose an expert feature-based machine learning model for automating SRF cavity fault recognition.The main challenge in converting the"expert reasoning"process for SRF faults into a"model inference"process lies in feature extraction,which is attributed to the associated multidimensional and complex time-series waveforms.Existing autoregression-based feature-extraction methods require the signal to be stable and autocorrelated,resulting in difficulty in capturing the abrupt features that exist in several SRF failure patterns.To address these issues,we introduce expertise into the classification model through reasonable feature engineering.We demonstrate the feasibility of this method using the SRF cavity of the China accelerator facility for superheavy elements(CAFE2).Although specific faults in SRF cavities may vary across different accelerators,similarities exist in the RF signals.Therefore,this study provides valuable guidance for fault analysis of the entire SRF community.展开更多
The frontal edge of the Makran accretionary wedge is characterized by the development of multiple imbricate thrust faults trending E-W and relatively parallel.However,the mechanisms underlying their formation and the ...The frontal edge of the Makran accretionary wedge is characterized by the development of multiple imbricate thrust faults trending E-W and relatively parallel.However,the mechanisms underlying their formation and the factors controlling their development remain subjects of debate.This paper,based on seismic profile analysis,employs physical simulation experiments to establish a'wedge'type subduction model.The study explores the influence of the initial wedge angle,horizontal sand layer thickness,and the presence or absence of a decollement layer on the structural styles of the thrust wedge.Experimental results indicate that as the initial wedge angle decreases from 11°to 8°,the lateral growth of the thrust wedge increases,whereas vertical growth diminishes.When the horizontal sand layer thickness is reduced from 4.5 cm to 3.0 cm,the spacing between the frontal thrusts decreases and the number of thrust faults increases.Both lateral and vertical growth are relatively reduced,resulting in a smaller thrust wedge.When a decollement layer is present,the structural style exhibits layered deformation.The decollement layer constrains the development of back thrusts and promotes the localized formation of frontal thrusts.In conclusion,the imbricate thrust faults at the frontal edge of the Makran accretionary wedge are primarily controlled by the characteristics of the wedge itself and the presence of the decollement layer.展开更多
1.Introduction The strength of metallic materials can be ameliorated by introducing boundaries,precipitates,or defects as obstacles to dislocation movement[1].However,high strength is generally obtained at the sacrifi...1.Introduction The strength of metallic materials can be ameliorated by introducing boundaries,precipitates,or defects as obstacles to dislocation movement[1].However,high strength is generally obtained at the sacrifice of plastic deformation capability[2].Lately,many strategies have been proposed to improve the comprehensive properties of materials,among which manipulating stacking fault energy(SFE)is effective[3–5].展开更多
Taking the Wangfu fault depression in the Songliao Basin as an example,on the basis of seismic interpretation and drilling data analysis,the distribution of the basement faults was clarified,the fault activity periods...Taking the Wangfu fault depression in the Songliao Basin as an example,on the basis of seismic interpretation and drilling data analysis,the distribution of the basement faults was clarified,the fault activity periods of the coal-bearing formations were determined,and the fault systems were divided.Combined with the coal seam thickness and actual gas indication in logging,the controls of fault systems in the rift basin on the spatial distribution of coal and the occurrence of coal-rock gas were identified.The results show that the Wangfu fault depression is an asymmetrical graben formed under the control of basement reactivated strike-slip T-rupture,and contains coal-bearing formations and five sub-types of fault systems under three types.The horizontal extension strength,vertical activity strength and tectono-sedimentary filling difference of basement faults control vertical stratigraphic sequences,accumulation intensity,and accumulation frequency of coal seam in rift basin.The structural transfer zone formed during the segmented reactivation and growth of the basement faults controls the injection location of steep slope exogenous clasts.The filling effect induced by igneous intrusion accelerates the sediment filling process in the rift lacustrine area.The structural transfer zone and igneous intrusion together determine the preferential accumulation location of coal seams in the plane.The faults reactivated at the basement and newly formed during the rifting phase serve as pathways connecting to the gas source,affecting the enrichment degree of coal-rock gas.The vertical sealing of the faults was evaluated by using shale smear factor(SSF),and the evaluation criterion was established.It is indicated that the SSF is below 1.1 in major coal areas,indicating favorable preservation conditions for coal-rock gas.Based on the influence factors such as fault activity,segmentation and sealing,the coal-rock gas accumulation model of rift basin was established.展开更多
Large basins are currently the global focus for geothermal development,with their hydrothermal system being controlled by a variety of factors,such as basement relief and fracture development.Donglihu is located at th...Large basins are currently the global focus for geothermal development,with their hydrothermal system being controlled by a variety of factors,such as basement relief and fracture development.Donglihu is located at the north of the Cangxian uplift in the North China Basin,the concentrated geothermal resource development zone in North China.This study systematically collects temperature logging data and long-term dynamic monitoring of water level and water quality as well as group well tracer test data carried out in this area in recent years,on the basis of which the hydrothermal controlling role of the deep hidden faults is systematically analyzed.The results show that the Cangdong fault communicates with different geothermal reservoirs in the shallow part and plays a specific role in the water-heat channel of the local area.As a result,the high-value area of the geothermal temperature gradient in the sedimentary layer of the Donglihu area is distributed around the Cangdong fault.The geothermal reservoir temperature of the Minghuazhen Formation within the influence of the fault is also significantly higher than the regional average,the hydraulic head of different geothermal reservoirs showing a consistent and synergistic trend.However,the water quality has been stable for many years without any apparent changes.This understanding has a particular significance for further deepening understanding of the geothermal genesis mechanism in sedimentary basins and guiding future geothermal exploration and development in the Donglihu area.展开更多
Natural fractures controlled by faults in ultradeep carbonate strata play substantial roles as both fluid migration channels and storage spaces.However,characterizing the heterogeneous distribution of underground frac...Natural fractures controlled by faults in ultradeep carbonate strata play substantial roles as both fluid migration channels and storage spaces.However,characterizing the heterogeneous distribution of underground fractures within the complex three-dimensional geometry of strike-slip fault zones remains challenging.This study investigates the characteristics of natural fractures controlled by strike-slip faults in the fractured Middle and Lower Ordovician reservoirs of the central and northern Tarim Basin,China.Seismics,cores,and image logs were integrated to quantitatively analyze the intensity and dip angle of natural fractures and findings were verified using published sandbox simulations.The carbonate reservoir contains three main types of natural fractures:tectonic fractures,abnormal high-pressure-related fractures,and stylolites.Strike-slip faults control the distribution and characteristics of tectonic fractures across various scales.Generally,both fracture intensity and porosity exhibit a decreasing trend as the distance from the main fault surface increases.Compared with those in non-stepover zones along a strike-slip fault,natural fractures and faults in stepover zones are more developed along the fault strike,with significantly greater development intensity in central stepover regions than that at its two ends.Furthermore,strike-slip faults influence the dip angles of both natural fractures and secondary faults.The proportion of medium-to-low-dip angle fractures and faults in the stepover zone is greater than that in the non-stepover zone.Additionally,the proportion of medium-to low-dip angle fractures and faults in the middle of the stepover is greater than that at both ends.Therefore,strike-slip fault structures control the dip angle of natural fracture and the heterogeneity of secondary fault and fracture intensity.The linking damage zone in the stepover contains a larger volume of fractured rocks,making it a promising petroleum exploration target.The development of stepovers and the orientation of present-day in-situ stress substantially influence the productivity of fractured reservoirs controlled by strike-slip faults.The analysis in this study reveals that reservoir productivity increases as the angle between the strike-slip fault segment and the maximum horizontal principal stress decreases.This study provides valuable insights for quantitatively evaluating fracture heterogeneity in fractured reservoirs and establishing optimized selection criteria for favorable targets in fault-related fractured reservoirs.展开更多
Background: The low-grade fibromyxoid sarcoma (LGFMS) is an exceptionally uncommon sarcoma that primarily manifests in the extremities or trunk of young adults, presenting as painless lesions. The histological feature...Background: The low-grade fibromyxoid sarcoma (LGFMS) is an exceptionally uncommon sarcoma that primarily manifests in the extremities or trunk of young adults, presenting as painless lesions. The histological features of this tumor are benign, but it exhibits an exceptionally high rate of late recurrence and a significant potential for metastasis. Imaging examinations serve as a crucial method for detecting LGFMS, while the definitive diagnosis relies on histopathological assessment. Currently, the primary treatment modality for this neoplasm is surgical resection. Early aggressive surgery with negative margins is a critical factor in mitigating the risk of tumor recurrence and metastasis. The present study presented a case of LGFMS located in the right thigh. The patient underwent a mass resection procedure following an MRI examination. During the telephone follow-up one year post-surgery, despite the absence of an imaging review, the surgical site demonstrated satisfactory recovery with no reported abnormal symptoms. Case Presentation: The patient, a 31-year-old male, presented to our hospital for evaluation of an asymptomatic mass in his right thigh that was incidentally discovered 13 years ago. The MRI showed a well-defined mass measuring 8.2 cm × 6.8 cm × 9.6 cm in the right thigh. The tumor signals exhibit a mixed pattern, characterized by predominantly isointense and hypointense signals on T1-weighted imaging (T1WI), a central area of hyperintensity on T2-weighted imaging (T2WI), and peripheral circular enhancement observed on contrast-enhanced scans. The patient underwent surgical resection. Microscopically, the mass was composed of intricately interwoven fibrous matrix and a distinct mucoid region. The tumor cells exhibited a distinctive arrangement in a swirling or wheel-like pattern, with minimal variation in their karyotypic characteristics. The immunohistochemical examination revealed diffuse and intense MUC4 positivity in the tumor cells. The diagnosis of LGFMS was confirmed by post-operative histopathological examination. Conclusions: The LGFMS is an exceptionally uncommon mesenchymal tumor renowned for its benign histological manifestations and malignant behavior. It is crucial to provide a comprehensive summary of the research findings and thoroughly review the existing literature pertaining to this rare disease.展开更多
Bioleaching is confronted with problems,such as low efficiency,long production cycle length,and vegetation destruction.In order to solve problems above,fly ash and low-grade copper sulfide ores were used to investigat...Bioleaching is confronted with problems,such as low efficiency,long production cycle length,and vegetation destruction.In order to solve problems above,fly ash and low-grade copper sulfide ores were used to investigate bioleaching behaviors and bacterial community succession.Results showed that copper recovery,bacterial concentration,total proportion of main leaching bacteria including Acidithiobacillus ferrooxidans,Acidibacillus ferrooxidans,and Leptospirillum ferriphilum,were improved through using appropriate dosage of fly ash.The maximum copper recovery of 79.87%and bacterial concentration of 7.08×10^(7)cells·mL^(-1)were obtained after us-ing 0.8 g·L^(-1)fly ash.Exclusive precipitation including Zn(Fe_(3)(SO_(4))_(2)(OH)_(6))_(2)and Mg(Fe_(3)(SO_(4))_(2)(OH)_(6))_(2)was found in sample added 0.8 g·L^(-1)fly ash,which reduced the effect of hazardous ions on bacteria and thus contributing to bacterial proliferation.Bacterial com-munity structure was differentiated,which indicated difference between original inoculation and sample used 0.8 g·L^(-1)fly ash was less than others.Total proportion of the three microorganism above accounted for more than 95%in all tests,especially in sample with 0.8 g·L^(-1)fly ash up to 99.81%.Cl^(-)and Ag^(+)contained in fly ash can act as catalytic agent,which contributed to conversion from smooth and dense passivation layer to sparse and scattered one,and therefore improving contact between ores,lixiviant,and bacteria.Using appropri-ate dosage of fly ash showed prospects in bioleaching.展开更多
Renewable energy storage technologies are critical for transitioning to sustainable energy systems,with salt caverns playing a significant role in large-scale solutions.In water-soluble mining of low-grade salt format...Renewable energy storage technologies are critical for transitioning to sustainable energy systems,with salt caverns playing a significant role in large-scale solutions.In water-soluble mining of low-grade salt formations,insoluble impurities and interlayers detach during salt dissolution and accumulate as sediment at the cavern base,thereby reducing the storage capacity and economic viability of salt cavern gas storage(SCGS).This study investigates sediment formation mechanisms,void distribution,and voidage in the Huai'an low-grade salt mine,introducing a novel self-developed physical simulation device for two butted-well horizontal(TWH)caverns that replicates compressed air injection and brine discharge.Experiments comparing“one injection and one discharge”and“two injections and one discharge”modes revealed that(1)compressed air effectively displaces brine from sediment voids,(2)a 0.5 MPa injection pressure corresponds to a 10.3 MPa operational lower limit in practice,aligning with field data,and(3)sediment voidage is approximately 46%,validated via air-brine interface theory.The“two injections and one discharge”mode outperformed in both discharge volume and rate.Additionally,a mathematical model for brine displacement via compressed air was established.These results provide foundational insights for optimizing compressed air energy storage(CAES)in low-grade salt mines,advancing their role in renewable energy integration.展开更多
Riedel shear system,which consists of some different oriented faults and derivative structures,is an important pattern of tectonic activity and stress regulation,which has been widely applied to the interpretation of ...Riedel shear system,which consists of some different oriented faults and derivative structures,is an important pattern of tectonic activity and stress regulation,which has been widely applied to the interpretation of intracontinental deformation.The Laolongwan Basin,located in the western Haiyuan fault zone at the northeastern Tibetan Plateau,is a key area to study the Cenozoic intracontinental deformation in the northeastern plateau,which formed a complex active fault system during the Cenozoic.However,the activity of these faults and their kinematic mechanism remain unclear.In this contribution,based on detailed structural interpretation of remote sensing image,field observations and OSL dating analysis,we propose a Riedel Shear model of active fault system in the Laolongwan Basin.Our observations show that this active fault system consist of four major faults,including the left strike-slip Hasi Shan fault and Zihong Shan fault with thrusting characteristics,the Southern Zihong Shan thrust fault and the Mijia Shan normal fault.The fault offset and OSL dating analyses suggest that the left-lateral slip rate of the Hasi Shan fault is~2.60-3.01 mm/a since ca.15 ka,whereas the Zihong Shan fault is~1.10-1.13 mm/a since ca.14 ka.Faultslip vectors analyses indicate that the active fault system related to the Riedel Shear in the Laolongwan Basin was controlled by the regional ENE-WSW compressive stress.This compression also caused the significant left-lateral strike-slip movement along the Haiyuan fault zone at the same time,which might result from the northeastward continuous expanding of the Tibetan Plateau during the Late Cenozoic.展开更多
BACKGROUND Low-grade appendiceal mucinous neoplasms(LAMNs)are a class of histolo-gically well-differentiated adenomas that can proliferate outside the appendix in the form of malignant tumours,resulting in the accumul...BACKGROUND Low-grade appendiceal mucinous neoplasms(LAMNs)are a class of histolo-gically well-differentiated adenomas that can proliferate outside the appendix in the form of malignant tumours,resulting in the accumulation of external appen-diceal mucus.They may present as an extra-appendiceal mass-like bulge,mucus or polypoid tissue at the appendiceal orifice,or even with abdominal dissem-ination.The surgical approach is usually appendectomy,ileocecal resection or right hemicolectomy.It is essential to raise awareness of LAMNs and choose an appropriate treatment.CASE SUMMARY A 68-year-old man underwent a routine physical examination at our hospital on May 17,2022.The patient had no symptoms of abdominal pain,bloating,or weight loss,and his tumour marker levels were normal.The faecal occult blood test was negative,and no abnormalities were identified on physical examination.Colonoscopy revealed a submucosal protrusion at the appendiceal orifice.During endoscopic ultrasound,uneven echoes were observed in the appendix cavity.A contrast-enhanced computed tomography scan of the abdomen revealed a nodular thickening at the base of the appendix,with a diameter of approximately 1 cm.When all the examination results were considered,we suspected the lesion to be an appendiceal mucinous tumour.Laparoscopic surgery was performed using the double purse-string suture method.Postoperative pathology suggested a low-grade mucinous cystadenoma of the appendix with no involvement of the margins.A repeat colonoscopy 18 months after surgery revealed no significant abnormality at the appendiceal orifice.A contrast-enhanced computed tomography scan of the abdomen suggested only postoperative changes.CONCLUSION This study describes a case of LAMN that was treated by resecting the mass at the appendiceal orifice via the double purse-string suture technique and provides new insights on the diagnosis and treatment of LAMNs.展开更多
It is commonly accepted that the formation of oil and gas reservoirs in deep-buried strata is almost impossible due to the huge compaction of in-situ crustal stresses.Nevertheless,recent hydrocarbon explorations in th...It is commonly accepted that the formation of oil and gas reservoirs in deep-buried strata is almost impossible due to the huge compaction of in-situ crustal stresses.Nevertheless,recent hydrocarbon explorations in the Tarim Basin have discovered reservoirs at depths exceeding 8 km.The reservoirs exhibit a strong correlation to the strata’s faults and large fractures,yet the precise underlying mechanical mechanism remains obscure.To illuminate how the faults may facilitate the existence of such deep-buried reservoirs,we consider three ideal scenarios involving unconventional hole-crack interactions under remote biaxial compression.Our focus is on the stress concentration of the hole,influenced by the long main cracks.Closed-form compressive stress solutions are obtained based on our simple theoretical models,showing that long cracks significantly reduce the stress concentration of nearby holes.We quantify the reducing effect of the cracks’angle,surface friction,and pressure on the maximum shear and von Mises stresses around a hole,combining with finite element analysis results.The stress shielding effect is qualitatively consistent with the available experimental observations that the deep-buried caves are often located near the faults and large fractures in carbonate strata.Our results will be beneficial for future exploration of superdeep petroleum reservoirs.展开更多
The operational readiness test(ORT),like weapon testing before firing,is becoming more and more important for systems used in the field.However,the test requirement of the ORT is distinctive.Specifically,the rule of s...The operational readiness test(ORT),like weapon testing before firing,is becoming more and more important for systems used in the field.However,the test requirement of the ORT is distinctive.Specifically,the rule of selecting test items should be changed in different test turns,and whether there is a fault is more important than where the fault is.The popular dependency matrix(D-matrix)processing algorithms becomes low efficient because they cannot change their optimizing direc-tion and spend unnecessary time on fault localization and isola-tion.To this end,this paper proposes a D-matrix processing algorithm named piecewise heuristic algorithm for D-matrix(PHAD).Its key idea is to use a piecewise function comprised of multiple different functions instead of the commonly used fixed function and switch subfunctions according to the test stage.In this manner,PHAD has the capability of changing optimizing direction,precisely matching the variant test requirements,and generating an efficient test sequence.The experiments on the random matrixes of different sizes and densities prove that the proposed algorithm performs better than the classical algo-rithms in terms of expected test cost(ETC)and other metrics.More generally,the piecewise heuristic function shows a new way to design D-matrix processing algorithm and a more flexi-ble heuristic function to meet more complicated test requirements.展开更多
With the increasing demand for high reliability and availability in power conversion equipment within power electronics systems,the fault diagnosis of neutral-point-clamped(NPC) three-level inverters has garnered wide...With the increasing demand for high reliability and availability in power conversion equipment within power electronics systems,the fault diagnosis of neutral-point-clamped(NPC) three-level inverters has garnered widespread attention.To address the challenges of fault feature extraction,this article proposes an end-to-end diagnostic approach based on a wavelet kernel convolutional neural network (WKCNN),capable of extracting multi-scale features from current signals to significantly enhance diagnostic accuracy.This method directly uses raw three-phase current signals as input,applying wavelet kernel convolution to automatically capture frequency-domain fault features,combined with a Softmax classifier optimized by the Adam algorithm to achieve fault diagnosis for NPC threelevel inverters.Experimental results under various operating conditions demonstrate that this approach maintains robust diagnostic accuracy across multiple fault scenarios,with comparative analysis further confirming its advantages in diagnostic efficiency and performance over traditional machine learning and other deep learning methods.展开更多
The electromagnetic pulse valve,as a key component in baghouse dust removal systems,plays a crucial role in the performance of the system.However,despite the promising results of intelligent fault diagnosis methods ba...The electromagnetic pulse valve,as a key component in baghouse dust removal systems,plays a crucial role in the performance of the system.However,despite the promising results of intelligent fault diagnosis methods based on extensive data in diagnosing electromagnetic valves,real-world diagnostic scenarios still face numerous challenges.Collecting fault data for electromagnetic pulse valves is not only time-consuming but also costly,making it difficult to obtain sufficient fault data in advance,which poses challenges for small sample fault diagnosis.To address this issue,this paper proposes a fault diagnosis method for electromagnetic pulse valves based on deep transfer learning and simulated data.This method achieves effective transfer from simulated data to real data through four parameter transfer strategies,which combine parameter freezing and fine-tuning operations.Furthermore,this paper identifies a parameter transfer strategy that simultaneously fine-tunes the feature extractor and classifier,and introduces an attention mechanism to integrate fault features,thereby enhancing the correlation and information complementarity among multi-sensor data.The effectiveness of the proposed method is evaluated through two fault diagnosis cases under different operating conditions.In this study,small sample data accounted for 7.9%and 8.2%of the total dataset,and the experimental results showed transfer accuracies of 93.5%and 94.2%,respectively,validating the reliability and effectiveness of the method under small sample conditions.展开更多
High-density stacking faults(SFs)were introduced into a novel Ni-Co-based superalloy through warm rolling at 300-500°C,and the effects of SFs on its tensile properties at intermediate temperatures(650 and 750...High-density stacking faults(SFs)were introduced into a novel Ni-Co-based superalloy through warm rolling at 300-500°C,and the effects of SFs on its tensile properties at intermediate temperatures(650 and 750°C)were investigated.The results indicated that all warm rolled specimens have high-density SFs and Lomer-Cottrell locks compared with the initial specimens.Meanwhile,the simultaneous improvement of intermediate-temperature strength and ductility of alloys can be achieved by high-density SFs.In particular,the specimen rolled at 300°C exhibited a superior combination of high strength(yield and ultimate tensile strengths of(1311±18)and(1462±25)MPa respectively at 650°C,and(1180±17)and(1293±15)MPa respectively at 750°C)and high fracture elongation((26.7±2.5)%at 650°C and(10.7±1.3)%at 750°C).The high strengths and facture elongations of all warm-rolled specimens were primarily attributed to the interaction of pre-existingγ′phases,high-density SFs and Lomer-Cottrell locks with dislocations,as well as to the formation of high-density deformation nano-twins during tensile loading.展开更多
In this study,we consider a single-link flexible manipulator in the presence of an unknown Bouc-Wen type of hysteresis and intermittent actuator faults.First,an inverse hysteresis dynamics model is introduced,and then...In this study,we consider a single-link flexible manipulator in the presence of an unknown Bouc-Wen type of hysteresis and intermittent actuator faults.First,an inverse hysteresis dynamics model is introduced,and then the control input is divided into an expected input and an error compensator.Second,a novel adaptive neural network-based control scheme is proposed to cancel the unknown input hysteresis.Subsequently,by modifying the adaptive laws and local control laws,a fault-tolerant control strategy is applied to address uncertain intermittent actuator faults in a flexible manipulator system.Through the direct Lyapunov theory,the proposed scheme allows the state errors to asymptotically converge to a specified interval.Finally,the effectiveness of the proposed scheme is verified through numerical simulations and experiments.展开更多
基金Supported by the National Key Research and Development Program of China,No.2022YFC2503600。
文摘BACKGROUND The discrepancy between endoscopic biopsy pathology and the overall pathology of gastric low-grade intraepithelial neoplasia(LGIN)presents challenges in developing diagnostic and treatment protocols.AIM To develop a risk prediction model for the pathological upgrading of gastric LGIN to aid clinical diagnosis and treatment.METHODS We retrospectively analyzed data from patients newly diagnosed with gastric LGIN who underwent complete endoscopic resection within 6 months at the First Medical Center of Chinese People’s Liberation Army General Hospital between January 2008 and December 2023.A risk prediction model for the pathological progression of gastric LGIN was constructed and evaluated for accuracy and clinical applicability.RESULTS A total of 171 patients were included in this study:93 patients with high-grade intraepithelial neoplasia or early gastric cancer and 78 with LGIN.The logistic stepwise regression model demonstrated a sensitivity and specificity of 0.868 and 0.800,respectively,while the least absolute shrinkage and selection operator(LASSO)regression model showed sensitivity and specificity values of 0.842 and 0.840,respectively.The area under the curve(AUC)for the logistic model was 0.896,slightly lower than the AUC of 0.904 for the LASSO model.Internal validation with 30%of the data yielded AUC scores of 0.908 for the logistic model and 0.905 for the LASSO model.The LASSO model provided greater utility in clinical decision-making.CONCLUSION A risk prediction model for the pathological upgrading of gastric LGIN based on white-light and magnifying endoscopic features can accurately and effectively guide clinical diagnosis and treatment.
基金supported by the National Natural Science Foundation of China(No.U21B2062).
文摘The isolated fracture-vug systems controlled by small-scale strike-slip faults within ultra-deep carbonate rocks of the Tarim Basin exhibit significant exploration potential.The study employs a novel training set incorporating innovative fault labels to train a U-Net-structured CNN model,enabling effective identification of small-scale strike-slip faults through seismic data interpretation.Based on the CNN faults,we analyze the distribution patterns of small-scale strike-slip faults.The small-scale strike-slip faults can be categorized into NNW-trending and NE-trending groups with strike lengths ranging 200–5000 m.The development intensity of small-scale strike-slip faults in the Lower Yingshan Member notably exceeds that in the Upper Member.The Lower and Upper Yingshan members are two distinct mechanical layers with contrasting brittleness characteristics,separated by a low-brittleness layer.The superior brittleness of the Lower Yingshan Member enhances the development intensity of small-scale strike-slip faults compared to the upper member,while the low-brittleness layer exerts restrictive effects on vertical fault propagation.Fracture-vug systems formed by interactions of two or more small-scale strike-slip faults demonstrate larger sizes than those controlled by individual faults.All fracture-vug system sizes show positive correlations with the vertical extents of associated small-scale strike-slip faults,particularly intersection and approaching fracture-vug systems exhibit accelerated size increases proportional to the vertical extents.
基金financial support from the National Key R&D Program of China (No. 2021YFC3000600)National Natural Science Foundation of China (No. 41872206)National Nonprofit Fundamental Research Grant of China, Institute of Geology, China, Earthquake Administration (No. IGCEA2010)
文摘The three-dimensional(3D)geometry of a fault is a critical control on earthquake nucleation,dynamic rupture,stress triggering,and related seismic hazards.Therefore,a 3D model of an active fault can significantly improve our understanding of seismogenesis and our ability to evaluate seismic hazards.Utilising the SKUA GoCAD software,we constructed detailed seismic fault models for the 2021 M_(S)6.4 Yangbi earthquake in Yunnan,China,using two sets of relocated earthquake catalogs and focal mechanism solutions following a convenient 3D fault modeling workflow.Our analysis revealed a NW-striking main fault with a high-angle SW dip,accompanied by two branch faults.Interpretation of one dataset revealed a single NNW-striking branch fault SW of the main fault,whereas the other dataset indicated four steep NNE-striking segments with a left-echelon pattern.Additionally,a third ENE-striking short fault was identified NE of the main fault.In combination with the spatial distribution of pre-existing faults,our 3D fault models indicate that the Yangbi earthquake reactivated pre-existing NW-and NE-striking fault directions rather than the surface-exposed Weixi-Qiaohou-Weishan Fault zone.The occurrence of the Yangbi earthquake demonstrates that the reactivation of pre-existing faults away from active fault zones,through either cascade or conjugate rupture modes,can cause unexpected moderate-large earthquakes and severe disasters,necessitating attention in regions like southeast Xizang,which have complex fault systems.
基金supported by the studies of intelligent LLRF control algorithms for superconducting RF cavities(No.E129851YR0)the National Natural Science Foundation of China(No.U22A20261)Applications of Artificial Intelligence in the Stability Study of Superconducting Linear Accelerators(No.E429851YR0)。
文摘Superconducting radio-frequency(SRF)cavities are the core components of SRF linear accelerators,making their stable operation considerably important.However,the operational experience from different accelerator laboratories has revealed that SRF faults are the leading cause of short machine downtime trips.When a cavity fault occurs,system experts analyze the time-series data recorded by low-level RF systems and identify the fault type.However,this requires expertise and intuition,posing a major challenge for control-room operators.Here,we propose an expert feature-based machine learning model for automating SRF cavity fault recognition.The main challenge in converting the"expert reasoning"process for SRF faults into a"model inference"process lies in feature extraction,which is attributed to the associated multidimensional and complex time-series waveforms.Existing autoregression-based feature-extraction methods require the signal to be stable and autocorrelated,resulting in difficulty in capturing the abrupt features that exist in several SRF failure patterns.To address these issues,we introduce expertise into the classification model through reasonable feature engineering.We demonstrate the feasibility of this method using the SRF cavity of the China accelerator facility for superheavy elements(CAFE2).Although specific faults in SRF cavities may vary across different accelerators,similarities exist in the RF signals.Therefore,this study provides valuable guidance for fault analysis of the entire SRF community.
基金the National Natural Science Foundation of China(No.42076069)。
文摘The frontal edge of the Makran accretionary wedge is characterized by the development of multiple imbricate thrust faults trending E-W and relatively parallel.However,the mechanisms underlying their formation and the factors controlling their development remain subjects of debate.This paper,based on seismic profile analysis,employs physical simulation experiments to establish a'wedge'type subduction model.The study explores the influence of the initial wedge angle,horizontal sand layer thickness,and the presence or absence of a decollement layer on the structural styles of the thrust wedge.Experimental results indicate that as the initial wedge angle decreases from 11°to 8°,the lateral growth of the thrust wedge increases,whereas vertical growth diminishes.When the horizontal sand layer thickness is reduced from 4.5 cm to 3.0 cm,the spacing between the frontal thrusts decreases and the number of thrust faults increases.Both lateral and vertical growth are relatively reduced,resulting in a smaller thrust wedge.When a decollement layer is present,the structural style exhibits layered deformation.The decollement layer constrains the development of back thrusts and promotes the localized formation of frontal thrusts.In conclusion,the imbricate thrust faults at the frontal edge of the Makran accretionary wedge are primarily controlled by the characteristics of the wedge itself and the presence of the decollement layer.
基金financially supported by the National Natural Science Foundation of China(NSFC)under grant No.52371100.
文摘1.Introduction The strength of metallic materials can be ameliorated by introducing boundaries,precipitates,or defects as obstacles to dislocation movement[1].However,high strength is generally obtained at the sacrifice of plastic deformation capability[2].Lately,many strategies have been proposed to improve the comprehensive properties of materials,among which manipulating stacking fault energy(SFE)is effective[3–5].
基金Supported by the National Natural Science Foundation of China(42472190)Chongqing Natural Science Foundation Innovation and Development Joint Fund Project(CSTB2022NSCQ-LZX0020)Chongqing Talent Innovation and Entrepreneurship Leading Talent Project(0255-19230101042)。
文摘Taking the Wangfu fault depression in the Songliao Basin as an example,on the basis of seismic interpretation and drilling data analysis,the distribution of the basement faults was clarified,the fault activity periods of the coal-bearing formations were determined,and the fault systems were divided.Combined with the coal seam thickness and actual gas indication in logging,the controls of fault systems in the rift basin on the spatial distribution of coal and the occurrence of coal-rock gas were identified.The results show that the Wangfu fault depression is an asymmetrical graben formed under the control of basement reactivated strike-slip T-rupture,and contains coal-bearing formations and five sub-types of fault systems under three types.The horizontal extension strength,vertical activity strength and tectono-sedimentary filling difference of basement faults control vertical stratigraphic sequences,accumulation intensity,and accumulation frequency of coal seam in rift basin.The structural transfer zone formed during the segmented reactivation and growth of the basement faults controls the injection location of steep slope exogenous clasts.The filling effect induced by igneous intrusion accelerates the sediment filling process in the rift lacustrine area.The structural transfer zone and igneous intrusion together determine the preferential accumulation location of coal seams in the plane.The faults reactivated at the basement and newly formed during the rifting phase serve as pathways connecting to the gas source,affecting the enrichment degree of coal-rock gas.The vertical sealing of the faults was evaluated by using shale smear factor(SSF),and the evaluation criterion was established.It is indicated that the SSF is below 1.1 in major coal areas,indicating favorable preservation conditions for coal-rock gas.Based on the influence factors such as fault activity,segmentation and sealing,the coal-rock gas accumulation model of rift basin was established.
基金funded by Public Interest Monitoring Project(No.XCSD-2024-317)of the Tianjin Municipal Bureau of Planning and Natural Resources。
文摘Large basins are currently the global focus for geothermal development,with their hydrothermal system being controlled by a variety of factors,such as basement relief and fracture development.Donglihu is located at the north of the Cangxian uplift in the North China Basin,the concentrated geothermal resource development zone in North China.This study systematically collects temperature logging data and long-term dynamic monitoring of water level and water quality as well as group well tracer test data carried out in this area in recent years,on the basis of which the hydrothermal controlling role of the deep hidden faults is systematically analyzed.The results show that the Cangdong fault communicates with different geothermal reservoirs in the shallow part and plays a specific role in the water-heat channel of the local area.As a result,the high-value area of the geothermal temperature gradient in the sedimentary layer of the Donglihu area is distributed around the Cangdong fault.The geothermal reservoir temperature of the Minghuazhen Formation within the influence of the fault is also significantly higher than the regional average,the hydraulic head of different geothermal reservoirs showing a consistent and synergistic trend.However,the water quality has been stable for many years without any apparent changes.This understanding has a particular significance for further deepening understanding of the geothermal genesis mechanism in sedimentary basins and guiding future geothermal exploration and development in the Donglihu area.
基金supported by the National Natural Science Foundation of China(No.U21B2062)funding from the Chinese Scholarship Council(CSC)and the American Association of Petroleum Geologists Foundation Grantsin-Aid Program.
文摘Natural fractures controlled by faults in ultradeep carbonate strata play substantial roles as both fluid migration channels and storage spaces.However,characterizing the heterogeneous distribution of underground fractures within the complex three-dimensional geometry of strike-slip fault zones remains challenging.This study investigates the characteristics of natural fractures controlled by strike-slip faults in the fractured Middle and Lower Ordovician reservoirs of the central and northern Tarim Basin,China.Seismics,cores,and image logs were integrated to quantitatively analyze the intensity and dip angle of natural fractures and findings were verified using published sandbox simulations.The carbonate reservoir contains three main types of natural fractures:tectonic fractures,abnormal high-pressure-related fractures,and stylolites.Strike-slip faults control the distribution and characteristics of tectonic fractures across various scales.Generally,both fracture intensity and porosity exhibit a decreasing trend as the distance from the main fault surface increases.Compared with those in non-stepover zones along a strike-slip fault,natural fractures and faults in stepover zones are more developed along the fault strike,with significantly greater development intensity in central stepover regions than that at its two ends.Furthermore,strike-slip faults influence the dip angles of both natural fractures and secondary faults.The proportion of medium-to-low-dip angle fractures and faults in the stepover zone is greater than that in the non-stepover zone.Additionally,the proportion of medium-to low-dip angle fractures and faults in the middle of the stepover is greater than that at both ends.Therefore,strike-slip fault structures control the dip angle of natural fracture and the heterogeneity of secondary fault and fracture intensity.The linking damage zone in the stepover contains a larger volume of fractured rocks,making it a promising petroleum exploration target.The development of stepovers and the orientation of present-day in-situ stress substantially influence the productivity of fractured reservoirs controlled by strike-slip faults.The analysis in this study reveals that reservoir productivity increases as the angle between the strike-slip fault segment and the maximum horizontal principal stress decreases.This study provides valuable insights for quantitatively evaluating fracture heterogeneity in fractured reservoirs and establishing optimized selection criteria for favorable targets in fault-related fractured reservoirs.
文摘Background: The low-grade fibromyxoid sarcoma (LGFMS) is an exceptionally uncommon sarcoma that primarily manifests in the extremities or trunk of young adults, presenting as painless lesions. The histological features of this tumor are benign, but it exhibits an exceptionally high rate of late recurrence and a significant potential for metastasis. Imaging examinations serve as a crucial method for detecting LGFMS, while the definitive diagnosis relies on histopathological assessment. Currently, the primary treatment modality for this neoplasm is surgical resection. Early aggressive surgery with negative margins is a critical factor in mitigating the risk of tumor recurrence and metastasis. The present study presented a case of LGFMS located in the right thigh. The patient underwent a mass resection procedure following an MRI examination. During the telephone follow-up one year post-surgery, despite the absence of an imaging review, the surgical site demonstrated satisfactory recovery with no reported abnormal symptoms. Case Presentation: The patient, a 31-year-old male, presented to our hospital for evaluation of an asymptomatic mass in his right thigh that was incidentally discovered 13 years ago. The MRI showed a well-defined mass measuring 8.2 cm × 6.8 cm × 9.6 cm in the right thigh. The tumor signals exhibit a mixed pattern, characterized by predominantly isointense and hypointense signals on T1-weighted imaging (T1WI), a central area of hyperintensity on T2-weighted imaging (T2WI), and peripheral circular enhancement observed on contrast-enhanced scans. The patient underwent surgical resection. Microscopically, the mass was composed of intricately interwoven fibrous matrix and a distinct mucoid region. The tumor cells exhibited a distinctive arrangement in a swirling or wheel-like pattern, with minimal variation in their karyotypic characteristics. The immunohistochemical examination revealed diffuse and intense MUC4 positivity in the tumor cells. The diagnosis of LGFMS was confirmed by post-operative histopathological examination. Conclusions: The LGFMS is an exceptionally uncommon mesenchymal tumor renowned for its benign histological manifestations and malignant behavior. It is crucial to provide a comprehensive summary of the research findings and thoroughly review the existing literature pertaining to this rare disease.
基金supported by China National Postdoctoral Program for Innovative Talents(No.BX20230041)China Postdoctoral Science Foundation(No.2024M750186)+1 种基金the Key Program of National Natural Science Foundation of China(No.52034001)Open Foundation of State Environmental Protection Key Laboratory of Mineral Metallurgical Resources Utilization and Pollution Control(No.HB202303).
文摘Bioleaching is confronted with problems,such as low efficiency,long production cycle length,and vegetation destruction.In order to solve problems above,fly ash and low-grade copper sulfide ores were used to investigate bioleaching behaviors and bacterial community succession.Results showed that copper recovery,bacterial concentration,total proportion of main leaching bacteria including Acidithiobacillus ferrooxidans,Acidibacillus ferrooxidans,and Leptospirillum ferriphilum,were improved through using appropriate dosage of fly ash.The maximum copper recovery of 79.87%and bacterial concentration of 7.08×10^(7)cells·mL^(-1)were obtained after us-ing 0.8 g·L^(-1)fly ash.Exclusive precipitation including Zn(Fe_(3)(SO_(4))_(2)(OH)_(6))_(2)and Mg(Fe_(3)(SO_(4))_(2)(OH)_(6))_(2)was found in sample added 0.8 g·L^(-1)fly ash,which reduced the effect of hazardous ions on bacteria and thus contributing to bacterial proliferation.Bacterial com-munity structure was differentiated,which indicated difference between original inoculation and sample used 0.8 g·L^(-1)fly ash was less than others.Total proportion of the three microorganism above accounted for more than 95%in all tests,especially in sample with 0.8 g·L^(-1)fly ash up to 99.81%.Cl^(-)and Ag^(+)contained in fly ash can act as catalytic agent,which contributed to conversion from smooth and dense passivation layer to sparse and scattered one,and therefore improving contact between ores,lixiviant,and bacteria.Using appropri-ate dosage of fly ash showed prospects in bioleaching.
基金financial support from the National Key Research and Development Program of China(No.2024YFB4007100)the Basic ForwardLooking Project of the Sinopec Science and Technology Department,“Research on the Long-Term Sealing Mechanism of Multi-layer Salt Cavern Hydrogen Storage”(No.P24197-4)。
文摘Renewable energy storage technologies are critical for transitioning to sustainable energy systems,with salt caverns playing a significant role in large-scale solutions.In water-soluble mining of low-grade salt formations,insoluble impurities and interlayers detach during salt dissolution and accumulate as sediment at the cavern base,thereby reducing the storage capacity and economic viability of salt cavern gas storage(SCGS).This study investigates sediment formation mechanisms,void distribution,and voidage in the Huai'an low-grade salt mine,introducing a novel self-developed physical simulation device for two butted-well horizontal(TWH)caverns that replicates compressed air injection and brine discharge.Experiments comparing“one injection and one discharge”and“two injections and one discharge”modes revealed that(1)compressed air effectively displaces brine from sediment voids,(2)a 0.5 MPa injection pressure corresponds to a 10.3 MPa operational lower limit in practice,aligning with field data,and(3)sediment voidage is approximately 46%,validated via air-brine interface theory.The“two injections and one discharge”mode outperformed in both discharge volume and rate.Additionally,a mathematical model for brine displacement via compressed air was established.These results provide foundational insights for optimizing compressed air energy storage(CAES)in low-grade salt mines,advancing their role in renewable energy integration.
基金financially supported by the Natural Science Foundation of Chongqing,China(No.cstc2020jcyj-msxm X0487)the Open Fund of Key Laboratory of Sedimentary Basins and Oil and Gas Resources,the Ministry of Natural Resources(No.cdcgs2022006)+2 种基金the National Natural Science Foundation of China(No.42072001)the China Geological Survey(No.DD20190018)the Science and Technology Innovation Fund for Postgraduates of Chongqing University of Science and Technology(No.YKJCX2220101)。
文摘Riedel shear system,which consists of some different oriented faults and derivative structures,is an important pattern of tectonic activity and stress regulation,which has been widely applied to the interpretation of intracontinental deformation.The Laolongwan Basin,located in the western Haiyuan fault zone at the northeastern Tibetan Plateau,is a key area to study the Cenozoic intracontinental deformation in the northeastern plateau,which formed a complex active fault system during the Cenozoic.However,the activity of these faults and their kinematic mechanism remain unclear.In this contribution,based on detailed structural interpretation of remote sensing image,field observations and OSL dating analysis,we propose a Riedel Shear model of active fault system in the Laolongwan Basin.Our observations show that this active fault system consist of four major faults,including the left strike-slip Hasi Shan fault and Zihong Shan fault with thrusting characteristics,the Southern Zihong Shan thrust fault and the Mijia Shan normal fault.The fault offset and OSL dating analyses suggest that the left-lateral slip rate of the Hasi Shan fault is~2.60-3.01 mm/a since ca.15 ka,whereas the Zihong Shan fault is~1.10-1.13 mm/a since ca.14 ka.Faultslip vectors analyses indicate that the active fault system related to the Riedel Shear in the Laolongwan Basin was controlled by the regional ENE-WSW compressive stress.This compression also caused the significant left-lateral strike-slip movement along the Haiyuan fault zone at the same time,which might result from the northeastward continuous expanding of the Tibetan Plateau during the Late Cenozoic.
基金Supported by Jinhua City Science and Technology Plan Projects“Improve the Polarization of Cancer-related Fatigue:Clinical Efficacy Study”,No.2018-4-049.
文摘BACKGROUND Low-grade appendiceal mucinous neoplasms(LAMNs)are a class of histolo-gically well-differentiated adenomas that can proliferate outside the appendix in the form of malignant tumours,resulting in the accumulation of external appen-diceal mucus.They may present as an extra-appendiceal mass-like bulge,mucus or polypoid tissue at the appendiceal orifice,or even with abdominal dissem-ination.The surgical approach is usually appendectomy,ileocecal resection or right hemicolectomy.It is essential to raise awareness of LAMNs and choose an appropriate treatment.CASE SUMMARY A 68-year-old man underwent a routine physical examination at our hospital on May 17,2022.The patient had no symptoms of abdominal pain,bloating,or weight loss,and his tumour marker levels were normal.The faecal occult blood test was negative,and no abnormalities were identified on physical examination.Colonoscopy revealed a submucosal protrusion at the appendiceal orifice.During endoscopic ultrasound,uneven echoes were observed in the appendix cavity.A contrast-enhanced computed tomography scan of the abdomen revealed a nodular thickening at the base of the appendix,with a diameter of approximately 1 cm.When all the examination results were considered,we suspected the lesion to be an appendiceal mucinous tumour.Laparoscopic surgery was performed using the double purse-string suture method.Postoperative pathology suggested a low-grade mucinous cystadenoma of the appendix with no involvement of the margins.A repeat colonoscopy 18 months after surgery revealed no significant abnormality at the appendiceal orifice.A contrast-enhanced computed tomography scan of the abdomen suggested only postoperative changes.CONCLUSION This study describes a case of LAMN that was treated by resecting the mass at the appendiceal orifice via the double purse-string suture technique and provides new insights on the diagnosis and treatment of LAMNs.
基金supported by the National Natural Science Foundation of China(Grant No.11988102)the Natural Science Foundation of Guangdong Province(Grant No.2019A1515011909)the Science Challenge Project(Grant No.TZ2018002).
文摘It is commonly accepted that the formation of oil and gas reservoirs in deep-buried strata is almost impossible due to the huge compaction of in-situ crustal stresses.Nevertheless,recent hydrocarbon explorations in the Tarim Basin have discovered reservoirs at depths exceeding 8 km.The reservoirs exhibit a strong correlation to the strata’s faults and large fractures,yet the precise underlying mechanical mechanism remains obscure.To illuminate how the faults may facilitate the existence of such deep-buried reservoirs,we consider three ideal scenarios involving unconventional hole-crack interactions under remote biaxial compression.Our focus is on the stress concentration of the hole,influenced by the long main cracks.Closed-form compressive stress solutions are obtained based on our simple theoretical models,showing that long cracks significantly reduce the stress concentration of nearby holes.We quantify the reducing effect of the cracks’angle,surface friction,and pressure on the maximum shear and von Mises stresses around a hole,combining with finite element analysis results.The stress shielding effect is qualitatively consistent with the available experimental observations that the deep-buried caves are often located near the faults and large fractures in carbonate strata.Our results will be beneficial for future exploration of superdeep petroleum reservoirs.
文摘The operational readiness test(ORT),like weapon testing before firing,is becoming more and more important for systems used in the field.However,the test requirement of the ORT is distinctive.Specifically,the rule of selecting test items should be changed in different test turns,and whether there is a fault is more important than where the fault is.The popular dependency matrix(D-matrix)processing algorithms becomes low efficient because they cannot change their optimizing direc-tion and spend unnecessary time on fault localization and isola-tion.To this end,this paper proposes a D-matrix processing algorithm named piecewise heuristic algorithm for D-matrix(PHAD).Its key idea is to use a piecewise function comprised of multiple different functions instead of the commonly used fixed function and switch subfunctions according to the test stage.In this manner,PHAD has the capability of changing optimizing direction,precisely matching the variant test requirements,and generating an efficient test sequence.The experiments on the random matrixes of different sizes and densities prove that the proposed algorithm performs better than the classical algo-rithms in terms of expected test cost(ETC)and other metrics.More generally,the piecewise heuristic function shows a new way to design D-matrix processing algorithm and a more flexi-ble heuristic function to meet more complicated test requirements.
基金supported in part by Zhejiang Provincial“Pioneer”and“Leading Goose”R&D Program of China under Grant 2024C01014the National Natural Science Foundation of China under Grant52177055。
文摘With the increasing demand for high reliability and availability in power conversion equipment within power electronics systems,the fault diagnosis of neutral-point-clamped(NPC) three-level inverters has garnered widespread attention.To address the challenges of fault feature extraction,this article proposes an end-to-end diagnostic approach based on a wavelet kernel convolutional neural network (WKCNN),capable of extracting multi-scale features from current signals to significantly enhance diagnostic accuracy.This method directly uses raw three-phase current signals as input,applying wavelet kernel convolution to automatically capture frequency-domain fault features,combined with a Softmax classifier optimized by the Adam algorithm to achieve fault diagnosis for NPC threelevel inverters.Experimental results under various operating conditions demonstrate that this approach maintains robust diagnostic accuracy across multiple fault scenarios,with comparative analysis further confirming its advantages in diagnostic efficiency and performance over traditional machine learning and other deep learning methods.
基金Supported by National Natural Science Foundation of China(Grant No.51675040)。
文摘The electromagnetic pulse valve,as a key component in baghouse dust removal systems,plays a crucial role in the performance of the system.However,despite the promising results of intelligent fault diagnosis methods based on extensive data in diagnosing electromagnetic valves,real-world diagnostic scenarios still face numerous challenges.Collecting fault data for electromagnetic pulse valves is not only time-consuming but also costly,making it difficult to obtain sufficient fault data in advance,which poses challenges for small sample fault diagnosis.To address this issue,this paper proposes a fault diagnosis method for electromagnetic pulse valves based on deep transfer learning and simulated data.This method achieves effective transfer from simulated data to real data through four parameter transfer strategies,which combine parameter freezing and fine-tuning operations.Furthermore,this paper identifies a parameter transfer strategy that simultaneously fine-tunes the feature extractor and classifier,and introduces an attention mechanism to integrate fault features,thereby enhancing the correlation and information complementarity among multi-sensor data.The effectiveness of the proposed method is evaluated through two fault diagnosis cases under different operating conditions.In this study,small sample data accounted for 7.9%and 8.2%of the total dataset,and the experimental results showed transfer accuracies of 93.5%and 94.2%,respectively,validating the reliability and effectiveness of the method under small sample conditions.
基金supported by the Program for Hong Liu Excellent Young Scholars by Lanzhou University of Technology in 2023,the National Key Research and Development Program of China(No.2017YFA0700703)the Major Science and Technology Project of Gansu Province,China(Nos.22ZD6GA008,23ZDGC002,23ZDGA010)+1 种基金the Gansu Provincial Key Research and Development Program,China(No.20YF3GA041)the Special Fund of National Key Laboratory of Ni&Co Associated Minerals Resources Development and Comprehensive Utilization by Jinchuan Group Co.,Ltd.,China(No.GZSYS-KY-2022-012).
文摘High-density stacking faults(SFs)were introduced into a novel Ni-Co-based superalloy through warm rolling at 300-500°C,and the effects of SFs on its tensile properties at intermediate temperatures(650 and 750°C)were investigated.The results indicated that all warm rolled specimens have high-density SFs and Lomer-Cottrell locks compared with the initial specimens.Meanwhile,the simultaneous improvement of intermediate-temperature strength and ductility of alloys can be achieved by high-density SFs.In particular,the specimen rolled at 300°C exhibited a superior combination of high strength(yield and ultimate tensile strengths of(1311±18)and(1462±25)MPa respectively at 650°C,and(1180±17)and(1293±15)MPa respectively at 750°C)and high fracture elongation((26.7±2.5)%at 650°C and(10.7±1.3)%at 750°C).The high strengths and facture elongations of all warm-rolled specimens were primarily attributed to the interaction of pre-existingγ′phases,high-density SFs and Lomer-Cottrell locks with dislocations,as well as to the formation of high-density deformation nano-twins during tensile loading.
基金supported in part by the National Key Research and Development Program of China(2023YFB4706400)the National Natural Science Foundation of China(62273112,62073030,62203161)+6 种基金the Guangdong Basic and Applied Basic Research Foundation(2023B1515120018,2023B1515120019)the Open Project of Xiangjiang Laboratory(23XJ03012)the Natural Science Foundation of Hunan Province(2024JJ5087)the Natural Science Foundation of Jiangxi Province(20232BAB212024)the National Research Foundation of Korea funded by the Ministry of Science and ICT,South Korea(IRIS-2023-00207954)the Science and Technology Planning Project of Guangzhou,China(2023A03J0120)the Guangzhou University Research Project(RC2023037)
文摘In this study,we consider a single-link flexible manipulator in the presence of an unknown Bouc-Wen type of hysteresis and intermittent actuator faults.First,an inverse hysteresis dynamics model is introduced,and then the control input is divided into an expected input and an error compensator.Second,a novel adaptive neural network-based control scheme is proposed to cancel the unknown input hysteresis.Subsequently,by modifying the adaptive laws and local control laws,a fault-tolerant control strategy is applied to address uncertain intermittent actuator faults in a flexible manipulator system.Through the direct Lyapunov theory,the proposed scheme allows the state errors to asymptotically converge to a specified interval.Finally,the effectiveness of the proposed scheme is verified through numerical simulations and experiments.
