Grain-oriented silicon steels were prepared at different heating rates during high temperature annealing,in which the evolution of magnetic properties,grain orientations and precipitates were studied.To illustrate the...Grain-oriented silicon steels were prepared at different heating rates during high temperature annealing,in which the evolution of magnetic properties,grain orientations and precipitates were studied.To illustrate the Zener factor,the diameter and number density of precipitates of interrupted testing samples were statistically calculated.The effect of precipitate ripening on the Goss texture and magnetic property was investigated.Data indicated that the trend of Zener factor was similar under different heating rates,first increasing and then decreasing,and that the precipitate maturing was greatly inhibited as the heating rate increased.Secondary recrystallization was developed at the temperature of 1010℃when a heating rate of 5℃/h was used,resulting in Goss,Brass and{110}<227>oriented grains growing abnormally and a magnetic induction intensity of 1.90T.Furthermore,increasing the heating rate to 20℃/h would inhibit the development of undesirable oriented grains and obtain a sharp Goss texture.However,when the heating rate was extremely fast,such as 40℃/h,poor secondary recrystallization was developed with many island grains,corresponding to a decrease in magnetic induction intensity to 1.87 T.At a suitable heating rate of 20℃/h,the sharpest Goss texture and the highest magnetic induction of 1.94 T with an onset secondary recrystallization temperature of 1020℃were found among the experimental variables in this study.The heating rate affected the initial temperature of secondary recrystallization by controlling the maturation of precipitates,leading to the deviation and dispersion of Goss texture,thereby reducing the magnetic properties.展开更多
We review the genus Paraglenurus van der Weele,1909 in China,and provide a new Chinese record:P.scopifer(Gerstaeker,1888)from Orchid Island(Lanyu).Additionally,we describe a new species of Paraglenurus from South Viet...We review the genus Paraglenurus van der Weele,1909 in China,and provide a new Chinese record:P.scopifer(Gerstaeker,1888)from Orchid Island(Lanyu).Additionally,we describe a new species of Paraglenurus from South Vietnam,i.e.,P.badanoi sp.nov.,which represents the first record of this genus in Indochina.Furthermore,we confirm that the paratypes of P.pumilus(Yang,1997)are actually a distinct new species in the genus Indophanes Banks,1940,i.e.,I.zhiliangi sp.nov.展开更多
Growth of high-quality Nb_(3)Sn thin films for superconducting radiofrequency(SRF)applications using the vapor diffusion method requires a uniform distribution of tin nuclei on the niobium(Nb)surface.This study examin...Growth of high-quality Nb_(3)Sn thin films for superconducting radiofrequency(SRF)applications using the vapor diffusion method requires a uniform distribution of tin nuclei on the niobium(Nb)surface.This study examines the mechanism underlying the observed non-uniform distribution of tin nuclei with tin chloride SnCl_(2).Electron backscatter diffraction(EBSD)analysis was used to examine the correlation between the nucleation behavior and orientation of niobium grains in the substrate.The findings of the density functional theory(DFT)simulation are in good agreement with the experimental results,showing that the non-uniform distribution of tin nuclei is the result of the adsorption energy of SnCl_(2)molecules by varied niobium grain orientations.Further analysis indicated that the surface roughness and grain size of niobium also played significant roles in the nucleation behavior.This study provides valuable insights into enhancing the surface pretreatment of niobium substrates during the growth of Nb_(3)Sn thin films using the vapor diffusion method.展开更多
Plant species diversity is one of the most widely used indicators in ecosystem management.The relation of species diversity with the size of the sample plot has not been fully determined for Oriental beech forests(Fag...Plant species diversity is one of the most widely used indicators in ecosystem management.The relation of species diversity with the size of the sample plot has not been fully determined for Oriental beech forests(Fagus orientalis Lipsky),a widespread species in the Hyrcanian region.Assessing the impacts of plot size on species diversity is fundamental for an ecosystem-based approach to forest management.This study determined the relation of species diversity and plot size by investigating species richness and abundance of both canopy and forest floor.Two hundred and fifty-six sample plots of 625 m^(2) each were layout in a grid pattern across 16 ha.Base plots(25 m×25 m)were integrated in different scales to investigate the effect of plot size on species diversity.The total included nine plots of 0.063,0.125,0.188,0.250,0.375,0.500,0.563,0.750 and 1 ha.Ten biodiversity indices were calculated.The results show that species richness in the different plot sizes was less than the actual value.The estimated value of the Simpson species diversity index was not significantly different from actual values for both canopy and forest floor diversity.The coefficient of variation of this index for the 1-ha sample plot showed the lowest amount across different plot sizes.Inverse Hill species diversity was insignificant difference across different plot sizes with an area greater than 0.500 ha.The modified Hill evenness index for the 1-ha sample size was a correct estimation of the 16-ha for both canopy and forest floor;however,the precision estimation was higher for the canopy layer.All plots greater than 0.250-ha provided an accurate estimation of the Camargo evenness index for forest floor species,but was inaccurate across different plot sizes for the canopy layer.The results indicate that the same plot size did not have the same effect across species diversity measurements.Our results show that correct estimation of species diversity measurements is related to the selection of appropriate indicators and plot size to increase the accuracy of the estimate so that the cost and time of biodiversity management may be reduced.展开更多
The characterization and clustering of rock discontinuity sets are a crucial and challenging task in rock mechanics and geotechnical engineering.Over the past few decades,the clustering of discontinuity sets has under...The characterization and clustering of rock discontinuity sets are a crucial and challenging task in rock mechanics and geotechnical engineering.Over the past few decades,the clustering of discontinuity sets has undergone rapid and remarkable development.However,there is no relevant literature summarizing these achievements,and this paper attempts to elaborate on the current status and prospects in this field.Specifically,this review aims to discuss the development process of clustering methods for discontinuity sets and the state-of-the-art relevant algorithms.First,we introduce the importance of discontinuity clustering analysis and follow the comprehensive characterization approaches of discontinuity data.A bibliometric analysis is subsequently conducted to clarify the current status and development characteristics of the clustering of discontinuity sets.The methods for the clustering analysis of rock discontinuities are reviewed in terms of single-and multi-parameter clustering methods.Single-parameter methods can be classified into empirical judgment methods,dynamic clustering methods,relative static clustering methods,and static clustering methods,reflecting the continuous optimization and improvement of clustering algorithms.Moreover,this paper compares the current mainstream of single-parameter clustering methods with multi-parameter clustering methods.It is emphasized that the current single-parameter clustering methods have reached their performance limits,with little room for improvement,and that there is a need to extend the study of multi-parameter clustering methods.Finally,several suggestions are offered for future research on the clustering of discontinuity sets.展开更多
In this paper,an image processing algorithm which is able to synthesize material textures of arbitrary shapes is proposed.The presented approach uses an arbitrary image to construct a structure layer of the material.T...In this paper,an image processing algorithm which is able to synthesize material textures of arbitrary shapes is proposed.The presented approach uses an arbitrary image to construct a structure layer of the material.The resulting structure layer is then used to constrain the material texture synthesis.The field of second-moment matrices is used to represent the structure layer.Many tests with various constraint images are conducted to ensure that the proposed approach accurately reproduces the visual aspects of the input material sample.The results demonstrate that the proposed algorithm is able to accurately synthesize arbitrary-shaped material textures while respecting the local characteristics of the exemplar.This paves the way toward the synthesis of 3D material textures of arbitrary shapes from 2D material samples,which has a wide application range in virtual material design and materials characterization.展开更多
Sb_(2)Se_(3)solar cells have achieved a power conversion efficiency(PCE)of over 10%.However,the serious open-circuit voltage deficit(VOC-deificit),induced by the hard-to-control crystal orientation and heterojunction ...Sb_(2)Se_(3)solar cells have achieved a power conversion efficiency(PCE)of over 10%.However,the serious open-circuit voltage deficit(VOC-deificit),induced by the hard-to-control crystal orientation and heterojunction interface reaction,limits the PCE of vapor transport deposition(VTD)processed Sb_(2)Se_(3)solar cells.To overcome the VOC-deficit problem of VTD processed Sb_(2)Se_(3)solar cells,herein,an in-situ bandgap regulation strategy is innovatively proposed to prepare a wide band gap Sb2(S,Se)3seed layer(WBSL)at CdS/Sb_(2)Se_(3)heterojunction interface to improve the PCE of Sb_(2)Se_(3)solar cells.The analysis results show that the introduced Sb2(S,Se)3seed layer can enhance the[001]orientation of Sb_(2)Se_(3)thin films,broaden the band gap of heterojunction interface,and realize a"Spike-like"conduction band alignment with ΔE_(c)=0.11 eV.In addition,thanks to the suppressed CdS/Sb_(2)Se_(3)interface reaction after WBSL application,the depletion region width of Sb_(2)Se_(3)solar cells is widened,and the quality of CdS/Sb_(2)Se_(3)interface and the carrier transporting performance of Sb_(2)Se_(3)solar cells are significantly improved as well.Moreover,the harmful Se vacancy defects near the front interface of Sb_(2)Se_(3)solar cells can be greatly diminished by WBSL.Finally,the PCE of Sb_(2)Se_(3)solar cells is improved from 7.0%to 7.6%;meanwhile the VOCis increased to 466 mV which is the highest value for the VTD derived Sb_(2)Se_(3)solar cells.This work will provide a valuable reference for the interface and orientation regulation of antimony-based chalcogenide solar cells.展开更多
The prediction of the fracture plane orientation in fatigue is a scientific topic and remains relevant for every type of material. However, in this work, we compared the orientation of the fracture plane obtained expe...The prediction of the fracture plane orientation in fatigue is a scientific topic and remains relevant for every type of material. However, in this work, we compared the orientation of the fracture plane obtained experimentally through tests on specimens under multiaxial loading with that calculated by the variance method. In the statistical approach criteria, several methods have been developed but we have presented only one method, namely the variance method using the equivalent stress. She assumes that the fracture plane orientation is the one on which the variance of the equivalent stress is maximum. Three types of equivalent stress are defined for this method [1]: normal stress, shear stress and combined normal and shear stress. The results obtained were compared with experimental results for multiaxial cyclic stress states, and it emerges that the variance method for the case of combined loading is conservative as it gives a better prediction of the fracture plane.展开更多
For thermal power enterprises,the traditional business model of scale expansion and a single product line restricts the development of electricity marketing.Therefore,to achieve the transformation and upgrading of the...For thermal power enterprises,the traditional business model of scale expansion and a single product line restricts the development of electricity marketing.Therefore,to achieve the transformation and upgrading of their electricity marketing,this study starts from the current situation of the electricity market and introduces in detail the market-oriented electricity marketing strategies of thermal power enterprises from four aspects:product strategy,price strategy,channel strategy,and promotion strategy.The analysis finds that a market-oriented electricity marketing strategy is not only an inevitable choice for thermal power enterprises to respond to current challenges but also an essential path for them to move toward high-quality development.Through continuous innovation and upgrading,thermal power enterprises will maintain a leading position in fierce market competition,achieve sustainable development,and make greater contributions to the prosperity and development of the energy industry.展开更多
Detecting oriented targets in remote sensing images amidst complex and heterogeneous backgrounds remains a formidable challenge in the field of object detection.Current frameworks for oriented detection modules are co...Detecting oriented targets in remote sensing images amidst complex and heterogeneous backgrounds remains a formidable challenge in the field of object detection.Current frameworks for oriented detection modules are constrained by intrinsic limitations,including excessive computational and memory overheads,discrepancies between predefined anchors and ground truth bounding boxes,intricate training processes,and feature alignment inconsistencies.To overcome these challenges,we present ASL-OOD(Angle-based SIOU Loss for Oriented Object Detection),a novel,efficient,and robust one-stage framework tailored for oriented object detection.The ASL-OOD framework comprises three core components:the Transformer-based Backbone(TB),the Transformer-based Neck(TN),and the Angle-SIOU(Scylla Intersection over Union)based Decoupled Head(ASDH).By leveraging the Swin Transformer,the TB and TN modules offer several key advantages,such as the capacity to model long-range dependencies,preserve high-resolution feature representations,seamlessly integrate multi-scale features,and enhance parameter efficiency.These improvements empower the model to accurately detect objects across varying scales.The ASDH module further enhances detection performance by incorporating angle-aware optimization based on SIOU,ensuring precise angular consistency and bounding box coherence.This approach effectively harmonizes shape loss and distance loss during the optimization process,thereby significantly boosting detection accuracy.Comprehensive evaluations and ablation studies on standard benchmark datasets such as DOTA with an mAP(mean Average Precision)of 80.16 percent,HRSC2016 with an mAP of 91.07 percent,MAR20 with an mAP of 85.45 percent,and UAVDT with an mAP of 39.7 percent demonstrate the clear superiority of ASL-OOD over state-of-the-art oriented object detection models.These findings underscore the model’s efficacy as an advanced solution for challenging remote sensing object detection tasks.展开更多
In recent years,service computing has been widely integrated into software development.Web service development,especially under the RESTful schema,needs to guide students in transferring from object-oriented to resour...In recent years,service computing has been widely integrated into software development.Web service development,especially under the RESTful schema,needs to guide students in transferring from object-oriented to resource-oriented architectural thinking and cultivating students’literacy in design thinking,design patterns,and development methods.This paper introduces the foundations of service thinking with a brief review of service sciences,the core features of service thinking,and how to train service thinking of students.It also introduces a case study in Shandong University in the construction of a service computing curriculum system,especially how to highlight the cultivation of service thinking in the design of service software system.展开更多
Fracture(fault)reactivation can lead to dynamic geological hazards including earthquakes,rock collapses,landslides,and rock bursts.True triaxial compression tests were conducted to analyze the fracture reactivation pr...Fracture(fault)reactivation can lead to dynamic geological hazards including earthquakes,rock collapses,landslides,and rock bursts.True triaxial compression tests were conducted to analyze the fracture reactivation process under two different orientations of σ_(2),i.e.σ_(2) parallel to the fracture plane(Scheme 2)and σ_(2) cutting through the fracture plane(Scheme 3),under varying σ_(3) from 10 MPa to 40 MPa.The peak or fracture reactivation strength,deformation,failure mode,and post-peak mechanical behavior of intact(Scheme 1)and pre-fractured(Schemes 2 and 3)specimens were also compared.Results show that for intact specimens,the stress remains nearly constant in the residual sliding stage with no stick-slip,and the newly formed fracture surface only propagates along the σ_(2) direction when σ_(3) ranges from 10 MPa to 30 MPa,while it extends along both σ_(2) and σ_(3) directions when σ_(3) increases to 40 MPa;for the pre-fractured specimens,the fractures are usually reactivated under all the σ_(3) levels in Scheme 2,but fracture reactivation only occurs when σ_(3) is greater than 25 MPa in Scheme 3,below which new faulting traversing the original macro fracture occurs.In all the test schemes,both ε_(2) and ε_(3) experience an accumulative process of elongation,after which an abrupt change occurs at the point of the final failure;the degree of this change is dependent on the orientation of the new faulting or the slip direction of the original fracture,and it is generally more than 10 times larger in the slip direction of the original fracture than in the non-slip direction.Besides,the differential stress(peak stress)required for reactivation and the post-peak stress drop increase with increasing σ_(3).Post-peak stress drop and residual strength in Scheme 3 are generally greater than those in Scheme 2 at the same σ_(3) value.Our study clearly shows that intermediate principal stress orientation not only affects the fracture reactivation strength but also influences the slip deformation and failure modes.These new findings facilitate the mitigation of dynamic geological hazards associated with fracture and fault slip.展开更多
Rock discontinuities control rock mechanical behaviors and significantly influence the stability of rock masses.However,existing discontinuity mapping algorithms are susceptible to noise,and the calculation results ca...Rock discontinuities control rock mechanical behaviors and significantly influence the stability of rock masses.However,existing discontinuity mapping algorithms are susceptible to noise,and the calculation results cannot be fed back to users timely.To address this issue,we proposed a human-machine interaction(HMI)method for discontinuity mapping.Users can help the algorithm identify the noise and make real-time result judgments and parameter adjustments.For this,a regular cube was selected to illustrate the workflows:(1)point cloud was acquired using remote sensing;(2)the HMI method was employed to select reference points and angle thresholds to detect group discontinuity;(3)individual discontinuities were extracted from the group discontinuity using a density-based cluster algorithm;and(4)the orientation of each discontinuity was measured based on a plane fitting algorithm.The method was applied to a well-studied highway road cut and a complex natural slope.The consistency of the computational results with field measurements demonstrates its good accuracy,and the average error in the dip direction and dip angle for both cases was less than 3.Finally,the computational time of the proposed method was compared with two other popular algorithms,and the reduction in computational time by tens of times proves its high computational efficiency.This method provides geologists and geological engineers with a new idea to map rapidly and accurately rock structures under large amounts of noises or unclear features.展开更多
Ground penetrating radar(GPR),as a fast,efficient,and non-destructive detection device,holds great potential for the detection of shallow subsurface environments,such as urban road subsurface monitoring.However,the in...Ground penetrating radar(GPR),as a fast,efficient,and non-destructive detection device,holds great potential for the detection of shallow subsurface environments,such as urban road subsurface monitoring.However,the interpretation of GPR echo images often relies on manual recognition by experienced engineers.In order to address the automatic interpretation of cavity targets in GPR echo images,a recognition-algorithm based on Gaussian mixed model-hidden Markov model(GMM-HMM)is proposed,which can recognize three dimensional(3D)underground voids automatically.First,energy detection on the echo images is performed,whereby the data is preprocessed and pre-filtered.Then,edge histogram descriptor(EHD),histogram of oriented gradient(HOG),and Log-Gabor filters are used to extract features from the images.The traditional method can only be applied to 2D images and pre-processing is required for C-scan images.Finally,the aggregated features are fed into the GMM-HMM for classification and compared with two other methods,long short-term memory(LSTM)and gate recurrent unit(GRU).By testing on a simulated dataset,an accuracy rate of 90%is obtained,demonstrating the effectiveness and efficiency of our proposed method.展开更多
The term hepatolithiasis describes the presence of biliary stones within the intrahepatic bile ducts,above the hilar confluence of the hepatic ducts.The disease is more prevalent in Asia,mainly owing to socioeconomic ...The term hepatolithiasis describes the presence of biliary stones within the intrahepatic bile ducts,above the hilar confluence of the hepatic ducts.The disease is more prevalent in Asia,mainly owing to socioeconomic and dietary factors,as well as the prevalence of biliary parasites.In the last century,owing to migration,its global incidence has increased.The main pathophysiological mechanisms involve cholangitis,bile infection and biliary strictures,creating a self-sustaining cycle that perpetuates the disease,frequently characterised by recurrent episodes of bacterial infection referred to as syndrome of“recurrent pyogenic cholangitis”.Furthermore,long-standing hepatolithiasis is a known risk factor for development of intrahepatic cholangiocarcinoma.Various classifications have aimed at providing useful insight of clinically relevant aspects and guidance for treatment.The management of symptomatic patients and those with complications can be complex,and relies upon a multidisciplinary team of hepatologists,endoscopists,interventional radiologists and hepatobiliary surgeons,with the main goal being to offer relief from the clinical presentations and prevent the development of more serious complications.This comprehensive review provides insight on various aspects of hepatolithiasis,with a focus on epidemiology,new evidence on pathophysiology,most important clinical aspects,different classification systems and contemporary management.展开更多
The integrated repair of bone and cartilage boasts advantages for osteochondral restoration such as a long-term repair effect and less deterioration compared to repairing cartilage alone.Constructing multifactorial,sp...The integrated repair of bone and cartilage boasts advantages for osteochondral restoration such as a long-term repair effect and less deterioration compared to repairing cartilage alone.Constructing multifactorial,spatially oriented scaffolds to stimulate osteochondral regeneration,has immense significance.Herein,targeted drugs,namely kartogenin@polydopamine(KGN@PDA)nanoparticles for cartilage repair and miRNA@calcium phosphate(miRNA@CaP)NPs for bone regeneration,were in situ deposited on a patterned supramolecular-assembled 2-ureido-4[lH]-pyrimidinone(UPy)modified gelation hydrogel film,facilitated by the dynamic and responsive coordination and complexation of metal ions and their ligands.This hydrogel film can be rolled into a cylindrical plug,mimicking the Haversian canal structure of natural bone.The resultant hydrogel demonstrates stable mechanical properties,a self-healing ability,a high capability for reactive oxygen species capture,and controlled release of KGN and miR-26a.In vitro,KGN@PDA and miRNA@CaP promote chondrogenic and osteogenic differentiation of mesenchymal stem cells via the JNK/RUNX1 and GSK-3β/β-catenin pathways,respectively.In vivo,the osteochondral plug exhibits optimal subchondral bone and cartilage regeneration,evidenced by a significant increase in glycosaminoglycan and collagen accumulation in specific zones,along with the successful integration of neocartilage with subchondral bone.This biomaterial delivery approach represents a significant toward improved osteochondral repair.展开更多
To achieve the loading of the stress path of hard rock,the spherical discrete element model(DEM)and the new flexible membrane technology were utilized to realize the transient loading of three principal stresses with ...To achieve the loading of the stress path of hard rock,the spherical discrete element model(DEM)and the new flexible membrane technology were utilized to realize the transient loading of three principal stresses with arbitrary magnitudes and orientations.Furthermore,based on the deep tunnel of China Jinping Underground Laboratory II(CJPL-II),the deformation and fracture evolution characteristics of deep hard rock induced by excavation stress path were analyzed,and the mechanisms of transient loading-unloading and stress rotation-induced fractures were revealed from a mesoscopic perspective.The results indicated that the stressestrain curve exhibits different trends and degrees of sudden changes when subjected to transient changes in principal stress,accompanied by sudden changes in strain rate.Stress rotation induces spatially directional deformation,resulting in fractures of different degrees and orientations,and increasing the degree of deformation anisotropy.The correlation between the degree of induced fracture and the unloading magnitude of minimum principal stress,as well as its initial level is significant and positive.The process of mechanical response during transient unloading exhibits clear nonlinearity and directivity.After transient unloading,both the minimum principal stress and minimum principal strain rate decrease sharply and then tend to stabilize.This occurs from the edge to the interior and from the direction of the minimum principal stress to the direction of the maximum principal stress on theε1-ε3 plane.Transient unloading will induce a tensile stress wave.The ability to induce fractures due to changes in principal stress magnitude,orientation and rotation paths gradually increases.The analysis indicates a positive correlation between the abrupt change amplitude of strain rate and the maximum unloading magnitude,which is determined by the magnitude and rotation of principal stress.A high tensile strain rate is more likely to induce fractures under low minimum principal stress.展开更多
文摘Grain-oriented silicon steels were prepared at different heating rates during high temperature annealing,in which the evolution of magnetic properties,grain orientations and precipitates were studied.To illustrate the Zener factor,the diameter and number density of precipitates of interrupted testing samples were statistically calculated.The effect of precipitate ripening on the Goss texture and magnetic property was investigated.Data indicated that the trend of Zener factor was similar under different heating rates,first increasing and then decreasing,and that the precipitate maturing was greatly inhibited as the heating rate increased.Secondary recrystallization was developed at the temperature of 1010℃when a heating rate of 5℃/h was used,resulting in Goss,Brass and{110}<227>oriented grains growing abnormally and a magnetic induction intensity of 1.90T.Furthermore,increasing the heating rate to 20℃/h would inhibit the development of undesirable oriented grains and obtain a sharp Goss texture.However,when the heating rate was extremely fast,such as 40℃/h,poor secondary recrystallization was developed with many island grains,corresponding to a decrease in magnetic induction intensity to 1.87 T.At a suitable heating rate of 20℃/h,the sharpest Goss texture and the highest magnetic induction of 1.94 T with an onset secondary recrystallization temperature of 1020℃were found among the experimental variables in this study.The heating rate affected the initial temperature of secondary recrystallization by controlling the maturation of precipitates,leading to the deviation and dispersion of Goss texture,thereby reducing the magnetic properties.
基金supported by the National Natural Science Foundation of China(32370484)China Scholarship Council,National Science&Technology Fundamental Resources Investigation Program of China(2019FY101800)the National Animal Collection Resource Center,China.
文摘We review the genus Paraglenurus van der Weele,1909 in China,and provide a new Chinese record:P.scopifer(Gerstaeker,1888)from Orchid Island(Lanyu).Additionally,we describe a new species of Paraglenurus from South Vietnam,i.e.,P.badanoi sp.nov.,which represents the first record of this genus in Indochina.Furthermore,we confirm that the paratypes of P.pumilus(Yang,1997)are actually a distinct new species in the genus Indophanes Banks,1940,i.e.,I.zhiliangi sp.nov.
基金supported by the National Natural Science Foundation of China(No.12175283)Youth Innovation Promotion Association of Chinese Academy of Sciences(2020410)Advanced Energy Science and Technology Guangdong Laboratory(HND20TDSPCD,HND22PTDZD).
文摘Growth of high-quality Nb_(3)Sn thin films for superconducting radiofrequency(SRF)applications using the vapor diffusion method requires a uniform distribution of tin nuclei on the niobium(Nb)surface.This study examines the mechanism underlying the observed non-uniform distribution of tin nuclei with tin chloride SnCl_(2).Electron backscatter diffraction(EBSD)analysis was used to examine the correlation between the nucleation behavior and orientation of niobium grains in the substrate.The findings of the density functional theory(DFT)simulation are in good agreement with the experimental results,showing that the non-uniform distribution of tin nuclei is the result of the adsorption energy of SnCl_(2)molecules by varied niobium grain orientations.Further analysis indicated that the surface roughness and grain size of niobium also played significant roles in the nucleation behavior.This study provides valuable insights into enhancing the surface pretreatment of niobium substrates during the growth of Nb_(3)Sn thin films using the vapor diffusion method.
基金funded by Gorgan University of Agricultural Sciences and Natural Resources(grant number 9318124503).
文摘Plant species diversity is one of the most widely used indicators in ecosystem management.The relation of species diversity with the size of the sample plot has not been fully determined for Oriental beech forests(Fagus orientalis Lipsky),a widespread species in the Hyrcanian region.Assessing the impacts of plot size on species diversity is fundamental for an ecosystem-based approach to forest management.This study determined the relation of species diversity and plot size by investigating species richness and abundance of both canopy and forest floor.Two hundred and fifty-six sample plots of 625 m^(2) each were layout in a grid pattern across 16 ha.Base plots(25 m×25 m)were integrated in different scales to investigate the effect of plot size on species diversity.The total included nine plots of 0.063,0.125,0.188,0.250,0.375,0.500,0.563,0.750 and 1 ha.Ten biodiversity indices were calculated.The results show that species richness in the different plot sizes was less than the actual value.The estimated value of the Simpson species diversity index was not significantly different from actual values for both canopy and forest floor diversity.The coefficient of variation of this index for the 1-ha sample plot showed the lowest amount across different plot sizes.Inverse Hill species diversity was insignificant difference across different plot sizes with an area greater than 0.500 ha.The modified Hill evenness index for the 1-ha sample size was a correct estimation of the 16-ha for both canopy and forest floor;however,the precision estimation was higher for the canopy layer.All plots greater than 0.250-ha provided an accurate estimation of the Camargo evenness index for forest floor species,but was inaccurate across different plot sizes for the canopy layer.The results indicate that the same plot size did not have the same effect across species diversity measurements.Our results show that correct estimation of species diversity measurements is related to the selection of appropriate indicators and plot size to increase the accuracy of the estimate so that the cost and time of biodiversity management may be reduced.
基金funding support from the National Natural Science Foundation of China(Grant No.42007269)the Young Talent Fund of Xi'an Association for Science and Technology(Grant No.959202313094)the Fundamental Research Funds for the Central Universities,CHD(Grant No.300102263401).
文摘The characterization and clustering of rock discontinuity sets are a crucial and challenging task in rock mechanics and geotechnical engineering.Over the past few decades,the clustering of discontinuity sets has undergone rapid and remarkable development.However,there is no relevant literature summarizing these achievements,and this paper attempts to elaborate on the current status and prospects in this field.Specifically,this review aims to discuss the development process of clustering methods for discontinuity sets and the state-of-the-art relevant algorithms.First,we introduce the importance of discontinuity clustering analysis and follow the comprehensive characterization approaches of discontinuity data.A bibliometric analysis is subsequently conducted to clarify the current status and development characteristics of the clustering of discontinuity sets.The methods for the clustering analysis of rock discontinuities are reviewed in terms of single-and multi-parameter clustering methods.Single-parameter methods can be classified into empirical judgment methods,dynamic clustering methods,relative static clustering methods,and static clustering methods,reflecting the continuous optimization and improvement of clustering algorithms.Moreover,this paper compares the current mainstream of single-parameter clustering methods with multi-parameter clustering methods.It is emphasized that the current single-parameter clustering methods have reached their performance limits,with little room for improvement,and that there is a need to extend the study of multi-parameter clustering methods.Finally,several suggestions are offered for future research on the clustering of discontinuity sets.
文摘In this paper,an image processing algorithm which is able to synthesize material textures of arbitrary shapes is proposed.The presented approach uses an arbitrary image to construct a structure layer of the material.The resulting structure layer is then used to constrain the material texture synthesis.The field of second-moment matrices is used to represent the structure layer.Many tests with various constraint images are conducted to ensure that the proposed approach accurately reproduces the visual aspects of the input material sample.The results demonstrate that the proposed algorithm is able to accurately synthesize arbitrary-shaped material textures while respecting the local characteristics of the exemplar.This paves the way toward the synthesis of 3D material textures of arbitrary shapes from 2D material samples,which has a wide application range in virtual material design and materials characterization.
基金supported by the National Natural Science Foundation of China(62305064)the Research Start-up Fund for Young Teachers of Fuzhou University(602592)+1 种基金the Young and Middleaged Teacher Education Research Project of Fujian Province(JAT220011)the Fujian Science&Technology Innovation Laboratory Optoelectronic Information of China(Grant No.2021ZZ124).
文摘Sb_(2)Se_(3)solar cells have achieved a power conversion efficiency(PCE)of over 10%.However,the serious open-circuit voltage deficit(VOC-deificit),induced by the hard-to-control crystal orientation and heterojunction interface reaction,limits the PCE of vapor transport deposition(VTD)processed Sb_(2)Se_(3)solar cells.To overcome the VOC-deficit problem of VTD processed Sb_(2)Se_(3)solar cells,herein,an in-situ bandgap regulation strategy is innovatively proposed to prepare a wide band gap Sb2(S,Se)3seed layer(WBSL)at CdS/Sb_(2)Se_(3)heterojunction interface to improve the PCE of Sb_(2)Se_(3)solar cells.The analysis results show that the introduced Sb2(S,Se)3seed layer can enhance the[001]orientation of Sb_(2)Se_(3)thin films,broaden the band gap of heterojunction interface,and realize a"Spike-like"conduction band alignment with ΔE_(c)=0.11 eV.In addition,thanks to the suppressed CdS/Sb_(2)Se_(3)interface reaction after WBSL application,the depletion region width of Sb_(2)Se_(3)solar cells is widened,and the quality of CdS/Sb_(2)Se_(3)interface and the carrier transporting performance of Sb_(2)Se_(3)solar cells are significantly improved as well.Moreover,the harmful Se vacancy defects near the front interface of Sb_(2)Se_(3)solar cells can be greatly diminished by WBSL.Finally,the PCE of Sb_(2)Se_(3)solar cells is improved from 7.0%to 7.6%;meanwhile the VOCis increased to 466 mV which is the highest value for the VTD derived Sb_(2)Se_(3)solar cells.This work will provide a valuable reference for the interface and orientation regulation of antimony-based chalcogenide solar cells.
文摘The prediction of the fracture plane orientation in fatigue is a scientific topic and remains relevant for every type of material. However, in this work, we compared the orientation of the fracture plane obtained experimentally through tests on specimens under multiaxial loading with that calculated by the variance method. In the statistical approach criteria, several methods have been developed but we have presented only one method, namely the variance method using the equivalent stress. She assumes that the fracture plane orientation is the one on which the variance of the equivalent stress is maximum. Three types of equivalent stress are defined for this method [1]: normal stress, shear stress and combined normal and shear stress. The results obtained were compared with experimental results for multiaxial cyclic stress states, and it emerges that the variance method for the case of combined loading is conservative as it gives a better prediction of the fracture plane.
文摘For thermal power enterprises,the traditional business model of scale expansion and a single product line restricts the development of electricity marketing.Therefore,to achieve the transformation and upgrading of their electricity marketing,this study starts from the current situation of the electricity market and introduces in detail the market-oriented electricity marketing strategies of thermal power enterprises from four aspects:product strategy,price strategy,channel strategy,and promotion strategy.The analysis finds that a market-oriented electricity marketing strategy is not only an inevitable choice for thermal power enterprises to respond to current challenges but also an essential path for them to move toward high-quality development.Through continuous innovation and upgrading,thermal power enterprises will maintain a leading position in fierce market competition,achieve sustainable development,and make greater contributions to the prosperity and development of the energy industry.
基金supported by the Key Research and Development Program of Shaanxi Province(2024GX-YBXM-010).
文摘Detecting oriented targets in remote sensing images amidst complex and heterogeneous backgrounds remains a formidable challenge in the field of object detection.Current frameworks for oriented detection modules are constrained by intrinsic limitations,including excessive computational and memory overheads,discrepancies between predefined anchors and ground truth bounding boxes,intricate training processes,and feature alignment inconsistencies.To overcome these challenges,we present ASL-OOD(Angle-based SIOU Loss for Oriented Object Detection),a novel,efficient,and robust one-stage framework tailored for oriented object detection.The ASL-OOD framework comprises three core components:the Transformer-based Backbone(TB),the Transformer-based Neck(TN),and the Angle-SIOU(Scylla Intersection over Union)based Decoupled Head(ASDH).By leveraging the Swin Transformer,the TB and TN modules offer several key advantages,such as the capacity to model long-range dependencies,preserve high-resolution feature representations,seamlessly integrate multi-scale features,and enhance parameter efficiency.These improvements empower the model to accurately detect objects across varying scales.The ASDH module further enhances detection performance by incorporating angle-aware optimization based on SIOU,ensuring precise angular consistency and bounding box coherence.This approach effectively harmonizes shape loss and distance loss during the optimization process,thereby significantly boosting detection accuracy.Comprehensive evaluations and ablation studies on standard benchmark datasets such as DOTA with an mAP(mean Average Precision)of 80.16 percent,HRSC2016 with an mAP of 91.07 percent,MAR20 with an mAP of 85.45 percent,and UAVDT with an mAP of 39.7 percent demonstrate the clear superiority of ASL-OOD over state-of-the-art oriented object detection models.These findings underscore the model’s efficacy as an advanced solution for challenging remote sensing object detection tasks.
基金the support provided by the“New 20 Regulations for Universities”funding program of Jinan(202228089)the TaiS han Industrial Experts Programme(tscx202312128)。
文摘In recent years,service computing has been widely integrated into software development.Web service development,especially under the RESTful schema,needs to guide students in transferring from object-oriented to resource-oriented architectural thinking and cultivating students’literacy in design thinking,design patterns,and development methods.This paper introduces the foundations of service thinking with a brief review of service sciences,the core features of service thinking,and how to train service thinking of students.It also introduces a case study in Shandong University in the construction of a service computing curriculum system,especially how to highlight the cultivation of service thinking in the design of service software system.
基金funding support from the National Nature Science Foundation of China(Grant No.42272334)the National Key Research and Development Program of China(Grant No.2022YFE0137200)the Taishan Scholars Program(Grant No.2019RKB01083).
文摘Fracture(fault)reactivation can lead to dynamic geological hazards including earthquakes,rock collapses,landslides,and rock bursts.True triaxial compression tests were conducted to analyze the fracture reactivation process under two different orientations of σ_(2),i.e.σ_(2) parallel to the fracture plane(Scheme 2)and σ_(2) cutting through the fracture plane(Scheme 3),under varying σ_(3) from 10 MPa to 40 MPa.The peak or fracture reactivation strength,deformation,failure mode,and post-peak mechanical behavior of intact(Scheme 1)and pre-fractured(Schemes 2 and 3)specimens were also compared.Results show that for intact specimens,the stress remains nearly constant in the residual sliding stage with no stick-slip,and the newly formed fracture surface only propagates along the σ_(2) direction when σ_(3) ranges from 10 MPa to 30 MPa,while it extends along both σ_(2) and σ_(3) directions when σ_(3) increases to 40 MPa;for the pre-fractured specimens,the fractures are usually reactivated under all the σ_(3) levels in Scheme 2,but fracture reactivation only occurs when σ_(3) is greater than 25 MPa in Scheme 3,below which new faulting traversing the original macro fracture occurs.In all the test schemes,both ε_(2) and ε_(3) experience an accumulative process of elongation,after which an abrupt change occurs at the point of the final failure;the degree of this change is dependent on the orientation of the new faulting or the slip direction of the original fracture,and it is generally more than 10 times larger in the slip direction of the original fracture than in the non-slip direction.Besides,the differential stress(peak stress)required for reactivation and the post-peak stress drop increase with increasing σ_(3).Post-peak stress drop and residual strength in Scheme 3 are generally greater than those in Scheme 2 at the same σ_(3) value.Our study clearly shows that intermediate principal stress orientation not only affects the fracture reactivation strength but also influences the slip deformation and failure modes.These new findings facilitate the mitigation of dynamic geological hazards associated with fracture and fault slip.
基金supported by the National Key R&D Program of China(No.2023YFC3081200)the National Natural Science Foundation of China(No.42077264)the Scientific Research Project of PowerChina Huadong Engineering Corporation Limited(HDEC-2022-0301).
文摘Rock discontinuities control rock mechanical behaviors and significantly influence the stability of rock masses.However,existing discontinuity mapping algorithms are susceptible to noise,and the calculation results cannot be fed back to users timely.To address this issue,we proposed a human-machine interaction(HMI)method for discontinuity mapping.Users can help the algorithm identify the noise and make real-time result judgments and parameter adjustments.For this,a regular cube was selected to illustrate the workflows:(1)point cloud was acquired using remote sensing;(2)the HMI method was employed to select reference points and angle thresholds to detect group discontinuity;(3)individual discontinuities were extracted from the group discontinuity using a density-based cluster algorithm;and(4)the orientation of each discontinuity was measured based on a plane fitting algorithm.The method was applied to a well-studied highway road cut and a complex natural slope.The consistency of the computational results with field measurements demonstrates its good accuracy,and the average error in the dip direction and dip angle for both cases was less than 3.Finally,the computational time of the proposed method was compared with two other popular algorithms,and the reduction in computational time by tens of times proves its high computational efficiency.This method provides geologists and geological engineers with a new idea to map rapidly and accurately rock structures under large amounts of noises or unclear features.
基金National Natural Science Foundation of China(62071147)。
文摘Ground penetrating radar(GPR),as a fast,efficient,and non-destructive detection device,holds great potential for the detection of shallow subsurface environments,such as urban road subsurface monitoring.However,the interpretation of GPR echo images often relies on manual recognition by experienced engineers.In order to address the automatic interpretation of cavity targets in GPR echo images,a recognition-algorithm based on Gaussian mixed model-hidden Markov model(GMM-HMM)is proposed,which can recognize three dimensional(3D)underground voids automatically.First,energy detection on the echo images is performed,whereby the data is preprocessed and pre-filtered.Then,edge histogram descriptor(EHD),histogram of oriented gradient(HOG),and Log-Gabor filters are used to extract features from the images.The traditional method can only be applied to 2D images and pre-processing is required for C-scan images.Finally,the aggregated features are fed into the GMM-HMM for classification and compared with two other methods,long short-term memory(LSTM)and gate recurrent unit(GRU).By testing on a simulated dataset,an accuracy rate of 90%is obtained,demonstrating the effectiveness and efficiency of our proposed method.
文摘The term hepatolithiasis describes the presence of biliary stones within the intrahepatic bile ducts,above the hilar confluence of the hepatic ducts.The disease is more prevalent in Asia,mainly owing to socioeconomic and dietary factors,as well as the prevalence of biliary parasites.In the last century,owing to migration,its global incidence has increased.The main pathophysiological mechanisms involve cholangitis,bile infection and biliary strictures,creating a self-sustaining cycle that perpetuates the disease,frequently characterised by recurrent episodes of bacterial infection referred to as syndrome of“recurrent pyogenic cholangitis”.Furthermore,long-standing hepatolithiasis is a known risk factor for development of intrahepatic cholangiocarcinoma.Various classifications have aimed at providing useful insight of clinically relevant aspects and guidance for treatment.The management of symptomatic patients and those with complications can be complex,and relies upon a multidisciplinary team of hepatologists,endoscopists,interventional radiologists and hepatobiliary surgeons,with the main goal being to offer relief from the clinical presentations and prevent the development of more serious complications.This comprehensive review provides insight on various aspects of hepatolithiasis,with a focus on epidemiology,new evidence on pathophysiology,most important clinical aspects,different classification systems and contemporary management.
基金the Natural Science Foundation of China(Grant Nos.82072413,82101649)National Key Research and Development Program of China(Grant Nos.2021YFE0105400).
文摘The integrated repair of bone and cartilage boasts advantages for osteochondral restoration such as a long-term repair effect and less deterioration compared to repairing cartilage alone.Constructing multifactorial,spatially oriented scaffolds to stimulate osteochondral regeneration,has immense significance.Herein,targeted drugs,namely kartogenin@polydopamine(KGN@PDA)nanoparticles for cartilage repair and miRNA@calcium phosphate(miRNA@CaP)NPs for bone regeneration,were in situ deposited on a patterned supramolecular-assembled 2-ureido-4[lH]-pyrimidinone(UPy)modified gelation hydrogel film,facilitated by the dynamic and responsive coordination and complexation of metal ions and their ligands.This hydrogel film can be rolled into a cylindrical plug,mimicking the Haversian canal structure of natural bone.The resultant hydrogel demonstrates stable mechanical properties,a self-healing ability,a high capability for reactive oxygen species capture,and controlled release of KGN and miR-26a.In vitro,KGN@PDA and miRNA@CaP promote chondrogenic and osteogenic differentiation of mesenchymal stem cells via the JNK/RUNX1 and GSK-3β/β-catenin pathways,respectively.In vivo,the osteochondral plug exhibits optimal subchondral bone and cartilage regeneration,evidenced by a significant increase in glycosaminoglycan and collagen accumulation in specific zones,along with the successful integration of neocartilage with subchondral bone.This biomaterial delivery approach represents a significant toward improved osteochondral repair.
基金the financial support from the National Natural Science Foundation of China(Grant No.51839003)Liaoning Revitalization Talents Program(Grant No.XLYCYSZX 1902)Hubei Key Laboratory for Efficient Utilization and Agglomeration of Metallurgic Mineral Resources(Grant No.2023zy002).
文摘To achieve the loading of the stress path of hard rock,the spherical discrete element model(DEM)and the new flexible membrane technology were utilized to realize the transient loading of three principal stresses with arbitrary magnitudes and orientations.Furthermore,based on the deep tunnel of China Jinping Underground Laboratory II(CJPL-II),the deformation and fracture evolution characteristics of deep hard rock induced by excavation stress path were analyzed,and the mechanisms of transient loading-unloading and stress rotation-induced fractures were revealed from a mesoscopic perspective.The results indicated that the stressestrain curve exhibits different trends and degrees of sudden changes when subjected to transient changes in principal stress,accompanied by sudden changes in strain rate.Stress rotation induces spatially directional deformation,resulting in fractures of different degrees and orientations,and increasing the degree of deformation anisotropy.The correlation between the degree of induced fracture and the unloading magnitude of minimum principal stress,as well as its initial level is significant and positive.The process of mechanical response during transient unloading exhibits clear nonlinearity and directivity.After transient unloading,both the minimum principal stress and minimum principal strain rate decrease sharply and then tend to stabilize.This occurs from the edge to the interior and from the direction of the minimum principal stress to the direction of the maximum principal stress on theε1-ε3 plane.Transient unloading will induce a tensile stress wave.The ability to induce fractures due to changes in principal stress magnitude,orientation and rotation paths gradually increases.The analysis indicates a positive correlation between the abrupt change amplitude of strain rate and the maximum unloading magnitude,which is determined by the magnitude and rotation of principal stress.A high tensile strain rate is more likely to induce fractures under low minimum principal stress.
