Tax risk behavior causes serious loss of fiscal revenue,damages the country’s public infrastructure,and disturbs the market economic order of fair competition.In recent years,tax risk detection,driven by information ...Tax risk behavior causes serious loss of fiscal revenue,damages the country’s public infrastructure,and disturbs the market economic order of fair competition.In recent years,tax risk detection,driven by information technology such as data mining and artificial intelligence,has received extensive attention.To promote the high-quality development of tax risk detection methods,this paper provides the first comprehensive overview and summary of existing tax risk detection methods worldwide.More specifi-cally,it first discusses the causes and negative impacts of tax risk behaviors,along with the development of tax risk detection.It then focuses on data-mining-based tax risk detection methods utilized around the world.Based on the different principles employed by the algorithms,existing risk detection methods can be divided into two categories:relationship-based and non-relationship-based.A total of 14 risk detection methods are identified,and each method is thoroughly explored and analyzed.Finally,four major technical bottlenecks of current data-driven tax risk detection methods are analyzed and discussed,including the difficulty of integrating and using fiscal and tax fragmented knowledge,unexplainable risk detection results,the high cost of risk detection algorithms,and the reliance of existing algorithms on labeled information.After investigating these issues,it is concluded that knowledge-guided and datadriven big data knowledge engineering will be the development trend in the field of tax risk in the future;that is,the gradual transition of tax risk detection from informatization to intelligence is the future development direction.展开更多
Scanning electron microscopy(SEM)is a crucial tool in the field of materials science,providing valuable insightsinto the microstructural characteristics of materials.Unfortunately,SEM images often suffer from blurrine...Scanning electron microscopy(SEM)is a crucial tool in the field of materials science,providing valuable insightsinto the microstructural characteristics of materials.Unfortunately,SEM images often suffer from blurrinesscaused by improper hardware calibration or imaging automation errors,which present challenges in analyzingand interpretingmaterial characteristics.Consequently,rectifying the blurring of these images assumes paramountsignificance to enable subsequent analysis.To address this issue,we introduce a Material Images DeblurringNetwork(MIDNet)built upon the foundation of the Nonlinear Activation Free Network(NAFNet).MIDNetis meticulously tailored to address the blurring in images capturing the microstructure of materials.The keycontributions include enhancing the NAFNet architecture for better feature extraction and representation,integratinga novel soft attention mechanism to uncover important correlations between encoder and decoder,andintroducing newmulti-loss functions to improve training effectiveness and overallmodel performance.We conducta comprehensive set of experiments utilizing the material blurry dataset and compare them to several state-of-theartdeblurring methods.The experimental results demonstrate the applicability and effectiveness of MIDNet in thedomain of deblurring material microstructure images,with a PSNR(Peak Signal-to-Noise Ratio)reaching 35.26 dBand an SSIM(Structural Similarity)of 0.946.Our dataset is available at:https://github.com/woshigui/MIDNet.展开更多
The Cs_(2)NaInCl_(6) double perovskite is one of the most promising lead-free perovskites due to its exceptional stability and straightforward synthesis.However,it faces challenges related to inefficient photoluminesc...The Cs_(2)NaInCl_(6) double perovskite is one of the most promising lead-free perovskites due to its exceptional stability and straightforward synthesis.However,it faces challenges related to inefficient photoluminescence.Doping and high pressure are employed to tailor the optical properties of Cs_(2)NaInCl_(6).Herein,Sb^(3+)doped Cs_(2)NaInCl_(6)(Sb^(3+):Cs_(2)NaInCl_(6)) was synthesized and it exhibits blue emission with a photoluminescence quantum yield of up to 37.3%.Further,by employing pressure tuning,a blue stable emission under a very wide range from 2.7 GPa to 9.8 GPa is realized in Sb^(3+):Cs_(2)NaInCl_(6).Subsequently,the emission intensity of Sb^(3+):Cs_(2)NaInCl_(6) experiences a significant increase(3.3 times)at 19.0 GPa.It is revealed that the pressure-induced distinct emissions can be attributed to the carrier self-trapping and detrapping between Cs_(2)NaInCl_(6) and Sb^(3+).Notably,the lattice compression in the cubic phase inevitably modifies the band gap of Sb^(3+):Cs_(2)NaInCl_(6).Our findings provide valuable insights into effects of the high pressure in further boosting unique emission characteristics but also offer promising opportunities for development of doped double perovskites with enhanced optical functionalities.展开更多
In this study,the role of twin-twin interactions on the distributions of local defects(e.g.,dislocations)and stress fields in a magnesium alloy is investigated.A co-zone(1012)-(1012)tensile twin junction in a deformed...In this study,the role of twin-twin interactions on the distributions of local defects(e.g.,dislocations)and stress fields in a magnesium alloy is investigated.A co-zone(1012)-(1012)tensile twin junction in a deformed Mg-3wt.%Y alloy is analyzed using transmission electron microscopy(TEM).The results show that the morphology of the impinging(1012)twin is asymmetric,and the non-interacting boundary of the recipient(1012)twin is irregular.Detailed analysis of TEM images reveals that type-II pyramidal[1213](1212)dislocations concentrate in the vicinity of the twin-twin junction site.The same<c+a>dislocations are also observed inside the interacting twin domains along with a few <a> dislocations.The<c+a>dislocations emanating from the impinging(1012)twin boundary have edge character and are extended with faults parallel to the basal plane.In contrast,the<c+a>dislocations connected to the recipient(1012)twin are predominantly screw orientation and compact.Elasto-viscoplastic fast Fourier transform based crystal plasticity calculations are performed to rationalize the observed twin morphology and local dislocation distribution.The model calculations suggest that the local stress fields generated at the junction site where the two twins meet are responsible for the experimentally observed concentration of<c+a>dislocations.The calculated stress fields are asymmetric with respect to the junction site,explaining the observed asymmetric morphology of the impinging twin.Overall,these findings show strong effects of twin-twin interactions on the distribution of dislocations as well as the evolution of the twinned microstructure and as such,can help advance understanding of twinning in Mg alloys and their effect on mechanical behavior.展开更多
Osteoporosis as a systemic chronic skeletal disease is characterized by low bone mineral density and increased risk to osteoporotic fractures.Osteoporosis is prevalent in the middle-aged and elderly population,especia...Osteoporosis as a systemic chronic skeletal disease is characterized by low bone mineral density and increased risk to osteoporotic fractures.Osteoporosis is prevalent in the middle-aged and elderly population,especially in the postmenopausal women.With population aging,osteoporosis has become a world-wide serious public health problem.Early recognition of the high-risk population followed by timely and efficient intervention and/or treatment is important for preventing osteoporotic fractures.In light of the high heritability and complex pathogenesis of osteoporosis,comprehensive consideration of vital biological/biochemical factors is necessary for accurate risk evaluation of fractures.For this purpose,we review recent research progress on molecules which can be applied to assess risk for osteoporotic fractures.Future integrative analyses and systematic evaluation of these molecules may facilitate developing novel methodologies and/or test strategies,i.e.,biochips,for early recognition of osteoporosis,hence contributing to preventing osteoporotic fractures.展开更多
Multidisciplinary team (MDT) model is a diagnostic and treatment model characterized by interdisciplinarity, integration, centralism, individualization, and precision and is becoming more common in the management of...Multidisciplinary team (MDT) model is a diagnostic and treatment model characterized by interdisciplinarity, integration, centralism, individualization, and precision and is becoming more common in the management of complex malignancies. MDT emphasizes team spirit and a personalized treatment strategy according to the actual condition of each patient. A cooperative and effective multidisciplinary team is an important guarantee for delivering high-quality services to patients. Under the guidance of a medical humanistic concept, MDT provides reasonable, effective, convenient, and a full range of excellent quality medical service to patients. The MDT maximizes patient benefits, and it is the developmental direction for large-scale general hospitals. At the same time, the MDT is also an important measure to strengthen the core competitiveness of hospitals. Here, we introduce the clinical application of the model in tumor therapy as well as the current state and development in our hospital.展开更多
Hepatocellular carcinoma (HCC) is one of the most deadly tumors and its incidence has been rising worldwide. In its various stages, several modalities of treatment and therapies have been developed. Appropriate HCC tr...Hepatocellular carcinoma (HCC) is one of the most deadly tumors and its incidence has been rising worldwide. In its various stages, several modalities of treatment and therapies have been developed. Appropriate HCC treatment needs to consider the tumor stage, underlying liver disease and patient’s performance levels. Liver transplantation is an effective treatment but unreliable due to scarcity of donors, whereas surgical resection possesses the potential to achieve long-term survival. However, most tumors are not resectable due to their size, location, number and the function of the liver being compromised. Thus, resection is the first choice treatment for resectable tumors only. This prompts the rise of transarterial chemoembolization (TACE) for unresectable HCC. Progressively, radiofrequency ablation (RFA) arose though it exhibits high postoperative recurrence and cancer mortality. Notably, identifying the best-suited treatment is critical in enabling maximum long-term survival. Though HCC is an identified chemoresistant tumor, chemotherapies have been developed for advanced HCC. Among them, sorafenib, blocks tumor cell proliferation thus improving patient survival, even though costly. In comparison to RFA, TACE has been identified to have more complications and symptoms. However, it demonstrates improved survival benefits and quality of patient care more than symptomatic supportive care. Furthermore, for unresectable HCC, TACE can replace the costly and modestly effective sorafenib treatment;whereas RFA is potentially curative in treating HCC and an alternative to liver transplantation or surgical resection in the early HCC stages. It treats primary and secondary liver tumor in the very early stage HCC. Its reliance on image guidance is minimally invasive and enhances its efficacy and safety, especially where surgery will not have been possible. However, skin burns, hemorrhage, hepatic abscess and pleural effusion are complications that accompany RFA prompting the need for additional treatment.展开更多
Germanium diselenide(GeSe_(2))is a promising candidate for electronic devices because of its unique crystal structure and optoelectronic properties.However,the evolution of lattice and electronic structure ofβ-GeSe_(...Germanium diselenide(GeSe_(2))is a promising candidate for electronic devices because of its unique crystal structure and optoelectronic properties.However,the evolution of lattice and electronic structure ofβ-GeSe_(2)at high pressure is still uncertain.Here we prepared high-qualityβ-GeSe_(2)single crystals by chemical vapor transfer(CVT)technique and performed systematic experimental studies on the evolution of lattice structure and bandgap ofβ-GeSe_(2)under pressure.High-precision high-pressure ultra low frequency(ULF)Raman scattering and synchrotron angle-dispersive x-ray diffraction(ADXRD)measurements support that no structural phase transition exists under high pressure up to 13.80 GPa,but the structure ofβ-GeSe_(2)turns into a disordered state near 6.91 GPa and gradually becomes amorphous forming an irreversibly amorphous crystal at 13.80 GPa.Two Raman modes keep softening abnormally upon pressure.The bandgap ofβ-GeSe_(2)reduced linearly from 2.59 eV to 1.65 eV under pressure with a detectable narrowing of 36.5%,and the sample under pressure performs the piezochromism phenomenon.The bandgap after decompression is smaller than that in the atmospheric pressure environment,which is caused by incomplete recrystallization.These results enrich the insight into the structural and optical properties ofβ-GeSe_(2)and demonstrate the potential of pressure in modulating the material properties of two-dimensional(2D)Ge-based binary material.展开更多
In this paper, we study the relations between trace inequalities(Sobolev and Moser-Trudinger types), isocapacitary inequalities, and the regularity of the complex Hessian and Monge-Amp`ere equations with respect to a ...In this paper, we study the relations between trace inequalities(Sobolev and Moser-Trudinger types), isocapacitary inequalities, and the regularity of the complex Hessian and Monge-Amp`ere equations with respect to a general nonnegative Borel measure. We obtain a quantitative characterization for these relations through the properties of the capacity-minimizing functions.展开更多
In this paper,we use the Sobolev type inequality in Wang et al.(Moser-Trudinger inequality for the complex Monge-Ampère equation,arXiv:2003.06056 v1(2020))to establish the uniform estimate and the Hölder con...In this paper,we use the Sobolev type inequality in Wang et al.(Moser-Trudinger inequality for the complex Monge-Ampère equation,arXiv:2003.06056 v1(2020))to establish the uniform estimate and the Hölder continuity for solutions to the com-plex Monge-Ampère equation with the right-hand side in Lp for any given p>1.Our proof uses various PDE techniques but not the pluripotential theory.展开更多
The stick-slip action of strike-slip faults poses a significant threat to the safety and stability of underground structures.In this study,the north-east area of the Longmenshan fault,Sichuan,provides the geological b...The stick-slip action of strike-slip faults poses a significant threat to the safety and stability of underground structures.In this study,the north-east area of the Longmenshan fault,Sichuan,provides the geological background;the rheological characteristics of the crustal lithosphere and the nonlinear interactions between plates are described by Burger’s viscoelastic constitutive model and the friction constitutive model,respectively.A large-scale global numerical model for plate squeezing analysis is established,and the seemingly periodic stick-slip action of faults at different crust depths is simulated.For a second model at a smaller scale,a local finite element model(sub-model),the time history of displacement at a ground level location on the Longmenshan fault plane in a stick-slip action is considered as the displacement loading.The integration of these models,creating a multi-scale modeling method,is used to evaluate the crack propagation and mechanical response of a tunnel subjected to strike-slip faulting.The determinations of the recurrence interval of stick-slip action and the cracking characteristics of the tunnel are in substantial agreement with the previous field investigation and experimental results,validating the multi-scale modeling method.It can be concluded that,regardless of stratum stiffness,initial cracks first occur at the inverted arch of the tunnel in the footwall,on the squeezed side under strike-slip faulting.The smaller the stratum stiffness is,the smaller the included angle between the crack expansion and longitudinal direction of the tunnel,and the more extensive the crack expansion range.For the tunnel in a high stiffness stratum,both shear and bending failures occur on the lining under strike-slip faulting,while for that in the low stiffness stratum,only bending failure occurs on the lining.展开更多
In order to solve the problem of poor teaching quality caused by classroom teachers’inability to grasp students’dynamics in time,this paper designs a feedback system for classroom attention with the help of the rese...In order to solve the problem of poor teaching quality caused by classroom teachers’inability to grasp students’dynamics in time,this paper designs a feedback system for classroom attention with the help of the research on expression recognition technology in deep learning.In the real-time analysis of expression,although the deeper deep learning network has more accurate recognition effect,there are drawbacks of too large model and too many parameters in the network training process.In this paper,we propose a student concentration algorithm that uses the Convolutional Block attentional module(CBAM)and the Local Binary Pattern(LBP)to reduce the number of parameters in the model by replacing the convolution with the depthseparable convolution LBP preprocessing enhances the feature validity of the input feature map and improves the training speed and accuracy of the model.The experimental results show that the algorithm has a good discriminating effect on expression recognition,and the model is small.展开更多
基金supported by the Key Research and Development Project in Shaanxi Province (2023GXLH-024)the National Natural Science Foundation of China (62250009,62002282,62037001,and 62192781).
文摘Tax risk behavior causes serious loss of fiscal revenue,damages the country’s public infrastructure,and disturbs the market economic order of fair competition.In recent years,tax risk detection,driven by information technology such as data mining and artificial intelligence,has received extensive attention.To promote the high-quality development of tax risk detection methods,this paper provides the first comprehensive overview and summary of existing tax risk detection methods worldwide.More specifi-cally,it first discusses the causes and negative impacts of tax risk behaviors,along with the development of tax risk detection.It then focuses on data-mining-based tax risk detection methods utilized around the world.Based on the different principles employed by the algorithms,existing risk detection methods can be divided into two categories:relationship-based and non-relationship-based.A total of 14 risk detection methods are identified,and each method is thoroughly explored and analyzed.Finally,four major technical bottlenecks of current data-driven tax risk detection methods are analyzed and discussed,including the difficulty of integrating and using fiscal and tax fragmented knowledge,unexplainable risk detection results,the high cost of risk detection algorithms,and the reliance of existing algorithms on labeled information.After investigating these issues,it is concluded that knowledge-guided and datadriven big data knowledge engineering will be the development trend in the field of tax risk in the future;that is,the gradual transition of tax risk detection from informatization to intelligence is the future development direction.
基金the National Key R&D Program of China(GrantNo.2021YFA1601104)National KeyR&DProgram of China(GrantNo.2022YFA16038004)+1 种基金National Key R&D Program of China(Grant No.2022YFA16038002)National Science and Technology Major Project of China(No.J2019-VI-0004-0117).
文摘Scanning electron microscopy(SEM)is a crucial tool in the field of materials science,providing valuable insightsinto the microstructural characteristics of materials.Unfortunately,SEM images often suffer from blurrinesscaused by improper hardware calibration or imaging automation errors,which present challenges in analyzingand interpretingmaterial characteristics.Consequently,rectifying the blurring of these images assumes paramountsignificance to enable subsequent analysis.To address this issue,we introduce a Material Images DeblurringNetwork(MIDNet)built upon the foundation of the Nonlinear Activation Free Network(NAFNet).MIDNetis meticulously tailored to address the blurring in images capturing the microstructure of materials.The keycontributions include enhancing the NAFNet architecture for better feature extraction and representation,integratinga novel soft attention mechanism to uncover important correlations between encoder and decoder,andintroducing newmulti-loss functions to improve training effectiveness and overallmodel performance.We conducta comprehensive set of experiments utilizing the material blurry dataset and compare them to several state-of-theartdeblurring methods.The experimental results demonstrate the applicability and effectiveness of MIDNet in thedomain of deblurring material microstructure images,with a PSNR(Peak Signal-to-Noise Ratio)reaching 35.26 dBand an SSIM(Structural Similarity)of 0.946.Our dataset is available at:https://github.com/woshigui/MIDNet.
基金supported by the National Key Research and Development Program of China(Grant Nos.2021YFA1400200 and2021YFA0718701)the National Natural Science Foundation of China(Grant Nos.U2032127,11904322,12104411,12174347)+4 种基金the Natural Science Foundation of Henan province of China(Grant No.202300410356)the China Postdoctoral Science Foundation(Grant Nos.2019M652560 and 2020M682326)the CAS Interdisciplinary Innovation Team(Grant No.JCTD-2019-01)the Postdoctoral Research Grant in Henan Province(Grant No.1902013)the Science Foundation for Highlevel Talents of Wuyi University(Grant No.2021AL019)。
文摘The Cs_(2)NaInCl_(6) double perovskite is one of the most promising lead-free perovskites due to its exceptional stability and straightforward synthesis.However,it faces challenges related to inefficient photoluminescence.Doping and high pressure are employed to tailor the optical properties of Cs_(2)NaInCl_(6).Herein,Sb^(3+)doped Cs_(2)NaInCl_(6)(Sb^(3+):Cs_(2)NaInCl_(6)) was synthesized and it exhibits blue emission with a photoluminescence quantum yield of up to 37.3%.Further,by employing pressure tuning,a blue stable emission under a very wide range from 2.7 GPa to 9.8 GPa is realized in Sb^(3+):Cs_(2)NaInCl_(6).Subsequently,the emission intensity of Sb^(3+):Cs_(2)NaInCl_(6) experiences a significant increase(3.3 times)at 19.0 GPa.It is revealed that the pressure-induced distinct emissions can be attributed to the carrier self-trapping and detrapping between Cs_(2)NaInCl_(6) and Sb^(3+).Notably,the lattice compression in the cubic phase inevitably modifies the band gap of Sb^(3+):Cs_(2)NaInCl_(6).Our findings provide valuable insights into effects of the high pressure in further boosting unique emission characteristics but also offer promising opportunities for development of doped double perovskites with enhanced optical functionalities.
基金support from the U.S.Dept.of Energy,Office of Basic Energy Sciences Project FWP 06SCPE401support from the National Science Foundation under Grant Number 2051390the financial support from the National Science Foundation CMMI-1723539,the financial support from the National Science Foundation CMMI-1729829。
文摘In this study,the role of twin-twin interactions on the distributions of local defects(e.g.,dislocations)and stress fields in a magnesium alloy is investigated.A co-zone(1012)-(1012)tensile twin junction in a deformed Mg-3wt.%Y alloy is analyzed using transmission electron microscopy(TEM).The results show that the morphology of the impinging(1012)twin is asymmetric,and the non-interacting boundary of the recipient(1012)twin is irregular.Detailed analysis of TEM images reveals that type-II pyramidal[1213](1212)dislocations concentrate in the vicinity of the twin-twin junction site.The same<c+a>dislocations are also observed inside the interacting twin domains along with a few <a> dislocations.The<c+a>dislocations emanating from the impinging(1012)twin boundary have edge character and are extended with faults parallel to the basal plane.In contrast,the<c+a>dislocations connected to the recipient(1012)twin are predominantly screw orientation and compact.Elasto-viscoplastic fast Fourier transform based crystal plasticity calculations are performed to rationalize the observed twin morphology and local dislocation distribution.The model calculations suggest that the local stress fields generated at the junction site where the two twins meet are responsible for the experimentally observed concentration of<c+a>dislocations.The calculated stress fields are asymmetric with respect to the junction site,explaining the observed asymmetric morphology of the impinging twin.Overall,these findings show strong effects of twin-twin interactions on the distribution of dislocations as well as the evolution of the twinned microstructure and as such,can help advance understanding of twinning in Mg alloys and their effect on mechanical behavior.
基金the Startup Fund from Soochow University(Q413900712)the Project of the Priority Academic Program Development of Jiangsu Higher Education Institution.
文摘Osteoporosis as a systemic chronic skeletal disease is characterized by low bone mineral density and increased risk to osteoporotic fractures.Osteoporosis is prevalent in the middle-aged and elderly population,especially in the postmenopausal women.With population aging,osteoporosis has become a world-wide serious public health problem.Early recognition of the high-risk population followed by timely and efficient intervention and/or treatment is important for preventing osteoporotic fractures.In light of the high heritability and complex pathogenesis of osteoporosis,comprehensive consideration of vital biological/biochemical factors is necessary for accurate risk evaluation of fractures.For this purpose,we review recent research progress on molecules which can be applied to assess risk for osteoporotic fractures.Future integrative analyses and systematic evaluation of these molecules may facilitate developing novel methodologies and/or test strategies,i.e.,biochips,for early recognition of osteoporosis,hence contributing to preventing osteoporotic fractures.
基金supported by a grant (No. Z151100002615031) from the Project of Science and Technology in Beijing, China
文摘Multidisciplinary team (MDT) model is a diagnostic and treatment model characterized by interdisciplinarity, integration, centralism, individualization, and precision and is becoming more common in the management of complex malignancies. MDT emphasizes team spirit and a personalized treatment strategy according to the actual condition of each patient. A cooperative and effective multidisciplinary team is an important guarantee for delivering high-quality services to patients. Under the guidance of a medical humanistic concept, MDT provides reasonable, effective, convenient, and a full range of excellent quality medical service to patients. The MDT maximizes patient benefits, and it is the developmental direction for large-scale general hospitals. At the same time, the MDT is also an important measure to strengthen the core competitiveness of hospitals. Here, we introduce the clinical application of the model in tumor therapy as well as the current state and development in our hospital.
文摘Hepatocellular carcinoma (HCC) is one of the most deadly tumors and its incidence has been rising worldwide. In its various stages, several modalities of treatment and therapies have been developed. Appropriate HCC treatment needs to consider the tumor stage, underlying liver disease and patient’s performance levels. Liver transplantation is an effective treatment but unreliable due to scarcity of donors, whereas surgical resection possesses the potential to achieve long-term survival. However, most tumors are not resectable due to their size, location, number and the function of the liver being compromised. Thus, resection is the first choice treatment for resectable tumors only. This prompts the rise of transarterial chemoembolization (TACE) for unresectable HCC. Progressively, radiofrequency ablation (RFA) arose though it exhibits high postoperative recurrence and cancer mortality. Notably, identifying the best-suited treatment is critical in enabling maximum long-term survival. Though HCC is an identified chemoresistant tumor, chemotherapies have been developed for advanced HCC. Among them, sorafenib, blocks tumor cell proliferation thus improving patient survival, even though costly. In comparison to RFA, TACE has been identified to have more complications and symptoms. However, it demonstrates improved survival benefits and quality of patient care more than symptomatic supportive care. Furthermore, for unresectable HCC, TACE can replace the costly and modestly effective sorafenib treatment;whereas RFA is potentially curative in treating HCC and an alternative to liver transplantation or surgical resection in the early HCC stages. It treats primary and secondary liver tumor in the very early stage HCC. Its reliance on image guidance is minimally invasive and enhances its efficacy and safety, especially where surgery will not have been possible. However, skin burns, hemorrhage, hepatic abscess and pleural effusion are complications that accompany RFA prompting the need for additional treatment.
基金the National Natural Science Foundation of China(Grant Nos.12004339,11874328,11904322,61804047,22071221,and 21905252)China Postdoctoral Science Foundation(Grant Nos.2018M640679 and 2019T120629)the Zhongyuan Academician Foundation(Grant No.ZYQR201810163)。
文摘Germanium diselenide(GeSe_(2))is a promising candidate for electronic devices because of its unique crystal structure and optoelectronic properties.However,the evolution of lattice and electronic structure ofβ-GeSe_(2)at high pressure is still uncertain.Here we prepared high-qualityβ-GeSe_(2)single crystals by chemical vapor transfer(CVT)technique and performed systematic experimental studies on the evolution of lattice structure and bandgap ofβ-GeSe_(2)under pressure.High-precision high-pressure ultra low frequency(ULF)Raman scattering and synchrotron angle-dispersive x-ray diffraction(ADXRD)measurements support that no structural phase transition exists under high pressure up to 13.80 GPa,but the structure ofβ-GeSe_(2)turns into a disordered state near 6.91 GPa and gradually becomes amorphous forming an irreversibly amorphous crystal at 13.80 GPa.Two Raman modes keep softening abnormally upon pressure.The bandgap ofβ-GeSe_(2)reduced linearly from 2.59 eV to 1.65 eV under pressure with a detectable narrowing of 36.5%,and the sample under pressure performs the piezochromism phenomenon.The bandgap after decompression is smaller than that in the atmospheric pressure environment,which is caused by incomplete recrystallization.These results enrich the insight into the structural and optical properties ofβ-GeSe_(2)and demonstrate the potential of pressure in modulating the material properties of two-dimensional(2D)Ge-based binary material.
基金supported by China Postdoctoral Science Foundation (Grant No. BX2021015)supported by National Key R&D Program of China (Grant No. SQ2020YFA0712800)National Natural Science Foundation of China (Grant No. 11822101)。
文摘In this paper, we study the relations between trace inequalities(Sobolev and Moser-Trudinger types), isocapacitary inequalities, and the regularity of the complex Hessian and Monge-Amp`ere equations with respect to a general nonnegative Borel measure. We obtain a quantitative characterization for these relations through the properties of the capacity-minimizing functions.
文摘In this paper,we use the Sobolev type inequality in Wang et al.(Moser-Trudinger inequality for the complex Monge-Ampère equation,arXiv:2003.06056 v1(2020))to establish the uniform estimate and the Hölder continuity for solutions to the com-plex Monge-Ampère equation with the right-hand side in Lp for any given p>1.Our proof uses various PDE techniques but not the pluripotential theory.
基金supported by the Key Projects for International Science and Technology Innovation Cooperation between Governments(No.2022YFE0104300)National Natural Science Foundation of China(Grant No.52130808)+1 种基金Scientific and Technical Exploitation Program of China Railway Design Corporation(No.2020YY240610)Scientific and Technical Exploitation Program of China Railway(No.K2020G033).
文摘The stick-slip action of strike-slip faults poses a significant threat to the safety and stability of underground structures.In this study,the north-east area of the Longmenshan fault,Sichuan,provides the geological background;the rheological characteristics of the crustal lithosphere and the nonlinear interactions between plates are described by Burger’s viscoelastic constitutive model and the friction constitutive model,respectively.A large-scale global numerical model for plate squeezing analysis is established,and the seemingly periodic stick-slip action of faults at different crust depths is simulated.For a second model at a smaller scale,a local finite element model(sub-model),the time history of displacement at a ground level location on the Longmenshan fault plane in a stick-slip action is considered as the displacement loading.The integration of these models,creating a multi-scale modeling method,is used to evaluate the crack propagation and mechanical response of a tunnel subjected to strike-slip faulting.The determinations of the recurrence interval of stick-slip action and the cracking characteristics of the tunnel are in substantial agreement with the previous field investigation and experimental results,validating the multi-scale modeling method.It can be concluded that,regardless of stratum stiffness,initial cracks first occur at the inverted arch of the tunnel in the footwall,on the squeezed side under strike-slip faulting.The smaller the stratum stiffness is,the smaller the included angle between the crack expansion and longitudinal direction of the tunnel,and the more extensive the crack expansion range.For the tunnel in a high stiffness stratum,both shear and bending failures occur on the lining under strike-slip faulting,while for that in the low stiffness stratum,only bending failure occurs on the lining.
基金Key research Project of higher education institutions in Henan Province(Project:Name:A Study on Students’concentration in Class Based on Deep Multi-task Learning Framework,Project No.23B413004).
文摘In order to solve the problem of poor teaching quality caused by classroom teachers’inability to grasp students’dynamics in time,this paper designs a feedback system for classroom attention with the help of the research on expression recognition technology in deep learning.In the real-time analysis of expression,although the deeper deep learning network has more accurate recognition effect,there are drawbacks of too large model and too many parameters in the network training process.In this paper,we propose a student concentration algorithm that uses the Convolutional Block attentional module(CBAM)and the Local Binary Pattern(LBP)to reduce the number of parameters in the model by replacing the convolution with the depthseparable convolution LBP preprocessing enhances the feature validity of the input feature map and improves the training speed and accuracy of the model.The experimental results show that the algorithm has a good discriminating effect on expression recognition,and the model is small.