Prostate cancer has gradually risen to become the second most common cancer threatening men’s health, and prostate-specific antigen (PSA), as the main screening indicator for prostate cancer, has the defects of low s...Prostate cancer has gradually risen to become the second most common cancer threatening men’s health, and prostate-specific antigen (PSA), as the main screening indicator for prostate cancer, has the defects of low specificity and insufficient diagnostic efficacy. As a novel inflammatory index based on neutrophil, lymphocyte and platelet counts, the systemic immune-inflammation index (SII) has recently become a more powerful biomarker for predicting the occurrence and progression of various malignancies. SII reflects the systemic inflammatory response of prostate cancer patients in a more balanced manner, and has higher predictive value than neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR). High SII values are often associated with cancer progression and poor prognosis. This article reviews the research progress of SII in prostate cancer, in order to provide guidance for clinical practice.展开更多
Carbon quantum dots (CQDs) have been used in memristors due to their attractive optical and electronic properties, which are considered candidates for brain-inspired computing devices. In this work, the performance of...Carbon quantum dots (CQDs) have been used in memristors due to their attractive optical and electronic properties, which are considered candidates for brain-inspired computing devices. In this work, the performance of CQDs-based memristors is improved by utilizing nitrogen-doping. In contrast, nitrogen-doped CQDs (N-CQDs)-based optoelectronic memristors can be driven with smaller programming voltages (−0.6 to 0.7 V) and exhibit lower powers (78 nW/0.29 µW). The physical mechanism can be attributed to the reversible transition between C–N and C=N with lower binding energy induced by the electric field and the generation of photogenerated carriers by ultraviolet light irradiation, which adjusts the conductivity of the initial N-CQDs to implement resistance switching. Importantly, the convolutional image processing based on various cross kernels is efficiently demonstrated by stable multi-level storage properties. An N-CQDs-based optoelectronic reservoir computing implements impressively high accuracy in both no noise and various noise modes when recognizing the Modified National Institute of Standards and Technology (MNIST) dataset. It illustrates that N-CQDs-based memristors provide a novel strategy for developing artificial vision system with integrated in-memory sensor and computing.展开更多
Developing wide-temperature and high-safety lithium-ion batteries(LIBs)presents significant challenges attributed to the absence of suitable solvents possessing broad liquid range and non-flammability properties.γ-Bu...Developing wide-temperature and high-safety lithium-ion batteries(LIBs)presents significant challenges attributed to the absence of suitable solvents possessing broad liquid range and non-flammability properties.γ-Butyrolactone(GBL)has emerged as a promising solvent;however,its incompatibility with graphite anode has hindered its application.This limitation necessitates a comprehensive investigation into the underlying mechanisms and potential solutions.In this study,we achieve a molecular-level understanding of the perplexing interphase formation process by employing in-situ spectroelectrochemical techniques and density function calculations.Our findings reveal that,even at high salt concentrations,GBL consistently occupies the primary Li^(+)solvation sheath,leading to extensive GBL decomposition and the formation of a high-impedance and inorganic-poor solid-electrolyte interphase(SEI)layer.Contrary to manipulating solvation structures,our research demonstrates that the utilization of filmforming additives with higher reduction potential facilitates the pre-establishment of a robust SEI film on the graphite anode.This approach effectively inhibits GBL decomposition and significantly enhances the battery's lifespan.This study provides the first reported intrinsic understanding of the unique GBLgraphite incompatibility and offers valuable insights for the development of wide-temperature and high-safety LIBs.展开更多
Recently,deep learning-based image inpainting methods have made great strides in reconstructing damaged regions.However,these methods often struggle to produce satisfactory results when dealing with missing images wit...Recently,deep learning-based image inpainting methods have made great strides in reconstructing damaged regions.However,these methods often struggle to produce satisfactory results when dealing with missing images with large holes,leading to distortions in the structure and blurring of textures.To address these problems,we combine the advantages of transformers and convolutions to propose an image inpainting method that incorporates edge priors and attention mechanisms.The proposed method aims to improve the results of inpainting large holes in images by enhancing the accuracy of structure restoration and the ability to recover texture details.This method divides the inpainting task into two phases:edge prediction and image inpainting.Specifically,in the edge prediction phase,a transformer architecture is designed to combine axial attention with standard self-attention.This design enhances the extraction capability of global structural features and location awareness.It also balances the complexity of self-attention operations,resulting in accurate prediction of the edge structure in the defective region.In the image inpainting phase,a multi-scale fusion attention module is introduced.This module makes full use of multi-level distant features and enhances local pixel continuity,thereby significantly improving the quality of image inpainting.To evaluate the performance of our method.comparative experiments are conducted on several datasets,including CelebA,Places2,and Facade.Quantitative experiments show that our method outperforms the other mainstream methods.Specifically,it improves Peak Signal-to-Noise Ratio(PSNR)and Structure Similarity Index Measure(SSIM)by 1.141~3.234 db and 0.083~0.235,respectively.Moreover,it reduces Learning Perceptual Image Patch Similarity(LPIPS)and Mean Absolute Error(MAE)by 0.0347~0.1753 and 0.0104~0.0402,respectively.Qualitative experiments reveal that our method excels at reconstructing images with complete structural information and clear texture details.Furthermore,our model exhibits impressive performance in terms of the number of parameters,memory cost,and testing time.展开更多
The equipment used in various fields contains an increasing number of parts with curved surfaces of increasing size.Five-axis computer numerical control(CNC)milling is the main parts machining method,while dynamics an...The equipment used in various fields contains an increasing number of parts with curved surfaces of increasing size.Five-axis computer numerical control(CNC)milling is the main parts machining method,while dynamics analysis has always been a research hotspot.The cutting conditions determined by the cutter axis,tool path,and workpiece geometry are complex and changeable,which has made dynamics research a major challenge.For this reason,this paper introduces the innovative idea of applying dimension reduction and mapping to the five-axis machining of curved surfaces,and proposes an efficient dynamics analysis model.To simplify the research object,the cutter position points along the tool path were discretized into inclined plane five-axis machining.The cutter dip angle and feed deflection angle were used to define the spatial position relationship in five-axis machining.These were then taken as the new base variables to construct an abstract two-dimensional space and establish the mapping relationship between the cutter position point and space point sets to further simplify the dimensions of the research object.Based on the in-cut cutting edge solved by the space limitation method,the dynamics of the inclined plane five-axis machining unit were studied,and the results were uniformly stored in the abstract space to produce a database.Finally,the prediction of the milling force and vibration state along the tool path became a data extraction process that significantly improved efficiency.Two experiments were also conducted which proved the accuracy and efficiency of the proposed dynamics analysis model.This study has great potential for the online synchronization of intelligent machining of large surfaces.展开更多
Objective:To explore the application effect of virtual simulation experiment combined with picture archiving and communication system(PACS)in medical imaging practical teaching.Methods:97 students from the medical ima...Objective:To explore the application effect of virtual simulation experiment combined with picture archiving and communication system(PACS)in medical imaging practical teaching.Methods:97 students from the medical imaging class of 2022 were divided into two groups;the control group(n=48)was taught by the traditional teaching method,whereas the research group was taught by virtual simulation experiment combined with PACS(n=49).The teaching achievements and teaching effects of the two groups were compared to define the advantages of the two teaching modes.Results:Initially,there were no significant differences in the basic theory,image analysis,report writing,and differential diagnosis scores between the two groups of students(P>0.05);however,after 16 weeks of teaching,the scores of the research group were better than those of the control group(P<0.05);the pass rate of students in the study group(93.88%)was higher than that in the control group(81.25%);the scores of students in the research group in terms of clinical inquiry skills,X-ray/computed tomography/magnetic resonance imaging(X-ray/CT/MRI)operation skills,and doctor-patient communication skills were significantly higher than those in the control group(P<0.05).Conclusion:In medical imaging practical teaching,the application of virtual simulation experiment combined with PACS can effectively address several problems in the traditional teaching mode,including the single teaching method,the single teaching content,and the lack of innovation,and,at the same time,improve students’basic theoretical knowledge,X-ray/CT/MRI operation skills,consultation skills,and doctor-patient communication skills,thereby effectively improving the teaching quality and learning effect.展开更多
Fatigue has negative impacts on the general working population as well as on seafarers. In order to study seafarers’ fatigue, a questionnaire-base survey was conducted to gain information about potential risk factors...Fatigue has negative impacts on the general working population as well as on seafarers. In order to study seafarers’ fatigue, a questionnaire-base survey was conducted to gain information about potential risk factors for fatigue and construct indexes indicating fatigue. The study applies T-test to compare strata of seafarers to analyse work and sleep patterns in global seafaring. Qualitative analysis are also employed to explore the impacts of fatigue on seafarer’s occupational health and safety.展开更多
Photocatalytic H2 evolution reactions on pristine graphitic carbon nitrides(g-C3N4),as a promising approach for converting solar energy to fuel,are attractive for tackling global energy concerns but still suffer from ...Photocatalytic H2 evolution reactions on pristine graphitic carbon nitrides(g-C3N4),as a promising approach for converting solar energy to fuel,are attractive for tackling global energy concerns but still suffer from low efficiencies.In this article,we report a tractable approach to modifying g-C3N4 with vanadyl phthalocyanine(VOPc/CN)for efficient visible-light-driven hydrogen production.A non-covalent VOPc/CN hybrid photocatalyst formed viaπ-πstacking interactions between the two components,as confirmed by analysis of UV-vis absorption spectra.The VOPc/CN hybrid photocatalyst shows excellent visible-light-driven photocatalytic performance and good stability.Under optimal conditions,the corresponding H2 evolution rate is nearly 6 times higher than that of pure g-C3N4.The role of VOPc in promoting hydrogen evolution activity was to extend the visible light absorption range and prevent the recombination of photoexcited electron-hole pairs effectively.It is expected that this facile modification method could be a new inspiration for the rational design and exploration of g-C3N4-based hybrid systems with strong light absorption and high-efficiency carrier separation.展开更多
The vibration propagates through the shaft in the form of elastic waves. The propagation characteristics of the elastic waves are a ected by the axial loads. The influence of the axial loads to the propagation charact...The vibration propagates through the shaft in the form of elastic waves. The propagation characteristics of the elastic waves are a ected by the axial loads. The influence of the axial loads to the propagation characteristics of the elastic waves is studied in this paper. Firstly, the transfer matrix of the elastic waves for the non-uniform shaft with axial loads is deduced by combining the transfer matrix without axial load and the additional equation caused by the axial load. And then, a numerical method is used to study the influence of the axial load, non-uniformity and the rotating speed to the propagation characteristics of the elastic waves. It’s found that a new Stop Band will appear due to the axial force, and the central frequency of which will decrease as the increase of the force, while the band width of which remains the same. The central frequency of the new Stop Band will also increase as the increase of the cross-section area ratio;however, the rotating speed of the shaft doesn’t a ect the propagation characteristics of the elastic waves obviously. Finally, an experimental rig is built up for further study, even though there are some small local errors, the results of experiments match well with the numerical ones, which indicates the validation of the theoretical results. The result can help to study the influence of the axial load to the dynamics of a non-uniform shaft and help to reveal the vibration propagating mechanism in such a shaft.展开更多
Initial residual stress is the main reason causing machining deformation of the workpiece,which has been deemed as one of the most important aspects of machining quality issues.The inference of the distribution of ini...Initial residual stress is the main reason causing machining deformation of the workpiece,which has been deemed as one of the most important aspects of machining quality issues.The inference of the distribution of initial residual stress inside the blank has significant meaning for machining deformation control.Due to the principle error of existing residual stress detection methods,there are still challenges in practical applications.Aiming at the detection problem of the initial residual stress field,an initial residual stress inference method by incorporating monitoring data and mechanism model is proposed in this paper.Monitoring data during machining process is used to represent the macroscopic characterization of the unbalanced residual stress,and the finite element numerical model is used as the mechanism model so as to solve the problem that the analytic mechanism model is difficult to establish;the policy gradient approach is introduced to solve the gradient descent problem of the combination of learning model and mechanism model.Finally,the initial residual stress field is obtained through iterative calculation based on the fusing method of monitoring data and mechanism model.Verification results show that the proposed inference method of initial residual stress field can accurately and effectively reflect the machining deformation in the actual machining process.展开更多
In order to investigate the effect of influent condition heterogeneity on diversity of the bacterial community,the degree of microbial resolution and effluent quality,biological treatment of micro-polluted source wate...In order to investigate the effect of influent condition heterogeneity on diversity of the bacterial community,the degree of microbial resolution and effluent quality,biological treatment of micro-polluted source water is proposed. Scanning Electron Microscopy( SEM) analysis reflects that influent conditions change the morphologies of biofilm. Denaturing Gradient Gel Electrophoresis( DGGE) analysis shows differences of H values are due to succession of functional bacterial communities. Microbial resolution values and species identifications reveal organic carbon is the main cause of community differentiation and bacterial migration.展开更多
By using an improved Bridgman method,0.3 mol%Tm^(3+)/0.6 mol%Tb^(3+)/y mol%Eu^(3+)(y=0,0.4,0.6,0.8)doped Na_(5)Y_(9)F_(32)single crystals were prepared.The x-ray diffraction,excitation spectra,emission spectra and flu...By using an improved Bridgman method,0.3 mol%Tm^(3+)/0.6 mol%Tb^(3+)/y mol%Eu^(3+)(y=0,0.4,0.6,0.8)doped Na_(5)Y_(9)F_(32)single crystals were prepared.The x-ray diffraction,excitation spectra,emission spectra and fluorescence decay curves were used to explore the crystal structure and optical performance of the obtained samples.When excited by 362 nm light,the cool white emission was realized by Na_(5)Y_(9)F_(32)single crystal triply-doped with 0.3 mol%Tm^(3+)/0.6 mol%Tb^(3+)/0.8 mol%Eu^(3+),in which the Commission Internationale de l’Eclairage(CIE)chromaticity coordinate was(0.2995,0.3298)and the correlated color temperature(CCT)was 6586 K.The integrated normalized emission intensity of the tridoped single crystal at 448 K could keep 62%of that at 298 K.The internal quantum yield(QY)was calculated to be~15.16%by integrating spheres.These results suggested that the single crystals tri-doped with Tm^(3+),Tb^(3+)and Eu^(3+)ions have a promising potential application for white light-emitting diodes(w-LEDs).展开更多
Precise control of machining deformation is crucial for improving the manufacturing quality of structural aerospace components.In the machining process,different batches of blanks have different residual stress distri...Precise control of machining deformation is crucial for improving the manufacturing quality of structural aerospace components.In the machining process,different batches of blanks have different residual stress distributions,which pose a significant challenge to machining deformation control.In this study,a reinforcement learning method for machining deformation control based on a meta-invariant feature space was developed.The proposed method uses a reinforcement-learning model to dynamically control the machining process by monitoring the deformation force.Moreover,combined with a meta-invariant feature space,the proposed method learns the internal relationship of the deformation control approaches under different stress distributions to achieve the machining deformation control of different batches of blanks.Finally,the experimental results show that the proposed method achieves better deformation control than the two existing benchmarking methods.展开更多
The purpose of this paper is to study the air pollutants in Xiong’an New Area based on MATLAB grey model [1]. From 2011 to 2016, the results of sulfur dioxide (SO2), nitrogen dioxide (NO2) and inhalable particulate m...The purpose of this paper is to study the air pollutants in Xiong’an New Area based on MATLAB grey model [1]. From 2011 to 2016, the results of sulfur dioxide (SO2), nitrogen dioxide (NO2) and inhalable particulate matter (PM1O) detected at monitoring points in the three counties of Xiong’an were analyzed. According to the national environmental air quality standard [2], the air quality in Xiong’an New Area was reasonably evaluated based on grey model in MATLAB. Judging from the weight of pollution factors in the model, sulfur dioxide (SO2) is the controlling factor of air quality in Xiong’an New Area, and the weight of nitrogen dioxide (NO2) gradually increases. The main sources of the three pollutants were obtained by comprehensive data analysis, and a grey model was established according to the mass concentration of the main air pollutants, and the grey forecasting model was tested. The experimental results show that the model can be effectively applied to the forecasting of ambient air quality. On this basis, the present situation of atmospheric environmental quality in Xiong’an New Area and suggestions for improvement are obtained.展开更多
The accelerated arriving of 5G era has brought a new round of intelligent transformation which will completely emancipate smart terminal devices.While the subsequent deleterious effect of electromagnetic wave on elect...The accelerated arriving of 5G era has brought a new round of intelligent transformation which will completely emancipate smart terminal devices.While the subsequent deleterious effect of electromagnetic wave on electronic devices is increasingly serious,driving the growth of next-generation electromagnetic wave absorbents.As a tactful combination of components and structures,three-dimensional(3D)macroscopic absorbents with fascinating synergy afford exceptional electromagnetic wave absorption,and tremendous efforts have been devoted to this investigation.However,in terms of macroscopic absorbents and their synergistic effect,few reviews are proposed to comb the latest achievements and detailed synergy.This review article focuses on the synergistic effect of macro-architectured absorbents mainly including structure-induced synergy,structure-components synergy,and multiple-components induced synergy.And then the potential construction principles and strategies of macroscopic absorbents are combed.Significantly,the key information for structures and components manipulation including nano-micro design and components regulation is further dissected by critically selected cutting-edge 3D macroscopic absorbents.Moreover,a brief summary of multifunctional electromagnetic wave absorbents(EWAs)-based macroscopic structures is presented.Finally,the development prospects and challenges of these materials are discussed.展开更多
As an emerging information device that adapts to development of the big data era,memristor has attracted much attention due to its advantage in processing massive data.However,the nucleation and growth of conductive f...As an emerging information device that adapts to development of the big data era,memristor has attracted much attention due to its advantage in processing massive data.However,the nucleation and growth of conductive filaments often exhibit randomness and instability,which undoubtedly leads to a wide and discrete range of switching parameters,damaging the electrical performance of device.In this work,a strategy of inserting carbon quantum dots(CQDs)into graphene oxide(GO)resistance layer is utilized to improve the stability of the switching parameters and the reliability of the device is improved.Compared with GO-based devices,GO/CQDs/GO-based devices exhibit a more stable resistance switching curve,low power,lower and more concentrated threshold voltage parameters with lower variation coefficient,faster switching speed,and more stable retention and endurance.The cause-inducing performance improvement may be attributed to the local electric field generated by CQDs in resistance switching that effectively guides the formation and rupture of conductive filaments,which optimizes the effective migration distance of Ag^(+),thereby improving the uniformity of resistance switching.Additionally,a convolutional neural network model is constructed to identify the CIFAR-10 data set,showing the high recognition accuracy of online and offline learning.The cross-kernel structure is used to further implement convolutional image processing through multiplication and accumulation operations.This work provides a solution to improve the performance of memristors,which can contribute to developing digital information processing.展开更多
文摘Prostate cancer has gradually risen to become the second most common cancer threatening men’s health, and prostate-specific antigen (PSA), as the main screening indicator for prostate cancer, has the defects of low specificity and insufficient diagnostic efficacy. As a novel inflammatory index based on neutrophil, lymphocyte and platelet counts, the systemic immune-inflammation index (SII) has recently become a more powerful biomarker for predicting the occurrence and progression of various malignancies. SII reflects the systemic inflammatory response of prostate cancer patients in a more balanced manner, and has higher predictive value than neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR). High SII values are often associated with cancer progression and poor prognosis. This article reviews the research progress of SII in prostate cancer, in order to provide guidance for clinical practice.
基金financially supported by the National Key Research and Development Program of China(No.2022YFE0139100)International cooperative research project of Jiangsu province(No.BZ2022008)+3 种基金the National Natural Science Foundation Project of China(No.62175028)Program 111_2.0 in China(No.BP0719013)Leading Technology of Jiangsu Basic Research Plan(No.BK20192003)Postgraduate Research & Practice Innovation Program of Jiangsu Province,the Fundamental Research Funds for the Central Universities(No.KYCX23_0254).
文摘Carbon quantum dots (CQDs) have been used in memristors due to their attractive optical and electronic properties, which are considered candidates for brain-inspired computing devices. In this work, the performance of CQDs-based memristors is improved by utilizing nitrogen-doping. In contrast, nitrogen-doped CQDs (N-CQDs)-based optoelectronic memristors can be driven with smaller programming voltages (−0.6 to 0.7 V) and exhibit lower powers (78 nW/0.29 µW). The physical mechanism can be attributed to the reversible transition between C–N and C=N with lower binding energy induced by the electric field and the generation of photogenerated carriers by ultraviolet light irradiation, which adjusts the conductivity of the initial N-CQDs to implement resistance switching. Importantly, the convolutional image processing based on various cross kernels is efficiently demonstrated by stable multi-level storage properties. An N-CQDs-based optoelectronic reservoir computing implements impressively high accuracy in both no noise and various noise modes when recognizing the Modified National Institute of Standards and Technology (MNIST) dataset. It illustrates that N-CQDs-based memristors provide a novel strategy for developing artificial vision system with integrated in-memory sensor and computing.
基金financially supported by the National Natural Science Foundation of China(21972049,22272175)the National Key R&D Program of China(2022YFA1504002)+3 种基金the“Scientist Studio Funding”from Tianmu Lake Institute of Advanced Energy Storage Technologies Co.,Ltd.Dalian Supports High-Level Talent Innovation and Entrepreneurship Projects(2021RD14)the Dalian Institute of Chemical Physics(DICP I202213)the 21C Innovation Laboratory,Contemporary Ampere Technology Ltd.by project No.21C-OP-202208。
文摘Developing wide-temperature and high-safety lithium-ion batteries(LIBs)presents significant challenges attributed to the absence of suitable solvents possessing broad liquid range and non-flammability properties.γ-Butyrolactone(GBL)has emerged as a promising solvent;however,its incompatibility with graphite anode has hindered its application.This limitation necessitates a comprehensive investigation into the underlying mechanisms and potential solutions.In this study,we achieve a molecular-level understanding of the perplexing interphase formation process by employing in-situ spectroelectrochemical techniques and density function calculations.Our findings reveal that,even at high salt concentrations,GBL consistently occupies the primary Li^(+)solvation sheath,leading to extensive GBL decomposition and the formation of a high-impedance and inorganic-poor solid-electrolyte interphase(SEI)layer.Contrary to manipulating solvation structures,our research demonstrates that the utilization of filmforming additives with higher reduction potential facilitates the pre-establishment of a robust SEI film on the graphite anode.This approach effectively inhibits GBL decomposition and significantly enhances the battery's lifespan.This study provides the first reported intrinsic understanding of the unique GBLgraphite incompatibility and offers valuable insights for the development of wide-temperature and high-safety LIBs.
基金supported in part by the National Natural Science Foundation of China under Grant 62062061/in part by the Major Project Cultivation Fund of Xizang Minzu University under Grant 324112300447.
文摘Recently,deep learning-based image inpainting methods have made great strides in reconstructing damaged regions.However,these methods often struggle to produce satisfactory results when dealing with missing images with large holes,leading to distortions in the structure and blurring of textures.To address these problems,we combine the advantages of transformers and convolutions to propose an image inpainting method that incorporates edge priors and attention mechanisms.The proposed method aims to improve the results of inpainting large holes in images by enhancing the accuracy of structure restoration and the ability to recover texture details.This method divides the inpainting task into two phases:edge prediction and image inpainting.Specifically,in the edge prediction phase,a transformer architecture is designed to combine axial attention with standard self-attention.This design enhances the extraction capability of global structural features and location awareness.It also balances the complexity of self-attention operations,resulting in accurate prediction of the edge structure in the defective region.In the image inpainting phase,a multi-scale fusion attention module is introduced.This module makes full use of multi-level distant features and enhances local pixel continuity,thereby significantly improving the quality of image inpainting.To evaluate the performance of our method.comparative experiments are conducted on several datasets,including CelebA,Places2,and Facade.Quantitative experiments show that our method outperforms the other mainstream methods.Specifically,it improves Peak Signal-to-Noise Ratio(PSNR)and Structure Similarity Index Measure(SSIM)by 1.141~3.234 db and 0.083~0.235,respectively.Moreover,it reduces Learning Perceptual Image Patch Similarity(LPIPS)and Mean Absolute Error(MAE)by 0.0347~0.1753 and 0.0104~0.0402,respectively.Qualitative experiments reveal that our method excels at reconstructing images with complete structural information and clear texture details.Furthermore,our model exhibits impressive performance in terms of the number of parameters,memory cost,and testing time.
基金the National Science Foundation of China for Distinguished Young Scholars(51925505)led by Yingguang Lifunding was obtained from the National Natural Science Foundation of China(52175467 and 51775278)led by Changqing Liu.
基金Supported by National Natural Science Foundation of China(Grant Nos.52005078,U1908231,52075076).
文摘The equipment used in various fields contains an increasing number of parts with curved surfaces of increasing size.Five-axis computer numerical control(CNC)milling is the main parts machining method,while dynamics analysis has always been a research hotspot.The cutting conditions determined by the cutter axis,tool path,and workpiece geometry are complex and changeable,which has made dynamics research a major challenge.For this reason,this paper introduces the innovative idea of applying dimension reduction and mapping to the five-axis machining of curved surfaces,and proposes an efficient dynamics analysis model.To simplify the research object,the cutter position points along the tool path were discretized into inclined plane five-axis machining.The cutter dip angle and feed deflection angle were used to define the spatial position relationship in five-axis machining.These were then taken as the new base variables to construct an abstract two-dimensional space and establish the mapping relationship between the cutter position point and space point sets to further simplify the dimensions of the research object.Based on the in-cut cutting edge solved by the space limitation method,the dynamics of the inclined plane five-axis machining unit were studied,and the results were uniformly stored in the abstract space to produce a database.Finally,the prediction of the milling force and vibration state along the tool path became a data extraction process that significantly improved efficiency.Two experiments were also conducted which proved the accuracy and efficiency of the proposed dynamics analysis model.This study has great potential for the online synchronization of intelligent machining of large surfaces.
基金supported by Xinjiang Medical University Education and Teaching Research Project“Virtual Simulation Technology Combined with PACS System in Medical Imaging Practice”(Project No.YG2021044).
文摘Objective:To explore the application effect of virtual simulation experiment combined with picture archiving and communication system(PACS)in medical imaging practical teaching.Methods:97 students from the medical imaging class of 2022 were divided into two groups;the control group(n=48)was taught by the traditional teaching method,whereas the research group was taught by virtual simulation experiment combined with PACS(n=49).The teaching achievements and teaching effects of the two groups were compared to define the advantages of the two teaching modes.Results:Initially,there were no significant differences in the basic theory,image analysis,report writing,and differential diagnosis scores between the two groups of students(P>0.05);however,after 16 weeks of teaching,the scores of the research group were better than those of the control group(P<0.05);the pass rate of students in the study group(93.88%)was higher than that in the control group(81.25%);the scores of students in the research group in terms of clinical inquiry skills,X-ray/computed tomography/magnetic resonance imaging(X-ray/CT/MRI)operation skills,and doctor-patient communication skills were significantly higher than those in the control group(P<0.05).Conclusion:In medical imaging practical teaching,the application of virtual simulation experiment combined with PACS can effectively address several problems in the traditional teaching mode,including the single teaching method,the single teaching content,and the lack of innovation,and,at the same time,improve students’basic theoretical knowledge,X-ray/CT/MRI operation skills,consultation skills,and doctor-patient communication skills,thereby effectively improving the teaching quality and learning effect.
文摘Fatigue has negative impacts on the general working population as well as on seafarers. In order to study seafarers’ fatigue, a questionnaire-base survey was conducted to gain information about potential risk factors for fatigue and construct indexes indicating fatigue. The study applies T-test to compare strata of seafarers to analyse work and sleep patterns in global seafaring. Qualitative analysis are also employed to explore the impacts of fatigue on seafarer’s occupational health and safety.
基金supported by the National Natural Science Foundation of China(51572253,21771171)Scientific Research Grant of Hefei National Synchrotron Radiation Laboratory(UN2017LHJJ)+1 种基金the Fundamental Research Funds for the Central Universitiescooperation between NSFC and Netherlands Organization for Scientific Research(51561135011)~~
文摘Photocatalytic H2 evolution reactions on pristine graphitic carbon nitrides(g-C3N4),as a promising approach for converting solar energy to fuel,are attractive for tackling global energy concerns but still suffer from low efficiencies.In this article,we report a tractable approach to modifying g-C3N4 with vanadyl phthalocyanine(VOPc/CN)for efficient visible-light-driven hydrogen production.A non-covalent VOPc/CN hybrid photocatalyst formed viaπ-πstacking interactions between the two components,as confirmed by analysis of UV-vis absorption spectra.The VOPc/CN hybrid photocatalyst shows excellent visible-light-driven photocatalytic performance and good stability.Under optimal conditions,the corresponding H2 evolution rate is nearly 6 times higher than that of pure g-C3N4.The role of VOPc in promoting hydrogen evolution activity was to extend the visible light absorption range and prevent the recombination of photoexcited electron-hole pairs effectively.It is expected that this facile modification method could be a new inspiration for the rational design and exploration of g-C3N4-based hybrid systems with strong light absorption and high-efficiency carrier separation.
基金Supported by National Natural Science Foundation of China(Grant Nos.U1709210,51505430)Key Research and Development Project of Zhejiang Province(Grant No.2019C03108)+1 种基金Public Project of Zhejiang Province(Grant No.LGG18E050021)Research Foundation from Zhejiang Sci-Tech University(Grant No.15022013-Y)
文摘The vibration propagates through the shaft in the form of elastic waves. The propagation characteristics of the elastic waves are a ected by the axial loads. The influence of the axial loads to the propagation characteristics of the elastic waves is studied in this paper. Firstly, the transfer matrix of the elastic waves for the non-uniform shaft with axial loads is deduced by combining the transfer matrix without axial load and the additional equation caused by the axial load. And then, a numerical method is used to study the influence of the axial load, non-uniformity and the rotating speed to the propagation characteristics of the elastic waves. It’s found that a new Stop Band will appear due to the axial force, and the central frequency of which will decrease as the increase of the force, while the band width of which remains the same. The central frequency of the new Stop Band will also increase as the increase of the cross-section area ratio;however, the rotating speed of the shaft doesn’t a ect the propagation characteristics of the elastic waves obviously. Finally, an experimental rig is built up for further study, even though there are some small local errors, the results of experiments match well with the numerical ones, which indicates the validation of the theoretical results. The result can help to study the influence of the axial load to the dynamics of a non-uniform shaft and help to reveal the vibration propagating mechanism in such a shaft.
基金National Natural Science Foundation of China(Grant No.51775278)National Science Fund of China for Distinguished Young Scholars(Grant No.51925505).
文摘Initial residual stress is the main reason causing machining deformation of the workpiece,which has been deemed as one of the most important aspects of machining quality issues.The inference of the distribution of initial residual stress inside the blank has significant meaning for machining deformation control.Due to the principle error of existing residual stress detection methods,there are still challenges in practical applications.Aiming at the detection problem of the initial residual stress field,an initial residual stress inference method by incorporating monitoring data and mechanism model is proposed in this paper.Monitoring data during machining process is used to represent the macroscopic characterization of the unbalanced residual stress,and the finite element numerical model is used as the mechanism model so as to solve the problem that the analytic mechanism model is difficult to establish;the policy gradient approach is introduced to solve the gradient descent problem of the combination of learning model and mechanism model.Finally,the initial residual stress field is obtained through iterative calculation based on the fusing method of monitoring data and mechanism model.Verification results show that the proposed inference method of initial residual stress field can accurately and effectively reflect the machining deformation in the actual machining process.
基金Sponsored by Major Science and Technology Program for Water Pollution Control and Treatment(Grant No.2012ZX07408001)State Key Laboratory of Urban Water Resource and Environment in China,Fundamental Research Funds for the Central Universities,China(Grant No.5710006113,HIT.BRETIII.201417)Postdoctoral Science Foundation of China(Grant No.2014T70324,LBH-Z12090)
文摘In order to investigate the effect of influent condition heterogeneity on diversity of the bacterial community,the degree of microbial resolution and effluent quality,biological treatment of micro-polluted source water is proposed. Scanning Electron Microscopy( SEM) analysis reflects that influent conditions change the morphologies of biofilm. Denaturing Gradient Gel Electrophoresis( DGGE) analysis shows differences of H values are due to succession of functional bacterial communities. Microbial resolution values and species identifications reveal organic carbon is the main cause of community differentiation and bacterial migration.
基金Project supported by the National Natural Science Foundation of China(Grant No.62275133)the Natural Science Foundation of Zhejiang Province of China(Grant No.LY22E020002)+1 种基金the Natural Science Foundation of Ningbo(Grant Nos.2021J077 and 202003N4099)K.C.Wong Magna Fund in Ningbo University
文摘By using an improved Bridgman method,0.3 mol%Tm^(3+)/0.6 mol%Tb^(3+)/y mol%Eu^(3+)(y=0,0.4,0.6,0.8)doped Na_(5)Y_(9)F_(32)single crystals were prepared.The x-ray diffraction,excitation spectra,emission spectra and fluorescence decay curves were used to explore the crystal structure and optical performance of the obtained samples.When excited by 362 nm light,the cool white emission was realized by Na_(5)Y_(9)F_(32)single crystal triply-doped with 0.3 mol%Tm^(3+)/0.6 mol%Tb^(3+)/0.8 mol%Eu^(3+),in which the Commission Internationale de l’Eclairage(CIE)chromaticity coordinate was(0.2995,0.3298)and the correlated color temperature(CCT)was 6586 K.The integrated normalized emission intensity of the tridoped single crystal at 448 K could keep 62%of that at 298 K.The internal quantum yield(QY)was calculated to be~15.16%by integrating spheres.These results suggested that the single crystals tri-doped with Tm^(3+),Tb^(3+)and Eu^(3+)ions have a promising potential application for white light-emitting diodes(w-LEDs).
基金This work is supported by National Key R&D Programs of China,No.2021YFB3301302the National Natural Science Foundation of China,No.52175467the National Science Fund of China for Distinguished Young Scholars,No.51925505。
文摘Precise control of machining deformation is crucial for improving the manufacturing quality of structural aerospace components.In the machining process,different batches of blanks have different residual stress distributions,which pose a significant challenge to machining deformation control.In this study,a reinforcement learning method for machining deformation control based on a meta-invariant feature space was developed.The proposed method uses a reinforcement-learning model to dynamically control the machining process by monitoring the deformation force.Moreover,combined with a meta-invariant feature space,the proposed method learns the internal relationship of the deformation control approaches under different stress distributions to achieve the machining deformation control of different batches of blanks.Finally,the experimental results show that the proposed method achieves better deformation control than the two existing benchmarking methods.
文摘The purpose of this paper is to study the air pollutants in Xiong’an New Area based on MATLAB grey model [1]. From 2011 to 2016, the results of sulfur dioxide (SO2), nitrogen dioxide (NO2) and inhalable particulate matter (PM1O) detected at monitoring points in the three counties of Xiong’an were analyzed. According to the national environmental air quality standard [2], the air quality in Xiong’an New Area was reasonably evaluated based on grey model in MATLAB. Judging from the weight of pollution factors in the model, sulfur dioxide (SO2) is the controlling factor of air quality in Xiong’an New Area, and the weight of nitrogen dioxide (NO2) gradually increases. The main sources of the three pollutants were obtained by comprehensive data analysis, and a grey model was established according to the mass concentration of the main air pollutants, and the grey forecasting model was tested. The experimental results show that the model can be effectively applied to the forecasting of ambient air quality. On this basis, the present situation of atmospheric environmental quality in Xiong’an New Area and suggestions for improvement are obtained.
基金supported by the National Natural Science Foundation of China(No.52274362)the Doctorial Foundation of Henan University of Technology(Nos.2021BS030 and 2020BS030)+5 种基金the Key R&D projects of Henan Province(No.221111230800)the Innovative Funds Plan of Henan University of Technology(No.2021ZKCJ05)the Key Scientific and Technological Research Projects in Henan Province(No.222102240091)the Natural Science Foundation from the Department of Science and Technology of Henan Province(No.232300420309)the Taishan Scholars and Young Experts Program of Shandong Province(No.tsqn202103057)the Key Laboratory of Engineering Dielectrics and Its Application(Harbin University of Science and Technology),Ministry of Education.
文摘The accelerated arriving of 5G era has brought a new round of intelligent transformation which will completely emancipate smart terminal devices.While the subsequent deleterious effect of electromagnetic wave on electronic devices is increasingly serious,driving the growth of next-generation electromagnetic wave absorbents.As a tactful combination of components and structures,three-dimensional(3D)macroscopic absorbents with fascinating synergy afford exceptional electromagnetic wave absorption,and tremendous efforts have been devoted to this investigation.However,in terms of macroscopic absorbents and their synergistic effect,few reviews are proposed to comb the latest achievements and detailed synergy.This review article focuses on the synergistic effect of macro-architectured absorbents mainly including structure-induced synergy,structure-components synergy,and multiple-components induced synergy.And then the potential construction principles and strategies of macroscopic absorbents are combed.Significantly,the key information for structures and components manipulation including nano-micro design and components regulation is further dissected by critically selected cutting-edge 3D macroscopic absorbents.Moreover,a brief summary of multifunctional electromagnetic wave absorbents(EWAs)-based macroscopic structures is presented.Finally,the development prospects and challenges of these materials are discussed.
基金supported by the National Key Research and Development Program of China(No.2022YFE0139100)International cooperative research project of Jiangsu province(No.BZ2022008)+3 种基金the Natural Science Foundation Project of China(No.62175028)the Program 111_2.0 in China(No.BP0719013)Leading Technology of Jiangsu Basic Research Plan(No.BK20192003)Postgraduate Research&Practice Innovation Program of Jiangsu Province,and the Fundamental Research Funds for the Central Universities(No.KYCX23_0254).
文摘As an emerging information device that adapts to development of the big data era,memristor has attracted much attention due to its advantage in processing massive data.However,the nucleation and growth of conductive filaments often exhibit randomness and instability,which undoubtedly leads to a wide and discrete range of switching parameters,damaging the electrical performance of device.In this work,a strategy of inserting carbon quantum dots(CQDs)into graphene oxide(GO)resistance layer is utilized to improve the stability of the switching parameters and the reliability of the device is improved.Compared with GO-based devices,GO/CQDs/GO-based devices exhibit a more stable resistance switching curve,low power,lower and more concentrated threshold voltage parameters with lower variation coefficient,faster switching speed,and more stable retention and endurance.The cause-inducing performance improvement may be attributed to the local electric field generated by CQDs in resistance switching that effectively guides the formation and rupture of conductive filaments,which optimizes the effective migration distance of Ag^(+),thereby improving the uniformity of resistance switching.Additionally,a convolutional neural network model is constructed to identify the CIFAR-10 data set,showing the high recognition accuracy of online and offline learning.The cross-kernel structure is used to further implement convolutional image processing through multiplication and accumulation operations.This work provides a solution to improve the performance of memristors,which can contribute to developing digital information processing.