Bulking characteristics of gangue are of great significance for the stability of goafs in mining overburden in the caving zones.In this paper,a particle discrete element method with clusters to represent gangue was ad...Bulking characteristics of gangue are of great significance for the stability of goafs in mining overburden in the caving zones.In this paper,a particle discrete element method with clusters to represent gangue was adopted to explore the bulking coefficient time effect of the broken rock in the caving zone under three-dimensional triaxial compression condition.The phenomena of stress corrosion,deformation,and failure of rock blocks were simulated in the numerical model.Meanwhile,a new criterion of rock fragments damage was put forward.It was found that the broken rock has obvious viscoelastic properties.A new equation based on the Burgers creep model was proposed to predict the bulking coefficient of broken rock.A deformation characteristic parameter of the prediction equation was analyzed,which can be set as a fixed value in the mid-and long-term prediction of the bulking coefficient.There are quadratic function relationships between the deformation characteristic parameter value and Talbot gradation index,axial pressure and confining pressure.展开更多
Underground mining is an economically viable option for exploiting ore reserves deemed uneconomic after open pit mining. However, underground development can have adverse effects on the above existing open pit slope w...Underground mining is an economically viable option for exploiting ore reserves deemed uneconomic after open pit mining. However, underground development can have adverse effects on the above existing open pit slope walls. As a goal of this paper, identification and assessment of potential slope instabilities prior to underground development is crucial for safe and sustainable mining. Towards goal achieving, this paper gives a comprehensive parametric study to investigate the influence of sublevel open stope (SLOS) underground mining on the surface and open pit slope walls. By means of numerical simulation, the SLOS design is tried against the existing open pit followed by adjustments of important slope parameters which are overall slope height (OSH) and overall slope angle (OSA). We found that underground mining may induce slope failure, particularly on the hangingwall side of the pit. Subsidence is prominent on the hanging wall and the surface, whereas, the uplift dominates the footwall and pit bottom. Pit wall closure is observed during underground mining. Although the assigned dimensions in the parametric study show a negligible effect of OSH and OSA, the high OSH experience low subsidence in comparison with low OSH. Overall, the results demonstrate that the slope walls on the hanging wall side are mostly affected by the underground mining and high-stress concentration prevails near slope toes and pit bottom. Additionally, slope deformation decrease from pit bottom towards the slope crest and surface. The results of this study add knowledge to open pit and underground mining interaction.展开更多
[Objectives] The research aimed to study the effect of sludge extract on the growth of Zinnia elegans, and evaluate its possibility of application. [Methods] Z. elegans was taken as research object, and the effect of ...[Objectives] The research aimed to study the effect of sludge extract on the growth of Zinnia elegans, and evaluate its possibility of application. [Methods] Z. elegans was taken as research object, and the effect of sludge extract on the growth indicators of Z. elegans was studied. [Results] The sludge extract can obviously promote the growth of Z. elegans, and the growth indicators were significantly improved when compared with the control group. The application effect was close to that of foliar fertilizer purchased in the market. In each treatment group, the low concentration of sludge extract did not significantly promote the growth of Z. elegans, while too high concentration could inhibit its growth, and the optimal dilution ratio was 600 times. [Conclusions] Further preparation of amino acid foliar fertilizer from sludge extract and its application in planting garden plants can realize the resource utilization of sludge and has a good development and application prospect.展开更多
Lipid nanoparticles(LNPs)have emerged as versatile and widely utilized delivery systems in both academic research and industrial applications,offering immense potential beyond liver-targeted and infectious disease tre...Lipid nanoparticles(LNPs)have emerged as versatile and widely utilized delivery systems in both academic research and industrial applications,offering immense potential beyond liver-targeted and infectious disease treatments.Despite their success,a significant limitation of LNPs is their inherent liver tropism following systemic administration.This liver-centric accumulation represents a key bottleneck,restricting the broader therapeutic applications of LNP-based delivery systems.In this review,we explore strategies to overcome this challenge by modulating LNP composition-including ionizable lipids,helper lipids,cholesterol,and other critical components-to achieve extrahepatic targeting.We further discuss recent advancements in surface modification techniques designed to redirect LNPs to organs beyond the liver.Additionally,we highlight recent progress in local delivery approaches,which offer a direct and effective alternative for achieving extrahepatic delivery.By providing a comprehensive overview of current strategies and limitations,we aim to guide future research efforts toward fully realizing the therapeutic potential of LNP-based delivery systems.展开更多
This study shows that convolutional neural networks(CNNs)can be used to improve the performance of structured illumination microscopy to enable it to reconstruct a super-resolution image using three instead of nine ra...This study shows that convolutional neural networks(CNNs)can be used to improve the performance of structured illumination microscopy to enable it to reconstruct a super-resolution image using three instead of nine raw frames,which is the standard number of frames required to this end.Owing to the isotropy of the fluorescence group,the correlation between the high-frequency information in each direction of the spectrum is obtained by training the CNNs.A high-precision super-resolution image can thus be reconstructed using accurate data from three image frames in one direction.This allows for gentler super-resolution imaging at higher speeds and weakens phototoxicity in the imaging process.展开更多
Background:Emerging mite-borne pathogens and associated disease burdens in recent decades are raising serious public health concerns,yet their distributions and ecology remain under-investigated.We aim to describe the...Background:Emerging mite-borne pathogens and associated disease burdens in recent decades are raising serious public health concerns,yet their distributions and ecology remain under-investigated.We aim to describe the geographical distributions of blood-sucking mites and mite-borne agents and to assess their ecological niches in China.Methods:We mapped 549 species of blood-sucking mites belonging to 100 genera at the county level and eight mite-associated agents detected from 36 species of blood-sucking mites in China during 1978–2020.Impacts of climatic and environmental factors on the ecology of 21 predominant vector mites and a leading pathogen,Orientia tsutsugamushi,were assessed using boosted regression tree(BRT)models,and model-predicted risks were mapped.We also estimated the model-predicted number,area and population size of afected counties for each of the 21 mite species in China.Results:Laelaps echidninus is the leading mite species that potentially afects 744 million people,followed by La.jettmari(517 million)and Eulaelaps stabularis(452 million).Leptotrombidium scutellare is the mite species harboring the highest variety of mite-borne agents including four Rickettsia species and two viruses,followed by Eu.stabularis(2 agents),L.palpale(2)and La.echidninus(2).The top two agents that parasitize the largest number of mite species are O.tsutsugamushi(28 species)and hantavirus(8).Mammalian richness,annual mean temperature and precipitation of the driest quarter jointly determine the ecology of the mites,forming four clusters of major mite species with distinct geographic distributions.High-risk areas of O.tsutsugamushi are mainly distributed in southern and eastern coastal provinces where 71.5 million people live.Conclusions:Ecological niches of major mite species and mite-borne pathogens are much more extensive than what have been observed,necessitating expansion of current fled surveillance.展开更多
Topological spin structures of light,including the Skyrmion,Meron,and bi-Meron,are intriguing optical phenomena that arise from spin-orbit coupling.They have promising potential applications in nano-metrology,data sto...Topological spin structures of light,including the Skyrmion,Meron,and bi-Meron,are intriguing optical phenomena that arise from spin-orbit coupling.They have promising potential applications in nano-metrology,data storage,super-resolved imaging and chiral detection.Aside from the electric part of optical spin,of equal importance is the magnetic part,particularly the H-type electromagnetic modes for which the spin topological properties of the field are dominated by the magnetic field.However,their observation and measurement remains absent and faces difficult challenges.Here,we design a unique type of anapole probe to measure specifically the photonic spin structures dominated by magnetic fields.The probe is composed of an Ag-core and Si-shell nanosphere,which manifests as a pure magnetic dipole with no electric response.The effectiveness of the method was validated by characterizing the magnetic field distributions of various focused vector beams.It was subsequently employed to measure the magnetic topological spin structures,including individual Skyrmions and Meron/Skyrmion lattices for the first time.The proposed method may be a powerful tool to characterize the magnetic properties of optical spin and valuable in advancing spin photonics.展开更多
Discontinuities or structural planes are widely distributed in natural rock masses and significantly influence their geo-mechanical and geometric properties.Herein,a batch of rock samples,each with a single structural...Discontinuities or structural planes are widely distributed in natural rock masses and significantly influence their geo-mechanical and geometric properties.Herein,a batch of rock samples,each with a single structural plane,is created using a 3D printer equipped with two robotic manipulators.One of the manipulators is connected via a nozzle to a concrete pumping truck,which can extrude brittle rock-like material to form layered intact rock masses;the rock-like material is mainly composed of cement,silica fume,sand and water.The other manipulator features a knife,which can carve discontinuities onto each layer of the printed model.By means of this system,rock masses with discontinuous joints are formed,and the failure strengths of rock masses with different joints are demonstrated via uniaxial compression tests and direct shear tests.The results thereof obtained via digital image correlation technology show that discontinuities lower the strength of the rock mass models significantly.With the increase of the angle between the fracture and horizontal plane,the uniaxial compressive strength first decreases,and then increases.During shear testing,the shear strength of the rock mass models increases with the surface roughness of the preset joint.These test results indicate that the influence of artificial joints on the mechanical properties of the models is consistent with that of natural rock mass joints.Using digital modeling and 3D printing technology,cracks hidden in a rock mass can be reproduced.展开更多
Spectrum sensing technology is a crucial aspect of modern communication technology,serving as one of the essential techniques for efficiently utilizing scarce information resources in tight frequency bands.This paper ...Spectrum sensing technology is a crucial aspect of modern communication technology,serving as one of the essential techniques for efficiently utilizing scarce information resources in tight frequency bands.This paper first introduces three common logical circuit decision criteria in hard decisions and analyzes their decision rigor.Building upon hard decisions,the paper further introduces a method for multi-user spectrum sensing based on soft decisions.Then the paper simulates the false alarm probability and detection probability curves corresponding to the three criteria.The simulated results of multi-user collaborative sensing indicate that the simulation process significantly reduces false alarm probability and enhances detection probability.This approach effectively detects spectrum resources unoccupied during idle periods,leveraging the concept of time-division multiplexing and rationalizing the redistribution of information resources.The entire computation process relies on the calculation principles of power spectral density in communication theory,involving threshold decision detection for noise power and the sum of noise and signal power.It provides a secondary decision detection,reflecting the perceptual decision performance of logical detection methods with relative accuracy.展开更多
基金This work was supported by the National Natural Science Foundation of China,NSFC(Nos.U1803118 and 51974296)and the China Scholarship Council(CSC)(award to Fanfei Meng for PhD period at Kyushu University).
文摘Bulking characteristics of gangue are of great significance for the stability of goafs in mining overburden in the caving zones.In this paper,a particle discrete element method with clusters to represent gangue was adopted to explore the bulking coefficient time effect of the broken rock in the caving zone under three-dimensional triaxial compression condition.The phenomena of stress corrosion,deformation,and failure of rock blocks were simulated in the numerical model.Meanwhile,a new criterion of rock fragments damage was put forward.It was found that the broken rock has obvious viscoelastic properties.A new equation based on the Burgers creep model was proposed to predict the bulking coefficient of broken rock.A deformation characteristic parameter of the prediction equation was analyzed,which can be set as a fixed value in the mid-and long-term prediction of the bulking coefficient.There are quadratic function relationships between the deformation characteristic parameter value and Talbot gradation index,axial pressure and confining pressure.
文摘Underground mining is an economically viable option for exploiting ore reserves deemed uneconomic after open pit mining. However, underground development can have adverse effects on the above existing open pit slope walls. As a goal of this paper, identification and assessment of potential slope instabilities prior to underground development is crucial for safe and sustainable mining. Towards goal achieving, this paper gives a comprehensive parametric study to investigate the influence of sublevel open stope (SLOS) underground mining on the surface and open pit slope walls. By means of numerical simulation, the SLOS design is tried against the existing open pit followed by adjustments of important slope parameters which are overall slope height (OSH) and overall slope angle (OSA). We found that underground mining may induce slope failure, particularly on the hangingwall side of the pit. Subsidence is prominent on the hanging wall and the surface, whereas, the uplift dominates the footwall and pit bottom. Pit wall closure is observed during underground mining. Although the assigned dimensions in the parametric study show a negligible effect of OSH and OSA, the high OSH experience low subsidence in comparison with low OSH. Overall, the results demonstrate that the slope walls on the hanging wall side are mostly affected by the underground mining and high-stress concentration prevails near slope toes and pit bottom. Additionally, slope deformation decrease from pit bottom towards the slope crest and surface. The results of this study add knowledge to open pit and underground mining interaction.
基金Supported by Science and Technology Top Talent Support Project of Guizhou Provincial Department of Education (QIANJIAOHE KY ZI[2018]044)Innovation and Entrepreneurship Training Program for College Students(201510672007,201710672011)。
文摘[Objectives] The research aimed to study the effect of sludge extract on the growth of Zinnia elegans, and evaluate its possibility of application. [Methods] Z. elegans was taken as research object, and the effect of sludge extract on the growth indicators of Z. elegans was studied. [Results] The sludge extract can obviously promote the growth of Z. elegans, and the growth indicators were significantly improved when compared with the control group. The application effect was close to that of foliar fertilizer purchased in the market. In each treatment group, the low concentration of sludge extract did not significantly promote the growth of Z. elegans, while too high concentration could inhibit its growth, and the optimal dilution ratio was 600 times. [Conclusions] Further preparation of amino acid foliar fertilizer from sludge extract and its application in planting garden plants can realize the resource utilization of sludge and has a good development and application prospect.
基金supported by the start-up package from the University of Massachusetts Lowell.
文摘Lipid nanoparticles(LNPs)have emerged as versatile and widely utilized delivery systems in both academic research and industrial applications,offering immense potential beyond liver-targeted and infectious disease treatments.Despite their success,a significant limitation of LNPs is their inherent liver tropism following systemic administration.This liver-centric accumulation represents a key bottleneck,restricting the broader therapeutic applications of LNP-based delivery systems.In this review,we explore strategies to overcome this challenge by modulating LNP composition-including ionizable lipids,helper lipids,cholesterol,and other critical components-to achieve extrahepatic targeting.We further discuss recent advancements in surface modification techniques designed to redirect LNPs to organs beyond the liver.Additionally,we highlight recent progress in local delivery approaches,which offer a direct and effective alternative for achieving extrahepatic delivery.By providing a comprehensive overview of current strategies and limitations,we aim to guide future research efforts toward fully realizing the therapeutic potential of LNP-based delivery systems.
基金Science and Technology Innovation Commission of Shenzhen(KQTD2015071016560101,KQTD2017033011044403,ZDSYS201703031605029)Natural Science Foundation of Guangdong Province(2016A030312010)+2 种基金Leading Talents Program of Guangdong Province(00201505)National Natural Science Foundation of China(61490712,61622504,61775085,91850202)China Postdoctoral Science Foundation(2019M663048).
文摘This study shows that convolutional neural networks(CNNs)can be used to improve the performance of structured illumination microscopy to enable it to reconstruct a super-resolution image using three instead of nine raw frames,which is the standard number of frames required to this end.Owing to the isotropy of the fluorescence group,the correlation between the high-frequency information in each direction of the spectrum is obtained by training the CNNs.A high-precision super-resolution image can thus be reconstructed using accurate data from three image frames in one direction.This allows for gentler super-resolution imaging at higher speeds and weakens phototoxicity in the imaging process.
文摘Background:Emerging mite-borne pathogens and associated disease burdens in recent decades are raising serious public health concerns,yet their distributions and ecology remain under-investigated.We aim to describe the geographical distributions of blood-sucking mites and mite-borne agents and to assess their ecological niches in China.Methods:We mapped 549 species of blood-sucking mites belonging to 100 genera at the county level and eight mite-associated agents detected from 36 species of blood-sucking mites in China during 1978–2020.Impacts of climatic and environmental factors on the ecology of 21 predominant vector mites and a leading pathogen,Orientia tsutsugamushi,were assessed using boosted regression tree(BRT)models,and model-predicted risks were mapped.We also estimated the model-predicted number,area and population size of afected counties for each of the 21 mite species in China.Results:Laelaps echidninus is the leading mite species that potentially afects 744 million people,followed by La.jettmari(517 million)and Eulaelaps stabularis(452 million).Leptotrombidium scutellare is the mite species harboring the highest variety of mite-borne agents including four Rickettsia species and two viruses,followed by Eu.stabularis(2 agents),L.palpale(2)and La.echidninus(2).The top two agents that parasitize the largest number of mite species are O.tsutsugamushi(28 species)and hantavirus(8).Mammalian richness,annual mean temperature and precipitation of the driest quarter jointly determine the ecology of the mites,forming four clusters of major mite species with distinct geographic distributions.High-risk areas of O.tsutsugamushi are mainly distributed in southern and eastern coastal provinces where 71.5 million people live.Conclusions:Ecological niches of major mite species and mite-borne pathogens are much more extensive than what have been observed,necessitating expansion of current fled surveillance.
基金This work was supported by the Guangdong Major Project of Basic Research No.2020B0301030009the National Natural Science Foundation of China Grants U1701661,61935013,62075139,61905163,62205217,12174266,12174310,and 12204309+4 种基金the Leadership of Guangdong Province Program Grant 00201505Natural Science Foundation of Guangdong Province Grant 2016A030312010Science and Technology Innovation Commission of Shenzhen Grants RCJC20200714114435063 and JCYJ20200109114018750Shenzhen Peacock Plan Grants KQTD2015071016560101 and KQTD20170330110444030China Postdoctoral Science Foundation(Grant No.2019M663048).
文摘Topological spin structures of light,including the Skyrmion,Meron,and bi-Meron,are intriguing optical phenomena that arise from spin-orbit coupling.They have promising potential applications in nano-metrology,data storage,super-resolved imaging and chiral detection.Aside from the electric part of optical spin,of equal importance is the magnetic part,particularly the H-type electromagnetic modes for which the spin topological properties of the field are dominated by the magnetic field.However,their observation and measurement remains absent and faces difficult challenges.Here,we design a unique type of anapole probe to measure specifically the photonic spin structures dominated by magnetic fields.The probe is composed of an Ag-core and Si-shell nanosphere,which manifests as a pure magnetic dipole with no electric response.The effectiveness of the method was validated by characterizing the magnetic field distributions of various focused vector beams.It was subsequently employed to measure the magnetic topological spin structures,including individual Skyrmions and Meron/Skyrmion lattices for the first time.The proposed method may be a powerful tool to characterize the magnetic properties of optical spin and valuable in advancing spin photonics.
基金the National Natural Science Foundation of China(Grant No.51627812,No.51878241 and No.U1965204).
文摘Discontinuities or structural planes are widely distributed in natural rock masses and significantly influence their geo-mechanical and geometric properties.Herein,a batch of rock samples,each with a single structural plane,is created using a 3D printer equipped with two robotic manipulators.One of the manipulators is connected via a nozzle to a concrete pumping truck,which can extrude brittle rock-like material to form layered intact rock masses;the rock-like material is mainly composed of cement,silica fume,sand and water.The other manipulator features a knife,which can carve discontinuities onto each layer of the printed model.By means of this system,rock masses with discontinuous joints are formed,and the failure strengths of rock masses with different joints are demonstrated via uniaxial compression tests and direct shear tests.The results thereof obtained via digital image correlation technology show that discontinuities lower the strength of the rock mass models significantly.With the increase of the angle between the fracture and horizontal plane,the uniaxial compressive strength first decreases,and then increases.During shear testing,the shear strength of the rock mass models increases with the surface roughness of the preset joint.These test results indicate that the influence of artificial joints on the mechanical properties of the models is consistent with that of natural rock mass joints.Using digital modeling and 3D printing technology,cracks hidden in a rock mass can be reproduced.
文摘Spectrum sensing technology is a crucial aspect of modern communication technology,serving as one of the essential techniques for efficiently utilizing scarce information resources in tight frequency bands.This paper first introduces three common logical circuit decision criteria in hard decisions and analyzes their decision rigor.Building upon hard decisions,the paper further introduces a method for multi-user spectrum sensing based on soft decisions.Then the paper simulates the false alarm probability and detection probability curves corresponding to the three criteria.The simulated results of multi-user collaborative sensing indicate that the simulation process significantly reduces false alarm probability and enhances detection probability.This approach effectively detects spectrum resources unoccupied during idle periods,leveraging the concept of time-division multiplexing and rationalizing the redistribution of information resources.The entire computation process relies on the calculation principles of power spectral density in communication theory,involving threshold decision detection for noise power and the sum of noise and signal power.It provides a secondary decision detection,reflecting the perceptual decision performance of logical detection methods with relative accuracy.
