As a new technical means that can detect abnormal signs of water inrush in advance and give an early warning,the automatic monitoring and early warning of water inrush in mines has been widely valued in recent years.D...As a new technical means that can detect abnormal signs of water inrush in advance and give an early warning,the automatic monitoring and early warning of water inrush in mines has been widely valued in recent years.Due to the many factors affecting water inrush and the complicated water inrush mechanism,many factors close to water inrush may have precursory abnormal changes.At present,the existing monitoring and early warning system mainly uses a few monitoring indicators such as groundwater level,water influx,and temperature,and performs water inrush early warning through the abnormal change of a single factor.However,there are relatively few multi-factor comprehensive early warning identification models.Based on the analysis of the abnormal changes of precursor factors in multiple water inrush cases,11 measurable and effective indicators including groundwater flow field,hydrochemical field and temperature field are proposed.Finally,taking Hengyuan coal mine as an example,6 indicators with long-term monitoring data sequences were selected to establish a single-index hierarchical early-warning recognition model,a multi-factor linear recognition model,and a comprehensive intelligent early-warning recognition model.The results show that the correct rate of early warning can reach 95.2%.展开更多
Flow of fluids within biological tissues often meets with resistance that causes a rate-and size-dependent material behavior known as poroelasticity.Characterizing poroelasticity can provide insight into a broad range...Flow of fluids within biological tissues often meets with resistance that causes a rate-and size-dependent material behavior known as poroelasticity.Characterizing poroelasticity can provide insight into a broad range of physiological functions,and is done qualitatively in the clinic by palpation.Indentation has been widely used for characterizing poroelasticity of soft materials,where quantitative interpretation of indentation requires a model of the underlying physics,and such existingmodels are well established for cases of small strain and modest force relaxationWe showed here that existing models are inadequate for large relaxation,where the force on the indenter at a prescribed depth at long-time scale drops to below half of the initially peak force.We developed an indentation theory for such cases of large relaxation,based upon Biot theory and a generalized Hertz contact model.We demonstrated that proposed theory is suitable for biological tissues(e.g.,spleen,kidney,skin and human cirrhosis liver)with both small and large relaxations.The proposed method would be a powerful tool to characterize poroelastic properties of biological materials for various applications such as pathological study and disease diagnosis.展开更多
Objective: This study is designed to observe the chronic toxicity after the administration of mulberry sea-buckthorn beverage concentrate for 3 months on rats and to predict the possible adverse effect and the potenti...Objective: This study is designed to observe the chronic toxicity after the administration of mulberry sea-buckthorn beverage concentrate for 3 months on rats and to predict the possible adverse effect and the potential toxicity target organs. Method: The rats (SPF level) were randomly divided into high-dose (20 mL/kg BW), middle-dose (10 mL/kg BW), low-dose (5 mL/kg BW) groups and negative control group (20 mL/kg BW of purified water) with 30 rats in each group. Each group was orally given mulberry sea-buckthorn beverage concentrate for 3 months and recovered by stop feeding samples for 2 weeks for a recovery observation. The rats’ general condition, the organ coefficient, the indexes of hematology and blood biochemistry and the histological changes of the main organs were determined. Result: The appearance and behavior of activity in rats showed no anomalies in all these groups and all the rats put on weight during this period. Comparing to the negative control group, no obvious differences were observed in the weekly weight and organ coefficient of each dose group. After 3 months of administration, HGB in both mulberry sea-buckthorn beverage concentrate low-dose group and high-dose group were increased. No significant differences were observed in the indexes of hematology after 2 weeks of recovery. CREA in low-dose, middle-dose and high-dose groups were significantly increased after 3 months of administration and it remained in the high level in middle-dose and high-dose group even after 2 weeks of recovery. No drug-related lesions were observed in the histological changes of major organs. Conclusion: The results show that long term use of mulberry concentrated sea-buckthorn beverage can lead to increased CREA, which suggested kidney toxicity. Although no obvious pathological change was found in kidney, we should pay attention to chronic kidney damage in the further research.展开更多
For the sake of mine water drainage and sustainable groundwater protection,the new approach of mine water deep geological storage(MWDGS)is highly necessary to save water resources in the semi-arid region of China.Howe...For the sake of mine water drainage and sustainable groundwater protection,the new approach of mine water deep geological storage(MWDGS)is highly necessary to save water resources in the semi-arid region of China.However,up to now,little academic research has been done on mine water geological storage.Given this situation,the hydrogeological feasibility of MWDGS was explored in Baotashan coarse sandstone(BCS)of Jurassic measure in Ordos Basin.The results show that the white-gray BCS with a fragile skeleton of quartz(41.4%),feldspar(21.1%),and clay minerals(16.4%)provides the potential variable-void for mine water;and its hydro-chemical type of BCS aquifer is CO_(3)-Na and Cl-Na.As the burial depth increases,the strong alkaline groundwater is in stagnant and poor recharge-runoff-discharge condition.The lab test shows that the pores whose diameter is over 10μm could be treated as the main storage of mine water;and the effective porosity varies from 1.36%to 3.46%.When mine water is injected,the strong hydrodynamics of mine water storage would change the permeability significantly and about 0.201%soluble solids would be dissolved.Partial clay minerals obstruct the pores and induce the saturated phase of high permeability to evolve into steady phase of lower permeability.Under the condition of nonhydraulic fracturing during continuous storage,the heterogeneous anisotropic medium obtained by Transition PRObability GeoStatistics(TPROGS)shows that the capacity of BCS aquifer is 0.455 to 1.226Mm^(3)for 1 km^(2)in the study area.The simulation shows that the groundwater mound in well-scale and mine-scale would be formed.The groundwater quality characteristics of“Three Zone”would occur around and gradually drop to approximate the original brine within 10 years.The hydrogeological feasibility reveals that this approach is useful for the well design and groundwater environment management during the mine water deep geological storage project in the Ordos basin.展开更多
PbTiO_(3)-based piezoelectric ceramics are key materials for developing various electromechanical transduc-ers.For high-power ultrasonic transducers,piezoelectric ceramics are required to possess large piezo-electric ...PbTiO_(3)-based piezoelectric ceramics are key materials for developing various electromechanical transduc-ers.For high-power ultrasonic transducers,piezoelectric ceramics are required to possess large piezo-electric coefficient(d_(33))and high mechanical quality factor(Q_(m)).Although acceptor dopants can im-prove Q_(m),they also deteriorate d_(33).If suitable piezoelectricity-beneficial donor dopants can be intro-duced into acceptor-doped ceramics,it is very possible to obtain large d_(33)and high Q_(m)simultaneously in donor and acceptor co-doped ceramics.In this work,a series of x mol%Sm and y mol%Mn co-doped Pb(Mg_(1/3)Nb_(2/3))O_(3)-30PbTiO_(3)(PMN-30PT:x Sm,y Mn)ceramics were prepared by the solid-phase sintered method.The crystal structure,local domain structure and electromechanical properties were sys-tematically analyzed.Optimal performances were obtained in PMN-30PT:2.5Sm,1-2Mn ceramics with d_(33)=860-543 pC/N,Q_(m)=495-754,and dielectric loss tanδ=0.0055-0.0086.This high performance origi-nates from the combined effects of(Mn″Ti−V_(o)^(••))^(×)defect dipoles and the local structural heterogeneity.展开更多
Digital holography records the entire wavefront of an object,including amplitude and phase.To reconstruct the object numerically,we can backpropagate the hologram with Fresnel–Kirchhoff integralbased algorithms such ...Digital holography records the entire wavefront of an object,including amplitude and phase.To reconstruct the object numerically,we can backpropagate the hologram with Fresnel–Kirchhoff integralbased algorithms such as the angular spectrum method and the convolution method.Although effective,these techniques require prior knowledge,such as the object distance,the incident angle between the two beams,and the source wavelength.Undesirable zero-order and twin images have to be removed by an additional filtering operation,which is usually manual and consumes more time in off-axis configuration.In addition,for phase imaging,the phase aberration has to be compensated,and subsequently an unwrapping step is needed to recover the true object thickness.The former either requires additional hardware or strong assumptions,whereas the phase unwrapping algorithms are often sensitive to noise and distortion.Furthermore,for a multisectional object,an all-in-focus image and depth map are desired for many applications,but current approaches tend to be computationally demanding.We propose an end-to-end deep learning framework,called a holographic reconstruction network,to tackle these holographic reconstruction problems.Through this data-driven approach,we show that it is possible to reconstruct a noise-free image that does not require any prior knowledge and can handle phase imaging as well as depth map generation.展开更多
Gibberellic acid(GA_(3))is widely used in agriculture and maybe transfer with groundwater flow,which is an endocrine disruptor,but few studies have focused on the transformation pathway and toxicity assessment of GA_(...Gibberellic acid(GA_(3))is widely used in agriculture and maybe transfer with groundwater flow,which is an endocrine disruptor,but few studies have focused on the transformation pathway and toxicity assessment of GA_(3)and its products.Here,GA_(3)and its transformation products in aqueous solution were identified and quantified by liquid chromatography mass spectrometry hybrid ion trap time-of-flight(LCMS-IT-TOF)and high-performance liquid chromatography(HPLC),respectively.The results showed that the half-life of GA_(3)transformation in ultrapure water was 16.1–24.6 days at p H=2.0–8.0,with the lowest half-life occurring at p H=8.0 and highest half-life occurring at p H=3.3.Isomerized gibberellic acid(Iso-GA_(3))and gibberellenic acid(GEA)were the main transformation products with a little hydroxy gibberellic acid(OH-GA_(3)).In North China groundwater,the mass balance of GA_(3)and its products was 76.2%,including Iso-GA_(3)(58%),GEA(7.9%),GA_(3)(7.3%)and OH-GA_(3)(3%)after reaching transformation equilibrium.Using Gaussian 09 for chemical computation,it was found that the transformation mechanism of GA_(3)was dependent upon the bond energy and the stereochemical feature of its molecular structure.GA_(3)always isomerized from theγ-lactone ring due to the lowest bond energy between the oxygen terminus of theγ-lactone ring and A ring.While GA_(3)and its transformation products all had developmental toxicity,the predicated LC 50(96 hr)and LD 50 of the main products of GA_(3)were much lower than those of GA_(3),indicating GA_(3)would be transformed into higher toxicity derivatives in water environments,posing a significant health risk to humans and the environment.展开更多
Topography of acoustic response characteristics in the auditory cortex (AC) of the Kunming (KM) mouse has been examined by using microelectrode recording techniques. Based on best-frequency (BF) maps, both the primary...Topography of acoustic response characteristics in the auditory cortex (AC) of the Kunming (KM) mouse has been examined by using microelectrode recording techniques. Based on best-frequency (BF) maps, both the primary auditory field (Al) and the anterior auditory field (AAF) are tonotopically organized with a counter running frequency gradient. within an isofrequency stripe, the width of the frequency-threshold curves of single neurons increases, and minimum threshold (MT) decreases towards more ventral locations. BFs in Al and AAF range from 4 to 38 kHz. Auditory neurons with BFs above 40 kHz are located at the rostrodorsal part of the AC. The findings suggest that the KM mouse is a good model suitable for auditory research.展开更多
基金financially supported by the National Key Research and Development Program of China(No.2019YFC1805400)。
文摘As a new technical means that can detect abnormal signs of water inrush in advance and give an early warning,the automatic monitoring and early warning of water inrush in mines has been widely valued in recent years.Due to the many factors affecting water inrush and the complicated water inrush mechanism,many factors close to water inrush may have precursory abnormal changes.At present,the existing monitoring and early warning system mainly uses a few monitoring indicators such as groundwater level,water influx,and temperature,and performs water inrush early warning through the abnormal change of a single factor.However,there are relatively few multi-factor comprehensive early warning identification models.Based on the analysis of the abnormal changes of precursor factors in multiple water inrush cases,11 measurable and effective indicators including groundwater flow field,hydrochemical field and temperature field are proposed.Finally,taking Hengyuan coal mine as an example,6 indicators with long-term monitoring data sequences were selected to establish a single-index hierarchical early-warning recognition model,a multi-factor linear recognition model,and a comprehensive intelligent early-warning recognition model.The results show that the correct rate of early warning can reach 95.2%.
文摘Flow of fluids within biological tissues often meets with resistance that causes a rate-and size-dependent material behavior known as poroelasticity.Characterizing poroelasticity can provide insight into a broad range of physiological functions,and is done qualitatively in the clinic by palpation.Indentation has been widely used for characterizing poroelasticity of soft materials,where quantitative interpretation of indentation requires a model of the underlying physics,and such existingmodels are well established for cases of small strain and modest force relaxationWe showed here that existing models are inadequate for large relaxation,where the force on the indenter at a prescribed depth at long-time scale drops to below half of the initially peak force.We developed an indentation theory for such cases of large relaxation,based upon Biot theory and a generalized Hertz contact model.We demonstrated that proposed theory is suitable for biological tissues(e.g.,spleen,kidney,skin and human cirrhosis liver)with both small and large relaxations.The proposed method would be a powerful tool to characterize poroelastic properties of biological materials for various applications such as pathological study and disease diagnosis.
文摘Objective: This study is designed to observe the chronic toxicity after the administration of mulberry sea-buckthorn beverage concentrate for 3 months on rats and to predict the possible adverse effect and the potential toxicity target organs. Method: The rats (SPF level) were randomly divided into high-dose (20 mL/kg BW), middle-dose (10 mL/kg BW), low-dose (5 mL/kg BW) groups and negative control group (20 mL/kg BW of purified water) with 30 rats in each group. Each group was orally given mulberry sea-buckthorn beverage concentrate for 3 months and recovered by stop feeding samples for 2 weeks for a recovery observation. The rats’ general condition, the organ coefficient, the indexes of hematology and blood biochemistry and the histological changes of the main organs were determined. Result: The appearance and behavior of activity in rats showed no anomalies in all these groups and all the rats put on weight during this period. Comparing to the negative control group, no obvious differences were observed in the weekly weight and organ coefficient of each dose group. After 3 months of administration, HGB in both mulberry sea-buckthorn beverage concentrate low-dose group and high-dose group were increased. No significant differences were observed in the indexes of hematology after 2 weeks of recovery. CREA in low-dose, middle-dose and high-dose groups were significantly increased after 3 months of administration and it remained in the high level in middle-dose and high-dose group even after 2 weeks of recovery. No drug-related lesions were observed in the histological changes of major organs. Conclusion: The results show that long term use of mulberry concentrated sea-buckthorn beverage can lead to increased CREA, which suggested kidney toxicity. Although no obvious pathological change was found in kidney, we should pay attention to chronic kidney damage in the further research.
基金Fundamental Research Funds for the Universities,Grant/Award Numbers:2020ZDPY0201,2022QN1061National Key Research and Development Project of China,Grant/Award Number:2019YFC1805400+1 种基金National Science Foundation of Jiangsu Province,Grant/Award Number:BK20210524National Natural Science Foundation,Grant/Award Number:42202268。
文摘For the sake of mine water drainage and sustainable groundwater protection,the new approach of mine water deep geological storage(MWDGS)is highly necessary to save water resources in the semi-arid region of China.However,up to now,little academic research has been done on mine water geological storage.Given this situation,the hydrogeological feasibility of MWDGS was explored in Baotashan coarse sandstone(BCS)of Jurassic measure in Ordos Basin.The results show that the white-gray BCS with a fragile skeleton of quartz(41.4%),feldspar(21.1%),and clay minerals(16.4%)provides the potential variable-void for mine water;and its hydro-chemical type of BCS aquifer is CO_(3)-Na and Cl-Na.As the burial depth increases,the strong alkaline groundwater is in stagnant and poor recharge-runoff-discharge condition.The lab test shows that the pores whose diameter is over 10μm could be treated as the main storage of mine water;and the effective porosity varies from 1.36%to 3.46%.When mine water is injected,the strong hydrodynamics of mine water storage would change the permeability significantly and about 0.201%soluble solids would be dissolved.Partial clay minerals obstruct the pores and induce the saturated phase of high permeability to evolve into steady phase of lower permeability.Under the condition of nonhydraulic fracturing during continuous storage,the heterogeneous anisotropic medium obtained by Transition PRObability GeoStatistics(TPROGS)shows that the capacity of BCS aquifer is 0.455 to 1.226Mm^(3)for 1 km^(2)in the study area.The simulation shows that the groundwater mound in well-scale and mine-scale would be formed.The groundwater quality characteristics of“Three Zone”would occur around and gradually drop to approximate the original brine within 10 years.The hydrogeological feasibility reveals that this approach is useful for the well design and groundwater environment management during the mine water deep geological storage project in the Ordos basin.
基金This work was financially supported by the Natural Science Foundation of Heilongjiang Province(No.LH2021A012).
文摘PbTiO_(3)-based piezoelectric ceramics are key materials for developing various electromechanical transduc-ers.For high-power ultrasonic transducers,piezoelectric ceramics are required to possess large piezo-electric coefficient(d_(33))and high mechanical quality factor(Q_(m)).Although acceptor dopants can im-prove Q_(m),they also deteriorate d_(33).If suitable piezoelectricity-beneficial donor dopants can be intro-duced into acceptor-doped ceramics,it is very possible to obtain large d_(33)and high Q_(m)simultaneously in donor and acceptor co-doped ceramics.In this work,a series of x mol%Sm and y mol%Mn co-doped Pb(Mg_(1/3)Nb_(2/3))O_(3)-30PbTiO_(3)(PMN-30PT:x Sm,y Mn)ceramics were prepared by the solid-phase sintered method.The crystal structure,local domain structure and electromechanical properties were sys-tematically analyzed.Optimal performances were obtained in PMN-30PT:2.5Sm,1-2Mn ceramics with d_(33)=860-543 pC/N,Q_(m)=495-754,and dielectric loss tanδ=0.0055-0.0086.This high performance origi-nates from the combined effects of(Mn″Ti−V_(o)^(••))^(×)defect dipoles and the local structural heterogeneity.
基金The authors thank Nan Meng at the University of Hong Kong for fruitful discussions,Dr.Ping Su at the Graduate School at Shenzhen,Tsinghua University for providing some samples,and Yong Wu at University of Electronic Science and Technology of China for help in experiments.The authors gratefully acknowledge the following funding:University of Hong Kong(104004582,104005009)Research Grants Council,University Grants Committee(RGC,UGC)(17203217).
文摘Digital holography records the entire wavefront of an object,including amplitude and phase.To reconstruct the object numerically,we can backpropagate the hologram with Fresnel–Kirchhoff integralbased algorithms such as the angular spectrum method and the convolution method.Although effective,these techniques require prior knowledge,such as the object distance,the incident angle between the two beams,and the source wavelength.Undesirable zero-order and twin images have to be removed by an additional filtering operation,which is usually manual and consumes more time in off-axis configuration.In addition,for phase imaging,the phase aberration has to be compensated,and subsequently an unwrapping step is needed to recover the true object thickness.The former either requires additional hardware or strong assumptions,whereas the phase unwrapping algorithms are often sensitive to noise and distortion.Furthermore,for a multisectional object,an all-in-focus image and depth map are desired for many applications,but current approaches tend to be computationally demanding.We propose an end-to-end deep learning framework,called a holographic reconstruction network,to tackle these holographic reconstruction problems.Through this data-driven approach,we show that it is possible to reconstruct a noise-free image that does not require any prior knowledge and can handle phase imaging as well as depth map generation.
基金supported by the National Natural Science Foundation of China(No.41772245)the National Key Research and Development Program of China(No.2019YFC1805400)the Fundamental Research Funds for the Central Universities(No.2020ZDPY0201)。
文摘Gibberellic acid(GA_(3))is widely used in agriculture and maybe transfer with groundwater flow,which is an endocrine disruptor,but few studies have focused on the transformation pathway and toxicity assessment of GA_(3)and its products.Here,GA_(3)and its transformation products in aqueous solution were identified and quantified by liquid chromatography mass spectrometry hybrid ion trap time-of-flight(LCMS-IT-TOF)and high-performance liquid chromatography(HPLC),respectively.The results showed that the half-life of GA_(3)transformation in ultrapure water was 16.1–24.6 days at p H=2.0–8.0,with the lowest half-life occurring at p H=8.0 and highest half-life occurring at p H=3.3.Isomerized gibberellic acid(Iso-GA_(3))and gibberellenic acid(GEA)were the main transformation products with a little hydroxy gibberellic acid(OH-GA_(3)).In North China groundwater,the mass balance of GA_(3)and its products was 76.2%,including Iso-GA_(3)(58%),GEA(7.9%),GA_(3)(7.3%)and OH-GA_(3)(3%)after reaching transformation equilibrium.Using Gaussian 09 for chemical computation,it was found that the transformation mechanism of GA_(3)was dependent upon the bond energy and the stereochemical feature of its molecular structure.GA_(3)always isomerized from theγ-lactone ring due to the lowest bond energy between the oxygen terminus of theγ-lactone ring and A ring.While GA_(3)and its transformation products all had developmental toxicity,the predicated LC 50(96 hr)and LD 50 of the main products of GA_(3)were much lower than those of GA_(3),indicating GA_(3)would be transformed into higher toxicity derivatives in water environments,posing a significant health risk to humans and the environment.
文摘Topography of acoustic response characteristics in the auditory cortex (AC) of the Kunming (KM) mouse has been examined by using microelectrode recording techniques. Based on best-frequency (BF) maps, both the primary auditory field (Al) and the anterior auditory field (AAF) are tonotopically organized with a counter running frequency gradient. within an isofrequency stripe, the width of the frequency-threshold curves of single neurons increases, and minimum threshold (MT) decreases towards more ventral locations. BFs in Al and AAF range from 4 to 38 kHz. Auditory neurons with BFs above 40 kHz are located at the rostrodorsal part of the AC. The findings suggest that the KM mouse is a good model suitable for auditory research.
