In Na-ion batteries,O3-type layered oxide cathode materials encounter challenges such as particle cracking,oxygen loss,electrolyte side reactions,and multi-phase transitions during the charge/discharge process.This st...In Na-ion batteries,O3-type layered oxide cathode materials encounter challenges such as particle cracking,oxygen loss,electrolyte side reactions,and multi-phase transitions during the charge/discharge process.This study focuses on surface coating with NiTiO_(3) achieved via secondary heat treatment using a coating precursor and the surface material.Through in-situ x-ray diffraction(XRD)and differential electrochemical mass spectrometry(DEMS),along with crystal structure characterizations of post-cycling materials,it was determined that the NiTiO_(3) coating layer facilitates the formation of a stable lattice structure,effectively inhibiting lattice oxygen loss and reducing side reaction with the electrolyte.This enhancement in cycling stability was evidenced by a capacity retention of approximately 74%over 300 cycles at 1 C,marking a significant 30%improvement over the initial sample.Furthermore,notable advancements in rate performance were observed.Experimental results indicate that a stable and robust surface structure substantially enhances the overall stability of the bulk phase,presenting a novel approach for designing layered oxide cathodes with higher energy density.展开更多
Intercalation provides to the host materials a means for controlled variation of many physical/chemical properties and dominates the reactions in metal‐ion batteries.Of particular interest is the graphite intercalati...Intercalation provides to the host materials a means for controlled variation of many physical/chemical properties and dominates the reactions in metal‐ion batteries.Of particular interest is the graphite intercalation compounds with intriguing staging structures,which however are still unclear,especially in their nanostructure and dynamic transition mechanism.Herein,the nature of the staging structure and evolution of the lithium(Li)‐intercalated graphite was revealed by cryogenic‐transmission electron microscopy and other methods at the nanoscale.The intercalated Li‐ions distribute unevenly,generating local stress and dislocations in the graphitic structure.Each staging compound is found macroscopically ordered but microscopically inhomogeneous,exhibiting a localized‐domains structural model.Our findings uncover the correlation between the long‐range ordered structure and short‐range domains,refresh the insights on the staging structure and transition of Li‐intercalated/deintercalated graphite,and provide effective ways to enhance the reaction kinetic in rechargeable batteries by defect engineering.展开更多
·AIM: To report outcomes of endoscopy-assisted vitrectomy(EAV) in patients with chronic hypotony following severe ocular trauma or vitrectomy.·METHODS: This was a retrospective, noncomparative case series. C...·AIM: To report outcomes of endoscopy-assisted vitrectomy(EAV) in patients with chronic hypotony following severe ocular trauma or vitrectomy.·METHODS: This was a retrospective, noncomparative case series. Ciliary bodies were evaluated using ultrasound biomicroscopy pre-operatively and direct visualisation intraoperatively. All selected individuals(seven patients/seven eyes) underwent EAV. Removal of ciliary membrane and traction, gas/silicone oil tamponade(GT/SOT), and scleral buckling(SB) were performed in selected eyes. Outcome measurements mainly included intraocular pressure(IOP) and best-corrected visual acuity(BCVA).·RESULTS: Seven eyes from 7 male aphakic patients with a mean age of 45(range, 20-68)y were included in this study;the average follow-up time was 12(9-15)mo. GT was performed in 2 eyes;membrane peeling(MP) and SOT in 2 eyes;and MP, SOT, and SB in 3 eyes. The mean preand post-operative IOP were 4.5(range, 4.0±0.11 to 4.8±0.2) mm Hg and 9.9(range, 5.6±0.17 to 12.1±0.2) mm Hg at 52wk(12mo), respectively. BCVA improved in six eyes;one eye still showed light perception, and no bulbi phthisis was observed.·CONCLUSION: Endoscopy offers improved judgment and recognition and has an improved prognosis for chronic hypotony. Therefore, endoscopy can be an effective and promising operative technique for chronic traumatic hypotony management.展开更多
This study aims to explore the effect and mechanism of Jiao-tai-wan (JTW) on systemic and tissue-specific inflammation and insulin resistance in obesity-resistant (OR) rats with chronic partial sleep deprivation ...This study aims to explore the effect and mechanism of Jiao-tai-wan (JTW) on systemic and tissue-specific inflammation and insulin resistance in obesity-resistant (OR) rats with chronic partial sleep deprivation (PSD). OR rats with PSD were orally given JTW and Estazolam for 4 weeks. The amount of food intake and metabolic parameters such as body weight increase rate, fasting plasma glucose (FPG), fasting insulin (FINS), homeostasis model assessment-insulin resistance (HOMA-IR) and plasma inflammatory markers were measured. The expression levels of circadian proteins cryptochrome 1 (Cryl) and cryptochrome 2 (Cry2) in hypothalamus, adipose and liver tissues were also determined. Meanwhile, the mRNA expression of inflammatory markers, activity of nuclear factor kappa B (NF-κB) p65 protein, as well as the expression levels of insulin signaling pathway proteins in hypothalamus, adipose and liver tissues were measured. Additionally, cyclic adenosine 3', 5'-monophosphate (cAMP) and activity of vasodilator-stimulated phosphoprotein (VASP) in hypothalamus tissue were measured. JTW significantly decreased the body weight increase rate and food intake, ameliorated systemic inflammation and insulin resistance. JTW effectively ameliorated inflammation and increased PI3K/AKT signaling activation in hypothalamus, adipose and liver. Interestingly, all these changes were associated with the up-regulation of circadian gene Cryl and Cry2 protein expression. We also found that in hypothalamus tissue of PSD rats, down-regulation of Cryl and Cry2 activated cAMP/PKA signaling and then led to inflammation, while JTW inhibited this signaling. These results suggested that JTW has the beneficial effect on ameliorating inflammation and insulin resistance in partially sleep-deprived rats by up-regulating Cry expression.展开更多
In shale reservoirs,the organic pores with various structures formed during the thermal evolution of organic matter are the main storage site for adsorbed methane.However,in the process of thermal evolution,the adsorp...In shale reservoirs,the organic pores with various structures formed during the thermal evolution of organic matter are the main storage site for adsorbed methane.However,in the process of thermal evolution,the adsorption characteristics of methane in multi type and multi-scale organic matter pores have not been sufficiently studied.In this study,the molecular simulation method was used to study the adsorption characteristics of methane based on the geological conditions of Longmaxi Formation shale reservoir in Sichuan Basin,China.The results show that the characteristics of pore structure will affect the methane adsorption characteristics.The adsorption capacity of slit-pores for methane is much higher than that of cylindrical pores.The groove space inside the pore will change the density distribution of methane molecules in the pore,greatly improve the adsorption capacity of the pore,and increase the pressure sensitivity of the adsorption process.Although the variation of methane adsorption characteristics of different shapes is not consistent with pore size,all pores have the strongest methane adsorption capacity when the pore size is about 2 nm.In addition,the changes of temperature and pressure during the thermal evolution are also important factors to control the methane adsorption characteristics.The pore adsorption capacity first increases and then decreases with the increase of pressure,and increases with the increase of temperature.In the early stage of thermal evolution,pore adsorption capacity is strong and pressure sensitivity is weak;while in the late stage,it is on the contrary.展开更多
AIM: To evaluate the protective effects of lipoic acid-niacin(N2 L) dimers against blue light(BL)-induced oxidative damage to human retinal pigment epithelium(hRPE) cells in vitro.METHODS: h RPE cells were divided int...AIM: To evaluate the protective effects of lipoic acid-niacin(N2 L) dimers against blue light(BL)-induced oxidative damage to human retinal pigment epithelium(hRPE) cells in vitro.METHODS: h RPE cells were divided into a control group(CG), a BL group, an N2 L plus BL irradiation group, an α-lipoic acid(ALA) plus BL group, an ALA-only group, and an N2 L-only group. hRPE cellular viability was detected by performing 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium(MTT) bromide assays, and apoptosis was evaluated by annexin-V-PE/7-AAD staining followed by flow cytometry. Ultrastructural changes in subcellular organelles were observed by transmission electron microscopy. Reactive oxygen species formation was assayed by flow cytometry. The expression levels of the apoptosis-related proteins BCL-2 associated X protein(BAX), B-cell leukmia/lymphoma 2(BCL-2), and caspase-3 were quantified by Western blot analysis.RESULTS: BL exposure with a light density of 4±0.5 mW/cm2 exceeding 6 h caused hRPE toxicity, whereas treatment with a high dose of N2 L(100 mol/L) or ALA(150 mol/L) maintained cell viability at control levels. BL exposure caused vacuole-like degeneration, mitochondrial swelling, and reduced microvillus formation;however, a high dose of N2 L or ALA maintained the ultrastructure of hRPE cells and their organelles. High doses of N2 L and ALA also protected hRPE cells from BL-induced apoptosis, which was confirmed by Western blot analysis: BCL-2 expression significantly increased, while BAX and caspase-3 expression slightly decreased compared to the CG.CONCLUSION: High-dose N2 L treatment(>100 mol/L) can reduce oxidative damage in degenerating hRPE cells exposed to BL with an efficacy similar to ALA.展开更多
This paper presents Part II of a review on DFACS,which specifically focuses on the modeling and analysis of disturbances and noises in DFACSs.In Part I,the system composition and dynamics model of the DFACS were prese...This paper presents Part II of a review on DFACS,which specifically focuses on the modeling and analysis of disturbances and noises in DFACSs.In Part I,the system composition and dynamics model of the DFACS were presented.In this paper,we discuss the effects of disturbance forces and noises on the system,and summarize various analysis and modeling methods for these interferences,including the integral method,frequency domain analysis method,and magnitude evaluation method.By analyzing the impact of disturbances and noises on the system,the paper also summarizes the system’s performance under slight interferences.Additionally,we highlight current research difficulties in the field of DFACS noise analysis.Overall,this paper provides valuable insights into the modeling and analysis of disturbances and noises in DFACSs,and identifies key areas for future research.展开更多
The Drag-Free and Attitude Control System(DFACS)is a critical platform for various space missions,including high precision satellite navigation,geoscience and gravity field measurement,and space scientific experiments...The Drag-Free and Attitude Control System(DFACS)is a critical platform for various space missions,including high precision satellite navigation,geoscience and gravity field measurement,and space scientific experiments.This paper presents a comprehensive review of over sixty years of research on the design and dynamics model of DFACS.Firstly,we examine the open literature on DFACS and its applications in Drag-Free missions,providing readers with necessary background information on the field.Secondly,we analyze the system configurations and main characteristics of different DFACSs,paying particular attention to the coupling mechanism between the system configuration and dynamics model.Thirdly,we summarize the dynamics modeling methods and main dynamics models of DFACS from multiple perspectives,including common fundamentals and specific applications.Lastly,we identify current challenges and technological difficulties in the system design and dynamics modeling of DFACS,while suggesting potential avenues for future research.This paper aims to provide readers with a comprehensive understanding of the state-of-the-art in DFACS research,as well as the future prospects and challenges in this field.展开更多
Deep learning and computer vision have become emerging tools for diseased plant phenotyping.Most previous studies focused on image-level disease classification.In this paper,pixel-level phenotypic feature(the distribu...Deep learning and computer vision have become emerging tools for diseased plant phenotyping.Most previous studies focused on image-level disease classification.In this paper,pixel-level phenotypic feature(the distribution of spot)was analyzed by deep learning.Primarily,a diseased leaf dataset was collected and the corresponding pixel-level annotation was contributed.A dataset of apple leaves samples was used for training and optimization.Another set of grape and strawberry leaf samples was used as an extra testing dataset.Then,supervised convolutional neural networks were adopted for semantic segmentation.Moreover,the possibility of weakly supervised models for disease spot segmentation was also explored.Grad-CAM combined with ResNet-50(ResNet-CAM),and that combined with a few-shot pretrained U-Net classifier for weakly supervised leaf spot segmentation(WSLSS),was designed.They were trained using image-level annotations(healthy versus diseased)to reduce the cost of annotation work.Results showed that the supervised DeepLab achieved the best performance(IoU=0.829)on the apple leaf dataset.The weakly supervised WSLSS achieved an IoU of 0.434.When processing the extra testing dataset,WSLSS realized the best IoU of 0.511,which was even higher than fully supervised DeepLab(IoU=0.458).Although there was a certain gap in IoU between the supervised models and weakly supervised ones,WSLSS showed stronger generalization ability than supervised models when processing the disease types not involved in the training procedure.Furthermore,the contributed dataset in this paper could help researchers get a quick start on designing their new segmentation methods in future studies.展开更多
Heavy metal pollution is becoming a prominent stress on plants.Plants contaminated with heavy metals undergo changes in external morphology and internal structure,and heavy metals can accumulate through the food chain...Heavy metal pollution is becoming a prominent stress on plants.Plants contaminated with heavy metals undergo changes in external morphology and internal structure,and heavy metals can accumulate through the food chain,threatening human health.Detecting heavy metal stress on plants quickly,accurately,and nondestructively helps to achieve precise management of plant growth status and accelerate the breeding of heavy metal-resistant plant varieties.Traditional chemical reagent-based detection methods are laborious,destructive,time-consuming,and costly.The internal and external structures of plants can be altered by heavy metal contamination,which can lead to changes in plants'absorption and reflection of light.Visible/near-infrared(V/NIR)spectroscopy can obtain plant spectral information,and hyperspectral imaging(HSI)can obtain spectral and spatial information in simple,speedy,and nondestructive ways.These 2 technologies have been the most widely used high-throughput phenotyping technologies of plants.This review summarizes the application of V/NIR spectroscopy and HSI in plant heavy metal stress phenotype analysis as well as introduces the method of combining spectroscopy with machine learning approaches for high-throughput phenotyping of plant heavy metal stress,including unstressed and stressed identification,stress types identification,stress degrees identification,and heavy metal content estimation.The vegetation indexes,full-range spectra,and feature bands identified by different plant heavy metal stress phenotyping methods are reviewed.The advantages,limitations,challenges,and prospects of V/NIR spectroscopy and HSI for plant heavy metal stress phenotyping are discussed.Further studies are needed to promote the research and application of V/NIR spectroscopy and HSI for plant heavy metal stress phenotyping.展开更多
Herbicides and heavy metals are hazardous substances of environmental pollution,resulting in plant stress and harming humans and animals.Identification of stress types can help trace stress sources,manage plant growth...Herbicides and heavy metals are hazardous substances of environmental pollution,resulting in plant stress and harming humans and animals.Identification of stress types can help trace stress sources,manage plant growth,and improve stress-resistant breeding.In this research,hyperspectral imaging(HSI)and chlorophyll fluorescence imaging(Chl-FI)were adopted to identify the rice plants under two types of herbicide stresses(butachlor(DCA)and quinclorac(ELK))and two types of heavy metal stresses(cadmium(Cd)and copper(Cu)).展开更多
Rapid determination of chlorophyll content is significant for evaluating cotton’s nutritional and physiological status.Hyperspectral technology equipped with multivariate analysis methods has been widely used for chl...Rapid determination of chlorophyll content is significant for evaluating cotton’s nutritional and physiological status.Hyperspectral technology equipped with multivariate analysis methods has been widely used for chlorophyll content detection.However,the model developed on one batch or variety cannot produce the same effect for another due to variations,such as samples and measurement conditions.展开更多
基金Project supported by the National Key R&D Program of China (Grant No.2022YFB2402500)the National Natural Science Foundation of China (Grant Nos.52122214,92372116,and 52394174)+2 种基金Youth Innovation Promotion Association of the Chinese Academy of Sciences (Grant No.2020006)Jiangsu Province Carbon Peak and Neutrality Innovation Program (Industry tackling on prospect and key technology BE2022002-5)Guangxi Power Grid Project (Grant No.GXKJXM20210260)。
文摘In Na-ion batteries,O3-type layered oxide cathode materials encounter challenges such as particle cracking,oxygen loss,electrolyte side reactions,and multi-phase transitions during the charge/discharge process.This study focuses on surface coating with NiTiO_(3) achieved via secondary heat treatment using a coating precursor and the surface material.Through in-situ x-ray diffraction(XRD)and differential electrochemical mass spectrometry(DEMS),along with crystal structure characterizations of post-cycling materials,it was determined that the NiTiO_(3) coating layer facilitates the formation of a stable lattice structure,effectively inhibiting lattice oxygen loss and reducing side reaction with the electrolyte.This enhancement in cycling stability was evidenced by a capacity retention of approximately 74%over 300 cycles at 1 C,marking a significant 30%improvement over the initial sample.Furthermore,notable advancements in rate performance were observed.Experimental results indicate that a stable and robust surface structure substantially enhances the overall stability of the bulk phase,presenting a novel approach for designing layered oxide cathodes with higher energy density.
基金support from the National Natural Science Foundation of China(NSFC nos.52172257,22005334,21773301 and 52022106)the Natural Science Foundation of Beijing(grant no.Z200013).
文摘Intercalation provides to the host materials a means for controlled variation of many physical/chemical properties and dominates the reactions in metal‐ion batteries.Of particular interest is the graphite intercalation compounds with intriguing staging structures,which however are still unclear,especially in their nanostructure and dynamic transition mechanism.Herein,the nature of the staging structure and evolution of the lithium(Li)‐intercalated graphite was revealed by cryogenic‐transmission electron microscopy and other methods at the nanoscale.The intercalated Li‐ions distribute unevenly,generating local stress and dislocations in the graphitic structure.Each staging compound is found macroscopically ordered but microscopically inhomogeneous,exhibiting a localized‐domains structural model.Our findings uncover the correlation between the long‐range ordered structure and short‐range domains,refresh the insights on the staging structure and transition of Li‐intercalated/deintercalated graphite,and provide effective ways to enhance the reaction kinetic in rechargeable batteries by defect engineering.
基金Supported by the Guangdong Province Natural Science Foundation (No.2019A1515011732)Guangzhou Science and Technology Foundation of Guangdong Province (No.202002030413)。
文摘·AIM: To report outcomes of endoscopy-assisted vitrectomy(EAV) in patients with chronic hypotony following severe ocular trauma or vitrectomy.·METHODS: This was a retrospective, noncomparative case series. Ciliary bodies were evaluated using ultrasound biomicroscopy pre-operatively and direct visualisation intraoperatively. All selected individuals(seven patients/seven eyes) underwent EAV. Removal of ciliary membrane and traction, gas/silicone oil tamponade(GT/SOT), and scleral buckling(SB) were performed in selected eyes. Outcome measurements mainly included intraocular pressure(IOP) and best-corrected visual acuity(BCVA).·RESULTS: Seven eyes from 7 male aphakic patients with a mean age of 45(range, 20-68)y were included in this study;the average follow-up time was 12(9-15)mo. GT was performed in 2 eyes;membrane peeling(MP) and SOT in 2 eyes;and MP, SOT, and SB in 3 eyes. The mean preand post-operative IOP were 4.5(range, 4.0±0.11 to 4.8±0.2) mm Hg and 9.9(range, 5.6±0.17 to 12.1±0.2) mm Hg at 52wk(12mo), respectively. BCVA improved in six eyes;one eye still showed light perception, and no bulbi phthisis was observed.·CONCLUSION: Endoscopy offers improved judgment and recognition and has an improved prognosis for chronic hypotony. Therefore, endoscopy can be an effective and promising operative technique for chronic traumatic hypotony management.
基金This study was supported by National Natural Science Foundation of China (No. 81373871 and No. 81473637).
文摘This study aims to explore the effect and mechanism of Jiao-tai-wan (JTW) on systemic and tissue-specific inflammation and insulin resistance in obesity-resistant (OR) rats with chronic partial sleep deprivation (PSD). OR rats with PSD were orally given JTW and Estazolam for 4 weeks. The amount of food intake and metabolic parameters such as body weight increase rate, fasting plasma glucose (FPG), fasting insulin (FINS), homeostasis model assessment-insulin resistance (HOMA-IR) and plasma inflammatory markers were measured. The expression levels of circadian proteins cryptochrome 1 (Cryl) and cryptochrome 2 (Cry2) in hypothalamus, adipose and liver tissues were also determined. Meanwhile, the mRNA expression of inflammatory markers, activity of nuclear factor kappa B (NF-κB) p65 protein, as well as the expression levels of insulin signaling pathway proteins in hypothalamus, adipose and liver tissues were measured. Additionally, cyclic adenosine 3', 5'-monophosphate (cAMP) and activity of vasodilator-stimulated phosphoprotein (VASP) in hypothalamus tissue were measured. JTW significantly decreased the body weight increase rate and food intake, ameliorated systemic inflammation and insulin resistance. JTW effectively ameliorated inflammation and increased PI3K/AKT signaling activation in hypothalamus, adipose and liver. Interestingly, all these changes were associated with the up-regulation of circadian gene Cryl and Cry2 protein expression. We also found that in hypothalamus tissue of PSD rats, down-regulation of Cryl and Cry2 activated cAMP/PKA signaling and then led to inflammation, while JTW inhibited this signaling. These results suggested that JTW has the beneficial effect on ameliorating inflammation and insulin resistance in partially sleep-deprived rats by up-regulating Cry expression.
基金This work was supported by the National Natural Science Foundation of China(Nos.41772141,41972171)the Natural Science Foundation of Jiangsu Province(BK20181362),the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD).
文摘In shale reservoirs,the organic pores with various structures formed during the thermal evolution of organic matter are the main storage site for adsorbed methane.However,in the process of thermal evolution,the adsorption characteristics of methane in multi type and multi-scale organic matter pores have not been sufficiently studied.In this study,the molecular simulation method was used to study the adsorption characteristics of methane based on the geological conditions of Longmaxi Formation shale reservoir in Sichuan Basin,China.The results show that the characteristics of pore structure will affect the methane adsorption characteristics.The adsorption capacity of slit-pores for methane is much higher than that of cylindrical pores.The groove space inside the pore will change the density distribution of methane molecules in the pore,greatly improve the adsorption capacity of the pore,and increase the pressure sensitivity of the adsorption process.Although the variation of methane adsorption characteristics of different shapes is not consistent with pore size,all pores have the strongest methane adsorption capacity when the pore size is about 2 nm.In addition,the changes of temperature and pressure during the thermal evolution are also important factors to control the methane adsorption characteristics.The pore adsorption capacity first increases and then decreases with the increase of pressure,and increases with the increase of temperature.In the early stage of thermal evolution,pore adsorption capacity is strong and pressure sensitivity is weak;while in the late stage,it is on the contrary.
基金Supported by the Guangzhou Science and Technology Foundation of Guangdong Province (No.2014J4100035 No.2014KP000071)
文摘AIM: To evaluate the protective effects of lipoic acid-niacin(N2 L) dimers against blue light(BL)-induced oxidative damage to human retinal pigment epithelium(hRPE) cells in vitro.METHODS: h RPE cells were divided into a control group(CG), a BL group, an N2 L plus BL irradiation group, an α-lipoic acid(ALA) plus BL group, an ALA-only group, and an N2 L-only group. hRPE cellular viability was detected by performing 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium(MTT) bromide assays, and apoptosis was evaluated by annexin-V-PE/7-AAD staining followed by flow cytometry. Ultrastructural changes in subcellular organelles were observed by transmission electron microscopy. Reactive oxygen species formation was assayed by flow cytometry. The expression levels of the apoptosis-related proteins BCL-2 associated X protein(BAX), B-cell leukmia/lymphoma 2(BCL-2), and caspase-3 were quantified by Western blot analysis.RESULTS: BL exposure with a light density of 4±0.5 mW/cm2 exceeding 6 h caused hRPE toxicity, whereas treatment with a high dose of N2 L(100 mol/L) or ALA(150 mol/L) maintained cell viability at control levels. BL exposure caused vacuole-like degeneration, mitochondrial swelling, and reduced microvillus formation;however, a high dose of N2 L or ALA maintained the ultrastructure of hRPE cells and their organelles. High doses of N2 L and ALA also protected hRPE cells from BL-induced apoptosis, which was confirmed by Western blot analysis: BCL-2 expression significantly increased, while BAX and caspase-3 expression slightly decreased compared to the CG.CONCLUSION: High-dose N2 L treatment(>100 mol/L) can reduce oxidative damage in degenerating hRPE cells exposed to BL with an efficacy similar to ALA.
基金This research was supported by National Key R&D Program of China:Gravitational Wave Detection Project(Nos.2021YFC2202601,2021YFC2202603)National Natural Science Foundation of China(No.12172288).
文摘This paper presents Part II of a review on DFACS,which specifically focuses on the modeling and analysis of disturbances and noises in DFACSs.In Part I,the system composition and dynamics model of the DFACS were presented.In this paper,we discuss the effects of disturbance forces and noises on the system,and summarize various analysis and modeling methods for these interferences,including the integral method,frequency domain analysis method,and magnitude evaluation method.By analyzing the impact of disturbances and noises on the system,the paper also summarizes the system’s performance under slight interferences.Additionally,we highlight current research difficulties in the field of DFACS noise analysis.Overall,this paper provides valuable insights into the modeling and analysis of disturbances and noises in DFACSs,and identifies key areas for future research.
基金This research was supported by National Key R&D Program of China:Gravitational Wave Detection Project,China(Nos.2021YFC2202601,2021YFC2202603)National Natural Science Foundation of China(No.12172288).
文摘The Drag-Free and Attitude Control System(DFACS)is a critical platform for various space missions,including high precision satellite navigation,geoscience and gravity field measurement,and space scientific experiments.This paper presents a comprehensive review of over sixty years of research on the design and dynamics model of DFACS.Firstly,we examine the open literature on DFACS and its applications in Drag-Free missions,providing readers with necessary background information on the field.Secondly,we analyze the system configurations and main characteristics of different DFACSs,paying particular attention to the coupling mechanism between the system configuration and dynamics model.Thirdly,we summarize the dynamics modeling methods and main dynamics models of DFACS from multiple perspectives,including common fundamentals and specific applications.Lastly,we identify current challenges and technological difficulties in the system design and dynamics modeling of DFACS,while suggesting potential avenues for future research.This paper aims to provide readers with a comprehensive understanding of the state-of-the-art in DFACS research,as well as the future prospects and challenges in this field.
基金supported by the National Natural Science Foundation of China(61705195).
文摘Deep learning and computer vision have become emerging tools for diseased plant phenotyping.Most previous studies focused on image-level disease classification.In this paper,pixel-level phenotypic feature(the distribution of spot)was analyzed by deep learning.Primarily,a diseased leaf dataset was collected and the corresponding pixel-level annotation was contributed.A dataset of apple leaves samples was used for training and optimization.Another set of grape and strawberry leaf samples was used as an extra testing dataset.Then,supervised convolutional neural networks were adopted for semantic segmentation.Moreover,the possibility of weakly supervised models for disease spot segmentation was also explored.Grad-CAM combined with ResNet-50(ResNet-CAM),and that combined with a few-shot pretrained U-Net classifier for weakly supervised leaf spot segmentation(WSLSS),was designed.They were trained using image-level annotations(healthy versus diseased)to reduce the cost of annotation work.Results showed that the supervised DeepLab achieved the best performance(IoU=0.829)on the apple leaf dataset.The weakly supervised WSLSS achieved an IoU of 0.434.When processing the extra testing dataset,WSLSS realized the best IoU of 0.511,which was even higher than fully supervised DeepLab(IoU=0.458).Although there was a certain gap in IoU between the supervised models and weakly supervised ones,WSLSS showed stronger generalization ability than supervised models when processing the disease types not involved in the training procedure.Furthermore,the contributed dataset in this paper could help researchers get a quick start on designing their new segmentation methods in future studies.
基金supported by the China Manned Space Engineering Program(Fluid Physics Experimental Rack and the Priority Research Program of Space Station)the National Natural Science Foundation of China(Grant No.12032020).
基金supported by the Research and Development of Cotton Root Phenotype Information Collection Device and Root Detection Technology(grant number:GJHZ202205)the National Natural Science Foundation of China(grant number:62305166)Zhejiang Province Key Laboratory of Smart Management and Application of Modern Agricultural Resources(grant number:2020E10017).
文摘Heavy metal pollution is becoming a prominent stress on plants.Plants contaminated with heavy metals undergo changes in external morphology and internal structure,and heavy metals can accumulate through the food chain,threatening human health.Detecting heavy metal stress on plants quickly,accurately,and nondestructively helps to achieve precise management of plant growth status and accelerate the breeding of heavy metal-resistant plant varieties.Traditional chemical reagent-based detection methods are laborious,destructive,time-consuming,and costly.The internal and external structures of plants can be altered by heavy metal contamination,which can lead to changes in plants'absorption and reflection of light.Visible/near-infrared(V/NIR)spectroscopy can obtain plant spectral information,and hyperspectral imaging(HSI)can obtain spectral and spatial information in simple,speedy,and nondestructive ways.These 2 technologies have been the most widely used high-throughput phenotyping technologies of plants.This review summarizes the application of V/NIR spectroscopy and HSI in plant heavy metal stress phenotype analysis as well as introduces the method of combining spectroscopy with machine learning approaches for high-throughput phenotyping of plant heavy metal stress,including unstressed and stressed identification,stress types identification,stress degrees identification,and heavy metal content estimation.The vegetation indexes,full-range spectra,and feature bands identified by different plant heavy metal stress phenotyping methods are reviewed.The advantages,limitations,challenges,and prospects of V/NIR spectroscopy and HSI for plant heavy metal stress phenotyping are discussed.Further studies are needed to promote the research and application of V/NIR spectroscopy and HSI for plant heavy metal stress phenotyping.
基金This study was supported by the Shenzhen Science and Technology Projects(CJGJZD20210408092401004)the National Natural Science Foundation of China(61705195).
文摘Herbicides and heavy metals are hazardous substances of environmental pollution,resulting in plant stress and harming humans and animals.Identification of stress types can help trace stress sources,manage plant growth,and improve stress-resistant breeding.In this research,hyperspectral imaging(HSI)and chlorophyll fluorescence imaging(Chl-FI)were adopted to identify the rice plants under two types of herbicide stresses(butachlor(DCA)and quinclorac(ELK))and two types of heavy metal stresses(cadmium(Cd)and copper(Cu)).
基金This research was supported by XPCC Science and Technol-ogy Projects of Key Areas(2020AB005).
文摘Rapid determination of chlorophyll content is significant for evaluating cotton’s nutritional and physiological status.Hyperspectral technology equipped with multivariate analysis methods has been widely used for chlorophyll content detection.However,the model developed on one batch or variety cannot produce the same effect for another due to variations,such as samples and measurement conditions.