Lithium (Li) metal is a promising anode for the next generation high-energy–density batteries. However, the growth of Li dendrites, low coulombic efficiency and dramatic volume change limit its development. Here, we ...Lithium (Li) metal is a promising anode for the next generation high-energy–density batteries. However, the growth of Li dendrites, low coulombic efficiency and dramatic volume change limit its development. Here, we report a new synthetic poly-dioxolane (PDOL) approach to constructing an artificial 'elastic' SEI to stabilize the Li/electrolyte interface and the Li deposition/dissolution behavior in a variety of electrolytes. By coating PDOL with optimized molecular weights and synthetic routes on Li metal anode, the 'elastic' SEI layer could be maintained on top of the Li metal anode to accommodate the Li deposition/dissolution. No dendrite formation was observed during the cycling process, and the interfacial side reactions were reduced significantly. Consequently, we successfully achieved 330 cycles with a CE of 98.4% in ether electrolytes and 90 cycles with a CE of 94.3% in carbonate electrolytes. Simultaneously, the Li-metal batteries with LiFePO_(4) as cathodes also exhibited improved cycling performance. This strategy could promote the development of dendrite-free metal anodes toward high-performance Li-metal batteries.展开更多
Cucumis hystrix Chakr.(2n=2x=24)is a wild species that can hybridize with cultivated cucumber(C.sativus L.,2n=2x=14),a globally important vegetable crop.However,cucumber breeding is hindered by its narrow genetic base...Cucumis hystrix Chakr.(2n=2x=24)is a wild species that can hybridize with cultivated cucumber(C.sativus L.,2n=2x=14),a globally important vegetable crop.However,cucumber breeding is hindered by its narrow genetic base.Therefore,introgression from C.hystrix has been anticipated to bring a breakthrough in cucumber improvement.Here,we report the chromosome-scale assembly of C.hystrix genome(289 Mb).Scaffold N50 reached 14.1 Mb.Over 90%of the sequences were anchored onto 12 chromosomes.A total of 23,864 genes were annotated using a hybrid method.Further,we conducted a comprehensive comparative genomic analysis of cucumber,C.hystrix,and melon(C.melo L.,2n=2x=24).Whole-genome comparisons revealed that C.hystrix is phylogenetically closer to cucumber than to melon,providing a molecular basis for the success of its hybridization with cucumber.Moreover,expanded gene families of C.hystrix were significantly enriched in“defense response,”and C.hystrix harbored 104 nucleotide-binding site-encoding disease resistance gene analogs.Furthermore,121 genes were positively selected,and 12(9.9%)of these were involved in responses to biotic stimuli,which might explain the high disease resistance of C.hystrix.The alignment of whole C.hystrix genome with cucumber genome and self-alignment revealed 45,417 chromosome-specific sequences evenly distributed on C.hystrix chromosomes.Finally,we developed four cucumber-C.hystrix alien addition lines and identified the exact introgressed chromosome using molecular and cytological methods.The assembled C.hystrix genome can serve as a valuable resource for studies on Cucumis evolution and interspecific introgression breeding of cucumber.展开更多
With the rapid increase of large-scale problems, the distribution of real-world datasets tends to be long-tailed. Existing solutions typically involve re-balancing strategies (i.e., re-sampling and re-weighting). Alth...With the rapid increase of large-scale problems, the distribution of real-world datasets tends to be long-tailed. Existing solutions typically involve re-balancing strategies (i.e., re-sampling and re-weighting). Although they can significantly promote the classifier learning of deep networks, they will unexpectedly impair the representative ability of the learned deep features to a certain extent. Therefore, this paper proposes a dual-channel learning algorithm with involution neural networks (DC-Invo) to take care of representation learning and classifier learning concurrently. In this work, the most important thing is to combine ResNet and involution to obtain higher classification accuracy because of involution’s wider coverage in the spatial dimension. The paper conducted extensive experiments on several benchmark vision tasks including Cifar-LT, Imagenet-LT, and Places-LT, showing that DC-Invo is able to achieve significant performance gained on long-tailed datasets.展开更多
近年来社会拥挤逐渐成为营销领域的一个研究热点,但仍较为零散,大量研究着重于探寻引起社会拥挤的原因等。消费行为往往受到微妙的环境因素的影响,随着拥挤状况在消费场所中日益频现,人们的消费倾向会发生改变,尤其在不同情境下,是否会...近年来社会拥挤逐渐成为营销领域的一个研究热点,但仍较为零散,大量研究着重于探寻引起社会拥挤的原因等。消费行为往往受到微妙的环境因素的影响,随着拥挤状况在消费场所中日益频现,人们的消费倾向会发生改变,尤其在不同情境下,是否会对消费群体的特殊消费行为产生影响尚未进行研究。鉴于此,本文针对社会拥挤,借助pajek针对web of science上核心论文进行网络分析,在现有研究成果的可视化基础,构建以食品与医疗行业为整体的研究框架,进行社会拥挤对放纵性消费的双情境实验对比研究。结果表明,餐饮情境下社会拥挤会显著降低放纵性消费水平,而在医疗情境下社会拥挤则会显著增加放纵性消费的水平,以期为学术研究和企业的营销管理提供参考和建议。展开更多
Global change has a significant impact on the lives of humankind.Earth observation can help to better understand our earth and cope with global change.With the availability of more reliable environmental data sets,dig...Global change has a significant impact on the lives of humankind.Earth observation can help to better understand our earth and cope with global change.With the availability of more reliable environmental data sets,digital earth is becoming a popular way to monitor the Earth and provide information to researchers and decision makers on environment protection,disaster mitigation,and social benefits.Therefore,accessing data with lowering costs is essential for digital earth.Nevertheless,there are big challenges in ensuring the feasibility of access to Chinese remote sensing data.This paper outlines some of the main challenges in realizing data sharing,provides an analysis of the core reasons leading to these challenges,and proposes recommendations to overcome the challenges.Amongst the main challenges are differences in data policy to gain access to satellite data,diverse data formats,and delivery mechanisms.The major challenge for the decision makers is to define a more open policy and for the scientist the challenge is to implement these polices for the benefit of all.This paper proposes that governments should adopt policies encouraging more open distribution and access to their data,in order to generate an improved digital earth with increased benefits to human society.展开更多
Asteroid exploration is significant for studying the origin of the solar system,establishing planetary defenses,and alleviating the resource crisis of the Earth.Asteroid anchoring is the basis of in-situ exploration a...Asteroid exploration is significant for studying the origin of the solar system,establishing planetary defenses,and alleviating the resource crisis of the Earth.Asteroid anchoring is the basis of in-situ exploration and resource development and utilization.Therefore,the performance of asteroid force-closure anchoring is investigated using the discrete element method.The micro parameters of the simulated materials are calibrated with angle of repose and uniaxial compression experiments,based on which the regional modeling method is adopted to establish the anchoring discrete element model.Asteroid anchoring experiments are conducted on a self-developed microgravity simulation platform to verify the accuracy of the simulation model.The asteroid anchoring simulations are performed to investigate the influence of external force on the anchoring performance.The analysis of anchoring force varying with time and the interaction between the anchor and regolith particles reveals the influence mechanism of external force direction on the anchoring performance.The external force direction affects the critical anchoring force by influencing the failure of the force-closure structure.The comprehensive analysis of simulation results clarifies the variation of the critical anchoring force with the external forces.Finally,a stable anchoring region is established,beneficial for asteroid anchoring device design.展开更多
Objective:To analyze the current situation of diagnostic radiology equipment in Chinese mainland and to understand changes in the past 20 years,including gaps with other countries,in order to provide a scientific basi...Objective:To analyze the current situation of diagnostic radiology equipment in Chinese mainland and to understand changes in the past 20 years,including gaps with other countries,in order to provide a scientific basis for the government to formulate relevant policies and regulations,and supplement Chinese data for international organizations.Methods:This survey adopted a uniformly designed questionnaire,which was completed by the investigators or the respondents.The survey was distributed to all medical institutions that provided diagnostic radiology services in 31 provinces,autonomous regions,and municipalities,excluding Hong Kong,Macao,Taiwan,and military,China.Results:The survey showed that in the past 20 years,the number of medical institutions and diagnostic radiology equipment per million population in China has increased substantially.Dental radiology equipment increased nine-fold,and mammography equipment and computed tomography scanners showed a nearly five-fold increase.The four types of diagnostic radiology equipment,general diagnostic,fluoroscopic,mammography,and computed tomography,were associated with the population.Dental radiology equipment and bone mineral densitometers were related only to the gross domestic product(GDP).A large gap remains in the diagnostic radiology equipment per million population between China and the equipment of health-care level(HCL)I countries.Conclusions:An imbalance in the number of units of diagnostic radiology equipment per million population was observed in the different regions,China.Various types of diagnostic radiology equipment,especially mammography equipment and computed tomography scanners,need to be deployed to meet the medical needs of different populations.展开更多
The compilation of global Landsat data-sets and the ever-lowering costs of computing now make it feasible to monitor the Earth’s land cover at Landsat resolutions of 30 m.In this article,we describe the methods to cr...The compilation of global Landsat data-sets and the ever-lowering costs of computing now make it feasible to monitor the Earth’s land cover at Landsat resolutions of 30 m.In this article,we describe the methods to create global products of forest cover and cover change at Landsat resolutions.Nevertheless,there are many challenges in ensuring the creation of high-quality products.And we propose various ways in which the challenges can be overcome.Among the challenges are the need for atmospheric correction,incorrect calibration coefficients in some of the data-sets,the different phenologies between compila-tions,the need for terrain correction,the lack of consistent reference data for training and accuracy assessment,and the need for highly automated character-ization and change detection.We propose and evaluate the creation and use of surface reflectance products,improved selection of scenes to reduce phenological differences,terrain illumination correction,automated training selection,and the use of information extraction procedures robust to errors in training data along with several other issues.At several stages we use Moderate Resolution Spectro-radiometer data and products to assist our analysis.A global working prototype product of forest cover and forest cover change is included.展开更多
Mg2+in MgAl-layered double hydroxides nanoparticles was substituted with different divalent transition metal ions(MAl-LDHs,M:Mg2+,Cu2+,Ni2+,Co2+,and Mn2+)via a facile method to be used as antibacterial agents.The phas...Mg2+in MgAl-layered double hydroxides nanoparticles was substituted with different divalent transition metal ions(MAl-LDHs,M:Mg2+,Cu2+,Ni2+,Co2+,and Mn2+)via a facile method to be used as antibacterial agents.The phase structural and morphological characterizations of MAl-LDHs were investigated by XRD,FTIR spectroscopy and TEM.The results have shown that all of MAl-LDHs had typical layered structures except MnAl-LDH which contained Mn304 phases.Particular morphology of MnAl-LDH with ellipsoids,spherical and rod-like structure and CuAl-LDH with rod-like shape existed.IC50(the concentrations providing 50%antibacterial activity)values of CuAl-LDH,NiAl-LDH,CoAl-LDH,and MnAlLDH in broth dilution tests were^800-1500μg/mL.Dosages of CuAl-LDH,CoAl-LDH,and MnAl-LDH with>10 mm inhibition zone in disk diffusion tests were^150-300μg/disk.Antibacterial mechanism of MAl-LDHs may be attributed to the synergistic factors including effected surroundings,surface interactions,morphology of particles,ROS and metal ions.The results indicate a facile method to synthesis LDHs based effective antibacterial agents with the potential application in the area of water treatment and antibacterial coating.展开更多
Long-term observation of the earth is essential for studying the factors affecting global environmental changes.Digital earth technology can facilitate the monitoring of global environmental change with its ability to...Long-term observation of the earth is essential for studying the factors affecting global environmental changes.Digital earth technology can facilitate the monitoring of global environmental change with its ability to process vast amounts of information.In this study,we map the forest cover change of Myanmar from 2000 to 2005 using a training data automation procedure and support vector machines algorithm.Our results show that Myanmar’s forests have declined 0.68%annually over this six-year period.We validated our derived change results and found the overall accuracy to be greater than 88%.We also assessed forest loss from protected areas,areas close to roads,and areas subject to fire,which were most likely to lose forested area.The results revealed the main reasons for forest losses in some hotspots to be increased agricultural conversion,fire,and the construction of highways.This information is useful for identifying the driving forces behind forest changes and to support environmental policy development in Myanmar.展开更多
基金This research was supported financially by the Major Program of the National Natural Science Foundation of China(21890731).
文摘Lithium (Li) metal is a promising anode for the next generation high-energy–density batteries. However, the growth of Li dendrites, low coulombic efficiency and dramatic volume change limit its development. Here, we report a new synthetic poly-dioxolane (PDOL) approach to constructing an artificial 'elastic' SEI to stabilize the Li/electrolyte interface and the Li deposition/dissolution behavior in a variety of electrolytes. By coating PDOL with optimized molecular weights and synthetic routes on Li metal anode, the 'elastic' SEI layer could be maintained on top of the Li metal anode to accommodate the Li deposition/dissolution. No dendrite formation was observed during the cycling process, and the interfacial side reactions were reduced significantly. Consequently, we successfully achieved 330 cycles with a CE of 98.4% in ether electrolytes and 90 cycles with a CE of 94.3% in carbonate electrolytes. Simultaneously, the Li-metal batteries with LiFePO_(4) as cathodes also exhibited improved cycling performance. This strategy could promote the development of dendrite-free metal anodes toward high-performance Li-metal batteries.
基金the National Key Research and Development Program of China(#2018YFD1000804)the National Natural Science Foundation of China(Key Program,#31430075)+3 种基金the Belt and Road innovation cooperation project(#BZ2019012)the National Key Research and Development Program of China(#2016YFD0100204-25)the Jiangsu Agricultural Innovation of New Cultivars(#PZCZ201719)by a project funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions.
文摘Cucumis hystrix Chakr.(2n=2x=24)is a wild species that can hybridize with cultivated cucumber(C.sativus L.,2n=2x=14),a globally important vegetable crop.However,cucumber breeding is hindered by its narrow genetic base.Therefore,introgression from C.hystrix has been anticipated to bring a breakthrough in cucumber improvement.Here,we report the chromosome-scale assembly of C.hystrix genome(289 Mb).Scaffold N50 reached 14.1 Mb.Over 90%of the sequences were anchored onto 12 chromosomes.A total of 23,864 genes were annotated using a hybrid method.Further,we conducted a comprehensive comparative genomic analysis of cucumber,C.hystrix,and melon(C.melo L.,2n=2x=24).Whole-genome comparisons revealed that C.hystrix is phylogenetically closer to cucumber than to melon,providing a molecular basis for the success of its hybridization with cucumber.Moreover,expanded gene families of C.hystrix were significantly enriched in“defense response,”and C.hystrix harbored 104 nucleotide-binding site-encoding disease resistance gene analogs.Furthermore,121 genes were positively selected,and 12(9.9%)of these were involved in responses to biotic stimuli,which might explain the high disease resistance of C.hystrix.The alignment of whole C.hystrix genome with cucumber genome and self-alignment revealed 45,417 chromosome-specific sequences evenly distributed on C.hystrix chromosomes.Finally,we developed four cucumber-C.hystrix alien addition lines and identified the exact introgressed chromosome using molecular and cytological methods.The assembled C.hystrix genome can serve as a valuable resource for studies on Cucumis evolution and interspecific introgression breeding of cucumber.
文摘With the rapid increase of large-scale problems, the distribution of real-world datasets tends to be long-tailed. Existing solutions typically involve re-balancing strategies (i.e., re-sampling and re-weighting). Although they can significantly promote the classifier learning of deep networks, they will unexpectedly impair the representative ability of the learned deep features to a certain extent. Therefore, this paper proposes a dual-channel learning algorithm with involution neural networks (DC-Invo) to take care of representation learning and classifier learning concurrently. In this work, the most important thing is to combine ResNet and involution to obtain higher classification accuracy because of involution’s wider coverage in the spatial dimension. The paper conducted extensive experiments on several benchmark vision tasks including Cifar-LT, Imagenet-LT, and Places-LT, showing that DC-Invo is able to achieve significant performance gained on long-tailed datasets.
文摘近年来社会拥挤逐渐成为营销领域的一个研究热点,但仍较为零散,大量研究着重于探寻引起社会拥挤的原因等。消费行为往往受到微妙的环境因素的影响,随着拥挤状况在消费场所中日益频现,人们的消费倾向会发生改变,尤其在不同情境下,是否会对消费群体的特殊消费行为产生影响尚未进行研究。鉴于此,本文针对社会拥挤,借助pajek针对web of science上核心论文进行网络分析,在现有研究成果的可视化基础,构建以食品与医疗行业为整体的研究框架,进行社会拥挤对放纵性消费的双情境实验对比研究。结果表明,餐饮情境下社会拥挤会显著降低放纵性消费水平,而在医疗情境下社会拥挤则会显著增加放纵性消费的水平,以期为学术研究和企业的营销管理提供参考和建议。
文摘Global change has a significant impact on the lives of humankind.Earth observation can help to better understand our earth and cope with global change.With the availability of more reliable environmental data sets,digital earth is becoming a popular way to monitor the Earth and provide information to researchers and decision makers on environment protection,disaster mitigation,and social benefits.Therefore,accessing data with lowering costs is essential for digital earth.Nevertheless,there are big challenges in ensuring the feasibility of access to Chinese remote sensing data.This paper outlines some of the main challenges in realizing data sharing,provides an analysis of the core reasons leading to these challenges,and proposes recommendations to overcome the challenges.Amongst the main challenges are differences in data policy to gain access to satellite data,diverse data formats,and delivery mechanisms.The major challenge for the decision makers is to define a more open policy and for the scientist the challenge is to implement these polices for the benefit of all.This paper proposes that governments should adopt policies encouraging more open distribution and access to their data,in order to generate an improved digital earth with increased benefits to human society.
基金co-supported by the National Natural Science Foundation of China(Nos.52105012,51975139 and 52111530038)Support by Self-Planned Task of State Key Laboratory of Robotics and System(No.SKLRS202101C).
文摘Asteroid exploration is significant for studying the origin of the solar system,establishing planetary defenses,and alleviating the resource crisis of the Earth.Asteroid anchoring is the basis of in-situ exploration and resource development and utilization.Therefore,the performance of asteroid force-closure anchoring is investigated using the discrete element method.The micro parameters of the simulated materials are calibrated with angle of repose and uniaxial compression experiments,based on which the regional modeling method is adopted to establish the anchoring discrete element model.Asteroid anchoring experiments are conducted on a self-developed microgravity simulation platform to verify the accuracy of the simulation model.The asteroid anchoring simulations are performed to investigate the influence of external force on the anchoring performance.The analysis of anchoring force varying with time and the interaction between the anchor and regolith particles reveals the influence mechanism of external force direction on the anchoring performance.The external force direction affects the critical anchoring force by influencing the failure of the force-closure structure.The comprehensive analysis of simulation results clarifies the variation of the critical anchoring force with the external forces.Finally,a stable anchoring region is established,beneficial for asteroid anchoring device design.
文摘Objective:To analyze the current situation of diagnostic radiology equipment in Chinese mainland and to understand changes in the past 20 years,including gaps with other countries,in order to provide a scientific basis for the government to formulate relevant policies and regulations,and supplement Chinese data for international organizations.Methods:This survey adopted a uniformly designed questionnaire,which was completed by the investigators or the respondents.The survey was distributed to all medical institutions that provided diagnostic radiology services in 31 provinces,autonomous regions,and municipalities,excluding Hong Kong,Macao,Taiwan,and military,China.Results:The survey showed that in the past 20 years,the number of medical institutions and diagnostic radiology equipment per million population in China has increased substantially.Dental radiology equipment increased nine-fold,and mammography equipment and computed tomography scanners showed a nearly five-fold increase.The four types of diagnostic radiology equipment,general diagnostic,fluoroscopic,mammography,and computed tomography,were associated with the population.Dental radiology equipment and bone mineral densitometers were related only to the gross domestic product(GDP).A large gap remains in the diagnostic radiology equipment per million population between China and the equipment of health-care level(HCL)I countries.Conclusions:An imbalance in the number of units of diagnostic radiology equipment per million population was observed in the different regions,China.Various types of diagnostic radiology equipment,especially mammography equipment and computed tomography scanners,need to be deployed to meet the medical needs of different populations.
基金support from the NASATerrestrial Ecology Program which led to the creation of LEDAPS on which much of this work is based.We acknowledge the help of two people in particular from USGS EROS:Gyanesh Chander helped to identify the GLS 1990 images that have most recent USGS calibration coefficients(?50%of the GLS 1990 data-set).Rachel Headley helped us obtain the GLS data-sets.She also helped significantly with our reordering of the GLS 1990 images that had good calibration coefficients。
文摘The compilation of global Landsat data-sets and the ever-lowering costs of computing now make it feasible to monitor the Earth’s land cover at Landsat resolutions of 30 m.In this article,we describe the methods to create global products of forest cover and cover change at Landsat resolutions.Nevertheless,there are many challenges in ensuring the creation of high-quality products.And we propose various ways in which the challenges can be overcome.Among the challenges are the need for atmospheric correction,incorrect calibration coefficients in some of the data-sets,the different phenologies between compila-tions,the need for terrain correction,the lack of consistent reference data for training and accuracy assessment,and the need for highly automated character-ization and change detection.We propose and evaluate the creation and use of surface reflectance products,improved selection of scenes to reduce phenological differences,terrain illumination correction,automated training selection,and the use of information extraction procedures robust to errors in training data along with several other issues.At several stages we use Moderate Resolution Spectro-radiometer data and products to assist our analysis.A global working prototype product of forest cover and forest cover change is included.
基金financially supported by Advance Queensland Research Fellowship Project and Chinese Scholarship Council(CSC)。
文摘Mg2+in MgAl-layered double hydroxides nanoparticles was substituted with different divalent transition metal ions(MAl-LDHs,M:Mg2+,Cu2+,Ni2+,Co2+,and Mn2+)via a facile method to be used as antibacterial agents.The phase structural and morphological characterizations of MAl-LDHs were investigated by XRD,FTIR spectroscopy and TEM.The results have shown that all of MAl-LDHs had typical layered structures except MnAl-LDH which contained Mn304 phases.Particular morphology of MnAl-LDH with ellipsoids,spherical and rod-like structure and CuAl-LDH with rod-like shape existed.IC50(the concentrations providing 50%antibacterial activity)values of CuAl-LDH,NiAl-LDH,CoAl-LDH,and MnAlLDH in broth dilution tests were^800-1500μg/mL.Dosages of CuAl-LDH,CoAl-LDH,and MnAl-LDH with>10 mm inhibition zone in disk diffusion tests were^150-300μg/disk.Antibacterial mechanism of MAl-LDHs may be attributed to the synergistic factors including effected surroundings,surface interactions,morphology of particles,ROS and metal ions.The results indicate a facile method to synthesis LDHs based effective antibacterial agents with the potential application in the area of water treatment and antibacterial coating.
文摘Long-term observation of the earth is essential for studying the factors affecting global environmental changes.Digital earth technology can facilitate the monitoring of global environmental change with its ability to process vast amounts of information.In this study,we map the forest cover change of Myanmar from 2000 to 2005 using a training data automation procedure and support vector machines algorithm.Our results show that Myanmar’s forests have declined 0.68%annually over this six-year period.We validated our derived change results and found the overall accuracy to be greater than 88%.We also assessed forest loss from protected areas,areas close to roads,and areas subject to fire,which were most likely to lose forested area.The results revealed the main reasons for forest losses in some hotspots to be increased agricultural conversion,fire,and the construction of highways.This information is useful for identifying the driving forces behind forest changes and to support environmental policy development in Myanmar.
