Lilium nepalense D. Don is an ornamental plant and exhibits high morphological variation across its distribution range in China. There is incongruence between different data sets for the status of it in Lilium. In thi...Lilium nepalense D. Don is an ornamental plant and exhibits high morphological variation across its distribution range in China. There is incongruence between different data sets for the status of it in Lilium. In this study, we reported a complete chloroplast genome of L. nepalense sampled in Hengduan Mountains, China. The whole chloroplast genome possessed a total length of 152,206 bp with typical circular structure, and contained a large single copy (LSC) of 81,854 bp and a small single copy (SSC) of 17,563 bp, which were separated by a pair of inverted repeats (IRa/IRb) of 26,399 bp. The average GC content among the whole chloroplast genome sequence was 37%, and the GC content in LSC, SSC, IRs regions were 34.8%, 30.6%, and 42.5%, respectively. There were 135 genes detected from the whole chloroplast genome sequence, including 89 protein-coding genes, 38 tRNAs, and 8 rRNAs. Phylogenetic results using maximum likelihood and Bayesian methods showed congruent results that L. nepalense together with the other two L. nepalense samples collected from different habitats formed a single branch, indicating a close relationship of L. nepalense with L. taliense belonging to the section Sinomartagon. This newly characterized chloroplast genome will provide essential data for the further population genetics research of L. nepalense.展开更多
Cellular material under high-velocity impacthas a typical feature oflayer-wise collapse.A cell-based finite element model is employed to simulate the direct impact of closed-cell foam, and one-dimensional velocity fie...Cellular material under high-velocity impacthas a typical feature oflayer-wise collapse.A cell-based finite element model is employed to simulate the direct impact of closed-cell foam, and one-dimensional velocity field distributionsareobtained to characterize thecrushing bandpropagating through a cellular material. An explicit expression of continuous velocity distribution is derivedbased on the features of velocity gradient distribution. The velocity distribution function is adopted to determine the dynamic stress-strain statesof cellular materials under dynamic loading.The local stress-strain history distribution reveals that sectional cells experience a process from the precursor of elastic behavior to the shock stress state, through the dynamic initial crushing state. A power-law relation between the dynamic initial crushing stress andthe strainrate isestablished, which confirms the strain-rate effect of cellular materials. By extracting the critical points immediately before the unloading stage on the local dynamic stress-strain history curves, the dynamic stress-strain statesof cellular materials are determined. They exhibit loading rate-dependence but are independent of the initial impact velocity.Furthermore, with the increase of relative density, the dynamic hardening behaviorof cellular specimen is enhanced and the crushing process event is advanced. The particle velocity-based analytical method is appliedto analyze the dynamic responses of cellular materials.This method is better than continuum-based shock models, since itdoes not require a pre-assumed constitutive relation.Therefore,the particle velocity-based analytical method proposed in this study may provide new ideas to carry out dynamic experimental measurement, which is especially applicable toinhomogeneous materials.展开更多
Since 2014, Zibo Plant Protection Station has carried out a series of prevention and control tests in the city to solve the problem of increasingly aggravated root and stem diseases of wheat. According to the results ...Since 2014, Zibo Plant Protection Station has carried out a series of prevention and control tests in the city to solve the problem of increasingly aggravated root and stem diseases of wheat. According to the results of individual test, the technical procedures for integrated management of wheat sheath blight and wheat crown rot based on deep tillage, seed coating and chemical control in spring are integrated. The technique has been greatly promoted through on-site meetings, training and publicity, demonstration and promotion, unified prevention and control, and green prevention and control, which increases wheat yield in technology application area, reduces the use of chemical pesticides, and protects the ecological environment. The radiation drives increasing production and incomes of the surrounding farmers, receiving remarkable economic, social and ecological benefits.展开更多
A virtual Taylor impact of cellular materials is analyzed with a wave propagation technique, i.e. the Lagrangian analysis method, of which the main advantage is that no pre-assumed constitutive relationship is require...A virtual Taylor impact of cellular materials is analyzed with a wave propagation technique, i.e. the Lagrangian analysis method, of which the main advantage is that no pre-assumed constitutive relationship is required. Time histories of particle velocity, local strain, and stress profiles are calculated to present the local stress-strain history curves, from which the dynamic stress-strain states are obtained. The present results reveal that the dynamic-rigid-plastic hardening (D-R-PH) material model introduced in a previous study of our group is in good agreement with the dynamic stress-strain states under high loading rates obtained by the Lagrangian analysis method. It directly reflects the effectiveness and feasibility of the D-R-PH material model for the cellular materials under high loading rates.展开更多
The supercritical circulating fluidized bed(CFB)boiler,which combines the advantages of CFB combustion with low cost emission control and supercritical steam cycle with high efficiency of coal energy,is believed to be...The supercritical circulating fluidized bed(CFB)boiler,which combines the advantages of CFB combustion with low cost emission control and supercritical steam cycle with high efficiency of coal energy,is believed to be the future of CFB combustion technology.It is also of greatest importance for low rank coal utilization in China.Different from the supercritical pulverized coal boiler that has been developed more than 50 years,the supercritical CFB boiler is still a new one which requires further investigation.Without any precedentor engineering reference,Chinese researchers have con ducted fundamental research,development,design of the supercritical CFB boilers independently.The design theory and key technology for supercritical CFB boiler were proposed.Key components and novel structures were invented.The first 600 MWe supercritical CFB boiler and its auxiliaries were successfully developed and demonstrated in Baima Power Plant,Shenhua Group as well as the simulator,control technology,installation technology,commissioning technology,system integration and operation technology.Compared with the 460 MWe supercritical CFB in Poland,developed in the same period and the only other supercritical one of commercial running in the word beside Baima,the 600 MWe one in Baima has a better performance.Besides,supercritical CFB boilers of 350 MWe have been developed and widely commercialized in China.In this paper,the updated progress of 660 MWe ultra-supercritical CFB boilers under development is introduced.展开更多
The scientific application of stabilized materials has been considered an effective method for the in situ remediation of Cd-contaminated soil.This study aimed to investigate the persistence of the effect of a combine...The scientific application of stabilized materials has been considered an effective method for the in situ remediation of Cd-contaminated soil.This study aimed to investigate the persistence of the effect of a combined amendment of limestone and sepiolite(LS)on soil Cd availability and accumulation in rice grown in a mildly Cd-contaminated paddy field(0.45 mg/kg of Cd)over three consecutive rice seasons.1125–4500 kg/ha of LS was applied to the soil before the first rice planting season and 562.5–2250 kg/ha of LS was supplemented before the third rice planting season.The application of LS(1125–4500 kg/ha)increased the soil p H by 0.44–1.09,0.18–0.53,and 0.42–0.68 in the first,second,and third season,respectively,and decreased the soil acid-extractable Cd content by 18.2–36.4%,17.7–33.5%,and9.6–17.6%.LS application significantly decreased the Cd contents in the rice tissues.The application of 4500 kg/ha of LS decreased the Cd content in brown rice to below the National Food Limit Standard of 0.2 mg/kg(GB 2762-2017)in the three consecutive rice seasons.However,the effect of LS on the soil-rice system was significantly weakened in the third season.The supplementary application of 562.5–2250 kg/ha of LS further decreased the Cd content in brown rice by 26.1–56.5%and decreased the health risk index by 23.7–43.8%.Therefore,it was recommended to apply 4500 kg/ha of LS in the first season and to supplement2250 kg/ha of LS in the third season to effectively guarantee the clean production of rice in three consecutive rice seasons.展开更多
With the characteristic of flexible and precise,unmanned aerial vehicles(UAVs)for low volume applications are increasing substantially and quickly around the globe.However,little attention has been paid to the study o...With the characteristic of flexible and precise,unmanned aerial vehicles(UAVs)for low volume applications are increasing substantially and quickly around the globe.However,little attention has been paid to the study of wheat herbicides with UAV,especially the research on the spray volume and droplet size of the herbicide sprayed by UAVs.The objectives of this study were to compare the droplet deposition from a typical commercial UAV under four different spray volumes of 7.5 L/hm2,15.0 L/hm2,22.5 L/hm2,and 30.0 L/hm2 and three different volume median diameter(VMD)of 150μm,200μm,and 300μm during winter wheat weeding period.DepositScan software was used to analyze droplet deposition parameters including the percentage of spray coverage and the number of droplets in various sampling positions.The test results showed that the droplet deposition waseffected by each factor andtheirinteractions.When the spray volume was 7.5 L/hm2,the effect of VMD on the percentage of spray coverage was not significant.However,these variation rules were changed to smaller droplets with greater coverage when the spray volume higher than 15.0 L/hm2.In all treatments,the number of droplets increased with decreasing VMD or increasing spray volume.The maximum percentage of spray coverage and the number of droplets that were achieved under the VMD of 150μm and the spray volume of 30.0 L/hm2 were 12.8%and 40.0 droplets/cm2,respectively.The variation coefficients of the percentage of spray coverage and the number of droplets were 29.0%-73.3%and 20.2%-54.1%,respectively.The most uniform deposition was achieved under the spray volume of 15.0 L/hm2and the VMD of 150μm.The results revealed the effect of droplet size and spray volume parameters on droplet deposition,which was useful for guiding farmers on how to use UAVs for weeding in winter wheat fields.展开更多
As a typical compression member,the concrete-filled steel tube has been widely used in civil engineering structures.However,little research on recycled self-compacting concrete flled circular steel tubular(RSCCFCST)co...As a typical compression member,the concrete-filled steel tube has been widely used in civil engineering structures.However,little research on recycled self-compacting concrete flled circular steel tubular(RSCCFCST)columns subjected to eccentric load was reported.In this study,21 specimens were designed and experimental studies on the stress-strain relationship of were carried out to study the mechanical behaviors.Recycled coarse aggregate replacement ratio,concrete strength grade,length to diameter ratio and eccentric distance of specimens were considered as the main experimental parameters to carry out eccentric compression tests.The corresponding stress-strain relationship curves were used to analyze the influence of concerned parameters on ecentric load-bearing capacity of RSCCFCST columns.The experimental results show that the strain of the eccentric compression stress-strain curves increase with the increase of recycled coarse aggregate replacement ratio and concrete strength grade.With increase of eccentric distance,the ductility of specimens increases while the bearing capacity decreases.Moreover,a phenomenological model of RSCCFCST columns is proposed,which exhibits versatile ability to capture the process during loading.The present study is expected to further understanding the behaviors and to provide guidance of RSCCFCST columns in design and engineering applications.展开更多
文摘Lilium nepalense D. Don is an ornamental plant and exhibits high morphological variation across its distribution range in China. There is incongruence between different data sets for the status of it in Lilium. In this study, we reported a complete chloroplast genome of L. nepalense sampled in Hengduan Mountains, China. The whole chloroplast genome possessed a total length of 152,206 bp with typical circular structure, and contained a large single copy (LSC) of 81,854 bp and a small single copy (SSC) of 17,563 bp, which were separated by a pair of inverted repeats (IRa/IRb) of 26,399 bp. The average GC content among the whole chloroplast genome sequence was 37%, and the GC content in LSC, SSC, IRs regions were 34.8%, 30.6%, and 42.5%, respectively. There were 135 genes detected from the whole chloroplast genome sequence, including 89 protein-coding genes, 38 tRNAs, and 8 rRNAs. Phylogenetic results using maximum likelihood and Bayesian methods showed congruent results that L. nepalense together with the other two L. nepalense samples collected from different habitats formed a single branch, indicating a close relationship of L. nepalense with L. taliense belonging to the section Sinomartagon. This newly characterized chloroplast genome will provide essential data for the further population genetics research of L. nepalense.
基金This work was supported by the National Natural Science Foundation of China (Grants 11802002, 11772330, and 11372308)the Fundamental Research Funds for the Central Universities (Grant WK2480000003)the Youth Foundation of Anhui University of Technology (Grant RD 17100204).
文摘Cellular material under high-velocity impacthas a typical feature oflayer-wise collapse.A cell-based finite element model is employed to simulate the direct impact of closed-cell foam, and one-dimensional velocity field distributionsareobtained to characterize thecrushing bandpropagating through a cellular material. An explicit expression of continuous velocity distribution is derivedbased on the features of velocity gradient distribution. The velocity distribution function is adopted to determine the dynamic stress-strain statesof cellular materials under dynamic loading.The local stress-strain history distribution reveals that sectional cells experience a process from the precursor of elastic behavior to the shock stress state, through the dynamic initial crushing state. A power-law relation between the dynamic initial crushing stress andthe strainrate isestablished, which confirms the strain-rate effect of cellular materials. By extracting the critical points immediately before the unloading stage on the local dynamic stress-strain history curves, the dynamic stress-strain statesof cellular materials are determined. They exhibit loading rate-dependence but are independent of the initial impact velocity.Furthermore, with the increase of relative density, the dynamic hardening behaviorof cellular specimen is enhanced and the crushing process event is advanced. The particle velocity-based analytical method is appliedto analyze the dynamic responses of cellular materials.This method is better than continuum-based shock models, since itdoes not require a pre-assumed constitutive relation.Therefore,the particle velocity-based analytical method proposed in this study may provide new ideas to carry out dynamic experimental measurement, which is especially applicable toinhomogeneous materials.
文摘Since 2014, Zibo Plant Protection Station has carried out a series of prevention and control tests in the city to solve the problem of increasingly aggravated root and stem diseases of wheat. According to the results of individual test, the technical procedures for integrated management of wheat sheath blight and wheat crown rot based on deep tillage, seed coating and chemical control in spring are integrated. The technique has been greatly promoted through on-site meetings, training and publicity, demonstration and promotion, unified prevention and control, and green prevention and control, which increases wheat yield in technology application area, reduces the use of chemical pesticides, and protects the ecological environment. The radiation drives increasing production and incomes of the surrounding farmers, receiving remarkable economic, social and ecological benefits.
基金supported by the National Natural Science Foundation of China(11372308 and 11372307)the Fundamental Research Funds for the Central Universities(WK2480000001)
文摘A virtual Taylor impact of cellular materials is analyzed with a wave propagation technique, i.e. the Lagrangian analysis method, of which the main advantage is that no pre-assumed constitutive relationship is required. Time histories of particle velocity, local strain, and stress profiles are calculated to present the local stress-strain history curves, from which the dynamic stress-strain states are obtained. The present results reveal that the dynamic-rigid-plastic hardening (D-R-PH) material model introduced in a previous study of our group is in good agreement with the dynamic stress-strain states under high loading rates obtained by the Lagrangian analysis method. It directly reflects the effectiveness and feasibility of the D-R-PH material model for the cellular materials under high loading rates.
文摘The supercritical circulating fluidized bed(CFB)boiler,which combines the advantages of CFB combustion with low cost emission control and supercritical steam cycle with high efficiency of coal energy,is believed to be the future of CFB combustion technology.It is also of greatest importance for low rank coal utilization in China.Different from the supercritical pulverized coal boiler that has been developed more than 50 years,the supercritical CFB boiler is still a new one which requires further investigation.Without any precedentor engineering reference,Chinese researchers have con ducted fundamental research,development,design of the supercritical CFB boilers independently.The design theory and key technology for supercritical CFB boiler were proposed.Key components and novel structures were invented.The first 600 MWe supercritical CFB boiler and its auxiliaries were successfully developed and demonstrated in Baima Power Plant,Shenhua Group as well as the simulator,control technology,installation technology,commissioning technology,system integration and operation technology.Compared with the 460 MWe supercritical CFB in Poland,developed in the same period and the only other supercritical one of commercial running in the word beside Baima,the 600 MWe one in Baima has a better performance.Besides,supercritical CFB boilers of 350 MWe have been developed and widely commercialized in China.In this paper,the updated progress of 660 MWe ultra-supercritical CFB boilers under development is introduced.
基金supported by the National Natural Science Foundation of China(No.41907126)the Natural Science Foundation of Hunan Province,China(Nos.2018JJ3880,2018JJ3881)the Changsha Science and Technology Project(No.kq1901138)。
文摘The scientific application of stabilized materials has been considered an effective method for the in situ remediation of Cd-contaminated soil.This study aimed to investigate the persistence of the effect of a combined amendment of limestone and sepiolite(LS)on soil Cd availability and accumulation in rice grown in a mildly Cd-contaminated paddy field(0.45 mg/kg of Cd)over three consecutive rice seasons.1125–4500 kg/ha of LS was applied to the soil before the first rice planting season and 562.5–2250 kg/ha of LS was supplemented before the third rice planting season.The application of LS(1125–4500 kg/ha)increased the soil p H by 0.44–1.09,0.18–0.53,and 0.42–0.68 in the first,second,and third season,respectively,and decreased the soil acid-extractable Cd content by 18.2–36.4%,17.7–33.5%,and9.6–17.6%.LS application significantly decreased the Cd contents in the rice tissues.The application of 4500 kg/ha of LS decreased the Cd content in brown rice to below the National Food Limit Standard of 0.2 mg/kg(GB 2762-2017)in the three consecutive rice seasons.However,the effect of LS on the soil-rice system was significantly weakened in the third season.The supplementary application of 562.5–2250 kg/ha of LS further decreased the Cd content in brown rice by 26.1–56.5%and decreased the health risk index by 23.7–43.8%.Therefore,it was recommended to apply 4500 kg/ha of LS in the first season and to supplement2250 kg/ha of LS in the third season to effectively guarantee the clean production of rice in three consecutive rice seasons.
基金The authors acknowledge that this work was financially supported by the Leading Talents of Top Talents Program for One Case One Discussion of Shandong Provincethe Development Special Funds on Science and Technology to Guide Local by the Central Government:“Research and Development on Technology and Equipment of Precision Agriculture Aviation”+4 种基金Science and Technology Development Program of Zibo(Grant No.2018kj010073)Program of Shandong Provincial Collaborative Innovation Center of Dry-farming Intelligent Agricultural EquipmentYoung Innovative Talents Project of Regular Institutions of Higher Education of Guangdong Province(Grant No.2018KQNCX020)Key Science and Technology Plan of Guangdong Province(Grant No.2017B010116003)The authors acknowledge Corteva Agroscience Technology(Shanghai)Co.,Ltd for providing corresponding materials,and also thank reviewers and editors for giving relevant revision advice to improve the paper.
文摘With the characteristic of flexible and precise,unmanned aerial vehicles(UAVs)for low volume applications are increasing substantially and quickly around the globe.However,little attention has been paid to the study of wheat herbicides with UAV,especially the research on the spray volume and droplet size of the herbicide sprayed by UAVs.The objectives of this study were to compare the droplet deposition from a typical commercial UAV under four different spray volumes of 7.5 L/hm2,15.0 L/hm2,22.5 L/hm2,and 30.0 L/hm2 and three different volume median diameter(VMD)of 150μm,200μm,and 300μm during winter wheat weeding period.DepositScan software was used to analyze droplet deposition parameters including the percentage of spray coverage and the number of droplets in various sampling positions.The test results showed that the droplet deposition waseffected by each factor andtheirinteractions.When the spray volume was 7.5 L/hm2,the effect of VMD on the percentage of spray coverage was not significant.However,these variation rules were changed to smaller droplets with greater coverage when the spray volume higher than 15.0 L/hm2.In all treatments,the number of droplets increased with decreasing VMD or increasing spray volume.The maximum percentage of spray coverage and the number of droplets that were achieved under the VMD of 150μm and the spray volume of 30.0 L/hm2 were 12.8%and 40.0 droplets/cm2,respectively.The variation coefficients of the percentage of spray coverage and the number of droplets were 29.0%-73.3%and 20.2%-54.1%,respectively.The most uniform deposition was achieved under the spray volume of 15.0 L/hm2and the VMD of 150μm.The results revealed the effect of droplet size and spray volume parameters on droplet deposition,which was useful for guiding farmers on how to use UAVs for weeding in winter wheat fields.
基金Supported by the National Natural Science Foundation of China(Grant Nos.51578001,51608003,and 51878002)Natural Science Foundation granted by Department of Education,Anhui Province(No.KJ2015ZD10)+2 种基金Key Research and Development Plan of Anhui Province(No.1704a0802131)the Outstanding Young Talent Support Program of Anhui Province(No.gxyqZD2016072)This work was also supported by the Graduate Innovation Research Foundation granted by Anhui University of Technology(Nos.2016097,2016094).
文摘As a typical compression member,the concrete-filled steel tube has been widely used in civil engineering structures.However,little research on recycled self-compacting concrete flled circular steel tubular(RSCCFCST)columns subjected to eccentric load was reported.In this study,21 specimens were designed and experimental studies on the stress-strain relationship of were carried out to study the mechanical behaviors.Recycled coarse aggregate replacement ratio,concrete strength grade,length to diameter ratio and eccentric distance of specimens were considered as the main experimental parameters to carry out eccentric compression tests.The corresponding stress-strain relationship curves were used to analyze the influence of concerned parameters on ecentric load-bearing capacity of RSCCFCST columns.The experimental results show that the strain of the eccentric compression stress-strain curves increase with the increase of recycled coarse aggregate replacement ratio and concrete strength grade.With increase of eccentric distance,the ductility of specimens increases while the bearing capacity decreases.Moreover,a phenomenological model of RSCCFCST columns is proposed,which exhibits versatile ability to capture the process during loading.The present study is expected to further understanding the behaviors and to provide guidance of RSCCFCST columns in design and engineering applications.