The significant impact of earthquakes on human lives and the built environment underscores the extensive human and economic losses caused by structural collapses. Over the years, researchers have focused on improving ...The significant impact of earthquakes on human lives and the built environment underscores the extensive human and economic losses caused by structural collapses. Over the years, researchers have focused on improving seismic design to mitigate earthquake-induced damages and enhance structural performance. In this study, a specific reinforced concrete (RC) frame structure at Kyungpook National University, designed for educational purposes, is analyzed as a representative case. Utilizing SAP 2000, the research conducts a nonlinear time history analysis to assess the structural performance under seismic conditions. The primary objective is to evaluate the influence of different column section designs, while maintaining identical column section areas, on structural behavior. The study employs two distinct seismic waves from Abeno (ABN) and Takatori (TKT) for the analysis, comparing the structural performance under varying seismic conditions. Key aspects examined include displacement, base shear force, base moment, joint radians, and layer displacement angle. This research is anticipated to serve as a valuable reference for seismic restraint reinforcement work on RC buildings, enriching the methods used for evaluating structures through nonlinear time history analysis based on the synthetic seismic wave approach.展开更多
In contemporary society, reducing carbon dioxide emissions and achieving sustainable development are paramount goals. One effective approach is to preserve existing RC (Reinforced Concrete) buildings rather than demol...In contemporary society, reducing carbon dioxide emissions and achieving sustainable development are paramount goals. One effective approach is to preserve existing RC (Reinforced Concrete) buildings rather than demolishing them for new construction. However, a significant challenge arises from the lack of elevator designs in many of these existing RC buildings. Adding an external elevator becomes crucial to solving accessibility issues, enhancing property value, and satisfying modern residential buildings using convenient requirements. However, the structural performance of external elevator wells remains understudied. This research is designed by the actual external elevator project into existing RC buildings in Jinzhong Rd, Shanghai City. Specifically, this research examines five different external elevator wells under nonlinear pushover analysis, each varying in the height of the RC (Reinforced Concrete) footing. By analyzing plastic hinge states, performance points, capacity curves, spectrum curves, layer displacement, and drift ratio, this research aims to provide a comprehensive understanding of how these structures of the external elevator well respond to seismic events. The findings are expected to serve as a valuable reference for future external elevator projects, ensuring the external elevator designs meet the seismic requirements. By emphasizing seismic resistance in the design phase, the research aims to enhance the overall safety and longevity of external elevator systems integrated into existing RC buildings.展开更多
Elevators are essential components of contemporary buildings, enabling efficient vertical mobility for occupants. However, the proliferation of tall buildings has exacerbated challenges such as traffic congestion with...Elevators are essential components of contemporary buildings, enabling efficient vertical mobility for occupants. However, the proliferation of tall buildings has exacerbated challenges such as traffic congestion within elevator systems. Many passengers experience dissatisfaction with prolonged wait times, leading to impatience and frustration among building occupants. The widespread adoption of neural networks and deep learning technologies across various fields and industries represents a significant paradigm shift, and unlocking new avenues for innovation and advancement. These cutting-edge technologies offer unprecedented opportunities to address complex challenges and optimize processes in diverse domains. In this study, LSTM (Long Short-Term Memory) network technology is leveraged to analyze elevator traffic flow within a typical office building. By harnessing the predictive capabilities of LSTM, the research aims to contribute to advancements in elevator group control design, ultimately enhancing the functionality and efficiency of vertical transportation systems in built environments. The findings of this research have the potential to reference the development of intelligent elevator management systems, capable of dynamically adapting to fluctuating passenger demand and optimizing elevator usage in real-time. By enhancing the efficiency and functionality of vertical transportation systems, the research contributes to creating more sustainable, accessible, and user-friendly living environments for individuals across diverse demographics.展开更多
This paper studies the time-fractional Korteweg-de Vries (KdV) equations with Caputo-Fabrizio fractional derivatives. The scheme is presented by using a finite difference method in temporal variable and a local discon...This paper studies the time-fractional Korteweg-de Vries (KdV) equations with Caputo-Fabrizio fractional derivatives. The scheme is presented by using a finite difference method in temporal variable and a local discontinuous Galerkin method (LDG) in space. Stability and convergence are demonstrated by a specific choice of numerical fluxes. Finally, the efficiency and accuracy of the scheme are verified by numerical experiments.展开更多
High ionic conductivity and superior interfacial stability of solid electrolytes at the electrodes are crucial factors for high-performance all-solid-state sodium batteries. Herein, a composite solid electrolyte Na3PS...High ionic conductivity and superior interfacial stability of solid electrolytes at the electrodes are crucial factors for high-performance all-solid-state sodium batteries. Herein, a composite solid electrolyte Na3PS4-polyethylene oxide is synthesized by the solution-phase reaction method with an improved ionic conductivity up to 9.4 × 10-5 S/cm at room temperature. Moreover, polyethylene oxide polymer layer is wrapped homogeneously on the surface of Na3PS4 particles, which could effectively avoid the direct contact between Na3PS4 electrolyte and sodium metal, thus alleviate their side reactions. We demonstrate that all-solid-state battery SnS2/Na with the composite solid electrolyte Na3PS4-polyethylene oxide delivers an enhanced electrochemical performance with 230 m Ah/g after 40 cycles.展开更多
The complex composition of herbal metabolites necessitates the development of powerful analytical techniques aimed to identify the bioactive components.The seeds of Descurainia sophia(SDS)are utilized in China as a co...The complex composition of herbal metabolites necessitates the development of powerful analytical techniques aimed to identify the bioactive components.The seeds of Descurainia sophia(SDS)are utilized in China as a cough and asthma relieving agent.Herein,a dimension-enhanced integral approach,by combining ultra-high performance liquid chromatography/ion mobility-quadrupole time-of-flight mass spectrometry(UHPLC/IMQTOF-MS)and intelligent peak annotation,was developed to rapidly characterize the multicomponents from SDS.Good chromatographic separation was achieved within 38 min on a UPLC CSH C18(2.1×100 mm,1.7μm)column which was eluted by 0.1%formic acid in water(water phase)and acetonitrile(organic phase).Collision-induced dissociation-MS^(2)data were acquired by the data-independent high-definition MS^(E)(HDMS^(E))in both the negative and positive electrospray ionization modes.A major components knockout strategy was applied to improve the characterization of those minor ingredients by enhancing the injection volume.Moreover,a self-built chemistry library was established,which could be matched by the UNIFI software enabling automatic peak annotation of the obtained HDMS^(E)data.As a result of applying the intelligent peak annotation workflows and further confirmation process,a total of 53 compounds were identified or tentatively characterized from the SDS,including 29 flavonoids,one uridine derivative,four glucosides,one lignin,one phenolic compound,and 17 others.Notably,four-dimensional information related to the structure(e.g.,retention time,collision cross section,MS^(1)and MS^(2)data)was obtained for each component by the developed integral approach,and the results would greatly benefit the quality control of SDS.展开更多
Quality control of ginseng currently is mainly based on ginsenoside analysis,but rarely focuses on the volatile organic components.In the current work,an untargeted metabolomics approach,by headspace solid-phase micro...Quality control of ginseng currently is mainly based on ginsenoside analysis,but rarely focuses on the volatile organic components.In the current work,an untargeted metabolomics approach,by headspace solid-phase micro-extraction gas chromatography/mass spectrometry(HS-SPME-GC/MS),was elaborated and further employed to holistically compare the compositional difference of the volatile components simultaneously from 12 Panax herbal medicines,which included P.ginseng(PG),P.quinquefolius(PQ),P.notoginseng(PN),red ginseng(PGR),P.ginseng leaf(PGL),P.quinquefolius leaf(PQL),P.notoginseng leaf(PNL),P.ginseng flower(PGF),P.quinquefolius flower(PQF),P.notoginseng flower(PNF),P.japonicus(PJ),and P.japonicus var.major(PJvm).Chromatographic separation was performed on an HP-5MS elastic quartz capillary column using helium as the carrier gas,enabling good resolution within 1 h.We were able to characterize totally 259 volatile compounds,including 82 terpenes(T),46 alcohols(Alc),29 ketones(K),25 aldehydes(Ald),21 esters(E),and the others.By analyzing 90 batches of ginseng samples based on the untargeted metabolomics workflows,236 differential ions were unveiled,and accordingly 36 differential volatile components were discovered.It is the first report that simultaneously compares the compositional difference of volatile components among 12 Panax herbal medicines,and useful information is provided for the quality control of ginseng aside from the well-known ginsenosides.展开更多
Garden soil test was used to study the effects of different cultivation time of garden plants on soil chemical properties and soil enzyme activities in the garden. The results showed that with the extension of cultiva...Garden soil test was used to study the effects of different cultivation time of garden plants on soil chemical properties and soil enzyme activities in the garden. The results showed that with the extension of cultivation time,the activity of protease,urease and catalase in Ginkgo biloba soil increased significantly,while the activity of protease in other garden plants showed a certain degree of decline,and the activity of urease increased significantly in the soil cultivated Lagerstroemia indica for over 3 years. However,in the soil cultivated the garden plants for less than 3 years,the difference in the activity of urease was relatively small,and the difference in the activity of catalase was relatively significant.展开更多
English writing, as a basic language skill for second language learners, is being paid close attention to. How to achieve better results in English teaching and how to develop students＇ writing competence remain an a...English writing, as a basic language skill for second language learners, is being paid close attention to. How to achieve better results in English teaching and how to develop students＇ writing competence remain an arduous task for English teachers. This paper introduces three writing approaches that are currently popular in English writing teaching field, i.e., the product approach, the process approach and the genre approach, and offers some discussion on the three approaches each approach shows its strengths and weaknesses, but meanwhile they are largely complementary. Then this paper attempts to propose an integrated approach which is not only a synthesis of the above three approaches, but also draws on some experiences of traditional Chinese language teaching methods.展开更多
The composition,provenance,and genetic mechanism of sediment on different sedimentary units of the East China Sea(ECS)shelf are essential for understanding the depositional dynamics environment in the ECS.The sediment...The composition,provenance,and genetic mechanism of sediment on different sedimentary units of the East China Sea(ECS)shelf are essential for understanding the depositional dynamics environment in the ECS.The sediments in the northern ECS shelf are distributed in a ring-shaped distribution centered on the southwestern Cheju Island Mud.From the inside to the outside,the grain size goes from fine to coarse.Aside from the“grain size effect”,hydrodynamic sorting and mineral composition are important restrictions on the content of rare earth elements(REEs).Based on the grain size,REEs,and clay mineral composition of 300 surface sediments,as well as the sedimentary genesis,the northern ECS shelf is divided into three geochemical zones:southwestern Cheju Island Mud Area(ZoneⅠ),Changjiang Shoal Sand Ridges(ZoneⅡ-1),Sand Ridges of the East China Sea shelf(ZoneⅡ-2).The northern ECS shelf is mostly impacted by Chinese mainland rivers(the Changjiang River and Huanghe River),and the provenance and transport mechanism of sediments of different grain sizes is diverse.The bulk sediments come primarily from the Changjiang River,with some material from the Huanghe River carried by the Yellow Sea Coastal Current and the North Jiangsu Coastal Current,and less from Korean rivers.Among them,surface sediments in the southwestern Cheju Island Mud Area(ZoneⅠ)come mostly from the Changjiang River and partly from the Huanghe River.It was formed by the counterclockwise rotating cold eddies in the northern ECS shelf,which caused the sedimentation and accumulation of the fine-grained sediments of the Changjiang River and the Huanghe River.The Changjiang Shoal Sand Ridges(ZoneⅡ-1)were developed during the early-middle Holocene sea-level highstand.It is the modern tidal sand ridge sediment formed by intense hydrodynamic action under the influence of the Yellow Sea Coastal Current,North Jiangsu Coastal Current,and Changjiang Diluted Water.The surface sediments mainly originate from the Changjiang River and Huanghe River,with the Changjiang River dominating,and the Korean River(Hanjiang River)influencing just a few stations.Sand Ridges of the East China Sea shelf(ZoneⅡ-2)are the relict sediments of the paleo-Changjiang River created by sea invasion at the end of the Last Deglaciation in the Epipleistocene.The clay mineral composition of the surface sediments in the study area is just dominated by the Changjiang River,with the North Jiangsu Coastal Current and the Changjiang Diluted Water as the main transporting currents.展开更多
This paper compares the effectiveness of one-semester-long instruction of teacher-student collaborative assessment(TSCA)and trained peer review assessment(TPRA).Dependent variables include occurrence of structural ele...This paper compares the effectiveness of one-semester-long instruction of teacher-student collaborative assessment(TSCA)and trained peer review assessment(TPRA).Dependent variables include occurrence of structural elements of the simplified Toulmin model,and improvement of argumentation substance which refers to the quality of reasoning reflected in Toulmin structural elements.Eighty-one sophomore English majors from TSCA group(n=41)and TPRA group(n=40)were asked to construct two argumentative essays at both the beginning and the end of the semester.The results reveal that the TSCA group produced significantly more counterargument claims and rebuttal data.Additionally,the TSCA group significantly outperformed TPRA group in constructing stronger counterargument claim,rebuttal claim and rebuttal data.展开更多
[ Objective] This study aimed to investigate the effects of Cu contamination in soils on GSH-Px （ glutathione peroxidase） activity of earthworms （ Eisenia fetida）. [ Method ] By artificial soil contamination metho...[ Objective] This study aimed to investigate the effects of Cu contamination in soils on GSH-Px （ glutathione peroxidase） activity of earthworms （ Eisenia fetida）. [ Method ] By artificial soil contamination method, changes in GSH-Px activity of earthworms under different Cu concentrations were investigated [ Result ] In the early exposure period, low-concentration Cu stress activated GSH-Px activity of earthworms to a certain extent; with the extension of extxqsure time and increase of Cu concentration, GSH-Px activity of earthworms showed a decreasing trend; however, under high-concentration Cu stress, there was no remarkable reg- ularity in the reduction of GSH-Px activity of earthworms. [ Conclusion] This study laid a solid foundation for further revealing the synergistic mechanism of antioxidant enzymes of earthworms.展开更多
Battery groups are widely used in production and life. Optimal charging can not only shorten the charge time, but also improve the performance and life of the battery pack. A constant current or constant voltage charg...Battery groups are widely used in production and life. Optimal charging can not only shorten the charge time, but also improve the performance and life of the battery pack. A constant current or constant voltage charging method is commonly used. This type of method cannot adjust the charge capacity in time according to the change of charging capacity of storage battery, and the charge performance is not high. This paper designs a fuzzy PID controller. In the case of variable load and interference, the battery group can still be charged by the optimal charging current. Through the simulation results, the fuzzy PID controller works well and verifies the feasibility of the charging controller.展开更多
The purpose of the present study was to investigate the effect of participation in a health motivation-based intervention program on college students’smoking behavior.One hundred and seventy smokers(mean age=19.0 yea...The purpose of the present study was to investigate the effect of participation in a health motivation-based intervention program on college students’smoking behavior.One hundred and seventy smokers(mean age=19.0 years,151 males)from nine colleges and universities in Chengdu,China were randomly assigned to one of 5 groups that received between one and four sessions of the intervention,or no intervention.The intervention sessions included sequential activities based on the stages of the process model of health motivation.Each group completed questionnaires assessing health motivation and smoking behaviors at pre-test,immediately post-intervention,and at one month follow-up.Analyses indicated that the intervention program did improve participants’health motivation,and that was associated with reduced levels of smoking relative to baseline.The greater the number of sessions,the greater the reduction in smoking.展开更多
In order to improve the dynamic performance and suppress current harmonic for seven-phase PMSM(permanent magnet synchronous motor),this paper proposed an MPCC(mode predict current control)scheme based on SVPWM(space v...In order to improve the dynamic performance and suppress current harmonic for seven-phase PMSM(permanent magnet synchronous motor),this paper proposed an MPCC(mode predict current control)scheme based on SVPWM(space vector pulse width modulation)technique.By this scheme,the 14 virtual voltage vectors are first calculated based on the principle:the voltage vector synthesized in the 3rd harmonic subspace and the 5th harmonic subspace should be zero,in each sampling period,the optimal voltage vector is directly selected from the 14 virtual voltage vectors to achieve the best output current performance of seven-phase PMSM.In addition,no cost function related calculations are required in the MPCC scheme,reducing the calculation time and improving the dynamic response of the system.The simulation model of the seven-phase PMSM vector control system is established by using the Simulink tool of MATLAB,and the effectiveness of the scheme will be presented.展开更多
文摘The significant impact of earthquakes on human lives and the built environment underscores the extensive human and economic losses caused by structural collapses. Over the years, researchers have focused on improving seismic design to mitigate earthquake-induced damages and enhance structural performance. In this study, a specific reinforced concrete (RC) frame structure at Kyungpook National University, designed for educational purposes, is analyzed as a representative case. Utilizing SAP 2000, the research conducts a nonlinear time history analysis to assess the structural performance under seismic conditions. The primary objective is to evaluate the influence of different column section designs, while maintaining identical column section areas, on structural behavior. The study employs two distinct seismic waves from Abeno (ABN) and Takatori (TKT) for the analysis, comparing the structural performance under varying seismic conditions. Key aspects examined include displacement, base shear force, base moment, joint radians, and layer displacement angle. This research is anticipated to serve as a valuable reference for seismic restraint reinforcement work on RC buildings, enriching the methods used for evaluating structures through nonlinear time history analysis based on the synthetic seismic wave approach.
文摘In contemporary society, reducing carbon dioxide emissions and achieving sustainable development are paramount goals. One effective approach is to preserve existing RC (Reinforced Concrete) buildings rather than demolishing them for new construction. However, a significant challenge arises from the lack of elevator designs in many of these existing RC buildings. Adding an external elevator becomes crucial to solving accessibility issues, enhancing property value, and satisfying modern residential buildings using convenient requirements. However, the structural performance of external elevator wells remains understudied. This research is designed by the actual external elevator project into existing RC buildings in Jinzhong Rd, Shanghai City. Specifically, this research examines five different external elevator wells under nonlinear pushover analysis, each varying in the height of the RC (Reinforced Concrete) footing. By analyzing plastic hinge states, performance points, capacity curves, spectrum curves, layer displacement, and drift ratio, this research aims to provide a comprehensive understanding of how these structures of the external elevator well respond to seismic events. The findings are expected to serve as a valuable reference for future external elevator projects, ensuring the external elevator designs meet the seismic requirements. By emphasizing seismic resistance in the design phase, the research aims to enhance the overall safety and longevity of external elevator systems integrated into existing RC buildings.
文摘Elevators are essential components of contemporary buildings, enabling efficient vertical mobility for occupants. However, the proliferation of tall buildings has exacerbated challenges such as traffic congestion within elevator systems. Many passengers experience dissatisfaction with prolonged wait times, leading to impatience and frustration among building occupants. The widespread adoption of neural networks and deep learning technologies across various fields and industries represents a significant paradigm shift, and unlocking new avenues for innovation and advancement. These cutting-edge technologies offer unprecedented opportunities to address complex challenges and optimize processes in diverse domains. In this study, LSTM (Long Short-Term Memory) network technology is leveraged to analyze elevator traffic flow within a typical office building. By harnessing the predictive capabilities of LSTM, the research aims to contribute to advancements in elevator group control design, ultimately enhancing the functionality and efficiency of vertical transportation systems in built environments. The findings of this research have the potential to reference the development of intelligent elevator management systems, capable of dynamically adapting to fluctuating passenger demand and optimizing elevator usage in real-time. By enhancing the efficiency and functionality of vertical transportation systems, the research contributes to creating more sustainable, accessible, and user-friendly living environments for individuals across diverse demographics.
文摘This paper studies the time-fractional Korteweg-de Vries (KdV) equations with Caputo-Fabrizio fractional derivatives. The scheme is presented by using a finite difference method in temporal variable and a local discontinuous Galerkin method (LDG) in space. Stability and convergence are demonstrated by a specific choice of numerical fluxes. Finally, the efficiency and accuracy of the scheme are verified by numerical experiments.
基金funding support from 1000 Talent Plan program(NO.31370086963030)research projects from Shandong Province(2018JMRH0211,2017CXGC1010 and 2016GGX104001)+2 种基金Taishan Scholar Program(11370085961006)the National Science Foundation of Shandong Province(ZR2017MEM002)the Fundamental Research Funds of Shandong University(201810422046,2017JC010,2017JC042,and 2016JC005)。
文摘High ionic conductivity and superior interfacial stability of solid electrolytes at the electrodes are crucial factors for high-performance all-solid-state sodium batteries. Herein, a composite solid electrolyte Na3PS4-polyethylene oxide is synthesized by the solution-phase reaction method with an improved ionic conductivity up to 9.4 × 10-5 S/cm at room temperature. Moreover, polyethylene oxide polymer layer is wrapped homogeneously on the surface of Na3PS4 particles, which could effectively avoid the direct contact between Na3PS4 electrolyte and sodium metal, thus alleviate their side reactions. We demonstrate that all-solid-state battery SnS2/Na with the composite solid electrolyte Na3PS4-polyethylene oxide delivers an enhanced electrochemical performance with 230 m Ah/g after 40 cycles.
基金This work was financially supported by the National Key Research and Development Program of China(Grant No.2018YFC1704500)Tianjin Committee of Science and Technology of China(Grant No.21ZYJDJC00080)National Natural Science Foundation of China(Grant No.81872996).
文摘The complex composition of herbal metabolites necessitates the development of powerful analytical techniques aimed to identify the bioactive components.The seeds of Descurainia sophia(SDS)are utilized in China as a cough and asthma relieving agent.Herein,a dimension-enhanced integral approach,by combining ultra-high performance liquid chromatography/ion mobility-quadrupole time-of-flight mass spectrometry(UHPLC/IMQTOF-MS)and intelligent peak annotation,was developed to rapidly characterize the multicomponents from SDS.Good chromatographic separation was achieved within 38 min on a UPLC CSH C18(2.1×100 mm,1.7μm)column which was eluted by 0.1%formic acid in water(water phase)and acetonitrile(organic phase).Collision-induced dissociation-MS^(2)data were acquired by the data-independent high-definition MS^(E)(HDMS^(E))in both the negative and positive electrospray ionization modes.A major components knockout strategy was applied to improve the characterization of those minor ingredients by enhancing the injection volume.Moreover,a self-built chemistry library was established,which could be matched by the UNIFI software enabling automatic peak annotation of the obtained HDMS^(E)data.As a result of applying the intelligent peak annotation workflows and further confirmation process,a total of 53 compounds were identified or tentatively characterized from the SDS,including 29 flavonoids,one uridine derivative,four glucosides,one lignin,one phenolic compound,and 17 others.Notably,four-dimensional information related to the structure(e.g.,retention time,collision cross section,MS^(1)and MS^(2)data)was obtained for each component by the developed integral approach,and the results would greatly benefit the quality control of SDS.
基金National Natural Science Foundation of China(Grant No.81872996)Natural Science Foundation of Tianjin of China(Grant No.20JCYBJC00060).
文摘Quality control of ginseng currently is mainly based on ginsenoside analysis,but rarely focuses on the volatile organic components.In the current work,an untargeted metabolomics approach,by headspace solid-phase micro-extraction gas chromatography/mass spectrometry(HS-SPME-GC/MS),was elaborated and further employed to holistically compare the compositional difference of the volatile components simultaneously from 12 Panax herbal medicines,which included P.ginseng(PG),P.quinquefolius(PQ),P.notoginseng(PN),red ginseng(PGR),P.ginseng leaf(PGL),P.quinquefolius leaf(PQL),P.notoginseng leaf(PNL),P.ginseng flower(PGF),P.quinquefolius flower(PQF),P.notoginseng flower(PNF),P.japonicus(PJ),and P.japonicus var.major(PJvm).Chromatographic separation was performed on an HP-5MS elastic quartz capillary column using helium as the carrier gas,enabling good resolution within 1 h.We were able to characterize totally 259 volatile compounds,including 82 terpenes(T),46 alcohols(Alc),29 ketones(K),25 aldehydes(Ald),21 esters(E),and the others.By analyzing 90 batches of ginseng samples based on the untargeted metabolomics workflows,236 differential ions were unveiled,and accordingly 36 differential volatile components were discovered.It is the first report that simultaneously compares the compositional difference of volatile components among 12 Panax herbal medicines,and useful information is provided for the quality control of ginseng aside from the well-known ginsenosides.
基金Supported by the Scientific Research Project of the Education Department of Sichuan(15ZA035)
文摘Garden soil test was used to study the effects of different cultivation time of garden plants on soil chemical properties and soil enzyme activities in the garden. The results showed that with the extension of cultivation time,the activity of protease,urease and catalase in Ginkgo biloba soil increased significantly,while the activity of protease in other garden plants showed a certain degree of decline,and the activity of urease increased significantly in the soil cultivated Lagerstroemia indica for over 3 years. However,in the soil cultivated the garden plants for less than 3 years,the difference in the activity of urease was relatively small,and the difference in the activity of catalase was relatively significant.
文摘English writing, as a basic language skill for second language learners, is being paid close attention to. How to achieve better results in English teaching and how to develop students＇ writing competence remain an arduous task for English teachers. This paper introduces three writing approaches that are currently popular in English writing teaching field, i.e., the product approach, the process approach and the genre approach, and offers some discussion on the three approaches each approach shows its strengths and weaknesses, but meanwhile they are largely complementary. Then this paper attempts to propose an integrated approach which is not only a synthesis of the above three approaches, but also draws on some experiences of traditional Chinese language teaching methods.
基金The National Natural Science Foundation of China under contract Nos 42276084 and 42176078the Special survey items of the China Geological Survey under contract Nos DD20190205 and DD20221710。
文摘The composition,provenance,and genetic mechanism of sediment on different sedimentary units of the East China Sea(ECS)shelf are essential for understanding the depositional dynamics environment in the ECS.The sediments in the northern ECS shelf are distributed in a ring-shaped distribution centered on the southwestern Cheju Island Mud.From the inside to the outside,the grain size goes from fine to coarse.Aside from the“grain size effect”,hydrodynamic sorting and mineral composition are important restrictions on the content of rare earth elements(REEs).Based on the grain size,REEs,and clay mineral composition of 300 surface sediments,as well as the sedimentary genesis,the northern ECS shelf is divided into three geochemical zones:southwestern Cheju Island Mud Area(ZoneⅠ),Changjiang Shoal Sand Ridges(ZoneⅡ-1),Sand Ridges of the East China Sea shelf(ZoneⅡ-2).The northern ECS shelf is mostly impacted by Chinese mainland rivers(the Changjiang River and Huanghe River),and the provenance and transport mechanism of sediments of different grain sizes is diverse.The bulk sediments come primarily from the Changjiang River,with some material from the Huanghe River carried by the Yellow Sea Coastal Current and the North Jiangsu Coastal Current,and less from Korean rivers.Among them,surface sediments in the southwestern Cheju Island Mud Area(ZoneⅠ)come mostly from the Changjiang River and partly from the Huanghe River.It was formed by the counterclockwise rotating cold eddies in the northern ECS shelf,which caused the sedimentation and accumulation of the fine-grained sediments of the Changjiang River and the Huanghe River.The Changjiang Shoal Sand Ridges(ZoneⅡ-1)were developed during the early-middle Holocene sea-level highstand.It is the modern tidal sand ridge sediment formed by intense hydrodynamic action under the influence of the Yellow Sea Coastal Current,North Jiangsu Coastal Current,and Changjiang Diluted Water.The surface sediments mainly originate from the Changjiang River and Huanghe River,with the Changjiang River dominating,and the Korean River(Hanjiang River)influencing just a few stations.Sand Ridges of the East China Sea shelf(ZoneⅡ-2)are the relict sediments of the paleo-Changjiang River created by sea invasion at the end of the Last Deglaciation in the Epipleistocene.The clay mineral composition of the surface sediments in the study area is just dominated by the Changjiang River,with the North Jiangsu Coastal Current and the Changjiang Diluted Water as the main transporting currents.
基金supported by China Foreign Language Education Fund(10th Batch)granted by Beijing Foreign Studies University,directed by Prof.Xiaoyan XU[Grant Number:ZGWYJYJJ10A130]Sichuan Research Center of Foreign Languages and LiteratureHigher Education Press,directed by Yuexin ZHONG[Grant Number:SCWYGJ21-10]。
文摘This paper compares the effectiveness of one-semester-long instruction of teacher-student collaborative assessment(TSCA)and trained peer review assessment(TPRA).Dependent variables include occurrence of structural elements of the simplified Toulmin model,and improvement of argumentation substance which refers to the quality of reasoning reflected in Toulmin structural elements.Eighty-one sophomore English majors from TSCA group(n=41)and TPRA group(n=40)were asked to construct two argumentative essays at both the beginning and the end of the semester.The results reveal that the TSCA group produced significantly more counterargument claims and rebuttal data.Additionally,the TSCA group significantly outperformed TPRA group in constructing stronger counterargument claim,rebuttal claim and rebuttal data.
基金Supported by Scientific Research Project of Sichuan Provincial Education De partment(15ZA0335)
文摘[ Objective] This study aimed to investigate the effects of Cu contamination in soils on GSH-Px （ glutathione peroxidase） activity of earthworms （ Eisenia fetida）. [ Method ] By artificial soil contamination method, changes in GSH-Px activity of earthworms under different Cu concentrations were investigated [ Result ] In the early exposure period, low-concentration Cu stress activated GSH-Px activity of earthworms to a certain extent; with the extension of extxqsure time and increase of Cu concentration, GSH-Px activity of earthworms showed a decreasing trend; however, under high-concentration Cu stress, there was no remarkable reg- ularity in the reduction of GSH-Px activity of earthworms. [ Conclusion] This study laid a solid foundation for further revealing the synergistic mechanism of antioxidant enzymes of earthworms.
文摘Battery groups are widely used in production and life. Optimal charging can not only shorten the charge time, but also improve the performance and life of the battery pack. A constant current or constant voltage charging method is commonly used. This type of method cannot adjust the charge capacity in time according to the change of charging capacity of storage battery, and the charge performance is not high. This paper designs a fuzzy PID controller. In the case of variable load and interference, the battery group can still be charged by the optimal charging current. Through the simulation results, the fuzzy PID controller works well and verifies the feasibility of the charging controller.
文摘The purpose of the present study was to investigate the effect of participation in a health motivation-based intervention program on college students’smoking behavior.One hundred and seventy smokers(mean age=19.0 years,151 males)from nine colleges and universities in Chengdu,China were randomly assigned to one of 5 groups that received between one and four sessions of the intervention,or no intervention.The intervention sessions included sequential activities based on the stages of the process model of health motivation.Each group completed questionnaires assessing health motivation and smoking behaviors at pre-test,immediately post-intervention,and at one month follow-up.Analyses indicated that the intervention program did improve participants’health motivation,and that was associated with reduced levels of smoking relative to baseline.The greater the number of sessions,the greater the reduction in smoking.
文摘In order to improve the dynamic performance and suppress current harmonic for seven-phase PMSM(permanent magnet synchronous motor),this paper proposed an MPCC(mode predict current control)scheme based on SVPWM(space vector pulse width modulation)technique.By this scheme,the 14 virtual voltage vectors are first calculated based on the principle:the voltage vector synthesized in the 3rd harmonic subspace and the 5th harmonic subspace should be zero,in each sampling period,the optimal voltage vector is directly selected from the 14 virtual voltage vectors to achieve the best output current performance of seven-phase PMSM.In addition,no cost function related calculations are required in the MPCC scheme,reducing the calculation time and improving the dynamic response of the system.The simulation model of the seven-phase PMSM vector control system is established by using the Simulink tool of MATLAB,and the effectiveness of the scheme will be presented.
