This paper proposes a structure combined by baffle and submerged breakwater （abbreviated to SCBSB in the following texts）. Such a combined structure is conducive to the water exchange in the harbor, and has strong c...This paper proposes a structure combined by baffle and submerged breakwater （abbreviated to SCBSB in the following texts）. Such a combined structure is conducive to the water exchange in the harbor, and has strong capability on wave dissipation. Our paper focuses on the discussion of two typical structures, i.e., the submerged baffle and rectangular breakwater combined with the upper baffle respectively, which are named as SCBSB 1 and SCBSB2 for short. The eigenfunction method corrected by experimental results is used to investigate the wave dissipation characteristics. It shows that the calculated results agree well with the experimental data and the minimum value of the wave transmission coefficient can be obtained when the distance between the front and rear structures is from 1/4 to 1/2 of the incident wave length.展开更多
Starting from the variable separation solution obtained by using the extended homogenous balance method,a new class of combined structures, such as multi-peakon and multi-dromion solution, multi-compacton and multidro...Starting from the variable separation solution obtained by using the extended homogenous balance method,a new class of combined structures, such as multi-peakon and multi-dromion solution, multi-compacton and multidromion solution, multi-peakon and multi-compacton solution, for the (2+1)-dimensional Nizhnik-Novikov-Veselov equation are found by selecting appropriate functions. These new structures exhibit novel interaction features. Their interaction behavior is very similar to the completely nonelastic collisions between two classical particles.展开更多
For the requirement of safe and stable operation,the combined sealing structure was used for reciprocating motion in the deep sea high-pressure environment,and the effects of different seawater depths and shaft moveme...For the requirement of safe and stable operation,the combined sealing structure was used for reciprocating motion in the deep sea high-pressure environment,and the effects of different seawater depths and shaft movement speed on the sealing performance of the combined sealing structure were studied.The change rule of the sealing performance of the combined sealing structure of reciprocating motion under different working conditions is proved.The study shows that in the combined sealing structure of reciprocating movement,the Von Mises stress and the contact stress of the O-ring varies with the direction of the shaft movement.The Von Mises stress and contact stress of the O-ring,the Von Mises stress and the contact stress on each sealing lip of the slip ring gradually increase with the increasing of seawater depths.At the same time,the Von Mises stress of the O-ring which in the process of the shaft upward movement is greater than the shaft downward movement,making the shaft upward movement more likely to cause the O-ring relaxation and fatigue.The shaft movement speed has no significant influence on the Von Mises stress and contact stress of the O-ring.The research results provide theoretical guidance and technical support for the selection and optimization of the geometrical parameters of the combined sealing structure in the deep-sea high-pressure environment.展开更多
A combined dam structure using different concrete materials offers many practical benefits.There are several real-world cases where largevolume heterogeneous concrete materials have been used together.From the enginee...A combined dam structure using different concrete materials offers many practical benefits.There are several real-world cases where largevolume heterogeneous concrete materials have been used together.From the engineering design standpoint,it is crucial to understand the deformation coordination characteristics and mechanical properties of large-volume heterogeneous concrete,which affect dam safety and stability.In this study,a large dam facility was selected for a case study,and various design schemes of the combined dam structure were developed by changing the configurations of material zoning and material types for a given dam shape.Elastoplastic analysis of the damfoundation-reservoir system for six schemes was carried out under dynamic conditions,in which the concrete damaged plasticity(CDP)model,the Lagrangian finite element formulation,and a surface-to-surface contact model were utilized.To evaluate the mechanical properties of zoning interfaces and coordination characteristics,the vertical distribution of the first principal stress at the longitudinal joint was used as the critical index of deformation coordination control,and the overall deformation and damage characteristics of the dam were also investigated.Through a comparative study of the design schemes,an optimal scheme of the combined dam structure was identified:large-volume roller-compacted concrete(RCC)is recommended for the dam body upstream of the longitudinal joint,and high-volume fly ash conventional concrete(CC)for the dam body downstream of the longitudinal joint.This study provides engineers with a reference basis for combined dam structure design.展开更多
The finite element analysis was carried out for a composite vertical axis wind turbine with lift-drag combined starting structures to ensure the structure safety of a vertical axis wind turbine(VAWT).The static and mo...The finite element analysis was carried out for a composite vertical axis wind turbine with lift-drag combined starting structures to ensure the structure safety of a vertical axis wind turbine(VAWT).The static and modal analysis of rotor of a composite vertical axis wind turbine was conducted by using ANSYS software.The relevant contour sketch of stress and deformation was obtained.The analysis was made for static structural mechanics,modal analysis of rotor and the total deformation and vibration profile to evaluate the influence on the working capability of the rotor.The analysis results show that the various structure parameters lie in the safety range of structural mechanics in the relative standards.The analysis showing the design safe to operate the rotor of a vertical axis wind turbine.The methods used in this study can be used as a good reference for the structural mechanics′analysis of VAWTs.展开更多
Pile foundation bearing-retaining wall combination structure is a new type of support structure developed in recent years.This article focuses on the characteristics,advantages,and application scope of the support str...Pile foundation bearing-retaining wall combination structure is a new type of support structure developed in recent years.This article focuses on the characteristics,advantages,and application scope of the support structure,while combining a variety of algorithms,according to different geological conditions and slope stability,as well as summarizes the pile foundation bearing-retaining wall combination structure force analysis and design methods,taking a high-fill road project in Chongqing as an example.The application of this support structure under special conditions,such as thicker soil layer,steeper sliding surface,weak foundation,and limited slope release conditions,is presented,which illustrates the technical advantages of this support structure and proving that it has several other advantages,including clear force mechanism as well as economic and reasonable structure,thus providing reference for similar projects.展开更多
The mechanism of action of ecological factors affecting crop growth and development was complicated. In order to study the relationships between ecological factors and the indexes of yield property equation and determ...The mechanism of action of ecological factors affecting crop growth and development was complicated. In order to study the relationships between ecological factors and the indexes of yield property equation and determine the main ecological factors affecting yield, using 3-yr field experimental results for different yielding spring maize （Zea mays L.） populations and the relative meteorological observation data in Huadian of Jilin Province in China, and analyzing on the base of the yield property equation （MLAI × D × MNAR × HI = EN × GN × GW）, the main ecological factors were screened, and further mechanisms of action affecting yield were analyzed. Stepwise regression analysis showed that yield was affected mainly by effective accumulated temperature, daily mean minimum temperature, daily mean maximum temperature in July, the ratios of growth days, and the sunshine hour before and after silking. In yield property equation, four indexes of MLAI, growth days, ear number and grain number （total grain number） affected principally yield, the ecological factors affecting predominantly yield were effective accumulated temperature, daily mean temperature, daily mean minimum temperature, daily mean maximum temperature in July, the ratios of growth days, rainfall, accumulated temperature, and sunshine hours before and after silking. Combined with the two analytical methods, it could be deduced that the temperature and the allocated ratios before and after silking of ecological factors were the key factors to achieve high yield. Therefore, appropriate sowing data should be adjusted to achieve the suitable temperature indexes during the whole growth stage and the rational allocated ratios of ecological factors before and after silking.展开更多
The potential ecotoxicologial risks of methamidophos,copper,and their combinations on microbial community of black soil ecosystem in the Northeast China were assessed in species richness and structures by using 16S rD...The potential ecotoxicologial risks of methamidophos,copper,and their combinations on microbial community of black soil ecosystem in the Northeast China were assessed in species richness and structures by using 16S rDNA-PCR-DGGE analysis approach,and functional characteristics at community levels by using BIOLOG^(GN) system analysis method as well as two conventional methods(DHA and SIR).All results of DGGE banding fingerprint patterns(amplified by bacterial specific 16S rDNA V_(3) high variable region universal primer)indicated that the species richness of bacterial community in tested soil was significantly decreased to different extents by using different concentrations of single methamidophos,copper,especially some of their combinations had worse effects than their corresponding single factors.In addition,the structures of soil bacterial community had been disturbed under all stresses applied in this study because of the enrichment of some species and the disappearance of other species from the bacterial community.The effects of the single factors with lower concentrations on the communiy structure were weaker than those with higher concentrations.Moreover,the bacterial community structures under the combined stresses of methamidophos and copper were significantly different from those of control and their corresponding single factors.The change of DHA and carbon source substrate utilizing fingerprint patterns based on BIOLOG^(GN)system were two relatively sensitive directors corresponding to the stress presented in this study.Between methamodophos and copper,there happened the significant joint-toxic actions when they were used in combination on DHA and carbon source substrate utilizing fingerprint patterns of soil bacterial communities.The DHA of soil under the combined stresses was lower than that of the control and that under the single factors,and the BIOLOG^(GN) substrate utilizing patterns of soil treated by combinations were distinctively differentiated from the control and their corresponding single factors.From all of above,the methamidophos,copper,especially their combinations had the clearly potential ecotoxicological risks to influence the natural soil microbial ecological system by changing the structure,richness,and the functional characteristics of microbial community.展开更多
We propose a nonparallel double-grating structure in a spectral-beam combining technique, where two gratings are placed nonparallel satisfying the Littrow mount in the focal region of the convergent lens. The most att...We propose a nonparallel double-grating structure in a spectral-beam combining technique, where two gratings are placed nonparallel satisfying the Littrow mount in the focal region of the convergent lens. The most attractive advantage of this approach is that it will compress the spectral span into half of its original spectrum, which means the number of combined elements can be doubled in the gain range of diode lasers. Experimental results demonstrate that the CW output power of the combined beam is 30.9 W with a spectral span of 7.0 nm, compared with its original spectrum span of 13.6 nm, and the spectral beam combining efficiency is 70.5%. In consideration that a single grating could have a high efficiency of 〉97% in a bandwidth of over ten nanometers, the efficiency loss of the grating pair should be less than 6%, which is acceptable for most applications, so this method of using double gratings should be highly interesting for practical applications when a nearly doubled number of diode lasers could be combined into one single laser compared with the previous single-grating methods.展开更多
基金financially supported by the National Key R&D Program of China(Grant No.2017YFC0405402)
文摘This paper proposes a structure combined by baffle and submerged breakwater （abbreviated to SCBSB in the following texts）. Such a combined structure is conducive to the water exchange in the harbor, and has strong capability on wave dissipation. Our paper focuses on the discussion of two typical structures, i.e., the submerged baffle and rectangular breakwater combined with the upper baffle respectively, which are named as SCBSB 1 and SCBSB2 for short. The eigenfunction method corrected by experimental results is used to investigate the wave dissipation characteristics. It shows that the calculated results agree well with the experimental data and the minimum value of the wave transmission coefficient can be obtained when the distance between the front and rear structures is from 1/4 to 1/2 of the incident wave length.
文摘Starting from the variable separation solution obtained by using the extended homogenous balance method,a new class of combined structures, such as multi-peakon and multi-dromion solution, multi-compacton and multidromion solution, multi-peakon and multi-compacton solution, for the (2+1)-dimensional Nizhnik-Novikov-Veselov equation are found by selecting appropriate functions. These new structures exhibit novel interaction features. Their interaction behavior is very similar to the completely nonelastic collisions between two classical particles.
基金supported by the National Natural Science Foundation of China (Grant No.51705145, 51779092)the National Key Research and Development Program of China (Grant No.2016YFC0300502 and No.2017YFC0307501)+1 种基金Natural Science Foundation of Hunan Province of China (Grant No.2019JJ50182)Research Foundation of Education Bureau of Hunan Province (Grant No.18B205)
文摘For the requirement of safe and stable operation,the combined sealing structure was used for reciprocating motion in the deep sea high-pressure environment,and the effects of different seawater depths and shaft movement speed on the sealing performance of the combined sealing structure were studied.The change rule of the sealing performance of the combined sealing structure of reciprocating motion under different working conditions is proved.The study shows that in the combined sealing structure of reciprocating movement,the Von Mises stress and the contact stress of the O-ring varies with the direction of the shaft movement.The Von Mises stress and contact stress of the O-ring,the Von Mises stress and the contact stress on each sealing lip of the slip ring gradually increase with the increasing of seawater depths.At the same time,the Von Mises stress of the O-ring which in the process of the shaft upward movement is greater than the shaft downward movement,making the shaft upward movement more likely to cause the O-ring relaxation and fatigue.The shaft movement speed has no significant influence on the Von Mises stress and contact stress of the O-ring.The research results provide theoretical guidance and technical support for the selection and optimization of the geometrical parameters of the combined sealing structure in the deep-sea high-pressure environment.
基金supported by the National Natural Science Foundation of China(Grant No.51879185)the Fund of the National Dam Safety Research Center(Grant No.CX2019B02).
文摘A combined dam structure using different concrete materials offers many practical benefits.There are several real-world cases where largevolume heterogeneous concrete materials have been used together.From the engineering design standpoint,it is crucial to understand the deformation coordination characteristics and mechanical properties of large-volume heterogeneous concrete,which affect dam safety and stability.In this study,a large dam facility was selected for a case study,and various design schemes of the combined dam structure were developed by changing the configurations of material zoning and material types for a given dam shape.Elastoplastic analysis of the damfoundation-reservoir system for six schemes was carried out under dynamic conditions,in which the concrete damaged plasticity(CDP)model,the Lagrangian finite element formulation,and a surface-to-surface contact model were utilized.To evaluate the mechanical properties of zoning interfaces and coordination characteristics,the vertical distribution of the first principal stress at the longitudinal joint was used as the critical index of deformation coordination control,and the overall deformation and damage characteristics of the dam were also investigated.Through a comparative study of the design schemes,an optimal scheme of the combined dam structure was identified:large-volume roller-compacted concrete(RCC)is recommended for the dam body upstream of the longitudinal joint,and high-volume fly ash conventional concrete(CC)for the dam body downstream of the longitudinal joint.This study provides engineers with a reference basis for combined dam structure design.
文摘The finite element analysis was carried out for a composite vertical axis wind turbine with lift-drag combined starting structures to ensure the structure safety of a vertical axis wind turbine(VAWT).The static and modal analysis of rotor of a composite vertical axis wind turbine was conducted by using ANSYS software.The relevant contour sketch of stress and deformation was obtained.The analysis was made for static structural mechanics,modal analysis of rotor and the total deformation and vibration profile to evaluate the influence on the working capability of the rotor.The analysis results show that the various structure parameters lie in the safety range of structural mechanics in the relative standards.The analysis showing the design safe to operate the rotor of a vertical axis wind turbine.The methods used in this study can be used as a good reference for the structural mechanics′analysis of VAWTs.
基金Youth Project of Science and Technology Research of Chongqing Municipal Education Commission“Research on the Promotion of Pile Foundation Bearing-Retaining Wall Combined Structure Technology”(Project Number:KJQN201905601)Youth Project of Science and Technology Research of Chongqing Education Commission“Research on Construction Monitoring and Risk Warning of Deep Foundation Pit Project Based on BIM+Internet of Things”(Project Number:KJQN201904306)。
文摘Pile foundation bearing-retaining wall combination structure is a new type of support structure developed in recent years.This article focuses on the characteristics,advantages,and application scope of the support structure,while combining a variety of algorithms,according to different geological conditions and slope stability,as well as summarizes the pile foundation bearing-retaining wall combination structure force analysis and design methods,taking a high-fill road project in Chongqing as an example.The application of this support structure under special conditions,such as thicker soil layer,steeper sliding surface,weak foundation,and limited slope release conditions,is presented,which illustrates the technical advantages of this support structure and proving that it has several other advantages,including clear force mechanism as well as economic and reasonable structure,thus providing reference for similar projects.
基金supported by the National High-Tech Research and Development Program of China(2006AA10Z272)the National Basic Research Program of China (2006BAD02A13)
文摘The mechanism of action of ecological factors affecting crop growth and development was complicated. In order to study the relationships between ecological factors and the indexes of yield property equation and determine the main ecological factors affecting yield, using 3-yr field experimental results for different yielding spring maize （Zea mays L.） populations and the relative meteorological observation data in Huadian of Jilin Province in China, and analyzing on the base of the yield property equation （MLAI × D × MNAR × HI = EN × GN × GW）, the main ecological factors were screened, and further mechanisms of action affecting yield were analyzed. Stepwise regression analysis showed that yield was affected mainly by effective accumulated temperature, daily mean minimum temperature, daily mean maximum temperature in July, the ratios of growth days, and the sunshine hour before and after silking. In yield property equation, four indexes of MLAI, growth days, ear number and grain number （total grain number） affected principally yield, the ecological factors affecting predominantly yield were effective accumulated temperature, daily mean temperature, daily mean minimum temperature, daily mean maximum temperature in July, the ratios of growth days, rainfall, accumulated temperature, and sunshine hours before and after silking. Combined with the two analytical methods, it could be deduced that the temperature and the allocated ratios before and after silking of ecological factors were the key factors to achieve high yield. Therefore, appropriate sowing data should be adjusted to achieve the suitable temperature indexes during the whole growth stage and the rational allocated ratios of ecological factors before and after silking.
基金This work was supported in part by the Knowledge Innovation Engineering Action,the Chinese Academy of Sciences(KZCX2-SW-416)the National Natural Science Foundation of China(Grant No.20225722).
文摘The potential ecotoxicologial risks of methamidophos,copper,and their combinations on microbial community of black soil ecosystem in the Northeast China were assessed in species richness and structures by using 16S rDNA-PCR-DGGE analysis approach,and functional characteristics at community levels by using BIOLOG^(GN) system analysis method as well as two conventional methods(DHA and SIR).All results of DGGE banding fingerprint patterns(amplified by bacterial specific 16S rDNA V_(3) high variable region universal primer)indicated that the species richness of bacterial community in tested soil was significantly decreased to different extents by using different concentrations of single methamidophos,copper,especially some of their combinations had worse effects than their corresponding single factors.In addition,the structures of soil bacterial community had been disturbed under all stresses applied in this study because of the enrichment of some species and the disappearance of other species from the bacterial community.The effects of the single factors with lower concentrations on the communiy structure were weaker than those with higher concentrations.Moreover,the bacterial community structures under the combined stresses of methamidophos and copper were significantly different from those of control and their corresponding single factors.The change of DHA and carbon source substrate utilizing fingerprint patterns based on BIOLOG^(GN)system were two relatively sensitive directors corresponding to the stress presented in this study.Between methamodophos and copper,there happened the significant joint-toxic actions when they were used in combination on DHA and carbon source substrate utilizing fingerprint patterns of soil bacterial communities.The DHA of soil under the combined stresses was lower than that of the control and that under the single factors,and the BIOLOG^(GN) substrate utilizing patterns of soil treated by combinations were distinctively differentiated from the control and their corresponding single factors.From all of above,the methamidophos,copper,especially their combinations had the clearly potential ecotoxicological risks to influence the natural soil microbial ecological system by changing the structure,richness,and the functional characteristics of microbial community.
基金supported by the Shanghai Science and Technology Committee(Nos.16DZ2290102 and15JC1403500)the Chinese Academy of Sciences(No.QYZDJ-SSW-JSC014)the National Natural Science Foundation of China(No.61405216)
文摘We propose a nonparallel double-grating structure in a spectral-beam combining technique, where two gratings are placed nonparallel satisfying the Littrow mount in the focal region of the convergent lens. The most attractive advantage of this approach is that it will compress the spectral span into half of its original spectrum, which means the number of combined elements can be doubled in the gain range of diode lasers. Experimental results demonstrate that the CW output power of the combined beam is 30.9 W with a spectral span of 7.0 nm, compared with its original spectrum span of 13.6 nm, and the spectral beam combining efficiency is 70.5%. In consideration that a single grating could have a high efficiency of 〉97% in a bandwidth of over ten nanometers, the efficiency loss of the grating pair should be less than 6%, which is acceptable for most applications, so this method of using double gratings should be highly interesting for practical applications when a nearly doubled number of diode lasers could be combined into one single laser compared with the previous single-grating methods.
