The increasing incidence of global warming and frequent heavy precipitation events presents a significant challenge for urban areas in managing extreme precipitation.Strengthening the resilience of communities to clim...The increasing incidence of global warming and frequent heavy precipitation events presents a significant challenge for urban areas in managing extreme precipitation.Strengthening the resilience of communities to climate change is a crucial strategy for fostering sustainable urban development.Green infrastructure offers an ecologically system for rainwater management and ecological restoration,and plays a significant role in adapting to climate risks.This study focuses on climate resilience by examining the implementation of green rainwater infrastructure within the context of climate-adapted green infrastructure in the High Point community of Seattle,USA,and proposes renewal planning strategies,methods,and implementation concepts at the community level.The research indicates that the High Point community has effectively mitigated the issue of waterlogging and enhanced the local microclimate through the implementation of green infrastructure systems,including permeable pavement,rain gardens,bioretention pools,and vegetative buffer zones.It is proposed that the collaborative design of green infrastructure should adhere to principles of systematization,alignment with natural processes,adaptation to the local environment,and engagement of multiple stakeholders,while considering various functions,diverse communities,and differing social contexts.Furthermore,it should be developed in consideration of the unique spatial characteristics,landscape structures,and social needs of each community.展开更多
The wheel-rail contact problems, such as the number, location and the track of contact patches, are very important for optimizing the spatial structure of the rails and lowering the vehicle-turnout system dynamics. Ho...The wheel-rail contact problems, such as the number, location and the track of contact patches, are very important for optimizing the spatial structure of the rails and lowering the vehicle-turnout system dynamics. However, the above problems are not well solved currently because of having the difficulties in how to determine the multi-contact, to preciously present the changeable profiles of the rails and to establish an accurate spatial turnout system dynamics model. Based on a high-speed vehicle-turnout coupled model in which the track is modeled as flexible with rails and sleepers represented by beams, the line tracing extreme point method is introduced to investigate the wheel-rail multiple contact conditions and the key sections of the blade rail, longer nose rail, shorter rail in the switch and nose rail area are discretized to represent the varying profiles of rails in the turnout. The dynamic interaction between the vehicle and turnout is simulated for cases of the vehicle divergently passing the turnout and the multi-point contact is obtained. The tracks of the contact patches on the top of the rails are presented and the wheel-rail impact forces are offered in comparison with the contact patches transference on the rails. The numerical simulation results indicate that the length of two-point contact occurrence of a worn wheel profile and rails is longer than that of the new wheel profile and rails; The two-point contact definitely occurs in the switch and crossing area. Generally, three-point contact doesn’t occur for the new rail profile, which is testified by the wheel-rails interpolation distance and the first order derivative function of the tracing line extreme points. The presented research is not only helpful to optimize the structure of the turnout, but also useful to lower the dynamics of the high speed vehicle-turnout system.展开更多
In thispaper,theexistence oftravelling frontsolution fora classofcom petition-diffu- sion system w ith high-order singular point w it = diw ixx - w αii fi(w ),x ∈R,t> 0,i= 1,2 (Ⅰ) is studied,w here di,αi>...In thispaper,theexistence oftravelling frontsolution fora classofcom petition-diffu- sion system w ith high-order singular point w it = diw ixx - w αii fi(w ),x ∈R,t> 0,i= 1,2 (Ⅰ) is studied,w here di,αi> 0 (i= 1,2) and w = (w 1(x,t),w 2(x,t)).Under the certain assum ptions on f,itis show ed thatifαi< 1 for som e i,then (Ⅰ) has no travelling frontsolution,ifαi≥1 for i= 1,2,then there isa c0,c:c0≥c> 0,w herecis called the m inim alwavespeed of(Ⅰ),such thatifc≥c0 orc= c,then (Ⅰ) has a travelling frontsolution,ifc< c,then (Ⅰ) hasno travel- ling frontsolution by using the shooting m ethod in com bination w ith a com pactness argum ent.展开更多
People living on the high plateaus of the world have long fascinated biological anthropologists and geneticists because they live in ＂thin air＂ and epitomize an extreme of human biological adaptation.
In the exploration of next-generation high-energy–density batteries,lithium metal is regarded as an ideal candidate for anode materials.However,lithium metal batteries (LMBs) face challenges in practical applications...In the exploration of next-generation high-energy–density batteries,lithium metal is regarded as an ideal candidate for anode materials.However,lithium metal batteries (LMBs) face challenges in practical applications due to the risks associated with organic liquid electrolytes,among which their low flash points are one of the major safety concerns.The adoption of high flash point quasi-solid polymer electrolytes(QSPE) that is compatible with the lithium metal anode and high-voltage cathode is therefore a promising strategy for exploring high-performance and high-safety LMBs.Herein,we employed the in-situ polymerization of poly (epoxidized soya fatty acid Bu esters-isooctyl acrylate-ditrimethylolpropane tetraacrylate)(PEID) to gel the liquid electrolyte that formed a PEID-based QSPE (PEID-QSPE).The flash point of PEID-QSPE rises from 25 to 82℃ after gelation,contributing to enhanced safety of the battery at elevated temperatures,whereas the electrochemical window increases to 4.9 V.Moreover,the three-dimensional polymer framework of PEID-QSPE is validated to facilitate the uniform growth of the solid electrolyte interphase on the anode,thereby improving the cycling stability of the battery.By employing PEID-QSPE,the Li|LiNi_(0.9)Co_(0.05)Mn_(0.05)O_(2) cell achieved long-term cycling stability (Coulombic efficiency,99.8%;>200 cycles at 0.1 C) even with a high cathode loading (~5 mg cm^(-2)) and an ultrathin Li(~50μm).This electrolyte is expected to afford inspiring insights for the development of safe and long-term cyclability LMBs.展开更多
In this paper, we consider two extended systems. When using them for the two parameter bifurcation problems, the simple bifurcation point with regard to lambda on turn into the simple turning point with. regard to mu....In this paper, we consider two extended systems. When using them for the two parameter bifurcation problems, the simple bifurcation point with regard to lambda on turn into the simple turning point with. regard to mu. Simple high orde bifurcation point is first studied without using the symmetry condition.展开更多
We consider double high order S-breaking bifurcation points of two-Parameter dependent nonlinear problems with Z_2×Z_2-symmetry. Because of the underlying symmetry we could propose some regular extended systems...We consider double high order S-breaking bifurcation points of two-Parameter dependent nonlinear problems with Z_2×Z_2-symmetry. Because of the underlying symmetry we could propose some regular extended systems to determine double high order S-breaking bifurcation points. and we could also show that there exist two quadratic pitchfork bifurcation point paths passing through the point being considered.展开更多
A single three point bend specimen compliance method for determining JIC of high strength high fracture toughness steels is presented and a formula for calculatinff J-integral is proposed as follows.It is simple and v...A single three point bend specimen compliance method for determining JIC of high strength high fracture toughness steels is presented and a formula for calculatinff J-integral is proposed as follows.It is simple and valid for high strength high fracture toughness steels. The values of JIC and KIC measured by this method are in good agreement with those measured by standard test method.展开更多
The appearance of 3D laser scanning technology is one of the most important technology revolutions in surveying and mapping field. It can be widely used in many interrelated fields, such as engineering constructions a...The appearance of 3D laser scanning technology is one of the most important technology revolutions in surveying and mapping field. It can be widely used in many interrelated fields, such as engineering constructions and 3D measurements, owing to its prominent characteristics of the high efficiency and high precision. At present its application is still in the initial state, and it is quite rarely used in China, especially in geotechnical engineering and geological engineering fields. Starting with a general introduction of 3D laser scanning technology, this article studies how to apply the technology to high rock slope investigations. By way of a case study, principles and methods of quick slope documentation and occurrence measurement of discontinuities are discussed and analyzed. Analysis results show that the application of 3D laser scanning technology to geotechnical and geological engineering has a great prospect and value.展开更多
Microstructural evolutions of the railway frog steel solidified under different pressure were studied using OM, FEGSEM, and TEM. The influences of pressure on the solidification, grain sizes, and morphology of carbide...Microstructural evolutions of the railway frog steel solidified under different pressure were studied using OM, FEGSEM, and TEM. The influences of pressure on the solidification, grain sizes, and morphology of carbides of the steel were analyzed. It is found that the melting point of the steel increases with the pressure and the solidified microstructure under high pressure does not vary significantly with the melting temperature. The experimental results show that the solidified microstructure consisting of complete equiaxed dendrites is remarkably refined through the increase of pressure, with the mean dendrite arm spacing of about 24, 18, and 8 μm under 3, 6, and 10 GPa, respectively. It is also revealed by TEM observation that the precipitates change from needle-like and rhombic carbide（M3C） forms during normal（atmospheric） pressure solidification into nodulized hexagonal precipitate M7C3 at 3 GPa, and M（23）C6 at 6 GPa and 10 GPa, which is associated with the undercooling and distribution of the trace elements. The diameter of the precipitates is between 80 nm and 200 nm.展开更多
文摘The increasing incidence of global warming and frequent heavy precipitation events presents a significant challenge for urban areas in managing extreme precipitation.Strengthening the resilience of communities to climate change is a crucial strategy for fostering sustainable urban development.Green infrastructure offers an ecologically system for rainwater management and ecological restoration,and plays a significant role in adapting to climate risks.This study focuses on climate resilience by examining the implementation of green rainwater infrastructure within the context of climate-adapted green infrastructure in the High Point community of Seattle,USA,and proposes renewal planning strategies,methods,and implementation concepts at the community level.The research indicates that the High Point community has effectively mitigated the issue of waterlogging and enhanced the local microclimate through the implementation of green infrastructure systems,including permeable pavement,rain gardens,bioretention pools,and vegetative buffer zones.It is proposed that the collaborative design of green infrastructure should adhere to principles of systematization,alignment with natural processes,adaptation to the local environment,and engagement of multiple stakeholders,while considering various functions,diverse communities,and differing social contexts.Furthermore,it should be developed in consideration of the unique spatial characteristics,landscape structures,and social needs of each community.
基金supported by National Natural Science Foundation of China (Grant Nos. 51175032, U1134201)National Basic Research Program of China (973 Program, Grant No. 2011CD711104)
文摘The wheel-rail contact problems, such as the number, location and the track of contact patches, are very important for optimizing the spatial structure of the rails and lowering the vehicle-turnout system dynamics. However, the above problems are not well solved currently because of having the difficulties in how to determine the multi-contact, to preciously present the changeable profiles of the rails and to establish an accurate spatial turnout system dynamics model. Based on a high-speed vehicle-turnout coupled model in which the track is modeled as flexible with rails and sleepers represented by beams, the line tracing extreme point method is introduced to investigate the wheel-rail multiple contact conditions and the key sections of the blade rail, longer nose rail, shorter rail in the switch and nose rail area are discretized to represent the varying profiles of rails in the turnout. The dynamic interaction between the vehicle and turnout is simulated for cases of the vehicle divergently passing the turnout and the multi-point contact is obtained. The tracks of the contact patches on the top of the rails are presented and the wheel-rail impact forces are offered in comparison with the contact patches transference on the rails. The numerical simulation results indicate that the length of two-point contact occurrence of a worn wheel profile and rails is longer than that of the new wheel profile and rails; The two-point contact definitely occurs in the switch and crossing area. Generally, three-point contact doesn’t occur for the new rail profile, which is testified by the wheel-rails interpolation distance and the first order derivative function of the tracing line extreme points. The presented research is not only helpful to optimize the structure of the turnout, but also useful to lower the dynamics of the high speed vehicle-turnout system.
文摘In thispaper,theexistence oftravelling frontsolution fora classofcom petition-diffu- sion system w ith high-order singular point w it = diw ixx - w αii fi(w ),x ∈R,t> 0,i= 1,2 (Ⅰ) is studied,w here di,αi> 0 (i= 1,2) and w = (w 1(x,t),w 2(x,t)).Under the certain assum ptions on f,itis show ed thatifαi< 1 for som e i,then (Ⅰ) has no travelling frontsolution,ifαi≥1 for i= 1,2,then there isa c0,c:c0≥c> 0,w herecis called the m inim alwavespeed of(Ⅰ),such thatifc≥c0 orc= c,then (Ⅰ) has a travelling frontsolution,ifc< c,then (Ⅰ) hasno travel- ling frontsolution by using the shooting m ethod in com bination w ith a com pactness argum ent.
文摘People living on the high plateaus of the world have long fascinated biological anthropologists and geneticists because they live in ＂thin air＂ and epitomize an extreme of human biological adaptation.
基金the S&T Program of Hebei (Grant Nos. 22344402D,22373709D)the National Natural Science Foundation of China(Grant Nos. 22108151, 22108202, 22109084, 22209010,22379014, and 22309101)+3 种基金the Beijing Natural Science Foundation(Grant Nos. Z200011, L233004)the Young Elite Scientists Sponsorship Program by CAST (Grant No. 2021QNRC001)the Seed Fund of Shanxi Research Institute for Clean Energythe support from the Department of Science and Technology of Jilin Province (Grant No. 20210301021GX)。
文摘In the exploration of next-generation high-energy–density batteries,lithium metal is regarded as an ideal candidate for anode materials.However,lithium metal batteries (LMBs) face challenges in practical applications due to the risks associated with organic liquid electrolytes,among which their low flash points are one of the major safety concerns.The adoption of high flash point quasi-solid polymer electrolytes(QSPE) that is compatible with the lithium metal anode and high-voltage cathode is therefore a promising strategy for exploring high-performance and high-safety LMBs.Herein,we employed the in-situ polymerization of poly (epoxidized soya fatty acid Bu esters-isooctyl acrylate-ditrimethylolpropane tetraacrylate)(PEID) to gel the liquid electrolyte that formed a PEID-based QSPE (PEID-QSPE).The flash point of PEID-QSPE rises from 25 to 82℃ after gelation,contributing to enhanced safety of the battery at elevated temperatures,whereas the electrochemical window increases to 4.9 V.Moreover,the three-dimensional polymer framework of PEID-QSPE is validated to facilitate the uniform growth of the solid electrolyte interphase on the anode,thereby improving the cycling stability of the battery.By employing PEID-QSPE,the Li|LiNi_(0.9)Co_(0.05)Mn_(0.05)O_(2) cell achieved long-term cycling stability (Coulombic efficiency,99.8%;>200 cycles at 0.1 C) even with a high cathode loading (~5 mg cm^(-2)) and an ultrathin Li(~50μm).This electrolyte is expected to afford inspiring insights for the development of safe and long-term cyclability LMBs.
文摘In this paper, we consider two extended systems. When using them for the two parameter bifurcation problems, the simple bifurcation point with regard to lambda on turn into the simple turning point with. regard to mu. Simple high orde bifurcation point is first studied without using the symmetry condition.
文摘We consider double high order S-breaking bifurcation points of two-Parameter dependent nonlinear problems with Z_2×Z_2-symmetry. Because of the underlying symmetry we could propose some regular extended systems to determine double high order S-breaking bifurcation points. and we could also show that there exist two quadratic pitchfork bifurcation point paths passing through the point being considered.
文摘A single three point bend specimen compliance method for determining JIC of high strength high fracture toughness steels is presented and a formula for calculatinff J-integral is proposed as follows.It is simple and valid for high strength high fracture toughness steels. The values of JIC and KIC measured by this method are in good agreement with those measured by standard test method.
基金the Key Project of Joint Funds of Yalongjiang River Development of the National Natural Science Foundation of China (No. 50539050)
文摘The appearance of 3D laser scanning technology is one of the most important technology revolutions in surveying and mapping field. It can be widely used in many interrelated fields, such as engineering constructions and 3D measurements, owing to its prominent characteristics of the high efficiency and high precision. At present its application is still in the initial state, and it is quite rarely used in China, especially in geotechnical engineering and geological engineering fields. Starting with a general introduction of 3D laser scanning technology, this article studies how to apply the technology to high rock slope investigations. By way of a case study, principles and methods of quick slope documentation and occurrence measurement of discontinuities are discussed and analyzed. Analysis results show that the application of 3D laser scanning technology to geotechnical and geological engineering has a great prospect and value.
基金Funded by the National Science and Technology Key Project(2011ZX06004-002)the Fundamental Research Funds for the Central Universities(No.YWF-10-01-B20)
文摘Microstructural evolutions of the railway frog steel solidified under different pressure were studied using OM, FEGSEM, and TEM. The influences of pressure on the solidification, grain sizes, and morphology of carbides of the steel were analyzed. It is found that the melting point of the steel increases with the pressure and the solidified microstructure under high pressure does not vary significantly with the melting temperature. The experimental results show that the solidified microstructure consisting of complete equiaxed dendrites is remarkably refined through the increase of pressure, with the mean dendrite arm spacing of about 24, 18, and 8 μm under 3, 6, and 10 GPa, respectively. It is also revealed by TEM observation that the precipitates change from needle-like and rhombic carbide（M3C） forms during normal（atmospheric） pressure solidification into nodulized hexagonal precipitate M7C3 at 3 GPa, and M（23）C6 at 6 GPa and 10 GPa, which is associated with the undercooling and distribution of the trace elements. The diameter of the precipitates is between 80 nm and 200 nm.
