Cassirer argues that humans are animals of symbols,and these symbolic forms encompass not only the science of rational logic but also non-logical elements such as mythology and primitive religions.Previous research on...Cassirer argues that humans are animals of symbols,and these symbolic forms encompass not only the science of rational logic but also non-logical elements such as mythology and primitive religions.Previous research on Cassirer’s philosophy of symbolic forms has primarily focused on philosophical connotations,philosophical thoughts,cultural philosophy,and other aspects,yielding abundant results.By examining mythology within the context of symbolic forms,we discover a force within it,namely,the solidifying power.This solidifying power demands that mythology maintain fixed and established forms during its emergence and development,thereby distinguishing it from other symbolic forms.By exploring the development trends and manifestations of the solidifying power in mythology,we can gain a clearer understanding of the path of human intellectual development from childhood to maturity,thus answering the historical question of human essence.展开更多
On the basis of the creep test of bigh-water materisl solidifying backfill body(abb. HW body), This paper discusses its creep properties- The visco-elasto-plastic model, which shows the creep properties of HW body, is...On the basis of the creep test of bigh-water materisl solidifying backfill body(abb. HW body), This paper discusses its creep properties- The visco-elasto-plastic model, which shows the creep properties of HW body, is developed, and the creep contitutive equations are deduced. The visco-elastoplastic model is proved by the experiments and practice.展开更多
On the basis of analysis of the structure aud loading characteristic of downward drift with high-water solidifying backfill, the fracture characteristics of the artiricial roof of "hard-support weak-plate" d...On the basis of analysis of the structure aud loading characteristic of downward drift with high-water solidifying backfill, the fracture characteristics of the artiricial roof of "hard-support weak-plate" drift and "soft-support weak-plate" drift are demonstrated rrom theory. The location and the maximum tensile stress of destruction point are given.This paper aims at providing some theoretical basis and practical reference for designing the artificlal roof structure parameter in downward drirt backfill mining.展开更多
The feasibility of producing graphite gangue wall body materials was discussed by the experiments of four kinds of hardeners solidifying graphite gangue.The result demonstrates that the physical performances of graphi...The feasibility of producing graphite gangue wall body materials was discussed by the experiments of four kinds of hardeners solidifying graphite gangue.The result demonstrates that the physical performances of graphite gangue solidified brick samples with 8% hardener D reach the senior grade or the special grade in JC422-91.The study of solidification mechanism indicates that the hardeners produced pastes while being hydrated.In addition,they can activate the mineral compositions in clay to join in the reaction to produce pastes and intensive framework.展开更多
Recycled powder(RP)is produced as a by-product during the process of recycling construction and demolition(C&D)wastes,presenting a low additional value.Using RP-based solidifying material can not only improve its ...Recycled powder(RP)is produced as a by-product during the process of recycling construction and demolition(C&D)wastes,presenting a low additional value.Using RP-based solidifying material can not only improve its utilization efficiency,but also reduce the cost of commercial solidifying materials.To date,this is the best solidifying material utilized to dispose the original waterworks sludge(OWS)with high moisture contents(60%),and the product could be used to fabricate non-fired bricks.This has become a new environment-friendly technology of“using waste to treat waste”.In this paper,the influence of different particle sizes and dosages of RP on the prepared solidifying material was studied.Besides,unconfined compression strength(UCS),volume stability,chemical composition,and heat of hydration,pore structure of the solidifying material were characterized.Then,non-fired bricks were prepared by using the solidifying material,recycled aggregate,and original waterworks sludge.The UCS and softing coefficient(SC)of the non-fired bricks were evaluated.As a result,the 28-day UCS of the solidifying material with optimal(M30)was 35.40 MPa,which could reach 84.37%of Portland cement(PC).The addition of RP increased the volume stability of the solidifying material.The addition of a large amount of RP reduced the heat flux and cumulative heat release of the solidifying material,while its porosity increased.The UCS of non-fired brick(NF20)in 28 days was 15.19 MPa and the SC after 28 days was 78.35%.In conclusion,the preparation of solidifying material using RP could be a promising approach and has a great potential in disposal of original waterworks sludge.展开更多
Transport structures built throughout the period from 1960 to 1980 in permafrost regions based on the principle of permafrost preservation are subject to deformations.In many cases,the reason is a gradual change in te...Transport structures built throughout the period from 1960 to 1980 in permafrost regions based on the principle of permafrost preservation are subject to deformations.In many cases,the reason is a gradual change in temperature and their subgrade condition within the active zone due to the structures'technogenic impact.Design solutions for the fifty-year-old structures fail to ensure in all cases their reliable operation at the present time.The greatest danger to the reliable operation of railway lines in cold regions is uneven deformations of bridges,which are barrier places.Therefore,the solution to this problem is urgent especially due to the necessity of increase carrying capacity.The purpose of this study is to increase reliability of bridge operation in cold regions through strengthening the subgrade by reinforcement with injection of solidifying solutions.The problem of uneven deformations due to permafrost degradation is considered using the example of a railway bridge located in the northern line of the Krasnoyarsk railway.Deformations of the bridge abutments began immediately after the construction was completed and the bridge was open for traffic-since 1977.Permafrost degradation was developing more actively straight under the abutments due to higher thermal conductivity of the piles concrete.Notably,thawing intensity of frozen soils under the bridge abutments is uneven due to its orientation to the cardinal points.The analysis of archive materials and results of the geodetic survey made it possible to systematize the features of augmenting deformations of each abutment over time.The engineering-geological survey with drilling wells near the abutments ensured determination of soil characteristics,both in the frozen and thawed states.Thermometric wells were arranged to measure temperatures.The analysis and systematization of the data obtained allowed us to develop geotechnical models for each abutment of the bridge.The peculiarity of these models is allowance for changes in the strength and deformation characteristics of the soil calculated layers depending on changes in temperature and the soil condition.Thus,different calculated geological elements with the corresponding strength and deformation characteristics were identified in the soil layers of the same origin.The analysis of the systematized geodetic data allowed us to confirm adequacy of the developed geotechnical models.Studies carried out using geotechnical models made it possible to predict improvement of physical and mechanical characteristics of the subgrade to prevent further growth deformations of the bridge abutments.The method of reinforcement by injection is proposed.Injecting a solution under pressure leads to strengthening of weakened thawed soils and improving their physical and mechanical properties.This research theoretically substantiates and develops the geotechnical models of the reinforced pier footing of bridge abutments by injection of solidifying solutions.The models take into account the reinforcement parameters and elements for the case in question.The influence of reinforcement on the change in physical and mechanical properties of the soil mass is determined.展开更多
High-water material, tailings from goldmine and water are mixed into a new slurry.Testing of rheological properties of stowing slurries A and B is made to determine type and rheological parameters of the slurry. The m...High-water material, tailings from goldmine and water are mixed into a new slurry.Testing of rheological properties of stowing slurries A and B is made to determine type and rheological parameters of the slurry. The main factors influencing rheological properties of the slurry are analyzed and the rational concentration and empirical resistance calculating formula of pipe line transportation are presented.展开更多
Children recurrent respiratory infection （CRRI） indicates that children suffer from frequent infections along the upper or lower respiratory tract for a certain number of times. It is not an independent disease but ...Children recurrent respiratory infection （CRRI） indicates that children suffer from frequent infections along the upper or lower respiratory tract for a certain number of times. It is not an independent disease but a clinical syndrome mostly brought about by some basic diseases such as nonspecific immunity, specific immune suppression or deficiency disease, congenital bronchopulmonary dysplasia, vitamin or microelement deficiency, or is induced by some factors such as smoking, cross infection, and nursing errors.（2） Clinically, CRRI is commonly treated by anti-infective agents, symptomatic and supportive treatment, and immune-regulatory therapy. However, the therapeutic effectiveness is always imperfect, which could even lead to a premium on asthma, or nephritis, etc.展开更多
We examined the enhancing effects of different dosages of product of Centrifugation of Bacterial Liquid(product of CBL)on the performance of slag-fGD gypsum-cement-bentonite-sludge system using MICP technology.We anal...We examined the enhancing effects of different dosages of product of Centrifugation of Bacterial Liquid(product of CBL)on the performance of slag-fGD gypsum-cement-bentonite-sludge system using MICP technology.We analyzed the multifaceted performance of the solidified sludge from macroscopic and microscopic perspectives.The experimental results reveal that the increase in product of CBL dosage results in positive impacts on the solidified sludge,including higher side compressive strength,lower leachate heavy metal concentration,and improved crack repair rates.At a 0.4%product of CBL doping concentration,the strength of the solidified sludge is enhanced by 26.6%at 3 d,61.2%at 7 d,and 13.9%at 28 d when compared to the unmodified solidified sludge.After 28 days,the concentrations of Zn and Cu ions reduce by 58%and 18%,respectively,and the crack repair rate is 58.4%.These results demonstrate that the increase in heavy metal concentration in the leachate leads to an increase in the strength of the solidified sludge.The strengthening procedure heavily relies on the mineralisation reaction of Bacillus pasteurii,which produces a substantial amount of CaCO_(3)to cement the particles and fill the pores initially.The modified solidifying sludge exhibits a self-repairing effect and an enhanced multifaceted performance as a result of oxygen being restored after crack formation and reactivation of Bacillus pasteurii.Such conditions facilitate the body's recovery.展开更多
High pressure die casting(HPDC)AlSi10Mn Mg alloy castings are widely used in the automobile industry.Mg can optimize the mechanical properties of castings through heat treatment,while the release of thermal stress aro...High pressure die casting(HPDC)AlSi10Mn Mg alloy castings are widely used in the automobile industry.Mg can optimize the mechanical properties of castings through heat treatment,while the release of thermal stress arouses the deformation of large integrated die-castings.Herein,the development of non-heat treatment Al alloys is becoming the hot topic.In addition,HPDC contains externally solidified crystals(ESCs),which are detrimental to the mechanical properties of castings.To achieve high strength and toughness of non-heat treatment die-casting Al-Si alloy,we used AlSi9Mn alloy as matrix with the introduction of Zr,Ti,Nb,and Ce.Their influences on ESCs and mechanical properties were systematically investigated through three-dimensional reconstruction and thermodynamic simulation.Our results reveal that the addition of Ti increased ESCs'size and porosity,while the introduction of Nb refined ESCs and decreased porosity.Meanwhile,large-sized Al_3(Zr,Ti)phases formed and degraded the mechanical properties.Subsequent introduction of Ce resulted in the poisoning effect and reduced mechanical properties.展开更多
Living organisms have developed their unique strategies during the natural evolution for building hard tissues with minerals,including silica,calcium carbonate,calcium phosphate,and ferric oxide [1].Such biomineralize...Living organisms have developed their unique strategies during the natural evolution for building hard tissues with minerals,including silica,calcium carbonate,calcium phosphate,and ferric oxide [1].Such biomineralized materials generally have complex hierarchical structures with excellent mechanical properties.Although bioinspired approaches have led to the creation of well-defined synthetic structural materials ranging from micro to macro scales,the rational design of discrete biomimetic structures at the nanoscale remains a grand challenge.展开更多
Loess slopes in cold and arid regions are susceptible to shallow soil degradation,which may trigger severe environmental problems related to soil erosion.To address this environmental challenge,this study selected a c...Loess slopes in cold and arid regions are susceptible to shallow soil degradation,which may trigger severe environmental problems related to soil erosion.To address this environmental challenge,this study selected a compound ecological curing agent composed of gellan gum and guar gum for stabilizing shallow loess slopes.Triaxial compression and disintegration tests were employed to comparatively analyze the effects of compound gum content,mass mix ratio,and curing age on the mechanical and disintegration properties of solidified loess.The curing mechanism was analyzed using scanning electron microscopy(SEM),and the ecological protection effect was monitored for a 60-day period.The results indicate that gellan gum,guar gum,and the compound gum can enhance the mechanical and disintegration properties of loess,promote plant growth,and optimize the ecological environment.However,the combination of gellan gum and guar gum proves more effective than using either gellan gum or guar gum alone.Considering the effects on mechanical properties,disintegration performance,and material economy,the disintegration rate of loess decreases by 75.72%compared to plain loess when the compound glue content is 0.5%,the mixing ratio of gellan gum to guar gum is 3:7 and the curing age is 7 days.Meanwhile,the cohesion and internal friction angle increase by 118.06%and 10.97%,respectively.Moreover,the disintegration performance and mechanical properties of the samples first increase and then decrease with the increase in compound glue and the mix ratio and are basically stabilized after the curing age reaches 7d.展开更多
During the continuous casting process of low carbon steel,the solidified hook formed in the mold has great effects on the surface quality of the cast slab.Some factory experiments have been conducted to investigate th...During the continuous casting process of low carbon steel,the solidified hook formed in the mold has great effects on the surface quality of the cast slab.Some factory experiments have been conducted to investigate the microscopic characteristics and reveal the influence of process parameters on solidified hooks.The depth of the hooks showed a positive correlation with the deflection angle,length,and oscillation mark(OM)depth,which indicates that the OM depth can serve as an approximate indicator for evaluating the depth of the solidified hooks.On the wide and narrow faces of the cast slab,the depth of the solidified hooks and the temperature distribution in the mold show opposite trends,with lower depths of solidified hooks at positions with higher temperatures.In addition,the influence of process parameters on solidified hooks was analyzed.With the increase in superheat,not only the depth of solidified hooks gradually decreases,but also the ratio of depression-typed marks increases.Increasing casting speed and decreasing immersion depth of the submerged entry nozzle will both lead to a decrease in the depth of the solidified hook.展开更多
Fluidized solidified soil(FSS)is an innovative backfill material that offers benefits such as easy pumping and straightforward construction.This study examined how varying the water-soil ratio and the curing agent dos...Fluidized solidified soil(FSS)is an innovative backfill material that offers benefits such as easy pumping and straightforward construction.This study examined how varying the water-soil ratio and the curing agent dosage affect the properties and microstructure of FSS.The strength development mechanism was investigated when composite solidification agents were used.The findings show that both the water-solid ratio and the curing agent dosage can affect the microstructure of FSS,thereby affecting its performance.When the water-solid ratio increases from 0.52 to 0.56,the unconfined compressive strength(UCS)and flexural strength of the FSS decrease by 34.1% and 39.3% after 28 d.Conversely,the curing agent dosage increasing from 10% to 30% will increase both UCS and flexural strength by 11.2 times and 11.1 times.As the curing age increases,the number of cracks at failure point in the FSS will increase and lead to a more complete failure.Numerous needle-like AFt,C-S-H gel,and C-(A)-S-H gel create a three-dimensional network by adhering to soil particles.展开更多
The effect of slow shot speed on externally solidified crystal(ESC),porosity and tensile property in a newly developed high-pressure die-cast Al-Si alloy was investigated by optical microscopy(OM),scanning electron mi...The effect of slow shot speed on externally solidified crystal(ESC),porosity and tensile property in a newly developed high-pressure die-cast Al-Si alloy was investigated by optical microscopy(OM),scanning electron microscopy(SEM)and laboratory computed tomography(CT).Results showed that the newly developed AlSi9MnMoV alloy exhibited improved mechanical properties when compared to the AlSi10MnMg alloy.The AlSi9MnMoV alloy,which was designed with trace multicomponent additions,displays a notable grain refining effect in comparison to the AlSi10MnMg alloy.Refining elements Ti,Zr,V,Nb,B promote heterogeneous nucleation and reduce the grain size of primaryα-Al.At a lower slow shot speed,the large ESCs are easier to form and gather,developing into the dendrite net and net-shrinkage.With an increase in slow shot speed,the size and number of ESCs and porosities significantly reduce.In addition,the distribution of ESCs is more dispersed and the net-shrinkage disappears.The tensile property is greatly improved by adopting a higher slow shot speed.The ultimate tensile strength is enhanced from 260.31 MPa to 290.31 MPa(increased by 11.52%),and the elongation is enhanced from 3.72%to 6.34%(increased by 70.52%).展开更多
Unique rapid solidified structure and nanocrystallization mechanism enable the Fe-based nanocrystalline alloys with high Cu content excellent soft magnetic properties and good manufacturability,and also results in unu...Unique rapid solidified structure and nanocrystallization mechanism enable the Fe-based nanocrystalline alloys with high Cu content excellent soft magnetic properties and good manufacturability,and also results in unusual phenomena in terms of alloying effects.In the present work,we systematically studied the influence rules of early transition elements on the rapid solidified structure and nanocrystallization behaviors of Fe-Si-B-Cu soft magnetic alloys with high Cu content and explored the related mechanisms.In terms of rapid solidified structure,the additions of early transition elements always inhibit the for-mation of pre-existingα-Fe crystals even eliminate them,and the additions that could produce larger atomic mismatch parameter(δ)and negative mixing enthalpy(△H_(mix))show stronger effects.In terms of nanocrystallization behaviors,the increases inδand negative△H_(mix) weaken the competitive growth between the pre-existing nanocrystals during annealing and then coarsen the nanostructure of the an-nealed alloys and deteriorate their magnetic softness,while the excessive increases inδand negativeHmix could significantly suppress the growth ofα-Fe crystals by diffusion inhibition during annealing and thus remarkable refine the nanostructure of the annealed alloys and improve their magnetic softness.展开更多
A new scour countermeasure using solidified slurry for offshore foundation has been proposed recently.Fluidized solidified slurry is pumped to seabed area around foundation for scour protection or pumped into the deve...A new scour countermeasure using solidified slurry for offshore foundation has been proposed recently.Fluidized solidified slurry is pumped to seabed area around foundation for scour protection or pumped into the developed scour holes for scour repair as the fluidized material solidifies gradually.In the pumping operation and solidification,the engineering behaviors of solidified slurry require to be considered synthetically for the reliable application in scour repair and protection of ocean engineering such as the pumpability related flow value,flow diffusion behavior related rheological property,anti-scour performance related retention rate in solidification and bearing capacity related strength property after solidification.In this study,a series of laboratory tests are conducted to investigate the effects of mix proportion(initial water content and binder content)on the flow value,rheological properties,density,retention rate of solidified slurry and unconfined compressive strength(UCS).The results reveal that the flow value increases with the water content and decreases with the binder amount.All the solidified slurry exhibits Bingham plastic behavior when the shear rate is larger than 5 s^(-1).The Bingham model has been employed to fit the rheology test results,and empirical formulas for obtaining the density,yield stress and viscosity are established,providing scientific support for the numerical assessment of flow and diffusion of solidified slurry.Retention rate of solidified slurry decreases with the water flow velocity and flow value,which means the pumpability of solidified slurry is contrary to anti-scour performance.The unconfined compressive strength after solidification reduces as the water content increases and binder content decreases.A design and application procedure of solidified soil for scour repair and protection is also proposed for engineering reference.展开更多
The oxidation and interdiffusion behavior of a novel AlCoCrFeNiY bond coat deposited on a directionally solidified Ni-based superalloy were systematically studied at 1050,1100 and 1150°C,and compared with a conve...The oxidation and interdiffusion behavior of a novel AlCoCrFeNiY bond coat deposited on a directionally solidified Ni-based superalloy were systematically studied at 1050,1100 and 1150°C,and compared with a conventional NiCoCrAlY coating deposited on the same substrate.The AlCoCrFeNiY bond coat exhibits lower oxide growth rates due to its large columnar grains and low Al activity at the oxide scale/bond coat interface.Meanwhile,AlCoCrFeNiY has higher resistance to oxide spallation than NiCoCrAlY,which is attributed to the formation of a clean and defect-free metal/oxide interface.Significant interdiffusion occurs across the AlCoCrFeNiY/superalloy substrate interface.Our experimental evidence and thermody-namic modelling suggest that Fe accelerates interdiffusion and destabilizes theγ’phase,thereby causing the formation of a thick andγ’-depleted interdiffusion zone.In addition,the AlCoCrFeNiY bond coat un-dergoes more Al depletion and subsequentβtoγtransformation compared with NiCoCrAlY.Based on the findings in this work,a novel AlCoCrFeNiY/NiCoCrAlY double-layer bond coat was designed,tested and validated to achieve optimal balance between oxidation and interdiffusion.展开更多
文摘Cassirer argues that humans are animals of symbols,and these symbolic forms encompass not only the science of rational logic but also non-logical elements such as mythology and primitive religions.Previous research on Cassirer’s philosophy of symbolic forms has primarily focused on philosophical connotations,philosophical thoughts,cultural philosophy,and other aspects,yielding abundant results.By examining mythology within the context of symbolic forms,we discover a force within it,namely,the solidifying power.This solidifying power demands that mythology maintain fixed and established forms during its emergence and development,thereby distinguishing it from other symbolic forms.By exploring the development trends and manifestations of the solidifying power in mythology,we can gain a clearer understanding of the path of human intellectual development from childhood to maturity,thus answering the historical question of human essence.
文摘On the basis of the creep test of bigh-water materisl solidifying backfill body(abb. HW body), This paper discusses its creep properties- The visco-elasto-plastic model, which shows the creep properties of HW body, is developed, and the creep contitutive equations are deduced. The visco-elastoplastic model is proved by the experiments and practice.
文摘On the basis of analysis of the structure aud loading characteristic of downward drift with high-water solidifying backfill, the fracture characteristics of the artiricial roof of "hard-support weak-plate" drift and "soft-support weak-plate" drift are demonstrated rrom theory. The location and the maximum tensile stress of destruction point are given.This paper aims at providing some theoretical basis and practical reference for designing the artificlal roof structure parameter in downward drirt backfill mining.
基金FundedbyNaturalScienceYouthFoundationofShandongProvince (No .Q2 0 0 1F0 1)
文摘The feasibility of producing graphite gangue wall body materials was discussed by the experiments of four kinds of hardeners solidifying graphite gangue.The result demonstrates that the physical performances of graphite gangue solidified brick samples with 8% hardener D reach the senior grade or the special grade in JC422-91.The study of solidification mechanism indicates that the hardeners produced pastes while being hydrated.In addition,they can activate the mineral compositions in clay to join in the reaction to produce pastes and intensive framework.
基金This work was supported by the Jiangsu Provincial Science and Technology Department’s Social Development-Major Science and Technology Demonstration Project(Grant No.BE2018697)the Demonstration Engineering Technology Research Center of Suqian Science and Technology Bureau(Grant No.M201912)a Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions.
文摘Recycled powder(RP)is produced as a by-product during the process of recycling construction and demolition(C&D)wastes,presenting a low additional value.Using RP-based solidifying material can not only improve its utilization efficiency,but also reduce the cost of commercial solidifying materials.To date,this is the best solidifying material utilized to dispose the original waterworks sludge(OWS)with high moisture contents(60%),and the product could be used to fabricate non-fired bricks.This has become a new environment-friendly technology of“using waste to treat waste”.In this paper,the influence of different particle sizes and dosages of RP on the prepared solidifying material was studied.Besides,unconfined compression strength(UCS),volume stability,chemical composition,and heat of hydration,pore structure of the solidifying material were characterized.Then,non-fired bricks were prepared by using the solidifying material,recycled aggregate,and original waterworks sludge.The UCS and softing coefficient(SC)of the non-fired bricks were evaluated.As a result,the 28-day UCS of the solidifying material with optimal(M30)was 35.40 MPa,which could reach 84.37%of Portland cement(PC).The addition of RP increased the volume stability of the solidifying material.The addition of a large amount of RP reduced the heat flux and cumulative heat release of the solidifying material,while its porosity increased.The UCS of non-fired brick(NF20)in 28 days was 15.19 MPa and the SC after 28 days was 78.35%.In conclusion,the preparation of solidifying material using RP could be a promising approach and has a great potential in disposal of original waterworks sludge.
文摘Transport structures built throughout the period from 1960 to 1980 in permafrost regions based on the principle of permafrost preservation are subject to deformations.In many cases,the reason is a gradual change in temperature and their subgrade condition within the active zone due to the structures'technogenic impact.Design solutions for the fifty-year-old structures fail to ensure in all cases their reliable operation at the present time.The greatest danger to the reliable operation of railway lines in cold regions is uneven deformations of bridges,which are barrier places.Therefore,the solution to this problem is urgent especially due to the necessity of increase carrying capacity.The purpose of this study is to increase reliability of bridge operation in cold regions through strengthening the subgrade by reinforcement with injection of solidifying solutions.The problem of uneven deformations due to permafrost degradation is considered using the example of a railway bridge located in the northern line of the Krasnoyarsk railway.Deformations of the bridge abutments began immediately after the construction was completed and the bridge was open for traffic-since 1977.Permafrost degradation was developing more actively straight under the abutments due to higher thermal conductivity of the piles concrete.Notably,thawing intensity of frozen soils under the bridge abutments is uneven due to its orientation to the cardinal points.The analysis of archive materials and results of the geodetic survey made it possible to systematize the features of augmenting deformations of each abutment over time.The engineering-geological survey with drilling wells near the abutments ensured determination of soil characteristics,both in the frozen and thawed states.Thermometric wells were arranged to measure temperatures.The analysis and systematization of the data obtained allowed us to develop geotechnical models for each abutment of the bridge.The peculiarity of these models is allowance for changes in the strength and deformation characteristics of the soil calculated layers depending on changes in temperature and the soil condition.Thus,different calculated geological elements with the corresponding strength and deformation characteristics were identified in the soil layers of the same origin.The analysis of the systematized geodetic data allowed us to confirm adequacy of the developed geotechnical models.Studies carried out using geotechnical models made it possible to predict improvement of physical and mechanical characteristics of the subgrade to prevent further growth deformations of the bridge abutments.The method of reinforcement by injection is proposed.Injecting a solution under pressure leads to strengthening of weakened thawed soils and improving their physical and mechanical properties.This research theoretically substantiates and develops the geotechnical models of the reinforced pier footing of bridge abutments by injection of solidifying solutions.The models take into account the reinforcement parameters and elements for the case in question.The influence of reinforcement on the change in physical and mechanical properties of the soil mass is determined.
文摘High-water material, tailings from goldmine and water are mixed into a new slurry.Testing of rheological properties of stowing slurries A and B is made to determine type and rheological parameters of the slurry. The main factors influencing rheological properties of the slurry are analyzed and the rational concentration and empirical resistance calculating formula of pipe line transportation are presented.
基金Supported by the National Natural Science Foundation of China (No.80172842)Shanghai Municipal Fund of Natural Sciences (No.11ZR1423500)the Shanghai Municipal Health Bureau Fund for Traditional Chinese Medicine Research(No.2010L70A)
文摘Children recurrent respiratory infection （CRRI） indicates that children suffer from frequent infections along the upper or lower respiratory tract for a certain number of times. It is not an independent disease but a clinical syndrome mostly brought about by some basic diseases such as nonspecific immunity, specific immune suppression or deficiency disease, congenital bronchopulmonary dysplasia, vitamin or microelement deficiency, or is induced by some factors such as smoking, cross infection, and nursing errors.（2） Clinically, CRRI is commonly treated by anti-infective agents, symptomatic and supportive treatment, and immune-regulatory therapy. However, the therapeutic effectiveness is always imperfect, which could even lead to a premium on asthma, or nephritis, etc.
基金Funded by the National Nature Science Foundation of China(Nos.51978439,52278269,52278268,and 52108238)the Tianjin Outstanding Young Scholars Science Fund Project(No.22JCJQJC00020)the State Key Laboratory of Green Building Materials Open Foundation(No.2021GBM08)。
文摘We examined the enhancing effects of different dosages of product of Centrifugation of Bacterial Liquid(product of CBL)on the performance of slag-fGD gypsum-cement-bentonite-sludge system using MICP technology.We analyzed the multifaceted performance of the solidified sludge from macroscopic and microscopic perspectives.The experimental results reveal that the increase in product of CBL dosage results in positive impacts on the solidified sludge,including higher side compressive strength,lower leachate heavy metal concentration,and improved crack repair rates.At a 0.4%product of CBL doping concentration,the strength of the solidified sludge is enhanced by 26.6%at 3 d,61.2%at 7 d,and 13.9%at 28 d when compared to the unmodified solidified sludge.After 28 days,the concentrations of Zn and Cu ions reduce by 58%and 18%,respectively,and the crack repair rate is 58.4%.These results demonstrate that the increase in heavy metal concentration in the leachate leads to an increase in the strength of the solidified sludge.The strengthening procedure heavily relies on the mineralisation reaction of Bacillus pasteurii,which produces a substantial amount of CaCO_(3)to cement the particles and fill the pores initially.The modified solidifying sludge exhibits a self-repairing effect and an enhanced multifaceted performance as a result of oxygen being restored after crack formation and reactivation of Bacillus pasteurii.Such conditions facilitate the body's recovery.
基金financially supported by the National Natural Science Foundation of China(Nos.52175284 and 52474396)the National Key Research and Development Program of China(No.2022YFB3404201)。
文摘High pressure die casting(HPDC)AlSi10Mn Mg alloy castings are widely used in the automobile industry.Mg can optimize the mechanical properties of castings through heat treatment,while the release of thermal stress arouses the deformation of large integrated die-castings.Herein,the development of non-heat treatment Al alloys is becoming the hot topic.In addition,HPDC contains externally solidified crystals(ESCs),which are detrimental to the mechanical properties of castings.To achieve high strength and toughness of non-heat treatment die-casting Al-Si alloy,we used AlSi9Mn alloy as matrix with the introduction of Zr,Ti,Nb,and Ce.Their influences on ESCs and mechanical properties were systematically investigated through three-dimensional reconstruction and thermodynamic simulation.Our results reveal that the addition of Ti increased ESCs'size and porosity,while the introduction of Nb refined ESCs and decreased porosity.Meanwhile,large-sized Al_3(Zr,Ti)phases formed and degraded the mechanical properties.Subsequent introduction of Ce resulted in the poisoning effect and reduced mechanical properties.
文摘Living organisms have developed their unique strategies during the natural evolution for building hard tissues with minerals,including silica,calcium carbonate,calcium phosphate,and ferric oxide [1].Such biomineralized materials generally have complex hierarchical structures with excellent mechanical properties.Although bioinspired approaches have led to the creation of well-defined synthetic structural materials ranging from micro to macro scales,the rational design of discrete biomimetic structures at the nanoscale remains a grand challenge.
基金funded by the Natural Science Foundation of Inner Mongolia Autonomous Region(2023JQ03,2023QN05014)the Youth Science and Technology Talents Project of Autonomous Region Colleges and Universities(NJYT22108)。
文摘Loess slopes in cold and arid regions are susceptible to shallow soil degradation,which may trigger severe environmental problems related to soil erosion.To address this environmental challenge,this study selected a compound ecological curing agent composed of gellan gum and guar gum for stabilizing shallow loess slopes.Triaxial compression and disintegration tests were employed to comparatively analyze the effects of compound gum content,mass mix ratio,and curing age on the mechanical and disintegration properties of solidified loess.The curing mechanism was analyzed using scanning electron microscopy(SEM),and the ecological protection effect was monitored for a 60-day period.The results indicate that gellan gum,guar gum,and the compound gum can enhance the mechanical and disintegration properties of loess,promote plant growth,and optimize the ecological environment.However,the combination of gellan gum and guar gum proves more effective than using either gellan gum or guar gum alone.Considering the effects on mechanical properties,disintegration performance,and material economy,the disintegration rate of loess decreases by 75.72%compared to plain loess when the compound glue content is 0.5%,the mixing ratio of gellan gum to guar gum is 3:7 and the curing age is 7 days.Meanwhile,the cohesion and internal friction angle increase by 118.06%and 10.97%,respectively.Moreover,the disintegration performance and mechanical properties of the samples first increase and then decrease with the increase in compound glue and the mix ratio and are basically stabilized after the curing age reaches 7d.
基金the financial support of National Key Research and Development Plan(No.2021YFB3702000)National Natural Science of China(Nos.52074076,52174306 and U20A20272)Fundamental Research Funds for the Central Universities(Nos.N2225023 and N2425006).Author information。
文摘During the continuous casting process of low carbon steel,the solidified hook formed in the mold has great effects on the surface quality of the cast slab.Some factory experiments have been conducted to investigate the microscopic characteristics and reveal the influence of process parameters on solidified hooks.The depth of the hooks showed a positive correlation with the deflection angle,length,and oscillation mark(OM)depth,which indicates that the OM depth can serve as an approximate indicator for evaluating the depth of the solidified hooks.On the wide and narrow faces of the cast slab,the depth of the solidified hooks and the temperature distribution in the mold show opposite trends,with lower depths of solidified hooks at positions with higher temperatures.In addition,the influence of process parameters on solidified hooks was analyzed.With the increase in superheat,not only the depth of solidified hooks gradually decreases,but also the ratio of depression-typed marks increases.Increasing casting speed and decreasing immersion depth of the submerged entry nozzle will both lead to a decrease in the depth of the solidified hook.
基金Funded by the China Construction Shares Technology Research and Development Project(No.CSCEC-2023-Z-07)CSCEC Strait Major Scientific and Technological Project(No.ZJHX2023C001)+1 种基金Engineering Research Center of Prevention and Control of Geological Disasters in the Mountainous Areas of Northern Fujian,Fujian Province University,China(No.WYERC2024-3)Science s of Fujian Province(No.2023J01476)。
文摘Fluidized solidified soil(FSS)is an innovative backfill material that offers benefits such as easy pumping and straightforward construction.This study examined how varying the water-soil ratio and the curing agent dosage affect the properties and microstructure of FSS.The strength development mechanism was investigated when composite solidification agents were used.The findings show that both the water-solid ratio and the curing agent dosage can affect the microstructure of FSS,thereby affecting its performance.When the water-solid ratio increases from 0.52 to 0.56,the unconfined compressive strength(UCS)and flexural strength of the FSS decrease by 34.1% and 39.3% after 28 d.Conversely,the curing agent dosage increasing from 10% to 30% will increase both UCS and flexural strength by 11.2 times and 11.1 times.As the curing age increases,the number of cracks at failure point in the FSS will increase and lead to a more complete failure.Numerous needle-like AFt,C-S-H gel,and C-(A)-S-H gel create a three-dimensional network by adhering to soil particles.
基金financially supported by the National Key Research and Development Program of China(2022YFB3404201)the Major Science and Technology Project of Changchun City,Jilin Province(Grant No.20210301024GX)。
文摘The effect of slow shot speed on externally solidified crystal(ESC),porosity and tensile property in a newly developed high-pressure die-cast Al-Si alloy was investigated by optical microscopy(OM),scanning electron microscopy(SEM)and laboratory computed tomography(CT).Results showed that the newly developed AlSi9MnMoV alloy exhibited improved mechanical properties when compared to the AlSi10MnMg alloy.The AlSi9MnMoV alloy,which was designed with trace multicomponent additions,displays a notable grain refining effect in comparison to the AlSi10MnMg alloy.Refining elements Ti,Zr,V,Nb,B promote heterogeneous nucleation and reduce the grain size of primaryα-Al.At a lower slow shot speed,the large ESCs are easier to form and gather,developing into the dendrite net and net-shrinkage.With an increase in slow shot speed,the size and number of ESCs and porosities significantly reduce.In addition,the distribution of ESCs is more dispersed and the net-shrinkage disappears.The tensile property is greatly improved by adopting a higher slow shot speed.The ultimate tensile strength is enhanced from 260.31 MPa to 290.31 MPa(increased by 11.52%),and the elongation is enhanced from 3.72%to 6.34%(increased by 70.52%).
基金supported by the National Key R&D Program of China(No.2021YFB3803004)the National Natural Science Foundation of China(Nos.52101239 and 52171153)+4 种基金Ningbo Natural Science Foundation(No.2021J222)the“Pioneer”R&D Program of Zhejiang Province(No.2023C01075)Youth Innovation Promotion Association CAS(No.2021294)Zhejiang Provincial Key Research and Development Projects(No.2021C01033)CITIC Group Major Science and Technology Innovation Project(HT-FZB-2022190).
文摘Unique rapid solidified structure and nanocrystallization mechanism enable the Fe-based nanocrystalline alloys with high Cu content excellent soft magnetic properties and good manufacturability,and also results in unusual phenomena in terms of alloying effects.In the present work,we systematically studied the influence rules of early transition elements on the rapid solidified structure and nanocrystallization behaviors of Fe-Si-B-Cu soft magnetic alloys with high Cu content and explored the related mechanisms.In terms of rapid solidified structure,the additions of early transition elements always inhibit the for-mation of pre-existingα-Fe crystals even eliminate them,and the additions that could produce larger atomic mismatch parameter(δ)and negative mixing enthalpy(△H_(mix))show stronger effects.In terms of nanocrystallization behaviors,the increases inδand negative△H_(mix) weaken the competitive growth between the pre-existing nanocrystals during annealing and then coarsen the nanostructure of the an-nealed alloys and deteriorate their magnetic softness,while the excessive increases inδand negativeHmix could significantly suppress the growth ofα-Fe crystals by diffusion inhibition during annealing and thus remarkable refine the nanostructure of the annealed alloys and improve their magnetic softness.
基金financially supported by the Science and Technology Commission Foundation of Shanghai(Grant Nos.22DZ1208903,20DZ2251900)the National Natural Science Foundation of China(Grant No.51679134)。
文摘A new scour countermeasure using solidified slurry for offshore foundation has been proposed recently.Fluidized solidified slurry is pumped to seabed area around foundation for scour protection or pumped into the developed scour holes for scour repair as the fluidized material solidifies gradually.In the pumping operation and solidification,the engineering behaviors of solidified slurry require to be considered synthetically for the reliable application in scour repair and protection of ocean engineering such as the pumpability related flow value,flow diffusion behavior related rheological property,anti-scour performance related retention rate in solidification and bearing capacity related strength property after solidification.In this study,a series of laboratory tests are conducted to investigate the effects of mix proportion(initial water content and binder content)on the flow value,rheological properties,density,retention rate of solidified slurry and unconfined compressive strength(UCS).The results reveal that the flow value increases with the water content and decreases with the binder amount.All the solidified slurry exhibits Bingham plastic behavior when the shear rate is larger than 5 s^(-1).The Bingham model has been employed to fit the rheology test results,and empirical formulas for obtaining the density,yield stress and viscosity are established,providing scientific support for the numerical assessment of flow and diffusion of solidified slurry.Retention rate of solidified slurry decreases with the water flow velocity and flow value,which means the pumpability of solidified slurry is contrary to anti-scour performance.The unconfined compressive strength after solidification reduces as the water content increases and binder content decreases.A design and application procedure of solidified soil for scour repair and protection is also proposed for engineering reference.
基金financially supported by the National Natural Science Foundation of China(Nos.52201082 and 51971139)the Science Center for Gas Turbine Project(No.P2022-A-I-002-001)+1 种基金the Shanghai Sailing Program(No.22YF1419200)sponsored by the Chenguang Program supported by Shanghai Education Development Foundation and Shanghai Municipal Education Commission(No.21CGA10).
文摘The oxidation and interdiffusion behavior of a novel AlCoCrFeNiY bond coat deposited on a directionally solidified Ni-based superalloy were systematically studied at 1050,1100 and 1150°C,and compared with a conventional NiCoCrAlY coating deposited on the same substrate.The AlCoCrFeNiY bond coat exhibits lower oxide growth rates due to its large columnar grains and low Al activity at the oxide scale/bond coat interface.Meanwhile,AlCoCrFeNiY has higher resistance to oxide spallation than NiCoCrAlY,which is attributed to the formation of a clean and defect-free metal/oxide interface.Significant interdiffusion occurs across the AlCoCrFeNiY/superalloy substrate interface.Our experimental evidence and thermody-namic modelling suggest that Fe accelerates interdiffusion and destabilizes theγ’phase,thereby causing the formation of a thick andγ’-depleted interdiffusion zone.In addition,the AlCoCrFeNiY bond coat un-dergoes more Al depletion and subsequentβtoγtransformation compared with NiCoCrAlY.Based on the findings in this work,a novel AlCoCrFeNiY/NiCoCrAlY double-layer bond coat was designed,tested and validated to achieve optimal balance between oxidation and interdiffusion.
