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
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
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
Sand production and high water content in oil wells are two major challenges that restrict high and stable production in loose sandstone reservoirs.In this paper,nano SiO_(2),coupling agent triethoxysilane,phenolic re...Sand production and high water content in oil wells are two major challenges that restrict high and stable production in loose sandstone reservoirs.In this paper,nano SiO_(2),coupling agent triethoxysilane,phenolic resin and n-octanol were used to synthesize the main agent SCA-2.Hexamethylenetetramine and vinyl carbonate were selected to prepare the curing agent YGA-1,which was then compounded with SCA-2 to develop a sand fixation and water plugging system.Firstly,single-factor experiments were conducted to determine the optimal concentrations of SCA-2 and YGA-1,subsequently,the system’s sand fixation and water blocking performance were evaluated.Finally,a pilot test was carried out in the mining site.Experimental results showed that the optimal formula composition of the system was 10%SCA-2+5%YGA-1.The gelation time of the system was 180 minutes and the viscosity after gelation could reach 108.4 mPa·s.When the dosage of the drug system was 0.6 PV,the sand production rate remained below 0.08%.Dual-tube parallel experiments showed that the sand fixation and water plugging system had a water flow channel plugging rate of 87.5%,while the oil flow channel plugging rate was only 11.3%,indicating minimal damage to the oil-bearing reservoir.The field test showed that after the measures taken in Well M of X oilfield,the sand free oil recovery period exceeded 360 days,the water content decreased by 5.0%and the cumulative oil production increased by 7092 m^(3).This study provides new ideas for efficient development of loose sandstone reservoirs.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 effects of vacuum assistance on the microstructure and mechanical properties of high-pressure die cast AZ91 D alloy at different slow shot speeds were evaluated. Plate-shaped castings of AZ91 D alloy were carried ...The effects of vacuum assistance on the microstructure and mechanical properties of high-pressure die cast AZ91 D alloy at different slow shot speeds were evaluated. Plate-shaped castings of AZ91 D alloy were carried out on a TOYO BD-350V5 cold chamber die casting machine incorporated with a self-improved TOYO vacuum system. It was found that the vacuum pressure in the die cavity at the beginning of mold filling increases with the increase of slow shot speed, following a cubic polynomial curve, resulting in a decline in the porosity-reduction ability of vacuum assistance with the increase of slow shot speed. The externally solidified crystal（ESC） contents in conventional and vacuum die castings behave similar against the slow shot speed. The tensile properties of vacuum die castings were strongly influenced by the ESC content at relative low slow shot speeds. With the increase of slow shot speed, the influence of the gas porosity level in vacuum die castings would get prominent.展开更多
Standard mechanical test bars with a diameter of 6.4 mm and a gauge length of 50 mm were processed, and the microstructures of die cast AM60B alloy under different die casting process parameters were observed. The inf...Standard mechanical test bars with a diameter of 6.4 mm and a gauge length of 50 mm were processed, and the microstructures of die cast AM60B alloy under different die casting process parameters were observed. The influences of the slow shot speed, the fast shot speed and the biscuit thickness on the externally solidified crystals （ESCs） were investigated. With the increase of the biscuit thickness, the number of the ESCs in the cast samples decreases. Under a low slow shot speed, larg ESCs are found in the cast structure and a high fast shot speed results in more spherical ESCs. The relationships between ESCs and process parameters were also discussed.展开更多
Two multi-step （two-step and three-step） slow shot speeds were used in the vacuum die casting process of AZ91D magnesium alloy. The vacuum pressure variation in the die cavity before mold filling was monitored by us...Two multi-step （two-step and three-step） slow shot speeds were used in the vacuum die casting process of AZ91D magnesium alloy. The vacuum pressure variation in the die cavity before mold filling was monitored by using a pressure sensor. The microstructures of the produced castings were analyzed with optical microscope and image analysis software. The experimental results demonstrate that, the vacuum pressure in the die cavity at the beginning of mold filling is significantly reduced by using three-step slow shot speed, resulting in a low gas porosity level in the produced castings. At an appropriate multi-step slow shot speed, the dwell time of the liquid metal in the shot sleeve before mold filling can be reduced and the flow of the liquid metal in the shot sleeve at the later stage of the slow shot process can be restrained, which cause a low externally solidified crystal content in the produced castings.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.
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 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Sand production and high water content in oil wells are two major challenges that restrict high and stable production in loose sandstone reservoirs.In this paper,nano SiO_(2),coupling agent triethoxysilane,phenolic resin and n-octanol were used to synthesize the main agent SCA-2.Hexamethylenetetramine and vinyl carbonate were selected to prepare the curing agent YGA-1,which was then compounded with SCA-2 to develop a sand fixation and water plugging system.Firstly,single-factor experiments were conducted to determine the optimal concentrations of SCA-2 and YGA-1,subsequently,the system’s sand fixation and water blocking performance were evaluated.Finally,a pilot test was carried out in the mining site.Experimental results showed that the optimal formula composition of the system was 10%SCA-2+5%YGA-1.The gelation time of the system was 180 minutes and the viscosity after gelation could reach 108.4 mPa·s.When the dosage of the drug system was 0.6 PV,the sand production rate remained below 0.08%.Dual-tube parallel experiments showed that the sand fixation and water plugging system had a water flow channel plugging rate of 87.5%,while the oil flow channel plugging rate was only 11.3%,indicating minimal damage to the oil-bearing reservoir.The field test showed that after the measures taken in Well M of X oilfield,the sand free oil recovery period exceeded 360 days,the water content decreased by 5.0%and the cumulative oil production increased by 7092 m^(3).This study provides new ideas for efficient development of loose sandstone reservoirs.
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Project(2012ZX04012011)supported by the National Science and Technology Major Project of the Ministry of Science and Technology of ChinaProject(2011BAE22B02)supported by the National Key Technologies R&D Program of ChinaProject(51275269)supported by the National Natural Science Foundation of China
文摘The effects of vacuum assistance on the microstructure and mechanical properties of high-pressure die cast AZ91 D alloy at different slow shot speeds were evaluated. Plate-shaped castings of AZ91 D alloy were carried out on a TOYO BD-350V5 cold chamber die casting machine incorporated with a self-improved TOYO vacuum system. It was found that the vacuum pressure in the die cavity at the beginning of mold filling increases with the increase of slow shot speed, following a cubic polynomial curve, resulting in a decline in the porosity-reduction ability of vacuum assistance with the increase of slow shot speed. The externally solidified crystal（ESC） contents in conventional and vacuum die castings behave similar against the slow shot speed. The tensile properties of vacuum die castings were strongly influenced by the ESC content at relative low slow shot speeds. With the increase of slow shot speed, the influence of the gas porosity level in vacuum die castings would get prominent.
基金Project(2009AA03Z114)supported by the National High-tech Research and Development Program of ChinaProject supported by Tsinghua-Toyo R&D Center of Magnesium and Aluminum Alloys Processing Technology
文摘Standard mechanical test bars with a diameter of 6.4 mm and a gauge length of 50 mm were processed, and the microstructures of die cast AM60B alloy under different die casting process parameters were observed. The influences of the slow shot speed, the fast shot speed and the biscuit thickness on the externally solidified crystals （ESCs） were investigated. With the increase of the biscuit thickness, the number of the ESCs in the cast samples decreases. Under a low slow shot speed, larg ESCs are found in the cast structure and a high fast shot speed results in more spherical ESCs. The relationships between ESCs and process parameters were also discussed.
基金Project(51275269)supported by the National Natural Science Foundation of ChinaProject(20121087918)supported by the Independent Research Program,China+1 种基金Project(2012ZX04012011)supported by the National Science and Technology Major Project of the Ministry of Science and Technology of ChinaProject(2013M540936)supported by Postdoctoral Science Foundation of China
文摘Two multi-step （two-step and three-step） slow shot speeds were used in the vacuum die casting process of AZ91D magnesium alloy. The vacuum pressure variation in the die cavity before mold filling was monitored by using a pressure sensor. The microstructures of the produced castings were analyzed with optical microscope and image analysis software. The experimental results demonstrate that, the vacuum pressure in the die cavity at the beginning of mold filling is significantly reduced by using three-step slow shot speed, resulting in a low gas porosity level in the produced castings. At an appropriate multi-step slow shot speed, the dwell time of the liquid metal in the shot sleeve before mold filling can be reduced and the flow of the liquid metal in the shot sleeve at the later stage of the slow shot process can be restrained, which cause a low externally solidified crystal content in the produced castings.
