The active development of space industry necessitates the cre-ation of novel materials with unique properties,including shape memory alloys(SMAs).The development of ultra-high temperature SMAs(UHTSMAs)with operating t...The active development of space industry necessitates the cre-ation of novel materials with unique properties,including shape memory alloys(SMAs).The development of ultra-high temperature SMAs(UHTSMAs)with operating temperatures above 400℃is a significant challenge[1-3].It is known that reversible thermoelas-tic martensitic transformation(MT)is the basis for shape mem-ory behavior[4].Currently,there are several systems in which MT temperatures meet the above requirements,for example,RuNb[5],HfPd[6],TiPd[7].展开更多
Whilst phosphorus(P)in soil is considered to be abundant,the portion available for plant uptake constitutes less than 1%of the overall P present.To enhance crop productivity,the utilization of mineral P fertilizers ha...Whilst phosphorus(P)in soil is considered to be abundant,the portion available for plant uptake constitutes less than 1%of the overall P present.To enhance crop productivity,the utilization of mineral P fertilizers has become pervasive in agriculture.Nonetheless,the escalating prices of chemical fertilizers,coupled with new European regulations prohibiting the use of P fertilizers containing cadmium,have highlighted the urgency to identify environmentally friendly products and practices for P fertilization in agricultural soils.This comprehensive review delves into the current landscape of P fertilization from agricultural,political,and economic standpoints.We recognize the potential of microbes in mobilizing P,but emphasize the necessity for more robust research to establish their effectiveness in promoting plant P uptake under real-world conditions.Additionally,we explore the role of agricultural conservation practices,such as optimal tillage,diversified cropping systems,and increased organic carbon input,in conserving P.Furthermore,this review contemplates forthcoming innovations in research.These innovations encompass the development of enhanced formulations for biofertilizers and the undertaking of more comprehensive studies within the realm of conservation agriculture.All these endeavors collectively hold the potential to augment P accessibility to plants in a sustainable manner,thereby advancing agricultural sustainability and productivity.展开更多
To improve the oxidation resistance of HfB_(2)-SiC coatings on carbon/carbon composites at 1700°C in air,CeO_(2) was introduced to improve oxygen blocking and its mechanism was investigated.During the rapid oxida...To improve the oxidation resistance of HfB_(2)-SiC coatings on carbon/carbon composites at 1700°C in air,CeO_(2) was introduced to improve oxygen blocking and its mechanism was investigated.During the rapid oxidation stage,CeO_(2) accelerated the formation of a multiphase glass layer on the coating surface.The maximum oxidation rates of CeO_(2)-HfB2-SiC coatings with 1%,3%,and 5%CeO_(2) were 24.1%,20.3%,and 53.2%higher than that of the unmodified HfB2-SiC coating,respectively.In the stable oxidation stage,the maximum oxidation rates of coatings with 1%and 3%CeO_(2) decreased by 31.4%and 21.9%,respectively,demonstrating adequate inert protection.CeO_(2) is a“coagulant”and“stabilizer”in the composite glass layer.However,increasing the CeO_(2) content accelerates the reaction between the SiO_(2) glass phase and SiC,leading to a higher SiO_(2) consumption and reduced self-healing ability of the glass layer.The 1%CeO_(2)-60%HfB2-39%SiC coating showed improved glass layer viscosity and stability,moderate SiO_(2) consumption,and better self-healing ability,significantly boosting the oxidation protection of the coating.展开更多
The majority of industrial aluminum casting alloys exhibit low thermal conductivity,which is insufficient for effective heat transfer in electronic devices.The objective of this investigation was to develop new alumin...The majority of industrial aluminum casting alloys exhibit low thermal conductivity,which is insufficient for effective heat transfer in electronic devices.The objective of this investigation was to develop new aluminum casting alloys with high thermal conductivity.The impact of alloying elements on the thermal conductivity of pure aluminum was examined,and the relationships among microstructure,thermal conductivity,and the mechanical and corrosion properties of Al-Zn-Ca-(Cu,Mg)alloys were explored.The findings indicate that in the as-cast state,the structure of the alloys consists ofα-Al and a eutectic containing the(Al,Zn)4Ca phase.Following the solution heat treatment,the(Al,Zn)4Ca phase is spheroidised,and thermal conductivity of the alloys increases,reaching over 75%that of pure aluminum.However,the heat-treated alloys exhibit low mechanical properties:tensile yield strength<60 MPa,ultimate tensile strength<160 MPa,and elongation at fracture>15%.The alloys demonstrate satisfactory fluidity and low hot tearing susceptibility.With the exception of the alloy containing copper,the alloys exhibit low corrosion rates,estimated at approximately 0.02 mm/a.展开更多
The paper contains the results of investigation of interconnections between coals’vitrinite structural features,mode of its crushing under the cyclic nanoindentation with increasing peak load and coals’proneness to ...The paper contains the results of investigation of interconnections between coals’vitrinite structural features,mode of its crushing under the cyclic nanoindentation with increasing peak load and coals’proneness to formation of airborne respirable dust(ARD)with particles sized<10μm(PM10).A specific value of PM10 contents in coals normalized on a fines fraction(with particles sizes of less than 200μm)was used as a measure of proneness to ARD formation.It has been shown that the aforementioned parameter is predefined by the ratio of amorphous and crystalline carbon compounds in vitrinite and the mode of its crushing.Some preliminary investigation have been done in order to characterize the involvement of inertinite in ARD formation.It was proposed that the inertinite is not as actively involved in the processes of ARD formation of coals as vitrinite,having a more diverse structural features in terms of amorphous to crystalline carbon compounds ratio.展开更多
A parametrization of density matrices of ddimensions in terms of the raising J+and lowering J−angular momentum operators is established together with an implicit connection with the generalized Bloch-GellMann paramete...A parametrization of density matrices of ddimensions in terms of the raising J+and lowering J−angular momentum operators is established together with an implicit connection with the generalized Bloch-GellMann parameters. A general expression for the density matrix of the composite system of angular momenta j1and j2is obtained. In this matrix representation violations of the Bell-Clauser-Horne-Shimony-Holt inequalities are established for the X-states of a qubit-qubit, pure and mixed, composite system, as well as for a qubit-qutrit density matrix. In both cases maximal violation of the Bell inequalities can be reached, i.e., the Cirel’son limit. A correlation between the entanglement measure and a strong violation of the Bell factor is also given. For the qubit-qutrit composite system a time-dependent convex combination of the density matrix of the eigenstates of a two-particle Hamiltonian system is used to determine periodic maximal violations of the Bell’s inequality.展开更多
The development of actuators based on ionic polymers as soft robotics,artificial muscles,and sensors is currently considered one of the most urgent topics.They are lightweight materials,in addition to their high effic...The development of actuators based on ionic polymers as soft robotics,artificial muscles,and sensors is currently considered one of the most urgent topics.They are lightweight materials,in addition to their high efficiency,and they can be controlled by a low power source.Nevertheless,the most popular ionic polymers are derived from fossil-based resources.Hence,it is now deemed crucial to produce these actuators using sustainable materials.In this review,the use of ionic polymeric materials as actuators is reviewed through the emphasis on their role in the domain of renewablematerials.The reviewencompasses recent advancements inmaterial formulation and performance enhancement,alongside a comparative analysis with conventional actuator systems.It was found that renewable polymeric actuators based on ionic gels and conductive polymers are easier to prepare compared to ionic polymermetal composites.In addition,the proportion of actuator manufacturing utilizing renewable materials rose to 90%,particularly for ion gel actuators,which was related to the possibility of using renewable polymers as ionic or conductive substances.Moreover,the possible improvements in biopolymeric actuators will experience an annual rise of at least 10%over the next decade,correlating with the growth of their market,which aligns with the worldwide goal of reducing global warming.Additionally,compared to fossil-derived polymers,the decomposition rate of renewable materials reaches 100%,while biodegradable fossil-based substances can exceed 60%within several weeks.Ultimately,this review aims to elucidate the potential of ionic polymeric materials as a viable and sustainable solution for future actuator technologies.展开更多
A study of the effect of rotary swaging(RS)at 350℃ on mechanical properties,corrosion resistance and biocompatibility in vitro and in vivo of biodegradable Mg-1%Zn-0.6%Ca alloy was conducted.It is shown that the form...A study of the effect of rotary swaging(RS)at 350℃ on mechanical properties,corrosion resistance and biocompatibility in vitro and in vivo of biodegradable Mg-1%Zn-0.6%Ca alloy was conducted.It is shown that the formation of a recrystallized microstructure after RS with a grain size of 3.2±0.2μm leads to an increase in the strength of the alloy without reduction of level of ductility and corrosion resistance.At the same time,aging of the quenched alloy at 100℃ for 8 h leads to a slight increase in strength,but significantly reduces its ductility and corrosion resistance.The study of the degradation process of the alloy in the quenched state and after RS,both under in vitro and in vivo conditions,did not reveal a significant difference between these two microstructural states.However,an increase in the duration of incubation of the alloy in a complete growth medium from 4 h to 24 days leads to a decrease in the degradation rate(DR)by 4times(from~2 to~0.5 mm/year)due to the formation of a dense layer of degradation products.The study of biocompatibility in vitro did not reveal a significant effect of RS on the hemolytic and cytotoxic activity of the alloy.No signs of systemic toxicity were observed after subcutaneous implantation of alloy samples into mice before and after RS.However,it was found that RS promotes uniform degradation of the alloy over the entire contact surface.In summary,RS at 350℃ allows to increase the strength of Mg-1%Zn-0.6%Ca alloy up to348±5 MPa at a ductility level of 17.3±2.8%and a DRin vivoequal to 0.56±0.12 mm/year without impairing its biocompatibility in vitro and in vivo.展开更多
Zn is a commonly used alloying element for Mg alloys owing to its beneficial effects on mechanical properties. To improve the mechanical and corrosion properties of WE43B Mg alloys, the effects of 0–0.7wt% Zn additio...Zn is a commonly used alloying element for Mg alloys owing to its beneficial effects on mechanical properties. To improve the mechanical and corrosion properties of WE43B Mg alloys, the effects of 0–0.7wt% Zn addition on the microstructure and properties of sample alloys were investigated. Addition of Zn to as-cast WE43B alloy promoted the formation of the Mg12Nd phase;by contrast, after T6 heat treatment, the phase composition of WE43B alloys with and without Zn addition remained mostly the same. A long-period stacking ordered phase was predicted by CALPHAD calculation, but this phase was not observed in either the as-cast or heat-treated Zn-containing WE43B alloys. The optimum temperature and duration of T6 heat treatment were obtained using CALPHAD calculations and hardness measurements. Addition of Zn resulted in a slight reduction in the average grain size of the as-cast and T6 heat-treated WE43B alloys and endowed them with increased corrosion resistance with little effect on their mechanical properties.展开更多
Biodegradable Mg-based implants are widely used in clinical applications because they exhibit mechanical properties comparable to those of human bone and require no revision surgery for their removal.Among Mg-based al...Biodegradable Mg-based implants are widely used in clinical applications because they exhibit mechanical properties comparable to those of human bone and require no revision surgery for their removal.Among Mg-based alloys,Mg–Zn–Ca–(Mn)alloys have been extensively investigated for medical applications because the constituent elements of these alloys,Mg,Zn,Ca,and Mn,are present in human tissues as nutrient elements.In this study,we investigated the effect of the hot extrusion temperature on the microstructure,mechanical properties,and biodegradation rate of Mg–Zn–Ca–(Mn)alloys.The results showed that the addition of Mn and a decrease in the extrusion temperature resulted in grain refinement followed by an increase in the strength and a decrease in the elongation at fracture of the alloys.The alloys showed different mechanical properties along the directions parallel and perpendicular to the extrusion direction.The corrosion test of the alloys in the Hanks’solution revealed that the addition of Mn significantly reduced the corrosion rate of the alloys.The Mg–2 wt%Zn–0.7 wt%Ca–1 wt%Mn alloy hot-extruded at 300℃ with an ultimate tensile strength of 278MPa,an yield strength of 229MPa,an elongation at fracture of 10%,and a corrosion rate of 0.3 mm/year was found to be suitable for orthopedic implants.展开更多
The microstructure and mechanical properties of novel Al-Y-Sc alloys with high thermal stability and electrical conductivity were investigated.Eutectic Al3 Y-phase particles of size 100-200 nm were detected in the as-...The microstructure and mechanical properties of novel Al-Y-Sc alloys with high thermal stability and electrical conductivity were investigated.Eutectic Al3 Y-phase particles of size 100-200 nm were detected in the as-cast microstructure of the alloys.Al3 Y-phase particles provided a higher hardness to as cast alloys than homogenized alloys in the temperature range of 370-440℃.L12 precipitates of the Al3(ScxYy) phase were nucleated homogenously within the aluminium matrix and heterogeneously on the dislocations during annealing at 400℃.The average size of the L12 precipitates was 11±2 nm after annealing for 1 h,and 25-30 nm after annealing for 5 h,which led to a decrease in the hardness of the Al-0.2 Y-0.2 Sc alloy to15 HV.The recrystallization temperature exceeded 350℃and 450℃for the Al-0.2 Y-0.05 Sc and Al-0.2 Y-0.2 Sc alloys,respectively.The investigated alloys demonstrated good thermal stability of the hardness and tensile properties after annealing the rolled alloys at 200 and 300℃,due to fixing of the dislocations and grain boundaries by L12 precipitates and eutectic Al3 Y-phase particles.The good combination of strength,plasticity,and electrical conductivity of the investigated Al-0.2 Y-0.2 Sc alloys make it a promising candidate for electrical conductors.The alloys exhibited a yield stress of 177-183 MPa,ultimate tensile stress of 199-202 MPa,elongation of 15.2-15.8%,and electrical conductivity of 60.8%-61.5% IACS.展开更多
Traditional methods of coal thermal resistance characterization are informative but considerably timeconsuming and require utilization of a complex and expensive equipment. This limits the effectiveness of their appli...Traditional methods of coal thermal resistance characterization are informative but considerably timeconsuming and require utilization of a complex and expensive equipment. This limits the effectiveness of their application. In this paper, authors experimentally investigated potential application of thermally stimulated acoustic emission method for developing of relatively simple and rapid coals thermal resistance assessment method. Features of thermally stimulated acoustic emission of anthracite, lignites and bituminous coal samples subject to cyclic thermal loading have been experimentally investigated.For the first time, it has been shown that there exists a relationship of such patterns with structural parameters and properties of the coal samples, as well as their thermal resistance. The results indicate the possibility of applying the method of thermally stimulated acoustic emission to control processes of cryogenic disintegration and thermal resistance of fossil coals. The description of the equipment and methodological support needed for the implementation of this method have been provided.展开更多
Tribological behaviors of monolithic A356 aluminum alloy castings and A356.CNT nanocomposite castings, fabricated by fully liquid and semisolid routes were examined. Samples were prepared by melt agitation, rheocastin...Tribological behaviors of monolithic A356 aluminum alloy castings and A356.CNT nanocomposite castings, fabricated by fully liquid and semisolid routes were examined. Samples were prepared by melt agitation, rheocasting, stir casting, and compocasting techniques. Effects of addition of carbon nanotubes (CNTs), casting process and the applied load on wear properties and mechanisms were investigated. It was found that wear loss, wear rate and friction coefficient of nanocomposite samples remarkably declined by the addition of CNTs. Moreover, changing the casting process from fully liquid to semisolid routes, plus increasing fractions of the primary phase were the two factors that improved the wear properties of the investigated samples, especially nanocomposite ones. In addition, it was revealed that adhesion and delamination were the dominant wear mechanism of the monolithic samples produced by fully liquid and semisolid routes, respectively. However, regardless of fabrication techniques, the abrasion was the main wear mechanism of nanocomposite samples.展开更多
Magnesium alloys are used in aircraft because of their light weight.However,for these alloys to be applied in electronic devices,high thermal conductivities are required.Several high-potential compositions of Mg-Zn-Y-...Magnesium alloys are used in aircraft because of their light weight.However,for these alloys to be applied in electronic devices,high thermal conductivities are required.Several high-potential compositions of Mg-Zn-Y-Zr alloys were selected by phase composition and their freezing ranges calculated using Thermo-Calc software.The alloys were prepared,and their fluidity,hot tearing susceptibility,mechanical properties,and thermal conductivity were obtained and compared.The alloy composed of Mg-4 wt%Zn-3 wt%Y-0.3 wt%Zr was selected for further investigation,because of its high thermal conductivity and satisfactory mechanical properties.The Mg-4 wt%Zn-3 wt%Y-0.3 wt%Zr alloy’s fluidity and hot tearing susceptibility were similar to those of the widespread AZ91 commercial casting magnesium alloy.The influence of a heat treatment regime on the microstructure,thermal conductivity,and mechanical properties of the developed alloy was also investigated.It was established that the room temperature thermal conductivity of the Mg-4 wt%Zn-3 wt%Y-0.3 wt%Zr alloy after aging at 300℃for 5 h was 105 W/m K^(-1).Additionally,the following tensile test results were obtained in aged condition:120 MPa yield strength,200 MPa ultimate tensile strength,and 4%elongation.The utilization of solid solution heat treatment at 520℃for 8 h prior to aging can promote up to 9%increase in elongation.The Mg-4 wt%Zn-3 wt%Y-0.3 wt%Zr casting alloy can be used as a high thermal conductivity material with industrial applications.展开更多
Lateral flow immunoassay(LFIA) is a widely used express method and offers advantages such as a short analysis time, simplicity of testing and result evaluation.However, an LFIA based on gold nanospheres lacks the desi...Lateral flow immunoassay(LFIA) is a widely used express method and offers advantages such as a short analysis time, simplicity of testing and result evaluation.However, an LFIA based on gold nanospheres lacks the desired sensitivity, thereby limiting its wide applications.In this study, spherical nanogold labels along with new types of nanogold labels such as gold nanopopcorns and nanostars were prepared, characterized, and applied for LFIA of model protein antigen procalcitonin. It was found that the label with a structure close to spherical provided more uniform distribution of specific antibodies on its surface, indicative of its suitability for this type of analysis.LFIA using gold nanopopcorns as a label allowed procalcitonin detection over a linear range of 0.5–10 ng mL^(-1) with the limit of detection of 0.1 ng mL^(-1), which was fivefold higher than the sensitivity of the assay with gold nanospheres. Another approach to improve the sensitivity of the assay included the silver enhancement method,which was used to compare the amplification of LFIA for procalcitonin detection. The sensitivity of procalcitonin determination by this method was 10 times better the sensitivity of the conventional LFIA with gold nanosphere as a label. The proposed approach of LFIA based on gold nanopopcorns improved the detection sensitivity without additional steps and prevented the increased consumption of specific reagents(antibodies).展开更多
Application of calcium as alloying element for magnesium alloys has been considered according to literature data.Mg–7%Al–4%Ca–0.5%Mn casting alloy was offered,which possesses the low propensity to the hot brittlene...Application of calcium as alloying element for magnesium alloys has been considered according to literature data.Mg–7%Al–4%Ca–0.5%Mn casting alloy was offered,which possesses the low propensity to the hot brittleness and good castability.The alloy has the moderate strength(σu=150 MPa)and the satisfactory percentage elongation(δ=3%).It is shown,that calcium-containing alloys smelting of Mg–Al–Ca–Mn system is preferable with the application of low-chloride flux FL10(20%MgCl_(2);29%KCl;12%BaCl_(2);23%CaF2;15%MgF2;1%B2O3).The alloy smelting in the atmosphere of argon and SF6 mixture results in the increased shelling and waste of calcium.The heat treatment is offered for the developed alloy,which is directed to the Al_(2)Ca phase spheroidizing.The developed magnesium alloy,alloyed with calcium,is perspective for the industry production of low-cost moulding.展开更多
基金supported by the National Natural Science Foundation of China(Nos.52201207 and 52271169)the Fundamental Research Funds for the Central University(No.3072024LJ1002).
文摘The active development of space industry necessitates the cre-ation of novel materials with unique properties,including shape memory alloys(SMAs).The development of ultra-high temperature SMAs(UHTSMAs)with operating temperatures above 400℃is a significant challenge[1-3].It is known that reversible thermoelas-tic martensitic transformation(MT)is the basis for shape mem-ory behavior[4].Currently,there are several systems in which MT temperatures meet the above requirements,for example,RuNb[5],HfPd[6],TiPd[7].
基金financed by the Spanish Ministry of Science and Innovation and the European Regional Development Fund(ERDF)(No.PID20211234690BI00)the European Joint Program EJP_Soil(TRACE-Soils)(No.862695)+1 种基金the Spanish Ministry of Science and Innovation(RED2018-102624TMCIN/AEI/10.13039/501100011033)the Project PREPSOIL European Union(No.101070045,HORIZON CSA)。
文摘Whilst phosphorus(P)in soil is considered to be abundant,the portion available for plant uptake constitutes less than 1%of the overall P present.To enhance crop productivity,the utilization of mineral P fertilizers has become pervasive in agriculture.Nonetheless,the escalating prices of chemical fertilizers,coupled with new European regulations prohibiting the use of P fertilizers containing cadmium,have highlighted the urgency to identify environmentally friendly products and practices for P fertilization in agricultural soils.This comprehensive review delves into the current landscape of P fertilization from agricultural,political,and economic standpoints.We recognize the potential of microbes in mobilizing P,but emphasize the necessity for more robust research to establish their effectiveness in promoting plant P uptake under real-world conditions.Additionally,we explore the role of agricultural conservation practices,such as optimal tillage,diversified cropping systems,and increased organic carbon input,in conserving P.Furthermore,this review contemplates forthcoming innovations in research.These innovations encompass the development of enhanced formulations for biofertilizers and the undertaking of more comprehensive studies within the realm of conservation agriculture.All these endeavors collectively hold the potential to augment P accessibility to plants in a sustainable manner,thereby advancing agricultural sustainability and productivity.
文摘To improve the oxidation resistance of HfB_(2)-SiC coatings on carbon/carbon composites at 1700°C in air,CeO_(2) was introduced to improve oxygen blocking and its mechanism was investigated.During the rapid oxidation stage,CeO_(2) accelerated the formation of a multiphase glass layer on the coating surface.The maximum oxidation rates of CeO_(2)-HfB2-SiC coatings with 1%,3%,and 5%CeO_(2) were 24.1%,20.3%,and 53.2%higher than that of the unmodified HfB2-SiC coating,respectively.In the stable oxidation stage,the maximum oxidation rates of coatings with 1%and 3%CeO_(2) decreased by 31.4%and 21.9%,respectively,demonstrating adequate inert protection.CeO_(2) is a“coagulant”and“stabilizer”in the composite glass layer.However,increasing the CeO_(2) content accelerates the reaction between the SiO_(2) glass phase and SiC,leading to a higher SiO_(2) consumption and reduced self-healing ability of the glass layer.The 1%CeO_(2)-60%HfB2-39%SiC coating showed improved glass layer viscosity and stability,moderate SiO_(2) consumption,and better self-healing ability,significantly boosting the oxidation protection of the coating.
基金supported by the Russian Science Foundation(No.24-29-00682,https://rscf.ru/project/24-29-00682/).
文摘The majority of industrial aluminum casting alloys exhibit low thermal conductivity,which is insufficient for effective heat transfer in electronic devices.The objective of this investigation was to develop new aluminum casting alloys with high thermal conductivity.The impact of alloying elements on the thermal conductivity of pure aluminum was examined,and the relationships among microstructure,thermal conductivity,and the mechanical and corrosion properties of Al-Zn-Ca-(Cu,Mg)alloys were explored.The findings indicate that in the as-cast state,the structure of the alloys consists ofα-Al and a eutectic containing the(Al,Zn)4Ca phase.Following the solution heat treatment,the(Al,Zn)4Ca phase is spheroidised,and thermal conductivity of the alloys increases,reaching over 75%that of pure aluminum.However,the heat-treated alloys exhibit low mechanical properties:tensile yield strength<60 MPa,ultimate tensile strength<160 MPa,and elongation at fracture>15%.The alloys demonstrate satisfactory fluidity and low hot tearing susceptibility.With the exception of the alloy containing copper,the alloys exhibit low corrosion rates,estimated at approximately 0.02 mm/a.
基金funding from the Strategic project‘Technologies of Sustainable Development’of Program of strategic academic leadership‘Priority 2030’of NUST MISIS.
文摘The paper contains the results of investigation of interconnections between coals’vitrinite structural features,mode of its crushing under the cyclic nanoindentation with increasing peak load and coals’proneness to formation of airborne respirable dust(ARD)with particles sized<10μm(PM10).A specific value of PM10 contents in coals normalized on a fines fraction(with particles sizes of less than 200μm)was used as a measure of proneness to ARD formation.It has been shown that the aforementioned parameter is predefined by the ratio of amorphous and crystalline carbon compounds in vitrinite and the mode of its crushing.Some preliminary investigation have been done in order to characterize the involvement of inertinite in ARD formation.It was proposed that the inertinite is not as actively involved in the processes of ARD formation of coals as vitrinite,having a more diverse structural features in terms of amorphous to crystalline carbon compounds ratio.
文摘A parametrization of density matrices of ddimensions in terms of the raising J+and lowering J−angular momentum operators is established together with an implicit connection with the generalized Bloch-GellMann parameters. A general expression for the density matrix of the composite system of angular momenta j1and j2is obtained. In this matrix representation violations of the Bell-Clauser-Horne-Shimony-Holt inequalities are established for the X-states of a qubit-qubit, pure and mixed, composite system, as well as for a qubit-qutrit density matrix. In both cases maximal violation of the Bell inequalities can be reached, i.e., the Cirel’son limit. A correlation between the entanglement measure and a strong violation of the Bell factor is also given. For the qubit-qutrit composite system a time-dependent convex combination of the density matrix of the eigenstates of a two-particle Hamiltonian system is used to determine periodic maximal violations of the Bell’s inequality.
基金funded by the Russian Science Foundation(RSF),grantNo.24-23-00558,https://rscf.ru/en/project/24-23-00558/(accessed on 04 February 2025).
文摘The development of actuators based on ionic polymers as soft robotics,artificial muscles,and sensors is currently considered one of the most urgent topics.They are lightweight materials,in addition to their high efficiency,and they can be controlled by a low power source.Nevertheless,the most popular ionic polymers are derived from fossil-based resources.Hence,it is now deemed crucial to produce these actuators using sustainable materials.In this review,the use of ionic polymeric materials as actuators is reviewed through the emphasis on their role in the domain of renewablematerials.The reviewencompasses recent advancements inmaterial formulation and performance enhancement,alongside a comparative analysis with conventional actuator systems.It was found that renewable polymeric actuators based on ionic gels and conductive polymers are easier to prepare compared to ionic polymermetal composites.In addition,the proportion of actuator manufacturing utilizing renewable materials rose to 90%,particularly for ion gel actuators,which was related to the possibility of using renewable polymers as ionic or conductive substances.Moreover,the possible improvements in biopolymeric actuators will experience an annual rise of at least 10%over the next decade,correlating with the growth of their market,which aligns with the worldwide goal of reducing global warming.Additionally,compared to fossil-derived polymers,the decomposition rate of renewable materials reaches 100%,while biodegradable fossil-based substances can exceed 60%within several weeks.Ultimately,this review aims to elucidate the potential of ionic polymeric materials as a viable and sustainable solution for future actuator technologies.
基金Funding support of this work was carried out within the governmental task#075-00319-25-00.
文摘A study of the effect of rotary swaging(RS)at 350℃ on mechanical properties,corrosion resistance and biocompatibility in vitro and in vivo of biodegradable Mg-1%Zn-0.6%Ca alloy was conducted.It is shown that the formation of a recrystallized microstructure after RS with a grain size of 3.2±0.2μm leads to an increase in the strength of the alloy without reduction of level of ductility and corrosion resistance.At the same time,aging of the quenched alloy at 100℃ for 8 h leads to a slight increase in strength,but significantly reduces its ductility and corrosion resistance.The study of the degradation process of the alloy in the quenched state and after RS,both under in vitro and in vivo conditions,did not reveal a significant difference between these two microstructural states.However,an increase in the duration of incubation of the alloy in a complete growth medium from 4 h to 24 days leads to a decrease in the degradation rate(DR)by 4times(from~2 to~0.5 mm/year)due to the formation of a dense layer of degradation products.The study of biocompatibility in vitro did not reveal a significant effect of RS on the hemolytic and cytotoxic activity of the alloy.No signs of systemic toxicity were observed after subcutaneous implantation of alloy samples into mice before and after RS.However,it was found that RS promotes uniform degradation of the alloy over the entire contact surface.In summary,RS at 350℃ allows to increase the strength of Mg-1%Zn-0.6%Ca alloy up to348±5 MPa at a ductility level of 17.3±2.8%and a DRin vivoequal to 0.56±0.12 mm/year without impairing its biocompatibility in vitro and in vivo.
基金financial support from the Ministry of Education and Science of the Russian Federation, Agreement No. 03.G25.31.0274 (27 May 2017)
文摘Zn is a commonly used alloying element for Mg alloys owing to its beneficial effects on mechanical properties. To improve the mechanical and corrosion properties of WE43B Mg alloys, the effects of 0–0.7wt% Zn addition on the microstructure and properties of sample alloys were investigated. Addition of Zn to as-cast WE43B alloy promoted the formation of the Mg12Nd phase;by contrast, after T6 heat treatment, the phase composition of WE43B alloys with and without Zn addition remained mostly the same. A long-period stacking ordered phase was predicted by CALPHAD calculation, but this phase was not observed in either the as-cast or heat-treated Zn-containing WE43B alloys. The optimum temperature and duration of T6 heat treatment were obtained using CALPHAD calculations and hardness measurements. Addition of Zn resulted in a slight reduction in the average grain size of the as-cast and T6 heat-treated WE43B alloys and endowed them with increased corrosion resistance with little effect on their mechanical properties.
基金The authors gratefully acknowledge the financial support from the Ministry of Science and Higher Education of the Russian Federation in the framework of Increase Competitiveness Program of NUST 《MISiS》(№ К2-2019-008)implemented by a governmental decree dated 16th of March 2013,N 211.
文摘Biodegradable Mg-based implants are widely used in clinical applications because they exhibit mechanical properties comparable to those of human bone and require no revision surgery for their removal.Among Mg-based alloys,Mg–Zn–Ca–(Mn)alloys have been extensively investigated for medical applications because the constituent elements of these alloys,Mg,Zn,Ca,and Mn,are present in human tissues as nutrient elements.In this study,we investigated the effect of the hot extrusion temperature on the microstructure,mechanical properties,and biodegradation rate of Mg–Zn–Ca–(Mn)alloys.The results showed that the addition of Mn and a decrease in the extrusion temperature resulted in grain refinement followed by an increase in the strength and a decrease in the elongation at fracture of the alloys.The alloys showed different mechanical properties along the directions parallel and perpendicular to the extrusion direction.The corrosion test of the alloys in the Hanks’solution revealed that the addition of Mn significantly reduced the corrosion rate of the alloys.The Mg–2 wt%Zn–0.7 wt%Ca–1 wt%Mn alloy hot-extruded at 300℃ with an ultimate tensile strength of 278MPa,an yield strength of 229MPa,an elongation at fracture of 10%,and a corrosion rate of 0.3 mm/year was found to be suitable for orthopedic implants.
基金supported financially by the Russian Science Foundation(No.17-79-10256)。
文摘The microstructure and mechanical properties of novel Al-Y-Sc alloys with high thermal stability and electrical conductivity were investigated.Eutectic Al3 Y-phase particles of size 100-200 nm were detected in the as-cast microstructure of the alloys.Al3 Y-phase particles provided a higher hardness to as cast alloys than homogenized alloys in the temperature range of 370-440℃.L12 precipitates of the Al3(ScxYy) phase were nucleated homogenously within the aluminium matrix and heterogeneously on the dislocations during annealing at 400℃.The average size of the L12 precipitates was 11±2 nm after annealing for 1 h,and 25-30 nm after annealing for 5 h,which led to a decrease in the hardness of the Al-0.2 Y-0.2 Sc alloy to15 HV.The recrystallization temperature exceeded 350℃and 450℃for the Al-0.2 Y-0.05 Sc and Al-0.2 Y-0.2 Sc alloys,respectively.The investigated alloys demonstrated good thermal stability of the hardness and tensile properties after annealing the rolled alloys at 200 and 300℃,due to fixing of the dislocations and grain boundaries by L12 precipitates and eutectic Al3 Y-phase particles.The good combination of strength,plasticity,and electrical conductivity of the investigated Al-0.2 Y-0.2 Sc alloys make it a promising candidate for electrical conductors.The alloys exhibited a yield stress of 177-183 MPa,ultimate tensile stress of 199-202 MPa,elongation of 15.2-15.8%,and electrical conductivity of 60.8%-61.5% IACS.
基金kindly supported by the Russian Foundation for Basic Research (RFBR) (No. 16-05-00033A)
文摘Traditional methods of coal thermal resistance characterization are informative but considerably timeconsuming and require utilization of a complex and expensive equipment. This limits the effectiveness of their application. In this paper, authors experimentally investigated potential application of thermally stimulated acoustic emission method for developing of relatively simple and rapid coals thermal resistance assessment method. Features of thermally stimulated acoustic emission of anthracite, lignites and bituminous coal samples subject to cyclic thermal loading have been experimentally investigated.For the first time, it has been shown that there exists a relationship of such patterns with structural parameters and properties of the coal samples, as well as their thermal resistance. The results indicate the possibility of applying the method of thermally stimulated acoustic emission to control processes of cryogenic disintegration and thermal resistance of fossil coals. The description of the equipment and methodological support needed for the implementation of this method have been provided.
基金financial support of the Ministry of Science and Higher Education of the Russian Federation in the framework of Increase Competitiveness Program of NUST “MISi S” (No. К2-2019-007)
文摘Tribological behaviors of monolithic A356 aluminum alloy castings and A356.CNT nanocomposite castings, fabricated by fully liquid and semisolid routes were examined. Samples were prepared by melt agitation, rheocasting, stir casting, and compocasting techniques. Effects of addition of carbon nanotubes (CNTs), casting process and the applied load on wear properties and mechanisms were investigated. It was found that wear loss, wear rate and friction coefficient of nanocomposite samples remarkably declined by the addition of CNTs. Moreover, changing the casting process from fully liquid to semisolid routes, plus increasing fractions of the primary phase were the two factors that improved the wear properties of the investigated samples, especially nanocomposite ones. In addition, it was revealed that adhesion and delamination were the dominant wear mechanism of the monolithic samples produced by fully liquid and semisolid routes, respectively. However, regardless of fabrication techniques, the abrasion was the main wear mechanism of nanocomposite samples.
文摘Magnesium alloys are used in aircraft because of their light weight.However,for these alloys to be applied in electronic devices,high thermal conductivities are required.Several high-potential compositions of Mg-Zn-Y-Zr alloys were selected by phase composition and their freezing ranges calculated using Thermo-Calc software.The alloys were prepared,and their fluidity,hot tearing susceptibility,mechanical properties,and thermal conductivity were obtained and compared.The alloy composed of Mg-4 wt%Zn-3 wt%Y-0.3 wt%Zr was selected for further investigation,because of its high thermal conductivity and satisfactory mechanical properties.The Mg-4 wt%Zn-3 wt%Y-0.3 wt%Zr alloy’s fluidity and hot tearing susceptibility were similar to those of the widespread AZ91 commercial casting magnesium alloy.The influence of a heat treatment regime on the microstructure,thermal conductivity,and mechanical properties of the developed alloy was also investigated.It was established that the room temperature thermal conductivity of the Mg-4 wt%Zn-3 wt%Y-0.3 wt%Zr alloy after aging at 300℃for 5 h was 105 W/m K^(-1).Additionally,the following tensile test results were obtained in aged condition:120 MPa yield strength,200 MPa ultimate tensile strength,and 4%elongation.The utilization of solid solution heat treatment at 520℃for 8 h prior to aging can promote up to 9%increase in elongation.The Mg-4 wt%Zn-3 wt%Y-0.3 wt%Zr casting alloy can be used as a high thermal conductivity material with industrial applications.
基金financially supported by the Ministry of Education and Science of the Russian Federation in the framework of increase Competitiveness Program of NUST ‘‘MISIS’’, implemented by a governmental decree dated 16th of March 2013, No. 211part of state assignment Organization of scientific researches (Project No. 16.6548.2017/BY)
文摘Lateral flow immunoassay(LFIA) is a widely used express method and offers advantages such as a short analysis time, simplicity of testing and result evaluation.However, an LFIA based on gold nanospheres lacks the desired sensitivity, thereby limiting its wide applications.In this study, spherical nanogold labels along with new types of nanogold labels such as gold nanopopcorns and nanostars were prepared, characterized, and applied for LFIA of model protein antigen procalcitonin. It was found that the label with a structure close to spherical provided more uniform distribution of specific antibodies on its surface, indicative of its suitability for this type of analysis.LFIA using gold nanopopcorns as a label allowed procalcitonin detection over a linear range of 0.5–10 ng mL^(-1) with the limit of detection of 0.1 ng mL^(-1), which was fivefold higher than the sensitivity of the assay with gold nanospheres. Another approach to improve the sensitivity of the assay included the silver enhancement method,which was used to compare the amplification of LFIA for procalcitonin detection. The sensitivity of procalcitonin determination by this method was 10 times better the sensitivity of the conventional LFIA with gold nanosphere as a label. The proposed approach of LFIA based on gold nanopopcorns improved the detection sensitivity without additional steps and prevented the increased consumption of specific reagents(antibodies).
文摘Application of calcium as alloying element for magnesium alloys has been considered according to literature data.Mg–7%Al–4%Ca–0.5%Mn casting alloy was offered,which possesses the low propensity to the hot brittleness and good castability.The alloy has the moderate strength(σu=150 MPa)and the satisfactory percentage elongation(δ=3%).It is shown,that calcium-containing alloys smelting of Mg–Al–Ca–Mn system is preferable with the application of low-chloride flux FL10(20%MgCl_(2);29%KCl;12%BaCl_(2);23%CaF2;15%MgF2;1%B2O3).The alloy smelting in the atmosphere of argon and SF6 mixture results in the increased shelling and waste of calcium.The heat treatment is offered for the developed alloy,which is directed to the Al_(2)Ca phase spheroidizing.The developed magnesium alloy,alloyed with calcium,is perspective for the industry production of low-cost moulding.
