High cyclic fatigue(HCF)behavior of an AA2139alloy belonging to Al-Cu-Mg-Ag system in T6and T840conditionswas examined.The T840treatment involving cold rolling with a40%reduction prior to peak ageing provides an incre...High cyclic fatigue(HCF)behavior of an AA2139alloy belonging to Al-Cu-Mg-Ag system in T6and T840conditionswas examined.The T840treatment involving cold rolling with a40%reduction prior to peak ageing provides an increase in tensilestrength compared with the T6condition.However,fatigue lifetime for two material conditions was nearly the same since there isweak effect of thermomechanical processing on micro-mechanisms of crack initiation and growth.展开更多
Three-pass friction stir processing(FSP)with different moving distances of the stirring tool between the two successivepasses,50%diameter of the pin(traditional way)and50%diameter of the shoulder(novel way),was conduc...Three-pass friction stir processing(FSP)with different moving distances of the stirring tool between the two successivepasses,50%diameter of the pin(traditional way)and50%diameter of the shoulder(novel way),was conducted on7B04-O Al alloy.The result shows that an improvement in the mechanical properties of the processed zone is accomplished due to grain and secondphase particles refinement.The hardness of the multi-pass FSP(M-FSP)sample is about HV40higher than that of the base metal.And the tensile strength of the M-FSP specimens is also significantly increased to about1.4times that of the base metal.Besides,theweak region of the processed zone is mainly dependent on the moving distance,where it is the previous pass stir zone in thetraditional way and the transitional zone in the novel way.Increasing the rotational speed narrows the weak region in the novel way,while it does not in the traditional way.展开更多
The n-type thermoelectric Bi_(1.9)Lu_(0.1)Te_3 was prepared by microwave-solvothermal method and spark plasma sintering. The magnetic field and temperature dependences of transverse magneto resistance measured within ...The n-type thermoelectric Bi_(1.9)Lu_(0.1)Te_3 was prepared by microwave-solvothermal method and spark plasma sintering. The magnetic field and temperature dependences of transverse magneto resistance measured within temperature 2-200 K interval allow finding the peculiarities characteristic for strongly disordered and inhomogeneous semiconductors. The first peculiarity is due to appearance of linear-inmagnetic field contribution to the total magneto resistance reflected in a crossover from quadratic magnetoresistance at low magnetic fields to linear magneto resistance at high magnetic fields. The linear magnetoresistance can result from the Hall resistance picked up from macroscopically distorted current paths due to local variations in stoichiometry of the compound studied. The second peculiarity is that both linear magnetoresistance magnitude and crossover field are functions of carrier mobility which is in agreement with the Parish and Littlewood model developed for disordered and inhomogeneous semiconductors. An increase in the mobility due to a decrease in temperature is accompanied by an increase in the magnetoresistance magnitude and a decrease in the crossover field. Finally, the third peculiarity is related to the remarkable deviation of the total magnetoresistance measured at various temperatures from the Kohler's rule. Presence of strong inhomogeneity and disorder in the Bi_(1.9)Lu_(0.1)Te_3 structure concluded from the magnetoresistance peculiarities can be responsible for the remarkable reduction in the total thermal conductivity of this compound.展开更多
In this paper we describe a route to produce crystalline Mg（OH）2 nanopowders from serpentinite ore distributed in the Halilovskiy array （Russia, Orenburg region）. An efficient extraction route consisting of treatm...In this paper we describe a route to produce crystalline Mg（OH）2 nanopowders from serpentinite ore distributed in the Halilovskiy array （Russia, Orenburg region）. An efficient extraction route consisting of treatment on serpentinite in 40% HNO3 at 80 ℃followed by NH4OH titration for Mg（OH）2 precipitation was demonstrated. In this study, crystalline Mg（OH）2 nanopowders have been synthesized by solvothermal reaction method using （Mg（NO3）2·6H2O） which were obtained from serpentinite, NH4OH as a precipitator, and hydroxyethylated nonylphenol as surface-active substance. Microstructure and phase composition of samples were investigated employing scanning electron microscopy （SEM） and transmission electron microscopy （TEM）, X-ray phase analysis （XRD）, and inductively coupled plasma optical emission spectroscopy （ICP-OES）. XRD reveals that Mg（OH）2 nanopowder with high purity has the brucite structure. It was found that crystalline Mg（OH）2 nanopowders exclusively consist of lamellar-like structures and the sizes of Mg（OH）2 are 30-265 nm length or width.展开更多
Effect of fabrication conditions on microstructure and thermoelectric properties of the Bi1.9Lu0.lTe3 compound was studied. Starting nanopowder with mean nanoparticle size of -37 nm was synthesized by a microwave-solv...Effect of fabrication conditions on microstructure and thermoelectric properties of the Bi1.9Lu0.lTe3 compound was studied. Starting nanopowder with mean nanoparticle size of -37 nm was synthesized by a microwave-solvothermal method. In order to prepare samples with various micro-grained structures, the synthesized nanopowder was compacted by two methods. The first method is cold isostatic pressing with further high- temperature annealing, while the second method is spark plasma sintering at various temperatures of process （653 and 683 K）. It is found that mean grain size is equal to -290,-730 and -1160 nm for cold isostatically pressed and spark plasma sintered at 653 and 683 K samples, respectively. The micro-grained sample with maximum mean grain size shows the best thermoelectric properties. This sample is structurally inhomogeneous and has the lowest thermal conductivity and the specific electrical resistivity. Maximum dimensionless figure of merit for this sample is equal to -0.9 for temperature range of 450-500 K.展开更多
Chemical heterogeneity in high-temperature austenite is an effective way to tune the austenite-to-martensite transformation during cooling.The effect of quenching temperature on microstructure evolution is investigate...Chemical heterogeneity in high-temperature austenite is an effective way to tune the austenite-to-martensite transformation during cooling.The effect of quenching temperature on microstructure evolution is investigated when the high-temperature austenite is heterogeneous.After fast austenitization from partitioned pearlite consisting of Mn-enriched cementite and Mn-depleted ferrite in Fe-0.29C-3.76Mn-1.50Si(wt.%)steel,quenching to room temperature and quenching to 130℃followed by 400℃partitioning are both applied.With increasing quenching temperature from 25 to 130℃,the amount of heterogeneous microstructure(lamellar ghost pearlite)increases from 10.6%to 33.6%and the thickness of Mn-enriched retained austenite film is increased from 31.9±5.9 to 51.5±4.4 nm,indicating an enhancement of chemical patterning.It is probably ascribed to the reduction in driving force for austenite-to-martensite transformation,which requires a lower Mn content for austenite retention.展开更多
AIM：To examine the association of genetic polymorphisms（-308）G/A TNFα,（＋250）A/G Ltα,（＋36）A/G TNFR1,（＋1663）A/G TNFR2 with the development of primary open angle glaucoma（POAG）among people in Central Russ...AIM：To examine the association of genetic polymorphisms（-308）G/A TNFα,（＋250）A/G Ltα,（＋36）A/G TNFR1,（＋1663）A/G TNFR2 with the development of primary open angle glaucoma（POAG）among people in Central Russia.METHODS：The study sample included 443 individuals,of which 252 patients with POAG and 191 individuals in the control group.Genotyping of（-308）G/A TNFα,（＋250）A/G Ltα,（＋36）A/G TNFR1,（＋1663）A/G TNFR2 was performed using polymerase chain reaction.The distribution of alleles and genotypes of the studied DNA markers in the groups was examined by 2×2 contingency tables andχ2with the Yates’s correction for continuity and odds ratios（OR）with95%confidence intervals（CI）.RESULTS：Allele（-308）G TNFα（Р=0.01,OR=1.78,95%CI1.12-2.85）was identified as a risk factor for POAG.Homozygotes（-308）AA TNFαare at a lowest risk for development of the disease（Р=0.01,OR=0.0005）.The following combination of genetic variants of cytokines were associated with a reduced risk of POAG：（＋1663）A TNFR2 and（＋250）G Ltα（OR=0.34）CONCLUSION：Genetic polymorphisms（-308）G/A TNFα,（＋250）A/G Ltα,（＋1663）A/G TNFR2 associated with the development of POAG in the population of Central Russia.展开更多
A novel double side friction stir Z shape lap-butt welding(DS-FSZW)process was proposed to achieve excellent mechanical properties of Al/Cu medium-thick dissimilar joints.The influence of welding parameters on weld mi...A novel double side friction stir Z shape lap-butt welding(DS-FSZW)process was proposed to achieve excellent mechanical properties of Al/Cu medium-thick dissimilar joints.The influence of welding parameters on weld microstructure and properties of DS-FSZW joint were systematically investigated.It indicated that defect-free medium-thick Al/Cu DS-FSZW joint could be achieved under an optimal welding parameter.DS-FSZW joint was prone to form void defects in the bottom of the second-pass weld.The recrystallization mechanisms at the top and middle of the weld nugget zone(WNZ)were continuous dynamic recrystallization(CDRX)and geometric dynamic recrystallization(GDRX).While the major recrystallization mechanism at the bottom of the WNZ was GDRX.DS-FSZW joint of the optimal welding condition with 850 r/min-400 mm/min was produced with a continuous thin and crack-free IMCs layer at the Al/Cu interface,and the maximum tensile strength of this joint is 160.57 MPa,which is equivalent to 65.54%of pure Cu base material.Moreover,the corrosion resistance of Al/Cu DS-FSZW joints also achieved its maximum value at the optimal welding parameter of 850 r/min-400 mm/min.It demonstrates that the DS-FSZW process can simultaneously produce medium-thick Al/Cu joints with excellent mechanical performance and corrosion resistance.展开更多
A systematic study of two-phase(water-air)currents in open channels(water-air)has been conducted by means of experiments and numerical simulations.A dedicated device has been designed and manufactured on purpose.The n...A systematic study of two-phase(water-air)currents in open channels(water-air)has been conducted by means of experiments and numerical simulations.A dedicated device has been designed and manufactured on purpose.The numerical simulations have been based on the solution of a system of mass,momentum and energy balance equations for a two-phase fluid.The effect of different influential parameters has been explored,namely,velocity and dimensions of the channel,surface pressure and tension.展开更多
In this study,structural theory was used to examine the geometric configuration of channels embedded inside an object in the presence of internal heat generation for cooling by a heat transfer mechanism.The growth and...In this study,structural theory was used to examine the geometric configuration of channels embedded inside an object in the presence of internal heat generation for cooling by a heat transfer mechanism.The growth and development of gas transmission lines and the lack of up-to-date integrated information systems have made the design and maintenance of pipelines,as well as the handling of problems caused by various accidents in the pipeline,very complex in many cases.Using accurate descriptive and spatial information in tolls on gas transmission line maps such as pipes,booster stations,valves,and forks in a spatial reference database can engage planners,operators,and paramedics in a variety of management.They are used to help in the direction of optimal and purposeful management.Therefore,in this paper,by considering appropriate laboratory conditions and numerical experiments and calculations,it is possible to determine the optimal attraction of duct holes for cooling components of the gas transmission system,so that the industry can produce and developed gas transmission without incident.In this study,in addition to studying the geometric characteristics of channel spacing and their length,the dimensions of a specific channel for reducing the maximum produced temperature are also discussed.展开更多
The nanoparticles of SiO2 were used in cement systems to modify the rheological behavior, to enhance the reactivity of supplementary cementitious materials, and also to improve the strength and durability. In this res...The nanoparticles of SiO2 were used in cement systems to modify the rheological behavior, to enhance the reactivity of supplementary cementitious materials, and also to improve the strength and durability. In this research, low-cost nano-SiO2 particles from natural hydrothermal solutions obtained by membrane ultrafiltration and, optionally, by cryochemical vacuum sublimation drying, were evaluated in portland cement based systems. The SiO2-rich solutions were obtained from the wells of Mutnovsky geothermal power station （Far East of Russia）. The constant nano-SiO2 dosage of 0.25% （as a solid material by weight of cementitious materials） was used to compare the cement systems with different nanoparticles against a reference mortar and a commercially available nano-SiO2. Nanoparticles were characterized by X-Ray Diffraction （XRD）, BET Surface Area, Scanning Electron Microscope （SEM） and Fourier Transform Infrared （FTIR） spectroscopy techniques. It was demonstrated that the addition of polycarboxylate ether superplasticizer and the dispersion treatment using an ultrasound processor can be used to facilitate the distribution ofnano-SiOz particles in the mixing water. The effect ofnano-SiO2 particles in portland cement mortars was investigated by evaluating the flow, heat of hydration and compressive strength development. It was demonstrated that the use ofnano- SiO2 particles can reduce the segregation and improve strength properties.展开更多
Objective:Metabolic disturbances in the folate cycle in mothers can lead to fetal growth retardation(FGR).This study was to analyze the role of intergenic interactions among maternal folate cycle genes in the developm...Objective:Metabolic disturbances in the folate cycle in mothers can lead to fetal growth retardation(FGR).This study was to analyze the role of intergenic interactions among maternal folate cycle genes in the development of FGR.Methods:This case-control study recruited 365 women in the third trimester of pregnancy,including 122 FGR patients and 243 controls.The women were genotyped for 5 polymorphisms of the 4 folate cycle genes:MTR(rs1805087),MTRR(rs1801394),serine hydroxymethyl transferase(SHMT1;rs1979277),and TYMS(rs699517 and rs2790).The SNP×SNP interactions in the two-,three-,and four-locus models were analyzed using the multifactor dimensionality reduction method and a modification of it(the model-based multifactor dimensionality reduction method).Results:Four loci of maternal folate cycle genes(rs1805087 MTR,rs2790 TYMS,rs1801394 MTRR,and rs1979277 SHMT1)were associated with FGR in 3 significant models of single nucleotide polymorphism(SNP)×SNP interactions(two-,three-,and four-locus models)(P<0.05).The highest contribution to FGR was made by polymorphic loci rs1979277 SHMT1(1.70%of entropy),rs1805087 MTR(0.96%),and interactions between rs1979277 SHMT1×rs1805087 MTR(-1.11%)and rs1801394 MTRR×rs1979277 SHMT1(-0.64%).The four-locus maternal genotype combination AG rs1801394 MTRR×AA rs1805087 MTR×CT rs1979277 SHMT1×AG rs2790 TYMS was associated with an increased risk of FGR(β=2.69,P=0.012).FGR-associated SNPs were correlated with the expression of 16 genes(MTR,MTRR,SHMT1,ALKBH5,CTD-2303H24.2,ENOSF1,FAM106A,FOXO3B,LGALS9C,LLGL1,MIEF2,NOS2P2,RP11-806L2.6,SMCR8,TOP3A,and USP32P2)in various tissues and organs related to FGR pathophysiology.Conclusion:SNP×SNP interactions of maternal folate cycle genes(MTR,MTRR,SHMT1,and TYMS)are associated with the development of FGR.展开更多
Halide perovskites possess ultra-low thermal conductivity and show high potential for thermoelectric devices.The chemical properties and molecular structure of halide perovskite materials are not completely stable und...Halide perovskites possess ultra-low thermal conductivity and show high potential for thermoelectric devices.The chemical properties and molecular structure of halide perovskite materials are not completely stable under ambient conditions,which hinders their use in thermoelectric generators.Changes in the properties of bulk halide perovskite thermoelectrics are accompanied by partial phase transitions and surface oxidation processes.In this paper,we conducted a comprehensive study of the transport and structural properties of CsSnI_(3),which were pristine by vacuum melting followed by spark plasma sintering.The research results on the electrical transport of these materials revealed that exposure to an inert atmosphere does not deteriorate stability and the properties of the materials remain unchanged.However,prolonged exposure to air leads to a significant degradation of the electrical transport properties.Contrary to thin-film samples,the shift to the double perovskite structure from the perovskite one is limited to a specific surface layer.This change significantly influences the electrical transport of the material while maintaining the essential properties of both perovskite types.展开更多
This paper presents the results of studying the surface properties changes of a ther-moregulating coating based on polystyrene and silicafiller after proton irradiation with an en-ergy of 50 keV at afluence of 3�1015 ...This paper presents the results of studying the surface properties changes of a ther-moregulating coating based on polystyrene and silicafiller after proton irradiation with an en-ergy of 50 keV at afluence of 3�1015 cm�2.After proton irradiation,the values of the contact angle of wetting with water increase by 3.5%and 14.9%for polystyrene and the coating,respectively.The free surface energy(energy of the surface layer)of polystyrene and the coat-ings before and after proton irradiation was calculated using the Owens-Wendt-Rabel-Kaelble method.There was a significant increase in the polarity of the polystyrene surface(gp increased by a factor of 2.2)after proton irradiation.For the coating,an increase in gp by a factor of 3.89 was observed after proton irradiation.Structural changes in the coating were presented by IR Fourier spectroscopy.A slight decrease in the absorption intensity of all characteristic bands compared to the unirradiated sample was noted.It was found that the irradiation of the coating with protons led to the formation of macromolecules with hydroxyl,carbonyl,and carboxyl bonds,as well as the formation of dimeric and oligomeric siloxane chains.It was also found that after irradiation of a pure polystyrene sample with protons,the value of the solar absorption as increased by only 4.2%;whereas for the coating with silicafiller,the value of as increased by 28.6%.展开更多
We formulated and analyzed a novel nanoformulation of the anticancer drug cisplatin （Cis） with C60 fullerene （C60＋Cis complex） and showed its higher toxicity toward tumor cell lines in vitro when compared to Cis ...We formulated and analyzed a novel nanoformulation of the anticancer drug cisplatin （Cis） with C60 fullerene （C60＋Cis complex） and showed its higher toxicity toward tumor cell lines in vitro when compared to Cis alone. The highest toxicity of the complex was observed in HL-60/adr and HL-60/vinc chemotherapy- resistant human leukemia cell sublines （resistant to Adriamycin and Vinculin, respectively）. We discovered that the action of the C60＋Cis complex is associated with overcoming the drug resistance of the tumor cell lines through observing an increased number of apoptotic cells in the Annexin V/PI assay. Moreover, in vivo assays with Lewis lung carcinoma （LLC） C57BL/6J male mice showed that the C60＋Cis complex increases tumor growth inhibition, when compared to Cis or C60 fullerenes alone. Simultaneously, we conducted a molecular docking study and performed an Ames test. Molecular docking specifies the capability of a C60 fullerene to form van der Waals interactions with potential binding sites on P-glycoprotein （P-gp）, multidrug resistance protein 1 （MRP-1）, and multidrug resistance protein 2 （MRP-2） molecules. The observed phenomenon revealed a possible mechanism to bypass tumor cell drug resistance by the C60＋Cis complex. Additionally, the results of the Ames test show that the formation of such a complex diminishes the Cis mutagenic activity and may reduce the probability of secondary neoplasm formation. In conclusion, the C60＋Cis complex effectively induced tumor cell death in vitro and inhibited tumor growth in vivo, overcoming drug resistance likely by the potential of the C60 fullerene to interact with P-gp, MRP-1, and MRP-2 molecules. Thus, the C60＋Cis complex might be a potential novel chemotherapy modification.展开更多
基金a joint project between USATU (Ufa State Aviation Technical University) and UMPO (Ufa Engine Industrial Association), which is entitled “Elaboration and industrial development of high-precision shaping coordinated technologies and superficial hardening of responsible details from Al-alloys with heightened constructional energy efficiency”. This project was implemented under contract No. 40/10-30976/NCh-NCh01-13-KhGthe Ministry of Education and Science of the Russian Federation (contract No.02.G25.31.0010 between UMPO and the Ministry of Education and Science of the Russian Federation) via the Resolution of the Russian Federation Government No.218 from April 9,2010
文摘High cyclic fatigue(HCF)behavior of an AA2139alloy belonging to Al-Cu-Mg-Ag system in T6and T840conditionswas examined.The T840treatment involving cold rolling with a40%reduction prior to peak ageing provides an increase in tensilestrength compared with the T6condition.However,fatigue lifetime for two material conditions was nearly the same since there isweak effect of thermomechanical processing on micro-mechanisms of crack initiation and growth.
基金support received from the Ministry of Education and Science,Russia,(Belgorod State University project No.1533)is acknowledgedsupport from the National Science Foundation for Young Scientists of China(No.51501035)+1 种基金Chinese Postdoctoral Science Foundation(No.2016T90227)supported financially by the National Natural Science Foundation of China(No.51334006)
文摘Three-pass friction stir processing(FSP)with different moving distances of the stirring tool between the two successivepasses,50%diameter of the pin(traditional way)and50%diameter of the shoulder(novel way),was conducted on7B04-O Al alloy.The result shows that an improvement in the mechanical properties of the processed zone is accomplished due to grain and secondphase particles refinement.The hardness of the multi-pass FSP(M-FSP)sample is about HV40higher than that of the base metal.And the tensile strength of the M-FSP specimens is also significantly increased to about1.4times that of the base metal.Besides,theweak region of the processed zone is mainly dependent on the moving distance,where it is the previous pass stir zone in thetraditional way and the transitional zone in the novel way.Increasing the rotational speed narrows the weak region in the novel way,while it does not in the traditional way.
基金Project supported by the Ministry of Education and Science of the Russian Federation(3.6586.2017/6.7)
文摘The n-type thermoelectric Bi_(1.9)Lu_(0.1)Te_3 was prepared by microwave-solvothermal method and spark plasma sintering. The magnetic field and temperature dependences of transverse magneto resistance measured within temperature 2-200 K interval allow finding the peculiarities characteristic for strongly disordered and inhomogeneous semiconductors. The first peculiarity is due to appearance of linear-inmagnetic field contribution to the total magneto resistance reflected in a crossover from quadratic magnetoresistance at low magnetic fields to linear magneto resistance at high magnetic fields. The linear magnetoresistance can result from the Hall resistance picked up from macroscopically distorted current paths due to local variations in stoichiometry of the compound studied. The second peculiarity is that both linear magnetoresistance magnitude and crossover field are functions of carrier mobility which is in agreement with the Parish and Littlewood model developed for disordered and inhomogeneous semiconductors. An increase in the mobility due to a decrease in temperature is accompanied by an increase in the magnetoresistance magnitude and a decrease in the crossover field. Finally, the third peculiarity is related to the remarkable deviation of the total magnetoresistance measured at various temperatures from the Kohler's rule. Presence of strong inhomogeneity and disorder in the Bi_(1.9)Lu_(0.1)Te_3 structure concluded from the magnetoresistance peculiarities can be responsible for the remarkable reduction in the total thermal conductivity of this compound.
基金the state on behalf of the Ministry of Education and Science of the Russian Federation of the Agreement (No. 14.577.21.0111 (22 September 2014))The unique identifier of the applied research (No. RFMEFI57714X0111)
文摘In this paper we describe a route to produce crystalline Mg（OH）2 nanopowders from serpentinite ore distributed in the Halilovskiy array （Russia, Orenburg region）. An efficient extraction route consisting of treatment on serpentinite in 40% HNO3 at 80 ℃followed by NH4OH titration for Mg（OH）2 precipitation was demonstrated. In this study, crystalline Mg（OH）2 nanopowders have been synthesized by solvothermal reaction method using （Mg（NO3）2·6H2O） which were obtained from serpentinite, NH4OH as a precipitator, and hydroxyethylated nonylphenol as surface-active substance. Microstructure and phase composition of samples were investigated employing scanning electron microscopy （SEM） and transmission electron microscopy （TEM）, X-ray phase analysis （XRD）, and inductively coupled plasma optical emission spectroscopy （ICP-OES）. XRD reveals that Mg（OH）2 nanopowder with high purity has the brucite structure. It was found that crystalline Mg（OH）2 nanopowders exclusively consist of lamellar-like structures and the sizes of Mg（OH）2 are 30-265 nm length or width.
基金financially supported by the Ministry of Education and Science of the Russian Federation (No.3.6586.2017/BY and 03.G25.31.0246)
文摘Effect of fabrication conditions on microstructure and thermoelectric properties of the Bi1.9Lu0.lTe3 compound was studied. Starting nanopowder with mean nanoparticle size of -37 nm was synthesized by a microwave-solvothermal method. In order to prepare samples with various micro-grained structures, the synthesized nanopowder was compacted by two methods. The first method is cold isostatic pressing with further high- temperature annealing, while the second method is spark plasma sintering at various temperatures of process （653 and 683 K）. It is found that mean grain size is equal to -290,-730 and -1160 nm for cold isostatically pressed and spark plasma sintered at 653 and 683 K samples, respectively. The micro-grained sample with maximum mean grain size shows the best thermoelectric properties. This sample is structurally inhomogeneous and has the lowest thermal conductivity and the specific electrical resistivity. Maximum dimensionless figure of merit for this sample is equal to -0.9 for temperature range of 450-500 K.
基金the financial support from the National Natural Science Foundation of China(52271004 and 51901021)the"Beijing Institute of Technology Research Fund Program for Young Scholars".
文摘Chemical heterogeneity in high-temperature austenite is an effective way to tune the austenite-to-martensite transformation during cooling.The effect of quenching temperature on microstructure evolution is investigated when the high-temperature austenite is heterogeneous.After fast austenitization from partitioned pearlite consisting of Mn-enriched cementite and Mn-depleted ferrite in Fe-0.29C-3.76Mn-1.50Si(wt.%)steel,quenching to room temperature and quenching to 130℃followed by 400℃partitioning are both applied.With increasing quenching temperature from 25 to 130℃,the amount of heterogeneous microstructure(lamellar ghost pearlite)increases from 10.6%to 33.6%and the thickness of Mn-enriched retained austenite film is increased from 31.9±5.9 to 51.5±4.4 nm,indicating an enhancement of chemical patterning.It is probably ascribed to the reduction in driving force for austenite-to-martensite transformation,which requires a lower Mn content for austenite retention.
文摘AIM：To examine the association of genetic polymorphisms（-308）G/A TNFα,（＋250）A/G Ltα,（＋36）A/G TNFR1,（＋1663）A/G TNFR2 with the development of primary open angle glaucoma（POAG）among people in Central Russia.METHODS：The study sample included 443 individuals,of which 252 patients with POAG and 191 individuals in the control group.Genotyping of（-308）G/A TNFα,（＋250）A/G Ltα,（＋36）A/G TNFR1,（＋1663）A/G TNFR2 was performed using polymerase chain reaction.The distribution of alleles and genotypes of the studied DNA markers in the groups was examined by 2×2 contingency tables andχ2with the Yates’s correction for continuity and odds ratios（OR）with95%confidence intervals（CI）.RESULTS：Allele（-308）G TNFα（Р=0.01,OR=1.78,95%CI1.12-2.85）was identified as a risk factor for POAG.Homozygotes（-308）AA TNFαare at a lowest risk for development of the disease（Р=0.01,OR=0.0005）.The following combination of genetic variants of cytokines were associated with a reduced risk of POAG：（＋1663）A TNFR2 and（＋250）G Ltα（OR=0.34）CONCLUSION：Genetic polymorphisms（-308）G/A TNFα,（＋250）A/G Ltα,（＋1663）A/G TNFR2 associated with the development of POAG in the population of Central Russia.
基金Supported by National Natural Science Foundation of China(Grant Nos.52275349,52035005)Key Research and Development Program of Shandong Province of China(Grant No.2021ZLGX01)Qilu Young Scholar Program of Shandong University of China.
文摘A novel double side friction stir Z shape lap-butt welding(DS-FSZW)process was proposed to achieve excellent mechanical properties of Al/Cu medium-thick dissimilar joints.The influence of welding parameters on weld microstructure and properties of DS-FSZW joint were systematically investigated.It indicated that defect-free medium-thick Al/Cu DS-FSZW joint could be achieved under an optimal welding parameter.DS-FSZW joint was prone to form void defects in the bottom of the second-pass weld.The recrystallization mechanisms at the top and middle of the weld nugget zone(WNZ)were continuous dynamic recrystallization(CDRX)and geometric dynamic recrystallization(GDRX).While the major recrystallization mechanism at the bottom of the WNZ was GDRX.DS-FSZW joint of the optimal welding condition with 850 r/min-400 mm/min was produced with a continuous thin and crack-free IMCs layer at the Al/Cu interface,and the maximum tensile strength of this joint is 160.57 MPa,which is equivalent to 65.54%of pure Cu base material.Moreover,the corrosion resistance of Al/Cu DS-FSZW joints also achieved its maximum value at the optimal welding parameter of 850 r/min-400 mm/min.It demonstrates that the DS-FSZW process can simultaneously produce medium-thick Al/Cu joints with excellent mechanical performance and corrosion resistance.
基金The article was prepared as part of the state task“Research and development of complex energy-saving and thermoelectric regenerative systems”Application No.2019–1497,Subject No.FZWG-2020-0034。
文摘A systematic study of two-phase(water-air)currents in open channels(water-air)has been conducted by means of experiments and numerical simulations.A dedicated device has been designed and manufactured on purpose.The numerical simulations have been based on the solution of a system of mass,momentum and energy balance equations for a two-phase fluid.The effect of different influential parameters has been explored,namely,velocity and dimensions of the channel,surface pressure and tension.
基金The article was prepared as part of the state task“Research and development of complex energy-saving and thermoelectric regenerative systems”Application No.2019–1497,Subject No.FZWG-2020-0034.
文摘In this study,structural theory was used to examine the geometric configuration of channels embedded inside an object in the presence of internal heat generation for cooling by a heat transfer mechanism.The growth and development of gas transmission lines and the lack of up-to-date integrated information systems have made the design and maintenance of pipelines,as well as the handling of problems caused by various accidents in the pipeline,very complex in many cases.Using accurate descriptive and spatial information in tolls on gas transmission line maps such as pipes,booster stations,valves,and forks in a spatial reference database can engage planners,operators,and paramedics in a variety of management.They are used to help in the direction of optimal and purposeful management.Therefore,in this paper,by considering appropriate laboratory conditions and numerical experiments and calculations,it is possible to determine the optimal attraction of duct holes for cooling components of the gas transmission system,so that the industry can produce and developed gas transmission without incident.In this study,in addition to studying the geometric characteristics of channel spacing and their length,the dimensions of a specific channel for reducing the maximum produced temperature are also discussed.
文摘The nanoparticles of SiO2 were used in cement systems to modify the rheological behavior, to enhance the reactivity of supplementary cementitious materials, and also to improve the strength and durability. In this research, low-cost nano-SiO2 particles from natural hydrothermal solutions obtained by membrane ultrafiltration and, optionally, by cryochemical vacuum sublimation drying, were evaluated in portland cement based systems. The SiO2-rich solutions were obtained from the wells of Mutnovsky geothermal power station （Far East of Russia）. The constant nano-SiO2 dosage of 0.25% （as a solid material by weight of cementitious materials） was used to compare the cement systems with different nanoparticles against a reference mortar and a commercially available nano-SiO2. Nanoparticles were characterized by X-Ray Diffraction （XRD）, BET Surface Area, Scanning Electron Microscope （SEM） and Fourier Transform Infrared （FTIR） spectroscopy techniques. It was demonstrated that the addition of polycarboxylate ether superplasticizer and the dispersion treatment using an ultrasound processor can be used to facilitate the distribution ofnano-SiOz particles in the mixing water. The effect ofnano-SiO2 particles in portland cement mortars was investigated by evaluating the flow, heat of hydration and compressive strength development. It was demonstrated that the use ofnano- SiO2 particles can reduce the segregation and improve strength properties.
基金President of the Russian Federation"Study of genetic factors of women's reproductive health"(MD-3284.2022.1.4)
文摘Objective:Metabolic disturbances in the folate cycle in mothers can lead to fetal growth retardation(FGR).This study was to analyze the role of intergenic interactions among maternal folate cycle genes in the development of FGR.Methods:This case-control study recruited 365 women in the third trimester of pregnancy,including 122 FGR patients and 243 controls.The women were genotyped for 5 polymorphisms of the 4 folate cycle genes:MTR(rs1805087),MTRR(rs1801394),serine hydroxymethyl transferase(SHMT1;rs1979277),and TYMS(rs699517 and rs2790).The SNP×SNP interactions in the two-,three-,and four-locus models were analyzed using the multifactor dimensionality reduction method and a modification of it(the model-based multifactor dimensionality reduction method).Results:Four loci of maternal folate cycle genes(rs1805087 MTR,rs2790 TYMS,rs1801394 MTRR,and rs1979277 SHMT1)were associated with FGR in 3 significant models of single nucleotide polymorphism(SNP)×SNP interactions(two-,three-,and four-locus models)(P<0.05).The highest contribution to FGR was made by polymorphic loci rs1979277 SHMT1(1.70%of entropy),rs1805087 MTR(0.96%),and interactions between rs1979277 SHMT1×rs1805087 MTR(-1.11%)and rs1801394 MTRR×rs1979277 SHMT1(-0.64%).The four-locus maternal genotype combination AG rs1801394 MTRR×AA rs1805087 MTR×CT rs1979277 SHMT1×AG rs2790 TYMS was associated with an increased risk of FGR(β=2.69,P=0.012).FGR-associated SNPs were correlated with the expression of 16 genes(MTR,MTRR,SHMT1,ALKBH5,CTD-2303H24.2,ENOSF1,FAM106A,FOXO3B,LGALS9C,LLGL1,MIEF2,NOS2P2,RP11-806L2.6,SMCR8,TOP3A,and USP32P2)in various tissues and organs related to FGR pathophysiology.Conclusion:SNP×SNP interactions of maternal folate cycle genes(MTR,MTRR,SHMT1,and TYMS)are associated with the development of FGR.
基金support from the Russian Science Foundation(project no.22-79-10326).
文摘Halide perovskites possess ultra-low thermal conductivity and show high potential for thermoelectric devices.The chemical properties and molecular structure of halide perovskite materials are not completely stable under ambient conditions,which hinders their use in thermoelectric generators.Changes in the properties of bulk halide perovskite thermoelectrics are accompanied by partial phase transitions and surface oxidation processes.In this paper,we conducted a comprehensive study of the transport and structural properties of CsSnI_(3),which were pristine by vacuum melting followed by spark plasma sintering.The research results on the electrical transport of these materials revealed that exposure to an inert atmosphere does not deteriorate stability and the properties of the materials remain unchanged.However,prolonged exposure to air leads to a significant degradation of the electrical transport properties.Contrary to thin-film samples,the shift to the double perovskite structure from the perovskite one is limited to a specific surface layer.This change significantly influences the electrical transport of the material while maintaining the essential properties of both perovskite types.
基金funded by the Ministry of Science and Higher Education of the Russian Federation(State assign-ment-No.FEWM-2023-0012).
文摘This paper presents the results of studying the surface properties changes of a ther-moregulating coating based on polystyrene and silicafiller after proton irradiation with an en-ergy of 50 keV at afluence of 3�1015 cm�2.After proton irradiation,the values of the contact angle of wetting with water increase by 3.5%and 14.9%for polystyrene and the coating,respectively.The free surface energy(energy of the surface layer)of polystyrene and the coat-ings before and after proton irradiation was calculated using the Owens-Wendt-Rabel-Kaelble method.There was a significant increase in the polarity of the polystyrene surface(gp increased by a factor of 2.2)after proton irradiation.For the coating,an increase in gp by a factor of 3.89 was observed after proton irradiation.Structural changes in the coating were presented by IR Fourier spectroscopy.A slight decrease in the absorption intensity of all characteristic bands compared to the unirradiated sample was noted.It was found that the irradiation of the coating with protons led to the formation of macromolecules with hydroxyl,carbonyl,and carboxyl bonds,as well as the formation of dimeric and oligomeric siloxane chains.It was also found that after irradiation of a pure polystyrene sample with protons,the value of the solar absorption as increased by only 4.2%;whereas for the coating with silicafiller,the value of as increased by 28.6%.
文摘We formulated and analyzed a novel nanoformulation of the anticancer drug cisplatin （Cis） with C60 fullerene （C60＋Cis complex） and showed its higher toxicity toward tumor cell lines in vitro when compared to Cis alone. The highest toxicity of the complex was observed in HL-60/adr and HL-60/vinc chemotherapy- resistant human leukemia cell sublines （resistant to Adriamycin and Vinculin, respectively）. We discovered that the action of the C60＋Cis complex is associated with overcoming the drug resistance of the tumor cell lines through observing an increased number of apoptotic cells in the Annexin V/PI assay. Moreover, in vivo assays with Lewis lung carcinoma （LLC） C57BL/6J male mice showed that the C60＋Cis complex increases tumor growth inhibition, when compared to Cis or C60 fullerenes alone. Simultaneously, we conducted a molecular docking study and performed an Ames test. Molecular docking specifies the capability of a C60 fullerene to form van der Waals interactions with potential binding sites on P-glycoprotein （P-gp）, multidrug resistance protein 1 （MRP-1）, and multidrug resistance protein 2 （MRP-2） molecules. The observed phenomenon revealed a possible mechanism to bypass tumor cell drug resistance by the C60＋Cis complex. Additionally, the results of the Ames test show that the formation of such a complex diminishes the Cis mutagenic activity and may reduce the probability of secondary neoplasm formation. In conclusion, the C60＋Cis complex effectively induced tumor cell death in vitro and inhibited tumor growth in vivo, overcoming drug resistance likely by the potential of the C60 fullerene to interact with P-gp, MRP-1, and MRP-2 molecules. Thus, the C60＋Cis complex might be a potential novel chemotherapy modification.
