Y_(3)Al_(2)Ga_(3)O_(12):Ce^(3+),Cr^(3+)(YAGG:Ce^(3+),Cr^(3+)),as a persistent luminescent material,has advantages of high initial luminescence intensity and long persistent time,which is promising in persistent lumine...Y_(3)Al_(2)Ga_(3)O_(12):Ce^(3+),Cr^(3+)(YAGG:Ce^(3+),Cr^(3+)),as a persistent luminescent material,has advantages of high initial luminescence intensity and long persistent time,which is promising in persistent luminescent material applications.At present,YAGG:Ce^(3+),Cr^(3+)powders exhibit good persistent performance,but their persistent performance of ceramics still needs to be further improved to meet the new requirements.In this work,(Y_(0.998)Ce_(0.002))_(3)(Al_(1-x)Cr_(x))_(2)Ga_(3)O_(12) ceramics with different Cr^(3+)doping concentrations were prepared by solid-state reaction,including air pre-sintering,hot isostatic pressing(HIP)post-treatment and air annealing,to investigate the effects of Cr^(3+)doping concentration on the microstructure,optical properties and persistent performance of the ceramics.The results showed that as the doping concentration of Cr^(3+)increased from 0.025%to 0.2%(in atom),no significant effect of Cr^(3+)concentration on the morphology of pre-sintered ceramics or HIP post-treatment ceramics was observed,but the in-line transmittance gradually increased while the persistent performance gradually decreased.Among them,YAGG:Ce^(3+),Cr^(3+)ceramics doped with 0.025%Cr^(3+)showed the strongest initial luminescence intensity exceeding 6055 mcd/m^(2) and a persistent time of 1030 min after air pre-sintering combined with HIP post-treatment and air annealing.By optimizing the Cr^(3+)doping concentration and the fabrication process,the persistent luminescence(PersL)performance of the YAGG:Ce^(3+),Cr^(3+)ceramics was obviously improved.展开更多
The objective of this incubation study was to comprehensively evaluate the effects of organic fertilizer and biochar,both individually and in combination,on soil respiration dynamics,key enzyme activities and the conc...The objective of this incubation study was to comprehensively evaluate the effects of organic fertilizer and biochar,both individually and in combination,on soil respiration dynamics,key enzyme activities and the concentrations of various organic carbon components in degraded mollisol.This study used a completely randomized factorial design with three application rates of organic fertilizer(M0:0,M1:13.64 g·kg^(-1),M2:27.27 g·kg^(-1))and biochar(C0:0,C1:1.36 g·kg^(-1),C2:2.73 g·kg^(-1)),resulting in nine treatments with four replicates each.Soil CO_(2) flux,organic carbon fractions including the total,active and microbial biomass carbon,and enzyme activities(sucrase,catalase and polyphenol oxidase)were measured over 120 days.Results indicated that the factors and their interactions significantly influenced all measured parameters.Soil respiration peaked at day 15,with M1C2 treatment exhibiting a rate of 10.90-fold higher than the control.The concentrations of the total,active and microbial biomass organic carbon reached maximum values on days 60,30 and 80,respectively.Notably,M2C1 treatment yielded the highest total organic carbon(86.35%increase)and microbial biomass carbon(17.84%increase).Enzyme activities were significantly enhanced,with the highest catalase activity observed for M0C2 treatment(10.14%increase).These results demonstrated that the co-application of organic fertilizer and biochar was a effective strategy for improving soil biological health and promoting carbon sequestration in degraded mollisol.The treatment combining a high rate of organic fertilizer with a low rate of biochar(M2C1)was identified as the most promising amendment strategy for fertility restoration.展开更多
The study of non-axisymmetric fuel dispersal and detonation can provide reference for the prevention of industrial cloud explosion accidents and the design of fuel air explosive(FAE).The concentration and detonation f...The study of non-axisymmetric fuel dispersal and detonation can provide reference for the prevention of industrial cloud explosion accidents and the design of fuel air explosive(FAE).The concentration and detonation fields of 85 kg cylindrical and fan-shaped fuel are investigated by experiments and numerical simulations.A dynamic model of the whole process for fuel dispersal and detonation is built.The concentration distribution of fuel is used as the initial condition to calculate the detonation stage,thus solving the initial value problem of detonation field.The phase and component changes of fuel cloud at different locations are compared.The fuel cloud is divided into directions of 0°,90°,135°and 180°.The results show that the maximum cloud radius is 20.94 m in 135°and the minimum is 12.04 m in 0°.The diameter of the detonation fireball is 53.6 m,and the peak temperature is 3455 K.The highest peak overpressure is 3.44 MPa in 0°and the lowest is 2.97 MPa in 135°.The proportion of liquid phase in 0°is22.90%,and the fuel loss is 11.8% and 9% higher than that in 135°and cylindrical charge,respectively.The stable propagation distance of blast wave in 135°is 42.50% longer than 0°and 28.37% longer than cylindrical charge.展开更多
This paper describes numerical simulation on dispersion of the solid-liquid mixed fuel driven by explosion load. A model used in numerical calculation for dispersion of solid-liquid mixed fuel was established in this ...This paper describes numerical simulation on dispersion of the solid-liquid mixed fuel driven by explosion load. A model used in numerical calculation for dispersion of solid-liquid mixed fuel was established in this study. The concentration and turbulent intensity in the multiphase cloud of the solidliquid mixed fuel were obtained by numerical simulation. It was found that the fuel concentration tended to be 0.15 kg/m^3, the turbulence intensity tended to be 7 in 90 ms. The numerical results agree with those measured in the experiment.展开更多
Measurements of the effects of tensile stress on magnetic field properties, infrared thermography and (acoustic) emission of a cuboid sample with an elliptical hole in its center were presented. The tensile stress was...Measurements of the effects of tensile stress on magnetic field properties, infrared thermography and (acoustic) emission of a cuboid sample with an elliptical hole in its center were presented. The tensile stress was applied perpendicularly to the sample by electro-tension machine according to a step-loading curve. The changes of the sample temperature was recorded by an infrared thermography system and the noise of domain reversal was inspected by two acoustic probes, which were placed on each end of the sample near the collets of the electro-tension machine, when the sample was in loading process. The magnetic fields on the surface of the sample were inspected with 8 mm lift-off when the loads were held. Valuable information about the changes of domains was obtained from analysis of acoustic emission signals in loading process. Infrared images of the sample provided complementary information about the state of the sample. The results show that stress concentration in ferromagnetic material affects the direction and structure of domain and generates net magnetic moment on its surface. The distribution and magnitude of the net magnetic moment are correlative with those of stress.展开更多
Excess lithium in alumina is significantly bad for aluminum reduction.In this study,the concentration variation of lithium ion in sodium aluminate solution with addition of synthetic lithium aluminate was investigated...Excess lithium in alumina is significantly bad for aluminum reduction.In this study,the concentration variation of lithium ion in sodium aluminate solution with addition of synthetic lithium aluminate was investigated.Elevating temperature,increasing caustic soda concentration,reducing alumina concentration or raising molar ratioαk improved equilibrium concentration of lithium ion in sodium aluminate solution.Agitation speed had a minimal effect on lithium ion concentration.Over 0.65 g/L lithium ion equilibrium concentration was observed in digestion process,whereas 35 mg/L lithium ion concentration remained in solution after precipitation time of 9 h.Moreover,equilibrium concentration decreased sharply from digestion of boehmite or diaspore to seed precipitation,about 95%lithium was precipitated into red mud(bauxite residue)and aluminum hydroxide.This study provides a valuable perspective in removal or extraction of lithium from sodium aluminate solution in alumina refineries.展开更多
Reduction of Cr(VI)using zero-valent iron(ZVI)could not only decrease the amounts of chemicals used for reduction,but also decrease the discharge of sludge.In order to find a desirable ZVI material,reduction of Cr(VI)...Reduction of Cr(VI)using zero-valent iron(ZVI)could not only decrease the amounts of chemicals used for reduction,but also decrease the discharge of sludge.In order to find a desirable ZVI material,reduction of Cr(VI)with a relative high concentration using different kinds of ZVI powders(mainly carbon differences)including reduced Fe,grey cast iron,pig iron,nodular pig iron was carried out.Parameters such as ZVI dosage,type and size affecting on Cr(VI)reduction were firstly examined and grey cast iron was selected as a preferable reducing material,followed by pig iron.Additionally,it was found that the parameters had significant influences on experimental kinetics.Then,morphology and composition of the sample before and after reaction were characterized by SEM,EPMA and XPS analyses to disclose carbon effect on the reducibility.In order to further interpret reaction mechanism,different reaction models were constructed.It was revealed that not only the carbon content could affect the Cr(VI)reduction,but also the carbon structure had an important effect on its reduction.展开更多
Ruptures at the bottom of cartridges are a common cause of failure of ammunitions,which directly threatens the safety of weapons and shooters.Based on plastic tube theory,this study analyses the radial and axial defor...Ruptures at the bottom of cartridges are a common cause of failure of ammunitions,which directly threatens the safety of weapons and shooters.Based on plastic tube theory,this study analyses the radial and axial deformation of a cartridge,considering the radial constraint of the closed end at the bottom of the cartridge.Owing to the influence of the closed end,the bottom of a cartridge does not establish complete contact with the chamber.Owing to strain concentration in the non-contact area,this area is more amenable to the occurrence of cartridge rupture.This theory predicts the location of the fracture more accurately than the traditional theory.The maximum axial deformation of a cartridge comprises bending and friction deformation.The maximum strain at the bottom of the cartridge increased by 135%owing to the introduction of bending strain caused by the closed end.The strain distribution of a cartridge was measured using digital image correlation technology,and the measured result was consistent with the predicted results of the bending deformation theory and rupture case.The effects of wall thickness,radial clearance,friction coefficient,and axial clearance on the axial deformation of the cylinder were studied.Increasing the wall thickness and reducing radial clearance were found to reduce bending deformation;furthermore,lubrication and reduction in axial clearance reduce frictional deformation,which in turn reduce cartridge rupture.展开更多
This paper presents the analysis of two-layer cilia induced flow of Phan-Thien-Tanner(PTT) fluid with thermal and concentration effect.The Phan-Thien-Tanner fluid model has been used in the analogy of mucus present in...This paper presents the analysis of two-layer cilia induced flow of Phan-Thien-Tanner(PTT) fluid with thermal and concentration effect.The Phan-Thien-Tanner fluid model has been used in the analogy of mucus present in the respiratory tract.The two-layer model approach was used due to the Peri Ciliary liquid Layer(PCL) and Airway Ciliary Layer(ACL) present on the epithelium cell in respiratory tract.The mathematical modelling of two-layer flow problem was simplified using long wavelength and small Reynold ’ s number approximation.The resulting differential equation with moving boundary gives exact solution for velocity,temperature and concentration profiles in two layers.The change in pressure has calculated by the results of velocity profile,also the pressure rise was evaluated by the numerical integration of pressure gradient along the channel wall.The impact of physical parameters on pressure rise,velocity,temperature and concentration profile was explained by the graphs.It can be seen from graphs that velocity and temperature profile are maximum in the inner layer of fluid(PCL) and concentration profile is maximum at outer layers of fluid(ACL).展开更多
Due to the nature of ultra-short-acting opioid remifentanil of high time-varying,complex compartment model and low-accuracy of plasma concentration prediction,the traditional estimation method of population pharmacoki...Due to the nature of ultra-short-acting opioid remifentanil of high time-varying,complex compartment model and low-accuracy of plasma concentration prediction,the traditional estimation method of population pharmacokinetics parameters,nonlinear mixed effects model(NONMEM),has the abuses of tedious work and plenty of man-made jamming factors.The Elman feedback neural network was built.The relationships between the patients’plasma concentration of remifentanil and time,patient’age,gender,lean body mass,height,body surface area,sampling time,total dose,and injection rate through network training were obtained to predict the plasma concentration of remifentanil,and after that,it was compared with the results of NONMEM algorithm.In conclusion,the average error of Elman network is 6.34%,while that of NONMEM is 18.99%.The absolute average error of Elman network is 27.07%,while that of NONMEM is 38.09%.The experimental results indicate that Elman neural network could predict the plasma concentration of remifentanil rapidly and stably,with high accuracy and low error.For the characteristics of simple principle and fast computing speed,this method is suitable to data analysis of short-acting anesthesia drug population pharmacokinetic and pharmacodynamics.展开更多
Blood samples were taken from birds,from a commercial line of broiler chicken,being in a fully fed state and in fasting state for 2,4,6 hours respectively at 49 d of age and plasma very low density lipoprotein(VLDL) c...Blood samples were taken from birds,from a commercial line of broiler chicken,being in a fully fed state and in fasting state for 2,4,6 hours respectively at 49 d of age and plasma very low density lipoprotein(VLDL) concentration was measured with turbidimetric assay.The experiment results showed that the variation coefficients of plasma VLDL concentration mersured at four different times were 58.11%,74.39%,69.70%,47.83%,respectively for male broilers,and 41.82%,60.87%.59.26%,50.0%for female broilers respectively.Plasma VLDL concentration decreased with the fasting time.There was a significant positive phenotypic correlation between abdominal fat weight,percentage of abdominal fat and plasma VLDL concentration for the birds being in fully feeding state,and the correlation decreased or no longer existed for the bired being in fasting state.The conclusion was that for practically application of plasma VLDL content selected in broiler chicken breeding,blood samples should be collected from birds being in feeding state.展开更多
Environmental magnetic research on beaches and shoreline processes is limited.Therefore,we carried out environmental magnetic studies on the heavy mineral-enriched,dark-reddish sands on Cedar Beach of western Lake Eri...Environmental magnetic research on beaches and shoreline processes is limited.Therefore,we carried out environmental magnetic studies on the heavy mineral-enriched,dark-reddish sands on Cedar Beach of western Lake Erie(41.68°N,82.40°W).Magnetite has been identified as the dominant magnetic mineral of these sands.This study reveals a spatial variation in concentration of magnetite particles,distribution of展开更多
Continuous measurement of ambient PM10 was performed by TEOM at a university campus for about one year from 20 November 2007 to 29 October 2008 in Changsha city of Hunan province.Indoor PM10 and PM2.5 concentration we...Continuous measurement of ambient PM10 was performed by TEOM at a university campus for about one year from 20 November 2007 to 29 October 2008 in Changsha city of Hunan province.Indoor PM10 and PM2.5 concentration were measured by DustTrak simultaneously in order to describe the difference in concentration level and daily variations of particle mass concentration between different seasons,and to survey the influence of ambient particle on indoor air quality.During the survey period,the annual average PM10 concentration was found to be 117.63 μg/m3,with a mean value 121.88 μg/m3 in winter and 111.50 μg/m3 in spring.The temporal trend changed quickly from time to time,and the peak values were found in rush hours and in the evening.Ambient PM10 showed a good correlation with indoor PM10 and outdoor PM2.5 but not with indoor PM2.5.These results showed that PM10 was influenced by local source(such as traffic or fuel burning)and regional source.The correlation analysis has shown that ambient PM10 contributes substantial fraction to indoor PM10 but not to indoor PM2.5,which indicates other source may exist in the indoor environment.展开更多
Heavy metal concentrations in muscle and their relation to thegrowth of two marine fish species,including tonguefish( Cynoglossus arel) and mullet( Mugil cephalus),were studied. The samples were collected in Bach Dang...Heavy metal concentrations in muscle and their relation to thegrowth of two marine fish species,including tonguefish( Cynoglossus arel) and mullet( Mugil cephalus),were studied. The samples were collected in Bach Dang estuary andconcentrations of heavy metals( As,Cd,Co,Mn,Cu,Zn,Pb,and V) in muscle of the fisheswere determined. The result showed that the accumulated trend of heavy metal is different between fish species. The concentration of As,Zn,Mn,V,Cu,Pb,Co and Cd in tonguefish were 73. 7 ± 30. 6,22. 82 ± 4.87,3. 44 ± 2. 13,1. 61 ± 0. 15,0. 71 ± 0. 13,0. 45 ± 0. 24,0. 03 ± 0. 02 and 0. 02 ± 0. 02 mg·g-1,respectively. Meanwhile the concentration of Zn,As,V,Mn,Cu,Pb,Co and Cd in mullet were 83. 41 ±19. 68,9. 78 ± 1. 92,1. 36 ± 0. 54,1. 29 ± 0. 51,0. 65 ± 0. 12,0. 42 ± 0. 20,0. 06 ± 0. 03 and0. 03 ± 0. 01mg·g-1,respectively. Comparison of metal levels among thesespecies indicated that the concentrations of As and Mn in tonguefish were significantly higher than those in mullet,whereas Zn levels in mullet were found to be higher than that in tonguefish. There is no significant differences of Cd,Co,Cu,Pb and V levels in muscle between two species. Significant inversed relationshipsbetween concentration levels of metals and lengths of tonguefish were found for Mn,Cu and Zn,butnot for As,Cd,Pb,and V. There were no significant relationships between the heavy metal concentrations and the length of mullet. In general,decreasesof the heavy metal concentrations corresponded to the increases of fish body lengths,particularly for As,Co,Cu,Mn and V and the exception for Cd. Terefore reduced risks were associated with consuming biggermullet fish,and increased risks of As and Cd were associated with consuming bigger tonguefish in Bach Dang river mouth.展开更多
The paper studies on the sediment-laden flow by using MicroADV.Laboratory calibration has been conducted to determine the relationship between backscattered signal strength and sediment concentration. Based on the exp...The paper studies on the sediment-laden flow by using MicroADV.Laboratory calibration has been conducted to determine the relationship between backscattered signal strength and sediment concentration. Based on the experimental data,the interactions between sediment and fluid in open channel flow are investi- gated.The experiment shows that there exist inner relation between sediment concentration and turbulence, and the relationship is distinctry related to the diameter of particle as well as the flow co...展开更多
In soybean cotyledonary transformation,Agrobacterium infection is influenced by many factors.The cultivation stage of Agrobacterium strain and infectious concentration were studied in this research.Results showed that...In soybean cotyledonary transformation,Agrobacterium infection is influenced by many factors.The cultivation stage of Agrobacterium strain and infectious concentration were studied in this research.Results showed that the highest rate of resistant shoots was obtained when the strain cultivation concentration was OD 600 =0.6,and the infectious concentration was OD 600 =0.5.Seven soybean cultivars in North China were also screened for high susceptibility to Agrobacterium and three genotypes were found to be s...展开更多
Objective This study aimed to investigate predictability of preconception maternal circulating folate and homocysteine concentrations,glycemic and lipid profiles to the risk of congenital heart disease(CHD)in offsprin...Objective This study aimed to investigate predictability of preconception maternal circulating folate and homocysteine concentrations,glycemic and lipid profiles to the risk of congenital heart disease(CHD)in offspring.Methods A cohort of pregnancies was derived from a single hospital where pre-and post-conceptional serum folate,homocysteine,lipids,glycemic profiling and neonatal CHD screening program were facilitated.展开更多
The emulsion polymerization of aniline in three phase system of xylene functionalized protonic acid water was carried out using (NH 4) 2S 2O 4 as oxidant. The influences of water phase concentration on the viscosity, ...The emulsion polymerization of aniline in three phase system of xylene functionalized protonic acid water was carried out using (NH 4) 2S 2O 4 as oxidant. The influences of water phase concentration on the viscosity, conductivity, transmittance of polyaniline(PAN) latex and its powders were studied. The results show that the properties of PAN prepared through the emulsion polymerization are influenced by the amount of water used in the polymerization. The morphology of PAN varies with the water phase concentration used in the polymerization, which may result in the change of properties of PAN latex and its powders. When the volume fraction of water (φ) is about 20% 30%, the prepared PAN powder has higher conductivity, and the PAN latex has appropriate viscosity and particle size. The consumption of xylene was reduced at high φ value.展开更多
Change in Arctic sea ice extent is one of the indicators of global climate changes. Spatio-temporal change and change patterns can be identified using various methods to facilitate human understanding global climate c...Change in Arctic sea ice extent is one of the indicators of global climate changes. Spatio-temporal change and change patterns can be identified using various methods to facilitate human understanding global climate changes. Three empirical orthogonal function(EOF) techniques are discussed and applied to decades of sea-ice concentration(SIC) dataset in Arctic area for identifying independent patterns. It was found that: 1) discrepancies exist in magnitude and scope for each EOF pattern, however, the first two leading EOFs of variability possess high similarities in structure and shape; 2) Even though there are somewhat differences in amplitude of each PC mode, the first two leading PC modes maintain consistent in overall trend and periodicity; 3) There are significant discrepancies and inconsistencies in the third and fourth leading EOF and PC modes. The accuracies of three techniques are further validated in representing the physical phenomena of SIC anomaly patterns.展开更多
The chickens used in this study were from a pure line of brown shell egg-type (YAFA) female grandparents of 17-week-old. Plasma very low density lipoprotein (VLDL) concentration was measured with turbidimetric assay. ...The chickens used in this study were from a pure line of brown shell egg-type (YAFA) female grandparents of 17-week-old. Plasma very low density lipoprotein (VLDL) concentration was measured with turbidimetric assay. The experimental results showed that there was a close relationship between plasma VLDL concentration and egg composition traits, and a positive phenotypic correlation trend was found between 29-week plasma VLDL concentration and 44-week yolk weight, and the genetic correlation coefficient was 0.234. Both the phenotypic and genetic correlations between 29-week plasma VLDL concentration and albumen weight were negative. Significant positive phenotypie correlations were, however, observed between yolk ratio, or the yolk/albumen ratio and 29-week plasma VLDL concentration, and their genetic correlation coefficients were 0.250 and 0.223, respectively.展开更多
基金National Key R&D Program of China(2023YFB3506600)。
文摘Y_(3)Al_(2)Ga_(3)O_(12):Ce^(3+),Cr^(3+)(YAGG:Ce^(3+),Cr^(3+)),as a persistent luminescent material,has advantages of high initial luminescence intensity and long persistent time,which is promising in persistent luminescent material applications.At present,YAGG:Ce^(3+),Cr^(3+)powders exhibit good persistent performance,but their persistent performance of ceramics still needs to be further improved to meet the new requirements.In this work,(Y_(0.998)Ce_(0.002))_(3)(Al_(1-x)Cr_(x))_(2)Ga_(3)O_(12) ceramics with different Cr^(3+)doping concentrations were prepared by solid-state reaction,including air pre-sintering,hot isostatic pressing(HIP)post-treatment and air annealing,to investigate the effects of Cr^(3+)doping concentration on the microstructure,optical properties and persistent performance of the ceramics.The results showed that as the doping concentration of Cr^(3+)increased from 0.025%to 0.2%(in atom),no significant effect of Cr^(3+)concentration on the morphology of pre-sintered ceramics or HIP post-treatment ceramics was observed,but the in-line transmittance gradually increased while the persistent performance gradually decreased.Among them,YAGG:Ce^(3+),Cr^(3+)ceramics doped with 0.025%Cr^(3+)showed the strongest initial luminescence intensity exceeding 6055 mcd/m^(2) and a persistent time of 1030 min after air pre-sintering combined with HIP post-treatment and air annealing.By optimizing the Cr^(3+)doping concentration and the fabrication process,the persistent luminescence(PersL)performance of the YAGG:Ce^(3+),Cr^(3+)ceramics was obviously improved.
基金Supported by the Special Fund for Agro-scientific Research in Public Interest in China(201503119-06-01)。
文摘The objective of this incubation study was to comprehensively evaluate the effects of organic fertilizer and biochar,both individually and in combination,on soil respiration dynamics,key enzyme activities and the concentrations of various organic carbon components in degraded mollisol.This study used a completely randomized factorial design with three application rates of organic fertilizer(M0:0,M1:13.64 g·kg^(-1),M2:27.27 g·kg^(-1))and biochar(C0:0,C1:1.36 g·kg^(-1),C2:2.73 g·kg^(-1)),resulting in nine treatments with four replicates each.Soil CO_(2) flux,organic carbon fractions including the total,active and microbial biomass carbon,and enzyme activities(sucrase,catalase and polyphenol oxidase)were measured over 120 days.Results indicated that the factors and their interactions significantly influenced all measured parameters.Soil respiration peaked at day 15,with M1C2 treatment exhibiting a rate of 10.90-fold higher than the control.The concentrations of the total,active and microbial biomass organic carbon reached maximum values on days 60,30 and 80,respectively.Notably,M2C1 treatment yielded the highest total organic carbon(86.35%increase)and microbial biomass carbon(17.84%increase).Enzyme activities were significantly enhanced,with the highest catalase activity observed for M0C2 treatment(10.14%increase).These results demonstrated that the co-application of organic fertilizer and biochar was a effective strategy for improving soil biological health and promoting carbon sequestration in degraded mollisol.The treatment combining a high rate of organic fertilizer with a low rate of biochar(M2C1)was identified as the most promising amendment strategy for fertility restoration.
基金supported by the National Key Research and Development Program of China (Grant No.2021YFC3001204)。
文摘The study of non-axisymmetric fuel dispersal and detonation can provide reference for the prevention of industrial cloud explosion accidents and the design of fuel air explosive(FAE).The concentration and detonation fields of 85 kg cylindrical and fan-shaped fuel are investigated by experiments and numerical simulations.A dynamic model of the whole process for fuel dispersal and detonation is built.The concentration distribution of fuel is used as the initial condition to calculate the detonation stage,thus solving the initial value problem of detonation field.The phase and component changes of fuel cloud at different locations are compared.The fuel cloud is divided into directions of 0°,90°,135°and 180°.The results show that the maximum cloud radius is 20.94 m in 135°and the minimum is 12.04 m in 0°.The diameter of the detonation fireball is 53.6 m,and the peak temperature is 3455 K.The highest peak overpressure is 3.44 MPa in 0°and the lowest is 2.97 MPa in 135°.The proportion of liquid phase in 0°is22.90%,and the fuel loss is 11.8% and 9% higher than that in 135°and cylindrical charge,respectively.The stable propagation distance of blast wave in 135°is 42.50% longer than 0°and 28.37% longer than cylindrical charge.
基金supported by National Key R&D Program of China(No.2016YFC0801800)the opening project of State Key Laboratory of Explosion Science and Technology(Beijing Institute ofTechnology)(No.KFJJ18-03M)
文摘This paper describes numerical simulation on dispersion of the solid-liquid mixed fuel driven by explosion load. A model used in numerical calculation for dispersion of solid-liquid mixed fuel was established in this study. The concentration and turbulent intensity in the multiphase cloud of the solidliquid mixed fuel were obtained by numerical simulation. It was found that the fuel concentration tended to be 0.15 kg/m^3, the turbulence intensity tended to be 7 in 90 ms. The numerical results agree with those measured in the experiment.
文摘Measurements of the effects of tensile stress on magnetic field properties, infrared thermography and (acoustic) emission of a cuboid sample with an elliptical hole in its center were presented. The tensile stress was applied perpendicularly to the sample by electro-tension machine according to a step-loading curve. The changes of the sample temperature was recorded by an infrared thermography system and the noise of domain reversal was inspected by two acoustic probes, which were placed on each end of the sample near the collets of the electro-tension machine, when the sample was in loading process. The magnetic fields on the surface of the sample were inspected with 8 mm lift-off when the loads were held. Valuable information about the changes of domains was obtained from analysis of acoustic emission signals in loading process. Infrared images of the sample provided complementary information about the state of the sample. The results show that stress concentration in ferromagnetic material affects the direction and structure of domain and generates net magnetic moment on its surface. The distribution and magnitude of the net magnetic moment are correlative with those of stress.
基金Project(2015BAB04B01)supported by the National Key Technology R&D Program of ChinaProject(FA2017029)supported by Science and Technology Program of Chongzuo,ChinaProject(CSUZC201811)supported by the Open-End Fund for the Valuable and Precision Instruments of Central South University,China
文摘Excess lithium in alumina is significantly bad for aluminum reduction.In this study,the concentration variation of lithium ion in sodium aluminate solution with addition of synthetic lithium aluminate was investigated.Elevating temperature,increasing caustic soda concentration,reducing alumina concentration or raising molar ratioαk improved equilibrium concentration of lithium ion in sodium aluminate solution.Agitation speed had a minimal effect on lithium ion concentration.Over 0.65 g/L lithium ion equilibrium concentration was observed in digestion process,whereas 35 mg/L lithium ion concentration remained in solution after precipitation time of 9 h.Moreover,equilibrium concentration decreased sharply from digestion of boehmite or diaspore to seed precipitation,about 95%lithium was precipitated into red mud(bauxite residue)and aluminum hydroxide.This study provides a valuable perspective in removal or extraction of lithium from sodium aluminate solution in alumina refineries.
基金Project(51604131)supported by the National Natural Science Foundation of ChinaProject(2017FB084)supported by the Yunnan Province Applied Basic Research,China+1 种基金Project(KKSY201563041)supported by the Talent&Training Program of Yunnan Province,ChinaProjects(2017T20090159,2018T20150055)supported by the Testing and Analyzing Funds of Kunming University of Science and Technology,China
文摘Reduction of Cr(VI)using zero-valent iron(ZVI)could not only decrease the amounts of chemicals used for reduction,but also decrease the discharge of sludge.In order to find a desirable ZVI material,reduction of Cr(VI)with a relative high concentration using different kinds of ZVI powders(mainly carbon differences)including reduced Fe,grey cast iron,pig iron,nodular pig iron was carried out.Parameters such as ZVI dosage,type and size affecting on Cr(VI)reduction were firstly examined and grey cast iron was selected as a preferable reducing material,followed by pig iron.Additionally,it was found that the parameters had significant influences on experimental kinetics.Then,morphology and composition of the sample before and after reaction were characterized by SEM,EPMA and XPS analyses to disclose carbon effect on the reducibility.In order to further interpret reaction mechanism,different reaction models were constructed.It was revealed that not only the carbon content could affect the Cr(VI)reduction,but also the carbon structure had an important effect on its reduction.
基金The authors are grateful for the reviewers’instructive suggestions and careful proofreading.This work was supported by the Equipment Development Department of the Central Military Commission of China(grant nos.301090702)the Foundation of National Laboratory(grant nos.61426060102162606005 and JCKYS2019209C001).
文摘Ruptures at the bottom of cartridges are a common cause of failure of ammunitions,which directly threatens the safety of weapons and shooters.Based on plastic tube theory,this study analyses the radial and axial deformation of a cartridge,considering the radial constraint of the closed end at the bottom of the cartridge.Owing to the influence of the closed end,the bottom of a cartridge does not establish complete contact with the chamber.Owing to strain concentration in the non-contact area,this area is more amenable to the occurrence of cartridge rupture.This theory predicts the location of the fracture more accurately than the traditional theory.The maximum axial deformation of a cartridge comprises bending and friction deformation.The maximum strain at the bottom of the cartridge increased by 135%owing to the introduction of bending strain caused by the closed end.The strain distribution of a cartridge was measured using digital image correlation technology,and the measured result was consistent with the predicted results of the bending deformation theory and rupture case.The effects of wall thickness,radial clearance,friction coefficient,and axial clearance on the axial deformation of the cylinder were studied.Increasing the wall thickness and reducing radial clearance were found to reduce bending deformation;furthermore,lubrication and reduction in axial clearance reduce frictional deformation,which in turn reduce cartridge rupture.
文摘This paper presents the analysis of two-layer cilia induced flow of Phan-Thien-Tanner(PTT) fluid with thermal and concentration effect.The Phan-Thien-Tanner fluid model has been used in the analogy of mucus present in the respiratory tract.The two-layer model approach was used due to the Peri Ciliary liquid Layer(PCL) and Airway Ciliary Layer(ACL) present on the epithelium cell in respiratory tract.The mathematical modelling of two-layer flow problem was simplified using long wavelength and small Reynold ’ s number approximation.The resulting differential equation with moving boundary gives exact solution for velocity,temperature and concentration profiles in two layers.The change in pressure has calculated by the results of velocity profile,also the pressure rise was evaluated by the numerical integration of pressure gradient along the channel wall.The impact of physical parameters on pressure rise,velocity,temperature and concentration profile was explained by the graphs.It can be seen from graphs that velocity and temperature profile are maximum in the inner layer of fluid(PCL) and concentration profile is maximum at outer layers of fluid(ACL).
基金Project(31200748)supported by the National Natural Science Foundation of China
文摘Due to the nature of ultra-short-acting opioid remifentanil of high time-varying,complex compartment model and low-accuracy of plasma concentration prediction,the traditional estimation method of population pharmacokinetics parameters,nonlinear mixed effects model(NONMEM),has the abuses of tedious work and plenty of man-made jamming factors.The Elman feedback neural network was built.The relationships between the patients’plasma concentration of remifentanil and time,patient’age,gender,lean body mass,height,body surface area,sampling time,total dose,and injection rate through network training were obtained to predict the plasma concentration of remifentanil,and after that,it was compared with the results of NONMEM algorithm.In conclusion,the average error of Elman network is 6.34%,while that of NONMEM is 18.99%.The absolute average error of Elman network is 27.07%,while that of NONMEM is 38.09%.The experimental results indicate that Elman neural network could predict the plasma concentration of remifentanil rapidly and stably,with high accuracy and low error.For the characteristics of simple principle and fast computing speed,this method is suitable to data analysis of short-acting anesthesia drug population pharmacokinetic and pharmacodynamics.
文摘Blood samples were taken from birds,from a commercial line of broiler chicken,being in a fully fed state and in fasting state for 2,4,6 hours respectively at 49 d of age and plasma very low density lipoprotein(VLDL) concentration was measured with turbidimetric assay.The experiment results showed that the variation coefficients of plasma VLDL concentration mersured at four different times were 58.11%,74.39%,69.70%,47.83%,respectively for male broilers,and 41.82%,60.87%.59.26%,50.0%for female broilers respectively.Plasma VLDL concentration decreased with the fasting time.There was a significant positive phenotypic correlation between abdominal fat weight,percentage of abdominal fat and plasma VLDL concentration for the birds being in fully feeding state,and the correlation decreased or no longer existed for the bired being in fasting state.The conclusion was that for practically application of plasma VLDL content selected in broiler chicken breeding,blood samples should be collected from birds being in feeding state.
文摘Environmental magnetic research on beaches and shoreline processes is limited.Therefore,we carried out environmental magnetic studies on the heavy mineral-enriched,dark-reddish sands on Cedar Beach of western Lake Erie(41.68°N,82.40°W).Magnetite has been identified as the dominant magnetic mineral of these sands.This study reveals a spatial variation in concentration of magnetite particles,distribution of
基金Supported by Natural Science Foundation of China(50408019)Foundation for the Author of National Excellent Doctoral Dissertation of PR China(FANEDD200545)+1 种基金Folk Ying Tung Education Foundation(104006)Human Provincial Natural Science Foundation of China(06JJ1001)
文摘Continuous measurement of ambient PM10 was performed by TEOM at a university campus for about one year from 20 November 2007 to 29 October 2008 in Changsha city of Hunan province.Indoor PM10 and PM2.5 concentration were measured by DustTrak simultaneously in order to describe the difference in concentration level and daily variations of particle mass concentration between different seasons,and to survey the influence of ambient particle on indoor air quality.During the survey period,the annual average PM10 concentration was found to be 117.63 μg/m3,with a mean value 121.88 μg/m3 in winter and 111.50 μg/m3 in spring.The temporal trend changed quickly from time to time,and the peak values were found in rush hours and in the evening.Ambient PM10 showed a good correlation with indoor PM10 and outdoor PM2.5 but not with indoor PM2.5.These results showed that PM10 was influenced by local source(such as traffic or fuel burning)and regional source.The correlation analysis has shown that ambient PM10 contributes substantial fraction to indoor PM10 but not to indoor PM2.5,which indicates other source may exist in the indoor environment.
基金supported by Vietnam Academic of Science and Technology,No.VAST.DT.06/12-13by the Asian CORE Program of JSPS
文摘Heavy metal concentrations in muscle and their relation to thegrowth of two marine fish species,including tonguefish( Cynoglossus arel) and mullet( Mugil cephalus),were studied. The samples were collected in Bach Dang estuary andconcentrations of heavy metals( As,Cd,Co,Mn,Cu,Zn,Pb,and V) in muscle of the fisheswere determined. The result showed that the accumulated trend of heavy metal is different between fish species. The concentration of As,Zn,Mn,V,Cu,Pb,Co and Cd in tonguefish were 73. 7 ± 30. 6,22. 82 ± 4.87,3. 44 ± 2. 13,1. 61 ± 0. 15,0. 71 ± 0. 13,0. 45 ± 0. 24,0. 03 ± 0. 02 and 0. 02 ± 0. 02 mg·g-1,respectively. Meanwhile the concentration of Zn,As,V,Mn,Cu,Pb,Co and Cd in mullet were 83. 41 ±19. 68,9. 78 ± 1. 92,1. 36 ± 0. 54,1. 29 ± 0. 51,0. 65 ± 0. 12,0. 42 ± 0. 20,0. 06 ± 0. 03 and0. 03 ± 0. 01mg·g-1,respectively. Comparison of metal levels among thesespecies indicated that the concentrations of As and Mn in tonguefish were significantly higher than those in mullet,whereas Zn levels in mullet were found to be higher than that in tonguefish. There is no significant differences of Cd,Co,Cu,Pb and V levels in muscle between two species. Significant inversed relationshipsbetween concentration levels of metals and lengths of tonguefish were found for Mn,Cu and Zn,butnot for As,Cd,Pb,and V. There were no significant relationships between the heavy metal concentrations and the length of mullet. In general,decreasesof the heavy metal concentrations corresponded to the increases of fish body lengths,particularly for As,Co,Cu,Mn and V and the exception for Cd. Terefore reduced risks were associated with consuming biggermullet fish,and increased risks of As and Cd were associated with consuming bigger tonguefish in Bach Dang river mouth.
基金Supported by National Key Basic Research and Development Program(973 Program)(2003CB415205)the National Natural Science Foundation of China and the Research Fund for the Doctoral Program of Higher Education of the Ministry of Education of China
文摘The paper studies on the sediment-laden flow by using MicroADV.Laboratory calibration has been conducted to determine the relationship between backscattered signal strength and sediment concentration. Based on the experimental data,the interactions between sediment and fluid in open channel flow are investi- gated.The experiment shows that there exist inner relation between sediment concentration and turbulence, and the relationship is distinctry related to the diameter of particle as well as the flow co...
基金Supported by New Variety Breeding Key Project of Genetic Modified Organisms (2008ZX08004-002)Special Research Fund from Harbin Technology and Science Innovation (2008RFQXN013)Postdoctoral Fund and Doctoral Fund of Northeast Agricultural University
文摘In soybean cotyledonary transformation,Agrobacterium infection is influenced by many factors.The cultivation stage of Agrobacterium strain and infectious concentration were studied in this research.Results showed that the highest rate of resistant shoots was obtained when the strain cultivation concentration was OD 600 =0.6,and the infectious concentration was OD 600 =0.5.Seven soybean cultivars in North China were also screened for high susceptibility to Agrobacterium and three genotypes were found to be s...
文摘Objective This study aimed to investigate predictability of preconception maternal circulating folate and homocysteine concentrations,glycemic and lipid profiles to the risk of congenital heart disease(CHD)in offspring.Methods A cohort of pregnancies was derived from a single hospital where pre-and post-conceptional serum folate,homocysteine,lipids,glycemic profiling and neonatal CHD screening program were facilitated.
基金TheNaturalScienceFoundationofHunanProvince (No .98JJY2 0 6 0 )
文摘The emulsion polymerization of aniline in three phase system of xylene functionalized protonic acid water was carried out using (NH 4) 2S 2O 4 as oxidant. The influences of water phase concentration on the viscosity, conductivity, transmittance of polyaniline(PAN) latex and its powders were studied. The results show that the properties of PAN prepared through the emulsion polymerization are influenced by the amount of water used in the polymerization. The morphology of PAN varies with the water phase concentration used in the polymerization, which may result in the change of properties of PAN latex and its powders. When the volume fraction of water (φ) is about 20% 30%, the prepared PAN powder has higher conductivity, and the PAN latex has appropriate viscosity and particle size. The consumption of xylene was reduced at high φ value.
基金Project(41301420)supported by the National Natural Science Foundation of ChinaProject(12JJB005)supported by the Hunan Provincial Natural Science Foundation of China+1 种基金Project(2014VGE03)supported by the Key Lab of Virtual Geographic Environment from Ministry of Education,ChinaProject(LEND2013B04)supported by the NASA Key Laboratory of Land Environment and Disaster Monitoring,USA
文摘Change in Arctic sea ice extent is one of the indicators of global climate changes. Spatio-temporal change and change patterns can be identified using various methods to facilitate human understanding global climate changes. Three empirical orthogonal function(EOF) techniques are discussed and applied to decades of sea-ice concentration(SIC) dataset in Arctic area for identifying independent patterns. It was found that: 1) discrepancies exist in magnitude and scope for each EOF pattern, however, the first two leading EOFs of variability possess high similarities in structure and shape; 2) Even though there are somewhat differences in amplitude of each PC mode, the first two leading PC modes maintain consistent in overall trend and periodicity; 3) There are significant discrepancies and inconsistencies in the third and fourth leading EOF and PC modes. The accuracies of three techniques are further validated in representing the physical phenomena of SIC anomaly patterns.
文摘The chickens used in this study were from a pure line of brown shell egg-type (YAFA) female grandparents of 17-week-old. Plasma very low density lipoprotein (VLDL) concentration was measured with turbidimetric assay. The experimental results showed that there was a close relationship between plasma VLDL concentration and egg composition traits, and a positive phenotypic correlation trend was found between 29-week plasma VLDL concentration and 44-week yolk weight, and the genetic correlation coefficient was 0.234. Both the phenotypic and genetic correlations between 29-week plasma VLDL concentration and albumen weight were negative. Significant positive phenotypie correlations were, however, observed between yolk ratio, or the yolk/albumen ratio and 29-week plasma VLDL concentration, and their genetic correlation coefficients were 0.250 and 0.223, respectively.
