Purpose–This paper aims to obtain the evolution law of dynamic performance of CR400BF electric multiple unit(EMU).Design/methodology/approach–Using the dynamic simulation based on field test,stiffness of rotary arm ...Purpose–This paper aims to obtain the evolution law of dynamic performance of CR400BF electric multiple unit(EMU).Design/methodology/approach–Using the dynamic simulation based on field test,stiffness of rotary arm nodes and damping coefficient of anti-hunting dampers were tested.Stiffness,damping coefficient,friction coefficient,track gauge were taken as random variables,the stochastic dynamics simulation method was constructed and applied to research the evolution law with running mileage of dynamic index of CR400BF EMU.Findings–The results showed that stiffness and damping coefficient subjected to normal distribution,the mean and variance were computed and the evolution law of stiffness and damping coefficient with running mileage was obtained.Originality/value–Firstly,based on the field test we found that stiffness of rotary arm nodes and damping coefficient of anti-hunting dampers subjected to normal distribution,and the evolution law of stiffness and damping coefficient with running mileage was proposed.Secondly stiffness,damping coefficient,friction coefficient,track gauge were taken as random variables,the stochastic dynamics simulation method was constructed and applied to the research to the evolution law with running mileage of dynamic index of CR400BF EMU.展开更多
Substrate is an important abiotic factor for burrowing shellfish,as it not only provides them with shelter,but also impose significant effect on their physiological metabolism.However,the physiological responses of bu...Substrate is an important abiotic factor for burrowing shellfish,as it not only provides them with shelter,but also impose significant effect on their physiological metabolism.However,the physiological responses of burrowing clams within various substrates get less attention due to difficulty in carrying out physiological tests in buried conditions.Consequently,this study investigated the burrowing behavior,feeding physiology and energy budget of Paphia undulata,which is an important aquaculture bivalve species in south China.The clams were exposed to mud and sand substrates with variable physical properties in the laboratory,to determine the suitable substrate conditions for this species.The results showed that the percentage of burrowing clams,digging index,burrowing time,burrowing depth and scope for growth(SFG)were higher in mud substrates with≥40%water content.Likewise,burrowing percentage,digging index,and burrowing depths were higher in substrates with≤40%sand content.Moreover,the burrowing depth had significant effect on the feeding physiology and SFG of P.undulata as clams burrowed at 6.3±1.8 cm had higher clearance rates and SFG as compared to other buried depths.This study further revealed that low water content in the sediment inhibited physiological performances of P.undulata by impairing feeding or absorption,hence reducing the SFG.In conclusion,mud substrate with≥40%water content or with≤40%sand content is suitable for proper burrowing and growth of P.undulata.Our findings therefore provide fundamental knowledge that will be applicable in the improvement of bottom aquaculture and conservation of P.undulata.展开更多
[Objectives]miRNAs play an important role in the proliferation and differentiation of different myoblasts.This study was conducted to elucidate the complex genetic mechanisms that affect the meat production performanc...[Objectives]miRNAs play an important role in the proliferation and differentiation of different myoblasts.This study was conducted to elucidate the complex genetic mechanisms that affect the meat production performance of Sichuan white rabbits and reveal the regulatory role of miRNAs in their muscle growth and meat quality formation.[Methods]Three constructed skeletal muscle libraries of Sichuan white rabbits aged six months were sequenced by the solexa technology to identify known miRNAs,predict new miRNAs and construct an expression profile of muscle miRNAs.[Results]A total of 511 known miRNAs and 42 miRNAs were detected in 34089472 pure sequences,and the proportion of miRNAs with a length of 22 nt was the highest.The number of known miRNA sequences accounted for 71.38%of pure sequences,which was much higher than the proportion of other types of RNAs.The proportion of sequences from exons was 0.38%,indicating a low degree of mRNA degradation in the samples.Base U had the highest proportion at the first position,and the bases with the highest proportions at positions 8 and 10 were U and A,respectively.Muscle-specific miRNAs(miR-1,miR-133,and miR-206)ranked in the top 10 in terms of expression level.The number and expression levels of new miRNAs were lower than those of known miRNAs.The length distribution,base bias at different positions and expression profile characteristics of miRNAs might be related to the biological function of miRNAs in regulating muscle proliferation and differentiation and the action mechanisms with target genes.[Conclusions]The identification and expression of miRNAs in muscle tissues of Sichuan white rabbits will help to understand the complex molecular mechanisms of meat production performance and provide a theoretical basis for the functional research of miRNAs in meat rabbits.展开更多
The solubility of meropenem trihydrate in water+acetone mixtures and water+tetrahydrofuran mixtures were determined from T=(278.15 to 303.15) K by static method under atmospheric pressure.Effects of solvent compositio...The solubility of meropenem trihydrate in water+acetone mixtures and water+tetrahydrofuran mixtures were determined from T=(278.15 to 303.15) K by static method under atmospheric pressure.Effects of solvent composition and temperature on solubility of meropenem trihydrate were discussed.To extend the applicability of the solubility data,experimental solubility data in two kinds of binary solvent mixtures were correlated by the Apelblat equation and NIBS/Redlich–Kister model.It was found that the two models could satisfactorily correlate the experimental data and the Apelblat equation could give better correlation results.展开更多
By designing a metal saw structure,both negative and positive rotations of dust vortices are obtained experimentally.With increasing gas pressure,the dust vortex undergoes different spatial distribution from dense dus...By designing a metal saw structure,both negative and positive rotations of dust vortices are obtained experimentally.With increasing gas pressure,the dust vortex undergoes different spatial distribution from dense dust cloud to dust void,then to dust chain.The transition between the negative and positive rotations of dust vortices is reversible and controllable by changing the gas pressure/input power.The underlying mechanism of this transition is preliminarily explored.展开更多
The multiple jets impingement heat transfer is widely applied in the wing anti-icing system.It is challenging to apply the similarity criterion to carry out the anti-icing experiments due to the complex flow and heat ...The multiple jets impingement heat transfer is widely applied in the wing anti-icing system.It is challenging to apply the similarity criterion to carry out the anti-icing experiments due to the complex flow and heat transfer behavior.In the present study,the full-scale slat model is used to carry out anti-icing experimental researches in a 2 m×3 m icing wind tunnel of China Aerodynamics Research and Development Center.The effects of icing parameters Liquid Water Content(LWC)and Median Volume Diameter(MVD)and hot air parameters(mass flow rate and temperature)on the thermal performance of an inner-liner anti-icing system with jets impingement heat transfer are studied.The effects of the experimental parameters are analyzed in detail by combining impingement and evaporation heat transfer mechanisms.The impingement hot air mass flow rate dramatically affects the heat transfer performance of the impingement stagnation region within the range of the experimental parameters.The temperature of impingement hot air and that of wing skin are approximately linear correlated.The experimental results show the effects of LWC and MVD on water film formation and runback ice accretion.The formation of water film is analyzed by an analytical method based on the wing skin temperature difference of dry and wet air conditions.展开更多
Ultra-fine-grained commercial purity aluminum was produced by severe cold rolling, annealing and then strain- ing at ultra-high rate by a single pass laser shock. Resulted microstructure was investigated by transmissi...Ultra-fine-grained commercial purity aluminum was produced by severe cold rolling, annealing and then strain- ing at ultra-high rate by a single pass laser shock. Resulted microstructure was investigated by transmission electron microscopy. Microhardness of annealed 0.6 μm ultra-fine grained aluminum increased by 67% from 24 to 40 HV. Many 0.3 μm sub-grains appeared at the shock wave center after a single pass laser shock, while high density dislocation networks were observed in some grains at the shock wave edges. Accordingly, microhardness at the impact center increased by 37.5% from 40 to 55 HV. From the impact center to the edge, microhardness decreased by 22% from 55 to 45 HV.展开更多
基金Science and Technology Development Project Agreement/Contract,China National Railway Group Co.,Ltd.(N2023J012)support by China Academy of Railway Sciences Corporation Limited(2021YJ208).
文摘Purpose–This paper aims to obtain the evolution law of dynamic performance of CR400BF electric multiple unit(EMU).Design/methodology/approach–Using the dynamic simulation based on field test,stiffness of rotary arm nodes and damping coefficient of anti-hunting dampers were tested.Stiffness,damping coefficient,friction coefficient,track gauge were taken as random variables,the stochastic dynamics simulation method was constructed and applied to research the evolution law with running mileage of dynamic index of CR400BF EMU.Findings–The results showed that stiffness and damping coefficient subjected to normal distribution,the mean and variance were computed and the evolution law of stiffness and damping coefficient with running mileage was obtained.Originality/value–Firstly,based on the field test we found that stiffness of rotary arm nodes and damping coefficient of anti-hunting dampers subjected to normal distribution,and the evolution law of stiffness and damping coefficient with running mileage was proposed.Secondly stiffness,damping coefficient,friction coefficient,track gauge were taken as random variables,the stochastic dynamics simulation method was constructed and applied to the research to the evolution law with running mileage of dynamic index of CR400BF EMU.
基金Supported by the Guangxi Science and Technology Base and Talent Special Project (No.AD23026114)。
文摘Substrate is an important abiotic factor for burrowing shellfish,as it not only provides them with shelter,but also impose significant effect on their physiological metabolism.However,the physiological responses of burrowing clams within various substrates get less attention due to difficulty in carrying out physiological tests in buried conditions.Consequently,this study investigated the burrowing behavior,feeding physiology and energy budget of Paphia undulata,which is an important aquaculture bivalve species in south China.The clams were exposed to mud and sand substrates with variable physical properties in the laboratory,to determine the suitable substrate conditions for this species.The results showed that the percentage of burrowing clams,digging index,burrowing time,burrowing depth and scope for growth(SFG)were higher in mud substrates with≥40%water content.Likewise,burrowing percentage,digging index,and burrowing depths were higher in substrates with≤40%sand content.Moreover,the burrowing depth had significant effect on the feeding physiology and SFG of P.undulata as clams burrowed at 6.3±1.8 cm had higher clearance rates and SFG as compared to other buried depths.This study further revealed that low water content in the sediment inhibited physiological performances of P.undulata by impairing feeding or absorption,hence reducing the SFG.In conclusion,mud substrate with≥40%water content or with≤40%sand content is suitable for proper burrowing and growth of P.undulata.Our findings therefore provide fundamental knowledge that will be applicable in the improvement of bottom aquaculture and conservation of P.undulata.
基金Supported by Science and Technology Achievement Transformation Project of Scientific Research Institutions(2021JDZH0019)National Modern Agricultural Industry Technology System of the Ministry of Agriculture(CARS-43-D-1)+4 种基金Sichuan Provincial Breeding Research(2021YFYZ0033)Special Fund for Basic Scientific Research Business of Sichuan Animal Science Academy(SASA202105SASA202305)Natural Science Foundation of Sichuan Province(2023NSFSC0171)Basic Research for Application of Sichuan Provincial Science and Technology Planning Project(2021YJ0267)。
文摘[Objectives]miRNAs play an important role in the proliferation and differentiation of different myoblasts.This study was conducted to elucidate the complex genetic mechanisms that affect the meat production performance of Sichuan white rabbits and reveal the regulatory role of miRNAs in their muscle growth and meat quality formation.[Methods]Three constructed skeletal muscle libraries of Sichuan white rabbits aged six months were sequenced by the solexa technology to identify known miRNAs,predict new miRNAs and construct an expression profile of muscle miRNAs.[Results]A total of 511 known miRNAs and 42 miRNAs were detected in 34089472 pure sequences,and the proportion of miRNAs with a length of 22 nt was the highest.The number of known miRNA sequences accounted for 71.38%of pure sequences,which was much higher than the proportion of other types of RNAs.The proportion of sequences from exons was 0.38%,indicating a low degree of mRNA degradation in the samples.Base U had the highest proportion at the first position,and the bases with the highest proportions at positions 8 and 10 were U and A,respectively.Muscle-specific miRNAs(miR-1,miR-133,and miR-206)ranked in the top 10 in terms of expression level.The number and expression levels of new miRNAs were lower than those of known miRNAs.The length distribution,base bias at different positions and expression profile characteristics of miRNAs might be related to the biological function of miRNAs in regulating muscle proliferation and differentiation and the action mechanisms with target genes.[Conclusions]The identification and expression of miRNAs in muscle tissues of Sichuan white rabbits will help to understand the complex molecular mechanisms of meat production performance and provide a theoretical basis for the functional research of miRNAs in meat rabbits.
基金Supported by Tianjin Municipal Natural Science Foundation(16JCYBJC19500)China Ministry of Science and Major National Scientific Instrument Development Project(2016YFF0102503)
文摘The solubility of meropenem trihydrate in water+acetone mixtures and water+tetrahydrofuran mixtures were determined from T=(278.15 to 303.15) K by static method under atmospheric pressure.Effects of solvent composition and temperature on solubility of meropenem trihydrate were discussed.To extend the applicability of the solubility data,experimental solubility data in two kinds of binary solvent mixtures were correlated by the Apelblat equation and NIBS/Redlich–Kister model.It was found that the two models could satisfactorily correlate the experimental data and the Apelblat equation could give better correlation results.
基金supported by National Natural Science Foundation of China (No. 11975089)the Program for National Defense Science and Technology Innovation Special Zone+1 种基金the Program for Young Top-Notch Talents of Hebei ProvinceHebei Natural Science Fund (Grant No. A2017201099).
文摘By designing a metal saw structure,both negative and positive rotations of dust vortices are obtained experimentally.With increasing gas pressure,the dust vortex undergoes different spatial distribution from dense dust cloud to dust void,then to dust chain.The transition between the negative and positive rotations of dust vortices is reversible and controllable by changing the gas pressure/input power.The underlying mechanism of this transition is preliminarily explored.
基金co-supported by the National Numerical Wind Tunnel Project(No.NNW2018-ZT2B04)the “973”Program of China(No.2015CB755800)。
文摘The multiple jets impingement heat transfer is widely applied in the wing anti-icing system.It is challenging to apply the similarity criterion to carry out the anti-icing experiments due to the complex flow and heat transfer behavior.In the present study,the full-scale slat model is used to carry out anti-icing experimental researches in a 2 m×3 m icing wind tunnel of China Aerodynamics Research and Development Center.The effects of icing parameters Liquid Water Content(LWC)and Median Volume Diameter(MVD)and hot air parameters(mass flow rate and temperature)on the thermal performance of an inner-liner anti-icing system with jets impingement heat transfer are studied.The effects of the experimental parameters are analyzed in detail by combining impingement and evaporation heat transfer mechanisms.The impingement hot air mass flow rate dramatically affects the heat transfer performance of the impingement stagnation region within the range of the experimental parameters.The temperature of impingement hot air and that of wing skin are approximately linear correlated.The experimental results show the effects of LWC and MVD on water film formation and runback ice accretion.The formation of water film is analyzed by an analytical method based on the wing skin temperature difference of dry and wet air conditions.
基金support from the National Natural Science Foundation of China (No. 50801021)
文摘Ultra-fine-grained commercial purity aluminum was produced by severe cold rolling, annealing and then strain- ing at ultra-high rate by a single pass laser shock. Resulted microstructure was investigated by transmission electron microscopy. Microhardness of annealed 0.6 μm ultra-fine grained aluminum increased by 67% from 24 to 40 HV. Many 0.3 μm sub-grains appeared at the shock wave center after a single pass laser shock, while high density dislocation networks were observed in some grains at the shock wave edges. Accordingly, microhardness at the impact center increased by 37.5% from 40 to 55 HV. From the impact center to the edge, microhardness decreased by 22% from 55 to 45 HV.
