Collisions between objects are a relatively common phenomenon in nature.Analyses of collision processes can greatly contribute to solving problems such as impact-rub faults and particle impacts.The coefficient of rest...Collisions between objects are a relatively common phenomenon in nature.Analyses of collision processes can greatly contribute to solving problems such as impact-rub faults and particle impacts.The coefficient of restitution is a critical parameter in the analysis of collision processes.Many experiments have shown that the coefficient of restitution is closely related to the plate thickness,and the smaller the plate thickness,the more inaccurate the coefficient of restitution predicted by the existing model,which seriously affects the process of collision analysis.To remedy this shortcoming,this paper proposes a plate thickness influence factor with the ratio of sphere diameter to plate thickness as the variable.The plate thickness influence factor can optimize the coefficient of restitution model to effectively predict the coefficient of restitution of impacting elastoplastic spheres with finite plate thickness.Finally,the validity of the new model is verified using a large amount of experimental data.展开更多
The medium-temperature T dependence of the jet transport coefficient̂q was studied via the nuclear modification factor RAA(p_(T))and elliptical flow parameter v_(2)(p_(T))for large transverse momentum p_(T) hadrons in...The medium-temperature T dependence of the jet transport coefficient̂q was studied via the nuclear modification factor RAA(p_(T))and elliptical flow parameter v_(2)(p_(T))for large transverse momentum p_(T) hadrons in high-energy nucleus-nucleus collisions.Within a next-to-leading-order perturbative QCD parton model for hard scatterings with modified fragmentation functions due to jet quenching controlled by q,we check the suppression and azimuthal anisotropy for large p_(T) hadrons,and extract q by global fits to RAA(pT)and v_(2)(pT)data in A+A collisions at RHIC and LHC,respectively.The numerical results from the best fits show that q∕T^(3) goes down with local medium-temperature T in the parton jet trajectory.Compared with the case of a constant q∕T^(3),the going-down T dependence of q∕T^(3) makes a hard parton jet to lose more energy near T_(c) and therefore strengthens the azimuthal anisotropy for large pT hadrons.As a result,v_(2)(p_(T))for large pT hadrons was enhanced by approximately 10%to better fit the data at RHIC/LHC.Considering the first-order phase transition from QGP to the hadron phase and the additional energy loss in the hadron phase,v_(2)(p_(T))is again enhanced by 5-10%at RHIC/LHC.展开更多
In order to find optimum design parameters in earthquake engineering, an objective function is optimized. This function comprises the initial cost of a structure and the cost due to the damage of earthquakes. Intangib...In order to find optimum design parameters in earthquake engineering, an objective function is optimized. This function comprises the initial cost of a structure and the cost due to the damage of earthquakes. Intangible losses may be included in the latter, such as how much society is willing to invest to preserve a human life. In this paper, the expression of the objective function is developed in terms of the seismic design coefficient, and the aforementioned intangible loss is calculated from both the individual point of view and that of society. The calculation of the intangible is based on utility curves. Finally, optimum seismic design coefficients are calculated for a firm ground site.展开更多
A throttling experiment for the multi-hole orifice （MO） using water was conducted based on the conclusion of key parameters affecting the MO throttling performance. Testing MOs and standard orifice plates （ SO ） w...A throttling experiment for the multi-hole orifice （MO） using water was conducted based on the conclusion of key parameters affecting the MO throttling performance. Testing MOs and standard orifice plates （ SO ） were designed for the throttling experiment to compare the throttling effect using the equivalent diameter ratio （RED） and diameter ratio （RD ） as key parameters, respectively. Meanwhile, effective metrical conditions were provided for experimental accuracy. The throttling model form was determined according to the theoretical throttling model of SO. Then the unknown parameters involved were identified by experimental data. A good concordance between the modeling computation and experimental results shows a validation of the MO throtting model.展开更多
The mobility of polymer chain segments is shown to play a major role in the diffusion ofdisperse dyes in a copolymerization modified PET system, monoepoxy compoundCH_3 (CH_3),OCH_2CH--CH_2 modified PET. The rate of dy...The mobility of polymer chain segments is shown to play a major role in the diffusion ofdisperse dyes in a copolymerization modified PET system, monoepoxy compoundCH_3 (CH_3),OCH_2CH--CH_2 modified PET. The rate of dye diffusion (diffusion coefficient D) hasbeen related to the time-dependent mechanical property, dynamic loss modulus E', which iscontrolled by the mobility of chain segments. In this modified copolyester system, the variance ofamount of modifier in the copolyester fibers causes the change in disperse dye diffusion coefficientto fiber, and in the dynamic loss modulus of the fibers, but the relationship between the diffusionand the dynamic loss modulus is in agreement with the theoretical relation derived by Bell andDumbleton. The relation obtained in this paper is:Ln D=-2. 28Ln E'+26. 81展开更多
On the basis of the analysis about present water resource situation in China,the disadvantage of the for- mula of flow loss and water using coefficient on anti-seep channel which have been applying in channel de- sign...On the basis of the analysis about present water resource situation in China,the disadvantage of the for- mula of flow loss and water using coefficient on anti-seep channel which have been applying in channel de- sign and water saving irrigation administration will be indicated in the paper. The characteristics of that the loss of conveying water is changeable with the now changing have been take into account in the new formula. The formula is validated by the example of middle permeable channel (A=1.90,m=0.40). The calculate re- sult is more precision. Also some formula has been given,they can be referred to the worker of the irrigation administration.展开更多
[Objective] The aim of this study was to evaluate the economic loss caused by Zhouqu debris flow. [Method] After the large debris flows happened on August 7, 2010 in Zhouqu, Gansu Province, we collected data at the fi...[Objective] The aim of this study was to evaluate the economic loss caused by Zhouqu debris flow. [Method] After the large debris flows happened on August 7, 2010 in Zhouqu, Gansu Province, we collected data at the first time after the disaster, and then built an assessment model to estimate the potential economic losses. [Result] The total loss reached 16.57×10^2 million Yuan, in which indirect economic loss was up to 2.42×10^2 million yaun while the actual direct economic loss was around 14.15×10^2 million Yuan. [Conclusion] The proportional coefficient method is a rapid and efficient method for evaluating the indirect loss caused by disasters.展开更多
基金Supported by Joint Fund of the Ministry of Education of China (Grant No.8091B022203)Youth Talent Support Project (Grant No.2022-JCJQ-QT-059)。
文摘Collisions between objects are a relatively common phenomenon in nature.Analyses of collision processes can greatly contribute to solving problems such as impact-rub faults and particle impacts.The coefficient of restitution is a critical parameter in the analysis of collision processes.Many experiments have shown that the coefficient of restitution is closely related to the plate thickness,and the smaller the plate thickness,the more inaccurate the coefficient of restitution predicted by the existing model,which seriously affects the process of collision analysis.To remedy this shortcoming,this paper proposes a plate thickness influence factor with the ratio of sphere diameter to plate thickness as the variable.The plate thickness influence factor can optimize the coefficient of restitution model to effectively predict the coefficient of restitution of impacting elastoplastic spheres with finite plate thickness.Finally,the validity of the new model is verified using a large amount of experimental data.
基金Guangdong Major Project of Basic and Applied Basic Research(No.2020B0301030008)Science and Technology Program of Guangzhou(No.2019050001)National Science Foundation of China(Nos.12347130 and 11935007).
文摘The medium-temperature T dependence of the jet transport coefficient̂q was studied via the nuclear modification factor RAA(p_(T))and elliptical flow parameter v_(2)(p_(T))for large transverse momentum p_(T) hadrons in high-energy nucleus-nucleus collisions.Within a next-to-leading-order perturbative QCD parton model for hard scatterings with modified fragmentation functions due to jet quenching controlled by q,we check the suppression and azimuthal anisotropy for large p_(T) hadrons,and extract q by global fits to RAA(pT)and v_(2)(pT)data in A+A collisions at RHIC and LHC,respectively.The numerical results from the best fits show that q∕T^(3) goes down with local medium-temperature T in the parton jet trajectory.Compared with the case of a constant q∕T^(3),the going-down T dependence of q∕T^(3) makes a hard parton jet to lose more energy near T_(c) and therefore strengthens the azimuthal anisotropy for large pT hadrons.As a result,v_(2)(p_(T))for large pT hadrons was enhanced by approximately 10%to better fit the data at RHIC/LHC.Considering the first-order phase transition from QGP to the hadron phase and the additional energy loss in the hadron phase,v_(2)(p_(T))is again enhanced by 5-10%at RHIC/LHC.
文摘In order to find optimum design parameters in earthquake engineering, an objective function is optimized. This function comprises the initial cost of a structure and the cost due to the damage of earthquakes. Intangible losses may be included in the latter, such as how much society is willing to invest to preserve a human life. In this paper, the expression of the objective function is developed in terms of the seismic design coefficient, and the aforementioned intangible loss is calculated from both the individual point of view and that of society. The calculation of the intangible is based on utility curves. Finally, optimum seismic design coefficients are calculated for a firm ground site.
基金the National Natural Science Foundation of China(Grant No.50578049)
文摘A throttling experiment for the multi-hole orifice （MO） using water was conducted based on the conclusion of key parameters affecting the MO throttling performance. Testing MOs and standard orifice plates （ SO ） were designed for the throttling experiment to compare the throttling effect using the equivalent diameter ratio （RED） and diameter ratio （RD ） as key parameters, respectively. Meanwhile, effective metrical conditions were provided for experimental accuracy. The throttling model form was determined according to the theoretical throttling model of SO. Then the unknown parameters involved were identified by experimental data. A good concordance between the modeling computation and experimental results shows a validation of the MO throtting model.
文摘The mobility of polymer chain segments is shown to play a major role in the diffusion ofdisperse dyes in a copolymerization modified PET system, monoepoxy compoundCH_3 (CH_3),OCH_2CH--CH_2 modified PET. The rate of dye diffusion (diffusion coefficient D) hasbeen related to the time-dependent mechanical property, dynamic loss modulus E', which iscontrolled by the mobility of chain segments. In this modified copolyester system, the variance ofamount of modifier in the copolyester fibers causes the change in disperse dye diffusion coefficientto fiber, and in the dynamic loss modulus of the fibers, but the relationship between the diffusionand the dynamic loss modulus is in agreement with the theoretical relation derived by Bell andDumbleton. The relation obtained in this paper is:Ln D=-2. 28Ln E'+26. 81
文摘On the basis of the analysis about present water resource situation in China,the disadvantage of the for- mula of flow loss and water using coefficient on anti-seep channel which have been applying in channel de- sign and water saving irrigation administration will be indicated in the paper. The characteristics of that the loss of conveying water is changeable with the now changing have been take into account in the new formula. The formula is validated by the example of middle permeable channel (A=1.90,m=0.40). The calculate re- sult is more precision. Also some formula has been given,they can be referred to the worker of the irrigation administration.
基金Supported by National Key Technology Research and Development Program(2008BAK50B06)~~
文摘[Objective] The aim of this study was to evaluate the economic loss caused by Zhouqu debris flow. [Method] After the large debris flows happened on August 7, 2010 in Zhouqu, Gansu Province, we collected data at the first time after the disaster, and then built an assessment model to estimate the potential economic losses. [Result] The total loss reached 16.57×10^2 million Yuan, in which indirect economic loss was up to 2.42×10^2 million yaun while the actual direct economic loss was around 14.15×10^2 million Yuan. [Conclusion] The proportional coefficient method is a rapid and efficient method for evaluating the indirect loss caused by disasters.
