In this study, the rapidity distribution, collective flows, and nuclear stopping power in ^(197)Au+^(197)Au collisions at intermediate energies were investigated using the ultrarelativistic quantum molecular dynamics(...In this study, the rapidity distribution, collective flows, and nuclear stopping power in ^(197)Au+^(197)Au collisions at intermediate energies were investigated using the ultrarelativistic quantum molecular dynamics(UrQMD) model with GEMINI++ code. The UrQMD model was adopted to simulate the dynamic evolution of heavy-ion collisions, whereas the GEMINI++ code was used to simulate the decay of primary fragments produced by UrQMD. The calculated results were compared with the INDRA and FOPI experimental data. It was found that the rapidity distribution, collective flows, and nuclear stopping power were affected to a certain extent by the decay of primary fragments, especially at lower beam energies. Furthermore, the experimental data of the collective flows and nuclear stopping power at the investigated beam energies were better reproduced when the sequential decay effect was included.展开更多
Rural intersections account for around 30% of crashes in rural areas and 6% of all fatal crashes, representing a significant but poorly understood safety problem. Crashes at rural intersections are also problematic si...Rural intersections account for around 30% of crashes in rural areas and 6% of all fatal crashes, representing a significant but poorly understood safety problem. Crashes at rural intersections are also problematic since high speeds on intersection approaches are present which can exacerbate the impact of a crash. Additionally, rural areas are often underserved with EMS services which can further contribute to negative crash outcomes. This paper describes an analysis of driver stopping behavior at rural T-intersections using the SHRP 2 Naturalistic Driving Study data. Type of stop was used as a safety surrogate measure using full/rolling stops compared to non-stops. Time series traces were obtained for 157 drivers at 87 unique intersections resulting in 1277 samples at the stop controlled approach for T-intersections. Roadway (i.e. number of lanes, presence of skew, speed limit, presence of stop bar or other traffic control devices), driver (age, gender, speeding), and environmental characteristics (time of day, presence of rain) were reduced and included as independent variables. Results of a logistic regression model indicated drivers were less likely to stop during the nighttime. However presence of intersection lighting increased the likelihood of full/rolling stops. Presence of intersection skew was shown to negatively impact stopping behavior. Additionally drivers who were traveling over the posted speed limit upstream of the intersection approach were less likely to stop at the approach stop sign.展开更多
Uemura [1] discovered the mapping formula for Type 1 Vague events and presented an alternative problem as an example of its application. Since it is well known that the alternative problem leads to sequential Bayesian...Uemura [1] discovered the mapping formula for Type 1 Vague events and presented an alternative problem as an example of its application. Since it is well known that the alternative problem leads to sequential Bayesian inference, the flow of subsequent research was to make the mapping formula multidimensional, to introduce the concept of time, and to derive a Markov (decision) process. Furthermore, we formulated stochastic differential equations to derive them [2]. This paper refers to type 2 vague events based on a second-order mapping equation. This quadratic mapping formula gives a certain rotation named as possibility principal factor rotation by transforming a non-mapping function by a relation between two mapping functions. In addition, the derivation of the Type 2 Complex Markov process and the initial and stopping conditions in this rotation are mentioned. .展开更多
The existing constructions of quasi-cyclic low-density parity-check (QC-LDPC) codes do not consider the problems of small stopping sets and small girth together in the Tanner graph, while their existences will lead ...The existing constructions of quasi-cyclic low-density parity-check (QC-LDPC) codes do not consider the problems of small stopping sets and small girth together in the Tanner graph, while their existences will lead to the bit error rate (BER) performance of QC-LDPC codes being much poorer than that of randomly constructed LDPC codes even decoding failure. To solve the problem, some theorems of the specific chosen parity-check matrix of QC-LDPC codes without small stopping sets and small girth are proposed. A novel construction for QC-LDPC codes with long block lengths is presented by multiplying mmin or the multiple of mmin, which is the minimum order of the identity matrix for the chosen parity-check matrix. The simulation results show that the specific chosen parity-check matrix of QC-LDPC codes can effectively avoid specified stopping sets and small girth and exhibit excellent BER performance than random LDPC codes with the same longer codes length.展开更多
This paper gives a stylistic analysis of the poem "Stopping by Woods on a Snowy Evening" by American poet Robert Frost, and then probes how the author achieves his expected goal through attracting readers...This paper gives a stylistic analysis of the poem "Stopping by Woods on a Snowy Evening" by American poet Robert Frost, and then probes how the author achieves his expected goal through attracting readers' attention and leaving them much space to create their own imagination.展开更多
We survey quite extensively the present research status of ion-stopping in dense plasmas of potential importance for initial confinement fusion(ICF)drivenby intense and heavy ion beams,and alsofor warm dense matter(WD...We survey quite extensively the present research status of ion-stopping in dense plasmas of potential importance for initial confinement fusion(ICF)drivenby intense and heavy ion beams,and alsofor warm dense matter(WDM).First,we putemphasis on every possible mechanism involved in the shaping of the ion projectile effective charge,while losing energy in a target plasma with classical ions and partially degenerate electrons.Then,we switch to ion stopping by target bound electrons,taking detailed account of mean excitation energies.Free electron stopping has already been given a lot of attention in former works[C.Deutsch et al.,Recent Res.Devel.Plasma 1(2000)1-23;Open Plasma Phys.J.3(2010)88-115].Then,we extend the usual standard stopping model(SSM)framework to nonlinear stopping including a treatment of the Z 3 Barkas effect and a confronting comparison of Bloch and Bohr Coulomb logarithms.Finally,we document low velocity ion slowing down(LVISD)in single ion plasmas as well as in binary ionic mixtures(BIM),in connection with specific ICF fuels.展开更多
Close-distance coal seams are widely distributed over China,and the coal pillars left by the overlying coal seams afect the retracement channel of the underlying coal seam in the stopping stage.Based on the engineerin...Close-distance coal seams are widely distributed over China,and the coal pillars left by the overlying coal seams afect the retracement channel of the underlying coal seam in the stopping stage.Based on the engineering background of close-distance seam mining in a coal mine,the reasonable position of the underlying coal seam's stopping line and the support method of the large section roadway during stopping are investigated using feld measurements,similar simulation experiments,and numerical simulations.There are three types of location relationships between the stopping line of the underlying coal seam and the stopping line of the overlying coal seam:"externally staggered with the upper stopping line"(ESUL,stops mining under the overlying goaf),"overlapped with upper stopping line"(OUL),and"internally staggered with the upper stopping line"(ISUL,ISUL-SD for shorter internal staggered distances,ISUL-LD for longer ones).There are diferent stress arch structures in the overlying strata of the above three positions,and the stress arch evolution process exists in the process of ESUL→OUL→ISUL-SD→ISUL-LD:a front and rear double stress arch structure→the front arch gradually decreases→the front arch dies out,and the double arch synthesizes the single arch→the single-arch range expands→the nested double arch.The relationship between the stress arch structure and the position of the stopping line is evaluated as follows:(1)ESUL:the stress concentration in the roof plate of the retracement channel of the underlying coal seam is the highest,because the overburden block of the extensive collapse zone acts directly on the roof plate of the retracement channel,resulting in relative difculties in roof support.(2)OUL:although the retracement channel roof pressure is minimal,the overlying rock structure has the potential for rotation or slippage instability.(3)ISUL-SD:the pressure on the roof of the retracement channel is small and the overburden structure is stable,which is conducive to the safe retraction of the support and not limited by the width of the end-mining coal pillar.(4)ISUL-LD:it is basically the same as the condition of stopping under the non-goaf;however,it has a limitation on the width of the end-mining coal pillar.The location of the stopping line is selected as ISUL-SD,and the retraction process of the self-excavating retraction channel was adopted.A partition asymmetric support scheme which is proven by feld practice is proposed,through a comprehensive analysis of the pre-stress feld simulation of the support scheme,based on the diferent control requirements of the roof above the support and the roof of the retracement channel in the stopping area.This method realizes safe and smooth withdrawal of the support.展开更多
The ramifications of the effective mass splitting on the nuclear stopping and isospin tracer during heavy-ion collisions within the gigaelectron volt energy region are studied using an isospin-dependent quantum molecu...The ramifications of the effective mass splitting on the nuclear stopping and isospin tracer during heavy-ion collisions within the gigaelectron volt energy region are studied using an isospin-dependent quantum molecular dynamics model.Three isotope probes,i.e.,a proton,deuteron,and triton,are used to calculate the nuclear stopping.Compared to the mn*>mp*case,the mn*<mp*parameter results in a stronger stopping for protons but a weaker stopping for tritons.The calculations of the isospin tracer show that the mn*>mp*parameter results in a higher isospin mix than the mn*<mp*parameter.The rapidity and impact parameter dependences of the isospin tracer are also studied.A constraining of the effective mass splitting using the free nucleons with high rapidity and in a central rather than peripheral collision is suggested.展开更多
Leveraging energy harvesting abilities in wireless network devices has emerged as an effective way to prolong the lifetime of energy constrained systems.The system gains are usually optimized by designing resource all...Leveraging energy harvesting abilities in wireless network devices has emerged as an effective way to prolong the lifetime of energy constrained systems.The system gains are usually optimized by designing resource allocation algorithm appropriately.However,few works focus on the interaction that channel’s time-vary characters make the energy transfer inefficiently.To address this,we propose a novel system operation sequence for sensor-cloud system where the Sinks provide SWIPT for sensor nodes opportunistically during downlink phase and collect the data transmitted from sensor nodes in uplink phase.Then,the energy-efficiency maximization problem of the Sinks is presented by considering the time costs and energy consumption of channel detection.It is proved that the formulated problem is an optimal stopping process with optimal stopping rules.An optimal energy-efficiency(OEE)algorithm is designed to obtain the optimal stopping rules for SWIPT.Finally,the simulations are performed based on the OEE algorithm compared with the other two strategies to verify the effectiveness and gains in improving the system efficiency.展开更多
The existence and uniqueness results of fully coupled forward-backward stochastic differential equations with stopping time (unbounded) is obtained. One kind of comparison theorem for this kind of equations is also pr...The existence and uniqueness results of fully coupled forward-backward stochastic differential equations with stopping time (unbounded) is obtained. One kind of comparison theorem for this kind of equations is also proved.展开更多
The possibility of pressure control with the structural change of a safety valve is investigated Safety valve is commonly used as safety devices for numerous applications which include boilers,ships,industrial plant...The possibility of pressure control with the structural change of a safety valve is investigated Safety valve is commonly used as safety devices for numerous applications which include boilers,ships,industrial plants,and piping Setting and stopping pressures of a safety valve, p set and p sto ,are traditionally adjusted with a fine tuning of seat ring and valve ring heights, h sr and h vr However, it is not easy to achieve the proper setting and stopping pressures of a safety valve in practice The depth of inside and outside grooves in a valve, d i and d o are modified and their effects on setting and stopping pressures of a safety vlave are tested The most appropriate values appear 1 0 mm in d i and 0 5~1 0 mm in d o,respectively The valve ring height, h vr ,shows that the best results can be achieved at 2 3 mm for setting pressures of 0 1~0 4 MPa and 1 0 mm for setting pressures of 0 5~1 0 MPa The stopping pressures increases with the increase of seat ring height, h sr , upto certain h sr value and then becomes independent to the seat ring height This implies that there exists the optimum h sr ,which provides the largest flow rate and the proper stopping pressure Stopping pressures of a safety valve are adjusted with the seat ring and valve ring heights This study,however,demonstrated that the modification of value grooves also changes setting and stopping pressures of a safety valve Therefore,the proper selection in dimensions of the inside and outside grooves should be considered for the safety valve design展开更多
We summarize our theoretical studies for stopping power of energetic heavy ion,diatomic molecular ions and small clusters penetrating through plasmas.As a relevant research field for the heavy ion inertial confinement...We summarize our theoretical studies for stopping power of energetic heavy ion,diatomic molecular ions and small clusters penetrating through plasmas.As a relevant research field for the heavy ion inertial confinement fusion(HICF),we lay the emphasis on the dynamic po-larization and correlation effects of the constituent ion within the molecular ion and cluster for stopping power in order to disclose the role of the vicinage effect on the Coulomb explosion and energy deposition of molecules and clusters in plasma.On the other hand,as a promising scheme for ICF,both a strong laser field and an intense ion beam are used to irradiate a plasma target.So the influence of a strong laser field on stopping power is significant.We discussed a large range of laser and plasma parameters on the coulomb explosion and stopping power for correlated-ion cluster and C 60 cluster.Furthermore,in order to indicate the effects of different cluster types and sizes on the stopping power,a comparison is made for hydrogen and carbon clusters.In addition,the deflection of molecular axis for diatomic molecules during the Coulomb explosion is also given for the cases both in the presence of a laser field and laser free.Finally,a future experimental scheme is put forward to measure molecular ion stopping power in plasmas in Xi’an Jiaotong University of China.展开更多
The existence and uniqueness of solutions to backward stochastic differential equations with jumps and with unbounded stopping time as terminal under the non_Lipschitz condition are obtained. The convergence of soluti...The existence and uniqueness of solutions to backward stochastic differential equations with jumps and with unbounded stopping time as terminal under the non_Lipschitz condition are obtained. The convergence of solutions and the continuous dependence of solutions on parameters are also derived. Then the probabilistic interpretation of solutions to some kinds of quasi_linear elliptic type integro_differential equations is obtained.展开更多
Background:In this paper,we study the right time for an investor to stop the investment over a given investment horizon so as to obtain as close to the highest possible wealth as possible,according to a Logarithmic ut...Background:In this paper,we study the right time for an investor to stop the investment over a given investment horizon so as to obtain as close to the highest possible wealth as possible,according to a Logarithmic utility-maximization objective involving the portfolio in the drift and volatility terms.The problem is formulated as an optimal stopping problem,although it is non-standard in the sense that the maximum wealth involved is not adapted to the information generated over time.Methods:By delicate stochastic analysis,the problem is converted to a standard optimal stopping one involving adapted processes.Results:Numerical examples shed light on the efficiency of the theoretical results.Conclusion:Our investment problem,which includes the portfolio in the drift and volatility terms of the dynamic systems,makes the problem including multi-dimensional financial assets more realistic and meaningful.展开更多
In this work, the mass stopping power and range of protons in biological human body tissues (ovary, lung and breast) were calculated at the energy ranging from 0.04 MeV to 200 MeV using the MATLAB Program. The data re...In this work, the mass stopping power and range of protons in biological human body tissues (ovary, lung and breast) were calculated at the energy ranging from 0.04 MeV to 200 MeV using the MATLAB Program. The data relating to the densities, average atomic number to mass number and excitation energy for the present tissues were collected from ICRU Report 46. The mass stopping power was calculated by the Bethe formula. Moreover, the simple integration (continuous slowing down approximation) method was employed for calculating protons range at the tissues. The results of the mass stopping power versus energy and the range versus energy were presented graphically and the empirical formulae for calculating the mass stopping power and the ranges were obtained. The present results for mass stopping powers and ranges were compared with the results obtained by others. Good agreements were found between them, especially at the energy ranging from 3 to 200 MeV.展开更多
In this paper we consider the problem of determining the optimal time to buy an asset in a position of an uptrend or downtrend in the financial market and currency market as well as other markets. Asset price is model...In this paper we consider the problem of determining the optimal time to buy an asset in a position of an uptrend or downtrend in the financial market and currency market as well as other markets. Asset price is modeled as a geometric Brownian motion with drift being a two-state Markov chain. Based on observations of asset prices, investors want to detect the change points of price trends as accurately as possible, so that they can make the decision to buy. Using filtering techniques and stochastic analysis, we will develop the optimal boundary at which investors implement their decisions when the posterior probability process reaches a certain threshold.展开更多
The dissipation phenomenon in the heavy-ion reaction at incident energy near the Fermi energy is studied by simulating the reaction ^129Xe+^129Sn with the isospin-dependent quantum molecular dynamics model. The calcu...The dissipation phenomenon in the heavy-ion reaction at incident energy near the Fermi energy is studied by simulating the reaction ^129Xe+^129Sn with the isospin-dependent quantum molecular dynamics model. The calculations involving a proper prescription of implementing the Pauli exclusion principle show that the isotropy ratio measured by free protons emitted in the reaction at energy slightly higher than the Fermi energy is in agreement with the experimental data recently released by the INDRA collaboration. A feasible value of the Pauli-blocking factor is estimated by comparing the theoretical results with the experimental data for the energy range considered here.展开更多
With the method of Rutherford backscattering of heavy ions from heavy substrate, the stopping powers of 11B, 12C and 19F in silver film were measured at energies from 0.11-0.53 MeV / u. The results are compared with t...With the method of Rutherford backscattering of heavy ions from heavy substrate, the stopping powers of 11B, 12C and 19F in silver film were measured at energies from 0.11-0.53 MeV / u. The results are compared with the previous experimental data and the semiempirical calculations of TRIM-90.展开更多
Suppose that C is a finite collection of patterns. Observe a Markov chain until one of the patterns in C occurs as a run. This time is denoted by τ. In this paper, we aim to give an easy way to calculate the mean wai...Suppose that C is a finite collection of patterns. Observe a Markov chain until one of the patterns in C occurs as a run. This time is denoted by τ. In this paper, we aim to give an easy way to calculate the mean waiting time E(τ) and the stopping probabilities P(τ = τA)with A ∈ C, where τA is the waiting time until the pattern A appears as a run.展开更多
基金partly supported by the National Natural Science Foundation of China (Nos. U2032145 and 11875125)the National Key Research and Development Program of China (No. 2020YFE0202002)。
文摘In this study, the rapidity distribution, collective flows, and nuclear stopping power in ^(197)Au+^(197)Au collisions at intermediate energies were investigated using the ultrarelativistic quantum molecular dynamics(UrQMD) model with GEMINI++ code. The UrQMD model was adopted to simulate the dynamic evolution of heavy-ion collisions, whereas the GEMINI++ code was used to simulate the decay of primary fragments produced by UrQMD. The calculated results were compared with the INDRA and FOPI experimental data. It was found that the rapidity distribution, collective flows, and nuclear stopping power were affected to a certain extent by the decay of primary fragments, especially at lower beam energies. Furthermore, the experimental data of the collective flows and nuclear stopping power at the investigated beam energies were better reproduced when the sequential decay effect was included.
文摘Rural intersections account for around 30% of crashes in rural areas and 6% of all fatal crashes, representing a significant but poorly understood safety problem. Crashes at rural intersections are also problematic since high speeds on intersection approaches are present which can exacerbate the impact of a crash. Additionally, rural areas are often underserved with EMS services which can further contribute to negative crash outcomes. This paper describes an analysis of driver stopping behavior at rural T-intersections using the SHRP 2 Naturalistic Driving Study data. Type of stop was used as a safety surrogate measure using full/rolling stops compared to non-stops. Time series traces were obtained for 157 drivers at 87 unique intersections resulting in 1277 samples at the stop controlled approach for T-intersections. Roadway (i.e. number of lanes, presence of skew, speed limit, presence of stop bar or other traffic control devices), driver (age, gender, speeding), and environmental characteristics (time of day, presence of rain) were reduced and included as independent variables. Results of a logistic regression model indicated drivers were less likely to stop during the nighttime. However presence of intersection lighting increased the likelihood of full/rolling stops. Presence of intersection skew was shown to negatively impact stopping behavior. Additionally drivers who were traveling over the posted speed limit upstream of the intersection approach were less likely to stop at the approach stop sign.
文摘Uemura [1] discovered the mapping formula for Type 1 Vague events and presented an alternative problem as an example of its application. Since it is well known that the alternative problem leads to sequential Bayesian inference, the flow of subsequent research was to make the mapping formula multidimensional, to introduce the concept of time, and to derive a Markov (decision) process. Furthermore, we formulated stochastic differential equations to derive them [2]. This paper refers to type 2 vague events based on a second-order mapping equation. This quadratic mapping formula gives a certain rotation named as possibility principal factor rotation by transforming a non-mapping function by a relation between two mapping functions. In addition, the derivation of the Type 2 Complex Markov process and the initial and stopping conditions in this rotation are mentioned. .
基金supported by the National Natural Science Foundation of China (60572093)Specialized Research Fund for the Doctoral Program of Higher Education (20050004016)
文摘The existing constructions of quasi-cyclic low-density parity-check (QC-LDPC) codes do not consider the problems of small stopping sets and small girth together in the Tanner graph, while their existences will lead to the bit error rate (BER) performance of QC-LDPC codes being much poorer than that of randomly constructed LDPC codes even decoding failure. To solve the problem, some theorems of the specific chosen parity-check matrix of QC-LDPC codes without small stopping sets and small girth are proposed. A novel construction for QC-LDPC codes with long block lengths is presented by multiplying mmin or the multiple of mmin, which is the minimum order of the identity matrix for the chosen parity-check matrix. The simulation results show that the specific chosen parity-check matrix of QC-LDPC codes can effectively avoid specified stopping sets and small girth and exhibit excellent BER performance than random LDPC codes with the same longer codes length.
文摘This paper gives a stylistic analysis of the poem "Stopping by Woods on a Snowy Evening" by American poet Robert Frost, and then probes how the author achieves his expected goal through attracting readers' attention and leaving them much space to create their own imagination.
文摘We survey quite extensively the present research status of ion-stopping in dense plasmas of potential importance for initial confinement fusion(ICF)drivenby intense and heavy ion beams,and alsofor warm dense matter(WDM).First,we putemphasis on every possible mechanism involved in the shaping of the ion projectile effective charge,while losing energy in a target plasma with classical ions and partially degenerate electrons.Then,we switch to ion stopping by target bound electrons,taking detailed account of mean excitation energies.Free electron stopping has already been given a lot of attention in former works[C.Deutsch et al.,Recent Res.Devel.Plasma 1(2000)1-23;Open Plasma Phys.J.3(2010)88-115].Then,we extend the usual standard stopping model(SSM)framework to nonlinear stopping including a treatment of the Z 3 Barkas effect and a confronting comparison of Bloch and Bohr Coulomb logarithms.Finally,we document low velocity ion slowing down(LVISD)in single ion plasmas as well as in binary ionic mixtures(BIM),in connection with specific ICF fuels.
基金supported by the National Natural Science Foundation of China(52004286)the Fundamental Research Funds for the Central Universities(2022XJNY02)+3 种基金the National Natural Science Foundation of China(51974317,52074296)the China Postdoctoral Science Foundation(2020T130701,2019M650895)the Fundamental Research Funds for the Central Universities(2022YJSNY18,2022YJSNY09)all of which were gratefully acknowledged.
文摘Close-distance coal seams are widely distributed over China,and the coal pillars left by the overlying coal seams afect the retracement channel of the underlying coal seam in the stopping stage.Based on the engineering background of close-distance seam mining in a coal mine,the reasonable position of the underlying coal seam's stopping line and the support method of the large section roadway during stopping are investigated using feld measurements,similar simulation experiments,and numerical simulations.There are three types of location relationships between the stopping line of the underlying coal seam and the stopping line of the overlying coal seam:"externally staggered with the upper stopping line"(ESUL,stops mining under the overlying goaf),"overlapped with upper stopping line"(OUL),and"internally staggered with the upper stopping line"(ISUL,ISUL-SD for shorter internal staggered distances,ISUL-LD for longer ones).There are diferent stress arch structures in the overlying strata of the above three positions,and the stress arch evolution process exists in the process of ESUL→OUL→ISUL-SD→ISUL-LD:a front and rear double stress arch structure→the front arch gradually decreases→the front arch dies out,and the double arch synthesizes the single arch→the single-arch range expands→the nested double arch.The relationship between the stress arch structure and the position of the stopping line is evaluated as follows:(1)ESUL:the stress concentration in the roof plate of the retracement channel of the underlying coal seam is the highest,because the overburden block of the extensive collapse zone acts directly on the roof plate of the retracement channel,resulting in relative difculties in roof support.(2)OUL:although the retracement channel roof pressure is minimal,the overlying rock structure has the potential for rotation or slippage instability.(3)ISUL-SD:the pressure on the roof of the retracement channel is small and the overburden structure is stable,which is conducive to the safe retraction of the support and not limited by the width of the end-mining coal pillar.(4)ISUL-LD:it is basically the same as the condition of stopping under the non-goaf;however,it has a limitation on the width of the end-mining coal pillar.The location of the stopping line is selected as ISUL-SD,and the retraction process of the self-excavating retraction channel was adopted.A partition asymmetric support scheme which is proven by feld practice is proposed,through a comprehensive analysis of the pre-stress feld simulation of the support scheme,based on the diferent control requirements of the roof above the support and the roof of the retracement channel in the stopping area.This method realizes safe and smooth withdrawal of the support.
基金the National Natural Science Foundation of China(Nos.11905018 and 11875328)the Scientific and Technological Innovation Programs of Higher Education Institutions of Shanxi Province,China(No.2019L0908)。
文摘The ramifications of the effective mass splitting on the nuclear stopping and isospin tracer during heavy-ion collisions within the gigaelectron volt energy region are studied using an isospin-dependent quantum molecular dynamics model.Three isotope probes,i.e.,a proton,deuteron,and triton,are used to calculate the nuclear stopping.Compared to the mn*>mp*case,the mn*<mp*parameter results in a stronger stopping for protons but a weaker stopping for tritons.The calculations of the isospin tracer show that the mn*>mp*parameter results in a higher isospin mix than the mn*<mp*parameter.The rapidity and impact parameter dependences of the isospin tracer are also studied.A constraining of the effective mass splitting using the free nucleons with high rapidity and in a central rather than peripheral collision is suggested.
基金This work was supported by Scientific Research Ability Improving Foundation for Young and Middle-Aged University Teachers in Guangxi(No.2020KY04030)The school introduces talents to start scientific research projects(No.2019KJQD17)+1 种基金This work was supported in part by the National Natural Science Foundation of China(No.61762010,No.61862007)Guangxi Natural Science Foundation(No.2018GXNSFAA138147).
文摘Leveraging energy harvesting abilities in wireless network devices has emerged as an effective way to prolong the lifetime of energy constrained systems.The system gains are usually optimized by designing resource allocation algorithm appropriately.However,few works focus on the interaction that channel’s time-vary characters make the energy transfer inefficiently.To address this,we propose a novel system operation sequence for sensor-cloud system where the Sinks provide SWIPT for sensor nodes opportunistically during downlink phase and collect the data transmitted from sensor nodes in uplink phase.Then,the energy-efficiency maximization problem of the Sinks is presented by considering the time costs and energy consumption of channel detection.It is proved that the formulated problem is an optimal stopping process with optimal stopping rules.An optimal energy-efficiency(OEE)algorithm is designed to obtain the optimal stopping rules for SWIPT.Finally,the simulations are performed based on the OEE algorithm compared with the other two strategies to verify the effectiveness and gains in improving the system efficiency.
基金This work was supported by the National Natural Science Foundation of China (10001022 and 10371067)the Excellent Young Teachers Program and the Doctoral program Foundation of MOE and Shandong Province,P.R.C.
文摘The existence and uniqueness results of fully coupled forward-backward stochastic differential equations with stopping time (unbounded) is obtained. One kind of comparison theorem for this kind of equations is also proved.
文摘The possibility of pressure control with the structural change of a safety valve is investigated Safety valve is commonly used as safety devices for numerous applications which include boilers,ships,industrial plants,and piping Setting and stopping pressures of a safety valve, p set and p sto ,are traditionally adjusted with a fine tuning of seat ring and valve ring heights, h sr and h vr However, it is not easy to achieve the proper setting and stopping pressures of a safety valve in practice The depth of inside and outside grooves in a valve, d i and d o are modified and their effects on setting and stopping pressures of a safety vlave are tested The most appropriate values appear 1 0 mm in d i and 0 5~1 0 mm in d o,respectively The valve ring height, h vr ,shows that the best results can be achieved at 2 3 mm for setting pressures of 0 1~0 4 MPa and 1 0 mm for setting pressures of 0 5~1 0 MPa The stopping pressures increases with the increase of seat ring height, h sr , upto certain h sr value and then becomes independent to the seat ring height This implies that there exists the optimum h sr ,which provides the largest flow rate and the proper stopping pressure Stopping pressures of a safety valve are adjusted with the seat ring and valve ring heights This study,however,demonstrated that the modification of value grooves also changes setting and stopping pressures of a safety valve Therefore,the proper selection in dimensions of the inside and outside grooves should be considered for the safety valve design
基金This work is jointly supported by the National Natural Science Foundation of China(Grant Nos.11375034,11404048,11604038,11705141,11775282,U1532263)program for Liaoning Excellent Talents in University(Grant No.LJQ2014051)+1 种基金the Fundamental Research Funds for the Central Universities of China(Grant Nos.3132017065,3132017071,3132017060)Science Challenge Project(Grant No.TZ2016005.)。
文摘We summarize our theoretical studies for stopping power of energetic heavy ion,diatomic molecular ions and small clusters penetrating through plasmas.As a relevant research field for the heavy ion inertial confinement fusion(HICF),we lay the emphasis on the dynamic po-larization and correlation effects of the constituent ion within the molecular ion and cluster for stopping power in order to disclose the role of the vicinage effect on the Coulomb explosion and energy deposition of molecules and clusters in plasma.On the other hand,as a promising scheme for ICF,both a strong laser field and an intense ion beam are used to irradiate a plasma target.So the influence of a strong laser field on stopping power is significant.We discussed a large range of laser and plasma parameters on the coulomb explosion and stopping power for correlated-ion cluster and C 60 cluster.Furthermore,in order to indicate the effects of different cluster types and sizes on the stopping power,a comparison is made for hydrogen and carbon clusters.In addition,the deflection of molecular axis for diatomic molecules during the Coulomb explosion is also given for the cases both in the presence of a laser field and laser free.Finally,a future experimental scheme is put forward to measure molecular ion stopping power in plasmas in Xi’an Jiaotong University of China.
文摘The existence and uniqueness of solutions to backward stochastic differential equations with jumps and with unbounded stopping time as terminal under the non_Lipschitz condition are obtained. The convergence of solutions and the continuous dependence of solutions on parameters are also derived. Then the probabilistic interpretation of solutions to some kinds of quasi_linear elliptic type integro_differential equations is obtained.
基金This work is supported by Research Grants Council of Hong Kong under grant no.519913 and 15224215National Natural Science Foundation of China(No.11571124).
文摘Background:In this paper,we study the right time for an investor to stop the investment over a given investment horizon so as to obtain as close to the highest possible wealth as possible,according to a Logarithmic utility-maximization objective involving the portfolio in the drift and volatility terms.The problem is formulated as an optimal stopping problem,although it is non-standard in the sense that the maximum wealth involved is not adapted to the information generated over time.Methods:By delicate stochastic analysis,the problem is converted to a standard optimal stopping one involving adapted processes.Results:Numerical examples shed light on the efficiency of the theoretical results.Conclusion:Our investment problem,which includes the portfolio in the drift and volatility terms of the dynamic systems,makes the problem including multi-dimensional financial assets more realistic and meaningful.
文摘In this work, the mass stopping power and range of protons in biological human body tissues (ovary, lung and breast) were calculated at the energy ranging from 0.04 MeV to 200 MeV using the MATLAB Program. The data relating to the densities, average atomic number to mass number and excitation energy for the present tissues were collected from ICRU Report 46. The mass stopping power was calculated by the Bethe formula. Moreover, the simple integration (continuous slowing down approximation) method was employed for calculating protons range at the tissues. The results of the mass stopping power versus energy and the range versus energy were presented graphically and the empirical formulae for calculating the mass stopping power and the ranges were obtained. The present results for mass stopping powers and ranges were compared with the results obtained by others. Good agreements were found between them, especially at the energy ranging from 3 to 200 MeV.
文摘In this paper we consider the problem of determining the optimal time to buy an asset in a position of an uptrend or downtrend in the financial market and currency market as well as other markets. Asset price is modeled as a geometric Brownian motion with drift being a two-state Markov chain. Based on observations of asset prices, investors want to detect the change points of price trends as accurately as possible, so that they can make the decision to buy. Using filtering techniques and stochastic analysis, we will develop the optimal boundary at which investors implement their decisions when the posterior probability process reaches a certain threshold.
基金Supported by the National Natural Science Foundation Of China under Grant Nos 11265013,11175074,11264033 and 11464040
文摘The dissipation phenomenon in the heavy-ion reaction at incident energy near the Fermi energy is studied by simulating the reaction ^129Xe+^129Sn with the isospin-dependent quantum molecular dynamics model. The calculations involving a proper prescription of implementing the Pauli exclusion principle show that the isotropy ratio measured by free protons emitted in the reaction at energy slightly higher than the Fermi energy is in agreement with the experimental data recently released by the INDRA collaboration. A feasible value of the Pauli-blocking factor is estimated by comparing the theoretical results with the experimental data for the energy range considered here.
文摘With the method of Rutherford backscattering of heavy ions from heavy substrate, the stopping powers of 11B, 12C and 19F in silver film were measured at energies from 0.11-0.53 MeV / u. The results are compared with the previous experimental data and the semiempirical calculations of TRIM-90.
基金Supported by the National Natural Science Foundation of China(11771286,11371317)the Zhejiang Provincial Natural Science Foundation of China(LQ18A010007)
文摘Suppose that C is a finite collection of patterns. Observe a Markov chain until one of the patterns in C occurs as a run. This time is denoted by τ. In this paper, we aim to give an easy way to calculate the mean waiting time E(τ) and the stopping probabilities P(τ = τA)with A ∈ C, where τA is the waiting time until the pattern A appears as a run.