In this paper, the influence depths of all levels of wind power produced waves are reckoned according to the measured swaying degree when a submarine meets with a force 11 strong tropical storm and has to submerge; Th...In this paper, the influence depths of all levels of wind power produced waves are reckoned according to the measured swaying degree when a submarine meets with a force 11 strong tropical storm and has to submerge; Then the minimum submergence depth is given when a submarine is faced with weather systems with force ≥ 6 wind and the swaying degree of less than 12 degree is assured as reference for a submarine working and sailing in big strong winds and waves.展开更多
A class of one-way isothermal mass transfer processes with Fick’s diffusive mass transfer law[g ∝Δ(c)]is investigated in this paper.Based on the definition of the mass entransy,the entransy dissipation function whi...A class of one-way isothermal mass transfer processes with Fick’s diffusive mass transfer law[g ∝Δ(c)]is investigated in this paper.Based on the definition of the mass entransy,the entransy dissipation function which reflects the irreversibility of mass transfer ability loss is derived.The optimal concentration allocations of the key components corresponding to the highand low-concentration sides for the minimum entransy dissipation of the mass transfer process are obtained by applying opti- mal control theory and compared with the strategies of the minimum entropy generation,constant mass transfer flux(constant concentration difference),and constant concentration ratio(constant chemical potential difference).The results are as follows. For the optimal mass transfer strategy of the minimum entransy dissipation,the product of the square of the key component concentration difference between the high-and the low-concentration sides and the inert component concentration at the low-concentration side is a constant,while for that of the minimum entropy generation,the ratio of the square of the key com-ponent concentration difference between the high-and the low-concentration sides to the key component concentration at the low-concentration side is a constant;when the mass transfer process is not involved in energy conversion process,the optimi-zation principle should be the minimum entransy dissipation;the mass transfer strategy of constant concentration difference is superior to that of constant concentration ratio.The results obtained in this paper can provide some theoretical guidelines for optimal designs and operations of practical mass transfer processes.展开更多
To reduce the fuel consumption of internal combustion engines, more attention has been paid to the tribological performance of the piston ring pack during the cold start and idle operations. In this research, a numeri...To reduce the fuel consumption of internal combustion engines, more attention has been paid to the tribological performance of the piston ring pack during the cold start and idle operations. In this research, a numerical model considering the cylinder liner deformation and the piston ring conformability is developed to predict the blow-by, lubrication, friction and wear of the piston ring pack under different operating conditions. The gas flow rate, inter-ring gas pressures, minimum oil film thickness, frictional force and wear load during cold start are calculated and compared with those during warm idle operating conditions. The results show that cylinder liner deformation and piston ring conformability together obviously affect blow-by and other tribological performance. Meanwhile, it is found that friction loss is larger during cold start than during warm idle operating conditions. However, the wear process is more severe during warm idle operation than during cold start. From this research, the blow-by and tribological performance of the piston ring pack during cold start and warm idle operations are understood more deeply.展开更多
From the inspection of noncommutative quantum mechanics, we obtain an approximate equivalent relation for the energy dependence of the Planck constant in the noncommutative space, which means a minimal length of the s...From the inspection of noncommutative quantum mechanics, we obtain an approximate equivalent relation for the energy dependence of the Planck constant in the noncommutative space, which means a minimal length of the space. We find that this relation is reasonable and it can inherit the main properties of the noncommutative space.Based on this relation, we derive the modified Klein–Gordon equation and Dirac equation. We investigate the scalar field and φ4model and then quantum electrodynamics in our theory, and derive the corresponding Feynman rules. These results may be considered as reasonable approximations to those of noncommutative quantum field theory. Our theory also shows a connection between the space with a minimal length and the noncommutative space.展开更多
In this paper the variation of interface stress intensity factors is considered under arbitrary material combinations for several problems such as central internal interface cracks, periodic interface cracks, and edge...In this paper the variation of interface stress intensity factors is considered under arbitrary material combinations for several problems such as central internal interface cracks, periodic interface cracks, and edge interface cracks. The stress intensity factors for all these problems have been determined in terms of Dundurs＇ parameters a, b by the application of FEM in the authors＇ previous papers. In this paper, the variations of the stress intensity factors for all these problems are discussed under arbitrary a, b, then the maximum and minimum values of dimensionless stress intensity factors FI,max, FII,max, FI,min, FII,max are indicated on the map of a, b. As an example, it is found that FI,max always appears when （a, b）= （0.2,0.3）, and FI,min always appears when （a, b）= （1,0）, for the central internal interface cracks independent of crack length.展开更多
文摘In this paper, the influence depths of all levels of wind power produced waves are reckoned according to the measured swaying degree when a submarine meets with a force 11 strong tropical storm and has to submerge; Then the minimum submergence depth is given when a submarine is faced with weather systems with force ≥ 6 wind and the swaying degree of less than 12 degree is assured as reference for a submarine working and sailing in big strong winds and waves.
基金supported by the National Natural Science Foundation of China(Grant No.10905093)the Program for New Century Excellent Talents in University of China(Grant No.NCET-04-1006)the Foun-dation for the Author of National Excellent Doctoral Dissertation of China(Grant No.200136)
文摘A class of one-way isothermal mass transfer processes with Fick’s diffusive mass transfer law[g ∝Δ(c)]is investigated in this paper.Based on the definition of the mass entransy,the entransy dissipation function which reflects the irreversibility of mass transfer ability loss is derived.The optimal concentration allocations of the key components corresponding to the highand low-concentration sides for the minimum entransy dissipation of the mass transfer process are obtained by applying opti- mal control theory and compared with the strategies of the minimum entropy generation,constant mass transfer flux(constant concentration difference),and constant concentration ratio(constant chemical potential difference).The results are as follows. For the optimal mass transfer strategy of the minimum entransy dissipation,the product of the square of the key component concentration difference between the high-and the low-concentration sides and the inert component concentration at the low-concentration side is a constant,while for that of the minimum entropy generation,the ratio of the square of the key com-ponent concentration difference between the high-and the low-concentration sides to the key component concentration at the low-concentration side is a constant;when the mass transfer process is not involved in energy conversion process,the optimi-zation principle should be the minimum entransy dissipation;the mass transfer strategy of constant concentration difference is superior to that of constant concentration ratio.The results obtained in this paper can provide some theoretical guidelines for optimal designs and operations of practical mass transfer processes.
基金supported by the National Natural Science Foundation of China(Grant No.51375300)the Research Project of State Key Laboratory of Mechanical System and Vibration(Grant No.MSVZD201401)
文摘To reduce the fuel consumption of internal combustion engines, more attention has been paid to the tribological performance of the piston ring pack during the cold start and idle operations. In this research, a numerical model considering the cylinder liner deformation and the piston ring conformability is developed to predict the blow-by, lubrication, friction and wear of the piston ring pack under different operating conditions. The gas flow rate, inter-ring gas pressures, minimum oil film thickness, frictional force and wear load during cold start are calculated and compared with those during warm idle operating conditions. The results show that cylinder liner deformation and piston ring conformability together obviously affect blow-by and other tribological performance. Meanwhile, it is found that friction loss is larger during cold start than during warm idle operating conditions. However, the wear process is more severe during warm idle operation than during cold start. From this research, the blow-by and tribological performance of the piston ring pack during cold start and warm idle operations are understood more deeply.
基金Supported by the Fundamental Research Funds for the Central Universities under Grant No.2013ZM0109
文摘From the inspection of noncommutative quantum mechanics, we obtain an approximate equivalent relation for the energy dependence of the Planck constant in the noncommutative space, which means a minimal length of the space. We find that this relation is reasonable and it can inherit the main properties of the noncommutative space.Based on this relation, we derive the modified Klein–Gordon equation and Dirac equation. We investigate the scalar field and φ4model and then quantum electrodynamics in our theory, and derive the corresponding Feynman rules. These results may be considered as reasonable approximations to those of noncommutative quantum field theory. Our theory also shows a connection between the space with a minimal length and the noncommutative space.
基金supported by the Japanese Government (Monbukagukusho) Scholarshipthe National Basic Research Program of China (Grant No.2011CB013702)
文摘In this paper the variation of interface stress intensity factors is considered under arbitrary material combinations for several problems such as central internal interface cracks, periodic interface cracks, and edge interface cracks. The stress intensity factors for all these problems have been determined in terms of Dundurs＇ parameters a, b by the application of FEM in the authors＇ previous papers. In this paper, the variations of the stress intensity factors for all these problems are discussed under arbitrary a, b, then the maximum and minimum values of dimensionless stress intensity factors FI,max, FII,max, FI,min, FII,max are indicated on the map of a, b. As an example, it is found that FI,max always appears when （a, b）= （0.2,0.3）, and FI,min always appears when （a, b）= （1,0）, for the central internal interface cracks independent of crack length.
