The spatial structure and variation of the upwelling in the waters east and northeast of Hainan Island, China during 2000-2007 were investigated using a nested high-resolution Princeton Ocean Model (POM) forced by Qui...The spatial structure and variation of the upwelling in the waters east and northeast of Hainan Island, China during 2000-2007 were investigated using a nested high-resolution Princeton Ocean Model (POM) forced by QuikSCAT winds. The model produced good simulations of the summer upwelling and the seasonal and annual variability. Strong upwelling occurs from mid-July to mid-August with a peak east of Hainan Island associated with the southwesterly monsoon in the South China Sea. Sensitivity experiments indicated that when the local wind stress controls the variability of the upwelling, the large-scale circulation significantly enhances the upwelling northeast of Hainan Island by inducing a local upwelling and transporting cold water northeast-ward along the island's east coast. The joint effects of the local wind stress and large-scale circulation result in stronger upwelling northeast of Hainan Island. This implies that the annual variation of the upwelling northeast of Hainan Island is controlled not only by the local alongshore wind stress but also by the large-scale circulation. This result will help us investigate the decadal variation of the upwelling in this region in the future.展开更多
A new quenching process using the cold pyrolysis gas has been proposed for the partial oxidation(POX) of methane to recover the heat. The mixing of hot product gas and cold pyrolysis gas in milliseconds is critical to...A new quenching process using the cold pyrolysis gas has been proposed for the partial oxidation(POX) of methane to recover the heat. The mixing of hot product gas and cold pyrolysis gas in milliseconds is critical to this new approach. Two most widely-used rapid mixing configurations, i.e. the jet-in-cross-flow(JICF) and impinging flow configurations, are compared in terms of mixing and quenching performances using computational fluid dynamics(CFD) coupled with detailed reaction mechanism Leeds 1.5. The mixedness, residence time distribution, temperature decreasing rate and loss ratio of acetylene during the quenching are systematically studied. The results show that the impinging flow has a more uniform mixing and narrower residence time distribution than the JICF.However, the temperature decreasing rate of the mainstream is faster in the JICF than in the impinging flow. The loss ratio of acetylene in the quenching process is 2.89% for the JICF and 1.45% for the impinging flow, showing that the impinging flow configuration is better and feasible for the quenching of POX of methane.展开更多
In this paper, the initial boundary value problem of semilinear degenerate reaction-diffusion systems is studied. The regularization method and upper and lower solutions technique are employed to show the existence an...In this paper, the initial boundary value problem of semilinear degenerate reaction-diffusion systems is studied. The regularization method and upper and lower solutions technique are employed to show the existence and continuation of a positive classical solution. The location of quenching points is found. The critical length is estimated by the eigenvalue method.展开更多
Based on the fluid transient theory and explosive dynamics, a new type explosive driven jet is put forward. The generator of the proposed jet system comprises an explosive power source, a dynamic cavity, a spacing blo...Based on the fluid transient theory and explosive dynamics, a new type explosive driven jet is put forward. The generator of the proposed jet system comprises an explosive power source, a dynamic cavity, a spacing block, a water storage chamber, and a rubber membrane. The dynamic explosive source of power for the jet is composed of a cartridge and a bullet. The pressure in the dynamic cavity goes up to a range from 300 MPa to 350 MPa very quickly when the bullet is emitted. Driven by such a high pressure, the speed of the jet reaches 120 m/s. The effective distance to distinguish a fire is within 40 m. The jet has the following advantages over a conventional high-pressure water jet system: 1)strong power and strong transient force produced by dynamic source; 2) the energy of the dynamical source concentrated in a small scope with very little loss; 3) extensive applicability; and 4) safe usage without sparkling and smoke.展开更多
A new spinning method to manufacture the cylindrical parts with nano/ultrafine grained structures is proposed, which consists of quenching, power spinning and recrystallization annealing. The microstructural evolution...A new spinning method to manufacture the cylindrical parts with nano/ultrafine grained structures is proposed, which consists of quenching, power spinning and recrystallization annealing. The microstructural evolution during the different process stages and macroforming quality of the spun parts made of ASTM 1020 steel are investigated. The results show that the microstructures of the ferrites and pearlites in the ASTM 1020 steel are transformed to the lath martensites after quenching. The martensite laths obtained by quenching are refined to 87 nm and a small amount of nanoscale deformation twins with an average thickness of 20 nm is generated after performing a 3-pass stagger spinning with 55% thinning ratio of wall thickness, where the equivalent strain required is only 0.92. The equiaxial ferritic grains with an average size of 160 nm and nano-carbides are generated by subsequent recrystallization annealing at 480°C for 30 min. The spun parts with high dimensional precision and low surface roughness are obtained by the forming method developed in this work, combining quenching with 3-pass stagger spinning and recrystallization annealing.展开更多
The development of heat recovery methods for dry granulation processes from blast furnace slag in the iron and steel industry is limited because of the high consumption of granulation energy during these processes.To ...The development of heat recovery methods for dry granulation processes from blast furnace slag in the iron and steel industry is limited because of the high consumption of granulation energy during these processes.To determine the factors that influence the diameter of granulated particles,a paraffin test platform for gas quenching granulation was established.The influences of air velocity,air flow rate,liquid mass flow rate,and liquid pipe diameter on the final particle size and mass distribution were studied.Experimental results showed that the final particle size decreased(from 1.07 mm to 0.81 mm) with increasing air velocity(from 28.3 m/s to 113.2 m/s).However,when air velocity was higher than 60 m/s,its influence on particle diameter decreased significantly.The experimental data were analyzed using SPSS Statistics software,which indicated that the effect of air velocity on particle diameter was the most significant,followed by those of air flow and liquid pipe diameter.The effect of liquid mass flow was the least significant.展开更多
A quantum simulator is proposed for nucleation and growth dynamics using an out-of equilibrium optical lattice. We calculate the density of neutral atoms in the lattice and we establish the connection with the Kolmogo...A quantum simulator is proposed for nucleation and growth dynamics using an out-of equilibrium optical lattice. We calculate the density of neutral atoms in the lattice and we establish the connection with the KolmogorovMehl-Johnson-Avrami model. Here we show that an Avrami equation can describe most of the evolution in time of the population growth in the lattice, coherence between neutral atoms leads a complex growth rate.展开更多
Experiments were conducted to investigate the cooling manner of an ultra-thick hot aluminum alloy plate during multistage quenching. Cooling curves and heat flux curves of different rapid quenching flux varied from 23...Experiments were conducted to investigate the cooling manner of an ultra-thick hot aluminum alloy plate during multistage quenching. Cooling curves and heat flux curves of different rapid quenching flux varied from 23 to 40 L min-1 and were analyzed in detail. In this investigation, cooling process was divided into the following four steps： （Ⅰ） starting step, （Ⅱ） rapid cooling step, （Ⅲ） slow cooling step, and （Ⅳ） stopping step. Based on the curves, the calculation method for surface transfer coefficient was provided, and the effects of coefficient on surface temperature and quenching flux were discussed. Results showed that the transfer coefficient disagreed with heat flux and that it is a nonlinear function of surface temperature. The highest coefficient was observed not in the rapid cooling step with the largest heat flux but in the slow cooling step with lower heat flux. The coefficient increased with surface temperature ranging from 480 to 150℃, and a coefficient peak appeared in the temperature range of 150- 100℃. The coefficient also increased with quenching flux. Finally, a simulation was performed using the finite element method to verify the reliability of the coefficient results, which showed good agreement with the measurement values.展开更多
基金Supported by the Knowledge Innovation Program of Chinese Academy of Sciences (Nos. KZCX2-YW-Q11-02, KZCX2-EW-208)the One Hundred Talent Program of Chinese Academy of Sciences+1 种基金the National Natural Science Foundation of China (No. 41076009)the Youth Frontier Science Project of the South China Sea Institute of Oceanology(No. SQ200914)
文摘The spatial structure and variation of the upwelling in the waters east and northeast of Hainan Island, China during 2000-2007 were investigated using a nested high-resolution Princeton Ocean Model (POM) forced by QuikSCAT winds. The model produced good simulations of the summer upwelling and the seasonal and annual variability. Strong upwelling occurs from mid-July to mid-August with a peak east of Hainan Island associated with the southwesterly monsoon in the South China Sea. Sensitivity experiments indicated that when the local wind stress controls the variability of the upwelling, the large-scale circulation significantly enhances the upwelling northeast of Hainan Island by inducing a local upwelling and transporting cold water northeast-ward along the island's east coast. The joint effects of the local wind stress and large-scale circulation result in stronger upwelling northeast of Hainan Island. This implies that the annual variation of the upwelling northeast of Hainan Island is controlled not only by the local alongshore wind stress but also by the large-scale circulation. This result will help us investigate the decadal variation of the upwelling in this region in the future.
基金Supported by the National Natural Science Foundation of China(21276135)the Project of Chinese Ministry of Education(113004A)
文摘A new quenching process using the cold pyrolysis gas has been proposed for the partial oxidation(POX) of methane to recover the heat. The mixing of hot product gas and cold pyrolysis gas in milliseconds is critical to this new approach. Two most widely-used rapid mixing configurations, i.e. the jet-in-cross-flow(JICF) and impinging flow configurations, are compared in terms of mixing and quenching performances using computational fluid dynamics(CFD) coupled with detailed reaction mechanism Leeds 1.5. The mixedness, residence time distribution, temperature decreasing rate and loss ratio of acetylene during the quenching are systematically studied. The results show that the impinging flow has a more uniform mixing and narrower residence time distribution than the JICF.However, the temperature decreasing rate of the mainstream is faster in the JICF than in the impinging flow. The loss ratio of acetylene in the quenching process is 2.89% for the JICF and 1.45% for the impinging flow, showing that the impinging flow configuration is better and feasible for the quenching of POX of methane.
文摘In this paper, the initial boundary value problem of semilinear degenerate reaction-diffusion systems is studied. The regularization method and upper and lower solutions technique are employed to show the existence and continuation of a positive classical solution. The location of quenching points is found. The critical length is estimated by the eigenvalue method.
基金the national Natural Science Foundation of China (No. 59874033).
文摘Based on the fluid transient theory and explosive dynamics, a new type explosive driven jet is put forward. The generator of the proposed jet system comprises an explosive power source, a dynamic cavity, a spacing block, a water storage chamber, and a rubber membrane. The dynamic explosive source of power for the jet is composed of a cartridge and a bullet. The pressure in the dynamic cavity goes up to a range from 300 MPa to 350 MPa very quickly when the bullet is emitted. Driven by such a high pressure, the speed of the jet reaches 120 m/s. The effective distance to distinguish a fire is within 40 m. The jet has the following advantages over a conventional high-pressure water jet system: 1)strong power and strong transient force produced by dynamic source; 2) the energy of the dynamical source concentrated in a small scope with very little loss; 3) extensive applicability; and 4) safe usage without sparkling and smoke.
基金supported by National Natural Science Foundation of China(Grant No.51075153)Natural Science Foundation of Guangdong Province(Grant No.10151040301000000)+1 种基金Key Laboratory of Precision Equipment and Manufacturing Technology of Guangdong Province(Grant No.PEMT1202)the EU FP7 Marie Curie International Research Staff Exchange Scheme(IRSES)Mat Pro Future Project(Grant No.318968)
文摘A new spinning method to manufacture the cylindrical parts with nano/ultrafine grained structures is proposed, which consists of quenching, power spinning and recrystallization annealing. The microstructural evolution during the different process stages and macroforming quality of the spun parts made of ASTM 1020 steel are investigated. The results show that the microstructures of the ferrites and pearlites in the ASTM 1020 steel are transformed to the lath martensites after quenching. The martensite laths obtained by quenching are refined to 87 nm and a small amount of nanoscale deformation twins with an average thickness of 20 nm is generated after performing a 3-pass stagger spinning with 55% thinning ratio of wall thickness, where the equivalent strain required is only 0.92. The equiaxial ferritic grains with an average size of 160 nm and nano-carbides are generated by subsequent recrystallization annealing at 480°C for 30 min. The spun parts with high dimensional precision and low surface roughness are obtained by the forming method developed in this work, combining quenching with 3-pass stagger spinning and recrystallization annealing.
基金supported by the National Natural Science Foundation of China(Grant No.51206010)the National Basic Research Program of China(973 Program)(Grant No.2012CB720406)
文摘The development of heat recovery methods for dry granulation processes from blast furnace slag in the iron and steel industry is limited because of the high consumption of granulation energy during these processes.To determine the factors that influence the diameter of granulated particles,a paraffin test platform for gas quenching granulation was established.The influences of air velocity,air flow rate,liquid mass flow rate,and liquid pipe diameter on the final particle size and mass distribution were studied.Experimental results showed that the final particle size decreased(from 1.07 mm to 0.81 mm) with increasing air velocity(from 28.3 m/s to 113.2 m/s).However,when air velocity was higher than 60 m/s,its influence on particle diameter decreased significantly.The experimental data were analyzed using SPSS Statistics software,which indicated that the effect of air velocity on particle diameter was the most significant,followed by those of air flow and liquid pipe diameter.The effect of liquid mass flow was the least significant.
基金Supported by Universidad Santiago de Cali Project No.935-621115-N23Conciencias Project Nos.123365842816,FP44842-014-2015
文摘A quantum simulator is proposed for nucleation and growth dynamics using an out-of equilibrium optical lattice. We calculate the density of neutral atoms in the lattice and we establish the connection with the KolmogorovMehl-Johnson-Avrami model. Here we show that an Avrami equation can describe most of the evolution in time of the population growth in the lattice, coherence between neutral atoms leads a complex growth rate.
基金supported by the National Basic Research Program of China(Grant No.2012CB619500)the Major State Research Program of China(Grant No.2016YFB0300901)+1 种基金the National Natural Science Foundation of China(Grant No.51375503)the BaGui Scholars Program of China’s Guangxi Zhuang Autonomous Region(Grant No.2013A017)
文摘Experiments were conducted to investigate the cooling manner of an ultra-thick hot aluminum alloy plate during multistage quenching. Cooling curves and heat flux curves of different rapid quenching flux varied from 23 to 40 L min-1 and were analyzed in detail. In this investigation, cooling process was divided into the following four steps： （Ⅰ） starting step, （Ⅱ） rapid cooling step, （Ⅲ） slow cooling step, and （Ⅳ） stopping step. Based on the curves, the calculation method for surface transfer coefficient was provided, and the effects of coefficient on surface temperature and quenching flux were discussed. Results showed that the transfer coefficient disagreed with heat flux and that it is a nonlinear function of surface temperature. The highest coefficient was observed not in the rapid cooling step with the largest heat flux but in the slow cooling step with lower heat flux. The coefficient increased with surface temperature ranging from 480 to 150℃, and a coefficient peak appeared in the temperature range of 150- 100℃. The coefficient also increased with quenching flux. Finally, a simulation was performed using the finite element method to verify the reliability of the coefficient results, which showed good agreement with the measurement values.
