Two mutants with rolled leaves, temporally designated as rl3(t)-I and rl3(t)-2, were served for exploring the mechanism underlying the rolled leaf characteristic. Except for having typical rolled leaves, the plant...Two mutants with rolled leaves, temporally designated as rl3(t)-I and rl3(t)-2, were served for exploring the mechanism underlying the rolled leaf characteristic. Except for having typical rolled leaves, the plant heights and panicle lengths of rl3(t)-1 and rl3(t)-2 significantly decreased, and the seed-setting rate also decreased when compared with wild type 93-11. Cytological analysis suggested that the rolled leaf phenotype might be caused by the changes of number and size of bulliform cells. Genetic analysis indicated rl3(t)-1 is allelic to rl3(t)-2, and controlled by a recessive gene. Gene mapping result indicated that RL3(t) gene resided in a 46-kb long region governed by the sequence tag site markers S3-39 and S3-36 on rice chromosome 3. The result provides an important clue for further cloning the RL3(t) and understanding the mechanism of rice leaf development.展开更多
The curved martensite structures have been observed in CuZnAI-based shape memory alloys by both transmission electron microscope and optical microscope. It was found that the curved martensite structures observed in a...The curved martensite structures have been observed in CuZnAI-based shape memory alloys by both transmission electron microscope and optical microscope. It was found that the curved martensite structures observed in as-solution treated, as-aged and as-trained alloys usually occurred around dislocation tangles or precipitate, at the plate boundary or grain boundary, and when the growing plates collided with each other or alternate mutually.展开更多
Lath-shaped and highly crystalline trioctahedral smectites were synthesized under hydrothermal conditions. The quenched glasses with stoichiometrically dehydrated Na-smectite compositions were treated at (a) 500℃ a...Lath-shaped and highly crystalline trioctahedral smectites were synthesized under hydrothermal conditions. The quenched glasses with stoichiometrically dehydrated Na-smectite compositions were treated at (a) 500℃ and 100 MPa for 1 and 11 days; and (b) 300℃ and 100 MPa for 7 days. The crystallinity and particle size of products were dependent on the chemical composition of the starting glass, synthetic temperature and duration of hydrothermal treatment. The high structural ordering and large dimensions of the products were confirmed from the sharpness of XRD peaks; and hydration behavior under controlled relative humidity. Transmission electron microscopy was also performed for the characterization of the particle size of product. Particle sizes vary from ca. 10 nm to a few pm by changing the chemical compositions of the starting materials. The product with the highest structural ordering and largest dimension was obtained from Nao.33(Mg1.83Al0.67)Si4O11 glass treated at 500℃ and 100 MPa for 1 day. The obtained results also confirmed the metastability and compositional dependency in the formation of highly crystalline trioctahedral smectite at hydrothermal conditions.展开更多
The use of a shaped liner driven by electromagnetic force is a new means of forming jets. To study the mechanism of jet formation driven by electromagnetic force, we considered the current skin effect and the characte...The use of a shaped liner driven by electromagnetic force is a new means of forming jets. To study the mechanism of jet formation driven by electromagnetic force, we considered the current skin effect and the characteristics of electromagnetic loading and established a coupling model of "ElectriceMagnetic eForce" and the theoretical model of jet formation under electromagnetic force. The jet formation and penetration of conical and trumpet liners have been calculated. Then, a numerical simulation of liner collapse under electromagnetic force, jet generation, and the stretching motion were performed using an ANSYS multiphysics processor. The calculated jet velocity, jet shape, and depth of penetration were consistent with the experimental results, with a relative error of less than 10%. In addition, we calculated the jet formation of different curvature trumpet liners driven by the same loading condition and obtained the influence rule of the curvature of the liner on jet formation. Results show that the theoretical model and the ANSYS multiphysics numerical method can effectively calculate the jet formation of liners driven by electromagnetic force, and in a certain range, the greater the curvature of the liner is, the greater the jet velocity is.展开更多
The bore-center annular shaped charge(BCASC)is a new type of shaped charge which can generate a larger-diameter hole in steel targets than classical shaped charges.In this paper,the influence of three liner materials,...The bore-center annular shaped charge(BCASC)is a new type of shaped charge which can generate a larger-diameter hole in steel targets than classical shaped charges.In this paper,the influence of three liner materials,i.e.molybdenum,nickel and copper,on BCASC formation and penetrating into steel targets was investigated by experiment and numerical simulation.The simulation results were well consistent with the experimental results.This study showed that,at 0.50D standoff distance,the axial velocity of the molybdenum projectile was lower than that of the nickel and copper projectiles.The nickel and copper projectiles had almost the same head velocity.The absolute values of the radial velocity of the molybdenum projectile head was lower than that of the nickel and copper projectiles.However,at 0.75D standoff distance,the absolute values of the radial velocity of the molybdenum projectile head became much greater than that of the nickel and copper projectile heads.The projectile formed by BCASC with the molybdenum liner had the highest penetration depth of 61.5 mm,which was 10.0%and 21.3%higher than that generated by the copper and nickel projectiles.展开更多
Overdriven detonation(ODD)in high explosives can be generated by Mach reflection of conical detonation waves propagating quasi-steadily in a co-axial double layer cylindrical charge.The inner core of the charge cons...Overdriven detonation(ODD)in high explosives can be generated by Mach reflection of conical detonation waves propagating quasi-steadily in a co-axial double layer cylindrical charge.The inner core of the charge consists of lower detonation velocity explosive with higher detonation velocity explosive for the outer core.The calculated pressures and detonation velocities in the ODD regime are compared with available results in the literature.The application of this technique to design a double layer shaped charge(DLSC)is numerically studied.It was discovered that the use of lower density-lower detonation velocity explosive in the inner core of DLSC can also yield similar results to those obtained with high density lower detonation velocity explosive.By analyzing previous experimental results and comparing with present simulations,it is demonstrated that ordinary shaped charges have some advantages over DLSC under certain conditions.展开更多
To ensure safe flight of multiple fixed-wing unmanned aerial vehicles(UAVs)formation,considering trajectory planning and formation control together,a leader trajectory planning method based on the sparse A*algorithm i...To ensure safe flight of multiple fixed-wing unmanned aerial vehicles(UAVs)formation,considering trajectory planning and formation control together,a leader trajectory planning method based on the sparse A*algorithm is introduced.Firstly,a formation controller based on prescribed performance theory is designed to control the transient and steady formation configuration,as well as the formation forming time,which not only can form the designated formation configuration but also can guarantee collision avoidance and terrain avoidance theoretically.Next,considering the constraints caused by formation controller on trajectory planning such as the safe distance,turn angle and step length,as well as the constraint of formation shape,a leader trajectory planning method based on sparse A^(*)algorithm is proposed.Simulation results show that the UAV formation can arrive at the destination safely with a short trajectory no matter keeping the formation or encountering formation transformation.展开更多
By using LS-DYNA simulation software,the influences of some structure parameters,such as top cone angle,wall thickness,liner height and height ratio of top cone,of double-angle liner on the jet formation were studied ...By using LS-DYNA simulation software,the influences of some structure parameters,such as top cone angle,wall thickness,liner height and height ratio of top cone,of double-angle liner on the jet formation were studied respectively.Their influences on jet tip velocity,tail velocity and penetration depth were revealed.The simulation results show that the formation is better if the top cone angle is selected as 28°,the wall is 2.6mm,the liner height is 140mm,and the height ratio of top cone is 60%.In large stand-off distance,the jet has a higher tip velocity,and the tip does not break.With the stand-off distance of 8 times of the charge diameter,the experiment penetrating steel target was carried out.The experiment and simulation results are in good agreement.展开更多
In the purpose of dealing with the inconsistency of the machine dimensions in cell formation and layout problems,comprehensively taking into account such factors as alternative process routings, lot splitting, cell in...In the purpose of dealing with the inconsistency of the machine dimensions in cell formation and layout problems,comprehensively taking into account such factors as alternative process routings, lot splitting, cell input and output( I / O)locations,an integrated cell formation and layout model considering unequal machine dimensions is established which aims at minimizing intra-cell material handling cost,inter-cell material handling cost and cell expansion cost. A sequence pair-based scatter search algorithm is proposed which simultaneously adopts the roulette wheel selection operator as a subsets combination method to improve the quality of new solutions and the dynamic reference sets updating method to accelerate the convergence rate. Through the comparison of the results achieved by the proposed algorithm, Lingo and simulated annealing under different problem scales,the correctness of the model and the effectiveness of the algorithm are verified.展开更多
四川盆地震旦系灯影组是重要的油气勘探开发层系,复杂的成岩演化和多期流体活动导致多种类型的白云岩形成。揭示震旦系白云岩的形成时代和成因不仅可以为四川盆地震旦系下一步的油气勘探提供更加充实的科学依据,也可为理解全球大规模存...四川盆地震旦系灯影组是重要的油气勘探开发层系,复杂的成岩演化和多期流体活动导致多种类型的白云岩形成。揭示震旦系白云岩的形成时代和成因不仅可以为四川盆地震旦系下一步的油气勘探提供更加充实的科学依据,也可为理解全球大规模存在前寒武纪白云岩的原因提供有益启示。本文针对川中地区震旦系灯影组“葡萄花边”白云岩的形成时代和成因进行了综合研究。岩相学研究表明,“葡萄花边”白云岩充填于藻白云岩的孔隙内,向内对称生长,结晶程度明显好于藻白云岩。在岩相学的基础上,利用激光剥蚀-电感耦合等离子体质谱(LA-ICP-MS)微区原位U-Pb定年确定其形成时代,研究结果表明:川中地区震旦系灯影组“葡萄花边”白云岩形成时代为530±12Ma~502±12Ma,略新于灯影组地层年代。结合微量元素分析以及碳-氧-锶同位素数据,对川中地区震旦系灯影组“葡萄花边”白云岩进行成因分析。结果表明,其稀土元素总量(∑REE)相对较低(0.680×10^(-6)~8.963×10^(-6)),δ13 C VPDB(-0.1‰~1.7‰)略低于与同时期海水沉积白云岩的碳同位素值,δ18 O VPDB(-2.3‰~1.4‰)略高于与同时期海水达到氧同位素平衡的白云岩氧同位素值,87 Sr/86 Sr值(0.70876~0.70909)基本落入同时期海水范围。稀土元素配分总体为水平的模式,所有样品表现出Ce负异常。表明其形成环境既非海水沉积环境,也不完全是表生大气水岩溶条件。综合上述特征,推断川中地区震旦系灯影组“葡萄花边”白云岩是在震旦纪末-寒武纪早期海平面高频低幅度波动这一背景下,灯影组地层多次暴露与淹没,形成岩溶裂缝和孔洞的同时在溶蚀空间内结晶形成。残留孔洞为其后流体活动、油气充注提供了储集空间。本研究为认识川中地区震旦系灯影组“葡萄花边”白云岩成因、震旦纪末-寒武纪早期水化学条件、及超深层油气勘探开发提供了有益参考。展开更多
基金financially supported by the National Natural Science Foundation of China (Grant No. 31171158)the Ministry of Science and Technology (Grant No. 2011ZX08009-003-005)+2 种基金the Natural Science Foundation of Jiangsu Province (Grant No. BK2012684)the Six Talent Peaks in Jiangsu Provincethe Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘Two mutants with rolled leaves, temporally designated as rl3(t)-I and rl3(t)-2, were served for exploring the mechanism underlying the rolled leaf characteristic. Except for having typical rolled leaves, the plant heights and panicle lengths of rl3(t)-1 and rl3(t)-2 significantly decreased, and the seed-setting rate also decreased when compared with wild type 93-11. Cytological analysis suggested that the rolled leaf phenotype might be caused by the changes of number and size of bulliform cells. Genetic analysis indicated rl3(t)-1 is allelic to rl3(t)-2, and controlled by a recessive gene. Gene mapping result indicated that RL3(t) gene resided in a 46-kb long region governed by the sequence tag site markers S3-39 and S3-36 on rice chromosome 3. The result provides an important clue for further cloning the RL3(t) and understanding the mechanism of rice leaf development.
基金Science Council of Shandong Province!under Grant No.89F0274
文摘The curved martensite structures have been observed in CuZnAI-based shape memory alloys by both transmission electron microscope and optical microscope. It was found that the curved martensite structures observed in as-solution treated, as-aged and as-trained alloys usually occurred around dislocation tangles or precipitate, at the plate boundary or grain boundary, and when the growing plates collided with each other or alternate mutually.
文摘Lath-shaped and highly crystalline trioctahedral smectites were synthesized under hydrothermal conditions. The quenched glasses with stoichiometrically dehydrated Na-smectite compositions were treated at (a) 500℃ and 100 MPa for 1 and 11 days; and (b) 300℃ and 100 MPa for 7 days. The crystallinity and particle size of products were dependent on the chemical composition of the starting glass, synthetic temperature and duration of hydrothermal treatment. The high structural ordering and large dimensions of the products were confirmed from the sharpness of XRD peaks; and hydration behavior under controlled relative humidity. Transmission electron microscopy was also performed for the characterization of the particle size of product. Particle sizes vary from ca. 10 nm to a few pm by changing the chemical compositions of the starting materials. The product with the highest structural ordering and largest dimension was obtained from Nao.33(Mg1.83Al0.67)Si4O11 glass treated at 500℃ and 100 MPa for 1 day. The obtained results also confirmed the metastability and compositional dependency in the formation of highly crystalline trioctahedral smectite at hydrothermal conditions.
基金supported by the Natural Science Funds for Distinguished Young Scholar (Grant No. 11602110)Jiangsu Province Graduate Research and Practice Innovation Program (No.KY CX180471)。
文摘The use of a shaped liner driven by electromagnetic force is a new means of forming jets. To study the mechanism of jet formation driven by electromagnetic force, we considered the current skin effect and the characteristics of electromagnetic loading and established a coupling model of "ElectriceMagnetic eForce" and the theoretical model of jet formation under electromagnetic force. The jet formation and penetration of conical and trumpet liners have been calculated. Then, a numerical simulation of liner collapse under electromagnetic force, jet generation, and the stretching motion were performed using an ANSYS multiphysics processor. The calculated jet velocity, jet shape, and depth of penetration were consistent with the experimental results, with a relative error of less than 10%. In addition, we calculated the jet formation of different curvature trumpet liners driven by the same loading condition and obtained the influence rule of the curvature of the liner on jet formation. Results show that the theoretical model and the ANSYS multiphysics numerical method can effectively calculate the jet formation of liners driven by electromagnetic force, and in a certain range, the greater the curvature of the liner is, the greater the jet velocity is.
基金supported by the National Natural Science Foundation of China(No.11732003)Beijing Natural Science Foundation(No.8182050)+1 种基金Science Challenge Project(No.TZ2016001)National Key R&D Program of China(No.2017YFC0804700)
文摘The bore-center annular shaped charge(BCASC)is a new type of shaped charge which can generate a larger-diameter hole in steel targets than classical shaped charges.In this paper,the influence of three liner materials,i.e.molybdenum,nickel and copper,on BCASC formation and penetrating into steel targets was investigated by experiment and numerical simulation.The simulation results were well consistent with the experimental results.This study showed that,at 0.50D standoff distance,the axial velocity of the molybdenum projectile was lower than that of the nickel and copper projectiles.The nickel and copper projectiles had almost the same head velocity.The absolute values of the radial velocity of the molybdenum projectile head was lower than that of the nickel and copper projectiles.However,at 0.75D standoff distance,the absolute values of the radial velocity of the molybdenum projectile head became much greater than that of the nickel and copper projectile heads.The projectile formed by BCASC with the molybdenum liner had the highest penetration depth of 61.5 mm,which was 10.0%and 21.3%higher than that generated by the copper and nickel projectiles.
基金Supported by the National Natural Science Foundation of China(11272059,11221202)Program for New Century Excellent Talents in University(NCET-12-0037)
文摘Overdriven detonation(ODD)in high explosives can be generated by Mach reflection of conical detonation waves propagating quasi-steadily in a co-axial double layer cylindrical charge.The inner core of the charge consists of lower detonation velocity explosive with higher detonation velocity explosive for the outer core.The calculated pressures and detonation velocities in the ODD regime are compared with available results in the literature.The application of this technique to design a double layer shaped charge(DLSC)is numerically studied.It was discovered that the use of lower density-lower detonation velocity explosive in the inner core of DLSC can also yield similar results to those obtained with high density lower detonation velocity explosive.By analyzing previous experimental results and comparing with present simulations,it is demonstrated that ordinary shaped charges have some advantages over DLSC under certain conditions.
基金supported by the National Natural Science Foundation of China(11502019).
文摘To ensure safe flight of multiple fixed-wing unmanned aerial vehicles(UAVs)formation,considering trajectory planning and formation control together,a leader trajectory planning method based on the sparse A*algorithm is introduced.Firstly,a formation controller based on prescribed performance theory is designed to control the transient and steady formation configuration,as well as the formation forming time,which not only can form the designated formation configuration but also can guarantee collision avoidance and terrain avoidance theoretically.Next,considering the constraints caused by formation controller on trajectory planning such as the safe distance,turn angle and step length,as well as the constraint of formation shape,a leader trajectory planning method based on sparse A^(*)algorithm is proposed.Simulation results show that the UAV formation can arrive at the destination safely with a short trajectory no matter keeping the formation or encountering formation transformation.
文摘By using LS-DYNA simulation software,the influences of some structure parameters,such as top cone angle,wall thickness,liner height and height ratio of top cone,of double-angle liner on the jet formation were studied respectively.Their influences on jet tip velocity,tail velocity and penetration depth were revealed.The simulation results show that the formation is better if the top cone angle is selected as 28°,the wall is 2.6mm,the liner height is 140mm,and the height ratio of top cone is 60%.In large stand-off distance,the jet has a higher tip velocity,and the tip does not break.With the stand-off distance of 8 times of the charge diameter,the experiment penetrating steel target was carried out.The experiment and simulation results are in good agreement.
基金Shanghai Municipal Natural Science Foundation,China(No.10ZR1431700)
文摘In the purpose of dealing with the inconsistency of the machine dimensions in cell formation and layout problems,comprehensively taking into account such factors as alternative process routings, lot splitting, cell input and output( I / O)locations,an integrated cell formation and layout model considering unequal machine dimensions is established which aims at minimizing intra-cell material handling cost,inter-cell material handling cost and cell expansion cost. A sequence pair-based scatter search algorithm is proposed which simultaneously adopts the roulette wheel selection operator as a subsets combination method to improve the quality of new solutions and the dynamic reference sets updating method to accelerate the convergence rate. Through the comparison of the results achieved by the proposed algorithm, Lingo and simulated annealing under different problem scales,the correctness of the model and the effectiveness of the algorithm are verified.
文摘四川盆地震旦系灯影组是重要的油气勘探开发层系,复杂的成岩演化和多期流体活动导致多种类型的白云岩形成。揭示震旦系白云岩的形成时代和成因不仅可以为四川盆地震旦系下一步的油气勘探提供更加充实的科学依据,也可为理解全球大规模存在前寒武纪白云岩的原因提供有益启示。本文针对川中地区震旦系灯影组“葡萄花边”白云岩的形成时代和成因进行了综合研究。岩相学研究表明,“葡萄花边”白云岩充填于藻白云岩的孔隙内,向内对称生长,结晶程度明显好于藻白云岩。在岩相学的基础上,利用激光剥蚀-电感耦合等离子体质谱(LA-ICP-MS)微区原位U-Pb定年确定其形成时代,研究结果表明:川中地区震旦系灯影组“葡萄花边”白云岩形成时代为530±12Ma~502±12Ma,略新于灯影组地层年代。结合微量元素分析以及碳-氧-锶同位素数据,对川中地区震旦系灯影组“葡萄花边”白云岩进行成因分析。结果表明,其稀土元素总量(∑REE)相对较低(0.680×10^(-6)~8.963×10^(-6)),δ13 C VPDB(-0.1‰~1.7‰)略低于与同时期海水沉积白云岩的碳同位素值,δ18 O VPDB(-2.3‰~1.4‰)略高于与同时期海水达到氧同位素平衡的白云岩氧同位素值,87 Sr/86 Sr值(0.70876~0.70909)基本落入同时期海水范围。稀土元素配分总体为水平的模式,所有样品表现出Ce负异常。表明其形成环境既非海水沉积环境,也不完全是表生大气水岩溶条件。综合上述特征,推断川中地区震旦系灯影组“葡萄花边”白云岩是在震旦纪末-寒武纪早期海平面高频低幅度波动这一背景下,灯影组地层多次暴露与淹没,形成岩溶裂缝和孔洞的同时在溶蚀空间内结晶形成。残留孔洞为其后流体活动、油气充注提供了储集空间。本研究为认识川中地区震旦系灯影组“葡萄花边”白云岩成因、震旦纪末-寒武纪早期水化学条件、及超深层油气勘探开发提供了有益参考。