Long-term storage of crop seeds is critical for the conservation of germplasm resources, ensuring food supply, and supporting sustainable production. Rice, as a major food staple, has a substantial stock for consumpti...Long-term storage of crop seeds is critical for the conservation of germplasm resources, ensuring food supply, and supporting sustainable production. Rice, as a major food staple, has a substantial stock for consumption and production worldwide. However, its food value and seed viability tend to decline during storage. Understanding the physiological responses and molecular mechanisms of aging tolerance forms the basis for enhancing seed storability in rice. This review outlines the latest progress in influential factors, evaluation methods, and identification indices of seed storability. It also discusses the physiological consequences, molecular mechanisms, and strategies for breeding aging-tolerant rice in detail. Finally, it highlights challenges in seed storability research that require future attention. This review offers a theoretical foundation and research direction for uncovering the mechanisms behind seed storability and breeding aging-tolerant rice.展开更多
对某双幅钢箱梁连续梁桥涡激振动进行风洞试验和数值模拟研究。基于二次开发UDF(user defined function)程序嵌入Fluent软件进行二维流固耦合分析,模拟了双幅桥梁断面的涡激振动;通过对比节段模型风洞试验及数值模拟结果,验证了数值模...对某双幅钢箱梁连续梁桥涡激振动进行风洞试验和数值模拟研究。基于二次开发UDF(user defined function)程序嵌入Fluent软件进行二维流固耦合分析,模拟了双幅桥梁断面的涡激振动;通过对比节段模型风洞试验及数值模拟结果,验证了数值模拟方法的可靠性,并从流场的角度直观分析双幅钢箱梁断面涡激振动机理。研究结果表明:上游幅主梁断面下表面的主涡与其背风侧的正压区的周期性变化诱发了上游幅主梁断面的竖向涡激振动;下游幅主梁断面上、下表面的旋涡交替作用于主梁断面并脱落,形成了周期性的作用,导致了下游幅主梁断面的竖向涡激共振;下游幅主梁断面上、下表面的旋涡分别在迎风侧栏杆与上游幅箱梁尾部、下游幅箱梁前端得到增强,导致了下游幅主梁断面的涡激振动的振幅大于上游幅主梁断面。研究结果为双幅桥梁或双钝体断面的涡激振动研究提供参考经验。展开更多
为提高双幅钢箱梁涡激振动性能,以某三跨钢箱连续梁桥为研究背景,提出了基于主动吸气控制的双幅钢箱梁涡激振动抑制措施。采用计算流体动力学方法研究了主动吸气控制措施对双幅钢箱梁涡激振动的抑制效果。结合Fluent用户自定义函数(user...为提高双幅钢箱梁涡激振动性能,以某三跨钢箱连续梁桥为研究背景,提出了基于主动吸气控制的双幅钢箱梁涡激振动抑制措施。采用计算流体动力学方法研究了主动吸气控制措施对双幅钢箱梁涡激振动的抑制效果。结合Fluent用户自定义函数(user defined function,UDF)和“动网格”技术,计算了双幅钢箱梁的涡激振动响应。通过对比风洞试验和数值模拟计算结果,验证了数值模拟方法的可靠性。从能量输入机制、流场等角度分析了主动吸气控制措施的抑振机理。研究结果表明,主动吸气控制措施能有效抑制双幅钢箱梁的涡激振动。吸气源的布置及吸气气流速率的大小均会影响对涡激振动的控制效果。吸气气流与回流相互作用,从而有效地抑制了桥梁的涡激振动。展开更多
基金funded by the Postgraduate Scientific Research Innovative Project of Hunan Province, China (Grant No. QL20220107)the Science and Technology Innovation Program of Hunan Province, China (Grant Nos. 2021RC4066 and 2023NK1010)the Special Funds for the Construction of Innovative Provinces in Hunan Province, China (Grant No. 2021NK1012)。
文摘Long-term storage of crop seeds is critical for the conservation of germplasm resources, ensuring food supply, and supporting sustainable production. Rice, as a major food staple, has a substantial stock for consumption and production worldwide. However, its food value and seed viability tend to decline during storage. Understanding the physiological responses and molecular mechanisms of aging tolerance forms the basis for enhancing seed storability in rice. This review outlines the latest progress in influential factors, evaluation methods, and identification indices of seed storability. It also discusses the physiological consequences, molecular mechanisms, and strategies for breeding aging-tolerant rice in detail. Finally, it highlights challenges in seed storability research that require future attention. This review offers a theoretical foundation and research direction for uncovering the mechanisms behind seed storability and breeding aging-tolerant rice.
文摘对某双幅钢箱梁连续梁桥涡激振动进行风洞试验和数值模拟研究。基于二次开发UDF(user defined function)程序嵌入Fluent软件进行二维流固耦合分析,模拟了双幅桥梁断面的涡激振动;通过对比节段模型风洞试验及数值模拟结果,验证了数值模拟方法的可靠性,并从流场的角度直观分析双幅钢箱梁断面涡激振动机理。研究结果表明:上游幅主梁断面下表面的主涡与其背风侧的正压区的周期性变化诱发了上游幅主梁断面的竖向涡激振动;下游幅主梁断面上、下表面的旋涡交替作用于主梁断面并脱落,形成了周期性的作用,导致了下游幅主梁断面的竖向涡激共振;下游幅主梁断面上、下表面的旋涡分别在迎风侧栏杆与上游幅箱梁尾部、下游幅箱梁前端得到增强,导致了下游幅主梁断面的涡激振动的振幅大于上游幅主梁断面。研究结果为双幅桥梁或双钝体断面的涡激振动研究提供参考经验。
文摘为提高双幅钢箱梁涡激振动性能,以某三跨钢箱连续梁桥为研究背景,提出了基于主动吸气控制的双幅钢箱梁涡激振动抑制措施。采用计算流体动力学方法研究了主动吸气控制措施对双幅钢箱梁涡激振动的抑制效果。结合Fluent用户自定义函数(user defined function,UDF)和“动网格”技术,计算了双幅钢箱梁的涡激振动响应。通过对比风洞试验和数值模拟计算结果,验证了数值模拟方法的可靠性。从能量输入机制、流场等角度分析了主动吸气控制措施的抑振机理。研究结果表明,主动吸气控制措施能有效抑制双幅钢箱梁的涡激振动。吸气源的布置及吸气气流速率的大小均会影响对涡激振动的控制效果。吸气气流与回流相互作用,从而有效地抑制了桥梁的涡激振动。
