激光雷达(light detection and ranging,LiDAR)作为一门新兴的主动遥感技术,近年来由于在提取和反演森林参数水平上不断提高,被越来越多地应用于动物生态学研究中。本文通过整理和搜集国内外文献,对激光雷达的技术特点及其在森林参数提...激光雷达(light detection and ranging,LiDAR)作为一门新兴的主动遥感技术,近年来由于在提取和反演森林参数水平上不断提高,被越来越多地应用于动物生态学研究中。本文通过整理和搜集国内外文献,对激光雷达的技术特点及其在森林参数提取和动物生境上的研究进展进行综述,指出当前基于LiDAR的森林参数反演算法主要服务于森林资源调查或林学研究,缺少对动物生态或生理意义相关的参数量化信息。目前该技术在国内的动物生态学方面的应用较少,尚未见文章发表。通过总结国外学者的研究,分别从动物生境选择与三维森林结构的关系、栖息地立体生境制图、生物多样性评估和物种分布模型预测三个方面综述了LiDAR在动物生态学研究中的应用现状。相比传统方法,LiDAR技术提供的高精度三维结构信息,能够显著提高动物生境质量的评估、生物多样性的监测水平和物种分布模型的评价精度,有利于从机理上加深对物种生境选择和集群过程的理解。但目前LiDAR技术的应用主要集中在对已知的生态关系研究,尤其是冠层结构与动物分布的关系,缺少对林下层生活的动物生境质量和生物多样性的监测和评估,同时很多有关动物生存和繁衍与立体生境的关系研究有待从LiDAR数据中进一步挖掘分析。未来应加强对森林林下层三维信息的提取,提高林下层动物生境质量和生物多样性的监测水平,同时建立适用于动物生态和生理意义相关的参数,为动物生境质量和生物多样性的评估提供标准的量化指标。展开更多
This study examines the impact of variations in side-blowing airflow velocity on plasma generation,combustion wave propagation mechanisms,and surface damage in fused silica induced by a combined millisecond-nanosecond...This study examines the impact of variations in side-blowing airflow velocity on plasma generation,combustion wave propagation mechanisms,and surface damage in fused silica induced by a combined millisecond-nanosecond pulsed laser.The airflow rate and pulse delay are the main experimental variables.The evolution of plasma motion was recorded using ultrafast time-resolved optical shadowing.The experimental results demonstrate that the expansion velocities of the plasma and combustion wave are influenced differently by the sideblowing airflow at different airflow rates(0.2 Ma,0.4 Ma,and 0.6 Ma).As the flow rate of the sideblow air stream increases,the initial expansion velocities of the plasma and combustion wave gradually decrease,and the side-blow air stream increasingly suppresses the plasma.It is important to note that the target vapor is always formed and ionized into plasma during the combined pulse laser action.Therefore,the side-blown airflow alone cannot completely clear the plasma.Depending on the delay conditions,the pressure of the side-blowing airflow,the influence of inverse Bremsstrahlung radiation absorption and target surface absorption mechanisms can lead to a phenomenon known as the double combustion waves when using a nanosecond pulse laser.Both simulation and experimental results are consistent,indicating the potential for further exploration of fused silica targets in the laser field.展开更多
基金supported by the National Natural Science Foundation of China(52171166,52101194,11972372 and U20A20231)the Fundamental Research Funds for the Central Universities(531118010621)the Postgraduate Scientific Research Innovation Project of Hunan Province(CX20210076).
文摘激光雷达(light detection and ranging,LiDAR)作为一门新兴的主动遥感技术,近年来由于在提取和反演森林参数水平上不断提高,被越来越多地应用于动物生态学研究中。本文通过整理和搜集国内外文献,对激光雷达的技术特点及其在森林参数提取和动物生境上的研究进展进行综述,指出当前基于LiDAR的森林参数反演算法主要服务于森林资源调查或林学研究,缺少对动物生态或生理意义相关的参数量化信息。目前该技术在国内的动物生态学方面的应用较少,尚未见文章发表。通过总结国外学者的研究,分别从动物生境选择与三维森林结构的关系、栖息地立体生境制图、生物多样性评估和物种分布模型预测三个方面综述了LiDAR在动物生态学研究中的应用现状。相比传统方法,LiDAR技术提供的高精度三维结构信息,能够显著提高动物生境质量的评估、生物多样性的监测水平和物种分布模型的评价精度,有利于从机理上加深对物种生境选择和集群过程的理解。但目前LiDAR技术的应用主要集中在对已知的生态关系研究,尤其是冠层结构与动物分布的关系,缺少对林下层生活的动物生境质量和生物多样性的监测和评估,同时很多有关动物生存和繁衍与立体生境的关系研究有待从LiDAR数据中进一步挖掘分析。未来应加强对森林林下层三维信息的提取,提高林下层动物生境质量和生物多样性的监测水平,同时建立适用于动物生态和生理意义相关的参数,为动物生境质量和生物多样性的评估提供标准的量化指标。
基金supported by the National Natural Science Foundation of China(No.52071093,51871069)the Fundamental Research Funds for the Central Universities,China(No.3072021CF1008)the Open Funds of the State Key Laboratory of Rare Earth Resource Utilization,China(No.RERU2020012)。
基金funded by the International Science and Technology Cooperation Project of Jilin Provincial Department of Science and Technology(No.20230402078GH)。
文摘This study examines the impact of variations in side-blowing airflow velocity on plasma generation,combustion wave propagation mechanisms,and surface damage in fused silica induced by a combined millisecond-nanosecond pulsed laser.The airflow rate and pulse delay are the main experimental variables.The evolution of plasma motion was recorded using ultrafast time-resolved optical shadowing.The experimental results demonstrate that the expansion velocities of the plasma and combustion wave are influenced differently by the sideblowing airflow at different airflow rates(0.2 Ma,0.4 Ma,and 0.6 Ma).As the flow rate of the sideblow air stream increases,the initial expansion velocities of the plasma and combustion wave gradually decrease,and the side-blow air stream increasingly suppresses the plasma.It is important to note that the target vapor is always formed and ionized into plasma during the combined pulse laser action.Therefore,the side-blown airflow alone cannot completely clear the plasma.Depending on the delay conditions,the pressure of the side-blowing airflow,the influence of inverse Bremsstrahlung radiation absorption and target surface absorption mechanisms can lead to a phenomenon known as the double combustion waves when using a nanosecond pulse laser.Both simulation and experimental results are consistent,indicating the potential for further exploration of fused silica targets in the laser field.
