为提高复杂海洋环境中无人机自主降落时分割目标的实时性和精确性,研究主干网络和浅深层特征对分割算法性能的影响问题,基于DeepLabV3+框架建立一种基于主干网络浅深层特征的无人机海上分割(shallow and deep features of backbone,SDFB...为提高复杂海洋环境中无人机自主降落时分割目标的实时性和精确性,研究主干网络和浅深层特征对分割算法性能的影响问题,基于DeepLabV3+框架建立一种基于主干网络浅深层特征的无人机海上分割(shallow and deep features of backbone,SDFB)算法。首先,针对风浪扰动降低目标稳定性的问题,优化MobileNetV2结构提出一种特征提取方法,解决了算法无法处理短时间目标变化较大图像的问题;然后,针对深层特征输出通道数较多且存在不均匀分布大气湍流噪声的问题,利用本地全局信息选择性地聚合特征,提出一种特征筛选机制,剔除冗余通道的同时解决了算法对环境噪声敏感度高的问题;其次,针对光照不匀降低目标边界清晰度问题,从浅层空间维度和深层通道维度中提取轮廓信息建立一种并行轮廓学习机制,解决了算法利用轮廓特征效率低的问题;最后,针对障碍物遮挡破坏目标特征完整性问题,融合优化后的条带池化建立一种特征融合机制,解决了算法无法联系离散分布特征问题。实验表明,SDFB算法的实时性和精确性均高于其他算法,能够更好地适应海上场景无人机分割目标需求。展开更多
This paper summarized the possible physiological mechanism by which anthocyanins strengthen the tolerance of plants to drought. Drought stress can in-duce plant cel s to synthesize and accumulate anthocyanins. The pho...This paper summarized the possible physiological mechanism by which anthocyanins strengthen the tolerance of plants to drought. Drought stress can in-duce plant cel s to synthesize and accumulate anthocyanins. The photochemical properties, subcel ular accumulation sites and spatial distributions in plant organs and tissues of anthocyanins determine their function of strengthening plant tolerance, which is realized by three possible physiological mechanisms： （1） anthocyanins and their chelated metal ions can optimize the osmoregulation ability of the plant cel s by directly acting as the osmoregulation substances of the cel s, （2） anthocyanins with suitable spatial locations can reduce the photoinhibition of the plants under drought stresses, （3） anthocyanins can effectively maintain and improve the active oxygen-scavenging capacity of the plant cel s under drought conditions. Therein, that the anthocyanins enhance the antioxidant capacity of the plant cel s under drought stresses is probably the main reason for the anthocyanins to strengthen the drought tolerance of plants. This review could provide a reference for the mechanism re-search of the drought resistance and the breeding of the drought-resistant cultivars for the plants holding the ability to synthesize and accumulate anthocyanins.展开更多
We investigate the fluorescence quenching of Rhodamine 6G （R6G）, a well known laser dye with a high fluorescence quantum yield, by as-synthesized graphene oxide （GO） in aqueous solution, which is found to be rathe...We investigate the fluorescence quenching of Rhodamine 6G （R6G）, a well known laser dye with a high fluorescence quantum yield, by as-synthesized graphene oxide （GO） in aqueous solution, which is found to be rather efficient. By means of steady-state and time-resolved fluorescence spectroscopy combined with detailed analysis about the linear absorption vari- ation for this R6G-GO system, the pertinent quenching mechanism has been elucidated to be a combination of dynamic and static quenching. Possible ground-state complexes be- tween R6G and GO during the static quenching have also been suggested. Furthermore, the direction of photoindueed electron transfer between R6G and GO has been discussed.展开更多
文摘为提高复杂海洋环境中无人机自主降落时分割目标的实时性和精确性,研究主干网络和浅深层特征对分割算法性能的影响问题,基于DeepLabV3+框架建立一种基于主干网络浅深层特征的无人机海上分割(shallow and deep features of backbone,SDFB)算法。首先,针对风浪扰动降低目标稳定性的问题,优化MobileNetV2结构提出一种特征提取方法,解决了算法无法处理短时间目标变化较大图像的问题;然后,针对深层特征输出通道数较多且存在不均匀分布大气湍流噪声的问题,利用本地全局信息选择性地聚合特征,提出一种特征筛选机制,剔除冗余通道的同时解决了算法对环境噪声敏感度高的问题;其次,针对光照不匀降低目标边界清晰度问题,从浅层空间维度和深层通道维度中提取轮廓信息建立一种并行轮廓学习机制,解决了算法利用轮廓特征效率低的问题;最后,针对障碍物遮挡破坏目标特征完整性问题,融合优化后的条带池化建立一种特征融合机制,解决了算法无法联系离散分布特征问题。实验表明,SDFB算法的实时性和精确性均高于其他算法,能够更好地适应海上场景无人机分割目标需求。
基金Supported by the National Natural Science Foundation of China(31060045,31260091)~~
文摘This paper summarized the possible physiological mechanism by which anthocyanins strengthen the tolerance of plants to drought. Drought stress can in-duce plant cel s to synthesize and accumulate anthocyanins. The photochemical properties, subcel ular accumulation sites and spatial distributions in plant organs and tissues of anthocyanins determine their function of strengthening plant tolerance, which is realized by three possible physiological mechanisms： （1） anthocyanins and their chelated metal ions can optimize the osmoregulation ability of the plant cel s by directly acting as the osmoregulation substances of the cel s, （2） anthocyanins with suitable spatial locations can reduce the photoinhibition of the plants under drought stresses, （3） anthocyanins can effectively maintain and improve the active oxygen-scavenging capacity of the plant cel s under drought conditions. Therein, that the anthocyanins enhance the antioxidant capacity of the plant cel s under drought stresses is probably the main reason for the anthocyanins to strengthen the drought tolerance of plants. This review could provide a reference for the mechanism re-search of the drought resistance and the breeding of the drought-resistant cultivars for the plants holding the ability to synthesize and accumulate anthocyanins.
基金This work was supported by the National Basic Research Program of China （No.2010CB923300）, the National Natural Science Foundation of China （No.91127042 and No.21173205）, the Chinese Academy of Sciences （No.XDB01020000）, the FR- FCUC （No.WK2340000012）, the USTC-NSRL Joint Funds （No.KY2340000021）, and the National Under- graduate Innovative Training Program of Ministry of Education （No.201210358064）.
文摘We investigate the fluorescence quenching of Rhodamine 6G （R6G）, a well known laser dye with a high fluorescence quantum yield, by as-synthesized graphene oxide （GO） in aqueous solution, which is found to be rather efficient. By means of steady-state and time-resolved fluorescence spectroscopy combined with detailed analysis about the linear absorption vari- ation for this R6G-GO system, the pertinent quenching mechanism has been elucidated to be a combination of dynamic and static quenching. Possible ground-state complexes be- tween R6G and GO during the static quenching have also been suggested. Furthermore, the direction of photoindueed electron transfer between R6G and GO has been discussed.
