对Lackenby浅水航速修正方法和Raven浅水航速修正方法进行介绍,并结合30万吨级超大型油船(Very Large Crude Carrier,VLCC)、40万吨级矿砂船和18万吨级散货船等3种典型船型的实船航速试验数据对这2种方法进行对比。结果表明:当水深临近...对Lackenby浅水航速修正方法和Raven浅水航速修正方法进行介绍,并结合30万吨级超大型油船(Very Large Crude Carrier,VLCC)、40万吨级矿砂船和18万吨级散货船等3种典型船型的实船航速试验数据对这2种方法进行对比。结果表明:当水深临近浅水上限时,Raven方法相比Lackenby方法对航速修正结果不利;当水深接近深水标准时,Raven方法的浅水航速修正结果与Lackenby方法相近。在此基础上,给出典型肥大型低速船在应用ITTC 2017采纳的Raven方法时选择试航水深的建议。展开更多
In many songbirds, the space use of breeders is well studied but poorly understood for non-breeders. In common ravens, some studies of non-breeders indicate high vagrancy with large individual differences in home rang...In many songbirds, the space use of breeders is well studied but poorly understood for non-breeders. In common ravens, some studies of non-breeders indicate high vagrancy with large individual differences in home range size, whereas others show that up to 40% of marked non-breeders can be regularly observed at the same anthropogenic food source over months to years. The aim of this study was to provide new insights on ravens＇ behavior during dispersal in the Eastern Alps. We deployed Global Positioning System （GPS） loggers on 10 individuals to gather accurate spatial and temporal information on their movements to quantify： 1） the dimension of the birds＇ space use （home range size with seasonal effects and daily/long-term travel distances）, 2） how long they stayed in a dispersal stage of wandering as opposed to settling temporarily, and 3） their destination of movements. We recorded movements of up to 40km per hour, more than 160km within 1 day and more than 11,000 km within 20 months, indicating high vagrancy. Switching frequently between temporarily settling and travelling large distances in short time intervals leads to extensive home ranges, which also explains and com- bines the different findings in the literature. The destinations are rich anthropogenic food sources, where the birds spent on average 75% of their time. We discuss how ravens may find these ＂feeding hot spots＂ and which factors may influence their decision to stay/leave a site. The strong dependence on anthropogenic resources found in this population may have implications for site management and conservation issues.展开更多
The raven is a narrative poem written by American writer Edgar Allan Poe. It tells of a talking raven's mysterious visit in a midnight to a distraught lover, tracing the lover's slow fall into madness. The lov...The raven is a narrative poem written by American writer Edgar Allan Poe. It tells of a talking raven's mysterious visit in a midnight to a distraught lover, tracing the lover's slow fall into madness. The lover is lamenting the loss of his beloved, Lenore. The raven, sitting on a bust of Pallas, seems to further instigate his distress with its constant repetition of the word"Nevermore".展开更多
Poe’s "Raven" is one of the greatest masterpieces in American literary history. Learners are analyzing it from various perspectives, its image, its massage, its function to Poe’s creative principles, etc. ...Poe’s "Raven" is one of the greatest masterpieces in American literary history. Learners are analyzing it from various perspectives, its image, its massage, its function to Poe’s creative principles, etc. This paper shall further discuss the sound used in the poem. Thanks to the sound, it becomes one of most beautiful poems in the world.展开更多
文摘对Lackenby浅水航速修正方法和Raven浅水航速修正方法进行介绍,并结合30万吨级超大型油船(Very Large Crude Carrier,VLCC)、40万吨级矿砂船和18万吨级散货船等3种典型船型的实船航速试验数据对这2种方法进行对比。结果表明:当水深临近浅水上限时,Raven方法相比Lackenby方法对航速修正结果不利;当水深接近深水标准时,Raven方法的浅水航速修正结果与Lackenby方法相近。在此基础上,给出典型肥大型低速船在应用ITTC 2017采纳的Raven方法时选择试航水深的建议。
文摘In many songbirds, the space use of breeders is well studied but poorly understood for non-breeders. In common ravens, some studies of non-breeders indicate high vagrancy with large individual differences in home range size, whereas others show that up to 40% of marked non-breeders can be regularly observed at the same anthropogenic food source over months to years. The aim of this study was to provide new insights on ravens＇ behavior during dispersal in the Eastern Alps. We deployed Global Positioning System （GPS） loggers on 10 individuals to gather accurate spatial and temporal information on their movements to quantify： 1） the dimension of the birds＇ space use （home range size with seasonal effects and daily/long-term travel distances）, 2） how long they stayed in a dispersal stage of wandering as opposed to settling temporarily, and 3） their destination of movements. We recorded movements of up to 40km per hour, more than 160km within 1 day and more than 11,000 km within 20 months, indicating high vagrancy. Switching frequently between temporarily settling and travelling large distances in short time intervals leads to extensive home ranges, which also explains and com- bines the different findings in the literature. The destinations are rich anthropogenic food sources, where the birds spent on average 75% of their time. We discuss how ravens may find these ＂feeding hot spots＂ and which factors may influence their decision to stay/leave a site. The strong dependence on anthropogenic resources found in this population may have implications for site management and conservation issues.
文摘The raven is a narrative poem written by American writer Edgar Allan Poe. It tells of a talking raven's mysterious visit in a midnight to a distraught lover, tracing the lover's slow fall into madness. The lover is lamenting the loss of his beloved, Lenore. The raven, sitting on a bust of Pallas, seems to further instigate his distress with its constant repetition of the word"Nevermore".
文摘Poe’s "Raven" is one of the greatest masterpieces in American literary history. Learners are analyzing it from various perspectives, its image, its massage, its function to Poe’s creative principles, etc. This paper shall further discuss the sound used in the poem. Thanks to the sound, it becomes one of most beautiful poems in the world.
