This study was conducted in Erdaobaihe River passing through the broadleaved and Korean pine forest located on the north slope of Changbai Mountain. In-stream large woody debris (LWD) in two segments of the river chan...This study was conducted in Erdaobaihe River passing through the broadleaved and Korean pine forest located on the north slope of Changbai Mountain. In-stream large woody debris (LWD) in two segments of the river channel was investigated with base diameter, top diameter, length, and decay class. To study relationship between in-stream LWD and adjacent riparian forest, species of each log of LWD in segment 1 was identified, and the riparian forest was examined by setting a 32m?4 m quadrat consisting of twelve 8m?m small quadrats. The results showed that, in segment 1, in-stream LWD loading was 1.733 m3/100m or 10.83 m3hm-2, and in segment 2, it was 1.709m3/100m or 21.36 m3hm-2. In-stream LWD in decay class III and IV were accounted for a high proportion, which was different from that in the broadleaved and Korean pine forest, and the possible reason might be different decomposing velocities due to different decomposing conditions. Logs of LWD in stream and living trees in riparian forest declined as diameter increased, and it was in a reverse J-shaped distribution except logs of LWD in segment 1 in the first diameter class. Volumes of LWD in stream and living trees in riparian forest increased as diameter increased, and it was in a typical J-shaped distribution. Loading and species component of in-stream LWD were correlative to status of riparian forest to a certain extent, and there also existed difference. Comparing the correlation and difference was helpful to study on dynamic of the riparian forest.展开更多
In present paper the genus Rhithrogena Eaton from Chinese mainland, including a new species to science (Rhithrogena lutea, sp. nov.), 2 new record species from China (R. bajkovae Sowa, R. lepnevae Brodsky) and 3 known...In present paper the genus Rhithrogena Eaton from Chinese mainland, including a new species to science (Rhithrogena lutea, sp. nov.), 2 new record species from China (R. bajkovae Sowa, R. lepnevae Brodsky) and 3 known species [R. wuyinensis (Gui et al.) (comb. nov.), R. trispina Zhou et Zheng, R. orientalis You (= R. sangangensis You, new synonym)] are revised besed on the imaginal specimens. A key to 7 species imagos is provided. All materials in this study are deposited in Nanjing Normal University.展开更多
Hydropower development in China is concentrated in the country's western regions.Among all the rivers in China,the lower course of the Jinsha River contains the richest hydro-energy resource,and therefore,4 mammot...Hydropower development in China is concentrated in the country's western regions.Among all the rivers in China,the lower course of the Jinsha River contains the richest hydro-energy resource,and therefore,4 mammoth hydropower plants are under construction on this particular section of the river at Wudongde,Baihetan,Xiluodu,and Xiangjiaba.The water-blocking structures of the hydropower facilities at Wudongde,Baihetan and Xiluodu are all arch dams of around 300 m high.In view of changes in the geological conditions at the foundation of the Xiluodu dam on the riverbed after excavation started,the designs of expanding foundation surface excavation and dovetailing the dam body and foundation rock on both upstream and downstream sides were introduced,allowing the arch dam and foundation to fit each other and improving the stress conditions of the dam body and foundation.By dividing the dam body into various concrete sections,the dynamic properties of concrete were adequately adjusted to the distribution of stress in the dam body.In addition,the use of the most optimal concrete material and mixture ratio allowed thermodynamics of concrete to satisfy the requirements of the strength,durability,temperature control and crack prevention of the concrete.Moreover,rigorous temperature control measures were introduced to prevent harmful cracking,thus enhancing the integrity of the arch dam.Furthermore,sophisticated construction machinery,scientific testing methods,and sound construction techniques were employed to ensure the uniformity and reliability of concrete placement.The "Digital Dam" for the Xiluodu project,which is based on the theory of total life cycle,has supplied strong support for construction process control and decision-making.展开更多
基金This paper was supported by the Chinese Academy of Sciences (KZCX2-406) and National Natural Science Foundation of China (NSFC39970123) and Changbai Mountain Open Research Station.
文摘This study was conducted in Erdaobaihe River passing through the broadleaved and Korean pine forest located on the north slope of Changbai Mountain. In-stream large woody debris (LWD) in two segments of the river channel was investigated with base diameter, top diameter, length, and decay class. To study relationship between in-stream LWD and adjacent riparian forest, species of each log of LWD in segment 1 was identified, and the riparian forest was examined by setting a 32m?4 m quadrat consisting of twelve 8m?m small quadrats. The results showed that, in segment 1, in-stream LWD loading was 1.733 m3/100m or 10.83 m3hm-2, and in segment 2, it was 1.709m3/100m or 21.36 m3hm-2. In-stream LWD in decay class III and IV were accounted for a high proportion, which was different from that in the broadleaved and Korean pine forest, and the possible reason might be different decomposing velocities due to different decomposing conditions. Logs of LWD in stream and living trees in riparian forest declined as diameter increased, and it was in a reverse J-shaped distribution except logs of LWD in segment 1 in the first diameter class. Volumes of LWD in stream and living trees in riparian forest increased as diameter increased, and it was in a typical J-shaped distribution. Loading and species component of in-stream LWD were correlative to status of riparian forest to a certain extent, and there also existed difference. Comparing the correlation and difference was helpful to study on dynamic of the riparian forest.
基金National Natural Sciences Foundation of China (30300037)
文摘In present paper the genus Rhithrogena Eaton from Chinese mainland, including a new species to science (Rhithrogena lutea, sp. nov.), 2 new record species from China (R. bajkovae Sowa, R. lepnevae Brodsky) and 3 known species [R. wuyinensis (Gui et al.) (comb. nov.), R. trispina Zhou et Zheng, R. orientalis You (= R. sangangensis You, new synonym)] are revised besed on the imaginal specimens. A key to 7 species imagos is provided. All materials in this study are deposited in Nanjing Normal University.
文摘Hydropower development in China is concentrated in the country's western regions.Among all the rivers in China,the lower course of the Jinsha River contains the richest hydro-energy resource,and therefore,4 mammoth hydropower plants are under construction on this particular section of the river at Wudongde,Baihetan,Xiluodu,and Xiangjiaba.The water-blocking structures of the hydropower facilities at Wudongde,Baihetan and Xiluodu are all arch dams of around 300 m high.In view of changes in the geological conditions at the foundation of the Xiluodu dam on the riverbed after excavation started,the designs of expanding foundation surface excavation and dovetailing the dam body and foundation rock on both upstream and downstream sides were introduced,allowing the arch dam and foundation to fit each other and improving the stress conditions of the dam body and foundation.By dividing the dam body into various concrete sections,the dynamic properties of concrete were adequately adjusted to the distribution of stress in the dam body.In addition,the use of the most optimal concrete material and mixture ratio allowed thermodynamics of concrete to satisfy the requirements of the strength,durability,temperature control and crack prevention of the concrete.Moreover,rigorous temperature control measures were introduced to prevent harmful cracking,thus enhancing the integrity of the arch dam.Furthermore,sophisticated construction machinery,scientific testing methods,and sound construction techniques were employed to ensure the uniformity and reliability of concrete placement.The "Digital Dam" for the Xiluodu project,which is based on the theory of total life cycle,has supplied strong support for construction process control and decision-making.
