中国科学院机构知识库网格系统: 检索

Longitudinal variations in channel morphology of an ephemeral stream from upland to lowland, Daihai Lake basin, North China 期刊论文 OAI收割
GEOMORPHOLOGY, 2021, 卷号: 372, 页码: 16
作者: Tan, Chengpeng; Feng, Shuangqi; Zhao, Xiaoming; Shan, Xin; Feng, Shenglun

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收藏 | 浏览/下载：25/0 | 提交时间：2021/09/29

Channel morphology Ephemeral stream Monsoon climate Flow regime UAV photogrammetry

Physical layer design for free space optical communication (EI CONFERENCE) 会议论文 OAI收割
2012 International Conference on Control Engineering and Communication Technology, ICCECT 2012, December 7, 2012 - December 9, 2012, Shenyang, Liaoning, China
作者: Wang H.; Zhang Q.; Guo J.; Guo J.; Wang H.

收藏 | 浏览/下载：31/0 | 提交时间：2013/03/25

A small size Free Space Optical Communication System is introduced including the hardware and the hardware specified physical layer protocol. In detail the rapid synchronization method to reduce the handshake bandwidth requirement is demonstrated. The hardware of the system includes the laser driver system the signal amplifying and shaping system the data interface system. The hardware specified physical layer protocol is used to interface the outer data serialize and deserialize the data stream check transmission errors and schedule the data transmission. The overall system is a FIFO-like system and the user can use it as if he's operating a FIFO. The system is designed mainly for terrestrial FSO link whose signal channel is the atmosphere. Due to the complex composition and activity of the atmosphere this signal channel brings in great influence on the transmitting laser in it for example the absorption and scattering of the atmosphere molecules and aerosols the scintillation of received laser power caused by the turbulence of the atmosphere all of which results in a much higher Bit Error Rate (BER) of the communication system than wired communication systems leading to frequent resynchronization. In our system the sampling clock is generated locally using multi-phase sampling technique rather than PLLbased clock recovery which helps to rapid synchronization. 2012 IEEE.

Rehabilitation of a debris-flow prone mountain stream in southwestern China - Strategies, effects and implications SCI/SSCI论文 OAI收割
2012
作者: Zhang K.

收藏 | 浏览/下载：34/0 | 提交时间：2012/09/04

Steep headwater stream Rehabilitation Riparian vegetation Streambed structure Stream ecology land-use change new-zealand step-pools sediment production channel response mangatu-forest gully erosion puerto-rico restoration morphology

Optical transmission system based on 10GBASE-X (EI CONFERENCE) 会议论文 OAI收割
2010 3rd International Conference on Advanced Computer Theory and Engineering, ICACTE 2010, August 20, 2010 - August 22, 2010, Chengdu, China
作者: Gao S.-J.

收藏 | 浏览/下载：31/0 | 提交时间：2013/03/25

In order to further enhance the bandwidth of the data communication system in theodolite The whole design of the PMD is realized by using Xenpak optical module. Its duty is responsible for converting 4-channel parallel 3.125Gbps data stream into a serial 10.3126Gbps data stream a single channel serial optical transmission system was designed based on the studying of the 10BASE-X Gigabit Ethernet physical layer technology which meets the IEEE standard. The conversion between the 64-bit 156.25MHz TTL signals and the 4 channel 3.125Gbps PCML differential signals is carried out by FPGA and sending out it in the form of light signals. The experimental results show that data transmission capacity was achieved a 10Gbps in the single-channel optical transmission system. It can conduct short distance transmission. The system delay is about 31lns. The bit error rates no more than 10-12 which satisfies the system demand. 2010 IEEE.

Discrimination of channel patterns for alluvial rivers based on the sediment concentration to water discharge ratio SCI/SSCI论文 OAI收割
2010
作者: Yan M.

收藏 | 浏览/下载：19/0 | 提交时间：2012/06/08

channel patterns discrimination of channel patterns sediment concentration to water discharge ratio stream power of rivers channel boundary condition of rivers complex response classification china

Transceiving protocol designc for a free space optical communication system (EI CONFERENCE) 会议论文 OAI收割
2008 International Conference on Optical Instruments and Technology: Optical Systems and Optoelectronic Instruments, November 16, 2008 - November 19, 2008, Beijing, China
Hualong W.; Wanxin S.; Zhongbao X.

收藏 | 浏览/下载：58/0 | 提交时间：2013/03/25

A new transceiving protocol is demonstrated for a Free Space Optical (FSO) communication system and it's discussed in two parts: the transmitting protocol and the receiving protocol. During the discussion of these two parts the cooperation of them is also discussed. Different from wired communication an FSO system modulates the data on a narrow beam of laser transmitting through the free space or the atmosphere and the protocol presented in this paper is mainly optimized for terrestrial Free Space Optical links in which the signal channel of the system is mainly the atmosphere. Due to the complex composition and activity of the atmosphere this signal channel brings in great influence on the transmitting laser in it for example the absorption and scattering of the atmosphere molecules and aerosols the scintillation of received laser power caused by the turbulence of the atmosphere all of which results in a much higher Bit Error Rate (BER) of the communication system. Thus in designing a protocol for an FSO system more effort should be taken in the encoding of the data stream the synchronization of the data stream error checking and exception handling. The main function of the transmitting protocol includes interfacing the outer input data with a parallel port buffering the input data encoding the input data stream serializing the parallel data and output the serialized data. It also has an output management unit to manage the activity of each part of the transmitting protocol. The main function of the receiving protocol includes filtering and synchronizing the input serial data stream paralleling the serial data stream decoding the input data error checking exception handling and interfacing the outer receiver with a parallel port. The entire transceiving protocol could be programmed into a single FPGA chip to improve system integrity and reduce the system cost. The presented protocol could be taken as "protocol transparent" for outer interfaces meaning that when interfacing the presented system to an outer system you don't have to consider what protocol the outer system transceiving data stream is under for example the TCP/IP protocol or anything else in the case that its I/O interface is a parallel port. Simulation and final experiment prove that the protocol presented is working fine at a certain bit rate scale. 2009 SPIE.

Temporal changes in suspended sediment transport in a gullied loess basin: the lower Chabagou Creek on the Loess Plateau in China SCI/SSCI论文 OAI收割
2008
Fang H. Y.; Cai Q. G.; Chen H.; Li Q. Y.

收藏 | 浏览/下载：24/0 | 提交时间：2012/06/08

sediment peak peak discharge hysteresis loop hyperconcentrated flow Chabagou Creek hyperconcentrated flows drainage-basin river basins flood catchments dynamics deposits channel fluxes stream

Least action principle, equilibrium states, iterative adjustment and the stability of alluvial channels SCI/SSCI论文 OAI收割
2008
Nanson G. C.; Huang H. Q.

收藏 | 浏览/下载：44/0 | 提交时间：2012/06/08

least action equilibrium states extremal hypotheses iterative change variational principles river patterns channel stability formed straight rivers arid central australia minimum stream power gravel-bed rivers hydraulic geometry mobile-bed anabranching rivers energy-dissipation extremal hypotheses northern plains

Statistical relations between geomorphic parameters - A case study of the Yunnan reach of the Lancangjiang River in southwestern China SCI/SSCI论文 OAI收割
2007
Wang S. J.; Wu S. H.; Dai E. F.

收藏 | 浏览/下载：76/0 | 提交时间：2012/06/08

river catchment geomorphic parameter correlation river characteristics fluvial response channel geometry stream power basin system delta

Hydrological processes of an anastomosing river system on the Zhujiang River Delta, China SCI/SSCI论文 OAI收割
2004
Wang S. J.; Ni J. R.; Wang G. Q.; Cheng D. S.; Zhang O. Y.

收藏 | 浏览/下载：26/0 | 提交时间：2012/06/08

channel gradient width/depth ratio suspended sediment concentration discharge stream velocity central australia okavango fan cooper creek sedimentation morphology avulsion canada classification examples deposits