摘要
通过冲积河流系统自动调整现象的分析，对系统自行镇定，自行适应环境的功能特性加深了认识，提出了自然信息是系统各个要素、各个层次、各个部分相互联系、制约的一种耦合基因或制约基因的新观点．系统之所以能够自动地吸收和消除干扰所造成的失谐或突变所引起的偏差，在于系统本身能“理解”如何有目的地行动．这种‘理解”和行动是通过信息反馈完成的．对这种信息及其反馈机制进行深人研究，对于揭示河流系统自组织机理、不同河型的成因，以及对其进行优化与调控，具有重要的意义．
By the analysis of the self-adjusting phenomenon of the alluvial river system, the following understandings were presented in this paper.1. As a natural open system, the alluvial river has functions of both,strong self-calmand self-adapting enviroment. As it is seen from figure 1, when the suspended load as anenvironment variable.ihcreases rapidly with increasing dischaarge in the first of rise of flood,all other hydraulic factors in the system will quickly 'sense' a binding from the input andcarry out act,ion with ends. For example, the velocity in(reases with increasing dischargewith a highter rate for satisfaction to requirement of the excess sediment transport. At the same time the elevation of stream bed tises gradually as a result of deposition. After thedischarge is in excess of 142m3 / s, the increasing rate of the suspended sediment load withdischarge increase has reiatively been on the decrease. under this circumstance the velocitywill again make a quick response to the change, that is, the rate of the velocity increase willbe less than one of the earlier stage. And at the moment the channel will be transposed froma depositing state to another scouring state. During the flood fall the deers.asing rate ofsed-:iment load as a function of discharge is between the change rate of the earlier state and Oneof the latter stage of the flood rise, Consequently the decreasing rate of the ye1Ocity is alsobetween the above two conditions and all other hydraulic factors of stream channel which contain each other such as the.depth and water-surface elevation , etc. may also respond tothe change and understand how to adjust themselvel with aim. Thereforethere is a close relation of echoing each other among the chanage loci of hydraulic factors, channel form and that of sediment load With discharge . It shows that the transport-ability of both water andsediment in siream channel will adjust to quantity of water and sediment coming from theupper reaches, and the channel system will again return to dynamic equilibrium after thesystem goes through the negative feedback during flood rise and fall. For this reason the al luvial river system has outstandingly controllable nature.2. The functions of self -calm and self-adapting of the system will be brought into playby natural information feedback feedback matters. The various parts in the system can'sense ' in time a change of restrictive condition through information feedback . They, then,will make self-regulation as a certain direction. It follows that the essence of natural information should be a rstrictive gene.3. The direcrion and goal of self-adjusting of a system are perfectly for preserving orrestoring its own calm, The self-adapting function of a .system, similarly, embodies afee'dback connection and adjusting goal between the system and its environment.4. It is achieved only through information feedback between matter and consciousnessfor man to control a system. Simultaneously, it also affects information feedback betweenmatters. For example, system engineering of Dujiangyan in China shown tri figure 2 is thisstate of affairs. its information feedback and adjustment are as follows:where E-water and sediment regime environment of the reach upper Dujiangyan, theMinjiang River; D-the engineerings of the Fish Mouth, the Feishayan spillway and theBaopingkou canal; M-the restrictive mechanism of the hydraulic,geomtry of stream chan-nel5.In the light of present level of science and technology, the control measure adoptedhas to start with constructing channel regulation works, i.e. altering and fixing form structure of system. Controlled targets, of coursed are the quantity, process, path, strength andspeed, etc. of mass and energy flow.6. There are four channels in control ways: (a) Controlling it outside the system. Ex.The reservoir at the three gorges will be built, which will,control the floods and channelprocesses of the middle and low.er reaches of the Yangtze River; (b) Setting up strain instal.lations against all possible sudden change events within the
出处
《南京大学学报（自然科学版）》
CSCD
1994年第2期344-352,共9页
Journal of Nanjing University（Natural Science）
关键词
河流地貌
系统
信息
反馈
Fluvial geomorphology , System, Information, Feedback
