Research On The Detecting Electrodes And The Propagation Of Electric Field In Ocean

The underwater electric field detection plays an important role in developing marine economy,as its wide applications in many fields,such as geological exploration,pipeline detection,underwater target detection,underwater weapon fuze and ship communication.The development of high-performance marine electric field detection electrodes,the core component of the detection system,is of the greatest interest.Considering the complex ocean environment,our work not only focused on the electrodes itself,but also on the underwater detection.In details,the main research work of this thesis is as follows:In order to improve the performance of carbon fiber electrodes on the low frequency electric field response,a new kind of carbon fiber ocean electric field electrode was prepared by dense nitric acid oxidation + grafting of gammaaminoethylaminopropyltrimethoxysilane(KH-792).The electrochemical properties of carbon fiber electrodes and the changes of their performance on electric field response before and after modification were investigated.The surface morphology and functional groups of the modified electrodes were changed before and after modification.The results showed that the surface roughness of carbon fibers oxidized by concentrated nitric acid was greater and the surface area was larger.After KH-792 was grafted,nitrogen and oxygen functional groups were introduced into the surface of the modified carbon fibers,and the surface activity was improved.The modified electrodes can correctly respond to small signals in low frequency.The distortion of the response for the modified carbon fiber electrodes to the emitted signal with electric field strength of 6.2m V/m was 37.638% and 12.246% at the frequency of 1m Hz and10 m Hz,respectively.The distortion of the modified carbon fiber electrodes was significantly reduced after the modification.A simulation model based on finite element method was established for multiboundary and layered ocean electric field to study the electric field transmission characteristics in complex ocean environment.By setting up the field test platform,the finite element simulation model was verified.This model was used to study the transmission characteristics of ocean electric field in radiation field.The influence of measuring electrodes,sources and environmental parameters on electric field transmission was also investigated,which provides guidance for the electric field detection in the actual ocean environment.