Three stages of reform of collective forest tenure after reform and opening up are reviewed.The reform of forest tenure brings sharp increase of economic benefit.However,due to forest farmers' subjective pursuit f...Three stages of reform of collective forest tenure after reform and opening up are reviewed.The reform of forest tenure brings sharp increase of economic benefit.However,due to forest farmers' subjective pursuit for economic benefit and objective lack of necessary economic,financial and technical support,ecological hidden troubles are created.Based on these,we put forward countermeasures,including strengthening forest farmers' awareness of ecological protection and solving ecological problems in accordance with actual conditions of the region.展开更多
The principles,methods,technologies and application effects of several electromagneticmethods for the detection of the hidden danger of water gushing at the coalface were introduced.Also,emphasis was laid on expoundin...The principles,methods,technologies and application effects of several electromagneticmethods for the detection of the hidden danger of water gushing at the coalface were introduced.Also,emphasis was laid on expounding the methods,principles andeffects of down-hole detections by electric transmission tomography and transient electromagneticmethod.The potential of point power supplied in the underground homogeneoussemi-space,as well as the response to a low-resistivity abnormal body in file hemogeneoussemi-space,was simulated by adopting 3-D finite element method to interpretthe basic theory of the electric transmission tomography.The results of actual measurementshow that the mine electromagnetic method is sensitive to water-bearinglow-resistivity bodies and can play a unique role in detecting the hidden danger of watergushing at the coal face.展开更多
A large number of hydraulic concrete structures have hidden defects such as cracks, erosion, freeze and thaw, thermal fatigue, carbonization. These hidden defects seriously affect the strength, stability and durabilit...A large number of hydraulic concrete structures have hidden defects such as cracks, erosion, freeze and thaw, thermal fatigue, carbonization. These hidden defects seriously affect the strength, stability and durability of structures. These problems are studied mainly by single monitoring or diagnosis methods at present. The integration of multiple monitoring and diagnosis methods is not applied widely. Besides, the analysis theory on these problems is not developed very well. The systemic study on the aging mechanism of hydraulic concrete structures, time- variation model and health diagnosis is still not enough. The support for engineering practice is limited. Aimed at these major scientific and technological problems and combined with specific projects, study on detection of hidden defects and health diagnosis of hydraulic concrete structure has been carried out. This study includes the following content: field non-destructive examination of hidden defects of hydraulic concrete structures, seepage detection, the construction of in-situ sensing system, the combination of field detection and in-situ monitoring, the mechanism of crack, freeze and thaw, erosion and carbonization of hydraulic concrete structure, mechanism of combination aging; time-variation model of hydraulic concrete structure, theories and methods for health diagnosis of hydraulic concrete structures.展开更多
基金Supporte by Special Funds for Scientific Research of Forestry Public Welfare Industry " Technical Research and Demonstration for Ecological Environmental Protection of Wild Fauna and Flora Based on Forest Tenure Reform"(200904003)
文摘Three stages of reform of collective forest tenure after reform and opening up are reviewed.The reform of forest tenure brings sharp increase of economic benefit.However,due to forest farmers' subjective pursuit for economic benefit and objective lack of necessary economic,financial and technical support,ecological hidden troubles are created.Based on these,we put forward countermeasures,including strengthening forest farmers' awareness of ecological protection and solving ecological problems in accordance with actual conditions of the region.
基金Supported by the National Basic Research of China(2006CB202207)the National Natural Science Foundation of China(40674060)
文摘The principles,methods,technologies and application effects of several electromagneticmethods for the detection of the hidden danger of water gushing at the coalface were introduced.Also,emphasis was laid on expounding the methods,principles andeffects of down-hole detections by electric transmission tomography and transient electromagneticmethod.The potential of point power supplied in the underground homogeneoussemi-space,as well as the response to a low-resistivity abnormal body in file hemogeneoussemi-space,was simulated by adopting 3-D finite element method to interpretthe basic theory of the electric transmission tomography.The results of actual measurementshow that the mine electromagnetic method is sensitive to water-bearinglow-resistivity bodies and can play a unique role in detecting the hidden danger of watergushing at the coal face.
基金Supported by the Key Project of Chinese National Programs for Fundamental Research and Development (Grant No. 2002CB412707) Key Project of NNSF and Yalongjiang Hydroelectric Development Joint Research Fund (50539110, 50539030)+2 种基金 Science and Technology Support Plan (20006BAC14B03) National Natural Science Foundation Major Project (50539010)National Natural Science Foundation of China (Grant No. 50579010)
文摘A large number of hydraulic concrete structures have hidden defects such as cracks, erosion, freeze and thaw, thermal fatigue, carbonization. These hidden defects seriously affect the strength, stability and durability of structures. These problems are studied mainly by single monitoring or diagnosis methods at present. The integration of multiple monitoring and diagnosis methods is not applied widely. Besides, the analysis theory on these problems is not developed very well. The systemic study on the aging mechanism of hydraulic concrete structures, time- variation model and health diagnosis is still not enough. The support for engineering practice is limited. Aimed at these major scientific and technological problems and combined with specific projects, study on detection of hidden defects and health diagnosis of hydraulic concrete structure has been carried out. This study includes the following content: field non-destructive examination of hidden defects of hydraulic concrete structures, seepage detection, the construction of in-situ sensing system, the combination of field detection and in-situ monitoring, the mechanism of crack, freeze and thaw, erosion and carbonization of hydraulic concrete structure, mechanism of combination aging; time-variation model of hydraulic concrete structure, theories and methods for health diagnosis of hydraulic concrete structures.
