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991.
Since P. R. China has experienced extensive land resource use, environmental degradation, lagging rural development and other difficulties in 20th century, urban countryside integration and ecological planning has become an important subject to build a harmonious society in the 21st century. The country attempted to use complexity science and ecological thinking based on recognizing the relationship between the city and countryside and raising the city countryside space ecology coupling concept to construct a city countryside space planning methods system consisting of the identification of urban and rural land uses, urban and rural non construction land planning, city countryside coupled environmental conditions assessment, coordinated city countryside space development and city countryside space system fractal optimization, and more.  相似文献   
992.
This paper conducts the experimental study on the natural convection characteristics of cold water near the maximum density in horizontal annulus with the fixed inner radius ri=14 mm and different width l=6~18 mm. The temperature at outer wall is maintained at 0 ℃, and the temperature differences between the inner and outer walls range from 2 to 24 ℃. The results show that the heat transfer coefficient at inner wall increases with the increase of the annulus width. When the temperature difference is bellow 4 ℃ or above 8 ℃, the heat transfer coefficient increases with the increase of the temperature difference. When the temperature difference is between 4 ℃ and 8 ℃, it decreases with the increase of the temperature difference. The formula of heat transfer at inner walls is obtained by using the method of linear regression.  相似文献   
993.
The composition of SF6 decomposition products is directly associated with the safe operation of equipment. Through GC FTIR coupling technique,the SF6 decomposition products are divided, the qualitative analysis is made with FTIR to the outlier,and spectrogram was processed with subtract and searched the analogous one. Above data is used to generate the tridimensional atlas of infrared spectrum absorbance GC holding time. Single gas analysis is compared with local measurement, the foregoing method can make the qualitative analysis and quantitative analysis for the decomposition products, the fault features detected by gas composition and chroma is anastomotic with the actual fault, the result indicates that this method can be used in GIS fault diagnosis.  相似文献   
994.
We present an aeroelastic model design and method creation based on the case of an ±800 kV ultra high voltage (UHV) power transmission line from Xiang Jiaba to Shanghai, P. R. Chin, Both the centralized and discreted stiffness modeling methods are unsuitable for tower aeroelastic modeling. Taking these stiffness and aerodynamic characteristics into account, we introduce a new method to create an aeroelastic model that includes a semi rigid model segment and U shaped springs. Because the span of this transmission line is too long to fit within the wind tunnel in the same proportions as the tower, the proportions of the line model is condensed further. Aeroelastic test requirements can be satisfied by comparing theoretical analysis and actual measurements of the system model dynamics.  相似文献   
995.
The type and percentage of sand affect the gradation of coarse fine aggregate and the amount of spare mortar in concrete, which further affects the resistance of fresh concrete to initial plastic shrinkage. Taking into account the engineering characteristics of sand in the area of Chongqing, P. R. China, three fine aggregates composed of superfine, medium, mixed and manufactured sand, are used to prepare high performance concrete (HPC). The effects of these three fine aggregates on initial plastic shrinkage crack are investigated. The results show that the HPC prepared with superfine sand possesses a higher initial shrinkage value than HPC prepared with mixed or medium sand. An optimal sand percentage is necessary to reduce the initial shrinkage cracking of HPC prepared with mixed or medium sand.  相似文献   
996.
To counter deficient medical knowledge sharing and the low efficiency cooperative diagnosis between doctors, the knowledge flow from knowledge management (KM), knowledge acquisition and knowledge supply are established as the core info structure of a hospital KM model. This is done by combining heavy idea exchange, frequent updating, and intensive use of the medical knowledge. Three important knowledge flow(KF) operations (knowledge refreshing, knowledge migration and knowledge expansion) are proposed. By comparing hospital information management with hospital KM, a hospital KM method based on knowledge flow is constructed. The method emphasizes tracking, monitoring and controlling hospital wide comprehensive process of medical knowledge. A specific clinical diagnosis instance is given for detailed healthcare knowledge flow analysis.   相似文献   
997.
The knowledge of liquid flows in blast furnaces may play an important role in controlling the blast furnace process. Appropriate assumptions are given to represent the main characteristics of the liquid flow in blast furnaces, such as liquid streams being composed of unwetting liquid droplets, inertial force having little effect on the liquid flows, and mass exchange existing along the direction perpendicular to liquid flow. A mathematical model is built to predict the distribution of the liquid flow rate and the liquid flow range in packed beds. The scale of the numerical grid used to solve this model may not necessarily be reduced to the particle level. The predicted results of this model accord well with the observed data. This model is an alternative theory for the simulation of blast furnaces  相似文献   
998.
On the basis of identifying and analyzing harmful risk factors in the urea synthesis production process of a factory, the production process is assessed and analyzed using the Dow chemical company fire and explosion index method. The related indexes are f  相似文献   
999.
Dynamic responses of ultra high voltage transmission line ice shedding   总被引:1,自引:0,他引:1  
Numerical models of typical 500 kV ultra high voltage (UHV) transmission lines are set up in ABAQUS/CAE software. The dynamic response of the transmission lines with different structure parameters under various ice shedding load cases are analyzed, and th  相似文献   
1000.
A chip with smaller size and higher pixel density was designed to increase the chip’s pixel density in subretinal prosthesis. This chip was designed on 0.35 μm standard CMOS(complementary metal oxide semiconductor) technology of CHRT company, while the double inverter relaxation oscillator was chosen as the basic pixel circuit. By creating layout on Cadence software, the circuit was debugged and simulated. The experiment results show that the pixel circuit provide effective pulse signals whose values and frequencies can vary with photocurrent to stimulate retinal nerve cells. For the simulated layout, the pulse width was 0.26 ms, the frequency was 18~503 Hz, the pixel size was 65 μm×65 μm, and the chip size was 1.1 mm×1.1 mm. All of the parameters can satisfy the requirement to stimulate retinal nerve cells in physiology. The experiment results provide a good foundation for the following research.  相似文献   
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