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201.
Abstract:In the modern society due to the increasingly high requirements on the environment circumstances, it is imperative to study the insulation coating.This paper introduces the testing method and heat insulating principle of the building external wal 相似文献
202.
HUANG Lei chang ZHANG Zhi guo HUANG Chun yan SUN Xu cai WANG Xiang rong 《保鲜与加工》2008,(4):27-32
We discussed the trends and challenges of rapid urbanization for modern landscape from a development viewpoint. We analyzed the problems of modern landscape in P. R. China. Based on ecological principles, we proposed a corresponding eco-thinking model composing eco-thinking of vision, culture, environmental protection and public participation. We carried out a case study of the south entrance of Tongniuling Scenic Spot in Dalian. We constructed diverse scenarios according to the leading factors selected by factor analysis. We assessed them with the Delphi method and public anticipation. The priority rating was, in order, scenario number 2 (48.3%), number 1 (30.5%) and number 3 (15.7%). Scenario number 2 was the best for its prominent visual image, typical culture presentation, weaker disturbance and reasonable cost. Scenario numbers 1 and 3 took culture and environment as leading factors, respectively. The cost of the former was low while the latter was high. Our work indicates that the eco-thinking model, as a brand-new thinking for modern landscape, is feasible. 相似文献
203.
Based on summary and analysis of the main research findings regarding R μ T relations for a single degree of freedom system, the following two important conclusions can be drawn: 1) In general, these research findings are consistent with each other. The R μ T rule can be an important reference criterion for seismic design. 2) Proper design and extendibility ensure the relatively satisfactory performance of the structure under stronger earthquake action. 相似文献
204.
Luzhou is a famous wine country and a historical city in P. R. China. Insuring the continuity of urban context is an effective method for creating a distinctive image of a city. Considering the authenticity, sustainable development, enforceability and regional differences of urban contexts, it is an appropriate way to extract the original urban context and adopt a proper design method that combines humanized nature, material culture, and intangible culture to form an area with cultural atmosphere on both banks of the Tuojiang River. 相似文献
205.
A numerical simulation method, the node method, and single, multi-triangle progression were used to analyze the shore stress field of vacuum plate glass. By optimizing the shore distribution, the points of greatest and least stress in vacuum plate glass were determined. The distributions of greatest stress in vacuum plate glass were calculated using MATLAB. These calculations can provide numerical foundations for accurately analyzing the shore stress and flexibility of vacuum plate glass. The result shows that the greatest stress exists in the end surface of every shore, and the maximal stress is in the second shore at four-square sides, then follows the shore of next row. The theoretical calculations correspond to the software analysis results. 相似文献
206.
A new apparatus was constructed to investigate the impact of various loading conditions on the permeability of coal specimens. Test results show that loading condition has a definite influence on the permeability of coal specimens. Higher pressures lead to lower permeability, and it seems that the confining pressure has a greater effect than the axial stress does, while the permeability is related exponentially to applied stresses. Based on the experimental results, an equation governing gas seeping through coal seams is deduced within the frame of Darcys Law, which may be helpful to understand the permeability properties of stressed coal seams and to improve the drainage of gassy coal beds. 相似文献
207.
Numerical simulation of the flow and temperature fields in an automotive exhaust muffler 总被引:2,自引:0,他引:2
By building a model of a typical exhaust muffler structure, a grid mesh was formed based on the calculation characteristic of the flow field. The software ANSYS CFX then was used to numerically simulate the flow and temperature fields in a muffler. The effects of the gas velocity and temperature variation on sound elimination performance, including the acoustics and aerodynamics performance, were analyzed. The result suggests that high velocity turbulence and high speed flow should be eliminated from muffler structures when designed. At the same time, to provide satisfactory noise elimination, pressure loss should be reduced as far as possible. The pressure loss can be decreased when reducing the perforation structure. 相似文献
208.
Based on structural deformation analysis, we developed calculation models of externally prestressing tendon stresses increments for simply supported beams on service loads. The Windows program SICPEM for calculating stress increments, based on energy principle, was programmed using the object oriented method. Six beams results, tested by Tan, and the free length of externally straight tendons were recomputed by the program. The ratio of computed results to test results is 0.895, and the standard deviation is 0.013. Furthermore, the free length of externally straight tendons, for which the second order effect can be ignored safely, is ten times beam depth. This coincides with the reference literature. 相似文献
209.
A forecasting model for logistics demand was presented to overcome the limitations of single goal forecasts of logistics demand and forecast data complexity. Based on the forecasting evaluation index and pretreatment of rough set theory, a multi input and multi output wavelet network (MMWNN) model for forecasting multi element regional logistics demand was studied. The network configuration was confirmed using the stepwise checkout and iterative gradient descent methods. After rough set reduction, the evaluation index was used to forecast the multi element regional logistics demand. The results of the numerical example indicate the feasibility and effectiveness of the model. 相似文献
210.
The temperature distribution and thermal stress distribution of brake discs under emergency braking conditions were studied using the finite element method (FEM). The discs were of three types: those made of functionally graded SiCp/Zl104 composite materials, of uniform (20% volume) SiCp/Zl104 composite materials, and of compacted graphite iron, respectively. The rule of mixtures of dual phase material and the discretization of the material composition distribution were applied to estimate the material properties of functionally graded composite materials. The results show that the temperature and thermal stress of brake discs made of graded SiCp/Zl104 composite are the lowest among the three types studied, and the distribution of temperature and thermal stress of this brake disc type is more uniform than the others. Furthermore, brake discs made of functionally graded SiCp/Zl104 composite can reduce vehicle weight and increase wear resistance capacity. The results provide a theoretical foundation for fabricating brake discs made of graded SiCp/Al composite material. 相似文献