18 April 2011, Volume 29 Issue 11-11
    

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  • Abstract ( ) Download PDF ( ) HTML   Knowledge map   Save
    In this paper, the heat storage and release properties of an active phase-change thermal storage device have been tested under different working voltage and exhaust heat temperature. The experimental results show that: different working voltage and exhaust heat temperature make great difference on the time and efficiency of thermal storage/release. Under higher voltage and exhaust heat temperature, the time that the device needs to store heat is short. The increased working voltage can enlarge the temperature difference between the hot and cold sides of semiconductor chips, and then reduce the heating coefficient. Compared to passive phase-change thermal storage devices, the biggest advantage of the device is the adjustability of working voltage. Therefore, much higher heat storage/release properties can be assured by adjusting working voltage within a reasonable range. At the same time, the device overcame the mismatch of thermal energy supply and demand sides on time, place and intensity in the process of recycling low-temperature waste heat, which cannot be improved by passive phase-change thermal storage devices.
  • You-Xing YANG
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    On the basis of the thin section observation, scanning electron microscopy analysis, and comprehensive analysis involving reservoir pressure coefficient, porosity type and size, throat features, and other characteristics of the data, it is found that the study area, Hutubihe Formation's lithologic reservoir is a Class I reservoir, and the reservoir possesses main characteristics, such as high porosity, high permeability, low displacement pressure, and a large throat. Compaction of the sandstone reservoir in the study area is from moderate-weak intensive. It is obtained from final study that although the content of the low degree maturity and the relatively poor ability plastic cuttings are higher, but the high-quality reservoirs are still able to form in the study area, the reason for that is mainly due to extensive development of high-energy micro-braided channel deposit, the mud content of high-energy micro-braided channel is lower, therefore the porosity and permeability is higher; the size of sand in the study area is mainly the lithic sandstone and fine particles, the larger particle size enhances the compressive strength of sandstone; the diagenesis is slow down because of the low geothermal gradient in the study area; the early hydrocarbon charging enhances the real capacity of the reservoir under the pressure, so that the original porosity can be preserved well; in the later stage, the structure in the study area is stable, big fault activities that do damage to oil and gas reservoir never happen, and the primary pores are not destroyed.
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    To study the palaeogene growth and development, and distribution characteristics of sequence stratigraphic bed in Chepaizi area, the sequence stratigraphy is used with a discussion of its principle, method and technology. Based on composite analyses of seismic, drilling, well logging and outcrop data, together with interwell and log-seismic correlations, the palaeogene sequence stratigraphic classification and features are obtained with two third-scale sequences and four system tracts identified. It is shown that the structure of this area assumes a large-scale slope with a small distinct slope break, with the development of a tract of Lowstand systems under the slope break. The tract of Lowstand systems and that of Transgressive systems are divided by first flooding surface. The tract of Highstand systems is undergrown or not identified. From the tract of Lowstand systems develop diffluent rivers of fan delta and barfacies of beach. From the tract of Transgressive systems develop mudstone and siltstone in beach barfacies. Stratigraphic development is controlled by sediment sources, relic landform, climatic conditions and lake level changes. The sequence stratigraphic framework of palaeogene in Chepaizi area is established. Under the sequence stratigraphic framework, favorable sectors of oil and gas bearing are predicted in studied area, which would play an important role in the search of lithologic subtle reservoirs in northwestern margin of Jungger Basin.
  • Kai LIU
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    There are two different frequencies corresponding to the same distance caused by the randomness of observation time, based on the analysis on the different frequency of sawtooth frequency modulated continuous wave ranging system. By means of analysis on the difference frequency signal in time domain and frequency domain, it is found that this kind of ranging ambiguity can be settled by mixing frequency twice. The output frequency of the signal processing unit corresponds with the distance one to one at any observational time. The effectiveness of this signal processing method is verified by the signal spectrum and time-frequency curves emulation using the simulation software.
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    It is necessary to ensure the maneuver across the Yangtze River by floating bridge constructed by portable steel bridges and civilian ships. A comprehensive consideration should be invloved in the scheme of the bridge raft, including a variety of technical factors and uncertainties. The optimization of the scheme is related with the factors such as constructing time, equipment and man power. Based on the calculation results of bridge rafts, an evaluating system is built, with consideration of spacing between interior bays, raft length, number of trusses, easiness of operation and the maximal bending stress. A fuzzy matter element model of optimizing the selection of bridge rafts is built by combining quantitative analysis with qualitative analysis. The sequence of schemes and the optimization result are obtained finally based on Euclidean Closeness degree. The application result shows that the method is simple and practical.
  • Abstract ( ) Download PDF ( ) HTML   Knowledge map   Save
    Causes and sites of several fires occurred in a bar, the Dancer King Club in Shenzhen City, and the Forever-joy Latin Club in Fujian Province are similar. Heavy casualties caused by fire in the short time. Therefore, it is worthwhile to study fire prevention and control measures. The advantage of the FDS software is taken to construct a fire model of the bar. The evacuation simulation parameter can be rationally set through the rational analysis involving on site situation of persons. By setting the appropriate fire scene according to the actual fires, the software can analyze the parameter change of the heat radiation, smoke temperature, smoke toxicity, and smoke visibility in order to figure out the available evacuation time. Combined with CFE software to simulate the evacuation process, fire consequence analysis has been carried out in accordance with the different fuel types, fire facilities, and the number of evacuated persons. Fuel analysis results show that renovation of polyurethane foam sound-absorbing cotton weakens fire technology and is direct cause of the fire spreading speed. The materials can produce large amounts of toxic smoke and cause casualties in a short period. The simulation results of different fire-fighting facilities reflect the important role played by automatic fire-fighting facilities. The quick response sprinkler heads should be promoted for the sprinkler system in public amenities. The reason for large number of casualties is that automatic fire-fighting facilities not been installed in accordance with national standards. The quantitative analysis of the anticipated casualties in the different number of evacuated persons has proved that the fixed member of fire control manager in the public amenities has a great significant. The results can be used to analyze the causes of fires and fire prevention measures.
  • Abstract ( ) Download PDF ( ) HTML   Knowledge map   Save
    Hongtoushan Mine is one of the deepest metal mine in China, with very good resource potential. Most studies of this mine were based on two-dimensional modeling. In this paper, a Hongtoushan Mine geological database is first built, the earth surface 3D model, the fault 3D model, the body 3D model and the stratum 3D model are then built based on 3D geological modelling and the international 3D deposit software Surpac according to the geological features of this mine. In order to extract the ore-controlling factors, some 3D spatial field models are built, including the lithology 3D field model, the fault 3D field model, the mineralization distribution model and the geophysical index 3D spatial field models such as CSAMT model and TEM model after geological spatial divisions into unit blocks. Those models can visually display the spatial distribution of the geological body, as a foundation for further stereo quantitative prospecting prediction in deep and marginal parts of Hongtoushan Mine. The obvious advantage of 3D geological modelling is shown in stereo quantitative prediction of concealed ore body, and it is of a high value in practical applications.
  • Abstract ( ) Download PDF ( ) HTML   Knowledge map   Save
    In order to study the mechanical deformation characteristic of soil mass and wholly grouted cable under the pull-out condition, a numerical calculation model is founded by FLAC3D, the mechanical characteristic of cable, response of soil mass, and influence factors for pull-out characteristic are analyzed. The analysis results show that: (1) the axial stress of cable reduces along shaft; (2) during the loading procedure, the failure propagates rapidly along cable shaft, and eventually leads to the whole failure of cable; (3) the soil mass tends to be pulled out by cable with the friction force between cable and soil mass; (4) with the increase of surrounding stress, the curve of loading-displacement before failure phase displays even more obviously linear characteristic, meanwhile the failure load of cable becomes larger and larger, and the entire relationship between failure load of cable and surrounding stress can be fitted by the exponential equation with high precision; (5) the increase of surrounding stress can lead to the increase of cohesion between cable and surrounding soil mass, however with a limited magnitude; therefore when surrounding stress increases to some degree, the anchor force of cable can not be increased anymore.
  • xiao-yu zhao
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    With Monte Carlo simulation method, the aging phenomenon of the two-dimensional XY model is numerically studied. Starting from an ordered state, the system is suddenly quenched to critical temperature Tc. By measuring the two-time autocorrelation function A(t,t’) we confirm the aging phenomena. Especially, the form of dynamic scaling of A(t,t’) is more creditable than ancient literatures.
  • . 2011, 29(11-11): 59-61.
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    The autonomous parking system is an intelligent technology to park a car into a small space. Based on Ackermann steering geometry, considering the parking practice, the minimum parking space and the bound of start point and collision-free space are obtained. Then based on Bezier curve, considering the dynamic constraint condition and the parametric equations, the dynamic relationship between x and y is established. For each time point t, followed by a specific steering angle and turning radius, a new location can be obtained. So a car can be controlled to move along a Bezier curve, and finally the continuous path is generated. At last, the simulation based on Matlab shows that the car can not only avoid the obstacles effectively, but also move smoothly on turning points. So the continuous auto-parking can be realized in a space as small as possible.
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    To investigate the air quality in Chancheng area, Foshan City, the monitoring data were analyzed, which shows that after the emission control of industrial pollution, the air quality is improved. The pollutants from thermal power enterprises are reduced, but still with a high emission proportion in Chancheng area. To study the emission reduction of thermal power enterprises and to show the impact of pollutants on the environment, ADMS-Urban and ArcGIS are used to simulate the dispersal of pollutants from thermal power enterprises and the effect of emission reduction is evaluated under some unfavorable weather conditions. The further room for pollutant reduction is discussed. It is shown that pollutants of Funeng Power Plant are reduced, but with quite a room for further reduction. The increases of the power plant stack height, the diameter of the chimney and the proportion of clean fuels in power plant fuels are just a few of possible measures. The great potential exists in improving the fuel quality.
  • Reviews
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    Diesel engine using lean-burn technology is arisen due to the big push driving from energy saving and exhaust reduction policy. The researches on the main diesel emission (PM and NOx) for fuel properties, new engine technologies, and after-treatment technologies are reviewed. As for air handing, the pressure ratio, layout of turbocharger and assembled turbochargers as well as the effect of combustion parameters on the new conception combustion and emission are described. The variable geometry turbocharger, the two-stage turbocharger, and electric turbocharger are the main technologies to content with the more stringent emission regulations. The combustion parameters are compress ratio, the EGR ratio, and the diameter of injector, etc. In order to improve the new combustion, it is necessary to develop the combustion model and simulation by using CFD. At the same time, the impact of injection strategies on emission reduction and the difference of low and high pressure EGR are presented. The main injection strategies include the multiple injection of the common rail injection system. Moreover, it is essential to improve the injection ratio and increase the injection pressure up to a high lever. It is a main technology to reduce the in-cylinder NOx emission. Compared with the high level EGR ratio, the medium level is the better solution for in-cylinder pollution control. NOx control is centered on Selective Catalytic Reduction (SCR) and NOx Storage Reduction (NSR) for diverse applications. The focus is on the V/W/Ti and zeolite catalysts for SCR technology. As for NSR technology, a typical NSR catalyst formulation contains basic NOx storage components (mostly barium species), Noble Metals (NM), such as Pt, Rh, Pd, and support oxides. Diesel Particulate Filter (DPF) technology is very effective for the PM control. Improved DPF substrate and new DPF regeneration strategies are described. Finally an update on Diesel Oxidation Catalysts (DOC) is provided to show the potential solutions for HC and CO emissions.
  • . 2011, 29(11-11): 76-79.
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    Aimed at the design of distribution layer in defense works, the status and problems involving distribution research were summarized and analyzed. The perfect distribution layer should be safe, economical, practicable, and reliable, and have enough static compressive strength and good resistance to the impact, which should weaken the stress wave strength and absorb the energy deriving from explosion to the greatest extent under the condition of repeated impact loadings. And some issues that need to be resolved and the development tendency in the design of distribution layer were discussed. The results show that the main materials in the distribution layer are still concrete or soil at the present stage and days to come, and the perfect structure should be the combination of layered structure and cavities-contained structure. All those could give a reference to the design of advanced distribution layer in defense works.