18 May 2011, Volume 29 Issue 14
    

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    Articles
  • CHEN Tao;ZENG Qingxuan;FENG Changgen;LI Mingyu
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    The decoloration of the erythromycin broth by the polypropylene anion exchange fiber is studied in this paper, including the effects of contact time and pH value on decoloration characteristics. The results show that the polypropylene anion exchange fiber is better than the ion-exchange resin, with advantages such as higher exchange and rebirth speed. When the ambient temperature is 301K, the decoloration is fast, and the decoloration rate reaches 85.3% in 30 minutes, and the lose rate of erythromycin is 1.17% in a static test. The potency and the quality of the erythromycin product are improved through the dynamic decoloration by the ion-exchange fiber.
  • DING Wenchuan;ZHU Qingxiang;ZENG Xiaolan;WU Dan;TIAN Xiumei
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    Biochar from biomass pyrolysis has received much attention recently due to its strong affinity for organic pollutants and heavy metals. Previous studies have revealed potential applications of biochar in the contaminated soil remediation. However, the knowledge of pyrolysis temperature effects on biochar as a soil amendment remains lacking. In this paper, three biochars produced at 300℃, 500℃ and 700℃ were added into Lead (Pb) and Cadmium (Cd) contained soil, variations of these two metals were analyzed before and after 60 days incubation. The results show that soil pH value is increased by 0.35—0.86 units after biochars addition and incubation. Acid extractable form contents of Pb and Cd are reduced, whereas the residual form contents are increased. The reducing bio-availability of target heavy metals by different biochar amendments is in the following order: 700℃>500℃>300℃. With the same amount of biochar addition, Pb residual form contents in the combined polluted soil are increased by 50.60%—72.79% from the single polluted soil, and Cd acid extractable form contents in the combined polluted soil are increased by 7.53%—12.99% from the single polluted soil. Pyrolytic temperature affects characteristics of biochar surface structure and mechanism of heavy metal sorption on biochar, and then affects the states of lead and Cadmium in soils.
  • QIN Shiyin;WEI Xiaoming;LIU Yuanmin;MAN Yiyun
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    In view of blurred remote sensing images with the noise resulted in some degradations during imaging and transmission processes, a kind of restoration method is proposed based on MTF estimation and total variation optimization. The restoration principle of blurred remote sensing images with noise is elucidated in depth through a thorough analysis of frequency characteristics of MTF. In order to deal with the noise, a new piecewise approximation strategy for MTF estimation is employed, which has the general applicability and outperforms the conventional models in overcoming noise disturbance by experiment demonstrations. Moreover, aiming at the restoration processing of blurred remote sensing images with noise, an improved method of fast total variation optimization is adopted to achieve the optimal restoration effect. A series of experimental results indicate that proposed restoration method could preserve more details and texture information of images besides its satisfactory performance of eliminating noise, thus it could provide an effective approach to the restoration processing of remote sensing images with heavy noise.
  • PENG Yan;LI Xinqing
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    The secondary forest, as an integral part of Karst forest ecosystem, may be the future of a forest. The soil organic carbon is an important part of the soil organic matter and its content has a major impact on soil biological activities and is also an important indicator of the soil fertility. To understand the effects of soil organic carbon on soil biological activities, three sample plots are taken, including a shrub, a Ligustrum lucidum forest and a pine forest and they are compared with the tilled field in the suburbs of Guiyang City during the sampling time (June, 2008-May, 2009). The data show that the shrub is characterized by low substrate carbon utilization, weak biochemical processes and less available nutrients of plants and microbes based on per gram soil organic carbon, although with the highest soil organic carbon among the sample plots. The Ligustrum lucidum forest is marked by high nitrogen cycle rate, rich in denitrification enzyme and serious gaseous nitrogen loss, while, the pine forest is characterized by high decomposition speed and strength, high soil microbial and enzyme activities, strong soil biochemical processes and low gaseous nitrogen loss based on per gram soil organic carbon. Generaly speaking, the organic carbon content limits the size of soil microbial communities, affects soil enzyme activities in shurbs, influences the microbial nitrogen conversion rate and organic matter decomposition rate indirectly but has no significant effects on denitrification in the study area. Therefore, the most appropriate way to the remediation of degraded desertification soil is to allow the natural plant communities to develop in order to improve site conditions in the early stage of the soil remediation and then to select appropriate tree species with the mixed model of coniferous-broadleaved species.
  • LI Zijun;DENG Yanxing;SHU Aixia
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    Based on the current knowledge of sulfide ores, an orthogonal experiment design is made to conduct experiments on the sulfide ore samples obtained from a certain mine. An orthogonal array with four factors and three levels is adopted. The importance of factors that affect the caking of sulfide ores is determined through a direct analysis on range. It is shown that different factors have diverse effects on the caking degree. The caking state of the sulfide ores can be significantly changed by changing these factors. The influences of different factors on caking are in the following order: temperature > water content > humidity > particle size. According to the trend analysis, the variation of the caking ratio against each factor is obtained. On the basis of orthogonal experiments, single factor experiments are carried out to further qualitatively analyze the relations between temperature, humidity, water content, particle size and caking ratio. Finally fitting curves of these factors versus caking ratio are obtained. The feasibility of orthogonal experiments is confirmed. Single factor experiments demonstrate that the temperature, humidity, water content, particle size are closely related with the caking of sulfide ores.
  • CAO Lanzhu;YANG Xiu
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    3# line Changsheng dump of Yuanbaoshan is a typical loess base dump, before it is employed, the dump slope stability must be evaluated. The formation of the dump is not instantaneous, but is slowly filling up. For the operating process of comprehensive dumping machines, a rigid body limit equilibrium method of different high slope dump is used to calculation slope stability. And FLAC 3D is adopted to simulate the deformation of the dump slope. The numerical simulation studies the impact of the basement and groundwater unsteady factors on the slope stability, reveals the rock slope deformation and land slide displacement law model, conducts a scientific evaluation of slope stability, and provides a reliable basis for the safety of the mine production.
  • ZHANG Yingzhi;TENG Jiafeng;WANG Yanyong;PENG Huijun
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    Low porosity, low permeability, presence of a starting pressure and development of micro-fractures are the main characteristics of ultra-low permeability reservoirs, and the conventional production decline law and the water drive characteristic curves can not correctly reflect their production features. Based on the seepage theory, combined with production data, a production decline law and water drive characteristic curves in ultra-low permeability reservoirs are obtained. It is shown that in the analysis of the production decline, water cut and water drive characteristic curves, the effect of the starting pressure must be considered. The production decline of an ultra-low permeability reservoir experiences two stages, and using two decline curves to fit the production data can achieve better results. In the analysis of the water drive characteristic curves, recovering the water cut of high water cut wells can reveal the real water cut level of the reservoir, and the ultimate recovery can be predicted more accurately. This paper can provide some guidelines for the tapping potential measures and modification for the ultra-low permeability reservoir.
  • LIU Shousheng;WANG Zhong;ZHANG Lu
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    In this paper, an intuitionistic fuzzy C-means clustering algorithms (IFCM) based on genetic algorithms is proposed. Compared with other methods based on various similarity matrixs, more objective results can be obtained by utilizing the optimal method to do clustering analysis. Firstly, the IFCM clustering method currently in use is discussed. By using this method, a local optimal value may be obtained as fuzzy C-means. The method proposed in this paper can overcome this drawback by combining that method with the GA method. In this process, the main problem is that the real number is changed into the intuitionistic fuzzy number. As a result, the clustering center is also changed from a real number to an intuitionistic fuzzy number. There may be some difficulty in handling with each clustering center, because the sum of membership, non-membership and uncertainty must be considered for each intuitionistic fuzzy number. In the GA program, after the cross operation, normalization is done for each clustering center to get the ideal results. At the end of this paper, an example is given and three methods are compared to illustrate the effectiveness of this method.
  • LUO Jingfeng;XU Kaili
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    The reliability evaluation of the distribution system becomes more and more important due to the customer's requirement for a distribution system of a higher quality. Based on the analysis of reliability for distribution systems, a variable fuzzy method is proposed. Firstly the matrix of relative membership degree is calculated based on the index feature value, the matrix of index evaluation interval, the matrix of variable range evaluation interval and the matrix of point values. Then the comprehensive relative membership degree of samples is calculated by a model of variable fuzzy evaluation. The rank feature value is thus obtained, for the evaluation. The variable fuzzy engineering method can scientifically determine the relative membership degrees of sample's indexes at level intervals, and reasonably determine the evaluation level of each sample by varying the model and its parameters. From the evaluation of the reliability of the distribution system, a relative stable value can be obtained to be regarded as the final evaluation. The case study shows that the method gives more reliable evaluation of reliability of a distribution system than the method in literature.
  • WANG Xiao;
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    In view of the shortcomings of the current simulation systems in fidelity and real-time capability, and the lack of data for generating a digital terrain model, the construction drawing is used for a data source, with Auto CAD to be used for modeling. By a data conversion module of polytrans, the data in the standard format are obtained. Then, the solid model is imported into Creator/Vega to do the texture paste and scene synthesis for the simulation system. In the process, the landscape design scheme can be customized and changed, and a secondary development platform can be used to extend the applications of the data analysis module. The overall framework of the virtual simulation system based on AutoCAD and Creator/Vega is thus constructed. The application scopes of four terrain conversion algorithms are analyzed. The traditional information of design files, such as floor plan, longitudinal section and cross section, is extracted and used in the three-dimensional modeling of the main road. At last, the real-time simulation is achieved. Simulation results are realistic, and can be adjusted in real time.
  • Reviews
  • ZHENG Mingbo;QIU Danfeng;PANG Huan;PAN Lijia;PU Lin;SHI Yi;ZHENG Youdou
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    Lithium-air batteries, based on the reaction of lithium with oxygen from air, have very high theoretical specific capacity of 3828 mAh/g and have important potential applications for electric vehicles. This paper reviews the new progress of studies of lithium-air batteries. The structure and operation mechanism of the aprotic system, hybrid aprotic-aqueous system, and solid state system are analyzed. The air electrode, catalyst, and electrolyte of the aprotic system are discussed in detail. The pore volume of the porous carbon is an important structural parameter for the specific capacity of the air electrode. The porous carbon with a large pore volume would possess a high specific capacity because it can provide a large space for lithium oxides formed during the dicharge process. The specific surface area and the average pore size of the porous carbon also affect the specific capacity. Appropriate catalysts can effectively reduce the overpotentials for the oxygen reduction reaction and the oxygen evolution reaction, and consequently, increase the energy efficiency of the battery. The electrolyte with high polarity, low viscosity, low moisture adsorption, and high oxygen solubility is preferable for the performance of the battery. The separator and the electrolyte of the hybrid aprotic-aqueous system are also discussed. The lithium super-ionic conductor glass film with good stability in both aprotic and aqueous electrolyte is very important for the hybrid aprotic-aqueous system. The recent development of the solid state system is commented, including the development direction of this field.
  • MA Xianfa;ZHANG Jizhou;SONG Fengbin
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    The study on the mechanism of plant salt- tolerance has the important significance to improve and utilizes of saline soil, and to cultivate and breed new varieties of salt-tolerant plants. According to the published studies on plant salt-tolerance, plants show a range of physiological and ecological adaptation, including selectively absorbing inorganic ions, regulating K+/Na+ ratio to lower osmotic pressure in vivo; salt stress increases the antioxidant enzyme activity, slows down the damage of reactive oxygen species; hormone can induce some of the important gene expression in salt-tolerance signaling pathways; Some halophytes photosynthetic pathway changes could help improving their ability for adapting saline habitats; saline environment promotes that environment-related proteins are highly expressed in vivo for salt-tolerant plants; and some morphological changes in the structure of plants occur, through salt excretion, salt separation, and salt rejection, the plants adapt the salt environment. Thus, physiological ecology adaptation of plant salt-tolerant is regulated and controlled by many aspects.