[an error occurred while processing this directive]

Table of Content

    20 November 2016, Volume 52 Issue 6
    Investigation on Aerodynamic Characteristics of Long-Grouped High Speed Train Subjected to Crosswind
    SHANG Keming, DU Jian, SUN Zhenxu
    2016, 52(6):  977-984.  DOI: 10.13209/j.0479-8023.2015.137
    Asbtract ( )   HTML   PDF (822KB) ( )  
    Related Articles | Metrics

    RANS approach is adopted to perform an investigation on aerodynamic characteristics of high speed trains in crosswind conditions. Both the flow structures and aerodynamic loads are analyzed in detail. Results reveal that abundant flow phenomena could be observed on the streamlined head and affected by the yaw angles of the incoming flow. Detached vortices can be found on the leeward side of train, which origin from the bottom of the streamlined head and develop along the train body and gets far away from the train body. The first car of the whole train owns the worst aerodynamic circumstance. As the yaw angle grows, the side force and the overturning moment of the first car gradually grow bigger, and the running circumstance of the train becomes worse.

    Geographical Information Extraction from Instant Communication Messages: A Case Study of WeChat
    ZHANG Ruijie, TIAN Yuan, LIU Siye, WANG Wenfu
    2016, 52(6):  985-989.  DOI: 10.13209/j.0479-8023.2015.136
    Asbtract ( )   HTML   PDF (1668KB) ( )  
    Related Articles | Metrics

    In order to provide synchronous map service based on message semantics in instant communication software, this paper proposes a technical solution, basically a comprehensive combination of Chinese text segmentation, pattern recognition, and image-text integrated service. A case study based on actual WeChat communication messages is carried out to verify the technical solution, which shows that the proposed solution is both feasible and practically effective. The synchronous message semantics-based image-text integrated service provided by the case study improves the user experience very well.

    Feature Description Method in Dense Matching of UAV Video Images
    WEI Yunpeng, ZHAO Hongying, XIN Tiantian, ZHENG Hongyun
    2016, 52(6):  990-998.  DOI: 10.13209/j.0479-8023.2016.063
    Asbtract ( )   HTML   PDF (1191KB) ( )  
    Related Articles | Metrics

    In order to reduce the time consumption of UAV video image dense matching, and improve processing efficiency, this paper presents a fast feature description and feature matching method. The method uses Harris operator to detect corners, adopts feature descriptor S-DASIY (DASIY) to characterize detected corners and generate the 25-dimensional feature descriptor for the corners. The feature points of the images are matched in accordance with the appropriate matching criteria, to get the match points between images. Experimental results show that the proposed fast feature description and feature matching method can significantly reduce the time of generating and matching feature points.

    Design of a Humidified Nephelometer System with High Time Resolution
    LIU Hongjian, ZHAO Chunsheng
    2016, 52(6):  999-1004.  DOI: 10.13209/j.0479-8023.2016.053
    Asbtract ( )   HTML   PDF (1533KB) ( )  
    Related Articles | Metrics

    In order to study the diurnal variations of aerosol hygroscopic properties in North China, a new humidified nephelometer system is designed with the advantage of high time resolution and high humidification efficiency. In this system, two water baths are used for the first time to control humidification process in turn, reducing the circulation cycle from two to three hours to about one hour. Besides the nephelometer lamp power is reduced from 75 W to 25 W, and a piece of heat mirror is set ahead of the lamp. After those modifications, the temperature rising inside the chamber decreases from 4.3 ºC to 2.3 ºC and humidification efficiency rises. The original RH sensor inside the chamber is inaccurate, so two Vaisala sensors are set at the inlet and outlet of the nephelometer to correct the RH inside the chamber. In the future, this humidified nephelometer system will be used in in situ measurement in North China to get the diurnal variation properties of aerosol light scattering enhancement factor.

    Velocity and Effective Anisotropic Parameter Analysis Using Nonhyperbolic Traveltime Based on Deterministic Trace Resorting Method
    REN Yan, LIU Zhipeng, LI Shilin
    2016, 52(6):  1005-1013.  DOI: 10.13209/j.0479-8023.2016.046
    Asbtract ( )   HTML   PDF (1710KB) ( )  
    Related Articles | Metrics

    The lower lateral spectral resolution is caused by the divergence of energy clots in the velocity and effective anisotropic parameter spectra when standard semblance operator is used. To solve the problem, the deterministic trace resorting differential semblance operator is introduced. By resorting the seismic traces, the differential semblance operator is sensitive to the moveout between the adjacent seismic traces, which maximize the spectral resolution. This method could be firstly applied to effective anisotropic parameter analysis using nonhyperbolic traveltime. The synthetic and field data examples are introduced to testify the efficiency of the new method, and the results confirm that spectral resolution increases a lot compared with standard semblance method.

    Finite-Frequency Effects of SS Precursor
    GONG Jianhua, GE Zengxi
    2016, 52(6):  1014-1024.  DOI: 10.13209/j.0479-8023.2016.049
    Asbtract ( )   HTML   PDF (1719KB) ( )  
    Related Articles | Metrics

    First, SS precursor boundary sensitivity kernel is calculated based on finite-frequency theory and the sensitivity of SS precursor traveltime perturbation to the topography perturbation implemented on mantle discontinuity is analysed. Next, SS precursor waveform with topography perturbation implemented on mantle discontinuity is simulated using SPECFEM and its traveltime perturbation is measured and compared with the traveltime perturbation predicted by finite-frequency theory. It is found that finite-frequency theory can well explain the wavefront healing effect of SS precursor. At last, an inversion scheme is built based on boundary sensitivity kernel, and more reliable topography of the mantle discontinuity can be obtained after considering the finite-frequency effect of SS precursor. This research provides some preliminary knowledge for inversion of the topography of mantle discontinuities using SS precursor.

    Evaluation on Stress Sensibility of Low Reservoir in Situ Conditions
    SHENG Yingshuai, HU Qingxiong, GAO Hui, SHI Yongmin, DANG Yongchao, SHAO Fei, DU Shuheng, FANG Yuanyuan
    2016, 52(6):  1025-1033.  DOI: 10.13209/j.0479-8023.2016.050
    Asbtract ( )   HTML   PDF (4882KB) ( )  
    Related Articles | Metrics

    In order to study the effect of confining press and pore press on permeability, the new method of evaluation on stress sensibility is proposed. Three pieces of low permeable reservoir rock samples in Songliao Basin are selected. A servo-controlled triaxial rock mechanics test system is employed to investigate the permeability of sandstone samples under conventional conditions and in situ conditions. The results show that: 1) The permeability of three pieces of samples reduce with confining press increasing and pore press reducing. 2) The denser the rock is, the stronger stress sensitivity is, in situ conditions, which explains the mechanism of low permeability reservoir sensitivity differences by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), constant speed mercury injection experiment. What’s more, throat size and shape, plastic mineral content and type contribute to the differences of permeability sensitivity. 3) Mineral content and type of plastic are the major factor of the sensitivity of permeability differences. The stress sensitivity of tight reservoir permeability rock becomes strong with the increasement of mica, clay and other plastic mineral content. In the practical work, evaluation on stress sensitivity of permeability, the effect of confining pressure single factor is mostly considered, butthe effect pore presss would be ignored, which is bound to bring larger human error. So evaluation on stress sensibility in situ conditions is essential, which is significant for further understanding of stress sensitivity of low permeability reservoir characteristics and development.

    Revelation on Remaining Oil Excavation from Stress Interlayer Division in Special Low Permeability Reservoir: Take Yanchang Formation of Baiyushan Reservoir in Ordos Basin as an Example
    JIN Wenqi, DU Shuheng, LU Xiangwei, WU Zhiyu, SHI Yongmin
    2016, 52(6):  1034-1040.  DOI: 10.13209/j.0479-8023.2016.097
    Asbtract ( )   HTML   PDF (2215KB) ( )  
    Related Articles | Metrics

    As to Chang 4+5 formation of special low-permeability Baiyushan reservoir in Ordos Basin reservoir, the hydraulic fracture distribution is not regular and difficult to predict. The method of traditional engineering geology and special logging, conventional well logging, micro facies research were combined. Through the stablishment of three-dimensional rock mass mechanics model of reservoir, the full length fracturing numerical simulation was carried out with the change of stress field. More accurate geometry parameters of fractures were got, stress interlayer insulation could be regarded as a kind of new development of geological property which would play an important role in fracture extension, then the development adjustment measures are put forward. The conclusion would provide an important scientific basis on decision-making efficiency in low permeability reservoir development and improve the residual oil recovery degree.

    Study on Globe Spatial Grid Reference System Construction
    CHENG Chengqi, WU Feilong, WANG Rong, QIN Yonggang, TONG Xiaochong, CHEN Bo
    2016, 52(6):  1041-1049.  DOI: 10.13209/j.0479-8023.2016.051
    Asbtract ( )   HTML   PDF (1724KB) ( )  
    Related Articles | Metrics

    To supplement the deficiency of the latitude and longitude existed as location code, such as complex description, non-regional characteristics and complex computation, a globe spatial grid reference system is constructed based on GeoSOT from Peking University. The grid system, built from a perfect quadtree with one degree, one minute and one second grid, could be fit for air-earth joint action. It designs a simple and practical location coding method, which also supports distance simple calculation. It could realize multi-source spatial data integrated retrieval, and develop methods of efficient code operation, framework of spatial computing, and 3D-earth grid system. Globe Spatial Grid Reference System will definitely play an important role in the future of big spatial data applications.

    Recovery of Trace Uranium in Organic Waste Liquid
    GUO Yitian, CHEN Qingde, SHEN Xinghai, ZOU Lexi, LI Yingqiu
    2016, 52(6):  1050-1056.  DOI: 10.13209/j.0479-8023.2016.117
    Asbtract ( )   HTML   PDF (607KB) ( )  
    Related Articles | Metrics

    Considering the difficulty to recover trace uranium in organic phase, Na2CO3 aqueous solution was used to strip uranium, then the amidoxime adsorbents were chosen to enrich uranyl in the aqueous phase. In the stripping part, the kinetics of stripping, the effects of the concentration of Na2CO3 and phase ratio on the stripping efficiency were investigated. Then, in the adsorption part, the effects of shaking rate, the mass of adsorbents and the concentration of Na2CO3 were studied. After the validation of the recyclable performance of the amidoxime adsorbents, a process for recovering trace uranium in organic waste liquid was proposed.

    Type Classification of Rural Settlements and Its Consolidation Models Based on the Coupling of System Factor Characteristics
    QU Yanbo, JIANG Guanghui, SHANG Ran, GAO Yu
    2016, 52(6):  1057-1067.  DOI: 10.13209/j.0479-8023.2016.038
    Asbtract ( )   HTML   PDF (1789KB) ( )  
    Related Articles | Metrics

    Based on the theory of man-land relationship area system, following the research ideas, which were factors to express the feature and features to group the type and types to guide the models and models to improve factors, the social economic factors and natural environment factors of rural settlement were defined clearly. The characteristics of the inequality of rural industry-labor structure, the livability of rural living environment and the intensity of rural residential land were analyzed quantitatively by the coordination coefficient model and multifactor comprehensive evaluation method. Qualitative coupling method of elements and characteristics were used to classify the rural settlements as eight types in the same county, and eleven rural residential consolidation models were proposed from the three aspects of resources allocation, structure optimization and space reconstruction in the light of the limiting factors of different rural settlement type. The empirical results show that the difference is significant in the aspect of rural settlements elements and regional characteristics in Pinggu district, Beijing. There are more restrictive factors for rural residential area sustainable utilization. 55.64% villages are imbalance in the aspect of industry-labor structure, 52% villages are unfavorable relatively in the aspect of housing conditions, 44.36% villages are less intensive in the aspect of land use, and the formation of the imbalance-not livable-height intensity is too much in the whole region. Single factor special consolidation and multi-factor comprehensive consolidation, which include upgrading of rural industrial structure, transferring of surplus labor force, renewal and reorganization of rural living environment factors, reconstruction of the urban and rural system and spatial agglomeration, are the core contents of rural residential land consolidation and rich and beautiful countryside construction.

    Ecological Optimization of Land Spatial Pattern Based on the Reconstructions: Take the Reconstructions of Lushan, Sichuan for Example
    CHAI Huixia, RAO Sheng, MOU Xuejie, HUANG Qi, WANG Ruibo
    2016, 52(6):  1068-1076.  DOI: 10.13209/j.0479-8023.2016.027
    Asbtract ( )   HTML   PDF (1551KB) ( )  
    Related Articles | Metrics

    Based on status assessment of ecological environment and ecological system, this paper mainly analyzed significance and sensibility of ecological functions in Lushan earthquake-hit regions. An optimization program of land spatial pattern for the reconstructions of Lushan earthquake-hit regions was proposed to restore ecosystem function and optimize land spatial pattern. It could be divided into three sub-regions, ecological reserve, eco-agriculture development area, and eco-town development area. Main results are as follows. 1) The ecological protection area is extensive in Lushan earthquake-hit regions, accounting for 80.6% of the total area. In ecological protection area, the protection goal is to maintain ecological security by protect important ecological functions and carry out ecological restoration. 2) The eco-agriculture development area accounts for 13.4% of the total area. As an important agricultural production function zone, the dominant ecological function of this area is to provide safeguard for supply of agricultural products. It also needs providing guarantee of soil conservation function. 3) The eco-town development area only accounts for 6.0% of the total area. This area is the core region of regional urbanization and industrial development. On the premise of protecting ecological, the reconstructions direction is to construct the ecological city through optimization industrial structure and distribution.

    Effects of Silver Nanoparticles on the Accumulation of Cadmium by Lettuce (Lactuca sativa)
    LI Haoyang, WANG Qi, TAN Guangcai, XU Nan
    2016, 52(6):  1077-1084.  DOI: 10.13209/j.0479-8023.2016.114
    Asbtract ( )   HTML   PDF (919KB) ( )  
    Related Articles | Metrics

    The effect of nanoparticle or ionic silver on cadmium accumulation by lettuce (Lactuca sativa) was investigated. The lettuce plants were grown in Hoagland solution amended with 0, 10, 100, 1000 μg/L nanoparticle silver or 0.1, 1, 10 μg/L ionic silver. Half of the lettuce were exposed to 50 μg/L ionic cadmium. After 35 days of exposure, wet weight, dry weight, cadmium, chlorophyll and malondialdehyde of leaves and roots of the lettuces were measured. Results show that except for the 1000 μg/L nanoparticle silver which increased cadmium concentration by about 200% (p<0.001) in lettuce roots, other concentrations of nanoparticle or ionic silver do not significantly change the cadmium concentration in either leaves or roots. Biomass, chlorophyll and malondialdehyde of the lettuces are not significantly changed either. Nanoparticle silver applied as agricultural fungicide in practical amounts will not lead to increased cadmium accumulation or detectable phytotoxicity symptoms in lettuce.

    The Choice of Leading Industry Based on Functional Orientation in the Ecological Conservation Development Area of Beijing
    SUN Chao, LIU Yu, TANG Xiumei, REN Yanmin
    2016, 52(6):  1085-1092.  DOI: 10.13209/j.0479-8023.2016.065
    Asbtract ( )   HTML   PDF (480KB) ( )  
    Related Articles | Metrics

    This study takes the three industries and the internal structure of tertiary industry in ecological conservation development area of Beijing from 2005 to 2012 as the research object, using shift-share analysis method, comprehensively analyses of the development of industry share deviates from the components, structure deviation and competitiveness deviation component, provides some reference for choosing the leading industry in ecological conservation development area and the adjustment of industrial structure. The results shows that the first industry in ecological conservation development area has a certain but small amount competitiveness, cannot effectively promote economic development of the whole area; the second industry growth in ecological conservation development area is slower than the average level in Beijing, and does not have the competitive advantage; the total deviation vector of the third industry presents the obvious rise, and accelerates the development trend, which is the main force of the regional economic development in the future. In potential leading industry selection for districts and counties, Mentougou District takes the culture, sports and entertainment industry, and finance industry as leading industries, Huairou District takes the information transmission, computer services and software industry as the leading industry, Pinggu District takes the culture, sports and entertainment industry as leading industry, in the present stage of the third industry in Miyun County has not meet the requirements of the industry, and the estate industry is the leading industry for Yanqing County. Comprehensive tourism is suitable for the dominant industry of ecological conservation development area, and is also in line with the industry development present situation and future development direction. That can effectively promote regional economic development.

    Partition and Ecological Design Technology of Land Consolidation Project in Tropical Platform Area
    TANG Xiumei, PAN Yuchun, HAO Xingyao, LIU Yu, REN Yanmin
    2016, 52(6):  1093-1101.  DOI: 10.13209/j.0479-8023.2016.103
    Asbtract ( )   HTML   PDF (2031KB) ( )  
    Related Articles | Metrics

    Considering the climate, soil and landform characteristics of tropical area, agricultural development direction and other conditions, the authors explore the land consolidation mode of tropical platform area in Hainan Province based on the analysis of cultivated land consolidation potential. There are four types of land consolidation, the modern agriculture pattern in eastern area, the agricultural tourism integration pattern in southern area, the ecological regulation pattern in western area and the high yield and high efficiency renovation pattern in northern area. Then, the characteristics, potential, the focus of land consolidation direction and key technology of each pattern are analyzed. Combined with the construction of Hainan international tourism island, this paper explores the ecological design modes and scheme of land consolidation project in tropical platform area based on the existing design in land consolidation project, including the design modes of plots, road, irrigation canals and ditches, to meet the climate and landform characteristics of tropical area. The research can provide a scientific basis for the planning and design modes of land consolidation in tropical platform area.

    Influence Major Factors Analysis of Comprehensive Air Quality in the Cities in China
    YANG Yang, SHEN Zehao, ZHENG Tianli, DING Yuchen, LI Bengang
    2016, 52(6):  1102-1108.  DOI: 10.13209/j.0479-8023.2016.115
    Asbtract ( )   HTML   PDF (827KB) ( )  
    Related Articles | Metrics

    Based on the air quality data of five indices in 2010 for 78 main cities of China, the research calculated the comprehensive score of urban air quality, selected ten out of 48 variables describing the climate, topography, urban development and environment management of these cities with multivariate linear regression analysis, and quantified their contribution to the urban air quality. Based on the comprehensive score of urban air quality, the authors used a stratified random sample of 30 from the 78 cities, as a training sample, to construct a radial basis function network (RBFN) model, which was used to simulate air quality of 173 main cities in China based on the natural and social-economic features, and environmental management of the cities. The results indicated that the average saturation vapor pressure, built-up urban area, elevation range, and the percentage of industry in GDP as four major dominants of urban air quality, accounting for the variation by 14.7%, 12.8%, 8.8% and 7.2%, respectively. This study broke the limitation of most previous air quality assessment models, which merely took air pollutants and meteorological factors as input. The result showed a high accuracy (R2=0.658, p<2.2×10-14) of the RBFN model.

    A Study of the Water-Soluble Inorganic Salts and Their Gaseous Precursors at Wangdu Site in the Summer Time
    YE Nini, LU Keding, DONG Huabin, WU Yusheng, ZENG Limin, ZHANG Yuanhang
    2016, 52(6):  1109-1117.  DOI: 10.13209/j.0479-8023.2016.116
    Asbtract ( )   HTML   PDF (2520KB) ( )  
    Related Articles | Metrics

    The authors conducted on-line measurements of water soluble inorganic ions and their gas phase precursors for more than 30 days at Wangdu, Baoding City in summer in 2014 with a Gas and Aerosol Collector (GAC). It was found that, the observation site was always subjected with an ammonia rich conditions; the averaged PM2.5 concentration was 68.2 μg/m3, of which the detected SO42-, NO3-, Cl-, NH4+ and K+ by GAC was 12.6, 8.5, 1.4, 11.7 and 0.7 μg/m3, respectively, consisted 51% of the total mass of PM2.5. All these observed pollutants showed distinct diurnal variations: SO2, SO42-, NO3-, NH4+ and Cl- showed a morning maximum, HCl and HNO3 presented an afternoon peak, and NH3 possessed a day-night variations. As depicted by the analysis of Sulfur and Nitrogen Oxidation Rates (SOR, NOR), fast transformations of trace gases into secondary inorganic aerosols were indicated. The averaged value of SOR and NOR are 0.43 and 0.22, respectively. The variation of SOR and NOR inferred that both gas phase and aqueous oxidations contributed to the fast transformation that formed water soluble inorganic salts.

    Effect of Nitrogenous Heterocyclic Compounds on Anaerobic Filter and Biological Aerated Filter for Treating Coking Wastewater
    HUANG Yi, LIU Sitong
    2016, 52(6):  1118-1124.  DOI: 10.13209/j.0479-8023.2016.118
    Asbtract ( )   HTML   PDF (552KB) ( )  
    Related Articles | Metrics

    Two Anaerobic Filter (AF)-Biological Aerated Filter (BAF) systems, one for bioaugmented system and another for control system, were set-up to treat coking wastewater, and the influence of the introduced nitrogenous heterocyclic compounds on the reactor performance was investigated. The results showed that the COD removal efficiency of AF in both bioaugmented and control system was 35% while the BOD5/COD increased from 0.33 to 0.59 after the treatment of AF in both systems. When 100 mg/L carbazole was introduced to the influent, the COD removal efficiency of the bioaugmented AF remained 35% and BOD5/COD of the bioaugmented AF effluent decreased to 0.53, while the COD removal efficiency of the control AF declined to 23% and BOD5/COD of the control AF effluent dropped to 0.45. When 100 mg/L quinoline and 50 mg/L pyridine were introduced to the influent simultaneously, the COD removal efficiency of the bioaugmented AF decreased to 27% and BOD5/COD of the bioaugmented AF effluent decreased to 0.48, while the COD removal efficiency of the control AF declined to 12% and BOD5/COD of the control AF effluent decreased to 0.38. Moreover, the removal efficiencies of the introduced carbazole, quinolone and pyridine were 83%, 91% and 88% respectively after bioaugmented AF treatment, while the removal efficiencies of the introduced carbazole, quinolone and pyridine were 57%, 66% and 55% respectively after the control AF treatment. This indicated that the bioaugmented system was more effective to resist the impact of high concentration nitrogenous heterocyclic compounds. The GC-MS analysis of the bioangmented AF effluent indicated that the introduction of nitrogenous heterocyclic compounds led to an increment of the alkane and benzoic esters in the AF effluent. This study revealed the impact of the high concentration of organic compounds on A/O system for treating coking wastewater.

    Modelling Relationship between NDVI and Climatic Factors in China Using Geographically Weighted Regression
    HAN Ya, ZHU Wenbo, LI Shuangcheng
    2016, 52(6):  1125-1133.  DOI: 10.13209/j.0479-8023.2015.130
    Asbtract ( )   HTML   PDF (1569KB) ( )  
    Related Articles | Metrics

    Based on the GWR (geographically weighted regression) model supported by ArcGIS, the research explores the multi-scale relationship between vegetation change, climatic factors, and the sensitivity of vegetation to climate factors using AVHRR vegetation cover data combined with temperature and precipitation data in China from 1982–2010. Compared with the general linear regression (Ordinary Least Square, OLS) model, GWR gives a much better fitting result, with the goodness of fit increased from 0.3 to 0.6. The relationship between NDVI, annual rainfall, and average annual temperature has a significant spatial heterogeneity. Regression coefficients of climatic factors decrease from north to south and are higher in the northwest dry region of China. Temperature is more influential than rainfall on NDVI in most areas of China. Each ecological zone has different spatial scales when NDVI and the climatic factors maintain a stable relationship.

    Spatiotemporal Difference of Urban Heat Island in Jing-Jin-Ji Area Based on MODIS Land Surface Temperature
    CHEN Binhui, FENG Yao, YUAN Jianguo, ZHOU Yimin, ZHAO Xinyi
    2016, 52(6):  1134-1140.  DOI: 10.13209/j.0479-8023.2016.104
    Asbtract ( )   HTML   PDF (675KB) ( )  
    Related Articles | Metrics

    Utilizing land cover change (LCC) information together with MODIS land surface temperature in Jing-Jin-Ji area in 2000, 2005 and 2010, spatiotemporal difference of urban heat island (UHI) effects and the factors influenced UHI is explored. Results reveal that the seasonal fluctuations of daytime UHI is bigger than that of nighttime UHI. More than 92.8% of the urban have UHI in the nighttime every season. The strongest daytime UHI happens in summer, but more than 85% of the cities have urban cooling effect in winter. The nighttime UHI in different seasons appear to be similar. The water in urban has different influence to UHI in daytime and nighttime which is to weaken the UHI and to enhance the UHI. The grass in urban enhance the UHI in the daytime of spring and summer and in the nighttime of all seasons but weaken the UHI in the daytime of winter. The forest and the crop land in the urban have the same effect which are weaken the UHI in the daytime of spring, summer and autumn and in the nighttime of all seasons but enhance the UHI in the daytime of winter.

    Characterization of Titanate Products with Different Formation Stages and Adsorption Characteristics of Cd(Ⅱ)
    CAI Bin, WANG Ting
    2016, 52(6):  1141-1147.  DOI: 10.13209/j.0479-8023.2016.108
    Asbtract ( )   HTML   PDF (635KB) ( )  
    Related Articles | Metrics

    Series of products with different formation stages of titanate nanotubes (TNTs) are synthesized, with the hydrothermal reaction time of 1, 2, 3, 4 days. XRD, SAXS and N2 adsorption/desorption have been chosen to detect the morphology and structure of various products. Afterwards, the adsorption behavior of Cd(Ⅱ) onto various products are also compared, and possible mechanism for the different adsorption capacities are detected based on their structures. XRD detection depictes that all products are monoclinic system. Results from SAXS and N2 adsorption/desorption suggeste that the formation processes of TNTs are the disintegration of TiO2→the formation of titanate nanotubes→the destruction of tubular structures. Among all products, TNTs-3d displayes the best defined structure. As for Cd(Ⅱ) adsorption, Langmuir-Freundlich model can better describe the adsorption isotherm, and the adsorption capacities rank as: TNTs-3d ≈ TNTs-1d > TNTs-4d > TNTs-2d. Further detection proves that gyration radius and pore volume play little role, while BET surface area and the average pore diameter possibly affect the adsorption capacity.

    Biosorption of Silver by Magnetically Modified Surface-Engineered Saccharomyces cerevisiae Cells
    TAO Huchun, CUI Xiaobing, LI Jinbo, SHI Gang
    2016, 52(6):  1148-1154.  DOI: 10.13209/j.0479-8023.2016.105
    Asbtract ( )   HTML   PDF (634KB) ( )  
    Related Articles | Metrics

    Surface-engineered yeast (Saccharomyces cerevisiae) cells were magnetically modified using water based magnetic nanoparticles to prepare a new type of magnetically responsive adsorbent. Infrared spectroscopy analysis revealed that magnetically modified cells remained the functional groups of engineered yeast and magnetic materials. The kinetic and adsorption isotherm law and factors influencing adsorption (such as time, temperature and pH) were analyzed. The results showed that adsorption equilibrium was achieved within 18 min. The optimal condition for the Ag+ adsorption was 20~30℃, pH 7.0. The pseudo-first-order kinetic model and Langmuir model fitted the adsorption data well. The results of multi-metal competitive adsorption indicated that magnetically modified cells still showed adsorption selectivity for Ag+ than other heavy metal ions. The adsorption amount of Ag+ was 10.6 times that of Ni2+, 9.0 times that of Zn2+, 7.5 times that of Co2+, 3.0 times that of Cu2+.

    Synthesis of PANI/VGCF Composite and Its Application in Microbial Fuel Cell
    TAO Huchun, SUN Lihong, LI Jinbo, LI Jinlong
    2016, 52(6):  1155-1160.  DOI: 10.13209/j.0479-8023.2016.106
    Asbtract ( )   HTML   PDF (5505KB) ( )  
    Related Articles | Metrics

    The polyaniline/vapor grown carbon fiber (PANI/VGCF) was synthesized by in-situ polymerization, and SEM, FTIR, and TGA were used to investigate the microstructure, polymerization mechanism, and thermal stability. SEM images showed that polyaniline/vapor grown carbon fiber was at nano-scale, and the microstructure was similar with purified vapor grown carbon fiber, which indicated that the polymerization of aniline occurred on the surface of the carbon fibers. FTIR spectra gave further explanation of the composite mechanism and there was no new bond generated. The maximum power density of the microbial fuel cell with polyaniline/vapor grown carbon fiber as modification with a specific loading of 5 mg/cm2 was 299 mW/m2, which was 6.5 times higher than the unmodified microbial fuel cell. The EIS spectra fitted well to the Nyquist model and the equivalent circuit model was given. Polyaniline/vapor grown carbon fiber could be regarded as one economical and potential cathode catalyst for oxygen reduction reaction in microbial fuel cell.

    Soil Seasonal Gleization and Its Ecological Implications in the Alpine Meadow on the Tibetan Plateau
    LIN Li, WANG Qibing, HE Jinsheng
    2016, 52(6):  1161-1166.  DOI: 10.13209/j.0479-8023.2016.107
    Asbtract ( )   HTML   PDF (975KB) ( )  
    Related Articles | Metrics

    In order to investigate soil seasonal gleization process in the alpine meadow on the Tibetan plateau, the soil gleization and its two main controls (high soil organic carbon content (SOC) content and anaerobic environment) were reported in the alpine grassland from Dec. 2013 to March 2014. The results show that the soil seasonal gleization occurres in the humus layer with blue-gray iron and manganese plaques. The soil seasonal gleization occures during the period of soil freezing and thawing, and a positive relationship between the thickness of gleization layer and frozen layer is observed. The process is pseudogley at mild level, with decreasing soil microbial biomass carbon, and increasing cation exchange capacity (CEC), active Fe2+, Mn2+ and availble phosphuros. The reults suggest that soil gleization may subsequently affect microbial community, root mortality, greenhouse gas emmission and nutrient cycling. Although soil gleization appears in the non-growing season, its impacts on the soil ecological processes should not be ignored.