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Table of Content

    20 September 2017, Volume 53 Issue 5
    Orginal Article
    Arc-Length Continuation Algorithm for Nonlinear Finite Element Equations
    Youquan YIN, Yuan DI, Zaixing YAO
    2017, 53(5):  793-800.  DOI: 10.13209/j.0479-8023.2017.072
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    Stability analysis of engineering structures requires tracing equilibrium path of the structure when member’s buckling or material softening occurs. In nonlinear finite element analysis, the traditional Newton method fails at limit point and bifurcation point. The arc-length continuation method can overcome these numerical difficulties. To develop a nonlinear finite element code for stability analysis, the standard iteration formulation of Newton method is presented for the arc-length continuation method. Two practical formulations of the arc-length continuation method and their relationships with the standard form are also discussed. The applicability of the practical formulation is examined by the finite element analysis of stability for a slope.

    Superconducting Quantum Interference Device Detection of Acoustic Nuclear Resonance of Slight Metal Oxidation of the Inner Surface of Enclosed Lead Metal Shield
    Jibo ZHANG, Kehuan LINGHU, Qianhong WU, Ruijuan NIE, Fengmei YU, Furen WANG
    2017, 53(5):  801-809.  DOI: 10.13209/j.0479-8023.2017.047
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    This paper established enclosed cylinder and spherical Pb207 models to give formulas about acoustic nuclear dipole resonance detection of their inner surface oxide-massicot (β-Pb207O). Some calculations on the variations of SQUID-detected magnetic flux dependence of the mass of the metal oxide and the external magnetic field are done to study the feasibility and superiority of SQUID-detected ANR technique under metallic shield with inner surface oxidation. An experiment process was designed which can be used to detect ANR-related parameters using SQUID.

    Extraction of Technetium and Rhenium with Ionic Liquid
    Yue SONG, Taoxiang SUN, Qingde CHEN, Xinghai SHEN
    2017, 53(5):  810-816.  DOI: 10.13209/j.0479-8023.2017.074
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    The extraction of ReO4- and TcO4- by ionic liquids (ILs) were investigated systematically. The results indicated that imidazolium and quaternary ammonium ILs could extract ReO4- and TcO4- efficiently via anion-exchange mechanism. Compared with NTf2-based ILs, PF6-based ILs had a higher extraction efficiency towards ReO4- and TcO4-. With respect to the ILs with an identical anion, the extraction efficiency increased with the increase of the chain length of IL’s cations. The addition of HNO3 and IL’s anion in aqueous phase decreased the extraction efficiency, while the increase of the concentration of IL’s cation led to an opposite effect. At a lower concentration of nitric acid, ReO4- ions were selectively extracted by either [N6,444][NTf2] or [C8mim][PF6] from simulated liquid waste. KPF6 and LiNTf2 aqueous solutions can strip ReO4- effectively from [C8mim][PF6] and [N6,444][NTf2], respectively.

    Simulation of Flow in Continuous-Flow Cloud Condensation Nuclei Counter (DMT-CCNC)
    Renjie YU, Chunsheng ZHAO, Huiwen XUE, Nan MA, Jiangchuan TAO, Shizuo FU, Jianpeng ZHANG, Ye KUANG, Hongjian LIU, Yuxuan BIAN
    2017, 53(5):  817-824.  DOI: 10.13209/j.0479-8023.2017.015
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    The velocity, temperature and humidity in the chamber of the Continuous Flow Streamwise Thermal-Gradient CCN Counter manufactured by DMT were successfully simulated using the computational fluid dynamics software ANSYS FLUENT. With velocity of 0.0164, 0.0185, 0.0205, 0.0226, 0.0246 m/s and temperature settings of ΔT 2, 8 and 17 K, the influence of velocity and temperature on the flow were tested. Results show that, velocity and temperature setting of CCNC influenced both velocity field and temperature field. When ∆T=8 K, v=0.0205 m/s, the supersaturaiton on the centerline was about 0.27%. Supersaturation in the CCNC chamber was simulated successfully.

    Study on the Crustal Structure in Sichuan-Yunnan Region Based on Virtual Deep Seismic Sounding Method
    Dou KANG, Chunquan YU, Jiuhui CHEN, Qiyuan LIU, Jieyuan NING
    2017, 53(5):  825-832.  DOI: 10.13209/j.0479-8023.2017.042
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    By using two seismic profiles along 30°N and 31°N in western Sichuan, China deployed by Institute of Geology, China Earthquake Administration, Virtual Deep Seismic Sounding (VDSS) method was applied to study the crustal structure in Sichuan-Yunnan region. The results show distinct Moho depth from VDSS at Sichuan-yunnan Rhombic Block, Songpan-Garze block and Yangzte block. 1) The Moho depth from VDSS in Sichuan basin is about 40 km, 2) Moho depth from VDSS beneath Sichuan-yunnan Rhombic Block is about 45-50 km, 3) Moho depth from VDSS beneath Songpan-Garze block is about 30-40 km. The Moho depth from VDSS in Sichuan basin is consistent with that predicted from Airy isostasy, while the Moho depth from VDSS at Chuan-Dian Fragment and Songpan-Garze block is clearly shallower than the Moho depth from previous receiver function studies, and those predicted from the Airy isostasy as well. These results may suggest that the crustal structure beneath Sichuan basin is relatively simple while there are complex crustal structure beneath Sichuan-yunnan Rhombic Block and Songpan-Garze block. In addition, the Moho depth from VDSS are clearly reduced at Xianshuihe fault and Anninghe fault, which might reflect mantle upwelling along the fault zones. The results provide new constrains to understand the deformation mechanism at southeastern margin of Tibetan Plateau.

    Research on Geomorphological Morphology and Regionalization of Hoh Xil Based on Digital Elevation Model (DEM)
    Li XU, Jianghai LI, Chiheng LIU, Xin CUI
    2017, 53(5):  833-842.  DOI: 10.13209/j.0479-8023.2017.041
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    The geomorphological morphology was analyzed quantificationally and the geomorphological regionalization was studied detailedly based on Digital Elevation Model (DEM) of Hoh Xil area combinated with platform of Geographic Information System (GIS). Research suggests that the Hoh Xil area composes of three types in terms of absolute altitude: the middle, the high and the highest, and the high altitude type makes up about 69.38%. Due to the formation of planation surface, the relief amplitude in this area is less than 200 m mainly included plain, tableland and hill. Rivers headward erosion caused by strong uplift of Qinghai-Tibet plateau was not exert an influence on the Hoh Xil except Sanjiangyuan region. So the primary compose of slope type are micro slope, slow slope and slope which all less than 15°. According to regional differentiation of the essential geomorphological types and their genesis, the Hoh Xil is divided into four major geomorphological regions: the Qiangtang plateau (Region Ⅰ), the east Kunlun mountains (Region Ⅱ), Sanjiangyuan hill mountains (Region Ⅲ) and Qaidam plateau and basins (Region Ⅳ). Moreover, the Region Ⅰ is divided into Hoh Xil plateau lake basin (SubregionⅠ1) and Dangla high mountains (SubregionⅠ2). The Region Ⅱ is divided into southern highest mountain (Subregion Ⅱ1) and northern high mountains (Subregion Ⅱ2). The morphology research which reflect altitude, relief and slope and regionalization research which show geomorphological pattern and horizontal differentiation of plateau, mountain land, mountain plateau and basin will be of great significance in geomorphic, landform type and exploitation, protection in Hoh Xil.

    Comparative Study of Famennian Carbon Isotope Characteristics of Junggar, Xinjiang and Central Hunan, South China
    Pu ZONG, Xueping MA, Meiqiong ZHANG, Yubo ZHANG, Dan LÜ
    2017, 53(5):  843-861.  DOI: 10.13209/j.0479-8023.2017.055
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    In order to clarify the position of the Frasnian/Famennian (F/F) boundary in the Lower Member of the Hongguleleng Formation of northwestern Junggar Basin, Xinjiang, carbon isotope characters were comparatively studied for the carbonates from the Lower Member of this formation in the Bulongguoer section of Junggar and the interval (lower-middle Famennian of the Upper Devonian) at the Xikuangshan section of central Hunan. The age of the Lower Member of the Hongguleleng Formation is re-investigated, on the basis of its integrative biostrati-graphical evidence, carbon isotope features, and a comparison with carbon isotope data from the Xikuangshan section. The carbon isotopic trend from the Lower Member of the Hongguleleng Formation does not show any prominent positive excursion and is distinctly different from the δ13C oscillation pattern across the F/F boundary recorded in several typical sections around the world; the δ13C values at Bulongguoer vary from 0 to 1‰, which is lower in amplitude than the currently known positive shift (2‰-3‰) across the F/F boundary in the world. The Lower Member of the Hongguleleng Formation probably may not contain Frasnian deposits, or even lacks the basal part of the Famennian (Pa. triangularis conodont Zone). For the early-middle Famennian interval of the studied sections, the carbon isotope trend seems to be well comparable; and this trend can be divided into three phases: two positive-negative oscillation cycles, followed by a weak positive excursion. The characteristics of major elements indicate that the lower part of Unit 3-1 in the Bulongguoer section was affected by terrigenous supply, which is inferred to probably be related to strong regional tectonic activities.

    Study of Spatial Interaction and Nodal Attractions of Municipal Cities in China from Social Media Check-in Data
    Zeya HE, Bihu WU, Yu LIU
    2017, 53(5):  862-872.  DOI: 10.13209/j.0479-8023.2017.084
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    To investigate the spatial interaction effect and nodal attractions of cities, a set of inter-city social network location-based check-in data with a time span of one year among 348 municipal cities in China is examined with a PSO (Particle Swarm Optimization) method and the gravity model. Twelve variables related with economic development, industrial structure, population scale and structure, tourism competitiveness and educational level are introduced to further investigate their influences on nodal attractions of cities. The results indicate a distance decay effect which is relatively weaker than in other systems, suggesting that human mobility at the regional level is less sensitive to the change in geographic distance. A close examination of the nodal attractions suggests variables related to the cities’ tourism competitiveness, maturity of development and population scale significantly influence the value of nodal attractions. This article will serve as a stepping-stone for a better future understanding of human travel pattern, check-in behaviors and the real meaning of nodal attractions in some complicated networks.

    A Bayesian Estimation-Based Algorithm for Geomagnetic Aided Inertial Navigation
    Yuefeng LIU, Peichen ZHENG
    2017, 53(5):  873-880.  DOI: 10.13209/j.0479-8023.2017.016
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    For existing algorithms are difficult to satisfy the applied requirements, a Bayesian estimation-based algorithm for geomagnetic aided inertial navigation is proposed for aerocraft navigation. The core idea is to convert position estimation to probability estimation. A position correction strategy is also provided in this algorithm. Simulation experiments were performed in which measured data were used. Results show that the algorithm has an average navigation accuracy of 89 meters and spend average 156 seconds for first correction the INS (inertial navigation system). In addition, the performance of the algorithm is not sensitivity to initial estimation errors.

    Comparative Study on the Thermal Environment Effect of Six Urban Underlying Surfaces
    Yajun YANG, Zhendong ZOU, Wenli ZHAO, Guoyu QIU
    2017, 53(5):  881-889.  DOI: 10.13209/j.0479-8023.2017.014
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    Surface temperature characteristics of six typical underlying surfaces, namely, asphalt pavement, cement pavement, grass, marble pavement, pavement bricks and grass-planting bricks, were observed with thermal infrared imaging technology. The diurnal and seasonal variations of surface temperature of different underlying surfaces were systematically analyzed. By means of the standard deviation (SD), the temporal and spatial microclimatic dynamic characteristics of different underlying surface temperature were revealed. The results are as following. 1) Diurnal variation of surface temperature of different underlying surfaces present unimodal pattern, diurnal variation of grass surface temperature changes greatly from season to season. Asphalt surface temperature is highest among the whole year, having a great effect on thermal environment while temperatures of grass-planting bricks and marble pavement are the lowest, having a relief effect on thermal environment, especially in summer. 2) The daily average temperature of different underlying surfaces are higher than air temperature, showing that underlying surface keeps heating the air throughout the year. 3) The underlying surface temperature is strongly affected by air temperature, relative humidity and solar radiation. Air temperature and solar radiation are positively related with surface temperature, showing that air temperature and solar radiation play a role in warming the land surface. On the contrary, relative humidity is negatively correlated with surface temperature, turning out that relative humidity plays a role in cooling the land surface. 4) Grass-planting bricks have a more stable thermal environment than grass and marble bricks. Temperature changing characteristic of asphalt pavement best represents the spatial and temporal variation characteristics regarding the temperature of underlying surface. The results have certain reference significance for knowing thermal environment of different urban underlying surfaces, while providing scientific evidence for alleviating urban thermal environment.

    Pore Structure Characteristics of Sludge Biochars during Pyrolysis with Various Pyrolysis Temperatures and Holding Times
    Siqi TANG, Jingchen WANG, Ko Jaehac
    2017, 53(5):  890-898.  DOI: 10.13209/j.0479-8023.2017.085
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    Municipal sewage sludge was pyrolyzed, under various pyrolysis temperatures and holding times, to investigate the pore structure characteristics of the sludge-based biochars obtained. The pore structure of the obtained sludge biochars was measured by the N2 adsorption/desorption at 77 K. The concept of fractal dimension was introduced to determine the pore surface roughness. Experimental results showed that the BET surface area of the sludge biochars increased with pyrolysis temperature increasing, achieving the maximum (i.e. 92.3 m2/g) at 600ºC; the further increase of pyrolysis temperature decreased it. When pyrolysis temperature was less than 500ºC, mesopores were dominant on the obtained biochars and micropores were not observed; over 500ºC, the main pore species were micropores and mesopores. The shape of pores on the sludge biochars differed as pyrolysis temperature increased, varying from silt-shaped pattern to thorough and plate-like patterns. The increase of holding time little altered the pores’ shape but did the pore volume. The pore surface fractal dimensions of the obtained biochars intended to increase with pyrolysis temperature, whereas the prolonging of holding time decreased it at 600-700ºC and augmented it over 700ºC.

    Treatment of 2,4-DNT-3-SA Contaminated Soil by a Biological Leaching Method
    Tianyu ZHANG, Quanlin ZHAO, Zhenzhong ZHANG, Zhenming JIANG, Hongping SU, Xuewen GAO, Zhengfang YE
    2017, 53(5):  899-904.  DOI: 10.13209/j.0479-8023.2017.094
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    A static biological leaching method was used to treat the 2,4-DNT-3-SA contaminated soil. The effects of oxygen conditions, soil to water ratio and temperature on the removal efficiency of 2,4-DNT-3-SA were evaluated. The result suggested that under the aerobic and 37ºC conditions, the removal efficiency of 2,4-DNT-3-SA reached more than 98% when the ratio of soil to water was 10:5. High-throughput sequencing results indicated that the dominant bacteria in the soil were Genus Pseudomonas, Sphingobium and Sporolactobacillus.

    Impact of Railway High-Speed on the Urban Spatial Interaction: A Case Study of Beijing-Shanghai Line
    Huaxiong JIANG, Xiaochen MENG
    2017, 53(5):  905-912.  DOI: 10.13209/j.0479-8023.2017.097
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    Taking Beijing-Shanghai High-speed Rail as an example, this paper makes an analysis about the impact of city scale, distance, departure frequency upon the intensity of passager flow between cities, and decomposes the Time Saving effect of high-speed rail and departure frequency effect. A multiple liner regression model is constructed to analyze whether both effects are significant, under the control of the scale variable. The results show that Beijing-Shanghai High-speed Rail makes a readjustment of the passager flow between cities, leading to an decreasing impact of the scale variable upon the urban spatial interaction; the influence of the distance variable is significant in 2014, of which the absolute coefficient decrease, and which means passager flow is less sensitive to the spatial distance, leading to the increase of passager flow of the long-distance city-pairs. Therefore, the time saving effect of high-speed rail makes the distance less important for urban spatial interaction. The coefficient of the departure frequency variable is also significant in 2014, resulting from high-speed rail increasing the total departure frequency, and exalting the intensity of medium, medium-high departure frequency city-pairs, which means that the effect of departure frequency makes the departure frequency more important for urban spatial interaction.

    Risk Assessment of Perfluoroalkyl Compounds (PFCs) in Water and Sediment Samples of Hanjiang River
    Jie LI, Yue GAO, Zhifen WANG, Binwei WANG, Hongshan HAO, Yaru XU, Tingting ZHU, Nan XU, Jinren NI
    2017, 53(5):  913-920.  DOI: 10.13209/j.0479-8023.2017.096
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    Contamination profiles of 11 kinds of perfluorinated compounds (PFCs) were analyzed by using ultra high performance liquid chromatography-triple quadrupole mass spectrometry in water and sediment samples of Hanjiang River in dry and wet seasons. The results showed that 11 kinds of PFCs were all detected. The total concentrations of PFCs in water and sediment were 0.3-23.04 ng/L, 0-55.1 ng/g in dry season and 0.16-19.68 ng/L, 0.99-85.07 ng/g in wet season. The maximum concentration of PFCs was detected in Wuhan where Hanjiang River feeds into Yangtze River. Meanwhile,Wuhan had the highest concentration of perfluorooctanoic acid (PFOA) with 22.52 ng/L in dry season and 12.52 ng/L in wet season. Perfluoroheptanoic acid (PFHpA) and perfluorohexanoic acid (PFHxA) were the dominant PFCs in sediment and the highest total concentration of PFCs was detected in Taocha. There was little difference in the concentration composition of ∑PFCs in sediment in both seasons. The risk quotient method was used for the ecological risk assessment of PFOA, perfluorooctane sulfonic acid (PFOS), perfluorononanoic acid (PFNA), PFHxA and perfluorodecanoic acid (PFDA) in water, and PFOA and PFOS in sediment based on the measured environmental concentration (MEC) and the predicted non-effect concentration (PNEC) of target pollutants.The assessment results suggest that the above PFCs in water and sediment of Hanjiang River posed no ecological risk to environment.

    Distribution of Rare Earth Elementsin the Soft Tissue of Hyriopsis cumingii and the Correlation with Metal Speciation of Sediments in Poyang Lake
    Xuming XU, Baozhu PAN, Fengyue SHU, Xiufen CHEN, Jinren NI
    2017, 53(5):  921-928.  DOI: 10.13209/j.0479-8023.2017.095
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    Hyriopsis cumingii and corresponding sediment in five respective monitoring sections of Poyang Lake were sampled in autumn 2014, followed by the detection of rare earth elements (REEs) in the soft tissue of Hyriopsis cumingii and sediments treated by BCR sequential exaction. As results, the mean value of total REEs in the soft tissue of Hyriopsis cumingii was 15.52 mg/kg, and light REEs were more easily accumulated, indicating that the biological effect of light REEs on Hyriopsis cumingii was stronger than heavy REEs. Correspondingly, the mean value of total REEs in sediments was 285.22 mg/kg with higher light REEs, suggesting the strong terrigenous properties. The REEs concentration in the sediment treated by BCR sequential extraction ranked as: residual fraction>reducible fraction>oxidizable fraction>exchangeable fraction. The exchangeable fraction displayed the lowest REEs concentration but the largest difference in spatial distribution; however, they were all under low risk level analyzed by Risk Assessment Code. Significant and positive correlations can be observed between REEs in Hyriopsis cumingii and that in the oxidizable fraction of sediments, suggesting that the bioavailability of REEs would mainly depend on REEs bound to organic matter.

    Simulation of Pollution Characteristics and Source Apportionment of Ozone in Tianjin during Summer Time
    Linan HONG, Zhengchao HUANG, Momei QIN, Xuesong WANG
    2017, 53(5):  929-938.  DOI: 10.13209/j.0479-8023.2017.109
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    Models-3/CMAQ and High-order Decoupled Direct Method (HDDM) was applied to simulate the ozone pollution during July 2014 in Tianjin, and then to analyze the distribution of ozone-precursor sensitivity regimes and to quantify the impact of source emissions from Tianjin and surrounding areas. The distribution of ozone concentration in Tianjin was gradually increased from the center urban areas to the suburbans areas. The concentrations in Binhai new district (in the southeast of Tianjin), was the highest. Ozone formation was mainly VOCs-sensitive in Tianjin in July, the central area (Central city, Beichen, Dongli and Binhai new district) was VOCs-sensitive over 95% days, near 2/3 of simulation days in northern suburbs (Jixian, Baodi, Ninghe and Wuqing) and Jinnan in central area was VOCs controlled, VOC-sensitive regime had similar probability of occurrence to mixed sensitive regime in southern suburbs (Xiqing, Jinghai and Dagang). Shandong Province contributed 1/4 to ozone in Tianjin, was the main source of Tianjin summer ozone, significantly influencing the level of ozone in the southeast coastal of Tianjin. The average contribute of Hebei Province was 1/6. It main effected of western area of Tianjin. Tianjin local emissions contributed in Baodi and Jixian in the north of Tianjin.

    Impacts of Land Use Changes on Ecosystem Service Value in Hongsipu Irrigated Area
    Xinyue HU, Yuqin SONG, Lei LU
    2017, 53(5):  939-947.  DOI: 10.13209/j.0479-8023.2017.108
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    Based on related study on land use and methods of ecosystem service value assessment, using GIS technology, this paper analyzed the land use changes of Hongsipu irrigated area 1996, 2000, 2006 and 2010 and calculated ecosystem service value, in order to study how the ecosystem service value changes with the land use. Results showed that the changes of land use in Hongsipu irrigated area were significant from 1996 to 2010. The main land use types are grassland, cropland and sandy wasteland. In 1996 the main type was grassland while in 2010 it’s changed to cropland. During 1996 to 2010, grassland area decreased and cropland area increased most significantly, followed by the increase of construction land and woodland area, while water area changed slightly. Total ecosystem service value of the study area increased from about 249.56 million yuan in 1996 to about 266.64 million yuan in 2010, which showed an increasing tendency. It’s the increase of cropland and woodland area that caused the increase of total ecosystem service value. And also the ecosystem service value of cropland, woodland and water accounts for 84.59% of the total ecosystem service value. The distribution of unit area ecosystem service value is also closely related to land use changes and directly reflects the process of land use change during the irrigated area construction and development, indicating that the land use changes of Hongsipu irrigated area had a positive effect on total ecosystem service value increase.

    Integrated PCA-BN Approach for Identifying the Water Quality Response Patterns for Lakes in Yunnan Plateau
    Qingsong JIANG, Zhongyao LIANG, Lei ZHAO, Yuzhao LI, Sifeng WU, Yong LIU
    2017, 53(5):  948-956.  DOI: 10.13209/j.0479-8023.2017.113
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    An integrated approach of principle components analysis (PCA) and Bayesian network (BN) for identify- ing the response pattern of different clusters were developed to understand sensitive relationships of water quality in lakes of Yunnan Plateau. The model includes four steps: data preconditioning, lakes clustering with PCA, Bayesian network learning and lake water quality response modeling. The results demonstrate that the 26 lakes can be clustered into two groups; the Chl a concentration responds more significantly to Total Nitrogen (TN) and Total Phosphorus (TP) in the first group, mainly resulting from much higher watershed disturbances; the Dissolved Oxygen (DO) in the first group with higher water temperature is close to saturation and have little change with Chl a increasing, while the second group is not; and there is good consistency on the relationship between Transpa-rency (SD)and Chl a in both groups.

    Denitrification Performance of a Denitrifier-Augmented Packed-Bed Bioreactor with Solid Carbon Source
    LU Ting, YANG Luhua, YANG Feifei, WU Weizhong
    2017, 53(5):  957-963.  DOI: 10.13209/j.0479-8023.2017.114
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    The authors investigated the bioaugmentation performances of a selected bacterial strain for denitrification in a packed bed bioreactor using PBS as solid carbon source. Fluorescence quantitative PCR was employed to analyze the microbial community composition in the bioreactor. Results indicated that the denitrifier named W14 could remarkably improve denitrification efficiency. At HRT of 0.5 h, nitrogen removal was found to be higher than 90% and the residual DOC of effluent was greatly reduced. Addition of selected denitrifiers led to an increase of nirS gene abundance and proportion, indicating that inoculation of selected bacterial strain could boost denitrifiers’ proliferation and enhance nitrogen removal eventually.

    Orginal Article
    A Study of Meto-Drought in Nujiang and Lancang River Basins in Yunnan Province during Recent 50 Years
    Juan XU
    2017, 53(5):  964-972.  DOI: 10.13209/j.0479-8023.2017.106
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    The observed precipitation and temperature data of 31 meteorological stations from 1965 to 2013 in Nujiang and Lancang river basins in Yunnan Province were collected and the standardized precipitation evapo-transpiration index (SPEI) was employed to analyse the drought processes of each bio-climate zone in the two basins. The occurrence frequencies and severities of the meteorological droughts were computed in annual, seaso- nal and monthly scale. The spatial and temporal change and the intensity of drought occurrence in the study area were revealed. The results show that there was a significant increasing trend in seasonal and monthly drought since the late 1970s; the drought occurred without obvious spatial distinction among the bio-climate zones. In the recent 50 years, the significant increase of drought in the study area may be attributed to the significantly raising in temperature, rather than the lightly decline of the precipitation.

    Community Structure Characteristics of Macroinvertebrate from Yichang to Wuhan in the Middle Reaches of the Yangtze River
    Xiufen CHEN, Wei XIA, Baozhu PAN, Xuming XU, Jinren NI
    2017, 53(5):  973-981.  DOI: 10.13209/j.0479-8023.2017.112
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    To explore the status of macroinvertebrate communities and the main influencing factors, an investigation was carried out at 29 sampling points (4 sections) and 40 sampling points (5 sections) in the middle reach of the Yangtze River, respectively in April and October in 2014. 34 species were identified in April (spring) and 32 species in October (autumn). Arthropods is the dominant class of macroinvertebrate in both seasons, up to 56% and 35% respectively. Spring’s species abundance, the average density as well as the biomass are the highest in two quarters, and from top to bottom in the middle reach of Yangtze River biomass reduced gradually. The results of functional feeding groups show that collector-gatherers are the main components in the middle reach of Yangtze River in spring (40.25%) and autumn (59.3%). The results of tolerance value show that semi-tolerant to pollution and pollution tolerant organisms are the main components in the middle reach of Yangtze River and Wuhan section has more pollution tolerant organism in the two quarters. The correlation analysis on 5 kinds of functional feeding groups and three kinds of biological standing crop with the 7 environmental factors show that the influence of environmental factors on macroinvertebrate is different in the spring and autumn, TP and TN as well as particle size are the main environmental factors in spring, while in autumn, the benthic animals are mainly affected by pH, dissolved oxygen and transparency. This study has a comprehensive understanding of the benthic fauna from several aspects and can provide basic information for intensive research of the Yangtze River.

    An Iron-doped Cathode with PEI/MWCNT Modified Carbon Felt Outer Layers for Dyeing Wastewater Treatment by Electro-Fenton System
    Huchun TAO, Gang SHI, Taian YU, Jinlong Li, Jinbo LI, Nan XU
    2017, 53(5):  982-988.  DOI: 10.13209/j.0479-8023.2017.111
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    An iron-doped (using limonite as the source of iron) cathode with PEI/MWCNT (polyethylenimine/ Multi- walled carbon nanotube) modified carbon felt outer layers was prepared for Electro-Fenton systems. PEI/MWCNT multi-layers could significantly increase the production of H2O2. The highest H2O2 accumulation was achieved up to 66.5 ± 2.4 mg/L at -0.95 V, neutral pH and 200 mL/min of aeration rate, which increased about 56.8% than the carbon felt at the same condition. The PEI/MWCNT multi-layers were stable enough that there was no obvious decrease in H2O2 accumulation after 20 recycles. This study tested the performance of the prepared cathode in treating the simulated dyeing wastewater. The results were as follows: Orange II with initial concentration of 20 mg/L at neutral pH (pH0=6-7) was discolored completely after 60 min electrolysis process, and the decolorizing efficiency was up to 96.8%. In addition, the prepared cathode was stable enough and could be reused without catalytic activity decrease. This study also tested the performance of the prepared cathode in treating the actual dyeing wastewater. The chroma, COD and ammonia-nitrogen removal efficiency after 120 min electrolysis process were 91.7%, 69.4%, and 56.2% respectively.