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25 July 2012, Volume 2012 Issue 4 Previous Issue    Next Issue

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Finite element computation and analysis on complex contact boundary HOU Lei, LI Han-ling, LIN De-zhi, ZHANG Min, Daglish GEORGE 2012, 2012 (4):  1-11,26.  Abstract ( 2253 )   PDF (4332KB) ( 2594 )   Save The safety test of transportation devices, including impact test and plastoelastic deformation, is simulated both in laboratory and by computer. Contact deformation algorithm is an international standard method to simulate the skid control on complex 3-D areas. In this paper, coupled non-Newtonian fluid equations with initial boundary value are used to solve the 3-D layer structure. A finite element method (FEM) based on the variation principle is used to solve the perturbation problem, and data mining is processed by high performance software. According to the embedding principle, a stratified element division is processed, and the complex boundary is divided into several mutual connected yet not overlapped hexahedral and square elements. After building a FEM model of both macro scale and micro scale, varying curves of parameters including energy and velocity can be obtained. On the other hand, the boundary layer theory of asymptotic perturbation method is also a way to study the complex boundary problem. The characteristic function space gained can be used both to optimize the primary function of FEM, and to establish a new asymptotic method to solve the nonlinear eigen problem. It can be used to estimate the specific parameters of materials as well. The stochastic analysis of artificial boundary conditions is then used to study the resulting data. References | Related Articles | Metrics

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Young type inequalities for matrices HU Xing-kai 2012, 2012 (4):  12-17.  Abstract ( 3365 )   PDF (144KB) ( 5043 )   Save First, some Young type inequalities for scalars were given. Then on the base of them, corresponding Young type inequalities for matrices were established. References | Related Articles | Metrics

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Some sharp lower bounds for spectral radius of connected graphs GONG He-lin 2012, 2012 (4):  18-26.  Abstract ( 2214 )   PDF (201KB) ( 2460 )   Save This paper studied lower bounds on the spectral radius of connected simple graphs and proved an useful inequality for the number of walks. Furthermore, some new lower bounds on the spectral radius of graphs were provided in terms of the maximum and minimum degree, the average degree, the 2-degree and the number of $k$-walks(with $k$ vertexes). By applying the properties of similar matrices and the Weyl inequalities,  another lower bound was obtained by means of the number of $k$-walks.  Simultaneously, all extremal graphs which achieve above bounds were also characterized. References | Related Articles | Metrics

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Numerical method for option pricing under jump-diffusion process LI Wei, ZHOU Sheng-wu 2012, 2012 (4):  27-35.  Abstract ( 3059 )   PDF (471KB) ( 2579 )   Save Numerical method for partial integro-differential equation (PIDE) resulting from option value under jump-diffusion process was studied. A non-homogeneous linear system was obtained by discretizing the spatial derivatives utilizing the fourth-order difference and extending boundary using fourth-order Lagrange interpolating polynomial. Based on $\mathrm{Pad\acute{e}}$\ approximations and partial fraction version of the matrix exponential, a high-order smoothing Crank-Nicolson scheme was constructed. Numerical calculation discussed the influence of jump intensity on vanilla option value and barrier option value, showed that the algorithm was efficient. Compared with classic Crank-Nicolson scheme, the numerical scheme avoided the spurious oscillation near the strike price and barrier value. The algorithm also can be used in the general linear boundary value problem which has non-smooth boundary. References | Related Articles | Metrics

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Harnack estimate for the Schrodinger equation under Ricci flow WANG Jian-Hong 2012, 2012 (4):  36-42.  Abstract ( 2353 )   PDF (241KB) ( 2279 )   Save This paper established the gradient estimate and Harnack inequalities of the Schrodinger equation when the metric is evolved by Ricci flow, and extended the results ofthe heat equation by C.M.Guenther References | Related Articles | Metrics

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Electrical conductivity properties of P(MMA-St)/MWNTs composites ZHI Hui, XU Xue-cheng 2012, 2012 (4):  43-49, 60.  Abstract ( 2358 )   PDF (2515KB) ( 2151 )   Save Methyl methacrylate-styrene copolymer-encapsulated multiwalled carbon nanotubes(MWNTs) composites were prepared via situ emulsion polymerization. The influence of the MWNTs content and the monomer ratio of the copolymer on the properties of composites were studied. The relationship between the structure, interaction and properties of the composites were initiated by SEM, FTIR, Raman and XPS. The results indicated that the thermal stability and electrical conductivity of the composites are enhanced with addition of MWNTs. When the content of MWNTs unchanged, the interaction between copolymers and MWNTs enhanced with increasing the content of PMMA chains segment. Copolymers are encapsulated on the surface of MWNTs evenly and the thermal stability and electrical conductivity of composites became higher. References | Related Articles | Metrics

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A general decellularization method for preparing vascular scaffolds from blood vessels of different types, diameters and wall-thicknesses ZHANG Hong-xia, ZHAI Wan-yin, ZHANG Hong-feng 2012, 2012 (4):  50-60.  Abstract ( 2803 )   PDF (5808KB) ( 3932 )   Save This study was to build a general decellularization method by combining trypsinization with repeated frozen/thawing treatment for different types of vessels including saphenous vein, carotid artery and aorta. Saphenous vein, carotid artery and aorta were decellularized by trypsinization and repeated frozen/thawing treatment. The efficiencies of cell removal and extracellular matrix (ECM) integrity were examined by Hematoxylin and eosin staining, Masson Trichrome staining and Weigert’s staining. A quantitative means based on image analysis software was used to quantify the ECM preservation. Scanning electron microscopy was used to show the extracellular matrix integrity. Histology staining and quantitative analysis demonstrated trypsinization with repeated frozen/thawing treatment decellularized the saphenous vein, carotid artery and aorta completely. The ECM structure was optimally preserved and integrity. Scanning electron microscopy examination also showed the ECM was well-preserved and the fibers were dense and orderly. The present results revealed that the trypsinization with repeated frozen/thawing method is a promising one for preparing decellularized vascular scaffolds of different types, sizes and wall-thicknesses of blood vessels. References | Related Articles | Metrics

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Quantitation and localization of allanoicase during the development of Dictysotelium discoideum DAI Hui, HOU Lian-sheng 2012, 2012 (4):  61-66.  Abstract ( 1875 )   PDF (1709KB) ( 2172 )   Save Location and expression of allanoicase were observed in the wild type KAx-3 and mutant type AK127 cells during development by immunofluorescent technique and Western blot, respectively. The results showed that abundant of allanoicase existed near the cytomembrane at the aggregation stage. At the mound stage, the fluorescence of allanoicase in the peripheral cells of mound was stronger than other place cells. When they developed into slug stage, more allanoicase existed in prestalk cells than that in prespore cells. The fluorescence of allanoicase expressed strongly at the junction of prespore area and prestalk area at the fruiting body stage,these cells would differentiate into prestalk B cells. These data indicated that there may be some relationships between the expression of allanoicase and cell-type differentiation during Dictysotelium discoideum development. The results of western blot showed that the expression of allanoicase increased gradually in the development of KAx-3 cells. The expression amount of allanoicase was maximum when the cells developed nearly 18 h. But the expression of allanoicase in AK127 cells which gene of gp150 protein was knocked out was always at a low level. It shows that the expression of allanoicase would be affected in the absence of gp150. The results indicate that the expression of allanoicase has some relationships with the developmental time of the cells, and is also associated with the expression of gp150 gene. References | Related Articles | Metrics

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Overexpression and characterization of a bacterial α-N-acetylgalactosaminidase LIN Yi-gang, XIA Gang 2012, 2012 (4):  67-74.  Abstract ( 2426 )   PDF (1764KB) ( 2636 )   Save The coding sequence of alpha-N-acetylgalactosaminidase (A4) was amplified from genomic DNA of Chryseobacterium meningosepticum and subcloned into pET24a, which was then transformed into BL21(DE3) for overexpression of His-A4. The overexpressed His-A4 enzyme was purified by using affinity chromatography and its activity was comparable to that previously reported by using a conventional method with an artificial substrate. To better measure the activity of α-N-acetylgalactosaminidase in real application, we established a novel method in which we directly used the surface antigen of red blood cell as substrate and applied ELISA to the detection of un-cleaved antigen. The activity of His-A4 was evaluated in the new ELISA method and was demonstrated to be able to decrease the blood cell surface antigen-antibody reaction in concentration- and time-dependent manner. References | Related Articles | Metrics

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Effect of forebrain NR2B overexpression on social interactions in transgenic mice ZHANG Ning, LI Chun-xia 2012, 2012 (4):  75-82.  Abstract ( 2105 )   PDF (1797KB) ( 2427 )   Save Male and female NR2B transgenic mice and their littermate controls were subjected to the social interaction test in a novel environment, sociability test and social novelty test. There was no significant difference in social interaction test in a novel environment and social novelty test among these four groups. However, compared with wild type mice, female but not male NR2B transgenic mice exhibited improvement in sociability. These results suggest that NR2B overexpression in the forebrain can improve sociability of female mice, while having no significant effect on social behaviors in male mice. References | Related Articles | Metrics

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Combined morphological and molecular analyses of higher taxa in Ostracoda YU Na, LI Er-chao, CHEN Li-qiao 2012, 2012 (4):  83-94.  Abstract ( 1989 )   PDF (1288KB) ( 2153 )   Save 27 morphological characters and 18S rDNA sequences of the 9 main ostracod groups were analyzed by the maximum parsimony method to construct a consensus phylogenetic tree. The results indicate that punciidaen ostracods form a separate clade which may be placed under the subclass ‘Punciocopa’, with the same status as Podocopa and Myodocopa, but more evidence is still needed to confirm it. The classification status of halocypridian ostracods was undetermined because the topology was different on two phylogenetic trees. Among the three subclasses suggested in the study, Podocopa includes the suborders Cypridocopina, Cytherocopina, Bairdiocopina, Darwinulocopina and the family Cytherellidae; Myodocopa consists of at least two orders, Cladocopida and Myodocopida; and Punciocopa has only one family, Punciidae. This provides new evidence for solving the unstable higher classification of living ostracods. References | Related Articles | Metrics

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Contribution to the knowledge of Carabidae (Coleoptera) from Isfahan Province, Iran Hassan GHAHARI， Memis KESDEK 2012, 2012 (4):  95-101, 141.  Abstract ( 2169 )   PDF (492KB) ( 2204 )   Save Ground beetles (Coleoptera: Carabidae) are powerful predators which have efficient role in biological control of agricultural and forest pests. The fauna of these beneficial insects from Isfahan province in central Iran is studied in this paper. Totally 42 species and subspecies from seven subfamilies (Broscinae, Carabinae, Cicindelinae, Harpalinae, Lebiinae, Nebriinae, Pterostichinae) were collected and identified. Of these six species including, 〖WTBX〗Cephalota 〖WTBZ〗(〖WTBX〗Taenidia〖WTBZ〗) 〖WTBX〗circumdata cappadocica 〖WTBZ〗Franzen, 〖WTBX〗Lophyridia concolor concolor 〖WTBZ〗Dejean,〖WTBX〗 Lophyridia littoralis mandli 〖WTBZ〗Mandl, 〖WTBX〗Ophonus 〖WTBZ〗(s.str.) 〖WTBX〗cribricollis 〖WTBZ〗(Dejean),〖WTBX〗 Pachycarus 〖WTBZ〗(〖WTBX〗Paramystropterus〖WTBZ〗)〖WTBX〗 bravipennis 〖WTBZ〗Chaudoir and 〖WTBX〗Cymindis 〖WTBZ〗(s.str.) 〖WTBX〗scapularis 〖WTBZ〗Schaum are new records for Iranian fauna. References | Related Articles | Metrics

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Characteristics of the avian community in winter in Caohai of Guizhou Province, China LUO Zu-kui, LIU Wen, LI Zhen-ji, MA Guan-wei, PAN Juan 2012, 2012 (4):  102-111.  Abstract ( 3180 )   PDF (525KB) ( 2474 )   Save By the method of line transect, a bird survey was conducted in the Caohai Nature Reserve of Guizhou Province from December 2010 to January 2011. Habitats were classified into six catalogues, i.e. farmland, vegetable land, grassland, low water area, deep water area and woods. A total of 88 bird species was recorded, which belonged to 33 families and 13 orders. Among the bird species recorded, 1 species was in the GradeⅠnational key protected birds and 6 species was in the Grade Ⅱ, respectively. The overall density (D), 〖WTBX〗α 〖WTBZ〗diversity index (H′), predominant index (〖WTBX〗C〖WTBZ〗) and evenness (〖WTBX〗J〖WTBZ〗) of the avian communities were 12.14 ind·hm-2, 2.98, 0.91 and 0.67, and the species, 〖WTBX〗D〖WTBZ〗, 〖WTBX〗H′〖WTBZ〗, 〖WTBX〗C 〖WTBZ〗and 〖WTBX〗J〖WTBZ〗 were 27～35 species, 3.93～33.76 ind·hm-2, 1.61～2.78, 0.41～0.91 and 0.48～0.79, respectively. The Jaccard similarity index(〖WTBX〗Cj〖WTBZ〗) of low water area-deep water area was the highest (0.667) while that of deep water area-woods was the lowest (0.016), and the Bray-Curtis index (〖WTBX〗CN〖WTBZ〗) of woods-vegetable land was the highest (0.006 8) while that of low water area-deep water area was the lowest (0.001 4). Increment from population and urbanization development brought about the loss of avian habitats in Caohai, and disturbance from human had impacts on the avian diversity. Eco-compensation measures were recommended to practice for better management in Caohai. References | Related Articles | Metrics

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Influencing factors of water transparency in landscape water bodies of parks and public green space, Shanghai YU Li-fan, SHI Miao-xiao, DA Liang-jun, YAN Xiao, YIN Jun-guang 2012, 2012 (4):  112-119.  Abstract ( 2571 )   PDF (1348KB) ( 2394 )   Save Taking 107 landscape water bodies in 90 parks and public green space of Shanghai as study objects, the relationship between water transparency and light attenuation coefficient was quested and therefore the main influencing factors upon water transparency were studied in this paper with application of outdoor investigation and indoor experiments. The results showed that: (1) the water transparency generally stayed at a low level with mean value of (0.54±0.24) m, and more than 98.31% water bodies were below 1.0 m; (2) there was a significant negative correlation between water transparency and light attenuation coefficient, which could be shown as Kd=0.017+〖SX(〗1.12〖〗ST〖SX)〗; (3) the suspended matter was the main influencing factors of transparency in landscape water bodies of parks and public green space in Shanghai. The total phosphorus and ammonia-N in the water affected water transparency out of their nutrient control over phytoplankton. The results offer a new measurement to assess the water quality, especially the water transparency of landscape water bodies scientifically, and hence will provide a scientific basis for the improvement of water environments, the establishment of aquatic vegetation and the maintenance and management of water bodies. References | Related Articles | Metrics

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Evaluation of ecological forest ecosystem services in Zhenhai District, Ningbo SHEN Chen-chen, YIN Jun-guang, ZHANG Jing, HUANG Yan-cheng, DA Liang-jun 2012, 2012 (4):  120-130.  Abstract ( 2569 )   PDF (1831KB) ( 2545 )   Save The concentrations of microbe content, negative-ion and the temperatures, humidities, noises were monitored in 9 sample points in Zhenhai ecological forest belts, combined with the quantitive analysis of pollutants contents and dust accumulation abilities in the leaf samples. Based on these data and by applying the methods of substitution of the expenses, and shadow project, the ecological services of forest ecosystem in Zhenhai District were evaluated. The results showed that in 2008, the total value of ecological forest ecosystem services in Zhenhai District was 1.652 8×108 yuan. The sequence of the service function values was as follows: atmosphere environmental purification＞water storage＞temperature regulation＞C fixation and O2 release＞biodiversity conservation＞provision of forest products＞soil conservation soil conservation. Two factors which influence the evaluation of the ecological forest ecosystem services were proposed, including the characteristics of plant communities and the selection of assessment indexes and methods. References | Related Articles | Metrics

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Nutrient contents of dominant seagrass species and their affecting factors in Hainan Province YU Zhi-qin, DENG Hong, WU Ke-wei， DU Jing， MA Min 2012, 2012 (4):  131-141.  Abstract ( 3051 )   PDF (730KB) ( 2574 )   Save Nutrient (N, P and Fe) contents of 〖WTBX〗Enhalus acoroides, Cymodocea rotundata〖WTBZ〗 and 〖WTBX〗Thalassia hemperichi〖WTBZ〗 dominated in the seagrass beds in Hainan were studied in this paper. The results indicated that nutrient uptake by inter-tidal seagrass was influenced by both N, P in seawater and chemical characteristics of sediments (N, P, TOC and Fe). Phosphorus concentration of seagrass, which was more sensitive to water and sediment than that of nitrogen, was positively correlated with the level of P in seawater and TOC and total Fe in sediment. Enhanced nutrient level induced by human activates has exerted imbalance of N and P uptake in seagrass, with the leaf N:P of Xincungang （21.73）>Li′an （14.25）> Wenchang （9.53）≈ Tanmen （10.29）. The fact that leaf N:P had strong correlation with DTN:DIP in seawater has indicated the influence of eutrophication on the imbalance of nutrient uptake in seagrass. References | Related Articles | Metrics

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Preliminary study on dynamics of evergreen broad-leaved forest in Eastern Ningbo using 3S methods YUAN Jing, WANG Xi-hua 2012, 2012 (4):  142-148.  Abstract ( 2440 )   PDF (691KB) ( 2165 )   Save This paper classified land use and vegetation types of Ningbo with Landsat remote sensing data of 6 times (1974～2009) using 3S methods, extracted the regions of different vegetation types which turn into evergreen broad-leaved forest in each period and calculated transformation rate of every type for evergreen broad-leaved forest. Results showed that physical succession rules and economic benefits are the main causes of evergreen broad-leaved forest dynamic changes in the past 37 years. It is likely to conversed with coniferous and broad-leaved mixed forest and evergreen and deciduous broad-leaved mixed forest without considering human influence. On this basis, we measured the distance between vegetation types turned into evergreen broad-leaved forest in each period and the type remained evergreen broad-leaved forest in the same period, calculated total average value of five periods, and ordered them by vegetation types: coniferous and broad-leaved mixed forest>evergreen and deciduous broad-leaved mixed forest>bamboo>coniferous forest>tea plantations and orchards>shrub>farmland, it is found that seed spread and land use history are key factors which affected direction of degraded evergreen broad-leaved forest community’s secondary succession. References | Related Articles | Metrics

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Distribution characteristics of chlorophyll a and its relationship with phytoplankton density in Lake Dianshan HU Xue-qin, WANG Qiang, MA Ming-rui, XU Chun-yan, YOU Wen-hui 2012, 2012 (4):  149-156, 163.  Abstract ( 3265 )   PDF (1205KB) ( 2265 )   Save Ｔｈｉｓ ｐａｐｅｒ ｒｅｐｏｒｔｅｄ ｔｈｅ ｈｏｒｉｚｏｎｔａｌ ａｎｄ ｔｅｍｐｏｒａｌ ｄｉｓｔｒｉｂｕｔｉｏｎ ｐａｔｔｅｒｎ ｏｆ ｃｈｌｏｒｏｐｈｙｌｌ ａ ａｎｄ ｐｈｙｔｏｐｌａｎｋｔｏｎ ｄｅｎｓｉｔｙ ａｓ ｗｅｌｌ ａｓ ｔｈｅｉｒ ｒｅｌａｔｉｏｎｓｈｉｐｓ， ｗｈｉｃｈ ｗｅｒｅ ｂａｓｅｄ ｏｎ ｔｈｅ ｅｃｏｌｏｇｙ ｉｎｖｅｓｔｉｇａｔｉｏｎ ｃａｒｒｉｅｄ ｏｕｔ ｉｎ Ｌａｋｅ Ｄｉａｎｓｈａｎ ｆｒｏｍ  Ｏｃｔｏｂｅｒ ２００９ ｔｏ Ｓｅｐｔｅｍｂｅｒ ２０１０． Ｔｈｅ ｒｅｓｕｌｔｓ ｓｈｏｗｅｄ ｔｈａｔ：（１） Ｔｈｅ ｃｈｌｏｒｏｐｈｙｌｌ ａ ｃｏｎｃｅｎｔｒａｔｉｏｎ ｗａｓ ｒａｎｇｅｄ ｆｒｏｍ ０．８７ ｔｏ １３９．４３ｍｇ／ｍ３  ｗｉｔｈ ａ ｍｅａｎ ｏｆ（２５．３５±２．７１）ｍｇ／ｍ３；（２） Ｔｈｅ ｐｈｙｔｏｐｌａｎｋｔｏｎ ｄｅｎｓｉｔｙ ｗａｓ ｒａｎｇｅｄ ｆｒｏｍ ０．４０ ｔｏ ２１０．９１×１０６ｉｎｄ／Ｌ ｗｉｔｈ ａ ｍｅａｎ ｏｆ （１０．０２±２．４５）×１０６ｉｎｄ／Ｌ；（３） Ｉｎ ｔｈｅ ｔｅｍｐｏｒａｌ ｓｃａｌｅ，ｂｏｔｈ ｃｈｌｏｒｏｐｈｙｌｌ ａ ａｎｄ ｐｈｙｔｏｐｌａｎｋｔｏｎ ｄｅｎｓｉｔｙ ｗｅｒｅ ｈｉｇｈｅｒ ｉｎ ｓｐｒｉｎｇ ａｎｄ ｓｕｍｍｅｒ ａｎｄ ｌｏｗｅｒ ｉｎ ａｕｔｕｍｎ ａｎｄ ｗｉｎｔｅｒ． Ｉｎ ｔｈｅ ｈｏｒｉｚｏｎｔａｌ ｓｃａｌｅ,  ｔｈｅｙ ｗｅｒｅ ｈｉｇｈｅｒｉｎ ｎｏｒｔｈｅｒｎ ｓｉｔｅｓ ｔｈａｎ ｉｎ ｓｏｕｔｈｅｒｎ ｓｉｔｅｓ；（４） Ｃｏｒｒｅｌａｔｉｏｎ ａｎａｌｙｓｉｓ ｓｈｏｗｅｄ ｔｈａｔ ｃｈｌｏｒｏｐｈｙｌｌ ａ ａｎｄ ｐｈｙｔｏｐｌａｎｋｔｏｎ ｄｅｎｓｉｔｙ ｗｅｒｅ ｓｉｇｎｉｆｉｃａｎｔｌｙ ｃｏｒｒｅｌａｔｅｄ （Ｓｉｇ．≤０．０１）， ａｎｄ Ｃｈｌｏｒｏｐｈｙｔａ，Ｃｙａｎｏｐｈｙｔａ，Ｂａｃｉｌｌａｒｉｏｐｈｙｔａ ａｎｄ Ｃｒｙｐｔｏｐｈｙｔａ′ｓ ｄｅｎｓｉｔｉｅｓ′ ｃｏｎｔｒｉｂｕｔｉｏｎｓ ｔｏ ｃｈｌｏｒｏｐｈｙｌｌ ａ ｃｏｎｃｅｎｔｒａｔｉｏｎ ｗｅｒｅ ｈｉｇｈｅｒ ｔｈａｎ ｏｔｈｅｒ ｃａｔｅｇｏｒｉｅｓ．Ａｎｄ ｔｈｅ ｃｏｎｔｒｉｂｕｔｉｏｎｓ ｖａｒｉｅｄ ｗｉｔｈ ｓｅａｓｏｎｓ. References | Related Articles | Metrics

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Research on the effects of weed nitrogen and phosphorus enrichment in natural approximating ecological agro-ditches of Dianchi Lake basin HE Ming-zhu, XIA Ti-yuan, LI Li-chi, DA Liang-jun 2012, 2012 (4):  157-163.  Abstract ( 2746 )   PDF (711KB) ( 2269 )   Save This paper quantified the weed and species removal effect of N&P respectively, and definite the yearly absorption and removal effect of N&P in farmland soil and runoff by weed in the natural approximating ecological agro-ditches in Dianchi Lake basin, to provide the evidence of water eutrophication comprehensive treatment in agro-diffused pollution by cutting N&P effectively and source control. The result proved: ① There is a great difference of N&P enrichment among different weeds, in the same or different species of different periods; ② the main phenomenon of N&P enrichment of natural approximating weed plant is N limitation (N〖DK〗∶P<14); ③ there is positive relationship between N&P nutrient absorption and the weed biomass in natural approximating ecological agro-ditch of farmland, and the whole year total amount of N&P in the basin were N (37.86±9.9) kg/hm2, P (27±1.19) kg/ha, which were much lower than the maximum of N 113.16 kg/ha, P 10.14 kg/hm2. References | Related Articles | Metrics

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Non-point source pollution management oriented urban watershed division method in tidal plains Lv Yong-peng, YANG Kai, CHE Yue, JIN Yan, XU Qi-xin 2012, 2012 (4):  164-172, 189.  Abstract ( 2521 )   PDF (2824KB) ( 2714 )   Save This paper analyzed the characteristics of urban watershed in tidal plains. Non-point source pollution management oriented urban watershed division method in tidal plain was proposed from three aspects of spatial scale, runoff mechanism and management intensity. Lingang watershed of Shanghai in China was taken as a case. The results showed that Lingang watershed can be divided into one first-class sub-watershed, 13 second-class sub-watersheds and 137 third-class sub-watersheds. The spatial distribution of the second-class sub-watersheds and function divisions are almost the same, which indicates the proposed method is operable. References | Related Articles | Metrics

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Response to the anthropogenic impact on heavy metals in the sediment core from the Swan oxbow in the middle Yangtze River HE Rong, DENG Bing, DU Jin-zhou, WU Ying 2012, 2012 (4):  173-180.  Abstract ( 2598 )   PDF (1297KB) ( 2967 )   Save The chronological dating of the sediment core from the Swan oxbow of the middle Yangtze River in April 2007 was determined by the combination of excess 210Pb (210Pbex) profile and the sedimentary characteristics. Environmental changes in the upper and middle reach of the Yangtze River in China in the last 50 years have been recorded by the concentration of elements (K, Ca, Na, Mg, Al, Fe, Mn, Ti, Cr, Cd, V, Zn, Pb, Cu, Ni, Co, Cs, U, Ga, Ba, Sr) in the sediment core detected by ICP-AES and ICP-MS. The results demonstrated that the regional environment is subjected to the human activities and the channel migration of the Yangtze River. During 1950s~1990s, low concentration and scale of the metal/aluminum variation suggested that the elements was mainly controlled by the weathering of river basin and the sedimentary environment. Since 1990s, substantially increasing of heavy metals suggested heavier pollutant of the river basin resulting from both increasing of industrialization and hydraulic engineering construction of the river basin. The decreasing of sediment load of the Yangtze River from hydraulic construction practices in recent years potentially diminished self-purification of river, thus negatively impact on environment of river basin. References | Related Articles | Metrics

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Effect of the deep waterway project on the salinities in the north passage of the Changjiang Estuary FAN Zhong-ya, GE Jian-zhong, DING Ping-xing, PAN Ling-zhi 2012, 2012 (4):  181-189.  Abstract ( 2842 )   PDF (5323KB) ( 2574 )   Save Unstructured-grid Finite Volume Coastal and Ocean Model (FVCOM) has been applied on the north passage, Changjiang Estuary, to study the salinity distribution and its variations under the impacts of different phases of the deep waterway project (DWP). Driven by the same forcings of freshwater discharge, tide and wind, the spring-neap-averaged and typical tidal moment’s salinity distributions under different phases of DWP are simulated and analyzed The modeling results show that the isohaline has been significantly pushed downstream after Phase I, and continued moving eastward after Phase II. At the same time, the controlling region of isohaline 1‰~5‰ has smoothly increased and the vertical mixing effects seem be weakened from the middle to eastern parts of shipping channel. Strong stratification is revealed along the deep channel. After the Phase III, the controlling region of isohaline 1‰~5‰ still increases with the upstream direction. The onshore saltwater intrusion has significantly intensified as the increased baroclinic gradient force due to deepened eastern channel. References | Related Articles | Metrics

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Upgrades of the integrated visualized storm surge forecasting system in the Changjiang Estuary LI Cheng, GE Jian-zhong, DING Ping-xing 2012, 2012 (4):  190-195.  Abstract ( 2169 )   PDF (2364KB) ( 2658 )   Save This study focuses on the upgrade of an integrated storm surge forecasting system for the Changjiang Estuary with development tools such as VB.NET, Intel Fortran, etc. The forecasting efficiency with wave consideration has significantly improved by the implementation of SWAN parallel computation. Hydrodynamic model could provide much faster forecasting with the optimization and modularization of the source code. New software interface was designed to improve the compatibility and stability. The comparison between the original and upgraded version is given with 5 storm surge simulation, with an aim to show the system improvement on forecasting efficiency and precision. It shows the model precision of upgraded version is guaranteed. The efficiency is quantitatively increased by 68% and 60% with consideration and neglecting of wave effect, respectively. References | Related Articles | Metrics