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25 September 2013, Volume 2013 Issue 5 Previous Issue    Next Issue

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Numerical simulation of the longest continuous days unsuitable for water intake in the Dongfengxisha reservoir of the Changjiang Estuary ZHU Jian-rong, WU Hui 2013, 2013 (5):  1-8， 26.  Abstract ( 1754 )   PDF (3333KB) ( 2104 )   Save An improved three dimension numerical model of saltwater intrusion in the Changjiang Estuary was applied to this numerical simulation. The model was validated with the salinity observed in 2007—2008 at the 10 hydrological sites, and the results showed that the model calculated salinity are well consistent with the observed ones. We considered the extremely drought year 1978—1979 as a hydrological calculation year, adopted the observed topography in 2008, and considered the effects of tide, wind stress and mixing in the model. The measured daily river discharge at the Datong station was modified by the Three Gorges Project, the eastern water diversion project from the South to the North, and the water intake and drain along the river. The conclusion is that the longest continuous days unsuitable for water intake in the Dongfengxisha reservoir are 26 days. This important parameter has been adopted in the build of the reservoir, providing scientific and technological support for the construct of ecological Chongming island and the ensure of freshwater resource safety. References | Related Articles | Metrics

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Temporal and spatial variation law of momentum coefficients in the Yangtze Estuary YANG Yun-ping, LI Yi-tian, HAN Jian-qiao 2013, 2013 (5):  9-17.  Abstract ( 1887 )   PDF (2735KB) ( 2095 )   Save Based on the measured data of Xiaoshan to Yangtze Estuary reach, the temporal and spatial distribution law of momentum coefficients was studied. Then the difference of coefficients in beaches and deep trough was obtained and the empirical curve was established. The results showed that the momentum coefficients in wet seasons were higher than that in dry seasons in the estuary, while the law was totally contrary in the North Passage. The coefficients in spring tidal were higher than those in neap tidal from Xiaoshan to Shihuaxia in wet seasons. In dry seasons, the coefficients in spring tidal were higher than those in neaps tidal from Xiaoshan to Langshashan and the law was contrary from Xuliujing to Shihuaxia. The tidal limit was the boundary that the downstream coefficients of it were increasing. The coefficients in North Channel were higher than those in South Channel and the coefficients in North Passage were higher than those in South Passage. The main reason of this phenomenon was the temporal and spatial variation of driving forces of runoff and tide. The water depth of 15 m was thinking as the demarcation of point bars and deep troughs. The momentum coefficients increased with the increase of the water depth in the point bars and the coefficients didn’t change much in the deep troughs. The empirical curve was also established. References | Related Articles | Metrics

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Study on the quantitative relationship of the location of the tidal current limit and the river discharge in the Changjiang Estuary HOU Cheng-cheng, ZHU Jian-rong 2013, 2013 (5):  18-26.  Abstract ( 2523 )   PDF (4764KB) ( 2598 )   Save The Changjiang Estuary is a tidal estuary with the interaction of river discharge and tidal current. The tidal variation results in the change of flow state in the river. By designing a high resolution numerical model, and based on the calculations of water flux along the river transverse sections, the Changjiang River tidal current limits were obtained in various guarantee rate river discharges in dry and flood seasons. The tidal current limit is between Taiyang island (located at the 70 km upstream of Wuhu) and Zhengjiang hydrological station in dry seasons, and is in the range of 100 km between the middle of Taiping island (located at the upstream Jiangying) and Minzhu island in flood seasons. With the multi power fitting of the calculated results, the relationship between the location of the tidal current limit and the river discharge is y=-4×10-10x3+1×10-5x2-0.193 7x+1 232.9（R2=0.984 2） in dry season, and is y=2×10-13x3+3×10-8x2-0.007 4x+359.35（R2=0.996 9） in flood season. This result can provide a scientific basis for determining the tidal current limit of the Changjiang River. References | Related Articles | Metrics

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Responses of decomposition of Phragmites australis litter to simulated temperature enhancement in the reclamed coastal wetland GUAN Yue-zhang, LIU An-tian, ZHONG Qi-cheng, WANG Kai-yun 2013, 2013 (5):  27-34.  Abstract ( 1989 )   PDF (1319KB) ( 2276 )   Save By using open-top growth chambers (OTC) to simulate short-term warming and mesh bags,the study was carried out in the reclaimed wetland in the east Chongming tidal flat. The effects of short-term simulated warming （1.984±0.7） ℃ on the decomposition of Phragmites australis litter were studied and the changes of correlations between decomposition rate and environmental parameters were analysed.The results are as follows: ① stem decomposition rates in OTC plots and CG plots are 49.20% and 45.11%, and leaves decomposition rates are 63.52% and 58.53%, respectively, which shows that warming has increased the decomposition rates; ② stems average decomposition coefficients (K) in OTC plots and CG plots are 0.028 and 0.027,while the average decomposition coefficients of leaves are 0.093 and 0.080, respectively, which shows that the increment of leaves K is bigger than stems K; ③ the order of correlation degree between environmental factors and decomposition rate is: 1.2 m air temperature> 0～5 cm soil temperature> 0～5 cm soil moisture,and the correlation coefficient between leaves decomposition rate and 1.2 m air temperature is biggest which is 6.43%. In summary, air temperature is the key factor affecting the Phragmites australis litter decomposition; meanwhile warming not only improves litters decomposition rates, but also changes the relevance between decomposition rate and environmental factors. References | Related Articles | Metrics

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Study on the mechanism of methylene blue degradation by TiO2 photocatalyst ZHANG Dan, XU Bin, ZHU Pei-juan, LIAN Zheng-hao, ZHAO Ya-ping 2013, 2013 (5):  35-42.  Abstract ( 4169 )   PDF (2193KB) ( 4844 )   Save In order to carry out the study, the experiments of photodegradation of methylene blue under different conditions were conducted, using different kinds of free radical scavengers, such as (CH3)3OH, H2O2, KI, NaN3 and C6H4O2. The effects of these free radical scavengers were observed. The concentration of H2O2 generated during the photodegradation of methylene blue by TiO2 was also reported. And the results of these experiments indicated that the main active oxygen substances in the reaction are ·OH, O·-2 and 1O2. References | Related Articles | Metrics

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Characteristics of the avian communities at Mt. Yuntaishan of Guizhou Province, China 2013, 2013 (5):  43-52.  Abstract ( 1924 )   PDF (1408KB) ( 2182 )   Save Bird surveys were carried out at Mt. Yuntaishan in Guizhou Province from Sept. 2011 to Aug. 2012, with line transect, point-counting and mist-netting detection. A total of 94 bird species was recorded, which belonged to 33 families and 11 orders. Among the bird species recorded, 4 species were in the Grade Ⅱ national key protected list. Birds in families of Turdidae and Timaliidae were richest, and birds in families of Timaliidae and Pycnonotidae were most abundant. Alcippe morrisonia and Yuhina castaniceps were dominant species. By comparing the species, number, Shannon-Weiner Index(H), Simpson Index(D) and Pielou Index(J) among the four seasons, the results indicated that birds in spring had highest species, and lowest D  and J. Birds in summer had lowest number, and highest H, D and J. Birds in winter had highest number, and lowest species and H. The similarity index of spring-autumn avian communities was the highest while that of summer-winter was the lowest. The Bray-Curtis index of summer-winter avian communities was the highest while that of autumn-winter was the lowest. The birds at Mt. Yuntaishan were not obviously disturbed by human beings, but probably were affected by some natural factors, such as climatic zone northward excursion of China. References | Related Articles | Metrics

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Microtubular organelles in Euplotes aediculatus (Ciliophora: Hypotrichida) revealed by fluorescent labeling LIN Qin, FAN Xin-peng, SUN Lei, ZHOU Su-juan, GU Fu-kang 2013, 2013 (5):  53-60.  Abstract ( 2067 )   PDF (2646KB) ( 1772 )   Save The cortical ciliature microtubules, base-associated microtubules, the dorsal cortical microtubule structure, as well as the morphogenesis of the cortical ciliature microtubules in Euplotes aediculatus were analyzed with FLUTAX (fluorescence taxoid) and anti-α-tubulin antibody immuno-fluorescence labeling. The results indicate that the dorsal cortical network which is called silver-line system morphologically associates with microtubular cytoskeleton. Moreover, differing from other Euplotes, The morphogenesis mode of the adoral ciliature microtubules and dorsal cortex ciliature microtubules in the proter of E. aediculatus represent a distinct morphogenesis mode which might be a referable basis for species differentiation. Additionally, anti-α-tubulin antibody immuno-fluorescence labeling shows dorsal cortex network and the early frontal-ventral-transverse cirri primordia more clearly comparing with fluorescently labeling by FLUTAX. This might suggest the tubulin element is different between cell dorsal cortex surface network and other microtubular structures, and the tubulin element may change gradually as the assembling and maturing of cortical ciliature microtubule in sequential morphogenesis stages. References | Related Articles | Metrics

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Crosslinking of decellularized bovine pericardium matrix by procyanidins: mechanical properties, stability and hemo-compatibility MA Bing, ZHAI Wan-yin, ZHANG Jia-min, SUN Xiao-ning, ZHU Zi-yan, ZHANG Hong-feng, CHANG Jiang 2013, 2013 (5):  61-70, 79.  Abstract ( 1933 )   PDF (5030KB) ( 2522 )   Save In this study, decellularized bovine pericardium matrix (dbpECM) was cross-linked by using PC at series concentrations. Mechanical properties, stability and hemo-compatibility of PC-crosslinked dbpECM (PC-dbpECM) were investigated. The results show that the tensile strength of the PC-dbpECM which crosslinked by the 2.5 mg/mL PC is increased from 29.1 MPa to 51.3 MPa with the elastic modulus roughly at basic level. Resistance of PC-dbpECM to collagenase hydrolysis is equivalent to that of GA-crosslinked. When PC-dbpECM soaked in D-Hanks solution, only the excessive non-crosslinked PC released within a week, leaving the crosslinked PC stable all the experiment period. PC crosslinked dbpECM (1 mg/mL) can effectively inhibit calcification in vitro. Both PC- and GA-dbpECM have ideal hemo-compatibility, but the PC cross-linking is superior to that of GA. The rate of platelet adhesion on the surface of 2.5 mg/mL PC crosslinked dbpECM (7.8%) was significantly lower than that of non-crosslinked group (26.1%) and the GA crosslinked group (36.6%), indicating that PC-dbpECM has low coagulation spotential. These data suggest that PC-dbpECM has good mechanical properties, stability and hemo-compatibility, suitable for preparing biological heart valves. References | Related Articles | Metrics

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An exploratory study on identification means Ulva linza from floating green algae CHEN Bin-bin, MA Jia-hai, SHIN Jong-Ahm, GAO Song 2013, 2013 (5):  71-79.  Abstract ( 2032 )   PDF (1031KB) ( 2084 )   Save To study on morphological characteristics of \textit{Ulva linza} from floating green algae, we selected specimens with the typical features of \textit{U. linza. }Only 4 specimens from 25 samples were determined as \textit{U. linza }from the morphological characteristics results. The molecular biology research by means of nuclear-encoded ITS sequences analysis was also carried out. Fifteen floating specimens with characters of \textit{U. linza} clustered into the LPP (\textit{U. linza-procera-prolifera}) complex group including the attached species DF05 from Jiangsu Province, QD03 from Shandong Province and XS01, XS02 from Zhejiang Province. The floating green algae from Rudong inland river and coastal pool of Sheyang were included in LPP complex as well. \textit{U. flexuosa} group included two specimens that just were fixation growth algae from Fujian Province. \textit{U. compressa} group had four specimens, and they all were floating green algae. A great disparity existed between the morphological characteristics and the molecular results. Identification of \textit{U. linza} and other floating green algae based on either morphology or ITS sequence unilaterally was not reliable. Almost all of floating green algae from the same location had certain morphological types, and they were considered to be different species by the ITS sequences analysis. The result of N-J tree and ITS data showed that the species in LPP complex and \textit{U. compressa} existed in the green tide. But\textit{ U. flexuosa }did not exist in the floating green algae in this research. References | Related Articles | Metrics

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Localization of adhesion molecule gp150 and its relationship with PKA activity in Dictyostelium discoideum YANG Chun-xia, HOU Lian-sheng 2013, 2013 (5):  80-87.  Abstract ( 1570 )   PDF (2188KB) ( 1626 )   Save Cell adhesion molecule gp150 plays an important role during post-aggregation stage of Dictyostelium discoideum development. The protein localization through antibodies against gp150 showed that gp150 distributed at different places during the various stages of development. In stream stage before aggregation, gp150 distributed uniformly in cytoplasm; after that, gp150 occupied the periphery region of multicellular aggregates in mound stage. During the slug stage of development, the expression level of gp150 in prestalk cells was much higher than that in prespore cells. In fruiting body stage, gp150 was enriched on the sporoderm of mature spores. High performance liquid chromatography was used to analyze PKA activity in wide-type KAx-3 cells and gp150 over expressed strain KAx-3:act15/lagC, and the results showed that, at the early stage of development (before 10 h development), PKA had lower activity in KAx-3 cells than that in KAx-3:act15/lagC cells. However, at the later stage of development, since the rapid accumulation of gp150, PKA showed higher activity in wide type cells than that in KAx-3:act15/lagCcells. These results suggested that there might be a feed back loop interaction between gp150 and PKA, by which the two signal proteins can cooperate and regular the growth and development of Dictyostelium discoideum. References | Related Articles | Metrics

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Dissolving behaviors of alkali metal nitrates in the mixed solvents of CH3CHOHCH2OH-H2O at 15 ℃ and 45 ℃ ZHANG Hui-ying, LI Shu-ni, ZHAI Quan-guo, OU Yang-miao, JIANG Yu-cheng, HU Man-cheng 2013, 2013 (5):  88-95.  Abstract ( 2047 )   PDF (1630KB) ( 2729 )   Save The equilibrium solubilities of alkali metal nitrates in the mixed solvents of CH3CHOHCH2OH/H2O (0~1) at 15 ℃ and 45 ℃, respectively, were studied by the of density-refractive index method on a self-made microdevice. The density and refractive index of the saturated solutions were also determined using DMA4500 densimeter and RXA170 refractive index detector at 15 ℃ and 45 ℃, respectively. The solubility and density for the saturated solutions were found to decrease with an increase concentration of 1,2-propylene glycol, while the refractive index trended to increase. The solubility data, density and refractive index of the saturated solutions have been equated for their relationship using four parameters empirical equation. The salting-out effect indicated that the alkaline metal salts were salted out by 1,2-propylene glycol, where the higher the temperature, the slightly bigger the salting-out rate. References | Related Articles | Metrics

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Investigation on chemiluminescence detection of vitamin B12 with capillary electrophoresis ZHU Jin-kun, SHU Lu, WU Min, WANG Qing-jiang, HE Pin-gang, FANG Yu-zhi 2013, 2013 (5):  96-101.  Abstract ( 1562 )   PDF (363KB) ( 2576 )   Save Based on the chemiluminescence (CL) catalysis of vitamin B12 (VB12 in luminol-H$_{2}$O$_{2}$ system, a novel capillary electrophoresis-chemiluminescence (CE-CL) method was developed for the accurate determination of this important nutrient substance. First of all, sodium hydrosulfite (Na$_{2}$S$_{2}$O$_{4})$ was found to be used as an competent reduction reagent to pre-reduce VB12(Co(III)) into VB12(Co(II)), which produced strong CL emission in the CL reaction of luminol-H$_{2}$O$_{2}$. In this process, some interfering CL noise was observed and capillary electrophoresis (CE) was taken to remove it by efficient separation. In this way, VB12 could be reduced gently and determined accurately by the catalyzed CL signal with our lab-constructed CE-CL system. The proposed CE-CL determination could be finished in 20 min with a detection limit (LOD) of 2$\times $10$^{-7}$ mol/L ($S$/$N$=3), a linear range from 6$\times $10$^{-7}$ to 6$\times$10$^{-4}$ mol/L ($r^{2}$=0.968) and a relative standard deviation (RSD) of 2.4{\%} ($n$=9). Utilizing this method, satisfactory results were obtained by testing VB12 tablets with a recovery of 97{\%}$\sim $106{\%}. Compared to previously reported CL analysis of VB12, we dealt with the interference components in pre-reducing solution for the first time to gain more reliable data with convenient operations. References | Related Articles | Metrics

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Preparation and properties study of a new type of T1-T2 dual mode MRI contrast agent GAO Li-peng, LIU Kai, LUO Chun-hua, LI Jian-qi,WANG Yi-ting, PENG Hui 2013, 2013 (5):  102-109.  Abstract ( 2357 )   PDF (1748KB) ( 2460 )   Save This paper studied the Fe3O4 @ SiO2 @ Gd2O(CO3)2 core/shell/shell NPs as a new type of T1-T2 dual model contrast agent for magnetic resonance imaging. The magnetic coupling between Gd2O(CO3)2 and Fe3O4 was modulated by the separating SiO2 layer to produce appropriate T1 and T2 signal. The Fe3O4 @ SiO2 @ Gd2O(CO3)2 NPs exhibit good biocompatibility, showing great potential for biomedical applications. References | Related Articles | Metrics

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Silver-coated silicon microchannel plates for three-dimensional lithium-ion batteries anodes WANG Fei, XU Shao-hui, ZHU Shan-shan, LOU Xue-feng, HUI Ke-shuang,YANG Ping-xiong, WANG Lian-wei 2013, 2013 (5):  110-118, 129.  Abstract ( 1976 )   PDF (2000KB) ( 2677 )   Save In this work, a three-dimensional (3-D) anode using a silver-coated Si microchannel plate (Si-MCP) as the active materials was prepared by photo-assisted electrochemical etching followed by electroless deposition. Using lithium foils as the counter electrodes, representative half-cells are fabricated and tested. In galvanostatic charge-discharge (C-D) measurements at 10 mA·g-1 between 0.02 and 1.5 V, our anode exhibits a charge capacity of 3484.7 mAh·g-1 with a coulombic efficiency close to 95.97% in the initial cycle. Based on the cyclicvoltammetry (CV) and the electrochemical impedance spectroscopy (EIS) data, the mechanism about the lithiation of Ag-coated Si-MCP was also studied. References | Related Articles | Metrics

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Simplified time domain model of full-bridge LLC resonant converter and its application XIAO Wen-ying, DONG Hai-bing 2013, 2013 (5):  119-129.  Abstract ( 2115 )   PDF (4621KB) ( 2407 )   Save Full bridge LLC resonant converter was studied, and a simplified time domain model was proposed based on the state equation of different modes and their related boundary equations based on deep analyze of time domain working mode of LLC resonant converter. Based on this model, gain curve of LLC resonant converter was deduced which is very important for the design of LLC resonant design. Using this presented model and its relating gain curve, LLC resonant tank design method based on magnetizing inductance Lm and inductance ratio h was proposed. Finally, a three-hundred-watt prototype was designed and build, simulated and experimental result verified the accuracy of the time domain model and the feasibility of the design method. References | Related Articles | Metrics

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Hypercyclicity and topological uniform descent of bounded linear operators LIU Yang, CAO Xiao-hong 2013, 2013 (5):  130-135, 143.  Abstract ( 1431 )   PDF (307KB) ( 1767 )   Save By using the property of topological uniform descent, this paper gave the judgement for an operator $A\in\overline{HC(H)}$, where $\overline{HC(H)}$ denoting the norm-closure of the class of all the hypercyclic operators on an infinite dimensional separable complex Hilbert space $H$. References | Related Articles | Metrics

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Vertex-distinguishing proper edge coloring of composition of complete graph and star YANG Fang, WANG Zhi-wen, CHEN Xiang-en, MA Chun-yan 2013, 2013 (5):  136-143.  Abstract ( 1583 )   PDF (197KB) ( 1938 )   Save Firstly, we gave an upper bound for the vertex-distinguishing proper edge chromatic number of composition of complete graph $K_{p}$ and star $S_{q}$, which is $pq+1$ for $p\geq 2,~q\geq4$. Then by constructing coloring in terms of the symmetry of regular polygons and the methods of combinatorial analysis, we obtained  respectively vertex-distinguishing proper edge chromatic numbers for composition of complete graph $K_{p}$ and star $S_{q}$ when $p=2,~q\geq4$; $p\geq3,~ q=4$; $p$ is even and $p\geq4,~q=5$; $pq$ is odd and $p\geq3,~q\geq5$. References | Related Articles | Metrics

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ETF arbitrage research on China financial markets CHEN Shi, WU Shu-jin, ZHENG Wei-an 2013, 2013 (5):  144-151.  Abstract ( 2627 )   PDF (1283KB) ( 2383 )   Save This paper first proposed a new model to describe the relationship between two paired asset prices: $a_x(t)X_t-a_y(t)Y_t=m_t+s_t\varepsilon_t,$ where $X_t$ and $Y_t$ denote the prices of two paired financial assets at time $t$, $a_x(t)$ and $a_y(t)$ the matching coefficients, $m_t$ the long-term trend, $s_t$ the standard deviation of residual, and $\varepsilon_t$ the standardized residual. When $a_x(t)$, $a_y(t)$, $m_t$ and $s_t$ are constants, the model is reduced to a kind of two-variable cointegration model. Based on this new model, the paper proposed a statistical arbitrage method for high-frequency trading using the stationary process $\{\varepsilon_t\}$. As its application, this method was used on three major ETFs in China financial markets and achieved very stable and high revenue on all three pairs. References | Related Articles | Metrics

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Application of stationary technical indicator in high-frequency trading based on MACD BAO Si, ZHENG Wei-an, ZHOU Yu 2013, 2013 (5):  152-160.  Abstract ( 5046 )   PDF (4857KB) ( 4539 )   Save In recent years, the rapid development of the high-frequency trading in the global financial market causes the extensive concern of the financial world. Because of the ``high frequency'' character, the high-frequency trading cannot be implemented by manual operation, but only with the help of computer programming trading system. Therefore, building a reasonable model of high-frequency trading strategy is necessary. MACD is a very important and commonly used technical analysis indicator in the stocks, futures, foreign currency exchange market, it is commonly used to judge the buying or selling time, and track the running trend of price of assets. In this paper, we define a new stationary technical indicator $\widehat{\rm MACD}_t$   based on MACD indicator, which is suitable for high-frequency trading strategy modeling. We also prove the stationarity of $\widehat{\rm MACD}_t$ under the hypothesis of stationarity of the increments of logarithm price process. Finally, we construct a high-frequency trading strategy based on $\widehat{\rm MACD}_t$  and test its effectiveness and profitability by using real market high-frequency data. All those put forward a new kind of thought in high-frequency trading. References | Related Articles | Metrics