Jiangxi Academy of Environmental science

Nanchang, China

Jiangxi Academy of Environmental science

Nanchang, China
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Zhu P.,Hohai University | Li H.-M.,Jiangxi Academy of Environmental science
Journal of Molecular Structure | Year: 2011

A novel 2D layer complex [Mn(TPA)Cl(H2O)]n (1) has been synthesized by two methods through the reaction of MnCl2 and TPC or TPA under hydrothermal conditions and characterized by single crystal X-ray diffraction, elemental analysis, infrared spectrometry (IR), powder X-ray diffraction (XRD) and thermogravimetric analysis (TGA), where heterocyclic carboxylic acid ligand TPA = 2-(5-(pyridin-2-yl)-2H-tetrazol-2-yl)acetic acid, TPC = 2-(5-(pyridin-2-yl)-2H-tetrazol-2-yl)acetonitrile. The distorted octahedral Mn(II) centers are bridged by carboxylic O atoms resulting in the formation of a 1D chain. Then the 1D chains are connected with each other through TPA ligands into a 2D (3,3)-connected topology framework. The H-bonding interactions extend the complex into a three-dimensional network, and such weak interactions further stabilized the complex. Furthermore, solid-state fluorescence spectrum of complex 1 exhibits intense broad emissions at 396 nm at room temperature, which is red-shifted by 21 nm relative to that of free ligand TPA. © 2011 Elsevier B.V. All rights reserved.

Liu Q.S.,Jiangxi University of Science and Technology | Tang H.F.,Jiangxi Academy of Environmental science | Fang H.,Jiangxi University of Science and Technology
Advanced Materials Research | Year: 2011

An apparatus to measure compressive creep in carbon cathode materials has been developed. Short-time creep were measured at 30°C, 965°C and during aluminum electrolysis at 965°C. The creep strain increases with stress, indicating that the creep behavior is of the stress dependency. The ranking from low to high creep was at 30°C<965°C

Zhu G.,CAS Wuhan Institute of Hydrobiology | Zhu G.,University of Chinese Academy of Sciences | Li W.,CAS Wuhan Institute of Hydrobiology | Li W.,University of Chinese Academy of Sciences | And 3 more authors.
Hydrobiologia | Year: 2012

Little is known about the mechanical resistance response of submerged macrophytes to floods. An experiment was conducted to investigate the plant growth, root anchorage strength, and stem tensile properties of five submerged macrophytes under three initial water levels (1.0, 2.5, and 4.0 m) with four water level fluctuation speeds (0, 5, 15, and 25 cm d -1). Our results demonstrate that the biomass, relative growth rate, root anchorage strength, and stem tensile properties of the five species decreased with increasing initial water level, suggesting that deep water can inhibit plant growth and decrease their mechanical resistance. Floods weakened the stem tensile properties and strengthened the root performances of Myriophyllum spicatum, Hydrilla verticillata, and Potamogeton malaianus in shallow water. However, floods induced opposite mechanical resistance responses from plants in deep water, indicating a possible trade-off between stem breakage and uprooting under flooding conditions. M. spicatum, Ceratophyllum demersum, and P. malaianus were more tolerant of deep water and flood intensity than Potamogeton maackianus and H. verticillata, as indicated by their larger biomass, plant heights, stem tensile properties, and root anchorage strength. This is the first article that mechanically explains the competitive capability and survival potential of submerged macrophytes to water depth and flood intensity. © 2012 Springer Science+Business Media B.V.

Zhu G.,CAS Wuhan Institute of Hydrobiology | Zhu G.,Henan Normal University | Cao T.,CAS Wuhan Institute of Hydrobiology | Zhang M.,Jiangxi Academy of Environmental science | And 2 more authors.
Hydrobiologia | Year: 2014

Decline of submersed macrophytes has occurred in eutrophic lakes worldwide. Little is known about effects of nutrient enrichment on biomechanical properties of submersed macrophytes. In a 30-day experiment, Myriophyllum spicatum was cultured in aquaria containing two types of sediment (mesotrophic clay vs. fertile loam) with contrasting water NH4 + concentrations (0 vs. 3.0 mg L-1 NH4-N). The plant growth, shoot and root morphology, stem biomechanical properties, and stem total nonstructure carbohydrates content (TNC) were examined. The NH4 +-enriched water, particularly combined with the fertile sediment, caused adverse effects on M. spicatum as indicated by reductions in the growth, stem biomechanical properties (tensile force, bending force and structural stiffness), and TNC content. These results indicate that increased sediment fertility and water NH4 +-enrichment made the plant more fragile and vulnerable to hydraulic damage, particularly for the upper stem, implying that M. spicatum was prone to uprooting and fracture by hydraulic force, and the broken fragment from parent shoot of M. spicatum might have low-survival potential due to its low-TNC content. This may be a mechanical aspect for the decline of submersed macrophytes and makes it more difficult to restore submersed vegetation in the eutrophic lakes. © 2014 Springer Science+Business Media Dordrecht.

Zhu G.,CAS Wuhan Institute of Hydrobiology | Zhu G.,Henan Normal University | Zhang M.,Jiangxi Academy of Environmental science | Cao T.,CAS Wuhan Institute of Hydrobiology | Ni L.,CAS Wuhan Institute of Hydrobiology
Environmental Earth Sciences | Year: 2015

Submerged macrophytes mainly distribute in the wind-protected littoral zones, rather than continuously distribute around the lake due to mechanical damage by strong wave. However, it is unknown how the biomechanical properties, the key targets against mechanical stress, contribute to its survival and distribution in natural aquatic ecosystem. In this study, the distribution, plant growth, and leaf biomechanical and morphological traits of different segments of Vallisneria natans were examined at 25 sites with three wind strength [sites exposed to strong ES wind (HW), sites exposed to moderate ES wind (MW) and sites sheltered by lakeshore with weak wind disturbance], in Lake Erhai, of Yunnan Province, China. Results showed that V. natans mainly distributed in the wind-protected eastern and northern littoral zones within 5 m water depth. The smallest plant growth, strongest and least flexible leaves were at MW, indicating that V. natans is prone to dominate the littoral zones exposed to strong but short wave. Additionally, the high plant growth and relatively stronger and less flexible leaves at HW suggested that the maximization of photosynthesis was at the cost of reduced biomechanical properties and increased drag forces from similar waves, which were unfavourable to complete their life cycles and ultimately reduce the survival and distribution of V. natans under strong wave disturbance. The significant associations between the biomechanical and morphological traits may trigger trade-offs between the mechanical resistance and other plant functions, such as photosynthesis, ultimately determining survival and distribution of submerged macrophytes in natural aquatic ecosystems. © 2015, Springer-Verlag Berlin Heidelberg.

Zhang M.,CAS Wuhan Institute of Hydrobiology | Zhang M.,Jiangxi Academy of Environmental science | Wang Z.,American Hach Company | Xu J.,CAS Wuhan Institute of Hydrobiology | And 4 more authors.
Chemosphere | Year: 2011

The heavy bloom of cyanobacteria is a disastrous consequence of freshwater eutrophication, and the bloom is highly toxic due to its secondary metabolites called microcystins (MCs). The release of organic substances from dense blooms causes an increase in NH4+ and decrease in oxygen in lake water. In the present study, the dynamics of physio-biochemical responses of five aquatic macrophytes to MCs and NH4+ stresses in Meiliang Bay were evaluated. The bay is one of the most seriously eutrophized areas dominated by the toxic cyanobacteria of Lake Taihu, China. The results demonstrate that aquatic macrophytes in Meiliang Bay are subjected to successive external stresses. From January to May, they are subjected to high NH4+ stress (>0.56mgL-1), whereas from June to September or during dense blooms, the macrophytes experience both MC proliferation and moderate NH4+ toxicity (>0.3mgL-1). In August, high NH4+ stress occurs along with hypoxia stress, whereas from September to December, the macrophytes experience moderate NH4+ stress, causing a serious imbalance in C-N metabolism and oxidative stress. Between the two aquatic plant life forms, floating-leaved plants are more resistant to the stresses of eutrophication than are submersed plants. Elevated MCs in the water column can aggravate oxidative stress and suppress the soluble protein contents of aquatic plants. High NH4+ in the water causes severe C and N imbalance in submersed macrophytes because of considerable carbon consumption for free amino acid synthesis. The superoxide dismutase activities of submersed macrophytes are suppressed by low light penetrating the eutrophic water, which might impair the antioxidative function of the plants. The findings of this study provide mainly field evidence that reveals the physical, chemical, and biological stresses on aquatic plants in bloom-prevailed eutrophic lakes. © 2010 Elsevier Ltd.

Cao T.,CAS Wuhan Institute of Hydrobiology | Ni L.,CAS Wuhan Institute of Hydrobiology | Xie P.,CAS Wuhan Institute of Hydrobiology | Xu J.,CAS Wuhan Institute of Hydrobiology | Zhang M.,Jiangxi Academy of Environmental science
Freshwater Biology | Year: 2011

Increased ammonium concentrations and decreased light availability in a water column have been reported to adversely affect submersed vegetation in eutrophic waters worldwide. We studied the chronic effects of moderate enrichment (NH 4-N: 0.16-0.25mgL -1) on the growth and carbon and nitrogen metabolism of three macrophytes (Ceratophyllum demersum, Myriophyllum spicatum and Vallisneria natans) under contrasting light availability in a 2-month experiment. The enrichment greatly increased the contents of free amino acids and nitrogen in the shoot/leaf of the macrophytes. This indicates that was the dominant N source for the macrophytes. Soluble carbohydrate contents remained relatively stable in the shoot/leaf of the macrophytes irrespective of the treatments. Under ambient light, the starch contents in the shoot/leaf of C. demersum and M. spicatum increased with enrichment, whereas V. natans did not exhibit any change. The starch contents decreased in C. demersum, increased in M. spicatum and remained unchanged in V. natans after the combined treatment of enrichment and reduced light. The enrichment did not affect the growth of the three macrophytes under the ambient light. However, it did suppress the growth of C. demersum and M. spicatum under the reduced light. The results indicate that a moderate enrichment was not directly toxic to the macrophytes although it might change their viability in eutrophic lakes in terms of the carbon and nitrogen metabolism. © 2011 Blackwell Publishing Ltd.

Chang J.-J.,CAS Wuhan Institute of Hydrobiology | Chang J.-J.,Yunnan University | Wu S.-Q.,CAS Wuhan Institute of Hydrobiology | Wu S.-Q.,Jiangxi Academy of Environmental science | And 4 more authors.
Ecological Engineering | Year: 2013

Nitrogen removals from nitrate-laden wastewater using two replicated, pilot-scale integrated vertical-flow constructed wetland systems (IVCWs) were investigated. Seasonal variation of the treatment performance and the critical environmental influencing factors was analyzed. Over a study period of 14months, the system was able to achieve moderate nitrogen removals with mean removal efficiencies of 56.2% and 55.1%, mass removal rates of 762.1mgm-2d-1 and 819.7mgm-2d-1 for nitrate and TN, respectively, under a relatively low influent COD:N ratio of 1.67. Water temperature and DO concentration were the primary factors affecting nitrogen removal. The seasonal order of nitrogen removal efficiency was: summer>autumn>spring>winter. Predictive models with statistical confidence were developed for nitrogen removals employing on-line parameters as indicators. © 2013 Elsevier B.V.

Zhu B.H.,Jiangxi Science and Technology Normal University | Zhu D.Q.,Jiangxi Academy of Environmental science
Advanced Materials Research | Year: 2013

The forest is considered as a precious and indispensable nature resource, but forest fire which can destroy forest resource safety and threaten human-living environment is considered as one of the severest disasters. How to monitor and collect information of forest fire at any time, it is a difficult problem for Forest Fire Prevention Departments to urgently solve. With the development of sensor technology, MEMS and wireless communications, wireless sensor network (WSN) has wide application in all kinds of fields. In order to prevent forest fire occurrence, this paper designs a monitoring system for forest fires based on wireless sensor network and GPRS network. The system gives the hardware design of wireless sensor nodes and software implementations, and chooses CC2530 to achieve the process of data acquisition and transmission, then sends the data through GPRS module to the remote monitoring center. By means of WSN and GPRS network, the system accomplishes data acquisition and long distance transmission. © (2013) Trans Tech Publications, Switzerland.

Liu X.,Huazhong University of Science and Technology | Li S.,Huazhong University of Science and Technology | Li M.,Huazhong University of Science and Technology | Li M.,Jiangxi Academy of Environmental science
Plasma Science and Technology | Year: 2013

A simple negative ion mobility spectrometer (IMS) is designed and used to investigate the factors that influence the number and efficiency of electrons generated by the needle-ring pulsed corona discharge electron source. Simulation with Ansoft Maxwell 12 is carried out to analyze the electric field distribution within the IMS, and to offer the basis and foundation for analyzing the measurement results. The measurement results of the quantities of electrons show that when the drift electric field strength and the ring inner diameter rise, both the number of effective electrons and the effective electron rate are increased. When the discharge voltage becomes stronger, the number of effective electrons goes up while the effective electron rate goes down. In light of the simulation results, mechanisms underlying the effects of drift electric field strength, ring inner diameter, and discharge voltage on the effective electron number and effective electron rate are discussed. These will make great sense for designing negative ion mode IMS using the needle-ring pulsed corona discharge as the electron source.

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