钢桁架-钢筋混凝土管柱结构风致响应试验研究

大跨长悬挑钢-混凝土高柔结构的动力性状决定了其风振系数不能采用我国规范中的方法来计算。制作气弹性模型进行了动力性状、脉动风作用下位移响应、加速度响应、扭转响应、气动力稳定性等问题的相关试验,计算得到了风振系数,分析了风速、风向角、风机、周围建筑物等因素对风振系数的影响,给出了风振系数的建议值。将试验结果与其他方法计算的结果进行了对比分析,结果表明,试验结果偏大,符合风洞试验原理。研究结果为工程设计提供了基础资料,可供同类工程参考。     

离子交换纤维对金属氰络合物吸附性能的研究

采用强碱性离子交换纤维对含氰废水中主要离子铜氰络合物、锌氰络合物的吸附性能进行了研究.实验结果表明:含氰废水的pH在8～11范围内,纤维材料对金属氰络合物具有良好的吸附性能;纤维对铜氰络合物、锌氰络合物的吸附速率很快,4 min左右就可达吸附平衡;温度对铜氰络合物、锌氰络合物吸附影响不大,纤维的这些吸附特点对工业应用非常有利.     

Sulfate-reducing bacterial community shifts in response to acid mine drainage in the sediment of the Hengshi watershed,South China

Environmental Science and Pollution Research - Sulfate-reducing bacteria (SRB) are an attractive option for treating acid mine drainage (AMD) and are considered to be of great significance in the...     

Potential health risks of toxic heavy metals and nitrate via commonly consumed bivalve and vegetable species in Ho Chi Minh City,Vietnam

Environmental Science and Pollution Research - This study aimed to evaluate the health risks of cadmium (Cd), lead (Pb), inorganic arsenic (As), and nitrate exposure through the consumption of...     

Effects of modified biochar on rhizosphere microecology of rice (Oryza sativa L.) grown in As-contaminated soil

Biochar was carbon-rich and generated by high-temperature pyrolysis of biomass under oxygen-limited conditions. Due to the limitations of surface functional groups and the weakness of surface activity in the field of environmental remediation, the raw biochar frequently was chemically modified to improve its properties with a new performance. In this study, a kind of high-efficiency and low-cost amino biochar modified by nano zero-valent iron (ABC/NZVI) was synthesized and applied to paddy soil contaminated with arsenic (As). Dynamic changes of soil properties, arsenic speciations and rhizosphere microbial communities have been investigated over the whole growth period of rice plants. Pot experiments revealed that the ABC/NZVI could decrease the arsenic concentration in rice straw by 47.9% and increase the content of nitrogen in rice straw by 47.2%. Proportion of Geobacter in soil with ABC/NZVI treatment increased by 175% in tillering period; while Nitrososphaera decreased by 61 and 20% in tillering and maturity, respectively, compared to that of control. ABC/NZVI promotes arsenic immobilization in rhizosphere soil and precipitation on root surface and reduces arsenic accumulation in rice. At the same time, ABC/NZVI would inhibit Nitrososphaera which is related to ammonia oxidation process, and it would have a promising potential as soil amendment to reduce nitrogen loss probably.

     

In vivo assessment of plant extracts for control of plant diseases: A sesquiterpene ketolactone isolated from Curcuma zedoaria suppresses wheat leaf rust

As an alternative to synthetic pesticides, natural materials such as plant extracts and microbes have been considered to control plant diseases. In this study, methanol extracts of 120 plants were explored for in vivo antifungal activity against Rhizoctonia solani, Botrytis cinerea, Phytophthora infestans, Puccinia triticina, and Blumeria graminis f. sp. hordei. Of the 120 plant extracts, eight plant extracts exhibited a disease control efficacy of more than 90% against at least one of five plant diseases. In particular, a methanol extract of Curcuma zedoaria rhizomes exhibited strong activity against wheat leaf rust caused by P. triticina. When the C. zedoaria methanol extracts were partitioned with various solvents, the layers of n-hexane, methylene chloride, and ethyl acetate showed disease control values of 100, 80, and 43%, respectively, against wheat leaf rust. From the C. zedoaria rhizome extracts, an antifungal substance was isolated and identified as a sesquiterpene ketolactone based on the mass and nuclear magnetic resonance spectral data. The active compound controlled the development of rice sheath blight, wheat leaf rust, and tomato late blight. Considering the in vivo antifungal activities of the sesquiterpene ketolactone and the C. zedoaria extracts, these results suggest that C. zedoaria can be used as a potent fungicide in organic agriculture.     

气体循环条件下等离子体催化氧化吸附态苯

采用气体循环方式,对低温等离子体联合Mn Ox-Ag Ox、Co Ox-Ce Ox复合金属氧化物催化剂催化氧化吸附态的苯进行研究,主要考察了苯吸附存储量、氧化背景气体、催化剂对苯氧化性能的影响,并分析了催化剂对O3及N2O副产物产生的影响规律。研究结果表明,采用气体循环方式,有助于实现苯充分氧化为CO2。相同条件下,COx产率、CO2选择性及对O3的分解能力大小依次为:Mn Ox-Ag Ox/γ-Al2O3Co Ox-Ce Ox/γ-Al2O3γ-Al2O3。氧气背景下,气体循环75 min后,Mn Ox-Ag Ox/γ-Al2O3及Co Ox-Ce Ox/γ-Al2O3催化剂存在时,CO2选择性大于95%;气体循环90 min后,与γ-Al2O3所对应的COx产率相比,Mn Ox-Ag Ox/γ-Al2O3、Co Ox-Ce Ox/γ-Al2O3分别提高了38%、17%。FT-IR分析结果表明,等离子体催化氧化苯的主要产物为CO2、CO和H2O,副产物为少量的O3及N2O。     

施用城市污泥堆肥对土壤微生物群落结构变化的影响

在温室条件下进行了15周的盆栽实验，考察了施用城市污泥堆肥后，土壤中养分含量的变化规律，重点研究了施用城市污泥堆肥对土壤微生物群落结构变化的影响。实验发现，污泥堆肥能改善土壤养分，有机质和氮、磷含量得到显著提高。经PCR—DGGE分析，施肥1周后土壤中细菌和真菌的群落结构均发生了较大的变化。随着施肥时间的延长，细菌在富含有机质及氮、磷等养分的土壤环境下大量生长，多样性提高，其优势菌群属于γ变形菌、α变形菌和芽单胞菌；随着有机质的不断消耗，细菌的生长活性受到抑制，最终由于养分的缺乏，细菌种群多样性呈现小幅度的降低，优势菌群变为绿弯菌门、γ变形菌亚纲和厚壁菌门。对于真菌，其多样性指数在堆肥前3周逐渐提升，在第3～12周的监测中呈现相对稳定的变化趋势，优势菌群主要为座囊菌纲和散囊菌纲。     

Study of the Climate Change Impacts on Water Quality in the Upstream Portion of the Cau River Basin,Vietnam

This paper presents simulations of climate change impacts on water quality in the upstream portion of the Cau River Basin in the North of Vietnam. The integrated modeling system GIBSI was used to simulate hydrological processes, pollutant and sediment wash-off in the river basin, and pollutant transport and transformation in the river network. Three projections for climate change based on emission scenarios B1, B2, and A2 of IPCC Special Report on Emission Scenarios (SRES) were considered. By assuming that the input pollution sources and watershed configuration were constant, based on 2008 data, water quality in the river network was simulated up to the terminal year 2050. For each climate change scenario, patterns of precipitation in wet and dry year were considered. The change in annual and monthly trends for dissolved oxygen (DO), biochemical oxygen demand (BOD), and ammonium ions (NH4+) load and concentration for different portions of the watershed have been analyzed. The results of these simulations show that climate change has more impact on changing the seasonal water quality parameters than on altering the average annual load of the pollutants. The percent change and change pattern in water quality parameters are different for wet and dry year, and the changes in wet year are smaller than those in dry year.     

Trace determination of fifteen free amino acids in drinking source water via solid-phase extraction coupled with liquid chromatography tandem mass spectrometry

Environmental Science and Pollution Research - Amino acids (AAs) are important nitrogen-containing organics in water, and a large number of reports have proven that they were the precursors of many...