The loaded specimens were put in fresh water, 3.5%NaCl solution, 5.0%Na2SO4 solution, and simulated sea water with different concentrations respectively, and then the damage process under wetting and drying cycle was investigated. The ultrasonic non-metal testing technology, X-CT scanned image, free chloride and sulfate ions chemical titration were used to investigate the degradation of the marine concrete under the coupling effect of Chemistry and Mechanics. The effect of solutions, wetting and drying cycle and bending stress to the durability of marine concrete were further studied. The results indicate that different salt solution affects marine concrete at different degrees: sulfate salt is more corrosive than chloride salt, simulated seawater is similar to 5.0%Na2SO4 solution, while five-time simulated seawater is the most corrosive; wetting and drying cycle remarkably accelerates the penetration of corrosive ions, which results in the concrete damage, compared to the corrosive environment, concrete is damaged violently under the coupling effect of Chemistry-Mechanics and tensile stress has greater influence on the damage.

Nowadays, inspired by the behavior and neuronal architecture of human visual system (HVS), region of interest (ROI) detection methods are investigated by integrating several cognitive features. However, most of them are complex and time-consuming. To solve this problem, a video ROI extraction algorithm based on information theory and cognitive features is proposed in this paper. Based on the information theory, the spatial and temporal information are computed to measure the spatial and temporal content of video sequences respectively. Utilizing the visual features fusion strategy (VFFS), visual information is obtained from the combination of spatial and temporal information. Then, perceptual stimulus-response model (PSRM) is established to map the visual information to match the visual saliency. Regions with saliency scores, which are higher than a self-adaptive threshold, are regarded as ROIs. Experimental results show that the proposed scheme reduces 50% computation complexity, and can extract ROI more effective compared to Itti's method. Furthermore, the proposed ROI extraction scheme can be easily applied in the practical multimedia processing and pattern recognition system, such as video summarization.

This study was conducted to evaluate the distribution characteristics of phosphorus and its species in 14 sediments samples collected from Lake Hongfeng based on sequential extraction. Lake Hongfeng, a major drinking-water source for Guiyang City in southwestern China, is one of the largest artificial reservoirs located in a typical karstic area of the Yunnan-Guizhou Plateau. The results of this study indicate that the average percentages of DP, Al-P, Fe-P, Ca-P and OP in the lake sediments were 0.52, 6.59, 6.09, 42.85 and 40.27, respectively. The concentrations of organic phosphorus (OP) were lower than those of inorganic phosphorus (IP), which consisted mainly of calcium-bound phosphorus (Ca-P). The high concentrations of Ca-P may temporarily control the release of phosphorus from the sediments because it is a relatively stable, inert, and non-bioavailable phosphorus fraction. However, a large number of phosphate solubilizing bacteria can transform insoluble phosphate into bioavailable forms. Moreover, the concentrations of total phosphorus (TP) in the lake sediments were high; thus, the potential for the release of phosphorus from the sediments to the water column and phosphorus bioavailability were still significant. Further statistical analyses of the results revealed significant correlations between phosphorus species in sediments from the lake with two extractable principal component species (PCs) and five selectable cluster levels allowing interpretation of possible origins of phosphorus loading and the release of phosphorus. Furthermore, available remediation measures were briefly assessed for the lake with consideration of its distinctive environmental features.

In the present work, contamination and potential ecological risk of six heavy metals (Pb, Cd, Hg, As, Cu and Zn) in sediments of Aha Lake, one of the five drinking water sources for Guiyang City, were assessed based on a method which is associated with toxic-response factors of contaminants. For comparison, the two sets of reference data representing the pre-industrial and the local baseline pollution levels were employed. When the pre-industrial levels were taken as references, the accumulating coefficients on average diminished in the order of Zn > As > Hg > Cd > Cu > Pb, and the potential ecological risk descended in the order of Hg > Cd > As > Cu > Zn > Pb. When the local baseline values worked as references, the accumulating coefficients on average diminished in the order of Cd > Zn > Hg > Cu > As > Pb, and the potential ecological risk descended in the order of Cd > Hg > As > Cu > Zn > Pb. It is evident that Cd and Hg are the critical elements in terms of potential ecological hazard in Aha Lake among these six heavy metals.

This paper reports a study on distribution characteristics of phosphorus and its species in 20 sediments samples from Lakes Baihua and Aha, based on the technique of sequential extraction. Baihua and Aha, two man-made reservoirs, are key drinking-water sources. The results, compatible with local geophysical characteristics, indicate that in sediments from both lakes, the concentrations of inorganic phosphorus (IP) were higher than those of organic phosphorus (OP), and the IP consisted mainly of calcium-bound phosphorus (Ca-P), which may temporarily control phosphorus release. Moreover, the concentrations of total phosphorus (TP) in both lakes sediments were high, thus phosphorus release potential and bioavailability were highly significant. Further statistical analyses revealed significant correlations with two extractable principal components allowing interpretation of possible origins of phosphorus loadings. Furthermore, available remediation measures were briefly evaluated for both lakes in consideration of their distinctive environmental features.

为研究重金属对烟叶铜锌超氧化物歧化酶的作用规律,消除活体烟叶中其它因素的影响,本试验采用离体方法,利用硫酸铵盐析分级分离、乙醇-氯仿沉淀除杂、丙酮再沉淀分级得到只含铜锌超氧化物歧化酶的酶液。研究了不同浓度的Fe2+、Mn2+、Se2+、Sb2+、Cd2+对该酶的影响。结果显示:在浓度为0～100mg/L范围内,Fe2+、Mn2+、Sb2+、Cd2+都能使铜锌超氧化物歧化酶的活性先降低后升高,但在相同浓度下,Cd2+对酶活性的影响最大,其次是Mn2+、Fe2+。Sb2+使该酶的活性的变化趋势与Cd2+、Mn2+基本一致,仅变化幅度不及Cd2+、Mn2+显著。Se2+能降低该酶的活性,当浓度为10mg/L时,酶活性的降低率为58.78%。当Se2+浓度为20mg/L时,酶活性几乎完全丧失。分析了铜锌超氧化物歧化酶活性受Fe2+、Mn2+等影响的可能机制,以期为烟草重金属污染的酶学指标监测系统的建立提供数据支持。

The superoxide dismutase in tobacco leaves played a vital role in anti-oxidation.In order to eliminate various environmental factors,the in vitro method was applied in the present investigation to study changing trends of the copper-zinc superoxide dismutase activity caused by rare earth ions.The enzyme solution of copper-zinc superoxide dismutase from tobacco leaves was obtained by using ammonium sulphate to form different levels of precipitates and by using chloroform and alcohol to isolate the impurities and acetone for further clean-up.The effects of La3+,Sm3+,Y3+ and Ce3+ with different concen-trations on copper-zinc superoxide dismutase were studied.The results showed that the activity of copper-zinc superoxide dismutase demonstrated a decreasing trend first,then an increasing trend and finally a decreasing trend in response to the increasing La3+,Sm3+,Y3+ or Ce3+ supply from 0 to 250 mg / L.At the same concentration,however,the change of copper-zinc superoxide dismutase activity under the influence of Y3+ was strongest,and then the Sm3+.The changes in the enzyme activity under the effects of these four rare earth ions were approximately 20%,and the ability of eliminating.O2-varied considerably.

Environmentally significant activity of alkaline phosphatase (APA), phosphorus loading and its species were determined in 14 sediment samples from Lake Hongfeng, one of the key drinking-water sources in Guizhou Province, China. The results of this research indicates that APA presented a high level and notable fluctuations with spatial variations in sediments, ranging from 8.712×10-5 to 25.667×10-5 mol of p-nitrophenol g−1•h-1, and the average value of total phosphorus (TP) in sediments from the lake was 1129.81 mg/kg (dry weight). The content of inorganic phosphorus (IP) was higher than that of organic phosphorus (OP), and the content of the iron/aluminum-bound phosphorus (Fe/Al-P) with phosphorus release risk was also high. In addition, the Pearson’s correlation analysis shows various correlations between APA and Ca-P, Fe/Al-P, OP and IP.

This paper reports an investigation on pollution and potential risk on elements of iron (Fe) and manganese (Mn) in sediments from Lake Aha, which is a drinking-water source for Guiyang City, the capital of Guizhou Province in southwestern China. In the present research, chemical speciation of Fe and Mn in sediments from the lake was studied based on the sequential extraction procedure developed by Tessier et al.. The results obtained from the study are as follows. The average values of total Fe were 47617 mg/kg and 70325 mg/kg in sediments from the lake in summer and winter respectively, and its speciation consisted mainly of residual and Fe-Mn oxides fractions. The amounts of total Fe and the distribution of its speciation in the sediments should be affected by effluents from a large quantity of deserted coal mines in the lake basin in summer and winter. The average values of total Mn were 7996 mg/kg and 1753 mg/kg in summer and winter respectively, and its speciation is primarily comprised of carbonate and Fe-Mn oxides fractions. The amounts of total Mn and its distribution in different fractions in the sediments were believed to be primarily influenced by effluents from those deserted coal mines in summer and by the condition of redox interface in winter.

The distribution characteristies of ammonifier, ammonium-oxidizing bacteria, nitrite-oxidizing bacteria, and denitrifiers, and activities of alkaline phosphatase (ALP) in sediments from Baihua Lake (a man-made deep plateau canyon reservoir in Guizhou Province. China) were Studied. The results suggested that the population number of ammonifiers in the sediments was higher at sampling sites Pingpu, Laojiutu, Yapengzhai, and Jiangjiapu than at the other sites. Ammonium-oxidizing bacteria had the highest population number at sampling site Meituwan. The population number of nitrite-oxidizing bacteria in the upper and middle sections of the lake was higher than that ill the lower section. The population of denitrifiers was the highest at sampling site Jiangjiapu, and all the other sampling sites gave lower population numbers.Change in the activity of ALP was of a strong regularity, and the basic tendency was that the activity increased from the upper to the lower portion of the lake. Specifically, the activity at sampling site Yapengzhai was the strongest. The statistical analysis for four groups of bacteria, ALP, organic matter, and so on were carried Out to shed more light on their correlativity. This research will likely provide relevant data useful for establishment of bacteriological and zymological indicator systems for environmental monitoring. (c) 2009 Curtin University of Technology and John Wiley & Sons, Ltd.

Baihua Lake, a man-made reservoir, is one of the five drinking water sources for Guiyang City in China's southwestern province of Guizhou. In the present research, the distribution and accumulation characteristics of heavy metals (Pb, Cd, As, Cu and Zn) for the sediment of this lake were analyzed by examination of 10 recently collected samples. A method based on toxic-response factor was applied to assess the potential ecological risk of these heavy metals to the water body. For comparison, the two sets of reference data representing the pre-industrial and the local baseline pollution levels were employed to derive the accumulating coefficients for the heavy metals under study. The calculated potential ecological risk indices show that the lake was polluted by heavy metals and both cadmium and arsenic loadings were critical factors responsible for the ecological hazards posed to Baihua Lake by the five elements.

Baihua Lake and Aha Lake are both drinking-water sources for Guiyang City, the capital of Guizhou Province in southwestern China. In the present research, chemical speciation of chromium (Cr), copper (Cu) and zinc (Zn) in the sediments from these two lakes was studied based on the sequential extraction procedure developed by Tessier et al., and organic matter (OM) was determined by ignition method. The results obtained are as follows:111 The organic matter amounts in sediments from Baihua Lake and Aha Lake ranged from 11.62 to 18.02% and 8.48 to 13.90%, respectively; Cr-[2] and Zn were mainly distributed in residual phase, while Cu mainly existed in oxidizable and residual phases;([3]) Levels of Cu distributed in oxidizable phase in sediments from Baihua Lake were higher than those from Aha Lake;([4]) Mobility, bioavailability, and toxicity of Cu were low in comparison with Zn and Cr, because Cu was mainly distributed in oxidizable and residual phases in which heavy metals mobility was lower than in the other phases. The Pearson's correlation coefficient between organic matter and Cr in oxidizable phase of the 20 sediment samples collected from the two lakes was Lip to 0.604 (p < 0.01). (C) 2009 Curtin University of Technology and John Wiley & Sons, Ltd.