Extraction,isolation and structural characterization of polysaccharides from a red alga <Emphasis Type="Italic">Gloiopeltis furcata</Emphasis>

Three kinds of polysaccharides:GFW,GFH and GFA,were sequentially extracted from a red alga Gloiopeltis furcatawith 25℃and 85℃water,and 60℃ 4%NaOHwater solution.Based on the defatted alga,the yields of the polysaccharide were57.9%,2.5%and 2.6%,respectively.Their monosaccharide compositions,average molecular weights and structural characters weredetermined by gas chromatography(GC),high performance liquid chromatography(HPLC),fourier transform infrared spectroscopy(FTIR)or13C-NMR spectroscopy.The results show...     

Effects of pyrene and fluoranthene on the degradation characteristics of phenanthrene in the cometabolism process by Sphingomonas sp. strain PheB4 isolated from mangrove sediments

Cometabolism has been suggested as an attractive approach to enhance the degradation rates of high-molecular-weight polycyclic aromatic hydrocarbons (PAHs). However, the effects of these recalcitrant PAHs on the degradation characteristics of low-molecular-weight PAHs are largely unknown. This study was conducted to investigate the effects of pyrene (PYR) and fluoranthene (FLA) on the degradation characteristics of phenanthrene (PHE) in the cometabolism process by Sphingomonas sp. strain PheB4 isolated from mangrove sediments. Based on the kinetics and characteristics of PHE metabolites, it was proposed that the transformation of hydroxylated PHE into 1-hydroxy-2-naphthoic acid was a rate-limiting step in the degradation of PHE by strain PheB4. Compared to a single addition of PYR or FLA, the presence of a mixture of PYR and FLA decreased the degradation rate of PHE to a larger extent, which was likely because it could inhibit the production of 1-hydroxy-2-naphthoic acid more effectively.     

黄土覆盖区钼矿综合地球物理找矿技术组合:以沙坡岭钼矿为例

覆盖区寻找隐伏矿成为当前找矿工作的热点问题,为了能在地表地质信息少的黄土覆盖区,寻找隐伏的有经济价值的矿床,本文以沙坡岭钼矿为例,综合应用r能谱、高精度磁法、高密度电法三种地球物理方法进行找矿勘探,辅以偏提取化探法对地球物理异常进行约束,结合地质资料进行解译,预测了有利的成矿区域,通过钻探得到了有效验证,初步建立了黄土覆盖区钼矿的综合地球物理找矿模式,为下一步的综合勘探打下了基础.     

分层抽取法在泥沙沉积过程中的应用研究

悬浮泥沙到沉积土的形成过程非常复杂,涉及到泥沙的沉降和土的自重固结。物理模型试验需要实测含水率、密度、颗粒分布、超孔隙水应力和总应力,但目前尚无简单可行的方法。提出了一种改进的室内试验方法,通过与国内外现有试验方法相对比,改进后的方法不仅可以得到泥沙在沉积过程中的泥面下沉变化、含水率（密度）分布、超孔压消散剖面,而且还能得到沉积物在不同高度和时间的颗粒分布变化等性质。通过多个试验实测及一致性测试表明,实测数据合理、可信,一致性检验误差较小,验证了此方法的可行性。     

基于累积法理论的弹性阻抗参数提取

弹性阻抗中蕴含着丰富的地下介质信息。从弹性阻抗中准确地提取地下介质信息用于储层预测是十分有意义的,传统的提取方法主要基于最小二乘理论的线性方法。本文引入累积法理论,将其用于弹性阻抗参数的提取,用层状模型和部分Marmousi2模型对该方法进行测试。从背景噪声分别为正态分布和均匀分布的弹性阻抗体中提取纵、横波速度和密度,并将其与最小二乘法提取的纵、横波速度和密度做定量对比分析。结果表明两种方法所得结果精度相当,但累积法具有计算量小、简洁直观的优势,因此,将其用于弹性参数的提取是有效可行的。      

基于Landsat-8与ZY3多源遥感影像的城镇居民地识别与再分类研究

精细的居民地数据对地震灾害风险分析具有重要意义。 为得到具有较高时效性与精细度的居民地数据, 充分发挥其对人口、 建筑物空间展布的指示作用, 本文综合利用多源遥感影像的优势, 基于分层分类思想开展城镇居民地识别与再分类研究。 以甘肃天水秦州区的主城区为例, 采用具有较高时效性的Landsat-8 OLI影像, 建立决策树分类模型识别出居民地轮廓; 在居民地轮廓内部, 进一步采用资源三号卫星(ZY3)高分影像, 利用面向对象方法进行居民地内部的建筑群再分类, 最后得到了具有不同精细程度的居民地数据。 实验结果中Landsat-8土地覆盖分类总体精度为92%(其中居民地识别率达86%), 城镇居民地再分类的总体精度为81%, 说明了本文研究方案的可行性。     

基于四阶累积量的同相轴自动拾取方法

针对强随机噪声干扰情况下地震勘探资料中同相轴无法正确拾取的问题,提出了基于四阶累积量的同相轴自动拾取方法。该方法利用四阶累积量进行时间延迟估计,避免了相关高斯噪声的影响;同时在参考道的选择上,以一定的间隔设置多个参考道,减少了同相轴拾取过程中的累积误差。理论模型计算表明:该方法相对于互相关方法,对相关高斯噪声有更强的抑制能力,信噪比达到-5 dB。在实际资料应用中,拾取了与同相轴有关的参数：同相轴位置,该参数为地震资料的属性分析和精确定量解释提供了依据。     

Trace Elements in Sediments and Mussels – Spatial Distribution,Chemical Partitioning,and Risk Assessment

Sediment samples were collected from 30 different locations in Abu Qir Bay (Mediterranean Sea), East Alexandria, Egypt and analyzed for trace elements. The highest concentrations of most of the elements were observed in the nearshore stations in the vicinity of the major anthropogenic activities as industrial settlements, wastewater discharges, and agricultural drainage. In addition, mussel samples of Mactra corallina and Tapes decussata were collected corresponding to the sediment samples. Concentrations of As, Cd, Cr, Mn, and Zn in the mussel tissues were higher than concentrations in sediments, thus indicating their relatively high bioavailability. Sequential extraction procedure was performed on selected sediment samples. Significant correlations were observed between the concentrations of Cu, Mn, Pb, and Zn in the exchangeable fraction of the sediments and the corresponding tissues of M. corallina. The output of the risk assessment applied on the sediments revealed that adverse ecological effects to benthic species could occur and that a higher level of risk is expected from the exposure to Cd, Cr, Hg, and Zn. No adverse carcinogenic or non‐carcinogenic human health effects are expected from the consumption of the two mussel species from Abu Qir Bay.     

Detection of Pharmaceuticals and Personal Care Products in Agricultural Soils Receiving Biosolids Application

Increasing research has suggested that biosolids generated from municipal wastewater treatment can be a major sink for many pharmaceuticals and personal care products (PPCPs) and their land application potentially introduces these contaminants into the terrestrial and aquatic environments. In this study, methods were developed for the analysis of 14 PPCPs in biosolids and soils using pressurized liquid extraction, solid phase extraction and liquid chromatography‐tandem mass spectrometry. Recoveries were over 50% for all analytes except diphenhydramine (?30%) in soils. Soil properties or type of biosolids showed minor effects on method recoveries. Estimated method limits of quantification (LOQ) range from 0.1–15 ng g^–1 for soil and 0.3–27 ng g^–1 for biosolids. A field study utilizing the methods revealed that other than carbamazepine‐10,11‐epoxide, all targeted compounds were detected in biosolids. Diphenhydramine, fluoxetine, triclosan and triclocarban were detected up to the μg g^–1 range with the highest concentration of 23 μg g^–1 for triclocarban. Seven of the PCCPs found in biosolids were also detected in agricultural soils amended with these biosolids and several (carbamazepine, diphenhydramine, and triclocarban) appeared to be persistent in soils. Triclocarban was also found most abundant in soils with the highest average concentration of 0.2 μg g^–1 while the rest of compounds were in the lower ng g^–1 range. Generally, the concentrations found on the fields were 2–3 degrees of magnitude lower than in the biosolids, which is likely to be due to dilution, degradation and leaching processes.