玻璃海鞘脂肪酸提取工艺的研究

用乙酸乙酯从玻璃海鞘中提取多不饱和脂肪酸,通过正交实验对提取工艺进行研究,得其最佳提取条件为：温度50℃,提取时间240min,料液比1：3,提取次数2次。按此工艺提取,得脂肪酸产率为1．22％,利用气相色谱进行分析,得其中多不饱和脂肪酸含量为66．40％,EPA和DHA含量之和为15．20％。     

基于移动测量的交通标志自动提取

针对从移动测量车采集的图像中提取交通标志的需求,研究探索适合移动测量的交通标志检测识别方案。在交通标志检测阶段,提出一种检测多个圆形禁令标志连接的多圆度检测法,对于三角形警告标志的检测,在原有拐角检测法基础上提出基于候选区域的拐角检测法;在交通标志识别阶段,选用像素特征作为特征向量,采用概率神经网络实现交通标志的分类识别。最后设计实现移动测量后处理软件的交通标志自动提取模块。     

Metal Ion Extraction with Bipyridine Derivatives as Chelating Ligands in Supercritical Carbon Dioxide

Three fluorinated bipyridine ligands have been designed and synthesized as chelating agents for the extraction of metal ions in supercritical CO₂ (sc‐CO₂). The ligand solubilities in sc‐CO₂ were investigated at different temperatures and pressures, and the measured data have been correlated using a semiempirical model. The calculated results showed satisfactory agreement with the experimental data. Based on these data, metal ion extraction with the three compounds as chelating agents in sc‐CO₂ was performed from spiked filter paper, whereby ligand 1 showed the highest extraction efficiency, especially for Ni²⁺ and Cu²⁺. The extraction constants, K_ex, of the three chelating ligands were seen to increase with increasing extraction efficiency for the same metal ion in the same extraction system.     

利用GVG线采样技术提取农作物种植面积及其精度分析

GVG(GIS&Video&GPS)线采样系统提出以线状样区代替以往成数抽样中的点样区与面积样区概念,通过统计线状样区内作物种植面积成数来反映区域总体农作物种植面积成数。通过 GVG实地采样,将其结果与解译遥感影像提取的作物种植面积成数结果进行了对比分析,结果显示采用GVG线采样方式精确度较高,其采样系统具有实用性和推广价值。     

Bulk-rock Major and Trace Element Compositions of Abyssal Peridotites: Implications for Mantle Melting, Melt Extraction and Post-melting Processes Beneath Mid-Ocean Ridges

This paper presents the first comprehensive major and traceelement data for 130 abyssal peridotite samples from the Pacificand Indian ocean ridge–transform systems. The data revealimportant features about the petrogenesis of these rocks, mantlemelting and melt extraction processes beneath ocean ridges,and elemental behaviours. Although abyssal peridotites are serpentinized,and have also experienced seafloor weathering, magmatic signaturesremain well preserved in the bulk-rock compositions. The betterinverse correlation of MgO with progressively heavier rare earthelements (REE) reflects varying amounts of melt depletion. Thismelt depletion may result from recent sub-ridge mantle melting,but could also be inherited from previous melt extraction eventsfrom the fertile mantle source. Light REE (LREE) in bulk-rocksamples are more enriched, not more depleted, than in the constituentclinopyroxenes (cpx) of the same sample suites. If the cpx LREErecord sub-ridge mantle melting processes, then the bulk-rockLREE must reflect post-melting refertilization. The significantcorrelations of LREE (e.g. La, Ce, Pr, Nd) with immobile highfield strength elements (HFSE, e.g. Nb and Zr) suggest thatenrichments of both LREE and HFSE resulted from a common magmaticprocess. The refertilization takes place in the ‘cold’thermal boundary layer (TBL) beneath ridges through which theascending melts migrate and interact with the advanced residues.The refertilization apparently did not affect the cpx relicsanalyzed for trace elements. This observation suggests grain-boundaryporous melt migration in the TBL. The ascending melts may notbe thermally ‘reactive’, and thus may have affectedonly cpx rims, which, together with precipitated olivine, entrappedmelt, and the rest of the rock, were subsequently serpentinized.Very large variations in bulk-rock Zr/Hf and Nb/Ta ratios areobserved, which are unexpected. The correlation between thetwo ratios is consistent with observations on basalts that D_Zr/D_Hf< 1 and D_Nb/D_Ta < 1. Given the identical charges (5⁺ forNb and Ta; 4⁺ for Zr and Hf) and essentially the same ionicradii (R_Nb/R_Ta = 1·000 and R_Zr/R_Hf = 1·006–1·026),yet a factor of 2 mass differences (M_Zr/M_Hf = 0·511 andM_Nb/M_Ta = 0·513), it is hypothesized that mass-dependentD values, or diffusion or mass-transfer rates may be importantin causing elemental fractionations during porous melt migrationin the TBL. It is also possible that some ‘exotic’phases with highly fractionated Zr/Hf and Nb/Ta ratios may existin these rocks, thus having ‘nugget’ effects onthe bulk-rock analyses. All these hypotheses need testing byconstraining the storage and distribution of all the incompatibletrace elements in mantle peridotite. As serpentine containsup to 13 wt % H₂O, and is stable up to 7 GPa before it is transformedto dense hydrous magnesium silicate phases that are stable atpressures of 5–50 GPa, it is possible that the serpentinizedperidotites may survive, at least partly, subduction-zone dehydration,and transport large amounts of H₂O (also Ba, Rb, Cs, K, U, Sr,Pb, etc. with elevated U/Pb ratios) into the deep mantle. Thelatter may contribute to the HIMU component in the source regionsof some oceanic basalts. KEY WORDS: abyssal peridotites; serpentinization; seafloor weathering; bulk-rock major and trace element compositions; mantle melting; melt extraction; melt–residue interaction; porous flows; Nb/Ta and Zr/Hf fractionations; HIMU mantle sources     

面向对象的湿地景观遥感分类——以杭州湾南岸地区为例

在ENVIEX软件的Feature Extraction平台上,利用LandsatTM影像数据,采用面向对象方法对杭州湾南岸地区湿地景观进行遥感影像分类;通过与基于最大似然法、人工神经网络法、支持向量机法等传统像元方法的相应分类结果进行比较,系统分析了面向对象方法在中低分辨率遥感影像的湿地景观生态分类中的有效性。研究结果表明:①较之单一依据像元光谱值进行分类的传统方法,面向对象方法综合考虑了对象的光谱、空间、纹理、色彩等多种属性特征,因而对于类型复杂多样、分布界限模糊、光谱混淆与混合像元现象严重的沿海滩涂、湖泊、河流等湿地景观具有更好的鉴别能力,也因此获得更高的分类精度(研究区景观分类总精度为88.80%,Kappa系数为0.8765);②面向对象方法在分类中提取的是由同质性像元组成的"对象",且在合理的影像分割下得到的对象破碎化程度较低,因而能在较大程度上减小分类结果中的"椒盐噪声"干扰;而基于像元方法提取的景观类型以离散像元形式组成,难以清晰表征景观的边界、形状等信息,所以分类结果中会有明显的噪声现象;③影像分割在运用面向对象方法进行遥感影像分类过程中具有重要影响,实验结果表明,60%的分割尺度和归并尺度组合较有利于中低分辨率影像的遥感分类;④面向对象分类过程中诸如影像分割精度的评价、最优分割尺度的选取、特征空间的优化等问题,则有待今后进一步探讨。     

基于相干特征的岩石薄片序列图像边缘提取及颗粒分割

针对岩石颗粒边缘模糊、结构复杂的特点,为了更有效地识别颗粒边缘,在基于特征值的C3相干算法的基础上,融合多尺度和多角度的特征表达,提出了一种改进的C3相干算法。该算法综合考虑岩石薄片图像角度域光学特征、空间尺度信息和各向异性信息,能更有效地表征颗粒边缘特征,表现出对复杂矿物结构的适应能力。在采集的岩石薄片正交偏光图像上验证提出的算法,实验结果表明,与原生C3相干算法相比,改进后的C3相干算法在全局图像上的方差和灰度差分乘积分别提升了68.41%和22.91%,信息熵下降了21.61%。     

Triggered earthquakes and deep well activities

Earthquakes can be triggered by any significant perturbation of the hydrologic regime. In areas where potentially active faults are already close to failure, the increased pore pressure resulting from fluid injection, or, alternatively, the massive extraction of fluid or gas, can induce sufficient stress and/or strain changes that, with time, can lead to sudden catastrophic failure in a major earthquake. Injection-induced earthquakes typically result from the reduction in frictional strength along preexisting, nearby faults caused by the increased formation fluid pressure. Earthquakes associated with production appear to respond to more complex mechanisms of subsidence, crustal unloading, and poroelastic changes in response to applied strains induced by the massive withdrawal of subsurface material. As each of these different types of triggered events can occur up to several years after well activities have begun (or even several years after all well activities have stopped), this suggests that the actual triggering process may be a very complex combination of effects, particularly if both fluid extraction and injection have taken place locally. To date, more than thirty cases of earthquakes triggered by well activities can be documented throughout the United States and Canada. Based on these case histories, it is evident that, owing to preexisting stress conditions in the upper crust, certain areas tend to have higher probabilities of exhibiting such induced seismicity.     

Iron and phosphorus effects on the growth of Cryptomonas sp. (Cryptophyceae) and their availability in sediments from the Pearl River Estuary, China

Based on lab-culture experiments analyzing limitation and combination of iron and phosphorus on the growth of Cryptomonas sp. (Cryptophyceae), and the study of accumulation and release of Fe-bound P in sediment cores collected from the marine region of the Pearl River Estuary, China, reasons for the high frequency of phytoplankton bloom therein are discussed. Results show that the combined effect of Fe and P can obviously accelerate algal development, and the optimum culture conditions maintaining maximum growth rate are 0.05 μM Fe and 50 μM P. Cellular contents of Fe and P is consistent and the P:Fe molar ratio is 159:1. The optimum range of the P:Fe molar ratio in culture experiments for cell incubation is 500–1400. The vertical trends of total Fe and total P variations in sediments are parallel. Fe-bound P is the main species of inorganic sedimentary P. Through continuous leaching with agitation, 34–80% of exchangeable P and 4–23% of exchangeable Fe are concurrently released from the surficial sediments. This is a possible way by which nutrients are made available to phytoplankton. These factors might be responsible for a high frequency of harmful algal blooms in the Pearl River Estuary.     

基于地物特征提取的车载激光点云数据分类方法

车载激光扫描测量方法较传统摄影测量方法具有更多优点,它能快速采集大面积、高精度的三维空间数据,具有广阔的应用前景。针对车载激光扫描数据的分类问题,提出了一种基于地物特征提取的点云数据分类方法,即采用主成分分析(PCA)方法,在提取多种街区地物点云数据几何特征和总结地物对象特征知识规则的基础上,根据选取的主特征设计一套阶层式的分类方法,并利用该方法对一套车载激光点云数据进行了分类试验。结果表明,该方法的分类效果良好,具有一定的实用性。