Discrete wavelet‐based trend identification in hydrologic time series

Trend identification is a substantial issue in hydrologic series analysis, but it is also a difficult task in practice due to the confusing concept of trend and disadvantages of methods. In this article, an improved definition of trend was given as follows: ‘a trend is the deterministic component in the analysed data and corresponds to the biggest temporal scale on the condition of giving the concerned temporal scale’. It emphasizes the intrinsic and deterministic properties of trend, can clearly distinguish trend from periodicities and points out the prerequisite of the concerned temporal scale only by giving which the trend has its specific meaning. Correspondingly, the discrete wavelet‐based method for trend identification was improved. Differing from those methods used presently, the improved method is to identify trend by comparing the energy difference between hydrologic data and noise, and it can simultaneously separate periodicities and noise. Furthermore, the improved method can quantitatively estimate the statistical significance of the identified trend by using proper confidence interval. Analyses of both synthetic and observed series indicated the identical power of the improved method as the Mann–Kendall test in assessing the statistical significance of the trend in hydrologic data, and by using the former, the identified trend can adaptively reflect the nonlinear and nonstationary variability of hydrologic data. Besides, the results also showed the influences of three key factors (wavelet choice, decomposition level choice and noise content) on discrete wavelet‐based trend identification; hence, they should be carefully considered in practice. Copyright © 2012 John Wiley & Sons, Ltd.     

黄山东镁铁超镁铁杂岩中的辉石化学成分研究

通过对黄山东镁铁超镁铁杂岩的辉石化学成分研究，证明辉石的化学成分受寄主岩石类型的制约，从超镁铁岩相到角闪辉长岩相斜方辉石的化学成分由富ＭｇＯ、ＳｉＯ＿２、Ａｌ＿２Ｏ＿３、Ｃｒ＿２Ｏ＿３到富ＦｅＯ、ＴｉＯ＿２、ＣａＯ、ＭｎＯ；单斜辉石化学成分由富Ａｌ＿２Ｏ＿３、Ｃｒ＿２Ｏ＿３、Ｎａ＿２Ｏ、ＭｇＯ到富ＦｅＯ、ＭｎＯ、ＣｏＯ。在同一寄主岩石中，单斜辉石比斜方辉石富ＴｉＯ＿２、Ａｌ＿２Ｏ＿３、Ｃｒ＿２Ｏ＿３、ＣａＯ和Ｎａ＿２Ｏ，贫ＭｇＯ、ＳｉＯ＿２、ＭｎＯ和ＦｅＯ。根据辉石化学成分特征得出黄山东杂岩形成于岛弧环境，为上地幔石榴二辉檄榄岩部分熔融形成的拉斑玄武岩岩浆结晶分异作用的产物。     

湖南大坊金银矿氧化带特征及工业意义

湖南大坊金银矿位于耒阳—临武南北向构造带中段,控矿层位为石炭系中上统壶天群和下统梓门桥组白云岩。矿体受北西和北东向组扭裂面的控制,产于花岗闪长斑岩内外接触带。氧化带的有用组分为金和银,已圈定矿体7个,其平均品位Au 2.68 g/t,Ag26.20g/t。金的粒度以中—细粒为主,氰化浸出率在91％以上,银经槽浸回收率仅20-30%。鉴于金浸出率高,矿体埋藏浅。开采技术条件简单,交通方便等特点,值得开发利用。     

Geomorphology and sedimentary/biosedimentary structures of the intertidal environment along the coast of Kuwait,north-western Arabian Gulf

The coast of Kuwait can be divided into nine intertidal geomorphological subunits, of which four are found along the northern muddy shoreline and five along the southern sandy shoreline. In the north the coast is characterized by wide intertidal mudflats, bounded landward by an extensive coastal sabkha which is partly covered by sand drifts. The upper part of the intertidal environment is covered with a mixture of aeolian sands and muddy sediments of marine origin. A number of shallow tidal channels dissect the intertidal flats and small sand bars occur near the low water line. In contrast, the southern shore is characterized by relatively steep sandy beaches fronted by narrow to moderately wide rocky intertidal platforms which are partly covered by sand, bioherms, skeletal debris and algal mats. In some areas the rocky surface is dissected by numerous small gulleys and shallow channels. Multiple sand bars lying either parallel or diagonal to the shoreline are developed near the low water line. This southern intertidal environment is bounded landward by a sandy berm and a wave-cut cliff.Ripple marks are developed almost parallel to the shoreline, showing different flow directions. Energy levels are moderate to high along the southern shore, but low along the northern shore. In the south, waves induced by winds blowing mostly from the north-east and south-east form the dominant energy source, whereas tidal and wind-driven currents are the only tangible process acting along the northern shore.     

高表面活性矿物对Zn~(2+)的吸附机理及其环境意义

本文利用高表面活性矿物蒙脱石、蛭石、沸石在一定的介质条件下对Zn2 +进行吸附实验研究。蒙脱石和蛭石对Zn2 +的等温吸附线呈双“S”型 ,而沸石对Zn2 +的等温吸附线则呈“Langmuir”型。三种矿物对Zn2 +的吸附容量大小顺序为 :蒙脱石 >蛭石 >沸石。运用粉晶X射线衍射、红外光谱、差热及热重分析等技术对矿物及矿物吸附Zn2 +后的结构特征进行了研究。结果表明 ,蒙脱石吸附锌后其层间域中吸附锌大量水解形成新的物相 ,而蛭石与沸石吸附锌后水解很少。这为利用高表面活性矿物控制和治理环境污染及其可循环利用提供了理论依据。     

千岛岛弧大震前哈佛大学矩心矩张量（CMT）解一致性的预测意义s

千岛岛弧地区属于全球地震活动最为活跃的地区之一. 本文利用哈佛大学测定的千岛岛弧地区地震的矩心矩张量（CMT）解， 分析该地区震源机制的一致性特征， 提出利用震源机制和构造应力场的一致性参数a进行地震预测的思路. 研究结果表明，MＷge;7.5地震之前， 都有一致性参数a降低的现象，a的低值起始的时间在发生大震之前的10多天至110多天， a的低值截止的日期距大震在30多天至2天. 相互之间虽然并不完全一致， 但是差别不大. 这种现象的稳定性， 尚需时间的检验， 但是设想在长达数百公里的地区， 连续发生MＷge;5.3的地震的震源机制都与构造应力场一致， 应当不是随机的现象， 而是一种具有预测意义的现象. 当积累的震例足够多时， 则有可能确定统一的评判标准和预测准则.      

发达国家资源安全供应模式及其借鉴意义

资源安全供应是保障国民经济持续健康发展的必要条件。阐述了发达国家资源安全供应的3个模式：比较优势模式、贸易一投资模式和系统论模式。通过实例，就模式的作用机理进行了简要分析。结合我国的实际情况，借鉴发达国家资源安全供应的经验，就我国资源的安全供应提出了4个方面的建议。     

柴东侏罗系源岩生油组分荧光特征与生烃意义

通过荧光特征研究了柴达木盆地东部侏罗系源岩生油组分,指出了不同生油组分对生烃的贡献、意义及其热演化特征。侏罗系源岩有暗色泥岩、油页岩、煤和炭质泥岩四种类型,主要生油组分为壳质组和矿物—沥青基质,不同生油组分荧光特征的差异又是生烃潜力大小、热演化程度和降解情况的综合反映。     

Gyrolithes:边缘海沉积的特征遗迹化石

Gyrolithes为螺旋形垂直居住潜穴,是具成对附肢的两侧对称甲壳类所建造,出现在近海泻湖和河口湾等边缘海和极浅海环境中,常与半咸水条件有关。塔里木盆地塔中地区诸多钻井的下志留统塔塔埃尔塔格组上部大量发育有此类潜穴,在局部层位可形成强烈的扰动构造。伴生的遗迹化石很少,只有极个别的Beaconites。根据沉积学、地球化学和古生态学特征,这类潜穴形成在半咸水的泻湖环境中。这类潜穴外壁基本平直,在泥质沉积物中掘穴深度大而不变形,而且其充填物与围岩完全不同,这些特点表明Gyrolithes为固底控制的遗迹化石。     

陕西安康砂金矿物特征及地质找矿意义

通过对陕西安康地区大量砂金矿物的形态、显微结构及化学成分特征的研究,发现全区砂金按成色可明显划分为北、中、南三个分区,并与地质背景相印证;在形态特征上以其特有的镶嵌结构、蜂窝状结构及晶洞状结构等标型特征与原生自然金相区别。并总结出砂金矿物的不同形态、成色特征和空间变化及所反映的地质找矿意义。