消除EMD 边界效应的四中点估计方法

为了快速高效地实现信号的本征模态分解,消除分解过程中边界效应,在 Directly-Mean EMD方法的基础上,通过引入左、右待估中点和左、右延拓中点,并根据信号首尾两端各种可能的情况给出了四中点估计公式,建立了可完全消除边界效应的Directly-Mean EMD四中点估计方法。该方法不仅减少了样条插值次数,提高分解速度,而且还可以有效避免因插值节点过于稀疏所产生的大幅波动,使分解结果更加准确。将新方法应用于日长数据序列的本征模态函数分解,得到了满意的分解结果。     

First documented southern transatlantic migration of a blue shark Prionace glauca tagged off South Africa

The first documented recapture of a South African-tagged juvenile blue shark Prionace glauca off Uruguay lends weight to the hypothesis of a single blue shark population in the South Atlantic. The presence of neonate blue sharks with umbilical scars and females with post-parturition scars, as well as the high frequency of small juveniles in research longline catches, confirm the existence of a parturition and nursery area off South Africa. The final positions of three tagged sharks suggest that large-scale movement patterns in the South Atlantic are a mirror image of movements in the North Atlantic, with sharks using the north-westerly Benguela Drift to migrate into the tropics and ultimately across into South American waters. The confirmed existence of a parturition and nursery area off the south coast of South Africa and the movement of sharks into both adjacent ocean basins suggest that the southern African blue sharks are part of a single stock that straddles the South Atlantic and Indian oceans, and possibly the entire Southern Hemisphere.     

A Siltation Simulation and Desiltation Measurement Study Downstream of the Suzhou Creek Sluice, China

The Suzhou Creek Sluice is currently the largest underwater plain gate in the world, with a single span of 100 m. It is located in a tidal estuary at the junction of the Huangpu River and Suzhou Creek in Shanghai, China. In this study, physical and 2D vertical mathematical models were used to investigate and distinguish the mechanism of siltation downstream of an underwater plain gate from that of other gates types. According to quantitative data obtained by site investigation and the application of the physical hydrodynamic models, it was found that the characteristics of the tidal estuary as well as the fact that the sluice span is equal to the creek width are the major reasons contributing to siltation. A possible desiltation treatment system is proposed for the underwater plain gate. The system includes selection of a suitable location that allows the determination of a reasonable top elevation of the sluice floor, reserving sufficient space under the gate to accommodate siltation, setting up a mechanical desiltation system, and flushing silt along with overflow over the top of the gate. Furthermore, on-site hydraulic silt flushing experiments and a topography survey were conducted. These results showed that the measurement system is effective, and by maintaining this scheduled operation once a month, the downstream riverbed has been maintained in a good condition.     

Development of a sound reflection system for profiling sediments in shelf and slope depths

A sound reflection system for obtaining profiles of sedimentary structures in shelf and slope depths to 500 m has been developed, based on an Edgerton 1 kJ boomer as sound source. A logarithmic response receiver allows optimal recording of signals over a wide dynamic range. Penetrations of up to 500 m have been obtained from structures within both unconsolidated sediments and folded lower Tertiary structures. The equipment works reliably at speeds up to 9 knots.     

Mapping QTLs of caudal fin length in common carp (Cyprinus carpio L.)

Common carp (Cyprinus carpio L.) exhibits significant morphological variability in the shape and size of the caudal fin. In this study, we used 190 progeny from two F₁ parents to identify and map quantitative trait loci (QTLs) that influence caudal fin length (CFL) and the ratio (RCS) between caudal fin length and standard length (SL) based on a microsatellite genetic map of common carp. A total of 15 QTLs were detected in seven different linkage groups. One significant and eight suggestive QTLs affecting CFL were identified on LG8, LG14, LG29, LG32 and LG44, which explained 8.0%–22.1% of the phenotypic variation; six suggestive QTLs affecting RCS were detected on LG8, LG32, LG46 and LG48, which explained 7.0%–15.4% of the phenotypic variation. The QTLs for caudal fin length detected in this study may serve as a starting point for identification of genes involved in caudal fin development in common carp.     

Lethal concentrations of suspended solids for common native fish species that are rare in New Zealand rivers with high suspended solids loads

Abstract

Common native fish species that are rare in New Zealand rivers with high suspended solids (SS) concentrations were identified to determine which species were likely to be most affected by high SS concentrations. Mortality rates for the three most sensitive species (banded kokopu Galaxias fasciatus, redfin bully Gobiomorphus huttoni, common smelt Retropinna retropinnd) were measured over a range of SS concentrations to identify lethal concentrations. The survival of banded kokopu and redfin bully was not reduced by SS concentrations up to 43 000 g m^?3; however, the 24‐h survival of common smelt was reduced by SS concentrations over 1000 g m^?3, and its median lethal concentration (LC50) was close to 3000 g m^?3. SS concentrations over 3000 g m^?3 for more than 24 h will therefore reduce smelt but not affect the mortality of most other common native fish species. Although mortality from high concentrations of SS can account for the scarcity of smelt in rivers with high SS concentrations, mortality from high SS does not explain the scarcity of banded kokopu or redfin bully in such rivers. High turbidity (>20 nephelometric turbidity units) is known to limit the upstream migration and recruitment of juvenile banded kokopu in rivers with increased SS concentrations. Banded kokopu is therefore affected by increased turbidity from SS rather than lethal SS concentrations. As redfin bully were not affected by either high turbidity levels or high SS concentrations, the low abundance of this species in rivers with high SS concentrations is likely to be related to the siltation of benthic habitats.     

气井水力压裂有效缝长评估及影响因素研究

为了准确确定气井压后有效缝长及其影响因素,提高川西须家河气藏水力压裂针对性,对于具备生产历史拟合条件的气井,利用数值模拟软件进行了生产历史拟合获得有效水力裂缝缝长,与采用净压力拟合方法获得的水力裂缝支撑缝长进行对比和拟合,获得了有效缝长和支撑缝长的关系式,计算了川西须家河储层单井压后有效缝长;采用灰色关联分析理论分析了各个参数对有效缝长的影响程度和对压裂设计的启示。结果表明：压后有效缝长与支撑缝长具有较强相关性(Le=00584 Lp1359 3),有效缝长明显比支撑缝长短;施工参数(特别是用液量)是影响须家河储层有效缝长的关键,而储层和隔层间应力差则是影响有效缝长的重要客观因素。该研究方法为水力压裂压后评估和提高压裂设计水平提供了较好的借鉴。     

农田表面粗糙度参数的测量与精度分析

表面粗糙度是有效解释雷达后向散射系数和微波辐射亮度温度的关键参数之一。表面粗糙度参数的测量精度受到测量方法、测量仪器、数据预处理等的影响,如何获取到表面粗糙度的"真"值是地表粗糙度测量急需解决的问题,并且有助于提高利用微波遥感技术反演地表参数的能力。本文利用激光扫描仪的二维高度数据和蒙特卡罗方法模拟的一维表面高度数据,分析了重复采样次数、采样间隔、采样剖面长度、空间自相关函数类型和大尺度结构(数据倾斜和农田垄行结构)对表面粗糙度精度的影响,研究表明:在大于20次重复采样、小于10mm的采样间隔、200倍相关长度的剖面长度的条件下,农田表面粗糙度参数的测量精度约为80%;分形相关函数与实测农田表面的空间自相关系数的吻合性要高于高斯函数和指数函数;数据倾斜和农田垄行结构严重影响表面粗糙度参数的结果,在进行表面粗糙度参数的计算之前,需从剖面高度分布数据中去除以上两个因素的影响。     

出现于南沙海域的黄带棘箱鲀的形态特征

2011年4月17日在南沙海域调查时,采集到2尾棘箱鲀属(Kentrocapros)标本,经鉴定为黄带棘箱鲀(Kentrocapros flavofasciantus),标本现保存在南海水产研究所标本馆.标本体长分别为108、135 mm.无鳍棘和腹鳍,背鳍和臀鳍各1个.背鳍鳍条数目为11,胸鳍鳍条数目为12,臀鳍鳍条数目为10,尾鳍鳍条数目为11.体长为体高的2.41～2.57倍,体宽的3.07～3.09倍,头长的3.38～3.48倍,吻长的4.35～4.70倍.头长为眼径的2.22～2.38倍,眼间隔的1.35～1.54倍,鳃孔长度的3.10～3.33倍.除尾柄、胸鳍基部、背鳍基部、臀鳍基部、肛门附近之外,体披硬体甲,体甲刚好在背鳍前方闭合,体甲为6棱形,无刺平滑,从肛门连续沿纵线到胸鳍基部下前方形成裸褶.体侧无侧线.上下颌每侧具8个小柱状切牙.胸鳍最上第一鳍条很短,长度约为第二鳍条的1/6.体为褐黄色,体甲有两条较宽的纵向黄带.唇为褐棕色,牙为红褐色.所有鳍条为黄色或略显褐黄色.     

淤泥质、粉沙质及沙质海岸航道回淤统一计算方法

根据20世纪80年代初提出的淤泥质海岸航道回淤计算方法的基础上,开展了拓展研究,使之统一适用于淤泥质海岸、粉沙质海岸及沙质海岸。主要研究内容有,在波浪和潮流综合作用下挟沙力含沙量研究中引入了特定的泥沙因子F1/F,从而挟沙力含沙量公式不仅适用于淤泥质泥沙,也适用于非淤泥质泥沙;在动力因素方面,除了一般寻常潮和波浪动力外,进一步考虑了风暴潮和破波的巨大掀沙能力造成航道骤淤的可能性。并结合连云港30万吨级主航道扩建及徐圩港区10万吨级航道的回淤问题(包括骤淤可能性问题),京唐港外航道和黄骅港外航道的骤淤问题,进行预测计算及校验计算,结果都是良好的。此外,对杭州湾强潮和涌潮情况下的挟沙力含沙量也进行了校验计算,结果也非常满意。