直读式测流仪的常见故障排除方法

本文简单介绍了ZLS-1型直读式流速仪显示器和ZSX-1型直读式流速流向仪的基本工作原理,并根据多次水文测验中所遇到的常见故障,总结了排除它的方法。     

直读式流速仪升级的使用维修对策

通过对比、分析国产ＺＳＸ系列直读式流速仪Ⅰ和Ⅱ型显示器的不同之处,介绍它们的兼容方法,使之因仪器升级而被淘汰的流速仪资源被充分地利用。     

一种新型便携式旋桨流速仪

介绍了一种新型BH-1型便携式旋桨流速仪,主要由自主研制的流速传感器、手持式主机及微机数据回放处理软件三部分组成.其传感器采用独特的导流筒和导流罩结构设计,增加了系统的抗干扰能力,有效提高了测量准确性.应用单片机技术实现了数据的实时检测与处理,多路存储以及瞬时测量流量功能.通过静态试验标定,表明该流速仪测量范围(0.04～4)m/s,非线性误差为0.874%.该流速仪结构新颖、使用轻巧方便、稳定可靠,已广泛应用于国家海洋局对陆源入海排污口排污监测和海洋环境管理工作中.     

流速“T”测量法——介绍LSY-89A电脑流速仪

流速测量是水工模型试验中最重要,也是最基本的测量参数之一。流速测量中使用的仪器有旋桨光电式流速仪、超声流速仪,电磁流速仪、激光流速仪等,由于旋桨光电式流速仪价廉而实用,因此水工试验中使用非常广泛。 旋桨光电流速仪一般常用单位时间里计脉冲数的方法,即用频率测量法,简称“F”     

SLC9-2型直读式海流计的工作原理及维护使用

直读式流速仪在江河湖海的水文实验中得到了广泛的应用。本文介绍了SLC9-2型直读式海流计的基本结构、工作原理、使用和维护的经验。     

LGY-Ⅲ型智能测沙颗分仪

介绍了应用于多项国家重点科技攻关项目——泥沙河工模型试验的ＬＧＹ－Ⅲ型智能测沙颗分仪的工作原理和应用方法。     

循环水筒检定海流仪

一、引言大家知道,“直线明槽”(静水槽)至今仍是国内外检定内河流速仪及海流仪的传统设备。它是将拖曳设备高精度匀速运动的不同量值传递给流速仪或海流仪。实际上海流仪是用来测量流动海水的流速。为更符合实际测量环境,拟采用一个人为造就的均匀、稳定的流场(动水槽)来作为海流仪检定设备。     

SLC9—2型直读式海流计的工作原理简述及维护使用经验

直读式流速仪在江河湖海的水文实验中得到了广泛的应用。介绍 SLC9- 2型直读式海流计的基本结构、工作原理及使用和维护的经验 ,对于水文工作者将有所帮助。     

长江河口北槽抛泥作业状态下的悬沙浓度分布与扩散过程

在长江河口北槽抛泥过程中，应用ASSM－Ⅰ型声学悬浮泥沙观测系统观测悬沙浓度的时空分布规律，结合多普勒流速剖面仪走航式断面流速测量。研究发现：（1）泥沙浓度垂向分布形成至少三种结构类型，即上小下大的“L”型和指数型，上大下小的“漂浮”型；（2）受抛泥泥沙输移的影响，断面流场形成低流速区，或分布在水体表、中层，或贯穿整个水体，形成流速切变锋，它们的强度随抛泥泥沙输移扩散逐渐减弱；（3）在落潮流和颗粒重力共同作用下，抛泥泥沙同时存在输移扩散和沉降过程。小潮型抛泥泥沙主要就近扩散和沉降，中潮和大潮型抛泥泥沙输移扩散范围较远。     

CS—500型智能回声测深仪在长江三峡河段的综合测验

本文通过ＣＳ－５００型智能回声测深仪与ｍｓ－４８型（英国产）回声测深仪在长江三峡河段的同步测验，对ＣＳ－５００型智能回声测深仪的仪器性能，测深精度，智能化程度以及整机可靠性进行了综合检验，检验结果认为，ＣＳ－５００型智能回声测深精度优良，自动化程度高，是目前取代普通回声测探仪在长江三峡河段测深的新一代测深产品。     

Microbial Biomass and Organic Nutrients in the Deep-Sea Sediments of the Central Indian Ocean Basin

In order to assess the impact of deep-sea mining on the in situ benthic life, we measured the microbial standing stock and concentration of organic nutrients in the deep-sea sediments of the Central Indian Ocean Basin in the Indian pioneer area. Sediments were collected using box core and grab samples during September 1996. The total bacterial numbers ranged from 10 10 -10 11 cells per g -1 dry weight sediment. There was a marginal decrease in the number of bacteria from surface to 30 cm depth, though the subsurface section registered a higher number than did the surface. The highest numbers were encountered at depths of 4-8 cm. The retrievable number of bacteria were two orders less in comparison with the direct total counts of bacteria. An almost homogeneous distribution of bacteria, total organic carbon, living biomass, and lipids throughout the depth of cores indicates active microbial and benthic processes in the deep sea sediments. On the other hand, a uniform distribution of total counts of bacteria, carbohydrates, and total organic carbon in all the cores indicates their stable nature and suggests that they can serve as useful parameters for long-term monitoring of the area after the benthic disturbance. Further studies on temporal variability in this region would not only verify the observed norms of distribution of these variables but would also help to understand restabilization processes after the simulated benthic disturbance.     

Assessing the Validity of Seismo-Acoustic Predictor Equations for Obtaining Seabed and Sub-Surface Sediment Physical Properties

The interdependence between the seismo-acoustic properties of a marine sediment and its geotechnical/physical parameters has been known for many years, and it has been postulated that this should allow the extraction of geotechnical information from seismic data. Though in the literature many correlations have been published for the surficial layer, there is a lack of information for greater sediment depths. In this article, a desktop study on a synthetic seafloor model illustrates how the application of published near-surface prediction equations to subsurface sediments (up to several tens of meters burial depth) can lead to spurious predictions. To test this further, acoustic and geotechnical properties were measured on a number of sediment core samples, some of which were subjected to loading in acoustically-equipped consolidation cells (oedometers) to simulate greater burial depth conditions. For low effective pressures (representing small burial depths extending to around 10 meters subsurface), the general applicability of established relationships was confirmed: the prediction of porosity, bulk density, and mean grain size from acoustic velocity and impedance appears generally possible for the investigated sedimentary environments. As effective pressure increases through, the observed relationships deviate more and more from the established ones for the near-surface area. For the samples tested in this study, in some instances increasing pressure even resulted in decreasing velocities. There are several possible explanations for this abnormal behavior, including the presence of gas, overconsolidation, or bimodal grain size distribution. The results indicate that an appropriate depth correction must be introduced into the published prediction equations in order to obtain reliable estimates of physical sediment properties for greater subsurface depths.     

Geoacoustic Inversion via Genetic Algorithm and Its Application to Manganese Sediment Identification

An acoustic inversion method using a wide-band signal and two near field receivers is proposed and applied to multiple layered seabed models including a manganese sediment. The inversion problem can be formulated into a probabilistic model comprised of signals, a forward model, and additive noise. The forward model simulates wide-band signals, such as chirp signals, and is chosen to be the source-waveletconvolution plane wave modeling method. The wavelet matching technique, using weighted least-squares fitting, estimates the sediment sound-speed and thickness on which determination of the possible numerical ranges for a priori uniform distribution is based. The genetic algorithm is applied to a global optimization problem to find a maximum a posteriori solution for determined a priori search space. Here the object function is defined by an L 2 norm of the difference between measured and modeled signals. Not only the marginal pdf but also its statistics are calculated by numerical evaluation of integrals using the samples selected during importance sampling process of the genetic algorithm.     

海上大直径钢管桩打桩过程中桩周土强度弱化研究

海上大直径钢管桩打桩过程中,桩周土体受到强烈扰动而发生强度弱化,掌握桩周土体强度弱化规律对于准确预测打桩过程、保证工程安全具有重要意义。为研究土体强度弱化规律,开展了环剪试验模拟打桩对桩周土体的扰动,测试土体强度随剪切速率的变化规律,建立了描述土体强度弱化规律的拟合公式,引入到打桩分析软件中。研究结果表明：土体的强度折减程度不仅与土体本身的性质有关还受到土体的埋深和剪切速率的影响,埋深越深土体强度折减程度越低,剪切速率越高土体强度折减越高,在打桩分析中可采用这里推荐的线性折减方法来模拟不同深度处土体强度的折减规律。     

Interannual Sea Level Variations and Annual Tides in the Northwestern Pacific

Specific properties of the interannual sea level variations and annual tides in the Northwestern Pacific were studied. Several tide stations were monitored. The monthly mean sea level for the year of 1995 was analyzed at each tide station. A seismic event in 1995, some tectonic activity around the subject area, and the Kuroshio (the oceanic western boundary current) may possibly contaminate results which would have occurred from the astronomical annual tide alone.     

Flow Cytometric Analysis of Coastal Lagoon Bacterioplankton and Picophytoplankton: Fixation and Storage Effects

The effect of different fixation and storage protocols on the flow cytometric (FCM) simultaneous analysis of bacterioplankton and phytoplankton in coastal seawater samples (Mediterranean coastal lagoons) was investigated. FCM measurements (cell number, fluorescence and scatter characteristics) were obtained through DAPI staining. Three fixatives [glutaraldehyde (GA), formaldehyde (FA) and paraformaldehyde (PFA)] and two storage (3 months duration) methods (5 °C and −196 °C) were tested. Two dominant populations were detected in studied samples: bacteria and eukaryotic picophytoplankton. Adding fixatives (2% final concentration) appears necessary to obtain FCM exhaustive counts of all the bacteria and phytoplanktonic cells. This was related to the permeation effect of fixatives which allowed a better DAPI staining of the cells. Maximum fluorescence, i.e. optimal staining of the cells was obtained with FA or PFA, and significant lower fluorescences with GA. Fixed samples stored at 5 °C induced rapid cell loss. Only storage in liquid nitrogen of samples fixed with FA or PFA, allows mid-term (≥4 months) preservation of bacteria or picophytoplankton cell numbers, and limited evolution of DAPI-induced fluorescence and scatter characteristics.     

INFORMATION FOR AUTHORS

<正>Acta Oceanologica Sinica(AOS)is a comprehensive academic journal edited by the Editorial Committee of Acta Oceanologica Sinica and is designed to provide a forum for important research papers of the marine scientific community which reflect the information on a worldwide basis.The journal publishes scholarly papers on marine science and technology,including physics,chemistry,biology,     

Deep-Sea Sediment Compression Curves: Some Controlling Factors, Spurious Overconsolidation, Predictions, and Geophysical Reproduction

Oedometer tests have been carried out on 70 undisturbed surficial clays (at approximately 250 mm below the mudline), mostly collected by free-fall corers from sites widely scattered throughout the deep-sea North Atlantic. Acoustic measurements were also made, initially on contiguous samples and ultimately on the same sample using a geophysically instrumented oedometer which also collected electrical resistivity data. Apart from those quiescent areas below the carbonate compensation depth, such as north of the West Indies where very fine clays exist, most of the samples are silty clays whose geotechnical-geophysical properties are dependent on the type of clay minerals present (and their ability to take in moisture), the sand-size fraction, and the quantity of carbonate present. Thus the pure clays have high compressibilities which decrease on the addition of coarse particles, while the converse is true for the acoustic parameters, these increasing with the sand fraction. Using the notion of the intrinsic compression line for all samples, and comparison to it of the measured compression curves, it is clear that, contrary to some previously held ideas, most deep-sea clays are normally consolidated; the addition of carbonate has the effect of creating an open, stronger sediment skeleton. Interestingly, where information is available, the variation with depth of a sample's acoustic velocity follows the void ratio pressure relationship of the compression curve. This allows the construction of an in-situ sediment compression curve using the in-situ geophysical observations.