Characterization of subduction initiation

Compression is required for all kinds of subduction initiations, which may cause either subsidence or uplift, depending on the ages of the oceanic plates. Subduction initiations associated with the old oceanic crust tend to amplify preexisting subsidence by compression, whereas those associated with young oceanic plates may result in uplift.

     

Variability of subduction rates of the subtropical North Pacific mode waters

The climatology subduction rate for the entire Pacific is known, but the mechanism of interannual to decadal variation remains unclear. In this study, we calculated the annual subduction rates of three types of North Pacific subtropical mode waters using a general circulation model (LICOM1.0) for the period of 1958-2001. The model experiments focused on interannual variations of ocean dynamical processes under daily wind forcings and seasonal heat fluxes. The mode water formation region was defined by a potential vorticity minimum at outcrop locations. The model results show that two subduction rate maxima (>100 m/a) were located in the Subtropical Mode Water (STMW) and the Central Mode Water (CMW) formation regions. These regions are consistent with a climatologically calculated value. The subduction rate in the Eastern Subtropical Mode Water (ESTMW) formation region was smaller at about 75 m/a. The subduction rate shows clear interannual and decadal variations associated with oceanic dynamic variabilities. The average subduction rate of the STMW was much smaller during the period of 1981-1990 compared with other periods, while that of the CMW had a negative anomaly before 1975 and a positive anomaly after 1978. The variability agreed with Ekman and geostrophic advections and mixed layer depths. The interannual variability of the subduction rate for the ESTMW was smallest during 1970-1990, as a result of a weak wind stress curl. This paper explores how interannual signals from the atmosphere are stored in different parts of the ocean, and thus may contribute to a better understanding of feedback mechanisms for the Pacific Decadal Oscillation (PDO) event.     

断裂带和俯冲带中石墨碳质物的地质过程与碳循环意义

碳是自然界中常见的一种元素,其以单矿物(如石墨、金刚石)、化合物形式(如碳酸盐、二氧化碳)及生物体中的有机碳等多种形式存在。随着越来越多的深入研究,碳质物或石墨化的作用和地位也引起了广泛的关注。石墨碳质物出现在不同地壳深度的断裂带或俯冲带岩石中,特别是在一些大地震断裂带中富集。在地质变质作用过程中,随着温度的增加,非晶形碳质物转变为晶形有序化的石墨,且其石墨化过程不可逆,因此其拉曼光谱峰可定量记录峰期变质作用温度;同时,在变形过程中,石墨的特殊结构性能和力学属性能有效降低岩石强度,促进塑性变形,在快速滑动面或地震滑动面中,起到固体润滑剂作用,因此,地壳中的石墨物质对于岩石强度弱化和地震断裂滑动及演化过程具有重要意义。石墨碳质物具有低溶解性和低移动性,常作为碳汇稳定存在于深部地壳中,在地质时间尺度上,一旦碳及石墨化共同参与到岩石中,一些主要的地质过程(如俯冲作用、断裂作用、风化侵蚀、生物作用)致使石墨碳质物通过形成和破坏过程富集或释放碳到地球表面(大气圈),将显著地影响碳循环。      

铜冶店-孙祖断裂成因机制与控岩控矿研析

铜冶店孙祖断裂展布方向与区域上基底岩石的条带展布方向一致,该断裂规模巨大,总体上分为6段,作为构造单元边界的分划性断裂往往深切上地幔或下地壳,从而成为深部岩浆和矿液的上升通道。它控制着该区成矿带或成矿区的分布,金牛山岩体、矿山岩体、铁铜沟岩体、铜井岩体等中基性—中性—中偏碱性(中偏酸性)杂岩体亦是受铜冶店孙祖及其次级断裂或与其他构造复合部位控制。该断裂经历了多期活动,早期活动控制着两侧地质体的分布,晚期活动对各种含矿热液的运移和富集起着不同程度的控制作用,是铁、铜、金矿成矿作用的有机组成部分,“构造、地层、岩体”三要素是形成接触交代(矽卡岩)型铁矿等矿床必不可少的控矿因素。该断裂活动提供了成矿物质和流体迁移、聚集的热力和动力,提供了成矿物质运移和沉淀的空间场所,其所控制的矽卡岩型铁矿床及中低温热液金、铜等矿床,多集中于铜冶店孙祖断裂鹿野前孤山段,该断裂具“构造控矿,分段富集(走向、倾向)”的特点。     

Experiments on exactly computing non-linear energy transfer rate in MASNUM-WAM

The Webb-Resio-Tracy (WRT) method for exact computation of the non-linear energy transfer rate was implemented in MASNUM-WAM, which is a third-generation wave model solving the discrete spectral balance equation. In this paper, we describe the transformation of the spectral space in the original WRT method. Four numerical procedures were developed in which the acceleration techniques in the original WRT method, such as geometric scaling, pre-calculating, and grid-searching, are all reorganized. A series of numerical experiments including two simulations based on real data were performed. The availability of such implementation in both serial and parallel versions of the wave model was proved, and a comparison of computation times showed that some of the developed procedures provided good efficacy. With exact computation of non-linear energy transfer, MASNUM-WAM now can be used to perform numerical experiments for research purposes, which augurs well for further developments of the model.     

焦家构造带控矿作用探讨——以莱州新城金矿床为例

概略陈述了新城金矿床及焦家构造带的基本地质特征.对焦家构造带成矿前后的构造应力场、矿体侧伏规律、NWW向矿化带的形成及成矿时代等问题进行了探索性讨论.     

基于单齿侵入理论的牙轮钻头钻速方程

考虑井底水平地应力、钻井流体压力及地层孔隙压力,基于单齿侵入理论推导单齿侵入井底岩石的侵深公式,建立纯滚动锥形齿、楔形齿和滚动、剪切复合运动锥形齿等牙轮钻头的钻速方程.通过实验分析刃尖角、井底液柱压力对单齿侵入深度的影响,以及转速、轴向载荷对微钻头、牙轮钻头机械钻速的影响.结果表明:随着牙齿刃尖角的增大,锥形齿和楔形齿的侵深呈指数递减趋势;随着井底液柱压力的增大,牙齿侵入深度呈指数递减趋势,其中锥形齿降低速率大.在软到中硬地层中,牙齿侵入深度大,冲击侵入、回转剪切复合破岩方式的破岩效率高;在硬度地层中,牙齿侵入深度小,纯滚动冲击侵入破岩效率高.为分析实钻时牙轮钻头的机械钻速提供计算方法.     

Estimating time-based instantaneous total mortality rate based on the age-structured abundance index

The instantaneous total mortality rate(Z) of a fish population is one of the important parameters in fisheries stock assessment. The estimation of Z is crucial to fish population dynamics analysis,abundance and catch forecast,and fisheries management. A catch curve-based method for estimating time-based Z and its change trend from catch per unit effort(CPUE) data of multiple cohorts is developed. Unlike the traditional catch-curve method,the method developed here does not need the assumption of constant Z throughout the time,but the Z values in n continuous years are assumed constant,and then the Z values in different n continuous years are estimated using the age-based CPUE data within these years. The results of the simulation analyses show that the trends of the estimated time-based Z are consistent with the trends of the true Z,and the estimated rates of change from this approach are close to the true change rates(the relative differences between the change rates of the estimated Z and the true Z are smaller than 10%). Variations of both Z and recruitment can affect the estimates of Z value and the trend of Z. The most appropriate value of n can be different given the effects of different factors. Therefore,the appropriate value of n for different fisheries should be determined through a simulation analysis as we demonstrated in this study. Further analyses suggested that selectivity and age estimation are also two factors that can affect the estimated Z values if there is error in either of them,but the estimated change rates of Z are still close to the true change rates. We also applied this approach to the Atlantic cod(G adus morhua) fishery of eastern Newfoundland and Labrador from 1983 to 1997,and obtained reasonable estimates of time-based Z.     

国家基础地理信息数据库质量控制技术体系建立与应用

针对国家基础地理信息数据库的生产、建库、更新工程中数据质量控制需求,从质量控制指标体系、质量控制技术方法、质量控制软件系统等方面,讲述了数据质量控制技术体系建立的设计思路及关键技术问题,并介绍了其在国家1:50 000数据库更新工程等重大测绘项目中的应用情况。     

岩体边坡影像的控制测量方法研究

控制测量是数字近景摄影测量获取岩体结构面特征点三维信息最关键的环节,其观测结果(结构面特征点三维坐标值)直接影响在内业工作站上所建立的三维模型的精度及岩体结构面信息解译的准确性。以长春市净月北山二采石场边坡为研究对象,采用前方交会法、免棱镜极坐标法及活动控制系统法等3种不同的外业控制测量方法获取边坡控制点的坐标,并以此为依据分别在VirtuoZo工作站上建模,解译裂隙岩体结构面模型特征点的三维信息,并和全站仪现场实测的数据对比,并基于测量误差理论进行精度分析,结果表明3种控制测量方法的点位中误差均在±3cm之内,都能满足数字近景摄影测量中等精度规范对被测目标的点位精度要求。通过现场观测,总结出了3种控制测量方法的优缺点,实际应用时应根据场地情况选择合适的控制测量方法进行建模。     

基于网络的会计信息系统的安全控制

安全问题是会计信息系统的重要问题。探讨了基于网络的会计信息系统在操作系统控制、数据库管理、应用程序等方面的安全控制,并介绍了SQL Server的权限系统。     

准格尔地区粉煤灰中镓的浸出率影响因素研究

为了粉煤灰的高附加值综合利用,采用酸浸法对准格尔地区循环流化床粉煤灰进行了镓的浸出实验研究,考察了多种因素对镓的浸出率的影响,包括粉煤灰粒度,酸的种类与浓度、酸浸温度与时间、固液比等。结果表明,提高镓的浸出率的适宜条件为：粉煤灰粒度200目,盐酸的浓度6 mol/L,酸浸温度应大于160℃,酸浸时间6 h,液固比在5∶1～6∶1之间为宜。在优选的工艺条件下,镓的浸出率可达80％以上。从粉煤灰中提取镓,使其作为一种资源加以利用,是提高粉煤灰综合利用价值的有效途径。     

VR-GIS技术在城市“数字防洪”中的应用

虚拟现实地理信息系统(VR-GIS)是一门综合虚拟现实和地理信息系统特征的新型技术,以此为基础构建的城市数字防洪系统在防洪决策中发挥了积极的辅助作用。本文以哈尔滨城区段三维数字防洪系统的开发为背景,探讨了VR-GIS应用于城市数字防洪的关键技术及其实现方法,包括防洪三维虚拟场景的构建技术,仿真数据库的建立与联合查询,洪水动态模拟等方面的相关技术和实现方法,为数字防洪系统提供了基础研究平台。     

基于DSP6000的实验室安全控制系统研究

以TMS320DM642为核心构建一个实验室安全控制系统,通过摄像机采集视频图像,将图像传输给DM642进行图像处理,包括获取背景图像、差影处理、图像分割、运动目标检测、安全控制,并将处理结果显示在液晶屏上.实验验证,系统能够实现实验室条件下的安全控制.     

基于DSP6000的实验室安全控制系统研究

以TMS320DM642为核心构建一个实验室安全控制系统,通过摄像机采集视频图像,将图像传输给DM642进行图像处理,包括获取背景图像、差影处理、图像分割、运动目标检测、安全控制,并将处理结果显示在液晶屏上.实验验证,系统能够实现实验室条件下的安全控制.     

多级次地下水流系统的最小能耗率原理初探

20世纪60年代初期,Tóth基于定水头上边界条件推导出解析解,得出多级次地下水流系统,是水文地质学里程碑式的突破,成功地解决了一系列理论和实际问题。但Tóth解析解存在的缺陷也长期沿袭：单纯重视数学模拟而忽视物理机制;将地形控制地下水位看成是普适性规律;忽视给定水头上边界数学模拟的失真。这些缺陷,尤其是忽视物理机制探究,不仅妨碍Tóth理论自身发展,而且导致地下水流系统理论尚未被国际水文地质界普遍接受。参照河流动力学中应用的最小能耗率原理,类比提出地下水流最小能耗率的表达式。基于已有的通量上边界地下水流模式数值模拟结果,进一步探究物理机制,归纳得出地下水流系统遵循最小能耗率原理的结论。     

The resuspension rate of sediments in 32°N section on the East China sea

This research on the influence of sediment resuspension on the flux of materials in the margin of the East China Sea showed that the sediment resuspension rates, was 47.40%–79.18% in the surface layers, and 72.75%–96.96% in the bottom layers. The research confirmed that the Changjiang River runoff and the eddy area upwelling flow near 125°E were two important factors affecting the sediment resuspension in summer; the transformation of DOC to POC through the flocculation in the transitional region (123°–124°E) was also confirmed by comparison of the resuspension rate. The sediment resuspension was shown to be influenced by the seasonal factor, especially in the surface layer. Contribution No. 4017 from the Institute of Oceanology, Chinese Academy of Sciences. Project 49636210 supported by NSFC.     

Effect of flow rate on environmental variables and phytoplankton dynamics: results from field enclosures

To investigate the effects of flow rate on phytoplankton dynamics and related environment variables,a set of enclosure experiments with different fl ow rates were conducted in an artificial lake. We monitored nutrients,temperature,dissolved oxygen,p H,conductivity,turbidity,chlorophyll-a and phytoplankton levels. The lower biomass in all flowing enclosures showed that flow rate significantly inhibited the growth of phytoplankton. A critical flow rate occurred near 0.06 m/s,which was the lowest relative inhibitory rate. Changes in flow conditions affected algal competition for light,resulting in a dramatic shift in phytoplankton composition,from blue-green algae in still waters to green algae in flowing conditions. These findings indicate that critical flow rate can be useful in developing methods to reduce algal bloom occurrence. However,flow rate significantly enhanced the inter-relationships among environmental variables,in particular by inducing higher water turbidity and vegetative reproduction of periphyton( Spirogyra). These changes were accompanied by a decrease in underwater light intensity,which consequently inhibited the photosynthetic intensity of phytoplankton. These results warn that a universal critical flow rate might not exist,because the effect of flow rate on phytoplankton is interlinked with many other environmental variables.     

济南城市防汛GIS研究

首先对济南城市防汛GIS系统进行了总体设计,给出了系统的数据库设计,并重点介绍积水模拟模璎的输入输出设计,然后对组件技术、积水模拟模型等系统实现的关键技术进行了阐述,最后介绍了济南城市防汛GIS的特色功能模块.系统运行良好,为济南的城市防汛提供了科学决策的依据.     

基于神经网络的专家系统在温室控制中的应用

为了实现温室控制,针对温室环境的多输入、多输出、非线性和难以建立数学模型等特点,提出一种基于BP神经网络的专家系统并用于温室控制。该方法将传感器采集的温度、湿度等信息输入到神经网络专家系统,在获得决策结果的同时通知控制部分执行相应的决策。这种方法不仅解决了传统专家系统知识获取的瓶颈问题、推理能力差、智能化低的缺点,而且克服了神经网络不具有解释功能的问题。总之,成功实现了神经网络和专家系统功能上的互补,较好的用于温室控制。