Changes in the shelf macrobenthic community over large temporal and spatial scales in the Bohai Sea, China

Over the past 20 years, the Bohai Sea has been subjected to a considerable human impact through over-fishing and pollution. Together with the influence of the Yellow River cut-off, the ecosystem experienced a dramatic change. In order to integrate available information to detect any change in macrobenthic community structure and diversity over space and time, data collected during the 1980s and the 1990s from 3 regions of the Bohai Sea (Laizhou Bay, 16 stations, 37–38°N, 119–120.5°E; central Bohai Sea, 25 stations, 38–39°N, 119–121°E; eastern Bohai Bay, 12 stations, 38–39°N, 118.5–119°E) were reanalyzed in a comparative way by means of a variety of statistical techniques. A considerable change in community structure between the 1980s and the 1990s and over the geographical regions at both the species and family level were revealed. After 10 years, there was a considerable increase in abundance of small polychaetes, bivalves and crustaceans but decreased number of echinoderms. Once abundant in Laizhou Bay in the 1980s, a large echinoderm Echinocardium cordatum and a small mussel Musculista senhousia almost disappeared from the surveying area in the 1990s. Coupled with the increased abundance was the increased species richness in general whereas evenness was getting lower in central Bohai Sea and Bohai Bay but increased in Laizhou Bay. K-dominance plot showed the same trend as evenness J′. After 10 years, the macrobenthic diversity in the Bohai Sea as a whole was slightly reduced and a diversity ranking of central Bohai Sea > Laizhou Bay > eastern Bohai Bay over space was also suggested. Sediment granulometry and organic content were the two major agents behind the observed changes.     

Effect of Cu Co-doping on the magnetism of Zn0.95Co0.05O films

Zn_0.95?x Co_0.05Cu _x O (atomic ratio, x = 0?C8%) thin films are fabricated on Si(111) substrate by reactive magnetron sputtering method. Detailed characterizations indicate that the doped Cu ions substitute the Zn²⁺ ions in ZnO lattice. The doped Cu ions are in +1 and +2 mixture valent state. The ferromagnetism of the Zn_0.95?x Co_0.05Cu _x O film increases gradually with the increase of the Cu⁺ ion concentration till x = 6%, but decreases for higher Cu concentration. Experimental results indicate that the increase of ferromagnetism is not owing to the magnetic contribution of Cu⁺ ions themselves, but owing to the enhancement of magnetic interaction between Co²⁺ ions, which suggests that p-type doping of Cu⁺ ions plays an important role in mediating the ferromagnetic coupling between Co ions.     

基地直达车流组织优化

铁路基地直达货物运输对于加快货物送达、加速车辆周转、缓解编组站能力紧张、降低运输成本等具有重要意义。本文在分析基地直达列车开行的必要条件,以及车流以直达或非直达形式输送,在装、运、卸、储各环节的费用消耗基础上,对基地直达车流组织问题进行了研究,构建了基地直达车流组织优化的非线性0-1规划模型。模型中充分考虑了车流在直达基地的各种组合方案,将运输与库存成本纳入同一目标函数,以物流系统成本最优为目标、以直达列车开行的唯一性条件和必要条件为约束来确定基地车流组织方案。构建的模型能够全面地描述直达基地车流的各种组合,符合我国直达货物运输实际,进一步拓宽了铁路车流组织的研究领域。最后给出的构模实例对模型的有效性、合理性进行了进一步的验证。     

基于VC++和Matlab的C_0-C_0轴悬式机车轴重转移编程计算

主要分析了C0-C0轴悬式机车的轴重转移计算原理和公式,然后运用MATcom接口软件把Matlab编写的M文件转化为C++代码,在VC++中实现C0-C0轴悬式机车轴重转移计算程序。     

一种新型FLASH芯片K9F1G08U0M的应用

本文介绍了一种大容量NAND Flash芯片K9F1G08U0M及其在uPSD3212C型单片机系统中的应用。笔者完成了硬件接口设计和软件设计,给出了硬件连接图和部分程序代码。     

工业园区地下式污水处理厂工程设计

小型地下式污水处理厂在工业园区污水处理中应用越来越多。以某光电产业园区污水厂为例,该厂建设规模为3万m^3/d,全地下式,采用高效沉淀+A^2/O+MBR工艺,出水执行《城镇污水处理厂污染物排放标准》(GB 18918-2002)一级A标准。介绍了该厂污水、污泥处理工艺和主要处理构筑物的设计参数,并总结工程特点。     

Cross-shelf circulation and phytoplankton distribution at the summertime New England shelfbreak front

We investigate aspects of the secondary (cross-shelf) circulation at the Middle Atlantic Bight shelfbreak front using high-resolution data collected on the New England Shelf in August 2002. The alongshore shelfbreak jet coincides with the front at the seaward edge of the cold pool (remnant winter shelf water) and there is a suggestion of a cross-stream convergence centered at the jet core. Despite indications of convergence we found no evidence of a surface subduction on the seaward side of the front. At depth 70 m near the shelfbreak there was a patch of chlorophyll, located within a local temperature–salinity maximum which, though significantly below the euphotic zone, appeared to be photo-acclimated and viable. The chlorophyll feature could be the result of a local subduction by a larger scale eddy circulation seaward of the front.Dye tracer experiments directly observed the convergence at the foot of the shelfbreak front and subsequent upwelling of bottom boundary layer water along the shoreward side of the shelfbreak front. But, we found no evidence that this upwelling influenced productivity at the front. Further, since there was no cross-shelf maximum in subsurface chlorophyll at the front, we conclude that this productivity is in general, sustained by a broadly distributed local vertical nutrient flux from an underlying nutrient reservoir.     

Real time assimilation of HF radar currents into a coastal ocean model

A real time assimilation and forecasting system for coastal currents is presented. The purpose of the system is to deliver current analyses and forecasts on based on assimilation of high-frequency radar surface current measurements. The local Vessel Traffic Service monitoring the ship traffic to two oil terminals on the coast of Norway received the analyses and forecasts in real time.A new assimilation method based on optimal interpolation is presented where spatial covariances derived from an ocean model are used instead of simplified mathematical formulations. An array of high frequency radar antennae provides the current measurements. A suite of nested ocean models comprises the model system. The observing system is found to yield good analyses and short range forecasts that are significantly improved compared to a model twin without assimilation. The system is fast, analysis and 6-h forecasts are ready at the Vessel Traffic Service 45 min after acquisition of radar measurements.     

不同应力路径下黏性土的力学特性研究

对上海地区⑤1层软黏土进行了常规三轴、减压三轴试验，以研究考虑不同应力路径的力学特性。分析了初始固结状态对软黏土应力路径的影响，比较了不同应力路径下土体的应力-应变关系特征和孔隙水压力变化规律，计算了土体抗剪强度指标。研究结果表明，应力路径对土的峰值强度、孔压、有效应力路径等特性影响很大，软粘土的应力-应变关系具明显的非线性,且基本呈应变硬化型；常规三轴试验中孔隙水压力为正值，减压三轴试验中总体为负值；初始固结状态对黏土的抗剪强度有一定的影响，且影响主要来自对黏聚力值上，对内摩擦角值影响较小。     

应用模糊数学及AHP分析法优化铁路物流结构

结合铁路物流特殊性,分析现有合作企业的评价、优选方法在定性因素量化分析上的不足,提出应用模糊数学方法量化分析与评价候选企业的兼容性,利用层次分析法量化评价其素质的优劣,将量化结果与定量指标一起带入全局优化求解。使定性因素和定量因素在全局优化中结合起来,并应用(0 1)目标规划模型得到最优合作组合。通过算例证明该方法在优化铁路物流结构中的有效性。