Seasonal and interannual variation of physical and biological processes during 1994–2001 in the Sea of Japan/East Sea: A three-dimensional physical–biogeochemical modeling study

A Pacific basin-wide physical–biogeochemical model has been used to investigate the seasonal and interannual variation of physical and biological fields with analyses focusing on the Sea of Japan/East Sea (JES). The physical model is based on the Regional Ocean Model System (ROMS), and the biogeochemical model is based on the Carbon, Si(OH)₄, Nitrogen Ecosystem (CoSiNE) model. The coupled ROMS–CoSiNE model is forced with the daily air–sea fluxes derived from the National Centers for Environmental Prediction (NCEP) and the National Center for Atmospheric Research (NCAR) reanalysis for the period of 1994 to 2001, and the model results are used to evaluate climate impact on nutrient transport in Mixed Layer Depth (MLD) and phytoplankton spring bloom dynamics in the JES.The model reproduces several key features of sea surface temperature (SST) and surface currents, which are consistent with the previous modeling and observational results in the JES. The calculated volume transports through the three major straits show that the Korea Strait (KS) dominates the inflow to the JES with 2.46 Sv annually, and the Tsugaru Strait (TS) and the Soya Strait (SS) are major outflows with 1.85 Sv and 0.64 Sv, respectively. Domain-averaged phytoplankton biomass in the JES reaches its spring peak 1.8 mmol N m^− 3 in May and shows a relatively weak autumn increase in November. Strong summer stratification and intense consumption of nitrate by phytoplankton during the spring result in very low nitrate concentration at the upper layer, which limits phytoplankton growth in the JES during the summer. On the other hand, the higher grazer abundance likely contributes to the strong suppression of phytoplankton biomass after the spring bloom in the JES. The model results show strong interannual variability of SST, nutrients, and phytoplankton biomass with sudden changes in 1998, which correspond to large-scale changes of the Pacific Decadal Oscillation (PDO). Regional comparisons of interannual variations in springtime were made for the southern and northern JES. Variations of nutrients and phytoplankton biomass related to the PDO warm/cold phase changes were detected in both the southern and northern JES, and there were regional differences with respect to the mechanisms and timing. During the warm PDO, the nutrients integrated in the MLD increased in the south and decreased in the north in winter. Conversely, during the cold PDO, the nutrients integrated in the MLD decreased in the south and increased in the north. Wind divergence/convergence likely drives the differences in the southern and northern regions when northerly and northwesterly monsoon dominates in winter in the JES. Subjected to the nutrient change, the growth of phytoplankton biomass appears to be limited neither by nutrient nor by light consistently both in the southern and northern regions. Namely, the JES is at the transition zone of the lower trophic-level ecosystem between light-limited and nutrient-limited zones.     

机械系统故障分析及控制策略研究

文章从工质、材料与零部件方面来分析机械系统的故障机理及控制策略,对掌握系统的故障根源,实施主动性的维修对策是十分有利的。     

SLOPE/W软件总应力法和有效应力法的应用

按简单条分法和简化毕肖普法,通过算例阐述了SLOPE/W软件总应力法和有效应力法的计算原理和应用,指出SLOPE/W软件虽然在输入时没有区别总应力参数和有效应力参数,但结合输入时是否定义孔隙水压力,用户可以从计算方法的原理上来区别软件是按总应力法还是按有效应力法计算.     

基于Matlab／Simulink和VB的直流调速系统仿真研究

在某改造项目中,需要模拟电机、励磁调节器、电压调节器等设备的运行。在PC环境下,通过VB和Matlab／Simulink混合编程模拟设备功能,通过数据采集卡和CAN通讯卡从外围设备采集数据并与控制分系统通讯。该仿真系统充分发挥了Matlab／Simulink的建模优势,以及VB编程能力强和人机界面友好的特点,实现了对设备的很好模拟,在项目中得到成功应用。     

采用B／S模式来实现C／S模式下物资管理系统的优化

本文通过对C／S和B／S模式物资管理系统在使用中优缺点的分析,提出了采用以C／S模式为主,B／S模式为辅的混合模式对当前单一的C／S模式物资管理系统进行改造的设想。在这种混合模式下,物资管理部门内部采用C／S模式,便于实现复杂的管理功能及可靠的安全机制：对于非物资管理部门的用户,采用B／S模式,便于统一管理与维护。最后,本文还对系统改造的开发环境和技术做了探讨。     

国外沥青路面车辙的控制

国外在控制车辙产生的问题上采取的关键做法是提高沥青混凝土的强度,从而提高其抗辙槽能力,应用此种方法可为我国今后类似的施工工程提供参考。     

基于服务质量招投标的出租车市场准入与退出机制

对中国现行出租车市场行政审批、拍卖、定额招标等主要准入模式存在的弊端进行了分析,指出出租车市场准入与退出机制应促进服务质量竞争,促进企业自身建设,促进运营模式改革,并维护行业稳定,建立一个以服务质量招投标为主要手段的出租车市场准入与退出机制,对实施服务质量招投标制度需解决的政策法规配套、服务质量评价体系构建、经营权有偿使用制度改革以及新老政策衔接等关键问题提出了建议。实际应用表明该机制可以较好地化解政府、出租车公司、出租车驾驶员之间的利益矛盾,促进行业自身建设,加强行业服务竞争,提高行业服务水平。     

路面铣刨刀具失效机理与形式分析

对路面铣刨刀具结构组成、切削时象、工作状态和失效机理的进行了简洁的论述。着重分析了刀具正常失效和非正常失效产生的原因．提出了保证刀具正常失效的措施。     

机动车超速行驶防范对策分析

机动丰超速行驶是引起交通事故的主要原因,是严重的道路交通违法行为之一。机动丰超速是由于驾驶人没有及时纠正驾驶过程中的误判、误动的结果。引起超速的原因包括驾驶人、机动车、交通安全设施和其他因素四个方面,应从教育培训、法律、交通安全设施、交通科技四个方面采取措施预防超速。     

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详细探讨了直接反应法制备异丙醇铝过程中单质碘对铝与异丙醇反应的催化机理,得出碘的催化作用在于:碘首先与铝反应生成AlI3,然后AlI3醇解生成异丙醇铝和HI,同时HI与铝反应又生成AlI3和H2.另外对铝与异丙醇的反应中碘的最佳用量以及铝-醇的最佳比例给出了明确的工艺参数.