回流区水流运动三维数值模拟

建立了三维有限元水流模型,模型中采用了高分辨率计算格式。依此模型计算了突扩引起的回流,获得的掺混区流速分布和回流区固定点水位、流速非恒定过程与实测结果基本一致。     

大众轿车无分电器点火系统故障诊断与检修

阐述无分电器点火系统的分类与基本原理,以奥迪A6为例介绍大众轿车无分电器点火系统的构成、故障诊断与检修方法。     

Planktonic community structure and carbon cycling in the Arabian Sea as a result of monsoonal forcing: the application of a generic model

The Arabian Sea exhibits a complex pattern of biogeochemical and ecological dynamics, which vary both seasonally and spatially. These dynamics have been studied using a one-dimensional vertical hydrodynamic model coupled to a complex ecosystem model, simulating the annual cycle at three contrasting stations. These stations are characterised by seasonally upwelling, mixed-layer-deepening and a-seasonal oligotrophic conditions, respectively, and coincide with extensively measured stations on the two JGOFS ARABESQUE cruises in 1994. The model reproduces many spatial and temporal trends in production, biomass, physical and chemical properties, both qualitatively and quantitatively and so gives insight into the main mechanisms responsible for the biogeochemical and ecological complexity. Monsoonal systems are typified by classical food web dynamics, whilst intermonsoonal and oligotrophic systems are dominated by the microbial loop. The ecosystem model (ERSEM), developed for temperate regions, is found to be applicable to the Arabian Sea system with little reparameterisation. Differences in in-situ physical forcing are sufficient to recreate contrasting eutrophic and oligotrophic systems, although the lack of lateral terms are probably the greatest source of error in the model. Physics, nutrients, light and grazing are all shown to play a role in controlling production and community structure. Small-celled phytoplanktons are predicted to be dominant and sub-surface chlorophyll maxima are robust centers of production during intermonsoon periods. Analysis of carbon fluxes indicate that physically driven outgassing of CO₂ predominates in monsoonal upwelling systems but ecological activity may significantly moderate CO₂ outgassing in the Arabian Sea interior.     

铁路旅客周转量的改进等维新息模型预测

铁路旅客周转量预测不仅影响铁路客运计划组织工作,它还体现了客运市场中铁路运输的市场控制力。针对灰色模型对数据的要求,采用滑动平均处理和对数化处理原始数据,并采用等维新息模型对铁路旅客周转量进行预测,通过与实际情况和GM(1,1)模型的预测效果的对比可以发现,该模型可以通过检验并且预测效果良好。     

HXD1型机车制动空气管路冲脱分析及改进方案

根据橡胶密封式管接头的作用原理和使用要求，对HXD1型机车制动空气管路冲脱故障产生的原因进行分析。从结构上对橡胶密封式管接头进行改进，并提出采用卡套式管接头代替橡胶密封式管接头的建议。     

基于CPLD的0.01s计时器设计

本设计提出了一种基于CPLD的0.01S计时器的设计方案。应用高速集成电路以硬件描述语言VHDL语言描述,采用Altera公司的可编程逻辑器件(CPLD)EPM7064SL84实现的现代智能计时仪表,为广大用户提供了方便。系统具有可靠性高,便于功能扩展,成本低,易普及等优点。     

The shoaling of nutrient-enriched subsurface waters as a mechanism to sustain primary productivity off Central Baja California during El Niño winters

Using CalCOFI data for coastal shallow stations (above 100 m depth), higher than expected nitrate concentrations were detected in near-surface high-temperature waters off of Central Baja California during some El Niño winters. Though recent data are not available for Central Baja California, past El Niño data, though limited, showed nitrate concentrations above 16 μM at temperatures above 16 °C, and nitrate concentrations between 1 and 2 μM at 19 °C, while the previously established relationship of temperature and nitrate for California Current waters predicts nitrate depletion above 14 or 15 °C. The anomalous, high temperature–high nitrate enrichment events documented in Central Baja California were detected as shallow as 9 m and as deep as 73 m, were associated with low-oxygen (between 2 and 4 ml/l) and high-salinity (between 33.8 and 34.3 psu) waters, and occurred during the winter months of an El Niño year. Using recent data for San Diego, CA, similar but weaker enrichment events were detected for the El Niño winter of 1997–1998. The periodic shoaling of a subsurface subtropical water mass of high temperature, high salinity, low oxygen and high nutrients during some El Niño winters is proposed to cause periodic enrichment and to maintain productivity during warming events in this area. Enrichment events were not detected off Ensenada, in Northern Baja California, possibly due to the amplification of the onshore flow during El Niño there, or due to the Ensenada front. The proposed mechanism of periodic enrichment of nutrient-depleted surface waters during some El Niño winters by subsurface waters from the California Undercurrent may explain the following: (1) survival of giant kelp forests at their southern limit in Central Baja California documented during past El Niño events in warm waters, (2) the rapid recovery and high carrying capacity of giant kelp documented after the mass disappearance during El Niño 1997–1998, and (3) the increase in the extent of mesotrophic chlorophyll detected in the area during the 1997–1998 and 1982–1983 El Niño events.     

求解多峰性函数全局最优解的进化算法及其应用研究

本又针对简单遗传算法（SGA）在解决多峰性函数最优化问题存在的不足，提出了一种分配区间型进化算法，能够求出多峰性函数所有全局最优解及多个局部最优解。通过十几个多峰性函数与工程实例的数值实验，验证了算法的正确性。对简易海洋平台进行了疲劳可靠性优化设计为算例，取得了满意的结果。     

桥面铺装防水粘结层材料类型的选择

文章针对沥青混凝土桥面铺装结构的防水粘结层性能受到桥梁类型、荷载条件和工作环境等因素影响而难于选择的问题,对各类桥面铺装防水粘结层的使用条件和结构性能进行了研究,分析了各种结构性胶黏剂的物理性质和化学性质及工艺条件,据此制定了桥面铺装防水粘结材料的选择依据,并提出了一种性能较好的粘结剂典型配方。     

插电式混合动力汽车高电压部件设计及布置

根据整车设计要求,建立插电式双电机MG1/MG2+行星轮系混合动力汽车高电压系统方案模型。通过理论计算及工程分析确定高压电池组、高电压线缆、双电机MG1/MG2、变频器(转换器/逆变器)、空调压缩机等高电压部件的结构及关键参数。针对高电压部件布置的安全及可靠性提出建议。