内高压成形微型车驱动桥壳工艺分析

为了达到节材、节能和提高产品质量的目的,研究成功了利用低合金高强度结构无缝钢管作为毛坯,采用内高压成形技术生产微型汽车驱动桥壳的新工艺,为该工艺的产业化打下基础。     

常熟电厂东线取水隧道长江水下临时封堵墙冻结施工技术

常熟发电有限公司2×1 000 mW机组扩建工程F标段江底东线盾构取水隧道修复施工,技术含量高,施工难度大,国内没有同类工程可以借鉴,江下临时封堵墙冻结技术的成功实施为东线隧道修复后续施工提供了安全保障。详细介绍了填充冻结法施工水下临时封堵墙施工工艺、冻结制冷系统设计及施工监测等技术,可为类似地下冻结工程施工提供借鉴。     

东风标致307发动机怠速不稳动力不足故障诊断

介绍氧传感器结构和工作原理;对东风标致307发动机怠速不稳、动力不足故障进行分析、诊断及排除。     

Decreasing oxygen concentrations in the Gullmar Fjord, Sweden, as confirmed by benthic foraminifera, and the possible association with NAO

The deep Gullmar Fjord on the Swedish west coast may be subject to a trend of decreasing oxygen content of the bottom-water. Due to a non-uniform frequency of oxygen measurements before and after 1980, and small differences in the minimum concentrations, it is difficult to assess with certainty if this is true or not. We have used benthic foraminifera from three ultra-high resolution sediment records to try to find out if such a trend exists. The sediment records comprise the time between 1930 and 1996, with an almost year-based temporal resolution. The foraminiferal records show a significant change in faunal composition during the mid-1970's when it altered from a common Skagerrak fauna to an assemblage characterized by an opportunistic, low oxygen tolerant species; Stainforthia fusiformis. This species is an indicator of low oxygen environments of many Scandinavian fjords. The timing of this faunal change coincides with one of the first recorded severe low oxygen events in the Gullmar Fjord in the winter of 1973/1974. The change suggests that the Gullmar Fjord has actually been subject to a decrease in bottom-water oxygen concentrations. The reason for this change is not clear but here, for the first time, we present sediment records that suggest that there is a causal relation between variations in the North Atlantic Oscillation (NAO) indices and the marine environment. In the early 1970s the NAO-indices altered from a mainly negative phase towards a mainly positive period which is still ongoing. Positive NAO-indices (winter values) in the Skagerrak region are generally marked by westerly winds which normally prevent the exchange of bottom-water in the fjords, i.e., the oxygenation of the sea floor and the supply of oxygen to benthic life.     

Changes in apparent oxygen removal in the Baltic proper deep water

By developing a steady state diagnostic model for a stratified deep-water mass, one is able to quantify both the mass flows and apparent oxygen removal in the Baltic proper deep water. The model is based on continuity of the assumed conservative observable volume, salinity and temperature. Second degree polynomials are fitted to observed vertical profiles of temperature as well as oxygen concentration to give a functional correspondence with the used spatial variable salinity. These relations are used in the model that calculate the water flows, oxygen flows and oxygen removal during four periods between 1959 and 1997. The model forms a boundary value problem, which is solved with a finite difference scheme. The model seems to give reasonable estimates of the flows. The oxygen removal is mainly balanced by inflow of oxygen with incoming water. The oxygen consumption is 4–8 μl O₂ l⁻¹ day⁻¹, which corresponds to a degradation of organic matter in the range 30–60 g C m⁻² year⁻¹.     

氧化锆式氧传感器检测与波形分析

重点从氧化锆式氧传感器的基本工作原理、常见故障、检测方法、波形分析4方面,介绍了氧传感器的使用、故障诊断和维修。     

核潜艇舱室一体化空气再生系统技术设想

本文提出一种核潜艇电催化制氧耦合二氧化碳消除空气再生系统技术设想,该系统以膜电极构型电解反应器为核心,电解反应器中阳极进行水氧化反应制氧,阴极则将二氧化碳电催化还原为甲酸、甲醇等液体产物,实现核潜艇舱室供氧和二氧化碳消除一体化耦合。该系统只需常温常压条件下运行,运行过程中不产生氢气等危险气体副产物,产生的甲酸、甲醇等液体产物易于排放,能够联合集成二氧化碳吸收装置,且无需配套压缩机组。该设计能够改进和提高舱室空气再生系统使用性、安全性和潜艇隐蔽性,进一步提升核潜艇作战能力。     

危重患者心脏手术后氧代谢监测的价值

目的　探讨心脏直视术后危重患者氧供需平衡的重要性和临床价值 .指导救治 ,评估疗效及预后 ,预防多脏器功能衰竭 ( MOF)的发生 ,使 ICU监测水平跨跃到细胞水平 .方法　对 148例心脏直视术后危重患者入 ICU后 ,分阶段动态监测动脉 ,混合静脉血气 ,心输出量 ,胃粘膜 p H值 ,对氧代谢动力学各项监测值之间相关关系进行分析 .结果　动 -静脉血气及其差值的变化与循环 ,呼吸功能变化呈正相关关系 ;APACHE 评分高 ,Sv O2 低的极重患者死亡率明显高于APACHE 评分低 ,Sv O2 偏高的较重患者 ;Phi值的低、高与在 ICU时间、伴发症发生率、预后呈显著相关性 ;A- Vp H,A-V PCO2 与 VO2 依赖 DO2 的发生呈显著负相关性 .结论　动态观察氧供需及分析 DO2 ,VO2 两者之间的相关关系 ,能真正反映机体氧合情况 ;维持全身氧供需平衡是氧代谢监测的关键 ;维持局部组织器官氧供需平衡是预防 MOF的根本     

Relationships between near-bottom dissolved oxygen and sediment profile camera measures

The United States Environmental Protection Agency (U.S. EPA) and other environmental authorities regulate concentrations of dissolved oxygen (DO) as a measure of nutrient-related eutrophication in estuarine and coastal waters. However, in situ DO concentrations are extremely variable, and their characterization requires an extensive sampling program to provide data over meaningful scales of time and space. In contrast, benthic faunal communities integrate the impacts of low DO over time, and can be rapidly assessed using benthic imaging. The goal of this study was to quantify the relationships between near-bottom dissolved oxygen and measures derived from benthic imaging with a sediment profile camera. We monitored three stations in Narragansett Bay (Rhode Island, USA) for DO and other water quality parameters 15–20 cm above the sediment surface on 15-minute intervals between July and November 2002, and regularly sampled these stations with a sediment profile camera throughout this time period. These soft-sediment stations encompassed several DO environments. We tested for relationships between near-bottom DO and several camera measures, including Nilsson and Rosenberg's Benthic Habitat Quality (BHQ) index, the apparent Redox Potential Discontinuity (aRPD) depth, and various faunal features that can be identified in sediment profile images. Camera measures were examined against a variety of methods of characterizing DO (including mean DO, and the percent of time under various DO thresholds), over a span of time scales from 1 day to 49 days. The best relationship (highest r²) between near-bottom DO and BHQ was found when DO was evaluated as the percent of time under a hypoxic threshold of 2.6 mg l^− 1 over a 28-day time scale (by examining DO records over the 28 days preceding each camera deployment). We found that, over several benthic settings, the BHQ index was successful at identifying environments that had experienced relatively high or low DO over the preceding four weeks. Our sediment profile data showed more variability with DO in the intermediate values of BHQ. We conclude that sediment profile camera measures correlate to DO in areas where low DO is the primary stressor, integrate DO over ecologically relevant time scales, and enable sampling over spatial scales that are meaningful for mapping by virtue of rapid deployment and analysis. We submit that sediment profile camera imagery is a useful assessment and mapping tool for environmental managers interested in benthic condition and in first-order quantitative estimates of near-bottom DO regimes in areas where low DO is the primary benthic stressor.     

大掺量掺合料高性能混凝土在宁波港的应用

介绍大掺量掺合料高性能混凝土的原材料、配合比设计、施工工艺及在宁波港的应用情况,为提高海工结构混凝土耐久性提供借鉴。