汽油车三效催化转化器内废气转化率的数值模拟

基于三效催化转化器内十三反应机理的反应速率方程以及气相和固相的质量平衡和能量平衡原理,建立了三效催化转化器的废气转化率数学模型,通过对其进行数值模拟,得到转化率随氧化还原比的变化情况,计算值与实验值吻合良好。研究对提高三效催化转化器转化率具有重要的参考价值。     

"4·23"海上外轮非法过驳事件带来的启示

本文通过对"4·23"海上外轮非法过驳作业事件的跟踪,分析海上非法过驳作业存在的安全隐患,考察相关立法对海上过驳作业的规定及存在的问题,并从源头管理、制度建设、监管能力建设等方面提出液货船舶海上过驳管理建议。     

废旧沥青混合料性能研究

对废旧沥青混合料中回收沥青的化学结构、流变性能和废旧沥青混合料中沥青变异性、级配变异性进行试验分析,综合评价了废旧沥青混合料的性能。     

基于Excel-Mars2000-Isight平台的油船中横剖面结构尺寸优化

散货船和油船共同结构规范(CSR)规定了船体梁总纵强度、局部强度、屈曲强度、疲劳强度等要求。目前,对油船中横剖面结构尺寸优化的研究较多,但设计约束条件通常比较简单,较少考虑CSR中的多种约束条件和载荷,因此优化结果的实用性有待商榷。由于CSR规范条文较繁琐且不断更新,考虑利用船级社规范校核软件进行符合描述性要求的规范计算,在通用优化平台Isight中集成Mars2000软件,实现剖面尺寸自动优化。根据上述优化思路和流程,开发了基于Excel-Mars2000-Isight平台的油船中横剖面结构优化工具。     

Weathering sources in the Gaoping (Kaoping) river catchments, southwestern Taiwan: Insights from major elements, Sr isotopes, and rare earth elements

This study aims at quantifying the distribution of REEs associated with chemical weathering processes, as well as investigating weathering mechanisms and source regions of the Gaoping (formerly spelled Kaoping) River (KPR) catchment basin located at southwestern Taiwan. Spatial distributions of dissolved rare earth elements, as well as major ions, trace elements and Sr isotopes in river waters were analyzed using SF-ICPMS and TIMS. Our results indicate that REE concentrations and patterns predominantly reflect sources and intensity of chemical weathering along the river's catchment. Most specimens have high Na/Cl (4.2–30.1 mol/mol) ratios due to strong weathering intensity in the upper stream. The Na/Ca and Mg/Ca ratios suggest the main contribution is from weathering of silicates and carbonates. Total concentrations of REEs are rather low in the Gaoping (Kaoping) River (6.7–15.4 ng/L), possibly influenced by adsorption onto suspended particles. The REE patterns also reflect source heterogeneity in weathering minerals with large LREE depletion and MREE enrichment. Europium is strongly enriched in the Gaoping (Kaoping) River water, as a result of its preferential dissolution from suspended particles. Unique Gadolinium anomaly is present in all specimens, likely related to contamination due to clinic waste disposal. Small fractionations of LREE/HREE have occurred along the KPR and can be used as a distinct signature for source identification. The main stream samples exhibit a relatively wide range of ⁸⁷Sr/⁸⁶Sr, 0.71265–0.71360, with a systematical increase downstream due to source mixing of dissolved basalt (less radiogenic) and sedimentary rocks. Each tributary shows distinct Sr isotope signatures due to different rock types and ages. These isotopic and elemental compositions provide important information on weathering source and erosion budget.     

Valuing cargo flexibility in oil transportation

The seaborne oil transportation market is served by two main types of vessels—crude oil tankers and product tankers. Product tankers are designed to move refined oil products, yet they can also opportunistically carry ‘dirty’ products such as crude and heavy fuel oil, subject to the cost of tank cleaning when re-entering the clean products trade. We apply an entry-exit real option model with a stochastic freight rate differential to derive optimal triggers for switching between the two cargo types and estimate the value of the switching option. We show that the value of active switching has grown over time, and generally exceeds the additional construction cost of a product tanker. Our findings are important both from a practical point of view and for our understanding of market integration in the tanker freight market. Specifically, shipowners can use our model as a basis for optimizing chartering policy for clean product tankers. We also show that there are periods where the dirty market is persistently stronger, and discuss the possible reasons for such apparent inefficiencies.     

汽车行业涂装车间排放废水中的镍离子去除方法概论

针对汽车主机厂涂装车间产生的磷化废水,采用化学沉降法去除废水中的镍离子。分别进行了pH值、凝聚剂、絮凝剂投加量以及沉降时间(系统停留时间)对镍离子去除效果影响的试验。结果表明,最佳工艺条件为pH>10.5,沉降时间>4 min,在足够的凝聚剂和适宜的絮凝剂投加量的条件下,废水中镍离子去除率在99.0%以上。将最佳工艺条件应用于工程实际中,废水处理后,出水的镍离子浓度可控制在0.05 mg/L以下,远低于1 mg/L,满足了GB 8978—1996《污水综合排放标准》中镍的排放标准。     

Formation of Denmark Strait overflow water and its hydro-chemical composition

The dense overflow across the Denmark Strait is investigated with hydrographic and hydro-chemical data and the water mass composition of the Denmark Strait Overflow Water (DSOW) is determined by multivariate analysis. Hydrographical properties, the transient tracers CFC-11 and CFC-12, oxygen and nutrients are utilized for the water mass definitions. Distribution and characteristics of water masses north of Denmark Strait are described, the important water masses at the sill and the variability on weekly time-scales are discussed, and the entrainment and mixing of water into the overflow plume in the northern Irminger Basin is calculated. The analysis indicates that water masses both from the Nordic Seas and the Arctic Ocean are important for the formation of DSOW. It is found that water masses transported with the East Greenland Current make up about 75% of the overflow at the sill. The overflow at, and shortly south of, the sill is inhomogeneous with a low-salinity component dominated by Polar Intermediate Water. The high-salinity component of the overflow is mainly of Arctic origin. The water mass composition, and the short-term variability for 7 repeats of sections close to the sill are described, and these illustrate that the overflow is in fact a composite of a number of water masses with different formation and transport histories. This indicate that the overflow is a robust feature, but that it responds to variations in the circulation or atmospheric forcing that influences the formation of intermediate and deep water masses within the Arctic Mediterranean and the North Atlantic. At a section about 400 km south of the sill the overflow is well mixed and modified by entrainment of, mainly, Iceland–Scotland Overflow Water and Labrador Sea Water, together constituting 30% of the overflow plume. The entrainment of Middle Irminger Water dominates shortly downstream of the sill, before the overflow plume reaches too deep but the entrainment seems to be intermittent in time.     

后方通路对淮安盐化工专用线项目的影响分析

淮安盐化工新区专用线接轨于既有新长线袁北站,其后方通路的选择对项目的最小曲线半径、牵引质量、到发线有效长度、闭塞类型等主要技术标准的选取产生影响,从而论证专用线项目后方通路的选择需综合考虑多方面因素来确定。     

温拌沥青混合料制备技术综述

分析了温拌沥青混合料在国内外发展应用状况,按照工作机理,将各种温拌沥青混合料分为三类,详细介绍了各类温拌沥青混合料制备方法与流程,归纳总结各类温拌沥青混合料应用概况。