三亚电厂工程影响潮流场数值模拟

运用嵌套方法对拟建三亚电厂工程海域潮流场进行了数值模拟，预测了电厂码头工程对潮流场的影响。模拟结果表明，嵌套方法的应用更精确地模拟了海岸线的几何形状，提高了工程海域潮流场的精度，清晰地再现了流场的微细结构。     

Phytoplankton in the Weddell Sea,Antarctica: composition,abundance and distribution in water-column assemblages of the marginal ice-edge zone during austral autumn

At the compacted, north-south line of the ice edge, phytoplankton were sampled during early austral autumn of 1986 in the northwestern Weddell Sea. Cells from discrete water bottle samples from 12 stations on two east-west transects were counted to gain quantitative information on the composition, abundance, distribution, and condition of the phytoplankton in water-column assemblages. Over 70 species were found. The highest numbers of total cells (integrated through the top 150 m) were found in open water, well-separated from and to the east of the ice edge on the southern transect, with 6.01×10¹⁰ cells m^-2. The relative abundance of diatoms was low at ice-convered stations (< 35% of the total phytoplankton in preserved samples) and high at open-water stations (> 80%); however, the relative abundance of the prymnesiophyte Phaeocystis sp. was high at ice-covered stations (> 60%) and low at open-water stations (< 16%), with lower absolute abundances than during a previous austral-spring phytoplankton increase. In the open ocean, the dominants were the pennate diatoms Fragilariopsis cylindrus, Pseudonitzschia prolongatoides, F. curta, and a small form of the centric diatom Chaetoceros dichaeta in chains. Although the three pennate diatoms were frequently dominant in number, they represented less biomass than C. dichaeta in open waters. Mean phytoplankton abundance was low (0.2×10⁶ cells l^-1) but, overall, the diatom cell density (0.14×10⁶ cells l^-1) was similar to that found previously during a northward transect from ice-covered to ice-free water at the Weddell-Scotia Sea ice edge (spring 1983). The phytoplankton spatial patterns in the two autumn transects differed, with the more southerly transect exhibiting a higher abundance of diatoms and dinoflagellates. The ratio of full to empty diatoms was higher on the southern transect, indicating a healthy population, while lower ratios of full/empty frustules on the northern transect suggested a generally declining population. However, Phaeocystis sp. was more abundant on the northern transect.     

PTA污水处理装置存在问题及对策

针对洛阳石化PTA污水处理装置存在的主要问题，通过分析，提出了相应对策，优化了生产操作，提高了装置的处理水平，保证了污水的达标排放。     

Monitoring of reduced sulfur compounds in the atmosphere of Gosan, Jeju Island during the Spring of 2001

The atmospheric concentrations of dimethylsulfide (DMS) and carbon disulfide (CS2) were measured concurrently with relevant environmental parameters at Gosan, Jeju Island, Korea during 5-26 April 2001. The mean concentrations for these two compounds were 18.7+/-17.9 and 6.4+/-9.9 pptv, respectively. Results of our analysis indicated that relative temporal variations between DMS and CS2 can be best described by dividing the whole data set into three different periods which reflect the variable transport patterns of air masses into the study area. (Periods I, II, and III denote: 5-10, 10-18, and 19-26 April.) The environmental conditions during those three periods varied greatly. The effects of continental and/or oceanic processes were evident for certain periods, yielding diverse relationships between DMS and CS2 in both absolute and relative terms. Most observed variations were best explained in terms of an interplay between source/sink processes and air mass transport patterns. The sea-to-air flux of DMS, when estimated using our measurement data during this study period, was approximately 4 micromole m(-2)d(-1).     

Transport characteristics of gas phase ozone in unsaturated porous media for in-situ chemical oxidation

Encapsulation technology is being investigated as a method for controlling pH in situ at contaminated groundwater sites where pH may limit remediation of organic contaminants. This study examined the effectiveness of using KH2PO4 buffer encapsulated in a pH-sensitive coating to neutralize pH in laboratory sand columns (1.5-1) under a simulated groundwater flow rate and characterized the pattern of capsule release in the flow-through system. Denitrification was used in the columns to increase the pH of the pore water. Each of three columns was equipped with three miniature mesh wells to allow contact of the buffer with column pore water, but capsules (15 g) were inserted into only one column (amended). The two other columns served as amendment (no buffer) and abiotic (no denitrification) controls. Oxidation-reduction potential, dissolved organic and inorganic carbon, NH4+, NO3- +NO2-, PO(4)3-, and pH were measured in the influent, two side ports, and effluent of the columns over time. Near complete conversion of 80 mg N/1 of nitrate and 152 mg/l of ethanol per day resulted in a mean pH increase from 6.2 to 8.2 in the amendment control column. The amended column maintained the target pH of 7.0 +/- 0.2 for 4 weeks until the capsules began to be depleted, after which time the pH slowly started to increase. The capsules exhibited pulses of buffer release, and were effectively dissolved after 7.5 weeks of operation. Base-neutralizing capacity contributed by the encapsulated buffer over the entire study period, calculated as cation equivalents, was 120 mM compared to 8 mM without buffer. This study demonstrates the potential for this technology to mediate pH changes and provides the framework for future studies in the laboratory and in the field, in which pH is controlled in order to enhance organic contaminant remediation by pH-sensitive systems.     

Atmospheric concentrations of PM2.5 trace elements in the Seoul urban area of South Korea

Fine particles (PM2.5) were collected during all four seasons, from April 2001 to February 2002, in Seoul, South Korea, using an annular denuder system. Elemental compositions of ambient PM2.5 were analyzed using the proton-induced X-ray emission method. The greatest contributors (> or = 2%) to the PM2.5 mass were sulfur (S), silicon (Si), chlorine (Cl), aluminum (Al), and iron (Fe) in the spring; S in the summer; and S and Cl in the fall. S, Cl, and Si were the major elements in the winter. S was the most abundant species among the elements, ranging from 5.3 to 7.9%, followed by Si and Cl. From analysis of variance, PM2.5 mass, Al, Si, potassium, calcium, and Fe showed significant seasonal differences during the four seasons (p < 0.001). Enrichment factor (EF) analysis was carried out to identify the sources affecting the aerosol in the Seoul area. On the basis of the mean EF values, elemental S, copper, zinc, and lead may be emitted from anthropogenic sources (EF > 50). Elemental Al, Si, titanium, and Fe may be emitted from crustal sources (EF < 3). Additionally, a correlation analysis was carried out for source identification. The results of the correlation analysis were confirmed by the results of the EF analysis.     

Volatile organic compounds in some urban locations in United States

Volatile organic compounds (VOCs) have been determined to be human risk factors in urban environments, as well as primary contributors to the formation of photochemical oxidants. Ambient air quality measurements of 54 VOCs including hydrocarbons, halogenated hydrocarbons and carbonyls were conducted in or near 13 urban locations in the United States during September 1996 to August 1997. Air samples were collected and analyzed in accordance with US Environmental Protection Agency-approved methods. The target compounds most commonly found were benzene, toluene, xylene and ethylbenzene. These aromatic compounds were highly correlated and proportionally related in a manner suggesting that the primary contributors were mobile sources in all the urban locations studied. Concentrations of total hydrocarbons ranged between 1.39 and 11.93 parts per billion, by volume (ppbv). Ambient air levels of halogenated hydrocarbons appeared to exhibit unique spatial variations, and no single factor seemed to explain trends for this group of compounds. The highest halogenated hydrocarbon concentrations ranged from 0.24 ppbv for methylene chloride to 1.22 ppbv for chloromethane. At participating urban locations for the year of data considered, levels of carbonyls were higher than the level of the other organic compound groups, suggesting that emissions from motor vehicles and photochemical reactions strongly influence ambient air concentrations of carbonyls. Of the most prevalent carbonyls, formaldehyde and acetaldehyde were the dominant compounds, ranging from 1.5-7.4 ppbv for formaldehyde, to 0.8-2.7 ppbv for acetaldehyde.     

翅片式防爆柴油机排气冷却器烟气侧数值分析

建立了翅片式防爆柴油机排气冷却器的计算模型,通过FLUENT软件对其烟气侧进行了仿真分析,探讨了防爆柴油机排气冷却器烟气内部的流场及温度场分布规律,仿真结果与热平衡试验结果基本一致,表明建立的数值分析模型准确,为翅片式排气冷却器的设计优化提供了理论指导。     

Risk of motor vehicle accident death among 1.3 million veterans of the Iraq and Afghanistan wars

Objective: We conducted a cohort study of recent wartime veterans to determine the postservice mortality risk due to motor vehicle accidents (MVAs).

Methods: Veterans were identified from the Defense Manpower Data Center records. Deployment to te Iraq or Afghanistan war zone was determined from the Contingency Tracking System. Vital status of 317,581 deployed and 964,493 nondeployed veterans was followed from their discharge dates between 2001 to 2007 until earlier of date of death or December 31, 2009. Underlying causes of death were obtained from the National Death Index Plus.

Results: Based on 9,353 deaths (deployed, 1,650; nondeployed, 7,703), of which 779 were MVA deaths as drivers (166; 613), both cohorts had 25 to 24% lower mortality risk from all causes but had 44 to 45% higher risk of MVA deaths relative to the U.S. general population. The higher MVA mortality risk was not associated with deployment to the war zone. After controlling for age, sex, race, marital status, branch of service, and rank, the risk for deployed veterans was comparable to that of nondeployed veterans (hazard ratio = 0.91; 95% confidence interval, 0.77–1.09).

Conclusions: Veterans exhibit significantly higher risk of MVA deaths compared to the U.S. general population. However, deployment to the Iraq or Afghanistan war was not associated with the excess risk.     

可持续发展的理论与宏观调控模式

从可持续发展观和可持续发展战略出发,分析了传统发展观和发展模式的特点及其主要弊端;进而根据有关国际性文件中的可持续发展概念,给出了中国人易于理解的描述及其基本内涵,强调了人与自然和谐、发展与资源环境相协调是可持续发展的核心,并结合实例阐明了协同学理论是可持续发展的基本理论依据;在分析发展与资源环境相协调的基础条件之后,重点论述了它们之间的协调机制,提出了可持续发展的宏观调控模式。