Urinary mercury in people living near point sources of mercury emissions

As part of the European Mercury Emissions from Chlor Alkali Plants (EMECAP) project, we tested the hypothesis that contamination of ambient air with mercury around chlor alkali plants using mercury cells would increase the internal dose of mercury in people living close to the plants. Mercury in urine (U-Hg) was determined in 225 individuals living near a Swedish or an Italian chlor alkali plant, and in 256 age- and sex-matched individuals from two reference areas. Other factors possibly affecting mercury exposure were examined. Emissions and concentrations of total gaseous mercury (TGM) around the plants were measured and modeled. No increase in U-Hg could be demonstrated in the populations living close to the plants. This was the case also when the comparison was restricted to subjects with no dental amalgam and low fish consumption. The emissions of mercury to air doubled the background level, but contributed only about 2 ng/m(3) to long-term averages in the residential areas. The median U-Hg levels in subjects with dental amalgam were 1.2 microg/g creatinine (micro/gC) in Italy and 0.6 microg/gC in Sweden. In individuals without dental amalgam, the medians were 0.9 microg/gC and 0.2 microg/gC, respectively. The number of amalgam fillings, as well as chewing, fish consumption, and female sex were associated with higher U-Hg. The difference between the countries is probably due to higher fish consumption in Italy, demethylated methyl mercury (MeHg) being partly excreted in urine. Post hoc power calculations showed that if the background mercury exposure is low it may be possible to demonstrate an increase in U-Hg of as little as about 10 ng/m(3) as a contribution to ambient mercury from a point source.     

沉积背景控制下的储层预测方法——以大牛地气田TGM地区的应用为例

TGM地区是大牛地气田天然气产能建设的重要区块,但该区天然气储层层系多、厚度薄,横向非均质性强,加之地震资料分辨率低,导致精确储层预测困难。为减小TGM地区储层预测的多解性,最大限度地提高储层预测的精度,在深入分析TGM地区储层发育地质特征的基础上,提出了沉积背景控制下的储层预测思路：将TGM地区储层预测作为一个系统工程,首先从储层的沉积背景出发圈定储层发育有利区块;然后针对有利区的地质情况和地震资料特征,选取针对性的储层预测方法和技术,对储层进行精细刻画。针对TGM地区太原组、山西组和下石盒子组储层预测的结果与钻井的符合率在90%以上。     

丝锥用Nb微合金化TGM2A-S高速钢的开发

TGM2A-S钢(/%:0.85C、0.27Si、0.24Mn、0.026P、0.007S、3.98Cr、4.76Mo、6.09W、1.83V、0.12Nb、0.03RE)是在高速钢TGM2A的基础上添加微量铌和稀土开发的新型丝锥用高速钢。TGM2A-S钢的生产工艺流程为25 t EAF-30 t LF-VD(微合金化)-铸锭(700 kg)二火锻造(85 mm方)-连轧(Φ8 mm)-冷拉(Φ6.6 mm)-加工丝锥(M6)。结果表明,原工艺:3 t中频感应炉-ESR (280 kg锭)-二火锻造(85 mm方)-连轧(Φ8 mm)-冷拉(Φ6.6 mm)-加工丝锥(M6)生产的TGM2A钢中的O和N含量分别为35.4×10^-6和123.6×10^-6,而改进工艺生产的TGM2A-S钢的O和N含量分别为15.7×10^-6和87.7×10^-6。TGM2A-S钢的丝锥切削寿命较电渣工艺生产的TGM2A钢提高20%; TGM2A-S钢的淬火晶粒为10.5级,电渣工艺生产的TGM2A钢的晶粒度为10级。     

Urinary mercury in adults in Poland living near a chloralkali plant

We conducted a study within the framework of the interdisciplinary European Mercury Emission from Chloralkali Plants (EMECAP) project to assess exposure to mercury (Hg) and the contribution of Hg emissions from a mercury cell chloralkali plant to urinary mercury (U-Hg) in adults living near the plant. We collected data from questionnaires and first morning urine samples from 75 subjects living near the Tarnow plant in Poland and 100 subjects living in a reference area. Median U-Hg was 0.32 mug/g creatinine (microg/gC) and 0.20 microg/gC, respectively. The median U-Hg was also higher in the amalgam-free subjects living near the plant (0.26 microg/gC) than in the reference group (0.18 microg/gC), but no such association was found in a multivariate analysis. There was a statistically significant positive association between U-Hg and number of teeth with amalgams, a negative association with age and a tendency towards higher U-Hg in female subjects. In the amalgam-free subjects there were statistically significant effects of female sex and fish consumption, and a negative association with age. The additional long-term average air Hg concentration from the plant, based on EMECAP environmental measurements and modelling, was estimated to be 1-3.5 ng/m(3) for the residential study area and should have a very small effect on U-Hg. The other Hg emission sources such as coal combustion facilities located nearby should be taken into account in assessing the overall impact of air Hg on U-Hg in this area.     

宝石级金刚石单晶生长机制的研究---低速生长条件下的晶体生长特性

高温高压温差法生长优质宝石级金刚石单晶要求严格控制晶体的生长速度,因为晶体生长速度过快会导致熔体金属来不及扩散从而在晶体中产生包裹体,影响晶体的质量。本文考察了低速生长条件下宝石级金刚石单晶的生长情况,结果发现,在以{100}面作为晶种的生长面的情况下,无论合成温度高低,低速生长(本文中为0．40mg/h)出的晶体中均不存在金属包裹体,这与日本住友公司早期的结果有所不同。     

FeNi-C-FeS体系金刚石中氮含量的研究

利用高温高压温度梯度法,在FeNi-C-FeS体系中进行了宝石级金刚石大单晶的合成研究,重点考察了FeS含量对金刚石中氮含量的影响。结果发现体系中随着掺杂FeS含量的增加,晶体品质会遭到一定程度的破坏,尤其是{100}生长区域。对晶体中氮含量而言,当掺杂FeS的量由0增加至1.25%时,{111}生长区域的氮含量与纯FeNi-C体系相比几乎没有发生变化,而{100}生长区域的氮含量却发生较大变化,远远低于纯FeNi-C体系中{100}生长区域的氮含量。这说明掺杂FeS更易对晶体的{100}生长区域产生影响,或者说S元素更容易进入{100}生长区域,这样S原子与N原子之间产生竞争,使氮原子进入金刚石的几率减少,导致{100}生长区域的氮含量急剧下降。     

An analytical model for estimating deformation in laser forming

Laser forming of metal sheets offers the advantages of requiring no external forces and thus reduces cost and increases flexibility. This paper presents an analytical model to estimate the angle bent during the laser forming of a sheet. Plastic deformation is considered during both heating and cooling and is calculated based on a history-dependent incremental stress–strain relationship. On the basis of the proposed model with known temperature distributions, the bending angle induced by laser can be calculated. Comparison of the present model with experiment data is provided to demonstrate the accuracy of the present model under both TGM and BM.     

基于TGM-ARMA模型的地铁隧道结构沉降预测分析

地铁隧道结构沉降主要受土层状况、地下水位、轨道荷载及周边环境等诸多因素影响,机理复杂,随机性强,而且随时间不断变化,难以用固定的数学模型表示,是一个非平稳的过程。据此,结合以灰色系统理论为基础的TGM(1,1)模型和以时间序列为基础的ARMA(n,m)模型各自的特点,建立了时变参数灰序模型TGM(1,1)-ARMA(n,m),并对地铁隧道主体结构沉降进行了分析与预报,结果表明时变参数灰序模型预测精度较高,且适用于中长期预测。因此,该组合模型在地铁隧道结构沉降预测分析中有较强的适用性,具有一定的应用价值。     

红外制导技术发展综述（Ⅰ）

介绍并评述了海湾战争使用的精确制导弹药，对三代红外制导、两代红外成像制导、三代反坦克导弹，以及末敏弹和末制导炮弹的发展，作比较详细和系统的综述；最后介绍采用复合制导体制的末制导炮弹。     

Total gaseous mercury (TGM) concentration over Lake Superior and Lake Michigan

Mercury-contaminated fish are a serious problem in the Great Lakes basin, because mercury is a potent neurotoxin that poses a danger to both humans and wildlife. Lake Superior lake trout and walleye have the highest mercury concentrations of the five Great Lakes. Because the atmosphere is the major source of mercury to the Great Lakes, information on the over-water mercury concentration is essential to model the mercury biogeochemical cycle. For the first time in the peer-reviewed literature, this paper presents total gaseous mercury (TGM) measurements made over Lake Superior and Lake Michigan. The Lake Superior aircraft measurements were made at an altitude of 300 m, and the Lake Michigan aircraft measurements at a variable altitude of 30–300 m. The over-water Lake Superior TGM of 1.02 ± 0.34 ng/m³ is much lower than the TGM from nine stations in the Canadian Atmospheric Mercury Measurement Network (CAMNet) and six stations in the Atmospheric Mercury Network (AMNet). The land-based TGM concentrations average range from 1.25 to 1.75 ng/m³ which are in good agreement with current global average values of 1.3–1.6 ng/m³. The over-water Lake Michigan TGM is 1.65 ± 0.61 ng/m³. We also present Lake Superior over-water measurements of volatile organic compounds (VOC), ozone (O₃), nitrogen oxide (NO_y), and particulate matter. Elemental carbon (EC) is a tracer for mercury because mercury is released during the combustion of coal. EC is significantly correlated with TGM over both Lake Superior and Lake Michigan. TGM over Lake Michigan is also significantly correlated with organic carbon, sulfate, nitrate and ammonium.