Intercomparison of Boron Isotope and Concentration Measurements. Part I: Selection, Preparation and Homogeneity Tests of the Intercomparison Materials

In 1999 the Istituto di Geoscienze e Georisorse (IGG), with the support of the International Atomic Energy Agency (IAEA), undertook the collection, preparation and distribution of eight geological materials intended for a blind interlaboratory comparison of measurements of boron isotopic composition and concentration. The materials came from Italian sources and consist of three natural waters (Mediterranean seawater and two groundwaters) and five rocks and minerals (tourmaline, basalt, obsidian, limestone and clay). The solid materials were crushed, milled and mixed, in preparation for distribution. Extensive assays performed at the IGG on these materials demonstrated that their boron isotopic and chemical compositions are homogeneous.
Additional homogeneity tests were carried out on solid material fragments at the GeoForschungsZentrum Potsdam, with the specific objective of investigating the suitability of some of them for the calibration in situ of micro-analytical techniques. Two materials, B4 (tourmaline) and B6 (obsidian), proved to be isotopically homogeneous and may become excellent references for in situ microanalyses of boron isotopes.
The materials described here were used as the basis of a major laboratory intercomparison study and are now available for further distribution from either the IAEA (solid materials) or the IGG (waters).     

水滴冻结实验测量降水物中的冻结核含量

文中介绍了一套新研制的均匀水滴冻结实验装置 ,实验水滴与周围环境同步冷却 ,其温度梯度很小 ,可控制降温速率 ,并能自动记录冻结事件 ,从而提高了实验的精度。用此装置对北京地区 1995年底至 1998年出现的各类降水样品进行了实验 ,由水滴冻结温度谱推算了降水的冻结核浓度 温度谱 ,并对结果进行了分析和讨论     

Verification of the Contribution of Vehicular Traffic to the Total NMVOC Emissions in Germany and the Importance of the NO3 Chemistry in the City Air

In 1997 and 1998 several field campaigns for monitoring non-methane volatile organic compounds (NMVOCs) and nitrogen oxides (NO_x) were carried out in a road traffic tunnel and in the city center of Wuppertal, Germany. C₂–C₁₀ aliphatic and aromatic hydrocarbons were monitored using a compact GC instrument. DOAS White and long path systems were used to measure aromatic hydrocarbons and oxygenated aromatic compounds. A formaldehyde monitor was used to measure formaldehyde. Chemiluminescence NO analysers with NO₂ converter were used for measuring NO and NO₂. The high mixing ratios of the NMVOCs observed in the road traffic tunnel, especially 2.9 ppbv phenol, 1.5ppbv para-cresol and 4.4 ppbv benzaldehyde, in comparison with themeasured background concentration clearly indicate that these compounds were directly emitted from road traffic. Para-Cresol was for the first timeselectively detected as primary pollutant from traffic. From the measured data a NMVOC profile of the tunnel air and the city air, normalised to benzene (ppbC/ppbC), was derived. For most compounds the observed city air NMVOC profile is almost identical with that obtained in the traffic tunnel. Since benzene originates mainly from road traffic emission, the comparison of the normalised emission ratios indicate that the road traffic emissions in Wuppertal have still the largest impact on the city air composition, which is in contrast to the German emission inventory. In both NMVOC profiles, aromatic compounds have remarkably large contributions of more than 40 ppbC%. In addtion, total NMVOC/NO_x ratios from 0.6 up to 3.0ppbC/ppb in the traffic tunnel air and 3.4± 0.5 in the city air of Wuppertal were obtained. From the observed para-cresol/toluene and ortho-cresol/toluene ratios in the city air, evidence was found thatalso during daytime NO₃ radical reactions play an important role in urban air.     

EXPERIMENTAL STUDY ON FLOW AND SEDIMENT MOVEMENT IN CAVITY CIRCULATIONS

1 INTRODUCTION Cavity channels are often found in harbor basins, waterways approaching navigation locks, trench intakes and so on. Because of the expansion of channel section, the main flow is separated from the boundary and forms a circulation flow near the cavity crest. In general, the velocity and turbulent intensity in the circulation flow are lower than that in the main flow, as a result, sediment drawn into the cavity basin is very likely to be deposited there. For instance, the de…     

金在树脂相表面化学发光行为的研究

研究了金在树脂相表面吸附、发光行为、实验方法、仪器装置和仪器工作参数，建立了金的在线分离、富集发光检测新方法。pH值小于1的含金试样，通过装有717阴离子交换树脂脂柱后，金被定量吸队，通以碱性鲁米诺溶液，产生定量化学发光信号，方法的线性范围为0－0.200mg/L，检出限为0.003mg/L。结合金矿石国家二级标准物质分析验证，结果与标准值无显著性差异，RSD（n=10)为2.0%。     

日本Kojima湖的富营养化

日本Kojima湖现在每年的COD平均浓度大约是10mg/L，这是日本环境标准的两倍。COD颗粒的浓度被确定是与叶绿素a的浓度成比例的。另一方面，溶解COD的浓度与叶绿素a的浓度无关。因此，COD颗粒显然是被水藻增长引起的。此外，估计与Kojima湖富营养化相关的内部产物导致的COD的百分比是总COD的20％－30％。     

中国城市人力资本水平与人口集聚对创新产出的影响

基于中国2007—2012年287个地级及以上城市的创新投入要素和专利申请量的面板数据（未含港澳台地区数据）,采用面板固定效应模型和面板分位数回归模型,揭示人力资本水平提升对区域创新产出的影响机制及其区域异质性,以及人口空间集聚对人才创新驱动作用的调节机制。结果表明：① 平均而言,人力资本水平越高的城市,创新产出水平越高,但人口集聚程度与创新产出水平并不存在显著的关联;② 人力资本水平提升对创新的驱动作用存在区域差异,在创新等级越低的城市中其作用效果越强;③ 人口空间集聚强化了人力资本水平对创新的驱动作用,城市规模扩大促进了知识的溢出;④ 人口空间集聚调节作用的显现需要达到一定的创新基础门槛,城市创新等级越高,调节作用越强。因此,各地方政府应当结合当地发展的实际情况,制定适宜的人才培育和人才引进策略,合理引导人才流动。     

北京夏季O3垂直分布与气象因子的相关研究

通过分析2000年7月26日～8月22日北京325 m气象塔的O3浓度梯度观测资料及同期的气象资料,探讨了O3与NOx、风速、风向、温度及相对湿度的关系.通过建立不同风向下O3浓度与NOx、温度、相对湿度及风速的多元回归方程,证实了高浓度的O3是NOx与气象条件综合作用的结果,利用可得到的气象资料及NOx浓度值进行O3污染预报的尝试是可行的.     

淡水湖泊水体中溶解有机氮测定方法的对比

溶解有机氮(Dissolved Organic Nitrogen,DON)是天然水体中氮的重要组成部分,目前研究相对很少．本文对淡水中测定DON的两种常见方法即过硫酸钾湿氧化法(Persulfate Oxidation,PO)和高温催化氧化法(High Temperature Cata- lytic Oxidation,HTCO)进行了对比研究．结果表明:两种方法各有特点,湿氧化法相对较为理想．湿氧化法对不同氮标准化合物的回收率较高,平均为96．0±3．0％以上(杂环氮化合物除外);对湖泊淡水样品,用PO法测定溶解有机氮的相对标准偏差范围为6．2％-12．5％．高温催化氧化法对不同氮标准化合物的回收率较低,平均为68．4±13．6％,需作进一步条件优化．     

福建某河流甲藻水华与污染指标的关系

2009年1-2月份,在福建某河流发现大面积水华,河水呈深褐色经对气温、水温、pH、溶解氧、高锰酸盐指数、氨氮、总氮、总磷以及藻细胞密度、叶绿素a等因子的监测,发现水中有甲藻、隐藻、硅藻、绿藻、蓝藻、裸藻和其它常见种,其中优势种为佩氏拟多甲藻(Peridiniopsis penardii),细胞密度为0.1×10~5-333×10~5cells/L.水体营养盐丰富,总氮浓度为2.50-8.65mg/L、总磷浓度为0.09-1.15mg/L.另外,pH值、溶解氧异常升高,水华反反复复持续一个多月时间.经相关分析,拟多甲藻细胞密度与气温、pH值和总氮相关系数分别为-0.323(P=0.027)、0.327(P=0.025)和0.316(P=0.030),显著相关,偏相关分析表明,拟多甲藻细胞密度与水温相关系数为-0.4894(P=0.008),非常显著负相关.结果显示,pH值和溶解氧升高是甲藻水华产生的表征现象,总氮可能是本次甲藻水华生长的限制因子,而气温和水温的变化既是甲藻水华产生的重要原因,但超过甲藻适宜的生长温度对其也起到一定的抑制作用.由于调查区干旱、少雨、梯级电站过密等因素所导致的水流速过缓,加上足够的营养盐和合适的温度,促使本次拟多甲藻水华的发生.