Inductively coupled plasma-sector field mass spectrometry with a high-efficiency sample introduction system for the determination of Pu isotopes in settling particles at femtogram levels

An analytical method for the determination of plutonium concentration and its isotope ratio (²⁴⁰Pu/²³⁹Pu) for settling particle samples by inductively coupled plasma mass spectrometry (ICP-MS) is presented. The generally used approach for Pu preconcentration by increasing the amount of samples is not applicable because of the small size of settling particle samples available for the analysis for Pu isotopes. Efforts were made to improve the sensitivity of a sector-field ICP-MS (SF-ICP-MS) and reduce the ²³⁸UH⁺ interference for Pu analysis by combining a high-efficiency sample introduction system (APEX-Q). An extremely low detection limit of 0.07 fg Pu was achieved, which allowed the determination of Pu isotope ratio at femtogram levels. The precision and accuracy of ²⁴⁰Pu/²³⁹Pu isotope ratio analysis were carefully examined with a certified Pu isotope standard (NBS-947) and an ocean sediment reference material (IAEA-368). Simple anion-exchange chromatography for the separation and purification of Pu was combined with the APEX-Q/SF-ICP-MS system to determine Pu isotopes in settling particles collected in the East China Sea continental margin. The obtained results supported a previous observation on the lateral transport of Pu containing particles in this continental margin.     

Real-time acoustic classification of sperm whale clicks and shipping impulses from deep-sea observatories

The automated real-time detection and classification of cetacean and anthropogenic sounds from deep-sea observatories can play a key role to study cetaceans in the field, to quantify the impact of anthropogenic sounds or to initiate mitigation measures during potentially harmful human activities. In the area of the NEMO-ONDE deep-sea observatory, sperm whales are often present together with heavy shipping. The spatial coincidence of both sound sources allows for the long term monitoring of their interaction. Some ships produce impulsive sounds and the automated separation of these impulses from sperm whale clicks is not a trivial task. As part of a detection, classification and localisation system for acoustic data from marine observatories, we present four modules performing the automated real-time classification of clicks from sperm whales and impulsive sounds produced by ships. First, two modules detect segments that contain impulsive sounds within a specifiable frequency band and return the impulses’ positions. Then, two modules classify the detected impulses as sperm whale clicks or ship impulses. Finally, at the level of 22 s segments, the classification outputs from individual impulses are combined into a decision on the presence of sperm whale clicks or ship impulses. The modules’ reliability was tested on data from the NEMO-ONDE observatory. Training and testing data were separated by more than 2 months, enabling to assess the consistency of the predictions over the long term. The automated separation between segments of the two classes was high with area under the ROC curve (AUC) values between 0.94 and 0.98.     

核电站温排水分布卫星遥感监测及验证

以大亚湾核电站附近海域为研究区,基于HJ-1B卫星热红外遥感数据IRS4,对核电站温排水空间分布特征进行了识别与验证。首先利用时空插值后的NCEP大气廓线数据,结合近地面气象观测信息对IRS4数据进行大气订正;其次查找表数据建立IRS4宽通道辐亮度与辐射温度转换公式,完成研究区海表温度反演。利用温盐深测量仪,与卫星同步采集了84个离散点的水温,经空间插值获得地面调查海水“体温度”（bulk temperature, BT）的分布,并与海表温度（sea surface temperature, SST）反演结果进行了对比。结果表明,调查区平均BT比平均SST高0.47 ℃。在远离热排放口区域,SST高于BT,两者差异在1.0 ℃以内;在靠近热排放口区域,SST低于BT,并且越接近排放口两者之间差距越大。遥感与地面调查两种手段获得的温升分布基本一致,总温升区域面积相近。遥感手段获得的温升等级较少（小于4级）,地面调查获得温升等级较多（大于5级）;后者高温升等级（2级以上）区域面积较大,但对于1级温升区面积而言,两种手段差异较小。上午10时左右海表BT与SST差异较小,“肤-体”温差效应可以忽略,在IRS4业务化SST应用中,这一时段的卫星遥感可以作为核电站温排水分布监测的常规手段。     

A Numerical Approach to Marine Circulation Using Free Surface or Rigid-lid Modeling: Application in the Bay of Calvi

When establishing a model of fluid flow in marine modeling, a key issue is the choice between a rigid-lid approach or a free surface level model. This is not a trivial issue as it plays an important role, not only in the choice of the numerical techniques, but also in the qualitative and quantitative aspects of the numerical results. Most software use either free surface or rigid-lid hypotheses, but comparing their results is difficult, since the numerical tools used are in general, extremely different. In this work, some numerical investigations comparing rigid-lid and free surface models are presented. A numerical method using Galerkin's method, but with a new basis, is applied to solve the rigid-lid equations in a realistic domain with varying bottom. A numerical method, similar to the one already used for free surface equations (the same truncating method and precision level) is applied, where the main differences between the simulation results depend only on the model employed. In addition, a comparative simulation between rigid-lid and free surface models to study marine circulation in the bay of Calvi (Corsica) is presented, and numerical results in the non-stratified case only (fluid with constant density) are described, as no further difficulties appear in the stratified case.     

FI-KR-FAAS空气混合吸附二次气体分隔洗脱法测定海洋生物样中的痕量铅

建立了流动注射（flow injection, FI）空气混合吸附预富集编结反应器（knotted reactor, KR）二次气体分隔洗脱法与火焰原子吸收光谱法（flame atomic absorption spectrum, FAAS）联用测定海洋生物样中的痕量铅。在预富集步骤,空气、络合剂和铅溶液在线混合,空气的引入,大大提高了铅的螯合物在KR内壁的吸附效果。在洗脱前,通入一段空气流,在洗脱过程中,即在非完全洗脱时,加入一段空气流,两段空气流的引入,大大降低了被分析物在洗脱液中的分散,提高了信号响应值,从而提高了浓集系数（enhancement factor, EF）。将空气混合吸附预富集与二次气体分隔洗脱法联用,使得KR吸附富集效果和洗脱效果达到了更高的水平。和微柱的低寿命、高反压相比,KR反压小,耐酸耐碱,寿命几乎无限长,对蠕动泵的要求很低,不易造成溶液渗漏等问题。在洗脱过程进行到第5秒时输入1 s空气流作为间隔,而不是等整个洗脱过程完成以后再输入空气流,此方法的优点是：洗脱完全,而且大大降低了被分析物在洗脱过程中的分散,吸收信号值大大增加。如果单纯地把洗脱时间降到5 s,那么洗脱会非常不完全,也就是没有洗脱干净,在管路中还会残存大量的被分析物,残存的被分析物被带入下一个样品分析中,会对整个实验造成很大的误差,所有的实验数据都将不准,失去数据利用价值。所以完全的洗脱是非常必要的,必须保证一定的洗脱时间。由于随着洗脱过程的进行,洗脱下来的被分析物呈逐渐减小的趋势,在以往洗脱方法中,等到整个洗脱过程全部进行完以后,被分析物在洗脱液中的分散已经相当严重了,导致所得到吸收信号值大大减小。在洗脱过程中插入空气流,即在非完全洗脱时插入空气流,降低了被分析物在洗脱过程中的分散,同时保证了洗脱的完全,大大提高了吸收信号峰值。优化了络合剂种类、浓度和酸度,样品富集时间和流速,空气混合吸附时的空气流速和时间,洗脱前第一次通气时间,预洗脱时间,洗脱过程中第二次通气时间等实验参数。在最佳实验条件下,铅在0.005～0.6 mg·L-1浓度范围内呈现良好的线性关系,铅的检出限（3σ）为2.2 μg·L-1。将新方法与直接火焰原子吸收法、传统的FI-KR空气混合吸附预富集普通洗脱法进行了比较,结果显示本方法的浓集系数更高。将该方法应用于海洋生物样中痕量铅的测定,测得鳝鱼、对虾、虾姑、鲟鱼、舌鳎和贻贝标准中的铅含量为0.34~1.92 μg·g-1;加标量为1.0 μg·g-1时,加标回收率为93.5%~96.4%;相对标准偏差为0.52%~2.94%。用FI-KR-FAAS空气混合吸附预富集,二次气体分隔洗脱法测定海洋生物样中的痕量铅,具有富集效果好,准确度高,精密度好,浓集系数高等优点,分析结果令人满意。     

银/金刚石微粉复合材料对硝酸盐红外吸收特性的影响

中国海洋环境的污染日趋严重,其中大部分是由无机氮和磷酸盐导致。有效快速的监测海洋营养盐,尤其是硝酸盐,已成为一个显要的问题。传统的检测方法主要是利用化学分析法,更适合实验室测试之用。红外吸收光谱对海洋营养盐的实时监测具有重要意义,能够弥补传统方法的不足,并具有快速、同步监测多种营养盐等优点。但海水中的营养盐浓度极低,使得红外光谱检测极限难以满足要求。纳米材料能产生表面增强红外吸收(SEIRA)效应,利用此效应,使红外光谱检测海洋营养盐技术成为可能,优点得以发挥。纳米银(Ag)具有显著的表面等离子体共振效应,可以帮助实现SEIRA。金刚石具有过强的抗腐蚀性和其他特殊的性能,如高硬度和高光透射率,是理想的红外窗口材料。具体来说,利用热分解硝酸银的方法在硅基底(Si substrate)上制备了银/金刚石微粉(Ag/DP)复合材料,研究了银与金刚石微粉的不同比例对NaNO₃(一种主要海洋营养盐)的水溶液红外吸收的影响。结果表明,Ag/DP复合材料使NO-₃的两种反对称伸缩振动ν_high和ν_low的红外吸收有较大幅度提高;银与金刚石微粉比例为2∶1时,硝酸钠水溶液的红外吸收增强效果最佳。该实验结果将对海洋营养盐进行实时、长期、连续的检测提供重要信息,为海洋灾害预防、海洋环境污染治理等海洋领域提供有力的数据支持。     

New Sterol Derivatives from the Marine Sponge Xestospongia sp.

Chemical examination of a marine sponge Xestospongia sp. resulted in the isolation of 20 sterol derivatives ( 1 – 20 ), including eight new sterols namely aragusterols J – L ( 1 – 3 ), (5α,7α,12β,22E)‐7,12,18‐trihydroxystigmast‐22‐en‐3‐one ( 4 ), (5α,7α,12β,24R)‐ and (5α,7α,12β,24S)‐7,12,20‐trihydroxystigmastan‐3‐one ( 5 / 6 ), and (5α,7α,12β,22E,24R)‐ and (5α,7α,12β,22E,24S)‐7,12,20‐trihydroxyergost‐22‐en‐3‐one ( 7 / 8 ). The structures of new compounds were determined through extensive spectroscopic analyses and chemical conversion. The sterol diversity was mainly characterized by the presence of a cyclopropane unit at side chain, while compound 4 with 18‐hydroxymethyl group was found in stigmasterol family for the first time. Cytotoxic test revealed the inhibitory effects of compounds 1 , 4 , and 17 against human leukemia cell line K562 with IC₅₀ values of 18.3, 24.1, and 34.3 μm , respectively.     

ICP-AES法测定6种海产品中的营养元素及营养功能的探讨

本文用ICP－AES法测定了6种海产品中的6种营养元素,讨论了与实验有关的相关因素。该方法回收率为96％－103％,相对标准偏差＜4％,结果令人满意。     

海洋用钢在含硫酸盐还原菌的海泥中的应变电化学响应

海洋用钢在海底泥土区常承受具大的应力 ,而应力将对海洋用钢的腐蚀破坏行为产生影响 .本文选用一种常用的海洋用钢 ,采集含有硫酸盐还原菌 (SRB)的天然海泥 ,研究试样在海泥中的腐蚀行为 ,以及试样在有裂纹和无裂纹存在时的电流响应特征     

海生物附著对钢板管椿腐蚀之影响

为了解海生物对钢板管椿腐蚀之影响 ,将SS4 1金属试片浸渍于高雄港 #1 4码头水深 3m处及实验室人造海水中 .试验期间 ,以DC直流动电位极化曲线扫描与AC交流电阻抗分析现场量测各试片的瞬间腐蚀速率 .结果发现 :宏观地看 ,海生物在金属 (或锈层 )表面的附著可以减缓金属腐蚀 ,但从微观 (micro)的观点推论 ,海生物在金属表面的附著亦可以造成氧差或浓度差异电池 ,促成局部腐蚀 .此外 ,等效电路的模拟 ,有助于了解海生物附著对金属腐蚀的影响 ,即随浸渍时间的延长 ,金属表面因锈层增厚且趋于致密 ,以致锈层电阻增加 ;又因海生物种类不同 ,含水量不同 ,海生物电阻可能会有极大的差异