物理法采油中振动频率与地质条件的关系研究

物理法采油技术研究大都偏重于现场试验,对其机理及规律性的认识仍停留在感性认识与定性解释的水平上,其工艺设计仅凭经验,导致了现场应用在一定程度上的盲目性,影响应用效果。为此,通过模拟试验装置模拟现场工况,分析测试结果后知,不同频率的振动对渗透率的影响不同,在模拟的频率段内,50 Hz的处理效果最好,20 Hz的处理效果最差;低频振动解堵的适应范围较宽,中高渗透层因颗粒堵塞较严重的井,解堵效果理想,而且解堵半径在30cm;各种频率的有效解堵时间25 min,考虑实际工况较复杂,可以适当延长处理时间。     

Multiplex ligation-dependent probe amplification (MLPA) for simultaneous detection of DNA from sunflower,poppy, flaxseed,sesame and soy allergenic ingredients in commercial food products

This work describes a multiplex ligation-dependent probe amplification (MLPA) technique for the simultaneous detection of five food allergens: sunflower, poppy, flaxseed, sesame and soy. Species-specific MLPA half-probes were designed to detect the DNA from the targeted species. Ligated probes were amplified by polymerase chain reaction (PCR) and amplicons were detected using capillary electrophoresis. The specificity of the MLPA system was assessed against DNA from more than 50 plant and animal species. The limit of detection (LOD) of the assay was determined to be 10 mg kg⁻¹in a model cookie experimentally spiked with different concentrations of the target species. The applicability of the MLPA was demonstrated through the analysis of 56 different commercial products (breads, pastries, cereals, chocolates, drinks, etc.), evidencing the presence of one or more undeclared allergenic ingredients in some of the tested samples. Real-time PCR assays were also performed to confirm and complement MLPA results. The MLPA technique has proved as a qualified screening tool for determining the presence of low amounts of sunflower, poppy, flaxseed, sesame and soy in processed foods.     

Inhibition of food poisoning and pathogenic bacteria by Lactobacillus plantarum strain 2.9 isolated from ben saalga, both in a culture medium and in food

The bacteriocinogenic strain Lactobacillus plantarum 2.9 isolated from the traditional pearl millet-based African fermented food ben saalga was tested for inhibition of food poisoning and pathogenic bacteria in MRS broth and in a malted millet flour slurry. In MRS broth, strain 2.9 completely eliminated Bacillus cereus, Escherichia coli O157:H7 and Salmonella enterica cells within 48 h incubation at 22–30 °C. A much lower inhibition was observed at 15 °C. The inhibitory effect of strain 2.9 on the above-mentioned target bacteria was corroborated in the malted millet flour slurry, reducing viable cell counts below detection levels after 8 h storage for B. cereus or after 24 h for S. enterica and 48 h for E. coli. An Enterobacter aerogenes strain was only moderately inhibited in the slurry. Results from the present study suggest that strain 2.9 could be used as starter culture to improve the microbiological safety of fermented ben saalga.     

垦71地区转换波油气检测技术研究

利用常规纵波地震检测油气多解性较大,而转换波地震资料中随方位角变化的横波分裂现象与地层孔隙压力变化密切相关。对垦71地区转换横波分裂产生的时移、振幅特性及时差谱与油水关系的分析表明,利用多波多分量地震资料能提高油气藏预测的可靠性。     

Rapid analysis of melamine residue in milk,milk products,bakery goods and flour by ultra-performance liquid chromatography/tandem mass spectrometry: From food crisis to accreditation

A simple and rapid ultra-performance liquid chromatographic (UPLC) method with tandem mass spectrometry has been developed and validated for the determination of melamine in milk, milk products, bakery goods, and flour. The method comprises a simple extraction step with a solution of acetonitrile–water, ultrasound treatment and a liquid–liquid extraction with dichloromethane for fat removal. The purified extract is further diluted before injection on a ACQUITY BEH Hilic, with a total run of 2 min. Quantification of the results was performed with isotopic dilution (¹³C₃-labelled melamine). No matrix effect was observed. Consequently solvent-based standards could be used for the calibration curve witch ranges from 0.5 mg/kg to 40 mg/kg. The calibration function was linear with a determination coefficient of >0.999 (r²). The limit of detection and the limit of quantification were respectively 0.2 and 0.5 mg/kg. Repeatability and within-lab reproducibility were <6% RSD. Average apparent recovery of melamine ranged from 97% to 99%. Accuracy of the method has been successfully tested by participating in two proficiency tests. The method is easily performed with confident quantification and provides a good alternative to solid phase extraction as well as to time-consuming derivatization prior to gas chromatography.     

根据原油成熟度参数确定排烃门限的新方法——基于渤海海域莱州湾凹陷KL6D构造区烃源岩评价与油源对比

针对渤海海域莱州湾凹陷钻井少、有机地球化学资料不够丰富的特点,基于KL6D构造区烃源岩评价与油源对比,提出了一种根据原油甾烷异构化成熟度参数C29ααα20S/(20S+20R)确定排烃门限的新方法。根据KL6D构造区烃源岩和已发现原油的C29ααα20S/(20S+20R)成熟度参数与深度拟合的线性公式,确定该构造及围区的排烃门限深度为3 320 m,该深度以下烃源岩对研究区油气成藏有显著贡献。本文方法确定的排烃门限能直观地刻画研究区有效烃源岩,特别适用于少井和浅井地区。     

巯基棉富集—火焰原子吸收光谱法测定催化剂及其三氧化二铝载体中的铜、镉、铅

取5克以上试样溶解后用1—2倍摩尔的草酸钾掩蔽铝,在4.5—6.0pH 值下 Cu~(2+)、Pb~(2+)、Cd~(2+)能被巯基棉定量吸附并与基体元素 Al~(3+)分离。然后用2mol/l 盐酸洗脱,在接收液中同时测定铜、镉、铅三种元素。