基于主成分分析法的大坝风险后果综合评价模型

 大坝风险后果综合评价涉及众多评价因子,各因子间存在一定的相关性。将主成分分析理论应用于大坝风险后果的综合评价,以江西5座水库为例,将数据标准化,根据相关系数矩阵,以综合因子的贡献率确定主成分和权重,计算出主成分值以及综合分值,结合评价标准最终确定大坝风险后果等级并对其进行排序。结果表明：若发生溃坝事件,5座水库大坝后果均十分严重,属特别重大事故,评价结果客观合理。研究表明,主成分分析法能够较客观地反映大坝风险程度,具有方法简便、推理过程严密等特点,为大坝风险后果综合评价提供一条新途径。     

脱硫剂反应活性综合评价体系的研究

该文将流化床燃烧脱硫剂的微观结构与反应性能有机地结合在一起，选取了化学成分和微观孔结构特性两类参数作为预测和评估脱硫剂反应活性的基本指标，采用主成分分析方法对5种钙基脱硫剂样本建立了综合评价标准与体系，为评价脱剂的反应性能提供统指标，同时为优化选取高效脱硫剂提供理论基础。     

渤海湾盆地沾化凹陷沙河街组富有机质页岩孔隙分类及孔径定量表征

页岩微观孔隙特征分析和孔径定量表征是页岩油气储层评价和开发的关键。通过岩心观察、薄片鉴定、X-衍射、扫描电镜、氮气吸附等实验手段,分析了渤海湾盆地沾化凹陷富有机质页岩的矿物组成和微观孔隙类型,并对微观孔径进行了定量表征。结果表明：沙河街组页岩具有碳酸盐矿物含量高、粘土矿物含量较低的特征。根据发育位置、成因及产状,将储集空间分为孔隙与裂缝两大类,并制定了孔隙和裂缝的尺度评价标准。孔隙包括矿物基质孔隙和有机质孔隙;裂缝包括构造、层间、超压破裂、成岩和有机质收缩裂缝。氮气吸附等温曲线主要存在3种类型,分别反映了样品中微孔、中孔及宏孔的分布差异。通常氮气吸附实验能更好地表征中孔的发育特征,而扫描电镜所测孔隙更好地表征了宏孔的发育。需要进一步采用二氧化碳吸附、纳米CT及压汞实验定量表征页岩的微孔和宏孔的大小及分布。     

Authentication of Iberian dry-cured ham: New approaches by polymorphic fingerprint and ultrahigh resolution mass spectrometry

Foods with high added value, such as Iberian dry-cured products, are susceptible to fraud. Many attempts have been made to differentiate the commercial/quality categories of Iberian dry-cured hams by analytical determinations. However, as discrimination by such means is not fully reliable, legislation to prevent fraudulent practice is based on administrative controls and certification. Here, new analytical approaches based on ultrahigh resolution mass spectrometry (UHRMS) and crystallographic techniques applied to the lipid fraction, in combination with chemometrics, are studied. The results of the triacylglycerol profile determined by UHRMS and the fingerprint provided by the thermograms obtained by differential scanning calorimetry offer the promise of analytic discrimination of Iberian dry-cured ham categories. In addition, these determinations, in combination with chemometrics, may prove extremely useful to authenticate many foods containing high to moderate amounts of lipids.     

特高压直流输电线路暂态能量保护

在分析±800 kV特高压直流输电线路区内外故障、雷击等暂态过程的基础上,提出了一种特高压直流输电线路暂态能量保护新原理。该原理根据各种暂态过程中线路两侧低频能量差值的故障特征,实现了区内故障及其故障极的快速准确识别。基于PSCAD/EMTDC的大量仿真验证,结果表明该保护原理简单、可靠、实用性强,具有绝对的选择性,不受雷击干扰、两极线路电磁耦合和换相失败的影响,高阻接地故障仍具有足够的灵敏性,能满足特高压直流线路对保护性能的要求,可在当前高压直流控制保护系统硬件条件下实现。     

多波速度比参数含气性识别研究与应用

基于三维三分量地震资料,采用纵横波联合反演、递推计算等方法,可以提取多波速度比参数,包括横波与纵波速度比、横波与转换波速度比、转换波与纵波速度比,以及据此衍生出来的相关参数（如速度比导数）。以泊松比与纵横波速度比之间的数学关系为基础,利用纵波与转换波的传播特征,推导出采用泊松比或纵横波速度比表述的横波与转换波速度比、转换波与纵波速度比、转换波与纵波速度比对纵波速度的一阶导数、转换波与纵波速度比对泊松比的一阶导数。这些参数对岩性、含气性比较敏感,是油气预测中一类新的实用参数。将上述参数用于四川盆地西部深层须家河组低渗透-致密裂缝性气藏的含气性检测,发现多波速度比参数异常强、裂缝发育好的区域,是天然气富集的优质储层带。     

Species determination of pine nuts in commercial samples causing pine nut syndrome

Consumption of pine nuts from the species of Pinus armandii has been reported to cause dysgeusia, commonly known as pine mouth, or pine nut syndrome (PNS). However, the number of reports on pine nut consumptions of the different species and PNS is limited. This leaves open the possibility that other pine species than P. armandii could be involved in PNS as well. This study investigated 18 samples involved in PNS and received at the Danish Veterinary and Food Administration in 2011 through 2012. Samples were subjected to gas chromatographic analysis of fatty acids. The content of 11 individual fatty acids was used together with the diagnostic index and the sum of Δ5-fatty acids as diagnostic parameters. Diagnostic parameters from samples were then compared to reference material and literature data to determine the species. In a limited number of samples, the diagnostic parameters matched neither our reference materials nor literature data. However, the morphology, the fatty acid analysis, and externally obtained DNA sequencing data suggest a P. armandii subspecies or a variety. With these possible P. armandii subspecies, P. armandii was identified in all analyzed samples. The application of principal component analysis (PCA) to the data set showed a satisfactory separation of the majority of the 13 pine species included in the study.     

Inhibitory of multiple antifungal components produced by Lactobacillus plantarum K35 on growth,aflatoxin production and ultrastructure alterations of Aspergillus flavus and Aspergillus parasiticus

The antifungal activity of Lactobacillus plantarum K35 isolated from traditional Thai fermented rice noodle was evaluated against the growth and aflatoxin production of Aspergillus flavus TISTR304 and Aspergillus parasiticus TISTR3276. Multiple antifungal compounds secreted by L. plantarum were firstly analyzed using GC–MS in parallel to the ultrastructure alteration of the treated fungi. L. plantarum K35 supernatant caused significant reduction of the fungal growth and aflatoxin production. The antifungal activity was pH-dependent and favorable to acidic conditions whereas the catalase treatment had no influence indicating no involvement of hydrogen peroxide in the inhibition. Antifungal substances were resistant to sterilization and proteolytic enzymes including trypsin and proteinase K. The major components, apart from lactic acid, were 2-butyl-4-hexyloctahydro-1H-indene (19.55%), oleic acid (10.52%) and palmitic acid (7.27%). Other minor antifungal compounds included linoleic acid (2.11%), 2,4-di-tert-butylphenol (1.84%), stearic acid (1.55%), 3-phenyllactic acid (1.42%) and pyroglutamic acid (1.07%). The morphological changes of the fungi exposed to the supernatant were observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). L. plantarum K35 supernatant caused severe damage to the cell wall and cytoplasmic membrane leading to a massive loss of cytoplasmic content, the formation of membrane-bound vesicles, and complete destruction of membranous organelles including mitochondria and nucleus.     

基于谱分解的薄层预测方法

本文基于复信号的瞬时特征,实现了基于雷克子波的两步匹配追踪（Matching Pursuit,MP）算法。借助三层双界面反射系数模型推导了地震信号偶分量的峰值频率与薄层厚度的一一对应关系,结合时频分辨率较高的MP分解,提出了利用反射系数序列的奇、偶分解原理求取薄层厚度的新方法：地震记录在地震子波为零相位时关于某时窗中心的奇、偶分量,相当于对应反射系数关于该时窗中心的奇、偶分解与子波的褶积结果;在子波主频确定的情况下,偶分量峰值频率和层厚之间关系,不再受限于薄层反射系数因素的制约,两者之间满足一一对应关系;通过MP分解得到偶分量峰值频率,代入峰值频率—薄层厚度关系曲线模板即可估算薄层厚度。模型试算验证了方法的可行性。     

页岩储层矿物组分分形特征研究

页岩储层矿物组分的含量及其分布特征是水力压裂的重要参考因素。以中扬子地区下寒武统水井沱组页岩为例,利用ImageJ软件对页岩CT扫描图像进行处理和分析,研究页岩储层中矿物组分的分布特征,并讨论矿物组分含量和分形维数之间的关系。结果表明:页岩CT图像上矿物组分的密度比有机质和孔隙的密度要大得多,可以根据CT图像的灰度值识别矿物组分。页岩中矿物组分含量越多,矿物组分的分形维数也越大。在矿物组分含量相近的情况下,矿物组分结构越复杂,其分形维数也越大。基于灰度CT图像的页岩矿物组分分形特征研究是页岩储层评价的有效补充,可以更好地指导页岩脆性评价。