数值分析方法在VAR中的应用

针对VAR方法低估风险和压力测试方法分类错综复杂的缺陷,开发了一种估计风险的新方法.应用数值分析中的插值方法,拟合系统压力测试方法得出的数值点来修改VAR方法中的正态分布曲线,从而得到新的VAR,命名为SVAR.实证研究表明,SVAR方法较Delta-正态方法和GARCH(1,1)方法更为优越.     

Graphene-Au nanoparticle based electrochemical immunosensor for fish pathogen Aphanomyces invadans detection

Epizootic ulcerative syndrome (EUS) that is primarily caused by an invasive oomycete fungus Aphanomyces invadans is a devastating fish disease. Rapid diagnosis of EUS is significantly important for the control and treatment of this highly invasive disease. In our study, a label-free immunosensor constructed with G-AuNPs/SAM-Ab-BSA/GCE was proposed for the determination of Aphanomyces invadans. The electrode was prepared by the immobilization of anti-mycelium antibodies on graphene-AuNPs nanocomposite-cysteamine monolayers modified GCE. The optimized parameters were as follows: 90 min as the immersion time of SAM modified electrode in the anti-mycelium solution, 0.20 µg/mL as the concentration of anti-mycelium solution and 10 min as the interaction time of immunoreaction. The immunosensors exhibited low limit detection of 309 ng/mL and good reproducibility.     

Preparation of pompon-like Co-B nanoalloy by a room-temperature solid-state-reaction as a catalyst for hydrolysis of borohydride solution

Pompon-like Co-B alloy composed of nanosheets with a large specific surface area of 202.4 m² g^?1 was synthesized via a facile room-temperature solid-state-reaction. By changing the mass ratios of CoCl₂·6H₂O to CO(NH₂)₂ in the synthesis, the morphology of the Co-B alloy can be controlled. Correspondingly, the specific surface area can increase from ca. 43.4–202.4 m² g^?1. When the pompon-like Co-B severs as a catalyst for the hydrolysis of NaBH₄, the hydrogen generation rate can be up to $8\text{.}26{\text{L}}_{\text{hydrogen}}{\text{min}}^{\mathrm{?}1}{{\text{g}}_{\text{catalyst}}}^{\mathrm{?}1}$. This value is larger compared with those of many other Co-B nanoalloys in previous reports. Additionally, the corresponding activated energy for the hydrolytic reaction is as low as 25 kJ mol^?1, hinting that the pompon-like Co-B catalyst possesses superior catalytic performance. The pompon-like Co-B alloy has the advantages of low cost, good recoverability, as well as high activity, which may find practical application in NaBH₄ hydrolysis for hydrogen production.     

基于风味指纹谱的肉脯加工阶段判别

应用气相离子迁移谱(gas chromatography-ion mobility spectrometry,GC-IMS)对肉脯不同加工阶段的挥发性有机物(volatile organic compounds,VOCs)进行分析,构建不同加工阶段肉脯的GC-IMS风味指纹图谱,实现不同加工阶段肉脯的判别分析。采用GC-IMS对肉脯加工过程中产生的原料肉、拌料肉、发酵肉、半成品肉和成品肉的VOCs进行检测和分析,对选取的GC-IMS图谱特征区域信号进行主成分分析,并结合k最近邻(k nearest neighbor,kNN)模式识别方法对不同加工阶段的肉脯进行分类识别。结果表明,肉脯在加工过程中主要的VOCs为醇类、醛类、酸类、酮类、杂环化合物、芳香烃以及酯类,GC-IMS风味指纹谱结合化学计量学方法能够有效区分各加工阶段的肉脯样品,为研究加工工艺对肉脯风味的影响提供了一种新的分析技术,也为肉制品的品质鉴别提供理论基础。     

垂直测井资料解释方法及应用

垂直测井是磁测井的一种类型,能够监测油水井套管的腐蚀类型及损伤程度。在以前垂直测井资料定性解释的基础上提出垂直测定量解释方法并绘出解释图版,使垂直测井资料解释方法更趋完善,有利于精细评价套管腐蚀状况。     

Combined effect of Sn addition and pre-ageing on natural secondary and artificial ageing of Al–Mg–Si alloys

Journal of Materials Science - Both Sn addition and pre-ageing are known to be effective in maintaining the artificial ageing potential after natural ageing of Al–Mg–Si alloys. In this...     

基于GC-IMS技术的香米共享风味指纹谱构建

为提取广西香米中的共享风味指纹信息,实现广西、五常区域香米样品的快速判别,本研究采用气相离子迁移谱(Gas chromatography-ion mobility Spectrometry,GC-IMS)分析53个香米样品的挥发性风味物质成分,采用图谱预处理结合自动阈值分割方法提取二维图谱中能够表征广西香米中共有风味成...     

银杏全资源主要成分与功能活性

我国是银杏的主要产地之一,银杏资源十分丰富,其食用和药用价值也十分巨大.为了更精确地利用具有"药食同源"特性的银杏资源进行深度开发,就必然需要清晰地掌握它的化学成分与功效.因此,本文从银杏叶、银杏花、银杏果和银杏树全资源的角度系统地介绍与分析了银杏各部位的化学组成.同时,还对银杏各部分中相关成分的具体功能活性进行了详细...     

注浆技术在联络通道开挖施工中的应用

广州市轨道交通三号线某盾构区间联络通道的施工过程中,因联络通道位置处土体遇水软化而导致出现了多次涌水、涌泥的险情,经分析后决定采取洞内注浆加固改良土体的措施,成功实现了软弱地层中联络通道及废水泵房的开挖.本文通过工程案例介绍了联络通道开挖过程中使用注浆技术达到超前支护的目的,克服了联络通道施工中的安全、质量、技术难题,为企业创造了良好的经济效益和社会效益,为今后类似地质条件联络通道施工提供了参考.