共转换点速度分析

转换波共转换点相对于共中心点的偏移距离随着纵横波速度比、深度以及炮检距等因素的变化而变化，因此不能采用固定道集的方法进行转换波速度分析，而应当在速度比与深度等因素变化时，速度分析所用的道集也做相应的变化。本文提出了一种随着速度比与转换点深度的变化而动态抽道的转换波速度分析方法，实现了扫描叠加速度、转换点深度与共转换点道集的一一对应。此法应是一种真正意义上的共转换点速度分析技术。经理论模型与实际地震资料验证，表明了该方法的有效性。     

Dietary fats and F2-isoprostanes: A review of the clinical evidence

Evidence supports that a high dietary fat intake increases oxidative stress and the risk of diet-induced metabolic disorders such as obesity, diabetes and cardiovascular diseases. F₂-isoprostanes (F₂-isoP) are formed by the non-enzymatic oxidation of arachidonic acid and are widely used as reliable biomarkers of oxidative stress in clinical studies. Dietary fats may influence F₂-isoP levels, as they (1) are metabolic substrates for their formation, (2) modify the lipid composition of tissues, and (3) affect the plasma lipoprotein concentrations which are involved in F₂-isoP transport. This review examined the latest clinical evidence on how dietary fats can affect blood circulation and excretion of F₂-isoP in individuals with healthy or deteriorated metabolic profiles. Clinical studies reported that saturated or monounsaturated fat-rich diets did not affect F₂-isoP levels in adults with healthy or deteriorated metabolic profiles. Though, ω-3 polyunsaturated fatty acids decreased F₂-isoP levels in numerous studies, whereas trans-fatty acids raised F₂-isoP excretion. Yet, the reported heterogeneous results reveal important considerations, such as the health status of the participants, the biological fluids used to determine F₂-isoP, the analytical methods employed and the specific F₂-isoP isomers detected. Therefore, future clinical studies should be designed in order to consider these issues in the studies of the effects of fat intake on oxidative stress.     

二维大地电磁数据的聚焦反演算法探讨

 文中简要分析了当前地球物理反演中几种常用的模型目标函数，并根据聚焦反演成像方法的基本理论，在大地电磁反演目标函数中引入了一个新的稳定泛函，以代替传统最小构造或最大平滑准则下的模型目标函数。通过对自适应正则化共轭梯度法解最优化问题过程的研究，以及对几个典型模型的试算，并将其结果与传统反演算法结果进行对比分析，表明了本文方法的正确性和较高的计算精度。最后对雷—琼拗陷一条实测的测线的MT资料进行聚焦反演成像处理，并与同一测线的地震资料进行对比表明,聚焦反演结果具有很高的准确性。     

南秦岭中段亚碱性-碱性岩板块构造环境及岩浆演化

从地质特征及室内各种测试入手,对比国外典型地区同类岩石成分特征,运用多种分析方法,对南秦岭中段广泛分布的亚碱性-碱性岩进行深入研究,确定了岩石形成的构造背景、成岩时代,并对岩石多样性原因与演化机理进行了探讨。岩石产于大陆板内张性深大断裂环境,橄榄拉斑玄武岩浆为本区的原始岩浆。     

Aromatic Phosphonates: A Novel Group of Emitters Showing Blue Ultralong Room Temperature Phosphorescence

In recent years, there has been a growing interest in purely organic materials showing ultralong room-temperature phosphorescence with lifetimes in the range of seconds. Still, the longest known phosphorescence lifetimes are only achieved with crystalline systems so far. Here, a rational design of a completely new family of halogen-free organic luminescent derivatives in amorphous matrices, displaying both conventional fluorescence and phosphorescence is reported. Hydrogen bonding between the newly developed emitters and an ethylene-vinyl alcohol copolymer (Exceval) matrix, which efficiently suppresses vibrational dissipation, enables bright long-lived phosphorescence with lifetimes up to 2.6 s at around 480 nm. The importance of the chosen matrix is shown as well as the implementation in an organic programmable luminescent tag.     

Blue‐Light‐Absorbing Thin Films Showing Ultralong Room‐Temperature Phosphorescence

The development of organic materials displaying ultralong room‐temperature phosphorescence (URTP) is a material design‐rich research field with growing interest recently, as the luminescence characteristics have started to become interesting for applications. However, the development of systems performing under aerated conditions remains a formidable challenge. Furthermore, in the vast majority of molecular examples, the respective absorption bands of the compounds are in the near ultraviolet (UV) range, which makes UV excitation sources necessary. Herein, the synthesis and detailed analysis of new luminescent organic metal‐free materials displaying, in addition to conventional fluorescence, phosphorescence with lifetimes up to 700 ms and tailored redshifted absorption bands, allowing for deep blue excitation, are reported. For the most promising targets, their application is demonstrated in the form of organic programmable tags that have been recently developed. These tags make use of reversible activation and deactivation of the URTP by toggling between the presence and absence of molecular oxygen. In this case, the activation can be achieved with visible light excitation, which greatly increases the use case scenarios by making UV sources obsolete.     

DMO和叠前时间偏移的共同起点

DMO和叠前时间偏移对于改善速度分析及叠加效果,最终提高剖面成像质量都是很有用的工具,一般在共偏移距道集中进行。其实现方法有多种,如等价偏移距方法（equivalent offset migration,Bancroft et al,1994)、DMO PSI(prestack imaging)方法（Gardner,1986）和非成像的炮集偏移（non-imaging shot-record migration,Berryhill,1996）等。这些方法的一个共同特点是用一个新定义的偏移距替代原来的偏移距。在每一种方法中,成像过程都归结为以新偏移距定义的共反射点双曲线型时－距关系上的动校正。本文中,我们证明了不同方法的DMO和叠前时间偏移有其共同起点－－双平方根算子,说明它们在原理上是等价的;最后我们提出了基于波动方程的DMO和叠前时间偏移方法。     

低沸点工质热力学性质的计算及其在船舶余热回收动力系统研究中的应用

本文利用Lee—Kesler方程和Martin—Hou(侯)方程计算低沸点工质的热力学性质,对五种低沸点工质的热力学性质进行了计算。并对船舶柴油机低沸点工质余热回收动力系统参数进行了优化计算,验证了计算方法及所编制的计算机程序的有效性。所编制的程序不仅可以用于能量回收系统的热力计算和系统参数的优选,还具备编制热力学性质表的功能。     

Improved Arabic-to-English statistical machine translation by reordering post-verbal subjects for word alignment

We study challenges raised by the order of Arabic verbs and their subjects in statistical machine translation (SMT). We show that the boundaries of post-verbal subjects (VS) are hard to detect accurately, even with a state-of-the-art Arabic dependency parser. In addition, VS constructions have highly ambiguous reordering patterns when translated to English, and these patterns are very different for matrix (main clause) VS and non-matrix (subordinate clause) VS. Based on this analysis, we propose a novel method for leveraging VS information in SMT: we reorder VS constructions into pre-verbal (SV) order for word alignment. Unlike previous approaches to source-side reordering, phrase extraction and decoding are performed using the original Arabic word order. This strategy significantly improves BLEU and TER scores, even on a strong large-scale baseline. Limiting reordering to matrix VS yields further improvements.     

一座小型建筑空调动态负荷的ANN预测

人工神经网络(ANN)具有良好的非线性品质和极高的拟合精度,是一种崭新的非线性建模和预测方法。本文针对一座小型建筑建立了空调动态负荷预测的BP模型,并着重在模型结构和训练算法两个方面进行改进,提高了模型的训练速度和预测精度。