准噶尔盆地边缘山区的初步静校正

本文讨论了准噶尔盆地边缘山区替代速度对初步静校正精度的影响。通过用相遇法[1]从多次覆盖反射地震采集记录中的初至折射波计算基岩面的t0时和选用合适的替代速度进行初步静校正，在很大程度上消除了表层不均匀和基岩面起伏引起的大静校量，使静校误差控制在自动静校的要求范围之内、从而提高了速度谱和水平叠加剖面的质量。     

A force modulation study on crystallization process in ferroelectric vinylidene fluoride and trifluoroethylene copolymer films

This paper introduces the Force Modulation technique to the study of crystallization process in ferroelectric vinylidene fluoride and trifluoroethylene copolymer films. Using this technique we have successfully visualized ferroelectric crystalline domains and observed that these ferroelectric domains grow out from amorphous phase, unite into strip-like structures, and finally congregate into a union. Force Modulation can weaken the influence of topography on imaging of ferroelectric domains, and reveal more details, which are difficult to be observed in topographical image.     

基于椭圆曲线上EIGamal公钥体制的数字签名方案

论文提出了基于椭圆曲线上EIGamal加密体制的数字签名方案，并出于安全性的考虑进行了一点改动。另外，应用了Tate配对对签名进行验证。     

Investigation into the time-dependent behaviour of reinforced concrete specimens strengthened with externally bonded CFRP-plates

This paper deals with the influence of an external CFRP-reinforcement on the time dependent behaviour of flexural concrete beams. For this purpose, four reinforced concrete beams are tested in relaxation under three-point bending. Three of the four are strengthened with a composite plate bonded to their tensile soffit. The latter is not strengthened. The phenomenon of relaxation leads to a decrease in the loading force in the course of time. The test results are analysed in three ways: the first is a comparison between the global behaviour of the four beams. The second is a detailed analysis of the internal equilibrium of the beams in the course of time. The third is a global approach based on an incremental method suited to time analysis of composite structures. It can be concluded that composite reinforcement has a positive influence on the long term behaviour of strengthened beams. Their time dependent behaviours are different depending on whether the beam is pre-cracked before being strengthened. This difference may be taken into account using a coefficient of influence applied to the composite reinforcement. The existence of a period of loading before strengthening has a positive influence on the long-term behaviour of the beam.     

常速度梯度射线追踪与二维层速度反演

速度问题是勘探地震学的核心 ,可以借助常速度梯度射线追踪方法 ,从反演的角度探讨速度建模问题。在射线追踪方面 ,从程函方程出发 ,将复杂的速度场剖分成小的矩形单元 ,并假设在每个矩形单元内速度具有常速度梯度 ,由此导出的一组常速度梯度射线追踪公式 ,可实现非均匀介质的射线追踪 ,具有适应性强、精度高和快速的优点。在层速度反演方面 ,采用相干速度反演的思想 ,根据各向同性介质中 ,零偏移距射线在界面处是法向入射的原理 ,建立了合成共中心点道集与射线深度偏移的正反演关系 ,由此利用合成共中心点道集与观测的共中心点道集逼近 ,采用层剥离方法进行层速度反演。通过理论推导与模型试算得到如下的认识与结论 :常速度梯度射线追踪具有较高的计算精度与效率 ,公式采用向量形式很容易推广到三维 ;确定层速度采用的是正反演相结合的方法 ,可得到稳定的速度场 ;该方法屏弃了基于双曲时矩关系确定层速度场的假设 ,使其能适应任意的速度分布。     

Machine-learning paradigms for selecting ecologically significant input variables

Harmful algal blooms, which are considered a serious environmental problem nowadays, occur in coastal waters in many parts of the world. They cause acute ecological damage and ensuing economic losses, due to fish kills and shellfish poisoning as well as public health threats posed by toxic blooms. Recently, data-driven models including machine-learning (ML) techniques have been employed to mimic dynamics of algal blooms. One of the most important steps in the application of a ML technique is the selection of significant model input variables. In the present paper, we use two extensively used ML techniques, artificial neural networks (ANN) and genetic programming (GP) for selecting the significant input variables. The efficacy of these techniques is first demonstrated on a test problem with known dependence and then they are applied to a real-world case study of water quality data from Tolo Harbour, Hong Kong. These ML techniques overcome some of the limitations of the currently used techniques for input variable selection, a review of which is also presented. The interpretation of the weights of the trained ANN and the GP evolved equations demonstrate their ability to identify the ecologically significant variables precisely. The significant variables suggested by the ML techniques also indicate chlorophyll-a (Chl-a) itself to be the most significant input in predicting the algal blooms, suggesting an auto-regressive nature or persistence in the algal bloom dynamics, which may be related to the long flushing time in the semi-enclosed coastal waters. The study also confirms the previous understanding that the algal blooms in coastal waters of Hong Kong often occur with a life cycle of the order of 1–2 weeks.     

辽河盆地新生代断裂与油气关系

辽河盆地是一个以新生代为主要成盆期的裂谷盆地,断裂和断陷活动是新生代构造变形的主导方式.断裂幕式活动,引起沉积空间和湖盆范围周期性扩张与收缩,控制了生储盖及其组合特征.断裂的发育对油气富集有着十分重要的影响,它控制了油气运移和聚集.该文较全面和系统地总结了断裂对油气的影响,认为主干断裂控制油气富集,断裂发育演化对油气资源有重要的影响.次级断裂对油气的侧向封堵及油气的再分配有重要的作用,断层的开启性又导致不同区块油气贫富不一致.断裂控制了特殊储层裂缝发育,对圈闭形成起到了关键的作用.因此,正确认识断裂对勘探具有十分重要的意义.