多分量数据全波形反演在气藏检测中的关键问题——以苏里格气田为例

苏里格气田是中国典型的致密砂岩气藏，构造简单、平缓，横向非均质性强，有效储层与围岩声学特征差别小，地震响应不明显，常规地震监测方法预测难度大，但气田含气砂岩泊松比低，是地震气藏检测的有效参数。利用弹性全波形反演精度高和能处理复杂非均质介质的优势，反演地层拉梅常数、剪切模量和密度，并计算泊松比，从而进行气藏预测。重点阐述了苏里格气田多分量数据全波形反演初始模型建模、先验模型建模和地震数据预处理3个关键问题的处理方法。二维三分量数据反演和"甜点"预测结果表明：①对于具有强非均质性的苏里格气田，利用全波形反演获得精度较高的地层弹性参数能显著提高气藏预测的准确度；②苏里格地区构造简单、平缓，利用常规叠加速度并结合构造解释可以建立比较好的初始模型，从而有效地解决了周波跳跃和局部极小的难题；③先验知识的约束和地震数据的预处理是全波形反演成功应用于苏里格气田气藏检测的关键。     

Validation of a 3D multiphase-multicomponent CFD model for accidental liquid and gaseous hydrogen releases

As hydrogen-air mixtures are flammable in a wide range of concentrations and the minimum ignition energy is low compared to hydrocarbon fuels, the safe handling of hydrogen is of utmost importance. Additional hazards may arise with the accidental spill of liquid hydrogen. Such a release of LH2 leads to a formation of a cryogenic pool, a dynamic vaporization process, and consequently a dispersion of gaseous hydrogen into the environment. Several LH2 release experiments as well as modeling approaches address this phenomenology. In contrast to existing approaches a new CFD model capable of simulating liquid and gaseous distribution was developed at Forschungszentrum Jülich. It is validated against existing experiments and yields no substantial lacks in the physical model and reveals a qualitatively consistent prediction. Nevertheless, the deviation between experiment and simulation raises questions on the completeness of the database, in particular with regard to the boundary conditions and available measurements.     

Robust adaptive control for unmatched systems with guaranteed parameter estimation convergence

This paper provides a modified model reference adaptive control (MRAC) scheme to achieve better transient control performance for systems with unknown unmatched dynamics, where an adaptive law with guaranteed convergence is introduced. We first revisit the standard MRAC system and analyze the tracking error bound by using L₂‐norm and Cauchy‐Schwartz inequality. Based on this analysis, we suggest a feasible way to compensate the undesired transient dynamics induced by the gradient descent–based adaptive laws subject to sluggish convergence or even parameter drift. Then, a modified adaptive law with an alternative leakage term containing the parameter estimation error is developed. With this adaptive law, the convergence of both the estimation error and tracking error can be proved simultaneously. This enhanced convergence property can contribute to deriving smoother control signal and improved control response. Moreover, this paper provides a simple and numerically feasible approach to online verify the well‐known persistent excitation condition by testing the positive definiteness of an introduced auxiliary matrix. Comparative simulations based on a benchmark 3‐DOF helicopter model are given to validate the effectiveness of the proposed MRAC approach and show the improved performance over several other MRAC schemes.     

基于IMCT理论的CaO-SiO2-MgO-Al2O3-Na2O渣系的脱硫热力学模型

 为了精确表征含Na2O渣系的脱硫能力，改善脱硫效果，基于熔渣离子与分子共存理论（IMCT）建立了CaO-SiO2-MgO-Al2O3-Na2O渣系结构单元的作用浓度计算模型和1 753 K时该渣系的脱硫热力学模型。并对渣系的总硫分配比及各自硫分配比的影响因素进行了讨论分析。理论结果表明，除LS， MgS外，随着Al2O3质量分数的增加，该渣系的脱硫能力明显下降，而MgO和Na2O质量分数的增加，对提高渣系的脱硫能力具有明显的促进作用。此外，少量的Na2O即可表现出很强的脱硫效果，这为含有Na2O的冶金二次资源在铁水脱硫过程中的应用以及铁水脱硫渣系的优化提供了必要的理论依据。     

考虑节点过载的碳排放空间关联系统级联失效模型

为提高突发事件级联失效对现实碳排放关联系统破坏程度的评估可信性，在传统复杂网络的"负载-容量"级联失效模型基础上，考虑个体成员对负载的冗余能力，提出一种过载失效概率，构建了考虑节点过载状态的级联失效模型，并基于节点特性提出了6种过载节点负载分配策略。仿真结果表明：在过载节点负载分配策略中，综合分配策略整体上较优，能够有效控制级联失效的规模，增加网络鲁棒性；在一定范围内提升过载参数有助于降低级联失效的影响，但提升到一定程度时改善效果不明显；在不同负载分配策略下，剩余系数存在一个最优值，容量可调参数存在最优区间，可以使碳排放关联网络保持较好鲁棒性的同时，花费较小的构建成本，其中紧密度分配策略对应的网络构建成本较高。     

基于强化学习的HP模型优化方法研究

蛋白质结构预测问题一直是生物信息学中的重要问题。基于疏水极性模型的蛋白质二维结构预测问题是一个典型的NP难问题。目前疏水极性模型优化的方法有贪心算法、粒子群算法、遗传算法、蚁群算法和蒙特卡罗模拟方法等，但这些方法成功收敛的鲁棒性不高，容易陷入局部最优。由此提出一种基于强化学习的HP模型优化方法，利用其连续马尔可夫最优决策与最大化全局累计回报的特点，在全状态空间中，构建基于能量函数的奖赏函数，引入刚性重叠检测规则，充分挖掘生物序列中的全局进化关系，从而进行有效与稳定的预测。以3条经典论文序列和5条Uniref50序列为实验对象，与贪心算法和粒子群算法分别进行了鲁棒性、收敛性与运行时间的比较。贪心算法只能在62.5%的序列上进行收敛，该文方法能在5万次训练后稳定的在所有序列上达到了收敛。与粒子群算法相比，两者都能找到最低能量结构，但该文的运行时间较粒子群算法降低了63.9%。     

硅酸盐水泥基胶凝材料体系水化热计算研究

基于传统水化热模型计算水泥水化热,建立矿物掺合料水化热计算公式;采用直接法测定掺粉煤灰、矿渣条件下普通硅酸盐水泥和低热水泥基胶凝材料体系1~7 d水化热。计算结果与实测结果对比表明:矿物掺和料水化热双指数计算公式可表征普通硅酸盐水泥和低热水泥基胶凝材料体系下粉煤灰和矿渣1~7 d水化热,可采用此法结合水泥水化热计算方法进行以水化热作为目标函数的胶凝材料体系优化设计。