序约束下正态总体均值和方差极大似然估计的数值解法

本文讨论了k个独立正态总体的均值和方差同时在简单半序约束下的极大似然估计的求解问题，给出了计算极大估计的迭代算法，且证明该算法收敛。     

四硫代富瓦烯衍生物的合成和表征

通过4-二甲氨基吡啶(DMAP)、二环己基碳二亚胺(DCC)催化体系的酯化反应和三乙基磷酸酯的耦合反应得到四硫代富瓦烯衍生物,通过核磁、质谱、红外等手段对所合成的四硫代富瓦烯的衍生物进行了纯度和结构的确认,使用偏光显微镜,差示扫描量热仪等,对其热力学性能和液晶性能进行了表征,证明它是一种室温液晶分子,对它进行了化学氧化实验,研究了四硫代富瓦烯衍生物的氧化还原性质.     

Fluid-solid coupling model for studying wellbore instability in drilling of gas hydrate bearing sediments

As the oil or gas exploration and development activities in deep and ultra- deep waters become more and more, encountering gas hydrate bearing sediments （HBS） is almost inevitable. The variation in temperature and pressure can destabilize gas hydrate in nearby formation around the borehole, which may reduce the strength of the formation and result in wellbore instability. A non-isothermal, transient, two-phase, and fluid-solid coupling mathematical model is proposed to simulate the complex stability performance of a wellbore drilled in HBS. In the model, the phase transition of hydrate dissociation, the heat exchange between drilling fluid and formation, the change of mechanical and petrophysical properties, the gas-water two-phase seepage, and its interaction with rock deformation are considered. A finite element simulator is developed, and the impact of drilling mud on wellbore instability in HBS is simulated. Results indicate that the re- duction in pressure and the increase in temperature of the drilling fluid can accelerate hydrate decomposition and lead to mechanical properties getting worse tremendously. The cohesion decreases by 25% when the hydrate totally dissociates in HBS. This easily causes the wellbore instability accordingly. In the first two hours after the formation is drilled, the regions of hydrate dissociation and wellbore instability extend quickly. Then, with the soaking time of drilling fluid increasing, the regions enlarge little. Choosing the low temperature drilling fluid and increasing the drilling mud pressure appropriately can benefit the wellbore stability of HBS. The established model turns out to be an efficient tool in numerical studies of the hydrate dissociation behavior and wellbore stability of HBS.     

形体细胞的MCEM模型及其光散射分布特征

针对光散射细胞微粒测量中真实形体细胞的取向对测量结果的影响问题，基于Rayleigh-Debye-Gans理论和双椭球核式(CEM)模型在应用中的差异，建立了CEM的修正模型(MCEM)，根据此模型系统讨论了细胞在不同入射角变化情况下其光散射强度分布所产生的变化，得到了不同入射角下有核细胞光散射强度分布与有核细胞相关物理特征量的动态响应关系；此外，对有核细胞光散射强度分布进行拟合，得到了有核细胞光散射强度分布函数。误差分析表明：拟合结果可有效地应用于真实细胞光散射测量中的数值反演计算。