电磁流动成像测井识别气-水层流的信号处理方法

针对大斜度或水平气井中最常见的气-水分层流动,研究利用电磁流动成像测井判别分层流和波状流的方法.首先,分析水平或微倾圆形管道内较常见的气-水两相流型在管道截面上的特征,建立流体分布模型;其次,模拟流体分布模型的电磁流动成像测井响应,分析仿真数据特点;再次,提取仿真数据中与流体分布相关的特征参数,该参数不仅用于判定流体分布模型,而且用于计算分层流模型中的水层高度,从而求取持水率;最后,研究水平气-水两相流型在流动截面上流体分布模型的变化规律,实现气-水层流判别.仿真数据研究结果表明,用这种方法可以实现气-水层流判别和持水率求取,避免了图像重建的过程,计算简单速度较快.     

一种解决调频连续测距中测距模糊方法

通过对锯齿调频连续测距系统的差频信号分析可知,由于观测时间的随机性导致同一距离上对应两个不同的差频频率。对差频信号进行时域和频域分析发现,利用两次混频的方法能够解决这种测距模糊问题,使信号处理单元的输出信号频率和距离一一对应。利用仿真软件,得到信号处理过程中的时频关系曲线,验证了这种信号处理方法的有效性。     

不确定条件下不连续创新项目期权价值优化模型

为探讨不确定性对不连续创新项目期权价值及投资策略的影响,通过引入泊松跳跃过程模拟项目价值的不连续变化建立了不连续创新项目的期权价值优化模型,将技术、市场、组织与资源不确定性分别表示为项目产业化成功率、项目价值和投资成本的不确定性,然后具体解析了不连续变化的跳跃强度、跳跃幅度、跳跃幅度波动率等不确定性对不连续创新项目最优投资策略的影响以及不确定性与期权价值的关系,最后通过蒙特卡罗模拟检验了模型的有效性.模型将现有研究扩展到投资成本亦为不确定的情形,可为不连续创新项目投资和项目价值与风险评估提供决策参考.     

Direct algorithms for constructing high-order conservation laws of nonlinear partial differential equations〖CB〗

提出了构造非线性偏微分方程高阶守恒律的直接法并在Maple上实现,算法易操作,效率高.作为算法的应用,考虑了许多高维非线性偏微分方程,如Caudrey-Dodd-Gibbon-Sawada-Kotera方程、Boiti-Leon-Manna-Pempinelli方程和(2+1)-维Burgers方程以及It?方程组,得到了它们的新的高阶守恒律.该算法还可用于构造更高维更高阶的守恒律,亦可推广至微分-差分方程(组).     

同位素内标法对水产品中硝基呋喃代谢物液相色谱-串联质谱法测定

建立了水产品中硝基呋喃类代谢物残留量的同位素内标定量液相色谱-串联质谱法测定。样品经稀盐酸水解,邻硝基苯甲醛衍生,乙酸乙酯提取净化后,用液相色谱-串联质谱法通过正离子扫描多反应监测模式检测,稳定同位素内标定量。本方法的线性范围为1.25～10μg/kg,4种硝基呋喃代谢物的线性相关系数均在0.993 2以上,4种化合物...     

G-morphic环的若干结果

本文证明了幺π-正则环与左G-morphic的π-正则环的等价性;以及在约化条件下,G-morphic环与其他一些特殊环的联系;以及在ZI环类中,左(右)GP-V-(GP-V′-)的G-morphic环与强正则环的等价性.     

仿射反变条件下Newton迭代法的半局部收敛性

研究了一阶导数满足仿射反变ω-条件下,Newton迭代法在求解非线性算子方程时的半局部收敛性.这种ω-条件包含了仿射反变Lipschitz条件和仿射反变Hlder条件作为特殊情形.此外,得到了相应迭代残余(‖F(xk)‖)的误差估计,并推广了相应结果.     

极大局部边连通有向图的度条件

对有向图D=(V(D),E(D)),顶点u和v的局部边连通度λ(u,v)=min {X:X∈E(D),D-X中不存在从u到v的路}.若对D中任意两个顶点u和v,λ(u,v)=nin{d+(u),d-(v)},称D为极大局部边连通的.笔者得到了有向图是极大局部边连通的两个度条件.推广了别人的三个结果.     

Response of the northwestern Pacific upper water δ~(13)C to the last deglacial ventilation of the deep Southern Ocean

The deglacial δ~13C minimum events that originated from the ventilation of the deep Southern Ocean around Antarctica, have been recorded in a range of marine sediments from the southern to tropical oceans in late Pleistocene. However, the broad δ~13C minimum event was also reported as far as to the northern middle latitudes, in northwestern Pacific marginal sea areas, during the last deglaciation. In the northwestern Pacific, forcing from the northern high latitudes is strongly expressed, while the records of in- fluence from the southern high latitudes are few. The Kuroshio Source Region (KSR) forms a boundary between the northwestern Pacific and the southern, tropical Pacific. So, high-resolution planktonic foraminiferal records in core MD06-3054 from the KSR are well positioned to identify signals from the southern hemisphere in the northwestern Pacific. Planktonic foraminiferal tests from the upper 1030 cm of the core were subject to AMS14C, carbon and oxygen isotopic measurements. A negative excursion was found to occur from about 20.0-6.0 ka BP in δ~13C records of both surface (Globigerinoides ruber) and subsurface (Pulleni- atina obliquiloculata) dwellers, but the overall trends of the two curves have reversed since 26.5 ka BP. Moreover, the δ~13C rec- ord of G. ruber (the surface dweller) shows a robust link to the record of atmospheric CO2, and its changes precede the records of P. obliquiloculata (the subsurface dweller). According to the hydrologic conditions, the broad δ~13C minimum event recorded in the KSR is also a response to the increasing ventilation of the deep Southern Ocean around Antarctica during the last deglaciation. The inconsistency between the records of the surface and subsurface dwellers was possibly caused by the ways that the low δ~13C signal was transmitted. Subsurface water primarily received the low δ~13C signal from the Antarctic Intermediate Water (AAIW), whereas the surface water was probably mainly impacted by atmospheric CO2 in the KSR. The records from the KSR confirm the deduction that the broad δ~13C minimum event in the Okinawa Trough was due to the impact of tropical Pacific surface water dur- ing the last deglaciation, and suggest that signals from the southern high latitudes also can be delivered to the northern middle latitudes.     

半B-(E,F)-凸约束单目标规划的对偶性

利用半B-(E,F)-凸函数的有关性质讨论了半B-(E,F).凸函数单目标规划的弱对偶定理,强对偶定理和逆对偶定理.