拉科斯特G型重力仪测量精度的统计分析

本文对拉科斯特G型重力仪特性、零漂特征、格值误差、测量精度以及《地震重力重复测量规范》中有关自差互差等问题作了讨论。认为:拉科斯特重力仪具有性能稳定,零漂小,观测精度高的优点,各仪器之间的系统误差不明显,格值误差极小;规范中规定的30×10~(-8)m/s~2自差和3S×10~(-8)m/s~2互差偏大。建议改为20×10~(-8)m/s~2和25×10~(-8)m/s~2为宜。     

基于多重分形特征和分项组合预测联合响应的滑坡预警预测研究

为准确掌握滑坡变形发展规律,基于滑坡变形监测成果构建滑坡预警预测模型,即先利用MF-DFA模型开展滑坡变形数据的多重分形特征分析,并进一步利用M-K分析构建双重判据（Δa指标判据和Δf(a)指标判据）进行滑坡预警研究;另外,在利用集成经验模态分解法对滑坡变形数据信息进行分离处理基础上,通过GOA-RNN-CT模型实现滑坡变形的分项组合预测。结果表明,h(q)值随波动函数q值减小而减小,说明滑坡变形数据具有多重分形特征,且预警分级研究表明,滑坡预警等级为Ⅱ级,即滑坡变形趋向不利方向发展;同时,通过变形预测分析认为,分项组合预测在滑坡变形预测中具有较优的预测效果和稳定性,且外推预测结果显示,滑坡变形会继续增加;最后,将多重分形特征研究结果和变形预测分析结果进行联合响应综合得出,滑坡现有预警等级相对不利,且后续变形仍会进一步增加,趋向不稳定方向发展,建议对滑坡采取必要防治措施。     

摩擦作用对西南低涡扰动的影响

西南低涡是对流层下层的中尺度扰动。本文在零级近似条件下,采用p坐标系的基本方程组,在边界层内设计两层模式。通过一定的简化方程组后,得到:当Z≤1/2[kL~2/(μ~2Knu~*)] 时,摩擦效应具有二重性,一方面使扰动减弱;另一方面使扰动增强,而前者的影响略大于后者,最终使扰动消失。频率随高度Z的降低而增加。当Z>1/2[kL~2/(μ~2Knμ~*)]时,摩擦作用甚微,几乎可以忽略不计。频率虽然有两个值,但随高度Z的增加,他们趋于一个常值。     

江苏常州4.2级地震前的重力变化

利用江苏地区2019~2021年流动重力观测资料,分析江苏省常州市4.2级地震前不同时间尺度下的重力场变化。结果表明：1）0.5 a尺度重力场变化图像较好地反映了此次地震下降-转折上升-持续上升-反向变化及零值线附近发震的演化过程;2）常州4.2级地震前0.5 a和1 a尺度下的重力场均显示,地震发生在重力变化零值线附近。     

零速修正在GNSS/INS紧组合导航中的应用研究

为研究零速修正在GNSS/INS紧组合导航中的应用,提出综合利用GNSS/INS紧组合解算速度、IMU原始数据和多普勒观测数据的零速判断准则以及零速状态下的紧组合数学模型,并通过车载测试进行验证。结果表明,该零速判断准则对载体静止状态的判断与实际情况吻合良好,零速修正能够有效抑制载体静止状态下的IMU传感器误差积累,尤其是在卫星观测质量不好时。相对于不使用零速修正,在较短静止时间内,采用零速修正算法可以使卫星信号正常时的载体位置、速度精度分别改善27%、35%;卫星信号中断30~120 s时,载体位置和速度精度分别改善16%~75%和87%~97%;但卫星信号正常与中断时,姿态改善效果都不明显。     

利用重力资料划分四川地区地震危险区

本文研究了四川地区均衡重力场空间变化和地震之间的关系,得出四川地区划分地震危险区的判据为:局部均衡重力异常为土30毫伽(±30×10~(-5)m/s~2),水平梯度模量大于0.5毫伽/公里(0.5×10~(-5)m/s~2/km)。同时还给出了重力场参数的平均值与各地震活动区特征值的相关系数。     

川西坳陷中段西部雷四段气藏沉积层序及其对储层的控制

为确定川西坳陷中段西部气藏的有利储层发育层段,利用薄片、岩心、测井、地震等资料,研究雷口坡组四段(简称雷四段)沉积层序,分析它对储层发育的控制。结果表明,雷四段可划分为一个完整的三级层序和三个四级层序,其中雷四上亚段对应上部四级层序,进一步划分为四个五级和多个六级高频层序,由向上变浅的高频沉积旋回组成;井间高频层序类型相似,横向一致性对比好,表明形成环境近似。雷四上亚段主要发育潮坪相的潮间带和潮下带亚相沉积,纵向上岩性变化频繁,横向上分布较为稳定;潮间带是储层发育的有利亚相,以Ⅱ、Ⅲ类储层为主,发育于上、下两个储层段中上部,对应五级和六级高频层序的中上部;高频层序反映的相对海平面变化控制潮间带有利岩相分布,影响后期成岩作用,是储层发育与空间展布的关键。     

异枝江蓠与凡纳滨对虾室内零换水混养

【目的】通过模拟养殖系统,在零换水条件下研究虾藻混养模式中藻体与对虾的生长。【方法】将异枝江蓠(Gracilaria bailinae)与凡纳滨对虾(Litopenaeus vannamei)混养,设置对虾混养密度(114±5)g/m~2,以及0、114、228、456、926 g/m~2 5个藻体密度梯度,混养时间为20 d,测定藻体和对虾的特定生长率,藻的光合特性参数,NH_4~+-N、NO_2~--N和NO_3~--N浓度。【结果】混养密度对藻体和对虾生长,藻的光合特性参数,NH_4~+-N、NO_2~--N和NO_3~--N浓度有显著影响(P0.05)。异枝江蓠密度为456g/m~2时,藻和对虾的特定生长率最高,分别为(1.63±0.04)%/d、(1.82±0.21)%/d;叶绿素荧光参数Fv/Fm和Y(Ⅱ)最高,分别为(0.61±0.00)μmol·m~(-2)·s~(-1)、(0.64±0.00)μmol·m~(-2)·s~(-1);NH_4~+-N、NO_2~--N和NO_3~--N浓度最低,较单养组分别降低27.7%、46.9%和45.1%。【结论】在零换水条件下,异枝江蓠混养密度为456 g/m~2时,更有利于藻体和凡纳滨对虾的生长,对水体中氮浓度的稳定效果最佳。     

岩石中微量钪的吸光光度法测定

在PH5.4—5.9的六次甲基四胺缓冲溶液中,钪与铬天青S(CAS)、氯代十六烷基吡啶(CPC)在乳化剂(OP)存在下生成绿色的三元络合物。络合物摩尔吸收系数为1.86×10~5,总不稳定常数为4.87×10~(-7),钪络合物组成比Sc:CAS:CPC:1:2:3。在0—10μg Sc_2O_3/50ml范围内符合比耳定律。络合物至少稳定8d,并试验了30多种物质对测定钪的干扰。应用于岩石中微量钪的测定,本法与其它方法测定结果一致,回收率在83.00—112.75％之间,变动系数为9.28％。     

海州湾海洋牧场拖网渔获物营养级分析

【目的】分析与对比2014/2018年海州湾同种生物的营养级特征。【方法】根据2018年9月海州湾海洋牧场区渔业资源调查,应用稳定同位素方法计算主要生物的δ~(13)C、δ~(15)N值及营养级,运用系统聚类分析划分主要营养类群(Trophic Group, TG)。【结果】鱼类、虾蟹类、头足类和贝类,营养级范围分别为2.6～4.1、2.7～3.6、2.9～3.3和2.0～3.0。该海域的拖网渔获物可分为3大类群:TG1包括大多数生物类群,由鱼、虾、蟹类和头足类组成;TG2主要为高营养级消费者,包括斑尾刺鰕虎鱼Acanthogobius ommaturus和四指马鲅Eleutheronema tetradactylu;TG3为初级消费者。【结论】2018年海州湾海洋牧场区域同种生物的营养级较2014年明显变高,但也有个别种类的营养级出现不同程度的降低。     

孕震断层的形变模型及其失稳判据

提出了孕震断层的形变模型，讨论了该模型的形变特征，给出了其失稳的临界条件。通过对失稳过程的分析，对孕震期作了新的划分，并给出了失稳临界条件的形变判据。指出：综合使用ＧＰＳ测量、跨断层短基线测量和固体潮观测，可以对孕震的时间进程实施追踪，并可对孕震的危险程度作出判定。     

Parametric Instability Analysis of Deepwater Top-Tensioned Risers Considering Variable Tension Along the Length

Parametric instability of a riser is caused by fluctuation of its tension in time due to the heave motion of floating platform. Many studies have tackled the problem of parametric instability of a riser with constant tension. However, tension in the riser actually varies linearly from the top to the bottom due to the effect of gravity. This paper presents the parametric instability analysis of deepwater top-tensioned risers(TTR) considering the linearly varying tension along the length. Firstly, the governing equation of transverse motion of TTR under parametric excitation is established. This equation is reduced to a system of ordinary differential equations by using the Galerkin method. Then the parametric instability of TTR for three calculation models are investigated by applying the Floquet theory. The results show that the natural frequencies of TTR with variable tension are evidently reduced, the parametric instability zones are significantly increased and the maximum allowable amplitude of platform heave is much smaller under the same damping; The nodes and antinodes of mode shape are no longer uniformly distributed along the axial direction and the amplitude also changes with depth, which leads to coupling between the modes. The combination resonance phenomenon occurs as a result of mode coupling, which causes more serious damage.     

一种精确的非挥发性存储器中高压产生系统的稳定性分析模型

针对高压产生系统在非挥发性存储器中的重要作用,推导出一个用于电流模DC-DC升压转换器稳定性分析的精确模型。该模型综合了传统的脉冲宽度调制模型的简洁性以及离散时间采样系统的精确性,得到一个精确的、具有较强指导意义的传输函数模型。同时,根据推导的结果搭建了一个简洁、直观的仿真电路模型。通过此传输函数模型以及仿真电路模型,可以方便快捷的分析、仿真得到电路中的每一个参数对转化器的增益、电流环稳定性、右半平面零点、输出极点的影响。所介绍的方法也可以直接用于其他DC-DC转化器传输函数的推导。     

非线性Rossby波所满足的三阶Zakharov方程与低频振荡

本文在基本气流具有水平切变的情况下,利用摄动法导出了非线性Rossby波所满足的三阶Zakharov方程,然后,考虑了基流具有弱切变的情况,通过使用三阶Zakharov方程研究了Rossby波列的第一类不稳定性问题。结果表明:通过非线性作用,大气中的Rossby波列可产生调制不稳定。同时,本文对这种不稳定的区域,增长率和周期进行了详细的计算,并讨论了波振幅、波数、纬度和基流切变对它们的影响,指出Rossby波列的调制不稳定可以激发30～60天的低频振荡。     

Numerical Modelling for Dynamic Instability Process of Submarine Soft Clay Slopes Under Seismic Loading

Marine geological disasters occurred frequently in the deep-water slope area of the northern South China Sea, especially submarine landslides, which caused serious damage to marine facilities. The cyclic elastoplastic model that can describe the cyclic stress-strain response characteristic for soft clay, is embedded into the coupled Eulerian-Lagrangian(CEL) algorithm of ABAQUS by means of subroutine interface technology. On the basis of CEL technique and undrained cyclic elastoplastic model, a method for analyzing the dynamic instability process of marine slopes under the action of earthquake load is developed. The rationality for cyclic elastoplastic constitutive model is validated by comparing its calculated results with those of von Mises model built in Abaqus. The dynamic instability process of slopes under different conditions are analyzed. The results indicate that the deformation accumulation of soft clay have a significant effect on the dynamic instability process of submarine slopes under earthquake loading. The cumulative deformation is taken into our model and this makes the calculated final deformation of the slope under earthquake load larger than the results of conventional numerical method. When different contact conditions are used for analysis, the smaller the friction coefficient is, the larger the deformation of slopes will be. A numerical analysis method that can both reflect the dynamic properties of soft clay and display the dynamic instability process of submarine landslide is proposed, which could visually predict the topographies of the previous and post failure for submarine slope.     

基于应力腐蚀和腐蚀疲劳的焊缝磁记忆信号分析

为了研究不同腐蚀条件下的焊缝磁记忆特征信号,对20号钢板状焊缝试件进行残余应力腐蚀、35kN恒拉伸应力腐蚀和35kN静载、25kN动载拉拉腐蚀疲劳对比实验,分析焊缝正、反面磁记忆信号的变化规律,获得焊缝腐蚀发展进程中应力腐蚀与腐蚀疲劳各自对应的磁记忆特征信号.结果表明:在应力腐蚀状态下,不同拉伸载荷对应的磁记忆信号特征不同,35kN恒拉伸应力腐蚀与残余应力腐蚀相比,焊缝区磁记忆信号峰峰值及其梯度更大,磁记忆曲线分布的分散度更大;35kN静载、25kN动载拉拉腐蚀疲劳与35kN恒拉伸应力腐蚀相比,焊缝区磁记忆曲线上下波动多,过零点次数多,磁记忆曲线分布的分散度小.这为磁记忆技术在焊缝工程检测的定性与定量分析提供基础数据.     

联合低轨卫星和地面监测站数据确定导航卫星轨道

探讨同时利用星载数据和地面监测站数据进行导航卫星联合定轨的方法。为验证该方法的有效性,利用2011-03-16~31中国境内7个GPS监测站的观测数据和GRACE-A&B星载数据进行定轨实验。结果表明,在7个国内监测站基础上,加入一颗低轨卫星（GRACE-B）星载GPS数据,GPS可见弧段增加约14%,卫星径向、切向和法向（R、T、N）定轨精度可分别提高约35%、44%和45%;若同时加入GRACE-A和GRACE-B星载数据,可见弧段增加约18%,R、T、N分量精度分别提高约51%、60%和62%。该方法为区域监测站布设条件下导航卫星定轨精度的提升提供了一种新思路。     

E24 profile slope stability analysis in Haizhou Opencast Coal Mine of Fuxin

The E24 profile slope analyzed belongs to a series of excavated slopes of the Haizhou Opencast Coal Mine. It seems to be divided into Downslope Part and Upslope Part. Its profile comprises two noticeable coal seams, called the 8# and 9# weak layers, considered as the potential failure surfaces. In consideration of the actual configuration as in the perspective of any modification, assessing the stability of this slope with various profile forms under given conditions, and assessing the risk of instability and quantifying the influence of earthworks or other modifications to the stability of this slope, have constituted the primordial objectives carried out. From assumed potential failure surfaces, any specific profiles and specified slip surfaces are defined. A factor of safety (FoS) is computed for each specified slip surface; the smallest FoS found corresponds to the least favorable slip surface. The safety factor values obtained are compared to the suggested safety factor. Limit equilibrium methods of vertical slices implemented in Slope/W, computer program for slope stability analyses, have been adopted to perform the E24 slope stability analysis. The safety factor values computed with 9# weak layer are lower than for 8#; the factors of safety obtained with Sarma's method are the smallest; more, without groundwater (long term) overall values are greater than those determined under groundwater condition (short term). The lowest safety factor value is found for a profile depending on an adopted earthwork sequence. The E24 profile slope stability analysis shows the instability risk for the deepest weak layer, and also shows the short and long term stability of this slope for the envisaged earth movements. However it demonstrates the existence of instability risk for any earthwork firstly affecting the downslope part.     

E24 profile slope stability analysis in Haizhou Opencast Coal Mine of Fuxin

The E24 profile slope analyzed belongs to a series of excavated slopes of the Haizhou Opencast Coal Mine. It seems to be divided into Downslope Part and Upslope Part. Its profile comprises two noticeable coal seams, called the 8# and 9# weak layers, considered as the potential failure surfaces. In consideration of the actual configuration as in the perspective of any modification, assessing the stability of this slope with various profile forms under given conditions, and assessing the risk of instability and quantifying the influence of earthworks or other modifications to the stability of this slope, have constituted the primordial objectives carried out. From assumed potential failure surfaces, any specific profiles and specified slip surfaces are defined. A factor of safety (FoS) is computed for each specified slip surface; the smallest FoS found corresponds to the least favorable slip surface. The safety factor values obtained are compared to the suggested safety factor. Limit equilibrium methods of vertical slices implemented in Slope/W, computer program for slope stability analyses, have been adopted to perform the E24 slope stability analysis. The safety factor values computed with 9# weak layer are lower than for 8#; the factors of safety obtained with Sarma's method are the smallest; more, without groundwater (long term) overall values are greater than those determined under groundwater condition (short term). The lowest safety factor value is found for a profile depending on an adopted earthwork sequence. The E24 profile slope stability analysis shows the instability risk for the deepest weak layer, and also shows the short and long term stability of this slope for the envisaged earth movements. However it demonstrates the existence of instability risk for any earthwork firstly affecting the downslope part.     

区域非稳定动力学环境下的工程场地破裂效应初探

工程场地破裂效应是区域非稳定动力学环境下的主要灾害效应之一，但目前对其缺乏系统性研究。本文提出了工程场地破裂效应研究的区域稳定动力学方法，并对非稳定动力学环境下的破裂效应进行了初步探讨。笔者提出非稳定动力学条件决定了破裂原动力，深浅相关性，以及成灾致灾连续性等动力学和运动学特征。