Asymmetric Relationship between the Meridional Displacement of the Asian Westerly Jet and the Silk Road Pattern

In previous work, a significant relationship was identified between the meridional displacement of the Asian westerly jet （JMD） and the Silk Road Pattern （SRP） in summer. The present study reveals that this relationship is robust in northward JMD years but absent in southward JMD years. In other words, the amplitude of the SRP increases with northward displacement of the jet but shows little change with southward displacement. Further analysis indicates that, in northward JMD years, the Rossby wave source （RWS） anomalies, which are primarily contributed by the planetary vortex stretching, are significantly stronger around the entrance of the Asian jet, i.e., the Mediterranean Sea-Caspian Sea area, with the spatial distribution being consistent with that related to the SRP. By contrast, in southward JMD years, the RWS anomalies are much weaker. Therefore, this study suggests that the RWS plays a crucial role in inducing the asymmetry of the JMD-SRP relationship. The results imply that climate anomalies may be stronger in strongly northward-displaced JMD years due to the concurrence of the JMD and SRP, and thus more attention should be paid to these years.

APPROACH FOR LAYOUT OPTIMIZATION OF TRUSS STRUCTURES WITH DISCRETE VARIABLES UNDER DYNAMIC STRESS, DISPLACEMENT AND STABILITY CONSTRAINTS

A mathematical model was developed for layout optimization of truss structures with discrete variables subjected to dynamic stress, dynamic displacement and dynamic stability constraints. By using the quasi-static method, the mathematical model of structure optimization under dynamic stress, dynamic displacement and dynamic stability constraints were transformed into one subjected to static stress, displacement and stability constraints. The optimization procedures include two levels, i.e., the topology optimization and the shape optimization. In each level, the comprehensive algorithm was used and the relative difference quotients of two kinds of variables were used to search the optimum solution. A comparison between the optimum results of model with stability constraints and the optimum results of model without stability constraint was given. And that shows the stability constraints have a great effect on the optimum solutions.

Coseismic gravity and displacement changes of Japan Tohoku earthquake(Mw 9.0)

The greatest earthquake in the modern history of Japan and probably the fourth greatest in the last 100 years in the world occurred on March 11, 2011 off the Pacific coast of Tohoku.Large tsunami and ground motions caused severe damage in wide areas, particularly many towns along the Pacific coast. So far, gravity change caused by such a great earthquake has been reported for the 1964 Alaska and the 2010 Maule events. However, the spatial-temporal resolution of the gravity data for these cases is insufficient to depict a co-seismic gravity field variation in a spatial scale of a plate subduction zone. Here, we report an unequivocal co-seismic gravity change over the Japanese Island, obtained from a hybrid gravity observation（combined absolute and relative gravity measurements）. The time interval of the observation before and after the earthquake is within 1 year at almost all the observed sites, including 13 absolute and 16 relative measurement sites, which deduced tectonic and environmental contributions to the gravity change. The observed gravity agrees well with the result calculated by a dislocation theory based on a self-gravitating and layered spherical earth model. In this computation, a co-seismic slip distribution is determined by an inversion of Global Positioning System（GPS） data. Of particular interest is that the observed gravity change in some area is negative where a remarkable subsidence is observed by GPS, which can not be explained by simple vertical movement of the crust. This indicated that the mass redistribution in the underground affects the gravity change. This result supports the result that Gravity Recovery and Climate Experiment（GRACE） satellites detected a crustal dilatation due to the 2004 Sumatra earthquake by the terrestrial observation with a higher spatial and temporal resolution.

Classification Study on Relative Permeability Curves

The classification method of relative permeability curves is rarely reported, when relative permeability curves are applied;if the multiple relative permeability curves are normalized directly, but not classified, the calculated result maybe cause a large error. For example, the relationship curve between oil displacement efficiency and water cut, which derived from the relative permeability curve in LD oilfield is uncertain in the shape of low water cut stage. If being directly normalized, the result of the interpretation of the water flooded zone is very high. In this study, two problems were solved: 1) The mathematical equation of the relationship between oil displacement efficiency and water cut was deduced, and repaired the lost data of oil displacement efficiency and water cut curve, which solve the problem of uncertain curve shape. After analysis, the reason why the curve is not available is that relative permeability curves are not classified and optimized;2) Two kinds of classification and evaluation methods of relative permeability curve were put forward, the direct evaluation method and the analogy method;it can get the typical relative permeability curve by identifying abnormal curve.

Quantitative prediction of oil saturation of unconsolidated sandstone reservoir based on time-lapse seismic “relative difference method”: Taking Zeta oil field in West Africa as an example

In view of the disadvantage that the absolute difference of time-lapse seismic(the difference between monitoring data and base data) is not only related to the change of oil saturation, but also closely related to the thickness of reservoir, a time-lapse seismic "relative difference method"(the ratio of monitoring data to base data) not affected by the thickness of reservoir but only related to the change of fluid saturation, is proposed through seismic forward modeling after fluid displacement simulation. Given the same change of fluid saturation, the absolute difference of time-lapse seismic conforms to the law of "tuning effect" and seismic reflection of "thin bed", and the remaining oil prediction method based on absolute difference of time-lapse seismic is only applicable to the reservoirs with uniform thickness smaller than the tuning thickness or with thickness greater than the tuning thickness. The relative difference of time-lapse seismic is not affected by reservoir thickness, but only related to the change of fluid saturation. It is applicable to all the deep-sea unconsolidated sandstone reservoirs which can exclude the effect of pressure, temperature, pore type and porosity on seismic. Therefore, the relation between the relative difference of time-lapse seismic and the change of fluid saturation, which is obtained from seismic forward modeling after Gassmann fluid displacement simulation, can be used to quantitatively predict the change of reservoir water saturation and then the distribution of the remaining oil. The application of this method in deep sea Zeta oil field in west Africa shows that it is reasonable and effective.

Method for determining the position of landslide slip-surface with a typical inclinometric curves

In the actual monitoring of deep hole displacement,the identification of slip surfaces is primarily based on abrupt changes observed in the inclinometric curve.In conventional identification methods,inclinometric curves exhibiting indications of sliding can be categorized into three types:B-type,D-type,and r-type.The position of the slip surface is typically determined by identifying the depth corresponding to the point of maximum displacement mutation.However,this method is sensitive to the interval of measurement points and the observation scale of the coordinate axes and suffers from unclear sliding surfaces and uncertain values.Based on the variation characteristics of these diagonal curves,we classified the landslide into three components:the sliding body,the sliding interval,and the immobile body.Moreover,three different generalization models were established to analyze the relationships between the curve form and the slip surface location based on different physical indicators such as displacement rate,relative displacement,and acceleration.The results show that the displacement rate curves of an r-type slope exhibit a clustering feature in the sliding interval,and by solving for the depth of discrete points within the step phase,it is possible to determine the location of the slip surface.On the other hand,D-type slopes have inflection points in the relative displacement curve located at the slip surface.The acceleration curves of B-type slopes exhibit clustering characteristics during the sliding interval,while the scattered acceleration data demonstrate wandering characteristics.Consequently,the slip surface location can be revealed by solving the depth corresponding to the maximum acceleration with cubic spline interpolation.The approach proposed in this paper was applied to the monitoring data of a landslide in Yunnan Province,China.The results indicate that our approach can accurately identify the slip surface location and enable computability of its position,thereby enhancing applicability and reliability of the deep-hole displacement monitoring data.

Formation around planetary displaced orbit

The paper investigates the relative motion around the planetary displaced orbit. Several kinds of displaced orbits for geocentric and martian cases were discussed. First, the relative motion was linearized around the displaced orbits. Then, two seminatural control laws were investigated for each kind of orbit and the stable regions were obtained for each case. One of the two control laws is the passive control law that is very attractive for engineering practice. However, the two control laws are not very suitable for the Martian mission. Another special semi-natural control law is designed based on the requirement of the Martian mission. The results show that large stable regions exist for the control law.

Calculation of reverse-fault-related parameters using topographic profiles and fault bedding

Fault-related parameters are critical for studying tectonic evolution, deformation character- istics, active tectonism, and seismic hazards. A new method of calculating reverse-fault- related parameters has been developed, which uses systematic analysis of the geometrical characteristics of normal and reverse scarps of reverse faults together with measurements of topographic profiles and fault bedding. The results show that the most suitable method of calculating fault parameters heavily relies on the specific type of fault scarp. For a reverse scarp, the size of the vertical displacement （VD） of the fault, the vertical separation （VS） of the hanging wall and the footwall, and the fault scarp height （SH）how the relationship VD ≥VS ≥ SH; conversely, for normal scarps, VD ≤ VS ≤ SH. The theoretical equations were used to study fault deformation in the Southwest Tianshan Mountain foreland basin. The results showed that, for every fault, VD ≥ VS ≥SH, which is consistent with our predicted relationship. This finding demonstrates that this method is suitable to explore structural information of reverse faults. In the study area, the vertical displacement is 1.4 times the horizontal displacement, suggesting that fiexural-slip faults may play an important role in transferring local deformation from horizontal shortening to vertical uplift. Therefore, one of the most important steps in correct calculation of reverse-fault-related parameters is selection of the proper equations by identifying the specific type of fault scarp and the corresponding calculation method.

冻融环境下泡沫混凝土的单轴压缩特性

为了解冻融环境下泡沫混凝土的单轴压缩特性,分别对4种密度(500、600、800和1 000 kg/m3)的泡沫混凝土进行了变加载速率(10~100 N/s)的试验研究,并基于X-CT重构了冻融环境下泡沫混凝土的孔隙结构模型。在此基础上,研究了单轴压缩过程荷载-位移曲线的特征及其影响因素,并借助回归分析和灰关联理论分析了泡沫混凝土密度、冻融循环次数及加载速率与抗压强度的关联程度。结果表明:冻融循环后泡沫混凝土单轴压缩过程荷载-位移曲线的切线模量大幅减小,非线性特征加强;冻融循环后试件孔隙率增大,孔径分布离散化程度加强。冻融环境下泡沫混凝土抗压强度与密度等级之间始终保持指数关系,相关系数均在0.9以上;泡沫混凝土密度等级与抗压强度联系最为紧密,其次是冻融循环次数和加载速率,灰关联度均在0.65以上。

锚定板位移-荷载关系近似解析算法

首先,通过适当的假设,基于弹性地基梁理论,提出了黏性土中锚定板位移-荷载关系的近似解析算法。其次,基于6个不同尺寸方形锚定板位移-荷载关系的数值模拟结果,获得了土体水平基床系数的比例系数与锚定板水平位移关系式中的两个拟合参数。然后,用锚定板现场抗拔力试验结果验证了理论分析方法的可行性。最后,讨论了土的黏聚力及内摩擦角对锚定板抗拔承载力的影响。研究结果表明,在某一深度范围内方形锚定板位移-荷载关系近似解析算法是可行的。

低硬度橡胶隔震支座基本力学性能及恢复力特性

本研究对低硬度橡胶隔震支座的材料性能 (主要包括力学性能 )进行了系统的试验开发及理论研究。研究用低硬度橡胶隔震支座包括天然橡胶隔震支座及铅芯橡胶隔震支座两大类 18种规格总计近 30个大直径隔震支座。研究内容涉及橡胶隔震支座竖向刚度、水平刚度及阻尼等基本力学性能 ;压缩界限 ,屈曲及极限剪切变形等界限性能 ;温度、压力、剪切变形、老化和徐变等相关性及长期特性 ;同时还对橡胶材料其他性能进行了系统的试验研究。本文主要介绍低硬度天然橡胶隔震支座及铅芯橡胶隔震支座的基本力学性能 ,如竖向。

螺旋桩基础抗拔试验研究

异型的桩体几何形式增加了抗拔螺旋桩的桩土相互作用复杂性,抗拔试验研究有利于了解螺旋桩基础的承载机制和影响因素。通过16次原型桩抗拔试验,实测了单桩上拔荷载-位移曲线(U-Z曲线),该曲线表现出多拐点、渐进型特点,采用单位荷载的桩顶位移变化率、桩顶位移增量以及结合地基变形特征的方法判定了3种桩型的抗拔极限荷载。用U-Z曲线、lgU-Z曲线和P/Pu-Z曲线初步分析了桩体埋深、深宽比、首层叶片埋置深度以及叶片距宽比等参数对螺旋桩基础抗拔承载性状的影响。试验表明,抗拔螺旋桩的埋深、首层叶片埋置深度和叶片距宽比存在临界点,影响桩土的工作性状和破坏模式。

复方倍他米松局部注射后自体髓核移植模型大鼠脊髓及背根神经节中P物质和降钙素基因相关肽变化

背景:复方倍他米松注射液治疗椎间盘突出症临床应用广泛,但其具体作用机制尚不明确。目的:探讨局部注射复方倍他米松对自体髓核移植模型大鼠脊髓及背根神经节中P物质和降钙素基因相关肽的影响。方法:36只SD大鼠随机分为4组,即:空白组、模型组、假手术组、西药组,每组9只。模型组和西药组适应性喂养1周后手术制作大鼠自体髓核移植模型。于术后第3,7,12天,模型组和假手术组给予128.25μL生理盐水,西药组给予复方倍他米松注射液13.5μL+2%利多卡因注射液67.5μL。末次给药12 h取L4-6节段脊髓及背根神经节,采用免疫荧光染色方法测定两种组织中P物质和降钙素基因相关肽的含量。结果与结论:各组大鼠脊髓、背根神经节中P物质和降钙素基因相关肽平均荧光强度比较,差异有显著性意义(P<0.01),进一步两两比较:与空白组、假手术组相比较,模型组大鼠脊髓、背根神经节中P物质和降钙素基因相关肽含量显著性增高(P<0.01),证明模型复制可靠;与模型组、假手术组相比较,西药组大鼠脊髓、背根神经节中P物质和降钙素基因相关肽含量显著性降低(P<0.01)。结果表明复方倍他米松治疗腰椎间盘突出症的作用机制,可能是通过抑制背根神经节神经元合成和分泌P物质,清除背根神经节中P物质和降钙素基因相关肽,减少其向脊髓传递,从而抑制和缓解疼痛。

灰色相关性分析在结构静力损伤识别中的应用

基于灰色理论的相关性分析方法,首次提出了灰色曲率关联系数的概念并将其应用到结构的静力损伤识别中,提出了对局部损伤十分敏感的静态位移曲率置信因子SDCACi,通过该因子的大小对各节点所连接的单元是否会发生损伤进行精确的判断,然后运用最小二乘法对损伤区域的损伤程度进行识别.并将该方法应用于两端固支梁的损伤识别中,由识别结果可以证明:不论测量数据(用有限元仿真计算并考虑了测量误差)的多少,该方法对结构中的单损伤和多损伤都能进行准确的定位,因此该方法在大型结构及复杂结构的损伤识别中具有广阔的应用前景.

汽车动力总成悬置系统位移控制设计计算方法

论述了动力总成位移控制设计的一般原理。以一轿车动力总成4点悬置系统为例,针对汽车的一特殊行驶工况,对动力总成的质心位移、悬置位移和支承点反力进行了计算。文中论述的动力总成位移控制的设计思想和计算方法对汽车动力总成的设计具有指导意义。

南天山库车秋里塔格褶皱带三维构造分析

笔者利用库车秋里塔格地区3000km的二维地震反射资料,结合地表构造测量成果,分段叙述秋里塔格褶皱带的构造几何学和运动学性质,说明构造交汇部位断层和褶皱的叠加过渡关系,并通过二维构造剖面的组合,建立秋里塔格褶皱带的三维构造几何模型。研究发现秋里塔格褶皱带为浅部断层传播褶皱与深部断层转折褶皱叠加形成的复合型背斜带,深部台阶状逆断层的叠加作用、叠加断层位移量的转换、断层断坡高度的变化造成地表背斜沿走向发生变化,笔者通过测量断层叠加方式、断层位移量转换、断层断坡高度,说明秋里塔格褶皱带背斜叠加、扭曲、分叉现象的构造机理,并且给出了秋里塔格褶皱带断层的滑移量。

地图综合中目标空间关系维护

在地图综合的过程中,比例尺的变化以及各种综合算子都可能导致目标产生空间关系冲突。以往在对空间关系进行维护时,通常只是对拓扑关系变化进行探测与控制。由于方向关系是人们在日常生活中用途最为广泛的空间关系,研究在地图综合中如何有效维护目标间的方向关系具有重要的科学意义。本文采用定性空间推理的方法,建立考虑目标方向关系的移位安全区,从而可以综合检测与控制拓扑关系与方向关系的冲突及其传播,并就本方法存在的问题和今后的研究方向提出了一些看法和思路。

基于多色集合理论的产品装配规划建模与算法研究

采用多色集合理论建立了一种用数组元素表示的装配关系模型,它包括表示定位关系的定位基准模型和表示装配通道关系的可能位移模型.通过定位基准方程组和可能位移方程组给出了这种装配关系模型的数学表达形式,并提出了它们的求取算法,从而将装配过程中的定位关系和装配通道关系这2种约束关系用简单的逻辑方程式表示出来,方便了计算机的编程.同时,提出的各级装配单元的生成算法和在装配单元基础上建立递阶结构图的算法,为用计算机编程实现装配序列的自动生成提供了基础.与传统的装配规划模型相比较,用多色集合理论进行装配规划建模,便于描述装配过程中的约束关系,具有形式化水平高、避免“组合爆炸”和易于编程等优点.

基于动态肌电图的腰椎间盘突出症诊治和相关因素研究

目的:分析腰椎间盘突出症(lumbar disc herniation,LDH)患者腰背部肌肉活动的动态肌电特征及相关因素,阐明动态肌电在腰椎间盘突出症患者诊治过程中的临床意义。方法:自2014年9月至2021年3月,采用表面肌电图遥测仪检测40例腰椎间盘突出症患者,男14例,女26例;年龄20~61(40.68±10.56)岁;病程1~120(17.75±27.56)个月。另外招募12例正常人作为对照组,男2例,女10例;年龄24~53(36.50±10.30)岁。对所有受试者进行静止站立、躯干屈伸过程中的近胸段竖脊肌、腰段竖脊肌、多裂肌的动态肌电测试。比较两组受试者肌电活动数据(肌电振幅、中位频率、原始肌电图形),分析腰椎间盘突出症患者一般资料与肌电活动数据的相关性。结果:静止站立时,腰椎间盘突出症LDH组受试者右侧及左侧近胸段竖脊肌肌电振幅值较对照组增大(P<0.05)。躯干屈伸时,LDH组受试者右侧及左侧近胸段竖脊肌、腰段竖脊肌、多裂肌肌电振幅均较对照组增大(P<0.05);躯干屈伸时,LDH组受试者右侧及左侧近胸段竖脊肌、腰段竖脊肌、多裂肌中位频率均较对照组增大(P<0.05);躯干屈伸时,LDH组受试者的原始肌电图形与对照组相比明显不同,LDH组受试者的躯干最大限度屈曲维持过程中所测腰背肌肉的肌电活动存在高水平,原始信号中应该规律出现的肌电静止信号不能分辨;躯干屈伸时,LDH组受试者的性别、年龄、体重、身高分别与双侧近胸段、腰段竖脊肌和双侧多裂肌的肌电振幅、中位频率无相关性(P>0.05)。结论:腰椎间盘突出症患者腰背部肌肉存在不同于正常人的特征性表面肌电改变,这些特征更能客观地反映患者的肌肉情况,可以成为腰椎间盘突出症患者诊断和治疗效果评价的有效指标。由此可见,表面肌电图不单是一种检测手段,其可被考虑在LDH的常规诊疗计划之内来指导临床工作。

土压力-位移关系的应力路径试验研究

提出了一种通过应力路径试验研究土压力-位移关系的方法。通过室内应力路径试验得到了土压力-应变关系,结合由理论分析得到的位移-应变关系,最终得到土压力-位移关系。与某实例的有限元模拟结果对比,证明该方法是有效的。