Property Identification of Anomalous Seismic Bodies by GMES Techniques, A Case History

What are the anomalous seismic reflection bodies at depths of over 6000m？Are they reefs or igneous rock？This is a difficult problem for seismic techniques,but the GMES technique can handle it .The GMES technique is a joint exploration technique combining gravity,magnetic,electrical,and seismic techniques.The specific procedure is to conduct a 2D interface-constrained CEMP inversion using 2D seismic and log data followed by a property parameter inversion of the anomalous bodics using gravity and seismic data by the stripping technique.We then estimate the physical properties ofthe anomalous bodies,such as density,susceptibility,resistivity,velocity,and etc.to deduce the geological features of the bodies and provide a basis for drilling decisions.The work in the TZ area reported in this paper shows the applicability of the technique.

Research and Application of In-seam Seismic Survey Technology for Disaster-causing Potential Geology Anomalous Body in Coal Seam

In order to effectively detect potential geology anomalous bodies in coal bearing formation,such as coal seam thickness variation,small faults,goafs and collapse columns,and provide scientific guidance for safe and efficient mining,the SUMMIT-II EX explosion-proof seismic slot wave instrument,produced by German DMT Company,was used to detect the underground channel wave with the help of transmission method,reflection method and transflective method.Region area detection experiment in mining face had been carried out thanks to the advantage of channel wave,such as its great dispersion,abundant geology information,strong anti-interference ability and long-distance detecting.The experimental results showed that:(1)Coal seam thickness variation in extremely unstable coal seam has been quantitatively interpreted with an accuracy of more than 80%generally;(2)The faults,goafs and collapse columns could be detected and predicted accurately;(3)Experimental detection of gas enrichment areas,stress concentration regions and water inrush risk zone has been collated;(4)A research system of disaster-causing geology anomalous body detection by in-seam seismic survey has been built,valuable and innovative achievements have been got.Series of innovation obtained for the first time in this study indicated that it was more effective to detect disaster-causing potential geology anomalies by in-seam seismic survey than by ground seismic survey.It had significant scientific value and application prospect under complex coal seam conditions.

An Expression for Gravity Generated by an Anomalous Geological Body and Its Application in Bathymetry Inversion

The gravity anomaly and vertical gravity gradient due to anomalous geological bodies are mainly computed by numerical methods,so it is difficult and time-consuming to use the gravity-geological method to invert seafloor topography.This paper addresses this issue by deriving an expression for gravity generated by a cylinder based on a series expansion.The choice of number for terms in the series is estimated by comparing with the numerical method,especially when the depth H=4000m,the accuracy of 1 mGal(1 Gal=10^(-2)m/s^(2))can be achieved when the series are 9.The expressions can be used to establish the relationships between the shape of an anomalous body and the generated vertical gravity and vertical gravity gradient,respectively.Finally,the potential applications of the expressions in inverting seafloor topography are illustrated by synthetic examples.

Geologic body three-dimensional model generation and visualization method

The divergence three-dimensional millet-seed body model and the continuous distributing layer-imitating model were introduced, which were used to express geologic body, and the procedure of generating these two models and their merits and demerits were synthesized. Three methods of geologic body’s three-dimensional expression were separately introduced, and the merits of the continuous distributing layer imitating model were proposed as comparing with the divergence three-dimensional millet-seed body model. The three-dimensional cubes were observed from any direction and any tangle with the application of dealing methods such as peeling, hollowing out, transparent or half-transparent.

Three-dimensional analysis of pedicle screw channel,screw entry point and lateral surface of cervical vertebral body

Objective To explore three-dimensional relations of pedicle screw channel (PSC) ,screw entry point and lateral surface of cervical vertebral body by digital techniques. Methods CT scan images of cervical

FINITE-PART INTEGRAL AND BOUNDARY ELEMENT METHOD FOR INTERACTION BETWEEN TWO PARALLEL PLANAR CRACKS IN THREE-DIMENSIONAL FINITE BODIES

By using the Somigliana representation and the concepts offinite-part integrals, a set of hypersingular integral equations ofthe interaction between two parallel planar cracks in a three-dimen-sional finite body subjected to arbitrary loads is derived, and thenits numerical method is proposed by the finite-part integral methodcombined with the boundary element method. According to the analytictheory of hypersingular integral equations, the square root models ofdisplacement discontinuities in the elements near the crack front areapplied, and thus the computational precision is raised. Based onthis, the stress intensity factors can be directly calculated.Finally, the stress intensity factors of sever- al typicalinteraction problems are calculated.

Three-dimensional experimental study of loose top-coal drawing law for longwall top-coal caving mining technology

Based on the loose medium flow field theory, the loose top-coal drawing law of longwall top-coal caving（LTCC） mining technology is studied by using self-developed three-dimensional（3D） test device. The loose top-coal drawing test with shields and the controlled test without shields are performed in the condition without any boundary effect. Test results show that shields will cause reduction in drawing volume of coal in the LTCC mining. The deflection phenomenon of drawing body is also observed in the controlled test, which is verified that the deflection of drawing body is caused by shield. It is found that the deflection angle decreases with increasing caving height, with the maximum value of atailand the minimum value of 0. In addition, the formula to calculate the drawing volume is proposed subsequently.The deflection of drawing body is numerically simulated using particle flow code PFC3 Dand the proposed formula to calculate drawing volume in LTCC is also verified.

Three-Dimensional Prototypes and Evaluation of Their Structure and Form

In order to reveal the appearance of the clothing prototype on the human body,the characteristics of the human body’s structure above the waist section were studied.Based on the experimental data of the fit prototype,three-dimensional prototypes features were comparatively analyzed.And then objectively evaluating the relationship was conducted between the planar structure lines of different prototypes and the human body.The results showed that the prototypes analyzed basically conformed to the size of the human body.However,when they were worn on the human body,there were problems in the structure and forming.The main reason was that the side seam was skewed to different degrees.The results of this study provide reference for many practitioners to choose prototypes.

准确影像定位在颈部食管腔外异物取出术的应用

目的分析颈部食管腔外异物的临床特点及准确影像定位在其诊断和治疗中的应用。方法回顾性分析2017年10月~2024年3月梅州市人民医院耳鼻咽喉科收治的10例颈部食管腔外异物患者,对颈胸部CT行多平面重建(multiplanar reconstruction,MPR),从横断位、冠状位、矢状位判断异物位置,选择合适的手术入路。结果10例颈部食管腔外异物,2例金属和1例木质异物为外伤进入颈部,7例鱼骨为误吞鱼骨迁移颈部。术前影像定位提示异物在环状软骨和甲状软骨周3例,甲状腺内1例,相对应颈椎周2例,胸锁乳突肌周2例,舌骨周2例。支撑喉镜下取出2例,经颈部切开入路取出7例,1例未取出转上级医院治疗。术中彩超协助定位3例。所有患者随访至今均痊愈。结论准确影像定位可为颈部食管腔外异物选择合适手术入路提供依据,术中若异物寻找困难,可借助术中彩超精确定位异物,为成功取出异物提供有力保障。

浅埋深线圈瞬变电磁场超前探测响应及应用

为有效识别隧道工作面前方采空区、岩溶、导水裂隙带等不良地质情况,预防隧道开挖透水事故,开展浅埋深线圈瞬变电磁理论在隧道超前探测中应用的研究。首先,利用COMSOL软件建立浅埋深线圈超前探测模型,研究工作面前方不同方位电磁场的传播特性和异常响应特征;然后,以青岛地铁13号线嘉陵江路站-香江路站区间隧道工程为例,验证浅埋深线圈瞬变电磁法识别异常体的可行性。结果表明:浅埋深瞬变电磁法可有效识别工作面前方不同位置的低阻异常体;不同方位异常体对于电场响应的影响主要体现在响应强度上;瞬变电磁场可有效区别出空气域和岩体域,但受空气域的影响,电磁场在近地表的高阻围岩中衰减速度加快,导致在反演分析中实际探测工作存在高阻异常。

The criterion of anomalous slip at OK in body centered cubic metals

It is generally accepted that anomalous slip(AS) takes place by hexagonal dislocation networks(HDNs) in body centered cubic(BCC) metals,but the role of the HDN formation process in AS has rarely been investigated so far.In this work,the critical yield conditions of the HDNs and isolated dislocations were first calculated,respectively,by molecular statics simulations in two BCC metals.Based on these data,a novel mechanism,entitled as the "conjugated dislocation sources"(CDS),to analyze the formation of the HDNs was proposed for the first time and then incorporated into the criterion of the occurrence of AS.Our prediction is in agreement with experimental observations.Contrary to previous study,it has been revealed that the multiplication of isolated screw dislocations involved in AS has to be considered for correctly understanding the AS origin.

Inducing human induced pluripotent stem cell differentiation through embryoid bodies:A practical and stable approach

Human induced pluripotent stem cells(hiPSCs)are invaluable resources for producing high-quality differentiated cells in unlimited quantities for both basic research and clinical use.They are particularly useful for studying human disease mechanisms in vitro by making it possible to circumvent the ethical issues of human embryonic stem cell research.However,significant limitations exist when using conventional flat culturing methods especially concerning cell expansion,differentiation efficiency,stability maintenance and multicellular 3D structure establishment,differentiation prediction.Embryoid bodies(EBs),the multicellular aggregates spontaneously generated from iPSCs in the suspension system,might help to address these issues.Due to the unique microenvironment and cell communication in EB structure that a 2D culture system cannot achieve,EBs have been widely applied in hiPSC-derived differentiation and show significant advantages especially in scaling up culturing,differentiation efficiency enhancement,ex vivo simulation,and organoid establishment.EBs can potentially also be used in early prediction of iPSC differentiation capability.To improve the stability and feasibility of EB-mediated differentiation and generate high quality EBs,critical factors including iPSC pluripotency maintenance,generation of uniform morphology using micro-pattern 3D culture systems,proper cellular density inoculation,and EB size control are discussed on the basis of both published data and our own laboratory experiences.Collectively,the production of a large quantity of homogeneous EBs with high quality is important for the stability and feasibility of many PSCs related studies.

Effects of lower body positive pressure treadmill on functional improvement in knee osteoarthritis:A randomized clinical trial study

BACKGROUND Knee joint pain and stiffness are the two main symptoms of knee osteoarthritis(OA)and thus restrict a patient’s activities,such as walking and walking up and downstairs.The lower body positive pressure(LBPP)treadmill as one of the emerging body weight support system devices brings new hope for exerciserelated rehabilitation for knee OA patients.AIM To investigate the biomechanical effects and the subjective clinical assessment of LBPP treadmill walking exercise when compared with conventional therapy in mild to moderate knee OA patients.METHODS Eighteen patients with mild-to-moderate knee OA were recruited in this randomized controlled trial(RCT)study.The eligible knee OA patients were randomly assigned to two groups:LBPP and control groups.The patients in the LBPP group performed an LBPP walking training program for 30 min/session per day,6 d per week for 2 wk whereas the patients in the control group performed walking on the ground for the same amount.All patients underwent clinical assessments and three-dimensional gait analysis at pre-and 2-wk post-treatment.RESULTS The Western Ontario and McMaster Universities Arthritis Index and visual analog scale scores in both the LBPP group and control group were found to decrease significantly at the post-treatment point than the pre-treatment point(LBPP:70.25±13.93 vs 40.50±11.86;3.88±0.99 vs 1.63±0.52;control:69.20±8.88 vs 48.10±8.67;3.80±0.79 vs 2.60±0.70,P<0.001).Moreover,compared with the control group,the LBPP group showed more improvements in walking speed(P=0.007),stride length(P=0.037),and knee range of motion(P=0.048)during walking,which represented more improvement in walking ability.CONCLUSION The results of our RCT study showed that the LBPP group has a greater effect on improving gait parameters than the conventional group,although there was no significant advantage in clinical assessment.This finding indicates that LBPP treadmill walking training might be an effective approach for alleviating pain symptoms and improving lower extremity locomotion in mild to moderate knee OA patients.

顺北地区碳酸盐岩断控缝洞体油气产能定量化估算技术

走滑断裂带及其控制的缝洞体是顺北地区奥陶系新的勘探领域,探索断控缝洞体储层单井产量多属性量化预测技术,为顺北地区断裂带井位部署与井轨迹优选提供科学依据和技术支撑。断控缝洞体储层中,断裂是油气运移通道,其纵向延伸和宽度是断裂的通源性,主干断裂与次级断裂平面交汇结构表征断裂的汇聚性,通源性和汇聚性表征成藏断裂特征。断控缝洞体中缝洞是储集空间的主体,断控缝洞体储层规模和断裂裂缝分布密度表征缝洞特征。断控缝洞体储层的单井产量既与断裂特征有关,更与缝洞特征有关。因此,量化的断裂特征和缝洞特征是单井产量量化预测的基础。地震数据及其多种属性的断层精细解释,量化后得到断裂特征值。结构张量属性圈定断控缝洞体储层范围,异常体振幅属性表征缝洞的分布及其体量,最大似然概率属性表征断裂裂缝分布密度,3种属性融合得到缝洞特征值。最后将量化的断裂特征值和缝洞特征值融合为断控缝洞体特征值,与实测钻井的年产液量进行统计分析,得到年产液量与断控缝洞体特征值的统计关系式,实现断控缝洞体储层单井产量的量化预测。

基于深度学习的2D-3D地下密度异常体反演方法

地下密度异常体反演需要由二维数据反演三维结果,为了高效、高精度地反演地下异常体的位置及密度信息,本文提出2D-3D InvNet深度学习反演方法.方法的编-解码器结构,在编码阶段利用二维卷积网络结构提取地表重力异常及重力梯度异常数据信息,解码阶段利用三维卷积网络结构恢复异常体地下形态,实现了二维和三维网络结构的结合.为了精确地反演异常体密度,提出利用加权均方误差(WtdMSE)作为损失函数,同时为了更好地评估反演结果,引入核密度函数作为评价手段.与均方误差(MSE)相比,利用WtdMSE作为损失函数对异常体密度的反演结果更为准确,异常体所在区域的密度误差减少50%以上.对理论样本的反演结果表明,2D-3D InvNet在准确反演异常体地下位置的同时,也能给出准确的密度信息.应用此方法对西澳大利亚Kauring地区实测数据进行反演,我们成功获得了此区域地下异常体的密度分布.理论与实际应用结果表明,2D-3D InvNet深度学习方法稳定且具有较强的泛化性能,能在无需规定限制条件的情况下快速获得准确的反演结果.

Numerical aerodynamic analysis of bluff bodies at a high Reynolds number with three-dimensional CFD modeling

This paper focuses on numerical simulations of bluff body aerodynamics with three-dimensional CFD(computational fluid dynamics) modeling,where a computational scheme for fluid-structure interactions is implemented.The choice of an appropriate turbulence model for the computational modeling of bluff body aerodynamics using both two-dimensional and three-dimensional CFD numerical simulations is also considered.An efficient mesh control method which employs the mesh deformation technique is proposed to achieve better simulation results.Several long-span deck sections are chosen as examples which were stationary and pitching at a high Reynolds number.With the proposed CFD method and turbulence models,the force coefficients and flutter derivatives thus obtained are compared with the experimental measurement results and computed values completely from commercial software.Finally,a discussion on the effects of oscillation amplitude on the flutter instability of a bluff body is carried out with extended numerical simulations.These numerical analysis results demonstrate that the proposed three-dimensional CFD method,with proper turbulence modeling,has good accuracy and significant benefits for aerodynamic analysis and computational FSI studies of bluff bodies.

开平凹陷的拆离作用及构造演化探讨

开平凹陷非典型的凹陷结构以及凹陷中部KP11地质异常体的成因近年来引发了较大争议。本文在阐述开平主洼的拆离作用及其证据的基础上,分析了KP11地质异常体的成因,搭建了开平地区南北向构造格架,恢复了开平凹陷的构造演化过程,并对裂陷期文昌组的两幕伸展作用对沉积的控制进行简要分析。

STUDY OF THREE-DIMENSIONAL SEPARATION OF BOUNDARY LAYER OVER BLUNT BODIES

In the case of three-dimensional flows, the separation can be defined in more than one way. Discussions about three-dimensional boundary layer separation in the literature have found a rational extension of the zero skin friction. Attempts have been made to establish the identity of “separation lines”. Among definitions, these may be found： （1） envelopes of limiting streamlines, （2） lines dividing flow which has come from different regions, （3） lines of singularities （problems of topology）, （4） lines on which some component of the skin friction vanishes. Each of these is valid under certain conditions, but none is universally valid. In the present work, we use the definition （4）, i.e. at low incidence of a blunt body the separation line is identified as the zero of the meridian skin friction component （Wang 1975）. So the separation line on a flattened spheroid （6：3：1） at 6° of incidence is calculated, as well as experimentally determined by using the electrochemical method, which allows to follow the evolution of the parietal velocity gradient.

瞬变电磁法对存在山谷地形时的多个异常体的探测能力研究

以层状地层中的2个三维导电薄板为例,考虑了山谷地形存在时,瞬变电磁法(TEM)分辨地下多个三维异常体的能力。模型计算的结果表明,当有山谷地形存在时,总的异常场由薄板的异常和地形的异常叠加在一起,表明异常场在空间上具有可加性质。在地形平坦时,TEM方法对相同尺寸的近源异常体的分辨能力要优于远源,而且离源越远的异常体异常越小,最后直到无法分辨。但是当存在山谷地形并且把源放在其中时,它们的总异常场叠加后会“放大”远源异常体的异常场,在一定意义上说,这对于分辨远处的异常体更加有利。当异常体在接收器下方埋深不是太大时,不论山谷地形在源处还是接收器处,TEM法对这些异常体的探测能力都是比较好的。2个异常体相距太近时,其异常会叠加在一起,给TEM的分辨增加一些困难。总体表明,在有山谷地形存在时,TEM方法对多个异常体仍具有较好的探测能力。

海洋可控源电磁法三维数值模拟

本文利用美国Sandia国家实验室Weiss编写的3D有限差分程序,通过建立的正演模型,开展3D水平电偶源电磁场特征与异常体空间展布特征(几何特征、埋藏特征)关系的实例研究,并对模型进行了正演数值模拟,得到以下几点认识:①同一位置处接收到的电场强度随着异常体半径的增大而增大,高阻体的存在能够增大电场强度,且异常体越大,场强也越大;②归一化后的电场曲线特征表明,随着发射电流频率的降低,异常体引起的异常越来越小;随着异常体半径增大,引起的异常也逐渐增大;③当异常体半径不变而埋深改变时,随着埋深的增加电场强度逐渐减小,对异常体的分辨力越来越小。文中所得结果对MCSEM电磁场基本传播特性的认识和MCSEM观测资料的解释提供了依据。