LBM simulation of fluid flow in fractured porous media with permeable matrix

To analyze and depict complicated fluid behaviors in fractured porous media with variably permeable matrix,an integrated discrete computational algorithm is proposed based on lattice Boltzmann method（LBM）.This paper combines with the external force model and statistical material physics to effectively describe the feature changes while the fluid passes through the fractures within the permeable matrix.As an application example,a two dimensional rock sample is reconstructed using the digital image and characterized with different feature values at each LBM grid to distinguish pores,impermeable and permeable matrix by stating its local physical property.Compared with the conventional LBM,the results demonstrate the advantages of proposed algorithm in modeling fluid flow phenomenon in fractured porous media with variably permeable matrix.

Rock matrix-fractured media model for heterogeneous and fractured coal bed

Coal was considered rock matrix-fractured media composed of rock matrix and fractures, and the rock matrix-fractured media model for heterogeneous and fractured coal bed was presented. In this model the rock matrix is heterogeneous, and the mechanical parameters such as elastic modulus and strength follow Weibull distribution. Fractures in coal bed were generated with the discrete fracture network method, and the properties of fractures were simulated with Desai element. Then the virtual generating system (VGS) of natural heterogeneous and fractured coal bed was developed in Matlab 6.0. The coupled model of gas flow and deformation process based on the rock matrix-fractured media model method and VGS for heterogeneous and fractured coal bed was presented, and the numerical code was developed in Matlab 6.0. The gas flow process in the heterogeneous and fractured coal bed was simulated in a numerical case. The main conclusions are: 1) The natural heterogeneous and fractured coal bed could be simulated by the rock matrix-fractured media model and VGS; 2) The fractures connected with the well have much more effects on gas flow than those non-connected.

Recursive Asymptotic Hybrid Matrix Method for Acoustic Waves in Multilayered Piezoelectric Media

This paper presents the recursive asymptotic hybrid matrix method for acoustic waves in multilayered piezoelectric media. The hybrid matrix method preserves the numerical stability and accuracy across large and small thicknesses. For discussion and comparison, the scattering matrix method is also presented in physics-based form and coherent form. The latter form resembles closely that of hybrid matrix method and helps to highlight their relationship and distinction. For both scattering and hybrid matrix methods, their formulations in terms of eigenwaves solution are provided concisely. Making use of the hybrid matrix, the recursive asymptotic method without eigenwaves solution is described and discussed. The method bypasses the intricacies of eigenvalue-eigenvector approach and requires only elementary matrix operations along with thin- layer asymptotic approximation. It can be used to determine Green’s function matrix readily and facilitates the trade-off between computation efficiency and accuracy.

Quantitative criteria for identifying main flow channels in complex porous media

To identify the type of main flow channels of complex porous media in oil and gas reservoirs,the"main flow channel index"is defined as the ratio of comprehensive permeability obtained from well test to matrix permeability obtained from core analysis or well logging.Meanwhile,a mathematical model is established based on equivalent flow assumption,the classification method for main flow channels is put forward,and quantitative characterization of main flow channels is realized.The method has been verified by analysis of typical gas reservoirs.The study results show that the"main flow channel index"can quantitatively classify types of flow channels.If the index is less than 3,the matrix pore is the main flow channel;if the index is between 3 and 20,the fracture is the main flow channel and the matrix pore acts as the supplement one;if the index is more than 20,the fracture is the only seepage channel.The dynamic analysis of typical gas reservoirs shows that the"main flow channel index"can be used to identify the type of flow channel in complex porous media,guiding the classified development of gas reservoirs,and avoiding development risk.

ON FREE WAVE PROPAGATION IN ANISOTROPIC LAYERED MEDIA

The method of reverberation-ray matrix （MRRM） is extended and modified for the analysis of free wave propagation in anisotropic layered elastic media. A general, numerically stable formulation is established within the state space framework. The compatibility of physical variables in local dual coordinates gives the phase relation, from which exponentially growing functions are excluded. The interface and boundary conditions lead to the scattering relation, which avoids matrix inversion operation. Numerical examples are given to show the high accuracy of the present MRRM.

Seismic Wave Propagation and Excitation in Multi-layered Media with Irregular Interfaces Part (Ⅰ): SH Case

Study of seismic wave excitation and propagation in laterally heterogeneous media was an active and important subject in seismology in the past two decades, numerous analytical and numerical efforts have been made in this research field. In this article, I have, first, made a brief review on those developments and then introduced and summarized a unified and efficient method, global generalized reflection-transmission (abbreviated to R/T thereafter) matrices method, for synthetic seismograms in multi-layered media with irregular interfaces developed by the author [24~26]. As demonstrated in this article, this method could be regarded as an extension of the generalized R/T coefficients method for the horizontally layered case [2,5] to the layered media with irregularly shaped interfaces by incorporating the T matrices technique [27,28]. Because of the use of a recursive scheme in computing the global generalized R/T matrices, this method is efficient, particularly for the case with a large number of

科学家精神的具象化传播:叙事体系、媒体矩阵与互动机制

在新时代主流意识形态走向具象化传播的趋势下,科学家精神在全媒体传播生态中仍存在传播范围有限、针对性与传播力不强的现实困境。因此,科学家精神传播的跨媒介叙事体系应当建立“元叙事体系搭建—跨媒介传播调试—自互动参与机制”的科学家精神传播路线,搭建有效的叙事框架,建立起跨媒介、多模态的科学家精神传播渠道,构建科学家精神传承与传播的互动参与机制,将叙事体系、媒体矩阵、互动机制有机结合,以达到对科学家精神更为精准和有效的传播。

媒介信任度提升视角下的融媒体矩阵传播协同效应优化

掌握信息化条件下舆论主导权、广泛凝聚社会共识,是巩固壮大主流思想文化的必然要求。融媒体矩阵中各媒体承担着不同的宣传要求,需要结合自身优势发挥不同的影响效力,以传播态度的正向、正确而发挥各自长处,实现优势互补。融媒体矩阵传播效应发挥应致力于报道内容的纵深创作发展,进行真实客观却又极具宽度与厚度的舆论引导。发挥好融媒体矩阵在传播上“内容生产+产品形态+渠道占有”的一体化优势,提升报道宽度与深度、打造多样风格。不断强化宣传工作顶层设计,提升融媒体矩阵的传播力;加强复合型人才培养,提升融媒体矩阵的影响力;掌握社会舆论主导权,提升融媒体矩阵的引导力;优化受众沉浸式体验,提升融媒体矩阵的公信力。

国家公共文化云新媒体矩阵建设:底层逻辑、实践现状及优化路径

优化国家公共文化云新媒体矩阵,是促进公共数字文化传播、满足群众文化服务需求的重要内容,亦是提升公共文化服务效能的有效方式。论文从国家公共文化云新媒体矩阵建设的底层逻辑出发,通过网络调研方法,结合5W模式对国家公共文化云新媒体矩阵的现状进行分析,研究发现该矩阵目前存在内容同质亟待优化、矩阵联动尚待加强、受众需求仍待跟进、传播效果有待提升等问题,应从深化表达形式、注重矩阵协同、明确需求差异、完善服务机制等方面进行优化。

新媒体矩阵视域下江西文学经典的传播力提升

在新媒体飞速发展的时代背景下,文学经典的传播媒介和传播环境在不断更新和变化。借助新媒体矩阵传播文学经典,理应成为提升文学经典传播力的重要抓手,但这在以往的研究中并未引起足够的重视。本研究基于文学与传播学的学科交叉融合,考察江西文学经典传播现状,探寻“新媒体矩阵+文学经典”的文学传播理论和研究范式。研究发现,构建新媒体矩阵并采用新媒体表达方式和呈现形式进行对外传播,能有效提升江西文学经典的传播力。

融媒体视域下高校新媒体矩阵传播策略研究

随着信息技术的飞速发展,融媒体时代已经到来,传统媒体与新媒体的深度融合成为传播领域的新趋势。高校作为知识传播与人才培养的重要阵地,其新媒体矩阵在信息传播、文化引领等方面发挥着举足轻重的作用。然而,面对融媒体带来的挑战与机遇,高校新媒体矩阵如何调整传播策略,以更好地服务师生、提升影响力,成为亟待解决的问题。对此,本文旨在探讨融媒体视域下高校新媒体矩阵的建设现状及其传播策略,以期为教育工作者提供参考和借鉴。

科技期刊集群化发展与服务能力建设研究

我国科技期刊集群化建设已经取得了重要进展,对促进科技期刊的发展发挥了重要作用,但在集群化服务能力方面还需要进一步提升,加强对科技期刊集群化服务能力建设的研究具有重要的意义。文章分析了当前国内期刊集群化建设模式,总结了同一主管或主办主体集约化期刊集群和联盟式期刊集群两种主要的集群模式。对推动科技期刊发展,这两种模式都取得了很好的成效,但也存在产业能力、发展合力和服务能力上的不足。结合存在的不足,文章指出科技期刊集群的发展方向,除了要聚焦于期刊影响力和评价指标的提升,还应加强对学科的服务能力,自身的产业能力以及提高对作者读者的服务能力方面的建设,加强期刊集群全媒体矩阵能力的建设。文章介绍了《金属矿山》在集群化建设方面进行的探索,通过建设地方性期刊集群和数字化期刊集群,来提升期刊的综合服务能力。

当代生态环境类政务公众号的发展前景和进化路径——以“广东生态环境”政务微信公众号为例

本文从“广东生态环境”政务微信公众号(以下简称“粤环微信公众号”)建设历程、运营情况、经验总结等方面,综合评价其所取得的成效,阐述粤环微信公众号起到的推进环境治理现代化、促进公众参与的积极作用,探索当前技术不断革新、手段日趋丰富的情况下,政务公众号的发展前景和进化路径。

医药企业新媒体矩阵传播策略研究——以亚宝药业为例

本文从面向目标消费者(B2C),以及面向企业、利益相关方(B2B)两个维度入手分析了亚宝药业不同新媒体平台公号的传播目标和传播效果。研究发现,亚宝药业通过对新媒体矩阵的统合管理,初步形成“传播系统合力”,辐射各自不同的目标受众人群,公号间相互联系支撑,发挥出立体化传播的优势。研究建议,亚宝药业建立跨部门沟通机制,拓展矩阵宽度,创新传播形式,促进新媒体矩阵进一步提升竞争力。

短视频平台对大学生思想政治教育的影响与对策探研

随着互联网技术的高速发展以及智能手机的广泛普及,短视频行业迅速发展壮大,短视频逐渐成为自媒体时代下人们消遣娱乐、记录生活的重要方式。而短视频的发展对大学生思想政治教育工作来说,既是机遇,也是挑战。文章结合教学实践,在阐述短视频平台特点的基础上,分析其对大学生思想政治教育的积极影响与消极影响,探究发挥短视频平台在大学生思想政治教育中作用的有效对策,旨在为新形势下大学生思想政治教育工作提供方法借鉴。

隔离层下单漏斗放矿力链演变的参数敏感性分析

利用PFC软件,以同步充填留矿法为背景,选取隔离层厚度A、隔离层界面摩擦因数B、矿石颗粒摩擦因数C及颗粒半径D作为正交试验的四种影响因素,对力链特征参数的一般变化规律进行分析,研究影响力链演变的参数及其敏感性。结果表明:力链数量先减少后增加;力链长度的概率分布曲面呈指数形式递减,短力链所占比例逐渐减少,长力链所占比例逐渐增加;力链强度表现出先减少后增加的规律;力链强度的概率分布先呈指数式上升,后呈指数式递减;四种因素对正交试验指标影响的主次顺序为CDAB;对应的最优方案为颗粒摩擦因数0.8、颗粒半径0.008 m、隔离层厚度0.004 m、隔离层界面摩擦因数0.5,此时散体介质体系在放矿过程中最为稳定。

移动AR+VR支持下跨媒体视频关键帧还原仿真

为了准确还原视频信息,针对跨媒体视频帧间保真度以及压缩比较低的问题,设计一个移动AR+VR支持下的跨媒体视频关键帧还原方法。采用SIFT方法提取跨媒体视频关键帧特征点,反复提取关键帧,构成一个关键帧集合,采用AR+VR技术按照属性与特征建立全景画面AR预测模型,校正全景图,建立匹配矩阵,匹配VR视频帧间序列,实现移动AR+VR支持下跨媒体视频关键帧还原。实验结果表明,应用该方法后,准确性、保真度以及压缩比较高,具有较好的关键帧还原效果。

复杂多孔介质主流通道定量判识标准

为判识油气储集层中复杂多孔介质的主流通道类型,利用试井解释获取的综合渗透率与岩心测试(或测井解释)得到的基质渗透率的比值定义了“主流通道指数”,同时基于流量等效原理建立了相应的数学模型,提出了主流通道分类方法,实现了储集层流动通道类型的定量表征,并通过典型气藏实例分析验证了该方法的有效性。研究表明,“主流通道指数”能够定量划分流动通道类型:该指数小于3,基质孔隙为主要流动通道;该指数为3~20,流动通道以裂缝为主、基质孔隙为辅;该指数大于20可视裂缝为唯一渗流通道。典型气藏的动态分析显示,“主流通道指数”可用于评价多孔介质流动通道类型,进而指导气藏分类开发、规避气藏开发风险。

面向群组的社交follow推荐方法研究

目前社交网络中的推荐方法主要是针对单个的个体用户,然而随着日益频繁的社交活动,若干相关用户自然形成了群组,研究如何对于整体的群组用户进行推荐的问题引起了国内外学者的兴趣.本文在优化和改进面向个体的社交follow关系推荐算法的基础上,提出基于矩阵分解和混合策略的群组用户推荐方法.首先,对社交媒体微博中用户-项目矩阵进行奇异值(SVD)分解,然后提出在SVD中加入用户的社交行为和社交关注关系特征,并用随机梯度下降(SGD)算法优化对个体用户推荐的预测评分.其次,在获得个体的推荐评分基础之上,设计一种混合融合策略,该策略融合群组中个体成员的推荐评分形成对该群组的整体评分,从而实现对于群组用户的推荐.最后,实验采用KDDCUP2012竞赛Track1的数据,以平方根误差为评估指标,对比个体推荐中传统SVD模型和本文提出的SVD优化模型,并进一步对比本文提出的混合融合策略与传统的最大满意度、平均满意度及最小忍耐度三种单一融合策略.实验结果表明SVD优化模型优于传统SVD模型,并且采用混合的策略要优于单一的群组融合策略.总体上,本文提出的推荐方法能够有效提高群组推荐的准确度.

煤层气井突然产气机理分析

煤层气井开采时一般先排水后采气,且见气时的产量不是缓慢而是突然升高。为了弄清煤层气井突然产气的机理,从煤储层的结构、产气过程等方面进行了深入分析和研究。结果表明:煤岩储层微观上为双重介质,由割理(裂缝)和基质岩块2个系统组成;割理和基质孔隙中均充满了地层水,煤层气为赋存在基质中的吸附气,需排水降压解吸后才能被采出;刚解吸出的少量气体饱和程度较小,多以气泡的形式分散在基质孔隙水中,由于受到基质毛管压力的限制,这些气体无法流动;随着解吸气量增多,气泡逐渐变成连续相,气体的饱和程度增加,压力升高,流动性也有所增强,但是煤岩基质孔隙一般较小,毛管压力较高,很多气体仍被限制在基质孔隙中,只有当气体压力升高到突破毛管压力之后,大量的解吸气才会倾泻到割理中,致使煤层气井产气量突然升高。煤层气井的产气压力低于解吸压力,而煤层气的解吸压力其实就是地层水的饱和压力或泡点压力。在煤层气开采过程中,可以采取相应节流措施来控制煤层气井的产量变化,以达到稳产及保护煤层和生产管柱的效果。